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Sample records for added hydrogen peroxide

  1. Peroxide test strips detect added hydrogen peroxide in raw milk at levels affecting bacterial load.

    Martin, Nicole H; Friedlander, Adam; Mok, Allen; Kent, David; Wiedmann, Martin; Boor, Kathryn J

    2014-10-01

    Hydrogen peroxide (H2O2) has a long-established history of use as a preservative in milk worldwide. The use of H2O2 to activate the inherent lactoperoxidase enzyme system has dramatically improved the quality of raw dairy products in areas in which cooling is not widely available. In the United States, however, where refrigeration is widely available, the addition of H2O2 to milk is not permitted, with the exception of certain applications prior to cheesemaking and during the preparation of modified whey. Due to the relatively quick deterioration of H2O2 in fluid milk, the detection of raw milk adulterated with the compound can be challenging. In this study we evaluated (i) total aerobic bacterial counts and (ii) ability of peroxide test strips to detect H2O2 in raw milk with various concentrations (0, 100, 300, 500, 700, and 900 ppm) of added H2O2, incubated at both 6 and 21°C for 0, 24, and 48 h. Results showed that at both 6 and 21°C the H2O2 concentration and time had a significant effect on bacterial loads in raw milk. Additionally, commercially available test strips were able to detect H2O2 in raw milk, with predicted probability of >90%, immediately after addition and after 24 and 48 h for the higher concentrations used, offering a viable method for detecting raw milk adulteration with H2O2. PMID:25285503

  2. Concentration of Hydrogen Peroxide

    Parrish, Clyde F. (Inventor)

    2006-01-01

    Methods for concentrating hydrogen peroxide solutions have been described. The methods utilize a polymeric membrane separating a hydrogen peroxide solution from a sweep gas or permeate. The membrane is selective to the permeability of water over the permeability of hydrogen peroxide, thereby facilitating the concentration of the hydrogen peroxide solution through the transport of water through the membrane to the permeate. By utilizing methods in accordance with the invention, hydrogen peroxide solutions of up to 85% by volume or higher may be generated at a point of use without storing substantial quantities of the highly concentrated solutions and without requiring temperatures that would produce explosive mixtures of hydrogen peroxide vapors.

  3. Electrochemical Hydrogen Peroxide Generator

    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

  4. Progress toward hydrogen peroxide micropulsion

    Whitehead, J C; Dittman, M D; Ledebuhr, A G

    1999-07-08

    A new self-pressurizing propulsion system has liquid thrusters and gas jet attitude control without heavy gas storage vessels. A pump boosts the pressure of a small fraction of the hydrogen peroxide, so that reacted propellant can controllably pressurize its own source tank. The warm decomposition gas also powers the pump and is supplied to the attitude control jets. The system has been incorporated into a prototype microsatellite for terrestrial maneuvering tests. Additional progress includes preliminary testing of a bipropellant thruster, and storage of unstabilized hydrogen peroxide in small sealed tanks.

  5. 21 CFR 184.1366 - Hydrogen peroxide.

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Hydrogen peroxide. 184.1366 Section 184.1366 Food... Specific Substances Affirmed as GRAS § 184.1366 Hydrogen peroxide. (a) Hydrogen peroxide (H2O2, CAS Reg. No. 7722-84-1) is also referred to as hydrogen dioxide. It is made by the electrolytic oxidation...

  6. 21 CFR 582.1366 - Hydrogen peroxide.

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Hydrogen peroxide. 582.1366 Section 582.1366 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1366 Hydrogen peroxide. (a) Product. Hydrogen peroxide. (b) (c) Limitations,...

  7. 21 CFR 529.1150 - Hydrogen peroxide.

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Hydrogen peroxide. 529.1150 Section 529.1150 Food... DRUGS, FEEDS, AND RELATED PRODUCTS CERTAIN OTHER DOSAGE FORM NEW ANIMAL DRUGS § 529.1150 Hydrogen peroxide. (a) Specifications. Each milliliter of solution contains 396.1 milligrams (mg) hydrogen...

  8. Hydrogen peroxide as a greenhouse soil amendment

    There are anecdotal reports that hydrogen peroxide provides growth benefits beyond controlling plant infection and plant stress. The objective of this research was to determine the effect of soil applications of hydrogen peroxide solutions on plant growth and flowering. Nasturtium (Tropaeolum maju...

  9. Molecular Association and Structure of Hydrogen Peroxide.

    Giguere, Paul A.

    1983-01-01

    The statement is sometimes made in textbooks that liquid hydrogen peroxide is more strongly associated than water, evidenced by its higher boiling point and greater heat of vaporization. Discusses these and an additional factor (the nearly double molecular mass of the peroxide), focusing on hydrogen bonds and structure of the molecule. (JN)

  10. 7 CFR 58.431 - Hydrogen peroxide.

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Hydrogen peroxide. 58.431 Section 58.431 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Material § 58.431 Hydrogen peroxide. The solution shall comply with the specification of the...

  11. Vapor Hydrogen Peroxide Sterilization Certification

    Chen, Fei; Chung, Shirley; Barengoltz, Jack

    For interplanetary missions landing on a planet of potential biological interest, United States NASA planetary protection currently requires that the flight system must be assembled, tested and ultimately launched with the intent of minimizing the bioload taken to and deposited on the planet. Currently the only NASA approved microbial reduction method is dry heat sterilization process. However, with utilization of such elements as highly sophisticated electronics and sensors in modern spacecraft, this process presents significant materials challenges and is thus an undesirable bioburden reduction method to design engineers. The objective of this work is to introduce vapor hydrogen peroxide (VHP) as an alternative to dry heat microbial reduction to meet planetary protection requirements. The VHP sterilization technology is widely used by the medical industry, but high doses of VHP may degrade the performance of flight hardware, or compromise material compatibility. The goal of our study is determine the minimum VHP process conditions for PP acceptable microbial reduction levels. A series of experiments were conducted using Geobacillus stearothermophilus to determine VHP process parameters that provided significant reductions in spore viability while allowing survival of sufficient spores for statistically significant enumeration. In addition to the obvious process parameters -hydrogen peroxide concentration, number of pulses, and exposure duration -the investigation also considered the possible effect of environmental pa-rameters. Temperature, relative humidity, and material substrate effects on lethality were also studied. Based on the results, a most conservative D value was recommended. This recom-mended D value was also validated using VHP "hardy" strains that were isolated from clean-rooms and environmental populations collected from spacecraft relevant areas. The efficiency of VHP at ambient condition as well as VHP material compatibility will also be

  12. Hydrogen peroxide as a sustainable energy carrier: Electrocatalytic production of hydrogen peroxide and the fuel cell

    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.

  13. Mechanisms of wet oxidation by hydrogen peroxide

    A research programme is currently under way at BNL and MEL to investigate the possible use of Hydrogen Peroxide with metal ion catalysts as a wet oxidation treatment system for CEGB organic radioactive wastes. The published literature relating to the kinetics and mechanism of oxidation and decomposition reactions of hydrogen peroxide is reviewed and the links with practical waste management by wet oxidation are examined. Alternative wet oxidation systems are described and the similarities to the CEGB research effort are noted. (author)

  14. Electrolytic process for producing hydrogen peroxide

    An electrolytic process for producing hydrogen peroxide in an aqueous alkaline solution includes simultaneously passing an aqueous alkaline electrolyte and oxygen through a fluid permeable conductive cathode comprising reticulated vitreous carbon foam, separating the fluid permeable conductive cathode from an anode by a barrier and connecting the fluid permeable conductive electrode and the anode with an external power source to cause generation of hydrogen peroxide ion within the aqueous alkaline solution

  15. Troilite oxidation by hydrogen peroxide

    The kinetics and mechanism of troilite oxidation by H2O2 was studied at temperatures of 25 and 45 deg. C. Solutions within the range 0.1-0.85 mol L-1 H2O2 in HClO4 (0.01-0.1 mol L-1) were used as dissolution media. The experimental amount of dissolved iron was plotted versus t(n), with n ranging from 0.25 to 1.55. The theoretical interpretation of this dependence suggests that the troilite oxidation involves several processes: acidic troilite dissolution, FeS + 2H+ ↔ /SH2/ + /Fe2+/, where /SH2/ and /Fe2+/ are H2S and Fe2+ at troilite/sulfur rich layer (SRL) interface; /Fe2+/ migration into solution across SRL, and its rapid oxidation by hydrogen peroxide into ferric iron, 2Fe2+ + H2O2 + 2H+ 2Fe3+ + 2H2O; oxidation of /SH2/ sites to elemental sulfur, a process that contributes to sulfur enrichment of troilite surface, /SH2/ + 2Fe3+ S + 2Fe2+ + 2H+; oxidation of elemental sulfur to sulfate, a sulfur-consuming process, S + 3H2O2 = SO42- + 2H2O + 2H+. Both experimental results and theoretical considerations illustrate the importance of temperature, pH, and [H2O2] for the kinetics and mechanisms of troilite oxidation. The amounts of dissolved iron strongly increase with temperature and [H+], whereas an increase of H2O2 concentration seems to reduce the troilite oxidation. The reaction orders with respect to [H+] are variable, pointing out notable modifications of reaction mechanism with experimental conditions. The estimated value Ea 25.4 ± 0.9 kJ mol-1 ([H2O2] = 0.4 mol L-1 and pH 1) points to dissolution kinetics controlled by a mix regime of surface reaction and diffusion. (authors)

  16. ENA of heterocyclic hydrocarbons by adding hydrogen peroxide in groundwater circulation wells - a field-based study on a large physical model scale

    Heterocyclic Hydrocarbons (NSO-HET) are ingredients of tar oil, commonly found down-gradient of former gasworks sites. Typical NSO-HET are benzofurans, methyl-benzofurans, methylquinoline, acridine or carbazole. During investigations of MNA (monitored natural attenuation) remediation strategies, it was found that most NSO-HET are highly mobile due to their high water solubility and low biodegradation rates. In addition, some were found to be highly toxic and carcinogenic. In particular under anaerobic conditions, NSO-HET biodegradation rates are low. However, aerobic biological degradation was found to be effective. Based on the extension and contaminant distribution of the plume (∼ 800 m long) down-gradient of a former gasworks 'Testfeld Sued' (TFS) in Southern Germany, the most applicable technology for enhancing the natural degradation of PAH, BTEX and NSO-HET was selected and tested under controlled conditions in a large physical model (Large Flume of VEGAS). The investigations focused on a technology for a homogeneous infiltration of electron acceptor solutions such as oxygen and hydrogen peroxide to provide the bacteria with molecular oxygen. An initial infiltration of oxygen (air-saturated water) during the adaptation of microorganism to aerobic biodegradation was followed by a time-limited addition of hydrogen peroxide to achieve an oxygen concentration up to 23 mg/L in the model aquifer. An almost complete degradation of NSO-HET was found. On the basis of numerical simulations and lab experiments, it was found that natural dispersion will not lead to a wide-ranging homogeneous distribution and mixing of the oxygen in the aquifer. The Groundwater Circulation Wells technology (GCW) can be applied to achieve a maximum mixing of the electron acceptor solution with the groundwater. A spherical groundwater circulation is induced by means of ex- and infiltration ports in vertical wells. Infiltration and ex-filtration ports are located in hydraulically separated

  17. [Hydrogen peroxide in artificial photosynthesizing systems].

    Lobanov, A V; Komissarov, G G

    2014-01-01

    From the point of view of the concepts of hydrogen peroxide as a source of photosynthetic oxygen (hydrogen) coordination and photochemical properties of chlorophyll and its aggregates towards hydrogen peroxide were considered. The binding energy of H2O and H2O2 with chlorophyll and chlorophyllide depending on their form (monomers, dimers and trimers) was estimated by quantum chemical calculations. It is shown that at an increase of the degree of the pigment aggregation binding energy of H2O2 was more than the energy of H2O. Analysis of experimental results of the photochemical decomposition of hydrogen peroxide using chlorophyll was carried out. Estimates of the thermodynamic parameters (deltaG degrees and deltaH degrees) of the formation of organic compounds from CO2 with water and hydrogen peroxide were compared. The interaction of CO2 with H2O2 requires much less energy consumption than with water for all considered cases. The formation of organic products (formaldehyde, alcohols, carboxylic and carbonylic compounds) and simultaneous production of O2 under the influence of visible light in the systems of inorganic carbon--hydrogen peroxide--chlorophyll (phthalocyanine) is detected by GC/MS method, FTIR spectroscopy, and chemical analysis. PMID:25702472

  18. Troilite oxidation by hydrogen peroxide

    Chirita, Paul [Department of Inorganic and Analytical Chemistry, University of Craiova, Calea Bucuresti BB 107, Craiova 200512 (Romania); Descostes, Michael [CEA, DEN/DANS/DPC/SECR/Laboratory of Radionuclides Migration Measurements and Modelling, F-91191 Gif-sur-Yvette (France)

    2006-07-01

    The kinetics and mechanism of troilite oxidation by H{sub 2}O{sub 2} was studied at temperatures of 25 and 45 deg. C. Solutions within the range 0.1-0.85 mol L{sup -1} H{sub 2}O{sub 2} in HClO{sub 4} (0.01-0.1 mol L{sup -1}) were used as dissolution media. The experimental amount of dissolved iron was plotted versus t(n), with n ranging from 0.25 to 1.55. The theoretical interpretation of this dependence suggests that the troilite oxidation involves several processes: acidic troilite dissolution, FeS + 2H{sup +} {r_reversible} /SH{sub 2}/ + /Fe{sup 2+}/, where /SH{sub 2}/ and /Fe{sup 2+}/ are H{sub 2}S and Fe{sup 2+} at troilite/sulfur rich layer (SRL) interface; /Fe{sup 2+}/ migration into solution across SRL, and its rapid oxidation by hydrogen peroxide into ferric iron, 2Fe{sup 2+} + H{sub 2}O{sub 2} + 2H{sup +} 2Fe{sup 3+} + 2H{sub 2}O; oxidation of /SH{sub 2}/ sites to elemental sulfur, a process that contributes to sulfur enrichment of troilite surface, /SH{sub 2}/ + 2Fe{sup 3+} S + 2Fe{sup 2+} + 2H{sup +}; oxidation of elemental sulfur to sulfate, a sulfur-consuming process, S + 3H{sub 2}O{sub 2} = SO{sub 4}{sup 2-} + 2H{sub 2}O + 2H{sup +}. Both experimental results and theoretical considerations illustrate the importance of temperature, pH, and [H{sub 2}O{sub 2}] for the kinetics and mechanisms of troilite oxidation. The amounts of dissolved iron strongly increase with temperature and [H{sup +}], whereas an increase of H{sub 2}O{sub 2} concentration seems to reduce the troilite oxidation. The reaction orders with respect to [H{sup +}] are variable, pointing out notable modifications of reaction mechanism with experimental conditions. The estimated value E{sub a} 25.4 {+-} 0.9 kJ mol{sup -1} ([H{sub 2}O{sub 2}] = 0.4 mol L{sup -1} and pH 1) points to dissolution kinetics controlled by a mix regime of surface reaction and diffusion. (authors)

  19. Treatment of nanofiltration concentrates of mature landfill leachate by a coupled process of coagulation and internal micro-electrolysis adding hydrogen peroxide.

    Huang, Jingang; Chen, Jianjun; Xie, Zhengmiao; Xu, Xiaojun

    2015-01-01

    In this study, a coupled process of coagulation and aerated internal micro-electrolysis (IME) with the in situ addition of hydrogen peroxide (H2O2) was investigated for the treatment of nanofiltration (NF) concentrate from mature landfill leachate. The acceptable operating conditions were determined as follows: initial pH 4, polymeric aluminium chloride dosage of 525 mg-Al2O3/L in the coagulation process, H2O2 dosage of 0.75 mM and an hydraulic retention time of 2 h in an aerated IME reactor. As a result, the removal efficiencies for chemical oxygen demand (COD), total organic carbon, UV254 and colour were 79.2%, 79.6%, 81.8% and 90.8%, respectively. In addition, the ratio of biochemical oxygen demand (BOD5)/COD in the final effluent increased from 0.03 to 0.31, and that of E2/E4 from 12.4 to 38.5, respectively. The results indicate that the combined process is an effective and economical way to remove organic matters and to improve the biodegradability of the NF concentrate. Coagulation process reduces the adverse impact of high-molecular-weight organic matters such as humic acids, on the aerated IME process. A proper addition of H2O2 in the aerated IME can promote the corrosion of solid iron (Fe2+/Fe3+) and cause a likely domino effect in the enhancement of removal efficiencies. PMID:25270868

  20. Bactericidal and cytotoxic effects of hypothiocyanite-hydrogen peroxide mixtures.

    Carlsson, J.; Edlund, M B; Hänström, L.

    1984-01-01

    Lactoperoxidase catalyzes the oxidation of thiocyanate by hydrogen peroxide into hypothiocyanite, a reaction which can protect bacterial and mammalian cells from killing by hydrogen peroxide. The present study demonstrates, however, that lactoperoxidase in the presence of thiocyanate can actually potentiate the bactericidal and cytotoxic effects of hydrogen peroxide under specific conditions, such as when hydrogen peroxide is present in the reaction mixtures in excess of thiocyanate. The toxi...

  1. Hydrogen peroxide excretion by oral streptococci and effect of lactoperoxidase-thiocyanate-hydrogen peroxide.

    Carlsson, J.; Y. Iwami; Yamada, T.

    1983-01-01

    Approved type strains of Streptococcus sanguis, S. mitis, S. mutans, and S. salivarius were grown under aerobic and anaerobic conditions. The rate of hydrogen peroxide excretion, oxygen uptake, and acid production from glucose by washed-cell suspensions of these strains were studied, and the levels of enzymes in cell-free extracts which reduced oxygen, hydrogen peroxide, or hypothiocyanite (OSCN-) in the presence of NADH or NADPH were assayed. The effects of lactoperoxidase-thiocyanate-hydrog...

  2. Impact of hydrogen peroxide as a soil amendment on nasturtiums

    Hydrogen peroxide, H2O2, is a highly reactive oxidizing agent naturally occurring in plants and animals. Plants produce hydrogen peroxide to destroy either their infected plant cells or the pathogens within their cells. Hydrogen peroxide also acts as a stress signal to plants. It is approved for c...

  3. Experimental investigation of hydrogen peroxide RF plasmas

    Barni, R.; Decina, A.; Zanini, S.; D'Orazio, A.; Riccardi, C.

    2016-04-01

    This work reports a detailed experimental study of the plasma properties in low pressure RF discharges in hydrogen peroxide and a comparison with argon under the same operating conditions. H2O2 plasmas have been proposed for sterilization purposes. Electrical properties of the discharge were shown to be similar, as for the RF and DC voltages of the driving electrode. Bulk plasma volume remains stable, concentrated in an almost cylindrical region between the two facing electrodes. It was found that the electron temperature is almost uniform across the plasma and independent of the power level. This is higher than in argon discharges: T e  =  4.6  ±  0.9 eV versus T e  =  3.3  ±  1.1 eV. The plasma density increases almost linearly with the power level and a substantial negative ion component has been ruled out in hydrogen peroxide. Dissociation in the plasma gas phase was revealed by atomic hydrogen and hydroxyl radical emission in the discharge spectra. Emission from hydroxyl and atomic oxygen demonstrates that oxidizing radicals are produced by hydrogen peroxide discharges, revealing its usefulness for plasma processing other than sterilization, for instance to increase polymer film surface energy. On the other hand, argon could be considered as a candidate for the sterilization purposes due to the intense production of UV radiation.

  4. Hydrogen Peroxide Metabolism in Yeasts

    Verduyn, C; Giuseppin, M L; Scheffers, W A; van Dijken, J P

    1988-01-01

    A catalase-negative mutant of the yeast Hansenula polymorpha consumed methanol in the presence of glucose when the organism was grown in carbon-limited chemostat cultures. The organism was apparently able to decompose the H2O2 generated in the oxidation of methanol by alcohol oxidase. Not only H2O2 generated intracellularly but also H2O2 added extracellularly was effectively destroyed by the catalase-negative mutant. From the rate of H2O2 consumption during growth in chemostat cultures on mix...

  5. Functionalized Palladium Nanoparticles for Hydrogen Peroxide Biosensor

    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.

  6. New hydrogen peroxide bioburden reduction specification

    Kminek, Gerhard; Conley, Catharine

    2012-07-01

    The presentation will detail approved Planetary Protection specifications for the process of Vapor Hydrogen Peroxide (VHP) bioburden reduction for spacecraft components and subsystems. Outlined will be the research and studies on which the specifications were based. The research, funded by ESA and NASA/JPL, was conducted over a period of two years and was followed by limited material compatibility studies to assess the feasibility of this bioburden reduction modality for spacecraft.

  7. Hydrogen peroxide production in capillary underwater discharges

    De Baerdemaeker, F.; Šimek, Milan; Leys, C.

    2007-01-01

    Roč. 40, č. 9 (2007), s. 2801-2809. ISSN 0022-3727 R&D Projects: GA AV ČR IAA1043403 Institutional research plan: CEZ:AV0Z20430508 Keywords : water breakdown * capillary * AC discharge * conductive liquid * hydrogen peroxide formation * initial rate * energy yield Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.200, year: 2007

  8. Hydrogen peroxide production in capillary underwater discharges

    De Baerdemaeker, F.; Šimek, Milan; Člupek, Martin; Lukeš, Petr; Leys, C.

    2006-01-01

    Roč. 56, suppl. B (2006), s. 1132-1139. ISSN 0011-4626. [Symposium on Plasma Physics and Technology/22nd./. Praha, 26.6.2006-29.6.2006] R&D Projects: GA AV ČR(CZ) IAA1043403 Institutional research plan: CEZ:AV0Z20430508 Keywords : water * capillary * AC discharge * hydrogen peroxide formation * initial rate Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.568, year: 2006

  9. Hydrogen Peroxide Propulsion for Smaller Satellites

    Whitehead, John

    1998-01-01

    As satellite designs shrink, providing maneuvering and control capability falls outside the realm of available propulsion technology. While cold gas has been used on the smallest satellites, hydrogen peroxide propellant is suggested as the next step in performance and cost before hydrazine. Minimal toxicity and a small scale enable bench top propellant preparation and development testing. Progress toward low-cost thrusters and self-pressurizing tank systems is described.

  10. THE EFFECT OF TRANSITION METAL IONS-MANGANESE ON HYDROGEN PEROXIDE BLEACHING

    ShuhuiYang; YumengZhao; BaokuWen; YonghaoNi

    2004-01-01

    In this investigation, the catalytic activities of Mn(II),Mn(III) and Mn(IV) towards decomposing hydrogenperoxide were compared. Among Mn (II), Mn (III)and Mn (IV), Mn (II) is not catalytically active indecomposing hydrogen peroxide. However, both Mn(113) and Mn (IV) are, and Mn (III) has a strongereffect than Mn(IV).In addition, we also studied the practical methods todecrease the Mn-induced decomposition of hydrogenperoxide. The results showed that sodium silicate andmagnesium sulfite in combination can effectivelydecrease the decomposition of hydrogen peroxide.The optimum dosage of sodium silicate was about0.5% (on solution). Adding chelants such as DTPAor EDTA simultaneously with stabilizers candecrease hydrogen peroxide decomposition. For Mn(IV), the EDTA is more effective than DTPA.Adding sodium thiosulfate simultaneously withmagnesium sulfate, sodium silicate and DTPA toalkaline peroxide solution can result in more residualhydrogen peroxide, and a higher pulp brightness.

  11. Hydrogen peroxide decomposition kinetics in aquaculture water

    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...... 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...... application in RAS by addressing disinfection demand and identify efficient and safe water treatment routines....

  12. Quantification of peroxide ion passage in dentin, enamel, and cementum after internal bleaching with hydrogen peroxide.

    Palo, R M; Bonetti-Filho, I; Valera, M C; Camargo, C H R; Camargo, Sea; Moura-Netto, C; Pameijer, C

    2012-01-01

    The aim of this study was to evaluate the amount of peroxide passage from the pulp chamber to the external enamel surface during the internal bleaching technique. Fifty bovine teeth were sectioned transversally 5 mm below the cemento-enamel junction (CEJ), and the remaining part of the root was sealed with a 2-mm layer of glass ionomer cement. The external surface of the samples was coated with nail varnish, with the exception of standardized circular areas (6-mm diameter) located on the enamel, exposed dentin, or cementum surface of the tooth. The teeth were divided into three experimental groups according to exposed areas close to the CEJ and into two control groups (n=10/group), as follows: GE, enamel exposure area; GC, cementum exposed area; GD, dentin exposed area; Negative control, no presence of internal bleaching agent and uncoated surface; and Positive control, pulp chamber filled with bleaching agent and external surface totally coated with nail varnish. The pulp chamber was filled with 35% hydrogen peroxide (Opalescence Endo, Ultradent). Each sample was placed inside of individual flasks with 1000 μL of acetate buffer solution, 2 M (pH 4.5). After seven days, the buffer solution was transferred to a glass tube, in which 100 μL of leuco-crystal violet and 50 μL of horseradish peroxidase were added, producing a blue solution. The optical density of the blue solution was determined by spectrophotometer and converted into microgram equivalents of hydrogen peroxide. Data were submitted to Kruskal-Wallis and Dunn-Bonferroni tests (α=0.05). All experimental groups presented passage of peroxide to the external surface that was statistically different from that observed in the control groups. It was verified that the passage of peroxide was higher in GD than in GE (ppermeable than were the dentin and enamel surfaces. PMID:22621165

  13. Hydrogen peroxide leaching of uranium in carbonate solutions

    The kinetics of UO2 dissolution in ammoniacal carbonate solutions were investigated with hydrogen peroxide as an oxidant. The effects of hydrogen peroxide concentration, total carbonate concentration and pH were studied. For similar conditions, the rate of dissolution was considerably faster with hydrogen peroxide than with oxygen. The reaction was found to be of 0.5 order with respect to both hydrogen peroxide and total carbonate concentrations. At pH values below approximately 10, the rate was relatively insensitive to pH. These results are consistent with an electrochemical surface reaction similar to that developed for the oxygen-leaching system. Electrochemical interpretation adequately explain the enhanced rate of dissolution observed for hydrogen peroxide leaching. The decomposition of hydrogen peroxide in alkaline solutions is discussed. Surface-electrode potentials are used to explain the catalytic activity of various solids. Hydrogen peroxide was found to decompose rapidly in the presence of freshly precipitated ferric hydroxide. The effect of pH on the rate of hydrogen peroxide decomposition was investigated in the pH range 4.3 to 11.2. Problems associated with the use of hydrogen peroxide in the in-situ leaching of uranium are considered. (author)

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

    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.

  15. HE EFFECT OF TRANSITION METAL IONS-IRON ON HYDROGEN PEROXIDE BLEACHING

    Yumeng Zhao; Shuhui Yang; Liang Sheng; Yonghao Ni

    2004-01-01

    Hydrogen peroxide bleaching has been extensively used in high-yield pulp bleaching. Unfortunately,hydrogen peroxide can be decomposed under alkaline condition, especially when transition metal ions exit. Experiments show that the valence of transition metal ion is also responsible for the decomposition of hydrogen peroxide.Iron ions are present in two oxidation states, Fe2+ and Fe3+. They are both catalytically active to hydrogen peroxide decomposition. Because Fe3+ is brown, it can affect the brightness of pulp directly, it can also combine with phenol, forming complexes which not only are stable structures and are difficult to be removed from pulp, but also significantly affect the brightness of pulp because of their color.Sodium silicate and magnesium sulfate, when used together, can greatly decrease hydrogen peroxide decomposition. The optimum dosage of sodium silicate is about 0.1% (on solution) for Fe2+ and 0.25% (on solution) for Fe3+. Adding chelants such as DTPA or EDTA with stabilizers simultaneously can obviously improve pulp brightness. For iron ions, the chelate effect of DTPA is better than that of EDTA.Under acidic conditions, sodium hyposulfite and cellulose can reduce Fe3+ to Fe2+ effectively, and pulp brightness is improved greatly. Adding sodium thiosulfate simultaneously with magnesium sulfate,sodium silicate, and DTPA to alkaline peroxide solution can result in higher brightness of pulp.pH is a key parameter during hydrogen peroxide bleaching, the optimum pH value should be 10.5-12.

  16. THE EFFECT OF TRANSITION METAL IONS-MANGANESE ON HYDROGEN PEROXIDE BLEACHING

    Shuhui Yang; Yumeng Zhao; Baoku Wen; Yonghao Ni

    2004-01-01

    In this investigation, the catalytic activities of Mn(Ⅱ),Mn(Ⅲ) and Mn(Ⅳ) towards decomposing hydrogen peroxide were compared. Among Mn (Ⅱ), Mn (Ⅲ)and Mn (Ⅳ), Mn (Ⅱ) is not catalytically active in decomposing hydrogen peroxide. However, both Mn (Ⅲ) and Mn (Ⅳ) are, and Mn (Ⅲ) has a stronger effect than Mn(Ⅳ).In addition, we also studied the practical methods to decrease the Mn-induced decomposition of hydrogen peroxide. The results showed that sodium silicate and magnesium sulfite in combination can effectively decrease the decomposition of hydrogen peroxide.The optimum dosage of sodium silicate was about 0.5% (on solution). Adding chelants such as DTPA or EDTA simultaneously with stabilizers can decrease hydrogen peroxide decomposition. For Mn (Ⅳ), the EDTA is more effective than DTPA.Adding sodium thiosulfate simultaneously with magnesium sulfate, sodium silicate and DTPA to alkaline peroxide solution can result in more residual hydrogen peroxide, and a higher pulp brightness.

  17. Simple, field portable colorimetric detection device for organic peroxides and hydrogen peroxide

    Pagoria, Philip F.; Mitchell, Alexander R.; Whipple, Richard E.; Carman, M. Leslie; Reynolds, John G.; Nunes, Peter; Shields, Sharon J.

    2010-11-09

    A simple and effective system for the colorimetric determination of organic peroxides and hydrogen peroxide. A peroxide pen utilizing a swipe material attached to a polyethylene tube contains two crushable vials. The two crushable vials contain a colorimetric reagent separated into dry ingredients and liquid ingredients. After swiping a suspected substance or surface the vials are broken, the reagent is mixed thoroughly and the reagent is allowed to wick into the swipe material. The presence of organic peroxides or hydrogen peroxide is confirmed by a deep blue color.

  18. MODIFIED OPAL:A NOVEL STABILIZER FOR HYDROGEN PEROXIDE BLEACHING OF PULPS

    Xueren Qian; Xianhui An; Wenbo Liu; Gang Yu; Zhanqian Song

    2004-01-01

    The possibility of modified opal as the stabilizer of hydrogen peroxide bleaching was investigated. The results showed that the modified opal in place of sodium silicate as the stabilizer of hydrogen peroxide bleaching is feasible. At the same dosage, above 3% ISO can be increased for both wheat straw pulp and deinked pulp. The stabilizing ability of the modified opal to hydrogen peroxide bleaching of pulp is improved markedly. It is favorable for bleaching to increase temperature and time within a permissive extent. The suitable process conditions are 10% of pulp consistency, 3% of hydrogen peroxide, 1.5% of sodium hydroxide, 3% of the modified opal, 70℃ and 60 min when the modified opal is used as the stabilizer of hydrogen peroxide bleaching. At these conditions, the brightness gain can reach about 16% ISO for wheat straw pulp. In addition, it is favorable for bleaching to add a little magnesium sulfate when the modified opal is used as the stabilizer of hydrogen peroxide bleaching, the brightness of pulp can increase I%ISO if0.05% of magnesium sulfate is added. The cost analysis indicated that the modified opal is superior to sodium silicate as the stabilizer of hydrogen peroxide bleaching in economical aspect and has further the potential of market development.

  19. Selective electrochemical generation of hydrogen peroxide from water oxidation

    Viswanathan, Venkatasubramanian; Hansen, Heine A.; 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 requir...

  20. Hydrogen Peroxide Storage in Small Sealed Tanks

    Whitehead, J.

    1999-10-20

    Unstabilized hydrogen peroxide of 85% concentration has been prepared in laboratory quantities for testing material compatibility and long term storage on a small scale. Vessels made of candidate tank and liner materials ranged in volume from 1 cc to 2540 cc. Numerous metals and plastics were tried at the smallest scales, while promising ones were used to fabricate larger vessels and liners. An aluminum alloy (6061-T6) performed poorly, including increasing homogeneous decay due to alloying elements entering solution. The decay rate in this high strength aluminum was greatly reduced by anodizing. Better results were obtained with polymers, particularly polyvinylidene fluoride. Data reported herein include ullage pressures as a function of time with changing decay rates, and contamination analysis results.

  1. Hydrogen peroxide mediates higher order chromatin degradation.

    Bai, H; Konat, G W

    2003-01-01

    Although a large body of evidence supports a causative link between oxidative stress and neurodegeneration, the mechanisms are still elusive. We have recently demonstrated that hydrogen peroxide (H(2)O(2)), the major mediator of oxidative stress triggers higher order chromatin degradation (HOCD), i.e. excision of chromatin loops at the matrix attachment regions (MARs). The present study was designed to determine the specificity of H(2)O(2) in respect to HOCD induction. Rat glioma C6 cells were exposed to H(2)O(2) and other oxidants, and the fragmentation of genomic DNA was assessed by field inversion gel electrophoresis (FIGE). S1 digestion before FIGE was used to detect single strand fragmentation. The exposure of C6 cells to H(2)O(2) induced a rapid and extensive HOCD. Thus, within 30 min, total chromatin was single strandedly digested into 50 kb fragments. Evident HOCD was elicited by H(2)O(2) at concentrations as low as 5 micro M. HOCD was mostly reversible during 4-8h following the removal of H(2)O(2) from the medium indicating an efficient relegation of the chromatin fragments. No HOCD was induced by H(2)O(2) in isolated nuclei indicating that HOCD-endonuclease is activated indirectly by cytoplasmic signal pathways triggered by H(2)O(2). The exposure of cells to a synthetic peroxide, i.e. tert-butyrylhydroperoxide (tBH) also induced HOCD, but to a lesser extent than H(2)O(2). Contrary to the peroxides, the exposure of cells to equitoxic concentration of hypochlorite and spermine NONOate, a nitric oxide generator, failed to induce rapid HOCD. These results indicate that rapid HOCD is not a result of oxidative stress per se, but is rather triggered by signaling cascades initiated specifically by H(2)O(2). Furthermore, the rapid and extensive HOCD was observed in several rat and human cell lines challenged with H(2)O(2), indicating that the process is not restricted to glial cells, but rather represents a general response of cells to H(2)O(2). PMID:12421592

  2. Inactivation of rabies virus by hydrogen peroxide.

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

    2016-02-01

    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. PMID:26731189

  3. Efficient Electrochemical Hydrogen Peroxide Generation in Water Project

    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...

  4. A Novel Fluorescent Reagent for Analysis of Hydrogen Peroxide

    董素英; 苏美红; 聂丽华; 马会民

    2003-01-01

    8-(4,6-Dichloro-1,3,5-trazinoxy)quinoline(DTQ) was evaluated as a new fluorescent reagent for determining hydrogen peroxide.It was found that the fluorescence intensity of DTQ in alkaline medium could be dramatically enhanced upon addition of H2O2.Based on this effect,a simple and selective method for the spectrofluorimetric determination of hydrogen peroxide was estabhlished.The relative standard deviation of the method was found to be 1.1?for 9 replicate determinations of a 4.6×10-6mol/L hydrogen peroxide solution.The linear range was 2.3×10-7-2.3×10-5mol/L with a detection limit of 2.2×10-8mol/L(S/N=3).The ,method was attempted to determine hydrogen peroxide in synthetic human serum samples with satisfactory results.

  5. Hydrogen peroxide- metals- chelating agents; interactions and analytical techniques

    Rämö, J.

    2003-01-01

    Abstract Information about interactions among metals, hydrogen peroxide and chelating agents is needed to develop environmental technology and the operating efficiency of modern elemental chlorine free and total chlorine free bleaching processes. The work presented here focused on the properties of metal chelates and corrosion of titanium in an alkaline hydrogen peroxide solution. A comparative study between three rapid analysis methods, ICP-AES, XRF and ISE, was performed in pulp matrix a...

  6. Natural manganese deposits as catalyst for decomposing hydrogen peroxide

    Knol, A.H.; K. Lekkerkerker-Teunissen; 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, often biological, treatment steps. A drinking water company in the western part of the Netherlands investigated decomposition of about 5.75 mg L−1 hydrogen peroxide in pre-...

  7. Localised hydrogen peroxide sensing for reproductive health

    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.

  8. Atmospheric hydrogen peroxide and methyl hydroperoxide in Yanbian, China

    Kim, Y.; Ji, B.; Lee, M.; Kim, K.; Lee, G.

    2003-04-01

    Hydrogen peroxide and organic peroxides are photochemical byproducts. They are referred as the indicator of oxidizing capacity of the atmosphere. Further, they are related with the production and removal of ozone in photochemistry. To better understand the photochemical processes in the troposphere, it is essential to know the correct concentration of hydroperoxides. Hydrogen peroxide and methyl Hydroperoxide were measured from 24 Aug to 3 Sep in Yanbian, China. Measurements were made for continuously during the whole course of the experiments. After collected in aqueous solution using continuous scrubbing coil, hydroperoxides were separated by HPLC, and then quantified by fluorescence produced using postcolumn enzyme derivatization. Collection and analysis were done automatically Average concentration of hydrogen peroxide and methyl hydroperoxide were 0.9ppbc and 1.6 ppb, respectively. In general, hydroperoxides showed typical diurnal variations with the maximum concentration during day. It was the first study of air pollution conducted in Yanbian, China. Detailed results will be presented in the meeting.

  9. Different Modes of Hydrogen Peroxide Action During Seed Germination

    Wojtyla, Łukasz; Lechowska, Katarzyna; Kubala, Szymon; Garnczarska, Małgorzata

    2016-01-01

    Hydrogen peroxide was initially recognized as a toxic molecule that causes damage at different levels of cell organization and thus losses in cell viability. From the 1990s, the role of hydrogen peroxide as a signaling molecule in plants has also been discussed. The beneficial role of H2O2 as a central hub integrating signaling network in response to biotic and abiotic stress and during developmental processes is now well established. Seed germination is the most pivotal phase of the plant life cycle, affecting plant growth and productivity. The function of hydrogen peroxide in seed germination and seed aging has been illustrated in numerous studies; however, the exact role of this molecule remains unknown. This review evaluates evidence that shows that H2O2 functions as a signaling molecule in seed physiology in accordance with the known biology and biochemistry of H2O2. The importance of crosstalk between hydrogen peroxide and a number of signaling molecules, including plant phytohormones such as abscisic acid, gibberellins, and ethylene, and reactive molecules such as nitric oxide and hydrogen sulfide acting on cell communication and signaling during seed germination, is highlighted. The current study also focuses on the detrimental effects of H2O2 on seed biology, i.e., seed aging that leads to a loss of germination efficiency. The dual nature of hydrogen peroxide as a toxic molecule on one hand and as a signal molecule on the other is made possible through the precise spatial and temporal control of its production and degradation. Levels of hydrogen peroxide in germinating seeds and young seedlings can be modulated via pre-sowing seed priming/conditioning. This rather simple method is shown to be a valuable tool for improving seed quality and for enhancing seed stress tolerance during post-priming germination. In this review, we outline how seed priming/conditioning affects the integrative role of hydrogen peroxide in seed germination and aging. PMID:26870076

  10. Hydrogen peroxide potentiates organophosphate toxicosis in chicks

    Banan K. Al-Baggou

    2011-11-01

    Full Text Available Objective: The purpose of the present study was to examine the effect of hydrogen peroxide(H2O2 on the acute toxicity of organophosphate insecticides dichlorvos and diazinon and their inhibitoryactions on plasma, brain and liver cholinesterase activities. Material and Methods: H2O2 was given indrinking water (0.5% v/v for 2 weeks in unsexed day old chicks, a regimen known to induce oxidativestress in this species. A control group received drinking tap water. All experiments were conducted onthe chicks at the age of 15 days after exposure to H2O2. The acute (24 h oral LD50 values of dichlorvosand diazinon in the insecticidal preparations as determined by the up-and-down method in the controlchicks were 9.4 and 15.6 mg/kg, respectively. Results: The poisoned chicks manifested signs ofcholinergic toxicosis within one hour after the dosing including salivation, lacrimation, gasping, frequentdefecation, drooping of wings, tremors, convulsions and recumbency. The acute (24 h oral LD50 valuesof dichlorvos and diazinon in chicks provided with H2O2 were reduced to 3.5 and 6.5 mg/kg, by 63 and58%, respectively when compared to respective control LD50 values. The intoxicated chicks also showedcholinergic signs of toxicosis as described above. Plasma, brain and liver cholinesterase activities of thechicks exposed to H2O2 were significantly lower than their respective control (H2O values by 25, 28 and27%, respectively. Oral dosing of chicks with dichlorvos at 3 mg/kg significantly inhibited cholinesteraseactivities in the plasma, brain and liver of both control (42-67% and H2O2-treated (15-59% chicks.Diazinon at 5 mg/kg, orally also inhibited cholinesterase activities in the plasma, brain and liver of bothcontrol (36-66% and H2O2-treated (15-30% chicks. In the H2O2 groups, dichlorvos inhibition of livercholinesterase activity and diazinon inhibition of liver and brain cholinesterase activities weresignificantly lesser than those of the respective values of

  11. Improvement of adventitious root formation in flax using hydrogen peroxide.

    Takáč, Tomáš; Obert, Bohuš; Rolčík, Jakub; Šamaj, Jozef

    2016-09-25

    Flax (Linum usitatissimum L.) is an important crop for the production of oil and fiber. In vitro manipulations of flax are used for genetic improvement and breeding while improvements in adventitious root formation are important for biotechnological programs focused on regeneration and vegetative propagation of genetically valuable plant material. Additionally, flax hypocotyl segments possess outstanding morphogenetic capacity, thus providing a useful model for the investigation of flax developmental processes. Here, we investigated the crosstalk between hydrogen peroxide and auxin with respect to reprogramming flax hypocotyl cells for root morphogenetic development. Exogenous auxin induced the robust formation of adventitious roots from flax hypocotyl segments while the addition of hydrogen peroxide further enhanced this process. The levels of endogenous auxin (indole-3-acetic acid; IAA) were positively correlated with increased root formation in response to exogenous auxin (1-Naphthaleneacetic acid; NAA). Histochemical staining of the hypocotyl segments revealed that hydrogen peroxide and peroxidase, but not superoxide, were positively correlated with root formation. Measurements of antioxidant enzyme activities showed that endogenous levels of hydrogen peroxide were controlled by peroxidases during root formation from hypocotyl segments. In conclusion, hydrogen peroxide positively affected flax adventitious root formation by regulating the endogenous auxin levels. Consequently, this agent can be applied to increase flax regeneration capacity for biotechnological purposes such as improved plant rooting. PMID:26921706

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

    Zonios, George; Dimou, Aikaterini; Galaris, Dimitrios

    2008-01-01

    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 H2O2 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.

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

    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 H2O2 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

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

    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.

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

    Hydrogen peroxide plus limestone fragments allows removal of organisms without corrosion of limestone and speleothem. - 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 Katerinska 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 3.77x10-3 and 1.81x10-3 mol m-2 h-1, respectively. In the 15% peroxide solution, the limestone and speleothem dissolution rates were one order of magnitude higher, 2.00x10-2 and 2.21x10-2 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

  16. Selective electrochemical generation of hydrogen peroxide from water oxidation

    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...

  17. Selective Electrochemical Generation of Hydrogen Peroxide from Water Oxidation.

    Viswanathan, Venkatasubramanian; Hansen, Heine A; Nørskov, Jens K

    2015-11-01

    Water is a life-giving source, fundamental to human existence, yet over a billion people lack access to clean drinking water. The 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 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 sufficiently weakly, such as SnO2, can activate hydrogen peroxide evolution. We present a rational design principle for the selectivity in electrochemical water oxidation and identify new material candidates that could perform H2O2 evolution selectively. PMID:26538037

  18. Electrochemical behaviour of platinum in hydrogen peroxide solution (1963)

    The relative stability of hydrogen peroxide in aqueous solution at 25 deg. C, allows its amperometric determination from the theory, using either its cathodic reduction or its anodic oxidation. The cathodic reduction yields a wave on a platinum electrode only when some oxygen is present in the solution. It cannot, therefore, be used for electrochemical determination. On the other hand, the anodic oxidation on platinum produces a wave which might be used. However, a passivation of platinum occurs at the same time. This passivation process is studied by means of potentio-kinetic, potentio-static, intensio-static curves and of pH measurements in the vicinity of the anode. A mechanism for passivation is presented, which takes into account the role of hydrogen peroxide as a reducing agent. This passivation rules out any analytical application of the oxidation reaction of hydrogen peroxide. (author)

  19. Modeling the oxidation of phenolic compounds by hydrogen peroxide photolysis.

    Zhang, Tianqi; Cheng, Long; Ma, Lin; Meng, Fanchao; Arnold, Robert G; Sáez, A Eduardo

    2016-10-01

    Hydrogen peroxide UV photolysis is among the most widely used advanced oxidation processes (AOPs) for the destruction of trace organics in waters destined for reuse. Previous kinetic models of hydrogen peroxide photolysis focus on the dynamics of hydroxyl radical production and consumption, as well as the reaction of the target organic with hydroxyl radicals. However, the rate of target destruction may also be affected by radical scavenging by reaction products. In this work, we build a predictive kinetic model for the destruction of p-cresol by hydrogen peroxide photolysis based on a complete reaction mechanism that includes reactions of intermediates with hydroxyl radicals. The results show that development of a predictive kinetic model to evaluate process performance requires consideration of the complete reaction mechanism, including reactions of intermediates with hydroxyl radicals. PMID:27448315

  20. Carbonate leaching of uranium and hydrogen peroxide stabilizer therefor

    In the carbonate leaching process for the solution mining of subterranean uranium containing formations in which an injection well is drilled and completed within the uranium formation; alkaline carbonate uranium leaching solution and sufficient hydrogen peroxide are injected through the injection wells into the formation whereby uranium values are produced from production wells, characterized by providing in the leaching solution a mixture of 1-hydroxyethylidene-1,1-diphosphonic acid and an alkali metal pyrophosphate in a weight ratio of from 1 to 10 to 10 to 1, the amount of said mixture being sufficient to inhibit decomposition of the hydrogen peroxide in said leaching solution

  1. Formation of hydrogen peroxide through ozonolysis of alkenes

    Bechara, J.; Becker, K.H. (Wuppertal Univ. (Gesamthochschule) (DE)); Brockmann, K.J.

    1991-07-01

    The gas phase reactions of ozone with several alkenes (including isoprene and some terpenes) are investigated for the formation of hydrogen peroxide (H202) under atmospheric conditions by means of a TDLAS. All alkenes produced hydrogen peroxide with a molar yield in the part per thousand range. Water vapour induced a significant increase (factor 3 to 14) in H202 yield, due to the reaction of water vapour with the Criegee biradical, the main intermediate in alkene ozonolysis. Reaction rate are reported, with respect to sulfur dioxide, for ethene, tetramethylethene and limonene. Forest air application is discussed.

  2. Hydrogen Peroxide Gas Generator Cycle with a Reciprocating Pump

    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.

  3. ON-SITE APPLICABILITY OF HYDROGEN PEROXIDE PRODUCING MICROBIAL ELECTROCHEMICAL CELLS COUPLED WITH UV IN WASTEWATER DISINFECTION STUDY

    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...

  4. On-site applicability of hydrogen peroxide producing microbial electrochemical cells (MECs) coupled with UV in wastewater disinfection study

    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...

  5. Applications of hydrogen peroxide in electrochemical technology

    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

  6. Quantifying intracellular hydrogen peroxide perturbations in terms of concentration

    Beijing K. Huang

    2014-01-01

    Full Text Available Molecular level, mechanistic understanding of the roles of reactive oxygen species (ROS in a variety of pathological conditions is hindered by the difficulties associated with determining the concentration of various ROS species. Here, we present an approach that converts fold-change in the signal from an intracellular sensor of hydrogen peroxide into changes in absolute concentration. The method uses extracellular additions of peroxide and an improved biochemical measurement of the gradient between extracellular and intracellular peroxide concentrations to calibrate the intracellular sensor. By measuring peroxiredoxin activity, we found that this gradient is 650-fold rather than the 7–10-fold that is widely cited. The resulting calibration is important for understanding the mass-action kinetics of complex networks of redox reactions, and it enables meaningful characterization and comparison of outputs from endogenous peroxide generating tools and therapeutics across studies.

