Epigallocatechin-3-Gallate Ameliorates Alcohol-Induced Liver Injury in Rats

Endotoxemia is a common event in alcoholic liver disease. Elevated intestinalpermeability is the major factor involved in the mechanism of alcoholic endotoxemia andthe pathogenesis of alcoholic liver disease. This study examined the effect ofepigallocatechin-3-gallate (EGCG) on alcohol-induced gut leakiness, and explored therelated mechanisms involved in its protection against alcohol-induced liver injury in rats.Four groups of female Sprague-Dawley rats were studied. Alcohol and alcohol/EGCGgroups rats received fish oil along with alcohol daily via gastrogavage for 6 weeks, anddextrose and dextrose/EGCG groups rats were given fish oil along with isocaloric dextroseinstead of alcohol. The dextrose/EGCG and alcohol/EGCG groups received additionaltreatment of EGCG (100mg.kg-1 body weight) daily intragastrically by gavage. Intestinalpermeability was assessed by urinary excretion of lactulose and mannitol (L/M ratio). Liverinjury was evaluated histologically and by serum alanine aminotransferase (ALT). Plasmaendotoxin and serum tumor necrosis factor-α (TNF-α) levels were assayed; livermalondialdehyde (MDA) contents determined. CD14 and inflammatory factors, such asTNF-α, cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) mRNAs inthe liver were analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR). Ratsgiven fish oil plus alcohol had gut leakiness (L/M ratio was increased), which wasassociated with both endotoxemia and liver injury. The above responses were accompaniedby increased CD14, TNF-α, COX-2 and iNOS mRNA expressions in the liver. EGCGsupplementation partly blocked the gut leakiness, reduced endotoxemia and lipidperoxidation, and blunted the elevated expressions of CD14, TNF-α, COX-2 and iNOS, allof which were associated with improved liver injury. These results show that EGCG can block alcohol-induced gut leakiness, reduce endotoxemia, and inhibit inflammatory factors expressions in the liver, thereby ameliorates alcohol-induced liver injury

A review on performance degradation of proton exchange membrane fuel cells during startup and shutdown processes : causes, consequences, and mitigation strategies

Performance degradation during startup and shutdown is considered an important issue affecting the durability and lifetime of proton exchange membrane fuel cells (PEMFCs). Due to the high potentials experienced by the cathode during startup and shutdown, the conventional carbon support for the cathode catalyst is prone to oxidation by reacting with oxygen or water. This paper presents an overview of the causes and consequences of performance degradation after frequent startup shutdown cycles. Mitigation strategies are also summarized, including the use of novel catalyst supports and the application of system strategies to prevent performance degradation in PEMFCs. It is found from the literature review that improvements in catalyst supports to prevent oxidation come at the expense of high cost, and the novel supports developed to date are not sufficient to completely prevent carbon oxidation in fuel cell engines. System strategies, including potential control and reaction gas control, have been developed and applied in fuel cell engines to alleviate or even avoid performance decay. This review aims to provide a clear understanding of the mechanisms related to degradation behaviors during the startup and shutdown processes, thereby helping fuel cell material or system developers in their efforts to prevent performance degradation and prolong the lifetime of PEMFCs.Peer reviewed: YesNRC publication: Ye

Synthesis of polyoxometalates derived bifunctional catalyst towards efficient overall water splitting in neutral and alkaline medium

The development of efficient hydrogen evolution and oxygen evolution reactions bifunctional electrocatalyst for overall water splitting is highly desired but still a great challenge, especially under neutral condition. With the unique properties of polyoxometalate and MOFs materials as well as rich transition metal contents, herein we successfully synthesize a novel bi-phase structure of cobalt and molybdenum carbide coated with nitrogen-doped graphite (Co-Mo2C@NC) which possesses excellent activity as water splitting electrocatalyst at neutral pH. This noble metal-free, bi-phase electrocatalyst exhibits Hydrogen Evolution Reaction (HER) and Oxygen Evolution Reaction (OER) overpotentials of 260 mV and 440 mV at 10 mA cm(-2), respectively. The two-electrode system using Co-Mo2C@NC as both the anode and cathode drives 10 mA cm(-2) at a cell voltage of 1.83 V with a remarkable long-term stability. Besides, the Co-Mo2C@NC also shows promising activity in alkaline condition that reaches 10 mA cm(-2) at a cell voltage of 1.66 V. This work paves a new avenue to the design of the unique, economic and promising non-noble metal electrode materials for practical applications in the electrochemical energy storage and conversion devices. (C) 2018 Elsevier Inc. All rights reserved

