Oxidation of hydrogen peroxide by [Ni (cyclam)] in aqueous acidic ...

Indian Academy of Sciences (India)

Oxidation of hydrogen peroxide by tris(2,2 -bipyridine) and tris(4,4 -dimethyl-2,2 - bipyridine) complexes of osmium(III), iron(III), ruthenium(III), and nickel(III) studied in acidic and neutral aqueous media, show an inverse acid depen- dence over the pH the range 6.0–8.5.12 Kinetic mea- surements with an excess of H2O2 ...

Kinetic Modeling of Methionine Oxidation in Monoclonal Antibodies from Hydrogen Peroxide Spiking Studies.

Science.gov (United States)

Hui, Ada; Lam, Xanthe M; Kuehl, Christopher; Grauschopf, Ulla; Wang, Y John

2015-01-01

When isolator technology is applied to biotechnology drug product fill-finish process, hydrogen peroxide (H2O2) spiking studies for the determination of the sensitivity of protein to residual peroxide in the isolator can be useful for assessing a maximum vapor phase hydrogen peroxide (VPHP) level. When monoclonal antibody (mAb) drug products were spiked with H2O2, an increase in methionine (Met 252 and Met 428) oxidation in the Fc region of the mAbs with a decrease in H2O2 concentration was observed for various levels of spiked-in peroxide. The reaction between Fc-Met and H2O2 was stoichiometric (i.e., 1:1 molar ratio), and the reaction rate was dependent on the concentrations of mAb and H2O2. The consumption of H2O2 by Fc-Met oxidation in the mAb followed pseudo first-order kinetics, and the rate was proportional to mAb concentration. The extent of Met 428 oxidation was half of that of Met 252, supporting that Met 252 is twice as reactive as Met 428. Similar results were observed for free L-methionine when spiked with H2O2. However, mAb formulation excipients may affect the rate of H2O2 consumption. mAb formulations containing trehalose or sucrose had faster H2O2 consumption rates than formulations without the sugars, which could be the result of impurities (e.g., metal ions) present in the excipients that may act as catalysts. Based on the H2O2 spiking study results, we can predict the amount Fc-Met oxidation for a given protein concentration and H2O2 level. Our kinetic modeling of the reaction between Fc-Met oxidation and H2O2 provides an outline to design a H2O2 spiking study to support the use of VPHP isolator for antibody drug product manufacture. Isolator technology is increasing used in drug product manufacturing of biotherapeutics. In order to understand the impact of residual vapor phase hydrogen peroxide (VPHP) levels on protein product quality, hydrogen peroxide (H2O2) spiking studies may be performed to determine the sensitivity of monoclonal antibody

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

KAUST Repository

Alshammari, Y.M.

2015-01-01

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

Propylene epoxydation with hydrogen peroxide in acidic conditions

NARCIS (Netherlands)

Kertalli, E.; Rijnsoever, L.S.; Paunovic, V.; Schouten, J.C.; Neira d'Angelo, M.F.; Nijhuis, T.A.

2016-01-01

In the present work, the epoxidation of propylene with hydrogen peroxide in the presence of acids and halides is studied. The presence of acids and halides is indispensable for increasing the selectivity of the direct synthesis of hydrogen peroxide, the first step of the direct propylene oxide

Conversion of Aryl Iodides into Aryliodine(III Dichlorides by an Oxidative Halogenation Strategy Using 30% Aqueous Hydrogen Peroxide in Fluorinated Alcohol

Directory of Open Access Journals (Sweden)

Ajda Podgoršek

2010-04-01

Full Text Available Oxidative chlorination with HCl/H2O2 in 1,1,1-trifluoroethanol was used to transform aryl iodides into aryliodine(III dihalides. In this instance 1,1,1-trifluoroethanol is not only the reaction medium, but is also an activator of hydrogen peroxide for the oxidation of hydrochloric acid to molecular chlorine. Aryliodine(III dichlorides were formed in 72–91% isolated yields in the reaction of aryl iodides with 30% aqueous hydrogen peroxide and hydrochloric acid at ambient temperature. A study of the effect that substituents on the aromatic ring have on the formation and stability of aryliodine(III dichlorides shows that the transformation is easier to achieve in the presence of the electron-donating groups (i.e. methoxy, but in this case the products rapidly decompose under the reported reaction conditions to form chlorinated arenes. The results suggest that oxidation of hydrogen chloride with hydrogen peroxide is the initial reaction step, while direct oxidation of aryl iodide with hydrogen peroxide is less likely to occur.

Destruction of oxalate by reaction with hydrogen peroxide. [Hydrazine oxalate

Energy Technology Data Exchange (ETDEWEB)

Mailen, J.C.; Tallent, O.K.; Arwood, P.C.

1981-09-01

The destruction of oxalate by oxidation to carbon dioxide using hydrogen peroxide was studied as an alternative method for the disposal of oxalate in connection with the possible use of an aqueous hydrazine oxalate solution as a scrubbing agent for solvent cleanup in processes for the recovery of uranium, plutonium, and thorium by solvent extraction. The rate of oxidation of oxalate by hydrogen peroxide in acid solution at the reflux temperature was adequate for process application; reaction half-times at 100/sup 0/C were less than one hour when the hydrogen peroxide concentration was greater than 0.5 M. The reaction was first order with respect to both the oxalate and hydrogen peroxide concentrations and had an activation energy of 58.7 kJ/g-mol. The rate increased with the hydrogen ion concentration as (H/sup +/)/sup 0/ /sup 3/ but was not significantly affected by the presence of 100 ppM of uranium or copper in solution. In the near-neutral hydrazine oxalate solutions, the reaction of either component with hydrogen peroxide was too slow for process application.

Phenol degradation in aqueous solution by photolytic oxidation with ozone and/or hydrogen peroxide

International Nuclear Information System (INIS)

Koepp, T.; Koether, M.; Brueckner, B.; Radeke, K.H.

1993-01-01

The removal of phenol in an aqueous solution as a typical pollutant by oxidation using ozone and hydrogen peroxide under ultraviolet irradiation has been studied. Both the O 3 /UV and the H 2 O 2 /UV method can be powerful to decompose the total organic carbon (TOC) to carbon dioxide and water, but the first method is more effective. In the case of H 2 O 2 /UV method a strong overdose on H 2 O 2 is necessary to remove TOC effectively, however, a favourable H 2 O 2 concentration exists. This is probably caused by undesired parallel reactions of hydrogen peroxide. The simultaneous use of ozone and hydrogen peroxide accelerates the removal of TOC in the first third of experiment in comparison to the O 3 /UV method, but the time of total decomposition of TOC is delayed. A change in measured kinetics of ozone consumption by organic molecules corresponds well with the time of total transformation of aromatic into aliphatic substances. (orig.)

Electrochemical behaviour of platinum in hydrogen peroxide solution (1963)

International Nuclear Information System (INIS)

Prost, G.H.

1963-06-01

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) [fr

Hydrogen peroxide safety issues

International Nuclear Information System (INIS)

Conner, W.V.

1993-01-01

A literature survey was conducted to review the safety issues involved in handling hydrogen peroxide solutions. Most of the information found in the literature is not directly applicable to conditions at the Rocky Flats Plant, but one report describes experimental work conducted previously at Rocky Flats to determine decomposition reaction-rate constants for hydrogen peroxide solutions. Data from this report were used to calculate decomposition half-life times for hydrogen peroxide in solutions containing several decomposition catalysts. The information developed from this survey indicates that hydrogen peroxide will undergo both homogeneous and heterogeneous decomposition. The rate of decomposition is affected by temperature and the presence of catalytic agents. Decomposition of hydrogen peroxide is catalyzed by alkalies, strong acids, platinum group and transition metals, and dissolved salts of transition metals. Depending upon conditions, the consequence of a hydrogen peroxide decomposition can range from slow evolution of oxygen gas to a vapor, phase detonation of hydrogen peroxide vapors

Diesel autothermal reforming with hydrogen peroxide for low-oxygen environments

International Nuclear Information System (INIS)

Han, Gwangwoo; Lee, Sangho; Bae, Joongmyeon

2015-01-01

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.%)/Ce 0.9 Gd 0.1 O 2−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

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

Energy Technology Data Exchange (ETDEWEB)

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

2011-07-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Wilbraham, Richard J., E-mail: r.wilbraham@lancaster.ac.uk [The Lloyd’s Register Foundation Centre for Nuclear Engineering, Engineering Department, Lancaster University, Bailrigg, Lancashire LA1 4YR (United Kingdom); Boxall, Colin, E-mail: c.boxall@lancaster.ac.uk [The Lloyd’s Register Foundation Centre for Nuclear Engineering, Engineering Department, Lancaster University, Bailrigg, Lancashire LA1 4YR (United Kingdom); Goddard, David T., E-mail: dave.t.goddard@nnl.co.uk [National Nuclear Laboratory, Preston Laboratory, Springfields, Preston, Lancashire PR4 0XJ (United Kingdom); Taylor, Robin J., E-mail: robin.j.taylor@nnl.co.uk [National Nuclear Laboratory, Central Laboratory, Seascale, Cumbria CA20 1PG (United Kingdom); Woodbury, Simon E., E-mail: simon.woodbury@nnl.co.uk [National Nuclear Laboratory, Central Laboratory, Seascale, Cumbria CA20 1PG (United Kingdom)

2015-09-15

Highlights: • The first report of the presence of both UO{sub 2} and polymeric UO{sub 2}{sup 2+} in the same electrodeposited U oxide sample. • The action of H{sub 2}O{sub 2} on electrodeposited U oxides is described using corrosion based concepts. • Electrodeposited U oxide freely dissolves at hydrogen peroxide concentrations <100 μmol dm{sup −3}. • At [H{sub 2}O{sub 2}] > 0.1 mmol dm{sup −3} dissolution is inhibited by formation of a studtite passivation layer. • At [H{sub 2}O{sub 2}] ⩾ 1 mol dm{sup −3} studtite formation competes with uranyl–peroxide complex formation. - Abstract: For the first time the effect of hydrogen peroxide on the dissolution of electrodeposited uranium oxide films on 316L stainless steel planchets (acting as simulant uranium-contaminated metal surfaces) has been studied. Analysis of the H{sub 2}O{sub 2}-mediated film dissolution processes via open circuit potentiometry, alpha counting and SEM/EDX imaging has shown that in near-neutral solutions of pH 6.1 and at [H{sub 2}O{sub 2}] ⩽ 100 μmol dm{sup −3} the electrodeposited uranium oxide layer is freely dissolving, the associated rate of film dissolution being significantly increased over leaching of similar films in pH 6.1 peroxide-free water. At H{sub 2}O{sub 2} concentrations between 1 mmol dm{sup −3} and 0.1 mol dm{sup −3}, formation of an insoluble studtite product layer occurs at the surface of the uranium oxide film. In analogy to corrosion processes on common metal substrates such as steel, the studtite layer effectively passivates the underlying uranium oxide layer against subsequent dissolution. Finally, at [H{sub 2}O{sub 2}] > 0.1 mol dm{sup −3} the uranium oxide film, again in analogy to common corrosion processes, behaves as if in a transpassive state and begins to dissolve. This transition from passive to transpassive behaviour in the effect of peroxide concentration on UO{sub 2} films has not hitherto been observed or explored, either in terms

Electrocatalytic oxidation of hydrogen peroxide on a platinum electrode in the imitation of oxidative drug metabolism of lidocaine.

Science.gov (United States)

Nouri-Nigjeh, Eslam; Bruins, Andries P; Bischoff, Rainer; Permentier, Hjalmar P

2012-10-21

Electrochemistry in combination with mass spectrometry has shown promise as a versatile technique not only in the analytical assessment of oxidative drug metabolism, but also for small-scale synthesis of drug metabolites. However, electrochemistry is generally limited to reactions initiated by direct electron transfer. In the case of substituted-aromatic compounds, oxidation proceeds through a Wheland-type intermediate where resonance stabilization of the positive charge determines the regioselectivity of the anodic substitution reaction, and hence limits the extent of generating drug metabolites in comparison with in vivo oxygen insertion reactions. In this study, we show that the electrocatalytic oxidation of hydrogen peroxide on a platinum electrode generates reactive oxygen species, presumably surface-bound platinum-oxo species, which are capable of oxygen insertion reactions in analogy to oxo-ferryl radical cations in the active site of Cytochrome P450. Electrochemical oxidation of lidocaine at constant potential in the presence of hydrogen peroxide produces both 3- and 4-hydroxylidocaine, suggesting reaction via an arene oxide rather than a Wheland-type intermediate. No benzylic hydroxylation was observed, thus freely diffusing radicals do not appear to be present. The results of the present study extend the possibilities of electrochemical imitation of oxidative drug metabolism to oxygen insertion reactions.

Probing skin interaction with hydrogen peroxide using diffuse reflectance spectroscopy

International Nuclear Information System (INIS)

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 H 2 O 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

Kinetics of Oxidation of Cobalt(III Complexes of a Acids by Hydrogen Peroxide in the Presence of Surfactants

Directory of Open Access Journals (Sweden)

Mansur Ahmed

2008-01-01

Full Text Available Hydrogen peroxide oxidation of pentaamminecobalt(III complexes of α-hydroxy acids at 35°C in micellar medium has been attempted. In this reaction the rate of oxidation shows first order kinetics each in [cobalt(III] and [H2O2]. Hydrogen peroxide induced electron transfer in [(NH35 CoIII-L]2+ complexes of α-hydroxy acids readily yields 100% of cobalt(II with nearly 100% of C-C bond cleavage products suggesting that it behaves mainly as one equivalent oxidant in micellar medium. With unbound ligand also it behaves only as C-C cleavage agent rather than C-H cleavage agent. With increasing micellar concentration an increase in the rate is observed.

Hydrogen peroxide kinetics in water radiolysis

Science.gov (United States)

Iwamatsu, Kazuhiro; Sundin, Sara; LaVerne, Jay A.

2018-04-01

The kinetics of the formation and reaction of hydrogen peroxide in the long time γ- radiolysis of water is examined using a combination of experiment with model calculations. Escape yields of hydrogen peroxide on the microsecond time scale are easily measured with added radical scavengers even with substantial amounts of initial added hydrogen peroxide. The γ-radiolysis of aqueous hydrogen peroxide solutions without added radical scavengers reach a steady state limiting concentration of hydrogen peroxide with increasing dose, and that limit is directly proportional to the initial concentration of added hydrogen peroxide. The dose necessary to reach that limiting hydrogen peroxide concentration is also proportional to the initial concentration, but dose rate has a very small effect. The addition of molecular hydrogen to aqueous solutions of hydrogen peroxide leads to a decrease in the high dose limiting hydrogen peroxide concentration that is linear with the initial hydrogen concentration, but the amount of decrease is not stoichiometric. Proton irradiations of solutions with added hydrogen peroxide and hydrogen are more difficult to predict because of the decreased yields of radicals; however, with a substantial increase in dose rate there is a sufficient decrease in radical yields that hydrogen addition has little effect on hydrogen peroxide decay.

Gold-catalyzed oxidation of substituted phenols by hydrogen peroxide

KAUST Repository

Cheneviere, Yohan

2010-10-20

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

Probing skin interaction with hydrogen peroxide using diffuse reflectance spectroscopy

Energy Technology Data Exchange (ETDEWEB)

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

2008-01-07

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

Physico Chemical Characteristic of Kappa Carrageenan Degraded Using Hydrogen Peroxide

Directory of Open Access Journals (Sweden)

Rizky Febriansyah Siregar

2017-02-01

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

Saccharomyces cerevisiae has distinct adaptive responses to both hydrogen peroxide and menadione.

OpenAIRE

Jamieson, D J

1992-01-01

Treatment of Saccharomyces cerevisiae cells with low concentrations of either hydrogen peroxide or menadione (a superoxide-generating agent) induces adaptive responses which protect cells from the lethal effects of subsequent challenge with higher concentrations of these oxidants. Pretreatment with menadione is protective against cell killing by hydrogen peroxide; however, pretreatment with hydrogen peroxide is unable to protect cells from subsequent challenge with menadione. This suggests th...

Oxidation and Destruction of Polyvinyl Alcohol under the Combined Action of Ozone-Oxygen Mixture and Hydrogen Peroxide

Science.gov (United States)

Zimin, Yu. S.; Kutlugil'dina, G. G.; Mustafin, A. G.

2018-03-01

The oxidative transformations of a polyvinyl alcohol in aqueous solutions are studied under the simultaneous action of the two oxidizing agents, an ozone-oxygen mixture and a hydrogen peroxide. Effective parameters a and b, which characterize the first and second channels of carboxyl group accumulation, respectively, grow linearly upon an increase in the initial concentration of H2O2. After the temperature dependence of a and b parameters (331-363 K) in a PVA + O3 + O2 + H2O2 + H2O reaction system is studied, the parameters of the activation of COOH group accumulation are found (where PVA is a polyvinyl alcohol). New data on the effect process conditions (length of oxidation, temperature, and hydrogen peroxide concentration) have on the degree of destructive transformations of polyvinyl alcohol in the investigated reaction system are obtained.

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

Directory of Open Access Journals (Sweden)

Alireza Haghighat Mamaghani

2013-01-01

Full Text Available An effective oxidative system consisting of hydrogen peroxide, formic acid, and sulfuric acid followed by an extractive stage were implemented to remove dibenzothiophene in the simulated fuel oil. The results revealed such a great performance in the case of H2O2 in the presence of formic and sulfuric acids that led to the removal of sulfur compounds. Sulfuric acid was employed to increase the acidity of media as well as catalytic activity together with formic acid. The oxidation reaction was followed by a liquid-liquid extraction stage using acetonitrile as a polar solvent to remove produced sulfones from the model fuel. The impact of operating parameters including the molar ratio of formic acid to sulfur (, hydrogen peroxide to sulfur (, and the time of reaction was investigated using Box-Behnken experimental design for oxidation of the model fuel. A significant quadratic model was introduced for the sulfur removal as a function of effective parameters by the statistic analysis.

Dissolution kinetics of lead telluride in alkali solutions of hydrogen peroxide

International Nuclear Information System (INIS)

Danilova, M.G.; Sveshnikova, L.L.; Stavitskaya, T.A.; Repinskij, S.M.

1991-01-01

Dissolution kinetics of lead telluride in alkali solutions of hydrogen peroxide was investigated. Dependences of change of PbTe dissolution rate on concentration of hydrogen peroxide and alkali in the solution were obtained. It is shown that dissolution rate of lead telluride is affected by dissolution rate of lead oxide, representing the product of ReTe dissolution. The obtained regularities can be explained by change of solution structure with increase of KOH concentration and by the state of hydrogen peroxide in the solution

Sodium Borohydride/Hydrogen Peroxide Fuel Cells For Space Application

Science.gov (United States)

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

2006-01-01

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

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

Science.gov (United States)

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

2016-12-20

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

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

International Nuclear Information System (INIS)

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

2012-01-01

This review describes homogeneous and heterogeneous catalytic reduction of dioxygen with metal complexes focusing on the catalytic two-electron reduction of dioxygen to produce hydrogen peroxide. Whether two-electron reduction of dioxygen to produce hydrogen peroxide or four-electron O 2 -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 O 2 , 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.

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

Science.gov (United States)

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

2012-11-01

This review describes homogeneous and heterogeneous catalytic reduction of dioxygen with metal complexes focusing on the catalytic two-electron reduction of dioxygen to produce hydrogen peroxide. Whether two-electron reduction of dioxygen to produce hydrogen peroxide or four-electron O 2 -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 O 2 , 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.

Protective effect of Rhus coriaria fruit extracts against hydrogen peroxide-induced oxidative stress in muscle progenitors and zebrafish embryos

Directory of Open Access Journals (Sweden)

Fadia Najjar

2017-12-01

Full Text Available Background and Purpose Oxidative stress is involved in normal and pathological functioning of skeletal muscle. Protection of myoblasts from oxidative stress may improve muscle contraction and delay aging. Here we studied the effect of R. coriaria sumac fruit extract on human myoblasts and zebrafish embryos in conditions of hydrogen peroxide-induced oxidative stress. Study Design and Methods Crude ethanolic 70% extract (CE and its fractions was obtained from sumac fruits. The composition of sumac ethyl acetate EtOAc fraction was studied by 1H NMR. The viability of human myoblasts treated with CE and the EtOAc fraction was determined by trypan blue exclusion test. Oxidative stress, cell cycle and adhesion were analyzed by flow cytometry and microscopy. Gene expression was analyzed by qPCR. Results The EtOAc fraction (IC50 2.57 µg/mL had the highest antioxidant activity and exhibited the best protective effect against hydrogen peroxide-induced oxidative stress. It also restored cell adhesion. This effect was mediated by superoxide dismutase 2 and catalase. Pre-treatment of zebrafish embryos with low concentrations of the EtOAc fraction protected them from hydrogen peroxide-induced death in vivo. 1H NMR analysis revealed the presence of gallic acid in this fraction. Conclusion Rhus coriaria extracts inhibited or slowed down the progress of skeletal muscle atrophy by decreasing oxidative stress via superoxide dismutase 2 and catalase-dependent mechanisms.

Hydrogen peroxide induced loss of heterozygosity correlates with replicative lifespan and mitotic asymmetry in Saccharomyces cerevisiae

Science.gov (United States)

Jackson, Erin D.; Parker, Meighan C.; Gupta, Nilin; Rodrigues, Jenny

2016-01-01

Cellular aging in Saccharomyces cerevisiae can lead to genomic instability and impaired mitotic asymmetry. To investigate the role of oxidative stress in cellular aging, we examined the effect of exogenous hydrogen peroxide on genomic instability and mitotic asymmetry in a collection of yeast strains with diverse backgrounds. We treated yeast cells with hydrogen peroxide and monitored the changes of viability and the frequencies of loss of heterozygosity (LOH) in response to hydrogen peroxide doses. The mid-transition points of viability and LOH were quantified using sigmoid mathematical functions. We found that the increase of hydrogen peroxide dependent genomic instability often occurs before a drop in viability. We previously observed that elevation of genomic instability generally lags behind the drop in viability during chronological aging. Hence, onset of genomic instability induced by exogenous hydrogen peroxide treatment is opposite to that induced by endogenous oxidative stress during chronological aging, with regards to the midpoint of viability. This contrast argues that the effect of endogenous oxidative stress on genome integrity is well suppressed up to the dying-off phase during chronological aging. We found that the leadoff of exogenous hydrogen peroxide induced genomic instability to viability significantly correlated with replicative lifespan (RLS), indicating that yeast cells’ ability to counter oxidative stress contributes to their replicative longevity. Surprisingly, this leadoff is positively correlated with an inverse measure of endogenous mitotic asymmetry, indicating a trade-off between mitotic asymmetry and cell’s ability to fend off hydrogen peroxide induced oxidative stress. Overall, our results demonstrate strong associations of oxidative stress to genomic instability and mitotic asymmetry at the population level of budding yeast. PMID:27833823

Electrochemical Synthesis of Polypyrrole, Reduced Graphene Oxide, and Gold Nanoparticles Composite and Its Application to Hydrogen Peroxide Biosensor

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Baoyan Wu

2016-11-01

Full Text Available Here we report a facile eco-friendly one-step electrochemical approach for the fabrication of a polypyrrole (PPy, reduced graphene oxide (RGO, and gold nanoparticles (nanoAu biocomposite on a glassy carbon electrode (GCE. The electrochemical behaviors of PPy–RGO–nanoAu and its application to electrochemical detection of hydrogen peroxide were investigated by cyclic voltammetry. Graphene oxide and pyrrole monomer were first mixed and casted on the surface of a cleaned GCE. After an electrochemical processing consisting of the electrooxidation of pyrrole monomer and simultaneous electroreduction of graphene oxide and auric ions (Au3+ in aqueous solution, a PPy–RGO–nanoAu biocomposite was synthesized on GCE. Each component of PPy–RGO–nanoAu is electroactive without non-electroactive substance. The obtained PPy–RGO–nanoAu/GCE exhibited high electrocatalytic activity toward hydrogen peroxide, which allows the detection of hydrogen peroxide at a negative potential of about −0.62 V vs. SCE. The amperometric responses of the biosensor displayed a sensitivity of 40 µA/mM, a linear range of 32 µM–2 mM, and a detection limit of 2.7 µM (signal-to-noise ratio = 3 with good stability and acceptable reproducibility and selectivity. The results clearly demonstrate the potential of the as-prepared PPy–RGO–nanoAu biocomposite for use as a highly electroactive matrix for an amperometric biosensor.

Epoxidation of natural limonene extracted from orange peels with hydrogen peroxide over Ti-MCM-41 catalyst

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Wróblewska Agnieszka

2018-03-01

Full Text Available The paper presents the oxidation of natural limonene (extracted from waste orange peels by 60 wt% hydrogen peroxide, in the presence of Ti-MCM-41 catalyst and in methanol as the solvent. The aim of the research was to develop the most favorable technological parameters for the process of limonene oxidation (temperature, molar ratio of limonene to hydrogen peroxide, methanol concentration, Ti-MCM-41 catalyst content and reaction time by analyzing changes in the main functions describing this process: the conversion of limonene, selectivities of appropriate products, the conversion of hydrogen peroxide and the effective conversion of hydrogen peroxide. The process is environmentally friendly process and it uses renewable raw material - limonene and a safe oxidant -hydrogen peroxide. During the study, very valuable oxygenated derivatives of limonene were obtained: 1,2-epoxylimonene, its diol, carvone, carveol, and perillyl alcohol. These compounds are used in medicine, cosmetics, perfumery, food and polymers industries.

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

Science.gov (United States)

Serata, Masaki; Kiwaki, Mayumi; Iino, Tohru

2016-11-01

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

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

Science.gov (United States)

Wilbraham, Richard J.; Boxall, Colin; Goddard, David T.; Taylor, Robin J.; Woodbury, Simon E.

2015-09-01

For the first time the effect of hydrogen peroxide on the dissolution of electrodeposited uranium oxide films on 316L stainless steel planchets (acting as simulant uranium-contaminated metal surfaces) has been studied. Analysis of the H2O2-mediated film dissolution processes via open circuit potentiometry, alpha counting and SEM/EDX imaging has shown that in near-neutral solutions of pH 6.1 and at [H2O2] ⩽ 100 μmol dm-3 the electrodeposited uranium oxide layer is freely dissolving, the associated rate of film dissolution being significantly increased over leaching of similar films in pH 6.1 peroxide-free water. At H2O2 concentrations between 1 mmol dm-3 and 0.1 mol dm-3, formation of an insoluble studtite product layer occurs at the surface of the uranium oxide film. In analogy to corrosion processes on common metal substrates such as steel, the studtite layer effectively passivates the underlying uranium oxide layer against subsequent dissolution. Finally, at [H2O2] > 0.1 mol dm-3 the uranium oxide film, again in analogy to common corrosion processes, behaves as if in a transpassive state and begins to dissolve. This transition from passive to transpassive behaviour in the effect of peroxide concentration on UO2 films has not hitherto been observed or explored, either in terms of corrosion processes or otherwise. Through consideration of thermodynamic solubility product and complex formation constant data, we attribute the transition to the formation of soluble uranyl-peroxide complexes under mildly alkaline, high [H2O2] conditions - a conclusion that has implications for the design of both acid minimal, metal ion oxidant-free decontamination strategies with low secondary waste arisings, and single step processes for spent nuclear fuel dissolution such as the Carbonate-based Oxidative Leaching (COL) process.

Detection of hydrogen peroxide with graphyne

Science.gov (United States)

Majidi, R.; Karami, A. R.

2013-12-01

The effect of hydrogen peroxide on the electronic properties of graphyne has been investigated to explore the possibility of using graphyne based biosensor. We have used density functional theory to study the electronic properties of γ-graphyne in the presence of different number of hydrogen peroxide. The optimal adsorption position, orientation, and distance of hydrogen peroxide adsorbed on the graphyne sheet have been determined by calculating adsorption energy. It is found that γ-graphyne which is an intrinsic semiconductor becomes an n-type semiconductor due to the presence of hydrogen peroxide. The energy band gap of γ-graphyne is decreased by increasing the number of hydrogen peroxide. The results demonstrate that γ-graphyne is a promising candidate for biosensor application because of its electrical sensitivity to hydrogen peroxide.

A reagentless non-enzymatic hydrogen peroxide sensor presented using electrochemically reduced graphene oxide modified glassy carbon electrode

Energy Technology Data Exchange (ETDEWEB)

Mutyala, Sankararao; Mathiyarasu, Jayaraman, E-mail: al_mathi@yahoo.com

2016-12-01

Herein, we report a simple, facile and reproducible non-enzymatic hydrogen peroxide (H{sub 2}O{sub 2}) sensor using electrochemically reduced graphene oxide (ERGO) modified glassy carbon electrode (GCE). The modified electrode was characterized by Fourier transform infrared (FT-IR), UV–Visible, scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. Cyclic voltammetric (CV) analysis revealed that ERGO/GCE exhibited virtuous charge transfer properties for a standard redox systems and showed excellent performance towards electroreduction of H{sub 2}O{sub 2}. Amperometric study using ERGO/GCE showed high sensitivity (0.3 μA/μM) and faster response upon the addition of H{sub 2}O{sub 2} at an applied potential of − 0.25 V vs. Ag/AgCl. The detection limit is assessed to be 0.7 μM (S/N = 3) and the time to reach a stable study state current is < 3 s for a linear range of H{sub 2}O{sub 2} concentration (1–16 μM). In addition, the modified electrode exhibited good reproducibility and long-term stability. - Graphical abstract: We presented a reagentless non-enzymatic hydrogen peroxide sensor using electrochemically reduced graphene oxide material. - Highlights: • A facile green procedure proposed for high quality graphene synthesis using electrochemical reduction of graphene oxide • A simple, facile and reagentless non-enzymatic hydrogen peroxide sensor developed using ERGO/GCE. • ERGO/GCE exhibited high sensitivity, selectivity and finite limit of detection for H{sub 2}O{sub 2} sensing at low overpotential. • ERGO/GCE exhibited long term stability and good reproducibility.

A reagentless non-enzymatic hydrogen peroxide sensor presented using electrochemically reduced graphene oxide modified glassy carbon electrode

International Nuclear Information System (INIS)

Mutyala, Sankararao; Mathiyarasu, Jayaraman

2016-01-01

Herein, we report a simple, facile and reproducible non-enzymatic hydrogen peroxide (H 2 O 2 ) sensor using electrochemically reduced graphene oxide (ERGO) modified glassy carbon electrode (GCE). The modified electrode was characterized by Fourier transform infrared (FT-IR), UV–Visible, scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. Cyclic voltammetric (CV) analysis revealed that ERGO/GCE exhibited virtuous charge transfer properties for a standard redox systems and showed excellent performance towards electroreduction of H 2 O 2 . Amperometric study using ERGO/GCE showed high sensitivity (0.3 μA/μM) and faster response upon the addition of H 2 O 2 at an applied potential of − 0.25 V vs. Ag/AgCl. The detection limit is assessed to be 0.7 μM (S/N = 3) and the time to reach a stable study state current is < 3 s for a linear range of H 2 O 2 concentration (1–16 μM). In addition, the modified electrode exhibited good reproducibility and long-term stability. - Graphical abstract: We presented a reagentless non-enzymatic hydrogen peroxide sensor using electrochemically reduced graphene oxide material. - Highlights: • A facile green procedure proposed for high quality graphene synthesis using electrochemical reduction of graphene oxide • A simple, facile and reagentless non-enzymatic hydrogen peroxide sensor developed using ERGO/GCE. • ERGO/GCE exhibited high sensitivity, selectivity and finite limit of detection for H 2 O 2 sensing at low overpotential. • ERGO/GCE exhibited long term stability and good reproducibility.

Negative Effect of Calcination to Catalytic Performance of Coal Char-loaded TiO2 Catalyst in Styrene Oxidation with Hydrogen Peroxide as Oxidant

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Mukhamad Nurhadi

2018-01-01

How to Cite: Nurhadi, M., Kusumawardani, R., Nur, H. (2018. Negative Effect of Calcination to Catalytic Performance of Coal Char-loaded TiO2 Catalyst in Styrene Oxidation with Hydrogen Peroxide as Oxidant. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (1: 113-118 (doi:10.9767/bcrec.13.1.1171.113-118

Oxidative stress biomarkers in different tissues of rainbow trout (Oncorhynchus mykiss exposed to Disinfectant-CIP formulated with peracetic acid and hydrogen peroxide

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Tkachenko Halyna

2014-09-01

Full Text Available The aim of study was to determine the effects of exposure to the product DEZYNFEKTANT-CIP (Eng. - Disinfectant-CIP, which is formulated with peracetic acid and hydrogen peroxide, on oxidative stress biomarkers (lipid peroxidation (LPO levels and the carbonyl content of oxidatively modified proteins and antioxidant defenses (superoxide dismutase (SOD, catalase (CAT, glutathione reductase (GR, glutathione peroxidase (GPx, total antioxidant capacity in muscle, gill, hepatic, and cardiac tissues of rainbow trout, Oncorhynchus mykiss (Walbaum. LPO and carbonyl contents changed with tissue type. Exposure to Disinfectant-CIP led to a significant decrease in LPO in muscle tissues and carbonyl content in muscle and gill tissues. The inhibition of SOD and CAT activity in muscle, hepatic, and cardiac tissues was observed probably because of increased oxidative stress during disinfection; however, hepatic and cardiac GPx activity increased in an attempt to counteract oxidative stress. We suggest that oxidative stress during the oxidation of peracetic acid and hydrogen peroxide could be counteracted by the antioxidant system in trout tissues. Correlative analysis between oxidative stress biomarkers and antioxidant defense confirms the pivotal role of SOD and CAT against CIP-induced oxidative stress

Induced resistance to hydrogen peroxide, UV and gamma radiation in bacillus species

International Nuclear Information System (INIS)

Bashandy, A.S.

2005-01-01

The catalase activity produced in four bacillus spp.(bacillus cereus, B. laterosporus, B. pumilus and B. subtilis (Escherichia coli was used for comparison) was measured and the sensitivity of these bacteria to hydrogen peroxide was tested. Bacillus spp. had higher resistance to hydrogen peroxide than E. coil. cultures of bacillus spp . When pretreated with sublethal level of hydrogen peroxide, became relatively resistant to the lethal effects of hydrogen than untreated control cultures. These pretreated cells were also resistant to lethality mediated by UV light and gamma radiation. The obtained results suggest that bacillus spp. Possess inducible defense mechanism (s) against the deleterious effects of oxidants and /or ionizing radiation

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

Science.gov (United States)

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

2005-01-01

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

21 CFR 529.1150 - Hydrogen peroxide.

Science.gov (United States)

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 peroxide...

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

International Nuclear Information System (INIS)

Grunskaya, E.P.; Badovskaya, L.A.; Kaklyugina, T.Ya.; Poskonin, V.V.

2000-01-01

Kinetics of the initial stage of the reaction of furfural with hydrogen peroxide are studied in the presence of Na 2 MoO 4 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 Na 2 MoO 4 . The mechanisms of conversion of furfural in the Na 2 MoO 4 - H 2 O 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 [ru

Different modes of hydrogen peroxide action during seed germination

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Łukasz eWojtyla

2016-02-01

Full Text Available 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

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

OpenAIRE

Haghighat Mamaghani, Alireza; Fatemi, Shohreh; Asgari, Mehrdad

2013-01-01

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

Microscale packed bed reactor for controlled hydrogen peroxide decomposition as a fuel cell oxidant aboard unmanned undersea vehicles

Energy Technology Data Exchange (ETDEWEB)

Lennon, E.; Ocampo, M.; Besser, R.S. [Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, NJ 07030 (United States); Burke, A.A. [Naval Undersea Warfare Center, Newport, RI 02841 (United States)

2010-01-01

The multiphase catalytic decomposition of hydrogen peroxide into water and oxygen is notoriously susceptible to thermal runaway (heat of reaction: -98 kJ mol{sup -1}). The high surface area to volume ratio (S/V) in a microscale packed bed (MPB) reactor (radius 0.5 mm) was investigated for reducing the risk of thermal runaway during hydrogen peroxide decomposition to oxygen intended as a fuel cell oxidant aboard an unmanned undersea vehicle (UUV). A microscale reactor channel with a S/V of {proportional_to}2 x 10{sup 3} m{sup 2} m{sup -3} simulated under convective cooling generated a significant heat rise (T rise {proportional_to} 100 K), whereas a microreactor with a higher S/V ({proportional_to}200 x 10{sup 3} m{sup 2} m{sup -3}) achieved thermal control (T rise < 10 K) over the simulated reaction zone. Although thermal management was successfully accomplished using the higher S/V, experimental conversions of hydrogen peroxide to oxygen (5-18%) measured from the outlet were lower than simulated conversions (38-63%). Simulation assumptions, such as homogeneously dispersed flow and perfect catalyst interaction among other factors, contributed to the discrepancies between the simulated and experimental degrees of peroxide conversion to oxygen. Even though thermal control of the MPB was achieved, this work indicates that mass transfer limitations are a factor in the MPB reactor during a multiphase reaction, like decomposition of hydrogen peroxide to oxygen and water, and suggests means to overcome them even on the microscale level. (author)

Laboratory evaluation of PAH oxidation by magnesium peroxides and iron oxides mixtures as reactive material for groundwater remediation

International Nuclear Information System (INIS)

Valderrama, C.; Gamisans, X.; Cortina, J.L.; Farran, A.; Marti, V.

2005-01-01

Polycyclic Aromatic Hydrocarbons (PAHs) are a class of compounds consisting of two or more fused aromatic rings. They represent the largest group of compounds that are mutagenic, carcinogenic, and teratogenic and are included in the priority pollutants lists. In recent years, increasing attention has been drawn to PAH contamination in aquatic sediments. Biological aerobic degradation was earlier the promoted option to degrade PAH in soils and sediments; however this could be extended for decades. In this direction, addition of oxygen has been proposed as an effective way to speed up their degradation in contaminated soil or groundwater. This objective could be achieved either by adding oxygen releasing compounds or by using an oxygen pump. The latter option is not economically defensible due to the enormous power needed. The use of ex-situ technologies to treat contaminated soils is in general not effective due to the high costs and work efforts demanded to remove big quantities of soil. For that reason, the use of in-situ technologies based on degradation processes has been identified as a suitable approach. These technologies would reduce costs and environmental impacts due to reduction of soil transportations and digging activities. In-situ degradation of recalcitrant contaminants could be achieved by using strong oxidant agents by soil injection or by using permeable treatment wall or zones. Oxidants typically used have been hydrogen peroxide, potassium permanganate and ozone. In situ chemical oxidation using Fenton's reagent (hydrogen peroxide and iron(II) mixtures) has been evaluated for BTEX and poly-aromatic compounds. The successful application of in situ Fenton's reagent chemical oxidation is based on an understanding of oxidant chemistry and the geology, hydrogeology and chemistry of the contaminant site. Choosing the proper conditions requires the determination of 1) the better way to promote the formation of the OH radicals that react with the

Hydrogen sulfide protects HUVECs against hydrogen peroxide induced mitochondrial dysfunction and oxidative stress.

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Ya-Dan Wen

Full Text Available BACKGROUND: Hydrogen sulfide (H₂S has been shown to have cytoprotective effects in models of hypertension, ischemia/reperfusion and Alzheimer's disease. However, little is known about its effects or mechanisms of action in atherosclerosis. Therefore, in the current study we evaluated the pharmacological effects of H₂S on antioxidant defenses and mitochondria protection against hydrogen peroxide (H₂O₂ induced endothelial cells damage. METHODOLOGY AND PRINCIPAL FINDINGS: H₂S, at non-cytotoxic levels, exerts a concentration dependent protective effect in human umbilical vein endothelial cells (HUVECs exposed to H₂O₂. Analysis of ATP synthesis, mitochondrial membrane potential (ΔΨm and cytochrome c release from mitochondria indicated that mitochondrial function was preserved by pretreatment with H₂S. In contrast, in H₂O₂ exposed endothelial cells mitochondria appeared swollen or ruptured. In additional experiments, H₂S was also found to preserve the activities and protein expressions levels of the antioxidants enzymes, superoxide dismutase, catalase, glutathione peroxidase and glutathione-S-transferase in H₂O₂ exposed cells. ROS and lipid peroxidation, as assessed by measuring H₂DCFDA, dihydroethidium (DHE, diphenyl-l-pyrenylphosphine (DPPP and malonaldehyde (MDA levels, were also inhibited by H₂S treatment. Interestingly, in the current model, D, L-propargylglycine (PAG, a selective inhibitor of cystathionine γ-lyase (CSE, abolished the protective effects of H₂S donors. INNOVATION: This study is the first to show that H₂S can inhibit H₂O₂ mediated mitochondrial dysfunction in human endothelial cells by preserving antioxidant defences. SIGNIFICANCE: H₂S may protect against atherosclerosis by preventing H₂O₂ induced injury to endothelial cells. These effects appear to be mediated via the preservation of mitochondrial function and by reducing the deleterious effects of oxidative stress.

