Science.gov

Sample records for promieniowanie uv-c lub

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

    DOE PAGES

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

    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

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

    PubMed

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

    2016-06-01

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

  3. Investigation of monoclonal antibodies directed against Fy3, Jra, Lub, Kell or Kell related antigens.

    PubMed

    Janvier, D; Veaux, S; Benbunan, M

    1997-01-01

    Twenty Mabs of human or murine origin were studied. Serological characterization was achieved by the gel technique with common, rare, and enzyme-modified RBCs. Three clones bound to cell surface proteins on immunoblots: 1 anti-Lub and 2 Mabs raised to a purified Kell glycoprotein. Four anti-K Mabs precipitated the expected 93kD protein and a dimeric form under non-reducing conditions.

  4. 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.

  5. Synthesis and characterization of a lubricin mimic (mLub) to reduce friction and adhesion on the articular cartilage surface.

    PubMed

    Lawrence, Alexandra; Xu, Xin; Bible, Melissa D; Calve, Sarah; Neu, Corey P; Panitch, Alyssa

    2015-12-01

    The lubricating proteoglycan, lubricin, facilitates the remarkable low friction and wear properties of articular cartilage in the synovial joints of the body. Lubricin lines the joint surfaces and plays a protective role as a boundary lubricant in sliding contact; decreased expression of lubricin is associated with cartilage degradation and the pathogenesis of osteoarthritis. An unmet need for early osteoarthritis treatment is the development of therapeutic molecules that mimic lubricin function and yet are also resistant to enzymatic degradation common in the damaged joint. Here, we engineered a lubricin mimic (mLub) that is less susceptible to enzymatic degradation and binds to the articular surface to reduce friction. mLub was synthesized using a chondroitin sulfate backbone with type II collagen and hyaluronic acid (HA) binding peptides to promote interaction with the articular surface and synovial fluid constituents. In vitro and in vivo characterization confirmed the binding ability of mLub to isolated type II collagen and HA, and to the cartilage surface. Following trypsin treatment to the cartilage surface, application of mLub, in combination with purified or commercially available hyaluronan, reduced the coefficient of friction, and adhesion, to control levels as assessed over macro-to micro-scales by rheometry and atomic force microscopy. In vivo studies demonstrate an mLub residency time of less than 1 week. Enhanced lubrication by mLub reduces surface friction and adhesion, which may suppress the progression of degradation and cartilage loss in the joint. mLub therefore shows potential for treatment in early osteoarthritis following injury.

  6. Synthesis and characterization of a lubricin mimic (mLub) to reduce friction and adhesion on the articular cartilage surface.

    PubMed

    Lawrence, Alexandra; Xu, Xin; Bible, Melissa D; Calve, Sarah; Neu, Corey P; Panitch, Alyssa

    2015-12-01

    The lubricating proteoglycan, lubricin, facilitates the remarkable low friction and wear properties of articular cartilage in the synovial joints of the body. Lubricin lines the joint surfaces and plays a protective role as a boundary lubricant in sliding contact; decreased expression of lubricin is associated with cartilage degradation and the pathogenesis of osteoarthritis. An unmet need for early osteoarthritis treatment is the development of therapeutic molecules that mimic lubricin function and yet are also resistant to enzymatic degradation common in the damaged joint. Here, we engineered a lubricin mimic (mLub) that is less susceptible to enzymatic degradation and binds to the articular surface to reduce friction. mLub was synthesized using a chondroitin sulfate backbone with type II collagen and hyaluronic acid (HA) binding peptides to promote interaction with the articular surface and synovial fluid constituents. In vitro and in vivo characterization confirmed the binding ability of mLub to isolated type II collagen and HA, and to the cartilage surface. Following trypsin treatment to the cartilage surface, application of mLub, in combination with purified or commercially available hyaluronan, reduced the coefficient of friction, and adhesion, to control levels as assessed over macro-to micro-scales by rheometry and atomic force microscopy. In vivo studies demonstrate an mLub residency time of less than 1 week. Enhanced lubrication by mLub reduces surface friction and adhesion, which may suppress the progression of degradation and cartilage loss in the joint. mLub therefore shows potential for treatment in early osteoarthritis following injury. PMID:26398308

  7. Four unrelated patients with Lubs X-linked mental retardation syndrome and different Xq28 duplications.

    PubMed

    Bartsch, Oliver; Gebauer, Konstanze; Lechno, Stanislav; van Esch, Hilde; Froyen, Guy; Bonin, Michael; Seidel, Jörg; Thamm-Mücke, Barbara; Horn, Denise; Klopocki, Eva; Hertzberg, Christoph; Zechner, Ulrich; Haaf, Thomas

    2010-02-01

    The Lubs X-linked mental retardation syndrome (MRXSL) is caused by small interstitial duplications at distal Xq28 including the MECP2 gene. Here we report on four novel male patients with MRXSL and different Xq28 duplications delineated by microarray-based chromosome analysis. All mothers were healthy carriers of the duplications. Consistent with an earlier report [Bauters et al. (2008); Genome Res 18: 847-858], the distal breakpoints of all four Xq28 duplications were located in regions containing low-copy repeats (LCRs; J, K, and L groups), which may facilitate chromosome breakage and reunion events. The proximal breakpoint regions did not contain known LCRs. Interestingly, we identified apparent recurrent breakage sites in the proximal and distal breakpoint regions. Two of the four patients displayed more complex rearrangements. Patient 2 was endowed with a quadruplicated segment and a small triplication within the duplication, whereas patient 3 displayed two triplicated segments within the duplication, supporting that the Fork Stalling and Template Switching (FoSTeS) model may explain a subset of the structural rearrangements in Xq28. Clinically, muscular hypertonia and contractures of large joints may present a major problem in children with MRXSL. Because injection of botulinum toxin (BT-A; Botox) proved to be extremely helpful for patient 1, we recommend consideration of Botox treatment in other patients with MRXSL and severe joint contractures.

  8. 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-...

  9. Combining UV-C treatment with biocontrol yeast to control postharvest decay of melon.

    PubMed

    Huang, Ke; Zou, Yong; Luo, Jie; Liu, Yiqing

    2015-09-01

    Significant losses in harvested melon can be directly attributable to decay fungi. In the present study, the use of UV-C treatment combined with biocontrol yeast, Pichia cecembensis, was evaluated for their ability to control postharvest decay of melon fruits after they were artificially inoculated with Fusarium oxysporum and Alternaria alternata. Natural infection of fruit was also assessed. As a stand-alone treatment, UV-C or P. cecembensis significantly reduced Fusarium rot and Alternaria rot, and also the level of natural infection on melon fruit, relative to the untreated control. The combination of UV-C or P. cecembensis, however, provided a superior level of decay control on artificially inoculated and naturally infected fruit, compared to either treatment alone. None of the treatments impaired fruit quality. Integrating the use of UV-C treatment with biocontrol yeast has potential as an effective method to control postharvest decay of melon.

  10. Mechanisms of photosynthetic inactivation on growth suppression of Microcystis aeruginosa under UV-C stress.

    PubMed

    Tao, Yi; Mao, Xianzhong; Hu, Jiangyong; Mok, H O L; Wang, Lingyun; Au, D W T; Zhu, Jia; Zhang, Xihui

    2013-10-01

    This study aims to investigate the effects of UV-C irradiation on photosynthetic processes of Microcystis aeruginosa to unravel the mechanism(s) involved in how and in what ways UV-C mediates growth suppression and cellular recovery. Changes in the concentration of photosynthetic pigments, photochemical efficiency, PS II core protein (D1) content, and the coding genes expressions were measured. The results indicate that UV-C doses at 20-200 mJ cm(-2) lead to rapid reduction in gene expression of both psbA (for D1) and cpc (for phycocyanin), but the suppression was short term and recoverable within 3 d of post-UV incubation. Conversely, UV-C doses at ≥50 mJ cm(-2) could induce marked decline in photochemical efficiency (represented by the optimal PS II quantum yield, FV/FM, and the effective PS II quantum yield, Y) as well as decreases in D1 content and water soluble pigments (phycoerythrins, phycocyanins, allophycocyanins) in M. aeruginosa during the post UV-C incubation period. The results suggest that interruption of both the light energy harvesting apparatus (especially the water soluble pigments) and the photochemical process mainly accounted for the growth suppression effect in UV-C irradiated M. aeruginosa. PMID:23838039

  11. [Photosynthetic responses of wheat and pea seedlings to enhanced UV-C radiation and their resistances].

    PubMed

    Li, Xue-Mei; Zhang, Li-Hong; He, Xing-Yuan; Hao, Lin

    2007-03-01

    With wheat and pea seedlings as test materials, this paper studied the effects of UV-C radiation on their leaf photosynthetic characteristics and antioxidant enzyme activities. The results showed that enhanced UV-C radiation could markedly decrease the photosynthetic rate (Pn) , stomatal conductance (Gs), intercellular CO2 concentration (Ci), transpiration rate (Tr) and carboxylation efficiency (CE) of pea leaves, but for wheat leaves, these parameters were increased first and decreased then. Under UV-C condition, the CO2 compensation point of leaf was increased for pea, but decreased first and increased then for wheat. With the increasing duration of UV-C radiation, the antioxidant enzyme activities of both test plants increased first and decreased then, except that the POD activity of pea and SOD activity of wheat decreased gradually. All of these suggested that wheat had a stronger resistance to short-time UV-C radiation than pea, but, with the prolonged duration of UV-C radiation, the photosynthesis and antioxidant enzyme activities of wheat and pea were all decreased.

  12. 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. PMID:27268503

  13. 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.

  14. 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.

  15. 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.

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

    PubMed

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

    2011-11-01

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

  17. 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.

  18. Evidence of physiological phototropin1 (phot1) action in response to UV-C illumination

    PubMed Central

    Magerøy, Melissa Hamner; Kowalik, Erin H; Folta, Kevin M

    2010-01-01

    Stem growth kinetics were measured in cucumber (Cucumis sativus) and Arabidopsis thaliana using highly-sensitive monitoring with 5-minute resolution, in darkness and in response to a short, single pulse of UV-C illumination. The results show that UV-C, like blue light, induces a rapid decrease in seedling growth rate. The fluence-response kinetics and time course were similar to the phototropin1-mediated response observed following a blue pulse. Arabidopsis seedlings were used to assess the genetic mechanism of this response. The phot1 mutant exhibited defects in stem growth rate inhibition, with sustained growth inhibition completely absent following specific treatments. The cryptochrome and phytochrome mutants exhibited responses comparable to wild type, suggesting that these receptor classes do not contribute to this response. The work demonstrates in two species that UV-C has an effect on a rapid plant photomorphogenic response and that the response is partially mediated by the phot1 photoreceptor. PMID:20861684

  19. The Effect of UV-C Exposure on Larval Survival of the Dreissenid Quagga Mussel

    PubMed Central

    Stewart-Malone, Alecia; Misamore, Michael; Wilmoth, Siri; Reyes, Alejandro; Wong, Wai Hing; Gross, Jackson

    2015-01-01

    The rapid spread of quagga mussels (Dreissena rostriformis bugensis) has lead to their invasion of Lake Mead, Nevada, the largest reservoir in North America and partially responsible for providing water to millions of people in the southwest. Current strategies for mitigating the growth and spread of quagga mussels primarily include physical and chemical means of removing adults within water treatment, delivery, and hydropower facilities. In the present study, germicidal ultraviolet light (UV-C) was used to target the larval stage of wild-caught quagga mussel. The lethal effect of UV-C was evaluated at four different doses, 0.0, 13.1, 26.2, and 79.6 mJ/cm2. Tested doses were determined based on results from preliminary trials. The results demonstrate that germicidal UV-C is effective in controlling the free-swimming life history stages of larval quagga mussels. PMID:26186734

  20. Low frequency ultrasound and UV-C for elimination of pathogens in recirculating aquaculture systems.

    PubMed

    Bazyar Lakeh, Amir Abbas; Kloas, Werner; Jung, Rainer; Ariav, Ra'anan; Knopf, Klaus

    2013-09-01

    Low frequency ultrasound (LFUS) was evaluated as a novel disinfection technique within recirculating aquaculture systems both individually and combined with UV-C. Dose-dependent inactivation rates were determined for the total viable counts and model organisms representing different taxa of common fish parasites: the ciliate Paramecium sp., second larval stage (L2) of the nematode Anguillicola crassus and metanauplii of Artemia sp. Application of LFUS up to 19 kJ/L did not reduce the number of colony forming units (CFU), whilst UV-C irradiation was highly effective. Pre-treatment with LFUS reduced the mean size of suspended solids in aquaculture water and thus increased the germicidal effect of UV-C by up to 0.6 log units. LFUS was effective against the eukaryotic organisms, and the dose-dependent inactivation could be well described by functions of an exponential decay. However, the efficiency of LFUS differed greatly between species. A LFUS dose of 1.9 kJ/L (consumed energy) was sufficient to inactivate Artemia by 99%, but a ten times higher dose was necessary to inactivate 95% and 81% of Paramecium and Anguillicola larvae, respectively. In clear water, the energetic efficiency of UV-C (emitted by a low pressure lamp) against Paramecium and Anguillicola larvae was higher compared to LFUS, but LFUS was more efficient against Artemia. However, the efficiency of LFUS against ciliates or nematode larvae would be similar or even higher than UV-C in highly turbid water or if less efficient medium pressure lamps are used. This study shows that LFUS can be applied safely at energy densities that are effective against a wide range of parasites like ciliates, nematodes and crustaceans. The combination of LFUS and UV-C could provide an appropriate water treatment with regards to all relevant pathogens in recirculating aquaculture systems.

  1. 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...

  2. 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 ...

  3. Effectiveness of ultrasound, UV-C, and photocatalysis on inactivation kinetics of Aeromonas hydrophila.

    PubMed

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

    2015-01-01

    In this study, bactericidal effects of 24 kHz ultrasound, ultraviolet (UV-C) irradiation, and titanium dioxide (TiO2) photocatalyst were studied on inactivation of Aeromonas hydrophila, an emerging pathogen listed on the US Environmental Protection Agency's (US EPA) candidate contaminant list. Metabolic activity (using the AlamarBlue dye) assays were performed to assess the residual activity of the microbial cells after the disinfection treatments along with culture-based methods. A faster inactivation rate of 1.52 log min(-1) and inactivation of 7.62 log10 was observed within 5 min of ultrasound exposure. Ultrasound treated cells repaired by 1.4 log10 in contrast to 5.3 log10 repair for UV-C treated cells. Ultrasound treatment significantly lowered the reactivation of Aeromonas hydrophila in comparison to UV-C- and UV-C-induced photocatalysis. Ultrasound appeared to be an effective means of inactivating Aeromonas hydrophila and could be used as a potential disinfection method for water and wastewater reuse.

  4. 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....

  5. 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. PMID:27059814

  6. Blood Group Antigens C, Lub and P1 May Have a Role in HIV Infection in Africans

    PubMed Central

    Motswaledi, Modisa Sekhamo; Kasvosve, Ishmael; Oguntibeju, Oluwafemi Omoniyi

    2016-01-01

    Background Botswana is among the world’s countries with the highest rates of HIV infection. It is not known whether or not this susceptibility to infection is due to genetic factors in the population. Accumulating evidence, however, points to the role of erythrocytes as potential mediators of infection. We therefore sought to establish the role, if any, of some erythrocyte antigens in HIV infection in a cross-section of the population. Methods 348 (346 HIV-negative and 2 HIV-positive) samples were obtained from the National Blood Transfusion Service as residual samples, while 194 HIV-positive samples were obtained from the Botswana-Harvard HIV Reference Laboratory. Samples were grouped for twenty three antigens. Chi-square or Fischer Exact analyses were used to compare the frequencies of the antigens in the two groups. A stepwise, binary logistic regression was used to study the interaction of the various antigens in the light of HIV-status. Results The Rh antigens C and E were associated with HIV-negative status, while blood group Jka, P1 and Lub were associated with HIV-positive status. A stepwise binary logistic regression analysis yielded group C as the most significant protective blood group while Lub and P1 were associated with significantly higher odds ratio in favor of HIV-infection. The lower-risk-associated group C was significantly lower in Africans compared to published data for Caucasians and might partially explain the difference in susceptibility to HIV-1. Conclusion The most influential antigen C, which also appears to be protective, is significantly lower in Africans than published data for Caucasians or Asians. On the other hand, there appear to be multiple antigens associated with increased risk that may override the protective role of C. A study of the distribution of these antigens in other populations may shed light on their roles in the HIV pandemic. PMID:26900853

  7. 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...

  8. 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.

  9. 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...

  10. The effects of sub-lethal UV-C irradiation on growth and cell integrity of cyanobacteria and green algae.

    PubMed

    Tao, Yi; Zhang, Xihui; Au, Doris W T; Mao, Xianzhong; Yuan, Kan

    2010-01-01

    The effects of UV-C irradiation on algal growth and cell integrity were investigated to develop a potential method for preventing cyanobacterial blooms. The toxic cyanobacterium Microcystis aeruginosa and three common freshwater green algae Chlorella ellipsoidea, Chlorella vulgaris, and Scenedesmus quadricanda were exposed to UV-C irradiation at 0-200mJcm(-2) and subsequently incubated for 9-15 d under normal culture conditions. Cell density and cell integrity were assessed using flow cytometry. The results suggested that UV-C irradiation at 20-200mJcm(-2) can suppress M. aeruginosa growth for 3-13 d in a dose-dependent manner. UV-C irradiation at 20 and 50mJcm(-2) is sub-lethal to M. aeruginosa cells as over 80% of the exposed cells remained intact. However, UV-C irradiation at 100 and 200mJcm(-2) induced severe cell disintegration in more than 70% of the irradiated cells. Neither significant suppression nor disintegration effects on green algae were observed for UV-C irradiation at 20-200mJcm(-2) in this study. Taken together, the sensitivity of M. aeruginosa to UV-C irradiation was significantly higher than that of the non-toxic C. ellipsoidea, C. vulgaris, and S. quadricauda, suggesting the potential application of sub-lethal UV-C irradiation for M. aeruginosa bloom control with a predictable low ecological risk. PMID:20005556

  11. 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. PMID:27614243

  12. Fructose Accelerates UV-C Induced Photochemical Degradation of Pentachlorophenol in Low and High Salinity Water.

    PubMed

    Nayak, Shaila; O'Donnell, Sean-Erik; Sales, Christopher M; Tikekar, Rohan V

    2016-06-01

    A novel process involving 254 nm UV-C and fructose to degrade pentachlorophenol (PCP), a pollutant, in low and high salinity (0-10 g/L salt) solutions is presented. The first order rate constants in the presence of 0, 300, and 500 mM fructose were 0.23 ± 0.04, 0.54 ± 0.01, and 1.18 ± 0.03 min(-1), respectively. Experimental evidence has shown generation of hydrogen peroxide and singlet oxygen from the UV-C exposure of fructose, which may have accelerated PCP degradation. Although salts (sodium, potassium, and calcium chloride, 1101:6.4:1) are expected to enhance the degradation rate due to generation of reactive halide species (RHS) from exposure to UV-C light, 10 g/L salt decreased the degradation rates in both the absence and presence of fructose. An LC-ESI-MS spectrum of the reaction mixture revealed a high relative abundance at m/z of 215 that corresponds to a fructose-chlorine adduct, indicating that fructose may have scavenged these RHS and prevented their reaction with PCP.

  13. 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. PMID:16028986

  14. Fructose Accelerates UV-C Induced Photochemical Degradation of Pentachlorophenol in Low and High Salinity Water.

    PubMed

    Nayak, Shaila; O'Donnell, Sean-Erik; Sales, Christopher M; Tikekar, Rohan V

    2016-06-01

    A novel process involving 254 nm UV-C and fructose to degrade pentachlorophenol (PCP), a pollutant, in low and high salinity (0-10 g/L salt) solutions is presented. The first order rate constants in the presence of 0, 300, and 500 mM fructose were 0.23 ± 0.04, 0.54 ± 0.01, and 1.18 ± 0.03 min(-1), respectively. Experimental evidence has shown generation of hydrogen peroxide and singlet oxygen from the UV-C exposure of fructose, which may have accelerated PCP degradation. Although salts (sodium, potassium, and calcium chloride, 1101:6.4:1) are expected to enhance the degradation rate due to generation of reactive halide species (RHS) from exposure to UV-C light, 10 g/L salt decreased the degradation rates in both the absence and presence of fructose. An LC-ESI-MS spectrum of the reaction mixture revealed a high relative abundance at m/z of 215 that corresponds to a fructose-chlorine adduct, indicating that fructose may have scavenged these RHS and prevented their reaction with PCP. PMID:27160945

  15. 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. PMID:27064192

  16. 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.

  17. 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.

  18. 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.

  19. 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. PMID:24679766

  20. 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.

  1. 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.

  2. 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. PMID:23885419

  3. 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.

  4. Use of UV-C postharvest treatment for extending fresh whole tomato (Solanum lycopersicum, cv. Zinac) shelf-life.

    PubMed

    Pinheiro, Joaquina; Alegria, Carla; Abreu, Marta; Gonçalves, Elsa M; Silva, Cristina L M

    2015-08-01

    The effect of UV-C treatments (0.32, 0.97, 2.56, 4.16 and 4.83 kJ.m(-2) at 254 nm) on the physical-chemical properties [colour, texture, total phenolic content (TPC), weight loss (WL)], and mesophylic counts of whole tomato, was evaluated during 15 days at 10 °C. During storage, the Ctr samples acquired faster red colour than all UV-C samples (higher a* and lower °h values). Comparing texture of Ctr and UV-C samples at 15(th) storage day, an increase of 9 and 8 % on firmness of treated samples at low UV-C intensities (0.32 and 0.97 kJ.m(-2), respectively) was observed. At the end of the storage, Ctr samples showed ca. 4 Log10 of mesophylic load, and the samples treated at 0.97 and 4.83 kJ.m(-2) revealed the lowest microbial load (1.9 and 3.2 Log10, respectively). These results indicate that UV-C radiation, at an appropriate dose, combined with low storage temperature (10 °C) are an effective method to preserve the postharvest life of tomato, without adversely affecting quality parameters. PMID:26243927

  5. UV-B light induces an adaptive response to UV-C exposure via photoreactivation activity in Euglena gracilis.

    PubMed

    Takahashi, Akihisa; Shibata, Naoaki; Nishikawa, Shoko; Ohnishi, Ken; Ishioka, Noriaki; Ohnishi, Takeo

    2006-05-01

    Phytoplankton such as Euglena are constantly exposed to solar light which is used for photosynthesis. Although the solar ultraviolet (UV) induces DNA damage such as cyclobutane-pyrimidine dimers (CPDs), many kinds of living organisms can repair CPDs by photoreactivation (PR) utilizing the near-UV/blue light component in sunlight. Euglena cells are known to possess such PR activity. In the present paper, the formation of CPDs induced by UV-C exposure and the photoreactivation PR repair of these CPDs by UV-A are demonstrated. To clarify the adaptive responses prior UV-B irradiation on PR activity, cells were cultured in the dark or under UV-B light. When the cells were cultured in the dark for 3 d prior to UV-C exposure, PR activity decreased. When the cells were cultured under UV-B light, however, PR activity increased. These results suggest that exposing the cells to UV-B prior to exposure to UV-C induced an adaptive response towards DNA damage caused by UV-C exposure, and this UV-C induced damage was repaired through PR activity. PMID:16685323

  6. 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. PMID:26055979

  7. 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.

  8. Resveratrol synthesis under natural conditions and after UV-C irradiation in berry skin is associated with berry development stages in 'Beihong' (V. vinifera×V. amurensis).

    PubMed

    Wang, Jun-Fang; Ma, Ling; Xi, Hui-Fen; Wang, Li-Jun; Li, Shao-Hua

    2015-02-01

    Though UV-C irradiation may induce the synthesis of resveratrol in grape berry skins, it is unclear which developmental stage is most sensitive to UV-C induction. In this study, we investigated resveratrol content and gene expression of 'Beihong' (Vitisvinifera×Vitisamurensis) berries by UV-C irradiation compared with under natural conditions during different developmental stages. Under natural condition, resveratrol synthesis was related to veraison. Before veraison, resveratrol content was very low; however, total resveratrol increased about 500% from veraison to maturity in the main forms of piceids. UV-C irradiation significantly stimulated resveratrol synthesis, mainly in the form of trans-resveratrol. Young berries at 55days after anthesis were most sensitive to UV-C irradiation, the total resveratrol in the skin of UV-C irradiated berry is about 90 times higher than that of the control; however, resveratrol synthesis subsequently declined, which may be attributed to STS regulation by Myb14.

  9. Photodegradation of diphenylarsinic acid by UV-C light: Implication for its remediation.

    PubMed

    Wang, Anan; Teng, Ying; Hu, Xuefeng; Wu, Longhua; Huang, Yujuan; Luo, Yongming; Christie, Peter

    2016-05-01

    Diphenylarsinic acid (DPAA) is a major contaminant in environments polluted by chemical weapons and abandoned after World Wars I and II and poses high risks to biota but remediation methods for this contaminant are rare. Here, the photodegradtion of DPAA was studied under high-pressure Hg lamp irradiation. DPAA was degraded completely into inorganic arsenic species in 30 min under UV-C irradiation. The photodegradation of DPAA depended mainly on its direct photolysis through excited-state DPAA. By contrast, the generation of (1)O2 during the photodegradation of DPAA was confirmed by electron paramagnetic resonance (EPR) studies, but (1)O2 had little effect on the photodegradation of DPAA. Phtotodegradation of DPAA was also studied in soil leachates and groundwater and the photolytic rate of DPAA was controlled by the total organic carbon (TOC) content in soil leachates and by the NO3(-) concentration in groundwater. Finally, studies on the effects of common solutes on the photodegradation of DPAA show that Cl(-) can increase the photolytic rate of DPAA by prolonging the lifetime of excited-state DPAA. Moreover, NO3(-), NO2(-), and humic acid (HA) can decrease the photolytic rate of DPAA by suppressing the production of excited-state DPAA. This research shows the detailed mechanism of DPAA photodegradation and provides a new and effective method for DPAA decontamination. PMID:26835897

  10. The nucleotide excision repair pathway is required for UV-C-induced apoptosis in Caenorhabditis elegans.

    PubMed

    Stergiou, L; Doukoumetzidis, K; Sendoel, A; Hengartner, M O

    2007-06-01

    Ultraviolet (UV) radiation is a mutagen of major clinical importance in humans. UV-induced damage activates multiple signaling pathways, which initiate DNA repair, cell cycle arrest and apoptosis. To better understand these pathways, we studied the responses to UV-C light (254 nm) of germ cells in Caenorhabditis elegans. We found that UV activates the same cellular responses in worms as in mammalian cells. Both UV-induced apoptosis and cell cycle arrest were completely dependent on the p53 homolog CEP-1, the checkpoint proteins HUS-1 and CLK-2, and the checkpoint kinases CHK-2 and ATL-1 (the C. elegans homolog of ataxia telangiectasia and Rad3-related); ATM-1 (ataxia telangiectasia mutated-1) was also required, but only at low irradiation doses. Importantly, mutation of genes encoding nucleotide excision repair pathway components severely disrupted both apoptosis and cell cycle arrest, suggesting that these genes not only participate in repair, but also signal the presence of damage to downstream components of the UV response pathway that we delineate here. Our study suggests that whereas DNA damage response pathways are conserved in metazoans in their general outline, there is significant evolution in the relative importance of individual checkpoint genes in the response to specific types of DNA damage.

  11. Photodegradation of diphenylarsinic acid by UV-C light: Implication for its remediation.

    PubMed

    Wang, Anan; Teng, Ying; Hu, Xuefeng; Wu, Longhua; Huang, Yujuan; Luo, Yongming; Christie, Peter

    2016-05-01

    Diphenylarsinic acid (DPAA) is a major contaminant in environments polluted by chemical weapons and abandoned after World Wars I and II and poses high risks to biota but remediation methods for this contaminant are rare. Here, the photodegradtion of DPAA was studied under high-pressure Hg lamp irradiation. DPAA was degraded completely into inorganic arsenic species in 30 min under UV-C irradiation. The photodegradation of DPAA depended mainly on its direct photolysis through excited-state DPAA. By contrast, the generation of (1)O2 during the photodegradation of DPAA was confirmed by electron paramagnetic resonance (EPR) studies, but (1)O2 had little effect on the photodegradation of DPAA. Phtotodegradation of DPAA was also studied in soil leachates and groundwater and the photolytic rate of DPAA was controlled by the total organic carbon (TOC) content in soil leachates and by the NO3(-) concentration in groundwater. Finally, studies on the effects of common solutes on the photodegradation of DPAA show that Cl(-) can increase the photolytic rate of DPAA by prolonging the lifetime of excited-state DPAA. Moreover, NO3(-), NO2(-), and humic acid (HA) can decrease the photolytic rate of DPAA by suppressing the production of excited-state DPAA. This research shows the detailed mechanism of DPAA photodegradation and provides a new and effective method for DPAA decontamination.

  12. 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...

  13. Antioxidant Defense Mechanisms in Pseudomonas aeruginosa: Role of Iron-Cofactored Superoxide Dismutase in Response to UV-C Radiations.

    PubMed

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

    2016-08-01

    The role of SOD gene in response to UV-C radiations was studied in Pseudomonas aeruginosa. Firstly, our results showed that the inactivation of sodM and/or sodB genes decreases the resistance of P. aeruginosa after exposure to UV-C rays. Furthermore, our results showed that SOD activity is dose dependant in all strains. However, significant increase in SOD activity was only shown at UV-C exposure time of 5 min in sodB mutant. At an elevated dose equivalent to 30 min of exposure, significant increase in SOD activity was observed in sodM. Catalase activities showed significant decrease in WT and in sodB mutant after an exposure time of 30 min. CAT enzyme was present at higher levels than SOD, reflecting that alternate enzymes such as POX, is poorly associated with CAT activity, and an increase in POX activity is related to increase in stress tolerance. The overall results showed that sodB gene has an important protective role against UV-C radiations in P. aeruginosa, compared to SodM isoform. PMID:27094998

  14. Furan formation from fatty acids as a result of storage, gamma irradiation, UV-C and heat treatments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Furan is a possible human carcinogen that has been found in many thermally processed foods. The effects of thermal processing, gamma and UV-C irradiation on formation of furan from different fatty acids was studied. In addition, formation of furan from fatty acid emulsions during storage at 25C and...

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

    PubMed

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

    2016-04-01

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

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

    PubMed

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

    2016-04-01

    Strawberries are available throughout the year either from production in the field or from high and low tunnel culture. Diversity of production conditions results in new challenges in controlling diseases before and after harvest. Fungicides have traditionally been used to control these diseases; however, their limitations necessitate a search for new approaches. We found that UV-C irradiation of Botrytis cinerea, a major pathogen of strawberry, can effectively kill this fungus if a dark period follows the treatment. The inclusion of a 4-h dark period resulted in almost complete kill of B. cinerea conidia on agar media at a dose of 12.36 J/m2. The UV-C dose did not cause a reduction in photosynthesis in strawberry leaves or discoloration of sepals, even after exposing plants repeatedly (twice a week) for 7 weeks. Although irradiation of dry conidia of B. cinerea with this dose resulted in some survival, the conidia were not infective and not able to cause decay even when inoculated onto a highly susceptible mature apple fruit. Irradiation of strawberry pollen at 12.36 J/m2 did not affect pollen germination, tube growth and length in vitro, or germination and tube growth in the style of hand-pollinated emasculated strawberry flowers. No negative effect of the UV-C treatment was observed on fruit yield and quality in high tunnel culture. In the fruit and flower petal inoculation tests, the UV-C treatment was highly effective in reducing fruit decay and petal infection. This UV-C treatment with an exposure time of 60 s may be useful in controlling gray mold in tunnel production of strawberries and may also have the potential for use in intensive field and indoor production of other fruits and vegetables providing that a 4-h dark period follows the irradiation. PMID:26714103

  17. Current spreading in UV-C LEDs emitting at 235 nm

    NASA Astrophysics Data System (ADS)

    Lapeyrade, Mickael; Eberspach, Florian; Glaab, Johannes; Lobo-Ploch, Neysha; Reich, Christoph; Kuhn, Christian; Guttmann, Martin; Wernicke, Tim; Mehnke, Frank; Einfeldt, Sven; Knauer, Arne; Weyers, Markus; Kneissl, Michael

    2015-03-01

    We present UV-C LEDs emitting around 235 nm grown by MOVPE on ELO AlN/sapphire substrates. In order to account for the low conductivity of high Al content AlGaN layers and the associated high contact resistances, we designed an optimized compact LED geometry based on electro-thermal simulations of the current spreading. Experimental data (layer and contact resistances) are collected on test structures and used as input parameters for 3-D current spreading simulations. With resistances of the layers (n and p) approaching 0.1 Ωcm, the use of a segmented p-area with broad n-contact fingers (10 μm or more) that are close to the mesa edge (5 μm) help to maximize the emission power in the center of the structure. Based on this knowledge a series of compact LEDs of size 500 μm x 500 μm is designed and simulated. We get confirmation that the segmentation of the p-area is the most critical parameter to limit the non-uniformity introduced by the high n-sheet resistances. Up to 17% in emission power can be gained when the n-contacts are designed properly. LEDs with the optimum geometry were processed and measured. We get a good confirmation of our model concerning the distribution of the emission power. Both simulations and measurements show current crowding at the edge of the n-contact, however the power loss in the middle of the chip is higher than predicted.

  18. Study of leaf metabolome modifications induced by UV-C radiations in representative Vitis, Cissus and Cannabis species by LC-MS based metabolomics and antioxidant assays.

    PubMed

    Marti, Guillaume; Schnee, Sylvain; Andrey, Yannis; Simoes-Pires, Claudia; Carrupt, Pierre-Alain; Wolfender, Jean-Luc; Gindro, Katia

    2014-09-05

    UV-C radiation is known to induce metabolic modifications in plants, particularly to secondary metabolite biosynthesis. To assess these modifications from a global and untargeted perspective, the effects of the UV-C radiation of the leaves of three different model plant species, Cissus antarctica Vent. (Vitaceae), Vitis vinifera L. (Vitaceae) and Cannabis sativa L. (Cannabaceae), were evaluated by an LC-HRMS-based metabolomic approach. The approach enabled the detection of significant metabolite modifications in the three species studied. For all species, clear modifications of phenylpropanoid metabolism were detected that led to an increased level of stilbene derivatives. Interestingly, resveratrol and piceid levels were strongly induced by the UV-C treatment of C. antarctica leaves. In contrast, both flavonoids and stilbene polymers were upregulated in UV-C-treated Vitis leaves. In Cannabis, important changes in cinnamic acid amides and stilbene-related compounds were also detected. Overall, our results highlighted phytoalexin induction upon UV-C radiation. To evaluate whether UV-C stress radiation could enhance the biosynthesis of bioactive compounds, the antioxidant activity of extracts from control and UV-C-treated leaves was measured. The results showed increased antioxidant activity in UV-C-treated V. vinifera extracts.

  19. The antibacterial activity of a microwave argon plasma jet at atmospheric pressure relies mainly on UV-C radiations

    NASA Astrophysics Data System (ADS)

    Judée, F.; Wattieaux, G.; Merbahi, N.; Mansour, M.; Castanié-Cornet, M. P.

    2014-10-01

    The main bactericidal sources produced by a microwave induced cold argon plasma jet in open air are identified and their relative proportion in the biocide efficiency of the jet is assessed on planktonic Gram-negative bacteria (wild-type strains and deletion mutants of Escherichia coli) diluted in water. In these conditions ultraviolet light (UV) most probably in the UV-C region of the electromagnetic spectrum, is responsible for 86.7 ± 3.2% of the observed bactericidal efficiency of the jet whereas hydrogen peroxide represents 9.9 ± 5.5% of it. The exposition level of the bacteria to UV-C radiations is estimated at 20 mJ cm-2 using a specific photodiode and the influence of the initial bacteria concentration on the apparent antibacterial efficiency of the jet is highlighted.

  20. 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. PMID:25133899

  1. 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.

  2. Experimental Evolution of UV-C Radiation Tolerance: Emergence of Adaptive and Non-Adaptive Traits in Escherichia coli Under Differing Flux Regimes

    NASA Astrophysics Data System (ADS)

    Moffet, A.; Okansinski, A.; Sloan, C.; Grace, J. M.; Paulino-Lima, I. G.; Gentry, D.; Rothschild, L. J.; Camps, M.

    2014-12-01

    High-energy ultraviolet (UV-C) radiation is a significant challenge to life in environments such as high altitude areas, the early Earth, the Martian surface, and space. As UV-C exposure is both a selection pressure and a mutagen, adaptation dynamics in such environments include a high rate of change in both tolerance-related and non-tolerance-related genes, as well changes in linkages between the resulting traits. Determining the relationship between the intensity and duration of the UV-C exposure, mutation rate, and emergence of UV-C resistance will inform our understanding of both the emergence of radiation-related extremophily in natural environments and the optimal strategies for generating artificial extremophiles. In this study, we iteratively exposed an Escherichia colistrain to UV-C radiation of two different fluxes, 3.3 J/m^2/s for 6 seconds and 0.5 J/m^2/s for 40 seconds, with the same overall fluence of 20 J/m^2. After each iteration, cells from each exposure regime were assayed for increased UV-C tolerance as an adaptive trait. The exposed cells carried a plasmid bearing a TEM beta-lactamase gene, which in the absence of antibiotic treatment is a neutral reporter for mutagenesis. Sequencing of this gene allowed us to determine the baseline mutation frequency for each flux. As an additional readout for adaptation, the presence of extended-spectrum beta-lactamase mutations was tested by plating UV-exposed cultures in cefotaxime plates. We observed an increase of approximately one-million-fold in UV-C tolerance over seven iterations; no significant difference between the two fluxes was found. Future work will focus on identifying the genomic changes responsible for the change in UV-C tolerance; determining the mechanisms of the emerged UV-C tolerance; and performing competition experiments between the iteration strains to quantify fitness tradeoffs resulting from UV-C adaptation.

