bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computational Fluid Mechanical Simulation of the Spontaneous Deformation and Alignment of the Endothelial Cell Model Under Fluid Shear Stress
Authors: Yamamoto Yasuhito , Yamaguchi Takami 
Published: July 2023

Abstract
In our previous reports[1–3], using three dimensional computational fluid mechanical models of the endothelial cells under culture condition as well as under the flow condition on the arteriolar wall, we showed that there is strong dependence of the local wall shear stress (WSS) distribution on the cellular shape factors and the alignment. In the present study, a spontaneous random motion of the endothelial cells under culture condition was simulated, and it was shown that the modeled endothelial cells deformed and aligned to the direction to reduce the wall shear stress at the summit of the cells exerted by the flow.
Design of a Rate Controlled Indentor for In Vivo Analysis of Residual Limb Tissues
Authors: Pathak Arvind P. , Silver-Thorn M. Barbara 
Published: July 2023

Abstract
A tissue tester was designed to enable rate controlled indentation of the soft tissues of the residual limbs of below-knee (BK) amputees. Thus viscoelastic phenomena such as pre-conditioning, hysteresis and stress relaxation could be assessed. The tissue tester accommodates indentor excursions of 0–30 mm, performs indentations at rates from 0–5 mm/s, measures reaction forces up to 44 N, and accommodates multiple loading/unloading cycles. The tissue tester is controlled via a notebook personal computer which makes the entire test system portable and amenable for use in a clinical or research environment. The system output consists of force-displacement curves obtained during cyclic loading of the tissue at varying indentation rates at sites of clinical significance to BK prosthetic design. Indentation followed by force monitoring over a fixed time duration allows stress relaxation of the tissue to be assessed. The indentor positioning error (mean error less than 4.4%) is independent of indentor position and load, but dependent on indentation rate. Indentation rates are accurate to within 3% of the desired value and are independent of indentor position and load.
Poroelastic Model of Vertebral Trabecular Bone in the Uniaxial Stress Condition and Experimental Validation
Authors: Hong Jung Hwa , Lim Tae-Hong 
Published: July 2023

Abstract
The theory of poroelasticity that includes the fluid-solid coupled mechanical interactions has been used to study the effect of intraosseous fluid flow on mechanical behavior of trabecular bone. The unique time-dependent behavior and strain rate effect of trabecular bone have been modeled by using the poroelastic theory.1,2 Thus, its general mechanical behavior including the time-dependent and elastic behavior can be predicted using the poroelastic theory. In this study, a 2-D poroelastic model was developed to investigate the effect of strain rate input on mechanical behavior of trabecular bone from the poroelastic constitutive equations under the uniaxial stress condition at various strain rate inputs. Compression tests in the uniaxial stress condition at various strain rates were also performed using bovine vertebral trabecular bone specimens to validate the poroelastic model.
Genetic Strategies for Tissue Engineering
Authors: Morgan Jeffrey R. 
Published: July 2023

Abstract
Recent advances in molecular genetics have resulted in the development of new technologies for the introduction and expression of genes in human somatic cells. These gene transfer technologies have given rise to a potentially new field of medical treatment known as gene therapy. Gene therapy is broadly defined as the transfer of genetic material to cells or tissues in order to achieve a therapeutic effect for inherited as well as acquired diseases. We are exploring the potential application of gene transfer technologies to the field of tissue engineering and are interested in determining if genetic modification can be used to enhance the function and/or performance of cells used as or part of biological substitutes for the restoration, maintenance or improvement of tissue function. We believe that gene transfer technologies will be an important addition to the field of tissue engineering.
Evaluation of 3D Biphasic Finite Element Analysis of Diarthrodial Joint Contact Using Proximity Data
Authors: Dunbar William L. , Spilker Robert L. 
Published: July 2023

