1,332 research outputs found

    High capacity cathode materials for Li-S batteries

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    To enhance the stability of sulfur cathode for a high energy lithium-sulfur battery, sulfur-activated carbon (S-AC) composite was prepared by encapsulating sulfur into micropores of activated carbon using a solution-based processing technique. In the analysis using the prepared specimen of S-AC composite by the focused ion beam (FIB) technique, the elemental sulfur exists in a highly dispersed state inside the micropores of activated carbon, which has a large surface area and a narrow pore distribution. The S-AC composite was characterized through X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) method, selected area electron diffraction (SAED), energy dispersive X-ray spectrometry (EDX), Fourier transform infrared spectroscopy (FT-IR), thermogravimetry analysis (TGA), and field emission scanning electron microscopy (FESEM). A lithium-sulfur cell using the S-AC composite has a high first discharge capacity over 800 mA h g -1 S even at a high current density such as 2C (3200 mA g -1 S) and has good cycleability around 500 mA h g-1 S discharge capacity at the 50th cycle at the same current density. © 2013 The Royal Society of Chemistry

    Nanosheet thickness-modulated MoS2 dielectric property evidenced by field-effect transistor performance

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    We report on the nanosheet-thickness effects on the performance of top-gate MoS2 field-effect transistors (FETs), which is directly related to the MoS2 dielectric constant. Our top-gate nanosheet FETs with 40 nm thin Al2O3 displayed at least an order of magnitude higher mobility than those of bottom-gate nanosheet FETs with 285 nm thick SiO2, benefiting from the dielectric screening by high-k Al2O3. Among the top-gate devices, the single-layered FET demonstrated the highest mobility of similar to 170 cm(2) V-1 s(-1) with 90 mV dec(-1) as the smallest subthreshold swing (SS) but the double-and triple-layered FETs showed only similar to 25 and similar to 15 cm(2) V-1 s(-1) respectively with the large SS of 0.5 and 1.1 V dec(-1). Such property degradation with MoS2 thickness is attributed to its dielectric constant increase, which could rather reduce the benefits from the top-gate high-k dielectric.open115353Nsciescopu

    Proteins identification of wheat-rye translocation lines by MALDI-TOF-TOF mass spectrometry and ESI-QTOF/MS

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    OBJECTIVE: To examine the relationship between Timed Up and Go (TUG) performance, verbal executive function (EF) performance, and quality-of-life (QOL) measures in Parkinson's disease (PD). DESIGN: Cross-sectional. SETTING: Sixteen movement disorder centers from across the United States. PARTICIPANTS: Patients with PD (N=1964). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: TUG test, immediate and delayed 5-word recall, verbal fluency, PD QOL Questionnaire. RESULTS: TUG performance and verbal EF performance were significantly associated with, and predictors of, QOL measures, having the greatest association and predictability with the mobility domain of the QOL measures. CONCLUSIONS: The TUG test and verbal EF tests have QOL correlates, making the combined evaluation of mobility, cognitive, and QOL decline a potential examination tool to evaluate the sequelae of PD

    Locational memory of macrovessel vascular cells is transcriptionally imprinted

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    Vascular pathologies show locational predisposition throughout the body; further insights into the transcriptomics basis of this vascular heterogeneity are needed. We analyzed transcriptomes from cultured endothelial cells and vascular smooth muscle cells from nine adult canine macrovessels: the aorta, coronary artery, vena cava, portal vein, femoral artery, femoral vein, saphenous vein, pulmonary vein, and pulmonary artery. We observed that organ-specific expression patterns persist in vitro, indicating that these genes are not regulated by blood flow or surrounding cell types but are likely fixed in the epigenetic memory. We further demonstrated the preserved location-specific expression of GATA4 protein in cultured cells and in the primary adult vessel. On a functional level, arterial and venous endothelial cells differed in vascular network morphology as the arterial networks maintained a higher complexity. Our findings prompt the rethinking of the extrapolation of results from single-origin endothelial cell systems

    Top-up operation at Pohang Light Source-II

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    After three years of upgrading work, PLS-II (S. Shin, Commissioning of the PLS-II, JINST, January 2013) is now successfully operating. The top-up operation of the 3 GeV linear accelerator had to be delayed because of some challenges encountered, and PLS-II was run in decay mode at the beginning in March 2012. The main difficulties encountered in the top-up operation of PLS-II are different levels between the linear accelerator and the storage ring, the 14 narrow gap in-vacuum undulators in operation, and the full energy injection by 3 GeV linear accelerator. Large vertical emittance and energy jitter of the linac were the major obstacles that called for careful control of injected beam to reduce beam loss in the storage ring during injection. The following measures were taken to resolve these problems: (1) The high resolution Libera BPM (see http://www.i-tech.si) was implemented to measure the beam trajectory and energy. (2) Three slit systems were installed to filter the beam edge. (3) De-Qing circuit was applied to the modulator system to improve the energy stability of injected beam. As a result, the radiation by beam loss during injection is reduced drastically, and the top-up mode has been successfully operating since 19th March 2013. In this paper, we describe the experimental results of the PLS-II top-up operation and the improvement plan. (C) 2014 AIP Publishing LLC.open111011sciescopu

