Journal of Biomechanical Engineering This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader or to display this data on your own website or blog.

In Vivo Layer-Specific Mechanical Characterization of Porcine Stomach Tissue Using a Customized Ultrasound Elastography System
This paper presents in vivo mechanical characterization of the muscularis, submucosa, and mucosa of the porcine stomach wall under large deformation loading. This is particularly important for the development of gastrointestinal pathology-specific surgical intervention techniques. The study is based on testing the cardiac and fundic glandular stomach regions using a custom-developed compression ultrasound elastography system. Particular attention has been paid to elucidate the heterogeneity and anisotropy of tissue response. A Fung hyperelastic material model has been used to model the mechanical response of each tissue la...
Source: Journal of Biomechanical Engineering - July 11, 2019 Category: Biomedical Engineering Source Type: research

Dr. Y. C. Fung's Contributions to Biomechanics, Bioengineering, and Humanity: Warmest Celebration for a Magnificent Centenarian
Professor Y. C. Fung has made superb contributions to science, engineering, and humanity through his research and its applications, as well as his words and deeds. By setting the highest standards of rigor and excellence, training many outstanding students and their students, and providing his exemplary leadership, Dr. Fung has made tremendous impacts that spread across the world and transcend time. He established the foundations of biomechanics in a variety of living tissues, including the lung, the heart, blood vessels, blood cells, ureter, intestine, skin, as well as other organs and tissues. Through his vision of the p...
Source: Journal of Biomechanical Engineering - July 10, 2019 Category: Biomedical Engineering Source Type: research

Special Issue: A Tribute to Dr. Y. C. Fung
This September we celebrate the 100th birthday of Professor Y. C. Fung, the Father of Biomechanics. There are multiple events organized in the biomechanics and biomedical engineering communities in honor of Professor Fung, including the YC Fung symposium at the Summer Biomechanics, Bioengineering and Biotransport Conference (SB3C2019) in Seven Spring, PA in June and the YC Fung symposium at San Diego, CA in September. A special issue has been published by theJournal of Medical Biomechanics [1]. The ASMEJournal of Biomechanical Engineering organized this special issue titled “Special Issue: A Tribute to Dr. Y. C Fung,” ...
Source: Journal of Biomechanical Engineering - July 10, 2019 Category: Biomedical Engineering Source Type: research

Three-Dimensional Kinematic Coupling of the Healthy Knee During Treadmill Walking
Accurate joint kinematics plays an important role in estimating joint kinetics in musculoskeletal simulations. Biplanar fluoroscopic (BPF) systems have been introduced to measure skeletal kinematics with six degrees-of-freedom. The purpose of this study was to model knee kinematic coupling using knee kinematics during walking, as measured by the BPF system. Seven healthy individuals (mean age, 23  ± 2 yr) performed treadmill walking trials at 1.2 m/s. Knee kinematics was regressed separately for the swing and stance phases using a generalized mixed effects model. Tibial anterior translation function was y=0.20x−...
Source: Journal of Biomechanical Engineering - May 23, 2019 Category: Biomedical Engineering Source Type: research

Machine Learning-Based Pre-Impact Fall Detection Model to Discriminate Various Types of Fall
In this study, a robust pre-impact fall detection model was developed to classify various activities and falls as multiclass and its performance was compared with the performance of previous developed models. Twelve healthy subjects participated in this study. All subjects were asked to place an inertial measuring unit module by fixing on a belt near the left iliac crest to collect accelerometer data for each activity. Our novel proposed model consists of feature calculation and infinite latent feature selection (ILFS) algorithm, auto labeling of activities, and application of machine learning classifiers for discrete and ...
Source: Journal of Biomechanical Engineering - May 13, 2019 Category: Biomedical Engineering Source Type: research

Thermodynamic Theory and Experimental Validation of a Multiphase Isochoric Freezing Process
Freezing of the aqueous solutions that comprise biological materials, such as isotonic physiological saline, results in the formation of ice crystals and the generation of a hypertonic solution, both of which prove deleterious to biological matter. The field of modern cryopreservation, or preservation of biological matter at subfreezing temperatures, emerged from the 1948 discovery that certain chemical additives such as glycerol, known as cryoprotectants, can protect cells from freeze-related damage by depressing the freezing point of water in solution. This gave rise to a slew of important medical applications, from the ...
Source: Journal of Biomechanical Engineering - May 13, 2019 Category: Biomedical Engineering Source Type: research

Regression Models for the Erector Spinae Muscle Mass (ESMM) Cross-Sectional Area: Asymptomatic Populations
The objective is to perform morphological analyses and then provide regression models to estimate the ESMM CSA of an individual with his/her subject characteristics. Thirty-five subjects (13 females and 22 males) without low back pain (LBP) history were included in this magnetic resonance imaging (MRI) study. Axial-oblique scans of low back region were used to measure the ESMM CSA. Subject demographics and anthropometrics were obtained and regressed over the ESMM CSA. Best-subset regression analyses were performed. Lean body mass (LBM) and the ankle, wrist, and head indexes were the most frequent predictive variables. Regr...
Source: Journal of Biomechanical Engineering - May 13, 2019 Category: Biomedical Engineering Source Type: research

