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Inhibition and enhancement of neural regeneration by chondroitin sulfate proteoglycans

Neural Regeneration Research 2017年第5期12卷 687-691页

作者： Heikki Rauvala mikhail Paveliev Juha Kuja-Panula Natalia Kulesskaya Neuroscience Center University of Helsinki Helsinki Finland Department of Biological and Environmental Sciences University of Helsinki Helsinki Finland

The current dogma in neural regeneration research implies that chondroitin sulfate proteoglycans（CSPGs） inhibit plasticity and regeneration in the adult central nervous system（CNS）. We argue that the role of the CSPGs can be reversed from inhibition to activation by developmentally expressed CSPG-binding factors. Heparin-binding growth-associated molecule（HB-GAM; also designated as pleiotrophin） has been studied as a candidate molecule that might modulate the role of CSPG matrices in plasticity and regeneration. Studies in vitro show that in the presence of soluble HB-GAM chondroitin sulfate（CS） chains of CSPGs display an enhancing effect on neurite outgrowth. Based on the in vitro studies, we suggest a model according to which the HB-GAM/CS complex binds to the neuron surface receptor glypican-2, which induces neurite growth. Furthermore, HB-GAM masks the CS binding sites of the neurite outgrowth inhibiting receptor protein tyrosine phosphatase sigma（PTPσ）, which may contribute to the HB-GAM-induced regenerative effect. In vivo studies using two-photon imaging after local HB-GAM injection into prick-injury of the cerebral cortex reveal regeneration of dendrites that has not been previously demonstrated after injuries of the mammalian nervous system. In the spinal cord, two-photon imaging displays HB-GAM-induced axonal regeneration. Studies on the HB-GAM/CS mechanism in vitro and in vivo are expected to pave the way for drug development for injuries of brain and spinal cord.

关键词： CNS injury axon regeneration dendrite regeneration proteoglycans aggrecan glypican HB-GAM pleiotrophin PTEN

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Difference in formation of plasma electrolytic oxidation coatings on MgLi alloy in comparison with pure Mg

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Journal of Magnesium and Alloys 2021年第5期9卷 1745-1760页

作者： Ting Wu Carsten Blawert Xiaopeng Lu Maria Serdechnova mikhail L.Zheludkevich Institute of Surface Science Helmholtz-Zentrum Hereon21502 GeesthachtGermany Shenyang National Laboratory for Materials Science Northeastern University110819 ShenyangChina Institute for Materials Science Faculty of EngineeringKiel UniversityKaiserstrasse 224143 KielGermany

In order to study the substrate lattice structure(Li addition)on the growth of plasma electrolytic oxidation(PEO)coatings,Mg Li alloy(11.36 wt.%of Li,cubic)and pure Mg(hexagonal)were treated under a pulsed direct PEO mode in a phosphate electrolyte for different periods of *** results revealed that the presence of Li and Li-rich phases in the cubic Mg alloy seems to be essential for the treatment result rather than the original lattice structure.A modified discharge behavior of Mg Li alloy finally led to a different microstructure of the *** unstable coatings of Mg Li alloy tended to dissolve rapidly though shared the similar composition to that of pure *** was incorporated only in the primary conversion products at the interface of coating/Mg *** spite of the advanced efficiency of energy input during processing,the more porous and thinner PEO coatings on the Mg Li alloy were less resistant to abrasion and corrosion.

关键词： Plasma electrolytic oxidation Magnesium lithium alloy Pure magnesium Microstructure

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A Pressure Relaxation Closure Model for One-Dimensional, Two-Material Lagrangian Hydrodynamics Based on the Riemann Problem

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Communications in Computational Physics 2010年第5期7卷 927-976页

作者： James R.Kamm mikhail J.Shashkov Applied Physics Division Los Alamos National LaboratoryLos AlamosNM 87545USA Theoretical Division Los Alamos National LaboratoryLos AlamosNM 87545USA