  7. THE EFFECT OF TRANSITION METAL IONS-IRON ON HYDROGEN PEROXIDE BLEACHING

    YumengZhao; ShuhuiYang; LiangSheng; YonghaoNi

    2004-01-01

    Hydrogen peroxide bleaching has been extensivelyused in high-yield pulp bleaching. Unfortunately,hydrogen peroxide can be decomposed underalkaline condition, especially when transition metalions exit. Experiments show that the valence oftransition metal ion is also responsible for thedecomposition of hydrogen peroxide.Iron ions are present in two oxidation states, Fe2+ andFe3+. They are both catalytically active to hydrogenperoxide decomposition. Because Fe3+ is brown, itcan affect the brightness of pulp directly, it can alsocombine with phenol, forming complexes which notonly are stable structures and are difficult to beremoved from pulp, but also significantly affect thebrightness of pulp because of their color.Sodium silicate and magnesium sulfate, when usedtogether, can greatly decrease hydrogen peroxidedecomposition. The optimum dosage of sodiumsilicate is about 0.1% (on solution) for Fe2~ and0.25% (on solution) for Fe3~. Adding chelants such asDTPA or EDTA with stabilizers simultaneously canobviously improve pulp brightness. For iron ions, thechelate effect of DTPA is better than that of EDTA.Under acidic conditions, sodium hyposulfite andcellulose can reduce Fe3+ to Fez+ effectively, and pulpbrightness is improved greatly. Adding sodiumthiosulfate simultaneously with magnesium sulfate,sodium silicate, and DTPA to alkaline peroxidesolution can result in higher brightness of pulp.pH is a key parameter during hydrogen peroxidebleaching, the optimum pH value should be 10.5-12.

  8. Precipitation of uranium concentrates by hydrogen peroxide

    An experimental study on the (UO4.xH2) uranyl peroxide precipitation from a uranium process strip solution is presented. The runs were performed in a batch reactor, in laboratory scale. The main objective was to assess the possibility of the peroxide route as an alternative to a conventional ammonium diuranate process. The chemical composition of process solution was obtained. The experiments were conducted according to a factorial design, aiming to evaluate the effects of initial pH, precipitation pH and H2O2/UO22+ ratio upon the process. The responses were measured in terms of the efficiency of U precipitation, the content of U in the precipitates and the distribution of impurities in the precipitates. The results indicated that the process works is satisfactory on the studied conditions and depending on conditions, it is possible to achieve levels of U precipitation efficiency greater than 99.9% in reaction times of 2 hours. The precipitates reach grades around 99% U3O8 after calcination (9000C) and impurities fall below the limit for penalties established by the ASTM and the Allied Chemical Standards. The precipitates are composed of large aggregates of crystals of 1-4 μm, are fast settling and filtering, and are free-flowing when dry. (Author)

  9. Selective Electrochemical Generation of Hydrogen Peroxide from Water Oxidation

    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...

  10. A PORTABLE MICROREACTOR SYSTEM TO SYNTHESIZE HYDROGEN PEROXIDE - PHASE I

    In the event that vehicles of buildings become contaminated by hazardous chemical or biological materials, a well-studied and effective decontaminant is hydrogen peroxide vapor (HPV).  Unfortunately, the current technology for generating HPV requires 35 weight percent hydro...

  11. Computer Data Processing of the Hydrogen Peroxide Decomposition Reaction

    余逸男; 胡良剑

    2003-01-01

    Two methods of computer data processing, linear fitting and nonlinear fitting, are applied to compute the rate constant for hydrogen peroxide decomposition reaction. The results indicate that not only the new methods work with no necessity to measure the final oxygen volume, but also the fitting errors decrease evidently.

  12. Hydrogen peroxide as a soil amendment for greenhouse nasturtium production (Tropaeolum majus L.)

    Hydrogen peroxide, H2O2, is a highly reactive oxidizing agent naturally occurring in plants and animals. Plants produce hydrogen peroxide to destroy either infected plant cells or the pathogens within a plant. Hydrogen peroxide also acts as a stress signal to plants. It is approved for the contro...

  13. 40 CFR 180.1197 - Hydrogen peroxide; exemption from the requirement of a tolerance.

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Hydrogen peroxide; exemption from the... Exemptions From Tolerances § 180.1197 Hydrogen peroxide; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of hydrogen peroxide in or on...

  14. Embryotoxic effects of eight organic peroxides and hydrogen peroxide on three-day chicken embryos

    Korhonen, A.; Hemminki, K.; Vainio, H.

    1984-02-01

    Nine peroxides used in rubber processing were tested for embryotoxicity in 3-day chicken embryos using the air chamber method. The potencies were expressed by the ED/sub 50/ for the total embryotoxic effect of the chemicals, including deaths and malformations, up to Day 14 of the incubation. The range of the ED/sub 50/'s was from 0.13 to 2.7 ..mu..moles per egg and the order of the potencies was as follows: cyclohexanoneperoxide > cumolhydroperoxide > ethylmethylketoneperoxide > dibenzoylperoxide > acetylacetoneperoxide > perbenzoic acid-tert-butylester > dicumylperoxide > dialauroylperoxide > hydrogen peroxide. All nine peroxides caused malformations at a moderate frequency. The maximum percentage of malformed embryos of the treated varied from the 16% of perbenzoic acid-tert-butylester to the 56% of dicumylperoxide. The high percentage caused by the latter could, however, result from slow diffusion of high lethal doses from the air chamber to the embryo.

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

    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 40oC in a continuous stirring tank reactor. The influence of the initial concentrations of iodine, iodate, hydrogen peroxide, H+ 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 [I2], [IO3-], [H2O2] and [H+]. A rate law has been determined for the two steps for molecular iodine. (author) figs., tabs., 22 refs

  16. Hydrogen embrittlement of 4340 steel due to condensation during vaporized hydrogen peroxide treatment

    Research highlights: → Exposure of low-alloy, high strength 4340 steel to water vapor with 500 or 1000 ppm hydrogen peroxide for 4.8 h does not lead to hydrogen embrittlement per ASTM 519E-06. → Exposure of low-alloy, high strength 4340 steel to 35 wt.% H2O2 in water for 4.8 h does not lead to hydrogen embrittlement per ASTM 519E-06. → Operation of vaporized hydrogen peroxide decontamination chambers at 1300 or 1600 ppm hydrogen peroxide concentration can lead to significant condensation with very high concentrations of H2O2 (50-75 wt.% H2O2) in the condensed liquid → Exposure of low-alloy, high strength 4340 steel to vaporized hydrogen peroxide treatments at 1300 or 1600 ppm hydrogen peroxide concentration for 4.8 h led to extensive condensation of high H2O2 concentration (∼64 wt.% H2O2) in the process chamber and hydrogen embrittlement of the steel per ASTM 519E-06. - Abstract: Hydrogen peroxide vapor has been proposed as a sterilant/decontaminant for usage in buildings and transportation vehicles including emergency vehicles, buses, trains and aircraft. Although the efficacy of the process has been demonstrated, questions regarding the compatibility of vaporized hydrogen peroxide treatments with the many diverse materials of construction have been raised. This paper presents results on the embrittlement of high strength AISI 4340 steel as a result of condensation of the vapor during exposure to vaporized hydrogen peroxide. Notched four point bending samples of AISI 4340 steel were tested using the standard test methods of ASTM F519-06 to quantify susceptibility to hydrogen embrittlement in this aggressive service environment. No embrittlement effects were observed for samples exposed to strictly vapor phase hydrogen peroxide for concentrations up to 1000 ppm H2O2 and exposure times of 4.8 h. Higher concentrations of 1300 and 1600 ppm H2O2 led to the condensation of the vapor throughout the process chamber and brittle fracture of samples. These results

  17. Cardiovascular responses to hydrogen peroxide into the nucleus tractus solitarius

    Cardoso, Leonardo Máximo; Colombari, Débora Simões Almeida; Menani, José V; Toney, Glenn M.; Chianca, Deoclécio Alves; Colombari, Eduardo

    2009-01-01

    The nucleus tractus solitarius (NTS), a major hindbrain area involved in cardiovascular regulation, receives primary afferent fibers from peripheral baroreceptors and chemoreceptors. Hydrogen peroxide (H2O2) is a relatively stable and diffusible reactive oxygen species (ROS), which acting centrally, may affect neural mechanisms. In the present study, we investigated effects of H2O2 alone or combined with the glutamatergic antagonist kynurenate into the NTS on mean arterial pressure (MAP) and ...

  18. Hydrogen peroxide removal with magnetically responsive Saccharomyces cerevisiae cells

    Šafařík, Ivo; Maděrová, Zdeňka; Šafaříková, Miroslava

    2008-01-01

    Roč. 56, - (2008), s. 7925-7928. ISSN 0021-8561 R&D Projects: GA MPO 2A-1TP1/094; GA MŠk OC 157 Institutional research plan: CEZ:AV0Z60870520 Keywords : magnetic alginate beads * catalase * magnetic separation * Saccharomyces cerevisiae cells * hydrogen peroxide Subject RIV: GM - Food Processing Impact factor: 2.562, year: 2008

  19. Petroleum Contaminated Soil Treatment Using Surfactant and Hydrogen Peroxide

    Ilza Lobo; Caryna Januario Correr; Carmen Luisa Barbosa Guedes; Otavio Jorge Grigoli Abi-Saab

    2010-01-01

    The process of washing soil with surfactants, sodium lauryl ether sulphate (LESS) and sodium lauryl sulphate (SDS) was combined with chemical oxidation using hydrogen peroxide, with a view to in situ remediation of clay soil contaminated with hydrocarbons oil. The evaluation of the efficiency of the procedure was the removal of polyaromatic hydrocarbons and the comparison of physical and chemical characteristics of contaminated soil and uncontaminated from the same region. The combination of ...

  20. Hydrogen peroxide propulsion for smaller satellites (SSC98-VIII-1)

    Whitehead, J C

    1998-07-13

    As satellite designs shrink, providing maneuvering and control capability falls outside the realm of available propulsion technology. While cold gas has been used on the smallest satellites, hydrogen peroxide propellant is suggested as the next step in performance and cost before hydrazine. Minimal toxicity and a small scale enable benchtop propellant preparation and development testing. Progress toward low-cost thrusters and self-pressurizing tank systems is described.

  1. The Effect Paraoxonase-1, Hydrogen Peroxide and Adiponectin

    Baghaiee B; Siahkuhian M; Hakimi M; Bolboli L; Ahmadi Dehrashid K

    2016-01-01

    Background and aims: Paraoxonase-1, Adiponectin and Hydrogen Peroxide are among indexes that are influenced by sedentary lifestyle; and it is possible that they’ll be effective on blood pressure. However, it is not clear the relationship between their changes with blood pressure as a result of participation in regular physical activity. So, the aim of this research was to investigate the effect of 12 weeks moderate aerobic exercise on relationship betw...

  2. Luminescent probes for detection and imaging of hydrogen peroxide

    The relevance of hydrogen peroxide (H2O2) in biological processes has been underestimated for a long time. In recent years, various reports showed that H2O2 not only acts as a cytotoxic compound appearing in the course of oxidative stress, but also functions as an important signaling molecule. Fluorescent probes (or indicators) and nanoparticles that respond selectively to hydrogen peroxide can be applied for intracellular measurements or in vivo imaging, and are superior to electrochemical methods, e. g. in terms of spatial resolution. In contrast to previous reviews that concentrated on the adoption of different probes for certain applications, this survey highlights the basic principles of different probes in terms of their chemical design, structures and functionalities. Thus, the probes are classified according to the underlying reaction mechanism: oxidation, hydrolysis, photoinduced electron transfer, and lanthanide complexation. Other assays are based on fluorescent proteins and nanoparticles, and chemi-or bioluminescent reagents. We confine this review to probes that display a more or less distinct selectivity to hydrogen peroxide. Indicators responding to reactive oxygen species (ROS) in general, or to particular other ROS, are not covered. Finally, we briefly discuss future trends and perspectives of these luminescent reporters in biomedical research and imaging. (author)

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

    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....

  4. Antibacterial activity of hydrogen peroxide and the lactoperoxidase-hydrogen peroxide-thiocyanate system against oral streptococci.

    Thomas, E L; Milligan, T W; Joyner, R E; Jefferson, M M

    1994-01-01

    In secreted fluids, the enzyme lactoperoxidase (LP) catalyzes the oxidation of thiocyanate ion (SCN-) by hydrogen peroxide (H2O2), producing the weak oxidizing agent hypothiocyanite (OSCN-), which has bacteriostatic activity. However, H2O2 has antibacterial activity in the absence of LP and thiocyanate (SCN-). Therefore, LP may increase antibacterial activity by using H2O2 to produce a more effective inhibitor of bacterial metabolism and growth, or LP may protect bacteria against the toxicity...

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

    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.

  6. Photochemical formation of hydrogen peroxide in surface and ground waters exposed to sunlight

    Cooper, W.J. (Florida International Univ., Miami); Zika, R.G.

    1983-05-13

    A rapid increase in the concentration of hydrogen peroxide was observed when samples of natural surface and ground water from various locations in the United States were exposed to sunlight. The hydrogen peroxide is photochemically generated from organic constitutents present in the water; humic materials are believed to be the primary agent producing the peroxide. Studies with superoxide dismutase suggest that the superoxide anion is the precursor of the peroxide.

  7. At-home vital bleaching: a comparison of hydrogen peroxide and carbamide peroxide treatments.

    Berga-Caballero, Amparo; Forner-Navarro, Leopoldo; Amengual-Lorenzo, José

    2006-01-01

    Tray bleaching of vital teeth performed at home by the patient under the dentist s supervision, whether alone or in combination with any of the in-office techniques, provides an interesting alternative to other methods employed in this type of dental treatment. This bleaching procedure applies low-concentration peroxides to the enamel by means of a custom-made mouth tray specifically designed for this purpose. The aim of this study is to examine and compare two commercially-available bleaching products, at equivalent concentrations, for use in this technique: VivaStyle (Vivadent) and FKD (Kin); the former is a 10% carbamide peroxide and the latter a 3.5% hydrogen peroxide formulation. It examines the parameters that must be monitored during the application of this type of procedure and presents 6 cases (3 treated with one of the above-mentioned products and the other 3 with the other), establishing the bleaching power of the products and the appearance and intensity of post-operatory hypersensitivity. The results obtained show that both products are effective for the purpose for which they were designed. In general, dental hypersensitivity was minimal. PMID:16388304

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

    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.

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

    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.

  10. The effect of hydrogen peroxide on polishing removal rate in CMP with various abrasives

    Manivannan, R.; Ramanathan, S.

    2009-01-01

    The effect of hydrogen peroxide in chemical mechanical planarization slurries for shallow trench isolation was investigated. The various abrasives used in this study were ceria, silica, alumina, zirconia, titania, silicon carbide, and silicon nitride. Hydrogen peroxide suppresses the polishing of silicon dioxide and silicon nitride surfaces by ceria abrasives. The polishing performances of other abrasives were either unaffected or enhanced slightly with the addition of hydrogen peroxide. The ceria abrasives were treated with hydrogen peroxide, and the polishing of the work surfaces with the treated abrasive shows that the inhibiting action of hydrogen peroxide is reversible. It was found that the effect of hydrogen peroxide as an additive is a strong function of the nature of the abrasive particle.

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

    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...

  12. Hydrogen Peroxide Produced by Oral Streptococci Induces Macrophage Cell Death

    Okahashi, Nobuo; Nakata, Masanobu; Sumitomo, Tomoko; Terao, Yutaka; Kawabata, Shigetada

    2013-01-01

    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 ...

  13. Petroleum Contaminated Soil Treatment Using Surfactant and Hydrogen Peroxide

    Ilza Lobo

    2010-12-01

    Full Text Available The process of washing soil with surfactants, sodium lauryl ether sulphate (LESS and sodium lauryl sulphate (SDS was combined with chemical oxidation using hydrogen peroxide, with a view to in situ remediation of clay soil contaminated with hydrocarbons oil. The evaluation of the efficiency of the procedure was the removal of polyaromatic hydrocarbons and the comparison of physical and chemical characteristics of contaminated soil and uncontaminated from the same region. The combination of these two techniques, soil washing and application of an oxidizing agent, presented as a process of effective remediation for soils contaminated with petroleum products in subtropical regions.

  14. Study on hydrogen peroxide generation by water surface discharge

    Yoshihara, K.; Ruma, Ruma.; Aoki, N.; Hosseini, S.H.R.; Sakugawa, T.; Akiyama, H.; Lukeš, Petr

    San Francisco : IEEE, 2013, s. 1-5. ISBN 978-1-4673-5167-6. - (IEEE. 101034). [IEEE Pulsed Power & Plasma Science Conference – PPPS 2013/19./. San Francisco (US), 16.07.2013-21.07.2013] Grant ostatní: Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100431203 Institutional support: RVO:61389021 Keywords : underwater discharge * water surface discharge * hydrogen peroxide Subject RIV: BL - Plasma and Gas Discharge Physics http://dx.doi.org/10.1109/PPC.2013.6627582

  15. Hydrogen peroxide-based propulsion and power systems.

    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.

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

    Barazesh, JM; Hennebel, T; Jasper, JT; Sedlak, DL

    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 con...

  17. Co-operative inhibitory effects of hydrogen peroxide and iodine against bacterial and yeast species

    Zubko, Elena I; Zubko, Mikhajlo K

    2013-01-01

    Background Hydrogen peroxide and iodine are powerful antimicrobials widely used as antiseptics and disinfectants. Their antimicrobial properties are known to be enhanced by combining them with other compounds. We studied co-operative inhibitory activities (synergism, additive effects and modes of growth inhibition) of hydrogen peroxide and iodine used concurrently against 3 bacterial and 16 yeast species. Results Synergistic or additive inhibitory effects were shown for hydrogen peroxide and ...

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

    Schoonen Martin A; Pak Aimee; Strongin Daniel; Cohn Corey A

    2005-01-01

    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 ...

  19. Hydrogenation of liquid natural rubber via diimide reduction in hydrazine hydrate/hydrogen peroxide system

    Liquid natural rubber (LNR) with molecular weight of lower than 105 and shorter polymeric chain than natural rubber was prepared. LNR was then hydrogenated via diimide reduction by oxidation of hydrazine hydrate with hydrogen peroxide. The unsaturated units of the rubber were converted into saturated hydrocarbon to strengthen the backbone of the polymer so it was able to resist thermal degradation. The results indicated that hydrogenation degree of the product (HLNR) could be extended to 91.2% conversion under appropriate conditions. The hydrogenated LNR (HLNR) was characterized using Fourier-Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy. The physical characteristics of HLNR were analyzed with Termogravimetric Analysis (TGA)

  20. Hydrogenation of liquid natural rubber via diimide reduction in hydrazine hydrate/hydrogen peroxide system

    Yusof, Muhammad Jefri Mohd; Jamaluddin, Naharullah; Abdullah, Ibrahim; Yusoff, Siti Fairus M. [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2015-09-25

    Liquid natural rubber (LNR) with molecular weight of lower than 10{sup 5} and shorter polymeric chain than natural rubber was prepared. LNR was then hydrogenated via diimide reduction by oxidation of hydrazine hydrate with hydrogen peroxide. The unsaturated units of the rubber were converted into saturated hydrocarbon to strengthen the backbone of the polymer so it was able to resist thermal degradation. The results indicated that hydrogenation degree of the product (HLNR) could be extended to 91.2% conversion under appropriate conditions. The hydrogenated LNR (HLNR) was characterized using Fourier-Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy. The physical characteristics of HLNR were analyzed with Termogravimetric Analysis (TGA)

  1. Antimicrobial mechanisms behind photodynamic effect in the presence of hydrogen peroxide

    Garcez, Aguinaldo Silva; Núñez, Silvia Cristina; Baptista, Mauricio S.; Daghastanli, Nasser Ali; Itri, Rosangela; Hamblin, Michael R.; Ribeiro, Martha Simões

    2010-01-01

    This study describes the use of methylene blue (MB) plus light (photodynamic inactivation, PDI) in the presence of hydrogen peroxide (H2O2) to kill Staphylococcus aureus, Escherichia coli, and Candida albicans. When H2O2 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 H2O2. It wa...

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

    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.

  3. Vapor hydrogen peroxide as alternative to dry heat microbial reduction

    Chung, S.; Kern, R.; Koukol, R.; Barengoltz, J.; Cash, H.

    The Jet Propulsion Laboratory in conjunction with the NASA Planetary Protection Officer has selected vapor phase hydrogen peroxide sterilization process for continued development as a NASA approved sterilization technique for spacecraft subsystems and systems The goal is to include this technique with appropriate specification in NPG8020 12C as a low temperature complementary technique to the dry heat sterilization process To meet microbial reduction requirements for all Mars in-situ life detection and sample return missions various planetary spacecraft subsystems will have to be exposed to a qualified sterilization process This process could be the elevated temperature dry heat sterilization process 115C for 40 hours which was used to sterilize the Viking lander spacecraft However with utilization of highly sophisticated electronics and sensors in modern spacecraft this process presents significant materials challenges and is thus undesirable to design engineers to achieve bioburden reduction The objective of this work is to introduce vapor hydrogen peroxide VHP as an alternative to dry heat microbial reduction to meet planetary protection requirements The VHP process is widely used by the medical industry to sterilize surgical instruments and biomedical devices but high doses of VHP may degrade the performance of flight hardware or compromise material compatibility Our goal for this study is to determine the minimum VHP process conditions for planetary protection acceptable microbial reduction levels A series of experiments were conducted to

  4. A low-volume microstructured optical fiber hydrogen peroxide sensor

    Schartner, E. P.; Murphy, D. F.; Ebendorff-Heidepriem, H.; Monro, T. M.

    2011-05-01

    The ability to measure the concentration of hydrogen peroxide (H2O2) in solution is critical for quality assessment and control in many disparate applications, including wine, aviation fuels and IVF. The objective of this research is to develop a rapid test for the hydrogen peroxide content that can be performed on very low volume samples (i.e. sub-μL) that is relatively independent of other products within the sample. For H2O2 detection we use suspended core optical fibers to achieve a high evanescent field interaction with the fluid of interest, without the constraint of limited interaction length that is generally inherent with nanowire structures. By filling the holes of the fiber with an analyte/fluorophore solution we seek to create a quick and effective sensor that should enable detection of desired species within liquid media. By choosing a fluorophore that reacts with our target species to produce an increase in fluorescence, we can correlate observed fluorescence intensity with the concentration of the target molecule.

  5. Formation of complexes of hydrogen peroxide molecules with DNA

    A possibility for hydrogen peroxide molecules to form stable complexes with atomic groups in the DNA backbone under the irradiation of the cell medium with high-energy ions has been studied. The energy of complexes is estimated, by taking the electrostatic and van der Waals interactions into account in the framework of the atom-atom potential function method. The interaction with metal counterions, which neutralize the surface charge of a macromolecule under natural conditions, is also taken into consideration. Stable configurations are determined for various complexes consisting of the atoms belonging to a DNA phosphate group, H2O2 and H2O molecules, and a Na+ metal ion. The complexes of hydrogen peroxide molecules with DNA phosphate groups and a counterions are shown to be not less stable than their complexes with water molecules. The attachment of an H2O2 molecule to a phosphate group of the double helix backbone can block the processes of DNA biological functioning and can deactivate the genetic mechanism of a cell

  6. Alkaline peroxide processing of low-enriched uranium targets for 99Mo production -- Decomposition of hydrogen peroxide

    The recent progress on the alkaline peroxide processing of low-enriched uranium targets for the production of 99Mo, a parent nuclide of the widely used medical isotope 99mTc, is reported. Kinetic studies were undertaken to investigate the decomposition of hydrogen peroxide in alkaline solution in contact with a uranium metal surface. It was found that the decomposition of hydrogen peroxide essentially follows the kinetic trend of uranium dissolution and can be classified into two regimes, depending on the hydroxide concentration. In the low-base regime (0.2 M), the rate of peroxide decomposition is independent of alkali concentration. When the acid/base equilibrium between H2O2 and O2H- is taken into account, the overall rate of hydrogen peroxide disappearance can be described as a 0.25th order reaction with respect to hydrogen peroxide concentration over NaOH concentrations ranging from 0.01 to 5 M. Empirical kinetics models are proposed and discussed

  7. Isolation of lactic acid bacteria exhibiting high scavenging activity for environmental hydrogen peroxide from fermented foods and its two scavenging enzymes for hydrogen peroxide.

    Watanabe, Akio; Kaneko, Chiaki; Hamada, Yasuhiro; Takeda, Kouji; Kimata, Shinya; Matsumoto, Takashi; Abe, Akira; Tanaka, Naoto; Okada, Sanae; Uchino, Masataka; Satoh, Junichi; Nakagawa, Junichi; Niimura, Youichi

    2016-01-01

    To obtain lactic acid bacteria that scavenge environmental hydrogen peroxide, we developed a specialized enrichment medium and successfully isolated Pediococcus pentosaceus Be1 strain from a fermented food. This strain showed vigorous environmental hydrogen peroxide scavenging activity over a wide range of hydrogen peroxide concentrations. High Mn-catalase and NADH peroxidase activities were found in the cell-free extract of the P. pentosaceus Be1 strain, and these two hydrogen peroxide scavenging enzymes were purified from the cell-free extract of the strain. Mn-catalase has been purified from several microorganisms by several researchers, and the NADH peroxidase was first purified from the original strain in this report. After cloning the genes of the Mn-catalase and the NADH peroxidase, the deduced amino acid sequences were compared with those of known related enzymes. PMID:27118075

  8. Investigation of Iron Powder, Hydrogen Peroxide and Iron Hydrogen Peroxide for Removal of Acid Yellow Powder 36 Dye from Aqueous Solutions

    Sardar, M.; A Sheikh Mohammadi; A.R Yazdanbakhsh; H Mohammad; M Zarabi

    2010-01-01

    "n "nBackgrounds and Objectives: A great part of organic compounds cause more pollution in natural  waters meet, are chemical dye material. Azo dyes have more usage in different industries. Azo dyes not only give undesirable dye to the water but also have mutation potential and carcinogenesis effects in human and cause the production of toxic substances in water environments.The purpose of this study is investigation of iron powder, hydrogen peroxide and iron powder-hydrogen peroxide pro...

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

    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...

  10. 40 CFR 415.90 - Applicability; description of the hydrogen peroxide production subcategory.

    2010-07-01

    ... 40 Protection of Environment 28 2010-07-01 2010-07-01 true Applicability; description of the hydrogen peroxide production subcategory. 415.90 Section 415.90 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Hydrogen Peroxide...

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

    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.

  12. Oxygen from Hydrogen Peroxide. A Safe Molar Volume-Molar Mass Experiment.

    Bedenbaugh, John H.; And Others

    1988-01-01

    Describes a molar volume-molar mass experiment for use in general chemistry laboratories. Gives background technical information, procedures for the titration of aqueous hydrogen peroxide with standard potassium permanganate and catalytic decomposition of hydrogen peroxide to produce oxygen, and a discussion of the results obtained in three…

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

    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.

  14. Production of zirconia powders by precipitation stripping with hydrogen peroxide

    This paper reports on an experimental study to obtain zirconia powders (ZrO2) from carboxylate zirconium solutions followed by hydrogen peroxide stripping and precipitation, that has been carried out. Zirconium carboxylate was prepared by solvent extraction from a chloride aqueous phase using magnesium carboxylate as organic phase. The variables examined in the precipitation were: Temp. 25-90 degrees C, H2O2 concentration: 0.3-5%, pH: 1-9. Organic/Aqueous ration (1/1) and reaction time (30 min.) were maintained at constant levels. The optimum results (98% of precipitation) were achieved at 25 degrees C, 5% H2O2 and pH 5. The precipitates were composed of large amorphous aggregates (2 with large variation of particle size (1-100 μm) was obtained

  15. Enzymatic generation of hydrogen peroxide shows promising antifouling effect

    Kristensen, J.B.; Olsen, Stefan Møller; Laursen, B.S.; Kragh, K.M.; Poulsen, C.H.; Besenbacher, F.; Meyer, R.L.

    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......, the reference coating without enzymes had 35-40 barnacles, 10% area coverage by diatoms and 15% area coverage by tunicates. The enzyme containing coating had only 6-12 barnacles, 10% area coverage by diatoms and no tunicates. The enzyme system had a performance similar to a copper-based commercial...

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

    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.

  17. Kinetics of dissolution of uranium metal foil by alkaline hydrogen peroxide

    To develop a new process for the production of 99Mo using low-enriched uranium targets, uranium dissolution in alkaline hydrogen peroxide was studied. Molybdenum-99 is a parent of the widely used medical isotope 99mTc. The rates of uranium dissolution in alkaline hydrogen peroxide solution were measured in an open, batch-type reactor and were found to be a 0.25th order reaction with respect to equilibrium hydrogen peroxide concentration. In general, uranium dissolution can be classified as a low-base (0.2 M hydroxide) process. In the low-base process, both the equilibrium hydrogen peroxide and the hydroxide concentrations affect the rate of uranium dissolution. In the high-base process, uranium dissolution is independent of alkali concentration; the presence of base affects only the equilibrium concentration of hydrogen peroxide. An empirical kinetics model is proposed and discussed

  18. Inactivation of possible micromycete food contaminants using the low-temperature plasma and hydrogen peroxide

    Čeřovský, M.; Khun, J.; Rusová, K.; Scholtz, V.; Soušková, H.

    2013-09-01

    The inhibition effect of hydrogen peroxide aerosol, low-temperature plasma and their combinations has been studied on several micromycetes spores. The low-temperature plasma was generated in corona discharges in the open air apparatus with hydrogen peroxide aerosol. Micromycete spores were inoculated on the surface of agar plates, exposed solely to the hydrogen peroxide aerosol, corona discharge or their combination. After incubation the diameter of inhibition zone was measured. The solely positive corona discharge exhibits no inactivation effect, the solely negative corona discharge and solely hydrogen peroxide aerosol exhibit the inactivation effect, however their combinations exhibit to be much more effective. Low-temperature plasma and hydrogen peroxide aerosol present a possible alternative method of microbial decontamination of food, food packages or other thermolabile materials.

  19. Development of hydrogen peroxide technique for bioburden reduction

    Rohatgi, N.; Schwartz, L.; Stabekis, P.; Barengoltz, J.

    In order to meet the National Aeronautics and Space Administration (NASA) Planetary Protection microbial reduction requirements for Mars in-situ life detection and sample return missions, entire planetary spacecraft (including planetary entry probes and planetary landing capsules) may have to be exposed to a qualified sterilization process. Presently, dry heat is the only NASA approved sterilization technique available for spacecraft application. However, with the increasing use of various man-made materials, highly sophisticated electronic circuit boards, and sensors in a modern spacecraft, compatibility issues may render this process unacceptable to design engineers and thus impractical to achieve terminal sterilization of the entire spacecraft. An alternative vapor phase hydrogen peroxide sterilization process, which is currently used in various industries, has been selected for further development. Strategic Technology Enterprises, Incorporated (STE), a subsidiary of STERIS Corporation, under a contract from the Jet Propulsion Laboratory (JPL) is developing systems and methodologies to decontaminate spacecraft using vaporized hydrogen peroxide (VHP) technology. The VHP technology provides an effective, rapid and low temperature means for inactivation of spores, mycobacteria, fungi, viruses and other microorganisms. The VHP application is a dry process affording excellent material compatibility with many of the components found in spacecraft such as polymers, paints and electronic systems. Furthermore, the VHP process has innocuous residuals as it decomposes to water vapor and oxygen. This paper will discuss the approach that is being used to develop this technique and will present lethality data that have been collected to establish deep vacuum VHP sterilization cycles. In addition, the application of this technique to meet planetary protection requirements will be addressed.

  20. Hydrogen Peroxide, Signaling in Disguise during Metal Phytotoxicity

    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

  1. Natural manganese deposits as catalyst for decomposing hydrogen peroxide

    A. H. Knol

    2015-01-01

    Full Text Available 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, often biological, treatment steps. A drinking water company in the western part of the Netherlands investigated decomposition of about 5.75 mg L−1 hydrogen peroxide in pre-treated Meuse river water with different catalysts on pilot scale. In down flow operation, the necessary reactor Empty Bed Contact Time (EBCT with the commonly used Granulated Activated Carbon (GAC and waste ground water filter gravel (MCFgw were the same with 149 s, corresponding with a conversion rate constant r of 0.021 s−1. The EBCT of the fine coating of ground water filter gravel (MC was significantly shorter with a little more than 10 s (r = 0.30 s−1. In up flow operation, with a flow rate of 20 m h−1, the EBCT of coating MC increased till about 100 s (r = 0.031 s−1, from which can be concluded, that the performance of this waste material is better compared with GAC, in both up and down flow operation. The necessary EBCT at average filtration rate of full scale dual layer filter material (MCFsw amounted to 209 s (r = 0.015 s−1. Regarding the average residence time in the full scale filters of 700 s, applying AOP in front of the filters could be an interesting alternative which makes a separate decomposition installation superfluous, on the condition that the primary functions of the filters are not affected.

  2. On the transferability of atomic contributions to the optical rotatory power of hydrogen peroxide, methyl hydroperoxide and dimethyl peroxide

    Sánchez, Marina; Alkorta, Ibon; Elguero, José;

    2014-01-01

    partitioned into atomic and group contributions. In the present work, we investigate the transferability of such individual contributions in a series of small, chiral molecules: hydrogen peroxide, methyl hydroperoxide and dimethyl peroxide. The isotropic atomic or group contributions have been evaluated for...... the hydrogen, oxygen and carbon atoms as well as for the methyl group at the level of time-dependent density functional theory with the B3LYP exchange-correlation functional employing a large Gaussian basis set. We find that the atomic or group contributions are not transferable among these three...

  3. Hydrogen peroxide generation in caco-2 cell culture medium by addition of phenolic compounds: effect of ascorbic acid.

    Roques, Sylvie Cambon; Landrault, Nicolas; Teissèdre, Pierre-Louis; Laurent, Caroline; Besançon, Pierre; Rouane, Jean-Max; Caporiccio, Bertrand

    2002-05-01

    Phenolic compounds have recently attracted special attention due to their beneficial health effects; their intestinal absorption and bioavailability need, therefore, to be investigated and Caco-2 cell culture model appeared as a promising tool. We have shown herein that the addition of a grape seed extract (GSE) to Dulbecco's modified Eagle's medium (DMEM) used for Caco-2 cell culture leads to a substantial loss of catechin, epicatechin and B2 and B3 dimers from GSE in the medium after 24 h and to a production of hydrogen peroxide (H2O2). When 1420 microM ascorbic acid is added to the DMEM, such H2O2 production was prevented. This hydrogen peroxide generation substantially involves inorganic salts from the DMEM. We recommend that ascorbic acid be added to circumvent such a risk. PMID:12150547

  4. SIMULTANEOUS REACTION AND LIQUID-LIQUID EXTRACTION IN THE HYDROGEN PEROXIDE PRODUCTION

    Shuxiang L(u); Li Wang; Zhentao Mi; Yaquan Wang

    2004-01-01

    The gas-liquid-liquid reactive extraction system for preparing hydrogen peroxide via anthraquinone was investigated. The oxidation reaction of hydrogenated working solution was combined with the extraction of hydrogen peroxide from working solution in a sieve plate column. The reaction of 2-ethylanthrahydroquionone with oxygen and the liquid-liquid extraction of hydrogen peroxide take place simultaneously. The oxygen was introduced with hydrogenated working solution through a nozzle in the bottom of the column, which worked as agitated air as well as oxidation reagent. The results showed the oxidation and extraction do not hamper each other, on the contrary, the presence of oxidation gas in the column can promote the transfer of hydrogen peroxide from organic phase to aqueous phase, thus the reaction efficiency and extraction efficiency increased with increasing gas superficial velocity. Furthermore, the oxidation efficiency is almost 100% and the extraction efficiency is higher than 90% in this process.

  5. SIMULTANEOUS REACTION AND LIQUID-LIQUID EXTRACTION IN THE HYDROGEN PEROXIDE PRODUCTION

    ShuxiangLǖ; LiWang; ZhentaoMi; YaquanWang

    2004-01-01

    The gas-liquid-liquid reactive extraction system for preparing hydrogen peroxide via anthraquinone was investigated. The oxidation reaction of hydrogenated working solution was combined with the extraction of hydrogen peroxide from working solution in a sieve plate column. The reaction of 2-ethylanthrahydroquionone with oxygen and the liquid-liquid extraction of hydrogen peroxide take place simultaneously. The oxygen was introduced with hydrogenated working solution through a nozzle in the bottom of the column, which worked as agitated air as well as oxidation reagent. The results showed the oxidation and extraction do not hamper each other, on the contrary, the presence of oxidation gas in the column can promote the transfer of hydrogen peroxide fi'om organic phase to aqueous phase, thus the reaction efficiency and extraction efficiency increased with increasing gas superficial velocity. Furthermore, the oxidation efficiency is almost 100% and the extraction efficiency is higher than 90% in this process.

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

    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. Hydrogen peroxide in exhaled breath condensate: A clinical study

    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.

  8. Photocatalytic Degradation of Pesticides in Natural Water: Effect of Hydrogen Peroxide

    Natividad Miguel

    2012-01-01

    Full Text Available The aim of this paper is to evaluate the effectiveness of photocatalytic treatment with titanium dioxide in the degradation of 44 organic pesticides analyzed systematically in the Ebro river basin (Spain. The effect of the addition of hydrogen peroxide in this treatment is studied, and a monitoring of effectiveness of photocatalytic processes is carried out by measurements of physical-chemical parameters of water. The application of photocatalytic treatment with 1 g L−1 of TiO2 during 30 minutes achieves an average degradation of the studied pesticides of 48%. Chlorine demand, toxicity, and dissolved organic carbon (DOC concentration of water are reduced. If hydrogen peroxide is added with a concentration of 10 mM, the average degradation of pesticides increases up to 57%, although chlorine demand and toxicity of water increase while DOC concentration remains unchanged with this treatment. The application of either photocatalytic treatments does not produce variations in the physical-chemical parameters of water, such as pH, conductivity, colour, dissolved oxygen, and hardness. The pesticides which are best degraded by photocatalytic treatments are parathion methyl, chlorpyrifos, α-endosulphan, 3,4-dichloroaniline, 4-isopropylaniline, and dicofol while the worst degraded are HCHs, endosulphan-sulphate, heptachlors epoxide, and 4,4′-dichlorobenzophenone.

  9. Treatment of four biorefractory contaminants in soils using catalyzed hydrogen peroxide

    The treatment of soil with pentachlorophenol, trifluralin, hexadecane, and dieldrin using catalyzed hydrogen peroxide [H2O and iron(II)] was investigated in a soil of low development with organic C ranging from 2,000 mg kg-1 to 16,000 mg kg-1. Soil treatment was conducted at pH 3 with 240 and 400 mg L-1 iron additions and 120,000 mg L-1 H2O2. Pentachlorophenol and trifluralin degradation rates decreased as a function of soil organic C content. However, soil organic C had no effect on the degradation rates of dieldrin and hexadecane. In addition, the four contaminant degraded at equal rates with soil containing organic C > 10,000 mg kg-1. The ratio of first-order rate constant for contaminant degradation to hydrogen peroxide consumption was used as an empirical measure of treatment efficiency. These ratios were sensitive to both the soil and organic C content and to the concentration of iron added during treatment. The efficiency ratios were highest for treatment with no iron addition; these data suggest that iron minerals and H2O2 provide a system in which Fenton-like oxidations pentachlorophenol was evaluated in goethite-, hematite-, and magnetite-silica sand at pH 3. Pentachlorophenol was degraded in the mineral-silica sand systems

  10. Spectroscopic studies of europium-tetracyclines complexes and their applications in detection of hydrogen peroxide and urea peroxide; Estudos espectroscopicos dos complexos europio-tetraciclinas e suas aplicacoes na detecao de peroxido de hidrogenio e peroxido de ureia

    Grasso, Andrea Nastri

    2010-07-01

    In this work were studied the spectroscopic properties of trivalent europium ion complexed with components of tetracycline family, chlorotetracycline, oxytetracycline and metacycline, in the presence of hydrogen peroxide and urea peroxide. Optical parameters were obtained such as absorption, emission, lifetime and calibration curves were constructed for luminescence spectra. Experiments were carried out with both inorganic compounds and europium-tetracyclines complexes in order to verify possible interferences. Studies for glucose determination were also described using europium-tetracyclines complexes as biosensors. Results show that europium tetracyclines complexes emit a narrow band in the visible region and, in the presence of hydrogen peroxide or urea peroxide there is a greater enhancement in their luminescence and lifetime. Thus, europium-tetracyclines complexes studied can be used as biosensors for hydrogen and urea peroxides determination as a low cost and room temperature method. An indirect method for glucose determination was studied by adding glucose oxidase enzyme in europium-tetracyclines complex in the presence of glucose promoting as product hydrogen peroxide. (author)

  11. Determination of hydrogen peroxide concentration in THOR coolant during reactor operation

    The concentrations of hydrogen peroxide formed in the coolant due to radiolysis were studied during THOR operation at 1 MW. The relation between doses and hydrogen peroxide formation in a neutron-gamma mixed field was investigated. The initial concentration was 2.3x10-5 g/ml at the beginning of reactor operation, and then it increased rather rapidly at the first 9 hs. The increasing rate slowed down till the end of 30 hs of operation. The maximum concentration of hydrogen peroxide was found to be 4.7x10-5 g/ml, and its decrease followed the exponential curve. (author)

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

    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.

  13. Optimization of Hydrogen Peroxide Detection for a Methyl Mercaptan Biosensor

    Shi-Gang Sun

    2013-04-01

    Full Text Available Several kinds of modified carbon screen printed electrodes (CSPEs for amperometric detection of hydrogen peroxide (H2O2 are presented in order to propose a methyl mercaptan (MM biosensor. Unmodified, carbon nanotubes (CNTs, cobalt phthalocyanine (CoPC, Prussian blue (PB, and Os-wired HRP modified CSPE sensors were fabricated and tested to detect H2O2, applying a potential of +0.6 V, +0.6 V, +0.4 V, −0.2 V and −0.1 V (versus Ag/AgCl, respectively. The limits of detection of these electrodes for H2O2 were 3.1 μM, 1.3 μM, 71 nM, 1.3 μM, 13.7 nM, respectively. The results demonstrated that the Os-wired HRP modified CSPEs gives the lowest limit of detection (LOD for H2O2 at a working potential as low as −0.1 V. Os-wired HRP is the optimum choice for establishment of a MM biosensor and gives a detection limit of 0.5 μM.

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

    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.

  15. Electrochemical reduction of hydrogen peroxide on stainless steel

    S Patra; N Munichandraiah

    2009-09-01

    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 studied by varying the concentration of H2O2 in the range from 0.2 mM to 20 mM and the sweep rate in the range from 2 to 100 mV s-1. Voltammograms at concentrations of H2O2 higher than 2 mM or at high sweep rates consist of an additional current peak, which may be due to the reduction of adsorbed species formed during the reduction of H2O2. Amperometric determination of H2O2 at -0.50 V vs SCE provides the detection limit of 5 M H2O2. A plot of current density versus concentration has two segments suggesting a change in the mechanism of H2O2 reduction at concentrations of H2O2 ≥ 2 mM. From the rotating disc electrode study, diffusion co-efficient of H2O2 and rate constant for reduction of H2O2 are evaluated.

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

    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.

  17. Hydrogen peroxide regulates cell adhesion through the redox sensor RPSA.

    Vilas-Boas, Filipe; Bagulho, Ana; Tenente, Rita; Teixeira, Vitor H; Martins, Gabriel; da Costa, Gonçalo; Jerónimo, Ana; Cordeiro, Carlos; Machuqueiro, Miguel; Real, Carla

    2016-01-01

    To become metastatic, a tumor cell must acquire new adhesion properties that allow migration into the surrounding connective tissue, transmigration across endothelial cells to reach the blood stream and, at the site of metastasis, adhesion to endothelial cells and transmigration to colonize a new tissue. Hydrogen peroxide (H2O2) is a redox signaling molecule produced in tumor cell microenvironment with high relevance for tumor development. However, the molecular mechanisms regulated by H2O2 in tumor cells are still poorly known. The identification of H2O2-target proteins in tumor cells and the understanding of their role in tumor cell adhesion are essential for the development of novel redox-based therapies for cancer. In this paper, we identified Ribosomal Protein SA (RPSA) as a target of H2O2 and showed that RPSA in the oxidized state accumulates in clusters that contain specific adhesion molecules. Furthermore, we showed that RPSA oxidation improves cell adhesion efficiency to laminin in vitro and promotes cell extravasation in vivo. Our results unravel a new mechanism for H2O2-dependent modulation of cell adhesion properties and identify RPSA as the H2O2 sensor in this process. This work indicates that high levels of RPSA expression might confer a selective advantage to tumor cells in an oxidative environment. PMID:26603095

  18. Preliminary flight test of hydrogen peroxide retro-propulsion module

    An, Sungyong; Jo, Sungkwon; Wee, Jeonghyun; Yoon, Hosung; Kwon, Sejin

    2010-09-01

    In this paper, we present the development of a retro-thruster, the design of a retro-propulsion module, and a preliminary flight of the module in a landing demonstration. First, a retro-monopropellant thruster with the maximum thrust of 350 N that employs hydrogen peroxide as a monopropellant was developed. It's thrust force, efficiency of characteristic velocity, and specific impulse were evaluated during the course of it's development. To control the thrust force, two solenoid valves and a pulse width modulation (PWM) flow control valve were incorporated into the thruster design. Second, a retro-propulsion module with a wet mass of 23 kg was designed and fabricated. All the required components including tanks, propellant tubes, a pressure regulator, valves, a retro-thruster, and support structure were integrated into the module. Finally, a preliminary flight test with thrust and altitude control was carried out successfully. In this test, the throttling of the thrust force and altitude control was performed manually for safety purposes.

  19. Diesel autothermal reforming with hydrogen peroxide for low-oxygen environments

    Highlights: • The concept of diesel reforming using hydrogen peroxide was newly proposed. • Characteristics of hydrogen peroxide was experimentally investigated. • Thermodynamically possible operating conditions were analyzed. • Catalytic performance of Ni–Ru/CGO for various diesel compounds was evaluated. • Long-term testing was successfully conducted using Korean commercial diesel. - Abstract: To operate fuel cells effectively in low-oxygen environments, such as in submarines and unmanned underwater vehicles, a hydrogen source with high hydrogen storage density is required. In this paper, diesel autothermal reforming (ATR) with hydrogen peroxide as an alternative oxidant is proposed as a hydrogen production method. Diesel fuel has higher hydrogen density than metal hydrides or other hydrocarbons. In addition, hydrogen peroxide can decompose into steam and oxygen, which are required for diesel ATR. Moreover, both diesel fuel and hydrogen peroxide are liquid states, enabling easy storage for submarine applications. Hydrogen peroxide exhibited the same characteristics as steam and oxygen when used as an oxidant in diesel reforming when pre-decomposition method was used. The thermodynamically calculated operating conditions were a steam-to-carbon ratio (SCR) of 3.0, an oxygen-to-carbon ratio (OCR) of 0.5, and temperatures below 700 °C to account for safety issues associated with hydrogen peroxide use and exothermic reactions. Catalytic activity and stability tests over Ni–Ru (19.5–0.5 wt.%)/Ce0.9Gd0.1O2−x were conducted using various diesel compounds. Furthermore, long-term diesel ATR tests were conducted for 200 h using Korean commercial diesel. The degradation rate was 3.67%/100 h without the production of ethylene

  20. Addition versus radiolytic production effects of hydrogen peroxide on aqueous corrosion of UO2

    The effects of hydrogen peroxide, H2O2, on UO2 corrosion is investigated in aerated deionized water in two types of situations. The H2O2 species is either added to water or produced by radiolysis at UO2/H2O interfaces. The concentrations vary in the range 10-5-10-1 mol l-1. The radiolysis is induced by irradiating the UO2/H2O interfaces with a He2+-beam emerging from the UO2 discs into the solutions. Both the evolution of the aqueous solutions and the UO2 surfaces are characterised. In both types of experiments, the alteration of UO2 results in the formation of the same secondary phase, an hydrated uranium peroxide called studtite (UO2(O)2 . 4H2O). However, the uranium release at the interface differs strikingly. It is much higher when H2O2 is produced by irradiation than when it is simply added. Furthermore, it varies in opposite direction as a function of the H2O2 concentration. This gives evidence that the chemistry at the UO2 interface under irradiation differs significantly from the chemistry induced by simply adding H2O2 to the solution. Rutherford backscattering spectrometry is used to determine the growth rate of the corrosion layer. For H2O2 addition, the layer thickness increases with increasing leaching time, although as time increases, the U release tends towards zero. It is possible to establish the first empirical equation relating the corrosion rates to the added H2O2 concentrations. For H2O2 radiolytic production, the growth is continuous as irradiation time increases but the growth rate seems to decrease as the layer grows and to reach a limit

  1. Oxidative aromatization of Hantzsch 1,4-dihydropyridines by aqueous hydrogen peroxide-acetic acid

    2007-01-01

    A simple method for the oxidative aromatization of Hantzsch 1,4-dihydropyridines to the corresponding pyridines is achieved by using hydrogen peroxide as green oxidant and acetic acid as catalyst in aqueous solution.

