An orthotropic electro-viscoelastic model for the heart with stress-assisted diffusion.
Abstract We propose and analyse the properties of a new class of models for the electromechanics of cardiac tissue. The set of governing equations consists of nonlinear elasticity using a viscoelastic and orthotropic exponential constitutive law, for both active stress and active strain formulations of active mechanics, coupled with a four-variable phenomenological model for human cardiac cell electrophysiology, which produces an accurate description of the action potential. The conductivities in the model of electric propagation are modified according to stress, inducing an additional degree of nonlinearity and a...
Source: Biomechanics and Modeling in Mechanobiology - October 19, 2019 Category: Biomedical Science Authors: Propp A, Gizzi A, Levrero-Florencio F, Ruiz-Baier R Tags: Biomech Model Mechanobiol Source Type: research

A particle-based model for endothelial cell migration under flow conditions.
Abstract Endothelial cells (ECs) play a major role in the healing process following angioplasty to inhibit excessive neointima. This makes the process of EC healing after injury, in particular EC migration in a stented vessel, important for recovery of normal vessel function. In that context, we present a novel particle-based model of EC migration and validate it against in vitro experimental data. We have developed a particle-based model of EC migration under flow conditions in an in vitro vessel with obstacles. Cell movement in the model is a combination of random walks and directed movement along the local flow...
Source: Biomechanics and Modeling in Mechanobiology - October 17, 2019 Category: Biomedical Science Authors: Zun PS, Narracott AJ, Evans PC, van Rooij BJM, Hoekstra AG Tags: Biomech Model Mechanobiol Source Type: research

An energy-dissipation-based power-law formulation for estimating hemolysis.
This study proposed a new power-law formulation for the numerical hemolysis prediction. The new formulation related hemolysis to the energy dissipation rate, which could be readily obtained from CFD simulations. The model constants were regressed from existing hemolysis data. The new formulation was tested for three benchmark cases and compared to conventional power-law models. The results showed that the new formulation improved prediction of hemolysis for a broad range of flow regimes. The deviations of the predicted hemolysis from experimental results were within one order, and better correlated with experimental result...
Source: Biomechanics and Modeling in Mechanobiology - October 14, 2019 Category: Biomedical Science Authors: Wu P, Groß-Hardt S, Boehning F, Hsu PL Tags: Biomech Model Mechanobiol Source Type: research

Rate-dependent constitutive modeling of brain tissue.
Abstract In this paper, the dynamic behavior of bovine brain tissue, measured from a set of in vitro experiments, is investigated and represented through a nonlinear viscoelastic constitutive model. The brain samples were tested by employing unconfined compression tests at three different deformation rates of 10, 100, and 1000 mm/s. The tissue exhibited a significant rate-dependent behavior with different compression speeds. Based on the parallel rheological framework approach, a nonlinear viscoelastic model that captures the key aspects of the rate dependency in large-strain behavior was introduced. The...
Source: Biomechanics and Modeling in Mechanobiology - October 14, 2019 Category: Biomedical Science Authors: Hosseini-Farid M, Ramzanpour M, McLean J, Ziejewski M, Karami G Tags: Biomech Model Mechanobiol Source Type: research

The impact of geometrical parameters on acoustically driven drug delivery to maxillary sinuses.
Abstract Acoustically driven nebulized drug delivery (acoustic aerosol delivery) is the most efficient noninvasive technique for drug delivery to maxillary sinuses (MS). This method is based on the oscillation of the air plug inside the ostium to transport drug particles from the nasal cavity (NC) to the MS. The larger the wavelength of the air plug oscillation in the ostium, the greater the penetration of drug particles to the MS. However, using this technique, the maximum drug delivery efficiency achieved to date is 5%, which means 95% of the aerosolized drugs do not enter the MS and are wasted. Since the larges...
Source: Biomechanics and Modeling in Mechanobiology - October 1, 2019 Category: Biomedical Science Authors: Pourmehran O, Arjomandi M, Cazzolato B, Ghanadi F, Tian Z Tags: Biomech Model Mechanobiol Source Type: research

Multiscale modeling of solid stress and tumor cell invasion in response to dynamic mechanical microenvironment.
Abstract Mathematical models can provide a quantitatively sophisticated description of tumor cell (TC) behaviors under mechanical microenvironment and help us better understand the role of specific biophysical factors based on their influences on the TC behaviors. To this end, we propose an off-lattice cell-based multiscale mathematical model to describe the dynamic growth-induced solid stress during tumor progression and investigate the influence of the mechanical microenvironment on TC invasion. At the cellular level, cell-cell and cell-matrix interactive forces depend on the mechanical properties of the cells a...
Source: Biomechanics and Modeling in Mechanobiology - September 30, 2019 Category: Biomedical Science Authors: Chen H, Cai Y, Chen Q, Li Z Tags: Biomech Model Mechanobiol Source Type: research