Despite decades of development, Lagrangian hydrodynamics of strengthfree materials presents numerous open issues, even in one dimension. We focus on theproblem of closing a system of equations for a two-material cell under the assumptionof a single velocity model. There are several existing models and approaches, eachpossessing different levels of fidelity to the underlying physics and each exhibitingunique features in the computed solutions. We consider the case in which the changein heat in the constituent materials in the mixed cell is assumed equal. An instantaneous pressure equilibration model for a mixed cell can be cast as four equations infour unknowns, comprised of the updated values of the specific internal energy andthe specific volume for each of the two materials in the mixed cell. The unique contribution of our approach is a physics-inspired, geometry-based model in which theupdated values of the sub-cell, relaxing-toward-equilibrium constituent pressures arerelated to a local Riemann problem through an optimization principle. This approachcouples the modeling problem of assigning sub-cell pressures to the physics associated with the local, dynamic evolution. We package our approach in the frameworkof a standard predictor-corrector time integration scheme. We evaluate our model using idealized, two material problems using either ideal-gas or stiffened-gas equationsof state and compare these results to those computed with the method of Tipton andwith corresponding pure-material calculations.

关键词： Lagrangian hydrodynamics compressible flow multi-material flow pressure relaxation

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Simulation of Secondary Electron and Backscattered Electron Emission in A6 Relativistic Magnetron Driven by Different Cathode

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Plasma Science and Technology 2015年第1期17卷 64-70页

作者：刘美琴李博轮刘纯亮 Fuks mikhail Edl SCHAMILOGLU Key Laboratory of Physical Electronics and Devices of the Ministry of Education Xi'an Jiaotong University Department of Electrical and Computer Engineering University of New Mexico

Prticle-in-cell（PIC） simulations demonstrated that,when the relativistic magnetron with diffraction output（MDO） is applied with a 410 kV voltage pulse,or when the relativistic magnetron with radial output is applied with a 350 kV voltage pulse,electrons emitted from the cathode with high energy will strike the anode block *** emitted secondary electrons and backscattered electrons affect the interaction between electrons and RF fields induced by the operating modes,which decreases the output power in the radial output relativistic magnetron by about 15%（10%for the axial output relativistic magnetron）,decreases the anode current by about 5%（5%for the axial output relativistic magnetron）,and leads to a decrease of electronic efficiency by 8%（6%for the axial output relativistic magnetron）.The peak value of the current formed by secondary and backscattered current equals nearly half of the amplitude of the anode current,which may help the growth of parasitic modes when the applied magnetic field is near the critical magnetic field separating neighboring ***,mode competition becomes more serious.

关键词： secondary electron and backscattered electron emission relativistic magnetron mode competition critical magnetic field output power anode current electronic efficiency transparent cathode solid cathode

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A localized Fourier collocation method for 2D and 3D elliptic partial differential equations:Theory and MATLAB code

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International Journal of Mechanical System Dynamics 2022年第4期2卷 339-351页

作者： Yan Gu Zhuojia Fu mikhail V.Golub Department of Computational Mathematics School of Mathematics and StatisticsQingdao UniversityQingdaoChina Department of Engineering Mechanics College of Mechanics and MaterialsHohai UniversityNanjingChina Department of Applied Mathematics Institute for MathematicsMechanics and InformaticsKuban State UniversityKrasnodarRussian Federation

A localized Fourier collocation method is proposed for solving certain types of elliptic boundary value *** method first discretizes the entire domain into a set of overlapping small subdomains,and then in each of the subdomains,the unknown functions and their derivatives are approximated using the pseudo-spectral Fourier collocation *** key idea of the present method is to combine the merits of the quick convergence of the pseudo-spectral method and the high sparsity of the localized discretization technique to yield a new framework that may be suitable for large-scale *** present method can be viewed as a competitive alternative for solving numerically large-scale boundary value problems with complex-shape *** numerical experiments involving Poisson,Helmholtz,and modified-Helmholtz equations in both two and three dimensions are presented to demonstrate the accuracy and efficiency of the proposed method.

