1,200 results match your criteria Biomechanics and modeling in mechanobiology[Journal]


Effects of macro-cracks on the load bearing capacity of articular cartilage.

Biomech Model Mechanobiol 2019 Apr 16. Epub 2019 Apr 16.

Faculty of Kinesiology, University of Calgary, 2500 University Dr. NW, Calgary, T2N 1N4, Canada.

Macro-cracks on the surface of articular cartilage are one of the hallmarks of early osteoarthritis and joint damage initiation. Macro-cracks negatively affect cartilage mechanobiology and load bearing capacity. The aim of this study was to quantify the changes in transient and steady-state force response of healthy cartilage in the presence of macro-cracks when compressed. Read More

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http://dx.doi.org/10.1007/s10237-019-01149-xDOI Listing

Tricuspid valve leaflet strains in the beating ovine heart.

Biomech Model Mechanobiol 2019 Apr 12. Epub 2019 Apr 12.

Department of Biomedical Engineering, University of Texas at Austin, 2501 Speedway, Room 7.620, Austin, TX, 78712, USA.

The tricuspid leaflets coapt during systole to facilitate proper valve function and, thus, ensure efficient transport of deoxygenated blood to the lungs. Between their open state and closed state, the leaflets undergo large deformations. Quantification of these deformations is important for our basic scientific understanding of tricuspid valve function and for diagnostic or prognostic purposes. Read More

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http://dx.doi.org/10.1007/s10237-019-01148-yDOI Listing

A growth-based model for the prediction of fiber angle distribution in the intervertebral disc annulus fibrosus.

Biomech Model Mechanobiol 2019 Apr 12. Epub 2019 Apr 12.

Department of Mechanical and Aeronautical Engineering, Clarkson University, 8 Clarkson Ave, Box 5725, Potsdam, NY, 13699, USA.

There is a growing interest in the development of patient-specific finite element models of the human lumbar spine for both the assessment of injury risk and the development of treatment strategies. A current challenge in implementing these models is that the outer annulus fibrosus of the disc is composed of concentric sheets of aligned collagen fibers, the helical angles of which vary spatially. In finite element models, fiber angle is typically assumed to be constant, based on average experimental measurements from a small number of locations. Read More

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http://dx.doi.org/10.1007/s10237-019-01150-4DOI Listing

Spatial scaling in multiscale models: methods for coupling agent-based and finite-element models of wound healing.

Biomech Model Mechanobiol 2019 Apr 9. Epub 2019 Apr 9.

Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA.

Multiscale models that couple agent-based modeling (ABM) and finite-element modeling (FEM) allow the dynamic simulation of tissue remodeling and wound healing, with mechanical environment influencing cellular behaviors even as tissue remodeling modifies mechanics. One of the challenges in coupling ABM to FEM is that these two domains typically employ grid or element sizes that differ by several orders of magnitude. Here, we develop and demonstrate an interpolation-based method for mapping between ABM and FEM domains of different resolutions that is suitable for linear and nonlinear FEM meshes and balances accuracy with computational demands. Read More

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http://dx.doi.org/10.1007/s10237-019-01145-1DOI Listing

Crack propagation in cortical bone is affected by the characteristics of the cement line: a parameter study using an XFEM interface damage model.

Biomech Model Mechanobiol 2019 Apr 8. Epub 2019 Apr 8.

Department of Biomedical Engineering, Lund University, Box 118, 221 00, Lund, Sweden.

Bulk properties of cortical bone have been well characterized experimentally, and potent toughening mechanisms, e.g., crack deflections, have been identified at the microscale. Read More

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http://dx.doi.org/10.1007/s10237-019-01142-4DOI Listing

A novel, FFT-based one-dimensional blood flow solution method for arterial network.

Biomech Model Mechanobiol 2019 Apr 6. Epub 2019 Apr 6.

Biomedical Engineering Group, Zienkiweicz Centre for Computational Engineering, College of Engineering, Swansea University, Bay Campus, Fabian Road, Swansea, SA2 8PP, UK.

In the present work, we propose an FFT-based method for solving blood flow equations in an arterial network with variable properties and geometrical changes. An essential advantage of this approach is in correctly accounting for the vessel skin friction through the use of Womersley solution. To incorporate nonlinear effects, a novel approximation method is proposed to enable calculation of nonlinear corrections. Read More

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http://dx.doi.org/10.1007/s10237-019-01146-0DOI Listing
April 2019
1 Read

Exploring conditions that make cortical bone geometry optimal for physiological loading.

Biomech Model Mechanobiol 2019 Apr 5. Epub 2019 Apr 5.

Department of Mechanical Engineering, Indian Institute of Technology Ropar, Satish Dhawan Block, Room No. 308, Rupnagar, Punjab, 140001, India.

