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1.
作为一种广谱表达的细胞粘附分子, I型跨膜糖蛋白CD44(cluster of differentiation 44)参与细胞增殖、分化、迁移, 血管生成等生物学过程,对于介导细胞信号转导, 调节组织稳态等功能具有关键作用. 特别地,CD44-选择素、CD44 -透明质酸相互作用介导的细胞粘附动力学在经典炎症反应、肿瘤转移或组织特异的肝脏免疫中具有重要作用.该综述分别从细胞层次粘附动力学、二维与三维条件下的分子层次反应动力学、原子层次微观结构以及胞内信号转导通路等方面综述了CD44 -选择素、CD44 -透明质酸相互作用的研究进展及尚待回答的生物力学问题.力学、物理因素对生命活动的不可或缺性逐渐被研究者们接受,力学医学、力学免疫学、力学组学等新概念相继提出. 生理、病理条件下,CD44 -配体相互作用介导的细胞粘附必将受到血流剪切、基底硬度等力学、物理微环境的调控,但是其调控机制还远不清楚. 基于此,本文就CD44 -配体相互作用相关的未来研究方向做出展望, 主要包括:力学、物理因素如何调控CD44 -配体相互作用介导的细胞粘附动力学及其内在机制;CD44 -配体相互作用反应动力学的力学调控规律及结构基础是什么;以及力学作用下CD44 -配体相互作用原子层次的微观结构如何发生动态演化.本文可为深入理解CD44 -配体相互作用的生物学功能及其结构功能关系提供线索.   相似文献   

2.
张欢  赵国清  冯锦腾  林敏 《力学进展》2023,53(1):48-153
细胞膜是细胞与外部环境进行物质与能量交换的界面,是调节细胞正常生命活动的重要结构基础.细胞膜上力敏感受体可通过力学作用方式参与并影响细胞的力信号转导等功能.整合素和钙黏素是细胞膜上典型的力敏感受体,可介导细胞与细胞周围基质或邻近细胞发生力学作用,并将力学刺激信号转导为生化信号,进而激活细胞内一系列应答反应,最终影响细胞生长、分化、增殖、凋亡和迁移等功能.力敏感受体介导细胞功能调控研究已成为探索细胞主动响应外界复杂力学微环境的力学生物学机制的关键,为进一步深入认识生理和病理状态下细胞功能变化规律,为揭示疾病的发生、发展机制提供重要的力学生物学理论与实验依据.本文总结了力敏感受体介导细胞功能调控的国内外研究进展;介绍了黏附界面处典型力敏感受体的结构和功能;总结了这些力敏感受体参与的细胞力信号感知与响应的数理模型;概述了细胞通过力敏感受体进行力学信号转导的过程;介绍了黏附介导细胞功能调控的力学生物学过程和机制;简述了体外构建模拟细胞力学微环境中细胞-细胞外基质和细胞-细胞力学相互作用的技术;指出了力敏感受体介导细胞功能调控的力学生物学研究发展趋势和未来方向.  相似文献   

3.
非线性流体弹性力学研究进展   总被引:5,自引:0,他引:5  
白象忠  郝亚娟 《力学进展》2008,38(5):545-560
流体弹性力学理论是用来描述液体、气体的运动与弹性结构相互作用的学科. 由于其交叉性质, 涉及到人类日常生活中的方方面面, 致使在许多学科和工程领域中都成了主要的研究内容, 并得到了广泛地应用. 本文在阐述研究流体与弹性体相互作用的非线性问题的重要意义及分类方法的基础上, 介绍了非线性流体弹性力学的特征、研究现状和非线性问题的研究方法, 如理论分析法、实验分析法、数值分析法和半解析法等的进展; 介绍了描述介质相互作用的任意拉格朗日-欧拉(ALE)法、相容拉格朗日-欧拉(ULE)法、 单一拉格朗日(SL)法和单一欧拉(SE)法之间的关系, 并且对这些研究方法的优缺点进行了比较; 介绍了非线性流体弹性力学研究的内容和在气动弹性力学、水弹性力学、环境流体弹性力学、 微尺度流体弹性力学和涡激振动等领域中的应用; 阐述了非线性流体弹性力学的发展前景和所面临的任务.  相似文献   