Relative Motion Between the Helmet and the Head in Football Impact Test
Approximately 1.6 –3.8 million sports-related traumatic brain injuries occur each year in the U.S. Researchers track the head motion using a variety of techniques to study the head injury biomechanics. To understand how helmets provide head protection, quantification of the relative motion between the head and the helmet is necessary. The purpose of this study was to compare helmet and head kinematics and quantify the relative motion of helmet with respect to head during experimental representations of on-field American football impact scenarios. Seven helmet-to-helmet impact configurations were simulated by propelling h...
Source: Journal of Biomechanical Engineering - May 6, 2019 Category: Biomedical Engineering Source Type: research

The Phan-Thien and Tanner Model Applied to the Lubrication of Knee Prostheses
This work aims to provide a contribution to determine a proper model for the study of fluid film lubrication for the reduction of knee prostheses failure due to polyethylene wear. The Phan-Thien and Tanner (PTT) rheological law and the elastic deformation of the articular surfaces were considered in this modeling. The governing equations were solved numerically for different geometries and different Weissenberg numbers. The lubrication approximation applied to the PTT rheological law leads to an expression for the apparent viscosity similar to the Cross model. The results attest the importance of considering the non-Newton...
Source: Journal of Biomechanical Engineering - May 6, 2019 Category: Biomedical Engineering Source Type: research

Computational Modeling of Developing Cartilage Using Experimentally Derived Geometries and Compressive Moduli
During chondrogenesis, tissue organization changes dramatically. We previously showed that the compressive moduli of chondrocytes increase concomitantly with extracellular matrix (ECM) stiffness, suggesting cells were remodeling to adapt to the surrounding environment. Due to the difficulty in analyzing the mechanical response of cells in situ, we sought to create an in silico model that would enable us to investigate why cell and ECM stiffness increased in tandem. The goal of this study was to establish a methodology to segment, quantify, and generate mechanical models of developing cartilage to explore how variations in ...
Source: Journal of Biomechanical Engineering - May 6, 2019 Category: Biomedical Engineering Source Type: research

Cholesterol-Dependent Modulation of Stem Cell Biomechanics: Application to Adipogenesis
Cell mechanics has been shown to regulate stem cell differentiation. We have previously reported that altered cell stiffness of mesenchymal stem cells can delay or facilitate biochemically directed differentiation. One of the factors that can affect the cell stiffness is cholesterol. However, the effect of cholesterol on differentiation of human mesenchymal stem cells remains elusive. In this paper, we demonstrate that cholesterol is involved in the modulation of the cell stiffness and subsequent adipogenic differentiation. Rapid cytoskeletal actin reorganization was evident and correlated with the cell's Young's modulus m...
Source: Journal of Biomechanical Engineering - May 6, 2019 Category: Biomedical Engineering Source Type: research

Bridging Finite Element and Machine Learning Modeling: Stress Prediction of Arterial Walls in Atherosclerosis
In this study, we develop a parametric model to generate arterial geometries and accumulate a database of 12,172 2D finite element simulations modeling the hyperelastic behavior and resulting stress distribution. The arterial wall composition mimics vessels in atherosclerosis –a complex cardiovascular disease and one of the leading causes of death globally. We formulate the training data to predict the maximum von Mises stress, which could indicate risk of plaque rupture. Trained deep learning models are able to accurately predict the max von Mises stress within 9.86% error on a held-out test set. The deep neural network...
Source: Journal of Biomechanical Engineering - May 6, 2019 Category: Biomedical Engineering Source Type: research

MMP12 Deletion Preferentially Attenuates Axial Stiffening of Aging Arteries
Arterial stiffening is a hallmark of aging, but how aging affects the arterial response to pressure is still not completely understood, especially with regard to specific matrix metalloproteinases (MMPs). Here, we performed biaxial inflation –extension tests on C57BL/6 mice to study the effects of age and MMP12, a major arterial elastase, on arterial biomechanics. Aging from 2 to 24 months leads to both circumferential and axial stiffening with stretch, and these changes are associated with an increased wall thickness, a decreased i nner radius–wall thickness ratio, and a decreased in vivo axial stretch. Analysis of ...
Source: Journal of Biomechanical Engineering - May 6, 2019 Category: Biomedical Engineering Source Type: research

Effects of Collagenase Type II on Vitreous Humor —An In Situ Rheological Study
We examined thirty-eight porcine eyes using in situ rheological creep tests to measure the mechanical properties of the vitreous humor of the eyes prior to, 1  h and 24 h after the intravitreal injection. Eyes in one group were injected with collagenase type II solution and eyes in the control group were injected with phosphate buffered saline solution (PBS) with calcium and magnesium chloride. Prior to the injection, viscosity and creep compliance in tercept values between both groups were not statistically different. At 1 h and 24 h after the injection, vitreous properties in the eyes from the first group showed ...
Source: Journal of Biomechanical Engineering - May 6, 2019 Category: Biomedical Engineering Source Type: research

Simulated Tremor Propagation in the Upper Limb: From Muscle Activity to Joint Displacement
Although tremor is the most common movement disorder, there are few noninvasive treatment options. Creating effective tremor suppression devices requires a knowledge of where tremor originates mechanically (which muscles) and how it propagates through the limb (to which degrees-of-freedom (DOF)). To simulate tremor propagation, we created a simple model of the upper limb, with tremorogenic activity in the 15 major superficial muscles as inputs and tremulous joint displacement in the seven major DOF as outputs. The model approximated the muscle excitation –contraction dynamics, musculoskeletal geometry, and mechanical imp...
Source: Journal of Biomechanical Engineering - May 6, 2019 Category: Biomedical Engineering Source Type: research