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Biomechanics and Modeling in Mechanobiology

J J Vaca-González, M Moncayo-Donoso, J M Guevara, Y Hata, S J Shefelbine, D A Garzón-Alvarado
Long bone formation starts early during embryonic development through a process known as endochondral ossification. This is a highly regulated mechanism that involves several mechanical and biochemical factors. Because long bone development is an extremely complex process, it is unclear how biochemical regulation is affected when dynamic loads are applied, and also how the combination of mechanical and biochemical factors affect the shape acquired by the bone during early development. In this study, we develop a mechanobiological model combining: (1) a reaction-diffusion system to describe the biochemical process and (2) a poroelastic model to determine the stresses and fluid flow due to loading...
January 10, 2018: Biomechanics and Modeling in Mechanobiology
Rodrigo Méndez Rojano, Simon Mendez, Franck Nicoud
Thrombosis is a major concern in blood-coated medical devices. Contact activation, which is the initial part of the coagulation cascade in device-related thrombosis, is not considered in current thrombus formation models. In the present study, pro-coagulant reactions including the contact activation system are coupled with a fluid solver in order to evaluate the potential of the contact system to initiate thrombin production. The biochemical/fluid model is applied to a backward-facing step configuration, a flow configuration that frequently appears in medical devices...
January 4, 2018: Biomechanics and Modeling in Mechanobiology
David Elad, Uri Zaretsky, Sharon Avraham, Ruthie Gotlieb, Michael Wolf, Itzhak Katra, Shlomo Sarig, Eli Zaady
Dust storms are common phenomena in many parts of the world, and significantly increase the level of atmospheric particulate matter (PM). The soil-derived dust is a mixture of organic and inorganic particles and even remnants of pesticides from agricultural areas nearby. The risk of human exposure to atmospheric dust is well documented, but very little is known on the impact of inhaled PM on the biological lining of the nasal cavity, which is the natural filter between the external environment and the respiratory tract...
January 4, 2018: Biomechanics and Modeling in Mechanobiology
Mohammad M Faghih, M Keith Sharp
Hemolysis is a persistent issue with blood-contacting devices. Many experimental and theoretical contributions over the last few decades have increased insight into the mechanisms of hemolysis in both laminar and turbulent flows, with the ultimate goal of developing a comprehensive, mechanistic hemolysis model. Many models assume that hemolysis scales with a resultant, scalar stress representing all components of the fluid stress tensor. This study critically evaluates this scalar stress hypothesis by calculating the response of the red blood cell membrane to different types of fluid stress (laminar shear and extension, and three turbulent shear and extension cases), each with the same scalar stress...
January 3, 2018: Biomechanics and Modeling in Mechanobiology
Alexander Synek, Dieter H Pahr
A micro-finite element-based method to estimate the bone loading history based on bone architecture was recently presented in the literature. However, a thorough investigation of the parameter sensitivity and plausibility of this method to predict joint loads is still missing. The goals of this study were (1) to analyse the parameter sensitivity of the joint load predictions at one proximal femur and (2) to assess the plausibility of the results by comparing load predictions of ten proximal femora to in vivo hip joint forces measured with instrumented prostheses (available from www...
December 30, 2017: Biomechanics and Modeling in Mechanobiology
Akinjide R Akintunde, Kristin S Miller
Tendon injuries are common to all ages. Injured tendons typically do not recover full functionality. The amount and organization of tendon constituents dictate their mechanical properties. The impact of changes in these constituents during (patho)physiologic processes (e.g., aging and healing) are not fully understood. Toward this end, microstructurally motivated strain energy functions (SEFs) offer insight into underlying mechanisms of age-dependent healing. Several SEFs have been adapted for tendon; however, most are phenomenological...
December 12, 2017: Biomechanics and Modeling in Mechanobiology
Pablo Gómez, Anne Schützenberger, Stefan Kniesburges, Christopher Bohr, Michael Döllinger
This study presents a framework for a direct comparison of experimental vocal fold dynamics data to a numerical two-mass-model (2MM) by solving the corresponding inverse problem of which parameters lead to similar model behavior. The introduced 2MM features improvements such as a variable stiffness and a modified collision force. A set of physiologically sensible degrees of freedom is presented, and three optimization algorithms are compared on synthetic vocal fold trajectories. Finally, a total of 288 high-speed video recordings of six excised porcine larynges were optimized to validate the proposed framework...