Decomposition of hydrogen peroxide on nickel oxide - vanadium pentoxide catalysts and the effect of ionizing radiation on them

International Nuclear Information System (INIS)

Mucka, V.

1984-01-01

Some physico-chemical and catalytic properties of nickel oxide-vanadium pentoxide two-component catalysts were studied over the entire concentration range of the components, using the decomposition of hydrogen peroxide in an aqueous solution as the test reaction. The two oxides were found to affect each other; this was shown by the dependences of the specific surface area, the V 4+ ion concentration, and the catalyst activity on the system composition. At low vanadium pentoxide concentrations (up to 15 mol%) the reaction took place on nickel oxide modified with vanadium pentoxide, whereas in the region of higher vanadium pentoxide concentrations the decomposition of the peroxide was catalyzed primarily in the homogeneous phase by vanadium(V) peroxide ions; in a sample with 30 mol% V 2 O 5 , trivalent vanadium also played a part. With catalysts obtained by mere mechanical mixing of the two oxides, a modified activity was observed in the region of high excess of nickel oxide. The activity of catalyst, particularly pure nickel oxide, was increased by its partial reduction and decreased by its exposure to gamma radiation if the dose was higher than 10 5 Gy. The effects observed are interpreted in terms of the concept of bivalent catalytic centres. (author)

Kinetics of Platinum-Catalyzed Decomposition of Hydrogen Peroxide

Science.gov (United States)

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

2003-07-01

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

Degradation of the ethyl glucuronide content in hair by hydrogen peroxide and a non-destructive assay for oxidative hair treatment using infra-red spectroscopy.

Science.gov (United States)

Ammann, Dominic; Becker, Roland; Kohl, Anka; Hänisch, Jessica; Nehls, Irene

2014-11-01

The assessment of quantification results of the alcohol abuse marker ethyl glucuronide (EtG) in hair in comparison to the cut-off values for the drinking behavior may be complicated by cosmetic hair bleaching. Thus, the impact of increasing exposure to hydrogen peroxide on the EtG content of hair was investigated. Simultaneously, the change of absorbance in the range of 1000-1100 cm(-1) indicative for the oxidation of cystine was investigated non-destructively by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) using pulverized portions of the respective hair samples. Hair samples treated with hydrogen peroxide consistently displayed a significantly increased absorbance at 1040 cm(-1) associated with the formation of cysteic acid. The EtG content decreased significantly if the hair was treated with alkaline hydrogen peroxide as during cosmetic bleaching. It could be shown that ATR-FTIR is capable of detecting an exposure to hydrogen peroxide when still no brightening was visible and already before the EtG content deteriorated significantly. Thus, hair samples suspected of having been exposed to oxidative treatment may be checked non-destructively by a readily available technique. This assay is also possible retrospectively after EtG extraction and using archived samples. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Effect of hydrogen and propylene on the hydrogen peroxide decomposition over Pt, PtO and Au catalysts

NARCIS (Netherlands)

Kertalli, E.; Schouten, J.C.; Nijhuis, T.A.

2017-01-01

The decomposition of hydrogen peroxide (H2O2) on Pt, PtO and Au catalysts has been investigated in the presence of nitrogen, propylene and hydrogen. H2O2 formation on the catalyst is known to be a key intermediate step for the direct synthesis of propylene oxide (PO) from hydrogen, propylene and

Microwave-Accelerated Iodination of Some Aromatic Amines, Using Urea-Hydrogen Peroxide Addition Compound (UHP as the Oxidant

Directory of Open Access Journals (Sweden)

Lech Skulski

2002-12-01

Full Text Available A fast and simple method for the oxidative iodination of some aromatic amines, under microwave irradiation, is reported, using diiodine and the the strongly Hbonded urea-hydrogen peroxide addition compound (H2NCONH2···H2O2, UHP as the oxidant. The reactions were carried out in boiling CHCl3 under a reflux condenser to afford, within 10 minutes, the purified monoiodinated products in 40-80% yields.

Enzyme catalytic resonance scattering spectral detection of trace hydrogen peroxide using guaiacol as substrate

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Shiwen Huang

2011-08-01

Full Text Available Hydrogen peroxide oxidized guaiacol to form tetramer particles that exhibited a strong resonance scattering (RS peak at 530 nm in the presence of horseradish peroxidase (HRP in citric acid-Na2HPO4 buffer solution of pH 4.4. The RS peak increased when the concentration of hydrogen peroxide increased. The increased RS intensity (ΔI530 nm was linear to the hydrogen peroxide concentration in the range of 0.55-27.6 μM, with a linear regression equation of ΔI530 nm = 17.1C + 1.6, a relative coefficient of 0.9996 and a detection limit of 0.03 μM H2O2. This proposed method was applied to detect hydrogen peroxide in rain water, with sensitivity, selectivity, rapidity, and recovery of 98.0-104 %.

Kinetic Studies on Enzyme-Catalyzed Reactions: Oxidation of Glucose, Decomposition of Hydrogen Peroxide and Their Combination

Science.gov (United States)

Tao, Zhimin; Raffel, Ryan A.; Souid, Abdul-Kader; Goodisman, Jerry

2009-01-01

The kinetics of the glucose oxidase-catalyzed reaction of glucose with O2, which produces gluconic acid and hydrogen peroxide, and the catalase-assisted breakdown of hydrogen peroxide to generate oxygen, have been measured via the rate of O2 depletion or production. The O2 concentrations in air-saturated phosphate-buffered salt solutions were monitored by measuring the decay of phosphorescence from a Pd phosphor in solution; the decay rate was obtained by fitting the tail of the phosphorescence intensity profile to an exponential. For glucose oxidation in the presence of glucose oxidase, the rate constant determined for the rate-limiting step was k = (3.0 ± 0.7) ×104 M−1s−1 at 37°C. For catalase-catalyzed H2O2 breakdown, the reaction order in [H2O2] was somewhat greater than unity at 37°C and well above unity at 25°C, suggesting different temperature dependences of the rate constants for various steps in the reaction. The two reactions were combined in a single experiment: addition of glucose oxidase to glucose-rich cell-free media caused a rapid drop in [O2], and subsequent addition of catalase caused [O2] to rise and then decrease to zero. The best fit of [O2] to a kinetic model is obtained with the rate constants for glucose oxidation and peroxide decomposition equal to 0.116 s−1 and 0.090 s−1 respectively. Cellular respiration in the presence of glucose was found to be three times as rapid as that in glucose-deprived cells. Added NaCN inhibited O2 consumption completely, confirming that oxidation occurred in the cellular mitochondrial respiratory chain. PMID:19348778

Urea- Hydrogen Peroxide (UHP Oxidation of Thiols to the Corresponding Disulfides Promoted by Maleic Anhydride as Mediator

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M. H. Habibi

2005-10-01

Full Text Available Urea-hydrogen peroxide (UHP was used in the presence of maleic anhydride as mediator in a simple and convenient method for the oxidation in high yield of some thiols to the corresponding disulfides. Peroxymaleic acid formed in situ from the reaction of UHP with maleic anhydride has a key role in this oxidation. Performance of the reaction in various solvents showed that methanol was the solvent of choice at 0 oC. The products were isolated by simple filtration on silica gel.

Determination of hydrogen peroxide in water by chemiluminescence detection, (1). Flow injection type hydrogen peroxide detection system

International Nuclear Information System (INIS)

Yamashiro, Naoya; Uchida, Shunsuke; Satoh, Yoshiyuki; Morishima, Yusuke; Yokoyama, Hiroaki; Satoh, Tomonori; Sugama, Junichi; Yamada, Rie

2004-01-01

A flow injection type hydrogen peroxide detection system with a sub-ppb detection limit has been developed to determine hydrogen peroxide concentration in water sampled from a high temperature, high pressure hydrogen peroxide water loop. The hydrogen peroxide detector is based on luminol chemiluminescence spectroscopy. A small amount of sample water (20 μl) is mixed with a reagent mixture, an aqueous solution of luminol and Co 2+ catalyst, in a mixing cell which is installed just upstream from the detection cell. The optimum values for pH and the concentrations of luminol and Co 2+ ion have been determined to ensure a lower detectable limit and a higher reproducibility. The photocurrent detected by the detection system is expressed by a linear function of the hydrogen peroxide concentration in the region of lower concentration ([H 2 O 2 ] 2 O 2 ] in the region of higher concentration ([H 2 O 2 ] > 10 ppb). The luminous intensity of luminol chemiluminescence is the highest when pH of the reagent mixture is 11.0. Optimization of the major parameters gives the lowest detectable limit of 0.3 ppb. (author)

7 CFR 58.431 - Hydrogen peroxide.

Science.gov (United States)

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 U.S...

Coupling mechanism between wear and oxidation processes of 304 stainless steel in hydrogen peroxide environments.

Science.gov (United States)

Dong, Conglin; Yuan, Chengqing; Bai, Xiuqin; Li, Jian; Qin, Honglin; Yan, Xinping

2017-05-24

Stainless steel is widely used in strongly oxidizing hydrogen peroxide (H 2 O 2 ) environments. It is crucial to study its wear behaviour and failure mode. The tribological properties and oxidation of 304 stainless steel were investigated using a MMW-1 tribo-tester with a three-electrode setup in H 2 O 2 solutions with different concentrations. Corrosion current densities (CCDs), coefficients of frictions (COFs), wear mass losses, wear surface topographies, and metal oxide films were analysed and compared. The results show that the wear process and oxidation process interacted significantly with each other. Increasing the concentration of H 2 O 2 or the oxidation time was useful to form a layer of integrated, homogeneous, compact and thick metal oxide film. The dense metal oxide films with higher mechanical strengths improved the wear process and also reduced the oxidation reaction. The wear process removed the metal oxide films to increase the oxidation reaction. Theoretical data is provided for the rational design and application of friction pairs in oxidation corrosion conditions.

Arylboronate ester based diazeniumdiolates (BORO/NO), a class of hydrogen peroxide inducible nitric oxide (NO) donors.

Science.gov (United States)

Dharmaraja, Allimuthu T; Ravikumar, Govindan; Chakrapani, Harinath

2014-05-16

Here, we report the design, synthesis, and evaluation of arylboronate ester based diazeniumdiolates (BORO/NO), a class of nitric oxide (NO) donors activated by hydrogen peroxide (H2O2), a reactive oxygen species (ROS), to generate NO. We provide evidence for the NO donors' ability to permeate bacteria to produce NO when exposed to H2O2 supporting possible applications for BORO/NO to study molecular mechanisms of NO generation in response to elevated ROS.

Hydrogen peroxide biosensor based on titanium oxide

Science.gov (United States)

Halim, Nur Hamidah Abdul; Heng, Lee Yook; Hashim, Uda

2015-09-01

In this work, a biosensor utilizing modified titania, TiO2 particles using aminopropyl-triethoxy-silane, (APTS) for developing hydrogen peroxide biosensor is presented. The surface of Ti-APTS particles is used as a support for hemoglobin immobilization via covalent bonding. The performance of the biosensor is determined by differential pulse voltammetry. The linear response was observed at the reduction current of redox mediator probe [FeCN6]3-/4- at potential between 0.22 V to 0.24 V. The preliminary result for electrochemistry study on this modified electrode is reported. The preliminary linear range is obtained from 1×10-2 M to 1×10-8 M.

Wind-Eroded Silicate as a Source of Hydrogen Peroxide on Mars

Science.gov (United States)

Bak, E. N.; Merrison, J. P.; Jensen, S. K.; Nørnberg, P.; Finster, K.

2014-07-01

Laboratory simulations show that wind-eroded silicate can be a source of hydrogen peroxide. The ubiquitous, fine-grained silicate dust might thus explain the oxidizing properties of the martian soil and affect the preservation of organic compounds.

Electron paramagnetic resonance study of lipid and protein membrane components of erythrocytes oxidized with hydrogen peroxide

Energy Technology Data Exchange (ETDEWEB)

Mendanha, S.A.; Anjos, J.L.V.; Silva, A.H.M.; Alonso, A. [Instituto de Física, Universidade Federal de Goiás, Goiânia, GO (Brazil)

2012-04-05

Electron paramagnetic resonance (EPR) spectroscopy of spin labels was used to monitor membrane dynamic changes in erythrocytes subjected to oxidative stress with hydrogen peroxide (H{sub 2}O{sub 2}). The lipid spin label, 5-doxyl stearic acid, responded to dramatic reductions in membrane fluidity, which was correlated with increases in the protein content of the membrane. Membrane rigidity, associated with the binding of hemoglobin (Hb) to the erythrocyte membrane, was also indicated by a spin-labeled maleimide, 5-MSL, covalently bound to the sulfhydryl groups of membrane proteins. At 2% hematocrit, these alterations in membrane occurred at very low concentrations of H{sub 2}O{sub 2} (50 µM) after only 5 min of incubation at 37°C in azide phosphate buffer, pH 7.4. Lipid peroxidation, suggested by oxidative hemolysis and malondialdehyde formation, started at 300 µM H{sub 2}O{sub 2} (for incubation of 3 h), which is a concentration about six times higher than those detected with the probes. Ascorbic acid and α-tocopherol protected the membrane against lipoperoxidation, but did not prevent the binding of proteins to the erythrocyte membrane. Moreover, the antioxidant (+)-catechin, which also failed to prevent the cross-linking of cytoskeletal proteins with Hb, was very effective in protecting erythrocyte ghosts from lipid peroxidation induced by the Fenton reaction. This study also showed that EPR spectroscopy can be useful to assess the molecular dynamics of red blood cell membranes in both the lipid and protein domains and examine oxidation processes in a system that is so vulnerable to oxidation.

Catalytic oxidative desulfurization of diesel utilizing hydrogen peroxide and functionalized-activated carbon in a biphasic diesel-acetonitrile system

Energy Technology Data Exchange (ETDEWEB)

Haw, Kok-Giap; Bakar, Wan Azelee Wan Abu; Ali, Rusmidah; Chong, Jiunn-Fat [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia); Kadir, Abdul Aziz Abdul [Department of Petroleum Engineering, Faculty of Chemical and Natural Resources Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia)

2010-09-15

This paper presents the development of granular functionalized-activated carbon as catalysts in the catalytic oxidative desulfurization (Cat-ODS) of commercial Malaysian diesel using hydrogen peroxide as oxidant. Granular functionalized-activated carbon was prepared from oil palm shell using phosphoric acid activation method and carbonized at 500 C and 700 C for 1 h. The activated carbons were characterized using various analytical techniques to study the chemistry underlying the preparation and calcination treatment. Nitrogen adsorption/desorption isotherms exhibited the characteristic of microporous structure with some contribution of mesopore property. The Fourier Transform Infrared Spectroscopy results showed that higher activation temperature leads to fewer surface functional groups due to thermal decomposition. Micrograph from Field Emission Scanning Electron Microscope showed that activation at 700 C creates orderly and well developed pores. Furthermore, X-ray Diffraction patterns revealed that pyrolysis has converted crystalline cellulose structure of oil palm shell to amorphous carbon structure. The influence of the reaction temperature, the oxidation duration, the solvent, and the oxidant/sulfur molar ratio were examined. The rates of the catalytic oxidative desulfurization reaction were found to increase with the temperature, and H{sub 2}O{sub 2}/S molar ratio. Under the best operating condition for the catalytic oxidative desulfurization: temperature 50 C, atmospheric pressure, 0.5 g activated carbon, 3 mol ratio of hydrogen peroxide to sulfur, 2 mol ratio of acetic acid to sulfur, 3 oxidation cycles with 1 h for each cycle using acetonitrile as extraction solvent, the sulfur content in diesel was reduced from 2189 ppm to 190 ppm with 91.3% of total sulfur removed. (author)

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

Science.gov (United States)

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

2015-10-01

Whey protein is a highly functional food ingredient used in a wide variety of applications. A large portion of fluid whey produced in the United States is derived from Cheddar cheese manufacture and contains annatto (norbixin), and therefore must be bleached. The objective of this study was to compare sensory and functionality differences between whey protein isolate (WPI) bleached by benzoyl peroxide (BP) or hydrogen peroxide (HP). HP and BP bleached WPI and unbleached controls were manufactured in triplicate. Descriptive sensory analysis and gas chromatography-mass spectrometry were conducted to determine flavor differences between treatments. Functionality differences were evaluated by measurement of foam stability, protein solubility, SDS-PAGE, and effect of NaCl concentration on gelation relative to an unbleached control. HP bleached WPI had higher concentrations of lipid oxidation and sulfur containing volatile compounds than both BP and unbleached WPI (P protein loss at pH 4.6 of WPI decreased by bleaching with either hydrogen peroxide or benzoyl peroxide (P whey with either BP or HP resulted in protein degradation, which likely contributed to functionality differences. These results demonstrate that bleaching has flavor effects as well as effects on many of the functionality characteristics of whey proteins. Whey protein isolate (WPI) is often used for its functional properties, but the effect of oxidative bleaching chemicals on the functional properties of WPI is not known. This study identifies the effects of hydrogen peroxide and benzoyl peroxide on functional and flavor characteristics of WPI bleached by hydrogen and benzoyl peroxide and provides insights for the product applications which may benefit from bleaching. © 2015 Institute of Food Technologists®

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

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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

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

International Nuclear Information System (INIS)

Yusof, Muhammad Jefri Mohd; Jamaluddin, Naharullah; Abdullah, Ibrahim; Yusoff, Siti Fairus M.

2015-01-01

Liquid natural rubber (LNR) with molecular weight of lower than 10 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)

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

Science.gov (United States)

Yusof, Muhammad Jefri Mohd; Jamaluddin, Naharullah; Abdullah, Ibrahim; Yusoff, Siti Fairus M.

2015-09-01

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).

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

Energy Technology Data Exchange (ETDEWEB)

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)

Modification of Coal Char-loaded TiO2 by Sulfonation and Alkylsilylation to Enhance Catalytic Activity in Styrene Oxidation with Hydrogen Peroxide as Oxidant

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Mukhamad Nurhadi

2017-04-01

Full Text Available The modified coal char from low-rank coal by sulfonation, titanium impregnation and followed by alkyl silylation possesses high catalytic activity in styrene oxidation. The surface of coal char was undergone several steps as such: modification using concentrated sulfuric acid in the sulfonation process, impregnation of 500 mmol titanium(IV isopropoxide and followed by alkyl silylation of n-octadecyltriclorosilane (OTS. The catalysts were characterized by X-ray diffraction (XRD, IR spectroscopy, nitrogen adsorption, and hydrophobicity. The catalytic activity of the catalysts has been examined in the liquid phase styrene oxidation by using aqueous hydrogen peroxide as oxidant. The catalytic study showed the alkyl silylation could enhance the catalytic activity of Ti-SO3H/CC-600(2.0. High catalytic activity and reusability of the o-Ti-SO3H/CC-600(2.0 were related to the modification of local environment of titanium active sites and the enhancement the hydrophobicity of catalyst particle by alkyl silylation. Copyright © 2017 BCREC GROUP. All rights reserved Received: 24th May 2016; Revised: 11st October 2016; Accepted: 18th October 2016 How to Cite: Nurhadi, M. (2017. Modification of Coal Char-loaded TiO2 by Sulfonation and Alkylsilylation to Enhance Catalytic Activity in Styrene Oxidation with Hydrogen Peroxide as Oxidant. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (1: 55-61 (doi:10.9767/bcrec.12.1.501.55-61 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.12.1.501.55-61

Hydrogen peroxide treatment of TCE contaminated soil

International Nuclear Information System (INIS)

Hurst, D.H.; Robinson, K.G.; Siegrist, R.L.

1993-01-01

Solvent contaminated soils are ubiquitous in the industrial world and represent a significant environmental hazard due to their persistence and potentially negative impacts on human health and the environment. Environmental regulations favor treatment of soils with options which reduce the volume and toxicity of contaminants in place. One such treatment option is the in-situ application of hydrogen peroxide to soils contaminated with chlorinated solvents such as trichloroethylene (TCE). This study investigated hydrogen peroxide mass loading rates on removal of TCE from soils of varying organic matter content. Batch experiments conducted on contaminated loam samples using GC headspace analysis showed up to 80% TCE removal upon peroxide treatment. Column experiments conducted on sandy loam soils with high organic matter content showed only 25% TCE removal, even at hydrogen peroxide additions of 25 g peroxide per kg soil

Hydrogen peroxide probes directed to different cellular compartments.

OpenAIRE

Mikalai Malinouski; You Zhou; Vsevolod V Belousov; Dolph L Hatfield; Vadim N Gladyshev

2011-01-01

Background Controlled generation and removal of hydrogen peroxide play important roles in cellular redox homeostasis and signaling. We used a hydrogen peroxide biosensor HyPer, targeted to different compartments, to examine these processes in mammalian cells. Principal Findings Reversible responses were observed to various redox perturbations and signaling events. HyPer expressed in HEK 293 cells was found to sense low micromolar levels of hydrogen peroxide. When targeted to various cellular ...

Determination of cholesterol oxides in anchovies (Engraulis encrasicolus treated with a commercial mixture of citric acid, trisodium acid and hydrogen peroxide

Directory of Open Access Journals (Sweden)

Aniello Anastasio

2013-02-01

Full Text Available A new additive formulation containing hydrogen peroxide, citric acid and trisodium acid is illegally used in fishery products due its whitening and antioxidant features. Aim of this study was to evaluate the possible presence of COPs and their role as markers of illegal treatment in anchovies (Engraulis encrasicolus stored at different temperatures. Sensory analysis was also performed by the specific QIM test. The quantitative determinations (% of cholesterol oxides (COPs showed changing amounts during storage. Not always The COPs measured in the treated samples were significantly higher than control samples. Considering the volatility of hydrogen peroxide and the poor repeatability of COPs analyses, as shown in the present study, it is crucial to intensify the control by the Authorities.

Direct synthesis of hydrogen peroxide in a microreactor

NARCIS (Netherlands)

Paunovic, V.; Schouten, J.C.; Nijhuis, T.A.

2014-01-01

The direct synthesis of hydrogen peroxide in a microreactor is a safe and efficient process. Conventionally, hydrogen peroxide is produced using the anthraquinone autooxidation process, which is rather complex and can only be performed cost-effectively on a large scale. As a result, hydrogen

Reinvestigation of the Henry's law constant for hydrogen peroxide with temperature and acidity variation.

Science.gov (United States)

Huang, Daoming; Chen, Zhongming

2010-01-01

Hydrogen peroxide is not only an important oxidant in itself; it also serves as both sink and temporary reservoir for other important oxidants including HOx (OH and HO2) radicals and O3 in the atmosphere. Its partitioning between gas and aqueous phases in the atmosphere, usually described by its Henry's law constant (K(H)), significantly influences its role in atmospheric processes. Large discrepancies between the K(H) values reported in previous work, however, have created uncertainty for atmospheric modelers. Based on our newly developed online instrumentation, we have re-determined the temperature and acidity dependence of K(H) for hydrogen peroxide at an air pressure of (0.960 +/- 0.013) atm (1 atm = 1.01325 x 10(5) Pa). The results indicated that the temperature dependence of K(H) for hydrogen peroxide fits to the Van't Hoff equation form, expressed as lnK(H) = a/T - b, and a = -deltaH/R, where K(H) is in M/atm (M is mol/L), T is in degrees Kelvin, R is the ideal gas constant, and deltaH is the standard heat of solution. For acidity dependence, results demonstrated that the K(H) value of hydrogen peroxide appeared to have no obvious dependence on decreasing pH level (from pH 7 to pH 1). Combining the dependence of both temperature and acidity, the obtained a and b were 7024 +/- 138 and 11.97 +/- 0.48, respectively, deltaH was (58.40 +/- 1.15) kJ/(K x mol), and the uncertainties represent sigma. Our determined K(H) values for hydrogen peroxide will therefore be of great use in atmospheric models.

Amperometric biosensor for the detection of hydrogen peroxide using catalase modified electrodes in polyacrylamide.

Science.gov (United States)

Varma, Shailly; Mattiasson, Bo

2005-09-23

A simple biosensor for the detection of hydrogen peroxide in organic solvents has been developed and coupled to a flow injection analysis (FIA) system. Catalase was entrapped in polyacrylamide gel and placed on the surface of platinum (working electrode) fixed in a Teflon holder with Ag-wire (auxiliary electrode), followed by addition of filter paper soaked in KCl. The entrapped catalase gel was held on the electrode using membranes. The effects of cellulose and polytetrafluroethylene (PTFE) membranes on the electrode response towards hydrogen peroxide have been studied. The modified electrode has been used to study the detection of hydrogen peroxide in solvents like water, dimethyl sulfoxide (DMSO), and 1,4-dioxane using amperometric techniques like cyclic voltammetry (CV) and FIA. The CV of modified catalase electrode showed a broad oxidation peak at -150 mV and a clear reduction peak at -212 mV in the presence of hydrogen peroxide. Comparison of CV with hydrogen peroxide in various solvents has been carried out. The electrode showed an irreversible kinetics with DMSO as the solvent. A flow cell has been designed in order to carry on FIA studies to obtain calibration plots for hydrogen peroxide with the modified electrode. The calibration plots in several solvents such as water, dimethyl sulfoxide, 1,4-dioxane have been obtained. The throughput of the enzyme electrode was 10 injections per hour. Due to the presence of membrane the response time of the electrode is concentration dependent.

Engineering bacterial motility towards hydrogen-peroxide.

Science.gov (United States)

Virgile, Chelsea; Hauk, Pricila; Wu, Hsuan-Chen; Shang, Wu; Tsao, Chen-Yu; Payne, Gregory F; Bentley, William E

2018-01-01

Synthetic biologists construct innovative genetic/biological systems to treat environmental, energy, and health problems. Many systems employ rewired cells for non-native product synthesis, while a few have employed the rewired cells as 'smart' devices with programmable function. Building on the latter, we developed a genetic construct to control and direct bacterial motility towards hydrogen peroxide, one of the body's immune response signaling molecules. A motivation for this work is the creation of cells that can target and autonomously treat disease, the latter signaled by hydrogen peroxide release. Bacteria naturally move towards a variety of molecular cues (e.g., nutrients) in the process of chemotaxis. In this work, we engineered bacteria to recognize and move towards hydrogen peroxide, a non-native chemoattractant and potential toxin. Our system exploits oxyRS, the native oxidative stress regulon of E. coli. We first demonstrated H2O2-mediated upregulation motility regulator, CheZ. Using transwell assays, we showed a two-fold increase in net motility towards H2O2. Then, using a 2D cell tracking system, we quantified bacterial motility descriptors including velocity, % running (of tumble/run motions), and a dynamic net directionality towards the molecular cue. In CheZ mutants, we found that increased H2O2 concentration (0-200 μM) and induction time resulted in increased running speeds, ultimately reaching the native E. coli wild-type speed of ~22 μm/s with a ~45-65% ratio of running to tumbling. Finally, using a microfluidic device with stable H2O2 gradients, we characterized responses and the potential for "programmed" directionality towards H2O2 in quiescent fluids. Overall, the synthetic biology framework and tracking analysis in this work will provide a framework for investigating controlled motility of E. coli and other 'smart' probiotics for signal-directed treatment.

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

Directory of Open Access Journals (Sweden)

M Goldani

2012-12-01

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

Dibenzazepin hydrochloride as a new spectrophotometric reagent for determination of hydrogen peroxide in plant extracts.

Science.gov (United States)

Nagaraja, P; Prakash, J S; Asha, S C; Bhaskara, B L; Kumar, S Anil

2012-10-01

A rapid, simple, accurate, and sensitive visible spectrophotometric method for the determination of trace amounts of hydrogen peroxide in acidic buffer medium is reported. The proposed method is based on the oxidative coupling of Ampyrone with dibenzazepin hydrochloride by hydrogen peroxide in the buffer medium of pH 4.0 which is catalyzed by ferrous iron. The blue-colored product formed with maximum absorption at 620 nm was found to be stable for 2 h. Beer's law is obeyed for hydrogen peroxide concentration in the range of 0.03-0.42 μg ml(-1). The optimum reaction conditions and other important optical parameters are reported. The molar absorptive and Sandell's sensitivity are found to be 5.89 × 10(4) mol(-1) cm(-1) and 0.57 g/cm(2), respectively. The interference due to diverse ions and complexing agents was studied. The method is successfully applied to the determination of hydrogen peroxide in green plants satisfactorily.

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

Science.gov (United States)

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

2015-03-25

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

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

Science.gov (United States)

Gogoi, Satyabrat; Karak, Niranjan

2017-10-01

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

Hydrogen Peroxide- and Nitric Oxide-mediated Disease Control of Bacterial Wilt in Tomato Plants

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Jeum Kyu Hong

2013-12-01

Full Text Available Reactive oxygen species (ROS generation in tomato plants by Ralstonia solanacearum infection and the role of hydrogen peroxide (H₂O₂ and nitric oxide in tomato bacterial wilt control were demonstrated. During disease development of tomato bacterial wilt, accumulation of superoxide anion (O₂− and H₂O₂ was observed and lipid peroxidation also occurred in the tomato leaf tissues. High doses of H₂O₂and sodium nitroprusside (SNP nitric oxide donor showed phytotoxicity to detached tomato leaves 1 day after petiole feeding showing reduced fresh weight. Both H₂O₂and SNP have in vitro antibacterial activities against R. solanacearum in a dose-dependent manner, as well as plant protection in detached tomato leaves against bacterial wilt by 10⁶ and 10⁷ cfu/ml of R. solanacearum. H₂O₂- and SNP-mediated protection was also evaluated in pots using soil-drench treatment with the bacterial inoculation, and relative ‘area under the disease progressive curve (AUDPC’ was calculated to compare disease protection by H₂O₂ and/or SNP with untreated control. Neither H₂O₂ nor SNP protect the tomato seedlings from the bacterial wilt, but H₂O₂+ SNP mixture significantly decreased disease severity with reduced relative AUDPC. These results suggest that H₂O₂ and SNP could be used together to control bacterial wilt in tomato plants as bactericidal agents.

Layer-by-layer immobilized catalase on electrospun nanofibrous mats protects against oxidative stress induced by hydrogen peroxide.

Science.gov (United States)

Huang, Rong; Deng, Hongbing; Cai, Tongjian; Zhan, Yingfei; Wang, Xiankai; Chen, Xuanxuan; Ji, Ailing; Lil, Xueyong

2014-07-01

Catalase, a kind of redox enzyme and generally recognized as an efficient agent for protecting cells against hydrogen peroxide (H2O2)-induced cytotoxicity. The immobilization of catalase was accomplished by depositing the positively charged chitosan and the negatively charged catalase on electrospun cellulose nanofibrous mats through electrospining and layer-by-layer (LBL) techniques. The morphology obtained from Field emission scanning electron microscopy (FE-SEM) indicated that more orderly arranged three-dimension (3D) structure and roughness formed with increasing the number of coating bilayers. Besides, the enzyme-immobilized nanofibrous mats were found with high enzyme loading and activity, moreover, X-ray photoelectron spectroscopy (XPS) results further demonstrated the successful immobilization of chitosan and catalase on cellulose nanofibers support. Furthermore, we evaluated the cytotoxicity induced by hydrogen peroxide in the Human umbilical vascular endothelial cells with or without pretreatment of nanofibrous mats by MTT assay, LDH activity and Flow cytometric evaluation, and confirmed the pronounced hydrogen peroxide-induced toxicity, but pretreatment of immobilized catalase reduced the cytotoxicity and protected cells against hydrogen peroxide-induced cytotoxic effects which were further demonstrated by scanning electron microscopy (SEM) and Transmission Electron Microscopy (TEM) images. The data pointed toward a role of catalase-immobilized nanofibrous mats in protecting cells against hydrogen peroxide-induced cellular damage and their potential application in biomedical field.

Flow injection determination of hydrogen peroxide using catalytic effect of cobalt(II) ion on a dye formation reaction.

Science.gov (United States)

Kurihara, Makoto; Muramatsu, Miyuki; Yamada, Mari; Kitamura, Naoya

2012-07-15

A novel flow injection photometric method was developed for the determination of hydrogen peroxide in rainwater. This method is based on a cobalt(II)-catalyzed oxidative coupling of 3-methyl-2-benzothiazolinone hydrazone (MBTH) with N-ethyl-N-(2-hydroxy-3-sulfopropyl)-3,5-dimethoxyaniline (DAOS) as a modified Trinder's reagent to produce intensely colored dye (λ(max)=530nm) in the presence of hydrogen peroxide at pH 8.4. In this method, 1,2-dihydroxy-3,5-benzenedisulfonic acid (Tiron) acted as an activator for the cobalt(II)-catalyzed reaction and effectively increased the peak height for hydrogen peroxide. The linear calibration graphs were obtained in the hydrogen peroxide concentration range 5×10(-8) to 2.2×10(-6)mol dm(-3) at a sampling rate of 20h(-1). The relative standard deviations for ten determinations of 2.2×10(-6) and 2×10(-7)mol dm(-3) hydrogen peroxide were 1.1% and 3.7%, respectively. The proposed method was successfully applied to the determination of hydrogen peroxide in rainwater samples and the analytical results agreed fairly well with the results obtained by different two reference methods; peroxidase method and hydrogen peroxide electrode method. Copyright © 2012 Elsevier B.V. All rights reserved.

Bacillus pumilus KatX2 confers enhanced hydrogen peroxide resistance to a Bacillus subtilis PkatA::katX2 mutant strain.

Science.gov (United States)

Handtke, Stefan; Albrecht, Dirk; Zühlke, Daniela; Otto, Andreas; Becher, Dörte; Schweder, Thomas; Riedel, Kathrin; Hecker, Michael; Voigt, Birgit

2017-04-26

Bacillus pumilus cells exhibit a significantly higher resistance to hydrogen peroxide compared to closely related Bacilli like Bacillus subtilis. In this study we analyzed features of the catalase KatX2 of B. pumilus as one of the most important parts of the cellular response to hydrogen peroxide. KatX2, the vegetative catalase expressed in B. pumilus, was compared to the vegetative catalase KatA of B. subtilis. Data of our study demonstrate that B. pumilus can degrade toxic concentrations of hydrogen peroxide faster than B. subtilis. By replacing B. subtilis katA gene by katX2 we could significantly enhance its resistance to H 2 O 2 and its potential to eliminate this toxic compound. Mutant cells showed a 1.5- to 2-fold higher survival to toxic concentrations of hydrogen peroxide compared to wild type cells. Furthermore, we found reversible but also irreversible oxidations of the KatX2 protein which, in contrast to KatA, contains several cysteine residues. Our study indicates that the catalase KatX2 plays a major role in the increased resistance of B. pumilus to oxidative stress caused by hydrogen peroxide. Resistance to hydrogen peroxide of other Bacilli can be enhanced by exchanging the native catalase in the cells with katX2.

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

Science.gov (United States)

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

2017-10-01

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

Pistacia lentiscus fruit oil reduces oxidative stress in human skin explants caused by hydrogen peroxide.

Science.gov (United States)

Ben Khedir, S; Moalla, D; Jardak, N; Mzid, M; Sahnoun, Z; Rebai, T

2016-10-01

We investigated the efficacy of Pistacia lentiscus fruit oil (PLFO) for protecting human skin from damage due to oxidative stress. PLFO contains natural antioxidants including polyphenols, sterols and tocopherols. We compared the antioxidant potential of PLFO with extra virgin olive oil (EVOO). Explants of healthy adult human skin were grown in culture with either PLFO or EVOO before adding hydrogen peroxide (H 2 O 2 ). We also used cultured skin explants to investigate the effects of PLFO on lipid oxidation and depletion of endogenous antioxidant defense enzymes including glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT) one day after 2 h exposure to H 2 O 2 . We found that PLFO scavenged radicals and protected skin against oxidative injury. PLFO exhibited greater antioxidant and free radical scavenging activity than EVOO. Skin explants treated with PLFO inhibited H 2 O 2 induced MDA formation by inhibition of lipid oxidation. In addition, the oil inhibited H 2 O 2 induced depletion of antioxidant defense enzymes including GPx, SOD and CAT. We found that treatment with PLFO repaired skin damage owing to its antioxidant properties.

Origin of the different behavior of some platinum decorated nanocarbons towards the electrochemical oxidation of hydrogen peroxide

International Nuclear Information System (INIS)

Malara, A.; Leonardi, S.G.; Bonavita, A.; Fazio, E.; Stelitano, S.; Neri, G.; Neri, F.; Santangelo, S.

2016-01-01

The electrochemical behavior of different platinum-decorated nanocarbons (Pt@C) towards the oxidation of hydrogen peroxide (H_2O_2) was investigated. Three different types of nanocarbons were considered: i) carbon black, ii) dahlia-like carbon nanohorns and iii) carbon nanotubes, which included both commercial (single-wall and multi-wall) and laboratory prepared (multi-wall) samples. Shape and size distribution of the platinum nanoparticles and morphology of the nanocarbons were analyzed by transmission electron microscopy. Their nanostructure was investigated by micro-Raman spectroscopy, while elemental composition of the samples and chemical bonding states were studied by X-ray photoelectron spectroscopy. Electrochemical behavior towards H_2O_2 oxidation was evaluated by means of cyclic voltammetry modifying the working screen-printed carbon electrode surface with the prepared Pt@C nanocomposites. Data obtained suggest that the size and dispersion of the Pt nanoparticles play a key role in increasing the sensitivity towards H_2O_2 detection. Thanks to the presence of smaller and more dispersed platinum particles and of a greater amount of platinum hydroxide, acting as intermediary in the H_2O_2 oxidation process, Pt@dahlia-like carbon nanohorns result to be the most promising platform for the development of H_2O_2 electrochemical sensors. - Highlights: • Different nanocarbons are decorated with Pt nanoparticles by wet impregnation method. • Pt@C-based hybrids are tested as active materials for sensing of hydrogen peroxide. • Sensor based on Pt@dahlia-like carbon nanohorns is the most performing device. • The origin of the different electrochemical behaviour is investigated. • Pt@C sensing performances are correlated with their structural and surface properties.

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

International Nuclear Information System (INIS)

Collivignarelli, C.; Sorlini, S.; Riganti, V.

2001-01-01

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 [it

Kinetics and mechanism of the oxidation of alkenes and silanes by hydrogen peroxide catalyzed by methylrhenium trioxide (MTO) and a novel application of electrospray mass spectrometry to study the hydrolysis of MTO

Energy Technology Data Exchange (ETDEWEB)

Tan, Haisong [Iowa State Univ., Ames, IA (United States)

1999-11-08

Conjugated dienes were oxidized by hydrogen peroxide with methylrhenium trioxide (MTO) as catalyst. Methylrhenium bis-peroxide was the major reactive catalyst present. Hydroxyalkenes and trisubstituted silane were also tested. Mechanisms for each of these reactions are presented.

A hydrogen peroxide sensor for exhaled breath measurement

NARCIS (Netherlands)

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

2004-01-01

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

A hydrogen peroxide sensor for exhaled breath measurement

NARCIS (Netherlands)

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

2005-01-01

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

Ecofriendly laccase-hydrogen peroxide/ultrasound-assisted bleaching of linen fabrics and its influence on dyeing efficiency.

Science.gov (United States)

Abou-Okeil, A; El-Shafie, A; El Zawahry, M M

2010-02-01

This study evaluates the bleaching efficiency of enzymatically scoured linen fabrics using a combined laccase-hydrogen peroxide bleaching process with and without ultrasonic energy, with the goal of obtaining fabrics with high whiteness levels, well preserved tensile strength and higher dye uptake. The effect of the laccase enzyme and the combined laccase-hydrogen peroxide bleaching process with and without ultrasound has been investigated with regard to whiteness value, tensile strength, dyeing efficiency and dyeing kinetics using both reactive and cationic dyes. The bleached linen fabrics were characterized using X-ray diffraction and by measuring tensile strength and lightness. The dyeing efficiency and kinetics were characterized by measuring dye uptake and colour fastness. The results indicated that ultrasound was an effective technique in the combined laccase-hydrogen peroxide bleaching process of linen fabrics. The whiteness values expressed as lightness of linen fabrics is enhanced by using ultrasonic energy. The measured colour strength values were found to be slightly better for combined laccase-hydrogen peroxide/ultrasound-assisted bleached fabrics than for combined laccase-hydrogen peroxide for both reactive and cationic dyes. The fastness properties of the fabrics dyed with reactive dye were better than those obtained when using cationic dye. The time/dye uptake isotherms were also enhanced when using combined laccase-hydrogen peroxide/ultrasound-assisted bleached fabric, which confirms the efficiency of ultrasound in the combined oxidative bleaching process. The dyeing rate constant, half-time of dyeing and dyeing efficiency have been calculated and discussed.

