362 research outputs found

    INFLUENCE OF RARE-EARTH DOPING ON THE ELECTRICAL PROPERTIES OF HIGH VOLTAGE GRADIENT ZnO VARISTORS

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    The influence of rare-earth doping on the electrical properties of ZnO varistors was investigated. In a lower doping region, the electrical properties were greatly improved with the increase of rare-earth contents. The highest voltage gradient value of 1968.0 V/mm was obtained with a rare-earth concentration of 0.06 mol. %. The microstructure of samples with different amounts of rare-earth oxides was examined and the notable decrease of grain size was identified as the origin for the increased voltage gradient. The doped rare-earth oxides dissolved at the grain boundaries and the excessive doping reduced the voltage across the single grain/grain boundary from 2.72 V to 0.91 V. The poor electrical properties in a higher doping region resulted from the degeneration of grain boundaries and the decrease of block density

    BOIN: An R Package for Designing Single-Agent and Drug-Combination Dose-Finding Trials Using Bayesian Optimal Interval Designs

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    This article describes the R package BOIN, which implements a recently developed methodology for designing single-agent and drug-combination dose-finding clinical trials using Bayesian optimal interval designs (Liu and Yuan 2015; Yuan, Hess, Hilsenbeck, and Gilbert 2016). The BOIN designs are novel "model-assisted" phase I trial designs that can be implemented simply and transparently, similar to the 3 + 3 design, but yield excellent performance comparable to those of more complicated, model-based designs. The BOIN package provides tools for designing, conducting, and analyzing single-agent and drug-combination dose-finding trials

    Transmission of H7N9 influenza virus in mice by different infective routes.

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    BackgroundOn 19 February 2013, the first patient infected with a novel influenza A H7N9 virus from an avian source showed symptoms of sickness. More than 349 laboratory-confirmed cases and 109 deaths have been reported in mainland China since then. Laboratory-confirmed, human-to-human H7N9 virus transmission has not been documented between individuals having close contact; however, this transmission route could not be excluded for three families. To control the spread of the avian influenza H7N9 virus, we must better understand its pathogenesis, transmissibility, and transmission routes in mammals. Studies have shown that this particular virus is transmitted by aerosols among ferrets.MethodsTo study potential transmission routes in animals with direct or close contact to other animals, we investigated these factors in a murine model.ResultsViable H7N9 avian influenza virus was detected in the upper and lower respiratory tracts, intestine, and brain of model mice. The virus was transmissible between mice in close contact, with a higher concentration of virus found in pharyngeal and ocular secretions, and feces. All these biological materials were contagious for naΓ―ve mice.ConclusionsOur results suggest that the possible transmission routes for the H7N9 influenza virus were through mucosal secretions and feces

    Genetic Variants on Chromosome 8q24 and Colorectal Neoplasia Risk: A Case-Control Study in China and a Meta-Analysis of the Published Literature

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    Previous studies have found that common genetic variants on chromosome 8q24 are associated with the risk of developing colorectal neoplasia. We conducted a hospital-based case-control study, including 435 cases and 788 unrelated controls to investigate the associations between common variants on 8q24 and the risk of colorectal cancer in a Chinese population. We also evaluated the association of rs6983267 with colorectal neoplasia in the published literature via a meta-analysis study. We found that rs6983267 was significantly associated with the risk of colorectal cancer in the Chinese population, with an adjusted odds-ratio (OR) for the GT heterozygotes and GG homozygotes of 1.30 (95% CI β€Š=β€Š0.98–1.71, Pβ€Š=β€Š0.069) and 1.66 (95% CI β€Š=β€Š1.18–2.34, Pβ€Š=β€Š0.004), respectively, compared to the TT homozygotes, with a P-trend value of 0.003. No association was found for the other three loci (rs16901979, rs1447295 and rs7837688). In the meta-analysis of the published genetic association studies, the rs6983267 variant was found to be associated with an increased risk of colorectal neoplasia. The heterozygous GT carriers showed a 20% increased risk of colorectal neoplasia (OR β€Š=β€Š1.20, 95% CI β€Š=β€Š1.16–1.25; random effects model) with a summary OR for homozygous GG carriers of 1.39 (95% CI β€Š=β€Š1.32–1.48; random effects model) compared to the TT genotype carriers. We found no significant differences between the association of rs6983267 and colorectal cancer and colorectal adenomas. In summary, our study confirms that the variant rs6983267 is a risk factor for colorectal neoplasia in various populations, including the Chinese population

    SkyLens: Visual analysis of skyline on multi-dimensional data

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    Skyline queries have wide-ranging applications in fields that involve multi-criteria decision making, including tourism, retail industry, and human resources. By automatically removing incompetent candidates, skyline queries allow users to focus on a subset of superior data items (i.e., the skyline), thus reducing the decision-making overhead. However, users are still required to interpret and compare these superior items manually before making a successful choice. This task is challenging because of two issues. First, people usually have fuzzy, unstable, and inconsistent preferences when presented with multiple candidates. Second, skyline queries do not reveal the reasons for the superiority of certain skyline points in a multi-dimensional space. To address these issues, we propose SkyLens, a visual analytic system aiming at revealing the superiority of skyline points from different perspectives and at different scales to aid users in their decision making. Two scenarios demonstrate the usefulness of SkyLens on two datasets with a dozen of attributes. A qualitative study is also conducted to show that users can efficiently accomplish skyline understanding and comparison tasks with SkyLens.Comment: 10 pages. Accepted for publication at IEEE VIS 2017 (in proceedings of VAST

    Tracking the nematicity in cuprate superconductors: a resistivity study under uniaxial pressure

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    Overshadowing the superconducting dome in hole-doped cuprates, the pseudogap state is still one of the mysteries that no consensus can be achieved. It has been suggested that the rotational symmetry is broken in this state and may result in a nematic phase transition, whose temperature seems to coincide with the onset temperature of the pseudogap state Tβˆ—T^* around optimal doping level, raising the question whether the pseudogap results from the establishment of the nematic order. Here we report results of resistivity measurements under uniaxial pressure on several hole-doped cuprates, where the normalized slope of the elastoresistivity ΞΆ\zeta can be obtained as illustrated in iron-based superconductors. The temperature dependence of ΞΆ\zeta along particular lattice axis exhibits kink feature at TkT_{k} and shows Curie-Weiss-like behavior above it, which may suggest a spontaneous nematic transition. While TkT_{k} seems to be the same as Tβˆ—T^* around the optimal doping and in the overdoped region, they become very different in underdoped La2βˆ’x_{2-x}Srx_{x}CuO4_4. Our results suggest that the nematic order, if indeed existing, is an electronic phase within the pseudogap state.Comment: 6 pages, 4 figure
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