  2. [The Clinical Application Status and Development Trends of Hydrogen Peroxide Low Temperature Plasma Sterilizers].

    Zhuang, Min; Zheng, Yunxin; Chen, Ying; Hou, Bin; Xu, Zitian

    2016-01-01

    The hydrogen peroxide low temperature plasma sterilization technology solved the problems of thermo-sensitive materials' disinfection and sterilization based on its development and unique characteristics. This paper introduced the researches of clinical application quality control, and showed the hydrogen peroxide low temperature plasma sterilizers were being widely used in hospitals and highly recognized. According to the clinical data and the literatures of the domestic equipment in preliminary application, it could be concluded that the technology maturity of domestic hydrogen peroxide low temperature plasma sterilizers was in a high level. The advantages of using domestic hydrogen peroxide low temperature plasma sterilizers to do disinfection and sterilization included lower cost, safer, faster and non-toxic, etc. Also the management system should be improved and the clinical staff should master the technical essentials, obey the procedures strictly, verify periodically and offer full monitoring to upgrade the quality of sterilization. PMID:27197500

  3. Macrophage Response to UHMWPE Submitted to Accelerated Ageing in Hydrogen Peroxide

    Rocha, Magda F.G.; Mansur, Alexandra A.P.; Martins, Camila P.S.; Edel F Barbosa-Stancioli; Mansur, Herman S

    2010-01-01

    Ultra-high molecular weight polyethylene (UHMWPE) has been the most commonly used bearing material in total joint arthroplasty. Wear and oxidation fatigue resistance of UHMWPE are regarded as two important properties to extend the longevity of knee prostheses. The present study investigated the accelerated ageing of UHMWPE in hydrogen peroxide highly oxidative chemical environment. The sliced samples of UHMWPE were oxidized in a hydrogen peroxide solution for 120 days with their total level o...

  4. Measurements of the partitioning of hydrogen peroxide in a stratiform cloud

    Noone, Kevin J.; OGREN, JOHN A.; NOONE, K. BIRGITTA; HALLBERG, ANNELI; Fuzzi, Sandro; Lind, John A.

    2011-01-01

    Simultaneous measurements of hydrogen peroxide in cloud droplets and in the air in which the droplets were suspended are presented. In addition, a description of the new technique used to make the measurements is also presented. The ratio of the measured cloudwater concentration to the equilibrium cloudwater concentration predicted using Henry's law and the measured gas-phase hydrogen peroxide was 0.64 (S.D = 0.32, n= 74). Analysis of both random and potential systematic errors indicate that ...

  5. Carbon Sources for Yeast Growth as a Precondition of Hydrogen Peroxide Induced Hormetic Phenotype

    Ruslana Vasylkovska; Natalia Petriv; Halyna Semchyshyn

    2015-01-01

    Hormesis is a phenomenon of particular interest in biology, medicine, pharmacology, and toxicology. In this study, we investigated the relationship between H2O2-induced hormetic response in S. cerevisiae and carbon sources in yeast growth medium. In general, our data indicate that (i) hydrogen peroxide induces hormesis in a concentration-dependent manner; (ii) the effect of hydrogen peroxide on yeast reproductive ability depends on the type of carbon substrate in growth medium; and (iii) meta...

  6. INVOLVEMENT OF CATALASE IN SACCHAROMYCES CEREVISIAE HORMETIC RESPONSE TO HYDROGEN PEROXIDE

    Ruslana Vasylkovska

    2015-05-01

    Full Text Available In this study, we investigated the relationship between catalase activity and H2O2-induced hormetic response in budding yeast S. cerevisiae. In general, our data suggest that: (i hydrogen peroxide induces hormesis in a concentration- and time-dependent manner; and (ii the effect of hydrogen peroxide on yeast colony growth positively correlates with the activity of catalase that suggests the enzyme involvement in overall H2O2-induced stress response and hormetic response in yeast.

  7. INVOLVEMENT OF CATALASE IN SACCHAROMYCES CEREVISIAE HORMETIC RESPONSE TO HYDROGEN PEROXIDE

    Ruslana Vasylkovska; Nadia Burdylyuk; Halyna Semchyshyn

    2015-01-01

    In this study, we investigated the relationship between catalase activity and H2O2-induced hormetic response in budding yeast S. cerevisiae. In general, our data suggest that: (i) hydrogen peroxide induces hormesis in a concentration- and time-dependent manner; and (ii) the effect of hydrogen peroxide on yeast colony growth positively correlates with the activity of catalase that suggests the enzyme involvement in overall H2O2-induced stress response and hormetic response in yeast.

  8. Oxidation of PAHs in water solutions by ultraviolet radiation combined with hydrogen peroxide

    Dorota Olejnik; Jacek S. Miller; Stanisław Ledakowicz

    1999-01-01

    The destruction of three polycyclic aromatic hydrocarbons (PAHs): benzo[a]pyrene, chrysene and fluorene in aqueous solution using advanced oxidation process H2O2/UV was investigated. The influence of pH, initial hydrogen peroxide and radical scavenger concentrations on the reaction rate was studied. The oxidation reactions most rapidly run in neutral and acidic solution at optimal hydrogen peroxide concentration (ca. 0.01 M). The degradation of benzo[a]pyrene and chrysene follows radical reac...

  9. The contribution of rainwater to variability in surface ocean hydrogen peroxide

    Cooper, William J.; SALTZMAN, ERIC S.; Zika, Rod G

    1987-01-01

    Hydrogen peroxide concentrations have been determined in marine rain from the Gulf of Mexico, the western Atlantic Ocean, and one rain event off the Florida Keys. In several cases, simultaneous measurements of the concentration of H2O2 in the surface ocean were also determined. These measurements were made with the ship under way using a continuous flow sampling system with the intake at the bow. In shallow stratified layers, rain events can increase the existing hydrogen peroxide concentrati...

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

    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, often biological, treatment steps. A drinking water company in the western part of the Netherlands investigated decomposition of about 5.75 mg L−1 hydrogen peroxide in pre-treated Meuse river water ...

  11. Penetration of 38% hydrogen peroxide into the pulp chamber in bovine and human teeth submitted to office bleach technique.

    Camargo, Samira Esteves Afonso; Valera, Marcia Carneiro; Camargo, Carlos Henrique Ribeiro; Gasparoto Mancini, Maria Nadir; Menezes, Marcia Maciel

    2007-09-01

    This study evaluated the pulp chamber penetration of peroxide bleaching agent in human and bovine teeth after office bleach technique. All the teeth were sectioned 3 mm apical of the cement-enamel junction and were divided into 2 groups, A (70 third human molars) and B (70 bovine lateral incisors), that were subdivided into A1 and B1 restored by using composite resin, A2 and B2 by using glass ionomer cement, and A3 and B3 by using resin-modified glass ionomer cement; A4, A5, B4, and B5 were not restored. Acetate buffer was placed in the pulp chamber, and the bleaching agent was applied for 40 minutes as follows: A1-A4 and B1-B4, 38% hydrogen peroxide exposure and A5 and B5, immersion into distilled water. The buffer solution was transferred to a glass tube in which leuco crystal violet and horseradish peroxidase were added, producing a blue solution. The optical density of the blue solution was determined by spectrophotometer and converted into microgram equivalents of hydrogen peroxide. Data were submitted to analysis of variance and Dunnett, Kruskal-Wallis, and Tukey tests (5%). A higher level of hydrogen peroxide penetrated into the pulp chamber in resin-modified glass ionomer cements in bovine (0.79 +/- 0.61 microg) and human (2.27 +/- 0.41 microg) groups. The bleaching agent penetration into the pulp chamber was higher in human teeth for any experimental situation. The penetration of the hydrogen peroxide depends on restorative materials, and under the conditions of this study human teeth are more susceptible to penetration of bleaching agent into the pulp chamber than bovine teeth. PMID:17931936

  12. Strategies for designing supported gold-palladium bimetallic catalysts for the direct synthesis of hydrogen peroxide.

    Edwards, Jennifer K; Freakley, Simon J; Carley, Albert F; Kiely, Christopher J; Hutchings, Graham J

    2014-03-18

    Hydrogen peroxide is a widely used chemical but is not very efficient to make in smaller than industrial scale. It is an important commodity chemical used for bleaching, disinfection, and chemical manufacture. At present, manufacturers use an indirect process in which anthraquinones are sequentially hydrogenated and oxidized in a manner that hydrogen and oxygen are never mixed. However, this process is only economic at a very large scale producing a concentrated product. For many years, the identification of a direct process has been a research goal because it could operate at the point of need, producing hydrogen peroxide at the required concentration for its applications. Research on this topic has been ongoing for about 100 years. Until the last 10 years, catalyst design was solely directed at using supported palladium nanoparticles. These catalysts require the use of bromide and acid to arrest peroxide decomposition, since palladium is a very active catalyst for hydrogen peroxide hydrogenation. Recently, chemists have shown that supported gold nanoparticles are active when gold is alloyed with palladium because this leads to a significant synergistic enhancement in activity and importantly selectivity. Crucially, bimetallic gold-based catalysts do not require the addition of bromide and acids, but with carbon dioxide as a diluent its solubility in the reaction media acts as an in situ acid promoter, which represents a greener approach for peroxide synthesis. The gold catalysts can operate under intrinsically safe conditions using dilute hydrogen and oxygen, yet these catalysts are so active that they can generate peroxide at commercially significant rates. The major problem associated with the direct synthesis of hydrogen peroxide concerns the selectivity of hydrogen usage, since in the indirect process this factor has been finely tuned over decades of operation. In this Account, we discuss how the gold-palladium bimetallic catalysts have active sites for the

  13. Production of uranium peroxide

    The process of recovering uranium values as uranium peroxide from an aqueous uranyl solution containing dissolved vanadium and sodium impurities, characterized by treating the uranyl solution with hydrogen peroxide in an amount sufficient to have an excess of at least 0.5 parts H2O2 per part vanadium (V2O5) above the stoichio-metric amount required to form the uranium peroxide, the hydrogen peroxide treatment being carried out in three sequential phases consisting of: 1) a precipitation phase in which the hydrogen peroxide is added to the uranyl solution to precipitate the uranium peroxide and the pH of the reaction media maintained in the range of 3.0 to 7.0 for a period of 5 to 180 60 minutes after the hydrogen peroxide addition; 2) a digestion phase in which the pH of the reaction medium is maintained in the range of 3.0 to 7.0 for a period of 5 to 180 minutes and 3) a final phase in which the pH of the reaction media is maintained in the range of 4.0 to 7.0 for a period of 1 to 60 minutes during which time the uranium peroxide is separated from the reaction solution containing the dissolved vanadium and sodium impurities, the excess hydrogen peroxide aforesaid being maintained until the uranium peroxide is separated from the reaction mixture

  14. Modular advanced oxidation process enabled by cathodic hydrogen peroxide production.

    Barazesh, James M; Hennebel, Tom; Jasper, Justin T; Sedlak, David L

    2015-06-16

    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

  15. Hydrogen peroxide induces apoptosis via a mitochondrial pathway in chondrocytes

    Zhuang, Cai-ping; Liang, Qian; Wang, Xiao-ping; Chen, Tong-sheng

    2012-03-01

    The degenerative joint disease such as osteoarthritis (OA) is closely associated with the death of chondrocytes in apoptosis fashion. Hydrogen peroxide (H2O2), higher expression following acute damage in OA patients, has been shown to be up-regulated during apoptosis in a bulk of experimental models. This study was aimed to explore the mechanism of H2O2-induced rabbit chondrocytes apoptosis. Articular cartilage was biopsied from the joints of 6 weeks old New Zealand rabbits. Cell Counting Kit (CCK-8) assay was used to assess the inhibitory effect of H2O2 on cell viability. H2O2 treatment induced a remarkable reduction of cell viability. We used flow cytometry to assess the form of cell death with Annexin-V/PI double staining, and found that H2O2 treatment induced apoptosis in a dose-and time-dependent manner. Exposure of chondrocytes to 1.5 mM of H2O2 for 2 h induced a burst apoptosis that can be alleviated by N-acetyl cysteine (NAC) pretreatment, an anti-oxidant amino-acid derivative. Loss of mitochondria membrane potential (▵Ψm) was evaluated using confocal microscopy imaging and flow cytometry (FCM). H2O2 treatment induced a marked reduction of ▵Ψm, and the abrupt disappearance of ▵Ψm occurred within 5 minutes. These results indicate that H2O2 induces a rapid apoptosis via a mitochondrial pathway in rabbit chondrocytes.

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

    Tebekeme Okoko; Diepreye Ere

    2012-01-01

    Objective: 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. Methods: 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. Results: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 (P<0.05). The extract also reduced hydrogen peroxide induced erythrocyte haemolysis and lipid peroxidation significantly when compared with ascorbic acid (P<0.05). The IC50 values were 7.33 mg/mL and 1.58 mg/mL for inhibition of haemolysis and lipid peroxidation, respectively. In all cases, ascorbic acid (the reference antioxidant) possessed higher activity than the extract. Conclusions:The findings show that C. papaya 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.

  17. Energy Efficient Catalytic Activation of Hydrogen peroxide for Green Chemical Processes: Final Report

    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

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

    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

  19. Chronic lead exposure decreases the vascular reactivity of rat aortas: the role of hydrogen peroxide.

    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.

  20. Preparation of uranium oxide powder for nuclear fuel pellet fabrication with uranium peroxide recovered from uranium oxide scraps by using a carbonate-hydrogen peroxide solution

    This work studied a way to reclaim uranium from contaminated UO2 oxide scraps as a sinterable UO2 powder for UO2 fuel pellet fabrication, which included a dissolution of the uranium oxide scraps in a carbonate solution with hydrogen peroxide and a UO4 precipitation step. Dissolution characteristics of reduced and oxidized uranium oxides were evaluated in a carbonate solution with hydrogen peroxide, and the UO4 precipitation were confirmed by acidification of uranyl peroxo-carbonate complex solution. An agglomerated UO4 powder obtained by the dissolution and precipitation of uranium in the carbonate solution could not be pulverized into fine UO2 powder by the OREOX process, because of submicron-sized individual UO4 particles forming the agglomerated UO4 precipitate. The UO2 powder prepared from the UO4 precipitate could meet the UO2 powder specifications for UO2 fuel pellet fabrication by a series of steps such as dehydration of UO4 precipitate, reduction, and milling. The sinterability of the reclaimed UO2 powder for fuel pellet fabrication was improved by adding virgin UO2 powder in the reclaimed UO2 powder. A process to reclaim the contaminated uranium scraps as UO2 fuel powder using a carbonate solution was finally suggested. (author)

  1. Converting Chemical Energy to Electricity through a Three-Jaw Mini-Generator Driven by the Decomposition of Hydrogen Peroxide.

    Xiao, Meng; Wang, Lei; Ji, Fanqin; Shi, Feng

    2016-05-11

    Energy conversion from a mechanical form to electricity is one of the most important research advancements to come from the horizontal locomotion of small objects. Until now, the Marangoni effect has been the only propulsion method to produce the horizontal locomotion to induce an electromotive force, which is limited to a short duration because of the specific property of surfactants. To solve this issue, in this article we utilized the decomposition of hydrogen peroxide to provide the propulsion for a sustainable energy conversion from a mechanical form to electricity. We fabricated a mini-generator consisting of three parts: a superhydrophobic rotator with three jaws, three motors to produce a jet of oxygen bubbles to propel the rotation of the rotator, and three magnets integrated into the upper surface of the rotator to produce the magnet flux. Once the mini-generator was placed on the solution surface, the motor catalyzed the decomposition of hydrogen peroxide. This generated a large amount of oxygen bubbles that caused the generator and integrated magnets to rotate at the air/water interface. Thus, the magnets passed under the coil area and induced a change in the magnet flux, thus generating electromotive forces. We also investigated experimental factors, that is, the concentration of hydrogen peroxide and the turns of the solenoid coil, and found that the mini-generator gave the highest output in a hydrogen peroxide solution with a concentration of 10 wt % and under a coil with 9000 turns. Through combining the stable superhydrophobicity and catalyst, we realized electricity generation for a long duration, which could last for 26 000 s after adding H2O2 only once. We believe this work provides a simple process for the development of horizontal motion and provides a new path for energy reutilization. PMID:27093949

  2. Mushroom extract protects against hydrogen peroxide-induced toxicity in hepatic and neuronal human cultured cells.

    Guizani, Nejib; Waly, Mostafa I

    2012-11-15

    Hydrogen peroxide is an oxidative stress agent that is associated with depletion of intracellular glutathione and inhibition of antioxidant enzymes in different cell lines. Consumption of antioxidant-rich foods reduces cellular oxidative stress and its related health problems. This study aimed to assess the antioxidant properties of mushroom, Agaricus bisporous cultivar extract, against hydrogen peroxide induced oxidative stress in cultured human hepatic (HepG2) and neuronal (SH-SY5Y) cells. In this study, hydrogen peroxide caused significant oxidative stress in HepG2 and SH-SY5Y cells as demonstrated by glutathione depletion, impairment of total antioxidant capacity and inhibition of antioxidant enzymes (glutathione peroxidase, catalase and superoxide dismutase). Agaricusbisporous extract ameliorated the observed hydrogen peroxide-induced oxidative cellular insult as indicated by restoring the activity of glutathione and the assayed antioxidant enzymes to control levels. The results suggest that mushroom extract as antioxidant properties and protects against the oxidative stress induced by hydrogen peroxide-in cultured human hepatic and neuronal cells. PMID:24261122

  3. Kinetics and mechanism of the furan peroxide formation in the reaction of furfural with hydrogen peroxide in the presence and absence of sodium molybdate

    Kinetics of the initial stage of the reaction of furfural with hydrogen peroxide are studied in the presence of Na2MoO4 in water and without catalytic additions in n-butanol. Organic peroxide having in its disposal Mo(6), which is the only product on the initial stage of the reaction, is formed since the first minutes of oxidation of furfural by hydrogen peroxide with the presence of Na2MoO4. The mechanisms of conversion of furfural in the Na2MoO4 - H2O system and its oxidation by peroxide without sodium molybdate are discussed. Schemes of formation of furfural complexes based on the results of kinetic studies are suggested. Comparison of obtained data demonstrates that presence of the sodium molybdates in the reaction medium trends to change of reaction procedure in the hydrogen peroxide

  4. Functional, structural, and chemical changes in myosin associated with hydrogen peroxide treatment of skeletal muscle fibers

    Prochniewicz, Ewa; Lowe, Dawn A.; Spakowicz, Daniel J; Higgins, LeeAnn; O'Conor, Kate; Thompson, LaDora V.; Deborah A Ferrington; Thomas, David D.

    2007-01-01

    To understand the molecular mechanism of oxidation-induced inhibition of muscle contractility, we have studied the effects of hydrogen peroxide on permeabilized rabbit psoas muscle fibers, focusing on changes in myosin purified from these fibers. Oxidation by 5 mM peroxide decreased fiber contractility (isometric force and shortening velocity) without significant changes in the enzymatic activity of myofibrils and isolated myosin. The inhibitory effects were reversed by treating fibers with d...

  5. Mitochondria are the source of hydrogen peroxide for dynamic brain-cell signaling

    Bao, Li; Avshalumov, Marat V.; Patel, Jyoti C.; Lee, Christian R.; Miller, Evan W.; Chang, Christopher J.; Rice, Margaret E.

    2009-01-01

    Hydrogen peroxide (H2O2) is emerging as a ubiquitous small-molecule messenger in biology, particularly in the brain, but underlying mechanisms of peroxide signaling remain an open frontier for study. For example, dynamic dopamine transmission in dorsolateral striatum is regulated on a subsecond timescale by glutamate via H2O2 signaling, which activates ATP-sensitive potassium (KATP) channels to inhibit dopamine release. However, the origin of this modulatory H2O2 has been elusive. Here we add...

  6. Reaction kinetics of hydrogen peroxide in teeth for teeth whitening applications

    Fang, Grace C.

    2013-01-01

    Clinical parameters for dental whitening such as peroxide concentration and treatment time have been empirically derived. However, limited quantitative analyses examine reactivity of hydrogen peroxide on in vivo tooth stains under various catalytic settings. The wide range of possible activators and stains are challenging in creating a standardized tooth model to isolate various effects for clinical applications. This study uses three model systems to determine the effects of heat, light, met...

  7. Re-Examining the Role of Hydrogen Peroxide in Bacteriostatic and Bactericidal Activities of Honey

    Brudzynski, Katrina; Abubaker, Kamal; St-Martin, Laurent; Castle, Alan

    2011-01-01

    The aim of this study was to critically analyze the effects of hydrogen peroxide on growth and survival of bacterial cells in order to prove or disprove its purported role as a main component responsible for the antibacterial activity of honey. Using the sensitive peroxide/peroxidase assay, broth microdilution assay and DNA degradation assays, the quantitative relationships between the content of H2O2 and honey’s antibacterial activity was established. The results showed that: (A) the average...

  8. K-channels inhibited by hydrogen peroxide mediate abscisic acid signaling in Vicia guard cells

    2001-01-01

    A number of studies show that environmental stress conditions increase abscisic acid (ABA) and hydrogen peroxide (H2O2) levels in plant cells. Despite this central role of ABA in altering stomatal aperture by regulating guard cell ion transport, little is known concerning the relationship between ABA and H2O2 in signal transduction leading to stomatal movement. Epidermal strip bioassay illustrated that ABA-inhibited stomatal opening and ABA-induced stomatal closure were abolished partly by externally added catalase (CAT) or diphenylene iodonium (DPI), which are a H2O2 scavenger and a NADPH oxidase inhibitor respectively. In contrast, internally added CAT or DPI nearly completely or partly reversed ABA-induced closure in half-stoma. Consistent with these results, whole-cell patch-clamp analysis showed that intracellular application of CAT or DPI partly abolished ABA-inhibited inward K+ current across the plasma membrane of guard cells. H2O2 mimicked ABA to inhibit inward K+ current, an effect which was reversed by the addition of ascorbic acid (Vc) in patch clamping micropipettes. These results suggested that H2O2 mediated ABA-induced stomatal movement by targeting inward K+ channels at plasma membrane.

  9. Estimation of Lipid Peroxidation Induced by Hydrogen Peroxide in Cultured Human Lymphocytes

    Siddique, Yasir Hasan; Ara, Gulshan; Afzal, Mohammad

    2011-01-01

    Malondialdehyde (MDA) is used for the estimation of damage by reactive oxygen species. MDA is a major reactive aldehyde resulting from the peroxidation of biological membranes. The most common method used to assess MDA production is the thiobarbituric acid (TBARS) assay. However, the value of this method is curbed by low specificity and has been criticized for its use in human studies. In the present study we have used an alternative method for the estimation of MDA production i.e. reaction o...

  10. Investigation of the oxidation of hydrochloric acid in scrubbing solutions containing hydrogen peroxide

    Oxidation and absorption of nitrogen oxides by a solution containing sulphuric, nitric acids and hydrogen peroxide have been investigated. The oxidation of nitric oxide is dependent among others on hydrogen peroxide concentration total acidity and temperature. The absorption of N O2 by the scrubbing solution (H2 S O4,H N O3 and H2 O2) in all cases studied is not less than 98%. The oxidation of chloride into chlorine gas increases as the concentration of each of hydrochloric acid, nitric oxide and nitric acid increases. On the other hand as the concentration of hydrogen peroxide increases the amount of chlorine gas decreases. The results show that the oxidation of chloride into chlorine gas is mainly due to nitrogen dioxide. 7 fig., 2 tab

  11. Oxidation of uranium dioxide by hydrogen peroxide in sulfuric acid medium

    The oxidation of uranium dioxide by hydrogen peroxide in sulfuric acid medium was studied. It was found that in the UO2-H2O2-Fe/sup (II,III)/-H2SO4 system, the value of the oxidation potential (OP) is determined by the amount of Fe/sup (III)/ ions formed as the result of the oxidation of ferrous oxide by hydrogen peroxide. At normal temperature, H2O2 displays its oxidizing activity with respect to uranium dioxide at OP values of 500-550 mV, and at elevated temperature (40-600C) and in the presence of iron ions, at 400-450 mV. In a wide range of pH values, hydrogen peroxide as oxidizing agent considerably surpasses oxidizing agents such as nitrous acid, manganese dioxide, manganates, and permanganates. The process proceeds vigorously not only with the participation of iron ions, but also in their absence

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

    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.

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

    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 10-7 to 10-3 mol/l and sensitivity of 10-8 mol/l. This method was also applied to the determination of total catechin levels in green tea, black tea and roasted green tea

  14. Wind-eroded silicate as a source of hydrogen peroxide on Mars

    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...... 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......-erosion effectively eroded the sand over weeks of tumbling and we saw a clear correlation between an increase in surface area and the release of hydrogen peroxide. The production of hydrogen peroxide depended on the presence of atmospheric oxygen and was inhibited by atmospheric carbon dioxide. Nevertheless, taking...

  15. Atmospheric Pressure Humid Argon DBD Plasma for the Application of Sterilization - Measurement and Simulation of Hydrogen, Oxygen, and Hydrogen Peroxide Formation

    Kirkpatrick, Mike; Dodet, Bénédicte; Odic, Emmanuel

    2007-01-01

    Hydrogen, oxygen, and hydrogen peroxide have been measured downstream of an atmospheric pressure humid argon dielectric barrier discharge. The yield of the three species was studied as a function of the discharge power and gas flow rate. Hydrogen peroxide was measured after dissolution into water downstream of the discharge, while hydrogen and oxygen were measured in the gas phase. The production rates of both hydrogen and oxygen were found to be at least one order of magnitude greater than t...

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

    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 (pColor changes were significant for different tested bleaching therapies (pcolor change observed for 35% hydrogen peroxide gel. No difference in opacity was detected for all analyzed parameters. Fluorescence changes were influenced by composite resin brand (pbrand 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. PMID:22433032

  17. ECF BLEACHING WITH A FINAL HYDROGEN PEROXIDE STAGE: IMPACT ON THE CHEMICAL COMPOSITION OF Eucalyptus globulus KRAFT PULPS

    Pedro E. G. Loureiro

    2010-11-01

    Full Text Available Two industrial elemental chlorine free (ECF bleaching sequences, D0(EOPD1(EPD2 and OQ(PODP, are compared with respect to the bulk content of lignin, carboxyl, hexeneuronic acids (HexA, and reducing groups after each bleaching stage. HexA groups contribute significantly to the total content of carboxyl groups, and their degradation during chlorine dioxide bleaching is reflected by a decrease of the carboxyl content. The higher degradation using an enhanced use of oxygen-based bleaching chemicals is associated with a higher fiber charge reduction, mainly due to xylan depletion. Additionally, the effect of process variables of a laboratory final hydrogen peroxide stage on the chemical composition of the fully bleached pulp (D0(EOPD1P and OQ(PODP is studied. The ability of final peroxide bleaching to raise the content of carboxyl groups is dependent on the operating conditions and pulp bleaching history. A balance between carbohydrate oxidation and dissolution of oxidized groups determines the effect on fiber charge. The effect of hydrogen peroxide stabilizers added into the final stage on the content of carboxyl groups is also reported.

  18. The Erosion Properties of Chlorine Dioxide and Hydrogen Peroxide on Bovine Teeth

    Ablal MA; Jarad FD; Adeyemi AA

    2015-01-01

    Objectives: The aim of this study was to assess the erosion potential of chlorine dioxide and hydrogen peroxide on bovine teeth. Methods: Sixty bovine crowns were ground and polished to give flat surfaces. The crowns were subjected to heavy staining cycles then equally divided into 3 treatment groups; chlorine dioxide (ClO2), hydrogen peroxide (H2O2), and deionised water (H2O). Specimens in each group were immersed in 150 ml of the treatment for seven 2 min cycle in addition...

  19. Effectiveness and kinetics of hydrogen peroxide and nitrate-enhanced biodegradation of hydrocarbons

    Techniques are rapidly developing for insitu biodegradation processes of contaminations in lower water bearing formations. It is well known that underground biodegradation is limited by the lack of electron acceptors and nutrients. Hydrogen peroxide and nitrate are the most commonly applied electron acceptors to enhance in situ bioremediation of contaminated soils. This paper has two purposes. The first is to compare the effects and rates of degradation processes with hydrogen peroxide and nitrates as electron acceptors despite of differences in type of metabolism. The second is to develop a bioreactor system that allows consideration of the effects of mass transportation and evaluation of the overall kinetics for biodegradation processes in soils

  20. Neutral water-chemical regime with hydrogen peroxide dosage at the AMB-200 unit

    Results of investigations related to estimation of erosion-corrosion process rates on feed water treatment with hydrogen peroxide at the Beloyarskaya NPP second unit are given. As follows from analysis, values of electric conductivity and iron oxide concentrations reduced two times as compared with correctionless regimes. Metal erosion rate in some feed water loop sections reduced 200-600 times. Hydrogen peroxide metering for feed water provides good condition and reliable operation of feed water loop equipment, reactor circuit and process tubes of the AMB-200 reactor unit

  1. Kinetic study of hexavalent plutonium reduction by hydrogen peroxide in acid solution

    The kinetics of the reduction of hexavalent plutonium by hydrogen peroxide has been studied in perchloric, sulphuric and nitric acids. The rate of reduction is proportional to the initial concentrations of plutonium and of hydrogen peroxide and is inversely proportional to the acidity. The values of the proportionality constant k have been determined. They are very dependent on the temperature, on the ionic force and on the nature of the anion of the acid medium. An interpretation is put forward, based on the experimental results, attributing an important role to the hydrolysed species PuO2(OH)+ in the reduction kinetics. (author)

  2. Carbon Sources for Yeast Growth as a Precondition of Hydrogen Peroxide Induced Hormetic Phenotype

    Ruslana Vasylkovska

    2015-01-01

    Full Text Available Hormesis is a phenomenon of particular interest in biology, medicine, pharmacology, and toxicology. In this study, we investigated the relationship between H2O2-induced hormetic response in S. cerevisiae and carbon sources in yeast growth medium. In general, our data indicate that (i hydrogen peroxide induces hormesis in a concentration-dependent manner; (ii the effect of hydrogen peroxide on yeast reproductive ability depends on the type of carbon substrate in growth medium; and (iii metabolic and growth rates as well as catalase activity play an important role in H2O2-induced hormetic response in yeast.

  3. Carbon Sources for Yeast Growth as a Precondition of Hydrogen Peroxide Induced Hormetic Phenotype.

    Vasylkovska, Ruslana; Petriv, Natalia; Semchyshyn, Halyna

    2015-01-01

    Hormesis is a phenomenon of particular interest in biology, medicine, pharmacology, and toxicology. In this study, we investigated the relationship between H2O2-induced hormetic response in S. cerevisiae and carbon sources in yeast growth medium. In general, our data indicate that (i) hydrogen peroxide induces hormesis in a concentration-dependent manner; (ii) the effect of hydrogen peroxide on yeast reproductive ability depends on the type of carbon substrate in growth medium; and (iii) metabolic and growth rates as well as catalase activity play an important role in H2O2-induced hormetic response in yeast. PMID:26843865

  4. Hydrogen peroxide yields in the radiolysis of aerated aqueous solutions of formic acid

    Radiation-chemical yields of hydrogen peroxide during radiolysis of formic acid deaerated aqueous solutions were measured under the action of gamma and accelerated electron radiation in the range of high doses up to (10-15 kGy) and average dose rate of 10 Gy/s. It was ascertained that growth of radiation dose involves at first increase in concentration of hydrogen peroxide formed, passing through a maximum, and then decrease to actually zero values at doses exceeding 1.5 kGy. The character of the dependence is explained by gradual consumption of oxygen with the dose increase

  5. What are the sources of hydrogen peroxide production by heart mitochondria?

    Grivennikova, Vera G.; Kareyeva, Alexandra V.; Vinogradov, Andrei D.

    2010-01-01

    Coupled rat heart mitochondria produce externally hydrogen peroxide at the rates which correspond to about 0.8 and 0.3 per cent of the total oxygen consumption at State 4 with succinate and glutamate plus malate as the respiratory substrates, respectively. Stimulation of the respiratory activities by ADP (State 4–State 3 transition) decreases the succinate- and glutamate plus malate-supported H2O2 production 8- and 1.3-times, respectively. NH4+ strongly stimulates hydrogen peroxide formation ...

  6. Process Development and Design of Chlorine Dioxide Production Based on Hydrogen Peroxide

    陈赟; 江燕斌; 钱宇

    2004-01-01

    This paper presents a process development and design of chlorine dioxide production based on hydrogen peroxide. The process is characterized by cleaner production, high efficiency, and waste minimization. Optimization of process conditions, selection of equipment, and experiment of recycle of waste acid are carried out. The process design is realized in consideration of several aspects such as operation, material, equipment design and safety. An industrialized process flowsheet is developed according to experiment. A pilot testing is carried out to confirm the lab results. Process design of chlorine dioxide production based on hydrogen peroxide is realized.

  7. Plutonium(IV) peroxide formation in nitric medium and kinetics Pu(VI) reduction by hydrogen peroxide

    Reduction of plutonium (VI) to Pu(IV) with hydrogen peroxide is a step in industrial processes used to purify plutonium nitrate solutions. This operation must be carefully controlled, in order to avoid any formation of the Pu(IV) peroxide green precipitate and to obtain exclusively Pu(IV). This led us to study the acidity and Pu and H2O2 concentrations influences on the precipitate appearance and to perform a Pu(VI) reduction kinetic study on a wide range of acidities ([HNO3]: 0.5 to 8 M), plutonium concentrations ([Pu(VI)]: 0.1 to 0.8 M) and [H2O2]/[Pu(VI)] ratio (from 1 to 8). Thus, the domain of Pu(IV) peroxide formation and the reactional paths were established. With the exception of 0.5 M nitric acid medium, the kinetic curves show two distinct regims: the first one corresponds to an induction period where the Pu(VI) concentration doesn't change, the second corresponds to a linear decrease of Pu(VI). An increase of the temperature greatly accelerates the Pu(VI) reduction rate while [H2O2]/[Pu(VI)] has almost no influence. The Pu(VI) total reduction time decreases when initial concentration of plutonium increases. By increasing nitric acid concentration from 0.5 M to 6 M, the total Pu(VI) reduction time decreases. This time increases when [HNO3] varies from 6 M to 8 M. (orig.)

  8. Chemiluminescence behavior of sodium hydrogen carbonate in the potassium permanganate-hydrogen peroxide reaction

    2010-01-01

    Chemiluminescence (CL) phenomenon of hydrogen peroxide with potassium permanganate in the presence of sodium hydrogen carbonate was reported.Effects of the surfactant on the CL system were investigated.Nonionic surfactants could effectively increase the CL signal.Radical scavengers and organic reagents such as nitro blue tetrazolium chloride (NBT),cytochrome c,sodium azide,ascorbic acid,thiourea,tert-butanol and dimethyl sulphoxide were used to study the emitting species.CL emission spectrum was recorded and the results showed that the maximal emission wavelengths of NaHCO3-H2O2-KMnO4 system were 440 and 634 nm.The mechanism was discussed based on electron spin resonance (ESR) spectra,fluorescence spectra and UV-vis absorption spectra.The addition of rhodamine B or uranine into this CL system enhanced the CL signal.It was due to part of the energy transfer from singlet oxygen and excited triplet dimers of two CO2 molecules to rhodamine B or uranine.The CL could be induced by excited rhodamine B or uranine.

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

    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. PMID:26365231

  10. [The effect of cadmium chloride and hydrogen peroxide on the lipid peroxidation and fractional composition of lipids in hepatocytes of rats].

    Borikov, O Iu; Kaliman, P A

    2004-01-01

    The isolated hepatocytes were incubated in the medium, containing cadmium chloride or hydrogen peroxide. Influence of the latter on the intensity of lipid peroxidation and contents of some lipids fractions, as well as viability of hepatocytes in these conditions has been studied. It is shown that under such cultivation conditions the activation of lipid peroxidation in the hepatocytes takes place. Its activation in presence of cadmium chloride was one of the factors of the membranes damage. The changes in the content of some fractions of lipids were similar both under the incubations of the cells with cadmium chloride and hydrogen peroxide. This allows one to suppose that cadmium chloride causes changes in the lipid composition of membranes as a result of intensification of lipid peroxidation. PMID:15915720

  11. Investigating the hydrogen peroxide quenching capacity of proteins in polyphenol-rich foods.

    Zhou, Lisa; Elias, Ryan J

    2011-08-24

    Polyphenols are widely regarded as antioxidants, due in large part to their free radical scavenging activities and their ability to disrupt radical chain propagation. However, recent studies have demonstrated that the oxidation of some polyphenolic compounds, such as the tea-derived compound (-)-epigallocatechin-3-gallate (EGCG), results in the generation of reactive oxygen species that can potentially compromise the oxidative stability of food lipids under some conditions. In this present study, the rate of hydrogen peroxide (H(2)O(2)) generation and its stability, resulting from EGCG oxidation in Tween 80- and sodium caseinate-stabilized oil-in-water (O/W) emulsions in the presence of iron (25 μM Fe(3+) from FeCl(3)), were examined. Observed H(2)O(2) levels in protein-stabilized emulsions were significantly lower across all treatments as compared to surfactant-stabilized emulsions. The lower observed H(2)O(2) concentrations seen in the protein system are likely due to the antioxidant effects of the added proteins, which either prevented the generation of or more likely scavenged the peroxide. All protein-stabilized emulsions containing EGCG showed increases in carbonyl concentrations, a marker of protein oxidation, throughout the study. The H(2)O(2) scavenging activity of aqueous phase and interfacial caseinate and whey protein isolate (WPI) was also evaluated. Both proteins showed concentration-dependent scavenging of H(2)O(2) with caseinate displaying significantly higher scavenging abilities at all concentrations. These results suggest that food proteins may play an important role in mitigating the pro-oxidant effects of polyphenols. PMID:21751811

  12. Efficient Method for the Determination of the Activation Energy of the Iodide-Catalyzed Decomposition of Hydrogen Peroxide

    Sweeney, William; Lee, James; Abid, Nauman; DeMeo, Stephen

    2014-01-01

    An experiment is described that determines the activation energy (E[subscript a]) of the iodide-catalyzed decomposition reaction of hydrogen peroxide in a much more efficient manner than previously reported in the literature. Hydrogen peroxide, spontaneously or with a catalyst, decomposes to oxygen and water. Because the decomposition reaction is…

  13. Dissolution kinetics of U3Si2 particles in alkaline hydrogen peroxide

    Nonproliferation concerns leading to the conversion from high- to low-enriched uranium sparked interest in U3Si2 dispersion targets as an option for 99Mo production. Dissolution of irradiated targets is an important step in recovering fission-product 99Mo. Alkaline hydrogen peroxide solutions dissolved U3Si2 particles in an open batch reactor; samples were analyzed for total peroxide and uranium concentrations as functions of time and temperature. Dissolution rates are highest at 1 to 1.5 M NaOH and change little for initial base concentrations from 0.5 to 2.5 M NaOH, indicating relatively robust process conditions. Uranium dissolution rates depend most strongly on the equilibrium concentration of the peroxyl ion (O2H-), an equilibrium product of hydrogen peroxide (H2O2) and hydroxyl ion (OH-). Temperature and equilibrium concentrations of O2H- and OH- are included in a uranium dissolution rate model

  14. Electrodeposited nanostructured MnO2 for non-enzymatic hydrogen peroxide sensing

    Electrodeposited MnO2 nanostructure was synthesized on indium tin oxide coated glass electrode by cyclic voltammetry. The as obtained samples were subsequently characterized by atomic force microscopy and their electro-catalytic response towards hydrogen peroxide in alkaline medium of 0.1M NaOH was studied using cyclic voltammetry and amperometry

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

    Pierce, Brian; Wichmann, Jesper; Tran, Tam H.; Cheetamun, Roshan; Bacic, Antony; Meyer, Anne S.

    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...

  16. Decolorization of Synthetic Dyes by Hydrogen Peroxide with Heterogeneous Catalysis by Mixed Iron Oxides

    Baldrian, Petr; Merhautová, Věra; Gabriel, Jiří; Nerud, František; Stopka, Pavel; Hrubý, Martin; Beneš, Milan J.

    2006-01-01

    Roč. 66, - (2006), s. 258-264. ISSN 0926-3373 R&D Projects: GA AV ČR IBS5020306 Institutional research plan: CEZ:AV0Z50200510; CEZ:AV0Z40320502; CEZ:AV0Z40500505 Keywords : degradation * synthetic dyes * hydrogen peroxide Subject RIV: EE - Microbiology, Virology Impact factor: 3.942, year: 2006

  17. Study on a hydrogen peroxide biosensor based on horseradish peroxidase/GNPs-thionine/chitosan

    Highlights: ► Glutaraldehyde was used as the bridge linking agent to covalently bonded thionine in chitosan, which is more stable and could effectively prevalent leakage of the electronic mediator. ► The effect of GNPs adsorbed HRP was first accurately characterized by bio-layer interferometry using the ForteBio Octer system. ► The application of self-assembly technology increases the biosensor stability. - Abstract: A novel hydrogen peroxide biosensor based on horseradish peroxidase/GNPs-thionine/chitosan has been developed. Gold nanoparticles fixed with horseradish peroxidase were adsorbed on glassy carbon electrode by the chitosan which cross-linked with the electron mediator of horseradish peroxidase as the bridge linking agent. The assembly procedures were monitored by UV–visible spectral scanning, bio-layer interferometry, cyclic voltammetric and alternating current impedance. The chronoamperometry was used to measure hydrogen peroxide. The hydrogen peroxide biosensor linear range of detection is 1 × 10−7–1 × 10−4 mol/L, detection limit up to 5.0 × 10−8 mol/L. Moreover the stability, reproducibility and selectivity of the biosensor were also studied and the results confirmed that the biosensor exhibit fast response to hydrogen peroxide and possess high sensitivity, good reproducibility and long-term stability.

  18. Explodability and detonability of mixtures of hydrogen peroxide and organic matter

    Heemskerk, A.H.; Scholtes, J.H.G.

    1995-01-01

    The explosive properties of mixtures of hydrogen peroxide and isopropanol were determined The mixtures appear to detonate in a well-defined range of concentrations and show extremely fast reactions in an adjacent range of concentrations if initiated by shock wave stimuli. The upper boundary of organ

  19. HYDROGEN PEROXIDE FORMATION FROM THE PHOTOOXIDATION OF FORMALDEHYDE AND ITS PRESENCE IN RAINWATER

    The photooxidation of formaldehyde with sunlamps (E(max) = 3100 A) produces hydrogen peroxide (H2O2) at varying concentrations depending upon the amount of water vapor present. It is postulated that the variable production of H2O2 is a result of condensation on the reactor surfac...

  20. Electrochemical synthesis of hydrogen peroxide: Rotating disk electrode and fuel cell studies

    The electrochemical reduction of oxygen on various catalysts was studied using the thin-layer rotating disk electrode (RDE) method. High-surface-area carbon was modified with an anthraquinone derivative and gold nanoparticles. Polytetrafluoroethylene (PTFE) and cationic polyelectrolyte (FAA) were used as binders in the preparation of thin-film electrodes. Our primary goal was to find a good electrocatalyst for the two-electron reduction of oxygen to hydrogen peroxide. All electrochemical measurements were carried out in 0.1 M KOH. Cyclic voltammetry was used in order to characterise the surface processes of the modified electrodes in O2-free electrolyte. The RDE results revealed that the carbon-supported gold nanoparticles are active catalysts for the four-electron reduction of oxygen in alkaline solution. Anthraquinone-modified high-area carbon catalyses the two-electron reduction at low overpotentials, which is advantageous for hydrogen peroxide production. In addition, the polymer electrolyte fuel cell technology was used for the generation of hydrogen peroxide. The cell was equipped with a bipolar membrane which consisted of commercial Nafion 117 as a cation-exchange layer and FT-FAA as an anion-exchange layer. The bipolar membranes were prepared by a hot pressing method. Use of the FAA ionomer as a binder for the anthraquinone-modified carbon catalyst resulted in production of hydrogen peroxide

  1. HYDROGEN PEROXIDE TREATMENT DURING EGG INCUBATION IMPROVES CHANNEL CATFISH HATCHING SUCCESS

    Three trials were conducted to evaluate the effect of hydrogen peroxide (H2O2) treatment on channel catfish Ictalurus punctatus hatching success when administered during egg incubation as a 15 min. bath or as a flow-through treatment. In the first trial, initial treatment with 100 ppm povidone iodi...

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

    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.

  3. OXIDATION OF ALCOHOLS OVER FE3+/MONTMORILLONITE-K10 USING HYDROGEN PEROXIDE

    Oxidation of various primary and secondary alcohols is studied in liquid phase at atmospheric pressure over Fe3+/montmorillonite-K10 catalyst prepared by ion-exchange method at a pH of 4 in an environmentally friendly protocol using hydrogen peroxide. The catalyst and the method ...

  4. DNA polymerase III requirement for repair of DNA damage caused by methyl methanesulfonate and hydrogen peroxide

    The pcbA1 mutation allows DNA replication dependent on DNA polymerase I at the restrictive temperature in polC(Ts) strains. Cells which carry pcbA1, a functional DNA polymerase I, and a temperature-sensitive DNA polymerase III gene were used to study the role of DNA polymerase III in DNA repair. At the restrictive temperature for DNA polymerase III, these strains were more sensitive to the alkylating agent methyl methanesulfonate (MMS) and hydrogen peroxide than normal cells. The same strains showed no increase in sensitivity to bleomycin, UV light, or psoralen at the restrictive temperature. The sensitivity of these strains to MMS and hydrogen peroxide was not due to the pcbAl allele, and normal sensitivity was restored by the introduction of a chromosomal or cloned DNA polymerase III gene, verifying that the sensitivity was due to loss of DNA polymerase III alpha-subunit activity. A functional DNA polymerase III is required for the reformation of high-molecular-weight DNA after treatment of cells with MMS or hydrogen peroxide, as demonstrated by alkaline sucrose sedimentation results. Thus, it appears that a functional DNA polymerase III is required for the optimal repair of DNA damage by MMS or hydrogen peroxide

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

    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 challen...

  6. Study of the dosage of hydrogen peroxide using ultraviolet spectrophotometry (1963)

    A continuous determination of hydrogen peroxide by mean of UV spectrophotometry at about 2000 A, gives very satisfactory results. This method seems to be well adapted to the special case of the cooling water of a nuclear reactor (10-20 mg/l H2O2) and could thus provide a new possibility of controlling this reactor. (author)

  7. Kinetics of pyrite oxidation by hydrogen peroxide in phosphoric acid solutions

    VALENTINA DIMITRIJEVIC

    1999-12-01

    Full Text Available The kinetics of pyrite oxidation by hydrogen peroxide in phosphoric acid solutions were investigated. The effects of stirring, temperature, and particle size, as well as of the hydrogen peroxide and phosphoric acid concentrations were studied. The effect of phosphate ion addition was also examined. The oxidation kinetics was found to follow a shrinking core model, with the surface chemical reaciton as the rate-controlling step. This is in accord with an activation energy of 57 kJ mol-1 and a linear relationship between the rate constant and the reciprocal of the particle radius. The reaction order with respect to the hydrogen peroxide concentration was found to be equal to unity. Variation of the phosphoric acid concentration had practically no effect on the rate of pyrite oxidation. Addition of the phosphate ion in the relatively low concentration range (0.005-0.1 mol dm-3 had a highly negative influence on the rate of pyrite oxidation, indicating that this ion has an inhibiting effect on the oxidation of pyrite by hydrogen peroxide.

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

    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. PMID:27132221

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

    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...

  10. A dissolution study of cobalt oxide by hydrogen peroxide in boric acid solution

    A dissolution study of CoO (cobaltous oxide) by hydrogen peroxide was carried out in boric acid solution at 60degC. The chemical species of dissolved cobalt are Co+2 and Co(OH)+, being equilibrated with Co(OH)2, and the concentration ratio of the both ion species is determined by pH of the solution. Hydrogen peroxide accelerates the dissolution of CoO, which occures during it is decomposed. In the case where the solution is oxygenated, Co(OH)2 in the solution and/or covering the CoO crystal surface as a layer becomes Co2O3 remarkably less soluble than CoO and the reaction rate becomes somewhat slow with decreasing pH. On the basis of the results, it could be concluded that, in order to decrease the radiation dose rate on the personnel and the Co58 inventory in primary coolant system at the minimum in the practical use, the Co58 removal procedures must be consisted of: 1) The first step in that addition of small amount of hydrogen peroxide and oxygen removal are consevtively performed several times for accelerating the dissolution of Co58 2) The second step in that only addition of relatively larger amount of hydrogen peroxide is performed for repressing the dissolution of Co58. (Author)

  11. Degradation of polycyclic aromatic hydrocarbons by hydrogen peroxide catalyzed by heterogeneous polymeric metal chelates

    Baldrian, Petr; Cajthaml, Tomáš; Merhautová, Věra; Gabriel, Jiří; Nerud, František; Stopka, P.; Hrubý, Martin; Beneš, Milan J.

