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Molecular and quantum mechanical studies on the monomer recognition of a highly-regular β-helical antifreeze protein

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science China Chemistry 2004年第1期47卷 34-40页

作者： YAnG Zuoyin, JIA Zongchao, lIU Ruozhuang & CHEn Guangjudepartment of Chemistry, Beijing normal university, Beijing 100875, China Faculty of science, Beijing university of Chemical Technology, Beijing 100029, China department of biochemistry, queen’s university, kingston, ontario k7l 3n6, canada 1. department of Chemistry Beijing Normal University 100875 Beijing China 2. Faculty of science Beijing University of Chemical Technology 100029 Beijing China 3. department of biochemistry Queen? University K7L 3N6 Kingston Ontario Canada

The possible interaction models for an antifreeze protein from Tenebrio molitar (TmAFP) have been systematically studied using the methods of molecular mechanics, molecular dynamics and quantum chemistry. It is hoped that these approaches would provide insights into the nature of interaction between protein monomers through sampling a number of interaction possibilities and evaluating their interaction energies between two monomers in the course of recognition. The results derived from the molecular mechanics indicate that monomer? β-sheets would be involved in interaction area and the side chains on two p-faces can match each other at the two-dimensional level. The results from molecular mechanics and OnIOM methods show that the strongest interaction energy could be gained through the formation of H-bonds when the twoβ-sheets are involved in the interaction model. Furthermore, the calculation of DFT and analysis of van der Waals bond charge density confirm further that recognition between the two TCTs mainly depends on inter-molecular hydroxyls. Therefore, our results demonstrate that during the course of interaction the most favorable association of TmAFPs is via their β-sheets.

关键词： antifreeze protein, recognition, dynamics simulation, molecular mechanics, quantum chemistry.

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Building Crystals from Clusters

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Journal of Materials science & Technology 1999年第4期15卷 299-302页

作者： M.J.stottt(department of Physics, queen’s university, kingston, ontario k7l 3n6, canada)l.M.Molina and J.A.Alonso(Departamento de Fisica Terica, Universidad de Valladolid, E-47011 Valladolid, spain)To whom correspondence should be addressed E-mail: stott@ queens Univ Dept Phys Kingston ON K7L 3N6 Canada Univ Valladolid Dept Fis Teor E-47011 Valladolid Spain

Ab initio total energy calculations are used to simulate the building of equiatomic solid APballoys (A=li, na, k) with A4Pb4 clusters which are particularly stable in the gas phase. Theeight clusters per unit cell were drawn together by shrinking the cell in stages, and allowingfull atomic relaxation at each stage. Charged Pb4 tetrahedral units dominate the structuraland electronic properties, and these units are remarkably robust and insensitive to their alkalienvironment. The stability of the Pb4 units diminishes as we progress from k to li and lead totheir absence in the liPb alloy in accordance with experiment. The distance between Pb4 unitsseems to be the critical factor responsible for the structural trends, which is determined by theatomic size of the alkali.

关键词： Pb Building Crystals from Clusters Rev

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Jackknifed random weighting for Cox proportional hazards model

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science China Mathematics 2012年第4期55卷 775-786页

作者： lI Xiao 1 ,WU YaoHua 2,& TU Dongsheng 1 1 Cancer Research Institute,queen’s university,kingston,ontario k 7l 3n6,canada 2 department of Finance and statistics,university of science and Technology of China,Hefei 230026,China 1. Cancer Research Institute Queen’s University Kingston Ontario K7L 3N6 Canada2. Department of Finance and Statistics University of Science and Technology of China Hefei 230026 China

The Cox proportional hazards model is the most used statistical model in the analysis of survival time ***,a random weighting method was proposed to approximate the distribution of the maximum partial likelihood estimate for the regression coefficient in the Cox *** method was shown not as sensitive to heavy censoring as the bootstrap method in simulation studies but it may not be second-order accurate as was shown for the bootstrap *** this paper,we propose an alternative random weighting method based on one-step linear jackknife pseudo values and prove the second accuracy of the proposed *** Carlo simulations are also performed to evaluate the proposed method for fixed sample sizes.

关键词： Cox proportional hazards model jackknife random weighting second-order accuracy simulations survival data

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Dynamics of a two-group model for assessing the impacts of pre-exposure prophylaxis,testing and risk behaviour change on the spread and control of HIV/AIDs in an MsM population

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Infectious Disease Modelling 2024年第1期9卷 103-127页

作者： queen Tollett salman safdar Abba B.Gumel school of Mathematical and statistical sciences Arizona State UniversityTempeAZ85287USA department of Mathematics University of KarachiUniversity Road75270Pakistan department of Mathematics University of MarylandCollege ParkMD20742USA department of Mathematics and Applied Mathematics University of PretoriaPretoria0002South Africa

