Unassisted solar lignin valorisation using a compartmented photo-electro-biochemical cell

Lignin is a major component of lignocellulosic biomass. Although it is highly recalcitrant to break down, it is a very abundant natural source of valuable aromatic carbons. Thus, the effective valorisation of lignin is crucial for realising a sustainable biorefinery chain. Here, we report a compartmented photo-electro-biochemical system for unassisted, selective, and stable lignin valorisation, in which a TiO2 photocatalyst, an atomically dispersed Co-based electrocatalyst, and a biocatalyst (lignin peroxidase isozyme H8, horseradish peroxidase) are integrated, such that each system is separated using Nafion and cellulose membranes. This cell design enables lignin valorisation upon irradiation with sunlight without the need for any additional bias or sacrificial agent and allows the protection of the biocatalyst from enzymedamaging elements, such as reactive radicals, gas bubbles, and light. The photo-electrobiochemical system is able to catalyse lignin depolymerisation with a 98.7% selectivity and polymerisation with a 73.3% yield using coniferyl alcohol, a lignin monomer

Inequities in maternal postnatal visits among public and private patients: 2004 Pelotas cohort study

<p>Abstract</p> <p>Background</p> <p>The postnatal period is the ideal time to deliver interventions to improve the health of both the newborn and the mother. However, postnatal care shows low-level coverage in a large number of countries. The objectives of this study were to: 1) investigate inequities in maternal postnatal visits, 2) examine differences in postnatal care coverage between public and private providers and 3) explore the relationship between the absence of maternal postnatal visits and exclusive breastfeeding, use of contraceptive methods and maternal smoking three months after birth.</p> <p>Methods</p> <p>In the calendar year of 2004 a birth cohort study was started in the city of Pelotas, Brazil. Mothers were interviewed soon after delivery and at three months after birth. The absence of postnatal visits was defined as having no consultations between the time of hospital discharge and the third month post-partum. Logistic regression analysis was used to estimate the association between absence of postnatal visits and type of insurance scheme adjusting for potential confounding factors.</p> <p>Results</p> <p>Poorer women, black/mixed, those with lower level of education, single mothers, adolescents, multiparae, smokers, women who delivered vaginally and those who were not assisted by a physician were less likely to attend postnatal care. Postnatal visits were also less frequent among women who relied in the public sector than among private patients (72.4% vs 96% among public and private patients, respectively, <it>x</it>²p < 0.001) and this difference was not explained either by maternal characteristics or by health care utilization patterns. Women who attended postnatal visits were more likely to exclusively breastfeed their infants, to use contraceptive methods and to be non-smokers three months after birth.</p> <p>Conclusion</p> <p>Postpartum care is available for every woman free of charge in the Brazilian Publicly-funded health care system. However, low levels of postpartum care were seen in the study (77%). Efforts should be made to increase the percentage of women receiving postpartum care, particularly those in socially disadvantaged groups. This could include locally-adapted health education interventions that address women's beliefs and attitudes towards postpartum care. There is a need to monitor postpartum care and collected data should be used to guide policies for health care systems.</p

D-β-Hydroxybutyrate Is Protective in Mouse Models of Huntington's Disease

Abnormalities in mitochondrial function and epigenetic regulation are thought to be instrumental in Huntington's disease (HD), a fatal genetic disorder caused by an expanded polyglutamine track in the protein huntingtin. Given the lack of effective therapies for HD, we sought to assess the neuroprotective properties of the mitochondrial energizing ketone body, D-β-hydroxybutyrate (DβHB), in the 3-nitropropionic acid (3-NP) toxic and the R6/2 genetic model of HD. In mice treated with 3-NP, a complex II inhibitor, infusion of DβHB attenuates motor deficits, striatal lesions, and microgliosis in this model of toxin induced-striatal neurodegeneration. In transgenic R6/2 mice, infusion of DβHB extends life span, attenuates motor deficits, and prevents striatal histone deacetylation. In PC12 cells with inducible expression of mutant huntingtin protein, we further demonstrate that DβHB prevents histone deacetylation via a mechanism independent of its mitochondrial effects and independent of histone deacetylase inhibition. These pre-clinical findings suggest that by simultaneously targeting the mitochondrial and the epigenetic abnormalities associated with mutant huntingtin, DβHB may be a valuable therapeutic agent for HD