While physiological loading on lower long bones changes during bone development, the bone cross section either remains circular or slowly changes from nearly circular to other shapes such as oval and roughly triangular. Bone is said to be an optimal structure, where strength is maximized using the optimal distribution of bone mass (also called Wolff's law). One of the most appropriate mathematical validations of this law would be a structural optimization-based formulation where total strain energy is minimized against a mass and a space constraint. Read More

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http://dx.doi.org/10.1007/s10237-019-01147-zDOI Listing
April 2019
1 Read

On the AIC-based model reduction for the general Holzapfel-Ogden myocardial constitutive law.

Biomech Model Mechanobiol 2019 Apr 3. Epub 2019 Apr 3.

School of Mathematics and Statistics, University of Glasgow, Glasgow, UK.

Constitutive laws that describe the mechanical responses of cardiac tissue under loading hold the key to accurately model the biomechanical behaviour of the heart. There have been ample choices of phenomenological constitutive laws derived from experiments, some of which are quite sophisticated and include effects of microscopic fibre structures of the myocardium. A typical example is the strain-invariant-based Holzapfel-Ogden 2009 model that is excellently fitted to simple shear tests. Read More

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http://dx.doi.org/10.1007/s10237-019-01140-6DOI Listing
April 2019
1 Read

In silico approach to quantify nucleus self-deformation on micropillared substrates.

Biomech Model Mechanobiol 2019 Apr 2. Epub 2019 Apr 2.

LBM/Institut de Biomécanique Humaine Georges Charpak, Arts et Metiers ParisTech, 151 Boulevard de l'Hôpital, Paris, France.

Considering the major role of confined cell migration in biological processes and diseases, such as embryogenesis or metastatic cancer, it has become increasingly important to design relevant experimental set-ups for in vitro studies. Microfluidic devices have recently presented great opportunities in their respect since they offer the possibility to study all the steps from a suspended to a spread, and eventually crawling cell or a cell with highly deformed nucleus. Here, we focus on the nucleus self-deformation over a micropillared substrate. Read More

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http://dx.doi.org/10.1007/s10237-019-01144-2DOI Listing
April 2019
1 Read

Multi-factor decision-making strategy for better coronary plaque burden increase prediction: a patient-specific 3D FSI study using IVUS follow-up data.

Biomech Model Mechanobiol 2019 Apr 1. Epub 2019 Apr 1.

The Cardiovascular Research Foundation, Columbia University, New York, NY, USA.

Plaque progression and vulnerability are influenced by many risk factors. Our goal is to find a simple method to combine multiple risk factors for better plaque development prediction. Intravascular ultrasound data at baseline and follow-up were acquired from nine patients, and fluid-structure interaction models were constructed to obtain plaque wall stress/strain (PWS/PWSn) and wall shear stress (WSS). Read More

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http://dx.doi.org/10.1007/s10237-019-01143-3DOI Listing
April 2019
1 Read

Experimental study of muscle permeability under various loading conditions.

Biomech Model Mechanobiol 2019 Mar 27. Epub 2019 Mar 27.

Department of Biomedical Engineering, Ben-Gurion University, 8410501, Beer-Sheva, Israel.

The permeability of a few muscle tissues under various loading conditions is characterized. To this end, we develop an experimental apparatus for permeability measurements which is based on the falling head method. We also design a dedicated sample holder which directs the flow through the tissue and simultaneously enables to pre-compress it. Read More

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http://dx.doi.org/10.1007/s10237-019-01138-0DOI Listing
March 2019
1 Read

A microscopically motivated model for the remodeling of cardiomyocytes.

Biomech Model Mechanobiol 2019 Mar 27. Epub 2019 Mar 27.

Department of Materials, University of California, Santa Barbara, CA, USA.

We present a thermodynamically based model that captures the remodeling effects in cardiac muscle cells. This work begins with the formulation of the kinematics of a cardiomyocyte resulting from a prescribed macroscopic deformation and the reorganization of the internal structure. Specifically, relations between the macroscopic deformation and the number of sarcomeres, the sarcomere stretch, and the number of myofibrils in the cell are determined. Read More

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http://dx.doi.org/10.1007/s10237-019-01141-5DOI Listing
March 2019
1 Read

Kinetics of the coagulation cascade including the contact activation system: sensitivity analysis and model reduction.

Biomech Model Mechanobiol 2019 Mar 21. Epub 2019 Mar 21.

IMAG, Univ Montpellier, CNRS, Montpellier, France.

Thrombus formation is one of the main issues in the development of blood-contacting medical devices. This article focuses on the modeling of one aspect of thrombosis, the coagulation cascade, which is initiated by the contact activation at the device surface and forms thrombin. Models exist representing the coagulation cascade by a series of reactions, usually solved in quiescent plasma. Read More

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http://dx.doi.org/10.1007/s10237-019-01134-4DOI Listing

A novel porous media-based approach to outflow boundary resistances of 1D arterial blood flow models.

