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Journal of Biomechanical Engineering

Kelsey Bonilla, Adam Pardes, Benjamin Freedman, Louis J Soslowsky
Sex differences in the mechanical properties of different musculoskeletal tissues and their impact on tendon function and disease are becoming increasingly recognized. Tendon mechanical properties are influenced by the presence or absence of sex hormones and these effects appear to be tendon- or ligament-specific. The objective of this study was to determine how sex and hormone differences in rats affect supraspinatus tendon and muscle properties. We hypothesized that male supraspinatus tendons would have increased cross-sectional area but no differences in tendon material properties or muscle composition when compared to supraspinatus tendons from female or ovariectomized (OVX) female rats...
August 29, 2018: Journal of Biomechanical Engineering
David Molony, Jaekeun Park, Lei Zhou, Candace Fleischer, He-Ying Sun, Xiaoping Hu, John Oshinski, Habib Samady, Don P Giddens, Amir Rezvan
Animal models offer a flexible experimental environment for studying atherosclerosis. The mouse is the most commonly used animal, however, the underlying hemodynamics in larger animals such as the rabbit are far closer to that of humans. The aortic arch is a vessel with complex helical flow and highly heterogeneous shear stress patterns which may influence where atherosclerotic lesions form. A better understanding of intra-species flow variation and the impact of geometry on flow may improve our understanding of where disease forms...
August 21, 2018: Journal of Biomechanical Engineering
Nir Emuna, David Durban
Mechanical instability of soft tissues can either risk their normal function, or alternatively trigger patterning mechanisms during growth and morphogenesis processes. Unlike standard stability analysis of linear elastic bodies, for soft tissues undergoing large deformations it is imperative to account for the nonlinearities induced by the coupling between load and surface changes at onset of instability. The related issue of boundary conditions, in context of soft tissues, has hardly been addressed in the literature, with most of available research employing dead-load conditions...
August 16, 2018: Journal of Biomechanical Engineering
Beth E Lewandowski, Jerry G Myers
A probabilistic model predicts hip fracture probability for post-flight male astronauts during lateral fall scenarios from various heights. A biomechanical representation of the hip provides impact load. Correlations relate spaceflight bone mineral density (BMD) loss and post-flight BMD recovery to bone strength. Translations convert fracture risk index, the ratio of applied load to bone strength, to fracture probability. Parameter distributions capture uncertainty and Monte Carlo simulations provide probability outcomes...
August 16, 2018: Journal of Biomechanical Engineering
Peter Raffalt, Tine Alkjaer, Bjarki Brynjólfsson, Louise J Rgensen, Cecilie R Bartholdy, Marius Henriksen
The present study investigated the day-to-day reliability (quantified by the absolute and relative reliability) of nonlinear methods that assess human locomotion dynamics. Twenty-four participants completed 5 minutes of treadmill walking at self-selected preferred speed on two separate days. Lower limb kinematics were recorded at 100Hz and hip, knee and ankle joint angles, three dimensional sacrum marker displacement and stride time intervals were extracted for 170 consecutive strides. The largest Lyapunov exponent and correlation dimension were calculated for the joint angle and sacrum displacement data using three different state space reconstruction methods (group average, test-retest average, individual time delay and embedding dimension)...
August 4, 2018: Journal of Biomechanical Engineering
Xiaoyan Zhang, Zhan-Qiu Liu, Dara Singh, David K Powell, Charles S Chung, Kenneth S Campbell, Jonathan F Wenk
The present study assessed the acute effects of isoproterenol on left ventricular (LV) mechanics in healthy rats with the hypothesis that ß-adrenergic stimulation influences the mechanics of different myocardial regions of the LV wall in different ways. To accomplish this, magnetic resonance images were obtained in the LV of healthy rats with or without isoproterenol infusion. The LV contours were divided into basal, mid-ventricular, and apical regions. Additionally, the mid-ventricular myocardium was divided into three transmural layers with each layer partitioned into four segments (i...
August 4, 2018: Journal of Biomechanical Engineering
Mohammad Hossein Moshaei, Mohammad Tehrani, Alireza Sarvestani
Adhesion of carrier particles to the luminal surface of endothelium under hemodynamic flow conditions is critical for successful vascular drug delivery. Endothelial cells line the inner surface of blood vessels. The effect of mechanical behavior of this compliant surface on the adhesion of blood-borne particles is unknown. In this contribution, we use a phase-plane method, first developed by Hammer and Lauffenburger [Biophysical Journal, 52, 475 (1987)], to analyze the stability of specific adhesion of a spherical particle to a compliant interface layer...
