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  1. Mobile gene silencing in Arabidopsis is regulated by hydrogen peroxide

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    Dacheng Liang

    2014-12-01

    Full Text Available In plants and nematodes, RNAi can spread from cells from which it is initiated to other cells in the organism. The underlying mechanism controlling the mobility of RNAi signals is not known, especially in the case of plants. A genetic screen designed to recover plants impaired in the movement but not the production or effectiveness of the RNAi signal identified RCI3, which encodes a hydrogen peroxide (H2O2-producing type III peroxidase, as a key regulator of silencing mobility in Arabidopsis thaliana. Silencing initiated in the roots of rci3 plants failed to spread into leaf tissue or floral tissue. Application of exogenous H2O2 reinstated the spread in rci3 plants and accelerated it in wild-type plants. The addition of catalase or MnO2, which breaks down H2O2, slowed the spread of silencing in wild-type plants. We propose that endogenous H2O2, under the control of peroxidases, regulates the spread of gene silencing by altering plasmodesmata permeability through remodelling of local cell wall structure, and may play a role in regulating systemic viral defence.

  2. Hydrogen peroxide sensing, signaling and regulation of transcription factors

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    Marinho, H. Susana; Real, Carla; Cyrne, Luísa; Soares, Helena; Antunes, Fernando

    2014-01-01

    The regulatory mechanisms by which hydrogen peroxide (H2O2) modulates the activity of transcription factors in bacteria (OxyR and PerR), lower eukaryotes (Yap1, Maf1, Hsf1 and Msn2/4) and mammalian cells (AP-1, NRF2, CREB, HSF1, HIF-1, TP53, NF-κB, NOTCH, SP1 and SCREB-1) are reviewed. The complexity of regulatory networks increases throughout the phylogenetic tree, reaching a high level of complexity in mammalians. Multiple H2O2 sensors and pathways are triggered converging in the regulation of transcription factors at several levels: (1) synthesis of the transcription factor by upregulating transcription or increasing both mRNA stability and translation; (ii) stability of the transcription factor by decreasing its association with the ubiquitin E3 ligase complex or by inhibiting this complex; (iii) cytoplasm–nuclear traffic by exposing/masking nuclear localization signals, or by releasing the transcription factor from partners or from membrane anchors; and (iv) DNA binding and nuclear transactivation by modulating transcription factor affinity towards DNA, co-activators or repressors, and by targeting specific regions of chromatin to activate individual genes. We also discuss how H2O2 biological specificity results from diverse thiol protein sensors, with different reactivity of their sulfhydryl groups towards H2O2, being activated by different concentrations and times of exposure to H2O2. The specific regulation of local H2O2 concentrations is also crucial and results from H2O2 localized production and removal controlled by signals. Finally, we formulate equations to extract from typical experiments quantitative data concerning H2O2 reactivity with sensor molecules. Rate constants of 140 M−1 s−1 and ≥1.3 × 103 M−1 s−1 were estimated, respectively, for the reaction of H2O2 with KEAP1 and with an unknown target that mediates NRF2 protein synthesis. In conclusion, the multitude of H2O2 targets and mechanisms provides an opportunity for highly

  3. Hydrogen peroxide sensing, signaling and regulation of transcription factors

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    H. Susana Marinho

    2014-01-01

    Full Text Available The regulatory mechanisms by which hydrogen peroxide (H2O2 modulates the activity of transcription factors in bacteria (OxyR and PerR, lower eukaryotes (Yap1, Maf1, Hsf1 and Msn2/4 and mammalian cells (AP-1, NRF2, CREB, HSF1, HIF-1, TP53, NF-κB, NOTCH, SP1 and SCREB-1 are reviewed. The complexity of regulatory networks increases throughout the phylogenetic tree, reaching a high level of complexity in mammalians. Multiple H2O2 sensors and pathways are triggered converging in the regulation of transcription factors at several levels: (1 synthesis of the transcription factor by upregulating transcription or increasing both mRNA stability and translation; (ii stability of the transcription factor by decreasing its association with the ubiquitin E3 ligase complex or by inhibiting this complex; (iii cytoplasm–nuclear traffic by exposing/masking nuclear localization signals, or by releasing the transcription factor from partners or from membrane anchors; and (iv DNA binding and nuclear transactivation by modulating transcription factor affinity towards DNA, co-activators or repressors, and by targeting specific regions of chromatin to activate individual genes. We also discuss how H2O2 biological specificity results from diverse thiol protein sensors, with different reactivity of their sulfhydryl groups towards H2O2, being activated by different concentrations and times of exposure to H2O2. The specific regulation of local H2O2 concentrations is also crucial and results from H2O2 localized production and removal controlled by signals. Finally, we formulate equations to extract from typical experiments quantitative data concerning H2O2 reactivity with sensor molecules. Rate constants of 140 M−1 s−1 and ≥1.3 × 103 M−1 s−1 were estimated, respectively, for the reaction of H2O2 with KEAP1 and with an unknown target that mediates NRF2 protein synthesis. In conclusion, the multitude of H2O2 targets and mechanisms provides an opportunity for

  4. Hydrogen peroxide prevents vascular calcification induced ROS production by regulating Nrf-2 pathway.

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    Zhang, Wensong; Li, Yi; Ding, Hanlu; Du, Yaqin; Wang, Li

    2016-08-01

    Although vascular calcification in end-stage renal disease (ESRD) represents a ubiquitous human health problem, effective therapies with limited side effects are still lacking, and the precise mechanisms are not fully understood. The Nrf-2/ARE pathway is a pivotal to regulate anti-oxidative responses in vascular calcification upon ESRD. Although Nrf-2 plays a crucial role in atherosclerosis, pulmonary fibrosis, and brain ischemia, the effect of Nrf-2 and oxidative stress on vascular calcification in ESRD patients is still unclear. The aim of this research was to study the protective role of hydrogen peroxide in vascular calcification and the mechanism of Nrf-2 and oxidative stress on vascular calcification. Here we used the rat vascular smooth muscle cell model of β-glycerophosphate-induced calcification resembling vascular calcification in ESRD to investigate the therapeutic effect of 0.01 mM hydrogen peroxide on vascular calcification and further explores the possible underlying mechanisms. Our current report shows the in vitro role of 0.01 mM hydrogen peroxide in protecting against intracellular ROS accumulation upon vascular calcification. Both hydrogen peroxide and sulforaphane pretreatment reduced ROS production, increased the expression of Nrf-2, and decreased the expression of Runx2 following calcification. Our study demonstrates that 0.01 mM hydrogen peroxide can effectively protect rat aortic vascular smooth muscle cells against oxidative stress by preventing vascular calcification induced ROS production through Nrf-2 pathway. These data might define an antioxidant role of hydrogen peroxide in vascular calcification upon ESRD.

  5. Light-activated regulation of cofilin dynamics using a photocaged hydrogen peroxide generator.

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    Miller, Evan W; Taulet, Nicolas; Onak, Carl S; New, Elizabeth J; Lanselle, Julie K; Smelick, Gillian S; Chang, Christopher J

    2010-12-08

    Hydrogen peroxide (H2O2) can exert diverse signaling and stress responses within living systems depending on its spatial and temporal dynamics. Here we report a new small-molecule probe for producing H2O2 on demand upon photoactivation and its application for optical regulation of cofilin-actin rod formation in living cells. This chemical method offers many potential opportunities for dissecting biological roles for H2O2 as well as remote control of cell behavior via H2O2-mediated pathways.

  6. Electrochemical Hydrogen Peroxide Generator

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    Tennakoon, Charles L. K.; Singh, Waheguru; Anderson, Kelvin C.

    2010-01-01

    Two-electron reduction of oxygen to produce hydrogen peroxide is a much researched topic. Most of the work has been done in the production of hydrogen peroxide in basic media, in order to address the needs of the pulp and paper industry. However, peroxides under alkaline conditions show poor stabilities and are not useful in disinfection applications. There is a need to design electrocatalysts that are stable and provide good current and energy efficiencies to produce hydrogen peroxide under acidic conditions. The innovation focuses on the in situ generation of hydrogen peroxide using an electrochemical cell having a gas diffusion electrode as the cathode (electrode connected to the negative pole of the power supply) and a platinized titanium anode. The cathode and anode compartments are separated by a readily available cation-exchange membrane (Nafion 117). The anode compartment is fed with deionized water. Generation of oxygen is the anode reaction. Protons from the anode compartment are transferred across the cation-exchange membrane to the cathode compartment by electrostatic attraction towards the negatively charged electrode. The cathode compartment is fed with oxygen. Here, hydrogen peroxide is generated by the reduction of oxygen. Water may also be generated in the cathode. A small amount of water is also transported across the membrane along with hydrated protons transported across the membrane. Generally, each proton is hydrated with 3-5 molecules. The process is unique because hydrogen peroxide is formed as a high-purity aqueous solution. Since there are no hazardous chemicals or liquids used in the process, the disinfection product can be applied directly to water, before entering a water filtration unit to disinfect the incoming water and to prevent the build up of heterotrophic bacteria, for example, in carbon based filters. The competitive advantages of this process are: 1. No consumable chemicals are needed in the process. The only raw materials

  7. Redox Regulation of the Tumor Suppressor PTEN by Hydrogen Peroxide and Tert-Butyl Hydroperoxide

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    Ying Zhang

    2017-05-01

    Full Text Available Organic peroxides and hydroperoxides are skin tumor promoters. Free radical derivatives from these compounds are presumed to be the prominent mediators of tumor promotion. However, the molecular targets of these species are unknown. Phosphatase and tensin homologs deleted on chromosome 10 (PTEN are tumor suppressors that play important roles in cell growth, proliferation, and cell survival by negative regulation of phosphoinositol-3-kinase/protein kinase B signaling. PTEN is reversibly oxidized in various cells by exogenous and endogenous hydrogen peroxide. Oxidized PTEN is converted back to the reduced form by cellular reducing agents, predominantly by the thioredoxin (Trx system. Here, the role of tert-butyl hydroperoxide (t-BHP in redox regulation of PTEN was analyzed by using cell-based and in vitro assays. Exposure to t-BHP led to oxidation of recombinant PTEN. In contrast to H2O2, PTEN oxidation by t-BHP was irreversible in HeLa cells. However, oxidized PTEN was reduced by exogenous Trx system. Taken together, these results indicate that t-BHP induces PTEN oxidation and inhibits Trx system, which results in irreversible PTEN oxidation in HeLa cells. Collectively, these results suggest a novel mechanism of t-BHP in the promotion of tumorigenesis.

  8. Opi1p translocation to the nucleus is regulated by hydrogen peroxide in Saccharomyces cerevisiae.

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    Camelo, Carolina; Vilas-Boas, Filipe; Cepeda, Andreia Pereira; Real, Carla; Barros-Martins, Joana; Pinto, Francisco; Soares, Helena; Marinho, H Susana; Cyrne, Luisa

    2017-09-01

    During exposure of yeast cells to low levels of hydrogen peroxide (H2 O2 ), the expression of several genes is regulated for cells to adapt to the surrounding oxidative environment. Such adaptation involves modification of plasma membrane lipid composition, reorganization of ergosterol-rich microdomains and altered gene expression of proteins involved in lipid and vesicle traffic, to decrease permeability to exogenous H2 O2 . Opi1p is a transcriptional repressor that is inactive when present at the nuclear membrane/endoplasmic reticulum, but represseses transcription of inositol upstream activating sequence (UASINO )-containing genes, many of which are involved in the synthesis of phospholipids and fatty acids, when it is translocated to the nucleus. We investigated whether H2 O2 in concentrations inducing adaptation regulates Opi1p function. We found that, in the presence of H2 O2 , GFP-Opi1p fusion protein translocates to the nucleus and, concomitantly, the expression of UASINO -containing genes is affected. We also investigated whether cysteine residues of Opi1p were implicated in the H2 O2 -mediated translocation of this protein to the nucleus and identified cysteine residue 159 as essential for this process. Our work shows that Opi1p is redox-regulated and establishes a new mechanism of gene regulation involving Opi1p, which is important for adaptation to H2 O2 in yeast cells. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  9. Laccase-13 Regulates Seed Setting Rate by Affecting Hydrogen Peroxide Dynamics and Mitochondrial Integrity in Rice

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    Yang Yu

    2017-07-01

    Full Text Available Seed setting rate is one of the most important components of rice grain yield. To date, only several genes regulating setting rate have been identified in plant. In this study, we showed that laccase-13 (OsLAC13, a member of laccase family genes which are known for their roles in modulating phenylpropanoid pathway and secondary lignification in cell wall, exerts a regulatory function in rice seed setting rate. OsLAC13 expressed in anthers and promotes hydrogen peroxide production both in vitro and in the filaments and anther connectives. Knock-out of OsLAC13 showed significantly increased seed setting rate, while overexpression of this gene exhibited induced mitochondrial damage and suppressed sugar transportation in anthers, which in turn affected seed setting rate. OsLAC13 also induced H2O2 production and mitochondrial damage in the root tip cells which caused the lethal phenotype. We also showed that high abundant of OsmiR397, the suppressor of OsLAC13 mRNA, increased the seed setting rate of rice plants, and restrains H2O2 accumulation in roots during oxidative stress. Our results suggested a novel regulatory role of OsLAC13 gene in regulating seed setting rate by affecting H2O2 dynamics and mitochondrial integrity in rice.

  10. Aspergillus fumigatus allergen expression is coordinately regulated in response to hydrogen peroxide and cyclic AMP

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    Bowyer Paul

    2010-11-01

    Full Text Available Abstract Background A. fumigatus has been associated with a wide spectrum of allergic disorders such as ABPA or SAFS. It is poorly understood what allergens in particular are being expressed during fungal invasion and which are responsible for stimulation of immune responses. Study of the dynamics of allergen production by fungi may lead to insights into how allergens are presented to the immune system. Methods Expression of 17 A. fumigatus allergen genes was examined in response to various culture conditions and stimuli as well as in the presence of macrophages in order to mimic conditions encountered in the lung. Results Expression of 14/17 allergen genes was strongly induced by oxidative stress caused by hydrogen peroxide (Asp f 1, -2, -4, -5, -6, -7, -8, -10, -13, -17 and -18, all >10-fold and Asp f 11, -12, and -22, 5-10-fold and 16/17 allergen genes were repressed in the presence of cAMP. The 4 protease allergen genes (Asp f -5, -10, -13 and -18 were expressed at very low levels compared to the comparator (β-tubulin under all other conditions examined. Mild heat shock, anoxia, lipid and presence of macrophages did not result in coordinated changes in allergen gene expression. Growth on lipid as sole carbon source contributed to the moderate induction of most of the allergen genes. Heat shock (37°C > 42°C caused moderate repression in 11/17 genes (Asp f 1, -2, -4, -5, -6, -9, -10, -13, -17, -18 and -23 (2- to 9-fold, which was mostly evident for Asp f 1 and -9 (~9-fold. Anaerobic stress led to moderate induction of 13/17 genes (1.1 to 4-fold with one, Asp f 8 induced over 10-fold when grown under mineral oil. Complex changes were seen in gene expression during co-culture of A. fumigatus with macrophages. Conclusions Remarkable coordination of allergen gene expression in response to a specific condition (oxidative stress or the presence of cAMP has been observed, implying that a single biological stimulus may play a role in allergen gene

  11. Laminarin protects against hydrogen peroxide-induced oxidative damage in MRC-5 cells possibly via regulating NRF2

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    Xue Liu

    2017-07-01

    Full Text Available Oxidative damage is a major cause of lung diseases, including pulmonary fibrosis. Laminarin is a kind of polysaccharide extracted from brown algae and plays vital roles in various biological processes. However, the functions and mechanisms of laminarin in pulmonary oxidative damage are poorly understood. This study aimed at investigating the protective effect of laminarin against pulmonary oxidative damage and underlying mechanisms. Human lung fibroblasts MRC-5 cells were treated with hydrogen peroxide to induce oxidative damage. Laminarin treatment was performed before or after hydrogen peroxide treatment, and then major indexes of oxidative damage, including superoxide dismutase (SOD, malondialdehyde (MDA, reduced glutathione (GSH and catalase (CAT, were quantified by biochemical assays. The expression of oxidation-related factor, nuclear factor erythroid 2 like 2 (NRF2 was analyzed by qPCR, Western blot and immunofluorescence assay. NRF2 knockdown and overexpression were performed by cell transfection to reveal possible mechanisms. Results showed that laminarin treatment of 0.020 mg/mL for 24 h, especially the pre-treatment, could significantly relieve changes in SOD, MDA, GSH and CAT that were altered by hydrogen peroxide, and promote NRF2 mRNA (P < 0.001. NRF2 protein was also elevated by laminarin, and nuclear translocation was observed. Factors in NRF2 signaling pathways, including KEAP1, NQO1, GCLC and HO1, were all regulated by laminarin. Roles of NRF2 were tested, suggesting that NRF2 regulated the concentration of SOD, MDA, GSH and CAT, suppressed KEAP1, and promoted NQO1, GCLC and HO1. These findings suggested the protective role of laminarin against pulmonary oxidative damage, which might involve the regulation of NRF2 signaling pathways. This study provided information for the clinical application of laminarin to pulmonary diseases like pulmonary fibrosis.

  12. Hydrogen peroxide effects on root hydraulic properties and plasma membrane aquaporin regulation in Phaseolus vulgaris.

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    Benabdellah, Karim; Ruiz-Lozano, Juan Manuel; Aroca, Ricardo

    2009-08-01

    In the last few years, the role of reactive oxygen species as signaling molecules has emerged, and not only as damage-related roles. Here, we analyzed how root hydraulic properties were modified by different hydrogen peroxide (H2O2) concentrations applied exogenously to the root medium. Two different experimental setups were employed: Phaseolus vulgaris plants growing in hydroponic or in potted soils. In both experimental setups, we found an increase of root hydraulic conductance (L) in response to H2O2 application for the first time. Twenty millimolar was the threshold concentration of H2O2 for observing an effect on L in the soil experiment, while in the hydroponic experiment, a positive effect on L was observed at 0.25 mM H2O2. In the hydroponic experiment, a correlation between increased L and plasma membrane aquaporin amount and their root localization was observed. These findings provide new insights to study how several environmental factors modify L.

  13. Improved Electrolytic Hydrogen Peroxide Generator

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    James, Patrick I.

    2005-01-01

    An improved apparatus for the electrolytic generation of hydrogen peroxide dissolved in water has been developed. The apparatus is a prototype of H2O2 generators for the safe and effective sterilization of water, sterilization of equipment in contact with water, and other applications in which there is need for hydrogen peroxide at low concentration as an oxidant. Potential applications for electrolytic H2O2 generators include purification of water for drinking and for use in industrial processes, sanitation for hospitals and biotechnological industries, inhibition and removal of biofouling in heat exchangers, cooling towers, filtration units, and the treatment of wastewater by use of advanced oxidation processes that are promoted by H2O2.

  14. Allelic variation partially regulates galactose-dependent hydrogen peroxide release from circulating hemocytes of the snail Biomphalaria glabrata.

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    Allan, Euan R O; Blouin, Michael S

    2018-01-01

    Freshwater snails are the intermediate hosts for numerous parasitic worms that are detrimental to human and agricultural health. Understanding the immune responses of these snails could be vital for finding ways to block transmission of those parasites. Allelic variation in a recently discovered genomic region in the snail, Biomphalaria glabrata, influences their susceptibility to schistosomes. Here we tested whether genes in that region, termed the Guadeloupe Resistance Complex (GRC), are involved in recognition of common pathogen-associated molecules that have been shown to be stimulants of the hydrogen peroxide defense pathway. We show that hemocytes extracted from individuals with one of the three GRC genotypes released less hydrogen peroxide than the other two genotypes, after stimulation with galactose. This difference was not observed after stimulation with several other microbial-associated carbohydrates, despite those ligands sharing the same putative pathway for hydrogen peroxide release. Therefore, we conclude that allelic variation in the GRC region may influence the recognition of galactose, rather than the conserved downstream steps in the hydrogen peroxide pathway. These results thus are consistent with the hypothesis that proteins produced by this region are involved in pathogen recognition. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Hydrogen peroxide and nitric oxide regulation of phenolic metabolism under water stress and ABA in wheat.

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    Kaur, Rattanpreet; Zhawar, Vikramjit Kaur

    2017-06-01

    Wheat cultivar PBW644 (drought tolerant) and PBW343 (drought sensitive) were found as ABA-higher sensitive and ABA-lesser sensitive, respectively, in the screen of six wheat cultivars. Both cultivars were studied for H2O2 (ROS)/nitric oxide (NO)-regulation of growth and phenolic metabolism under ABA and water stress (WS) by supplying ROS/NO producers as well as scavengers. Endogenous ROS/NO under ABA/WS increased growth, such effect was higher in PBW644. In PBW343, reduced growth under WS was improved by exogenous ROS/NO. Exogenous ROS/NO under ABA/WS decreased lignin and increased phenolics in PBW343 but such relation was not found in PBW644. Endogenous NO under WS increased flavonoids in both cultivars. Both ROS/NO under ABA/WS increased flavonoids in PBW644, however, in PBW343, only ROS increased these in roots. Under WS, PBW644 showed higher levels of cell wall peroxidase (CW-POX) and lower levels of soluble peroxidase (S-POX) than PBW343. However, under ABA, it showed higher levels of both peroxidases. ROS/NO signals under ABA increased both types of POX in both cultivars while under WS, these signals increased both types in PBW343 but CW-POX only in PBW644. Polyphenol oxidases were ABA-upregulated in PBW644 only. Under WS, these enzymes were maintained higher in PBW343. This study indicated that tolerant cultivar under WS contained sufficient endogenous ROS/NO signalling to which susceptible cultivar lacked but showed improvement on exogenous applications. Secondly, tolerant cultivar was using less phenolic activity under WS which could be due to the presence of sufficient levels of primary antioxidants.

  16. Hydrogen Peroxide as a Sustainable Energy Carrier: Electrocatalytic Production of Hydrogen Peroxide and the Fuel Cell.

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    Fukuzumi, Shunichi; Yamada, Yusuke; Karlin, Kenneth D

    2012-11-01

    This review describes homogeneous and heterogeneous catalytic reduction of dioxygen with metal complexes focusing on the catalytic two-electron reduction of dioxygen to produce hydrogen peroxide. Whether two-electron reduction of dioxygen to produce hydrogen peroxide or four-electron O2-reduction to produce water occurs depends on the types of metals and ligands that are utilized. Those factors controlling the two processes are discussed in terms of metal-oxygen intermediates involved in the catalysis. Metal complexes acting as catalysts for selective two-electron reduction of oxygen can be utilized as metal complex-modified electrodes in the electrocatalytic reduction to produce hydrogen peroxide. Hydrogen peroxide thus produced can be used as a fuel in a hydrogen peroxide fuel cell. A hydrogen peroxide fuel cell can be operated with a one-compartment structure without a membrane, which is certainly more promising for the development of low-cost fuel cells as compared with two compartment hydrogen fuel cells that require membranes. Hydrogen peroxide is regarded as an environmentally benign energy carrier because it can be produced by the electrocatalytic two-electron reduction of O2, which is abundant in air, using solar cells; the hydrogen peroxide thus produced could then be readily stored and then used as needed to generate electricity through the use of hydrogen peroxide fuel cells.

  17. Hydrogen Peroxide as a Sustainable Energy Carrier: Electrocatalytic Production of Hydrogen Peroxide and the Fuel Cell

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    Fukuzumi, Shunichi; Yamada, Yusuke; Karlin, Kenneth D.

    2012-01-01

    This review describes homogeneous and heterogeneous catalytic reduction of dioxygen with metal complexes focusing on the catalytic two-electron reduction of dioxygen to produce hydrogen peroxide. Whether two-electron reduction of dioxygen to produce hydrogen peroxide or four-electron O2-reduction to produce water occurs depends on the types of metals and ligands that are utilized. Those factors controlling the two processes are discussed in terms of metal-oxygen intermediates involved in the catalysis. Metal complexes acting as catalysts for selective two-electron reduction of oxygen can be utilized as metal complex-modified electrodes in the electrocatalytic reduction to produce hydrogen peroxide. Hydrogen peroxide thus produced can be used as a fuel in a hydrogen peroxide fuel cell. A hydrogen peroxide fuel cell can be operated with a one-compartment structure without a membrane, which is certainly more promising for the development of low-cost fuel cells as compared with two compartment hydrogen fuel cells that require membranes. Hydrogen peroxide is regarded as an environmentally benign energy carrier because it can be produced by the electrocatalytic two-electron reduction of O2, which is abundant in air, using solar cells; the hydrogen peroxide thus produced could then be readily stored and then used as needed to generate electricity through the use of hydrogen peroxide fuel cells. PMID:23457415

  18. Phosphorylation and subcellular localization of p27Kip1 regulated by hydrogen peroxide modulation in cancer cells.

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    Irene L Ibañez

    Full Text Available The Cyclin-dependent kinase inhibitor 1B (p27Kip1 is a key protein in the decision between proliferation and cell cycle exit. Quiescent cells show nuclear p27Kip1, but this protein is exported to the cytoplasm in response to proliferating signals. We recently reported that catalase treatment increases the levels of p27Kip1 in vitro and in vivo in a murine model. In order to characterize and broaden these findings, we evaluated the regulation of p27Kip1 by hydrogen peroxide (H(2O(2 in human melanoma cells and melanocytes. We observed a high percentage of p27Kip1 positive nuclei in melanoma cells overexpressing or treated with exogenous catalase, while non-treated controls showed a cytoplasmic localization of p27Kip1. Then we studied the levels of p27Kip1 phosphorylated (p27p at serine 10 (S10 and at threonine 198 (T198 because phosphorylation at these sites enables nuclear exportation of this protein, leading to accumulation and stabilization of p27pT198 in the cytoplasm. We demonstrated by western blot a decrease in p27pS10 and p27pT198 levels in response to H(2O(2 removal in melanoma cells, associated with nuclear p27Kip1. Melanocytes also exhibited nuclear p27Kip1 and lower levels of p27pS10 and p27pT198 than melanoma cells, which showed cytoplasmic p27Kip1. We also showed that the addition of H(2O(2 (0.1 µM to melanoma cells arrested in G1 by serum starvation induces proliferation and increases the levels of p27pS10 and p27pT198 leading to cytoplasmic localization of p27Kip1. Nuclear localization and post-translational modifications of p27Kip1 were also demonstrated by catalase treatment of colorectal carcinoma and neuroblastoma cells, extending our findings to these other human cancer types. In conclusion, we showed in the present work that H(2O(2 scavenging prevents nuclear exportation of p27Kip1, allowing cell cycle arrest, suggesting that cancer cells take advantage of their intrinsic pro-oxidant state to favor cytoplasmic localization

  19. Ultraviolet absorption cross sections of hydrogen peroxide

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    Lin, C. L.; Rohatgi, N. K.; Demore, W. B.

    1978-01-01

    Absorption cross-sections of hydrogen peroxide vapor and of neutral aqueous solutions of hydrogen peroxide were measured in the wavelength range from 195 to 350 nm at 296 K. The spectrophotometric procedure is described, and the reported cross-sections are compared with values obtained by other researchers. Photodissociation coefficients of atmospheric H2O2 were calculated for direct absorption of unscattered solar radiation, and the vertical distributions of these coefficients are shown for various solar zenith angles.

  20. Hypochlorous acid and hydrogen peroxide-induced negative regulation of Salmonella enterica serovar Typhimurium ompW by the response regulator ArcA

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    Morales Eduardo H

    2012-05-01

    Full Text Available Abstract Background Hydrogen peroxide (H2O2 and hypochlorous acid (HOCl are reactive oxygen species that are part of the oxidative burst encountered by Salmonella enterica serovar Typhimurium (S. Typhimurium upon internalization by phagocytic cells. In order to survive, bacteria must sense these signals and modulate gene expression. Growing evidence indicates that the ArcAB two component system plays a role in the resistance to reactive oxygen species. We investigated the influx of H2O2 and HOCl through OmpW and the role of ArcAB in modulating its expression after exposure to both toxic compounds in S. Typhimurium. Results H2O2 and HOCl influx was determined both in vitro and in vivo. A S. Typhimurium ompW mutant strain (∆ompW exposed to sub-lethal levels of H2O2 and HOCl showed a decreased influx of both compounds as compared to a wild type strain. Further evidence of H2O2 and HOCl diffusion through OmpW was obtained by using reconstituted proteoliposomes. We hypothesized that ompW expression should be negatively regulated upon exposure to H2O2 and HOCl to better exclude these compounds from the cell. As expected, qRT-PCR showed a negative regulation in a wild type strain treated with sub-lethal concentrations of these compounds. A bioinformatic analysis in search for potential negative regulators predicted the presence of three ArcA binding sites at the ompW promoter region. By electrophoretic mobility shift assay (EMSA and using transcriptional fusions we demonstrated an interaction between ArcA and one site at the ompW promoter region. Moreover, qRT-PCR showed that the negative regulation observed in the wild type strain was lost in an arcA and in arcB mutant strains. Conclusions OmpW allows the influx of H2O2 and HOCl and is negatively regulated by ArcA by direct interaction with the ompW promoter region upon exposure to both toxic compounds.

  1. Cinnamon polyphenols attenuate the hydrogen peroxide-induced down regulation of S100β secretion by regulating sirtuin 1 in C6 rat glioma cells.

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    Qin, Bolin; Panickar, Kiran S; Anderson, Richard A

    2014-04-25

    It is well established that the brain is particularly susceptible to oxidative damage due to its high consumption of oxygen. The objective of this study was to investigate the protective effects of a water soluble polyphenol-rich extract of cinnamon and the possible mechanisms, under conditions of oxidative stress-induced by hydrogen peroxide, in rat C6 glioma cells. After 24h of H2O2 incubation, the secretion and intracellular expression of S100β were determined by immunoprecitation/immunoblotting and immunofluorescence imaging. Cinnamon polyphenols (CP) counteracted the oxidative effects of H2O2 on S100β secretion and expression. CP also enhanced the impaired protein levels of sirtuins 1, 2, and 3, which are deacetylases important in cell survival. H2O2 also induced the overexpression of the proinflammatory factors, TNF-α, phospho-NF-κB p65, as well as of Bcl-xl, Bax and Caspase-3, which are all the members of the Bcl-2 family. CP not only suppressed the expression of these proteins but also attenuated the phosphorylation induced by H2O2. CP also upregulated the decreased Bcl-2 protein levels in H2O2 treated C6 cells. The effects of CP on H2O2-induced downregulation of S100β secretion were blocked by SIRT1 siRNA demonstrating that SIRT1 plays a regulatory role in CP-mediated prevention by H2O2. These data demonstrate that Cinnamon polyphenols may exert neuroprotective effects in glial cells by the regulation of Bcl-2 family members and enhancing SIRT1 expression during oxidative stress. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. EFFECT OF HYDROGEN PEROXIDE AND THIOUREA ON ...

    African Journals Online (AJOL)

    ACSS

    2013-07-03

    Jul 3, 2013 ... temperature and humidity. The objective of this study was to evaluate the involvement of hydrogen peroxide (by direct or indirect application of thiourea, a catalase inhibitor) in dormancy release and sprouting of potato microtubers and tubers was evaluated using two complementary experiments. First, the ...

  3. Virucidal efficacy of hydrogen peroxide vapour disinfection

    NARCIS (Netherlands)

    Tuladhar, E.; Terpstra, P.; Koopmans, M.; Duizer, E.

    2012-01-01

    Background: Viral contamination of surfaces is thought to be important in transmission. Chemical disinfection can be an effective means of intervention, but little is known about the virucidal efficacy of hydrogen peroxide vapour (HPV) against enteric and respiratory viruses. Aim: To measure the

  4. A novel OxyR sensor and regulator of hydrogen peroxide stress with one cysteine residue in Deinococcus radiodurans.

    Directory of Open Access Journals (Sweden)

    Huan Chen

    Full Text Available In bacteria, OxyR is a peroxide sensor and transcription regulator, which can sense the presence of reactive oxygen species and induce antioxidant system. When the cells are exposed to H(2O(2, OxyR protein is activated via the formation of a disulfide bond between the two conserved cysteine residues (C199 and C208. In Deinococcus radiodurans, a previously unreported special characteristic of DrOxyR (DR0615 is found with only one conserved cysteine. dr0615 gene mutant is hypersensitive to H(2O(2, but only a little to ionizing radiation. Site-directed mutagenesis and subsequent in vivo functional analyses revealed that the conserved cysteine (C210 is necessary for sensing H(2O(2, but its mutation did not alter the binding characteristics of OxyR on DNA. Under oxidant stress, DrOxyR is oxidized to sulfenic acid form, which can be reduced by reducing reagents. In addition, quantitative real-time PCR and global transcription profile results showed that OxyR is not only a transcriptional activator (e.g., katE, drb0125, but also a transcriptional repressor (e.g., dps, mntH. Because OxyR regulates Mn and Fe ion transporter genes, Mn/Fe ion ratio is changed in dr0615 mutant, suggesting that the genes involved in Mn/Fe ion homeostasis, and the genes involved in antioxidant mechanism are highly cooperative under extremely oxidant stress. In conclusion, these findings expand the OxyR family, which could be divided into two classes: typical 2-Cys OxyR and 1-Cys OxyR.

  5. 21 CFR 178.1005 - Hydrogen peroxide solution.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Hydrogen peroxide solution. 178.1005 Section 178... SANITIZERS Substances Utilized To Control the Growth of Microorganisms § 178.1005 Hydrogen peroxide solution. Hydrogen peroxide solution identified in this section may be safely used to sterilize polymeric food...

  6. Hydrogen peroxide decomposition kinetics in aquaculture water

    DEFF Research Database (Denmark)

    Arvin, Erik; Pedersen, Lars-Flemming

    2015-01-01

    Hydrogen peroxide (HP) is used in aquaculture systems where preventive or curative water treatments occasionally are required. Use of chemical agents can be challenging in recirculating aquaculture systems (RAS) due to extended water retention time and because the agents must not damage the fish ...... in RAS by addressing disinfection demand and identify efficient and safe water treatment routines.......Hydrogen peroxide (HP) is used in aquaculture systems where preventive or curative water treatments occasionally are required. Use of chemical agents can be challenging in recirculating aquaculture systems (RAS) due to extended water retention time and because the agents must not damage the fish...... reared or the nitrifying bacteria in the biofilters at concentrations required to eliminating pathogens. This calls for quantitative insight into the fate of the disinfectant residuals during water treatment. This paper presents a kinetic model that describes the HP decomposition in aquaculture water...

  7. Functionalized Palladium Nanoparticles for Hydrogen Peroxide Biosensor

    Directory of Open Access Journals (Sweden)

    H. Baccar

    2011-01-01

    Full Text Available We present a comparison between two biosensors for hydrogen peroxide (H2O2 detection. The first biosensor was developed by the immobilization of Horseradish Peroxidase (HRP enzyme on thiol-modified gold electrode. The second biosensor was developed by the immobilization of cysteamine functionalizing palladium nanoparticles on modified gold surface. The amino groups can be activated with glutaraldehyde for horseradish peroxidase immobilization. The detection of hydrogen peroxide was successfully observed in PBS for both biosensors using the cyclic voltammetry and the chronoamperometry techniques. The results show that the limit detection depends on the large surface-to-volume ratio attained with palladium nanoparticles. The second biosensor presents a better detection limit of 7.5 μM in comparison with the first one which is equal to 75 μM.

  8. Mesenchymal stem cell conditioned medium alleviates oxidative stress injury induced by hydrogen peroxide via regulating miR143 and its target protein in hepatocytes.

    Science.gov (United States)

    Xu, Xuejing; Li, Dong; Li, Xue; Shi, Qing; Ju, Xiuli

    2017-12-19

    To investigate the impact of miRNA (microRNA) on hepatic oxidative stress damage under the human mesenchymal stem cell conditioned medium (MSC-CM) and explore the roles of the beta-1 adrenergic receptor (ADRB1) and hexokinase 2 (HK2) in this process. Hydrogen peroxide was used to induce oxidative stress injury in the human normal liver cell line L02. MSC-CM was separately prepared. After treatment with MSC-CM, the protective effects of MSC-CM on oxidative stress injury were assessed by changes in apoptosis, cell viability, cell cycle, and mitochondrial membrane potential. According to the microarray analysis, 19 disparately expressed miRNAs were selected for RT-PCR and miR143 identified as having significant differential expression in MSC-CM against oxidative stress injury. Subsequently, the predicted target proteins of miR143 were selected by bioinformatics software, and verified by western blot. In addition, down-regulation and up-regulation of miR143 expression and hydrogen peroxide induced hypoxia injury were carried out on L02 cells to study the role of miR143. MSC-CM significantly attenuated H 2 O 2 induced oxidative stress injury. The expression of miR143 was increased following oxidative stress injury whereas it decreased after MSC-CM treatment. The expression levels of HK2 and ADRB1 regulated by miR143 and Bcl-2 decreased under H 2 O 2 treatment but were restored following MSC-CM treatment. However the expression levels of Bax and BMF increased after H 2 O 2 injury and decreased after MSC-CM treatment. Moreover over-expression or down-regulation of miR143 aggravated or alleviated hepatocyte apoptosis respectively. MSC-CM may alleviate H 2 O 2 induced oxidative stress injury by inhibiting apoptosis and adjusting miRNA expression. Moreover down-regulation of miR143 protects L02 cells from apoptosis and initiates an adaptive process by adjusting the expression of HK2 ADRB1 and apoptosis-related proteins.

  9. Low Temperature-Induced 30 (LTI30 positively regulates drought stress resistance in Arabidopsis: effect on abscisic acid sensitivity and hydrogen peroxide accumulation

    Directory of Open Access Journals (Sweden)

    Haitao eShi

    2015-10-01

    Full Text Available As a dehydrin belonging to group II late embryogenesis abundant protein (LEA family, Arabidopsis Low Temperature-Induced 30 (LTI30/XERO2 has been shown to be involved in plant freezing stress resistance. However, the other roles of AtLTI30 remain unknown. In this study, we found that the expression of AtLTI30 was largely induced by drought stress and abscisic acid (ABA treatments. Thereafter, AtLTI30 knockout mutants and overexpressing plants were isolated to investigate the possible involvement of AtLTI30 in ABA and drought stress responses. AtLTI30 knockout mutants were less sensitive to ABA-mediated seed germination, while AtLTI30 overexpressing plants were more sensitive to ABA compared with wild type (WT. Consistently, the AtLTI30 knockout mutants displayed decreased drought stress resistance, while the AtLTI30 overexpressing plants showed improved drought stress resistance compared with WT, as evidenced by a higher survival rate and lower leaf water loss than WT after drought stress. Moreover, manipulation of AtLTI30 expression positively regulated the activities of catalases (CATs and endogenous proline content, as a result, negatively regulated drought stress-triggered hydrogen peroxide (H2O2 accumulation. All these results indicate that AtLTI30 is a positive regulator of plant drought stress resistance, partially through the modulation of ABA sensitivity, H2O2 and proline accumulation.

  10. [The origin of hydrogen peroxide in oral cavity and its role in oral microecology balance].

    Science.gov (United States)

    Keke, Zhang; Xuedong, Zhou; Xin, Xu

    2017-04-01

    Hydrogen peroxide, an important antimicrobial agent in oral cavity, plays a significant role in the balance of oral microecology. At the early stage of biofilm formation, about 80% of the detected initial colonizers belong to the genus Streptococcus. These oral streptococci use different oxidase to produce hydrogen peroxide. Recent studies showed that the produced hydrogen peroxide plays a critical role in modulating oral microecology. Hydrogen peroxide modulates biofilm development attributed to its growth inhibitory nature. Hydrogen peroxide production is closely associated with extracellular DNA(eDNA) release from microbe and the development of its competent cell which are critical for biofilm development and also serves as source for horizontal gene transfer. Microbe also can reduce the damage to themselves through several detoxification mechanisms. Moreover, hydrogen peroxide is also involved in the regulation of interactions between oral microorganisms and host. Taken together, hydrogen peroxide is an imperative ecological factor that contributes to the microbial equilibrium in the oral cavity. Here we will give a brief review of both the origin and the function in the oral microecology balance of hydrogen peroxide.

  11. Novel roles of hydrogen peroxide (H₂O₂) in regulating pectin synthesis and demethylesterification in the cell wall of rice (Oryza sativa) root tips.

    Science.gov (United States)

    Xiong, Jie; Yang, Yongjie; Fu, Guanfu; Tao, Longxing

    2015-04-01

    Hydrogen peroxide (H₂O₂) has been reported to increase lignin formation, enhance cell wall rigidification, restrict cell expansion and inhibit root elongation. However, our results showed that it not only inhibited rice (Oryza sativa) root elongation, but also increased root diameter. No study has reported how and why H₂O₂ increases cell expansion and root diameter. Exogenous H₂O₂ and its scavenger 4-hydroxy-Tempo were applied to confirm the roles of H₂O₂. Immunofluorescence, fluorescence probe, ruthenium red staining, histological section and spectrophotometry were used to monitor changes in the degree of pectin methylesterification, pectin content, pectin methylesterase (PME) activity and H₂O₂ content. Exogenous H₂O₂ inhibited root elongation, but increased cell expansion and root diameter significantly. H₂O₂ not only increased the region of pectin synthesis and pectin content in root tips, but also increased PME activity and pectin demethylesterification. The scavenger 4-hydroxy-Tempo reduced root H₂O₂ content and recovered H₂O₂-induced increases in cell expansion and root diameter by inhibiting pectin synthesis, PME activity and pectin demethylesterification. H₂O₂ plays a novel role in the regulation of pectin synthesis, PME activity and pectin demethylesterification. H₂O₂ increases cell expansion and root diameter by increasing pectin content and demethylesterification. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  12. Use of Hydrogen Peroxide to Disinfect Hydroponic Plant Growth Systems

    Science.gov (United States)

    Barta, Daniel J.; Henderson, Keith

    2000-01-01

    Hydrogen peroxide was studied as an alternative to conventional bleach and rinsing methods to disinfect hydroponic plant growth systems. A concentration of 0.5% hydrogen peroxide was found to be effective. Residual hydrogen peroxide can be removed from the system by repeated rinsing or by flowing the solution through a platinum on aluminum catalyst. Microbial populations were reduced to near zero immediately after treatment but returned to pre-disinfection levels 2 days after treatment. Treating nutrient solution with hydrogen peroxide and planting directly into trays being watered with the nutrient solution without replenishment, was found to be detrimental to lettuce germination and growth.

  13. Hydrogen peroxide probes directed to different cellular compartments.

    Directory of Open Access Journals (Sweden)

    Mikalai Malinouski

    2011-01-01

    Full Text Available Controlled generation and removal of hydrogen peroxide play important roles in cellular redox homeostasis and signaling. We used a hydrogen peroxide biosensor HyPer, targeted to different compartments, to examine these processes in mammalian cells.Reversible responses were observed to various redox perturbations and signaling events. HyPer expressed in HEK 293 cells was found to sense low micromolar levels of hydrogen peroxide. When targeted to various cellular compartments, HyPer occurred in the reduced state in the nucleus, cytosol, peroxisomes, mitochondrial intermembrane space and mitochondrial matrix, but low levels of the oxidized form of the biosensor were also observed in each of these compartments, consistent with a low peroxide tone in mammalian cells. In contrast, HyPer was mostly oxidized in the endoplasmic reticulum. Using this system, we characterized control of hydrogen peroxide in various cell systems, such as cells deficient in thioredoxin reductase, sulfhydryl oxidases or subjected to selenium deficiency. Generation of hydrogen peroxide could also be monitored in various compartments following signaling events.We found that HyPer can be used as a valuable tool to monitor hydrogen peroxide generated in different cellular compartments. The data also show that hydrogen peroxide generated in one compartment could translocate to other compartments. Our data provide information on compartmentalization, dynamics and homeostatic control of hydrogen peroxide in mammalian cells.

  14. Brown Adipose Tissue Regulates Small Artery Function Through NADPH Oxidase 4-Derived Hydrogen Peroxide and Redox-Sensitive Protein Kinase G-1α.

    Science.gov (United States)

    Friederich-Persson, Malou; Nguyen Dinh Cat, Aurelie; Persson, Patrik; Montezano, Augusto C; Touyz, Rhian M

    2017-03-01

    Biomedical interest in brown adipose tissue (BAT) has increased since the discovery of functionally active BAT in adult humans. Although white adipose tissue (WAT) influences vascular function, vascular effects of BAT are elusive. Thus, we investigated the regulatory role and putative vasoprotective effects of BAT, focusing on hydrogen peroxide, nicotinamide adenine dinucleotide phosphate oxidase 4 (Nox4), and redox-sensitive signaling. Vascular reactivity was assessed in wild-type and Nox4-knockout mice (Nox4(-/-)) by wire myography in the absence and presence of perivascular adipose tissue of different phenotypes from various adipose depots: (1) mixed WAT/BAT (inguinal adipose tissue) and (2) WAT (epididymal visceral fat) and BAT (intrascapular fat). In wild-type mice, epididymal visceral fat and perivascular adipose tissue increased EC50 to noradrenaline without affecting maximum contraction. BAT increased EC50 and significantly decreased maximum contraction, which were prevented by a hydrogen peroxide scavenger (polyethylene glycated catalase) and a specific cyclic GMP-dependent protein kinase G type-1α inhibitor (DT-3), but not by inhibition of endothelial nitric oxide synthase or guanylate cyclase. BAT induced dimerization of cyclic GMP-dependent protein kinase G type-1α and reduced phosphorylation of myosin light chain phosphatase subunit 1 and myosin light chain 20. BAT from Nox4-knockout mice displayed reduced hydrogen peroxide levels and no anticontractile effects. Perivascular adipose tissue from β3 agonist-treated mice displayed browned perivascular adipose tissue and an increased anticontractile effect. We identify a novel vasoprotective action of BAT through an anticontractile effect that is mechanistically different to WAT. Specifically, BAT, via Nox4-derived hydrogen peroxide, induces cyclic GMP-dependent protein kinase G type-1α activation, resulting in reduced vascular contractility. BAT may constitute an interesting therapeutic target to

  15. Switching off hydrogen peroxide hydrogenation in the direct synthesis process.

    Science.gov (United States)

    Edwards, Jennifer K; Solsona, Benjamin; N, Edwin Ntainjua; Carley, Albert F; Herzing, Andrew A; Kiely, Christopher J; Hutchings, Graham J

    2009-02-20

    Hydrogen peroxide (H2O2) is an important disinfectant and bleach and is currently manufactured from an indirect process involving sequential hydrogenation/oxidation of anthaquinones. However, a direct process in which H2 and O2 are reacted would be preferable. Unfortunately, catalysts for the direct synthesis of H2O2 are also effective for its subsequent decomposition, and this has limited their development. We show that acid pretreatment of a carbon support for gold-palladium alloy catalysts switches off the decomposition of H2O2. This treatment decreases the size of the alloy nanoparticles, and these smaller nanoparticles presumably decorate and inhibit the sites for the decomposition reaction. Hence, when used in the direct synthesis of H2O2, the acid-pretreated catalysts give high yields of H2O2 with hydrogen selectivities greater than 95%.

  16. OxyR-regulated catalase CatB promotes the virulence in rice via detoxifying hydrogen peroxide in Xanthomonas oryzae pv. oryzae.

    Science.gov (United States)

    Yu, Chao; Wang, Nu; Wu, Maosen; Tian, Fang; Chen, Huamin; Yang, Fenghuan; Yuan, Xiaochen; Yang, Ching-Hong; He, Chenyang

    2016-11-08

    To facilitate infection, Xanthomonas oryzae pv. oryzae (Xoo), the bacterial blight pathogen of rice, needs to degrade hydrogen peroxide (H2O2) generated by the host defense response via a mechanism that is mediated by the transcriptional regulator OxyR. The catalase (CAT) gene catB has previously been shown to belong to the OxyR regulon in Xoo. However, its expression patterns and function in H2O2 detoxification and bacterial pathogenicity on rice remain to be elucidated. The catB gene encodes a putative catalase and is highly conserved in the sequenced strains of Xanthomonas spp. β-galactosidase analysis and electrophoretic mobility shift assays (EMSA) showed that OxyR positively regulated the transcription of catB by directly binding to its promoter region. The quantitative real-time PCR (qRT-PCR) assays revealed that the expression levels of catB and oxyR were significantly induced by H2O2. Deletion of catB or oxyR drastically impaired bacterial viability in the presence of extracellular H2O2 and reduced CAT activity, demonstrating that CatB and OxyR contribute to H2O2 detoxification in Xoo. In addition, ΔcatB and ΔoxyR displayed shorter bacterial blight lesions and reduced bacterial growth in rice compared to the wild-type stain, indicating that CatB and OxyR play essential roles in the virulence of Xoo. Transcription of catB is enhanced by OxyR in response to exogenous H2O2. CatB functions as an active catalase that is required for the full virulence of Xoo in rice.

  17. Salidroside protects against hydrogen peroxide-induced injury in HUVECs via the regulation of REDD1 and mTOR activation.

    Science.gov (United States)

    Xu, Mao-Chun; Shi, Hai-Ming; Wang, Hao; Gao, Xiu-Fang

    2013-07-01

    Antioxidative therapy is considered an effective strategy for treating oxidative stress-induced apoptosis in cardiovascular diseases. Salidroside has been used as an antioxidative therapy for oxidative injury in cardiac diseases. However, the mechanism underlying its antioxidant effect is poorly understood. The present study aimed to investigate the pharmacological effects of salidroside on cultured human umbilical vein endothelial cells (HUVECs) under conditions of oxidative injury induced by hydrogen peroxide (H2O2) and the underlying mechanisms in vitro. HUVECs pretreated with or without salidroside for 24 h were exposed to H2O2-induced oxidative stress conditions for 6 h and then cell viability, apoptosis, HIF-1α, regulated in development and DNA damage responses-1 (REDD1) and the PI3K/Akt/mTOR pathway were investigated. The results demonstrated that salidroside effectively attenuated H2O2-impaired cell viability and the production of reactive oxygen species (ROS) in a concentration-dependent manner. Reduced H2O2-induced apoptosis and activation of the cellular PI3K/Akt/mTOR pathway were demonstrated in HUVECs pretreated with salidroside. Furthermore, the level of REDD1, a direct regulator of mitochondrial metabolism, significantly increased in parallel with the level of HIF-1α following pretreatment with salidroside. The antioxidative effect of salidroside was abrogated in REDD1 knockdown cells. However, LY294002, a PI3K inhibitor, attenuated the anti-apoptotic effect of salidroside and blocked the increase of Akt and mTOR; however, did not affect the antioxidative effect of salidroside. These findings suggested that salidroside was capable of protecting HUVECs against H2O2-induced apoptosis by activating the PI3K/Akt/mTOR-dependent pathway and inhibiting ROS production by activating REDD1.

  18. A hydrogen peroxide sensor for exhaled breath measurement

    NARCIS (Netherlands)

    Dam, T.V.A.; Olthuis, Wouter; Bergveld, Piet; van den Berg, Albert

    2004-01-01

    An increase in produced hydrogen peroxide concentration in exhaled breath (EB) of patients, who suffer from some diseases related to lung function, has been observed and considered as a reliable indicator of lung diseases. In the EB of these patients, hydrogen peroxide is present in the vapour phase

  19. A hydrogen peroxide sensor for exhaled breath measurement

    NARCIS (Netherlands)

    Dam, T.V.A.; Olthuis, Wouter; Bergveld, Piet

    2005-01-01

    An increase in hydrogen peroxide concentration in exhaled breath (EB) of patients, who suffer from some diseases related to the lung function, has been observed and considered as a reliable indicator of lung diseases. In the EB of these patients, hydrogen peroxide is present in the vapour phase

  20. Preliminary note on the utitization of alkaline hydrogen peroxide ...

    African Journals Online (AJOL)

    The effect of alkaline hydrogen peroxide (AHp) treatment and urea supplementation on the feeding value of wheat straw was investigated in a 2x2 factorial experiment with sheep. Bales of wheat straw were dipped for a period of 24 h in an. AHP solution consisting of 1"/" hydrogen peroxide and 0,55% sodium hydroxide ...

  1. The evaluation of hydrogen peroxide bleaching of Gonometa ...

    African Journals Online (AJOL)

    The effect of hydrogen peroxide bleaching on Gonometa postica silk and the influence that temperature, pH and time duration had on hydrogen peroxide release , colour change, breaking load and stiffness were determined. The best bleaching (81 delta E) of the Gonometa postica silk fabric was obtained with 60 minutes ...

  2. Ultrafast shock induced chemistry in hydrogen peroxide

    Science.gov (United States)

    Armstrong, Michael; Zaug, Joseph; Goldman, Nir; Kuo, I.-Feng; Crowhurst, Jonathan; Howard, W. Michael; Carter, Jeffrey; Kashgarian, Michaele; Chesser, John; Barbee, Troy; Bastea, Sorin

    2013-03-01

    Although strong compression waves have been used to study the equilibrium high pressure and temperature properties of materials for more than half a century, the study of ultrafast strain rate dependent material transformations, while promising, is only beginning to be fully explored. Shock waves can change the thermodynamic state of a material over a picosecond time scale, i.e. faster than the time scale of quasi-equilibrium reaction kinetics for many reactive systems. This fundamental property of shock compression suggests the possibility of selecting reaction paths via modulation of applied compression waves on a time scale that is faster than the time scale of reaction kinetics. Here we present experiments and thermochemical and molecular dynamics simulations on a model system, hydrogen peroxide, which demonstrate that the applied strain rate can be used alongside the pressure and temperature to control reactivity in bulk matter, thus enabling the exploration of otherwise inaccessible chemical reaction paths.

  3. Hydrogen and oxygen isotope values in hydrogen peroxide.

    Science.gov (United States)

    Barnette, Janet E; Lott, Michael J; Howa, John D; Podlesak, David W; Ehleringer, James R

    2011-05-30

    Hydrogen peroxide (H(2)O(2)) is a widely used oxidizer with many commercial applications; unfortunately, it also has terrorist-related uses. We analyzed 97 hydrogen peroxide solutions representing four grades purchased across the United States and in Mexico. As expected, the range of hydrogen (δ(2)H, 230‰) and oxygen (δ(18)O, 24‰) isotope values of the H(2)O(2) solutions was large, reflecting the broad isotopic range of dilution waters. This resulted in predictable linear relationships of δ(2)H and δ(18)O values of H(2)O(2) solutions that were near parallel to the Meteoric Water Line (MWL), offset by the concentration of H(2)O(2) in the solution. By grade, dilute (3 to 35%) H(2)O(2) solutions were not statistically different in slope. Although the δ(2)H values of manufactured H(2)O(2) could be different from those of water, rapid H(2)O(2)-H(2)O exchange of H atoms eliminated any distinct isotope signal. We developed a method to measure the δ(18)O value of H(2)O(2) independent of dilution water by directly measuring O(2) gas generated from a catalase-induced disproportionation reaction. We predicted that the δ(18)O values of H(2)O(2) would be similar to that of atmospheric oxygen (+23.5‰), the predominant source of oxygen in the most common H(2)O(2) manufacturing process (median disproportionated δ(18)O=23.8‰). The predictable H-O relationships in H(2)O(2) solutions make it possible to distinguish commercial dilutions from clandestine concentration practices. Future applications of this work include synthesis studies that investigate the chemical link between H(2)O(2) reagents and peroxide-based explosive products, which may assist law enforcement in criminal investigations. Copyright © 2011 John Wiley & Sons, Ltd.

  4. Unusual hydrogen peroxide decomposition on stoichiometric insulating oxide ultrathin films

    CERN Document Server

    Song, Zhenjun

    2016-01-01

    The hydrogen peroxide dissociation on MgO(001) films deposited on Mo(001) surface is investigated by employing periodic density-functional theory methods. The pristine MgO(001) surface showing chemical inertness prefers the weak adsorbing molecular configuration and is extremely difficult to react with hydrogen peroxide. As far as we know, energetically favorable decomposition state of hydrogen peroxide has never been obtained on MgO(001) surface. In this work the hydrogen peroxide is successfully dissociated on perfect stoichiometric MgO(001) films by depositing on transition metal substrate, without any activation barrier. The spontaneous dissociation of hydrogen peroxide on metal supported oxide films is rationalized by characterizing the geometric structures and electronic structures.

  5. Down-regulation of catalase activity allows transient accumulation of a hydrogen peroxide signal in Chlamydomonas reinhardtii.

    Science.gov (United States)

    Michelet, Laure; Roach, Thomas; Fischer, Beat B; Bedhomme, Mariette; Lemaire, Stéphane D; Krieger-Liszkay, Anja

    2013-06-01

    In photosynthetic organisms, excess light is a stress that induces production of reactive oxygen species inside the chloroplasts. As a response, the capacity of antioxidative defence mechanisms increases. However, when cells of Chlamydomonas reinhardtii were shifted from dark to high light, a reversible partial inactivation of catalase activity was observed, which correlated with a transient increase in the level of H2 O2 in the 10 μm range. This concentration range seems to be necessary to activate H2 O2 -dependent signalling pathways stimulating the expression of H2 O2 responsive genes, such as the heat shock protein HSP22C. Catalase knock-down mutants had lost the transient accumulation of H2 O2 , suggesting that a decrease in catalase activity was the key element for establishing a transient H2 O2 burst. Catalase was inactivated by a one-electron event consistent with the reduction of a single cysteine. We propose that under high light intensity, the redox state of the photosynthetic electron transport chain is sensed and transmitted to the cytosol to regulate the catalase activity. This allows a transient accumulation of H2 O2 , inducing a signalling event that is transmitted to the nucleus to modulate the expression of chloroplast-directed protection enzymes. © 2012 Blackwell Publishing Ltd.

  6. RosR (Cg1324), a hydrogen peroxide-sensitive MarR-type transcriptional regulator of Corynebacterium glutamicum.

    Science.gov (United States)

    Bussmann, Michael; Baumgart, Meike; Bott, Michael

    2010-09-17

    The cg1324 gene (rosR) of Corynebacterium glutamicum encodes a MarR-type transcriptional regulator. By a comparative transcriptome analysis with DNA microarrays of a ΔrosR mutant and the wild type and subsequent EMSAs with purified RosR protein, direct target genes of RosR were identified. The narKGHJI operon, which encodes a nitrate/nitrite transporter and the dissimilatory nitrate reductase complex, was activated by RosR. All other target genes were repressed by RosR. They encode four putative monooxygenases, two putative FMN reductases, a protein of the glutathione S-transferase family, a putative polyisoprenoid-binding protein, and RosR itself. The DNA binding site of RosR was characterized as an 18-bp inverted repeat with the consensus sequence TTGTTGAYRYRTCAACWA. The in vitro DNA binding activity of RosR was reversibly inhibited by the oxidant H(2)O(2). Mutational analysis of the three cysteine residues present in RosR (Cys-64, Cys-92, and Cys-151) showed that these are responsible for the inhibition of DNA binding by H(2)O(2). A deletion mutant (Δcg1322) lacking the putative polyisoprenoid-binding protein showed an increased sensitivity to H(2)O(2), supporting the role of RosR in the oxidative stress response of C. glutamicum.

  7. Myocyte Enhancer Factor 2A Regulates Hydrogen Peroxide-Induced Senescence of Vascular Smooth Muscle Cells Via microRNA-143.

    Science.gov (United States)

    Zhao, Wang; Zheng, Xi-Long; Peng, Dao-Quan; Zhao, Shui-Ping

    2015-09-01

    Myocyte enhancer factor 2A (MEF2A) is involved in vascular smooth muscle cell (VSMC) proliferation, migration, and senescence. MicroRNA-143/145 (miR-143/145), which may be regulated by MEF2A, is known to promote cellular senescence. We hypothesized that MEF2A may promote VSMC senescence via miR-143/145. VSMC senescence was induced by hydrogen peroxide (H(2)O(2)), followed by detection using a senescence-associated β-galactosidase staining kit. The MEF2A protein, mRNA, and miR-143/145 levels in VSMCs were detected using Western blot analysis and SYBR green real-time quantitative PCR, respectively. We further manipulated the expression levels of MEF2A and miR-143 through viral or transient transfection. VSMC proliferation and migration were determined by methylthiazolyldiphenyl-tetrazolium bromide and Millicell chamber, respectively. Both MEF2A and miR-143, but not miRNA-145, were up-regulated in senescent VSMCs. Overexpression of either MEF2A or miR-143 significantly enhanced VSMC senescence, but reduced proliferation and migration. MEF2A knockdown or miR-143 inhibitor suppressed cellular senescence and increased proliferation and migration. We further revealed AKT signaling as a potential miR-143 target, and an induction of miR-143 expression by MEF2A via KLF2. Additionally, overexpression of MEF2A and miR-143 resulted in synergistic effects on promotion of senescence, and MEF2A knockdown and miR-143 reduction by inhibitor had synergistic inhibitory effects. Finally, MEF2A barely promoted VSMC senescence when miR-143 was inhibited, and miR-143 overexpression antagonized the inhibitory effect of MEF2A knockdown on VSMC senescence. Our results revealed a link and interaction between MEF2A and miR-143 and suggested a potential mechanism for MEF2A to regulate H(2)O(2) -induced VSMC senescence. © 2015 Wiley Periodicals, Inc.

  8. Kinetics of Platinum-Catalyzed Decomposition of Hydrogen Peroxide

    Science.gov (United States)

    Vetter, Tiffany A.; Colombo, D. Philip, Jr.

    2003-07-01

    CIBA Vision Corporation markets a contact lens cleaning system that consists of an AOSEPT disinfectant solution and an AOSEPT lens cup. The disinfectant is a buffered 3.0% m/v hydrogen peroxide solution and the cup includes a platinum-coated AOSEPT disc. The hydrogen peroxide disinfects by killing bacteria, fungi, and viruses found on the contact lenses. Because the concentration of hydrogen peroxide needed to disinfect is irritating to eyes, the hydrogen peroxide needs to be neutralized, or decomposed, before the contact lenses can be used again. A general chemistry experiment is described where the kinetics of the catalyzed decomposition of the hydrogen peroxide are studied by measuring the amount of oxygen generated as a function of time. The order of the reaction with respect to the hydrogen peroxide, the rate constant, and the energy of activation are determined. The integrated rate law is used to determine the time required to decompose the hydrogen peroxide to a concentration that is safe for eyes.

  9. Hydrogen peroxide mechanosynthesis in siloxane-hydrogel contact lenses.

    Science.gov (United States)

    Tavazzi, Silvia; Ferraro, Lorenzo; Cozza, Federica; Pastori, Valentina; Lecchi, Marzia; Farris, Stefano; Borghesi, Alessandro

    2014-11-26

    Drug-loaded contact lenses are emerging as the preferred treatment method for several ocular diseases, and efforts are being directed to promote extended and controlled delivery. One strategy is based on delivery induced by environmental triggers. One of these triggers can be hydrogen peroxide, since many platforms based on drug-loaded nanoparticles were demonstrated to be hydrogen-peroxide responsive. This is particularly interesting when hydrogen peroxide is the result of a specific pathophysiological condition. Otherwise, an alternative route to induce drug delivery is here proposed, namely the mechano-synthesis. The present work represents the proof-of-concept of the mechanosynthesis of hydrogen peroxide in siloxane-hydrogel contact lenses as a consequence of the cleavage of siloxane bonds at the interface between the polymer and water in aqueous phase. Their spongy morphology makes contact lenses promising systems for mechanical-to-chemical energy conversion, since the amount of hydrogen peroxide is expected to scale with the interfacial area between the polymer and water. The eyelid pressure during wear is sufficient to induce the hydrogen peroxide synthesis with concentrations which are biocompatible and suitable to trigger the drug release through hydrogen-peroxide-responsive platforms. For possible delivery on demand, the integration of piezoelectric polymers in the siloxane-hydrogel contact lenses could be designed, whose mechanical deformation could be induced by an applied wireless-controlled voltage.

  10. Inactivation of rabies virus by hydrogen peroxide.

    Science.gov (United States)

    Abd-Elghaffar, Asmaa A; Ali, Amal E; Boseila, Abeer A; Amin, Magdy A

    2016-02-03

    Development of safe and protective vaccines against infectious pathogens remains a challenge. Inactivation of rabies virus is a critical step in the production of vaccines and other research reagents. Beta-propiolactone (βPL); the currently used inactivating agent for rabies virus is expensive and proved to be carcinogenic in animals. This study aimed to investigate the ability of hydrogen peroxide (H2O2) to irreversibly inactivate rabies virus without affecting its antigenicity and immunogenicity in pursuit of finding safe, effective and inexpensive alternative inactivating agents. H2O2 3% rapidly inactivated a Vero cell adapted fixed rabies virus strain designated as FRV/K within 2h of exposure without affecting its antigenicity or immunogenicity. No residual infectious virus was detected and the H2O2-inactivated vaccine proved to be safe and effective when compared with the same virus harvest inactivated with the classical inactivating agent βPL. Mice immunized with H2O2-inactivated rabies virus produced sufficient level of antibodies and were protected when challenged with lethal CVS virus. These findings reinforce the idea that H2O2 can replace βPL as inactivating agent for rabies virus to reduce time and cost of inactivation process. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Lab-scale hydrogen peroxide data from ECBC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Data from small lab scale tests conducted at ECBC. It contains efficacy data as well as data on env conditions such as temperature, RH, and hydrogen peroxide vapor...

  12. Mechanism of action of hydrogen peroxide in wheat thermotolerance

    African Journals Online (AJOL)

    Mechanism of action of hydrogen peroxide in wheat thermotolerance - interaction between antioxidant isoenzymes, proline and cell membrane. Ranjeet Ranjan Kumar, Sushil Kumar Sharma, Kritika A. Gadpayle, Khushboo Singh, R Sivaranjani, Suneha Goswami, D. Rai Raj ...

  13. Efficient Electrochemical Hydrogen Peroxide Generation in Water Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An electrochemical cell is proposed for the efficient generation of 3% hydrogen peroxide (H2O2) in pure water using only power, oxygen and water. H2O2 is an...

  14. Potentiometric Titration Method for Quantitative Determination of Hydrogen Peroxide

    National Research Council Canada - National Science Library

    Bessette, Russell R

    2005-01-01

    An electrochemical potentiometric titration method that entails titration of a known volume of a catholyte containing an unknown amount of hydrogen peroxide in a titration cell having two electrodes...

  15. Sodium Borohydride/Hydrogen Peroxide Fuel Cells For Space Application

    Science.gov (United States)

    Valdez, T. I.; Deelo, M. E.; Narayanan, S. R.

    2006-01-01

    This viewgraph presentation examines Sodium Borohydride and Hydrogen Peroxide Fuel Cells as they are applied to space applications. The topics include: 1) Motivation; 2) The Sodium Borohydride Fuel Cell; 3) Sodium Borohydride Fuel Cell Test Stands; 4) Fuel Cell Comparisons; 5) MEA Performance; 6) Anode Polarization; and 7) Electrode Analysis. The benefits of hydrogen peroxide as an oxidant and benefits of sodium borohydride as a fuel are also addressed.

  16. Physico Chemical Characteristic of Kappa Carrageenan Degraded Using Hydrogen Peroxide

    Directory of Open Access Journals (Sweden)

    Rizki Febriansyah Siregar

    2016-12-01

    Full Text Available Kappa carrageenan is polysaccharide that widely used in food, pharmaceutical, cosmetic, textile and printing industries as coagulate agent, stabilizer and gelling agent. Hydrogen peroxide (H2 O2 is strong oxidator to degrade polysaccharide. Hydrogen peroxide has some advantades such as cheap, easy to get and savety environment. Degradation method using hydrogen peroxide is a technology based on establishment radical hydoxile reactive that attack the glycosidic of polysaccharides as a result reducing in molecular weight of polysaccharide. The aims of this study were to analyze the effect of hydrogen peroxide concentration, temperature and degradation time to molecular weight of refined kappa carrageenan. Structural changes on kappa carrageenan degradation were characterized by viscometer, SEM and FTIR. Hydrogen peroxide concentration, temperature and degradation time were significantly reducing molecular weight and changes in the structural function of refined kappa carrageenan. The lowest molecular weight of refined kappa carrageenan degraded was obtained from the treatment 3% of hydrogen peroxide at temperature 80°C and degradation time for 4 hours.

  17. Physico Chemical Characteristic of Kappa Carrageenan Degraded Using Hydrogen Peroxide

    Directory of Open Access Journals (Sweden)

    Rizky Febriansyah Siregar

    2017-02-01

    Full Text Available AbstractKappa carrageenan is polysaccharide that widely used in food, pharmaceutical, cosmetic, textile and printing industries as coagulate agent, stabilizer and gelling agent. Hydrogen peroxide (H2O2 is strong oxidator to degrade polysaccharide. Hydrogen peroxide has some advantades such as cheap, easy to get and savety environment. Degradation method using hydrogen peroxide is a technology based on establishment radical hydoxile reactive that attack the glycosidic of polysaccharides as a result reducing in molecular weight of polysaccharide. The aims of this study were to analyze the effect of hydrogen peroxide concentration, temperature and degradation time to molecular weight of refined kappa carrageenan. Structural changes on kappa carrageenan degradation were characterized by viscometer, SEM and FTIR. Hydrogen peroxide concentration, temperature and degradation time were significantly reducing molecular weight and changes in the structural function of refined kappa carrageenan. The lowest molecular weight of refined kappa carrageenan degraded was obtained from the treatment 3% of hydrogen peroxide at temperature 80°C and degradation time for 4 hours.

  18. Localised hydrogen peroxide sensing for reproductive health

    Science.gov (United States)

    Purdey, Malcolm S.; Schartner, Erik P.; Sutton-McDowall, Melanie L.; Ritter, Lesley J.; Thompson, Jeremy G.; Monro, Tanya M.; Abell, Andrew D.

    2015-05-01

    The production of reactive oxygen species (ROS) is known to affect the developmental competence of embryos. Hydrogen peroxide (H2O2) an important reactive oxygen species, is also known to causes DNA damage and defective sperm function. Current techniques require incubating a developing embryo with an organic fluorophore which is potentially hazardous for the embryo. What we need is a localised ROS sensor which does not require fluorophores in solution and hence will allow continuous monitoring of H2O2 production without adversely affect the development of the embryo. Here we report studies on such a fibre-based sensor for the detection of H2O2 that uses a surface-bound aryl boronate fluorophore carboxyperoxyfluor-1(CPF1). Optical fibres present a unique platform due to desirable characteristics as dip sensors in biological solutions. Attempts to functionalise the fibre tips using polyelectrolyte layers and (3-aminopropyl)triethoxysilane (APTES) coatings resulted in a limited signal and poor fluorescent response to H2O2 due to a low tip surface density of the fluorophore. To increase the surface density, CPF1 was integrated into a polymer matrix formed on the fibre tip by a UV-catalysed polymerisation process of acrylamide onto a methacrylate silane layer. The polyacrylamide containing CPF1 gave a much higher surface density than previous surface attachment methods and the sensor was found to effectively detect H2O2. Using this method, biologically relevant concentrations of H2O2 were detected, enabling remote sensing studies into ROS releases from embryos throughout early development.

  19. Recent Development in Hydrogen Peroxide Pumped Propulsion

    Energy Technology Data Exchange (ETDEWEB)

    Ledebuhr, A G; Antelman, D R; Dobie, D W; Gorman, T S; Jones, M S; Kordas, J F; McMahon, D H; Ng, L C; Nielsen, D P; Ormsby, A E; Pittenger, L C; Robinson, J A; Skulina, K M; Taylor, W G; Urone, D A; Wilson, B A

    2004-03-22

    This paper describes the development of a lightweight high performance pump-fed divert and attitude control system (DACS). Increased kinetic Kill Vehicles (KV) capabilities (higher .v and acceleration capability) will especially be needed for boost phase engagements where a lower mass KV DACS enables smaller overall interceptors. To increase KV performance while reducing the total DACS dry mass (<10 kg), requires a design approach that more closely emulates those found in large launch vehicles, where pump-fed propulsion enables high propellant-mass-fraction systems. Miniaturized reciprocating pumps, on a scale compatible with KV applications, offer the potential of a lightweight DACS with both high {Delta}v and acceleration capability, while still enabling the rapid pulsing of the divert thrusters needed in the end-game fly-in. Pumped propulsion uses lightweight low-pressure propellant tanks, as the main vehicle structure and eliminates the need for high-pressure gas bottles, reducing mass and increasing the relative propellant load. Prior work used hydrazine and demonstrated a propellant mass fraction >0.8 and a vehicle propulsion dry mass of {approx}3 kg. Our current approach uses the non-toxic propellants 90% hydrogen peroxide and kerosene. This approach enables faster development at lower costs due to the ease of handling. In operational systems these non-toxic propellants can simplify the logistics for manned environments including shipboard applications. This DACS design configuration is expected to achieve sufficient mass flows to support divert thrusters in the 1200 N to 1330 N (270 lbf to 300 lbf) range. The DACS design incorporates two pairs of reciprocating differential piston pumps (oxidizer and fuel), a warm-gas drive system, compatible bi-propellant thrusters, lightweight valves, and lightweight low-pressure propellant tanks. This paper summarizes the current development status and plans.

  20. Virucidal efficacy of hydrogen peroxide vapour disinfection.

    Science.gov (United States)

    Tuladhar, E; Terpstra, P; Koopmans, M; Duizer, E

    2012-02-01

    Viral contamination of surfaces is thought to be important in transmission. Chemical disinfection can be an effective means of intervention, but little is known about the virucidal efficacy of hydrogen peroxide vapour (HPV) against enteric and respiratory viruses. To measure the virucidal efficacy of HPV against respiratory and enteric viruses on materials representing those found in institutions and homes. Poliovirus, human norovirus genogroup II.4 (GII.4), murine norovirus 1, rotavirus, adenovirus and influenza A (H1N1) virus dried on to stainless steel, framing panel and gauze carriers were exposed to HPV 127 ppm for 1h at room temperature in an isolator. Poliovirus was also exposed to HPV at different locations in a room. The virucidal effect was measured by comparing recoverable viral titres against unexposed controls. Polymerase chain reaction was used to evaluate the effect of HPV on viral genome reduction. HPV disinfection resulted in complete inactivation of all viruses tested, characterized by >4 log(10) reduction in infectious particles for poliovirus, rotavirus, adenovirus and murine norovirus on stainless steel and framing panel carriers, and >2 log(10) reduction for influenza A virus on stainless steel and framing panel carriers, and for all viruses on gauze carriers. Complete inactivation of poliovirus was demonstrated at several locations in the room. Reductions in viral genomes were minimal on framing panel and gauze carriers but significant on stainless steel carriers; human norovirus GII.4 genome was most resistant to HPV treatment. HPV could be an effective virucidal against enteric and respiratory viruses contaminating in-house environments. Copyright © 2011 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  1. OO bond homolysis in hydrogen peroxide.

