2,371 research outputs found

    Dirac Equation at Finite Temperature

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    In this paper, we propose finite temperature Dirac equation, which can describe the quantum systems in an arbitrary temperature for a relativistic particle of spin-1/2. When the temperature T=0, it become Dirac equation. With the equation, we can study the relativistic quantum systems in an arbitrary temperature.Comment: arXiv admin note: text overlap with arXiv:1005.2751, arXiv:hep-ph/0004125, arXiv:hep-ph/0005272 by other author

    Chemotactic response and adaptation dynamics in Escherichia coli

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    Adaptation of the chemotaxis sensory pathway of the bacterium Escherichia coli is integral for detecting chemicals over a wide range of background concentrations, ultimately allowing cells to swim towards sources of attractant and away from repellents. Its biochemical mechanism based on methylation and demethylation of chemoreceptors has long been known. Despite the importance of adaptation for cell memory and behavior, the dynamics of adaptation are difficult to reconcile with current models of precise adaptation. Here, we follow time courses of signaling in response to concentration step changes of attractant using in vivo fluorescence resonance energy transfer measurements. Specifically, we use a condensed representation of adaptation time courses for efficient evaluation of different adaptation models. To quantitatively explain the data, we finally develop a dynamic model for signaling and adaptation based on the attractant flow in the experiment, signaling by cooperative receptor complexes, and multiple layers of feedback regulation for adaptation. We experimentally confirm the predicted effects of changing the enzyme-expression level and bypassing the negative feedback for demethylation. Our data analysis suggests significant imprecision in adaptation for large additions. Furthermore, our model predicts highly regulated, ultrafast adaptation in response to removal of attractant, which may be useful for fast reorientation of the cell and noise reduction in adaptation.Comment: accepted for publication in PLoS Computational Biology; manuscript (19 pages, 5 figures) and supplementary information; added additional clarification on alternative adaptation models in supplementary informatio

    Schr\"odinger equation of general potential

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    It is well known that the Schr\"odinger equation is only suitable for the particle in common potential V(r,t)V(\vec{r},t). In this paper, a general Quantum Mechanics is proposed, where the Lagrangian is the general form. The new quantum wave equation can describe the particle which is in general potential V(r,r˙,t)V(\vec{r}, \dot{\vec{r}}, t). We think these new quantum wave equations can be applied in many fields.Comment: 10 pages, 0 figures, accepted for publication in International Journal of Modern Physics B. arXiv admin note: substantial text overlap with arXiv:0909.2995; and text overlap with arXiv:0711.3544 by other authors without attributio

    The All-Data-Based Evolutionary Hypothesis of Ciliated Protists with a Revised Classification of the Phylum Ciliophora (Eukaryota, Alveolata)

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    This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ The file attached is the published version of the article

    Ambipolar Field Effect in Topological Insulator Nanoplates of (BixSb1-x)2Te3

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    Topological insulators represent a new state of quantum matter attractive to both fundamental physics and technological applications such as spintronics and quantum information processing. In a topological insulator, the bulk energy gap is traversed by spin-momentum locked surface states forming an odd number of surface bands that possesses unique electronic properties. However, transport measurements have often been dominated by residual bulk carriers from crystal defects or environmental doping which mask the topological surface contribution. Here we demonstrate (BixSb1-x)2Te3 as a tunable topological insulator system to manipulate bulk conductivity by varying the Bi/Sb composition ratio. (BixSb1-x)2Te3 ternary compounds are confirmed as topological insulators for the entire composition range by angle resolved photoemission spectroscopy (ARPES) measurements and ab initio calculations. Additionally, we observe a clear ambipolar gating effect similar to that observed in graphene using nanoplates of (BixSb1-x)2Te3 in field-effect-transistor (FET) devices. The manipulation of carrier type and concentration in topological insulator nanostructures demonstrated in this study paves the way for implementation of topological insulators in nanoelectronics and spintronics.Comment: 7 pages, 4 figure

    A study on quantum mechanical approach for C60C_{60} diffraction analysis

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    Diffraction phenomena of large molecules have been studied in many experiments, and these experiments are described by many theoretical works. In this paper, we study C60C_{60} molecules single and double-slit diffraction with quantum theory approach, and we pay close attention to the C60C_{60} diffraction experiment carried out by A.Zeilinger et.at in 1999. In double-slit diffraction, we consider the decoherence effect, and find the theoretical results are good agreement with experimental data.Comment: arXiv admin note: substantial text overlap with arXiv:0910.302

    Efficacy, Safety, and Immunogenicity of an Escherichia coliProduced Bivalent Human Papillomavirus Vaccine: An Interim Analysis of a Randomized Clinical Trial