    2005-01-01

    Roč. 59, - (2005), s. 267-274. ISSN 0926-3373 R&D Projects: GA AV ČR IBS5020306; GA ČR GA203/01/0944 Institutional research plan: CEZ:AV0Z7090911 Keywords : degradation * polycyclic aromatic hydrocarbon * hydrogen peroxide Subject RIV: EE - Microbiology, Virology Impact factor: 3.809, year: 2005

  12. Effect of ultrasonic pre-treatment of thermomechanical pulp on hydrogen peroxide bleaching

    Ultrasound pre-treatments of softwood TMP had been carried to evaluate its impact on the efficiency of hydrogen peroxide bleaching. The trials were performed after a factorial design of experiment using frequency, power and time as variables. The experiments were conducted in an ultrasonic bath and then bleached with hydrogen peroxide. Measurements such as brightness, L*A*B* color system coordinate, residual hydrogen peroxide and metal content were evaluated on bleached pulp. The results indicate that the effect of ultrasonic treatment on brightness was dependent on the ultrasound frequency used; the brightness increased slightly at 68 kHz and decreased at 40 and 170 kHz. These results were correlated to the ultrasound effect on the generation of transition metals (copper, iron and manganese) which are responsible for catalytic decomposition of hydrogen peroxide. The influence of metal interference was minimized by using a chelating agent such as diethylene triamine pentaacetic acid (DTPA). With the results obtained in this study we have identified a set of option conditions, e.g. 1000 W, 40 kHz, 1.5 % consistency and 0.2% addition of DTPA prior to the bleaching stage (after ultrasonic pre-treatment) who improve brightness by 2.5 %ISO.

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

    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.

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

    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)

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

    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…

  16. Combined exposure to hydrogen peroxide and light - selective effects on cyanobacteria, green algae, and diatoms

    Drábková, Michaela; Admiraal, W.; Maršálek, Blahoslav

    2007-01-01

    Roč. 41, č. 1 (2007), s. 309-314. ISSN 0013-936X Grant ostatní: -(XE) EVK2-CT-2002-57004 Institutional research plan: CEZ:AV0Z60050516 Keywords : Hydrogen peroxide * cyanobacterie * green algae * diatoms Subject RIV: EF - Botanics Impact factor: 4.363, year: 2007

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

    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.

  18. Synergetic degradation of konjac glucomannan by γ-ray irradiation and hydrogen peroxide.

    Pan, Tingtiao; Peng, Shuhui; Xu, Zhenlin; Xiong, Bo; Wen, Chenrong; Yao, Minna; Pang, Jie

    2013-04-01

    Konjac glucomannan (KGM) samples were irradiated with (60)Co γ-rays with a radiation dose of 50kGy in the presence and absence of hydrogen peroxide. The average molecular weight (Mw) and polydispersity index (PDI) of untreated and degraded samples were measured by gel permeation chromatography (GPC), revealing that γ-rays and hydrogen peroxide had a synergetic effect on degradation. Structures of untreated and degraded products were characterized with ultraviolet-visible (UV) and Fourier-transform infrared (FT-IR) spectroscopies, and X-ray diffraction (XRD). Results showed that there was no significant change in the main chain of KGM following degradation, although the crystallinity of KGM decreased. A synergetic effect of γ-rays and hydrogen peroxide was also found in the structural characterization of KGM. The physical properties of KGM changed markedly following degradation, which may increase its application potential. The mechanism of degradation of KGM in the presence and absence of hydrogen peroxide was also investigated. PMID:23499121

  19. A selective hydrogen peroxide sensor based on chemiresistive polyaniline nanowires modified with silver catalytic nanoparticles

    This paper presents a novel method to selectively detect hydrogen peroxide using a chemiresistive polyaniline nanowire network. The polyaniline nanowires modified with silver catalytic nanoparticles were demonstrated to give selective responses to hydrogen peroxide by changing the conductivity of the polyaniline. The proposed mechanism for the selectivity in the H2O2 sensing is based on a catalytic reaction between the silver nanoparticles and the hydrogen peroxide which generates hydroxide ions and water to influence the conductivity of polyaniline. The catalytic effect of the silver nanoparticles was confirmed by characterizing the relationship between the amount of catalysts and the current response. The results indicate that the rate of the catalytic reaction is proportional to the number of silver nanoparticles attached on the surfaces of polyaniline. By observing the conductance change, the developed chemiresistive sensor was able to selectively detect H2O2 while exhibiting minimal response to other chemical species. The objective of this paper is to address the selectivity issue of a chemiresistor by suggesting a catalyst-based selective detection of an analyte for a polyaniline-based chemiresistive sensor. This technology may have potential applications in microscale or microfluidic chemical and biological sensors requiring a selective detection of hydrogen peroxide concentrations. (paper)

  20. 21 CFR 172.167 - Silver nitrate and hydrogen peroxide solution.

    2010-04-01

    ... agent in bottled water. (b) Hydrogen peroxide meets the specifications of the “Food Chemicals Codex... Register approves this incorporation by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. You... treated bottled water is determined using the method for silver designated in 21 CFR...

  1. Activity of iridium-ruthenium and iridium-rhodium adsorption catalysts in decomposition of hydrogen peroxide

    Experimental data for the activities of iridium-ruthenium and iridium-rhodium adsorption catalysts in the decomposition of hydrogen peroxide are considered and the results of magnetic susceptibility measurements are presented. It is concluded that surface structures (complexes) may be formed and that micro-electronic feaures play a role in heterogeneous catalysis

  2. Role of hydrogen peroxide in competition and cooperation between Streptococcus gordonii and Actinomyces naeslundii.

    Jakubovics, Nicholas S; Gill, Steven R; Vickerman, M Margaret; Kolenbrander, Paul E

    2008-12-01

    In dental plaque alpha-haemolytic streptococci, including Streptococcus gordonii, are considered beneficial for oral health. These organisms produce hydrogen peroxide (H(2)O(2)) at concentrations sufficient to kill many oral bacteria. Streptococci do not produce catalase yet tolerate H(2)O(2). We recently demonstrated that coaggregation with Actinomyces naeslundii stabilizes arginine biosynthesis in S. gordonii. Protein arginine residues are sensitive to oxidation by H(2)O(2). Here, the ability of A. naeslundii to protect S. gordonii against self-produced H(2)O(2) was investigated. Coaggregation with A. naeslundii enabled S. gordonii to grow in the absence of arginine, and promoted survival of S. gordonii following growth with or without added arginine. Arginine-replete S. gordonii monocultures contained 20-30 microM H(2)O(2) throughout exponential growth. Actinomyces naeslundii did not produce H(2)O(2) but synthesized catalase, removed H(2)O(2) from coaggregate cultures and decreased protein oxidation in S. gordonii. On solid medium, S. gordonii inhibited growth of A. naeslundii; exogenous catalase overcame this inhibition. In coaggregate cultures, A. naeslundii cell numbers were >90% lower than in monocultures after 24 h. These results indicate that coaggregation with A. naeslundii protects S. gordonii from oxidative damage. However, high cell densities of S. gordonii inhibit A. naeslundii. Therefore, H(2)O(2) may drive these organisms towards an ecologically balanced community in natural dental plaque. PMID:18785881

  3. Phospholipase A2 activation by hydrogen peroxide during in vitro capacitation of buffalo spermatozoa.

    Shit, Sanjoy; Atreja, S K

    2004-05-01

    Progressively motile, washed buffalo spermatozoa (50 x 10(6) cells in 0.5 ml) were in vitro capacitated in HEPES containing Bovine Gamete Medium 3 (BGM3) in presence of heparin (10 microg/ml), and different concentrations of hydrogen peroxide (10 to 100 microM). Spermatozoa (60%) were capacitated in presence of heparin compared to 56% in presence of 25 microM H2O2 (optimally found suitable for capacitation). The extent of capacitation was measured in terms of acrosome reaction (AR) induced by lysophosphatidyl choline (100 microg/ml). The acrosome reacted cells were counted after triple staining. Catalase (100 microg/ml) significantly reduced the sperm capacitation to 16-18% when added with H2O2, or alone in the capacitation medium. Phospholipase A2 activity of spermatozoa increased linearly up to 50 microM H2O2 concentration included in the assay system. Moreover, significant increase in phospholipase A2 activity was observed after capacitation by both, the heparin and 25 microM H2O2. The activity was always higher in acrosome reacted cells. PMID:15233473

  4. Kansas City plant ultraviolet/ozone/hydrogen peroxide groundwater treatment system overview

    The Kansas City Plant (KCP) has committed to the utilization of a groundwater treatment system, for removal of volatile organic compounds (VOCs), that discharges a minimal amount of pollutants to the environment. An advanced oxidation process (AOP) system utilizing ozone, ultraviolet radiation, and hydrogen peroxide serves in this capacity. Packed tower aeration and activated carbon filtration are listed as best available technologies (BATs) by the Environmental Protection Agency (EPA) for the removal of VOCs in water. The disadvantage to these BATs is that they transfer the VOCs from the water medium to the air or carbon media respectively. Operation of the system began in May 1988 at a flow rate of 22.7 liters per minute (lpm) (6 gallons per minute (gpm)). An additional 102.2 lpm (27 gpm) of flow were added in October 1990. Various efforts to optimize and track the treatment unites efficiency have been carried out. A maximum influent reading of 26,590 parts per billion (ppb) of total VOCs has been recorded. Following the addition of flows, removal efficiency has averaged approximately 95%. Both air and water effluents are factored into this calculation. (author)

  5. 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

    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...

  6. Prostaglandins attenuate cardiac contractile dysfunction produced by free radical generation but not by hydrogen peroxide.

    Zimmer, K M; Karmazyn, M

    1997-11-01

    The aim of this study was to examine and compare the potential influence of cyclooxygenase or lipoxygenase derived metabolites of arachidonic acid on myocardial injury produced either by a free radical generating system consisting of purine plus xanthine oxidase or that produced by hydrogen peroxide. A free radical generating system consisting of purine (2.3 mM) and xanthine oxidase (10 U/L) as well as hydrogen peroxide (75 microM) produced significant functional changes in the absence of either significant deficits in high energy phosphates or ultrastructural damage. Prostaglandin F2 alpha (30 nM) significantly attenuated both the negative inotropic effect of purine plus xanthine oxidase as well as the ability of the free radical generator to elevate diastolic pressure. An identical concentration of prostaglandin 12 (prostacyclin) significantly reduced diastolic pressure elevation only and had no effect on contractile depression. The salutary effects of the two PGs occurred in the absence of any inhibitory influence on superoxide anion generation produced by the purine and xanthine oxidase reaction. None of prostaglandins modulated the response to hydrogen peroxide. In addition, neither prostaglandin E2 nor leukotrienes exerted any effect on changes produced by either type of oxidative stress. A 5 fold elevation in the concentrations of free radical generators or hydrogen peroxide produced extensive injury as characterized by a virtual total loss in contractility, 400% elevation in diastolic pressure, ultrastructural damage and significant depletions in high energy phosphate content. None of these effects were modulated by eicosanoid treatment. Our results therefore demonstrate a selective ability of both prostaglandin F2 alpha and to a lesser extent prostacyclin, to attenuate dysfunction produced by purine plus xanthine oxidase but not hydrogen peroxide. It is possible that these eicosanoids may represent endogenous protective factors under conditions of enhanced

  7. Temperature response and durability characterization of an optical fiber sensor for the detection of hydrogen peroxide

    Hydrogen peroxide is a precursor to damage mechanisms in numerous applications; its monitoring is important and challenging. The effect of temperature on the performance and durability of a recently developed optical fiber sensors sensitive to the presence of hydrogen peroxide in low concentrations is investigated. The sensors are fabricated by immobilizing Prussian blue within a multilayer of electrostatically self-assembled polyelectrolytes. The sensing principle of this optical electrode relies on the change in the intensity of the reflected light when Prussian white is oxidized back to the blue state due to the presence of hydrogen peroxide. The amplitude of the intensity of the reflected light is found to vary with temperature in a quadratic fashion, but the characteristic response time which correlates with concentration remains constant. Thus the sensing device retains its abilities to determine and quantify the concentration of hydrogen peroxide in a liquid solution. Additionally, the degradation of these fiber sensors when subjected to high temperature is examined. Four optical fiber sensing devices were subjected to different testing conditions and a characterization protocol that included: measurement of the intensity of the cyanide stretch (2150 cm−1) via Raman micro spectroscopy; imaging with scanning electron microscopy; and measurement of the presence of iron ions using energy dispersive X-ray spectroscopy. The results show a gradual degradation of the sensing device as a result of progressive desorption of the polyelectrolyte multilayer structure that leads to leaching of the Prussian reagent. This degradation mechanism does not compromise the functionality of the device which is found sufficiently robust for multiple tests at high temperature. The simplicity of this sensing system combined with its relative robustness and reusability make it a good a good candidate for minimally intrusive and localized monitoring of hydrogen peroxide formation in

  8. Hydrogen peroxide and the evolution of oxygenic photosynthesis

    Mckay, C. P.; Hartman, H.

    1991-01-01

    Possible pathways for the evolution of oxygenic photosynthesis in the early reducing atmosphere of the earth are discussed. It is suggested that 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 (rather than ferrous or sulfide ions) as the electron donor. It is argued that atmospheric H2O2 played the key role in inducing oxygenic photosynthesis, because, as peroxide concentrations local environments increased, primitive organisms would not only be faced with a loss of a reductant, but would be also forced to develop a biochemical apparatus (such as catalase) that would protect them against the products of oxygenic photosynthesis. This scenario allows for the early evolution of oxygenic photosynthesis at the time when global conditions were still anaerobic.

  9. Solvent extraction of tungsten with tri-n-octylamine from hydrogen peroxide solutions

    Conditions for fast metallic tungsten dissolution in hydrogen peroxide solutions are found and regularities of its extraction by tri-n-octylamine in the form of peroxide compounds and isopolytungstates from hydrochloric, sulfuric acid nitric acid solutions are studied. W and TOA ratio in the formed organic complex is determined by studying extraction isotherms using equilibrium shift, saturation, isomolar series, IR spectrometry methods and this complex'es composition is assumed. Radiochemical circuit of extraction-chromatographic separation of tungsten and rhenium is developed and a method for fast isolation of rhenium-183, 184 radio nuclides from metallic tungsten, irradiated with charged particles is proposed

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

    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

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

    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+ counter-ion, were considered. The counter-ions have been taken into consideration in so far 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 counter-ions 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. (authors)

  12. Efficacy of hydrogen peroxide in controlling mortality associated with saprolegniasis on walleye, white sucker, and paddlefish eggs

    Gaikowski, M.P.; Rach, J.J.; Drobish, M.; Hamilton, J.; Harder, T.; Lee, L.A.; Moen, C.; Moore, A.

    2003-01-01

    The efficacy of hydrogen peroxide in controlling saprolegniasis on eggs of walleye Stizostedion vitreum, white sucker Catostomus commersoni, and paddlefish Polyodon spathula was evaluated at four private, state, and federal production hatcheries participating in an Investigational New Animal Drug efficacy study (experiment 1; walleyes) and in a laboratory-based miniature egg jar incubation system (experiment 2; walleyes, white suckers, and paddlefish). Naturally occurring fungal infestations (saprolegniasis) were observed on eggs in both experiments. Confirmatory diagnosis of infested eggs from one hatchery in experiment 1 identified the pathogen as Saprolegnia parasitica. During experiment 1, eggs were treated daily for 15 min with either 0, 500, or 750 mg/L of hydrogen peroxide, and one trial compared a 500-mg/L hydrogen peroxide treatment with a formalin treatment at 1,667 mg/L. Saprolegniasis infestation was observed in control egg jars, whereas treatment with either formalin or hydrogen peroxide virtually eliminated the infestation. Hydrogen peroxide treatments of 500 mg/L either increased egg hatch or were as effective as physical removal of infested eggs in controlling mortality. Although treatment with formalin at 1,667 mg/L significantly increased the percent eye-up of walleye eggs compared with that of those treated with hydrogen peroxide at 500 mg/L, the difference was only 1.9-2.6%. In experiment 2, noneyed eggs were treated for 15 min every other day with 0, 283, 565, or 1,130 mg/L of hydrogen peroxide until the viable eggs hatched. Saprolegniasis infestation engulfed most control eggs, whereas infestation of treated eggs was either reduced or not visible. Hydrogen peroxide significantly increased egg hatch for all three species tested in experiment 2. Although hydrogen peroxide treatments as low as 283 mg/L significantly increased walleye and white sucker hatch, treatments between 500 and 1,000 mg/L are more likely to be effective in production egg

  13. Fluorescence enhancement of CdTe MPA-capped quantum dots by glutathione for hydrogen peroxide determination.

    Rodrigues, S Sofia M; Ribeiro, David S M; Molina-Garcia, L; Ruiz Medina, A; Prior, João A V; Santos, João L M

    2014-05-01

    The manipulation of the surface chemistry of semiconductor nanocrystals has been exploited to implement distinct sensing strategies in many analytical applications. In this work, reduced glutathione (GSH) was added at reaction time, as an electron-donor ligand, to markedly increase the quantum yield and the emission efficiency of MPA-capped CdTe quantum dots. The developed approach was employed in the implementation of an automated flow methodology for hydrogen peroxide determination, as this can oxidize GSH preventing its surface passivating effect and producing a manifest fluorescence quenching. After optimization, linear working calibration curve for hydrogen peroxide concentrations between 0.0025% and 0.040% were obtained (n=6), with a correlation coefficient of 0.9975. The detection limit was approximately 0.0012%. The developed approach was employed in the determination of H₂O₂ in contact lens preservation solutions and the obtained results complied with those furnished by the reference method, with relative deviations comprised between -1.18 and 4.81%. PMID:24720978

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

    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

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

    Martin, Nancy L; Bass, Paul; Liss, Steven N

    2015-01-01

    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 concentrations of

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

    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.

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

    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.

  18. Methods and apparatus for the on-site production of hydrogen peroxide

    Buschmann, Wayne E. (Inventor); James, Patrick I. (Inventor)

    2010-01-01

    Methods, apparatus, and applications for the on-site production of hydrogen peroxide are described. An embodiment of the apparatus comprises at least one anolyte chamber coupled to at least one anode, at least one catholyte chamber, wherein the at least one catholyte chamber is coupled to at least one cathode, at least one anode membrane and at least one cathode membrane, wherein the anode membrane is adjacent to the at least one anode, wherein the cathode membrane is adjacent to the at least one cathode, at least one central chamber disposed between the at least one anolyte chamber and the at least one catholyte chamber. Hydrogen peroxide is produced by reduction of an oxygen-containing gas at the cathode.

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

    Pierce, Brian C; Wichmann, Jesper; Tran, Tam H; Cheetamun, Roshan; Bacic, Antony; Meyer, Anne S

    2016-06-25

    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 70% of the original insoluble material as high molar mass soluble polysaccharides. A design of experiment was used to quantify the effects of pH, reaction time, and hydrogen peroxide concentration on the reaction yield, average molar mass, and free monosaccharides generated. The resulting product is low in protein, fat, and minerals and contains predominantly water-soluble polysaccharides of high molar mass, including arabinan, type I arabinogalactan, homogalacturonan, xyloglucan, rhamnogalacturonan, and (glucurono)arabinoxylan. This treatment provides a straightforward approach for generation of soluble soy polysaccharides and opens a new range of opportunities for this abundant and underutilized material in future research and industrial applications. PMID:27083842

  20. Hydrogen peroxide biosensor based on electrodeposition of zinc oxide nanoflowers onto carbon nanotubes film electrode

    Hui Ping Bai; Xu Xiao Lu; Guang Ming Yang; Yun Hui Yang

    2008-01-01

    A new amperometric biosensor for hydrogen peroxide was developed based on adsorption of horseradish peroxidase at the glassy carbon electrode modified with zinc oxide nanoflowers produced by electrodeposition onto multi-walled carbon nanotubes (MWNTs) firm. The morphology of the MWNTs/nano-ZnO electrode has been investigated by scanning electron microscopy (SEM), and the electrochemical performance of the electrode has also been studied by amperometric method. The resulting electrode offered an excellent detection for hydrogen peroxide at -0.11 V with a linear response range of 9.9 × 10(-7) to 2.9 × 10(-3) mol/L with a correlation coefficient of 0.991, and response time <5 s. The biosensor displays rapid response and expanded linear response range, and excellent stability.

  1. Polarographic assay based on hydrogen peroxide scavenging in determination of antioxidant activity of strong alcohol beverages.

    Gorjanović, Stanislava Z; Novaković, Miroslav M; Vukosavljević, Predrag V; Pastor, Ferenc T; Tesević, Vele V; Suznjević, Desanka Z

    2010-07-28

    Total antioxidant (AO) activity of strong alcohol beverages such as wine and plum brandies, whiskeys, herbal and sweet fruit liqueurs have been assessed using a polarographic assay based on hydrogen peroxide scavenging (HPS). Rank of order of total AO activity, expressed as percentage of decrease of anodic oxidation current of hydrogen peroxide, was found analogous with total phenolic content estimated by Folin-Ciocalteau (FC) assay and radical scavenging capacity against the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH). Application of the assay for surveying of a quarter century long maturation of plum brandy in oak barrel was demonstrated. In addition, influence of different storage conditions on preservation of AO activity of some herbal liqueurs was surveyed. Wide area of application of this simple, fast, low cost and reliable assay in analysis and quality monitoring of various strong alcohol beverages was confirmed. PMID:20604507

  2. Effect of exogenous hydrogen peroxide on biophoton emission from radish root cells.

    Rastogi, Anshu; Pospísil, Pavel

    2010-01-01

    Biophotons spontaneously emitted from radish root cells were detected using highly sensitive photomultiplier tube. Freshly isolated radish root cells exhibited spontaneous photon emission of about 4 counts s(-1). Addition of hydrogen peroxide to the cells caused significant enhancement in biophoton emission to about 500 counts s(-1). Removal of molecular oxygen using glucose/glucose oxidase system and scavengering of reactive oxygen species by reducing agents such are sodium ascorbate and cysteine completely diminished biophoton emission. Spectral analysis of the hydrogen peroxide-induced biophoton emission indicates that biophotons are emitted mainly in green-red region of the spectra. The data provided by electron paramagnetic resonance spin-trapping technique showed that formation of singlet oxygen observed after addition of H2O2 correlates with enhancement in biophoton emission. These observations provide direct evidence that singlet oxygen is involved in biophoton emission from radish root cells. PMID:20106674

  3. Vanadium(5) peroxocomplexes in catalysis of hydrogen peroxide transformations in trifluoroacetic acid

    It is found that vanadium(5) complexes in trifluoroacetic acid catalyze effectively hydrogen peroxide decomposition with formation of considerable amounts of ozone (up to 15 %). It is also found that vanadium compounds in the course of interaction with peroxytrifluoroacetic acid catalyze not only its decomposition but also decarboxylation. It is ascertained by kinetic methods that in the system V(5)-H2O2-CF3COOH a series of vanadium(5) active complexes, responsible for oxidation of all the compounds studied and ozone evolution, are formed. It is shown that in the formation of the compounds both hydrogen peroxide and peroxytrifluoroacetic acid take part. All the regularities found are explained in the framework of the model, involving intrasphere regrouping of two peroxoligands into grouping (O32-). A mathematical model, which gives an adequate description of substrate oxidation and ozone formation, is plotted

  4. Electrochemical behavior of hydrogen peroxide sensor based on new methylene blue as mediator

    MA Jie; WU Hai; ZHU Yaqi

    2007-01-01

    A novel amperometric hydrogen peroxide sensor was proposed by co-immobilizing new methylene blue (NMB) and Horseradish peroxidase (HRP) on glassy carbon electrode through covalent binding.The electrochemical behavior of the sensor was studied extensively in 0.1 mol/L phosphate buffering solution (pH = 7.0).The experiments showed NMB could effectively transfer electrons between hydrogen peroxide and glassy carbon electrode.The electron transfer coefficient and apparent reaction rate constant were determined to be 0.861 and 1.27 s-1.The kinetic characteristics and responses of sensor on HzO2 were investigated.The Michaelis constant is 8.27 mol/L and the linear dependence of current on H2O2 is in the range of 2.5-100 μmol/L.At the same time,the effects of solution pH,buffer capacity,and temperature on the sensor were examined.

  5. Synthesis of Kappa-carrageenan oligomers via synergistic action of gamma radiation and hydrogen peroxide

    In this study, the synthesis of k-carrageenan oligometers with the simultaneous action of gamma radiation and hydrogen peroxide was carried out. Effects on molecular weight and structure of k-carrageenan were assessed using GPC, UV-VIS and FT-IR. Radiation degradation yield (G(s)) and reaction rate constants (k) based on Mn values were also determined. The results showed that k-carrageenan oligomers with Mw of less than 10 kDa can be prepared easily at low doses (2.5-5 kGy) in the presence of low concentrations of hydrogen peroxide (0.25-0.5%). The G(s)) and k values increased significantly with the presence of H2O2. Structural changes in k-carrageenan treated by the degradation agents were accompanied by appearance of UV peak at 260 nm and characteristic FT-IR band at 1728 cm-1. (Author)

  6. Effect of menadione and hydrogen peroxide on catalase activity in Saccharomyces yeast strains

    Nadejda EFREMOVA

    2013-05-01

    Full Text Available It has been studied the possibility of utilization of two important oxidant factors as regulators of catalase activity in Saccharomyces yeasts. In this paper results of the screening of some Saccharomyces yeast strains for potential producers of catalase are presented. Results of the screening for potential catalase producer have revealed that Saccharomyces cerevisiae CNMN-Y-11 strain possesses the highest catalase activity (2900 U/mg protein compared with other samples. Maximum increase of catalase activity with 50-60% compared to the reference sample was established in the case of hydrogen peroxide and menadione utilization in optimal concentrations of 15 and 10 mM. This research has been demonstrated the potential benefits of application of hydrogen peroxide and menadione as stimulatory factors of catalase activity in Saccharomyces yeasts.

  7. The Life Story of Hydrogen Peroxide III: Chirality and Physical Effects at the Dawn of Life

    Ball, Rowena; Brindley, John

    2016-03-01

    It is a remarkable observed fact that all life on Earth is homochiral, its biology using exclusively the D-enantiomer of ribose, the sugar moiety of the ribonucleic acids, and the L-enantiomers of the chiral amino acids. Motivated by concurrent work that elaborates further the role of hydrogen peroxide in providing an oscillatory drive for the RNA world (Ball & Brindley 2015a, J. R. Soc. Interface 12, 20150366, and Ball & Brindley 2015b, this journal, in press), we reappraise the structure and physical properties of this small molecule within this context. Hydrogen peroxide is the smallest, simplest molecule to exist as a pair of non-superimposable mirror images, or enantiomers, a fact which leads us to develop the hypothesis that its enantiospecific interactions with ribonucleic acids led to enantioselective outcomes. We propose a mechanism by which these chiral interactions may have led to amplification of D-ribonucleic acids and extinction of L-ribonucleic acids.

  8. Kinetics study on photochemical oxidation of polyacrylamide by ozone combined with hydrogen peroxide and ultraviolet radiation

    REN Guang-meng; SUN De-zhi; CHUNG Jong Shik

    2006-01-01

    An investigation on the process of ozone combined with hydrogen peroxide and ultraviolet radiation has been carried out in order to establish the kinetics for photochemical oxidation of polyacrylamide (PAM) in aqueous solution. Effects of operating parameters, including initial PAM concentration, dosages of ozone and hydrogen peroxide, UV radiation and pH value on the photochemical oxidation of PAM, have been studied. There was an increase in photochemical oxidation rate of PAM with increasing of dosages of O3, H2O2 and ultraviolet radiation. Upon increasing of the initial PAM concentration, the photochemical oxidation rate of PAM decreased. Slight effect of pH value on the photochemical oxidation rate of PAM was observed in the experiments. The kinetics equation for the photochemical oxidation of PAM by the system has been established.

  9. Induction of repair functions by hydrogen peroxide in Chinese hamster cells

    Hydrogen peroxide has been found to kill Chinese hamster V79 cells as an exponential function of dose. When a small dose (0.9 μg/ml for 1 h) was used as a pretreatment, before exposure to higher concentrations of the same agent, the cells became more resistant to killing than those which were not so pretreated. The presence of cycloheximide or benzamide, during this pretreatment, inhibited this observed increase in resistance. This pretreatment also resulted in decreased killing efficiency by MNNG and gamma-rays, but had no effect upon UV-light-induced killing. The results suggest that proteins (repair enzymes?) are synthesized after treatment with the small dose of hydrogen peroxide, and that these induced proteins enhance the cellular repair functions for agents causing DNA breaks. (author)

  10. STUDY OF AZOSPIRILLUM LECTINS INFLUENCE ON HYDROGEN PEROXIDE PRODUCTION IN WHEAT-ROOTS

    Alen’kina S.A.

    2009-12-01

    Full Text Available It was found that two cell-surface lectins isolated from the nitrogen-fixing soil bacterium Azospirillum brasilense Sp7 and from its mutant defective in lectin activity, A. brasilense Sp7.2.3 can stimulate rapid formation of hydrogen peroxide, associated with an increase in the activities of oxalate oxidase and peroxidase in the roots of wheat seedlings. The most advantageous and most rapidly induced pathway of hydrogen peroxide formation was the oxidation of oxalic acid by oxalate oxidase because in this case, a 10-min treatment of the roots with the lectins at 10 µg ml-1 was sufficient. The data from this study attest that the Azospirillum lectins can act as inducers of adaptation processes in the roots of wheat seedlings.

  11. Non-enzymatic hydrogen peroxide sensor based on Co3O4 nanocubes

    Guang Sheng Cao; Lei Wang; Pengfei Yuan; Chao Gao; Xiaojuan Liu; Tong Li; Tianmin Li

    2014-10-01

    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 nanocubes were applied to study the electrocatalytic reduction of hydrogen peroxide (H2O2) in 0.01 M pH 7.0 phosphate buffer medium. The Co3O4 nanocubes exhibit remarkable electrocatalytic activity for H2O2 reduction. Furthermore, the obtained Co3O4 nanocubes have been employed as electrode materials for electrochemical sensing H2O2.

  12. Bioconversion of paper mill sludge to bioethanol in the presence of accelerants or hydrogen peroxide pretreatment.

    Gurram, Raghu Nandan; Al-Shannag, Mohammad; Lecher, Nicholas Joshua; Duncan, Shona M; Singsaas, Eric Lawrence; Alkasrawi, Malek

    2015-09-01

    In this study we investigated the technical feasibility of convert paper mill sludge into fuel ethanol. This involved the removal of mineral fillers by using either chemical pretreatment or mechanical fractionation to determine their effects on cellulose hydrolysis and fermentation to ethanol. In addition, we studied the effect of cationic polyelectrolyte (as accelerant) addition and hydrogen peroxide pretreatment on enzymatic hydrolysis and fermentation. We present results showing that removing the fillers content (ash and calcium carbonate) from the paper mill sludge increases the enzymatic hydrolysis performance dramatically with higher cellulose conversion at faster rates. The addition of accelerant and hydrogen peroxide pretreatment further improved the hydrolysis yields by 16% and 25% (g glucose / g cellulose), respectively with the de-ashed sludge. The fermentation process of produced sugars achieved up to 95% of the maximum theoretical ethanol yield and higher ethanol productivities within 9h of fermentation. PMID:26086086

  13. Spinach Root-Tissue Based Amperometric Biosensor for the Determination of Hydrogen Peroxide

    Lee, B.G. [Chosun University, Kwangju (Korea); Yoon, K.J. [Chongju University, Chongju (Korea); Kwon, H.S. [Chungbuk National University, Chongju (Korea)

    2000-06-01

    The response characteristics of the bioelectrode developed by the co-immobilization of spinach root tissue and ferrocene in a carbon paste matrix for the amperometric determination of hydrogen peroxide were evaluated. In the range of electrode potential examined (-0.3{approx}0.0 V vs. Ag/AgCl), the response time was relatively short (t{sub 95%}=11.8 sec) and it responded in the wide range of pH. Also, its detection limit was 2.25*10{sup -6}M (S/N=3) and a relative standard deviation of the measurements which were repeated 15 times using 1.0*10{sup -3}M hydrogen peroxide was 1.87%. The bioelectrode sensitivity decreased to 40% of the original value in 19 days of continuous use. (author). 35 refs., 8 figs.

  14. Study of the hydrogen peroxide bleaching agent effects on bovine enamel using X-ray fluorescence

    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)

  15. Effects of 15% carbamide peroxide and 40% hydrogen peroxide on the microhardness and color change of composite resins.

    Sedighe Sadat Hashemi Kamangar

    2014-04-01

    Full Text Available 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.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.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.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.

  16. CIDEX, SAVLON AND HYDROGEN PEROXIDE: WHICH OF THEM IS MORE EFFECTIVE IN DISINFECTION OF VENTILATOR TUBES

    H SOLTANI NEZHAD

    2001-12-01

    Full Text Available Introduction: Nasocomial infections threat any hospitalized patient, specially in intensive care unit. Incidence of these infections has been reported from 1.9 to more than 25 percent. The most common nasocomial infection in intensive care units (ICU is pneumonia caused by endotraheal intubation and mechanical ventilation. The best procedure for pneumonia prevention in patients under mechanical ventilation is utilization of suitable and proper techniques for equipment sterilization: The goal of this study is determination and comparison of disinfectant materials (cidex, savlon and hydrogen peroxide about their effects on incidence and type of mechanical ventilators breathing tubes contamination in intensive care unit. Methods: This is an experimental trial which was done on three groups of mechanical ventilator breathing tubes. Each group contained 20 samples. These three groups of breathing tubes were disinfected with cidex, savlon and hydrogen peroxide. Samples were obtained from tubes for microbial culture berore and after disinfection. Samples were cultured on blood agar. The results of microbial culturing were compared between three groups. Results: There was no significant difference between three groups of breathing tubes about microbial types and number of colony counted before disinfection. There was no significant difference between cultured colony numbers in three groups before and after disinfection. Cidex, savlon and hydrogen peroxide could decrease incidence of contamination to 100, 98.09 and 100 percent, respectively. Discussion: All of tested chemical materials have the same results in disinfection. Hydrogen peroxide has less adverse effect on human and environment than cidex. It is less expensive than cidex. So, we recommend to use this material for disifection of mechanical ventilator berthing tubes.

  17. New considerations on hydrogen peroxide and related substances as food additives in view of carcinogenicity.

    Ito, R

    1982-01-01

    The use of hydrogen peroxide as a labile and safe food preservative in fish cake and boiled noodles has recently been restricted by the Japanese government, since hyperplasia has been found in the duodenum of mice after long-term peroral study. The action of compounds with resembling mode of action, potassium bromate as an improving agent in bread, and sodium chlorate as a weed killer are discussed in this paper in view of developmental and environmental pharmacology. PMID:7078983

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

    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...

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

    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 ( H 2 O 2 ) production in brain cells. For selective imaging of H 2 O 2 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 H 2 O 2 and mitochondria peroxy yellow 1 detects mitochondrial H 2 O 2 . Two-photon absorption cross ...

  20. Hydrogen Peroxide Contributes to the Epithelial Cell Death Induced by the Oral Mitis Group of Streptococci

    Okahashi, Nobuo; Sumitomo, Tomoko; Nakata, Masanobu; Sakurai, Atsuo; Kuwata, Hirotaka; Kawabata, Shigetada

    2014-01-01

    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 ba...

  1. The Role of Hydrogen Peroxide in Environmental Adaptation of Oral Microbial Communities

    Lin Zhu; Jens Kreth

    2012-01-01

    Oral streptococci are able to produce growth-inhibiting amounts of hydrogen peroxide (H2O2) as byproduct of aerobic metabolism. Several recent studies showed that the produced H2O2 is not a simple byproduct of metabolism but functions in several aspects of oral bacterial biofilm ecology. First, the release of DNA from cells is closely associated to the production of H2O2 in Streptococcus sanguinis and Streptococcus gordonii. Extracellular DNA is crucial for biofilm development and stabilizati...

  2. Molecular Imaging Approaches to Understanding the Roles of Hydrogen Peroxide Biology in Stress and Development

    Dickinson, Bryan Craig

    2010-01-01

    The production of hydrogen peroxide (H2O2) in biological systems is associated with a variety of pathologies including neurodegenerative diseases, cancer, and the general process of aging. However, a growing body of evidence suggests that the reactivity of this particular reactive oxygen species (ROS) is also harnessed for physiological processes. Molecular imaging using fluorescence microscopy offers a valuable approach for deciphering the multifaceted roles of H2O2 in biological processes. ...

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

    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...

  4. Role for the oxyS Gene in Regulation of Intracellular Hydrogen Peroxide in Escherichia coli

    González-Flecha, Beatriz; Demple, Bruce

    1999-01-01

    Intracellular hydrogen peroxide is regulated in Escherichia coli by OxyR in response to the metabolic production of H2O2. Here, we show that the untranslated oxyS RNA controlled by OxyR has a role in this regulation. The oxyS transcript appears to affect the metabolic output of H2O2 rather than the removal of H2O2 by catalases-hydroperoxidases.

  5. Photosensitized decomposition of hydrogen peroxide by the uranyl ion, production of hydroperoxide radicals

    The photosensitized decomposition of hydrogen peroxide by the uranyl ion in sulfuric acid media has been demonstrated and the kinetics of oxygen evolution have been measured as a function of the initial concentrations. The HO2 radical stabilized by complexation with UO22+ is an intermediate in this decomposition. This reaction can be employed in the photoassisted oxidation of diverse organic molecules using UO22+ as the sensitizer

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

    Zhou, Aifen

    2010-01-01

    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 gen...

  7. Hydrogen peroxide mobilizes Ca2+ through two distinct mechanisms in rat hepatocytes

    Sato, Hirohiko; Takeo, Teruko; Liu, Qiang; Nakano, Kyoko; Osanai, Tomohiro; Suga, Sechiko; Wakui, Makoto; Wu, Jie

    2008-01-01

    Aim: Hydrogen peroxide (H2O2) is produced during liver transplantation. Ischemia/reperfusion induces oxidation and causes intracellular Ca2+ overload, which harms liver cells. Our goal was to determine the precise mechanisms of these processes. Methods: Hepatocytes were extracted from rats. Intracellular Ca2+ concentrations ([Ca2+]i), inner mitochondrial membrane potentials and NAD(P)H levels were measured using fluorescence imaging. Phospholipase C (PLC) activity was detected using exogenous...

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

    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. (orig.)

  9. Hydrogen peroxide – production, fate and role in redox signaling of tumor cells

    Lennicke, Claudia; Rahn, Jette; Lichtenfels, Rudolf; Wessjohann, Ludger A; Seliger, Barbara

    2015-01-01

    Hydrogen peroxide (H2O2) is involved in various signal transduction pathways and cell fate decisions. The mechanism of the so called “redox signaling” includes the H2O2-mediated reversible oxidation of redox sensitive cysteine residues in enzymes and transcription factors thereby altering their activities. Depending on its intracellular concentration and localization, H2O2 exhibits either pro- or anti-apoptotic activities. In comparison to normal cells, cancer cells are characterized by an in...

  10. Polymer Supported Heterogenous Catalysts for Direct Synthesis of Hydrogen Peroxide in Absence of Selectivity Enhancers

    Sterchele, Stefano

    2013-01-01

    The research program developed during the Ph.D. School is focused on the study of metal catalysts supported on cross-linked functional polymers (CFPs) for the direct synthesis of hydrogen peroxide. In the last twenty years this compound has become a commodity with a constant increasing demand because of its strong oxidant properties and the formation of water as the reduction byproduct. In particular, H2O2 is widely employed as environmentally-friendly bleaching and cleaning agent. The...

  11. Protection of Bovine Mammary Epithelial Cells from Hydrogen Peroxide-Induced Oxidative Cell Damage by Resveratrol

    Xiaolu Jin; Kai Wang; Hongyun Liu; Fuliang Hu; Fengqi Zhao; Jianxin Liu

    2016-01-01

    The mammary epithelial cells (MECs) of high-producing dairy cows are likely to be subject to oxidative stress (OS) due to the intensive cell metabolism. The objectives of this study were to investigate the cytoprotective effects of resveratrol against hydrogen peroxide- (H2O2-) induced OS in cultured bovine MECs (MAC-T). Pretreatment of MAC-T cells with resveratrol could rescue the decrease in cell viability and resulted in lower intracellular reactive oxygen species (ROS) accumulation after ...

  12. Patterns of hydrogen peroxide among lakes of the Mackenzie Delta and potential effects on bacterial production

    Febria, Catherine Maria

    2005-01-01

    Lakes in the Mackenzie Delta have complex patterns of dissolved organic carbon (DOC) ranging from low levels of coloured DOC in lakes frequently flooded with riverwater to high levels of non-coloured DOC in infrequently flooded lakes. Hydrogen peroxide (H202) levels measured in 40 lakes at three times, ranging from summer solstice to late summer were highest around the solstice and in lakes of intermediate flood-frequency. Diurnal dynamics of H202, tracked for 40 hours during 24-hour sunlight...

  13. Oxidative stress markers in neurological diseases and disorders: electrochemical detection of hydrogen peroxide and nitric oxide

    O'Riordan, Saidhbhe

    2013-01-01

    The aim of this thesis is to further demonstrate the electrochemical detection of nitric oxide (NO) and hydrogen peroxide (H2O2) in-vitro, to advance the previously demonstrated detection of brain NO and to demonstrate the novel in-vivo detection of H2O2 using a paired catalase-based biosensor. We have recently successfully demonstrated the real-time detection of brain NO using a previously characterised Nafion®-modified platinum (Pt) electrochemical sensor. Additionally, th...

  14. Generation of hydrogen peroxide in the developing rat heart: the role of elastin metabolism

    Wilhelm, J.; Ošťádalová, Ivana; Vytášek, R.; Vajner, L.

    2011-01-01

    Roč. 358, 1-2 (2011), s. 215-220. ISSN 0300-8177 R&D Projects: GA MŠk(CZ) 1M0510 Grant ostatní: GA ČR(CZ) GAP303/11/0298 Institutional research plan: CEZ:AV0Z50110509 Keywords : rat heart * ontogenetic development * hydrogen peroxide * elastin * fluorescence Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery Impact factor: 2.057, year: 2011

  15. Photocatalytic degradation of Phenol Red using complexes of some transition metals and hydrogen peroxide

    SAVITRI LODHA

    2008-06-01

    Full Text Available The photocatalytic degradation of Phenol Red was investigated using thiocyanate complexes of iron, copper, cobalt and hydrogen peroxide. The rate of photocatalytic degradation of the dye was followed spectrophotometrically. The effect of the variation of different parameters, such as pH, concentration of the complexes and dye, amount of H2O2 and light intensity on the rate of photocatalytic degradation was also studied. A tentative mechanism for the photocatalytic degradation of Phenol Red is proposed.

  16. Experimental evaluation of hydrogen peroxide catalysts for monopropellant attitude control thrusters

    Palmer, Matthew James

    2014-01-01

    Currently the space community relies on propellants such as hydrazine and its derivatives in propulsion systems aboard satellites and spacecraft. However their highly toxic and carcinogenic nature results in significant costs in handling, storage and transport compared to less toxic propellants. It is due to this benefit that there is a renewed interest in ‘green’ or less toxic propellants. One such green propellant is hydrogen peroxide. This liquid propellant must be catalytically decomposed...

  17. Towards understanding a distinct hydrogen peroxide electrocatalytic enhancement using surfactant-based coatings on silver

    Goodison, Alan; Gonzalez-Macia, Laura; Killard, Anthony J.; Morrin, Aoife

    2013-01-01

    The detection of hydrogen peroxide has been shown to be very important in recent years due to its relevant role in many industrial applications as well as biological reactions. We are interested in it as a quantitative marker for oxidase-based biosensor applications where it is produced when substrate (e.g., glucose, cholesterol) is catalysed by its respective oxidase enzyme. Previously, a commercial silver flake-based screen-printing ink (PF-410, Acheson®), when coated with surfactant and...

  18. Novel Fe@Fe-O@Ag nanocomposite for efficient non-enzymatic sensing of hydrogen peroxide

    Here, we present a novel non-enzymatic electrochemical sensor based on a zerovalent iron–iron oxide–silver nanocomposite (Fe@Fe-O@Ag) which is suitable for highly sensitive detection of hydrogen peroxide. Silver nanoparticles were prepared by simple reduction of silver ions on the surface of nanoscale zerovalent iron (nZVI) owing to the strong reductant efficiency of nZVI. The morphology, chemical and phase composition of the Fe@Fe-O@Ag nanocomposite was monitored by TEM, SEM, X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDX). The electrochemical properties of Fe@Fe-O@Ag modified glassy carbon electrodes were characterized by voltammetric techniques and electrochemical impedance spectroscopy (EIS). The experimental data indicated that Fe@Fe-O did not contribute significantly to hydrogen peroxide sensing. Thus, Fe@Fe-O just serves as a substrate for the deposition of silver nanoparticles, whereas H2O2 detection is principally effected by the silver nanoparticles. Electrodes modified with the Fe@Fe-O@Ag nanocomposite showed a stable and sensitive response towards hydrogen peroxide reduction, exhibiting a wide linear dependence over H2O2 concentrations from 5 μmol L−1 to 1 mmol L−1 with a sensitivity of 460.34 μA μM−1 cm−2 and detection limit of 5.19 × 10−9 mol L−1. These results imply that the proposed Fe@Fe-O@Ag nanocomposite could be successfully used as a highly efficient and stable platform for hydrogen peroxide detection

  19. Improved sensing response of photo activated ZnO thin film for hydrogen peroxide detection.

    Parthasarathy, S; Nandhini, V; Jeyaprakash, B G

    2016-11-15

    The nanostructured ZnO thin films were deposited using spray pyrolysis technique. Formation of polycrystalinity with hexagonal wurtzite structure was observed from the structural study. Highly dense spherical shaped nanoparticles with fine crystallites were observed from the surface morphological studies. The light induced hydrogen peroxide vapour sensing was done using chemi-resistive method and its effect on the sensing response was studied and reported. PMID:27491004

  20. The reaction of hydrogen peroxide with nitrogen dioxide and nitric oxide.

    Gray, D.; Lissi, E.; Heicklen, J.

    1972-01-01

    The reactions were studied with the aid of a mass spectrometer. A pinhole bleed system provided continuous sampling of the gas mixture in the cell during the reaction. It was found that the homogeneous reactions of nitric oxide and nitrogen dioxide with hydrogen peroxide are too slow to be of any significance in the upper atmosphere. However, the heterogeneous reactions may be important in the conversion of nitric oxide to nitrogen dioxide in the case of polluted urban atmospheres.

  1. Green tea polyphenols protect spinal cord neurons against hydrogen peroxide-induced oxidative stress

    Zhao, Jianbo; Fang, Shiqiang; Yuan, Yajiang; Guo, Zhanpeng; Zeng, Jinhao; GUO, YUE; Tang, Peifu; Mei, Xifan

    2014-01-01

    Green tea polyphenols are strong antioxidants and can reduce free radical damage. To investigate their neuroprotective potential, we induced oxidative damage in spinal cord neurons using hydrogen peroxide, and applied different concentrations (50–200 μg/mL) of green tea polyphenol to the cell medium for 24 hours. Measurements of superoxide dismutase activity, malondialdehyde content, and expression of apoptosis-related genes and proteins revealed that green tea polyphenol effectively alleviat...

  2. Patient satisfaction with a novel one-step hydrogen peroxide solution

    Schafer J; Steffen R.; Rah MJ

    2014-01-01

    Jeffery Schafer, Robert Steffen, Marjorie J Rah Bausch & Lomb Incorporated, Rochester, NY, USA Purpose: We aimed to evaluate the product performance of a novel one-step hydrogen ­peroxide cleaning and disinfecting solution, PeroxiClear (“Test” solution), when used by habitual Clear Care users to bilaterally clean and disinfect their soft contact lenses, for approximately 2 weeks.Methods: This was a 2-week, open-label, bilateral eye study designed to include subjects...

  3. Comparison efficiency of both sonochemical and sonochemical/hydrogen peroxide processes forcyanide removal from aqueous solutions

    Reza Shokohi; Amir Hossein Mahvi; Ziaeddin Bonyadi

    2009-01-01

    (Received 5 October, 2009 ; Accepted 23 December, 2009)AbstractBackground and purpose: Cyanide is a species of high toxicity that is found mostly in industrial effluents such as electroplating, metal mining, metallurgy and metal cleaning processes. Entrance of it to existing environment contains a hazardous to health. The purpose of this study was to compare efficiency of both sonochemical and sonochemical / hydrogen peroxide processes for cyanide removal from aqueous solutions.Materials and ...