Biomech Model Mechanobiol 2019 Mar 21. Epub 2019 Mar 21.

Zienkiewicz Centre for Computational Engineering, College of Engineering, Swansea University, Swansea, UK.

In this paper we introduce a novel method for prescribing terminal boundary conditions in one-dimensional arterial flow networks. This is carried out by coupling the terminal arterial vessel with a poro-elastic tube, representing the flow resistance offered by microcirculation. The performance of the proposed porous media-based model has been investigated through several different numerical examples. Read More

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http://dx.doi.org/10.1007/s10237-019-01122-8DOI Listing
March 2019
6 Reads

Lateral impacts correlate with falx cerebri displacement and corpus callosum trauma in sports-related concussions.

Biomech Model Mechanobiol 2019 Mar 12. Epub 2019 Mar 12.

Department of Mechanical Engineering, Stanford University, Stanford, CA, 94305, USA.

Corpus callosum trauma has long been implicated in mild traumatic brain injury (mTBI), yet the mechanism by which forces penetrate this structure is unknown. We investigated the hypothesis that coronal and horizontal rotations produce motion of the falx cerebri that damages the corpus callosum. We analyzed previously published head kinematics of 115 sports impacts (2 diagnosed mTBI) measured with instrumented mouthguards and used finite element (FE) simulations to correlate falx displacement with corpus callosum deformation. Read More

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http://dx.doi.org/10.1007/s10237-018-01106-0DOI Listing
March 2019
1 Read

Modeling and prediction of flow-induced hemolysis: a review.

Biomech Model Mechanobiol 2019 Mar 7. Epub 2019 Mar 7.

Biofluid Mechanics Laboratory, Department of Mechanical Engineering, University of Louisville, Louisville, USA.

Despite decades of research related to hemolysis, the accuracy of prediction algorithms for complex flows leaves much to be desired. Fundamental questions remain about how different types of fluid stresses translate to red cell membrane failure. While cellular- and molecular-level simulations hold promise, spatial resolution to such small scales is computationally intensive. Read More

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http://dx.doi.org/10.1007/s10237-019-01137-1DOI Listing

Modelling actin polymerization: the effect on confined cell migration.

Biomech Model Mechanobiol 2019 Mar 1. Epub 2019 Mar 1.

Universidad de Zaragoza, Campus Rio Ebro, 50018, Zaragoza, Spain.

The aim of this work is to model cell motility under conditions of mechanical confinement. This cell migration mode may occur in extravasation of tumour and neutrophil-like cells. Cell migration is the result of the complex action of different forces exerted by the interplay between myosin contractility forces and actin processes. Read More

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http://link.springer.com/10.1007/s10237-019-01136-2
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http://dx.doi.org/10.1007/s10237-019-01136-2DOI Listing
March 2019
3 Reads

Shear stress in the microvasculature: influence of red blood cell morphology and endothelial wall undulation.

Biomech Model Mechanobiol 2019 Mar 6. Epub 2019 Mar 6.

Hydrodynamics Laboratory (LadHyX), École Polytechnique, Palaiseau, France.

The effect of red blood cells and the undulation of the endothelium on the shear stress in the microvasculature is studied numerically using the lattice Boltzmann-immersed boundary method. The results demonstrate a significant effect of both the undulation of the endothelium and red blood cells on wall shear stress. Our results also reveal that morphological alterations of red blood cells, as occur in certain pathologies, can significantly affect the values of wall shear stress. Read More

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http://dx.doi.org/10.1007/s10237-019-01130-8DOI Listing
March 2019
4 Reads

A data-driven model to study utero-ovarian blood flow physiology during pregnancy.

Biomech Model Mechanobiol 2019 Mar 5. Epub 2019 Mar 5.

College of Engineering, Swansea University, Bay Campus, Fabian Way, Swansea, SA1 8EN, UK.

In this paper, we describe a mathematical model of the cardiovascular system in human pregnancy. An automated, closed-loop 1D-0D modelling framework was developed, and we demonstrate its efficacy in (1) reproducing measured multi-variate cardiovascular variables (pulse pressure, total peripheral resistance and cardiac output) and (2) providing automated estimates of variables that have not been measured (uterine arterial and venous blood flow, pulse wave velocity, pulsatility index). This is the first model capable of estimating volumetric blood flow to the uterus via the utero-ovarian communicating arteries. Read More

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http://link.springer.com/10.1007/s10237-019-01135-3
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http://dx.doi.org/10.1007/s10237-019-01135-3DOI Listing
March 2019
3 Reads

Patient-specific in silico endovascular repair of abdominal aortic aneurysms: application and validation.

Biomech Model Mechanobiol 2019 Mar 4. Epub 2019 Mar 4.

