bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimization of Pole and Slot Widths for Reluctance Torque Reduction in a Brushless DC Spindle Motor
Authors: Chuang T. Y. , Lieu D. K. , McAllister J. S. 
Published: July 2023

Abstract
A parametric study was conducted to determine the effect of motor stator slot widths and rotor permanent magnet pole separation widths on the reluctance torque. This study is based on a finite element analysis of a particular 6-pole/9-slot motor. The analysis can be expanded to other slot/pole combinations. Force and torque calculations were based on an integration of the Maxwell stresses along the center of the airgap. As a general rule, the reluctance torque may be reduced by decreasing the slot width for any given pole separation. For any given slot width, the reluctance torque can be reduced to zero by selection of the proper pole separation. The optimum slot widths are slightly different than those predicted by past analytical formulation. There will be, however, a noticeable effect on the main drive torque and the torque ripple.
Body Height Change From Motor Vehicle Vibration
Authors: Hampel Gary A. , Chang Wen-Ruey 
Published: July 2023

Abstract
Subjects, are exposed to tri-axial whole body vibration for three hours, and measured periodically for height changes. The control was no vibration. A broad band predominantly 2 Hz Z-axis acceleration (mean 0.88ms−2) was input by a truck tractor driven on secondary roads. Effects on subject height from vibration were seen as a tendency for growth in the first hour and to shrink less overall, during the course of the day.
Measurement of Tissue Compressibility Using MR Tagging
Authors: O’Dell W. G. , Moore C. C. , McVeigh E. R. 
Published: July 2023

Abstract
Purpose The evolution of local 3D tissue compressibility in the heart wall may be a sensitive indicator of myocardial perfusion. Characterizing the compressibility of the myocardial tissue in the intact heart is also crucial for the accurate prediction of wall stresses using finite element analysis[1].
Dynamic Flexion Stiffness of Mid-Cervical Intervertebral Joint
Authors: Voo Liming , Pintar Frank A. , Yoganandan Narayan , Liu Y. King 
Published: July 2023

Abstract
Cervical spinal motion segments (two vertebrae and one joint) from fresh human cadavers were tested in sagittal flexion with both quasistatic and high rates of dynamic loading up to 2033 deg/s. The flexion moment was applied by an anterior compressive force through a long lever arm. Each specimen was subjected to three cycles of quasistatic loading and then a single impulsive loading to failure. The resulting moment-angulation characteristics were analyzed to examine their sensitivity to the rate of loading. The experimental dynamic flexion stiffness was found to be 67% higher than the quasistatic stiffness.
Cytoskeleton Rearrangement in Activated Human Neutrophils
Authors: Alteraifi Abdullatif M. , Zhelev Doncho V. 
Published: July 2023

Abstract
The crawling of the neutrophil is essential for its physiological and pathological activity. The neutrophil crawls by projecting pseudopods in the direction of a higher chemoattractant concentration in a process known as chemotaxis. In this process, the cell initially adheres tightly to the present substrate and then rearranges its cytoskeleton. Finally, the ceil body contracts, which results in cell movement. The rearrangement of the cytoskeleton is believed to be a crucial component of cell motility (Cunningham et al., 1992) which determines the overall rate of crawling (Zigmond, 1993). Therefore, it is important to find means of characterizing this in different conditions in order to reveal the role of the different factors in neutrophil motility. The available assays for studying neutrophil motility has one common disadvantage namely, they all produce large contact areas between the cell and the supporting substrate. This large contact area can be coupled with adhesion, which may alter neutrophil activation. To avoid the creation of large contact area with the cell surface in our experiments, we used micropipets. The use of micropipets allow both to minimize the contact area and to manipulate the cellular environment. Using this technique we can produce single pseudopods on individual cells by delivering a known concentration of a chemoattractant to the cell surface. We use the chemoattractant N-formyl-methionyl-leucyl-phenylalanine (fMLP) and by employing the above technique we were able to produce highly oriented cylindrical pseudopods on initially passive neutrophils (Fig. 1). Also, by using another micropipet assay (Zhelev and Hochmuth, 1995) we produced pseudopod-like structures in chemoattractant free solution, by pulling a tether from the cell surface (Fig. 2). In both cases we observe the formation of a dense F-actin network next to the leading edge of the pseudopod or pseudopod-like structure. Also, when the pseudopod or the pseudopod-like structure extends away from the cell body we observe the cell granules penetrating the network region. This penetration shows that there are vacancies in the network region, which indicate network depolymerization. The depolymerization of the network provides conditions for actin turnover (Theriot and Mithchison, 1991).
Concentration of Therapeutic Agents in Neoplasm
Authors: Rooney Frank , Sarntinoranont Malisa , Ferrari Mauro 
Published: July 2023

