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  • Open Access

    ARTICLE

    Modeling Active Contraction and Relaxation of Left Ventricle Using Different Zero-load Diastole and Systole Geometries for Better Material Parameter Estimation and Stress/Strain Calculations

    Longling Fan1,§, Jing Yao2,§, Chun Yang3, Di Xu2, Dalin Tang1,4*

    Molecular & Cellular Biomechanics, Vol.13, No.1, pp. 33-55, 2016, DOI:10.3970/mcb.2016.013.044

    Abstract Modeling ventricle active contraction based on in vivo data is extremely challenging because of complex ventricle geometry, dynamic heart motion and active contraction where the reference geometry (zero-stress geometry) changes constantly. A new modeling approach using different diastole and systole zero-load geometries was introduced to handle the changing zero-load geometries for more accurate stress/strain calculations. Echo image data were acquired from 5 patients with infarction (Infarct Group) and 10 without (Non-Infarcted Group). Echo-based computational two-layer left ventricle models using one zero-load geometry (1G) and two zero-load geometries (2G) were constructed. Material parameter values in Mooney-Rivlin models were adjusted to match… More >

  • Open Access

    ARTICLE

    The Correlation Between Texture Features and Fibrous Cap Thickness of Lipid-Rich Atheroma Based on Optical Coherence Tomography Imaging

    Chunliu He1, Jiaqiu Wang2, Yuxiang Huang1, Tongjing Zhu1, Yuehong Miao1, Zhiyong Li1,2*

    Molecular & Cellular Biomechanics, Vol.13, No.1, pp. 23-36, 2016, DOI:10.3970/mcb.2016.013.027

    Abstract Fibrous cap thickness (FCT) is seen as critical to plaque vulnerability. Therefore, the development of automatic algorithms for the quantification of FCT is for estimating cardiovascular risk of patients. Intravascular optical coherence tomography (IVOCT) is currently the only in vivo imaging modality with which FCT, the critical component of plaque vulnerability, can be assessed accurately. This study was aimed to discussion the correlation between the texture features of OCT images and the FCT in lipid-rich atheroma. Methods: Firstly, a full automatic segmentation algorithm based on unsupervised fuzzy c means (FCM) clustering with geometric constrains was developed to segment the ROIs… More >

  • Open Access

    ARTICLE

    Non-Newtonian Blood Flow in Left Coronary Arteries with Varying Stenosis: A Comparative Study

    PoojaJhunjhunwala1, P.M. Padole2, S.B. Thombre3

    Molecular & Cellular Biomechanics, Vol.13, No.1, pp. 1-21, 2016, DOI:10.3970/mcb.2016.013.001

    Abstract This paper presents Computational fluid dynamic (CFD) analysis of blood flow in three different 3-D models of left coronary artery (LCA). A comparative study of flow parameters (pressure distribution, velocity distribution and wall shear stress) in each of the models is done for a non-Newtonian (Carreau) as well as the Newtonian nature of blood viscosity over a complete cardiac cycle. The difference between these two types of behavior of blood is studied for both transient and steady states of flow. Additionally, flow parameters are compared for steady and transient boundary conditions considering blood as non-Newtonian fluid. The study shows that… More >

  • Open Access

    ARTICLE

    Design of Orthopedic Plates and Its Modification Based on Feature

    He Kunjin1,2, Zou Zeyu1, Zhang Rongli1

    Molecular & Cellular Biomechanics, Vol.12, No.4, pp. 265-286, 2015, DOI:10.32604/mcb.2015.012.263

    Abstract To quickly construct the orthopedic plates and to conveniently edit it, a novel method for designing the plates is put forward based on feature idea and parameterization. Firstly, attached to the existing or repaired bone model, the region of interest (ROI) is selected as the abutted surface of orthopedic plate, and the ROI is reconstructed to form a CAD surface. Secondly, the CAD surface is to be defined as a surface feature (SF) and then some semantic parameters are configured for it. Lastly, the plate body is constructed through thickening, and some higher parameters are defined for it so as… More >

  • Open Access

    ARTICLE

    Enhanced External Counterpulsation Treatment May Intervene The Advanced Atherosclerotic Plaque Progression by Inducing The Variations of Mechanical Factors: A 3D FSI Study Based on in vivo Animal Experiment

    Jianhang Du1,2,3, Liang Wang4

    Molecular & Cellular Biomechanics, Vol.12, No.4, pp. 249-263, 2015, DOI:10.3970/mcb.2015.012.249

    Abstract Growing evidences suggest that long-term enhanced external counterpulsation (EECP) treatment can inhibit the initiation of atherosclerotic lesion by improving the hemodynamic environment in aortas. However, whether this kind procedure will intervene the progression of advanced atherosclerotic plaque remains elusive and causes great concern in its clinical application presently. In the current paper, a pilot study combining animal experiment and numerical simulation was conducted to investigate the acute mechanical stress variations during EECP intervention, and then to assess the possible chronic effects. An experimentally induced hypercholesterolemic porcine model was developed and the basic hemodynamic measurement was performed in vivo before and… More >

