| 肌动蛋白纤维束力学性质研究 |
| Alternative Title | Study of Mechanical Properties of F-actin Bundles
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| 王晓 |
| Thesis Advisor | 王记增
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| 2014-05-24
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| Degree Grantor | 兰州大学
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| Place of Conferral | 兰州
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| Degree Name | 硕士
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| Keyword | 肌动蛋白纤维束
力学性质
蠕虫链模型
统计热力学
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| 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 Abstract | As 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... |
| URL | 查看原文
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| Language | 中文
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| Document Type | 学位论文
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| Identifier | https://ir.lzu.edu.cn/handle/262010/226298
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| Collection | 土木工程与力学学院
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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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