Abstract
One of the principal objectives of researchers in cancer treatment is to increase the fraction of chemotherapeutic molecules that reaches primary or metastatic malignancies. One possible avenue towards this goal is the coupling of the drug molecule with agents capable of identifying neoplasms, as is typically done with antibody-antigen complexation. While this has had some success, even a perfectly antibody guided therapeutic agent encounters significant complications in reaching the targeted neoplasms. Since these problems are mainly mechanical rather than biological in nature they cannot be dealt with by better biomarker technology. Jain and his coworkers have identified several such obstacles to delivery among them being the blood viscosity and the high interstitial pressures within tumors.
The analysis of Jain et al relates to large tumors and thus may not be appropriate to answer some of the questions of the clinical oncologist. In particular, the assumption that the fluid pressure is time independent limits the scope to large, slowly growing, dominantly necrotic tumors. Though the time scale for convection/diffusion of the macromolecules is very short compared to the typical doubling times for tumors, the assumption of time independence of the fluid pressure is in general not tenable since the pressure varies widely through the growth of the tumor and in particular depends on the tumor growth rate and the absence or presence of a necrotic core. In order to calculate the penetration properties of a chemotherapeutic agent, i.e. the concentration of drug in a tumor, we have used poroelastic constitutive assumptions together with spherical symmetry to obtain a pressure distribution that varies with the tumor’s age. Using this, we can obtain concentration profiles for the early stages of growth of the neoplasm. In fact, we show in Fig. 1 that in the initial growth phase of the tumor the concentration profile rises at first before decreasing with increasing age since the interstitial pressure is not high enough yet to act as a significant barrier to the delivery of the drug.
At present there is a lack of modeling in the area of drug distribution in cancer tumors. Developing better models is important because of their potential as quantitative tools in clinical oncology. Issues such as proper drug dosage, the timing of the insertion and the course of delivery (Fig. 2) are all features of a good model that could guide a practitioner in his work. Our model determines the tumor response as a function of it’s age and also the point at which convection no longer occurs in the majority of the tumor. The model could conceivably be used to determine when this type of therapy is no longer effective, thus saving medical resources and unnecessary chemotherapy side effects for patients.
Oscillatory Flow in a Flexible Curved Tube
Authors: Fujioka Hideki , Oka Kotaro , Tanishita Kazuo 
Published: July 2023

Abstract
The axial dispersion in the High frequency oscillation (HFO) occurs due to the interaction between radial mixing and radially-nonuniform axial velocity profile. The secondary flow works as the lateral mixing in the curved portion of pulmonary bifurcation. Pedley and Kamm (1988) identified the significant effect of curvature on the gas dispersion, and discovered the convective resonance phenomena which gives a highly-peaked local maximum of axial gas transport when the secondary flow circulation time becomes identical to the cycle period. Subsequently Sharp et. al. (1991) experimentally confirmed the presence of convective resonance in a fully developed oscillatory flow in a curved tube. Dragon and Grotberg (1991) presented the effect of wall flexibility on axial mass transport in an oscillatory flow through a infinitely long straight tube. They showed the effective diffusivity, Deff, diminished for all values of α, but Deff attained a local maximum in the HFO range, that coincided with a minimum phase angle between the wall position and the axial flow. Therefore the interaction between the wall and the fluid through a complex airway structure significantly influences the velocity profiles and gas dispersion. In the present study, we performed the numerical simulations of fully developed oscillatory flow through a curved tube with elastic wall in order to investigate the effect of wall flexibility on the secondary flow.
The Advancement of Theoretical Cord Mechanics to Be Used in Tendon and Ligament Research
Authors: Stuckey Jon I. , Conway Ted A. 
Published: July 2023

