Active nano-CuPt3 electrocatalyst supported on graphene for enhancing reactions at the cathode in all-vanadium redox flow batteries

Graphene-supported monometallic (Pt) and bimetallic (CuPt₃) cubic nanocatalysts have been investigated as new positive electrode materials for improving the VO₂⁺/VO²⁺ redox process occurring in the vanadium redox flow batteries (VRB). High-resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM) have been employed to characterize the electrodes. The presence of the CuPt₃ nanocubes on graphene conferred higher electrocatalytic activity due to the much higher electroactive area compared to that obtained with the Pt nanoparticles. The electrochemical surface area of the nano-(CuPt₃)-decorated graphene electrode was 105% higher compared to non-decorated graphene, being then a promising alternative for improving the VRB.     

Protective effect of olive oil and its phenolic compounds against low density lipoprotein oxidation

The protective effect of phenolic compounds from an olive oil extract, and of olive oils with (extra-virgin) and without (refined) phenolic components, on low density lipoprotein (LDL) oxidation was investigated. When added to isolated LDL, phenolics [0.025–0.3 mg/L caffeic acid equivalents (CAE)] increased the lag time of conjugated diene formation after copper-mediated LDL oxidation in a concentration-dependent manner. Concentrations of phenolics greater than 20 mg/L inhibited formation of thiobarbituric-acid reactive substances after AAPH-initiated LDL oxidation. LDL isolated from plasma after preincubation with phenolics (25–160 mg/L CAE) showed a concentration-dependent increase in the lag time of conjugated diene formation after copper-mediated LDL oxidation. Refined olive oil (0 mg/L CAE) and extra-virgin olive oil (0.1 and 0.3 mg/L CAE) added to isolated LDL caused an increase in the lag time of conjugated diene formation after copper-mediated LDL oxidation that was related to olive oil phenolic content. Multiple regression analysis showed that phenolics were significantly associated with the increase in lag time after adjustment for effects of other antioxidants; α-tocopherol also achieved a statistically significant effect. These results indicate that olive oil phenolic compounds protect LDL against peroxyl radical-dependent and metal-induced oxidation in vitro and could associate with LDL after their incubation with plasma. Both types of olive oil protect LDL from oxidation. Olive oil containing phenolics, however, shows more antioxidant effect on LDL oxidation than refined olive oil.     

Steady-state isotopic transient kinetic analysis of steam reforming of methanol over Cu-based catalysts

Mechanistic aspects of steam reforming of methanol were studied via steady-state isotopic transient kinetic analysis over three copper-based catalysts, namely combustion-synthesized Cu-Ce-O and Cu-Mn-O, and commercial Cu-ZnO-Al₂O₃. The “C-path” and “O-path” for the production of CO₂ via steam reforming of methanol was analysed with the following step changes in the feed: ¹²CH₃OH/H₂O/Ar/He → ¹³CH₃OH/H₂O/He and CH₃OH/H₂¹⁶O/Ar/He → CH₃OH/H₂¹⁶O/H₂¹⁸O/He. The presence of CH₃¹⁸OH in the products after the switch to ¹⁸O-labeled water indicates that a major path of the reaction is the one involving a methyl formate intermediate. This appears to be the main path over the Cu-Mn-O catalyst, while parallel paths via dioxomethylene and methyl formate intermediates appear to be operative over Cu-Ce-O and Cu-ZnO-Al₂O₃ catalysts.     

Decreasing the Linoleic Acid to α-Linolenic Acid Diet Ratio Increases Eicosapentaenoic Acid in Erythrocytes in Adults

The n-6/n-3 fatty acid (FA) ratio has increased in the Western-style diet to ~10–15:1 during the last century, which may have contributed to the rise in cardiovascular disease (CVD). Prior studies have evaluated the effects on CVD risk factors of manipulating the levels of n-6 and n-3 FA using food and supplements or investigated the metabolic fate of linoleic acid (LNA) and α-linolenic acid (ALA) by varying the n-6/n-3 ratios. However, no previous studies have investigated the potential interaction between diet ratios and supplementation with eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3). We used a factorial design approach with adults (n = 24) in a controlled feeding trial to compare the accretion of EPA and DHA into red blood cell membranes (RBC) by adding a direct source (algal oil supplement) of EPA and DHA in a diet with a 10:1 versus 2:1 ratio of n-6/n-3 FA. Subjects were randomized into 8-week crossover diet sequences and each subject consumed three of four diets [10:1, 10:1 plus supplement (10:1 + S), 2:1 and 2:1 + S]. LNA and ALA intakes were 9.4 and 7.7%, and 1.0 and 3.0% during the low and high ALA diets, respectively. Compared to the Western-style 10:1 diet, the 2:1 diet increased EPA by 60% (P < 0.0001) in RBC membranes without the direct EPA source and a 34% increase (P = 0.027) was observed with the 10:1 + S diet; however, DHA levels increased in both diet ratios only with a direct DHA source. Shifting towards a 2:1 diet is a valid alternative to taking EPA-containing supplements.     

