Arc Erosion Behaviors of Ag-GNPs Electrical Contact Materials Fabricated with Different Graphene Nanoplates Content

In order to clarify the arc erosion behavior of Ag-GNPs electrical contact materials, Ag-GNPs electrical contact materials with different graphene nanoplates content from 0.5wt.% to 2.0wt.% were prepared by powder metallurgy. The microstructure, density, and electrical conductivity were investigated in detail. The weight loss, surface morphologies of the Ag-GNPs materials after arc erosion were characterized, and the arc erosion mechanism of Ag-GNPs materials was discussed. The experimental results show that high GNPs content decreases the densities and electrical conductivity of the Ag-GNPs materials. The Ag-GNPs electrical contact material with 1.5wt.%GNPs presents the best anti-arc erosion performance, which has the lowest weight loss and shallowest arc erosion pits after arc erosion under DC 25V/15A

Astragalus polysaccharide relieves reproductive toxicity in phenobarbital-treated epileptic rats

Purpose: To investigate the underlying mechanisms by which Astragalus  polysaccharide (APS) relieves the reproductive toxicity induced by phenobarbital (PB) treatment in epileptic rats.Methods: Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay kits were used to quantify cell apoptosis in an epileptic rat model. The weight of sex organs and levels of three reproductive hormones, viz, follicle stimulating hormone (FSH), luteinizing hormone (LH) and testosterone, were measured in order to evaluate the effect of APS administration on reproductive ability. Concentration, motility, morphology as well as fertilization rate of sperms were analyzed as well.Results: Increase in sex organ weight and decrease in apoptosis were both  associated with oral APS treatment. In APS-treated group, FSH, LH, and  testosterone levels were raised while concentration, motility and normal morphology of sperm also increased. This was consistent with the observed increase in fertilization rate. In addition, hematoxylin and eosin (HE) staining of the testis was performed in the epileptic rat model showed that the size of cell lumen increased in APS-treated group. All APSassociated phenotypes occurred in a concentration-dependent manner.Conclusion: These data suggest that APS lowers reproductive toxicity in PB-treated epileptic rats by regulating the reproductive hormones, FSH, LH and testosterone, and also by altering the concentration, motility, and morphology of sperm. Thus, APS has a potential treatment for minimizing the side effects of antiepileptic drugs.Keywords: Astragalus polysaccharide, Reproductive toxicity, Phenobarbital,  Epileptic rat

Using Dempster-Shafer’s evidence theory for query expansion based on freebase knowledge

Query expansion is generally a useful technique in improving search performance. However, some expanded query terms obtained by traditional statistical methods (e.g., pseudo-relevance feedback) may not be relevant to the user's information need, while some relevant terms may not be contained in the feedback documents at all. Recent studies utilize external resources to detect terms that are related to the query, and then adopt these terms in query expansion. In this paper, we present a study in the use of Freebase, which is an open source general-purpose ontology, as a source for deriving expansion terms. FreeBase provides a graph-based model of human knowledge, from which a rich and multi-step structure of instances related to the query concept can be extracted, as a complement to the traditional statistical approaches to query expansion. We propose a novel method, based on the well-principled Dempster-Shafer's (D-S) evidence theory, to measure the certainty of expansion terms from the Freebase structure. The expanded query model is then combined with a state of the art statistical query expansion model - the Relevance Model (RM3). Experiments show that the proposed method achieves significant improvements over RM3

