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Reactive oxygen species are known to have a harmful activity in living systems. It attracts the attention of researchers due to their capability of damaging crucial biomolecules such as nucleic acids, lipids, proteins, polyunsaturated fatty acids, and carbohydrates and which results many human ailments: atherosclerosis, cancer, diabetes, inflammation, cardiovascular diseases, and neurological disorders. Hence, the investigation of the already known compounds exhibiting antioxidant properties is still an important scientific challenge. So reaction with Co(II)-bound superoxo complex, [(NH3)5Co(O2)Co(NH3)5]5+ (MBSC) and Popofol (PPF), Ferulic Acid (FA) is chosen to study the antioxidant activity of PPF and FA. Redox properties of Popofol (PPF) and Ferulic Acid (FA) which are two phenolic antioxidants are studied through the reduction of Co(II)-bound superoxo complex, [(NH3)5Co(O2)Co(NH3)5]5+ (MBSC) in aqueous acidic media ([H+] = 0.02–0.70 M) under pseudo-first-order condition. For both the PPF and FA, the observed rate increase with the increase in [PPF] and [FA] and the decrease with media [H+] and ionic strength, I. The kinetic analysis reveals that the deprotonated conjugate bases from PPF and FA reduces MBSC with the diffusion-controlled rate of ~ 108 and ~ 1011 M−1 s−1. Since, the decrease in ko values with increase in V/V D2O were not significant, we can propose for a simple electron-transfer (ET) mechanism, rather than proton-coupled electron transfer (PCET) or hydrogen-atom transfer (HAT) mechanism for the reduction in bound superoxide by PPF and FA. The antioxidant property of propofol and ferulic acid has been evaluated by various methods but in our study, the novelty lies on the exploration of the real insight of their antioxidant property by studying the chemical mechanism of their redox properties with MBSC. [ABSTRACT FROM AUTHOR]

BACKGROUND: Biochar has received much attention for disposal of aqueous organic contaminants because of its great potential in adsorption and catalysis. N‐doped rice husk biochar (N‐BC) was synthesized in this work and used to activate potassium peroxymonosulfate (PMS) to remove different types of dyes. The influence of preparation conditions of N‐BC and reactive conditions on removal rate was discussed in detail. Free radical quenching experiment and electron spin resonance were used to analyze the active species and mechanism in the reaction. RESULTS: N‐BC with abundant graphitic‐N, which is the main form of N to activate PMS, can be obtained by N‐doping with carbamide at 900 °C. The removal rate for new coccine can reach nearly 100% in 30 min. Furthermore, the removal rate can still be maintained at 77.21% after reusing four times only washing with water, and it can be further promoted to 98.78% after annealing treatment at 900 °C. N‐BC has excellent applicability to different types of dyes. CONCLUSION: Consequently, the mechanism is the combination of radical (O2•−) and nonradical (1O2) oxidation. First, the preparation method in this work is relatively simple. Second, the material can adapt to a very wide pH range. Third, the material shows high efficiency at room temperature (the removal rate can reach nearly 100% in 30 min). Fourth, the material shows high efficiency with only a small amount. This study provides a new path of rapid dye water purification using biochar, with simple synthesis, wide pH range adaptability, and high efficiency with only a small amount. © 2023 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Trolox-C (TXC) is a water-soluble analogue of α-tocopherol that reduces the metal-bound superoxo complex (SOC), [(NH3)5Co(µ-O2)Co(NH3)5]5+ in water–ethanol media. In aqueous-acid media ([H+] = 0.02–0.70 mol/L), TXC quantitatively reduces SOC under the pseudo first-order reaction condition where the concentration of TXC, [TXC], was at least 10 times or more than that of [SOC]. Variations in media ionic strength suggest for the reaction between two cationic species, and a positive kinetic isotope effect (kH/kD < 1) indicates for a pre-equilibrium step of protonation of the pyran-oxygen of TXC. Both TXC and the protonated TXC, i.e., TXCH, are the potential reductants under the experimental range of media acidity. The reduction of SOC takes place through the single-electron transfer and the kinetic analysis yields the value for second-order rate constants for TXC and TXCH as 9.7 and 3.6 × 103 (mol/L)−1s−1 at 15 °C. [ABSTRACT FROM AUTHOR]

