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[en] Multi-layer films consisting of oxalate, hydrogen peroxide and various fluorescers are mechanically activated to emit the visible and near-infrared chemiluminescent light. By optimization of composition and thickness of each layer, chemiluminescence can be long lasting, typically over 30 min. The simple pattern displays have also been demonstrated. - Highlights: • Peroxyoxalate chemiluminescence (CL) from a solid multi-layer film has been achieved. • Visible and near infrared CL occurs through mechanical activation. • The CL light can be long lasting, typically over 30 min. • Simple CL display has been demonstrated by the method of array and print pattern.
[en] This invention concerns a process for extracting uranium as peroxide from an aqueous solution of uranyl containing dissolved vanadium and sodium, as impurities. The process consists in treating the uranyl solution with hydrogen peroxide in a quantity of not less than 0.5 parts of H2O2 per part of dissolved vanadium (V2O5), in excess of the amount stoichiometrically necessary (0.126 part per part of U3O3) to give uranium peroxide. The hydrogen peroxide treatment is performed in three successive stages: precipitation, digestion and post digestion. The aqueous solutions of uranyl employed for operating the invention may be eluates resulting from ion exchange or solvent extraction, or an acid solution of sodium diuranate
[fr]La presente invention a pour objet un procede d'extraction de l'uranium sous forme de peroxyde a partir d'une solution aqueuse d'uranyle contenant du vanadium et du sodium a l'etat dissous, a titre d'impuretes. Le procede consiste a traiter la solution d'uranyle a l'aide de peroxyde d'hydrogene en quantite egale a au moins 0,5 partie de H2O2 par partie de vanadium (V2O5) dissous, en exces de la quantite stoechiometriquement necessaire (0,126 partie par partie d'U3O3) pour former le peroxyde d'uranium. Le traitement par le peroxyde d'hydrogene est effectue en trois phases successives, a savoir, une phase de precipitation, une phase de digestion, et une phase de post-digestion. Les solutions aqueuses d'uranyle, utilisees pour la mise en oeuvre de l'invention, peuvent etre des eluats resultant d'un echange d'ions ou d'une extraction par solvant, ou une solution acide de diurana
[en] It has been studied the regularities of the change of pH indicator, chemical oxygen demand (COD) and the formation of hydrogen peroxide and carbon dioxide, as well as UV absorption spectra during the radiolysis of two-phase system of transformer oil, containing 5-40 ppm polychlorobiphenyls with water under the influence of γ-radiation. It has been established that, the increase in the initial concentration of PCB leads to an increase in the radiation-chemical yield of hydrogen peroxide up to 4.7 molecule/100 eV. The increase of the PCB concentration in the oil leads to an increase in the yield of CO2 from 0.18 to 0.24 molecule/100 eV in the range of PCB concentration 5-40 ppm in the oil. It has been shown that, the values of Abc increase from 3 up to∼10 with the increase of absorption dose during the radiolysis of a system, containing 5 ppm PCB. A further increase in the dose leads to a decrease in Abs up to∼3.6 at 68.4 kGy.
[en] Both transient photolysis and steady-state photo-degradation experiments were performed to gain insight into the kinetics and mechanisms of degradation of p-nitroaniline (p-NA) in aqueous solutions. Monophotonic photo-ionization of p-NA was characterized by 266 nm Laser Flash Photolysis (LFP). The quantum yield of eaq- was calculated. Radical cations and neutral radicals of p-NA were identified, respectively. The LFP of p-NA with H2O2 in aqueous solutions was investigated for the first time. For steady-state photo-degradation, degradation of p-NA was observed at diverse irradiation conditions under 254 nm UV light. Direct photo-degradation of p-NA by 254 nm UV light in aqueous solution was very difficult. Once H2O2 was added into the experimental system, degradation of p-NA was enhanced remarkably. In the absence of O2, degradation rate increased rapidly along with the irradiation time and reached 80% at 10 min. p-NA could be totally removed after 15 min in UV/H2O2 process. In the presence of O2 and H2O2, degradation rate increased linearly along with the irradiation time and reached 80% at 7.5 min. p-NA could be totally removed after 10 min. The mechanisms behind the photo-degradation of p-NA were discussed.
[en] The work scope of 'Biological Research for the Radiation Protection' had contained the research about ornithine decarboxylase and its controlling proteins, thioredoxin, peroxiredoxin, S-adenosymethionine decarboxylase, and glutamate decarboxylase 67KD effect on the cell death triggered ionizing radiation and H2O2(toxic agents). In this study, to elucidate the role of these proteins in the ionizing radiation (or H2O2)-induced apoptotic cell death, we utilized sensesed (or antisensed) cells, which overexpress (or down-regulate) RNAs associated with these proteins biosynthesis, and investigated the effects of these genes on the cytotoxicity caused by ionizing radiation and H2O2(or paraquat). We also investigated whether genisteine(or thiamine) may enhance the cytotoxic efficacy of tumor cells caused by ionizing radiation (may enhance the preventing effect radiation or paraquat-induced damage) because such compounds are able to potentiate the cell-killing or cell protecting effects. Based on the above result, we suggest that the express regulation of theses genes have potentially importance for sensitizing the efficiency of radiation therapy of cancer or for protecting the radiation-induced damage of normal cells
[en] Highlights: • The function of 2-Cys Prxs in rice associated with potassium deficiency tolerance is presented. • OsPRX2 contributes to stomatal closure and improves potassium deficiency tolerance is proposed. • OsPRX2 may be a good candidate to improve K+ efficient tolerance in rice. Peroxiredoxins (Prxs) which are thiol-based peroxidases have been implicated in the toxic reduction and intracellular concentration regulation of hydrogen peroxide. In Arabidopsis thaliana At2-CysPrxB (At5g06290) has been demonstrated to be essential in maintaining the water-water cycle for proper H2O2 scavenging. Although the mechanisms of 2-Cys Prxs have been extensively studied in Arabidopsis thaliana, the function of 2-Cys Prxs in rice is unclear. In this study, a rice homologue gene of At2-CysPrxB, OsPRX2 was investigated aiming to characterize the effect of 2-Cys Prxs on the K+-deficiency tolerance in rice. We found that OsPRX2 was localized in the chloroplast. Overexpressed OsPRX2 causes the stomatal closing and K+-deficiency tolerance increasing, while knockout of OsPRX2 lead to serious defects in leaves phenotype and the stomatal opening under the K+-deficiency tolerance. Detection of K+ accumulation, antioxidant activity of transgenic plants under the starvation of potassium, further confirmed that OsPRX2 is a potential target for engineering plants with improved potassium deficiency tolerance.
