Kittisak Koombua^*, Ramana M. Pidaparti^∗,†,‡, P. Worth Longest^∗,‡, Kevin R. Ward^‡,§

Molecular & Cellular Biomechanics, Vol.6, No.4, pp. 203-216, 2009, DOI:10.3970/mcb.2009.006.203

Abstract Without proper knowledge of mechanical ventilation effects, physicians can aggravate an existing lung injury. A better understanding of the interaction between airflow and airway tissue during mechanical ventilation will be helpful to physicians so that they can provide appropriate ventilator parameters for intubated patients. In this study, a computational model incorporating the interactions between airflow and airway walls was developed to investigate the effects of airway tissue flexibility on airway pressure and stress. Two flow rates, 30 and 60 l/min, from mechanical ventilation were considered. The transient waveform was active inhalation with a constant flow rate and passive exhalation. Results… More >

Yanan Wang^∗, Qing-Hua Qin^∗, Shankar Kalyanasundaram^∗

Molecular & Cellular Biomechanics, Vol.6, No.2, pp. 101-112, 2009, DOI:10.3970/mcb.2009.006.101

Abstract A mathematical model is developed for simulating anabolic behaviour of bone affected by Parathyroid Hormone (PTH) in this paper. The model incorporates a new understanding on the interaction of PTH and other factors with the RANK-RANKL-OPG pathway into bone remodelling, which is able to simulate anabolic actions of bone induced by PTH at cellular level. The RANK-RANKL-OPG pathway together with the dual action of TGF-$\beta$, which represent the core of coupling behaviour between osteoblasts and osteoclasts which are two cell types specialising in the maintenance of bone integrity, are widely considered essential for the regulation of bone remodelling at cellular… More >

Hai-Chao Han^†

Molecular & Cellular Biomechanics, Vol.6, No.2, pp. 93-100, 2009, DOI:10.3970/mcb.2009.006.093

Abstract Though tortuosity and kinking are often observed in various arteries and arterioles, little is known about the underlying mechanisms. This paper presents a biomechanical analysis of bent buckling in long arterial segments with a small initial curvature using a thick-walled elastic cylindrical arterial model. The critical buckling pressure was established as a function of wall stiffness, wall dimensions, and the axial tension (or axial stretch ratio). The effects of both wall dimensions and axial stretch ratio on the critical pressure, as well as the thin-walled approximation were discussed. The buckling equation sheds light on the biomechanical mechanism of artery tortuosity… More >

Weijuan Yao^*, Lanping Amy Sung^†

Molecular & Cellular Biomechanics, Vol.6, No.1, pp. 71-82, 2009, DOI:10.3970/mcb.2009.006.071

Abstract Erythrocyte tropomodulin (E-Tmod) is a tropomyosin-binding and actin capping protein at the point end of the filaments. It is part of a molecular ruler that plays an important role in generating short actin protofilaments critical for the integrity of the cell membrane. Here, with the use of \textit {E-Tmod+/lacZ} mice, we demonstrated a specific E-Tmod expression in horizontal cells (HCs) in the retina, and analyzed the stress-strain relationship of HCs, vertically oriented neurons, and retinal ganglial cells (RGC) under normal and high intraocular pressure (IOP). Since their dendrites are oriented laterally in a plane and form most complicated synapses with… More >

Tak-Sing Wong^*, Branden Brough^†, Chih-Ming Ho^∗,‡

Molecular & Cellular Biomechanics, Vol.6, No.1, pp. 1-56, 2009, DOI:10.3970/mcb.2009.006.001

Abstract Mimicking nature's approach in creating devices with similar functional complexity is one of the ultimate goals of scientists and engineers. The remarkable elegance of these naturally evolved structures originates from bottom-up self-assembly processes. The seamless integration of top-down fabrication and bottom-up synthesis is the challenge for achieving intricate artificial systems. In this paper, technologies necessary for guided bottom-up assembly such as molecular manipulation, molecular binding, and the self assembling of molecules will be reviewed. In addition, the current progress of synthesizing mechanical devices through top-down and bottom-up approaches will be discussed. 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 >

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 >

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 >

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 >

Geert W. Schmid-Schönbein^*

Molecular & Cellular Biomechanics, Vol.5, No.2, pp. 83-96, 2008, DOI:10.3970/mcb.2008.005.083

Abstract Increasing evidence suggests that most cardiovascular diseases, tumors and other ailments are associated with an inflammatory cascade. The inflammation is accompanied by activation of cells in the circulation and fundamental changes in the mechanics of the microcirculation, expression of pro-inflammatory genes and downregulation of anti-inflammatory genes, attachment of leukocytes to the endothelium, elevated permeability of the endothelium, and many other events. The evidence has opened great opportunities for medicine to develop new anti-inflammatory interventions. But it also raises a fundamental question: What is the origin of inflammation? I will discuss a basic series of studies that was designed to explore… More >