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Journal of Biomechanical Engineering

Ashkan Javadzadegan, Abouzar Moshfegh, David Fulker, Tracie Barber, Yi Qian, Leonard Kritharides, Andy S C Yong
Computational fluid dynamics (CFD) modeling of myocardial bridging (MB) remains challenging due to its dynamic and phasic nature. This study aims to develop a patient-specific CFD model of MB. There were two parts to this study. The first part consisted of developing an in silico model of the left anterior descending (LAD) coronary artery of a patient with MB. In this regard, a moving-boundary CFD algorithm was developed to simulate the patient-specific muscle compression caused by MB. A second simulation was also performed with the bridge artificially removed to determine the hemodynamics in the same vessel in the absence of MB...
September 1, 2018: Journal of Biomechanical Engineering
Keyvan Amini Khoiy, Anup D Pant, Rouzbeh Amini
The tricuspid valve is a one-way valve on the pulmonary side of the heart, which prevents backflow of blood during ventricular contractions. Development of computational models of the tricuspid valve is important both in understanding the normal valvular function and in the development/improvement of surgical procedures and medical devices. A key step in the development of such models is quantification of the mechanical properties of the tricuspid valve leaflets. In this study, after examining previously measured five-loading-protocol biaxial stress-strain response of porcine tricuspid valves, a phenomenological constitutive framework was chosen to represent this response...
September 1, 2018: Journal of Biomechanical Engineering
Amy L Lenz, Katie A Johnson, Bush Tamara Reid
Many people with amputation utilize a prosthetic device to maintain function and ambulation. During the use of the prosthetic device, their residual limbs can develop wounds called pressure ulcers. The formation of these wounds has been linked to deformation and loading conditions of the skin and deeper tissues. Our research objective was to develop a complete profile of displacements on the gel liner at the interface with the socket during walking in transtibial amputees. Displacements for seven regions along the limb were quantified in addition to six calculations of displacement and three rotations relative to the prosthetic socket...
September 1, 2018: Journal of Biomechanical Engineering
Ryan M Sanford, Sean A Crawford, Helen Genis, Matthew G Doyle, Thomas L Forbes, Cristina H Amon
Fenestrated endovascular aneurysm repair (FEVAR) is a minimally invasive method of abdominal aortic aneurysm (AAA) repair utilized in patients with complex vessel anatomies. Stent grafts (SG) used in this process contain fenestrations within the device that need to be aligned with the visceral arteries upon successful SG deployment. Proper alignment is crucial to maintain blood flow to these arteries and avoid surgical complications. During fenestrated SG deployment, rotation of the SG can occur during the unsheathing process...
September 1, 2018: Journal of Biomechanical Engineering
Ahmet Demirtas, Ani Ural
Recent studies demonstrated an association between atypical femoral fracture (AFF) and long-term bisphosphonate (BP) use for osteoporosis treatment. Due to BP treatment, bone undergoes alterations including increased microcrack density and reduced tissue compositional heterogeneity. However, the effect of these changes on the fracture response of bone is not well understood. As a result, the goal of the current study is to evaluate the individual and combined effects of microcracks and tissue compositional heterogeneity on fracture resistance of cortical bone using finite element modeling (FEM) of compact tension (CT) specimen tests with varying microcrack density, location, and clustering, and material heterogeneity in three different bone samples...
September 1, 2018: Journal of Biomechanical Engineering
Jacob M Reeves, Nikolas K Knowles, George S Athwal, James A Johnson
Quantitative computed tomography (qCT) relies on calibrated bone mineral density data. If a calibration phantom is absent from the CT scan, post hoc calibration becomes necessary. Scanning a calibration phantom after-the-fact and applying that calibration to uncalibrated scans has been used previously. Alternatively, the estimated density is known to vary with CT settings, suggesting that it may be possible to predict the calibration terms using CT settings. This study compares a novel CT setting regression method for post hoc calibration to standard and post hoc phantom-only calibrations...