    Science.gov (United States)

    Sandhiya, Lakshmanan; Zipse, Hendrik

    2017-09-30

    OO bond homolysis in hydrogen peroxide (H2 O2 ) has been studied using theoretical methods of four conceptually different types: hybrid DFT (B3LYP, M06-2X), double-hybrid DFT (B2-PLYP), coupled-cluster (CCSD(T)), and multiconfigurational (CASPT2). In addition, the effects of basis set size have also been analyzed. For all of these methods, the OO bond homolysis in hydrogen peroxide has been found to proceed through hydrogen bonded radical pair complexes. Reaction barriers for collapse of the radical pairs to hydrogen peroxide are minute, leading to an overall very flat potential energy surface. However, hydrogen bonding energies in the radical pair complex expressed as the energy difference to two separate hydroxyl radicals are sizeable and exceed 10 kJ/mol for all theoretical methods considered in this study. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  2. Synergy between sulforaphane and selenium in the up-regulation of thioredoxin reductase and protection against hydrogen peroxide-induced cell death in human hepatocytes.

    Science.gov (United States)

    Li, Dan; Wang, Wei; Shan, Yujuan; Barrera, Lawrence N; Howie, Alexander F; Beckett, Geoffrey J; Wu, Kun; Bao, Yongping

    2012-07-15

    Dietary isothiocyanates and selenium are chemopreventive agents and potent inducers of antioxidant enzymes. It has been previously shown that sulforaphane and selenium have a synergistic effect on the upregulation of thioredoxin reductase-1 (TrxR-1) in human hepatoma HepG2 cells. In this paper, further evidence is presented to show that sulforaphane and selenium synergistically induce TrxR-1 expression in immortalised human hepatocytes. Sulforaphane was found to be more toxic toward hepatocytes than HepG2 cells with IC50=25.1 and 56.4 μM, respectively. Sulforaphane can protect against hydrogen peroxide-induced cell death and this protection was enhanced by co-treatment with selenium. Using siRNA to knock down TrxR-1 or Nrf2, sulforaphane (5 μM)-protected cell viability was reduced from 73% to 46% and 34%, respectively, suggesting that TrxR-1 is an important enzyme in protection against hydrogen peroxide-induced cell death. Sulforaphane-induced TrxR-1 expression was positively associated with significant levels of Nrf2 translocation into the nucleus, but co-treatment with selenium showed no significant increase in Nrf2 translocation. Moreover, MAPK (ERK, JNK and p38) and PI3K/Akt signalling pathways were found to play no significant role in sulforaphane-induced Nrf2 translocation into the nucleus. However, blocking ERK and JNK signalling pathways decreased sulforaphane-induced TrxR-1 mRNA by about 20%; whereas blocking p38 and PI3K/AKT increased TrxR-1 transcription. In summary, a combination of sulforaphane and selenium resulted in a synergistic upregulation of TrxR-1 that contributed to the enhanced protection against free radical-mediated oxidative damage in human hepatocytes. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Can hydrogen peroxide and quercetin improve production of ...

    African Journals Online (AJOL)

    Vegetative propagation is considered the best choice for the rapid multiplication of plant species, however, rooting may still present difficulties. Substances, such as auxins, phenolic compounds and hydrogen peroxide, are recognized as able to improve this process. The aim of the present work was to determine if hydrogen ...

  4. Probing skin interaction with hydrogen peroxide using diffuse reflectance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zonios, George [Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina (Greece); Dimou, Aikaterini [Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina (Greece); Galaris, Dimitrios [Laboratory of Biological Chemistry, School of Medicine, University of Ioannina, 45110 Ioannina (Greece)

    2008-01-07

    Hydrogen peroxide is an important oxidizing agent in biological systems. In dermatology, it is frequently used as topical antiseptic, it has a haemostatic function, it can cause skin blanching, and it can facilitate skin tanning. In this work, we investigated skin interaction with hydrogen peroxide, non-invasively, using diffuse reflectance spectroscopy. We observed transient changes in the oxyhaemoglobin and deoxyhaemoglobin concentrations as a result of topical application of dilute H{sub 2}O{sub 2} solutions to the skin, with changes in deoxyhaemoglobin concentration being more pronounced. Furthermore, we did not observe any appreciable changes in melanin absorption properties as well as in the skin scattering properties. We also found no evidence for production of oxidized haemoglobin forms. Our observations are consistent with an at least partial decomposition of hydrogen peroxide within the stratum corneum and epidermis, with the resulting oxygen and/or remaining hydrogen peroxide inducing vasoconstriction to dermal blood vessels and increasing haemoglobin oxygen saturation. An assessment of the effects of topical application of hydrogen peroxide to the skin may serve as the basis for the development of non-invasive techniques to measure skin antioxidant capacity and also may shed light onto skin related disorders such as vitiligo.

  5. Functional analysis of a novel hydrogen peroxide resistance gene in Lactobacillus casei strain Shirota.

    Science.gov (United States)

    Serata, Masaki; Kiwaki, Mayumi; Iino, Tohru

    2016-11-01

    Lactic acid bacteria have a variety of mechanisms for tolerance to oxygen and reactive oxygen species, and these mechanisms differ among species. Lactobacillus casei strain Shirota grows well under aerobic conditions, indicating that the various systems involved in oxidative stress resistance function in this strain. To elucidate the mechanism of oxidative stress resistance in L. casei strain Shirota, we examined the transcriptome response to oxygen or hydrogen peroxide exposure. We then focused on an uncharacterized gene that was found to be up-regulated by both oxygen and hydrogen peroxide stress; we named the gene hprA1 (hydrogen peroxide resistance gene). This gene is widely distributed among lactobacilli. We investigated the involvement of this gene in oxidative stress resistance, as well as the mechanism of tolerance to hydrogen peroxide. Growth of L. casei MS105, an hprA1-disrupted mutant, was not affected by oxygen stress, whereas the survival rate of MS105 after hydrogen peroxide treatment was markedly reduced compared to that of the wild-type. However, the activity of MS105 in eliminating hydrogen peroxide was similar to that of the wild-type. We cloned hprA1 from L. caseiShirota and purified recombinant HprA1 protein from Escherichia coli. We demonstrated that the recombinant HprA1 protein bound to iron and prevented the formation of a hydroxyl radical in vitro. Thus, HprA1 protein probably contributes to hydrogen peroxide tolerance in L. casei strain Shirota by binding to iron in the cells and preventing the formation of a hydroxyl radical.

  6. Material Demand Studies: Materials Sorption of Vaporized Hydrogen Peroxide

    Science.gov (United States)

    2010-06-01

    agreement with the peroxide concentration from the iodometric titration was typically in error by approximately 15% due to the slight variation in...Verification of both sensors was conducted during each run. using the average value from three iodometric titrations on the VHP stream entering and exiting...The hydrogen peroxide sensor performance verification, using the wet- chemical titration method, showed that both the inlet and outlet sensors were

  7. Selective electrochemical generation of hydrogen peroxide from water oxidation

    CERN Document Server

    Viswanathan, Venkatasubramanian; Nørskov, Jens K

    2015-01-01

    Water is a life-giving source, fundamental to human existence, yet, over a billion people lack access to clean drinking water. Present techniques for water treatment such as piped, treated water rely on time and resource intensive centralized solutions. In this work, we propose a decentralized device concept that can utilize sunlight to split water into hydrogen and hydrogen peroxide. The hydrogen peroxide can oxidize organics while the hydrogen bubbles out. In enabling this device, we require an electrocatalyst that can oxidize water while suppressing the thermodynamically favored oxygen evolution and form hydrogen peroxide. Using density functional theory calculations, we show that the free energy of adsorbed OH$^*$ can be used as a descriptor to screen for selectivity trends between the 2e$^-$ water oxidation to H$_2$O$_2$ and the 4e$^-$ oxidation to O$_2$. We show that materials that bind oxygen intermediates sufficiently weakly, such as SnO$_2$, can activate hydrogen peroxide evolution. We present a rati...

  8. A MEMS methanol reformer heated by decomposition of hydrogen peroxide.

    Science.gov (United States)

    Kim, Taegyu; Hwang, Jin Soo; Kwon, Sejin

    2007-07-01

    This paper presents the design, fabrication and evaluation of a micro methanol reformer complete with a heat source. The micro system consists of the steam reforming reactor of methanol, the catalytic decomposition reactor of hydrogen peroxide, and a heat exchanger between the two reactors. In the present study, catalytic decomposition of hydrogen peroxide is used as a process to supply heat to the reforming reactor. The decomposition process of hydrogen peroxide produces water vapor and oxygen as a product that can be used efficiently to operate the reformer/PEMFC system. Cu/ZnO was selected as a catalyst for methanol steam reforming and Pt for the decomposition of hydrogen peroxide. Incipient wetness method was used to load catalysts on a porous support. Catalyst loaded supports were inserted in the cavity made on the glass wafer. The performance of the methanol steam reforming system was measured at various test conditions and the optimum operation condition was sought. At the optimum condition, the hydrogen selectivity was 86.4% and the thermal efficiency was 44.8%. The product gas included 74.1% H(2), 24.5% CO(2) and 1.4% CO and the total volume production rate was 23.5 ml min(-1). This amount of hydrogen can produce 1.5 W of power on a typical PEMFC.

  9. Hydrogen peroxide, signaling in disguise during metal phytotoxicity

    Directory of Open Access Journals (Sweden)

    Ann eCuypers

    2016-04-01

    Full Text Available Plants exposed to excess metals are challenged by an increased generation of reactive oxygen species (ROS such as superoxide (O2•-, hydrogen peroxide (H2O2 and the hydroxyl radical (•OH. The mechanisms underlying this oxidative challenge are often dependent on metal-specific properties and might play a role in stress perception, signaling and acclimation. Although ROS were initially considered as toxic compounds causing damage to various cellular structures, their role as signaling molecules became a topic of intense research over the last decade. Hydrogen peroxide in particular is important in signaling because of its relatively low toxicity, long lifespan and its ability to cross cellular membranes. The delicate balance between its production and scavenging by a plethora of enzymatic and metabolic antioxidants is crucial in the onset of diverse signaling cascades that finally lead to plant acclimation to metal stress. In this review, our current knowledge on the dual role of ROS in metal-exposed plants is presented. Evidence for a relationship between H2O2 and plant metal tolerance is provided. Furthermore, emphasis is put on recent advances in understanding cellular damage and downstream signaling responses as a result of metal-induced H2O2 production. Finally, special attention is paid to the interaction between H2O2 and other signaling components such as transcription factors, mitogen-activated protein kinases, phytohormones and regulating systems (e.g. microRNAs. These responses potentially underlie metal-induced senescence in plants. Elucidating the signaling network activated during metal stress is a pivotal step to make progress in applied technologies like phytoremediation of polluted soils.

  10. Hydrogen Peroxide, Signaling in Disguise during Metal Phytotoxicity

    Science.gov (United States)

    Cuypers, Ann; Hendrix, Sophie; Amaral dos Reis, Rafaela; De Smet, Stefanie; Deckers, Jana; Gielen, Heidi; Jozefczak, Marijke; Loix, Christophe; Vercampt, Hanne; Vangronsveld, Jaco; Keunen, Els

    2016-01-01

    Plants exposed to excess metals are challenged by an increased generation of reactive oxygen species (ROS) such as superoxide (O2•-), hydrogen peroxide (H2O2) and the hydroxyl radical (•OH). The mechanisms underlying this oxidative challenge are often dependent on metal-specific properties and might play a role in stress perception, signaling and acclimation. Although ROS were initially considered as toxic compounds causing damage to various cellular structures, their role as signaling molecules became a topic of intense research over the last decade. Hydrogen peroxide in particular is important in signaling because of its relatively low toxicity, long lifespan and its ability to cross cellular membranes. The delicate balance between its production and scavenging by a plethora of enzymatic and metabolic antioxidants is crucial in the onset of diverse signaling cascades that finally lead to plant acclimation to metal stress. In this review, our current knowledge on the dual role of ROS in metal-exposed plants is presented. Evidence for a relationship between H2O2 and plant metal tolerance is provided. Furthermore, emphasis is put on recent advances in understanding cellular damage and downstream signaling responses as a result of metal-induced H2O2 production. Finally, special attention is paid to the interaction between H2O2 and other signaling components such as transcription factors, mitogen-activated protein kinases, phytohormones and regulating systems (e.g. microRNAs). These responses potentially underlie metal-induced senescence in plants. Elucidating the signaling network activated during metal stress is a pivotal step to make progress in applied technologies like phytoremediation of polluted soils. PMID:27199999

  11. Remediation of sulfidic wastewater by catalytic oxidation with hydrogen peroxide.

    Science.gov (United States)

    Ahmad, Naveed; Maitra, Saikat; Dutta, Binay Kanti; Ahmad, Farooq

    2009-01-01

    Oxidation of sulfide in aqueous solution by hydrogen peroxide was investigated in the presence of hydrated ferric oxide catalyst. The ferric oxide catalyst was synthesized by sol gel technique from ferric chloride and ammonia. The synthesized catalyst was characterized by Fourier transform infrared spectroscopy, X-Ray diffraction analysis, scanning electrom microscope and energy dispersive X-ray analysis. The catalyst was quite effective in oxidizing the sulfide by hydrogen peroxide. The effects of sulfide concentration, catalyst loading, H2O2 dosing and temperature on the kinetics of sulfide oxidation were investigated. Kinetic equations and activation energies for the catalytic oxidation reaction were calculated based on the experimental results.

  12. Hydrogen Peroxide Gas Generator Cycle with a Reciprocating Pump

    Energy Technology Data Exchange (ETDEWEB)

    Whitehead, J C

    2002-06-11

    A four-chamber piston pump is powered by decomposed 85% hydrogen peroxide. The performance envelope of the evolving 400 gram pump has been expanded to 172 cc/s water flow at discharge pressures near 5 MPa. A gas generator cycle system using the pump has been tested under similar conditions of pressure and flow. The powerhead gas is derived from a small fraction of the pumped hydrogen peroxide, and the system starts from tank pressures as low as 0.2 MPa. The effects of steam condensation on performance have been evaluated.

  13. Applications of hydrogen peroxide in electrochemical technology

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez Gallegos, Alberto Armando

    1998-12-01

    It is demonstrated that hydrogen peroxide can be produced with a current efficiency of 40-70% by the cathodic reduction of oxygen at a reticulated vitreous carbon electrode in a divided flow-cell using catholytes consisting of aqueous chloride or sulphate media, pH >>{sub 2}. The supporting electrolyte does not influence either the current efficiency for H{sub 2}O{sub 2} or its rate of production. The current efficiency for H{sub 2}O{sub 2} is not a strong function of the potential and this suggests that 2e- and 4e- reduction of oxygen occurs in parallel at different sites on the carbon surface. Voltammetry experiments showed that (a) the I-E response for oxygen reduction at pH >>{sub 2} is a function of the electrode surface and/or the supporting electrolyte; (b) both H{sub 2} evolution and oxygen reduction are retarded on carbon with increasing ionic strength; (c) the presence of ferrous ions lead to the homogeneous decomposition of H{sub 2}O{sub 2} away from the cathode surface but their effectiveness as a catalyst for this decomposition depends on their speciation in solution which changes during an electrolysis. The use of a three-dimensional electrode fabricated from reticulated vitreous carbon allows Fenton`s reagent to be electroproduced at a practical rate which makes possible the removal of organics in slightly acidic aqueous media. A wide range of highly toxic organic molecules (phenol, catechol, hydroquinone, p-benzoquinone, oxalic acid, aniline, cresol and amaranth) have been oxidised in mild conditions and a significant fraction of the organic carbon is evolved as CO{sub 2}. In all cases studied the initial chemical oxygen demand (COD) was depleted to levels higher than 85%, indicating a complete mineralisation of the organic pollutants. The life-time of the reticulated vitreous carbon cathode was demonstrated to be over 1000 hours during two and a half years of experiments. During this time the cathode performance was very good, leading to

  14. The selection between apoptosis and necrosis is differentially regulated in hydrogen peroxide-treated and glutathione-depleted human promonocytic cells.

    Science.gov (United States)

    Troyano, A; Sancho, P; Fernández, C; de Blas, E; Bernardi, P; Aller, P

    2003-08-01

    Treatment with 0.2 mM hydrogen peroxide (H(2)O(2)) or with 0.5 mM cisplatin caused caspase-9 and caspase-3 activation and death by apoptosis in U-937 human promonocytic cells. However, treatment with 2 mM H(2)O(2), or incubation with the glutathione suppressor DL-buthionine-(S,R)-sulfoximine (BSO) prior to treatment with cisplatin, suppressed caspase activation and changed the mode of death to necrosis. Treatment with 2 mM H(2)O(2) caused a great decrease in the intracellular ATP level, which was partially prevented by 3-aminobenzamide (3-ABA). Correspondingly, 3-ABA restored the activation of caspases and the execution of apoptosis. By contrast, BSO plus cisplatin did not decrease the ATP levels, and the generation of necrosis by this treatment was not affected by 3-ABA. On the other hand, while all apoptosis-inducing treatments and treatment with 2 mM H(2)O(2) caused Bax translocation from the cytosol to mitochondria as well as cytochrome c release from mitochondria to the cytosol, treatment with BSO plus cisplatin did not. Treatment with cisplatin alone caused Bid cleavage, while BSO plus cisplatin as well as 0.2 and 2 mM H(2)O(2) did not. Bcl-2 overexpression reduced the generation of necrosis by H(2)O(2), but not by BSO plus cisplatin. These results indicate the existence of different apoptosis/necrosis regulatory mechanisms in promonocytic cells subjected to different forms of oxidative stress.

  15. Distillation Kinetics of Solid Mixtures of Hydrogen Peroxide and Water and the Isolation of Pure Hydrogen Peroxide in Ultrahigh Vacuum

    Science.gov (United States)

    Teolis, B. D.; Baragiola, R. A.

    2006-01-01

    We present results of the growth of thin films of crystalline H2O2 and H2O2.2H2O (dihydrate) in ultrahigh vacuum by distilling an aqueous solution of hydrogen peroxide. We traced the process using infrared reflectance spectroscopy, mass loss on a quartz crystal microbalance, and in a few cases ultraviolet-visible reflectance. We find that the different crystalline phases-water, dihydrate, and hydrogen peroxide-have very different sublimation rates, making distillation efficient to isolate the less volatile component, crystalline H2O2.

  16. Hydrogen peroxide in breath condensate during a common cold

    NARCIS (Netherlands)

    R.Q. Jöbsis (Rijn); S.L. Schellekens; A. Fakkel-Kroesbergen (Anoeska); R.H. Raatgeep (Rolien); J.C. de Jongste (Johan)

    2001-01-01

    textabstractBackground: Hydrogen peroxide (H2O2) in exhaled air condensate is elevated in inflammatory disorders of the lower respiratory tract. It is unknown whether viral colds contribute to exhaled H2O2. Aim: To assess exhaled H2O2during and after a common cold. Methods: We examined H2O2in the

  17. Natural manganese deposits as catalyst for decomposing hydrogen peroxide

    NARCIS (Netherlands)

    Knol, A.H.; Lekkerkerker-Teunissen, K.; Van Dijk, J.C.

    2015-01-01

    Drinking water companies (are intending to) implement advanced oxidation processes (AOP) in their treatment schemes to increase the barrier against organic micropollutants (OMPs). It is necessary to decompose the excessive hydrogen peroxide after applying AOP to avoid negative effects in the

  18. Hydrogen peroxide in exhaled air of healthy children: reference values

    NARCIS (Netherlands)

    Q. Jobsis (Quirijn); R.H. Raatgeep (Rolien); S.L. Schellekens; W.C.J. Hop (Wim); P.W.M. Hermans (Peter); J.C. de Jongste (Johan)

    1998-01-01

    textabstractAn increased content of hydrogen peroxide (H2O2), a marker of inflammation, has been described in the condensate of exhaled air from adults and children with inflammatory lung disorders, including asthma. However, the normal range of [H2O2] in the exhaled

  19. Electrochemical reduction of hydrogen peroxide on stainless steel

    Indian Academy of Sciences (India)

    Electrochemical reduction of hydrogen peroxide is studied on a sand-blasted stainless steel (SSS) electrode in an aqueous solution of NaClO4. The cyclic voltammetric reduction of H2O2 at low concentrations is characterized by a cathodic peak at -0.40 V versus standard calomel electrode (SCE). Cyclic voltammetry is ...

  20. Selective Electrochemical Generation of Hydrogen Peroxide from Water Oxidation

    DEFF Research Database (Denmark)

    Viswanathan, Venkatasubramanian; Hansen, Heine Anton; Nørskov, Jens K.

    2015-01-01

    evolution and form hydrogen peroxide. Using density functional theory calculations, we show that the free energy of adsorbed OH* can be used to determine selectivity trends between the 2e(-) water oxidation to H2O2 and the 4e(-) oxidation to O2. We show that materials which bind oxygen intermediates...

  1. Enhanced accumulation of root hydrogen peroxide is associated ...

    African Journals Online (AJOL)

    Enhanced accumulation of root hydrogen peroxide is associated with reduced antioxidant enzymes under isoosmotic NaCl and Na2SO4 salinities. Mahmoudi Hela, Baatour Olfa, Ben Salah Imen, Nasri Nawel, Wissal Abidi, Huang Jun, Zargouni Hanen, Hannoufa Abdelali, Lachaal Mokhtar, Ouerghi Zeineb ...

  2. Polyhexanide and hydrogen peroxide inhibit proteoglycan synthesis of human chondrocytes.

    Science.gov (United States)

    Röhner, Eric; Hoff, Paula; Winkler, Tobias; von Roth, Philipp; Seeger, Jörn Bengt; Perka, Carsten; Matziolis, Georg

    2011-03-01

    The use of local antiseptics is a common method in septic joint surgery. We tested polyhexanide and hydrogen peroxide, two of the most frequently used antiseptics with high efficacy and low toxicity. The purpose of this study was to evaluate the effects of both antiseptics on the extracellular cartilaginous matrix synthesis of human chondrocytes. Chondrocytes were isolated from donated human knee joints, embedded in alginate beads, and incubated for 10 and 30 minutes with polyhexanide (0.04%), hydrogen peroxide (3%), or phosphate-buffered saline (PBS) for control. Cartilaginous matrix production was quantified through light microscopic analysis of Alcian blue staining. Cell number and morphology were detected by histological analysis. Chondrocytes showed a decreased intensity of blue colouring after antiseptic treatment versus PBS. In contrast to that, neither the cell number per view field nor the cell morphology differed between the groups. Polyhexanide has more toxic potential than hydrogen peroxide. Based on the fact that the cell number and morphology was not altered by the substances at the examined concentrations, the lower intensity of Alcian blue staining of treated chondrocytes indicates a decreased cartilage-specific matrix synthesis by polyhexanide more than by hydrogen peroxide and control.

  3. A Comparative Study of the Effect of Hydrogen Peroxide and ...

    African Journals Online (AJOL)

    Contact lens cases contaminated with Pseudomonas aeruginosa are a major risk factor in ocular infections. A comparative study of the effect of 0.6% hydrogen peroxide and 0.0005% polyhexamethlylene biguanide on Pseudomonas aerugunosa isolated from three different sources, and cultured on nutrient agar plates and ...

  4. Electrocatalytic oxidation of hydrogen peroxide by poly(Ni -teta ...

    Indian Academy of Sciences (India)

    Administrator

    Electrocatalytic oxidation of hydrogen peroxide by poly(Ni. II. -teta) complex modified electrodes. V GANESAN and R RAMARAJ. School of Chemistry, Madurai Kamaraj University, Madurai 625 021, India. Electrochemical methods based on the direct reduction or oxidation of substrate molecules at bare electrodes are often ...

  5. Effect of hydrogen peroxide and thiourea on dormancy breaking of ...

    African Journals Online (AJOL)

    Potato (Solanum tuberosum L.) microtubers or field-grown tubers have a dormant apical bud (also called tuber dormancy). They do not readily sprout even if environmental conditions are favorable, including optimum temperature and humidity. The objective of this study was to evaluate the involvement of hydrogen peroxide ...

  6. Assessment of hydrogen peroxide in breath condensate as an ...

    African Journals Online (AJOL)

    Ehab

    Assessment of hydrogen peroxide in breath condensate as an inflammatory marker in asthmatic children. INTRODUCTION. Asthma is a leading cause of chronic illness in childhood. As many as 10-15% of boys and 7-10% of girls may have asthma at sometime during childhood. Current data support the hypothesis that ...

  7. Genotoxic effect induced by hydrogen peroxide in human hepatoma ...

    African Journals Online (AJOL)

    Background: Hydrogen peroxide (H2O2) is a common reactive oxygen intermediate generated by various forms of oxidative stress. Aim: The aim of this study was to investigate the DNA damage capacity of H2O2 in HepG2 cells. Methods: Cells were treated with ...

  8. Salinity-gradient energy driven microbial electrosynthesis of hydrogen peroxide

    DEFF Research Database (Denmark)

    Li, Xiaohu; Angelidaki, Irini; Zhang, Yifeng

    2017-01-01

    Hydrogen peroxide (H2O2) as a strong oxidant, is widely used in various chemical industries and environmental remediation processes. In this study, we developed an innovative method for cost-effective production of H2O2 by using a microbial reverse-electrodialysis electrolysis cell (MREC...

  9. Hydrogen peroxide as a signal controlling plant programmed cell death

    NARCIS (Netherlands)

    Gechev, Tsanko S.; Hille, Jacques

    2005-01-01

    Hydrogen peroxide (H2O2) has established itself as a key player in stress and programmed cell death responses, but little is known about the signaling pathways leading from H2O2 to programmed cell death in plants. Recently, identification of key regulatory mutants and near-full genome coverage

  10. The basic chemistry and photochemistry behind hydrogen peroxide tooth whitening

    NARCIS (Netherlands)

    Young, N.D.; Fairley, P.D.; Mohan, V.; Jumeaux, C.

    2013-01-01

    Tooth whitening using hydrogen peroxide gel formulation is a complexprocess which involves both chemistry and physics, and there is still some controversy about the efficiency of whitening processes, particularly with respect to the roles of temperature and irradiation with light. In this work we

  11. Differential sensitivity to hydrogen peroxide of dopaminergic and noradrenergic neurotransmission in rat brain slices.

    NARCIS (Netherlands)

    Langeveld, C.H.; Schepens, E.; Stoof, J.C.; Bast, A.; Drukarch, B.

    1995-01-01

    Oxidative stress, induced by hydrogen peroxide, has been implicated in the pathogenesis of Parkinson's disease. Only scarce information is available if and how hydrogen peroxide, a side product of catecholamine (CA) breakdown, interferes with CAergic neurotransmission. Therefore, we investigated the

  12. Hydrogen peroxide oxidant fuel cell systems for ultra-portable applications

    Science.gov (United States)

    Valdez, T. I.; Narayanan, S. R.

    2001-01-01

    This paper will address the issues of using hydrogen peroxide as an oxidant fuel in a miniature DMFC system. Cell performance for DMFC based fuel cells operating on hydrogen peroxide will be presented and discussed.

  13. HYDROGEN PEROXIDE PRODUCTION ACTIVITY AND ADHESIVE PROPERTIES OF AEROCOCCI, ISOLATED IN WOMEN

    National Research Council Canada - National Science Library

    Stepanskyi D.O; Kremenchutsky G.M; Chuyko V.I; Koshova I.P; Khomiak O.V; Krushynska T.Y

    2017-01-01

    ...: the production of organic acids, antibiotics, lysozyme, hydrogen peroxide and others. Ability to produce hydrogen peroxide under aerobic conditions and in a state of relative anaerobiosis was established in aerococci...

  14. Hydrogen Peroxide: A Key Chemical for Today's Sustainable Development.

    Science.gov (United States)

    Ciriminna, Rosaria; Albanese, Lorenzo; Meneguzzo, Francesco; Pagliaro, Mario

    2016-12-20

    The global utilization of hydrogen peroxide, a green oxidant that decomposes in water and oxygen, has gone from 0.5 million tonnes per year three decades ago to 4.5 million tonnes per year in 2014, and is still climbing. With the aim of expanding the utilization of this eminent green chemical across different industrial and civil sectors, the production and use of hydrogen peroxide as a green industrial oxidant is reviewed herein to provide an overview of the explosive growth of its industrial use over the last three decades and of the state of the art in its industrial manufacture, with important details of what determines the viability of the direct production from oxygen and hydrogen compared with the traditional auto-oxidation process. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Catalytic hydrogen peroxide decomposition La1-xSrxCoO3-δ perovskite oxides

    NARCIS (Netherlands)

    Dam, T.V.A.; Olthuis, Wouter; Bergveld, Piet; van den Berg, Albert

    2005-01-01

    Lanthanide perovskite oxides are mentioned as material for hydrogen peroxide sensor because they can catalytically decompose hydrogen peroxide in an aqueous medium. The catalytic properties of these perovskite oxides to hydrogen peroxide are suggested due to their oxygen vacancies influenced by the

  16. 21 CFR 172.167 - Silver nitrate and hydrogen peroxide solution.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Silver nitrate and hydrogen peroxide solution. 172... FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.167 Silver nitrate and hydrogen peroxide solution. An aqueous solution containing a mixture of silver nitrate and hydrogen peroxide may be safely used...

  17. Selective production of hydrogen peroxide and oxidation of hydrogen sulfide in an unbiased solar photoelectrochemical cell

    OpenAIRE

    Zong, Xu; Chen, Hongjun; Seger, Brian; Pedersen, Thomas; Dargusch, Matthew S.; McFarland, Eric W.; Li, Can; Wang, Lianzhou

    2014-01-01

    A solar-to-chemical conversion process is demonstrated using a photoelectrochemical cell without external bias for selective oxidation of hydrogen sulfide (H2S) to produce hydrogen peroxide (H2O2) and sulfur (S). The process integrates two redox couples anthraquinone/anthrahydroquinone and I−/I3−, and conceptually illustrates the remediation of a waste product for producing valuable chemicals.

  18. Selective production of hydrogen peroxide and oxidation of hydrogen sulfide in an unbiased solar photoelectrochemical cell

    DEFF Research Database (Denmark)

    Zong, Xu; Chen, Hongjun; Seger, Brian

    2014-01-01

    A solar-to-chemical conversion process is demonstrated using a photoelectrochemical cell without external bias for selective oxidation of hydrogen sulfide (H2S) to produce hydrogen peroxide (H2O2) and sulfur (S). The process integrates two redox couples anthraquinone/anthrahydroquinone and I−/I3......−, and conceptually illustrates the remediation of a waste product for producing valuable chemicals....

  19. Advances in Hypergolic Propellants: Ignition, Hydrazine, and Hydrogen Peroxide Research

    Directory of Open Access Journals (Sweden)

    Stephen M. Davis

    2014-01-01

    Full Text Available A review of the literature pertaining to hypergolic fuel systems, particularly using hydrazine or its derivatives and hydrogen peroxide, has been conducted. It has been shown that a large effort has been made towards minimizing the risks involved with the use of a toxic propellant such as the hydrazine. Substitution of hydrazines for nontoxic propellant formulations such as the use of high purity hydrogen peroxide with various types of fuels is one of the major areas of study for future hypergolic propellants. A series of criteria for future hypergolic propellants has been recommended, including low toxicity, wide temperature range applicability, short ignition delay, high specific impulse or density specific impulse, and storability at room temperature.

  20. Determination of peracetic acid and hydrogen peroxide in the mixture

    OpenAIRE

    Bodiroga Milanka; Ognjanović Jasminka

    2002-01-01

    Iodometric and permanganometric titrations were used for determination of peracetic acid and hydrogen peroxide (H2O2) in the mixture. Two procedures were described and compared. Titrations could be done in only one vessel, in the same reaction mixture, when iodometric titration of peracetic acid was continued after the permanganometric titration of H2O2, (procedure A). Peracetic acid and H2O2, as oxidizing agents, reacted with potassium iodide in an acid medium, evolving iodine. This reaction...

  1. Ultraviolet absorption spectrum of hydrogen peroxide vapor. [for atmospheric abundances

    Science.gov (United States)

    Molina, L. T.; Schinke, S. D.; Molina, M. J.

    1977-01-01

    The ultraviolet absorption cross sections of hydrogen peroxide vapor have been determined over the wavelength range 210 to 350 nm at 296 K. At the longer wavelengths, the gas phase absorptivities are significantly larger than the corresponding values in condensed phase. The atmospheric H2O2 photodissociation rate for overhead sun at the earth's surface is estimated to be about 1.3 x 10 to the -5th/sec.

  2. A sensitive nonenzymatic hydrogen peroxide sensor based on ...

    Indian Academy of Sciences (India)

    nanocomposites were then applied to study the electrocatalytic reduction of hydrogen peroxide (H2O2) in 0.01 M. pH 7.0 phosphate buffer medium. Then the Fe3O4–Fe2O3 nanocomposites were used as active electrode material of electrochemical sensors for H2O2 detection The detection sensitivity of the sensor was ...

  3. Genotoxic effect induced by hydrogen peroxide in human hepatoma ...

    African Journals Online (AJOL)

    2010-01-13

    Jan 13, 2010 ... Background: Hydrogen peroxide (H2O2) is a common reactive oxygen intermediate generated by various forms of oxidative stress. Aim: The aim of this study was to investigate the DNA damage capacity of H2O2 in HepG2 cells. Methods: Cells were treated with H2O2 at concentrations of 25 mM or 50 mM ...

  4. Reactions of zirconium and hafnium fluoride hydrates with hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Gerasimova, S.O.; Polishchuk, S.A.; Avkhutskii, L.M.; Kalennik, V.M. (AN SSSR, Vladivostok. Inst. Khimii)

    1981-01-01

    Zirconium peroxofluoride of ZrO/sub 2/F/sub 2/x2H/sub 2/O composition is prepared by interaction of zirconium tetrafluoride trihydrate with hydrogen peroxide at pH 2-3. Hafnium peroxofluoride compound is not formed under similar conditions. It can be caused by their structural peculiarities for the compounds are not isostructural IR, PMR and NMR spectra for Zr peroxofluoride are presented.

  5. A sensitive nonenzymatic hydrogen peroxide sensor based on ...

    Indian Academy of Sciences (India)

    The obtained Fe3O4–Fe2O3 nanocomposites were then applied to study the electrocatalytic reduction of hydrogen peroxide (H2O2) in 0.01 M pH 7.0 phosphate buffer medium. Then the Fe3O4–Fe2O3 nanocomposites were used as active electrode material of electrochemical sensors for H2O2 detection The detection ...

  6. Nitrophenylboronic acids as highly chemoselective probes to detect hydrogen peroxide in foods and agricultural products.

    Science.gov (United States)

    Lu, Chun-Ping; Lin, Chieh-Ti; Chang, Ching-Ming; Wu, Shih-Hsiung; Lo, Lee-Chiang

    2011-11-09

    Hydrogen peroxide is commonly used in the food processing industry as a chlorine-free bleaching and sterilizing agent, but excessive amounts of residual hydrogen peroxide have led to cases of food poisoning. Here we describe the development of a novel nonenzymatic colorimetric method for the determination of residual hydrogen peroxide in foods and agricultural products. Nitrophenylboronic acids chemoselectively react with hydrogen peroxide under alkaline conditions to produce yellow nitrophenolates. Of the three nitrophenylboronic acid isomers tested, the p-isomer displayed the highest sensitivity for hydrogen peroxide and the fastest reaction kinetics. The reaction product, p-nitrophenolate, has an absorption maximum at 405 nm and a good linear correlation between the hydrogen peroxide concentration and the A(405) values was obtained. We successfully applied this convenient and rapid method for hydrogen peroxide determination to samples of dried bean curds and disposable chopsticks, thereby demonstrating its potential in foods and agricultural industries.

  7. The kinetic study of oxidation of iodine by hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Cantrel, L. [Institut de Protection et de Surete Nucleaire, IPNS, CEN Cadarache, Saint Paul lez Durance (France); Chopin, J. [Laboratoire d`Electrochimie Inorganique, ENSSPICAM, Marseille (France)

    1996-12-01

    Iodine chemistry is one of the most important subjects of research in the field of reactor safety because this element can form volatile species which represent a biological hazard for environment. As the iodine and the peroxide are both present in the sump of the containment in the event of a severe accident on a light water nuclear reactor, it can be important to improve the knowledge on the reaction of oxidation of iodine by hydrogen peroxide. The kinetics of iodine by hydrogen peroxide has been studied in acid solution using two different analytical methods. The first is a UV/Vis spectrophotometer which records the transmitted intensity at 460 nm as a function of time to follow the decrease of iodine concentration, the second is an amperometric method which permits to record the increase of iodine+1 with time thanks to the current of reduction of iodine+1 to molecular iodine. The iodine was generated by Dushman reaction and the series of investigations were made at 40{sup o}C in a continuous stirring tank reactor. The influence of the initial concentrations of iodine, iodate, hydrogen peroxide, H{sup +} ions has been determined. The kinetics curves comprise two distinct chemical phases both for molecular iodine and for iodine+1. The relative importance of the two processes is connected to the initial concentrations of [I{sub 2}], [IO{sub 3}{sup -}], [H{sub 2}O{sub 2}] and [H{sup +}]. A rate law has been determined for the two steps for molecular iodine. (author) figs., tabs., 22 refs.

  8. Redox changes in the chloroplast and hydrogen peroxide are essential for regulation of C(3)-CAM transition and photooxidative stress responses in the facultative CAM plant Mesembryanthemum crystallinum L.

    Science.gov (United States)

    Slesak, Ireneusz; Karpinska, Barbara; Surówka, Ewa; Miszalski, Zbigniew; Karpinski, Stanislaw

    2003-06-01

    Mesembryanthemum crystallinum, a facultative halophyte and C(3)-Crassulacean acid metabolism (CAM) intermediate plant, has become a favoured plant for studying stress response mechanisms during C(3)-CAM shifts. One hour of exposure to excess light (EL) caused inhibition of photosynthetic electron transport in M. crystallinum leaves as indicated by chlorophyll a fluorescence measurements. This was accompanied by an increase in NADP-malic enzyme (ME), one of the key cytosolic enzymes involved in CAM, and by a general increase in superoxide dismutase (SOD) activity. In contrast, NAD-ME activity (the mitochondrial form of ME) was not affected by EL. Exposure to EL and 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (DBMIB) treatment of a whole plant in low light induced hydrogen peroxide (H(2)O(2)) and C(3) to CAM transition. In contrast, treatment with 3-3,4-dichlorophenyl-1,1-dimethyl urea (DCMU) has blocked high light-induced H(2)O(2) accumulation and C(3)-CAM transition. Moreover, the abundance of transcripts encoding different SODs, ascorbate peroxidase and SOD activity was differently regulated by DCMU and DBMIB. Results of applying EL or high light, H(2)O(2) and photosynthetic electron transport inhibitors suggest that the redox events in the vicinity of PSII and/or PSI and photo-produced H(2)O(2) play a major role in the regulation of C(3)-CAM transition and photooxidative stress responses in M. crystallinum.

  9. Hydrogen peroxide synthesis: an outlook beyond the anthraquinone process.

    Science.gov (United States)

    Campos-Martin, Jose M; Blanco-Brieva, Gema; Fierro, Jose L G

    2006-10-27

    Hydrogen peroxide (H2O2) is widely used in almost all industrial areas, particularly in the chemical industry and environmental protection. The only degradation product of its use is water, and thus it has played a large role in environmentally friendly methods in the chemical industry. Hydrogen peroxide is produced on an industrial scale by the anthraquinone oxidation (AO) process. However, this process can hardly be considered a green method. It involves the sequential hydrogenation and oxidation of an alkylanthraquinone precursor dissolved in a mixture of organic solvents followed by liquid-liquid extraction to recover H2O2. The AO process is a multistep method that requires significant energy input and generates waste, which has a negative effect on its sustainability and production costs. The transport, storage, and handling of bulk H2O2 involve hazards and escalating expenses. Thus, novel, cleaner methods for the production of H2O2 are being explored. The direct synthesis of H2O2 from O2 and H2 using a variety of catalysts, and the factors influencing the formation and decomposition of H2O2 are examined in detail in this Review.

  10. BIOSORPTION OF CONGO RED BY HYDROGEN PEROXIDE TREATED TENDU WASTE

    Directory of Open Access Journals (Sweden)

    G. K. Nagda ، V. S. Ghole

    2009-07-01

    Full Text Available Solid wastes from agro-industrial operations can be recycled as non-conventional adsorbents if they are inert and harmless and reduce the cost of wastewater treatment. Tendu leaf Diospyros melanoxylon is the second largest forest product in India after timber and is exclusively used in making local cigarette called Bidi. Waste leaf cutting remaining after making cigarette was used in present study as a biosorbent for the removal of Congo red dye from aqueous solution. It was treated with hydrogen peroxide to obtain biosorbent with increased adsorption capacity. Batch type experiments were conducted to study the influence of different parameters such as pH, initial dye concentration and dosage of adsorbent on biosorption evaluated. The adsorption occured very fast initially and attains equilibrium within 60 min at pH= 6.2 and the equilibrium attained faster after hydrogen peroxide modification. Kinetic studies showed that the biosorption of Congo red on tendu waste followed pseudo-second-order rate equation. The data fitted well to Langmuir and Freundlich isotherm models. Comparison was done on the extent of biosorption between untreated and treated forms of the tendu waste. The maximum adsorption capacity for untreated tendu waste was found to be 46.95 mg/g, which was enhanced by 2.8 times after hydrogen peroxide treatment and was found to be 134.4 mg/g. The adsorption process was in conformity with Freundlich and Langmuir isotherms for Congo red adsorption from aqueous solution. The study demonstrated use of milder chemical treatment of tendu waste to obtain a biosorbent with enhanced dye removal capacity.

  11. Efficacy of hydrogen peroxide for treating saprolegniasis in channel catfish

    Science.gov (United States)

    Howe, G.E.; Gingerich, W.H.; Dawson, V.K.; Olson, J.J.

    1999-01-01

    Hatchery-reared fish and their eggs are commonly afflicted with saprolegniasis, a fungal disease that can cause significant losses in production. Fish culturists need safe and effective fungicides to minimize losses and meet production demands. The efficacy of hydrogen peroxide was evaluated for preventing or controlling mortality associated with saprolegniasis in channel catfish Ictalurus punctatus. Saprolegniasis was systematically induced in channel catfish so various therapies could be evaluated in a controlled laboratory environment. Both prophylactic and therapeutic hydrogen peroxide bath treatments of 50, 100, and 150 ??L/L for 1 h were administered every other day for seven total treatments. All untreated positive control fish died of saprolegniasis during the prophylactic and therapeutic tests. Hydrogen peroxide treatments of 150 ??L/L were harmful (relative to lower concentrations) to test fish and resulted in 73-95% mortality. Mortality was attributed to a combination of abrasion, temperature, chemical treatment, and disease stressors. Treatments of 100 ??L/L were less harmful (relatively) but also appeared to contribute to mortality (60-79%). These treatments, however, significantly reduced the incidence of mortality and infection compared with those observed for fish of the positive control or 150-??L/L treatment groups. Overall, treatments of 50 ??L/L were found to be the most safe and effective of those tested. Mortality with this concentration ranged from 16% in therapeutic tests to 41% in prophylactic tests. The statistical model employed estimated that the optimum treatment concentration for preventing or controlling mortality, reducing the incidence of infections, and enhancing the recovery of infected fish was 75 ??L H2O2/L.

  12. Removal of Reactive Red 198 by Nanoparticle Zero Valent Iron in the Presence of Hydrogen Peroxide

    Directory of Open Access Journals (Sweden)

    Siroos Shojaei

    2017-04-01

    Full Text Available Although dyes are widely used in textile industries, they are carcinogenic, teratogenic and mutagenic. Industries discharge their wastewater containing a variety of colors into water resources and make harmful effect on the environment. The present study aims to Evaluate removal of reactive red 198 by nanoparticle zero valent iron (NZVI in the presence of hydrogen peroxide from aqueous solution. The effective parameters on the removal of dye such as the hydrogen peroxide concentration of NZVI, contact time, pH and dye concentration were investigated and optimized. According to the results, the combination of NZVI with hydrogen peroxide is more effective than single hydrogen peroxide. At pH = 4, contact time= 40 min, 200 M of hydrogen peroxide, dye concentration= 75 mg/L and concentration of NZVI 2g/L, color removal was achieved 91% approximately. Based on the results of experiments, using hydrogen peroxide- NZVI has high efficiency in removal of azo dye type.

  13. Apparatus and method for treating pollutants in a gas using hydrogen peroxide and UV light

    Science.gov (United States)

    Cooper, Charles David (Inventor); Clausen, Christian Anthony (Inventor)

    2005-01-01

    An apparatus for treating pollutants in a gas may include a source of hydrogen peroxide, and a treatment injector for creating and injecting dissociated hydrogen peroxide into the flow of gas. The treatment injector may further include an injector housing having an inlet, an outlet, and a hollow interior extending therebetween. The inlet may be connected in fluid communication with the source of hydrogen peroxide so that hydrogen peroxide flows through the hollow interior and toward the outlet. At least one ultraviolet (UV) lamp may be positioned within the hollow interior of the injector housing. The at least one UV lamp may dissociate the hydrogen peroxide flowing through the tube. The dissociated hydrogen peroxide may be injected into the flow of gas from the outlet for treating pollutants, such as nitrogen oxides.

  14. Hydrogen peroxide distribution, production, and decay in boreal lakes

    OpenAIRE

    Häkkinen, P J; Anesio, Alexandre Magno; Granéli, Wilhelm

    2004-01-01

    The distribution, production, and decay of hydrogen peroxide (H2O2) were studied in 10 boreal lakes of differing physical-chemical characteristics. Diurnal and vertical fluctuations in H2O2 concentration were followed in the lakes by sampling at six depths three times per day. In addition, incubations of water filtered through 0.2-mu mesh were made under artificial irradiation to study the abiotic production and decay of H2O2. H2O2 concentrations after 8 h of artificial irradiation were signi...

  15. Historical Survey: German Research on Hydrogen Peroxide/Alcohol Explosives

    Energy Technology Data Exchange (ETDEWEB)

    Parmeter, John E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-01-01

    Discussion of HP/fuel explosives in the scientific literature dates back to at least 1927. A paper was published that year in a German journal entitled On Hydrogen Peroxide Explosives [Bamberger and Nussbaum 1927]. The paper dealt with HP/cotton/Vaseline formulations, specifically HP89/cotton/Vaseline (76/15/9) and (70/8.5/12.5). The authors performed experiments with charge masses of 250-750 g and charge diameters of 35-45 mm. This short paper provides brief discussion on the observed qualitative effects of detonations but does not report detonation velocities.

  16. Hydrogen peroxide-based propulsion and power systems.

    Energy Technology Data Exchange (ETDEWEB)

    Melof, Brian Matthew; Keese, David L.; Ingram, Brian V.; Grubelich, Mark Charles; Ruffner, Judith Alison; Escapule, William Rusty

    2004-04-01

    Less toxic, storable, hypergolic propellants are desired to replace nitrogen tetroxide (NTO) and hydrazine in certain applications. Hydrogen peroxide is a very attractive replacement oxidizer, but finding acceptable replacement fuels is more challenging. The focus of this investigation is to find fuels that have short hypergolic ignition delays, high specific impulse, and desirable storage properties. The resulting hypergolic fuel/oxidizer combination would be highly desirable for virtually any high energy-density applications such as small but powerful gas generating systems, attitude control motors, or main propulsion. These systems would be implemented on platforms ranging from guided bombs to replacement of environmentally unfriendly existing systems to manned space vehicles.

  17. Enzymatic generation of hydrogen peroxide shows promising antifouling effect

    DEFF Research Database (Denmark)

    Kristensen, J.B.; Olsen, Stefan Møller; Laursen, B.S.

    2010-01-01

    The antifouling (AF) potential of hydrogen peroxide (H2O2) produced enzymatically in a coating containing starch, glucoamylase, and hexose oxidase was evaluated in a series of laboratory tests and in-sea field trials. Dissolved H2O2 inhibited bacterial biofilm formation by eight of nine marine...... Proteobacteria, tested in microtiter plates. However, enzymatically produced H2O2 released from a coating did not impede biofilm formation by bacteria in natural seawater tested in a biofilm reactor. A field trial revealed a noticeable effect of the enzyme system: after immersion in the North Sea for 97 days...

  18. Hydrogen peroxide-dependent antibacterial action of Melilotus albus honey.

    Science.gov (United States)

    Sowa, P; Grabek-Lejko, D; Wesołowska, M; Swacha, S; Dżugan, M

    2017-07-01

    Honey originating from different floral sources exhibits the broad spectrum of antibacterial activity as a result of the presence of hydrogen peroxide as well as nonperoxide bioactive compounds. The mechanisms of antibacterial activity of Polish melilot honey were investigated for the first time. Polish melilot honey samples (Melilotus albus biennial = 3 and annual = 5, Melilotus officinalis = 1) were collected directly from beekeepers and analysed for pollen profile, basic physicochemical parameters, antioxidant capacity, radical scavenging activity, total phenolic contents as well as antibacterial properties against pathogenic bacteria Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Salmonella spp. The physicochemical properties of melilot honey were specific for light-coloured unifloral honey samples and were not dependent on its botanical and geographical origin (P > 0·05). All tested honey samples exhibited inhibitory activity (above 90%) against Gram-positive bacteria at the concentration of 12·5-25%. Above 30-50% of antibacterial activity of melilot honey was connected with glucose oxidase enzyme action and was destroyed in the presence of catalase. Hydrogen peroxide-dependent antibacterial activity of honey was inversely correlated with its radical scavenging activity (r = -0·67) and phenolic compounds (r = -0·61). Antibacterial action of melilot honey depends not only on hydrogen peroxide produced by glucose oxidase, but also on other nonperoxide bioactive components of honey. Melilot honey is used in traditional medicine as an anticoagulant agent due to the possibility of the presence of the coumarin compounds which are specific for Melilotus plant. Melilotus albus is rarely used to produce honey, and antibacterial properties of this variety of honey had not been studied yet. Nine samples of melilot honey produced in different regions of Poland were analysed according to their antibacterial activity which was correlated

  19. Hydrogen peroxide as an effective disinfectant for Pasteurella multocida.

    Science.gov (United States)

    Jung, In-Soo; Kim, Hyun-Jung; Jung, Won-Yong; Kim, Chan-Wha

    2014-07-01

    Pasteurella multocida (P. multocida) infections vary widely, from local infections resulting from animal bites and scratches to general infections. As of yet, no vaccine against P. multocida has been developed, and the most effective way to prevent pathogenic transmission is to clean the host environment using disinfectants. In this study, we identified which disinfectants most effectively inhibited environmental isolates of P. multocida. Three readily available disinfectants were compared: 3% hydrogen peroxide (HP), 70% isopropyl alcohol, and synthetic phenol. In suspension tests and zone inhibition tests, 3% HP was the most promising disinfectant against P. multocida.

  20. Chemiluminescent Nanomicelles for Imaging Hydrogen Peroxide and Self-Therapy in Photodynamic Therapy

    OpenAIRE

    Rui Chen; Luzhong Zhang; Jian Gao; Wei Wu; Yong Hu; Xiqun Jiang

    2011-01-01

    Hydrogen peroxide is a signal molecule of the tumor, and its overproduction makes a higher concentration in tumor tissue compared to normal tissue. Based on the fact that peroxalates can make chemiluminescence with a high efficiency in the presence of hydrogen peroxide, we developed nanomicelles composed of peroxalate ester oligomers and fluorescent dyes, called peroxalate nanomicelles (POMs), which could image hydrogen peroxide with high sensitivity and stability. The potential application o...

  1. Effect of hydrogen peroxide and sodium perborate on the microhardness of human enamel and dentin.

    Science.gov (United States)

    Lewinstein, I; Hirschfeld, Z; Stabholz, A; Rotstein, I

    1994-02-01

    The effect of 30% hydrogen peroxide and a paste of sodium perborate mixed with hydrogen peroxide at different temperatures and time intervals on the microhardness of human enamel and dentin was examined. Intact extracted human teeth were sectioned, embedded in acrylic resin, polished, and divided into four test groups related to surface treatment. The groups were 30% hydrogen peroxide at 37 degrees C, 30% hydrogen peroxide at 50 degrees C in an illuminated chamber, a paste of sodium perborate mixed with hydrogen peroxide at 37 degrees C, and a paste of sodium perborate mixed with hydrogen peroxide at 50 degrees C in an illuminated chamber. Teeth treated with distilled water at either 37 degrees C or 50 degrees C served as controls. The results indicated that treatment with 30% hydrogen peroxide reduced the microhardness of both enamel and dentin. This reduction was statistically significant after 5-min treatment for the dentin and after 15-min treatment for the enamel (p sodium perborate mixed with hydrogen peroxide did not alter the microhardness of either the enamel or dentin at the tested temperatures and time intervals. It is therefore suggested that the use of high concentrations of hydrogen peroxide for bleaching purposes should be limited. Sodium perborate appears to be a less damaging bleaching agent.

  2. [Establishment of DNA oxidative damage model in colorectal crypt cells by hydrogen peroxide].

    Science.gov (United States)

    Cai, Shan-rong; Zheng, Shu; Zhang, Su-zhan; Peng, Jia-ping

    2006-07-01

    To induce DNA oxidative damage in colorectal crypt cells by hydrogen peroxide in vitro. Hydrogen peroxide was diluted into 100, 50, 10, 5 and 1 micromol/L with RPMI 1640. Colorectal crypt cells were treated with peroxide for 10 min, 30 min, 1 h, 1.5 h, 12 h and 24 h respectively. The survival of colorectal crypt cell was measured by MTT method, and the DNA oxidative damage special product, 8-OhdG was detected with immunohistochemical staining. Liner regression was used to measure the time trend of survival rate with SPSS 10.0 software. Survival rate of colorectal crypt cell was 60% and 80% after 10 min of hydrogen peroxide treatment. The longer treatment of hydrogen peroxide, the lower survival rate; the survival rate was reduced to 30% in 24 h. After 10 or 30 min treatment of 100 or 50 micromol/L hydrogen peroxide, the survival rates of colorectal crypt cells were reduced by 20% compared with those of 10, 5 and 1 micromol/L hydrogen peroxide. However, while cells were treated with different concentrations of hydrogen peroxide for 1.0 h or above, there were no differences in cell survival rates. The time trend test results demonstrated that the survival rates of colorectal crypt cells treated with 10, 5 and 1 micromol/L hydrogen peroxide were significantly decreased with the time length of treatment. Colorectal crypt cells treated with different concentrations of hydrogen peroxide for 15 minutes were positively stained brown in cytoplasm and nuclear by immunohistochemistry with 8-OhdG monoclonal antibody. Hydrogen peroxide could induce DNA oxidative damage in colorectal crypt cells. And treated with 1 - 10 micromol/L hydrogen peroxide for 10 - 30 min, DNA oxidative damage is apt to be induced in colorectal crypt cell.

  3. Effect of Hydrogen Peroxide on the Antibacterial Substantivity of Chlorhexidine

    Directory of Open Access Journals (Sweden)

    Shahriar Shahriari

    2010-01-01

    Full Text Available The purpose of this in vitro study was to assess the effect of hydrogen peroxide on the antibacterial substantivity of chlorhexidine (CHX. Seventy-five dentine tubes prepared from human maxillary central and lateral incisor teeth were used. After contamination with Enterococcus faecalis for 14 days, the specimens were divided into five groups as follows: CHX, H2O2, CHX + H2O2, infected dentine tubes (positive control, and sterile dentine tubes (negative control. Dentine chips were collected with round burs into tryptic soy broth, and after culturing, the number of colony-forming units (CFU was counted. The number of CFU was minimum in the first cultures in all experimental groups, and the results obtained were significantly different from each other at any time period (<.05. At the first culture, the number of CFU in the CHX + H2O2 group was lower than other two groups. At the other experimental periods, the CHX group showed the most effective antibacterial action (<.05. Hydrogen peroxide group showed the worst result at all periods. In each group, the number of CFU increased significantly by time lapse (<.05. In conclusion, H2O2 had no additive effect on the residual antibacterial activity of CHX.

  4. Antifungal efficacy of hydrogen peroxide in dental unit waterline disinfection.

    Science.gov (United States)

    Szymańska, Jolanta

    2006-01-01

    The concentration and composition of fungal flora in dental unit waterlines (DUWL) were evaluated. For this purpose, water samples from unit reservoirs and high-speed handpieces, and biofilm samples from the waterline walls from units were collected. Subsequently, analogous samples from DUWL were taken before and after disinfection using agent containing hydrogen peroxide. In the examined samples, the yeast-like fungi Candida albicans and Candida curvata were found. The following species of mould were also identified: Aspergillus amstelodami, Aspergillus fumigatus, Aspergillus glaucus group, Aspergillus (=Eurotium herbariorum) repens, Citromyces spp., Geotrichum candidum, Penicillium (glabrum) frequentans, Penicillium pusillum, Penicillium turolense and Sclerotium sclerotiorum (Sclerotinia sclerotiorum). Before disinfection, Candida curvata and Candida albicans constituted the greatest proportion of the total fungi in the reservoirs water; in the water of handpieces--Candida albicans and Aspergillus glaucus group; and in the biofilm samples--Aspergillus glaucus group and Candida albicans. After disinfection, in all 3 kinds of samples, Candida albicans prevailed, constituting from 31.2-85.7 % of the total fungi. The application of agent containing hydrogen peroxide caused a significant decrease both in the number of total fungi and individual fungal species, which confirms the product effectiveness in fungal decontamination of DUWL.

  5. A Ca2+/calmodulin-binding peroxidase from Euphorbia latex: novel aspects of calcium-hydrogen peroxide cross-talk in the regulation of plant defenses.

    Science.gov (United States)

    Mura, Anna; Medda, Rosaria; Longu, Silvia; Floris, Giovanni; Rinaldi, Andrea C; Padiglia, Alessandra

    2005-11-01

    Calmodulin (CaM) is a ubiquitous Ca(2+) sensor found in all eukaryotes, where it participates in the regulation of diverse calcium-dependent physiological processes. In response to fluctuations of the intracellular concentration of Ca(2+), CaM binds to a set of unrelated target proteins and modulates their activity. In plants, a growing number of CaM-binding proteins have been identified that apparently do not have a counterpart in animals. Some of these plant-specific Ca(2+)/CaM-activated proteins are known to tune the interaction between calcium and H(2)O(2) in orchestrating plant defenses against biotic and abiotic stresses. We previously characterized a calcium-dependent peroxidase isolated from the latex of the Mediterranean shrub Euphorbia characias (ELP) [Medda et al. (2003) Biochemistry 42, 8909-8918]. Here we report the cDNA nucleotide sequence of Euphorbia latex peroxidase, showing that the derived protein has two distinct amino acid sequences recognized as CaM-binding sites. The cDNA encoding for an E. characias CaM was also found and sequenced, and its protein product was detected in the latex. Results obtained from different CaM-binding assays and the determination of steady-state parameters showed unequivocally that ELP is a CaM-binding protein activated by the Ca(2+)/CaM system. To the best of our knowledge, this is the first example of a peroxidase regulated by this classic signal transduction mechanism. These findings suggest that peroxidase might be another node in the Ca(2+)/H(2)O(2)-mediated plant defense system, having both positive and negative effects in regulating H(2)O(2) homeostasis.

  6. A novel bridge between oxidative stress and immunity: the interaction between hydrogen peroxide and human leukocyte antigen G in placental trophoblasts during preeclampsia.

    Science.gov (United States)

    Zhou, Xue; Zhang, Guo-ying; Wang, Jue; Lu, Shou-lian; Cao, Jun; Sun, Li-zhou

    2012-05-01

    The aim of this study was to investigate a possible association between hydrogen peroxide and human leukocyte antigen G (HLA-G) in preeclampsia. We explored the correlation between HLA-G and hydrogen peroxide in preeclamptic (n = 30) and normotensive (n = 30) placentas, which was confirmed by in vitro experiments. Furthermore, RNA interference was used to explore the influence of HLA-G on the proliferation, apoptosis and invasion of HTR-8/SVneo cells when exposed to hydrogen peroxide. We found an inverse correlation between hydrogen peroxide and HLA-G expression in preeclamptic placentas. High levels of hydrogen peroxide could down-regulate HLA-G expression in HTR-8/SVneo. Compared with HLA-G knockdown HTR-8/SVneo, increased proliferation inhibition, higher apoptosis, and decreased cell invasion were found in the cell expressing HLA-G when exposed to hydrogen peroxide. Our findings highlight that high levels of hydrogen peroxide can down-regulate HLA-G expression in trophoblasts during preeclampsia and trophoblasts expressing HLA-G are vulnerable to oxidative stress. Copyright © 2012 Mosby, Inc. All rights reserved.

  7. Polyamine regulates tolerance to water stress in leaves of white clover associated with antioxidant defense and dehydrin genes via involvement in calcium messenger system and hydrogen peroxide signaling

    Directory of Open Access Journals (Sweden)

    Zhou eLi

    2015-10-01

    Full Text Available Endogenous polyamine (PA may play a critical role in tolerance to water stress in plants acting as a signaling molecule activator. Water stress caused increases in endogenous PA content in leaves, including putrescine (Put, spermidine (Spd, and spermine (Spm. Exogenous application of Spd could induce the instantaneous H2O2 burst and accumulation of cytosolic free Ca2+, and activate NADPH oxidase and CDPK gene expression in cells. To a great extent, PA biosynthetic inhibitor reduced the water stress-induced H2O2 accumulation, free cytosolic Ca2+ release, antioxidant enzyme activities and genes expression leading to aggravate water stress-induced oxidative damage, while these suppressing effects were alleviated by the addition of exogenous Spd, indicating PA was involved in water stress-induced H2O2 and cytosolic free Ca2+ production as well as stress tolerance. Dehydrin genes (Y2SK, Y2K, and SK2 were showed to be highly responsive to exogenous Spd. PA-induced antioxidant defense and dehydrin genes expression could be blocked by the scavenger of H2O2 and the inhibitors of H2O2 generation or Ca2+ channels blockers, a calmodulin antagonist, as well as the inhibitor of CDPK. These findings suggested that PA regulated tolerance to water stress in white clover associated with antioxidant defenses and dehydrins via involvement in the calcium messenger system and H2O2 signaling pathways. PA-induced H2O2 production required Ca2+ release, while PA-induced Ca2+ release was also essential for H2O2 production, suggesting an interaction between PA-induced H2O2 and Ca2+ signaling.

  8. Hydrogen peroxide and caustic soda: Dancing with a dragon while bleaching

    Science.gov (United States)

    Peter W. Hart; Carl Houtman; Kolby Hirth

    2013-01-01

    When hydrogen peroxide is mixed with caustic soda, an auto-accelerating reaction can lead to generation of significant amounts of heat and oxygen. On the basis of experiments using typical pulp mill process concentration and temperatures, a relatively simple kinetic model has been developed. Evaluation of these model results reveals that hydrogen peroxide-caustic soda...

  9. An Experimental Investigation of Hypergolic Ignition Delay of Hydrogen Peroxide with Fuel Mixtures

    Science.gov (United States)

    Blevins, John A.; Gostowski, Rudy; Chianese, Silvio

    2003-01-01

    An experimental evaluation of decomposition and ignition delay of hydrogen peroxide at concentrations of 80% to 98% with combinations of hydrocarbon fuels, tertiary amines and transition metal chelates will be presented in the proposed paper. The results will be compared to hydrazine ignition delays with hydrogen peroxide and nitric acid mixtures using the same test apparatus.

  10. Quantifying hydrogen peroxide in iron-containing solutions using leuco crystal violet

    Directory of Open Access Journals (Sweden)

    Schoonen Martin A

    2005-06-01

    Full Text Available Hydrogen peroxide is present in many natural waters and wastewaters. In the presence of Fe(II, this species decomposes to form hydroxyl radicals, that are extremely reactive. Hence, in the presence of Fe(II, hydrogen peroxide is difficult to detect because of its short lifetime. Here, we show an expanded use of a hydrogen peroxide quantification technique using leuco crystal violet (LCV for solutions of varying pH and iron concentration. In the presence of the biocatalyst peroxidase, LCV is oxidized by hydrogen peroxide, forming a colored crystal violet ion (CV+, which is stable for days. The LCV method uses standard equipment and allows for detection at the low microM concentration level. Results show strong pH dependence with maximum LCV oxidation at pH 4.23. By chelating dissolved Fe(II with EDTA, hydrogen peroxide can be stabilized for analysis. Results are presented for hydrogen peroxide quantification in pyrite–water slurries. Pyrite–water slurries show surface area dependent generation of hydrogen peroxide only in the presence of EDTA, which chelates dissolved Fe(II. Given the stability of CV+, this method is particularly useful for field work that involves the detection of hydrogen peroxide.

  11. Use of hydrogen peroxide-egg albumin to eliminate nonspecific staining in immunoperoxidase techniques.

    Science.gov (United States)

    Zehr, D R

    1978-05-01

    The application of hydrogen peroxide and egg albumin to paraffin sections before immunostaining prevents nonspecific staining by immunoperoxidase techniques. This method is more effective than pretreating secions with normal sera, or using either egg albumin or hydrogen peroxide separately, or using diluted antisera with prolonged incuabations in the staining procedure.

  12. Hydrogen peroxide as a new defensive compound in "benzoyl cyanide" producing polydesmid millipedes

    Science.gov (United States)

    Kuwahara, Yasumasa; Yamaguchi, Takuya; Ichiki, Yayoi; Tanabe, Tsutomu; Asano, Yasuhisa

    2017-04-01

    Hydrogen peroxide was newly and simultaneously demonstrated with well-known hydrogen cyanide as a component of defensive secretions of "benzoyl cyanide" producing polydesmid millipedes. Presence of hydrogen peroxide was successively evidenced by Trinder reagent's spray with colorless as well as oily smears of defensive secretions containing benzoyl cyanide and hydrogen cyanide by alkaline picrate paper treatment. Linear correlation was demonstrated between quantities of hydrogen peroxide and benzoyl cyanide. By qualitative assay, seven benzoyl cyanide containing polydesmidans (six species of adults and one species of a nymph at stadium I) tested positive to Trinder reagent, indicative of the presence of hydrogen peroxide (together with hydrogen cyanide), while two cyanogenic species without benzoyl cyanide exhibited negative responses to the reagent. Two types of millipedes were elucidated as species of cyanogenic Polydesmida.

  13. Gold-catalyzed oxidation of substituted phenols by hydrogen peroxide

    KAUST Repository

    Cheneviere, Yohan

    2010-10-20

    Gold nanoparticles deposited on inorganic supports are efficient catalysts for the oxidation of various substituted phenols (2,6-di-tert-butyl phenol and 2,3,6-trimethyl phenol) with aqueous hydrogen peroxide. By contrast to more conventional catalysts such as Ti-containing mesoporous silicas, which convert phenols to the corresponding benzoquinones, gold nanoparticles are very selective to biaryl compounds (3,3′,5,5′-tetra-tert-butyl diphenoquinone and 2,2′,3,3′,5,5′-hexamethyl-4,4′- biphenol, respectively). Products yields and selectivities depend on the solvent used, the best results being obtained in methanol with yields >98%. Au offers the possibility to completely change the selectivity in the oxidation of substituted phenols and opens interesting perspectives in the clean synthesis of biaryl compounds for pharmaceutical applications. © 2010 Elsevier B.V. All rights reserved.

  14. Severe acute haemorrhagic gastritis controlled by hydrogen peroxide.

    Science.gov (United States)

    Katsinelos, Panagiotis; Kountouras, Jannis; Paroutoglou, George; Beltsis, Athanasios; Mimidis, Kostas; Pilpilidis, Ioannis; Zavos, Christos

    2006-01-01

    A 92-year-old woman presented with severe acute haemorrhagic gastritis due to abuse of non-steroidal anti-inflammatory drugs (NSAIDs). She was treated with instillation of 150 ml 3% hydrogen peroxide (H2O2) every 2 h via a nasogastric tube. The copious amount of bright red blood through the nasogastric tube started to decline substantially after the first administration of H2O2 and continued to reveal clear material during the second and third instillation of H2O2. The total amount of H2O2 administered was 600 ml. No rebleeding and only a few flame-shaped intramucosal haemorrhages were observed on the following four consecutive daily endoscopic evaluations. These are promising observations which will have to be confirmed with respect to the safety and efficacy of H2O2 treatment by further controlled studies.

  15. Cerebral arterial gas embolism, ingestion of hydrogen peroxide and flight.

    Science.gov (United States)

    Joob, Beuy; Wiwanitkit, Viroj

    2017-03-01

    We read with interest the recent report by Smedley et al. on an interesting case of cerebral arterial gas embolism (CAGE) after pre-flight ingestion of hydrogen peroxide (H₂O₂). The authors discuss the safety of aero-medical transfer following H₂O₂ ingestion. We agree with the possible problems but the concern on the other side of the coin needs to be mentioned; can transfer be delayed is the big question? Indeed, as reported by others, ingestion of even a small amount of concentrated H₂O₂ can result in CAGE. Hence, whether aero-medical transfer proceeds or not, severe, life-threatening embolism can occur. Since it was reported that "complete neurologic recovery occurred quickly with hyperbaric therapy", this supports the contention that the fastest transfer of the patient for hyperbaric treatment should be the primary focus.

  16. [Determination of peracetic acid and hydrogen peroxide in a preparation].

    Science.gov (United States)

    Bodiroga, Milanka; Ognjanović, Jasminka

    2002-01-01

    Iodometric and permanganometric titrations were used for determination of peracetic acid and hydrogen peroxide (H2O2) in the mixture. Two procedures were described and compared. Titrations could be done in only one vessel, in the same reaction mixture, when iodometric titration of peracetic acid was continued after the permanganometric titration of H2O2, (procedure A). Peracetic acid and H2O2, as oxidizing agents, reacted with potassium iodide in an acid medium, evolving iodine. This reaction was used for the quantitative iodometric determination of total peroxide in procedure B. H2O2 reacted with potassium permanganate in acid medium, but peracetic acid did not react under the same conditions. That made possible the selective permanganometric determination of H2O2 in the presence of peracetic acid. The procedure B was performed in two titration vessels (KV = 3.4% for peracetic acid, 0.6% for H2O2). The procedure A for iodometric determination of peracetic acid in one titration vessel after permanganometric titration of H2O2 was recommended (KV = 2.5% for peracetic acid, 0.45% for H2O2).

  17. Growth suppression and branchitis in trout exposed to hydrogen peroxide.

    Science.gov (United States)

    Speare, D J; Carvajal, V; Horney, B S

    1999-05-01

    This study was designed to investigate the effect of single short-duration bath-treatment with hydrogen peroxide (1000, 1250 or 1500 mg/l for 20 min), as currently used in treatment for sea lice, on the growth rate and gill morphology of rainbow trout. All three dose levels significantly reduced the specific growth rate of fish (22-36% reduction) during the first 3 weeks after treatment. A significant effect on growth rate (10-11% reduction) persisted over an additional 3 weeks for the two highest doses. Gill lesions occurred at all three dose levels and also at an additional peroxide concentration of 750 mg/l; these lesions were characterized by large foci of epithelial hyperplasia in which lamellar fusion, pillar cell necrosis, and pillar channel aneurysms had developed. The proportion of damaged filaments showed a significant positive linear relationship with dose during the first 2 weeks after treatment. A significant decline in number of lesions occurred at 1000-1500 mg/l over the 3-week sampling period. During healing, necrotic lamellae were replaced by means of a pillar channel regenerative process. Copyright 1999 W.B. Saunders Company Ltd.

  18. Determination of peracetic acid and hydrogen peroxide in the mixture

    Directory of Open Access Journals (Sweden)

    Bodiroga Milanka

    2002-01-01

    Full Text Available Iodometric and permanganometric titrations were used for determination of peracetic acid and hydrogen peroxide (H2O2 in the mixture. Two procedures were described and compared. Titrations could be done in only one vessel, in the same reaction mixture, when iodometric titration of peracetic acid was continued after the permanganometric titration of H2O2, (procedure A. Peracetic acid and H2O2, as oxidizing agents, reacted with potassium iodide in an acid medium, evolving iodine. This reaction was used for the quantitative iodometric determination of total peroxide in procedure B. H2O2 reacted with potassium permanganate in acid medium, but peracetic acid did not react under the same conditions. That made possible the selective permanganometric determination of H2O2 in the presence of peracetic acid. The procedure B was performed in two titration vessels (KV=3.4% for peracetic acid, 0.6% for H2O2. The procedure A for iodometric determination of peracetic acid in one titration vessel after permanganometric titration of H2O2 was recommended (KV=2,5% for peracetic acid, 0,45% for H2O2.

  19. Efficacy of Mouthwashes Containing Hydrogen Peroxide on Tooth Whitening

    Directory of Open Access Journals (Sweden)

    Muhammet Karadas

    2015-01-01

    Full Text Available The aim of this study was to analyze the efficacy of mouthwashes containing hydrogen peroxide compared with 10% carbamide peroxide (CP gel. Fifty enamel-dentin samples were obtained from bovine incisors and then stained in a tea solution. The stained samples were randomly divided into five groups according to the whitening product applied (n=10: AS: no whitening (negative control, with the samples stored in artificial saliva; CR: Crest 3D White mouthwash; LS: Listerine Whitening mouthwash; SC: Scope White mouthwash; and OP group: 10% CP Opalescence PF (positive control. Color measurements were carried out with a spectrophotometer before staining, after staining, and on the 7th, 28th, and 56th day of the whitening period. The data were analyzed using two-way analysis of variance followed by a Tukey post hoc test. The color change (ΔE was significantly greater in all the groups compared to that of the AS group. After 56 days, no significant differences were found among the mouthwash products with respect to color change (P>0.05. The whiteness of the teeth treated with the mouthwashes increased significantly over time. Nevertheless, the color change achieved with the mouthwashes was significantly lower than that achieved with the 10% CP at-home bleaching gel.

  20. Evaluating the virucidal efficacy of hydrogen peroxide vapour.

    Science.gov (United States)

    Goyal, S M; Chander, Y; Yezli, S; Otter, J A

    2014-04-01

    Surface contamination has been implicated in the transmission of certain viruses, and surface disinfection can be an effective measure to interrupt the spread of these agents. To evaluate the in-vitro efficacy of hydrogen peroxide vapour (HPV), a vapour-phase disinfection method, for the inactivation of a number of structurally distinct viruses of importance in the healthcare, veterinary and public sectors. The viruses studied were: feline calicivirus (FCV, a norovirus surrogate); human adenovirus type 1; transmissible gastroenteritis coronavirus of pigs (TGEV, a severe acute respiratory syndrome coronavirus [SARS-CoV] surrogate); avian influenza virus (AIV); and swine influenza virus (SwIV). The viruses were dried on stainless steel discs in 20- or 40-μL aliquots and exposed to HPV produced by a Clarus L generator (Bioquell, Horsham, PA, USA) in a 0.2-m(3) environmental chamber. Three vaporized volumes of hydrogen peroxide were tested in triplicate for each virus: 25, 27 and 33 mL. No viable viruses were identified after HPV exposure at any of the vaporized volumes tested. HPV was virucidal (>4-log reduction) against FCV, adenovirus, TGEV and AIV at the lowest vaporized volume tested (25 mL). For SwIV, due to low virus titre on the control discs, >3.8-log reduction was shown for the 25-mL vaporized volume and >4-log reduction was shown for the 27-mL and 33-mL vaporized volumes. HPV was virucidal for structurally distinct viruses dried on surfaces, suggesting that HPV can be considered for the disinfection of virus-contaminated surfaces. Copyright © 2014 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  1. Depletion Rate of Hydrogen Peroxide from Sodium Perborate Bleaching Agent.

