Read by QxMD icon Read

Biomechanics and Modeling in Mechanobiology

C D Bertram, C Macaskill, M J Davis, J E Moore
Lymph is transported along collecting lymphatic vessels by intrinsic and extrinsic pumping. The walls have muscle of a type intermediate between blood-vascular smooth muscle and myocardium; a contracting segment between two valves (a lymphangion) constitutes a pump. This intrinsic mechanism is investigated ex vivo in isolated, spontaneously contracting, perfused segments subjected to controlled external pressures. The reaction to varying afterload is probed by slowly ramping up the outlet pressure until pumping fails...
July 11, 2017: Biomechanics and Modeling in Mechanobiology
Sven Nebelung, Manuel Post, Stefan Raith, Horst Fischer, Matthias Knobe, Benedikt Braun, Andreas Prescher, Markus Tingart, Johannes Thüring, Philipp Bruners, Holger Jahr, Christiane Kuhl, Daniel Truhn
The response to loading of human articular cartilage as assessed by magnetic resonance imaging (MRI) remains to be defined in relation to histology and biomechanics. Therefore, an MRI-compatible whole-knee joint loading device for the functional in situ assessment of cartilage was developed and validated in this study. A formalin-fixed human knee was scanned by computed tomography in its native configuration and digitally processed to create femoral and tibial bone models. The bone models were covered by artificial femoral and tibial articular cartilage layers in their native configuration using cartilage-mimicking polyvinyl siloxane...
July 6, 2017: Biomechanics and Modeling in Mechanobiology
Davide Gagliardi, Salah Naili, Christophe Desceliers, Vittorio Sansalone
Reliability of multiscale models of bone is related to the accuracy of the experimental information available on bone microstructure. X-ray-based imaging techniques allow to inspect bone structure and mineralization in vitro at the micrometre scale. However, spatial resolution achievable in vivo is much coarser and can produce blurry, uncertain information on bone microstructure. Working with uncertain data calls for new modelling paradigms able to propagate uncertainty through the scales. In this paper we investigate the effects of uncertain bone mineralization on the elastic coefficients of the bone matrix...
June 28, 2017: Biomechanics and Modeling in Mechanobiology
Kenneth I Aycock, Robert L Campbell, Frank C Lynch, Keefe B Manning, Brent A Craven
Embolus transport simulations are performed to investigate the dependence of inferior vena cava (IVC) filter embolus-trapping performance on IVC anatomy. Simulations are performed using a resolved two-way coupled computational fluid dynamics/six-degree-of-freedom approach. Three IVC geometries are studied: a straight-tube IVC, a patient-averaged IVC, and a patient-specific IVC reconstructed from medical imaging data. Additionally, two sizes of spherical emboli (3 and 5 mm in diameter) and two IVC orientations (supine and upright) are considered...
June 27, 2017: Biomechanics and Modeling in Mechanobiology
Patrik Wili, Ghislain Maquer, Jarunan Panyasantisuk, Philippe K Zysset
Micro-finite element ([Formula: see text]FE) analyses are often used to determine the apparent mechanical properties of trabecular bone volumes. Yet, these apparent properties depend strongly on the applied boundary conditions (BCs) for the limited size of volumes that can be obtained from human bones. To attenuate the influence of the BCs, we computed the yield properties of samples loaded via a surrounding layer of trabecular bone ("embedded configuration"). Thirteen cubic volumes (10.6 mm side length) were collected from [Formula: see text]CT reconstructions of human vertebrae and femora and converted into [Formula: see text]FE models...
June 22, 2017: Biomechanics and Modeling in Mechanobiology
Priti Yadav, Sandra J Shefelbine, Eva Pontén, Elena M Gutierrez-Farewik
Muscle and joint contact force influence stresses at the proximal growth plate of the femur and thus bone growth, affecting the neck shaft angle (NSA) and femoral anteversion (FA). This study aims to illustrate how different muscle groups' activation during gait affects NSA and FA development in able-bodied children. Subject-specific femur models were developed for three able-bodied children (ages 6, 7, and 11 years) using magnetic resonance images. Contributions of different muscle groups-hip flexors, hip extensors, hip adductors, hip abductors, and knee extensors-to overall hip contact force were computed...