High salinity and drought stresses often cause plants to produce ROS, including hydrogen peroxide (H 2 O 2) and superoxide (O 2 −), which interfere with plant growth and affect crop yield. The transcription factors of the MYB family are involved in responses to biotic and abiotic stresses. Here, we isolated the R2R3-MYB transcription factor gene SlMYB50 and found that silencing of SlMYB50 increased resistance to PEG 6000, mannitol and salt. In addition, the resistance of transgenic tomatoes increased under high salt and drought stress. After stress treatment, the relative water content, chlorophyll content (critical for carbon fixation) and root vitality of the SlMYB50 -RNAi lines were higher than those of the wild-type (WT). The opposite was true the water loss rate, relative conductivity, and MDA (as a sign of cell wall disruption). Under drought stress conditions, SlMYB50 -silenced lines exhibited less H 2 O 2 and less O 2 − accumulation, as well as higher CAT enzyme activity, than were exhibited by the WT. Notably, after stress treatment, the expression levels of chlorophyll-synthesis-related, flavonoid-synthesis-related, carotenoid-related, antioxidant-enzyme-related and ABA-biosynthesis-related genes were all upregulated in SlMYB50 -silenced lines compared to those of WT. A dual-luciferase reporter system was used to verify that SlMYB50 could bind to the CHS1 promoter. In summary, this study identified essential roles for SlMYB50 in regulating drought and salt tolerance. • Silencing of SlMYB50 increases tomato resistance to high salt and drought stress. • Under stress conditions, silencing of SlMYB50 increased the activity of CAT enzymes. • Silencing of SlMYB50 reduces the accumulation of hydrogen peroxide and superoxide anion. [ABSTRACT FROM AUTHOR]

Using some solutions activated by irradiation with non-thermal atmospheric pressure plasma (NTAPP), we had discovered that a new and distinctive mode of cell death, named spoptosis, exists in cells, the induction of which involves the action of reactive oxygen species (ROS). However, it was unknown what types of ROS and how they trigger the cell death. When cells were treated with a higher dose of Ascorbic acid (AA) generating O 2 − and H 2 O 2 or Antimycin A (AM) generating O 2 −, cell death occurred along with cellular shrinkage, Pdcd4 disappearance, and vesicle formation. Only in cells treated with AA, genomic DNA was digested irregularly and membrane permeability increased aberrantly. On the other hand, cells treated with a higher dose of H 2 O 2 displayed cell death and cellular shrinkage but not the other events, and those treated with a lower dose of H 2 O 2 displayed cell death but not the other events. Strikingly, when cells underwent double treatment with AM and H 2 O 2 , the events, which had not been observed by their single treatment, became compensated. All the events were suppressed with an antioxidant, confirming that they were mediated by ROS. Thus, the mode of cell death induced by AA or combination of AM and H 2 O 2 was consistent with that of cell death by NTAPP-activated solutions. These results suggested that O 2 − and H 2 O 2 collaboratively trigger spoptotic cell death with the associated events, and that AA and combination of AM and H 2 O 2 are functionally alternative in place of NTAPP-activated solutions. [ABSTRACT FROM AUTHOR]

Proton-conducting solid oxide cell (H–SOC) is suitable for operation at lower temperatures. However, its commercialization still faces the problem of insufficient catalytic activity of air electrode. Here a triple ionic-electronic conductor PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ (PBSCF) is synthesized by glycine-nitrate method, and the PBSCF slurry was screen printed onto the surface of half-cell which is fabricated by aqueous co-tape casting to obtain the single cell with the structure of PBSCF ǀ BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ (BZCYYb) ǀ NiO-BZCYYb (active layer) ǀ NiO-BZCYYb (support layer). The peak power density of the single cell with dry air as oxidant and hydrogen as fuel at 750, 700, and 650 °C are 958.75, 872.78, and 709.22 mW cm−2, respectively. When the atmosphere is 20%H 2 O+80%air at air electrode side and hydrogen at fuel electrode side, the single cell operating as a proton-conducting solid oxide electrolysis cell shows high electrolysis current densities of 4299.4, 2744.6, 1711.8, and 974.6 mA cm−2 under 1.3 V at 750, 700, 650, and 600 °C respectively. Additionally, during the constant voltage electrolysis, the cell shows a good stability in 78 h at 650 °C. The results show that PBSCF is potential as air electrode of H–SOCs, especially in solid oxide electrolysis cell mode. [Display omitted] • PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ is a promising air electrode material for H–SOC. • The PBSCF was successfully synthesized by GNP. • The conductivity of PBSCF was tested under air with steam content (0, 20% and 40%). • The electrolysis current density is 1711.8 mA cm−2 under 1.3 V at 650 °C. • The single cell shows good stability under 1.3 V electrolysis at 650 °C. [ABSTRACT FROM AUTHOR]