Synthesis of tremella-like CoS and its application in sensing of hydrogen peroxide and glucose

Energy Technology Data Exchange (ETDEWEB)

Wu, Wenqin; Yu, Beibei [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Ministry of Education, College of Chemistry & Chemical Engineering, Hubei University, Wuhan 430062 (China); Wu, Huimin, E-mail: whm267@hubu.edu.cn [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Ministry of Education, College of Chemistry & Chemical Engineering, Hubei University, Wuhan 430062 (China); Wang, Shengfu; Xia, Qinghua [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Ministry of Education, College of Chemistry & Chemical Engineering, Hubei University, Wuhan 430062 (China); Ding, Yu [College of Chemistry and Materials Science, Hubei Engineering University, Xiaogan 432000 (China)

2017-01-01

Different phases of cobalt sulfides have been fabricated by one-pot hydrothermal method. Comparing all of the prepared materials, and the results revealed that CoS was the most conductive and could accelerate electron transfer. The CoS presented tremella-like and excellent catalytic activities towards hydrogen peroxide and glucose. The sensor based on CoS performed amperometric sensing of hydrogen peroxide in a linear range between 5.00 μM and 14.82 mM. Meanwhile, sensing of glucose with double-linear range, one is between 5.00 μM and 1.10 mM, the other is between 1.20 mM and 10.20 mM. These due to the fact that more and more intermediate species absorb onto electrode surface with increasing the concentration of glucose, which limit the following glucose oxidation. Furthermore, the hydrogen peroxide and glucose sensors based on tremella-like CoS also exhibited excellent selectivity, stability, and reproducibility. Thus, the sensor showed potential utilities in hydrogen peroxide and glucose detection. - Highlights: • Tremella-like CoS was prepared by an environmentally friendly hydrothermal method. • The CoS exhibited excellent catalytic activity towards hydrogen peroxide and glucose. • The sensors based on CoS can be applied to detect real samples.

The evaluation of hydrogen peroxide bleaching of Gonometa ...

African Journals Online (AJOL)

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

Petroleum Contaminated Soil Treatment Using Surfactant and Hydrogen Peroxide

Directory of Open Access Journals (Sweden)

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.

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

Directory of Open Access Journals (Sweden)

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.

Origin of the different behavior of some platinum decorated nanocarbons towards the electrochemical oxidation of hydrogen peroxide

Energy Technology Data Exchange (ETDEWEB)

Malara, A. [Dipartimento di Ingegneria dell' Informazione, delle Infrastrutture e dell' Energia Sostenibile (DIIES), Università “Mediterranea”, 89122 Reggio Calabria (Italy); Leonardi, S.G.; Bonavita, A. [Dipartimento di Ingegneria Elettronica, Chimica ed Ingegneria Industriale (DIECII), Università di Messina, 98166 Messina (Italy); Fazio, E. [Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra (MIFT), Università di Messina, 98166 Messina (Italy); Stelitano, S. [Dipartimento di Fisica (DF), Università della Calabria, 87036 Arcavacata di Rende (Italy); Neri, G. [Dipartimento di Ingegneria Elettronica, Chimica ed Ingegneria Industriale (DIECII), Università di Messina, 98166 Messina (Italy); Neri, F. [Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra (MIFT), Università di Messina, 98166 Messina (Italy); Santangelo, S., E-mail: saveria.santangelo@unirc.it [Dipartimento di Ingegneria Civile, dell' Energia, dell' Ambiente e dei Materiali (DICEAM), Università “Mediterranea”, 89122 Reggio Calabria (Italy)

2016-12-01

The electrochemical behavior of different platinum-decorated nanocarbons (Pt@C) towards the oxidation of hydrogen peroxide (H{sub 2}O{sub 2}) was investigated. Three different types of nanocarbons were considered: i) carbon black, ii) dahlia-like carbon nanohorns and iii) carbon nanotubes, which included both commercial (single-wall and multi-wall) and laboratory prepared (multi-wall) samples. Shape and size distribution of the platinum nanoparticles and morphology of the nanocarbons were analyzed by transmission electron microscopy. Their nanostructure was investigated by micro-Raman spectroscopy, while elemental composition of the samples and chemical bonding states were studied by X-ray photoelectron spectroscopy. Electrochemical behavior towards H{sub 2}O{sub 2} oxidation was evaluated by means of cyclic voltammetry modifying the working screen-printed carbon electrode surface with the prepared Pt@C nanocomposites. Data obtained suggest that the size and dispersion of the Pt nanoparticles play a key role in increasing the sensitivity towards H{sub 2}O{sub 2} detection. Thanks to the presence of smaller and more dispersed platinum particles and of a greater amount of platinum hydroxide, acting as intermediary in the H{sub 2}O{sub 2} oxidation process, Pt@dahlia-like carbon nanohorns result to be the most promising platform for the development of H{sub 2}O{sub 2} electrochemical sensors. - Highlights: • Different nanocarbons are decorated with Pt nanoparticles by wet impregnation method. • Pt@C-based hybrids are tested as active materials for sensing of hydrogen peroxide. • Sensor based on Pt@dahlia-like carbon nanohorns is the most performing device. • The origin of the different electrochemical behaviour is investigated. • Pt@C sensing performances are correlated with their structural and surface properties.

Amperometric detection of hydrogen peroxide at nano-nickel oxide/thionine and celestine blue nanocomposite-modified glassy carbon electrodes

International Nuclear Information System (INIS)

Noorbakhsh, Abdollah; Salimi, Abdollah

2009-01-01

A simple procedure was developed to prepare a glassy carbon (GC) electrode modified with nickel oxide (NiOx) nanoparticles and water-soluble dyes. By immersing the GC/NiOx modified electrode into thionine (TH) or celestine blue (CB) solutions for a short period of time (5-120 s), a thin film of the proposed molecules was immobilized onto the electrode surface. The modified electrodes showed stable and a well-defined redox couples at a wide pH range (2-12), with surface confined characteristics. In comparison to usual methods for the immobilization of dye molecules, such as electropolymerization or adsorption on the surface of preanodized electrodes, the electrochemical reversibility and stability of these modified electrodes have been improved. The surface coverage and heterogeneous electron transfer rate constants (k s ) of thionin and celestin blue immobilized on a NiOx-GC electrode were approximately 3.5 x 10 -10 mol cm -2 , 6.12 s -1 , 5.9 x 10 -10 mol cm -2 and 6.58 s -1 , respectively. The results clearly show the high loading ability of the NiOx nanoparticles and great facilitation of the electron transfer between the immobilized TH, CB and NiOx nanoparticles. The modified electrodes show excellent electrocatalytic activity toward hydrogen peroxide reduction at a reduced overpotential. The catalytic rate constants for hydrogen peroxide reduction at GC/NiOx/CB and GC/NiOx/TH were 7.96 (±0.2) x 10 3 M -1 s -1 and 5.5 (±0.2) x 10 3 M -1 s -1 , respectively. The detection limit, sensitivity and linear concentration range for hydrogen peroxide detection were 1.67 μM, 4.14 nA μM -1 nA μM -1 and 5 μM to 20 mM, and 0.36 μM, 7.62 nA μM -1 , and 1 μM to 10 mM for the GC/NiOx/TH and GC/NiOx/CB modified electrodes, respectively. Compared to other modified electrodes, these modified electrodes have many advantages, such as remarkable catalytic activity, good reproducibility, simple preparation procedures and long-term stabilities of signal responses during

Spectroscopic studies of europium-tetracyclines complexes and their applications in detection of hydrogen peroxide and urea peroxide

International Nuclear Information System (INIS)

Grasso, Andrea Nastri

2010-01-01

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)

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

Directory of Open Access Journals (Sweden)

Stepanskyi D.O.

2017-06-01

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

Kinetics of oxidation of bilirubin and its protein complex by hydrogen peroxide in aqueous solutions

Science.gov (United States)

Solomonov, A. V.; Rumyantsev, E. V.; Antina, E. V.

2010-12-01

A comparative study of oxidation reactions of bilirubin and its complex with albumin was carried out in aqueous solutions under the action of hydrogen peroxide and molecular oxygen at different pH values. Free radical oxidation of the pigment in both free and bound forms at pH 7.4 was shown not to lead to the formation of biliverdin, but to be associated with the decomposition of the tetrapyrrole chromophore into monopyrrolic products. The effective and true rate constants of the reactions under study were determined. It was assumed that one possible mechanism of the oxidation reaction is associated with the interaction of peroxyl radicals and protons of the NH groups of bilirubin molecules at the limiting stage with the formation of a highly reactive radical intermediate. The binding of bilirubin with albumin was found to result in a considerable reduction in the rate of the oxidation reaction associated with the kinetic manifestation of the protein protection effect. It was found that the autoxidation of bilirubin by molecular oxygen with the formation of biliverdin at the intermediate stage can be observed with an increase in the pH of solutions.

Oxidative and Molecular Responses in Capsicum annuum L. after Hydrogen Peroxide, Salicylic Acid and Chitosan Foliar Applications

Science.gov (United States)

Mejía-Teniente, Laura; de Dalia Durán-Flores, Flor; Chapa-Oliver, Angela María; Torres-Pacheco, Irineo; Cruz-Hernández, Andrés; González-Chavira, Mario M.; Ocampo-Velázquez, Rosalía V.; Guevara-González, Ramón G.

2013-01-01

Hydrogen peroxide (H2O2) is an important ROS molecule (Reactive oxygen species) that serves as a signal of oxidative stress and activation of signaling cascades as a result of the early response of the plant to biotic stress. This response can also be generated with the application of elicitors, stable molecules that induce the activation of transduction cascades and hormonal pathways, which trigger induced resistance to environmental stress. In this work, we evaluated the endogenous H2O2 production caused by salicylic acid (SA), chitosan (QN), and H2O2 elicitors in Capsicum annuum L. Hydrogen peroxide production after elicitation, catalase (CAT) and phenylalanine ammonia lyase (PAL) activities, as well as gene expression analysis of cat1, pal, and pathogenesis-related protein 1 (pr1) were determined. Our results displayed that 6.7 and 10 mM SA concentrations, and, 14 and 18 mM H2O2 concentrations, induced an endogenous H2O2 and gene expression. QN treatments induced the same responses in lesser proportion than the other two elicitors. Endogenous H2O2 production monitored during several days, showed results that could be an indicator for determining application opportunity uses in agriculture for maintaining plant alert systems against a stress. PMID:23676352

Antioxidative effects of fermented sesame sauce against hydrogen peroxide-induced oxidative damage in LLC-PK1 porcine renal tubule cells

Science.gov (United States)

Song, Jia-Le; Choi, Jung-Ho; Seo, Jae-Hoon; Kil, Jeung-Ha

2014-01-01

BACKGROUND/OBJECTIVES This study was performed to investigate the in vitro antioxidant and cytoprotective effects of fermented sesame sauce (FSeS) against hydrogen peroxide (H2O2)-induced oxidative damage in renal proximal tubule LLC-PK1 cells. MATERIALS/METHODS 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical (•OH), and H2O2 scavenging assay was used to evaluate the in vitro antioxidant activity of FSeS. To investigate the cytoprotective effect of FSeS against H2O2-induced oxidative damage in LLC-PK1 cells, the cellular levels of reactive oxygen species (ROS), lipid peroxidation, and endogenous antioxidant enzymes including catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-px) were measured. RESULTS The ability of FSeS to scavenge DPPH, •OH and H2O2 was greater than that of FSS and AHSS. FSeS also significantly inhibited H2O2-induced (500 µM) oxidative damage in the LLC-PK1 cells compared to FSS and AHSS (P sauces, FSeS also significantly increased cellular CAT, SOD, and GSH-px activities and mRNA expression (P < 0.05). CONCULUSIONS These results from the present study suggest that FSeS is an effective radical scavenger and protects against H2O2-induced oxidative damage in LLC-PK1 cells by reducing ROS levels, inhibiting lipid peroxidation, and stimulating antioxidant enzyme activity. PMID:24741396

Oxidative stress protection and glutathione metabolism in response to hydrogen peroxide and menadione in riboflavinogenic fungus Ashbya gossypii.

Science.gov (United States)

Kavitha, S; Chandra, T S

2014-11-01

Ashbya gossypii is a plant pathogen and a natural overproducer of riboflavin and is used for industrial riboflavin production. A few literature reports depict a link between riboflavin overproduction and stress in this fungus. However, the stress protection mechanisms and glutathione metabolism are not much explored in A. gossypii. In the present study, an increase in the activity of catalase and superoxide dismutase was observed in response to hydrogen peroxide and menadione. The lipid peroxide and membrane lipid peroxide levels were increased by H2O2 and menadione, indicating oxidative damage. The glutathione metabolism was altered with a significant increase in oxidized glutathione (GSSG), glutathione peroxidase (GPX), glutathione S transferase (GST), and glutathione reductase (GR) and a decrease in reduced glutathione (GSH) levels in the presence of H2O2 and menadione. Expression of the genes involved in stress mechanism was analyzed in response to the stressors by semiquantitative RT-PCR. The messenger RNA (mRNA) levels of CTT1, SOD1, GSH1, YAP1, and RIB3 were increased by H2O2 and menadione, indicating the effect of stress at the transcriptional level. A preliminary bioinformatics study for the presence of stress response elements (STRE)/Yap response elements (YRE) depicted that the glutathione metabolic genes, stress genes, and the RIB genes hosted either STRE/YRE, which may enable induction of these genes during stress.

Interaction of Polyamines, Abscisic Acid, Nitric Oxide, and Hydrogen Peroxide under Chilling Stress in Tomato (Lycopersicon esculentum Mill.) Seedlings

OpenAIRE

Diao, Qiannan; Song, Yongjun; Shi, Dongmei; Qi, Hongyan

2017-01-01

Polyamines (PAs) play a vital role in the responses of higher plants to abiotic stresses. However, only a limited number of studies have examined the interplay between PAs and signal molecules. The aim of this study was to elucidate the cross-talk among PAs, abscisic acid (ABA), nitric oxide (NO), and hydrogen peroxide (H2O2) under chilling stress conditions using tomato seedlings [(Lycopersicon esculentum Mill.) cv. Moneymaker]. The study showed that during chilling stress (4°C; 0, 12, and 2...

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

International Nuclear Information System (INIS)

Zhang Fugen; Wu Jilan

2002-01-01

γ irradiated rutin-, catechin-and baicalin-HCOONa aqueous solutions saturated with N 2 O:O 2 = 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 N 2 O:O 2 = 4:1 were determined to be 8.3 +- 0.2, 5.6 +- 0.2, and 7.8 +- 0.2, separately

Carbon catalysts for electrochemical hydrogen peroxide production in acidic media

DEFF Research Database (Denmark)

Čolić, Viktor; Yang, Sungeun; Révay, Zsolt

2018-01-01

Hydrogen peroxide is a commodity chemical, as it is an environmentally friendly oxidant. The electrochemical production of H2O2 from oxygen and water by the reduction of oxygen is of great interest, as it would allow the decentralized, on-site, production of pure H2O2. The ability to run...... the reaction in an acidic electrolyte with high performance is particularly important, as it would allow the use of polymer solid electrolytes and the production of pH-neutral hydrogen peroxide. Carbon catalysts, which are cheap, abundant, durable and can be highly selective show promise as potential catalysts...... for such systems. In this work, we examine the electrocatalytic performance and properties of seven commercially available carbon materials for H2O2 production by oxygen electroreduction. We show that the faradaic efficiencies for the reaction lie in a wide range of 18-82% for different carbon catalysts. In order...

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

Energy Technology Data Exchange (ETDEWEB)

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

2009-01-01

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

Review of the methods to form hydrogen peroxide in electrical discharge plasma with liquid water

Science.gov (United States)

Locke, Bruce R.; Shih, Kai-Yuan

2011-06-01

This paper presents a review of the literature dealing with the formation of hydrogen peroxide from plasma processes. Energy yields for hydrogen peroxide generation by plasma from water span approximately three orders of magnitude from 4 × 10-2 to 80 g kWh-1. A wide range of plasma processes from rf to pulsed, ac, and dc discharges directly in the liquid phase have similar energy yields and may thus be limited by radical quenching processes at the plasma-liquid interface. Reactor modification using discharges in bubbles and discharges over the liquid phase can provide modest improvements in energy yield over direct discharge in the liquid, but the interpretation is complicated by additional chemical reactions of gas phase components such as ozone and nitrogen oxides. The highest efficiency plasma process utilizes liquid water droplets that may enhance efficiency by sequestering hydrogen peroxide in the liquid and by suppressing decomposition reactions by radicals from the gas and at the interface. Kinetic simulations of water vapor reported in the literature suggest that plasma generation of hydrogen peroxide should approach 45% of the thermodynamics limit, and this fact coupled with experimental studies demonstrating improvements with the presence of the condensed liquid phase suggest that further improvements in energy yield may be possible. Plasma generation of hydrogen peroxide directly from water compares favorably with a number of other methods including electron beam, ultrasound, electrochemical and photochemical methods, and other chemical processes.

Review of the methods to form hydrogen peroxide in electrical discharge plasma with liquid water

Energy Technology Data Exchange (ETDEWEB)

Locke, Bruce R; Shih, Kai-Yuan [Department of Chemical and Biomedical Engineering, Florida State University, Tallahassee, FL 32310 (United States)

2011-06-15

This paper presents a review of the literature dealing with the formation of hydrogen peroxide from plasma processes. Energy yields for hydrogen peroxide generation by plasma from water span approximately three orders of magnitude from 4 x 10{sup -2} to 80 g kWh{sup -1}. A wide range of plasma processes from rf to pulsed, ac, and dc discharges directly in the liquid phase have similar energy yields and may thus be limited by radical quenching processes at the plasma-liquid interface. Reactor modification using discharges in bubbles and discharges over the liquid phase can provide modest improvements in energy yield over direct discharge in the liquid, but the interpretation is complicated by additional chemical reactions of gas phase components such as ozone and nitrogen oxides. The highest efficiency plasma process utilizes liquid water droplets that may enhance efficiency by sequestering hydrogen peroxide in the liquid and by suppressing decomposition reactions by radicals from the gas and at the interface. Kinetic simulations of water vapor reported in the literature suggest that plasma generation of hydrogen peroxide should approach 45% of the thermodynamics limit, and this fact coupled with experimental studies demonstrating improvements with the presence of the condensed liquid phase suggest that further improvements in energy yield may be possible. Plasma generation of hydrogen peroxide directly from water compares favorably with a number of other methods including electron beam, ultrasound, electrochemical and photochemical methods, and other chemical processes.

Salinity-gradient energy driven microbial electrosynthesis of hydrogen peroxide

DEFF Research Database (Denmark)

Li, Xiaohu; Angelidaki, Irini; Zhang, Yifeng

2017-01-01

Hydrogen peroxide (H2O2) as a strong oxidant, is widely used in various chemical industries and environmental remediation processes. In this study, we developed an innovative method for cost-effective production of H2O2 by using a microbial reverse-electrodialysis electrolysis cell (MREC). In the......Hydrogen peroxide (H2O2) as a strong oxidant, is widely used in various chemical industries and environmental remediation processes. In this study, we developed an innovative method for cost-effective production of H2O2 by using a microbial reverse-electrodialysis electrolysis cell (MREC......). In the MREC, electrical potential generated by the exoelectrogens and the salinity-gradient between salt and fresh water were utilized to drive the high-rate H2O2 production. Operational parameters such as air flow rate, pH, cathodic potential, flow rate of salt and fresh water were investigated. The optimal...... H2O2 production was observed at salt and fresh water flow rate of 0.5 mL min−1, air flow rate of 12–20 mL min−1, cathode potential of −0.485 ± 0.025 V (vs Ag/AgCl). The maximum H2O2 accumulated concentration of 778 ± 11 mg L−1 was obtained at corresponding production rate of 11.5 ± 0.5 mg L−1 h−1...

Hydrogen Peroxide Cycling in Acidic Geothermal Environments and Potential Implications for Oxidative Stress

Science.gov (United States)

Mesle, M.; Beam, J.; Jay, Z.; Bodle, B.; Bogenschutz, E.; Inskeep, W.

2014-12-01

Hydrogen peroxide (H2O2) may be produced in natural waters via photochemical reactions between dissolved oxygen, organic carbon and light. Other reactive oxygen species (ROS) such as superoxide and hydroxyl radicals are potentially formed in environments with high concentrations of ferrous iron (Fe(II), ~10-100 μM) by reaction between H2O2 and Fe(II) (i.e., Fenton chemistry). Thermophilic archaea and bacteria inhabiting acidic iron-oxide mats have defense mechanisms against both extracellular and intracellular peroxide, such as peroxiredoxins (which can degrade H2O2) and against other ROS, such as superoxide dismutases. Biological cycling of H2O2 is not well understood in geothermal ecosystems, and geochemical measurements combined with molecular investigations will contribute to our understanding of microbial response to oxidative stress. We measured H2O2 and other dissolved compounds (Fe(II), Fe(III), H2S, O2), as well as photon flux, pH and temperature, over time in surface geothermal waters of several acidic springs in Norris Geyser Basin, Yellowstone National Park, WY (Beowulf Spring and One Hundred Spring Plain). Iron-oxide mats were sampled in Beowulf Spring for on-going analysis of metatranscriptomes and RT-qPCR assays of specific stress-response gene transcription (e.g., superoxide dismutases, peroxiredoxins, thioredoxins, and peroxidases). In situ analyses show that H2O2 concentrations are lowest in the source waters of sulfidic systems (ca. 1 μM), and increase by two-fold in oxygenated waters corresponding to Fe(III)-oxide mat formation (ca. 2 - 3 μM). Channel transects confirm increases in H2O2 as a function of oxygenation (distance). The temporal dynamics of H2O2, O2, Fe(II), and H2S in Beowulf geothermal waters were also measured during a diel cycle, and increases in H2O2 were observed during peak photon flux. These results suggest that photochemical reactions may contribute to changes in H2O2. We hypothesize that increases in H2O2 and O2

A biosensor for hydrogen peroxide detection based on electronic properties of carbon nanotubes

Science.gov (United States)

Majidi, Roya

2013-01-01

Density functional theory has been used to study the effect of hydrogen peroxide on the electronic properties of single walled carbon nanotubes. The metallic and semiconducting carbon nanotubes have been considered in the presence of different number of hydrogen peroxide. The results indicate that hydrogen peroxide has no significant effect on the metallic nanotube and these nanotubes remain to be metallic. In contrast, the electronic properties of the semiconducting nanotubes are so sensitive to hydrogen peroxide. The energy band gap of these nanotubes is decreased by increasing the number of hydrogen peroxide. The electronic sensivity of the carbon nanotubes to hydrogen peroxide opens new insights into developing biosensors based on the single walled carbon nanotubes.

The oxidative dissolution of unirradiated UO2 by hydrogen peroxide as a function of pH

International Nuclear Information System (INIS)

Clarens, F.; Pablo, J. de; Casas, I.; Gimenez, J.; Rovira, M.; Merino, J.; Cera, E.; Bruno, J.; Quinones, J.; Martinez-Esparza, A.

2005-01-01

The dissolution of non-irradiated UO 2 was studied as a function of both pH and hydrogen peroxide concentration (simulating radiolytic generated product). At acidic pH and a relatively low hydrogen peroxide concentration (10 -5 mol dm -3 ), the UO 2 dissolution rate decreases linearly with pH while at alkaline pH the dissolution rate increases linearly with pH. At higher H 2 O 2 concentrations (10 -3 mol dm -3 ) the dissolution rates are lower than the ones at 10 -5 mol dm -3 H 2 O 2 , which has been attributed to the precipitation at these conditions of studtite (UO 4 . 4H 2 O, which was identified by X-ray diffraction), together with the possibility of hydrogen peroxide decomposition. In the literature, spent fuel dissolution rates determined in the absence of carbonate fall in the H 2 O 2 concentration range 5 x 10 -7 - 5 x 10 -5 mol dm -3 according to our results, which is in agreement with H 2 O 2 concentrations determined in spent fuel leaching experiments

Transition metal-free oxidation of benzylic alcohols to carbonyl compounds by hydrogen peroxide in the presence of acidic silica gel

Directory of Open Access Journals (Sweden)

Hossein Ghafuri

2015-01-01

Full Text Available Oxidation of alcohols to carbonyl compounds has become an important issue in the process industry as well as many other applications. In this method, various benzylic alcohols were successfully converted to corresponding aldehydes and ketones under transition metal-free condition using hydrogen peroxide in the presence of some amount of catalytic acidic silica gel. Silica gel is inexpensive and available. One of the most important features of this method is its short reaction time.

Numerical and experimental analysis of heat transfer in injector plate of hydrogen peroxide hybrid rocket motor

Science.gov (United States)

Cai, Guobiao; Li, Chengen; Tian, Hui

2016-11-01

This paper is aimed to analyze heat transfer in injector plate of hydrogen peroxide hybrid rocket motor by two-dimensional axisymmetric numerical simulations and full-scale firing tests. Long-time working, which is an advantage of hybrid rocket motor over conventional solid rocket motor, puts forward new challenges for thermal protection. Thermal environments of full-scale hybrid rocket motors designed for long-time firing tests are studied through steady-state coupled numerical simulations of flow field and heat transfer in chamber head. The motor adopts 98% hydrogen peroxide (98HP) oxidizer and hydroxyl-terminated poly-butadiene (HTPB) based fuel as the propellants. Simulation results reveal that flowing liquid 98HP in head oxidizer chamber could cool the injector plate of the motor. The cooling of 98HP is similar to the regenerative cooling in liquid rocket engines. However, the temperature of the 98HP in periphery portion of the head oxidizer chamber is higher than its boiling point. In order to prevent the liquid 98HP from unexpected decomposition, a thermal protection method for chamber head utilizing silica-phenolics annular insulating board is proposed. The simulation results show that the annular insulating board could effectively decrease the temperature of the 98HP in head oxidizer chamber. Besides, the thermal protection method for long-time working hydrogen peroxide hybrid rocket motor is verified through full-scale firing tests. The ablation of the insulating board in oxygen-rich environment is also analyzed.

Optical determination of glucose and hydrogen peroxide using a nanocomposite prepared from glucose oxidase and magnetite nanoparticles immobilized on graphene oxide

International Nuclear Information System (INIS)

Chang, Qing; Tang, Heqing

2014-01-01

Fe 3 O 4 nanoparticles were deposited on sheets of graphene oxide (GO) by a precipitation method, and glucose oxidase (GOx) was then immobilized on this material to produce a GOx/Fe 3 O 4 /GO magnetic nanocomposite containing crosslinked enzyme clusters. The 3-component composite functions as a binary enzyme that was employed in a photometric method for the determination of glucose and hydrogen peroxide where the GOx/Fe 3 O 4 /GO nanoparticles cause the generation of H 2 O 2 which, in turn, oxidize the substrate N,N-diethyl-p-phenylenediamine to form a purple product with an absorption maximum at 550 nm. The absorbance at 550 nm can be correlated to the concentration of glucose and/or hydrogen peroxide. Under optimized conditions, the calibration plot is linear in the 0.5 to 600 μM glucose concentration range, and the detection limit is 0.2 μM. The respective plot for H 2 O 2 ranges from 0.1 to 10 μM, and the detection limit is 0.04 μM. The method was successfully applied to the determination of glucose in human serum samples. The GOx/Fe 3 O 4 /GO nanoparticles are reusable. (author)

Can aqueous hydrogen peroxide be used as a stand-alone energy source?

International Nuclear Information System (INIS)

Disselkamp, Robert S.

2010-01-01

A novel electrochemical scheme to convert a stand-alone supply of aqueous hydrogen peroxide into a fuel cell-ready stream of hydrogen gas plus aqueous hydrogen peroxide is described. The electrochemical cell, consisting of a solid base and solid acid electrocatalyst, together with a proton exchange membrane, comprise the system that converts aqueous hydrogen peroxide into separate gas streams of oxygen and hydrogen. Aqueous hydrogen peroxide is contained in the anode compartment only and exists in the region where oxygen gas is formed, whereas the cathode compartment is where hydrogen gas is generated and therefore exists in a reduced state. A near zero theoretical over-potential can be achieved by the choice of basicity and acidity of the electrode materials. The primary cost of the electrochemical cell is electrode construction and the aqueous hydrogen peroxide energy storage compound. Additional research effort is required to experimentally validate the concept and explore the full economic impact should initial studies, based on the design presented here, prove promising. (author)

Determination of molybdenum (VI) by its catalytic effect on the oxidation of nile blue by hydrogen peroxide

International Nuclear Information System (INIS)

Ensafi, Ali A.; Sadeghie, Majid M.; Alaie-Yazdie, F.

1998-01-01

A spectrophotometric reaction rate method for the determination of molybdenum is described, based on its catalytic effect on the oxidation of nile blue by hydrogen peroxide. The decrease in absorbance of nile blue with time from 0.5 to 4 min at 590 nm is proportional to the concentration of Mo(VI) over the range 0.022-1000 μg/ml. The limit of detection of molybdenum(VI) is 0.008 μg/ml. The precision and the effect of more than forty ions are reported. The procedure has been successfully applied for the determination of molybdenum (VI) in plant materials and steel samples. (author)

Gene polymorphisms against DNA damage induced by hydrogen peroxide in leukocytes of healthy humans through comet assay: a quasi-experimental study

Directory of Open Access Journals (Sweden)

Klautau-Guimarães Maria N

2010-05-01

Full Text Available Abstract Background Normal cellular metabolism is well established as the source of endogenous reactive oxygen species which account for the background levels of oxidative DNA damage detected in normal tissue. Hydrogen peroxide imposes an oxidative stress condition on cells that can result in DNA damage, leading to mutagenesis and cell death. Several potentially significant genetic variants related to oxidative stress have already been identified, and angiotensin I-converting enzyme (ACE inhibitors have been reported as possible antioxidant agents that can reduce vascular oxidative stress in cardiovascular events. Methods We investigate the influences of haptoglobin, manganese superoxide dismutase (MnSOD Val9Ala, catalase (CAT -21A/T, glutathione peroxidase 1 (GPx-1 Pro198Leu, ACE (I/D and gluthatione S-transferases GSTM1 and GSTT1 gene polymorphisms against DNA damage and oxidative stress. These were induced by exposing leukocytes from peripheral blood of healthy humans (N = 135 to hydrogen peroxide (H2O2, and the effects were tested by comet assay. Blood samples were submitted to genotyping and comet assay (before and after treatment with H2O2 at 250 μM and 1 mM. Results After treatment with H2O2 at 250 μM, the GPx-1 polymorphism significantly influenced results of comet assay and a possible association of the Pro/Leu genotype with higher DNA damage was found. The highest or lowest DNA damage also depended on interaction between GPX-1/ACE and Hp/GSTM1T1 polymorphisms when hydrogen peroxide treatment increased oxidative stress. Conclusions The GPx-1 polymorphism and the interactions between GPX-1/ACE and Hp/GSTM1T1 can be determining factors for DNA oxidation provoked by hydrogen peroxide, and thus for higher susceptibility to or protection against oxidative stress suffered by healthy individuals.

Influence of ionizing radiation on the catalytic properties of oxide catalysts tested by hydrogen peroxide decomposition

International Nuclear Information System (INIS)

Mucka, V.

1987-01-01

Results of a study of some physical and catalytic properties of different oxide catalysts as affected by ionizing radiation (γ, n, e - ) and tested by the decomposition of hydrogen peroxide in aqueous solution are presented in this paper. The oxidation state of the active component present on the catalyst surface was found to be one of the most sensitive properties to the ionizing radiation. Changes of this state induced by γ-irradiation were found to be positive in most cases; electron pre-irradiation of the oxides leads, as a rule, to negative effects and the effects of neutron irradiation may be positive or negative. On the other hand, changes in the catalytic activity of the oxides after γ-or electron-irradiation seem to be mostly negative and positive, respectively; the effects of fast neutrons seem to vary here. Neither quantitative or qualitative correlation was found between the radiation-induced changes in these two quantities. The results give evidence that ionizing radiation principally affects the surface concentration of the catalytic sites. Both the character and magnitude of the changes in surface oxidation abilities and in catalytic activities of the oxide catalysts seem to be dependent upon the actual state of the catalyst surface. (author)

The effect of hydrogen peroxide and ultraviolet irradiation on non-sporing bacteria

International Nuclear Information System (INIS)

Bayliss, C.E.; Waites, W.M.

1980-01-01

A kill of 99.99% was obtained in cell suspensions of Escherichia coli and Streptococcus faecalis by incubation with hydrogen peroxide 1.0%(w/v) for 75 and 180 min respectively. The same kill was produced by 30s irradiation with ultraviolet (u.v.) light in the presence of hydrogen peroxide 1.0% (w/v). This simultaneous treatment with u.v. and hydrogen peroxide produced a synergistic kill at least 30-fold greater than that produced by irradiation of cell suspensions of Esch. coli with or without subsequent incubation with hydrogen peroxide. (author)

Thiol peroxidases mediate specific genome-wide regulation of gene expression in response to hydrogen peroxide

OpenAIRE

Fomenko, Dmitri E.; Koc, Ahmet; Agisheva, Natalia; Jacobsen, Michael; Kaya, Alaattin; Malinouski, Mikalai; Rutherford, Julian C.; Siu, Kam-Leung; Jin, Dong-Yan; Winge, Dennis R.; Gladyshev, Vadim N.

2011-01-01

Hydrogen peroxide is thought to regulate cellular processes by direct oxidation of numerous cellular proteins, whereas antioxidants, most notably thiol peroxidases, are thought to reduce peroxides and inhibit H2O2 response. However, thiol peroxidases have also been implicated in activation of transcription factors and signaling. It remains unclear if these enzymes stimulate or inhibit redox regulation and whether this regulation is widespread or limited to a few cellular components. Herein, w...

New Trends in Oxidative Functionalization of Carbon–Hydrogen Bonds: A Review

Directory of Open Access Journals (Sweden)

Georgiy B. Shul’pin

2016-03-01

Full Text Available This review describes new reactions catalyzed by recently discovered types of metal complexes and catalytic systems (catalyst + co-catalyst. Works of recent years (mainly 2010–2016 devoted to the oxygenations of saturated, aromatic hydrocarbons and other carbon–hydrogen compounds are surveyed. Both soluble metal complexes and solid metal compounds catalyze such transformations. Molecular oxygen, hydrogen peroxide, alkyl peroxides, and peroxy acids were used in these reactions as oxidants.

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

Science.gov (United States)

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.

Protein oxidation and peroxidation

DEFF Research Database (Denmark)

Davies, Michael Jonathan

2016-01-01

Proteins are major targets for radicals and two-electron oxidants in biological systems due to their abundance and high rate constants for reaction. With highly reactive radicals damage occurs at multiple side-chain and backbone sites. Less reactive species show greater selectivity with regard...... to the residues targeted and their spatial location. Modification can result in increased side-chain hydrophilicity, side-chain and backbone fragmentation, aggregation via covalent cross-linking or hydrophobic interactions, protein unfolding and altered conformation, altered interactions with biological partners...... and modified turnover. In the presence of O2, high yields of peroxyl radicals and peroxides (protein peroxidation) are formed; the latter account for up to 70% of the initial oxidant flux. Protein peroxides can oxidize both proteins and other targets. One-electron reduction results in additional radicals...

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

Directory of Open Access Journals (Sweden)

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.

Combination process method of lactic acid hydrolysis and hydrogen peroxide oxidation for cassava starch modification

Science.gov (United States)

Sumardiono, Siswo; Pudjihastuti, Isti; Budiyono, Hartanto, Hansen; Sophiana, Intan Clarissa

2017-05-01

Indonesia is one of the world's largest wheat importer, some research are conducted to find other carbohydrate sources which can replace wheat. Cassava is very easy to find and grown in tropical climates especially Indonesia. The research is focused on cassava starch modification as a substitute for wheat flour in order to reduce consumption of wheat flour. The aim of this research is to assess the effect of temperature, pH, and the concentration of H2O2 in modifying cassava starch which. The combination methods are lactic acid hydroxylation and hydrogen peroxide oxidation to improve baking expansion. The carboxyl group, carbonyl group, swelling power, starch solubility, and baking expansion of starch are analized and calculated. Results showed that the modified cassava starch can substitute wheat flour with optimum conditions process at a concentration of H2O2 is 1.5% w/w, oxidation temperature is 50°C, and pH is 3 by the value of swelling power is 6.82%, solubility is 0.02%, and baking expansion is 7.2 cm3/gram.

Ambient pressure microplasmas for the direct synthesis of Hydrogen Peroxide in the gas phase

NARCIS (Netherlands)

Vasko, C.A.; Bruggeman, P.J.

2011-01-01

In this work, a plasma generates hydrogen peroxide (H2O2) to be used for the insitu epoxidation of propene to propene oxide, a major bulk material in the chemical industry. Microplasmas can improve the overall cost-effectiveness of an industrial production process and are especially suitable for

In-situ synthesis of hydrogen peroxide in a novel Zn-CNTs-O2 system

Science.gov (United States)

Gong, Xiao-bo; Yang, Zhao; Peng, Lin; Zhou, An-lan; Liu, Yan-lan; Liu, Yong

2018-02-01

A novel strategy of in-situ synthesis of hydrogen peroxide (H2O2) was formulated and evaluated. Oxygen was selectively reduced to H2O2 combined with electrochemical corrosion of zinc in the Zn-CNTs-O2 system. The ratio of zinc and CNTs, heat treatment temperature, and operational parameters such as composite dosage, initial pH, solution temperature, oxygen flow rate were systematically investigated to improve the efficiency of H2O2 generation. The Zn-CNTs composite (weight ratio of 2.5:1) prepared at 500 °C showed the maximum H2O2 accumulation concentration of 293.51 mg L-1 within 60 min at the initial pH value of 3.0, Zn-CNTs dosage of 0.4 g and oxygen flow rate of 400 mL min-1. The oxygen was reduced through two-electron pathway to hydrogen peroxide on CNTs while the zinc was oxidized in the system and the dissolved zinc ions convert to zinc hydroxide and depositing on the surface of CNTs. It was proposed that the increment of direct H2O2 production was caused by the improvement of the formed Zn/CNTs corrosion cell. This provides promising strategy for in-situ synthesis and utilization of hydrogen peroxide in the novel Zn-CNTs-O2 system, which enhances the environmental and economic attractiveness of the use of H2O2 as green oxidant for wastewater treatments.

Hydrogen peroxide and radiation water chemistry of boiling water reactors

International Nuclear Information System (INIS)

Ibe, E.; Watanabe, A.; Endo, M.; Takahashi, M.; Karasawa, H.

1991-01-01

G-values and rate constants at elevated temperature are reviewed and updated for computer simulation of water radiolysis in BWRs. Quantitative relationship between g-values of H 2 and OH was found out to govern numerically the radiolytic environment in the BWR primary system. Thermal decomposition of hydrogen peroxide was measured in stagnant water in a quartz cell and the rate constant was determined at 2.4 x 10 -7 s -1 with the activation energy of 53.3 kJ/mol. Behaviors of hydrogen peroxide under HWC simulated with updated variables were consistent with plant observation at Forsmark 1 and 2. The most likely decomposition scheme of hydrogen peroxide at surface was identified as H 2 O 2 → H + HO 2 . Based on the surface decomposition process, actual level of hydrogen peroxide was estimated at 200-400 ppb under NWC condition from measured at BWR sampling stations. The estimation was consistent with the numerical simulation of BWR water radiolysis with updated variables. (author)

Determination of peracetic acid and hydrogen peroxide in the mixture

OpenAIRE

Bodiroga Milanka; Ognjanović Jasminka

2002-01-01

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

Separation of pure Cerium oxides from rare earth compounds. Homogeneous precipitation using Urea-Hydrogen Peroxide

International Nuclear Information System (INIS)

Umeda, K.; Abrao, E.

1975-01-01

The obtainment of ceric oxide (CeO 2 ) of purity higher than 97% by application of homogeneous precipitation technique is described. The selective separation of cerium was reached by hydrolysis of urea in the presence of hydrogen peroxide, using a rare earths concentrate named rare earths chloride, a natural mixture of all lanthanides provenient from the industrialization of monazite. The best conditions for the preparation of CeO 2 of 94% purity are: 35-70g R 2 O 3 /1 and pH2,0 hydrolysis temperature: 88-90 0 C, urea/R 2 O 3 ratio: 4, H 2 O 2 /Ce 2 O 3 ratio: 1,5-5,0 and hydrolysis duration: 4 hours. A leaching procedure of the precipitate with 0,25-0,75M NHO 3 leads to a product of 97-99,5% CeO 2

effect of hydrogen peroxide and thiourea on dormancy breaking of ...