Abstract
The mechanical response of cartilage layers in diarthrodial joints to the loads that arise during joint articulation is a problem of contact mechanics. We model cartilage as a biphasic material [1], and use finite element methods to solve the governing differential equations and boundary conditions, including those for contact [2]. Two-dimensional (2D) finite element formulations for biphasic contact have been developed [3], but the complex three-dimensional (3D) contact problem has not yet been solved. We are investigating approximations to the 3D biphasic contact analysis which are computationally feasible and provide insights into the response of physiological tissue layers. The purpose of this study is to evaluate one such method in which the equal-and-opposite applied load distribution on contacting deformable tissue layers is based on the calculated overlap (penetration) between the tissue volumes when they are allowed to rigidly interpenetrate. Our intention is to apply this method to the analysis of diarthrodial joints, where the biphasic tissue layer geometry is obtained using stereophotogrammetry (SPG) [4]. Here we present our approach and evaluate the method using a canonical axisymmetric problem for which an independent biphasic contact solution can be obtained for comparison.
The Effects of Rotator Cuff Tears and the Long Head of the Biceps on Glenohumeral Kinematics
Authors: Wang Vincent M. , Mow Van C. , Raimondo Rick A. , Flatow Evan L. 
Published: July 2023

Abstract
The active restraints of the shoulder, namely the shoulder girdle muscles and tendons, provide the dynamic stability necessary for coordinated and purposeful movement of the upper extremity. Rotator cuff (RC) disease can result in pain, weakness and impaired shoulder function. In studying the pathomechanics of RC tears, an understanding of the biomechanical role of the tendon of the long head of the biceps (LHB) is important, since rupture of the LHB often accompanies RC tears.
A Finite Element Solution of Viscous Flow in Stenotic Elastic Tubes Under an External Pressure and Longitudinal Tension
Authors: Liu Biyue , Tang Dalin 
Published: July 2023

Abstract
Blood flow in collapsible tubes with stenosis has been studied by many authors (Shapiro, 1977; Ku et al, 1990). Tang (1995) introduced an axisymmetric model for viscous flow in stenotic elastic tubes subject to a prescribed traveling external pressure wave and found that the traveling pressure wave has considerable effect on the tube contractions and expansions which are directly related to tube collapsing and re-opening. In this paper, a finite element method is developed to solve a nonlinear mathematical model with free moving boundary to study the viscous flow in stenotic elastic tubes. The model improves Tang’s model (1995) by including the longitudinal tension in the tube law (Pedley, 1992) and revising the boundary conditions to include axial motion of the tube wall.
A Computational Approach for the Evaluation of Left Ventricular Inotropy Based on the Inertial Characterization of the Early Ejection Phase: Comparison With DP/DT
Authors: Redaelli Alberto , Montevecchi Franco Maria 
Published: July 2023

Abstract
This paper presents a computational study, based on a fluid-structure interaction approach. The aim is to investigate the efficacy of the intraventricular pressure drop (dp/dx) and of the first derivative of aortic flow rate (df/dt) as indexes of the left ventricular function by comparison with dp/dt.
Mathematical Modeling and Optimization of the Immobilized Metal Affinity Chromatography
Authors: Patwardhan Anshuman V. , Ataai Mohammad M. , Zenouzi Mansour 
Published: July 2023

Abstract
Immobilized copper affinity chromatography experiments with E. coli cell extract have demonstrated that the cellular proteins of this most commonly used host organism elute from the column in a discontinuous fashion characterized by two major peaks. This result has interesting implications towards the mathematical modeling and subsequent optimization of IMAC. Namely, the elution behavior of the E. coli cell extract can be approximately simulated by simply two representative proteins that have a similar elution behavior as that of the peaks.
We have identified the mixture of Bovine Serum Albumin and Tuna Heart Cytochrome-C to be excellent representatives of the E. coli cell extract. The equilibrium and transport parameters of these proteins were determined experimentally and used in a detailed mathematical model incorporating multicomponent Langmuir isotherm, axial dispersion, film mass transfer and intraparticle diffusion. Target proteins of varying affinities were also included in the model.
Simulation results provided an excellent framework for identifying effective strategies for optimal column utilization as well as for attaining high resolution of the target protein.
Effect of Composition and Damage on Tensile Properties of Chondrocyte Culture Tissue
Authors: Fedewa M. M. , Leo P. , Oegema T. R. , Lewis J. L. 
Published: July 2023