June 22, 2017: Biomechanics and Modeling in Mechanobiology
Bingbing Nie, Jason L Forman, Alexander R Mait, John-Paul Donlon, Matthew B Panzer, Richard W Kent
Ligament sprains, defined as tearing of bands of fibrous tissues within ligaments, account for a majority of injuries to the foot and ankle complex in field-based sports. External rotation of the foot is considered the primary injury mechanism of syndesmotic ankle sprains with concomitant flexion and inversion/eversion associated with particular patterns of ligament trauma. However, the influence of the magnitude and direction of loading vectors to the ankle on the in situ stress state of the ligaments has not been quantified in the literature...
June 20, 2017: Biomechanics and Modeling in Mechanobiology
Hsiao-Ying Shadow Huang, Jiaqi Lu
Venous valve incompetence has been implicated in diseases ranging from chronic venous insufficiency (CVI) to intracranial venous hypertension. However, while the mechanical properties of venous valve leaflet tissues are central to CVI biomechanics and mechanobiology, neither stress-strain curves nor tangent moduli have been reported. Here, equibiaxial tensile mechanical tests were conducted to assess the tangent modulus, strength and anisotropy of venous valve leaflet tissues from bovine jugular veins. Valvular tissues were stretched to 60% strain in both the circumferential and radial directions, and leaflet tissue stress-strain curves were generated for proximal and distal valves (i...
June 19, 2017: Biomechanics and Modeling in Mechanobiology
H Rajabi, P Bazargan, A Pourbabaei, Sh Eshghi, A Darvizeh, S N Gorb, D Taylor, J-H Dirks
Locust wings are able to sustain millions of cycles of mechanical loading during the lifetime of the insect. Previous studies have shown that cross veins play an important role in delaying crack propagation in the wings. Do cross veins thus also influence the fatigue behaviour of the wings? Since many important fatigue parameters are not experimentally accessible in a small biological sample, here we use the finite element (FE) method to address this question numerically. Our FE model combines a linear elastic material model, a direct cyclic approach and the Paris law and shows results which are in very good agreement with previously reported experimental data...
June 17, 2017: Biomechanics and Modeling in Mechanobiology
Bo Yan, Juan Ren, Xi Zheng, Yue Liu, Qingze Zou
Study of the dynamic evolutions of cell viscoelasticity is important as during cell activities such as cell metastasis and invasion, the rheological behaviors of the cells also change dynamically, reflecting the biophysical and biochemical connections between the outer cortex and the intracellular structures. Although the time variations of the static modulus of cells have been investigated, few studies have been reported on the dynamic variations of the frequency-dependent viscoelasticity of cells. Measuring and monitoring such dynamic evolutions of cells at nanoscale can be challenging as the measurement needs to meet two objectives inherently contradictory to each other-the measurement must be broadband (to cover a large frequency spectrum) but also rapid (to capture the time-elapsed changes)...
June 8, 2017: Biomechanics and Modeling in Mechanobiology
Marco Fedele, Elena Faggiano, Luca Dedè, Alfio Quarteroni
In this paper, we propose a full computational framework to simulate the hemodynamics in the aorta including the valve. Closed and open valve surfaces, as well as the lumen aorta, are reconstructed directly from medical images using new ad hoc algorithms, allowing a patient-specific simulation. The fluid dynamics problem that accounts from the movement of the valve is solved by a new 3D-0D fluid-structure interaction model in which the valve surface is implicitly represented through level set functions, yielding, in the Navier-Stokes equations, a resistive penalization term enforcing the blood to adhere to the valve leaflets...
June 7, 2017: Biomechanics and Modeling in Mechanobiology
Lorenzo Marcucci, Carlo Reggiani, Arturo N Natali, Piero G Pavan
Muscles exhibit highly complex, multi-scale architecture with thousands of muscle fibers, each with different properties, interacting with each other and surrounding connective structures. Consequently, the results of single-fiber experiments are scarcely linked to the macroscopic or whole muscle behavior. This is especially true for human muscles where it would be important to understand of how skeletal muscles disorders affect patients' life. In this work, we developed a mathematical model to study how fast and slow muscle fibers, well characterized in single-fiber experiments, work and generate together force and displacement in muscle bundles...
June 5, 2017: Biomechanics and Modeling in Mechanobiology
Geoffrey G Handsfield, Bart Bolsterlee, Joshua M Inouye, Robert D Herbert, Thor F Besier, Justin W Fernandez
Determination of skeletal muscle architecture is important for accurately modeling muscle behavior. Current methods for 3D muscle architecture determination can be costly and time-consuming, making them prohibitive for clinical or modeling applications. Computational approaches such as Laplacian flow simulations can estimate muscle fascicle orientation based on muscle shape and aponeurosis location. The accuracy of this approach is unknown, however, since it has not been validated against other standards for muscle architecture determination...
