G. Lasko^∗, I. Schäfer^∗, Z. Burghard^†, J. Bill^†, S. Schmauder^∗, U. Weber^∗, D. Galler^‡

Molecular & Cellular Biomechanics, Vol.10, No.1, pp. 27-42, 2013, DOI:10.3970/mcb.2013.010.027

Abstract Owing to the apparent simple morphology and peculiar properties, nacre, an iridescent layer, coating of the inner part of mollusk shells, has attracted considerable attention of biologists, material scientists and engineers. The basic structural motif in nacre is the assembly of oriented plate-like aragonite crystals with a ’brick’ (CaCO₃ crystals) and ’mortar’ (macromolecular components like proteins) organization. Many scientific researchers recognize that such structures are associated with the excellent mechanical properties of nacre and biomimetic strategies have been proposed to produce new layered nanocomposites. During the past years, increasing efforts have been devoted towards exploiting nacre’s structural design principle in… More >

S.J. Mousavi^∗, M.H. Doweidar^∗,†, M. Doblaré^∗

Molecular & Cellular Biomechanics, Vol.10, No.1, pp. 1-25, 2013, DOI:10.3970/mcb.2013.010.001

Abstract Although there are several computational models that explain the trajectory that cells take during migration, till now little attention has been paid to the integration of the cell migration in a multi-signaling system. With that aim, a generalized model of cell migration and cell-cell interaction under multisignal environments is presented herein. In this work we investigate the spatio-temporal cell-cell interaction problem induced by mechano-chemo-thermotactic cues. It is assumed that formation of a new focal adhesion generates traction forces proportional to the stresses transmitted by the cell to the extracellular matrix. The cell velocity and polarization direction are calculated based on… More >

Hui Han^∗, David C. C. Lam^†, Wei Huang^†,‡

Molecular & Cellular Biomechanics, Vol.9, No.4, pp. 295-308, 2012, DOI:10.3970/mcb.2012.009.295

Abstract The objective of our study was to study the effect of danshen, a Chinese herbal medicine known to prevent hypertension, on the zero-stress state of rat's abdominal aorta. The zero-stress state of a blood vessel represents the release of residual stress on the vessel wall, and is the basic configuration of blood vessel affected solely by intrinsic parameters. At the in vivo state, the rat's abdominal aorta was subjected to blood pressure and flow and longitudinal stress. After dissecting from the abdominal aorta, the aortic specimens were cut into small rings at no-load state, in which the internal pressure, external… More >

Xibin Yang^*, Rui Li^†,‡, Jianfeng Zhu^*, Daxi Xiong^*

Molecular & Cellular Biomechanics, Vol.9, No.4, pp. 285-294, 2012, DOI:10.3970/mcb.2012.009.285

Abstract A new type of optocoupler applied to medical lighting system is proposed, and the principle, Etendue and design process is introduced. With the help of Tracrpro, modeling and simulation of the optocoupler is conducted and the parameters are optimized. Analysis of factors affecting the energy coupling efficiency is done. With a view towards the development of Ultra High Brightness Light Emitting Diodes (UHB-LEDs), which play an important role a new sources of lighting in various biomedical devices, including those used in diagnosis and treatment, a series of simulations are executed and a variety of solutions are achieved. According to simulation… More >

Wei Huang^∗, Jun Shi^†, R. T. Yen^†,‡

Molecular & Cellular Biomechanics, Vol.9, No.4, pp. 269-284, 2012, DOI:10.3970/mcb.2012.009.269

Abstract The objective of our study was to develop a computing program for computing the transit time frequency distributions of red blood cell in human pulmonary circulation, based on our anatomic and elasticity data of blood vessels in human lung. A stochastic simulation model was introduced to simulate blood flow in human pulmonary circulation. In the stochastic simulation model, the connectivity data of pulmonary blood vessels in human lung was converted into a probability matrix. Based on this model, the transit time of red blood cell in human pulmonary circulation and the output blood pressure were studied. Additionally, the stochastic simulation… More >

