bluuebunny/crossref_metadata_2025_split huggingface dataset:
Clinical Applications of CFD, Visualization and Virtual Reality in Cardiovascular Medicine
Authors: Taylor Charles A. 
Published: January 2022

Abstract
The introduction of computational tools to construct and evaluate models of the anatomy and physiology of human biological systems can enable researchers to test hypotheses regarding abnormal conditions, examine treatments, and, in the long term, enable clinicians to predict the outcome of alternative treatment plans. The computational methods underlying diagnostic imaging are prevalent in clinical environments. However, this diagnostic information, typically expensive to acquire, is provided to the physician without the tools necessary to evaluate the outcome of various treatments. The individual variability and inherent complexity of human biological systems is such that imaging data alone is insufficient to predict the outcome of a given treatment.
Hemodynamic conditions, including velocity, shear, and pressure, play an important role in the modulation of vascular adaptation and the localization of vascular disease. Consequently, understanding the local hemodynamic environment in a region of the vascular system has been an important field of research in the last two decades. In the coming years, computational fluid dynamics methods will move beyond the academic research domain and be implemented in Computer Aided Surgical Planning software. These methods will augment the information available from medical diagnostic imaging to define patient-specific predictive computer models.
Critical issues in the application of CFD, Visualization and Virtual Reality to Cardiovascular Medicine are examined. A software system developed for Computer Aided Surgical Planning which provides an integrated set of tools to test hypotheses regarding the effect of alternate treatment plans on vascular hemodynamics is described.
The Role of Spinal Catheters in Anesthetic Maldistribution
Authors: Myers Matthew R. , Rinaldi Jean E. 
Published: January 2022

Abstract
The ability of small-diameter catheters to uniformly distribute anesthetic within the subarachnoid space of the spinal column was studied, both experimentally and computationally. It was found that there is minimal anesthetic mixing associated with the smallest catheters, both in the free jet emanating from the catheter and the flow interacting with the boundaries of the subarachnoid space. These results may help explain recent occurrences of neurological injuries associated with the use of small-bore catheters for continuous spinal anesthesia.
Comparison Between Calculated Physiologic and Measured Phasic Pressure Gradients Across Human Stenoses Remodeled by Coronary Angioplasty
Authors: Banerjee Rupak K. , Back Lloyd H. 
Published: January 2022

Abstract
The coupling of computational hemodynamics to endovascular diagnostics in human coronary artery stenoses during angioplasty procedures was evaluated. Calculated mean pressure gradients were much lower for physiologic flow than measured mean pressure gradients. The narrower flow cross-section with the catheter present effectively introduced a tighter stenosis than the enlarged residual stenoses after balloon angioplasty; thus elevating the pressure gradient and reducing blood flow during the measurements.
Human Drop Tests of Restrained Occupants in a Small Passenger Car Compartment
Authors: Friedman Keith , Friedman Donald 
Published: January 2022

Abstract
The paper describes experiments involving restrained human volunteer tests in drop tests involving velocities up to 4.2 meters/sec.
The effect of roof crush on restrained occupants has often been discussed without regard to the headroom available, effectiveness of belts, and location of roof crush. In this paper the question of the ability to protect a simply restrained occupant in an environment in which the roof does not crush is addressed.
The results show that, with an effectively designed occupant rollover protection system, restrained occupants of various sizes do not experience serious injurious neck injuries without roof crush.
Dynamic Bending Strength of the Human Forearm
Authors: Pintar Frank A. , Yoganandan Narayan , Voo Liming , Kleinberger Mike 
Published: January 2022

Abstract
The present study was conducted to determine the dynamic bending strength of the human forearm. A total of 30 human cadaver forearm specimens were tested using a three-point bending method to failure at 3.3 to 7.6 m/s speeds. Results indicated significantly (p &lt; 0.01) greater mean failure moment for males (113 ± 39 Nm) compared to females (66 ± 25 Nm). The mean failure bending moment for all specimens was 94 Nm. The smaller sized occupant with lower bone mineral however, has one-half of this strength (approximately 45 Nm). The failure moment of the human forearm was found to be most highly correlated to bone mineral density and forearm weight. The present investigation offers quantitative information regarding strength of the human forearm useful for design of injury-mitigating devices.
Impact Severity During a Fall Is Decreased by Lower Extremity Muscle Contractions During Descent
Authors: Sandler Reuben , Robinovitch Stephen N. 
Published: January 2022