June 2, 2017: Biomechanics and Modeling in Mechanobiology
Satoru Okuda, Mototsugu Eiraku
In cells, the molecular constituents of membranes are dynamically turned over by transportation from one membrane to another. This molecular turnover causes the membrane to shrink or expand by sensing the stress state within the cell, changing its morphology. At present, little is known as to how this turnover regulates the dynamic deformation of cellular membranes. In this study, we propose a new physical model by which molecular turnover is coupled with three-dimensional membrane deformation to explore mechanosensing roles of turnover in cellular membrane deformations...
May 29, 2017: Biomechanics and Modeling in Mechanobiology
B Zeybek, S Li, J W Fernandez, S Stapley, V V Silberschmidt, Y Liu
Proof-of-concept computational models were developed and applied as tools to gain insights into biomechanical interactions and variations of oxygen gradients of wounded tissue subject to negative pressure wound therapy (NPWT), following trans-femoral amputation. A macro-scale finite-element model of a lower limb was first developed based on computed tomography data, and distributions of maximum and minimum principal stress values we calculated for a region of interest (ROI). Then, the obtained results were applied iteratively as new sets of boundary conditions for a specific spatial position in a capillary sub-model...
May 28, 2017: Biomechanics and Modeling in Mechanobiology
S Jamaleddin Mousavi, Stéphane Avril
It is now a rather common approach to perform patient-specific stress analyses of arterial walls using finite-element models reconstructed from gated medical images. However, this requires to compute for every Gauss point the deformation gradient between the current configuration and a stress-free reference configuration. It is technically difficult to define such a reference configuration, and there is actually no guarantee that a stress-free configuration is physically attainable due to the presence of internal stresses in unloaded soft tissues...
May 23, 2017: Biomechanics and Modeling in Mechanobiology
Shakti N Menon, Cameron L Hall, Scott W McCue, D L Sean McElwain
The mechanical behaviour of solid biological tissues has long been described using models based on classical continuum mechanics. However, the classical continuum theories of elasticity and viscoelasticity cannot easily capture the continual remodelling and associated structural changes in biological tissues. Furthermore, models drawn from plasticity theory are difficult to apply and interpret in this context, where there is no equivalent of a yield stress or flow rule. In this work, we describe a novel one-dimensional mathematical model of tissue remodelling based on the multiplicative decomposition of the deformation gradient...
May 18, 2017: Biomechanics and Modeling in Mechanobiology
Young Kwan Kim, Yoshitaka Kameo, Sakae Tanaka, Taiji Adachi
To understand Wolff's law, bone adaptation by remodeling at the cellular and tissue levels has been discussed extensively through experimental and simulation studies. For the clinical application of a bone remodeling simulation, it is significant to establish a macroscopic model that incorporates clarified microscopic mechanisms. In this study, we proposed novel macroscopic models based on the microscopic mechanism of osteocytic mechanosensing, in which the flow of fluid in the lacuno-canalicular porosity generated by fluid pressure gradients plays an important role, and theoretically evaluated the proposed models, taking biological rationales of bone adaptation into account...
May 18, 2017: Biomechanics and Modeling in Mechanobiology
M Alipour, K Mithraratne, J Fernandez
The NZ white rabbit is the animal of choice for much experimental work due to its muscular frame and similar response to human diseases, and is one of the few mammals that have had their genome sequenced. However, continuum-level computational models of rabbit muscle detailing fibre architecture are limited in the literature, especially the triceps surae complex (gastrocnemius, plantaris and soleus), which has similar biomechanics and translatable findings to the human. This study presents a geometrical model of the rabbit triceps surae informed with diffusion-weighted imaging (DWI)-based fibres...
May 18, 2017: Biomechanics and Modeling in Mechanobiology
Francesc Levrero-Florencio, Krishnagoud Manda, Lee Margetts, Pankaj Pankaj
Being able to predict bone fracture or implant stability needs a proper constitutive model of trabecular bone at the macroscale in multiaxial, non-monotonic loading modes. Its macroscopic damage behaviour has been investigated experimentally in the past, mostly with the restriction of uniaxial cyclic loading experiments for different samples, which does not allow for the investigation of several load cases in the same sample as damage in one direction may affect the behaviour in other directions. Homogenised finite element models of whole bones have the potential to assess complicated scenarios and thus improve clinical predictions...
May 12, 2017: Biomechanics and Modeling in Mechanobiology
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"