Abstract
With the ever evolving research in the mechanical identities of live tissues, further development in the area of theoretical cord mechanics is necessary in order to model such structures as tendons and ligaments. The major disadvantage with the current status in cord mechanics is that it is only possible to analyze a helically wound structure, such as a tendon or ligament, if the geometrical attributes of the material are known. This disadvantage can be overcome if a technique can be developed to optimize the geometrical properties of a material by knowing the material properties, the available force in the deflected structure, the design stress for the model, and the bending moment. Geometric optimization will develop by, in essence, deriving the theory of cords in reverse.
Correlation of Wrist Ligamentotaxis With Carpal Distraction During External Fixation
Authors: Loebig Thomas G. , Badia Alejandro , Baratz Mark E. , Anderson Donald D. 
Published: July 2023

Abstract
Distraction of the wrist via external fixation is used to effect and protect the reduction of distal radius fractures by applying tension to the wrist ligaments, a principle known as ligamentotaxis. Wrist and finger stiffness has been associated with overdistraction of the wrist through external fixation (Kaempffe, 1993; Sanders, 1991). A decrease in the range of motion at the metacarpophalangeal (MP) and proximal interphalangeal (PIP) joints has been shown to occur as distraction increases (Moran, 1992). Empirically proposed guidelines for attaining adequate distraction (Agee, 1994; Seitz, 1993) have not been experimentally substantiated. We tested uninjured cadaver wrists to correlate progressive tension across the wrist with associated carpal distraction. To provide a clinically useful method to assess ligamentotaxis, we evaluated the relationships between separation of joint spaces, applied distraction, and the tension carried across the wrist.
Poroelastic Properties of Vertebral Trabecular Bone
Authors: Lim Tae-Hong , Hong Jung Hwa 
Published: July 2023

Abstract
Bone is a composite material consisting of a porous solid phase (mineralized bone tissue) and a fluid phase (blood, marrow, and interstitial fluid). The fluid in bone is known to perform complex functions such as a transport medium biologically as well as the bone remodeling processes. The presence of moving fluid in bone is postulated to contribute to the energy absorbing properties and time-dependent behavior of bone. In numerous studies, the theory of poroelasticity has been used to simulate the bone behavior incorporating the fluid flow in bone. Results of these analytical studies demonstrated the significance of including fluid phase in the studies of bone mechanics. Limitations in these studies, however, are the use of assumed values of poroelastic properties of bone and the lack of experimental validation of their model predictions.
Variationally Derived 3-Field Lagrange Multipler and Augmented Lagrangian Poroelastic Finite Elements for Soft Tissues
Authors: Levenston Marc E. , Frank Eliot H. , Grodzinsky Alan J. 
Published: July 2023

Abstract
Among the approaches to quasistatic poroelastic finite element analyses of soft tissues, the most common versions are 2-field u-w or u-U penalty or “mixed-penalty” formulations (Simon, 1992; Suh et al., 1991; Spilker and de Almeida, 1992) and 2-field u-π or u-p mixed formulations (Simon, 1992; Wayne et al., 1991). The field designations refer to solid (or bulk) displacements u, fluid displacements w or U, and pressures π or p. Although they avoid the numerical ill-conditioning typical of penalty formulations, the u-π and u-p formulations are sub-optimal in that the fluid fields must be derived from the solid and pressure fields. Recently, an infinitesimal strain, constant permeability 3-field mixed u-p-U approach was shown to avoid many of the difficulties of the 2-field penalty and mixed formulations for dynamic soil mechanics applications (Gajo et al., 1994).
Tissue Engineering: The Next Generation of Medical Implants
Authors: Nerem Robert M. 
Published: July 2023

Abstract
The engineering of living tissue, i.e. tissue engineering, involves the use of living cells, manipulated through their extracellular environment or even genetically, to develop biological substitutes for implantation into the body and/or to foster the remodeling of tissue in some other active manner (1). The purpose is to either repair, replace, maintain, or enhance the function of a particular tissue or organ. For some organs, the first step will be extracorporeal devices; however, the long term goal of tissue engineering should be either implantable systems or the in vivo remodeling of tissue. Because there are not enough organs available for transplantation to meet the needs of the individuals on waiting lists, there is a real need for tissue-engineered biological substitutes.
In Vivo Strains in Bone Near Transcortical Implants
Authors: Hiatt Mark J. , Lin Yuan , Powers Dennis L. , Gharpuray Vasanti M. 
Published: July 2023

