Influence Of Peroxide Research Articles

The influence of hydrogen peroxide on the rheological behaviour of Ultrez-21 gels

The influence of hydrogen peroxide on the rheological behaviour of Ultrez-21 gels

Enhanced Peroxidase Mimetic Activity of Magnetic Porous Carbon (MPC) Utilized in Colorimetric Sensing of Hg (II) Ions in Aqueous Medium

AbstractA new sensitive colorimetric sensor was designed to investigate the presence of Hg2+ in aqueous solution by using Fe3O4 NP impregnated on carbon nanocomposite(MPC) synthesized from MIL88 A which possess an excellent peroxidase mimicking activity that brings oxidation of 3, 3’, 5, 5’‐ tetramethylbenzidine (TMB) under the influence of hydrogen peroxide (H2O2) to produce blue colour in the solution. The solution was decolorized by the addition of Glutathione (GSH) which restores the TMB radical cations and ceased the oxidation reaction. Addition ofHg2+ ions to the solution bring back a strong blue colour due to the strong affinity of Hg 2+ with the thiol groups of GSH which promote the oxidation of TMB in the solution. Based on these strategies, we have developed a sensitive andselective colorimetric sensor for the determination of Hg (II) in aqueous solution with the detection limit value of 236 pM and a linear relationship of R2=0.994. The proposed mechanism was successfully implemented for the detection of mercury in real water samples for environmental applications.

Synthesis and Antibacterial Activity of (AgCl, Ag)NPs/Diatomite Hybrid Composite.

In the present research, hybrid (AgCl, Ag)NPs/diatomite composites were synthesized by direct impregnation with aqueous silver nitrate solutions. The silver chloride nanoparticles (AgCl-NPs) were formed as an effect of the exchange reaction when silver interacted with the diatomite mineral impurity halite. Nanoparticles of metallic silver (AgNPs) were created by the reduction of silver ions under the influence of hydrogen peroxide. The content of silver chloride nanoparticles in the (AgCl, Ag)NPs/diatomite composite was limited by the content of the halite in the used diatomite. Samples of natural diatomite and synthesized (AgCl, Ag)NPs/diatomite composites were examined by using scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, infrared spectroscopy and thermogravimetric analysis. Moreover, the antibacterial potential of synthesized composites was also studied using the MIC (minimal inhibitory concentration) method against the most common drug-resistant microorganisms in the medical field: Gram-positive Staphylococcus aureus and Gram-negative Klebsiella pneumoniae. The obtained hybrid (AgCl, AgNPs)/diatomite composites were shown to have antimicrobial potential. However, widespread use requires further study by using various microorganisms and additional cytotoxic studies on eukaryotic systems, e.g., cell lines and animal models.

Oxidative degradation of Acid Blue 111 by electro-assisted Fenton process

The degradation of Acid Blue 111 anthraquinone dye has been studied by the simple electro-assisted Fenton process and the obtained results were compared to the Fenton process. Ferrous sulphate and hydrogen peroxide were used and in the electro-assisted Fenton process IrOx electrode was used as the anode. The influence of hydrogen peroxide and ferrous ion concentration, as well as pH on the processes was investigated. A second-order kinetic was established and rate constants were determined. The degradation was followed by ultraviolet-visible spectroscopy, gas and liquid chromatography-mass spectrometry analysis. Mineralization of Acid Blue 111 was confirmed by total organic carbon analysis and ion chromatography analysis. Efficiency and energy consumption of the processes were calculated. Also, phytotoxicity was studied using the Mung bean seeds. According to the obtained results, the simple electro-assisted Fenton process was much efficient in the degradation of Acid Blue 111 dye than the Fenton process.

The Influence of Peroxide on the Temperature Dependence of the Electric Conductivity of a Carbonaceous Polymer Composite

We have observed significant differences between the temperature dependences of electric resistivity of a carbonaceous polymer composite based on ethylene vinyl acetate and the same composite saturated with peroxide. It is established that there is a quite clear correlation between characteristic points on the temperature dependences of resistivity and the curves of differential scanning calorimetry.