MONITORING THE EJECTION AND INCORPORATION OF FE(CN)6(3-) AND FE(CN)6(4-) COUNTERIONS AT PROTONATED POLY(4-VINYLPYRIDINE) COATINGS ON ELECTRODES WITH THE SCANNING ELECTROCHEMICAL MICROSCOPE

The precise positioning of microtip electrodes close to the surface of substrate electrodes, as practiced in scanning electrochemical microscopy, was exploited to monitor the concentrations of Fe(CN)6(3-) and Fe(CN)6(4-) anions at the surfaces of protonated poly(4-vinylpyridine) coatings on glassy-carbon electrodes. Positive feedback, which enhanced the magnitude of currents at the monitoring tip electrode, gave way to negative feedback when reactant concentrations were increased to the point that electron propagation through the polyelectrolyte coatings became the current-limiting step. The ejection of counterions when cathodic currents were passed through coatings which were saturated with Fe(CN)6(3-) was readily detected, especially when current steps were applled to the coated substrate electrode. Delayed arrival of counterions at the monitoring tip could be associated with the time required for the lons to traverse the coatings before they were ejected. Reincorporation of multiply-charged counterions immediately following their ejection appeared to be favored over the incorporation of singly charged anions present at much higher concentrations.This work was supported by the National Science Foundation. This is Contribution No. 8492 from the Division of Chemistry and Chemical Engineering, California Institute of Technology

Effects of electrode surface pretreatments on the electrochemistry of a macrocyclic dioxoruthenium(VI) complex

The reductive electrochemistry of trans-[RuVI(TMC)(O)2]2+ (TMC = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane) follows different courses in aprotic and aqueous media. In acetonitrile, a one-electron reduction to trans-[RuV(TMC)(O)2]+ occurs. In aqueous acid trans-[RuIV(TMC)O(OH2)]2+ is formed in a single, two-electron, two-proton step. [RuV(TMC)(O)2]+ disproportionates to [RuVI(TMC)(O)2]2+ and [RuIV(TMC)O(OH2)]2+ in the presence of acid. The oxidation of [RuIV(TMC)O(OH2)]2+ in aqueous acid is facile at pyrolytic graphite and oxidatively "activated" glassy carbon electrodes but hindered at unactivated glassy carbon, platinum and gold electrodes. Slow proton transfer is identified as the origin of the slow oxidation and oxygen-containing groups on "activated" electrodes are suggested as the catalysts for this step. © 1987.link_to_subscribed_fulltex

Monooxo complexes of ruthenium(V) as homogeneous redox catalysts for the electrooxidation of benzyl alcohol

The electrochemical behavior of three Ru(IV)-monooxo complexes, trans-[RuIV(TMC)O(X)]ClO4 (TMC = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane; X- = Cl-, NCO-, N3 -), in acetonitrile is described. The formal potentials of the Ru(V)/Ru(IV) couples decrease in the order Cl- > NCO- > N3 -. The electrochemically generated Ru(V)-monooxo complexes are active catalysts for the oxidation of benzyl alcohol to benzaldehyde. The rate of benzyl alcohol oxidation decreases in the same order as the formal potentials. The second-order rate constants for reaction between the Ru(V) complexes and benzyl alcohol were evaluated by rotating disk voltammetry. The values obtained were 2.1 × 102 and 1.4 × 102 M-1 s-1 for X- = Cl- and NCO-, respectively. The catalysts gradually lose their activity during the course of the electrooxidation of benzyl alcohol because of what appears to be decomposition of the catalysts during the period that they are in the Ru(V) oxidation state. © 1987 American Chemical Society.link_to_subscribed_fulltex

Electrochemistry of cis-diaquorutheniumII) complexes with 2,2'-bipyridine and related ligands at edge plane pyrolytic graphite electrodes. Characterization of reversible Ru(VI/V), Ru(V/IV), Ru(IV/III) and Ru(III/II) couples and catalytic oxidation by Ru(VI)

link_to_subscribed_fulltex