Abstract
Transcortical implants have been used by numerous investigators to evaluate the response of cortical bone to various implant materials. The experimental model involves drilling holes through the cortex of a long bone of the experimental animal and then placing cylindrical implants or “plugs” of the test material in the drilled holes. The implants are retrieved after a predetermined period of implantation, and the bone/implant interface is assessed either mechanically, using the push-out test, or histologically to determine the response of bone to the material. Conclusions are then drawn as to the suitability of the material for implant applications. However, different researchers have reported a wide range of results from experiments designed to measure the response to apparently similar implant materials (Black, 1989).
Compliant Effect on the Axial Gas Transport in Model Airway
Authors: Inaba Yasuo , Fujioka Hideki , Oka Kotaro , Tanishita Kazuo 
Published: July 2023

Abstract
Many studies on the high-frequency oscillation dealt with the gas transport in a model human airway and pointed out that the axial gas transport is affected by various factors; geometries, tube compliance, the presence of surfactant and others. Particularly Grotberg et al. (1991) theoretically revealed that the role of tube compliance gives a major effect on the axial gas transfer. However, no experimentally reveal the compliant effect on the gas transport in a symmetrical bifurcation, being regarded as a model human airway.
The Stabilty of One-Dimensional Flow in a Finite Collapsible Tube
Authors: Walsh Colin , Fricker Arnaud , Casteret Jerome 
Published: July 2023

Abstract
Flow-induced oscillation of collapsible tubes provides a model for clinical events such as wheezing (Grotberg 1994). Corresponding theories are sought to gain physiological insights. However, such theories use highly simplified analyses. For instance, flutter models of wheezing all assume an infinite length tube (Grotberg and Reiss 1984; Grotberg and Shee 1985; Webster, Sawatzky, Hoffstein, LeBlanc, Hinchey, and Sullivan 1985), and cannot assess the role of inlet and outlet conditions. Below, we give preliminary results dealing with this finite length issue.
In Vitro Evaluation of Combined Cardiac Stenotic and Regurgitant Valve
Authors: Einav S. , Zaretsky U. , Keren G. , Sherez J. 
Published: July 2023

Abstract
The simplified Bernoulli equation may not accurately calculate pressure gradient across the valve in combined aortic stenosis and regurgitation (Cujec, 1992 and Stewart, 1991). The specific aim of this project is to investigate in a pulse duplicator system the pressure and flow changes for a caged and tilting disk aortic valve with combined lesions and to correlate parameters derived from Continuous wave and Color Doppler flow mapping to hemodynamic measurements. The various severity of valve insufficiency and/or stenosis were simulated. Parameters, obtained by Doppler measurements, should be corrected in case of combined aortic valve lesions to avoid incorrect diagnosis. Degree of insufficiency in the stenosed valve influenced pressure gradient. Area of regurgitant jet depends on stenosis severity as well.
Experimental Measurement of Impact Force at Valve Closure of a Tilting Disc Mechanical Heart Valve
Authors: Cheon Gill-Jeong , Lee Jeong-Han , Chandran K. B. 
Published: July 2023

Abstract
Impact forces and strain induced on the guiding struts due to impact between the disc and the struts during the opening and closing phases were measured with a Björk-Shiley monostrut valve in a pulse duplicator simulating physiological pulsatile flow. The maximum impact force imparted on the valve housing during the closing phase of the valve was measured to be 25N for a range of aortic pressures between 13.3 to 21.3 kPa (100 to 160 mm Hg). The maximum value of impact forces on the inlet and outlet struts computed from the force equilibrium were found to be 17N and 9N respectively. However the maximum strain and stress of 2.4 × 10−4 m/m and 47 MPa respectively were measured at the root of the outlet struts, while the strains and stresses at the roots of the inlet strut were negligible. The results of such measurements may be extended for the analysis of the endurance limit and optimal design of the components of a mechanical valve.
The Use of Bioactive Glass Particles As Microcarriers
Authors: Ducheyne Paul , Gao Hongxia , El-Ghannam Ahmed , Shapiro Irving , Ayyaswamy Portonovo 
Published: July 2023

