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2005 27th Annual International Conference of the Engineering in Medicine and Biology Society, IEEE-EMBS 2005

作者： Kim, Yongchul Youm, Youngil Schmit, Brian D. Department of Mechanical Engineering Pohang University of Science and Technology Pohang Korea Republic of Department of Biomedical Engineering Marquette University Milwaukee WI United States Sensory Motor Performance Program Rehabilitation Institute of Chicago Chicago IL United States Department of Physical Medicine and Rehabilitation Northwestern University Medical School Chicago IL United States

ISBN: (纸本)0780387406

We identified torque response of flexion reflex associated with hip angle and angular velocity in 6 subjects with chronic SCI and developed two dimensional dynamic model with three segments, thigh, shank and foot. Influences of stimulation parameters such as amplitude, frequency and duration time of pulse train for producing swing motion of lower limb were investigated with response surface method to obtain optimal solutions. The initial hip flexion velocity (F-value > 19.0) and knee flexion velocity (F-value > 9.0) were clearly significant, while the initial hip angle was indistinguishable from the estimated amount of error. When the limb motion was simulated with initial hip and knee flexion velocity, the stimulation amplitude was increased 53%, the frequency was decreased 37% and the duration time was decreased 33% with respect to no initial condition. © 2005 IEEE.

关键词： Motion estimation

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Finite Element Simulation of Sheet Metal Forming Process Using Local Interpolation for Tool Surfaces

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AIP Conference Proceedings 2005年第1期778卷 185-190页

作者： Takayuki Hama Masato Takamura Cristian Teodosiu Akitake Makinouchi Hirohiko Takuda *Department of Energy and Science Technology Kyoto University Yoshida‐Honmachi Sakyo‐ku Kyoto 606‐8501 Japan ¶Integrated Volume‐CAD System Program The Institute of Physical and Chemical Research2‐1 Hirosawa Wako‐shi Saitama 351‐0198 Japan †LPMTM‐CNRS University Paris 13 93430 Villetaneuse France

Treatment of contact between a sheet and tools is one of the most difficult problems to deal with in finite‐element simulations of sheet forming processes. In order to obtain more accurate tool models without increasing the number of elements, this paper describes a new formulation for contact problems using interpolation proposed by Nagata for tool surfaces. A contact search algorithm between sheet nodes and the interpolated tool surfaces was developed and was introduced into the static‐explicit elastoplastic finite‐element method code STAMP3D. Simulations of a square cup deep drawing process with a very coarsely discretized punch model were carried out. The simulated results showed that the proposed algorithm gave the proper drawn shape, demonstrating the validity of the proposed algorithm.

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Numerical Investigation on Formability of Ellipse Deep Drawing by Sheet Hydroforming

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AIP Conference Proceedings 2005年第1期778卷 549-554页

作者： Hiroshi Utsugi Takayuki Hama Motoo Asakawa Tomohiro Hatakeyama Akitake Makinouchi Hiroyuki Amino Yang Lu *Graduate School of Science and Engineering Waseda University 3‐4‐1 Ohkubo Shinjuku‐ku Tokyo 169‐8555 Japan ¶Department of Energy and Science Technology Kyoto University Yoshida‐Honmachi Sakyo‐ku Kyoto 606‐8501 Japan †Department of Mechanical Engineering Waseda University 3‐4‐1 Ohkubo Shinjuku‐ku Tokyo 169‐8555 Japan ‡Integrated Volume‐CAD System Program The Institute of Physical and Chemical Research 2‐1 Hirosawa Wako Saitama 351‐0198 Japan oundAmino Corporation 555 Misonodaira Fujinomiya Shizuoka 418‐0004 Japan

This paper presents the numerical investigation on the formability of the sheet hydroforming by a finite element method. The finite element method code for sheet hydroforming simulation was developed based on the static‐explicit finite‐element method code STAMP3D. Experiments and Simulations of ellipse deep drawings were performed. The simulated thickness strain distribution which has two local thinnings at the punch shoulder and at the upper part of the side wall well agreed with the experimental one, thus demonstrating the validity of the developed code. Moreover, the effects of the friction increasing effect which is one of the main features in the sheet hydroforming on the formability were examined by comparing the results between the simulations with the friction coefficient μ=0 and those with μ=0.15. When μ=0 was employed, the local thinning at the upper part of the side wall disappeared. This showed that the occurring the two local thinnings in the sheet hydroforming was originated in the friction increasing effect.