  4. Genetic and Physiological Responses of Bifidobacterium animalis subsp. lactis to Hydrogen Peroxide Stress

    Oberg, Taylor S.; Ward, Robert E.; Steele, James L.; Broadbent, Jeff R.

    2013-01-01

    Consumer interest in probiotic bifidobacteria is increasing, but industry efforts to secure high cell viability in foods is undermined by these anaerobes' sensitivity to oxidative stress. To address this limitation, we investigated genetic and physiological responses of two fully sequenced Bifidobacterium animalis subsp. lactis strains, BL-04 and DSM 10140, to hydrogen peroxide (H2O2) stress. Although the genome sequences for these strains are highly clonal, prior work showed that they differ...

  5. A neural fuzzy model applied to hydrogen peroxide bleaching of non-wood soda pulps

    Rosal, Antonio; Valls Vidal, Cristina; Ferrer, Ana; Rodríguez, Alejandro

    2012-01-01

    A neural fuzzy model was used to examine the influence of pulp bleaching variables of empty fruit bunches from oil palm (EFB) and Hesperaloe funifera, such as soda concentration (0.5-3%), hydrogen peroxide concentration (1-10%) and processing time (1-3 h), on Kappa number, brightness and viscosity. The experimental results are reproduced with errors below 10% and 15% for EFB and H. funifera, respectively. Bleaching pulp simulation permits to obtain optimal values of the operating variables, s...

  6. Effect of catechins and tannins on hydroxyl radical formation in depleted uranium-hydrogen peroxide systems

    The effects of catechins and tannins on the uranyl ion (UO2+2)-hydrogen peroxide (H2O2) system were examined using the spin-trapping method. Epigallocatechin (EGC), having low ·OH-scavenging ability, significantly enhanced and accelerated the hydroxyl radical (·OH) formation in the UO2+2-H2O2 solution. Epigallocatechin gallate (EGCG), having high ·OH-scavenging ability, fairly enhanced and accelerated hydroxyl radical (·OH) formation in the UO2+2-H2O2 solution. These results indicate that the enhancement and acceleration of ·OH formation are caused by the reduction of UO2+2 to UO2+ by EGC and EGCG. The effects of tannins on ·OH formation in the UO2+2-H2O2 solution varied with tannins. Mimosa (MMT) and quebracho (QBT) tannins enhanced and accelerated ·OH formation, while chestnut (CNT), mylobaran (MBT) and Chinese gallo- (CGT) tannins heavily depressed it. In the solution containing persimmon (PST) and gambir (GBT) tannins, the depression of ·OH formation caused by the strong coupling with UO2+2 ion should be added to the enhancement caused by the reduction of UO2+2 to UO2+. MBT indicated the highest ability to scavenge ·OH in the UV-irradiated H2O2 solution, and MMT, the lowest. In summary, MMT and QBT, classified as condensed tannins, have very high abilities to reduce UO2+2 to UO2+, similarly to catechins such as EGC and EGCG, while MBT, a hydrolysable tannin, has higher abilities to scavenge ·OH. (author)

  7. The alkaline aluminium/hydrogen peroxide power source in the Hugin II unmanned underwater vehicle

    Hasvold, Øistein; Johansen, Kjell Håvard; Mollestad, Ole; Forseth, Sissel; Størkersen, Nils

    In 1993, The Norwegian Defence Research Establishment (FFI) demonstrated AUV-Demo, an unmanned (untethered) underwater vehicle (UUV), powered by a magnesium/dissolved oxygen seawater battery (SWB). This technology showed that an underwater range of at least 1000 nautical miles at a speed of 4 knots was possible, but also that the maximum hotel load this battery system could support was very limited. Most applications for UUV technology need more power over a shorter period of time. Seabed mapping using a multibeam echo sounder mounted on an UUV was identified as a viable application and the Hugin project was started in 1995 in cooperation with Norwegian industry. For this application, an endurance of 36 h at 4 knots was required. Development of the UUV hull and electronics system resulted in the UUV Hugin I. It carries a Ni/Cd battery of 3 kW h, allowing up to 6 h under-water endurance. In parallel, we developed a battery based on a combination of alkaline Al/air and SWB technology, using a circulating alkaline electrolyte, aluminium anodes and maintaining the oxidant concentration in the electrolyte by continuously adding hydrogen peroxide (HP) to the electrolyte. This concept resulted in a safe battery, working at ambient pressure (balanced) and with sufficient power and energy density to allow the UUV Hugin II to make a number of successive dives, each of up to 36 h duration and with only 1 h deck time between dives for HP refill and electrolyte exchange. After 100 h, an exchange of anodes takes place. The power source consists of a four-cell Al/HP battery, a DC/DC converter delivering 600 W at 30 V, circulation and dosing pumps and a battery control unit. Hugin II is now in routine use by the Norwegian Underwater Intervention AS (NUI) which operates the UUV for high-precision seabed mapping down to a water depth of 600 m.

  8. Amperometric determination of hydrogen peroxide by functionalized carbon nanotubes through EDC/NHS coupling chemistry.

    Jeykumari, D R Shobha; Narayanan, S Sriman

    2007-06-01

    The electrochemistry of the redox mediator Toluidine blue (TB) which was covalently linked to the carboxyl group of the multiwalled carbon nanotubes (MWNTs) by coupling reactions, in which N-hydroxysuccinimide was used to assist 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride catalyzed amidation reaction is described. The results from cyclic voltammetry (CV) and amperometry suggested that the redox mediator is linked to the surface of the MWNTs and the nanotubes showed an obvious promotion for the direct electron-transfer between the redox mediator and the electrode. A couple of well-defined redox peak of TB was observed in a phosphate buffer solution (pH 7.0). The redox mediator immobilized to MWNTs exhibits remarkable electrocatalytic activity for the reduction of hydrogen peroxide (H2O2). The analytical applicability of the modified electrode for the determination of hydrogen peroxide was examined. A linear response in the concentration range of 6.8 x 10(-7)-3.4 x 10(-2) M (r = 0.9958) was obtained with detection limit of 3.4 x 10(-7) M for the determination of hydrogen peroxide. The modified electrode has advantages of being highly stable, sensitive, ease of construction and use. PMID:17654948

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

    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). PMID:24035719

  10. Photoproduction of hydrogen peroxide in aqueous solution from model compounds for chromophoric dissolved organic matter (CDOM)

    Highlights: • CDOM produces hydrogen peroxide in sunlit surface waters. • Quinone moieties have been proposed as the photo-active chromophore in CDOM. • Hydrogen peroxide is produced in irradiated aqueous quinone solutions. • Concentrations and production rates are comparable to humic and fulvic acids. • Optical properties post-irradiation were similar to CDOM. - Abstract: To explore whether quinone moieties are important in chromophoric dissolved organic matter (CDOM) photochemistry in natural waters, hydrogen peroxide (H2O2) production and associated optical property changes were measured in aqueous solutions irradiated with a Xenon lamp for CDOM model compounds (dihydroquinone, benzoquinone, anthraquinone, napthoquinone, ubiquinone, humic acid HA, fulvic acid FA). All compounds produced H2O2 with concentrations ranging from 15 to 500 μM. Production rates were higher for HA vs. FA (1.32 vs. 0.176 mM h−1); values ranged from 6.99 to 0.137 mM h−1 for quinones. Apparent quantum yields (Θapp; measure of photochemical production efficiency) were higher for HA vs. FA (0.113 vs. 0.016) and ranged from 0.0018 to 0.083 for quinones. Dihydroquinone, the reduced form of benzoquinone, had a higher production rate and efficiency than its oxidized form. Post-irradiation, quinone compounds had absorption spectra similar to HA and FA and 3D-excitation–emission matrix fluorescence spectra (EEMs) with fluorescent peaks in regions associated with CDOM

  11. Hydrogen peroxide production by ion irradiation of thin water ice films

    In this paper we present the results of new experiments on ion irradiation of water ice performed on thin films to study the synthesis of the hydrogen peroxide molecule and discuss the possibility of detecting it in icy mantles on interstellar grains. The used experimental technique has been in situ infrared spectroscopy. We have irradiated thin films (i.e. the ice thickness was smaller than the penetration depth of the used ion) with three different ions, namely 200 keV of H+ and He+ and 400 keV of Ar++. The experiments were carried out at temperatures of 16 and 77 K. We have found that hydrogen peroxide is produced by all of the different ions at both temperatures. The detection of such a molecule has been possible from the study of its infrared feature centered at about 2850 cm-1 (3.5 μm). The obtained results also show that the produced H2O2/H2O(%) ratio is greater for the heaviest ion (∼6% for the case of Ar++) and that H+ is the ion that produces the smallest quantity (∼1%). These upper limits in the production of hydrogen peroxide constrain the quantity of H2O2 that can be formed after bombardment by cosmic particles on icy mantles of grains in the interstellar medium. (authors)

  12. Effectiveness of ultraviolet devices and hydrogen peroxide systems for terminal room decontamination: Focus on clinical trials.

    Weber, David J; Rutala, William A; Anderson, Deverick J; Chen, Luke F; Sickbert-Bennett, Emily E; Boyce, John M

    2016-05-01

    Over the last decade, substantial scientific evidence has accumulated that indicates contamination of environmental surfaces in hospital rooms plays an important role in the transmission of key health care-associated pathogens (eg, methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, Clostridium difficile, Acinetobacter spp). For example, a patient admitted to a room previously occupied by a patient colonized or infected with one of these pathogens has a higher risk for acquiring one of these pathogens than a patient admitted to a room whose previous occupant was not colonized or infected. This risk is not surprising because multiple studies have demonstrated that surfaces in hospital rooms are poorly cleaned during terminal cleaning. To reduce surface contamination after terminal cleaning, no touch methods of room disinfection have been developed. This article will review the no touch methods, ultraviolet light devices, and hydrogen peroxide systems, with a focus on clinical trials which have used patient colonization or infection as an outcome. Multiple studies have demonstrated that ultraviolet light devices and hydrogen peroxide systems have been shown to inactivate microbes experimentally plated on carrier materials and placed in hospital rooms and to decontaminate surfaces in hospital rooms naturally contaminated with multidrug-resistant pathogens. A growing number of clinical studies have demonstrated that ultraviolet devices and hydrogen peroxide systems when used for terminal disinfection can reduce colonization or health care-associated infections in patients admitted to these hospital rooms. PMID:27131140

  13. Comparative study on the catalytic performance of metal oxide catalysts for decomposition of hydrogen peroxide

    Commercial CuO and ZnO powders were analyzed for their catalytic activity under different experimental conditions. The mentioned catalysts were characterized by scanning electron microscope, X-ray diffractometery, Fourier transform infrared spectrometry and BET surface area. The decomposition of hydrogen peroxide was studied in the presence of commercial CuO and ZnO under different experimental conditions. Effect of pH on the decomposition reaction was used to evaluate the mechanism of the decomposition reaction. Surface negative sites were responsible for the decomposition of hydrogen peroxide. Rate constants were calculated for the decomposition reactions in pH and temperature ranges of 9-13 and 30-70 degree C, respectively. The observed increase in rate constants with increase in pH and temperature was attributed to the increase in surface negativity of both the solid catalysts. The high surface charge negativity (low PZC) and high surface area of CuO were the dominant factors for the better catalytic activity of the solid as compared to ZnO. The comparative study of these solids clearly demonstrate the higher catalytic activity at a given pH and temperature. Activation energies for the decomposition reaction of hydrogen peroxide on the surfaces of CuO and ZnO estimated from the Arrhenius plots were 57 KJ.mol/sup -1/ and 67 KJ.mol/sup -1/, respectively. (author)

  14. Hydrogen peroxide formation and decay in γ-irradiated clay water

    The mechanism of the radiolytic formation and disappearance of hydrogen peroxide in aerated clay water was studied. The yield of H2O2 formation in clay water in an air atmosphere is equal to 0.25 μmol J-1. When initially present in the solution, hydrogen peroxide disappears with a yield dependent upon the concentration and the dose rate. In both cases a steady state is reached dependent on the dose rate. In order to define more precisely the role of OH free radicals in this process, the reaction of these free radicals in clay water was studied by pulse radiolysis. As expected, OH is scavenged by different solutes, therefore, it cannot react with hydrogen peroxide. A kinetic scheme based upon these results is proposed. Using a minimal equation set (nine equations), it is possible to simulate the [H2O2] evolution with a very good accuracy, for doses going up to 20,000 Gy. It is also demonstrated that the reaction of H2 with OH does not occur in such conditions, which is consistent with the accumulation of dihydrogen during the radiolysis of ground water. (author)

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

    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. PMID:27211299

  16. Electrodeposition of Silver Nanoparticles on MWCNT Film Electrodes for Hydrogen Peroxide Sensing

    DING,Yan-Feng; JIN,Guan-Ping; YIN,Jun-Guang

    2007-01-01

    Silver (Ag) nanoparticles were directly electrodeposited on multi-walled carbon nanotubes (MWCNT) in AgNO3/LiNO3 containing EDTA (ethylenediaminetetraacetic acid). The structure and nature of the resulting Ag/MWNT composite were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD), and the distribution shape of Ag nanoparticles was found to be dependent on the presence of EDTA. The modified electrode showed excellent electrocatalytic activity to redox reaction of hydrogen peroxide and the mechanism of hydrogen peroxide was partly reversible procession with oxidation and reduction peaks at 0.77 and -0.83 V, respectively. The oxidation and reduction peak currents were linearly related to hydrogen peroxide concentration in the range of 1×10-6-3×10-4 and 1×10-8-7×10-4 mol·L-1 with correlation coefficients of 0.996 and 0.986, and 3s-detection limit of 9 × 10-7 and 7 × 10-9 mol·L-1.

  17. Comparison of chemiluminescence methods for analysis of hydrogen peroxide and hydroxyl radicals

    Pehrman, R.; Amme, M. (European Commission, Joint Research Centre, Institute for Transuranium Elements, Karlsruhe, (Germany)); Cachoir, C. (SCK.CEN, Waste and Disposal Unit., Mol (Belgium))

    2010-03-15

    Full text: Disposal of spent nuclear fuel in underground repositories is being considered in many countries and for this purpose understanding of behaviour of radiolysis products is required. To study the effects of alpha radiolysis products of water on oxidation and dissolution of actinides, a method to analyse those products is needed. Chemiluminescence is generally considered a simple, sensitive and reasonably selective method to detect reactive oxygen species on low concentrations. Concentrations of interest for both hydrogen peroxide and hydroxyl radicals are 10-6 to 10-9 M. The aim of this study is to compare various chemiluminescence methods for detecting hydrogen peroxide and hydroxyl radicals. Four methods to analyse hydrogen peroxide were chosen based on the estimated suitability for radiolysis experiments. Two of these use luminol, catalyzed by either mu-peroxidase or hemin, one uses 10-methyl-9-(p-formylphenyl) acridinium carboxylate trifluoromethanesulfonate and one potassium periodate. All methods were tested as batch systems in basic conditions. For hydroxyl radical detection luminophores tested were 3-hydroxyphthalic hydrazide (product of phthalic hydrazide and hydroxyl radical) and rutin. Both methods were tested as batch systems. The results are compared and the applicability of the methods for near-field dissolution studies is discussed. (author)

  18. Development of decomposition method of hydrogen peroxide in spent fuel pool

    From the viewpoint of the minimizing the corrosion of the spent fuel rods and structural material in the spent fuel pool, the ion exchange resins are generally used as one of purification system in order to keep water quality clean. Hydrogen peroxide generated by the radiolysis of water exists in the pool water and it accelerates the oxidation decomposition of the ion exchange resins and finally, it becomes the cause to shorten the resin life. To solve this problem, the application of Pd doped resins which can decompose hydrogen peroxide catalytically at the surface has been considered. It was confirmed by the cold test that Pd doped resins overlaid on the ion exchange resins decomposed hydrogen peroxide contained in the pool water and inhibited the oxidative degradation of the ion exchange resins. Based on the results, hot examination tests by using actual pool water in Tsuruga-2 were carried out from Jan. 2014 to Mar. 2014. We report the results of these tests. (author)

  19. Roles of RPS41 in Biofilm Formation, Virulence, and Hydrogen Peroxide Sensitivity in Candida albicans.

    Lu, Hui; Xiong, Juan; Shang, Qinghua; Jiang, Yuanying; Cao, Yingying

    2016-06-01

    In eukaryotes, loss of cytoplasmic ribosomal proteins (RPs) results in a reduced growth rate and other phenotypic defects. The ability to transition from a unicellular budding yeast to a filamentous form is very important for biofilm formation and virulence in Candida albicans. Our recent study found that loss of the RPS41 (C2_10620W_A) gene but not its paralog RPS42 (C1_01640W_A) resulted in altered growth and filamentation changes in C. albicans, so we hypothesized that the RPS41 gene should play important roles in virulence and biofilm formation in this pathogen. We found that both virulence and the ability to form biofilms were defective due to deletion of the RPS41 gene. We also found that loss of the RPS41 gene increased sensitivity to hydrogen peroxide, and that hydrogen peroxide induced the expression of the RPS41 gene in a wild-type strain. These results suggested that the RPS41 gene plays important roles in C. albicans biofilm formation, virulence, and susceptibility to hydrogen peroxide. PMID:26952720

  20. Measurement of the G values of hydrogen peroxide in the reactions of typical flavonoids with superoxide anion radicals. Pt.2

    γ irradiated rutin-, catechin-and baicalin-HCOONa aqueous solutions saturated with N2O:O2 = 4:1 were eluted through alumina columns and the G values of hydrogen peroxide generated in the solutions were measured. Different results from former works were obtained and the reasons of the difference were discussed. A precise method was established as follows: hydrogen peroxide should be separated from flavonoids by passing the flavonoids solution through alumina columns before the measurement and the amount of hydrogen peroxide generated from self-oxidation of the flavonoids should be deducted. The G values of hydrogen peroxide in γ irradiated rutin-, catechin- and baicalin- aqueous solution saturated with N2O:O2= 4:1 were determined to be 8.3 +- 0.2, 5.6 +- 0.2, and 7.8 +- 0.2, separately

  1. A Hydrogen Peroxide Biosensor Combined HRP Doped Polypyrrole with Ferrocene Modified Sol-gel Derived Composite Carbon Electrode

    2001-01-01

    A novel amperometric biosensor for the detection of hydrogen peroxide is described.The biosensor was constructed by electrodepositing HRP/PPy membrane on the surface of ferrocenecarboxylic acid mediated sol-gel derived composite carbon electrode. The biosensor gives response to hydrogen peroxide in a few seconds with detection limit of 5×l0-7 mol · L-1(based on signal: noise=3). Linear range is up to 0.2 mmol · L-1.

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

    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 was...... concentrations above 6 mg/L which is suitable for on-line monitoring of e.g. waste waters....

  3. Production of superoxide and hydrogen peroxide in medium used to culture Legionella pneumophila: catalytic decomposition by charcoal.

    Hoffman, P S; Pine, L; Bell, S.

    1983-01-01

    The difficulties associated with the growth of Legionella species in common laboratory media may be due to the sensitivity of these organisms to low levels of hydrogen peroxide and superoxide radicals. Exposure of yeast extract (YE) broth to fluorescent light generated superoxide radicals (3 microM/h) and hydrogen peroxide (16 microM/h). Autoclaved YE medium was more prone to photochemical oxidation than YE medium sterilized by filtration. Activated charcoals and, to a lesser extent, graphite...

  4. Detection of hydrogen peroxide vapor by use of manganese(IV) oxide as catalyst for calorimetric gas sensors

    Oberländer, Jan; Kirchner, Patrick; Boyen, Hans-Gerd; Schöning, Michael J.

    2014-01-01

    In this work, the catalyst manganese(IV) oxide (MnO2), of calorimetric gas sensors (to monitor the sterilization agent vaporized hydrogen peroxide) has been investigated in more detail. Chemical analyses by means of X-ray-induced photoelectron spectroscopy have been performed to unravel the surface chemistry prior and after exposure to hydrogen peroxide vapor at elevated temperature, as applied in the sterilization processes of beverage cartons. The surface characterization reveals a change i...

  5. Deletion of the sigB Gene in Bacillus cereus ATCC 14579 Leads to Hydrogen Peroxide Hyperresistance

    Schaik, van, G.; Zwietering, M.H.; Vos, de, W.M.; Abee, T.

    2005-01-01

    The sigB gene of Bacillus cereus ATCC 14579 encodes the alternative sigma factor σB. Deletion of sigB in B. cereus leads to hyperresistance to hydrogen peroxide. The expression of katA, which encodes one of the catalases of B. cereus, is upregulated in the sigB deletion mutant, and this may contribute to the hydrogen peroxide-resistant phenotype.

  6. Oxidative stress response of Inonotus obliquus induced by hydrogen peroxide.

    Zheng, Weifa; Zhao, Yanxia; Zhang, Meimei; Wei, Zhiwen; Miao, Kangjie; Sun, Weiguo

    2009-12-01

    While the medicinal fungus Inonotus obliquus produces polyphenols as one of its main metabolites in natural habitats, it accumulates less polyphenols under laboratory conditions. In this study we found that the continuous addition of 1 mM H(2)O(2) at a rate of 1.6 ml/h into a submerged culture of the fungus enhanced its production of mycelia, melanins, flavonoids and hispidin analogs (HA). Simultaneous exposure of the fungus to both H(2)O(2) and arbutin resulted in reduced production of mycelia, glycosylated flavonoids (GF) and HA, and inhibition of melanogenesis. However, superoxide dismutases (SOD) and catalase (CAT) activity were enhanced following the addition of H(2)O(2) or H(2)O(2) plus arbutin. The maximum levels of SOD and CAT activities reached 355.2 U/mg protein and 39.8 U/mg protein respectively in H(2)O(2)-added medium, and 264 U/mg protein and 35.9 U/mg protein respectively in H(2)O(2) plus arbutin medium. Thus, detoxification of H(2)O(2) is conducted mainly by polyphenols under normal physiological conditions, and by both polyphenols and antioxidant enzymes under oxidative stress when melanogenesis is inhibited. Although enhanced HA production occurred after melanogenesis inactivation, total extracellular polyphenol levels were reduced. These findings suggest that enzymatic activities convert superoxide to H(2)O(2), and non-enzymatic mechanisms are largely responsible for detoxifying H(2)O(2). Enhanced production of melanins is the most important non-enzymatic response of this fungus against oxidative stress. PMID:19184774

  7. Inhibition of hydrogen embrittlement of Ni-Ti superelastic alloy in acid fluoride solution by hydrogen peroxide addition.

    Yokoyama, Ken'ichi; Yazaki, Yushin; Sakai, Jun'ichi

    2011-09-01

    Inhibition of the hydrogen embrittlement of Ni-Ti superelastic alloy in an acidulated phosphate fluoride (APF) solution has been attempted by adding various amounts of H(2)O(2). In a 0.2% APF solution, hydrogen absorption is markedly inhibited by adding H(2)O(2), although corrosion is slightly enhanced by increasing the amount of added H(2)O(2). By adding a small amount of H(2)O(2) (0.001 M), in the early stage of immersion, hydrogen embrittlement is inhibited and corrosion is only slightly enhanced. Upon adding H(2)O(2), it appears that the dominant cathodic reactions change from hydrogen evolution to H(2)O(2) reduction reactions, or the surface conditions of the alloy are changed by H(2)O(2) with a high oxidation capability, thereby inhibiting hydrogen absorption. The present study clearly indicates that infinitesimal addition of H(2)O(2) into acid fluoride solutions is effective for the inhibition of the hydrogen embrittlement of the alloy. PMID:21630433

  8. Comparison efficiency of both sonochemical and sonochemical/hydrogen peroxide processes forcyanide removal from aqueous solutions

    Reza Shokohi

    2009-01-01

    Full Text Available (Received 5 October, 2009 ; Accepted 23 December, 2009AbstractBackground and purpose: Cyanide is a species of high toxicity that is found mostly in industrial effluents such as electroplating, metal mining, metallurgy and metal cleaning processes. Entrance of it to existing environment contains a hazardous to health. The purpose of this study was to compare efficiency of both sonochemical and sonochemical / hydrogen peroxide processes for cyanide removal from aqueous solutions.Materials and methods: This study has been used from a productive set of 500w power ultrasound waves in of two frequencies 35 kHz and 130 kHz. Experiments were performed with different initial ratio 1/1, 1/3 and 1/5 and at initial cyanide concentrations varying from 2.5 to 75 mg/L. in this study, Effects of parameters such as pH; time, initial cyanide concentration, hydrogen peroxide/ cyanide and frequency on removal efficiency of mention processes have been studied.Results: The results of the study showed that the maximum removal efficiency of cyanide had been achieved to 74% by sonochemical process at frequency of 130 kHz, at time of 90 min, at pH of 11, at initial cyanide concentration of 2.5 mg/l and with initial ratio of 1/5. However in similar condition, removal efficiency of cyanide had been achieved to 85% by sonochemical/ hydrogen peroxide process.Conclusion: The results of the study showed that rates of cyanide degradation under different conditions had always been quite low, and also the rate of cyanide degradation was first high but it was later substantially reduced. Results of the study showed that efficiency of sonochemical/hydrogen peroxide process is more than of sonochemical process for cyanide removal from aqueous solutions. Also removal efficiency of cyanide has direct relationship with pH, frequency, hydrogen peroxide and time; however, it has reverse relationship with cyanide concentration for process.J Mazand Univ Med Sci 2009; 19(73: 60-67 (Persian.

  9. Shear Bond Strength of Resin Bonded to Bleached Enamel Using Different Modified 35% Hydrogen Peroxides

    Moosavi H

    2015-12-01

    Full Text Available Statement of Problem: Bleaching systems with different concentrations and applications are widely used to improve the visual appearance of the teeth, but one of the complications of these materials is reduction of bond strength for immediately bonding to the bleached enamel. Objectives: The aim of this study was to evaluate the influence of using different modified hydrogen peroxide bleaching agents on the shear bond strength of composite resin bonded to the bleached enamel. Materials and Methods: Forty-eight sound extracted premolar teeth were collected, sectioned 1 mm below the CEJ to detach the root. The proximal surfaces of the teeth were flattened using diamond disks and silicon carbide papers to achieve flat homogeneous enamel surfaces without exposure to the dentin. The teeth were randomly divided into four groups as follows (n = 12: group 1: bleaching with 35% hydrogen peroxide gel; group 2: bleaching with 35% hydrogen peroxide gel contained (casein phosphopeptide-amorphous calcium phosphate (CPP-ACP; group 3: bleaching with 35% hydrogen peroxide gel combined with fluoride; and group 4: bleaching with 35% hydrogen peroxide applying one week before resin restoration placement. Composite resin, Clearfil AP-X (Kuraray, Tokyo, Japan, was bonded on each tooth in the mould (4 mm diameter × 3 mm height using Clearfil SE Bond (Kuraray, Tokyo, Japan. After 24 hours of storage and 1000 cycles of thermocycling, the shear bond strength of the specimens at a cross-head speed of 0.5 mm/min was measured in MPa. Data were analyzed using ANOVA and Tukey’s post-hoc test. Results: The minimum and maximum mean shear bond strength values were observed in groups 2 (15.82 ± 4.41 and 4 (21.00 ± 3.90, respectively. Multiple comparisons of groups revealed no significant differences among the groups except between group 4 and all the other groups. The most common type of failure was adhesive. Conclusions: Using modified bleaching agents decreased the bond

  10. Electric Response of Hydrogen Peroxide-doped Water Ices: an Analog Study for Positive Hole Currents in Rocks

    Stockburger, C. C.; Keller, C. T.; Gray, A.; Sornette, J.; Udom, A.; Cruikshank, D. P.; Freund, F.

    2013-12-01

    Hydrogen peroxide-doped water ices can be viewed an analog system to igneous and high-grade metamorphic rocks, which invariably contain peroxy defects, typically Si-OO-Si, and generate positive hole charge carriers when subjected to stress. By preparing pure water ice and hydrogen peroxide-doped water ices, freezing them to -80°C, allows us to control the concentration of peroxy defects (here hydrogen peroxide molecules) and study the electrical response, when the ices are subjected to stress. Blocks of pure water ice and hydrogen peroxide-doped water ices, -80°C, were prepared. Two methods to activate peroxy bonds were used: (i) stressing one end of rectangular blocks in a hydraulic press, (ii) subjecting one part of a 2-chamber plastic tray to intense ultrasound to create a gradient of activated charge carriers. In the hydraulic press experiments the pure water ice samples produced vanishingly small currents except for occasional transients, mostly negative, during fracturing of the ice. By contrast, hydrogen peroxide-doped water ices led to significant currents, consistently positive, flowing down the stress gradients. Using ultrasound as an activation method avoids fracturing. Therefore the results are much 'cleaner', not contaminated by hard-to-control fracture-induced currents. The positive sign of the currents suggests defect electrons, generated by the break-up of peroxy bonds of hydrogen peroxide molecules embedded in the ice structure, analogous to positive hole charge carriers that are stress-activated in rocks.

  11. Automatic dosage of hydrogen peroxide in solar photo-Fenton plants: development of a control strategy for efficiency enhancement.

    Ortega-Gómez, E; Moreno Úbeda, J C; Alvarez Hervás, J D; Casas López, J L; Santos-Juanes Jordá, L; Sánchez Pérez, J A

    2012-10-30

    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(2)O(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. PMID:22954603

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

    The present study attempts to use hydrogen peroxide solution to humidify Ca(OH)2 particles to enhance the absorption of SO2 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 SO2 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, SO2 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 SO2. 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 SO2 by spraying hydrogen peroxide solution to humidify Ca(OH)2 was elucidated on the basis of the experimental results.

  13. Generation of hydrogen peroxide from San Joaquin Valley particles in a cell-free solution

    Shen, H.; Barakat, A. I.; Anastasio, C.

    2011-01-01

    Epidemiological studies have shown a correlation between exposure to ambient particulate matter (PM) and adverse health effects. One proposed mechanism of PM-mediated health effects is the generation of reactive oxygen species (ROS) - e.g., superoxide (•O2-), hydrogen peroxide (HOOH), and hydroxyl radical (•OH) - followed by oxidative stress. There are very few quantitative, specific measures of individual ROS generated from PM, but this information would help to more quantitatively address the link between ROS and the health effects of PM. To address this gap, we quantified the generation of HOOH by PM collected at an urban (Fresno) and rural (Westside) site in the San Joaquin Valley (SJV) of California during summer and winter from 2006 to 2009. HOOH was quantified by HPLC after extracting the PM in a cell-free, phosphate-buffered saline (PBS) solution with or without 50 μM ascorbate (Asc). Our results show that the urban PM generally generates much more HOOH than the rural PM but that there is no apparent seasonal difference in HOOH generation. In nearly all of the samples the addition of a physiologically relevant concentration of Asc greatly enhances HOOH formation, but a few of the coarse PM samples were able to generate a considerable amount of HOOH in the absence of added Asc, indicating the presence of unknown reductants. Normalized by air volume, the fine PM (PM2.5) generally makes more HOOH than the corresponding coarse PM (PMcf, i.e., 2.5 to 10 μm), primarily because the mass concentration of PM2.5 is much higher than that of PMcf. However, normalized by PM mass, the coarse PM typically generates more HOOH than the fine PM. The amount of HOOH produced by SJV PM is reduced on average by (78 ± 15)% when the transition metal chelator desferoxamine (DSF) is added to the extraction solution, indicating that transition metals play a dominant role in HOOH generation. By measuring calibration curves of HOOH generation from copper, and quantifying copper

  14. Generation of hydrogen peroxide from San Joaquin Valley particles in a cell-free solution

    H. Shen

    2010-09-01

    Full Text Available Epidemiological studies have shown a correlation between exposure to ambient particulate matter (PM and adverse health effects. One proposed mechanism of PM-mediated health effects is the generation of reactive oxygen species (ROS – e.g., superoxide (•O2, hydrogen peroxide (HOOH, and hydroxyl radical (•OH – followed by oxidative stress. There are very few quantitative, specific measures of individual ROS generated from PM, but this information would help to more quantitatively address the link between ROS and the health effects of PM. To address this gap, we quantified the generation of HOOH by PM collected at an urban (Fresno and rural (Westside site in the San Joaquin Valley (SJV of California during summer and winter from 2006 to 2009. HOOH was quantified by HPLC after extracting the PM in a cell-free, phosphate-buffered saline (PBS solution with or without 50 μM ascorbate (Asc. Our results show that the urban PM generally generates much more HOOH than the rural PM but that there is no apparent seasonal difference in HOOH generation. In nearly all of the samples the addition of a physiologically relevant concentration of Asc greatly enhances HOOH formation, but a few of the coarse PM samples were able to generate a considerable amount of HOOH in the absence of added Asc, indicating the presence of unknown reductants. Normalized by air volume, the fine PM (PM2.5 generally makes more HOOH than the corresponding coarse PM (PMcf, i.e., 2.5 to 10 μm, primarily because the mass concentration of PM2.5 is much higher than that of PMcf. However, normalized by PM mass, the coarse PM typically generates more HOOH than the fine PM. The amount of HOOH produced by SJV PM is reduced on average by (78±15% when the transition metal chelator desferoxamine (DSF is added to the extraction solution, indicating that transition metals play a dominant role in HOOH generation. By

  15. Generation of hydrogen peroxide from San Joaquin Valley particles in a cell-free solution

    H. Shen

    2011-01-01

    Full Text Available Epidemiological studies have shown a correlation between exposure to ambient particulate matter (PM and adverse health effects. One proposed mechanism of PM-mediated health effects is the generation of reactive oxygen species (ROS – e.g., superoxide (O2, hydrogen peroxide (HOOH, and hydroxyl radical (OH – followed by oxidative stress. There are very few quantitative, specific measures of individual ROS generated from PM, but this information would help to more quantitatively address the link between ROS and the health effects of PM. To address this gap, we quantified the generation of HOOH by PM collected at an urban (Fresno and rural (Westside site in the San Joaquin Valley (SJV of California during summer and winter from 2006 to 2009. HOOH was quantified by HPLC after extracting the PM in a cell-free, phosphate-buffered saline (PBS solution with or without 50 μM ascorbate (Asc. Our results show that the urban PM generally generates much more HOOH than the rural PM but that there is no apparent seasonal difference in HOOH generation. In nearly all of the samples the addition of a physiologically relevant concentration of Asc greatly enhances HOOH formation, but a few of the coarse PM samples were able to generate a considerable amount of HOOH in the absence of added Asc, indicating the presence of unknown reductants. Normalized by air volume, the fine PM (PM2.5 generally makes more HOOH than the corresponding coarse PM (PMcf, i.e., 2.5 to 10 μm, primarily because the mass concentration of PM2.5 is much higher than that of PMcf. However, normalized by PM mass, the coarse PM typically generates more HOOH than the fine PM. The amount of HOOH produced by SJV PM is reduced on average by (78 ± 15% when the transition metal chelator desferoxamine (DSF is added to the extraction solution, indicating that transition metals play a dominant role in HOOH

  16. Aldehydes, hydrogen peroxide, and organic radicals as mediators of ozone toxicity

    Pryor, W.A.; Church, D.F. (Biodynamics Institute, Louisiana State University, Baton Rouge (United States))

    1991-01-01

    It is generally agreed that unsaturated fatty acids (UFA) are an important class of target molecule for reaction with ozone when polluted air is inhaled. Most discussions have implicated the UFA in cell membranes, but lung lining fluids also contain fatty acids that are from 20 to 40% unsaturated. Since UFA in lung lining fluids exist in a highly aquated environment, ozonation would be expected to produce aldehydes and hydrogen peroxide, rather than the Criegee ozonide. In agreement with this expectation, the authors find that ozonations of emulsions of fatty acids containing from one to four double bonds give one mole of H2O2 for each mole of ozone reacted. Ozonation of oleic acid emulsions and dioleoyl phosphatidyl choline gives similar results, with two moles of aldehydes and one mole of H2O2 formed per mole of ozone reacted. The net reaction that occurs when ozone reacts with pulmonary lipids is suggested to be given by equation 1. (formula: see text). From 5 to 10% yields of Criegee ozonides also appear to be formed. In addition, a direct reaction of unknown mechanism occurs between ozone and UFA in homogeneous organic solution, in homogeneous solutions in water, in aqueous emulsions, and in lipid bilayers to give organic radicals that can be spin trapped. These radicals are suggested to be responsible for initiating lipid peroxidation of polyunsaturated fatty acids. Thus, aldehydes, hydrogen peroxide, and directly produced organic radicals are suggested to be mediators of ozone-induced pathology.39 references.

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

    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.)

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

    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.

  19. Hydrogen peroxide detection with high specificity in living cells and inflamed tissues.

    Rong, Lei; Zhang, Chi; Lei, Qi; Hu, Ming-Ming; Feng, Jun; Shu, Hong-Bing; Liu, Yi; Zhang, Xian-Zheng

    2016-12-01

    Hydrogen peroxide (H2O2) detection in biological systems is of significant importance, which act as critical second messenger in fundamental biological processes. Here, we report on a chemoselective fluorescent naphthylimide peroxide probe (NPP) for the H2O2 detection in vitro and in vivo. NPP is a phenylboronic acid-caged chromophore that selectively responds to H2O2 through a self-immolate mechanism. NPP exhibited high sensitivity and selectivity to H2O2 with distinctive fluorescence change due to the excellent two-photon excitation property, which permits the facile detection of inflammation produced H2O2 and offers chance to monitor the inflammatory stages in diseased cells. PMID:27482463

  20. Hydrogen peroxide detection with high specificity in living cells and inflamed tissues

    Rong, Lei; Zhang, Chi; Lei, Qi; Hu, Ming-Ming; Feng, Jun; Shu, Hong-Bing; Liu, Yi; Zhang, Xian-Zheng

    2016-01-01

    Hydrogen peroxide (H2O2) detection in biological systems is of significant importance, which act as critical second messenger in fundamental biological processes. Here, we report on a chemoselective fluorescent naphthylimide peroxide probe (NPP) for the H2O2 detection in vitro and in vivo. NPP is a phenylboronic acid-caged chromophore that selectively responds to H2O2 through a self-immolate mechanism. NPP exhibited high sensitivity and selectivity to H2O2 with distinctive fluorescence change due to the excellent two-photon excitation property, which permits the facile detection of inflammation produced H2O2 and offers chance to monitor the inflammatory stages in diseased cells.

  1. Hydrogen peroxide

    The safety of fresh and fresh-cut produce available in salad-bar operations and supermarkets is a concern because of foodborne illness arising from consumption of fruits and vegetables that are surface contaminated with enteric pathogens. Field-packed produce are not generally washed because of the ...

  2. The effect of hydrogen peroxide on uranium oxide films on 316L stainless steel

    Highlights: • The first report of the presence of both UO2 and polymeric UO22+ in the same electrodeposited U oxide sample. • The action of H2O2 on electrodeposited U oxides is described using corrosion based concepts. • Electrodeposited U oxide freely dissolves at hydrogen peroxide concentrations <100 μmol dm−3. • At [H2O2] > 0.1 mmol dm−3 dissolution is inhibited by formation of a studtite passivation layer. • At [H2O2] ⩾ 1 mol dm−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 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

  3. Vibrational spectra and molecular dynamics of hydrogen peroxide molecules at quartz/water interfaces

    Lv, Ye-qing; Zheng, Shi-li; Wang, Shao-na; Yan, Wen-yi; Zhang, Yi; Du, Hao

    2016-06-01

    The influence of H2O2 on the water vibration at quartz interface was examined using sum-frequency generation (SFG) spectroscopy, and the effect of H2O2 concentration has been systematically studied. Further, the number density and radical distribution of water molecules, H2O2 molecules, and quartz surface silanol groups were calculated using molecular dynamics (MD) simulation to provide molecular level interpretation for the SFG spectra. It is concluded from this study that the hydrogen peroxide molecules prefers to donate H-bonds to the in-plane silanol groups rather than accepting H-bonds from out-of-plane silanol groups, as evidenced by the strengthening of the peak located at 3400 cm-1 assigned to "liquid-like" hydrogen-bonding network. The SFG results have been supported by the MD calculation results, which demonstrate that the relative intensity of the peak located at 3400 cm-1 to that of located at 3200 cm-1 increases monotonously with the increase in the number of hydrogen peroxide in the first hydration shell of silanol.

  4. Nanocomposite of Au Nanoparticles/Helical Carbon Nanofibers and Application in Hydrogen Peroxide Biosensor.

    Zhai, Mumu; Cui, Rongjing; Gu, Ning; Zhang, Genhua; Lin, Wang; Yu, Lingjun

    2015-06-01

    A combined sol-gel/hydrogen reduction method has been developed for the mass production of helical carbon nanofibers (HCNFs) by the pyrolysis of acetylene at 425 degrees C in the presence of NiO nanoparticles. The synthesized HCNFs were characterized with scanning electron microscopy (SEM), X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). The helical-structured carbon nanofibers have a large specific surface area and excellent biocompatibility. A novel enzymatic hydrogen peroxide sensor was then successfully fabricated based on the nanocomposites containing HCNFs and gold nanoparticles (AuNPs). The results indicated that the Au/HCNFs nanocomposites exhibited excellent electrocatalytic activity to the reduction of H2O2, offering a wide linear range from 1.0 μM to 3157 μM with a detection limit as low as 0.46 μM. The apparent Michaelis-Menten constant of the biosensor was 0.61 mM. The as-fabricated biosensor showed a rapid and sensitive amperometric response to hydrogen peroxide with acceptable preparation reproducibility and excellent stability. Because of their low cost and high stability, these novel HCNFs represent seem to be a kind of promising biomaterial and may find wide new applications in scopes such as biocatalysis, immunoassay, environmental monitoring and so on. PMID:26369097

  5. Evaluation of the permeability of modified cellulose acetate propionate membranes for use in biosensors based on hydrogen peroxide detection

    Guiomar, A. Jorge; Stephen D. Evans; Guthrie, James

    2001-01-01

    Phase inversion cellulose acetate propionate membranes showed lowpermeability to hydrogen peroxide aqueous solutions. Their permeability wasincreased by alkaline hydrolysis of the ester linking units. However, thepermeability remained lower than that of an unsubstituted cellulose membrane.The inclusion of hydroxypropyl cellulose in the membrane formulation, followedby an alkaline hydrolysis step, increased permeability to hydrogen peroxideaqueous solutions to 29% of that of an unsubstituted c...

  6. Induction of eosinophil apoptosis by hydrogen peroxide promotes the resolution of allergic inflammation.

    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 C S; Coutinho, D de Sá; 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 gp91(phox-/-) 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

  7. Seasonal variations of hydrogen peroxide and water vapor on Mars: Further indications of heterogeneous chemistry

    Encrenaz, T.; Greathouse, T. K.; Lefèvre, F.; Montmessin, F.; Forget, F.; Fouchet, T.; DeWitt, C.; Richter, M. J.; Lacy, J. H.; Bézard, B.; Atreya, S. K.

    2015-06-01

    We have completed our seasonal monitoring of hydrogen peroxide and water vapor on Mars using ground-based thermal imaging spectroscopy, by observing the planet in March 2014, when water vapor is maximum, and July 2014, when, according to photochemical models, hydrogen peroxide is expected to be maximum. Data have been obtained with the Texas Echelon Cross Echelle Spectrograph (TEXES) mounted at the 3 m-Infrared Telescope Facility (IRTF) at Maunakea Observatory. Maps of HDO and H2O2 have been obtained using line depth ratios of weak transitions of HDO and H2O2 divided by CO2. The retrieved maps of H2O2 are in good agreement with predictions including a chemical transport model, for both the March data (maximum water vapor) and the July data (maximum hydrogen peroxide). The retrieved maps of HDO are compared with simulations by Montmessin et al. (2005, J. Geophys. Res., 110, 03006) and H2O maps are inferred assuming a mean martian D/H ratio of 5 times the terrestrial value. For regions of maximum values of H2O and H2O2, we derive, for March 1 2014 (Ls = 96°), H2O2 = 20+/-7 ppbv, HDO = 450 +/-75 ppbv (45 +/-8 pr-nm), and for July 3, 2014 (Ls = 156°), H2O2 = 30+/-7 ppbv, HDO = 375+/-70 ppbv (22+/-3 pr-nm). In addition, the new observations are compared with LMD global climate model results and we favor simulations of H2O2 including heterogeneous reactions on water-ice clouds.

  8. Isothermal Microcalorimetric Evaluation of Compatibility of Proposed Injector Materials with High-Test Hydrogen Peroxide Propellant

    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.

  9. Intracellular signaling by diffusion: can waves of hydrogen peroxide transmit intracellular information in plant cells?

    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 of...... the physical and biochemical conditions in plant cells. As model system, we use a H(2)O(2) signal originating at the plasma membrane (PM) and spreading through the cytosol. We consider two maximally simple types of signals, isolated pulses and harmonic oscillations. First we consider the basic limits...

  10. Intracellular signaling by diffusion: can waves of hydrogen peroxide transmit intracellular information in plant cells?

    Vestergaard, Christian Lyngby; Flyvbjerg, Henrik; Møller, Ian Max

    2012-01-01

    Amplitude- and frequency-modulated waves of Ca2+ 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 of the...... physical and biochemical conditions in plant cells. As model system, we use a H2O2 signal originating at the plasma membrane (PM) and spreading through the cytosol. We consider two maximally simple types of signals, isolated pulses and harmonic oscillations. First we consider the basic limits on such...

  11. A rare case of portal vein gas: accidental hydrogen peroxide ingestion

    Zengin, Suat; Al, Behcet; Genç, Sinan; Yarbil, Pınar; Yilmaz, Demet Ari; Gulsen, Murat Taner

    2012-01-01

    Hydrogen peroxide (H2O2) is a colourless and odourless liquid with oxidant characteristics used for various purposes. Whereas in lower concentrations (3%), H2O2 is used as a disinfectant in home cleaning products and wound care, in higher concentrations (35%) it is used in textile and paper industry as a bleaching agent and is diluted for use in lightening hair dyes. Like other caustic substances, direct injuries may develop if H2O2 is swallowed and systemic air embolisms may occur due to the...

  12. Hydrogen peroxide is involved in cGMP modulating the lateral root development of Arabidopsis thaliana

    Li, Jisjeng; Jia, Honglei

    2013-01-01

    3′,5′-cyclic guanosine monophosphate (cGMP) and hydrogen peroxide (H2O2) function as the important signaling molecule which promote the lateral root development of Arabidopsis thaliana. In this study, interestingly, application of 8-Br-cGMP (the membrane permeable cGMP analog) promoted the endogenous H2O2 production. In addition, the decrease of endogenous H2O2 also inhibited the effect of cGMP on the lateral root development. Thus, H2O2 maybe act as a downstream signaling of cGMP molecule wh...

  13. Inactivation of possible microorganism food contaminants on packaging foils using nonthermal plasma and hydrogen peroxide

    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

  14. Low doses of ionizing radiation and hydrogen peroxide stimulate plant growth

    The present study shows that low-dose oxidative stress induced by ionizing radiation (10-20 cGy) and hydrogen peroxide (1-100 pmol per litre) stimulates germination of seeds and growth of sprouts and roots. The growth of seedlings can be stimulated by treatment of seeds as well as seedlings but in the latter case it needs lower doses. The stimulation effect is observed in a narrow dose interval which is the same for the plant species studied: barley, wheat, pea, maize and melon

  15. Direct Colorimetric Detection of Hydrogen Peroxide Using 4-Nitrophenyl Boronic Acid or Its Pinacol Ester

    Gregory Su; Yibin Wei; Maolin Guo

    2011-01-01

    A colorimetric method for the direct determination of hydrogen peroxide in aqueous solution is described. H2O2 stoichiometrically converts 4-nitrophenyl boronic acid or 4-nitrophenyl boronic acid pinacol ester into 4-nitrophenol, which can be quantified by measuring the absorption at 400 nm in neutral or basic media. The reactions proceed fast under basic conditions and complete in 2 minutes to at pH 11 and 80?C. The linear range for the colorimetric method extends beyond 1.0 to 40 µM H2O2, a...

  16. ExoMol line lists XV: A new hot line list for hydrogen peroxide

    Al-Refaie, Ahmed F.; Polyansky, Oleg L.; Ovsyannikov, Roman I.; Tennyson, Jonathan; Yurchenko, Sergei N.

    2016-01-01

    A computed line list for hydrogen peroxide, H$_2{}^{16}$O$_2$, applicable to temperatures up to $T=1250$~K is presented. A semi-empirical high accuracy potential energy surface is constructed and used with an {\\it ab initio} dipole moment surface as input TROVE to compute 7.5 million rotational-vibrational states and around 20 billion transitions with associated Einstein-$A$ coefficients for rotational excitations up to $J=85$. The resulting APTY line list is complete for wavenumbers below 6~...