African Journals Online (AJOL)

ACSS

the hydrogen peroxide (H2O2) (Claassens and. Vreugdenhil, 2000; Suttle, 2004). Hence, the objective of this study was to evaluate the effects of hydrogen peroxide and thiourea on dormancy and sprouting of potato microtubers and field grown tubers is described. MATERIELS AND METHODS. Production of microtubers.

The Addition of Oxygen or Hydrogen Peroxide to Feedwater in Steam Power Plant. Thermodynamics and Morphology of Oxide-films on Iron in Neutral Aqueous Solution at Elevated Temperatures

Energy Technology Data Exchange (ETDEWEB)

Ahrnbom, Lars [AB Energikonsult/Aangpannefoereningen, S-104 20 Stockholm (SE); Lewis, Derek [AB Atomenergi, Nykoeping (Sweden)

1977-07-01

A study is reported of the oxidation of iron at temperatures up to 350 deg C in aqueous systems containing oxygen and hydrogen peroxide and in the region of acid-base neutrality. New theoretical data have been obtained for the iron-water system at elevated temperatures, these are presented in the form of pe(pH){sub T}-diagrams. They show that when pe (redox potential) is controlled by the couple O{sub 2}-H{sub 2}O{sub 2}, the thermodynamically stable form of iron at pH-values near 1/2log{sub T}K{sub W} is expected to be alpha-Fe{sub 3}O{sub 4}. Measurements have been made with oxygen and hydrogen peroxide electrodes. The results are consistent with the theoretical data. They also show that only when hydrogen peroxide is present is the redox potential buffered (poised) by a well-characterised electrode reaction with a relatively large exchange current. Adequate redox-buffering is essential if the nature of the oxide-film on iron is to be closely controlled. In experiments with mechanically polished iron-foil (99.99 % Fe), a thin film of a single spinel-phase forms on specimens exposed to dilute solutions of hydrogen peroxide in rigorously deionised water. The X-ray diffraction characteristics of this phase (a = 8.390 +- 0.003 A) are not, however, consistent with those of alpha-Fe{sub 3}O{sub 4} (a = 8.398 A) or of the defect spinel-type material designated gamma-Fe{sub 2}O{sub 3} (a = 8.381 to 8.399 A). These results are consistent with the view, advanced in other work, that the primary surface film formed on iron in water under conditions close to absolute neutrality is a defect spinel-phase stabilized by incorporated protons. This phase may correspond stoichiometrically to HFe{sub 5}O{sub 8}

Miniaturized and green method for determination of chemical oxygen demand using UV-induced oxidation with hydrogen peroxide and single drop microextraction

International Nuclear Information System (INIS)

Akhoundzadeh, Jeyran; Chamsaz, Mahmoud; Costas, Marta; Lavilla, Isela; Bendicho, Carlos

2013-01-01

We report on a green method for the determination of low levels of chemical oxygen demand. It is based on the combination of (a) UV-induced oxidation with hydrogen peroxide, (b) headspace single-drop microextraction with in-drop precipitation, and (c) micro-turbidimetry. The generation of CO 2 after photolytic oxidation followed by its sequestration onto a microdrop of barium hydroxide gives rise to a precipitate of barium carbonate which is quantified by turbidimetry. UV-light induced oxidation was studied in the absence and presence of H 2 O 2 , ultrasound, and ferrous ion. Determinations of chemical oxygen demand were performed using potassium hydrogen phthalate as a model compound. The optimized method gives a calibration curve that is linear between 3.4 and 20 mg L −1 oxygen. The detection limit was 1.2 mg L −1 of oxygen, and the repeatability (as relative standard deviation) was around 5 %. The method was successfully applied to the determination of chemical oxygen demand in different natural waters and a synthetic wastewater. (author)

Global transcriptome profile of Cryptococcus neoformans during exposure to hydrogen peroxide induced oxidative stress.

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Rajendra Upadhya

Full Text Available The ability of the opportunistic fungal pathogen Cryptococcus neoformans to resist oxidative stress is one of its most important virulence related traits. To cope with the deleterious effect of cellular damage caused by the oxidative burst inside the macrophages, C. neoformans has developed multilayered redundant molecular responses to neutralize the stress, to repair the damage and to eventually grow inside the hostile environment of the phagosome. We used microarray analysis of cells treated with hydrogen peroxide (H(2O(2 at multiple time points in a nutrient defined medium to identify a transcriptional signature associated with oxidative stress. We discovered that the composition of the medium in which fungal cells were grown and treated had a profound effect on their capacity to degrade exogenous H(2O(2. We determined the kinetics of H(2O(2 breakdown by growing yeast cells under different conditions and accordingly selected an appropriate media composition and range of time points for isolating RNA for hybridization. Microarray analysis revealed a robust transient transcriptional response and the intensity of the global response was consistent with the kinetics of H(2O(2 breakdown by treated cells. Gene ontology analysis of differentially expressed genes related to oxidation-reduction, metabolic process and protein catabolic processes identified potential roles of mitochondrial function and protein ubiquitination in oxidative stress resistance. Interestingly, the metabolic pathway adaptation of C. neoformans to H(2O(2 treatment was remarkably distinct from the response of other fungal organisms to oxidative stress. We also identified the induction of an antifungal drug resistance response upon the treatment of C. neoformans with H(2O(2. These results highlight the complexity of the oxidative stress response and offer possible new avenues for improving our understanding of mechanisms of oxidative stress resistance in C. neoformans.

Protection by the flavonoids quercetin and luteolin against peroxide- or menadione-induced oxidative stress in MC3T3-E1 osteoblast cells.

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Fatokun, Amos A; Tome, Mercedes; Smith, Robert A; Darlington, L Gail; Stone, Trevor W

2015-01-01

Potential protective effects of the flavonoids quercetin and luteolin have been examined against the oxidative stress of MC3T3-E1 osteoblast-like cells. Although hydrogen peroxide and menadione reduced cell viability, the toxicity was prevented by desferrioxamine or catalase but not superoxide dismutase, suggesting the involvement of hydrogen peroxide in both cases. Quercetin and luteolin reduced the oxidative damage, especially that caused by hydrogen peroxide. When cultures were pre-incubated with quercetin or luteolin, protection was reduced or lost. Protection was also reduced when a 24 h pre-incubation with the flavonoids was followed by exposure to menadione alone. Pretreating cultures with luteolin impaired protection by quercetin, whereas quercetin pretreatment did not affect protection by luteolin. It is concluded that quercetin and luteolin suppress oxidative damage to MC3T3-E1 cells, especially caused by peroxide. The reduction in protection by pretreatment implies a down-regulation of part of the toxic transduction pathway.

Redox Response of Reduced Graphene Oxide-Modified Glassy Carbon Electrodes to Hydrogen Peroxide and Hydrazine

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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.

Luminescent chemical waves in the Cu(II)-catalyzed oscillatory oxidation of SCN- ions with hydrogen peroxide.

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Pekala, Katarzyna; Jurczakowski, Rafał; Lewera, Adam; Orlik, Marek

2007-05-10

The oscillatory oxidation of thiocyanate ions with hydrogen peroxide, catalyzed by Cu2+ ions in alkaline media, was so far observed as occurring simultaneously in the entire space of the batch or flow reactor. We performed this reaction for the first time in the thin-layer reactor and observed the spatiotemporal course of the above process, in the presence of luminol as the chemiluminescent indicator. A series of luminescent patterns periodically starting from the random reaction center and spreading throughout the entire solution layer was reported. For a batch-stirred system, the bursts of luminescence were found to correlate with the steep decreases of the oscillating Pt electrode potential. These novel results open possibilities for further experimental and theoretical investigations of those spatiotemporal patterns, including studies of the mechanism of this chemically complex process.

Uranium precipitation with hydrogen peroxide

International Nuclear Information System (INIS)

Brown, R.A.

1980-01-01

Although hydrogen peroxide precipitation of uranium continues to be used primarily as means of producing a high purity yellowcake, it has also become an important process due to its superior physical properties. Processing costs such as filtering, drying and/or calcining and drumming, can be reduced. 5 refs

Effect of hydrodynamic cavitation on the rate of OH-radical formation in the presence of hydrogen peroxide

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Aseev, D. G.; Batoeva, A. A.

2014-01-01

It is shown experimentally that hydrogen peroxide is the source of OH-radicals at low-pressure hydrodynamic cavitation. Major preconditions for the intensification of oxidative destruction processes in organic pollutants with an added cavitation stimulus are determined.

In situ characterization of Ti-peroxy gel during formation on titanium surfaces in hydrogen peroxide containing solutions

International Nuclear Information System (INIS)

Muyco, Julie J.; Gray, Jeremy J.; Ratto, Timothy V.; Orme, Christine A.; McKittrick, Joanna; Frangos, John

2006-01-01

Three possible functions of Ti-peroxy gel are: reduction of the inflammatory response through the reduction of hydrogen peroxide and other reactive oxygen species; creation of a favorable surface for calcium phosphate nucleation; and as a transitional layer between the compliant surrounding tissue and the stiff titanium. Traditional surface characterization techniques operate in high vacuum environments that alter the actual sample-solution interface. Our studies used techniques that allowed samples to remain in solution and be observed over time. Atomic force microscopy (AFM) force-distance curves, electrochemical impedance spectroscopy (EIS), and Raman spectroscopy were each used in situ to define kinetic and mechanical properties of Ti-peroxy gel as it formed over time on titanium during exposure to hydrogen peroxide. Our studies enabled us to monitor real-time changes in the native oxide layer on titanium in hydrogen peroxide containing solution, including the formation of a Ti-peroxy gel layer above the native oxide. Peaks attributed to Ti-peroxy gel were seen to emerge over the course of several hours using in situ Raman spectroscopy. Force-distance curves suggest a layer that thickens with time on the titanium sample surface. EIS data showed that changes in the surface layers could be monitored in solution over time

Hydrogen peroxide as a fungicide for fish culture

Science.gov (United States)

Dawson, V.K.; Rach, J.J.; Schreier, Theresa M.

1994-01-01

Antifungal agents are needed to maintain healthy stocks of fish in the intensive culture systems currently employed in fish hatcheries. Malachite green has been the most widely used antifungal agent; however, its potential for producing teratology in animals and fish precludes further use in fish culture. Preliminary studies at the National Fisheries Research Center, La Crosse, WI, USA (La Crosse Center) indicate that hydrogen peroxide is effective for control of Saprolegnia sp. fungus on incubating eggs of rainbow trout. It is also effective against a wide variety of other organisms such as bacteria, yeasts, viruses, and spores, and has been proposed as a treatment for sea lice on salmon. Hydrogen peroxide and its primary decomposition products, oxygen and water, are not systemic poisons and are considered environmentally compatible. In response to a petition from the La Crosse Center, the U.S. Food and Drug Administration (FDA) recently classified hydrogen peroxide as a 'low regulatory priority' when used for control of fungus on fish and fish eggs. Preliminary tests conducted at the La Crosse Center suggest that prophylactic treatments of 250 to 500 ppm (based on 100% active ingredient) for 15 minutes every other day will inhibit fungal infections on healthy rainbow trout (Oncorhynchus mykiss) eggs. This treatment regime also seems to inhibit fungal development and increase hatching success among infected eggs. Efficacy and safety of hydrogen peroxide as a fungicide for fish are currently being evaluated.

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

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

2011-11-09

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

Treatment of palm oil mill effluent by electrocoagulation with presence of hydrogen peroxide as oxidizing agent and polialuminum chloride as coagulant-aid

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Mohd Nasrullah

2017-06-01

Full Text Available The purposes of this study were to investigate the effects of operating parameters, such as electrode material, current density, percentage of hydrogen peroxide and amount of polialuminum chloride (PAC on chemical oxygen demand (COD removal of palm oil mill effluent (POME. The current density was varied between 30–80 mA cm−2, PAC (1–3 g L−1 as coagulant-aid and 1 and 2% of hydrogen peroxide as an oxidizing agent. As for the performance of electrode type, iron was more effective than aluminum. It appeared that the removal of COD increased with the increased of current density. When PAC and H2O2 increased, the percent of COD removal was increasing as well. The overall results demonstrate that electrocoagulation is very efficient and able to achieve more than 70% COD removal in 180 min at current density 30–80 mA cm−2 reliant upon the concentration of H2O2 and PAC.

Remediation of diesel-contaminated soils using catalyzed hydrogen peroxide: a laboratory evaluation

International Nuclear Information System (INIS)

Xu, P.; Achari, G.; Mahmoud, M.; Joshi, R.C.

2002-01-01

This paper presents the results of a laboratory investigation conducted to determine the optimum amount of Fenton's reagent that allows for effective treatment of diesel-contaminated soils. Two types of soils spiked with 5,000 mg/kg diesel fuel were treated in vial reactors with varying concentrations and volumes of hydrogen peroxide. Additionally, Ottawa sand spiked with 5,000 mg/kg of diesel was treated with different H 2 O 2 to iron ratios. The gases produced during the remediation process were measured and analyzed to evaluate the oxidation of diesel range organics. As much as 40 % of diesel range organics was removed when 5 grams of silty clay were treated with 20 mL of 20 % H 2 O 2 . The same concentration and volume of hydrogen peroxide removed about 63 % of diesel range organics from sandy silt. The optimal molar ratio of H 2 O 2 : iron catalyst was found to vary between 235:1 to 490:1. (author)

A sensitive hydrogen peroxide sensor based on leaf-like silver

International Nuclear Information System (INIS)

Meng, Zuchao; Zhang, Mingyin; Zhang, Hongfang; Zheng, Jianbin

2014-01-01

A novel non-enzymatic hydrogen peroxide sensor based on leaf-like silver was constructed. The leaf-like silver was synthesized on the surface of L-cysteine (L-cys) by electrodeposition. Scanning electron microscopy and electrochemical techniques were used to characterize the leaf-like silver nanoparticles. The sensor showed high electrocatalytic activity towards the reduction of hydrogen peroxide. A wide linear range of 2.5–1.5 mM with a low detection limit of 0.7 µM was obtained. Excellent electrocatalytic activity, large surface-to-volume ratio and efficient electron transport properties of leaf-like silver have enabled stable and highly sensitive performance for the non-enzymatic hydrogen peroxide sensor. (paper)

Bromate Formation Characteristics of UV Irradiation, Hydrogen Peroxide Addition, Ozonation, and Their Combination Processes

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Naoyuki Kishimoto

2012-01-01

Full Text Available Bromate formation characteristics of six-physicochemical oxidation processes, UV irradiation, single addition of hydrogen peroxide, ozonation, UV irradiation with hydrogen peroxide addition (UV/H2O2, ozonation with hydrogen peroxide addition (O3/H2O2, and ozonation with UV irradiation (O3/UV were investigated using 1.88 μM of potassium bromide solution with or without 6.4 μM of 4-chlorobenzoic acid. Bromate was not detected during UV irradiation, single addition of H2O2, and UV/H2O2, whereas ozone-based treatments produced . Hydroxyl radicals played more important role in bromate formation than molecular ozone. Acidification and addition of radical scavengers such as 4-chlorobenzoic acid were effective in inhibiting bromate formation during the ozone-based treatments because of inhibition of hydroxyl radical generation and consumption of hydroxyl radicals, respectively. The H2O2 addition was unable to decompose 4-chlorobenzoic acid, though O3/UV and O3/H2O2 showed the rapid degradation, and UV irradiation and UV/H2O2 showed the slow degradation. Consequently, if the concentration of organic contaminants is low, the UV irradiation and/or UV/H2O2 are applicable to organic contaminants removal without bromate formation. However, if the concentration of organic contaminants is high, O3/H2O2 and O3/UV should be discussed as advanced oxidation processes because of their high organic removal efficiency and low bromate formation potential at the optimum condition.

Influence of sodium dodecyl sulfate on the reaction between Nile Blue A and hydrogen peroxide

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IVANA A. JANKOVIC

1999-05-01

Full Text Available The influence of the anionic surfactant sodium dodecyl sulfate on the rate of the reaction between the cationic form of Nile Blue A and hydrogen peroxide was investigated in the pH range from 5 to 8.5. A retardation of the oxidation of Nile Blue A with hydrogen peroxide of three orders of magnitude was observed at pH 8.5 in the presence of anionic micelles compared to the kinetic data in water. The retardation effect was less pronounced at lower pH values. These effects were explained by the electrostatic interaction of the species involved in the reaction with the negatively charged micellar surface and their effective separation in the vicinity of the micellar surface.

High levels of hydrogen peroxide in overnight tooth-whitening formulas: effects on enamel and pulp.

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Pugh, George; Zaidel, Lynette; Lin, Nora; Stranick, Michael; Bagley, Daniel

2005-01-01

Limited data are available to assess the safety of high levels of hydrogen peroxide in overnight tooth-whitening formulas. The purpose of this study was to assess the effects of hydrogen peroxide on enamel microhardness, pulp penetration, and enamel morphology. Colgate Platinum Professional Overnight Whitening System (Colgate Oral Pharmaceuticals, Inc., Canton, MA, USA) (10% carbamide peroxide, equivalent to 3.5% hydrogen peroxide) was compared with two prototype formulations containing either 7.0% or 12.0% hydrogen peroxide. In the pulp chamber studies, human extracted teeth were exposed to 3.5%, 7.0%, or 12.0% hydrogen peroxide for 30 minutes, 4 hours, or 7 hours. Microhardness, electron spectroscopy for chemical analysis, and atomic force microscopy evaluations were made from enamel blocks cut from human extracted molars. The enamel blocks were evaluated following 14 7-hour treatments (98 h total). At 7 hours' post-treatment, hydrogen peroxide penetrated the pulp chamber at 23.12 +/- 10.09, 24.58 +/- 6.90, and 26.39 +/- 5.43 microg for 3.5%, 7.0%, and 12.0% hydrogen peroxide, respectively. With regard to enamel morphology, pulp penetration, microhardness, and elemental composition, no statistically significant differences were observed between treatment groups following 98 hours of treatment. Hydrogen peroxide does not adversely affect enamel morphology or microhardness. The levels recovered in pulp indicate that hydrogen peroxide is not expected to inhibit pulpal enzymes. Overnight tray products containing levels of hydrogen peroxide of 3.5%, 7.0%, and 12.0% are not expected to adversely affect the enamel or pulpal enzymes. Additional safety studies are needed to assess the potential for tooth sensitivity and gingival irritation.

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

Science.gov (United States)

Fukuzumi, Shunichi

2016-05-01

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

Destruction of gel sulfonated cation-exchangers of the KU-2 type under the influence of hydrogen peroxide

Energy Technology Data Exchange (ETDEWEB)

Roginskaya, B.S.; Zavadovskaya, A.S.; Znamenskii, Yu.P.; Paskhina, N.A.; Dobrova, E.I.

1988-10-20

The purpose of this work was to study the mechanism of interaction of Soviet sulfonated cation-exchangers of the KU-2 type with hydrogen peroxide. It is shown that under the influence of hydrogen peroxide sulfonated cation-exchangers begin, after a certain induction period, to lose capacity and to release destruction products into water; the length of the induction period increases with the degree of cross-linking. In a given time of contact between the resin and the solution the degree of destruction falls with increase of cross-linking. The principal product of destruction of sulfonated cation-exchangers is an aromatic sulfonic acid containing oxidized groups in the side chains.

Diagnostics of Argon Injected Hydrogen Peroxide Added High Frequency Underwater Capillary Discharge

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Muhammad Waqar Ahmed

2016-05-01

Full Text Available The effects of hydrogen peroxide addition and Argon injection on electrical and spectral characteristics of underwater capillary discharge were investigated. The flowing water discharge was created in a quartz tube (Φ = 4mm outer; Φ = 2mm inner; thickness 1mm by applying high frequency (25 kHz alternating current voltage (0-15kV across the tungsten electrodes (Φ=0.5mm, in pin-pin electrode configuration, separated by a gap distance of 10 mm. The results of no hydrogen peroxide addition and no Argon gas injection were compared with addition of hydrogen peroxide and Argon injection for different values. The emission spectrum was taken to present the increase in concentration of •OH radicals with and without hydrogen peroxide addition under different argon injection rates. The results demonstrated that addition of hydrogen peroxide do not remarkably affected the conductivity of water, but its addition increased the yield rate of •OH radicals generated by plasma discharge. The addition of Argon generated bubbles and gas channels reduced the high power consumption required for inducing flowing water long gap discharge. The results showed large concentration of •OH radicals due to hydrogen peroxide addition, less required input power for generating flowing water discharge by using high frequency input voltage and due to Argon injection.

Silver-palladium catalysts for the direct synthesis of hydrogen peroxide

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

2017-11-01

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

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

NARCIS (Netherlands)

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

2012-01-01

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

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

International Nuclear Information System (INIS)

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

2013-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Čeřovský, M., E-mail: scholtz@aldebaran.cz [Institute of Chemical Technology in Prague, Department of Food Preservation, Faculty of Food and Biochemical Technology (Czech Republic); Khun, J. [Institute of Chemical Technology in Prague, Department of Physics and Measurements, Faculty of Chemical Engineering (Czech Republic); Rusová, K. [Institute of Chemical Technology in Prague, Department of Food Preservation, Faculty of Food and Biochemical Technology (Czech Republic); Scholtz, V. [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)

2013-09-15

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.

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

Science.gov (United States)

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…

Increased Production of Hydrogen Peroxide by Lactobacillus delbrueckii subsp. bulgaricus upon Aeration: Involvement of an NADH Oxidase in Oxidative Stress

Science.gov (United States)

Marty-Teysset, C.; de la Torre, F.; Garel, J.-R.

2000-01-01

The growth of Lactobacillus delbrueckii subsp. bulgaricus (L. delbrueckii subsp. bulgaricus) on lactose was altered upon aerating the cultures by agitation. Aeration caused the bacteria to enter early into stationary phase, thus reducing markedly the biomass production but without modifying the maximum growth rate. The early entry into stationary phase of aerated cultures was probably related to the accumulation of hydrogen peroxide in the medium. Indeed, the concentration of hydrogen peroxide in aerated cultures was two to three times higher than in unaerated ones. Also, a similar shift from exponential to stationary phase could be induced in unaerated cultures by adding increasing concentrations of hydrogen peroxide. A significant fraction of the hydrogen peroxide produced by L. delbrueckii subsp. bulgaricus originated from the reduction of molecular oxygen by NADH catalyzed by an NADH:H2O2 oxidase. The specific activity of this NADH oxidase was the same in aerated and unaerated cultures, suggesting that the amount of this enzyme was not directly regulated by oxygen. Aeration did not change the homolactic character of lactose fermentation by L. delbrueckii subsp. bulgaricus and most of the NADH was reoxidized by lactate dehydrogenase with pyruvate. This indicated that NADH oxidase had no (or a very small) energetic role and could be involved in eliminating oxygen. PMID:10618234

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

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Randi H. Gottfredsen

2013-01-01

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

Exogenous Melatonin Confers Cadmium Tolerance by Counterbalancing the Hydrogen Peroxide Homeostasis in Wheat Seedlings

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Jun Ni

2018-03-01

Full Text Available Melatonin has emerged as a research highlight regarding its important role in regulating plant growth and the adaptation to the environmental stresses. In this study, we investigated how melatonin prevented the cadmium toxicity to wheat seedlings. The results demonstrated that cadmium induced the expression of melatonin biosynthesis-related genes and cause a significant increase of endogenous melatonin level. Melatonin treatment drastically alleviated the cadmium toxicity, resulting in increased plant height, biomass accumulation, and root growth. Cadmium and senescence treatment significantly increased the endogenous level of hydrogen peroxide, which was strictly counterbalanced by melatonin. Furthermore, melatonin treatment caused a significant increase of GSH (reduced glutathione content and the GSH/GSSG (oxidized glutathione ratio. The activities of two key antioxidant enzymes, ascorbate peroxidase (APX and superoxide dismutase (SOD, but not catalase (CAT and peroxidase (POD, were specifically improved by melatonin. Additionally, melatonin not only promoted the primary root growth, but also drastically enhanced the capacity of the seedling roots to degrade the exogenous hydrogen peroxide. These results suggested that melatonin played a key role in maintaining the hydrogen peroxide homeostasis, via regulation of the antioxidant systems. Conclusively, this study revealed a crucial protective role of melatonin in the regulation of cadmium resistance in wheat.

Exogenous Melatonin Confers Cadmium Tolerance by Counterbalancing the Hydrogen Peroxide Homeostasis in Wheat Seedlings.

Science.gov (United States)

Ni, Jun; Wang, Qiaojian; Shah, Faheem Afzal; Liu, Wenbo; Wang, Dongdong; Huang, Shengwei; Fu, Songling; Wu, Lifang

2018-03-30

Melatonin has emerged as a research highlight regarding its important role in regulating plant growth and the adaptation to the environmental stresses. In this study, we investigated how melatonin prevented the cadmium toxicity to wheat seedlings. The results demonstrated that cadmium induced the expression of melatonin biosynthesis-related genes and cause a significant increase of endogenous melatonin level. Melatonin treatment drastically alleviated the cadmium toxicity, resulting in increased plant height, biomass accumulation, and root growth. Cadmium and senescence treatment significantly increased the endogenous level of hydrogen peroxide, which was strictly counterbalanced by melatonin. Furthermore, melatonin treatment caused a significant increase of GSH (reduced glutathione) content and the GSH/GSSG (oxidized glutathione) ratio. The activities of two key antioxidant enzymes, ascorbate peroxidase (APX) and superoxide dismutase (SOD), but not catalase (CAT) and peroxidase (POD), were specifically improved by melatonin. Additionally, melatonin not only promoted the primary root growth, but also drastically enhanced the capacity of the seedling roots to degrade the exogenous hydrogen peroxide. These results suggested that melatonin played a key role in maintaining the hydrogen peroxide homeostasis, via regulation of the antioxidant systems. Conclusively, this study revealed a crucial protective role of melatonin in the regulation of cadmium resistance in wheat.

Overoxidation of chloroplast 2-Cys peroxiredoxins: balancing toxic and signaling activities of hydrogen peroxide

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Leonor ePuerto-Galán

2013-08-01

Full Text Available Photosynthesis, the primary source of biomass and oxygen into the biosphere, involves the transport of electrons in the presence of oxygen and, therefore, chloroplasts constitute an important source of reactive oxygen species (ROS, including hydrogen peroxide. If accumulated at high level, hydrogen peroxide may exert a toxic effect; however, it is as well an important second messenger. In order to balance the toxic and signaling activities of hydrogen peroxide its level has to be tightly controlled. To this end, chloroplasts are equipped with different antioxidant systems such as 2-Cys peroxiredoxins (2-Cys Prxs, thiol-based peroxidases able to reduce hydrogen- and organic peroxides. At high peroxide concentrations the peroxidase function of 2-Cys Prxs may become inactivated through a process of overoxidation. This inactivation has been proposed to explain the signaling function of hydrogen peroxide in eukaryotes, whereas in prokaryotes, the 2-Cys Prxs of which were considered to be insensitive to overoxidation, the signaling activity of hydrogen peroxide is less relevant. Here we discuss the current knowledge about the mechanisms controlling 2-Cys Prx overoxidation in chloroplasts, organelles with an important signaling function in plants. Given the prokaryotic origin of chloroplasts, we discuss the occurrence of 2-Cys Prx overoxidation in cyanobacteria with the aim of identifying similarities between chloroplasts and their ancestors regarding their response to hydrogen peroxide.

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

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Takayuki Mokudai

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

Modelling of Impulsional pH Variations Using ChemFET-Based Microdevices: Application to Hydrogen Peroxide Detection

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Abdou Karim Diallo

2014-02-01

Full Text Available This work presents the modelling of impulsional pH variations in microvolume related to water-based electrolysis and hydrogen peroxide electrochemical oxidation using an Electrochemical Field Effect Transistor (ElecFET microdevice. This ElecFET device consists of a pH-Chemical FET (pH-ChemFET with an integrated microelectrode around the dielectric gate area in order to trigger electrochemical reactions. Combining oxidation/reduction reactions on the microelectrode, water self-ionization and diffusion properties of associated chemical species, the model shows that the sensor response depends on the main influential parameters such as: (i polarization parameters on the microelectrode, i.e., voltage (Vp and time (tp; (ii distance between the gate sensitive area and the microelectrode (d; and (iii hydrogen peroxide concentration ([H2O2]. The model developed can predict the ElecFET response behaviour and creates new opportunities for H2O2-based enzymatic detection of biomolecules.

Kinetics of the oxidation of hydrogen sulfite by hydrogen peroxide in aqueous solution:. ionic strength effects and temperature dependence

Science.gov (United States)

Maaß, Frank; Elias, Horst; Wannowius, Klaus J.

Conductometry was used to study the kinetics of the oxidation of hydrogen sulfite, HSO -3, by hydrogen peroxide in aqueous non-buffered solution at the low concentration level of 10 -5-10 -6 M, typically found in cloud water. The kinetic data confirm that the rate law reported for the pH range 3-6 at higher concentration levels, rate= kH·[H +]·[HSO -3]·[H 2O 2], is valid at the low concentration level and at low ionic strength Ic. At 298 K and Ic=1.5×10 -4 M, third-order rate constant kH was found to be kH=(9.1±0.5)×10 7 M -2 s -1. The temperature dependence of kH led to an activation energy of Ea=29.7±0.9 kJ mol -1. The effect of the ionic strength (adjusted with NaCl) on rate constant kH was studied in the range Ic=2×10 -4-5.0 M at pH=4.5-5.2 by conductometry and stopped-flow spectrophotometry. The dependence of kH on Ic can be described with a semi-empirical relationship, which is useful for the purpose of comparison and extrapolation. The kinetic data obtained are critically compared with those reported earlier.

Hydrogen peroxide: importance and determination

OpenAIRE

Mattos, Ivanildo Luiz de; Shiraishi, Karina Antonelli; Braz, Alexandre Delphini; Fernandes, João Roberto

2003-01-01

A brief discussion about the hydrogen peroxide importance and its determination is presented. It was emphasized some consideration of the H2O2 as reagent (separated or combined), uses and methods of analysis (techniques, detection limits, linear response intervals, sensor specifications). Moreover, it was presented several applications, such as in environmental, pharmaceutical, medicine and food samples.

Hydrogen peroxide stimulates cell motile activity through LPA receptor-3 in liver epithelial WB-F344 cells

Energy Technology Data Exchange (ETDEWEB)

Shibata, Ayano; Tanabe, Eriko; Inoue, Serina; Kitayoshi, Misaho; Okimoto, Souta; Hirane, Miku; Araki, Mutsumi [Division of Cancer Biology and Bioinformatics, Department of Life Science, Faculty of Science and Engineering, Kinki University, 3-4-1, Kowakae, Higashiosaka, Osaka 577-8502 (Japan); Fukushima, Nobuyuki [Division of Molecular Neurobiology, Department of Life Science, Faculty of Science and Engineering, Kinki University, 3-4-1, Kowakae, Higashiosaka, Osaka 577-8502 (Japan); Tsujiuchi, Toshifumi, E-mail: ttujiuch@life.kindai.ac.jp [Division of Cancer Biology and Bioinformatics, Department of Life Science, Faculty of Science and Engineering, Kinki University, 3-4-1, Kowakae, Higashiosaka, Osaka 577-8502 (Japan)

2013-04-12

Highlights: •Hydrogen peroxide stimulates cell motility of WB-F344 cells. •LPA{sub 3} is induced by hydrogen peroxide in WB-F344 cells. •Cell motility by hydrogen peroxide is inhibited in LPA{sub 3} knockdown cells. •LPA signaling is involved in cell migration by hydrogen peroxide. -- Abstract: Hydrogen peroxide which is one of reactive oxygen species (ROS) mediates a variety of biological responses, including cell proliferation and migration. In the present study, we investigated whether lysophosphatidic acid (LPA) signaling is involved in cell motile activity stimulated by hydrogen peroxide. The rat liver epithelial WB-F344 cells were treated with hydrogen peroxide at 0.1 or 1 μM for 48 h. In cell motility assays, hydrogen peroxide treated cells showed significantly high cell motile activity, compared with untreated cells. To measure the expression levels of LPA receptor genes, quantitative real time RT-PCR analysis was performed. The expressions of LPA receptor-3 (Lpar3) in hydrogen peroxide treated cells were significantly higher than those in control cells, but not Lpar1 and Lpar2 genes. Next, to assess the effect of LPA{sub 3} on cell motile activity, the Lpar3 knockdown cells from WB-F344 cells were also treated with hydrogen peroxide. The cell motile activity of the knockdown cells was not stimulated by hydrogen peroxide. Moreover, in liver cancer cells, hydrogen peroxide significantly activated cell motility of Lpar3-expressing cells, but not Lpar3-unexpressing cells. These results suggest that LPA signaling via LPA{sub 3} may be mainly involved in cell motile activity of WB-F344 cells stimulated by hydrogen peroxide.

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

Science.gov (United States)

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

2009-08-01

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

Proteins oxidation and autoantibodies' reactivity against hydrogen peroxide and malondialdehyde -oxidized thyroid antigens in patients' plasmas with Graves' disease and Hashimoto Thyroiditis.

Science.gov (United States)

Mseddi, Malek; Ben Mansour, Riadh; Gargouri, Bochra; Mnif, Fatma; El Ghawi, Samir; Hammami, Boutheina; Ghorbel, Abdelmonem; Abid, Mohamed; Lassoued, Saloua

2017-06-25

The aim of this study was to evaluate proteins oxidation in plasmas of two autoimmune thyroid diseases (AITD): Graves' disease (GD) and Hashimoto Thyroiditis (HT), and to determine whether oxidative modification of thyroid antigens (T.Ag) enhanced the reactivity of autoantibodies in plasmas of AITD patients compared with the reactivity towards native T.Ag. Carbonyl and thiol groups and MDA-protein adducts were assessed spectrophotometric methods in plasmas of 74 AITD patients and 65 healthy controls. The reactivities immunoglobulin (Ig)G autoantibodies towards malondialdéhyde (MDA)-modified T.Ag, hydrogen peroxide (H 2 O 2 )-modified T.Ag, native T.Ag and native derm were checked by enzyme-linked immunosorbent assay (ELISA). Evaluation of oxidized proteins exhibited high levels of MDA bound to proteins and carbonyl groups, as well as reduced thiol level in plasmas of AITD patients by comparison to healthy controls (p thyroid stimulating hormone level in HT patients in the other (r = 0.65, p < 0.001). The data suggest that high production of H 2 O 2 probably occurred during hormone synthesis could contribute to protein oxidation in AITD and to create neoepitopes responsible for autoantibody reactivity's to H 2 O 2 -oxidized T.Ag enhancement. These results provide support to the involvement of oxidative stress in AITD development and/or exacerbation. Copyright © 2017 Elsevier B.V. All rights reserved.

Low doses of ionizing radiation and hydrogen peroxide stimulate plant growth

International Nuclear Information System (INIS)

Korystov, Y.; Narimanov, A.

1997-01-01

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

PROCESS OF ELIMINATING HYDROGEN PEROXIDE IN SOLUTIONS CONTAINING PLUTONIUM VALUES

Science.gov (United States)

Barrick, J.G.; Fries, B.A.

1960-09-27

A procedure is given for peroxide precipitation processes for separating and recovering plutonium values contained in an aqueous solution. When plutonium peroxide is precipitated from an aqueous solution, the supernatant contains appreciable quantities of plutonium and peroxide. It is desirable to process this solution further to recover plutonium contained therein, but the presence of the peroxide introduces difficulties; residual hydrogen peroxide contained in the supernatant solution is eliminated by adding a nitrite or a sulfite to this solution.

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

Science.gov (United States)

Peter W. Hart; Carl Houtman; Kolby Hirth

2013-01-01

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

Lab-scale hydrogen peroxide data from ECBC

Data.gov (United States)

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

Functionalized Palladium Nanoparticles for Hydrogen Peroxide Biosensor

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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.

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

Science.gov (United States)

Derecho, I; McCoy, K B; Vaishampayan, P; Venkateswaran, K; Mogul, R

2014-10-01

The microbiological inventory of spacecraft and the associated assembly facility surfaces represent the primary pool of forward contaminants that may impact the integrity of life-detection missions. Herein, we report on the characterization of several strains of hydrogen peroxide-resistant Acinetobacter, which were isolated during the Mars Phoenix lander assembly. All Phoenix-associated Acinetobacter strains possessed very high catalase specific activities, and the specific strain, A. gyllenbergii 2P01AA, displayed a survival against hydrogen peroxide (no loss in 100 mM H2O2 for 1 h) that is perhaps the highest known among Gram-negative and non-spore-forming bacteria. Proteomic characterizations reveal a survival mechanism inclusive of proteins coupled to peroxide degradation (catalase and alkyl hydroperoxide reductase), energy/redox management (dihydrolipoamide dehydrogenase), protein synthesis/folding (EF-G, EF-Ts, peptidyl-tRNA hydrolase, DnaK), membrane functions (OmpA-like protein and ABC transporter-related protein), and nucleotide metabolism (HIT family hydrolase). Together, these survivability and biochemical parameters support the hypothesis that oxidative tolerance and the related biochemical features are the measurable phenotypes or outcomes for microbial survival in the spacecraft assembly facilities, where the low-humidity (desiccation) and clean (low-nutrient) conditions may serve as selective pressures. Hence, the spacecraft-associated Acinetobacter, due to the conferred oxidative tolerances, may ultimately hinder efforts to reduce spacecraft bioburden when using chemical sterilants, thus suggesting that non-spore-forming bacteria may need to be included in the bioburden accounting for future life-detection missions.

Elimination of hydrogen peroxide by Haemophilus somnus, a catalase-negative pathogen of cattle.

OpenAIRE

Sample, A K; Czuprynski, C J

1991-01-01

Haemophilus somnus is a catalase-negative, gram-negative pathogen of cattle which is refractory to killing by bovine neutrophils. In this report, we showed that H. somnus rapidly inhibited Luminol-dependent chemiluminescence of bovine neutrophils costimulated with opsonized zymosan or phorbol myristate acetate. We have postulated that this inhibition resulted in part from H. somnus preventing the accumulation of hydrogen peroxide (H2O2) during the oxidative burst. In support of this hypothesi...

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

Institute of Scientific and Technical Information of China (English)

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.

Thermometric titration of cadmium with sodium diethyldithiocarbamate, with oxidation by hydrogen peroxide as indicator reaction.

Science.gov (United States)

Hattori, T; Yoshida, H

1987-08-01

A new method of end-point indication is described for thermometric titration of cadmium with sodium diethyldithiocarbamate (DDTC). It is based on the redox reaction between hydrogen peroxide added to the system before titration, and the first excess of DDTC. Amounts of cadmium in the range 10-50 mumoles are titrated within 1% error.

Determination of active oxygen content in rare earth peroxides

International Nuclear Information System (INIS)

Queiroz, Carlos A.S.; Abrao, Alcidio

1993-01-01

The content of active oxygen in rare earth peroxides have been determined after the dissolution of the samples with hydrocloridic acid in the presence of potassium iodide. The free generated iodine is titrated with sodium thiosulfate using starch as indicator. The oxidation of iodide to the free iodine indicates the presence of a higher valence state rare earth oxide, until now specifically recognized for the oxides of cerium (Ce O 2 ), praseodymium (Pr 6 O 1 1) and terbium (TB 4 O 7 ). recently the authors synthesized a new series of rare earth compounds, the peroxides. These new compounds were prepared by precipitating the rare earth elements complexed with carbonate ion by addition of hydrogen peroxide. the authors demonstrated that all rare earth elements, once solubilized by complexing with carbonate ion, are quantitatively precipitated as peroxide by addition of hydrogen peroxide. (author)

Peroxidized mineral oil increases the oxidant status of culture media and inhibits in vitro porcine embryo development.