September 1, 2018: Journal of Biomechanical Engineering
Tony Chen, Moira M McCarthy, Hongqiang Guo, Russell Warren, Suzanne A Maher
The optimal method to integrate scaffolds with articular cartilage has not yet been identified, in part because of our lack of understanding about the mechanobiological conditions at the interface. Our objective was to quantify the effect of mechanical loading on integration between a scaffold and articular cartilage. We hypothesized that increased number of loading cycles would have a detrimental effect on interface integrity. The following models were developed: (i) an in vitro scaffold-cartilage explant system in which compressive sinusoidal loading cycles were applied for 14 days at 1 Hz, 5 days per week, for either 900, 1800, 3600, or 7200 cycles per day and (ii) an in silico inhomogeneous, biphasic finite element model (bFEM) of the scaffold-cartilage construct that was used to characterize interface micromotion, stress, and fluid flow under the prescribed loading conditions...
September 1, 2018: Journal of Biomechanical Engineering
Megan L Bland, Craig McNally, Steven Rowson
Cycling is a leading cause of sport-related head injuries in the U.S. Although bicycle helmets must comply with standards limiting head acceleration in severe impacts, helmets are not evaluated under more common, concussive-level impacts, and limited data are available indicating which helmets offer superior protection. Further, standards evaluate normal impacts, while real-world cyclist head impacts are oblique-involving normal and tangential velocities. The objective of this study was to investigate differences in protective capabilities of ten helmet models under common real-world accident conditions...
September 1, 2018: Journal of Biomechanical Engineering
Raghu N Natarajan, Kei Watanabe, Kazuhiro Hasegawa
Examine the biomechanical effect of material properties, geometric variables, and anchoring arrangements in a segmental pedicle screw with connecting rods spanning the entire lumbar spine using finite element models (FEMs). The objectives of this study are (1) to understand how different variables associated with posterior instrumentation affect the lumbar spine kinematics and stresses in instrumentation, (2) to compare the multidirectional stability of the spinal instrumentation, and (3) to determine how these variables contribute to the rigidity of the long-segment fusion in a lumbar spine...
September 1, 2018: Journal of Biomechanical Engineering
Calvin Kuo, Jake Sganga, Michael Fanton, David B Camarillo
Wearable sensors embedded with inertial measurement units have become commonplace for the measurement of head impact biomechanics, but individual systems often suffer from a lack of measurement fidelity. While some researchers have focused on developing highly accurate, single sensor systems, we have taken a parallel approach in investigating optimal estimation techniques with multiple noisy sensors. In this work, we present a sensor network methodology that utilizes multiple skin patch sensors arranged on the head and combines their data to obtain a more accurate estimate than any individual sensor in the network...
September 1, 2018: Journal of Biomechanical Engineering
Dan T Zaharie, Andrew T M Phillips
The pelvic construct is an important part of the body as it facilitates the transfer of upper body weight to the lower limbs and protects a number of organs and vessels in the lower abdomen. In addition, the importance of the pelvis is highlighted by the high mortality rates associated with pelvic trauma. This study presents a mesoscale structural model of the pelvic construct and the joints and ligaments associated with it. Shell elements were used to model cortical bone, while truss elements were used to model trabecular bone and the ligaments and joints...
September 1, 2018: Journal of Biomechanical Engineering
Cornelis P L Paul, Kaj S Emanuel, Idsart Kingma, Albert J van der Veen, Roderick M Holewijn, Pieter-Paul A Vergroesen, Peter M van de Ven, Margriet G Mullender, Marco N Helder, Theodoor H Smit
Intervertebral disk (IVD) degeneration is commonly described by loss of height and hydration. However, in the first stage of IVD degeneration, this loss has not yet occurred. In the current study, we use an ex vivo degeneration model to analyze the changes in IVDs mechanical behavior in the first phase of degeneration. We characterize these changes by stretched-exponential fitting, and suggest the fitted parameters as markers for early degeneration. Enzymatic degeneration of healthy lumbar caprine IVDs was induced by injecting 100 μL of Chondroïtinase ABC (Cabc) into the nucleus...