    Science.gov (United States)

    Tran, Liliann; Orth, Rebecca; Parashos, Peter; Tao, Ying; Tee, Calvin W J; Thomas, Vineet Thenalil; Towers, Georgina; Truong, Diem Thuy; Vinen, Cynthia; Reynolds, Eric C

    2017-03-01

    Internal bleaching of discolored teeth uses sodium perborate reacting with water to form the active agent, hydrogen peroxide (H2O2). Sodium perborate is replaced at varying time intervals depending on clinician preference and until esthetically acceptable results are achieved, but this is done without scientific basis. This study measured the depletion rate of hydrogen peroxide from sodium perborate as a bleaching agent. Two sodium perborate bleaching products (Odontobleach [Australian Dental Manufacturing, Kenmore Hills, Queensland, Australia] and Endosure Perborate Micro [Dentalife, Ringwood, Victoria, Australia]) and distilled deionized water mixtures at ratios of 25 μg/mL, 50 μg/mL, and 100 μg/mL were placed into sealed microtubes and incubated at 37°C. H2O2 concentrations were measured at 23 time points over 4 weeks. Quantification of H2O2 concentrations was obtained using a ferrothiocyanate oxidation reduction reaction followed by spectrophotometry readings. The H2O2 concentration rapidly peaked within 27 hours and reached a plateau by about 3 days (75 hours). Low levels of H2O2 were evident beyond 3 days and for at least 28 days. No significant differences were found between the 2 sodium perborate products. There was also no significant difference in the depletion rate between the different ratios. Based on the chemistry of H2O2 depletion, the minimum replacement interval for the bleaching agent is 3 days. Frequent replacements of the perborate clinically may be unnecessary because of the continued presence of low H2O2 levels for at least 28 days. Although these data cannot be extrapolated to the clinical situation, they set a baseline for further studies to address the many clinical variables influencing internal bleaching. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  2. Effect of hydrogen peroxide and sodium perborate on biomechanical properties of human dentin.

    Science.gov (United States)

    Chng, Hui Kheng; Palamara, Joseph E A; Messer, Harold H

    2002-02-01

    This study compared the ultimate tensile strength, micropunch shear strength, and microhardness of bleached and unbleached human dentin. Forty-four intact premolars were root canal treated and randomly divided into four groups. Bleaching agents were sealed in pulp chambers, as in clinical use. Group 1 (control) was treated with water, group 2 with 30% hydrogen peroxide, group 3 with sodium perborate mixed with water, and group 4 with sodium perborate mixed with 30% hydrogen peroxide. The teeth were stored in saline at 37 degrees C for 7 days. The teeth were then sectioned and biomechanical tests were carried out on dentin specimens that were obtained from all teeth. Intracoronal bleaching with 30% hydrogen peroxide and sodium perborate used either alone or in combination weakened dentin. Hydrogen peroxide alone tended to be more damaging than sodium perborate used alone or sodium perborate mixed with hydrogen peroxide.

  3. Chemiluminescent nanomicelles for imaging hydrogen peroxide and self-therapy in photodynamic therapy.

    Science.gov (United States)

    Chen, Rui; Zhang, Luzhong; Gao, Jian; Wu, Wei; Hu, Yong; Jiang, Xiqun

    2011-01-01

    Hydrogen peroxide is a signal molecule of the tumor, and its overproduction makes a higher concentration in tumor tissue compared to normal tissue. Based on the fact that peroxalates can make chemiluminescence with a high efficiency in the presence of hydrogen peroxide, we developed nanomicelles composed of peroxalate ester oligomers and fluorescent dyes, called peroxalate nanomicelles (POMs), which could image hydrogen peroxide with high sensitivity and stability. The potential application of the POMs in photodynamic therapy (PDT) for cancer was also investigated. It was found that the PDT-drug-loaded POMs were sensitive to hydrogen peroxide, and the PDT drug could be stimulated by the chemiluminescence from the reaction between POMs and hydrogen peroxide, which carried on a self-therapy of the tumor without the additional laser light resource.

  4. Hyperbaric oxygen therapy for systemic gas embolism after hydrogen peroxide ingestion.

    Science.gov (United States)

    Byrne, Brendan; Sherwin, Robert; Courage, Cheryl; Baylor, Alfred; Dolcourt, Bram; Brudzewski, Jacek R; Mosteller, Jeffrey; Wilson, Robert F

    2014-02-01

    Hydrogen peroxide is a commonly available product and its ingestion has been demonstrated to produce in vivo gas bubbles, which can embolize to devastating effect. We report two cases of hydrogen peroxide ingestion with resultant gas embolization, one to the portal system and one cerebral embolus, which were successfully treated with hyperbaric oxygen therapy (HBO), and review the literature. Two individuals presented to our center after unintentional ingestion of concentrated hydrogen peroxide solutions. Symptoms were consistent with portal gas emboli (Patient A) and cerebral gas emboli (Patient B), which were demonstrated on imaging. They were successfully treated with HBO and recovered without event. As demonstrated by both our experience as well as the current literature, HBO has been used to successfully treat gas emboli associated with hydrogen peroxide ingestion. We recommend consideration of HBO in any cases of significant hydrogen peroxide ingestion with a clinical picture compatible with gas emboli. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Spatial and temporal variations and factors controlling the concentrations of hydrogen peroxide and organic peroxides in rivers

    OpenAIRE

    Mostofa, Khan M. G.; Sakugawa, Hiroshi

    2009-01-01

    Hydrogen peroxide (H2O2) and organic peroxides (ROOH) were examined in water samples collected from the upstream and downstream sites of two Japanese rivers (the Kurose and the Ohta). H2O2 concentrations during monthly measurements varied between 6 and 213nM in the Kurose River and 33 and 188nM in the Ohta River. ROOH varied between 0 and 73nM in the Kurose River and 1 and 80nM in the Ohta. Concentrations of peroxides were higher during the summer months than in winter. H2O2 concentrations co...

  6. Investigation of a novel electrocatalyst for hydrogen peroxide reduction and its application to sensing and biosensing.

    OpenAIRE

    Gonzalez-Macia, Laura

    2011-01-01

    Hydrogen peroxide has, for many years, been shown to be a very important compound due to its wide and varied applications in many industrial processes as well as biological systems. Therefore, its detection and measurement represents an important analytical issue. Traditional methods such as titrimetry or spectrophotometry have more recently been displaced by electrochemical techniques, which have proven to be an inexpensive and effective means of hydrogen peroxide determination. Hydrogen ...

  7. Evaluation of Extraradicular Diffusion of Hydrogen Peroxide during Intracoronal Bleaching Using Different Bleaching Agents.

    Science.gov (United States)

    Rokaya, Mohammad E; Beshr, Khaled; Hashem Mahram, Abeer; Samir Pedir, Samah; Baroudi, Kusai

    2015-01-01

    Objectives. Extra radicular diffusion of hydrogen peroxide associated with intracoronal teeth bleaching was evaluated. Methods. 108 intact single rooted extracted mandibular first premolars teeth were selected. The teeth were instrumented with WaveOne system and obturated with gutta percha and divided into four groups (n = 27) according to the bleaching materials used. Each main group was divided into three subgroups (n = 9) according to the time of extra radicular hydrogen peroxide diffusion measurements at 1, 7, and 14 days: group 1 (35% hydrogen peroxide), group 2 (35% carbamide peroxide), group 3 (sodium perborate-30% hydrogen peroxide mixture), and group 4 (sodium perborate-water mixture). Four cemental dentinal defects were prepared just below the CEJ on each root surface. The amount of hydrogen peroxide that leached out was evaluated after 1, 7, and 14 days by spectrophotometer analysis. The results were analyzed using the ANOVA and Tukey's test. Results. Group 1 showed highest extra radicular diffusion, followed by group 3 and group 2, while group 4 showed the lowest mean extra radicular diffusion. Conclusion. Carbamide peroxide and sodium perborate-water mixture are the most suitable bleaching materials used for internal bleaching due to their low extra radicular diffusion of hydrogen peroxide.

  8. Evaluation of Extraradicular Diffusion of Hydrogen Peroxide during Intracoronal Bleaching Using Different Bleaching Agents

    Directory of Open Access Journals (Sweden)

    Mohammad E. Rokaya

    2015-01-01

    Full Text Available Objectives. Extra radicular diffusion of hydrogen peroxide associated with intracoronal teeth bleaching was evaluated. Methods. 108 intact single rooted extracted mandibular first premolars teeth were selected. The teeth were instrumented with WaveOne system and obturated with gutta percha and divided into four groups (n=27 according to the bleaching materials used. Each main group was divided into three subgroups (n=9 according to the time of extra radicular hydrogen peroxide diffusion measurements at 1, 7, and 14 days: group 1 (35% hydrogen peroxide, group 2 (35% carbamide peroxide, group 3 (sodium perborate-30% hydrogen peroxide mixture, and group 4 (sodium perborate-water mixture. Four cemental dentinal defects were prepared just below the CEJ on each root surface. The amount of hydrogen peroxide that leached out was evaluated after 1, 7, and 14 days by spectrophotometer analysis. The results were analyzed using the ANOVA and Tukey’s test. Results. Group 1 showed highest extra radicular diffusion, followed by group 3 and group 2, while group 4 showed the lowest mean extra radicular diffusion. Conclusion. Carbamide peroxide and sodium perborate-water mixture are the most suitable bleaching materials used for internal bleaching due to their low extra radicular diffusion of hydrogen peroxide.

  9. Fibrous Catalyst-Enhanced Acanthamoeba Disinfection by Hydrogen Peroxide.

    Science.gov (United States)

    Kilvington, Simon; Winterton, Lynn

    2017-11-01

    Hydrogen peroxide (H2O2) disinfection systems are contact-lens-patient problem solvers. The current one-step, criterion-standard version has been widely used since the mid-1980s, without any significant improvement. This work identifies a potential next-generation, one-step H2O2, not based on the solution formulation but rather on a case-based peroxide catalyst. One-step H2O2 systems are widely used for contact lens disinfection. However, antimicrobial efficacy can be limited because of the rapid neutralization of the peroxide from the catalytic component of the systems. We studied whether the addition of an iron-containing catalyst bound to a nonfunctional propylene:polyacryonitrile fabric matrix could enhance the antimicrobial efficacy of these one-step H2O2 systems. Bausch + Lomb PeroxiClear and AOSept Plus (both based on 3% H2O2 with a platinum-neutralizing disc) were the test systems. These were tested with and without the presence of the catalyst fabric using Acanthamoeba cysts as the challenge organism. After 6 hours' disinfection, the number of viable cysts was determined. In other studies, the experiments were also conducted with biofilm formed by Stenotrophomonas maltophilia and Elizabethkingia meningoseptica bacteria. Both control systems gave approximately 1-log10 kill of Acanthamoeba cysts compared with 3.0-log10 kill in the presence of the catalyst (P catalyst compared with ≥3.0-log10 kill when it was omitted. In 30 rounds' recurrent usage, the experiments, in which the AOSept Plus system was subjected to 30 rounds of H2O2 neutralization with or without the presence of catalytic fabric, showed no loss in enhanced biocidal efficacy of the material. The catalytic fabric was also shown to not retard or increase the rate of H2O2 neutralization. We have demonstrated the catalyst significantly increases the efficacy of one-step H2O2 disinfection systems using highly resistant Acanthamoeba cysts and bacterial biofilm. Incorporating the catalyst into the

  10. Hydrogen peroxide in exhaled breath condensate: A clinical study

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    C Nagaraja

    2012-01-01

    Full Text Available Objectives: To study the ongoing inflammatory process of lung in healthy individuals with risk factors and comparing with that of a known diseased condition. To study the inflammatory response to treatment. Background: Morbidity and mortality of respiratory diseases are raising in trend due to increased smokers, urbanization and air pollution, the diagnosis of these conditions during early stage and management can improve patient′s lifestyle and morbidity. Materials and Methods: One hundred subjects were studied from July 2010 to September 2010; the level of hydrogen peroxide concentration in exhaled breath condensate was measured using Ecocheck. Results: Of the 100 subjects studied, 23 were healthy individuals with risk factors (smoking, exposure to air pollution, and urbanization; the values of hydrogen peroxide in smokers were 200-2220 nmol/l and in non-smokers 340-760 nmol/l. In people residing in rural areas values were 20-140 nmol/l in non-smokers and 180 nmol/l in smokers. In chronic obstructive pulmonary disease cases, during acute exacerbations values were 540-3040 nmol/l and 240-480 nmol/l following treatment. In acute exacerbations of bronchial asthma, values were 400-1140 nmol/l and 100-320 nmol/l following treatment. In cases of bronchiectasis, values were 300-340 nmol/l and 200-280 nmol/l following treatment. In diagnosed pneumonia cases values were 1060-11800 nmol/l and 540-700 nmol/l following treatment. In interstitial lung diseases, values ranged from 220-720 nmol/l and 210-510 nmol/l following treatment. Conclusion: Exhaled breath condensate provides a non-invasive means of sampling the lower respiratory tract. Collection of exhaled breath condensate might be useful to detect the oxidative destruction of the lung as well as early inflammation of the airways in a healthy individual with risk factors and comparing the inflammatory response to treatment.

  11. Crystal structure of peroxiredoxin from Aeropyrum pernix K1 complexed with its substrate, hydrogen peroxide.

    Science.gov (United States)

    Nakamura, Tsutomu; Kado, Yuji; Yamaguchi, Takafumi; Matsumura, Hiroyoshi; Ishikawa, Kazuhiko; Inoue, Tsuyoshi

    2010-01-01

    Peroxiredoxin (Prx) reduces hydrogen peroxide and alkyl peroxides to water and corresponding alcohols, respectively. The reaction is dependent on a peroxidatic cysteine, whose sulphur atom nucleophilically attacks one of the oxygen atoms of the peroxide substrate. In spite of the many structural studies that have been carried out on this reaction, the tertiary structure of the hydrogen peroxide-bound form of Prx has not been elucidated. In this paper, we report the crystal structure of Prx from Aeropyrum pernix K1 in the peroxide-bound form. The conformation of the polypeptide chain is the same as that in the reduced apo-form. The hydrogen peroxide molecule is in close contact with the peroxidatic Cys50 and the neighbouring Thr47 and Arg126 side chain atoms, as well as with the main chain nitrogen atoms of Val49 and Cys50. Bound peroxide was also observed in the mutant C50S, in which the peroxidatic cysteine was replaced by serine. Therefore, the sulphur atom of the peroxidatic cysteine is not essential for peroxide binding, although it enhances the binding affinity. Hydrogen peroxide binds to the protein so that it fills the active site pocket. This study provides insight into the early stage of the Prx reaction.

  12. Possibilities and Challenges for Quantitative Optical Sensing of Hydrogen Peroxide

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    Maria Moßhammer

    2017-10-01

    Full Text Available Hydrogen peroxide (H2O2 plays a key role in many biological processes spanning from coral bleaching, over cell signaling to aging. However, exact quantitative assessments of concentrations and dynamics of H2O2 remain challenging due to methodological limitations—especially at very low (sub μM concentrations. Most published optical detection schemes for H2O2 suffer from irreversibility, cross sensitivity to other analytes such as other reactive oxygen species (ROS or pH, instability, temperature dependency or limitation to a specific medium. We review optical detection schemes for H2O2, compare their specific advantages and disadvantages, and discuss current challenges and new approaches for quantitative optical H2O2 detection, with a special focus on luminescence-based measurements. We also review published concentration ranges for H2O2 in natural habitats, and physiological concentrations in different biological samples to provide guidelines for future experiments and sensor development in biomedical and environmental science.

  13. Rotovibrational spectroscopy of hydrogen peroxide embedded in superfluid helium nanodroplets.

    Science.gov (United States)

    Raston, Paul L; Knapp, Chrissy J; Jäger, Wolfgang

    2011-11-14

    We report the infrared depletion spectrum of para- and ortho-hydrogen peroxide embedded in superfluid helium nanodroplets in the OH stretching region. Six transitions were observed in the antisymmetric stretching band (v(5)) of H(2)O(2), and three in the weaker symmetric stretching band (v(1)). While rotations about the b- and c-axes are slowed by a factor of ∼0.4 relative to the gas phase, rotations about the a-axis are not significantly affected; this relates to the rotational speed about the a-axis being too fast for helium density to adiabatically follow. The trans tunneling splitting does not appear to be considerably affected by the helium droplet environment, and is reduced by only 6% relative to the gas phase, under the assumption that the vibrational shifts of the v(5) and v(1) torsional subbands are the same. The linewidths increase with increasing rotorsional energies, and are significantly narrower for energies which fall within the "phonon gap" of superfluid helium. These narrower lines are asymmetrically broadened, indicative of a dynamical coupling between the H(2)O(2) rotor and surrounding helium density.

  14. Hydrogen peroxide produced by oral Streptococci induces macrophage cell death.

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    Nobuo Okahashi

    Full Text Available Hydrogen peroxide (H2O2 produced by members of the mitis group of oral streptococci plays important roles in microbial communities such as oral biofilms. Although the cytotoxicity of H2O2 has been widely recognized, the effects of H2O2 produced by oral streptococci on host defense systems remain unknown. In the present study, we investigated the effect of H2O2 produced by Streptococcus oralis on human macrophage cell death. Infection by S. oralis was found to stimulate cell death of a THP-1 human macrophage cell line at multiplicities of infection greater than 100. Catalase, an enzyme that catalyzes the decomposition of H2O2, inhibited the cytotoxic effect of S. oralis. S. oralis deletion mutants lacking the spxB gene, which encodes pyruvate oxidase, and are therefore deficient in H2O2 production, showed reduced cytotoxicity toward THP-1 macrophages. Furthermore, H2O2 alone was capable of inducing cell death. The cytotoxic effect seemed to be independent of inflammatory responses, because H2O2 was not a potent stimulator of tumor necrosis factor-α production in macrophages. These results indicate that streptococcal H2O2 plays a role as a cytotoxin, and is implicated in the cell death of infected human macrophages.

  15. Space hardware compatibility tests with hydrogen peroxide gas plasma sterilization

    Science.gov (United States)

    Faye, Delphine; Aguila, Alexandre; Debus, Andre; Remaury, Stephanie; Nabarra, Pascale; Darbord, Jacques C.; Soufflet, Caroline; Destrez, Philippe; Coll, Patrice; Coscia, David

    The exploration of the Solar System shall comply with planetary protection requirements handled presently by the Committee of Space Research (COSPAR). The goal of planetary protection is to protect celestial bodies from terrestrial contamination and also to protect the Earth environment from an eventual contamination carried by return samples or by space systems. For project teams, avoiding the biological contamination of other Solar System bodies such as Mars imposes to perform unusual tasks at technical and operational constraints point of view. The main are the reduction of bioburden on space hardware, the sterile integration of landers, the control of the biological cleanliness and the limitation of crash probability. In order to reduce the bioburden on spacecraft, the use of qualified sterilization processes may be envisaged. Since 1992 now, with the Mars96 mission, one of the most often used is the Sterrad(R) process working with hydrogen peroxide gas plasma. In the view of future Mars exploration programs, after tests performed in the frame of previous missions, a new test campaign has been performed on thermal coatings and miscellaneous materials coming from an experiment in order to assess the compatibility of space hardware and material with this sterilization process.

  16. Salidroside inhibits endogenous hydrogen peroxide induced cytotoxicity of endothelial cells.

    Science.gov (United States)

    Zhao, Xingyu; Jin, Lianhai; Shen, Nan; Xu, Bin; Zhang, Wei; Zhu, Hongli; Luo, Zhengli

    2013-01-01

    Salidroside, a phenylpropanoid glycoside isolated from Rhodiola rosea L., shows potent antioxidant property. Herein, we investigated the protective effects of salidroside against hydrogen peroxide (H2O2)-induced oxidative damage in human endothelial cells (EVC-304). EVC-304 cells were incubated in the presence or absence of low steady states of H2O2 (3-4 µM) generated by glucose oxidase (GOX) with or without salidroside. 3(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione (GSH) assays were performed, together with Hoechst 33258 staining and flow cytometric analysis using Annexin-V and propidium iodide (PI) label. The results indicated that salidroside pretreatment attenuated endogenous H2O2 induced apoptotic cell death in EVC-304 cells in a dose-dependent pattern. Furthermore, Western blot data revealed that salidroside inhibited activation of caspase-3, 9 and cleavage of poly(ADP-ribose) polymerase (PARP) induced by endogenous H2O2. It also decreased the expression of Bax and rescued the balance of pro- and anti-apoptotic proteins. All these results demonstrated that salidroside may present a potential therapy for oxidative stress in cardiovascular and cerebrovascular diseases.

  17. Hydrogen peroxide sensing based on carbon quantum dots

    Directory of Open Access Journals (Sweden)

    Chu Cheng-Shane

    2016-01-01

    Full Text Available In this work, carbon quantum dots (CQDs have been synthesized by one step hydrothermal method to detect hydrogen peroxide (H2O2. The optical H2O2 sensors were based on the fluorescent quenching of the carbon quantum dots. The optical H2O2 sensors demonstrate capable of detecting H2O2 over the range of 0-88.2 mM and 0-60 mM. The H2O2 sensitivities of wavelength shift to changes in the H2O2 concentration were found to be 0.18 nm/mM and 0.26 nm/mM. These results of the optical sensors showed that the method can be used in practice detection of H2O2 and could offer a new approach for developing a new optical biosensor. The CQDs exhibit good emission property and high stability, as well as excitation-independent emission behavior. Moreover, it is attractive that CQDs can be used as an effective fluorescent probe for the detection of H2O2 with linear Stern-Volmer plot and wavelength shift in an aqueous solution.

  18. Necessity of OxyR for the hydrogen peroxide stress response and full virulence in Ralstonia solanacearum.

    Science.gov (United States)

    Flores-Cruz, Zomary; Allen, Caitilyn

    2011-09-01

    The plant pathogen Ralstonia solanacearum, which causes bacterial wilt disease, is exposed to reactive oxygen species (ROS) during tomato infection and expresses diverse oxidative stress response (OSR) genes during midstage disease on tomato. The R. solanacearum genome predicts that the bacterium produces multiple and redundant ROS-scavenging enzymes but only one known oxidative stress response regulator, OxyR. An R. solanacearum oxyR mutant had no detectable catalase activity, did not grow in the presence of 250 μM hydrogen peroxide, and grew poorly in the oxidative environment of solid rich media. This phenotype was rescued by the addition of exogenous catalase, suggesting that oxyR is essential for the hydrogen peroxide stress response. Unexpectedly, the oxyR mutant strain grew better than the wild type in the presence of the superoxide generator paraquat. Gene expression studies indicated that katE, kaG, ahpC1, grxC, and oxyR itself were each differentially expressed in the oxyR mutant background and in response to hydrogen peroxide, suggesting that oxyR is necessary for hydrogen peroxide-inducible gene expression. Additional OSR genes were differentially regulated in response to hydrogen peroxide alone. The virulence of the oxyR mutant strain was significantly reduced in both tomato and tobacco host plants, demonstrating that R. solanacearum is exposed to inhibitory concentrations of ROS in planta and that OxyR-mediated responses to ROS during plant pathogenesis are important for R. solanacearum host adaptation and virulence.

  19. Determination of hydrogen peroxide in workplace air: interferences and method validation.

    Science.gov (United States)

    Christensen, C S; Brødsgaard, S; Mortensen, P; Egmose, K; Linde, A

    2000-08-01

    A dynamic system for the generation of stable hydrogen peroxide test atmospheres was applied to the evaluation of samplers used for the determination of hydrogen peroxide in workplace air. The system is able to generate gas mixtures of between 0.1 and 10 ppm at different combinations of relative humidity (20-80%) and temperature (10-30 degrees C). Gaseous hydrogen peroxide is sampled on glass filters impregnated with Ti(IV) chloride and sulfuric acid and analyzed by UV spectroscopy. An interference was observed due to the acid catalyzed decomposition of peroxyacetic acid to hydrogen peroxide. This was significantly reduced by applying high sample flow rates and by lowering the concentration of sulfuric acid. The performance of the sampler and sources of uncertainties were tested according to the European Standard EN 1076.

  20. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT: BIOQUELL, INC. CLARIS C HYDROGEN PEROXIDE GAS GENERATOR

    Science.gov (United States)

    The Environmental Technology Verification report discusses the technology and performance of the Clarus C Hydrogen Peroxide Gas Generator, a biological decontamination device manufactured by BIOQUELL, Inc. The unit was tested by evaluating its ability to decontaminate seven types...

  1. Structural and spectroscopic ellipsometry characterization for electrodeposited ZnO growth at different hydrogen peroxide concentration

    Energy Technology Data Exchange (ETDEWEB)

    El Hichou, A., E-mail: elhichou@fstg-marrakech.ac.m [Laboratoire de la Matiere Condensee et Nanostructures (LMCN), Faculte des Sciences et Techniques, BP 549, 40000 Marrakech (Morocco); Stein, N.; Boulanger, C. [Institut Jean Lamour, Laboratoire d' Electrochimie des Materiaux, UPV-M, CNRS, 1 bd Arago CP 87811, 57078 Metz cedex 3 (France); Johann, L. [Laboratoire de Physique des Milieux denses, UPV-M, 1 bd Arago CP 87811, 57078 Metz cedex 3 (France)

    2010-05-31

    This work deals with textural and optical characterization of zinc oxide (ZnO) layers obtained by potentiostatic electroplating at various hydrogen peroxide concentrations (from 0 up to 5 mM). The electrodeposition process was studied by cyclic voltametry and chronoamperometry. The [002] preferred growth orientation of hexagonal phase is obtained for the lowest hydrogen peroxide concentration (1 mM), while additionally X-ray diffraction peaks are observed for hydrogen peroxide concentration ranging from 3 to 5 mM. The optical constants and the thickness of films were determined by spectroscopic ellipsometry measurements. The refractive index of all thin films shows normal dispersion behavior. It was also found that refractive index values decrease with increasing hydrogen peroxide concentration. Further, it was revealed that the changes in the optical properties are correlated to the changes in the surface structure.

  2. Hydrogen Peroxide Toxicity Induces Ras Signaling in Human Neuroblastoma SH-SY5Y Cultured Cells

    Directory of Open Access Journals (Sweden)

    Jirapa Chetsawang

    2010-01-01

    Full Text Available It has been reported that overproduction of reactive oxygen species occurs after brain injury and mediates neuronal cells degeneration. In the present study, we examined the role of Ras signaling on hydrogen peroxide-induced neuronal cells degeneration in dopaminergic neuroblastoma SH-SY5Y cells. Hydrogen peroxide significantly reduced cell viability in SH-SY5Y cultured cells. An inhibitor of the enzyme that catalyzes the farnesylation of Ras proteins, FTI-277, and a competitive inhibitor of GTP-binding proteins, GDP-beta-S significantly decreased hydrogen peroxide-induced reduction in cell viability in SH-SY5Y cultured cells. The results of this study might indicate that a Ras-dependent signaling pathway plays a role in hydrogen peroxide-induced toxicity in neuronal cells.

  3. Disproportionation of hydrogen peroxide in the presence of coordination compounds of manganese (II) with glycine

    Energy Technology Data Exchange (ETDEWEB)

    Batyr, D.G.; Isak, V.G.; Kil' mininov, S.V.

    1988-01-01

    It has been established that the effective decomposition of hydrogen peroxide takes place in the presence of coordination compounds of manganese (II) with glycine (Gly). The catalytically active species is the complex (MnGly/sub 3/)/sup 2 +/.

  4. Effect of Exogenous Application of Hydrogen Peroxide on Drought Tolerance of Glob Amaranth (Gomphrena globosa L.

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    M Goldani

    2012-12-01

    Full Text Available Drought is one of the important environmental stresses that reduce the crop growth. Oxidative stress is a secondary stress due to drought and other abiotic stresses. In order to study the effect of exogenous application of hydrogen peroxide on drought tolerance of glob amaranth (Gomphrena globosa L., an experiment was conducted in greenhouse conditions. This study was designed as factorial based on completely randomized design with 3 replications. Different concentrations of hydrogen peroxide (0, 2.5 and 5 mM and three levels of irrigation intervals (after 4, 7 and 10 days were treated in this study. The results showed that foliar application of hydrogen peroxide can improve shoot and root dry weight and alleviate adverse effects of drought stress. With increasing drought stress stomatal conductance, flower number, total chlorophyll and root volume decreased significantly. So that the lowest of these characterestics was in the irrigation after 10 days. Interaction effects of drought and hydrogen peroxide in shoot dry weight was significantly different in 5% level and in electrolyte leakage, relative water content, free proline and total root length was significantly different in 1% level. In control (4 day irrigation interval with increasing hydrogen peroxide of 2.5 mM, shoot dry weight and total root length increased 20% and 91%, respectively. In control, with increasing hydrogen peroxide to 5 mM total chlorophyll was increased 30.8% compared to 0 mM hydrogen peroxide application (control. The final result showed that foliar application of hydrogen peroxide decreased the adverse effects of drought stress.

  5. Cerebral arterial gas embolism after pre-flight ingestion of hydrogen peroxide.

    Science.gov (United States)

    Smedley, Ben L; Gault, Alan; Gawthrope, Ian C

    2016-06-01

    Cerebral arterial gas embolism (CAGE) is a feared complication of ambient depressurisation and can also be a complication of hydrogen peroxide ingestion. We present an unusual case of CAGE in a 57-year-old woman exposed to both of these risk factors. We describe her subsequent successful treatment with hyperbaric oxygen, despite a 72-hour delay in initial presentation and diagnosis, and discuss the safety of aero-medical transfer following hydrogen peroxide ingestions.

  6. Inactivation of animal and human prions by hydrogen peroxide gas plasma sterilization.

    Science.gov (United States)

    Rogez-Kreuz, C; Yousfi, R; Soufflet, C; Quadrio, I; Yan, Z-X; Huyot, V; Aubenque, C; Destrez, P; Roth, K; Roberts, C; Favero, M; Clayette, P

    2009-08-01

    Prions cause various transmissible spongiform encephalopathies. They are highly resistant to the chemical and physical decontamination and sterilization procedures routinely used in healthcare facilities. The decontamination procedures recommended for the inactivation of prions are often incompatible with the materials used in medical devices. In this study, we evaluated the use of low-temperature hydrogen peroxide gas plasma sterilization systems and other instrument-processing procedures for inactivating human and animal prions. We provide new data concerning the efficacy of hydrogen peroxide against prions from in vitro or in vivo tests, focusing on the following: the efficiency of hydrogen peroxide sterilization and possible interactions with enzymatic or alkaline detergents, differences in the efficiency of this treatment against different prion strains, and the influence of contaminating lipids. We found that gaseous hydrogen peroxide decreased the infectivity of prions and/or the level of the protease-resistant form of the prion protein on different surface materials. However, the efficiency of this treatment depended strongly on the concentration of hydrogen peroxide and the delivery system used in medical devices, because these effects were more pronounced for the new generation of Sterrad technology. The Sterrad NX sterilizer is 100% efficient (0% transmission and no protease-resistant form of the prion protein signal detected on the surface of the material for the mouse-adapted bovine spongiform encephalopathy 6PB1 strain and a variant Creutzfeldt-Jakob disease strain). Thus, gaseous or vaporized hydrogen peroxide efficiently inactivates prions on the surfaces of medical devices.

  7. Hydrogen peroxide induce modifications of human extracellular superoxide dismutase that results in enzyme inhibition

    Directory of Open Access Journals (Sweden)

    Randi H. Gottfredsen

    2013-01-01

    Full Text Available Superoxide dismutase (EC-SOD controls the level of superoxide in the extracellular space by catalyzing the dismutation of superoxide into hydrogen peroxide and molecular oxygen. In addition, the enzyme reacts with hydrogen peroxide in a peroxidase reaction which is known to disrupt enzymatic activity. Here, we show that the peroxidase reaction supports a site-specific bond cleavage. Analyses by peptide mapping and mass spectrometry shows that oxidation of Pro112 supports the cleavage of the Pro112–His113 peptide bond. Substitution of Ala for Pro112 did not inhibit fragmentation, indicating that the oxidative fragmentation at this position is dictated by spatial organization and not by side-chain specificity. The major part of EC-SOD inhibited by the peroxidase reaction was not fragmented but found to encompass oxidations of histidine residues involved in the coordination of copper (His98 and His163. These oxidations are likely to support the dissociation of copper from the active site and thus loss of enzymatic activity. Homologous modifications have also been described for the intracellular isozyme, Cu/Zn-SOD, reflecting the almost identical structures of the active site within these enzymes. We speculate that the inactivation of EC-SOD by peroxidase activity plays a role in regulating SOD activity in vivo, as even low levels of superoxide will allow for the peroxidase reaction to occur.

  8. High-performance liquid chromatography method for the determination of hydrogen peroxide present or released in teeth bleaching kits and hair cosmetic products.

    Science.gov (United States)

    Gimeno, Pascal; Bousquet, Claudine; Lassu, Nelly; Maggio, Annie-Françoise; Civade, Corinne; Brenier, Charlotte; Lempereur, Laurent

    2015-03-25

    This manuscript presents an HPLC/UV method for the determination of hydrogen peroxide present or released in teeth bleaching products and hair products. The method is based on an oxidation of triphenylphosphine into triphenylphosphine oxide by hydrogen peroxide. Triphenylphosphine oxide formed is quantified by HPLC/UV. Validation data were obtained using the ISO 12787 standard approach, particularly adapted when it is not possible to make reconstituted sample matrices. For comparative purpose, hydrogen peroxide was also determined using ceric sulfate titrimetry for both types of products. For hair products, a cross validation of both ceric titrimetric method and HPLC/UV method using the cosmetic 82/434/EEC directive (official iodometric titration method) was performed. Results obtained for 6 commercialized teeth whitening products and 5 hair products point out similar hydrogen peroxide contain using either the HPLC/UV method or ceric sulfate titrimetric method. For hair products, results were similar to the hydrogen peroxide content using the cosmetic 82/434/EEC directive method and for the HPLC/UV method, mean recoveries obtained on spiked samples, using the ISO 12787 standard, ranges from 100% to 110% with a RSD<3.0%. To assess the analytical method proposed, the HPLC method was used to control 35 teeth bleaching products during a market survey and highlight for 5 products, hydrogen peroxide contents higher than the regulated limit. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Modular Advanced Oxidation Process Enabled by Cathodic Hydrogen Peroxide Production

    Science.gov (United States)

    2015-01-01

    Hydrogen peroxide (H2O2) is frequently used in combination with ultraviolet (UV) light to treat trace organic contaminants in advanced oxidation processes (AOPs). In small-scale applications, such as wellhead and point-of-entry water treatment systems, the need to maintain a stock solution of concentrated H2O2 increases the operational cost and complicates the operation of AOPs. To avoid the need for replenishing a stock solution of H2O2, a gas diffusion electrode was used to generate low concentrations of H2O2 directly in the water prior to its exposure to UV light. Following the AOP, the solution was passed through an anodic chamber to lower the solution pH and remove the residual H2O2. The effectiveness of the technology was evaluated using a suite of trace contaminants that spanned a range of reactivity with UV light and hydroxyl radical (HO•) in three different types of source waters (i.e., simulated groundwater, simulated surface water, and municipal wastewater effluent) as well as a sodium chloride solution. Irrespective of the source water, the system produced enough H2O2 to treat up to 120 L water d–1. The extent of transformation of trace organic contaminants was affected by the current density and the concentrations of HO• scavengers in the source water. The electrical energy per order (EEO) ranged from 1 to 3 kWh m–3, with the UV lamp accounting for most of the energy consumption. The gas diffusion electrode exhibited high efficiency for H2O2 production over extended periods and did not show a diminution in performance in any of the matrices. PMID:26039560

  10. Salinity-gradient energy driven microbial electrosynthesis of hydrogen peroxide

    Science.gov (United States)

    Li, Xiaohu; Angelidaki, Irini; Zhang, Yifeng

    2017-02-01

    Hydrogen peroxide (H2O2) as a strong oxidant, is widely used in various chemical industries and environmental remediation processes. In this study, we developed an innovative method for cost-effective production of H2O2 by using a microbial reverse-electrodialysis electrolysis cell (MREC). In the MREC, electrical potential generated by the exoelectrogens and the salinity-gradient between salt and fresh water were utilized to drive the high-rate H2O2 production. Operational parameters such as air flow rate, pH, cathodic potential, flow rate of salt and fresh water were investigated. The optimal H2O2 production was observed at salt and fresh water flow rate of 0.5 mL min-1, air flow rate of 12-20 mL min-1, cathode potential of -0.485 ± 0.025 V (vs Ag/AgCl). The maximum H2O2 accumulated concentration of 778 ± 11 mg L-1 was obtained at corresponding production rate of 11.5 ± 0.5 mg L-1 h-1. The overall energy input for the synthesis process was 0.45 ± 0.03 kWh kg-1 H2O2. Cathode potential was the key factor for H2O2 production, which was mainly affected by the air flow rate. This work for the first time proved the potential of MREC as an efficient platform technology for simultaneous electrosynthesis of valuable chemicals and utilization of salinity-gradient energy.

  11. Considerations for Storage of High Test Hydrogen Peroxide (HTP) Utilizing Non-Metal Containers

    Science.gov (United States)

    Moore, Robin E.; Scott, Joseph P.; Wise, Harry

    2005-01-01

    When working with high concentrations of hydrogen peroxide, it is critical that the storage container be constructed of the proper materials, those which will not degrade to the extent that container breakdown or dangerous decomposition occurs. It has been suggested that the only materials that will safely contain the peroxide for a significant period of time are metals of stainless steel construction or aluminum use as High Test Hydrogen Peroxide (HTP) Containers. The stability and decomposition of HTP will be also discussed as well as various means suggested in the literature to minimize these problems. The dangers of excess oxygen generation are also touched upon.

  12. Direct synthesis of hydrogen peroxide using in-situ selective layer

    Science.gov (United States)

    Makertihartha, I. G. B. N.; Dharmawijaya, P. T.; Zunita, M.; Wenten, I. G.

    2017-05-01

    Hydrogen peroxide is used in broad range of application such as oxidation, bleaching, and wastewater treatment. Conventionally, hydrogen peroxide is synthesized using reduction oxidation cycle of anthraquinones from hydrogen and oxygen. This process is rather complex and requires considerable amount of energy. Direct synthesis of hydrogen peroxide is one attractive approach to said problems. However, activity and selectivity is the main problem of direct synthesis since the reactants form explosive mixture. Dilution of gasses is commonly used to solve said problem but limit the amount of reactants in the liquid solvent. Membrane reactor can separate pure reactant gases and also constantly feed them over the length of reaction channel. Pd-Ag alloy membrane can be used both as a catalyst and hydrogen dosage. There are some studies that investigate the use of Pd based membrane reactor but still no commercial application. This paper will bring basic concept of Pd based membrane reactor for direct synthesis of hydrogen peroxide. Special attention will be given to current hurdles and their possible solutions that lead to facile production of hydrogen peroxide. Furthermore, recent trends towards utilization of micro reactor will also be discussed.

  13. Reduction of hydrogen peroxide-induced erythrocyte damage by Carica papaya leaf extract.

    Science.gov (United States)

    Okoko, Tebekeme; Ere, Diepreye

    2012-06-01

    To investigate the in vitro antioxidant potential of Carica papaya (C. papaya) leaf extract and its effect on hydrogen peroxide-induced erythrocyte damage assessed by haemolysis and lipid peroxidation. Hydroxyl radical scavenging activities, hydrogen ion scavenging activity, metal chelating activity, and the ferrous ion reducing ability were assessed as antioxidant indices. In the other experiment, human erythrocytes were treated with hydrogen peroxide to induce erythrocyte damage. The extract (at various concentrations) was subsequently incubated with the erythrocytes and later analysed for haemolysis and lipid peroxidation as indices for erythrocyte damage. Preliminary investigation of the extract showed that the leaf possessed significant antioxidant and free radical scavenging abilities using in vitro models in a concentration dependent manner (Ppapaya leaves possess significant bioactive potential which is attributed to the phytochemicals which act in synergy. Thus, the leaves can be exploited for pharmaceutical and nutritional purposes.

  14. Efficiency of hydrogen peroxide in improving disinfection of ICU rooms.

    Science.gov (United States)

    Blazejewski, Caroline; Wallet, Frédéric; Rouzé, Anahita; Le Guern, Rémi; Ponthieux, Sylvie; Salleron, Julia; Nseir, Saad

    2015-02-02

    The primary objective of this study was to determine the efficiency of hydrogen peroxide (H₂O₂) techniques in disinfection of ICU rooms contaminated with multidrug-resistant organisms (MDRO) after patient discharge. Secondary objectives included comparison of the efficiency of a vaporizator (HPV, Bioquell) and an aerosolizer using H₂O₂, and peracetic acid (aHPP, Anios) in MDRO environmental disinfection, and assessment of toxicity of these techniques. This prospective cross-over study was conducted in five medical and surgical ICUs located in one University hospital, during a 12-week period. Routine terminal cleaning was followed by H₂O₂ disinfection. A total of 24 environmental bacteriological samplings were collected per room, from eight frequently touched surfaces, at three time-points: after patient discharge (T0), after terminal cleaning (T1) and after H₂O₂ disinfection (T2). In total 182 rooms were studied, including 89 (49%) disinfected with aHPP and 93 (51%) with HPV. At T0, 15/182 (8%) rooms were contaminated with at least 1 MDRO (extended spectrum β-lactamase-producing Gram-negative bacilli 50%, imipenem resistant Acinetobacter baumannii 29%, methicillin-resistant Staphylococcus aureus 17%, and Pseudomonas aeruginosa resistant to ceftazidime or imipenem 4%). Routine terminal cleaning reduced environmental bacterial load (P efficiency on MDRO (15/182 (8%) rooms at T0 versus 11/182 (6%) at T1; P = 0.371). H₂O₂ technologies were efficient for environmental MDRO decontamination (6% of rooms contaminated with MDRO at T1 versus 0.5% at T2, P = 0.004). Patient characteristics were similar in aHPP and HPV groups. No significant difference was found between aHPP and HPV regarding the rate of rooms contaminated with MDRO at T2 (P = 0.313). 42% of room occupants were MDRO carriers. The highest rate of rooms contaminated with MDRO was found in rooms where patients stayed for a longer period of time, and where a patient with MDRO was

  15. DISY. The direct synthesis of hydrogen peroxide, a bridge for innovative applications

    Energy Technology Data Exchange (ETDEWEB)

    Buzzoni, R.; Perego, C. [Eni S.p.A., Novara (Italy). Research Center for Non-Conventional Energies

    2011-07-01

    Hydrogen peroxide is largely recognized as the green oxidant of choice for future sustainable processes. The current industrial production still goes through the old anthraquinone process, a complex, two-step process suffering from a low specific productivity. Following the development of TS-1/H{sub 2}O{sub 2} based selective oxidation processes e.g. propylene epoxidation, cyclohexanone ammoximation and the new benzene direct oxidation to phenol, there has been an incentive for the development of a new technology, simpler and with better economics. DISY process, based on direct synthesis of hydrogen peroxide from hydrogen and oxygen, is highly suitable to the design of integrated selective oxidation processes as well as for production of commercial-grade high concentration aqueous hydrogen peroxide solutions. Catalyst and process development up to pilot scale are described. (orig.)

  16. Salidroside Attenuates Hydrogen Peroxide-Induced Cell Damage Through a cAMP-Dependent Pathway

    Directory of Open Access Journals (Sweden)

    Xuming Deng

    2011-04-01

    Full Text Available Salidroside, a major component of Rhodiola rosea L., has shown various pharmacological functions, including antioxidant effects, but the signal transduction pathway of its antioxidant effects is not very clear. In this study, we found that salidroside could attenuate hydrogen peroxide (H2O2-induced HL-7702 cell damage, inhibit H2O2-induced cytosolic free Ca2+ ([Ca2+]i elevation, scavenge reactive oxygen species (ROS and increase 3’-5’-cyclic adenosine monophosphate (cAMP level in a dose-dependent manner, but it couldn’t influence 3’-5’-cyclic guanosine monophosphate (cGMP levels. Therefore, these results indicated that the antioxidant effects of salidroside were associated with down-regulation of [Ca2+]i, ROS occur via a cAMP-dependent pathway.

  17. [Possible involvement of hydrogen peroxide and salicylic acid in the legume-rhizobium symbiosis].

    Science.gov (United States)

    Glian'ko, A K; Makarova, L E; Vasil'eva, G G; Mironova, N V

    2005-01-01

    H2O2 content was studied in the roots and epicotyls of pea (Pisum sativum L.) with normal (cultivar Marat) and disturbed (non-nodulating mutant K14 and hypernodulating mutant Nod3) regulation of root nodulation after inoculation with active industrial strain of Rhizobium leguminosarum by. viceae 250a/CIAM 1026. Pea biotypes differed by H2O2 content in the roots and epicotyls. Exogenous salicylic acid (SA) (0.2 mM) affected H2O2 and SA contents in the roots in an inoculation-dependent manner. The involvement of hydrogen peroxide and SA as signaling molecules as well as of antibacterial agents in the pea-rhizobium interaction at the initial stages of symbiosis is proposed.

  18. Combined Bleaching Technique Using Low and High Hydrogen Peroxide In-Office Bleaching Gel.

    Science.gov (United States)

    Rezende, M; Ferri, L; Kossatz, S; Loguercio, A D; Reis, A

    2016-01-01

    The aim of this study was to evaluate the efficacy, color stability, risk, and intensity of tooth sensitivity (TS) of combined bleaching techniques performed with 20% or 35% hydrogen peroxide for an in-office protocol. Thirty patients were randomly divided into two groups and submitted to a single 45-minute in-office bleaching session with 35% hydrogen peroxide or 20% hydrogen peroxide. At-home bleaching was performed with 10% carbamide peroxide for two hours daily over the course of two weeks. The color was evaluated with the value-oriented shade guide Vita Classical at different periods up to 12 months after bleaching. Patients recorded the intensity of TS using a five-point verbal scale. Color change data were submitted to a two-way repeated-measures analysis of variance and Tukey test (α=0.05). The absolute risk and intensity of TS were compared with the Fisher exact test and Mann-Whitney test, respectively (α=0.05). On average, an effective and similar whitening of three units in shade guide was observed for both groups, which remained stable for 12 months. When both protocols were compared, the one with hydrogen peroxide 35% showed a higher risk (p=0.02) and intensity of TS (p=0.04). In regard to the TS intensity, no significant difference was observed up to 48 hours after in-office bleaching (p=0.09) and during the at-home bleaching phase of the study (p=0.71). The combined bleaching technique using at-home bleaching associated with in-office bleaching was effective and stable over the course of 12 months, regardless of the concentration of the hydrogen peroxide used for in-office bleaching. However, the protocol with 20% hydrogen peroxide produced lower risk and intensity of TS.

  19. Combined Application of Natural Sunlight and Hydrogen peroxide on the Removal of Harmful Cyanobacteria

    Science.gov (United States)

    Wang, D. H.; Li, L.; Zhu, C. W.; Wang, Z. Y.; Xie, P.

    2017-08-01

    This study provides an efficient and environmentally friendly advanced oxidation technique involving the combined application of natural sunlight and hydrogen peroxide for the removal of harmful cyanobacteria from lakes and reservoirs. In this paper, we collected water samples from Taihu Lake (Wuxi, China) in August 2016 when cyanobacterial blooms had occurred and then performed an outdoor experiment. Hydrogen peroxide at 0.6 mM had no obvious effect on the cyanobacterial inactivation in the dark, even stimulating cyanobacterial growth to some extent. Cyanobacteria were inactivated by higher concentrations of hydrogen peroxide (1.0 mM) in the dark, as well as 0.4 mM hydrogen peroxide under sunlight irradiation, indicating that natural sunlight significantly enhanced the effect of hydrogen peroxide on the removal of cyanobacteria. An experiment involving Pseudanabaena sp. (a harmful species) led to similar conclusions as the study using algae attained from Taihu Lake. This study provides a practical and effective method for controlling harmful cyanobacteria in natural water bodies.

  20. Toxicity of polyhexanide and hydrogen peroxide on human chondrocytes in vitro.

    Science.gov (United States)

    Röhner, Eric; Seeger, Joern B; Hoff, Paula; Dähn-Wollenberg, Stephanie; Perka, Carsten; Matziolis, Georg

    2011-07-07

    The treatment of acute joint infections has an important impact on long-term outcome and remains an unsolved problem. The most frequent bacteria are staphylococci, streptococci, and gram-negative bacteria. In septic surgery, polyhexanide and hydrogen peroxide are the most frequently used local antiseptics. The aim of this study was to examine the hypothesis that antiseptics induce cell death of human chondrocytes after a short incubation time.Human chondrocytes were treated with different concentrations of polyhexanide and hydrogen peroxide. Toxicity analysis was determined by visualization of cell structure using light microscopy, lactate dehydrogenase release, and determination of living and total cell numbers after addition of polyhexanide and hydrogen peroxide. Light microscopic data revealed a defect cell structure after addition of both antiseptics. Lactate dehydrogenase activity showed a significant increase of enzyme expression after a short incubation with polyhexanide. The determination of vital chondrocytes showed a significant decrease of vital and total cell numbers after addition with polyhexanide and hydrogen peroxide.Both antiseptic solutions induce significant cell death of human chondrocytes after a short incubation time. Polyhexanide possibly has more toxic potential than hydrogen peroxide against human chondrocytes after an application >15 minutes. Therefore, both substances should only be applied for a short time (<15 minutes) and the joint irrigated to wash out the antiseptic substance prior to wound closure. Copyright 2011, SLACK Incorporated.

  1. Photochemical production of superoxide and hydrogen peroxide from natural organic matter

    Science.gov (United States)

    Garg, Shikha; Rose, Andrew L.; Waite, T. David

    2011-08-01

    Irradiation of Suwannee River fulvic acid (SRFA) at pH 8.1 with simulated sunlight resulted in production of nanomolar concentrations of superoxide and hydrogen peroxide. SRFA contains a redox-active chromophore which reduced oxygen to yield superoxide upon photoexcitation. Hydrogen peroxide was generated exclusively via uncatalysed disproportionation of superoxide produced in this way. Superoxide decayed through both uncatalysed disproportionation and an oxidative pathway that did not result in hydrogen peroxide production, whereas hydrogen peroxide did not undergo further reaction to any discernible extent over the one-hour duration of irradiation. Singlet oxygen did not contribute substantially to production of superoxide or hydrogen peroxide but was found to play a critical role in controlling the mechanism and associated rate of superoxide decay in the irradiated solution. A kinetic model based on these observations is presented which provides an excellent description of the experimental results and is also consistent with observations from a wide range of other studies in which various aspects of SRFA redox chemistry and photochemistry have been investigated.

  2. Antimicrobial activities of hydrogen peroxide and its activation by a novel heterogeneous Fenton's-like modified PAN catalyst

    National Research Council Canada - National Science Library

    Boateng, M K; Price, S L; Huddersman, K D; Walsh, S E

    2011-01-01

    .... The antimicrobial properties of an iron-based novel heterogeneous polyacrylonitrile catalyst in combination with hydrogen peroxide were examined against Escherichia coli, Pseudomonas aeruginosa...

  3. Solar-Driven Hydrogen Peroxide Production Using Polymer-Supported Carbon Dots as Heterogeneous Catalyst

    Science.gov (United States)

    Gogoi, Satyabrat; Karak, Niranjan

    2017-10-01

    Safe, sustainable, and green production of hydrogen peroxide is an exciting proposition due to the role of hydrogen peroxide as a green oxidant and energy carrier for fuel cells. The current work reports the development of carbon dot-impregnated waterborne hyperbranched polyurethane as a heterogeneous photo-catalyst for solar-driven production of hydrogen peroxide. The results reveal that the carbon dots possess a suitable band-gap of 2.98 eV, which facilitates effective splitting of both water and ethanol under solar irradiation. Inclusion of the carbon dots within the eco-friendly polymeric material ensures their catalytic activity and also provides a facile route for easy catalyst separation, especially from a solubilizing medium. The overall process was performed in accordance with the principles of green chemistry using bio-based precursors and aqueous medium. This work highlights the potential of carbon dots as an effective photo-catalyst.

  4. Chemiluminescence assay for catechin based on generation of hydrogen peroxide in basic solution

    Energy Technology Data Exchange (ETDEWEB)

    Arakawa, Hidetoshi; Kanemitsu, Mahina; Tajima, Noriko; Maeda, Masako

    2002-11-20

    We have determined that the catechin group in basic solution efficiently produces hydrogen peroxide; moreover, a highly sensitive analysis methodology was developed to measure catechin employing a peroxalate chemiluminescence detection system. Identification of hydrogen peroxide generated by catechin was determined by ESR as well as peroxalate chemiluminescence using catalase and SOD. As a result, catechin-generated superoxide by electron reduction to dissolved oxygen in basic solution, followed by production of hydrogen peroxide through dismutation reaction. This method could measure several tea catechins, (+)-catechin (CC), (-)-epigallocatechin-3-gallate (EGCg), (-)-epicatechin-3-gallate (ECG) and gallic acid, with measurement range from 10{sup -7} to 10{sup -3} mol/l and sensitivity of 10{sup -8} mol/l. This method was also applied to the determination of total catechin levels in green tea, black tea and roasted green tea.

  5. Selective and sensitive fluorometric determinations of cobalt(II) and hydrogen peroxide with fluorescein-hydrazide.

    Science.gov (United States)

    Mori, I; Takasaki, K; Fujita, Y; Matsuo, T

    1998-11-01

    Fluorophotometric determinations of cobalt(II) and hydrogen peroxide were investigated by using the fluorescence reaction between fluorescein-hydrazide (fl-NHNH(2)), and/or hydrogen peroxide, cobalt(II), respectively. The calibration graphs were liner in the range of 0-6.0 ng cobalt(II) and 0-1000 ng hydrogen peroxide per 10 ml at an emission wavelength (E(m)) of 530 nm with an exicitation wavelength (E(x)) of 508 nm, respectively. These proposed methods were selective and simple, and the effect of foreign ions was negligible in comparison with conventional reported methods such as nitroso R,4-(2-pyridylazo)resorcinol(PAR), alizarin, pyridine-2-aldehyde-2-pyridinehydrazone, stilbazo-cobalt(II), etc.

  6. Surface Passivation of CdZnTe Detector by Hydrogen Peroxide Solution Etching

    Science.gov (United States)

    Hayes, M.; Chen, H.; Chattopadhyay, K.; Burger, A.; James, R. B.

    1998-01-01

    The spectral resolution of room temperature nuclear radiation detectors such as CdZnTe is usually limited by the presence of conducting surface species that increase the surface leakage current. Studies have shown that the leakage current can be reduced by proper surface preparation. In this study, we try to optimize the performance of CdZnTe detector by etching the detector with hydrogen peroxide solution as function of concentration and etching time. The passivation effect that hydrogen peroxide introduces have been investigated by current-voltage (I-V) measurement on both parallel strips and metal-semiconductor-metal configurations. The improvements on the spectral response of Fe-55 and 241Am due to hydrogen peroxide treatment are presented and discussed.

  7. Ultrafast Shock Interrogation of Hydrogen Peroxide/Water Mixtures: Thermochemical Predictions of Shock Condition Chemistry

    Science.gov (United States)

    Zaug, Joseph; Armstrong, Michael; Bastea, Sorin; Carter, Jeffrey; Kuo, I.-F. William; Crowhurst, Jonathan; Grant, Christian

    2012-02-01

    Hydrogen peroxide is a powerful oxidizer and its concentrated aqueous solutions exhibit very high reactivity, even sustaining detonation under strong enough confinement. Due to its simple composition and basic expected decomposition kinetics hydrogen peroxide is very suitable for studying the interplay of high pressures, temperatures and reactivity and their effect on the equation of state, particularly at the boundary between detonating and non-detonating behavior. To this end we performed speed of sound and picosecond time resolved shock measurements on solutions of hydrogen peroxide of concentrations from 30 to 90 percent, and analyzed the results in terms of common assumptions of chemical equilibrium in reactive fluid mixtures. Experimental shock states were achieved up to a maximum pressure of 20 GPa with corresponding shock velocities of 6-7 km/sec.

  8. Hydrogen peroxide attenuates store-operated calcium entry and enhances calcium extrusion in thyroid FRTL-5 cells.

    OpenAIRE

    Törnquist, K; Vainio, P J; Björklund, S; Titievsky, A; Dugué, B; Tuominen, R K

    2000-01-01

    Redox modulation participates in the regulation of intracellular free calcium concentration ([Ca(2+)](i)) in several cell types. In thyroid cells, including FRTL-5 cells, changes in [Ca(2+)](i) regulate several important functions, including the production of H(2)O(2) (hydrogen peroxide). As H(2)O(2) is of crucial importance for the production of thyroid hormones, we investigated the effects of H(2)O(2) on [Ca(2+)](i) in thyroid FRTL-5 cells. H(2)O(2) itself did not modulate basal [Ca(2+)](i)...

  9. Effects of fulvic acid on Fe(II) oxidation by hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Voelker, B.M.; Sulzberger, B. [Swiss Federal Inst. for Environmental Science and Technology (EAWAG), Duebendorf (Switzerland)

    1996-04-01

    Iron redox cycling can catalyze the oxidation of humic substances and increase the rate of oxygen consumption in surface waters rich in iron and organic carbon. This study examines the role of Fenton`s reaction [oxidation of Fe(II) by hydrogen peroxide] in this catalytic cycle. A number of competing processes were observed in model systems containing dissolved Fe, hydrogen peroxide, and Suwannee River fulvic acid. First, the effective rate constant of Fenton`s reaction increased with increasing fulvic acid concentration, indicating the formation Fe(II)-fulvate complexes that react more rapidly with hydrogen peroxide than Fe(II)-aquo complexes. This effect was significant at pH 5 but negligible at pH 3. A second effect was scavenging of the HO{sup .} radical produced in Fenton`s reaction by fulvic acid, forming an organic radical. The organic radical reduced oxygen to HO{sub 2}{sup .}/O{sub 2}{sup .-}, which then regenerated hydrogen peroxide by reaction with Fe(II). Finally, Fe(III) was reduced by a dark reaction with fulvic acid, characterized by an initially fast reduction followed by slower processes. The behavior of Fe(II) and hydrogen peroxide over time in the presence of fulvic acid and oxygen could be described by a kinetic model taking all of these reactions into account. The net result was an iron redox cycle in which hydrogen peroxide as well as oxygen were consumed (even though direct oxidation of Fe(II) by oxygen was not significant), and the oxidation of fulvic acid was accelerated. 56 refs., 7 figs., 1 tab.

  10. Mechanical wounding-induced laticifer differentiation in rubber tree: An indicative role of dehydration, hydrogen peroxide, and jasmonates.

    Science.gov (United States)

    Tian, Wei-Min; Yang, Shu-Guang; Shi, Min-Jing; Zhang, Shi-Xin; Wu, Ji-Lin

    2015-06-15

    The secondary laticifer in the secondary phloem of rubber tree are a specific tissue differentiating from vascular cambia. The number of the secondary laticifers is closely related to the rubber productivity of Hevea. Factors involved in the mechanical wounding-induced laticifer differentiation were analyzed by using paraffin section, gas chromatography-mass spectrometry (GC-MS), and Northern-blot techniques. Dehydration of the wounded bark tissues triggered a burst of hydrogen peroxide, abscisic acid, and jasmonates and up-regulated the expression of HbAOSa, which was associated with the secondary laticifer differentiation strictly limited to the wounded area. Application of exogenous hydrogen peroxide, methyl jasmonate, and polyethylene glycol 6000 (PEG6000) could induce the secondary laticifer differentiation, respectively. Moreover, 6-Benzylaminopurine, a synthetic cytokinin, enhanced the methyl jasmonate-induced secondary laticifer differentiation. However, the dehydration-induced secondary laticifer differentiation was inhibited by exogenous abscisic acid. Diphenyleneiodonium chloride (DPI), a specific inhibitor of NADPH oxidase, was effective in inhibiting the accumulation of hydrogen peroxide as well as of jasmonates upon dehydration. It blocked the dehydration-induced but not the methyl jasmonate-induced secondary laticifer differentiation. The results suggested a stress signal pathway mediating the wound-induced secondary laticifer differentiation in rubber tree. Copyright © 2015 Elsevier GmbH. All rights reserved.

  11. Transcriptional analysis of Mycobacterium fortuitum cultures upon hydrogen peroxide treatment using the novel standard rrnA-P1

    Directory of Open Access Journals (Sweden)

    Rebollo María

    2008-06-01

    Full Text Available Abstract Background The ability of an intracellular pathogen to establish infection depends on the capacity of the organism to survive and replicate inside the host. Mycobacterium fortuitum is a bacteria that contains genes involved in the detoxification of the oxygen reactive species such as those produced by the host during the infection. In this work, we investigate the effects of hydrogen peroxide on the transcription and expression of these genes by developing a real time quantitative PCR technique (qRT-PCR using the ribosomal promoter region (rrnA-P1 as reference product for quantification of the mRNA levels. Results M. fortuitum cultures were treated with different hydrogen peroxide concentrations (0.02 to 20 mM during several periods of time (30 to 120 minutes. The activity of the enzymes KatGII and SodA, and the transcription of corresponding genes were evaluated. The transcriptional regulator furAII gene was also studied. The ribosomal promoter region rrnA-P1 was validated as referential product under the stress conditions checked by qRT-PCR. Minor changes were observed under the conditions tested except when bacteria were incubated in the presence of 20 mM hydrogen peroxide. Under those conditions, the levels of transcription of the three genes under study increased at 30 minutes of treatment. The viability of the bacteria was not influenced under the conditions tested. Conclusion In this work, we have quantified transcriptional responses to stress suggesting that, the opportunistic pathogen M. fortuitum is more resistant and differs in behaviour in the presence of hydrogen peroxide, when compared to the major pathogen Mycobacterium tuberculosis and the saprophyte Mycobacterium smegmatis. Besides, we demonstrate the mycobacterial non-coding region rrnA-P1 to be a suitable reference product in the analysis of qRT-PCR transcriptional data of M. fortuitum.

  12. Electrochemical synthesis of macroporous zinc oxide layers by employing hydrogen peroxide as oxygen precursor

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, Daniel [Laboratoire d' Electrochimie et Chimie Analytique (UMR CNRS 7575), Ecole Nationale Superieure de Chimie de Paris (ENSCP) (France); Instituto de Quimica, Pontificia Universidad Catolica de Valparaiso, Valparaiso (Chile); Bartlett, Philip; Abdelsalam, Mamdouh [School of Chemistry, University of Southampton (United Kingdom); Gomez, Humberto [Instituto de Quimica, Pontificia Universidad Catolica de Valparaiso, Valparaiso (Chile); Lincot, Daniel [Laboratoire d' Electrochimie et Chimie Analytique (UMR CNRS 7575), Ecole Nationale Superieure de Chimie de Paris (ENSCP) (France)

    2008-10-15

    Two- and three-dimensional ordered porous zinc oxide (ZnO) films were prepared by electrodeposition on Indium Tin Oxide coated glass, using two- and three-dimensional poly(styrene) opal templates. The oxide was formed by electrochemical reduction of hydrogen peroxide in aqueous zinc perchlorate solution. Scanning electron microscopy measurements showed well ordered inverse opal structures for macroporous ZnO. At high hydrogen peroxide concentration, dense inner conformal filling was achieved for 2D and 3D structures. The formation of nanocrystalline ZnO was checked by X-ray diffraction. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. Effect of endogenous and synthetic antioxidants on hydrogen peroxide-induced guinea-pig colon contraction.

    Science.gov (United States)

    Wan, B Y C; Mann, S; Assem, E S K; Marson, C M

    2010-03-01

    The effects of the endogenous antioxidant alpha-lipoic acid on guinea pig colon smooth muscle contraction (Gpcc) induced by hydrogen peroxide were examined. Having previously shown that the histone deacetylase (HDAC) benzamide inhibitor MGCD0103 inhibits guinea-pig smooth muscle contraction, as do various sulfur-containing antioxidants, we asked whether hybrid compounds possessing both alpha-lipoic acid-derived antioxidant properties and HDAC inhibitory activity could inhibit Gpcc. Guinea pig colon (Gpc) was incubated at 37 degrees C with Krebs buffer; the four stimulants-hydrogen peroxide, carbachol, histamine, and sodium fluoride-were added independently. The response to each stimulant alone was compared with that in the presence of each of the test compounds: MGCD0103, alpha-lipoic acid, and two of their hybrids, UCL M084 and UCL M109. NaF (10 mM), carbachol (0.05 microM), histamine (0.1 microM), and hydrogen peroxide (1 microM) produced Gpcc of about 50-60% above basal level. With the exception of MGCD0103 against hydrogen peroxide, all four test compounds at 1 microM-MGCD0103, alpha-lipoic acid, UCL M084, and UCL M109-produced a significant inhibition of 35-60% of Gpcc induced by hydrogen peroxide, NaF, and carbachol, although none reduced histamine or ovalbumin-induced Gpcc. Benzalkonium chloride (Bcl), a G-protein inhibitor, reduced the hydrogen peroxide-induced Gpcc by 35%. Contraction by stimulants used to induce Gpcc is known to involve G-proteins. All four test compounds-MGCD0103, alpha-lipoic acid and two of their hybrids, UCL M084 and UCL M109-reduced Gpcc induced by NaF and carbachol, suggesting that G-protein pathway involvement is relevant to the action of the test compounds, as is also indicated by the Bcl-induced inhibition of hydrogen peroxide-induced contractions. Additionally, alpha-lipoic acid and the two hybrids showed >30% inhibition of hydrogen peroxide-induced contractions, consistent with the antioxidant properties of the 1,2-dithiolane

  14. Power generation in fuel cells using liquid methanol and hydrogen peroxide

    Science.gov (United States)

    Narayanan, Sekharipuram R. (Inventor); Valdez, Thomas I. (Inventor); Chun, William (Inventor)

    2002-01-01

    The invention is directed to an encapsulated fuel cell including a methanol source that feeds liquid methanol (CH.sub.3 OH) to an anode. The anode is electrical communication with a load that provides electrical power. The fuel cell also includes a hydrogen peroxide source that feeds liquid hydrogen peroxide (H.sub.2 O.sub.2) to the cathode. The cathode is also in communication with the electrical load. The anode and cathode are in contact with and separated by a proton-conducting polymer electrolyte membrane.

  15. Domination of thermodynamically demanding oxidative processes in reaction of iodine with hydrogen peroxide

    Science.gov (United States)

    Stevanović, Kristina Z.; Bubanja, Itana Nuša M.; Stanisavljev, Dragomir R.

    2017-09-01

    We investigated the degree of isothermal iodine conversion to iodate as one of the most intriguing steps of the Bray-Liebhafsky oscillator. The amount of the produced iodate, in the presence of hydrogen peroxide, was determined by the stopped-flow titration with iodide ions. From five different experiments, high degree of iodine conversion to iodate (95.4 ± 0.6)% is obtained. It confirmed that, after the induction period of spontaneous hydrogen peroxide catalytic decomposition, reaction dynamics is dominated by thermodynamically demanding oxidative processes. Isothermal change of the reaction dynamics introduces some specific energy redistribution as a possible initiator of oxidizing radicals.

  16. Nerve growth factor promotes killing of Leishmania donovani by macrophages through the induction of hydrogen peroxide.

    Science.gov (United States)

    Chiba, Rieko; Amagai, Yosuke; Tanaka, Akane; Katakura, Ken; Matsuda, Hiroshi

    2014-08-01

    Visceral leishmaniasis is protozoonosis that occurs worldwide and still requires effective therapies with less toxicity. In this study, we examined the antileishmanial effect of nerve growth factor (NGF) using a murine infection model. NGF blocked the infection of macrophages by Leishmania donovani, which was completely cancelled by a hydrogen peroxide inhibitor. In vivo, not only did NGF show antileishmanial effects, but combination therapy of NGF and sodium stibogluconate synergistically exhibited the activity more potently than each monotherapy. These results indicate that NGF exerts antileishmanial effect by stimulating hydrogen peroxide production in macrophages and can be a novel therapy for leishmaniasis. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  17. Artificial photosynthesis for production of hydrogen peroxide and its fuel cells.

    Science.gov (United States)

    Fukuzumi, Shunichi

    2016-05-01

    The reducing power released from photosystem I (PSI) via ferredoxin enables the reduction of NADP(+) to NADPH, which is essential in the Calvin-Benson cycle to make sugars in photosynthesis. Alternatively, PSI can reduce O2 to produce hydrogen peroxide as a fuel. This article describes the artificial version of the photocatalytic production of hydrogen peroxide from water and O2 using solar energy. Hydrogen peroxide is used as a fuel in hydrogen peroxide fuel cells to make electricity. The combination of the photocatalytic H2O2 production from water and O2 using solar energy with one-compartment H2O2 fuel cells provides on-site production and usage of H2O2 as a more useful and promising solar fuel than hydrogen. This article is part of a Special Issue entitled Biodesign for Bioenergetics--The design and engineering of electronc transfer cofactors, proteins and protein networks, edited by Ronald L. Koder and J.L. Ross Anderson. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Silver-palladium catalysts for the direct synthesis of hydrogen peroxide

    Science.gov (United States)

    Khan, Zainab; Dummer, Nicholas F.; Edwards, Jennifer K.

    2017-11-01

    A series of bimetallic silver-palladium catalysts supported on titania were prepared by wet impregnation and assessed for the direct synthesis of hydrogen peroxide, and its subsequent side reactions. The addition of silver to a palladium catalyst was found to significantly decrease hydrogen peroxide productivity and hydrogenation, but crucially increase the rate of decomposition. The decomposition product, which is predominantly hydroxyl radicals, can be used to decrease bacterial colonies. The interaction between silver and palladium was characterized using scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and temperature programmed reduction (TPR). The results of the TPR and XPS indicated the formation of a silver-palladium alloy. The optimal 1% Ag-4% Pd/TiO2 bimetallic catalyst was able to produce approximately 200 ppm of H2O2 in 30 min. The findings demonstrate that AgPd/TiO2 catalysts are active for the synthesis of hydrogen peroxide and its subsequent decomposition to reactive oxygen species. The catalysts are promising for use in wastewater treatment as they combine the disinfectant properties of silver, hydrogen peroxide production and subsequent decomposition. This article is part of a discussion meeting issue 'Providing sustainable catalytic solutions for a rapidly changing world'.

  19. Hydrogen Peroxide-induced Cell Death in Arabidopsis : Transcriptional and Mutant Analysis Reveals a Role of an Oxoglutarate-dependent Dioxygenase Gene in the Cell Death Process

    NARCIS (Netherlands)

    Gechev, Tsanko S.; Minkov, Ivan N.; Hille, Jacques

    2005-01-01

    Hydrogen peroxide is a major regulator of plant programmed cell death (PCD) but little is known about the downstream genes from the H2O2-signaling network that mediate the cell death. To address this question, a novel system for studying H2O2-induced programmed cell death in Arabidopsis thaliana was

  20. Hydrogen peroxide as sustainable fuel: electrocatalysts for production with a solar cell and decomposition with a fuel cell.

    Science.gov (United States)

    Yamada, Yusuke; Fukunishi, Yurie; Yamazaki, Shin-ichi; Fukuzumi, Shunichi

    2010-10-21

    Hydrogen peroxide was electrochemically produced by reducing oxygen in an aqueous solution with [Co(TCPP)] as a catalyst and photovoltaic solar cell operating at 0.5 V. Hydrogen peroxide thus produced is utilized as a fuel for a one-compartment fuel cell with Ag-Pb alloy nanoparticles as the cathode.

  1. Introduction of Hydrogen Peroxide as an Oxidant in Flow Injection Analysis: Speciation of Cr(III) and Cr(VI)

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov

    1998-01-01

    Hydrogen peroxide was used as an oxidant in Flow Injection Analysis (FIA). The formation of gaseous components during the analysis was suppressed by maintaining a concentration lower than 0.15% of hydrogen peroxide in 0.1 M NaOH. By this method Cr(III) was oxidised on-line to Cr(VI) which...

  2. Determination of hydrogen peroxide concentration using a handheld Raman spectrometer: Detection of an explosives precursor.

    Science.gov (United States)

    Stewart, S P; Bell, S E J; McAuley, D; Baird, I; Speers, S J; Kee, G

    2012-03-10

    It has been shown that a handheld Raman spectrometer can be used to determine hydrogen peroxide concentration in aqueous solutions in seconds. To allow quantitative analysis, the aqueous peroxide samples were mixed 50/50 (v/v) with a 4mol/dm(3) sodium perchlorate solution which acted as the internal standard. Standard calibration using relative peak heights of the strongest perchlorate (932cm(-1)) and peroxide bands (876cm(-1)) gave an average error of 1.43% for samples in the range 5-30% peroxide. PLS regression of the same data set gave an average error of 0.98%. In addition, the concentrations of the samples were estimated by searching spectra against a library of standard spectra prepared using the same range of peroxide concentrations at 5% increments and with the same perchlorate internal standard. It was found that the library searching method classified all the test samples correctly, matching either the spectra of the same concentration, if they were present, or matching to the closest concentration if an exact match was not possible. This method thus provides a very rapid technique to allow determination of hydrogen peroxide concentrations in the field, for example at suspected improvised explosives manufacturing sites, without complex calibration procedures. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  3. Influence of Growth Medium on Hydrogen Peroxide and Bacteriocin Production of Lactobacillus Strains

    Directory of Open Access Journals (Sweden)

    Edina Németh

    2005-01-01

    Full Text Available This study was conducted to investigate the inhibitory effect of bacteriocin and the production of hydrogen peroxide by four non-starter lactic acid bacteria, Lactobacillus plantarum 2142, Lactobacillus curvatus 2770, Lactobacillus curvatus 2775, Lactobacillus casei subsp. pseudoplantarum 2750 and the probiotic strain Lactobacillus casei Shirota, propagated in de Man Rogosa Sharpe (MRS and tomato juice (TJ broth. The methods were a commonly used agar diffusion technique and a microtiter assay method. The best peroxide-producing Lactobacillus strain was selected for screening the inhibitory activity against Listeria monocytogenes, Bacillus cereus, Escherichia coli and the activity of bacteriocins against Lactobacillus sakei and Candida glabrata. All of the investigated lactic acid bacteria (LAB strains grown in MRS broth produced the highest concentration of hydrogen peroxide ranging from 2–6 g/mL after 72 h of storage. L. plantarum 2142 produced enough hydrogen peroxide already after 24 h at 5 °C in phosphate buffer to inhibit the growth of L. monocytogenes and B. cereus. Crude bacteriocin suspension from the investigated LAB inhibited only slightly the growth of L. sakei, however, the same suspension from MRS completely inhibited the 6-fold diluted yeast suspension. The concentrated bacteriocin suspensions from the both broths inhibited the growth of L. sakei completely. Among the strains, L. plantarum 2142 seemed to be the best peroxide and bacteriocin producer, and the antimicrobial metabolite production was better in MRS than in TJ broth.