Turbulent heat flux reconstruction in the north Pacific from 1921 to 2014

Turbulent heat flux is the main passageway for air–sea interactions. However, owing to a lack of long-term observations of turbulent heat flux, it is difficult to investigate the mechanisms of coupled ocean–atmosphere variabilities, such as the Pacific Decadal Oscillation. In this study, we reconstructed the long-term turbulent heat flux in the North Pacific from 1921 to 2014 on the basis of observations in the International Comprehensive Ocean-Atmosphere Data Set–International Maritime Meteorological Archive. Sea surface temperature, air temperature, wind, and humidity were used to reconstruct the turbulent heat flux by using the Coupled Ocean– Atmosphere Response Experiment 3.5 algorithm. The modified Fisher–Tippett distribution was employed to calculate the turbulent heat flux at each grid square, and missing values were further derived on the basis of data interpolating empirical orthogonal functions. The reconstructed turbulent heat flux was shown to be in accordance with the commonly used short-term heat flux datasets. This reconstruction is further examined by comparing it with long-term data from the European Center for Medium-Range Weather Forecasts twentieth-century reanalysis (ERA-20C) and the Twentieth Century Reanalysis (20CR) dataset from the National Oceanic and Atmospheric Administration. This reconstruction displays good agreement with ERA-20C both in spatial and temporal scales but shows some differences from 20CR. These examinations show that the reconstructed turbulent heat flux can reproduce well the main features of air–sea interaction in the North Pacific, which can be used in the studies of air–sea interaction in the North Pacific on multidecadal timescales. © The Author(s) 2019

The site conditions of the Guo Shou Jing Telescope

The weather at Xinglong Observing Station, where the Guo Shou Jing Telescope (GSJT) is located, is strongly affected by the monsoon climate in north-east China. The LAMOST survey strategy is constrained by these weather patterns. In this paper, we present a statistics on observing hours from 2004 to 2007, and the sky brightness, seeing, and sky transparency from 1995 to 2011 at the site. We investigate effects of the site conditions on the survey plan. Operable hours each month shows strong correlation with season: on average there are 8 operable hours per night available in December, but only 1-2 hours in July and August. The seeing and the sky transparency also vary with seasons. Although the seeing is worse in windy winters, and the atmospheric extinction is worse in the spring and summer, the site is adequate for the proposed scientific program of LAMOST survey. With a Monte Carlo simulation using historical data on the site condition, we find that the available observation hours constrain the survey footprint from 22h to 16h in right ascension; the sky brightness allows LAMOST to obtain the limit magnitude of V = 19.5mag with S/N = 10.Comment: 10 pages, 8 figures, accepted for publication in RA

Fluorescent nanoparticles for sensing

Nanoparticle-based fluorescent sensors have emerged as a competitive alternative to small molecule sensors, due to their excellent fluorescence-based sensing capabilities. The tailorability of design, architecture, and photophysical properties has attracted the attention of many research groups, resulting in numerous reports related to novel nanosensors applied in sensing a vast variety of biological analytes. Although semiconducting quantum dots have been the best-known representative of fluorescent nanoparticles for a long time, the increasing popularity of new classes of organic nanoparticle-based sensors, such as carbon dots and polymeric nanoparticles, is due to their biocompatibility, ease of synthesis, and biofunctionalization capabilities. For instance, fluorescent gold and silver nanoclusters have emerged as a less cytotoxic replacement for semiconducting quantum dot sensors. This chapter provides an overview of recent developments in nanoparticle-based sensors for chemical and biological sensing and includes a discussion on unique properties of nanoparticles of different composition, along with their basic mechanism of fluorescence, route of synthesis, and their advantages and limitations

Current trends in drug metabolism and pharmacokinetics.

Pharmacokinetics (PK) is the study of the absorption, distribution, metabolism, and excretion (ADME) processes of a drug. Understanding PK properties is essential for drug development and precision medication. In this review we provided an overview of recent research on PK with focus on the following aspects: (1) an update on drug-metabolizing enzymes and transporters in the determination of PK, as well as advances in xenobiotic receptors and noncoding RNAs (ncRNAs) in the modulation of PK, providing new understanding of the transcriptional and posttranscriptional regulatory mechanisms that result in inter-individual variations in pharmacotherapy; (2) current status and trends in assessing drug-drug interactions, especially interactions between drugs and herbs, between drugs and therapeutic biologics, and microbiota-mediated interactions; (3) advances in understanding the effects of diseases on PK, particularly changes in metabolizing enzymes and transporters with disease progression; (4) trends in mathematical modeling including physiologically-based PK modeling and novel animal models such as CRISPR/Cas9-based animal models for DMPK studies; (5) emerging non-classical xenobiotic metabolic pathways and the involvement of novel metabolic enzymes, especially non-P450s. Existing challenges and perspectives on future directions are discussed, and may stimulate the development of new research models, technologies, and strategies towards the development of better drugs and improved clinical practice