A population-specific material model for sagittal craniosynostosis to predict surgical shape outcomes.
Abstract Sagittal craniosynostosis consists of premature fusion (ossification) of the sagittal suture during infancy, resulting in head deformity and brain growth restriction. Spring-assisted cranioplasty (SAC) entails skull incisions to free the fused suture and insertion of two springs (metallic distractors) to promote cranial reshaping. Although safe and effective, SAC outcomes remain uncertain. We aimed hereby to obtain and validate a skull material model for SAC outcome prediction. Computed tomography data relative to 18 patients were processed to simulate surgical cuts and spring location. A rescaling model ...
Source: Biomechanics and Modeling in Mechanobiology - September 30, 2019 Category: Biomedical Science Authors: Borghi A, Rodriguez Florez N, Ruggiero F, James G, O'Hara J, Ong J, Jeelani O, Dunaway D, Schievano S Tags: Biomech Model Mechanobiol Source Type: research

Helical structure of actin stress fibers and its possible contribution to inducing their direction-selective disassembly upon cell shortening.
Abstract Mechanisms of the assembly of actin stress fibers (SFs) have been extensively studied, while those of the disassembly-particularly cell shortening-induced ones-remain unclear. Here, we show that SFs have helical structures composed of multi-subbundles, and they tend to be delaminated upon cell shortening. Specifically, we observed with atomic force microscopy delamination of helical SFs into their subbundles. We physically caught individual SFs using a pair of glass needles to observe rotational deformations during stretching as well as ATP-driven active contraction, suggesting that they deform in a manne...
Source: Biomechanics and Modeling in Mechanobiology - September 23, 2019 Category: Biomedical Science Authors: Okamoto T, Matsui TS, Ohishi T, Deguchi S Tags: Biomech Model Mechanobiol Source Type: research

Effects on loads in temporomandibular joints for patients with mandibular asymmetry before and after orthognathic surgeries under the unilateral molar clenching.
Abstract Orthognathic surgery is a useful treatment for the correction of mandibular deformity. Different from other occlusions, unilateral occlusion is frequently used in mastication and influences functions of temporomandibular joints (TMJs). However, stress distributions in TMJ before and after orthognathic surgeries are not under consideration in treatments, crucial to pre- and postoperative temporomandibular disorders (TMDs). The study aims to analyze stress distributions in TMJs for patients with mandibular asymmetry before and after orthognathic surgeries under the unilateral molar clenching. Ten asymptomat...
Source: Biomechanics and Modeling in Mechanobiology - September 17, 2019 Category: Biomedical Science Authors: Shu J, Zhang Y, Chong DYR, Liu Z Tags: Biomech Model Mechanobiol Source Type: research

Modelling the electrical activity of skeletal muscle tissue using a multi-domain approach.
e O Abstract Electromyography (EMG) can be used to study the behaviour of the motor neurons and thus provides insights into the physiology of the central nervous system. However, due to the high complexity of neuromuscular control, EMG signals are challenging to interpret. While the exact knowledge of the excitation patterns of a specific muscle within an in vivo experimental setting remains elusive, simulations allow to systematically investigate EMG signals in a controlled environment. Within this context, simulations can provide virtual EMG data, which, for example, can be used to validate and optimise signal a...
Source: Biomechanics and Modeling in Mechanobiology - September 16, 2019 Category: Biomedical Science Authors: Klotz T, Gizzi L, Yavuz UŞ, Röhrle O Tags: Biomech Model Mechanobiol Source Type: research

Cell-substrate traction force regulates the fusion of osteoclast precursors through cell-cell interaction.
Abstract The adhesion morphology of a cell monolayer results in a mechanical force inside cells, between cells, or between cells and substrates. The mechanical force regulates the differentiation of stem cells, but its influence on cell fusion is seldom studied. The present study is focused on osteoclast precursors, RAW264.7 monocytes, which can fuse into multinucleated cells (MNCs) responsible for bone resorption. Cells were cultured on circular and ring-like patterned substrates. Then, cell fusion, cell-substrate traction force, and force-sensitive molecules in different regions were measured and analyzed. Resul...
Source: Biomechanics and Modeling in Mechanobiology - September 16, 2019 Category: Biomedical Science Authors: Sun Q, Liu C, Bai X, Huo B Tags: Biomech Model Mechanobiol Source Type: research

Modeling of the human mandibular periosteum material properties and comparison with the calvarial periosteum.
Abstract Knowledge of mandibular periosteum mechanical properties is fundamental for understanding its role in craniofacial growth, in trauma and bone regeneration. There is a lack in the literature regarding mechanical behavior of the human periosteum, including both experimental and modeling aspects. The proposed study involves tensile tests of periosteum samples from different locations including two locations of human mandibular periosteum: lingual and vestibular, compared with samples from various locations of the calvarial periosteum. We propose to analyze the tensile response of the mandibular periosteum us...
Source: Biomechanics and Modeling in Mechanobiology - September 11, 2019 Category: Biomedical Science Authors: Kadlub N, Debelmas A, Dallard J, Picard A, Boisson J Tags: Biomech Model Mechanobiol Source Type: research

Effect of fabric on the accuracy of computed tomography-based finite element analyses of the vertebra.
Abstract Quantitative computed tomography (QCT)-based finite element (FE) models of the vertebra are widely used in studying spine biomechanics and mechanobiology, but their accuracy has not been fully established. Although the models typically assign material properties based only on local bone mineral density (BMD), the mechanical behavior of trabecular bone also depends on fabric. The goal of this study was to determine the effect of incorporating measurements of fabric on the accuracy of FE predictions of vertebral deformation. Accuracy was assessed by using displacement fields measured via digital volume corr...
Source: Biomechanics and Modeling in Mechanobiology - September 10, 2019 Category: Biomedical Science Authors: Wu Y, Morgan EF Tags: Biomech Model Mechanobiol Source Type: research

