A Bilayer Structure Composed of Mg|Co-MnO2 Deposited on a Co(OH)2 Film to Realize Selective Oxygen Evolution from Chloride-Containing Water.

A fluorine-doped tin oxide-coated glass electrode modified with a bilayer film of underlying α-Co(OH)2 and overlying Mg-intercalated and Co-doped δ-type (layered) MnO2 (Mg|Co-MnO2) preferentially yielded oxygen with a Faradaic efficiency as high as 79% in the presence of chloride ions at high concentration (0.5 M). This noble metal-free electrode was fabricated by cathodic electrolysis of aqueous Co(NO3)2 followed by anodic electrolysis of a mixture of Mn2+, Co2+, and cetyltrimethylammonium (CTA+) ions in water. The CTA+ ions accommodated in the interlayer spaces of Co-doped δ-MnO2 were replaced with Mg2+ by ion exchange. The upper Mg|Co-MnO2 could effectively block the permeation of Cl- ions and allow only H2O and O2, while the under α-Co(OH)2 acted as an oxidation catalyst for the H2O penetrated through the upper coating. Thus, the oxygen evolution reaction (OER) was preferred to the chlorine evolution reaction (CER). In artificial seawater (pH 8.3), the blocking effect against Cl- decreased because of ion exchange of the intercalated Mg2+ ions with Na+ in solution, but the OER efficiency still remained at 57%, much higher than that (28%) without the upper Mg|Co-MnO2. This demonstrates that the interlayer spaces between MnO2 layers acted as pathways for H2O molecules to reach the active sites of the underlying Co(OH)2. Density functional theory (DFT) calculations revealed that the most stable structure of hydrated Mg2+ ion, in which a part of coordinated H2O molecules is hydrolyzed, has less affinity toward Cl- ion than that of hydrated Na+ ion.

Characterization of Aquimarina hainanensis isolated from diseased mud crab Scylla serrata larvae in a hatchery.

Mass mortality due to necrosis signs occurred in hatchery-reared zoea stage larvae of the mud crab Scylla serrata in Okinawa, Japan, and a causative bacterium was isolated. In this study, we identified and characterized the bacterium by genome analysis, biochemical properties and pathogenicity. The bacterium was a Gram-negative, non-motile, long rod, forming yellow colonies on a marine agar plate. It grew at 20-33°C (not at 37°C) and degraded chitin and gelatin. Phylogenetic analysis of the 16S rRNA gene sequence identified the bacterium as Aquimarina hainanensis. Genome sequence data obtained from Illumina MiSeq generated 29 contigs with 3.56 Mbp in total length and a G + C content of 32.5%. The predicted 16 chitinase genes, as putative virulence factors, had certain homologies with those of genus Aquimarina. Experimental infection with the bacterium conducted on larvae of four crustacean species, brine shrimp Artemia franciscana, freshwater shrimp Caridina multidentata, swimming crab Portunus trituberculatus and mud crab S. serrata, revealed that this bacterium was highly virulent to these species. The present study suggests that the bacterium caused mass mortality in mud crab seed production was A. hainanensis and can be widely pathogenic to crustaceans.

Genetic polymorphisms of CYP17A1 in steroidogenesis pathway are associated with risk of progression to castration-resistant prostate cancer in Japanese men receiving androgen deprivation therapy.

BACKGROUND: Hormone ablation therapy is the standard therapy for prostate cancer; however, there are large individual differences in the duration of response to the therapy. We investigated, in this retrospective multicenter study, the association between genetic polymorphic variations in steroidogenesis-related genes and the risk of progression to castration-resistant prostate cancer (CRPC) in Japanese patients after androgen deprivation therapy. METHODS: Two hundred and fourteen Japanese patients with prostate cancer who were receiving androgen deprivation therapy were enrolled in this study. We investigated 22 single-nucleotide polymorphisms (SNPs) from 8 genes related to steroidogenesis. The SNPs were assayed by polymerase chain reaction (PCR)-based methods. The different genotypes in this cohort were analyzed according to a case-control status of progression to CRPC at the median duration of hormonal therapy. A logistic regression method with adjustments for patients' characteristics was applied for the analysis.After applying the logistic regression method, we performed Cox regression analysis, following Kaplan-Meier and log-rank analyses. RESULTS: In the logistic regression analysis four genetic polymorphisms, rs743572, rs6162, rs6163, and rs1004467, in the CYP17A1 gene were significantly associated with a risk of progression to CRPC (p < 0.05). Cox regression analysis for these SNPs showed an association of risk of progression to CRPC with the rs743572 genotype (p = 0.02, odds ratio [OR] 0.43, 95 % confidence interval [CI] 0.22-0.85). CONCLUSION: The genetic backgrounds for CYP17A1 genes could influence the progression of prostate cancer to CRPC after androgen deprivation therapy.