[en] Complete text of publication follows. The aim of this study was to prepare nickel oxide nanoparticles obtained from aqueous solutions using radiation energy. While works dealing with radiation preparation of nickel nanoparticles are quite numerous, reports dealing with radiation preparation of nickel oxide are rather scarce. Properties of NiO and other catalysts are affected by the method of preparation. It varies the purity, the size of crystallites, the stoichiometry, the specific surface area, the surplus oxygen, and the amount of active catalytic centres. Particle size uniformity and high chemical purity of prepared materials are advantages of radiation method. Five basic aqueous solutions containing nickel formate and other compounds, including hydrogen peroxide, polyvinyl alcohol (PVA), and isopropyl alcohol (IPA), were used for preparation of nickel oxide. Prepared solutions were irradiated by accelerated electrons with doses in the range 0 200 kGy. During irradiation, the solutions changed their colour due to the formation of solid phase. In few cases, the formation of true colloid was observed. With increasing dose up to 80 kGy, the yield of the solid phase increases. Changes caused by irradiation were determined by UV/VIS spectrophotometry in the range of 190-900 nm. The solid phase from the solutions irradiated with the optimum dose of 80 kGy was separated via ultrafiltration and carefully dried. The composition of the solid phase was determined via X-ray powder diffraction. From diffractograms the size of crystallites was determined. The specific surface area was measured using isothermal adsorption of nitrogen from gas mixture hydrogen - nitrogen. Catalytic activity was studied by catalytic degradation of aqueous solution of hydrogen peroxide. Rate constants were measured at four temperatures. The solid phase was annealed under vacuum at 200 deg C for 2 hours. The characteristics of annealed and unannealed materials were compared using all previously mentioned methods. The solid phase formed was found to be pure non-stoichiometric nickel oxide in all studied solutions; the size of the particles was calculated to be in order of tenth of nm. The catalytic activity of samples was determined to be significantly higher compared to commercial non-stoichiometric NiO (LACHEMA). The obtained results indicate that radiation technique is a viable and very promising method for preparation of highly pure NiO catalysts with uniform small-sized particles.
[en] Highlights: • Long-term stability of CNTs in 30% w/v H2O2 were examined at different temperatures. • Total surface oxygen content correlated to the final H2O2 concentration. • The size of CNTs decreased with H2O2 oxidation time. • Oxidation of CNTs underwent purification and functionalization processes.
[en] A facile strategy for detecting xanthine in serum samples by copper nanocluster (CuNCs) with high intrinsic peroxidase-like activity was reported. Firstly, a simple, mild and time-saving method for preparing CuNCs was developed, in which dithiothreitol (DTT) and bovine serum albumin (BSA) were used as reductant and stabilizer, respectively. The as-prepared CuNCs exhibited a fluorescence emission at 590 nm with a quantum yield (QY) of approximately 5.29%, the fluorescence intensity of the as-prepared CuNCs exhibited no considerable change when stored under ambient condition with the lifetime is 1.75 μs. Moreover, the as-prepared CuNCs exhibited high intrinsic peroxidase-like activity with lower Km (Km = 8.90 × 10−6 mol L−1) for H2O2, which indicated that CuNCs have a higher affinity for H2O2. Compared with natural enzyme, the as-synthesized CuNCs are more catalytic stable over a wide range of pH (4.0~13.0) and temperature (4~80 °C). Finally, an indirect method for sensing xanthine was established because xanthine oxidase can catalyse the oxidation of xanthine to produce H2O2. Xanthine could be detected as low as 3.8 × 10−7 mol L−1 with a linear range from 5.0 × 10−7 to 1.0 × 10−4 mol L−1. These results proved that the proposed method is sensitive and accurate and could be successfully applied to the determination of xanthine in the serum sample with satisfaction.
[en] Tetraacetylethylenediamine (TAED) activated hydrogen peroxide system had been applied for bleaching of crude cellulose extracted from jute fiber. Comparing with conventional hydrogen peroxide bleaching system, those results showed that bleaching temperature and time could be effectively reduced, and a preferable whiteness could be produced under faint alkaline condition. And the optimum conditions for activated bleaching system could be summarized as molar ratio of H2O2/TAED 1:0.7, pH 8, pure hydrogen peroxide 0.09 mol/L, temperature 70 °C and time 60min. (paper)