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    HPV是一种常见的生殖道感染病毒,高危型HPV持续性感染能够导致几乎所有的宫颈癌,其中HPV 16型和18型危害最大,可导致约70%的宫颈癌。预防性HPV疫苗有望减少甚至最终消灭由疫苗型别导致的宫颈癌,降低HPV相关的疾病负担。该研究是在全国4个中心5个现场的18-45岁健康女性中进行的多中心、随机、双盲、对照(戊肝疫苗)的三期临床试验,该研究结果证实我校自主研发的双价人乳头瘤病毒疫苗(大肠杆菌)具有良好的安全性、免疫原性和免疫持久性,可有效地预防HPV 16型和/或18型相关的宫颈高度癌前病变及持续性感染。 该论文报告了我校和厦门万泰沧海生物技术有限公司自主研发的双价人乳头瘤病毒疫苗(大肠杆菌)三期临床试验的期中分析结果。这是第一个进入临床试验并提交药品注册申请的国产人乳头瘤病毒疫苗(HPV疫苗),有望成为世界上第四个上市的HPV疫苗,受到世界卫生组织和盖茨基金会等国际组织的高度关注。 中国医学科学院肿瘤医院乔友林教授、我校吴婷教授、广西壮族自治区疾病预防控制中心李荣成主任医师、江苏省疾病预防控制中心胡月梅主任医师、北京大学人民医院魏丽惠教授、中国食品药品检定研究院李长贵研究员、中国医学科学院肿瘤医院陈汶教授为该论文的共同第一作者,我校张军教授、夏宁邵教授和中国医学科学院肿瘤医院乔友林教授为该论文的共同通讯作者。【Abstract】Background The high cost and insufficient supply of human papillomavirus (HPV) vaccines have slowed the pace of controlling cervical cancer. A phase 3 clinical trial was conducted to evaluate the efficacy, safety and immunogenicity of a novel Escherichia coli-produced bivalent HPV-16/18 vaccine. Methods A multi-centre, randomized, double-blind trial started on November 22, 2012, in China. In total, 7372 eligible women aged 18-45 years were age-stratified and randomly assigned to receiving 3 doses of the test or control (hepatitis E) vaccine at months 0, 1 and 6. Co-primary endpoints included high-grade genital lesions and persistent infection (over 6 months) associated with HPV-16/18. The primary analysis was performed on a per-protocol susceptible population of individuals who were negative for relevant HPV type-specific neutralizing antibodies (at day 0) and DNA (at day 0 through month 7) and who received 3 doses of the vaccine. This report presents data from a pre-specified interim analysis used for regulatory submission. Results In the per-protocol cohort, the efficacies against high-grade genital lesions and persistent infection were 100.0% (95% confidence interval [CI] = 55.6% to 100.0%, 0/3306 in the vaccine group vs. 10/3296 in the control group) and 97.8% (95% CI = 87.1% to 99.9%, 1/3240 vs. 45/3246), respectively. The side effects were mild. No vaccine-related serious adverse events were noted. Robust antibody responses for both types were induced and persisted for at least 42 months. Conclusions The Escherichia coli-produced HPV-16/18 vaccine is well tolerated and highly efficacious against HPV-16/18 associated high-grade genital lesions and persistent infection in women.This work was supported by grants from the Chinese National High-tech R&D Program (863 program, 2012AA02A408), the Chinese National Major Scientific and Technological Special Project for “Significant New Drug Development” (2018ZX09308010 and 2012ZX09101316), the National Natural Science Foundation of China (81673240 and U1705283), the Fujian Provincial Major Scientific and Technological Project (2015YZ0002), the Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences (CIFMS, 2017-I2M-B&R-03, and 2016-I2M-1-019) and Xiamen Innovax. 该研究获得了国家高技术研究发展计划(863计划)、新药创制国家科技重大专项、国家自然科学基金、福建省科技重大专项、中国医学科学院医学与健康科技创新工程基金以及厦门万泰沧海生物技术有限公司的资助

    An Updated Search of Steady TeV γ\gamma-Ray Point Sources in Northern Hemisphere Using the Tibet Air Shower Array

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    Using the data taken from Tibet II High Density (HD) Array (1997 February-1999 September) and Tibet-III array (1999 November-2005 November), our previous northern sky survey for TeV γ\gamma-ray point sources has now been updated by a factor of 2.8 improved statistics. From 0.00.0^{\circ} to 60.060.0^{\circ} in declination (Dec) range, no new TeV γ\gamma-ray point sources with sufficiently high significance were identified while the well-known Crab Nebula and Mrk421 remain to be the brightest TeV γ\gamma-ray sources within the field of view of the Tibet air shower array. Based on the currently available data and at the 90% confidence level (C.L.), the flux upper limits for different power law index assumption are re-derived, which are approximately improved by 1.7 times as compared with our previous reported limits.Comment: This paper has been accepted by hepn
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