Synthesis, structure and luminescence studies of Eu(III), Tb(III), Sm(III), Dy(III) cationic complexes with acetylacetone and bis(5-(pyridine-2-yl)-1,2,4-triazol-3-yl)propane.

Studies concerning synthesis, structure and luminescence of eight-coordinate Eu, Tb, Sm and Dy complexes of the type [Ln(acac)2(L)]Cl (Hacac = pentanedione-2,4 and L = bis(5-(pyridine-2-yl)-1,2,4-triazol-3-yl)propane) are reported in detail. The obtained complexes were investigated by various means including elemental- and thermogravimetric analysis, IR- and electron transition spectroscopy. The structure of the Tb complex was determined by single-crystal X-ray crystallography: Tb is eight-coordinate, and L acting only as a tetradentate chelate together with two bidentate acac ligands. Photophysical studies of the complexes were carried out. The Tb(III) and Eu(III) complexes show strong emissions both in solid state and solution. The intensity of the luminescence of Dy(III) and Sm(III) are relatively weak. The factors determining the intensity of the photoluminescence are discussed.

Layered Manganese Dioxide Thin Films Intercalated with Ag+ Ions Reduceable In Situ for Oxygen Reduction Reaction.

The purpose of this study is to propose a new strategy based on electrodeposition to create binder-free composites of metallic silver supported on MnO2. The process involves in situ reduction of the Ag+ ions incorporated in the interlayer spaces of layered MnO2 in an alkaline electrolyte without Ag+ ions. The reduction process of the incorporated Ag+ was monitored in situ based on the characteristic surface plasmon resonance in the visible region, and the resulting metallic Ag was identified by X-ray photoelectron spectroscopy. Because the formation of metallic Ag is only possible via electron injection into the Ag+ ions between MnO2 layers, the growth of Ag metals was inevitably limited, although the reduced Ag did not remain immobilized in the interlayers of MnO2. The thus-formed Ag in the MnO2 composite functioned as an electrocatalyst for the oxygen reduction reaction in a gas diffusion electrode system, showing a much better mass activity compared to Ag particles electrodeposited from an aqueous solution containing AgNO3.

Control of secondary metabolism by farX, which is involved in the gamma-butyrolactone biosynthesis of Streptomyces lavendulae FRI-5.

The gamma-butyrolactone signaling system is distributed widely among streptomycetes as an important regulatory mechanism of antibiotic production and/or morphological differentiation. IM-2 [(2R,3R,1'R)-2-(1'-hydroxybutyl)-3-hydroxymethyl-gamma-butanolide] is a gamma-butyrolactone that switches off the production of D: -cycloserine but switches on the production of several nucleoside antibiotics as well as blue pigment in Streptomyces lavendulae FRI-5. farX is a member of the afsA-family genes, which are proposed to encode enzymes involved in gamma-butyrolactone biosynthesis. Disruption of farX caused overproduction of D: -cycloserine, and abolished production of nucleoside antibiotic and blue pigment with the loss of IM-2 production. The finding that all phenotypic changes observed in the farX disruptant were restored by the addition of exogenous IM-2 suggested that FarX plays a biosynthetic role in IM-2 production. Transcriptional comparison between the wild-type strain and the farX disruptant revealed that, in addition to already known genes farR1 and farR2, several other genes (farR4, farD, and farE) are under the transcriptional regulation of IM-2. Furthermore, the fact that farX transcription is under the control of IM-2 suggested that S. lavendulae FRI-5 has a fine-tuning system to control gamma-butyrolactone production.