Although much progress has been made in reducing the public health burden of the human immunodeficiency virus(HIV),which causes acquired immunodeficiency syndrome(AIDs),since its emergence in the 1980s(largely due to the large-scale use and availability of potent antiviral therapy,improved diagnostic and intervention and mitigation measures),HIV remains an important public health challenge globally,including in the United *** study is based on the use of mathematical modeling approaches to assess the population-level impact of pre-exposure prophylaxis(PrEP),voluntary testing(to detect undetected HIV-infected individuals),and changes in human behavior(with respect to risk structure),on the spread and control of HIV/AIDs in an MsM(men-who-have sex-with-men)***,a novel two-group mathematical model,which stratifies the total MsM population based on risk(low or high)of acquisition of HIV infection,is *** model undergoes a PrEP-induced backward bifurcation when the control reproduction number of the model is less than one if the efficacy of PrEP to prevent a high-risk susceptible MsM individual from acquiring HIV infection is not perfect(the consequence of which is that,while necessary,having the reproduction number of the model less than one is no longer sufficient for the elimination of the disease in the MsM population).For the case where the efficacy of PrEP is perfect,this study shows that the disease-free equilibrium of the two-group model is globally-asymptotically stable when the associated control reproduction number of the model is less than *** sensitivity analysis was carried out to identify the main parameters of the model that have the highest influence on the value of the control reproduction number of the model(thereby,having the highest influence on the disease burden in the MsM population).numerical simulations of the model,using a plausible range of parameter values,show that if half of the MsM population co

关键词： HIV/AIDs Ms MHigh(low)-risk groups PrEP Behavior change Antiviral treatment Control reproduction number

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COnsTRUCTIOn OF COnTInUOUs TIME MARkOVIAn ARRIVAl PROCEssEs

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Journal of systems science and systems Engineering 2010年第3期19卷 351-366页

作者： Qi-Ming HE department of Management sciences,university of Waterloo,Waterloo,ontario,canada n2l 3G1 department of Management sciences University of Waterloo Waterloo Canada

Markovian arrival processes were introduced by neuts in 1979 （neuts 1979） and have been used extensively in the stochastic modeling of queueing, inventory, reliability, risk, and telecommunications systems. In this paper, we introduce a constructive approach to define continuous time Markovian arrival processes. The construction is based on Poisson processes, and is simple and intuitive. such a construction makes it easy to interpret the parameters of Markovian arrival processes. The construction also makes it possible to establish rigorously basic equations, such as kolmogorov differential equations, for Markovian arrival processes, using only elementary properties of exponential distributions and Poisson processes. In addition, the approach can be used to construct continuous time Markov chains with a finite number of states

关键词： Markovian arrival process Poisson process matrix-analytic methods

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Cr-induced fusion reactions to synthesize superheavy elements

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nuclear science and Techniques 2024年第5期35卷 122-130页

作者： s.Madhu H.C.Manjunatha n.sowmya B.M.Rajesh l.seenappa R.s.susheela department of Physics R V College of EngineeringBangalore 560074India Visvesvaraya Technological university BelagaviKarnataka 590018India department of Physics Government First Grade CollegeSrinivasapurKarnataka 563135India department of Physics Government First Grade CollegeDevanahallyKarnataka 562110India department of Physics Government First Grade CollegeMulbagalKarnataka 563131India department of Physics Government First Grade collegeNanjangudOoty RoadMysore 571301India

We investigated ^(50,52-54)Cr-induced fusion reactions for the synthesis of the superheavy element in the 104≤Z≤122 *** cross sections produced in this investigation using ^(54)Cr projectiles were compared with those obtained in prior *** estimated cross sections from this analysis are consistent with the findings of prior *** the current study,the predicted cross section was found to be 42fb at 236 MeV for ^(53)Cr+^(243)Am,23.2 fb at 236 MeV for ^(54)Cr+^(247)Cm,95.6 fb at 240 MeV for ^(53)Cr+248Bk,and 1.33 fb at 242 MeV for ^(53)Cr+***,these projected cross sections with excitation energy and beam energy will be useful in future Cr-induced fusion reaction investigations.

关键词： Fusion cross sections Compound nucleus formation probability survival probability Evaporation residue cross sections

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Empirical model for fusion cross sections of Ca-induced reactions

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Chinese Physics C 2024年第3期48卷 126-132页

作者： Reddi Rani.l n.sowmya k.n sridhar H C.Manjunatha M.M.Armstrong Arasu department of Physics St.Joseph's College(Autonomous)Affiliated to Bharathidasan UniversityTiruchirappalli620002TNIndia department of Physics Govt.First.Grade CollegeChikkaballapur-562101KarnatakaIndia department of Physics Govt.First.Grade CollegeMalur-563160KarnatakaIndia department of Physics Govt.First.Grade CollegeDevanahalli-562110KarnatakaIndia

