Identification of Photoexcited Electron Relaxation in a Cobalt Phosphide Modified Carbon Nitride Photocatalyst

Transition metal phosphides have been recognized as efficient co-catalysts to boost the activity of semiconductor photocatalysts. However, a rigorous and quantitative understanding is still to be developed about how transition metal phosphides influence photoexcited electron dynamics. Here, we present a nanosecond time-resolved transient absorption spectroscopy (TAS) study of the photoexcited electron dynamics in carbon nitrides (g-C3N4) before and after Co and/or P modifications. Our spectroscopic study showed that Co or P lowered the initial electron density, whereas they promoted the photoexcited electron relaxation of g-C3N4, with their half-life times (t50%) of 2.5 and 1.8 ns, respectively. The formation of a CoP co-catalyst compound promoted the electron relaxation (t50%=2.8 ns) without significantly lowering the charge separation efficiency. Density functional theory (DFT) calculations were undertaken to explore the underlying fundamental reasons and they further predicted that CoP, compared to Co or P modification, better facilitates photoexcited electron transfer from g-C3N4 to reactants

Facile synthesis of precious-metal single-site catalysts using organic solvents

Single-site catalysts can demonstrate high activity and selectivity in many catalytic reactions. The synthesis of these materials by impregnation from strongly oxidizing aqueous solutions or pH-controlled deposition often leads to low metal loadings or a range of metal species. Here, we demonstrate that simple impregnation of the metal precursors onto activated carbon from a low-boiling-point, low-polarity solvent, such as acetone, results in catalysts with an atomic dispersion of cationic metal species. We show the generality of this method by producing single-site Au, Pd, Ru and Pt catalysts supported on carbon in a facile manner. Single-site Au/C catalysts have previously been validated commercially to produce vinyl chloride, and here we show that this facile synthesis method can produce effective catalysts for acetylene hydrochlorination in the absence of the highly oxidizing acidic solvents previously used

Infection control and the burden of tuberculosis infection and disease in health care workers in china: a cross-sectional study

<p>Abstract</p> <p>Background</p> <p>Hospitals with inadequate infection control are risky environments for the emergence and transmission of tuberculosis (TB). We evaluated TB infection control practices, and the prevalence of latent TB infection (LTBI) and TB disease and risk factors in health care workers (HCW) in TB centers in Henan province in China.</p> <p>Methods</p> <p>A cross-sectional survey was conducted in 2005. To assess TB infection control practices in TB centers, checklists were used. HCW were tuberculin skin tested (TST) to measure LTBI prevalence, and were asked for sputum smears and chest X-rays to detect TB disease, and questionnaires to assess risk factors. Differences between groups for categorical variables were analyzed by binary logistic regression. The clustered design of the study was taken into account by using a multilevel logistic model.</p> <p>Results</p> <p>The assessment of infection control practices showed that only in a minority of the centers the patient consultation areas and X-ray areas were separated from the waiting areas and administrative areas. Mechanical ventilation was not available in any of the TB centers. N95 respirators were not available for HCW and surgical masks were not available for TB patients and suspects. The LTBI prevalence of HCW with and without BCG scar was 55.6% (432/777) and 49.0% (674/1376), respectively (P = 0.003). Older HCW, HCW with longer duration of employment, and HCW who worked in departments with increased contact with TB patients had a higher prevalence of LTBI. HCW who work in TB centers at the prefecture level, or with an inpatient ward also had a higher prevalence of LTBI. Twenty cases of pulmonary TB were detected among 3746 HCW. The TB prevalence was 6.7/1000 among medical staff and 2.5/1000 among administrative/logistic staff.</p> <p>Conclusion</p> <p>TB infection control in TB centers in Henan, China, appears to be inadequate and the prevalence of LTBI and TB disease among HCW was high. TB infection control practices in TB centers should be strengthened in China, including administrative measures, renovation of buildings, and use of respirators and masks. Regular screening of HCW for TB disease and LTBI needs to be considered, offering preventive therapy to those with TST conversions.</p

Acute Effects of Sex Steroid Hormones on Susceptibility to Cardiac Arrhythmias: A Simulation Study

Acute effects of sex steroid hormones likely contribute to the observation that post-pubescent males have shorter QT intervals than females. However, the specific role for hormones in modulating cardiac electrophysiological parameters and arrhythmia vulnerability is unclear. Here we use a computational modeling approach to incorporate experimentally measured effects of physiological concentrations of testosterone, estrogen and progesterone on cardiac ion channel targets. We then study the hormone effects on ventricular cell and tissue dynamics comprised of Faber-Rudy computational models. The “female” model predicts changes in action potential duration (APD) at different stages of the menstrual cycle that are consistent with clinically observed QT interval fluctuations. The “male” model predicts shortening of APD and QT interval at physiological testosterone concentrations. The model suggests increased susceptibility to drug-induced arrhythmia when estradiol levels are high, while testosterone and progesterone are apparently protective. Simulations predict the effects of sex steroid hormones on clinically observed QT intervals and reveal mechanisms of estrogen-mediated susceptibility to prolongation of QT interval. The simulations also indicate that acute effects of estrogen are not alone sufficient to cause arrhythmia triggers and explain the increased risk of females to Torsades de Pointes. Our results suggest that acute effects of sex steroid hormones on cardiac ion channels are sufficient to account for some aspects of gender specific susceptibility to long-QT linked arrhythmias