  4. Influence of hydrogen peroxide bleaching gels on color, opacity, and fluorescence of composite resins.

    Science.gov (United States)

    Torres, C R G; Ribeiro, C F; Bresciani, E; Borges, A B

    2012-01-01

    The aim of the present study was to evaluate the effect of 20% and 35% hydrogen peroxide bleaching gels on the color, opacity, and fluorescence of composite resins. Seven composite resin brands were tested and 30 specimens, 3-mm in diameter and 2-mm thick, of each material were fabricated, for a total of 210 specimens. The specimens of each tested material were divided into three subgroups (n=10) according to the bleaching therapy tested: 20% hydrogen peroxide gel, 35% hydroxide peroxide gel, and the control group. The baseline color, opacity, and fluorescence were assessed by spectrophotometry. Four 30-minute bleaching gel applications, two hours in total, were performed. The control group did not receive bleaching treatment and was stored in deionized water. Final assessments were performed, and data were analyzed by two-way analysis of variance and Tukey tests (ptherapies (phydrogen peroxide gel. No difference in opacity was detected for all analyzed parameters. Fluorescence changes were influenced by composite resin brand (ptherapy (p=0.0016) used. No significant differences in fluorescence between different bleaching gel concentrations were detected by Tukey test. The greatest fluorescence alteration was detected on the brand Z350. It was concluded that 35% hydrogen peroxide bleaching gel generated the greatest color change among all evaluated materials. No statistical opacity changes were detected for all tested variables, and significant fluorescence changes were dependent on the material and bleaching therapy, regardless of the gel concentration.

  5. Electroactive gate materials for a hydrogen peroxide sensitive E-MOSFET

    NARCIS (Netherlands)

    Dam, T.V.A.; Olthuis, Wouter; Bergveld, Piet

    2002-01-01

    Describes the detection principle of a hydrogen peroxide sensor based on the electrolyte metal oxide semiconductor field effect transistor (EMOSFET) and possibilities of using different types of redox materials as the gate material for the sensor with respect to the sensitivity and detection limit.

  6. 78 FR 73697 - New Animal Drugs; Hyaluronate Sodium; Hydrogen Peroxide; Imidacloprid and Moxidectin; Change of...

    Science.gov (United States)

    2013-12-09

    ...; Hyaluronate Sodium; Hydrogen Peroxide; Imidacloprid and Moxidectin; Change of Sponsor AGENCY: Food and Drug... Dogs (imidacloprid approval for the Division, P.O. Box and moxidectin) treatment of 390, Shawnee... (imidacloprid approval for the Division, P.O. Box and moxidectin) prevention of 390, Shawnee Topical Solution...

  7. Effect of foliar application of salicylic acid, hydrogen peroxide and a ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Biosciences; Volume 42; Issue 2. Effect of foliar application of salicylic acid, hydrogen peroxide and a xyloglucan oligosaccharide on capsiate content and gene expression associatedwith capsinoids synthesis in Capsicum annuum L. AY ZUNUN-PÉREZ T GUEVARA-FIGUEROA SN ...

  8. First Principles Modeling of the Performance of a Hydrogen-Peroxide-Driven Chem-E-Car

    Science.gov (United States)

    Farhadi, Maryam; Azadi, Pooya; Zarinpanjeh, Nima

    2009-01-01

    In this study, performance of a hydrogen-peroxide-driven car has been simulated using basic conservation laws and a few numbers of auxiliary equations. A numerical method was implemented to solve sets of highly non-linear ordinary differential equations. Transient pressure and the corresponding traveled distance for three different car weights are…

  9. Natural manganese deposits as catalyst for decomposing hydrogen peroxide (discussion paper)

    NARCIS (Netherlands)

    Knol, A.H.; Lekkerkerker-Teunissen, K.; Van Dijk, J.C.

    2015-01-01

    Drinking water companies more and more implement Advanced Oxidation Processes (AOP) in their treatment schemes to increase the barrier against organic micropollutants (OMPs). It is necessary to decompose the excessive hydrogen peroxide after applying AOP to avoid negative effects in the following,

  10. Solvent-dependent regioselective oxidation of trans-chalcones using aqueous hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Wang; Jiabin, Yang; Lushen, Li, E-mail: jimin@seu.edu.cn [Southeast University, Nanjing (China). School of Biological Science and Medical Engineering; Jin, Cai; Chunlong, Sun; Min, Ji [Southeast University, Nanjing (China). School of Chemistry and Chemical Engineering

    2013-03-15

    A novel method for regioselective oxidation of trans-chalcones with hydrogen peroxide in acetonitrile to afford cinnamic acids is reported. Only trans-b-arylacrylic acids were observed. A wide range of functionalized products can be effectively produced from various chalcones in good to excellent yields. (author)

  11. Hydrogen peroxide and superoxide radical formation in anaerobic broth media exposed to atmospheric oxygen.

    Science.gov (United States)

    Carlsson, J; Nyberg, G; Wrethén, J

    1978-08-01

    Fourteen different broth media were autoclaved under anaerobic conditions and then exposed to atmospheric oxygen. The hydrogen peroxide and superoxide radical formation as well as the bactericidal effect of the media were studied. The rate of killing of Peptostreptococcus anaerobius VPI 4330-1 was high in media that rapidly autoxidized and accumulated hydrogen peroxide. In actinomyces broth (BBL), 50% of the cells were killed within 2 min, and in Brewer thioglycolate medium (Difco), 50% were killed within 11 min, whereas more than 50% of the cells survived for more than 2 h in Clausen medium (Oxoid), fluid thioglycolate medium (BBL), and thioglycolate medium without dextrose or indicator (Difco). Only media that contained phosphate and glucose had a tendency to accumulate hydrogen peroxide. A solution of phosphate and glucose autoxidized when it had been heated to 120 degrees C for at least 5 min and when the pH of the solution was higher than 6.5. Transitional metal ions catalyzed the autoxidation, but they were not necessary for the reaction to occur. Of the other substances heated in phosphate buffer, only alpha-hydroxycarbonyl compounds autoxidized with accumulation of hydrogen peroxide. Superoxide dismutase decreased the autoxidation rate of most of the broth media. This indicated that superoxide radicals were generated in these media.

  12. Developing an amperometric hydrogen peroxide sensor for an exhaled breath analysis system

    NARCIS (Netherlands)

    Wiedemair, Justyna; van Dorp, Henriëtte; Olthuis, Wouter; van den Berg, Albert

    In this work, we present a chip-integrated amperometric sensor targeted at the detection of hydrogen peroxide (H2O2) in the gaseous phase. Electrode chips are manufactured in a series of microfabrication steps and characterized electrochemically. Using such devices detection of H2O2 in an aqueous

  13. An efficient and reproducible method for measuring hydrogen peroxide in exhaled breath condensate.

    NARCIS (Netherlands)

    Beurden, W.J.C van; Harff, G.A.; Dekhuijzen, P.N.R.; Bosch, M.J. van den; Creemers, J.P.H.M.; Smeenk, F.J.M.W.

    2002-01-01

    We investigated the sensitivity and reproducibility of a test procedure for measuring hydrogen peroxide (H202) in exhaled breath condensate and the effect of storage of the condensate on the H2O2 concentration, and compared the results to previous studies.Twenty stable COPD patients breathed into

  14. Role of hydrogen peroxide during the interaction between the hemibiotrophic fungal pathogen Septoria tritici and wheat

    NARCIS (Netherlands)

    Shetty, N.P.; Mehrabi, R.; Lütken, H.; Haldrup, A.; Kema, G.H.J.

    2007-01-01

    Hydrogen peroxide (H2O2) is reported to inhibit biotrophic but benefit necrotrophic pathogens. Infection by necrotrophs can result in a massive accumulation of H2O2 in hosts. Little is known of how pathogens with both growth types are affected (hemibiotrophs). The hemibiotroph, Septoria tritici,

  15. Low-level hydrogen peroxide generation by unbleached cotton nonwovens: implications for wound healing applications

    Science.gov (United States)

    Greige cotton is an intact plant fiber. The cuticle and primary cell wall near the outer surface of the cotton fiber contains pectin, peroxidases, superoxide dismutase (SOD), and trace metals, which are associated with hydrogen peroxide (H2O2) generation during cotton fiber development. The compon...

  16. Reaction path sampling of the reaction between iron(II) and hydrogen peroxide in aqueous solution

    NARCIS (Netherlands)

    Ensing, B.; Baerends, E.J.

    2002-01-01

    Previously, we have studied the coordination and dissociation of hydrogen peroxide with iron(II) in aqueous solution by Car-Parrinello molecular dynamics at room temperature. We presented a few illustrative reaction events, in which the ferryl ion ([Fe(IV)O

  17. A comparison of the bleaching effectiveness of chlorine dioxide and hydrogen peroxide on dental composite.

    Science.gov (United States)

    Agnihotry, Anirudha; Gill, Karanjot S; Singhal, Deepak; Fedorowicz, Zbys; Dash, Sambit; Pedrazzi, Vinicius

    2014-01-01

    This study was carried out to verify if composites could be bleached using chlorine dioxide as compared with hydrogen peroxide. 3M ESPE Filtek Z350 Universal Restorative discs were prepared (n=40), with dimensions 5 mm diameter x 2 mm thickness. The discs were divided into 4 groups of 10 discs each. Color assessment was performed by CIEDE2000. The discs were stained with coffee, tea, wine and distilled water (control) solutions for 14 days, 5 hours daily. Color assessment was repeated on stained discs and followed by bleaching of 5 discs from each group using chlorine dioxide and hydrogen peroxide in-office systems. Finally, a last color assessment was performed and compared statistically. DE2000 after bleaching was very close to baseline for both the bleaching agents, although chlorine dioxide showed better results than hydrogen peroxide. After staining, there was a clinically significant discoloration (∆E2000≥3.43) for the tea, coffee and wine groups, and discoloration (∆E2000) was seen more in the wine group as compared to tea and coffee. Overall, the control group (distilled water) had the least color change in the three intervals. After bleaching, the color in all specimens returned close to the baseline. The color differences between bleaching and baseline were less than 3.43 for all groups. The obtained results show that chlorine dioxide is slightly superior to hydrogen peroxide in the bleaching of composites, while maintaining the shade of the composite close to the baseline.

  18. Stabilization of hydrogen peroxide using tartaric acids in Fenton and fenton-like oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Hyung Suk; Kim, Jeong-Jin; Kim, Young-Hun [Andong National University, Andong (Korea, Republic of)

    2016-03-15

    The stabilization of hydrogen peroxide is a key factor in the efficiency of a Fenton reaction. The stability of hydrogen peroxide was evaluated in a Fenton reaction and Fenton-like reactions in the presence of tartaric acid as a stabilizer. The interactions between ferrous or ferric iron and tartaric acid were observed through spectroscopic monitoring at variable pH around pKa{sub 1} and pKa{sub 2} of the stabilizer. Ferric iron had a strong interaction with the stabilizer, and the strong interaction was dominant above pKa{sub 2}. At a low pH, below pKa{sub 1}, the stabilizing effect was at its maximum and the prolonged life-time of hydrogen peroxide gave a higher efficiency to the oxidative degradation of nitrobenzene. In Fenton-like reactions with hematite, the acidic conditions caused dissolution of iron from an iron oxide, and an increase in iron species was the result. Tartaric acid showed a stabilizing effect on hydrogen peroxide in the Fentonlike system. The stabilization by tartaric acid might be due to an inhibition of catalytic activity of dissolved iron, and the stabilization strongly depends on the ionization state of the stabilizer.

  19. Optimization study on the hydrogen peroxide pretreatment and production of bioethanol from seaweed Ulva prolifera biomass.

    Science.gov (United States)

    Li, Yinping; Cui, Jiefen; Zhang, Gaoli; Liu, Zhengkun; Guan, Huashi; Hwang, Hueymin; Aker, Winfred G; Wang, Peng

    2016-08-01

    The seaweed Ulva prolifera, distributed in inter-tidal zones worldwide, contains a large percentage of cellulosic materials. The technical feasibility of using U. prolifera residue (UPR) obtained after extraction of polysaccharides as a renewable energy resource was investigated. An environment-friendly and economical pretreatment process was conducted using hydrogen peroxide. The hydrogen peroxide pretreatment improved the efficiency of enzymatic hydrolysis. The resulting yield of reducing sugar reached a maximum of 0.42g/g UPR under the optimal pretreatment condition (hydrogen peroxide 0.2%, 50°C, pH 4.0, 12h). The rate of conversion of reducing sugar in the concentrated hydrolysates to bioethanol reached 31.4% by Saccharomyces cerevisiae fermentation, which corresponds to 61.7% of the theoretical maximum yield. Compared with other reported traditional processes on Ulva biomass, the reducing sugar and bioethanol yield are substantially higher. Thus, hydrogen peroxide pretreatment is an effective enhancement of the process of bioethanol production from the seaweed U. prolifera. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Amperometric mediatorless hydrogen peroxide sensor with horseradish peroxidase encapsulated in peptide nanotubes

    Directory of Open Access Journals (Sweden)

    Hamid Feyzizarnagh

    2016-03-01

    Full Text Available A mediatorless sensor with horseradish peroxidase (HRP enzymes encapsulated inside peptide nanotubes (PNTs has been proposed for amperometric detection of hydrogen peroxide. PNTs not only encapsulate the enzymes to retain their activity and stability, but also can provide direct electron transfer between an electrode and the electroactive sites of HRP without mediators. Experimental results were compared with hydroquinone (HQ-mediated electron transfer results. The PNT/HRP sensor produced a current signal comparable to the HQ/HRP sensor in the entire range of hydrogen peroxide concentrations (0–60 mM. The amperometric signal was the greatest when PNT and HQ were used together. The current signal of the PNT/HQ/HRP system increased rapidly with the hydrogen peroxide concentration while the PNT/HRP and HQ/HRP systems showed a similar increase in the rate of current with hydrogen peroxide. The current-H2O2 concentration relations of the tested systems were analyzed using the Michaelis–Menten type equation. Using PNTs as immobilizing agents for enzymes may circumvent the drawbacks of chemical mediators such as HQ that may interfere with the redox reactions and may cause toxicity problems to enzymes.

  1. Formation of water-soluble soybean polysaccharides from spent flakes by hydrogen peroxide treatment

    DEFF Research Database (Denmark)

    Pierce, Brian; Wichmann, Jesper; Tran, Tam H.

    2016-01-01

    In this paper we propose a novel chemical process for the generation of water-soluble polysaccharides from soy spent flake, a by-product of the soy food industry. This process entails treatment of spent flake with hydrogen peroxide at an elevated temperature, resulting in the release of more than...

  2. Environmental meticillin-resistant Staphylococcus aureus (MRSA) disinfection using dry-mist-generated hydrogen peroxide

    DEFF Research Database (Denmark)

    Bartels, M.D.; Kristoffersen, K.; Slotsbjerg, T.

    2008-01-01

    Meticillin-resistant Staphylococcus aureus (MRSA) is a major problem in hospitals worldwide. Hand hygiene is recognised as crucial in limiting the spread of MRSA but less is known about the role of MRSA reservoirs in the inanimate hospital environment. We evaluated the effect of hydrogen peroxide...

  3. Efficient hydrogen peroxide decomposition to oxygen and water catalysed by a ruthenium pincer complex

    DEFF Research Database (Denmark)

    Nielsen, Martin

    2016-01-01

    are necessary, further enhancing the potential scope of this system. By the use of the homogeneous catalyst Ru(H)2(PNPiPr)CO, it is possible to obtain turnover frequencies reaching 180,000 h−1 and turnover numbers more than 14,000 in a neutral hydrogen peroxide aqueous solution at 25 °C. Overall, findings...

  4. Several pathways of hydrogen peroxide action that damage the E. coli genome

    Directory of Open Access Journals (Sweden)

    Nasser Ribeiro Asad

    2004-01-01

    Full Text Available Hydrogen peroxide is an important reactive oxygen species (ROS that arises either during the aerobic respiration process or as a by-product of water radiolysis after exposure to ionizing radiation. The reaction of hydrogen peroxide with transition metals imposes on cells an oxidative stress condition that can result in damage to cell components such as proteins, lipids and principally to DNA, leading to mutagenesis and cell death. Escherichia coli cells are able to deal with these adverse events via DNA repair mechanisms, which enable them to recover their genome integrity. These include base excision repair (BER, nucleotide excision repair (NER and recombinational repair. Other important defense mechanisms present in Escherichia coli are OxyR and SosRS anti-oxidant inducible pathways, which are elicited by cells to avoid the introduction of oxidative lesions by hydrogen peroxide. This review summarizes the phenomena of lethal synergism between UV irradiation (254 nm and H2O2, the cross-adaptive response between different classes of genotoxic agents and hydrogen peroxide, and the role of copper ions in the lethal response to H2O2 under low-iron conditions.

  5. Oxygen dependency of one-electron reactions generating ascorbate radicals and hydrogen peroxide from ascorbic acid.

    Science.gov (United States)

    Boatright, William L

    2016-04-01

    The effect of oxygen on the two separate one-electron reactions involved in the oxidation of ascorbic acid was investigated. The rate of ascorbate radical (Asc(-)) formation (and stability) was strongly dependent on the presence of oxygen. A product of ascorbic acid oxidation was measurable levels of hydrogen peroxide, as high as 32.5 μM from 100 μM ascorbic acid. Evidence for a feedback mechanism where hydrogen peroxide generated during the oxidation of ascorbic acid accelerates further oxidation of ascorbic acid is also presented. The second one-electron oxidation reaction of ascorbic acid leading to the disappearance of Asc(-) was also strongly inhibited in samples flushed with argon. In the range of 0.05-1.2 mM ascorbic acid, maximum levels of measurable hydrogen peroxide were achieved with an initial concentration of 0.2 mM ascorbic acid. Hydrogen peroxide generation was greatly diminished at ascorbic acid levels of 0.8 mM or above. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Inorganic compounds and materials as catalysts for oxidations with aqueous hydrogen peroxide

    NARCIS (Netherlands)

    Nardello, veronique; Aubry, Jean-Marie; De Vos, Dirk E.; Neumann, Ronny; Adam, Waldemar; Zhang, Rui; ten Elshof, Johan E.; Witte, Peter T.; Alsters, Paul L.

    2006-01-01

    This paper reviews our work on oxidations with aqueous hydrogen peroxide catalyzed by inorganic catalysts devoid of organic ligands. In the first part of the review, the use of the [WZn3(ZnW9O34)2]12− “sandwich” polyoxometalate as a multi-purpose oxidation catalyst is described. Attention is paid to

  7. Porous layered double hydroxides synthesized using oxygen generated by decomposition of hydrogen peroxide

    NARCIS (Netherlands)

    Gonzalez Rodriguez, P.; de Ruiter, M.P.; Wijnands, Tom; ten Elshof, Johan E.

    2017-01-01

    Porous magnesium-aluminium layered double hydroxides (LDH) were prepared through intercalation and decomposition of hydrogen peroxide (H2O2). This process generates oxygen gas nano-bubbles that pierce holes in the layered structure of the material by local pressure build-up. The decomposition of the

  8. Functionalized Carbon Nanotubes with Gold Nanoparticles to Fabricate a Sensor for Hydrogen Peroxide Determination

    Directory of Open Access Journals (Sweden)

    Halimeh Rajabzade

    2012-01-01

    Full Text Available A highly sensitive electrode was prepared based on gold nanoparticles/nanotubes/ionic liquid for measurement of Hydrogen peroxide. Gold nanoparticles of 20–25 nm were synthesized on a nanotube carbon paste electrode by cyclic voltammetry technique while the coverage was controlled by applied potential and time. The gold nanoparticles were modified to form a monolayer on CNT, followed by decoration with ionic liquid for determination of hydrogen peroxide. The experimental conditions, applied potential and pH, for hydrogen peroxide monitoring were optimized, and hydrogen peroxide was determined amperometrically at 0.3 V vs. SCE at pH 7.0. Electrocatalytic effects of gold deposited CNT were observed with respect to unmodified one. The sensitivity obtained was 5 times higher for modified one. The presence of Au particles in the matrix of CNTs provides an environment for the enhanced electrocatalytic activities. The sensor has a high sensitivity, quickly response to H2O2 and good stability. The synergistic influence of MWNT, Au particles and IL contributes to the excellent performance for the sensor. The sensor responds to H2O2 in the linear range from 0.02 µM to 0.3 mM. The detection limit was down to 0.4 µM when the signal to noise ratio is 3.

  9. Effective oxidation of sulfides to sulfoxides with hydrogen peroxide under transition-metal-free conditions.

    Science.gov (United States)

    Golchoubian, Hamid; Hosseinpoor, Farideh

    2007-03-03

    A "green" highly selective oxidation of organic sulfides to the corresponding sulfoxides was developed using hydrogen peroxide and glacial acetic acid under transition metal-free and mild conditions. The oxidation procedure is very simple and the products are easily isolated in excellent yields (90-99%).

  10. Effective Oxidation of Sulfides to Sulfoxides with Hydrogen Peroxide under Transition-Metal-Free Conditions

    Directory of Open Access Journals (Sweden)

    Farideh Hosseinpoor

    2007-03-01

    Full Text Available A “green” highly selective oxidation of organic sulfides to the corresponding sulfoxides was developed using hydrogen peroxide and glacial acetic acid under transition metal-free and mild conditions. The oxidation procedure is very simple and the products are easily isolated in excellent yields (90-99%.

  11. Portal venous gas emboli after accidental ingestion of concentrated hydrogen peroxide.

    Science.gov (United States)

    Burns, Rebekah A; Schmidt, Suzanne M

    2013-09-01

    Hydrogen peroxide is a common household product. It is clear and odorless making it easy to confuse with water, especially when improperly stored. Concentrated formulations are also available for consumer purchase. We report a case of hydrogen peroxide ingestion in a child and discuss the potential consequences and treatment of such an exposure. A 12-year-old boy accidentally ingested a sip of concentrated hydrogen peroxide. He rapidly developed hematemesis and presented to the Emergency Department. His initial work-up was unremarkable, and his symptoms resolved quickly. However, diffuse gas emboli were found within the portal system on abdominal computed tomography. The child was treated with hyperbaric oxygen therapy and later found to have gastric irritation as well as an ulcer on endoscopy. He recovered fully from the incident. We present this case to increase awareness of the dangers of hydrogen peroxide ingestion in children. Fortunately, the child in this case recovered fully, but emergency physicians should be aware of the potential consequences and therapeutic options. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. Hydrogen peroxide in exhaled air is increased in stable asthmatic children

    NARCIS (Netherlands)

    Q. Jobsis (Quirijn); R.H. Raatgeep (Rolien); P.W.M. Hermans (Peter); J.C. de Jongste (Johan)

    1997-01-01

    textabstractExhaled air condensate provides a noninvasive means of obtaining samples from the lower respiratory tract. Hydrogen peroxide (H2O2) in exhaled air has been proposed as a marker of airway inflammation. We hypothesized that in stable asthmatic children the

  13. Hyperbaric oxygen therapy for the prevention of arterial gas embolism in food grade hydrogen peroxide ingestion.

    Science.gov (United States)

    Hendriksen, Stephen M; Menth, Nicholas L; Westgard, Bjorn C; Cole, Jon B; Walter, Joseph W; Masters, Thomas C; Logue, Christopher J

    2017-05-01

    Food grade hydrogen peroxide ingestion is a relatively rare presentation to the emergency department. There are no defined guidelines at this time regarding the treatment of such exposures, and providers may not be familiar with the potential complications associated with high concentration hydrogen peroxide ingestions. In this case series, we describe four patients who consumed 35% hydrogen peroxide, presented to the emergency department, and were treated with hyperbaric oxygen therapy. Two of the four patients were critically ill requiring intubation. All four patients had evidence on CT or ultrasound of venous gas emboli and intubated patients were treated as if they had an arterial gas embolism since an exam could not be followed. After hyperbaric oxygen therapy each patient was discharged from the hospital neurologically intact with no other associated organ injuries related to vascular gas emboli. Hyperbaric oxygen therapy is an effective treatment for patients with vascular gas emboli after high concentration hydrogen peroxide ingestion. It is the treatment of choice for any impending, suspected, or diagnosed arterial gas embolism. Further research is needed to determine which patients with portal venous gas emboli should be treated with hyperbaric oxygen therapy. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Antitumor effect of synergistic contribution of nitrite and hydrogen peroxide in the plasma activated medium

    Science.gov (United States)

    Kurake, Naoyuki; Tanaka, Hiromasa; Ishikawa, Kenji; Nakamura, Kae; Kajiyama, Hiroaki; Kikkawa, Fumiaki; Kondo, Takashi; Mizuno, Masaaki; Takeda, Keigo; Kondo, Hiroki; Sekine, Makoto; Hori, Masaru

    2015-09-01

    Non-equilibrium atmospheric pressure plasmas (NEAPP) have been attracted attention in the noble application of cancer therapy. Although good effects of the Plasma-Activated-Medium (PAM) such as the selective antitumor effect and killing effect for the anticancer agent resistant cells were reported, a mechanism of this effect has not been still clarified yet. In this study, we have investigated a contribution of the reactive nitrogen and oxygen species (RNOS) generated in PAM such as hydrogen peroxide and nitrite. Those species generated in the PAM quantitatively measured by light absorbance of commercial regent. Moreover, viable cell count after cell culture with those RNOS intentionally added medium or PAM were also measured by MTS assay. Our NEAPP source generated hydrogen peroxide and nitrite with the generation ratio of 0.35 μM/s and 9.8 μM/s. In those RNOS, hydrogen peroxide has respective antitumor effect. On the other hands, nitrite has no antitumor effect singly. But, synergistically enhance the antitumor effect of hydrogen peroxide. Moreover, this effect of those RNOS also contribute for the selectively cancer killing effect of PAM.

  15. Major Effect of Hydrogen Peroxide on Bacterioplankton Metabolism in the Northeast Atlantic

    NARCIS (Netherlands)

    Baltar, F.; Reinthaler, T.; Herndl, G.J.; Pinhassi, J.

    2013-01-01

    Reactive oxygen species such as hydrogen peroxide have the potential to alter metabolic rates of marine prokaryotes, ultimately impacting the cycling and bioavailability of nutrients and carbon. We studied the influence of H2O2 on prokaryotic heterotrophic production (PHP) and extracellular

  16. Mouthwashes with hydrogen peroxide are carcinogenic, but are freely indicated on the Internet: warn your patients!

    Science.gov (United States)

    Consolaro, Alberto

    2013-01-01

    It all began in Ancient Egypt where people used to bleach their teeth with antiseptic mouthwashes made of urea from human urine. Teeth harmony is promoted by expression of feelings, communication, a real window of the brain and its content! Tooth bleaching products are medicines, not cosmetics! Mouth washing with hydrogen peroxide is an illogical and dangerous procedure! Hydrogen peroxide must be used in one's mouth only when employed by a dentist who has been properly instructed to protect the mucosa, preventing it from receiving these products. How and for how long these products are going to be used require caution in order to avoid or decrease any adverse effects on the tissues. Many websites instruct people on how to purchase and prepare hydrogen peroxide so that it is used as an antiseptic mouthwash and tooth bleaching agent. Some websites even refer to dentists as "exploiters", accusing them of not instructing patients properly. In this article, we aim at providing evidence and information upon which dentists and assistants may base their thinking as well as their opinion and procedures regarding "the indiscriminate and free use of hydrogen peroxide in the mouth, on teeth and oral mucosa". Those websites, blogs and social network profiles trespass the limits of public trust and should be immediately sued by the government for committing a crime against public health.

  17. Using hydrogen peroxide as a bladder irrigation solution for clot evacuation

    Directory of Open Access Journals (Sweden)

    Mahdi Bagheri

    2017-03-01

    Full Text Available Gross hematuria or macroscopic hematuria is a high risk urologic condition that might occur in different settings. In the case of continued gross hematuria, blood clot size may grow and lead to complete obstruction of urinary outflow. Placement of three-way catheter, continuous bladder irrigation with normal saline, and cystoscopy are conventional treatments. Here we introduce a case with urinary obstruction who did not respond to conventional therapies. A subject of Hodgkin lymphoma with urinary obstruction caused by heavy gross hematuria was presented to emergency department. Three-way catheter was inserted to facilitate urination. However, there was no urinary drainage and bladder was distended. Consequently, 100 ml solution of hydrogen peroxide 0.15% was prepared and administered into the bladder to irrigate and evacuate the clots. A single intravesical infusion of hydrogen peroxide rapidly resolved urinary obstruction and improved patient distress. After administration of hydrogen peroxide solution, blood clots and bloody urine were evacuated successfully. These findings suggest that an intravesical injection of hydrogen peroxide can induce dissolution of blood clots and may be a simple and efficient therapy for urinary obstruction due to gross hematuria.

  18. Epoxidation of Alkenes with Aqueous Hydrogen Peroxide and Quaternary Ammonium Bicarbonate Catalysts

    DEFF Research Database (Denmark)

    Mielby, Jerrik Jørgen; Kegnæs, Søren

    2013-01-01

    A range of solid and liquid catalysts containing bicarbonate anions were synthesised and tested for the epoxidation of alkenes with aqueous hydrogen peroxide. The combination of bicarbonate anions and quaternary ammonium cations opens up for new catalytic systems that can help to overcome...

  19. Electrocatalytic oxidation of hydrogen peroxide by poly (Ni II-teta ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 112; Issue 3. Electrocatalytic oxidation of hydrogen peroxide by poly(NiII-teta) complex modified electrodes. V Ganesan R Ramaraj. Volume 112 Issue 3 June 2000 pp 409-409. Fulltext. Click here to view fulltext PDF. Permanent link:

  20. Effect of hydrogen peroxide and thiourea on fluorescence and tuberization of potato (Solanum tuberosum L.

    Directory of Open Access Journals (Sweden)

    Mani F.

    2012-08-01

    Full Text Available The aim of this study is to determine the effect of hydrogen peroxide and thiourea on potato crop (quantum yield (Fv/ Fm, chlorophyll content, tuber diameter, tuber number and total tuber yield. The concentrations of these two chemicals are hydrogen peroxide: 0, 20, 40, 60 and 80 mM, and thiourea : 0, 250, 500, 750 and 1000 mM. The experiment was conducted in the farm of Chott-Mariem Institute during three months using variety 'Spunta' and arranged in a completely randomized block with three replications. Results show that there is no significant difference in tuber diameter between treatments and among the same treatment. However, tuber yield is significantly increased by 20 % by thiourea (250 mM. Maximum total yield was obtained at this concentration (810 g/plant. In addition, application of thiourea (500 and 750 mM results in a significantly higher number of tubers number (5.7 and 5.2 respectively. In contrast, treatment with hydrogen peroxide brings about similar tuber yields. Although, application of hydrogen peroxide at low concentration (20 mM, decreases chlorophyll content and stresses plants, application of thiourea increases chlorophyll content, and improve quantum yield especially when it is applied at 250 mM.

  1. Mouthwashes with hydrogen peroxide are carcinogenic, but are freely indicated on the internet: warn your patients!

    Directory of Open Access Journals (Sweden)

    Alberto Consolaro

    2013-12-01

    Full Text Available It all began in Ancient Egypt where people used to bleach their teeth with antiseptic mouthwashes made of urea from human urine. Teeth harmony is promoted by expression of feelings, communication, a real window of the brain and its content! Tooth bleaching products are medicines, not cosmetics! Mouth washing with hydrogen peroxide is an illogical and dangerous procedure! Hydrogen peroxide must be used in one's mouth only when employed by a dentist who has been properly instructed to protect the mucosa, preventing it from receiving these products. How and for how long these products are going to be used require caution in order to avoid or decrease any adverse effects on the tissues. Many websites instruct people on how to purchase and prepare hydrogen peroxide so that it is used as an antiseptic mouthwash and tooth bleaching agent. Some websites even refer to dentists as "exploiters", accusing them of not instructing patients properly. In this article, we aim at providing evidence and information upon which dentists and assistants may base their thinking as well as their opinion and procedures regarding "the indiscriminate and free use of hydrogen peroxide in the mouth, on teeth and oral mucosa". Those websites, blogs and social network profiles trespass the limits of public trust and should be immediately sued by the government for committing a crime against public health.

  2. Non-enzymatic hydrogen peroxide sensor based on Co3O4 ...

    Indian Academy of Sciences (India)

    The Co3O4 nanocubes were prepared by using hydrogen peroxide (H2O2) as oxidant, Co(NO3)2. 6H2O as a cobalt source. The products were characterized in detail by multiform techniques: scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The prepared Co3O4 ...

  3. Study of use of different types of hydrogen peroxides (2006-2008).

    Science.gov (United States)

    Vissers, Marc; Van Parys, Pieter; Audenaert, Joachim; Kerger, Pierrot; De Windt, Wim; Dick, Jan; Gobin, Bruno

    2009-01-01

    Hydrogen peroxides are commonly used in greenhouses for cleaning purposes and disinfection of irrigation water systems, i.e., to prevent clogging by duckweed (Lemna minor), algae and other (micro)organisms. This use contains a potential risk of involuntary contact to the plants, e.g., to roots through irrigation or to the plant leaves through accidental droplets (spraying mist). To help growers to maximize disinfection with minimal risks, the efficacy and plant safety of a variety of commercial available peroxide formulations were compared, i.e., pure peroxide products, peroxide products with additives: Ag, performic acid, peracetic acid and sorbitol. Starting from pure (clean and without fertilizers) irrigation water the peroxides with Ag-stabilisers were most stable and most effective for algae prevention. In screenings for the curative effect on algae, duckweed and bacteria the best results were obtained with peroxide formulations with performic acid. In plant safety tests on potted Ficus benjamina, sprays and irrigations above the plants gave no toxicity till 500 ppm a.i.; irrigations below the plants didn't show toxicity but the plant growth was reduced with weekly applications of 2000 ppm a.i. On the contrary several applications were risky on herbaceous plants, sometimes even with very low dosages (12.5 ppm peroxide).

  4. HYDROGEN PEROXIDE PRODUCTION ACTIVITY AND ADHESIVE PROPERTIES OF AEROCOCCI, ISOLATED IN WOMEN

    Directory of Open Access Journals (Sweden)

    Stepanskyi D.O.

    2017-06-01

    Full Text Available Introduction. Antagonistic activity of probiotic microorganisms against other species of bacteria is an important mechanism of their ecology and it is widely used in practice. This activity is inherent in many heme-deficient bacteria, which include aerococci, and can be composed of several components: the production of organic acids, antibiotics, lysozyme, hydrogen peroxide and others. Ability to produce hydrogen peroxide under aerobic conditions and in a state of relative anaerobiosis was established in aerococci. They were divided into strong and weak producers, depending on the amount of peroxides. Lack of data about peroxide-productive ability of aerococci, isolated from the lower genital tract of women, as well as a proven mechanism of hydrogen peroxide excretion in the oxidation of lactic acid, led to need in studying the aerococci hydrogen peroxide production level, to create autobacterial drugs, based on aerococci symbiont strains for sanitation of birth canal. Colonization resistance of the vaginal mucous and normal microflora value depends largely on the degree of adhesion of microbial cells to the mucosal surface. Along with numerous studies of lactobacilli adhesive properties to the vaginal epithelium, there are no data on the adsorption capacity of aerococci to the vaginal epithelial cells. Material and methods. 18 aerococci resident strains and 1 museum strain were explored in total. Presence and quantity of autosymbiont aerococci content in different parts of the birth tract (cervical canal, vagina, external genitalia skin (EGS and perineum was studied in 44 healthy women. Isolation and identification of aerococci from the women body was conducted by the method, taking into account growth on selective indicator medium, growth and biochemical activity in environments with selenium and tellurium salts, lactate oxidase and superoxide dismutase activity. Hydrogen peroxide was determined by iodometric method. Hydrogen peroxide

  5. Flow injection analysis of organic peroxide explosives using acid degradation and chemiluminescent detection of released hydrogen peroxide.

    Science.gov (United States)

    Mahbub, Parvez; Zakaria, Philip; Guijt, Rosanne; Macka, Mirek; Dicinoski, Greg; Breadmore, Michael; Nesterenko, Pavel N

    2015-10-01

    The applicability of acid degradation of organic peroxides into hydrogen peroxide in a pneumatically driven flow injection system with chemiluminescence reaction with luminol and Cu(2+) as a catalyst (FIA-CL) was investigated for the fast and sensitive detection of organic peroxide explosives (OPEs). The target OPEs included hexamethylene triperoxide diamine (HMTD), triacetone triperoxide (TATP) and methylethyl ketone peroxide (MEKP). Under optimised conditions maximum degradations of 70% and 54% for TATP and HMTD, respectively were achieved at 162 µL min(-1), and 9% degradation for MEKP at 180 µL min(-1). Flow rates were precisely controlled in this single source pneumatic pressure driven multi-channel FIA system by model experiments on mixing of easily detectable component solutions. The linear range for detection of TATP, HMTD and H2O2 was 1-200 µM (r(2)=0.98-0.99) at both flow rates, while that for MEKP was 20-200 µM (r(2)=0.97) at 180 µL min(-1). The detection limits (LODs) obtained were 0.5 µM for TATP, HMTD and H2O2 and 10 µM for MEKP. The detection times varied from 1.5 to 3 min in this FIA-CL system. Whilst the LOD for H2O2 was comparable with those reported by other investigators, the LODs and analysis times for TATP and HMTD were superior, and significantly, this is the first time the detection of MEKP has been reported by FIA-CL. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Hydrogen peroxide modification enhances the ability of biochar (hydrochar) produced from hydrothermal carbonization of peanut hull to remove aqueous heavy metals: Batch and column tests

    Science.gov (United States)

    Experimental and modeling investigations were conducted to examine the effect of hydrogen peroxide treatment on hydrothermally produced biochar (hydrochar) from peanut hull to remove aqueous heavy metals. Characterization measurements showed that hydrogen peroxide modification increased the oxygen-c...

  7. Evaluation of Novel Process Indicators for Rapid Monitoring of Hydrogen Peroxide Decontamination Processes.

    Science.gov (United States)

    McLeod, N P; Clifford, M; Sutton, J M

    2017-01-01

    Geobacillus stearothermophilus spores on stainless steel discs are routinely used as biological indicators for the validation of hydrogen peroxide bio-decontamination processes. Given ongoing concerns about the reliability and response time of biological indicators, we explored the potential for an enzyme-based approach to decontamination process evaluation. Thermostable adenylate kinase enzyme was coated onto a solid support and exposed to hydrogen peroxide vapour, in parallel with standard commercial 6-log biological indicators, during a series of vapour-phase hydrogen peroxide cycles in a flexible film isolator. The exposed biological indicators were enumerated to define the degree of kill at different time intervals and the results compared to the thermostable adenylate kinase values, as determined by measuring adenosine triphosphate produced by residual active enzyme. Both biological indicators and the thermostable adenylate kinase indicators exhibited a biphasic inactivation profile during the process. There was significant variance between individual cycles, with some cycles showing complete inactivation of the biological indicators to the limit of detection of the assay, within 6 min, whereas biological indicators in some cycles were inactivated at a time greater than 12 min. The log-kill of the biological indicators at intermediate time points were plotted and compared to the fully quantifiable measurements derived from the thermostable adenylate kinase indicators at the same time points. The results demonstrated very similar inactivation profiles for the enzyme and for the biological indicators, thus it was possible to define a relationship between relative light units measurement and biological indicator kill. This indicates that it is possible to use thermostable adenylate kinase measurement as a direct measure of vapour-phase hydrogen peroxide bio-decontamination performance, expressed in terms of log reduction. Because thermostable adenylate kinase

  8. Hydrogen peroxide homeostasis: activation of plant catalase by calcium/calmodulin

    Science.gov (United States)

    Yang, T.; Poovaiah, B. W.

    2002-01-01

    Environmental stimuli such as UV, pathogen attack, and gravity can induce rapid changes in hydrogen peroxide (H(2)O(2)) levels, leading to a variety of physiological responses in plants. Catalase, which is involved in the degradation of H(2)O(2) into water and oxygen, is the major H(2)O(2)-scavenging enzyme in all aerobic organisms. A close interaction exists between intracellular H(2)O(2) and cytosolic calcium in response to biotic and abiotic stresses. Studies indicate that an increase in cytosolic calcium boosts the generation of H(2)O(2). Here we report that calmodulin (CaM), a ubiquitous calcium-binding protein, binds to and activates some plant catalases in the presence of calcium, but calcium/CaM does not have any effect on bacterial, fungal, bovine, or human catalase. These results document that calcium/CaM can down-regulate H(2)O(2) levels in plants by stimulating the catalytic activity of plant catalase. Furthermore, these results provide evidence indicating that calcium has dual functions in regulating H(2)O(2) homeostasis, which in turn influences redox signaling in response to environmental signals in plants.

  9. The impact of iron on the bleaching efficacy of hydrogen peroxide in liquid whey systems.

    Science.gov (United States)

    Jervis, Suzanne M; Drake, MaryAnne

    2013-02-01

    Whey is a value-added product that is utilized in many food and beverage applications for its nutritional and functional properties. Whey and whey products are generally utilized in dried ingredient applications. One of the primary sources of whey is from colored Cheddar cheese manufacture that contains the pigment annatto resulting in a characteristic yellow colored Cheddar cheese. The colorant is also present in the liquid cheese whey and must be bleached so that it can be used in ingredient applications without imparting a color. Hydrogen peroxide and benzoyl peroxide are 2 commercially approved chemical bleaching agents for liquid whey. Concerns regarding bleaching efficacy, off-flavor development, and functionality changes have been previously reported for whey bleached with hydrogen peroxide and benzoyl peroxide. It is very important for the dairy industry to understand how bleaching can impact flavor and functionality of dried ingredients. Currently, the precise mechanisms of off-flavor development and functionality changes are not entirely understood. Iron reactions in a bleached liquid whey system may play a key role. Reactions between iron and hydrogen peroxide have been widely studied since the reaction between these 2 relatively stable species can cause great destruction in biological and chemical systems. The actual mechanism of the reaction of iron with hydrogen peroxide has been a controversy in the chemistry and biological community. The precise mechanism for a given reaction can vary greatly based upon the concentration of reactants, temperature, pH, and addition of biological material. In this review, some hypotheses for the mechanisms of iron reactions that may occur in fluid whey that may impact bleaching efficacy, off-flavor development, and changes in functionality are presented. Cheese whey is bleached to remove residual carotenoid cheese colorant. Concerns regarding bleaching efficacy, off-flavor development, and functionality changes have

  10. Distinctive Oxidative Stress Responses to Hydrogen Peroxide in Sulfate Reducing Bacteria Desulfovibrio vulgaris Hildenborough

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Aifen; He, Zhili; Redding, A.M.; Mukhopadhyay, Aindrila; Hemme, Christopher L.; Joachimiak, Marcin P.; Bender, Kelly S.; Keasling, Jay D.; Stahl, David A.; Fields, Matthew W.; Hazen, Terry C.; Arkin, Adam P.; Wall, Judy D.; Zhou, Jizhong

    2009-01-01

    Response of Desulfovibrio vulgaris Hildenborough to hydrogen peroxide (H2O2, 1 mM) was investigated with transcriptomic, proteomic and genetic approaches. Microarray data demonstrated that gene expression was extensively affected by H2O2 with the response peaking at 120 min after H2O2 treatment. Genes affected include those involved with energy production, sulfate reduction, ribosomal structure and translation, H2O2 scavenging, posttranslational modification and DNA repair as evidenced by gene coexpression networks generated via a random matrix-theory based approach. Data from this study support the hypothesis that both PerR and Fur play important roles in H2O2-induced oxidative stress response. First, both PerR and Fur regulon genes were significantly up-regulated. Second, predicted PerR regulon genes ahpC and rbr2 were derepressedin Delta PerR and Delta Fur mutants and induction of neither gene was observed in both Delta PerR and Delta Fur when challenged with peroxide, suggesting possible overlap of these regulons. Third, both Delta PerR and Delta Fur appeared to be more tolerant of H2O2 as measured by optical density. Forth, proteomics data suggested de-repression of Fur during the oxidative stress response. In terms of the intracellular enzymatic H2O2 scavenging, gene expression data suggested that Rdl and Rbr2 may play major roles in the detoxification of H2O2. In addition, induction of thioredoxin reductase and thioredoxin appeared to be independent of PerR and Fur. Considering all data together, D. vulgaris employed a distinctive stress resistance mechanism to defend against increased cellular H2O2, and the temporal gene expression changes were consistent with the slowdown of cell growth at the onset of oxidative stress.

  11. Environmentally acceptable effect of hydrogen peroxide on cave "lamp-flora", calcite speleothems and limestones.

    Science.gov (United States)

    Faimon, Jirí; Stelcl, Jindrich; Kubesová, Svatava; Zimák, Jirí

    2003-01-01

    Mosses, algae, and cyanobacteria (lamp-flora) colonize illuminated areas in show caves. This biota is commonly removed by a sodium hypochlorite solution. Because chlorine and other deleterious compounds are released into a cave environment during lamp-flora cleansing, hydrogen peroxide was tested as an alternative agent. In a multidisciplinary study conducted in the Kateinská Cave (Moravian Karst, Czech Republic), 12 algae- and cyanobacteria taxons and 19 moss taxons were detected. The threshold hydrogen peroxide concentration for the destruction of this lamp-flora was found to be 15 vol.%. Based on laboratory experiments in stirred batch reactors, the dissolution rates of limestones and calcite speleothems in water were determined as 3.77 x 10-3 and 1.81 x 10-3 mol m-2 h-1, respectively. In the 15% peroxide solution, the limestone and speleothem dissolution rates were one order of magnitude higher, 2.00 x 10-2 and 2.21 x 10-2 mol m-2 h-1, respectively. So, the peroxide solution was recognised to attack carbonates somewhat more aggressively than karst water. In order to prevent the potential corrosion of limestone and speleothems, the reaching of preliminary peroxide saturation with respect to calcite is recommended, for example, by adding of few limestone fragments into the solution at least 10 h prior to its application.

  12. Kinetic study of the reactions between chloramine disinfectants and hydrogen peroxide: temperature dependence and reaction mechanism.

    Science.gov (United States)

    McKay, Garrett; Sjelin, Brittney; Chagnon, Matthew; Ishida, Kenneth P; Mezyk, Stephen P

    2013-09-01

    The temperature-dependent kinetics for the reaction between hydrogen peroxide and chloramine water disinfectants (NH2Cl, NHCl2, and NCl3) have been determined using stopped flow-UV/Vis spectrophotometry. Rate constants for the mono- and dichloramine-peroxide reaction were on the order of 10(-2)M(-1)s(-1) and 10(-5)M(-1)s(-1), respectively. The reaction of trichloramine with peroxide was negligibly slow compared to its thermal and photolytically-induced decomposition. Arrhenius expressions of ln(kH2O2-NH2Cl)=(17.3±1.5)-(51500±3700)/RT and ln(kH2O2-NHCl2)=(18.2±1.9)-(75800±5100)/RT were obtained for the mono- and dichloramine peroxide reaction over the temperature ranges 11.4-37.9 and 35.0-55.0°C, respectively. Both monochloramine and hydrogen peroxide were first-order in the rate-limiting kinetic step and concomitant measurements made using a chloride ion selective electrode showed that the chloride was produced quantitatively. These data will aid water utilities in predicting chloramine concentrations (and thus disinfection potential) throughout the water distribution system. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Transenamel and transdentinal penetration of hydrogen peroxide applied to cracked or microabrasioned enamel.

    Science.gov (United States)

    Briso, A L F; Lima, A P B; Gonçalves, R S; Gallinari, M O; dos Santos, P H

    2014-01-01

    The present study evaluated transenamel and transdentinal penetration of hydrogen peroxide during tooth whitening recognized in altered enamel by the presence of cracks or microabrasion. We used 72 experimental units (n=20) obtained from bovine incisors: GI-sound enamel; GII-teeth showing visible enamel cracks (4 mm to 5.7 mm in length); and GIII-microabrasioned enamel. The 12 remaining specimens were used to analyze the enamel surface morphology using scanning electron microscopy. The specimens were cylindrical and 5.7 mm in diameter and 3.5 mm thick. A product based on 35% hydrogen peroxide was used for bleaching, following the manufacturer's recommendations for use. To quantify the H2O2 penetration, the specimens were placed in artificial pulp chambers containing an acetate buffer solution. After bleaching, the solution was collected and adequately proportioned with leucocrystal violet, peroxidase enzyme, and deionized water. The resulting solution was evaluated using ultraviolet visible reflectance spectrophotometer equipment. The data were analyzed by analysis of variance (ANOVA) and Fisher's PLSD at a significance level of 0.05, and significant differences in the penetration of peroxide in different substrate conditions were observed (pMicroabrasion and the presence of cracks in the enamel make this substrate more susceptible to penetration of hydrogen peroxide during in-office whitening.

  14. Understanding the mechanism of DNA deactivation in ion therapy of cancer cells: hydrogen peroxide action*

    Science.gov (United States)

    Piatnytskyi, Dmytro V.; Zdorevskyi, Oleksiy O.; Perepelytsya, Sergiy M.; Volkov, Sergey N.

    2015-11-01

    Changes in the medium of biological cells under ion beam irradiation has been considered as a possible cause of cell function disruption in the living body. The interaction of hydrogen peroxide, a long-lived molecular product of water radiolysis, with active sites of DNA macromolecule was studied, and the formation of stable DNA-peroxide complexes was considered. The phosphate groups of the macromolecule backbone were picked out among the atomic groups of DNA double helix as a probable target for interaction with hydrogen peroxide molecules. Complexes consisting of combinations including: the DNA phosphate group, H2O2 and H2O molecules, and Na+ counterion, were considered. The counterions have been taken into consideration insofar as under the natural conditions they neutralise DNA sugar-phosphate backbone. The energy of the complexes have been determined by considering the electrostatic and the Van der Waals interactions within the framework of atom-atom potential functions. As a result, the stability of various configurations of molecular complexes was estimated. It was shown that DNA phosphate groups and counterions can form stable complexes with hydrogen peroxide molecules, which are as stable as the complexes with water molecules. It has been demonstrated that the formation of stable complexes of H2O2-Na+-PO4- may be detected experimentally by observing specific vibrations in the low-frequency Raman spectra. The interaction of H2O2 molecule with phosphate group of the double helix backbone can disrupt DNA biological function and induce the deactivation of the cell genetic apparatus. Thus, the production of hydrogen peroxide molecules in the nucleus of living cells can be considered as an additional mechanism by which high-energy ion beams destroy tumour cells during ion beam therapy. Contribution to the Topical Issue "COST Action Nano-IBCT: Nano-scale Processes Behind Ion-Beam Cancer Therapy", edited by Andrey Solov'yov, Nigel Mason, Gustavo García, Eugene

  15. Uranium stripping from tri-n-butyl phosphate by hydrogen peroxide solutions

    OpenAIRE

    Smirnov, A. L.; Skripchenko, S. Y.; Rychkov, V. N.; Pastukhov, A. M.; Shtutsa, M. G.

    2013-01-01

    The processes of uranium stripping from 30% tri-n-butyl phosphate (TBP) in "odorless" kerosene by H2O2 solutions both with and without NH4OH added were investigated in the temperature range of 20-50 C and with a volumetric ratio of 1 between the organic and aqueous phases. The uranium was selectively precipitated in the form of uranium peroxide during stripping from the organic phase by hydrogen peroxide. The stripping of uranium increased with increasing H2O2 content, increasing temperature ...

  16. Electrocatalytic synthesis of hydrogen peroxide on Au-Pd nanoparticles: From fundamentals to continuous production

    Science.gov (United States)

    Pizzutilo, Enrico; Kasian, Olga; Choi, Chang Hyuck; Cherevko, Serhiy; Hutchings, Graham J.; Mayrhofer, Karl J. J.; Freakley, Simon J.

    2017-09-01

    The electrochemical synthesis of hydrogen peroxide (H2O2) represents a promising alternative to the anthraquinone process, as it combines on-site chemical and electrical production. The design of selective electrocatalysts is challenging and is commonly based on the alloying of elements to generate a synergistic effect and increase activity. In the present work, we report the electrochemical activity of Au-Pd nanoparticles immobilized directly onto an electrode as a model to study H2O2 electrochemical synthesis from fundamentals to continuous production. The impact of composition on the oxygen reduction reaction (ORR), the selectivity, as well as the peroxide reduction and oxidation reactions (PROR) are studied.

  17. Vital tooth whitening with a novel hydrogen peroxide strip system: design, kinetics, and clinical response.

    Science.gov (United States)

    Sagel, P A; Odioso, L L; McMillan, D A; Gerlach, R W

    2000-01-01

    For many years, at-home whitening has been used with great success and produces some of the most satisfying results of all dental procedures. Historically, the most common procedure used was a custom-fabricated tray loaded with a 10% carbamide peroxide gel that was worn overnight. Today, many manufacturers offer higher concentrations (15% and 20% carbamide peroxide) for faster results. Regardless of the peroxide concentration used, the custom tray delivery system has remained essentially the same. Recently, a trayless whitening system was developed that does not require any prefabrication or gel loading. The new delivery system is a thin, conformable strip precoated with an adhesive hydrogen peroxide gel. Each preloaded strip is presented on a backing liner. To use the strip, it is peeled off of the backing liner and applied to the facial surfaces of the anterior teeth. Each strip is worn for 30 minutes, removed, and discarded. The strip holds the gel in place for sufficient time to allow the peroxide to intrinsically and extrinsically whiten the teeth. The highly flexible strips conform intimately to the tooth surface and provide a uniform, controlled application of the peroxide gel.

  18. Facile one-step electrochemical deposition of copper nanoparticles and reduced graphene oxide as nonenzymatic hydrogen peroxide sensor

    Science.gov (United States)

    Moozarm Nia, Pooria; Woi, Pei Meng; Alias, Yatimah

    2017-08-01

    For several decades, hydrogen peroxide has exhibited to be an extremely significant analyte as an intermediate in several biological devices as well as in many industrial systems. A straightforward and novel one-step technique was employed to develop a sensitive non-enzymatic hydrogen peroxide (H2O2) sensor by simultaneous electrodeposition of copper nanoparticles (CuNPs) and reduced graphene oxide (rGO). The electroreduction performance of the CuNPs-rGO for hydrogen peroxide detection was studied by cyclic voltammetry (CV) and chronoamperometry (AMP) methods The CuNPs-rGO showed a synergistic effect of reduced graphene oxide and copper nanoparticles towards the electroreduction of hydrogen peroxide, indicating high reduction current. At detection potential of -0.2 V, the CuNPs-rGO sensor demonstrated a wide linear range up to 18 mM with a detection limit of 0.601 mM (S/N = 3). Furthermore, with addition of hydrogen peroxide, the sensor responded very quickly (<3 s). The CuNPs-rGO presents high selectivity, sensitivity, stability and fast amperometric sensing towards hydrogen peroxide which makes it favorable for the development of non-enzymatic hydrogen peroxide sensor.

  19. Hydrogen peroxide and the evolution of oxygenic photosynthesis

    Science.gov (United States)

    McKay, C. P.; Hartman, H.

    1991-05-01

    The early atmosphere of the Earth is considered to have been reducing (H2 rich) or neutral (CO2-N2). The present atmosphere by contrast is highly oxidizing (20% O2). The source of this oxygen is generally agreed to have been oxygenic photosynthesis, whereby organisms use water as the electron donor in the production of organic matter, liberating oxygen into the atmosphere. A major question in the evolution of life is how oxygenic photosynthesis could have evolved under anoxic conditions — and also when this capability evolved. It seems unlikely that water would be employed as the electron donor in anoxic environments that were rich in reducing agents such as ferrous or sulfide ions which could play that role. The abiotic production of atmospheric oxidants could have provided a mechanism by which locally oxidizing conditions were sustained within spatially confined habitats thus removing the available reductants and forcing photosynthetic organisms to utilize water as the electron donor. We suggest that atmospheric H2O2 played the key role in inducing oxygenic photosynthesis because as peroxide increased in a local environment, organisms would not only be faced with a loss of reductant, but they would also be pressed to develop the biochemical apparatus (e.g., catalase) that would ultimately be needed to protect against the products of oxygenic photosynthesis. This scenario allows for the early evolution of oxygenic photosynthesis while global conditions were still anaerobic.

  20. Partial oxidation of n-hexadecane through decomposition of hydrogen peroxide in supercritical water

    KAUST Repository

    Alshammari, Y.M.

    2015-01-01

    © 2014 The Institution of Chemical Engineers. This work reports the experimental analysis of partial oxidation of n-hexadecane under supercritical water conditions. A novel reactor flow system was developed which allows for total decomposition of hydrogen peroxide in a separate reactor followed partial oxidation of n-hexadecane in a gasification reactor instead of having both reactions in one reactor. The kinetics of hydrothermal decomposition of hydrogen peroxide was studied in order to confirm its full conversion into water and oxygen under the desired partial oxidation conditions, and the kinetic data were found in a good agreement with previously reported literature. The gas yield and gasification efficiency were investigated under different operating parameters. Furthermore, the profile of C-C/C=C ratio was studied which showed the favourable conditions for maximising yields of n-alkanes via hydrogenation of their corresponding 1-alkenes. Enhanced hydrogenation of 1-alkenes was observed at higher O/C ratios and higher residence times, shown by the increase in the C-C/C=C ratio to more than unity, while increasing the temperature has shown much less effect on the C-C/C=C ratio at the current experimental conditions. In addition, GC-MS analysis of liquid samples revealed the formation of heavy oxygenated compounds which may suggest a new addition reaction to account for their formation under the current experimental conditions. Results show new promising routes for hydrogen production with in situ hydrogenation of heavy hydrocarbons in a supercritical water reactor.

  1. Normal Platelet Integrin Function in Mice Lacking Hydrogen Peroxide-Induced Clone-5 (Hic-5.

    Directory of Open Access Journals (Sweden)

    Michael Popp

    Full Text Available Integrin αIIbβ3 plays a central role in the adhesion and aggregation of platelets and thus is essential for hemostasis and thrombosis. Integrin activation requires the transmission of a signal from the small cytoplasmic tails of the α or β subunit to the large extracellular domains resulting in conformational changes of the extracellular domains to enable ligand binding. Hydrogen peroxide-inducible clone-5 (Hic-5, a member of the paxillin family, serves as a focal adhesion adaptor protein associated with αIIbβ3 at its cytoplasmic tails. Previous studies suggested Hic-5 as a novel regulator of integrin αIIbβ3 activation and platelet aggregation in mice. To assess this in more detail, we generated Hic-5-null mice and analyzed activation and aggregation of their platelets in vitro and in vivo. Surprisingly, lack of Hic-5 had no detectable effect on platelet integrin activation and function in vitro and in vivo under all tested conditions. These results indicate that Hic-5 is dispensable for integrin αIIbβ3 activation and consequently for arterial thrombosis and hemostasis in mice.

  2. Hydrogen peroxide (H2O2) controls axon pathfinding during zebrafish development.

    Science.gov (United States)

    Gauron, Carole; Meda, Francesca; Dupont, Edmond; Albadri, Shahad; Quenech'Du, Nicole; Ipendey, Eliane; Volovitch, Michel; Del Bene, Filippo; Joliot, Alain; Rampon, Christine; Vriz, Sophie

    2016-06-15

    It is now becoming evident that hydrogen peroxide (H2O2), which is constantly produced by nearly all cells, contributes to bona fide physiological processes. However, little is known regarding the distribution and functions of H2O2 during embryonic development. To address this question, we used a dedicated genetic sensor and revealed a highly dynamic spatio-temporal pattern of H2O2 levels during zebrafish morphogenesis. The highest H2O2 levels are observed during somitogenesis and organogenesis, and these levels gradually decrease in the mature tissues. Biochemical and pharmacological approaches revealed that H2O2 distribution is mainly controlled by its enzymatic degradation. Here we show that H2O2 is enriched in different regions of the developing brain and demonstrate that it participates to axonal guidance. Retinal ganglion cell axonal projections are impaired upon H2O2 depletion and this defect is rescued by H2O2 or ectopic activation of the Hedgehog pathway. We further show that ex vivo, H2O2 directly modifies Hedgehog secretion. We propose that physiological levels of H2O2 regulate RGCs axonal growth through the modulation of Hedgehog pathway. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Hydrogen peroxide stimulates the active transport of serotonin into human platelets

    Energy Technology Data Exchange (ETDEWEB)

    Bosin, T.R. (Indiana Univ., Bloomington (United States))

    1991-03-11

    The effect of hydrogen peroxide on the active transport of serotonin (5-HT) by human platelets was investigated. Platelets were exposed to either a single dose of H{sub 2}O{sub 2} or to H{sub 2}O{sub 2} generated by the glucose/glucose oxidase or xanthine/xanthine oxidase enzyme systems. H{sub 2}{sub 2} produced a rapid, dose-dependent and time-dependent increase in 5-HT transport which was maximal after a 2 min incubation and decreased with continued incubation. Catalase completely prevented H{sub 2}O{sub 2}-induced stimulation and fluoxetine totally blocked 5-HT uptake into stimulated platelets. The glucose/glucose oxidase and the xanthine/xanthine oxidase generating systems produced a similar response to that of H{sub 2}O{sub 2}. In the xanthine/xanthine oxidase system, superoxide dismutase failed to alter the stimulation, while catalase effectively prevented the response. The kinetics of 5-HT transport indicated that H{sub 2}O{sub 2} treatment did not alter the K{sub m} of 5-HT transport but significantly increased the maximal rate of 5-HT transport. These data demonstrated that exposure of human platelets to H{sub 2}O{sub 2} resulted in a stimulation of the active transport of 5-HT and suggested that H{sub 2}O{sub 2} may function to regulate this process.

  4. Aquaporin-3 mediates hydrogen peroxide-dependent responses to environmental stress in colonic epithelia.

    Science.gov (United States)

    Thiagarajah, Jay R; Chang, Jeffrey; Goettel, Jeremy A; Verkman, Alan S; Lencer, Wayne I

    2017-01-17

    The colonic epithelium provides an essential barrier against the environment that is critical for protecting the body and controlling inflammation. In response to injury or gut microbes, colonic epithelial cells produce extracellular hydrogen peroxide (H2O2), which acts as a potent signaling molecule affecting barrier function and host defense. In humans, impaired regulation of H2O2 in the intestine has been associated with early-onset inflammatory bowel disease and colon cancer. Here, we show that signal transduction by H2O2 depends on entry into the cell by transit through aquaporin-3 (AQP3), a plasma membrane H2O2-conducting channel. In response to injury, AQP3-depleted colonic epithelial cells showed defective lamellipodia, focal adhesions, and repair after wounding, along with impaired H2O2 responses after exposure to the intestinal pathogen Citrobacter rodentium Correspondingly, AQP3-/- mice showed impaired healing of superficial wounds in the colon and impaired mucosal innate immune responses against C. rodentium infection, manifested by reduced crypt hyperplasia, reduced epithelial expression of IL-6 and TNF-α, and impaired bacterial clearance. These results elucidate the signaling mechanism of extracellular H2O2 in the colonic epithelium and implicate AQP3 in innate immunity at mucosal surfaces.

  5. Protective Effects of Costunolide against Hydrogen Peroxide-Induced Injury in PC12 Cells

    Directory of Open Access Journals (Sweden)

    Chong-Un Cheong

    2016-07-01

    Full Text Available Oxidative stress-mediated cellular injury has been considered as a major cause of neurodegenerative diseases including Alzheimer’s and Parkinson’s diseases. The scavenging of reactive oxygen species (ROS mediated by antioxidants may be a potential strategy for retarding the diseases’ progression. Costunolide (CS is a well-known sesquiterpene lactone, used as a popular herbal remedy, which possesses anti-inflammatory and antioxidant activity. This study aimed to investigate the protective role of CS against the cytotoxicity induced by hydrogen peroxide (H2O2 and to elucidate potential protective mechanisms in PC12 cells. The results showed that the treatment of PC12 cells with CS prior to H2O2 exposure effectively increased the cell viability. Furthermore, it decreased the intracellular ROS, stabilized the mitochondria membrane potential (MMP, and reduced apoptosis-related protein such as caspase 3. In addition, CS treatment attenuated the cell injury by H2O2 through the inhibition of phosphorylation of p38 and the extracellular signal-regulated kinase (ERK. These results demonstrated that CS is promising as a potential therapeutic candidate for neurodegenerative diseases resulting from oxidative damage and further research on this topic should be encouraged.

  6. Hyper, a Hydrogen Peroxide Sensor, Indicates the Sensitivity of the Arabidopsis Root Elongation Zone to Aluminum Treatment

    Directory of Open Access Journals (Sweden)

    Alejandra Hernández-Barrera

    2015-01-01

    Full Text Available Emerging evidence indicates that some reactive oxygen species (ROS, such as the superoxide anion radical and hydrogen peroxide (H2O2, are central regulators of plant responses to biotic and abiotic stresses. Thus, the cellular levels of ROS are thought to be tightly regulated by an efficient and elaborate pro- and antioxidant system that modulates the production and scavenging of ROS. Until recently, studies of ROS in plant cells have been limited to biochemical assays and the use of fluorescent probes; however, the irreversible oxidation of these fluorescent probes makes it impossible to visualize dynamic changes in ROS levels. In this work, we describe the use of Hyper, a recently developed live cell probe for H2O2 measurements in living cells, to monitor oxidative stress in Arabidopsis roots subjected to aluminum treatment. Hyper consists of a circularly permuted YFP (cpYFP inserted into the regulatory domain of the Escherichia coli hydrogen peroxide-binding protein (OxyR, and is a H2O2-specific ratiometric, and therefore quantitative, probe that can be expressed in plant and animal cells. Now we demonstrate that H2O2 levels drop sharply in the elongation zone of roots treated with aluminum. This response could contribute to root growth arrest and provides evidence that H2O2 is involved in early Al sensing.

  7. Sterilization of hydrogen peroxide resistant bacterial spores with stabilized chlorine dioxide.

    Science.gov (United States)

    Friedline, Anthony; Zachariah, Malcolm; Middaugh, Amy; Heiser, Matt; Khanna, Neeraj; Vaishampayan, Parag; Rice, Charles V

    2015-01-01

    Bacillus pumilus SAFR-032 spores isolated from a clean room environment are known to exhibit enhanced resistance to peroxide, desiccation, UV radiation and chemical disinfection than other spore-forming bacteria. The survival of B. pumilus SAFR-032 spores to standard clean room sterilization practices requires development of more stringent disinfection agents. Here, we report the effects of a stabilized chlorine dioxide-based biocidal agent against spores of B. pumilus SAFR-032 and Bacillus subtilis ATCC 6051. Viability was determined via CFU measurement after exposure. Chlorine dioxide demonstrated efficacy towards sterilization of spores of B. pumilus SAFR-032 equivalent or better than exposure to hydrogen peroxide. These results indicate efficacy of chlorine dioxide delivered through a stabilized chlorine dioxide product as a means of sterilization of peroxide- and UV-resistant spores.

  8. Antibacterial Properties and Mechanism of Activity of a Novel Silver-Stabilized Hydrogen Peroxide.

    Directory of Open Access Journals (Sweden)

    Nancy L Martin

    Full Text Available Huwa-San peroxide (hydrogen peroxide; HSP is a NSF Standard 60 (maximum 8 mg/L(-1 new generation peroxide stabilized with ionic silver suitable for continuous disinfection of potable water. Experiments were undertaken to examine the mechanism of HSP against planktonic and biofilm cultures of indicator bacterial strains. Contact/kill time (CT relationships that achieve effective control were explored to determine the potential utility in primary disinfection. Inhibitory assays were conducted using both nutrient rich media and a medium based on synthetic wastewater. Assays were compared for exposures to three disinfectants (HSP, laboratory grade hydrogen peroxide (HP and sodium hypochlorite at concentrations of 20 ppm (therefore at 2.5 and 5 times the NSF limit for HP and sodium hypochlorite, respectively and at pH 7.0 and 8.5 in dechlorinated tap water. HSP was found to be more or equally effective as hypochlorite or HP. Results from CT assays comparing HSP and HP at different bacterial concentrations with neutralization of residual peroxide with catalase suggested that at a high bacterial concentration HSP, but not HP, was protected from catalase degradation possibly through sequestration by bacterial cells. Consistent with this hypothesis, at a low bacterial cell density residual HSP was more effectively neutralized as less HSP was associated with bacteria and therefore accessible to catalase. Silver in HSP may facilitate this association through electrostatic interactions at the cell surface. This was supported by experiments where the addition of mono (K(+ and divalent (Ca(+2 cations (0.005-0.05M reduced the killing efficacy of HSP but not HP. Experiments designed to distinguish any inhibitory effect of silver from that of peroxide in HSP were carried out by monitoring the metabolic activity of established P. aeruginosa PAO1 biofilms. Concentrations of 70-500 ppm HSP had a pronounced effect on metabolic activity while the equivalent

  9. Effects of Martian Surface Materials on the Thermal Decomposition of Hydrogen Peroxide

    Science.gov (United States)

    Dame, Rudger H.; Archer, Paul Douglas; Hogancamp, Joanna C.

    2017-10-01

    While hydrogen peroxide (H2O2) has been detected in the martian atmosphere, it has not been detected in surface materials. Since the Viking lander mission, we have sent instruments to Mars with the capability to detect H2O2. The Sample Analysis at Mars (SAM) instrument onboard the Curiosity Rover and Thermal and Evolved Gas Analyzer (TEGA) instrument on the Phoenix lander both detected water and oxygen releases from analyzed sediments but whether or not peroxide could be the source of these gases has not been investigated. We are investigating the possible presence of H2O2 in martian materials by analyzing Mars-relevant minerals that have been mixed with hydrogen peroxide using lab instruments configured as analogs to Mars mission instruments.The object of this research is to use lab instruments to find the effects of Mars analog minerals on hydrogen peroxide gas release temperatures, specifically gas releases of water and oxygen and also determine the effect of the peroxide on the minerals. Data that we get from the lab can then be compared to the data collected from Mars.The minerals hematite, siderite, San Carlos olivine, magnetite and nontronite were chosen as our Mars analog minerals. ~20 mg of analog Mars minerals with 5µl of 50% H2O2, and were either run immediately or placed in a sealed tube for 2, 4, or 9 days to look for changes over time with two reps being done at each time step to determine repeatability. Each sample was heated from -60 °C to 500 °C at 20 °C/min and the evolved gases were monitored with a mass spectrometer. Each sample was also analyzed with an X-ray diffraction instrument to look for changes in mineralogy.Preliminary results show three potential outcomes: 1) peroxide has no effect on the sample (e.g., hematite), 2) the mineral is unaffected but catalyzes peroxide decomposition (magnetite, siderite), or 3) peroxide alters the mineral (pyrrhotite, San Carlos olivine).

  10. Effects of Martian Surface Materials on the Thermal Decomposition of Hydrogen Peroxide

    Science.gov (United States)

    Archer, P. D., Jr.

    2017-01-01

    While hydrogen peroxide (H2O2) has been detected in the martian atmosphere, it has not been detected in surface materials. Since the Viking lander mission, we have sent instruments to Mars with the capability to detect H2O2. The Sample Analysis at Mars (SAM) instrument onboard the Curiosity Rover and Thermal and Evolved Gas Analyzer (TEGA) instrument on the Phoenix lander both detected water and oxygen releases from analyzed sediments but whether or not peroxide could be the source of these gases has not been investigated. We are investigating the possible presence of H2O2 in martian materials by analyzing Mars-relevant minerals that have been mixed with hydrogen peroxide using lab instruments configured as analogs to Mars mission instruments. The object of this research is to use lab instruments to find the effects of Mars analog minerals on hydrogen peroxide gas release temperatures, specifically gas releases of water and oxygen and also determine the effect of the peroxide on the minerals. Data that we get from the lab can then be compared to the data collected from Mars. The minerals hematite, siderite, San Carlos olivine, magnetite and nontronite were chosen as our Mars analog minerals. 20 mg of analog Mars minerals with 5µl of 50% H2O2, and were either run immediately or placed in a sealed tube for 2, 4, or 9 days to look for changes over time with two reps being done at each time step to determine repeatability. Each sample was heated from -60 degC to 500 degC at 20 degC/min and the evolved gases were monitored with a mass spectrometer. Each sample was also analyzed with an X-ray diffraction instrument to look for changes in mineralogy. Preliminary results show three potential outcomes: 1) peroxide has no effect on the sample (e.g., hematite), 2) the mineral is unaffected but catalyzes peroxide decomposition (magnetite, siderite), or 3) peroxide alters the mineral (pyrrhotite, San Carlos olivine).

  11. Sensory and Functionality Differences of Whey Protein Isolate Bleached by Hydrogen or Benzoyl Peroxide.

    Science.gov (United States)

    Smith, Tucker J; Foegeding, E Allen; Drake, MaryAnne

    2015-10-01

    Whey protein is a highly functional food ingredient used in a wide variety of applications. A large portion of fluid whey produced in the United States is derived from Cheddar cheese manufacture and contains annatto (norbixin), and therefore must be bleached. The objective of this study was to compare sensory and functionality differences between whey protein isolate (WPI) bleached by benzoyl peroxide (BP) or hydrogen peroxide (HP). HP and BP bleached WPI and unbleached controls were manufactured in triplicate. Descriptive sensory analysis and gas chromatography-mass spectrometry were conducted to determine flavor differences between treatments. Functionality differences were evaluated by measurement of foam stability, protein solubility, SDS-PAGE, and effect of NaCl concentration on gelation relative to an unbleached control. HP bleached WPI had higher concentrations of lipid oxidation and sulfur containing volatile compounds than both BP and unbleached WPI (P < 0.05). HP bleached WPI was characterized by high aroma intensity, cardboard, cabbage, and fatty flavors, while BP bleached WPI was differentiated by low bitter taste. Overrun and yield stress were not different among WPI (P < 0.05). Soluble protein loss at pH 4.6 of WPI decreased by bleaching with either hydrogen peroxide or benzoyl peroxide (P < 0.05), and the heat stability of WPI was also distinct among WPI (P < 0.05). SDS PAGE results suggested that bleaching of whey with either BP or HP resulted in protein degradation, which likely contributed to functionality differences. These results demonstrate that bleaching has flavor effects as well as effects on many of the functionality characteristics of whey proteins. Whey protein isolate (WPI) is often used for its functional properties, but the effect of oxidative bleaching chemicals on the functional properties of WPI is not known. This study identifies the effects of hydrogen peroxide and benzoyl peroxide on functional and flavor characteristics of WPI

  12. Can hydrogen peroxide and quercetin improve production of ...

    African Journals Online (AJOL)

    SAM

    2014-07-09

    Jul 9, 2014 ... However, rooting of tree species by cuttings may be hampered by several factors, such as the cutting position, the age of the donor plant and pos- sible treatments with indole butyric acid (IBA) (Hartmann et al., 2002). Hormones and plant growth regulators, such as syn- thetic auxins (IBA) play complex roles ...

