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Molecular & Cellular Biomechanics: MCB

Longling Fan, Jing Yao, Chun Yang, Di Xu, Dalin Tang
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)...
2016: Molecular & Cellular Biomechanics: MCB
He Kunjin, Zou Zeyu, Zhang Rongli
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 to produce a volumetric feature (VF)...
December 2015: Molecular & Cellular Biomechanics: MCB
Jianhang Du, Liang Wang
Growing evidences suggest that long-term enhanced external counter-pulsation (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...
December 2015: Molecular & Cellular Biomechanics: MCB
Yan Cai, Jie Wu, Zhiyong Li
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...
December 2015: Molecular & Cellular Biomechanics: MCB
Ajith Rajapakshal, Michael Fink, Brian A Todd
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...
September 2015: Molecular & Cellular Biomechanics: MCB
Maryam Jazayeri, Mohammad Ali Shokrgozar, Nooshin Haghighipour, Reza Mahdian, Mehdi Farrokhi, Shahin Bonakdar, Fereshteh Mirahmadi, Tannaz Nourizadeh Abbariki
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...
September 2015: Molecular & Cellular Biomechanics: MCB
Tushar Kulkarni, Rashmi Uddanwadiker
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...
September 2015: Molecular & Cellular Biomechanics: MCB
Y Gür
The purpose of the study presented here was to investigate the manufacturability of human anatomical models from Computed Tomography (CT) scan data via a 3D desktop printer which uses fused deposition modelling (FDM) technology. First, Digital Imaging and Communications in Medicine (DICOM) CT scan data were converted to 3D Standard Triangle Language (STL) format by using In Vaselius digital imaging program. Once this STL file is obtained, a 3D physical version of the anatomical model can be fabricated by a desktop 3D FDM printer...
December 2014: Molecular & Cellular Biomechanics: MCB
Jiao Shi, Kun Cai, Qing H Qin
Simulation of the mass distribution in a human proximal femur is important to provide a reasonable therapy scheme for a patient with osteoporosis. An algorithm is developed for prediction of optimal mass distribution in a human proximal femur under a given loading environment. In this algorithm, the bone material is assumed to be bi-modulus, i.e., the tension modulus is not identical to the compression modulus in the same direction. With this bi-modulus bone material, a topology optimization method, i.e., modified SIMP approach, is employed to determine the optimal mass distribution in a proximal femur...
December 2014: Molecular & Cellular Biomechanics: MCB
M Moatamedi, M Souli, E Al-Bahkali
This paper describes the capabilities of fluid structure interaction based multi-physics numerical modelling in solving problems related to vascular biomechanics. In this research work, the onset of a pressure pulse was simulated at the entrance of a three dimensional straight segment of the blood vessel like circular tube and the resulting dynamic response in the form of a propagating pulse wave through the wall was analysed and compared. Good agreement was found between the numerical results and the theoretical description of an idealized artery...
December 2014: Molecular & Cellular Biomechanics: MCB
F S Tabatabaei, M Jazayeri, P Ghahari, N Haghighipour
During orthodontic treatments, applied mechanical forces create strain and result in tooth movement through the alveolar bone. This response to mechanical strain is a fundamental biological reaction. The present study evaluated the effect of equiaxial strain within the range of orthodontic forces on the osteogenic differentiation of human dental pulp stem cells (hDPSCs). Following isolation and culture of hDPSCs, 3rd passage cells were transferred on a silicone membrane covered with collagen. Cell adhesion to the membrane was evaluated under scanning electron microscope (SEM)...
September 2014: Molecular & Cellular Biomechanics: MCB
R Allena
Confined migration is a crucial phenomenon during embryogenesis, immune response and cancer. Here, a two-dimensional finite element model of a HeLa cell migrating across constricted-curved micro-channels is proposed. The cell is modelled as a continuum with embedded cytoplasm and nucleus, which are described by standard Maxwell viscoelastic models. The decomposition of the deformation gradient is employed to define the cyclic active strains of protrusion and contraction, which are synchronized with the adhesion forces between the cell and the substrate...
September 2014: Molecular & Cellular Biomechanics: MCB
S F Moreira, J Belinha, L M J S Dinis, R M Natal Jorge
In this work the maxillary central incisor is numerically analysed with an advance discretization technique--Natural Neighbour Radial Point Interpolation Method (NNRPIM). The NNRPIM permits to organically determine the nodal connectivity, which is essential to construct the interpolation functions. The NNRPIM procedure, based uniquely in the computational nodal mesh discretizing the problem domain, allows to obtain autonomously the required integration mesh, permitting to numerically integrate the differential equations ruling the studied physical phenomenon...