Gadolinium polytungstate nanoclusters: a new theranostic with ultrasmall size and versatile properties for dual-modal MR/CT imaging and photothermal therapy/radiotherapy of cancer

The development of a new generation of nanoscaled theranostics with simple compositions and versatile properties to realize enhanced diagnoses and treatment outcomes and to avoid side effects is highly desirable but remains a great challenge. Here we report a new ultrasmall theranostic based on bovine serum albumin-coated GdW10O36 nanoclusters (GdW10NCs) as multifunctional theranostics for multifunctional bio-imaging, highly effective in vitro photothermal ablation of cancer cells and in vivo radiotherapy of tumors. The as-synthesized GdW10 NCs afford significantly enhanced computed tomography/magnetic resonance imaging signals and remarkable photothermal therapy (PTT)/radiotherapy therapy (RT) therapeutic effects for tumor treatment. Moreover, toxicity studies confirmed their low toxicity and efficient renal clearance, suggesting their potential for practical applications. These results indicated that the as-prepared GdW10 nanoclusters are promising as multifunctional nanotheranostics for multimodal imaging-guided PTT/RT of tumors. These results also encourage the further exploration of other polyoxometalate-based multifunctional nanotheranostics for cancer diagnoses and therapy

Epigallocatechin-3-gallate ameliorates alcohol-induced liver injury in rats

Abstract: Endotoxemia is a common event in alcoholic liver disease. Elevated intestinal permeability is the major factor involved in the mechanism of alcoholic endotoxemia and the pathogenesis of alcoholic liver disease. This study examined the effect of epigallocatechin-3-gallate (EGCG) on alcohol-induced gut leakiness, and explored the related mechanisms involved in its protection against alcohol-induced liver injury in rats. Four groups of female Sprague-Dawley rats were studied. Alcohol and alcohol/EGCG groups rats received fish oil along with alcohol daily via gastrogavage for 6 weeks, and dextrose and dextrose/EGCG groups rats were given fish oil along with isocaloric dextrose instead of alcohol. The dextrose/EGCG and alcohol/EGCG groups received additional treatment of EGCG (100mg.kg-1 body weight) daily intragastrically by gavage. Intestinal permeability was assessed by urinary excretion of lactulose and mannitol (L/M ratio). Liver injury was evaluated histologically and by serum alanine aminotransferase (ALT). Plasma endotoxin and serum tumor necrosis factor-α (TNF-α) levels were assayed; liver malondialdehyde (MDA) contents determined. CD14 and inflammatory factors, such as TNF-α, cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) mRNAs i

Current mapping of a proton exchange membrane fuel cell with a segmented current collector during the gas starvation and shutdown processes

Current distribution during the gas starvation and shutdown processes is investigated in a proton exchange membrane fuel cell with an active area of 184 cm\ub2. The cell features a segmented cathode current collector. The response characteristics of the segmented single cell under different degrees of hydrogen and air starvation are explored. The current responses of the segment cells at different positions under a dummy load in the shutdown process are reported for various operating conditions, such as different dummy loads, cell temperatures, and gas humidities under no back pressure. The results show that applying a dummy load during the cell shutdown process can quickly reduce the cell potential and thereby avoid the performance degradation caused by high potentials. The currents of all the segment cells decrease with time, but the rate of decrease varies with the segment cell positions. The rate for the segment cells near the gas outlet is much higher than that of the segment cells near the gas inlet. The current of the segment cells decreases much more quickly at a lower gas humidity and high temperature. This study provides insights in the development of mitigation strategies for the degradation caused by starvation and shutdown process.Peer reviewed: YesNRC publication: Ye

Tuning carbon nanotube-grafted core-shell-structured cobalt selenide@carbon hybrids for efficient oxygen evolution reaction