关键词： meshless method collocation method Fourier basis functions large-scale problem

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Reduction of friction by normal oscillations.Ⅱ.In-plane system dynamics

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Friction 2017年第2期5卷 534-535,536页

作者： Xinyu MAO Valentin L.POPOV Jasminka STARCEVIC mikhail POPOV Technische Universit(a)t Berlin Berlin 10623 GermanyTsinghua University Beijing 100084 China Technische Universit(a)t Berlin Berlin 10623 GermanyTomsk Polytechnic University Tomsk 634050 RussiaTomsk State University Tomsk 634050 Russia Technische Universit(a)t Berlin Berlin 10623 GermanyTomsk State University Tomsk 634050 Russia

The influence of out-of-plane oscillations on friction is a well-known phenomenon that has been studied extensively with various experimental methods,e.g.,pin-on-disk ***,existing theoretical models have yet achieved only qualitative correspondence with *** we argue that this may be due to the system dynamics (mass and tangential stiffness) of the pin or other system components being *** paper builds on the results of a previous study [19] by taking the stiffness and resulting dynamics of the system into *** main governing parameters determining macroscopic friction,including a dimensionless oscillation amplitude,a dimensionless sliding velocity and the relation between three characteristic frequencies (that of externally excited oscillation and two natural oscillation frequencies associated with the contact stiffness and the system stiffness) are *** the limiting cases of a very soft system and a very stiff system,our results reproduce the results of previous *** between these two limiting cases there is also a resonant case,which is studied here for the first *** resonant case is notable in that it lacks a critical sliding velocity,above which oscillations no longer reduce *** obtained for the resonant case are qualitatively supported by experiments.

关键词： sliding friction out-of-plane oscillation stiffness system dynamics macroscopic friction coefficient

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Positivity-Preserving Runge-Kutta Discontinuous Galerkin Method on Adaptive Cartesian Grid for Strong Moving Shock

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Numerical Mathematics(Theory,Methods and Applications) 2016年第1期9卷 87-110页

作者： Jianming Liu Jianxian Qiu mikhail Goman Xinkai Li Meilin Liu School of Mathematics and Statistics Jiangsu Normal UniversityXuzhou 221116China Faculty of Technology De Montfort UniversityLeicester LE19BHEngland School of Mathematical Sciences and Fujian Provincial Key Laboratory of Mathematical Modeling and High-Performance Scientific Computation Xiamen UniversityXiamen 361005China Shanghai Institute of Satellite Engineering Shanghai 200240China

In order to suppress the failure of preserving positivity of density or pres-sure,a positivity-preserving limiter technique coupled with h-adaptive Runge-Kutta discontinuous Galerkin(RKDG)method is developed in this *** a method is implemented to simulate flows with the large Mach number,strong shock/obstacle interactions and shock *** Cartesian grid with ghost cell immersed boundary method for arbitrarily complex geometries is also *** ap-proach directly uses the cell solution polynomial of DG finite element space as the interpolation *** method is validated by the well documented test ex-amples involving unsteady compressible flows through complex bodies over a large Mach *** numerical results demonstrate the robustness and the versatility of the proposed approach.

关键词： Discontinuous Galerkin method adaptive Cartesian grid positivity-preserving im-mersed boundary method complex geometry

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The Objective Assessment of Event-Related Potentials:An Influence of Chronic Pain on ERP Parameters

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Neuroscience Bulletin 2023年第7期39卷 1105-1116页

作者： Maksim Zhuravlev mikhail Novikov Ruzanna Parsamyan Anton Selskii Anastasiya Runnova Coordinating Center for Fundamental Research National Medical Research Center for Therapy and Preventive MedicineMoscow 101000Russia Institute of Physics Saratov State UniversitySaratov 410012Russia Department of Fundamental Research in Neurocardiology Institute of Cardiological ResearchSaratov State Medical UniversitySaratov 410012Russia

The article presents an original method for the automatic assessment of the quality of event-related potentials(ERPs),based on the calculation of the coefficientε,which describes the compliance of recorded ERPs with some statistically significant *** method was used to analyze the neuropsychological EEG monitoring of patients suffering from *** frequency of migraine attacks was correlated with the spatial distribution of the coefficientsε,calculated for EEG *** than 15 migraine attacks per month was accompanied by an increase in calculated values in the occipital *** with infrequent migraines exhibited maximum quality in the frontal *** automatic analysis of spatial maps of the coefficientεdemonstrated a statistically significant difference between the two analyzed groups with different means of migraine attack numbers per month.

