A.L. Brock, D.E. Ingber¹

Molecular & Cellular Biomechanics, Vol.2, No.3, pp. 135-144, 2005, DOI:10.3970/mcb.2005.002.135

Abstract The direction in which cells extend new motile processes, such as lamellipodia and filopodia, can be controlled by altering the geometry of extracellular matrix adhesive islands on which individual cells are cultured, thereby altering mechanical interactions between cells and the adhesive substrate [Parker (2002)]. Here we specifically investigate the intracellular molecular signals that mediate the mechanism by which cells selectively extend these processes from the corners of polygonal-shaped adhesive islands. Constitutive activation of the small GTPase Rac within cells cultured on square-shaped islands of fibronectin resulted in the elimination of preferential extension from corners. This… More >

V.V. Mykhas’kiv¹, O.I. Stepanyuk²

CMES-Computer Modeling in Engineering & Sciences, Vol.10, No.1, pp. 45-64, 2005, DOI:10.3970/cmes.2005.010.045

Abstract The 3D elastostatic problem for an infinite remotely loaded matrix containing a finite number of arbitrarily located rigid disk-inclusions and plane cracks is solved by the boundary integral equation (BIE) method. Its boundary integral formulation is achieved by the superposition principle with the subsequent integral representations of superposition terms through surface integrals, which should satisfy the displacement linearity conditions in the inclusion domains and load-free conditions in the crack domains. The subtraction technique in the conjunction with mapping technique under taking into account the structure of the solution at the edges of inhomogeneities is applied More >

Tanmay Lele^1,1, Philmo Oh^1,1, Jeffrey A. Nickerson^1,1,2,2, Donald E. Ingber^1,1,3,3

Molecular & Cellular Biomechanics, Vol.1, No.3, pp. 181-190, 2004, DOI:10.3970/mcb.2004.001.181

Abstract The estimation of binding constants and diffusion coefficients of molecules that associate with insoluble molecular scaffolds inside living cells and nuclei has been facilitated by the use of Fluorescence Recovery after Photobleaching (FRAP) in conjunction with mathematical modeling. A critical feature unique to FRAP experiments that has been overlooked by past mathematical treatments is the existence of an `equilibrium constraint': local dynamic equilibrium is not disturbed because photobleaching does not functionally destroy molecules, and hence binding-unbinding proceeds at equilibrium rates. Here we describe an improved mathematical formulation under the equilibrium constraint which provides a more… More >

H.J. Bohm¨ ¹, W. Han^1,2, A. Eckschlager^1,3

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.1, pp. 5-20, 2004, DOI:10.3970/cmes.2004.005.005

Abstract Three-dimensional periodic micromechanical models are used for studying the mechanical behavior of discontinuously reinforced ductile matrix composites. The models are based on unit cells that contain a number of randomly positioned and, where applicable, randomly oriented spherical, spheroidal or cylindrical reinforcements. The Finite Element method is used to resolve the microscale stress and strain fields and to predict the homogenized responses under overall uniaxial tensile loading in the elastic and elastoplastic regimes. Periodicity boundary conditions are employed in the analyses.\\ The main emphasis of the contribution is put on studying the microscale stresses in the More >

T. Tsangaris¹, Y.–S. Smyrlis^{1, 2}, A. Karageorghis^{1, 2}

CMC-Computers, Materials & Continua, Vol.1, No.3, pp. 245-258, 2004, DOI:10.3970/cmc.2004.001.245

Abstract The Method of Fundamental Solutions (MFS) is a boundary-type method for the solution of certain elliptic boundary value problems. In this work, we develop an efficient matrix decomposition MFS algorithm for the solution of biharmonic problems in annular domains. The circulant structure of the matrices involved in the MFS discretization is exploited by using Fast Fourier Transforms. The algorithm is tested numerically on several examples. More >

Norma Risler, Claudia Castro, Montserrat Cruzado, Susana González, Roberto Miatello

BIOCELL, Vol.27, No.2, pp. 189-196, 2003, DOI:10.32604/biocell.2003.27.189

Abstract Remodeling of large and small arteries contributes to the development and complications of hypertension. Artery structural changes in chronic sustained hypertension include vascular smooth muscle cells (VSMC) proliferation and extracellular matrix (ECM) modifications. Extracellular constituents such as proteoglycans (PGs), may modulate vascular stiffness and VSMC growth and differentiation. We examined the effect of growth factors on secreted and membrane-bound PGs synthesis by cultured aortic smooth muscle cells (SMC) from 12- to 14- week-old spontaneously hypertensive rats (SHR) and age-matched Wistar rats. After stimulation with platelet-derived growth factor (PDGF-BB), 10% fetal calf serum (FCS) or 0.1%… More >

Gerhard Klimeck^1,2, Fabiano Oyafuso², Timothy B. Boykin³, R. Chris Bowen², Paul von Allmen⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.5, pp. 601-642, 2002, DOI:10.3970/cmes.2002.003.601

Abstract Material layers with a thickness of a few nanometers are common-place in today's semiconductor devices. Before long, device fabrication methods will reach a point at which the other two device dimensions are scaled down to few tens of nanometers. The total atom count in such deca-nano devices is reduced to a few million. Only a small finite number of "free'' electrons will operate such nano-scale devices due to quantized electron energies and electron charge. This work demonstrates that the simulation of electronic structure and electron transport on these length scales must not only be fundamentally… More >