September 1, 2018: Journal of Biomechanical Engineering
Rami M A Al-Dirini, Dermot O'Rourke, Daniel Huff, Saulo Martelli, Mark Taylor
Successful designs of total hip replacement (THR) need to be robust to surgical variation in sizing and positioning of the femoral stem. This study presents an automated method for comprehensive evaluation of the potential impact of surgical variability in sizing and positioning on the primary stability of a contemporary cementless femoral stem (Corail®, DePuy Synthes). A patient-specific finite element (FE) model of a femur was generated from computed tomography (CT) images from a female donor. An automated algorithm was developed to span the plausible surgical envelope of implant positions constrained by the inner cortical boundary...
September 1, 2018: Journal of Biomechanical Engineering
P García Carrascal, J García García, J Sierra Pallares, F Castro Ruiz, F J Manuel Martín
In-stent restenosis ails many patients who have undergone stenting. When the stented artery is a bifurcation, the intervention is particularly critical because of the complex stent geometry involved in these structures. Computational fluid dynamics (CFD) has been shown to be an effective approach when modeling blood flow behavior and understanding the mechanisms that underlie in-stent restenosis. However, these CFD models require validation through experimental data in order to be reliable. It is with this purpose in mind that we performed particle image velocimetry (PIV) measurements of velocity fields within flows through a simplified coronary bifurcation...
September 1, 2018: Journal of Biomechanical Engineering
Craig J Goergen, Corey P Neu
No abstract text is available yet for this article.
August 1, 2018: Journal of Biomechanical Engineering
Brandon K Zimmerman, Gerard A Ateshian
This study formulates a finite element algorithm for frictional contact of solid materials, accommodating finite deformation and sliding. The algorithm uses a penalty method regularized with an augmented Lagrangian scheme to enforce contact constraints in a nonmortar surface-to-surface approach. Use of a novel kinematical approach to contact detection and enforcement of frictional constraints allows solution of complex problems previously requiring mortar methods or contact smoothing algorithms. Patch tests are satisfied to a high degree of accuracy with a single-pass penalty method, ensuring formulation errors do not affect the solution...
August 1, 2018: Journal of Biomechanical Engineering
Ferris M Pfeiffer, Suzanne Burgoyne, Heather K Hunt, Johannes Strobel
Innovation arises from creativity. "Thinking outside the box" has long been seen as a necessary precursor to innovation and invention in engineering. However, creativity is rarely part of traditional engineering curricula. In 2015, our group began to explore integrating theater-based creativity methods into bioengineering capstone design. Evaluation of student outcomes was encouraging, so we continued to develop the course in 2016 and 2017. As we worked to refine the pedagogical process, we discovered tensions (real or perceived) between providing academic rigor and allowing students to embrace their creativity; for instance, we experienced some resistance from engineering faculty and students toward adopting methods they viewed as "artsy" or lacking academic rigor...
August 1, 2018: Journal of Biomechanical Engineering
Mohammadreza Khani, Lucas R Sass, Tao Xing, M Keith Sharp, Olivier Balédent, Bryn A Martin
Cerebrospinal fluid (CSF) dynamics are thought to play a vital role in central nervous system (CNS) physiology. The objective of this study was to investigate the impact of spinal cord (SC) nerve roots (NR) on CSF dynamics. A subject-specific computational fluid dynamics (CFD) model of the complete spinal subarachnoid space (SSS) with and without anatomically realistic NR and nonuniform moving dura wall deformation was constructed. This CFD model allowed detailed investigation of the impact of NR on CSF velocities that is not possible in vivo using magnetic resonance imaging (MRI) or other noninvasive imaging methods...
August 1, 2018: Journal of Biomechanical Engineering
(no author information available yet)
No abstract text is available yet for this article.
August 1, 2018: Journal of Biomechanical Engineering
Anita Singh, Dawn Ferry, Susan Mills
This study reports our experience of developing a series of biomedical engineering (BME) courses having active and experiential learning components in an interdisciplinary learning environment. In the first course, BME465: biomechanics, students were immersed in a simulation laboratory setting involving mannequins that are currently used for teaching in the School of Nursing. Each team identified possible technological challenges directly related to the biomechanics of the mannequin and presented an improvement overcoming the challenge...
August 1, 2018: Journal of Biomechanical Engineering
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