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.

Basin of Attraction and Limit Cycle Oscillation Amplitude of an Ankle-Hip Model of Balance on a Balance Board
In this study, a three degree-of-freedom model for a human balancing on a balance board (BB) was developed. Analysis of the model revealed the BoAs and the amplitude of the LCOs. Results show that physical parameters (time-delays and feedback control gains) have a large impact on the size of the BoA and the amplitude of the LCOs. Particularly, the size of the BoA increases when balancing on a rigid surface and decreases when either proprioceptive or combined visual and vestibular (V&V) feedback gain is too high. With respect to the LCOs, it is shown that they emerge from both the subcritical and supercritical HBs and i...
Source: Journal of Biomechanical Engineering - July 31, 2019 Category: Biomedical Engineering Source Type: research

Rear-Impact Neck Whiplash: Role of Head Inertial Properties and Spine Morphological Variations on Segmental Rotations
This study was designed to investigate the role of variations in spine morphology and head inertia properties on cervical spine segmental rotation in rear-impact whiplash loading. Vertebral morphology is rarely considered as an input parameter in spine finite element (FE) models. A methodology toward considering morphological variations as input parameters and identifying the influential variations is presented in this paper. A cervical spine FE model, with its morphology parametrized using mesh morphing, was used to study the influence of disk height, anteroposterior vertebral depth, and segmental size, as well as variati...
Source: Journal of Biomechanical Engineering - July 31, 2019 Category: Biomedical Engineering Source Type: research

Dynamics of the Tracheal Airway and Its Influences on Respiratory Airflows: An Exemplar Study
Respiration is a dynamic process accompanied by morphological changes in the airways. Although deformation of large airways is expected to exacerbate pulmonary disease symptoms by obstructing airflow during increased minute ventilation, its quantitative effects on airflow characteristics remain unclear. Here, we used in vivo dynamic imaging and examined the effects of tracheal deformation on airflow characteristics under different conditions based on imaging data from a single healthy volunteer. First, we measured tracheal deformation profiles of a healthy lung using magnetic resonance imaging (MRI) during forced exhalatio...
Source: Journal of Biomechanical Engineering - July 31, 2019 Category: Biomedical Engineering Source Type: research

How Stapes Ankylosis and Fracture Affect Middle Ear Dynamics: A Numerical Study
Numerical models of the human middle ear have been developed throughout the last 30  years, for different purposes. While several types of pathologies have been studied, stapedial disorders were seldomly explored. This papers aims to clarify how stapes fracture and some forms of stapes ankylosis, such as stapedial tendon (ST) ossification, augmented pyramidal eminence (PE) and bo ny bar presence, affect the sound transmission through the middle ear. In addition, the stapes dynamics is also analyzed by means of total displacement and first principal strain. For the purpose of the study, first, a three-dimensional finite e...
Source: Journal of Biomechanical Engineering - July 31, 2019 Category: Biomedical Engineering Source Type: research

On the Relative Impact of Intraluminal Thrombus Heterogeneity on Abdominal Aortic Aneurysm Mechanics
Intraluminal thrombus (ILT) is present in the majority of abdominal aortic aneurysms (AAA) of a size warranting consideration for surgical or endovascular intervention. The rupture risk of AAAs is thought to be related to the balance of vessel wall strength and the mechanical stress caused by systemic blood pressure. Previous finite element analyses of AAAs have shown that ILT can reduce and homogenize aneurysm wall stress. These works have largely considered ILT to be homogeneous in mechanical character or have idealized a stiffness distribution through the thrombus thickness. In this work, we use magnetic resonance imagi...
Source: Journal of Biomechanical Engineering - July 31, 2019 Category: Biomedical Engineering Source Type: research

Characterization of Ankle Kinematics and Constraint Following Ligament Rupture in a Cadaveric Model
This study suggests that if patients demonstrate primarily an increased laxity in internal ro tation, the damage has solely occurred to the ATFL; however, if the constraint is reduced across multiple motions, there is likely damage to both ligaments. Higher loads in the Achilles suggest that it is overloaded after the injury; hence, targeting the calf muscles in rehabilitation exercises may reduce patients' pain. (Source: Journal of Biomechanical Engineering)
Source: Journal of Biomechanical Engineering - July 31, 2019 Category: Biomedical Engineering Source Type: research

Personalized Design of Functional Gradient Bone Tissue Engineering Scaffold
The porous structure of the natural bone not only has the characteristics of lightweight and high strength but also is conducive to the growth of cells and tissues due to interconnected pores. In this paper, a novel gradient-controlled parametric modeling technology is presented to design bone tissue engineering (BTE) scaffold. First of all, the method functionalizes the pore distribution in the bone tissue, and reconstructs the pore distribution of the bone tissue in combination with the pathological analysis of the bone defect area of the individual patient. Then, based on the reconstructed pore distribution, the Voronoi...
Source: Journal of Biomechanical Engineering - July 30, 2019 Category: Biomedical Engineering Source Type: research

