Simple metal oxides as efficient heterogeneous catalysts for epoxidation of alkenes by molecular oxygen

Magnetite iron oxide (Fe3O4) has been found to be an efficient heterogeneous catalyst for the epoxidation of alkenes by molecular oxygen in the absence of a sacrificial reductant among various transition metal oxides. The reaction probably proceeds via a radical mechanism

Luminescent properties of Bi-doped polycrystalline KAlCl4

We observed an intensive near-infrared luminescence in Bi-doped KAlCl4 polycrystalline material. Luminescence dependence on the excitation wavelength and temperature of the sample was studied. Our experimental results allow asserting that the luminescence peaked near 1 um belongs solely to Bi+ ion which isomorphically substitutes potassium in the crystal. It was also demonstrated that Bi+ luminescence features strongly depend on the local ion surroundings

Co3O4 Nanocrystals on Graphene as a Synergistic Catalyst for Oxygen Reduction Reaction

Catalysts for oxygen reduction and evolution reactions are at the heart of key renewable energy technologies including fuel cells and water splitting. Despite tremendous efforts, developing oxygen electrode catalysts with high activity at low costs remains a grand challenge. Here, we report a hybrid material of Co3O4 nanocrystals grown on reduced graphene oxide (GO) as a high-performance bi-functional catalyst for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). While Co3O4 or graphene oxide alone has little catalytic activity, their hybrid exhibits an unexpected, surprisingly high ORR activity that is further enhanced by nitrogen-doping of graphene. The Co3O4/N-doped graphene hybrid exhibits similar catalytic activity but superior stability to Pt in alkaline solutions. The same hybrid is also highly active for OER, making it a high performance non-precious metal based bi-catalyst for both ORR and OER. The unusual catalytic activity arises from synergetic chemical coupling effects between Co3O4 and graphene.Comment: published in Nature Material

SiC Nanowires Synthesized by Rapidly Heating a Mixture of SiO and Arc-Discharge Plasma Pretreated Carbon Black

SiC nanowires have been synthesized at 1,600 °C by using a simple and low-cost method in a high-frequency induction furnace. The commercial SiO powder and the arc-discharge plasma pretreated carbon black were mixed and used as the source materials. The heating-up and reaction time is less than half an hour. It was found that most of the nanowires have core-shell SiC/SiO2nanostructures. The nucleation, precipitation, and growth processes were discussed in terms of the oxide-assisted cluster-solid mechanism

Fibrillization of Human Tau Is Accelerated by Exposure to Lead via Interaction with His-330 and His-362

and its mutants at physiological pH. interaction with His-330 and His-362, with sub-micromolar affinity. in the pathogenesis of Alzheimer disease and provide critical insights into the mechanism of lead toxicity

The Epitope and Neutralization Mechanism of AVFluIgG01, a Broad-Reactive Human Monoclonal Antibody against H5N1 Influenza Virus

The continued spread of highly pathogenic avian influenza (HPAI) H5N1 virus underscores the importance of effective antiviral approaches. AVFluIgG01 is a potent and broad-reactive H5N1-neutralizing human monoclonal antibody (mAb) showing great potential for use either for therapeutic purposes or as a basis of vaccine development, but its antigenic epitope and neutralization mechanism have not been finely characterized. In this study, we first demonstrated that AVFluIgG01 targets a novel conformation-dependent epitope in the globular head region of H5N1 hemagglutinin (HA). By selecting mimotopes from a random peptide library in combination with computational algorithms and site-directed mutagenesis, the epitope was mapped to three conserved discontinuous sites (I-III) that are located closely at the three-dimensional structure of HA. Further, we found that this HA1-specific human mAb can efficiently block both virus-receptor binding and post-attachment steps, while its Fab fragment exerts the post-attachment inhibition only. Consistently, AVFluIgG01 could inhibit HA-mediated cell-cell membrane fusion at a dose-dependent manner and block the acquisition of pH-induced protease sensitivity. These results suggest a neutralization mechanism of AVFluIgG01 by simultaneously blocking viral attachment to the receptors on host cells and interfering with HA conformational rearrangements associated with membrane fusion. The presented data provide critical information for developing novel antiviral therapeutics and vaccines against HPAI H5N1 virus

Disparities and risks of sexually transmissible infections among men who have sex with men in China: a meta-analysis and data synthesis.

