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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]

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]

: 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]