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Search Results: 1 - 10 of 119596 matches for " Hong-Lei Liu "
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Altered Nucleotide-Microtubule Coupling and Increased Mechanical Output by a Kinesin Mutant
Hong-Lei Liu, Mark A. Hallen, Sharyn A. Endow
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0047148
Abstract: Kinesin motors hydrolyze ATP to produce force and do work in the cell – how the motors do this is not fully understood, but is thought to depend on the coupling of ATP hydrolysis to microtubule binding by the motor. Transmittal of conformational changes from the microtubule- to the nucleotide-binding site has been proposed to involve the central β-sheet, which could undergo large structural changes important for force production. We show here that mutation of an invariant residue in loop L7 of the central β-sheet of the Drosophila kinesin-14 Ncd motor alters both nucleotide and microtubule binding, although the mutated residue is not present in either site. Mutants show weak-ADP/tight-microtubule binding, instead of tight-ADP/weak-microtubule binding like wild type – they hydrolyze ATP faster than wild type, move faster in motility assays, and assemble long spindles with greatly elongated poles, which are also produced by simulations of assembly with tighter microtubule binding and faster sliding. The mutated residue acts like a mechanochemical coupling element – it transmits changes between the microtubule-binding and active sites, and can switch the state of the motor, increasing mechanical output by the motor. One possibility, based on our findings, is that movements by the residue and the loop that contains it could bend or distort the central β-sheet, mediating free energy changes that lead to force production.
Heavy Metals Pollution Status and Its Stability Assessment in Surface Sediments of Urban Lake-- A Case Study of Moshui Lake in Wuhan

LIU Hong-lei,YIN Cheng-qing,

生态毒理学报 , 2007,
Abstract: Trace heavy metals can cause direct or indirect damages to aquatic ecosystem and human health. To evaluate the heavy metal pollution status of urban lakes, the concentrations and distribution of five trace metals Cr, Cu, Ni, Pb and Zn were detected in the surface sediments of Moshui Lake located in Wuhan City, and the pollution extent and stability were analysed. High pollution extent of heavy metal was found for the surface sediments in this urban lake. All these 5 trace metals'contents exceeded the least effect level(LEL)at all the sampling sites, with most of them exceeding the severe effect level(SEL). A distinct spatial heterogeneity was found in these heavy metals distribution, and the Stability Assessment Code(SAC)was in the order of Zn
Universal construction of order parameters for translation-invariant quantum lattice systems with symmetry-breaking order
Jin-Hua Liu,Qian-Qian Shi,Hong-Lei Wang,Jon Links,Huan-Qiang Zhou
Physics , 2009,
Abstract: For any translation-invariant quantum lattice system with a symmetry group G, we propose a practical and universal construction of order parameters which identify quantum phase transitions with symmetry-breaking order. They are defined in terms of the fidelity between a ground state and its symmetry-transformed counterpart, and are computed through tensor network representations of the ground-state wavefunction. To illustrate our scheme, we consider three quantum systems on an infinite lattice in one spatial dimension, namely, the quantum Ising model in a transverse magnetic field, the quantum spin-1/2 XYX model in an external magnetic field, and the quantum spin-1 XXZ model with single-ion anisotropy. All these models have symmetry group Z_2 and exhibit broken-symmetry phases. We also discuss the role of the order parameters in identifying factorized states.
Huan-Huan BAO,Qing-Jian LIANG,Hong-Lei ZHU,Xiao-Qiu ZHOU,Wei-Hong ZHENG,Jin-Song LIU
动物学研究 , 2014, DOI: 10.13918/j.issn.2095-8137.2014.4.280
Abstract: Tobetterunderstandthephysiologicalcharacteristicsofthesilkystarling(Sturnussericeus),itsbodytemperature(Tb),basalmetabolicrate(BMR),evaporativewaterloss(EWL)andthermalconductance(C)elicitedbydifferentambienttemperatures(Ta)(5-30℃)weredeterminedinthepresentstudy.OurresultsshowedthattheyhaveahighTb(41.6±0.1℃),awidethermalneutralzone(TNZ)(20-27.5℃)andarelativelylowBMRwithintheTNZ(3.37±0.17mLO2/g·h).TheEWLwasnearlystablebelowtheTNZ(0.91±0.07mgH2O/g·h)butincreasedremarkablywithinandabovetheTNZ.TheCwasconstantbelowtheTNZ,withaminimumvalueof0.14±0.01mLO2/g·h·℃.ThesefindingsindicatethattheBMR,TbandEWLofthesilkystarlingwereallaffectedbyTa,especiallywhenTawasbelow20℃andtheEWLplaysanimportantroleinthermalregulation.
Characteristic parameters of electromagnetic signals from a human heart system