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High-resolution x-ray absorption spectroscopy studies of metal compounds in neurodegenerative brain tissue

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Journal of Physics: Conference Series 2005年第1期17卷

作者： J F Collingwood A Mikhaylova M R Davidson C Batich W J Streit T Eskin J Terry R Barrea R S Underhill J Dobson Institute for Science & Technology in Medicine Keele University Thornburrow Drive Hartshill Stoke-on-Trent ST4 7QB United Kingdom Department of Biomedical Engineering University of Florida Gainesville Florida USA 32611 Department of Materials Science & Engineering University of Florida Gainesville Florida USA 32611 Department of Neuroscience University of Florida Gainesville Florida USA 32611 Department of Pathology Immunology and Laboratory Medicine University of Florida College of Medicine Gainesville FL 32610 Biological Chemical and Physical Sciences Illinois Institute of Technology Chicago Illinois USA 60616 Biophysics Collaborative Access Team APS/435B/Sector 18 Argonne National Laboratory 9700 S. Cass Avenue Argonne Illinois USA 60439 DRDC Atlantic PO Box 99000 Stn. Forces Halifax NS B3K 5X5 Canada

Fluorescence mapping and microfocus X-ray absorption spectroscopy are used to detect, locate and identify iron biominerals and other inorganic metal accumulations in neurodegenerative brain tissue at sub-cellular resolution (<5 microns). Recent progress in developing the technique is reviewed. Synchrotron X-rays are used to map tissue sections for metals of interest, and XANES and XAFS are used to characterise anomalous concentrations of the metals in-situ so that they can be correlated with tissue structures and disease pathology. Iron anomalies associated with biogenic magnetite, ferritin and haemoglobin are located and identified in an avian tissue model with a pixel resolution ~5 microns. Subsequent studies include brain tissue sections from transgenic Huntington's mice, and the first high-resolution mapping and identification of iron biominerals in human Alzheimer's and control autopsy brain tissue. Technical developments include use of microfocus diffraction to obtain structural information about biominerals in-situ, and depositing sample location grids by lithography for the location of anomalies by conventional microscopy. The combined techniques provide a breakthrough in the study of both intra- and extra-cellular iron compounds and related metals in tissue. The information to be gained from this approach has implications for future diagnosis and treatment of neurodegeneration, and for our understanding of the mechanisms involved.

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Effect of calcium and phosphorus ion implantation on the corrosion resistance and biocompatibility of titanium

Effect of calcium and phosphorus ion implantation on the cor...

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作者： Krupa, D. Baszkiewicz, J. Kozubowski, J.A. Lewandowska-Szumiel, M. Barcz, A. Sobczak, J.W. Biliński, A. Rajchel, A. Warsaw University of Technology Woloska 141 02-507 Warsaw Poland Department of Biophysics and Human Physiology Centre of Biostructure Research Medical University of Warsaw Chalubińskiego 5 02-004 Warsaw Poland Institute of Electron Technology Al. Lotników 46 02-668 Warsaw Poland Institute of Physical Chemistry Polish Academy of Science Kasprzaka 44/52 01-224 Warsaw Poland Institute of Nuclear Physics Radzikowskiego 152 31-342 Cracow Poland

This paper is concerned with the corrosion resistance and biocompatibility of titanium after surface modification by the ion implantation of calcium or phosphorus or calcium + phosphorus. Calcium and phosphorus ions were implanted in a dose of 1017 ions/cm2. The ion beam energy was 25 keV. The microstructure of the implanted layers was examined by TEM. The chemical composition of the surface layers was determined by XPS and SIMS. The corrosion resistance was examined by electrochemical methods in a simulated body fluid (SBF) at a temperature of 37°C. The biocompatibility was evaluated in vitro. As shown by TEM results, the surface layers formed during calcium, phosphorus and calcium + phosphorus implantation were amorphous. The results of the electrochemical examinations (Stern's method) indicate that the calcium, phosphorus and calcium + phosphorus implantation into the surface of titanium increases its corrosion resistance in stationary conditions after short- and long-term exposures in SBF. Potentiodynamic tests show that the calcium-implanted samples undergo pitting corrosion during anodic polarisation. The breakdown potentials measured are high (2.5 to 3 V). The good biocompatibility of all the investigated materials was confirmed under the specific conditions of the applied examination, although, in the case of calcium implanted titanium it was not as good as that of non-implanted titanium. © 2004 - IOS Press and the authors. All rights reserved.

关键词： Ion implantation

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Finite Size Effects on Thermal Denaturation of Globular Proteins

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physical Review Letters 2004年第26期93卷 268107-268107页

作者： Mai Suan Li Dmitri K. Klimov D. Thirumalai Institute of Physics Polish Academy of Sciences Al. Lotnikow 32/46 02-668 Warsaw Poland Institute for Physical Science and Technology University of Maryland College Park Maryland 20742 USA Bioinformatics and Computational Biology Program School of Computational Sciences George Mason University Manassas Virginia 20110 USA

Finite size effects on the cooperative thermal denaturation of proteins are considered. A dimensionless measure of cooperativity, Ωc, scales as Nζ, where N is the number of amino acids. Surprisingly, we find that ζ is universal with ζ=1+γ, where the exponent γ characterizes the divergence of the susceptibility for a self-avoiding walk. Our lattice model simulations and experimental data are consistent with the theory. Our finding rationalizes the marginal stability of proteins and substantiates the earlier predictions that the efficient folding of two-state proteins requires TF≈Tθ, where Tθ and TF are the collapse and folding transition temperatures, respectively.