Match W L Ko^∗, Leo K K Leung^∗, David C C Lam^∗,†

Molecular & Cellular Biomechanics, Vol.9, No.4, pp. 251-268, 2012, DOI:10.3970/mcb.2012.009.251

Abstract Inter-individual differences in corneal properties are ignored in existing methods for measuring intraocular pressure IOP, a primary parameter used in screening and monitoring of glaucoma. The differences in the corneal stiffness between individuals can be more than double and this difference would lead to IOP measurement errors up to 10 mmHg. In this study, an instrumented partial-contact indentation measurement and analysis method that can account for inter-individual corneal difference in stiffness is developed. The method was tested on 12 porcine eyes ex vivo and 7 rabbit eyes in vivo, and the results were compared to the controlled IOPs to determine… More >

Sandra Deitch^∗, Bruce Z. Gao^†, Delphine Dean^‡

Molecular & Cellular Biomechanics, Vol.9, No.3, pp. 227-250, 2012, DOI:10.3970/mcb.2012.009.227

Abstract Cardiomyocyte phenotype changes significantly in 2D culture systems depending on the substrate composition and organization. Given the variety of substrates that are used both for basic cardiac cell culture studies and for regenerative medicine applications, there is a critical need to understand how the different matrices influence cardiac cell mechanics. In the current study, the mechanical properties of neonatal rat cardiomyocytes cultured in a subconfluent layer upon aligned and unaligned collagen and fibronectin matrices were assessed over a two week period using atomic force microscopy. The elastic modulus was estimated by fitting the Hertz model to force curve data and… More >

Yongjie Zhang^∗, Yiming Jing^∗, Xinghua Liang^∗, Guoliang Xu^†, Lei Dong^‡

Molecular & Cellular Biomechanics, Vol.9, No.3, pp. 213-226, 2012, DOI:10.3970/mcb.2012.009.213

Abstract A greyscale-based fully automatic deformable image registration algorithm, based on an optical flow method together with geometric smoothing, is developed for dynamic lung modeling and tumor tracking. In our computational processing pipeline, the input data is a set of 4D CT images with 10 phases. The triangle mesh of the lung model is directly extracted from the more stable exhale phase (Phase 5). In addition, we represent the lung surface model in 3D volumetric format by applying a signed distance function and then generate tetrahedral meshes. Our registration algorithm works for both triangle and tetrahedral meshes. In CT images, the… More >

G. Sciumè^∗,†, S.E. Shelton^‡, W.G. Gray^‡, C.T. Miller^‡, F. Hussain^§,¶, M. Ferrari^¶, P. Decuzzi^¶, B.A. Schrefler^∗,¶

Molecular & Cellular Biomechanics, Vol.9, No.3, pp. 193-212, 2012, DOI:10.3970/mcb.2012.009.193

Abstract Multiphase porous media mechanics is used for modeling tumor growth, using governing equations obtained via the Thermodynamically Constrained Averaging Theory (TCAT). This approach incorporates the interaction of more phases than legacy tumor growth models. The tumor is treated as a multiphase system composed of an extracellular matrix, tumor cells which may become necrotic depending on nutrient level and pressure, healthy cells and an interstitial fluid which transports nutrients. The governing equations are numerically solved within a Finite Element framework for predicting the growth rate of the tumor mass, and of its individual components, as a function of the initial tumor-to-healthy… More >

Walter Herzog^∗, Tim Leonard^†, Venus Joumaa^‡, Michael DuVall^§, Appaji Panchangam^¶

Molecular & Cellular Biomechanics, Vol.9, No.3, pp. 175-192, 2012, DOI:10.3970/mcb.2012.009.175

Abstract Ever since the 1950s, muscle force regulation has been associated with the cross-bridge interactions between the two contractile filaments, actin and myosin. This gave rise to what is referred to as the "two-filament sarcomere model". This model does not predict eccentric muscle contractions well, produces instability of myosin alignment and force production on the descending limb of the force-length relationship, and cannot account for the vastly decreased ATP requirements of actively stretched muscles. Over the past decade, we and others, identified that a third myofilament, titin, plays an important role in stabilizing the sarcomere and the myosin filament. Here, we… More >