Abstract
Falls are a major cause of injury in the elderly, including the vast majority of hip and wrist fractures, and a considerable portion of vertebral fractures. In the event of a fall, one’s risk for such an injury depends on bone strength, and the configuration and kinetic energy (KE) of the body at the instant it contacts the ground. Consideration of acts such as sitting and squatting suggests that a major determinant of KE is the amount of energy “absorbed” (or negative work performed) during the descent phase of the fall by eccentrically-contracting lower extremity muscles. In the present study, we used a computational model of backwards falling to address the following questions: (1) what degree of impact energy attenuation might be achieved through muscle contraction during the descent phase of falling? and (2) what is the relative importance of muscle contractions at the hip, knee, and ankle in attenuating impact energy?
Development and Validation of a Porohyperelastic Finite Element Model of a Mouse Tail Disc to Investigate Tissue Remodelling
Authors: Duncan Neil A. , Colliou Olivier K. , Lotz Jeffrey C. 
Published: January 2022

Abstract
We developed a porohyperelastic finite element model of the intervertebral disc of a mouse tail. The model prediction of the axial stress-strain response was in good agreement with our experimental results. The stresses in the inner annulus were predicted to be dramatically altered by creep loading. These changes, when compared with our in vivo animal model of disc degeneration in a mouse tail disc, suggested that the biologic changes observed in the inner annulus are consistent with remodelling of the tissue due to an altered stress environment.
Regional Load Sharing in Cervical Spine Intervertebral Disc
Authors: Kumaresan Srirangam , Yoganandan Narayan , Pintar Frank A. , Maiman Dennis J. 
Published: January 2022

Abstract
An anatomically accurate, fully three-dimensional, geometrically and materially nonlinear, and experimentally validated finite element model of the human lower cervical spine was used to study the intervertebral disc biomechanics. The internal axial and shear forces resisted by the ventral, middle and dorsal regions of the intervertebral disc under the axial and eccentric loading modes were quantified. The ventral region resisted higher axial forces with considerable variation from compression-flexion to compression-extension loading. This may explain the higher incidence of osteophytes in this region of the cervical spine. The higher shear forces resisted by the dorsal region of the disc coupled with the presence of bilateral uncovertebral joint anatomy may account for the occurrence of disc herniation in the dorso-lateral region of the spine.
Biomechanical Stability of Multi-Level Inter-Body Cervical Strut-Graft Fusion With Posterior Plating Instrumentation
Authors: DiAngelo Denis J. , Vossel Keith A. , Foley Kevin T. , Rampersaud Y. Raja 
Published: January 2022

Abstract
Strut-graft fusion with supplemental instrumentation is an accepted surgical treatment for multi-level cervical disease. There are many surgical methods for decompressing and reconstructing the cervical spine, e.g., anterior: multi-level discectomy, multi-level interbody strut-graft fusion (SG), multi-level strut-graft with anterior plate instrumentation, or posterior: multi-level laminectomy with posterior lateral mass plating instrumentation. A relatively new surgical approach that combines these methods is multi-level strut-graft fusion with posterior plating instrumentation (SGPP). Although the surgery should restore the mechanical integrity of the operated spine, little is known of the load-sharing mechanics between the SG and posterior instrumentation. Clinically, strut-grafted constructs fail by pistoning of the SG into the adjacent vertebrae, dislodgment of the SG at the vertebral interfaces, SG fracture, hardware breakage, or screw-plate extrusion. The objective of the study was to determine the biomechanical stability of SGPP spinal constructs and to study the influence of posterior plates on strut-graft loading mechanics in vitro.
The Interaction of Muscle Forces With Constraints of Passive Elements in the Knee Joint
Authors: Liu Wen , Maitland Murray 
Published: January 2022

