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Journal of Biomechanical Engineering

Nitin Kumar Sharma, M D Sarker, Saman Naghieh, Daniel X B Chen
Bone is a complex material that exhibits an amount of plasticity before bone fracture takes place, where the non-linear relationship between stress and strain is of importance to understanding the mechanism behind the fracture. This brief presents our study on the examination of the stress-stain relationship of bovine femoral cortical bone and the relationship representation by employing the Ramberg-Osgood (R-O) equation. Samples were taken and prepared from different locations (upper, middle and lower) of bone diaphysis and were then subjected to the uniaxial tensile tests under longitudinal and transverse loading conditions, respectively...
February 19, 2019: Journal of Biomechanical Engineering
Xuedong Zhai, Eric A Nauman, Yizhou Nie, Hangjie Liao, Roy Lycke, Weinong Chen
We experimentally determined the tensile stress-strain response of human muscle along fiber direction and compressive stress-strain response transverse to fiber direction at intermediate strain rates. A hydraulically driven materials testing system with a dynamic testing mode was used to perform the tensile and compressive experiments on human muscle tissue. Experiments at quasi-static strain rates were also conducted to investigate the strain-rate effects over a wider range. The specimens were loaded under stress equilibrium state for both the tensile and compressive experiments...
February 19, 2019: Journal of Biomechanical Engineering
Ehab Akram Tamimi, Diana Catalina Ardila, Burt D Ensley, Robert S Kellar, Jonathan Vande Geest
Coronary artery bypass grafts used to treat coronary artery disease often fail due to compliance mismatch. In this study, we have developed an experimental/computational approach to fabricate an acellular biomimetic hybrid tissue engineered vascular graft composed of alternating layers of electrospun porcine gelatin/polycaprolactone (PCL) and human tropoelastin/PCL blends with the goal of compliance-matching to rat abdominal aorta, while maintaining specific geometrical constraints. Polymeric blends at three different gelatin:PCL (G:PCL) and tropoelastin:PCL (T:PCL) ratios (80:20, 50:50 and 20:80) were mechanically characterized...
February 19, 2019: Journal of Biomechanical Engineering
Bo Jiang, Vikas Thondapu, Eric Poon, Peter Barlis, Andrew Ooi
Incomplete stent apposition (ISA) is one of the causes leading to post-stent complications, which can be found when an undersized or under-expanded stent is deployed at lesions. Previous research efforts have focused on ISA in idealized coronary arterial geometry with circular cross-sections. However, arterial cross-section eccentricity plays an important role in both location and severity of ISA. Computational fluid dynamics (CFD) simulations are carried out to systematically study the effects of ISA in arteries with elliptical cross-sections, as such stents are partially embedded on the minor axis sides of the ellipse and malapposed elsewhere...
February 19, 2019: Journal of Biomechanical Engineering
Louis Soslowsky
This paper generally follows the presentation I gave at the 2018 World Congress of Biomechanics in Dublin, Ireland in recognition of the receipt of the H.R. Lissner Medal from the American Society of Mechanical Engineers. It will begin discussing my family, followed by my undergraduate and graduate experiences at Columbia University. I will then review some activities during my first faculty position at the University of Michigan and then continue on with my experiences over the past 20+ years at the University of Pennsylvania...
February 19, 2019: Journal of Biomechanical Engineering
Liang Zhu, Dr John Bischof
The Journal of Biomechanical Engineering has contributed to biomechanical engineering field since 1977. To honor papers published at least 30 years that have had a long-lasting impact on the field, the Editors now recognize "Legacy Papers." The journal is pleased to present the following paper as this year's Legacy Paper: "A New Simplified Bioheat Equation for the Effect of Blood Flow on Local Average Tissue Temperature" by S. Weinbaum and L. Jiji, ASME Journal of Biomechanical Engineering 107: 131-139, 1985...
February 19, 2019: Journal of Biomechanical Engineering
Wafaa Karaki, Carlos Lopez, Fnu Rahul, Dr Diana-Andra Borca-Tasciuc, Suvranu De
Electrosurgical procedures are ubiquitously used in surgery. The commonly used power modes, including the coagulation and blend modes, utilize non-sinusoidal or modulated current waveforms. For the same power setting, the coagulation, blend and pure cutting modes have different heating and thermal damage outcomes due to the frequency dependence of electrical conductivity of soft hydrated tissues. In this paper, we propose a multi-physics model of soft tissues to account for the effects of multi-frequency electrosurgical power modes within the framework of a continuum thermomechanical model based on mixture theory...