  17. The analgesic efficacy of xylazine and dipyrone in hydrogen peroxide-induced oxidative stress in chicks

    Y. J. Mousa; Mohammad, F. K.

    2012-01-01

    The effect of oxidative stress–induced by hydrogen peroxide (H2O2) on the analgesic effect of xylazine and dipyrone in 7-14 days old chicks was studied, compared with the control group that given plane tap water. H2O2, 0.5 % in water, induced oxidative stress in chicks by significantly lowering glutathione, rising malondialdehyde in plasma, whole brain during the day 7th, 10th, 14th of chicks old in comparison with the control group. The analgesic median effective doses (ED50) of xylazine and...

  18. Photocatalytic Degradation of Pesticides in Natural Water: Effect of Hydrogen Peroxide

    Natividad Miguel; Ormad, María P.; Rosa Mosteo; José L. Ovelleiro

    2012-01-01

    The aim of this paper is to evaluate the effectiveness of photocatalytic treatment with titanium dioxide in the degradation of 44 organic pesticides analyzed systematically in the Ebro river basin (Spain). The effect of the addition of hydrogen peroxide in this treatment is studied, and a monitoring of effectiveness of photocatalytic processes is carried out by measurements of physical-chemical parameters of water. The application of photocatalytic treatment with 1 g L−1 of TiO2 during 30 min...

  19. Screen-printable silver nanoparticulate-based inks for the electrocatalysis of hydrogen peroxide

    Goodison, Alan; Killard, Anthony J.; Morrin, Aoife

    2013-01-01

    The detection of hydrogen peroxide has been shown to be very important in recent years due to its relevant role in many industrial applications as well as biological reactions. We are interested in it as a quantitative marker for oxidase-based biosensor applications where it is produced when substrate (e.g., glucose, cholesterol) is catalysed by its respective oxidase enzyme. Previously, a commercial silver flake-based screen-printing ink (PF-410, Acheson®), when treated with surfactant and s...

  20. Tricholoma matsutake fruit bodies secrete hydrogen peroxide as a potent inhibitor of fungal growth.

    Takakura, Yoshimitsu

    2015-06-01

    Tricholoma matsutake is an ectomycorrhizal fungus that dominates the microbial communities in the soil of pine and spruce forests. The mycorrhizas of this fungus have antimicrobial activity, although factors responsible for the antimicrobial activity have not been fully elucidated. The present study shows that fruit bodies of T. matsutake secreted hydrogen peroxide (H2O2), which was produced by pyranose oxidase, and that the H2O2 thus secreted strongly inhibited the growth of mycelia of the phytopathological fungus Rhizoctonia solani. These findings suggest that fruit bodies of T. matsutake have antifungal activity and that the pyranose oxidase plays an important role in the antifungal activity. PMID:25803209

  1. Inactivation of possible microorganism food contaminants on packaging foils using nonthermal plasma and hydrogen peroxide

    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.

  2. Environmentally Benign Oxidation of Some Organic Sulfides with 34% Hydrogen Peroxide Catalyzed by Simple Heteropolyoxometalates

    TAYEBEE,Reza; ALIZADEH,Moharnmad Hassan

    2007-01-01

    An environmentally benign oxygenation protocol was developed for selective oxidation of some types of aromatic and aliphatic sulfides in good to excellent yields utilizing 34% hydrogen peroxide catalyzed by simple heteropolyoxometalates in normal drinking water at room temperature. The catalysts could be recovered and reused for at least seven reaction cycles under the described reaction conditions without considerable loss of reactivity. This procedure introduced a new insight into the use of simple heteropolyanions as recoverable catalysts for the oxidation of organic sulfides by an environmentally acceptable protocol.

  3. 8-Alkylcoumarins from the Fruits of Cnidium monnieri Protect against Hydrogen Peroxide Induced Oxidative Stress Damage

    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.

  4. Salinity-Gradient Energy Driven Microbial Electrosynthesis of Hydrogen Peroxide from Oxygen Reduction

    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...... be used to generated renewable eleltrical energy to replace the external power supply[2]. Operational parameters such as air flow rate, pH, cathodic potential, flow rate of high and low concentration NaCl solution in RED were investigated as to improve the H2O2 yield. The optimal parameters for H2O2...

  5. Inactivation of possible microorganism food contaminants on packaging foils using nonthermal plasma and hydrogen peroxide

    Scholtz, V.; Khun, J.; Soušková, H.; Čeřovský, M.

    2015-07-01

    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. Electrochemically Reduced Graphene Oxide-nafion/Au Nanoparticle Modified Electrode for Hydrogen Peroxide Sensing

    Yajie Lv; Fang Wang; Hui Zhu; Xiaorong Zou; Cheng-an Tao; Jianfang Wang

    2016-01-01

    n this paper, a non-enzymatic hydrogen peroxide (H2O2) sensor, based on Au nanoparticles (AuNPs) electrodepos‐ ited on an electrochemically reduced graphene oxide(ER‐ GO)-Nafion modified glass carbon electrode (GCE), was reported. The graphene oxide-(GO-)Nafion nanocompo‐ sites were first assembled on the GCE surface to produce a GO-Nafion electrode. GO was then electrochemically reduced to produce an ERGO-Nafion modified GCE (to be subsequently denoted as GCE/ERGO-Nafion). Afterwards, AuNPs ...

  7. Green tea polyphenols protect spinal cord neurons against hydrogen peroxide-induced oxidative stress

    Jianbo Zhao; Shiqiang Fang; Yajiang Yuan; Zhanpeng Guo; Jinhao Zeng; Yue Guo; Peifu Tang; Xifan Mei

    2014-01-01

    Green tea polyphenols are strong antioxidants and can reduce free radical damage. To investigate their neuroprotective potential, we induced oxidative damage in spinal cord neurons using hy-drogen peroxide, and applied different concentrations (50-200 µg/mL) of green tea polyphenol to the cell medium for 24 hours. Measurements of superoxide dismutase activity, malondial-dehyde content, and expression of apoptosis-related genes and proteins revealed that green tea polyphenol effectively alleviated oxidative stress. Our results indicate that green tea polyphenols play a protective role in spinal cord neurons under oxidative stress.

  8. Visualization of Endogenous and Exogenous Hydrogen Peroxide Using A Lysosome-Targetable Fluorescent Probe

    Kim, Dabin; Kim, Gyoungmi; Nam, Sang-Jip; Yin, Jun; Yoon, Juyoung

    2015-02-01

    Reactive oxygen species (ROS) play crucial roles in diverse physiological processes; therefore, the efficient detection of ROS is very crucial. In this study, we report a boronate-based hydrogen peroxide (H2O2) probe having naphthalimide fluorophore. This probe also contained a morpholine moiety as a directing group for lysosome. The recognition property indicated that the probe exhibited high selectivity towards H2O2 not only in the solution but also in the living cells. Furthermore, it was used to monitor the level of endogenous and exogenous H2O2. These results support that the probe can function as an efficient indicator to detect H2O2.

  9. Development and application of photofragmentation laser-induced fluorescence for visualization of hydrogen peroxides

    Johansson, Olof

    2011-01-01

    The work presented in this thesis is mainly motivated by the need for an optical diagnostic technique which can be used to visualize hydrogen peroxide (H2O2) in its gas phase. Due to the lack of bound electronic states, H2O2 cannot be detected using laser-induced fluorescence based on electronic excitation. Absorption in the ultraviolet leads to photodissociation. Thus a technique called photofragmentation laser-induced fluorescence (PF-LIF) has been developed and applied. It is a pump-probe ...

  10. Effect of Hydrogen Peroxide on Immersion Challenge of Rainbow Trout Fry with Flavobacterium psychrophilum

    Henriksen, Maya Maria Mihályi; Madsen, Lone; Dalsgaard, Inger

    2013-01-01

    An experimental model for immersion challenge of rainbow trout fry (Oncorhynchus mykiss) with Flavobacterium psychrophilum, the causative agent of rainbow trout fry syndrome and bacterial cold water disease was established in the present study. Although injection-based infection models are reliable...... 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...

  11. The E-loop Is Involved in Hydrogen Peroxide Formation by the NADPH Oxidase Nox4*

    Takac, Ina; Schröder, Katrin; Zhang, Leilei; Lardy, Bernard; Anilkumar, Narayana; Lambeth, J. David; Shah, Ajay M.; Morel, Francoise; Brandes, Ralf P.

    2011-01-01

    In contrast to the NADPH oxidases Nox1 and Nox2, which generate superoxide (O2˙̄), Nox4 produces hydrogen peroxide (H2O2). We constructed chimeric proteins and mutants to address the protein region that specifies which reactive oxygen species is produced. Reactive oxygen species were measured with luminol/horseradish peroxidase and Amplex Red for H2O2 versus L-012 and cytochrome c for O2˙̄. The third extracytosolic loop (E-loop) of Nox4 is 28 amino acids longer than that of Nox1 or Nox2. Dele...

  12. Hydrogen peroxide scavenging regulates germination ability during wheat (Triticum aestivum L.) seed maturation

    Ishibashi, Yushi; Yamamoto, Kouhei; Tawaratsumida, Tomoya; Yuasa, Takashi; Iwaya-Inoue, Mari

    2008-01-01

    Hydrogen peroxide (H2O2) promotes seed germination of cereal plants and ascorbic acid which acts as antioxidant suppresses the germination of wheat seeds, but the role of H2O2 scavenging on germination during seed maturation has not been demonstrated. We investigated relationship of germination, ascorbate, H2O2 scavenging enzymes and sensitivity to ascorbic acid (AsA) maturing seeds of two typical wheat (Triticum aestivum L.) cultivars, cvs. Shirogane-Komugi and Norin61. Shirogane-Komugi had ...

  13. Degradation of 2,4-dichlorophenoxyacetic acid in water by ozone-hydrogen peroxide process

    YU Ying-hui; MA Jun; HOU Yan-jun

    2006-01-01

    This study reports an investigation into the degradation of 2,4-dichlorophenoxyacetic acid in bubble contactor column by O3/H2O2 process, which is widely used as a principal advanced oxidation process. The degradation of 2,4-dichlorophenoxyacetic acid was studied under different H2O2/O3 molar ratio and pH value. Meanwhile, TOC removal was investigated both in distilled water and tap water. The influences of ozone transfer and consumed hydrogen peroxide were also discussed. The degradation products and oxidation intermediates were identified by GC-MS and LC-MS. A possible reaction mechanism was thus proposed.

  14. MODELING HYDROGEN PEROXIDE BLEACHING OF SODA PULP FROM OIL-PALM EMPTY FRUIT BUNCHES

    Ana Ferrer; Antonio Rosal; Cristina Valls; Blanca Roncero; Alejandro Rodriguez

    2011-01-01

    The influence of the variables soda (0.5-3.0%), hydrogen peroxide (1.0-6.0%) and time (1-5 h) in the bleaching of soda pulp of empty fruit bunches (EFB) from oil-palm, on the properties of bleached pulps, was studied. Polynomial and neural fuzzy models reproduced the results of brightness, kappa number, and viscosity of the pulps with errors less than 10%. By the simulation of the bleaching of pulp, using the polynomial and neural fuzzy models, it was possible to find optimal values of operat...

  15. Hydrogen Peroxide Biosensor Based on the Direct Electrochemistry of Myoglobin Immobilized in Poly-3-Hydroxybutyrate Film

    Xiang Ma

    2005-01-01

    Full Text Available Direct electrochemistry of myoglobin (Mb was observed in a stable film composed of a natural lipid polymer (poly-3-hydroxybutyrate and Mb, the film of which was modified on a pyrolytic graphite electrode. The apparent formal potential of Mb was at about -260 mV in an acetate buffer solution with pH 5.0. Moreover, Mb in the polymer film exhibited catalytic activity towards the reduction of hydrogen peroxide (H2O2. Consequently, an unmediated biosensor for H2O2 was prepared with a linear range from 1.0×10-7 to 4.0×10-4 M.

  16. Shape transformation of silver nanospheres to silver nanoplates induced by redox reaction of hydrogen peroxide

    Parnklang, Tewarak; Lamlua, Banjongsak; Gatemala, Harnchana; Thammacharoen, Chuchaat [Department of Chemistry, Faculty of Science, Chulalongkorn University, 254 Phyathai Road, Patumwan, Bangkok 10330 (Thailand); Kuimalee, Surasak [Industrial Chemistry and Textile Technology Programme, Faculty of Science, Maejo University, Chiang Mai 50290 (Thailand); Lohwongwatana, Boonrat [Metallurgical Engineering Department, Faculty of Engineering, Chulalongkorn University, 254 Phyathai Road, Patumwan, Bangkok 10330 (Thailand); Ekgasit, Sanong, E-mail: sanong.e@chula.ac.th [Department of Chemistry, Faculty of Science, Chulalongkorn University, 254 Phyathai Road, Patumwan, Bangkok 10330 (Thailand)

    2015-03-01

    In this paper we demonstrate a simple and rapid shape transformation of silver nanospheres (AgNSs) to silver nanoplates (AgNPls) using the oxidation and reduction capabilities of hydrogen peroxide. AgNPls having tunable surface plasmon resonance across the visible region with average size of 40–100 nm and thickness of 10–15 nm can be fabricated within 2 min simply by adding H{sub 2}O{sub 2} into a colloid of AgNSs with average particle size of 7 nm. The efficiency of H{sub 2}O{sub 2} as a shape-transforming agent depends strongly on its concentration, pH of the AgNS colloid, and the employed stabilizers. H{sub 2}O{sub 2} oxidizes AgNSs to silver ions while concertedly reduces silver ions to silver atom necessary for the growth of AgNPls. The shape transformation reaction was conducted at a relatively low concentration of H{sub 2}O{sub 2} in order to minimize the oxidative dissolution while facilitating kinetically controlled growth of AgNPls under a near neutral pH. Polyvinyl-pyrrolidone is an effective steric stabilizer preventing aggregation while assisting the growth of AgNPls. Trisodium citrate inhibits the formation of AgNPls under the H{sub 2}O{sub 2} reduction as it forms a stable complex with silver ions capable of withstanding the weakly reducing power of H{sub 2}O{sub 2}. After a complete consumption of AgNSs, large nanoplates grows with an expense of smaller nanoplates. The growth continues until H{sub 2}O{sub 2} is exhausted. A high concentration H{sub 2}O{sub 2} promotes catalytic decomposition of H{sub 2}O{sub 2} on the surface of AgNSs and oxidative dissolution of AgNSs without a formation of AgNPls. - Graphical abstract: Proposed mechanism for the shape transformation of AgNSs to AgNPls induced by the oxidation/reduction of H{sub 2}O{sub 2}. - Highlights: • Rapid shape transformation of silver nanospheres to nanoplates by H{sub 2}O{sub 2}. • Structural change completes in 2 min with a yellow-to-blue color change. • Selective fabrication of

  17. Sliding discharges in steam: effects of dielectric surface and hydrocarbon additives on hydrogen, oxygen and hydrogen peroxide generation

    A sliding surface discharge was formed on a dielectric layer in steam at ∼100 °C and atmospheric pressure. The material properties and the thickness of the dielectric layer were found to strongly affect the energy deposition into the plasma. With a 0.32 cm thick dielectric the energy deposition was 1.4 times greater than with a 0.48 cm thick dielectric, and with window glass it was 1.3 times greater than with Macor of the same thickness. Product gases were H2 (73 ± 4%) and O2 (27 ± 1%), and H2O2 accumulated in the condensed water up to 0.4 g l−1. The energy yield for hydrogen was 1.2 ± 0.1 g H2 kWh−1 and independent of the input power and thickness or material of the dielectric. However, for hydrogen peroxide the energy yield, which varied between 0.61 and 3.2 g H2O2 kWh−1, was found to depend strongly on the thickness and material of the dielectric. The addition of benzene to the steam increased the energy efficiency of hydrogen to 2.3 g kWh−1, and decreased oxygen and hydrogen peroxide by about 3 and 6 times, respectively. It also caused the deposition of phenol and polymer-like layers on the dielectric. The results are explained on the basis of reactions of H and OH radicals adsorbed on the surface and/or in gas phase. (paper)

  18. Micromorphology and microhardness of enamel after treatment with home-use bleaching agents containing 10% carbamide peroxide and 7.5% hydrogen peroxide

    Robson Tetsuo Sasaki

    2009-12-01

    Full Text Available OBJECTIVE: The purpose of this study was to assess the effect of home-use bleaching agents containing 10% carbamide peroxide and 7.5% hydrogen peroxide on enamel microhardness and surface micromorphology. MATERIAL AND METHODS: Enamel slabs (n=10 received the bleaching agents for 1 h/day and remained in artificial saliva solution for 23 h/day, during a total period of 21 days. Control group was composed of enamel slabs that were not subjected to treatment with the agents and were maintained in artificial saliva solution. Microhardness tests were performed before treatment application, 21 days of treatment and 14 days after the end of treatment. Scanning electron microscopy analyses were performed after 14 days after the end of bleaching treatment by 3 calibrated observers who attributed scores. RESULTS: The Tukey's test (α=0.05 showed no significant differences in microhardness values among bleaching agents, at 21 days of treatment and a significant increase in microhardness for different agents after 14 days from the end of treatment. Fisher's exact test showed differences in micromorphology of enamel between control and experimental groups (p=0.0342. CONCLUSIONS: Bleaching agents containing 10% carbamide peroxide and 7.5% hydrogen peroxide may change surface micromorphology of enamel, although no changes in microhardness were observed.

  19. Leaching performance of imidazolium based ionic liquids in the presence of hydrogen peroxide for recovery of metals from brass waste

    Kilicarslan, Ayfer; Saridede, Muhlis N.

    2016-01-01

    The application of ionic liquids (ILs), 1-methylimidazolium hydrogen sulfate (HmimHSO4), 1-ethyl-3-methylimidazolium hydrogen sulfate (HmimHSO4) and 1-butyl-3-methylimidazolium chloride (BmimCl) as leaching agents was investigated in the leaching of copper and zinc from brass waste in the presence of an oxidant, hydrogen peroxide (H2O2). Factors that affect copper and zinc dissolution rates such as ionic liquid concentration, time and temperature were investigated. The results indicated that ...

  20. Molecular dynamics of hydrogen peroxide in liquid water using a combined quantum/classical force field

    Molecular dynamics simulations using a combined quantum/classical force field have been carried out to investigate the properties of hydrogen peroxide in aqueous solution. Radial distribution functions exhibit close similarities with those obtained for the OH radical. They show that H2O2 is a better proton donor than H2O but a weaker proton acceptor. Solvent effects modify the O-H bonds, which are weakened and elongated by 0.02 A. The HOOH dihedral angle decreases by 11 deg. and the dipole moment increases by 0.8 D. The O-O bond length and bond order do not change much. Fluctuations of the frontier orbital energies are analyzed in detail as a function of both, the HOOH geometry and the solvent configuration. Hydrogen-bonds with solvent molecules appear to have an opposite influence depending on their donor/acceptor character. Interconversion between energy minima always proceeds through a transoid transition state

  1. The effect of hydrogen peroxide on uranium oxide films on 316L stainless steel

    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.

  2. Hydrogen Peroxide Stimulates the Ca2+-activated Big-Conductance K Channels (BK) Through cGMP Signaling Pathway in Cultured Human Endothelial Cells

    Dong, De-Li; Yue, Peng; Yang, Bao-Feng; Wang, Wen-Hui

    2008-01-01

    We used the whole cell patch-clamp technique to examine the effect of hydrogen peroxide (H2O2) on the Ca2+-activated BK channels in human endothelial cells. We confirmed the previous finding that a 200 pS BK channel activity was detected when the cell membrane potential was clamped at 50 mV. Application of H2O2 or adding glucose oxidase (GO) stimulated BK channels. The stimulatory effect of H2O2 and GO was absent in cells treated with ebselen, a scavenger of reactive oxygen species (ROS). To ...

  3. The periodontal pathogen Porphyromonas gingivalis harnesses the chemistry of the mu-oxo bishaem of iron protoporphyrin IX to protect against hydrogen peroxide.

    Smalley, J W; Birss, A J; Silver, J

    2000-02-01

    The major haem component in the black pigment of Porphyromonas gingivalis is the mu-oxo bishaem of iron protoporphyrin IX and formation and cell-surface binding of this haem species is proposed as an extracellular buffer against reactive oxidants [Smalley, J.W. et al. (1998) Biochem. J. 331, 681-685]. P. gingivalis cells grown in the presence of the mu-oxo bishaem were protected against H(2)O(2) compared to control cells grown without it. When added to the growth medium, soluble mu-oxo bishaem inactivated H(2)O(2) and supported cell growth. Cells carrying a surface layer of mu-oxo bishaem were less susceptible to peroxidation by H(2)O(2). Cell-surface haems were slowly destroyed during reaction with H(2)O(2). Binding of mu-oxo bishaem by P. gingivalis may aid survival during neutrophil attack through inactivation of hydrogen peroxide. PMID:10650220

  4. Molecular and Cellular Effects of Hydrogen Peroxide on Human Lung Cancer Cells: Potential Therapeutic Implications

    2016-01-01

    Lung cancer has a very high mortality-to-incidence ratio, representing one of the main causes of cancer mortality worldwide. Therefore, new treatment strategies are urgently needed. Several diseases including lung cancer have been associated with the action of reactive oxygen species (ROS) from which hydrogen peroxide (H2O2) is one of the most studied. Despite the fact that H2O2 may have opposite effects on cell proliferation depending on the concentration and cell type, it triggers several antiproliferative responses. H2O2 produces both nuclear and mitochondrial DNA lesions, increases the expression of cell adhesion molecules, and increases p53 activity and other transcription factors orchestrating cancer cell death. In addition, H2O2 facilitates the endocytosis of oligonucleotides, affects membrane proteins, induces calcium release, and decreases cancer cell migration and invasion. Furthermore, the MAPK pathway and the expression of genes related to inflammation including interleukins, TNF-α, and NF-κB are also affected by H2O2. Herein, we will summarize the main effects of hydrogen peroxide on human lung cancer leading to suggesting it as a potential therapeutic tool to fight this disease. Because of the multimechanistic nature of this molecule, novel therapeutic approaches for lung cancer based on the use of H2O2 may help to decrease the mortality from this malignancy. PMID:27375834

  5. Aromatic hydrocarbon degradation in hydrogen peroxide- and nitrate-amended microcosms

    Fifty microcosms were constructed using aquifer materials from a former coal gasification site and divided into four groups: poisoned control, nutrient-free control, hydrogen peroxide-amended, and nitrate-amended microcosms. Each microcosm contained site soil and groundwater in a 1.2-L glass media bottle. When depleted, hydrogen peroxide and sodium nitrate were injected into the microcosms. Microcosms were periodically sacrificed for analysis of polycyclic aromatic hydrocarbons (PAHs); monocyclic aromatic hydrocarbons (benzene, toluene, ethylbenzene, and xylenes [BTEX]); total petroleum hydrocarbons (TPH); and heterotrophic plate counts (HPCs). BTEX and two- and three-ringed PAHs were degraded in microcosms receiving electron-acceptor additions compared to poisoned controls. Four-, five-, and six-ringed PAHs were not significantly degraded during this study. Except in poisoned controls, significant amounts of dissolved oxygen (DO) or nitrate were utilized, and microbial populations increased by 3 to 5 orders of magnitude compared to site soils used to assemble the microcosms (i.e., baseline samples)

  6. Protection of Salvianolic Acid B for Human Endothelial Cells Against Hydrogen Peroxide-Induced Oxidative Damage

    ZHANG Jungang; ZHAO Guangrong; LIU Jinling; JI Xiangwu

    2009-01-01

    Salvianolic acid B(Sal B) is an active component of traditional Chinese medicine Salvia miltiorrhiza and is used to treat vascular diseases. To better understand its mechanism, the antioxidant capacities of Sal B was evaluated with human endothelial cells under oxidative stress. Human endothelial cells were pretreated with Sal B for 12 h followed by hydrogen peroxide for another 12 h. Production of reactive oxygen species (ROS), activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX), and concentration of glu-tathione were measured: Protective effect of Sal B on the endothelial cells from hydrogen peroxide-induced damage ' was observed, and ROS production in the cells was found significantly inhibited. Sal B remarkably enhanced the activities of antioxidant enzymes SOD, CAT and GPX. Furthermore, Sal B up-regulated the intracellular glutathione concentration. The results indicate that Sal B protected endothelial cells from oxidative stress by improving the redox status of the cells through enhancing the antioxidant enzyme activities and increasing the reductive glutathione concentration after the oxidative challenge.

  7. Efficiency of hydrogen peroxide production by ac capillary discharge in water solution

    Efficiency of hydrogen peroxide production by an ac driven underwater capillary discharge was investigated quantitatively. The concentration of formed hydrogen peroxide was measured by a colorimetric method using a specific reaction between H2O2 and a titanium reagent. The amount of formed H2O2 increases linearly during the first hour of the discharge duration. The initial rate and corresponding total energy yield of H2O2 formation by the capillary discharge were determined for initial electrical conductivity of aqueous solution in the range of 100-500 μS cm-1 and average applied power in the range 30-90 W. It comes out that the total energy yield of H2O2 formation, derived from the initial rate of H2O2 formation and the average applied power, increases linearly with average applied power and that solution conductivity has only a negligible effect on the energy yield. A maximum total energy yield of H2O2 formation of 0.9 g kWh-1 was obtained for a 500 μS cm-1 aqueous solution

  8. Amperometric hydrogen peroxide biosensor based on cobalt ferrite–chitosan nanocomposite

    A novel H2O2 biosensor based on horseradish peroxidase (HRP) immobilized into CoFe2O4–chitosan nanocomposite has been developed for the detection of hydrogen peroxide. The nanocomposite films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). HRP has been entrapped into CoFe2O4–chitosan nanocomposite film and the immobilized enzyme could retain its bioactivity. This biosensor exhibited a fast amperometric response to hydrogen peroxide. The linear range for H2O2 determination was from 3 × 10−2 to 8 mM, with a detection limit of 2 × 10−3 mM based on S/N = 3. The response time of the biosensor was 4 s. The effects of the pH and the temperature of the immobilized HRP electrode were also studied. - Highlights: ► HRP biosensor based on CoFe2O4–chitosan nanocomposite has been developed for H2O2 detection. ► The biosensor seems to be simple to prepare, fast to respond, inexpensive and sensitive. ► The biosensor had high sensitivity, good repeatability, reusability and long term stability.

  9. Enhanced electrochemical reduction of hydrogen peroxide at metallic electrodes modified with surfactant and salt

    The enhanced electrocatalytic reduction of hydrogen peroxide brought about by the modification of noble metal electrode surfaces with a modification of surfactant and salt was assessed. A range of electrodes composed of Ag, Au and Pt, either as continuous metal films or as particulate metallic pastes were employed. Several surfactants (cationic, anionic and non-ionic), as well as a range of Group I metal halides with differing cations were all investigated to assess the contribution of these components to the reduction of hydrogen peroxide at −0.1 V vs. Ag/AgCl. It was shown that on silver paste electrodes, all surfactant/salt combinations enhanced the observed catalysis. However, the degree to which they did this appears related to the critical micellar concentration of the surfactant, the size of the Group I metal ion and the optimum formation of lamellar structures formed by the surfactant/salt combination. Metallic electrodes showed less enhancement of catalysis over particulate paste electrodes. In addition, higher grade metallic surfaces showed poorer enhancements in catalysis which may relate to the extent of surface defects amenable to surface modification, as observed by electron microscopy. Silver paste electrodes modified with dodecylbenzene sulphonic acid/KCl exhibited a catalytic rate of 5.47 × 10−2 AM−1 cm−2, which was between 2- and 4-fold less than that observed on equivalent Pt electrodes.

  10. Surface modification of ZnO film by hydrogen peroxide solution

    Tsai, Chia-Hung; Wang, Wei-Chin; Jenq, Feng-Lin; Liu, Chien-Chih; Hung, Chen-I.; Houng, Mau-Phon

    2008-09-01

    The effect of hydrogen peroxide (H2O2) treatment on the microstructure and luminescent properties of ZnO thin films has been investigated. Governed by high-resolution transmission electron microscopy and selected-area electron diffraction patterns, the oxygen radicals dissociated from H2O2 solution at room temperature and substantially changed the polycrystalline ZnO film into an insulator. In addition, the photoluminescence spectra showed that H2O2 solution had nearly no effect on the intensity of ultraviolet emission, whereas it significantly enhanced the intensity of deep-level emission. These observations strongly reveal the fact that the oxygen radicals penetrating into a ZnO film are reasonably speculated to occupy the interstitial sites to form oxygen interstitials Oi or fill the Zn vacancies to form antisite oxygen OZn defects. Because of these extra defects involved, an enhancement of the green light luminescence is significantly promoted in our ZnO samples after handling with H2O2 solution. Based on the characteristics mentioned above, our hydrogen peroxide solution treated ZnO film has the potential for applying to the light-emitting diode with metal-insulator-semiconductor structure.

  11. Au/CeO{sub 2}-chitosan composite film for hydrogen peroxide sensing

    Zhang Wei [Key Laboratory of Medical Diagnostics, Ministry of Education, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016 (China); Xie Guoming, E-mail: guomingxie@cqmu.edu.cn [Key Laboratory of Medical Diagnostics, Ministry of Education, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016 (China); Li Shenfeng; Lu Lingsong; Liu Bei [Key Laboratory of Medical Diagnostics, Ministry of Education, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016 (China)

    2012-08-01

    Au nanoparticles (AuNPs) were in situ synthesized at the cerium dioxide nanoparticles (CeO{sub 2}NPs)-chitosan (CS) composite film by one-step direct chemical reduction, and the resulting Au/CeO{sub 2}-CS composite were further modified for enzyme immobilization and hydrogen peroxide (H{sub 2}O{sub 2}) biosensing. Transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), UV-vis spectra and electrochemical techniques have been utilized for characterization of the prepared composite. The stepwise assembly process and electrochemical performances of the biosensor were characterized by means of cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and typical amperometric response (i-t). The Au/CeO{sub 2}-CS composite exhibited good conductibility and biocompatibility, and the developed biosensor exhibited excellent response to hydrogen peroxide in the linear range of 0.05-2.5 mM (r = 0.998) with the detection limit of 7 {mu}M (S/N = 3). Moreover, the biosensor presented high affinity (K{sub m}{sup app}=1.93mM), good reproducibility and storage stability. All these results demonstrate that the Au/CeO{sub 2}-CS composite film can provide a promising biointerface for the biosensor designs and other biological applications.

  12. Amperometric Biosensor for Hydrogen Peroxide Based on Electrodeposited Sub-micrometer Gold Modified Glassy Carbon Electrode

    WANG,Shu-Qing(王树青); CHEN,Jun(陈峻); LIN,Xiang-Qin(林祥钦)

    2004-01-01

    A new type of hydrogen peroxide amperometric biosensor was fabricated based on electrochemically deposited sub-micrometer Au particles(sm-Au)on a glassy carbon electrode(GCE).Electrochemical deposition condition was optimized for obtaining uniformly distributed sub-micrometer sized Au array on the electrode surface.The hydrogen peroxide sensor was fabricated by adsorbing phenothiazine methylene blue(MB)molecules on the surface of sm-Au and covering a cross-linked horseradish peroxidase(HRP)layer,labeled as HRP/MB/sm-Au/GCE.The characteristics of this biosensor were evaluated with respect to applied potential and pH.The amperometric response of the sensor was linear to the H2O2 concentration over a wide range of 9.9×10-6-1.11×10-2 mol/L.A detection limit(s/n=3)of 3.0×10-6 mol/L H2O2 was estimated for a sampled chronoamperometric detection at 1.5 min after potential step of 200 to-400 mV vs.SCE.The immobilized MB molecules shuttled electrons at(=0.77 and an apparent electron transfer rate constant of =0.053 s-1.Interference of ascorbic acid,dopamine and uric acid was investigated.This sensor has very good stability and reproducibility for long-term use.

  13. Amperometric hydrogen peroxide biosensor based on cobalt ferrite-chitosan nanocomposite

    Yard Latin-Small-Letter-Dotless-I mc Latin-Small-Letter-Dotless-I , Feyza S.; Senel, Mehmet, E-mail: msenel@fatih.edu.tr; Baykal, Abduelhadi

    2012-02-01

    A novel H{sub 2}O{sub 2} biosensor based on horseradish peroxidase (HRP) immobilized into CoFe{sub 2}O{sub 4}-chitosan nanocomposite has been developed for the detection of hydrogen peroxide. The nanocomposite films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). HRP has been entrapped into CoFe{sub 2}O{sub 4}-chitosan nanocomposite film and the immobilized enzyme could retain its bioactivity. This biosensor exhibited a fast amperometric response to hydrogen peroxide. The linear range for H{sub 2}O{sub 2} determination was from 3 Multiplication-Sign 10{sup -2} to 8 mM, with a detection limit of 2 Multiplication-Sign 10{sup -3} mM based on S/N = 3. The response time of the biosensor was 4 s. The effects of the pH and the temperature of the immobilized HRP electrode were also studied. - Highlights: Black-Right-Pointing-Pointer HRP biosensor based on CoFe{sub 2}O{sub 4}-chitosan nanocomposite has been developed for H{sub 2}O{sub 2} detection. Black-Right-Pointing-Pointer The biosensor seems to be simple to prepare, fast to respond, inexpensive and sensitive. Black-Right-Pointing-Pointer The biosensor had high sensitivity, good repeatability, reusability and long term stability.

  14. Role of vanadium and pyridine in heteropolycompounds for selective oxidation of alcohols with hydrogen peroxide

    Valeria Palermo; Paula I Villabrille; Patricia G Vázquez; Carmen V Cáceres; Pietro Tundo; Gustavo P Romanelli

    2013-11-01

    This study describes the application of heteropolyacids H3PMo12O40,H4SiMo12O40, H4PMo11VO40, H5PMo10V2O40, H9PMo6V6O40, and a hybrid pyridine-modified heteropolyacid with Keggin structure for selective oxidation of alcohols to ketones or aldehydes using aqueous hydrogen peroxide and acetonitrile as solvent. Performance of these different catalysts in 1-phenylethanol oxidation was studied. Influence of reaction temperature, amount of catalyst and hydrogen peroxide and reaction time on the yield of acetophenone was investigated to obtain optimal reaction conditions. Oxidation ability of the catalyst depended on the number of vanadium atoms present in the Keggin ion and to a lesser extent on pyridine substitution in the Keggin secondary structure. In order to explore the applicability of the method for selective oxidation of alcohols to ketones or aldehydes, various alcohols were investigated according to the general procedure using hybrid pyridine-modified heteropolyacid.

  15. Degradation of chitosan by gamma ray with presence of hydrogen peroxide

    Mahmud, Maznah; Naziri, Muhammad Ihsan; Yacob, Norzita; Talip, Norhashidah; Abdullah, Zahid

    2014-02-01

    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 (H2O2), 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 H2O2 enhanced the degradation rate of chitosan even at very low irradiation dose. Homogenous degradation also occurred during treatment with H2O2based 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.

  16. Solar energy conversion by green microalgae: a photosystem for hydrogen peroxide production.

    de la Rosa, F F; Montes, O; Galván, F

    2001-09-20

    A photosystem for solar energy conversion, comprised of a culture of green microalgae supplemented with methyl viologen, is proposed. The capture of solar energy is based on the Mehler reaction. The reduction of methyl viologen by the photosynthetic apparatus and its subsequent reoxidation by oxygen produces hydrogen peroxide. This is a rich-energy compound that can be used as a nonpollutant and efficient fuel. Four different species of green microalgae, Chlamydomonas reinhardtii (21gr) C. reinhardtii (CW15), Chlorella fusca, and Monoraphidium braunii, were tested as a possible biocatalyst. Each species presented a different efficiency level in the transformation of energy. Azide was an efficient inhibitor of the hydrogen peroxide scavenging system while maintaining photosynthetic activity of the microalgae, and thus significantly increasing the production of the photosystem. The strain C. reinhardtii (21gr), among the species studied, was the most efficient with an initial production rate of 185 micromol H(2)O(2)/h x mg Chl and reaching a maximum of 42.5 micromol H(2)O(2)/mg Chl when assayed in the presence of azide inhibitor. PMID:11494222

  17. Ozone and hydrogen peroxide applications for disinfection by-products control in drinking water

    A great interest has been developed during the last years for ozone in drinking water treatments thanks to its strong oxidant and disinfectant power and for its efficiency in disinfection by-products (DBPs) precursors removal. However ozonization produces some specific DBPs, such as aldehydes and ketones; moreover, the presence of bromide in raw water engages ozone in a complex cycle in which both organic bromide and inorganic bromate are end products. In this paper the combination of hydrogen peroxide with ozone (known as peroxone process) and the ozone alone process were experimented on one surface water coming from the lake of Brugneto (Genova) in order to investigate bromate formation and trihalomethanes precursors removal during the oxidation process. The results show that the advanced peroxone process can be applied for bromate reduction (about 30-40%) with better results in comparison with the ozone alone process, while no advantages are shown for THMs precursors removal. The addition of in-line filtration step after pre-oxidation improves both bromate and THMs precursors removal, particularly with increasing hydrogen peroxide/ozone ratio in the oxidation step

  18. Cyanobacterial and microcystins dynamics following the application of hydrogen peroxide to waste stabilisation ponds

    Barrington, D. J.; Ghadouani, A.; Ivey, G. N.

    2013-06-01

    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.

  19. Evaluation of cotton-fabric bleaching using hydrogen peroxide and Blue LED

    de Oliveira, Bruno P.; Moriyama, Lilian T.; Bagnato, Vanderlei S.

    2015-06-01

    The raw cotton production requires multiple steps being one of them the removal of impurities acquired during previous processes. This procedure is widely used by textile industries around the world and is called bleaching. The raw cotton is composed by cellulosic and non-cellulosic materials like waxes, pectins and oils, which are responsible for its characteristic yellowish color. The bleaching process aims to remove the non-cellulosic materials concentration in the fabric, increasing its whiteness degree. The most used bleaching method utilizes a bath in an alkali solution of hydrogen peroxide, stabilizers and buffer solutions under high temperature. In the present study we evaluated the possibility of using a blue illumination for the bleaching process. We used blue LEDs (450 nm) to illuminate an acid hydrogen peroxide solution at room temperature. The samples treated by this method were compared with the conventional bleaching process through a colorimetric analysis and by a multiple comparison visual inspection by volunteers. The samples were also studied by a tensile test in order to verify the integrity of the cloth after bleaching. The results of fabric visual inspection and colorimetric analysis showed a small advantage for the sample treated by the standard method. The tensile test showed an increasing on the yield strength of the cloth after blue light bleaching. The presented method has great applicability potential due to the similar results compared to the standard method, with relative low cost and reduced production of chemical waste.

  20. Effects of hydrogen peroxide feeding strategies on the photochemical degradation of polyvinyl alcohol.

    Hamad, Dina; Dhib, Ramdhane; Mehrvar, Mehrab

    2016-11-01

    The performance of batch and fed-batch photoreactors with that of continuous photoreactor for the treatment of aqueous polyvinyl alcohol (PVA) solutions is compared. Hydrogen peroxide feeding strategies, residence time, and [H2O2]/[PVA] mass ratio are examined for their impacts on the molecular weight distribution (MWD) of PVA and the total organic carbon (TOC) removal. The results prove that a continuous addition of H2O2 during the degradation reaction ensures the utilization of the produced radicals to minimize the oxidant consumption and maximize the TOC removal and the PVA degradation in a short irradiation time. Also, the MWD of PVA is found to be bimodal and shifted towards lower molecular weights with small shoulder peak indicating a progressive disappearance of the higher molecular weight fractions that is in accordance with the random chains scission mechanism. Besides, the hydrogen peroxide feeding strategies are found to have a great effect on the reduction in H2O2 residuals in the effluent. PMID:27088453

  1. Degradation of chitosan by gamma ray with presence of hydrogen peroxide

    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 (H2O2), 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 H2O2 enhanced the degradation rate of chitosan even at very low irradiation dose. Homogenous degradation also occurred during treatment with H2O2based 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

  2. Degradation of chitosan by gamma ray with presence of hydrogen peroxide

    Full-text: 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 (H2O2), 1 % - 5 %. These chitosan-water mixtures were irradiated at 6 kGy, 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 H2O2 enhanced the degradation rate of chitosan even at very low irradiation dose. Homogenous degradation also occurred during treatment with H2O2 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. (author)

  3. Melatonin protects skin keratinocyte from hydrogen peroxide-mediated cell death via the SIRT1 pathway.

    Lee, Ju-Hee; Moon, Ji-Hong; Nazim, Uddin Md; Lee, You-Jin; Seol, Jae-Won; Eo, Seong-Kug; Lee, John-Hwa; Park, Sang-Youel

    2016-03-15

    Melatonin (N-acetyl-5-methoxytryptamine), which is primarily synthesized in and secreted from the pineal gland, plays a pivotal role in cell proliferation as well as in the regulation of cell metastasis and cell survival in a diverse range of cells. The aim of this study is to investigate protection effect of melatonin on H2O2-induced cell damage and the mechanisms of melatonin in human keratinocytes. Hydrogen peroxide dose-dependently induced cell damages in human keratinocytes and co-treatment of melatonin protected the keratinocytes against H2O2-induced cell damage. Melatonin treatment activated the autophagy flux signals, which were identified by the decreased levels of p62 protein. Inhibition of autophagy flux via an autophagy inhibitor and ATG5 siRNA technique blocked the protective effects of melatonin against H2O2-induced cell death in human keratinocytes. And we found the inhibition of sirt1 using sirtinol and sirt1 siRNA reversed the protective effects of melatonin and induces the autophagy process in H2O2-treated cells. This is the first report demonstrating that autophagy flux activated by melatonin protects human keratinocytes through sirt1 pathway against hydrogen peroxide-induced damages. And this study also suggest that melatonin could potentially be utilized as a therapeutic agent in skin disease. PMID:26918354

  4. Melatonin protects skin keratinocyte from hydrogen peroxide-mediated cell death via the SIRT1 pathway

    Lee, Ju-Hee; Moon, Ji-Hong; Nazim, Uddin MD.; Lee, You-Jin; Seol, Jae-Won; Eo, Seong-Kug; Lee, John-Hwa; Park, Sang-Youel

    2016-01-01

    Melatonin (N-acetyl-5-methoxytryptamine), which is primarily synthesized in and secreted from the pineal gland, plays a pivotal role in cell proliferation as well as in the regulation of cell metastasis and cell survival in a diverse range of cells. The aim of this study is to investigate protection effect of melatonin on H2O2-induced cell damage and the mechanisms of melatonin in human keratinocytes. Hydrogen peroxide dose-dependently induced cell damages in human keratinocytes and co-treatment of melatonin protected the keratinocytes against H2O2-induced cell damage. Melatonin treatment activated the autophagy flux signals, which were identified by the decreased levels of p62 protein. Inhibition of autophagy flux via an autophagy inhibitor and ATG5 siRNA technique blocked the protective effects of melatonin against H2O2-induced cell death in human keratinocytes. And we found the inhibition of sirt1 using sirtinol and sirt1 siRNA reversed the protective effects of melatonin and induces the autophagy process in H2O2-treated cells. This is the first report demonstrating that autophagy flux activated by melatonin protects human keratinocytes through sirt1 pathway against hydrogen peroxide-induced damages. And this study also suggest that melatonin could potentially be utilized as a therapeutic agent in skin disease. PMID:26918354

  5. Exhaled breath condensate pH and hydrogen peroxide as non-invasive markers for asthma

    Objective was to estimate the predictive value of exhaled breath condensate (EBC) hydrogen peroxide (H2O2) concentration and pH as non-invasive markers in asthma. Fifty patients with unstable, steroid naive atopic asthma were included in this study, 25 with persistent asthma. Asthma diagnosis was according to the National Heart Lung and Blood Institute guidelines for the diagnosis and management of asthma. Forced expiratory volume in one second (FEV1) was measured by computerized spirometry. The EBC H2O2 assay was carried out using the colorimetric assay. The study was conducted from January to December 2005 in the Asthma and Allergy Center, Tikrit, Iraq. The EBC H2O2 concentration was higher in the asthmatic group (0.91mol) as compared with the control (0.23 mol). There was inverse correlation between EBC H2O2 concentration and FEV1 predicted percent for asthmatic patients. The mean EBC pH was lower in the asthmatic than the control group. There was a positive correlation between EBC pH and FEV 1 predicted percent for asthmatic patients. There was an inverse correlation between EBC H2O2 concentration and pH for all asthmatic patients, intermittent, and persistent asthmatic group. Exhaled breath condensate hydrogen peroxide concentration and pH was a good non-invasive marker for asthma, whether it was with a persistent or intermittent course. (author)

  6. Study of the hydrogen peroxide bleaching agent effects on bovine enamel using X-ray fluorescence

    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)

  7. Yield of Ozone, Nitrite Nitrogen and Hydrogen Peroxide Versus Discharge Parameter Using APPJ Under Water

    Chen, Bingyan; Zhu, Changping; Fei, Juntao; He, Xiang; Yin, Cheng; Wang, Yuan; Gao, Ying; Jiang, Yongfeng; Wen, Wen; Chen, Longwei

    2016-03-01

    Discharge plasma in and in contact with water can be accompanied with ultraviolet radiation and electron impact, thus can generate hydroxyl radicals, ozone, nitrite nitrogen and hydrogen peroxide. In this paper, a non-equilibrium plasma processing system was established by means of an atmospheric pressure plasma jet immersed in water. The hydroxyl intensities and discharge energy waveforms were tested. The results show that the positive and negative discharge energy peaks were asymmetric, where the positive discharge energy peak was greater than the negative one. Meanwhile, the yield of ozone and nitrite nitrogen was enhanced with the increase of both the treatment time and the discharge energy. Moreover, the pH value of treated water was reduced rapidly and maintained at a lower level. The residual concentration of hydrogen peroxide in APPJ treated water was kept at a low level. Additionally, both the efficiency energy ratio of the yield of ozone and nitrite nitrogen and that of the removal of p-nitrophenol increased as a function of discharge energy and discharge voltage. The experimental results were fully analyzed and the chemical reaction equations and the physical processes of discharges in water were given. supported by National Natural Science Foundation of China (Nos. 11274092, 11404092, 61401146), the Nantong Science and Technology Project, Nantong, China (No. BK2014024), the Open Project of Jiangsu Province Key Laboratory of Environmental Engineering, Nanjing, China (No. KF2014001), and the Fundamental Research Funds for the Central Universities of China (No. 2014B11414)

  8. Paper-based membraneless hydrogen peroxide fuel cell prepared by micro-fabrication

    Mousavi Ehteshami, Seyyed Mohsen; Asadnia, Mohsen; Tan, Swee Ngin; Chan, Siew Hwa

    2016-01-01

    A paper-based membraneless single-compartment hydrogen peroxide power source prepared by micro-electromechanical systems (MEMS) technology is reported. The cell utilizes hydrogen peroxide as both fuel and oxidant in a low volume cell fabricated on paper. The fabrication method used is a simple method where precise, small-sized patterns are produced which include the hydrophilic paper bounded by hydrophobic resin. Open circuit potentials of 0.61 V and 0.32 V are achieved for the cells fabricated with Prussian Blue as the cathode and aluminium/nickel as the anode materials, respectively. The power produced by the cells is 0.81 mW cm-2 at 0.26 V and 0.38 mW cm-2 at 0.14 V, respectively, even after the cell is bent or distorted. Such a fuel cell provides an easily fabricated, environmentally friendly, flexible and cost saving power source. The cell may be integrated within a self-sustained diagnostic system to provide the on-demand power for future bio-sensing applications.

  9. MODELING HYDROGEN PEROXIDE BLEACHING OF SODA PULP FROM OIL-PALM EMPTY FRUIT BUNCHES

    Ana Ferrer

    2011-04-01

    Full Text Available The influence of the variables soda (0.5-3.0%, hydrogen peroxide (1.0-6.0% and time (1-5 h in the bleaching of soda pulp of empty fruit bunches (EFB from oil-palm, on the properties of bleached pulps, was studied. Polynomial and neural fuzzy models reproduced the results of brightness, kappa number, and viscosity of the pulps with errors less than 10%. By the simulation of the bleaching of pulp, using the polynomial and neural fuzzy models, it was possible to find optimal values of operating variables, so that the properties of bleached pulps differed only slightly from their best values and yet it was possible to save chemical reagents, energy, and plant size, operating with lower values of operating variables. Thus, operating with 1.13% soda concentration and 2.25% hydrogen peroxide concentration for 3 hours, a pulp with a brightness of 75.1% (8.1% below the maximum and a viscosity of 740 mL/g (10.4% less than the maximum value, was obtained.