  13. Electrocatalysis of hydrogen peroxide reactions on perovskite oxides: experiment versus kinetic modeling.

    Science.gov (United States)

    Poux, T; Bonnefont, A; Ryabova, A; Kéranguéven, G; Tsirlina, G A; Savinova, E R

    2014-07-21

    Hydrogen peroxide has been identified as a stable intermediate of the electrochemical oxygen reduction reaction on various electrodes including metal, metal oxide and carbon materials. In this article we study the hydrogen peroxide oxidation and reduction reactions in alkaline medium using a rotating disc electrode (RDE) method on oxides of the perovskite family (LaCoO3, LaMnO3 and La0.8Sr0.2MnO3) which are considered as promising electrocatalytic materials for the cathode of liquid and solid alkaline fuel cells. The experimental findings, such as the higher activity of Mn-compared to that of Co-perovskites, the shape of RDE curves, and the influence of the H2O2 concentration, are rationalized with the help of a microkinetic model.

  14. Electrochemical determination of hydrogen peroxide at glassy carbon electrode modified with palladium nanoparticles

    Directory of Open Access Journals (Sweden)

    Kitte Addisu Shimeles

    2013-01-01

    Full Text Available We report here the modification of glassy carbon electrode (GCE with palladium nanoparticles and palladium film. The response to hydrogen peroxide on the modified electrode was examined using cyclic voltammetry and amperometry (at -0.2 V vs Ag/AgCl reference electrode in the phosphate buffer solution pH 7.4. The palladium film and palladium nanoparticle modified GCE showed a linear response to hydrogen peroxide in the concentration range between 10 μM to 14 mM and 1 μM to 14 mM with detection limit of 6.79 μM and 0.33 μM, respectively.

  15. Compatibility Studies of Hydrogen Peroxide and a New Hypergolic Fuel Blend

    Science.gov (United States)

    Baldridge, Jennifer; Villegas, Yvonne

    2002-01-01

    Several preliminary materials compatibility studies have been conducted to determine the practicality of a new hypergolic fuel system. Hypergolic fuel ignites spontaneously as the oxidizer decomposes and releases energy in the presence of the fuel. The bipropellant system tested consists of high-test hydrogen peroxide (HTP) and a liquid fuel blend consisting of a hydrocarbon fuel, an ignition enhancer and a transition metal catalyst. In order for further testing of the new fuel blend to take place, some basic materials compatibility and HTP decomposition studies must be accomplished. The thermal decomposition rate of HTP was tested using gas evolution and isothermal microcalorimetry (IMC). Materials were analyzed for compatibility with hydrogen peroxide including a study of the affect welding has on stainless steel elemental composition and its relation to HTP decomposition. Compatibility studies of valve materials in the fuel blend were performed to determine the corrosion resistance of the materials.

  16. Antioxidant activity of wines determined by a polarographic assay based on hydrogen peroxide scavenge.

    Science.gov (United States)

    Gorjanović, Stanislava Z; Novaković, Miroslav M; Potkonjak, Nebojsa I; Suznjević, Desanka Z

    2010-04-28

    Antioxidant (AO) activity of various red and white wines of different origin as well as some individual phenolic compounds present in wine has been assessed using a polarographic assay. Direct current polarography has been used to survey hydrogen peroxide scavenge (HPS) upon gradual addition of tested samples. Results expressed as reciprocal value of wine volume required for 50% decrease of anodic limiting current of hydrogen peroxide have been validated through correlation with Folin-Ciocalteau and DPPH assays. All wines exhibit HPS activity analogous with total phenolic content and DPPH scavenge. Reliability and accuracy, low cost, and rapid and direct experimental procedure open a wide area for application of this assay, making it a good alternative to standard, widely accepted AO assays.

  17. Assessment of the efficacy of a low temperature hydrogen peroxide gas plasma sterilization system.

    Science.gov (United States)

    Kyi, M S; Holton, J; Ridgway, G L

    1995-12-01

    The STERRAD 100 sterilization system (Johnson & Johnson Medical Ltd) uses low temperature hydrogen peroxide gas plasma for sterilization of heat labile equipment. The efficacy of the machine was tested by contaminating a standard set of instruments with different organisms and using a filtration method to assess recovery of organisms from the wash fluids of instruments post-sterilization. Experiments were performed under clean (the organism only) and dirty (organism mixed with egg protein) conditions. A parallel study conducted using a 3M STERIVAC ethylene oxide sterilizer could not be completed owing to closure of the ethylene oxide plant. For sterilization of instruments with long and narrow lumens, hydrogen peroxide adaptors are necessary. The STERRAD 100 sterilizer can achieve effective sterilization of heat labile instruments with a reduction of 6 log10 cfu/mL of organisms tested. This method has the advantages over ethylene oxide sterilization of safety, ease of maintenance and no requirement for aeration time.

  18. Enamel susceptibility to red wine staining after 35% hydrogen peroxide bleaching

    Directory of Open Access Journals (Sweden)

    Sandrine Bittencourt Berger

    2008-06-01

    Full Text Available Concern has been expressed regarding the staining of enamel surface by different beverages after bleaching. This study investigated the influence of 35% hydrogen peroxide bleaching agents on enamel surface stained with wine after whitening treatments. Flat and polished bovine enamel surfaces were submitted to two commercially available 35% hydrogen peroxide bleaching agents or kept in 100% humidity, as a control group (n = 10. Specimens of all groups were immersed in red wine for 48 h at 37°C, immediately, 24 h or 1 week after treatments. All specimens were ground into powder and prepared for the spectrophotometric analysis. Data were subjected to two-way analysis of variance and Fisher's PLSD test at 5% significance level. The amount of wine pigments uptake by enamel submitted to bleaching treatments was statistically higher than that of control group, independently of the evaluation time. Results suggested that wine staining susceptibility was increased by bleaching treatments.

  19. Effect of hydrogen peroxide and camellia sinensis extract on reduction of oxygen level in graphene oxide

    Science.gov (United States)

    Celina Selvakumari, J.; Dhanalakshmi, J.; Pathinettam Padiyan, D.

    2016-10-01

    The intention of this work is to reduce the oxygen level in graphene oxide. The reduction process was initiated while preparing graphene oxide using modified Hummer’s method. In this new method, increase in hydrogen peroxide concentration during the preparation process results in the oxygen content reduction. Adding green tea (camellia sinensis) extract with increased hydrogen peroxide results in further reduction of oxygen content and changed the graphene oxide to reduced graphene oxide. The structural and optical properties of the new found reduced graphene oxide was analysed using XRD, FTIR, TEM, Raman and UV-vis spectra. The overall observation reflects that the sp3 carbon network of graphene oxide changed into sp2 carbon lattice of graphene which is very handful in supercapacitor and biosensor fields.

  20. Clinical trial of tooth whitening with 6% hydrogen peroxide whitening strips and two whitening dentifrices.

    Science.gov (United States)

    Yudhira, Rafael; Peumans, Marleen; Barker, Matthew L; Gerlach, Robert W

    2007-09-01

    To compare tooth whitening with 6% hydrogen peroxide whitening strips and two whitening dentifrices in a 12-week randomized controlled trial at a Belgian dental school. After informed consent, 46 healthy adults were randomly assigned to one of three strip + dentifrice treatment groups. Subjects received either 6% hydrogen peroxide whitening strips (Crest Whitestrips) and an anticavity toothpaste (Crest Cavity Protection), placebo strips and a sodium fluoride (NaF) whitening dentifrice (Mentadent Whitening Toothpaste) or placebo strips and a sodium monofluorophosphate (MFP) whitening dentifrice (Rembrandt Low Abrasion Whitening Toothpaste). Strip use (peroxide or placebo) was for 30 minutes, twice daily for 2 weeks, while dentifrice use was at least twice daily for 12 weeks. Efficacy was measured from standardized digital images of the maxillary facial tooth surfaces, while safety was evaluated from oral examination and interview. Treatments were compared after 2 weeks (strip use) and 12 weeks (dentifrice use) using analysis of covariance. All subjects completed the 12-week evaluation. Adjusting for baseline and age, the peroxide strip group had -2.45 Deltab*, 2.39 DeltaL*, and -0.96 Deltaa* at Week 2. Between-group comparisons demonstrated significant (Pwhitening dentifrices. There were no significant (P> 0.18) differences between the whitening dentifrice groups at any timepoints. All treatments were well-tolerated, with minor tooth sensitivity and oral irritation representing the most common findings.

  1. Novel Applications of the Methyltrioxorhenium/Hydrogen Peroxide Catalytic System

    Energy Technology Data Exchange (ETDEWEB)

    Stankovic, Sasa [Iowa State Univ., Ames, IA (United States)

    2000-09-12

    Methylrhenium trioxide (MTO), CH3Re03, was first prepared in 1979. An improved synthetic route to MTO was devised from dirhenium heptoxide and tetramethyltin in the presence of hexafluoro glutaric anhydride was reported by Herrmann in 1992. During the course of research on this dissertation we uncovered other reactions where the presence or absence of pyridine can, in some cases dramatically, affect the reaction outcome. This dissertation consists of four chapters. The first two chapters deal with the ,oxidation of water sensitive olefinic compounds with the hydrogen perox’ide/MTO system. Chapters 111 and IV focus on the oxidation of hydrazones with the same catalytic system. Chapter I has been published in The Journal of Organic Chemistry and Chapter III in Chemical Communications. Chapters II and IV have been submitted for publication in The Journal of Organic Chemistry. Each section is selfcontained with its own equations, tables, figures and references. All of the work in this dissertation was performed by this author.

  2. Facile synthesis of flower like copper oxide and their application to hydrogen peroxide and nitrite sensing

    OpenAIRE

    Zhang Li; Yuan Feifei; Zhang Xiaohu; Yang Liming

    2011-01-01

    Abstract Background The detection of hydrogen peroxide (H2O2) and nitrite ion (NO2-) is of great important in various fields including clinic, food, pharmaceutical and environmental analyses. Compared with many methods that have been developed for the determination of them, the electrochemical detection method has attracted much attention. In recent years, with the development of nanotechnology, many kinds of micro/nano-scale materials have been used in the construction of electrochemical bio...

  3. Hydrogen peroxide and chlorine dioxide against parasite Ichthyophthirius multifiliis (Protozoa, Ciliophora in jundiá fingerlings

    Directory of Open Access Journals (Sweden)

    Natalia da Costa Marchiori

    2017-11-01

    Full Text Available ABSTRACT: Ichthyophthiriasis is a worldwide fish disease with great financial impact on freshwater fish farming due to its associated high mortality rates. Current study assesses the parasiticidal capacity of hydrogen peroxide (H2O2 and chlorine dioxide (ClO2 against the causative agent, Ichthyophthirius multifiliis, in jundiá. Median lethal concentration (LC50, 96h of each chemical agent was established, as well as the minimum inhibitory concentration of hydrogen peroxide for the parasite´s infectious larval phase (theront. Products were tested asynchronously in parasitized fingerlings for short and long baths at the following concentrations and exposure times: 1. Hydrogen peroxide: (T1 continuous bath - 30ppm and (T2 50ppm; (T3 short bath - 150ppm, during 1h and (T4 250ppm during 1h; control group (without any chemical agent. 2. Chlorine dioxide: (T1 continuous bath - 4ppm and (T2 20ppm; (T3 short bath - 200ppm, during 1min; (T4 short bath - 400ppm, during 1min and control group. Data analysis demonstrated a concentration of 82.54ppm of the commercial product (or 24.76ppm of the active chemical agent as LC50, 96h of H2O2 and 38.4ppm product (or 2.68ppm of the active chemical agent for ClO2. Hydrogen peroxide concentration causing 100% mortality rate of theronts in 1h was 25ppm (product, or 7.5ppm of the active chemical agent. At the end of the fourth day of curative experiment, 98% of the animals died by ichthyophthiriasis. No treatment was effective against the parasite.

  4. Low-temperature decontamination with hydrogen peroxide or chlorine dioxide for space applications.

    Science.gov (United States)

    Pottage, T; Macken, S; Giri, K; Walker, J T; Bennett, A M

    2012-06-01

    The currently used microbial decontamination method for spacecraft and components uses dry-heat microbial reduction at temperatures of >110°C for extended periods to prevent the contamination of extraplanetary destinations. This process is effective and reproducible, but it is also long and costly and precludes the use of heat-labile materials. The need for an alternative to dry-heat microbial reduction has been identified by space agencies. Investigations assessing the biological efficacy of two gaseous decontamination technologies, vapor hydrogen peroxide (Steris) and chlorine dioxide (ClorDiSys), were undertaken in a 20-m(3) exposure chamber. Five spore-forming Bacillus spp. were exposed on stainless steel coupons to vaporized hydrogen peroxide and chlorine dioxide gas. Exposure for 20 min to vapor hydrogen peroxide resulted in 6- and 5-log reductions in the recovery of Bacillus atrophaeus and Geobacillus stearothermophilus, respectively. However, in comparison, chlorine dioxide required an exposure period of 60 min to reduce both B. atrophaeus and G. stearothermophilus by 5 logs. Of the three other Bacillus spp. tested, Bacillus thuringiensis proved the most resistant to hydrogen peroxide and chlorine dioxide with D values of 175.4 s and 6.6 h, respectively. Both low-temperature decontamination technologies proved effective at reducing the Bacillus spp. tested within the exposure ranges by over 5 logs, with the exception of B. thuringiensis, which was more resistant to both technologies. These results indicate that a review of the indicator organism choice and loading could provide a more appropriate and realistic challenge for the sterilization procedures used in the space industry.

  5. A head-to-head comparison of hydrogen peroxide vapor and aerosol room decontamination systems.

    Science.gov (United States)

    Holmdahl, T; Lanbeck, P; Wullt, M; Walder, M H

    2011-09-01

    New technologies have emerged in recent years for the disinfection of hospital rooms and equipment that may not be disinfected adequately using conventional methods. There are several hydrogen peroxide-based area decontamination technologies on the market, but no head-to-head studies have been performed. We conducted a head-to-head in vitro comparison of a hydrogen peroxide vapor (HPV) system (Bioquell) and an aerosolized hydrogen peroxide (aHP) system (Sterinis). The tests were conducted in a purpose-built 136-m(3) test room. One HPV generator and 2 aHP machines were used, following recommendations of the manufacturers. Three repeated tests were performed for each system. The microbiological efficacy of the 2 systems was tested using 6-log Tyvek-pouched Geobacillus stearothermophilus biological indicators (BIs). The indicators were placed at 20 locations in the first test and 14 locations in the subsequent 2 tests for each system. All BIs were inactivated for the 3 HPV tests, compared with only 10% in the first aHP test and 79% in the other 2 aHP tests. The peak hydrogen peroxide concentration was 338 ppm for HPV and 160 ppm for aHP. The total cycle time (including aeration) was 3 and 3.5 hours for the 3 HPV tests and the 3 aHP tests, respectively. Monitoring around the perimeter of the enclosure with a handheld sensor during tests of both systems did not identify leakage. One HPV generator was more effective than 2 aHP machines for the inactivation of G. stearothermophilus BIs, and cycle times were faster for the HPV system.

  6. Investigation of Influential Parameters in Deep Oxidative Desulfurization of Dibenzothiophene with Hydrogen Peroxide and Formic Acid

    OpenAIRE

    Alireza Haghighat Mamaghani; Shohreh Fatemi; Mehrdad Asgari

    2013-01-01

    An effective oxidative system consisting of hydrogen peroxide, formic acid, and sulfuric acid followed by an extractive stage were implemented to remove dibenzothiophene in the simulated fuel oil. The results revealed such a great performance in the case of H2O2 in the presence of formic and sulfuric acids that led to the removal of sulfur compounds. Sulfuric acid was employed to increase the acidity of media as well as catalytic activity together with formic acid. The oxidation reaction was ...

  7. Hydrogen peroxide and hydroxyl radical formation by methylene blue in the presence of ascorbic acid

    Energy Technology Data Exchange (ETDEWEB)

    Buettner, G.R.; Doherty, T.P.; Bannister, T.D.

    1984-09-01

    Using ESR we have demonstrated the formation of the ascorbate free radical from sodium ascorbate, methylene blue and light. In oxygen uptake experiments we have observed the production of hydrogen peroxide while spin trapping experiments have revealed the iron catalyzed production of the hydroxyl free radical in this system. The presence of this highly reactive radical suggests that it could be the radical that initiates free radical damage in this photodynamic system. 39 refs.

  8. Urea-hydrogen peroxide prompted the selective and controlled oxidation of thioglycosides into sulfoxides and sulfones.

    Science.gov (United States)

    Singh, Adesh Kumar; Tiwari, Varsha; Mishra, Kunj Bihari; Gupta, Surabhi; Kandasamy, Jeyakumar

    2017-01-01

    A practical method for the selective and controlled oxidation of thioglycosides to corresponding glycosyl sulfoxides and sulfones is reported using urea-hydrogen peroxide (UHP). A wide range of glycosyl sulfoxides are selectively achieved using 1.5 equiv of UHP at 60 °C while corresponding sulfones are achieved using 2.5 equiv of UHP at 80 °C in acetic acid. Remarkably, oxidation susceptible olefin functional groups were found to be stable during the oxidation of sulfide.

  9. Urea–hydrogen peroxide prompted the selective and controlled oxidation of thioglycosides into sulfoxides and sulfones

    OpenAIRE

    Adesh Kumar Singh; Varsha Tiwari; Kunj Bihari Mishra; Surabhi Gupta; Jeyakumar Kandasamy

    2017-01-01

    A practical method for the selective and controlled oxidation of thioglycosides to corresponding glycosyl sulfoxides and sulfones is reported using urea–hydrogen peroxide (UHP). A wide range of glycosyl sulfoxides are selectively achieved using 1.5 equiv of UHP at 60 °C while corresponding sulfones are achieved using 2.5 equiv of UHP at 80 °C in acetic acid. Remarkably, oxidation susceptible olefin functional groups were found to be stable during the oxidation of sulfide.

  10. Urea?hydrogen peroxide prompted the selective and controlled oxidation of thioglycosides into sulfoxides and sulfones

    OpenAIRE

    Singh, Adesh Kumar; Tiwari, Varsha; Mishra, Kunj Bihari; Gupta, Surabhi; Kandasamy, Jeyakumar

    2017-01-01

    A practical method for the selective and controlled oxidation of thioglycosides to corresponding glycosyl sulfoxides and sulfones is reported using urea?hydrogen peroxide (UHP). A wide range of glycosyl sulfoxides are selectively achieved using 1.5 equiv of UHP at 60 ?C while corresponding sulfones are achieved using 2.5 equiv of UHP at 80 ?C in acetic acid. Remarkably, oxidation susceptible olefin functional groups were found to be stable during the oxidation of sulfide.

  11. Sodium perborate usage instead of hydrogen peroxide for the reinforcement of oxygen delignification

    OpenAIRE

    Emrah PEŞMAN; Ersoy Kalyoncu, Evren; Kırcı, Hüseyin

    2010-01-01

    Oxygen has always been an attractive oxidant for the pulp and paper industry due to it being cheap and harmless for the environment. However, it has lower lignin-cellulose selectivity, therefore the degree of delignification achieved at the oxygen stage is ultimately limited by its industrial pulp strength – 45-50% . In this study, to enhance the degree of delignification, the addition ofsodium perborate and hydrogen peroxide at the oxygen stage was examined. At the same active oxygen (approx...

  12. Radicular penetration of hydrogen peroxide during intra-coronal bleaching with various forms of sodium perborate.

    Science.gov (United States)

    Weiger, R; Kuhn, A; Löst, C

    1994-11-01

    The development of external cervical root resorption following internal bleaching of discoloured pulpless teeth is associated with the use of hydrogen peroxide. The aim of the study was to determine radicular penetration of hydrogen peroxide following intracoronal bleaching with various forms of sodium perborate. 63 extracted human incisors were root filled and stained artificially. Standardized cementum defects were created on the mesial and distal aspects of the root directly below the cemento-enamel junction (CEJ). Using the walking bleach technique all teeth were bleached for a 6-day period, with replacement of the bleaching paste after days 1 and 3. Sodium perborate monohydrate (MH), trihydrate (TRH) or tetrahydrate (TH) was mixed with H2O2 or H2O and subsequently placed intracoronally 1 mm below the labial CEJ. The teeth were divided into six groups: I. MH + H2O2(30%) (n = 12); II. TRH + H2O2(30%) (n = 12); III. TH + H2O2(30%) (n = 12); IV. TH + H2O (n = 12); V. TH + H2O, gel (n = 12); VI. no bleaching paste (n = 3). At baseline and at days 1, 3 and 6 the amount of H2O2 taken up from the surrounding medium of each root was indirectly recorded and calculated as p.p.m. Almost all teeth of the experimental groups showed leakage of hydrogen peroxide compared to those of the control group. The radicular penetration of hydrogen peroxide was significantly higher in teeth of groups I and III than in those of groups IV and V (P sodium perborate used.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Chemical colitis caused by hydrogen peroxide enema in a child: case report and literature review

    OpenAIRE

    Lee, Joon Sang; Yoo, Jung Kyung

    2016-01-01

    A 2-year-old girl, previously healthy, was brought to the emergency department because of significant cramping abdominal pain with recurrent hematochezia after an accidental hydrogen peroxide enema (35%, 5 mL) by her caregiver. She was hospitalized to the pediatric department and treated with nothing per mouth, intravenous fluid and parenteral antibiotic therapy. Laboratory, radiologic and endoscopic evaluation was performed during the admission period. She was discharged in a fully recovered...

  14. Two-photon fluorescence imaging of intracellular hydrogen peroxide with chemoselective fluorescent probes

    OpenAIRE

    Guo, Hengchang; Aleyasin, Hossein; Howard, Scott S.; Dickinson, Bryan C.; Lin, Vivian S.; Haskew-Layton, Renee E.; Xu, Chris; Chen, Yu; Ratan, Rajiv R.

    2013-01-01

    Abstract. We present the application of two-photon fluorescence (TPF) imaging to monitor intracellular hydrogen peroxide (H2O2) production in brain cells. For selective imaging of H2O2 over other reactive oxygen species, we employed small-molecule fluorescent probes that utilize a chemoselective boronate deprotection mechanism. Peroxyfluor-6 acetoxymethyl ester detects global cellular H2O2 and mitochondria peroxy yellow 1 detects mitochondrial H2O2. Two-photon absorption cross sections for th...

  15. PROCESS OPTIMIZATION OF TETRA ACETYL ETHYLENE DIAMINE ACTIVATED HYDROGEN PEROXIDE BLEACHING OF POPULUS NIGRA CTMP

    OpenAIRE

    Qiang Zhao; Junwen Pu; Shulei Mao; Guibo Qi

    2010-01-01

    To enhance the bleaching efficiency, the activator of tetra acetyl ethylene diamine (TAED) was used in conventional H2O2 bleaching. The H2O2/TAED bleaching system can accelerate the reaction rate and shorten bleaching time at relative low temperature, which can reduce the production cost. In this research, the process with hydrogen peroxide activated by TAED bleaching of Populus nigra chemi-thermo mechanical pulp was optimized. Suitable bleaching conditions were confirmed as follows: pulp con...

  16. Presence of hydrogen peroxide, a source of hydroxyl radicals, in acid electrolyzed water.

    Directory of Open Access Journals (Sweden)

    Takayuki Mokudai

    Full Text Available BACKGROUND: Acid electrolyzed water (AEW, which is produced through the electrolysis of dilute sodium chloride (NaCl or potassium chloride solution, is used as a disinfectant in various fields because of its potent antimicrobial activity. The hydroxyl radical, an oxygen radical species, is often suggested as a putative active ingredient for AEW antimicrobial activity. METHODOLOGY/PRINCIPAL FINDINGS: The aim of the present study is to detect hydroxyl radicals in AEW. The hydroxyl radicals in AEW prepared under different conditions were determined using an electron spin resonance (ESR technique. A signal from 5,5-dimethyl-1-pyrroline N-oxide (DMPO-OH, an adduct of DMPO and the hydroxyl radical, was detected in AEW prepared by double or triple electrolyses of 1% NaCl but not of 0.1% NaCl solution. Then the presence of hydrogen peroxide as a proposed source of hydroxyl radicals was examined using a combination of ESR and a Fenton reaction. The DMPO-OH signal was clearly detected, even in AEW prepared by single electrolysis of 0.1% NaCl solution, when ferrous sulfate was added to induce a Fenton reaction, indicating the presence of hydrogen peroxide in the AEW. Since sodium formate, a hydroxyl radical scavenger, did not affect the bactericidal activity of AEW, it is concluded that the radical is unlikely to contribute to the antimicrobial activity of AEW, although a small amount of the radical is produced from hydrogen peroxide. Dimethyl sulfoxide, the other hydroxyl radical scavenger used in the present study, canceled the bactericidal activity of AEW, accompanied by complete depletion of free available chlorine, suggesting that hypochlorous acid is probably a major contributor to the antimicrobial activity. CONCLUSIONS: It is strongly suggested that although hydrogen peroxide is present in AEW as a source of hydroxyl radicals, the antimicrobial activity of AEW does not depend on these radicals.

  17. Mesenchymal stem cells restore frataxin expression and increase hydrogen peroxide scavenging enzymes in Friedreich ataxia fibroblasts.

    Directory of Open Access Journals (Sweden)

    Kevin Kemp

    Full Text Available Dramatic advances in recent decades in understanding the genetics of Friedreich ataxia (FRDA--a GAA triplet expansion causing greatly reduced expression of the mitochondrial protein frataxin--have thus far yielded no therapeutic dividend, since there remain no effective treatments that prevent or even slow the inevitable progressive disability in affected individuals. Clinical interventions that restore frataxin expression are attractive therapeutic approaches, as, in theory, it may be possible to re-establish normal function in frataxin deficient cells if frataxin levels are increased above a specific threshold. With this in mind several drugs and cytokines have been tested for their ability to increase frataxin levels. Cell transplantation strategies may provide an alternative approach to this therapeutic aim, and may also offer more widespread cellular protective roles in FRDA. Here we show a direct link between frataxin expression in fibroblasts derived from FRDA patients with both decreased expression of hydrogen peroxide scavenging enzymes and increased sensitivity to hydrogen peroxide-mediated toxicity. We demonstrate that normal human mesenchymal stem cells (MSCs induce both an increase in frataxin gene and protein expression in FRDA fibroblasts via secretion of soluble factors. Finally, we show that exposure to factors produced by human MSCs increases resistance to hydrogen peroxide-mediated toxicity in FRDA fibroblasts through, at least in part, restoring the expression of the hydrogen peroxide scavenging enzymes catalase and glutathione peroxidase 1. These findings suggest, for the first time, that stem cells may increase frataxin levels in FRDA and transplantation of MSCs may offer an effective treatment for these patients.

  18. Measurement of hydrogen peroxide and organic hydroperoxide concentrations during autumn in Beijing, China.

    Science.gov (United States)

    Zhang, Qingyu; Liu, Jiaoyu; He, Youjiang; Yang, Jiaying; Gao, Jian; Liu, Houfeng; Tang, Wei; Chen, Yizhen; Fan, Wenhao; Chen, Xuan; Chai, Fahe; Hatakeyama, Shiro

    2018-02-01

    Gaseous peroxides play important roles in atmospheric chemistry. To understand the pathways of the formation and removal of peroxides, atmospheric peroxide concentrations and their controlling factors were measured from 7:00 to 20:00 in September, October, and November 2013 at a heavily trafficked residential site in Beijing, China, with average concentrations of hydrogen peroxide (H 2 O 2 ) and methyl hydroperoxide (MHP) at 0.55ppb and 0.063ppb, respectively. H 2 O 2 concentrations were higher in the afternoon and lower in the morning and evening, while MHP concentrations did not exhibit a regular diurnal pattern. Both H 2 O 2 and MHP concentrations increased at dusk in most cases. Both peroxides displayed monthly variations with higher concentrations in September. These results suggested that photochemical activity was the main controlling factor on variations of H 2 O 2 concentrations during the measurement period. Increasing concentrations of volatile organic compounds emitted by motor vehicles were important contributors to H 2 O 2 and MHP enrichment. High levels of H 2 O 2 and MHP concentrations which occurred during the measurement period probably resulted from the transport of a polluted air mass with high water vapor content passing over the Bohai Bay, China. Copyright © 2017. Published by Elsevier B.V.

  19. Lignin isolation process from rice husk by alkaline hydrogen peroxide: Lignin and silica extracted

    Science.gov (United States)

    Ma'ruf, Anwar; Pramudono, Bambang; Aryanti, Nita

    2017-03-01

    Biomass is one of abundance resources in the world. Biomass consists of three main materials such as cellulose, hemicelluloses and lignin. Therefore, biomass can be referred to lignocellulosic material. Both the cellulose and hemicelluloses fractions are polymers of sugars, and thereby a potential source of fermentable sugars, or other processes that convert sugars into products. Lignin is a polymer compound which contains of phenolic compounds. Rice husk is one of biomass, which has high contain of lignin. Rice husk has special characteristics because of silica content. The aim of this paper is to analyze lignin and silica extracted during lignin isolation process of rice husk using alkaline hydrogen peroxide. Three main variables such as solvent/solid ratio, concentration of hydrogen peroxide and pH of the mixture are studied. The optimum conditions for lignin isolation are at solvent/solid ratio 9:1 ml/gr, hydrogen peroxide concentration of 1.5%v and pH of the mixture of 11.

  20. A Spectrometric Method for Hydrogen Peroxide Concentration Measurement with a Reusable and Cost-Efficient Sensor

    Directory of Open Access Journals (Sweden)

    Cheng-Chih Hsu

    2015-10-01

    Full Text Available In this study we developed a low cost sensor for measuring the concentration of hydrogen peroxide (H2O2 in liquids utilizing a spectrometric method. The sensor was tested using various concentrations of a peroxidase enzyme immobilized on a glass substrate. H2O2 can be catalyzed by peroxidase and converted into water and oxygen. The reagent 4-amino-phenazone takes up oxygen together with phenol to form a colored product that has absorption peaks at 510 nm and 450 nm. The transmission intensity is strongly related to the hydrogen peroxide concentration, so can be used for quantitative analysis. The measurement range for hydrogen peroxide is from 5 × 10−5% to 1 × 10−3% (0.5 ppm to 10 ppm and the results show high linearity. This device can achieve a sensitivity and resolution of 41,400 (photon count/% and 3.49 × 10−5% (0.35 ppm, respectively. The response time of the sensor is less than 3 min and the sensor can be reused for 10 applications with similar performance.

  1. Hydrogen-peroxide-modified egg albumen for transparent and flexible resistive switching memory

    Science.gov (United States)

    Zhou, Guangdong; Yao, Yanqing; Lu, Zhisong; Yang, Xiude; Han, Juanjuan; Wang, Gang; Rao, Xi; Li, Ping; Liu, Qian; Song, Qunliang

    2017-10-01

    Egg albumen is modified by hydrogen peroxide with concentrations of 5%, 10%, 15% and 30% at room temperature. Compared with devices without modification, a memory cell of Ag/10% H2O2-egg albumen/indium tin oxide exhibits obviously enhanced resistive switching memory behavior with a resistance ratio of 104, self-healing switching endurance for 900 cycles and a prolonged retention time for a 104 s @ 200 mV reading voltage after being bent 103 times. The breakage of massive protein chains occurs followed by the recombination of new protein chain networks due to the oxidation of amidogen and the synthesis of disulfide during the hydrogen peroxide modifying egg albumen. Ions such as Fe3+, Na+, K+, which are surrounded by protein chains, are exposed to the outside of protein chains to generate a series of traps during the egg albumen degeneration process. According to the fitting results of the double logarithm I-V curves and the current-sensing atomic force microscopy (CS-AFM) images of the ON and OFF states, the charge transfer from one trap center to its neighboring trap center is responsible for the resistive switching memory phenomena. The results of our work indicate that hydrogen- peroxide-modified egg albumen could open up a new avenue of biomaterial application in nanoelectronic systems.

  2. Inhibition of hydrogen peroxide induced injuring on human skin fibroblast by Ulva prolifera polysaccharide.

    Science.gov (United States)

    Cai, Chuner; Guo, Ziye; Yang, Yayun; Geng, Zhonglei; Tang, Langlang; Zhao, Minglin; Qiu, Yuyan; Chen, Yifan; He, Peimin

    2016-10-01

    Ulva prolifera can protect human skin fibroblast from being injured by hydrogen peroxide. This work studied the composition of Ulva prolifera polysaccharide and identified its physicochemical properties. The results showed that the cell proliferation of 0.5mg/mL crude polysaccharide was 154.4% of that in negative control group. Moreover, ROS detection indices, including DCFH-DA, GSH-PX, MDA and CAT, indicated that crude polysaccharide could improve cellular ability to scavenge free radical and decrease the injury on human skin fibroblast by hydrogen peroxide. In purified polysaccharide, the activity of fraction P1-1 was the highest, with 174.6% of that in negative control group. The average molecular weight of P1-1 was 137kD with 18.0% of sulfate content. This work showed the inhibition of hydrogen peroxide induced injuries on human skin fibroblast by Ulva prolifera polysaccharide, which may further evaluate the application of U. prolifera on cosmetics. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Sonochemical and hydrodynamic cavitation reactors for laccase/hydrogen peroxide cotton bleaching.

    Science.gov (United States)

    Gonçalves, Idalina; Martins, Madalena; Loureiro, Ana; Gomes, Andreia; Cavaco-Paulo, Artur; Silva, Carla

    2014-03-01

    The main goal of this work is to develop a novel and environmental-friendly technology for cotton bleaching with reduced processing costs. This work exploits a combined laccase-hydrogen peroxide process assisted by ultrasound. For this purpose, specific reactors were studied, namely ultrasonic power generator type K8 (850 kHz) and ultrasonic bath equipment Ultrasonic cleaner USC600TH (45 kHz). The optimal operating conditions for bleaching were chosen considering the highest levels of hydroxyl radical production and the lowest energy input. The capacity to produce hydroxyl radicals by hydrodynamic cavitation was also assessed in two homogenizers, EmulsiFlex®-C3 and APV-2000. Laccase nanoemulsions were produced by high pressure homogenization using BSA (bovine serum albumin) as emulsifier. The bleaching efficiency of these formulations was tested and the results showed higher whiteness values when compared to free laccase. The combination of laccase-hydrogen peroxide process with ultrasound energy produced higher whiteness levels than those obtained by conventional methods. The amount of hydrogen peroxide was reduced 50% as well as the energy consumption in terms of temperature (reduction of 40 °C) and operating time (reduction of 90 min). Copyright © 2013 Elsevier Inc. All rights reserved.

  4. The disinfection of impression materials by using microwave irradiation and hydrogen peroxide.

    Science.gov (United States)

    Choi, Yu-Ri; Kim, Kyoung-Nam; Kim, Kwang-Mahn

    2014-10-01

    Microwave irradiation and immersion in solutions have been recommended for denture disinfection. However, the effect of dry conditions and impression materials has not been completely evaluated. The purpose of this study was to evaluate the effectiveness of microwave irradiation and hydrogen peroxide for the disinfection of dental impression materials. Specimens (diameter 10 mm, thickness 2 mm) were made with polyvinyl siloxane. Experimental groups were treated with hydrogen peroxide (group H), microwave irradiation (group M), and a combination of both hydrogen peroxide and microwave irradiation (group MH) for 1 minute, 2 minutes, and 3 minutes. The control group was untreated. The total sample size was 120. The specimens were divided into 2 groups, those exposed to Streptococcus mutans and those exposed to Escherichia coli. The disinfection effect and physical properties (contact angle, compatibility with gypsum, strain in compression, tear strength) were evaluated. All 3 groups (H, M, MH) were effective in reducing the number of colony forming units (CFU) per unit volume (mL) for both S mutans and E coli compared with the control. The most significant reduction in the CFU/mL of both bacteria was noted in the MH group and was used to compare either treatment alone (P.05). Microwave irradiation was identified as a useful disinfection method against S mutans and E coli, especially when combined with H2O2, without adversely affecting the physical properties of dental impression materials. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  5. The motivational benefits of a dentifrice containing baking soda and hydrogen peroxide.

    Science.gov (United States)

    Fischman, S L; Kugel, G; Truelove, R B; Nelson, B J; Cancro, L P

    1992-01-01

    Twenty-two family practice dentists, in a large metropolitan area, were recruited to act as independent examiners in a study to evaluate the compliance of their patients to accept a good oral hygiene regimen with the use of a fluoride dentifrice, containing hydrogen peroxide and baking soda, dispensed from a dual dispensing package. To evaluate compliance, the dentists attended an orientation seminar and were trained to assess gingival health using the CPITN periodontal probe. Each dentist evaluated the gingival health status of five to seven of his own patients, initially and after one and three months of product use following hygiene instruction and product assignment. One-hundred and thirty-one patients successfully completed the study. After one month of using the hydrogen peroxide/baking soda toothpaste, the mean reduction in bleeding sites was 53%; at three months the reduction was 62%. The hydrogen peroxide/baking soda dentifrice was well accepted by dentist and patient, and a discernible improvement in oral health of the patients was achieved when the product was used in a conscientious oral hygiene program.

  6. A novel amperometric biosensor based on artichoke (Cynara scolymus L.) tissue homogenate immobilized in gelatin for hydrogen peroxide detection.

    Science.gov (United States)

    Oztürk, G; Ertaş, F N; Akyilmaz, E; Dinçkaya, E; Tural, H

    2004-01-01

    A biosensor for specific determination of hydrogen peroxide was developed by using homogenized artichoke (Cynara scolymus L.) tissue in combination with a dissolved oxygen probe and applied in determination of hydrogen peroxide in milk samples. Artichoke tissue, which has catalase activity, was immobilized with gelatine by means of glutaraldehyde and fixed on a pretreated teflon membrane. The electrode response was maximum when 0.05 M phosphate buffer was used at pH 7.0 and at 30 degrees C. Upon addition of hydrogen peroxide, the electrode gives a linear response in a concentration range of 5.0-50 x 10(-5) M with a response time of 3 min. The method was also applied to the determination of hydrogen peroxide in milk samples.

  7. Antifouling effect of hydrogen peroxide release from enzymatic marine coatings: Exposure testing under equatorial and Mediterranean conditions

    DEFF Research Database (Denmark)

    Olsen, S.M.; Kristensen, J.B.; Laursen, B.S.

    2010-01-01

    Hydrogen peroxide (H2O2) may be considered an environmentally friendly antifouling alternative to common biocides such as Cu2O and various organic compounds. In this work, the efficiency of antifouling coatings releasing hydrogen peroxide via enzyme-mediated conversion of starch, under...... exceeding that of two commercial references over 67 days. The release rate of hydrogen peroxide from the coatings is shown to be greatly influenced by temperature, and therefore the results provided here suggest an antifouling effect that is highly dependent on the environment of the coating....... laboratory assays, the transient hydrogen peroxide release rate from the coatings at different temperatures has been measured. The investigations are used to evaluate the ocean performance of the antifouling coatings. Coatings can be formulated with starch/enzyme 'pigments' in considerable amounts and yet...

  8. The effect of endogenous hydrogen peroxide induced by cold treatment in the improvement of tissue regeneration efficiency

    NARCIS (Netherlands)

    Szechynska-Hebda, M.; Skrzypek, E.; Dabrowska, G.; Wedzony, M.; Lammeren, van A.A.M.

    2012-01-01

    We propose that oxidative stress resulting from an imbalance between generation and scavenging hydrogen peroxide contributes to tissue regeneration efficiency during somatic embryogenesis of hexaploid winter wheat (Triticum aestivum cv. Kamila) and organogenesis of faba bean (Vicia faba ssp. minor

  9. Morpho- Physiological Changes of Hempseed (Cannabis sativa L. Traits as Affected by Seed Priming with Folic Acid and Hydrogen Peroxide

    Directory of Open Access Journals (Sweden)

    Shirin Karbalaye Golizadeh

    2016-03-01

    Full Text Available To evaluate the effects of seed priming of hempseed with folic acid and hydrogen peroxide on some morphological and physiological traits a factorial greenhouse experiment based on randomized complete design with four replications was conducted at Islamic Azad University, Mahabad Branch. Treatments consisted of hydrogen peroxide at five levels (0, 7.5, 15, 22.5, 30 mm/liter as the first factor and the four leveld of folic acid (5, 10, 20, 27 mm/liter as the second factor.Seeds, to be primed, were immersed into solution of folic acid for 24 hours and hydrogen peroxide for 6 hours. The characteristics like chlorophyll a, chlorophyll b, total chlorophyll content, relative water content, plant height, root length, allometric coefficient, plant fresh and dry weights, were measured. Result of analysis of variance showed that the effects of folic acid and hydrogen peroxide on all characters were significant, but the interaction between the two treatments were only significant on relative water content and allometric coefficient. In this study, seed priming with 15 mm/liter of hydrogen peroxide and 5mm folic acid resulted in highest chlorophyll a, chlorophyll b, total chlorophyll contents, plant height, root length, fresh and dry weights. Increasing hydrogen peroxide level above 15mm/liter affected traits negatively. Combinated treatments of 15 mm/liter of hydrogen peroxide and 5 and 10 mm of folic acid resulted in highest relative water content and allometric coefficient, respectively. Based on the results obtained it can be concluded that priming seeds with 15 mm/liter of hydrogen peroxide and 5mm folic acid is recommended to produce proper morphological and physiological traits.

  10. Effect of bleaching teeth with hydrogen peroxide on the morphology, hydrophilicity, and mechanical and tribological properties of the enamel

    OpenAIRE

    Rodrigues, F. T.; Serro, A. P.; Polido, M.; Ramalho, A.; Figueiredo-Pina, C. G.

    2017-01-01

    The tooth whitening process is intended to restore the original color of teeth. It consists of the application of oxidizing agents, including hydrogen peroxide. Although these products considerably improve the color of teeth, their effects on other properties of enamel are not fully understood. This work aimed to study the effects of hydrogen peroxide concentration on hydrophilicity, roughness, morphology, and mechanical and tribological properties of human tooth enamel. Human teeth were subj...

  11. Effects of 15% Carbamide Peroxide and 40% Hydrogen Peroxide on the Microhardness and Color Change of Composite Resins

    Science.gov (United States)

    Kamangar, Sedighe Sadat Hashemi; Kiakojoori, Kiana; Mirzaii, Mansoore; Fard, Mohammad Javad Kharazi

    2014-01-01

    Objective: The aim of this study was to determine the effects of 40% hydrogen peroxide and 15% carbamide peroxide on microhardness and color change of a silorane-based composite resin in comparison with two methacrylate-based composites. Materials and Methods: Fifty-four disc-shaped specimens (A3 shade) were fabricated of Filtek P90 (P90), Filtek Z350XT Enamel (Z350) and Filtek Z250 (Z250) (3MESPE) (n=18). The samples of each composite were randomly divided into three subgroups of 6. The control subgroups were immersed in distilled water; the test groups were exposed to Opalescence Boost (OB) once; and Opalescence PF (OP) (Ultradent) for two weeks. Vickers microhardness testing and a spectrophotometric analysis of the color of samples were performed before and after each intervention. Results: The baseline microhardness of P90 was significantly lower than that of the other two composites (P=0.001), but no difference was found between Z250 and Z350 in this respect (P=0.293). Bleaching treatments significantly decreased the microhardness of Z250 and Z350 (P 0.05). No significant difference was detected between the two types of bleaching (P>0.05). After bleaching with OB, ΔE value was measured to be 3.12(1.97), 3.31(1.84) and 3.7(2.11) for P90, Z250 and Z350, respectively. These values were 5.98(2.42), 4.66(2.85) and 4.90(2.78) after bleaching with OP with no significant difference. Conclusion: Bleaching decreased the microhardness of methacrylate-based but not silorane-based composites. Although no significant differences were found in ΔE of composites, ΔE of all groups did not remain in the clinically acceptable range after bleaching except for P90 after bleaching with 40% H2O2 (ΔE < 3.3). PMID:24910696

  12. Decontamination assessment of Bacillus anthracis, Bacillus subtilis, and Geobacillus stearothermophilus spores on indoor surfaces using a hydrogen peroxide gas generator.

    Science.gov (United States)

    Rogers, J V; Sabourin, C L K; Choi, Y W; Richter, W R; Rudnicki, D C; Riggs, K B; Taylor, M L; Chang, J

    2005-01-01

    To evaluate the decontamination of Bacillus anthracis, Bacillus subtilis, and Geobacillus stearothermophilus spores on indoor surface materials using hydrogen peroxide gas. Bacillus anthracis, B. subtilis, and G. stearothermophilus spores were dried on seven types of indoor surfaces and exposed to > or =1000 ppm hydrogen peroxide gas for 20 min. Hydrogen peroxide exposure significantly decreased viable B. anthracis, B. subtilis, and G. stearothermophilus spores on all test materials except G. stearothermophilus on industrial carpet. Significant differences were observed when comparing the reduction in viable spores of B. anthracis with both surrogates. The effectiveness of gaseous hydrogen peroxide on the growth of biological indicators and spore strips was evaluated in parallel as a qualitative assessment of decontamination. At 1 and 7 days postexposure, decontaminated biological indicators and spore strips exhibited no growth, while the nondecontaminated samples displayed growth. Significant differences in decontamination efficacy of hydrogen peroxide gas on porous and nonporous surfaces were observed when comparing the mean log reduction in B. anthracis spores with B. subtilis and G. stearothermophilus spores. These results provide comparative information for the decontamination of B. anthracis spores with surrogates on indoor surfaces using hydrogen peroxide gas.

  13. Use of clinical bleaching with 35% hydrogen peroxide in esthetic improvement of fluorotic human incisors in vivo.

    Science.gov (United States)

    Shanbhag, Raghavendra; Veena, R; Nanjannawar, Girish; Patil, Jaykumar; Hugar, Santosh; Vagrali, Hemanth

    2013-03-01

    The aim of the study was to evaluate esthetic improvement with the use of 35% hydrogen peroxide clinical bleaching as related to the different grades of enamel fluorosis in vivo and to study adverse effect of clinical bleaching with 35% hydrogen peroxide on teeth and gingiva. A total of 60 children of different grades of fluorosis were included in the study. With 35% hydrogen peroxide-based dual activated bleaching system, in-office vital teeth bleaching was carried out for each subject. Clinical evaluation for improvement in esthetics, effect on teeth and gingiva were performed for each child during preoperative, immediate postoperative and later 6 months postoperative period. For evaluation and comparison, all the collected data were subjected to statistical analysis. Although in all the subjects, partial shade relapse was seen over a period of time, good homogeneous and esthetic results were seen in very mild and mild cases. A total of 35% hydrogen peroxide in-office bleaching has no adverse effect on teeth and gingiva. Comparing all the three groups who participated in the study, 35% hydrogen peroxide in-office bleaching seems to be very effective in very mild and mild forms of fluorosis. In very mild and mild forms of fluorosis, in-office vital tooth bleaching with 35% hydrogen peroxide is the most conservative and effective approach in esthetic improvement.

  14. The Inhibitory Effect of PIK-75 on Inflammatory Mediator Response Induced by Hydrogen Peroxide in Feline Esophageal Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Jun Yeong Jeong

    2014-01-01

    Full Text Available Isoform-selective inhibitors of phosphoinositide 3-kinase (PI3K activation have an anti-inflammatory effect by reducing proinflammatory cytokines. Cultured feline esophageal epithelial cells (EEC of passages 3~4 were treated with hydrogen peroxide and PIK-75. The cell viability was measured by a MTT incorporation assay. The distribution of PI3K isoforms, p-Akt, IL-1β, and IL-8 was inferred from Western blots. The release of IL-6 was determined by ELISA. The cell morphology was not considerably different from nontreated cells if the cells were pretreated with PIK-75 and treated with 300 μM hydrogen peroxide. The density of p110α of PI3K was increased, but that of other types was not affected after the treatment with hydrogen peroxide. The density of p-Akt, when the cells were exposed to PIK-75 and hydrogen peroxide, was diminished dose dependently more than that of hydrogen peroxide treatment only. The decrease of p-Akt showed an inhibition of PI3K by PIK-75. PIK-75 dose dependently reduced the expression of IL-1β, IL-8, and the level of IL-6 compared with hydrogen peroxide treatment only. These results suggest evidence that p110α mediates esophageal inflammation and that PIK-75 has an anti-inflammatory effect by reducing proinflammatory cytokines on feline esophageal epithelial cultured cells.

  15. The effect of hydrogen peroxide solution on SO2 removal in the semidry flue gas desulfurization process.

    Science.gov (United States)

    Zhou, Yuegui; Zhu, Xian; Peng, Jun; Liu, Yaobin; Zhang, Dingwang; Zhang, Mingchuan

    2009-10-15

    The present study attempts to use hydrogen peroxide solution to humidify Ca(OH)(2) particles to enhance the absorption of SO(2) to achieve higher removal efficiency and to solve the valuable reuse of the reaction product in the semidry flue gas desulfurization (FGD) process. Experiments were carried out to examine the effect of various operating parameters including hydrogen peroxide solution concentration, Ca/S molar ratio and approach to adiabatic saturation temperature on SO(2) removal efficiency in a laboratory scale spray reactor. The product samples were analyzed to obtain semi-quantitative measures of mineralogical composition by X-ray diffraction (XRD) with reference intensity ratio (RIR) method and the morphology of the samples was examined by scanning electron microscope (SEM). Compared with spraying water to humidify Ca(OH)(2), SO(2) removal efficiency was improved significantly by spraying hydrogen peroxide solution of 1-3 wt.% to humidify Ca(OH)(2) because hydrogen peroxide solution enhanced the dissolution and absorption rate of SO(2). Moreover, XRD and SEM analyses show that the desulfurization products contain less amount of unreacted Ca(OH)(2) and more amount of stable calcium sulfate with increasing hydrogen peroxide solution concentration. Thus, the process mechanism of the enhanced absorption of SO(2) by spraying hydrogen peroxide solution to humidify Ca(OH)(2) was elucidated on the basis of the experimental results.

  16. COMPARATIVE STUDY OF ANTIBACTERIAL ACTIVITY OF PEROXYDISUCCINIC ACID, HYDROGEN PEROXIDE AND THEIR MIXTURE

    Directory of Open Access Journals (Sweden)

    Blazheyevskiy M.Ye.,

    2016-06-01

    Full Text Available Introduction. It is known that reactive oxygen species (ROS generated in vivo by cell aerobic metabolism cause multiple damage in different cell organelles and kill not only obligate anaerobes and microaerophilles, but also aerobes. ROS generated by phagocytes and representatives of normal microflora are an important component of macroorganism defense from most pathogens, which is explained by their ability to damage different biological structures. ROS have high reactivity and let us use them in vitro as effective biocides. Hydrogen peroxide is widely used in many industries, in particular, in medicine and veterinary as antiseptic and disinfectant agent due to its safety for environment and broad spectrum of antimicrobial activity including spore-forming bacteria. However, in the recent years certain decrease of background sensitivity of microorganisms to hydrogen peroxide and occurrence of resistant strains of pathogenic microorganisms to this agent has been noted. The aim of this work is to carry out a comparative study of antimicrobial activity of hydrogen peroxide, peroxydisuccinic acid (PDSA, monoperoxysuccinic acid (MPSA, and mixture of PDSA and hydrogen peroxide (Н2О2. Materials and methods. The substances of peroxydisuccinic acid (PDSA and monoperoxysuccinic acid (MPSA were prepared by well known methods. The following test-strains were used to assess antimicrobial activity of the agents: Staphylococcus aureus АТСС 25923, Escherichia coli АТСС 25922, Pseudomonas aeruginosa АТСС 27853, Pseudomonas aeruginosa АТСС 9027, Basillus сereus АТСС 10702, Basillus сereus АТСС 96, Basillus subtilis АТСС 6633, Proteus vulgaris ATCC 4636, Candida albicans АТСС 885/653, and Candida albicans АТСС 10231. All disinfectant agents were diluted in distilled water at 40 ºС and stirred. The microbial burden was 2∙109 CFU/ml of the medium, and for kinetic studies 105 CFU/ml of the medium, it was standardizing

  17. A Comparison between Lime and Alkaline Hydrogen Peroxide Pretreatments of Sugarcane Bagasse for Ethanol Production

    Science.gov (United States)

    Rabelo, Sarita C.; Filho, Rubens Maciel; Costa, Aline C.

    Pretreatment procedures of sugarcane bagasse with lime (calcium hydroxide) or alkaline hydrogen peroxide were evaluated and compared. Analyses were performed using 2 × 2 × 2 factorial designs, with pretreatment time, temperature, and lime loading and hydrogen peroxide concentration as factors. The responses evaluated were the yield of total reducing sugars (TRS) and glucose released from pretreated bagasse after enzymatic hydrolysis. Experiments were performed using the bagasse as it comes from an alcohol/ sugar factory and bagasse in the size range of 0.248 to 1.397 mm (12-60 mesh). The results show that when hexoses and pentoses are of interest, lime should be the pretreatment agent chosen, as high TRS yields are obtained for nonscreened bagasse using 0.40 g lime/g dry biomass at 70 °C for 36 h. When the product of interest is glucose, the best results were obtained with lime pretreatment of screened bagasse. However, the results for alkaline peroxide and lime pretreatments of nonscreened bagasse are not very different.

  18. Chemo-enzymatic epoxidation of olefins by carboxylic acid esters and hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Ruesch gen. Klaas, M.; Warwel, S. [Inst. for Biochemistry and Technology of Lipids, H.P. Kaufmanm-Inst., Federal Centre for Cereal, Potato and Lipid Research, Muenster (Germany)

    1998-12-31

    Ethylen and, recently, butadiene can be epoxidized directly with oxygen and for the epoxidation of propylene, the use of heterogeneous transition metals and organic peroxides (Halcon-Process) is the major player. But, beside from those notable exceptions, all other epoxidations, including large ones like the epoxidation of plant oils as PVC-stabilizers (about 200.000 t/year), are carried out with peroxy acids. Because mcpba is far to expensive for most applications, short chain peracids like peracetic acid are used. Being much less stable than mcpba and thus risky handled in large amounts and high concentrations, these peroxy acids were preferably prepared in-situ. However, conventional in-situ formation of peracids has the serious drawback, that a strong acid is necessary to catalyze peroxy acid formation from the carboxylic acid and hydrogen peroxide. The presence of a strong acid in the reaction mixture often results in decreased selectivity because of the formation of undesired by-products by opening of the oxirane ring. Therefore, we propose a new method for epoxidation based on the in-situ preparation of percarboxylic acids from carboxylic acid esters and hydrogen peroxide catalyzed by a commercial, immobilized lipase. (orig.)

  19. Hydrogen peroxide-mediated neuronal cell death induced by an endogenous neurotoxin, 3-hydroxykynurenine.

    Science.gov (United States)

    Okuda, S; Nishiyama, N; Saito, H; Katsuki, H

    1996-10-29

    3-Hydroxykynurenine (3-HK) is a tryptophan metabolite whose level in the brain is markedly elevated under several pathological conditions, including Huntington disease and human immunodeficiency virus infection. Here we demonstrate that micromolar concentrations (1-100 microM) of 3-HK cause cell death in primary neuronal cultures prepared from rat striatum. The neurotoxicity of 3-HK was blocked by catalase and desferrioxamine but not by superoxide dismutase, indicating that the generation of hydrogen peroxide and hydroxyl radical is involved in the toxicity. Measurement of peroxide levels revealed that 3-HK caused intracellular accumulation of peroxide, which was largely attenuated by application of catalase. The peroxide accumulation and cell death caused by 1-10 microM 3-HK were also blocked by pretreatment with allopurinol or oxypurinol, suggesting that endogenous xanthine oxidase activity is involved in exacerbation of 3-HK neurotoxicity. Furthermore, NADPH diaphorase-containing neurons were spared from toxicity of these concentrations of 3-HK, a finding reminiscent of the pathological characteristics of several neurodegenerative disorders such as Huntington disease. These results suggest that 3-HK at pathologically relevant concentrations renders neuronal cells subject to oxidative stress leading to cell death, and therefore that this endogenous compound should be regarded as an important factor in pathogenesis of neurodegenerative disorders.

  20. A respiratory chain controlled signal transduction cascade in the mitochondrial intermembrane space mediates hydrogen peroxide signaling.

    Science.gov (United States)

    Patterson, Heide Christine; Gerbeth, Carolin; Thiru, Prathapan; Vögtle, Nora F; Knoll, Marko; Shahsafaei, Aliakbar; Samocha, Kaitlin E; Huang, Cher X; Harden, Mark Michael; Song, Rui; Chen, Cynthia; Kao, Jennifer; Shi, Jiahai; Salmon, Wendy; Shaul, Yoav D; Stokes, Matthew P; Silva, Jeffrey C; Bell, George W; MacArthur, Daniel G; Ruland, Jürgen; Meisinger, Chris; Lodish, Harvey F

    2015-10-20

    Reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) govern cellular homeostasis by inducing signaling. H2O2 modulates the activity of phosphatases and many other signaling molecules through oxidation of critical cysteine residues, which led to the notion that initiation of ROS signaling is broad and nonspecific, and thus fundamentally distinct from other signaling pathways. Here, we report that H2O2 signaling bears hallmarks of a regular signal transduction cascade. It is controlled by hierarchical signaling events resulting in a focused response as the results place the mitochondrial respiratory chain upstream of tyrosine-protein kinase Lyn, Lyn upstream of tyrosine-protein kinase SYK (Syk), and Syk upstream of numerous targets involved in signaling, transcription, translation, metabolism, and cell cycle regulation. The active mediators of H2O2 signaling colocalize as H2O2 induces mitochondria-associated Lyn and Syk phosphorylation, and a pool of Lyn and Syk reside in the mitochondrial intermembrane space. Finally, the same intermediaries control the signaling response in tissues and species responsive to H2O2 as the respiratory chain, Lyn, and Syk were similarly required for H2O2 signaling in mouse B cells, fibroblasts, and chicken DT40 B cells. Consistent with a broad role, the Syk pathway is coexpressed across tissues, is of early metazoan origin, and displays evidence of evolutionary constraint in the human. These results suggest that H2O2 signaling is under control of a signal transduction pathway that links the respiratory chain to the mitochondrial intermembrane space-localized, ubiquitous, and ancient Syk pathway in hematopoietic and nonhematopoietic cells.

  1. The effects of hydrogen peroxide on the circadian rhythms of Microcystis aeruginosa.

    Directory of Open Access Journals (Sweden)

    Haifeng Qian

    Full Text Available BACKGROUND: The cyanobacterium Microcystis aeruginosa is one of the principal bloom-forming cyanobacteria present in a wide range of freshwater ecosystems. M. aeruginosa produces cyanotoxins, which can harm human and animal health. Many metabolic pathways in M. aeruginosa, including photosynthesis and microcystin synthesis, are controlled by its circadian rhythms. However, whether xenobiotics affect the cyanobacterial circadian system and change its growth, physiology and biochemistry is unknown. We used real-time PCR to study the effect of hydrogen peroxide (H(2O(2 on the expression of clock genes and some circadian genes in M. aeruginosa during the light/dark (LD cycle. RESULTS: The results revealed that H(2O(2 changes the expression patterns of clock genes (kaiA, kaiB, kaiC and sasA and significantly decreases the transcript levels of kaiB, kaiC and sasA. H(2O(2 treatment also decreased the transcription of circadian genes, such as photosynthesis-related genes (psaB, psbD1 and rbcL and microcystin-related genes (mcyA, mcyD and mcyH, and changed their circadian expression patterns. Moreover, the physiological functions of M. aeruginosa, including its growth and microcystin synthesis, were greatly influenced by H(2O(2 treatment during LD. These results indicate that changes in the cyanobacterial circadian system can affect its physiological and metabolic pathways. CONCLUSION: Our findings show that a xenobiotic can change the circadian expression patterns of its clock genes to influence clock-controlled gene regulation, and these influences are evident at the level of cellular physiology.

  2. Hydrogen peroxide priming modulates abiotic oxidative stress tolerance: insights from ROS detoxification and scavenging

    Science.gov (United States)

    Hossain, Mohammad A.; Bhattacharjee, Soumen; Armin, Saed-Moucheshi; Qian, Pingping; Xin, Wang; Li, Hong-Yu; Burritt, David J.; Fujita, Masayuki; Tran, Lam-Son P.

    2015-01-01

    Plants are constantly challenged by various abiotic stresses that negatively affect growth and productivity worldwide. During the course of their evolution, plants have developed sophisticated mechanisms to recognize external signals allowing them to respond appropriately to environmental conditions, although the degree of adjustability or tolerance to specific stresses differs from species to species. Overproduction of reactive oxygen species (ROS; hydrogen peroxide, H2O2; superoxide, O2⋅-; hydroxyl radical, OH⋅ and singlet oxygen, 1O2) is enhanced under abiotic and/or biotic stresses, which can cause oxidative damage to plant macromolecules and cell structures, leading to inhibition of plant growth and development, or to death. Among the various ROS, freely diffusible and relatively long-lived H2O2 acts as a central player in stress signal transduction pathways. These pathways can then activate multiple acclamatory responses that reinforce resistance to various abiotic and biotic stressors. To utilize H2O2 as a signaling molecule, non-toxic levels must be maintained in a delicate balancing act between H2O2 production and scavenging. Several recent studies have demonstrated that the H2O2-priming can enhance abiotic stress tolerance by modulating ROS detoxification and by regulating multiple stress-responsive pathways and gene expression. Despite the importance of the H2O2-priming, little is known about how this process improves the tolerance of plants to stress. Understanding the mechanisms of H2O2-priming-induced abiotic stress tolerance will be valuable for identifying biotechnological strategies to improve abiotic stress tolerance in crop plants. This review is an overview of our current knowledge of the possible mechanisms associated with H2O2-induced abiotic oxidative stress tolerance in plants, with special reference to antioxidant metabolism. PMID:26136756

  3. Hydrogen peroxide priming modulates abiotic oxidative stress tolerance: insights from ROS detoxification and scavenging

    Directory of Open Access Journals (Sweden)

    Mohammad A. Hossain

    2015-06-01

    Full Text Available Plants are constantly challenged by various abiotic stresses that negatively affect growth and productivity worldwide. During the course of their evolution, plants have developed sophisticated mechanisms to recognize external signals allowing them to respond appropriately to environmental conditions, although the degree of adjustability or tolerance to specific stresses differs from species to species. Overproduction of reactive oxygen species (ROS (hydrogen peroxide, H2O2; superoxide, O2ˉ˙; hydroxyl radical, OH. and singlet oxygen, 1O2 is enhanced under abiotic and/or biotic stresses, which can cause oxidative damage to plant macromolecules and cell structures, leading to inhibition of plant growth and development, or to death. Among the various ROS, freely diffusible and relatively long-lived H2O2 acts as a central player in stress signal transduction pathways. These pathways can then activate multiple acclamatory responses that reinforce resistance to various abiotic and biotic stressors. To utilize H2O2 as a signaling molecule, non-toxic levels must be maintained in a delicate balancing act between H2O2 production and scavenging. Several recent studies have demonstrated that the H2O2-priming can enhance abiotic stress tolerance by modulating ROS detoxification and by regulating multiple stress-responsive pathways and gene expression. Despite the importance of the H2O2-priming, little is known about how this process improves the tolerance of plants to stress. Understanding the mechanisms of H2O2-priming-induced abiotic stress tolerance will be valuable for identifying biotechnological strategies to improve abiotic stress tolerance in crop plants. This review is an overview of our current knowledge of the possible mechanisms associated with H2O2-induced abiotic oxidative stress tolerance in plants, with special reference to antioxidant metabolism.

  4. Hydrogen peroxide priming modulates abiotic oxidative stress tolerance: insights from ROS detoxification and scavenging.

    Science.gov (United States)

    Hossain, Mohammad A; Bhattacharjee, Soumen; Armin, Saed-Moucheshi; Qian, Pingping; Xin, Wang; Li, Hong-Yu; Burritt, David J; Fujita, Masayuki; Tran, Lam-Son P

    2015-01-01

    Plants are constantly challenged by various abiotic stresses that negatively affect growth and productivity worldwide. During the course of their evolution, plants have developed sophisticated mechanisms to recognize external signals allowing them to respond appropriately to environmental conditions, although the degree of adjustability or tolerance to specific stresses differs from species to species. Overproduction of reactive oxygen species (ROS; hydrogen peroxide, H2O2; superoxide, [Formula: see text]; hydroxyl radical, OH(⋅) and singlet oxygen, (1)O2) is enhanced under abiotic and/or biotic stresses, which can cause oxidative damage to plant macromolecules and cell structures, leading to inhibition of plant growth and development, or to death. Among the various ROS, freely diffusible and relatively long-lived H2O2 acts as a central player in stress signal transduction pathways. These pathways can then activate multiple acclamatory responses that reinforce resistance to various abiotic and biotic stressors. To utilize H2O2 as a signaling molecule, non-toxic levels must be maintained in a delicate balancing act between H2O2 production and scavenging. Several recent studies have demonstrated that the H2O2-priming can enhance abiotic stress tolerance by modulating ROS detoxification and by regulating multiple stress-responsive pathways and gene expression. Despite the importance of the H2O2-priming, little is known about how this process improves the tolerance of plants to stress. Understanding the mechanisms of H2O2-priming-induced abiotic stress tolerance will be valuable for identifying biotechnological strategies to improve abiotic stress tolerance in crop plants. This review is an overview of our current knowledge of the possible mechanisms associated with H2O2-induced abiotic oxidative stress tolerance in plants, with special reference to antioxidant metabolism.

  5. Aquaporin-Mediated Water and Hydrogen Peroxide Transport Is Involved in Normal Human Spermatozoa Functioning

    Directory of Open Access Journals (Sweden)

    Umberto Laforenza

    2016-12-01

    Full Text Available Different aquaporins (AQPs are expressed in human sperm cells and with a different localization. Their function has been related to cell volume control in response to the osmotic changes encountered passing from the epididymal fluid to the cervical mucus or involved in the end stage of cytoplasm removal during sperm maturation. Recently, AQPs have also shown hydrogen peroxide (H2O2 permeability properties. Here, we investigate the expression, localization and functioning of AQPs in human sperm cells with particular attention to their role as peroxiporins in reactive oxygen species (ROS scavenging in both normospermic and sub-fertile human subjects. Western blotting and immunocytochemistry were used to confirm and clarify the AQPs expression and localization. Water and H2O2 permeability was tested by stopped flow light scattering method and by the CM-H2DCFDA (5-(and-6-chloromethyl-2′,7′-dichlorodihydro-fluorescein diacetate, acetyl ester H2O2 fluorescence probe, respectively. AQP3, -7, -8, and -11 proteins were found in human sperm cells and localized in the head (AQP7, in the middle piece (AQP8 and in the tail (AQP3 and -11 in both the plasma membrane and in intracellular structures. Sperm cells showed water and H2O2 permeability which was reversibly inhibited by H2O2, heat stress and the AQP inhibitor HgCl2. Reduced functionality was observed in patients with compromised basal semen parameters. Present findings suggest that AQPs are involved in both volume regulation and ROS elimination. The relationship between sperm number and motility and AQP functioning was also demonstrated.

  6. A high-throughput microtiter plate based method for the determination of peracetic acid and hydrogen peroxide.

    Directory of Open Access Journals (Sweden)

    Karson S Putt

    Full Text Available Peracetic acid is gaining usage in numerous industries who have found a myriad of uses for its antimicrobial activity. However, rapid high throughput quantitation methods for peracetic acid and hydrogen peroxide are lacking. Herein, we describe the development of a high-throughput microtiter plate based assay based upon the well known and trusted titration chemical reactions. The adaptation of these titration chemistries to rapid plate based absorbance methods for the sequential determination of hydrogen peroxide specifically and the total amount of peroxides present in solution are described. The results of these methods were compared to those of a standard titration and found to be in good agreement. Additionally, the utility of the developed method is demonstrated through the generation of degradation curves of both peracetic acid and hydrogen peroxide in a mixed solution.

  7. Transcriptomic profiling provides molecular insights into hydrogen peroxide-induced adventitious rooting in mung bean seedlings.

    Science.gov (United States)

    Li, Shi-Weng; Leng, Yan; Shi, Rui-Fang

    2017-02-17

    Hydrogen peroxide (H2O2) has been known to function as a signalling molecule involved in the modulation of various physiological processes in plants. H2O2 has been shown to act as a promoter during adventitious root formation in hypocotyl cuttings. In this study, RNA-Seq was performed to reveal the molecular mechanisms underlying H2O2-induced adventitious rooting. RNA-Seq data revealed that H2O2 treatment greatly increased the numbers of clean reads and expressed genes and abundance of gene expression relative to the water treatment. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses indicated that a profound change in gene function occurred in the 6-h H2O2 treatment and that H2O2 mainly enhanced gene expression levels at the 6-h time point but reduced gene expression levels at the 24-h time point compared with the water treatment. In total, 4579 differentially expressed (2-fold change > 2) unigenes (DEGs), of which 78.3% were up-regulated and 21.7% were down-regulated; 3525 DEGs, of which 64.0% were up-regulated and 36.0% were down-regulated; and 7383 DEGs, of which 40.8% were up-regulated and 59.2% were down-regulated were selected in the 6-h, 24-h, and from 6- to 24-h treatments, respectively. The number of DEGs in the 6-h treatment was 29.9% higher than that in the 24-h treatment. The functions of the most highly regulated genes were associated with stress response, cell redox homeostasis and oxidative stress response, cell wall loosening and modification, metabolic processes, and transcription factors (TFs), as well as plant hormone signalling, including auxin, ethylene, cytokinin, gibberellin, and abscisic acid pathways. Notably, a large number of genes encoding for heat shock proteins (HSPs) and heat shock transcription factors (HSFs) were significantly up-regulated during H2O2 treatments. Furthermore, real-time quantitative PCR (qRT-PCR) results showed that, during H2O2 treatments, the expression levels of

  8. Auxin increases the hydrogen peroxide (H2O2) concentration in tomato (Solanum lycopersicum) root tips while inhibiting root growth.

    Science.gov (United States)

    Ivanchenko, Maria G; den Os, Désirée; Monshausen, Gabriele B; Dubrovsky, Joseph G; Bednárová, Andrea; Krishnan, Natraj

    2013-10-01

    The hormone auxin and reactive oxygen species (ROS) regulate root elongation, but the interactions between the two pathways are not well understood. The aim of this study was to investigate how auxin interacts with ROS in regulating root elongation in tomato, Solanum lycopersicum. Wild-type and auxin-resistant mutant, diageotropica (dgt), of tomato (S. lycopersicum 'Ailsa Craig') were characterized in terms of root apical meristem and elongation zone histology, expression of the cell-cycle marker gene Sl-CycB1;1, accumulation of ROS, response to auxin and hydrogen peroxide (H2O2), and expression of ROS-related mRNAs. The dgt mutant exhibited histological defects in the root apical meristem and elongation zone and displayed a constitutively increased level of hydrogen peroxide (H2O2) in the root tip, part of which was detected in the apoplast. Treatments of wild-type with auxin increased the H2O2 concentration in the root tip in a dose-dependent manner. Auxin and H2O2 elicited similar inhibition of cell elongation while bringing forth differential responses in terms of meristem length and number of cells in the elongation zone. Auxin treatments affected the expression of mRNAs of ROS-scavenging enzymes and less significantly mRNAs related to antioxidant level. The dgt mutation resulted in resistance to both auxin and H2O2 and affected profoundly the expression of mRNAs related to antioxidant level. The results indicate that auxin regulates the level of H2O2 in the root tip, so increasing the auxin level triggers accumulation of H2O2 leading to inhibition of root cell elongation and root growth. The dgt mutation affects this pathway by reducing the auxin responsiveness of tissues and by disrupting the H2O2 homeostasis in the root tip.

  9. On-site applicability of hydrogen peroxide producing microbial electrochemical cells (MECs) coupled with UV in wastewater disinfection study

    Science.gov (United States)

    Background: There is an increased interest in the application of microbial electrochemical cell (MEC) for the recovery of value-added products such as hydrogen gas and hydrogen peroxide (H2O2) from wastewater. H2O2 has strong oxidation capability and produces hydroxyl radicals wh...

  10. ON-SITE APPLICABILITY OF HYDROGEN PEROXIDE PRODUCING MICROBIAL ELECTROCHEMICAL CELLS COUPLED WITH UV IN WASTEWATER DISINFECTION STUDY

    Science.gov (United States)

    There is an increased interest in the application of microbial electrochemical cell (MEC) for the recovery of value-added products such as hydrogen gas and hydrogen peroxide (H2O2) from wastewater. H2O2 has strong oxidation capability and produces hydroxyl radicals when coupled w...

  11. Hydrogen sulfide decreases the plasma lipid peroxidation induced by homocysteine and its thiolactone.

    Science.gov (United States)

    Olas, Beata; Kontek, Bogdan

    2015-06-01

    Hydrogen sulfide (H2S) has been investigated widely in recent years. H2S plays a variety of roles in different biological systems, including cardiovascular system. It is the final product of amino acids metabolism, which contains sulfur-cysteine and homocysteine (Hcy). In human plasma, there are several various forms of homocysteine: free Hcy, protein-bound Hcy (S-linked, and N-linked), and homocysteine thiolactone (HTL). Our previous works have shown that both Hcy in the reduced form and its thiolactone may modify fibrinolysis, coagulation process, and biological activity of blood platelets. Moreover, we have observed that HTL, like its precursor-Hcy stimulated the generation of superoxide anion radicals (O 2 (-•) ) in blood platelets. The aim of our study in vitro was to establish the influence of sodium hydrosulfide (NaHS, as a fast-releasing H2S donor; at tested concentrations: 10-1000 µM) on the plasma lipid peroxidation induced by the reduced Hcy (at final concentrations of 0.01-1 mM) and HTL (at final concentrations of 0.1-1 µM). Our results indicate that 10 and 100 µM NaHS decreased the lipid peroxidation in plasma treated with 1 mM Hcy or 1 µM HTL (when NaHS and Hcy/HTL were added to plasma together). The protective effect of 10 and 100 µM NaHS against the lipid peroxidation in plasma preincubated with 1 mM Hcy or 1 µM HTL was also observed. Considering the data presented in this study, we suggest that the lipid peroxidation (induced by different forms of homocysteine) may be reduced by hydrogen sulfide.