  • Open Access

    ARTICLE

    A Coupled Mathematical Model of Cell Migration, Vessel Cooption and Tumour Microenvironment during the Initiation of Micrometastases

    Yan Cai1,2,3, Jie Wu4, Zhiyong Li1,2

    Molecular & Cellular Biomechanics, Vol.12, No.4, pp. 231-248, 2015, DOI:10.3970/mcb.2015.012.231

    Abstract We propose a coupled mathematical model for the detailed quantitative analyses of initial microtumour and micrometastases formation by including cancer cell migration, host vessel cooption and changes in microenvironment. Migrating cells are included as a new phenotype to describe the migration behaviour of malignant tumour cells. Migration probability of a migrating cell is assumed to be influenced by local chemical microenvironment. Pre-existing vessel cooption and remodelling are introduced according to the local haemodynamical microenvironment, such as interstitial pressure and vessel wall permeability. After the tumour cells and tumour vessels distribution are updated, the chemical substances are coupled calculated with the… More >

  • Open Access

    ARTICLE

    Size-Dependent Diffusion of Dextrans in Excised Porcine Corneal Stroma

    Ajith Rajapaksha1,2, Michael Fink1, Brian A. Todd1

    Molecular & Cellular Biomechanics, Vol.12, No.3, pp. 215-230, 2015, DOI:10.3970/mcb.2015.012.215

    Abstract Delivery of therapeutic agents to the eye requires efficient transport through cellular and extracellular barriers. We evaluated the rate of diffusive transport in excised porcine corneal stroma using fluorescently labeled dextran molecules with hydrodynamic radii ranging from 1.3 to 34 nm. Fluorescence correlation spectroscopy (FCS) was used to measure diffusion coefficients of dextran molecules in the excised porcine corneal stroma. The preferential sensitivity of FCS to diffusion along two dimensions was used to differentially probe diffusion along the directions parallel to and perpendicular to the collagen lamellae of the corneal stroma. In order to develop an understanding of how size… More >

  • Open Access

    ARTICLE

    Evaluation of Mechanical and Chemical Stimulations on Osteocalcin and Runx2 Expression in Mesenchymal Stem Cells

    Maryam Jazayeri1, Mohammad Ali Shokrgozar1, Nooshin Haghighipour1,2, Reza Mahdian3, Mehdi Farrokhi1, Shahin Bonakdar1, FereshtehMirahmadi1, Tannaz Nourizadeh Abbariki

    Molecular & Cellular Biomechanics, Vol.12, No.3, pp. 197-213, 2015, DOI:10.3970/mcb.2015.012.197

    Abstract The osseous tissue repair and regeneration have great importance in orthopedic and maxillofacial surgery. Tissue engineering makes it possible to cure different tissue abnormalities using autologous grafts. It is now obvious that mechanical loading has essential role in directing cells to differentiation. In this study, the influence of cyclic uniaxial loading and its combination with chemical factors on expression of osteogenic markers was investigated. Rat bone marrow-derived stem cells were isolated and cultured. In one group cells were maintained in chemical induction medium. In another group cells were subjected to cyclic uniaxial strain with 3% amplitude and 0.3 Hz frequency… More >

  • Open Access

    REVIEW

    Overview: Mechanism and Control of a Prosthetic Arm

    Tushar Kulkarni1,2, Rashmi Uddanwadiker1

    Molecular & Cellular Biomechanics, Vol.12, No.3, pp. 147-195, 2015, DOI:10.3970/mcb.2015.012.147

    Abstract Continuous growth in industrialization and lack of awareness in safety parameters the cases of amputations are growing. The search of safer, simpler and automated prosthetic arms for managing upper limbs is expected. Continuous efforts have been made to design and develop prosthetic arms ranging from simple harness actuated to automated mechanisms with various control options. However due the cost constraints, the automated prosthetic arms are still out of the reach of needy people. Recent data have shown that there is a wide scope to develop a low cost and light weight upper limb prosthesis. This review summarizes the various designs… More >

  • Open Access

    ARTICLE

    Quick Construction of Femoral Model Using Surface Feature Parameterization

    Xiaozhong Chen∗,†, Kunjin He, Zhengming Chen∗,‡, Wei Xiang§

    Molecular & Cellular Biomechanics, Vol.12, No.2, pp. 123-146, 2015, DOI:10.3970/mcb.2015.012.123

    Abstract To facilitate the modifying of femoral surface model, by dividing the femoral mesh into surface feature units bearing medical significance based on surface feature technology, a new approach of constructing femoral models using surface feature technology is proposed. Firstly, considering of femoral anatomy, the femoral triangle mesh model generated from the averaged point-clouds is divided into several specific regions, which are called feature regions; Secondly, feature parameters are defined and the constraints among them are set up, and feature surfaces are created by skinning the contours; Finally, the adjacent feature surfaces are connected by transition surfaces, and the parametric CAD… More >

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