Photo-assisted activation of H2O2 over Nb2O5 – The role of active oxygen species on niobia surface in photocatalytic discoloration of Rhodamine B

The influence of hydrogen peroxide on the efficiency of Rhodamine B (RhB) photooxidation over Nb2O5, which exhibits unique ability to generate strongly oxidative species both upon irradiation with UV light and upon treatment with hydrogen peroxide, was investigated. According to the results, niobia displays low activity in RhB discoloration by photocatalytic and Fenton-like processes, but the efficiency of the reaction is greatly improved when both advanced oxidation processes are combined. The tests with the use of various reactive oxygen species scavengers revealed that the crucial species responsible for the improved efficiency of RhB discoloration in the hybrid process were superoxide radical anions (O2•−) and singlet oxygen (1O2). It was documented that the former species exhibited low activity in RhB discoloration, but they were the precursors of the latter species, which played the key role in the dye discoloration.

Hydrogen peroxide vapour treatment inactivates norovirus but has limited effect on post-treatment viral RNA levels

Background: Hydrogen peroxide vapour is used as a room disinfectant. Its activity against murine norovirus, a surrogate viability marker for human norovirus, indicates that it is also active against human norovirus.Aim: The aim of this study is to assess how this effect on viability is reflected in measurements of RNA by quantitative PCR (qPCR).Methods: Faeces suspensions of two human norovirus field strains, genogroup I and II and one cultured murine norovirus strain, (genogroup V) were dried on plastic plates, and underwent hydrogen peroxide vapour treatment or were mock treated. The influence of hydrogen peroxide on RNA was measured on genogroups I, II and V by qPCRs and for the cultivable murine norovirus also for viability by cell culture. Virucidal activity on murine norovirus was measured by endpoint titrations as the 50% tissue culture infectious dose, based both on cytopathic effect and on presence of replicating intracellular minus strand RNA.Results: The mean impact on the human norovirus qPCRs was 0.4 log10. The murine norovirus qPCR changed by 1.7 log10 but by an alternative qPCR only by 0.4 log10. These minor changes contrasted the 4.5-5.0 log10 murine norovirus viability reduction after treatment measured by cytopathic effect or intracellular negative-strand RNA.Conclusion: Inactivation of murine norovirus viability by hydrogen peroxide vapour was not reflected in qPCR levels. This finding might be extrapolated to the related human norovirus genogroups. We further found that cellular minus strand murine norovirus PCR was an observer-independent marker to study reduction of murine norovirus viability.

Degradation of thiophanate-methyl fungicide by photo-Fenton process using lab-scale annular and solar tubular reactors

In this work, thiophanate-methyl fungicide was degraded by the homogeneous photo-Fenton process using lab-scale annular and solar tubular reactors. A UV light was used as artificial irradiation source in the lab-scale reactor. The influence of hydrogen peroxide (H2O2) dosage and initial pollutant concentration on the process efficiency was investigated. Degradation efficiency of thiophanate-methyl fungicide was monitored by measuring the total organic carbon (TOC). The results revealed that the variable H2O2 dosage showed remarkable effect on the process efficiency, whereas the fungicide concentration showed little influence. Both reactors showed similar efficiencies, reaching a fungicide mineralisation of 80% at 120 min of reaction time. Therefore, both reactors demonstrate to be effective on the thiophanate-methyl degradation from aqueous solution.

Influence of Hydrogen Peroxide on the Photoanodization of n-Si in the Breakdown Mode

The electrochemical etching of n-Si (100) in an electrolyte composed of 4% HF solution in 30% hydrogen peroxide is experimentally studied at a voltage exceeding the breakdown voltage. The effect of the illuminance of the wafer back side on the porous-structure morphology and such parameters as porosity, effective valence, and pore growth rate are examined. The data obtained are compared with those for structures subjected to photoanodization in an aqueous electrolyte at the same HF concentration. It is found that the presence of hydrogen peroxide strongly changes the morphology of macropores, makes their diameter smaller, and raises by a factor of ~2 the rate of growth deeper into the substrate. In the presence of H2O2, there appear inclined secondary pores oriented at an angle of 15°–35° to the main channel axis and a number of breakthrough mesopores propagating in the 〈100〉 directions in the plane parallel to the sample surface. The effective valence of the electrochemical dissolution of silicon in the HF:H2O2 electrolyte at a low illumination level is close to unity and grows with increasing light intensity, always being smaller than 2.