December 11, 2017: Biomechanics and Modeling in Mechanobiology
Quan Shi, Qiang Chen, Nicola Pugno, Zhi-Yong Li
Implantation of biodegradable scaffold is considered as a promising method to treat bone disorders, but knowledge of the dynamic bone repair process is extremely limited. In this study, based on the representative volume cell of a periodic scaffold, the influence of rehabilitation exercise duration per day on the bone repair was investigated by a computational framework. The framework coupled scaffold degradation and bone remodeling. The scaffold degradation was described by a function of stochastic hydrolysis independent of mechanical stimulation, and the bone formation was remodeled by a function of the mechanical stimulation, i...
December 8, 2017: Biomechanics and Modeling in Mechanobiology
Jeyendran Nadarasa, Caroline Deck, Frank Meyer, Nicolas Bourdet, Jean-Sébastien Raul, Rémy Willinger
Retinal hemorrhages (RH) are among injuries sustained by a large number of shaken baby syndrome victims, but also by a small proportion of road accident victims. In order to have a better understanding of the underlying of RH mechanisms, we aimed to develop a complete human eye and orbit finite element model. Five occipital head impacts, at different heights and on different surfaces, and three shaking experiments were conducted with a 6-week-old dummy (Q0 dummy). This allowed obtaining a precise description of the motion in those two specific situations, which was then used as input for the eye model simulation...
December 5, 2017: Biomechanics and Modeling in Mechanobiology
M H Korayem, S Shahali, Z Rastegar
Plasma membrane of most cells is not smooth. The surfaces of both small and large micropermeable cells are folded and corrugated which makes mammalian cells to have a larger membrane surface than the supposed ideal mode, that is, the smooth sphere of the same volume. Since cancer is an anthropic disease, cancer cells tend to have a larger membrane area than normal cells. Therefore, cancer cells have higher folding factor and larger radius than normal and healthy cells. On the other hand, the prevalence of breast cancer has prompted researchers to improve the treatment options raised for the disease in the past...
December 2, 2017: Biomechanics and Modeling in Mechanobiology
Emma Lejeune, Christian Linder
Understanding the mechanical behavior of multicellular monolayers and spheroids is fundamental to tissue culture, organism development, and the early stages of tumor growth. Proliferating cells in monolayers and spheroids experience mechanical forces as they grow and divide and local inhomogeneities in the mechanical microenvironment can cause individual cells within the multicellular system to grow and divide at different rates. This differential growth, combined with cell division and reorganization, leads to residual stress...
December 2, 2017: Biomechanics and Modeling in Mechanobiology
Xinyao Zhu, Srdjan Cirovic, Aliah Shaheen, Wei Xu
In this study, atomic force microscopy (AFM) is used to investigate the alterations of the poroelastic properties of hepatocellular carcinoma (SMMC-7721) cells treated with fullerenol. The SMMC-7721 cells were subject to AFM-based creep tests, and a corresponding poroelastic indentation model was used to determine the poroelastic parameters by curve fitting. Comparative analyses indicated that the both permeability and diffusion of fullerenol-treated cells increased significantly while their elastic modulus decreased by a small amount...
December 1, 2017: Biomechanics and Modeling in Mechanobiology
A Campos Marín, M Brunelli, D Lacroix
The combination of perfusion bioreactors with porous scaffolds is beneficial for the transport of cells during cell seeding. Nonetheless, the fact that cells penetrate into the scaffold pores does not necessarily imply the interception of cells with scaffold substrate and cell attachment. An in vitro perfusion system was built to relate the selected flow rate with seeding efficiency. However, the in vitro model does not elucidate how the flow rate affects the transport and deposition of cells onto the scaffold...
November 29, 2017: Biomechanics and Modeling in Mechanobiology
Debanjan Mukherjee, Shawn C Shadden
A hybrid, multiscale, particle-continuum numerical method is developed for resolving the interaction of a realistic thrombus geometry with unsteady hemodynamics typically occurring within large arteries. The method is based on a discrete particle/element description of the thrombus, coupled to blood flow using a fictitious domain finite element method. The efficacy of the discrete element approach in representing thrombi with arbitrary aggregate morphology and microstructure is demonstrated. The various features of the method are illustrated using a series of numerical experiments with a model system consisting of an occlusion embedded in a channel...