  10. Mg(OH2-BASED HYDROGEN PEROXIDE BLEACHING OF CMP PULPS AT HIGH CONSISTENCY

    Pedram Fatehi

    2011-11-01

    Full Text Available The objective of this study was to investigate the bleaching performance of a Mg(OH2-based hydrogen peroxide process at a high consistency. In this work, an industrially produced chemimechanical pulp (CMP was bleached via Mg(OH2- or NaOH-based hydrogen peroxide processes at 10% and 25% consistencies. The results showed that the pulp bleached under the conditions of 1.5% Mg(OH2 and 3% H2O2 at 25% consistency had a similar brightness to, a lower yellowness index, and a higher opacity than the pulp produced under the conditions of 2.1% NaOH, 3% Na2SiO3, and 3% H2O2 at the same consistency. The temperature (70 ºC and time (150 min of the bleaching were the same for both processes. Under the conditions stated above, the Mg(OH2-based process had a higher yield than the NaOH-based process did. The bleaching effluent of the Mg(OH2-based process had a higher residual H2O2, but a lower Chemical Oxygen Demand (COD load and turbidity, compared with that of the NaOH-based process. However, the strength properties and water retention value (WRV of the pulp bleached via the Mg(OH2-based process were lower, while its bulk was higher than those of the pulp bleached via the NaOH-based process.

  11. Three-dimensional electrode microbial fuel cell for hydrogen peroxide synthesis coupled to wastewater treatment

    Chen, Jia-yi; Li, Nan; Zhao, Lin

    2014-05-01

    A three-dimensional electrode bioelectrochemical system for the cathodic production of hydrogen peroxide and the simultaneous treatment of wastewater is investigated. Three types of three-dimensional electrodes - activated carbon particle electrodes (ACPE), carbon black particle electrodes (CBPE) and graphite particle electrodes (GPE) - are made of activated carbon (AC), carbon black (CB) and graphite powders respectively with polytetrafluoroethene (PTFE) as the binder. The MFC using the GPE is shown to perform best for catalyzing H2O2 production, while the MFCs equipped with the CBPE and the ACPE achieve a 17-18% higher power output but a 2.5-4.4% lower H2O2 yield, due to the further cathodic reduction of H2O2. Furthermore, a relatively high current in the system is demonstrated to have a positive impact on both cathodic H2O2 generation and anodic organic degradation for each MFC. At an external resistance of 20 Ω, the MFC using the GPE achieves the H2O2 generation of 196.50 mg L-1 and 84% COD removal in 24 h, with Coulombic efficiency, Faradic efficiency and COD conversion efficiency of 29%, 70%, and 20%, respectively. This study shows that MFC with carbon three-dimensional electrode is a cost-effective energy-saving bioelectrochemical system for the simultaneous production of hydrogen peroxide and removal of COD.

  12. Radiation-induced degradation of an epoxy thermoset supported by hydrogen peroxide

    Epoxy resin was decomposed applying two complementary treatments, namely (1) soaking up with 30% aqueous solution of hydrogen peroxide and (2) exposure of the swelled material to ionizing radiation in air atmosphere over doses up to 1000 kGy. The phase transition characteristic determined by the DSC technique revealed that both factors, swelling with oxidizing agent and irradiation applied sequentially induce in the resin deep structural changes resulting in the rise of two new exothermic transitions assigned to hydrogen peroxide decomposition and resin oxidation. The flexural stress at break measurements confirmed significant influence of H2O2 on the mechanical properties of the irradiated material which, under applied conditions, is efficiently decayed via oxidative degradation. On the basis of results obtained by EPR spectroscopy chemical mechanism of the radiation induced degradation was proposed. - Highlights: • Mechanism of the radiation induced degradation of epoxy resin was proposed. • Epoxy thermoset swelled with H2O2 is radiation susceptible. • Radiation treatment followed by H2O2 swelling can be applied for resin recycling

  13. Characterization of hydrogen peroxide-resistant Acinetobacter species isolated during the Mars Phoenix spacecraft assembly.

    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. PMID:25243569

  14. [Influence of cadmium chloride and hydrogen peroxide on the content of phosphoinositides in isolated hepatocytes of rats].

    Borikov, A Iu; Kaliman, P A

    2004-01-01

    Influence of cadmium chloride and hydrogen peroxide on the processes of lipid peroxidation and contents of polyphosphoinositides in isolated hepatocytes of rats was studied. It is shown that incubation of the cells with cadmium chloride or hydrogen peroxide already in 15 min results in the reinforcement of lipid peroxidation and increase of contents of phosphatidylinositol and phosphatidylinositoldiphosphate. Variations of the basal level of the latter, as is well known, plays an important messenger role. In case of more long incubation (60 min) one can observe the significant accumulation of intermediate and final products of lipid peroxidation, while the content of phosphatidylinositol and phosphatidylinositoldiphosphate did not differ from the control, but the content of phosphatidylinositolphosphate was increased. Changes in the content of separate fraction of polyphosphoinositides in the presence of cadmium chloride and hydrogen peroxide were similar. Allowing for all that it is, possible to draw a conclusion that the mechanism of cadmium influence on the content of polyphosphoinositides is based on its ability to cause development of the oxidative stress. PMID:19621747

  15. Immobilization of redox mediators on functionalized carbon nanotube: A material for chemical sensor fabrication and amperometric determination of hydrogen peroxide

    D R Shobha Jeykumari; S Senthil Kumar; S Sriman Narayanan

    2005-10-01

    Chemical functionalization of single-walled carbon nanotubes with redox mediators, namely, toluidine blue and thionin have been carried out and the performance of graphite electrode modified with functionalized carbon nanotubes is described. Mechanical immobilization of functionalized single-walled nanotube (SWNT) on graphite electrode was achieved by gently rubbing the electrode surface on carbon nanotubes supported on a glass slide. The electrochemical behaviour of the modified electrodes was investigated by cyclic voltammetry. The SWNT-modified electrodes showed excellent electrocatalytic effect for the reduction of hydrogen peroxide. A decrease in overvoltage was observed as well as an enhanced peak current compared to a bare graphite electrode for the reduction of hydrogen peroxide. The catalytic current was found to be directly proportional to the amount of hydrogen peroxide taken.

  16. Core-shell Au/Ag nanoparticles embedded in silicate sol-gel network for sensor application towards hydrogen peroxide

    Shanmugam Manivannan; Ramasamy Ramaraj

    2009-09-01

    The electrocatalytic activity of core-shell Au100-Ag ( = 15, 27, 46, and 60) bimetallic nanoparticles embedded in methyl functionalized silicate MTMOS network towards the reduction of hydrogen peroxide was investigated by using cyclic voltammetry and chronoamperometric techniques. Core-shell Au/Ag bimetallic nanoparticles were characterized by absorption spectra and HRTEM. The MTMOS silicate sol-gel embedded Au73Ag27 core-shell nanoparticles modified electrode showed better synergistic electrocatalytic effect towards the reduction of hydrogen peroxide when compared to monometal MTMOS-Aunps and MTMOS-Agnps modified electrodes. These modified electrodes were studied without immobilizing any enzyme in the MTMOS sol-gel matrix. The present study highlights the influence of molar composition of Ag nanoparticles in the Au/Ag bimetallic composition towards the electrocatalytic reduction and sensing of hydrogen peroxide in comparison to monometal Au and Ag nanoparticles.

  17. Kinetics of the decomposition and the estimation of the stability of 10% aqueous and non-aqueous hydrogen peroxide solutions

    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.

  18. Automatic dosage of hydrogen peroxide in solar photo-Fenton plants: Development of a control strategy for efficiency enhancement

    Highlights: ► Dissolved oxygen monitoring is used for automatic dosage of H2O2 in photo-Fenton. ► PI with anti-windup minimises H2O2 consumption. ► The H2O2 consumption was reduced up to 50% with respect to manual addition strategies. ► Appropriate H2O2 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 H2O2 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.

  19. Automatic dosage of hydrogen peroxide in solar photo-Fenton plants: Development of a control strategy for efficiency enhancement

    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.

  20. Chronic toxicity of hydrogen peroxide to Daphnia magna in a continuous exposure, flow-through test system

    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 hydrogen peroxide for 21??days. Hydrogen peroxide concentrations ??? 1.25??mg L- 1 had no significant 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.

  1. Protective Effects of Minor Components of Curcuminoids on Hydrogen Peroxide-Treated Human HaCaT Keratinocytes.

    Liu, Yuh-Hwa; Lin, Yin-Shiou; Huang, Yu-Wei; Fang, Sheng-Uei; Lin, Shyr-Yi; Hou, Wen-Chi

    2016-05-11

    Hydrogen peroxide, one of the reactive oxygen species (ROS), can cause intracellular oxidative stress associated with skin aging and/or photoaging. Curcumin, a polyphenol in turmeric, has been reported to exhibit biological activity. In this study, five naturally occurring curcuminoids [curcumin, demethoxycurcumin (DMC), bisdemethoxycurcumin (BDMC), monohydroxy-DMC, and monohydroxy-BDMC] were used to investigate their protective roles against hydrogen peroxide-induced oxidative stress in the immortalized human keratinocyte cell lines (HaCaT cells). These five curcuminoids at 10 μM, but not at 5 μM, were shown to exhibit cytotoxicities toward HaCaT keratinocytes. Therefore, a 5 μM concentration of the five curcuminoids was selected for further investigations. Cells were pretreated with or without curcuminoids for 2.5 h before 24-h hydrogen peroxide (150 μM) treatments. Pretreatments with the minor components monohydroxy-DMC or monohydroxy-BDMC, but not curcumin, DMC, and BDMC, showed protective activity, elevating cell viability compared to cells with direct hydrogen peroxide treatments. Pretreatments with monohydroxy-DMC and monohydroxy-BDMC showed the best protective effects, reducing apoptotic cell populations and intracellular ROS, as demonstrated by flow cytometry, as well as reducing the changes of the mitochondrial membrane potential compared to cells with direct hydrogen peroxide treatments. The pretreatments with monohydroxy-DMC and monohydroxy-BDMC reduced c-jun and c-fos mRNA expression and p53 tumor suppressor protein expression and increased HO-1 protein expression and glutathione peroxidase (GPx) activity, respectively, compared to cells with direct hydrogen peroxide treatments. The five curcuminoids exhibited similar hydrogen peroxide-scavenging activity in vitro. It was proposed that monohydroxy-DMC and monohydroxy-BDMC could induce antioxidant defense systems better than curcumin, DMC, or BDMC could against hydrogen peroxide-induced oxidative

  2. Cytoskeletal changes as an early event in hydrogen peroxide-induced cell injury: a study in A549 cells.

    Raghu, G.; Striker, L.; Harlan, J; Gown, A.; Striker, G

    1986-01-01

    Hydrogen peroxide (H2O2) and other oxygen metabolites have been implicated in the pathogenesis of cell and tissue injury. The nature of the injury occurring in cells exposed to oxygen metabolites is unknown. A549 cells, derived from human lung carcinoma, were exposed to glucose-glucose oxidase or hydrogen peroxide in vitro. The distribution of actin and cytokeratin filaments, as well as 51chromium (51Cr) release and trypan blue dye exclusion were assessed. Both glucose-glucose oxidase and H2O...

  3. The effect of hydrogen peroxide on uranium oxide films on 316L stainless steel

    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

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

    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

  5. Hydrogen: Adding Value and Flexibility to the Nuclear Power Industry

    The objective of this study was to assess potential synergies between the hydrogen economy and nuclear energy options. Specifically: to provide a market analysis of advanced nuclear energy options for hydrogen production in growing hydrogen demand; to conduct an impact evaluation of nuclear-based hydrogen production on the economics of the energy system, environmental emissions, and energy supply security; and to identify competing technologies and challenges to nuclear options

  6. Azide protection of bacteroides superoxide dismutases from inactivation by hydrogen peroxide

    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 (NaN3) and are irreversibly inactivated upon incubation with hydrogen peroxide (H2O2). H2O2 inactivation of the enzyme likely depends on a Fenton type reaction with the production of hydroxyl radical (OH). Addition of NaN3 to the enzyme solution decreased the rate of inactivation by H2O2. After 20 minutes incubation of purified B. distasonis FeSOD with 2.5 mM H2O2, 61% of the initial enzymatic activity remained when 1 mM NaN3 was also present compared with 29% activity without NaN3. Similar results were seen with FeSOD from B. fragilis and B. thetaiotaomicron. Metal analyses of the native, peroxidized, and NaN3 protected samples are consistent with loss of Fe from the enzyme upon peroxidation, but retention of Fe and enzymatic activity in the NaN3 protected sample. Protection of FeSOD activity from H2O2 inactivation was dependent on NaN3 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 H2O2 or altering Fe redox potential, preventing OH production

  7. Electron paramagnetic resonance study of lipid and protein membrane components of erythrocytes oxidized with hydrogen peroxide

    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

  8. Electron paramagnetic resonance study of lipid and protein membrane components of erythrocytes oxidized with hydrogen peroxide

    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.

  9. Evaluation of vaporized hydrogen peroxide, Citrox and pH neutral Ecasol for decontamination of an enclosed area: a pilot study.

    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.

  10. Homolytic Cleavage of Both Heme-Bound Hydrogen Peroxide and Hydrogen Sulfide Leads to the Formation of Sulfheme.

    Arbelo-Lopez, Hector D; Simakov, Nikolay A; Smith, Jeremy C; Lopez-Garriga, Juan; Wymore, Troy

    2016-08-01

    Many heme-containing proteins with a histidine in the distal E7 (HisE7) position can form sulfheme in the presence of hydrogen sulfide (H2S) and a reactive oxygen species such as hydrogen peroxide. For reasons unknown, sulfheme derivatives are formed specifically on solvent-excluded heme pyrrole B. Sulfhemes severely decrease the oxygen-binding affinity in hemoglobin (Hb) and myoglobin (Mb). Here, use of hybrid quantum mechanical/molecular mechanical methods has permitted characterization of the entire process of sulfheme formation in the HisE7 mutant of hemoglobin I (HbI) from Lucina pectinata. This process includes a mechanism for H2S to enter the solvent-excluded active site through a hydrophobic channel to ultimately form a hydrogen bond with H2O2 bound to Fe(III). Proton transfer from H2O2 to His64 to form compound (Cpd) 0, followed by hydrogen transfer from H2S to the Fe(III)-H2O2 complex, results in homolytic cleavage of the O-O and S-H bonds to form a reactive thiyl radical (HS(•)), ferryl heme Cpd II, and a water molecule. Subsequently, the addition of HS(•) to Cpd II, followed by three proton transfer reactions, results in the formation of a three-membered ring ferric sulfheme that avoids migration of the radical to the protein matrix, in contrast to that in other peroxidative reactions. The transformation of this three-membered episulfide ring structure to the five-membered thiochlorin ring structure occurs through a significant potential energy barrier, although both structures are nearly isoenergetic. Both three- and five-membered ring structures reveal longer NB-Fe(III) bonds compared with other pyrrole nitrogen-Fe(III) bonds, which would lead to decreased oxygen binding. Overall, these results are in agreement with a wide range of experimental data and provide fertile ground for further investigations of sulfheme formation in other heme proteins and additional effects of H2S on cell signaling and reactivity. PMID:27357070

  11. Fluorescence signaling of Zr4+ by hydrogen peroxide assisted selective desulfurization of thioamide.

    Hwang, Jiyoung; Choi, Myung Gil; Eor, Suyoung; Chang, Suk-Kyu

    2012-02-01

    Thioamide derivative with a pyrene fluorophore was smoothly transformed to its corresponding amide by Zr(4+) ions in the presence of hydrogen peroxide. The transformation was evidenced by (1)H NMR spectroscopy and the signaling was completed within 10 min after sample preparation. Interference from Ag(+) and Hg(2+) ions in Zr(4+)-selective fluorescence signaling was readily suppressed with the use of Sn(2+) as a reducing additive. Discrimination of Zr(4+) from closely related hafnium, which is a frequent contaminant in commercial zirconium, was not possible. Prominent Zr(4+)-selective turn-on type fluorescence signaling was possible with a detection limit of 4.6 × 10(-6) M in an aqueous 99% ethanol solution. PMID:22260347

  12. ITO electrode modified by a gold ion implantation technique for direct electrocatalytic sensing of hydrogen peroxide

    We report on a simple strategy for the fabrication of gold nanoparticles (AuNPs) on an indium tin oxide substrate using a modified ion implantation method. The morphology, structure and electrochemical features of AuNPs were characterized by atomic force microscopy, electrochemical impedance spectroscopy and cyclic voltammetry. The modified electrode has a large electrochemically active surface and enables strong loading with cytochrome c (Cyt c) proteins. It undergoes enhanced electron transfer at uncompromised electrochemical activity, and also displays good stability and repeatability. The immobilized Cyt c exhibits good electrocatalytic activity towards hydrogen peroxide (H2O2), with a linear relationship between the catalytic current during differential pulse voltammetry and the concentration of H2O2 in the 0.05 μM to 0.2 μM range. The detection limit (S/N = 3) is 0. 01 μM. (author)

  13. Amperometric sensing of hydrogen peroxide using glassy carbon electrode modified with copper nanoparticles

    Sophia, J.; Muralidharan, G., E-mail: muraligru@gmail.com

    2015-10-15

    In this paper, fabrication of glassy carbon electrode (GCE) modified with nano copper particles is discussed. The modified electrode has been tested for the non-enzymatic electrochemical detection of hydrogen peroxide (H{sub 2}O{sub 2}). The copper nanoparticles (Cu NPs) were prepared employing a simple chemical reduction method. The presence of Cu NPs was confirmed through UV–visible (UV–vis) absorption spectroscopy and X-ray diffraction (XRD) analysis. The size and morphology of the particles were investigated using transmission electron microscopy (TEM). The electrochemical properties of the fabricated sensor were studied via cyclic voltammetry (CV), chronoamperometry and electrochemical impedance spectroscopy (EIS). The electrochemical sensor displayed excellent performance features towards H{sub 2}O{sub 2} detection exhibiting wide linear range, low detection limit, swift response time, good reproducibility and stability.

  14. Effects of UV radiation on the preparation of polypyrrole in the presence of hydrogen peroxide

    Zhang, Shihu; Lv, Guowei; Wang, Guolong; Zhu, Kaiming; Yu, Demei; Shao, Jinyou

    2015-10-01

    Conductive polypyrrole was synthesized with hydrogen peroxide (H2O2) as the oxidant. To promote the polymerization of pyrrole, UV radiation was employed. The effects of UV radiation on the preparation of polypyrrole were investigated. The polymerization of pyrrole was conducted with the H2O2 concentration in the range of 0.12-0.96 M and the H2SO4 concentration in the range of 6.8×10-4-0.19 M. The structure characterization indicated that the product polypyrrole was overoxidized partly depending on the concentrations of H2SO4 and H2O2. The increase in H2O2 concentration led to a slight increase in the oxidation and overoxidation of polypyrrole, simultaneously. However, the increase in H2SO4 concentration effectively suppressed the overoxidation of polypyrrole. The morphology, conductivity and thermal stability of the products were also characterized.

  15. A hydrogen peroxide electrochemical sensor based on silver nanoparticles decorated three-dimensional graphene

    A facile strategy has been developed to synthesize sliver nanoparticles (Ag NPs) decorated three-dimensional graphene (3DG) through hydrothermal process. The AgNPs-3DG composites are directly fabricated into a free standing sensing electrode for electrochemical detection of hydrogen peroxide (H2O2) in phosphate buffered solutions. Various techniques equipments including scanning electron microscopy, X-ray diffraction, and Raman spectroscopy are used to characterize the morphology and structure of the as-prepared composite. The electrochemical experiments reveal the AgNPs-3DG based biosensor exhibits fast amperometric sensing, low detection limitation, wide linear responding range, and perfect selectivity for non-enzyme H2O2 detection, indicating the well synergistic effect of Ag NPs high electrocatalytic activity and 3DG high conductivity and large surface area.

  16. Hydrogen peroxide biosensor based on DNA-Hb modified gold electrode

    A hydrogen peroxide (H2O2) biosensor based on DNA-hemoglobin (Hb) modified electrode is described in this paper. The sensor was designed by DNA and hemoglobin dropletting onto gold electrode surface layer by layer. The sensor based on the direct electron transfer of iron of hemoglobin showed a well electrocatalytic response to the reduction of the H2O2. This sensor offered an excellent electrochemical response for H2O2 concentration below micromole level with high sensitivity and selectivity and short response time. Experimental conditions influencing the biosensor performance such as, pH, potential were optimized and assessed. The levels of the RSD's (2O2 was observed from 10 to 120 μM with the detection limit of 0.4 μM (based on the S/N = 3)

  17. A passive apparatus for controlled-flux delivery of biocides: hydrogen peroxide as an example

    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......) 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...... membrane release rates of H2O2 (factor of between 5 and 50) than laboratory membrane exposure assays using barnacle larvae....

  18. A hydrogen peroxide electrochemical sensor based on silver nanoparticles decorated three-dimensional graphene

    Zhan, Beibei; Liu, Changbing; Shi, Huaxia; Li, Chen; Wang, Lianhui [Key Laboratory for Organic Electronics and Information Displays (KLOEID), Nanjing University of Posts and Telecommunications, Nanjing 210023 (China); Huang, Wei, E-mail: iamxcdong@njtech.edu.cn, E-mail: iamwhuang@njtech.edu.cn; Dong, Xiaochen, E-mail: iamxcdong@njtech.edu.cn, E-mail: iamwhuang@njtech.edu.cn [Key Laboratory for Organic Electronics and Information Displays (KLOEID), Nanjing University of Posts and Telecommunications, Nanjing 210023 (China); Jiangsu-Singapore Joint Research Center for Organic/Bio-Electronics and Information Displays and Institute of Advanced Materials (IAM), Nanjing Tech University, 30 South Puzhu Road, Nanjing 211816 (China)

    2014-06-16

    A facile strategy has been developed to synthesize sliver nanoparticles (Ag NPs) decorated three-dimensional graphene (3DG) through hydrothermal process. The AgNPs-3DG composites are directly fabricated into a free standing sensing electrode for electrochemical detection of hydrogen peroxide (H{sub 2}O{sub 2}) in phosphate buffered solutions. Various techniques equipments including scanning electron microscopy, X-ray diffraction, and Raman spectroscopy are used to characterize the morphology and structure of the as-prepared composite. The electrochemical experiments reveal the AgNPs-3DG based biosensor exhibits fast amperometric sensing, low detection limitation, wide linear responding range, and perfect selectivity for non-enzyme H{sub 2}O{sub 2} detection, indicating the well synergistic effect of Ag NPs high electrocatalytic activity and 3DG high conductivity and large surface area.

  19. Assessment of cell death studies by monitoring hydrogen peroxide in cell culture.

    Hirsch, Irina; Prell, Erik; Weiwad, Matthias

    2014-07-01

    Hydrogen peroxide (H2O2) has been widely used to study the oxidative stress response. However, H2O2 is unstable and easily decomposes into H2O and O2. Consequently, a wide range of exposure times and treatment concentrations has been described in the literature. In the present study, we established a ferrous oxidation-xylenol orange (FOX) assay, which was originally described for food and body liquids, as a method for the precise quantification of H2O2 concentrations in cell culture media. We observed that the presence of FCS and high cell densities significantly accelerate the decomposition of H2O2, therefore acting as a protection against cell death by accidental necrosis. PMID:24747006

  20. Amperometric sensing of hydrogen peroxide using glassy carbon electrode modified with copper nanoparticles

    In this paper, fabrication of glassy carbon electrode (GCE) modified with nano copper particles is discussed. The modified electrode has been tested for the non-enzymatic electrochemical detection of hydrogen peroxide (H2O2). The copper nanoparticles (Cu NPs) were prepared employing a simple chemical reduction method. The presence of Cu NPs was confirmed through UV–visible (UV–vis) absorption spectroscopy and X-ray diffraction (XRD) analysis. The size and morphology of the particles were investigated using transmission electron microscopy (TEM). The electrochemical properties of the fabricated sensor were studied via cyclic voltammetry (CV), chronoamperometry and electrochemical impedance spectroscopy (EIS). The electrochemical sensor displayed excellent performance features towards H2O2 detection exhibiting wide linear range, low detection limit, swift response time, good reproducibility and stability

  1. Hydrogen peroxide generation by the Weissberger biogenic oxidative system during hyaluronan degradation.

    Valachová, Katarina; Topoľská, Dominika; Mendichi, Raniero; Collins, Maurice N; Sasinková, Vlasta; Šoltés, Ladislav

    2016-09-01

    By applying the enzyme catalase, our study on hyaluronan degradation confirms the generation of hydrogen peroxide using the Weissberger biogenic oxidative system (WBOS), which is composed of ascorbate and cupric ions. Dynamic viscosities of hyaluronan (HA) solutions influenced by WBOS in the absence and presence of catalase were analysed by rotational viscometry. Molar masses of HAs were determined by size-exclusion chromatography with multi-angle laser-light scattering. Our results show that catalase dose-dependently inhibited the degradation of HA macromolecules, which presumably confirms the generation of H2O2 in the reaction system. This has implications in range of biomedical applications such as arthritic joint treatment, tissue engineering, ocular and cosmetic surgery. PMID:27185130

  2. The Hydroxyl Radical is a Critical Intermediate in the Voltammetric Detection of Hydrogen Peroxide.

    Roberts, James G; Voinov, Maxim A; Schmidt, Andreas C; Smirnova, Tatyana I; Sombers, Leslie A

    2016-03-01

    Cyclic voltammetry is a widely used and powerful tool for sensitively and selectively measuring hydrogen peroxide (H2O2). Herein, voltammetry was combined with electron paramagnetic resonance spectroscopy to identify and define the role of an oxygen-centered radical liberated during the oxidation of H2O2. The spin-trap reagents, 5,5-dimethyl-1-pyrroline N-oxide (DMPO) and 2-ethoxycarbonyl-2-methyl-3,4-dihydro-2H-pyrrole-1-oxide (EMPO), were employed. Spectra exhibit distinct hyperfine patterns that clearly identify the DMPO(•)-OH and EMPO(•)-OH adducts. Multiple linear regression analysis of voltammograms demonstrated that the hydroxyl radical is a principal contributor to the voltammetry of H2O2, as signal is attenuated when this species is trapped. These data incorporate a missing, fundamental element to our knowledge of the mechanisms that underlie H2O2 electrochemistry. PMID:26840154

  3. Chemical ionization tandem mass spectrometer for the in situ measurement of methyl hydrogen peroxide

    A new approach for measuring gas-phase methyl hydrogen peroxide [(MHP) CH3OOH] utilizing chemical ionization mass spectrometry is presented. Tandem mass spectrometry is used to avoid mass interferences that hindered previous attempts to measure atmospheric CH3OOH with CF3O- clustering chemistry. CH3OOH has been successfully measured in situ using this technique during both airborne and ground-based campaigns. The accuracy and precision for the MHP measurement are a function of water vapor mixing ratio. Typical precision at 500 pptv MHP and 100 ppmv H2O is ±80 pptv (2 sigma) for a 1 s integration period. The accuracy at 100 ppmv H2O is estimated to be better than ±40%. Chemical ionization tandem mass spectrometry shows considerable promise for the determination of in situ atmospheric trace gas mixing ratios where isobaric compounds or mass interferences impede accurate measurements.

  4. Surface characterization and chemical analysis of bamboo substrates pretreated by alkali hydrogen peroxide.

    Song, Xueping; Jiang, Yan; Rong, Xianjian; Wei, Wei; Wang, Shuangfei; Nie, Shuangxi

    2016-09-01

    The surface characterization and chemical analysis of bamboo substrates by alkali hydrogen peroxide pretreatment (AHPP) were investigated in this study. The results tended to manifest that AHPP prior to enzymatic and chemical treatment was potential for improving accessibility and reactivity of bamboo substrates. The inorganic components, organic solvent extractives and acid-soluble lignin were effectively removed by AHPP. X-ray photoelectron spectroscopy (XPS) analysis indicated that the surface of bamboo chips had less lignin but more carbohydrate after pre-treatment. Fiber surfaces became etched and collapsed, and more pores and debris on the substrate surface were observed with Scanning Electron Microscopy (SEM). Brenauer-Emmett-Teller (BET) results showed that both of pore volume and surface area were increased after AHPP. Although XRD analysis showed that AHPP led to relatively higher crystallinity, pre-extraction could overall enhance the accessibility of enzymes and chemicals into the bamboo structure. PMID:27311789

  5. Touchless Technologies for Decontamination in the Hospital: a Review of Hydrogen Peroxide and UV Devices.

    Doll, Michelle; Morgan, Daniel J; Anderson, Deverick; Bearman, Gonzalo

    2015-09-01

    Reduction of microbial contamination of the hospital environment is a challenge, yet has potential impacts on infection prevention efforts. Fumigation and UV light devices for environmental cleaning have expanded into the health care setting with the goal of decontamination of difficult to clean or overlooked surfaces. In an era of increased scrutiny of hospital-acquired infections, increasingly, health care centers are adopting these "touchless" cleaning techniques as adjuncts to traditional manual cleaning. The evidence for improved clinical outcomes is lacking; yet, the experience with these devices continues to accumulate in the literature. We review the recently published data related to the use of hydrogen peroxide and UV light-based decontamination systems for cleaning of hospital rooms. Touchless cleaning technologies may provide an incremental benefit to standard practices by limiting cross-transmission of pathogens via environmental surfaces, though evidence of prevention of infections remains limited. PMID:26252970

  6. Glutathione mediation of papain inactivation by hydrogen peroxide and hydroxyl radicals

    Glutathione reacts with papainCys25SOH, formed by the reaction of papain with hydrogen peroxide, to give papainCys25SSG. Subsequent reaction of this mixed disulfide with glutathione is slow (k -1 sec-1). However, at 300C it is readily cleaved by cysteine to form active papain, i.e., papainCys25SH. Glutathione resembles cysteine in protecting papain by the scavenging of .OH radicals, but, unlike cysteine, glutathione gave no evidence for the repair of enzyme radical lesions or for the conversion of papainCys25S. radicals to repairable derivatives. Its overall effectiveness for reducing the radiation inactivation of papain in aqueous solution is much less than that of cysteine

  7. A Possible Biogenic Origin for Hydrogen Peroxide on Mars: The Viking Results Reinterpreted

    Houtkooper, J M; 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 reinterpreted in the light of this hypothesis. Our conclusion is that the hitherto mysterious oxidant in the martian soil, which evolves oxygen when humidified, might be H2O2 of biological origin. This interpretation has consequences for site selection for future missions to search for life on Mars.

  8. ExoMol line lists XV: A new hot line list for hydrogen peroxide

    Al-Refaie, Ahmed F; Ovsyannikov, Roman I; Tennyson, Jonathan; Yurchenko, Sergei N

    2016-01-01

    A computed line list for hydrogen peroxide, H$_2{}^{16}$O$_2$, applicable to temperatures up to $T=1250$~K is presented. A semi-empirical high accuracy potential energy surface is constructed and used with an {\\it ab initio} dipole moment surface as input TROVE to compute 7.5 million rotational-vibrational states and around 20 billion transitions with associated Einstein-$A$ coefficients for rotational excitations up to $J=85$. The resulting APTY line list is complete for wavenumbers below 6~000 cm$^{-1}$ ($\\lambda < 1.67$~$\\mu$m) and temperatures up to 1250~K. Room-temperature spectra are compared with laboratory measurements and data currently available in the HITRAN database and literature. Our rms with line positions from the literature is 0.152 \\cm\\ and our absolute intensities agree better than 10\\%. The full line list is available from the CDS databas

  9. Low-dose hydrogen peroxide application in closed recirculating aquaculture systems

    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 for a...... for RAS 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...... period of 3 months. The organic and nitrogenous loadings of the systems differed fourfold between the two groups and were achieved by predefined constant daily feed loads and constant additions of water. The fixed cumulative feed burden was 1.6 × 103 mg feed/L in the low-intensity RAS and 6.3 × 103 mg...

  10. ExoMol line lists - XV. A new hot line list for hydrogen peroxide

    Al-Refaie, Ahmed F.; Polyansky, Oleg L.; Ovsyannikov, Roman I.; Tennyson, Jonathan; Yurchenko, Sergei N.

    2016-09-01

    A computed line list for hydrogen peroxide, H216O2, applicable to temperatures up to T = 1250 K is presented. A semi-empirical high-accuracy potential energy surface is constructed and used with an ab initio dipole moment surface as input TROVE to compute 7.5 million rotational-vibrational states and around 20 billion transitions with associated Einstein-A coefficients for rotational excitations up to J = 85. The resulting APTY line list is complete for wavenumbers below 6000 cm-1 (λ data currently available in the HITRAN data base and literature. Our rms with line positions from the literature is 0.152 cm-1 and our absolute intensities agree better than 10 per cent. The full line list is available from the CDS data base as well as at www.exomol.com.

  11. Highly sensitive detection of hydrogen peroxide at a carbon nanotube fiber microelectrode coated with palladium nanoparticles

    We report on a carbon nanotube (CNT) fiber microelectrode coated with palladium nanoparticles (PdNPs) and enabling electrochemical sensing of hydrogen peroxide (H2O2). The synergistic effects of the CNT fibers (good mechanical strength and large surface area) and of the PdNPs (high electrocatalytic activity) result in a microelectrode for H2O2 that exhibits a 2-s response time, a detection limit as low as 2 μM, a sensitivity of 2.75 A cm−2 M−1, and a linear response range from 2 μM to 1.3 mM (R = 0.9994). The sensor is also selective and not interfered by potentially competing species in biological fluids, thus representing an inexpensive but highly sensitive and selective microsensor for H2O2. (author)

  12. EDTA Chelation Therapy, Without Added Vitamin C, Decreases Oxidative DNA Damage and Lipid Peroxidation

    Chelation therapy is thought to not only remove contaminating metals, but also to decrease free radical production. However, in standard EDTA chelation therapy high doses of vitamin C with potential prooxidant effects are often added to the chelation solution. We demonstrated previously that the in...

  13. Electrochemical determination of hydrogen peroxide using -dianisidine as substrate and hemoglobin as catalyst

    Wei Sun; Hong Jiang; Kui Jiao

    2005-07-01

    A new electrochemical method for the determination of microamounts of hydrogen peroxide utilizing -dianisidine (ODA) as substrate and hemoglobin (Hb) as catalyst is described in this paper. Hb can be used as mimetic peroxidase and it can catalyse the reduction of hydrogen peroxide with the subsequent oxidation of ODA. The oxidative reaction product is an azo compound, which is an electroactive substance and has a sensitive second-order derivative polarographic reductive peak at the potential of -0.58 V (vs. SCE) in pH 8.0 Britton-Robinson (B-R) buffer solution. The conditions of Hb-catalytic reaction and polarographic detection of the reaction product were carefully studied. By using this polarographic peak and under optimal conditions, the calibration curve for the H2O2 was constructed in the linear range of 2.0 × 10-7 ∼ 1.0 × 10-4 mol/l with the detection limit of 5.0 × 10-8 mol/l. This method can also be used to the determination of Hb content in the range of 2.0 × 10-9 ∼ 3.0 × 10-7 mol/l with a detection limit of 1.0 × 10-9 mol/l. The proposed method was further applied to the determination of the content of H2O2 in fresh rainwater with satisfactory results. The catalytic reaction mechanism and the electrode reductive process of the reaction product were carefully studied.

  14. A luminescence-based probe for sensitive detection of hydrogen peroxide in seconds

    Highlights: • We describe a novel probe for the sensitive detection of H2O2. • H2O2 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 H2O2 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 (Tb3+) and phthalic acid (PA) in HEPES buffer is quenched in the presence of H2O2 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−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−1 to 2.56 mmol L−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 H2O2 in polluted river water samples. In conclusion, this fast and easy-to-use assay detects H2O2 with high sensitivity and precision

  15. A luminescence-based probe for sensitive detection of hydrogen peroxide in seconds

    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.

  16. Detection of hydrogen peroxide in Photosystem II (PSII using catalytic amperometric biosensor

    Ankush ePrasad

    2015-10-01

    Full Text Available Hydrogen peroxide (H2O2 is known to be generated in Photosystem II (PSII via enzymatic and non-enzymatic pathways. Hydrogen peroxide (H2O2 is known to be generated in Photosystem II (PSII via enzymatic and non-enzymatic pathways. Detection of H2O2 by different spectroscopic techniques has been explored, however its sensitive detection has always been a challenge in photosynthetic research. During the recent past, fluorescence probes such as Amplex Red has been used but is known to either lack specificity or limitation with respect to the minimum detection limit of H2O2. We have employed an electrochemical biosensor for real time monitoring of H2O2 generation at the level of sub-cellular organelles. The electrochemical biosensor comprises of counter electrode and working electrodes. The counter electrode is a platinum plate, while the working electrode is a mediator based catalytic amperometric biosensor device developed by the coating of a carbon electrode with osmium-horseradish peroxidase which acts as H2O2 detection sensor. In the current study, generation and kinetic behaviour of H2O2 in PSII membranes have been studied under light illumination. Electrochemical detection of H2O2 using the catalytic amperometric biosensor device is claimed to serve as a promising technique for detection of H2O2 in photosynthetic cells and subcellular structures including PSII or thylakoid membranes. It can also provide a precise information on qualitative determination of H2O2 and thus can be widely used in photosynthetic research.

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

    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

  18. Effect of biosubstances on the depleted uranium-hydrogen peroxide system

    Recently the chemical toxicity of depleted uranium is in the center of wide interest, because of its military use. Hamilton et al. reported the formation of reactive oxygen species (ROS) in the uranium-hydrogen peroxide system. Miller et al. reported the DNA damage by depleted uranium, suggesting a little affect of alpha-decay. The effort should be, therefore, concentrated on the study of ROS formation by DU under various conditions. In the present study, the characteristics and the mechanism of hydroxyl radical formation in the depleted uranium (DU)-hydrogen peroxide (H2O2) system and the effects of anti-oxidants on the system were studied. Hydroxyl radical were produced both in UO22+ - H2O2 and UO2+ - H2O2 systems. Kinetic study of these systems indicated that the hydroxyl radical formation in the UO22+ - H2O2 system could be described as a stepwise reaction process including the reduction of UO22+ to UO2+ by H2O2 and the Fenton-type reaction of UO2+ with H2O2. Glucose and glucosamine, acting as ordinal radical scavengers in the UV-irradiated H2O2 system, indicated quite different behaviors each other in the UO22+ - H2O2 system. Amino acids and peptides little bit depressed the hydroxyl radical formation both in the UV-irradiated H2O2 and the UO22+ - H2O2 systems. These results indicated that the behavior of biosubstances in the UO22+ - H2O2 system could be explained by the direct elimination of hydroxyl radical and the coupling of UO22+ ion with these compounds. Both effects are possible to raise the chemical toxicity of depleted uranium.

  19. Hydrogen peroxide induced cell death: One or two modes of action?

    Uhl, Lionel; Gerstel, Audrey; Chabalier, Maialène; Dukan, Sam

    2015-12-01

    Imlay and Linn show that exposure of logarithmically growing Escherichia coli to hydrogen peroxide (H2O2) leads to two kinetically distinguishable modes of cell killing. Mode one killing is pronounced near 1 mM concentration of H2O2 and is caused by DNA damage, whereas mode-two killing requires higher concentration ([Formula: see text]). The second mode seems to be essentially due to damage to all macromolecules. This phenomenon has also been observed in Fenton in vitro systems with DNA nicking caused by hydroxyl radical ([Formula: see text]). To our knowledge, there is currently no mathematical model for predicting mode one killing in vitro or in vivo after H2O2 exposure. We propose a simple model, using Escherichia coli as a model organism and a set of ordinary differential equations. Using this model, we show that available iron and cell density, two factors potentially involved in ROS dynamics, play a major role in the prediction of the experimental results obtained by our team and in previous studies. Indeed the presence of the mode one killing is strongly related to those two parameters. To our knowledge, mode-one death has not previously been explained. Imlay and Linn (Imlay and Linn, 1986) suggested that perhaps the amount of the toxic species was reduced at high concentrations of H2O2 because hydroxyl (or other) radicals might be quenched directly by hydrogen peroxide with the concomitant formation of superoxide anion (a less toxic species). We demonstrate (mathematically and numerically) that free available iron decrease is necessary to explain mode one killing which cannot appear without it and that H2O2 quenching or consumption is not responsible for mode-one death. We are able to follow ROS concentration (particularly responsible for mode one killing) after exposure to H2O2. This model therefore allows us to understand two major parameters involved in the presence or not of the first killing mode. PMID:27441232

  20. Sulfur mustard destruction using ozone, UV, hydrogen peroxide and their combination

    Numerous methods are used for destruction of sulfur mustard. Oxidation is one of those methods. There have been only limited data concerning application of the advanced oxidation technologies (AOTs) for mustard destruction available before. In this study sulfur mustard oxidation rate depending on kind of the oxidative system and process parameters used was assessed using selected AOT. The following were selected for mustard oxidation: ozone (O3), UV light (UV), hydrogen peroxide (H2O2); double systems: UV/O3, UV/H2O2, and O3/H2O2; a triple system: O3/H2O2/UV and Fenton reaction. Effectiveness of the selected AOT methods has been evaluated and the most suitable one for mustard destruction was chosen. Using ozone in various combinations with hydrogen peroxide and UV radiation mustard can be destroyed much quicker comparing to the classical oxidizers. Fast mustard oxidation (a few minutes) occurred in those systems where ozone alone was used, or in the following combinations: O3/H2O2, O3/UV and O3/H2O2/UV. When those advanced oxidation technologies are used, mustard becomes destroyed mainly in course of the direct oxidation with ozone, and reactions of mustard with radicals formed due to ozone action play a secondary role. Rate of sulfur mustard oxidation in the above mentioned ozone-containing oxidative systems decreases with pH value increasing from 2 to 12. Only when pH value of reaction solutions is close to pH 5, mustard oxidation rate is minimal, probably due to 'disappearance' of radicals participating in oxidation in this pH. Sulfur mustard can be most effectively destroyed using just ozone in pH 7. In that case mustard destruction rate is only slightly lower than the rate achieved in optimal conditions, and the system is the simplest

  1. Processing of LEU targets for 99Mo production - Dissolution of metal foil targets by alkaline hydrogen peroxide

    In FY 1995, we started studies on a new process for dissolution of low-enriched uranium (LEU) targets for 99Mo production. In this process, an LEU metal foil target is dissolved in a mixture of sodium hydroxide and hydrogen peroxide, then 99Mo is recovered from the dissolved solution. We focused on the dissolution kinetics to develop a mechanistic model for predicting the products and the rate of uranium dissolution under process conditions. We thoroughly studied the effects of hydrogen peroxide concentration, sodium hydroxide concentration, and temperature on the rate of uranium dissolution. It was found that uranium dissolution can be classified into a low-base (0.2M) process. In the low-base process, both the equilibrium hydrogen peroxide and hydroxide concentrations affect the rate of uranium dissolution; in the high base process, uranium dissolution is a 0.25th order reaction with respect to the equilibrium hydrogen peroxide. The dissolution activation energy was experimentally determined to be 48.8 kJ/mol. Generally, the rate of uranium dissolution increases to a maximum as the hydroxide concentration is increased from 0.01 to about 1.5M, then it decreases as the hydroxide concentration is further increased. The alkalinity of the dissolution solution is an important factor that affects not only the dissolution rate, but also the amount of radioactive waste. (author)

  2. Study using 18-oxygen, of the formation process of hydrogen peroxide during gamma irradiation of starch powder

    The isotopic content (18O) of hydrogen peroxide, formed during gamma irradiation of starch powder in presence of labelled or not labelled water and oxygen, is determined. The results lead to proof of a dismutation mechanism between peroxyl radicals (or superoxyl radicals)

  3. A SIFT Study of the Reactions of H3O+, NO+ and O2+ with Hydrogen Peroxide and Peroxyacetic Acid

    Španěl, Patrik; Diskin, A. M.; Wang, T.; Smith, D.

    2003-01-01

    Roč. 228, - (2003), s. 269-283. ISSN 1387-3806 R&D Projects: GA ČR GA202/03/0827; GA ČR GA203/02/0737 Institutional research plan: CEZ:AV0Z4040901 Keywords : SIFT * hydrogen peroxide * peroxyacetic acid Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.361, year: 2003

  4. Fluorimetric determination of hydrogen peroxide production by the haemocytes of the wax moth Galleria mellonella (Lepidoptera: Pyralidae)

    Vašíček, Ondřej; Papežíková, Ivana; Hyršl, P.

    2011-01-01

    Roč. 108, č. 3 (2011), s. 481-485. ISSN 1210-5759 Grant ostatní: GA ČR(CZ) GP206/09/P470 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : Galleria mellonella * fluorescence * hydrogen peroxide Subject RIV: BO - Biophysics Impact factor: 1.061, year: 2011

  5. Coordination Complexes as Catalysts: The Oxidation of Anthracene by Hydrogen Peroxide in the Presence of VO(acac)[subscript 2

    Charleton, Kimberly D. M.; Prokopchuk, Ernest M.

    2011-01-01

    A laboratory experiment aimed at students who are studying coordination chemistry of transition-metal complexes is described. A simple vanadyl acetylacetonate complex can be used as a catalyst in the hydrogen peroxide oxidation of anthracene to produce anthraquinone. The reaction can be performed under a variety of reaction conditions, ideally by…

  6. FLUX DETERMINATION AND PHYSIOLOGICAL RESPONSE IN THE EXPOSURE OF RED SPRUCE TO GASEOUS HYDROGEN PEROXIDE, OZONE, AND SULFUR DIOXIDE

    We report on the 3-week exposure of a branch of a forest-grown red spruce (Picea rubens) sapling to the combination of gaseous hydrogen peroxide. ozone, and sulfur dioxide. he exposure was conducted continuously using concentrations of H2O2, O3, and SO2 that have been observed du...

  7. Auxin increases the hydrogen peroxide (H2O2) concentration in tomato (Solanum lycopersicum) root tips while inhibiting root growth

    Ivanchenko, M. G.; den Os, D.; Monshausen, G. B.; Dubrovsky, J, G.; Bednářová, Andrea; Krishnan, N.

    2013-01-01

    Roč. 112, č. 6 (2013), s. 1107-1116. ISSN 0305-7364 R&D Projects: GA ČR GAP501/10/1215 Grant ostatní: GA JU(CZ) 062/2011/P Institutional support: RVO:60077344 Keywords : auxin * ROS * hydrogen peroxide Subject RIV: EF - Botanics Impact factor: 3.295, year: 2013

  8. White tea (Camellia sinensis Kuntze) exerts neuroprotection against hydrogen peroxide-induced toxicity in PC12 cells.

    López, Víctor; Calvo, Maria Isabel

    2011-03-01

    Tea is a popular beverage whose consumption is associated with prevention of certain disorders. The objective of the study was to investigate the potential neuroprotective effect of white tea extract (WTE) on hydrogen peroxide induced toxicity in PC12 cells. Cells were treated with various doses of WTE (10-250 μg/ml) before exposition to 250 μM hydrogen peroxide and cell survival was determined through the MTT and LDH assays. Oxidative stress was quantified in the cells after treatments as intracellular reactive oxygen species (ROS) production and the antioxidant activity of the extract was assessed in a cell free system in terms of free radical scavenging capacity. Results showed that WTE has a significant protective effect in the PC12 cell line against hydrogen peroxide as cell survival was significantly superior in WTE-treated cells compared to hydrogen peroxide-treated cells. A reduction on intracellular oxidative stress as well as radical scavenging properties were produced by WTE. Results suggest that WTE protects PC12 cells against H(2)O(2)-induced toxicity, and that an antioxidant mechanism through ROS scavenging may be in part responsible for cells neuroprotection. PMID:21271291

  9. Effect of hydrogen peroxide and/or Flavobacterium psychrophilum on the gills of rainbow trout, Oncorhynchus mykiss (Walbaum)

    Henriksen, Maya Maria Mihályi; Kania, P. W.; Buchmann, K.; Dalsgaard, Inger

    2015-01-01

    The immune response and morphological changes in the gills of rainbow trout fry after immersion in hydrogen peroxide (H2O2), Flavobacterium psychrophilum or combined exposure were examined. The gills were sampled 4, 48, 125 and 192 h after exposure, and the regulation of expression of the followi...

  10. Field-controlled electron transfer and reaction kinetics of the biological catalytic system of microperoxidase-11 and hydrogen peroxide

    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.

  11. Kinetic spectrophotometric determination of Bi(III based on its catalytic effect on the oxidation of phenylfluorone by hydrogen peroxide

    SOFIJA M. RANČIĆ

    2009-08-01

    Full Text Available A new reaction was suggested and a new kinetic method was elaborated for determination of Bi(III in solution, based on its catalytic effect on the oxidation of phenyl-fluorone (PF by hydrogen peroxide in ammonia buffer. By application of spectrophotometric technique, a limit of quantification (LQ of 128 ng cm-3 was reached, and the limit of detection (LD of 37 ng cm-3 was obtained, where LQ was defined as the ratio signal:noise = 10:1 and LD was defined as signal 3:1 against the blank. The RSD value was found to be in the range 2.8–4.8 % for the investigated concentration range of Bi(III. The influence of some ions upon the reaction rate was tested. The method was confirmed by determining Bi(III in a stomach ulcer drug (“Bicit HP”, Hemofarm A.D.. The obtained results were compared to those obtained by AAS and good agreement of results was obtained.