    Reference Ranges for Bone Mineral Density and Prevalence of Osteoporosis in Vietnamese Men and Women

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    <p>Abstract</p> <p>Background</p> <p>The aim of this study was to examine the effect of different reference ranges in bone mineral density on the diagnosis of osteoporosis.</p> <p>Methods</p> <p>This cross-sectional study involved 357 men and 870 women aged between 18 and 89 years, who were randomly sampled from various districts within Ho Chi Minh City, Vietnam. BMD at the femoral neck, lumbar spine and whole body was measured by DXA (Hologic QDR4500). Polynomial regression models and bootstraps method were used to determine peak BMD and standard deviation (<it>SD</it>). Based on the two parameters, we computed T-scores (denoted by <it>T</it><sub>VN</sub>) for each individual in the study. A similar diagnosis was also done based on T-scores provided by the densitometer (<it>T</it><sub>DXA</sub>), which is based on the US White population (NHANES III). We then compared the concordance between <it>T</it><sub>VN </sub>and <it>T</it><sub>DXA </sub>in the classification of osteoporosis. Osteoporosis was defined according to the World Health Organization criteria.</p> <p>Results</p> <p>In post-menopausal women, the prevalence of osteoporosis based on femoral neck <it>T</it><sub>VN </sub>was 29%, but when the diagnosis was based on <it>T</it><sub>DXA</sub>, the prevalence was 44%. In men aged 50+ years, the <it>T</it><sub>VN</sub>-based prevalence of osteoporosis was 10%, which was lower than <it>T</it><sub>DXA</sub>-based prevalence (30%). Among 177 women who were diagnosed with osteoporosis by <it>T</it><sub>DXA</sub>, 35% were actually osteopenia by <it>T</it><sub>VN</sub>. The kappa-statistic was 0.54 for women and 0.41 for men.</p> <p>Conclusion</p> <p>These data suggest that the <it>T-</it>scores provided by the Hologic QDR4500 over-diagnosed osteoporosis in Vietnamese men and women. This over-diagnosis could lead to over-treatment and influence the decision of recruitment of participants in clinical trials.</p

    Standardising outcome reporting for clinical trials of interventions for heavy menstrual bleeding: Development of a core outcome set

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    OBJECTIVE: To develop a core outcome set for heavy menstrual bleeding (HMB). DESIGN: Core outcome set (COS) development methodology described by the COMET initiative. SETTING: University hospital gynaecology department, online international survey and web-based international consensus meetings. POPULATION OR SAMPLE: Phase 1: Systematic review of previously reported outcomes to identify potential core outcomes. Phase 2: Qualitative studies with patients to identify outcomes most important to them. Phase 3: Online two-round Delphi survey to achieve consensus about which outcomes are most important. Phase 4: A consensus meeting to finalise the COS. METHODS: Phase 1: Systematic review of previously reported outcomes to identify potential core outcomes. Phase 2: Qualitative studies with patients to identify outcomes most important to them. Phase 3: Online two-round Delphi survey to achieve consensus about which outcomes are most important. Phase 4: A consensus meeting to finalise the COS. MAIN OUTCOME MEASURES: Outcome importance was assessed in the Delphi survey on a 9-point scale. RESULTS: From the ‘long list’ of 114, 10 outcomes were included in the final COS: subjective blood loss; flooding; menstrual cycle metrics; severity of dysmenorrhoea; number of days with dysmenorrhoea; quality of life; adverse events; patient satisfaction; number of patients going on to have further treatment for HMB and haemoglobin level. CONCLUSIONS: The final COS includes variables that are feasible for use in clinical trials in all resource settings and apply to all known underlying causes of the symptom of HMB. These outcomes should be reported in all future trials of interventions, their systematic reviews, and clinical guidelines to underpin policy

    Phylogeography of Japanese encephalitis virus:genotype is associated with climate

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    The circulation of vector-borne zoonotic viruses is largely determined by the overlap in the geographical distributions of virus-competent vectors and reservoir hosts. What is less clear are the factors influencing the distribution of virus-specific lineages. Japanese encephalitis virus (JEV) is the most important etiologic agent of epidemic encephalitis worldwide, and is primarily maintained between vertebrate reservoir hosts (avian and swine) and culicine mosquitoes. There are five genotypes of JEV: GI-V. In recent years, GI has displaced GIII as the dominant JEV genotype and GV has re-emerged after almost 60 years of undetected virus circulation. JEV is found throughout most of Asia, extending from maritime Siberia in the north to Australia in the south, and as far as Pakistan to the west and Saipan to the east. Transmission of JEV in temperate zones is epidemic with the majority of cases occurring in summer months, while transmission in tropical zones is endemic and occurs year-round at lower rates. To test the hypothesis that viruses circulating in these two geographical zones are genetically distinct, we applied Bayesian phylogeographic, categorical data analysis and phylogeny-trait association test techniques to the largest JEV dataset compiled to date, representing the envelope (E) gene of 487 isolates collected from 12 countries over 75 years. We demonstrated that GIII and the recently emerged GI-b are temperate genotypes likely maintained year-round in northern latitudes, while GI-a and GII are tropical genotypes likely maintained primarily through mosquito-avian and mosquito-swine transmission cycles. This study represents a new paradigm directly linking viral molecular evolution and climate
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