D.D. D’Lima^*, P.C. Chen^†, O. Kessler^‡, H.R. Hoenecke^*, C.W. Colwell Jr.^∗§

Molecular & Cellular Biomechanics, Vol.8, No.2, pp. 123-134, 2011, DOI:10.3970/mcb.2011.008.123

Abstract The menisci are important biomechanical components of the knee. We developed and validated a finite element model of meniscal replacement to assess the effect of surgical fixation technique on contact behavior and knee stability. The geometry of femoral and tibial articular cartilage and menisci was segmented from magnetic resonance images of a normal cadaver knee using MIMICS (Materialise, Leuven, Belgium). A finite element mesh was generated using HyperWorks (Altair Inc, Santa Ana, CA). A finite element solver (Abaqus v6.9, Simulia, Providence, RI) was used to compute contact area and stresses under axial loading and to… More >

Wei Huang^∗,†, Qinlian Zhou^†,‡, Jian Gao^‡, R. T. Yen^‡,§,¶

Molecular & Cellular Biomechanics, Vol.8, No.2, pp. 105-122, 2011, DOI:10.3970/mcb.2011.008.105

Abstract A continuum model was introduced to analyze the pressure-flow relationship for steady flow in human pulmonary circulation. The continuum approach was based on the principles of continuum mechanics in conjunction with detailed measurement of vascular geometry, vascular elasticity and blood rheology. The pulmonary arteries and veins were considered as elastic tubes and the "fifth-power law" was used to describe the pressure-flow relationship. For pulmonary capillaries, the "sheet-flow" theory was employed and the pressure-flow relationship was represented by the "fourth-power law". In this paper, the pressure-flow relationship for the whole pulmonary circulation and the longitudinal pressure More >

Wei Huang^∗,†, Yi Wah Mak^*, Peter C. Y. Chen^‡§

Molecular & Cellular Biomechanics, Vol.8, No.2, pp. 91-104, 2011, DOI:10.3970/mcb.2011.008.091

Abstract A molecular configuration tensor Pij was introduced to analyze the distribution of fibrous proteins in vascular cells for studying cells and tissues biomechanics. We have used this technique to study the biomechanics of vascular remodeling in response to the changes of blood pressure and flow. In this paper, the remodeling of the geometrical arrangement of F-actin fibers in the smooth muscle cells in rat's pulmonary arteries in hypoxic hypertension was studied. The rats were exposed to a hypoxia condition of 10% for 0, 2, 12, and 24 hr at sea level. Remodeling of blood vessels… More >

Biyue Liu^∗, Dalin Tang^†

Molecular & Cellular Biomechanics, Vol.8, No.1, pp. 73-90, 2011, DOI:10.3970/mcb.2011.008.073

Abstract The objective of this work is to investigate the effect of non-Newtonian properties of blood on the wall shear stress (WSS) in atherosclerotic coronary arteries using both Newtonian and non-Newtonian models. Numerical simulations were performed to examine how the spatial and temporal WSS distributions are influenced by the stenosis size, blood viscosity, and flow rate. The computational results demonstrated that blood viscosity properties had considerable effect on the magnitude of the WSS, especially where disturbed flow was observed. The WSS distribution is highly non-uniform both temporally and spatially, especially in the stenotic region. The maximum More >

Hiroaki Yoshida, Mitsunori Tada^†, Masaaki Mochimaru^†

Molecular & Cellular Biomechanics, Vol.8, No.1, pp. 61-72, 2011, DOI:10.3970/mcb.2011.008.061

Abstract Since the tactile perception detects skin deformation due to the contact of an object, it is important to understand contact mechanics, especially, frictional behavior of the human fingertip. The coefficient of friction is recently modeled as a function of the applied normal load in which case the traditional Coulomb's law does not provide a description for the skin surface. When a surface is a rubber-like material, the frictional behavior follows the frictional law of the rubber-like material. Therefore, we developed a three-dimensional Finite Element model of the fingertip and analyzed frictional behavior based on the… More >