  12. Comparison of protective effect of ascorbic acid on redox and endocannabinoid systems interactions in in vitro cultured human skin fibroblasts exposed to UV radiation and hydrogen peroxide.

    Science.gov (United States)

    Gęgotek, Agnieszka; Bielawska, Katarzyna; Biernacki, Michał; Zaręba, Ilona; Surażyński, Arkadiusz; Skrzydlewska, Elżbieta

    2017-05-01

    The mechanisms of biological activity of commonly used natural compounds are constantly examined. Therefore, the aim of this study was to compare ascorbic acid efficacy in counteracting the consequences of UV and hydrogen peroxide treatment on lipid mediators and their regulative action on antioxidant abilities. Skin fibroblasts exposed to UVA and UVB irradiation, treated with hydrogen peroxide and ascorbic acid. The redox system was estimated through reactive oxygen species (ROS) generation (electron spin resonance spectrometer) and antioxidants level/activity (HPLC/spectrometry) which activity was evaluated by the level of phospholipid metabolites: 4-hydroxynonenal, malondialdehyde, 8-isoprostanes and endocannabinoids (GC/LC-MS) in the human skin fibroblasts. Protein and DNA oxidative modifications were also determined (LC). The expression of nuclear factor erythroid 2-related factor 2 (Nrf2), its activators and inhibitors as well as pro/anti-apoptotic proteins and endocannabinoid receptors was examined (Western blot) and collagen metabolism was evaluated by collagen biosynthesis and prolidase activity (spectrometry). UVA and UVB irradiation and hydrogen peroxide treatment enhanced activity of xanthine and NADPH oxidases resulting in ROS generation as well as diminution of antioxidant phospholipid protection (glutathione peroxidase-glutathione-vitamin E), what led to increased lipid peroxidation and decreased endocannabinoids level. Dysregulation of cannabinoid receptors expression and environment of transcription factor Nrf2 caused apoptosis induction. Ascorbic acid partially prevented ROS generation, antioxidant capacity diminution and endocannabinoid systems disturbances but only slightly protected macromolecules such as phospholipid, protein and DNA against oxidative modifications. However, ascorbic acid significantly prevented decrease in collagen type I biosynthesis. Ascorbic acid in similar degree prevents UV (UVA and UVB) and hydrogen peroxide

  13. Comparison of Hydrogen Peroxide Contact Lens Disinfection Systems and Solutions against Acanthamoeba polyphaga

    Science.gov (United States)

    Hughes, Reanne; Kilvington, Simon

    2001-01-01

    Acanthamoeba is a free-living amoeba causing a potentially blinding infection of the cornea. Contact lens wearers are most at risk and account for some 95% of cases. Hydrogen peroxide is used for contact lens disinfection due to its broad antimicrobial activity. Lenses must be neutralized before use to avoid pronounced stinging and possible corneal damage. Neutralization is achieved by adding a catalyst during the disinfection process (one-step) or afterwards (two-step). Here, the activities of commercial peroxide systems and individual solutions against trophozoites and cysts of Acanthamoeba polyphaga were compared. All disinfection systems were active against trophozoites, giving a ≥3-log (99.9%) kill within 1 h. Of the four one-step systems, only one showed some cysticidal activity, giving a 1.28 ± 0.41-log reduction. Both two-step systems were cysticidal, giving a ≥3-log kill at 4 h. All system peroxide solutions were cysticidal, giving a ≥3-log kill by 4 to 6 h. Variation in the cysticidal rate was observed with two solutions that gave a 1.8- to 2.1-log kill at 4 h compared with 3.0 to 4.0 for the rest (P sodium perborate or the contact lens protein remover subtilisin A. Two-step systems are cysticidal providing contact times of at least 4 h are employed. Variation in cyst killing occurs between peroxide solutions, possibly due to formulation differences. One-step systems are less effective against Acanthamoeba cysts due to rapid peroxide neutralization. The cysticidal activity of one-step systems could be improved if neutralization rates were retarded. PMID:11408220

  14. Tooth bleaching by different concentrations of carbamide peroxide and hydrogen peroxide whitening strips: an in vitro study.

    Science.gov (United States)

    Sulieman, Munther; MacDonald, Emma; Rees, Jeremy S; Newcombe, Robert G; Addy, Martin

    2006-01-01

    To investigate the tooth whitening effects of various concentrations of carbamide peroxide (CP) gels and 6% hydrogen peroxide (HP) whitening strips used on an intrinsic, in vitro stain model in a simulated home-applied bleaching protocol. Extracted third molars were sectioned and stained to Vita shade C4 using a standardized tea solution. Stained specimens were then bleached with 10, 15, 20, 22, and 30% CP gels applied in custom-made trays for 8-hour sessions for 14 days. A 6% HP whitening strip product was also tested in a regimen of twice-daily 30-minute treatments for 14 days. Shades were assessed at baseline and at 2, 5, 7, 10, and 14 days of treatment using a shade guide (SG) and a shade vision system (SVS), recorded as shade guide unit (SGU) changes from baseline, and CIE L*a*b* recordings using a chromometer. By day 14, all CP treatments resulted in at least 12 SGU improvements by SG and SVS methods: the HP treatment mean was just less than 12 SGU. With the chromometer, the CP improvements ranged from approximately 19 to 28 units and 16 units for the HP whitening strips. Observationally, by SG and SVS, CP treatments achieved the maximum improvement (12-13 SGU) at different time points: day 5 for 30% CP, day 10 for 22% CP, and day 14 for the other three treatments. SG and SVS data were virtually binary, switching from 0 to scores of 9 or above as bleaching progressed. The differences between the six treatments in the mean day to achieve a positive SG or SVS score (9 or more units) approached significance. For each of the SG, SVS, and L*a*b* scores, the dose-response correlation with CP concentration was significant at one or more assessment times. SG and SVS showed extremely strong agreement in detecting change and substantial agreement with L*a*b*. This in vitro study supports the limited data available from the very few available randomized controlled clinical trials indicating that CP and HP home-use bleaching systems can achieve considerable tooth

  15. Clinical evaluation of a novel whitening gel, containing 6% hydrogen peroxide and a standard fluoride toothpaste.

    Science.gov (United States)

    Collins, Luisa Zoe; Maggio, Brenda; Liebman, Joanne; Blanck, Maria; Lefort, Stephane; Waterfield, Philip; Littlewood, David; Naeeni, Mojgan; Schäfer, Friedrich

    2004-01-01

    The aim of this study was to determine the effect on tooth colour (after 1 and 2 weeks use) of a self-applied tooth-whitening gel containing 6% hydrogen peroxide using a novel applicator, compared to a standard fluoride toothpaste. A 2-week, examiner-blind, stratified, parallel design clinical trial was conducted. Efficacy was measured by comparing the Vita shade scores recorded at baseline and after 1 and 2 weeks of product application. To qualify for the study, subjects were required to have at least one upper incisor/canine tooth measuring Vita shade A3 or darker. All upper incisors/canines of qualifying subjects were evaluated for change in Vita shade irrespective of their level of whiteness at baseline, allowing for the whitening gel to be tested on the full range of Vita tooth shades. One hundred and seventeen subjects were divided into two groups, balanced according to their darkest tooth shade. One group followed a 2-week, twice-daily regimen of brushing with toothpaste followed by the application of the hydrogen peroxide whitening gel. The other group brushed twice daily with toothpaste for 2 weeks. Subjects using the whitening gel showed a statistically significant improvement, (ptoothpaste only group (0.14 and 0.35 units change after 1 and 2 weeks). The self-applied tooth-whitening gel containing 6% hydrogen peroxide has been shown to significantly improve the whiteness of teeth after 1 and 2 weeks of product use, compared to the baseline and the toothpaste only group.

  16. Induction of eosinophil apoptosis by hydrogen peroxide promotes the resolution of allergic inflammation

    Science.gov (United States)

    Reis, A C; Alessandri, A L; Athayde, R M; Perez, D A; Vago, J P; Ávila, T V; Ferreira, T P T; de Arantes, A CS; de Sá Coutinho, D; Rachid, M A; Sousa, L P; Martins, M A; Menezes, G B; Rossi, A G; Teixeira, M M; Pinho, V

    2015-01-01

    Eosinophils are effector cells that have an important role in the pathogenesis of allergic disease. Defective removal of these cells likely leads to chronic inflammatory diseases such as asthma. Thus, there is great interest in understanding the mechanisms responsible for the elimination of eosinophils from inflammatory sites. Previous studies have demonstrated a role for certain mediators and molecular pathways responsible for the survival and death of leukocytes at sites of inflammation. Reactive oxygen species have been described as proinflammatory mediators but their role in the resolution phase of inflammation is poorly understood. The aim of this study was to investigate the effect of reactive oxygen species in the resolution of allergic inflammatory responses. An eosinophilic cell line (Eol-1) was treated with hydrogen peroxide and apoptosis was measured. Allergic inflammation was induced in ovalbumin sensitized and challenged mouse models and reactive oxygen species were administered at the peak of inflammatory cell infiltrate. Inflammatory cell numbers, cytokine and chemokine levels, mucus production, inflammatory cell apoptosis and peribronchiolar matrix deposition was quantified in the lungs. Resistance and elastance were measured at baseline and after aerosolized methacholine. Hydrogen peroxide accelerates resolution of airway inflammation by induction of caspase-dependent apoptosis of eosinophils and decrease remodeling, mucus deposition, inflammatory cytokine production and airway hyperreactivity. Moreover, the inhibition of reactive oxygen species production by apocynin or in gp91phox−/− mice prolonged the inflammatory response. Hydrogen peroxide induces Eol-1 apoptosis in vitro and enhances the resolution of inflammation and improves lung function in vivo by inducing caspase-dependent apoptosis of eosinophils. PMID:25675292

  17. Bromate Formation Characteristics of UV Irradiation, Hydrogen Peroxide Addition, Ozonation, and Their Combination Processes

    Directory of Open Access Journals (Sweden)

    Naoyuki Kishimoto

    2012-01-01

    Full Text Available Bromate formation characteristics of six-physicochemical oxidation processes, UV irradiation, single addition of hydrogen peroxide, ozonation, UV irradiation with hydrogen peroxide addition (UV/H2O2, ozonation with hydrogen peroxide addition (O3/H2O2, and ozonation with UV irradiation (O3/UV were investigated using 1.88 μM of potassium bromide solution with or without 6.4 μM of 4-chlorobenzoic acid. Bromate was not detected during UV irradiation, single addition of H2O2, and UV/H2O2, whereas ozone-based treatments produced . Hydroxyl radicals played more important role in bromate formation than molecular ozone. Acidification and addition of radical scavengers such as 4-chlorobenzoic acid were effective in inhibiting bromate formation during the ozone-based treatments because of inhibition of hydroxyl radical generation and consumption of hydroxyl radicals, respectively. The H2O2 addition was unable to decompose 4-chlorobenzoic acid, though O3/UV and O3/H2O2 showed the rapid degradation, and UV irradiation and UV/H2O2 showed the slow degradation. Consequently, if the concentration of organic contaminants is low, the UV irradiation and/or UV/H2O2 are applicable to organic contaminants removal without bromate formation. However, if the concentration of organic contaminants is high, O3/H2O2 and O3/UV should be discussed as advanced oxidation processes because of their high organic removal efficiency and low bromate formation potential at the optimum condition.

  18. Isothermal Microcalorimetric Evaluation of Compatibility of Proposed Injector Materials with High-Test Hydrogen Peroxide Propellant

    Science.gov (United States)

    Gostowski, Rudy

    2003-01-01

    High-test hydrogen peroxide (HTP) is receiving renewed interest as a monopropellant and as the oxidizer for bipropellant systems. HTP is hydrogen peroxide in concentrations ranging from 70 to 98%. All surfaces wetted by HTP must be evaluated for compatibility with the fluid. In the case of tanks, lines and valves compatibility is required to preserve the HTP oxygen and energy content and to avoid overpressurization due to decomposition. With injectors and regenerative cooling passages shorter exposure time reduces these concerns. However, phase changes from fluid to gas impact heat transfer and become the dominant compatibility concern. Isothermal microcalorimetry (IMC) provides a convenient and reproducible means to observe the decomposition of HTP when exposed to structural materials and therefore the compatibility of those materials'. The instrument provides heat flow values in terms of watts that may be converted to a reaction rate given the heat of reaction for the decomposition of hydrogen peroxide. These values are then converted to percent active oxygen loss per week (%AOL/wk) to preserve an earlier convention for quantifying HTP compatibility. Additionally, qualitative designations of compatibility have been assigned to these values. This scheme consists of four classes with Class 1 being the most compatible. While historical compatibility data is available its current applicability is in question due to subtle changes in the compositions of both HTP and structural materials. Trace levels of molecules can have significant influence on compatibility. Therefore representative samples of materials must be evaluated with current HTP formulations. In this work seven materials were selected for their strength characteristics at high temperature as expected in a HTP injector. The materials were then evaluated by IMC for HTP compatibility.

  19. Effect of Hydrogen Peroxide on Immersion Challenge of Rainbow Trout Fry with Flavobacterium psychrophilum

    DEFF Research Database (Denmark)

    Henriksen, Maya Maria Mihályi; Madsen, Lone; Dalsgaard, Inger

    2013-01-01

    and produce high levels of mortality attempts to establish a reproducible immersion model have been less successful. Various concentrations of hydrogen peroxide (H2O2) were evaluated before being used as a pre-treatment stressor prior to immersion exposure to F. psychrophilum. H2O2 accelerated the onset...... of mortality and increased mortality approximately two-fold; from 9.1% to 19.2% and from 14.7% to 30.3% in two separate experiments. Clinical signs observed in the infected fish corresponded to symptoms characteristically seen during natural outbreaks. These findings indicate that pre-treatment with H2O2 can...

  20. 8-Alkylcoumarins from the Fruits of Cnidium monnieri Protect against Hydrogen Peroxide Induced Oxidative Stress Damage

    Directory of Open Access Journals (Sweden)

    Chi-I Chang

    2014-03-01

    Full Text Available Three new 8-alkylcoumarins, 7-O-methylphellodenol-B (1, 7-methoxy-8-(3-methyl- 2,3-epoxy-1-oxobutylchromen-2-one (2, and 3'-O-methylvaginol (3, together with seven known compounds (4–10 were isolated from the fruits of Cnidium monnieri. Their structures were determined by detailed analysis of spectroscopic data and comparison with the data of known analogues. All the isolates were evaluated the cytoprotective activity by MTS cell proliferation assay and the results showed that all the three new 8-alkylcoumarins exhibited cytoprotective effect on Neuro-2a neuroblastoma cells injured by hydrogen peroxide.

  1. 8-Alkylcoumarins from the fruits of Cnidium monnieri protect against hydrogen peroxide induced oxidative stress damage.

    Science.gov (United States)

    Chang, Chi-I; Hu, Wan-Chiao; Shen, Che-Piao; Hsu, Ban-Dar; Lin, Wei-Yong; Sung, Ping-Jyun; Wang, Wei-Hsien; Wu, Jin-Bin; Kuo, Yueh-Hsiung

    2014-03-17

    Three new 8-alkylcoumarins, 7-O-methylphellodenol-B (1), 7-methoxy-8-(3-methyl- 2,3-epoxy-1-oxobutyl)chromen-2-one (2), and 3'-O-methylvaginol (3), together with seven known compounds (4-10) were isolated from the fruits of Cnidium monnieri. Their structures were determined by detailed analysis of spectroscopic data and comparison with the data of known analogues. All the isolates were evaluated the cytoprotective activity by MTS cell proliferation assay and the results showed that all the three new 8-alkylcoumarins exhibited cytoprotective effect on Neuro-2a neuroblastoma cells injured by hydrogen peroxide.

  2. Low-dose hydrogen peroxide application in closed recirculating aquaculture systems

    DEFF Research Database (Denmark)

    Pedersen, Lars-Flemming; Good, C.; Pedersen, Per Bovbjerg

    2012-01-01

    The aim of the present work was to simulate water treatment practices with hydrogen peroxide (HP) in recirculating aquaculture systems (RAS). Six identical 1,700-L pilot-scale RAS were divided into two experimental groups based on daily feed allocation and operated under constant conditions...... and contradict prevailing notions that HP cannot be used safely in RAS that employ biofiltration. The development of effective new HP treatment protocols for recirculating aquaculture could reduce the current dependence on formalin to improve water quality and control parasitic loads...

  3. Development of a rechargeable optical hydrogen peroxide sensor - sensor design and biological application

    DEFF Research Database (Denmark)

    Koren, Klaus; Jensen, Peter Østrup; Kühl, Michael

    2016-01-01

    Hydrogen peroxide (H2O2) is an important member of the reactive oxygen species (ROS) family. Among ROS, H2O2 is considered the most long-lived and can accumulate inside and outside of cells, where it is involved in both vital (signaling) and deadly (toxic) reactions depending on its concentration....... Quantifying H2O2 within biological samples is challenging and often not possible. Here we present a quasi-reversible fiber-optic sensor capable of measuring H2O2 concentrations ranging from 1-100 μM within different biological samples. Based on a Prussian blue/white redox cycle and a simple sensor recharging...

  4. A Self-Supported Direct Borohydride-Hydrogen Peroxide Fuel Cell System

    Directory of Open Access Journals (Sweden)

    Ashok K. Shukla

    2009-04-01

    Full Text Available A self-supported direct borohydride-hydrogen peroxide fuel cell system with internal manifolds and an auxiliary control unit is reported. The system, while operating under ambient conditions, delivers a peak power of 40 W with about 2 W to run the auxiliary control unit. A critical cause and effect analysis, on the data for single cells and stack, suggests the optimum concentrations of fuel and oxidant to be 8 wt. % NaBH4 and 2 M H2O2, respectively in extending the operating time of the system. Such a fuel cell system is ideally suited for submersible and aerospace applications where anaerobic conditions prevail.

  5. Inactivation of possible microorganism food contaminants on packaging foils using nonthermal plasma and hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Scholtz, V., E-mail: Vladimir.Scholtz@vscht.cz; Khun, J. [Institute of Chemical Technology in Prague, Department of Physics and Measurements, Faculty of Chemical Engineering (Czech Republic); Soušková, H. [Institute of Chemical Technology in Prague, Department of Computing and Control Engineering, Faculty of Chemical Engineering (Czech Republic); Čeřovský, M. [Institute of Chemical Technology in Prague, Department of Food Preservation, Faculty of Food and Biochemical Technology (Czech Republic)

    2015-07-15

    The inactivation effect of nonthermal plasma generated in electric discharge burning in air atmosphere with water or hydrogen peroxide aerosol for the application to the microbial decontamination of packaging foils is studied. The microbial inactivation is studied on two bacterial, two yeasts, and two filamentous micromycete species. The inactivation of all contaminating microorganisms becomes on the area of full 8.5 cm in diameter circular sample after short times of several tens of seconds. Described apparatus may present a possible alternative method of microbial decontamination of food packaging material or other thermolabile materials.

  6. Salinity-Gradient Energy Driven Microbial Electrosynthesis of Hydrogen Peroxide from Oxygen Reduction

    DEFF Research Database (Denmark)

    Li, Xiaohu; Zhang, Yifeng; Angelidaki, Irini

    2015-01-01

    Hydrogen peroxide (H2O2) is widely used in various chemical industries and environmental remediation. Recently, bioelectrochemical systems (BES) have gained increasing attention for synthesizing H2O2 with simultaneous wastewater treatment[1]. However, in order to get high-yield H2O2 requires...... additional electrical energy to power these BES or control the cathode potential. In this study, we develop an innovative BES called microbial reverse-electrodialysis electrolysis cell (MREC) to produce H2O2 in cathode. In the MREC(See Fig.1), the salinity-gradient energy between seawater and river water can...

  7. Urea–hydrogen peroxide prompted the selective and controlled oxidation of thioglycosides into sulfoxides and sulfones

    Directory of Open Access Journals (Sweden)

    Adesh Kumar Singh

    2017-06-01

    Full Text Available A practical method for the selective and controlled oxidation of thioglycosides to corresponding glycosyl sulfoxides and sulfones is reported using urea–hydrogen peroxide (UHP. A wide range of glycosyl sulfoxides are selectively achieved using 1.5 equiv of UHP at 60 °C while corresponding sulfones are achieved using 2.5 equiv of UHP at 80 °C in acetic acid. Remarkably, oxidation susceptible olefin functional groups were found to be stable during the oxidation of sulfide.

  8. A Possible Biogenic Origin for Hydrogen Peroxide on Mars: The Viking Results Reinterpreted

    OpenAIRE

    Houtkooper, Joop M.; Schulze-Makuch, Dirk

    2006-01-01

    The adaptability of extremophiles on Earth raises the question of what strategies putative life might have used to adapt to the present conditions on Mars. Here, we hypothesize that organisms might utilize a water-hydrogen peroxide (H2O-H2O2) mixture rather than water as an intracellular liquid. This adaptation would have the particular advantages in the martian environment of providing a low freezing point, a source of oxygen, and hygroscopicity. The findings by the Viking experiments are re...

  9. Involvement of polyamine oxidase-produced hydrogen peroxide during coleorhiza-limited germination of rice seeds

    Directory of Open Access Journals (Sweden)

    Bing Xian Chen

    2016-08-01

    Full Text Available Seed germination is a complicated biological process that requires regulated enzymatic and non-enzymatic reactions. The action of polyamine oxidase (PAO produces hydrogen peroxide (H2O2, which promotes dicot seed germination. However, whether and, if so, how PAOs regulate monocot seed germination via H2O2 production is unclear. Herein, we report that the coleorhiza is the main physical barrier to radicle protrusion during germination of rice seed (a monocot seed and that it does so in a manner similar to that of dicot seed micropylar endosperm. We found that H2O2 specifically and steadily accumulated in the coleorhizae and radicles of germinating rice seeds and was accompanied by increased PAO activity as the germination percentage increased. These physiological indexes were strongly decreased in number by guazatine, a PAO inhibitor. We also identified 11 PAO homologs (OsPAO1–11 in the rice genome, which could be classified into four subfamilies (I, IIa, IIb, and III. The OsPAO genes in subfamilies I, IIa, and IIb (OsPAO1–7 encode PAOs, whereas those in subfamily III (OsPAO8–11 encode histone lysine-specific demethylases. In silico–characterized expression profiles of OsPAO1–7 and those determined by qPCR revealed that OsPAO5 is markedly upregulated in imbibed seeds compared with dry seeds and that its transcript accumulated to a higher level in embryos than in the endosperm. Moreover, its transcriptional abundance increased gradually during seed germination in water and was inhibited by 5 mM guazatine. Taken together, these results suggest that PAO-generated H2O2 is involved in coleorhiza-limited rice seed germination and that OsPAO5 expression accounts for most PAO expression and activity during rice seed germination. These findings should facilitate further study of PAOs and provide valuable information for functional validation of these proteins during seed germination of monocot cereals.

  10. Ozone and hydrogen peroxide during summer smog episodes over the Swiss Plateau: Measurements and model simulations

    Science.gov (United States)

    Dommen, Josef; Neftel, Albrecht; Sigg, Andreas; Jacob, Daniel J.

    1995-05-01

    As part of the POLLUMET (Pollution and Meteorology in Switzerland) study, measurements of O3, NO2, and H2O2 were made at ground stations, by aircraft, and manned hydrogen balloons to characterize the photochemical processes prevailing during times of high ozone production. During summer smog episodes, elevated ozone concentrations were found over the whole area of the Swiss Plateau, which is a densely populated and industrialized region. However, NO2 concentrations were generally at a low level in the afternoon. An increase of hydrogen peroxide concentration in the mixing layer during photochemical episodes was observed. To understand better the photochemical processes which control ozone formation over the Swiss Plateau, calculations with the Harvard photochemical model and the Harwell photochemical trajectory model were conducted. A comparison of model results with measurements of the triad O3, NO2, and H2O2 indicates an ozone formation under low NOx conditions.

  11. Treatment of portal venous gas embolism with hyperbaric oxygen after accidental ingestion of hydrogen peroxide: a case report and review of the literature.

    Science.gov (United States)

    Papafragkou, Sotirios; Gasparyan, Anna; Batista, Richard; Scott, Paul

    2012-07-01

    It is well known that hydrogen peroxide ingestion can cause gas embolism. To report a case illustrating that the definitive, most effective treatment for gas embolism is hyperbaric oxygen therapy. We present a case of a woman who presented to the Emergency Department with acute abdominal pain after an accidental ingestion of concentrated hydrogen peroxide. Complete recovery from her symptoms occurred quickly with hyperbaric oxygen therapy. This is a case report of the successful use of hyperbaric oxygen therapy to treat portal venous gas embolism caused by hydrogen peroxide ingestion. Hyperbaric oxygen therapy can be considered for the treatment of symptomatic hydrogen peroxide ingestion. Copyright © 2012 Elsevier Inc. All rights reserved.

  12. Synthesis of surface roughed Pt nanowires and their application as electrochemical sensors for hydrogen peroxide detection.

    Science.gov (United States)

    Gao, Fan; Li, Zhiyang; Ruan, Dajiang; Gu, Zhiyong

    2014-09-01

    In this paper, platinum nanowires with roughed surface textures were fabricated by a galvanostatic electrodeposition method for electrochemical sensors toward hydrogen peroxide detection. The electrochemical behavior of the glassy carbon electrode modified with these nanowires has been studied for oxidation of hydrogen peroxide by using cyclic voltammetry and amperometry in phosphate buffer solution. Surface roughness was found to enhance the sensitivity of the Pt nanowire based electrochemical sensor towards H2O2. The Pt nanowires with rough surfaces displayed higher electrocatalytic response compared to nanowires with smooth surfaces, with a sensitivity of 171 μA mM(-1) cm(-2), and linear dynamic range up to 35 mM. The nanowire concentration effect on the sensing behavior was investigated with the best sensitivity output found at a nanowire concentration of roughly 8.6 x 10(7) number of nanowires/cm2. The new sensor also showed good anti-interference property and exhibited high accuracy when a real water sample containing H2O2 was measured.

  13. Inhaled nitric oxide prevents the increase in pulmonary vascular permeability caused by hydrogen peroxide.

    Science.gov (United States)

    Poss, W B; Timmons, O D; Farrukh, I S; Hoidal, J R; Michael, J R

    1995-09-01

    Given the interest in using inhaled nitric oxide (NO.) to treat acute lung injury and the importance of oxygen radicals in its pathogenesis, we studied the effects, in buffer-perfused isolated rabbit lungs, of inhaled NO. (24 ppm) on the injury caused by generating hydrogen peroxide with glucose and glucose oxidase (GOX). Experiments were performed at a constant pulmonary arterial pressure. GOX substantially augmented vascular permeability, as demonstrated by an increase in the lung-to-perfusate 125I-labeled albumin ratio, lavage-to-perfusate 125I-albumin ratio, wet-to-dry lung weight ratio, and pulmonary vascular filtration coefficient. Lungs treated with inhaled NO. before perfusion with GOX had lung-to-perfusate and lavage-to-perfusate 125I-albumin ratios that were not significantly different from control values and intermediate between the control and GOX groups. Inhaled NO. also prevented the increase in wet-to-dry lung weight ratio and pulmonary vascular filtration coefficient caused by GOX.. Thus inhaled NO. substantially reduced in the isolated lung the increase in pulmonary vascular permeability produced by the intravascular generation of hydrogen peroxide.

  14. Nitrogen-Rich Polyacrylonitrile-Based Graphitic Carbons for Hydrogen Peroxide Sensing

    Directory of Open Access Journals (Sweden)

    Brandon Pollack

    2017-10-01

    Full Text Available Catalytic substrate, which is devoid of expensive noble metals and enzymes for hydrogen peroxide (H2O2, reduction reactions can be obtained via nitrogen doping of graphite. Here, we report a facile fabrication method for obtaining such nitrogen doped graphitized carbon using polyacrylonitrile (PAN mats and its use in H2O2 sensing. A high degree of graphitization was obtained with a mechanical treatment of the PAN fibers embedded with carbon nanotubes (CNT prior to the pyrolysis step. The electrochemical testing showed a limit of detection (LOD 0.609 µM and sensitivity of 2.54 µA cm−2 mM−1. The promising sensing performance of the developed carbon electrodes can be attributed to the presence of high content of pyridinic and graphitic nitrogens in the pyrolytic carbons, as confirmed by X-ray photoelectron spectroscopy. The reported results suggest that, despite their simple fabrication, the hydrogen peroxide sensors developed from pyrolytic carbon nanofibers are comparable with their sophisticated nitrogen-doped graphene counterparts.

  15. Synthesis and radiosensitization properties of hydrogen peroxide and sodium hyaluronate complex

    Energy Technology Data Exchange (ETDEWEB)

    Rosli, Nur Ratasha Alia Md.; Mohamed, Faizal; Heng, Cheong Kai; Rahman, Irman Abdul; Ahmad, Ainee Fatimah; Mohamad, Hur Munawar Kabir [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi, Selangor (Malaysia)

    2014-09-03

    Cancer cells which are large in size are resistant towards radiation therapy due to the presence of large amount of anti-oxidative enzymes and hypoxic cancer cells. Thus radiosensitizer agents have been developed to enhance the therapeutic effect of radiotherapy by increasing the sensitivity of these cancer cells towards radiation. This study is conducted to investigate the radiosensitization properties of radiosensitizer complex containing hydrogen peroxide and sodium hyaluronate. Combination with sodium hyaluronate may decrease reactivity of hydrogen peroxide but maintain the oxygen concentration needed for radiosensitizing effect. HepG2 cancer cells are cultured as the mean of test subject. Cancer cell samples which are targeted and not targeted with these radiosensitizers are irradiated with 2Gy single fractionated dose. Results obtained shows that the cancer cells which are not targeted with radiosensitizers has a cell viability of 98.80±0.37% after a time interval of 48 hours and has even repopulated over 100% after a 72 hour time interval. This shows that the cancer cells are resistant towards radiation. However, when the cancer cells are targeted with radiosensitizers prior to irradiation, there is a reduction of cell viability by 25.50±10.81% and 10.30±5.10% at time intervals of 48 and 72 hours respectively. This indicates that through the use of these radiosensitizers, cancer cells are more sensitive towards radiation.

  16. Synthesis and radiosensitization properties of hydrogen peroxide and sodium hyaluronate complex

    Science.gov (United States)

    Rosli, Nur Ratasha Alia Md.; Mohamed, Faizal; Heng, Cheong Kai; Rahman, Irman Abdul; Ahmad, Ainee Fatimah; Mohamad, Hur Munawar Kabir

    2014-09-01

    Cancer cells which are large in size are resistant towards radiation therapy due to the presence of large amount of anti-oxidative enzymes and hypoxic cancer cells. Thus radiosensitizer agents have been developed to enhance the therapeutic effect of radiotherapy by increasing the sensitivity of these cancer cells towards radiation. This study is conducted to investigate the radiosensitization properties of radiosensitizer complex containing hydrogen peroxide and sodium hyaluronate. Combination with sodium hyaluronate may decrease reactivity of hydrogen peroxide but maintain the oxygen concentration needed for radiosensitizing effect. HepG2 cancer cells are cultured as the mean of test subject. Cancer cell samples which are targeted and not targeted with these radiosensitizers are irradiated with 2Gy single fractionated dose. Results obtained shows that the cancer cells which are not targeted with radiosensitizers has a cell viability of 98.80±0.37% after a time interval of 48 hours and has even repopulated over 100% after a 72 hour time interval. This shows that the cancer cells are resistant towards radiation. However, when the cancer cells are targeted with radiosensitizers prior to irradiation, there is a reduction of cell viability by 25.50±10.81% and 10.30±5.10% at time intervals of 48 and 72 hours respectively. This indicates that through the use of these radiosensitizers, cancer cells are more sensitive towards radiation.

  17. The Effect of Porcelain Firing on Electrochemical Behavior of a Dental Alloy in Hydrogen Peroxide.

    Science.gov (United States)

    Tamam, Evşen; Aydın, A Kevser; Bilgiç, Semra

    2015-07-01

    The aim of this study was to evaluate changes in electrochemical corrosion properties of porcelain firing simulated nickel-chromium dental casting alloy exposed to a 10% hydrogen peroxide bleaching agent. The electrochemical corrosion behavior of a Ni-Cr alloy was evaluated by cyclic polarization test in the aerated electrolyte (pH = 6.5). Test groups were produced in as-cast (group 1, control group) and simulated porcelain firing (group 2: heat-treated/mean value; group 3: heat-treated/cycle) conditions. Scanning electron microscopy (SEM) was also used to examine the alloy surfaces before and after the corrosion test. The ranking of the groups with respect to Ecorr and Icorr was as follows: 1, 2, 3 and 3, 1, 2, respectively. Group 3 exhibited the greatest and group 2 displayed the least corrosion tendencies. An increase in corrosion rates was observed after heat treatment/cycle state. Post-corrosion SEM photographs were also consistent with the test results. Within the parameters of this study, a single heat treatment is insufficient to cause upheaval in corrosion behavior of a Ni-Cr alloy subjected to 10% hydrogen peroxide. © 2014 by the American College of Prosthodontists.

  18. Influence of Catalase Activity on Resistance of Coagulase-positive Staphylococci to Hydrogen Peroxide1

    Science.gov (United States)

    Amin, V. M.; Olson, N. F.

    1968-01-01

    Catalase activities of intact cells and cell-free extracts of coagulase-positive staphylococcal cultures 105B and 558D isolated from milk, culture 25042 from a clinical source, and Staphylococcus aureus 196E were determined at 32.2 C. Cultures were treated with 0.025 and 0.05% hydrogen peroxide at 37.8 and 54.4 C and without hydrogen peroxide at 54.4 C to determine the relationship between catalase activity and resistance to these treatments. The relationship held true for cultures 105B and 196E; culture 105B had the lowest catalase activity and lowest resistance to H2O2 at 37.8 C, whereas S. aureus 196E possessed a high catalase activity and was most resistant at 37.8 C. Catalase activities of cell-free extracts of cultures 25042, 558, and 196E were similar, but resistance to H2O2 at 37.8 C was greater for culture 196E. The lower resistance of culture 25042 was related to low catalase activities of whole cells of this culture, which were only one-third that of whole cells of culture 196E. Culture 558 was least resistant to heat treatment at 54.4 C and showed the greatest sensitivity to added H2O2 at this temperature. PMID:5645413

  19. Investigation of Influential Parameters in Deep Oxidative Desulfurization of Dibenzothiophene with Hydrogen Peroxide and Formic Acid

    Directory of Open Access Journals (Sweden)

    Alireza Haghighat Mamaghani

    2013-01-01

    Full Text Available An effective oxidative system consisting of hydrogen peroxide, formic acid, and sulfuric acid followed by an extractive stage were implemented to remove dibenzothiophene in the simulated fuel oil. The results revealed such a great performance in the case of H2O2 in the presence of formic and sulfuric acids that led to the removal of sulfur compounds. Sulfuric acid was employed to increase the acidity of media as well as catalytic activity together with formic acid. The oxidation reaction was followed by a liquid-liquid extraction stage using acetonitrile as a polar solvent to remove produced sulfones from the model fuel. The impact of operating parameters including the molar ratio of formic acid to sulfur (, hydrogen peroxide to sulfur (, and the time of reaction was investigated using Box-Behnken experimental design for oxidation of the model fuel. A significant quadratic model was introduced for the sulfur removal as a function of effective parameters by the statistic analysis.

  20. Antimicrobial mechanisms behind photodynamic effect in the presence of hydrogen peroxide.

    Science.gov (United States)

    Garcez, Aguinaldo Silva; Núñez, Silvia Cristina; Baptista, Mauricio S; Daghastanli, Nasser Ali; Itri, Rosangela; Hamblin, Michael R; Ribeiro, Martha Simões

    2011-04-01

    This study describes the use of methylene blue (MB) plus light (photodynamic inactivation, PDI) in the presence of hydrogen peroxide (H(2)O(2)) to kill Staphylococcus aureus, Escherichia coli, and Candida albicans. When H(2)O(2) was added to MB plus light there was an increased antimicrobial effect, which could be due to a change in the type of ROS generated or increased microbial uptake of MB. To clarify the mechanism, the production of ROS was investigated in the presence and absence of H(2)O(2). It was observed that ROS production was almost inhibited by the presence of H(2)O(2) when cells were not present. In addition, experiments using different sequence combinations of MB and H(2)O(2) were performed and MB optical properties inside the cell were analyzed. Spectroscopy experiments suggested that the amount of MB was higher inside the cells when H(2)O(2) was used before or simultaneously with PDI, and ROS formation inside C. albicans cells confirmed that ROS production is higher in the presence of H(2)O(2). Moreover enzymatic reduction of MB by E. coli during photosensitizer uptake to the photochemically inactive leucoMB could be reversed by the oxidative effects of hydrogen peroxide, increasing ROS formation inside the microorganism. Therefore, the combination of a photosensitizer such as MB and H(2)O(2) is an interesting approach to improve PDI efficiency.

  1. Study of the hydrogen peroxide bleaching agent effects on bovine enamel using X-ray fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Ruda F.; Calazans, Fernanda S.; Miranda, Mauro S.; Santos, Ramon S.; Anjos, Marcelino J.; Assis, Joaquim T. [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    Hydrogen Peroxide's a bleaching agent capable of oxidizing a wide range of colored organic, causing discoloration and hence bleaching of the substrate, but some authors related the occurrence of side effects related to bleaching of the tooth structure, such as changes in morphology superficial. It was used 6 bovine incisors, each tooth was initially evaluated six times in different areas to obtain the count of elements phosphorus and calcium using X-Ray Fluorescence. The teeth were randomly divided in two groups: both groups were submitted to bleaching in office with hydrogen peroxide 38%, once a week during three weeks. Group 1 was stored in distilled water and group 2 in artificial saliva, between the sessions. The measurements were repeated every seven days before the bleaching treatment. Besides that, changes in mineral levels were always assessed in the same area and using the same procedure. It was observed that the bleaching was not able to demineralize the tooth enamel studied. (author)

  2. Simultaneous high-resolution measurement of mitochondrial respiration and hydrogen peroxide production.

    Science.gov (United States)

    Krumschnabel, Gerhard; Fontana-Ayoub, Mona; Sumbalova, Zuzana; Heidler, Juliana; Gauper, Kathrin; Fasching, Mario; Gnaiger, Erich

    2015-01-01

    Mitochondrial respiration is associated with the formation of reactive oxygen species, primarily in the form of superoxide (O2 (•-)) and particularly hydrogen peroxide (H2O2). Since H2O2 plays important roles in physiology and pathology, measurement of hydrogen peroxide has received considerable attention over many years. Here we describe how the well-established Amplex Red assay can be used to detect H2O2 production in combination with the simultaneous assessment of mitochondrial bioenergetics by high-resolution respirometry. Fundamental instrumental and methodological parameters were optimized for analysis of the effects of various substrate, uncoupler, and inhibitor titrations (SUIT) on respiration versus H2O2 production. The sensitivity of the H2O2 assay was strongly influenced by compounds contained in different mitochondrial respiration media, which also exerted significant effects on chemical background fluorescence changes. Near linearity of the fluorescence signal was restricted to narrow ranges of accumulating resorufin concentrations independent of the nature of mitochondrial respiration media. Finally, we show an application example using isolated mouse brain mitochondria as an experimental model for the simultaneous measurement of mitochondrial respiration and H2O2 production in SUIT protocols.

  3. Cyanobacterial and microcystins dynamics following the application of hydrogen peroxide to waste stabilisation ponds

    Directory of Open Access Journals (Sweden)

    D. J. Barrington

    2013-06-01

    Full Text Available Cyanobacteria and cyanotoxins are a risk to human and ecological health, and a hindrance to biological wastewater treatment. This study investigated the use of hydrogen peroxide (H2O2 for the removal of cyanobacteria and cyanotoxins from within waste stabilization ponds (WSPs. The daily dynamics of cyanobacteria and microcystins (commonly occurring cyanotoxins were examined following the addition of H2O2 to wastewater within both the laboratory and at the full scale within a maturation WSP, the final pond in a wastewater treatment plant. Hydrogen peroxide treatment at concentrations ≥ 0.1 mg H2O2 μg−1 total phytoplankton chlorophyll a led to the lysis of cyanobacteria, in turn releasing intracellular microcystins to the dissolved state. In the full-scale trial, dissolved microcystins were then degraded to negligible concentrations by H2O2 and environmental processes within five days. A shift in the phytoplankton assemblage towards beneficial Chlorophyta species was also observed within days of H2O2 addition. However, within weeks, the Chlorophyta population was significantly reduced by the re-establishment of toxic cyanobacterial species. This re-establishment was likely due to the inflow of cyanobacteria from ponds earlier in the treatment train, suggesting that whilst H2O2 may be a suitable short-term management technique, it must be coupled with control over inflows if it is to improve WSP performance in the longer term.

  4. Template electrodeposition of high-performance copper oxide nanosensors for electrochemical analysis of hydrogen peroxide.

    Science.gov (United States)

    Rajendra Kumar Reddy, Gajjala; Kumar, P Suresh

    2017-06-01

    We report on the facile electrodeposition of copper nanostructures on graphite lead substrate using anionic, cationic and non-ionic surfactant templates. Physical and electrochemical characterisation confirmed the influence of templates on the morphology and electrochemical catalytic activities of the copper electrodeposits. These electrodes were shown to be excellent electrocatalyst for the fast detection of hydrogen peroxide. A maximum sensitivity of 951.45μA/mM/cm2, LOD of 0.43μM, response time of <1s and a linearity in wide range of concentration from 1μM to 5mM were observed when sodium dodecyl sulfate was used as the template. While most of the previously reported sensors have advantages either on the facile synthesis or fast detection of analyte, our methodology enables preparation of the electrode within 120s and analysis within another 60s without any complicated procedure, thereby demonstrating one of the fastest and cost-effective method for hydrogen peroxide analysis with high sensitivity and selectivity. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. The laboratory and clinical safety evaluation of a dentifrice containing hydrogen peroxide and baking soda.

    Science.gov (United States)

    Fischman, S L; Truelove, R B; Hart, R; Cancro, L P

    1992-01-01

    This study reports the laboratory, clinical, and microbiological finding of the safety testing and daily use of a dentifrice delivering 0.75% hydrogen peroxide and 5% baking soda. Laboratory studies using Ca45 labeled teeth and biologically stained teeth confirmed that the dentifrice did not decalcify enamel or bleach teeth. Over the course of a six-month period, 62 subjects using a hydrogen peroxide-baking soda dentifrice and 21 subjects using a control dentifrice were examined for oral soft tissue change and hard tissue alterations. No soft tissue changes attributable to the use of either dentifrice were noted. Experienced clinicians using Trubyte shade guide teeth observed no significant changes to the subjects' anterior teeth following 6 months use of the test dentifrice. Paired discrimination tests revealed that the examiners could distinguish color differences in the shade guide teeth at 0.7%. Microbiological monitoring of the subjects for six months use of their assigned dentifrice and for the following months on the control dentifrice, revealed neither an increased incidence of candida nor increased candida counts.

  6. Characterization of hydrogen peroxide-resistant Acinetobacter species isolated during the Mars Phoenix spacecraft assembly.

    Science.gov (United States)

    Derecho, I; McCoy, K B; Vaishampayan, P; Venkateswaran, K; Mogul, R

    2014-10-01

    The microbiological inventory of spacecraft and the associated assembly facility surfaces represent the primary pool of forward contaminants that may impact the integrity of life-detection missions. Herein, we report on the characterization of several strains of hydrogen peroxide-resistant Acinetobacter, which were isolated during the Mars Phoenix lander assembly. All Phoenix-associated Acinetobacter strains possessed very high catalase specific activities, and the specific strain, A. gyllenbergii 2P01AA, displayed a survival against hydrogen peroxide (no loss in 100 mM H2O2 for 1 h) that is perhaps the highest known among Gram-negative and non-spore-forming bacteria. Proteomic characterizations reveal a survival mechanism inclusive of proteins coupled to peroxide degradation (catalase and alkyl hydroperoxide reductase), energy/redox management (dihydrolipoamide dehydrogenase), protein synthesis/folding (EF-G, EF-Ts, peptidyl-tRNA hydrolase, DnaK), membrane functions (OmpA-like protein and ABC transporter-related protein), and nucleotide metabolism (HIT family hydrolase). Together, these survivability and biochemical parameters support the hypothesis that oxidative tolerance and the related biochemical features are the measurable phenotypes or outcomes for microbial survival in the spacecraft assembly facilities, where the low-humidity (desiccation) and clean (low-nutrient) conditions may serve as selective pressures. Hence, the spacecraft-associated Acinetobacter, due to the conferred oxidative tolerances, may ultimately hinder efforts to reduce spacecraft bioburden when using chemical sterilants, thus suggesting that non-spore-forming bacteria may need to be included in the bioburden accounting for future life-detection missions.

  7. The effect of hydrogen peroxide on uranium oxide films on 316L stainless steel

    Science.gov (United States)

    Wilbraham, Richard J.; Boxall, Colin; Goddard, David T.; Taylor, Robin J.; Woodbury, Simon E.

    2015-09-01

    For the first time the effect of hydrogen peroxide on the dissolution of electrodeposited uranium oxide films on 316L stainless steel planchets (acting as simulant uranium-contaminated metal surfaces) has been studied. Analysis of the H2O2-mediated film dissolution processes via open circuit potentiometry, alpha counting and SEM/EDX imaging has shown that in near-neutral solutions of pH 6.1 and at [H2O2] ⩽ 100 μmol dm-3 the electrodeposited uranium oxide layer is freely dissolving, the associated rate of film dissolution being significantly increased over leaching of similar films in pH 6.1 peroxide-free water. At H2O2 concentrations between 1 mmol dm-3 and 0.1 mol dm-3, formation of an insoluble studtite product layer occurs at the surface of the uranium oxide film. In analogy to corrosion processes on common metal substrates such as steel, the studtite layer effectively passivates the underlying uranium oxide layer against subsequent dissolution. Finally, at [H2O2] > 0.1 mol dm-3 the uranium oxide film, again in analogy to common corrosion processes, behaves as if in a transpassive state and begins to dissolve. This transition from passive to transpassive behaviour in the effect of peroxide concentration on UO2 films has not hitherto been observed or explored, either in terms of corrosion processes or otherwise. Through consideration of thermodynamic solubility product and complex formation constant data, we attribute the transition to the formation of soluble uranyl-peroxide complexes under mildly alkaline, high [H2O2] conditions - a conclusion that has implications for the design of both acid minimal, metal ion oxidant-free decontamination strategies with low secondary waste arisings, and single step processes for spent nuclear fuel dissolution such as the Carbonate-based Oxidative Leaching (COL) process.

  8. Kinetics of the decomposition and the estimation of the stability of 10% aqueous and non-aqueous hydrogen peroxide solutions

    Directory of Open Access Journals (Sweden)

    Zun Maria

    2014-12-01

    Full Text Available In this study, the stability of 10% hydrogen peroxide aqueous and non-aqueous solutions with the addition of 6% (w/w of urea was evaluated. The solutions were stored at 20°C, 30°C and 40°C, and the decomposition of hydrogen peroxide proceeded according to first-order kinetics. With the addition of the urea in the solutions, the decomposition rate constant increased and the activation energy decreased. The temperature of storage also affected the decomposition of substance, however, 10% hydrogen peroxide solutions prepared in PEG-300, and stabilized with the addition of 6% (w/w of urea had the best constancy.

  9. The Effects of Hydrogen Peroxide Solution and Tetracycline Ointment in Healing of Traumatic Facial Wounds: A Comparative Study

    Directory of Open Access Journals (Sweden)

    B. Barati

    2007-07-01

    Full Text Available Background and objectives Wound repair after a surgical operation or traumatic injuries is a coordinated process, which is highly dependent to the pre- and post-operative or traumatic care. There is no consensus on the best wound care method and application of topical therapeutic agents including diluted oxygen peroxide solution and antibiotics. This study is aimed to compare the healing effects of oxygen peroxide and tetracycline ointment in management of traumatic facial injuries. Methods 76 patients divided into two groups were entered into this randomized clinical trial. All patients sustained facial injuries requiring primary repair. The first group received 2% topical oxygen peroxide solution for 5 days, and the second group received sterile 1% tetracycline topical ointment for 5days. At the end of the fourth day, wound healing status was assessed with a chart designed for this purpose.Results No statistically significant difference was observed between the tetracycline and hydrogen peroxide groups in regards to the distance of wound margins, erythema and dehiscence. Conclusion According to our results, there is no difference in the effects of hydrogen peroxide solution or tetracycline ointment on the healing of traumatic facial wounds.Keywords: Wound Healing, Tissue Repair, Hydrogen Peroxide, Tetracycline

  10. Comparative proteomics analysis of the root apoplasts of rice seedlings in response to hydrogen peroxide.

    Directory of Open Access Journals (Sweden)

    Lu Zhou

    Full Text Available BACKGROUND: Plant apoplast is the prime site for signal perception and defense response, and of great importance in responding to environmental stresses. Hydrogen peroxide (H(2O(2 plays a pivotal role in determining the responsiveness of cells to stress. However, how the apoplast proteome changes under oxidative condition is largely unknown. In this study, we initiated a comparative proteomic analysis to explore H(2O(2-responsive proteins in the apoplast of rice seedling roots. METHODOLOGY/PRINCIPAL FINDINGS: 14-day-old rice seedlings were treated with low concentrations (300 and 600 µM of H(2O(2 for 6 h and the levels of relative electrolyte leakage, malondialdehyde and H(2O(2 were assayed in roots. The modified vacuum infiltration method was used to extract apoplast proteins of rice seedling roots, and then two-dimensional electrophoresis gel analysis revealed 58 differentially expressed protein spots under low H(2O(2 conditions. Of these, 54 were successfully identified by PMF or MS/MS as matches to 35 different proteins including known and novel H(2O(2-responsive proteins. Almost all of these identities (98% were indeed apoplast proteins confirmed either by previous experiments or through publicly available prediction programs. These proteins identified are involved in a variety of processes, including redox homeostasis, cell wall modification, signal transduction, cell defense and carbohydrate metabolism, indicating a complex regulative network in the apoplast of seedling roots under H(2O(2 stress. CONCLUSIONS/SIGNIFICANCE: The present study is the first apoplast proteome investigation of plant seedlings in response to H(2O(2 and may be of paramount importance for the understanding of the plant network to environmental stresses. Based on the abundant changes in these proteins, together with their putative functions, we proposed a possible protein network that provides new insights into oxidative stress response in the rice root apoplast

  11. Effect of algal growth phase on Aureococcus anophagefferens susceptibility to hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Randhawa, Varunpreet; Thakkar, Megha; Wei, Liping, E-mail: liping.wei@njit.edu

    2013-10-15

    Highlights: •Brown tide alga's susceptibility to H{sub 2}O{sub 2} was examined via growth and physiology responses. •The study was designed equalizing the influence of the media and cell density in test cultures. •Stationary cells was more sensitive to H{sub 2}O{sub 2} than exponential cells. •Stationary cells showed weaker non-protein thiol up-regulation than exponential cells. •Stationary cells mediated greater H{sub 2}O{sub 2} decomposition than exponential cells did. -- Abstract: A cell's growth phase could affect its susceptibility to a biocide in microbial control. This study examines the growth phase dependent susceptibility of a brown tide bloom alga Aureococcus anophagefferens to microbial biocide hydrogen peroxide (H{sub 2}O{sub 2}). Test cultures of A. anophagefferens cells in exponential and stationary growth phase and similar initial cell density (1.6 × 10{sup 6} cells mL{sup −1}) were exposed to 0.4–1.6 mg L{sup −1} H{sub 2}O{sub 2}. Changes in algal growth (in vivo fluorescence, total chlorophyll a, and cell density), cell physiology (maximum quantum yield of photosystem II, and total intracellular non-protein thiols), and H{sub 2}O{sub 2} decomposition were quantified. Results show that the stationary phase cells are more susceptible to H{sub 2}O{sub 2} than the exponential phase cells, and this is attributed to the weaker ROS (reactive oxygen species) scavenging system and consequently greater cell damage in stationary phase cells. The stationary phase cells potentially require 30–40% less H{sub 2}O{sub 2} to reach 90% removal within 12 h of treatment as compared to the exponential phase cells. The results have practical implications in brown tide bloom control with respect to the timing and the dosage of H{sub 2}O{sub 2} application.

  12. Automatic dosage of hydrogen peroxide in solar photo-Fenton plants: Development of a control strategy for efficiency enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Ortega-Gomez, E. [Department of Chemical Engineering, University of Almeria, 04120 Almeria (Spain); CIESOL, Joint Centre of the University of Almeria-CIEMAT, 04120 Almeria (Spain); Moreno Ubeda, J.C. [Department of Language and Computation, University of Almeria, 04120 Almeria (Spain); Alvarez Hervas, J.D. [Department of Language and Computation, University of Almeria, 04120 Almeria (Spain); Department of Language and Computation, University of Sevilla, 41092 Sevilla (Spain); Casas Lopez, J.L.; Santos-Juanes Jorda, L. [Department of Chemical Engineering, University of Almeria, 04120 Almeria (Spain); CIESOL, Joint Centre of the University of Almeria-CIEMAT, 04120 Almeria (Spain); Sanchez Perez, J.A., E-mail: jsanchez@ual.es [Department of Chemical Engineering, University of Almeria, 04120 Almeria (Spain); CIESOL, Joint Centre of the University of Almeria-CIEMAT, 04120 Almeria (Spain)

    2012-10-30

    Highlights: Black-Right-Pointing-Pointer Dissolved oxygen monitoring is used for automatic dosage of H{sub 2}O{sub 2} in photo-Fenton. Black-Right-Pointing-Pointer PI with anti-windup minimises H{sub 2}O{sub 2} consumption. Black-Right-Pointing-Pointer The H{sub 2}O{sub 2} consumption was reduced up to 50% with respect to manual addition strategies. Black-Right-Pointing-Pointer Appropriate H{sub 2}O{sub 2} dosage is achieved by PI with anti-windup under disturbances. - Abstract: The solar photo-Fenton process is widely used for the elimination of pollutants in aqueous effluent and, as such, is amply cited in the literature. In this process, hydrogen peroxide represents the highest operational cost. Up until now, manual dosing of H{sub 2}O{sub 2} has led to low process performance. Consequently, there is a need to automate the hydrogen peroxide dosage for use in industrial applications. As it has been demonstrated that a relationship exists between dissolved oxygen (DO) concentration and hydrogen peroxide consumption, DO can be used as a variable in optimising the hydrogen peroxide dosage. For this purpose, a model was experimentally obtained linking the dynamic behaviour of DO to hydrogen peroxide consumption. Following this, a control system was developed based on this model. This control system - a proportional and integral controller (PI) with an anti-windup mechanism - has been tested experimentally. The assays were carried out in a pilot plant under sunlight conditions and with paracetamol used as the model pollutant. In comparison with non-assisted addition methods (a sole initial or continuous addition), a decrease of 50% in hydrogen peroxide consumption was achieved when the automatic controller was used, driving an economic saving and an improvement in process efficiency.

  13. Energy Efficient Catalytic Activation of Hydrogen peroxide for Green Chemical Processes: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Terrence J.; Horwitz, Colin

    2004-11-12

    A new, highly energy efficient approach for using catalytic oxidation chemistry in multiple fields of technology has been pursued. The new catalysts, called TAML® activators, catalyze the reactions of hydrogen peroxide and other oxidants for the exceptionally rapid decontamination of noninfectious simulants (B. atrophaeus) of anthrax spores, for the energy efficient decontamination of thiophosphate pesticides, for the facile, low temperature removal of color and organochlorines from pulp and paper mill effluent, for the bleaching of dyes from textile mill effluents, and for the removal of recalcitrant dibenzothiophene compounds from diesel and gasoline fuels. Highlights include the following: 1) A 7-log kill of Bacillus atrophaeus spores has been achieved unambiguously in water under ambient conditions within 15 minutes. 2) The rapid total degradation under ambient conditions of four thiophosphate pesticides and phosphonate degradation intermediates has been achieved on treatment with TAML/peroxide, opening up potential applications of the decontamination system for phosphonate structured chemical warfare agents, for inexpensive, easy to perform degradation of stored and aged pesticide stocks (especially in Africa and Asia), for remediation of polluted sites and water bodies, and for the destruction of chemical warfare agent stockpiles. 3) A mill trial conducted in a Pennsylvanian bleached kraft pulp mill has established that TAML catalyst injected into an alkaline peroxide bleach tower can significantly lower color from the effluent stream promising a new, more cost effective, energy-saving approach for color remediation adding further evidence of the value and diverse engineering capacity of the approach to other field trials conducted on effluent streams as they exit the bleach plant. 4) Dibenzothiophenes (DBTs), including 4,6-dimethyldibenzothiophene, the most recalcitrant sulfur compounds in diesel and gasoline, can be completely removed from model gasoline

  14. Mechanism of Action of Sulforaphane as a Superoxide Radical Anion and Hydrogen Peroxide Scavenger by Double Hydrogen Transfer: A Model for Iron Superoxide Dismutase.

    Science.gov (United States)

    Prasad, Ajit Kumar; Mishra, P C

    2015-06-25

    The mechanism of action of sulforaphane as a scavenger of superoxide radical anion (O2(•-)) and hydrogen peroxide (H2O2) was investigated using density functional theory (DFT) in both gas phase and aqueous media. Iron superoxide dismutase (Fe-SOD) involved in scavenging superoxide radical anion from biological media was modeled by a complex consisting of the ferric ion (Fe(3+)) attached to three histidine rings. Reactions related to scavenging of superoxide radical anion by sulforaphane were studied using DFT in the presence and absence of Fe-SOD represented by this model in both gas phase and aqueous media. The scavenging action of sulforaphane toward both superoxide radical anion and hydrogen peroxide was found to involve the unusual mechanism of double hydrogen transfer. It was found that sulforaphane alone, without Fe-SOD, cannot scavenge superoxide radical anion in gas phase or aqueous media efficiently as the corresponding reaction barriers are very high. However, in the presence of Fe-SOD represented by the above-mentioned model, the scavenging reactions become barrierless, and so sulforaphane scavenges superoxide radical anion by converting it to hydrogen peroxide efficiently. Further, sulforaphane was found to scavenge hydrogen peroxide also very efficiently by converting it into water. Thus, the mechanism of action of sulforaphane as an excellent antioxidant has been unravelled.

  15. Acetylcholine Attenuates Hydrogen Peroxide-Induced Intracellular Calcium Dyshomeostasis Through Both Muscarinic and Nicotinic Receptors in Cardiomyocytes

    Directory of Open Access Journals (Sweden)

    Siripong Palee

    2016-06-01

    Full Text Available Background/Aims: Oxidative stress induced intracellular Ca2+ overload plays an important role in the pathophysiology of several heart diseases. Acetylcholine (ACh has been shown to suppress reactive oxygen species generation during oxidative stress. However, there is little information regarding the effects of ACh on the intracellular Ca2+ regulation in the presence of oxidative stress. Therefore, we investigated the effects of ACh applied before or after hydrogen peroxide (H2O2 treatment on the intracellular Ca2+ regulation in isolated cardiomyocytes. Methods: Single ventricular myocytes were isolated from the male Wistar rats for the intracellular Ca2+ transient study by a fluorimetric ratio technique. Results: H2O2 significantly decreased both of intracellular Ca2+ transient amplitude and decay rate. ACh applied before, but not after, H2O2 treatment attenuated the reduction of intracellular Ca2+ transient amplitude and decay rate. Both atropine (a muscarinic acetylcholine receptor blocker and mecamylamine (a nicotinic acetylcholine receptor blocker significantly decreased the protective effects of acetylcholine on the intracellular Ca2+ regulation. Moreover, the combination of atropine and mecamylamine completely abolished the protective effects of acetylcholine on intracellular Ca2+ transient amplitude and decay rate. Conclusion: ACh pretreatment attenuates H2O2-induced intracellular Ca2+ dyshomeostasis through both muscarinic and nicotinic receptors.

  16. The effect of hydrogen peroxide on uranium oxide films on 316L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Wilbraham, Richard J., E-mail: r.wilbraham@lancaster.ac.uk [The Lloyd’s Register Foundation Centre for Nuclear Engineering, Engineering Department, Lancaster University, Bailrigg, Lancashire LA1 4YR (United Kingdom); Boxall, Colin, E-mail: c.boxall@lancaster.ac.uk [The Lloyd’s Register Foundation Centre for Nuclear Engineering, Engineering Department, Lancaster University, Bailrigg, Lancashire LA1 4YR (United Kingdom); Goddard, David T., E-mail: dave.t.goddard@nnl.co.uk [National Nuclear Laboratory, Preston Laboratory, Springfields, Preston, Lancashire PR4 0XJ (United Kingdom); Taylor, Robin J., E-mail: robin.j.taylor@nnl.co.uk [National Nuclear Laboratory, Central Laboratory, Seascale, Cumbria CA20 1PG (United Kingdom); Woodbury, Simon E., E-mail: simon.woodbury@nnl.co.uk [National Nuclear Laboratory, Central Laboratory, Seascale, Cumbria CA20 1PG (United Kingdom)

    2015-09-15

    Highlights: • The first report of the presence of both UO{sub 2} and polymeric UO{sub 2}{sup 2+} in the same electrodeposited U oxide sample. • The action of H{sub 2}O{sub 2} on electrodeposited U oxides is described using corrosion based concepts. • Electrodeposited U oxide freely dissolves at hydrogen peroxide concentrations <100 μmol dm{sup −3}. • At [H{sub 2}O{sub 2}] > 0.1 mmol dm{sup −3} dissolution is inhibited by formation of a studtite passivation layer. • At [H{sub 2}O{sub 2}] ⩾ 1 mol dm{sup −3} studtite formation competes with uranyl–peroxide complex formation. - Abstract: For the first time the effect of hydrogen peroxide on the dissolution of electrodeposited uranium oxide films on 316L stainless steel planchets (acting as simulant uranium-contaminated metal surfaces) has been studied. Analysis of the H{sub 2}O{sub 2}-mediated film dissolution processes via open circuit potentiometry, alpha counting and SEM/EDX imaging has shown that in near-neutral solutions of pH 6.1 and at [H{sub 2}O{sub 2}] ⩽ 100 μmol dm{sup −3} the electrodeposited uranium oxide layer is freely dissolving, the associated rate of film dissolution being significantly increased over leaching of similar films in pH 6.1 peroxide-free water. At H{sub 2}O{sub 2} concentrations between 1 mmol dm{sup −3} and 0.1 mol dm{sup −3}, formation of an insoluble studtite product layer occurs at the surface of the uranium oxide film. In analogy to corrosion processes on common metal substrates such as steel, the studtite layer effectively passivates the underlying uranium oxide layer against subsequent dissolution. Finally, at [H{sub 2}O{sub 2}] > 0.1 mol dm{sup −3} the uranium oxide film, again in analogy to common corrosion processes, behaves as if in a transpassive state and begins to dissolve. This transition from passive to transpassive behaviour in the effect of peroxide concentration on UO{sub 2} films has not hitherto been observed or explored, either in terms

  17. Evaluation of vaporized hydrogen peroxide, Citrox and pH neutral Ecasol for decontamination of an enclosed area: a pilot study.

    LENUS (Irish Health Repository)

    Galvin, S

    2012-01-01

    Hydrogen peroxide, Ecasol and Citrox aerosols were each tested for their ability to kill a range of nosocomial pathogens. Hydrogen peroxide had the broadest microbicidal activity but operational issues limit its use. Ecasol was effective against all micro-organisms, except Clostridium difficile, while Citrox aerosols were not effective against Gram-negative bacilli.

  18. Electron paramagnetic resonance study of lipid and protein membrane components of erythrocytes oxidized with hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Mendanha, S.A.; Anjos, J.L.V.; Silva, A.H.M.; Alonso, A. [Instituto de Física, Universidade Federal de Goiás, Goiânia, GO (Brazil)

    2012-04-05

    Electron paramagnetic resonance (EPR) spectroscopy of spin labels was used to monitor membrane dynamic changes in erythrocytes subjected to oxidative stress with hydrogen peroxide (H{sub 2}O{sub 2}). The lipid spin label, 5-doxyl stearic acid, responded to dramatic reductions in membrane fluidity, which was correlated with increases in the protein content of the membrane. Membrane rigidity, associated with the binding of hemoglobin (Hb) to the erythrocyte membrane, was also indicated by a spin-labeled maleimide, 5-MSL, covalently bound to the sulfhydryl groups of membrane proteins. At 2% hematocrit, these alterations in membrane occurred at very low concentrations of H{sub 2}O{sub 2} (50 µM) after only 5 min of incubation at 37°C in azide phosphate buffer, pH 7.4. Lipid peroxidation, suggested by oxidative hemolysis and malondialdehyde formation, started at 300 µM H{sub 2}O{sub 2} (for incubation of 3 h), which is a concentration about six times higher than those detected with the probes. Ascorbic acid and α-tocopherol protected the membrane against lipoperoxidation, but did not prevent the binding of proteins to the erythrocyte membrane. Moreover, the antioxidant (+)-catechin, which also failed to prevent the cross-linking of cytoskeletal proteins with Hb, was very effective in protecting erythrocyte ghosts from lipid peroxidation induced by the Fenton reaction. This study also showed that EPR spectroscopy can be useful to assess the molecular dynamics of red blood cell membranes in both the lipid and protein domains and examine oxidation processes in a system that is so vulnerable to oxidation.

  19. Electron paramagnetic resonance study of lipid and protein membrane components of erythrocytes oxidized with hydrogen peroxide

    Directory of Open Access Journals (Sweden)

    S.A. Mendanha

    2012-06-01

    Full Text Available Electron paramagnetic resonance (EPR spectroscopy of spin labels was used to monitor membrane dynamic changes in erythrocytes subjected to oxidative stress with hydrogen peroxide (H2O2. The lipid spin label, 5-doxyl stearic acid, responded to dramatic reductions in membrane fluidity, which was correlated with increases in the protein content of the membrane. Membrane rigidity, associated with the binding of hemoglobin (Hb to the erythrocyte membrane, was also indicated by a spin-labeled maleimide, 5-MSL, covalently bound to the sulfhydryl groups of membrane proteins. At 2% hematocrit, these alterations in membrane occurred at very low concentrations of H2O2 (50 µM after only 5 min of incubation at 37°C in azide phosphate buffer, pH 7.4. Lipid peroxidation, suggested by oxidative hemolysis and malondialdehyde formation, started at 300 µM H2O2 (for incubation of 3 h, which is a concentration about six times higher than those detected with the probes. Ascorbic acid and α-tocopherol protected the membrane against lipoperoxidation, but did not prevent the binding of proteins to the erythrocyte membrane. Moreover, the antioxidant (+-catechin, which also failed to prevent the cross-linking of cytoskeletal proteins with Hb, was very effective in protecting erythrocyte ghosts from lipid peroxidation induced by the Fenton reaction. This study also showed that EPR spectroscopy can be useful to assess the molecular dynamics of red blood cell membranes in both the lipid and protein domains and examine oxidation processes in a system that is so vulnerable to oxidation.

  20. Azide protection of bacteroides superoxide dismutases from inactivation by hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Barkley, K.B.; Gregory, E.M.

    1986-05-01

    The anaerobes Bacteroides fragilis, B. distasonis and B. thetaiotaomicron produce an iron-containing superoxide dismutase (FeSOD). These FeSODs are reversibly inhibited by 1 mM azide (NaN/sub 3/) and are irreversibly inactivated upon incubation with hydrogen peroxide (H/sub 2/O/sub 2/). H/sub 2/O/sub 2/ inactivation of the enzyme likely depends on a Fenton type reaction with the production of hydroxyl radical (OH). Addition of NaN/sub 3/ to the enzyme solution decreased the rate of inactivation by H/sub 2/O/sub 2/. After 20 minutes incubation of purified B. distasonis FeSOD with 2.5 mM H/sub 2/O/sub 2/, 61% of the initial enzymatic activity remained when 1 mM NaN/sub 3/ was also present compared with 29% activity without NaN/sub 3/. Similar results were seen with FeSOD from B. fragilis and B. thetaiotaomicron. Metal analyses of the native, peroxidized, and NaN/sub 3/ protected samples are consistent with loss of Fe from the enzyme upon peroxidation, but retention of Fe and enzymatic activity in the NaN/sub 3/ protected sample. Protection of FeSOD activity from H/sub 2/O/sub 2/ inactivation was dependent on NaN/sub 3/ concentration. Anionic hydroxyl radical scavengers, such as urate and xanthine did not significantly protect the enzyme. The results are consistent with binding of azide to the active site either preventing entry of H/sub 2/O/sub 2/ or altering Fe redox potential, preventing OH production.

  1. Borate-catalyzed reactions of hydrogen peroxide: kinetics and mechanism of the oxidation of organic sulfides by peroxoborates.

    Science.gov (United States)

    Davies, D Martin; Deary, Michael E; Quill, Kieran; Smith, Robert A

    2005-06-06

    The kinetics of the oxidation of substituted phenyl methyl sulfides by hydrogen peroxide in borate/boric acid buffers were investigated as a function of pH, total peroxide concentration, and total boron concentration. Second-order rate constants at 25 degrees C for the reaction of methyl 4-nitrophenyl sulfide and H(2)O(2), monoperoxoborate, HOOB(OH)(3) (-), or diperoxoborate, (HOO)(2)B(OH)(2) (-), are 8.29 x 10(-5), 1.51 x 10(-2) and 1.06 x 10(-2) M(-1) s(-1), respectively. Peroxoboric acid, HOOB(OH)(2), is unreactive. The Hammett rho values for the reactions of a range of substituted phenyl methyl sulfides and hydrogen peroxide, monoperoxoborate or diperoxoborate are -1.50 +/- 0.1, -0.65 +/- 0.07 and -0.48 (two points only), respectively. The rho values for the peroxoborates are of significantly lower magnitude than expected from their reactivity compared to other peroxides. Nevertheless the negative rho values indicate positive charge development on the sulfur atom in the transition state consistent with nucleophilic attack by the organic sulfides on the peroxoborates as with the other peroxides. The kinetic parameters, including the lack of reactivity of peroxoboric acid, are discussed in terms of the differences in the transition state of reactions involving peroxoboron species with respect to those of other peroxides.

  2. Enamel properties after tooth bleaching with hydrogen/carbamide peroxides in association with a CPP-ACP paste.

    Science.gov (United States)

    de Vasconcelos, Adriana Alcantara Meira; Cunha, Ana Gabriela Gama; Borges, Boniek Castillo Dutra; Vitoriano, Jussier de Oliveira; Alves-Júnior, Clodomiro; Machado, Cláudia Tavares; dos Santos, Alex José Souza

    2012-07-01

    This study evaluated the impact of bleaching teeth using blends of a CPP-ACP paste (MI Paste; MI) and carbamide/hydrogen peroxides in different proportions on surface properties of bleached enamel. Ninety bovine incisors were bleached with 7.5% hydrogen peroxide (HP), 16% carbamide peroxide (CP), MI and blends of HP or CP:MI at three proportions (1:1, 2:1, 1:2). Hardness and roughness were measured at baseline and after bleaching. Enamel morphology was evaluated by Scanning Electron Microscopy (SEM). The data were analyzed by two-way ANOVA for repeated measurements and Tukey's test. Most of the samples bleached with MI in combination with peroxides presented increased hardness and roughness which were associated to mineral deposition, as observed by SEM images. Blends with higher fractions of MI did not offer superior benefits. The use of a CPP-ACP paste mixed to carbamide/hydrogen peroxides can decrease adverse side-effects from tooth bleaching on an enamel surface.

  3. An in vitro thermal analysis during different light-activated hydrogen peroxide bleaching

    Science.gov (United States)

    Kabbach, W.; Zezell, D. M.; Bandéca, M. C.; Pereira, T. M.; Andrade, M. F.

    2010-09-01

    This study measured the critical temperature reaching time and also the variation of temperature in the surface of the cervical region and within the pulp chamber of human teeth submitted to dental bleaching using 35% hydrogen peroxide gel activated by three different light sources. The samples were randomly divided into 3 groups ( n = 15), according to the catalyst light source: Halogen Light (HL), High Intensity Diode Laser (DL), and Light Emmited Diode (LED). The results of temperature variation were submitted to the analysis of variance and Tukey test with p bleaching for a short period of time. The LED source did not heat the target tissues significantly within the parameters used in this study.

  4. Decomposition of acetone by hydrogen peroxide/ozone process in a rotating packed contactor.

    Science.gov (United States)

    Ku, Young; Huang, Yun-Jen; Chen, Hua-Wei; Hou, Wei-Ming

    2011-07-01

    The direct use of ozone (O3) in water and wastewater treatment processes is found to be inefficient, incomplete, and limited by the ozone transfer between the gas-liquid interface because of its low solubility and instability in aqueous solutions. Therefore, rotating packed contactors were introduced to improve the transfer of ozone from the gaseous phase to the solution phase, and the effect of several reaction parameters were investigated on the temporal variations of acetone concentration in aqueous solution. The decomposition rate constant of acetone was enhanced by increasing the rotor speed from 450 to 1800 rpm. Increasing the hydrogen peroxide (H2O2)/O3 molar ratios accelerated the decomposition rate until a certain optimum H2O2/O3 molar ratio was reached; further addition of H2O2 inhibited the decomposition of acetone, possibly because excessive amounts of H2O2 added might serve as a scavenger to deplete hydroxyl free radicals.

  5. Interaction Between Titanium Implant Surfaces and Hydrogen Peroxide in Biologically Relevant Environments

    Energy Technology Data Exchange (ETDEWEB)

    Muyco, J; Ratto, T

    2004-04-21

    Titanium was exposed to dilute solutions of hydrogen peroxide (H2O2) to better characterize the interaction at the interface between the solution and metal. The intensity of light passing through films of known thickness of titanium on quartz was measured as a function of time in contact with H{sub 2}O{sub 2} in concentrations of 0.3% and 1.0%. An atomic force microscope (AFM) was used to record deflection-distance (force) curves as a probe approached the interface of titanium in contact with solution containing 0.3% of H{sub 2}O{sub 2}. The interaction layer measured using AFM techniques was much greater than the thickness of the titanium films used in this study. Raman spectroscopy taken during interaction shows the emergence of a Ti-peroxy gel and titania after 2 hours in contact with 0.3% H2O2 solution.

  6. A passive apparatus for controlled-flux delivery of biocides: hydrogen peroxide as an example

    DEFF Research Database (Denmark)

    Olsen, Stefan Møller; Pedersen, L.T.; Dam-Johansen, Kim

    2010-01-01

    A new test method has been developed to estimate the required release rate of hydrogen peroxide (H2O2) to prevent marine biofouling. The technique exploits a well-defined concentration gradient of biocide across a cellulose acetate membrane. A controlled flux of H2O2, an environmentally friendly...... biocide, was obtained. Larvae of the barnacle, Balanus improvisus, were subjected to known release rates of H2O2 from a surface, under laboratory conditions. It was found that the distribution of settled larvae was not significantly different from the controls when H2O2 fluxes of 5-8 mu g cm(-2) day(-1......) were applied. However, release rates of 40 mu g cm(-2) day(-1) significantly displaced the distribution of settled larvae towards the area of the chamber farthest away from the membrane. Membrane tests in seawater (Jyllinge Harbour, Denmark) for over 16 weeks showed that release rates of H2O2...