Cyclic stretch-induced mechanical stress to the cell nucleus inhibits ultraviolet radiation-induced DNA damage.
Abstract Ultraviolet (UV) radiation exerts adverse effects on genome stability, alters the normal state of life, and causes several diseases by inducing DNA damage. Although mechanical stimulation such as stretching has significant effects on the prevention and treatment of diseases, its influence on nuclear morphology and/or intranuclear functions involving resistance to DNA damage remains unknown. Here, we investigated the effects of mechanical stimulation by cyclic stretching on nuclear morphology and resistance of DNA to UV damage in NIH3T3 fibroblasts. Adherent cells on silicone elastic membranes were subject...
Source: Biomechanics and Modeling in Mechanobiology - September 10, 2019 Category: Biomedical Science Authors: Nagayama K, Fukuei T Tags: Biomech Model Mechanobiol Source Type: research

Effect of structural distortions on articular cartilage permeability under large deformations.
Abstract The permeability of articular cartilage has a key role in load support and lubrication in diarthrodial joints. The microstructural rearrangement and consequent alteration in permeability caused by the large deformations undergone by cartilage have been previously modelled with a multi-scale approach. At the microscopic scale, the tissue is regarded as a homogeneous fluid-filled proteoglycan matrix reinforced by collagen fibres. A material point is described by a representative element of volume (REV), comprising a collagen fibre surrounded by a jacket of fluid-saturated proteoglycan matrix. At the macrosc...
Source: Biomechanics and Modeling in Mechanobiology - September 10, 2019 Category: Biomedical Science Authors: Maleki M, Hashlamoun K, Herzog W, Federico S Tags: Biomech Model Mechanobiol Source Type: research

Computational modeling of therapy on pancreatic cancer in its early stages.
Abstract More than eighty percent of pancreatic cancer involves ductal adenocarcinoma with an abundant desmoplastic extracellular matrix surrounding the solid tumor entity. This aberrant tumor microenvironment facilitates a strong resistance of pancreatic cancer to medication. Although various therapeutic strategies have been reported to be effective in mice with pancreatic cancer, they still need to be tested quantitatively in wider animal-based experiments before being applied as therapies. To aid the design of experiments, we develop a cell-based mathematical model to describe cancer progression under therapy w...
Source: Biomechanics and Modeling in Mechanobiology - September 9, 2019 Category: Biomedical Science Authors: Chen J, Weihs D, Vermolen FJ Tags: Biomech Model Mechanobiol Source Type: research

Primary cilia have a length-dependent persistence length.
Abstract The fluctuating position of an optically trapped cilium tip under untreated and Taxol-treated conditions was used to characterize mechanical properties of the cilium axoneme and its basal body by combining experimental, analytical, and computational tools. We provide, for the first time, evidence that the persistence length of a ciliary axoneme is length-dependent; longer cilia are stiffer than shorter cilia. We demonstrate that this apparent length dependence can be understood by a combination of modeling axonemal microtubules as anisotropic elastic shells and including actomyosin-driven stochastic basal...
Source: Biomechanics and Modeling in Mechanobiology - September 9, 2019 Category: Biomedical Science Authors: Flaherty J, Feng Z, Peng Z, Young YN, Resnick A Tags: Biomech Model Mechanobiol Source Type: research

Comparative study of variations in mechanical stress and strain of human blood vessels: mechanical reference for vascular cell mechano-biology.
In this study, six representative human blood vessels with known experimental measurements were selected, and their stress and strain variations in vessel walls under different blood pressures were analyzed based on nonlinear elastic theory. The results suggest that conventional mechano-biological experiments seeking the different biological expressions of cells at high/low mechanical loadings are ambiguous as references for studying vascular diseases, because distinct "site-specific" characteristics appear in different vessels. The present results demonstrate that the inner surface of the vessel wall does not al...
Source: Biomechanics and Modeling in Mechanobiology - September 7, 2019 Category: Biomedical Science Authors: Yang S, Gong X, Qi Y, Jiang Z Tags: Biomech Model Mechanobiol Source Type: research

An energy landscape approach to understanding variety and robustness in tissue morphogenesis.
Abstract During morphogenesis in development, multicellular tissues deform by mechanical forces induced by spatiotemporally regulated cellular activities, such as cell proliferation and constriction. Various morphologies are formed because of various spatiotemporal combinations and sequences of multicellular activities. Despite its potential to variations, morphogenesis is a surprisingly robust process, in which qualitatively similar morphologies are reproducibly formed even under spatiotemporal fluctuation of multicellular activities. To understand these essential characteristics of tissue morphogenesis, which in...
Source: Biomechanics and Modeling in Mechanobiology - September 7, 2019 Category: Biomedical Science Authors: Takeda H, Kameo Y, Inoue Y, Adachi T Tags: Biomech Model Mechanobiol Source Type: research