The electrochemical oxygen evolution reaction (OER) is sparked extensive interest in efficient energy storage and conversion. Cobalt Selenide (CoSe2) is believed to be one of the promising candidates for OER based on Yang Shao-Horn's principle. However, owing to low exposure of active sites and/or low efficiency of electron transfer, the electrocatalytic activity of CoSe2 is far less than expected. In this work, a novel carbon nanotubes (CNT) grafted 3D core-shell structured CoSe2@C-CNT nanohybrid is developed by a general hydrothermal-calcination strategy. Zeolite imidazole frameworks (ZIF) was used as the precursor to synthesis of the materials. It is found that both the calcination temperature and the selenium content can significantly regulate the catalytic performance of the hybrids. The obtained best catalysts requires the overpotential of only 306 mV and 345 mV to reach a current density of 10 mA cm(-2) and 50 mA cm(-2) in 1.0 MKOH medium, respectively. It also exhibits a small Tafel slope of 46 mV dec(-1) and excellent durability, which is superior to most of recently reported CoSe2-based and Co-based materials. These superior performances can be ascribed to synergistic effects of the highly active CoSe2 nanostructure, defect carbon species and the carbon nanotubes exist in the catalyst. Besides, the unique morphology leads to large electrochemical surface area of the catalyst, which is in favor of the exposure of active sites for OER. Due to high efficiency, low cost and excellent durability for OER, the prepared catalysts showed can be potentially used to substitute noble metals utilized in related energy storage and conversion devices. (C) 2018 Elsevier Inc. All rights reserved

Br/Co/N Co-doped porous carbon frameworks with enriched defects for high-performance electrocatalysis

Defect engineering through heteroatom doping is one of the most important strategies towards the development of catalytic active materials for energy related applications. Herein, a novel trifunctional Br/Co/N Co-doped and defect-enriched porous carbon framework (BrHT@CoNC) is designed, which shows excellent electrocatalytic activity for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) as well as the hydrogen evolution reaction (HER). Introduction of extensive defects by heteroatom-doping is simply achieved by pyrolysis of the surfactant, dimethyldioctadecylammonium bromide (DODAB) modified ZIF-67. The BrHT@CoNC composite shows great potential as an economical catalyst/electrode for both rechargeable Zn-air batteries and overall water splitting devices. This work opens a new avenue toward the exploration of cost effective heteroatom doped catalysts for efficient integration of three or more functions into one freestanding electrode.</p

Characterization and virulence clustering analysis of extraintestinal pathogenic Escherichia coli isolated from swine in China

Abstract Background Swine extraintestinal pathogenic Escherichia coli (ExPEC) is an important pathogen that leads to economic and welfare costs in the swine industry worldwide, and is occurring with increasing frequency in China. By far, various virulence factors have been recognized in ExPEC. Here, we investigated the virulence genotypes and clonal structure of collected strains to improve the knowledge of phylogenetic traits of porcine ExPECs in China. Results We isolated 64 Chinese porcine ExPEC strains from 2013 to 14 in China. By multiplex PCR, the distribution of isolates belonging to phylogenetic groups B1, B2, A and D was 9.4%, 10.9%, 57.8% and 21.9%, respectively. Nineteen virulence-related genes were detected by PCR assay; ompA, fimH, vat, traT and iutA were highly prevalent. Virulence-related genes were remarkably more prevalent in group B2 than in groups A, B1 and D; notably, usp, cnf1, hlyD, papA and ibeA were only found in group B2 strains. Genotyping analysis was performed and four clusters of strains (named I to IV) were identified. Cluster IV contained all isolates from group B2 and Cluster IV isolates had the strongest pathogenicity in a mouse infection model. As phylogenetic group B2 and D ExPEC isolates are generally considered virulent, multilocus sequence typing (MLST) analysis was performed for these isolates to further investigate genetic relationships. Two novel sequence types, ST5170 and ST5171, were discovered. Among the nine clonal complexes identified among our group B2 and D isolates, CC12 and CC95 have been indicated to have high zoonotic pathogenicity. The distinction between group B2 and non-B2 isolates in virulence and genotype accorded with MLST analysis. Conclusion This study reveals significant genetic diversity among ExPEC isolates and helps us to better understand their pathogenesis. Importantly, our data suggest group B2 (Cluster IV) strains have the highest risk of causing animal disease and illustrate the correlation between genotype and virulence