Search results for "pero"
showing 10 items of 3365 documents
In-situ synthesis of hydrogen peroxide in tandem with selective oxidation reactions: A mini-review
2014
7 Figuras, 6 Tablas
2015
One-pot combination of the in-situ generation of hydrogen peroxide (H2O2) with selective oxidation reactions enhances the environmental and economic attractiveness of the use of H2O2 as green oxidant at industrial scale. This tandem reaction improves not only the safety aspects associated to H2O2 storage and transportation but also reduces the capital and operation costs. This review covers the progress in the field focussing on the areas of catalysis development, mechanistic understanding and engineering approaches (such as membrane reactors) for specific systems involving epoxidation of propylene oxide, hydroxylation of benzene, oxygenate synthesis from methane and Fenton processes, highl…
Association of military training with oxidative stress and overreaching.
2011
ABSTRACT: We hypothesized that increased oxidative stress and disrupted redox balance may be predisposing factors and markers for overreaching (OR). Purpose: The study's purpose was to examine whether oxidative stress markers and antioxidant status and physical fitness are related to OR during an 8-wk military basic training (BT) period. Methods: Oxidative stress and antioxidant status were evaluated in the beginning and after 4 and 7 wk of training in 35 males (age = 19.7 ± 0.3 yr) at rest and immediately after a 45-min submaximal exercise. Physical activity (PA) was monitored by an accelerometer throughout BT. Indicators of OR were also examined. Results: From baseline to week 4, increase…
Synergistic Anticancer Therapy by Ovalbumin Encapsulation-Enabled Tandem Reactive Oxygen Species Generation
2020
Abstract The anticancer efficacy of photodynamic therapy (PDT) is limited due to the hypoxic features of solid tumors. We report synergistic PDT/chemotherapy with integrated tandem Fenton reactions mediated by ovalbumin encapsulation for improved in vivo anticancer therapy via an enhanced reactive oxygen species (ROS) generation mechanism. O2 .− produced by the PDT is converted to H2O2 by superoxide dismutase, followed by the transformation of H2O2 to the highly toxic .OH via Fenton reactions by Fe2+ originating from the dissolution of co‐loaded Fe3O4 nanoparticles. The PDT process further facilitates the endosomal/lysosomal escape of the active agents and enhances their intracellular deliv…
Defective copper transport in the copt5 mutant affects cadmium tolerance.
2014
Cadmium toxicity interferes with essential metal homeostasis, which is a problem for both plant nutrition and the consumption of healthy food by humans. Copper uptake is performed by the members of the Arabidopsis high affinity copper transporter (COPT) family. One of the members, COPT5, is involved in copper recycling from the vacuole toward the cytosolic compartment. We show herein that copt5 mutants are more sensitive to cadmium stress than wild-type plants, as indicated by reduced growth. Exacerbated cadmium toxicity in copt5 mutants is due specifically to altered copper traffic through the COPT5 transporter. Three different processes which have been shown to affect cadmium tolerance ar…
Globins and hypoxia adaptation in the goldfish, Carassius auratus
2008
Goldfish (Carassius auratus) may survive in aquatic environments with low oxygen partial pressures. We investigated the contribution of respiratory proteins to hypoxia tolerance in C. auratus. We determined the complete coding sequence of hemoglobin α and β and myoglobin, as well as partial cDNAs from neuroglobin and cytoglobin. Like the common carp (Cyprinus carpio), C. auratus possesses two paralogous myoglobin genes that duplicated within the cyprinid lineage. Myoglobin is also expressed in nonmuscle tissues. By means of quantitative real-time RT-PCR, we determined the changes in mRNA levels of hemoglobin, myoglobin, neuroglobin and cytoglobin in goldfish exposed to prolonged hypoxia (48…
Difference in the behavior of methyl (S)-?-bromopropionate in its addition to trimethylvinylsilane depending on the method of initiation
1996
The addition of methyl (S)-2-bromopropionate to trimethylvinylsilane initiated by systems based on iron pentacarbonyl affords a racemic adduct and is accompanied by racemization of the unreacted chiral ester. In the presence of benzoyl peroxide, the reaction proceeds similarly, but no racemization of the starting chiral ester occurs.
Hydrothermally Synthesized Strontium Peroxyapatite
2015
The current research focuses on peroxide ion incorporation in the structure of strontium hydroxyapatite (SrHAp) by exposure to H2O2 ina closed hydrothermal vessel under mild conditions at 130 to 170 °C. Peroxide enriched strontium apatite (SrPerAp) was characterized for structure by X-Ray diffraction, for peroxide content- by permanganometric titration and then viewed by SEM. This study continued from previous work that used 30%H2O2 and showed a higher included peroxide content after processing with 50% H2O2 at 130 °C 70% of the theoretical peroxide content in apatitic channels of strontium apatite. This is the highest peroxide content incorporated to date and employs a lower temperature th…
Effective Recovery Process of Copper from Waste Printed Circuit Boards Utilizing Recycling of Leachate
2020
AbstractThis study presents an optimized leaching and electrowinning process for the recovery of copper from waste printed circuit boards including studies of chemical consumption and recirculation of leachate. Optimization of leaching was performed using response surface methodology in diluted sulfuric acid and hydrogen peroxide media. Optimum leaching conditions for copper were found by using 3.6 mol L−1 sulfuric acid, 6 vol.% hydrogen peroxide, pulp density of 75 g L−1 with 186 min leaching time at 20°C resulting in complete leaching of copper followed by over 92% recovery and purity of 99.9% in the electrowinning. Study of chemical consumption showed total decomposition of hydrogen pero…
Interrelazioni tra disfunzione endoteliale e stress ossidativo; valutazione della perossidazione lipidica in particolari quadri clinici
2015
Il termine "disfunzione endoteliale" identifica una condizione patologica caratterizzata da ridotta vasodilatazione e da attività procoagulante e pro-infiammatoria, correlata ad una ridotta biodisponibilità di ossido nitrico (NO), ad un eccesso ossidativo e ad un'aumentata azione dell'endotelian 1 (ET-1).