  3. 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.

  4. Induced carotenoid accumulation in Dunaliella salina and Tetraselmis suecica by plant hormones and UV-C radiation.

    PubMed

    Ahmed, Faruq; Fanning, Kent; Netzel, Michael; Schenk, Peer M

    2015-11-01

    Carotenoids prevent different degenerative diseases and improve human health. Microalgae are commercially exploited for carotenoids, including astaxanthin and β-carotene. Two commercially important microalgae, Dunaliella salina and Tetraselmis suecica, were treated with plant hormones salicylic acid (SA) and methyl jasmonate (MJ), or by UV-C radiation (T. suecica only) and a combination thereof. Significant increases in total carotenoids were found for D. salina and T. suecica after treatment with MJ (10 μmol/L) and SA (70-250 μmol/L), respectively. T. suecica also had significant increases in total carotenoids following UV-C radiation compared to control cultures. Among the carotenoids, lutein was the highest induced carotenoid. A combination of these two treatments also showed a significant increase in total carotenoids and lutein for T. suecica, when compared to controls. Plant hormones and UV-C radiation may be useful tools for increasing carotenoid accumulation in green microalgae although the responses are species- and dose-specific and should be trialed in medium to large scale to explore commercial production. PMID:26201492

  5. Induced carotenoid accumulation in Dunaliella salina and Tetraselmis suecica by plant hormones and UV-C radiation.

    PubMed

    Ahmed, Faruq; Fanning, Kent; Netzel, Michael; Schenk, Peer M

    2015-11-01

    Carotenoids prevent different degenerative diseases and improve human health. Microalgae are commercially exploited for carotenoids, including astaxanthin and β-carotene. Two commercially important microalgae, Dunaliella salina and Tetraselmis suecica, were treated with plant hormones salicylic acid (SA) and methyl jasmonate (MJ), or by UV-C radiation (T. suecica only) and a combination thereof. Significant increases in total carotenoids were found for D. salina and T. suecica after treatment with MJ (10 μmol/L) and SA (70-250 μmol/L), respectively. T. suecica also had significant increases in total carotenoids following UV-C radiation compared to control cultures. Among the carotenoids, lutein was the highest induced carotenoid. A combination of these two treatments also showed a significant increase in total carotenoids and lutein for T. suecica, when compared to controls. Plant hormones and UV-C radiation may be useful tools for increasing carotenoid accumulation in green microalgae although the responses are species- and dose-specific and should be trialed in medium to large scale to explore commercial production.

  6. 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. PMID:27666295

  7. 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.

  8. Mutation of Arabidopsis HY1 causes UV-C hypersensitivity by impairing carotenoid and flavonoid biosynthesis and the down-regulation of antioxidant defence.

    PubMed

    Xie, Yanjie; Xu, Daokun; Cui, Weiti; Shen, Wenbiao

    2012-06-01

    Previous pharmacological results confirmed that haem oxygenase-1 (HO-1) is involved in protection of cells against ultraviolet (UV)-induced oxidative damage in soybean [Glycine max (L.) Merr.] seedlings, but there remains a lack of genetic evidence. In this study, the link between Arabidopsis thaliana HO-1 (HY1) and UV-C tolerance was investigated at the genetic and molecular levels. The maximum inducible expression of HY1 in wild-type Arabidopsis was observed following UV-C irradiation. UV-C sensitivity was not observed in ho2, ho3, and ho4 single and double mutants. However, the HY1 mutant exhibited UV-C hypersensitivity, consistent with the observed decreases in chlorophyll content, and carotenoid and flavonoid metabolism, as well as the down-regulation of antioxidant defences, thereby resulting in severe oxidative damage. The addition of the carbon monoxide donor carbon monoxide-releasing molecule-2 (CORM-2), in particular, and bilirubin (BR), two catalytic by-products of HY1, partially rescued the UV-C hypersensitivity, and other responses appeared in the hy1 mutant. Transcription factors involved in the synthesis of flavonoid or UV responses were induced by UV-C, but reduced in the hy1 mutant. Overall, the findings showed that mutation of HY1 triggered UV-C hypersensitivity, by impairing carotenoid and flavonoid synthesis and antioxidant defences.

  9. Mutation of Arabidopsis HY1 causes UV-C hypersensitivity by impairing carotenoid and flavonoid biosynthesis and the down-regulation of antioxidant defence

    PubMed Central

    Xie, Yanjie; Xu, Daokun; Cui, Weiti; Shen, Wenbiao

    2012-01-01

    Previous pharmacological results confirmed that haem oxygenase-1 (HO-1) is involved in protection of cells against ultraviolet (UV)-induced oxidative damage in soybean [Glycine max (L.) Merr.] seedlings, but there remains a lack of genetic evidence. In this study, the link between Arabidopsis thaliana HO-1 (HY1) and UV-C tolerance was investigated at the genetic and molecular levels. The maximum inducible expression of HY1 in wild-type Arabidopsis was observed following UV-C irradiation. UV-C sensitivity was not observed in ho2, ho3, and ho4 single and double mutants. However, the HY1 mutant exhibited UV-C hypersensitivity, consistent with the observed decreases in chlorophyll content, and carotenoid and flavonoid metabolism, as well as the down-regulation of antioxidant defences, thereby resulting in severe oxidative damage. The addition of the carbon monoxide donor carbon monoxide-releasing molecule-2 (CORM-2), in particular, and bilirubin (BR), two catalytic by-products of HY1, partially rescued the UV-C hypersensitivity, and other responses appeared in the hy1 mutant. Transcription factors involved in the synthesis of flavonoid or UV responses were induced by UV-C, but reduced in the hy1 mutant. Overall, the findings showed that mutation of HY1 triggered UV-C hypersensitivity, by impairing carotenoid and flavonoid synthesis and antioxidant defences. PMID:22419743

  10. 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.

  11. Extreme tolerance and developmental buffering of UV-C induced DNA damage in embryos of the annual killifish Austrofundulus limnaeus.

    PubMed

    Wagner, Josiah T; Podrabsky, Jason E

    2015-01-01

    Free-living aquatic embryos are often at risk of exposure to ultraviolet radiation (UV-R). Successful completion of embryonic development depends on efficient removal of DNA lesions, and thus many aquatic embryos have mechanisms to reverse DNA lesions induced by UV-R. However, little is known of how embryos that are able to enter embryonic dormancy may respond to UV-R exposure and subsequent DNA damage. Embryos of the annual killifish Austrofundulus limnaeus are unique among vertebrates because their normal embryonic development includes (1) a complete dispersion of embryonic blastomeres prior to formation of the definitive embryonic axis, and (2) entry into a state of metabolic depression and developmental arrest termed diapause. Here, we show that developing and diapausing embryos of A. limnaeus have exceptional tolerance of UV-C radiation and can successfully complete embryonic development after receiving substantial doses of UV-C, especially if allowed to recover in full-spectrum light. Recovery in full-spectrum light permits efficient removal of the most common type of DNA lesion induced by UV-R: cyclobutane pyrimidine dimers. Interestingly, whole-mount embryo TUNEL assays suggest that apoptosis may not be a major contributor to cell death in embryos UV-C irradiated during dispersion/reaggregation or diapause. We also observed embryo mortality to be significantly delayed by several weeks in diapausing embryos irradiated and allowed to recover in the dark. These atypical responses to UV-R induced DNA damage may be due to the unique annual killifish life history and provide insight into DNA damage repair and recognition mechanisms during embryonic dormancy.

  12. 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.

  13. Short-term UV-B and UV-C radiations preferentially decrease spermidine contents and arginine decarboxylase transcript levels of Synechocystis sp. PCC 6803.

    PubMed

    Jantaro, Saowarath; Pothipongsa, Apiradee; Khanthasuwan, Suparaporn; Incharoensakdi, Aran

    2011-02-01

    To investigate the short term effect of ultraviolet (UV) radiations on changes in pigments and polyamine contents, Synechocystis sp. PCC 6803 cells after exposure to UV-radiation were extracted by dimethylformamide and perchloric acid for pigments and polyamines determination, respectively. Cell growth was slightly decreased after 1 h exposure to UV-A and UV-B radiations. UV-C had little effect on cell growth despite the decrease of photosynthetic rate by about 18%. UV-A and UV-B decreased the contents of chlorophyll a and carotenoids whereas UV-C decreased chlorophyll a but had no effect on carotenoids. Spermidine contents were unaffected by UV-A, in contrast to the reduction of 25 and 50% by UV-B and UV-C, respectively. All three types of UV-radiation particularly reduced perchloric acid-insoluble spermidine. Importantly, putrescine and spermine which accounted for less than 1% of intracellular polyamines were increased by about three- to eight-fold by UV-B and UV-C, respectively. The changes in polyamines contents by UV-B and UV-C were consistent with the changes in transcript levels of arginine decarboxylase mRNA, but not with the protein levels. The decrease in the transcripts of adc2 but not adc1 was observed with UV-B and UV-C treatments.

  14. 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. PMID:25884367

  15. Transgenerational changes in plant physiology and in transposon expression in response to UV-C stress in Arabidopsis thaliana.

    PubMed

    Migicovsky, Zoe; Kovalchuk, Igor

    2014-01-01

    Stress has a negative impact on crop yield by altering a gain in biomass and affecting seed set. Recent reports suggest that exposure to stress also influences the response of the progeny. In this paper, we analyzed seed size, leaf size, bolting time and transposon expression in 2 consecutive generations of Arabidopsis thaliana plants exposed to moderate UV-C stress. Since previous reports suggested a potential role of Dicer-like (DCL) proteins in the establishment of transgenerational response, we used dcl2, dcl3 and dcl4 mutants in parallel with wild-type plants. These studies revealed that leaf number decreased in the progeny of UV-C stressed plants, and bolting occurred later. Transposons were also re-activated in the progeny of stressed plants. Changes in the dcl mutants were less prominent than in wild-type plants. DCL2 and DCL3 appeared to be more important in the transgenerational stress memory than DCL4 because transgenerational changes were less profound in the dcl2 and dcl3 mutants.

  16. Efficacy of UV-C photolysis of bisphenol A on transcriptome alterations of genes in zebrafish embryos.

    PubMed

    Saeed, Asma; Hashmi, Imran; Zare, Ava; Mehrabani-Zeinabad, Mitra; Achari, Gopal; Habibi, Hamid R

    2016-09-18

    The purpose of this study was to investigate the efficacy of UV-C direct photolysis of bisphenol A (BPA) as a remediation method of BPA contamination. We used zebrafish embryos as a model organism to test the toxicity and residual biological activity by measuring cytochrome P4501A1 (CYP1A), aromatase B (Aro B) and heat shock proteins (HSP-70) transcript levels. The mRNA levels of CYP1A gene increased about two fold while exposure of zebrafish embryos at 72 hpf resulted in significant induction (P = 0.048) of Aro B at 100 µg/L of BPA. Exposure of zebrafish embryos at 72 hpf to increasing concentrations of BPA resulted in significant induction (P = 0.0031) of HSP-70 transcript level. UV treatment of BPA resulted in a significant reduction in toxicity by reducing mortality of zebrafish embryos. The results suggest that UV-C direct photolysis may be an effective method for remediation of BPA contamination. Further studies will be necessary for better understanding of the identity and relative activity of the UV degradation by-products. PMID:27314163

  17. 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.

  18. Furan formation from fatty acids as a result of storage, gamma irradiation, UV-C and heat treatments.

    PubMed

    Fan, Xuetong

    2015-05-15

    The effects of gamma and UV-C irradiation in comparison with thermal processing and storage at 25°C on formation of furan from different fatty acids were investigated. Results showed that furan was generated from polyunsaturated fatty acids such as linoleic and linolenic acid during thermal (120°C, 25 min) and UV-C (11.5 J/cm(2)) treatments. Gamma irradiation (up to 20 kGy) did not induce formation of significant amounts of furan from any of the fatty acids studied. Storage of unsaturated fatty acid emulsions at 25°C for 3 days led to the formation of furan (7-11 ng/mL) even without prior thermal or non-thermal treatments. pH significantly impacted furan formation with >3.5 times more furan formed at pH 9 than at pHs 3 or 6 during 3 days at 25°C. The addition of Trolox, BHA, and propyl gallate had no significant effect on furan formation from linolenic acid while α-tocopherol and FeSO4 promoted furan formation.

  19. Simultaneous Observation of Cells and Nuclear Tracks from the Boron Neutron Capture Reaction by UV-C Sensitization of Polycarbonate.

    PubMed

    Portu, Agustina; Rossini, Andrés Eugenio; Thorp, Silvia Inés; Curotto, Paula; Pozzi, Emiliano César Cayetano; Granell, Pablo; Golmar, Federico; Cabrini, Rómulo Luis; Martin, Gisela Saint

    2015-08-01

    The distribution of boron in tissue samples coming from boron neutron capture therapy protocols can be determined through the analysis of its autoradiography image on a nuclear track detector. A more precise knowledge of boron atom location on the microscopic scale can be attained by the observation of nuclear tracks superimposed on the sample image on the detector. A method to produce an "imprint" of cells cultivated on a polycarbonate detector was developed, based on the photodegradation properties of UV-C radiation on this material. Optimal conditions to generate an appropriate monolayer of Mel-J cells incubated with boronophenylalanine were found. The best images of both cells and nuclear tracks were obtained for a neutron fluence of 1013 cm-2, 6 h UV-C (254 nm) exposure, and 4 min etching time with a KOH solution. The imprint morphology was analyzed by both light and scanning electron microscopy. Similar samples, exposed to UV-A (360 nm) revealed no cellular imprinting. Etch pits were present only inside the cell imprints, indicating a preferential boron uptake (about threefold the incubation concentration). Comparative studies of boron absorption in different cell lines and in vitro evaluation of the effect of diverse boron compounds are feasible with this methodology. PMID:26155721

  20. Simultaneous Observation of Cells and Nuclear Tracks from the Boron Neutron Capture Reaction by UV-C Sensitization of Polycarbonate.

    PubMed

    Portu, Agustina; Rossini, Andrés Eugenio; Thorp, Silvia Inés; Curotto, Paula; Pozzi, Emiliano César Cayetano; Granell, Pablo; Golmar, Federico; Cabrini, Rómulo Luis; Martin, Gisela Saint

    2015-08-01

    The distribution of boron in tissue samples coming from boron neutron capture therapy protocols can be determined through the analysis of its autoradiography image on a nuclear track detector. A more precise knowledge of boron atom location on the microscopic scale can be attained by the observation of nuclear tracks superimposed on the sample image on the detector. A method to produce an "imprint" of cells cultivated on a polycarbonate detector was developed, based on the photodegradation properties of UV-C radiation on this material. Optimal conditions to generate an appropriate monolayer of Mel-J cells incubated with boronophenylalanine were found. The best images of both cells and nuclear tracks were obtained for a neutron fluence of 1013 cm-2, 6 h UV-C (254 nm) exposure, and 4 min etching time with a KOH solution. The imprint morphology was analyzed by both light and scanning electron microscopy. Similar samples, exposed to UV-A (360 nm) revealed no cellular imprinting. Etch pits were present only inside the cell imprints, indicating a preferential boron uptake (about threefold the incubation concentration). Comparative studies of boron absorption in different cell lines and in vitro evaluation of the effect of diverse boron compounds are feasible with this methodology.

  1. 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.

  2. Postharvest stilbene-enrichment of red and white table grape varieties using UV-C irradiation pulses.

    PubMed

    Cantos, Emma; Espín, Juan Carlos; Tomás-Barberán, Francisco A

    2002-10-23

    The red table grape varieties Flame, Red Globe, Crimson, and Napoleon, as well as the white varieties Superior, Dominga, and Moscatel Italica, were irradiated with a previously optimized UV-C postharvest irradiation protocol (510 W, 40 cm, 60 s). The induction kinetics of the stilbenes trans-resveratrol, trans-piceid, trans-piceatannol, trans-astringin, and viniferins was followed by using HPLC-DAD/MS/MS. The most inducible stilbenes were trans-resveratrol, trans-piceatannol, and viniferins. Both quantitative and qualitative differences were observed in both the stilbene induction kinetics and stilbene content in the seven table grapes analyzed here. The total resveratrol content ranged from 0.69 mg/100 g fw (Dominga) to 2.3 mg/100 g fw (Red Globe). The net resveratrol induction ranged from 3.4-fold (Flame) to 2315-fold (Red Globe). The highest viniferins content was observed in the variety Flame (0.73 mg/100 g fw), although the variety Red Globe presented the highest viniferins induction (175-fold). The highest content and induction of piceatannol (0.17 mg/100 g fw and 173-fold, respectively) was observed in the variety Flame. It should be stressed that taking into account the health-beneficial effects claimed for stilbenes, the UV-C irradiated table grapes can be considered as new functional fruits that can supply (a serving of unpeeled 200 g table grapes) the resveratrol content (depending on the variety) equivalent to more than seven glasses of red wine ( approximately 1.5 L) with high resveratrol content. PMID:12381111

  3. 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.

  4. 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. PMID:27211630

  5. Effect of UV-C irradiation and low temperature storage on bioactive compounds, antioxidant enzymes and radical scavenging activity of papaya fruit.

    PubMed

    Rivera-Pastrana, Dulce M; Gardea, Alfonso A; Yahia, Elhadi M; Martínez-Téllez, Miguel A; González-Aguilar, Gustavo A

    2014-12-01

    Mature green 'Maradol' papaya fruits were exposed to ultraviolet (UV)-C irradiation (1.48 kJ·m(-2)) and stored at 5 or 14 °C. Changes in total phenols, total flavonoids, enzymatic activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD), as well as the scavenging activity against 2,2-diphenyl-1picrylhydrazyl (DPPH) and 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radicals were investigated in peel and flesh tissues at 0, 5, 10 and 15 days of storage. UV-C irradiation increased significantly (P < 0.05) the flavonoid content (2.5 and 26 %) and ABTS radical scavenging activity (5.7 and 6 %) in flesh and peel at 14 °C respectively; and CAT activity (16.7 %) in flesh at 5 °C. Flavonoid contents, CAT and SOD activities were positively affected under low storage temperature (5 °C). DPPH and ABTS radical scavenging activities increased in both control and UV-C treated papaya peel during storage at 5 °C. UV-C irradiation effect on radical scavenging of papaya peel could be attributed to increased flavonoid content. Papaya antioxidant system was activated by UV-C and cold storage by increasing phenolic content and antioxidant enzymatic activities as a defense response against oxidative-stress. PMID:25477649

  6. Effects of UV-C irradiation on phosphoinositide turnover in plant cells: similarities with those occurring via the formation of reactive oxygen intermediates in animal cells.

    PubMed

    Piacentini, M P; Ricci, D; Fraternale, D; Piatti, E; Manunta, A; Accorsi, A

    1999-03-01

    With the aim of examining the response of plant cells to UV-C irradiation, we investigated the behaviour of the phosphatidylinositol 4,5 bisphosphate (PtdIns 4,5-P2) molecule (the precursor of the phosphoinositide signal transduction cascade) by exposing callus cells from Peucedanum verticillare to UV-C (130 J m-2) and by examining the level and the fatty acid composition of PtdIns 4,5-P2 at different times after irradiation. We show that a pathway for the UV-C response includes transient PtdIns 4,5-P2 breakdown. The effect of ultraviolet rays is mimicked by H2O2 suggesting that in this plant it may be brought about by reactive oxygen intermediates (ROI), as already underlined in experimental animal models. PMID:10374257

  7. 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.

  8. 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.

  9. 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.

  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. PMID:23276426

  11. Mitotic genes are transcriptionally upregulated in the fibroblast irradiated with very low doses of UV-C

    PubMed Central

    Takeuchi, Seiji; Matsuda, Toshiro; Ono, Ryusuke; Tsujimoto, Mariko; Nishigori, Chikako

    2016-01-01

    Ultraviolet (UV) radiation induces a variety of biological effects, including DNA damage response and cell signaling pathways. We performed transcriptome analysis using microarray in human primary cultured fibroblasts irradiated with UV-C (0.5 or 5 J/m2) and harvested at 4 or 12 h following UV exposure. All transcript data were analyzed by comparison with the corresponding results in non-irradiated (control) cells. The number of genes with significantly altered expression (≥2-fold difference relative to the control) is higher in the sample irradiated with high dose of UV, suggesting that gene expression was UV dose-dependent. Pathway analysis on the upregulated genes at 12 h indicates that the expression of some cell cycle-related genes was predominantly induced irrespective of UV-dose. Interestingly, almost all the genes with significant altered expression were cell cycle-related genes designated as ‘Mitotic Genes’, which function in the spindle assembly checkpoint. Therefore, even a low dose of UV could affect the transcriptional profile. PMID:27378355

  12. 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.

  13. 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...

  14. 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

  15. 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...

  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. Lesion simulating disease 1 and enhanced disease susceptibility 1 differentially regulate UV-C-induced photooxidative stress signalling and programmed cell death in Arabidopsis thaliana.

    PubMed

    Wituszyńska, Weronika; Szechyńska-Hebda, Magdalena; Sobczak, Mirosław; Rusaczonek, Anna; Kozłowska-Makulska, Anna; Witoń, Damian; Karpiński, Stanisław

    2015-02-01

    As obligate photoautotrophs, plants are inevitably exposed to ultraviolet (UV) radiation. Because of stratospheric ozone depletion, UV has become more and more dangerous to the biosphere. Therefore, it is important to understand UV perception and signal transduction in plants. In the present study, we show that lesion simulating disease 1 (LSD1) and enhanced disease susceptibility 1 (EDS1) are antagonistic regulators of UV-C-induced programmed cell death (PCD) in Arabidopsis thaliana. This regulatory dependence is manifested by a complex deregulation of photosynthesis, reactive oxygen species homeostasis, antioxidative enzyme activity and UV-responsive genes expression. We also prove that a UV-C radiation episode triggers apoptotic-like morphological changes within the mesophyll cells. Interestingly, chloroplasts are the first organelles that show features of UV-C-induced damage, which may indicate their primary role in PCD development. Moreover, we show that Arabidopsis Bax inhibitor 1 (AtBI1), which has been described as a negative regulator of plant PCD, is involved in LSD1-dependent cell death in response to UV-C. Our results imply that LSD1 and EDS1 regulate processes extinguishing excessive energy, reactive oxygen species formation and subsequent PCD in response to different stresses related to impaired electron transport.

  18. 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...

  19. Lesion simulating disease 1 and enhanced disease susceptibility 1 differentially regulate UV-C-induced photooxidative stress signalling and programmed cell death in Arabidopsis thaliana.

    PubMed

    Wituszyńska, Weronika; Szechyńska-Hebda, Magdalena; Sobczak, Mirosław; Rusaczonek, Anna; Kozłowska-Makulska, Anna; Witoń, Damian; Karpiński, Stanisław

    2015-02-01

    As obligate photoautotrophs, plants are inevitably exposed to ultraviolet (UV) radiation. Because of stratospheric ozone depletion, UV has become more and more dangerous to the biosphere. Therefore, it is important to understand UV perception and signal transduction in plants. In the present study, we show that lesion simulating disease 1 (LSD1) and enhanced disease susceptibility 1 (EDS1) are antagonistic regulators of UV-C-induced programmed cell death (PCD) in Arabidopsis thaliana. This regulatory dependence is manifested by a complex deregulation of photosynthesis, reactive oxygen species homeostasis, antioxidative enzyme activity and UV-responsive genes expression. We also prove that a UV-C radiation episode triggers apoptotic-like morphological changes within the mesophyll cells. Interestingly, chloroplasts are the first organelles that show features of UV-C-induced damage, which may indicate their primary role in PCD development. Moreover, we show that Arabidopsis Bax inhibitor 1 (AtBI1), which has been described as a negative regulator of plant PCD, is involved in LSD1-dependent cell death in response to UV-C. Our results imply that LSD1 and EDS1 regulate processes extinguishing excessive energy, reactive oxygen species formation and subsequent PCD in response to different stresses related to impaired electron transport. PMID:24471507

  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. Advanced oxidation of the commercial nonionic surfactant octylphenol polyethoxylate Triton™ X-45 by the persulfate/UV-C process: effect of operating parameters and kinetic evaluation

    PubMed Central

    Arslan-Alaton, Idil; Olmez-Hanci, Tugba; Genç, Bora; Dursun, Duygu

    2013-01-01

    This study explored the potential use of a sulfate radical (SO·−4)-based photochemical oxidation process to treat the commercial nonionic surfactant octylphenol polyethoxylate (OPPE) Triton™ X-45. For this purpose, the effect of initial S2O2−8 (0–5.0 mM) and OPPE (10–100 mg/L) concentrations on OPPE and its organic carbon content (TOC) removal were investigated at an initial reaction pH of 6.5. Results indicated that very fast OPPE degradation (100%) accompanied with high TOC abatement rates (90%) could be achieved for 10 and 20 mg/L aqueous OPPE at elevated S2O2−8 concentrations (≥2.5 mM). S2O2−8/UV-C treatment was still capable of complete OPPE removal up to an initial concentration of 40 mg/L in the presence of 2.5 mM S2O2−8. On the other hand, TOC removal efficiencies dropped down to only 40% under the same reaction conditions. S2O2−8/UV-C oxidation of OPPE was also compared with the relatively well-known and established H2O2/UV-C oxidation process. Treatment results showed that the performance of S2O2−8/UV-C was comparable to that of H2O2/UV-C oxidation for the degradation and mineralization of OPPE. In order to elucidate the relative reactivity and selectivity of SO·−4 and HO·, bimolecular reaction rate coefficients of OPPE with SO·−4 and HO· were determined by employing competition kinetics with aqueous phenol (47 μM) selected as the reference compound. The pseudo-first-order abatement rate coefficient obtained for OPPE during S2O2−8/UV-C oxidation (0.044 min−1) was found to be significantly lower than that calculated for phenol (0.397 min−1). In the case of H2O2/UV-C oxidation however, similar pseudo-first-order abatement rate coefficients were obtained for both OPPE (0.087 min−1) and phenol (0.140 min−1). From the kinetic study, second-order reaction rate coefficients for OPPE with SO·−4 and HO· were determined as 9.8 × 108 M−1 s−1 and 4.1 × 109 M−1 s−1, respectively. The kinetic study also revealed

  2. Modification of plasma membrane electron transport in cultured rose cells by UV-C radiation and fungal elicitor

    SciTech Connect

    Murphy, T.M.; Auh, C.K.; Schorr, R.; Grobe, C. )

    1991-05-01

    Previous experiments have shown that treatments of suspension-cultured cells of Rosa damascena Mill. with UV radiation or with fungal elicitors stimulates the synthesis of H{sub 2}O{sub 2} by the cells. To test the hypothesis that this synthesis involves reduction of O{sub 2} at the plasma membrane and to identify the mechanism of the reduction, we have determined the effects of UV and elicitor on redox reactions associated with the plasma membrane. Elicitor prepared from cell walls of Phytophthora sp. (14 {mu}g solids/ml) inhibited the reduction of ferricyanide by intact cells by 98%; UV-C (primarily 254 nm, up to 19,500 J/m{sup 2}) inhibited this reduction by 40%. Neither treatment inhibited the reduction of Fe(III)-EDTA by intact cells. Intact cells oxidized NADH in the absence of external oxidizing agent, and the rate of oxidation was increased by UV and elicitor. Cells that were poisoned with arsenite and CCCP catalyzed the reduction of Fe(III)-EDTA in the presence of external NADH, and this ability was slightly stimulated by UV and elicitor. UV irradiation (6,480 J/m{sup 2}) of cells resulted in a 27% inhibition of the specific activity of NADH-ferricyanide oxidoreductase in plasma membrane isolated from those cells. Elicitor treatment of cells for at least 90 min resulted in a 50% inhibition of the enzyme's specific activity in isolated plasma membrane; this inhibition was reversed by addition of Triton-X100 in the assay mixture. The results suggest that UV and elicitor alter the flow of electrons in the plasma membrane, reversibly inhibiting NADH-cytochrome b reductase, the putative key enzyme in the pathway of ferricyanide reduction, and stimulating (or at least not inhibiting) the pathway of Fe(III)-EDTA reduction.

  3. Efficient removal of microcystin-LR by UV-C/H₂O₂ in synthetic and natural water samples.

    PubMed

    He, Xuexiang; Pelaez, Miguel; Westrick, Judy A; O'Shea, Kevin E; Hiskia, Anastasia; Triantis, Theodoros; Kaloudis, Triantafyllos; Stefan, Mihaela I; de la Cruz, Armah A; Dionysiou, Dionysios D

    2012-04-01

    The destruction of the commonly found cyanobacterial toxin, microcystin-LR (MC-LR), in surface waters by UV-C/H(2)O(2) advanced oxidation process (AOP) was studied. Experiments were carried out in a bench scale photochemical apparatus with low pressure mercury vapor germicidal lamps emitting at 253.7 nm. The degradation of MC-LR was a function of UV fluence. A 93.9% removal with an initial MC-LR concentration of 1 μM was achieved with a UV fluence of 80 mJ/cm(2) and an initial H(2)O(2) concentration of 882 μM. When increasing the concentration of MC-LR only, the UV fluence-based pseudo-first order reaction rate constant generally decreased, which was probably due to the competition between by-products and MC-LR for hydroxyl radicals. An increase in H(2)O(2) concentration led to higher removal efficiency; however, the effect of HO scavenging by H(2)O(2) became significant for high H(2)O(2) concentrations. The impact of water quality parameters, such as pH, alkalinity and the presence of natural organic matter (NOM), was also studied. Field water samples from Lake Erie, Michigan and St. Johns River, Florida were employed to evaluate the potential application of this process for the degradation of MC-LR. Results showed that the presence of both alkalinity (as 89.6-117.8 mg CaCO(3)/L) and NOM (as ∼2 to ∼9.5 mg/L TOC) contributed to a significant decrease in the destruction rate of MC-LR. However, a final concentration of MC-LR bellow the guideline value of 1 μg/L was still achievable under current experimental conditions when an initial MC-LR concentration of 2.5 μg/L was spiked into those real water samples. PMID:22177771

  4. 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. PMID:16943010

  5. 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 ...

  6. 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. PMID:27163653

  7. 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

  8. 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.

  9. 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

  10. p53 mutant human glioma cells are sensitive to UV-C-induced apoptosis due to impaired cyclobutane pyrimidine dimer removal.

    PubMed

    Batista, Luis F Z; Roos, Wynand P; Kaina, Bernd; Menck, Carlos F M

    2009-02-01

    The p53 protein is a key regulator of cell responses to DNA damage, and it has been shown that it sensitizes glioma cells to the alkylating agent temozolomide by up-regulating the extrinsic apoptotic pathway, whereas it increases the resistance to chloroethylating agents, such as ACNU and BCNU, probably by enhancing the efficiency of DNA repair. However, because these agents induce a wide variety of distinct DNA lesions, the direct importance of DNA repair is hard to access. Here, it is shown that the induction of photoproducts by UV light (UV-C) significantly induces apoptosis in a p53-mutated glioma background. This is caused by a reduced level of photoproduct repair, resulting in the persistence of DNA lesions in p53-mutated glioma cells. UV-C-induced apoptosis in p53 mutant glioma cells is preceded by strong transcription and replication inhibition due to blockage by unrepaired photolesions. Moreover, the results indicate that UV-C-induced apoptosis of p53 mutant glioma cells is executed through the intrinsic apoptotic pathway, with Bcl-2 degradation and sustained Bax and Bak up-regulation. Collectively, the data indicate that unrepaired DNA lesions induce apoptosis in p53 mutant gliomas despite the resistance of these gliomas to temozolomide, suggesting that efficiency of treatment of p53 mutant gliomas might be higher with agents that induce the formation of DNA lesions whose global genomic repair is dependent on p53.

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

    PubMed

    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

  12. 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.

  13. 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.

  14. 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

  15. H2O2/UV-C treatment of textile preparation wastewater: kinetic investigation on alternative combinations of commercial textile preparation auxiliaries.

    PubMed

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

    2012-01-01

    Four different textile preparation effluents were simulated to examine the applicability of the hydrogen peroxide/ultraviolet-C (H2O2/UV-C) advanced oxidation process for the treatment of real textile preparation (desizing, scouring and bleaching) wastewater bearing the non-ionic surfactant nonyl phenol decaethoxylate (NP-10). In the absence of any textile preparation chemical, NP-10 degradation was complete in 15 min (rate coefficient: 0.22 min(-1)) accompanied by 78% chemical oxygen demand (COD) (rate coefficient: 0.026 min(-1)) and 57% total organic carbon (TOC) (rate coefficient: 0.014 min(-1)) removals achieved after 60 min photochemical treatment. H2O2 consumption rates were not significantly affected by the introduction of carbonate and chloride ions (average rate coefficient: 0.032 min(-1)) at pH values <11.5, above which H2O2 dissociation to its conjugate base HO2(-) became pronounced. The organic, phosphonate-based sequestering agents competed with NP-10 for UV-C light absorption and HO* radicals. H2O2/UV-C oxidation of the simulated textile preparation effluent containing 3.0 g L(-1) Cl(-), 1.5 g L(-1) NaOH and 1.0 g L(-1) diethylenetriamine pentamethylene phosphonic acid (DTPMP) resulted in the worst treatment performance due to its high pH and organic carbon content. For this textile preparation effluent, NP-10 abatement was complete in 100min (rate coefficient: 0.018 min(-1)), while COD and TOC removals dropped down to only 16% and 8%, respectively, achieved after 60 min treatment. The highest H2O2/UV-C oxidation efficiency resulting in 34% COD and 28% TOC removals was obtained for the simulated textile preparation effluent comprising of 3.0 g L(-1) Cl(-), 1.5 g L(-1) NaOH and 1.0 g L(-1) 1-hydroxy ethylidene-1,1-diphosphonic acid (HEDP). For this textile preparation effluent, NP-10 degradation was complete after 50 min (rate coefficient: 0.061 min(-1)) exposure to H2O2/UV-C treatment. PMID:22988612

  16. 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.

  17. 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. PMID:27570269

  18. 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. PMID:26360228

  19. 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

    2016-07-01

    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. PMID:27050143

  20. Using survival analysis to investigate the effect of UV-C and heat treatment on storage rot of strawberry and sweet cherry.

    PubMed

    Marquenie, D; Michiels, C W; Geeraerd, A H; Schenk, A; Soontjen, C; Van Impe, J F; Nicolaï, B M

    2002-03-01

    Ultraviolet light and heat treatment are proposed as alternative techniques for the use of chemicals to reduce the development of the spoilage fungi Botrytis cinerea and Monilinia fructigena on strawberry and sweet cherry, respectively, during storage. In order to investigate the effect of both physical techniques on microbial inactivation and on fruit quality, inoculated berries were subjected to different temperatures (40-48 degrees C) and UV-C doses (0.05-1.50 J/cm2). For each condition, 20 berries were used. After the treatment, fungal growth, visual damage (holes, stains) and fruit firmness were evaluated during a period of 10 days. The experimental data were analysed statistically using survival analysis techniques. Fungal growth on strawberries was significantly retarded using UV-C doses of 0.05 J/cm2 and higher. The same treatment had no significant effect when applied to cherries. The highest doses (1.00 and 1.50 J/cm2) had a negative effect on the calyx of the strawberry, causing browning and drying of the leaves. No beneficial effect of a low temperature treatment (40-48 degrees C) on the shelf life of strawberries was observed, but fungal development on cherries was retarded at temperatures of 45 and 48 degrees C. These temperatures caused severe damage on strawberries (soft stains, holes, decreased firmness), but had no influence on the quality of sweet cherries.

  1. 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.

  2. 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.

  3. Comparison of ozone and UV-C treatments on the postharvest stilbenoid monomer, dimer, and trimer induction in var. 'Superior' white table grapes.

    PubMed

    González-Barrio, Rocío; Beltrán, David; Cantos, Emma; Gil, María I; Espín, Juan Carlos; Tomás-Barberán, Francisco A

    2006-06-14

    Postharvest treatment of seedless white table grapes (var. 'Superior') with different gas ozone concentrations (3.88 and 1.67 g/h) for 1, 3, and 5 h induced an increase in stilbenoid biosynthesis [trans-resveratrol, piceatannol, and viniferinas (resveratrol dehydrodimers and dehydrotrimers)] during storage at 22 degrees C and 95% relative humidity. The maximal resveratrol concentration was reached after 2 days of storage, and this amount was similar to that induced by optimized UV-C treatments (1 min, 510 W, 40 cm). Although similar resveratrol concentrations accumulated in grapes after both UV-C and O3 treatments (maximum ozone production and time), the ozone treatment was more efficient in inducing viniferins accumulation in grape berries. A sequence in the biosynthesis of stilbenoids was observed, starting with the resveratrol monomer, continuing with the resveratrol dehydrodimers epsilon-viniferin and delta-viniferin, and ending with four different resveratrol dehydrotrimers. These trimers were different from alpha-viniferin, a trimer previously reported to be induced in grapes after biotic and abiotic stresses. Two alpha-viniferin isomers were also detected in the ozone-treated grapes, although at very low concentrations that prevented their quantification. PMID:16756350

  4. 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.

  5. 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. PMID:27052716

  6. 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

    2016-07-01

    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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. UV-C-Induced alleviation of transcriptional gene silencing through plant-plant communication: Key roles of jasmonic acid and salicylic acid pathways.

