Jie Wu^∗,†, Quan Long^‡, Shixiong Xu^*, Anwar R. Padhani^§, Yuping Jiang^¶

Molecular & Cellular Biomechanics, Vol.5, No.4, pp. 217-228, 2008, DOI:10.3970/mcb.2008.005.217

Abstract In this paper, a 3D mathematical model of tumour angiogenesis is developed, to generate a functional tumour vasculature for blood microcirculation. The model follows that of Anderson and Chaplain (1998) ^[1] with three exceptions: (a) extending the model from 2D to 3D, one arteriole and one venule is induced as two parent vessels to form an intact circulation network for blood flow; (b) generating networks able to penetrate into the tumour interior rather than the exterior only; (c) considering branching generations with different diameters, based on which three groups of vessels, such as arterioles, venules and capillaries are classified. The… More >

K.Y. Volokh ^*

Molecular & Cellular Biomechanics, Vol.5, No.3, pp. 207-216, 2008, DOI:10.3970/mcb.2008.005.207

Abstract One of the seminal contributions of Y.C. Fung to biomechanics of soft tissue is the introduction of the models of arterial deformation based on the exponential stored energy functions, which are successfully used in various applications. The Fung energy functions, however, explain behavior of intact arteries and do not include a description of arterial failure. The latter is done in the present work where Fung's model is enhanced with a failure description. The description is based on the introduction of a limiter for the stored energy -- the average energy of chemical bonds, which can be interpreted as a failure… More >

Benjamin L. Wong^*, Won C. Bae^*, Kenneth R. Gratz^*, Robert L. Sah^∗,†

Molecular & Cellular Biomechanics, Vol.5, No.3, pp. 197-206, 2008, DOI:10.3970/mcb.2008.005.197

Abstract During joint articulation, the biomechanical behavior of cartilage not only facilitates load-bearing and low-friction, but also provides regulatory cues to chondrocytes. Elucidation of cartilage kinematics under combined compression and shearing conditions clarifies these cues in health and disease. The objectives of this study were to elucidate the effects of lubricant, tissue degeneration, and stress relaxation duration on cartilage shear kinematics during articulation. Human osteochondral cores with normal and mildly degenerate surface structures were isolated. Paired blocks from each core were apposed, compressed, allowed to stress relax for 5 or 60 min, and shear tested with a micro-scale video microscopy system… More >

Benjamin A. Coppola^*, Jeffrey H. Omens^∗,†

Molecular & Cellular Biomechanics, Vol.5, No.3, pp. 183-196, 2008, DOI:10.3970/mcb.2008.005.183

Abstract It is well known that systolic wall thickening in the inner half of the left ventricular (LV) wall is of greater magnitude than predicted by myofiber contraction alone. Previous studies have related the deformation of the LV wall to the orientation of the laminar architecture. Using this method, wall thickening can be interpreted as the sum of contributions due to extension, thickening, and shearing of the laminar sheets. We hypothesized that the thickening mechanics of the ventricular wall are determined by the structural organization of the underlying tissue, and may not be influenced by factors such as loading and activation… More >

Vedula S.R.K.^*, Lim T.S.^†, Hunziker W.^‡, Lim C.T.^§

Molecular & Cellular Biomechanics, Vol.5, No.3, pp. 169-182, 2008, DOI:10.3970/mcb.2008.005.169

Abstract Intercellular adhesion molecules play an important role in regulating several cellular processes such as a proliferation, migration and differentiation. They also play an important role in regulating solute diffusion across monolayers of cells. The adhesion characteristics of several intercellular adhesion molecules have been studied using various biochemical assays. However, the advent of single molecule force spectroscopy as a powerful tool to analyze the kinetics and strength of protein interactions has provided us with an opportunity to investigate these interactions at the level of a single molecule. The study of interactions involving intercellular adhesion molecules has gained importance because of the… More >

Lai Yee Leung^*, Pamela J. VandeVord^∗,†, Alessandra Leonardi Dal Cengio^*, Cynthia Bir^*, King H. Yang^*, Albert I. King^*