Science.gov (United States)

Martinez, C A; Nohalez, A; Ceron, J J; Rubio, C P; Roca, J; Cuello, C; Rodriguez-Martinez, H; Martinez, E A; Gil, M A

2017-11-01

The use of oils with undetected alterations is a long-recognized problem for in vitro embryo production systems. Since peroxides in oils have been associated with reduced embryo production outcomes, our goals were (1) to evaluate the effects of a batch of mineral oil (MO) that was suspected to be altered on the in vitro production of pig embryos and (2) to determine oil peroxide values throughout culture and the transfer of oxidant agents from oil to culture media. Sunflower oil, which has a completely different chemical composition than MO but a higher oxidative status, and unaltered MO were used as controls. Oocyte maturation, fertilization and embryo development were affected differently depending on the oil overlay used. While the suspected MO was not able to sustain in vitro maturation and fertilization, the oocytes incubated in the presence of sunflower oil were matured and fertilized similarly to those of the unaltered MO group. Moreover, the cleavage rate of presumed zygotes cultured under the suspected MO was severely reduced compared with those cultured under the other oils, and none of the cleaved embryos developed to the blastocyst stage. Although the cleavage rates in the sunflower oil and unaltered MO groups were similar, embryos cultured under sunflower oil also failed to develop to the blastocyst stage. Our results revealed that the suspected MO and sunflower oil had similar levels of peroxides and that these levels were much higher than those of the unaltered MO. The total oxidant status was higher in media incubated under peroxidized oils than in fresh media or media incubated without an oil overlay or under unaltered MO, indicating that oxidant agents were transferred to the incubation media. However, unlike the sunflower oil group, the culture media incubated under the suspected MO had high levels of total oxidant status and low levels of hydrogen peroxide and reactive oxygen species, suggesting the presence of other unknown oxidant agents in

Hydrogen peroxide treatment on ZnO substrates to investigate the characteristics of Pt and Pt oxide Schottky contacts

International Nuclear Information System (INIS)

Tsai, Chia-Hung; Hung, Chen-I; Yang, Cheng-Fu; Houng, Mau-Phon

2010-01-01

We utilize hydrogen peroxide (H 2 O 2 ) treatment on (0 0 0 1) ZnO substrates to investigate the characteristics of Pt and Pt oxide Schottky contacts (SCs). X-ray rocking curves show the mosaicity structure becomes larger after H 2 O 2 treatment. Photoluminescence (PL) spectra show the yellow-orange emission peaking at ∼576-580 nm with respect to deep level of oxygen interstitials introduced by H 2 O 2 treatment. The threshold formation of ZnO 2 resistive layer on H 2 O 2 -treated ZnO for 45 min is observed from grazing-incidence X-ray diffraction. The better electrical characteristic is performed by Pt oxide SC with the larger barrier height (1.09 eV) and the lower leakage current (9.52 x 10 -11 A/cm 2 at -2 V) than Pt SC on the H 2 O 2 -treated ZnO for 60 min. X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometer (SIMS) examinations indicate the promoted interface oxide bonding and Zn outdiffusion for Pt oxide contact, different from Pt contact. Based on current-voltage, capacitance-voltage, X-ray diffraction, PL spectra, XPS, and SIMS results, the possible mechanism for effective rectifying characteristic and enhanced Schottky fbehavior is given.

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

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Ying Zhang

2017-05-01

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

Evaluation of Biofuel Cells with Hemoglobin as Cathodic Electrocatalysts for Hydrogen Peroxide Reduction on Bare Indium-Tin-Oxide Electrodes

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Yusuke Ayato

2013-12-01

Full Text Available A biofuel cell (BFC cathode has been developed based on direct electron transfer (DET of hemoglobin (Hb molecules with an indium-tin-oxide (ITO electrode and their electrocatalysis for reduction of hydrogen peroxide (H2O2. In this study, the ITO-coated glass plates or porous glasses were prepared by using a chemical vapor deposition (CVD method and examined the electrochemical characteristics of the formed ITO in pH 7.4 of phosphate buffered saline (PBS solutions containing and not containing Hb. In half-cell measurements, the reduction current of H2O2 due to the electrocatalytic activity of Hb increased with decreasing electrode potential from around 0.1 V versus Ag|AgCl|KCl(satd. in the PBS solution. The practical open-circuit voltage (OCV on BFCs utilizing H2O2 reduction at the Hb-ITO cathode with a hydrogen (H2 oxidation anode at a platinum (Pt electrode was expected to be at least 0.74 V from the theoretical H2 oxidation potential of −0.64 V versus Ag|AgCl|KCl(satd. in pH 7.4. The assembled single cell using the ITO-coated glass plate showed the OCV of 0.72 V and the maximum power density of 3.1 µW cm−2. The maximum power per single cell was recorded at 21.5 µW by using the ITO-coated porous glass.

Bruton's tyrosine kinase is essential for hydrogen peroxide-induced calcium signaling.

Science.gov (United States)

Qin, S; Chock, P B

2001-07-10

Using Btk-deficient DT40 cells and the transfectants expressing wild-type Btk or Btk mutants in either kinase (Arg(525) to Gln), Src homology 2 (SH2, Arg(307) to Ala), or pleckstrin homology (PH, Arg(28) to Cys) domains, we investigated the roles and structure-function relationships of Btk in hydrogen peroxide-induced calcium mobilization. Our genetic evidence showed that Btk deficiency resulted in a significant reduction in hydrogen peroxide-induced calcium response. This impaired calcium signaling is correlated with the complete elimination of IP3 production and the significantly reduced tyrosine phosphorylation of PLCgamma2 in Btk-deficient DT40 cells. All of these defects were fully restored by the expression of wild-type Btk in Btk-deficient DT40 cells. The data from the point mutation study revealed that a defect at any one of the three functional domains would prevent a full recovery of Btk-mediated hydrogen peroxide-induced intracellular calcium mobilization. However, mutation at either the SH2 or PH domain did not affect the hydrogen peroxide-induced activation of Btk. Mutation at the SH2 domain abrogates both IP3 generation and calcium release, while the mutant with the nonfunctional PH domain can partially activate PLCgamma2 and catalyze IP3 production but fails to produce significant calcium mobilization. Thus, these observations suggest that Btk-dependent tyrosine phosphorylation of PLCgamma2 is required but not sufficient for hydrogen peroxide-induced calcium mobilization. Furthermore, hydrogen peroxide stimulates a Syk-, but not Btk-, dependent tyrosine phosphorylation of B cell linker protein BLNK. The overall results, together with those reported earlier [Qin et al. (2000) Proc. Natl. Acad. Sci. U.S.A. 97, 7118], are consistent with the notion that functional SH2 and PH domains are required for Btk to form a complex with PLCgamma2 through BLNK in order to position the Btk, PLCgamma2, and phosphatidylinositol 4,5-bisphosphate in close proximity for

Dioscorin pre-treatment protects A549 human airway epithelial cells from hydrogen peroxide-induced oxidative stress.

Science.gov (United States)

Hsu, Jeng-Yuan; Chu, Jao-Jia; Chou, Ming-Chih; Chen, Ya-Wen

2013-10-01

Hydrogen peroxide (H(2)O(2)) is a highly reactive oxygen species involved in lung and bronchial epithelium injury. Increased H(2)O(2) levels have been reported in expired breath condensates of patients with inflammatory airway diseases such as chronic obstructive pulmonary disease. Protecting airway epithelial cells from oxidative stress is an important task in the prevention and management of airway diseases. Previous studies demonstrate that yam (Dioscorea batatas Decne) has antioxidant and anti-trypsin activities. This study evaluated the validity of dioscorin in vitro. The results showed that dioscorin attenuated the alteration of H(2)O(2) on G2/M cell cycle arrest. This might be associated with the activation of IκB and subsequent inactivation of NF-κB. Furthermore, dioscorin suppressed IL-8 secretion and reduced changes of adhesion molecule expressions in H(2)O(2)-injured A549 cells. These results help in understanding the potential of traditional Chinese herbal medicine as treatment for airway inflammatory diseases.

Hydrogen peroxide coordination to cobalt(II) facilitated by second-sphere hydrogen bonding

Czech Academy of Sciences Publication Activity Database

Wallen, C.M.; Palatinus, Lukáš; Bacsa, J.; Scarborough, C.C.

2016-01-01

Roč. 55, č. 39 (2016), s. 11902-11906 ISSN 0044-8249 Institutional support: RVO:68378271 Keywords : cobalt * hydrogen bonds * peroxides * peroxido ligands * second-sphere interactions Subject RIV: CC - Organic Chemistry

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

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Siroos Shojaei

2017-04-01

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

Reaction mechanisms and evaluation of effective process operation for catalytic oxidation and coagulation by ferrous solution and hydrogen peroxide

Energy Technology Data Exchange (ETDEWEB)

Lee, S.H.; Moon, H.J.; Kim, Y.M. [Dept. of Environmental Engineering, Sangmyung Univ., Cheonan (Korea); Bae, W.K. [Dept. of Civil and Environmental Engineering, Hanyang Univ., Ansan, Kyounggi (Korea)

2003-07-01

This research was carried out to evaluate the removal efficiencies of COD{sub cr} and colour for the dyeing wastewater by ferrous solution and the different dosage of H{sub 2}O{sub 2} in Fenton process. In the case of H{sub 2}O{sub 2} divided dosage, 7:3 was more effective than 3:7 to remove COD{sub cr} and colour. The results showed that COD was mainly removed by Fenton coagulation, where the ferric ions are formed in the initial step of Fenton reaction. On the other hand colour was removed by Fenton oxidation rather than Fenton coagulation. This paper also aims at pursuing to investigate the effective removal mechanisms using ferrous ion coagulation, ferric ion coagulation and Fenton oxidation process. The removal mechanism of COD{sub cr} and colour was mainly coagulation by ferrous ion, ferric ion and Fenton oxidation. The removal efficiencies were dependent on the ferric ion amount at the beginning of the reaction. However the final removal efficiency of COD and colour was in the order of Fenton oxidation, ferric ion coagulation and ferrous ion coagulation. The reason of the highest removal efficiency by Fenton oxidation can be explained by the chain reactions with ferrous solution, ferric ion and hydrogen peroxide. (orig.)

Thermocatalytic Behavior of Manganese (IV Oxide as Nanoporous Material on the Dissociation of a Gas Mixture Containing Hydrogen Peroxide

Directory of Open Access Journals (Sweden)

Zaid B. Jildeh

2018-04-01

Full Text Available In this article, we present an overview on the thermocatalytic reaction of hydrogen peroxide (H 2 O 2 gas on a manganese (IV oxide (MnO 2 catalytic structure. The principle of operation and manufacturing techniques are introduced for a calorimetric H 2 O 2 gas sensor based on porous MnO 2 . Results from surface analyses by X-ray photoelectron spectroscopy (XPS and scanning electron microscopy (SEM of the catalytic material provide indication of the H 2 O 2 dissociation reaction schemes. The correlation between theory and the experiments is documented in numerical models of the catalytic reaction. The aim of the numerical models is to provide further information on the reaction kinetics and performance enhancement of the porous MnO 2 catalyst.

Thermocatalytic Behavior of Manganese (IV) Oxide as Nanoporous Material on the Dissociation of a Gas Mixture Containing Hydrogen Peroxide.

Science.gov (United States)

Jildeh, Zaid B; Oberländer, Jan; Kirchner, Patrick; Wagner, Patrick H; Schöning, Michael J

2018-04-21

In this article, we present an overview on the thermocatalytic reaction of hydrogen peroxide (H 2 O 2 ) gas on a manganese (IV) oxide (MnO 2 ) catalytic structure. The principle of operation and manufacturing techniques are introduced for a calorimetric H 2 O 2 gas sensor based on porous MnO 2 . Results from surface analyses by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) of the catalytic material provide indication of the H 2 O 2 dissociation reaction schemes. The correlation between theory and the experiments is documented in numerical models of the catalytic reaction. The aim of the numerical models is to provide further information on the reaction kinetics and performance enhancement of the porous MnO 2 catalyst.

A Self-Supported Direct Borohydride-Hydrogen Peroxide Fuel Cell System

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Ashok K. Shukla

2009-04-01

Full Text Available A self-supported direct borohydride-hydrogen peroxide fuel cell system with internal manifolds and an auxiliary control unit is reported. The system, while operating under ambient conditions, delivers a peak power of 40 W with about 2 W to run the auxiliary control unit. A critical cause and effect analysis, on the data for single cells and stack, suggests the optimum concentrations of fuel and oxidant to be 8 wt. % NaBH4 and 2 M H2O2, respectively in extending the operating time of the system. Such a fuel cell system is ideally suited for submersible and aerospace applications where anaerobic conditions prevail.

A kinetic and ESR investigation of iron(II) oxalate oxidation by hydrogen peroxide and dioxygen as a source of hydroxyl radicals

DEFF Research Database (Denmark)

Park, J S; Wood, P M; Davies, Michael Jonathan

1997-01-01

The reaction of Fe(II) oxalate with hydrogen peroxide and dioxygen was studied for oxalate concentrations up to 20 mM and pH 2-5, under which conditions mono- and bis-oxalate complexes (Fe[II](ox) and Fe[II](ox)2[2-]) and uncomplexed Fe2+ must be considered. The reaction of Fe(II) oxalate...... with hydrogen peroxide (Fe2+ + H2O2 --> Fe3+ + .OH + OH-) was monitored in continuous flow by ESR with t-butanol as a radical trap. The reaction is much faster than for uncomplexed Fe2+ and a rate constant, k = 1 x 10(4) M(-1) s(-1) is deduced for Fe(II)(ox). The reaction of Fe(II) oxalate with dioxygen...... by oxalate. Further ESR studies with DMPO as spin trap reveal that reaction of Fe(II) oxalate with hydrogen peroxide can also lead to formation of the carboxylate radical anion (CO2-), an assignment confirmed by photolysis of Fe(II) oxalate in the presence of DMPO....

The hydrogen peroxide impact on larval settlement and metamorphosis of abalone Haliotis diversicolor supertexta

Science.gov (United States)

Zhang, Xiangjing; Yang, Zhihui; Cai, Zhonghua

2008-08-01

Abalone Haliotis diversicolor supertexta is an important economic mollusk. The settlement and metamorphosis are two critical stages during its development period, which has direct influence on abalone survival and production. The influence of reactive oxygen species (hydrogen peroxide) on abalone embryo and juvenile development were examined in this study. Larvae of Haliotis diversicolor supertexta were induced to settlement and metamorphose by exposure to seawater supplemented with hydrogen peroxide. They had the best performance at 800 μmol/L. The concentration of 1 000 μmol/L or higher was toxic to the larvae, as the larvae could settle down only at benthic diatom plates without complete metamorphosis. In addition, H2O2 adding time was critical to the larval performance. 24h after two-day post-fertilization was proved to be the optimal adding time. In this paper, two action mechanisms of hydrogen peroxide are discussed: (1) hydrogen peroxide has direct toxicity to ciliated cells, thus cause apoptosis; (2) hydrogen peroxide, as a product from catecholamines’ autoxidation process in vivo, can reverse this process to produce neuro-transmitters to induce abalone metamorphosis.

Surface Passivation of CdZnTe Detector by Hydrogen Peroxide Solution Etching

Science.gov (United States)

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

1998-01-01

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

A novel sodium iodide and ammonium molybdate co-catalytic system for the efficient synthesis of 2-benzimidazoles using hydrogen peroxide under ultrasound irradiation.

Science.gov (United States)

Bai, Guo-Yi; Lan, Xing-Wang; Chen, Guo-Feng; Liu, Xiao-Fang; Li, Tian-Yu; Shi, Ling-Juan

2014-03-01

The reaction of aldehydes and o-phenylenediamine for the preparation of 2-benzimidazoles has been studied using hydrogen peroxide as an oxidant under ultrasound irradiation at room temperature in this paper. The combination of substoichiometric sodium iodide and ammonium molybdate as co-catalysts, together with using small amounts of hydrogen peroxide, makes this transformation very efficient and attractive under ultrasound. Thus, a mild, green and efficient method is established to carry out this reaction in high yield. Copyright © 2013 Elsevier B.V. All rights reserved.

Linarin isolated from Buddleja officinalis prevents hydrogen peroxide-induced dysfunction in osteoblastic MC3T3-E1 cells.

Science.gov (United States)

Kim, Young Ho; Lee, Young Soon; Choi, Eun Mi

2011-01-01

The flowers and leaves buds of Buddleja officinalis MAXIM (Buddlejaceae) are used to treat eye troubles, hernia, gonorrhea and liver troubles in Asia. To elucidate the protective effects of linarin isolated from B. officinalis on the response of osteoblast to oxidative stress, osteoblastic MC3T3-E1 cells were pre-incubated with linarin for 1h before treatment with 0.3mM H(2)O(2) for 48h, and markers of osteoblast function and oxidative damage were examined. Linarin significantly (P<0.05) increased cell survival, alkaline phosphatase (ALP) activity, collagen content, calcium deposition, and osteocalcin secretion and decreased the production of receptor activator of nuclear factor-kB ligand (RANKL), protein carbonyl (PCO), and malondialdehyde (MDA) of osteoblastic MC3T3-E1 cells in the presence of hydrogen peroxide. These results demonstrate that linarin can protect osteoblasts against hydrogen peroxide-induced osteoblastic dysfunction and may exert anti-resorptive actions, at least in part, via the reduction of RANKL and oxidative damage. 2011 Elsevier Inc. All rights reserved.

Disinfection of wastewater by hydrogen peroxide or peracetic acid: development of procedures for measurement of residual disinfectant and application to a physicochemically treated municipal effluent.

Science.gov (United States)

Wagner, Monika; Brumelis, Daina; Gehr, Ronald

2002-01-01

The Montreal Urban Community Wastewater Treatment Plant (MUCWTP) located in Montreal. Quebec, Canada, uses physicochemical treatment processes prior to discharging wastewater into the St. Lawrence River via an outfall tunnel of 2 hours retention time. Although chlorination facilities exist, they are not being used, and the MUCWTP is seeking alternative methods for disinfection to achieve a 2- to 3-log fecal coliform reduction. Liquid chemical disinfectants were attractive options because of their low capital costs. This led to an investigation of the feasibility of using hydrogen peroxide or peracetic acid. A method for measuring peroxycompounds (hydrogen peroxide or peracetic acid plus hydrogen peroxide) was developed using the peroxidase-based oxidation of 2,2'-azino-bis(3-ethylbenz-thiazoline-6-sulfuric acid) diammonium salt (ABTS) with hydrogen peroxide. The validity of the method was confirmed using effluent from the MUCWTP. Recovery was higher than 90% for peracetic acid levels as low as 1.0 mg/L. Quenching of hydrogen peroxide was achieved with 50-mg/L catalase; quenching of peracetic acid was achieved with 100 mg/L of sodium thiosulfate, followed by 50 mg/L of catalase. Batch disinfection tests were conducted on MUCWTP effluent. Hydrogen peroxide and peracetic acid in wastewater over time could be modeled as a second-order decay, with the decay "constant" being a function of the initial concentration of peroxycompounds. This function was the same for both hydrogen peroxide and peracetic acid, possibly indicating similar decomposition pathways in wastewater matrices. Disinfection was modeled using a modified Hom equation. Required doses of hydrogen peroxide to reach the target fecal coliform levels ranged from 106 to 285 mg/L, with the higher doses occurring when ferric chloride instead of alum was used as the coagulant. Hence, hydrogen peroxide was infeasible as a disinfectant for this application. On the other hand, the peracetic acid dose needed to

The Correlation Between Urinary 8-Iso-Prostaglandin F2α and Hydrogen Peroxide Toward Renal Function in T2DM Patients Consuming Sulfonylurea and Combination of Metformin-Sulfonylurea.

Science.gov (United States)

Sauriasari, Rani; Wulandari, Fitri; Nurifahmi, Rahmaningtyas; Sekar, Andisyah P; Susilo, Veronika Y

2018-01-01

Renal dysfunction is a common complication in type 2 diabetes mellitus patients associated with oxidative damage which could be characterized by 8-iso-prostaglandin F2α and hydrogen peroxide level as oxidative stress markers. The aim of our study is to determine if there is a difference in 8-iso-prostaglandin F2α and hydrogen peroxide levels between sulfonylurea and combination of metformin-sulfonylurea in diabetic patients. We also wanted to determine if these oxidative stress markers correlate with the estimated Glomerular Filtration Rate (eGFR). We conducted a cross-sectional study with inclusion of 55 patients with type 2 diabetes mellitus in Dr. Sitanala Tangerang Hospital, Indonesia with purposive sampling. The value of eGFR was obtained by serum creatinine levels, while the level of 8-iso-prostaglandin F2α was measured by ELISA and urinary hydrogen peroxide using FOX-1 (Ferrous Ion Oxidation Xylenol Orange 1). There was no difference in 8-iso-prostaglandin F2α and hydrogen peroxide level between the two groups (p=0.088 and p=0.848). Moreover, there was no difference in eGFR values between the two groups, measured by Cockroft-Gault, MDRD, and CKD-EPI. 8-iso-prostaglandin F2α (n=55) was positively correlated with eGFR based on Cockroft-Gault (r=0.382; p=0.009), whereas urinary hydrogen peroxide (n=47) also generate significant positive correlation with eGFR based on the MDRD equation (r=0.326; p=0.021). Linear regression analysis showed that 8-iso-prostaglandin F2α is the most predictive factor and the only significant factor for eGFR in Cockroft-Gault, MDRD and also CKDEPI, even after controlled by gender, age, BMI, HbA1c, systole, and H2O2. The two treatments did not have any significant differences in antioxidant activity. However, an increase of urinary 8-iso-prostaglandin F2. and hydrogen peroxide which correlates with eGFR in the total sample may play a significant role in the pathophysiology of diabetic nephropathy. Copyright© Bentham Science

Hydrogen peroxide and polyamines act as double edged swords in plant abiotic stress responses

Directory of Open Access Journals (Sweden)

Kamala Gupta

2016-09-01

Full Text Available The specific genetic changes through which plants adapt to the multitude of environmental stresses are possible because of the molecular regulations in the system. These intricate regulatory mechanisms once unveiled will surely raise interesting questions. Polyamines and hydrogen peroxide have been suggested to be important signalling molecules during biotic and abiotic stresses. Hydrogen peroxide plays a versatile role from orchestrating physiological processes to stress response. It helps to achieve acclimatization and tolerance to stress by coordinating intra-cellular and systemic signalling systems. Polyamines, on the other hand, are low molecular weight polycationic aliphatic amines, which have been implicated in various stress responses. It is quite interesting to note that both hydrogen peroxide and polyamines have a fine line of inter-relation between them since the catabolic pathways of the latter releases hydrogen peroxide. In this review we have tried to illustrate the roles and their multifaceted functions of these two important signalling molecules based on current literature. This review also highlights the fact that over accumulation of hydrogen peroxide and polyamines can be detrimental for plant cells leading to toxicity and pre-mature cell death.

Hydrogen Peroxide and Polyamines Act as Double Edged Swords in Plant Abiotic Stress Responses.

Science.gov (United States)

Gupta, Kamala; Sengupta, Atreyee; Chakraborty, Mayukh; Gupta, Bhaskar

2016-01-01

The specific genetic changes through which plants adapt to the multitude of environmental stresses are possible because of the molecular regulations in the system. These intricate regulatory mechanisms once unveiled will surely raise interesting questions. Polyamines and hydrogen peroxide have been suggested to be important signaling molecules during biotic and abiotic stresses. Hydrogen peroxide plays a versatile role from orchestrating physiological processes to stress response. It helps to achieve acclimatization and tolerance to stress by coordinating intra-cellular and systemic signaling systems. Polyamines, on the other hand, are low molecular weight polycationic aliphatic amines, which have been implicated in various stress responses. It is quite interesting to note that both hydrogen peroxide and polyamines have a fine line of inter-relation between them since the catabolic pathways of the latter releases hydrogen peroxide. In this review we have tried to illustrate the roles and their multifaceted functions of these two important signaling molecules based on current literature. This review also highlights the fact that over accumulation of hydrogen peroxide and polyamines can be detrimental for plant cells leading to toxicity and pre-mature cell death.

Cardiac Response to Chronic Intermittent Hypoxia with a Transition from Adaptation to Maladaptation: The Role of Hydrogen Peroxide

Directory of Open Access Journals (Sweden)

Xia Yin

2012-01-01

Full Text Available Obstructive sleep apnea (OSA is a highly prevalent respiratory disorder of sleep, and associated with chronic intermittent hypoxia (CIH. Experimental evidence indicates that CIH is a unique physiological state with potentially “adaptive” and “maladaptive” consequences for cardio-respiratory homeostasis. CIH is also a critical element accounting for most of cardiovascular complications of OSA. Cardiac response to CIH is time-dependent, showing a transition from cardiac compensative (such as hypertrophy to decompensating changes (such as failure. CIH-provoked mild and transient oxidative stress can induce adaptation, but severe and persistent oxidative stress may provoke maladaptation. Hydrogen peroxide as one of major reactive oxygen species plays an important role in the transition of adaptive to maladaptive response to OSA-associated CIH. This may account for the fact that although oxidative stress has been recognized as a driver of cardiac disease progression, clinical interventions with antioxidants have had little or no impact on heart disease and progression. Here we focus on the role of hydrogen peroxide in CIH and OSA, trying to outline the potential of antioxidative therapy in preventing CIH-induced cardiac damage.

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

Energy Technology Data Exchange (ETDEWEB)

Moreira, Ruda F.; Calazans, Fernanda S.; Miranda, Mauro S.; Santos, Ramon S.; Anjos, Marcelino J.; Assis, Joaquim T. [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil)

2013-07-01

Hydrogen Peroxide's a bleaching agent capable of oxidizing a wide range of colored organic, causing discoloration and hence bleaching of the substrate, but some authors related the occurrence of side effects related to bleaching of the tooth structure, such as changes in morphology superficial. It was used 6 bovine incisors, each tooth was initially evaluated six times in different areas to obtain the count of elements phosphorus and calcium using X-Ray Fluorescence. The teeth were randomly divided in two groups: both groups were submitted to bleaching in office with hydrogen peroxide 38%, once a week during three weeks. Group 1 was stored in distilled water and group 2 in artificial saliva, between the sessions. The measurements were repeated every seven days before the bleaching treatment. Besides that, changes in mineral levels were always assessed in the same area and using the same procedure. It was observed that the bleaching was not able to demineralize the tooth enamel studied. (author)

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

International Nuclear Information System (INIS)

Moreira, Ruda F.; Calazans, Fernanda S.; Miranda, Mauro S.; Santos, Ramon S.; Anjos, Marcelino J.; Assis, Joaquim T.

2013-01-01

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)

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

Science.gov (United States)

Loranger, E.; Charles, A.; Daneault, C.

2012-12-01

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.

Inorganic precursor peroxides for antifouling coatings

DEFF Research Database (Denmark)

Olsen, S.M.; Pedersen, L.T.; Hermann, M.H.

2009-01-01

Modern antifouling coatings are generally based on cuprous oxide (Cu2O) and organic biocides as active ingredients. Cu2O is prone to bioaccumulation, and should therefore be replaced by more environmentally benign compounds when technically possible. However, cuprous oxide does not only provide...... antifouling properties, it is also a vital ingredient for the antifouling coating to obtain its polishing and leaching mechanism. In this paper, peroxides of strontium, calcium, magnesium, and zinc are tested as pigments in antifouling coatings. The peroxides react with seawater to create hydrogen peroxide...... matrix provides antifouling properties exceeding those of a similar coating based entirely on zinc oxide....

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

Directory of Open Access Journals (Sweden)

Jirapa Chetsawang

2010-01-01

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

Synergism between hydrogen peroxide and seventeen acids against six bacterial strains.

Science.gov (United States)

Martin, H; Maris, P

2012-09-01

The objective of this study was to evaluate the bactericidal efficacy of hydrogen peroxide administered in combination with 17 mineral and organic acids authorized for use in the food industry. The assays were performed on a 96-well microplate using a microdilution technique based on the checkerboard titration method. The six selected strains were reference strains and strains representative of contaminating bacteria in the food industry. Each synergistic hydrogen peroxide/acid combination found after 5-min contact time at 20°C in distilled water was then tested in conditions simulating four different use conditions. Thirty-two combinations were synergistic in distilled water; twenty-five of these remained synergistic with one or more of the four mineral and organic interfering substances selected. Hydrogen peroxide/formic acid combination was synergistic for all six bacterial strains in distilled water and remained synergistic with interfering substances. Six other combinations maintained their synergistic effect in the presence of an organic load but only for one or two bacterial strains. Synergistic combinations of disinfectants were revealed, among them the promising hydrogen peroxide/formic acid combination. A rapid screening method was proposed and used to reveal the synergistic potential of disinfectant and/or sanitizer combinations. © 2012 ANSES Fougères Laboratory Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

Kinetic method of ruthenium ion traces determination, basing on the reaction of oxidation of direct blue 6B, by means of hydrogen peroxide

International Nuclear Information System (INIS)

Suwinska, T.; Gregorowicz, A.; Matysek-Majewska, D.

1980-01-01

A sensitive and selective method of determination of ruthenium ion traces (1.10 - 3 μg/cm 3 ) has been worked out. The method is based on oxidation of direct blue 6B by hydrogen peroxide under acidic conditions at pH = 0,8 - 1,2 in the presence of ruthenium ions as catalyst. The method has been applied for determination of ruthenium traces in Pt, PdCl 2 , PtCl 4 and RhCl 3 .n H 2 O. In these materials ruthenium has been determined within the range of 1,10 - 2 % - 5,10 - 4 %. (author)

Use of bovine catalase and manganese dioxide for elimination of hydrogen peroxide from partly oxidized aqueous solutions of aromatic molecules - Unexpected complications

Science.gov (United States)

Kovács, Krisztina; Sági, Gyuri; Takács, Erzsébet; Wojnárovits, László

2017-10-01

Being a toxic substance, hydrogen peroxide (H2O2) formed during application of advanced oxidation processes disturbs the biological assessment of the treated solutions. Therefore, its removal is necessary when the concentration exceeds the critical level relevant to the biological tests. In this study, H2O2 removal was tested using catalase enzyme or MnO2 as catalysts and the concentration changes were measured by the Cu(II)/phenanthroline method. MnO2 and Cu(II) were found to react not only with H2O2 but also with the partly oxidized intermediates formed in the hydroxyl radical induced degradation of aromatic antibiotic and pesticide compounds. Catalase proved to be a milder oxidant, it did not show significant effects on the composition of organic molecules. The Cu(II)/phenanthroline method gives the correct H2O2 concentration only in the absence of easily oxidizable compounds, e.g. certain phenol type molecules.

The development of 1,3-diphenylisobenzofuran as a highly selective probe for the detection and quantitative determination of hydrogen peroxide.

Science.gov (United States)

Żamojć, Krzysztof; Zdrowowicz, Magdalena; Rudnicki-Velasquez, Paweł Błażej; Krzymiński, Karol; Zaborowski, Bartłomiej; Niedziałkowski, Paweł; Jacewicz, Dagmara; Chmurzyński, Lech

2017-01-01

1,3-Diphenylisobenzofuran (DPBF) has been developed as a selective probe for the detection and quantitative determination of hydrogen peroxide in samples containing different reactive nitrogen and oxygen species (RNOS). DPBF is a fluorescent probe which, for almost 20 years, was believed to react in a highly specific manner toward some reactive oxygen species (ROS) such as singlet oxygen and hydroxy, alkyloxy or alkylperoxy radicals. Under the action of these individuals DPBF has been rapidly transformed to 1,2-dibenzoylbenzene (DBB). In order to check if DPBF can act as a unique indicator of the total amount of different RNOS, as well as oxidative stress caused by an overproduction of these individuals, a series of experiments was carried out, in which DPBF reacted with peroxynitrite anion, superoxide anion, hydrogen peroxide, hypochlorite anion, and anions commonly present under biological conditions, namely nitrite and nitrate. In all cases, except for hydrogen peroxide, the product of the reaction is DBB. Only under the action of H 2 O 2 9-hydroxyanthracen-10(9H)-one (oxanthrone) is formed. This product has been identified with the use of fluorescence spectroscopy, NMR spectroscopy, high performance liquid chromatography coupled with mass spectrometry, infrared spectroscopy, elemental analysis, and cyclic voltammetry (CV). A linear relationship was found between a decrease in the fluorescence intensity of DPBF and the concentration of hydrogen peroxide in the range of concentrations of 0.196-3.941 mM. DPBF responds to hydrogen peroxide in a very specific way with the limits of detection and quantitation of 88 and 122.8 μM, respectively. The kinetics of the reaction between DBBF and H 2 O 2 was also studied.

On the use of hydrogen peroxide as a masking agent for the determination of yttrium in uranium oxide - yttrium oxide mixture

International Nuclear Information System (INIS)

Rastogi, R.K.; Chaudhuri, N.K.; Rizvi, G.H.; Subramanian, M.S.

1985-01-01

The use of peroxide as a masking agent for uranium during the EDTA titration of yttrium in an yttrium-uranium mixture containing large amounts of uranium was investigated. High acetate ion concentration was necessary to keep the peroxy complex of uranium in solution during the titration. It was observed that uranium could be tolerated up to 500 mg in the determination of yttrium with 0.5 ml of 30% hydrogen peroxide in approx. 1M acetate medium. The precision and accuracy of the method based on 16 determinations of yttrium at 6-16 mg level in the presence of 300 mg uranium was found to be +-0.2%. (author)

Potentiometric Titration Method for Quantitative Determination of Hydrogen Peroxide

National Research Council Canada - National Science Library

Bessette, Russell R

2005-01-01

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

Power generation in fuel cells using liquid methanol and hydrogen peroxide

Science.gov (United States)

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

2002-01-01

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

Hydrogen peroxide production is affected by oxygen levels in mammalian cell culture.

Science.gov (United States)

Maddalena, Lucas A; Selim, Shehab M; Fonseca, Joao; Messner, Holt; McGowan, Shannon; Stuart, Jeffrey A

2017-11-04

Although oxygen levels in the extracellular space of most mammalian tissues are just a few percent, under standard cell culture conditions they are not regulated and are often substantially higher. Some cellular sources of reactive oxygen species, like NADPH oxidase 4, are sensitive to oxygen levels in the range between 'normal' physiological (typically 1-5%) and standard cell culture (up to 18%). Hydrogen peroxide in particular participates in signal transduction pathways via protein redox modifications, so the potential increase in its production under standard cell culture conditions is important to understand. We measured the rates of cellular hydrogen peroxide production in some common cell lines, including C2C12, PC-3, HeLa, SH-SY5Y, MCF-7, and mouse embryonic fibroblasts (MEFs) maintained at 18% or 5% oxygen. In all instances the rate of hydrogen peroxide production by these cells was significantly greater at 18% oxygen than at 5%. The increase in hydrogen peroxide production at higher oxygen levels was either abolished or substantially reduced by treatment with GKT 137831, a selective inhibitor of NADPH oxidase subunits 1 and 4. These data indicate that oxygen levels experienced by cells in culture influence hydrogen peroxide production via NADPH oxidase 1/4, highlighting the importance of regulating oxygen levels in culture near physiological values. However, we measured pericellular oxygen levels adjacent to cell monolayers under a variety of conditions and with different cell lines and found that, particularly when growing at 5% incubator oxygen levels, pericellular oxygen was often lower and variable. Together, these observations indicate the importance, and difficulty, of regulating oxygen levels experienced by cells in culture. Copyright © 2017 Elsevier Inc. All rights reserved.

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

International Nuclear Information System (INIS)

Lobyntseva, Elena; Kallio, Tanja; Alexeyeva, Nadezda; Tammeveski, Kaido; Kontturi, Kyoesti

2007-01-01

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 O 2 -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

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

Energy Technology Data Exchange (ETDEWEB)

Collins, Terrence J.; Horwitz, Colin

2004-11-12

A new, highly energy efficient approach for using catalytic oxidation chemistry in multiple fields of technology has been pursued. The new catalysts, called TAML® activators, catalyze the reactions of hydrogen peroxide and other oxidants for the exceptionally rapid decontamination of noninfectious simulants (B. atrophaeus) of anthrax spores, for the energy efficient decontamination of thiophosphate pesticides, for the facile, low temperature removal of color and organochlorines from pulp and paper mill effluent, for the bleaching of dyes from textile mill effluents, and for the removal of recalcitrant dibenzothiophene compounds from diesel and gasoline fuels. Highlights include the following: 1) A 7-log kill of Bacillus atrophaeus spores has been achieved unambiguously in water under ambient conditions within 15 minutes. 2) The rapid total degradation under ambient conditions of four thiophosphate pesticides and phosphonate degradation intermediates has been achieved on treatment with TAML/peroxide, opening up potential applications of the decontamination system for phosphonate structured chemical warfare agents, for inexpensive, easy to perform degradation of stored and aged pesticide stocks (especially in Africa and Asia), for remediation of polluted sites and water bodies, and for the destruction of chemical warfare agent stockpiles. 3) A mill trial conducted in a Pennsylvanian bleached kraft pulp mill has established that TAML catalyst injected into an alkaline peroxide bleach tower can significantly lower color from the effluent stream promising a new, more cost effective, energy-saving approach for color remediation adding further evidence of the value and diverse engineering capacity of the approach to other field trials conducted on effluent streams as they exit the bleach plant. 4) Dibenzothiophenes (DBTs), including 4,6-dimethyldibenzothiophene, the most recalcitrant sulfur compounds in diesel and gasoline, can be completely removed from model gasoline

EFFECT OF NATURAL IRON OXIDE, HYDROGEN PEROXIDE, AND OXALIC ACID ON PHOTOCHEMICAL DEGRADATION OF 2-CHLOROPHENOL

Directory of Open Access Journals (Sweden)

W REMACHE

2014-07-01

Full Text Available The voluntary or accidental release of chemical compounds in the environment is a major cause of pollution of natural waters. Most of chlorophenols are toxic and hardly biodegradable and are difficult to remove from the environment. Therefore, it is important to find innovative and economical methods for the safe and complete destruction. The objective of this work is to test the activity photocatalytic of natural iron oxide (NIO in the photodegradation of 2-chlorophenol (2-CP. The analysis chromatographic with HPLC of solutions exposed under UV irradiation revealed that the degradation of 2-CP was negligible under the condition of using only natural iron oxide. The effect of wavelength on photoreactivity of NIO was also investigated in this process: at high wavelength thus at low energy the efficiency of degradation is important. We have also investigated the activation of NIO by hydrogen peroxide and oxalic acid, The results showed that the photodegradation of 2-CP under UVA irradiation could be enhanced greatly in the presence of oxalate. 2-CP was completly removed after 240 minutes of irradiation when the concentration of oxalic acid is equal to 2.10-3 M. The use of 2.0 % of isopropanol as a scavenger confirmed the intervention of hydroxyl radicals in the photodegradation of 2-CP.

Development of biological and nonbiological explanations for the Viking label release data. [hydrogen peroxide theory

Science.gov (United States)

1980-01-01

The plausibility that hydrogen peroxide, widely distributed within the Mars surface material, was responsible for the evocative response obtained by the Viking Labeled Release (LR) experiment on Mars was investigated. Although a mixture of gamma Fe2O3 and silica sand stimulated the LR nutrient reaction with hydrogen peroxide and reduced the rate of hydrogen decomposition under various storage conditions, the Mars analog soil prepared by the Viking Inorganic Analysis Team to match the Mars analytical data does not cause such effects. Nor is adequate resistance to UV irradiation shown. On the basis of the results and consideration presented while the hydrogen peroxide theory remains the most, if not only, attractive chemical explanation of the LR data, it remains unconvincing on critical points. Until problems concerning the formation and stabilization of hydrogen peroxide on the surface of Mars can be overcome, adhere to the scientific evidence requires serious consideration of the biological theory.

Optical characteristics of particles produced using electroerosion dispersion of titanium in hydrogen peroxide

Science.gov (United States)

Pyachin, S. A.; Burkov, A. A.; Makarevich, K. S.; Zaitsev, A. V.; Karpovich, N. F.; Ermakov, M. A.

2016-07-01

Titanium oxide particles are produced using electric-discharge dispersion of titanium in aqueous solution of hydrogen peroxide. Electron vacuum microscopy, X-ray diffraction, and diffuse reflection spectroscopy are used to study the morphology, composition, and optical characteristics of the erosion particles. It has been demonstrated that the particles consist of titanium and titanium oxides with different valences. The edge of the optical absorption is located in the UV spectral range. The band gap is 3.35 eV for indirect transitions and 3.87 eV for direct allowed transitions. The band gap decreases due to the relatively long heating in air at a temperature of 480-550°C, so that powder oxide compositions can be obtained, the optical characteristics of which are similar to optical characteristics of anatase. The erosion products are completely oxidized to rutile after annealing in air at a temperature of 1000°C.

Sensitization of in vitro mammalian cells by nitrous oxide

International Nuclear Information System (INIS)

Ewing, D.

1984-01-01

Powers and his colleagues showed almost ten years ago that sensitization by nitrous oxide required two radiolytic products: OH radicals and hydrogen peroxide. That observation with bacterial spores has been confirmed and extended with spores and several strains of bacteria. OH must be present to form hydrogen peroxide, but, in addition, OH must also be present with the hydrogen peroxide for damage to occur. (Reagent hydrogen peroxide, except at very high concentrations, will not sensitize unless OH radicals are present.) The authors have now tested nitrous oxide with two Chinese hamster cell lines, V79 and CHO. The responses in nitrogen and nitrous oxide are the same for each. The authors have tentatively concluded that insufficient hydrogen peroxide is formed in the cells' suspending fluid for damage from nitrous oxide to occur. Several results support this conclusion: reagent hydrogen peroxide is a potent sensitizer of either cell line tested in nitrogen or nitrous oxide and an assay for radiolytic hydrogen peroxide confirms that only minimal levels are formed at the doses used in these survival curves. The authors also present results of other tests to further complement work with procaryotic cells

Efficacy of Mouthwashes Containing Hydrogen Peroxide on Tooth Whitening

OpenAIRE

Karadas, Muhammet; Hatipoglu, Omer

2015-01-01

The aim of this study was to analyze the efficacy of mouthwashes containing hydrogen peroxide compared with 10% carbamide peroxide (CP) gel. Fifty enamel-dentin samples were obtained from bovine incisors and then stained in a tea solution. The stained samples were randomly divided into five groups according to the whitening product applied (n = 10): AS: no whitening (negative control), with the samples stored in artificial saliva; CR: Crest 3D White mouthwash; LS: Listerine Whitening mouthwas...

