bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tangential Stress in Cortical Bone Subjected to Dynamic Axial Loading
Authors: Choi J. H. , Dharan C. K. H. 
Published: November 2021

Abstract
Cortical bone is a complex hierarchical composite lamallae structure consisting, in general, of a mineral phase (calcium hydroxyapatite), an organic phase (collagen) and fluid [1]. In the analysis of bone, the liquid phase is usually neglected, an assumption that is reasonable for steady state or quasi-static loading. However, when cortical bone is loaded dynamically in the axial direction, the presence of the constrained fluid generates time-dependent stresses in the tangential direction. Since the tangential stress acts perpendicular to the weak transverse direction of the bone, it can create damage in this direction. Cyclic axial compressive loading will result in cyclic tensile loading in the tangential direction which can eventually result in fatigue damage. Such damage has actually been observed in studies conducted on heavily exercised race horses where damage was observed in the form of micro cracks oriented perpendicular to the tangential direction and whose fracture planes lie along the axial direction [2].
In this work, cortical bone is modeled as a biphasic material consisting of a permeable composite material filled with fluid. The geometry considered is that of a hollow cylinder made up of multiple concentric permeable lamellae filled with fluid (Fig. 1). When this structure is loaded axially in compression, a tensile tangential stress is developed which decays with time. The decay rate is a function of permeability and radial position. The greater the permeability, the faster the decay rate. The tangential stress peaks at the inner radius and decreases with radial position (Fig. 2). The tangential stress also peaks earlier at the inner radius. The rate of decay is slower at the outside surface where the bone is subjected to the tangential stress for a much longer time than at the inner surface (Fig. 2).
This view of bone as a biphasic structure subjected to dynamic loading may provide a rationale for some of the damage modes observed in vivo in bones subjected to cyclic and impact loading.
Effects of Anterior Spinal Instrumentation on Single-Level Cervical Graft Mechanics
Authors: DiAngelo Denis J. , Liu Weiqiang , Kelly Brian P. , Foley Kevin T. 
Published: November 2021

Abstract
Anterior cervical discectomy with or without graft fusion is an acceptable surgical method for the treatment of cervical spondylosis or other spinal disc diseases. A graft-alone or graft with supplemental spinal instrumentation may be used to immobilize the operated/injured region to promote bony fusion. Graft fusion with instrumentation is intended to restore the mechanical integrity of the operated spine and decrease graft complications. Although the surgical procedure should restore the mechanical integrity of the operated spine, little is known of the load-sharing mechanics of single-level grafted constructs. We have previously shown that anterior instrumentation reverses the loading mechanics of a multi-level cervical strut-graft tested under physiologic flexion and extension conditions (DiAngelo et al., 2000). We hypothesize that a single-level anterior cervical plate will function in a similar manner. That is, a single-level anterior cervical plate will reverse the loads on the graft by loading the graft in extension and unloading the graft in flexion. We also hypothesize that a graft-alone construct does not provide adequate stabilization comparable to that of the graft-plated condition tested in flexion and extension. The objective of the study was to determine the biomechanical stability of four different spine conditions tested under physiologic flexion and extension conditions. They included the harvested, discectomized, graft-alone, and graft with single-level anterior cervical plate.
Finite Element Modelling of a Biocomposite Intervertebral Disc
Authors: Khoang Voon S. , Lim Chwee T. , Ramakrishna Seeram 
Published: November 2021

Abstract
Previous research on artificial intervertebral disc had concentrated on the use of metallic materials like Ti or Co-Cr-Mo alloys for the harder endplates [1], and polymeric materials like Polyurethane for the softer inner core [2,3]. The protocols from these had yielded various degrees of success. In recent years, the use of composite as a biomaterial has attracted much attention due to their highly tailorable material properties. This generates a motivation to use composite materials as a substitute.
In-Vitro Measurements of Microgravity Induced Kinematics Changes on Spine
Authors: Reiter David , Sarigul-Klijn Nesrin , Gupta Munish , Fathallah Fadi 
Published: November 2021