Influence of hydrogen peroxide in enhancing photocatalytic activity of carbon nitride under visible light: An insight into reaction intermediates

Carbon nitride is a known photocatalyst that can be activated under visible light irradiation. In this research, the combined effect of carbon nitride and hydrogen peroxide in photocatalytic degradation of methylene blue (MB) in water was investigated under visible light. Carbon nitride was synthesized by thermal polymerization of dicyandiamide and characterized by x-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), Energy dispersive x-ray (EDX), Fourier transform infrared spectroscopy (FTIR) and pore textural properties. The kinetic study of degradation of MB with carbon nitride and in presence of hydrogen peroxide showed complete degradation of MB before 45 min of time interval. The kinetic studies were also performed by varying the dose of photocatalyst and initial concentration of MB and it was shown that higher dose of photocatalyst and lower concentration of MB resulted in higher rate of degradation. The dual role of hydrogen peroxide can be related to the generation of additional highly reactive hydroxyl radicals in presence of photocatalyst and prevention of recombination of holes and electrons of carbon nitride thereby improving its photocatalytic activity. The pH study revealed that neutral pH of the solution results in the highest rate of degradation. Analysis of liquid chromatography–mass spectroscopy (LCMS) results helped to reveal the reaction steps of photocatalysis of MB and it was found that the four stages of photodegradation of MB were demethylation, ring shortening, ring opening and complete mineralization.

CARDIOPROTECTIVE EFFECT OF TUMOR NECROSIS FACTOR ALPHA ANTAGONIST IN DOXORUBICIN MYOCARD TOXICITY

Doxorubicin (Dox) is a first line drug in neoplasia treatment. It is however cardiotoxic even in moderate dosages. High mortality of oncological patients from cardiomyopathic heart failure on Dox treament is a serious problem of oncology and cardiology. Among the cardiotoxicity factors of Dox are activation of inflammatory reaction and ability of the drug to increase expression of tumor necrosis factor alpha (TNF-a) in myocardium and coronary arteries. Aim. To study in laboratory conditions the opportunities for cardioprotection from Dox with TNF-a antagonist. Material and methods. Doxorubicin myocardial damage (DMD) was simulated on the white rats by intraabdominal load of Dox in cumulative dosage 16 mg/kg within 2 weeks. In other series, to the animals together with Dox every day during 2 weeks intraabdominally the TNF-a antagonist was loaded — monoclonal antibody (ma-TNF-a) dosage 5,0 mg/kg. Cardioprotective effect ma-TNF-a was evaluated on the perfusion model of the isolated heart with assessment of: (1) inotropic response of myocardium on stimulation by noradrenalin and endothelin-1 (ET-1); (2) coronary functional reserve on acetylcholine, adenosine, bradikinine and hydrogen peroxide influence; (3) dynamics of end diastolic pressure (EDP) of the left ventricle in the ischemia-reperfusion syndrome. Results. In DMD, there was significant disorder of the diastole, systole and pumping function of the heart even in physiological values of filling and resistance. Action ma-TNF-a was followed by a significant increase of cardiac output, maximum velocity of isovolumetric contraction and relaxation by 14,2-26,3%, and significant decrease of EDP by 30,1%. With action of ET-1 on the heart with DMD there was negative inotropic effect, mediated by the decrease of systolic pressure (SP) in LV by 9,1% comparing to the baseline, and when ma-TNF-a made analogically to control positive inotropic effect (SP in LV increased by 8,5%) and increase of cardiac output by 14,3%. Cardioprotective effect of ma-TNFa followed by significant increase of coronary functional reserve. It is notable that coronary reactivity, common for the action hydrogen peroxide and mediated by hyperpolarization, did not change in DMD. Usage of ma-TNF-a improved resistance of the heart to ischemia and reperfusion, as the measured EDP values measured at various time frames were significantly lower than EDP, and the level of SP in LV — significantly higher. Conclusion. Usage of TNF-a antagonist in DMD made cardioprotective effect: significant increase of cardiac output, SP, maximum velocity of isovolumetric contraction and relaxation, significant decrease of EDP, appearance of postitive inotropic response of the heart on ET-1, and improvement of endothelium-dependent coronary dilation. Action of ma-TNF-a was followed by decrease of ischemic cardiac contracture and significantly better recovery of SP and EDP during reperfusion.