关键词： .stability Transitions PRL ending susceptibility experimental data Thermal denaturation folding transition exponent unfolded native state Globular Proteins cooperativity two-state NBA

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Publisher’s Note: “Polymer-specific effects of bulk relaxation and stringlike correlated motion in the dynamics of a supercooled polymer melt” [J. Chem. Phys. 119, 5290 (2003)]

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The Journal of Chemical Physics 2004年第14期120卷 6798-6798页

作者： M. Aichele Y. Gebremichael F. W. Starr J. Baschnagel S. C. Glotzer Institut Charles Sadron 6 rue Boussingault 67083 Strasbourg France Institut für Physik Johannes Gutenberg-Universität 55099 Mainz Germany Department of Chemical Engineering University of Michigan Ann Arbor Michigan 48109 Chemical Physics Program Institute for Physical Sciences and Technology University of Maryland College Park Maryland 20742 Center for Theoretical and Computational Materials Science and Polymers Division National Institute of Standards and Technology Gaithersburg Maryland 20899 Departments of Chemical Engineering and Materials Science and Engineering University of Michigan Ann Arbor Michigan 48109

M. Aichele, Y. Gebremichael, F. W. Starr, J. Baschnagel, S. C. Glotzer; Publisher’s Note: “Polymer-specific effects of bulk relaxation and stringlike correlated

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GAUGE METHOD FOR VISCOUS INCOMPRESSIBLE FLOWS

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Communications in Mathematical sciences 2003年第2期1卷 317-332页

作者： Weinan, E. Liu, Jian-Guo Department of Mathematics and Program in Applied and Computational Mathematics Princeton University Princeton 08544 NJ United States Institute for Physical Science and Technology and Department of Mathematics University of Maryland College Park 20742 MD United States

We present a new formulation of the incompressible Navier-Stokes equation in terms of an auxiliary field that differs from the velocity by a gauge transformation. The gauge freedom allows us to assign simple and specific boundary conditions for both the auxiliary field and the gauge field, thus eliminating the issue of pressure boundary condition in the usual primitive variable formulation. The resulting dynamic and kinematic equations can then be solved by standard methods for heat and Poisson equations. A normal mode analysis suggests that in contrast to the classical projection method, the gauge method does not suffer from the problem of numerical boundary layers. Thus the subtleties in the spatial discretization for the projection method are removed. Consequently, the projection step in the gauge method can be accomplished by standard Poisson solves. We demonstrate the efficiency and accuracy of the gauge method by several numerical examples, including the flow past cylinder © 2003 International Press

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Addendum to “Hypothesis: a glycoprotein-degradation complex formed by protein–protein interaction involves cytoplasmic peptide: N -glycanase” [Biochem. Biophys. Res. Commun. 302 (2003) 1–5]

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Biochemical and Biophysical Research Communications 2003年第2期303卷 732-732页

作者： Tadashi Suzuki William J Lennarz Undergraduate Program for Bioinformatics and Systems Biology and Department of Biophysics and Biochemistry Graduate School of Science University of Tokyo and PRESTO Japan Science and Technology Corporation (JST) Hongo 7-3-1 Bunkyo-ku Tokyo 113-0033 Japan Department of Biochemistry and Cell Biology and the Institute for Cell and Developmental Biology State University of New York at Stony Brook Stony Brook NY 11794-5215 USA

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physical Review E 2001年第5期64卷 051503-051503页

作者： Y. Gebremichael T. B. Schrøder F. W. Starr S. C. Glotzer Center for Theoretical and Computational Materials Science and Polymers Division National Institute of Standards and Technology Gaithersburg Maryland 20899 Chemical Physics Program Institute for Physical Sciences and Technology University of Maryland College Park Maryland 20742 Departments of Chemical Engineering and Materials Science and Engineering University of Michigan Ann Arbor Michigan 48109

In recent years, experimental and computational studies have demonstrated that the dynamics of glass-forming liquids are spatially heterogeneous, exhibiting regions of temporarily enhanced or diminished mobility. Here we present a detailed analysis of dynamical heterogeneity in a simulated “bead-spring” model of a low-molecular-weight polymer melt. We investigate the transient nature and size distribution of clusters of “mobile” chain segments (monomers) as the polymer melt is cooled toward its glass transition. We also explore the dependence of this clustering on the way in which the mobile subset is defined. We show that the mean cluster size is time dependent with a peak at intermediate time, and that the mean cluster size at the peak time grows with decreasing temperature T. We show that for each T a particular fraction of particles maximizes the mean cluster size at some characteristic time, and this fraction depends on T. The growing size of the clusters demonstrates the growing range of correlated motion, previously reported for this same system [C. Beneman et al. Nature (London) 399, 246 (1999)]. The distribution of cluster sizes approaches a power law near the mode-coupling temperature, similar to behavior reported for a simulated binary mixture and a dense colloidal suspension, but with a different exponent. We calculate the correlation length of the clusters, and show that it exhibits similar temperature- and time-dependent behavior as the mean cluster size, with a maximum at intermediate time. We show that the characteristic time of the maximum cluster size follows the scaling predicted by mode-coupling theory (MCT) for the β time scale, revealing a possible connection between spatially heterogeneous dynamics and MCT.

关键词： .size distribution clustering intermediate segments glass transition investigate toward glass-forming monomers Polymer Melt Dynamical Heterogeneity spatially heterogeneous mean cluster correlated dynamics mobile subset peak time

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