Abstract
It has been observed that astronauts gain height up to 7 cm during space flight due to microgravity effects. This is due partly to the swelling of inter vertabral Dics (IVD). As a result of this most astronauts experiences low back pain. The mechanisms of pain are not well understood yet. The physiological changes that occur from microgravity environment are simulated via bed rest studies on earth. These studies verify the height change and are good simulations of the microgravity of Space Flight. There has not been any studies showing how the fluid shift effects the kinematics of the spine. In our study we designed a ground based in-vitro experiment to measure the kinematics changes induced by microgravity on spine.
Effects of Cortical Shell Concavity on Vertebral Body Compressive Properties
Authors: Liebschner Michael A. K. , Keaveny Tony M. , Rosenberg William S. 
Published: November 2021

Abstract
Quantification of the structural role of the vertebral shell and trabecular centrum is essential to determine if the shell should be given equal consideration when predicting the fracture strength. The contribution of the cortical shell and endplate to the stiffness and strength of the vertebral body is not well understood and the literature remains controversial [1–5]. The uncertainty of the mechanistic support of the cortical shell and the role of its geometry is due in part to the difficulty in obtaining physical information about the shell[5]. A study on sheep vertebrae performed by Kasra and Grynpas [6] suggested a negative correlation between failure load and the tangent of the cortical shell curvature measured in the AP and lateral plane. Nevertheless, the structural role of the vertebral shell may be different in human vertebrae due to altered loading situations and different geometry. Another study by Edmonston et al. [7] implied a strong correlation between vertebral bone density and thoracic curvature. No study reported in the literature investigated the effect of the cortical shell concavity of human vertebral bodies on their mechanical properties.
Development of a Rate-Dependent Material Model for UHMWPE Joint Replacement Components
Authors: Houchaime W. , Petrella A. , Dietz T. , Halloran J. , Rullkoetter P. 
Published: November 2021

Abstract
Polyethylene wear has been implicated in osteolysis and can lead eventually to implant loosening. Abrasive/adhesive wear and delamination or pitting damage in ultra-high molecular weight polyethylene (UHMWPE) joint replacement components has been in part attributed to high joint contact stresses. The propensity of total joint replacement systems for these types of wear is often assessed by evaluating the joint contact stresses and contact areas and these often serve as a basis for differentiation of systems. The rate-dependency of polyethylene can have a significant effect on these contact characteristics of joint replacement components. Previously, researchers have used experimental and analytical methods to determine joint contact characteristics. Most of the analytical studies, however, have not included the important time-dependent behavior of UHWMPE.
Indentation of Articular Cartilage: Effects of Specimen Radius on Determined Properties
Authors: Spoon Corrie E. , Wayne Jennifer S. 
Published: November 2021

Abstract
The indentation test is a commonly used experimental setup to determine properties of articular cartilage, both in the laboratory and as a clinical tool, as it is a test that can be performed in situ. Behavior of normal cartilage and tissue generated in reparative studies have been thus obtained [1, 2, 3]. It has been shown from a finite element study [4] that the behavior of cartilage in indentation stress relaxation can be affected by the tissue width relative to the radius of the indenter. Another finite element study of the indentation of osteochondral defects showed that this ratio also affected specifications of boundary conditions [5]. This investigation sought to evaluate the effect of changing geometric parameters (e.g. tissue width and indenter radius) on the properties determined from creep indentation experiments.
Depth-Dependent Material Property Inhomogeneities Affect the Deformation and Electric Fields in the Chondrocytes and Extracellular Matrix During Compression
Authors: Sun D. D. , Mow V. C. , Lai W. M. , Guo X. E. 
Published: November 2021