Liu Xin-Yuan,Pei Liu-Qing,Wang Yin,Zhang Su-Ming,Gao Hong-Lei,Dai Yuan-Dong,

中国物理 B , 2011,
Abstract: The electromagnetic field of a human heart system is a bioelectromagnetic field. Electrocardiography (ECG) and magnetocardiography (MCG) are both carriers of electromagnetic information about the cardiac system, and they are nonstationary signals. In this study, ECG and MCG data from healthy subjects are acquired; the MCG data are captured using a high-Tc radio frequency superconducting quantum interference device (HTc rf SQUIDs) and the QRS complexes in these data are analysed by the evolutionary spectrum analysis method. The results show that the quality factor Q and the central frequency fz of the QRS complex evolutionary spectrum are the characteristic parameters (CHPs) of ECG and MCG in the time-frequency domain. The confidence intervals of the mean values of the CHPs are estimated by the Student t distribution method in mathematical statistics. We believe that there are threshold ranges of the mean values of Q and fz for healthy subjects. We have postulated the following criterion: if the mean values of CHPs are in the proper ranges, the cardiac system is in a normal condition and it possesses the capability of homeostasis. In contrast, if the mean values of the CHPs do not lie in the proper ranges, the homeostasis of the cardiac system is lacking and some cardiac disease may follow. The results and procedure of MCG CHPs in the study afford a technological route for the application of HTc rf SQUIDs in cardiology.
Induction of lung lesions in Wistar rats by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and its inhibition by aspirin and phenethyl isothiocyanate
Bo Ye, Yu-Xia Zhang, Fei Yang, Hong-Lei Chen, Dong Xia, Ming-Qiu Liu, Bai-Tang Lai
BMC Cancer , 2007, DOI: 10.1186/1471-2407-7-90
Abstract: First, rats were treated with a single-dose of NNK by intratracheal instillation; control rats received iodized oil. The animals were then sacrificed on the indicated day after drug administration and examined for tumors in the target organs. PCNA, p63 and COX-2 expression were analyzed in the preneoplastic lung lesions. Second, rats were treated with a single-dose of NNK (25 mg/kg body weight) in the absence or presence of aspirin and/or PEITC in the daily diet. The control group received only the vehicle in the regular diet. The animals were sacrificed on day 91 after bronchial instillation of NNK. Lungs were collected and processed for histopathological and immunohistochemical assays.NNK induced preneoplastic lesions in lungs, including 33.3% alveolar hyperplasia and 55.6% alveolar atypical dysplasia. COX-2 expression increased similarly in alveolar hyperplasia and alveolar atypical dysplasia, while PCNA expression increased more significantly in the latter than the former. No p63 expression was detected in the preneoplastic lesions. In the second study, the incidences of alveolar atypical dysplasia were reduced to 10%, 10% and 0%, respectively, in the aspirin, PEITC and aspirin and PEITC groups, compared with 62.5% in the carcinogen-treated control group. COX-2 expression decreased after dietary aspirin or aspirin and PEITC treatment. PCNA expression was significantly reduced in the aspirin and PEITC group.(1) A single dose of 25 mg/kg body weight NNK by intratracheal instillation is sufficient to induce preneoplastic lesions in Wistar rat lungs. (2) COX-2 takes part in NNK-induced tumorigenesis but is not involved in proliferation. (3) Aspirin and PEITC have protective effects in the early stages of tumor progression initiated by NNK.Lung cancer is strongly associated with cigarette smoking [1]. It is the single best-documented risk factor for all lung cancer types [2]. Each cigarette contains a mixture of carcinogens, including the tobacco-specific nitrosamine
Metals in Sediments of an Urban Lake in China as Archives of Anthropogenic Activities-A Case Study of Moshui Lake in Wuhan