Electrochemical behaviour of platinum in hydrogen peroxide solution (1963); Comportement electrochimique du platine en solution d'eau oxygene (1963)

Energy Technology Data Exchange (ETDEWEB)

Prost, G H [Commisariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

1963-06-15

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) [French] La stabilite relative de l'eau oxygenee en solution aqueuse a 25 deg. C permet d'envisager theoriquement son dosage par amperometrie, en utilisant soit sa reduction cathodique, soit son oxydation anodique. La reduction cathodique ne donne lieu a une vague sur electrode de platine qu'en presence d'oxygene dissous. Il n'est donc pas utilisable pour un dosage. L'oxydation anodique sur platine donne une vague theoriquement utilisable mais s'accompagne d'une passivation du platine. Le processus de la passivation est etudie au moyen des courbes potentiocinetiques, potentiostatiques, intensiostatiques et par une mesure des variations de pH au voisinage de l'anode. On propose un mecanisme de passivation en tenant compte du role activant de l'eau oxygenee. Cette passivation interdit toute application analytique de la reaction d'oxydation de l'eau oxygenee. (auteur)

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

Science.gov (United States)

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%. Copyright © 2014 Elsevier B.V. All rights reserved.

Comparison of sensitivity of repair-proficient and repair-deficient strains of Bacillus subtilis to ultraviolet irradiation and hydrogen peroxide

International Nuclear Information System (INIS)

Bayliss, C.E.; Shah, J.; Waites, W.M.

1982-01-01

Dormant bacterial spores are very resistant to irradiation with ultraviolet (UV) light. The authors have shown that simultaneous treatment with far-UV (254 nm) and hydrogen peroxide in a kill up to 2000-fold greater than that produced by irradiation either alone or followed by treatment with hydrogen peroxide. UV irradiation of hydrogen peroxide produces free hydroxyl radicals which are particularly lethal to microorganisms but free radical quenchers fail to protect spores against simultaneous UV and hydrogen peroxide. It is possible, therefore, that another mechanism is responsible for this synergistic killing. In this study the resistance was examined to simultaneous treatment with UV and hydrogen peroxide of a mutant of Bacillus subtilis which forms UV-sensitive spores. (Auth.)

Determination of peracetic acid and hydrogen peroxide in the mixture

Directory of Open Access Journals (Sweden)

Bodiroga Milanka

2002-01-01

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

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

International Nuclear Information System (INIS)

Clark, Catherine D.; Bruyn, Warren de; Jones, Joshua G.

2014-01-01

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 (H 2 O 2 ) 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 H 2 O 2 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 (Θ app ; 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

Organic hydrogen peroxide-driven low charge potentials for high-performance lithium-oxygen batteries with carbon cathodes

Science.gov (United States)

Wu, Shichao; Qiao, Yu; Yang, Sixie; Ishida, Masayoshi; He, Ping; Zhou, Haoshen

2017-06-01

Reducing the high charge potential is a crucial concern in advancing the performance of lithium-oxygen batteries. Here, for water-containing lithium-oxygen batteries with lithium hydroxide products, we find that a hydrogen peroxide aqueous solution added in the electrolyte can effectively promote the decomposition of lithium hydroxide compounds at the ultralow charge potential on a catalyst-free Ketjen Black-based cathode. Furthermore, for non-aqueous lithium-oxygen batteries with lithium peroxide products, we introduce a urea hydrogen peroxide, chelating hydrogen peroxide without any water in the organic, as an electrolyte additive in lithium-oxygen batteries with a lithium metal anode and succeed in the realization of the low charge potential of ~3.26 V, which is among the best levels reported. In addition, the undesired water generally accompanying hydrogen peroxide solutions is circumvented to protect the lithium metal anode and ensure good battery cycling stability. Our results should provide illuminating insights into approaches to enhancing lithium-oxygen batteries.

Spectrophotometric determination of hydrogen peroxide with osmium(VIII) and m-carboxyphenylfluorone.

Science.gov (United States)

Hoshino, Mitsuru; Kamino, Shinichiro; Doi, Mitsunobu; Takada, Shingo; Mitani, Shota; Yanagihara, Rika; Asano, Mamiko; Yamaguchi, Takako; Fujita, Yoshikazu

2014-01-03

Spectrophotometric determination of hydrogen peroxide was accomplished with osmium(VIII) and m-carboxyphenylfluorone (MCPF) in the presence of cetyltrimethylammonium chloride (CTAC). In the determination of hydrogen peroxide based on the fading of the color of osmium(VIII)-MCPF complex, Beer's law was obeyed in the range 20-406 ng mL(-1), with an effective molar absorption coefficient (at 580 nm) of 5.21×10(4) L mol(-1) cm(-1) and a relative standard deviation of 0.33% (n=6). Further, we performed the characterization of MCPF and obtained the crystal structure. Copyright © 2013 Elsevier B.V. All rights reserved.

Quantifying intracellular hydrogen peroxide perturbations in terms of concentration

Directory of Open Access Journals (Sweden)

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.

Evaluation of the toxicity and efficacy of hydrogen peroxide treatments on eggs of warm and cool water fishes

Science.gov (United States)

Rach, J.J.; Gaikowski, M.P.; Howe, G.E.; Schreier, Theresa M.

1998-01-01

The use of hydrogen peroxide in aquaculture is growing and there is a need to develop fundamental guidelines to effectively treat diseased fish. The safety (toxicity) of hydrogen peroxide treatments was determined on eggs of representative warm- and coolwater fish species. Eggs of northern pike (Esox lucius), walleye (Stizostedion vitreum), yellow perch (Pel ca flavescens), white sucker (Catostomus commersoni), lake sturgeon (Acipenser fulvescens), paddlefish (Polyodon spathula), common carp (Cyprinus carpio), and channel catfish (Ictalurus punctatus) were cultured in egg jars or aquaria. Treatments were initiated with non-eyed eggs and continued until all viable eggs had hatched. Eggs were treated daily for 15 min Monday through Friday with either 0, 500, 1000, 3000, or 6000 mu l l(-1) of hydrogen peroxide. For all species, the mean percent hatch was greater in eggs treated with 1000 mu l l(-1) hydrogen peroxide for 15 min than in the untreated controls. Common carp, lake sturgeon, and paddlefish were the least sensitive to hydrogen peroxide with percent hatch ranging from 40 to 48% in the 6000 mu l l(-1) hydrogen peroxide treatment. Fungal infections reduced or eliminated the hatch in most controls whereas nearly all treated eggs remained free of infection; hydrogen peroxide inhibited fungal infections on fish eggs. (C) 1998 Elsevier Science B.V. All rights reserved.

Simultaneous determination of superoxide and hydrogen peroxide in macrophage RAW 264.7 cell extracts by microchip electrophoresis with laser-induced fluorescence detection.

Science.gov (United States)

Li, Hongmin; Li, Qingling; Wang, Xu; Xu, Kehua; Chen, Zhenzhen; Gong, Xiaocong; Liu, Xin; Tong, Lili; Tang, Bo

2009-03-15

A method for the first time to simultaneously determine superoxide and hydrogen peroxide in macrophage RAW 264.7 cell extracts by microchip electrophoresis with laser-induced fluorescence detection (MCE-LIF) was developed. 2-Chloro-1,3-dibenzothiazolinecyclohexene (DBZTC) and bis(p-methylbenzenesulfonyl) dichlorofluorescein (FS), two probes that can be specifically derivatized by superoxide and hydrogen peroxide, respectively, were synthesized and used. Parameters influencing the derivatization and on-chip separation were optimized. With the use of a HEPES (20 mM, pH 7.4) running buffer, a 50 mm long separation channel, and a separation voltage of 1800 V, baseline separation was achieved within 48 s for the two derivatization products, DBZTC-oxide (DBO) and 2,7-dichlorofluorescein (DCF). The linearity ranges of the method were 0.08-5.0 and 0.02-5.0 microM with detection limits (signal-to-noise ratio = 3) of 10 nM (1.36 amol) and 5.6 nM (0.76 amol) for superoxide and hydrogen peroxide, respectively. The relative standard deviations (RSDs) of migration time and peak area were less than 2.0% and 5.0%, respectively. The recoveries of the cell extract samples spiked with 1.0 microM standard solutions were 96.1% and 93.0% for superoxide and hydrogen peroxide, respectively. With the use of this method, superoxide and hydrogen peroxide in phorbol myristate acetate (PMA)-stimulated macrophage RAW 264.7 cell extracts were found to be 0.78 and 1.14 microM, respectively. The method has paved a way for simultaneously determining two or more reactive oxygen species (ROS) in a biological system with high resolution.

Catalase-Aminotriazole Assay, an Invalid Method for Measurement of Hydrogen Peroxide Production by Wood Decay Fungi

OpenAIRE

Highley, Terry L.

1981-01-01

The catalase-aminotriazole assay for determination of hydrogen peroxide apparently cannot be used for measuring hydrogen peroxide production in crude preparations from wood decay fungi because of materials in the crude preparations that interfere with the test.

Vaporized Hydrogen Peroxide (VHP) Decontamination of VX, GD, and HD

National Research Council Canada - National Science Library

Wagner, George W; Sorrick, David C; Procell, Lawrence R; Hess, Zoe A; Brickhouse, Mark D; McVey, Iain F; Schwartz, Lewis I

2003-01-01

Vaporized Hydrogen Peroxide (VHP) has been utilized for more than a decade to sterilize clean rooms and pharmaceutical processing equipment and, quite recently, to decontaminate anthrax-ridden buildings...

Catalase induction in normal and tumorigenic mice using x-rays, clofibrate, ethanol, or hydrogen peroxide

International Nuclear Information System (INIS)

Alexander, L.; Oberley, L.

1985-01-01

The authors studied catalase induction in normal male Swiss mice as well as in male mice harboring H-6 hepatomas. The induction patterns many suggest reasons why tumor cells have lower catalase activity than normal cells. X-rays, hydrogen peroxide, ethanol, and clofibrate were used as inducing agents. X-rays interact with tissue and cause free radical formation. This results in an increase in hydrogen peroxide concentration, which ought to induce catalase. Oral administration of hydrogen peroxide should induce catalase similarly. Ethanol can be a substrate for catalase, forming acetalehyde; and as such may induce catalase. Ethanol can also restore inactive catalase compound II to useful catalase. Clofibrate is a hypolipidemic agent which induces catalase, most likely because of its ability to accelerate lipid breakdown, which raises peroxide concentration

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

International Nuclear Information System (INIS)

Kang Xiaobin; Pang Guangchang; Liang Xinyi; Wang Meng; Liu Jing; Zhu Weiming

2012-01-01

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.

Can hydrogen peroxide and quercetin improve production of ...

African Journals Online (AJOL)

The aim of the present work was to determine if hydrogen peroxide in combination with quercetin or indole butyric acid, can modify some characteristics related to rooting and development in cuttings of Eucalyptus grandis x Eucalyptus urophylla. Cuttings were periodically evaluated at 30, 60 and 90 days according to the ...

Diel cycles of hydrogen peroxide in marine bathing waters in Southern California, USA: In situ surf zone measurements

International Nuclear Information System (INIS)

Clark, Catherine D.; De Bruyn, Warren J.; Hirsch, Charlotte M.; Aiona, Paige

2010-01-01

Hydrogen peroxide is photochemically produced in natural waters. It has been implicated in the oxidative-induced mortality of fecal indicator bacteria (FIB), a microbial water quality measure. To assess levels and cycling of peroxide in beach waters monitored for FIB, diel studies were carried out in surf zone waters in July 2009 at Crystal Cove State Beach, Southern California, USA. Maximum concentrations of 160-200 nM were obtained within 1 h of solar noon. Levels dropped at night to 20-40 nM, consistent with photochemical production from sunlight. Day-time production and night-time dark loss rates averaged 16 ± 3 nM h -1 and 12 ± 4 nM h -1 respectively. Apparent quantum yields averaged 0.07 ± 0.02. Production was largely dominated by sunlight, with some dependence on chromophoric dissolved organic matter (CDOM) levels in waters with high absorption coefficients. Peroxide levels measured here are sufficient to cause oxidative-stress-induced mortality of bacteria, affect FIB diel cycling and impact microbial water quality in marine bathing waters.

The study of hydrogen peroxide level under cisplatin action using genetically encoded sensor hyper

Science.gov (United States)

Belova, A. S.; Orlova, A. G.; Maslennikova, A. V.; Brilkina, A. A.; Balalaeva, I. V.; Antonova, N. O.; Mishina, N. M.; Shakhova, N. M.; Belousov, V. V.

2014-03-01

The aim of the work was to study the participation of hydrogen peroxide in reaction of cervical cancer cell line HeLa Kyoto on cisplatin action. Determination of hydrogen peroxide level was performed using genetically encoded fluorescent sensor HyPer2. The dependence of cell viability on cisplatin concentration was determined using MTT assay. Mechanisms of cell death as well as HyPer2 reaction was revealed by flow cytometry after 6-hours of incubation with cisplatin in different concentrations. Cisplatin used in low concentrations had no effect on hydrogen peroxide level in HeLa Kyoto cells. Increase of HyPer2 fluorescence was detected only after exposure with cisplatin in high concentration. The reaction was not the consequence of cell death.

Preparation of water soluble chitosan by hydrolysis using hydrogen peroxide.

Science.gov (United States)

Xia, Zhenqiang; Wu, Shengjun; Chen, Jinhua

2013-08-01

Chitosan is not soluble in water, which limits its wide application particularly in the medicine and food industry. In the present study, water soluble chitosan (WSC) was prepared by hydrolyzing chitosan using hydrogen peroxide under the catalysis of phosphotungstic acid in homogeneous phase. Factors affecting hydrolysis were investigated and the optimal hydrolysis conditions were determined. The WSC structure was characterized by Fourier transform infrared spectroscopy. The resulting products were composed of chitooligosaccharides of DP 2-9. The WSC content of the product and the yield were 94.7% and 92.3% (w/w), respectively. The results indicate that WSC can be effectively prepared by hydrolysis of chitosan using hydrogen peroxide under the catalysis of phosphotungstic acid. Copyright © 2013 Elsevier B.V. All rights reserved.

Hydrogen Peroxide Cycling in High-Temperature Acidic Geothermal Springs and Potential Implications for Oxidative Stress Response

Directory of Open Access Journals (Sweden)

Margaux M. Meslé

2017-05-01

Full Text Available Hydrogen peroxide (H2O2, superoxide (O2•-, and hydroxyl radicals (OH• are produced in natural waters via ultraviolet (UV light-induced reactions between dissolved oxygen (O2 and organic carbon, and further reaction of H2O2 and Fe(II (i.e., Fenton chemistry. The temporal and spatial dynamics of H2O2 and other dissolved compounds [Fe(II, Fe(III, H2S, O2] were measured during a diel cycle (dark/light in surface waters of three acidic geothermal springs (Beowulf Spring, One Hundred Springs Plain, and Echinus Geyser Spring; pH = 3–3.5, T = 68–80°C in Norris Geyser Basin, Yellowstone National Park. In situ analyses showed that H2O2 concentrations were lowest (ca. 1 μM in geothermal source waters containing high dissolved sulfide (and where oxygen was below detection and increased by 2-fold (ca. 2–3 μM in oxygenated waters corresponding to Fe(III-oxide mat formation down the water channel. Small increases in dissolved oxygen and H2O2 were observed during peak photon flux, but not consistently across all springs sampled. Iron-oxide microbial mats were sampled for molecular analysis of ROS gene expression in two primary autotrophs of acidic Fe(III-oxide mat ecosystems: Metallosphaera yellowstonensis (Archaea and Hydrogenobaculum sp. (Bacteria. Expression (RT-qPCR assays of specific stress-response genes (e.g., superoxide dismutase, peroxidases of the primary autotrophs were used to evaluate possible changes in transcription across temporal, spatial, and/or seasonal samples. Data presented here documented the presence of H2O2 and general correlation with dissolved oxygen. Moreover, two dominant microbial populations expressed ROS response genes throughout the day, but showed less expression of key genes during peak sunlight. Oxidative stress response genes (especially external peroxidases were highly-expressed in microorganisms within Fe(III-oxide mat communities, suggesting a significant role for these proteins during survival and growth in

Hydrogen peroxide in exhaled breath condensate: A clinical study

Directory of Open Access Journals (Sweden)

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.

Heme oxygenase is the major 32-kDa stress protein induced in human skin fibroblasts by UVA radiation, hydrogen peroxide, and sodium arsenite

International Nuclear Information System (INIS)

Keyse, S.M.; Tyrrell, R.M.

1989-01-01

We have shown that UVA (320-380 nm) radiation, hydrogen peroxide, and sodium arsenite induce a stress protein of approximately 32 kDa in human skin fibroblasts. The synthesis and cloning of cDNA from arsenite-induced mRNA populations have now allowed us to unequivocally identify the 32-kDa protein as heme oxygenase. By mRNA analysis we have shown that the heme oxygenase gene is also induced in cultured human skin fibroblasts by UVA radiation, hydrogen peroxide, cadmium chloride, iodoacetamide, and menadione. The known antioxidant properties of heme catabolites taken together with the observation of a high level of induction of the enzyme in cells from an organ not involved in hemoglobin breakdown strongly supports the proposal that the induction of heme oxygenase may be a general response to oxidant stress and constitutes an important cellular defense mechanism against oxidative damage

Decontamination of adsorbed chemical warfare agents on activated carbon using hydrogen peroxide solutions.

Science.gov (United States)

Osovsky, Ruth; Kaplan, Doron; Nir, Ido; Rotter, Hadar; Elisha, Shmuel; Columbus, Ishay

2014-09-16

Mild treatment with hydrogen peroxide solutions (3-30%) efficiently decomposes adsorbed chemical warfare agents (CWAs) on microporous activated carbons used in protective garments and air filters. Better than 95% decomposition of adsorbed sulfur mustard (HD), sarin, and VX was achieved at ambient temperatures within 1-24 h, depending on the H2O2 concentration. HD was oxidized to the nontoxic HD-sulfoxide. The nerve agents were perhydrolyzed to the respective nontoxic methylphosphonic acids. The relative rapidity of the oxidation and perhydrolysis under these conditions is attributed to the microenvironment of the micropores. Apparently, the reactions are favored due to basic sites on the carbon surface. Our findings suggest a potential environmentally friendly route for decontamination of adsorbed CWAs, using H2O2 without the need of cosolvents or activators.

Electrochemical reduction of hydrogen peroxide on stainless steel

Indian Academy of Sciences (India)

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wide range of industrial processes such as food processing (e.g. in the ... tron transfer effect of mitochondria.4 These radicals. (reactive .... of H2O2 without undergoing fouling or poisoning due to any inter- .... adsorbed OHads species was shown operative at po- tentials of .... Douglass W C 2003 Hydrogen peroxide medical.

Treatment of Row Leachate Using Catalytic Wet Oxidation Processes in Combination Hydrogen Peroxide, A Case Study of Isfahan Composting Factory Leachate

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Behrouz Karimi

2013-08-01

Full Text Available Treatment of toxic organic compounds is one of the major applications of the Wet Air Oxidation (WAO processes. The process can be defined  as the oxidation of substances, either in the form of solutions or suspensions, with the use of an oxidant (oxygen or air at elevated pressure and temperature. The aim of this paper was to study of Catalytic Wet Oxidation (CWAO with hydrogen peroxide to improve removal efficiency of organic matter and ammonia mainly produced in Isfahan composting factory leachate. The experiment was carried out by adding 1.5 Lit pretreated leachate sample to 3 Lit autoclave reactor. Four parameters are considered: pressure (8–12 bar; temperature (100–300 °C; retention time (30–90 min; H2O2 (1–5 mL/L.The highest removal efficiencies of COD and BOD were achieved at 300°C; approximately 44% and 48% were destroyed, respectively. On the other hand, highest ammonium removal efficiency was achieved at 100 °C in which approximately 63.8% was removed. The efficiency of aqueous phase oxidation can be largely improved by the use of H2O2 as catalyst. Therefore, catalytic wet oxidation would provide an environmentally attractive option for control of organic and toxic wastes problems. Temperature was found to be the most important control variable of the wet oxidation process of leachate.

Mechanistic insights into the bleaching of melanin by alkaline hydrogen peroxide.

Science.gov (United States)

Smith, R A W; Garrett, B; Naqvi, K R; Fülöp, A; Godfrey, S P; Marsh, J M; Chechik, V

2017-07-01

This work aims to determine the roles of reactive oxygen species HO∙ and HO 2 - in the bleaching of melanins by alkaline hydrogen peroxide. Experiments using melanosomes isolated from human hair indicated that the HO∙ radical generated in the outside solution does not contribute significantly to bleaching. However, studies using soluble Sepia melanin demonstrated that both HO 2 - and HO∙ will individually bleach melanin. Additionally, when both oxidants are present, bleaching is increased dramatically in both rate and extent. Careful experimental design enabled the separation of the roles and effects of these key reactive species, HO∙ and HO 2 - . Rationalisation of the results presented, and review of previous literature, allowed the postulation of a simplified general scheme whereby the strong oxidant HO∙ is able to pre-oxidise melanin units to o-quinones enabling more facile ring opening by the more nucleophilic HO 2 - . In this manner the efficiency of the roles of both species is maximised. Copyright © 2017 Elsevier Inc. All rights reserved.

Metabolic responses of Beauveria bassiana to hydrogen peroxide-induced oxidative stress using an LC-MS-based metabolomics approach.

Science.gov (United States)

Zhang, Chen; Wang, Wei; Lu, Ruili; Jin, Song; Chen, Yihui; Fan, Meizhen; Huang, Bo; Li, Zengzhi; Hu, Fenglin

2016-06-01

The entomopathogenic fungus, Beauveria bassiana, is commonly used as a biological agent for pest control. Environmental and biological factors expose the fungus to oxidative stress; as a result, B. bassiana has adopted a number of anti-oxidant mechanisms. In this study, we investigated metabolites of B. bassiana that are formed in response to oxidative stress from hydrogen peroxide (H2O2) by using a liquid chromatography mass spectrometry (LC-MS) approach. Partial least-squares discriminant analysis (PLS-DA) revealed differences between the control and the H2O2-treated groups. Hierarchical cluster analysis (HCA) showed 18 up-regulated metabolites and 25 down-regulated metabolites in the H2O2-treated fungus. Pathway analysis indicated that B. bassiana may be able to alleviate oxidative stress by enhancing lipid catabolism and glycometabolism, thus decreasing membrane polarity and preventing polar H2O2 or ROS from permeating into fungal cells and protecting cells against oxidative injury. Meanwhile, most of the unsaturated fatty acids that are derived from glycerophospholipids hydrolysis can convert into oxylipins through autoxidation, which can prevent the reactive oxygen of H2O2 from attacking important macromolecules of the fungus. Results showed also that H2O2 treatment can enhance mycotoxins production which implies that oxidative stress may be able to increase the virulence of the fungus. In comparison to the control group, citric acid and UDP-N-acetylglucosamine were down-regulated, which suggested that metabolic flux was occurring to the TCA cycle and enhancing carbohydrate metabolism. The findings from this study will contribute to the understanding of how the molecular mechanisms of fungus respond to environmental and biological stress factors as well as how the manipulation of such metabolisms may lead to selection of more effective fungal strains for pest control. Copyright © 2016 Elsevier Inc. All rights reserved.

Thiol peroxidases mediate specific genome-wide regulation of gene expression in response to hydrogen peroxide

Science.gov (United States)

Fomenko, Dmitri E.; Koc, Ahmet; Agisheva, Natalia; Jacobsen, Michael; Kaya, Alaattin; Malinouski, Mikalai; Rutherford, Julian C.; Siu, Kam-Leung; Jin, Dong-Yan; Winge, Dennis R.; Gladyshev, Vadim N.

2011-01-01

Hydrogen peroxide is thought to regulate cellular processes by direct oxidation of numerous cellular proteins, whereas antioxidants, most notably thiol peroxidases, are thought to reduce peroxides and inhibit H2O2 response. However, thiol peroxidases have also been implicated in activation of transcription factors and signaling. It remains unclear if these enzymes stimulate or inhibit redox regulation and whether this regulation is widespread or limited to a few cellular components. Herein, we found that Saccharomyces cerevisiae cells lacking all eight thiol peroxidases were viable and withstood redox stresses. They transcriptionally responded to various redox treatments, but were unable to activate and repress gene expression in response to H2O2. Further studies involving redox transcription factors suggested that thiol peroxidases are major regulators of global gene expression in response to H2O2. The data suggest that thiol peroxidases sense and transfer oxidative signals to the signaling proteins and regulate transcription, whereas a direct interaction between H2O2 and other cellular proteins plays a secondary role. PMID:21282621

Enzyme-free hydrogen peroxide sensor based on Au@Ag@C core-double shell nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Li, Yancai, E-mail: liyancai@mnnu.edu.cn [College of Chemistry & Environment, Minnan Normal University, Zhangzhou 363000 (China); Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou 363000 (China); Zhang, Yayun; Zhong, Yanmei [College of Chemistry & Environment, Minnan Normal University, Zhangzhou 363000 (China); Li, Shunxing [College of Chemistry & Environment, Minnan Normal University, Zhangzhou 363000 (China); Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou 363000 (China)

2015-08-30

Graphical abstract: - Highlights: • A facile method was designed to synthesize Au@Ag@C core-double shell nanocomposites. • Carbon nanomaterials at the outermost layer could protect Au and Ag nanoparticles from oxidation and aggregation. • The Au@Ag@C core-double shell nanocomposites showed high sensitivity and selectivity to electrocatalytic reduction of hydrogen peroxide. • The hydrogen peroxide sensor has a wide linear range of 5.0 μM to 4.75 mM and a limit of detection as low as 0.14 μM. - Abstract: The well-designed Au@Ag@C core-double shell nanocomposites were synthesized via a facile method, and were used to fabricate an enzyme-free amperometric hydrogen peroxide (H{sub 2}O{sub 2}) sensor. The size, shape, elementary composition and structure of the nanocomposites were characterized by transmission electron microscope (TEM), energy-dispersed spectrum (EDS) and X-ray diffraction (XRD). The outermost layer of the nanocomposites was amorphous carbon, the second layer was Ag and the core was Au. The Au@Ag@C core-double shell nanocomposites exhibit attractive activity for electrocatalytic reduction of H{sub 2}O{sub 2} according to the electrochemical experiments. It also demonstrates the H{sub 2}O{sub 2} sensor possess well performance with a wide linear range of 5.0 μM to 4.75 mM and a limit of detection (LOD) as low as 0.14 μM (S/N = 3). Furthermore, the interference from the common interfering species, such as glucose, ascorbic acid, dopamine and uric acid can be effectively avoided. In a word, the Au@Ag@C nanocomposites are promising candidates for enzyme-free H{sub 2}O{sub 2} sensor.

Influence of hydrogen peroxide on the stability and optical properties of CdS quantum dots in gelatin

Energy Technology Data Exchange (ETDEWEB)

Klyuev, V.G.; Volykhin, D.V., E-mail: volykhin.d@ya.ru; Ivanova, A.A.

2017-03-15

Influence of hydrogen peroxide on the stability and optical characteristics of CdS quantum dots obtained by aqueous synthesis in gelatin is investigated. It is shown that the action of hydrogen peroxide on the CdS quantum dots reduces the average particle size, increases monodispersity of particle size distribution, and also increases the photoluminescence intensity. A model that explains the behavior of CdS quantum dots photoluminescence with a decrease of particle size as a result of treatment with hydrogen peroxide is presented.

An Analysis of Dental Enamel after Bleaching using 35% Hydrogen Peroxide with Energy-dispersive X-ray Spectroscopy

OpenAIRE

Asmawati, Dr. drg. Asmawati, M.Kes

2017-01-01

Hydrogen peroxide (H2O2) is an effective bleaching agent of tooth whitening, but its use causes changes in the chemical composition of the elements that configure tooth enamel. The purpose of this study is to determine whether there are changes in the composition of the elements that configure the tooth enamel after bleaching using 35% hydrogen peroxide. Background: Hydrogen peroxide (H2O2) is an effective bleaching agent of tooth whitening, but its use causes changes in the chemical compo...

Effect of foliar application of salicylic acid, hydrogen peroxide

Indian Academy of Sciences (India)

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

Dissolution of ion exchange resin by hydrogen peroxide

International Nuclear Information System (INIS)

Lee, S.C.

1981-08-01

The resin dissolution process was conducted successfully in full-scale equipment at the SRL Semiworks. A solution containing 0.001M Fe 2+ , or Fe 3+ , and 3 vol % H 2 O 2 in 0.1M HNO 3 is sufficient to dissolve up to 40 vol % resin slurry (Dowex 50W-X8). Foaming and pressurization can be eliminated by maintaining the dissolution temperature below 99 0 C. The recommended dissolution temperature range is 85 to 90 0 C. Premixing hydrogen peroxide with all reactants will not create a safety hazard, but operating with a continual feed of hydrogen peroxide is recommended to control the dissolution rate. An air sparging rate of 1.0 to 1.5 scfm will provide sufficient mixing. Spent resin from chemical separation contains DTPA (diethylenetriaminepentaacetic acid) residue, and the resin must be washed with 0.1M NH 4 OH to remove excess DTPA before dissolution. Gamma irradiation of resin up to 4 kW-hr/L did not change the dissolution rate significantly

Developing an electrochemical sensor based on a carbon paste electrode modified with nano-composite of reduced graphene oxide and CuFe2O4 nanoparticles for determination of hydrogen peroxide.

Science.gov (United States)

Benvidi, Ali; Nafar, Mohammad Taghi; Jahanbani, Shahriar; Tezerjani, Marzieh Dehghan; Rezaeinasab, Masoud; Dalirnasab, Sudabeh

2017-06-01

In this paper, a highly sensitive voltammetric sensor based on a carbon paste electrode with CuFe 2 O 4 nanoparticle (RGO/CuFe 2 O 4 /CPE) was designed for determination of hydrogen peroxide (H 2 O 2 ). The electrocatalytic reduction of H 2 O 2 was examined using various techniques such as cyclic voltammetry (CV), chronoamperometry, amperometry and differential pulse voltammetry (DPV). CuFe 2 O 4 nanoparticles were synthesized by co-precipitation method and characterized with scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) techniques. Then, a high conductive platform based on a carbon paste electrode modified with RGO and CuFe 2 O 4 nanoparticles was prepared as a suitable platform for determination of hydrogen peroxide. Under the optimum conditions (pH5), the modified electrode indicated a fast amperometric response of determination of hydrogen peroxide. Also, the peak current of differential pulse voltammetry (DPV) of hydrogen peroxide is increased linearly with its concentration in the ranges of 2 to 10μM and 10 to 1000μM. The obtained detection limit for hydrogen peroxide was evaluated to be 0.064μM by DPV. The designed sensor was successfully applied for the assay of hydrogen peroxide in biological and pharmaceutical samples such as milk, green tea, and hair dye cream and mouthwash solution. Copyright © 2017. Published by Elsevier B.V.

Kinetic spectrophotometric determination of Bi(III based on its catalytic effect on the oxidation of phenylfluorone by hydrogen peroxide

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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.

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

Science.gov (United States)

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

1992-01-01

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

Insights into the role of oxidative stress in the pathology of Friedreich ataxia using peroxidation resistant polyunsaturated fatty acids

Directory of Open Access Journals (Sweden)

M. Grazia Cotticelli

2013-01-01

Full Text Available Friedreich ataxia is an autosomal recessive, inherited neuro- and cardio-degenerative disorder characterized by progressive ataxia of all four limbs, dysarthria, areflexia, sensory loss, skeletal deformities, and hypertrophic cardiomyopathy. Most disease alleles have a trinucleotide repeat expansion in the first intron of the FXN gene, which decreases expression of the encoded protein frataxin. Frataxin is involved in iron–sulfur-cluster (ISC assembly in the mitochondrial matrix, and decreased frataxin is associated with ISC-enzyme and mitochondrial dysfunction, mitochondrial iron accumulation, and increased oxidative stress. To assess the role of oxidative stress in lipid peroxidation in Friedreich ataxia we used the novel approach of treating Friedreich ataxia cell models with polyunsaturated fatty acids (PUFAs deuterated at bis-allylic sites. In ROS-driven oxidation of PUFAs, the rate-limiting step is hydrogen abstraction from a bis-allylic site; isotopic reinforcement (deuteration of bis-allylic sites slows down their peroxidation. We show that linoleic and α-linolenic acids deuterated at the peroxidation-prone bis-allylic positions actively rescue oxidative-stress-challenged Friedreich ataxia cells. The protective effect of the deuterated PUFAs is additive in our models with the protective effect of the CoQ10 analog idebenone, which is thought to decrease the production of free radicals. Moreover, the administration of deuterated PUFAs resulted in decreased lipid peroxidation as measured by the fluorescence of the fatty acid analog C11-BODIPY (581/591 probe. Our results are consistent with a role for lipid peroxidation in Friedreich ataxia pathology, and suggest that the novel approach of oral delivery of isotope-reinforced PUFAs may have therapeutic potential in Friedreich ataxia and other disorders involving oxidative stress and lipid peroxidation.

Superoxide dismutase 1-mediated production of ethanol- and DNA-derived radicals in yeasts challenged with hydrogen peroxide: molecular insights into the genome instability of peroxiredoxin-null strains.

Science.gov (United States)

Ogusucu, Renata; Rettori, Daniel; Netto, Luis E S; Augusto, Ohara

2009-02-27

Peroxiredoxins are receiving increasing attention as defenders against oxidative damage and sensors of hydrogen peroxide-mediated signaling events. In the yeast Saccharomyces cerevisiae, deletion of one or more isoforms of the peroxiredoxins is not lethal but compromises genome stability by mechanisms that remain under scrutiny. Here, we show that cytosolic peroxiredoxin-null cells (tsa1Deltatsa2Delta) are more resistant to hydrogen peroxide than wild-type (WT) cells and consume it faster under fermentative conditions. Also, tsa1Deltatsa2Delta cells produced higher yields of the 1-hydroxyethyl radical from oxidation of the glucose metabolite ethanol, as proved by spin-trapping experiments. A major role for Fenton chemistry in radical formation was excluded by comparing WT and tsa1Deltatsa2Delta cells with respect to their levels of total and chelatable metal ions and of radical produced in the presence of chelators. The main route for 1-hydroxyethyl radical formation was ascribed to the peroxidase activity of Cu,Zn-superoxide dismutase (Sod1), whose expression and activity increased approximately 5- and 2-fold, respectively, in tsa1Deltatsa2Delta compared with WT cells. Accordingly, overexpression of human Sod1 in WT yeasts led to increased 1-hydroxyethyl radical production. Relevantly, tsa1Deltatsa2Delta cells challenged with hydrogen peroxide contained higher levels of DNA-derived radicals and adducts as monitored by immuno-spin trapping and incorporation of (14)C from glucose into DNA, respectively. The results indicate that part of hydrogen peroxide consumption by tsa1Deltatsa2Delta cells is mediated by induced Sod1, which oxidizes ethanol to the 1-hydroxyethyl radical, which, in turn, leads to increased DNA damage. Overall, our studies provide a pathway to account for the hypermutability of peroxiredoxin-null strains.

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

Science.gov (United States)

Putt, Karson S; Pugh, Randall B

2013-01-01

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

A Modified Fluorimetric Method for Determination of Hydrogen Peroxide Using Homovanillic Acid Oxidation Principle

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Biswaranjan Paital

2014-01-01

Full Text Available Hydrogen peroxide (H2O2 level in biological samples is used as an important index in various studies. Quantification of H2O2 level in tissue fractions in presence of H2O2 metabolizing enzymes may always provide an incorrect result. A modification is proposed for the spectrofluorimetric determination of H2O2 in homovanillic acid (HVA oxidation method. The modification was included to precipitate biological samples with cold trichloroacetic acid (TCA, 5% w/v followed by its neutralization with K2HPO4 before the fluorimetric estimation of H2O2 is performed. TCA was used to precipitate the protein portions contained in the tissue fractions. After employing the above modification, it was observed that H2O2 content in tissue samples was ≥2 fold higher than the content observed in unmodified method. Minimum 2 h incubation of samples in reaction mixture was required for completion of the reaction. The stability of the HVA dimer as reaction product was found to be >12 h. The method was validated by using known concentrations of H2O2 and catalase enzyme that quenches H2O2 as substrate. This method can be used efficiently to determine more accurate tissue H2O2 level without using internal standard and multiple samples can be processed at a time with additional low cost reagents such as TCA and K2HPO4.

A compact process for the treatment of olive mill wastewater by combining wet hydrogen peroxide catalytic oxidation and biological techniques

International Nuclear Information System (INIS)

Azabou, Samia; Najjar, Wahiba; Bouaziz, Mohamed; Ghorbel, Abdelhamid; Sayadi, Sami

2010-01-01

A system based on combined actions of catalytic wet oxidation and microbial technologies for the treatment of highly polluted OMW containing polyphenols was studied. The wet hydrogen peroxide catalytic oxidation (WHPCO) process has been investigated in the semi-batch mode at atmospheric pressure, using aluminium-iron-pillared inter layer clay ((Al-Fe)PILC), under two different catalytic processes: ((Al-Fe)PILC/H 2 O 2 /ultraviolet radiations) at 25 deg. C and ((Al-Fe)PILC/H 2 O 2 ) at 50 deg. C. The results show that raw OMW was resistant to the photocatalytic process. However ((Al-Fe)PILC/H 2 O 2 ), system operating at 50 deg. C reduced considerably the COD, colour and total phenolic contents, and thus decreased the inhibition of the marine photobacteria Vibrio fischeri luminescence by 70%. This study also examined the feasibility of coupling WHPCO and anaerobic digestion treatment. Biomethanisation experiments performed with raw OMW or pre-treated OMW proved that pre-treatments with ((Al-Fe)PILC/H 2 O 2 ) system, for more than 2 h, resulted in higher methane production. Both untreated OMW as well as 2-h pre-treated OMW revealed as toxic to anaerobic bacteria.

Selective Precipitation of Thorium lodate from a Tartaric Acid-Hydrogen Peroxide Medium Application to Rapid Spectrophotometric Determination of Thorium in Silicate Rocks and in Ores

Science.gov (United States)

Grimaldi, F.S.

1957-01-01

This paper presents a selective iodate separation of thorium from nitric acid medium containing d-tartaric acid and hydrogen peroxide. The catalytic decomposition of hydrogen peroxide is prevented by the use of 8quinolinol. A few micrograms of thorium are separated sufficiently clean from 30 mg. of such oxides as cerium, zirconium, titanium, niobium, tantalum, scandium, or iron with one iodate precipitation to allow an accurate determination of thorium with the thoronmesotartaric acid spectrophotometric method. The method is successful for the determination of 0.001% or more of thorium dioxide in silicate rocks and for 0.01% or more in black sand, monazite, thorite, thorianite, eschynite, euxenite, and zircon.

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

Science.gov (United States)

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

2014-03-01

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

Hydrogen peroxide (H2O2): a review of its use in surgery.

Science.gov (United States)

Urban, Michael Vincent; Rath, Thomas; Radtke, Christine

2017-11-16

Hydrogen peroxide has been used in medicine for more than 100 years. It is known in surgery as a highly useful irrigation solution by virtue of both its hemostatic and its antimicrobial effects. Due to its possible negative effect on wound healing and its cytotoxic effect in higher concentrations, there are concerns about the safety of its use. The objective of this paper is to review the safety and beneficial effects of hydrogen peroxide.

Photo-oxidation of histidine peptides yields high concentrations of unstable peroxides

International Nuclear Information System (INIS)

Policarpio, V.V.; Hawkins, C.L.; Davies, M.J.