Mechanics and High Performance Computing Group, Technische Universität München, Parkring 35, 85748, Garching b. München, Germany.

Non-negligible postinterventional complication rates after endovascular aneurysm repair (EVAR) leave room for further improvements. Since the potential success of EVAR depends on various patient-specific factors, such as the complexity of the vessel geometry and the physiological state of the vessel, in silico models can be a valuable tool in the preinterventional planning phase. A suitable in silico EVAR methodology applied to patient-specific cases can be used to predict stent-graft (SG)-related complications, such as SG migration, endoleaks or tissue remodeling-induced aortic neck dilatation and to improve the selection and sizing process of SGs. Read More

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http://dx.doi.org/10.1007/s10237-019-01125-5DOI Listing
March 2019
1 Read

The morphology of the human mandible: A computational modelling study.

Biomech Model Mechanobiol 2019 Mar 2. Epub 2019 Mar 2.

Department of Biomedical Engineering, University of Melbourne, Parkville, VIC, 3010, Australia.

Cephalometric methods have been used to evaluate morphometric measurements of the mandible and quantify sex-related anatomical features; however, most studies to date employ a limited set of location-specific measurements without considering the entire three-dimensional anatomy of the mandible. The aims of this study were to develop statistical shape models (SSMs) of partially edentulous male and female mandibles to evaluate inter-subject morphological variability and secondly to assess the effectiveness of discrete clinical morphometric measurements in prediction of complete three-dimensional mandible geometry. Computed tomography images of forty partially edentulous female and twenty-five male subjects were obtained, and SSM developed using mesh fitting, rigid body registration and principal component analysis. Read More

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http://dx.doi.org/10.1007/s10237-019-01133-5DOI Listing

A CFD-based Kriging surrogate modeling approach for predicting device-specific hemolysis power law coefficients in blood-contacting medical devices.

Biomech Model Mechanobiol 2019 Feb 27. Epub 2019 Feb 27.

Division of Applied Mechanics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, United States Food and Drug Administration, Silver Spring, MD, USA.

Most stress-based hemolysis models used in computational fluid dynamics (CFD) are based on an empirical power law correlation between hemolysis generation and the flow-induced stress and exposure time. Empirical model coefficients are typically determined by fitting global hemolysis measurements in simplified blood shearing devices under uniform shear conditions and with well-defined exposure times. CFD simulations using these idealized global empirical coefficients are then performed to predict hemolysis in a medical device with complex hemodynamics. Read More

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http://dx.doi.org/10.1007/s10237-019-01126-4DOI Listing
February 2019
4 Reads

Fluid dynamics and forces in the HH25 avian embryonic outflow tract.

Biomech Model Mechanobiol 2019 Feb 27. Epub 2019 Feb 27.

Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore.

The embryonic outflow tract (OFT) eventually undergoes aorticopulmonary septation to form the aorta and pulmonary artery, and it is hypothesized that blood flow mechanical forces guide this process. We performed detailed studies of the geometry, wall motions, and fluid dynamics of the HH25 chick embryonic OFT just before septation, using noninvasive 4D high-frequency ultrasound and computational flow simulations. The OFT exhibited expansion and contraction waves propagating from proximal to distal end, with periods of luminal collapse at locations of the two endocardial cushions. Read More

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http://dx.doi.org/10.1007/s10237-019-01132-6DOI Listing
February 2019

On the compressibility and poroelasticity of human and murine skin.

Biomech Model Mechanobiol 2019 Feb 26. Epub 2019 Feb 26.

Department of Mechanical and Process Engineering, Institute for Mechanical Systems, ETH Zurich, 8092, Zurich, Switzerland.

A total of 37 human and 33 murine skin samples were subjected to uniaxial monotonic, cyclic, and relaxation experiments. Detailed analysis of the three-dimensional kinematic response showed that skin volume is significantly reduced as a consequence of a tensile elongation. This behavior is most pronounced in monotonic but persists in cyclic tests. Read More

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http://dx.doi.org/10.1007/s10237-019-01129-1DOI Listing
February 2019
1 Read

Enhanced cancer cell invasion caused by fibroblasts when fluid flow is present.

Biomech Model Mechanobiol 2019 Feb 22. Epub 2019 Feb 22.

University of Stavanger, 4068, Stavanger, Norway.

It has been demonstrated that interstitial fluid (IF) flow can play a crucial role in tumor cell progression. Swartz and collaborators (Cancer Cell 11: 526-538, Shields et al. 2007) demonstrated that cells that secrete the lymphoid homing chemokines CCL21/CCL19 and express their receptor CCR7 could use flow to bias the secreted chemokine, causing pericellular gradients that stimulate cells to migrate in the direction of the flow. Read More

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http://link.springer.com/10.1007/s10237-019-01128-2
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http://dx.doi.org/10.1007/s10237-019-01128-2DOI Listing
February 2019
9 Reads

A computational fluid dynamics approach to determine white matter permeability.