    PubMed

    Xu, Wei; Wang, Ting; Xu, Shaoxin; Li, Fanghua; Deng, Chenguang; Wu, Lijun; Wu, Yuejin; Bian, Po

    2016-08-01

    Plant stress responses at the epigenetic level are expected to allow more permanent changes of gene expression and potentially long-term adaptation. While it has been reported that plants subjected to adverse environments initiate various stress responses in their neighboring plants, little is known regarding epigenetic responses to external stresses mediated by plant-plant communication. In this study, we show that DNA repetitive elements of Arabidopsis thaliana, whose expression is inhibited epigenetically by transcriptional gene silencing (TGS) mechanism, are activated by UV-C irradiation through airborne plant-plant and plant-plant-plant communications, accompanied by DNA demethylation at CHH sites. Moreover, the TGS is alleviated by direct treatments with exogenous methyl jasmonate (MeJA) and methyl salicylate (MeSA). Further, the plant-plant and plant-plant-plant communications are blocked by mutations in the biosynthesis or signaling of jasmonic acid (JA) or salicylic acid (SA), indicating that JA and SA pathways are involved in the interplant communication for epigenetic responses. For the plant-plant-plant communication, stress cues are relayed to the last set of receiver plants by promoting the production of JA and SA signals in relaying plants, which exhibit upregulated expression of genes for JA and SA biosynthesis and enhanced emanation of MeJA and MeSA. PMID:27131397

  12. A structural study of the retinal photoreceptor, plexiform and ganglion cell layers following exposure to UV-B and UV-C radiation in the albino rat.

    PubMed

    de Oliveira Miguel, Nadia Campos; Meyer-Rochow, Victor Benno; Allodi, Silvana

    2003-01-01

    Over the last two decades, ultraviolet radiation levels (UV), reaching the Earth's surface, have been increasing at a rate of 1.5% per each 1% loss of the ozone layer. Moreover, artificial UV-sources have also proliferated and contributed to the rising UV-stress that many organisms have to face. To assess how the vertebrate retina responds to an exposure of short wavelength UV, we focused our attention on the rat retina, observing photoreceptor (containing outer and inner segments of rods and cones), inner plexiform, and ganglion cell layers by light and transmission electron microscopy using conventional and cytochemical techniques. We analyzed how cells of the layers in question responded to a 30 min exposure to UV-C and UV-B radiation with doses of 7200 and 590 J/cm(2), respectively. The results show that there are significant changes in the nuclei and cytoplasmic organelles of the exposed retinae when compared with those of the unexposed controls. The changes include an increase in heterochromatin, distension of rough endoplasmic reticulum, mitochondrial disruptions, and increases in the number of myelin bodies. The recorded morphological changes, especially those of the ganglion cells, are suggestive of apoptotic processes and show that the exposure of vertebrate retina to wavelengths ranging from 254 to 312 nm can produce alterations that are likely to impact negatively on the retina's proper functioning.

  13. UV-C-Induced alleviation of transcriptional gene silencing through plant-plant communication: Key roles of jasmonic acid and salicylic acid pathways.

    PubMed

    Xu, Wei; Wang, Ting; Xu, Shaoxin; Li, Fanghua; Deng, Chenguang; Wu, Lijun; Wu, Yuejin; Bian, Po

    2016-08-01

    Plant stress responses at the epigenetic level are expected to allow more permanent changes of gene expression and potentially long-term adaptation. While it has been reported that plants subjected to adverse environments initiate various stress responses in their neighboring plants, little is known regarding epigenetic responses to external stresses mediated by plant-plant communication. In this study, we show that DNA repetitive elements of Arabidopsis thaliana, whose expression is inhibited epigenetically by transcriptional gene silencing (TGS) mechanism, are activated by UV-C irradiation through airborne plant-plant and plant-plant-plant communications, accompanied by DNA demethylation at CHH sites. Moreover, the TGS is alleviated by direct treatments with exogenous methyl jasmonate (MeJA) and methyl salicylate (MeSA). Further, the plant-plant and plant-plant-plant communications are blocked by mutations in the biosynthesis or signaling of jasmonic acid (JA) or salicylic acid (SA), indicating that JA and SA pathways are involved in the interplant communication for epigenetic responses. For the plant-plant-plant communication, stress cues are relayed to the last set of receiver plants by promoting the production of JA and SA signals in relaying plants, which exhibit upregulated expression of genes for JA and SA biosynthesis and enhanced emanation of MeJA and MeSA.

  14. 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...

  15. 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,

  16. Photodegradation of 4-tert-butylphenol in aqueous solution by UV-C, UV/H2O2 and UV/S2O8(2-) system.

    PubMed

    Wu, Yanlin; Zhu, Xiufen; Chen, Hongche; Dong, Wenbo; Zhao, Jianfu

    2016-01-01

    The photolytic degradation of 4-tert-butylphenol (4-t-BP) in aqueous solution was investigated using three kinds of systems: UV-C directly photodegradation system, UV/H2O2 and UV/S2O8(2-) system. Under experimental conditions, the degradation rate of 4-t-BP was in the order: UV/S2O8(2-) > UV/H2O2 > UV-C. The reaction kinetics of UV/S2O8(2-) system were thoroughly investigated. The increase of S2O8(2-) concentration enhanced the 4-t-BP degradation rate, which was inhibited when the concentration of S2O8(2-) exceeded 4.0 mM. The highest efficacy in 4-t-BP degradation was obtained at pH 6.5. The oxidation rate of 4-t-BP could be accelerated by increasing the reaction temperature and irradiation intensity. The highest rate constant (kobs = 8.4 × 10(-2) min(-1)) was acquired when the reaction temperature was 45 °C. The irradiation intensity was measured by irradiation distance, and the optimum irradiation distance was 10 cm. Moreover, the preliminary mechanism of 4-t-BP degradation was studied. The bond scission of the 4-t-BP molecule occurred by the oxidation of SO4(•-), which dimerized and formed two main primary products. Under the conditions of room temperature (25 °C ± 1 °C) and low concentration of K2S2O8 (0.5 mM), 35.4% of total organic carbon (TOC) was removed after 8.5-h irradiation. The results showed that UV/S2O8(2-) system was effective for the degradation of 4-t-BP.

  17. 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.

  18. Materials Data on LuB2Os3 (SG:191) by Materials Project

    DOE Data Explorer

    Kristin Persson

    2016-02-11

    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

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

    DOE Data Explorer

    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

  20. Materials Data on LuB2C (SG:135) by Materials Project

    SciTech Connect

    Kristin Persson

    2015-03-19

    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

  1. Materials Data on LuB2 (SG:191) by Materials Project

    SciTech Connect

    Kristin Persson

    2014-11-02

    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

  2. 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...

  3. 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. PMID:25626463

  4. 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

  5. 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...

  6. Effectiveness of UV-C equipped vacuum at reducing culturable surface-bound microorganisms on carpets.

    PubMed

    Lutz, Eric A; Sharma, Smita; Casto, Bruce; Needham, Glen; Buckley, Timothy J

    2010-12-15

    Carpets are both sinks and sources for exposure to chemicals, allergens, and microbes and consequently influence health, including asthma, allergies, and infectious diseases. Asthmatics, children, and the immune-compromised are particularly vulnerable to health risks resulting from exposure to carpet contaminants. To address this risk, a commercial upright vacuum cleaner with an ultraviolet germicidal lamp (λ=253.7 nm, UVC) has been developed for residential and commercial uses. However, its effectiveness in reducing microbial load on real-world carpets has not been previously demonstrated. Accordingly, the purpose of the current study was to evaluate the effectiveness of a UVC-equipped vacuum in reducing the carpet surface-bound microbial load. This was accomplished by comparing the carpet microbial surface load from pre- to post-treatment of 9 ft(2) in-use carpet sections under three treatment scenarios: 1) UVC alone (UV), 2) the beater-bar plus vacuum (BB+Vac), or 3) a combination of all three (COMB). Each treatment was two minutes in duration. Microbial surface loads were measured by pressing contact plates containing Sabourauds Dextrose agar onto the carpet surface. In-use carpets from three locations were tested in place. The treatment effect was evaluated at two levels. First, we considered the mean reduction in CFU from pre- to post-treatment for each 9 ft(2) carpet grid (n = 4 for each treatment). The second level considered each 1 ft(2) section using a paired analysis (n = 40 to 49 for each treatment). A total of 125 pre/post-sample pairs were collected across the three treatments. Results showed that all three treatments were associated with a reduction in carpet microbial load (p < 0.0001). The COMB yielded the largest reduction of 13 CFU/plate (87% reduction) and was approximately the sum of the individual effects of either UVC (6.6 CFU/plate, 60% reduction, p = 0.009) or BB+Vac (7.3 CFU/plate, 78% reduction, p < 0.0001). We therefore conclude that a UVC-equipped vacuum approximately doubles the unit's effectiveness in reducing surface-bound microbial load, thereby holding promise as a means for decreasing indoor infectious disease risk.

  7. Inactivation of Salmonella enterica by UV-C Light Alone and in Combination with Mild Temperatures

    PubMed Central

    Gayán, E.; Serrano, M. J.; Raso, J.; Álvarez, I.

    2012-01-01

    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. PMID:23001665

  8. 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.

  9. 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...

  10. 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.

  11. 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...

  12. Effect of deoxyribonucleosides on the hypersensitivity of human peripheral blood lymphocytes to UV-B and UV-C irradiation.

    PubMed

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

    1994-07-01

    We have previously shown that non-cycling (unstimulated) human lymphocytes from normal donors show extreme hypersensitivity to UV-B irradiation, and are killed by an excisable lesion which is not a pyrimidine dimer or 6-4 photoproduct. In this paper we show that addition of the 4 deoxyribonucleosides to the medium, each at 10(-5) M, substantially increased the survival of non-cycling normal human T-lymphocytes following UV-B irradiation and substantially reduced the frequency of excision-related strand breaks in human mononuclear cells. Addition of ribonucleosides to the medium did not enhance excision-break rejoining. The survival of fibroblasts, of cycling T-lymphocytes and of unstimulated xeroderma pigmentosum T-lymphocytes was not enhanced by deoxyribonucleosides. This suggests that the hypersensitivity is due to reduced rejoining of excision breaks as a consequence of low intracellular deoxyribonucleotide pools and that it can be redressed by supplementation of the medium with deoxyribonucleosides or upregulation of ribonucleotide reductase following mitogen stimulation. We suggest that UV-B forms an additional DNA lesion which is not a pyrimidine dimer or 6-4 photoproduct, which is relatively common, and at which incision is particularly efficient. In fibroblasts, repair of this lesion is completed with high efficiency, whereas in normal unstimulated T-lymphocytes, rapid incision exacerbates the effects of the reduced rate of strand rejoining and leads to cell death. PMID:7517007

  13. 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.

  14. The combined effects of UV-C radiation and H2O2 on Microcystis aeruginosa, a bloom-forming cyanobacterium.

    PubMed

    Wang, Binliang; Wang, Xi; Hu, Yiwei; Chang, Mingxian; Bi, Yonghong; Hu, Zhengyu

    2015-12-01

    In order to get insight into the impacts of UVC/H2O2 on Microcystis aeruginosa, physiological and morphological changes as well as toxicity were detected under different UVC/H2O2 treatments. In the presence of sole UVC or H2O2, the net oxygen evolution rate decreased significantly (p<0.05) since activity of photosystem II (PSII) was inhibited. Meanwhile, increase of intracellular reactive oxygen species (ROS), degradation of microcystin (MC) and ultrastructure destructions were observed. Under sole UVC treatment, no changes happened in the activity of photosystem I (PSI), but the degradation of D1 protein was observed. Under sole H2O2 treatment, an increase of malondialdehyde, aggregation of D1 protein and deformation of the thylakoid membrane were observed. ROS content under H2O2 treatment was about 5 times than that under UVC treatment. Combined use of UVC and H2O2, as well as 20mJcm(-2) UVC and 60μM H2O2, showed high synergetic effects. Obvious damage to membrane systems, the marked degradation of MC and inhibition of the photosystems were observed. It could be deduced that UVC worked on intracellular membrane components directly and the damaged oxygen-evolving complex, which was followed by the D1 protein degradation. H2O2 oxidised the membrane lipids via an ROS-mediated process, with thylakoid injury and the aggregation of D1 protein being the lethal mechanisms, and both PSII and PSI being the attacking targets. With regard towards the effective inactivation of M. aeruginosa and high removal of MC, UVC/H2O2 proposed a novel practical method in controlling cyanobacterial blooms. PMID:26092198

  15. The combined effects of UV-C radiation and H2O2 on Microcystis aeruginosa, a bloom-forming cyanobacterium.

    PubMed

    Wang, Binliang; Wang, Xi; Hu, Yiwei; Chang, Mingxian; Bi, Yonghong; Hu, Zhengyu

    2015-12-01

    In order to get insight into the impacts of UVC/H2O2 on Microcystis aeruginosa, physiological and morphological changes as well as toxicity were detected under different UVC/H2O2 treatments. In the presence of sole UVC or H2O2, the net oxygen evolution rate decreased significantly (p<0.05) since activity of photosystem II (PSII) was inhibited. Meanwhile, increase of intracellular reactive oxygen species (ROS), degradation of microcystin (MC) and ultrastructure destructions were observed. Under sole UVC treatment, no changes happened in the activity of photosystem I (PSI), but the degradation of D1 protein was observed. Under sole H2O2 treatment, an increase of malondialdehyde, aggregation of D1 protein and deformation of the thylakoid membrane were observed. ROS content under H2O2 treatment was about 5 times than that under UVC treatment. Combined use of UVC and H2O2, as well as 20mJcm(-2) UVC and 60μM H2O2, showed high synergetic effects. Obvious damage to membrane systems, the marked degradation of MC and inhibition of the photosystems were observed. It could be deduced that UVC worked on intracellular membrane components directly and the damaged oxygen-evolving complex, which was followed by the D1 protein degradation. H2O2 oxidised the membrane lipids via an ROS-mediated process, with thylakoid injury and the aggregation of D1 protein being the lethal mechanisms, and both PSII and PSI being the attacking targets. With regard towards the effective inactivation of M. aeruginosa and high removal of MC, UVC/H2O2 proposed a novel practical method in controlling cyanobacterial blooms.

  16. Degradation rates of benzotriazoles and benzothiazoles under UV-C irradiation and the advanced oxidation process UV/H2O2.

    PubMed

    Bahnmüller, Sabrina; Loi, Clara H; Linge, Kathryn L; Gunten, Urs von; Canonica, Silvio

    2015-05-01

    Benzotriazoles (BTs) and benzothiazoles (BTHs) are extensively used chemicals found in a wide range of household and industrial products. They are chemically stable and are therefore ubiquitous in the aquatic environment. The present study focuses on the potential of ultraviolet (UV) irradiation, alone or in combination with hydrogen peroxide (H2O2), to remove BTs and BTHs from contaminated waters. Six compounds, three out of each chemical class, were investigated using a low-pressure mercury lamp (main emission at 254 nm) as the radiation source. Initially, the direct phototransformation kinetics and quantum yield in dilute aqueous solution was studied over the pH range of 4-12. All BTs and BTHs, except for benzothiazole, exhibited pH-dependent direct phototransformation rate constants and quantum yields in accordance to their acid-base speciation (7.1 < pKa < 8.9). The direct phototransformation quantum yields (9.0 × 10(-4)-3.0 × 10(-2) mol einstein(-1)), as well as the photon fluence-based rate constants (1.2-48 m(2) einstein(-1)) were quite low. This suggests that UV irradiation alone is not an efficient method to remove BTs and BTHs from impacted waters. The second-order rate constants for the reaction of selected BTs and BTHs with the hydroxyl radical were also determined, and found to fall in the range of 5.1-10.8 × 10(9) M(-1) s(-1), which is typical for aromatic contaminants. Finally, the removal of BTs and BTHs was measured in wastewater and river water during application of UV irradiation or the advanced oxidation process UV/H2O2. The latter process provided an efficient removal, mostly due to the effect of the hydroxyl radical, that was comparable to other aromatic aquatic contaminants, in terms of energy requirement or treatment costs.

  17. Degradation rates of benzotriazoles and benzothiazoles under UV-C irradiation and the advanced oxidation process UV/H2O2.

    PubMed

    Bahnmüller, Sabrina; Loi, Clara H; Linge, Kathryn L; Gunten, Urs von; Canonica, Silvio

    2015-05-01

    Benzotriazoles (BTs) and benzothiazoles (BTHs) are extensively used chemicals found in a wide range of household and industrial products. They are chemically stable and are therefore ubiquitous in the aquatic environment. The present study focuses on the potential of ultraviolet (UV) irradiation, alone or in combination with hydrogen peroxide (H2O2), to remove BTs and BTHs from contaminated waters. Six compounds, three out of each chemical class, were investigated using a low-pressure mercury lamp (main emission at 254 nm) as the radiation source. Initially, the direct phototransformation kinetics and quantum yield in dilute aqueous solution was studied over the pH range of 4-12. All BTs and BTHs, except for benzothiazole, exhibited pH-dependent direct phototransformation rate constants and quantum yields in accordance to their acid-base speciation (7.1 < pKa < 8.9). The direct phototransformation quantum yields (9.0 × 10(-4)-3.0 × 10(-2) mol einstein(-1)), as well as the photon fluence-based rate constants (1.2-48 m(2) einstein(-1)) were quite low. This suggests that UV irradiation alone is not an efficient method to remove BTs and BTHs from impacted waters. The second-order rate constants for the reaction of selected BTs and BTHs with the hydroxyl radical were also determined, and found to fall in the range of 5.1-10.8 × 10(9) M(-1) s(-1), which is typical for aromatic contaminants. Finally, the removal of BTs and BTHs was measured in wastewater and river water during application of UV irradiation or the advanced oxidation process UV/H2O2. The latter process provided an efficient removal, mostly due to the effect of the hydroxyl radical, that was comparable to other aromatic aquatic contaminants, in terms of energy requirement or treatment costs. PMID:25725202

  18. 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. PMID:25107964

  19. 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 Central

    Ha, Jae-Won

    2014-01-01

    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. PMID:25107964

  20. 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.

  1. Disposition of human recombinant lubricin in naive rats and in a rat model of post-traumatic arthritis after intra-articular or intravenous administration.

    PubMed

    Vugmeyster, Yulia; Wang, Qin; Xu, Xin; Harrold, John; Daugusta, Daren; Li, Jian; Zollner, Richard; Flannery, Carl R; Rivera-Bermúdez, Moisés A

    2012-03-01

    We have recently demonstrated that intra-articular (IA) administration of human recombinant lubricin, LUB:1, significantly inhibited cartilage degeneration and pain in the rat meniscal tear model of post-traumatic arthritis. In this report, we show that after a single IA injection to naïve rats and rats that underwent unilateral meniscal tear, [(125)I]LUB:1 had a tri-phasic disposition profile, with the alpha, beta, and gamma half-life estimates of 4.5 h, 1.5 days, and 2.1 weeks, respectively. We hypothesize that the terminal phase kinetics was related to [(125)I]LUB:1 binding to its ligands. [(125)I]LUB:1 was detected on articular cartilage surfaces as long as 28 days after single IA injection. Micro-autoradiography analysis suggested that [(125)I]LUB:1 tended to localize to damaged joint surfaces in rats with meniscal tear. After a single intravenous (IV) dose to rats, [(125)I]LUB:1 was eliminated rapidly from the systemic circulation, with a mean total body clearance of 154 mL/h/kg and a mean elimination half-life (t (1/2)) of 6.7 h. Overall, LUB:1 has met a desired disposition profile of a potential therapeutic intended for an IA administration: target tissue (knee) retention and fast elimination from the systemic circulation after a single IA or IV dose.

  2. Lubricin: a novel means to decrease bacterial adhesion and proliferation.

    PubMed

    Aninwene, George E; Abadian, Pegah N; Ravi, Vishnu; Taylor, Erik N; Hall, Douglas M; Mei, Amy; Jay, Gregory D; Goluch, Edgar D; Webster, Thomas J

    2015-02-01

    This study investigated the ability of lubricin (LUB) to prevent bacterial attachment and proliferation on model tissue culture polystyrene surfaces. The findings from this study indicated that LUB was able to reduce the attachment and growth of Staphylococcus aureus on tissue culture polystyrene over the course of 24 h by approximately 13.9% compared to a phosphate buffered saline (PBS)-soaked control. LUB also increased S. aureus lag time (the period of time between the introduction of bacteria to a new environment and their exponential growth) by approximately 27% compared to a PBS-soaked control. This study also indicated that vitronectin (VTN), a protein homologous to LUB, reduced bacterial S. aureus adhesion and growth on tissue culture polystyrene by approximately 11% compared to a PBS-soaked control. VTN also increased the lag time of S. aureus by approximately 43%, compared to a PBS-soaked control. Bovine submaxillary mucin was studied because there are similarities between it and the center mucin-like domain of LUB. Results showed that the reduction of S. aureus and Staphylococcus epidermidis proliferation on mucin coated surfaces was not as substantial as that seen with LUB. In summary, this study provided the first evidence that LUB reduced the initial adhesion and growth of both S. aureus and S. epidermidis on a model surface to suppress biofilm formation. These reductions in initial bacteria adhesion and proliferation can be beneficial for medical implants and, although requiring more study, can lead to drastically improved patient outcomes.

  3. Lubricin: A novel means to decrease bacterial adhesion and proliferation

    PubMed Central

    Aninwene, George E.; Abadian, Pegah N.; Ravi, Vishnu; Taylor, Erik N.; Hall, Douglas M.; Mei, Amy; Jay, Gregory D.; Goluch, Edgar D.; Webster, Thomas J.

    2015-01-01

    This study investigated the ability of lubricin (LUB) to prevent bacterial attachment and proliferation on model tissue culture polystyrene surfaces. The findings from this study indicated that LUB was able to reduce the attachment and growth of Staphylococcus aureus on tissue culture polystyrene over the course of 24 h by approximately 13.9% compared to a phosphate buffered saline (PBS)-soaked control. LUB also increased S. aureus lag time (the period of time between the introduction of bacteria to a new environment and their exponential growth) by approximately 27% compared to a PBS-soaked control. This study also indicated that vitronectin (VTN), a protein homologous to LUB, reduced bacterial S. aureus adhesion and growth on tissue culture polystyrene by approximately 11% compared to a PBS-soaked control. VTN also increased the lag time of S. aureus by approximately 43%, compared to a PBS-soaked control. Bovine submaxillary mucin was studied because there are similarities between it and the center mucin-like domain of LUB. Results showed that the reduction of S. aureus and Staphylococcus epidermidis proliferation on mucin coated surfaces was not as substantial as that seen with LUB. In summary, this study provided the first evidence that LUB reduced the initial adhesion and growth of both S. aureus and S. epidermidis on a model surface to suppress biofilm formation. These reductions in initial bacteria adhesion and proliferation can be beneficial for medical implants and, although requiring more study, can lead to drastically improved patient outcomes. PMID:24737699

  4. Health Information in Hmong (Hmoob): MedlinePlus

    MedlinePlus

    ... Dentistry Cosmetic Dentistry - English Kev Kho Kom Hniav Zoo Nkauj - Hmoob (Hmong) California Dental Association Dental Implants - ... Diabetes - English Saib Xyuas Koj Lub Plawv Kom Zoo Soj Ntsuam Koj Tus Kabmob Muaj Ntshav Qab ...

  5. Androgen insensitivity syndrome

    MedlinePlus

    ... at the tip Reifenstein syndrome (also known as Gilbert-Dreyfus syndrome or Lubs syndrome) Infertile male syndrome ... F, Leveno KJ, Bloom SL, et al., eds. Williams Obstetrics . 23rd ed. New York, NY: McGraw-Hill, ...

  6. The Effects of Supplemental Intra-Articular Lubricin and Hyaluronic Acid on the Progression of Post-Traumatic Arthritis in the Anterior Cruciate Ligament Deficient Rat Knee

    PubMed Central

    Teeple, Erin; Elsaid, Khaled A.; Jay, Gregory D.; Zhang, Ling; Badger, Gary J.; Akelman, Matthew; Bliss, Thomas F.; Fleming, Braden C.

    2010-01-01

    Background Lubricin and hyaluronic acid lubricate articular cartilage and prevent wear. Because lubricin loss occurs following ACL injury, intra-articular lubricin injections may reduce cartilage damage in the ACL deficient knee. Purpose To determine if lubricin and/or hyaluronic acid supplementation will reduce cartilage damage in the ACL deficient knee. Study Design Controlled laboratory study Methods 36 male rats, 3 months old, underwent unilateral ACL transection. They were randomized to four treatments: 1) saline (PBS), 2) hyaluronic acid (HA), 3) purified human lubricin (LUB), and 4) LUB and HA (LUB+HA). Intra-articular injections were given twice weekly for four weeks starting one week after surgery. Knees were harvested one week following final injection. Radiographs of each limb and synovial fluid lavages were obtained at harvest. Histology was performed to assess cartilage damage using Safranin O/Fast green staining. Radiographs were scored for the severity of joint degeneration using the modified Kellgren-Lawrence scale. Synovial fluid levels of sulfated glycosaminoglycan, collagen II breakdown, IL-1β, TNF-α and lubricin were measured using ELISA. Results Treatment with LUB or LUB+HA significantly decreased radiographic and histologic scores of cartilage damage (p=0.039, p=0.015, respectively) when compared to the PBS and HA conditions. There was no evidence of an effect of HA nor was the LUB effect HA dependent suggesting that the addition of HA did not further reduce damage. The synovial fluid of knees treated with LUB had significantly more lubricin in the synovial fluid at euthanasia, though there were no differences in the other cartilage metabolism biomarkers. Conclusions Supplemental intra-articular LUB reduced cartilage damage in the ACL transected rat knee 6 weeks after injury, while treatment with HA did not. Clinical Relevance Although longer-term studies are needed, intra-articular supplementation (tribosupplementation) with lubricin

  7. Synergistic interactions between grafted hyaluronic acid and lubricin provide enhanced wear protection and lubrication.

    PubMed

    Das, Saurabh; Banquy, Xavier; Zappone, Bruno; Greene, George W; Jay, Gregory D; Israelachvili, Jacob N

    2013-05-13

    Normal (e.g., adhesion) and lateral (friction) forces were measured between physisorbed and chemically grafted layers of hyaluronic acid (HA), an anionic polyelectrolyte in the presence of lubricin (Lub), a mucinous glycoprotein, on mica surfaces using a surface forces apparatus (SFA). This work demonstrates that high friction coefficients between the surfaces do not necessarily correlate with surface damage and that chemically grafted HA acts synergistically with Lub to provide friction reduction and enhanced wear protection to the surfaces. Surface immobilization of HA by grafting is necessary for such wear protection. Increasing the concentration of Lub enhances the threshold load that a chemically grafted HA surface can be subjected to before the onset of wear. Addition of Lub does not have any beneficial effect if HA is physisorbed to the mica surfaces. Damage occurs at loads less than 1 mN regardless of the amount of Lub, indicating that the molecules in the bulk play little or no role in protecting the surfaces from damage. Lub penetrates into the chemically bound HA to form a visco-elastic gel that reduces the coefficient of friction as well as boosts the strength of the surface against abrasive wear (damage).

  8. Fibronectin mediates enhanced wear protection of lubricin during shear.

    PubMed

    Andresen Eguiluz, Roberto C; Cook, Sierra G; Brown, Cory N; Wu, Fei; Pacifici, Noah J; Bonassar, Lawrence J; Gourdon, Delphine

    2015-09-14

    Fibronectin (FN) is a glycoprotein found in the superficial zone of cartilage; however, its role in the lubrication and the wear protection of articular joints is unknown. In this work, we have investigated the molecular interactions between FN and various components of the synovial fluid such as lubricin (LUB), hyaluronan (HA), and serum albumin (SA), which are all believed to contribute to joint lubrication. Using a Surface Forces Apparatus, we have measured the normal (adhesion/repulsion) and lateral (friction) forces across layers of individual synovial fluid components physisorbed onto FN-coated mica substrates. Our chief findings are (i) FN strongly tethers LUB and HA to mica, as indicated by high and reversible long-range repulsive normal interactions between surfaces, and (ii) FN and LUB synergistically enhance wear protection of surfaces during shear, as suggested by the structural robustness of FN+LUB layers under pressures up to about 4 MPa. These findings provide new insights into the role of FN in the lubricating properties of synovial fluid components sheared between ideal substrates and represent a significant step forward in our understanding of cartilage damage involved in diseases such as osteoarthritis.

  9. 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

  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

    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.

  11. 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.

  12. 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.

  13. 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.

  14. Effect of UV treatment on antioxidant capacity, antioxidant enzyme activity and decay in strawberry fruit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The changes in antioxidant capacity, enzyme activity and decay inhibition in strawberry fruit (Fragaria x ananassa) illuminated with different UV-C dosages were investigated. Three UV-C illumination durations and dosages, 1 min, 5 min and 10 min, (0.43, 2.15 and 4.30 kJ m-2) tested promoted the anti...

  15. 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. PMID:27451228

  16. 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

  17. Physico-chemical changes in tomato with modified atmosphere storage and UV treatment.

    PubMed

    Vunnam, R; Hussain, A; Nair, G; Bandla, R; Gariepy, Y; Donnelly, D J; Kubow, S; Raghavan, G S V

    2014-09-01

    Physico-chemical changes in ripe tomato (Lycopersicon esculentum Mill.) were analyzed on day 0 and 2 weeks after ultraviolet-C (UV-C) light treatment or modified atmosphere (MA) storage and combined UV-C + MA storage at 10 °C. Modified atmosphere packaging (MAP) film was used to create MA conditions. The tomatoes were evaluated for surface colour, mass loss, firmness, respiration rate, total soluble solids and antioxidant capacity. The tomatoes treated with UV-C and MA storage underwent least changes in their physico-chemical properties, indicating that combination of UV-C and MA storage was successful in retaining the attributes of the fresh product. The increase in antioxidant capacity of the tomatoes during UV-C treatment suggested that UV treatment during post harvest handling may be successfully combined with MA storage, resulting in a product with better nutritive value. PMID:25190870

  18. 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...

  19. Ultraviolet C irradiation at 0.5 kJ.m(-)(2) reduces decay without causing damage or affecting postharvest quality of star ruby grapefruit (C. paradisi Macf.).

    PubMed

    D'hallewin, G; Schirra, M; Pala, M; Ben-Yehoshua, S

    2000-10-01

    Star Ruby grapefruit [Citrus paradisi (Macf.)] were harvested in November, February, and May, treated with ultraviolet C (UV-C) light at 0.5, 1.5, or 3.0 kJ.m(-)(2), and then stored at 7 degrees C and 90-95% relative humidity (RH) for 4 weeks with 1 additional week at 20 degrees C and approximately 80% RH. Untreated fruits were used as control. UV-C irradiation at 0.5 kJ.m(-)(2) effectively reduced decay development as compared to nontreated fruit without causing damage. Irradiation at dosages >0.5 kJ.m(-)(2) did not further improve decay control and caused rind browning and necrotic peel, the extent of damage depending on treatment dosage and harvest date. The percentage of damaged fruit after irradiation at the higher UV-C dosages was significantly higher in fruit harvested in November; differences between fruits harvested in February and May were negligible. After UV-C irradiation, the phytoalexins scoparone and scopoletin accumulated in flavedo tissue, their amounts depending on harvest date and UV-C dosage. Both phytoalexins showed similar accumulation patterns, although the concentrations of scoparone were much lower than those of scopoletin. Phytoalexin levels increased in most samples as the treatment dosage increased. No detectable levels of scoparone and scopoletin could be found in nonirradiated fruit. The influence of UV-C treatments on soluble solids concentration and titratable acidity of juice was negligible. PMID:11052702

  20. Ultraviolet-C Light Sanitization of English Cucumber (Cucumis sativus) Packaged in Polyethylene Film.

    PubMed

    Tarek, Abdussamad R; Rasco, Barbara A; Sablani, Shyam S

    2016-06-01

    Food safety is becoming an increasing concern in the United States. This study investigated the effects of ultraviolet-C (UV-C) light as a postpackaging bactericidal treatment on the quality of English cucumber packaged in polyethylene (PE) film. Escherichia coli k-12 was used as a surrogate microbe. The microbial growth and physical properties of packaged cucumbers were analyzed during a 28-d storage period at 5 °C. Inoculating packaged cucumbers treated at 23 °C for 6 min with UV-C (560 mJ/cm(2) ) resulted in a 1.60 log CFU/g reduction. However, this treatment had no significant effect (P > 0.05) on the water vapor transmission rate or oxygen transmission rate of the PE film. Results show that UV-C light treatment delayed the loss of firmness and yellowing of English cucumber up to 28 d at 5 °C. In addition, UV-C light treatment extended the shelf life of treated cucumber 1 wk longer compared to untreated cucumbers. Electron microscopy images indicate that UV-C light treatment influences the morphology of the E. coli k-12 cells. Findings demonstrate that treating cucumbers with UV-C light following packaging in PE film can reduce bacterial populations significantly and delay quality loss. This technology may also be effective for other similarly packaged fresh fruits and vegetables.

  1. Ultraviolet C irradiation at 0.5 kJ.m(-)(2) reduces decay without causing damage or affecting postharvest quality of star ruby grapefruit (C. paradisi Macf.).

    PubMed

    D'hallewin, G; Schirra, M; Pala, M; Ben-Yehoshua, S

    2000-10-01

    Star Ruby grapefruit [Citrus paradisi (Macf.)] were harvested in November, February, and May, treated with ultraviolet C (UV-C) light at 0.5, 1.5, or 3.0 kJ.m(-)(2), and then stored at 7 degrees C and 90-95% relative humidity (RH) for 4 weeks with 1 additional week at 20 degrees C and approximately 80% RH. Untreated fruits were used as control. UV-C irradiation at 0.5 kJ.m(-)(2) effectively reduced decay development as compared to nontreated fruit without causing damage. Irradiation at dosages >0.5 kJ.m(-)(2) did not further improve decay control and caused rind browning and necrotic peel, the extent of damage depending on treatment dosage and harvest date. The percentage of damaged fruit after irradiation at the higher UV-C dosages was significantly higher in fruit harvested in November; differences between fruits harvested in February and May were negligible. After UV-C irradiation, the phytoalexins scoparone and scopoletin accumulated in flavedo tissue, their amounts depending on harvest date and UV-C dosage. Both phytoalexins showed similar accumulation patterns, although the concentrations of scoparone were much lower than those of scopoletin. Phytoalexin levels increased in most samples as the treatment dosage increased. No detectable levels of scoparone and scopoletin could be found in nonirradiated fruit. The influence of UV-C treatments on soluble solids concentration and titratable acidity of juice was negligible.

  2. Ultraviolet-C Light Sanitization of English Cucumber (Cucumis sativus) Packaged in Polyethylene Film.

    PubMed

    Tarek, Abdussamad R; Rasco, Barbara A; Sablani, Shyam S

    2016-06-01

    Food safety is becoming an increasing concern in the United States. This study investigated the effects of ultraviolet-C (UV-C) light as a postpackaging bactericidal treatment on the quality of English cucumber packaged in polyethylene (PE) film. Escherichia coli k-12 was used as a surrogate microbe. The microbial growth and physical properties of packaged cucumbers were analyzed during a 28-d storage period at 5 °C. Inoculating packaged cucumbers treated at 23 °C for 6 min with UV-C (560 mJ/cm(2) ) resulted in a 1.60 log CFU/g reduction. However, this treatment had no significant effect (P > 0.05) on the water vapor transmission rate or oxygen transmission rate of the PE film. Results show that UV-C light treatment delayed the loss of firmness and yellowing of English cucumber up to 28 d at 5 °C. In addition, UV-C light treatment extended the shelf life of treated cucumber 1 wk longer compared to untreated cucumbers. Electron microscopy images indicate that UV-C light treatment influences the morphology of the E. coli k-12 cells. Findings demonstrate that treating cucumbers with UV-C light following packaging in PE film can reduce bacterial populations significantly and delay quality loss. This technology may also be effective for other similarly packaged fresh fruits and vegetables. PMID:27097058

  3. 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.

  4. Approximate knowledge compilation: The first order case

    SciTech Connect

    Val, A. del

    1996-12-31

    Knowledge compilation procedures make a knowledge base more explicit so as make inference with respect to the compiled knowledge base tractable or at least more efficient. Most work to date in this area has been restricted to the propositional case, despite the importance of first order theories for expressing knowledge concisely. Focusing on (LUB) approximate compilation, our contribution is twofold: (1) We present a new ground algorithm for approximate compilation which can produce exponential savings with respect to the previously known algorithm. (2) We show that both ground algorithms can be lifted to the first order case preserving their correctness for approximate compilation.

  5. 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.

  6. 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

  7. 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. PMID:26184763

  8. Novel association of severe neonatal encephalopathy and Hirschsprung disease in a male with a duplication at the Xq28 region

    PubMed Central

    2010-01-01

    Background Hirschsprung disease (HSCR) is a neurocristopathy characterized by the absence of parasympathetic intrinsic ganglion cells in the submucosal and myenteric plexuses along a variable portion of the intestinal tract. In approximately 18% of the cases HSCR also presents with multiple congenital anomalies including recognized syndromes. Methods A combination of MLPA and microarray data analysis have been undertaken to refine a duplication at the Xq28 region. Results In this study we present a new clinical association of severe neonatal encephalopathy (Lubs syndrome) and HSCR, in a male patient carrying a duplication at the Xq28 region which encompasses the MECP2 and L1CAM genes. Conclusions While the encephalopathy has been traditionally attributed to the MECP2 gene duplication in patients with Lubs syndrome, here we propose that the enteric phenotype in our patient might be due to the dosage variation of the L1CAM protein, together with additional molecular events not identified yet. This would be in agreement with the hypothesis previously forwarded that mutations in L1CAM may be involved in HSCR development in association with a predisposing genetic background. PMID:20860806

  9. Early colonization of functional groups of microbes in the infant gut.

    PubMed

    Pham, Van T; Lacroix, Christophe; Braegger, Christian P; Chassard, Christophe

    2016-07-01

    The colonization of the infant gut is crucial for early life development. Although the composition and diversity of the infant gut microbiota (GM) has been well described at a taxonomic level, functional aspects of this ecosystem remain unexplored. In the infant gut, lactate is produced by a number of bacteria and plays an important role in the trophic chain of the fermentation process. However, little is known about the lactate-utilizing bacteria (LUB) community in infants and their impact on gut health. By combining culture-based and molecular methods, we intensively studied LUB in fecal samples of 40 healthy infants on both taxonomic and functional levels. We demonstrated metabolic cross-feeding of lactate and identified keystone species specified for lactate utilization. The interactions of such species and their metabolic outcome could have direct impacts on infant health, either beneficial (production of short chain fatty acids) or detrimental (accumulation of hydrogen or hydrogen sulfide). We identified mode of delivery as a strong determinant for lactate-producing and -utilizing bacteria levels. These findings present the early establishment of GM with a novel perspective and emphasize the importance of lactate utilization in infancy.