2003-01-01

Oxidation of proteins by UV, and visible light in the presence of sensitizers, results in side chain modification as well as aggregation and fragmentation. In particular, singlet oxygen has been reported to oxidize Met, Trp, Tyr, Cys and His side chains in a selective manner. In this study the oxidation of histidine and its derivatives, and His-containing peptides is examined using a range of sensitizers, to determine whether peroxides are major intermediates, and the mechanism of formation of these species. Visible light-sensitised oxidation of Gly-His-Gly in the presence of oxygen and rose bengal gives unstable substrate-derived peroxides with the peroxide yield increasing with increasing photolysis time. Similar behaviour was detected with other photosensitizers, though the peroxide yields varied with the sensitizer at identical concentrations with rose bengal > aluminium phthalocyanine > hematoporphyrin IX > zinc phthalocyanine > tetrakisporphine. The peroxide yield was decreased in the presence of azide and enhanced when deuterium oxide was employed as the solvent, consistent with peroxide formation being singlet oxygen mediated. Experiments using anoxic conditions gave low yields of peroxides confirming the oxygen-dependence of these reactions. HPLC analysis showed rapid loss of the parent peptide, with subsequent formation of both stable and unstable products; these are currently being characterized by MS and NMR. Similar behavior has been observed with other His derivatives. The yield of singlet oxygen formed in these reactions has been estimated using a bleaching assay (N, N-dimethyl-4-nitrosoaniline). Quantification of singlet oxygen formation and Gly-His-Gly derived peroxide during rose bengal-mediated photooxidation indicated a conversion efficiency of the initial singlet oxygen into substrate-derived peroxides of ca. 75% indicating that peroxide formation is a highly efficient and major reaction pathway

EFFLUENT TREATMENT FACILITY PEROXIDE DESTRUCTION CATALYST TESTING

International Nuclear Information System (INIS)

HALGREN DL

2008-01-01

The 200 Area Effluent Treatment Facility (ETF) main treatment train includes the peroxide destruction module (PDM) where the hydrogen peroxide residual from the upstream ultraviolet light/hydrogen peroxide oxidation unit is destroyed. Removal of the residual peroxide is necessary to protect downstream membranes from the strong oxidizer. The main component of the PDM is two reaction vessels utilizing granular activated carbon (GAC) as the reaction media. The PDM experienced a number of operability problems, including frequent plugging, and has not been utilized since the ETF changed to groundwater as the predominant feed. The unit seemed to be underperforming in regards to peroxide removal during the early periods of operation as well. It is anticipated that a functional PDM will be required for wastewater from the vitrification plant and other future streams. An alternate media or methodology needs to be identified to replace the GAC in the PDMs. This series of bench scale tests is to develop information to support an engineering study on the options for replacement of the existing GAC method for peroxide destruction at the ETF. A number of different catalysts will be compared as well as other potential methods such as strong reducing agents. The testing should lead to general conclusions on the viability of different catalysts and identify candidates for further study and evaluation

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

Directory of Open Access Journals (Sweden)

Karson S Putt

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

Cyclic voltammetry, square wave voltammetry, electrochemical impedance spectroscopy and colorimetric method for hydrogen peroxide detection based on chitosan/silver nanocomposite

Directory of Open Access Journals (Sweden)

Hoang V. Tran

2018-05-01

Full Text Available In this paper, we demonstrate a promising method to fabricate a non-enzymatic stable, highly sensitive and selective hydrogen peroxide sensor based on a chitosan/silver nanoparticles (CS/AgNPs hybrid. Using this composite, we elaborated both electrochemical and colorimetric sensors for hydrogen peroxide detection. The colorimetric sensor is based on a homogenous reaction which fades the color of CS/AgNPs solutions from red-orange to colorless depending on hydrogen peroxide concentration. For the electrochemical sensor, CS/AgNPs were immobilized on glassy carbon electrodes and hydrogen peroxide was measured using cyclic voltammetry, square wave voltammetry and electrochemical impedance spectroscopy. The response time is less than 10 s and the detection limit is 5 μM. Keywords: Spectrophotometric detection, Electrochemical impedance spectroscopy, Square wave voltammetry, Cyclic voltammetry, Chitosan/silver nanoparticles (CS/AgNPs hybrid, Hydrogen peroxide

Trace detection of hydrogen peroxide vapor using a carbon-nanotube-based chemical sensor.

Science.gov (United States)

Lu, Yijiang; Meyyappan, M; Li, Jing

2011-06-20

The sensitive detection of hydrogen peroxide in the vapor phase is achieved using a nanochemical sensor consisting of single-walled carbon nanotubes as the sensing material. The interdigitated electrode-based sensor is constructed using a simple and standard microfabrication approach. The test results indicate a sensing capability of 25 ppm and response and recovery times in seconds. The sensor array consisting of 32 sensor elements with variations in sensing materials is capable of discriminating hydrogen peroxide from water and methanol. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photocatalytic transformation of dyes and by-products in the presence of hydrogen peroxide.

Science.gov (United States)

Subba Rao, K V; Subrahmanyam, M; Boule, P

2003-08-01

The efficiency of the photocatalytic degradation of dyes and dyeing industry pollutants on immobilized photocatalysts can be improved by addition of hydrogen peroxide, due to its photocatalytic decomposition on TiO2. Experiments were carried out with two azodyes, Acid Orange-7 (AO-7) and Tartrazine (Tart), with 3-nitrobenzenesulfonic add (3-NBSA) which is a chemical intermediate in the dye industry and with real industrial wastewaters, using a thin-film fixed bed reactor. The effect of hydrogen peroxide is only significant for concentrations higher than 5 x 10(-3) M (170 mg l(-1)).

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

Directory of Open Access Journals (Sweden)

Edina Németh

2005-01-01

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

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

International Nuclear Information System (INIS)

Faimon, Jiri; Stelcl, Jindrich; Kubesova, Svatava; Zimak, Jiri

2003-01-01

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

Determination and analysis of uptake of gaseous hydrogen peroxide by red spruce seedlings, determined by CSTR-type chamber experiments

International Nuclear Information System (INIS)

Claiborn, C.S.; Aneja, V.P.; Carbonell, R.G.

1991-01-01

In order to better understand the pathways for damage, the fate of gaseous hydrogen peroxide in red spruce needles was examined. The uptake of gaseous hydrogen peroxide by red spruce trees was determined from controlled exposure chamber experiments in which the chamber behaved as a Continuous Stirred Tank Reactor (CSTR). The results from these experiments were analyzed using a detailed transport model developed from fundamental principles, in order to determine the fate of hydrogen peroxide in the needles and characterize the exposure. The chamber was specially designed to accommodate highly reactive gases. All inner surfaces were Teflon-coated to minimize wall losses. Fluxes of hydrogen peroxide, carbon dioxide, and water vapor were determined. Both daytime and nighttime conditions were examined. Although other investigators have reported that the flux of other, less water-soluble pollutants to red spruce decreases at night when the stomata closes, the hydrogen peroxide flux did not exhibit this behavior. The results of these studies suggest that, at the concentrations observed in the atmosphere, hydrogen peroxide does not reach the inner, mesophyll tissues, but is lost in water condensing in the cuticular wax residing in the stomatal antechamber, above the stomata. The implications of the condensation in the stomatal antechamber and subsequent reactions occurring in this water for forest damage are discussed

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

Science.gov (United States)

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

2016-08-01

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

Oxidative Stress Induces Senescence in Cultured RPE Cells.

Science.gov (United States)

Aryan, Nona; Betts-Obregon, Brandi S; Perry, George; Tsin, Andrew T

2016-01-01

The aim of this research is to determine whether oxidative stress induces cellular senescence in human retinal pigment epithelial cells. Cultured ARPE19 cells were subjected to different concentrations of hydrogen peroxide to induce oxidative stress. Cells were seeded into 24-well plates with hydrogen peroxide added to cell medium and incubated at 37°C + 5% CO2 for a 90-minute period [at 0, 300, 400 and 800 micromolar (MCM) hydrogen peroxide]. The number of viable ARPE19 cells were recorded using the Trypan Blue Dye Exclusion Method and cell senescence was measured by positive staining for senescence-associated beta-galactosidase (SA-beta-Gal) protein. Without hydrogen peroxide treatment, the number of viable ARPE19 cells increased significantly from 50,000 cells/well to 197,000 within 72 hours. Treatment with hydrogen peroxide reduced this level of cell proliferation significantly (to 52,167 cells at 400 MCM; to 49,263 cells at 800 MCM). Meanwhile, cells with a high level of positive senescence-indicator SA-Beta-Gal-positive staining was induced by hydrogen peroxide treatment (from a baseline level of 12% to 80% at 400 MCM and at 800 MCM). Our data suggests that oxidative stress from hydrogen peroxide treatment inhibited ARPE19 cell proliferation and induced cellular senescence.

Utilizing a CdTe quantum dots-enzyme hybrid system for the determination of both phenolic compounds and hydrogen peroxide.

Science.gov (United States)

Yuan, Jipei; Guo, Weiwei; Wang, Erkang

2008-02-15

In this paper, we attempt to construct a simple and sensitive detection method for both phenolic compounds and hydrogen peroxide, with the successful combination of the unique property of quantum dots and the specificity of enzymatic reactions. In the presence of H2O2 and horseradish peroxidase, phenolic compounds can quench quantum dots' photoluminescence efficiently, and the extent of quenching is severalfold to more than 100-fold increase. Quinone intermediates produced from the enzymatic catalyzed oxidation of phenolic compounds were believed to play the main role in the photoluminescence quenching. Using a quantum dots-enzyme system, the detection limits for phenolic compounds and hydrogen peroxide were detected to be approximately 10(-7) mol L(-1). The coupling of efficient quenching of quantum dot photoluminescence by quinone and the effective enzymatic reactions make this a simple and sensitive method for phenolic compound detection and great potential in the development of H2O2 biosensors for various analytes.

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

Directory of Open Access Journals (Sweden)

Shirin Karbalaye Golizadeh

2016-03-01

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

'No touch' technologies for environmental decontamination: focus on ultraviolet devices and hydrogen peroxide systems.

Science.gov (United States)

Weber, David J; Kanamori, Hajime; Rutala, William A

2016-08-01

This article reviews 'no touch' methods for disinfection of the contaminated surface environment of hospitalized patients' rooms. The focus is on studies that assessed the effectiveness of ultraviolet (UV) light devices, hydrogen peroxide systems, and self-disinfecting surfaces to reduce healthcare-associated infections (HAIs). The contaminated surface environment in hospitals plays an important role in the transmission of several key nosocomial pathogens including methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus spp., Clostridium difficile, Acinetobacter spp., and norovirus. Multiple clinical trials have now demonstrated the effectiveness of UV light devices and hydrogen peroxide systems to reduce HAIs. A limited number of studies have suggested that 'self-disinfecting' surfaces may also decrease HAIs. Many studies have demonstrated that terminal cleaning and disinfection with germicides is often inadequate and leaves environmental surfaces contaminated with important nosocomial pathogens. 'No touch' methods of room decontamination (i.e., UV devices and hydrogen peroxide systems) have been demonstrated to reduce key nosocomial pathogens on inoculated test surfaces and on environmental surfaces in actual patient rooms. Further UV devices and hydrogen peroxide systems have been demonstrated to reduce HAI. A validated 'no touch' device or system should be used for terminal room disinfection following discharge of patients on contact precautions. The use of a 'self-disinfecting' surface to reduce HAI has not been convincingly demonstrated.

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

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Halimeh Rajabzade

2012-01-01

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

Synthesis of zirconia-immobilized copper chelates for catalytic decomposition of hydrogen peroxide and the oxidation of polycyclic aromatic hydrocarbons

Czech Academy of Sciences Publication Activity Database

Baldrian, Petr; Merhautová, Věra; Cajthaml, Tomáš; Nerud, František; Stopka, Pavel; Gorbacheva, O.; Hrubý, Martin; Beneš, Milan J.

2008-01-01

Roč. 72, č. 11 (2008), s. 1721-1726 ISSN 0045-6535 R&D Projects: GA AV ČR IBS5020306 Institutional research plan: CEZ:AV0Z50200510; CEZ:AV0Z40320502; CEZ:AV0Z40500505 Keywords : degradation * polycyclic aromatic hydrocarbons * hydrogen peroxide Subject RIV: EE - Microbiology, Virology Impact factor: 3.054, year: 2008

Peroxides and radiation impairment of oxidative phosphorylation

Energy Technology Data Exchange (ETDEWEB)

Dovgii, I E; Akoev, I G

1975-09-01

An increase in the peroxidase activity of the mitochondria and a simultaneous rise in the amount of peroxide compounds, which are half lipid-like substances, are detected within the first 10 minutes after irradiation (1000 r). A mechanism of radiation impairment of oxidative phosphorylation is connected with the penetration of its inhibitors to the mitochondria due to the disturbed permeability of membranes affected by peroxides.

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

Science.gov (United States)

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

2004-01-01

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

Redox signaling in cardiovascular pathophysiology: A focus on hydrogen peroxide and vascular smooth muscle cells

Directory of Open Access Journals (Sweden)

Chang Hyun Byon

2016-10-01

Full Text Available Oxidative stress represents excessive intracellular levels of reactive oxygen species (ROS, which plays a major role in the pathogenesis of cardiovascular disease. Besides having a critical impact on the development and progression of vascular pathologies including atherosclerosis and diabetic vasculopathy, oxidative stress also regulates physiological signaling processes. As a cell permeable ROS generated by cellular metabolism involved in intracellular signaling, hydrogen peroxide (H2O2 exerts tremendous impact on cardiovascular pathophysiology. Under pathological conditions, increased oxidase activities and/or impaired antioxidant systems results in uncontrolled production of ROS. In a pro-oxidant environment, vascular smooth muscle cells (VSMC undergo phenotypic changes which can lead to the development of vascular dysfunction such as vascular inflammation and calcification. Investigations are ongoing to elucidate the mechanisms for cardiovascular disorders induced by oxidative stress. This review mainly focuses on the role of H2O2 in regulating physiological and pathological signals in VSMC.

Fe(III)-functionalized carbon dots—Highly efficient photoluminescence redox catalyst for hydrogenations of olefins and decomposition of hydrogen peroxide

KAUST Repository

Bourlinos, Athanasios B.

2017-03-21

We present the first bottom-up approach to synthesize Fe(III)-functionalized carbon dots (CDs) from molecular precursors without the need of conventional thermal or microwave treatment and additional reagents. Specifically, sonication of xylene in the presence of anhydrous FeCl3 results in oxidative coupling of the aromatic substrate towards Fe(III)-functionalized CDs. The as-prepared CDs are spherical in shape with a size of 3–8 nm, highly dispersible in organic solvents and display wavelength-dependent photoluminescence (PL). The iron ions attached to the surface endow the CDs with superior catalytic activity for olefin hydrogenation with excellent conversion and selectivity (up to 100%). The Fe(III)-CDs are more effective in the hydrogenation of a series of electron donating or withdrawing olefin substrates compared to conventional homogeneous or heterogeneous Fe(III)-based catalysts. The as-prepared heterogeneous nanocatalyst can be used repeatedly without any loss of catalytic activity. Importantly, the stability of the new catalysts can be easily monitored by PL intensity or quantum yield measurements, which certainly opens the doors for real time monitoring in a range of applications. Additionally, to the best of our knowledge, for the first time, the oxidative property of Fe-CDs was also explored in decomposition of hydrogen peroxide in water with the first order rate constant of 0.7 × 10−2 min−1, proving the versatile catalytic properties of such hybrid systems.

Fe(III)-functionalized carbon dots—Highly efficient photoluminescence redox catalyst for hydrogenations of olefins and decomposition of hydrogen peroxide

KAUST Repository

Bourlinos, Athanasios B.; Rathi, Anuj K.; Gawande, Manoj B.; Hola, Katerina; Goswami, Anandarup; Kalytchuk, Sergii; Karakassides, Michael A.; Kouloumpis, Antonios; Gournis, Dimitrios; Deligiannakis, Yannis; Giannelis, Emmanuel P.; Zboril, Radek

2017-01-01

We present the first bottom-up approach to synthesize Fe(III)-functionalized carbon dots (CDs) from molecular precursors without the need of conventional thermal or microwave treatment and additional reagents. Specifically, sonication of xylene in the presence of anhydrous FeCl3 results in oxidative coupling of the aromatic substrate towards Fe(III)-functionalized CDs. The as-prepared CDs are spherical in shape with a size of 3–8 nm, highly dispersible in organic solvents and display wavelength-dependent photoluminescence (PL). The iron ions attached to the surface endow the CDs with superior catalytic activity for olefin hydrogenation with excellent conversion and selectivity (up to 100%). The Fe(III)-CDs are more effective in the hydrogenation of a series of electron donating or withdrawing olefin substrates compared to conventional homogeneous or heterogeneous Fe(III)-based catalysts. The as-prepared heterogeneous nanocatalyst can be used repeatedly without any loss of catalytic activity. Importantly, the stability of the new catalysts can be easily monitored by PL intensity or quantum yield measurements, which certainly opens the doors for real time monitoring in a range of applications. Additionally, to the best of our knowledge, for the first time, the oxidative property of Fe-CDs was also explored in decomposition of hydrogen peroxide in water with the first order rate constant of 0.7 × 10−2 min−1, proving the versatile catalytic properties of such hybrid systems.

Prestart-up hydrogen peroxide solution washing of NPP unit with the RBMK-type reactor

International Nuclear Information System (INIS)

Gruzdev, N.I.; Man'kina, N.N.; Al'tshuller, M.A.

1979-01-01

Presented are the results of industrial hydrogen peroxide solution washing of condensating-feed system conducted on the second unit of the Kursk NPP. Duration of the washing constituted 8 hours. The hydrogen peroxide concentration during first 4 hours was 10-20 mg/kg at a flow rate of 260 m 2 /h, during the following 4 hours it constituted 2-5 mg/kg at a flow rate of 1000 m 3 /h. It is found out that prestart-up hydrogen peroxide washing of NPP power units with the RBMK-type reactor permits: to simplify essentially the technology and scheme of washing process; to reduce a flow rate of desalt washing water; to except environmental contamination with washing solutions and reagents being neutralized; to reduce the time of washing process; to reduce the time necessary for the achievement of reference water condition factors, and to increase the unit reliability and to improve a radiation situation

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

Science.gov (United States)

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

2016-10-01

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

The influence of hydrogen peroxide on the permeability of protective gloves to resorcinol in hairdressing.

Science.gov (United States)

Lind, Marie-Louise; Johnsson, Stina; Lidén, Carola; Meding, Birgitta; Boman, Anders

2015-01-01

Hairdressers are exposed to hair dye chemicals, for example resorcinol and hydrogen peroxide. Adequate skin protection is an important preventive measure against occupational skin disease. To examine whether hydrogen peroxide may cause deterioration of protective gloves. Permeation of resorcinol through gloves of polyvinylchloride (PVC) (n = 8), natural rubber latex (NRL) (n = 5) and nitrile rubber (NR) (n = 5) was studied in a two-compartment cell, with resorcinol as an indicator for hair dyes. The amount of resorcinol that had permeated was analysed with a high-performance liquid chromatography instrument. Cumulative breakthrough time and permeation rate were compared for hydrogen peroxide-pretreated and untreated gloves. The cumulative breakthrough time was > 1 hr but gloves. Pretreatment of PVC gloves resulted in a slightly decreased breakthrough time, and pretreatment of NRL gloves decreased the permeation rate. No change was recorded in NR gloves. Treatment with hydrogen peroxide had a minor effect on permeation in the tested gloves. NR gloves provided the best protection. However, taking the allergy risk of rubber gloves into account, plastic gloves are recommended in hairdressing. PVC gloves may be used, but not for > 1 hr. Disposable gloves should never be reused, regardless of material. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

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

Science.gov (United States)

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…

The principal phenolic and alcoholic components of wine protect human lymphocytes against hydrogen peroxide- and ionising radiation-induced DNA damage in vitro

International Nuclear Information System (INIS)

Fenech, M.; Greenrod, W.

2003-01-01

the DNA damaging effects of two important oxidants ie hydrogen peroxide and ionising radiation, in this physiologically relevant in vitro system

The basic chemistry and photochemistry behind hydrogen peroxide tooth whitening

NARCIS (Netherlands)

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

2013-01-01

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

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

Science.gov (United States)

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

2014-01-01

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

Hydrogen peroxide biosensor based on microperoxidase-11 immobilized in a silica cavity array electrode.

Science.gov (United States)

Tian, Shu; Zhou, Qun; Gu, Zhuomin; Gu, Xuefang; Zhao, Lili; Li, Yan; Zheng, Junwei

2013-03-30

Hydrogen peroxide biosensor based on the silica cavity array modified indium-doped tin oxide (ITO) electrode was constructed. An array of silica microcavities was fabricated by electrodeposition using the assembled polystyrene particles as template. Due to the resistance gradient of the silica cavity structure, the silica cavity exhibits a confinement effect on the electrochemical reactions, making the electrode function as an array of "soft" microelectrodes. The covalently immobilized microperoxidase-11(MP-11) inside these SiO2 cavities can keep its physiological activities, the electron transfer between the MP-11 and electrode was investigated through electrochemical method. The cyclic voltammetric curve shows a quasi-reversible electrochemical redox behavior with a pair of well-defined redox peaks, the cathodic and anodic peaks are located at -0.26 and -0.15V. Furthermore, the modified electrode exhibits high electrocatalytic activity toward the reduction of hydrogen peroxide and also shows good analytical performance for the amperometric detection of H2O2 with a linear range from 2×10(-6) to 6×10(-4)M. The good reproducibility and long-term stability of this novel electrode not only offer an opportunity for the detection of H2O2 in low concentration, but also provide a platform to construct various biosensors based on many other enzymes. Copyright © 2013 Elsevier B.V. All rights reserved.

Some peculiarities of lipides peroxide oxidation and anti oxidation therapy of duodenal peptic ulcer in the persons who stayed in the zone of the Chernobyl accident

International Nuclear Information System (INIS)

Babak, O.Ya.; Chernyak, A.M.; Goncharova, L.Yi.; Pasyijeshvyilyi, L.M.

1994-01-01

The authors have studied the links of lipides peroxide oxidation (LPO) in the blood plasma, i.e. the level of antioxidant protection at duodenal peptic ulcer (DPU) in the persons who stayed in the zone of the accident at Chernobyl Atomic Power Station. LPO intensification takes place at the expense of the primary stages (spontaneous and hydrogen peroxide induced chemo luminescence) in the liquidators with DPU, when compared with the patients having DPU who did not stay in the zone of the accident. It suggests of exhaustion of cell membranes anti-oxidate protection level which provides atypical course of inflammatory processes in the gastrointestinal tract mucous membrane. The peculiarities of blood plasma LPO changes suggest that it would be reasonable to include antioxidants (Unithiolum) to the complex treatment of the liquidators

Glycerophosphate-dependent hydrogen peroxide production by rat liver mitochondria

Czech Academy of Sciences Publication Activity Database

Ješina, Pavel; Kholová, D.; Bolehovská, R.; Červinková, Z.; Drahota, Zdeněk; Houštěk, Josef

2004-01-01

Roč. 53, č. 3 (2004), s. 305-310 ISSN 0862-8408 R&D Projects: GA ČR GA303/03/0799; GA MŠk OC 918.50 Institutional research plan: CEZ:AV0Z5011922 Keywords : mitochondrial glycerophosphate dehydrogenace * triiodothyronine * hydrogen peroxide Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition Impact factor: 1.140, year: 2004

Hydrogen peroxide removal with magnetically responsive Saccharomyces cerevisiae cells

Czech Academy of Sciences Publication Activity Database

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

Hydrogen peroxide in exhaled air of healthy children: reference values

NARCIS (Netherlands)

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

1998-01-01

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

21 CFR 172.167 - Silver nitrate and hydrogen peroxide solution.

Science.gov (United States)

2010-04-01

... SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.167 Silver nitrate and hydrogen peroxide solution... intended to be filtered through a silver-containing water filter. (g) Bottled water must meet the quality...

Fully-reversible optical sensor for hydrogen peroxide with fast response.

Science.gov (United States)

Ding, Longjiang; Chen, Siyu; Zhang, Wei; Zhang, Yinglu; Wang, Xu-Dong

2018-05-09

A fully reversible optical sensor for hydrogen peroxide with fast response is presented. The sensor was fabricated by in-situ growing ultra-small platinum nanoparticles (PtNPs) inside the pores of fibrous silica particles (KCC-1). The nanocomposite was then embedded into a hydrogel matrix and form a sensor layer, the immobilized PtNPs can catalytically convert hydrogen peroxide into molecular oxygen, which is measured via luminescent quenching based oxygen sensor underneath. Owing to the high porosity and permeability of KCC-1 and high local concentration of PtNPs, the sensor exhibits fast response (less than 1 min) and full reversibility. The measurement range of the sensor covers 1.0 μM to 10.0 mM, and very small amount of sample is required during measurement (200 μL). Because of its high stability, excellent reversibility and selectivity, and extremely fast response, the sensor could fulfill all industry requirements for real-time measurement, and fill market vacancy.

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

International Nuclear Information System (INIS)

Christian, B.J.; Pugh, L.B.; Clarke, B.H.

1995-01-01

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)

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

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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

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

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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.

Hydrous Ferric Oxides in Sediment Catalyze Formation of Reactive Oxygen Species during Sulfide Oxidation

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Sarah A. Murphy

2016-11-01

Full Text Available Abstract: This article describes the formation of reactive oxygen species as a result of the oxidation of dissolved sulfide by Fe(III-containing sediments suspended in oxygenated seawater over the pH range 7.00 and 8.25. Sediment samples were obtained from across the coastal littoral zone in South Carolina, US, at locations from the beach edge to the forested edge of a Spartina dominated estuarine salt marsh and suspended in aerated seawater. Reactive oxygen species (superoxide and hydrogen peroxide production was initiated in sediment suspensions by the addition of sodium bisulfide. The subsequent loss of HS-, formation of Fe(II (as indicated by Ferrozine, and superoxide and hydrogen peroxide were monitored over time. The concentration of superoxide rose from the baseline and then persisted at an apparent steady state concentration of approximately 500 nanomolar at pH 8.25 and 200 nanomolar at pH 7.00 respectively until >97% hydrogen sulfide was consumed. Measured superoxide was used to predict hydrogen peroxide yield based on superoxide dismutation. Dismutation alone quantitatively predicted hydrogen peroxide formation at pH 8.25 but over predicted hydrogen peroxide formation at pH 7 by a factor of approximately 102. Experiments conducted with episodic spikes of added hydrogen peroxide indicated rapid hydrogen peroxide consumption could account for its apparent low instantaneous yield, presumably the result of its reaction with Fe(II species, polysulfides or bisulfite. All sediment samples were characterized for total Fe, Cu, Mn, Ni, Co and hydrous ferric oxide by acid extraction followed by mass spectrometric or spectroscopic characterization. Sediments with the highest loadings of hydrous ferric oxide were the only sediments that produced significant dissolved Fe(II species or ROS as a result of sulfide exposure.

Oxidative desulphurization study of gasoline and kerosene. Role of some organic and inorganic oxidants

Energy Technology Data Exchange (ETDEWEB)

Shakirullah, M.; Ahmad, Waqas; Ahmad, Imtiaz; Ishaq, M.

2010-11-15

Desulphurization of gasoline and kerosene was carried out using organic and inorganic oxidants. Among the organic oxidants used were hydrogen peroxide in combination with acetic acid, formic acid, benzoic acid and butyric acid, while inorganic oxidants used included potassium permanganate and sodium perchlorate. The oxidation of each petroleum oil was carried out in two steps; the first step consisted of oxidation of the feed at moderate temperature and atmospheric pressure while in the second step, the oxidized mixture was extracted with azeotropic mixture of acetonitrile-water. A maximum desulphurization has occurred with NaClO{sub 4} and hydrogen peroxide and acetic acid, which are 68% and 61%, respectively in case of gasoline and 66% and 63%, respectively in case of kerosene oil. The FTIR study of the whole and variously desulphurized gasoline and kerosene was also carried out. The results indicate considerable desulphurization by absence of bands that corresponds to sulphur moieties in NaClO{sub 4} and hydrogen peroxide treated samples. (author)

Green hypergolic combination: Diethylenetriamine-based fuel and hydrogen peroxide

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Kang, Hongjae; Kwon, Sejin

2017-08-01

The present research dealt with the concept of green hypergolic combination to replace the toxic hypergolic combinations. Hydrogen peroxide was selected as a green oxidizer. A novel recipe for the non-toxic hypergolic fuel (Stock 3) was suggested. Sodium borohydride was blended into the mixture of energetic hydrocarbon solvents as an ignition source for hypergolic ignition. The main ingredient of the mixture was diethylenetriamine. By mixing some amount of tetrahydrofuran with diethylenetriamine, the mixture became more flammable and volatile. The mixture of Stock 3 fuel remained stable for four months in the lab scale storability test. Through a simple drop test, the hypergolicity of the green hypergolic combination was verified. Comparing to the toxic hypergolic combination MMH/NTO as the reference, the theoretical performance of the green hypergolic combination would be achieved about 96.7% of the equilibrium specific impulse and about 105.7% of the density specific impulse. The applicability of the green hypergolic combination was successfully confirmed through the static hot-fire tests using 500 N scale hypergolic thruster.

Development of a green bipropellant hydrogen peroxide thruster for attitude control on satellites

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Woschnak, A.; Krejci, D.; Schiebl, M.; Scharlemann, C.

2013-03-01

This document describes the selection assessment of propellants for a 1-newton green bipropellant thruster for attitude control on satellites. The development of this thruster was conducted as a part of the project GRASP (Green Advanced Space Propellants) within the European FP7 research program. The green propellant combinations hydrogen peroxide (highly concentrated with 87.5 %(wt.)) with kerosene or hydrogen peroxide (87.5 %(wt.)) with ethanol were identified as interesting candidates and were investigated in detail with the help of an experimental combustion chamber in the chemical propulsion laboratory at the Forschungsund Technologietransfer GmbH ― Fotec. Based on the test results, a final selection of propellants was performed.

Phytoproteins in green leaves as building blocks for photosynthesis of gold nanoparticles: An efficient electrocatalyst towards the oxidation of ascorbic acid and the reduction of hydrogen peroxide.

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Megarajan, Sengan; Ayaz Ahmed, Khan Behlol; Rajendra Kumar Reddy, G; Suresh Kumar, P; Anbazhagan, Veerappan

2016-02-01

Herein, we present a simple and green method for the synthesis of gold nanoparticles (AuNPs) using the phytoproteins of spinach leaves. Under ambient sunlight irradiation, the isolated phytoprotein complex from spinach leaves reduces the gold chloride aqueous solution and stabilizes the formed AuNPs. As prepared nanoparticles were characterized by UV-visible spectroscopy, Fourier transform infra-red (FTIR) spectroscopy, zeta potential, transmission electron microscopy (TEM) and energy dispersive X-ray analysis (EDS). The surface plasmon resonance (SPR) maximum for AuNPs was observed at 520 nm. The zeta potential value estimated for the AuNPs is -27.0 mV, indicating that the NPs are well separated. Transmission electron micrographs revealed that the particles are spherical in nature with the size range from 10 to 15 nm. AuNPs act as a catalyst in the degradation of an azo dye, methyl orange in an aqueous environment. The reduction rate was determined to be pseudo-first order. Electrocatalytic efficiency of the synthesized AuNPs via this green approach was studied by chronoamperometry using ascorbic acid and hydrogen peroxide as a model compound for oxidation and reduction, respectively. Electrocatalytic studies indicate that the gold nanoparticles can be used to detect ascorbic acid and hydrogen peroxide in micromolar concentrations with response time less than 3s. Copyright © 2015 Elsevier B.V. All rights reserved.

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

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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.

Apricot melanoidins prevent oxidative endothelial cell death by counteracting mitochondrial oxidation and membrane depolarization.

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Annalisa Cossu

Full Text Available The cardiovascular benefits associated with diets rich in fruit and vegetables are thought to be due to phytochemicals contained in fresh plant material. However, whether processed plant foods provide the same benefits as unprocessed ones is an open question. Melanoidins from heat-processed apricots were isolated and their presence confirmed by colorimetric analysis and browning index. Oxidative injury of endothelial cells (ECs is the key step for the onset and progression of cardiovascular diseases (CVD, therefore the potential protective effect of apricot melanoidins on hydrogen peroxide-induced oxidative mitochondrial damage and cell death was explored in human ECs. The redox state of cytoplasmic and mitochondrial compartments was detected by using the redox-sensitive, fluorescent protein (roGFP, while the mitochondrial membrane potential (MMP was assessed with the fluorescent dye, JC-1. ECs exposure to hydrogen peroxide, dose-dependently induced mitochondrial and cytoplasmic oxidation. Additionally detected hydrogen peroxide-induced phenomena were MMP dissipation and ECs death. Pretreatment of ECs with apricot melanoidins, significantly counteracted and ultimately abolished hydrogen peroxide-induced intracellular oxidation, mitochondrial depolarization and cell death. In this regard, our current results clearly indicate that melanoidins derived from heat-processed apricots, protect human ECs against oxidative stress.

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

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

2010-10-21

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

Increased exhalation of hydrogen peroxide in healthy subjects following cigarette consumption

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Sandra Baltazar Guatura

2000-07-01

Full Text Available CONTEXT: Increased hydrogen peroxide has been described in the expired breath condensate (H2O2-E of several lung conditions, such as acute respiratory distress syndrome, chronic obstructive pulmonary disease and asthma. This technique has been advocated as being a simple method for documenting airway inflammation. OBJECTIVE: To evaluate H2O2-E in healthy cigarette smokers, and to determine the acute effects of the consumption of one cigarette on H2O2-E levels. TYPE OF STUDY: Prospective, controlled trial. SETTING: A pulmonary function laboratory in a University Hospital. PARTICIPANTS: Two groups of healthy volunteers: individuals who had never smoked (NS; n=10; 4 men; age = 30.6 ± 6.2 years and current cigarette smokers (S; n=12; 7 men; age = 38.7 ± 9.8. None of the volunteers had respiratory symptoms and all showed normal spirometric tests. INTERVENTION: Expired air was collected from all volunteers through a face mask and a plastic collecting system leading into a flask with dry ice and pure ethanol. Samples from the group S were collected twice, before and half an hour after the combustion of one cigarette. MAIN MEASUREMENTS: Expired hydrogen peroxide using the Gallati and Pracht method. RESULTS: The S and NS groups showed comparable levels of H2O2-E at basal conditions [NS = 0.74 muM (DP 0.24 vs. S = 0.75 muM (DP 0.31]. The smokers showed a significant increase in H2O2-E levels half an hour after the consumption of only one cigarette [0.75 muM (DP 0.31 vs. 0.95 muM (DP 0.22]. CONCLUSION: The present results are consistent with the concept that smokers increase oxidative stress with elevated production of reactive oxygen species, contributing to the development of smoking-related disorders.

Oxidation and detoxification of trivalent arsenic species

International Nuclear Information System (INIS)

Aposhian, H. Vasken; Zakharyan, Robert A.; Avram, Mihaela D.; Kopplin, Michael J.; Wollenberg, Michael L.

2003-01-01

Arsenic compounds with a +3 oxidation state are more toxic than analogous compounds with a +5 oxidation state, for example, arsenite versus arsenate, monomethylarsonous acid (MMA III ) versus monomethylarsonic acid (MMA V ), and dimethylarsinous acid (DMA III ) versus dimethylarsinic acid (DMA V ). It is no longer believed that the methylation of arsenite is the beginning of a methylation-mediated detoxication pathway. The oxidation of these +3 compounds to their less toxic +5 analogs by hydrogen peroxide needs investigation and consideration as a potential mechanism for detoxification. Xanthine oxidase uses oxygen to oxidize hypoxanthine to xanthine to uric acid. Hydrogen peroxide and reactive oxygen are also products. The oxidation of +3 arsenicals by the hydrogen peroxide produced in the xanthine oxidase reaction was blocked by catalase or allopurinol but not by scavengers of the hydroxy radical, e.g., mannitol or potassium iodide. Melatonin, the singlet oxygen radical scavenger, did not inhibit the oxidation. The production of H 2 O 2 by xanthine oxidase may be an important route for decreasing the toxicity of trivalent arsenic species by oxidizing them to their less toxic pentavalent analogs. In addition, there are many other reactions that produce hydrogen peroxide in the cell. Although chemists have used hydrogen peroxide for the oxidation of arsenite to arsenate to purify water, we are not aware of any published account of its potential importance in the detoxification of trivalent arsenicals in biological systems. At present, this oxidation of the +3 oxidation state arsenicals is based on evidence from in vitro experiments. In vivo experiments are needed to substantiate the role and importance of H 2 O 2 in arsenic detoxication in mammals

Evaluating the Effect of Seed Treatment with Hydrogen Peroxide on Anatomical and Physiological Characteristics of Wheat under Dry Condition

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T Jafarian

2017-12-01

Full Text Available Introduction Water deficit is the major abiotic factor limiting plant growth and crop productivity around the world. In all agricultural regions, yields of rain-fed crops are periodically reduced by drought. Among various strategies, pre-sowing treatment and priming of seeds are easy, low cost, low risk and effective approaches to overcome the environmental stress problems. Various priming strategies include osmopriming, halopriming, hormonal priming or hydropriming, etc. Hydrogen peroxide, a stress signal molecule, was evaluated as seed treatment to produce the metabolic changes, which could lead to improved drought tolerance in wheat. The interaction of signals conferring stress tolerance in accomplishing better crop growth and yield is a priority area of research. Here we report some anatomical, physiological and biochemical changes induced by Hydrogen peroxide during seed treatment and their involvement in conferring drought tolerance upon wheat. Materials and Methods A field study was conducted out at the research farm of agricultural collage of Ilam university during 2014-2015 cropping season. This study was aimed to investigate the priming seed with hydrogen peroxide on two wheat genotypes (Cross Sabalan (bread wheat and Saji (durum wheat, under dryland farming system condition. Experimental design was factorial, arranged in randomized complete block, with three replications. Two main factors were wheat genotypes and four soaking treatments of seeds with different concentration (zero, 25, 50 and 80 Mm of Hydrogen Peroxide. Seeds of each genotype were sown at 6 rows of 3 m length with lines space of 20 cm in depth 5 cm. At heading stage physiological traits were measured on selected leaves and then samples were taken to determine leaf area, Leaf rolling, number and length of Stomata on the epidermis, RWC, electrolyte leakage, photosynthetic pigments concentrations (Chla, b and carotenoid and antioxidant enzyme contents (catalase, ascorbate

Construction of a horseradish peroxidase resistant toward hydrogen peroxide by saturation mutagenesis.

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Asad, Sedigheh; Dastgheib, Seyed Mohammad Mehdi; Khajeh, Khosro

2016-11-01

Horseradish peroxidase (HRP) with a variety of potential biotechnological applications is still isolated from the horseradish root as a mixture of different isoenzymes with different biochemical properties. There is an increasing demand for preparations of high amounts of pure enzyme but its recombinant production is limited because of the lack of glycosylation in Escherichia coli and different glycosylation patterns in yeasts which affects its stability parameters. The goal of this study was to increase the stability of non-glycosylated enzyme, which is produced in E. coli, toward hydrogen peroxide via mutagenesis. Asparagine 268, one of the N-glycosylation sites of the enzyme, has been mutated via saturation mutagenesis using the megaprimer method. Modification and miniaturization of previously described protocols enabled screening of a library propagated in E. coli XJb (DE3). The library of mutants was screened for stability toward hydrogen peroxide with azinobis (ethylbenzthiazoline sulfonate) as a reducing substrate. Asn268Gly mutant, the top variant from the screening, exhibited 18-fold increased stability toward hydrogen peroxide and twice improved thermal stability compared with the recombinant HRP. Moreover, the substitution led to 2.5-fold improvement in the catalytic efficiency with phenol/4-aminoantipyrine. Constructed mutant represents a stable biocatalyst, which may find use in medical diagnostics, biosensing, and bioprocesses. © 2015 International Union of Biochemistry and Molecular Biology, Inc.

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

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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.

Oxidation resistant peroxide cross-linked UHMWPE produced by blending and surface diffusion

International Nuclear Information System (INIS)

Gul, Rizwan M; Oral, Ebru; Muratoglu, Orhun K

2014-01-01

Ultra-high molecular weight polyethylene (UHMWPE) has been widely used as acetabular cup in total hip replacement (THR) and tibial component in total knee replacement (TKR). Crosslinking of UHMWPE has been successful used to improve its wear performance leading to longer life of orthopedic implants. Crosslinking can be performed by radiation or organic peroxides. Peroxide crosslinking is a convenient process as it does not require specialized equipment and the level of crosslinking can be manipulated by changing the amount of peroxide added. However, there is concern about the long-term stability of these materials due to possible presence of by-products. Vitamin E has been successfully used to promote long-term oxidative stability of UHMWPE. In this study, UHMWPE has been crosslinked using organic peroxide in the presence of Vitamin E to produce an oxidation resistant peroxide crosslinked material. Crosslinking was performed both in bulk by mixing peroxide and resin, and only on the surface using diffusion of peroxides.The results show that UHMWPE can be crosslinked using organic peroxides in the presence of vitamin E by both methods. However, the level of crosslinking decreases with the increase in vitamin E content. The wear resistance increases with the increase in crosslink density, and oxidation resistance significantly increases due to the presence of vitamin E

Oxidation resistant peroxide cross-linked UHMWPE produced by blending and surface diffusion

International Nuclear Information System (INIS)

Gul, R. M.; Oral, E.; Muratoglu, O. K.