Biomech Model Mechanobiol 2019 Feb 20. Epub 2019 Feb 20.

Department of Mechanical Engineering, Imperial College London, London, SW7 2AZ, UK.

Glioblastomas represent a challenging problem with an extremely poor survival rate. Since these tumour cells have a highly invasive character, an effective surgical resection as well as chemotherapy and radiotherapy is very difficult. Convection-enhanced delivery (CED), a technique that consists in the injection of a therapeutic agent directly into the parenchyma, has shown encouraging results. Read More

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http://dx.doi.org/10.1007/s10237-019-01131-7DOI Listing
February 2019

Transient active force generation and stress fibre remodelling in cells under cyclic loading.

Biomech Model Mechanobiol 2019 Feb 19. Epub 2019 Feb 19.

Discipline of Biomedical Engineering, National University of Ireland Galway, Galway, Ireland.

The active cytoskeleton is known to play an important mechanistic role in cellular structure, spreading, and contractility. Contractility is actively generated by stress fibres (SF), which continuously remodel in response to physiological dynamic loading conditions. The influence of actin-myosin cross-bridge cycling on SF remodelling under dynamic loading conditions has not previously been uncovered. Read More

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http://dx.doi.org/10.1007/s10237-019-01121-9DOI Listing
February 2019

Surface deformation tracking and modelling of soft materials.

Biomech Model Mechanobiol 2019 Feb 18. Epub 2019 Feb 18.

Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.

Many computer vision algorithms have been presented to track surface deformations, but few have provided a direct comparison of measurements with other stereoscopic approaches and physics-based models. We have previously developed a phase-based cross-correlation algorithm to track dense distributions of displacements over three-dimensional surfaces. In the present work, we compare this algorithm with one that uses an independent tracking system, derived from an array of fluorescent microspheres. Read More

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http://dx.doi.org/10.1007/s10237-019-01127-3DOI Listing
February 2019

Homogenization of heterogeneous brain tissue under quasi-static loading: a visco-hyperelastic model of a 3D RVE.

Biomech Model Mechanobiol 2019 Feb 14. Epub 2019 Feb 14.

School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, 11155-4563, Iran.

Researches, in the recent years, reveal the utmost importance of brain tissue assessment regarding its mechanical properties, especially for automatic robotic tools, surgical robots and helmet producing. For this reason, experimental and computational investigation of the brain behavior under different conditions seems crucial. However, experiments do not normally show the distribution of stress and injury in microscopic scale, and due to various factors are costly. Read More

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http://dx.doi.org/10.1007/s10237-019-01124-6DOI Listing
February 2019

Direct and inverse identification of constitutive parameters from the structure of soft tissues. Part 2: dispersed arrangement of collagen fibers.

Biomech Model Mechanobiol 2019 Feb 9. Epub 2019 Feb 9.

Institut für Kontinuumsmechanik, Gottfried Wilhelm Leibniz Universität Hannover, Appelstr. 11, 30167, Hannover, Germany.

This paper investigates on the relationship between the arrangement of collagen fibers within soft tissues and parameters of constitutive models. Starting from numerical experiments based on biaxial loading conditions, the study addresses both the direct (from structure to mechanics) and the inverse (from mechanics to structure) problems, solved introducing optimization problems for model calibration and regression analysis. A campaign of parametric analyses is conducted in order to consider fibers distributions with different main orientation and angular dispersion. Read More

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http://dx.doi.org/10.1007/s10237-019-01119-3DOI Listing
February 2019

The combined impact of tissue heterogeneity and fixed charge for models of cartilage: the one-dimensional biphasic swelling model revisited.

Biomech Model Mechanobiol 2019 Feb 6. Epub 2019 Feb 6.

Mathematical Institute, University of Oxford, Oxford, UK.

Articular cartilage is a complex, anisotropic, stratified tissue with remarkable resilience and mechanical properties. It has been subject to extensive modelling as a multiphase medium, with many recent studies examining the impact of increasing detail in the representation of this tissue's fine scale structure. However, further investigation of simple models with minimal constitutive relations can nonetheless inform our understanding at the foundations of soft tissue simulation. Read More

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http://dx.doi.org/10.1007/s10237-019-01123-7DOI Listing
February 2019
1 Read

Tortuosity of the superficial femoral artery and its influence on blood flow patterns and risk of atherosclerosis.

Biomech Model Mechanobiol 2019 Jan 16. Epub 2019 Jan 16.

School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, No. 800 Dongchuan Road, Shanghai, 200240, China.