Effects of longitudinal pre-stretch on the mechanics of human aorta before and after thoracic endovascular aortic repair (TEVAR) in trauma patients.
Abstract Thoracic endovascular aortic repair (TEVAR) has evolved as a first-line therapy for trauma patients. Most trauma patients are young, and their aortas are compliant and longitudinally pre-stretched. We have developed a method to include longitudinal pre-stretch in computational models of human thoracic aortas of different ages before and after TEVAR. Finite element models were built using computerized tomography angiography data obtained from human subjects in 6 age groups 10-69 years old. Aortic properties were determined with planar biaxial testing, and pre-stretch was simulated using a series of sp...
Source: Biomechanics and Modeling in Mechanobiology - September 5, 2019 Category: Biomedical Science Authors: Desyatova A, MacTaggart J, Kamenskiy A Tags: Biomech Model Mechanobiol Source Type: research

Improvement in determining the risk of damage to the human lumbar functional spinal unit considering age, height, weight and sex using a combination of FEM and RSM.
ía R Abstract Human functional spinal unit (FSU) is comprised of two adjacent vertebrae, the intervertebral disc (IVD), the cartilage endplates and the connecting ligamentous tissues. As humans age, trabecular, cortical bone and IVD change in mechanical properties. These changes influence the movement of the FSU (displacements, rotations and disc bulges). This paper proposes a method to determine the influence of sex, age, weight and height on the movements of the FSU using a combination of the FEM and RSM. The work concentrates on the medium-sized human FSU (L3-L4 lumbar level with standard dimensions of I...
Source: Biomechanics and Modeling in Mechanobiology - August 31, 2019 Category: Biomedical Science Authors: Somovilla-Gómez F, Lostado-Lorza R, Corral-Bobadilla M, Escribano-García R Tags: Biomech Model Mechanobiol Source Type: research

Dissipative particle dynamics for modeling micro-objects in microfluidics: application to dielectrophoresis.
Abstract The dissipative particle dynamics (DPD) technique is employed to model the trajectories of micro-objects in a practical microfluidic device. The simulation approach is first developed using an in-house Fortran code to model Stokes flow at Reynolds number of 0.01. The extremely low Reynolds number is achieved by adjusting the DPD parameters, such as force coefficients, thermal energies of the particles, and time steps. After matching the numerical flow profile with the analytical results, the technique is developed further to simulate the deflection of micro-objects under the effect of a deflecting externa...
Source: Biomechanics and Modeling in Mechanobiology - August 31, 2019 Category: Biomedical Science Authors: Waheed W, Alazzam A, Al-Khateeb AN, Abu-Nada E Tags: Biomech Model Mechanobiol Source Type: research

Numerical models of valve-in-valve implantation: effect of intentional leaflet laceration on the anchorage.
This study aims to compare the anchorage post-ViV implantations, with and without lacerations, using numerical modelling. Deployments of TAVI stents (Medtronic Evolut PRO; Edwards SAPIEN 3) inside an externally mounted surgical bioprosthetic valve (Sorin Mitroflow) were modelled by finite element analysis. The results show that each laceration reduces the contact area of the TAVI stent with its landing zone and that the anchorage contact force weakens. The BASILICA technique has lesser effect on the anchorage contact area and forces in the SAPIEN than in the Evolut cases, because the balloon inflation is less sensitive to ...
Source: Biomechanics and Modeling in Mechanobiology - August 30, 2019 Category: Biomedical Science Authors: Yaakobovich H, Plitman Mayo R, Zaretsky U, Finkelstein A, Marom G Tags: Biomech Model Mechanobiol Source Type: research

4D modelling of fluid mechanics in the zebrafish embryonic heart.
Abstract Abnormal blood flow mechanics can result in pathological heart malformation, underlining the importance of understanding embryonic cardiac fluid mechanics. In the current study, we performed image-based computational fluid dynamics simulation of the zebrafish embryonic heart ventricles and characterized flow mechanics, organ dynamics, and energy dynamics in detail. 4D scans of 5 days post-fertilization embryonic hearts with GFP-labelled myocardium were acquired using line-scan focal modulation microscopy. This revealed that the zebrafish hearts exhibited a wave-like contractile/relaxation motion from...
Source: Biomechanics and Modeling in Mechanobiology - August 24, 2019 Category: Biomedical Science Authors: Foo YY, Pant S, Tay HS, Imangali N, Chen N, Winkler C, Yap CH Tags: Biomech Model Mechanobiol Source Type: research

Pneumatic unidirectional cell stretching device for mechanobiological studies of cardiomyocytes.
ml; K, Kallio P Abstract In this paper, we present a transparent mechanical stimulation device capable of uniaxial stimulation, which is compatible with standard bioanalytical methods used in cellular mechanobiology. We validate the functionality of the uniaxial stimulation system using human-induced pluripotent stem cells-derived cardiomyocytes (hiPSC-CMs). The pneumatically controlled device is fabricated from polydimethylsiloxane (PDMS) and provides uniaxial strain and superior optical performance compatible with standard inverted microscopy techniques used for bioanalytics (e.g., fluorescence microscopy and ca...
Source: Biomechanics and Modeling in Mechanobiology - August 23, 2019 Category: Biomedical Science Authors: Kreutzer J, Viehrig M, Pölönen RP, Zhao F, Ojala M, Aalto-Setälä K, Kallio P Tags: Biomech Model Mechanobiol Source Type: research