Activin A and Cell-Surface GRP78 Are Novel Targetable RhoA Activators for Diabetic Kidney Disease

Diabetic kidney disease (DKD) is the leading cause of kidney failure. RhoA/Rho-associated protein kinase (ROCK) signaling is a recognized mediator of its pathogenesis, largely through mediating the profibrotic response. While RhoA activation is not feasible due to the central role it plays in normal physiology, ROCK inhibition has been found to be effective in attenuating DKD in preclinical models. However, this has not been evaluated in clinical studies as of yet. Alternate means of inhibiting RhoA/ROCK signaling involve the identification of disease-specific activators. This report presents evidence showing the activation of RhoA/ROCK signaling both in vitro in glomerular mesangial cells and in vivo in diabetic kidneys by two recently described novel pathogenic mediators of fibrosis in DKD, activins and cell-surface GRP78. Neither are present in normal kidneys. Activin inhibition with follistatin and neutralization of cell-surface GRP78 using a specific antibody blocked RhoA activation in mesangial cells and in diabetic kidneys. These data identify two novel RhoA/ROCK activators in diabetic kidneys that can be evaluated for their efficacy in inhibiting the progression of DKD.     

Use of multiwavelength transmission spectroscopy for the characterization of Cryptosporidium parvum oocysts: quantitative interpretation

Combined scattering and absorption properties of suspended particles can be obtained as a function of wavelength by measuring the complete ultraviolet-visible (UV-vis) spectrum. This research reports on the quantitative interpretation of measured UV-vis spectra of Cryptosporidium parvum oocyst suspensions obtained from several commercial sources and evaluated using two different purification techniques. The reproducibility of the measured spectral data was assessed, and the quantitative interpretation of the oocyst spectra in terms of the particle size and the chemical composition of the particles are reported herein. The interpretation model of the spectra is based on light scattering theory, spectral deconvolution techniques, and on the approximation of the wavelength-dependent optical properties of the basic constituents of living organisms. A characteristic set of optical properties for C. parvum oocysts has been determined as a function of wavelength and used for the quantitative interpretation of UV-vis spectra. The results from the spectral deconvolution show quantitative differences among oocyst preparations. These results represent the first step in establishing a set of critical parameters (e.g., oocyst size and chemical composition) necessary for the detection and identification of C. parvum oocysts in water using spectroscopy.     

Invertase activity in fresh and processed honeys

The enzymatic activities of 147 samples of commercially produced Spanish polyfloral and monofloral honeys are reported. Important variations in invertase activity and peroxide accumulation were determined to obtain objective information related to honey quality. Variations from 4.04 (Robinia pseudoacacia) to 25.61 g sucrose hydrolysed per 100 g h⁻¹ (SN) (Castanea sativa) and from 11.31 (Erica vagans) to 45.25 µg H₂O₂ g⁻¹ h⁻¹ (Hedysarum coronarium) were detected, with a range from 10.57 to 46.2 SN in polyfloral honeys. Honeys from Erica spp had different invertase activities—high for E cinerea (18.3 SN) and low for E vagans (8.36 SN). The different heating processes of honey have been evaluated to determine the best treatment for preserving invertase activity. The hydroxymethylfurfural content is not a sufficiently good indicator of the degree of deterioration of honey. Another objective was to assess the use of invertase activity in honey quality legislation. © 2000 Society of Chemical Industry     

Quantifying water quality and flow in multi-branched urban estuaries for a rainfall event with mass balance method

In this study, field observations were conducted after a heavy rainfall event in the Sumida and Shakujii rivers in Tokyo, Japan. The flow dynamics and fluxes of salt, suspended sediment (SS), and dissolved oxygen (DO) were investigated with the mass balance method. The fractions of fresh water and saltwater in seaward and landward flows were separated. The maximum salt flux in the Shakujii River was 53.8 kg/s during the flood tide, and those in the Sumida River were 680.3 kg/s at the upstream station and 703.7 kg/s at the downstream station. The trends of SS and DO fluxes were similar in both rivers. In the Shakujii River, the highest SS (3.1 kg/s) and DO (0.4 kg/s) fluxes appeared during the flood tide after rainfall. In the Sumida River, the maximum SS fluxes (6.1 and 6.3 kg/s at the upstream and downstream stations, respectively) and DO fluxes (1.15 and 1.21 kg/s at the upstream and downstream stations, respectively) appeared during the ebb tide. The mass balance method was used to estimate discharge, salinity, SS concentration, and DO concentration at a station with missing data. The results show that the estimated salinity and SS concentration had a significant correlation with the on-site observations, with correlation coefficients (R) of 0.950 and 0.835, respectively, but not for DO concentration (R = 0.638). The disparity between the computed and measured data may be explained by the differences in velocity, salinity, topography, sedimentation, and the presence of organic matter. The analysis based on the advective salt transport components found a lower salt flux per unit width in the Shakujii River (0.36 kg/(m·s)) in comparison with that in the Sumida River (2.88 kg/(m·s)). This indicates a higher probability for salt retention in the Shakujii River.     

The effect of tetraethylammonium cation adsorption on the pzc of the mercury—perchloric acid interphase

The acid activity dependence of pzc for the mercury—perchloric acid aqueous solution interphase was studied, and the results compared with previously reported values. Then, the pzc shift caused by tetraethylammonium (TEA) perchlorate addition to constant activity perchloric acid solutions is reported, and an expression for the Esin—Markov coefficient is given. The need for using activity values is discussed on the basis of quantitive data.