Open Access

REVIEW

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 >

View

1220

Download

1207

Open Access

ARTICLE

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 >

View

1006

Download

721

Open Access

ARTICLE

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 >

View

1018

Download

844

Open Access

ARTICLE

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 >

View

1062

Download

896