Genome Sequencing and Comparative Transcriptomics of the Model Entomopathogenic Fungi Metarhizium anisopliae and M. acridum

Metarhizium spp. are being used as environmentally friendly alternatives to chemical insecticides, as model systems for studying insect-fungus interactions, and as a resource of genes for biotechnology. We present a comparative analysis of the genome sequences of the broad-spectrum insect pathogen Metarhizium anisopliae and the acridid-specific M. acridum. Whole-genome analyses indicate that the genome structures of these two species are highly syntenic and suggest that the genus Metarhizium evolved from plant endophytes or pathogens. Both M. anisopliae and M. acridum have a strikingly larger proportion of genes encoding secreted proteins than other fungi, while ∼30% of these have no functionally characterized homologs, suggesting hitherto unsuspected interactions between fungal pathogens and insects. The analysis of transposase genes provided evidence of repeat-induced point mutations occurring in M. acridum but not in M. anisopliae. With the help of pathogen-host interaction gene database, ∼16% of Metarhizium genes were identified that are similar to experimentally verified genes involved in pathogenicity in other fungi, particularly plant pathogens. However, relative to M. acridum, M. anisopliae has evolved with many expanded gene families of proteases, chitinases, cytochrome P450s, polyketide synthases, and nonribosomal peptide synthetases for cuticle-degradation, detoxification, and toxin biosynthesis that may facilitate its ability to adapt to heterogenous environments. Transcriptional analysis of both fungi during early infection processes provided further insights into the genes and pathways involved in infectivity and specificity. Of particular note, M. acridum transcribed distinct G-protein coupled receptors on cuticles from locusts (the natural hosts) and cockroaches, whereas M. anisopliae transcribed the same receptor on both hosts. This study will facilitate the identification of virulence genes and the development of improved biocontrol strains with customized properties

The Current State of Proteomics in GI Oncology

Proteomics refers to the study of the entire set of proteins in a given cell or tissue. With the extensive development of protein separation, mass spectrometry, and bioinformatics technologies, clinical proteomics has shown its potential as a powerful approach for biomarker discovery, particularly in the area of oncology. More than 130 exploratory studies have defined candidate markers in serum, gastrointestinal (GI) fluids, or cancer tissue. In this article, we introduce the commonly adopted proteomic technologies and describe results of a comprehensive review of studies that have applied these technologies to GI oncology, with a particular emphasis on developments in the last 3 years. We discuss reasons why the more than 130 studies to date have had little discernible clinical impact, and we outline steps that may allow proteomics to realize its promise for early detection of disease, monitoring of disease recurrence, and identification of targets for individualized therapy

Expression of Ghrelin and GHSR-1a in Long Term Diabetic Rat's Kidney

The aim of this work was to study the relative ghrelin and growth hormone secretagogue receptor (GHS-R)1a gene expression in the kidney of long-term diabetic rats. Forty male Wistar albino rats were divided into four groups: C- control group, DI- one month diabetic rats group, DII- two months diabetic rats group, and DIII- three months diabetic rats group. Diabetes was induced by streptozotocin STZ (40mg/kg i.p). The rats were decapitated under ketamine anesthesia and their kidney tissues were removed. Tissue GHS-R mRNA levels, ghrelin expression, and histopathological damage scores were compared. Dilatation in the distal tubules, epithelial desquamation into the lumen of the tubules and transparent tubules showing glycogen vacuolation were observed in all the diabetic groups. Ghrelin immunoreactivity was significantly higher in group DI compared to group C, whereas in groups DII and DIII, ghrelin immunoreactivity was similar with group C. GHSR-1a mRNA level in group DIII was significantly lower than in group C. As a result, ghrelin immunoreactivity increased at the beginning of diabetes; however, with increase in the duration of diabetes ghrelin immunoreactivity approached to the control values. The expression of GHSR-1a mRNA decreased with increase in diabetes duration. It seemed that down-regulation of GHSR-1a contributed to the renal damage induced by long-term diabetes

Li1.5La1.5MO6 (M = W6+, Te6+) as a new series of lithium-rich double perovskites for all-solid-state lithium-ion batteries

Solid-state batteries are a proposed route to safely achieving high energy densities, yet this architecture faces challenges arising from interfacial issues between the electrode and solid electrolyte. Here we develop a novel family of double perovskites, Li1.5La1.5MO6 (M = W6+, Te6+), where an uncommon lithium-ion distribution enables macroscopic ion diffusion and tailored design of the composition allows us to switch functionality to either a negative electrode or a solid electrolyte. Introduction of tungsten allows reversible lithium-ion intercalation below 1 V, enabling application as an anode (initial specific capacity >200 mAh g-1 with remarkably low volume change of ∼0.2%). By contrast, substitution of tungsten with tellurium induces redox stability, directing the functionality of the perovskite towards a solid-state electrolyte with electrochemical stability up to 5 V and a low activation energy barrier (<0.2 eV) for microscopic lithium-ion diffusion. Characterisation across multiple length- and time-scales allows interrogation of the structure-property relationships in these materials and preliminary examination of a solid-state cell employing both compositions suggests lattice-matching avenues show promise for all-solid-state batteries