Inverse finite element characterization of the human thigh soft tissue in the seated position.
In this study, we compared how the choice of material model and modeling area dimension affect prediction accuracy of a model of the thigh. We showed that the first-order Ogden and Fung orthotropic material models could approximate the mechanical behavior of soft tissue significantly better than neo-Hookean and Mooney-Rivlin. We also showed that, significant error results from using a semi-3D model versus a 3D model. We then developed full 3D models for 20 participants employing Ogden and Fung material models and compared the estimated material parameters between different sexes and locations along the thigh. We showed tha...
Source: Biomechanics and Modeling in Mechanobiology - August 16, 2019 Category: Biomedical Science Authors: Chen S, Scott J, Bush TR, Roccabianca S Tags: Biomech Model Mechanobiol Source Type: research

Correction to: A computational fluid dynamics approach to determine white matter permeability.
Abstract The article "A computational fluid dynamics approach to determine white matter permeability" written by Marco Vidotto, Daniela Botnariuc, Elena De Momi and Daniele Dini was originally published electronically on the publisher's Internet portal (currently SpringerLink) on 20 February 2019 without open access. PMID: 31399856 [PubMed - as supplied by publisher] (Source: Biomechanics and Modeling in Mechanobiology)
Source: Biomechanics and Modeling in Mechanobiology - August 9, 2019 Category: Biomedical Science Authors: Vidotto M, Botnariuc D, De Momi E, Dini D Tags: Biomech Model Mechanobiol Source Type: research

Effects of buccal thickness augmentation on bone remodeling after maxillary anterior implantation.
In conclusion, this study introduced a self-validating bone remodeling algorithm in silico, and it divulged that the initial BBT affects the bone remodeling outcome significantly, and a sufficient initial BBT is considered essential to assure long-term stability and success of implant treatment. PMID: 31396806 [PubMed - as supplied by publisher] (Source: Biomechanics and Modeling in Mechanobiology)
Source: Biomechanics and Modeling in Mechanobiology - August 8, 2019 Category: Biomedical Science Authors: Zheng K, Yoda N, Chen J, Liao Z, Zhong J, Koyama S, Peck C, Swain M, Sasaki K, Li Q Tags: Biomech Model Mechanobiol Source Type: research

A microstructurally inspired constitutive model for skin mechanics.
This study investigates the link between the mechanical properties of skin and its microstructural characteristics. Rat back skin samples from different locations, orientations, and sexes were collected and subjected to quasi-static uniaxial tensile tests. Stress-stretch behavior at low stress ranges and rupture data at high stress ranges were collected. The influence of location, orientation, and sex on skin mechanical properties was examined by comparing the mechanical parameters (i.e., initial slope, maximum slope, ultimate tensile strength, rupture stretch, and toughness) evaluated from the tensile testing data. Locati...
Source: Biomechanics and Modeling in Mechanobiology - August 8, 2019 Category: Biomedical Science Authors: Chen S, Ní Annaidh A, Roccabianca S Tags: Biomech Model Mechanobiol Source Type: research

Evaluation of stimulus-effect relations in left ventricular growth using a simple multiscale model.
In this study, we use a zero-dimensional, multiscale model of the left ventricle to evaluate cardiac growth in response to three valve diseases, aortic and mitral regurgitation along with aortic stenosis. We investigate how different combinations of stress- and strain-based stimuli affect growth in terms of cavity volume and wall volume and hemodynamic performance. All of our simulations are able to reach a converged state without any growth constraint, with the most promising results obtained while considering at least one stress-based stimulus. With this study, we demonstrate how a simple model of left ventricular mechan...
Source: Biomechanics and Modeling in Mechanobiology - August 6, 2019 Category: Biomedical Science Authors: Rondanina E, Bovendeerd PHM Tags: Biomech Model Mechanobiol Source Type: research

Deformation of human red blood cells in extensional flow through a hyperbolic contraction.
In this study, experiments were conducted to compare human red cell deformation under laminar extensional stress versus laminar shear stress. It was found that the deformation caused by shear stress is matched by that produced by an extensional stress that is approximately 34 times smaller. Assuming that blood damage scales directly with cell deformation, this result indicates that mechanistic blood damage prediction models should weigh extensional stress more than shear stress. PMID: 31388870 [PubMed - as supplied by publisher] (Source: Biomechanics and Modeling in Mechanobiology)
Source: Biomechanics and Modeling in Mechanobiology - August 6, 2019 Category: Biomedical Science Authors: Faghih MM, Sharp MK Tags: Biomech Model Mechanobiol Source Type: research

How flexibility and eardrum cone shape affect sound conduction in single-ossicle ears: a dynamic model study of the chicken middle ear.
Abstract It is believed that non-mammals have poor hearing at high frequencies because the sound-conduction performance of their single-ossicle middle ears declines above a certain frequency. To better understand this behavior, a dynamic three-dimensional finite-element model of the chicken middle ear was constructed. The effect of changing the flexibility of the cartilaginous extracolumella on middle-ear sound conduction was simulated from 0.125 to 8 kHz, and the influence of the outward-bulging cone shape of the eardrum was studied by altering the depth and orientation of the eardrum cone in the model. It w...
Source: Biomechanics and Modeling in Mechanobiology - August 1, 2019 Category: Biomedical Science Authors: Muyshondt PGG, Dirckx JJJ Tags: Biomech Model Mechanobiol Source Type: research