Min Zhang^∗, Fa-Ming Chen^†, Yong-Jin Chen^∗,‡, Shun Wu^∗, Xin Lv^∗, Rui-Ni Zhao^∗

Molecular & Cellular Biomechanics, Vol.8, No.1, pp. 43-60, 2011, DOI:10.3970/mcb.2011.008.043

Abstract To investigate the role of mechanical pressure on cartilage thickness and type II collagen synthesis, and the role of G protein in that process, in vitro organ culture of mandibular cartilage was adopted in this study. A hydraulic pressure-controlled cellular strain unit was used to apply hydrostatic pressurization to explant cultures. The explants were compressed by different pressure values (0 kPa, 100 kPa, and 300 kPa) after pretreatment with or without a selective and direct antagonist (NF023) for the G proteins. After 4, 8 and 12 h of cell culture under each pressure condition, histological… More >

Ashish Das^∗, William M. Gottliebson^†,‡, Madhura Karve^∗, Rupak Banerjee^∗,§,¶

Molecular & Cellular Biomechanics, Vol.8, No.1, pp. 21-42, 2011, DOI:10.3970/mcb.2011.008.021

Abstract Right ventricular (RV) enlargement and pulmonary valve insufficiency (PI) are well-known, unavoidable long term sequelae encountered by patients who undergo tetralogy of Fallot (TOF) surgery. Despite their lifelong need for cardiac surveillance and occasional re-intervention, there is a paucity of numerical data characterizing blood flows in their pulmonary arteries (PA). Specifically, although PA regurgitation is well-known to be ubiquitously present in adult repaired TOF (rTOF) patients yet, there have been only limited numerical studies to fully characterize this process. The few studies available have utilized idealized, simplistic geometric models or overly simplistic boundary conditions that… More >

Bhaskar Chandra Konala^∗, Ashish Das^∗, Rupak K Banerjee^∗,†

Molecular & Cellular Biomechanics, Vol.8, No.1, pp. 1-20, 2011, DOI:10.3970/mcb.2011.008.001

Abstract Hemodynamic endpoints such as flow and pressure drop are often measured during angioplasty procedures to determine the functional severity of a coronary artery stenosis. There is a lack of knowledge regarding the influence of compliance of the arterial wall-stenosis on the pressure drop under hyperemic flows across coronary lesions. This study evaluates the influence in flow and pressure drop caused by variation in arterial-stenosis compliance for a wide range of stenosis severities. The flow and pressure drop were evaluated for three different severities of stenosis and tested for limiting scenarios of compliant models. The Mooney-Rivlin… More >

G. Kosec¹, B. Šarler^1,2

CMC-Computers, Materials & Continua, Vol.26, No.3, pp. 227-254, 2011, DOI:10.3970/cmc.2011.026.227

Abstract This paper introduces an effective H-adaptive upgrade to solution of the transport phenomena by the novel Local Radial Basis Function Collocation Method (LRBFCM). The transport variable is represented on overlapping 5-noded influence-domains through collocation by using multiquadrics Radial Basis Functions (RBF). The involved first and second derivatives of the variable are calculated from the respective derivatives of the RBFs. The transport equation is solved through explicit time stepping. The H-adaptive upgrade includes refinement/derefinement of one to four nodes to/from the vicinity of the reference node. The number of the nodes added or removed depends on… More >

W. Zhang¹, X. Han^1,2, J. Liu¹, Z. H. Tan¹

CMC-Computers, Materials & Continua, Vol.26, No.3, pp. 201-226, 2011, DOI:10.3970/cmc.2011.026.201

Abstract The uncertainty inverse problems with insufficiency and imprecision in the input and/or output parameters are widely existing and unsolved in the practical engineering. The insufficiency refers to the partly known parameters in the input and/or output, and the imprecision refers to the measurement errors of these ones. In this paper, a combined method is proposed to deal with such problems. In this method, the imprecision of these known parameters can be described by probability distribution with a certain mean value and variance. Sensitive matrix method is first used to transform the insufficient formulation in the More >