February 19, 2019: Journal of Biomechanical Engineering
Jessica E Wagenseil
Allometric scaling laws relate physiologic parameters to body weight. Genetically modified mice allow investigation of allometric scaling laws when fundamental cardiovascular components are altered. Elastin haploinsufficient (Eln+/-) mice have reduced elastin amounts and fibulin-5 knockout (Fbln5-/-) mice have compromised elastic fiber integrity in the large arteries which may alter cardiovascular scaling laws. Previously published echocardiography data used to investigate aortic and left ventricular function in Eln+/- and Fbln5-/- mice throughout postnatal development and early adulthood were reanalyzed to determine cardiovascular scaling laws...
February 7, 2019: Journal of Biomechanical Engineering
Chi Zhu, Jung-Hee Seo, Rajat Mittal
In this study, coupled hemodynamic-acoustic simulations are employed to study the generation and propagation of murmurs associated with aortic stenoses where the aorta with a stenosed aortic valve is modeled as a curved pipe with a constriction near the inlet. The hemodynamics of the post-stenotic flow is investigated in detail in our previous numerical study. The temporal history of the pressure on the aortic lumen is recorded during the hemodynamic study and used as the murmur source in the acoustic simulations...
February 7, 2019: Journal of Biomechanical Engineering
Bardiya Akhbari, Amy Morton, Douglas Moore, Arnold-Peter C Weiss, Scott W Wolfe, Joseph Crisco
Total Wrist Arthroplasty (TWA) for improving the functionality of severe wrist joint pathology has not had the same success, in parameters such as motion restoration and implant survival, as hip, knee, and shoulder arthroplasty. These other arthroplasties have been studied extensively, including the use of biplane videoradiography (BVR) that has allowed investigators to study the in-vivo motion of the total joint replacement during dynamic activities. The wrist has not been a previous focus, and utilization of BVR for wrist arthroplasty presents unique challenges due to the design characteristics of TWAs...
February 7, 2019: Journal of Biomechanical Engineering
Agnese Piovesan, Francesca Berti, Tomaso Villa, Giancarlo Pennati, Luigi La Barbera
Posterior fixation with contoured rods is an estabilished methodology for the treatment of spinal deformities. Both uniform industrial preforming and intraoperative contouring introduce tensile and compressive plastic deformations, respectively, at the concave and at the convex sides of the rod. The purpose of this study is to develop a validated numerical framework capable of predicting how the fatigue behavior of contoured spinal rods is affected by residual stresses when loaded in lordotic and kyphotic configurations...
February 7, 2019: Journal of Biomechanical Engineering
Vitaly Kheyfets, Uyen Truong, Dunbar Ivy, Robin Shandas
Pulmonary hypertension (PH) is a degenerative disease characterized by progressively increased right ventricular (RV) afterload that leads to ultimate functional decline [1]. Recent observational studies have documented a decrease in left ventricular (LV) torsion during ejection, with preserved LV ejection fraction (EF) in pediatric and adult PH patients [2-4]. The objective of this study was to develop a computational model of the bi-ventricular heart and use it to evaluate changes in LV torsion mechanics in response to mechanical, structural, and hemodynamic changes in the RV free-wall...
February 4, 2019: Journal of Biomechanical Engineering
Andrea Zonnino, Fabrizio Sergi
The control of joint stiffness is a fundamental mechanism used to control human movements. While many studies have observed how stiffness is modulated for tasks involving shoulder and elbow motion, a limited amount of knowledge is available for wrist movements, though the wrist plays a crucial role in manipulation. We have developed a computational framework based on a realistic musculoskeletal model, which al to calculate the passive and active components of the wrist joint stiffness. We first used the framework to validate the musculoskeletal model against experimental measurements of the wrist joint stiffness, and then to study the contribution of different muscle groups to the passive joint stiffness...
February 4, 2019: Journal of Biomechanical Engineering
Mirit Sharabi, Aviad Levi-Sasson, Roza Wolfson, Kelly R Wade, Fabio Galbusera, Dafna Benayahu, Hans-Joachim Wilke, Rami Haj-Ali
The annulus fibrosus (AF) of the intervertebral disc (IVD) consists of a set of concentric layers composed of a primary circumferential collagen fibers arranged in an alternating oblique orientation. Moreover, there exists an additional secondary set of radial translamellar collagen fibers which connects the concentric layers, creating an entangled fiber network. The aim of this study is to investigate the mechanical role of the radial fiber network. Towards that goal, a three-dimensional finite-element model of the L3-L4 spinal segment was generated, and calibrated to axial compression and pure moment loading...