4.
郭春  张西正  徐晓莹 《力学进展》2009,39(2):228-235
力学环境是影响骨组织细胞形成、增殖和功能成熟的一个重要因素. 骨细胞是力学感受细胞, 将力学信号传递给效应细胞; 成骨细胞、破骨细胞为力学效应细胞, 使骨形成和骨吸收处于动态平衡以维持骨力学稳定性. 目前对骨组织细胞间力学调控的机理仍不甚清楚. 综述了骨组织细胞力学生物学作用和细胞间力学调控的一些相关问题. 在概述了成骨细胞、骨细胞和破骨细胞的生物学特性基础上,阐述了骨重建力学调控理论,成骨细胞、骨细胞和破骨细胞生物力学效应和细胞间力学调控最新研究进展. 最后对骨组织细胞三维网络间力学调控研究做出展望.  相似文献   

5.
作为研究DNA等生物大分子链力学行为的模型,考察弹性细杆精确模型截面随弧坐标和时间的运动学问题.给出了基本假定,用映射的概念阐明离散化思想,得到了杆的运动学方程,导出了存在拉/压变形时弯扭度和角速度的关系;定义了截面的虚位移,表示为弧坐标和时间变分均为零的变分法则,在微分和变分运算次序可以交换的前提下,导出了截面虚角位移的导数与截面弯扭度以及角速度变分的关系,为建立超细长弹性杆精确模型动力学的分析力学方法准备理论基础.  相似文献   

6.
陆启韶 《力学进展》2012,42(1):98-99
生命活动属于最复杂的自然界现象。近代生物学研究已从以实验观察为主的方式逐步发展为与生命体的机理性分析密切结合,并且由生物器官组织的宏观形态和表型向生物细胞和分子的微观行为和演变进行深入探讨。随着生物科学实验技术和方法的飞速进步,人们对生物大分子、基因和蛋白质、生物膜的结构和功能等的研究已经积累了相当丰富的知识。由于生命现象都是生物复杂大系统的综合行为的结果,我们必须把生物系统作为一个整体来研究,从系统论的角度进一步探讨细胞的信息、生长、发育、分化、代谢等动态过程以及生物有机体的功能,而不仅把研究重点放在单个的基因, 蛋白质或者器官上。系统生物学就是这样一门研究生物系统的内部组分结构, 以及在各种内、外部条件下这些组分的相互作用和演化规律的学科,是生命科学的一个前沿领域。目前重点是在分子层次上开展对生命现象(例如遗传基因、蛋白质、重大疾病等)的过程和机制的研究,生物化学反应(包括蛋白质—蛋白质相互作用、DNA—蛋白质相互作用等)和生物网络(包括基因网、蛋白质相互作用网、信号转导网、代谢网等)行为在其中起着重要作用。大量的系统生物学研究对象是动态的和随机的,涉及不同的时空尺度下复杂非线性动力学与控制问题。  相似文献   

7.
本文对座标系三维弹性力学问题采用周向与径向解析,轴向离散的半解析数值方法。通过引入部分解析函数,将三维问题归结为一维离散化方程。这种方法能适应于一大类复杂的弹性力学问题,方法简单,计算工作量少。本文用这方法来分析厚壳的三维变形与应力规律,研究大厚跨比的强厚壳的三维弹性理论解,为建立可靠的强厚壳理论提供依据。  相似文献   

8.
胞质分裂力学及其分子生物学机制的研究   总被引:1,自引:0,他引:1  
胞质分裂通过一系列的形态学变化使母细胞一分为二生成两个子细胞, 几乎整个胞质分裂过程都伴随着力学现象.形成刚度或黏弹性互不相同的区域对细胞形态的改变至关重要, 特殊肌动蛋白与交联蛋白是导致细胞局部刚度改变的重要因素.因此有必要深入理解细胞如何变形、 以及促进细胞变形的材料特性及其分子生物学基础. 本文将针对细胞的力学特性、胞质分裂中的力学现象以及分子生物学基础进行讨论.  相似文献   

9.
孙晋美  郭万林 《力学进展》2006,36(4):536-552
围绕包括扫描探针显微镜在内的各种探针技术下核酸、蛋白质等生物分子及生物材料的生物 力学与力 - 电耦合实验研究, 较系统地总结了分子层次或纳米尺度下生物分子和材料的力学性能的扫描 探针显微镜、光镊、磁镊等探针技术的实验研究方法和主要进展, 进而探讨了在``针尖'这 个极小、极特殊环境下的分子生物物理力学研究状况.通过介绍借助探针技术研究相关生物 物质的结构、力学、电学等性能以及提出的一些理论模型, 指出探针技术在生物分子(包括 遗传物质和蛋白质)力学性能、纳米生物材料结构及分子仿生等研究中的广泛意义.提出多 场耦合作用下的针尖的生物物理力学研究必定是将来研究的重点;将针尖的分子生物力学的 物理实验研究与分子物理力学理论、计算科学相结合, 发展分子物理力学虚拟实验技术是本 领域的一个重要发展方向.  相似文献   