  10. [A large-scale survey for rare blood group screening among blood donors in Chinese over Nanjing area].

    PubMed

    Ma, Ling; Liu, Yan-Chun; Xue, Min; Wei, Peng; Tang, Rong-Cai

    2011-02-01

    The purpose of this study was to investigate the distribution of 10 rare red blood groups in Chinese Nanjing population, so as to provide compatible rare blood to patients and to create a donor data bank. Jk (a-b-) (Kidd) phenotypes were detected by urea, while H-(H), GPA-(MNS), GPC-(Gerbich), i+ (Ii) and Lub-(Lutheran) phenotypes were detected by monoclonal, polyclonal antibodies with U type 96 well microplate technology. The screening of Jsb- and k-(Kell), Fya-(Duffy), Ok-(Ok), s-(MNS) and Dib-(Digeo) phenotypes were performed by polymerase chain reaction. The results showed that 2 Jk (a-b-) out of 40337 donation samples and 3 Fy (a-b+) out of 1782 donation samples were found, while no other rare blood phenotypes (H-, GPA-, GPC-, Lub-, Ok-, s-, Jsb-, k-, Dib- and i+) were detected. It is concluded that the frequencies of Jk (a-b-) and Fya(a-b+) are 0.0049% and 0.168% respectively. No more rare blood phenotype was found in this screening.

  11. Early colonization of functional groups of microbes in the infant gut.

    PubMed

    Pham, Van T; Lacroix, Christophe; Braegger, Christian P; Chassard, Christophe

    2016-07-01

    The colonization of the infant gut is crucial for early life development. Although the composition and diversity of the infant gut microbiota (GM) has been well described at a taxonomic level, functional aspects of this ecosystem remain unexplored. In the infant gut, lactate is produced by a number of bacteria and plays an important role in the trophic chain of the fermentation process. However, little is known about the lactate-utilizing bacteria (LUB) community in infants and their impact on gut health. By combining culture-based and molecular methods, we intensively studied LUB in fecal samples of 40 healthy infants on both taxonomic and functional levels. We demonstrated metabolic cross-feeding of lactate and identified keystone species specified for lactate utilization. The interactions of such species and their metabolic outcome could have direct impacts on infant health, either beneficial (production of short chain fatty acids) or detrimental (accumulation of hydrogen or hydrogen sulfide). We identified mode of delivery as a strong determinant for lactate-producing and -utilizing bacteria levels. These findings present the early establishment of GM with a novel perspective and emphasize the importance of lactate utilization in infancy. PMID:27059115

  12. 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.

  13. Multiomics in grape berry skin revealed specific induction of the stilbene synthetic pathway by ultraviolet-C irradiation.

    PubMed

    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

    2015-05-01

    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.

  14. 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

  15. Large area radiation source for water and wastewater treatment

    NASA Astrophysics Data System (ADS)

    Mueller, Michael T.; Lee, Seungwoo; Kloba, Anthony; Hellmer, Ronald; Kumar, Nalin; Eaton, Mark; Rambo, Charlotte; Pillai, Suresh

    2011-06-01

    There is a strong desire for processes that improve the safety of water supplies and that minimize disinfection byproducts. Stellarray is developing mercury-free next-generation x-ray and UV-C radiation sources in flat-panel and pipe form factors for water and wastewater treatment applications. These new radiation sources are designed to sterilize sludge and effluent, and to enable new treatment approaches to emerging environmental concerns such as the accumulation of estrogenic compounds in water. Our UV-C source, based on cathodoluminescent technology, differs significantly from traditional disinfection approaches using mercury arc lamps or UV LEDs. Our sources accelerate electrons across a vacuum gap, converting their energy into UV-C when striking a phosphor, or x-rays when striking a metallic anode target. Stellarray's large area radiation sources for wastewater treatment allow matching of the radiation source area to the sterilization target area for maximum coverage and improved efficiency.

  16. The effects of ultraviolet radiation on the moderate halophile Halomonas elongata and the extreme halophile Halobacterium salinarum.

    PubMed

    Martin, E L; Reinhardt, R L; Baum, L L; Becker, M R; Shaffer, J J; Kokjohn, T A

    2000-02-01

    Both the moderately halophilic bacterium, Halomonas elongata, and the extremely halophilic archaea, Halobacterium salinarum, can be found in hypersaline environments (e.g., salterns). On complex media, H. elongata grows over a salt range of 0.05-5.2 M, whereas, H. salinarum multiplies over a salt range of 2.5-5.2 M. The purpose of this study was to illustrate the effect that solar (UV-A and UV-B) and germicidal radiation (UV-C) had on the growth patterns of these bacteria at varied salt concentrations. Halomonas elongata grown on a complex medium at 0.05, 1.37, and 4.3 M NaCl was found to be more sensitive to UV-A and UV-B radiation, as the salt concentration of the medium increased. Halobacterium salinarum grown on a complex medium at 3.0 and 4.3 M NaCl did not show a significant drop in viability after 39.3 kJ.m-2 of UV-A and UV-B exposure. When exposed to UV-C, H. elongata exhibited substantially more sensitivity than H. salinarum. In H. elongata, differential sensitivity to UV-C was observed. At 0.05 M NaCl, H. elongata was less sensitive to UV-C than at 1.37 and 4.3 M NaCl. Both bacteria showed some photoreactivation when incubated under visible light following both UV-A, UV-B, and UV-C exposure. Mutagenesis following UV-C exposure was demonstrated by both organisms.

  17. 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. PMID:24974390

  18. 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

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

    PubMed Central

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

    2014-01-01

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

  20. 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.

  1. Sequencing and characterization of plasmid pUIBI-1 from Bacillus thuringiensis serovar entomocidus LBIT-113.

    PubMed

    López-Meza, Joel E; Barboza-Corona, J Eleazar; Del Rincón-Castro, M Cristina; Ibarra, Jorge E

    2003-11-01

    Plasmid pUIBI-1 from Bacillus thuringiensis svr. entomocidus was sequenced and its replication mechanism analyzed. Sequence analysis revealed that pUIBI-1 contains 4671 bp and a 32% GC content. Plasmid pUIBI-1 also includes at least seven putative open reading frames (ORFs) encoding for proteins ranging from 5 to 50 kDa. ORF-1 encodes for a putative 16-kDa Rep protein, which lacks homology with proteins of similar function. ORF2 encodes for a protein of 50 kDa and shows homology with Mob proteins of plasmids pLUB1000 from Lactobacillus hilgardii (32.2%) and pGI2 from B. thuringiensis (33.7%). Detection of single-stranded DNA (ssDNA) intermediates indicated that pUIBI-1 replicates by the rolling-circle replication mechanism, as demonstrated by S1 treatment and Southern hybridization under non-denaturing conditions. PMID:14669916

  2. Dual fuel Russian urban transit buses: Economical reduced emissions. Export trade information

    SciTech Connect

    1998-01-01

    This study, conducted by Caterpillar, was funded by the US Trade and Development Agency. The scope of this project was to examine the financial and environmental aspects of introducing new alternative fuel engines to the buses of Russia`s public transportation system. The report consists of the following: (1) executive summary; (2) background/overview; (3) 3306 design, development, test; (4) electronic governed engines; (5) Moscow bus testing; (6) conclusions; (7) appendices. The appendices include: (1) Caterpillar emissions lab report; (2) dyno tests -- dual fuel data sheets; (3) 3360 horizontal engine lub tilt test; (4) 1000 hour endurance test -- engine operator sheets; (5) 1000 hour endurance test -- 250 hour check; (6) Caterpillar dual fuel electronic engines; (7) product description -- dual fuel electronic governed engines; (8) California Environmental Protection Agency -- certification of caterpillar electronic governed engines; (9) annual payback data.

  3. GMUGLE: A goal lattice constructor

    NASA Astrophysics Data System (ADS)

    Hintz, Kenneth J.

    2001-08-01

    Goal lattices are a method for ordering the goals of a system and associating with each goal the value of performing that goal in terms of how much it contributes to the accomplishment of the topmost goal of a system. This paper presents a progress report on the development of a web-based implementation of the George Mason University Goal Lattice Engine (GMUGLE). GMUGLE allows a user to interactively create goal lattices, add/delete goals, and specify their ordering relations through a web-based interface. The database portion automatically computes the GLB and LUB of pairs of goals which have been entered to form them into a lattice. Yet to be implemented is the code to input goal values, automatically apportion the values among included goals, and accrue value among the included goals.

  4. Morphometric changes during the early airway response to allergen challenge in the rat.

    PubMed

    Du, T; Xu, L J; Lei, M; Wang, N S; Eidelman, D H; Ghezzo, H; Martin, J G

    1992-10-01

    The purpose of this study was to determine the relative contributions of airway wall edema and smooth muscle contraction to the early response (ER) of allergic bronchoconstriction. Brown Norway rats, 6 to 7 wk old, were sensitized with ovalbumin (OA). Anesthetized rats were challenged with either OA or saline 2 wk later. Pulmonary resistance (RL) was measured every minute until either it increased to 150% of the baseline, defined as a significant ER, or until 15 min elapsed. Eight OA-challenged test rats with a significant ER and eight saline-challenged control rats were used for morphometric studies. The lungs were quick-frozen with liquid nitrogen, processed with freeze substitution, and sagittal sections (5 microns) were stained with hematoxylin and eosin. The airway lumen subtended by the epithelial basement membrane (LuB) and cross sectional airway wall area (AW) of all airways were measured by camera lucida and digitization. The LuB and AW of each airway was standardized for size by dividing by the ideal airway lumen (LuBideal), which was calculated from the length of basement membrane, assuming a perfect circle in the unconstricted state. The cumulative frequency distribution of the LuB/LuBideal for the airways from test rats was shifted to the left compared with the control rats (p less than 0.01), indicating airway narrowing after challenge. Airway narrowing increased as a function of airway size. Cumulative frequency distributions of AW/LuBideal showed that there was a significant increase in the wall thickness of only the small airways of test animals.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1416393

  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. Investigation of the stabilization and preservation of sweet sorghum juices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sweet sorghum juice is extremely vulnerable to microbial spoilage during storage because of its high water activity and rich sugar medium, and this represents a major technical challenge. The effects of clarification (80ºC; limed to pH 6.5;5 ppm polyanionic flocculant) and UV-C irradiation were inve...

  8. 76 FR 20669 - Oreck Corporation; Analysis of Proposed Consent Order To Aid Public Comment

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-13

    ... UV-C light is effective against germs, bacteria, dust mites, mold and viruses embedded in carpets... all germs, bacteria, dust mites, molds, viruses or allergens from a user's floor; and (4) will eliminate any percent or numerical quantity of germs, bacteria, dust mites, molds, viruses or allergens...

  9. 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...

  10. Human mediator MED17 subunit plays essential roles in gene regulation by associating with the transcription and DNA repair machineries.

    PubMed

    Kikuchi, Yuko; Umemura, Hiroyasu; Nishitani, Saori; Iida, Satoshi; Fukasawa, Rikiya; Hayashi, Hiroto; Hirose, Yutaka; Tanaka, Aki; Sugasawa, Kaoru; Ohkuma, Yoshiaki

    2015-03-01

    In eukaryotes, holo-Mediator consists of four modules: head, middle, tail, and CDK/Cyclin. The head module performs an essential function involved in regulation of RNA polymerase II (Pol II). We studied the human head module subunit MED17 (hMED17). Recent structural studies showed that yeast MED17 may function as a hinge connecting the neck and movable jaw regions of the head module to the fixed jaw region. Luciferase assays in hMED17-knockdown cells showed that hMED17 supports transcriptional activation, and pulldown assays showed that hMED17 interacted with Pol II and the general transcription factors TFIIB, TBP, TFIIE, and TFIIH. In addition, hMED17 bound to a DNA helicase subunit of TFIIH, XPB, which is essential for both transcription and nucleotide excision repair (NER). Because hMED17 associates with p53 upon UV-C irradiation, we treated human MCF-7 cells with either UV-C or the MDM2 inhibitor Nutlin-3. Both treatments resulted in accumulation of p53 in the nucleus, but hMED17 remained concentrated in the nucleus in response to UV-C. hMED17 colocalized with the NER factors XPB and XPG following UV-C irradiation, and XPG and XPB bound to hMED17 in vitro. These findings suggest that hMED17 may play essential roles in switching between transcription and NER.

  11. 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. PMID:27537346

  12. 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...

  13. 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...

  14. Superhydrophobic photocatalytic surfaces through direct incorporation of titania nanoparticles into a polymer matrix by aerosol assisted chemical vapor deposition.

    PubMed

    Crick, Colin R; Bear, Joseph C; Kafizas, Andreas; Parkin, Ivan P

    2012-07-10

    A new class of superhydrophobic photocatalytic surfaces that are self-cleaning through light-induced photodegradation and the Lotus effect are presented. The films are formed in a single-step aerosol-assisted chemical vapor deposition (AACVD) process. The films are durable and show no degradation on continuous exposure to UV-C radiation. PMID:22706974

  15. 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...

  16. 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.

  17. 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)

  18. 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.

  19. 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...

  20. 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

  1. 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

  2. An enhancing effect of visible light and UV radiation on phenolic compounds and various antioxidants in broad bean seedlings

    PubMed Central

    Hasaneen, Mohammed Naguib Abdel-Ghany; Abdel-Aziz, Heba Mahmoud Mohammed

    2010-01-01

    Exposure of dark- or ambient visible light-grown broad bean seedlings to low (LL) and high (HL) visible light intensities, UV-A or UV-C, either alone or in combination, induced significant increases in total phenolic compounds as well as in anthocyanins content, throughout the germination period, as compared with the respective levels in control seedlings. In general, as compared with control levels, exposure of both dark- or light-grown broad bean seedlings to LL, HL, UV-A or UV-C, induced significant increases in the contents of non-enzymatic antioxidants (total ascorbate; ASA-DASA and total glutathione; GSSG-GSH) and enzymatic antioxidant activities (superoxide dismutase; SOD, catalase; CAT, ascorbate peroxidase; APO and glutathione reductase; GR). The obtained results are discussed in relation to induced mechanisms of protection and repair from the inevitable exposure to damaging visible light and UV radiation. PMID:20505357

  3. Human Embryonic Stem Cells have Enhanced Repair of Multiple Forms of DNA Damage

    PubMed Central

    Maynard, Scott; Swistikowa, Anna Maria; Lee, Jae Wan; Liu, Ying; Liu, Su-Ting; CRUZ, AlEXANDRE DA; Rao, Mahendra; de Souza-Pinto, Nadja; Zeng, Xianmin; Bohr, Vilhelm A.

    2008-01-01

    Embryonic stem cells need to maintain genomic integrity so they can retain the ability to differentiate into multiple cell types without propagating DNA errors. Previous studies suggest that mechanisms of genome surveillance, including DNA repair, are superior in mouse embryonic stem cells compared to various differentiated murine cells. Using single cell gel electrophoresis (comet assay) we found that human embryonic stem cells (BG01, I6) have more efficient repair of different types of DNA damage (generated from H2O2, UV-C, ionizing radiation or psoralen) than human primary fibroblasts (WI-38, hs27), and, with the exception of UV-C damage, HeLa cells. Microarray gene expression analysis showed that mRNA levels of several DNA repair genes are elevated in human embryonic stem cells compared to their differentiated forms (embryoid bodies). These data suggest that genomic maintenance pathways are enhanced in human embryonic stem cells, relative to differentiated human cells. PMID:18566332

  4. Partial Factors in Modelling of Steel Structures Reliability According to Eurocodes / Współczynniki Częściowe W Eurokodowym Modelu Niezawodności Konstrukcji Stalowych

    NASA Astrophysics Data System (ADS)

    Stachura, Zbigniew; Giżejowski, Marian

    2015-03-01

    Problems associated with the estimation of partial factors for structural systems, subsystems and buckling of individual elements are dealt with in this paper. Aspects related to resistance factors for the section resistance and member resistance are in particular referred to. The Eurocode's approach of resistance partial factor calibration assisted by experimental data for subframe systems is also summarized. Stan graniczny nośności konstrukcji, projektowanej w tradycyjnym podejściu na podstawie efektów oddziaływań jest oceniany z niezawodnościowego modelu szeregowego. Kalibrację współczynników częściowych do nośności przeprowadza się wówczas na podstawie analizy niezawodności pojedynczego elementu konstrukcji (pręta lub węzła). Eurokod stalowy [4] wprowadził zasady projektowania bazujące na bardziej złożonych modelach nośności niż w [8], gdyż stan graniczny można ocenić na podstawie warunku stateczności technicznej podukładu konstrukcji lub w ogólności, jak przedstawia to warunek (2.1) - na podstawie punktu granicznego na ścieżce równowagi wyznaczonej dla nieidealnego modelu całej konstrukcji. Pojawia się pytanie, czy stosowanie do nośności wyznaczonej na podstawie bardziej złożonych modeli mechaniki konstrukcji współczynników częściowych wyspecyfikowanych do oceny nośności pojedynczych elementów prowadzi do bezpiecznych oszacowań. Kalibracja współczynników częściowych w metodzie stanów granicznych może być dokonana przy różnych założeniach wyjściowych. Model niezawodności i ogólne zasady przyjętego w eurokodach rozdziału docelowego wskaźnika niezawodności na składowe odnoszące się do ustalenia obliczeniowych oddziaływań i ich kombinacji oraz do ustalania nośności obliczeniowej zostały podane w eurokodzie [1]. W artykule przedstawiono zagadnienia dotyczące przyjęcia współczynników częściowych do nośności układu lub podukładu konstrukcyjnego. Opisano eurokodową procedur

  5. 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. PMID:20222548

  6. Detrimental effects of UV-B radiation in a xeroderma pigmentosum-variant cell line.

    PubMed

    Herman, Kimberly N; Toffton, Shannon; McCulloch, Scott D

    2014-06-01

    DNA polymerase η (pol η), of the Y-family, is well known for its in vitro DNA lesion bypass ability. The most well-characterized lesion bypassed by this polymerase is the cyclobutane pyrimidine dimer (CPD) caused by ultraviolet (UV) light. Historically, cellular and whole-animal models for this area of research have been conducted using UV-C (λ=100-280 nm) owing to its ability to generate large quantities of CPDs and also the more structurally distorting 6-4 photoproduct. Although UV-C is useful as a laboratory tool, exposure to these wavelengths is generally very low owing to being filtered by stratospheric ozone. We are interested in the more environmentally relevant wavelength range of UV-B (λ=280-315 nm) for its role in causing cytotoxicity and mutagenesis. We evaluated these endpoints in both a normal human fibroblast control line and a Xeroderma pigmentosum variant cell line in which the POLH gene contains a truncating point mutation, leading to a nonfunctional polymerase. We demonstrate that UV-B has similar but less striking effects compared to UV-C in both its cytotoxic and its mutagenic effects. Analysis of the mutation spectra after a single dose of UV-B shows that a majority of mutations can be attributed to mutagenic bypass of dipyrimidine sequences. However, we do note additional types of mutations with UV-B that are not previously reported after UV-C exposure. We speculate that these differences are attributed to a change in the spectra of photoproduct lesions rather than other lesions caused by oxidative stress. PMID:24549972

  7. 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. PMID:27148167

  8. A radiometry protocol for UVGI fixtures using a moving-mirror type gonioradiometer.

    PubMed

    Zhang, John; Levin, Robert; Angelo, Robert; Vincent, Richard; Brickner, Philip; Ngai, Peter; Nardell, Edward A

    2012-01-01

    Ultraviolet germicidal irradiation (UVGI), 254 nm UV-C, is increasingly used as an infection control strategy to reduce the spread of airborne pathogens such as tuberculosis (TB), influenza viruses, and measles. With the appearance of multidrug-resistant TB and emerging infectious disease such as severe acute respiratory syndrome (SARS) and H1N1 influenza viruses, engineering controls using 254 nm UV-C lamps within specialized luminaires, herein designated UVGI fixtures, are being installed in high-risk settings such as homeless shelters, hospitals, jails and prisons, and schools. Studies have established that a relatively uniform spatial distribution of UV-C in the upper room can effectively cleanse the air of aerosolized pathogens. However, for planning purposes, the placement of multiple UVGI fixtures in a space, to achieve uniformity of UV-C energy distribution using currently available lighting software, is not yet practical because no industry-wide standard method exists for radiometric measurement of commercial UVGI fixtures. In this article, standard methods for photometry and reporting of general fluorescent lighting luminaire photometric data are adopted to provide UVGI fixture spatial emission distribution data in an electronic file format. The ultimate expectation of the authors is that the results will lead to a software program for fixture placement, comparable to and as easy to use as the corresponding software used for general interior lighting applications. To accomplish this goal, a radiometry measurement system is developed to obtain the radiant intensity distributions of UVGI fixtures in a three-dimensional space. This system includes a moving-mirror Type C goniometer, a mirror, a radiometer, a desktop computer, the mechanical control hardware, and the data acquisition/presentation software. Repeated measurements were made on each of three exemplary UVGI fixtures, and measurement variation did not exceed ± 2.0%.

  9. Detrimental Effects of UV-B Radiation in a Xeroderma Pigmentosum-Variant Cell Line

    PubMed Central

    Herman, Kimberly N.; Toffton, Shannon; McCulloch, Scott D.

    2014-01-01

    DNA polymerase η (pol η), of the Y-family, is well known for its in vitro DNA lesion bypass ability. The most well-characterized lesion bypassed by this polymerase is the cyclobutane pyrimidine dimer (CPD) caused by ultraviolet (UV) light. Historically, cellular and whole-animal models for this area of research have been conducted using UV-C (λ = 100–280 nm) owing to its ability to generate large quantities of CPDs and also the more structurally distorting 6-4 photoproduct. Although UV-C is useful as a laboratory tool, exposure to these wavelengths is generally very low owing to being filtered by stratospheric ozone. We are interested in the more environmentally relevant wavelength range of UV-B (λ = 280–315 nm) for its role in causing cytotoxicity and mutagenesis. We evaluated these endpoints in both a normal human fibroblast control line and a Xeroderma pigmentosum variant cell line in which the POLH gene contains a truncating point mutation, leading to a nonfunctional polymerase. We demonstrate that UV-B has similar but less striking effects compared to UV-C in both its cytotoxic and its mutagenic effects. Analysis of the mutation spectra after a single dose of UV-B shows that a majority of mutations can be attributed to mutagenic bypass of dipyrimidine sequences. However, we do note additional types of mutations with UV-B that are not previously reported after UV-C exposure. We speculate that these differences are attributed to a change in the spectra of photoproduct lesions rather than other lesions caused by oxidative stress. PMID:24549972

  10. Efficacy of an Automated Multiple Emitter Whole-Room Ultraviolet-C Disinfection System Against Coronaviruses MHV and MERS-CoV.

    PubMed

    Bedell, Kurt; Buchaklian, Adam H; Perlman, Stanley

    2016-05-01

    Efficient and automated methods of disinfecting surfaces contaminated with the Middle Eastern respiratory syndrome coronavirus (MERS-CoV) may prevent the spread of the virus. Here we report the efficacy and use of an automated triple-emitter whole room UV-C disinfection system to inactivate mouse hepatitis virus, strain A59 (MHV-A59) and MERS-CoV viruses on surfaces with a >5 log10 reduction.

  11. 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.

  12. Decontamination of targeted pathogens from patient rooms using an automated ultraviolet-C-emitting device.

    PubMed

    Anderson, Deverick J; Gergen, Maria F; Smathers, Emily; Sexton, Daniel J; Chen, Luke F; Weber, David J; Rutala, William A

    2013-05-01

    OBJECTIVE. To determine the effectiveness of an automated ultraviolet-C (UV-C) emitter against vancomycin-resistant enterococci (VRE), Clostridium difficile, and Acinetobacter spp. in patient rooms. DESIGN. Prospective cohort study. SETTING. Two tertiary care hospitals. PARTICIPANTS. Convenience sample of 39 patient rooms from which a patient infected or colonized with 1 of the 3 targeted pathogens had been discharged. INTERVENTION. Environmental sites were cultured before and after use of an automated UV-C-emitting device in targeted rooms but before standard terminal room disinfection by environmental services. RESULTS. In total, 142 samples were obtained from 27 rooms of patients who were colonized or infected with VRE, 77 samples were obtained from 10 rooms of patients with C. difficile infection, and 10 samples were obtained from 2 rooms of patients with infections due to Acinetobacter. Use of an automated UV-C-emitting device led to a significant decrease in the total number of colony-forming units (CFUs) of any type of organism (1.07 log10 reduction; P < .0001), CFUs of target pathogens (1.35 log10 reduction; P < .0001), VRE CFUs (1.68 log10 reduction; P < .0001), and C. difficile CFUs (1.16 log10 reduction; P < .0001). CFUs of Acinetobacter also decreased (1.71 log10 reduction), but the trend was not statistically significant (P = .25). CFUs were reduced at all 9 of the environmental sites tested. Reductions similarly occurred in direct and indirect line of sight. CONCLUSIONS. Our data confirm that automated UV-C-emitting devices can decrease the bioburden of important pathogens in real-world settings such as hospital rooms.

  13. Sorting through the Wealth of Options: Comparative Evaluation of Two Ultraviolet Disinfection Systems

    PubMed Central

    Nerandzic, Michelle M.; Fisher, Christopher W.; Donskey, Curtis J.

    2014-01-01

    Background Environmental surfaces play an important role in the transmission of healthcare-associated pathogens. Because environmental cleaning is often suboptimal, there is a growing demand for safe, rapid, and automated disinfection technologies, which has lead to a wealth of novel disinfection options available on the market. Specifically, automated ultraviolet-C (UV-C) devices have grown in number due to the documented efficacy of UV-C for reducing healthcare-acquired pathogens in hospital rooms. Here, we assessed and compared the impact of pathogen concentration, organic load, distance, and radiant dose on the killing efficacy of two analogous UV-C devices. Principal Findings The devices performed equivalently for each impact factor assessed. Irradiation delivered for 41 minutes at 4 feet from the devices consistently reduced C. difficile spores by ∼ 3 log10CFU/cm2, MRSA by>4 log10CFU/cm2, and VRE by >5 log10CFU/cm2. Pathogen concentration did not significantly impact the killing efficacy of the devices. However, both a light and heavy organic load had a significant negative impacted on the killing efficacy of the devices. Additionally, increasing the distance to 10 feet from the devices reduced the killing efficacy to ≤3 log10CFU/cm2 for MRSA and VRE and <2 log10CFU/cm2 for C.difficile spores. Delivery of reduced timed doses of irradiation particularly impacted the ability of the devices to kill C. difficile spores. MRSA and VRE were reduced by >3 log10CFU/cm2 after only 10 minutes of irradiation, while C. difficile spores required 40 minutes of irradiation to achieve a similar reduction. Conclusions The UV-C devices were equally effective for killing C. difficile spores, MRSA, and VRE. While neither device would be recommended as a stand-alone disinfection procedure, either device would be a useful adjunctive measure to routine cleaning in healthcare facilities. PMID:25247783

  14. 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.

  15. 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

  16. 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).

  17. 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.

  18. 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.

  19. Flares and habitability

    NASA Astrophysics Data System (ADS)

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

    2012-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    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.

  1. 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. PMID:24946032

  2. 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.

  3. 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. PMID:27664645

  4. Identification and stability of a new bichalcone in Achyrocline satureioides spray dried powder.

    PubMed

    Holzschuh, M H; Gosmann, G; Schneider, P H; Schapoval, E E S; Bassani, V L

    2010-09-01

    A new chemical structure, the 4,2',4",2'''-tetrahydroxy-6',6'''-dimethoxy-4'-O-4'''- bichalcone, named achyrobichalcone was isolated and identified from an Achyrocline satureioides spray-dried powder (SDP80). The thermal and photo stability of this new compound as well as that of the main polyphenols present in the spray dried powder, quercetin, luteolin, 3-O-metylquercetin and the corresponding kinetics of degradation are reported. In the long-term testing (30 +/- 2 degrees C/75 +/- 5% RH, 12 months), the total polyphenols contained in SDP80 demonstrated to be stable, remaining higher than 90% after a 12 month exposure. The photo stability testing revealed that all polyphenols were stable for 48 h when SDP80 was conditioned in amber or transparent flasks and exposed to UV-C radiation (light express LE UV, 254 nm, 30W). In contrast, when unprotected, the polyphenols demonstrated to be sensitive to both, thermal stress testing (80 +/- 2 degrees C), for 14 days and to UV-C radiation. Luteolin showed to be the most stable against UVC light and 3-O-methylquercetin against temperature. The achyrobichalcone demonstrated to be the more unstable against both, temperature and light. The kinetics of polyphenol thermal degradation (80 +/- 2 degrees C, 49 days) and photodegradation (UV-C radiation, 96 h) followed, 2nd and 1st order reaction, respectively.

  5. 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).

  6. 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. PMID:27038734

  7. Photochemical degradation of triazine herbicides - comparison of homogeneous and heterogeneous photocatalysis.

    PubMed

    Klementova, Sarka; Zlamal, Martin

    2013-04-01

    Photochemical degradation of atrazine under different conditions was studied and compared, namely degradation via photocatalysis on TiO2, UV C photolysis, and homogeneous photocatalysis in the presence of added ferric ions. The reaction rate constants in heterogeneous photocatalytic reactions on TiO2 and of photolytic degradation by means of UV C light are similar, 0.018 min(-1) and 0.020 min(-1), respectively. The reaction rate constants in homogeneous photocatalytic reactions with Fe(III) added depend strongly on the Fe(III) concentration, 0.0017 min(-1) for 1.6 × 10(-6) mol l(-1) Fe(III) to 0.105 min(-1) for 3.3 × 10(-4) mol l(-1) Fe(III). In all types of reactions, dechlorination was observed; in homogeneous photocatalytic reactions and in UV C (250-300 nm) photolysis, dechlorination proceeds with a 1 : 1 stoichiometry to atrazine degradation, in photocatalytic reactions on TiO2, dechlorination measured as chloride ion release reaches only 1/5 of the substrate degradation. In photocatalytic reactions on TiO2, mineralisation of 40% carbon was observed.

  8. 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.

  9. 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.

  10. Effects of forespore-specific overexpression of apurinic/apyrimidinic endonuclease Nfo on the DNA-damage resistance properties of Bacillus subtilis spores.

    PubMed

    Barraza-Salas, Marcelo; Ibarra-Rodríguez, Juan R; Mellado, Silvia J; Salas-Pacheco, José M; Setlow, Peter; Pedraza-Reyes, Mario

    2010-01-01

    The effects of overexpression of the apurinic/apyrimidinic DNA endonuclease Nfo on wet and dry heat and UV-C (254 nm) resistance of Bacillus subtilis spores with or without alpha/beta-type small, acid-soluble spore proteins (SASP) were determined. Results revealed that overexpression of Nfo > or =50-fold in spores increased the wet heat resistance of exoA nfo B. subtilis spores (termed alpha(-)beta(-)) that lack most alpha/beta-type SASP, but had no effect on these spores' UV-C resistance. Nfo overexpression also increased these spores' dry heat resistance, and to levels slightly greater than that of wild-type spores. These results are consistent: (1) with wet and dry heat (but not UV-C) generating abasic sites in alpha(-)beta(-) spore DNA; (2) with dry heat generating some of these lesions in spores that retain alpha/beta-type SASP; and (3) indicate that Nfo can repair these abasic lesions following spore germination.

  11. Alternative excision repair of ultraviolet B- and C-induced DNA damage in dormant and developing spores of Bacillus subtilis.

    PubMed

    Ramírez-Guadiana, Fernando H; Barraza-Salas, Marcelo; Ramírez-Ramírez, Norma; Ortiz-Cortés, Mayte; Setlow, Peter; Pedraza-Reyes, Mario

    2012-11-01

    The nucleotide excision repair (NER) and spore photoproduct lyase DNA repair pathways are major determinants of Bacillus subtilis spore resistance to UV radiation. We report here that a putative ultraviolet (UV) damage endonuclease encoded by ywjD confers protection to developing and dormant spores of B. subtilis against UV DNA damage. In agreement with its predicted function, a His(6)-YwjD recombinant protein catalyzed the specific incision of UV-irradiated DNA in vitro. The maximum expression of a reporter gene fusion to the ywjD opening reading frame occurred late in sporulation, and this maximal expression was dependent on the forespore-specific RNA polymerase sigma factor, σ(G). Although the absence of YwjD and/or UvrA, an essential protein of the NER pathway, sensitized developing spores to UV-C, this effect was lower when these cells were treated with UV-B. In contrast, UV-B but not UV-C radiation dramatically decreased the survival of dormant spores deficient in both YwjD and UvrA. The distinct range of lesions generated by UV-C and UV-B and the different DNA photochemistry in developing and dormant spores may cause these differences. We postulate that in addition to the UvrABC repair system, developing and dormant spores of B. subtilis also rely on an alternative excision repair pathway involving YwjD to deal with the deleterious effects of various UV photoproducts.

  12. Ultraviolet-C Irradiation: A Novel Pasteurization Method for Donor Human Milk

    PubMed Central

    Christen, Lukas; Lai, Ching Tat; Hartmann, Ben; Hartmann, Peter E.; Geddes, Donna T.

    2013-01-01

    Background Holder pasteurization (milk held at 62.5°C for 30 minutes) is the standard treatment method for donor human milk. Although this method of pasteurization is able to inactivate most bacteria, it also inactivates important bioactive components. Therefore, the objective of this study was to investigate ultraviolet irradiation as an alternative treatment method for donor human milk. Methods Human milk samples were inoculated with five species of bacteria and then UV-C irradiated. Untreated and treated samples were analysed for bacterial content, bile salt stimulated lipase (BSSL) activity, alkaline phosphatase (ALP) activity, and fatty acid profile. Results All five species of bacteria reacted similarly to UV-C irradiation, with higher dosages being required with increasing concentrations of total solids in the human milk sample. The decimal reduction dosage was 289±17 and 945±164 J/l for total solids of 107 and 146 g/l, respectively. No significant changes in the fatty acid profile, BSSL activity or ALP activity were observed up to the dosage required for a 5-log10 reduction of the five species of bacteria. Conclusion UV-C irradiation is capable of reducing vegetative bacteria in human milk to the requirements of milk bank guidelines with no loss of BSSL and ALP activity and no change of FA. PMID:23840820

  13. 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.

  14. Previous physicochemical stress exposures influence subsequent resistance of Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes to ultraviolet-C in coconut liquid endosperm beverage.

    PubMed

    Gabriel, Alonzo A

    2015-05-18

    This study investigated the influences of prior exposures to common physicochemical stresses encountered by microorganisms in food and food processing ecologies such as acidity, desiccation, and their combinations, on their subsequent susceptibility towards UV-C treatment in coconut liquid endosperm beverage. Cocktails of Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes were separately subjected to gradually acidifying environment (final pH 4.46), exposed to abrupt desiccation by suspension in saturated NaCl solution (aw=0.85) for 4, 8, and 24h, and sequential acidic and desiccated stresses before suspending in the coconut beverage for UV-C challenge. The exposure times (D) and UV-C energy dose values (DUV-C) necessary to reduce 90% of the population of the different test organisms varied with previous exposures to different sublethal stresses, indicating possible influence of implicit microbial factors towards resistance to UV-C. All tested individual and combined stresses resulted in increased resistance, albeit some were not statistically significant. Non-stressed cells had D values of 3.2-3.5s, and corresponding DUV-C values of 8.4-9.1 mJ/cm(2). Cells exposed to previous acid stress had D values of 4.1-4.8s and corresponding DUV-C values of 10.7-12.5 mJ/cm(2). Prior exposure to desiccation resulted in D values of 5.6-7.9s and DUV-C values of 14.7-20.6 mJ/cm(2), while exposure to combined acid and desiccation stresses resulted in D values of 6.1-8.1s and DUV-C values of 15.9-21.0 mJ/cm(2). The D and DUV-C values of S. enterica after previous exposure to sequential acid (24 h) and desiccation (24 h) stresses were found significantly greatest, making the organism and physiological state an appropriate reference organism for the establishment of UV-C pasteurization process for the beverage.

  15. 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.

  16. 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

  17. Previous physicochemical stress exposures influence subsequent resistance of Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes to ultraviolet-C in coconut liquid endosperm beverage.

    PubMed

    Gabriel, Alonzo A

    2015-05-18

    This study investigated the influences of prior exposures to common physicochemical stresses encountered by microorganisms in food and food processing ecologies such as acidity, desiccation, and their combinations, on their subsequent susceptibility towards UV-C treatment in coconut liquid endosperm beverage. Cocktails of Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes were separately subjected to gradually acidifying environment (final pH 4.46), exposed to abrupt desiccation by suspension in saturated NaCl solution (aw=0.85) for 4, 8, and 24h, and sequential acidic and desiccated stresses before suspending in the coconut beverage for UV-C challenge. The exposure times (D) and UV-C energy dose values (DUV-C) necessary to reduce 90% of the population of the different test organisms varied with previous exposures to different sublethal stresses, indicating possible influence of implicit microbial factors towards resistance to UV-C. All tested individual and combined stresses resulted in increased resistance, albeit some were not statistically significant. Non-stressed cells had D values of 3.2-3.5s, and corresponding DUV-C values of 8.4-9.1 mJ/cm(2). Cells exposed to previous acid stress had D values of 4.1-4.8s and corresponding DUV-C values of 10.7-12.5 mJ/cm(2). Prior exposure to desiccation resulted in D values of 5.6-7.9s and DUV-C values of 14.7-20.6 mJ/cm(2), while exposure to combined acid and desiccation stresses resulted in D values of 6.1-8.1s and DUV-C values of 15.9-21.0 mJ/cm(2). The D and DUV-C values of S. enterica after previous exposure to sequential acid (24 h) and desiccation (24 h) stresses were found significantly greatest, making the organism and physiological state an appropriate reference organism for the establishment of UV-C pasteurization process for the beverage. PMID:25723813

  18. 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. PMID:26468603

  19. 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.