A new empirical formula for the astrophysical s-factor has been suggested as a function of the Coulomb interaction parameter,center of mass energy,and barrier *** 22 fusion reactions with ^(40,48)Ca as projectiles were considered for different targets,leading to compound nuclei with atomic and mass numbers varying between 40≤Z≤≤Z≤112 and 88≤A≤27888≤A≤278,*** fusion cross-sections have been estimated using the geometric factor,the Gamow-sommerfield factor,and the empirical formula for the *** study's findings showed better agreement with those of available experiments when compared to Wong's *** present work leads to a smaller standard deviation value than Wong's formula when used to correlate the experimental data of calcium-induced fusion ***'s formula provides a good approximation of fusion cross-sections when the center of mass energy is below the fusion barrier when compared to above the fusion barrier.

关键词： fusion cross-sections Wong formula Gamow-sommerfield-factor Geometric-factor s-factor

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Dynamic and electrical responses of a curved sandwich beam with glass reinforced laminate layers and a pliable core in the presence of a piezoelectric layer under low-velocity impact

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Applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 155-178页

作者： n.sHAHVEIsI s.FElI department of Mechanical Engineering Razi UniversityKermanshah ***Iran

The dynamic responses and generated voltage in a curved sandwich beam with glass reinforced laminate(GRl)layers and a pliable core in the presence of a piezoelectric layer under low-velocity impact(lVI)are *** current study aims to carry out a dynamic analysis on the sandwich beam when the impactor hits the top face sheet with an initial *** the layer analysis,the high-order shear deformation theory(HsDT)and Frostig's second model for the displacement fields of the core layer are *** classical non-adhesive elastic contact theory and Hunter's principle are used to calculate the dynamic responses in terms of *** order to validate the analytical method,the outcomes of the current investigation are compared with those gained by the experimental tests carried out by other researchers for a rectangular composite plate subject to the *** element(FE)simulations are conducted by means of the ABAQUs *** effects of the parameters such as foam modulus,layer material,fiber angle,impactor mass,and its velocity on the generated voltage are reviewed.

关键词： analytical model piezoelectric layer curved sandwich beam glass reinforced laminate(GRl) pliable core low-velocity impact(lVI) classical non-adhesive elastic contact theory

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numerical Analysis of the Magnetic Dipole Effect on a Radiative Ferromagnetic liquid Flowing over a Porous stretched sheet

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Fluid Dynamics & Materials Processing 2024年第2期20卷 293-310页

作者： G.Dharmaiah F.Mebarek-Oudina k.s.Balamurugan n.Vedavathi department of Mathematics Narasaraopeta Engineering CollegeNarasaraopetIndia department of Physics Faculty of SciencesUniversity of 20 Août 1955-SkikdaSkikdaAlgeria department of Mathematics RVR&JC College of EngineeringGunturIndia department of Mathematics Koneru Lakshmaiah Education FoundationVaddeswaramIndia

The effects of a magnetic dipole on a nonlinear thermally radiative ferromagnetic liquidﬂowing over a stretched surface in the presence of Brownian motion and thermophoresis are *** means of a similarity transformation,ordinary differential equations are derived and solved afterwards using a numerical(the BVP4C)*** impact of various parameters,namely the velocity,temperature,concentration,is presented *** is shown that the nanoparticles properties,in conjunction with the magnetic dipole effect,can increase the thermal conductivity of the engineered nanoﬂuid and,consequently,the heat *** with earlier studies indicates high accuracy and effectiveness of the numerical *** increase in the Brow-nian motion parameter and thermophoresis parameter enhances the concentration and the related boundary *** skin-friction rises when the viscosity parameter is increased.A larger value of the ferromagnetic para-meter results in a higher skin-friction and,vice versa,in a smaller nusselt number.

关键词： Brownian motion thermo-phoresis radiation magnetic dipole BVP4C non-linear

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Controlled source time domain electromagnetic methods for seafloor electric conductivity mapping

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中国有色金属学会会刊：英文版 2000年第2期10卷 270-274页

作者： YAnG Jian wen, R.n.Edwards Geophysics Division, department of Physics, university of Toronto, Toronto, ontario, M5s 1A7, canada Univ Toronto Dept Phys Div Geophys Toronto ON M5S 1A7 Canada

Theoretical studies of some controlled source electromagnetic methods, especially the horizontal coaxial magnetic dipole dipole and horizontal collinear electric dipole dipole electromagnetic methods, which are capable of accurately measuring the relatively low conductivity of the seafloor were reviewed. Marine electromagnetic instrumentations, especially the time domain horizontal magnetic dipole dipole system and horizontal electric dipole dipole system which have been designed and constructed in the Geophysics Division of the university of Toronto, were provided with applications to geotechnical studies on the shelf and deep ocean surveys near the mid ocean ridges.

关键词： seafloor resources electric conductivity maping instruments

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