Abstract
A two-dimensional knee model was developed to determine the interaction between muscle forces and passive constraints of the knee joint. The simulated results showed that increased hamstring muscle force reduced anterior shift of the tibia in ACL-deficient knee at the mid-stance of gait. However, it may not be realistic to maintain normal joint position in ACL deficient knee.
Representation of Anisotropy in Constitutive Models of Biological Soft Tissues
Authors: Gardiner John C. , Weiss Jeffrey A. 
Published: January 2022

Abstract
Biological soft tissues are constructed of varying amounts of collagen and elastin fibers embedded in a ground substance matrix holding large amounts of trapped water. This microstructure imparts complicated material behavior to these tissues. Biological soft tissues are anisotropic, nearly incompressible, viscoelastic, nonlinear, inhomogeneous, and undergo large deformations. This combination of properties makes accurate modeling of their behavior a challenge.
Application of a Fiber-Reinforced Continuum Theory to Multiple Deformations of the Annulus Fibrosus
Authors: Klisch Stephen M. , Lotz Jeffrey C. 
Published: January 2022

Abstract
We applied a fiber-reinforced continuum theory to multiple experimental deformations of annulus fibrosus. Both separate and simultaneous regressions were performed while including the traction-free boundary conditions from tensile experiments.
Predicting Biaxial Behavior of the Soft Tissues Using Uniaxial Tensile Tests
Authors: Taban Faruk , Luo Shen-Yi , Evrensel Cahit A. , Mitra Aniruddha 
Published: January 2022

Abstract
The stress-strain curves of the fabric flexible composites and the soft tissues under various biaxial loads appear to be similar. They all contain curved fibers in soft matrices. Because of the curved fibers, inhomogeneous deformation occurs within the material. Most researchers believe that the uniaxial data cannot be used to characterize multiaxial behavior of the soft tissues in general. The constitutive equation obtained using data regression method usually gives a good description of the stress-strain behavior for the homogeneous material. It gives no physical meaning of these input values obtained for the soft tissues. Thus, these constitutive relations are highly dependent on the experimental procedure and cannot be generalized.
Strain Distribution and Relaxation Behaviour of Rat Spinal Cord
Authors: Fiford Rodney J. , Bilston Lynne E. 
Published: January 2022

Abstract
Uniaxial testing of rat spinal cord was performed to investigate the viscoelastic behaviour of spinal cord in tension. Stress relaxation and stress-strain data is presented, and strain distribution within the material is investigated using video analysis and surface markings.
Tensile Properties of Bovine Proximal Tibial Growth Plate Cartilage
Authors: Williams John L. , Do Pat D. , Schmidt Thomas L. 
Published: January 2022

Abstract
Seventy-one microtensile samples of bone-cartilage-bone from the lateral, central and medial portions of the proximal tibial growth plate were tested to failure at three speeds. Tensile strength, toe modulus, tangent modulus, and strain energy density varied by both location and strain rate, being stronger and stiffer on the lateral side and at higher strain rates. No differences could be detected in the ultimate strains by either region or strain rate.
Fracture Toughness of the Femoral Neck, Femoral Shaft, and Tibial Shaft in Aged Bone
Authors: Brown Christopher U. , Yeni Yener N. , Norman Timothy L. 
Published: January 2022

Abstract
This study investigated the relationship between age and the tension and shear fracture toughness of the femoral neck, femoral shaft, and tibial shaft of aged bone greater than 50 years. Fracture toughness for the different bone locations was shown to be different. Cortical bone of the femoral neck had the highest resistance to crack initiation while the femoral shaft had the lowest. Fracture toughness decreased with age for the femoral shaft and the tibia. The ability of cortical bone of the femoral neck to resist fracture, however, did not decline in bone for this age range.
Dynamic Analysis of the Finger Pulley System Using Joint Torque
Authors: Amirouche F. , Koldoff J. , Gonzalez M. 
Published: January 2022