Reactive oxygen species ( ROS) play a crucial role in the early response to plant biotic and abiotic stresses. In this study, bacterial wilt-resistant and wilt-susceptible eggplants were inoculated with Ralstonia solanacearum and the ROS content was analysed. The result revealed an increased accumulation of hydrogen peroxide (H2O2) and superoxide (O2−) in resistant and susceptible eggplant roots after R. solanacearum inoculation. H2O2 and O2− accumulation increased earlier in the inoculated resistant eggplant root than in the inoculated susceptible eggplant root. Real-time polymerase chain reaction results revealed that respiratory burst oxidase homologue (Rboh) A, RbohB, RbohF and PR1 expression levels increased in inoculated resistant eggplant roots at an early stage (0-60 h postinoculation) and were at higher expression levels than those in susceptible eggplant roots. Ascorbate peroxidase, peroxidase and catalase activities were higher in inoculated resistant eggplant roots than in susceptible eggplant roots at the early stage. Hence, an early ROS burst positively regulates bacterial wilt resistance in eggplant. [ABSTRACT FROM AUTHOR]

2-Methoxyestradiol (2-ME) is an estradiol metabolite with antiangiogenic properties. It can be produced by granulosa cells and it is present in normal follicle at high concentrations. The identification of reactive oxygen species (ROS) role in the molecular pharmacology of 2-ME is an active area of research. The objective of this article was therefore to evaluate the effect of 2-ME on both superoxide anion (O2−) production and superoxide dismutase (SOD) activity in swine granulosa cells collected from follicles greater than 5 mm and treated for 48 h with 1 μM 2-ME. 2-ME inhibited ( P < 0.001) O2− generation in swine granulosa cells, while it stimulated ( P < 0.05) the SOD activity. We previously demonstrated that a stimulation of O2− generation triggers angiogenetic response in granulosa cells. Therefore, we argue that the inhibitory effect of 2-ME on O2− could be responsible for its antiangiogenetic effect. [ABSTRACT FROM AUTHOR]

The surface properties of ZrO2 in He, H2, O2, air and wet air at temperatures ranging from 25 to 600 °C have been investigated by means of ESR method. The Zr3+ centers characterized by ESR can be described as the oxygen coordinatively unsaturated Zr sites, mainly located at the corner sites of ZrO2 microcrystallites, on the surface of ZrO2. More Zr3+ centers were formed on the surface of ZrO2 by treating the sample in He at temperatures above 400 °C. And the formation of the Zr3+ centers may be associated with the removal of surface hydroxyl. Although Zr4+ in ZrO2 cannot be reduced at temperatures of up to 600 °C in H2, some surface hydroxyl can be reduced to form F-centers at temperatures higher than 250 °C. And O2− can be produced from the Zr3+ centers and F-centers at temperatures above 400 °C, and it may be associated with both H2 and the trace amount of O2 in H2. [Copyright &y& Elsevier]

The strong influence of oxygen to the positive secondary ion yield determines the problems of SIMS depth profiling of shallow boron implants in silicon, related to surface oxide and formation of modified layer. High value (4 eV) of electron affinity of BO2 molecule responds for the high yield of BO2− negative secondary ions, its small sensitivity to the variation of emission properties of the sample surface and relatively weak dependence on oxygen concentration. The features of using of named ions for shallow boron profiling was studied with a magnetic sector SIMS instrument in a high mass resolution mode under O2− and NO2− primary ion bombardment. The refuse from oxygen flooding allowed to avoid the initial significant change of sputter rate. The studied approach provides simplification of transient phenomena while still keeping sufficient sensitivity. [Copyright &y& Elsevier]