Transition to turbulence in an oscillatory flow through stenosis.
Abstract Onset of flow transition in a sinusoidally oscillating flow through a rigid, constant area circular pipe with a smooth sinusoidal obstruction in the center of the pipe is studied by performing direct numerical simulations, with resolutions close to the Kolmogorov microscales. The studied pipe is stenosed in the center with a 75% reduction in area in two distinct configurations-one that is symmetric to the axis of the parent pipe and the other that is offset by 0.05 diameters to introduce an eccentricity, which disturbs the flow thereby triggering the onset of flow transition. The critical Reynolds number ...
Source: Biomechanics and Modeling in Mechanobiology - July 30, 2019 Category: Biomedical Science Authors: Jain K Tags: Biomech Model Mechanobiol Source Type: research

Finite element evaluation of artery damage in deployment of polymeric stent with pre- and post-dilation.
Abstract Using finite element method, this paper evaluates damage in an arterial wall and plaque caused by percutaneous coronary intervention. Hyperelastic damage models, calibrated with experimental results, are used to describe stress-stretch responses of arterial layers and plaque; these models are capable to simulate softening behaviour of the tissue due to damage. Abaqus CAE is employed to create the finite element models for the artery wall (with media and adventitia layers), a symmetric uniform plaque, a bioresorbable polymeric stent and a tri-folded expansion balloon. The effect of percutaneous coronary in...
Source: Biomechanics and Modeling in Mechanobiology - July 17, 2019 Category: Biomedical Science Authors: He R, Zhao LG, Silberschmidt VV, Liu Y, Vogt F Tags: Biomech Model Mechanobiol Source Type: research

Image-based analysis and simulation of the effect of platelet storage temperature on clot mechanics under uniaxial strain.
The objective of this work is to delineate the relationship between morphological characteristics and mechanical response of clot networks. We examined scanning electron microscope images of clots prepared from fresh apheresis platelets, and from apheresis platelets stored for 5 days at room temperature or at 4 °C, suspended in pooled plasma. Principal component analysis of nine different morphometric parameters revealed that a single principal component (PC1) can distinguish the effect of platelet storage on clot ultrastructure. Finite element analysis of clot response to uniaxial strain was used to map the ...
Source: Biomechanics and Modeling in Mechanobiology - July 16, 2019 Category: Biomedical Science Authors: Lee SJ, Nguyen DM, Grewal HS, Puligundla C, Saha AK, Nair PM, Cap AP, Ramasubramanian AK Tags: Biomech Model Mechanobiol Source Type: research

The influence of an extra-articular implant on bone remodelling of the knee joint.
Abstract Bone remodelling is a crucial feature of maintaining healthy bones. The loading conditions on the bones are one of the key aspects which affect the bone remodelling cycle. Many implants, such as hip and knee implants, affect the natural loading conditions and hence influence bone remodelling. Theoretical and numerical methods, such as adaptive bone remodelling, can be used to investigate how an implant affects bone mineral density (BMD). This research aimed to study the influence of an extra-articular implant on bone remodelling of the knee joint using adaptive bone remodelling. Initially, a finite elemen...
Source: Biomechanics and Modeling in Mechanobiology - July 12, 2019 Category: Biomedical Science Authors: Saeidi M, Gubaua JE, Kelly P, Kazemi M, Besier T, Dicati GWO, Pereira JT, Neitzert T, Ramezani M Tags: Biomech Model Mechanobiol Source Type: research

Three-dimensional analysis of the thoracic aorta microscopic deformation during intraluminal pressurization.
Abstract The aorta is composed of various constituents with different mechanical properties. This heterogeneous structure implies non-uniform deformation in the aorta, which could affect local cell functions. The present study investigates 3D strains of the aorta at a cell scale induced by intraluminal pressurization. After resected mouse, thoracic aortas were stretched to their in vivo length, and the aortas were pressurized at 15, 40, 80, 120, and 160 mmHg. Images of autofluorescent light of elastin were captured under a two-photon microscope. From the movement of markers in elastic laminas (ELs) created by...
Source: Biomechanics and Modeling in Mechanobiology - July 11, 2019 Category: Biomedical Science Authors: Sugita S, Kato M, Wataru F, Nakamura M Tags: Biomech Model Mechanobiol Source Type: research

Effects of red blood cell aggregation on the blood flow in a symmetrical stenosed microvessel.
Abstract In order to figure out whether red blood cell (RBC) aggregation is beneficial or deleterious for the blood flow through a stenosis, fluid mechanics of a microvascular stenosis was examined through simulating the dynamics of deformable red blood cells suspended in plasma using dissipative particle dynamics. The spatial variation in time-averaged cell-free layer (CFL) thickness and velocity profiles indicated that the blood flow exhibits asymmetry along the flow direction. The RBC accumulation occurs upstream the stenosis, leading to a thinner CFL and reduced flow velocity. Therefore, the emergence of steno...
Source: Biomechanics and Modeling in Mechanobiology - July 11, 2019 Category: Biomedical Science Authors: Xiao LL, Lin CS, Chen S, Liu Y, Fu BM, Yan WW Tags: Biomech Model Mechanobiol Source Type: research