Inhibition of Contraction Strength and Frequency by Wall Shear Stress in a Single-Lymphangion Model
The phasic contractions of collecting lymphatic vessels are reduced in strength and occur at diminished frequency when a favorable pressure difference and the resulting antegrade flow create large fluid shear stresses at the luminal surface. This paper describes a minimal phenomenological model of this mechanism that is applied to a previously validated numerical model of a phasically contracting lymphangion. The parameters of the inhibition model are quantitatively matched to observations in isolated segments of rat lymphatic vessel, first for mesenteric lymphatics then for thoracic duct, and outcomes from the numerical m...
Source: Journal of Biomechanical Engineering - July 30, 2019 Category: Biomedical Engineering Source Type: research

Two Closely Spaced Aneurysms of the Supraclinoid Internal Carotid Artery: How Does One Influence the Other?
The objective of this study was to use image-based computational fluid dynamics (CFD) techniques to analyze the impact that multiple closely spaced intracranial aneurysm (IAs) of the supra-clinoid segment of the internal carotid artery (ICA) have on each other's hemodynamic characteristics. The vascular geometry of fifteen (15) subjects with 2 IAs was gathered using a 3D digital subtraction angiography clinical system. Two groups of computer models were created for each subject's vascular geometry: both IAs present (model A) and after removal of one IA (model B). Models were separated into two groups based on IA separation...
Source: Journal of Biomechanical Engineering - July 30, 2019 Category: Biomedical Engineering Source Type: research

Human Disc Nucleotomy Alters Annulus Fibrosus Mechanics at Both Reference and Compressed Loads
Nucleotomy is a common surgical procedure and is also performed in ex vivo mechanical testing to model decreased nucleus pulposus (NP) pressurization that occurs with degeneration. Here, we implement novel and noninvasive methods using magnetic resonance imaging (MRI) to study internal 3D annulus fibrosus (AF) deformations after partial nucleotomy and during axial compression by evaluating changes in internal AF deformation at reference loads (50  N) and physiological compressive loads (∼10% strain). One particular advantage of this methodology is that the full 3D disc deformation state, inclusive of both in-plane and ...
Source: Journal of Biomechanical Engineering - July 30, 2019 Category: Biomedical Engineering Source Type: research

A Validated, Specimen-Specific Finite Element Model of the Supraspinatus Tendon Mechanical Environment
This study establishes a rigorously validated specimen-specific (both geometry and material properties) computational model using novel surface strain measurements for the use in investigating the function of the supraspinatus tendon and to ultimately predict the propagation of supraspinatus tendon tears based on the tendon's mechanical environment. (Source: Journal of Biomechanical Engineering)
Source: Journal of Biomechanical Engineering - July 30, 2019 Category: Biomedical Engineering Source Type: research

A Primary Computational Fluid Dynamics Study of Pre- and Post-TEVAR With Intentional Left Subclavian Artery Coverage in a Type B Aortic Dissection
The impact of left subclavian artery (LSA) coverage during thoracic endovascular aortic repair (TEVAR) on the circulatory system is not fully understood. Here, we coupled a single-phase non-Newtonian model with fluid –structure interaction (FSI) technique to simulate blood flow in an acute type B aortic dissection. Three-element Windkessel model was implemented to reproduce physiological pressure waves, where a new workflow was designed to determine model parameters with the absence of measured data. Simulatio ns were carried out in three geometric models to demonstrate the consequence of TEVAR with the LSA coverage; cas...
Source: Journal of Biomechanical Engineering - July 30, 2019 Category: Biomedical Engineering Source Type: research

Fracture Mechanism and Fracture Toughness at the Interface Between Cortical and Cancellous Bone
This study observed that J integral of corticellous bone is higher than the cortical bone since more energy is required for plastic deformation of corticellous bone due to crack branches and slowdown at the interface between cortical and cancellous bone. (Source: Journal of Biomechanical Engineering)
Source: Journal of Biomechanical Engineering - July 30, 2019 Category: Biomedical Engineering Source Type: research

Do Pulmonary Cavity Shapes Influence Lung Function?
Distribution of lung tissue within the chest cavity is a key contributor to delivery of both blood and air to the gas exchange regions of the lung. This distribution is multifactorial with influences from parenchyma, gravity, and level of inflation. We hypothesize that the manner in which lung inflates, for example, the primarily diaphragmatic nature of normal breathing, is an important contributor to regional lung tissue distribution. To investigate this hypothesis, we present an organ-level model of lung tissue mechanics, which incorporates pleural cavity change due to change in lung volume or posture. We quantify the ch...
Source: Journal of Biomechanical Engineering - July 30, 2019 Category: Biomedical Engineering Source Type: research

Assessing the Disturbed Flow and the Transition to Turbulence in the Arteriovenous Fistula
The arteriovenous fistula (AVF) is the main form of vascular access for hemodialysis patients, but its maintenance is very challenging. Its failure is mainly related to intimal hyperplasia (IH), leading to stenosis. The aim of this work was twofold: (i) to perform a computational study for the comparison of the disturbed blood dynamics in different configurations of AVF and (ii) to assess the amount of transition to turbulence developed by the specific geometric configuration of AVF. For this aim, we reconstructed realistic three-dimensional (3D) geometries of two patients with aside-to-end AVF, performing a parametric stu...
Source: Journal of Biomechanical Engineering - July 27, 2019 Category: Biomedical Engineering Source Type: research