  20. 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

  1. Human erythrocyte antigens. Regulation of expression of a novel erythrocyte surface antigen by the inhibitor Lutheran In(Lu) gene.

    PubMed Central

    Telen, M J; Eisenbarth, G S; Haynes, B F

    1983-01-01

    Our study describes a novel human erythrocyte protein antigen, the expression of which is regulated by the rare Lutheran inhibitor In(Lu) gene. We have produced a monoclonal antibody (A3D8) that bound strongly to erythrocytes from subjects with Lutheran phenotypes Lu(a+b+), Lu(a+b-), and Lu(a-b+) but bound negligibly to erythrocytes from subjects with the dominant form of Lu(a-b-) phenotype, reflecting inheritance of the In(Lu) gene. Importantly, erythrocytes from an individual with the recessive form of Lu(a-b-) phenotype (i.e., absence of the In(Lu) gene and absence of genes encoding for Lutheran antigens) showed reactivity with A3D8 antibody comparable to that seen with Lu(a+) or Lu(b+) erythrocytes. A3D8 antigen activity was also found on all leukocytes and in serum and plasma; this activity also appeared to be regulated by the In(Lu) gene in serum, plasma, and on a subset of leukocytes. Thus, we have identified a human erythrocyte protein whose expression is modified by the In(Lu) gene. This knowledge that such an antigen exists on erythrocytes and in normal plasma should allow further studies into the molecular genetics of the In(Lu) gene and into the functional and structural significance of the A3D8 antigen. PMID:6863545

  2. 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.

  3. [Gene polymorphism and dyslipidemias].

    PubMed

    Czajka, Magdalena; Rachubik, Patrycja; Rzeszutek, Justyna; Matysiak, Magdalena; Kruszewski, Marcin; Kapka-Skrzypczak, Lucyna

    2015-12-15

    Dyslipidemie to szerokie spektrum zaburzeń, charakteryzujące się nieprawidłowym stężeniem i/lub składem lipoprotein w surowicy krwi. Objawy te mogą towarzyszyć wtórnie innym chorobom, ale najczęściej mamy do czynienia z dyslipidemiami pierwotnymi, będącymi wynikiem interakcji czynników środowiskowych oraz predyspozycji genetycznych. W opracowaniu dokonano podsumowania stanu wiedzy na temat genetycznego podłoża dyslipidemii. Dotychczas polimorfizmy genowe skutkujące zaburzeniami lipidowymi opisano dla genów kodujących apolipoproteiny, białka receptorowe odpowiedzialne za transport lipoprotein do komórek, białka transportujące cholesterol z komórek obwodowych, białka transportujące estry cholesterolu i enzymy szlaku syntezy cholesterolu. W pracy przedstawiona została krótka charakterystyka tych genów i kodowanych przez nie białek oraz ich związek ze stężeniem lipidów we krwi.

  4. A chicken-sized crane precursor from the early Oligocene of France.

    PubMed

    Mayr, Gerald

    2005-08-01

    A skeleton of a chicken-sized crane precursor is described from the Lower Oligocene of the Lubéron in Southern France. Parvigrus pohli gen. et sp. nov. is the most substantial Paleogene fossil record of the Grues (Aramidae [limpkin] + Gruidae [cranes]), and among its oldest representatives. The fossil species is classified in the new taxon Parvigruidae, which is shown to be the sister group of extant Grues. It is the first fossil record of a stem lineage representative of the Grues and, among others, differs from modern Grues in its smaller size, shorter beak, and rail-like limb proportions. Size increase in the stem lineage of the Gruidae may be related to the spread of grasslands during the Oligocene and Miocene. Occurrence of stem lineage Grues in the Lower Oligocene of Europe is in concordance with the fact that there is no evidence for the presence of crown group members of modern avian "families" in pre-Oligocene fossil deposits.

  5. Determination of Zalcitabine in Medicaments by Differential Pulse Voltammetry

    PubMed Central

    Leandro, Katia Christina; Moreira, Josino Costa; Farias, Pércio Augusto Mardini

    2013-01-01

    The zalcitabine (ddC) has been extensively used in the treatment of HIV patients due to its antiretroviral activity. The quality control of this active principle in medications is of outstanding importance to public health. The principal objective of the current study was the development of an alternative analytical methodology for the zalcitabine determination using a voltammetric process. The zalcitabine gives a reduction peak (at −1.22 V versus Ag/AgCl) at the hanging mercury drop electrode (HMDE). The differential pulse voltammetric response is evaluated with respect to the scan rate (20 mV/s), pulse amplitude (50 mV), support electrolyte (Clark-Lubs buffer), pH (2.0), and other variables. The response is linear over the 10.0 to 28.0 mg/L (47 to 133 μM) concentration range, and the detection limit is 2.08 mg/L. The validation of this method was realized using a governmental Brazilian document (Inmetro, 2007) and the results are reported for medication drugs. PMID:26555981

  6. Simple, Rapid and Inexpensive Quantitative Fluorescent PCR Method for Detection of Microdeletion and Microduplication Syndromes

    PubMed Central

    Stofanko, Martin; Gonçalves-Dornelas, Higgor; Cunha, Pricila Silva; Pena, Heloísa B.; Vianna-Morgante, Angela M.; Pena, Sérgio Danilo Junho

    2013-01-01

    Because of economic limitations, the cost-effective diagnosis of patients affected with rare microdeletion or microduplication syndromes is a challenge in developing countries. Here we report a sensitive, rapid, and affordable detection method that we have called Microdeletion/Microduplication Quantitative Fluorescent PCR (MQF-PCR). Our procedure is based on the finding of genomic regions with high homology to segments of the critical microdeletion/microduplication region. PCR amplification of both using the same primer pair, establishes competitive kinetics and relative quantification of amplicons, as happens in microsatellite-based Quantitative Fluorescence PCR. We used patients with two common microdeletion syndromes, the Williams-Beuren syndrome (7q11.23 microdeletion) and the 22q11.2 microdeletion syndromes and discovered that MQF-PCR could detect both with 100% sensitivity and 100% specificity. Additionally, we demonstrated that the same principle could be reliably used for detection of microduplication syndromes, by using patients with the Lubs (MECP2 duplication) syndrome and the 17q11.2 microduplication involving the NF1 gene. We propose that MQF-PCR is a useful procedure for laboratory confirmation of the clinical diagnosis of microdeletion/microduplication syndromes, ideally suited for use in developing countries, but having general applicability as well. PMID:23620743

  7. Carnosine ameliorates lens protein turbidity formations by inhibiting calpain proteolysis and ultraviolet C-induced degradation.

    PubMed

    Liao, Jiahn-Haur; Lin, I-Lin; Huang, Kai-Fa; Kuo, Pei-Ting; Wu, Shih-Hsiung; Wu, Tzu-Hua

    2014-06-25

    Carnosine (CAR) is an endogenous peptide and present in lens, but there is little evidence for its effectiveness in calpain-induced proteolysis inhibition and its differential effects toward different wavelengths of ultraviolet (UV) irradiation. This study aimed to develop three in vitro cataract models to compare the mechanisms underlying the protective activities of CAR. Crude crystallins extracted from porcine lenses were used for antiproteolysis assays, and purified γ-crystallins were used for anti-UV assays. The turbidity in those in vitro models mimics cataract formation and was assayed by measuring optical density (OD) at 405 nm. The effectiveness of CAR on calpain-induced proteolysis was studied at 37 and 58 °C. Patterns of proteins were then analyzed by SDS-PAGE. The turbidity was reduced significantly (p<0.05) at 60 min measurements with the increased concentration of CAR (10-300 mM). SDS-PAGE showed that the decreased intensities at both ∼28 and ∼30 kDa protein bands in heat-enhanced assays were ameliorated by CAR at ≥10 mM concentrations. In UV-B studies, CAR (200, 300 mM) reduced the turbidity of γ-crystallin significantly (p<0.05) at 6 h observations. The turbidity of samples containing γ-crystallins was ameliorated while incubated with CAR (100, 300 mM) significantly (p<0.05) following 4 h of exposure to UV-C. SDS-PAGE showed that the presence of CAR reduced UV-B-induced aggregation of γ-crystallins at ∼44 kDa and resulted in less loss of γ-crystallin following UV-C exposure. The result of modeling also suggests that CAR acts as an inhibitor of calpain. In conclusion, CAR protects lens proteins more readily by inhibiting proteolysis and UV-C-induced degradation than aggregation induced by UV-B irradiation.

  8. 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.

  9. 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

  10. 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

  11. Evaluation of a pulsed xenon ultraviolet disinfection system for reduction of healthcare-associated pathogens in hospital rooms.

    PubMed

    Nerandzic, Michelle M; Thota, Priyaleela; Sankar C, Thriveen; Jencson, Annette; Cadnum, Jennifer L; Ray, Amy J; Salata, Robert A; Watkins, Richard R; Donskey, Curtis J

    2015-02-01

    OBJECTIVE To determine the effectiveness of a pulsed xenon ultraviolet (PX-UV) disinfection device for reduction in recovery of healthcare-associated pathogens. SETTING Two acute-care hospitals. METHODS We examined the effectiveness of PX-UV for killing of Clostridium difficile spores, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE) on glass carriers and evaluated the impact of pathogen concentration, distance from the device, organic load, and shading from the direct field of radiation on killing efficacy. We compared the effectiveness of PX-UV and ultraviolet-C (UV-C) irradiation, each delivered for 10 minutes at 4 feet. In hospital rooms, the frequency of native pathogen contamination on high-touch surfaces was assessed before and after 10 minutes of PX-UV irradiation. RESULTS On carriers, irradiation delivered for 10 minutes at 4 feet from the PX-UV device reduced recovery of C. difficile spores, MRSA, and VRE by 0.55±0.34, 1.85±0.49, and 0.6±0.25 log10 colony-forming units (CFU)/cm2, respectively. Increasing distance from the PX-UV device dramatically reduced killing efficacy, whereas pathogen concentration, organic load, and shading did not. Continuous UV-C achieved significantly greater log10CFU reductions than PX-UV irradiation on glass carriers. On frequently touched surfaces, PX-UV significantly reduced the frequency of positive C. difficile, VRE, and MRSA culture results. CONCLUSIONS The PX-UV device reduced recovery of MRSA, C. difficile, and VRE on glass carriers and on frequently touched surfaces in hospital rooms with a 10-minute UV exposure time. PX-UV was not more effective than continuous UV-C in reducing pathogen recovery on glass slides, suggesting that both forms of UV have some effectiveness at relatively short exposure times.

  12. 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. PMID:27338670

  13. 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.

  14. Complete genome sequence of Geodermatophilus obscurus type strain (G-20).

    PubMed

    Ivanova, Natalia; Sikorski, Johannes; Jando, Marlen; Munk, Christine; Lapidus, Alla; Glavina Del Rio, Tijana; Copeland, Alex; Tice, Hope; Cheng, Jan-Fang; Lucas, Susan; Chen, Feng; Nolan, Matt; Bruce, David; Goodwin, Lynne; Pitluck, Sam; Mavromatis, Konstantinos; Mikhailova, Natalia; Pati, Amrita; Chen, Amy; Palaniappan, Krishna; Land, Miriam; Hauser, Loren; Chang, Yun-Juan; Jeffries, Cynthia D; Meincke, Linda; Brettin, Thomas; Detter, John C; Rohde, Manfred; Göker, Markus; Bristow, Jim; Eisen, Jonathan A; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C; Klenk, Hans-Peter

    2010-01-01

    Geodermatophilus obscurus Luedemann 1968 is the type species of the genus, which is the type genus of the family Geodermatophilaceae. G. obscurus is of interest as it has frequently been isolated from stressful environments such as rock varnish in deserts, and as it exhibits interesting phenotypes such as lytic capability of yeast cell walls, UV-C resistance, strong production of extracellular functional amyloid (FuBA) and manganese oxidation. This is the first completed genome sequence of the family Geodermatophilaceae. The 5,322,497 bp long genome with its 5,161 protein-coding and 58 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.

  15. 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

  16. [Are children from resort spa healthy? The overweight and obesity in children from Kudowa-Zdrój].

    PubMed

    Połubok, Joanna; Gonera, Aleksandra; Ubysz, Jakub; Wójcik, Maria; Kozicka, Marta; Barg, Ewa

    2015-12-15

    Nadwaga i otyłość jest coraz częstszym problemem również wśród dzieci i młodzieży. Cel pracy. Celem pracy jest ocena rozwoju dzieci i młodzieży z Kudowy-Zdroju oraz ocena częstości występowania nadwagi i otyłości w badanej populacji w zależności od zastosowanego wskaźnika. Materiały i metody. Grupę badaną stanowiło 545 osób w wieku 5–16 lat (śr. 10,06±2,68), uczniów Szkoły Podstawowej oraz Gimnazjum w Kudowie Zdrój. Oceniono następujące parametry antropometryczne: masę i wysokość ciała, BMI, wskaźnik Queteleta, wskaźnik Rohrera, obwód talii, obwód bioder, wskaźnik talia/wysokość (WHtR). Badane parametry przedstawiono w wartościach SDS ze względu na rozpiętość wieku. Wyniki. Nadwagę lub otyłość na podstawie BMI SDS ( wartość >1,6) stwierdzono u 26,7% dzieci z klas 0–3, 22,02% dzieci z klas 4–6 oraz 22,52% gimnazjalistów. Średnie wyższe wartości BMI SDS wykazywali uczniowie klas 0–3 (śr. 0,95±2,17) w porównaniu do uczniów klas 4–6 (śr. 0,37±1,71) oraz gimnazjalistów (śr.0,65±1,61),(p=0,023). Wartości wskaźnika Rohrera SDS wskazujące na nadwagę lub otyłość stwierdzono u 22,84% dzieci, natomiast dla wskaźnika Queteleta SDS u 17,13% dzieci. Podwyższone wartości dla obwodu bioder SDS stwierdzono u 19,48% dzieci, a dla obwodu talii SDS u 17,5% dzieci. W grupie dzieci z nadwagą i otyłością u 59,4% stwierdzono podwyższone wartości obwodu talii SDS oraz u 53,4% podwyższone wartości obwodu bioder SDS. Wskaźnik WHtR był podwyższony u 8,3% dzieci, częściej u chłopców (p<0,001), odpowiednio u 3,1% dziewczynek oraz u 13,07% chłopców. Wnioski. BMI jest najczulszym wskaźnikiem określającym nadwagę i otyłość. Nadwaga i otyłość jest częstym zaburzeniem wśród dzieci z Kudowy Zdroju. Zalecana jest edukacja uczniów i ich rodzin w zakresie zdrowego stylu życia w celu zredukowania występowania nadwagi i otyłości.

  17. 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.

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

    PubMed

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

    2013-02-13

    In this study, the effect of UV irradiation (UV-A, UV-B, and UV-C) on phytochemicals, total phenolics, and antioxidant activity of postharvest pigeon pea leaves was evaluated. The response of pigeon pea leaves to UV irradiation was phytochemical specific. UV-B and UV-C induced higher levels of phytochemicals, total phenolics, and antioxidant activity in pigeon pea leaves compared with UV-A. Furthermore, UV-B irradiation proved to possess a long-lasting effect on the levels of phenolics and antioxidant activity. After adapting for 48 h at 4 °C following 4 h UV-B irradiation, total phenolics and antioxidant activity were approximately 1.5-fold and 2.2-fold increased from 39.4 mg GAE/g DM and 15.0 μmol GAE/g DM to 59.1 mg GAE/g DM and 32.5 μmol GAE/g DM, respectively. These results indicate that UV irradiation of pigeon pea leaves can be beneficial in terms of increasing active components and antioxidant activity. PMID:23320913

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

    SciTech Connect

    Applegate, L.A.; Goldberg, L.H.; Ley, R.D.; Ananthaswamy, H.N. )

    1990-02-01

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

  20. 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

  1. 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.

  2. UV habitability and dM stars: an approach for evaluation of biological survival

    NASA Astrophysics Data System (ADS)

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

    2010-02-01

    Dwarf M stars comprise about 75 percent of all stars in the galaxy. For several years planets orbiting M stars have been discarded as suitable places for development of life. This paradigm now has changed and terrestrial-type planets within liquid-water habitable zones (LW-HZ) around M stars are reconsidered as possible hosts for life as we know it. Nevertheless, large amount of UV radiation is emitted during flares by this stars, and it is uncertain how these events could affect biological systems. In particular UV-C λ < 290nm) exhibits the most damaging effects for living organisms. To analyze the hypothesis that UV could set a limit for the development of extraterrestrial life, we studied the effect of UV-C treatment on halophile archaea cultures. Halophile archaea are extremophile organisms, they are exposed to intense solar UV radiation in their natural environment so they are generally regarded as relatively UV tolerant. Halophiles inhabits in hipersaline environments as salt lakes but also have been found in ancient salt deposits as halites and evaporites on Earth. Since evaporites have been detected in Martian meteorites, these organisms are proposed as plausible inhabitants of Mars-like planets. Our preliminary results show that even after UV damage, the surviving cells were able to resume growth with nearly normal kinetics.

  3. 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.

  4. 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}.

  5. Dependence of transformation product formation on pH during photolytic and photocatalytic degradation of ciprofloxacin.

    PubMed

    Salma, Alaa; Thoröe-Boveleth, Sven; Schmidt, Torsten C; Tuerk, Jochen

    2016-08-01

    Ciprofloxacin (CIP) is a broad-spectrum antibiotic with five pH dependent species in aqueous medium, which makes its degradation behavior difficult to predict. For the identification of transformation products and prediction of degradation mechanisms, a new experimental concept making use of isotopically labeled compounds together with high resolution mass spectrometry was successfully established. The utilization of deuterated ciprofloxacin (CIP-d8) facilitated the prediction of three different degradation pathways and the corresponding degradation products, four of which were identified for the first time. Moreover, two molecular structures of previously reported transformation products were revised according to the mass spectra and product ion spectra of the deuterated transformation products. Altogether, 18 transformation products have been identified during the photolytic and photocatalytic reactions at different pH values (3, 5, 7 and 9). In this work the influence of pH on both reaction kinetics and degradation mechanism was investigated for direct ultraviolet photolysis (UV-C irradiation) and photocatalysis (TiO2/UV-C). It could be shown that the removal rates strongly depended on pH with highest removal rates at pH 9. A comparison with those at pH 3 clearly indicated that under acidic conditions ciprofloxacin cannot be easily excited by UV irradiation. We could confirm that the first reaction step for both oxidative treatment processes is mainly defluorination, followed by degradation at the piperazine ring of CIP.

  6. 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.

  7. 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

  8. Fluid flow in a spiral device used for irradiation of biological fluids.

    PubMed

    Nikolof, Todd; Prakash, Mahesh; Cleary, Paul W; Bertolini, Joseph

    2013-01-01

    The manufacture of plasma-derived therapeutics includes dedicated viral inactivation steps to minimize the risk of infection. Traditional viral inactivation methods are effective for the removal and inactivation of enveloped viruses, but less effective against small nonenveloped viruses. UV-C irradiation has been demonstrated to be an effective means of inactivating such viruses. The UVivatec lab system consists of a spiral tube around an UV-C irradiation source. Flow of a solution through the chamber generates and ensures controlled mixing and uniform exposure to irradiation. A detailed assessment of the effect of flow rate, alternate cross sectional design and scale up of the irradiation chamber on Dean vortices was performed using the smoothed particle hydrodynamics method. The aim was to provide a basis for setting flow rate limits and using a laboratory scale apparatus to model viral inactivation in larger manufacturing scale equipment. The effect of flow rate related changes on the fluence rate was also investigated through chemical actinometry studies. The data were consistent with the simulations indicating that Dean vortices were present at low flow rates, but dissipated at higher flow rates through the spiral chamber. Importantly, this work also allowed a correlation between the small system and large scale system to be established. This will greatly facilitate process development and viral validation studies. PMID:23225788

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

    PubMed

    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

  10. UV-ABC screens of luteolin derivatives compared to edelweiss extract.

    PubMed

    Fischer, Fabian; Zufferey, Evelyne; Bourgeois, Jean-Marc; Héritier, Julien; Micaux, Fabrice

    2011-04-01

    Pure luteolin is a remarkably heat (200°C/6 days) and UV stable UV-A screen, however, native luteolin enriched to 37% in an edelweiss extract lost its UV-A screen properties upon UV irradiation (∼4MJm(-2)). This contrasting behavior led to the examination of a series of purified luteolin derivatives as UV screen candidates. 3',4',5,7-Tetralipoyloxyflavones were synthesized from luteolin (3',4',5,7-tetrahydroxyflavone) and fatty acid chlorides. These acylated semi-biomolecules show a hypsochromic shift in UV-Vis spectra of about Δλ(A→B)=58nm and absorbed in the centre of the harmful UV-B band (λ(max)=295nm). Luteolin was also hydroxyethylated with Br(CH(2))(2)OH. This substitution has no effect on the λ(max)=330nm absorption of luteolin (UV-A band). Finally the natural 4'-O-β-glucosyl-3',5,7-trihydroxyflavone was extracted from edelweiss and used as a purified natural benchmark. Glycosylated and hydroxyethylated luteolin are both UV stable. Fully acylated luteolin derivatives degrade upon UV exposure to a stable UV-C screen with a hypsochroic shift Δλ(B→C)=35nm. All in all, three molecular structures based on luteolin with sunscreen properties were found, distinguishable in: UV-A, UV-B, and UV-C filters. The natural product based UV-absorbers show promise as alternatives to synthetic molecules and nanoparticles in sunscreen products.

  11. Evidence for the association of ultraviolet-C and H(2)O(2)-induced apoptosis with acid sphingomyelinase activation.

    PubMed

    Komatsu, M; Takahashi, T; Abe, T; Takahashi, I; Ida, H; Takada, G

    2001-08-29

    Ceramide appears to be a potent second messenger implicated in the regulation of diverse cellular processes such as cell growth and differentiation, gene transcription, ligand binding, and cell death. Environmental stress-induced apoptosis is believed to be associated with the sphingomyelin degradation pathway, which generates ceramide as a second messenger in initiating the apoptosis response. To date, two distinct sphingomyelinases, a lysosomal acid sphingomyelinase (ASM), which is deficient in patients affected with types A and B Niemann-Pick disease (NPD), and a neutral, magnesium-dependent sphingomyelinase (NSM), are candidate enzymes which respond to apoptotic stimulations and cause sphingomyelin hydrolysis and subsequent ceramide generation. Using Epstein-Barr virus (EBV)-transformed lymphoblast cells from type A NPD patient which have defined splicing site mutation in the ASM gene, we showed that ASM-deficient cells were defective in ultraviolet-C (UV-C) and hydrogen peroxide (H(2)O(2)) induced apoptosis. As another induction of apoptosis, we exposed this cell line to serum starvation which influences to p53 expression and leads to apoptosis. There were no differences by the degree of apoptosis between ASM-deficient lymphoblast cells and normal lymphoblast cells. These results are evidence that ASM plays one of the important roles in apoptosis induction by UV-C and H(2)O(2).

  12. 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

  13. Human ISWI complexes are targeted by SMARCA5 ATPase and SLIDE domains to help resolve lesion-stalled transcription

    PubMed Central

    Aydin, Özge Z.; Marteijn, Jurgen A.; Ribeiro-Silva, Cristina; Rodríguez López, Aida; Wijgers, Nils; Smeenk, Godelieve; van Attikum, Haico; Poot, Raymond A.; Vermeulen, Wim; Lans, Hannes

    2014-01-01

    Chromatin compaction of deoxyribonucleic acid (DNA) presents a major challenge to the detection and removal of DNA damage. Helix-distorting DNA lesions that block transcription are specifically repaired by transcription-coupled nucleotide excision repair, which is initiated by binding of the CSB protein to lesion-stalled RNA polymerase II. Using live cell imaging, we identify a novel function for two distinct mammalian ISWI adenosine triphosphate (ATP)-dependent chromatin remodeling complexes in resolving lesion-stalled transcription. Human ISWI isoform SMARCA5/SNF2H and its binding partners ACF1 and WSTF are rapidly recruited to UV-C induced DNA damage to specifically facilitate CSB binding and to promote transcription recovery. SMARCA5 targeting to UV-C damage depends on transcription and histone modifications and requires functional SWI2/SNF2-ATPase and SLIDE domains. After initial recruitment to UV damage, SMARCA5 re-localizes away from the center of DNA damage, requiring its HAND domain. Our studies support a model in which SMARCA5 targeting to DNA damage-stalled transcription sites is controlled by an ATP-hydrolysis-dependent scanning and proofreading mechanism, highlighting how SWI2/SNF2 chromatin remodelers identify and bind nucleosomes containing damaged DNA. PMID:24990377

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

    PubMed

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

    2013-02-13

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

  15. 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.

  16. The RecA-Dependent SOS Response Is Active and Required for Processing of DNA Damage during Bacillus subtilis Sporulation.

    PubMed

    Ramírez-Guadiana, Fernando H; Barajas-Ornelas, Rocío Del Carmen; Corona-Bautista, Saúl U; Setlow, Peter; Pedraza-Reyes, Mario

    2016-01-01

    The expression of and role played by RecA in protecting sporulating cells of Bacillus subtilis from DNA damage has been determined. Results showed that the DNA-alkylating agent Mitomycin-C (M-C) activated expression of a PrecA-gfpmut3a fusion in both sporulating cells' mother cell and forespore compartments. The expression levels of a recA-lacZ fusion were significantly lower in sporulating than in growing cells. However, M-C induced levels of ß-galactosidase from a recA-lacZ fusion ~6- and 3-fold in the mother cell and forespore compartments of B. subtilis sporangia, respectively. Disruption of recA slowed sporulation and sensitized sporulating cells to M-C and UV-C radiation, and the M-C and UV-C sensitivity of sporangia lacking the transcriptional repair-coupling factor Mfd was significantly increased by loss of RecA. We postulate that when DNA damage is encountered during sporulation, RecA activates the SOS response thus providing sporangia with the repair machinery to process DNA lesions that may compromise the spatio-temporal expression of genes that are essential for efficient spore formation.

  17. A photochemical reactor for studies of atmospheric chemistry

    NASA Astrophysics Data System (ADS)

    Nilsson, E. J. K.; Eskebjerg, C.; Johnson, M. S.

    A photochemical reactor for studies of atmospheric kinetics and spectroscopy has been built at the Copenhagen Center for Atmospheric Research. The reactor consists of a vacuum FTIR spectrometer coupled to a 100 L quartz cylinder by multipass optics mounted on electropolished stainless steel end flanges, surrounded by UV-A, UV-C and broadband sun lamps in a temperature-controlled housing. The combination of a quartz vessel and UV-C lamps allows higher concentrations of O( 1D) and OH than can be generated by similar chambers. The reactor is able to produce radical concentrations of ca. 8 × 10 11 cm -3 for OH, 3 × 10 6 cm -3 for O( 1D), 3.3 × 10 10 cm -3 for O( 3P) and 1.6 × 10 12 cm -3 for Cl. The reactor can be operated at pressures from 10 -3 to 10 3 mbar and temperatures from 240 to 330 K. As a test of the system we have studied the reaction CHCl 3 + Cl using the relative rate technique and find k CHCl3+Cl/k CH4+Cl = 1.03 ± 0.11, in good agreement with the accepted value.

  18. The RecA-Dependent SOS Response Is Active and Required for Processing of DNA Damage during Bacillus subtilis Sporulation

    PubMed Central

    Corona-Bautista, Saúl U.; Setlow, Peter; Pedraza-Reyes, Mario

    2016-01-01

    The expression of and role played by RecA in protecting sporulating cells of Bacillus subtilis from DNA damage has been determined. Results showed that the DNA-alkylating agent Mitomycin-C (M-C) activated expression of a PrecA-gfpmut3a fusion in both sporulating cells’ mother cell and forespore compartments. The expression levels of a recA-lacZ fusion were significantly lower in sporulating than in growing cells. However, M-C induced levels of ß-galactosidase from a recA-lacZ fusion ~6- and 3-fold in the mother cell and forespore compartments of B. subtilis sporangia, respectively. Disruption of recA slowed sporulation and sensitized sporulating cells to M-C and UV-C radiation, and the M-C and UV-C sensitivity of sporangia lacking the transcriptional repair-coupling factor Mfd was significantly increased by loss of RecA. We postulate that when DNA damage is encountered during sporulation, RecA activates the SOS response thus providing sporangia with the repair machinery to process DNA lesions that may compromise the spatio-temporal expression of genes that are essential for efficient spore formation. PMID:26930481

  19. 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.

  20. 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

  1. Transcriptional responses to biologically relevant doses of UV-B radiation in the model archaeon, Halobacterium sp. NRC-1

    PubMed Central

    Boubriak, Ivan; Ng, Wooi Loon; DasSarma, Priya; DasSarma, Shiladitya; Crowley, David J; McCready, Shirley J

    2008-01-01

    Background Most studies of the transcriptional response to UV radiation in living cells have used UV doses that are much higher than those encountered in the natural environment, and most focus on short-wave UV (UV-C) at 254 nm, a wavelength that never reaches the Earth's surface. We have studied the transcriptional response of the sunlight-tolerant model archaeon, Halobacterium sp. NRC-1, to low doses of mid-wave UV (UV-B) to assess its response to UV radiation that is likely to be more biologically relevant. Results Halobacterium NRC-1 cells were irradiated with UV-B at doses equivalent to 30 J/m2 and 5 J/m2 of UV-C. Transcriptional profiling showed that only 11 genes were up-regulated 1.5-fold or more by both UV-B doses. The most strongly up-regulated gene was radA1 (vng2473), the archaeal homologue of RAD51/recA recombinase. The others included arj1 (vng779) (recJ-like exonuclease), top6A (vng884) and top6B (vng885) (coding for Topoisomerase VI subunits), and nrdJ (vng1644) (which encodes a subunit of ribonucleotide reductase). We have found that four of the consistently UV-B up-regulated genes, radA1 (vng2473), vng17, top6B (vng885) and vng280, share a common 11-base pair motif in their promoter region, TTTCACTTTCA. Similar sequences were found in radA promoters in other halophilic archaea, as well as in the radA promoter of Methanospirillum hungatei. We analysed the transcriptional response of a repair-deficient ΔuvrA (vng2636) ΔuvrC (vng2381) double-deletion mutant and found common themes between it and the response in repair proficient cells. Conclusion Our results show a core set of genes is consistently up-regulated after exposure to UV-B light at low, biologically relevant doses. Eleven genes were up-regulated, in wild-type cells, after two UV-B doses (comparable to UV-C doses of 30 J/m2 and 5 J/m2), and only four genes were up-regulated by all doses of UV-B and UV-C that we have used in this work and previously. These results suggest that high doses

  2. 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

  3. A new series of pillared uranyl-vanadates based on uranophane-type sheets in the uranium-vanadium-linear alkyl diamine systems

    SciTech Connect

    Jouffret, Laurent; Rivenet, Murielle; Abraham, Francis

    2010-01-15

    A new family of three-dimensional (3D) uranyl vanadates (C{sub 3}N{sub 2}H{sub 12}){l_brace}[(UO{sub 2})(H{sub 2}O)][(UO{sub 2})(VO{sub 4})]{sub 4}{r_brace}.1H{sub 2}O (C3UV), (C{sub 4}N{sub 2}H{sub 14}){l_brace}[(UO{sub 2})(H{sub 2}O)][(UO{sub 2})(VO{sub 4})]{sub 4}{r_brace}.2H{sub 2}O (C4UV), (C{sub 5}N{sub 2}H{sub 16}) {l_brace}[(UO{sub 2})(H{sub 2}O)][(UO{sub 2})(VO{sub 4})]{sub 4}{r_brace} (C5UV), (C{sub 6}N{sub 2}H{sub 20}) {l_brace}[(UO{sub 2})(H{sub 2}O)][(UO{sub 2})(VO{sub 4})]{sub 4}{r_brace} (C6UV) and (C{sub 7}N{sub 2}H{sub 22}) {l_brace}[(UO{sub 2})(H{sub 2}O)][(UO{sub 2})(VO{sub 4})]{sub 4}{r_brace} (C7UV) was prepared from mild-hydrothermal reactions using 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane and 1,7-diaminoheptane as structure directing agents. The five compounds are orthorhombic, space group Cmc2{sub 1}, with a{approx}15.6, b{approx}14.1, c{approx}13.6 A. The structures were solved using single-crystal X-ray diffraction data. The compounds contain the same three-dimensional inorganic framework built from uranyl-vanadate layers of uranophane-type anion topology pillared by [UO{sub 6}(H{sub 2}O)] pentagonal bipyramids. The doubly protonated diamines reside in the cavities created by the inorganic framework and are linked to the inorganic framework through hydrogen bonds involving one nitrogen atom. The structure is compared with that of uranyl-phosphates and uranyl-arsenates containing alkaline metals. The use of alkaline metals for the synthesis of uranyl-vanadates leads to carnotite-type compounds. - Graphical abstract: The (C{sub 6}N{sub 2}H{sub 20}){l_brace}[(UO{sub 2})(H{sub 2}O)][(UO{sub 2})(VO{sub 4})]{sub 4}{r_brace} compound: projection in the (1 0 0) and in the (0 0 1) planes showing the amine position.

  4. Transcriptional profile of the homologous recombination machinery and characterization of the EhRAD51 recombinase in response to DNA damage in Entamoeba histolytica

    PubMed Central

    López-Casamichana, Mavil; Orozco, Esther; Marchat, Laurence A; López-Camarillo, César

    2008-01-01

    Background In eukaryotic and prokaryotic cells, homologous recombination is an accurate mechanism to generate genetic diversity, and it is also used to repair DNA double strand-breaks. RAD52 epistasis group genes involved in recombinational DNA repair, including mre11, rad50, nsb1/xrs2, rad51, rad51c/rad57, rad51b/rad55, rad51d, xrcc2, xrcc3, rad52, rad54, rad54b/rdh54 and rad59 genes, have been studied in human and yeast cells. Notably, the RAD51 recombinase catalyses strand transfer between a broken DNA and its undamaged homologous strand, to allow damaged region repair. In protozoan parasites, homologous recombination generating antigenic variation and genomic rearrangements is responsible for virulence variation and drug resistance. However, in Entamoeba histolytica the protozoan parasite responsible for human amoebiasis, DNA repair and homologous recombination mechanisms are still unknown. Results In this paper, we initiated the study of the mechanism for DNA repair by homologous recombination in the primitive eukaryote E. histolytica using UV-C (150 J/m2) irradiated trophozoites. DNA double strand-breaks were evidenced in irradiated cells by TUNEL and comet assays and evaluation of the EhH2AX histone phosphorylation status. In E. histolytica genome, we identified genes homologous to yeast and human RAD52 epistasis group genes involved in DNA double strand-breaks repair by homologous recombination. Interestingly, the E. histolytica RAD52 epistasis group related genes were differentially expressed before and after UV-C treatment. Next, we focused on the characterization of the putative recombinase EhRAD51, which conserves the typical architecture of RECA/RAD51 proteins. Specific antibodies immunodetected EhRAD51 protein in both nuclear and cytoplasmic compartments. Moreover, after DNA damage, EhRAD51 was located as typical nuclear foci-like structures in E. histolytica trophozoites. Purified recombinant EhRAD51 exhibited DNA binding and pairing activities and

  5. 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.

  6. 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

  7. 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.

  8. Beta-carotene suppression of benzophenone-sensitized lipid peroxidation in hexane through additional chain-breaking activities

    NASA Astrophysics Data System (ADS)

    Cvetković, Dragan; Marković, Dejan

    2011-01-01

    The aim of this work is to estimate the antioxidant activity of β-carotene in the presence of two different mixtures of phospholipids in hexane solution, under continuous UV-irradiation from three different ranges (UV-A, UV-B, and UV-C). β-Carotene is employed to control lipid peroxidation process generated by UV-irradiation, in the presence and in the absence of selected photosensitizer, benzophenone, by scavenging the involved, created free radicals. The results show that β-carotene undergoes to a substantial, probably structural dependent destruction (bleaching), highly dependent on UV-photons energy input, more expressed in the presence than in the absence of benzophenone. The additional bleaching is synchronized with the further increase in β-carotene antioxidant activity in the presence of benzophenone, implying the same cause: increase in (phospholipids peroxidation) chain-breaking activities.

  9. Astrobiological Effects of Stellar Radiation in Circumstellar Environments

    NASA Astrophysics Data System (ADS)

    Cuntz, Manfred; Gurdemir, Levent; Guinan, Edward F.; Kurucz, Robert L.

    2006-10-01

    The centerpiece of all life on Earth is carbon-based biochemistry. Previous scientific research has suggested that biochemistry based on carbon may also play a decisive role in extraterrestrial life forms, i.e., alien life outside of Earth, if existent. In the following, we explore if carbon-based macromolecules (such as DNA) in the environments of stars other than the Sun are able to survive the effects of energetic stellar radiation, such as UV-C in the wavelength band between 200 and 290 nm. We focus on main-sequence stars akin to the Sun, but of hotter (F-type stars) and cooler (K- and M-type stars) surface temperature. Emphasis is placed on investigating the radiative environment in stellar habitable zones (HZs). Stellar habitable zones have an important relevance in astrobiology because they constitute circumstellar regions in which a planet of suitable size can have surface temperatures for water to exist in liquid form.