Abstract
Cartilage cracks and fibrillates during the disease osteoarthritis, suggesting material failure as an essential feature of the degradation process. Assumedly, something occurs during the early disease process in the tissue microstructure that makes the material strength lower than normal. The details of this alteration and how the tissue components are organized to carry load is poorly known for cartilage. The purpose of this research was to determine how tissue material properties are related to tissue composition and microstructure and how disease may alter these. Tissue was grown in culture by chondrocytes from young rabbits using several growing media and treatments, and then analyzed for biochemistry and mechanical properties. A theoretical composites material model was used to fit the prefailure data(1).
Mechanical Properties of Chondrocytes and Chondrons
Authors: Guilak Farshid , Ting-Beall H. Ping , Jones Wendy R. , Lee Greta M. , Hochmuth Robert M. 
Published: July 2023

Abstract
The mechanical environment of articular cartilage has a strong modulatory influence on the anabolic and catabolic activities of the chondrocyte. The precise mechanisms by which mechanical loading is transduced to an intracellular signal are not well understood, but are likely to involve the conversion of mechanical factors to other physical phenomena (e.g., osmotic or fluid pressure, electrokinetic effects, etc.). Thus the pericellular matrix, which is the anatomic region immediately surrounding the chondrocyte, may play a dominant role in the mechanical interaction between the chondrocyte and the extracellular matrix [1,2]. Further, the local mechanical environment may also depend on characteristics of the chondrocyte itself, such as cell shape, mechanical properties, and orientation relative to other cells [2]. Previous studies suggest that chondrocytes behave as a viscoelastic solid material [3], although little is currently known regarding the mechanical properties of the pericellular matrix. Recently, techniques have been developed which permit the isolation of viable chondrocytes within their pericellular matrix following enzymatic digestion of the tissue [4]. This entity, composed of single or multiple chondrocytes within a pericellular matrix, has been termed the chondron [1]. The goals of this study were to utilize micropipette aspiration techniques to characterize the mechanical behavior and properties of chondrocytes and of the tissue comprising chondrons (i.e., the pericellular matrix).
Hepatic Tissue Engineering
Authors: Toner Mehmet 
Published: July 2023

Abstract
Each year, approximately 5000 individuals in the United States develop severe enough hepatic failure to require hepatic support. Of these patients, approximately 2000 will undergo orthotopic liver transplantation, currently the only available method for the clinical management of severe hepatic failure. For patients who are not selected for transplantation, there is no adequate treatment available. Those suffering from cirrhosis fight the seventh-leading cause of death in the United States and those suffering from acute liver failure face a mortality of greater than 80%. Although the replacement of liver function using nonbiological, biological, and semibiological or hybrid approaches his been attempted by many investigators, no means for reliable liver replacement, other than organ transplantation, currently exists. One of the most promising approaches for restoring liver function involves the use of cultured hepatocytes that would be part of an extracorporeal device. For a successful extracorporeal device containing stable and functioning hepatocytes, several critical technologies need further development including techniques for (1) long-term hepatocyte culture and methods for reconstructing “in-vivo-like” liver tissue in vitro (2) hepatocyte cryopreservation, and (3) effect of plasma perfusion or in-vivo like fluids on hepatocytes. In this presentation, we will review some of our most recent progress in these three areas. The following is a brief summary.
Towards the Development of a Bioartificial Pancreas: Long-Term In Vitro Functions of Immunoisolated Mouse Insulinoma Cells
Authors: Sambanis Thanassis , Papas Klearchos K. , Long Robert C. , Constantinidis Ioannis 
Published: July 2023

Abstract
A promising method for the long-term treatment of diabetes mellitus consists of the implantation of a functional bioartificial construct containing insulin-secreting cells. Cells are isolated from the immune system of the host by encapsulation in a synthetic semipermeable membrane which allows passage of cellular nutrients and metabolites, including insulin, but excludes antibodies and cytotoxic cells of the host. The effectiveness of such implants in restoring normoglycemia has been repeatedly demonstrated in both small and large diabetic animal models. A limitation to the large-scale application of such implants is cell availability. We are thus investigating the development of stable, functional bioartificial constructs based on transformed insulin-secreting cells that can be amplified in culture thus relaxing the cell availability constrain.
Response of the Spine to Sinusoidal Vertical Vibration
Authors: Kong Wayne Z. , Goel Vijay K. , Wilder David G. , Pope Malcolm H. 
Published: July 2023