August 3, 2018: Journal of Biomechanical Engineering
Jay C Hou, Steve A Maas, Jeffrey A Weiss, Gerard A Ateshian
With the recent implementation of multiphasic materials in the open-source finite element (FE) software FEBio (, 3D models of cells embedded within the tissue may now be analyzed, accounting for porous solid matrix deformation, transport of interstitial fluid and solutes, membrane potential, and reactions. The cell membrane is a critical component in cell models, which selectively regulates the transport of fluid and solutes in the presence of large concentration and electric potential gradients, while also facilitating the transport of various proteins...
August 3, 2018: Journal of Biomechanical Engineering
Weili Jiang, Qian Xue, Xudong Zheng
A three-dimensional fluid-structure interaction computational model was used to investigate the effect of the longitudinal variation of vocal fold inner layer thickness on voice production. The computational model coupled a finite element method based continuum vocal fold model and a Navier-Stokes equation based incompressible flow model. Four vocal fold models, one with constant layer thickness and the others with different degrees of layer thickness variation in the longitudinal direction, were studied. It was found that the varied thickness resulted in up to 24% stiffness reduction at the middle and up to 47% stiffness increase near the anterior and posterior ends of the vocal fold; however, the average stiffness was not affected...
August 3, 2018: Journal of Biomechanical Engineering
Giovanni Maria Formato, Mauro Lo Rito, Ferdinando Auricchio, Alessandro Frigiola, Michele Conti
Anomalous aortic origin of coronary arteries (AAOCA) is a congenital disease that can lead to cardiac ischemia during intense physical activity. Although AAOCA is responsible for sudden cardiac death (SCD) among young athletes and soldiers, the mechanisms underlying the coronary occlusion during physical effort still have to be clarified. The present study investigates the correlation between geometric features of the anomaly and coronary lumen narrowing under aortic root dilatations. Idealized parametric computer-aided designed (CAD) models of the aortic root with anomalous and normal coronary are created and static finite element (FE) simulations of increasing aortic root expansions are carried out...
July 23, 2018: Journal of Biomechanical Engineering
James P Charles, Chan-Hong Moon, William Anderst
Accurate individualized muscle architecture data is crucial for generating subject-specific musculoskeletal models to investigate movement and dynamic muscle function. Diffusion tensor magnetic resonance (MR) imaging (DTI) has emerged as a promising method of gathering muscle architecture data in vivo, however its accuracy in estimating parameters such as muscle fiber lengths for creating subject-specific musculoskeletal models has not been tested. Here we provide a validation of the method of using anatomical MRI and DTI to gather muscle architecture data in vivo, by directly comparing those data obtained from MR scans of 3 human cadaveric lower limbs to those from dissections...
July 23, 2018: Journal of Biomechanical Engineering
Andrew Badachhape, Ruth Okamoto, Ramona S Durham, Brent D Efron, Samuel J Nadell, Curtis L Johnson, Philip V Bayly
In this study, displacements of brain tissue in six human subjects and one gelatin "phantom" were measured by MR elastography on two MR scanners. Both were Siemens Trio 3T MRI scanners. One Trio scanner was located at the Beckman Institute at University of Illinois in Urbana-Champaign (UIUC; 4 subjects) and the other Trio scanner was at the Center for Clinical Imaging Research at Washington University in St. Louis (WU; 2 subjects and gel phantom). After publication, we discovered that the default motion-encoding gradient strength was not identical on the two scanners, but was lower on the WU scanner than on the UIUC scanner (20 mT/m vs 26 mT/m on the UIUC scanner)...
July 23, 2018: Journal of Biomechanical Engineering
Henry Y Yu, Christopher Dennison
There is a scant biomechanical literature that tests, in a laboratory setting, whether or not determinants of helmet fit affect biomechanical parameters associated with injury. Using conventional cycling helmets and repeatable models of the human head and neck, integrated into a guided drop impact experiment at speeds up to 6m/s, this study tests the hypothesis that fit affects head kinematics, neck kinetics, and the extent to which the helmet moves relative to the underlying head (an indicator of helmet positional stability)...