Molecular & Cellular Biomechanics, Vol.5, No.3, pp. 155-168, 2008, DOI:10.3970/mcb.2008.005.155

Abstract Historically, blast overpressure is known to affect primarily gas-containing organs such as the lung and ear. More recent interests focus on its ability to cause damage to solid organs such as the brain, resulting in neurological disorders. Returning veterans exposed to blast but without external injuries are being diagnosed with mild traumatic brain injury (Warden 2006) and with cortical dysfunction (Cernak et al 1999). Decades of studies have been conducted to elucidate the effects of primary blast wave on the central nervous system. These studies were mostly concerned with systemic effects (Saljo et al 2000-2003; Kaur et al 1995-1997, 1999;… More >

Lihai Zhang^*, Bruce S. Gardiner^*, David W. Smith^*, Peter Pivonka^*, Alan Grodzinsky^†

Molecular & Cellular Biomechanics, Vol.5, No.2, pp. 133-154, 2008, DOI:10.3970/mcb.2008.005.133

Abstract Cartilage maintains its integrity in a hostile mechanical environment. This task is made more difficult because cartilage has no blood supply, and so nutrients and growth factors need to be transported greater distances than normal to reach cells several millimetres from the cartilage surface. The chondrocytes embedded within the extracellular matrix (ECM) are essential for maintaining the mechanical integrity of the ECM, through a balance of degradation and synthesis of collagen and proteoglycans. A chondrocyte senses various chemical and mechanical signals in its local microenvironment, responding by appropriate adaption of the local ECM. Clearly a 'systems understanding' of cartilage behaviour… More >

Gretchen J. McAuliffe^*, Jung Yun Chang^†, Raymond P. Glahn^‡, Michael L. Shuler^§

Molecular & Cellular Biomechanics, Vol.5, No.2, pp. 119-132, 2008, DOI:10.3970/mcb.2008.005.119

Abstract Microscale cell culture analogs (μCCAs) are used to study the metabolism and toxicity of a chemical or drug. These in vitro devices are physical replicas of physiologically based pharmacokinetic models that combine microfabrication and cell culture. The goal of this project is to add an independent GI tract μCCA to a multi-chamber chip μCCA representing the primary circulation. The GI tract μCCA consists of two chambers separated by a microporous membrane on which intestinal epithelial cells are cultured. Compounds of interest are pumped through the top chamber, allowing drug to be absorbed through the epithelial layer and circulated into the… More >

Hong Qian^*

Molecular & Cellular Biomechanics, Vol.5, No.2, pp. 107-118, 2008, DOI:10.3970/mcb.2008.005.107

Abstract At the molecular and cellular level, mechanics and chemistry are two aspects of the same macromolecular system. We present a bottom-up approach to such systems based on Kramers' diffusion theory of chemical reactions, the theory of polymer dynamics, and the recently developed models for molecular motors. Using muscle as an example, we develop a viscoelastic theory of muscle in terms of an simple equation for single motor protein movement. Both A.V. Hill's contractile component and A.F. Huxley's equation of sliding-filament motion are shown to be special cases of the general viscoelastic theory of the active material. Some disparity between the… More >

Shaohua Chen^*

Molecular & Cellular Biomechanics, Vol.5, No.2, pp. 97-106, 2008, DOI:10.3970/mcb.2008.005.097

Abstract Recently, contact mechanics has been widely used to get some understanding of the biological adhesion mechanisms, such as cell-cell adhesion, insects' adhesion and locomotion. JKR theory is usually adopted as a basis, in which the interaction of molecules is considered in contrast to the classical Hertz solution. In this paper, two problems are summarized, which may give some insights to cells or bio-molecules sensitivity to environmental signals: (1) cell reorientation on a stretched substrate; (2) spontaneous detachment between cells or bio-molecules under the variation of environmental signals. The intention here is only to illustrate the possibilities that contact mechanics may… More >