The superficial femoral artery (SFA) is a typical atherosclerosis-prone site. We aimed to explore whether the tortuosity of the SFA associates with the occurrence of atherosclerosis and investigate how vascular tortuosity influences the characteristics of blood flow. Ten patients diagnosed with atherosclerotic disease in their SFAs while free of systemic atherosclerosis risk factors were enrolled together with ten atherosclerosis-free patients. Read More

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http://dx.doi.org/10.1007/s10237-019-01118-4DOI Listing
January 2019

Evolution of hemodynamic forces in the pulmonary tree with progressively worsening pulmonary arterial hypertension in pediatric patients.

Biomech Model Mechanobiol 2019 Jan 12. Epub 2019 Jan 12.

Departments of Pediatrics and Bioengineering, Stanford University, Stanford, CA, USA.

Pulmonary arterial hypertension (PAH) is characterized by pulmonary vascular remodeling resulting in right ventricular (RV) dysfunction and ultimately RV failure. Mechanical stimuli acting on the vessel walls of the full pulmonary tree have not previously been comprehensively characterized. The goal of this study is to characterize wall shear stress (WSS) and strain in pediatric PAH patients at different stages of disease severity using computational patient-specific modeling. Read More

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http://dx.doi.org/10.1007/s10237-018-01114-0DOI Listing
January 2019
5 Reads

A computer-based simulation of childbirth using the partial Dirichlet-Neumann contact method with total Lagrangian explicit dynamics on the GPU.

Biomech Model Mechanobiol 2019 Jan 12. Epub 2019 Jan 12.

Department of Obstetrics and Gynaecology, Norfolk and Norwich University Hospital NHS Trust, Norwich, UK.

During physiological or 'natural' childbirth, the fetal head follows a distinct motion pattern-often referred to as the cardinal movements or 'mechanisms' of childbirth-due to the biomechanical interaction between the fetus and maternal pelvic anatomy. The research presented in this paper introduces a virtual reality-based simulation of physiological childbirth. The underpinning science is based on two numerical algorithms including the total Lagrangian explicit dynamics method to calculate soft tissue deformation and the partial Dirichlet-Neumann contact method to calculate the mechanical contact interaction between the fetal head and maternal pelvic anatomy. Read More

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http://dx.doi.org/10.1007/s10237-018-01109-xDOI Listing
January 2019

Simulation of the uterine contractions and foetus expulsion using a chemo-mechanical constitutive model.

Biomech Model Mechanobiol 2019 Jan 11. Epub 2019 Jan 11.

Faculty of Engineering, University of Porto, R. Dr. Roberto Frias, s/n, 4200, Oporto, Portugal.

During vaginal delivery women sustain stretching of their pelvic floor, risking tissue injury and adverse outcomes. Since studies in pregnant women are limited with ethical constraints, computational models have become an interesting alternative to elucidate the pregnancy mechanisms. This research investigates the uterine contractions during foetus expulsion without an imposed trajectory. Read More

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http://dx.doi.org/10.1007/s10237-019-01117-5DOI Listing
January 2019
1 Read

Maximum shear strain-based algorithm can predict proteoglycan loss in damaged articular cartilage.

Biomech Model Mechanobiol 2019 Jan 10. Epub 2019 Jan 10.

Department of Applied Physics, University of Eastern Finland, Yliopistonranta 1, POB 1627, 70211, Kuopio, Finland.

Post-traumatic osteoarthritis (PTOA) is a common disease, where the mechanical integrity of articular cartilage is compromised. PTOA can be a result of chondral defects formed due to injurious loading. One of the first changes around defects is proteoglycan depletion. Read More

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http://dx.doi.org/10.1007/s10237-018-01113-1DOI Listing
January 2019

Personalised deposition maps for micro- and nanoparticles targeting an atherosclerotic plaque: attributions to the receptor-mediated adsorption on the inflamed endothelial cells.

Biomech Model Mechanobiol 2019 Jan 7. Epub 2019 Jan 7.

School of Science and Engineering, Sharif University of Technology-International Campus, Kish, Iran.

Endothelial inflammation as a prominent precursor to atherosclerosis elicits a distinct pathological surface expression of particular vascular proteins. To exhibit a site-specific behaviour, micro- and nanoparticles, as carriers of therapeutics or imaging agents, can distinguish and use these proteins as targeted docking sites. Here, a computational patient-specific model capturing the exclusive luminal qualities has been developed to study the transport and adsorption of particles decorated with proper antibodies over an atherosclerotic plaque located in the LAD artery of the patient. Read More

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http://dx.doi.org/10.1007/s10237-018-01116-yDOI Listing
January 2019

Stochastic modeling of chemical-mechanical coupling in striated muscles.

Biomech Model Mechanobiol 2019 Jan 3. Epub 2019 Jan 3.

Inria - Université Paris-Saclay, 1 rue d'Estienne d'Orves, 91120, Palaiseau, France.