July 23, 2018: Journal of Biomechanical Engineering
Magdalena Zuk, Malgorzata Syczewska, Celina Pezowicz
The purpose of the current study was to investigate the robustness of dynamic simulation results in the presence of uncertainties resulting from application of a scaled-generic musculoskeletal model instead of a subject-specific model as well as the effect of the choice of simulation method on the obtained muscle forces. The performed sensitivity analysis consisted of the following multibody parameter modifications: maximum isometric muscle forces, number of muscles, the hip joint centre location, segment masses as well as different dynamic simulation methods, namely static optimization with three different criteria and a computed muscle control algorithm (hybrid approach combining forward and inverse dynamics)...
July 23, 2018: Journal of Biomechanical Engineering
Bernardo Innocenti, Gusztáv Fekete, Silvia Pianigiani
Augments are a common solution for treating bone loss in revision total knee arthroplasty and industry is providing to surgeons several options, in terms of material, thickness and shapes. Actually, while the choice of the shape and the thickness is mainly dictated by the bone defect, no proper guidelines are currently available to select the optimal material for a specific clinical situation. Nevertheless, different materials could induce different bone responses and, later, potentially compromise implant stability and performances...
July 23, 2018: Journal of Biomechanical Engineering
Katia Capellini, Emanuele Vignali, Emiliano Costa, Emanuele Gasparotti, Marco Evangelos Biancolini, Luigi Landini, Vincenzo Positano, Simona Celi
We present a novel framework for the fluid dynamics analysis of healthy subjects and patients affected by ascending thoracic aorta aneurysm (aTAA). Our aim is to obtain indications about the effect of a bulge on the hemodynamic environment at different enlargements. 3D surface models defined from healthy subjects and patients with aTAA, selected for surgical repair, were generated. A representative shape model for both healthy and pathological groups has been identified. A morphing technique based on radial basis functions (RBF) was applied to mould the shape relative to healthy patient into the representative shape of aTAA dataset to enable the parametric simulation of the aTAA formation...
July 23, 2018: Journal of Biomechanical Engineering
Maria Cristina Bisi, Paola Tamburini, Giulia Pacini Panebianco, Rita Stagni
When aiming at assessing motor control development, natural walking (NW) and tandem walking (TW) are two locomotor tasks that allow analysing different characteristics of motor control performance. NW is the reference locomotor task, expected to become more and more automatic with age. TW is a non-paradigmatic task used in clinics to highlight eventual impairments and to evaluate how a child deals with a new challenging motor experience. This work aims at investigating motor development in school-aged children, by assessing quantitatively their performance during TW and NW...
July 20, 2018: Journal of Biomechanical Engineering
John S Wilson, Xiaodong Zhong, Jackson B Hair, W Robert Taylor, John Oshinski
INTRODUCTION: Regional tissue mechanics play a fundamental role in patient-specific cardiovascular function. Nevertheless, regional assessments of aortic kinematics remain lacking due to the challenge of imaging the thin aortic wall. Herein, we present a novel application of DENSE (Displacement Encoding with Stimulated Echoes) MRI to quantify the circumferential Green strain of the thoracic and abdominal aorta. METHODS: 2D spiral cine DENSE and steady-state free procession (SSFP) cine images were acquired at 3T at the infrarenal aorta (IAA), descending thoracic aorta (DTA), or distal aortic arch (DAA) in a pilot study of 6 healthy volunteers...
July 20, 2018: Journal of Biomechanical Engineering
Adam Updegrove, Shawn C Shadden, Nathan Wilson
Image-based modeling is an active and growing area of biomedical research that utilizes medical imaging to create patient-specific simulations of physiological function. Under this paradigm, anatomical structures are segmented from a volumetric image, creating a geometric model that serves as a computational domain for physics-based modeling. A common application is the segmentation of cardiovascular structures to numerically model blood flow or tissue mechanics. The segmentation of medical image data typically results in a discrete boundary representation (surface mesh) of the segmented structure...
July 5, 2018: Journal of Biomechanical Engineering
Nicole Harper, Jason Wilken, Richard Neptune
Ascending stairs is challenging following transtibial amputation due to the loss of the ankle muscles, which are critical to human movement. Efforts to improve stair ascent following amputation are hindered by limited understanding of how prostheses and remaining muscles contribute to stair ascent. This study developed a three-dimensional muscle-actuated forward dynamics simulation of amputee stair ascent to identify contributions of individual muscles and passive prosthesis to the biomechanical subtasks of stair ascent...
July 5, 2018: Journal of Biomechanical Engineering
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