  10. Real-time damage monitoring of irradiated DNA.

    PubMed

    Pješčić, Ilija; Tranter, Collin A; Haywood, James C; Paidipalli, Manasa; Ganveer, Ankur; Haywood, Stratton E; Tham, Jessica; Crews, Niel D

    2011-09-01

    This article presents a microfluidic technique for the real-time analysis of DNA damage due to radiation exposure. A continuous-flow spatial melting analysis was performed every three seconds on a sample of isolated DNA while it was being irradiated. The formation of photoproducts being caused by the UV-C radiation was monitored during the process. Cumulative damage produced distinct changes in the DNA melting curves, characterized by a shifting and broadening of the melting peaks. The design of the microfluidic device, the experimental procedure, and the analysis algorithm and interactive GUI are discussed herein. In addition, the advantages of this system are correlated to specific needs of related scientific studies, such as the investigation of sequence-specific damage susceptibility and the characterization of exposure-damage nonlinearities.

  11. 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. PMID:26256169

  12. The UV limits of life on extrasolar planets: an experiment with halophile archaeabacteria at different UV doses.

    NASA Astrophysics Data System (ADS)

    Abrevaya, X. C.; Adamo, H. P.; Cortó N, E.; Mauas, P. J. D.

    Terrestial-type planets around M stars are proposed as feasible places for development of life as we know it. Nevertheless many dMe stars emit large amounts of UV radiation during flares and it is unknown if these events could be deleterious for life. Since terrestrial biological systems are particularly vulnerable to this kind of radiation, this fact could set a limit for habitability. Organisms as halophile archaeabacteria were found in ancient evaporites on Earth. Evaporites have been detected in Martian meteorites, so these organisms are proposed as plausible inhabitants of Mars-like planets or other extrasolar planets. We examine the effect of UV-C on the halophile archaea Natrialba magadii. Results show that these organisms are able to survive at the UV doses tested.

  13. Plant UVR8 photoreceptor senses UV-B by tryptophan-mediated disruption of cross-dimer salt bridges.

    PubMed

    Christie, John M; Arvai, Andrew S; Baxter, Katherine J; Heilmann, Monika; Pratt, Ashley J; O'Hara, Andrew; Kelly, Sharon M; Hothorn, Michael; Smith, Brian O; Hitomi, Kenichi; Jenkins, Gareth I; Getzoff, Elizabeth D

    2012-03-23

    The recently identified plant photoreceptor UVR8 (UV RESISTANCE LOCUS 8) triggers regulatory changes in gene expression in response to ultraviolet-B (UV-B) light through an unknown mechanism. Here, crystallographic and solution structures of the UVR8 homodimer, together with mutagenesis and far-UV circular dichroism spectroscopy, reveal its mechanisms for UV-B perception and signal transduction. β-propeller subunits form a remarkable, tryptophan-dominated, dimer interface stitched together by a complex salt-bridge network. Salt-bridging arginines flank the excitonically coupled cross-dimer tryptophan "pyramid" responsible for UV-B sensing. Photoreception reversibly disrupts salt bridges, triggering dimer dissociation and signal initiation. Mutation of a single tryptophan to phenylalanine retunes the photoreceptor to detect UV-C wavelengths. Our analyses establish how UVR8 functions as a photoreceptor without a prosthetic chromophore to promote plant development and survival in sunlight.

  14. Carbamazepine degradation by photolysis and titanium dioxide photocatalysis.

    PubMed

    Im, Jong-Kwon; Son, Hyun-Seok; Kang, Young-Min; Zoh, Kyung-Duk

    2012-07-01

    We investigated the degradation of carbamazepine by photolysis/ultraviolet (UV)-C only and titanium dioxide photocatalysis. The degradation of carbamazepine by UV-only and titanium-dioxide-only (adsorption) reactions were inefficient, however, complete degradation of carbamazepine was observed by titanium dioxide photocatalysis within 30 min. The rate of degradation increased as initial carbamazepine concentration decreased, and the removal kinetics fit well with the Langmuir-Hinshelwood model. The addition of methanol, a radical scavenger, decreased carbamazepine removal, suggesting that the hydroxide radical played an important role during carbamazepine degradation. The addition of oxygen during titanium dioxide photocatalysis accelerated hydroxide radical production, thus improving mineralization activity. The photocatalytic degradation was more efficient at a higher pH, whereas the removal of carbamazepine and acridine (a major intermediate) were more efficient under aerobic conditions. The mineralization of carbamazepine during photocatalysis produced various ionic by-products such as ammonium and nitrate by way of nitrogen dioxide.

  15. 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.

  16. 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.

  17. 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.

  18. Complete genome sequence of Geodermatophilus obscurus type strain (G-20T)

    SciTech Connect

    Ivanova, N; Sikorski, Johannes; Jando, Marlen; Munk, Christine; Lapidus, Alla L.; Glavina Del Rio, Tijana; Copeland, A; Tice, Hope; Cheng, Jan-Fang; Lucas, Susan; Chen, Feng; Nolan, Matt; Bruce, David; Goodwin, Lynne A.; Pitluck, Sam; Mavromatis, K; Mikhailova, Natalia; Pati, Amrita; Chen, Amy; Palaniappan, Krishna; Land, Miriam L; Hauser, Loren John; Chang, Yun-Juan; Jeffries, Cynthia; Meincke, Linda; Detter, J. Chris; Rohde, Manfred; Goker, Markus; Bristow, James; Eisen, Jonathan; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C; Klenk, Hans-Peter

    2010-01-01

    Geodermatophilus obscurus Luedemann 1968 is the type species of the genus, which is the type genus of the family Geodermatophilaceae. G. obscurus is of interest as it has frequently been isolated from stressful environments such as rock varnish in deserts, and as it exhibits interesting phenotypes such as lytic capability of yeast cell walls, UV-C resistance, strong production of extracellular functional amyloid (FuBA) and manganese oxidation. This is the first completed genome sequence of the family Geodermatophilaceae. The 5,322,497 bp long genome with its 5,161 protein-coding and 58 RNA genes is part of the Genomic Encyc-lopedia of Bacteria and Archaea project.

  19. 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.

  20. 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. PMID:27388596

  1. Two alternatively spliced transcripts generated from OsMUS81, a rice homolog of yeast MUS81, are up-regulated by DNA-damaging treatments.

    PubMed

    Mimida, Naozumi; Kitamoto, Hiroko; Osakabe, Keishi; Nakashima, Marina; Ito, Yuji; Heyer, Wolf-Dietrich; Toki, Seiichi; Ichikawa, Hiroaki

    2007-04-01

    OsMUS81, a rice homolog of the yeast MUS81 endonuclease gene, produced two alternative transcripts, OsMUS81alpha and OsMUS81beta. OsMus81alpha contained a Helix-hairpin-Helix (HhH) motif at the N- and C-termini, and a conserved XPF-like motif in the center, while the OsMus81beta isoform lacked the second HhH motif by alternative splicing of a cryptic intron generating a truncated protein. The two transcripts were induced after DNA-damaging treatments such as high intensity light, UV-C and gamma-radiation. The yeast two-hybrid assay detected a strong interaction between OsMus81 and OsRad54 recombinational repair proteins. These findings suggest that OsMus81 functions in maintaining genome integrity through homologous recombination. PMID:17327258

  2. The regrowth of phytoplankton cultures after UV disinfection.

    PubMed

    Martínez, Lucía F; Mahamud, Manuel M; Lavín, Antonio G; Bueno, Julio L

    2013-02-15

    This study addresses how cultures of three phytoplankton species -Chaetoceros calcitrans, Chlorella autotrophica and Phaeocystis globosa - can recover from the effects of UV-C exposure if the cells are placed in a rich medium. Flow cytometry and pulse amplitude modulation (PAM) were used to determine cell recovery after UV treatment. The recovery of C. calcitrans was complete 9 days after treatment. For C. autotrophica, the recovery was noticeable 5 days after treatment. P. globosa only recovered if the UV dose did not exceed 7.3×10(5) μWs/cm(2). The recovery of the UV-treated cultures introduced to a regrowth medium, compared with the recovery of the irradiated cultures kept in their original environment, had two main characteristics: cell recovery was slower but was more efficient. This pattern of recovery has very important implications for real ballast water management systems because such systems discharge treated water into the environment.

  3. Chloroflexus aurantiacus and ultraviolet radiation: Implications for archean shallow-water stromatolites

    NASA Astrophysics Data System (ADS)

    Pierson, Beverly K.; Mitchell, Heather K.; Ruff-Roberts, Alyson L.

    1993-08-01

    The phototrophic growth ofChloroflexus aurantiacus under anoxic conditions was determined as a function of continuous UV irradiance. Cultures grown under an irradiance of 0.01 Wm-2 exhibited a slightly depressed yield over the nonirradiated control. Yields decreased further with increasing irradiance. Inhibition was severe at an irradiance of 0.66 Wm-2. Growth ofE. coli cultures was severely depressed at UV-C irradiances that permitted good growth ofC. aurantiacus. Low levels of Fe3+ provided a very effective UV absorbing screen. The apparent UV resistance ofChloroflexus and the effectiveness of iron as a UV-absorbing screen in sediments and microbial mats are suggested to be likely mechanisms of survival of early phototrophs in the Precambrian in the absence of an ozone shield.

  4. 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.

  5. 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.

  6. Reduction of deoxynivalenol contaminating corn silage by short-term ultraviolet irradiation: a pilot study.

    PubMed

    Murata, Hideo; Yamaguchi, Daisuke; Nagai, Akiko; Shimada, Nobuaki

    2011-08-01

    We evaluated the effects of short-term (up to 60 min) irradiation of corn silage with ultraviolet (UV) light (intensity: 1.5 mW/cm(2) at 254 nm UV-C wavelength), along with constant stirring of the silage, on the concentration of deoxynivalenol (DON), a major feed-contaminating mycotoxin, and those of α-tocopherol (vitamin E) and β-carotene (pro-vitamin A). The initial DON concentration in artificially contaminated silage was set at approximately 60 µg/g dry silage weight. After irradiation, the level of DON was decreased significantly (P<0.05) by approximately 13 µg/g (22%) on average at 30 min, and by 12 µg/g (21%) at 60 min. However, the concentrations of the vitamins remained relatively unaffected. Although further improvement is needed, short-term UV irradiation seems a promising on-farm method for reducing the level of DON in feedstuffs.

  7. 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

  8. 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

  9. 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).

  10. 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.

  11. 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

  12. 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

  13. Transcription coupled repair deficiency results in increased chromosomal aberrations and apoptotic death in the UV61 cell line, the Chinese hamster homologue of Cockayne's syndrome B.

    PubMed

    Proietti De Santis, L; Garcia, C L; Balajee, A S; Brea Calvo, G T; Bassi, L; Palitti, F

    2001-03-01

    Transcription coupled repair (TCR), a special sub-pathway of nucleotide excision repair (NER), removes transcription blocking lesions rapidly from the transcribing strand of active genes. In this study, we have evaluated the importance of the TCR pathway in the induction of chromosomal aberrations and apoptosis in isogenic Chinese hamster cell lines, which differ in TCR efficiency. AA8 is the parental cell line, which is proficient in the genome overall repair of UV-C radiation induced 6-4 photoproducts (6-4 PP) and the repair of cyclobutane pyrimidine dimer (CPD) from the transcribing strand of active genes. UV61 cells (hamster homologue of human Cockayne's syndrome (CS) group B cells) originally isolated from AA8, exhibit proficient repair of 6-4 PP but are deficient in CPD removal by the TCR pathway. Upon UV-C irradiation of cells in G1-phase, UV61 showed a dramatic increase in apoptotic response as compared to AA8 cells. Abolition of TCR by treatment with alpha-amanitin (an inhibitor of RNA polymerase II) in AA8 cells also resulted in an elevated apoptotic response like that observed in UV61 cells treated with UV alone. This suggests that the lack of TCR is largely responsible for increased apoptotic response in UV61 cells. Furthermore, the chromosomal aberrations and sister chromatid exchange (SCE) induced by UV were also found to be higher in UV61 cells than in TCR proficient AA8 cells. This study shows that the increased chromosomal aberrations and apoptotic death in UV61 cells is due to their inability to remove CPD from the transcribing strand of active genes and suggests a protective role for TCR in the prevention of both chromosomal aberrations and apoptosis induced by DNA damage. Furthermore, flow cytometry analysis and time-course appearance of apoptotic cells suggest that the conversion of UV-DNA damage into chromosomal aberrations precedes and determines the apoptotic process. PMID:11182543

  14. Inheritance of abnormal expression of SOS-like response in xeroderma pigmentosum and hereditary cancer-prone syndromes.

    PubMed

    Abrahams, P J; Houweling, A; Cornelissen-Steijger, D M; Arwert, F; Menko, F H; Pinedo, H M; Terleth, C; van der Eb, A J

    1996-06-01

    The time course of induction of SOS-like stress responses such as enhanced reactivation (ER) and enhanced mutagenesis (EM) has been investigated in UV-C-irradiated skin fibroblasts from a xeroderma pigmentosum (XP) family, using herpes simplex virus type 1 as a probe. Similar ER studies were performed in a Li-Fraumeni syndrome (LFS) family and in a family with a high incidence of breast, ovarian, and colon cancer. In two XP (complementation group B) patients, with a striking absence of skin tumors even at an age of >40 years, only induction of EM was observed, whereas ER was absent (XPER-). The ER- phenotype was inherited from the father, whereas cells from the mother exhibited normal expression of ER and EM. This suggests that the absence of ER is a hereditary trait that is not correlated with a repair-deficient phenotype. Abnormally high levels of ER were observed in UV-C-exposed skin fibroblasts from rive LFS patients. The inheritance of the ER response was studied in one LFS family. High levels of ER were observed only in cells derived from affected individuals carrying one mutated p53 allele, whereas cells from unaffected family members, carrying two wild-type p53 alleles, exhibited normal ER levels. This result shows that abnormally high levels of ER positively correlate with the occurrence of cancer in affected individuals from a LFS family. Interestingly, abnormally high levels of ER were observed in cells from afflicted as well as from unafflicted members of a family with a high incidence of breast, ovarian, colon, and stomach cancer. This suggests that these latter individuals have inherited a mutated, putative predisposing gene, resulting in abnormal expression of ER, but that cancer had not yet developed. The results indicate that the ER response can possibly be used as a prognostic marker to identify carriers in various hereditary cancer-prone syndromes at an early age. PMID:8653707

  15. Stress-induced biosynthesis of dicaffeoylquinic acids in globe artichoke.

    PubMed

    Moglia, Andrea; Lanteri, Sergio; Comino, Cinzia; Acquadro, Alberto; de Vos, Ric; Beekwilder, Jules

    2008-09-24

    Leaf extracts from globe artichoke ( Cynara cardunculus L. var. scolymus) have been widely used in medicine as hepatoprotectant and choleretic agents. Globe artichoke leaves represent a natural source of phenolic acids with dicaffeoylquinic acids, such as cynarin (1,3-dicaffeoylquinic acid), along with its biosynthetic precursor chlorogenic acid (5-caffeoylquinic acid) as the most abundant molecules. This paper reports the development of an experimental system to induce caffeoylquinic acids. This system may serve to study the regulation of the biosynthesis of (poly)phenolic compounds in globe artichoke and the genetic basis of this metabolic regulation. By means of HPLC-PDA and accurate mass LC-QTOF MS and MS/MS analyses, the major phenolic compounds in globe artichoke leaves were identified: four isomers of dicaffeoylquinic acid, three isomers of caffeoylquinic acid, and the flavone luteolin 7-glucoside. Next, plant material was identified in which the concentration of phenolic compounds was comparable in the absence of particular treatments, with the aim to use this material to test the effect of stress application on the regulation of biosynthesis of caffeoylquinic acids. Using this material, the effect of UV-C, methyl jasmonate, and salicylic acid treatments on (poly)phenolic compounds was tested in different globe artichoke genotypes. UV-C exposure consistently increased the levels of dicaffeoylquinic acids in all genotypes, whereas the effect on compounds from the same biosynthetic pathway, for example, chlorogenic acid and luteolin-7-glucoside, was much less pronounced and was not statistically significant. No effect of methyl jasmonate or salicylic acid was found. Time-response experiments indicated that the level of dicaffeoylquinic acids reached a maximum at 24 h after UV radiation. On the basis of these results a role of dicaffeoylquinic acids in UV protection in globe artichoke is hypothesized.

  16. 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

  17. 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. PMID:26967007

  18. Comparing three UV wavelengths for pre-exposing Gafchromic EBT2 and EBT3 films.

    PubMed

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

    2015-01-01

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

  19. Multiple transformation pathways of p-arsanilic acid to inorganic arsenic species in water during UV disinfection.

    PubMed

    Li, Suqi; Xu, Jing; Chen, Wei; Yu, Yingtan; Liu, Zizheng; Li, Jinjun; Wu, Feng

    2016-09-01

    p-Arsanilic acid (p-ASA) is widely used in China as livestock and poultry feed additive for promoting animal growth. The use of organoarsenics poses a potential threat to the environment because it is mostly excreted by animals in its original form and can be transformed by UV-Vis light excitation. This work examined the initial rate and efficiency of p-ASA phototransformation under UV-C disinfection lamp. Several factors influencing p-ASA phototransformation, namely, pH, initial concentration, temperature, as well as the presence of NaCl, NH4(+), and humic acid, were investigated. Quenching experiments and LC-MS were performed to investigate the mechanism of p-ASA phototransformation. Results show that p-ASA was decomposed to inorganic arsenic (including As(III) and As(V)) and aromatic products by UV-C light through direct photolysis and indirect oxidation. The oxidation efficency of p-ASA by direct photosis was about 32%, and those by HO and (1)O2 were 19% and 49%, respectively. Cleavage of the arsenic-benzene bond through direct photolysis, HO oxidation or (1)O2 oxidation results in simultaneous formation of inorganic As(III), As(IV), and As(V). Inorganic As(III) is oxidized to As(IV) and then to As(V) by (1)O2 or HO. As(IV) can undergo dismutation or simply react with oxygen to produce As(V) as well. Reactions of the organic moieties of p-ASA produce aniline, aminophenol and azobenzene derivatives as main products. The photoconvertible property of p-ASA implies that UV disinfection of wastewaters from poultry and swine farms containing p-ASA poses a potential threat to the ecosystem, especially agricultural environments.

  20. Efficient removal of cyclobutane pyrimidine dimers in barley: differential contribution of light-dependent and dark DNA repair pathways.

    PubMed

    Manova, Vasilissa; Georgieva, Ralitsa; Borisov, Borislav; Stoilov, Lubomir

    2016-10-01

    Barley stress response to ultraviolet radiation (UV) has been intensively studied at both the physiological and morphological level. However, the ability of barley genome to repair UV-induced lesions at the DNA level is far less characterized. In this study, we have investigated the relative contribution of light-dependent and dark DNA repair pathways for the efficient elimination of cyclobutane pyrimidine dimers (CPDs) from the genomic DNA of barley leaf seedlings. The transcriptional activity of barley CPD photolyase gene in respect to the light-growth conditions and UV-C irradiation of the plants has also been analyzed. Our results show that CPDs induced in the primary barley leaf at frequencies potentially damaging DNA at the single-gene level are removed efficiently and exclusively by photorepair pathway, whereas dark repair is hardly detectable, even at higher CPD frequency. A decrease of initially induced CPDs under dark is observed but only after prolonged incubation, suggesting the activation of light-independent DNA damage repair and/or tolerance mechanisms. The green barley seedlings possess greater capacity for CPD photorepair than the etiolated ones, with efficiency of CPD removal dependent on the intensity and quality of recovering light. The higher repair rate of CPDs measured in the green leaves correlates with the higher transcriptional activity of barley CPD photolyase gene. Visible light and UV-C radiation affect differentially the expression of CPD photolyase gene particularly in the etiolated leaves. We propose that the CPD repair potential of barley young seedlings may influence their response to UV-stress.

  1. 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

  2. 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.

  3. Stress-induced biosynthesis of dicaffeoylquinic acids in globe artichoke.

    PubMed

    Moglia, Andrea; Lanteri, Sergio; Comino, Cinzia; Acquadro, Alberto; de Vos, Ric; Beekwilder, Jules

    2008-09-24

    Leaf extracts from globe artichoke ( Cynara cardunculus L. var. scolymus) have been widely used in medicine as hepatoprotectant and choleretic agents. Globe artichoke leaves represent a natural source of phenolic acids with dicaffeoylquinic acids, such as cynarin (1,3-dicaffeoylquinic acid), along with its biosynthetic precursor chlorogenic acid (5-caffeoylquinic acid) as the most abundant molecules. This paper reports the development of an experimental system to induce caffeoylquinic acids. This system may serve to study the regulation of the biosynthesis of (poly)phenolic compounds in globe artichoke and the genetic basis of this metabolic regulation. By means of HPLC-PDA and accurate mass LC-QTOF MS and MS/MS analyses, the major phenolic compounds in globe artichoke leaves were identified: four isomers of dicaffeoylquinic acid, three isomers of caffeoylquinic acid, and the flavone luteolin 7-glucoside. Next, plant material was identified in which the concentration of phenolic compounds was comparable in the absence of particular treatments, with the aim to use this material to test the effect of stress application on the regulation of biosynthesis of caffeoylquinic acids. Using this material, the effect of UV-C, methyl jasmonate, and salicylic acid treatments on (poly)phenolic compounds was tested in different globe artichoke genotypes. UV-C exposure consistently increased the levels of dicaffeoylquinic acids in all genotypes, whereas the effect on compounds from the same biosynthetic pathway, for example, chlorogenic acid and luteolin-7-glucoside, was much less pronounced and was not statistically significant. No effect of methyl jasmonate or salicylic acid was found. Time-response experiments indicated that the level of dicaffeoylquinic acids reached a maximum at 24 h after UV radiation. On the basis of these results a role of dicaffeoylquinic acids in UV protection in globe artichoke is hypothesized. PMID:18710252

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

    PubMed

    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

  5. Efficient removal of cyclobutane pyrimidine dimers in barley: differential contribution of light-dependent and dark DNA repair pathways.

    PubMed

    Manova, Vasilissa; Georgieva, Ralitsa; Borisov, Borislav; Stoilov, Lubomir

    2016-10-01

    Barley stress response to ultraviolet radiation (UV) has been intensively studied at both the physiological and morphological level. However, the ability of barley genome to repair UV-induced lesions at the DNA level is far less characterized. In this study, we have investigated the relative contribution of light-dependent and dark DNA repair pathways for the efficient elimination of cyclobutane pyrimidine dimers (CPDs) from the genomic DNA of barley leaf seedlings. The transcriptional activity of barley CPD photolyase gene in respect to the light-growth conditions and UV-C irradiation of the plants has also been analyzed. Our results show that CPDs induced in the primary barley leaf at frequencies potentially damaging DNA at the single-gene level are removed efficiently and exclusively by photorepair pathway, whereas dark repair is hardly detectable, even at higher CPD frequency. A decrease of initially induced CPDs under dark is observed but only after prolonged incubation, suggesting the activation of light-independent DNA damage repair and/or tolerance mechanisms. The green barley seedlings possess greater capacity for CPD photorepair than the etiolated ones, with efficiency of CPD removal dependent on the intensity and quality of recovering light. The higher repair rate of CPDs measured in the green leaves correlates with the higher transcriptional activity of barley CPD photolyase gene. Visible light and UV-C radiation affect differentially the expression of CPD photolyase gene particularly in the etiolated leaves. We propose that the CPD repair potential of barley young seedlings may influence their response to UV-stress. PMID:27021252

  6. Multiple transformation pathways of p-arsanilic acid to inorganic arsenic species in water during UV disinfection.

    PubMed

    Li, Suqi; Xu, Jing; Chen, Wei; Yu, Yingtan; Liu, Zizheng; Li, Jinjun; Wu, Feng

    2016-09-01

    p-Arsanilic acid (p-ASA) is widely used in China as livestock and poultry feed additive for promoting animal growth. The use of organoarsenics poses a potential threat to the environment because it is mostly excreted by animals in its original form and can be transformed by UV-Vis light excitation. This work examined the initial rate and efficiency of p-ASA phototransformation under UV-C disinfection lamp. Several factors influencing p-ASA phototransformation, namely, pH, initial concentration, temperature, as well as the presence of NaCl, NH4(+), and humic acid, were investigated. Quenching experiments and LC-MS were performed to investigate the mechanism of p-ASA phototransformation. Results show that p-ASA was decomposed to inorganic arsenic (including As(III) and As(V)) and aromatic products by UV-C light through direct photolysis and indirect oxidation. The oxidation efficency of p-ASA by direct photosis was about 32%, and those by HO and (1)O2 were 19% and 49%, respectively. Cleavage of the arsenic-benzene bond through direct photolysis, HO oxidation or (1)O2 oxidation results in simultaneous formation of inorganic As(III), As(IV), and As(V). Inorganic As(III) is oxidized to As(IV) and then to As(V) by (1)O2 or HO. As(IV) can undergo dismutation or simply react with oxygen to produce As(V) as well. Reactions of the organic moieties of p-ASA produce aniline, aminophenol and azobenzene derivatives as main products. The photoconvertible property of p-ASA implies that UV disinfection of wastewaters from poultry and swine farms containing p-ASA poses a potential threat to the ecosystem, especially agricultural environments. PMID:27593271

  7. 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

  8. 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

  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. Modeling Atmosphere Composition and Determining Explosibility in a Sealed Coal Mine Volume

    NASA Astrophysics Data System (ADS)

    Cheng, Jianwei; Luo, Yi

    2014-03-01

    Explosions originated from or around the sealed areas in underground coal mines present a serious safety threat. The explosibility of the mine atmosphere depends on the composition of oxygen, combustible and inert gases. In additional, the composition in the inaccessible sealed areas change with time under various factors, such as gases emissions, air leakage, inert gases injected, etc. In order to improve mine safety, in this paper, a mathematical model based on the control volume approach to simulate the atmosphere compositions is developed, and the expanded Coward explosibility triangle diagram is used to assess the mine gas explosion risk. A computer program is developed to carry out the required computations and to display the results. In addition, the USBM explosibility diagram is also included in the program to serve as a double check. Wybuchy powstające wewnątrz lub wokół zamkniętych (odizolowanych) regionów w podziemnych kopalniach węgla stanowią poważne zagrożenie. Możliwość wystąpienia wybuchu powietrza kopalnianego uzależniona jest od proporcji zawartego w nim tlenu, gazów palnych i gazów obojętnych. Ponadto, skład atmosfery wewnątrz zamkniętych odizolowanych przestrzeni ulega zmianom w czasie pod wpływem różnorakich czynników: wydzielanie gazów, przecieki powietrza, doprowadzanie gazów obojętnych. Dla poprawy bezpieczeństwa pracy w kopalni opracowano model matematyczny bazujący na metodzie objętości kontrolnej dla symulacji składu powietrza. Rozszerzony wykres Cowarda wskazujący skłonność do wybuchu wykorzystany został do oszacowania ryzyka wystąpienia wybuchu gazów kopalnianych. Opracowano program komputerowy który wykonuje niezbędne obliczenia i wyświetla wyniki. Ponadto, dla dodatkowego potwierdzenia wyników wykorzystano wykres USBM obrazujący niebezpieczeństwo wybuchu

  11. Frequencies of red blood cell major blood group antigens and phenotypes in the Chinese Han population from Mainland China.

    PubMed

    Yu, Y; Ma, C; Sun, X; Guan, X; Zhang, X; Saldanha, J; Chen, L; Wang, D

    2016-08-01

    Alloantibodies directed to red blood cell (RBC) antigens play an important role in alloimmune-mediated haemolytic transfusion reactions and haemolytic disease of the foetus and newborn. The frequencies and phenotypes of RBC antigens are different in populations from different geographic areas and races. However, the data on major blood group antigens in the Chinese Han population from Mainland China are still very limited; thus, we aimed to investigate them in this study. A total of 1412 unrelated voluntary Chinese Han blood donors were randomly recruited. All donors were typed for blood group antigens: D, C, c, E, e, C(w) , Jk(a) , Jk(b) ,M, N, S, s, Le(a) , Le(b) , K, k. Kp(a) , Kp(b) , Fy(a) , Fy(b) , Lu(a) , Lu(b) , P1 and Di(a) using serological technology. Calculations of antigen and phenotype frequencies were expressed as percentages and for allele frequencies under the standard assumption of Hardy-Weinberg equilibrium. Amongst the Rh antigens, D was the most common (98.94%) followed by e (92.28%), C (88.81%), c (58.43%), E (50.78%) and C(w) (0.07%) with DCe/DCe (R1 R1 , 40.72%) being the most common phenotype. In the Kell blood group system, k was present in 100% of the donors and a rare phenotype, Kp (a+b+), was found in 0.28% of the donors. For the Kidd and Duffy blood group systems, Jk (a+b+) and Fy (a+b-) were the most common phenotypes (44.05% and 84.35%, respectively). In the MNS blood group system, M+N+S-s+ (45.54%) was the most common, whereas M+N-S-s- and M-N+S-s- were not found. The rare Lu (a-b-) and Lu (a+b+) phenotypes were identified in 0.43% and 1.13% of the donors, respectively. Le(a) and Le(b) were seen in 17.92% and 63.03% of donors, respectively. The frequency of Di(a) was 4.75%, which was higher than in the Chinese population in Taiwan region or the Caucasian and Black populations (P < 0.0001). This study systematically describes the frequencies of 24 blood group antigens in the Chinese Han population from Mainland China. The data can

  12. 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

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

    NASA Astrophysics Data System (ADS)

    Horneck, G.

    2007-08-01

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

  14. Ozonated water extends the shelf life of fresh-cut lettuce.

    PubMed

    Beltrán, David; Selma, María V; Marín, Alicia; Gil, María I

    2005-07-13

    The use of ozonated water as a sanitizer to extend the shelf life of fresh-cut lettuce and the effect on the antioxidant constituents (polyphenols and vitamin C) were investigated. Fresh-cut iceberg lettuce (Lactuca sativa L.) was washed at 4 degrees C using three different ozonated water dips [10, 20, and 10 activated by ultraviolet C (UV-C) light mg L(-1) min total ozone dose], and the dips were compared with water and chlorine rinses. Treated lettuce was packaged in air or active modified atmosphere packaging (MAP) (4 kPa of O2 + 12 kPa of CO2 balanced with N2) and stored for 13 days at 4 degrees C. Despite its strong oxidizing activity, ozonated water did not stimulate the respiratory activity of fresh-cut lettuce. Moreover, ozonated water maintained the initial visual appearance of fresh-cut lettuce and controlled browning during storage in air. Initially, ozonated water and chlorine reduced the total mesophilic population by 1.6 and 2.1 log, respectively, when compared with water. Active MAP was effective in controlling total microbial growth, achieving 2.0 log reduction in relation to samples stored in air at the end of storage. On the other hand, active MAP caused a 2.0-3.5 reduction of coliforms on sanitized samples compared with water-washed samples. The most efficient treatments were ozone 20 and ozone 10 activated by UV-C, which were as effective as chlorine. Changes in individual phenolic compounds were independent of the washing treatments. In air, chlorogenic and isochlorogenic acid contents increased noticeably after 13 days while monocaffeoyltartaric and dicaffeoyltartaric acids remained unchanged. MAP effectively suppressed accumulation of caffeoylquinic derivatives, whereas caffeoyltartaric derivatives decreased during MAP storage to reach similar levels. The content of vitamin C (ascorbic acid and dehydroascorbic acid) decreased during storage, particularly under MAP. Ozonated water could be an alternative sanitizer to chlorine for fresh

  15. A Fenton-like degradation mechanism for 1,4-dioxane using zero-valent iron (Fe0) and UV light.

    PubMed

    Son, Hyun-Seok; Im, Jong-Kwon; Zoh, Kyung-Duk

    2009-03-01

    In this study, the degradation mechanism of 1,4-dioxane using zero-valent iron (Fe0) in the presence of UV light was investigated kinetically. The degradation of 1,4-dioxane in Fe0-only, photolysis, and combined Fe0 and UV reactions followed the kinetics of a pseudo-first-order model. The degradation rate constant (19 x 10(-4)min(-1)) in the combined reaction with UV-C (4.2 mW cm(-2)) and Fe0 (5 mg L(-1)) was significantly enhanced compared to Fe0-only (4.8 x 10(-4) min(-1)) and photolytic reactions (2.25 x 10(-4)min(-1)), respectively. The removal efficiency of 1,4-dioxane in combined reaction with Fe0 and UV within 4 h was enhanced by increasing UV intensity at UV-C region (34% at 4.2 mW cm(-2) and 89% at 16.9 mW cm(-2)) comparing with the removal in the combined reaction with Fe0 and UV-A (29% at 2.1 mW cm(-2), and 33% at 12.6 mW cm(-2)). It indicates that 1,4-dioxane was degraded mostly by OH radicals in the combined reaction. The degradation patterns in both Fe(0)-only and combined reactions were well fitted to the Langmuir-Hinshelwood model, implying that adsorption as well as the chemical reaction occurred. The transformation of Fe0 to Fe2+ and Fe3+ was observed in the Fe0-only and combined reactions, and the transformation rate of Fe0 was improved by UV irradiation. Furthermore, the reduction of Fe3+ was identified in the combined reaction, and the reduction rate was enhanced by an increase of UV energy. Our study demonstrated that the enhancement of 1,4-dioxane removal rate occurred via an increased supply of OH radicals from the Fenton-like reaction induced by the photolysis of Fe0 and H2O, and with producing less sludge.

  16. Life and the solar uv environment on the early Earth

    NASA Astrophysics Data System (ADS)

    Bérces, A.; Kovács, G.; Rontó, G.; Lammer, H.; Kargl, G.; Kömle, N.; Bauer, S.

    2003-04-01

    The solar UV radiation environment on planetary surfaces and within their atmospheres is of importance in a wide range of scientific disciplines. Solar UV radiation is the driving force of chemical and organic evolution and serves also as a constraint in biological evolution. Studies of the solar UV environment of the early Earth 2.0 Gyr to 3.8 Gyr ago suggest that the terrestrial atmosphere was essentially anoxic, resulting in an ozone column abundance insufficient for protecting the planetary surface in the UV-B and the UV-C ranges. Since, short wavelength solar UV radiation in the UV-B ind UV-C range penetrated through the unprotected atmosphere to the surface on early Earth, associated biological consequences may be expected. For DNA-based terrestrial solar UV dosimetry, bacteriophage T7, isolated phage-DNA ind polycrystalline Uracil samples have been used. The effect of solar UV radiation can be measured by detecting the biological-structural consequences of the damage induced by UV photons. We show model calculations for the Biological Effective Dose (BED) rate of Uracil and bacteriophage T7, for various ozone concentrations representing early atmospheric conditions on Earth up to a UV protecting ozone layer comparable to present times. Further, we discuss experimental data which show the photo-reverse effect of Uracil molecules caused by short UV wavelengths. These photoreversion effect highly depend on the wavelength of the radiation. Shorter wavelength UV radiation of about 200 nm is strongly effective in monomerisation, while the longer wavelengths prefer the production of dimerisation. We could demonstrate experimentally, for the case of an Uracil thin-layer that the photo-reaction process of the nucleotides can be both, dimerization and the reverse process: monomerization. These results are important for the study of solar UV exposure on organisms in the terrestrial environment more than 2 Gyr ago where Earth had no UV protecting ozone layer as well as

  17. The response of the ozone layer to the solar UV input: analysis of nonlinear trends

    NASA Astrophysics Data System (ADS)

    Alberti, Tommaso; Lepreti, Fabio; Vecchio, Antonio; Carbone, Vincenzo

    2016-04-01

    The response of the climate system to different forcings is a complex and challenging problem due to the nonlinear nature of the Sun-Earth interaction mechanisms. One of these mechanisms is related to the interaction between stratospheric ozone (O3) and solar ultraviolet (UV) radiation. Indeed, stratospheric ozone mainly absorbs solar UV radiation at wavelengths into the range 120 ≤ λ ≤ 240 nm and reemits it as thermal longwave radiation (heat) which keeps the stratosphere warmer that it would otherwise be. In this work, we present the analysis of the ozone data between 1967 and 2010 through the Empirical Mode Decomposition which we use to extract a nonlinear time-dependent trend. In this way, we can investigate local acceleration and deceleration of the trend, obtaining richer informations with respect to the usual linear model. These informations can be useful for the interpretation of the long-term evolution of the stratospheric ozone layer. Moreover, the ozone trend is compared with trends referred to three bands of the solar ultraviolet radiation. We found that the decreasing ozone trend is similar to the decreasing of UV-C and UV-B bands and that their time derivatives have a minimum (corresponding to changes in acceleration/deceleration properties) about 2 years after the 22th solar cycle maximum. Moreover, we found that the ozone trend acceleration process is well correlated with the UV-B decreasing, while UV-C trend acceleration process is faster with respect the ozone one. We also note that ozone trend presents an opposite behaviour with respect to UV-A trend because this range of solar UV wavelengths is not associated with photochemical reaction processes. Finally, a time-latitude analysis of the ozone trends can be carried out showing differences between the two hemispheres. A time-latitude distribution of the ozone trends reveals the existence of an asymmetry between northern and southern hemispheres, while the mid-latitude and equatorial regions

  18. 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

  19. Registration of untypical 3D objects in Polish cadastre - do we need 3D cadastre? / Rejestracja nietypowych obiektów 3D w polskim katastrze - czy istnieje potrzeba wdrożenia katastru 3D?