Abstract
The focus of this study was to introduce the use of localized joint torque as a new approach to analyzing finger dynamics. By using a method of continuous acquisition of all the joints in the finger simultaneously and a rigid body model, the principles of inverse dynamics may be applied to calculate the required joint torque for motion. Though this study presents only torque differences, it paves the way for future computations of joint efficiency. Previous investigators have used the Profundus tendon force and excursion to calculate the work of the system (Greenward, 1994). Using the derived equations of motion and kinematic data, the localized work at the joints may be calculated along with accurate measures of bowstringing effects.
Measurement of Stress Distribution in Various Ankle-Foot Orthoses
Authors: Chu Tai-Ming 
Published: January 2022

Abstract
An Ankle-Foot Orthosis (AFO) is a rehabilitation device that supports and aligns the ankle and the foot to improve the functions of the ankle and foot (Wu, 1990). In today’s orthotic industry, polypropylene (PP, a Colyene™ Co-polymer plus Fleshtones and Colors) is used as a major orthotic plastic due to its high weight-strength ratio, high fatigue resistance, light weight, and excellent molding characteristics (1990). However, earlier failure and improper geometry design bring inconvenience in mobility and discomfort to many patients. A literature search shows several investigations have been conducted. A 3-D Finite Element Model (FEM) was developed by Chu, et al. (1995). The analysis includes the computation of the stress level and the determination of locations of stress concentration. Although the 3-D model provided useful information, limited dynamic results were obtained. Yamamoto, et al. (1993) made a comparative study on the mechanical characteristics of plastic AFOs. Eleven AFOs were tested with the motion of dorsiflexion/plantarflexion and inversion/eversion using a muscle-training machine. The objective of this experimental study is to understand the performance of five AFOs used during walking and the resulting deformation developed while under loads. It is intended that the design parameters of AFOs can be evaluated and modified.
The Effect of PCL Substitution on Patellofemoral Joint Forces and A/P Drawer in the Post-TKA Knee
Authors: Petrella Anthony J. , Karmas Alexandros , Berger Richard C. , Rubash Harry E. , Miller Mark C. 
Published: January 2022

Abstract
The decision to retain the posterior cruciate ligament (PCL) in total knee arthroplasty (TKA) is an issue of some debate. The use of a PCL substituting prosthesis relieves the surgeon of the task of properly tensioning the PCL and allows better surgical exposure (Scuderi and Insall, 1989). Moreover, in vitro studies of post-TKA PCL strain (Incavo et al., 1994) as well as clinical studies of TKA function (Worland et al., 1997) have failed to show a significant difference between PCL retaining and substituting knees. In some cases, however, patellofemoral joint (PFJ) complications such as stress fractures have been observed at a higher rate in the PCL substituting knee (Scuderi and Insall, 1989). The objective of this study was to determine the effect of PCL substitution on PFJ forces and anterior-posterior (A/P) drawer. The study proceeded from the hypothesis that no differences between posterior stabilization and cruciate retention would occur.
Optimization of the Design of a Three-Fingered Gripper Capable of Object Manipulation
Authors: Yates Christian A. , Reisinger Kim D. 
Published: January 2022

Abstract
Robotic assist devices typically consist of a manipulator attached to a robot arm. Often, the assist device must perform the functions of the human hand. Therefore, they should have sufficient dexterity to manipulate an object without putting it down. Four fingered manipulators are by their very nature more complex than then three fingered counterparts. But, with the additional finger, the four fingered hands can manipulate an object without setting it down. We describe a novel design that introduces an additional degree of freedom to one finger, and the design optimization process that insures that the six fundamental grasps (spherical, cylindrical, tip, hook, palmar and lateral) are possible. In addition, we discuss how this one additional degree of freedom increases the manipulability of a three fingered manipulator so that a limited array of object manipulation is possible.
Vertebral Endplate Morphology Predicted via Wolff’s Law
Authors: Grosland Nicole M. , Goel Vijay K. , Grobler Leon J. 
Published: January 2022

Abstract
The thin cortical shell and endplate that surround the trabecular centrum of the vertebral body have yet to be characterized completely. Moreover the optimal thickness values have yet to be predicted. The present investigation coupled an adaptive remodeling algorithm with the FE method to predict the optimal external configuration. Results suggest that the endplate responds to the applied loading conditions, yielding a thinning of the endplate over the nucleus. The predicted thickness values were in agreement with experimental measurements.
An Apparatus for Studying Wear Damage in UHMWPE: Description and Initial Test Results
Authors: Baldini Todd H. , Wright Timothy M. , Estupiñán Jaime A. , Bartel Donald L. 
Published: January 2022