We propose a chemical-mechanical model of myosin heads in sarcomeres, within the classical description of rigid sliding filaments. In our case, myosin heads have two mechanical degrees-of-freedom (dofs)-one of which associated with the so-called power stroke-and two possible chemical states, i.e. Read More

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http://link.springer.com/10.1007/s10237-018-1102-z
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http://dx.doi.org/10.1007/s10237-018-1102-zDOI Listing
January 2019
11 Reads

Impacts of dynamic degradation on the morphological and mechanical characterisation of porous magnesium scaffold.

Biomech Model Mechanobiol 2019 Jan 3. Epub 2019 Jan 3.

Applied Mechanics and Design, School of Mechanical Engineering, Faculty of Engineering, Universiti Teknologi Malaysia (UTM), 81310, Johor Bahru, Malaysia.

This study employs a computational approach to analyse the impact of morphological changes on the structural properties of biodegradable porous Mg subjected to a dynamic immersion test for its application as a bone scaffold. Porous Mg was immersed in a dynamic immersion test for 24, 48, and 72 h. Twelve specimens were prepared and scanned using micro-CT and then reconstructed into a 3D model for finite element analysis. Read More

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http://dx.doi.org/10.1007/s10237-018-01115-zDOI Listing
January 2019

The effect of fibrillar degradation on the mechanics of articular cartilage: a computational model.

Biomech Model Mechanobiol 2019 Jan 2. Epub 2019 Jan 2.

Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, IL, USA.

The pathogenesis and pathophysiological underpinnings of cartilage degradation are not well understood. Either mechanically or enzymatically mediated degeneration at the fibril level can lead to acute focal injuries that will, overtime, cause significant cartilage degradation. Understanding the relationship between external loading and the basic molecular structure of cartilage requires establishing a connection between the fibril-level defects and its aggregate effect on cartilage. Read More

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http://dx.doi.org/10.1007/s10237-018-01112-2DOI Listing
January 2019

A computational reaction-diffusion model for biosynthesis and linking of cartilage extracellular matrix in cell-seeded scaffolds with varying porosity.

Biomech Model Mechanobiol 2019 Jan 2. Epub 2019 Jan 2.

Department of Mathematics, North Carolina State University, Box 8205, Raleigh, NC, 27695-8205, USA.

Cartilage tissue engineering is commonly initiated by seeding cells in porous materials such as hydrogels or scaffolds. Under optimal conditions, the resulting engineered construct has the potential to fill regions where native cartilage has degraded or eroded. Within a cell-seeded scaffold supplied by nutrients and growth factors, extracellular matrix accumulation should occur concurrently with scaffold degradation. Read More

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http://dx.doi.org/10.1007/s10237-018-01110-4DOI Listing
January 2019

A mechanism for injury through cerebral arteriole inflation.

Biomech Model Mechanobiol 2019 Jan 2. Epub 2019 Jan 2.

Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, 21218-2682, USA.

An increase in arterial pressure within the cerebral vasculature appears to coincide with ischemia and dysfunction of the neurovascular unit in some cases of traumatic brain injury. In this study, we examine a new mechanism of brain tissue damage that results from excessive cerebral arteriole pressurization. We begin by considering the morphological and material properties of normotensive and hypertensive arterioles and present a computational model that captures the interaction of neighboring pressurized arterioles and the surrounding brain tissue. Read More

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http://dx.doi.org/10.1007/s10237-018-01107-zDOI Listing
January 2019

On the representation of effective stress for computing hemolysis.

Authors:
P Wu Q Gao P-L Hsu

Biomech Model Mechanobiol 2019 Jan 2. Epub 2019 Jan 2.

Artificial Organ Technology Lab, Bio-manufacturing Research Centre, School of Mechanical and Electric Engineering, Soochow University, Suzhou, Jiangsu, China.

Hemolysis is a major concern in blood-circulating devices, which arises due to hydrodynamic loading on red blood cells from ambient flow environment. Hemolysis estimation models have often been used to aid hemocompatibility design. The preponderance of hemolysis models was formulated on the basis of laminar flows. Read More

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http://dx.doi.org/10.1007/s10237-018-01108-yDOI Listing
January 2019

Modelling of endothelial cell migration and angiogenesis in microfluidic cell culture systems.

Biomech Model Mechanobiol 2019 Jan 2. Epub 2019 Jan 2.

Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada.

Tumour-induced angiogenesis is a complex biological process that involves growth of new blood vessels within the tumour microenvironment and is an important target for cancer therapies. Significant efforts have been undertaken to develop theoretical models as well as in vitro experimental models to study angiogenesis in a highly controllable and accessible manner. Various mathematical models have been developed to study angiogenesis, but these have mostly been applied to in vivo assays. Read More

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http://dx.doi.org/10.1007/s10237-018-01111-3DOI Listing
January 2019
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Can the sheep model fully represent the human model for the functional evaluation of cervical interbody fusion cages?