November 27, 2017: Biomechanics and Modeling in Mechanobiology
Christina J Stender, Evan Rust, Peter T Martin, Erica E Neumann, Raquel J Brown, Trevor J Lujan
Ligament mechanical behavior is primarily regulated by fibrous networks of type I collagen. Although these fibrous networks are typically highly aligned, healthy and injured ligament can also exhibit disorganized collagen architecture. The objective of this study was to determine whether variations in the collagen fibril network between neighboring ligaments can predict observed differences in mechanical behavior. Ligament specimens from two regions of bovine fetlock joints, which either exhibited highly aligned or disorganized collagen fibril networks, were mechanically tested in uniaxial tension...
November 24, 2017: Biomechanics and Modeling in Mechanobiology
Petri Tanska, Petro Julkunen, Rami K Korhonen
Cartilage defects are a known risk factor for osteoarthritis. Estimation of structural changes in these defects could help us to identify high risk defects and thus to identify patients that are susceptible for the onset and progression of osteoarthritis. Here, we present an algorithm combined with computational modeling to simulate the disorganization of collagen fibril network in injured cartilage. Several potential triggers for collagen disorganization were tested in the algorithm following the assumption that disorganization is dependent on the mechanical stimulus of the tissue...
November 24, 2017: Biomechanics and Modeling in Mechanobiology
Donnacha J McGrath, Anja Lena Thiebes, Christian G Cornelissen, Barry O'Brien, Stefan Jockenhoevel, Mark Bruzzi, Peter E McHugh
Tracheobronchial stents are used to restore patency to stenosed airways. However, these devices are associated with many complications such as stent migration, granulation tissue formation, mucous plugging and stent strut fracture. Of these, granulation tissue formation is the complication that most frequently requires costly secondary interventions. In this study a biomechanical lung modelling framework recently developed by the authors to capture the lung in-vivo stress state under physiological loading is employed in conjunction with ovine pre-clinical stenting results and device experimental data to evaluate the effect of stent interaction on granulation tissue formation...
November 24, 2017: Biomechanics and Modeling in Mechanobiology
T I Zohdi, R Krone
Low-intensity, unfocused, ultrasound-induced diathermy can produce undesired temperature increases at the interface of adjacent tissues within the body; particularly, at the interface of soft tissue and bone. This study provides a computational framework for predicting an upper bound on the temperature profile within a multiphase system composed of gel pad (water), tissue and bone from an input of acoustic energy, at frequencies and power levels consistent with applications of therapeutic hyperthermia. The model consists of solving a (one-dimensional) spatially discretized bioheat transfer equation via finite-difference method and updating the solution in time with a forward-Euler scheme...
November 22, 2017: Biomechanics and Modeling in Mechanobiology
Faris Tarlochan, Hassan Mehboob, Ali Mehboob, Seung-Hwan Chang
Cementless hip prostheses with porous outer coating are commonly used to repair the proximally damaged femurs. It has been demonstrated that stability of prosthesis is also highly dependent on the bone ingrowth into the porous texture. Bone ingrowth is influenced by the mechanical environment produced in the callus. In this study, bone ingrowth into the porous structure was predicted by using a mechano-regulatory model. Homogenously distributed pores (200 and 800 [Formula: see text]m in diameter) and functionally graded pores along the length of the prosthesis were introduced as a porous coating...
November 22, 2017: Biomechanics and Modeling in Mechanobiology
J Menacho, L Rotllant, J J Molins, G Reyes, A A García-Granada, M Balcells, J Martorell
The present study examines the possibility of attenuating blood pulses by means of introducing prosthetic viscoelastic materials able to absorb energy and damp such pulses. Vascular prostheses made of polymeric materials modify the mechanical properties of blood vessels. The effect of these materials on the blood pulse propagation remains to be fully understood. Several materials for medical applications, such as medical polydimethylsiloxane or polytetrafluoroethylene, show viscoelastic behavior, modifying the original vessel stiffness and affecting the propagation of blood pulses...
November 22, 2017: Biomechanics and Modeling in Mechanobiology
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