Hydrogen peroxide/UV treatment on polylactide/polyurethane blends for biomedical applications

Biodegradable polymers should be non-toxic, possess low immunogenicity and good mechanical properties. Due to their hydrophobicity and their low surface energy cells only poorly attach, spread and proliferate on these biodegradable polyesters. Therefore, the surface of these polyesters should usually be modified and already several approaches have been presented to increase their cell affinity. In this research the influence of hydrogen peroxide combined with ultra violet irradiation on wettability, morphology and mechanical properties of PU/PLA blends as well as their pure components. It was clearly visible that both pure PU and PLA acted completely different form PU/PLA blend during treatment. The wettability of pure polymers changed after H2O2/UV, PU surface became more hydrophilic, whereas PLA becomes slightly hydrophobic. Due to micropores and microcracks visible on surfaces resulted from breaking ester linkage, deterioration of their mechanical properties was also observed. The exposure of PU/PLA films to H2O2/UV irradiation showed the change of wettability toward more hydrophilic and increase of mechanical properties because of specific affinity to the etching process.

Hydrogen peroxide stimulates exocytosis of von Willebrand factor in human umbilical vein endothelial cells

The aim of our research was to study the influence of hydrogen peroxide on the exocytosis of von Willebrand factor (vWF) in human umbilical vein endothelial cells (HUVEC). We have found that H2O2 at a non-toxic concentration (100 μM) increases the amount of vWF secreted by HUVEC by 43 ± 14% over control (p < 0.03) and elevates total exposition of vWF on cell surface by 89 ± 5% (p < 0.01). Analysis of immunofluorescent images of HUVEC with CellProfiler program revealed that the average number of antigen positive structures on the single cell surface increases from 11.4 ± 0.16 in control up to 17.5 ± 0.21 after incubation with H2O2 (p < 0.01). vWF is exposed on the cell surface as dots with the average sizes around 1–3 μm. H2O2 causes an increase in the number of these dots and the appearence of the strings of vWF which are absent in control HUVEC. It is suggested that H2O2 may serve as a messenger which stimulates vWF exocytosis.

Cisplatin-induced human peripheral blood mononuclear cells' oxidative stress and nephrotoxicity in head and neck cancer patients: the influence of hydrogen peroxide.

Cisplatin is a widely used antineoplastic agent in the treatment of head and neck cancer. However, it is highly nephrotoxic. Oxidative stress is the main mechanism responsible for cisplatin-induced nephrotoxicity. The aim of this study was to characterize cisplatin-induced nephrotoxicity, oxidative stress in peripheral blood mononuclear cells, and the relationship between them. Twenty-four patients were included in the study. Patients had their blood collected prior to cisplatin administration, and 5 and 20days after initiating therapy, to assess renal function and to determine oxidative stress with MitoSOX™Red, H2DCF-DA, and Amplex® Red tests. Renal function was assessed by measuring serum creatinine, creatinine clearance, and blood urea nitrogen (BUN). Serum creatinine and creatinine clearance were used to grade nephrotoxicity using Common Terminology Criteria for Adverse Events (CTCAE) v4.0. Compared to baseline values, the mean BUN and serum creatinine increased 135 and 100%, respectively, 5days after cisplatin infusion. Mean creatinine clearance showed a 43% decrease compared to baseline value. Non-statistically significant changes in superoxide anion (O 2•- ), hydrogen peroxide (H2O2), and general reactive oxygen species production occurred. A higher production of H2O2 was correlated with variation in serum creatinine, and was associated with higher grades for serum creatinine increases and creatinine clearance reductions. Linear regression analyses showed an association between H2O2 production and serum creatinine, creatinine clearance, and BUN levels. These results were observed for 5days following cisplatin administration. In conclusion, H2O2 production was significantly related to changes in all renal parameters that were evaluated, following the cisplatin infusion.

Peroxy-Titanium Complex-based inks for low temperature compliant anatase thin films

Stable highly crystalline titanium dioxide colloids are of paramount importance for the establishment of a solution-processable library of materials that could help in bringing the advantages of digital printing to the world of photocatalysis and solar energy conversion. Nano-sized titanium dioxide in the anatase phase was synthesized by means of hydrothermal methods and treated with hydrogen peroxide to form Peroxy-Titanium Complexes (PTCs). The influence of hydrogen peroxide on the structural, optical and rheological properties of titanium dioxide and its colloidal solutions were assessed and a practical demonstration of a low temperature compliant digitally printed anatase thin film given.