BACKGROUND: Sexually transmitted infections (STIs), including Hepatitis B and C virus, are emerging public health risks in China, especially among men who have sex with men (MSM). This study aims to assess the magnitude and risks of STIs among Chinese MSM. METHODS: Chinese and English peer-reviewed articles were searched in five electronic databases from January 2000 to February 2013. Pooled prevalence estimates for each STI infection were calculated using meta-analysis. Infection risks of STIs in MSM, HIV-positive MSM and male sex workers (MSW) were obtained. This review followed the PRISMA guidelines and was registered in PROSPERO. RESULTS: Eighty-eight articles (11 in English and 77 in Chinese) investigating 35,203 MSM in 28 provinces were included in this review. The prevalence levels of STIs among MSM were 6.3% (95% CI: 3.5-11.0%) for chlamydia, 1.5% (0.7-2.9%) for genital wart, 1.9% (1.3-2.7%) for gonorrhoea, 8.9% (7.8-10.2%) for hepatitis B (HBV), 1.2% (1.0-1.6%) for hepatitis C (HCV), 66.3% (57.4-74.1%) for human papillomavirus (HPV), 10.6% (6.2-17.6%) for herpes simplex virus (HSV-2) and 4.3% (3.2-5.8%) for Ureaplasma urealyticum. HIV-positive MSM have consistently higher odds of all these infections than the broader MSM population. As a subgroup of MSM, MSW were 2.5 (1.4-4.7), 5.7 (2.7-12.3), and 2.2 (1.4-3.7) times more likely to be infected with chlamydia, gonorrhoea and HCV than the broader MSM population, respectively. CONCLUSION: Prevalence levels of STIs among MSW were significantly higher than the broader MSM population. Co-infection of HIV and STIs were prevalent among Chinese MSM. Integration of HIV and STIs healthcare and surveillance systems is essential in providing effective HIV/STIs preventive measures and treatments. TRIAL REGISTRATION: PROSPERO NO: CRD42013003721

Organochlorine Pesticides in Consumer Fish and Mollusks of Liaoning Province, China: Distribution and Human Exposure Implications

Fish and mollusk samples were collected from markets located in 12 cities in Liaoning province, China, during August and September 2007, and 22 organochlorine pesticides (OCPs) were detected. DDT, HCH, endosulfan, chlordane, and HCB were the dominating OCPs, with mean concentrations and ranges of, respectively, 15.41 and 0.57 to 177.56 ng/g, 0.84 and below detection limit (BDL) to 22.99 ng/g, 1.31 and BDL to 13.1 ng/g, 1.05 and BDL to 15.68 ng/g, and 0.63 and BDL to 9.21 ng/g in all fish and mollusk samples. The concentrations of other OCPs generally were low and were detectable in a minority of samples, reflecting the low levels of these OCPs in the study region. In general, OCP concentrations were obviously higher in fish than in mollusks, and higher in freshwater fish than in marine fish, which indicated, first, that freshwater fish are more easily influenced than seawater fish and mollusks by OCP residues in agricultural areas and, second, that there are different biota accumulation factors for OCPs between fish and mollusk. To learn the consumption of fish and mollusk, 256 questionnaires were sent to families in 12 cities of Liaoning province. Using the contamination data, average estimated daily intakes of OCPs via fish and mollusk consumption were calculated, which were used for exposure assessment. The public health risks caused by exposure to OCPs in the course of fish and mollusk consumption were compared to noncancer benchmarks and cancer benchmarks