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T. Zhang^*
Molecular & Cellular Biomechanics, Vol.8, No.3, pp. 169-194, 2011, DOI:10.3970/mcb.2011.008.169
Abstract Cytoplasmic motion assumed as a steady state laminar flow induced by cytoskeleton stretching in a cell is determined and its effect on the mechanical behavior of the cell under externally applied forces is demonstrated. Non-Newtonian fluid is assumed for the multiphase cytoplasmic fluid and the analytical velocity field around the macromolecular chain is obtained by solving the reduced nonlinear momentum equation using homotopy technique. The entropy generation by the fluid internal friction is calculated and incorporated into the entropic elasticity based 8-chain constitutive relations. Numerical examples showed strengthening behavior of cells in response to externally applied mechanical stimuli. The spatial… More >

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K. Y. Volokh^*
Molecular & Cellular Biomechanics, Vol.8, No.3, pp. 195-214, 2011, DOI:10.3970/mcb.2011.008.195
Abstract All models are wrong, but some are useful. This famous saying mirrors the situation in cell mechanics as well. It looks like no particular model of the cell deformability can be unconditionally preferred over others and different models reveal different aspects of the mechanical behavior of living cells. The purpose of the present work is to discuss the so-called tensegrity models of the cell cytoskeleton. It seems that the role of the cytoskeleton in the overall mechanical response of the cell was not appreciated until Donald Ingber put a strong emphasis on it. It was fortunate that Ingber linked the… More >

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Tianxiang Su^∗, Prashant K. Purohit^∗,†
Molecular & Cellular Biomechanics, Vol.8, No.3, pp. 215-232, 2011, DOI:10.3970/mcb.2011.008.215
Abstract Filaments under distributed loads are common in biological systems. In this paper, we study the thermo-mechanical properties of an extensible thermally fluctuating elastic filament under distributed forces. The ground state of the filament is solved first, followed by an investigation of the thermal fluctuations around the ground state. We first consider a special case where the tangential component of the distributed force t is uniform along the filament. For the force-extension relation in this case, we show that the filament is equivalent to one under end-to-end applied force F=tL0/2 where L0 is the length of the filament. To study the… More >

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Di Pan^*, Yuhua Song^∗,†
Molecular & Cellular Biomechanics, Vol.8, No.3, pp. 233-252, 2011, DOI:10.3970/mcb.2011.008.233
Abstract Cytoskeletal restraints affect force-regulated integrin function in cell adhesion. However, the structural and molecular basis underlying the effect of cytoskeletal restraints on b1 integrin binding to fibronectin is still largely unknown. In this study, we used steered molecular dynamics simulations to investigate the changes in glycosylated b1 integrin-fibronectin binding and in conformation and structure of the glycosylated b1 I-like domain-FN-III9 - 10 complex caused by altered restraints applied to b1 I-like domain. The results revealed that imposition of the increased constraints on b1 integrin increased resistance to force-induced dissociation of the b1 I-like domain-fibronectin complex. Specifically, the increased constraints enhanced… More >

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