Abstract
Among the various materials that affect bone cell function, and therefore, could serve as the microcarrier material, bioactive glass has been our material of choice. In the early seventies, Hench et al.[1] formulated these glasses with a typical composition of 45% SiO2, 24.5% Na2O, 24.5% CaO and 6% P2O5 (by weight). They documented that upon implantation in bone tissue, this glass called bioactive glass 45S5, firmly adhered to bone. By now, at least nine groups from around the world have shown that glasses typically containing 40–60 mole % SiO2 and various amounts of Na2O, CaO, P2O5 and some smaller amounts of other oxides bond to bone tissue. As the glass is immersed in vivo, bodily fluids cause the glass to corrode. This corrosion results in selective leaching of sodium ions, the formation of a silica gel layer, and eventually the formation of a calcium phosphate rich layer. It is a recent finding that bioactive glass, when made in granular form with a narrow size range (300–355 μm), has the unique capacity to cause differentiation of osteoprogenitor cells to cells expressing the osteoblastic phenotype [2]. This property of upregulating stromal osteoprogenitor cells to osteoblasts in vivo, as well as the capacity to enhance the expression of the osteoblastic phenotype in vitro, form the basis for our selection of bioactive glass 45S5 as the carrier of choice for culturing typical bone tissue cells in microgravity environment.
Development of a Cytoindentation Theory and Experiment for Obtaining Cell Biomechanical Properties
Authors: Shin Daehwan , Athanasiou Kyriacos 
Published: July 2023

Abstract
It is well known that cells respond to mechanical stimuli by altering their biochemical activities. To understand this phenomenon, termed mechanotransduction, it is necessary to quantify cellular stress-strain relationships. Various experiments have been developed in the literature to measure mechanical characteristics of cells. The most widely used technique involves micropipette aspiration to characterize flaccid cells in suspension. The areal modulus of an erythrocyte (Evans and Hochmuth, 1976) and the viscoelastic constants of leukocytes (Schmid-Schönbein et al, 1980) were measured using this technique. More recently “cell poking” was developed (Zahalak et al, 1990) to measure the stiffness and shear modulus of leukocytes. The objectives of our study were to develop a cytoindentation apparatus, experiment, and theoretical model to obtain the intrinsic material properties of the individual cell attached on a substrate.
A Biomechanical Investigation Into the Effects of Overuse Coupled With Intrinsic or Extrinsic Modifications on Rotator Cuff Tendons
Authors: Flanagan Colleen L. , Soslowsky Louis J. , Carpenter James E. , Thomopoulos Stavros , Yian Edward H. 
Published: July 2023

Abstract
One of the most common soft tissue injuries of the musculoskeletal system is injury to the rotator cuff tendons of the shoulder joint. These injuries often limit physical activity (workplace or athletic) and subsequently have a significant impact. Thus, knowledge concerning the etiology and pathogenesis of this condition is important.
Computational Simulations of the Flow Convergence Method for the Quantification of Mitral Regurgitation: Comparison of Fluent and CFD-ACE
Authors: Hopmeyer Joanne , Wilkerson Patrick W. , Levine Robert A. , Yoganathan Ajit P. 
Published: July 2023

Abstract
Mitral regurgitation is a disease of the left side of the heart in which the mitral valve does not close completely during ventricular contraction, causing a jet of blood to be ejected back into the left atrium. The non-invasive quantification of mitral regurgitation is an important but elusive clinical goal and the flow convergence method has shown promise in the assessment of this disease. [1,2]
The Use of Multivariate Johnson Distributions to Model Trunk Muscle Coactivation
Authors: Mirka Gary A. , Glasscock Naomi F. , Stanfield Paul M. , Psihogios Jennie P. 
Published: July 2023

Abstract
A model for predicting trunk muscle coactivation patterns is developed in this research. Electromyographic (EMG) data from ten trunk muscles were collected from 28 subjects as they performed simulated lifting tasks. Nine repetitions of each combination of independent variables were performed by each subject. Included in these exertions were asymmetric postures and dynamic (isokinetic and constant acceleration) exertions. The muscle activity data collected during these trials were used to develop marginal distributions of trunk muscle activity as well as a 10 × 10 correlation matrix that describes how these muscles cooperate in the development of these trunk extension torques. These elements were then combined to generate multivariate distributions describing the coactivation of the trunk musculature.