  7. Bactericidal effect of plasma jet with helium flowing through 3% hydrogen peroxide against Enterococcus faecalis

    Science.gov (United States)

    Zhou, Xin-Cai; Li, Yu-Lan; Liu, De-Xi; Cao, Ying-Guang; Lu, Xin-Pei

    2016-01-01

    The aim of the present study was to assess the antimicrobial activity of plasma jet with helium (He) flowing through 3% hydrogen peroxide in root canals infected with Enterococcus faecalis. A total of 42 single-rooted anterior teeth were prepared, sterilized, inoculated with an E. faecalis suspension and incubated for 7 days. Next, the teeth were randomly divided into six experimental groups (including groups treated by plasma jet with or without He for different time durations) and one control group treated without plasma. The number of surviving bacteria in each canal was determined by counting the colony forming units (CFU)/ml on nutrient agar plates. The results indicated that statistically significant reduction in CFU/ml (Pfaecalis and should be considered as an alternative method for root canal disinfection in endodontic treatments. PMID:27882119

  8. Degradation and effect of hydrogen peroxide in small-scale recirculation aquaculture system biofilters

    DEFF Research Database (Denmark)

    Møller, Martin Sune; Arvin, Erik; Pedersen, Lars-Flemming

    2010-01-01

    From an environmental point of view, hydrogen peroxide (HP) has beneficial attributes compared with other disinfectants in terms of its ready degradation and neutral by-products. The rapid degradation of HP can, however, cause difficulties with regard to safe and efficient water treatment when...... applied in different systems. In this study, we investigated the degradation kinetics of HP in biofilters from water recirculating aquaculture systems (RAS). The potential effect of HP on the nitrification process in the biofilters was also examined. Biofilter elements from two different pilot-scale RAS...... were exposed to various HP treatments in batch experiments, and the HP concentration was found to follow an exponential decay. The biofilter ammonia and nitrite oxidation processes showed quick recuperation after exposure to a single dose of HP up to 30 mg L−1. An average HP concentration of 10–13 mg L...

  9. Fabrication of a novel electrochemical sensor for determination of hydrogen peroxide in different fruit juice samples

    OpenAIRE

    Nasirizadeh, Navid; Shekari, Zahra; Nazari, Ali; Tabatabaee, Masoumeh

    2016-01-01

    A new hydrogen peroxide (H2O2) sensor is fabricated based on a multiwalled carbon nanotube-modified glassy carbon electrode (MWCNT-GCE) and reactive blue 19 (RB). The charge transfer coefficient, α, and the charge transfer rate constant, ks, of RB adsorbed on MWCNT-GCE were calculated and found to be 0.44 ± 0.01 Hz and 1.9 ± 0.05 Hz, respectively. The catalysis of the electroreduction of H2O2 by RB-MWCNT-GCE is described. The RB-MWCNT-GCE shows a dramatic increase in the peak current and a de...

  10. Ratiometric Sensing of Hydrogen Peroxide Utilizing Conformational Change in Fluorescent Boronic Acid Polymers

    Directory of Open Access Journals (Sweden)

    Kan Takeshima

    2017-01-01

    Full Text Available We demonstrate that the copolymers containing boronic acid and pyrene units can be utilized for the fluorometric sensing of hydrogen peroxide (H2O2 in aqueous solutions. The copolymer exists in a relatively extended conformation in the absence of H2O2, whereas the polymer chain is contracted by the reaction of boronic acid moieties with H2O2 to form phenol groups. This conformational change induces aggregation of the originally isolated pyrene groups. As a result, relative intensity of excimer emission with respect to monomer emission increases with H2O2 concentration. Accordingly, the present methodology enables us to measure H2O2 by means of ratiometric fluorescence change in the range of 0–30 μM.

  11. Controllable pneumatic generator based on the catalytic decomposition of hydrogen peroxide.

    Science.gov (United States)

    Kim, Kyung-Rok; Kim, Kyung-Soo; Kim, Soohyun

    2014-07-01

    This paper presents a novel compact and controllable pneumatic generator that uses hydrogen peroxide decomposition. A fuel micro-injector using a piston-pump mechanism is devised and tested to control the chemical decomposition rate. By controlling the injection rate, the feedback controller maintains the pressure of the gas reservoir at a desired pressure level. Thermodynamic analysis and experiments are performed to demonstrate the feasibility of the proposed pneumatic generator. Using a prototype of the pneumatic generator, it takes 6 s to reach 3.5 bars with a reservoir volume of 200 ml at the room temperature, which is sufficiently rapid and effective to maintain the repetitive lifting of a 1 kg mass.

  12. Trichloroethylene degradation in a coupled anaerobic/aerobic reactor oxygenated using hydrogen peroxide.

    Science.gov (United States)

    Tartakovsky, B; Manuel, M F; Guiot, S R

    2003-12-15

    In this work, trichloroethylene (TCE) degradation under combined anaerobic-aerobic conditions was studied in an ethanol-fed biofilm reactor oxygenated using hydrogen peroxide. The reactor was inoculated with a biomass originating from an anaerobic digestor. Granulated peat was added to the reactor as a substratum for biofilm development. Extensive characterization of reactor populations using activity tests and PCR analysis revealed the development of a mutualistic consortium, particularly methanotrophic and methanogenic microorganisms. This consortium was shown to degrade TCE by a combination of reductive and oxidative pathways. A near complete degradation of TCE at a load of 18 mg L(R)(-1) day(-1) was evidenced by a stoichiometric release of inorganic chloride.

  13. Treatment of oil refinery wastewater using crude Coprinus cinereus peroxidase and hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Ikehata, K.; Buchanan, I. D.; Smith, D. W. [University of Alberta, Dept. of Civil and Environmental Engineering, Edmonton, AB (Canada)

    2003-11-01

    Enzymatic treatment of oil refinery wastewater was investigated using crude peroxidase derived from the fungus Coprinus cinereus (CIP), and hydrogen peroxide. Further objectives were to investigate the effects of residual organic compounds in the crude enzyme, and compare the performance of CIP to those of purified horseradish peroxidase (HRP) and Arthromyces ramosus peroxidase (ARP) in the treatment of a strong refinery wastewater. Phenols in the wastewater were converted to coloured polymeric products and then removed by coagulation with alum. As a result of the enzymatic treatment and alum coagulation of the wastewater containing 6.4 mM total phenol, the chemical oxygen demand and the 5-d biochemical oxygen demand were reduced by 52 per cent and 58 per cent, respectively. Reduction of the oxygen demands notwithstanding, the dissolved organic materials in the crude CIP were not affected by either of these processes and tended to remain in the treated wastewater. 31 refs., 1 tab., 7 figs.

  14. Determination of hydrogen peroxide in reactor moderator solutions by flow injection analysis

    Energy Technology Data Exchange (ETDEWEB)

    Whitaker, M.J.

    1991-12-31

    A flow injection analysis (FIA) method for the determination of hydrogen peroxide in reactor moderator water was developed and installed at the Savannah River Site (SRS) Water Quality Laboratory. The technique has an analytical range of 0.10 to 2.50 ppm (ug/mL) with a sampling rate of 40 samples per hour. The calibration curve is linear with a correlation coefficient of 0.999, and the precision is excellent with relative standard deviations at the 0.50% level for both 0.10 and 2.50 ppm standards. When the automated FIA procedure is compared to the manual method it demonstrates a twenty minute reduction in analysis time per sample, and the total liquid waste generated per sample analyzed is reduced by roughly 95 mL. 6 refs., 10 figs., 6 tabs.

  15. Determination of hydrogen peroxide in reactor moderator solutions by flow injection analysis

    Energy Technology Data Exchange (ETDEWEB)

    Whitaker, M.J.

    1991-01-01

    A flow injection analysis (FIA) method for the determination of hydrogen peroxide in reactor moderator water was developed and installed at the Savannah River Site (SRS) Water Quality Laboratory. The technique has an analytical range of 0.10 to 2.50 ppm (ug/mL) with a sampling rate of 40 samples per hour. The calibration curve is linear with a correlation coefficient of 0.999, and the precision is excellent with relative standard deviations at the 0.50% level for both 0.10 and 2.50 ppm standards. When the automated FIA procedure is compared to the manual method it demonstrates a twenty minute reduction in analysis time per sample, and the total liquid waste generated per sample analyzed is reduced by roughly 95 mL. 6 refs., 10 figs., 6 tabs.

  16. Antibacterial synergistic effect of chlorhexidine and hydrogen peroxide against Streptococcus sobrinus, Streptococcus faecalis and Staphylococcus aureus.

    Science.gov (United States)

    Steinberg, D; Heling, I; Daniel, I; Ginsburg, I

    1999-02-01

    Chlorhexidine (CHX) and Hydrogen peroxide (HP) are potent antibacterial agents that are used in controlling dental plaque. However, both agents bear undesired side-effects. We have tested the hypothesis that an antibacterial synergistic effect can occur between the two agents against Streptococcus sobrinus, Streptococcus faecalis and Staphylococcus aureus. We have found that at several combinations of HP and CHX an antibacterial synergistic effect does occur, while at other combinations a on-significant synergism was noticed. No antagonism between the two agents was found in our experimental system. It can be postulated that the mechanism of this synergistic effect is via alteration of the bacterial cell-surface by CHX thereby allowing for an increased amount of HP to penetrate and to react with the intercellular organelles of the bacteria. These results suggest that CHX and HP can be of use in controlling the dental plaque in the oral cavity.

  17. Hydrogen peroxide as a damage signal in tissue injury and inflammation: Murderer, mediator, or messenger?

    Science.gov (United States)

    van der Vliet, Albert; Janssen-Heininger, Yvonne M. W.

    2015-01-01

    Tissue injury and inflammation are associated with increased production of reactive oxygen species (ROS), which have the ability to induce oxidative injury to various biomolecules resulting in e.g. protein dysfunction or cell death. However, recent observations indicate that formation of hydrogen peroxide (H2O2) during tissue injury is also an essential feature of the ensuing wound healing response, and functions as an early damage signal to control several critical aspects of the wound healing process. Because innate oxidative wound responses must be tightly coordinated to avoid chronic inflammation or tissue injury, a more complete understanding is needed regarding the origins and dynamics of ROS production, and their critical biological targets. This Prospect highlights the current experimental evidence implicating H2O2 in early epithelial wound responses, and summarizes technical advances and approaches that may help distinguish its beneficial actions from its more deleterious actions in conditions of chronic tissue injury or inflammation. PMID:24122865

  18. Preparation of pristine graphene in ethanol assisted by organic salts for nonenzymatic detection of hydrogen peroxide.

    Science.gov (United States)

    Hou, Bingjie; Liu, Huaizhi; Qi, Shaopeng; Zhu, Yinyan; Zhou, Bo; Jiang, Xiaoqing; Zhu, Lihua

    2018-01-15

    High quality pristine graphene (PG) dispersions are prepared conveniently via an organic salts assisted exfoliation method in a green, non-toxic, cheap and low boiling point solvent: ethanol. The PG is characterized by transmission electron microscopy and atomic force microscopy. Furthermore, the PG is used as an electrode material for fabrication of nonenzymatic sensor of hydrogen peroxide (H2O2). This nonenzymatic sensor shows enhanced electrocatalytic activity towards H2O2 and displays two linear ranges from 2.0 to 37.0μM and 37.0 to 437.0μM with a detection limit of 0.19μM (S/N=3), which is comparable to those electrochemical sensors based on metal oxide or noble metal/graphene composites. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Schottky Photodiode Fabricated from Hydrogen-Peroxide-Treated ZnO Nanowires

    Science.gov (United States)

    Lee, Hsin-Yen; Wu, Bin-Kun; Chern, Ming-Yau

    2013-05-01

    An effective, transparent solar-blind Schottky ultraviolet (UV) sensor made of zinc oxide (ZnO) nanowires (NWs) was fabricated by chemical vapor deposition (CVD). Indium-tin oxide (ITO) thin films were deposited by radio frequency (RF) sputtering as Schottky contacts, where the hydrogen peroxide (H2O2) treatment of ZnO NWs played a key role in the rectifying effect. The photodiode showed a fitted barrier height of 0.89 eV, an ideality factor of 1.82, and a rectification behavior of up to three orders of magnitude at a voltage bias between -1 and +1 V. Photoresponse measurement proved a reliable device in the UV region.

  20. Roles of Catalase and Trehalose in the Protection from Hydrogen Peroxide Toxicity in Saccharomyces cerevisiae.

    Science.gov (United States)

    Nishimoto, Takuto; Watanabe, Takeru; Furuta, Masakazu; Kataoka, Michihiko; Kishida, Masao

    2016-01-01

    The roles of catalase and trehalose in Saccharomyces cerevisiae subject to hydrogen peroxide (H2O2) treatment were examined by measuring the catalase activity and intracellular trehalose levels in mutants lacking catalase or trehalose synthetase. Intracellular trehalose was elevated but the survival rate after H2O2 treatment remained low in mutants with deletion of the Catalase T gene. On the other hand, deletion of the trehalose synthetase gene increased the catalase activity in mutated yeast to levels higher than those in the wild-type strain, and these mutants exhibited some degree of tolerance to H2O2 treatment. These results suggest that Catalase T is critical in the yeast response to oxidative damage caused by H2O2 treatment, but trehalose also plays a role in protection against H2O2 treatment.

  1. Mediatorless Impedance Studies with Titanium Dioxide Conjugated Gold Nanoparticles for Hydrogen Peroxide Detection

    Directory of Open Access Journals (Sweden)

    Nur Hamidah Abdul Halim

    2017-09-01

    Full Text Available An impedimetric-based biosensor constructed using gold nanoparticles (AuNP entrapped within titanium dioxide (TiO2 particles for hydrogen peroxide (H2O2 detection is the main feature of this research. The matrix of the biosensor employed the surface of TiO2, which was previously modified with an amine terminal group using 3-Aminopropyltriethoxysilane (APTS at a low temperature to create a ready to immobilise surface for the biosensor application. Hemoglobin (Hb, which exhibits peroxidase-like activity, was used as the bioreceptor in the biosensor to detect H2O2 in solution. The analysis was carried out using an alternative impedance method, in which the biosensor exhibited a wide linear range response between 1 × 10−4 M and 1.5 × 10−2 M and a limit of detection (LOD of 1 × 10−5 M without a redox mediator.

  2. Silymarin inhibits cisplatin-mediated apoptosis via inhibition of hydrogen peroxide and hydroxyl radical generation

    Directory of Open Access Journals (Sweden)

    Angkana Tantituvanont

    2015-04-01

    Full Text Available Cisplatin mediated nephrotoxicity has been continuously reported and recognized as a major obstacle for cisplatinbased chemotherapy. The present study aimed to demonstrate the potential use of silymarin, an extract from the seed of Silybum marianum L., as a combination therapy with cisplatin. Previous studies indicated that cisplatin-mediated toxicity was primarily caused by cellular oxidative stress. This study found that pretreatment with silymarin significantly attenuated oxidative stress induced by cisplatin in human renal epithelial cells (HK2-cells and protected against cisplatin-mediated apoptosis. Moreover, the present study demonstrated that silymarin could attenuate hydrogen peroxide and hydroxyl radical generated by cisplatin while having minimal effect on superoxide anion level. In summary, these observation showed significant impact of silymarin in the inhibition of cisplatin-mediated renal cell death in vitro and could be beneficial for the development of this compound as a combination therapy in patients before receiving cisplatin.

  3. Intracellular signaling by diffusion: can waves of hydrogen peroxide transmit intracellular information in plant cells?

    DEFF Research Database (Denmark)

    Vestergaard, Christian L.; Flyvbjerg, Henrik; Møller, Ian Max

    2012-01-01

    Amplitude- and frequency-modulated waves of Ca(2+) ions transmit information inside cells. Reactive Oxygen Species (ROS), specifically hydrogen peroxide, have been proposed to have a similar role in plant cells. We consider the feasibility of such an intracellular communication system in view...... which diffusion-mediated signaling is possible. We show that purely diffusive transmission of intracellular information by H(2)O(2) over a distance of 1 μm (typical distance between organelles, which may function as relay stations) is possible at frequencies well above 1 Hz, which is the highest......, at this longer distance a high rate of enzymatic degradation is required to make signaling at frequencies above 0.1 Hz possible. In either case, cytoplasmic streaming does not seriously disturb signals. We conclude that although purely diffusion-mediated signaling without relaying stations is theoretically...

  4. Antifouling character of 'active' hybrid xerogel coatings with sequestered catalysts for the activation of hydrogen peroxide.

    Science.gov (United States)

    McMaster, Danielle M; Bennett, Stephanie M; Tang, Ying; Finlay, John A; Kowalke, Gregory L; Nedved, Brian; Bright, Frank V; Callow, Maureen E; Callow, James A; Wendt, Dean E; Hadfield, Michael G; Detty, Michael R

    2009-01-01

    Halide-permeable xerogel films prepared from sols containing 50 mol% aminopropyltriethoxysilane (APTES)/50 mol% tetraethoxysilane (TEOS) or 10 mol% APTES/90 mol% TEOS and 0.015 M selenoxide or telluride catalyst in the sol gave reduced settlement of cypris larvae of the barnacle Balanus amphitrite and larvae of the tubeworm Hydroides elegans in the presence of artificial seawater (ASW) and hydrogen peroxide (5-100 microM) relative to glass controls. Settlement of Ulva zoospores was lower on both the 50 mol% APTES/50 mol% TEOS and 10 mol% APTES/90 mol% TEOS xerogel formulations in comparison with glass controls with or without the added catalyst. The 50 mol% APTES/50 mol%TEOS xerogel containing telluride catalyst gave reduced settlement of Ulva zoospores in the presence of 100 microM H(2)O(2) in ASW compared with the same coating without added peroxide. Scanning electron microscopy and XPS data suggest that exposure to H(2)O(2) does not lead to chemical or morphological changes on the xerogel surface.

  5. Effects of hydrogen peroxide on dental unit biofilms and treatment water contamination.

    Science.gov (United States)

    Lin, Shih-Ming; Svoboda, Kathy K H; Giletto, Anthony; Seibert, Jeff; Puttaiah, Raghunath

    2011-01-01

    To study effects of various concentrations of hydrogen peroxide on mature waterline biofilms and in controlling planktonic (free-floating) organisms in simulated dental treatment water systems; and to study in vitro the effects of 2%, 3%, and 7% hydrogen peroxide on the removal of mature biofilms and inorganic compounds in dental waterlines. Four units of an automated dental unit water system simulation device was used for 12 weeks. All units were initially cleaned to control biofilms and inorganic deposits. H2O(2) at concentrations of 1%, 2%, 3% was used weekly for periodic cleaning in three treatment group units (units 1, 2 & 3), with 0.05%, 0.15% and 0.25% H(2)O(2) in municipal water used as irrigant respectively. The control unit (unit 4) did not have weekly cleanings and used municipal water as irrigant. Laser Scanning Confocal Microscopy and Scanning Electron Microscopy were used to study deposits on lines, and weekly heterotrophic plate counts done to study effluent water contamination. A 24 hour in vitro challenge test with 7%, 3% and 2% H(2)O(2) on mature biofilms was conducted using harvested waterlines to study biofilm and inorganic deposit removal. Heterotrophic plate counts of effluent water showed that the control unit reached contamination levels in excess of 400,000 CFU/mL while all treatment units showed contamination levels irrigation was beneficial in controlling biofilm and planktonic contamination in dental unit water systems. However, to remove well established biofilms, it may take more than 2 months when initial and multiple periodic cleanings are performed using H(2)O(2).

  6. Quantum dot-based FRET for sensitive determination of hydrogen peroxide and glucose using tyramide reaction.

    Science.gov (United States)

    Huang, Xiangyi; Wang, Jinjie; Liu, Heng; Lan, Tao; Ren, Jicun

    2013-03-15

    In this paper, we report a new strategy for detection of hydrogen peroxide and glucose using quantum dot (QD)-based fluorescence resonance energy transfer (FRET) and tyramide reaction. The principle of FRET is based on highly sensitive reaction of a carbocyanine dye (Cy5) labeled tyramide and hydrogen peroxide catalyzed by horseradish peroxidase (HRP), and the fluorescence spectrum of QDs (EXmax 605 nm) partially overlaps with the absorption bands of Cy5. We firstly conjugated HRP to QDs, and then demonstrated an efficient FRET between HRP conjugated QDs (as energy donors) and tyramide labeled Cy5 (as energy acceptors) due to the formation of Cy5-labeled HRP-QDs assemblies in the presence of H₂O₂. We observed that the fluorescence Cy5 depended linearly on the H₂O₂ concentration within a range of concentration from 10 to 100 nM and the detection limit of this assay was 10 nM. Based on the principle for determination of H₂O₂, we develop a new strategy for assay of glucose by coupling with glucose oxidase-mediated reaction. The established methods were successfully used for determination of glucose levels in human sera, and the results obtained were in good agreement with commercially available method. Our method is at least 1 order of magnitude more sensitive than in the commercially available method. More importantly, our method described here can be extended to other assay designs using different oxidase enzymes, energy donors and energy acceptors, such as near-infrared (NIR)-to-visible upconversion nanoparticles and silicon and carbon QDs. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. A luminescence-based probe for sensitive detection of hydrogen peroxide in seconds

    Energy Technology Data Exchange (ETDEWEB)

    Zscharnack, Kristin; Kreisig, Thomas; Prasse, Agneta A. [Institute of Bioanalytical Chemistry, Faculty of Chemistry and Mineralogy, Universität Leipzig, Deutscher Platz 5, Leipzig 04103 (Germany); Zuchner, Thole, E-mail: zuechner@rz.uni-leipzig.de [Institute of Bioanalytical Chemistry, Faculty of Chemistry and Mineralogy, Universität Leipzig, Deutscher Platz 5, Leipzig 04103 (Germany); Center for Biotechnology and Biomedicine, Universität Leipzig, Deutscher Platz 5, Leipzig 04103 (Germany)

    2014-06-27

    Highlights: • We describe a novel probe for the sensitive detection of H{sub 2}O{sub 2}. • H{sub 2}O{sub 2} quenches the luminescence of a complex consisting of phthalic acid and terbium ions. • A stable fluorescence signal is generated immediately after mixing probe and sample. • The PATb probe detects H{sub 2}O{sub 2} over four orders of magnitude. - Abstract: Here, we present a fast and simple hydrogen peroxide assay that is based on time-resolved fluorescence. The emission intensity of a complex consisting of terbium ions (Tb{sup 3+}) and phthalic acid (PA) in HEPES buffer is quenched in the presence of H{sub 2}O{sub 2} and this quenching is concentration-dependent. The novel PATb assay detects hydrogen peroxide at a pH range from 7.5 to 8.5 and with a detection limit of 150 nmol L{sup −1} at pH 8.5. The total assay time is less than 1 min. The linear range of the assay can be adapted by a pH adjustment of the aqueous buffer and covers a concentration range from 310 nmol L{sup −1} to 2.56 mmol L{sup −1} in total which encompasses four orders of magnitude. The assay is compatible with high concentrations of all 47 tested inorganic and organic compounds. The PATb assay was applied to quantify H{sub 2}O{sub 2} in polluted river water samples. In conclusion, this fast and easy-to-use assay detects H{sub 2}O{sub 2} with high sensitivity and precision.

  8. Facile synthesis of flower like copper oxide and their application to hydrogen peroxide and nitrite sensing

    Directory of Open Access Journals (Sweden)

    Zhang Li

    2011-12-01

    Full Text Available Abstract Background The detection of hydrogen peroxide (H2O2 and nitrite ion (NO2- is of great important in various fields including clinic, food, pharmaceutical and environmental analyses. Compared with many methods that have been developed for the determination of them, the electrochemical detection method has attracted much attention. In recent years, with the development of nanotechnology, many kinds of micro/nano-scale materials have been used in the construction of electrochemical biosensors because of their unique and particular properties. Among these catalysts, copper oxide (CuO, as a well known p-type semiconductor, has gained increasing attention not only for its unique properties but also for its applications in many fields such as gas sensors, photocatalyst and electrochemistry sensors. Continuing our previous investigations on transition-metal oxide including cuprous oxide and α-Fe2O3 modified electrode, in the present paper we examine the electrochemical and electrocatalytical behavior of flower like copper oxide modified glass carbon electrodes (CuO/GCE. Results Flower like copper oxide (CuO composed of many nanoflake was synthesized by a simple hydrothermal reaction and characterized using field-emission scanning electron microscopy (FE-SEM and X-ray diffraction (XRD. CuO modified glass carbon electrode (CuO/GCE was fabricated and characterized electrochemically. A highly sensitive method for the rapid amperometric detection of hydrogen peroxide (H2O2 and nitrite (NO2- was reported. Conclusions Due to the large specific surface area and inner characteristic of the flower like CuO, the resulting electrode show excellent electrocatalytic reduction for H2O2 and oxidation of NO2-. Its sensitivity, low detection limit, fast response time and simplicity are satisfactory. Furthermore, this synthetic approach can also be applied for the synthesis of other inorganic oxides with improved performances and they can also be extended to

  9. Chronic lead exposure decreases the vascular reactivity of rat aortas: the role of hydrogen peroxide.

    Directory of Open Access Journals (Sweden)

    Karolini Zuqui Nunes

    Full Text Available We investigated whether exposure to small concentrations of lead alters blood pressure and vascular reactivity. Male Wistar rats were sorted randomly into the following two groups: control (Ct and treatment with 100 ppm of lead (Pb, which was added to drinking water, for 30 days. Systolic blood pressure (BP was measured weekly. Following treatment, aortic ring vascular reactivity was assessed. Tissue samples were properly stored for further biochemical investigation. The lead concentration in the blood reached approximately 8 μg/dL. Treatment increased blood pressure and decreased the contractile responses of the aortic rings to phenylephrine (1 nM-100 mM. Following N-nitro-L arginine methyl ester (L-NAME administration, contractile responses increased in both groups but did not differ significantly between them. Lead effects on Rmax were decreased compared to control subjects following superoxide dismutase (SOD administration. Catalase, diethyldithiocarbamic acid (DETCA, and apocynin increased the vasoconstrictor response induced by phenylephrine in the aortas of lead-treated rats but did not increase the vasoconstrictor response in the aortas of untreated rats. Tetraethylammonium (TEA potentiated the vasoconstrictor response induced by phenylephrine in aortic segments in both groups, but these effects were greater in lead-treated rats. The co-incubation of TEA and catalase abolished the vasodilatory effect noted in the lead group. The present study is the first to demonstrate that blood lead concentrations well below the values established by international legislation increased blood pressure and decreased phenylephrine-induced vascular reactivity. The latter effect was associated with oxidative stress, specifically oxidative stress induced via increases in hydrogen peroxide levels and the subsequent effects of hydrogen peroxide on potassium channels.

  10. Hydrogen-bearing iron peroxide and the origin of ultralow-velocity zones

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jin; Hu, Qingyang; Kim, Duck Young; Wu, Zhongqing; Wang, Wenzhong; Xiao, Yuming; Chow, Paul; Meng, Yue; Prakapenka, Vitali B.; Mao, Ho-Kwang; Mao, Wendy L. (Stanford); (UST - China); (CIW); (UC); (CHPSTAR- China)

    2017-11-22

    Ultralow-velocity zones (ULVZs) at Earth’s core–mantle boundary region have important implications for the chemical composition and thermal structure of our planet, but their origin has long been debated1,2,3. Hydrogen-bearing iron peroxide (FeO2Hx) in the pyrite-type crystal structure was recently found to be stable under the conditions of the lowermost mantle4,5,6. Using high-pressure experiments and theoretical calculations, we find that iron peroxide with a varying amount of hydrogen has a high density and high Poisson ratio as well as extremely low sound velocities consistent with ULVZs. Here we also report a reaction between iron and water at 86 gigapascals and 2,200 kelvin that produces FeO2Hx. This would provide a mechanism for generating the observed volume occupied by ULVZs through the reaction of about one-tenth the mass of Earth’s ocean water in subducted hydrous minerals with the effectively unlimited reservoir of iron in Earth’s core. Unlike other candidates for the composition of ULVZs7,8,9,10,11,12, FeO2Hx synthesized from the superoxidation of iron by water would not require an extra transportation mechanism to migrate to the core–mantle boundary. These dense FeO2Hx-rich domains would be expected to form directly in the core–mantle boundary region and their properties would provide an explanation for the many enigmatic seismic features that are observed in ULVZs.

  11. Degradation of chitosan by gamma ray with presence of hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Mahmud, Maznah; Yacob, Norzita; Talip, Norhashidah; Abdullah, Zahid [Malaysian Nuclear Agency, Radiation Technology Division, Bangi, 43000 Kajang, Selangor (Malaysia); Naziri, Muhammad Ihsan [University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2014-02-12

    The radiation degraded chitosan samples were prepared by swelling the chitosan powder in water and exposed for gamma irradiation. The ratio chitosan to water was 1:6 with the presence of hydrogen peroxide (H{sub 2}O{sub 2}), 1%–5%. These chitosan-water mixtures were irradiated at 6kGy, which is the lowest irradiation dose that facility can offered. All samples were purified and proceed with characterization. The molecular weight (MW) study was monitored by size exclusion chromatography-multi angle laser light scattering (SEC-MALLS). Results showed that MW of chitosan reduced as the dose increased. Application of H{sub 2}O{sub 2} enhanced the degradation rate of chitosan even at very low irradiation dose. Homogenous degradation also occurred during treatment with H{sub 2}O{sub 2}based on the polydispersity index (PDI) derived from the calculation of weight average molecular weight over number average molecular weight (Mw/Mn). Mechanism of chitosan radiation degradation with and without hydrogen peroxide was also discussed in this paper. Structure of degraded products was characterized with Fourier-transform infrared spectra. The degree of deacetylation (DDA) values of the samples was determined by acid-base titration. Solubility test results showed that, chitosan powder even at low Mw was insoluble in water even at low pH water. Chitosan as well as irradiated chitosan powder are soluble in strong and weak acid solution. Further discussion on behaviours of radiation degraded chitosan will be elaborated more in this paper.

  12. Increased exhalation of hydrogen peroxide in healthy subjects following cigarette consumption

    Directory of Open Access Journals (Sweden)

    Sandra Baltazar Guatura

    2000-07-01

    Full Text Available CONTEXT: Increased hydrogen peroxide has been described in the expired breath condensate (H2O2-E of several lung conditions, such as acute respiratory distress syndrome, chronic obstructive pulmonary disease and asthma. This technique has been advocated as being a simple method for documenting airway inflammation. OBJECTIVE: To evaluate H2O2-E in healthy cigarette smokers, and to determine the acute effects of the consumption of one cigarette on H2O2-E levels. TYPE OF STUDY: Prospective, controlled trial. SETTING: A pulmonary function laboratory in a University Hospital. PARTICIPANTS: Two groups of healthy volunteers: individuals who had never smoked (NS; n=10; 4 men; age = 30.6 ± 6.2 years and current cigarette smokers (S; n=12; 7 men; age = 38.7 ± 9.8. None of the volunteers had respiratory symptoms and all showed normal spirometric tests. INTERVENTION: Expired air was collected from all volunteers through a face mask and a plastic collecting system leading into a flask with dry ice and pure ethanol. Samples from the group S were collected twice, before and half an hour after the combustion of one cigarette. MAIN MEASUREMENTS: Expired hydrogen peroxide using the Gallati and Pracht method. RESULTS: The S and NS groups showed comparable levels of H2O2-E at basal conditions [NS = 0.74 muM (DP 0.24 vs. S = 0.75 muM (DP 0.31]. The smokers showed a significant increase in H2O2-E levels half an hour after the consumption of only one cigarette [0.75 muM (DP 0.31 vs. 0.95 muM (DP 0.22]. CONCLUSION: The present results are consistent with the concept that smokers increase oxidative stress with elevated production of reactive oxygen species, contributing to the development of smoking-related disorders.

  13. Evaluation of a silver-based electrocatalyst for the determination of hydrogen peroxide formed via enzymatic oxidation.

    Science.gov (United States)

    Gonzalez-Macia, Laura; Smyth, Malcolm R; Killard, Anthony J

    2012-09-15

    Silver paste electrodes modified with lyotropic phases formed from dodecyl benzenesulphonic acid and KCl were used as the reductant in the determination of the hydrogen peroxide released from the enzymatic reaction of glucose oxidase with glucose and oxygen. The response of the modified electrode to hydrogen peroxide reduction (-0.1 V vs. Ag/AgCl) was shown to suffer from interference resulting from co-localization of enzyme and substrate at the electrode surface. This interference was eradicated by the introduction of a perm-selective membrane in the form of cellulose acetate. This further facilitated immobilization of the enzyme while allowing diffusion of the generated peroxide to the electrode. The resulting configuration was shown to be capable of the analytical determination of glucose. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Chronic toxicity of hydrogen peroxide to Daphnia magna in a continuous exposure, flow-through test system

    Science.gov (United States)

    Meinertz, J.R.; Greseth, Shari L.; Gaikowski, M.P.; Schmidt, L.J.

    2008-01-01

    A flow-through, continuous exposure test system was developed to expose Daphnia magna to an unstable compound. 35% Perox-Aid?? is a specially formulated hydrogen peroxide (a highly oxidative chemical) product approved for use in U.S. aquaculture and therefore has the potential to be released from aquaculture facilities and pose a risk to aquatic invertebrates. The study objective was to assess the effects of 35% Perox-Aid?? on an aquatic invertebrate by evaluating the survival, growth, production, and gender ratio of progeny from a representative aquatic invertebrate continuously exposed to 35% Perox-Aid??. The study design consisted of 6 treatment groups (10 test chambers each) with target hydrogen peroxide concentrations of 0.0, 0.32, 0.63, 1.25, 2.5, and 5.0??mg L- 1. The study was initiated with effect on Daphnia time to death compared to controls and no significant effect on the time to first brood production and the number of broods produced. Concentrations ??? 0.63??mg L- 1 had no significant effect on the total number of young produced. Concentrations ??? 0.32??mg L- 1 had a negative effect on Daphnia growth. Hydrogen peroxide had no significant effect on the gender ratio of young produced. All second generation Daphnia were female. A continuous discharge of hydrogen peroxide into aquatic ecosystems is not likely to affect cladocerans if the concentration is maintained at ??? 0.63??mg L- 1 for less than 21??days.

  15. Laser Flash Photolysis of Hydrogen Peroxide to Oxidize Protein Solvent-Accessible Residues on the Microsecond Timescale

    National Research Council Canada - National Science Library

    Hambly, David M; Gross, Michael L

    2005-01-01

    ... to unfold, exposing residues that are protected in the native protein. To circumvent this possibility, we developed a method using a 248 nm KrF excimer laser to cleave hydrogen peroxide at low concentrations (15 mM, 0. 04...

  16. Field-controlled electron transfer and reaction kinetics of the biological catalytic system of microperoxidase-11 and hydrogen peroxide

    Directory of Open Access Journals (Sweden)

    Yongki Choi

    2011-12-01

    Full Text Available Controlled reaction kinetics of the bio-catalytic system of microperoxidase-11 and hydrogen peroxide has been achieved using an electrostatic technique. The technique allowed independent control of 1 the thermodynamics of the system using electrochemical setup and 2 the quantum mechanical tunneling at the interface between microperoxidase-11 and the working electrode by applying a gating voltage to the electrode. The cathodic currents of electrodes immobilized with microperoxidase-11 showed a dependence on the gating voltage in the presence of hydrogen peroxide, indicating a controllable reduction reaction. The measured kinetic parameters of the bio-catalytic reduction showed nonlinear dependences on the gating voltage as the result of modified interfacial electron tunnel due to the field induced at the microperoxidase-11-electrode interface. Our results indicate that the kinetics of the reduction of hydrogen peroxide can be controlled by a gating voltage and illustrate the operation of a field-effect bio-catalytic transistor, whose current-generating mechanism is the conversion of hydrogen peroxide to water with the current being controlled by the gating voltage.

  17. Membrane contactor assisted water extraction system for separating hydrogen peroxide from a working solution, and method thereof

    Science.gov (United States)

    Snyder, Seth W [Lincolnwood, IL; Lin, Yupo J [Naperville, IL; Hestekin', Jamie A [Fayetteville, AR; Henry, Michael P [Batavia, IL; Pujado, Peter [Kildeer, IL; Oroskar, Anil [Oak Brook, IL; Kulprathipanja, Santi [Inverness, IL; Randhava, Sarabjit [Evanston, IL

    2010-09-21

    The present invention relates to a membrane contactor assisted extraction system and method for extracting a single phase species from multi-phase working solutions. More specifically one preferred embodiment of the invention relates to a method and system for membrane contactor assisted water (MCAWE) extraction of hydrogen peroxide (H.sub.2O.sub.2) from a working solution.

  18. High performance of hydrogen peroxide detection using Pt nanoparticles-dispersed carbon electrode prepared by pulsed arc plasma deposition.

    Science.gov (United States)

    Ito, Takeshi; Kunimatsu, Masayuki; Kaneko, Satoru; Hirabayashi, Yasuo; Soga, Masayasu; Agawa, Yoshiaki; Suzuki, Koji

    2012-09-15

    We propose novel electrodes with platinum nanoparticles dispersed on a glassy carbon (Pt-NPs/GC) prepared using a pulsed arc plasma deposition (APD) method. The method could coat Pt-NPs on a base material directly with a single-step process in a very short deposition time. The characteristics of the electrodes were discussed in detail. The detection of hydrogen peroxide was performed as an example for application of the electrodes. The distribution of nanoparticles was controlled easily by the number of pulse. The surface morphology changed with the pulse number and the annealing except for the sample prepared by 5 pulses deposition (APD(5)), implying that the APD(5) remained as NPs after the annealing. Average particle size was 2.7 nm on the Pt-NPs/GC. Catalyst activity for oxidizing hydrogen peroxide per Pt loading was excellent on the Pt-NPs/GC. When the Pt-NPs/GC was used as a detector for hydrogen peroxide on a flow injection analysis, the Pt-NPs/GC showed high sensitivity without deterioration. Oxidation current increased linearly with the concentration of hydrogen peroxide from 10nM to 100 μM. This fast and easily prepared electrode showed the capability to replace a conventional bulk metal electrode. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Using a Hands-On Hydrogen Peroxide Decomposition Activity to Teach Catalysis Concepts to K-12 Students

    Science.gov (United States)

    Cybulskis, Viktor J.; Ribeiro, Fabio H.; Gounder, Rajamani

    2016-01-01

    A versatile and transportable laboratory apparatus was developed for middle and high school (6th-12th grade) students as part of a hands-on outreach activity to estimate catalytic rates of hydrogen peroxide decomposition from oxygen evolution rates measured by using a volumetric displacement method. The apparatus was constructed with inherent…

  20. Predictors of local recurrence in high-grade soft tissue sarcomas: hydrogen peroxide as a local adjuvant.

    Science.gov (United States)

    Wooldridge, Adam N; Kolovich, Gregory P; Crist, Martha K; Mayerson, Joel L; Scharschmidt, Thomas J

    2013-02-01

    Soft tissue sarcomas have a mortality rate of 40% to 60%, with local recurrence being a poor prognostic factor for overall survival. Three-percent nondiluted hydrogen peroxide is hypothesized to be an effective local adjuvant. The purpose of this study was to identify risk factors for local recurrence in high-grade soft tissue sarcomas and to determine whether using hydrogen peroxide as a local adjuvant reduced the risks of local recurrence and surgical-site infection. Retrospective data were collected for 106 patients surgically treated for high-grade soft tissue sarcomas between 2002 and 2010. The primary endpoint was local recurrence. Eighteen (16.98%) cases of local recurrence occurred. Predictors of local recurrence were margin status, estimated blood loss, and histology (ie, malignant peripheral nerve sheath tumor), with hazard ratios of 4.44 (95% confidence interval [CI], 1.32-14.95), 1.19 (95% CI, 1.06-1.35), and 9.21 (95% CI, 2.11-40.16), respectively. Hydrogen peroxide yielded a statistically insignificant improvement in local recurrence, with a hazard ratio of 0.81 (95% CI, 0.27-2.48) and a reduced risk of surgical site infection, with a hazard ratio of 0.52 (95% CI, 0.15-1.81). Margin status, increased blood loss, and histologic subtype are associated with increased local recurrence risk. Using hydrogen peroxide improved local control and infection rates, but the difference was not statistically significant. Copyright 2013, SLACK Incorporated.

  1. [The effect of hydrogen peroxide on the electrochemical corrosion properties and metal ions release of nickel-chromium dental alloys].

    Science.gov (United States)

    Wang, Jue; Qiao, Guang-yan

    2013-04-01

    To investigate the effect of hydrogen peroxide on the electrochemical corrosion and metal ions release of nickel-chromium dental alloys. The corrosion resistance of nickel-chromium dental alloys was compared by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curve (PD) methods in artificial saliva after immersed in different concentrations of hydrogen peroxide for 112 h. The metal ions released from nickel-chromium dental alloys to the artificial saliva were detected after electrochemical measurements using inductively coupled plasma mass spectrometry (ICP-MS). The data was statistically analyzed by analysis of variance (ANOVA) using SPSS 13.0 software package. The electrochemical experiment showed that the sequence of polarization resistance in equivalent circuit (Rct), corrosion potential (Ecorr), pitting breakdown potential (Eb), and the difference between Ecorr and Eb representing the "pseudo-passivation" (δE) of nickel-chromium alloys in artificial saliva was 30% corrosion resistance of nickel-chromium dental alloys decrease after immersed in different concentrations of hydrogen peroxide for 112 h. Nickel-chromium dental alloys are more prone to corrosion in the artificial saliva with the concentration of hydrogen peroxide increased, and more metal ions are released in the artificial saliva.

  2. Interference between Streptococcus pneumoniae and Staphylococcus aureus: In Vitro Hydrogen Peroxide-Mediated Killing by Streptococcus pneumoniae

    OpenAIRE

    Regev-Yochay, Gili; Trzciński, Krzysztof; Thompson, Claudette M.; Malley, Richard; Lipsitch, Marc

    2006-01-01

    The bactericidal activity of Streptococcus pneumoniae toward Staphylococcus aureus is mediated by hydrogen peroxide. Catalase eliminated this activity. Pneumococci grown anaerobically or genetically lacking pyruvate oxidase (SpxB) were not bactericidal, nor were nonpneumococcal streptococci. These results provide a possible mechanistic explanation for the interspecies interference observed in epidemiologic studies.

  3. Interference between Streptococcus pneumoniae and Staphylococcus aureus: In Vitro Hydrogen Peroxide-Mediated Killing by Streptococcus pneumoniae

    Science.gov (United States)

    Regev-Yochay, Gili; Trzciński, Krzysztof; Thompson, Claudette M.; Malley, Richard; Lipsitch, Marc

    2006-01-01

    The bactericidal activity of Streptococcus pneumoniae toward Staphylococcus aureus is mediated by hydrogen peroxide. Catalase eliminated this activity. Pneumococci grown anaerobically or genetically lacking pyruvate oxidase (SpxB) were not bactericidal, nor were nonpneumococcal streptococci. These results provide a possible mechanistic explanation for the interspecies interference observed in epidemiologic studies. PMID:16788209

  4. Efficient and selective sulfoxidation by hydrogen peroxide, using a recyclable flavin--[BMIm]PF6 catalytic system.

    Science.gov (United States)

    Lindén, Auri A; Johansson, Mikael; Hermanns, Nina; Bäckvall, Jan-E

    2006-05-12

    A new flavin catalyst 2 immobilized in an ionic liquid ([BMIm]PF6) was used for the highly selective oxidation of sulfides to sulfoxides by hydrogen peroxide. The sulfoxides were obtained in good to high yields and high selectivity without any detectable overoxidation to sulfone. The catalyst in the ionic liquid was recycled up to seven times without loss of activity or selectivity.

  5. Synthesis of tremella-like CoS and its application in sensing of hydrogen peroxide and glucose.

    Science.gov (United States)

    Wu, Wenqin; Yu, Beibei; Wu, Huimin; Wang, Shengfu; Xia, Qinghua; Ding, Yu

    2017-01-01

    Different phases of cobalt sulfides have been fabricated by one-pot hydrothermal method. Comparing all of the prepared materials, and the results revealed that CoS was the most conductive and could accelerate electron transfer. The CoS presented tremella-like and excellent catalytic activities towards hydrogen peroxide and glucose. The sensor based on CoS performed amperometric sensing of hydrogen peroxide in a linear range between 5.00μM and 14.82mM. Meanwhile, sensing of glucose with double-linear range, one is between 5.00μM and 1.10mM, the other is between 1.20mM and 10.20mM. These due to the fact that more and more intermediate species absorb onto electrode surface with increasing the concentration of glucose, which limit the following glucose oxidation. Furthermore, the hydrogen peroxide and glucose sensors based on tremella-like CoS also exhibited excellent selectivity, stability, and reproducibility. Thus, the sensor showed potential utilities in hydrogen peroxide and glucose detection. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Hydrogen peroxide as pre-treatment stressor in experimental immer-sion challenge of rainbow trout fry with Flavobacterium psychrophilum

    DEFF Research Database (Denmark)

    Henriksen, Maya Maria Mihályi; Madsen, Lone; Dalsgaard, Inger

    2012-01-01

    . Non-medical therapeutic substances are routinely used against pathogens in aquacultures, including copper sulphate, chloramine-T, sodium carbonates, sodium chloride, formalin and hydrogen peroxide (H2O2). One of the more successful immersion models used formalin as a stressor, but a less harmful...

  7. The effects of hydrogen peroxide mouthwashes on the prevention of plaque and gingival inflammation: a systematic review.

    NARCIS (Netherlands)

    Hossainian, N.; Slot, D.E.; Afennich, F.; van der Weijden, G.A.

    2011-01-01

    Objectives: The purpose of this review was to describe systematically the effects of hydrogen peroxide mouthwashes as an adjunct to daily oral hygiene or as a mono-therapy in the prevention of plaque accumulation and gingival inflammation. Materials and methods: PubMed-MEDLINE and the

  8. Dilute alkali and hydrogen peroxide treatment of microwave liquefied rape straw residue for the extraction of cellulose nanocrystals

    Science.gov (United States)

    Xingyan Huang; Cornelis F. De Hoop; Feng Li; Jiulong Xie; Chung-Yun Hse; Jinqiu Qi; Yongze Jiang; Yuzhu Chen

    2017-01-01

    Microwave-assisted liquefaction of rape straw in methanol was conducted to collect the liquefied residues for the extraction of cellulose nanocrystals (CNCs).The liquefied residue with content of 23.44% from 180∘C/7.5 min was used to fibrillate CNCs with dilute alkali (2% NaOH) and hydrogen peroxide (5% H2O2...

  9. Time and concentration dependency in the potentially affected fraction of species: the case of hydrogen peroxide treatment of ballast water

    NARCIS (Netherlands)

    Smit, M.G.D.; Ebbens, E.; Jak, R.G.; Huijbregts, M.J.A.

    2008-01-01

    Transport of large volumes of ballast water contributes greatly to invasions of species. Hydrogen peroxide (H2O2) can be used as a disinfectant to prevent the spread of exotic species via ballast water. Instead of using environmental risk assessment techniques for protecting a certain fraction of

  10. Bactericidal Efficacy of Hydrogen Peroxide-Based Disinfectants Against Gram-Positive and Gram-Negative Bacteria on Stainless Steel Surfaces.

    Science.gov (United States)

    Ríos-Castillo, Abel G; González-Rivas, Fabián; Rodríguez-Jerez, José J

    2017-10-01

    In order to develop disinfectant formulations that leverage the effectiveness of hydrogen peroxide (H2 O2 ), this study evaluated the bactericidal efficacy of hydrogen peroxide-based disinfectants against Gram-positive and Gram-negative bacteria on stainless steel surfaces. Low concentration of hydrogen peroxide as 0.5% with a cationic polymer, ethoxylated fatty alcohol, and ethyl alcohol had bactericidal efficacy (reductions ≥ 4 log10 CFU/mL) against Escherichia coli, Staphylococcus aureus, Enterococcus hirae, and Pseudomonas aeruginosa. Hydrogen peroxide-based disinfectants were more effective against E. hirae and P. aeruginosa than to S. aureus. However, the efficacy of hydrogen peroxide against catalase positive bacteria such as S. aureus was increased when this compound was formulated with low concentrations of benzalkonium chloride or ethyl alcohol, lactic acid, sodium benzoate, cationic polymer, and salicylic acid. This study demonstrates that the use of hydrogen peroxide with other antimicrobial products, in adequate concentrations, had bactericidal efficacy in Gram-positive and Gram-negative bacteria on stainless steel surfaces, enabling to reduce the effective concentration of hydrogen peroxide. In the same way, the use of hydrogen peroxide-based disinfectants could reduce the concentrations of traditional disinfectants as quaternary ammonium compounds and therefore a reduction of their chemical residues in the environment after being used. The study of the bactericidal properties of environmentally nontoxic disinfectants such as hydrogen peroxide, sole or in formulations with other disinfectants against Gram-positive and Gram-negative bacteria can enhance the efficacy of various commonly used disinfectant formulations with the hygiene benefits that it entails. Also, the use of hydrogen peroxide formulations can reduce the concentration levels of products that generate environmental residues. © 2017 Institute of Food Technologists®.

  11. Seawater usable for production and consumption of hydrogen peroxide as a solar fuel.

    Science.gov (United States)

    Mase, Kentaro; Yoneda, Masaki; Yamada, Yusuke; Fukuzumi, Shunichi

    2016-05-04

    Hydrogen peroxide (H2O2) in water has been proposed as a promising solar fuel instead of gaseous hydrogen because of advantages on easy storage and high energy density, being used as a fuel of a one-compartment H2O2 fuel cell for producing electricity on demand with emitting only dioxygen (O2) and water. It is highly desired to utilize the most earth-abundant seawater instead of precious pure water for the practical use of H2O2 as a solar fuel. Here we have achieved efficient photocatalytic production of H2O2 from the most earth-abundant seawater instead of precious pure water and O2 in a two-compartment photoelectrochemical cell using WO3 as a photocatalyst for water oxidation and a cobalt complex supported on a glassy-carbon substrate for the selective two-electron reduction of O2. The concentration of H2O2 produced in seawater reached 48 mM, which was high enough to operate an H2O2 fuel cell.

  12. Effects of brown coal treatment with hydrogen peroxide on brown coal wax yield

    Energy Technology Data Exchange (ETDEWEB)

    Bazarova, O.V.; Shevchenko, A.G.; Ruban, I.V.; Ksenofontov, V.G.; Turovskii, N.A. (Institut Fiziko-Organicheskoi Khimii i Uglekhimii AN UkrSSR (USSR))

    1990-09-01

    Studies preliminary treatment of brown coal with 30% hydrogen peroxide. Experiments employed 0.1-0.2 mm fractions of brown coal and were carried out at ambient temperature for 30 min with a coal:oxidizer ratio of 1:6. Sample demineralization met the requirements of ISO 602. Spectral resonance methods were employed to find that the oxidation processes of brown coal and of anthracite are similar; two spectra are presented. Coal extraction employed petroleum ether. Pre-treatment increased the wax yield from 4.3% to 10.5% in terms of coal organic mass. Wax elemental compositions are presented. Six IR spectra are shown and discussed: of initial coal wax, of pre-treated coal wax, of initial coal, of pre-treated coal, of initial coal residue (after its extraction) and of pre-treated coal residue. The 1,020 cm{sup -1} band was observed to suggest the formation of phenol structures during oxidation. The 1,610 cm{sup -1} band of aromatic structures with carboxylic groups increased its intensity. The wax hydrogen content doubled and H/O increased by 1/3-1/4. 12 refs.

  13. Dissection of the binding of hydrogen peroxide to trypsin using spectroscopic methods and molecular modeling

    Science.gov (United States)

    Song, Wei; Yu, Zehua; Hu, Xinxin; Liu, Rutao

    2015-02-01

    Studies on the effects of environmental pollutants to protein in vitro has become a global attention. Hydrogen peroxide (H2O2) is used as an effective food preservative and bleacher in industrial production. The toxicity of H2O2 to trypsin was investigated by multiple spectroscopic techniques and the molecular docking method at the molecular level. The intrinsic fluorescence of trypsin was proved to be quenched in a static process based on the results of fluorescence lifetime experiment. Hydrogen bonds interaction and van der Waals forces were the main force to generate the trypsin-H2O2 complex on account of the negative ΔH0 and ΔS0. The binding of H2O2 changed the conformational structures and internal microenvironment of trypsin illustrated by UV-vis absorption, fluorescence, synchronous fluorescence, three-dimensional (3D) fluorescence and circular dichroism (CD) results. However, the binding site was far away from the active site of trypsin and the trypsin activity was only slightly affected by H2O2, which was further explained by molecular docking investigations.

  14. Lipid Peroxide-Derived Short-Chain Carbonyls Mediate Hydrogen Peroxide-Induced and Salt-Induced Programmed Cell Death in Plants1[OPEN

    Science.gov (United States)

    Biswas, Md. Sanaullah; Mano, Jun’ichi

    2015-01-01

    Lipid peroxide-derived toxic carbonyl compounds (oxylipin carbonyls), produced downstream of reactive oxygen species (ROS), were recently revealed to mediate abiotic stress-induced damage of plants. Here, we investigated how oxylipin carbonyls cause cell death. When tobacco (Nicotiana tabacum) Bright Yellow-2 (BY-2) cells were exposed to hydrogen peroxide, several species of short-chain oxylipin carbonyls [i.e. 4-hydroxy-(E)-2-nonenal and acrolein] accumulated and the cells underwent programmed cell death (PCD), as judged based on DNA fragmentation, an increase in terminal deoxynucleotidyl transferase dUTP nick end labeling-positive nuclei, and cytoplasm retraction. These oxylipin carbonyls caused PCD in BY-2 cells and roots of tobacco and Arabidopsis (Arabidopsis thaliana). To test the possibility that oxylipin carbonyls mediate an oxidative signal to cause PCD, we performed pharmacological and genetic experiments. Carnosine and hydralazine, having distinct chemistry for scavenging carbonyls, significantly suppressed the increase in oxylipin carbonyls and blocked PCD in BY-2 cells and Arabidopsis roots, but they did not affect the levels of ROS and lipid peroxides. A transgenic tobacco line that overproduces 2-alkenal reductase, an Arabidopsis enzyme to detoxify α,β-unsaturated carbonyls, suffered less PCD in root epidermis after hydrogen peroxide or salt treatment than did the wild type, whereas the ROS level increases due to the stress treatments were not different between the lines. From these results, we conclude that oxylipin carbonyls are involved in the PCD process in oxidatively stressed cells. Our comparison of the ability of distinct carbonyls to induce PCD in BY-2 cells revealed that acrolein and 4-hydroxy-(E)-2-nonenal are the most potent carbonyls. The physiological relevance and possible mechanisms of the carbonyl-induced PCD are discussed. PMID:26025050

  15. Hydrogen peroxide induces activation of insulin signaling pathway via AMP-dependent kinase in podocytes

    Energy Technology Data Exchange (ETDEWEB)

    Piwkowska, Agnieszka, E-mail: apiwkowska@cmdik.pan.pl [Mossakowski Medical Research Centre, Polish Academy of Sciences, Laboratory of Molecular and Cellular Nephrology, Gdansk (Poland); Rogacka, Dorota; Angielski, Stefan [Mossakowski Medical Research Centre, Polish Academy of Sciences, Laboratory of Molecular and Cellular Nephrology, Gdansk (Poland); Jankowski, Maciej [Mossakowski Medical Research Centre, Polish Academy of Sciences, Laboratory of Molecular and Cellular Nephrology, Gdansk (Poland); Medical University of Gdansk, Department of Therapy Monitoring and Pharmacogenetics (Poland)

    2012-11-09

    Highlights: Black-Right-Pointing-Pointer H{sub 2}O{sub 2} activates the insulin signaling pathway and glucose uptake in podocytes. Black-Right-Pointing-Pointer H{sub 2}O{sub 2} induces time-dependent changes in AMPK phosphorylation. Black-Right-Pointing-Pointer H{sub 2}O{sub 2} enhances insulin signaling pathways via AMPK activation. Black-Right-Pointing-Pointer H{sub 2}O{sub 2} stimulation of glucose uptake is AMPK-dependent. -- Abstract: Podocytes are cells that form the glomerular filtration barrier in the kidney. Insulin signaling in podocytes is critical for normal kidney function. Insulin signaling is regulated by oxidative stress and intracellular energy levels. We cultured rat podocytes to investigate the effects of hydrogen peroxide (H{sub 2}O{sub 2}) on the phosphorylation of proximal and distal elements of insulin signaling. We also investigated H{sub 2}O{sub 2}-induced intracellular changes in the distribution of protein kinase B (Akt). Western blots showed that H{sub 2}O{sub 2} (100 {mu}M) induced rapid, transient phosphorylation of the insulin receptor (IR), the IR substrate-1 (IRS1), and Akt with peak activities at 5 min ({Delta} 183%, P < 0.05), 3 min ({Delta} 414%, P < 0.05), and 10 min ({Delta} 35%, P < 0.05), respectively. Immunostaining cells with an Akt-specific antibody showed increased intensity at the plasma membrane after treatment with H{sub 2}O{sub 2}>. Furthermore, H{sub 2}O{sub 2} inhibited phosphorylation of the phosphatase and tensin homologue (PTEN; peak activity at 10 min; {Delta} -32%, P < 0.05) and stimulated phosphorylation of the AMP-dependent kinase alpha subunit (AMPK{alpha}; 78% at 3 min and 244% at 10 min). The stimulation of AMPK was abolished with an AMPK inhibitor, Compound C (100 {mu}M, 2 h). Moreover, Compound C significantly reduced the effect of H{sub 2}O{sub 2} on IR phosphorylation by about 40% (from 2.07 {+-} 0.28 to 1.28 {+-} 0.12, P < 0.05). In addition, H{sub 2}O{sub 2} increased glucose uptake in podocytes

  16. The Effects of Hydrogen Peroxide Solution and Tetracycline Ointment in Healing of Traumatic Facial Wounds: A Comparative Study

    Directory of Open Access Journals (Sweden)

    B Barati

    2012-05-01

    Full Text Available

    Background and objectives

     Wound repair after a surgical operation or traumatic injuries is a coordinated process, which is highly dependent to the pre- and post-operative or traumatic care. There is no consensus on the best wound care method and application of topical therapeutic agents including diluted oxygen peroxide solution and antibiotics. This study is aimed to compare the healing effects of oxygen peroxide and tetracycline ointment in management of traumatic facial injuries.

     

    Methods

     76 patients divided into two groups were entered into this randomized clinical trial. All patients sustained facial injuries requiring primary repair. The first group received 2% topical oxygen peroxide solution for 5 days, and the second group received sterile 1% tetracycline topical ointment for 5days. At the end of the fourth day, wound healing status was assessed with a chart designed for this purpose.

     

    Results

     No statistically significant difference was observed between the tetracycline and hydrogen peroxide groups in regards to the distance of wound margins, erythema and dehiscence.

     

    Conclusion

     According to our results, there is no difference in the effects of hydrogen peroxide solution or tetracycline ointment on the healing of traumatic facial wounds.

     

  17. Simultaneous Removal of MTBE and Benzene from Contaminated Groundwater Using Ultraviolet-Based Ozone and Hydrogen Peroxide

    Directory of Open Access Journals (Sweden)

    Bassam S. Tawabini

    2014-01-01

    Full Text Available Efficiency of ultraviolet-ozone (UV/O3 and ultraviolet-hydrogen peroxide (UV/H2O2 processes was investigated for simultaneous removal of methyl tertiary butyl ether (MTBE and benzene from contaminated ground water. The photoreactor employed housed 15-watt low pressure (LP and 150-watt medium pressure (MP mercury UV lamps. Oxidation of contaminants was studied at two different levels of ozone and hydrogen peroxide. Brackish groundwater samples were spiked with MTBE and benzene up to a concentration of 500 μg L−1. Removal potential was evaluated at different parameters such as UV type and intensity and peroxide and ozone dosages, as well as contact time. Results indicated that no removal of the contaminants was attained when treated with hydrogen peroxide or ozone alone. However, about 50% and 30% removal of MTBE were achieved in 30 minutes when irradiated with MP-UV and LP-UV lamps, respectively. On the other hand, UV/H2O2 process was found to be superior in removal of MTBE (90% in 10 min. and benzene (95% in 5 min. compared to UV/O3 process. Furthermore, removal of benzene was comparatively easier than MTBE in both approaches. It is hence concluded that higher UV intensities and elevated doses of H2O2 accelerate simultaneous removal of MTBE and benzene from water.

  18. Exposure of mice to chronic hypoxia attenuates pulmonary arterial contractile responses to acute hypoxia by increases in extracellular hydrogen peroxide.

    Science.gov (United States)

    Patel, Dhara; Alhawaj, Raed; Wolin, Michael S

    2014-08-15

    Exposing mice to a chronic hypoxic treatment (10% oxygen, 21 days) that promotes pulmonary hypertension was observed to attenuate the pulmonary vasoconstriction response to acute hypoxia (HPV) both in vivo and in isolated pulmonary arteries. Since catalase restored the HPV response in isolated arteries, it appeared to be attenuated by extracellular hydrogen peroxide. Chronic hypoxia promoted the detection of elevated lung superoxide, extracellular peroxide, extracellular SOD expression, and protein kinase G (PKG) activation [based on PKG dimerization and vasodilator-stimulated phosphoprotein (VASP) phosphorylation], suggesting increased generation of extracellular peroxide and PKG activation may contribute to the suppression of HPV. Aorta from mice exposed to 21 days of hypoxia also showed evidence for extracellular hydrogen peroxide, suppressing the relaxation response to acute hypoxia. Peroxide appeared to partially suppress contractions to phenylephrine used in the study of in vitro hypoxic responses. Treatment of mice with the heme precursor δ-aminolevulinic acid (ALA; 50 mg·kg(-1)·day(-1)) during exposure to chronic hypoxia was examined as a pulmonary hypertension therapy because it could potentially activate beneficial cGMP-mediated effects through promoting a prolonged protoporphyrin IX (PpIX)-elicited activation of soluble guanylate cyclase. ALA attenuated pulmonary hypertension, increases in both superoxide and peroxide, and the suppression of in vitro and in vivo HPV responses. ALA generated prolonged detectible increases in PpIX and PKG-associated phosphorylation of VASP, suggesting PKG activation may contribute to suppression of pulmonary hypertension and prevention of alterations in extracellular peroxide that appear to be attenuating HPV responses caused by chronic hypoxia. Copyright © 2014 the American Physiological Society.

  19. NMR-based untargeted metabolomic study of hydrogen peroxide-induced development and diapause termination in brine shrimp.

    Science.gov (United States)

    Hong, Ming-Chang; Ding, Shangwu; Lin, Cheng-Chi; Chu, Tah-Wei; Chiu, Kuo-Hsun

    2017-12-01

    Artemia diapause has been extensively studied in embryonic biology for a long time. It has been demonstrated that hydrogen peroxide (H2O2) can increase the hatching rate in the development and diapause termination of Artemia cysts. This study used an untargeted 1H NMR-based metabolomic approach to explore the physiological regulation of H2O2 in initiating the development and terminating the diapause of Artemia cysts. This experiment was divided into two parts. In the first part, we analyzed three groups with or without H2O2 as control-0h, control-5h and H2O2 (180μM)-5h; in the second part, after 7-d incubation, the non-hatching cysts were treated with different H2O2 concentrations as low as 180μM and as high 1800μM. The results showed that arginine and proline metabolism were up-regulated after 5h, and H2O2 up-regulated valine, leucine and isoleucine biosynthesis in the development of cysts. In the second part, low H2O2 (180μM) showed alanine, aspartate and glutamate metabolism, but high H2O2 (1800μM) also up-regulated arginine and proline metabolism, as in the control group without H2O2 stimulus. These results suggest that enough H2O2 can catalyze cell transcription and translation in Artemia cysts, and it improves the cell growth rate, thus allowing embryo cells to grow again. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Microscale packed bed reactor for controlled hydrogen peroxide decomposition as a fuel cell oxidant aboard unmanned undersea vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Lennon, E.; Ocampo, M.; Besser, R.S. [Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, NJ 07030 (United States); Burke, A.A. [Naval Undersea Warfare Center, Newport, RI 02841 (United States)

    2010-01-01

    The multiphase catalytic decomposition of hydrogen peroxide into water and oxygen is notoriously susceptible to thermal runaway (heat of reaction: -98 kJ mol{sup -1}). The high surface area to volume ratio (S/V) in a microscale packed bed (MPB) reactor (radius 0.5 mm) was investigated for reducing the risk of thermal runaway during hydrogen peroxide decomposition to oxygen intended as a fuel cell oxidant aboard an unmanned undersea vehicle (UUV). A microscale reactor channel with a S/V of {proportional_to}2 x 10{sup 3} m{sup 2} m{sup -3} simulated under convective cooling generated a significant heat rise (T rise {proportional_to} 100 K), whereas a microreactor with a higher S/V ({proportional_to}200 x 10{sup 3} m{sup 2} m{sup -3}) achieved thermal control (T rise < 10 K) over the simulated reaction zone. Although thermal management was successfully accomplished using the higher S/V, experimental conversions of hydrogen peroxide to oxygen (5-18%) measured from the outlet were lower than simulated conversions (38-63%). Simulation assumptions, such as homogeneously dispersed flow and perfect catalyst interaction among other factors, contributed to the discrepancies between the simulated and experimental degrees of peroxide conversion to oxygen. Even though thermal control of the MPB was achieved, this work indicates that mass transfer limitations are a factor in the MPB reactor during a multiphase reaction, like decomposition of hydrogen peroxide to oxygen and water, and suggests means to overcome them even on the microscale level. (author)

  1. Reductimetric determination of peroxydisulphate, hydrogen peroxide, sodium perborate, nitrate and nitrite in concentrated phosphoric acid medium with iron(II).

    Science.gov (United States)

    Murty, N K; Satyanarayana, V; Rao, Y F

    1977-12-01

    A direct reductimetric method for the determination of peroxydisulphate, hydrogen peroxide, sodium perborate, nitrate and nitrite in fairly concentrated phosphoric acid medium with iron(II) has been developed, with both potentiometric and visual end-point detection. Cacotheline, Methylene Blue, thionine, Azure A, Azure B, Azure C, Toluidine Blue, new Methylene Blue, ferroin, N-phenylanthranilic acid, p-ethoxychrysoidine and barium diphenylaminesulphonate are used as indicators. The method is useful in the analysis of binary mixtures of peroxydisulphate and peroxide or perborate and in the estimation of the nitrate content of fertilizers.

  2. 7-Nitro-4-(phenylthio)benzofurazan is a potent generator of superoxide and hydrogen peroxide.

    Science.gov (United States)

    Patridge, Eric V; Eriksson, Emma S E; Penketh, Philip G; Baumann, Raymond P; Zhu, Rui; Shyam, Krishnamurthy; Eriksson, Leif A; Sartorelli, Alan C

    2012-10-01

    Here, we report on 7-nitro-4-(phenylthio)benzofurazan (NBF-SPh), the most potent derivative among a set of patented anticancer 7-nitrobenzofurazans (NBFs), which have been suggested to function by perturbing protein-protein interactions. We demonstrate that NBF-SPh participates in toxic redox-cycling, rapidly generating reactive oxygen species (ROS) in the presence of molecular oxygen, and this is the first report to detail ROS production for any of the anticancer NBFs. Oxygraph studies showed that NBF-SPh consumes molecular oxygen at a substantial rate, rivaling even plumbagin, menadione, and juglone. Biochemical and enzymatic assays identified superoxide and hydrogen peroxide as products of its redox-cycling activity, and the rapid rate of ROS production appears to be sufficient to account for some of the toxicity of NBF-SPh (LC(50) = 12.1 μM), possibly explaining why tumor cells exhibit a sharp threshold for tolerating the compound. In cell cultures, lipid peroxidation was enhanced after treatment with NBF-SPh, as measured by 2-thiobarbituric acid-reactive substances, indicating a significant accumulation of ROS. Thioglycerol rescued cell death and increased survival by 15-fold to 20-fold, but pyruvate and uric acid were ineffective protectants. We also observed that the redox-cycling activity of NBF-SPh became exhausted after an average of approximately 19 cycles per NBF-SPh molecule. Electrochemical and computational analyses suggest that partial reduction of NBF-SPh enhances electrophilicity, which appears to encourage scavenging activity and contribute to electrophilic toxicity.

  3. Hydrogen peroxide is involved in the sclerotial differentiation of filamentous phytopathogenic fungi.

    Science.gov (United States)

    Papapostolou, I; Georgiou, C D

    2010-12-01

    The purpose of this study was to investigate the role of H(2) O(2) and the related oxidative stress markers catalase (CAT) and lipid peroxidation in the sclerotial differentiation of the phytopathogenic filamentous fungi Sclerotium rolfsii, Sclerotinia minor, Sclerotinia sclerotiorum and Rhizoctonia solani. Using the H(2) O(2) -specific scopoletin fluorometric assay and the CAT-dependent H(2) O(2) consumption assays, it was found that the production rate of intra/extracellular H(2) O(2) and CAT levels in the sclerotiogenic fungi were significantly higher and lower, respectively, than those of their nondifferentiating counterpart strains. They peaked in the transition between the undifferentiated and the differentiated state of the sclerotiogenic strains, suggesting both a cell proliferative and differentiative role. In addition, the indirect indicator of oxidative stress, lipid peroxidation, was substantially decreased in the nondifferentiating strains. These findings suggest that the differentiative role of H(2) O(2) is expressed via induction of higher oxidative stress in the sclerotiogenic filamentous phytopathogenic fungi. This study shows that the direct marker of oxidative stress H(2) O(2) is involved in the sclerotial differentiation of the phytopathogenic filamentous fungi S. rolfsii, S. minor, S. sclerotiorum and R. solani, which could have potential biotechnological implications in terms of developing antifungal strategies by regulating intracellular H(2) O(2) levels. © 2010 The Authors. Journal of Applied Microbiology © 2010 The Society for Applied Microbiology.

  4. Effects of Hydrogen Peroxide on Dental Unit Biofilms and Treatment Water Contamination

    Science.gov (United States)

    Lin, Shih-Ming; Svoboda, Kathy K.H.; Giletto, Anthony; Seibert, Jeff; Puttaiah, Raghunath

    2011-01-01

    Objectives: To study effects of various concentrations of hydrogen peroxide on mature waterline biofilms and in controlling planktonic (free-floating) organisms in simulated dental treatment water systems; and to study in vitro the effects of 2%, 3%, and 7% hydrogen peroxide on the removal of mature biofilms and inorganic compounds in dental waterlines. Methods: Four units of an automated dental unit water system simulation device was used for 12 weeks. All units were initially cleaned to control biofilms and inorganic deposits. H2O2 at concentrations of 1%, 2%, 3% was used weekly for periodic cleaning in three treatment group units (units 1, 2 & 3), with 0.05%, 0.15% and 0.25% H2O2 in municipal water used as irrigant respectively. The control unit (unit 4) did not have weekly cleanings and used municipal water as irrigant. Laser Scanning Confocal Microscopy and Scanning Electron Microscopy were used to study deposits on lines, and weekly heterotrophic plate counts done to study effluent water contamination. A 24 hour in vitro challenge test with 7%, 3% and 2% H2O2 on mature biofilms was conducted using harvested waterlines to study biofilm and inorganic deposit removal. Results: Heterotrophic plate counts of effluent water showed that the control unit reached contamination levels in excess of 400,000 CFU/mL while all treatment units showed contamination levels biofilm and inorganic deposit control in this short 12 week study. The in vitro challenge test showed although there was biofilm control, there was no eradication even when 7% H2O2 was used for 24 hours. Conclusions: 2% H2O2 used as a periodic cleaner, and diluted to 0.05% in municipal water for irrigation was beneficial in controlling biofilm and planktonic contamination in dental unit water systems. However, to remove well established biofilms, it may take more than 2 months when initial and multiple periodic cleanings are performed using H2O2. PMID:21228956

  5. Structural characterization of alkaline hydrogen peroxide pretreated grasses exhibiting diverse lignin phenotypes

    Directory of Open Access Journals (Sweden)

    Li Muyang

    2012-06-01

    Full Text Available Abstract Background For cellulosic biofuels processes, suitable characterization of the lignin remaining within the cell wall and correlation of quantified properties of lignin to cell wall polysaccharide enzymatic deconstruction is underrepresented in the literature. This is particularly true for grasses which represent a number of promising bioenergy feedstocks where quantification of grass lignins is particularly problematic due to the high fraction of p-hydroxycinnamates. The main focus of this work is to use grasses with a diverse range of lignin properties, and applying multiple lignin characterization platforms, attempt to correlate the differences in these lignin properties to the susceptibility to alkaline hydrogen peroxide (AHP pretreatment and subsequent enzymatic deconstruction. Results We were able to determine that the enzymatic hydrolysis of cellulose to to glucose (i.e. digestibility of four grasses with relatively diverse lignin phenotypes could be correlated to total lignin content and the content of p-hydroxycinnamates, while S/G ratios did not appear to contribute to the enzymatic digestibility or delignification. The lignins of the brown midrib corn stovers tested were significantly more condensed than a typical commercial corn stover and a significant finding was that pretreatment with alkaline hydrogen peroxide increases the fraction of lignins involved in condensed linkages from 88–95% to ~99% for all the corn stovers tested, which is much more than has been reported in the literature for other pretreatments. This indicates significant scission of β-O-4 bonds by pretreatment and/or induction of lignin condensation reactions. The S/G ratios in grasses determined by analytical pyrolysis are significantly lower than values obtained using either thioacidolysis or 2DHSQC NMR due to presumed interference by ferulates. Conclusions It was found that grass cell wall polysaccharide hydrolysis by cellulolytic enzymes for grasses

  6. Modulation of Na+/K+ ATPase Activity by Hydrogen Peroxide Generated through Heme in L. amazonensis.

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    Nathália Rocco-Machado

    Full Text Available Leishmania amazonensis is a protozoan parasite that occurs in many areas of Brazil and causes skin lesions. Using this parasite, our group showed the activation of Na+/K+ ATPase through a signaling cascade that involves the presence of heme and protein kinase C (PKC activity. Heme is an important biomolecule that has pro-oxidant activity and signaling capacity. Reactive oxygen species (ROS can act as second messengers, which are required in various signaling cascades. Our goal in this work is to investigate the role of hydrogen peroxide (H2O2 generated in the presence of heme in the Na+/K+ ATPase activity of L. amazonensis. Our results show that increasing concentrations of heme stimulates the production of H2O2 in a dose-dependent manner until a concentration of 2.5 μM heme. To confirm that the effect of heme on the Na+/K+ ATPase is through the generation of H2O2, we measured enzyme activity using increasing concentrations of H2O2 and, as expected, the activity increased in a dose-dependent manner until a concentration of 0.1 μM H2O2. To investigate the role of PKC in this signaling pathway, we observed the production of H2O2 in the presence of its activator phorbol 12-myristate 13-acetate (PMA and its inhibitor calphostin C. Both showed no effect on the generation of H2O2. Furthermore, we found that PKC activity is increased in the presence of H2O2, and that in the presence of calphostin C, H2O2 is unable to activate the Na+/K+ ATPase. 100 μM of Mito-TEMPO was capable of abolishing the stimulatory effect of heme on Na+/K+ ATPase activity, indicating that mitochondria might be the source of the hydrogen peroxide production induced by heme. The modulation of L. amazonensis Na+/K+ ATPase by H2O2 opens new possibilities for understanding the signaling pathways of this parasite.

