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.

Preventing Mesh Pore Collapse by Designing Mesh Pores With Auxetic Geometries: A Comprehensive Evaluation Via Computational Modeling
This study utilized finite element analysis (FEA) to assess the behavior of mesh models with eight auxetic pore geometries subjected to uniaxial loading to evaluate their potential to allow for p ore expansion while simultaneously providing resistance to tensile loading. Overall, substituting auxetic geometries for standard pore geometries yielded more pore expansion, but often at the expense of increased model elongation, with two of the eight auxetics not able to maintain pore expansion at higher levels of tension. Meshes with stable pore geometries that remain open with loading will afford the ingrowth of host tissue in...
Source: Journal of Biomechanical Engineering - March 1, 2018 Category: Biomedical Engineering Source Type: research

Simulating Reversibility of Dense Core Vesicles Capture in En Passant Boutons: Using Mathematical Modeling to Understand the Fate of Dense Core Vesicles in En Passant Boutons
The goal of this paper is to use mathematical modeling to investigate the fate of dense core vesicles (DCVs) captured in en passant boutons located in nerve terminals. One possibility is that all DCVs captured in boutons are destroyed, another possibility is that captured DCVs can escape and reenter the pool of transiting DCVs that move through the boutons, and a third possibility is that some DCVs are destroyed in boutons, while some reenter the transiting pool. We developed a model by applying the conservation of DCVs in various compartments composing the terminal, to predict different scenarios that emerge from the abov...
Source: Journal of Biomechanical Engineering - February 26, 2018 Category: Biomedical Engineering Source Type: research

An Agent-Based Discrete Collagen Fiber Network Model of Dynamic Traction Force-Induced Remodeling
Microstructural properties of extracellular matrix (ECM) promote cell and tissue homeostasis as well as contribute to the formation and progression of disease. In order to understand how microstructural properties influence the mechanical properties and traction force-induced remodeling of ECM, we developed an agent-based model that incorporates repetitively applied traction force within a discrete fiber network. An important difference between our model and similar finite element models is that by implementing more biologically realistic dynamic traction, we can explore a greater range of matrix remodeling. Here, we valid...
Source: Journal of Biomechanical Engineering - February 22, 2018 Category: Biomedical Engineering Source Type: research

Multiscale Poroviscoelastic Compressive Properties of Mouse Supraspinatus Tendons Are Altered in Young and Aged Mice
The objective of this study was to investigate the baseline compressive response of tendon and determine how this response is altered during maturation and aging. We did this by characterizing the compressive mechanical, viscoelastic, and poroelastic properties of young, mature, and aged mouse supraspinatus tendons using macroscale indentation testing and nanoscale high-frequency AFM-based rheology testing. Using these multiscale techniques, we found that aged tendons were stiffer than their mature counterparts and that both young and aged tendons exhibited increased hydraulic permeability and energy dissipation. We hypoth...
Source: Journal of Biomechanical Engineering - February 15, 2018 Category: Biomedical Engineering Source Type: research

A Novel Small-Specimen Planar Biaxial Testing System With Full In-Plane Deformation Control
Simulations of soft tissues require accurate and robust constitutive models, whose form is derived from carefully designed experimental studies. For such investigations of membranes or thin specimens, planar biaxial systems have been used extensively. Yet, all such systems remain limited in their ability to: (1) fully prescribe in-plane deformation gradient tensorF2D, (2) ensure homogeneity of the applied deformation, and (3) be able to accommodate sufficiently small specimens to ensure a reasonable degree of material homogeneity. To address these issues, we have developed a novel planar biaxial testing device that overcom...
Source: Journal of Biomechanical Engineering - February 13, 2018 Category: Biomedical Engineering Source Type: research

Effect of Local Coil Density on Blood Flow Stagnation in Densely Coiled Cerebral Aneurysms: A Computational Study Using a Cartesian Grid Method
Aneurysm recurrence is the most critical concern following coil embolization of a cerebral aneurysm. Adequate packing density (PD) and coil uniformity are believed necessary to achieve sufficient flow stagnation, which decreases the risk of aneurysm recurrence. The effect of coil distribution on the extent of flow stagnation, however, especially in cases of dense packing (high PD), has received less attention. Thus, the cause of aneurysm recurrence despite dense packing is still an open question. The primary aim of this study is to evaluate the effect of local coil density on the extent of blood flow stagnation in densely ...
Source: Journal of Biomechanical Engineering - February 12, 2018 Category: Biomedical Engineering Source Type: research

Mechanical Properties of Arterial Elastin With Water Loss
In this study, a two-stage liquid –vapor method was developed to investigate the effects of water loss on the mechanical properties of porcine aortic elastin. The tissue samples started in a phosphate-buffered saline (PBS) solution at their fully hydrated condition, with a gravimetric water content of 370±36%. The hydration level was reduced by enclosing the tissue in dialysis tubing and submerging it in polyethylene glycol (PEG) solution at concentrations of 10%, 20%, 30%, and 45% w/v, which reduced the water content of the samples to 258±34%, 224±20%, 109±9%, and 58±3%, respectively. The samples were then transfer...
Source: Journal of Biomechanical Engineering - February 12, 2018 Category: Biomedical Engineering Source Type: research

Displacement Propagation in Fibrous Networks Due to Local Contraction
The extracellular matrix provides macroscale structure to tissues and microscale guidance for cell contraction, adhesion, and migration. The matrix is composed of a network of fibers, which each deform by stretching, bending, and buckling. Whereas the mechanics has been well characterized in uniform shear and extension, the response to more general loading conditions remains less clear, because the associated displacement fields cannot be predicted a priori. Studies simulating contraction, such as due to a cell, have observed displacements that propagate over a long range, suggesting mechanisms such as reorientation of fib...
Source: Journal of Biomechanical Engineering - February 12, 2018 Category: Biomedical Engineering Source Type: research

