D.-A. An-Vo, N. Mai-Duy, T. Tran-Cong

The International Conference on Computational & Experimental Engineering and Sciences, Vol.16, No.3, pp. 87-88, 2011, DOI:10.3970/icces.2011.016.087

Abstract In this paper, we develop a control-volume technique based on 2-node integrated-radial-basis-function elements (IRBFEs) for the numerical solution of steady incompressible flows governed by the stream function-vorticity formulation. The fluid domain is discretised by a Cartesian grid from which non-overlapping rectangular control- volumes are formed. Line integrals arising from the integration of the diffusion and convection terms over control volumes are evaluated using the middle-point rule. The convection term is effectively treated by the upwind scheme with deferred correction strategy. Instead of using conventional low-order polynomials, all physical quantities at the interfaces are presently estimated by means of 2-node IRBFEs.… More >

N. Mai-Duy¹, T. Tran-Cong¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.14, No.2, pp. 51-56, 2010, DOI:10.3970/icces.2010.014.051

Abstract This paper presents a preconditioning scheme to improve the condition number of integrated radial-basis-function (RBF) matrices in solving large-scale 2D elliptic problems. The problem domain is discretised using a Cartesian grid, over which integrated RBF networks are employed to represent the field variable. The present preconditioner is constructed from 1D integrated RBF networks along grid lines. Test problems defined on rectangular and non-rectangular domains are employed to study the performance of the scheme. More >

Lilan Gao^1,2,*, Qingxian Yuan^1,2, Ruixin Li^3,*, Lei Chen^1,2, Chunqiu Zhang^1,2, Xizheng Zhang^1,2

Molecular & Cellular Biomechanics, Vol.15, No.2, pp. 85-98, 2018, DOI: 10.3970/mcb.2018.00329

Abstract Silk fibroin-typeⅡcollagen scaffold was made by 3D printing technique and freeze-drying method, and its mechanical properties were studied by experiments and theoretical prediction. The results show that the three-dimensional silk fibroin-typeⅡ collagen scaffold has good porosity and water absorption, which is (89.3%+3.26%) and (824.09%+93.05%), respectively. With the given strain value, the stress of scaffold decreases rapidly firstly and then tends to be stable during the stress relaxation. Both initial and instantaneous stresses increase with increase of applied strain value. The creep strains of scaffold with different stress levels show the two stages: the rapidly increasing stage and the second stable… More >

Yongren Wu^∗, Sarah Cisewski^∗, Barton L. Sachs^†, Hai Yao^∗,†,‡

Molecular & Cellular Biomechanics, Vol.10, No.2, pp. 159-182, 2013, DOI:10.3970/mcb.2013.010.159

Abstract This study examines the effects of cartilage endplate (CEP) calcification and the injection of intervertebral disc (IVD) cells on the nutrition distributions inside the human IVD under physiological loading conditions using multiphasic finite element modeling. The human disc was modeled as an inhomogeneous mixture consisting of a charged elastic solid, water, ions (Na⁺ and Cl⁻), and nutrient solute(oxygen,glucose and lactate) phases. The effect of the endplate calcification was simulated by a reduction of the tissue porosity (i.e., water volume faction) from 0.60 to 0.48. The effect of cell injection was simulated by increasing the cell density in the nucleus pulposus… More >

Wangping Duan^∗, Lei Wei^†, Juntao Zhang^∗, Yongzhuang Hao^∗, Chunjiang Li^∗, Hao Li^∗, Qi Li^∗, Quanyou Zhang^‡, Weiyi Chen^‡, Xiaochun Wei^∗,§

Molecular & Cellular Biomechanics, Vol.8, No.4, pp. 253-274, 2011, DOI:10.3970/mcb.2011.008.253

Abstract The cytoskeleton network is believed to play an important role in the biomechanical properties of the chondrocyte. Ours and other laboratories have demonstrated that chondrocytes exhibit a viscoelastic solid creep behavior in vitro and that viscoelastic properties decrease in osteoarthritic chondrocytes. In this study, we aimed to understand whether the alteration of viscoelastic properties is associated with changes in cytoskeleton components of ageing chondrocytes from rabbit knee articular cartilage. Three age groups were used for this study: young (2-months-old, N=23), adult (8-months-old, N=23), and old (31-months-old, N=23) rabbit groups. Cartilage structure and proteoglycan and type II collagen content were determined… More >

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 assess stability (reaction force generated… 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 sections of the explants were… More >

Rami K Korhonen^∗,†, Sang-Kuy Han^‡, Walter Herzog^‡

Molecular & Cellular Biomechanics, Vol.7, No.3, pp. 125-134, 2010, DOI:10.3970/mcb.2010.007.125

Abstract Changes in the osmotic environment cause changes in volume of isolated cells and cells in tissue explants, and the osmotic environment becomes hypotonic in cartilage diseases such as osteoarthritis (OA). However, it is not known how cells respond to a hypotonic osmotic challenge when situated in the fully intact articular cartilage.
A confocal laser scanning microscope was used to image chondrocytes of intact rabbit patellae in an isotonic (300 mOsm) and hypotonic (172 mOsm) immersion medium. Cell volumes were calculated before and 5, 15, 60, 120 and 240 minutes after the change in saline concentration. Local tissue strains and swelling… More >

Q Wang^*, YP Zheng^∗,†, HJ Niu^∗,‡

Molecular & Cellular Biomechanics, Vol.7, No.1, pp. 45-58, 2010, DOI:10.3970/mcb.2010.007.045

Abstract This study aims to obtain osmosis-induced swelling strains of normal and proteoglycan (PG) depleted articular cartilage using an ultrasound system and to investigate the changes in its mechanical properties due to the PG depletion using a layered triphasic model. The swelling strains of 20 cylindrical cartilage-bone samples collected from different bovine patellae were induced by decreasing the concentration of bath saline and monitored by the ultrasound system. The samples were subsequently digested by a trypsin solution for approximately 20 min to deplete proteoglycans, and the swelling behaviors of the digested samples were measured again. The bi-layered triphasic model proposed in… More >

Fan Song^*

Molecular & Cellular Biomechanics, Vol.7, No.1, pp. 13-24, 2010, DOI:10.3970/mcb.2010.007.013

Abstract The electrostatic interaction effects including the interaction potential, force and torque between the neighboring chondroitin sulfate glycosaminoglycan (CS-GAG) molecular chains in the bottle brush conformation of proteoglycan aggrecan are obtained as the functions of the minimum separation distance and the mutual angle between the molecular chains based on an asymptotic solution of the Poisson-Boltzmann equation that the CS-GAGs satisfy under the normal physiological conditions of articular cartilage. The present study indicates that the electrostatic interactions are not only associated intimately with the separation distance and the mutual angle, which are shown as purely exponential in separation distance and decrease with… More >