Optical coherence tomography-based patient-specific coronary artery reconstruction and fluid-structure interaction simulation.
This study suggests that OCT-based FSI model may be useful for plaque vulnerability assessment and it may be critical to perform the FSI simulation if an accurate WSS value is required. PMID: 31292774 [PubMed - as supplied by publisher] (Source: Biomechanics and Modeling in Mechanobiology)
Source: Biomechanics and Modeling in Mechanobiology - July 10, 2019 Category: Biomedical Science Authors: Wang J, Paritala PK, Mendieta JB, Komori Y, Raffel OC, Gu Y, Li Z Tags: Biomech Model Mechanobiol Source Type: research

Mechanical and microstructural changes of skeletal muscle following immobilization and/or stroke.
Abstract Patient management following a stroke currently represents a medical challenge. The presented study investigates the effect of immobilization on skeletal muscles in short positions after a stroke. A rat model was implemented in order to compare four situations within 14 days including control group, immobilization of one forelimb without stroke, stroke without immobilization and stroke with immobilization of the paretic forelimb. To analyze the changes of the mechanical properties of the passive skeletal muscle, the biological tissue is assumed to behave as a visco-hyperelastic and incompressible mat...
Source: Biomechanics and Modeling in Mechanobiology - July 6, 2019 Category: Biomedical Science Authors: Jalal N, Gracies JM, Zidi M Tags: Biomech Model Mechanobiol Source Type: research

Co-localization of microstructural damage and excessive mechanical strain at aortic branches in angiotensin-II-infused mice.
Abstract Animal models of aortic aneurysm and dissection can enhance our limited understanding of the etiology of these lethal conditions particularly because early-stage longitudinal data are scant in humans. Yet, the pathogenesis of often-studied mouse models and the potential contribution of aortic biomechanics therein remain elusive. In this work, we combined micro-CT and synchrotron-based imaging with computational biomechanics to estimate in vivo aortic strains in the abdominal aorta of angiotensin-II-infused ApoE-deficient mice, which were compared with mouse-specific aortic microstructural damage inferred ...
Source: Biomechanics and Modeling in Mechanobiology - July 4, 2019 Category: Biomedical Science Authors: Aslanidou L, Ferraro M, Lovric G, Bersi MR, Humphrey JD, Segers P, Trachet B, Stergiopulos N Tags: Biomech Model Mechanobiol Source Type: research

Captopril treatment during development alleviates mechanically induced aortic remodeling in newborn elastin knockout mice.
Abstract Deposition of elastin and collagen in the aorta correlates with increases in blood pressure and flow during development, suggesting that the aorta adjusts its mechanical properties in response to hemodynamic stresses. Elastin knockout (Eln-/-) mice have high blood pressure and pathological remodeling of the aorta and die soon after birth. We hypothesized that decreasing blood pressure in Eln-/- mice during development may reduce hemodynamic stresses and alleviate pathological remodeling of the aorta. We treated Eln+/+ and Eln-/- mice with the anti-hypertensive medication captopril throughout embryonic dev...
Source: Biomechanics and Modeling in Mechanobiology - July 3, 2019 Category: Biomedical Science Authors: Kim J, Cocciolone AJ, Staiculescu MC, Mecham RP, Wagenseil JE Tags: Biomech Model Mechanobiol Source Type: research

Numerical study on the dynamics of primary cilium in pulsatile flows by the immersed boundary-lattice Boltzmann method.
Abstract An explicit immersed boundary-lattice Boltzmann method is applied to numerically investigate the dynamics of primary cilium in pulsatile blood flows with two-way fluid-structure interaction considered. To well characterize the effect of cilium basal body on cilium dynamics, the cilium base is modeled as a nonlinear rotational spring attached to the cilium's basal end as proposed by Resnick (Biophys J 109:18-25, 2015. https://doi.org/10.1016/j.bpj.2015.05.031 ). After several careful validations, the fluid-cilium interaction system is investigated in detail at various pulsatile flow conditions that are cha...
Source: Biomechanics and Modeling in Mechanobiology - June 29, 2019 Category: Biomedical Science Authors: Cui J, Liu Y, Fu BM Tags: Biomech Model Mechanobiol Source Type: research

Predictive prosthetic socket design: part 1-population-based evaluation of transtibial prosthetic sockets by FEA-driven surrogate modelling.
In this study, a parametric model was created, informed by variation in (i) population-driven residuum shape morphology, (ii) soft tissue compliance and (iii) prosthetic socket design. A Kriging surrogate model was fitted to the response of the analyses across the design space enabling prediction for new residual limb morphologies and socket designs. It was predicted that morphological variability and prosthetic socket design had a substantial effect on socket-limb interfacial pressure and shear conditions as well as sub-dermal soft tissue strains. These relationships were investigated with a higher resolution of anat...
Source: Biomechanics and Modeling in Mechanobiology - June 29, 2019 Category: Biomedical Science Authors: Steer JW, Worsley PR, Browne M, Dickinson AS Tags: Biomech Model Mechanobiol Source Type: research