Abstract
A finite element model of the upper body was generated to predict the resonant frequency and response to sinusoidal vertical vibration. The model consisted of the lumbosacral spine modeled in detail, and the thorax and cervical spine simulated by beam-type elements. The head and internal organs of the thorax and abdominum were represented by mass elements. The resonant frequencies for vibration in the sagittal plane were extracted. The model was further used to study its response to the vertical vibration imposed at the sacrum and the effects of damping ratio. The first resonant frequency in the vertical direction was predicted as 7.91 Hz. The predicted transfer function was close to the measurements reported in the literature. Both magnitude and phase angle of transmissibility at the resonant frequency increased along the rastral direction. The vertical vibration imposed at the sacrum also caused significant A-P motion and rotation in the sagittal plane in the lumbar vertebrae. The attenuation of the spine to the imposed vibration increased with an increase in damping.
Insights Into the Formation and Characteristics of Leakage Flow Structures Through Bileaflet Mechanical Heart Valve Prostheses
Authors: Ellis Jeffrey T. , Healy Timothy M. , Fontaine Arnold A. , Saxena Rahul , Yoganathan Ajit P. 
Published: July 2023

Abstract
The design of bileaflet prosthetic heart valves deliberately includes some degree of retrograde flow upon valve closure. This reverse flow is intended to “wash out” the hinges of the valve and the areas between leaflet edges and the housing, in principle preventing areas of flow stasis and inhibiting thrombus formation. The speed, direction, and turbulent nature of retrograde flow structures are influenced by the geometry of the hinge which is unique to a given valve design. Typically, the retrograde flow can be classified into two primary events. One is the closure, or “squeeze” flow which occurs because of the onset of an adverse pressure gradient. As the leaflets close in response to this increasing adverse pressure gradient, blood continues to squeeze through the decreasing flow area between the leaflets and in the region between the leaflets and valve housing. Once the valve is closed, the second retrograde flow, the leakage jets, issue from small gaps between the leaflet edges and valve housing, and from the leaflet hinges. Due to the large pressure gradient initially present during valve closure, the leakage jets can be high velocity flows. The closing flow and leakage jets can cause damage to formed blood elements due to high levels of turbulent shear stress. The spatial structure and temporal behavior of these retrograde flow fields have not been previously characterized in great detail. Of particular concern is how these flows may be implicated in blood element damage and how their formation is affected by valve hinge geometry.
Oxygen Mass Transfer in a Stenosis: Effects of Blood-Wall Coupling
Authors: Moore J. A. , Ethier C. Ross , Kaazempur-Mofrad M. 
Published: July 2023

Abstract
Motivation: Arterial transport of blood-borne materials is essential for maintenance of normal arterial wall physiology. Disturbed transport of such materials, due for example to altered hemodynamic patterns caused by local geometric factors, may be linked to the pathogenesis of vascular diseases. A species which is of major interest is oxygen, since it is an important cellular metabolite. Abnormalities in arterial wall oxygen tension have been implicated in the formation of atherosclerotic lesions [5], and may also be linked to intimal hyperplasia [3]. Here we numerically model the transport of oxygen in blood and the arterial wall, taking into account oxygen consumption by cells in the artery wall, coupling of transport between blood and the wall, and the nonlinear oxygen binding properties of hemoglobin.
Analysis of the Stresses and Strains in UHMWPE Components for Total Joint Replacement After Chemical and Mechanical Degradation
Authors: Kurtz Steven M. , Bartel Donald L. , Rimnac Clare M. 
Published: July 2023

Abstract
The purpose of this study was to investigate the combined effects of chemical and mechanical degradation on the stresses in a conforming tibial component. A material model was developed to predict the large-deformation response of degraded UHMWPE as a function of density and cyclic stress. The finite element method was used to determine the stresses due to contact. Forty-five months of simulated degradation was found to increase the stresses associated with surface damage by 12–18%.
Contouring of Spine Implants: A Novel Approach Based on Surgical Navigation Techniques
Authors: Nolte Lutz P. , Liebschner Michael , Bourquin Yvan , Visarius Heiko 
Published: July 2023

