兰州大学机构库 >土木工程与力学学院
肌动蛋白纤维束力学性质研究
Alternative TitleStudy of Mechanical Properties of F-actin Bundles
王晓
Thesis Advisor王记增
2014-05-24
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Keyword肌动蛋白纤维束 力学性质 蠕虫链模型 统计热力学
Abstract肌动蛋白纤维束作为一类复杂亚细胞结构,其力学性质在细胞生理过程中起着重要的作用。目前,针对肌动蛋白纤维束的力学性质,人们从统计热力学或连续介质力学出发来研究,但是由于肌动蛋白纤维束具有聚合物的特性,又同时具有复杂束状复合结构,因此我们建立了将统计热力学理论与连续介质结构力学理论结合的新模型来实现这一目的。 在正常的溶液环境中,肌动蛋白纤维束即有整体的低阶模态扰动,每根纤维又具有高阶模态的微小扰动。首先,通过考虑单根纤维微小扰动的影响,我们基于受限空间聚合物理论得到了纤维束的等效杨氏模量。并且研究了当纤维束的横截面为正四边形和正六边形时的拉伸统计热力学行为。其次,通过建立统计热力学与连续介质结构力学耦合的理论模型,得到了描述纤维束统计热力学弯曲刚度的纤维束持续长度与长度及外加拉力之间的非线性奇异定量依赖关系。最后,将纤维束看作是一个具有复杂微结构的束状聚合物分子链,通过统计热力学手段得到了力与拉伸变形之间的定量依赖关系及等效拉伸刚度。通过比较发现:当纤维间剪切刚度较大时结论基本一致,当剪切刚度较小时表现出了差异性。因此单一纤维的微小扰动对于结合较为松散的纤维束的力学性质有着很大的影响。
Other AbstractAs a class of complex sub-cellular structures , the mechanical properties of F-actin bundles plays a crucial role in many fundamental cellular processes, such as cell migration, intracellular transport, regulation of cell adhesion and maintenance of cell morphology and so on. Multiple skeletal substructure cells , such as microvilli , stress fibers , stereocilia , filopodia , etc., are formed by F-actin bundles. These sub- frame structures have respective different properties since different number of fibers, the length of fibers and different types of actin binding proteins. Currently, people tend to study the mechanical properties of F-actin bundles from a single continuum mechanics or statistical thermodynamics. However F-actin bundle is extremely flexible in the microscale and effected easily by thermal disturbance, so they have the characteristcs of polymer. At the same time, F-actin bundles have complex composite bundle structures which differ from classic polymer molecule. So in order to achieve the precise quantitative description of F-actin bundle’s mechanical properties, we first established new model which combine the statistical thermodynamic theory and continuum structural mechanics theory to realize this goal in this paper. In general solution environment, F-actin bundle not only has low modes of whole bundle’s deformation, but also has each fiber’s high modes of deformation. Firstly, we obtain the equivalent Young's modulus of F-actin bundle which based on confined space polymer theory by considering the impact of a single fiber’s tiny fluctuation. Meanwhile we study the tensile behavior of statistical thermodynamics of F-actin bundle packing with chains squarely and hexagonally. Through these calculation, we find the tiny fluctuation of single fiber have great impact on stretching stiffness of F-actin bundle which reflect strong nonlinear hyper-elastic properties. Secondly, through the establishment of theoretical model of coupled statistical thermodynamic theory and continuum structural mechanics theory, we get the nonlinear singular quantitative dependencies of persistence length which describe statistical thermodynamic bending stiffness and contour length, persistence length and tensile III force. These properties show that the persistence length increas...
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Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/226298
Collection土木工程与力学学院
Recommended Citation
GB/T 7714
王晓. 肌动蛋白纤维束力学性质研究[D]. 兰州. 兰州大学,2014.
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