Biomech Model Mechanobiol 2018 Dec 20. Epub 2018 Dec 20.

School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, 710054, Shaanxi, China.

Sheep model is the most favourable choice for animal study for functional evaluation of the cervical fusion prostheses before clinical application; however, significantly large differences between sheep and human existed in terms of morphological characteristics and daily-activity motions. Questions should be raised as whether the differences between the two species have influence on the reliability of sheep model. Finite element models (FEM) of the cervical spinal system were built to characterize the differences between the two species with respect to the range of motion (ROM) and biomechanical behaviour, and experimental cadaver tests on both species were employed for validation purposes. Read More

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http://dx.doi.org/10.1007/s10237-018-1104-xDOI Listing
December 2018
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Curvature- and fluid-stress-driven tissue growth in a tissue-engineering scaffold pore.

Biomech Model Mechanobiol 2018 Dec 12. Epub 2018 Dec 12.

Mathematical Institute, Radcliffe Observatory Quarter, University of Oxford, Oxford, OX2 6GG, UK.

Cell proliferation within a fluid-filled porous tissue-engineering scaffold depends on a sensitive choice of pore geometry and flow rates: regions of high curvature encourage cell proliferation, while a critical flow rate is required to promote growth for certain cell types. When the flow rate is too slow, the nutrient supply is limited; when it is too fast, cells may be damaged by the high fluid shear stress. As a result, determining appropriate tissue-engineering-construct geometries and operating regimes poses a significant challenge that cannot be addressed by experimentation alone. Read More

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http://dx.doi.org/10.1007/s10237-018-1103-yDOI Listing
December 2018

The importance of the pericardium for cardiac biomechanics: from physiology to computational modeling.

Biomech Model Mechanobiol 2019 Apr 10;18(2):503-529. Epub 2018 Dec 10.

Institute for Computational Mechanics, Technical University of Munich, Boltzmannstr. 15, 85748, Garching b. München, Germany.

The human heart is enclosed in the pericardial cavity. The pericardium consists of a layered thin sac and is separated from the myocardium by a thin film of fluid. It provides a fixture in space and frictionless sliding of the myocardium. Read More

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http://dx.doi.org/10.1007/s10237-018-1098-4DOI Listing
April 2019
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GAG content, fiber stiffness, and fiber angle affect swelling-based residual stress in the intact annulus fibrosus.

Biomech Model Mechanobiol 2018 Dec 10. Epub 2018 Dec 10.

Department of Mechanical Engineering, University of California, Berkeley, 5122 Etcheverry Hall, #1740, Berkeley, CA, 94720, USA.

Biological tissues with a high glycosaminoglycan (GAG) content have an excellent ability to swell by absorbing water molecules from the surrounding environment. Our recent work showed that anisotropy in tissue swelling depends on the fiber-network architecture, including fiber angle, fiber stiffness, and lamellae structure. However, that work did not evaluate the effect of in situ boundary conditions, such as the kidney-bean shape of the annulus fibrosus (AF), on swelling behavior. Read More

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http://dx.doi.org/10.1007/s10237-018-1105-9DOI Listing
December 2018
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CFPD simulation of magnetic drug delivery to a human lung using an SAW nebulizer.

Biomech Model Mechanobiol 2018 Nov 30. Epub 2018 Nov 30.

School of Mechanical Engineering, The University of Adelaide, Adelaide, SA, 5005, Australia.

Targeted drug delivery is an impressive topic that attracted the attention of many scientists in various scientific communities. Magnetic drug targeting is one of the targeted drug delivery techniques, which uses the magnetic field to externally control the magnetic drug particles. In this study, we aim to assess the magnetic drug delivery to the human respiratory system using a new aerosolization technique driven by surface acoustic waves (SAWs) into a realistic lung model geometrically reconstructed using computed tomography scan images. Read More

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http://dx.doi.org/10.1007/s10237-018-1101-0DOI Listing
November 2018

Soft palate muscle activation: a modeling approach for improved understanding of obstructive sleep apnea.

Biomech Model Mechanobiol 2018 Dec 3. Epub 2018 Dec 3.

Biomechanics Division, Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), 7491, Trondheim, Norway.

A Hill model-based phenomenological method for muscle activation was used to investigate defectiveness of the palatal muscle tone during sleep for obstructive sleep apnea (OSA) patients. Based on the stretch-stress characteristic of muscle activation when the eccentric contraction is considered, a specifically defined phenomenological strain-energy function was used, as well as the Holzapfel-type strain-energy function for the passive part. A continuum mechanical framework, including the stress tensor and elasticity tensor, was obtained, based on the defined strain-energy function. Read More

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http://dx.doi.org/10.1007/s10237-018-1100-1DOI Listing
December 2018
1 Read