    NASA Astrophysics Data System (ADS)

    Marcin, Karabin

    2012-11-01

    Polish cadastral system consists of two registers: cadastre and land register. The cadastre register data on cadastral objects (land, buildings and premises) in particular location (in a two-dimensional coordinate system) and their attributes as well as data about the owners. The land register contains data concerned ownerships and other rights to the property. Registration of a land parcel without spatial objects located on the surface is not problematic. Registration of buildings and premises in typical cases is not a problem either. The situation becomes more complicated in cases of multiple use of space above the parcel and with more complex construction of the buildings. The paper presents rules concerning the registration of various untypical 3D objects located within the city of Warsaw. The analysis of the data concerning those objects registered in the cadastre and land register is presented in the paper. And this is the next part of the author's detailed research. The aim of this paper is to answer the question if we really need 3D cadastre in Poland. Polski system katastralny składa się z dwóch rejestrów: ewidencji gruntów i budynków (katastru nieruchomosci) oraz ksiąg wieczystych. W ewidencji gruntów i budynków (katastrze nieruchomości) rejestrowane są dane o położeniu (w dwuwymiarowym układzie współrzędnych), atrybuty oraz dane o właścicielach obiektów katastralnych (działek, budynków i lokali), w księgach wieczystych oprócz danych właścicielskich, inne prawa do nieruchomości. Rejestracja działki bez obiektów przestrzennych położonych na jej powierzchni nie stanowi problemu. Także rejestracja budynków i lokali w typowych przypadkach nie stanowi trudności. Sytuacja staje się bardziej skomplikowana w przypadku wielokrotnego użytkowania przestrzeni powyzej lub poniżej powierzchni działki oraz w przypadku budynków o złożonej konstrukcji. W artykule przedstawiono zasady związane z rejestracją nietypowych obiektów 3

  20. Application of methods for area calculation of geodesic polygons on Polish administrative units / Zastosowanie metod obliczania pól powierzchni wieloboków geodezyjnych na przykładzie jednostek administracyjnych w Polsce

    NASA Astrophysics Data System (ADS)

    Pędzich, Paweł; Kuźma, Marta

    2012-11-01

    The paper presents methods of area calculation, which may be applied for big geodesic polygons on the ellipsoid. Proposal developed by the authors of this paper is discussed. The proposed methods are compared with other, alternative methods of area calculation of such polygons. Test calculations are performed for administrative units in Poland. The obtained results are also compared with areas of those units registered in statistical annals. Utilisation of the equal-area map projections of the ellipsoid onto a plane seems to be the best solution for the discussed task. In the case of small distances between points we may expect accurate results of calculations, since the area size is influenced by the projection reductions only, which are small in such cases. In some cases their influence on results of calculations may be neglected. Then, only re-calculation of co-ordinates from the GRS80 ellipsoid to the cartographic, equal-area projection is required. Umiejętność obliczania pól wieloboków geodezyjnych, czyli takich, których bokami są odcinki linii geodezyjnych, ma istotne znaczenie w praktyce geodezyjnej i kartograficznej. Jednym z podstawowych zadań wykonywanych przez geodetów i kartografów jest obliczanie pól różnych obiektów powierzchniowych takich jak gmina, województwo, obszary użytków gruntowych itp. Jeżeli zadanie sprowadza się tylko do powierzchni kuli lub płaszczyzny to rozwiązanie jest stosunkowo łatwe. Zadanie komplikuje się, jeżeli za powierzchnię odniesienia fizycznej powierzchni Ziemi przyjmiemy elipsoidę obrotową, ponieważ nie ma ścisłych wzorów, które pozwalałyby na realizację takiego zadania; są jedynie wzory przybliżone mające zastosowanie dla niewielkich obszarów. Trudności pojawiają się szczególnie w przypadku dużych wieloboków zlokalizowanych na elipsoidzie obrotowej spłaszczonej. W artykule przedstawiono metody obliczania pól powierzchni, które mogą być stosowane dla dużych wielobok

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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. PMID:11767740

  6. 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.

  7. Role of phytochromes A and B in the regulation of cell death and acclimatory responses to UV stress in Arabidopsis thaliana.

    PubMed

    Rusaczonek, Anna; Czarnocka, Weronika; Kacprzak, Sylwia; Witoń, Damian; Ślesak, Ireneusz; Szechyńska-Hebda, Magdalena; Gawroński, Piotr; Karpiński, Stanisław

    2015-11-01

    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

  8. 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.

  9. 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

  10. 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

  11. Interactions between light and vitreous fluid substitutes.

    PubMed

    Azzolini, C; Docchio, F; Brancato, R; Trabucchi, G

    1992-10-01

    To determine the interactions between light and vitreous fluid substitutes, we studied the absorption and fluorescence properties of the following fluids that are commonly used in vitreoretinal surgery: Ringer's solution, balanced salt citrate-buffered solution, balanced salt bicarbonate-buffered solution, hydroxypropyl methylcellulose ophthalmic solution, hyaluronate sodium, perfluorocarbons, silicone oil, and fluorosilicone oil. The absorption spectra for all the fluids peaked in the UV-C (reference range <280 nm) and UV-B (reference range from 315 to 280 nm) regions of the spectrum, with little or no absorption in the visible region of the spectrum (from 400 to 700 nm). Emission of almost all of the fluids occurred mainly in the 300- to 360-nm region, with fairly low-quantum efficiency. The limited light absorption properties of the fluids calls for caution during transpupillary and intraocular laser photocoagulation to avoid excessive retinal damage, mainly when the laser power is increased during treatment. Transmission of incoherent light (environmental and ophthalmic artificial light) through highly transparent vitreous fluid substitutes may lead in time to dangerous light exposure, particularly in aphakic eyes. The emitted fluorescence in these fluids generates a minimal risk of long-term damage.

  12. Correlation of Force Production with Apoptosis in Tissue Dynamics

    NASA Astrophysics Data System (ADS)

    Toyama, Yusuke; Peralta, Xomalin; Venakides, Stephanos; Kiehart, Daniel; Edwards, Glenn

    2007-03-01

    To understand embryo morphogenesis, it is necessary to know the force distribution in the various tissues. Since cells are largely inaccessible to mechanical probes in vivo, measurements of the net forces exerted by cells are challenging. The combination of experimental and theoretical approaches has proven to improve our understanding of these forces. A steerable UV-laser microbeam was used to probe the forces and the resulting kinematics were monitored with confocal microscopy. Dorsal closure is a developmental stage in Drosophila embryogenesis, where the dynamics are a consequence of four biological processes [1]. During this stage, cells that have outlived their usefulness undergo apoptosis, a biological process also known as programmed cell death for cells. Apoptotic events were decreased with genetic techniques or increased by irradiation with a UV-C lamp. We present experimental evidence for force generation correlating with apoptosis. This research has been supported by the NIH (GM33830 and GM61240). [1] M. S. Hutson, et al. Science, 300, 145 (2003).

  13. Genetics of Lipid-Storage Management in Caenorhabditis elegans Embryos.

    PubMed

    Schmökel, Verena; Memar, Nadin; Wiekenberg, Anne; Trotzmüller, Martin; Schnabel, Ralf; Döring, Frank

    2016-03-01

    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

  14. Protection of enzymes from photodegradation by entrapment within alumina.

    PubMed

    Shapovalova, Olga E; Levy, David; Avnir, David; Vinogradov, Vladimir V

    2016-10-01

    Most enzymes are highly sensitive to UV-light in all of its ranges and their activity can irreversibly drop even after a short time of exposure. Here we report a solution of this problem by using sol-gel matrices as effective protectors against this route of enzyme inactivation and denaturation. The concept presented here utilizes several modes of action: First, the entrapment within the rigid ceramic sol-gel matrix, inhibits denaturation motions, and the hydration shell around the entrapped protein provides extra protection. Second, the matrix itself - alumina in this report - absorbs UV light. And third, sol-gel materials have been shown to be quite universal in their ability to entrap small molecules, and so co-entrapment with well documented sun-screening molecules (2-hydroxybenzophenone, 2,2'-dihydroxybenzophenone, and 2,2'-dihydroxy-4-methoxybenzophenone) is an additional key protective tool. Three different enzymes as models were chosen for the experiments: carbonic anhydrase, acid phosphatase and horseradish peroxidase. All showed greatly enhanced UV (regions UV-A, UV-B, and UV-C) stabilization after entrapment within the doped sol-gel alumina matrices. PMID:27442952

  15. LEM-3 - A LEM domain containing nuclease involved in the DNA damage response in C. elegans.

    PubMed

    Dittrich, Christina M; Kratz, Katja; Sendoel, Ataman; Gruenbaum, Yosef; Jiricny, Josef; Hengartner, Michael O

    2012-01-01

    The small nematode Caenorhabditis elegans displays a spectrum of DNA damage responses similar to humans. In order to identify new DNA damage response genes, we isolated in a forward genetic screen 14 new mutations conferring hypersensitivity to ionizing radiation. We present here our characterization of lem-3, one of the genes identified in this screen. LEM-3 contains a LEM domain and a GIY nuclease domain. We confirm that LEM-3 has DNase activity in vitro. lem-3(lf) mutants are hypersensitive to various types of DNA damage, including ionizing radiation, UV-C light and crosslinking agents. Embryos from irradiated lem-3 hermaphrodites displayed severe defects during cell division, including chromosome mis-segregation and anaphase bridges. The mitotic defects observed in irradiated lem-3 mutant embryos are similar to those found in baf-1 (barrier-to-autointegration factor) mutants. The baf-1 gene codes for an essential and highly conserved protein known to interact with the other two C. elegans LEM domain proteins, LEM-2 and EMR-1. We show that baf-1, lem-2, and emr-1 mutants are also hypersensitive to DNA damage and that loss of lem-3 sensitizes baf-1 mutants even in the absence of DNA damage. Our data suggest that BAF-1, together with the LEM domain proteins, plays an important role following DNA damage - possibly by promoting the reorganization of damaged chromatin. PMID:22383942

  16. Unscheduled DNA Synthesis: The Clinical and Functional Assay for Global Genomic DNA Nucleotide Excision Repair

    PubMed Central

    Latimer, Jean J.; Kelly, Crystal M.

    2016-01-01

    The unscheduled DNA synthesis (UDS) assay measures the ability of a cell to perform global genomic nucleotide excision repair (NER). This chapter provides instructions for the application of this technique by creating 6-4 photoproducts and pyrimidine dimers using UV-C irradiation. This procedure is designed specifically for quantification of the 6-4 photoproducts. Repair is quantified by the amount of radioactive thymidine incorporated during repair synthesis after this insult, and radioactivity is evaluated by grain counting after autoradiography. The results are used to clinically diagnose human DNA repair deficiency disorders and provide a basis for investigation of repair deficiency in human tissues or tumors. No other functional assay is available that directly measures the capacity to perform NER on the entire genome without the use of specific antibodies. Since live cells are required for this assay, explant culture techniques must be previously established. Host cell reactivation (HCR), as discussed in Chapter 37, is not an equivalent technique, as it measures only transcription-coupled repair (TCR) at active genes, a small subset of total NER. PMID:24623250

  17. 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

  18. 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

    PubMed Central

    Broughton, B. C.; Thompson, A. F.; Harcourt, S. A.; Vermeulen, W.; Hoeijmakers, J. H. J.; Botta, E.; Stefanini, M.; King, M. D.; Weber, C. A.; Cole, J.; Arlett, C. F.; Lehmann, A. R.

    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→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. ImagesFigure 3Figure 5 PMID:7825573

  19. 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. PMID:26630044

  20. DNA damage and repair in plants under ultraviolet and ionizing radiations.

    PubMed

    Gill, Sarvajeet S; Anjum, Naser A; Gill, Ritu; Jha, Manoranjan; Tuteja, Narendra

    2015-01-01

    Being sessile, plants are continuously exposed to DNA-damaging agents present in the environment such as ultraviolet (UV) and ionizing radiations (IR). Sunlight acts as an energy source for photosynthetic plants; hence, avoidance of UV radiations (namely, UV-A, 315-400 nm; UV-B, 280-315 nm; and UV-C, <280 nm) is unpreventable. DNA in particular strongly absorbs UV-B; therefore, it is the most important target for UV-B induced damage. On the other hand, IR causes water radiolysis, which generates highly reactive hydroxyl radicals (OH(•)) and causes radiogenic damage to important cellular components. However, to maintain genomic integrity under UV/IR exposure, plants make use of several DNA repair mechanisms. In the light of recent breakthrough, the current minireview (a) introduces UV/IR and overviews UV/IR-mediated DNA damage products and (b) critically discusses the biochemistry and genetics of major pathways responsible for the repair of UV/IR-accrued DNA damage. The outcome of the discussion may be helpful in devising future research in the current context.

  1. 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

  2. Evidence for anti-apoptotic roles of proteasome activator 28γ via inhibiting caspase activity.

    PubMed

    Moncsek, Anja; Gruner, Melanie; Meyer, Hannes; Lehmann, Andrea; Kloetzel, Peter-Michael; Stohwasser, Ralf

    2015-09-01

    Proteasome activator PA28γ (REGγ, Ki antigen) has recently been demonstrated to display anti-apoptotic properties via enhancing Mdm2-p53 interaction, thereby facilitating ubiquitination and down-regulation of the tumor suppressor p53. In this study we demonstrate a correlation between cellular PA28γ levels and the sensitivity of cells towards apoptosis in different cellular contexts thereby confirming a role of proteasome activator PA28γ as an anti-apoptotic regulator. We investigated the anti-apoptotic role of PA28γ upon UV-C stimulation in B8 mouse fibroblasts stably overexpressing the PA28γ-encoding PSME3 gene and upon butyrate-induced apoptosis in human HT29 adenocarcinoma cells with silenced PSME3 gene. Interestingly, our results demonstrate that PA28γ has a strong influence on different apoptotic hallmarks, especially p53 phosphorylation and caspase activation. In detail, PA28γ and effector caspases mutually restrict each other. PA28γ is a caspase substrate, if PA28γ levels are low. In contrast, PA28γ overexpression reduces caspase activities, including the caspase-dependent processing of PA28γ. Furthermore, overexpression of PA28γ resulted in a nuclear accumulation of transcriptional active p53. In summary, our findings indicate that even in a p53-dominated cellular context, pro-apoptotic signaling might be overcome by PA28γ-mediated caspase inhibition. PMID:26201457

  3. Conformational space and photochemistry of alpha-terpinene.

    PubMed

    Marzec, K M; Reva, I; Fausto, R; Malek, K; Proniewicz, L M

    2010-05-01

    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.

  4. 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.

  5. 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

  6. Efficient bioconversion of rice straw to ethanol with TiO2/UV pretreatment.

    PubMed

    Kang, Hee-Kyoung; Kim, Doman

    2012-01-01

    Rice straw is a lignocellulosic biomass that constitutes a renewable organic substance and alternative source of energy; however, its structure confounds the liberation of monosaccharides. Pretreating rice straw using a TiO(2)/UV system facilitated its hydrolysis with Accellerase 1000(™), suggesting that hydroxyl radicals (OH·) from the TiO(2)/UV system could degrade lignin and carbohydrates. TiO(2)/UV pretreatment was an essential step for conversion of hemicellulose to xylose; optimal conditions for this conversion were a TiO(2) concentration of 0.1% (w/v) and an irradiation time of 2 h with a UV-C lamp at 254 nm. After enzymatic hydrolysis, the sugar yields from rice straw pretreated with these parameters were 59.8 ± 0.7% of the theoretical for glucose (339 ± 13 mg/g rice straw) and 50.3 ± 2.8% for xylose (64 ± 3 mg/g rice straw). The fermentation of enzymatic hydrolysates containing 10.5 g glucose/L and 3.2 g xylose/L with Pichia stipitis produced 3.9 g ethanol/L with a corresponding yield of 0.39 g/g rice straw. The maximum possible ethanol conversion rate is 76.47%. TiO(2)/UV pretreatment can be performed at room temperature and atmospheric pressure and demonstrates potential in large-scale production of fermentable sugars. PMID:21909680

  7. Regulatory interplay of Cockayne syndrome B ATPase and stress-response gene ATF3 following genotoxic stress.

    PubMed

    Kristensen, Ulrik; Epanchintsev, Alexey; Rauschendorf, Marc-Alexander; Laugel, Vincent; Stevnsner, Tinna; Bohr, Vilhelm A; Coin, Frédéric; Egly, Jean-Marc

    2013-06-18

    Cockayne syndrome type B ATPase (CSB) belongs to the SwItch/Sucrose nonfermentable family. Its mutations are linked to Cockayne syndrome phenotypes and classically are thought to be caused by defects in transcription-coupled repair, a subtype of DNA repair. Here we show that after UV-C irradiation, immediate early genes such as activating transcription factor 3 (ATF3) are overexpressed. Although the ATF3 target genes, including dihydrofolate reductase (DHFR), were unable to recover RNA synthesis in CSB-deficient cells, transcription was restored rapidly in normal cells. There the synthesis of DHFR mRNA restarts on the arrival of RNA polymerase II and CSB and the subsequent release of ATF3 from its cAMP response element/ATF target site. In CSB-deficient cells ATF3 remains bound to the promoter, thereby preventing the arrival of polymerase II and the restart of transcription. Silencing of ATF3, as well as stable introduction of wild-type CSB, restores RNA synthesis in UV-irradiated CSB cells, suggesting that, in addition to its role in DNA repair, CSB activity likely is involved in the reversal of inhibitory properties on a gene-promoter region. We present strong experimental data supporting our view that the transcriptional defects observed in UV-irradiated CSB cells are largely the result of a permanent transcriptional repression of a certain set of genes in addition to some defect in DNA repair. PMID:23733932

  8. On C J and C T in conformal QED

    NASA Astrophysics Data System (ADS)

    Giombi, Simone; Tarnopolsky, Grigory; Klebanov, Igor R.

    2016-08-01

    QED with a large number N of massless fermionic degrees of freedom has a conformal phase in a range of space-time dimensions. We use a large N diagrammatic approach to calculate the leading corrections to C T , the coefficient of the two-point function of the stress-energy tensor, and C J , the coefficient of the two-point function of the global symmetry current. We present explicit formulae as a function of d and check them versus the expectations in 2 and 4 - ɛ dimensions. Using our results in higher even dimensions we find a concise formula for C T of the conformal Maxwell theory with higher derivative action {F}_{μ ν }{(-{nabla}^2)}^{d/2-2}{F}^{μ ν } . In d = 3, QED has a topological symmetry current, and we calculate the correction to its two-point function coefficient, C J top . We also show that some RG flows involving QED in d = 3 obey C T UV > C T IR and discuss possible implications of this inequality for the symmetry breaking at small values of N.

  9. 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.

  10. 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

  11. UV-resistant yeasts isolated from a high-altitude volcanic area on the Atacama Desert as eukaryotic models for astrobiology.

    PubMed

    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

    2015-08-01

    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. PMID:26147800

  12. "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. PMID:26982218

  13. UV-resistant yeasts isolated from a high-altitude volcanic area on the Atacama Desert as eukaryotic models for astrobiology.

    PubMed

    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

    2015-08-01

    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.

  14. Fluorescence decay of dyed protozoa: differences between stressed and non-stressed cysts.

    PubMed

    dos Santos, Samuel Ricardo; Branco, Nilson; Franco, Regina Maura Bueno; Paterniani, José Euclides Stipp; Katsumata, Masakazu; Barlow, Peter W; Gallep, Cristiano de Mello

    2015-11-01

    Several series of tests have shown that fresh, intact samples of Giardia duodenalis and Cryptosporidium parvum (oo)cysts are not marked by fluorescent probes such as carboxyfluorcein-succinimidyl-diacetate-ester (CFDA-SE), C12-resazurin and SYTOX® Green, probably because of their robust cell walls. These dyes fail to indicate the viability of such protozoa and allow negative responses to be recorded from living and infectious samples. Cryptosporidium parvum showed stronger isolation from chemicals, with living oocysts remaining unstained by the probe for up to 90 days after extraction. However, in further fluorescence decay (FD) experiments run with G. duodenalis samples stained using CFDA-SE (comprising living, non-stressed but aged cysts, heat-killed samples and UV-C-stressed samples) each showed a different FD decay profile, here studied in seven series of tests of five replicates each. The FD profiles were fitted by double-exponential decay kinetics, with the decay constant k2 being five times higher than k1. This FD procedure is fast and can be easily reproduced in 10 steps, taking ~ 1 h of laboratory work for already purified samples.

  15. "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.

  16. Thermal and photo stability of phenolic constituents of an Achyrocline satureioides spray-dried powder.

    PubMed

    Holzschuh, M H; Silva, D M; Schapoval, E E S; Bassani, V L

    2007-12-01

    Thermal and the photo stabilities of an Achyrocline satureioides powder (SDP40) were evaluated in particular concerning the total polyphenol content as well as the main identified constituents quercetin, luteolin, 3-O-methylquercetin and caffeic acid. SDP40 presented good stability for nine months under normal storage conditions of 25 degrees C temperature and 60% relative humidity (RH). In accelerated term testing, 50 degrees C temperature and 90% RH and also in stress testing, 80 degrees C, caffeic acid and a non-identified constituent P3 were the most instable constituents. Luteolin and 3-O-methylquercetin were the most stable constituents. Quercetin presented an unusual behavior, improving its concentration after 1 month at 50 degrees C or 2 days at 80 degrees C exposition, followed by a decrease in its concentration. The hypothesis that this observation is related to the simultaneous decreasing of a non-identified peak P3 or to the hydrolysis of a non-identified precursor as a quercetin heteroside is being investigated. The SDP40 presented good stability against UV-C light when conditioned in amber or transparent containers, but it suffered degradation when stored in open-dishes. In summary, the total polyphenol content remains within acceptable limits of 10% under normal storage conditions for nine months. However, the LC polyphenol analysis demonstrated that the behavior of individual constituents has still to be enlightened.

  17. 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.

  18. 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.

  19. 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.

  20. Annual solar UV exposure and biological effective dose rates on the Martian surface

    NASA Astrophysics Data System (ADS)

    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.

  1. Competitive removal of pharmaceuticals from environmental waters by adsorption and photocatalytic degradation.

    PubMed

    Rioja, N; Benguria, P; Peñas, F J; Zorita, S

    2014-10-01

    This work explores the competitive removal of pharmaceuticals from synthetic and environmental waters by combined adsorption-photolysis treatment. Five drugs usually present in waterways have been used as target compounds, some are pseudo-persistent pollutants (carbamazepine, clofibric acid, and sulfamethoxazole) and others are largely consumed (diclofenac and ibuprofen). The effect of the light source on adsorption of drugs onto activated carbons followed by photolysis with TiO2 was assessed, being UV-C light the most effective for drug removal in both deionized water and river water. Different composites prepared from titania nanoparticles and powdered activated carbons were tested in several combined adsorption-photocatalysis assays. The composites prepared by calcination at 400 °C exhibited much better performance than those synthesized at 500 °C, being the C400 composite the most effective one. Furthermore, some synthetic waters containing dissolved species and environmental waters were used to investigate the effect of the aqueous matrix on each drug removal. In general, photocatalyst deactivation was found in synthetic and environmental waters. This was particularly evident in the experiments performed with bicarbonate ions as well as with wastewater effluent. In contrast, tests conducted in seawater showed adsorption and photocatalytic degradation yields comparable to those obtained in deionized water. Considering the peculiarities of substrate competition in each aqueous matrix, the combined adsorption-photolysis treatment generally increased the overall elimination of drugs in water. PMID:24532206

  2. 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%.

  3. Improvement of Biological Indicators by Uniformly Distributing Bacillus subtilis Spores in Monolayers To Evaluate Enhanced Spore Decontamination Technologies.

    PubMed

    Raguse, Marina; Fiebrandt, Marcel; Stapelmann, Katharina; Madela, Kazimierz; Laue, Michael; Lackmann, Jan-Wilm; Thwaite, Joanne E; Setlow, Peter; Awakowicz, Peter; Moeller, Ralf

    2016-04-01

    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 × 10(7) 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

  4. Design and demonstration of ultra-wide bandgap AlGaN tunnel junctions

    NASA Astrophysics Data System (ADS)

    Zhang, Yuewei; Krishnamoorthy, Sriram; Akyol, Fatih; Allerman, Andrew A.; Moseley, Michael W.; Armstrong, Andrew M.; Rajan, Siddharth

    2016-09-01

    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. 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.

  5. Competitive removal of pharmaceuticals from environmental waters by adsorption and photocatalytic degradation.

    PubMed

    Rioja, N; Benguria, P; Peñas, F J; Zorita, S

    2014-10-01

    This work explores the competitive removal of pharmaceuticals from synthetic and environmental waters by combined adsorption-photolysis treatment. Five drugs usually present in waterways have been used as target compounds, some are pseudo-persistent pollutants (carbamazepine, clofibric acid, and sulfamethoxazole) and others are largely consumed (diclofenac and ibuprofen). The effect of the light source on adsorption of drugs onto activated carbons followed by photolysis with TiO2 was assessed, being UV-C light the most effective for drug removal in both deionized water and river water. Different composites prepared from titania nanoparticles and powdered activated carbons were tested in several combined adsorption-photocatalysis assays. The composites prepared by calcination at 400 °C exhibited much better performance than those synthesized at 500 °C, being the C400 composite the most effective one. Furthermore, some synthetic waters containing dissolved species and environmental waters were used to investigate the effect of the aqueous matrix on each drug removal. In general, photocatalyst deactivation was found in synthetic and environmental waters. This was particularly evident in the experiments performed with bicarbonate ions as well as with wastewater effluent. In contrast, tests conducted in seawater showed adsorption and photocatalytic degradation yields comparable to those obtained in deionized water. Considering the peculiarities of substrate competition in each aqueous matrix, the combined adsorption-photolysis treatment generally increased the overall elimination of drugs in water.

  6. 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.

  7. 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.

  8. Efficacy of three light technologies for reducing microbial populations in liquid suspensions.

    PubMed

    Birmpa, Angeliki; Vantarakis, Apostolos; Paparrodopoulos, Spyros; Whyte, Paul; Lyng, James

    2014-01-01

    The aim of the current study was to evaluate the effectiveness of three nonthermal light technologies (NUV-Vis, continuous UV, and HILP) on their ability to inactivate Escherichia coli K12 and Listeria innocua.  E. coli K12 was selected as a representative microorganism for the enterohaemorrhagic foodborne pathogen E. coli O157:H7 and L. innocua as a surrogate microorganism for the common foodborne pathogen Listeria monocytogenes, respectively. The liquid matrix used for the disinfection experiments was a liquid matrix (MRD solution). The results of the present study show that the HILP treatment inactivated both E. coli and L. innocua more rapidly and effectively than either continuous UV-C or NUV-vis treatment. With HILP at 2.5 cm from the lamp, E. coli and L. innocua populations were reduced by 3.07 and 3.77 log10 CFU/mL, respectively, after a 5 sec treatment time, and were shown to be below the limit of detection (<0.22 log10 CFU/mL) following 30 sec exposure to HILP (106.2 J/cm(2)). These studies demonstrate the bactericidal efficacy of alternative nonthermal light technologies and their potential as decontamination strategies in the food industry.

  9. 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.

  10. 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.

  11. 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.

  12. “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

  13. Enhanced xylose fermentation and hydrolysate inhibitor tolerance of Scheffersomyces shehatae for efficient ethanol production from non-detoxified lignocellulosic hydrolysate.

    PubMed

    Senatham, Srisuda; Chamduang, Thada; Kaewchingduang, Yotin; Thammasittirong, Anon; Srisodsuk, Malee; Elliston, Adam; Roberts, Ian N; Waldron, Keith W; Thammasittirong, Sutticha Na-Ranong

    2016-01-01

    Effective conversion of xylose into ethanol is important for lignocellulosic ethanol production. In the present study, UV-C mutagenesis was used to improve the efficiency of xylose fermentation. The mutated Scheffersomyces shehatae strain TTC79 fermented glucose as efficiently and xylose more efficiently, producing a higher ethanol concentration than the wild-type. A maximum ethanol concentration of 29.04 g/L was produced from 71.31 g/L xylose, which was 58.95 % higher than that of the wild-type. This mutant also displayed significantly improved hydrolysate inhibitors tolerance and increased ethanol production from non-detoxified lignocellulosic hydrolysates. The ethanol yield, productivity and theoretical yield by TTC79 from sugarcane bagasse hydrolysate were 0.46 g/g, 0.20 g/L/h and 90.61 %, respectively, while the corresponding values for the wild-type were 0.20 g/g, 0.04 g/L/h and 39.20 %, respectively. These results demonstrate that S. shehatae TTC79 is a useful non-recombinant strain, combining efficient xylose consumption and high inhibitor tolerance, with potential for application in ethanol production from lignocellulose hydrolysates. PMID:27462488

  14. The removal of UV-induced pyrimidine dimers from DNA of rat skin cells in vitro and in vivo in relation to aging.

    PubMed

    Mullaart, E; Roza, L; Lohman, P H; Vijg, J

    1989-03-01

    Young and old rats were compared with respect to the capacity of their skin fibroblasts and epidermal keratinocytes to remove low levels of ultraviolet light (UV) induced UV-endonuclease sensitive sites (pyrimidime dimers) from their DNA, in vitro and in vivo, respectively. In vitro, over a 24-h time period, fibroblasts from both young and old rats were found to remove about 20% of the pyrimidine dimers originally induced by 4.6 J/m2 of UV-C. In vivo, after 2.6 kJ/m2 of UV-B hardly any UV lesions were found to be present in fibroblasts, as demonstrated by immunohistochemistry using an anti-thymine dimer antibody. As reported earlier (Mullaart et al., J. Invest. Dermatol., 90 (1988) 346-349) cultured epidermal keratinocytes do not differ from cultured fibroblasts in UV repair kinetics, whereas in vivo they remove at least 50% of the pyrimidine dimers induced by 4 kJ/m2 of UV-B within 3 h. We now show that epidermal keratinocytes from old rats are not deficient in their in vivo repair characteristics upon this low UV-B dose. However, since a considerable fraction of the pyrimidine dimers appeared to be persistent in fibroblasts and keratinocytes, demonstrated by both enzymatic and immunochemical assays, the possibility is discussed that long-term exposure of skin cells to UV may lead to an accumulation of DNA damage with age.

  15. Controlled mechanical fracture for fabricating microchannels with various size gradients.

    PubMed

    Kim, Hong-Nam; Lee, Sung-Hoon; Suh, Kahp-Yang

    2011-02-21

    We present a simple method to generate cracks with controllable size (depth and width) and space gradients using deep surface oxidation and anisotropic mechanical stretching. To generate a thick oxidation layer (<∼7 µm), a polydimethylsiloxane (PDMS) slab of uniform or varying thickness was exposed to UV/ozone for less than 30 min in the UV-C wavelength including wavelengths of 185 and 254 nm. Subsequently, the PDMS slab was wrapped on a cylindrical support (radius: 11 mm) to apply a uniform bending strain (<21%), resulting in equally separated, anisotropic cracks over a large area. By modulating initial oxidation depth and applied bending stress, cracks of varying sizes and spaces were formed on a single PDMS slab. Furthermore, multiple, sequential cracks were generated by increasing the strain in a step-wise fashion and multi-directional cracks by applying the strain with an orientation angle. Finally, size and space-varying cracks were formed between two adjacent large channels in an interconnected format by selective masking and irreversible bonding.

  16. 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

  17. Protection of enzymes from photodegradation by entrapment within alumina.

    PubMed

    Shapovalova, Olga E; Levy, David; Avnir, David; Vinogradov, Vladimir V

    2016-10-01

    Most enzymes are highly sensitive to UV-light in all of its ranges and their activity can irreversibly drop even after a short time of exposure. Here we report a solution of this problem by using sol-gel matrices as effective protectors against this route of enzyme inactivation and denaturation. The concept presented here utilizes several modes of action: First, the entrapment within the rigid ceramic sol-gel matrix, inhibits denaturation motions, and the hydration shell around the entrapped protein provides extra protection. Second, the matrix itself - alumina in this report - absorbs UV light. And third, sol-gel materials have been shown to be quite universal in their ability to entrap small molecules, and so co-entrapment with well documented sun-screening molecules (2-hydroxybenzophenone, 2,2'-dihydroxybenzophenone, and 2,2'-dihydroxy-4-methoxybenzophenone) is an additional key protective tool. Three different enzymes as models were chosen for the experiments: carbonic anhydrase, acid phosphatase and horseradish peroxidase. All showed greatly enhanced UV (regions UV-A, UV-B, and UV-C) stabilization after entrapment within the doped sol-gel alumina matrices.

  18. Low-Pressure UV Inactivation and DNA Repair Potential of Cryptosporidium parvum Oocysts

    PubMed Central

    Shin, Gwy-Am; Linden, Karl G.; Arrowood, Michael J.; Sobsey, Mark D.

    2001-01-01

    Because Cryptosporidium parvum oocysts are very resistant to conventional water treatment processes, including chemical disinfection, we determined the kinetics and extent of their inactivation by monochromatic, low-pressure (LP), mercury vapor lamp UV radiation and their subsequent potential for DNA repair of UV damage. A UV collimated-beam apparatus was used to expose suspensions of purified C. parvum oocysts in phosphate-buffered saline, pH 7.3, at 25°C to various doses of monochromatic LP UV. C. parvum infectivity reductions were rapid, approximately first order, and at a dose of 3 mJ/cm2 (=30 J/m2), the reduction reached the cell culture assay detection limit of ∼3 log10. At UV doses of 1.2 and 3 mJ/cm2, the log10 reductions of C. parvum oocyst infectivity were not significantly different for control oocysts and those exposed to dark or light repair conditions for UV-induced DNA damage. These results indicate that C. parvum oocysts are very sensitive to inactivation by low doses of monochromatic LP UV radiation and that there is no phenotypic evidence of either light or dark repair of UV-induced DNA damage. PMID:11425717

  19. 2-Aminopurine hairpin probes for the detection of ultraviolet-induced DNA damage.

    PubMed

    El-Yazbi, Amira F; Loppnow, Glen R

    2012-05-13

    Nucleic acid exposure to radiation and chemical insults leads to damage and disease. Thus, detection and understanding DNA damage is important for elucidating molecular mechanisms of disease. However, current methods of DNA damage detection are either time-consuming, destroy the sample, or are too specific to be used for generic detection of damage. In this paper, we develop a fluorescence sensor of 2-aminopurine (2AP), a fluorescent analogue of adenine, incorporated in the loop of a hairpin probe for the quantification of ultraviolet (UV) C-induced nucleic acid damage. Our results show that the selectivity of the 2AP hairpin probe to UV-induced nucleic acid damage is comparable to molecular beacon (MB) probes of DNA damage. The calibration curve for the 2AP hairpin probe shows good linearity (R(2)=0.98) with a limit of detection of 17.2 nM. This probe is a simple, fast and economic fluorescence sensor for the quantification of UV-induced damage in DNA.

  20. Efficacy of Three Light Technologies for Reducing Microbial Populations in Liquid Suspensions

    PubMed Central

    Paparrodopoulos, Spyros; Whyte, Paul

    2014-01-01

    The aim of the current study was to evaluate the effectiveness of three nonthermal light technologies (NUV-Vis, continuous UV, and HILP) on their ability to inactivate Escherichia coli K12 and Listeria innocua.  E. coli K12 was selected as a representative microorganism for the enterohaemorrhagic foodborne pathogen E. coli O157:H7 and L. innocua as a surrogate microorganism for the common foodborne pathogen Listeria monocytogenes, respectively. The liquid matrix used for the disinfection experiments was a liquid matrix (MRD solution). The results of the present study show that the HILP treatment inactivated both E. coli and L. innocua more rapidly and effectively than either continuous UV-C or NUV-vis treatment. With HILP at 2.5 cm from the lamp, E. coli and L. innocua populations were reduced by 3.07 and 3.77 log10 CFU/mL, respectively, after a 5 sec treatment time, and were shown to be below the limit of detection (<0.22 log10 CFU/mL) following 30 sec exposure to HILP (106.2 J/cm2). These studies demonstrate the bactericidal efficacy of alternative nonthermal light technologies and their potential as decontamination strategies in the food industry. PMID:24724092

  1. 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

  2. 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

  3. Exposure of mice to cigarette smoke and/or light causes DNA alterations in heart and aorta.

    PubMed

    Izzotti, Alberto; D'Agostini, Francesco; Balansky, Roumen; Degan, Paolo; Pennisi, Tanya M; Steele, Vernon E; De Flora, Silvio

    2008-09-26

    Cigarette smoke (CS) is a major risk factor for cardiovascular diseases, cancer, and other chronic degenerative diseases. UV-containing light is the most ubiquitous DNA-damaging agent existing in nature, but its possible role in cardiovascular diseases had never been suspected before, although it is known that mortality for cardiovascular diseases is increased during periods with high temperature and solar irradiation. We evaluated whether exposure of Swiss CD-1 mice to environmental CS (ECS) and UV-C-covered halogen quartz lamps, either individually or in combination, can cause DNA damage in heart and aorta cells. Nucleotide alterations were evaluated by (32)P postlabeling methods and by HPLC-electrochemical detection. The whole-body exposure of mice to ECS considerably increased the levels of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) and of bulky DNA adducts in both heart and aorta. Surprisingly, even exposure to a light that simulated solar irradiation induced oxidatively generated damage in both tissues. The genotoxic effects of UV light in internal organs is tentatively amenable to formation of unidentified long-lived mutagenic products in the skin of irradiated mice. Nucleotide alterations were even more pronounced when the mice were exposed to smoke and/or light during the first 5 weeks of life rather than during adulthood for an equivalent period of time. Although the pathogenetic meaning is uncertain, DNA damage in heart and aorta may tentatively be related to cardiomyopathies and to the atherogenesis process, respectively.

  4. IUE Observations of the Trifid and Logoon H II Regions

    NASA Astrophysics Data System (ADS)

    Dufour, Reginald J.

    We request IUE observing time to obtain low dispersion SWP and LWP spectra of several positions in the Sagittarius Arm H II regions M20 (The Trifid Nebula) and M8 (The Lagoon Nebula). The short term objective is to measure the strengths of certain UV emission lines useful for the determination of the carbon, nitrogen, silicon, and magnesium gaseous-phase abundances in these nebulae. Success would increase three-fold the number of galactic H II regions for which the carbon abundance has been determined from the UV C III] and C II] lines (only the Orion Nebula has been successfully studied to date). Our larger and longer term objective is to combine the IUE observations with ground -based spectroscopy and imagery, and possibly with radio and IRAS observations as well, in order to study spatial variations in ionization structure, temperature, density, and dust distribution, as well as to compare the empirical data with recently developed H II region models. The Trifid Nebula is particularly suited for such study and comparison since it shows a very symmetric ionization structure.