February 4, 2019: Journal of Biomechanical Engineering
Nurdan Bilgin, M Kemal Ozgoren
This study aims to estimate the control law employed by the CNS (Central Nervous System) to keep a person in balance after a sudden disturbance. For this aim, several experiments were carried out, in which the subjects were perturbed sagittally by using a single-axis tilt-platform and their motions were recorded with appropriate sensors. The analysis of the experimental results leads to the conjecture that the CNS commands the muscular actuators of the human joints according to a PD control law but it updates the control gains and the set points continuously...
February 4, 2019: Journal of Biomechanical Engineering
Ji Wang, Bin Zhou, Yizhong Hu, Zhendong Zhang, Y Eric Yu, Shashank Nawathe, Kyle K Nishiyama, Tony M Keaveny, Elizabeth Shane, X Edward Guo
The high-resolution peripheral quantitative computed tomography (HRpQCT) provides unprecedented visualization of bone microstructure and the basis for constructing patient-specific micro-finite element (µFE) models. Based on HRpQCT images, we have developed a plate rod µFE (PRµFE) method for whole bone segments using individual trabecula segmentation (ITS) and an adaptive cortical meshing technique. In contrast to the conventional voxel approach, the complex microarchitecture of the trabecular compartment is simplified into shell and beam elements based on the trabecular plate-and-rod configuration...
January 31, 2019: Journal of Biomechanical Engineering
Ethan Kung, Masoud Farahmand, Akash Gupta
Significant advances in biomedical science often leverage powerful computational and experimental modeling platforms. We present a framework named "PSCOPE" that can capitalize the strengths of both types of platforms in a hybrid model. PSCOPE uses an iterative method to couple an in-vitro mock circuit to a lumped-parameter numerical simulation of physiology, obtaining closed-loop feedback between the two. We first compared results of Fontan graft obstruction scenarios modeled using both PSCOPE and an established multiscale computational fluid dynamics method; the normalized root-mean-square error values of important physiologic parameters were between 0...
January 30, 2019: Journal of Biomechanical Engineering
Sarah E Duclos, Arthur J Michalek
Predicting the mechanical behavior of the intervertebral disc (IVD) in health and in disease requires accurate spatial mapping of its compressive mechanical properties. Previous studies confirmed that residual strains in the annulus fibrosus (AF) of the IVD, which result from non-uniform extracellular matrix deposition in response to in-vivo loads, vary by anatomical region (anterior, posterior, and lateral) and zone (inner, middle, and outer). We hypothesized that as the AF is composed of a nonlinear, anisotropic, viscoelastic material, the state of residual strain in the transverse plane would influence the apparent values of axial compressive properties...
January 23, 2019: Journal of Biomechanical Engineering
Hamed Avari, Kem A Rogers, Eric Savory
Cardiovascular diseases (CVDs) are the number one cause of death globally. Arterial endothelial cell (EC) dysfunction plays a key role in many of these CVDs, such as atherosclerosis. Blood flow-induced wall shear stress (WSS), among many other pathophysiological factors, is known to significantly contribute to EC dysfunction. The present study reports an in vitro investigation of the effect of quantified WSS on ECs, analyzing the EC morphometric parameters as well as cytoskeletal remodeling. The effects of four different flow cases (low steady laminar (LSL), medium steady laminar (MSL), non-zero-mean sinusoidal laminar (NZMSL) and laminar carotid (LCRD) waveforms) on EC area, perimeter, shape index (SI), angle of orientation, F-actin bundle remodeling and PECAM-1 localization were studied...
January 23, 2019: Journal of Biomechanical Engineering
Abhilash Awasthi, Rajneesh Sharma, Rajesh Ghosh
A multi-scale model for mineralized collagen fibril is proposed by taking into account the uncertainties associated with the geometrical properties of mineral phase and its distribution in the organic matrix. The asymptotic homogenization approach along with periodic boundary conditions has been used to derive the effective elastic moduli at two hierarchical length scales, namely: microfibril and mineralized collagen fibril. The uncertainties associated with the mineral plates have been directly included in the finite element mesh by randomly varying their sizes...
January 7, 2019: Journal of Biomechanical Engineering
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