关键词： Event-related potential Chronic migraine ERP quality Automatic evaluation

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Polyhydroxybutyrate/Hydroxyapatite Highly Porous Scaffold for Small Bone Defects Replacement in the Nonload-bearing Parts

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Journal of Bionic Engineering 2017年第4期14卷 648-658页

作者： Fedor Senatov Natalia Anisimova mikhail Kiselevskiy Aleksey Kopylov Viktor Tcherdyntsev Aleksey Maksimkin National University of Science and Technology MISIS Leninskiy pr. 4 Moscow 119049 Russian Federation N.N. Blokhin Russian Cancer Research Center Kashirskoye sh. 23 Moscow 115478 Russian Federation

In the present work, Polyhydroxybutyrate （PHB）/Hydroxyapatite （HA） porous composites （10%, 20%, 30 %, 40%, 50% weight HA） were obtained by sintering. PHB/20% HA optimally combines satisfactory mechanical properties with a high content of the bioactive component （HA）. Porous PHB/20% HA scaffolds have shown high mechanical properties （compressive strength of 106 MPa and Young＇s modulus of 901 MPa）. A high volume fraction of interconnected pores （〉 50 vol.%） was achieved with pore size of 50 grn - 500 gm. Biocompatibility of porous pure PHB and PHB/20%HA, as its osseointegration were assessed in vitro and after implantation in laboratory animals. PHB/20% HA （-5% ＋ 0.9%） and pure PHB ~3% ~ 1.4%） samples after 24 hours of incubation with human leucocytes showed no significant level of cytotoxicity when p = 0.648 （p-value）. In vitro massive adhesion of mouse Multipotent Mesenchymal Stromal Cells （MMSC） to the surface of both porous samples was shown. PHB/20% HA induced more intensive MMSC proliferation compared to pure PHB, which are 31% ＋ 6.1% and 20% ＋ 5.7 % respectively when p = 0.039. We observed the resorption （implant surface area was reduced by 49 %） and integration of the porous PHB/20% HA samples into surrounding tissues after 30 days of implantation. The signs of osteoclasts accumulation, neo-angigenesis and new bone formation were observed, which make PHB/20% HA promising for bone tissue engineering.

关键词： polyhydroxybutyrate hydroxyapatite scaffold porous structure implant bone regeneration

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Wolf phase tomography(WPT) of transparent structures using partially coherent illumination

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Light(Science & Applications) 2020年第1期9卷 656-664页

作者： Xi Chen mikhail E.Kandel Chenfei Hu Young Jae Lee Gabriel Popescu Quantitative Light Imaging Laboratory Beckman Institute for Advanced Science and TechnologyDepartment of Electrical and Computer EngineeringUniversity of Illinois at Urbana-ChampaignUrbanaIL 61801USA

In 1969,Emil Wolf proposed diffraction tomography using coherent holographic imaging to extract 3D information from transparent,inhomogeneous *** the same era,the Wolf equations were first used to describe the propagation correlations associated with partially coherent *** these two concepts,we present Wolf phase tomography(WPT),which is a method for performing diffraction tomography using partially coherent *** reconstruction works directly in the space-time domain,without the need for Fourier transformation,and decouples the refractive index(RI)distribution from the thickness of the *** demonstrate the WPT principle using the data acquired by a quantitative-phase-imaging method that upgrades an existing phase-contrast microscope by introducing controlled phase shifts between the incident and scattered *** illumination field in WPT is partially spatially coherent(emerging from a ring-shaped pupil function)and of low temporal coherence(white light),and as such,it is well suited for the Wolf *** three intensity measurements corresponding to different phase-contrast frames,the 3D RI distribution is obtained immediately by computing the Laplacian and second time derivative of the measured complex correlation *** validate WPT with measurements of standard samples(microbeads),spermatozoa,and live neural *** high throughput and simplicity of this method enables the study of 3D,dynamic events in living cells across the entire multiwell plate,with an RI sensitivity on the order of 10^(−5).

关键词： WPT coherent illumination

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