Photodegradation of the antibiotic spiramycin studied by high-performance liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry

ABSTRACTThe degradation of spiramycin induced by ultraviolet (UV) irradiation was studied at pH 3–4, 6–7 and 8–9 using high-performance liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry. Furthermore, the influence of hydrogen peroxide and oxygen on the photodegradation was investigated. Three degradation products were observed in the presence of oxygen and four in the absence of oxygen. The degradation kinetics were monitored as mass area-time curves, analyzed and described using subsequent follow-up reaction first-order models. The m/z values of the degradation products were determined to be 160, 322 and 366, the latter representing two separate products, the sugar moieties of spiramycin. Remainders of the macrocycle or the intact lactone ring of spiramycin were not observed, since the conjugated π-electron system was assumed photoexcited and thus undergoing photodegradation and fast destruction of the ring. The kinetic of the degradation of spiramycin itself was described using a first-order model. The degradation was accelerated upon addition of hydrogen peroxide. In contrast, systematic acceleration depending on pH could not be found. The absence of oxygen did not lead to any significant acceleration. The findings are interpreted in terms of the effectiveness of advanced oxidation processes and their potential use as a fourth purification step in wastewater treatment plants.

Ozone and Hydrogen Peroxide Influence on Intensification of Biological and Physical and Chemical Components of the Iron and Manganese Removal from Water

Background. Compounds of iron and manganese are the most common components that are present in groundwater of nearly all regions of Ukraine. Elevated concentrations of iron and manganese cause deterioration of the organoleptic properties of water, leading to the formation of precipitates, overgrown water supply and water intake valves. Therefore, there is a need to improve existing technologies to extract these elements from the water.Objective. The aim is to determine the effects of oxidants – ozone and hydrogen peroxide – at doses that are not sufficient for disinfection (0.25–3.0 mg/dm3), compared with the oxygen for iron and manganese removal from water through filtration on the zeolite filters.Methods. The research was conducted on iron-bearing groundwater. Water is treated with oxygen at the laboratory unit, which consists of aerator closed contact capacity and free-flow filter with zeolite loading. Water ozonation at manganese removal on zeolite filter was conducted in Drexel glasses, which acted ozone-air mix with ozone generator. In experiments with hydrogen peroxide in a container of water was added a solution of said reagent in various concentrations, then the mixture was mixed and lodged in the filter.Results. It is shown that at concentrations of oxidants 0.25 and 0.5 mg/dm3 biological processes are dominated. From a technological point of view, it is possible to achieve the same depth cleaning at both low and higher doses of ozone. The implementation process in such circumstances would achieve significant savings of ozone and therefore electricity needed for its formation.Conclusions. The conclusions about the fundamental possibility of intensifying the process of removing compounds of iron and manganese from water through water treatment by ozone in small doses, followed by filtration through a layer of zeolite loadings are carried out. In this regard ozone promotes more efficient removal of water manganese, which is usually quite difficult technological challenge.

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

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.

Influence of Hydrogen Peroxide, Lactic Acid, and Surfactants from Vaginal Lactobacilli on the Antibiotic Sensitivity of Opportunistic Bacteria.

We studied as hydrogen peroxide, lactic acid, or surfactants from clinical isolates of vaginal lactobacilli and cell-free supernatants from probiotic strain LCR35 can influence on the sensitivity of opportunistic bacteria to antibiotics. We found that the most effective in increasing sensitivity to antibiotics were hydrogen peroxide and surfactants or their combination but no lactic acid. In some cases, the effect of the composition of hydrogen peroxide and surfactants was clearly higher than the sum of effects of these substances alone. With using of the supernatant of LCR35 was shown that the combination of surfactant and lactate has greater effect compared with surfactants alone. In concluding, metabolites of vaginal lactobacilli are suitable for the role of "antibiotic assistants" and it can help solve the problems the antibiotic resistance.

Constructing MnO2/single crystalline ZnO nanorod hybrids with enhanced photocatalytic and antibacterial activity

In order to improve the photocatalytic and antibacterial activity of ZnO nanorods, ZnO nanorods decorated with MnO2 nanoparticles (MnO2/ZnO nanorod hybrids) were prepared by using microwave assisted coprecipitation method under the influence of hydrogen peroxide, and the structure, photocatalytic activity and antibacterial property of the products were studied. Experimental results indicated that MnO2 nanoparticles are decorated on the surface of single crystalline ZnO nanorods. Moreover, the resultant MnO2/ZnO nanorod hybrids have been proven to possess good photocatalytic and antibacterial activity, which their degradated efficiency for Rhodamin B (RhB) is twice as the pure ZnO nanorods. Enhancement for photocatalytic and antibacterial activity is mainly attributed to the low band gap energy and excellent electrochemical properties of MnO2 nanoparticles.