Abstract
The biosynthetic activities of chondrocytes are regulated by the mechanical and electrochemical (MEC) environments around cells in the extracellular matrix (ECM) such as matrix deformation, stress/strain, fluid and osmotic pressures and electrical potential [e.g., 1–3]. These MEC parameters are the signals that chondrocytes sense and respond to under mechanical or chemical loading. Therefore, detailed quantification of these MEC signals is a key step toward the understanding the mechano-signal transduction mechanism in cartilage. Since microscopic measurements of MEC environments around cells is generally not possible experimentally, theoretical cell-ECM interaction models have attracted research interests in efforts to predict the MEC fields around and within the chondrocytes encased in the ECM [e.g., 4–6]. These models show that during mechanical compression the responses of the chondrocytes and ECM are intrinsically coupled, influenced by their material properties, and are strongly time and depth dependent [4–6]. For example, the chondrocytes and ECM at the surface zone of the articular cartilage undergo significantly larger axial compression, shear, osmotic pressure and electrical potential than those at the deeper zones [5,6].
Potential Roles for Collagen and Decorin in Strain Rate Sensitive Tendon Fascicle Mechanical Properties
Authors: Robinson Paul S. , Lin Tony W. , Reynolds Paul R. , Derwin Kathleen A. , Iozzo Renato V. , Soslowsky Louis J. 
Published: November 2021

Abstract
Little is known about the contributions of specific extracellular matrix components of tendon to the tissue’s mechanical properties. Type I collagen, given its abundance and association into long fibrils, is thought to dominate the elastic properties of tendon. Proteoglycans (PGs) are believed to provide elasticity through their potential role in transferring stress between discontinuous fibrils, as well as viscoelasticity via their interaction with water. Previous studies suggest relationships between collagen or PGs and tissue mechanics [1,2]. However, no study to date has isolated the contributions that distinct tendon components make to the elastic and viscoelastic properties of tendon. Recently, transgenic mice with prescribed mutations or deletions of various genes for specific tendon constituents have become available. In this study, we use transgenic mice as a tool to investigate the contributions of tendon components to tendon function based on a previously described approach [3]. In particular, we compare the strain rate sensitivity among fascicles from the tails of mice described in Table 1. We hypothesize that (a) fascicles with alterations in type I collagen (C1TJ8 and C1M8) will have different elastic properties but no difference in strain rate sensitivity than age-matched controls (CTL8), and (b) fascicles with alterations in proteoglycan (DKO8 and CTL3 [4]) will have different elastic properties and different strain rate sensitivity than CTL8 fascicles.
Comparison of Two Calcaneal Osteotomies in a Flatfoot Model
Authors: Otis James C. , Sung Il-Hoon , Lee Sam , Hubbard Christopher , Deland Jonathan T. 
Published: November 2021

Abstract
Posterior tibial tendon dysfunction (PTTD) often leads to adult acquired flatfoot deformity. Loss of the tendon’s invertor function results in a progressively lower medial longitudinal arch, hindfoot valgus and forefoot abduction. Treatment varies based on surgeon preference, but typically consists of a medial slide calcaneal osteotomy (slide) and a flexor digitorum longus (FDL) tendon transfer. The concept of a medial displacement calcaneal osteotomy with a posterior distraction (distraction) has been introduced, and demonstrated to significantly reduce the inversion force requirement for heel rise compared to the slide[l]. This finding is significant as it suggests that the distraction is more efficacious than the slide in correcting deformity. However, it has not been validated on a flatfoot model.
Simulation and Control of a Robotic/UFS Testing System With Application to Lumbar Spine Biomechanics
Authors: Doehring Todd C. , Gilbertson Lars G. , Kang James D. 
Published: November 2021

Abstract
Control of biomechanical experiments, especially those involving musculoskeletal joints such as the knee or spine, is a complicated problem because of the highly nonlinear kinematic, structural, and material properties of the tissue. Historically, materials testing machines with one or two degrees of freedom (DOF) (e.g. biaxial Instron, MTS) have been used. However, these devices, originally designed for testing of “standardized” engineering materials, are limited in two critical areas: 1) The number of DOF, and 2) The control system, which restricts the experiment to either “force control” or “displacement control” methods.
Anisotropic Nonlinear Friction at Biomaterial Interfaces: Theory and Application
Authors: Mesfar W. , Shirazi-Adl A. , Dammak M. 
Published: November 2021