  5. 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.

  6. 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

    2016-06-01

    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.

  7. 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. PMID:26370303

  8. 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

  9. 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

  10. 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

  11. 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.

  12. 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

  13. Effect of Solar UV-B Radiation on a Phyllosphere Bacterial Community

    PubMed Central

    Jacobs, Janette L.; Sundin, George W.

    2001-01-01

    The effect of solar UV-B radiation on the population dynamics and composition of the culturable bacterial community from peanut (Arachis hypogeae L.) was examined in field studies using plants grown under UV-B−transmitting (UV-B+) or UV-B−excluding (UV-B−) plastic filters. Our data demonstrate that solar UV-B selection alters phyllosphere bacterial community composition and that UV tolerance is a prevalent phenotype late in the season. The total bacterial population size was not affected by either UV-B treatment. However, isolates from the UV-B+ plots (n = 368) were significantly more UV tolerant than those from the UV-B− (n = 363) plots. UV sensitivity was determined as the minimal inhibitory dose of UV that resulted in an inhibition of growth compared to the growth of a nonirradiated control. The difference in minimal inhibitory doses among bacterial isolates from UV-B+ and UV-B− treatments was mainly partitioned among nonpigmented isolates, with pigmented isolates as a group being characterized as UV tolerant. A large increase in UV tolerance was observed within isolate groups collected late (89 and 96 days after planting) in the season. Identification of 200 late-season isolates indicated that the predominant UV-tolerant members of this group were Bacillus coagulans, Clavibacter michiganensis, and Curtobacterium flaccumfaciens. We selected C. michiganensis as a model UV-tolerant epiphyte to study if cell survival on UV-irradiated peanut leaves was increased relative to UV survival in vitro. The results showed an enhancement in the survival of C. michiganensis G7.1, especially following high UV-C doses (300 and 375 J m−2), that was evident between 24 and 96 h after inoculation. A dramatic increase in the in planta/in vitro survival ratio was observed over the entire 96-h experiment period for C. michiganensis T5.1. PMID:11722897

  14. 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.

  15. 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

  16. New HST Observations of the Wolf-Rayet Nebula NGC 6888

    NASA Astrophysics Data System (ADS)

    Dufour, R. J.; Moore, B. D.; Hester, J. J.; Scowen, P. A.; Buckalew, B. A.

    2002-05-01

    HST/WFPC2 imagery and STIS spectra of the circumstellar shell NGC 6888 are presented. The nebula was formed by the collision of the stellar wind of the WN6 star HD 192163 with material shed during its preceding red supergiant phase. The resulting nebula is an 8 pc x 5 pc photoionized shell enveloped in a shock-heated skin of emission powered by the internal pressure of the wind-blown bubble. We present color-coded pictures of our new WFPC2 imagery along the shell's northern perimeter. These included three fields imaged using the F502N, F656N, and F658N filters, and a previously studied region using F487N and F658N. STIS spectra covering the ~1650-9500 Å wavelength range of four knots and surrounding medium were obtained for comprehensive studies of spatial variations in various emission lines. Collectively the new data permit a global view of the shell material at different times relative to the breakout of the hot bubble interior. The NE pointing was observed previously with WFPC2, and analyzed by comparison with photoionization models. The earlier work, presented in Moore, Hester and Scowen 2000 (MHS00) relied on ground-based observations. Our new observations show that previous estimates of [N II]/Hα were low by 20-50%. The lower gas density in the new models is in better agreement with the evolutionary scenario discussed in MHS00. The new ionizing flux is closer to that of the stellar model of Crowther & Smith 1996. The absence of the UV C II] & C III] lines in our STIS spectra allows only an upper limit on the carbon abundance in the nebula. Support for the observations came from AURA/STScI to Rice & ASU as General Observer Program GO-08568.

  17. Dose-response of chronic ultraviolet exposure on epidermal forward scattering-absorption in SK-1 hairless mouse skin.

    PubMed

    Menter, J M; Agin, P P; Sayre, R M; Willis, I

    1992-05-01

    This work provides a dose-response model of UV-induced epidermal-stratum corneum thickening induced by irradiation at wavelength lambda. This model assumes that photobiochemical reaction(s) can give rise to hyperplasia in a manner which is predictable from a simple photochemical kinetic scheme. In this work, we derive an equation which predicts an approximately linear relationship between the logarithm of the increase in optical skin thickening measured at 320 nm (delta OD320) and total cumulative dose (DT) seen by the target cells in or near the basal layer. For each excitation wavelength lambda, the slope R(lambda) of the log delta OD320 vs DT plot is proportional to epsilon(lambda) phi rx, where epsilon(lambda) is the extinction coefficient for the target chromophore at excitation wavelength, and phi rx is the quantum yield for the photochemical reaction(s) leading to hyperplasia. Our data previously obtained from irradiation of SK-1 hairless mice with "monochromatic" UV wavebands at 280, 290, 300, 307 and 313 nm (Menter et al., 1988, Photochem. Photobiol. 47, 225-260.) and data from Sterenborg and van der Leun at 254 and 313 nm (1988, Photodermatology 5, 71-82) are in good agreement with this model, except for 254 and 280 nm excitation, which are greatly attenuated by epidermis-stratum corneum. For excitation at the latter wavelengths, "dark" regressive processes successfully compete with the "light" reaction(s) which lead to (pre)cancerous lesion. This difficulty notwithstanding, the "intrinsic" action spectrum for hyperplasia derived from these measurements indicates that the target chromophore preferentially absorbs in the UV-C region.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. The UV-VIS spectrometer for the ExoMars mission

    NASA Astrophysics Data System (ADS)

    Patel, M. R.; Zarnecki, J. C.; Leese, M. R.; Towner, M. C.; Muller, C.; Depiesse, C.; Moreau, D.; Gillotay, D.; Chakrabarti, S.

    The ExoMars scientific payload is optimised to search for biomarkers and potential astrobiological habitats in the Martian near-surface environment The UV-VIS spectrometer UVIS is designed to determine for the first time the magnitude of the UV flux reaching the Mars surface in the ranges of UV-C 190-280nm and UV-B 280-315nm that in general have a deleterious impact on most carbon-based organic structures Also intense short wavelength UV can lead to the production of oxidizing radicals that could affect the potential for extant life to persist Great uncertainty lies in the derivation of optical properties of suspended dust in the martian atmosphere for UV wavelengths - little agreement has been reached to date due to the lack of detailed spectroscopic investigation and these parameters are required for accurate modelling of the transfer of UV to the surface in astrobiological investigations This instrument will provide surface spectra ranging from the UV to visible thus allowing the derivation of optical properties across a wide region of wavelength and simultaneous cross-comparison with many previous observations in the visible region of the spectrum UVIS is an extremely compact spectrometer and is currently in development through ESA to miniaturise and raise technology development in time for the ExoMars mission UVIS will monitor the local solar irradiance at the Mars surface at high resolution 1-2 nm throughout the UV and visible spectrum 200-650 nm with a mass requirement of 300g The spectrometer utilises a 1024 element linear photodiode array

  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 Total Ozone Series of Arosa: History, Homogenization and new results using statistical extreme value theory

    NASA Astrophysics Data System (ADS)

    Staehelin, J.; Rieder, H. E.; Maeder, J. A.; Ribatet, M.; Davison, A. C.; Stübi, R.

    2009-04-01

    Atmospheric ozone protects the biota living at the Earth's surface from harmful solar UV-B and UV-C radiation. The global ozone shield is expected to gradually recover from the anthropogenic disturbance of ozone depleting substances (ODS) in the coming decades. The stratospheric ozone layer at extratropics might significantly increase above the thickness of the chemically undisturbed atmosphere which might enhance ozone concentrations at the tropopause altitude where ozone is an important greenhouse gas. At Arosa, a resort village in the Swiss Alps, total ozone measurements started in 1926 leading to the longest total ozone series of the world. One Fery spectrograph and seven Dobson spectrophotometers were operated at Arosa and the method used to homogenize the series will be presented. Due to its unique length the series allows studying total ozone in the chemically undisturbed as well as in the ODS loaded stratosphere. The series is particularly valuable to study natural variability in the period prior to 1970, when ODS started to affect stratospheric ozone. Concepts developed by extreme value statistics allow objective definitions of "ozone extreme high" and "ozone extreme low" values by fitting the (daily mean) time series using the Generalized Pareto Distribution (GPD). Extreme high ozone events can be attributed to effects of ElNino and/or NAO, whereas in the chemically disturbed stratosphere high frequencies of extreme low total ozone values simultaneously occur with periods of strong polar ozone depletion (identified by statistical modeling with Equivalent Stratospheric Chlorine times Volume of Stratospheric Polar Clouds) and volcanic eruptions (such as El Chichon and Pinatubo).

  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. PMID:26272089

  2. 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

  3. 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.

  4. 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. PMID:26010807

  5. UV radiation induces delayed hyperrecombination associated with hypermutation in human cells.

    PubMed

    Durant, Stephen T; Paffett, Kimberly S; Shrivastav, Meena; Timmins, Graham S; Morgan, William F; Nickoloff, Jac A

    2006-08-01

    Ionizing radiation induces delayed genomic instability in human cells, including chromosomal abnormalities and hyperrecombination. Here, we investigate delayed genome instability of cells exposed to UV radiation. We examined homologous recombination-mediated reactivation of a green fluorescent protein (GFP) gene in p53-proficient human cells. We observed an approximately 5-fold enhancement of delayed hyperrecombination (DHR) among cells surviving a low dose of UV-C (5 J/m2), revealed as mixed GFP+/- colonies. UV-B did not induce DHR at an equitoxic (75 J/m2) dose or a higher dose (150 J/m2). UV is known to induce delayed hypermutation associated with increased oxidative stress. We found that hypoxanthine phosphoribosyltransferase (HPRT) mutation frequencies were approximately 5-fold higher in strains derived from GFP+/- (DHR) colonies than in strains in which recombination was directly induced by UV (GFP+ colonies). To determine whether hypermutation was directly caused by hyperrecombination, we analyzed hprt mutation spectra. Large-scale alterations reflecting large deletions and insertions were observed in 25% of GFP+ strains, and most mutants had a single change in HPRT. In striking contrast, all mutations arising in the hypermutable GFP+/- strains were small (1- to 2-base) changes, including substitutions, deletions, and insertions (reminiscent of mutagenesis from oxidative damage), and the majority were compound, with an average of four hprt mutations per mutant. The absence of large hprt deletions in DHR strains indicates that DHR does not cause hypermutation. We propose that UV-induced DHR and hypermutation result from a common source, namely, increased oxidative stress. These two forms of delayed genome instability may collaborate in skin cancer initiation and progression. PMID:16880516

  6. 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.

  7. 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.

  8. Constraining the N2O5 UV absorption cross-section from spectroscopic trace gas measurements in the tropical mid-stratosphere

    NASA Astrophysics Data System (ADS)

    Kritten, L.; Butz, A.; Chipperfield, M. P.; Dorf, M.; Dhomse, S.; Hossaini, R.; Oelhaf, H.; Prados-Roman, C.; Wetzel, G.; Pfeilsticker, K.

    2014-02-01

    The absorption cross-section of N2O5, σN2O5(λ, T), which is known from laboratory measurements with the uncertainty of a factor of 2 (Table 4-2 in JPL-2011, Sander et al., 2011), was investigated by balloon-borne observations of the relevant trace gases in the tropical mid-stratosphere. The method relies on the observation of the diurnal variation of NO2 supported by detailed photochemical modelling of NOy (NOx(= NO + NO2) + NO3 + 2N2O5 + ClONO2 + HO2NO2 +BrONO2 + HNO3) photochemistry. Simulations are initialised with O3 measured by direct sun observations, the NOy partitioning from MIPAS-B (Michelson Interferometer for Passive Atmospheric Sounding-Balloon) observations in similar air masses at nighttime, and all other relevant species from simulations of the SLIMCAT chemical transport model (CTM). Best agreement between the simulated and observed diurnal increase of NO2 is found if the σN2O5(λ, T) is scaled by a factor of 1.6 ± 0.8 in the UV-C (200-260 nm) and by a factor of 0.9 ± 0.26 in the UV-B/A (260-350 nm), compared to current recommendations. In consequence, at 30 km altitude, the N2O5 lifetime against photolysis becomes a factor of 0.77 shorter at solar zenith angle (SZA) of 30° than using the recommended σN2O5 (λ, T), and stays more or less constant at SZAs of 60°. Our scaled N2O5 photolysis frequency slightly reduces the lifetime (0.2-0.6%) of ozone in the tropical mid- and upper stratosphere, but not to an extent to be important for global ozone.

  9. Degradation characteristics of metoprolol during UV/chlorination reaction and a factorial design optimization.

    PubMed

    Nam, Seung-Woo; Yoon, Yeomin; Choi, Dae-Jin; Zoh, Kyung-Duk

    2015-03-21

    Metoprolol (MTP), a hypertension depressor, has been increasingly detected even after conventional water treatment processes. In this study, the removal of MTP was compared using chlorination (Cl2), UV-C photolysis, and UV/chlorination (Cl2/UV) reactions. The results showed that the UV/chlorination reaction was most effective for MTP removal. MTP removal during UV/chlorination reaction was optimized under various conditions of UV intensity (1.1-4.4 mW/cm(2)), chlorine dose (1-5 mg/L as Cl2), pH (2-9), and dissolved organic matter (DOM, 1-4 mgC/L) using a two-level factorial design with 16 experimental combinations of the four factors. Among the factors examined, DOM scavenging by OH radicals was the most dominant in terms of MTP removal during UV/chlorination reaction. The established model fit well with the experimental results using to various water samples including surface waters, filtered and tap water samples. The optimized conditions (UV intensity=4.4 mW/cm(2), [Cl2]=5 mg/L, pH 7, and [DOM]=0.8-1.1 mgC/L) of the model removed more than 78.9% of MTP for filtered water samples during UV/chlorination reaction. Using LC-MS/MS, five byproducts of MTP (molecular weight: 171, 211, 309, 313, and 341, respectively) were identified during UV/chlorination reaction. Based on this information, the MTP transformation mechanism during UV/chlorination was suggested. Our results imply that applying UV/chlorination process after filtration stage in the water treatment plant (WTP) would be the most appropriate for effective removal of MTP.

  10. Elimination by ozone of Shigella sonnei in shredded lettuce and water.

    PubMed

    Selma, María Victoria; Beltrán, David; Allende, Ana; Chacón-Vera, Eliseo; Gil, María Isabel

    2007-08-01

    Several outbreaks of shigellosis have been attributed to the consumption of contaminated fresh-cut vegetables. The minimal processing of these products make it difficult to ensure that fresh produce is safe for consumer. Chlorine-based agents have been often used to sanitize produce and reduce microbial populations in water applied during processing operations. However, the limited efficacy of chlorine-based agents and the production of chlorinated organic compounds with potential carcinogenic action have created the need to investigate the effectiveness of new decontamination techniques. In this study, the ability of ozone to inactivate S. sonnei inoculated on shredded lettuce and in water was evaluated. Furthermore, several disinfection kinetic models were considered to predict S. sonnei inactivation with ozone. Treatments with ozone (1.6 and 2.2 ppm) for 1 min decreased S. sonnei population in water by 3.7 and 5.6 log cfu mL(-1), respectively. Additionally, it was found that S. sonnei growth in nutrient broth was affected by ozone treatments. After 5.4 ppm ozone dose, lag-phases were longer for injured cells recovered at 10 degrees C than 37 degrees C. Furthermore, treated cells recovered in nutrient broth at 10 degrees C were unable to grow after 16.5 ppm ozone dose. Finally, after 5 min, S. sonnei counts were reduced by 0.9 and 1.4 log units in those shredded lettuce samples washed with 2 ppm of ozonated water with or without UV-C activation, respectively. In addition, S. sonnei counts were reduced by 1.8 log units in lettuce treated with 5 ppm for 5 min. Therefore, ozone can be an alternative treatment to chlorine for disinfection of wash water and for reduction of microbial population on fresh produce due to it decomposes to nontoxic products.

  11. 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. PMID:24277323

  12. 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.

  13. 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. PMID:27217356

  14. 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

  15. Sporulation Temperature Reveals a Requirement for CotE in the Assembly of both the Coat and Exosporium Layers of Bacillus cereus Spores.

    PubMed

    Bressuire-Isoard, Christelle; Bornard, Isabelle; Henriques, Adriano O; Carlin, Frédéric; Broussolle, Véronique

    2015-10-23

    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.

  16. 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

  17. In vivo evaluation of the penetration of topically applied drugs into human skin by spectroscopic methods.

    PubMed

    Sennhenn, B; Giese, K; Plamann, K; Harendt, N; Kölmel, K

    1993-01-01

    Spectroscopic techniques are reported on which allow to study in vivo the penetration behaviour of topically applied light-absorbing drugs into human skin. Remittance spectroscopy, a purely optical method, provides a good tool in both, skin adaptation by use of a remote viewing head coupled to the spectrometer via optical fibres, and adequate sensitivity for the detection of small amounts of the applied drugs. The measuring depth in the skin is determined by the wavelength-dependent optical penetration depth, which itself depends on light absorption and light scattering. In the UV-spectral region the optical penetration depth is of the order of the thickness of the stratum corneum (UV-A) or of only a superficial part of it (UV-B, UV-C). Fluorescence spectroscopy, another optical method, offers two kinds of drug detection, a direct one in case of self-fluorescent drugs or an indirect one being based on the light absorption of the drug, which may give rise to a screening of the self-fluorescence of the skin itself or of an applied marker. The measuring depth is comparable to that achieved with remittance spectroscopy. A third method is photothermal spectroscopy which is determined by thermal properties of the skin in addition to optical properties. Photothermal spectroscopy is unique in that it allows depth profiles of drug concentration to be measured non-invasively, as the photothermal measuring depth can be changed by varying the modulation frequency of the intensity-modulated incident light. Results of measurements demonstrating the potentials of these spectroscopic methods are presented.

  18. 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.

  19. Effects of microinjected photoreactivating enzyme on thymine dimer removal and DNA repair synthesis in normal human and xeroderma pigmentosum fibroblasts.

    PubMed

    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, e.g., (6-4) photoproducts, 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.

  20. Effect of spectral range in surface inactivation of Listeria innocua using broad-spectrum pulsed light.

    PubMed

    Woodling, Sarah E; Moraru, Carmen I

    2007-04-01

    Pulsed light (PL) treatment is an alternative to traditional thermal treatment that has the potential to achieve several log-cycle reductions in the concentration of microorganisms. One issue that is still debated is related to what specifically causes cell death after PL treatments. The main objective of this work was to elucidate which portions of the PL range are responsible for bacterial inactivation. Stainless steel coupons with controlled surface properties were inoculated with a known concentration of Listeria innocua in the stationary growth phase and treated with 1 to 12 pulses of light at a pulse rate of 3 pulses per s and a pulse width of 360 micros. The effects of the full spectrum (lambda = 180 to 1,100 nm) were compared with the effects obtained when only certain regions of UV, visible, and near-infrared light were used. The effectiveness of the treatments was determined in parallel by the standard plate count and most-probable-number techniques. At a fluence of about 6 J/cm(2), the full-spectrum PL treatment resulted in a 4.08-log reduction of L. innocua on a Mill finish surface, the removal of lambda < 200 nm diminished the reduction to only 1.64 log, and total elimination of UV light resulted in no lethal effects on L. innocua. Overwhelmingly, the portions of the PL spectrum responsible for bacterial death are the UV-B and UV-C spectral ranges (X < 300 nm), with some death taking place during exposure to UV-A radiation (300 < lambda < 400 nm) and no observable death upon exposure to visible and near-infrared light (lambda > 400 nm). This work provides additional supporting evidence that cell death in PL treatment is due to exposure to UV light. Additionally, it was shown that even a minor modification of the light path or the UV light spectrum in PL treatments can have a significant negative impact on the treatment intensity and effectiveness.

  1. Transcription coupled repair efficiency determines the cell cycle progression and apoptosis after UV exposure in hamster cells.

    PubMed

    Proietti De Santis, Luca; Garcia, Claudia Lorenti; Balajee, Adayabalam S; Latini, Paolo; Pichierri, Pietro; Nikaido, Osamu; Stefanini, Miria; Palitti, Fabrizio

    2002-03-28

    Nucleotide excision repair (NER) is a major pathway for the removal of bulky adducts and helix distorting lesions from the genomic DNA. NER is highly heterogeneous across the genome and operates principally at different levels of hierarchy. Transcription coupled repair (TCR), a special sub-pathway of NER and base excision repair (BER), is critical for cellular resistance after UV irradiation in mammalian cells. In this study, we have investigated the effects of UV-C irradiation on cell cycle progression and apoptosis in G1 synchronised isogenic hamster cell lines that are deficient in TCR and NER pathways. Our results revealed the existence of two apoptotic modes at low UV (2-4J/m2) doses in TCR deficient (UV61) and NER deficient (UV5) cells: one occurring in the first G1 and the other in the second G1-phase following the first division. At high UV doses (8-32J/m2), UV61 and UV5 cells underwent apoptosis without entry into S-phase after a permanent arrest in the initial G1. In contrast to repair deficient cells, parental TCR proficient AA8 cells did not show a significant G1 arrest and apoptosis at doses below 8J/m2. UV61 (proficient in repair of 6-4 photoproducts (PPs)) and UV5 (deficient in 6-4 PP repair) cells showed similar patterns of cell cycle progression and apoptosis. Taken together, these results suggest that the persistence of 6-4 PP and the replication inhibition may not be critical for apoptotic response in hamster cells. Instead, the extent of transcription blockage resulting from the TCR deficiency constitutes the major determining factor for G1 arrest and apoptosis.

  2. Transformation of avobenzone in conditions of aquatic chlorination and UV-irradiation.

    PubMed

    Trebše, Polonca; Polyakova, Olga V; Baranova, Maria; Kralj, Mojca Bavcon; Dolenc, Darko; Sarakha, Mohamed; Kutin, Alexander; Lebedev, Albert T

    2016-09-15

    Emerging contaminants represent a wide group of the most different compounds. They appear in the environment at trace levels due to human activity. Most of these compounds are not yet regulated. Sunscreen UV-filters play an important role among these emerging contaminants. In the present research the reactions of 4-tert-butyl-4'-methoxydibenzoylmethane (avobenzone), the most common UV filter in the formulation of sunscreens, were studied under the combined influence of active chlorine and UV-irradiation. Twenty five compounds were identified by GC/MS as transformation products of avobenzone in reactions of aquatic UV-irradiation and chlorination with sodium hypochlorite. A complete scheme of transformation of avobenzone covering all the semivolatile products is proposed. The identification of the two primary chlorination products (2-chloro-1-(4-tert-butylphenyl)-3-(4-methoxyphenyl)-1,3-propanedione and 2,2-dichloro-1-(4-tert-butylphenyl)-3-(4-methoxyphenyl)-1,3-propanedione) was confirmed by their synthesis and GC/MS and NMR analysis. Although the toxicities of the majority of these products remain unknown substituted chlorinated phenols and acetophenones are known to be rather toxic. Combined action of active chlorine and UV-irradiation results in the formation of some products (chloroanhydrides, chlorophenols) not forming in conditions of separate application of these disinfection methods. Therefore caring for people «well-being» it is of great importance to apply the most appropriate disinfection method. Since the primary transformation products partially resist powerful UV-C irradiation they may be treated as stable and persistent pollutants. PMID:27258620

  3. 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.

  4. Allometric analysis of the induced flavonols on the leaf surface of wild tobacco (Nicotiana attenuata).

    PubMed

    Roda, Amy L; Oldham, Neil J; Svatos, Ales; Baldwin, Ian T

    2003-02-01

    Trichomes excrete secondary metabolites that may alter the chemical composition of the leaf surface, reducing damage caused by herbivores, pathogens and abiotic stresses. We examined the surface exudates produced by Nicotiana attenuata Torr. Ex Wats., a plant known to contain and secrete a number of secondary metabolites that are toxic or a deterrent to herbivorous insects. Extractions specific to the leaf surface, the trichomes, and the laminar components demonstrated the localization of particular compounds. Diterpene glycosides occurred exclusively in leaf mesophyll, whereas nicotine was found in both the trichomes and mesophyll. Neither rutin nor nicotine was found on the leaf surface. Quercetin and 7 methylated derivatives were found in the glandular trichomes and appeared to be excreted onto the leaf surface. We examined the elicitation of these flavonols on the leaf surface with a surface-area allometric analysis, which measures changes in metabolites independent of the effects of leaf expansion. The flavonols responded differently to wounding, methyl jasmonate (MeJA), herbivore attack and UV-C radiation, and the response patterns corresponded to their compound-specific allometries. Finding greater amounts of quercetin on younger leaves and reduced amounts after herbivore feeding and MeJA treatment, we hypothesized that quercetin may function as an attractant, helping the insects locate a preferred feeding site. Consistent with this hypothesis, mirids (Tupiocoris notatus) were found more often on mature leaves sprayed with quercetin at a concentration typical of young leaves than on unsupplemented mature leaves. The composition of metabolites on the leaf surface of N. attenuata changes throughout leaf development and in response to herbivore attack or environmental stress, and these changes are mediated in part by responses of the glandular trichomes.

  5. Leptospira interrogans serovar Copenhageni Harbors Two lexA Genes Involved in SOS Response

    PubMed Central

    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 TTGTAN 10TACAA, 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. PMID:24098496

  6. 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.

  7. 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

  8. 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

  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. Antigenotoxic and antimutagenic effects of diphenyl ditelluride against several known mutagens in Chinese hamster lung fibroblasts.

    PubMed

    Trindade, Cristiano; Juchem, André L M; de Albuquerque, Nathália R M; de Oliveira, Iuri M; Rosa, Renato M; Guecheva, Temenouga N; Saffi, Jenifer; Henriques, João A P

    2015-11-01

    The present study evaluates antigenotoxic and antimutagenic properties of diphenyl ditelluride (DPDT) against several known mutagens in Chinese hamster lung fibroblasts (V79 cells). DPDT was not cytotoxic and genotoxic at concentrations ranging from 0.01 to 0.1 μM. The pre-treatment for 2h with this organotellurium compound at non-cytotoxic dose range (0.01, 0.05 and 0.1 μM) increased cell survival after challenge with hydrogen peroxide (H2O2), t-butyl hydroperoxide (t-BOOH), methylmethanesulphonate (MMS) or ultraviolet (UV)C radiation. In addition, the pre-treatment with DPDT decreased the DNA damage and Formamidopyrimidine DNA-glycosylase (Fpg)- and Endonuclease III (Endo III) sensitive sites induction by the studied genotoxic agents, as verified by comet assay and modified comet assay, respectively. The pre-treatment also reduced micronucleus frequency, revealing the protector effect of DPDT against MMS and UVC-induced mutagenesis. Our results demonstrate that DPDT-treated cells at concentration range of 0.01-0.1 μM do not change thiobarbituric acid reactive species (TBARS) levels and ROS generation. Moreover, DPDT pre-treatment at this concentration range decreases the ROS induction by H2O2 and t-BOOH treatment indicating antioxidant potential. On the other hand, concentrations higher than 0.1 μM increase TBARS formation and inhibited superoxide dismutase (SOD) activity, suggesting pro-oxidative effect of this compound at high concentrations. Our results suggest that DPDT presents antigenotoxic and antimutagenic properties at concentration range of 0.01-0.1 μM. The protection effect could be attributed to antioxidant capacity of DPDT at this concentration range in V79 cells. PMID:26001756

  11. Roles of small, acid-soluble spore proteins and core water content in survival of Bacillus subtilis spores exposed to environmental solar UV radiation.

    PubMed

    Moeller, Ralf; Setlow, Peter; Reitz, Günther; Nicholson, Wayne L

    2009-08-01

    Spores of Bacillus subtilis contain a number of small, acid-soluble spore proteins (SASP) which comprise up to 20% of total spore core protein. The multiple alpha/beta-type SASP have been shown to confer resistance to UV radiation, heat, peroxides, and other sporicidal treatments. In this study, SASP-defective mutants of B. subtilis and spores deficient in dacB, a mutation leading to an increased core water content, were used to study the relative contributions of SASP and increased core water content to spore resistance to germicidal 254-nm and simulated environmental UV exposure (280 to 400 nm, 290 to 400 nm, and 320 to 400 nm). Spores of strains carrying mutations in sspA, sspB, and both sspA and sspB (lacking the major SASP-alpha and/or SASP-beta) were significantly more sensitive to 254-nm and all polychromatic UV exposures, whereas the UV resistance of spores of the sspE strain (lacking SASP-gamma) was essentially identical to that of the wild type. Spores of the dacB-defective strain were as resistant to 254-nm UV-C radiation as wild-type spores. However, spores of the dacB strain were significantly more sensitive than wild-type spores to environmental UV treatments of >280 nm. Air-dried spores of the dacB mutant strain had a significantly higher water content than air-dried wild-type spores. Our results indicate that alpha/beta-type SASP and decreased spore core water content play an essential role in spore resistance to environmentally relevant UV wavelengths whereas SASP-gamma does not.

  12. Transformation of avobenzone in conditions of aquatic chlorination and UV-irradiation.

    PubMed

    Trebše, Polonca; Polyakova, Olga V; Baranova, Maria; Kralj, Mojca Bavcon; Dolenc, Darko; Sarakha, Mohamed; Kutin, Alexander; Lebedev, Albert T

    2016-09-15

    Emerging contaminants represent a wide group of the most different compounds. They appear in the environment at trace levels due to human activity. Most of these compounds are not yet regulated. Sunscreen UV-filters play an important role among these emerging contaminants. In the present research the reactions of 4-tert-butyl-4'-methoxydibenzoylmethane (avobenzone), the most common UV filter in the formulation of sunscreens, were studied under the combined influence of active chlorine and UV-irradiation. Twenty five compounds were identified by GC/MS as transformation products of avobenzone in reactions of aquatic UV-irradiation and chlorination with sodium hypochlorite. A complete scheme of transformation of avobenzone covering all the semivolatile products is proposed. The identification of the two primary chlorination products (2-chloro-1-(4-tert-butylphenyl)-3-(4-methoxyphenyl)-1,3-propanedione and 2,2-dichloro-1-(4-tert-butylphenyl)-3-(4-methoxyphenyl)-1,3-propanedione) was confirmed by their synthesis and GC/MS and NMR analysis. Although the toxicities of the majority of these products remain unknown substituted chlorinated phenols and acetophenones are known to be rather toxic. Combined action of active chlorine and UV-irradiation results in the formation of some products (chloroanhydrides, chlorophenols) not forming in conditions of separate application of these disinfection methods. Therefore caring for people «well-being» it is of great importance to apply the most appropriate disinfection method. Since the primary transformation products partially resist powerful UV-C irradiation they may be treated as stable and persistent pollutants.

  13. 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

  14. 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

  15. 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

  16. 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.

  17. Methodology of the Efficiency Factors of Fine Grained Clayish Suspensions Separation in Multileveled Hydrocyclone Systems / Metodyka Oceny DOKŁADNOŚCI ROZDZIAŁU Drobno Uziarnionych Zawiesin Ilastych W Wielostopniowych UKŁADACH HYDROCYKLONÓW

    NASA Astrophysics Data System (ADS)

    Nowak, Alicja; Surowiak, Agnieszka

    2013-12-01

    individual overflows and high separation efficiency - if the contents of this fraction in the feed of 1st classification level is very small. Applying the Hancock equation (1) the technological efficiency of obtaining fraction < 20 μm and < 2 μm in hydrocyclones overflows was calculated. Konieczność uzyskiwania całego szeregu gatunków produktów różniących się uziarnieniem wymaga - w znacznie większym stopniu niż w przypadku większości innych procesów przeróbczych - budowania złożonych, wielostopniowych układów technologicznych klasyfikacji. Mogą się one składać z operacji realizowanych przy użyciu urządzeń klasyfikujących różnych typów, bądź też urządzeń tego samego typu o takich samych lub różnych parametrach konstrukcyjnych. W pracy przedstawiono wyniki badań trójstopniowego procesu rozdziału zawiesiny o uziarnieniu fazy stałej < 60 μm w hydrocyklonach o średnicy części cylindrycznej D = 30 mm w dwóch seriach badań. Porównano efekty klasyfikacji m.in. takie jak: skuteczność rozdziału, uzyski i straty klas najdrobniejszych w produktach rozdziału, wielkości otrzymywanych ziaren podziałowych i wskaźniki dokładności rozdziału w przypadku gdy średnice dysz wylewowych hydrocyklonów były takie same w każdym stopniu klasyfikacji oraz w przypadku gdy średnice te zwiększały się w kolejnych stopniach rozdziału. Zasadniczym celem pracy była próba opisu rzeczywistych krzywych rozdziału uzyskanych z doświadczeń funkcjami modelowymi dla różnych warunków pracy układu hydrocyklonów. Do wyznaczenia charakterystyk rozdziału użyto funkcji aproksymujących empiryczne krzywe rozdziału. Były to: funkcja opisująca dystrybuantę rozkładu Weibulla dla doświadczeń serii „a" (wzór 8) i funkcja opisująca dystrybuantę rozkładu logistycznego dla doświadczeń serii „b" (wzór 9). W oparciu o aproksymowane krzywe rozdziału wyliczono wskaźniki ostrości rozdziału: rozproszenie prawdopodobne (Ep), imperfekcj

  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. Visualization of Multidimensional Data in Purpose of Qualitative Classification of Various Types of Coal / Wizualizacja Wielowymiarowych Danych W Celu Klasyfikacji JAKOŚCIOWEJ RÓŻNYCH TYPÓW WĘGLA

    NASA Astrophysics Data System (ADS)

    Niedoba, Tomasz; Jamróz, Dariusz

    2013-12-01

    . Surowce mineralne, które podlegają wzbogacaniu w celu ich lepszego wykorzystania mogą być (charakteryzują się) charakteryzowane wieloma wskaźnikami opisującymi ich, interesujące przeróbkarza, cechy. Podstawowymi cechami są wielkość ziaren oraz ich gęstość, które decydują o przebiegu rozdziału zbiorów ziaren (nadaw) i efektach takiego rozdziału. Rozdział prowadzi się z reguły, w celu uzyskania produktów o zróżnicowanych wartościach średnich wybranej cechy, która zwykle charakteryzowana jest zawartością określonego składnika surowca wyznaczoną na drodze analiz chemicznych. Takie podejście do surowca mineralnego prowadzi do 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 & Surowiak, 2012); - wielowymiarowe równania regresji wraz z analizą macierzy współczynników korelacji liniowej oraz korelacji cząstkowej (Niedoba, 2013); - analiza czynnikowa (Tumidajski & Saramak, 2009); - inne metody, w tym wizualizacja metodą tuneli obserwacyjnych (Jamróz, 2001), osi równoległych oraz wizualizacja zależności pomiędzy wielowymiarowymi bryłami (Jamróz, 2009). Wielowymiarowe rozkłady wektora X traktowanego jako wektor losowy, mają już swoją bogatą literaturę i praktyczne ich zastosowanie i nie będą przedmiotem tej publikacji. Pozostałe metody są ze sobą w pewien sposób powiązane, co skrótowo zostało przedstawione w artykule. Macierze współczynników korelacji liniowej i współczynników korelacji cząstkowej są związane, z reguły, z istniejącymi modelami liniowymi zależności występujących mi

  20. 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

  1. 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

  2. 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

  3. Influence of the Plow Filling and Thread Angle onto the Plow Head Efficiency / Wpływ Współczynnika Wypełnienia Organu Oraz Kąta Nawinięcia Płata Ślimaka Na Sprawność Ładowania Frezującymi Organami Ślimakowymi

    NASA Astrophysics Data System (ADS)

    Wydro, Tomasz

    2015-03-01

    Laboratory examinations on the plow heads at various filling rate and material grain-size, as well as various values of worm thread angle of the plow head have been executed. Influence of the worm thread angle and plow head filling onto optimal loading efficiency, has also been tested. Eksploatacja węgla kamiennego w Polsce odbywa się przy zastosowaniu kompleksów ścianowych kombajnowych jak również kompleksów strugowych. Ten drugi z kompleksów jest znacznie mniej rozpowszechniony w Polsce i stosowany do pokładów o miąższości poniżej 1,5 m. Do głównych maszyn i urządzeń ścianowego kompleksu kombajnowego należy zaliczyć maszynę urabiająco - ładującą jaką jest kombajn ścianowy, obudowę zmechanizowaną oraz przenośnik ścianowy. Elementami roboczymi w kombajnie ścianowym są frezujące organy ślimakowe, które mocowane są na ramionach kombajnu. Zadaniem frezujących organów ślimakowych jest realizacja jednocześnie dwóch procesów. Pierwszym z procesów jest frezowanie czyli oddzielanie kawałków węgla od calizny. Drugi proces to proces ładowania urobku, polegający na ciągłym odprowadzaniu urobku na przenośnik ścianowy. Równoległość realizacji pracy tych dwóch procesów, uniemożliwia w warunkach rzeczywistych przeprowadzenie obserwacji procesu ładowania i dokonania jakichkolwiek pomiarów i analiz. Dlatego też, przeprowadzane badania i pomiary opisywane w literaturze zwykle miały charakter modelowy lub stanowiskowy, gdyż tylko takie warunki umożliwiały rozdział tych funkcji organu (Chodura, 1992; Hyong Jong Gol, 1990; Jaszczuk & Tomaszewski, 2004; Krauze, 1997). W związku z powyższym, chcąc bliżej poznać prawa rządzące procesem ładowania, zdecydowano się na rozdzielenie tych dwóch procesów i przeprowadzenie badań laboratoryjnych. Przedmiotowe badania zostały przeprowadzone w laboratorium Katedry Maszyn Górniczych, Przeróbczych i Transportowych AGH. W badaniach uwzgl

  4. 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

  5. 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

  6. 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.

  7. Measurement of Small Values of Hydrostatic Pressure with the Compensation of Atmospheric Pressure Influence / Pomiar Małych Wartości Ciśnienia Hydrostaty