2013-01-01

Ultra-high molecular weight polyethylene (UHMWPE) has been widely used as acetabular cup in total hip replacement (THR) and tibial component in total knee replacement (TKR). Crosslinking of UHMWPE has been successful used to improve its wear performance leading to longer life of orthopedic implants. Crosslinking can be performed by radiation or organic peroxides. Peroxide crosslinking is a convenient process as it does not require specialized equipment and the level of crosslinking can be manipulated by changing the amount of peroxide added. However, there is concern about the long-term stability of these materials due to possible presence of by-products. Vitamin E has been successfully used to promote long-term oxidative stability of UHMWPE. In this study, UHMWPE has been crosslinked using organic peroxide in the presence of Vitamin E to produce an oxidation resistant peroxide crosslinked material. Crosslinking was performed both in bulk by mixing peroxide and resin, and only on the surface using diffusion of peroxides.The results show that UHMWPE can be crosslinked using organic peroxides in the presence of vitamin E by both methods. However, the level of crosslinking decreases with the increase in vitamin E content. The wear resistance increases with the increase in crosslink density, and oxidation resistance significantly increases due to the presence of vitamin E. (author)

Formation of Hydrogen Peroxide by Electrochemical Reduction of Molecular Oxygen using Luminol Chemiluminescence

International Nuclear Information System (INIS)

Rana, Sohail

2005-01-01

Formation of hydrogen peroxide by electrochemical reduction of molecular oxygen was examined by measuring luminol chemiluminescence and absorption spectrum using flow-injection method. Ferryl porphyrin is widely accepted as responsible species to stimulate the emission in hydrogen peroxide/ iron porphyrin/ luminol system. Emission was observed under cathodic potentials (0.05V at pH2.0 and -0.3V at pH11.0) by the electrochemical reduction of aerated electrolytes solution but emission was observed at anodic potentials. Iron porphyrin solution was added at down stream of the working electrode and was essential for the emission. Removal of the dissolved molecular oxygen resulted in the decrease of emission intensity by more than 70%. In order to examine the life time of reduced active species, delay tubes were introduced between working electrode Fe TMPyP inlet. Experimental results suggested the active species were stable for quite a long period. The emission was quenched considerably (>90%) when hydroperoxy was added at the down stream of working electrode whereas the Superoxide dismutase (SOD) had little effect and mannitol had no effect. The spectra at reduction potential under aerated condition were shifted to the longer wavelength (>430nm) compared to the original spectrum of Fe TMPyP (422nm), indicating that the ferryl species were mixed to some extent. These observations lead to the conclusion that hydrogen peroxide was produced first by electrochemical reduction of molecular oxygen which then converted Fe TMPyP into O=FeTMPyP to activate luminol. Comparing emission intensities with the reference experiments, the current efficiencies for the formation of hydrogen peroxide were estimated as about 30-65% in all over the pH range used. (author)

Massive Cerebral Gas Embolism under Discectomy due to Hydrogen Peroxide Irrigation

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Junjie Zhang

2015-01-01

Full Text Available Massive cerebral and spinal gas embolism occurs rarely as a complication of discectomy. We report a 54-year-old female who had undergone a discectomy (L3/4 and L4/5 under epidural anesthesia in a local hospital developed multiple massive gas embolisms. At closure, surgeons irrigated the incision wound with hydrogen peroxide. Soon after the irrigation, the patient suddenly developed tachycardia, hypotension, and rapid oxygen desaturation. Subsequently, patient progressed into unconsciousness and right hemianopsia quadriplegia. Computed tomography (CT scan showed multiple hypointensity spots around the brain due to cerebral gas embolism, which indicated the pneumoencephalos. The likely mechanism was the absorption of hydrogen peroxide into blood. When the amount of oxygen evolved exceeded its maximal blood solubility, venous embolization occurred. Though the patient was treated with supportive treatments and hyperbaric oxygen, she did not get full recovery and was left with severe long-term cerebral injury.

Mathematical modeling of static layer crystallization for propellant grade hydrogen peroxide

Science.gov (United States)

Hao, Lin; Chen, Xinghua; Sun, Yaozhou; Liu, Yangyang; Li, Shuai; Zhang, Mengqian

2017-07-01

Hydrogen peroxide (H2O2) is an important raw material widely used in many fields. In this work a mathematical model of heat conduction with a moving boundary was proposed to study the melt crystallization process of hydrogen peroxide which was carried out outside a cylindrical crystallizer. Considering the effects of the temperature of the cooling fluid on the thermal conductivity of crude crystal, the model is an improvement of Guardani's research and can be solved by analytic iteration method. An experiment was designed to measure the thickness of crystal layer with time under different conditions. A series of analysis, including the effects of different refrigerant temperature on crystal growth rate, the effects of different cooling rates on crystal layer growth rate, the effects of crystallization temperature on heat transfer and the model's application scope were conducted based on the comparison between experimental results and simulation results of the model.

Effectiveness of Vaporous Hydrogen Peroxide for the Decontamination of Representative Military Materials

National Research Council Canada - National Science Library

Dutt, D. L; Turetsky, A. L; Brickhouse, M; Pfarr, J. W; McVey, I. F; Meilander, S. L; Janick, A. J; Schulte, S. L; Dallmier, A. W

2004-01-01

.... While many chemical decontamination methods, including aqueous hydrogen peroxide, have been used or are under development for direct application, few vaporous methods are being evaluated for decontamination efficacy (McDonnell, G. et al., 2002...

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

Energy Technology Data Exchange (ETDEWEB)

Ortega-Gomez, E. [Department of Chemical Engineering, University of Almeria, 04120 Almeria (Spain); CIESOL, Joint Centre of the University of Almeria-CIEMAT, 04120 Almeria (Spain); Moreno Ubeda, J.C. [Department of Language and Computation, University of Almeria, 04120 Almeria (Spain); Alvarez Hervas, J.D. [Department of Language and Computation, University of Almeria, 04120 Almeria (Spain); Department of Language and Computation, University of Sevilla, 41092 Sevilla (Spain); Casas Lopez, J.L.; Santos-Juanes Jorda, L. [Department of Chemical Engineering, University of Almeria, 04120 Almeria (Spain); CIESOL, Joint Centre of the University of Almeria-CIEMAT, 04120 Almeria (Spain); Sanchez Perez, J.A., E-mail: jsanchez@ual.es [Department of Chemical Engineering, University of Almeria, 04120 Almeria (Spain); CIESOL, Joint Centre of the University of Almeria-CIEMAT, 04120 Almeria (Spain)

2012-10-30

Highlights: Black-Right-Pointing-Pointer Dissolved oxygen monitoring is used for automatic dosage of H{sub 2}O{sub 2} in photo-Fenton. Black-Right-Pointing-Pointer PI with anti-windup minimises H{sub 2}O{sub 2} consumption. Black-Right-Pointing-Pointer The H{sub 2}O{sub 2} consumption was reduced up to 50% with respect to manual addition strategies. Black-Right-Pointing-Pointer Appropriate H{sub 2}O{sub 2} dosage is achieved by PI with anti-windup under disturbances. - Abstract: The solar photo-Fenton process is widely used for the elimination of pollutants in aqueous effluent and, as such, is amply cited in the literature. In this process, hydrogen peroxide represents the highest operational cost. Up until now, manual dosing of H{sub 2}O{sub 2} has led to low process performance. Consequently, there is a need to automate the hydrogen peroxide dosage for use in industrial applications. As it has been demonstrated that a relationship exists between dissolved oxygen (DO) concentration and hydrogen peroxide consumption, DO can be used as a variable in optimising the hydrogen peroxide dosage. For this purpose, a model was experimentally obtained linking the dynamic behaviour of DO to hydrogen peroxide consumption. Following this, a control system was developed based on this model. This control system - a proportional and integral controller (PI) with an anti-windup mechanism - has been tested experimentally. The assays were carried out in a pilot plant under sunlight conditions and with paracetamol used as the model pollutant. In comparison with non-assisted addition methods (a sole initial or continuous addition), a decrease of 50% in hydrogen peroxide consumption was achieved when the automatic controller was used, driving an economic saving and an improvement in process efficiency.

Field-controlled electron transfer and reaction kinetics of the biological catalytic system of microperoxidase-11 and hydrogen peroxide

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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.

Nitrogen-Rich Polyacrylonitrile-Based Graphitic Carbons for Hydrogen Peroxide Sensing

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Brandon Pollack

2017-10-01

Full Text Available Catalytic substrate, which is devoid of expensive noble metals and enzymes for hydrogen peroxide (H2O2, reduction reactions can be obtained via nitrogen doping of graphite. Here, we report a facile fabrication method for obtaining such nitrogen doped graphitized carbon using polyacrylonitrile (PAN mats and its use in H2O2 sensing. A high degree of graphitization was obtained with a mechanical treatment of the PAN fibers embedded with carbon nanotubes (CNT prior to the pyrolysis step. The electrochemical testing showed a limit of detection (LOD 0.609 µM and sensitivity of 2.54 µA cm−2 mM−1. The promising sensing performance of the developed carbon electrodes can be attributed to the presence of high content of pyridinic and graphitic nitrogens in the pyrolytic carbons, as confirmed by X-ray photoelectron spectroscopy. The reported results suggest that, despite their simple fabrication, the hydrogen peroxide sensors developed from pyrolytic carbon nanofibers are comparable with their sophisticated nitrogen-doped graphene counterparts.

Photochemistry of peroxoborates: borate inhibition of the photodecomposition of hydrogen peroxide.

Science.gov (United States)

Rey, Sébastien; Davies, D Martin

2006-12-13

The UV absorbance and photochemical decomposition kinetics of hydrogen peroxide in borate/boric acid buffers were investigated as a function of pH, total peroxide concentration, and total boron concentration. At higher pH borate/boric acid inhibits the photodecomposition of hydrogen peroxide (molar absorptivity and quantum yield of H(2)O(2) and HO(2) (-), (19.0+/-0.3) M(-1) cm(-1) and 1, and (237+/-7) M(-1) cm(-1) and 0.8+/-0.1, respectively). The results are consistent with the equilibrium formation of the anions monoperoxoborate, K(BOOH)=[H(+)][HOOB(OH)(3) (-)]/([B(OH)(3)][H(2)O(2)]), 2.0 x 10(-8), R. Pizer, C. Tihal, Inorg. Chem. 1987, 26, 3639-3642, and monoperoxodiborate, K(BOOB)=[BOOB(2-)]/([B(OH)(4) (-)][HOOB(OH)(3) (-)]), 1.0+/-0.3 or 4.3+/-0.9, depending upon the conditions, with molar absorptivity, (19+/-1) M(-1) cm(-1) and (86+/-15) M(-1) cm(-1), respectively, and respective quantum yields, 1.1+/-0.1 and 0.04+/-0.04. The low quantum yield of monoperoxodiborate is discussed in terms of the slower diffusion apart of incipient (.)OB(OH)(3) (-) radicals than may be possible for (.)OH radicals, or a possible oxygen-bridged cyclic structure of the monoperoxodiborate.

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

Directory of Open Access Journals (Sweden)

Nancy L Martin

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

Can Melatonin Act as an Antioxidant in Hydrogen Peroxide-Induced Oxidative Stress Model in Human Peripheral Blood Mononuclear Cells?

Directory of Open Access Journals (Sweden)

Solaleh Emamgholipour

2016-01-01

Full Text Available Purpose. We aimed to investigate the possible effects of melatonin on gene expressions and activities of MnSOD and catalase under conditions of oxidative stress induced by hydrogen peroxide (H2O2 in peripheral blood mononuclear cells (PBMCs. Materials and Methods. PBMCs were isolated from healthy subjects and treated as follows: (1 control (only with 0.1% DMSO for 12 h; (2 melatonin (1 mM for 12 h; (3 H2O2 (250 μM for 2 h; (4 H2O2 (250 μM for 2 h following 10 h pretreatment with melatonin (1 mM. The gene expression was evaluated by real-time PCR. MnSOD and catalase activities in PBMCs were determined by colorimetric assays. Results. Pretreatment of PBMCs with melatonin significantly augmented expression and activity of MnSOD which were diminished by H2O2. Melatonin treatment of PBMCs caused a significant upregulation of catalase by almost 2-fold in comparison with untreated cells. However, activity and expression of catalase increased by 1.5-fold in PBMCs under H2O2-induced oxidative stress compared with untreated cell. Moreover, pretreatment of PBMCs with melatonin resulted in a significant 1.8-fold increase in catalase expression compared to PBMCs treated only with H2O2. Conclusion. It seems that melatonin could prevent from undesirable impacts of H2O2-induced oxidative stress on MnSOD downregulation. Moreover, melatonin could promote inductive effect of H2O2 on catalase mRNA expression.

Production of uranium peroxide

International Nuclear Information System (INIS)

Caropreso, F.E.; Kreuz, D.F.

1977-01-01

A process is claimed of recovering uranium values as uranium peroxide from an aqueous uranyl solution containing dissolved vanadium and sodium impurities by treating the uranyl solution with hydrogen peroxide in an amount sufficient to have an excess of at least 0.5 parts H 2 O 2 per part of vanadium (V 2 O 5 ) above the stoichiometric amount required to form the uranium peroxide, the hydrogen peroxide treatment is carried out in three sequential phases consisting of I, 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 medium maintained in the range of 2.5 to 5.5 for a period of from about 1 to 60 minutes after the hydrogen peroxide addition; II, 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 about 5 to 180 minutes and III, a final phase in which the pH of the reaction medium is maintained in the range of 4.0 to 7.0 for a period of about 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 is maintained during the entire treatment up until the uranium peroxide is separated from the reaction medium

Efficacy of formalin, hydrogen-peroxide, and sodium-chloride on fungal-infected rainbow-trout eggs

Science.gov (United States)

Schreier, Theresa M.; Rach, J.J.; Howe, G.E.

1996-01-01

Antifungal agents are essential for the maintenance of healthy stocks of fish and their eggs in intensive aquaculture operations. In the usa, formalin is the only fungicide approved for use in fish culture, however, hydrogen peroxide and sodium chloride have been granted low regulatory priority drug status by the united states food and drug administration (fda) and their use is allowed. We evaluated the efficacy of these fungicides for controlling fungal infections on rainbow trout eggs. A pilot study was conducted to determine the minimum water flow rate required to administer test chemicals accurately in heath incubators. A minimum water flow rate of 7.6 1 min(-1) was necessary to maintain treatment concentrations during flow-through chemical exposures, the antifungal activity of formalin, hydrogen peroxide, and sodium chloride was evaluated by treating uninfected and 10% fungal-infected (saprolegnia parasitica) rainbow trout eggs (oncorhynchus mykiss) for 15 min every other day until hatch. There were no significant differences among treatments in percent hatch or final infection for uninfected eggs receiving prophylactic chemical treatments, eggs of the negative control group (uninfected and untreated) had a mean hatch exceeding 86%, all chemical treatments conducted on the infected egg groups controlled the spread of fungus and improved hatching success compared with the positive control groups (infected and untreated), formalin treatments of 1000 and 1500 mu l 1(-1) and hydrogen peroxide treatments of 500 and 1000 mu l 1(-1) were the most effective. Sodium chloride treatments of 30000 mg 1(-1) improved fry hatch, but the compound was less effective at inhibiting fungal growths compared with hydrogen peroxide and formalin treatments.

Hypersensitivity of mouse NEIL1-knockdown cells to hydrogen peroxide during S phase

International Nuclear Information System (INIS)

Yamamoto, Ryohei; Ohshiro, Yukari; Shimotani, Tatsuhiko; Yamamoto, Mizuki; Matsuyama, Satoshi; Ide, Hiroshi; Kubo, Kihei

2014-01-01

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 (H 2 O 2 ) sensitivity. Hypersensitivity to H 2 O 2 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

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

Directory of Open Access Journals (Sweden)

Alberto Consolaro

2013-12-01

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

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

Science.gov (United States)

Consolaro, Alberto

2013-01-01

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

Vaporized Hydrogen Peroxide (VHP) Decontamination of a Section of a Boeing 747 Cabin

National Research Council Canada - National Science Library

Shaffstall, Robert M; Garner, Robert P; Bishop, Joshua; Cameron-Landis, Lora; Eddington, Donald L; Hau, Gwen; Spera, Shawn; Mielnik, Thaddeus; Thomas, James A

2006-01-01

The use of STERIS Corporation's Vaporized Hydrogen Peroxide (VHP)* technology as a potential biocide for aircraft decontamination was demonstrated in a cabin section of the Aircraft Environment Research Facility...

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

Directory of Open Access Journals (Sweden)

Zun Maria

2014-12-01

Full Text Available In this study, the stability of 10% hydrogen peroxide aqueous and non-aqueous solutions with the addition of 6% (w/w of urea was evaluated. The solutions were stored at 20°C, 30°C and 40°C, and the decomposition of hydrogen peroxide proceeded according to first-order kinetics. With the addition of the urea in the solutions, the decomposition rate constant increased and the activation energy decreased. The temperature of storage also affected the decomposition of substance, however, 10% hydrogen peroxide solutions prepared in PEG-300, and stabilized with the addition of 6% (w/w of urea had the best constancy.

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

Energy Technology Data Exchange (ETDEWEB)

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)

ENAMEL SUSCEPTIBILITY TO RED WINE STAINING AFTER 35% HYDROGEN PEROXIDE BLEACHING

Science.gov (United States)

Berger, Sandrine Bittencourt; Coelho, Alessandra Sanchez; Oliveira, Valéria Aparecida Pessatti; Cavalli, Vanessa; Giannini, Marcelo

2008-01-01

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. PMID:19089218

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

Directory of Open Access Journals (Sweden)

Sandrine Bittencourt Berger

2008-06-01

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

In-depth characterization of the fluorescent signal of HyPer, a probe for hydrogen peroxide, in bacteria exposed to external oxidative stress.

Science.gov (United States)

Lim, Joseph B; Barker, Kimberly A; Huang, Beijing K; Sikes, Hadley D

2014-11-01

Genetically encoded, fluorescent biosensors have been developed to probe the activities of various signaling molecules inside cells ranging from changes in intracellular ion concentrations to dynamics of lipid second messengers. HyPer is a member of this class of biosensors and is the first to dynamically respond to hydrogen peroxide (H2O2), a reactive oxygen species that functions as a signaling molecule. However, detailed characterization of HyPer's signal is not currently available within the context of bacteria exposed to external oxidative stress, which occurs in the immunological response of higher organisms against invasive pathogenic bacteria. Here, we performed this characterization, specifically in Escherichia coli exposed to external H2O2. We found that the temporal behavior of the signal does not correspond exactly to peroxide concentration in the system as a function of time and expression of the sensor decreases the peroxide scavenging activity of the cell. We also determined the effects of cell number, both before and after normalization of externally added H2O2 to the number of cells. Finally, we report quantitative characteristics of HyPer's signal in this context, including the dynamic range of the signal, the signal-to-noise ratio, and the half saturation constant. These parameters show statistically meaningful differences in signal between two commonly used strains of E. coli, demonstrating how signal can vary with strain. Taken together, our results establish a systematic, quantitative framework for researchers seeking to better understand the role of H2O2 in the immunological response against bacteria, and for understanding potential differences in the details of HyPer's quantitative performance across studies. Copyright © 2014 Elsevier B.V. All rights reserved.

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

Science.gov (United States)

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

Organo-bridged silsesquioxane titanates for heterogeneous catalytic epoxidation with aqueous hydrogen peroxide

NARCIS (Netherlands)

Wang, Y.M.; Magusin, P.C.M.M.; Santen, van R.A.; Abbenhuis, H.C.L.

2007-01-01

Organo-bridged silsesquioxane titanates for heterogeneous catalytic epoxidation with aqueous hydrogen peroxide were synthesized through the acid-catalyzed hydrolysis and co-condensation of organotrialkoxysilane monomers and a,¿-bis(trialkoxysilyl) alkane cross-linkers in ethanol–water solution, with

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

Energy Technology Data Exchange (ETDEWEB)

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

1998-12-31

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

γ-Tocotrienol does not substantially protect DS neurons from hydrogen peroxide-induced oxidative injury

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Then Sue-Mian

2012-01-01

Full Text Available Abstract Background Down syndrome (DS neurons are more susceptible to oxidative stress and previous studies have shown that vitamin E was able to reduce oxidative stress and improve DS neurons' viability. Therefore, this study was done to investigate the protective role of γ-tocotrienol (γT3 in DS neurons from hydrogen peroxide (H2O2 -induced oxidative stress. The pro-apoptosis tendency of γT3 was compared to α-tocopherol (αT in non-stress condition as well. Methods Primary culture of DS and euploid neurons were divided into six groups of treatment: control, H2O2, γT3 pre-treatment with H2O2, γT3 only, αT pre-treatment with H2O2 and αT only. The treatments were assessed by MTS assay and apoptosis assay by single-stranded DNA (ssDNA apoptosis ELISA assay, Hoechst and Neu-N immunofluorescence staining. The cellular uptake of γT3 and αT was determined by HPLC while protein expressions were determined by Western blot. Comparison between groups was made by the Student's t test, one-way ANOVA and Bonferroni adjustment as well as two-way ANOVA for multiple comparisons. Results One day incubation of γT3 was able to reduced apoptosis of DS neurons by 10%, however γT3 was cytotoxic at longer incubation period (14 days and at concentrations ≥ 100 μM. Pre-treatment of αT and γT3 only attenuate apoptosis and increase cell viability in H2O2-treated DS and euploid neurons by 10% in which the effects were minimal to maintain most of the DS cells' morphology. γT3 act as a free radical scavenger by reducing ROS generated by H2O2. In untreated controls, DS neurons showed lower Bcl-2/Bax ratio and p53 expression compared to normal neurons, while cPKC and PKC-δ expressions were higher in DS neurons. On the other hand, pre-treatment of γT3 in H2O2-treated DS neurons have reduced Bcl-2/Bax ratio, which was not shown in euploid neurons. This suggests that pre-treatment of γT3 did not promote DS cell survival. Meanwhile γT3 and αT treatments

Analysis of the Color and Fluorescence Alterations of Enamel and Dentin Treated With Hydrogen Peroxide.

Science.gov (United States)

Caneppele, Taciana Marco Ferraz; Rocha Gomes Torres, Carlos; Bresciani, Eduardo

2015-10-01

The aim of this study was to evaluate the effect of hydrogen peroxide whitening on fluorescence and color of bovine enamel and dentin. Twenty five dentin discs and 25 enamel discs, with 6 mm diameter and 1 mm thick, were obtained. Direct fluorescence (spectrofluorophotometry) and color (spectrophotometry) were assessed. After fluorescence and color baseline measurements, specimens were immersed in a 35% hydrogen peroxide (HP) solution for 1 h. This procedure was repeated after 7 days. Final fluorescence and color measurements were performed after the second immersion. Chemical characterization of 5 additional specimens was also performed. Data were submitted to repeated analysis of variance and Tukey's test for fluorescence and unpaired t-test for color and chemical components (pwhitening. Enamel presented lower fluorescence than dentin at baseline, but this parameter did not decrease after whitening. Color changes were observed for both substrates, with significantly greater whitening effect in dentin (ΔE=10.37) (pWhitening by hydrogen peroxide induced significant decrease in fluorescence of tooth dentin and promoted significant color changes in dentin and enamel with more accentuated outcomes in dentin.

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

Science.gov (United States)

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

2002-09-01

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

Formation of three-dimensional nano-porous silver films and application toward electrochemical detection of hydrogen peroxide

Energy Technology Data Exchange (ETDEWEB)

Fan, Junpeng [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Bian, Xiufang, E-mail: xfbian@sdu.edu.cn [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Niu, Yuchao [Department of Materials Science and Engineering, Shandong Jianzhu University, Fengming Road, Lingang Development Zone, Jinan 250101 (China); Bai, Yanwen; Xiao, Xinxin; Yang, Chuncheng; Yang, Jianfei; Yang, Jinyue [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061 (China)

2013-11-15

By using the chemically dealloying method, three-dimensional nano-porous silver films (3-D NPSFs) are fabricated into a novel sensor for detecting hydrogen peroxide. The precursor films are prepared by high vacuum magnetron co-sputtering. High-resolution transmission electron microscope (HRTEM) and scanning electron microscope (SEM) are taken to investigate the structure and the micro morphology of the precursor films and nano-porous films. We find that the precursor films are composed of glassy matrix and nanocrystallines. After dealloying, the films exhibit a combination of homogenously distributed pores and silver filaments, and exhibit an open, three dimensional bicontinuous interpenetrating ligament–channel structure. Thickness and morphology of the films can be easily controlled by the sputtering time and alloy composition of the precursor films, respectively. In addition, NPSFs show a good linear responding for the concentration of hydrogen peroxide in phosphate buffered solutions, which indicates NPSFs could be a promising electrochemical material for hydrogen peroxide detection.

Determination of Trace Anions in Concentrated Hydrogen Peroxide by Direct Injection Ion Chromatography with Conductivity Detection after Pt-Catalyzed On-Line Decomposition

International Nuclear Information System (INIS)

Kim, Do Hee; Lee, Bo Kyung; Lee, Dong Soo

1999-01-01

A method has been developed for the determination of trace anion impurities in concentrated hydrogen peroxide. The method involves on-line decomposition of hydrogen peroxide, ion chromatographic separation and subsequent suppressed-type conductivity detection. H 2 O 2 is decomposed in Pt-catalyst filled Gore-Tex membrane tubing and the resulting aqueous solution containing analytes is introduced to the injection valve of an ion chromatograph for periodic determinations. The oxygen gas evolving within the membrane tubing escapes freely through the membrane wall causing no problem in ion chromatographic analysis. Decomposition efficiency is above 99.99% at a flow rate of 0.4mL/min for a 30% hydrogen peroxide concentration. Analytes are quantitatively retained. The analysis results for several brands of commercial hydrogen peroxides are reported

Lycopene protects human SH-SY5Y neuroblastoma cells against hydrogen peroxide-induced death via inhibition of oxidative stress and mitochondria-associated apoptotic pathways

Science.gov (United States)

FENG, CHUNSHENG; LUO, TIANFEI; ZHANG, SHUYAN; LIU, KAI; ZHANG, YANHONG; LUO, YINAN; GE, PENGFEI

2016-01-01

Oxidative stress, which is characterized by excessive production of reactive oxygen species (ROS), is a common pathway that results in neuronal injury or death due to various types of pathological stress. Although lycopene has been identified as a potent antioxidant, its effect on hydrogen peroxide (H2O2)-induced neuronal damage remains unclear. In the present study, pretreatment with lycopene was observed to protect SH-SY5Y neuroblastoma cells against H2O2-induced death via inhibition of apoptosis resulting from activation of caspase-3 and translocation of apoptosis inducing factor (AIF) to the nucleus. Furthermore, the over-produced ROS, as well as the reduced activities of anti-oxidative enzymes, superoxide dismutase and catalase, were demonstrated to be alleviated by lycopene. Additionally, lycopene counteracted H2O2-induced mitochondrial dysfunction, which was evidenced by suppression of mitochondrial permeability transition pore opening, attenuation of the decline of the mitochondrial membrane potential, and inhibition of the increase of Bax and decrease of Bcl-2 levels within the mitochondria. The release of cytochrome c and AIF from the mitochondria was also reduced. These results indicate that lycopene is a potent neuroprotectant against apoptosis, oxidative stress and mitochondrial dysfunction, and could be administered to prevent neuronal injury or death. PMID:27035331

The influences of shape and structure of MnO2 nanomaterials over the non-enzymatic sensing ability of hydrogen peroxide

Science.gov (United States)

Babu, K. Justice; Zahoor, Awan; Nahm, Kee Suk; Ramachandran, R.; Rajan, M. A. Jothi; Gnana kumar, G.

2014-02-01

The different morphologies of MnO2 nanomaterials such as rod, belt, and flower were synthesized through a facile hydrothermal method, and their phases were also effectively controlled without employing any organic surfactants. The growth mechanisms of prepared nanostructures has been rationalized through the observed morphologic and structural characterizations. The prepared MnO2 nanostructures improved the electron transfer kinetics and minimized the overpotential and exhibited good electrocatalytic activities in detecting the hydrogen peroxide. Among the studied nanostructures, r-MnO2 exhibited an excellent sensing behavior toward hydrogen peroxide, and a linear current response was observed for the hydrogen peroxide, ranging from 1 micromolar to 1.5 mM with a high-sensitivity and low-level detection limit of 62.9 μAmM-1 cm-2 and 0.1 μM, respectively. Moreover, r-MnO2-modified electrode exhibited high selectivity toward hydrogen peroxide and interference-free phenomenon for the other electroactive species.

Treatment of portal venous gas embolism with hyperbaric oxygen after accidental ingestion of hydrogen peroxide: a case report and review of the literature.

Science.gov (United States)

Papafragkou, Sotirios; Gasparyan, Anna; Batista, Richard; Scott, Paul

2012-07-01

It is well known that hydrogen peroxide ingestion can cause gas embolism. To report a case illustrating that the definitive, most effective treatment for gas embolism is hyperbaric oxygen therapy. We present a case of a woman who presented to the Emergency Department with acute abdominal pain after an accidental ingestion of concentrated hydrogen peroxide. Complete recovery from her symptoms occurred quickly with hyperbaric oxygen therapy. This is a case report of the successful use of hyperbaric oxygen therapy to treat portal venous gas embolism caused by hydrogen peroxide ingestion. Hyperbaric oxygen therapy can be considered for the treatment of symptomatic hydrogen peroxide ingestion. Copyright © 2012 Elsevier Inc. All rights reserved.

Intestinal glutathione: determinant of mucosal peroxide transport, metabolism, and oxidative susceptibility

International Nuclear Information System (INIS)

Aw, Tak Yee

2005-01-01

The intestine is a primary site of nutrient absorption and a critical defense barrier against dietary-derived mutagens, carcinogens, and oxidants. Accumulation of oxidants like peroxidized lipids in the gut lumen can contribute to impairment of mucosal metabolic pathways, enterocyte dysfunction independent of cell injury, and development of gut pathologies, such as inflammation and cancer. Despite this recognition, we know little of the pathways of intestinal transport, metabolism, and luminal disposition of dietary peroxides in vivo or of the underlying mechanisms of lipid peroxide-induced genesis of intestinal disease processes. This chapter summarizes our current understanding of the determinants of intestinal absorption and metabolism of peroxidized lipids. I will review experimental evidence from our laboratory and others (Table 1) supporting the pivotal role that glutathione (GSH) and reduced nicotinamide adenine dinucleotide phosphate (NADPH) play in mucosal transport and metabolism of lipid hydroperoxides and how reductant availability can be compromised under chronic stress such as hypoxia, and the influence of GSH on oxidative susceptibility, and redox contribution to genesis of gut disorders. The discussion is pertinent to understanding dietary lipid peroxides and GSH redox balance in intestinal physiology and pathophysiology and the significance of luminal GSH in preserving the integrity of the intestinal epithelium

Major effect of hydrogen peroxide on bacterioplankton metabolism in the Northeast Atlantic.

Directory of Open Access Journals (Sweden)

Federico Baltar

Full Text Available Reactive oxygen species such as hydrogen peroxide have the potential to alter metabolic rates of marine prokaryotes, ultimately impacting the cycling and bioavailability of nutrients and carbon. We studied the influence of H2O2 on prokaryotic heterotrophic production (PHP and extracellular enzymatic activities (i.e., β-glucosidase [BGase], leucine aminopeptidase [LAPase] and alkaline phosphatase [APase] in the subtropical Atlantic. With increasing concentrations of H2O2 in the range of 100-1000 nM, LAPase, APase and BGase were reduced by up to 11, 23 and 62%, respectively, in the different water layers. Incubation experiments with subsurface waters revealed a strong inhibition of all measured enzymatic activities upon H2O2 amendments in the range of 10-500 nM after 24 h. H2O2 additions also reduced prokaryotic heterotrophic production by 36-100% compared to the rapid increases in production rates occurring in the unamended controls. Our results indicate that oxidative stress caused by H2O2 affects prokaryotic growth and hydrolysis of specific components of the organic matter pool. Thus, we suggest that oxidative stress may have important consequences on marine carbon and energy fluxes.

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

DEFF Research Database (Denmark)

Mielby, Jerrik Jørgen; Kegnæs, Søren

2013-01-01

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

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

NARCIS (Netherlands)

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

2013-01-01

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

Destruction kinetic of PCDDs/Fs in MSWI fly ash using microwave peroxide oxidation.

Science.gov (United States)

Chang, Yu-Min; Fang, Wen-Bin; Tsai, Kuo-Sheng; Kao, Jimmy C M; Lin, Kae-Long; Chen, Ching-Ho

2015-01-01

Microwave peroxide oxidation is a less greenhouse gas emission and energy-efficient technology to destroy toxic organic compounds in hazardous waste. The research novelty is to adopt the innovative microwave peroxide oxidation in H2SO4/HNO3 solution to efficiently destroy the polychlorinated dibenzo-p-dioxins (PCDDs)/Fs in municipal solid waste incineration fly ash. The major objective of this paper is to study dynamic destruction of PCDDs/Fs using the microwave peroxide oxidation. Almost all PCDDs/Fs in the raw fly ash can be destructed in 120 min at a temperature of 423 K using the microwave peroxide oxidation treatment. It was found that the microwave peroxide oxidation provides the potential to destruct the PCDDs/Fs content in municipal solid waste incinerator (MSWI) fly ash to a low level as a function of treatment time. A useful kinetic correlation between destruction efficiency and treatment conditions is proposed on the basis of the experimental data obtained in this study. The significance of this work in terms of practical engineering applications is that the necessary minimum treatment time can be solved using a proposed graphic illustration method, by which the minimum treatment time is obtained if the desired destruction efficiency and treatment temperature are known. Because of inorganic salt dissolution, the temperature would be a critical factor facilitating the parts of fly ash dissolution. Material loss problem caused by the microwave peroxide oxidation and the effects of treatment time and temperature are also discussed in this paper.

Antifungal efficacy of hydrogen peroxide in dental unit waterline disinfection.

Science.gov (United States)

Szymańska, Jolanta

2006-01-01

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

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

DEFF Research Database (Denmark)

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

2016-01-01

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......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...... 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...

Antibacterial effects of hydrogen peroxide and silver composition on selected pathogenic enterobacteriaceae

Directory of Open Access Journals (Sweden)

Mojtaba Davoudi

2012-01-01

Full Text Available Aims: Antibacterial effects of hydrogen peroxide and silver composition on selected pathogenic enterobacteriaceae was investigated in this study. Materials and Methods: The efficacy of 30 ppb silver in 0.3% hydrogen peroxide solution for inactivation of selected Enterobacteriaceae, including Escherichia coli, Proteus mirabilis, and Klebsiella pneumoniae was assessed for 72 hours in a designated nutrient broth medium and steel surface. The bactericidal growth ability was determined for each bacterium genus by the conventional colony count method and turbidimetry via an optical density (OD assay at 450 nm in a time interval of 24 hours. Results: Suspensions of K.pneumoniae, and P.mirabilis showed a significant OD reduction at three 24-hour intervals (CI = 0.95; P < 0.05, for both, along with blocked growth in a designated broth medium during 24 to 48 hours of exposure. The disinfectant was also significantly efficient for inactivating of the mentioned bacteria on steel surfaces after a 15-minute time exposure (CI = 0.95; P < 0.05. For E.coli, the OD decreased slightly during the initial exposure time, but increased after 24 hours. Viable E.coli cells were proved by colonies grown on the plate. A qualitative surface decontamination test showed that three pathogenic bacteria were inactivated significantly after disinfectant exposure (CI = 0.95, P < 0.05. Conclusions: In conclusion, a combination of hydrogen peroxide and silver ions was proposed as a strong disinfecting agent both in suspensions and on the surfaces against these three important human pathogens.

Synergism between hydrogen peroxide and seventeen acids against five agri-food-borne fungi and one yeast strain.

Science.gov (United States)

Martin, H; Maris, P

2012-12-01

The objective of this study was to evaluate fungicidal efficacy of hydrogen peroxide administered in combination with 17 mineral and organic acids authorized for use in the food industry. The assays were performed on a 96-well microplate using a microdilution technique based on the checkerboard titration method. The six selected strains (one yeast and five fungi) were reference strains and strains representative of contaminating fungi found in the food industry. Each synergistic hydrogen peroxide/acid combination found after fifteen minutes contact time at 20 °C in distilled water was then tested in conditions simulating four different use conditions. Twelve combinations were synergistic in distilled water, eleven of these remained synergistic with one or more of the four mineral and organic interfering substances selected. Hydrogen peroxide/formic acid combination remained effective against four strains and was never antagonistic against the other two fungi. Combinations with propionic acid and acetic acid stayed synergistic against two strains. Those with oxalic acid and lactic acid kept their synergism only against Candida albicans. No synergism was detected against Penicillium cyclopium. Synergistic combinations of disinfectants were revealed, among them the promising hydrogen peroxide/formic acid combination. A rapid screening method developed in our laboratory for bacteria was adapted to fungi and used to reveal the synergistic potential of disinfectants and/or sanitizers combinations. © 2012 The Society for Applied Microbiology.

Non-enzymatic hydrogen peroxide sensor using an electrode modified with iron pentacyanonitrosylferrate nanoparticles

International Nuclear Information System (INIS)

Razmi, H.; Mohammad-Rezaei, R.

2010-01-01

An electrochemical sensor was developed for determination of hydrogen peroxide (HP) based on a carbon ceramic electrode modified with iron pentacyanonitrosylferrate (FePCNF). The surface of an iron-doped CCE was derivatized in a solution of PCNF by cycling the electrode potential between -0. 2 and +1. 3 V for about 60 times. The morphology and the composition of the resulting electrode were characterized by scanning electron microscopy and Fourier transform infrared techniques. The electrode displayed excellent response to the electro-oxidation of HP which is linearly related to its concentration in the range from 0. 5 μM to 1300 μM. The detection limit is 0. 4 μM, and the sensitivity is 849 A M -1 cm -2 . The modified electrode was used to determination of HP in hair coloring creams as real samples. (author)

Evaluation of vaporized hydrogen peroxide, Citrox and pH neutral Ecasol for decontamination of an enclosed area: a pilot study.

LENUS (Irish Health Repository)

Galvin, S

2012-01-01

Hydrogen peroxide, Ecasol and Citrox aerosols were each tested for their ability to kill a range of nosocomial pathogens. Hydrogen peroxide had the broadest microbicidal activity but operational issues limit its use. Ecasol was effective against all micro-organisms, except Clostridium difficile, while Citrox aerosols were not effective against Gram-negative bacilli.

Fisetin inhibits TNF-α-induced inflammatory action and hydrogen peroxide-induced oxidative damage in human keratinocyte HaCaT cells through PI3K/AKT/Nrf-2-mediated heme oxygenase-1 expression.

Science.gov (United States)

Seo, Seung-Hee; Jeong, Gil-Saeng

2015-12-01

Oxidative skin damage and skin inflammation play key roles in the pathogenesis of skin-related diseases. Fisetin is a naturally occurring flavonoid abundantly found in several vegetables and fruits. Fisetin has been shown to exert various positive biological effects, such as anti-cancer, anti-proliferative, neuroprotective and anti-oxidative effects. In this study, we investigate the skin protective effects and anti-inflammatory properties of fisetin in hydrogen peroxide- and TNF-α-challenged human keratinocyte HaCaT cells. When HaCaT cells were treated with non-cytotoxic concentrations of fisetin (1-20μM), heme oxygenase (HO)-1 mRNA and protein expression increased in a dose-dependent manner. Furthermore, fisetin dose-dependently increased cell viability and reduced ROS production in hydrogen peroxide-treated HaCaT cells. Fisetin also inhibited the production of NO, PGE2 IL-1β, IL-6, expression of iNOS and COX-2, and activation of NF-κB in HaCaT cells treated with TNF-α. Fisetin induced Nrf2 translocation to the nuclei. HO-1 siRNA transient transfection reversed the effects of fisetin on cytoprotection, ROS reduction, NO, PGE2, IL-1β, IL-6, and TNF-α production, and NF-κB DNA-binding activity. Moreover, fisetin increased Akt phosphorylation and a PI3K pathway inhibitor (LY294002) abolished fisetin-induced cytoprotection and NO inhibition. Taken together, these results provide evidence for a beneficial role of fisetin in skin therapy. Copyright © 2015. Published by Elsevier B.V.

Hydrogen peroxide modifies both activity and isoforms of acetylcholinesterase in human neuroblastoma SH-SY5Y cells

Directory of Open Access Journals (Sweden)

Alba Garcimartín