Abstract
The interface friction exists in natural and artificial joints as well as many engineering systems in which different bodies articulate. It often plays an important role in mechanics of the system. In the cementless arthroplasty, the friction between the prosthesis (including stems and screws) and the host bone is exploited to increase the stability of the operation. Our previous experimental studies have shown that the interface between bone and various porous coated surfaces exhibit a nonlinear friction that remains nearly the same in different directions; a nonlinear isotropic friction [1,2]. More recent bidirectional friction tests between cancellous bone or polyurethane cubes and a metallic porous coated plate have demonstrated that the interface load-displacement curve is highly nonlinear with significant coupling between two perpendicular directions [3]. Model studies incorporating measured nonlinear response have demonstrated the importance of proper simulation of nonlinear response as compared with Coulomb friction and of the coupling between orthogonal directions [3–5]. In this study, we aim to extend the earlier model studies to incorporate nonlinear direction-dependent anisotropic friction between two surfaces. Our objectives are set to: (a) develop constitutive equations to present interfaces with nonlinear anisotropic friction properties; and (b) implement and apply in a finite element study of a cube resting on a block subjected to normal and shear loads.
A General Adhesive Wear Simulation for Total Joint Replacements: Application to the Patellofemoral Joint
Authors: Petrella Anthony J. , Miller Mark C. 
Published: November 2021

Abstract
Advances in design, materials, and fixation have increased the longevity of total joint replacements and significantly reduced the incidence of mechanical failure or loosening of implant components. Wear of the ultra-high molecular weight polyethylene (UHMWPE) bearing material used in most implants is now among the most important problems in total joint replacement. Wear tests in joint simulators are the gold standard for evaluation of wear resistance and are performed on a routine basis in many research laboratories. Physical wear testing, however, is labor intensive and time consuming. Numerical wear simulations have been developed and applied to the hip joint to evaluate adhesive wear of polyethylene liners [1,2]. The purpose of this project was to develop a general adhesive wear simulation applicable to any articulating joint with arbitrary geometry and subject to arbitrary relative motion. Validation of the model was established through application to the patellofemoral joint of a total knee replacement.
The Wear of UHMWPE in Total Knee Replacements: Experimental and Finite Element Analysis of Contact Behaviour
Authors: Murphy Dorothy M. , Kavanagh Alan , McGloughlin Tim M. 
Published: November 2021

Abstract
Upon examination of failed total knee replacements, it has been concluded that it is the performance of the ultra high molecular weight polyethylene (UHMWPE) tibial component that governs the useful lifespan of such a joint. Severe wear of UHMWPE is associated more with tibial components of the knee than with the acetabular cups of total hip replacements. This is due to a notable lack of congruity between the articulating surfaces which leads to the presence of significant localised stresses in the femoro-tibial interface.
A Direct Comparision of Patient and Simulator Total Knee Replacement Kinematics
Authors: DesJardins John D. , Banks Scott A. , Benson Lisa C. , LaBerge Martine 
Published: November 2021

Abstract
The need to critically evaluate the efficacy of current total knee replacement (TKR) wear testing methodologies is great. Proposed international standards for TKR wear simulation have been drafted, yet their validity continues to be debated. The “gold standard” to which all wear testing methodologies should be compared is the measured in vivo TKR performance of the patient population. With the exception of retrieval analyses, few detailed comparisons of in-vitro vs. in-vivo TKR performance have been performed to date. The current study compares simulator TKR wear testing kinematics to measured in vivo TKR kinematics to evaluate the validity of the proposed ISO force-controlled wear testing methodology.
Comparison of Upper and Lower Hybrid III Dummy Neck Compression Forces Under Vertical Loading
Authors: Friedman Keith 
Published: November 2021

Abstract
The determination of the relationship of the upper and lower Hybrid III dummy neck transducer loads during vertical drop test loading was of interest in the present study. The anthropometric test device is a tool used in crash analysis. It is typically used for frontal or side crash analysis. It has however been used for vertical drop or rollover studies (1).
Simulation of the Central Airways for Identifying Airway Partial Obstruction
Authors: Al-Jumaily A. M. , Du Y. 
Published: November 2021