10.
在衡量单个细胞力学行为的研究中,越来越多地采用结合实验的数值模拟方法. 在连续 介质力学框架下,发展了一种新的心肌细胞本构模型,并与微管吮吸实验结合,探讨了心肌 细胞的力学特性. 本构模型是对普遍使用的仅能用于小变形分析的标准线性固体模型 的一种扩展,它将超弹性性能引入到黏弹性模型中,用以描述细胞的大变形黏弹性效应. 基 于改进的本构模型,对心肌细胞微管吮吸实验过程进行了有限元模拟,并将计算结果与实验 结果以及经典理论解进行了对比. 结果显示发展的本构模型适合细胞大变形问题的有限 元数值模拟.  相似文献   

11.
As an intriguing interdisciplinary research field,cell and molecular biomechanics is at the cutting edge of mechanics in general and biomechanics in particular.It has the potential to provide a quantitative understanding of how forces and deformation at tissue,cellular and molecular levels affect human health and disease.In this article,we review the recent advances in cell and molecular biomechanics,examine the available computational and experimental tools,and discuss important issues including protein deformation in mechanotransduction,cell deformation and constitutive behavior,cell adhesion and migration,and the associated models and theories.The opportunities and challenges in cell and molecular biomechanics are also discussed.We hope to provide readers a clear picture of the current status of this field,and to stimulate a broader interest in the applied mechanics community.  相似文献   

12.
Focal adhesions (FAs) are large, multi-protein complexes that provide a mechanical link between the cytoskeletal contractile machinery and the extracellular matrix. They exhibit mechanosensitive properties; they self-assemble upon application of pulling forces and dissociate when these forces are decreased. We rationalize this mechano-sensitivity from thermodynamic considerations and develop a continuum framework in which the cytoskeletal contractile forces generated by stress fibers drive the assembly of the FA multi-protein complexes. The FA model has three essential features: (i) the low and high affinity integrins co-exist in thermodynamic equilibrium, (ii) the low affinity integrins within the plasma membrane are mobile, and (iii) the contractile forces generated by the stress fibers are in mechanical equilibrium and change the free energies of the integrins. A general two-dimensional framework is presented and the essential features of the model illustrated using one-dimensional examples. Consistent with observations, the coupled stress fiber and FA model predict that (a) the FAs concentrate around the periphery of the cell; (b) the fraction of the cell covered by FAs increases with decreasing cell size while the total FA intensity increases with increasing cell size; and (c) the FA intensity decreases substantially when cell contractility is curtailed.  相似文献   

13.
Non-linear constitutive models of the elastic forces for a hyperelastic material are presented. Three elastic force models including Neo-Hookean, Mooney-Riblin 2nd, and Yeoh models are derived based on non-linear continuum mechanics. Elastic forces are applied to the three-dimensional absolute nodal coordinate beam element, and the transient response of the cantilever beam is analyzed. Simulation results are compared to experiment data, and the dynamic characteristics of elastic force models presented in this paper are discussed.  相似文献   

14.
Motivated by the application of Winkler-like models for the buckling analysis of embedded carbon nanotubes, an orthotropic Winkler-like model is developed to study the buckling behavior of embedded cytoskeletal microtubules within the cytoplasm. Experimental observations of the buckling of embedded cytoskeletal microtubules reveal that embedded microtubules bear a large compressive force as compared with free microtubules. The present theoretical model predicts that embedded microtubules in an elastic medium bear large compressive forces than free microtubules. The estimated critical pressure is in good agreement with the experimental values of the pressure-induced buckling of microtubules. Moreover, due to the mechanical coupling of microtubules with the surrounding elastic medium, the critical buckling force is increased considerably, which well explains the theory that the mechanical coupling of microtubules with an elastic medium increases compressive forces that microtubules can sustain. The model presented in the paper is a good approximation for the buckling analysis of embedded microtubules.  相似文献   