September 2014: Molecular & Cellular Biomechanics: MCB
Zheng-qi Liu, Ying Liu, Tian-tian Liu, Qing-shan Yang
In this paper, the hemodynamic characteristics of blood flow and stress distribution in a layered and stenotic aorta are investigated. By introducing symmetrical and unsymmetrical stenosis, the influence of stenosis morphology and stenotic ratio on the coupled dynamic responses of aorta is clarified. In the analysis, the in-vivo pulsatile waveforms and fully fluid-structure interaction (FSI) between the layered elastic aorta and the blood are considered. The results show that the fluid domain is abnormal in the stenotic aorta, and the whirlpool forms at the obstructed and downstream unobstructed regions...
June 2014: Molecular & Cellular Biomechanics: MCB
Chetan D Kuthe, R V Uddanwadiker, Alankar Ramteke
Biomechanical researches are essential to develop new techniques to improve the clinical relevance. Skeletal muscle generates the force which results in the motion of human body, so it is essential to study the mechanical and structural properties of skeletal muscle. Many researchers have carried out mechanical study of skeletal muscle with in-vivo testing. This work aims to examine anisotropic mechanical behavior of skeletal muscle with in vitro test (tensile test). It is important to understand the mechanical and structural behavior of skeletal muscle when it is subjected to external loading; the research aims to determine the structural properties of skeletal muscle by tensile...
June 2014: Molecular & Cellular Biomechanics: MCB
B Umadevi, P A Dinesh, R Indira, C V Vinay
The mass transfer in an eccentric annular region through diffusion by taking blood as a Newtonian fluid with the investigation of oxygen transfer and drug transport to the tissue cells in an eccentric catheterized artery is studied. The region bounded by eccentric circles in x-y plane is mapped conformally to concentric circles in ξ - η plane using a conformal mapping z = λ/1 - ζ. The resulting governing equations are analytically solved by using transformation for the concentration. Numerical computations are carried out to understand the simultaneous effects of absorption parameter and eccentricity on the flow...
June 2014: Molecular & Cellular Biomechanics: MCB
Li Na, Wei Wang, Bin Ye, Song Wu
ACL damage is one the most frequent causes of knee injuries and thus has long been the focus of research in biomechanics and sports medicine. Due to the anisometric geometry and functional complexity of the ACL in the knee joint, it is usually difficult to experimentally study the biomechanics of ACLs. Anatomically ACL geometry was obtained from both MR images and anatomical observations. The optimal material parameters of the ACL were obtained by using an optimization-based material identification method that minimized the differences between experimental results from ACL specimens and FE simulations...
June 2014: Molecular & Cellular Biomechanics: MCB
L L Xiao, S Chen, C S Lin, Y Liu
The motion and deformation of a single red blood cell flowing through a microvessel stenosis was investigated employing dissipative particle dynamics (DPD) method. The numerical model considers plasma, cytoplasm, the RBC membrane and the microvessel walls, in which a three dimensional coarse-grained spring RBC. The suspending plasma was modelled as an incompressible Newtonian fluid and the vessel walls were regarded as rigid body. The body force exerted on the free DPD particles was used to drive the flow. A modified bounce-back boundary condition was enforced on the membrane to guarantee the impenetrability...
March 2014: Molecular & Cellular Biomechanics: MCB
Hassan P Modarres, Mohammad R K Mofradt
Focal adhesions are the immediate sites of the cell's adhesive interaction with the extracellular matrix and as such play a key role in mechanosensing and mechanotransduction at the edge of the cell interface with its surrounding microenvironment. A multitude of proteins orchestrate this mechanochemical communication process between the cell and its outside world. Filamin is a member of focal adhesion protein machinery that also plays a key role in regulating and bundling the acting filament network. A brief review is presented here on filamin and its important protein partners with the aim to shed light on the role of filamin's protein-protein interaction network in cell mechanobiology...
March 2014: Molecular & Cellular Biomechanics: MCB
Norizadeh Abbariki Tannaz, Shokrgozar Mohammad Ali, Haghighipour Nooshin, Aghdami Nasser, Mahdian Reza, Amanzadeh Amir, Jazayeri Maryam
BACKGROUND: Environmental factors affect stem cell differentiation. In addition to chemical factors, mechanical signals have been suggested to enhance myogenic differentiation of stem cells. Therefore, this study was undertaken to illustrate and compare the effect of chemical and mechanical stimuli on Myogenin (MyoG) and Myosin heavy chani 2 (Myh2) expression of mouse bone marrow-derived mesenchymal stem cells (BMSCs) and embryonic stem cells (ESCs). METHODS: After isolation and expansion of BMSCs and generation of embryoid bodies and spontaneous differentiation of ESCs, cells were examined in 4 groups: (1) control group: untreated cells; (2) chemical group: cells incubated in myogenic medium (5-azacythidine and horse serum for BMSCs, dimethyl sulfoxide (DMSO) and horse serum for ESCs) for 5 days; (3) mechanical group: cells exposed to uniaxial cyclic strain (8%, 1 Hz, 24 h) and (4) chemical + mechanical group: cells incubated in myogenic medium for 4 days and then exposed to uniaxial cyclic strain...
March 2014: Molecular & Cellular Biomechanics: MCB
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