  12. Greener Selective Cycloalkane Oxidations with Hydrogen Peroxide Catalyzed by Copper-5-(4-pyridyltetrazolate Metal-Organic Frameworks

    Luísa Martins

    2015-10-01

    Full Text Available Microwave assisted synthesis of the Cu(I compound [Cu(µ4-4-ptz]n [1, 4-ptz = 5-(4-pyridyltetrazolate] has been performed by employing a relatively easy method and within a shorter period of time compared to its sister compounds. The syntheses of the Cu(II compounds [Cu3(µ3-4-ptz4(µ2-N32(DMF2]n∙(DMF2n (2 and [Cu(µ2-4-ptz2(H2O2]n (3 using a similar method were reported previously by us. MOFs 1-3 revealed high catalytic activity toward oxidation of cyclic alkanes (cyclopentane, -hexane and -octane with aqueous hydrogen peroxide, under very mild conditions (at room temperature, without any added solvent or additive. The most efficient system (2/H2O2 showed, for the oxidation of cyclohexane, a turnover number (TON of 396 (TOF of 40 h−1, with an overall product yield (cyclohexanol and cyclohexanone of 40% relative to the substrate. Moreover, the heterogeneous catalytic systems 1–3 allowed an easy catalyst recovery and reuse, at least for four consecutive cycles, maintaining ca. 90% of the initial high activity and concomitant high selectivity.

  13. Precipitation of uranium by hydrogen peroxide from the liquor of Xiamatang uranium ore

    A Chemical precipitation process of recovering uranium from the leaching liquor of uranium ore was investigated. The process includes primarily precipitation of iron with lime, preprocessing of the slurry of iron hydroxide and precipitation of uranium with H2O2. The leaching liquor is neutralized by lime milk to pH 3.7 for precipitating iron hydroxide. The precipitated slurry is recycled to leaching process for recovering uranium in it after being flocculated and pre-processed. It can avoid the filter of the slurry of iron bydroxide. H2O2 is used to precipitate uranium in the leaching liquor free of iron, and the pH of process for uranium precipitation is adjusted to 3.5 by adding MgO slurry. It is shown in the results that lime, H2O2 and MgO can be used to obtain the uranium peroxide product containing over 65% uranium without environmental pollution

  14. An amperometric hydrogen peroxide biosensor based on Co3O4 nanoparticles and multiwalled carbon nanotube modified glassy carbon electrode

    Highlights: • Hydrogen peroxide biosensor was constructed by combining the advantageous properties of MWCNTs and Co3O4. • Incorporating Co3O4 nanoparticles into MWCNTs/gelatin film increased the electron transfer. • Co3O4/MWCNTs/gelatin/HRP/Nafion/GCE showed strong anti-interference ability. • Hydrogen peroxide was successfully determined in disinfector with an average recovery of 100.78 ± 0.89. - Abstract: In this work a new type of hydrogen peroxide biosensor was fabricated based on the immobilization of horseradish peroxidase (HRP) by cross-linking on a glassy carbon electrode (GCE) modified with Co3O4 nanoparticles, multiwall carbon nanotubes (MWCNTs) and gelatin. The introduction of MWCNTs and Co3O4 nanoparticles not only enhanced the surface area of the modified electrode for enzyme immobilization but also facilitated the electron transfer rate, resulting in a high sensitivity of the biosensor. The fabrication process of the sensing surface was characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Amperometric detection of hydrogen peroxide was investigated by holding the modified electrode at −0.30 V (vs. Ag/AgCl). The biosensor showed optimum response within 5 s at pH 7.0. The optimized biosensor showed linear response range of 7.4 × 10−7–1.9 × 10−5 M with a detection limit of 7.4 × 10−7. The applicability of the purposed biosensor was tested by detecting hydrogen peroxide in disinfector samples. The average recovery was calculated as 100.78 ± 0.89

  15. Seawater usable for production and consumption of hydrogen peroxide as a solar fuel

    Mase, Kentaro; Yoneda, Masaki; Yamada, Yusuke; Fukuzumi, Shunichi

    2016-05-01

    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.

  16. Hydrogen peroxide decomposition on a two-component CuO-Cr2O3 catalyst

    Some physical and catalytic properties of the two-component copper(II)oxide-chromium(III)oxide catalysts with different content of both components were studied using the decomposition of the aqueous solution of hydrogen peroxide as a test reaction. It was found that along to both basic components, the system under study also contained the spinel structure CuCr2O4, chromate washable by water and hexavalent ions of chromium unwashable by water. The soluble chromate was catalytically active. During the first period of the reaction the equilibrium was being established in both homogeneous and heterogeneous catalytic systems. The catalytic activity as well as the specific surface area of the washed solid is a non-monotonous function of its composition. It seems highly probable that the extreme values of both these quantities are not connected with the detected admixtures in the catalytic system. The system under study is very insensitive with regard to the applied doses of gamma radiation. Its catalytic properties change rather significantly after thermal treatment and particularly after the partial reduction to low degree by hydrogen. The observed changes of the catalytic activity of the system under study are very probably connected with the changes in the valence state of the catalytically active components of the catalyst. (author). 5 figs., 4 tabs., 16 refs

  17. Seawater usable for production and consumption of hydrogen peroxide as a solar fuel

    Mase, Kentaro; Yoneda, Masaki; Yamada, Yusuke; Fukuzumi, Shunichi

    2016-01-01

    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. PMID:27142725

  18. Seawater usable for production and consumption of hydrogen peroxide as a solar fuel.

    Mase, Kentaro; Yoneda, Masaki; Yamada, Yusuke; Fukuzumi, Shunichi

    2016-01-01

    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. PMID:27142725

  19. Dissection of the binding of hydrogen peroxide to trypsin using spectroscopic methods and molecular modeling

    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.

  20. Amperometric hydrogen peroxide and glucose biosensor based on NiFe2/ordered mesoporous carbon nanocomposites.

    Xiang, Dong; Yin, Longwei; Ma, Jingyun; Guo, Enyan; Li, Qun; Li, Zhaoqiang; Liu, Kegao

    2015-01-21

    Nanocomposites of NiFex embedded in ordered mesoporous carbon (OMC) (x = 0, 1, 2) were prepared by a wet impregnation and hydrogen reduction process and were used to construct electrochemical biosensors for the amperometric detection of hydrogen peroxide (H2O2) or glucose. The NiFe2/OMC nanocomposites were demonstrated to have a large surface area, suitable mesoporous channels, many edge-plane-like defective sites, and a good distribution of alloyed nanoparticles. The NiFe2/OMC and Nafion modified glass carbon electrode (GCE) exhibited excellent electrocatalytic activities toward the reduction of H2O2 as well. By utilizing it as a bioplatform, GOx (glucose oxidase) cross-linked with Nafion was immobilized on the surface of the electrode for the construction of an amperometric glucose biosensor. Our results indicated that the amperometric hydrogen peroxide biosensor (NiFe2/OMC + Nafion + GCE) showed good analytical performances in term of a high sensitivity of 4.29 μA mM(-1) cm(-2), wide linearity from 6.2 to 42,710 μM and a low detection limit of 0.24 μM at a signal-to-noise ratio of 3 (S/N = 3). This biosensor exhibited excellent selectivity, high stability and negligible interference for the detection of H2O2. In addition, the immobilized enzyme on NiFe2/OMC + Nafion + GCE, retaining its bioactivity, exhibited a reversible two-proton and two-electron transfer reaction, a fast heterogeneous electron transfer rate and an effective Michaelis-Menten constant (K) (3.18 mM). The GOx + NiFe2/OMC + Nafion + GCE could be used to detect glucose based on the oxidation of glucose catalyzed by GOx and exhibited a wide detection range of 48.6-12,500 μM with a high sensitivity of 6.9 μA mM(-1) cm(-2) and a low detection limit of 2.7 μM (S/N = 3). The enzymic biosensor maintained a high selectivity and stability features, and shows great promise for application in the detection of glucose. PMID:25429370

  1. Processing of LEU targets for 99Mo production - Dissolution of U3Si2 targets by alkaline hydrogen peroxide

    Low-enriched uranium silicide targets designed to recover fission product 99Mo were dissolved in alkaline hydrogen peroxide (H2O2 plus NaOH) at about 90 deg. C. Sintering of matrix aluminium powder during irradiation and heat treatment retarded aluminum dissolution and prevented silicide particle dispersion. Gas evolved during dissolution is suspected to adhere to particles and block hydroxide ion contact with aluminum. Reduction of base concentrations from 5M to 0.1M NaOH yielded similar silicide dissolution and peroxide destruction rates, simplifying later processing. Future work in particle dispersion enhancement, 99Mo separation, and waste disposal is also discussed. (author)

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

    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.

  3. Effects of Adding Sodium Nitroprusside to Semen Diluents on Motility, Viability and Lipid Peroxidation of Sperm in Holstein Bulls

    Khodaei, Hamidreza; Chamani, Mohammad; Mahdavi, Behnaz; Akhondi, Ali Asghar

    2016-01-01

    Background Nitric oxide (NO) that plays important role in all sexual activities of animals is made from the amino acid L-arginine by the enzymatic action of NO synthase (NOS). NO makes a band with sulfur-iron complexes, but due to production of steroid sexual hormones related to the enzymes involved in this complex, NO can change the activity of these enzymes. NO affects many cells including vein endothelial cells, macrophages and mast cells. These cells are also found in Leydig cells; therefore, they are important source of NO in testis tissue. Therefore, minimizing damages to sperm at the time of freezing thawing process are really important. The aim of this study was to determine the appropriate NO concentration to be added to the freezing extender to improve the quality of thawed sperm. Materials and Methods In this experimental randomized study, sperms of four Holstein bulls with an average age of 4 were collected twice a week for 3 weeks. They received sodium nitroprusside (SNP) in concentrations of 0, 10, 50 and 100 nmol/ml. Data analysis was performed using the special issue and static (SAS) 98 software. Also, mean comparison was done using Duncan’s multiple ranges test (P<0.05).This research was conducted at the laboratory of Science and Research Branch, Islamic Azad University, Tehran at spring and summer of 2013. Results All concentrations of SNP used was found to increase motility and viability of spermatozoa at 1, 2 and 3 hours after thawing, significantly (P<0.05), but there was no significant difference at zero time. Different concentrations of SNP reduced the membrane lipid peroxidation level of sperm and increased acrosome membranes integrity, implying that SNP generally improved samples membranes, especially in 50 and 100 nmol/ml concentrations. Conclusion According to the obtained results, addition of SNP to semen diluents increases motility and viability of spermatozoa. Also, it reduces membrane lipid peroxidation level that leads to improved

  4. Measurement of atmospheric hydrogen peroxide and organic peroxides in Beijing before and during the 2008 Olympic Games: Chemical and physical factors influencing their concentrations

    He, S. Z.; Chen, Z. M.; Zhang, X.; Zhao, Y.; Huang, D. M.; Zhao, J. N.; Zhu, T.; Hu, M.; Zeng, L. M.

    2010-09-01

    For the 2008 Beijing Olympic Games full-scale control (FSC) of atmospheric pollution was implemented to improve the air quality from 20 July to 20 September 2008, resulting in a significant decrease in the emission of pollutants in urban Beijing, especially vehicular emissions. The combination of reduced emissions and weather condition changes provided us with a unique opportunity to investigate urban atmospheric chemistry. Hydrogen peroxide (H2O2) and organic peroxides play significant roles in atmospheric processes, such as the cycling of HOx radicals and the formation of secondary sulfate aerosols and secondary organic aerosols. We measured atmospheric H2O2 and organic peroxides in urban Beijing, at the Peking University campus, from 12 July to 30 September, before and during the FSC. The major peroxides observed were H2O2, methyl hydroperoxide (MHP), and peroxyacetic acid (PAA), having maximal mixing ratios of 2.34, 0.95, and 0.17 ppbv (parts per billion by volume), respectively. Other organic peroxides were detected occasionally, such as bis-hydroxymethyl hydroperoxide, hydroxymethyl hydroperoxide, ethyl hydroperoxide, and 1-hydroxyethyl hydroperoxide. On sunny days the concentrations of H2O2, MHP, and PAA exhibited pronounced diurnal variations, with a peak in the afternoon (1500-1900) and, occasionally, a second peak in the evening (2000-0200). The night peaks can be attributed to local night production from the ozonolysis of alkenes, coupled with the reaction between NO3 radicals and organic compounds. Sunny-day weather dominated during 16-26 July, and we found that the concentrations of H2O2, MHP, and PAA increased strikingly on 22-26 July, compared with the concentrations during 16-19 July. This effect was mainly attributed to the NOx (NO and NO2) decline because of the FSC, due to (i) the suppressing effect of NO and NO2 on the production of peroxides and (ii) the indirect effect of reduced NOx on the concentration of peroxides via O3 production in the

  5. Sulfur mustard destruction using ozone, UV, hydrogen peroxide and their combination

    Popiel, Stanislaw [Institute of Chemistry, Military University of Technology, 2, Kaliskiego-Street, 00-908 Warsaw (Poland)], E-mail: spopiel@wat.edu.pl; Witkiewicz, Zygfryd [Institute of Chemistry, Military University of Technology, 2, Kaliskiego-Street, 00-908 Warsaw (Poland); ' Jan Kochanowski' Swietokrzyska Academy, Institute of Chemistry, 5, Checinska-Street, 25-020 Kielce (Poland); Chrzanowski, Michal [Institute of Chemistry, Military University of Technology, 2, Kaliskiego-Street, 00-908 Warsaw (Poland)

    2008-05-01

    Numerous methods are used for destruction of sulfur mustard. Oxidation is one of those methods. There have been only limited data concerning application of the advanced oxidation technologies (AOTs) for mustard destruction available before. In this study sulfur mustard oxidation rate depending on kind of the oxidative system and process parameters used was assessed using selected AOT. The following were selected for mustard oxidation: ozone (O{sub 3}), UV light (UV), hydrogen peroxide (H{sub 2}O{sub 2}); double systems: UV/O{sub 3}, UV/H{sub 2}O{sub 2}, and O{sub 3}/H{sub 2}O{sub 2}; a triple system: O{sub 3}/H{sub 2}O{sub 2}/UV and Fenton reaction. Effectiveness of the selected AOT methods has been evaluated and the most suitable one for mustard destruction was chosen. Using ozone in various combinations with hydrogen peroxide and UV radiation mustard can be destroyed much quicker comparing to the classical oxidizers. Fast mustard oxidation (a few minutes) occurred in those systems where ozone alone was used, or in the following combinations: O{sub 3}/H{sub 2}O{sub 2}, O{sub 3}/UV and O{sub 3}/H{sub 2}O{sub 2}/UV. When those advanced oxidation technologies are used, mustard becomes destroyed mainly in course of the direct oxidation with ozone, and reactions of mustard with radicals formed due to ozone action play a secondary role. Rate of sulfur mustard oxidation in the above mentioned ozone-containing oxidative systems decreases with pH value increasing from 2 to 12. Only when pH value of reaction solutions is close to pH 5, mustard oxidation rate is minimal, probably due to 'disappearance' of radicals participating in oxidation in this pH. Sulfur mustard can be most effectively destroyed using just ozone in pH 7. In that case mustard destruction rate is only slightly lower than the rate achieved in optimal conditions, and the system is the simplest.

  6. Structural characterization of alkaline hydrogen peroxide pretreated grasses exhibiting diverse lignin phenotypes

    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

  7. Modulation of Na+/K+ ATPase Activity by Hydrogen Peroxide Generated through Heme in L. amazonensis.

    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.

  8. Modulation of Na+/K+ ATPase Activity by Hydrogen Peroxide Generated through Heme in L. amazonensis.

    Rocco-Machado, Nathália; Cosentino-Gomes, Daniela; Meyer-Fernandes, José Roberto

    2015-01-01

    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. PMID:26070143

  9. Direct electron transfer biosensor for hydrogen peroxide carrying nanocomplex composed of horseradish peroxidase and Au-nanoparticle – Characterization and application to bienzyme systems

    Yusuke Okawa

    2015-09-01

    Full Text Available A reagentless electrochemical biosensor for hydrogen peroxide was fabricated. The sensor carries a monolayer of nanocomplex composed of horseradish peroxidase and Au-nanoparticle, and responds to hydrogen peroxide through the highly efficient direct electron transfer at a mild electrode potential without any soluble mediator. Formation of the nanocomplex was studied with visible spectroscopy and size exclusion chromatography. The sensor performance was analyzed based on a hydrodynamic electrochemical technique and enzyme kinetics. The sensor was applied to fabrication of sensors for glucose and uric acid through further modification of the nanocomplex-carrying electrode with the corresponding hydrogen peroxide-generating oxidases, glucose oxidase and urate oxidase, respectively.

  10. A Quest for the Origin of Barrier to the Internal Rotation ofHydrogen Peroxide (H2O2 and Fluorine Peroxide (F2O2

    Dulal C. Ghosh

    2006-08-01

    Full Text Available In order to understand the structure-property relationship, SPR, an energy-partitioning quest for the origin of the barrier to the internal rotation of two iso-structuralmolecules, hydrogen peroxide, H2O2, and fluorine peroxide, F2O2 is performed. Thehydrogen peroxide is an important bio-oxidative compound generated in the body cells tofight infections and is an essential ingredient of our immune system. The fluorine peroxideis its analogue. We have tried to discern the interactions and energetic effects that entail thenonplanar skew conformation as the equilibrium shape of the molecules. The physicalprocess of the dynamics of internal rotation initiates the isomerization reaction and generatesinfinite number of conformations. The decomposed energy components faithfully display thephysical process of skewing and eclipsing as a function of torsional angles and hence aregood descriptors of the process of isomerization reaction of hydrogen peroxide (H2O2 anddioxygen difluoride (F2O2 associated with the dynamics of internal rotation. It is observedthat the one-center, two-center bonded and nonbonded interaction terms are sharply dividedin two groups. One group of interactions hinders the skewing and favours planar cis/transforms while the other group favours skewing and prefers the gauche conformation of themolecule. The principal energetic effect forcing the molecules into the nonplanar gaucheform is the variation “O–O’ bond energy with torsion in both the molecules. It isdemonstrated that the barrier is not a regional effect rather it is made by the conjoint actionof all one- and two-center bonding and nonbonding interactions comprising the entireframework of the molecule. The present study claims to reveal one amazing feature of non-bonded interactions. Computed results of nonbonding interactions demonstrate that thenature of interaction between two formally positively charged non-bonding H atoms (H

  11. Involvement of intracellular free Ca2+ in enhanced release of herpes simplex virus by hydrogen peroxide

    Ogawa Yuzo

    2006-08-01

    Full Text Available Abstract Background It was reported that elevation of the intracellular concentration of free Ca2+ ([Ca2+]i by a calcium ionophore increased the release of herpes simplex virus type 1 (HSV-1. Freely diffusible hydrogen peroxide (H2O2 is implied to alter Ca2+ homeostasis, which further enhances abnormal cellular activity, causing changes in signal transduction, and cellular dysfunction. Whether H2O2 could affect [Ca2+]i in HSV-1-infected cells had not been investigated. Results H2O2 treatment increased the amount of cell-free virus and decreased the proportion of viable cells. After the treatment, an elevation in [Ca2+]i was observed and the increase in [Ca2+]i was suppressed when intracellular and cytosolic Ca2+ were buffered by Ca2+ chelators. In the presence of Ca2+ chelators, H2O2-mediated increases of cell-free virus and cell death were also diminished. Electron microscopic analysis revealed enlarged cell junctions and a focal disintegration of the plasma membrane in H2O2-treated cells. Conclusion These results indicate that H2O2 can elevate [Ca2+]i and induces non-apoptotic cell death with membrane lesions, which is responsible for the increased release of HSV-1 from epithelial cells.

  12. Hydrogen peroxide generation and photocatalytic degradation of estrone by microstructural controlled ZnO nanorod arrays

    Highlights: ► H2O2 generated by ZnO nanorod arrays during UV irradiation was detected. ► ZnO nanorod arrays were synthesized via a facile hydrothermal technique. ► The microstructure can be controlled by varying reactants’ concentration. ► Photocatalytic degradation of estrone by ZnO nanorod arrays was studied. ► Microstructures’ effect on photocatalysis and H2O2 generation was discussed. - Abstract: The strong oxidant, hydrogen peroxide (H2O2), generated by ZnO nanorod arrays under UV light irradiation was monitored by fluorescence analysis. The ZnO nanorod arrays were synthesized via a low temperature hydrothermal method and their dimensions, i.e., diameter and height, can be controlled by adjusting the concentration of zinc nitrate (Zn(NO3)2·6H2O) and hexamethylenetetramine (HMT). The morphology, nanostructure, surface roughness and optical property were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic force microscopy (AFM) and transmittance spectra, respectively. The ZnO nanorod arrays were applied in the degradation of estrone, which is an emerging steroid estrogen contaminant. The results revealed that the ZnO nanorod array produced from 25 mM Zn2+ and HMT had the highest aspect ratio, the largest surface roughness and the lowest band gap energy, which was beneficial to the efficiency of UV light utilization, photocatalytic degradation of estrone and H2O2 generation.

  13. Hydrogen peroxide contributes to the epithelial cell death induced by the oral mitis group of streptococci.

    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.

  14. Melanin bleaching with dilute hydrogen peroxide: a simple and rapid method.

    Liu, Chia-Hsing; Lin, Chih-Hung; Tsai, Min-Jan; Chen, Wan-Tzu; Chai, Chee-Yin; Huang, Ya-Chun; Tsai, Kun-Bow

    2013-05-01

    Melanins are naturally occurring pigments in both normal and pathologic tissues. Two common bleaching processes are potassium permanganate followed by oxalic acid treatment and dilute hydrogen peroxide (H2O2) process. The potassium permanganate/oxalic acid method is faster and more easily incorporated in conventional daily immunostaining protocols, whereas the dilute H2O2 method requires 24 hours. This study aimed to reduce melanin bleaching time by using a 10% H2O2 dilution. First, reaction time was reduced to 30 minutes by raising the temperature to 65°C. Second, containers with high thermal conductivity were used to improve bleaching effectiveness. Experimental comparisons of melanin treatments with H2O2 contained in an iron jar, a glass coplin jar, and a plastic steel jar obtained bleaching time of 20, 30, and 40 minutes, respectively. These modifications of the conventional bleaching method significantly improve the speed and efficiency of the procedure and are recommended when performing immunohistochemical studies. PMID:23060296

  15. Production of interstellar hydrogen peroxide (H2O2) on the surface of dust grains

    Du, Fujun; Bergman, Per

    2011-01-01

    Context. The formation of water on the dust grains in the interstellar medium may proceed with hydrogen peroxide (H2O2) as an intermediate. Recently gas-phase H2O2 has been detected in {\\rho} Oph A with an abundance of ~1E-10 relative to H2. Aims. We aim to reproduce the observed abundance of H2O2 and other species detected in {\\rho} Oph A quantitatively. Methods. We make use of a chemical network which includes gas phase reactions as well as processes on the grains; desorption from the grain surface through chemical reaction is also included. We run the model for a range of physical parameters. Results. The abundance of H2O2 can be best reproduced at ~6E5 yr, which is close to the dynamical age of {\\rho} Oph A. The abundances of other species such as H2CO, CH3OH, and O2 can be reasonably reproduced also at this time. In the early time the gas-phase abundance of H2O2 can be much higher than the current detected value. We predict a gas phase abundance of O2H at the same order of magnitude as H2O2, and an abund...

  16. Sunscreens as a source of hydrogen peroxide production in coastal waters.

    Sánchez-Quiles, David; Tovar-Sánchez, Antonio

    2014-08-19

    Sunscreens have been shown to give the most effective protection for human skin from ultraviolet (UV) radiation. Chemicals from sunscreens (i.e., UV filters) accumulate in the sea and have toxic effects on marine organisms. In this report, we demonstrate that photoexcitation of inorganic UV filters (i.e., TiO2 and ZnO nanoparticles) under solar radiation produces significant amounts of hydrogen peroxide (H2O2), a strong oxidizing agent that generates high levels of stress on marine phytoplankton. Our results indicate that the inorganic oxide nanoparticle content in 1 g of commercial sunscreen produces rates of H2O2 in seawater of up to 463 nM/h, directly affecting the growth of phytoplankton. Conservative estimates for a Mediterranean beach reveal that tourism activities during a summer day may release on the order of 4 kg of TiO2 nanoparticles to the water and produce an increment in the concentration of H2O2 of 270 nM/day. Our results, together with the data provided by tourism records in the Mediterranean, point to TiO2 nanoparticles as the major oxidizing agent entering coastal waters, with direct ecological consequences on the ecosystem. PMID:25069004

  17. Efficient and rapid microwave-assisted route to synthesize Pt–MnOx hydrogen peroxide sensor

    Highlights: • Carbon supported Pt-MnOx catalyst could be synthesized succesfully by microwave irradiation method. • Carbon supported Pt-MnOx non-enzymatic H2O2 sensor exhibits excellent selectivity, stability, and reproducibility • Carbon supported Pt-MnOx sensor can effectively resist the effect of interferents such as uric acid and ascorbic acid. - Abstract: A novel electrochemical sensor for the detection of hydrogen peroxide (H2O2) is proposed based on carbon supported Pt-MnOx and Pt nanoparticles, successfully synthesized via microwave irradiation polyol method. The physicochemical properties of the Pt-MnOx and Pt nanoparticles were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Transmission electron microscopy (TEM). Electrochemical properties of the nanoparticles were investigated by cyclic voltammetry (CV) and chronoamperometry (CA). Electrochemical measurements indicate that the oxidation current of H2O2 is linear (R2=0.998) to its concentration from 2 μM to 4.0 mM with a detection limit of 0.7 μM (signal/noise = 3). In addition, Pt-MnOx is not affected by ascorbic acid (AA) and uric acid (UA) which are common interfering species. Meanwhile, this Pt-MnOx non-enzymatic H2O2 sensor exhibits excellent selectivity, stability and reproducibility. Thus, this novel non-enzymatic sensor can be found practical applications in H2O2 detection

  18. A new enzymatic immobilization carrier based on graphene capsule for hydrogen peroxide biosensors

    Enzymatic loss and inactivation are two main problems which can affect the performance of the biosensor. In order to resolve these two problems, a new kind of enzymatic biosensor for the amperometric detection of hydrogen peroxide (H2O2) was developed using biomimetic graphene capsules (GRCAPS). Horseradish peroxidase was initially encapsulated in GRCAPS using porous CaCO3 as sacrificial templates to mimic the existence form of bio-enzymes in the organisms, and then GRCAPS and graphene-poly(sodium 4-styrenesulfonate) were alternatively assembled onto the substrate of indium tin oxide for constructing multilayer films of the biosensor. Transmittance electron microscopy and field-emission scanning electron microscopy analyses proved that the GRCAPS and multilayer films were prepared. Electrochemical experiment results indicated that easy, direct electrochemistry and good catalytic activity toward H2O2 oxidation can be achieved with this biosensor. The resulting biosensor presented a wide linear range of 0.01–12 mmol l−1, a low detection limit of 3.3 μmol l−1 (S/N = 3), excellent anti-interference ability, and long-term stability as well

  19. The role of hydrogen peroxide in the deposition of cerium-based conversion coatings

    Cerium-based conversion coatings are progressing as an effective alternative to hazardous chromate-based systems used in the treatment of metal surfaces. However, there is still considerable debate over the mechanism by which these coatings are formed. Here, titrations of cerium-based conversion coating solutions were carried out in order to model the reactions that occur at the metal-solution interface during coating, with a particular emphasis on investigating the role of hydrogen peroxide (H2O2). The titration curves obtained support the proposed formation of Ce(III) peroxo complexes such as Ce(H2O2)3+ as an initial step, followed by deprotonation, oxidation and precipitation to form peroxo-containing Ce(IV) species such as Ce(IV)(O2)(OH)2. The precipitates resulting from titrations were characterised by Raman spectroscopy, X-ray diffraction and thermogravimetric analysis, confirming the presence of peroxo bonds, and nano-sized CeO2 crystallites that decreased in size with increasing H2O2 concentration. Characterisation of cerium conversion coatings on aluminium alloy surfaces confirmed the presence of peroxo species in the coatings, thereby supporting the titration model

  20. Oxidation of hydrogen peroxide by [NiIII(cyclam)]3+ in aqueous acidic media

    Sankaran Anuradha; Venkatapuram Ramanujam Vijayaraghavan

    2013-09-01

    The kinetics of oxidation of H2O2 by [NiIII(cyclam)]3+, [NiIIIL1], was studied in aqueous acidic media at 25°C and I = 0.5M (NaClO4). The [NiIIIL1] to [NiIIL1] reduction was found to be fast in the presence of Cu(II) ion than the oxidation of the cyclam ligand by ·OH. The rate constant showed an inverse acid dependence on H+ ion at the pH range 1-1.5. The presence of sulphate retards the reaction. Macrocylic ligand oxidation was followed spectrophotometrically by examining the oxidation of nickel(II) complexes of macrocyclic ligands such as 1,8-bis(2-hydroxyethyl)-1,3,6,8,10,13-hexaazacyclotetradecane (L2), -5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane (L3), rac-Me6[14]-4,11-dieneN4 (L4) by reaction with hydrogen peroxide. The rate constant for the cross reaction is discussed in terms of Marcus relationship.

  1. Gamma radiolysis of alachlor aqueous solutions in the presence of hydrogen peroxide

    The enhanced effect of gamma irradiation with hydrogen peroxide (H2O2) for alachlor degradation in an aqueous solution was first investigated in this study. The combination of gamma irradiation and H2O2 led to an enhanced effect, which remarkably increased the degradation efficiency of alachlor and the total organic carbon (TOC) removal. At a dose of 200 Gy, the degradation degree of the alachlor solution reached 81.7 and 99.2% under H2O2 concentrations of 0 and 0.1 μM, respectively. In addition, the TOC removal efficiencies of the alachlor under initial H2O2 concentrations of 0, 0.5 and 1.0 μM were 59.5, 74.8 and 83.8%, respectively, at an absorbed dose of 20 kGy. However, for higher H2O2 concentrations (greater than 1 μM), the alachlor degradation was reduced because ·OH radicals were scavenged by the H2O2. The biodegradability of alachlor solutions prior to and after treatment by gamma irradiation was also assessed using the Closed Bottle Test (CBT). The results showed enhanced biodegradability of alachlor with increasing absorbed doses.

  2. Amperometric Non-Enzymatic Hydrogen Peroxide Sensor Based on Aligned Zinc Oxide Nanorods

    Al-Hardan, Naif H.; Abdul Hamid, Muhammad Azmi; Shamsudin, Roslinda; Othman, Norinsan Kamil; Kar Keng, Lim

    2016-01-01

    Zinc oxide (ZnO) nanorods (NRs) have been synthesized via the hydrothermal process. The NRs were grown over a conductive glass substrate. A non-enzymatic electrochemical sensor for hydrogen peroxide (H2O2), based on the prepared ZnO NRs, was examined through the use of current-voltage measurements. The measured currents, as a function of H2O2 concentrations ranging from 10 μM to 700 μM, revealed two distinct behaviours and good performance, with a lower detection limit (LOD) of 42 μM for the low range of H2O2 concentrations (first region), and a LOD of 143.5 μM for the higher range of H2O2 concentrations (second region). The prepared ZnO NRs show excellent electrocatalytic activity. This enables a measurable and stable output current. The results were correlated with the oxidation process of the H2O2 and revealed a good performance for the ZnO NR non-enzymatic H2O2 sensor. PMID:27367693

  3. Facile Fabrication of a Gold Nanocluster-Based Membrane for the Detection of Hydrogen Peroxide

    Zhang, Pu; Wang, Yi; Yin, Yibing

    2016-01-01

    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. PMID:27447647

  4. Facile Fabrication of a Gold Nanocluster-Based Membrane for the Detection of Hydrogen Peroxide

    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.

  5. Hydrogen peroxide modulates abscisic acid signaling in root growth and development in Arabidopsis

    BAI Ling; ZHOU Yun; ZHANG XiaoRan; SONG ChunPeng; Gao MingQing

    2007-01-01

    Exogenous abscisic acid (ABA) can inhibit root growth and promote formation of more root hairs in the root tip of Arabidopsis. However, the molecular mechanisms that underlie root ABA signaling are largely unknown. We report here that hydrogen peroxide (H2O2) reduces the root growth of wild type,and the phenotype of H2O2 on the root growth is similar to ABA response. Meanwhile ABA-induced changes in the morphology of root system can be partly reversed by ascorbic acid in wild type and abolished in NADPH oxidase defective mutant atrbohF and atrbohC. Further, ABA can induce H2O2 accumulation in the root cells and enhance transcription level of OXI1, which is necessary for many more AOS-dependent processes such as root hair growth in Arabidopsis. Our results suggest that H2O2 as an important signal molecule is required for the ABA-regulated root growth and development in Arabidopsis.

  6. Characterizing the chemical pathways for water formation -- A deep search for hydrogen peroxide

    Parise, B; Menten, K

    2014-01-01

    In 2011, hydrogen peroxide (HOOH) was observed for the first time outside the solar system (Bergman et al., A&A, 2011, 531, L8). This detection appeared a posteriori quite natural, as HOOH is an intermediate product in the formation of water on the surface of dust grains. Following up on this detection, we present a search for HOOH in a diverse sample of sources in different environments, including low-mass protostars and regions with very high column densities, such as Infrared Dark Clouds (IRDCs). We do not detect the molecule in any other source than Oph A, and derive 3$\\sigma$ upper limits for the abundance of HOOH relative to H$_2$ lower than in Oph A for most sources. This result sheds a different light on our understanding of the detection of HOOH in Oph A, and shifts the puzzle to why this source seems to be special. Therefore we rediscuss the detection of HOOH in Oph A, as well as the implications of the low abundance of HOOH, and its similarity with the case of O$_2$. Our chemical models show th...

  7. Nuclear magnetic resonance J coupling constant polarizabilities of hydrogen peroxide: a basis set and correlation study.

    Kjaer, Hanna; Nielsen, Monia R; Pagola, Gabriel I; Ferraro, Marta B; Lazzeretti, Paolo; Sauer, Stephan P A

    2012-09-01

    In this article, we present the so far most extended investigation of the calculation of the coupling constant polarizability of a molecule. The components of the coupling constant polarizability are derivatives of the nuclear magnetic resonance (NMR) indirect nuclear spin-spin coupling constant with respect to an external electric field and play an important role for both chiral discrimination and solvation effects on NMR coupling constants. In this study, we illustrate the effects of one-electron basis sets and electron correlation both at the level of density functional theory as well as second-order polarization propagator approximation for the small molecule hydrogen peroxide, which allowed us to perform calculations with the largest available basis sets optimized for the calculation of NMR coupling constants. We find a systematic but rather slow convergence with the one-electron basis set and that augmentation functions are required. We observe also large and nonsystematic correlation effects with significant differences between the density functional and wave function theory methods. PMID:22618604

  8. Hydrogen Peroxide Induced Protein Oxidation During Storage and Lyophilization Process.

    Cheng, Weiqiang; Zheng, Xiaoyang; Yang, Mark

    2016-06-01

    Although the impact of hydrogen peroxide (HP) on proteins in liquid solutions has been studied extensively, the impact during lyophilization has been largely overlooked. The purpose of this work was to investigate the effect of HP on lyophilized proteins and HP removal by lyophilization. A protein formulation at 5 mg/mL and its placebo were spiked with HP up to 5.0 ppm and then lyophilized. HP concentration, protein oxidation, and aggregation were monitored before and after lyophilization, as well as during storage at 25°C. The lyophilization process removed on average 94.1% of HP from protein formulation, but only 72.5% from the placebo. There were also significant increases in protein oxidization and aggregation. The oxidation increment correlated with the decrease of HP concentration in both the protein formulation and placebo at all temperatures. Protein oxidation at different freezing temperatures was also studied in follow-up studies. Data from these studies suggest that (1) HP has a significant impact on oxidation and aggregation of protein during lyophilization; (2) significant oxidation can occur even when the protein formulation is frozen; (3) the oxidized protein is more prone to aggregation during lyophilization process. PMID:27238482

  9. Amperometric Non-Enzymatic Hydrogen Peroxide Sensor Based on Aligned Zinc Oxide Nanorods

    Naif H. Al-Hardan

    2016-06-01

    Full Text Available Zinc oxide (ZnO nanorods (NRs have been synthesized via the hydrothermal process. The NRs were grown over a conductive glass substrate. A non-enzymatic electrochemical sensor for hydrogen peroxide (H2O2, based on the prepared ZnO NRs, was examined through the use of current-voltage measurements. The measured currents, as a function of H2O2 concentrations ranging from 10 μM to 700 μM, revealed two distinct behaviours and good performance, with a lower detection limit (LOD of 42 μM for the low range of H2O2 concentrations (first region, and a LOD of 143.5 μM for the higher range of H2O2 concentrations (second region. The prepared ZnO NRs show excellent electrocatalytic activity. This enables a measurable and stable output current. The results were correlated with the oxidation process of the H2O2 and revealed a good performance for the ZnO NR non-enzymatic H2O2 sensor.

  10. Hypersensitivity of mouse NEIL1-knockdown cells to hydrogen peroxide during S phase

    Oxidative base damage occurs spontaneously due to reactive oxygen species generated as byproducts of respiration and other pathological processes in mammalian cells. Many oxidized bases are mutagenic and/or toxic, and most are repaired through the base excision repair pathway. Human endonuclease VIII-like protein 1 (hNEIL1) is thought to play an important role during the S phase of the cell cycle by removing oxidized bases in DNA replication fork-like (bubble) structures, and the protein level of hNEIL1 is increased in S phase. Compared with hNEIL1, there is relatively little information on the properties of the mouse ortholog mNEIL1. Since mouse cell nuclei lack endonuclease III-like protein (NTH) activity, in contrast to human cell nuclei, mNEIL1 is a major DNA glycosylase for repair of oxidized pyrimidines in mouse nuclei. In this study, we made mNEIL1-knockdown cells using an shRNA expression vector and examined the cell cycle-related variation in hydrogen peroxide (H2O2) sensitivity. Hypersensitivity to H2O2 caused by mNEIL1 knockdown was more significant in S phase than in G1 phase, suggesting that mNEIL1 has an important role during S phase, similarly to hNEIL1

  11. Styrene epoxidation with hydrogen peroxide over calcium oxide catalysts prepared from various precursors

    Qingming Gu; Dan Han; Lei Shi; Qi Sun

    2012-01-01

    A series of CaO samples were prepared by calcination of commercially available and synthesis of calcium salt precursors such as calcium acetate,carbonate,hydroxide and oxalate etc.CaO samples were found to be effective for the epoxidation of styrene using hydrogen peroxide as an oxidant in the presence of acetonitrile.To determine the influence of the physicochemical properties and surface basicity on the catalytic activity,the prepared CaO samples were characterized using thermogravimetry (TG),X-ray diffraction (XRD),scanning electron microscopy (SEM),N2-adsorption and temperature-programmed desorption of CO2 (CO2-TPD).The results indicate that the amounts of very strong basic sites and high basicity strength on CaO sample are key factors for its excellent catalytic performance.In contrast,the surface area,porosity and the surface structure of CaO sample have a relatively minor effect on the catalytic activity.CaO sample,obtained by the decomposition of Ca(OH)2,prepared by precipitating calcium nitrate with sodium hydroxide in ethylene glycol solution,exhibits the highest amount of very strong basic sites and stronger strength of basic sites,and therefore it catalyses the epoxidation of styrene with the highest rate among the tested CaO samples.Under the selected reaction conditions,the selectivity of 97.5% to styrene oxide at a conversion in excess of 99% could be obtained.

  12. Role of mitochondrial hydrogen peroxide induced by intermittent hypoxia in airway epithelial wound repair in vitro.

    Hamada, Satoshi; Sato, Atsuyasu; Hara-Chikuma, Mariko; Satooka, Hiroki; Hasegawa, Koichi; Tanimura, Kazuya; Tanizawa, Kiminobu; Inouchi, Morito; Handa, Tomohiro; Oga, Toru; Muro, Shigeo; Mishima, Michiaki; Chin, Kazuo

    2016-05-15

    The airway epithelium acts as a frontline barrier against various environmental insults and its repair process after airway injury is critical for the lung homeostasis restoration. Recently, the role of intracellular reactive oxygen species (ROS) as transcription-independent damage signaling has been highlighted in the wound repair process. Both conditions of continuous hypoxia and intermittent hypoxia (IH) induce ROS. Although IH is important in clinical settings, the roles of IH-induced ROS in the airway repair process have not been investigated. In this study, we firstly showed that IH induced mitochondrial hydrogen peroxide (H2O2) production and significantly decreased bronchial epithelial cell migration, prevented by catalase treatment in a wound scratch assay. RhoA activity was higher during repair process in the IH condition compared to in the normoxic condition, resulting in the cellular morphological changes shown by immunofluorescence staining: round cells, reduced central stress fiber numbers, pronounced cortical actin filament distributions, and punctate focal adhesions. These phenotypes were replicated by exogenous H2O2 treatment under the normoxic condition. Our findings confirmed the transcription-independent role of IH-induced intracellular ROS in the bronchial epithelial cell repair process and might have significant implications for impaired bronchial epithelial cell regeneration. PMID:27093911

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

    Qiang Zhao

    2010-02-01

    Full Text Available 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 consistency 10%, bleaching temperature 70oC, bleaching time 60 min when the charge of H2O2 was 4%, NaOH charge 2%, and molar ratio of TAED to H2O2 0.3. The pulp brightness gain reached 23.6% ISO with the optimized bleaching conditions. FTIR analysis indicated that the H2O2/TAED bleaching system can decrease carbonyl group further than that of conventional H2O2 bleaching, which contributed to the higher bleaching efficiency and final brightness. The H2O2/TAED bleaching had stronger oxidation ability on lignin than that of H2O2 bleaching.

  14. Hydrogen peroxide and glucose biosensor based on silver nanowires synthesized by polyol process.

    Yang, Xuejuan; Bai, Jing; Wang, Yinhu; Jiang, Xiue; He, Xiaoying

    2012-09-21

    Silver nanowires synthesized through a polyol process using polyvinylpyrrolidone as protection (PVP-AgNWs) were used as a new electrode material for constructing a sensor. Hydrogen peroxide (H(2)O(2)) and glucose were used as analytes to demonstrate the sensor performance of the PVP-AgNWs. It is found that the PVP-AgNWs-modified glassy carbon electrode (PVP-AgNWs/GCE) exhibits remarkable catalytic performance toward H(2)O(2) reduction. This sensor has a fast amperometric response time of less than 2 s and the catalytic current is linear over the concentration of H(2)O(2) ranging from 20 μM to 3.62 mM (R = 0.998) with a detection limit of 2.3 μM estimated on a signal-to-noise ratio of 3. A glucose biosensor was constructed by immobilizing glucose oxidase (GOD) onto the surface of the PVP-AgNWs/GCE. The resultant glucose biosensor can be used for glucose detection in human blood serum with a sensitivity of 15.86 μA mM(-1) cm(-2) and good selectivity and stability. PMID:22858619

  15. Transcriptome analysis of Bifidobacterium longum strains that show a differential response to hydrogen peroxide stress.

    Oberg, Taylor S; Ward, Robert E; Steele, James L; Broadbent, Jeff R

    2015-10-20

    Consumer and commercial interest in foods containing probiotic bifidobacteria is increasing. However, because bifidobacteria are anaerobic, oxidative stress can diminish cell viability during production and storage of bioactive foods. We previously found Bifidobacterium longum strain NCC2705 had significantly greater intrinsic and inducible resistance to hydrogen peroxide (H2O2) than strain D2957. Here, we explored the basis for these differences by examining the transcriptional responses of both strains to sub-lethal H2O2 exposure for 5- or 60-min. Strain NCC2705 had 288 genes that were differentially expressed after the 5-min treatment and 114 differentially expressed genes after the 60-min treatment. In contrast, strain D2957 had only 21 and 90 differentially expressed genes after the 5- and 60-min treatments, respectively. Both strains showed up-regulation of genes coding enzymes implicated in oxidative stress resistance, such as thioredoxin, thioredoxin reductase, peroxiredoxin, ferredoxin, glutaredoxin, and anaerobic ribonucleotide reductase, but induction levels were typically highest in NCC2705. Compared to D2957, NCC2705 also had more up-regulated genes involved in transcriptional regulation and more down-regulated genes involved in sugar transport and metabolism. These results provide a greater understanding of the molecular basis for oxidative stress resistance in B. longum and the factors that contribute to strain-to-strain variability in survival in bioactive food products. PMID:26299205

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

    Cheong, Chong-Un; Yeh, Ching-Sheng; Hsieh, Yi-Wen; Lee, Ying-Ray; Lin, Mei-Ying; Chen, Chung-Yi; Lee, Chien-Hsing

    2016-01-01

    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. PMID:27409597

  17. Nitrogen-doped graphene-silver nanodendrites for the non-enzymatic detection of hydrogen peroxide

    Highlights: • N-graphene/Ag nanodendrities by electrophoretic and electrochemical deposition. • Support of N-graphene shows efficient electrocatalytic activity toward H2O2 reduction. • The fabricated non-enzymatic H2O2 electrochemical sensor improved in the presence of Ag. - Abstract: An organic-metal hybrid film based on nitrogen-doped graphene-silver nanodendrites (Ag-NG) was fabricated on an indium tin oxide (ITO) electrode using a simple electrophoretic and electrochemical sequential deposition approach. The microwave-assisted method was utilized for the synthesis of nitrogen-doped graphene. This method involves a three-step process consisting of graphite oxidation, exfoliation, and finally chemical reduction with the use of hydrazine as the reducing agent, which leads to the simultaneous reduction of graphene oxide and production of nitrogen-doped graphene. The morphology and structure of the as-fabricated electrode were determined by X-ray diffraction, field emission electron microscopy and transmission electron microscopy. The as-prepared Ag-NG-modified ITO electrode exhibited superior electrocatalytic activity toward hydrogen peroxide (H2O2) reduction, with a wide linear detection range of 100 μM to 80 mM (r = 0.9989) and a detection limit of 0.26 μM with a signal-to-noise ratio of 3. Furthermore, the fabricated non-enzymatic H2O2 electrochemical sensor exhibited excellent stability and reproducibility

  18. Synthesis of dendritic silver nanostructures and their application in hydrogen peroxide electroreduction

    Well-defined silver (Ag) dendritic nanostructures were successfully synthesized by electrodeposition without the use of any template or surfactant. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to investigate the as-prepared Ag nanomaterials. These dendrites are aggregates of Ag nanoparticles, which are highly crystalline in nature. The concentration of AgNO3 affects the shape of the nanoparticles. In addition, the electrochemical properties of the Ag dendrite-modified glassy carbon electrode (Ag/GC) were characterized by cyclic voltammetry and chronoamperometry. Results indicated that the as-obtained Ag dendrites exhibited favorable electroreduction activity towards oxygen (O2) and hydrogen peroxide (H2O2). When used as a sensor, the Ag/GC electrode exhibited a wide linear range of 0.005-12 mM H2O2, with a remarkable sensitivity of 7.39 μA/mM, a detection limit of 0.5 μM, estimated at a signal-to-noise ratio of 3, and a rapid response time (within 5 s). Moreover, the electrode showed good reproducibility, anti-interferant ability and long-term stability.

  19. Redox Response of Reduced Graphene Oxide-Modified Glassy Carbon Electrodes to Hydrogen Peroxide and Hydrazine

    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.

  20. Determination of hydrogen peroxide using a Prussian Blue modified macroporous gold electrode

    We describe an electrochemical sensor for hydrogen peroxide (H2O2) that is making use of Prussian Blue (PB) electrodeposited on a macroporous (mp) gold skeleton electrode. An mp-Cu film was first prepared as a template and the converted into an mp-Au film through a replacement reaction without destructing the structure. Next, a layer of PB was electrochemically deposited on the surface of the mp-Au film. The surface morphology of the electrode was characterized by scanning electron microscopy. Attenuated total reflection infrared spectroscopy and X-ray photoelectron spectroscopy were applied to confirm the structural features. The mp-PB/Au film electrode displays high electro-catalytic activity for the reduction of H2O2 at a working potential of −50 mV (vs. Ag/AgCl) and is very stable. It has a linear response to H2O2 in the 50 μM to 11.3 mM concentration range and a sensitivity of 767 μA∙mM−1 cm−2. The electrode also revealed good selectivity in the presence of electro-active species such as ascorbic acid and uric acid. (author)