15.
A general procedure is presented for developing data-based, non-parametric models of non-linear multi-degree-of-freedom, non-conservative, dissipative systems. Two broad classes of methods are discussed: one relying on the representation of the system restoring forces in a polynomial-basis format, and the other using artificial neural networks to map the complex transformations relating the system state variables to the needed system outputs. A non-linear two-degree-of-freedom system is used to formulate the approach under discussion and to generate synthetic data for calibrating the efficiency of the two methods in capturing complex non-linear phenomena (such as dry friction, hysteresis, dead-space non-linearities, and polynomial-type non-linearities) that are widely encountered in the applied mechanics field. Subsequently, a reconfigurable test apparatus was used to generate experimental measurements from a physical non-linear “joint” involving two-dimensional motion (translation and rotation) and complicated interaction forces between the different motion axes, among its internal elements. Both the polynomial-basis approach and the neural network method were used to develop high-fidelity, non-parametric models of the physical test article. The ability of the identified models to accurately “generalize” the essential features of the non-linear system was verified by comparing the predictions of the models with experimental measurements from data sets corresponding to different excitations than those used for identification purposes. It is shown that the identification techniques under discussion can be useful tools for developing accurate simulation models of complex multi-dimensional non-linear systems under broadband excitation.  相似文献   

16.
Venketeswaran  Abhishek  Das  Sonjoy 《Meccanica》2020,55(6):1193-1213

This work models the fluid-structure interactions associated with separating a solid from a soft elastic film in a liquid environment. One side of the soft film is permanently attached to a rigid substrate. The ensuing liquid flow and elastic deformations are derived by considering a system of partial differential equations, that govern the mechanics of the separation process. A finite element based computational scheme is developed to solve the governing equations and predict the resultant forces acting on the solid. It is shown that the resulting forces are influenced by the elasticity of the film for an initial duration and by the viscosity of the liquid at larger times. The proposed model is utilized to shed insights into the mechanics of the separation process in constrained-surface stereolithography process.

  相似文献   

17.
A new notion of stability specially adapted to systems with unilateral contact and Coulomb friction is introduced. Whereas classical stability results in mechanics concern perturbations of the initial data in a classical phase space, we establish here results concerning the trajectories issued from a perturbation of the external forces. In such a context we state a conjecture concerning stability with respect to external forces that we back up by analytical computations in the case of simple models and then by numerical computations for more complex systems.  相似文献   

18.
There are many notional systems for excavating lunar regolith in NASA’s Exploration Vision. Quantitative system performance comparisons are scarce in the literature. This paper focuses on the required forces for excavation and traction as quantitative predictors of system feasibility. The rich history of terrestrial soil mechanics is adapted to extant lunar regolith parameters to calculate the forces. The soil mechanics literature often acknowledges the approximate results from the numerous excavation force models in use. An intent of this paper is to examine their variations in the lunar context. Six excavation models and one traction model are presented. The effects of soil properties are explored for each excavation model, for example, soil cohesion and friction, tool–soil adhesion, and soil density. Excavation operational parameters like digging depth, rake angle, gravity, and surcharge are examined. For the traction model, soil, operational, and machine design parameters are varied to probe choices. Mathematical anomalies are noted for several models. One conclusion is that the excavation models yield such disparate results that lunar-field testing is prudent. All the equations and graphs presented have been programmed for design use. Parameter ranges and units are included.  相似文献   

19.
作用在裂隙中的渗透力分析   总被引:2,自引:0,他引:2  
裂隙岩体中流体对岩体的作用力, 是研究岩体稳定性的重要问题。本文认为流体作用于裂隙壁面上的力包括两部分, 即垂直于裂隙壁面的流体静水压力 (导致裂隙垂向变形)和平行于裂隙壁面的拖曳力 (导致裂隙切向变形), 此拖曳力为面力。文中以单裂隙水流的立方定律为基础, 运用流体力学的动量方程, 推导出了单一平直光滑无充填裂隙、有充填的裂隙及水流和充填物一起运动情况下, 裂隙壁面承受的切向拖曳力公式。该公式对于分析流体对裂隙岩体变形性能及强度的影响具有重要价值。  相似文献   

20.
Recent experiments revealed significant quasi-periodic forces in both the drag and lift directions in a rotated triangular tube bundle subjected to two-phase cross-flow. The quasi-periodic drag forces were found to be related to the momentum flux fluctuations in the main flow path between the cylinders. The quasi-periodic lift forces, on the other hand, are mostly correlated to the oscillation in the wake of the cylinders. In this paper, we develop semi-analytical models for correlating vibration excitation forces to dynamic characteristics of two-phase flow in a rotated triangular tube bundle for a better understanding of the nature of vibration excitation forces. The relationships between the lift or drag forces and the dynamic characteristics of two-phase flow are established through fluid mechanics momentum equations. A model has been developed to correlate the void fraction fluctuation in the main flow path and the dynamic drag forces. A second model has been developed for correlating the oscillation in the wake of the cylinders and the dynamic lift forces. Although still preliminary, each model can predict the corresponding forces relatively well.  相似文献   

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