Optimized Time-Resolved Echo Particle Image Velocimetry – Particle Tracking Velocimetry Measurements Elucidate Blood Flow in Patients With Left Ventricular Thrombus
This study introduces optimized procedures that integrate image enhancement, PIV, and particle tracking velocimetry (PTV) to obtain reliable time-resolved two-dimensional (2D) velocity distributions. During initial PIV analysis, multiple results are obtained by varying processing parameters. Optimization involving outlier removal and smoothing is used to select the correct vector. These results are used in a multiparameter PTV procedure. To demonstrate their clinical value, the procedures are implemented to obtain velocity and vorticity distributions over multiple cardiac cycles using images acquired from four left ventric...
Source: Journal of Biomechanical Engineering - February 12, 2018 Category: Biomedical Engineering Source Type: research

A Nonlinear Viscoelastic Model for Adipose Tissue Representing Tissue Response at a Wide Range of Strain Rates and High Strain Levels
In this study, a biofidelic model for adipose tissue is developed for this application. It is a nonlinear viscoelastic model based on the Reese et al.'s formulation. The model is formulated in a large strain framework and applied for finite element (FE) simulation of two types of experiments: rheological experiments and ramped-displacement experiments. The adipose tissue behavior in both experiments is represented well by this model. It indicates the capability of the model to be used in large deformation and wide range of strain rates for application in human body models. (Source: Journal of Biomechanical Engineering)
Source: Journal of Biomechanical Engineering - February 12, 2018 Category: Biomedical Engineering Source Type: research

Evaluation of the Effect of Bariatric Surgery-Induced Weight Loss on Knee Gait and Cartilage Degeneration
The objective of the study was to investigate the effects of bariatric surgery-induced weight loss on knee gait and cartilage degeneration in osteoarthritis (OA) by combining magnetic resonance imaging (MRI), gait analysis, finite element (FE) modeling, and cartilage degeneration algorithm. Gait analyses were performed for obese subjects before and one-year after the bariatric surgery. FE models were created before and after weight loss for those subjects who did not have severe tibio-femoral knee cartilage loss. Knee cartilage degenerations were predicted using an adaptive cartilage degeneration algorithm which is based o...
Source: Journal of Biomechanical Engineering - February 5, 2018 Category: Biomedical Engineering Source Type: research

Does Wrist Laxity Influence Three-Dimensional Carpal Bone Motion?
Previous two-dimensional (2D) studies have shown that there is a spectrum of carpal mechanics that varies between row-type motion and column-type motion as a function of wrist laxity. More recent three-dimensional (3D) studies have suggested instead that carpal bone motion is consistent across individuals. The purpose of this study was to use 3D methods to determine whether carpal kinematics differ between stiffer wrists and wrists with higher laxity. Wrist laxity was quantified using a goniometer in ten subjects by measuring passive wrist flexion –extension (FE) range of motion (ROM). In vivo kinematics of subjects' sca...
Source: Journal of Biomechanical Engineering - February 5, 2018 Category: Biomedical Engineering Source Type: research

Design and Evaluation of an Instrumented Wobble Board for Assessing and Training Dynamic Seated Balance
The objective of this research was to devise and validate a portable tool for assessing and training dynamic seated balance. An instrumented wobble board was designed and constructed that (1) elicits multidirectional perturbations in seated individuals, (2) quantifies seated balance proficiency, and (3) provides real-time, kinematics-based vibrotactile feedback. After performing a technical validation study to compare kinematic wobble board measurements against a gold-standard motion capture system, 15 nondisabled participants performed a dynamic sitting task using the wobble board. Our results demonstrate that the tilt an...
Source: Journal of Biomechanical Engineering - February 2, 2018 Category: Biomedical Engineering Source Type: research

Combining IVUS and Optical Coherence Tomography for More Accurate Coronary Cap Thickness Quantification and Stress/Strain Calculations: A Patient-Specific Three-Dimensional Fluid-Structure Interaction Modeling Approach
Accurate cap thickness and stress/strain quantifications are of fundamental importance for vulnerable plaque research. Virtual histology intravascular ultrasound (VH-IVUS) sets cap thickness to zero when cap is under resolution limit and IVUS does not see it. An innovative modeling approach combining IVUS and optical coherence tomography (OCT) is introduced for cap thickness quantification and more accurate cap stress/strain calculations. In vivo IVUS and OCT coronary plaque data were acquired with informed consent obtained. IVUS and OCT images were merged to form the IVUS  + OCT data set, with biplane angiography prov...
Source: Journal of Biomechanical Engineering - January 23, 2018 Category: Biomedical Engineering Source Type: research

An Outflow Boundary Condition Model for Noninvasive Prediction of Fractional Flow Reserve in Diseased Coronary Arteries
This paper reports on a new boundary condition formulation to model the total coronary myocardial flow and resistance characteristics of the myocardial vascular bed for any specific patient when considered for noninvasive diagnosis of ischemia. The developed boundary condition model gives an implicit representation of the downstream truncated coronary bed. Further, it is based on incorporating patient-specific physiological parameters that can be noninvasively extracted to account for blood flow demand to the myocardium at rest and hyperemic conditions. The model is coupled to a steady three-dimensional (3D) collocated pre...
Source: Journal of Biomechanical Engineering - January 23, 2018 Category: Biomedical Engineering Source Type: research