Abstract
An often difficult and time-consuming factor inherent to various types of orthopaedic surgery is the contouring of longitudinal fixation devices, e.g. spinal implant rods or fracture fixation plates. These devices need to be bent during surgery to fit geometrical boundary conditions set by the individual anatomy/pathology as well as other components of the implant construct. This may be exemplified by spinal rods to be fit into the pattern set by the pedicle screws inserted as anchors. Inadequate contouring might lead to loosening or failure of associated implant components and/or question surgical outcome. Corrections after improper bending are difficult. Excessive rod bending might significantly alter the implant’s material properties and may cause fatigue failures.
Relation Between the Structural Asymmetry of Coronary Artery Branches and the Angle at Their Origin
Authors: Friedman Morton H. , Ding Zhaohua 
Published: July 2023

Abstract
The relationship between the geometry of branch points on the left anterior descending coronary artery, and the morphometry of the proximal portions of the daughter vessels, was examined. The geometry at 23 branch points on 15 human hearts was derived from multiplane contrast angiograms, and the histology at 28 sites along the daughter vessels was obtained from transverse sections using computerized techniques. The angle of the branch at which the daughter originated was positively correlated with the maximum thicknesses of the intima and media, and with their circumferential asymmetry. The results suggest that large branch angles may favor eccentric intimal thickening, a morphological entity which is thought to be predisposed to lipid accumulation and atherosclerosis.
Biomechanical Analysis of the C1-C2 Transarticular Screw Fixation Technique
Authors: DiAngelo Denis J. , Jansen Thomas H. , Eckstein Eugene C. , Dull Scott T. , Foley Kevin T. 
Published: July 2023

Abstract
Transarticular screw fixation (TASF) is an accepted surgical treatment for pathologic C1-C2 instability due to trauma, ligamentous laxity or degenerative disorders. Previous biomechanical tests have found C1-C2 TASF with a posterior graft to have increased rotational and shear stiffness, as compared with posterior wiring techniques. A complete mechanical analysis of the C1-C2 TASF construct was performed to determine the primary mode of loading. The greatest stress placed on the fixated C1-C2 motion segment was a bending stress developed during flexion and extension.
Influence of Vasoactive Drugs on Wall Shear Stress Distribution in a Compliant Aortic Bifurcation Model
Authors: Lee C. S. , Tarbell John M. 
Published: July 2023

Abstract
The present study compares wall shear rate distributions in a compliant aortic bifurcation model under different hemodynamic states: normal condition, Angiotensin II infusion (vasoconstrictor), and Isoproterenol infusion (vasodilator). The abdominal aortic flow waveforms corresponding to each state were generated in an in vitro flow loop with proper control of wall motion and phase angle between pressure and flow waveforms. The photochromic technique was employed to measure wall shear rates on the moving wall. A low shear stress zone was observed on the outer wall from 5 mm to 15 mm distal to the curvature site. The distribution of wall shear rate was found to be different for the three hemodynamic states simulated in the present study indicating that vasoactive drugs can alter the near wall fluid dynamic environment in the bifurcation.
Stress-Growth Relationships in the Developing Rabbit Distal Femur
Authors: Lerner Amy L. , Kuhn Janet L. , Hollister Scott J. 
Published: July 2023

Abstract
Several pediatric orthopaedic conditions appear to be related to mechanical influences on bone growth. In this study we tested the hypothesis that there is a relationship between bone growth rates and mechanical stresses which are present in the growth plate during normal development. The model selected was the rabbit distal femur, which exhibits a dramatic growth plate curvature resulting from variations in bone growth rates.
A Model of the Artificial Knee for Computer Assisted Functional Planning in Total Knee Replacement
Authors: Martelli Sandra , Marcacci Maurilio , Ellis Randy , Zaffagnini Stefano 
Published: July 2023

Abstract
Long term results of Total Knee Replacement (TKR) are highly dependent on the balance and positioning of the implant. The preoperative planning for a correct TKR positioning is based on the ideal adaptation of shape and kinematics of the prosthesis to the individual features of the patient.