: ObjectivesWe sought to investigate the effects of adding spironolactone (SP) to angiotensin-converting enzyme (ACE) inhibition on endothelium-dependent vasodilation in rats with chronic heart failure (CHF).: BackgroundAdding SP to ACE inhibitors reduces mortality and morbidity in CHF. Endothelial vasomotor dysfunction contributes to increased peripheral vascular resistance and reduced myocardial perfusion in CHF.: MethodsSeven days after extensive myocardial infarction (CHF) or sham operation, Wistar rats were treated with placebo, the ACE inhibitor trandolapril (TR, 0.3 mg/kg body weight per day), SP (10 mg/kg per day) or a combination of both for 11 weeks.: ResultsMaximal acetylcholine-induced, nitric oxide (NO)-dependent relaxation was significantly attenuated in aortic rings from rats with CHF as compared with sham-operated animals (Rmax 44 ± 3% vs. 63 ± 3%). Spironolactone alone had no influence (46 ± 5%) and TR improved NO-mediated relaxation (55 ± 4%), whereas treatment with both completely restored endothelium-dependent vasorelaxation (64 ± 4%). Aortic superoxide formation was significantly increased in rats with CHF as compared with sham-operated animals, but was normalized by treatment with SP or SP plus TR. In addition, aortic messenger ribonucleic acid expression of the oxidase subunit p22phox in rats with CHF was significantly reduced by SP or TR plus SP. Endothelial NO synthase expression was increased in TR-treated animals. Incubation of isolated porcine coronary arteries with SP dose-dependently attenuated superoxide formation.: ConclusionsSpironolactone added to an ACE inhibitor normalizes NO-mediated relaxation in experimental CHF by beneficially modulating the balance of NO and superoxide anion formation. [Copyright &y& Elsevier]

The single-celled yeast Saccharomyces cerevisiae is one of the most valuable laboratory models that has been used successfully to identify factors and pathways involved in several cellular processes, the counterparts of which are evolutionarily conserved. Furthermore, it is also a powerful tool for analyzing the effects of molecules of nutraceutical interest with the view of leading to human health benefits and improving the quality of aging. In this context, we present some of the methods that have allowed us to assess the beneficial influence of a form of vitamin B3, namely nicotinamide, on mitochondrial functionality during yeast chronological aging. Mitochondrial dysfunctions are considered to be hallmarks of aging, and of several metabolic and neurodegenerative diseases. More specifically, these methods concern the determination of the respiratory parameters in intact cells in order to evaluate the efficiency of mitochondrial respiration in concert with the risk of superoxide anion (O 2 - ) production, which results from inefficient respiration. In addition, we describe fluorescent staining specific for O 2 - detection and mitochondrial membrane potential, as well as a simple clonogenic assay based on the ability of cells to grow on a carbon source that requires a functional mitochondrial metabolism.

• RhCl 3 was supported on CeO 2 by Deposition–Precipitation (DP) and Impregnation (Imp) methods. • The catalysts prepared were tested in propylene and carbon black total oxidation. • In DP: EPR evidenced O 2 − presence and XRD detected Rh 2 O 3. • DP is more active than Imp due to Rh 2 O 3 , O 2 −, as well as to easier reducibility and lower particle size of rhodium species. 4 wt% Rh/CeO 2 catalysts were prepared by two different methods: deposition–precipitation (DP) and impregnation (Imp). X-ray diffraction (XRD), differential scanning calorimetry and thermogravimetry (DSC-TG), temperature-programmed reduction (TPR), and electron paramagnetic resonance (EPR) were used for physicochemical characterization. The solids were tested in propylene and carbon black oxidation reactions. The 4%Rh/CeO 2 (DP) showed better catalytic performance in both reactions compared to the catalyst prepared by the impregnation method. The XRD technique evidenced the formation of Rh 2 O 3 phase in the DP-solid after calcination of this latter at 400 °C for 4 h. EPR evidenced, only in the DP-solid, the presence of O 2 − species in interaction with the CeO 2 surface whereas Rh4+ ions in the form of clusters were identified in both solids. The TPR technique showed that the DP-solid was reduced by hydrogen at lower temperature compared to the impregnated one. The higher catalytic performance of the DP-solid was attributed to the presence of O 2 − species along with the presence of Rh 2 O 3 phase in ceria and to the better reducibility and lower particle size of the rhodium species. [ABSTRACT FROM AUTHOR]