Abstract
The frequency spectrum of the input impedance determined at the throat is analysed to identify partial occlusion in the branched central bronchi. The airways are modelled starting from the trachea to the second generation and the result demonstrates that the input impedance resonant frequencies can map the location, severity and degree of an obstruction in any of the considered branches.
Numerical Analysis of Blood Flow in a Left Ventricle
Authors: Iwase Hidehito , Liu Hao , Fujimoto Shinichi , Himeno Ryutaro 
Published: November 2021

Abstract
We present a numerical study of dynamical blood flow in a left ventricle of human heart using Computational Fluid Dynamics (CFD). Three-dimensional shape of the left ventricle model was reconstructed using spline interpolation, based on a set of two-dimensional ultrasound echocardiogram images. Blood flow in the left ventricle was computed by solving the incompressible, unsteady Navier-Stokes equations in a manner of Finite Volume Method (FVM). In the present preliminary results the asymmetric intracardiac flow pattern is detected very similar to observed in vivo (Kilner, 2000) which shows a large vortex and a small vortex at diastole.
Modelling and Simulation Methodology for the Human Cardio Vascular System
Authors: Krus Petter , Teien Dag 
Published: November 2021

Abstract
In this paper a methodology for closed loop simulation of the human cardiovascular system is described. It includes a functional heart model and a closed loop circulatory system. Using this model a range of physiological and patophysical phenomena can be studied, such as valvar regurgitation (valve leakage), valvar stenosis, congenital cardiac malformations i.e. coarctation of the aorta and the circulation in univentricular hearts. The model can be extended to accommodate detail descriptions of the subsystems. In this paper, however, a very basic model is shown to highlight the basic principles of cardio vascular system simulation.
The Convexity Properties of the Fung Model for Soft Tissues
Authors: Wilber J. Patrick , Walton Jay R. 
Published: November 2021

Abstract
During the last three decades, the theory of nonlinear elasticity has been used extensively to model biological soft tissues. The now widely accepted belief that an understanding of the mechanical properties of these tissues is critical in order to understand the advent, progression, and treatment of disease has driven this research. More recently, those interested in how soft tissues grow and remodel themselves in response to both normal and pathological conditions have used nonlinear continuum mechanics as a basic tool.
ABAQUS Finite Element Models of Convective Transport in the Walls of Arteries Subjected to Steady and Pulsatile Pressure
Authors: Simon B. R. , Rigby P. H. , Williams S. K. 
Published: November 2021

Abstract
Porohyperelastic (PHE) finite element models (FEMs) have been useful in vascular biomechanics to study the coupled structural response and mobile fluid flux in arterial wall tissues for steady state and cyclic pressures. Previous papers [1,2,3] described PHE FEMs, which determined fluid transport response to representative pulsatile pressures. Those FE analyses have been extended and additional results are given here for cyclic (pulsatile) pressurization of rabbit aortas. The ABAQUS program and a PHE material model were used to simulate fluid transport for “intact” and “de-endothelialized” aortas subjected to “normal” and “hypertensive” pulsatile pressures at heart rates (HRs) of 60 and 120 BPM.
Effect of Position and Flow Waveform on the Fluid Mechanics of a Stenosed Human Right Coronary Artery
Authors: Chandran K. B. , Ramaswamy S. D. , Lai Y.-G. , Wahle A. , Sonka M. 
Published: November 2021

Abstract
Complete occlusion in any of the coronary vessels leads to a myocardial infarction. The role of fluid mechanical forces in atheroma development has been widely accepted because of preferential plaque growth at certain locations of the vessel geometry, such as a bifurcation or regions of high degrees of curvature. Areas of low and/or oscillatory shear stress have been correlated with atheroma development [1]. In order to determine the relationship between fluid mechanical stresses and development of lesions in the coronary vessels, it is important to analyze the fluid mechanics in actual three-dimensional geometries, incorporating the time-dependent translation and geometric alterations of these vessels [2,3].