Earth abundant materials beyond transition metal dichalcogenides: A focus on electrocatalyzing hydrogen evolution reaction

The depletion of the unsustainable fossil fuels drives the exploration of renewable and clean energy. Hydrogen gas, as the potential alternative for the future energy supply, is now considered as the primary choice. Recently, with the assistance of the non-noble metal based compounds, electrocatalytic hydrogen evolution has aroused tremendous attention. In particular, earth abundant materials beyond transition metal dichalcogenides, such as transition metal phosphides, carbides, nitrides, demonstrate highly active and efficient activity toward hydrogen evolution reaction (HER) under different conditions. In this review, focused on these materials, we systemically discuss their recent development in electrocatalytic hydrogen generation. The synthesis routes utilized to prepare superior and specific catalyst are highlighted. Then, we provide insight into the characterization and electrochemical performance of these materials as HER electrocatalysts. In the end, the challenges of these materials, important issues about studying eletablctrocatalysts and future perspectives are stressed

Optical generation of hybrid entangled state via entangling single-photon-added coherent state

We propose a feasible scheme to realize the optical entanglement of single-photon-added coherent state (SPACS) and show that, besides the Sanders entangled coherent state, the entangled SPACS also leads to new forms of hybrid entanglement of quantum Fock state and classical coherent state. We probe the essential difference of two types of hybrid entangled state (HES). This HES provides a novel link between the discrete- and the continuous-variable entanglement in a natural way.Comment: 6 pages, 2 figure

A new strategy to enhance polysialic acid production by controlling sorbitol concentration in cultivation of Escherichia coli K235

Polysialic acid (PSA) is a new pharmaceutical material used in control release of protein drugs and as scaffold material in biomedical applications. It is also a vital source of sialic acid and its derivatives. In this paper, we demonstrated that the substrate sorbitol has significant effect on bacterial growth and PSA formation in cultivation of Escherichia coli K235. Lower sorbitol concentration favored bacterial growth but retards PSA formation in the fed-batch fermentation. Higher sorbitol concentration stimulated PSA formation but inhibited bacterial growth in the batch fermentation. Sorbitol concentration gradient experiment revealed that PSA formation was seriously limited as sorbitol concentration was lower than 20 g/L, while bacterial growth was obviously inhibited as the sorbitol concentration higher than 40 g/L. A new strategy of controling sorbitol concentration in a range of 20 - 40 g/L in the broth during the fermentation process increased PSA yield by 20%

The stability of transgene expression and effect of DNA methylation on post transcriptional gene silencing (PTGS) in birch

In this paper, we selected transgenic birch (Betula platyphylla Suk) plants, which included nonsilencing plants, transcriptional silence plants including TP96, TP74, TP73 and the post-transcriptional silence ones (TP67 and TP72). The transcription of the bgt gene in different tissues and organs were significantly different. The transcriptional level of bgt gene in the different tissues and organs was in the following order: leaf > female flower and male flower > branch bark > phloem > root. The transgenic lines were monitored for foreign gene expression for a long-term period of 8 years during their continuous growth under field conditions. GUS protein expression was not reactivated in the transgene silencing lines TP72 and TP67 when cultured in field conditions for long-term period. Meanwhile, no cases of gene silencing were observed again during the study period in the field conditions. Our results suggest that transgene expression in transgenic birch plants appears to be stable under field conditions. The frequencies of methylated cytosines in the code regions of gus gene was studied. Relation of transgene expression and DNA methylation was analysed. The data of restriction enzyme digestion (HpaII and MspI) indicated that DNA methylation resulted in post transcriptional gene silencing (PTGS) in transgenic birch.Key words: Transgenic birch, DNA methylation, gene silencing

Effect of Ultra-high Pressure Treatment on the Chemical Properties, Colour and Sensory Quality of Young Red Wine

The effects of ultra-high pressure (UHP) treatment on the chemical properties, colour and sensory qualityof young red wine were studied. UHP did not significantly affect the alcohol content, and the methanolcontent was higher than that of the control, with the latter first increasing and then decreasing with theincrease in the pressure or period of treatment. The glycerol content was also markedly changed by UHP,although without a regular pattern. The pH value was not markedly changed by the treatments, and thecontents of total acids and volatile acids were scarcely affected. The fructose and glucose contents wereclearly changed according to the different treatment conditions. The tartaric acid, citric acid and lacticacid levels showed evident changes, whereas the malic acid level was not changed by UHP treatment. Thetrend of these changes was similar to what occurs during natural ageing. As the pressure of the treatmentwas increased to 200 MPa, the chroma value increased, followed by a decline upon higher pressuretreatments. The hue of the wine was significantly changed by treatment at different pressures, reachingthe highest value after treatment at 400 MPa and then decreasing with increasing pressure. The chromaand hue values of the wine were changed significantly according to the duration of the UHP. After UHP, theappearance, aroma and taste of the wine was improved, with the score for appearance obviously increased.When the wine was treated at 500 MPa for 30 min, its sensory quality received the highest score

Probing Spin-Flip Scattering in Ballistic Nanosystems

Because spin-flip length is longer than the electron mean-free path in a metal, past studies of spin-flip scattering are limited to the diffusive regime. We propose to use a magnetic double barrier tunnel junction to study spin-flip scattering in the nanometer sized spacer layer near the ballistic limit. We extract the voltage and temperature dependence of the spin-flip conductance Gs in the spacer layer from magnetoresistance measurements. In addition to spin scattering information including the mean-free path (70 nm) and the spin-flip length (1:0–2:6 m) at 4.2 K, this technique also yields information on the density of states and quantum well resonance in the spacer laye

Endothelial Cell Cortactin Phosphorylation by Src Contributes to Polymorphonuclear Leukocyte Transmigration In Vitro

The underlying mechanisms that regulate leukocyte transendothelial migration through the vascular endothelium remain unclear. Cortactin is a substrate of Src tyrosine kinases and a regulator of cytoskeletal dynamics. Previous studies demonstrated a role for Src phosphorylation of cortactin in clustering of E-selectin and intercellular cell adhesion molecule-1 around adherent leukocytes. In the current study, we used an in vitro flow model to investigate the role of Src-induced cortactin phosphorylation in endothelium during polymorphonuclear leukocyte (PMN) transmigration through human umbilical vein endothelium (HUVEC) monolayers preactivated with tumor necrosis factor-{alpha}. Inhibition of Src in HUVEC using Src kinase inhibitors PP2 and SU6656 reduced PMN transmigration by 45±8% and 36±6%, respectively. Live cell imaging of green fluorescent protein–tagged cortactin in HUVEC revealed redistribution of cortactin in the region surrounding transmigrating PMN. Knockdown of cortactin in HUVEC by small interfering RNA also impaired transmigration to a similar degree, and this phenotype was rescued by reexpression of wild-type cortactin. Analysis of the location of initial arrest and locomotion of PMN adherent to HUVEC demonstrated that inhibition of Src tyrosine kinases or pretreatment with cortactin small interfering RNA reduced PMN transmigration at endothelial cell-to-cell junctions and not adhesion. Tyrosine phosphorylation of cortactin was important for transmigration, because expression of a mutant, in which the tyrosine phosphorylation sites were mutated to phenylalanine (cortactin3F), failed to rescue PMN transmigration. Moreover, expression of cortactin3F alone partially blocked PMN transmigration. These data suggest a model whereby tyrosine phosphorylation of cortactin by Src family kinases regulates PMN transmigratio