A novel ischemia reperfusion injury hereditary tissue model for pressure ulcers progression.
We present a generalized IRI model considering external loading, dynamic tissue healing capacity, accumulating mechanical and reperfusion-mediated damages and competing repair processes of saturating nature. Reperfusion depends on strain and strain rate to enhance loading history sensitivity. Tissue-specific ulceration susceptibility is assumed dependent on variable accumulated damage. We study damage evolution under cyclic loading having several strain expulsion profiles and demonstrate load relief history has critical impact on PU progression. Abrupt load removal generally follows existing models representing extreme rep...
Source: Biomechanics and Modeling in Mechanobiology - June 27, 2019 Category: Biomedical Science Authors: Bullkich E, Kimmel E, Golan S Tags: Biomech Model Mechanobiol Source Type: research

Using machine learning to characterize heart failure across the scales.
Abstract Heart failure is a progressive chronic condition in which the heart undergoes detrimental changes in structure and function across multiple scales in time and space. Multiscale models of cardiac growth can provide a patient-specific window into the progression of heart failure and guide personalized treatment planning. Yet, the predictive potential of cardiac growth models remains poorly understood. Here, we quantify predictive power of a stretch-driven growth model using a chronic porcine heart failure model, subject-specific multiscale simulation, and machine learning techniques. We combine hierarchical...
Source: Biomechanics and Modeling in Mechanobiology - June 25, 2019 Category: Biomedical Science Authors: Peirlinck M, Sahli Costabal F, Sack KL, Choy JS, Kassab GS, Guccione JM, De Beule M, Segers P, Kuhl E Tags: Biomech Model Mechanobiol Source Type: research

Microstructural characterization of annulus fibrosus by ultrasonography: a feasibility study with an in vivo and in vitro approach.
Abstract The main function of the intervertebral disc is biomechanical function, since it must resist repetitive high loadings, while giving the spine its flexibility and protecting the spinal cord from over-straining. It partially owes its mechanical characteristics to the lamellar architecture of its outer layer, the annulus fibrosus. Today, no non-invasive means exist to characterize annulus lamellar structure in vivo. The aim of this work was to test the feasibility of imaging annulus fibrosus microstructure in vivo with ultrasonography. Twenty-nine healthy adolescents were included. Ultrasonographies of L3-L4...
Source: Biomechanics and Modeling in Mechanobiology - June 20, 2019 Category: Biomedical Science Authors: Langlais T, Desprairies P, Pietton R, Rohan PY, Dubousset J, Meakin JR, Winlove PC, Vialle R, Skalli W, Vergari C Tags: Biomech Model Mechanobiol Source Type: research

Reduced-order modeling of blood flow for noninvasive functional evaluation of coronary artery disease.
We present a novel computational approach, based on a parametrized reduced-order model, for accelerating the calculation of pressure drop along blood vessels. Vessel lumina are defined by a geometric parametrization using the discrete empirical interpolation method on control points located on the surface of the vessel. Hemodynamics are then computed using a reduced-order representation of the parametrized three-dimensional unsteady Navier-Stokes and continuity equations. The reduced-order model is based on an offline-online splitting of the solution process, and on the projection of a finite volume full-order model on a l...
Source: Biomechanics and Modeling in Mechanobiology - June 19, 2019 Category: Biomedical Science Authors: Buoso S, Manzoni A, Alkadhi H, Plass A, Quarteroni A, Kurtcuoglu V Tags: Biomech Model Mechanobiol Source Type: research

Linking microvascular collapse to tissue hypoxia in a multiscale model of pressure ulcer initiation.
Abstract Pressure ulcers are devastating injuries that disproportionately affect the older adult population. The initiating factor of pressure ulcers is local ischemia, or lack of perfusion at the microvascular level, following tissue compression against bony prominences. In turn, lack of blood flow leads to a drop in oxygen concentration, i.e, hypoxia, that ultimately leads to cell death, tissue necrosis, and disruption of tissue continuity. Despite our qualitative understanding of the initiating mechanisms of pressure ulcers, we are lacking quantitative knowledge of the relationship between applied pressure, ski...
Source: Biomechanics and Modeling in Mechanobiology - June 15, 2019 Category: Biomedical Science Authors: Sree VD, Rausch MK, Tepole AB Tags: Biomech Model Mechanobiol Source Type: research

Patient-specific predictions of aneurysm growth and remodeling in the ascending thoracic aorta using the homogenized constrained mixture model.
Abstract In its permanent quest of mechanobiological homeostasis, our vasculature significantly adapts across multiple length and timescales in various physiological and pathological conditions. Computational modeling of vascular growth and remodeling (G&R) has significantly improved our insights into the mechanobiological processes of diseases such as hypertension or aneurysms. However, patient-specific computational modeling of ascending thoracic aortic aneurysm (ATAA) evolution, based on finite element models (FEM), remains a challenging scientific problem with rare contributions, despite the major signific...
Source: Biomechanics and Modeling in Mechanobiology - June 14, 2019 Category: Biomedical Science Authors: Mousavi SJ, Farzaneh S, Avril S Tags: Biomech Model Mechanobiol Source Type: research