  7. Inactivation of duck hepatitis B virus by a hydrogen peroxide gas plasma sterilization system: laboratory and 'in use' testing.

    Science.gov (United States)

    Vickery, K; Deva, A K; Zou, J; Kumaradeva, P; Bissett, L; Cossart, Y E

    1999-04-01

    Human hepatitis B virus (HBV) is an important cause of nosocomial infections and can be transmitted by contaminated instruments. However, tests of the efficacy of sterilization of materials and equipment contaminated by HBV are difficult to perform because the virus cannot be cultured in the laboratory. In this study, we aimed to evaluate the capability of a low temperature, hydrogen peroxide gas plasma sterilizer (Sterrad, Advanced Sterilization Products, Irvine California,) to inactivate duck hepatitis B virus (DHBV). In laboratory efficacy studies using DHBV dried on to glass filter carriers and exposed to one-half of the hydrogen peroxide gas plasma sterilization process, there was a 10(7) or greater decrease in the viral titer, with no infectivity detected on the carriers after treatment. In-use studies were performed using a laparoscope that was experimentally contaminated with DHBV to mimic the possible transmission of infection between successive patients. Following exposure to the hydrogen peroxide gas plasma sterilization process no transmission of DHBV infection from the laparoscope occurred despite obvious visual soiling with blood (N = 8) while the transmission rate for the unprocessed laparoscope (positive control) was 100% (26/26), and that for instruments after a water wash was 63% (7/11). In conclusion the hydrogen gas plasma sterilization process completely inactivates DHBV a representative of the hepadna group of viruses.

  8. Urea Hydrogen Peroxide Reduces the Numbers of Lactobacilli, Nourishes Yeast, and Leaves No Residues in the Ethanol Fermentation

    Science.gov (United States)

    Narendranath, N. V.; Thomas, K. C.; Ingledew, W. M.

    2000-01-01

    Urea hydrogen peroxide (UHP) at a concentration of 30 to 32 mmol/liter reduced the numbers of five Lactobacillus spp. (Lactobacillus plantarum, L. paracasei, Lactobacillus sp. strain 3, L. rhamnosus, and L. fermentum) from ∼107 to ∼102 CFU/ml in a 2-h preincubation at 30°C of normal-gravity wheat mash at ∼21 g of dissolved solids per ml containing normal levels of suspended grain particles. Fermentation was completed 36 h after inoculation of Saccharomyces cerevisiae in the presence of UHP, even when wheat mash was deliberately contaminated (infected) with L. paracasei at ∼107 CFU/ml. There were no significant differences in the maximum ethanol produced between treatments when urea hydrogen peroxide was used to kill the bacteria and controls (in which no bacteria were added). However, the presence of L. paracasei at ∼107 CFU/ml without added agent resulted in a 5.84% reduction in the maximum ethanol produced compared to the control. The bactericidal activity of UHP is greatly affected by the presence of particulate matter. In fact, only 2 mmol of urea hydrogen peroxide per liter was required for disinfection when mashes had little or no particulate matter present. No significant differences were observed in the decomposition of hydrogen peroxide in normal-gravity wheat mash at 30°C whether the bactericidal agent was added as H2O2 or as urea hydrogen peroxide. NADH peroxidase activity (involved in degrading H2O2) increased significantly (P = 0.05) in the presence of 0.75 mM hydrogen peroxide (sublethal level) in all five strains of lactobacilli tested but did not persist in cells regrown in the absence of H2O2. H2O2-resistant mutants were not expected or found when lethal levels of H2O2 or UHP were used. Contaminating lactobacilli can be effectively managed by UHP, a compound which when used at ca. 30 mmol/liter happens to provide near-optimum levels of assimilable nitrogen and oxygen that aid in vigorous fermentation performance by yeast. PMID:11010858

  9. Chemical approaches to discovery and study of sources and targets of hydrogen peroxide redox signaling through NADPH oxidase proteins.

    Science.gov (United States)

    Brewer, Thomas F; Garcia, Francisco J; Onak, Carl S; Carroll, Kate S; Chang, Christopher J

    2015-01-01

    Hydrogen peroxide (H2O2) is a prime member of the reactive oxygen species (ROS) family of molecules produced during normal cell function and in response to various stimuli, but if left unchecked, it can inflict oxidative damage on all types of biological macromolecules and lead to cell death. In this context, a major source of H2O2 for redox signaling purposes is the NADPH oxidase (Nox) family of enzymes, which were classically studied for their roles in phagocytic immune response but have now been found to exist in virtually all mammalian cell types in various isoforms with distinct tissue and subcellular localizations. Downstream of this tightly regulated ROS generation, site-specific, reversible covalent modification of proteins, particularly oxidation of cysteine thiols to sulfenic acids, represents a prominent posttranslational modification akin to phosphorylation as an emerging molecular mechanism for transforming an oxidant signal into a dynamic biological response. We review two complementary types of chemical tools that enable (a) specific detection of H2O2 generated at its sources and (b) mapping of sulfenic acid posttranslational modification targets that mediate its signaling functions, which can be used to study this important chemical signal in biological systems.

  10. Resveratrol protects C6 astrocyte cell line against hydrogen peroxide-induced oxidative stress through heme oxygenase 1.

    Directory of Open Access Journals (Sweden)

    André Quincozes-Santos

    Full Text Available Resveratrol, a polyphenol presents in grapes and wine, displays antioxidant and anti-inflammatory properties and cytoprotective effect in brain pathologies associated to oxidative stress and neurodegeneration. In previous work, we demonstrated that resveratrol exerts neuroglial modulation, improving glial functions, mainly related to glutamate metabolism. Astrocytes are a major class of glial cells and regulate neurotransmitter systems, synaptic processing, energy metabolism and defense against oxidative stress. This study sought to determine the protective effect of resveratrol against hydrogen peroxide (H2O2-induced cytotoxicity in C6 astrocyte cell line, an astrocytic lineage, on neurochemical parameters and their cellular and biochemical mechanisms. H2O2 exposure increased oxidative-nitrosative stress, iNOS expression, cytokine proinflammatory release (TNFα levels and mitochondrial membrane potential dysfunction and decreased antioxidant defenses, such as SOD, CAT and creatine kinase activity. Resveratrol strongly prevented C6 cells from H2O2-induced toxicity by modulating glial, oxidative and inflammatory responses. Resveratrol per se increased heme oxygenase 1 (HO1 expression and extracellular GSH content. In addition, HO1 signaling pathway is involved in the protective effect of resveratrol against H2O2-induced oxidative damage in astroglial cells. Taken together, these results show that resveratrol represents an important mechanism for protection of glial cells against oxidative stress.

  11. The sigma-1 receptor-zinc finger protein 179 pathway protects against hydrogen peroxide-induced cell injury.

    Science.gov (United States)

    Su, Tzu-Chieh; Lin, Shu-Hui; Lee, Pin-Tse; Yeh, Shiu-Hwa; Hsieh, Tsung-Hsun; Chou, Szu-Yi; Su, Tsung-Ping; Hung, Jan-Jong; Chang, Wen-Chang; Lee, Yi-Chao; Chuang, Jian-Ying

    2016-06-01

    The accumulation of reactive oxygen species (ROS) have implicated the pathogenesis of several human diseases including neurodegenerative disorders, stroke, and traumatic brain injury, hence protecting neurons against ROS is very important. In this study, we focused on sigma-1 receptor (Sig-1R), a chaperone at endoplasmic reticulum, and investigated its protective functions. Using hydrogen peroxide (H2O2)-induced ROS accumulation model, we verified that apoptosis-signaling pathways were elicited by H2O2 treatment. However, the Sig-1R agonists, dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEAS), reduced the activation of apoptotic pathways significantly. By performing protein-protein interaction assays and shRNA knockdown of Sig-1R, we identified the brain Zinc finger protein 179 (Znf179) as a downstream target of Sig-1R regulation. The neuroprotective effect of Znf179 overexpression was similar to that of DHEAS treatment, and likely mediated by affecting the levels of antioxidant enzymes. We also quantified the levels of peroxiredoxin 3 (Prx3) and superoxide dismutase 2 (SOD2) in the hippocampi of wild-type and Znf179 knockout mice, and found both enzymes to be reduced in the knockout versus the wild-type mice. In summary, these results reveal that Znf179 plays a novel role in neuroprotection, and Sig-1R agonists may be therapeutic candidates to prevent ROS-induced damage in neurodegenerative and neurotraumatic diseases. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Re-evaluation of melanin bleaching using warm diluted hydrogen peroxide for histopathological analysis.

    Science.gov (United States)

    Momose, Masanobu; Ota, Hiroyoshi; Hayama, Masayoshi

    2011-06-01

    Excessive amounts of melanin pigments may hamper histopathological assessments of melanocytic lesions by obscuring cellular morphology and hindering antibody-antigen interactions. To determine the optimal melanin-bleaching conditions for histopathological examination, heavily pigmented melanomas were treated with warm hydrogen peroxide (H2O2) diluted with various diluents (1% disodium hydrogen phosphate 12H2O (Na2 HPO4); phosphate buffer 0.05 M, pH 7.4 (PB); and PBS 0.05 M, pH 7.4) at varying temperatures (50°C, 55°C, and 60°C) and for varying incubation times (0.5, 1, 2, and 3 h). The effect of the sequential order of antigen retrieval and bleaching on preserving tissue morphology was then evaluated. Additionally, the effect of melanin bleaching using warm diluted H2O2 on the antigenicity of melanoma-related markers (HMB-45, MART-1, and S-100) and other markers used for histopathology was examined in amelanotic melanomas and tonsil tissue. Optimal and complete bleaching was achieved using warm 3% H2O2 in PB treatment at 55°C for 2 h following antigen retrieval with microwaving or digestion with trypsin. Under these conditions, the tissue morphology and antigenicity of various immunohistochemical markers were also well preserved. Bleaching with warm 3% H2O2 PB is a fast and efficient method of bleaching melanin pigments and performing immunohistochemical examination in heavily melanin-pigmented lesions. © 2011 The Authors. Pathology International © 2011 Japanese Society of Pathology and Blackwell Publishing Asia Pty Ltd.

  13. The effect of hydrogen peroxide concentration on metal ion release from dental casting alloys.

    Science.gov (United States)

    Al-Salehi, S K; Hatton, P V; Johnson, A; Cox, A G; McLeod, C

    2008-04-01

    There are concerns that tooth bleaching agents may adversely affect dental materials. The aim of this study was to test the hypothesis that increasing concentrations of hydrogen peroxide (HP) are more effective than water at increasing metal ion release from two typical dental casting alloys during bleaching. Discs (n = 28 for each alloy) were prepared by casting and heat treated to simulate a typical porcelain-firing cycle. Discs (n = 7) of each alloy were immersed in either 0%, 3%, 10% or 30% (w/v) HP solutions for 24 h at 37 degrees C. Samples were taken for metal ion release determination using inductively coupled plasma-mass spectrometry and the data analysed using a two-way anova followed by a one-way anova. The surface roughness of each disc was measured using a Talysurf contact profilometer before and after bleaching and the data analysed using a paired t-test. With the exception of gold, the differences in metal ion concentration after treatment with 0% (control) and each of 3%, 10% and 30% HP (w/v) were statistically significant (P 0.05) Exposure of the two dental casting alloys to HP solutions increased metal ion release of all the elements except gold.

  14. Anthocyanin contributes more to hydrogen peroxide scavenging than other phenolics in apple peel.

    Science.gov (United States)

    Bi, Xiuli; Zhang, Jiangli; Chen, Changsheng; Zhang, Di; Li, Pengmin; Ma, Fengwang

    2014-01-01

    The phenolic compounds in apple peel extracts were quantified in the presence of hydrogen peroxide (H2O2) to identify which phenolic compound contributed more to H2O2 scavenging. The results showed that the phenolics extracted from 'Golden Delicious' apple peel had a strong ability for scavenging H2O2. After incubating with H2O2 for 30 min, cyanidin-3-galactoside concentrations in the phenolic extract decreased as H2O2 concentrations increased. In contrast, the concentrations of other phenolic compounds remained unchanged. Exogenous application of H2O2 enhanced the synthesis of phenolics, especially anthocyanin, in 'Golden Delicious' apple peel under sunlight. After incubating the peel extract of H2O2-treated apples in the dark for 30 min, the concentration of cyanidin-3-galactoside significantly decreased to a greater extent than that of other phenolic compounds. Based on these data, anthocyanin is more sensitive to H2O2 and contributes more to H2O2 scavenging than other phenolic compounds. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Response of Cytokines and Hydrogen Peroxide to Sporothrix schenckii Exoantigen in Systemic Experimental Infection.

    Science.gov (United States)

    Maia, Danielle Cardoso Geraldo; Gonçalves, Amanda Costa; Ferreira, Lucas Souza; Manente, Francine Alessandra; Portuondo, Deivys Leandro; Vellosa, José Carlos Rebuglio; Polesi, Marisa Campos; Batista-Duharte, Alexander; Carlos, Iracilda Zeppone

    2016-04-01

    The response of hydrogen peroxide (H2O2) and cytokines during an experimental sporotrichosis in male Swiss mice was assessed over a period of 10 weeks by monitoring macrophage activation challenged with exoantigen (ExoAg) from the fungus Sporothrix schenckii. The studied endpoints were: H2O2 production, fungal burden at spleen, apoptosis in peritoneal macrophages, and IL-1β, IL-6, IL-2, IL-10 production. During the two first weeks of infection was observed low burden of yeast in spleen and high response of H2O2, IL-2, and IL-1β. The weeks of highest fungal burden (fourth-sixth) coincided with major apoptosis in peritoneal macrophages, normal production of IL-6 and lower production of H2O2, IL-2, and IL-1β, suggesting a role for these three last in the early control of infection. On the other hand, IL-1β (but not IL-6) was recovered since the sixth week, suggesting a possible role in the late phase of infection, contributing to the fungal clearance in conjunction with the specific mechanisms. The IL-10 was elevated until the sixth, principally in the second week. These results evidences that ExoAg is involved in the host immune modulation, influencing the S. Schenckii virulence, and its role is related with the time of the infection in the model used.

  16. High performance supercapacitor and non-enzymatic hydrogen peroxide sensor based on tellurium nanoparticles

    Directory of Open Access Journals (Sweden)

    M. Manikandan

    2017-04-01

    Full Text Available Tellurium nanoparticles (Te Nps were synthesized by wet chemical method and characterized by XRD, Raman, FESEM, TEM, XPS, UV–Vis and FL. The Nps were coated on graphite foil and Glassy carbon electrode to prepare the electrodes for supercapacitor and biosensor applications. The supercapacitor performance is evaluated in 2 M KOH electrolyte by both Cyclic Voltammetry (CV and galvanostatic charge-discharge method. From charge-discharge method, Te Nps show a specific capacitance of 586 F/g at 2 mA/cm2 and 100 F/g at 30 mA/cm2 as well as an excellent cycle life (100% after 1000 cycles. In addition, the H2O2 sensor performance of Te Nps modified glassy carbon electrode is checked by CV and Chronoamperometry (CA in phosphate buffer solution (PBS. In the linear range of 0.67 to 8.04 μM of hydrogen peroxide (H2O2, Te NPs show a high sensitivity of 0.83 mA mM−1 cm−2 with a correlation coefficient of 0.995. The detection limit is 0.3 μM with a response time less than 5 s.

  17. Removal of Polyvinyl Alcohol Using Photoelectrochemical Oxidation Processes Based on Hydrogen Peroxide Electrogeneration

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    Kai-Yu Huang

    2013-01-01

    Full Text Available This study investigates the removal efficiency of PVA from aqueous solutions using UV irradiation in combination with the production of electrogenerated hydrogen peroxide (H2O2 at a polyacrylonitrile-based activated carbon fiber (ACF cathode. Three cathode materials (i.e., platinum, graphite, and ACF were fed with oxygen and used for the electrogeneration of H2O2. The amount of electrogenerated H2O2 produced using the ACF cathode was five times greater than that generated using the graphite cathode and nearly 24 times greater than that from platinum cathode. Several parameters were evaluated to characterize the H2O2 electrogeneration, such as current density, oxygen flow rate, solution pH, and the supporting electrolyte used. The optimum current density, oxygen flow rate, solution pH, and supporting electrolyte composition were found to be 10 mA cm−2, 500 cm3 min−1, pH 3, and Na2SO4, respectively. The PVA removal efficiencies were achieved under these conditions 3%, 16%, and 86% using UV, H2O2 electrogeneration, and UV/H2O2 electrogeneration, respectively. A UV light intensity of 0.6 mW cm−2 was found to produce optimal PVA removal efficiency in the present study. A simple kinetic model was proposed which confirmed pseudo-first-order reaction. Reaction rate constant (kap was found to depend on the UV light intensity.

  18. Hyperglycemia Promotes the Epithelial-Mesenchymal Transition of Pancreatic Cancer via Hydrogen Peroxide

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    Wei Li

    2016-01-01

    Full Text Available Diabetes mellitus (DM and pancreatic cancer are intimately related, as approximately 85% of patients diagnosed with pancreatic cancer have impaired glucose tolerance or even DM. Our previous studies have indicated that high glucose could promote the invasive and migratory abilities of pancreatic cancer cells. We therefore explored the underlying mechanism that hyperglycemia modulates the metastatic potential of pancreatic cancer. Our data showed that streptozotocin- (STZ- treated diabetic nude mice exhibit larger tumor size than that of the euglycemic mice. The number of nude mice that develop liver metastasis or ascites is much more in the STZ-treated group than that in the euglycemic group. Hyperglycemic mice contain a higher plasma H2O2-level than that from euglycemic mice. The injection of polyethylene glycol-conjugated catalase (PEG-CAT, an H2O2 scavenger, may reverse hyperglycemia-induced tumor metastasis. In addition, hyperglycemia could also modulate the expression of epithelial-mesenchymal transition- (EMT- related factors in pancreatic tumor tissues, as the E-cadherin level is decreased and the expression of mesenchymal markers N-cadherin and vimentin as well as transcription factor snail is strongly increased. The injection of PEG-CAT could also reverse hyperglycemia-induced EMT. These results suggest that the association between hyperglycemia and poor prognosis of pancreatic cancer can be attributed to the alterations of EMT through the production of hydrogen peroxide.

  19. Ratiometric fluorescent probe with AIE property for monitoring endogenous hydrogen peroxide in macrophages and cancer cells.

    Science.gov (United States)

    Liu, Yong; Nie, Jing; Niu, Jie; Meng, Fangfang; Lin, Weiying

    2017-08-04

    Hydrogen peroxide (H2O2) plays a key role in the progression of human illnesses, such as autoimmune and auto-inflammatory diseases, infectious diseases, diabetes, and cancer, etc. In this work, we have discribed a novel probe, TPE-TLE, which remarkably displayed AIE property and ratiometric fluorescence emission profiles in the presence of H2O2. This ratiometric fluorescent probe with AIE property exhibits outstanding features such as the well-resolved emission peaks, high sensitivity, high selectivity, low cytotoxicity, and good cell-membrane permeability. These excellent attributes enable us to demonstrate the ratiometric imaging of endogenously produced H2O2 in macrophages and cancer cells based on the novel ratiometric probe with AIE property for the first time. By comparing two kinds of cells, it is firstly found that cancer cells should contain much more endogenous H2O2 than macrophages. We expect that TPE-TLE will be useful fluorescent platform for the development of a variety of ratiometric fluorescent probes with AIE property to achieve unique biological applications.

  20. Ametryn degradation in the ultraviolet (UV) irradiation/hydrogen peroxide (H2O2) treatment.

    Science.gov (United States)

    Gao, Nai-Yun; Deng, Yang; Zhao, Dandan

    2009-05-30

    Ultraviolet (UV) irradiation (253.7nm) in the presence of hydrogen peroxide (H(2)O(2)) was used to decompose aqueous ametryn. The concentrations of ametryn were measured with time under various experiment conditions. The investigated factors included H(2)O(2) dosages, initial pH, initial ametryn concentrations, and a variety of inorganic anions. Results showed that ametryn degradation in UV/H(2)O(2) process was a pseudo-first-order reaction. Removal rates of ametryn were greatly affected by H(2)O(2) dosage and initial concentrations of ametryn, but appeared to be slightly influenced by initial pH. Furthermore, we investigated the effects of four anions (SO(4)(2-), Cl(-), HCO(3)(-), and CO(3)(2-)) on ametryn degradation by UV/H(2)O(2). The impact of SO(4)(2-) seemed to be insignificant; however, Cl(-), HCO(3)(-), and CO(3)(2-) considerably slowed down the degradation rate because they could strongly scavenge hydroxyl radicals (OH) produced during the UV/H(2)O(2) process. Finally, a preliminary cost analysis revealed that UV/H(2)O(2) process was more cost-effective than the UV alone in removal of ametryn from water.

  1. Hydrothermal synthesis of cobalt oxide porous nanoribbons anchored with reduced graphene oxide for hydrogen peroxide detection

    Science.gov (United States)

    Zhang, Xinmeng; Li, Kezhi; Li, Hejun; Lu, Jinhua; Fu, Qiangang; Zhang, Leilei

    2016-08-01

    A new Co3O4-reduced graphene oxide (Co3O4-rGO) nanostructure was successfully prepared by hydrothermal-synthesized Co3O4 porous nanoribbons with an approximate length of 6-17 μm, a width of 21-737 nm, and a thickness of 33-80 nm hybridizing with reduced graphene oxide. The electrochemical properties of the Co3O4-rGO-modified electrode were investigated by the cyclic voltammograms and amperometric current-time method. The modified electrode shows high electrochemical activity for the catalytic reduction and detection of H2O2 in alkaline medium. The nonenzymatic hydrogen peroxide sensor exhibits wide linear range of 1-18.5 mM ( R = 0.99439), high adsorption amount about 3.24 × 10-6 mol/cm2, and a low detection limit of 5.35 × 10-7 M ( S/ N = 3). In addition, the sensor has a fast response (Co3O4.

  2. Functionalization of carbon buckypaper for the sensitive determination of hydrogen peroxide in human urine.

    Science.gov (United States)

    Chatterjee, Sanghamitra; Chen, Aicheng

    2012-05-15

    Here we report on a new approach for the electrochemical detection of hydrogen peroxide (H(2)O(2)) based on the co-immobilization of horseradish peroxidase and methylene blue on the functionalized carbon buckypaper supported by a titanium substrate. Cyclic voltammetry was used to study and optimize the performance of the resulting electrochemical biosensor. The proposed biosensor exhibited high analytical performance towards the quantification of H(2)O(2) at the physiological pH 7.4. Under optimized conditions, the biosensor shows a wide linear response range from 0.1 × 10(-6) to 5 × 10(-4)M concentrations of H(2)O(2). The detection limit was determined to be 7.5 × 10(-8)M (based on S/N=3). Reproducibility and stability of the fabricated biosensor were examined with satisfactory results. The biological relevance of the developed electrochemical biosensor has been further studied by the determination of H(2)O(2) in human urine samples of normal volunteers prior to and following the ingestion of coffee. Increased levels of urinary H(2)O(2) concentration suggest that oxidative stress is induced by coffee drinking in humans. There is considerable interest in oxidative stress as relates to human physiology. The sensitive determination of H(2)O(2) in human urine may serve as a valuable biomarker to effectively elucidate specific levels of oxidative stress in vivo. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. A new method for removal of hydrogen peroxide interference in the analysis of chemical oxygen demand.

    Science.gov (United States)

    Wu, Tingting; Englehardt, James D

    2012-02-21

    Many advanced oxidation processes involve addition of hydrogen peroxide (H(2)O(2)) with the aim of generating hydroxyl radicals to oxidize organic contaminants in water. However, chemical oxygen demand, a common measure of gross residual organic contamination, is subject to interference from residual H(2)O(2) in the treated water. A new method, involving catalytic decomposition of H(2)O(2) with addition of heat and sodium carbonate (Na(2)CO(3)), is proposed in this work to address this problem. The method is demonstrated experimentally, and modeled kinetically. Results for 5 mM H(2)O(2) in deionized (DI) water included reduction to below the COD detection limit after 60 min heating (90(◦)C) with addition of 20 g/L Na(2)CO(3) concentrated solution, whereas 900 min were required in treated municipal wastewater. An approximate second order rate constant of 11.331 M(-1)·min(-1) at Na(2)CO(3) dosage of 20 g/L was found for the tested wastewater. However, kinetic modeling indicated a two-step reaction mechanism, with formation of peroxocarbonate (CO(4)(2-)) and ultimate decomposition to H(2)O and O(2) in pure H(2)O(2) solution. A similar mechanism is apparent in wastewater at high catalyst concentrations, whereas at low Na(2)CO(3) addition rates, the catalytic effects of other constituents appear important.

  4. Stabilizing the bactericidal activity of hydrogen peroxide: a brand new function of certain Chinese herbs.

    Science.gov (United States)

    Li, Wan-zhen; Tan, Ling-ling; Li, Qi-jie; Zhou, Bang-jing; Gao, Yong-xiang; Ding, Wei-jun

    2014-06-01

    To explore natural herbs to maintain the bactericidal activity of hydrogen peroxide (H). Eighteen extracts of Chinese herbs were prepared complying with the standard protocol. Each of the solutions was then mixed with 1% H2O2. The mixtures were handled with two approaches: autoclaved daily for one, two or three times; stored at room temperature from one through five years. Then the bactericidal activity were evaluated by assaying the minimal bactericidal concentration (MBC) and minimal inhibitory concentration (MIC) against Gram positive (Staphylococcus aureus, ATCC25923) and Gram negative (Escherichia coli, ATCC12421) bacteria. While mixed with 1% H2O2, 10 out of 18 kinds of assessed Chinese herbs displayed MBC values at 1:12800 or higher after three times of autoclaving, and 8 of them preserved such level of MBC value after stored at room temperature for three years. Some Chinese herbs, i.e. R. Scutellariae, R. Coptidis, R. Bupleuri, H. Epimedii, C. Phelledendri and F. Chrysanthemi, can significantly maintain the bactericidal activity of diluted H2O2. Certain Chinese herbs can effectively stabilize the bactericidal activity of H2O2 undergoing autoclave or long-term storage. This paper reported a brandnew pharmaceutical function of Chinese herbs and provided experimental data for the potential enhancement of H2O2 usage while its stability level is promoted.

  5. Fabrication of a novel electrochemical sensor for determination of hydrogen peroxide in different fruit juice samples

    Directory of Open Access Journals (Sweden)

    Navid Nasirizadeh

    2016-01-01

    Full Text Available A new hydrogen peroxide (H2O2 sensor is fabricated based on a multiwalled carbon nanotube-modified glassy carbon electrode (MWCNT-GCE and reactive blue 19 (RB. The charge transfer coefficient, α, and the charge transfer rate constant, ks, of RB adsorbed on MWCNT-GCE were calculated and found to be 0.44 ± 0.01 Hz and 1.9 ± 0.05 Hz, respectively. The catalysis of the electroreduction of H2O2 by RB-MWCNT-GCE is described. The RB-MWCNT-GCE shows a dramatic increase in the peak current and a decrease in the overvoltage of H2O2 electroreduction in comparison with that seen at an RB modified GCE, MWCNT modified GCE, and activated GCE. The kinetic parameters such as α and the heterogeneous rate constant, k', for the reduction of H2O2 at RB-MWCNT-GCE surface were determined using cyclic voltammetry. The detection limit of 0.27μM and three linear calibration ranges were obtained for H2O2 determination at the RB-MWCNT-GCE surface using an amperometry method. In addition, using the newly developed sensor, H2O2 was determined in real samples with satisfactory results.

  6. Fabrication of a novel electrochemical sensor for determination of hydrogen peroxide in different fruit juice samples.

    Science.gov (United States)

    Nasirizadeh, Navid; Shekari, Zahra; Nazari, Ali; Tabatabaee, Masoumeh

    2016-01-01

    A new hydrogen peroxide (H2O2) sensor is fabricated based on a multiwalled carbon nanotube-modified glassy carbon electrode (MWCNT-GCE) and reactive blue 19 (RB). The charge transfer coefficient, α, and the charge transfer rate constant, ks, of RB adsorbed on MWCNT-GCE were calculated and found to be 0.44 ± 0.01 Hz and 1.9 ± 0.05 Hz, respectively. The catalysis of the electroreduction of H2O2 by RB-MWCNT-GCE is described. The RB-MWCNT-GCE shows a dramatic increase in the peak current and a decrease in the overvoltage of H2O2 electroreduction in comparison with that seen at an RB modified GCE, MWCNT modified GCE, and activated GCE. The kinetic parameters such as α and the heterogeneous rate constant, k', for the reduction of H2O2 at RB-MWCNT-GCE surface were determined using cyclic voltammetry. The detection limit of 0.27μM and three linear calibration ranges were obtained for H2O2 determination at the RB-MWCNT-GCE surface using an amperometry method. In addition, using the newly developed sensor, H2O2 was determined in real samples with satisfactory results. Copyright © 2015. Published by Elsevier B.V.

  7. Kinetics of oxidation of bilirubin and its protein complex by hydrogen peroxide in aqueous solutions

    Science.gov (United States)

    Solomonov, A. V.; Rumyantsev, E. V.; Antina, E. V.

    2010-12-01

    A comparative study of oxidation reactions of bilirubin and its complex with albumin was carried out in aqueous solutions under the action of hydrogen peroxide and molecular oxygen at different pH values. Free radical oxidation of the pigment in both free and bound forms at pH 7.4 was shown not to lead to the formation of biliverdin, but to be associated with the decomposition of the tetrapyrrole chromophore into monopyrrolic products. The effective and true rate constants of the reactions under study were determined. It was assumed that one possible mechanism of the oxidation reaction is associated with the interaction of peroxyl radicals and protons of the NH groups of bilirubin molecules at the limiting stage with the formation of a highly reactive radical intermediate. The binding of bilirubin with albumin was found to result in a considerable reduction in the rate of the oxidation reaction associated with the kinetic manifestation of the protein protection effect. It was found that the autoxidation of bilirubin by molecular oxygen with the formation of biliverdin at the intermediate stage can be observed with an increase in the pH of solutions.

  8. High Strength and Compatible Aluminum Alloy for Hydrogen-Peroxide Fuel Tanks

    Science.gov (United States)

    Lee, Jonathan A.

    2004-01-01

    This paper describes the development of a new high strength and Hydrogen Peroxide (HP) propellant compatible aluminum alloy for NASA Hyper-X vehicle's fuel tanks and structures. The tensile strength of the new alloy is more than 3 times stronger than the conventional 5254 alloy while it still maintains HP compatibility similar to 5254 (Class 1 category). The alloy development strategy consists of selecting certain rare earth and transition metals, with unique electrochemical properties, that will not act as catalysts to decompose liquid HP at the atomic level. Such elements will added to the aluminum alloy and the mixture will be cast and rolled into thin sheet metals. Test coupons are machined from sheet metals for HP long-term exposure testing and mechanical properties testing. In addition, the ability to weld the new alloy using Friction Stir Welding has also been explored. Currently, aluminum alloy 5254 is the state-of-the-art material for HP storage, but its yield strength is very low (420 ksi) and may not be suitable for the development of light-weight fuel tanks for Hyper-X vehicles. The new high strength and HP compatible alloy could represent an enabling material technology for NASA's Hyper-X vehicles, where flight weight reduction is a critical requirement. These X-planes are currently under studied as air-breathing hypersonic research vehicles featuring a lifting body configuration with a Rocket Based Combined Cycle (RBCC) engine system.

  9. All-Weather Hydrogen Peroxide-Based Decontamination of CBRN Contaminants

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, George W. [U.S. Army Edgewood Chemical Biological Center (ECBC), Aberdeen Proving Ground, MD (United States); Procell, Lawrence R. [U.S. Army Edgewood Chemical Biological Center (ECBC), Aberdeen Proving Ground, MD (United States); Sorrick, David C. [U.S. Army Edgewood Chemical Biological Center (ECBC), Aberdeen Proving Ground, MD (United States); Lawson, Glenn E. [Naval Surface Warfare Center (NSWC), Dahlgren, VA (United States); Wells, Claire M. [Naval Surface Warfare Center (NSWC), Dahlgren, VA (United States); Reynolds, Charles M. [U.S. Army Cold Regions Research and Engineering Lab. (CRREL), Hanover, NH (United States); Ringelberg, D. B. [U.S. Army Cold Regions Research and Engineering Lab. (CRREL), Hanover, NH (United States); Foley, Karen L. [U.S. Army Cold Regions Research and Engineering Lab. (CRREL), Hanover, NH (United States); Lumetta, Gregg J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Blanchard, David L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2010-03-11

    A hydrogen peroxide-based decontaminant, Decon Green, is efficacious for the decontamination of chemical agents VX (S-2-(diisopropylamino)ethyl O-ethyl methylphosphonothioate), GD (Soman, pinacolyl methylphosphonofluoridate), and HD (mustard, bis(2-chloroethyl) sulfide); the biological agent anthrax (Bacillus anthracis); and radiological isotopes Cs-137 and Co-60; thus demonstrating the ability of this decontamination approach to ameliorate the aftermath of all three types of weapons of mass destruction (WMD). Reaction mechanisms afforded for the chemical agents are discussed as are rationales for the enhanced removal efficacy of recalcitrant 60Co on certain surfaces. Decontaminants of this nature can be deployed, and are effective, at very low temperatures (-32 °C), as shown for studies done with VX and HD simulants, without the need for external heat sources. Finally, the efficacy of a lower-logistics, dry decontaminant powder concentrate (utilizing the solid active-oxygen compounds peracetyl borate and Peroxydone) which can be reconstituted with water in the field prior to use, is presented.

  10. PA-Tb-Cu MOF as luminescent nanoenzyme for catalytic assay of hydrogen peroxide.

    Science.gov (United States)

    Qi, Zewan; Wang, Li; You, Qi; Chen, Yang

    2017-10-15

    Metal organic frameworks (MOFs) with flexible structures and components have aroused great interest in designing functional materials. In this work, we designed and made a kind of PA-Tb-Cu MOF nanoenzyme capable of emitting fluorescence for the catalytic reaction of hydrogen peroxide (H 2 O 2 ). Luminescent Tb 3+ , catalytic Cu 2+ and bridging ligand were assembled and integrated into a single material nanoenzyme. This PA-Tb-Cu MOF nanoenzyme not only possessed excellent catalytic activity comparable to horseradish peroxidase but also can real-time fluorescently indicate the concentration of H 2 O 2 as low as 0.2µM during catalysis. Luminescent PA-Tb-Cu MOF nanoenzyme did not need a common combined use of natural/artificial enzymes and chromogenic reactions for the quantification of H 2 O 2 in widely-used enzyme-catalytic reactions. The present strategy assembled directly from functional ions/molecules provides a new way for the design and development of smart, multifunctional artificial enzymes for wide applications in biocatalysis, bioassays and nano-biomedicine. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Pistacia lentiscus fruit oil reduces oxidative stress in human skin explants caused by hydrogen peroxide.

    Science.gov (United States)

    Ben Khedir, S; Moalla, D; Jardak, N; Mzid, M; Sahnoun, Z; Rebai, T

    2016-10-01

    We investigated the efficacy of Pistacia lentiscus fruit oil (PLFO) for protecting human skin from damage due to oxidative stress. PLFO contains natural antioxidants including polyphenols, sterols and tocopherols. We compared the antioxidant potential of PLFO with extra virgin olive oil (EVOO). Explants of healthy adult human skin were grown in culture with either PLFO or EVOO before adding hydrogen peroxide (H2O2). We also used cultured skin explants to investigate the effects of PLFO on lipid oxidation and depletion of endogenous antioxidant defense enzymes including glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT) one day after 2 h exposure to H2O2. We found that PLFO scavenged radicals and protected skin against oxidative injury. PLFO exhibited greater antioxidant and free radical scavenging activity than EVOO. Skin explants treated with PLFO inhibited H2O2 induced MDA formation by inhibition of lipid oxidation. In addition, the oil inhibited H2O2 induced depletion of antioxidant defense enzymes including GPx, SOD and CAT. We found that treatment with PLFO repaired skin damage owing to its antioxidant properties.

  12. Redox Response of Reduced Graphene Oxide-Modified Glassy Carbon Electrodes to Hydrogen Peroxide and Hydrazine

    Directory of Open Access Journals (Sweden)

    Jun-ichi Anzai

    2013-05-01

    Full Text Available The surface of a glassy carbon (GC electrode was modified with reduced graphene oxide (rGO to evaluate the electrochemical response of the modified GC electrodes to hydrogen peroxide (H2O2 and hydrazine. The electrode potential of the GC electrode was repeatedly scanned from −1.5 to 0.6 V in an aqueous dispersion of graphene oxide (GO to deposit rGO on the surface of the GC electrode. The surface morphology of the modified GC electrode was characterized by scanning electron microscopy (SEM and atomic force microscopy (AFM. SEM and AFM observations revealed that aggregated rGO was deposited on the GC electrode, forming a rather rough surface. The rGO-modified electrodes exhibited significantly higher responses in redox reactions of H2O2 as compared with the response of an unmodified GC electrode. In addition, the electrocatalytic activity of the rGO-modified electrode to hydrazine oxidation was also higher than that of the unmodified GC electrode. The response of the rGO-modified electrode was rationalized based on the higher catalytic activity of rGO to the redox reactions of H2O2 and hydrazine. The results suggest that rGO-modified electrodes are useful for constructing electrochemical sensors.

  13. Applicability of hydrogen peroxide in brown tide control - culture and microcosm studies.

    Science.gov (United States)

    Randhawa, Varunpreet; Thakkar, Megha; Wei, Liping

    2012-01-01

    Brown tide algal blooms, caused by the excessive growth of Aureococcus anophagefferens, recur in several northeastern US coastal bays. Direct bloom control could alleviate the ecological and economic damage associated with bloom outbreak. This paper explored the effectiveness and safety of natural chemical biocide hydrogen peroxide (H(2)O(2)) for brown tide bloom control. Culture studies showed that H(2)O(2) at 1.6 mg L(-1) effectively eradicated high density A. anophagefferens within 24-hr, but caused no significant growth inhibition in the diatoms, prymnesiophytes, green algae and dinoflagellates of >2-3 μm cell sizes among 12 phytoplankton species tested over 1-week observation. When applied to brown tide bloom prone natural seawater in a microcosm study, this treatment effectively removed the developing brown tide bloom, while the rest of phytoplankton assemblage (quantified via HPLC based marker pigment analyses), particularly the diatoms and green algae, experienced only transient suppression then recovered with total chlorophyll a exceeding that in the controls within 72-hr; cyanobacteria was not eradicated but was still reduced about 50% at 72-hr, as compared to the controls. The action of H(2)O(2) against phytoplankton as a function of cell size and cell wall structure, and a realistic scenario of H(2)O(2) application were discussed.

  14. Coupling mechanism between wear and oxidation processes of 304 stainless steel in hydrogen peroxide environments.

    Science.gov (United States)

    Dong, Conglin; Yuan, Chengqing; Bai, Xiuqin; Li, Jian; Qin, Honglin; Yan, Xinping

    2017-05-24

    Stainless steel is widely used in strongly oxidizing hydrogen peroxide (H2O2) environments. It is crucial to study its wear behaviour and failure mode. The tribological properties and oxidation of 304 stainless steel were investigated using a MMW-1 tribo-tester with a three-electrode setup in H2O2 solutions with different concentrations. Corrosion current densities (CCDs), coefficients of frictions (COFs), wear mass losses, wear surface topographies, and metal oxide films were analysed and compared. The results show that the wear process and oxidation process interacted significantly with each other. Increasing the concentration of H2O2 or the oxidation time was useful to form a layer of integrated, homogeneous, compact and thick metal oxide film. The dense metal oxide films with higher mechanical strengths improved the wear process and also reduced the oxidation reaction. The wear process removed the metal oxide films to increase the oxidation reaction. Theoretical data is provided for the rational design and application of friction pairs in oxidation corrosion conditions.

  15. Beneficial effects of hydroxyapatite on enamel subjected to 30% hydrogen peroxide.

    Science.gov (United States)

    Jiang, Tao; Ma, Xiao; Wang, Zhejun; Tong, Hua; Hu, Jiming; Wang, Yining

    2008-11-01

    To evaluate the effect of combination of hydroxyapatite (HA) and hydrogen peroxide (HP) on color, microhardness and morphology of human tooth enamel. Forty-eight human dental blocks were obtained from 12 pairs of premolars and were randomly divided into four groups. Group DW was treated with distilled water, group HP with 30% HP, group HA+DW with HA mixed with distilled water and group HA+HP with HA mixed with 30% HP. Baseline and final color measurements and microhardness test were carried out before and after bleaching experiments. Two specimens from each group were selected for morphological investigation after final tests. The DeltaE of group HP and HA+HP were significantly higher than those of group DW (p=0.000 and p=0.000) and group HA+DW (p=0.000 and p=0.000). The percentage microhardness loss of group HA+HP was significantly lower than that of group HP (p=0.047), but significantly higher than those of group DW (p=0.000) and group HA+DW (p=0.000). The obvious variation of morphology was only observed on enamel surfaces in group HP. This study suggested that combination of HA and HP was effective in tooth whitening. HA could significantly reduce the microhardness loss of enamel caused by 30% HP and keep enamel surface morphology almost unchanged.

  16. Facile Fabrication of a Gold Nanocluster-Based Membrane for the Detection of Hydrogen Peroxide

    Directory of Open Access Journals (Sweden)

    Pu Zhang

    2016-07-01

    Full Text Available In this work, we present a simple and rapid method to synthesize red luminescent gold nanoclusters (AuNCs with high quantum yield (QY, ~16%, excellent photostability and biocompatibility. Next, we fabricated a solid membrane by loading the as-prepared AuNCs in an agar matrix. Different from nanomaterials dispersed in solution, the AuNCs-based solid membrane has distinct advantages including convenience of transportation, while still maintaining strong red luminescence, and relatively long duration storage without aggregation. Taking hydrogen peroxide (H2O2 as a typical example, we then employed the AuNCs as a luminescent probe and investigated their sensing performance, either in solution phase or on a solid substrate. The detection of H2O2 could be achieved in wide concentration ranges over 805 nM–1.61 mM and 161 μM–19.32 mM in solution and on a solid membrane, respectively, with limits of detection (LOD of 80 nM and 20 μM. Moreover, the AuNCs-based membrane could also be used for visual detection of H2O2 in the range of 0–3.22 mM. In view of the convenient synthesis route and attractive luminescent properties, the AuNCs-based membrane presented in this work is quite promising for applications such as optical sensing, fluorescent imaging, and photovoltaics.

  17. Antibacterial effect of hydrogen peroxide-titanium dioxide suspensions in the decontamination of rough titanium surfaces.

    Science.gov (United States)

    Wiedmer, David; Petersen, Fernanda Cristina; Lönn-Stensrud, Jessica; Tiainen, Hanna

    2017-07-01

    The chemical decontamination of infected dental implants is essential for the successful treatment of peri-implantitis. The aim of this study was to assess the antibacterial effect of a hydrogen peroxide-titanium dioxide (H 2 O 2 -TiO 2 ) suspension against Staphylococcus epidermidis biofilms. Titanium (Ti) coins were inoculated with a bioluminescent S. epidermidis strain for 8 h and subsequently exposed to H 2 O 2 with and without TiO 2 nanoparticles or chlorhexidine (CHX). Bacterial regrowth, bacterial load and viability after decontamination were analyzed by continuous luminescence monitoring, live/dead staining and scanning electron microscopy. Bacterial regrowth was delayed on surfaces treated with H 2 O 2 -TiO 2 compared to H 2 O 2 . H 2 O 2 -based treatments resulted in a lower bacterial load compared to CHX. Few viable bacteria were found on surfaces treated with H 2 O 2 and H 2 O 2 -TiO 2 , which contrasted with a uniform layer of dead bacteria for surfaces treated with CHX. H 2 O 2 -TiO 2 suspensions could therefore be considered an alternative approach in the decontamination of dental implants.

  18. Identification of 4 ataxia telangiectasia cell lines hypersensitive to. gamma. -irradiation but not to hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Cantoni, O.; Sestili, P.; Santoro, M.P.; Tannoia, M.C.; Cattabeni, F. (Universita degli Studi di Urbino (Italy). Istituto di Farmacologia e Farmacognosia and Centro di Farmacologia Oncologia Sperimentale); Novelli, G.; Dallapiccola, B. (Universit degli Studi di Urbino (Italy). Cattedra di Genetica); Fiorilli, M. (Universita di Roma ' La Sapienze' (Italy). Cattedra di Allergologia e Immunologia Clinica)

    1989-09-01

    The effct of hydrogen peroxide on the rate of semi-conservative DNA synthesis in ataxia telangiectasia (AT) and normal human lymphoblastoid cells was investigated. The rate of DNA synthesis in AT cells was not depressed to a lesser extent than in normal cells, as might have been expected since H{sub 2O2} is a radiomimetic agent. On the contrary, 4 AT cell lines displayed a higher sensitivity to the inhibitory effect of H{sub 2O2} on DNA synthesis than 2 normal cell lines. Comparable levels of cytotoxicity were detected in cell vaibility studies. Furthermore, neither the level of DNA breakage produced by H{sub 2O2}, nor the rate of repair of these lesions was signigicantly different in normal and AT cells. Together, these results indicate that the AT cell lines utilized in this study are not hypersensitive to the oxidant. It is suggested that H-2-O-2 may not induce lethality via the direct ation of the hydroxyl radical (OH). (Author). 20 refs.; 3 figs.; 1 tab.

  19. Use of hydrogen peroxide vapour & plasma irradiation in combination for quick decontamination of closed chambers.

    Science.gov (United States)

    Mourya, Devendra T; Shahani, Hamish C; Yadav, Pragya D; Barde, Pradip V

    2016-08-01

    Various conventional methods such as gaseous, vapour and misting systems, fogging, manual spray and wipe techniques employing a number of chemical agents are used for decontamination of enclosed spaces. Among all these methods, use of aerosolized formaldehyde is the most preferred method due to cost-effectiveness and practical aspects. However, being extremely corrosive in nature generating very irritating fumes and difficulty in maintaining a high level of gas concentration, many laboratories prefer the vaporization of hydrogen peroxide (H 2 O 2 ) as an alternative. We present here the results of using H 2 O 2 vapour in combination with plasma irradiation for quick decontamination of closed chambers. The present study describes a decontamination method, using plasma irradiation in combination with H 2 O 2 (5%). Effect of plasma irradiation and H 2 O 2 on the viability of bacterial spores (Bacillus subtilis), Chikungunya and Kyasanur Forest Disease viruses was assessed. Data suggest that with the combination of H 2 O 2 vapour and plasma irradiation, within short time (three minutes), decontamination of surfaces and space volume could be achieved. Although it showed damage of spores present on the strips, it did not show any penetration power. The results were encouraging, and this method was found to be efficient for achieving surface sterilization in a short time. This application may be useful in laboratories and industries particularly, those working on clean facility concept following good laboratory and manufacturing practices.

  20. Use of hydrogen peroxide vapour & plasma irradiation in combination for quick decontamination of closed chambers

    Directory of Open Access Journals (Sweden)

    Devendra T Mourya

    2016-01-01

    Full Text Available Background & objectives: Various conventional methods such as gaseous, vapour and misting systems, fogging, manual spray and wipe techniques employing a number of chemical agents are used for decontamination of enclosed spaces. Among all these methods, use of aerosolized formaldehyde is the most preferred method due to cost-effectiveness and practical aspects. However, being extremely corrosive in nature generating very irritating fumes and difficulty in maintaining a high level of gas concentration, many laboratories prefer the vaporization of hydrogen peroxide (H 2 O 2 as an alternative. We present here the results of using H 2 O 2 vapour in combination with plasma irradiation for quick decontamination of closed chambers. Methods: The present study describes a decontamination method, using plasma irradiation in combination with H 2 O 2 (5%. Effect of plasma irradiation and H 2 O 2 on the viability of bacterial spores (Bacillus subtilis, Chikungunya and Kyasanur Forest Disease viruses was assessed. Results: Data suggest that with the combination of H 2 O 2 vapour and plasma irradiation, within short time (three minutes, decontamination of surfaces and space volume could be achieved. Although it showed damage of spores present on the strips, it did not show any penetration power. Interpretation & conclusions: The results were encouraging, and this method was found to be efficient for achieving surface sterilization in a short time. This application may be useful in laboratories and industries particularly, those working on clean facility concept following good laboratory and manufacturing practices.

  1. Effect of ascorbic acid and hydrogen peroxide on mouse neuroblastoma cells

    Science.gov (United States)

    HARDAWAY, CHRISITNA M.; BADISA, RAMESH B.; SOLIMAN, KARAM F.A.

    2012-01-01

    Ascorbic acid is one of the antioxidant compounds widely used against free radical stress. The present study was undertaken to examine whether ascorbic acid and hydrogen peroxide (H2O2), alone or in combination, could influence cell viability. The murine neuroblastoma cell line, N2a, was used to perform a dose response curve for ascorbic acid. It was observed that ascorbic acid alone at physiological concentrations (0.1–0.4 mM) did not cause any cell death. However, at pharmacological concentrations (1–6 mM), ascorbic acid caused dose-dependent cell death. The lethal concentration at which 50% cells were killed (LC50) was determined to be approximately 3.141 mM ascorbic acid at 24 h. H2O2 up to 300 μM alone did not cause significant cell death. In the combined treatment, when the cells were treated with ascorbic acid at physiological concentrations (0.4 mM) and H2O2 at 400 μM, higher rates of cell death were observed compared to the cell death rates caused by either compound alone. Subsequent experiments revealed that cell death was partly mediated through the loss of total glutathione levels in the cells. These data suggest that the combination of ascorbic acid and H2O2 is disadvantageous for cancer cell survival. Further studies are required to ascertain the physiological significance of these observations. PMID:22469841

  2. Elevation of hydrogen peroxide after spinal cord injury detected by using the Fenton reaction.

    Science.gov (United States)

    Liu, D; Liu, J; Wen, J

    1999-08-01

    To reveal whether reactive oxygen species (ROS) play a role after spinal cord injury, we developed a unique method for assaying hydrogen peroxide (H2O2) and determined the time course of its concentration changes following impact injury to the rat spinal cord. Microdialysis was used to sample H2O2 in the extracellular space and the dialysates were collected into a vial containing salicylate and ferrous chloride (FeCl2). H2O2 collected in the vial was converted to hydroxyl radicals (*OH) by FeCl2 catalysis. 2,3- and 2,5-dihydroxybenzoic acid produced by reaction of *OH with salicylate in the collecting vial were measured by HPLC and calibrated to H2O2 concentrations. The postinjury levels of H2O2 were significantly increased (p = 0.02) for over 11 h. FeCl2 administered through the dialysis fiber catalyzes H2O2 conversion in the cord to *OH. This *OH does not reach the collecting vial due to its extremely short lifetime (nanoseconds). The reduced H2O2 levels in the vials validate the measurement of H2O2. The relatively long-lasting formation of H2O2 and superoxide reported herein and previously suggests that ROS may be important in secondary spinal cord damage and that removal of ROS may be a realistic treatment strategy for reducing injury caused by free radicals.

  3. Wind-eroded silicate as a source of hydrogen peroxide on Mars

    DEFF Research Database (Denmark)

    Bak, Ebbe Norskov; Merrison, Jonathan P.; Jensen, Svend Knak

    Introduction: Investigations of Mars as a potential habitat for past or present life depend on understand-ing the chemistry of the Martian soil as it affects the preservation of organic compounds and thus the risk of forward contamination as well as the suitability of organic compounds as biomark......Introduction: Investigations of Mars as a potential habitat for past or present life depend on understand-ing the chemistry of the Martian soil as it affects the preservation of organic compounds and thus the risk of forward contamination as well as the suitability of organic compounds...... soil. Methods: We simulated wind-erosion of silicates by tumbling quartz sand in sealed quartz ampoules with defined atmospheres. The eroded sand was suspended in water and the hydrogen peroxide concentration was followed using a sco-poletin/horseradish peroxidase assay. Results: The simulated wind...... silicate could further affect the degradation of organic com-pounds on Mars, be a stress factor for past and present life as well as pose a danger to future Mars explorers. [1] Levin G. V. and Straat P.A. (1977) JGR, 82, 4663-4667. [2] Oyama V. I. and Berdahl B. J. (1977) JGR, 82, 4669-4676. [3] Zent A. P...

  4. Leaching of metals from large pieces of printed circuit boards using citric acid and hydrogen peroxide.

    Science.gov (United States)

    Jadhav, Umesh; Su, C; Hocheng, Hong

    2016-12-01

    In the present study, the leaching of metals from large pieces of computer printed circuit boards (CPCBs) was studied. A combination of citric acid (0.5 M) and 1.76 M hydrogen peroxide (H2O2) was used to leach the metals from CPCB piece. The influence of system variables such as H2O2 concentration, concentration of citric acid, shaking speed, and temperature on the metal leaching process was investigated. The complete metal leaching was achieved in 4 h from a 4 × 4 cm CPCB piece. The presence of citric acid and H2O2 together in the leaching solution is essential for complete metal leaching. The optimum addition amount of H2O2 was 5.83 %. The citric acid concentration and shaking speed had an insignificant effect on the leaching of metals. The increase in the temperature above 30 °C showed a drastic effect on metal leaching process.

  5. Spore-based biosensor to monitor the microbicidal efficacy of gaseous hydrogen peroxide sterilization processes.

    Science.gov (United States)

    Oberländer, Jan; Mayer, Marlena; Greeff, Anton; Keusgen, Michael; Schöning, Michael J

    2018-05-01

    In this work, a spore-based biosensor is evaluated to monitor the microbicidal efficacy of sterilization processes applying gaseous hydrogen peroxide (H 2 O 2 ). The sensor is based on interdigitated electrode structures (IDEs) that have been fabricated by means of thin-film technologies. Impedimetric measurements are applied to study the effect of sterilization process on spores of Bacillus atrophaeus. This resilient microorganism is commonly used in industry to proof the sterilization efficiency. The sensor measurements are accompanied by conventional microbiological challenge tests, as well as morphological characterizations with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The sensor measurements are correlated with the microbiological test routines. In both methods, namely the sensor-based and microbiological one, a tailing effect has been observed. The results are evaluated and discussed in a three-dimensional calibration plot demonstrating the sensor's suitability to enable a rapid process decision in terms of a successfully performed sterilization. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. Reactive radical-driven bacterial inactivation by hydrogen-peroxide-enhanced plasma-activated-water

    Science.gov (United States)

    Wu, Songjie; Zhang, Qian; Ma, Ruonan; Yu, Shuang; Wang, Kaile; Zhang, Jue; Fang, Jing

    2017-08-01

    The combined effects of plasma activated water (PAW) and hydrogen peroxide (H2O2), PAW/HP, in sterilization were investigated in this study. To assess the synergistic effects of PAW/HP, S. aureus was selected as the test microorganism to determine the inactivation efficacy. Also, the DNA/RNA and proteins released by the bacterial suspensions under different conditions were examined to confirm membrane integrity. Additionally, the intracellular pH (pHi) of S. aureus was measured in our study. Electron spin resonance spectroscopy (ESR) was employed to identify the presence of radicals. Finally, the oxidation reduction potential (ORP), conductivity and pH were measured. Our results revealed that the inactivation efficacy of PAW/HP is much greater than that of PAW, while increased H2O2 concentration result in higher inactivation potential. More importantly, as compared with PAW, the much stronger intensity ESR signals and higher ORP in PAW/HP suggests that the inactivation mechanism of the synergistic effects of PAW/HP: more reactive oxygen species (ROS) and reactive nitrogen species (RNS), especially OH and NO radicals, are generated in PAW combined with H2O2 resulting in more deaths of the bacteria.

  7. Carbon Nanodots as Dual-Mode Nanosensors for Selective Detection of Hydrogen Peroxide

    Science.gov (United States)

    Shen, Cheng-Long; Su, Li-Xia; Zang, Jin-Hao; Li, Xin-Jian; Lou, Qing; Shan, Chong-Xin

    2017-07-01

    Hydrogen peroxide (H2O2) is an important product of oxidase-based enzymatic reactions, such as glucose/glucose oxidase (GOD) reaction. Therefore, the probing of generated H2O2 for achieving the detection of various carbohydrates and their oxidases is very significative. Herein, we report one kind of dual-emission carbon nanodots (CDs) that can serve as novel dual-mode nanosensors with both fluorometric and colorimetric output for the selective detection of H2O2. The dual-model nanosensors are established only by the undecorated dual-emission CDs, where significant fluorometric and colorimetric changes are observed with the addition of different concentrations of H2O2 in the CD solution, which benefit to the achievement of the naked-eye detection for H2O2. The mechanism of the nanosensors can be attributed to the fact that the external chemical stimuli like hydroxyl radicals from H2O2 bring about the change of surface properties and the aggregation of CDs, which dominate the emission and absorption of CDs. The constructed dual-mode nanosensors exhibit good biocompatibility and high selectivity toward H2O2 with a linear detection range spanning from 0.05 to 0.5 M and allow the detection of H2O2 as low as 14 mM.

  8. A Modified Fluorimetric Method for Determination of Hydrogen Peroxide Using Homovanillic Acid Oxidation Principle

    Directory of Open Access Journals (Sweden)

    Biswaranjan Paital

    2014-01-01

    Full Text Available Hydrogen peroxide (H2O2 level in biological samples is used as an important index in various studies. Quantification of H2O2 level in tissue fractions in presence of H2O2 metabolizing enzymes may always provide an incorrect result. A modification is proposed for the spectrofluorimetric determination of H2O2 in homovanillic acid (HVA oxidation method. The modification was included to precipitate biological samples with cold trichloroacetic acid (TCA, 5% w/v followed by its neutralization with K2HPO4 before the fluorimetric estimation of H2O2 is performed. TCA was used to precipitate the protein portions contained in the tissue fractions. After employing the above modification, it was observed that H2O2 content in tissue samples was ≥2 fold higher than the content observed in unmodified method. Minimum 2 h incubation of samples in reaction mixture was required for completion of the reaction. The stability of the HVA dimer as reaction product was found to be >12 h. The method was validated by using known concentrations of H2O2 and catalase enzyme that quenches H2O2 as substrate. This method can be used efficiently to determine more accurate tissue H2O2 level without using internal standard and multiple samples can be processed at a time with additional low cost reagents such as TCA and K2HPO4.

  9. Pre-clinical development of a hydrogen peroxide-inactivated West Nile virus vaccine.

    Science.gov (United States)

    Poore, Elizabeth A; Slifka, Dawn K; Raué, Hans-Peter; Thomas, Archana; Hammarlund, Erika; Quintel, Benjamin K; Torrey, Lindsay L; Slifka, Ariel M; Richner, Justin M; Dubois, Melissa E; Johnson, Lawrence P; Diamond, Michael S; Slifka, Mark K; Amanna, Ian J

    2017-01-05

    West Nile virus (WNV) is a mosquito-transmitted pathogen with a wide geographical range that can lead to long-term disability and death in some cases. Despite the public health risk posed by WNV, including an estimated 3 million infections in the United States alone, no vaccine is available for use in humans. Here, we present a scaled manufacturing approach for production of a hydrogen peroxide-inactivated whole virion WNV vaccine, termed HydroVax-001WNV. Vaccination resulted in robust virus-specific neutralizing antibody responses and protection against WNV-associated mortality in mice or viremia in rhesus macaques (RM). A GLP-compliant toxicology study performed in rats demonstrated an excellent safety profile with clinical findings limited to minor and transient irritation at the injection site. An in vitro relative potency (IVRP) assay was developed and shown to correlate with in vivo responses following forced degradation studies. Long-term in vivo potency comparisons between the intended storage condition (2-8°C) and a thermally stressed condition (40±2°C) demonstrated no loss in vaccine efficacy or protective immunity over a 6-month span of time. Together, the positive pre-clinical findings regarding immunogenicity, safety, and stability indicate that HydroVax-001WNV is a promising vaccine candidate. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Electrosynthesis of bismuth nanodendrites/gallium nitride electrode for non-enzymatic hydrogen peroxide detection.

    Science.gov (United States)

    Jiang, Qing-Mei; Zhang, Miao-Rong; Luo, Li-Qiang; Pan, Ge-Bo

    2017-08-15

    Bismuth nanodendrites (BiNDs) were electrodeposited on planar gallium nitride (GaN) electrode via a differential pulse voltammetric technique to fabricate the non-enzymatic hydrogen peroxide (H2O2) sensor. SEM images revealed that the as-obtained BiNDs had numerous dendrite sub-branches, whose diameters ranged from 136 to 152nm. The BiNDs/GaN electrode showed linear amperometric responses for H2O2 in the concentration range from 10µM to 1mM with the sensitivity of 60.0μAmM(-1)cm(-2). Another linear range was from 1 to 10mM with the sensitivity of 23.3μAmM(-1)cm(-2). The limit of detection (LOD) was 5µM with the signal-to-noise ratio of 3. The applicability of the sensor was investigated to the H2O2 detection in real samples such as fetal bovine serum and milk, and the sensor exhibited excellent anti-interference capacity. The achieved results indicate that the as-prepared BiNDs/GaN sensor with good reproducibility and long-term stability was promising for detecting H2O2 in practical environments. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. A modified FOX-1 method for Micro-determination of hydrogen peroxide in honey samples.

    Science.gov (United States)

    Li, Dan; Wang, Meng; Cheng, Ni; Xue, Xiaofeng; Wu, Liming; Cao, Wei

    2017-12-15

    Hydrogen peroxide (H 2 O 2 ) is a major antibacterial activity-associated biomarker in honey. Measurement of endogenous H 2 O 2 in honey is of great value in prediction of the H 2 O 2 -depended antibacterial activity and characterization or selection of honey samples for their use as an antibacterial agent or natural food preservative. Considering current methods for H 2 O 2 determination are either time-consuming or complicated with their high-cost, a study was conducted to modify and validate the spectrophotometry-based ferrous oxidation-xylenol orange (FOX-1) method for micro-determination of H 2 O 2 in honey samples. The result suggested that the proposed FOX-1 method is fast, sensitive, precise and repeatable. The method was successfully applied for the analysis of a total of 35 honey samples from 5 floral origins and 33 geographical origins. The proposed method is low-cost and easy-to-run, and it can be considered by researchers and industry for routine analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Growth, photosynthesis, and antioxidant responses of Vigna unguiculata L. treated with hydrogen peroxide

    Directory of Open Access Journals (Sweden)

    Syed Aiman Hasan

    2016-12-01

    Full Text Available Cowpea (Vigna unguiculata L. is an important legume well grown in semiarid and arid environment. Hydrogen peroxide solutions (0.1, 0.5, 1.0, and 1.5 mM have been used to optimize growth and photosynthetic performance of cowpea plant at two growth stages [30 and 45 DAS (days of sowing]. Foliar application of H2O2 at 0.5 > 1.0 mM solution at 29 DAS optimally promoted the photosynthetic attributes [leaf chlorophyll content, net photosynthetic rate (PN, water use efficiency, and maximum quantum yield of PSII (Fv/Fm] and growth performance [root and shoot length; fresh and dry weight] of plants where the responses were more significant at the later growth stage. It was favored by activity of enzymes as carbonic anhydrase [CA; E.C. 4.2.1.1] and nitrate reductase [NR, E.C. 1.6.6.1] and those of antioxidant enzymes viz. peroxidase [POX; EC 1.11.1.7], catalase [CAT; EC 1.11.1.6], and superoxide dismutase [SOD; EC 1.15.1.1] and leaf proline content. Strengthened root system and antioxidant activity, particularly leaf proline level appeared to be the key factor for efficient photosynthesis and growth responses.

  13. Electrochemical Sensing of Hydrogen Peroxide Using Block Copolymer Templated Iron Oxide Nanopatterns.

    Science.gov (United States)

    Bas, Salih Z; Cummins, Cian; Borah, Dipu; Ozmen, Mustafa; Morris, Michael A

    2017-12-21

    A new enzyme-free sensor based on iron oxide (Fe3O4) nanodots fabricated on an indium tin oxide (ITO) substrate via a block copolymer template was developed for highly sensitive and selective detection of hydrogen peroxide (H2O2). The self-assembly-based process described here for Fe3O4 formation is a simple, cost-effective, and reproducible process. The H2O2 response of the fabricated electrodes was linear from 2.5 × 10-3 to 6.5 mM with a sensitivity of 191.6 μA mM-1cm-2 and a detection limit of 1.1 × 10-3 mM. The electrocatalytic activity of Fe3O4 nanodots toward the electroreduction of H2O2 was described by cyclic voltammetric and amperometric techniques. The sensor described here has a strong anti-interference ability to a variety of common biological and inorganic substances.

  14. A tissue-scale gradient of hydrogen peroxide mediates rapid wound detection in zebrafish.

    Science.gov (United States)

    Niethammer, Philipp; Grabher, Clemens; Look, A Thomas; Mitchison, Timothy J

    2009-06-18

    Barrier structures (for example, epithelia around tissues and plasma membranes around cells) are required for internal homeostasis and protection from pathogens. Wound detection and healing represent a dormant morphogenetic program that can be rapidly executed to restore barrier integrity and tissue homeostasis. In animals, initial steps include recruitment of leukocytes to the site of injury across distances of hundreds of micrometres within minutes of wounding. The spatial signals that direct this immediate tissue response are unknown. Owing to their fast diffusion and versatile biological activities, reactive oxygen species, including hydrogen peroxide (H(2)O(2)), are interesting candidates for wound-to-leukocyte signalling. Here we probe the role of H(2)O(2) during the early events of wound responses in zebrafish larvae expressing a genetically encoded H(2)O(2) sensor. This reporter revealed a sustained rise in H(2)O(2) concentration at the wound margin, starting approximately 3 min after wounding and peaking at approximately 20 min, which extended approximately 100-200 microm into the tail-fin epithelium as a decreasing concentration gradient. Using pharmacological and genetic inhibition, we show that this gradient is created by dual oxidase (Duox), and that it is required for rapid recruitment of leukocytes to the wound. This is the first observation, to our knowledge, of a tissue-scale H(2)O(2) pattern, and the first evidence that H(2)O(2) signals to leukocytes in tissues, in addition to its known antiseptic role.

  15. Date seed oil limit oxidative injuries induced by hydrogen peroxide in human skin organ culture.

    Science.gov (United States)

    Dammak, Ines; Abdallah, Fatma Ben; Boudaya, Sonia; Besbes, Souhail; Keskes, Leila; El Gaied, Amel; Turki, Hamida; Attia, Hammadi; Hentati, Basma

    2007-01-01

    The skin is chronically exposed to pro-oxidant agents, leading to the generation of reactive oxygen species (ROS). To protect the skin against an over-load of oxidant species, we studied the chemoprotective effect of one new natural product: "date seed oil: DSO". This oil may serve as a potential source of natural antioxidants such as phenols and tocopherols. Here, the antioxidative potential of DSO was compared that of to extra virgin olive oil. Adult human skin was maintained in organ culture in the presence of the DSO and extra virgin olive oil before the addition of hydrogen peroxide (H2O2), in order to prevent the tissue from its oxidizing effects. Skin specimens were collected for histology and for melanin studies. In the investigated model system, DSO protects skin against oxidative injuries. It has a significant chemoprotective effect, by inhibition of damage caused by H_{2}O_{2} compared with specimens without such addition endowing with a radical scavenging ability. The various components from DSO were much more potent antioxidant and more free radical scavengers of the H2O2 than those of olive oil. Our study shows that topical DSO treatment of the skin stimulates events in the epidermis leading to repair skin damage possibly due to antioxidant synergisms.

  16. Hydrogen peroxide contributes to the epithelial cell death induced by the oral mitis group of streptococci.

    Directory of Open Access Journals (Sweden)

    Nobuo Okahashi

    Full Text Available Members of the mitis group of streptococci are normal inhabitants of the commensal flora of the oral cavity and upper respiratory tract of humans. Some mitis group species, such as Streptococcus oralis and Streptococcus sanguinis, are primary colonizers of the human oral cavity. Recently, we found that hydrogen peroxide (H2O2 produced by S. oralis is cytotoxic to human macrophages, suggesting that streptococcus-derived H2O2 may act as a cytotoxin. Since epithelial cells provide a physical barrier against pathogenic microbes, we investigated their susceptibility to infection by H2O2-producing streptococci in this study. Infection by S. oralis and S. sanguinis was found to stimulate cell death of Detroit 562, Calu-3 and HeLa epithelial cell lines at a multiplicity of infection greater than 100. Catalase, an enzyme that catalyzes the decomposition of H2O2, inhibited S. oralis cytotoxicity, and H2O2 alone was capable of eliciting epithelial cell death. Moreover, S. oralis mutants lacking the spxB gene encoding pyruvate oxidase, which are deficient in H2O2 production, exhibited reduced cytotoxicity toward Detroit 562 epithelial cells. In addition, enzyme-linked immunosorbent assays revealed that both S. oralis and H2O2 induced interleukin-6 production in Detroit 562 epithelial cells. These results suggest that streptococcal H2O2 is cytotoxic to epithelial cells, and promotes bacterial evasion of the host defense systems in the oral cavity and upper respiratory tracts.

  17. Oxidation of triarylphosphines and aryl methyl sulfides with hydrogen peroxide catalyzed by dioxovanadium(V) ion.

    Science.gov (United States)

    Du, Guodong; Espenson, James H

    2005-04-04

    Although neither vanadium(V) ions nor hydrogen peroxide efficiently oxidize the title substrates, they do so in combination, with vanadium(V) as the catalyst in acidic aqueous acetonitrile. The kinetic data show that, of the two peroxovanadium species present, OV(O2)+ and OV(O2)2-, only the latter reacts at a detectable rate. This unanticipated result can be attributed to the weaker O-O and V-O bonds in the diperoxo complex. The rate constants for both series of substrates follow the Hammett correlation, with rhoP = -1.35 and rhoS = -0.83. To analyze properly the kinetic data for the Ar3P compounds, account must be taken of the protonation to Ar3PH+ in acidic solution. In retrospect, our earlier study [Abu-Omar, M. M.; Espenson, J. H. J. Am. Chem. Soc. 1995, 117, 272-280] of phosphine oxidation catalyzed by MeReO3 failed to do so, and the reaction constant must be corrected from the originally reported value to -1.56.

  18. Melanin Bleaching With Warm Hydrogen Peroxide and Integrated Immunohistochemical Analysis: An Automated Platform.

    Science.gov (United States)

    Liu, Chia-Hsing; Lin, Chih-Hung; Tsai, Min-Jan; Chen, Yu-Hsuan; Yang, Sheau-Fang; Tsai, Kun-Bow

    2018-02-01

    Diagnosing melanocytic lesions is among the most challenging problems in the practice of pathology. The difficulty of physically masking melanin pigment and the similarity of its color to commonly used chromogens often complicate examination of the cytomorphology and immunohistochemical staining results for tumor cells. Melanin bleach can be very helpful for histopathological diagnosis of heavily pigmented melanocytic lesions. Although various depigmentation methods have been reported, no standardized methods have been developed. This study developed a fully automated platform that incorporates hydrogen peroxide-based melanin depigmentation in an automated immunohistochemical analysis. The utility of the method was tested in 1 cell block of malignant melanoma cells in pleural effusion, 10 ocular melanoma tissue samples, and 10 cutaneous melanoma tissue samples. Our results demonstrated that the proposed method, which can be performed in only 3 hours, effectively preserves cell cytomorphology and immunoreactivity. The method is particularly effective for removing melanin pigment to facilitate histopathological examination of cytomorphology and for obtaining an unmasked tissue section for immunohistochemical analysis.

  19. Numerical study of hydrogen peroxide thermal decomposition in a shock tube

    Science.gov (United States)

    Bhatti, Muhammad Rizwan; Sheikh, Nadeem Ahmed; Manzoor, Shehryar; Khan, Muhammad Mahabat; Ali, Muzaffar

    2017-06-01

    Hydrogen peroxide (H2O2) has its significance during the combustion of heavy hydrocarbons in the internal combustion (IC) engines. Owing to its importance the measurements of H2O2 dissociation rate have been reported mostly using the shock tube apparatus. These types of experimental measurements are although quite reliable but require high cost. On the other hand, numerical simulations provide low cost and reliable solutions especially using computation fluid dynamics (CFD) software. In the current study an experimental shock tube flow is modeled using open access platform OpenFOAM to investigate the thermal decomposition of H2O2. Using two different convective schemes, limitedLinear and upwind, the propagation of shock wave and resultant dissociation reaction are simulated. The results of the simulations are compared with the experimental data. It is observed that the rate constant measured using the simulation data deviates from the experimental results in the low temperature range and approaches the experimental values as the temperature is raised.

  20. Recycling the liquid fraction of alkaline hydrogen peroxide in the pretreatment of corn stover.

    Science.gov (United States)

    Alencar, Bárbara Ribeiro Alves; Reis, Alexandre Libanio Silva; de Souza, Raquel de Fatima Rodrigues; Morais, Marcos Antônio; Menezes, Rômulo Simões Cezar; Dutra, Emmanuel Damilano

    2017-10-01

    The aim of this study was to evaluate the influence of recycling the liquid fraction of pretreatment with alkaline hydrogen peroxide (AHP) on the hydrolysis of corn stover. Corn stover was pretreated in the traditional condition with 7.5% v/v H 2 O 2 . After pretreatment, the solids were separated from the liquid fraction and five successive reuse cycles of the liquid fraction were tested. The solid fraction from pretreatment in each recycle was submitted to enzymatic hydrolysis. The number of recycles had a linear negative effect (R 2 =0.98) on biomass delignification efficiency and also affected negatively the enzymatic conversion efficiency. Despite the decrease in efficiency after each recycling step, reuse of the liquid fraction leads to reduction in water, H 2 O 2 and NaOH consumption of up to 57.6%, 59.6% and 57.6%, respectively. These findings point to an efficient recycling technology, which may reduce costs and save water. Copyright © 2017 Elsevier Ltd. All rights reserved.