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K. Y. Volokh^*, E. Y. S. Chao^†, M. Armand^‡
Molecular & Cellular Biomechanics, Vol.4, No.2, pp. 67-74, 2007, DOI:10.3970/mcb.2007.004.067
Abstract Information about the stress distribution on contact surfaces of adjacent bones is indispensable for analysis of arthritis, bone fracture and remodeling. Numerical solution of the contact problem based on the classical approaches of solid mechanics is sophisticated and time-consuming. However, the solution can be essentially simplified on the following physical grounds. The bone contact surfaces are covered with a layer of articular cartilage, which is a soft tissue as compared to the hard bone. The latter allows ignoring the bone compliance in analysis of the contact problem, i.e. rigid bones are considered to interact through… More >

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G.V. Norton^*, J.C. Novarini^†
Molecular & Cellular Biomechanics, Vol.4, No.2, pp. 75-86, 2007, DOI:10.3970/mcb.2007.004.075
Abstract Ultrasonic imaging in medical applications involves propagation and scattering of acoustic waves within and by biological tissues that are intrinsically dispersive. Analytical approaches for modeling propagation and scattering in inhomogeneous media are difficult and often require extremely simplifying approximations in order to achieve a solution. To avoid such approximations, the direct numerical solution of the wave equation via the method of finite differences offers the most direct tool, which takes into account diffraction and refraction. It also allows for detailed modeling of the real anatomic structure and combination/layering of tissues. In all cases the correct… More >

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Judith Su^∗, Xingyu Jiang^†, Roy Welsch^‡, George M. Whitesides^§, Peter T. C. So^¶
Molecular & Cellular Biomechanics, Vol.4, No.2, pp. 87-104, 2007, DOI:10.3970/mcb.2007.004.087
Abstract Interactions between the cell and the extracellular matrix regulate a variety of cellular properties and functions, including cellular rheology. In the present study of cellular adhesion, area was controlled by confining NIH 3T3 fibroblast cells to circular micropatterned islands of defined size. The shear moduli of cells adhering to islands of well defined geometry, as measured by magnetic microrheometry, was found to have a significantly lower variance than those of cells allowed to spread on unpatterned surfaces. We observe that the area of cellular adhesion influences shear modulus. Rheological measurements further indicate that cellular shear… More >

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Judith Su^∗, Ricardo R. Brau^†, Xingyu Jiang^‡, George M. Whitesides^§, Matthew J. Lang^¶, Peter T. C. So^||
Molecular & Cellular Biomechanics, Vol.4, No.2, pp. 105-118, 2007, DOI:10.3970/mcb.2007.004.105
Abstract During migration, asymmetrically polarized cells achieve motion by coordinating the protrusion and retraction of their leading and trailing edges, respectively. Although it is well known that local changes in the dynamics of actin cytoskeleton remodeling drive these processes, neither the cytoskeletal rheological properties of these migrating cells are well quantified nor is it understand how these rheological properties are regulated by underlying molecular processes. In this report, we have used soft lithography to create morphologically polarized cells in order to examine rheological differences between the front and rear zone of an NIH 3T3 cell posed More >

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