Abstract
Wear of ultra high molecular weight polyethylene (UHMWPE) in total joint arthroplasties causes release of particulate debris that contributes to long term complications such as osteolysis and implant loosening (Wright and Goodman, 1996). Despite the magnitude of this clinical problem, little is known about wear mechanisms in UHMWPE implant components and the factors that control them. Total knee replacement designs, for example, require non-conforming metallic on UHMWPE joint surfaces to assure appropriate kinematics and function. Finite element analysis (FEA) has shown that contact between such surfaces leads to high surface and subsurface stresses (Bartel, et al., 1986). Dynamic FEA has also that shown that femoral rollback on the tibia results in considerable residual stresses in the polyethylene (Estupiñán, et al., 1996). In an effort to complement our analytical studies of stresses associated with wear damage, we have developed a wear apparatus. Our objective is to independently control factors including geometry of the joint surfaces, contact load, the presence (sliding) or absence (rolling) of surface velocity, and the polyethylene material properties, so as to experimentally examine their effects on the creation of damage similar to that observed on retrieved joint implants.
Flow Description in a Gastroesophageal Reflux Episode
Authors: Chen Y.-T. , Boehm R. F. , Little A. G. 
Published: January 2022

Abstract
A numerical simulation is performed on a model of a theoretical gastroesophageal reflux behavior. The process modeled here assumes that the lower esophageal sphincter relaxes and opens, allowing a reflux episode to be initiated by a driving pressure differential in the stomach. At that point the pressure differential is removed and the contents flow back down to the gastric cavity. A typical response of the reflux phenomena is shown.
Alterations in Endothelial Permeability After Intravascular Intervention
Authors: Chesler Naomi C. , Brewton Nathan , Ku David N. 
Published: January 2022

Abstract
Intravascular interventions such as balloon embolectomy are effective in removing arterial and venous thrombi and emboli but lead to endothelial injury. The clinical sequelae of this injury include intimal hyperplasia and renewed clot formation. Changes in endothelial permeability after intravascular intervention may influence the development of intimal hyperplasia. To assess the extent and type of injury engendered by the Fogarty embolectomy catheter, the permeability of the endothelium after sham embolectomy (catheter withdrawal in the absence of a thrombus or thrombus model) was measured in porcine carotid arteries. The maximum shear force required for catheter withdrawal was also measured. The changes in permeability resulting from a prototype textured balloon catheter (Applied Medical, Laguna Hills, CA) were measured for comparison to the Fogarty catheter. While the textured balloon showed a distinct pattern of increased permeability and required significantly more force to withdraw at a set balloon pressure than a Fogarty balloon catheter (p &lt; 0.02), there was no difference in permeability after three balloon inflation and removal cycles. This study demonstrates useful techniques for comparing catheter designs which may be clinically relevant to intimal hyperplasia and rethrombosis after intravascular intervention.
A Simplified Mechanical Model to Predict Motion Restrictions of the Partially Paralyzed Shoulder
Authors: Sarver Joseph J. , Seliktar Rahamim 
Published: January 2022

Abstract
Shoulder motion has been studied by several researchers as a control source for a variety of rehabilitative systems such as functional electrical stimulation for the past 20 years (Mortimer et al., 1973) (Johnson and Peckham, 1990) (Fass et al., 1995). In particular studies involving partial paralysis of the muscles controlling the shoulder (such as with spinal cord injuries at the C5 and C4 level) have produced kinematic results which suggest that elevation and retraction of the shoulder are coupled. With an appropriate model of the partially paralyzed shoulder it might be possible to simulate a variety of motions which evaluate currently employed control algorithms. To that end a simplified mechanical model was developed to investigate the feasibility of developing a more complicated model of the partially paralyzed shoulder. The results of the mechanical model predicted that motion of the paralyzed shoulder would indeed be a coupling of elevation and retraction.