LIU Hong-lei,LI Li-qing,YIN Cheng-qing,

生态毒理学报 , 2007,
Abstract: 人类活动使得大量的重金属向水环境中排放,导致了城市湖泊严重的重金属污染.为了研究中国的工业化、城市化发展对城市水体重金属污染的影响,以武汉墨水湖为例,测定了沉积物中几种常见痕量重金属Zn、Pb、Ni、Cu、Cr的含量和富集系数,并运用主成分分析对重金属的污染来源进行了初步探讨.结果表明,墨水湖表层沉积物重金属污染程度较重,主要受人为输入的影响;5种重金属在全湖区域上具有比较高的富集系数,尤以排污口为甚,排污口是重金属富集的主要区域.主成分分析表明,Pb可能主要来自于暴雨径流面源,而Cr可能主要来自于工矿企业的点源排放,其他3种金属则有着大小相当的点、面源输入贡献.以上结果表明,城市化和工业化进程已经给城市湖泊带来了很高的重金属污染负荷.
Research on Software Architecture Evaluation Methods

HU Hong-lei,WU Guo-qing,LIANG Zheng-ping,LIU Qiu-hua,

计算机应用研究 , 2004,
Abstract: The architecture evaluation of a software system has become more and more important to guarantee the final quality of the system.The purpose of evaluation is to identify the potential risks of the architecture and to verify the quality requirements addressed in the design.This paper presents three mature evaluation methods (SAAM,ATAM,ALPSM) firstly,then compare them in a conceptive framework to find the similarities and differences between these three methods.In the last discusses the combination of multiple methods,the reuse in evaluating the architecture,the introduction of evaluation to design and use in practice.

LIU Xiao-Lei,SHAN Hong-Xian,JIA Yong-Gang,LI Hong-Lei,ZHENG Jie-Wen,

海洋与湖沼 , 2012,
Abstract: In order to study the correlations between resistivity and mechanical properties of the seabed sediments during the consolidation process in the Yellow River estuary, and to explore a new in-situ monitoring technique for the process, a series of experiments were conducted on the tidal flat of Diaokou delta-lobe that lies in the north of the Yellow River Delta. The fluid sediments imitating the rapidly depositing seabed silts were taken in situ, and the fluid sediments were promptly filled into a one-meter deep pit excavated on the tidal flat. Using field-testing methods, including static cone penetration test, field vaneshear test and pore water piezometer test, variations in mechanical strength and dissipation of pore water pressure were measured in real time. A homemade monitoring probe with ring electrodes was alsoburied in the sediments to measure the real-time resistiv-ity during the sediment consolidation process. Based on the experimental data, good power correlations were found between re-sistivity and penetration strength, specific penetration resistance and undrained shear strength (includingpeak strength and re-sidual shear strength) of the saturated silty soil in the Yellow River ESTUARINE area. There was a negative linear correlation between resistivity and pore water pressure. We propose that resistivity method can be used as an effective way to obtain the degree of consolidation of the silty soil in the Yellow River estuarine area.
Preliminary Studies on Protozoans Community Diversity in the Water Area of the Sun Island in Harbin

HAN Lei,SHI Xin-Lu,LIU Gui-Jie,TAN Xiao-Li,HAN Hong-Lei,

水生生物学报 , 2007,
Abstract: 近年来,随着科学技术的发展与进步,环境污染问题逐渐引起全人类的密切关注。水体污染作为环境污染的一部分,已经成为许多国家和社会亟待解决的一个重大问题。原生动物是水生态系中的重要组成部分,它们作为捕食者(或初级消费者)和被捕食者在水体物质循环和能量流动过程中发挥着十分重要的作用。
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