bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrodynamic Pressurization of a Trapped Lubricant Pool Between a Rippled Rigid Indenter and an Elastic Layer: An Investigation Into the Role of Surface Roughness on Cartilage Lubrication
Authors: Basalo Ines M. , Ateshian Gerard A. 
Published: November 2021

Abstract
In recent studies of articular diarthrodial joint lubrication, it has been proposed that hydrostatic pressurization of the cartilage interstitial fluid upon joint loading contributes significantly to the load support across the articular layers, thus reducing frictional forces and wear [1–3]. This boundary contact mechanism for porous media can explain the observed time-dependent response of the frictional coefficient. Nevertheless, alternative hypotheses have been also proposed which attribute the low friction coefficient to hydrodynamic lubrication [4]. In our recent analysis of a mixed lubrication problem where a lubricant pool is trapped between a rippled rigid indenter and a biphasic cartilage layer [5], it was observed that the hydrostatic pressurization of the trapped lubricant can enhance the fluid load support to a certain extent, but typically for a short duration on the order of 1 s only, until the lubricant is depleted by flowing into the cartilage layer. Furthermore, under steady-state sliding, it was found that a lubricant pool could not be sustained due to lubricant depletion. These analyses employed an inviscid model for the lubricant as they focused on hydrostatic pressurization only. In the current study, we investigate whether lubricant viscosity, which can promote hydrodynamic pressurization, might further enhance the fluid load support mechanism or alter the conclusions gathered from our earlier studies. To investigate these fundamental mechanisms, an elastic layer is used instead of a biphasic layer at first; a more elaborate biphasic analysis could be employed subsequently if warranted by the current findings.
A Real-Time Approach to Modeling Soft Tissue Deformation
Authors: Mayrose James , Chugh Kevin , Kesavadas T. 
Published: November 2021

Abstract
We are working toward developing a physically accurate real-time abdominal palpation simulator. To achieve this, two major goals must be met. The first is to develop a model that accurately simulates the physical characteristics of the tissues in the human abdomen. The model must not only be physically accurate, it must run in real-time for the simulation to be usable. The second major goal is to design a framework within which to parameterize physical properties of different tissues as well as a methodology to extract those parameters non-invasively.
A Device for Driving a Wire or a Drill Precisely in a Given Direction Through a Point Under Closed Sky Conditions
Authors: Danieli Guido A. , Fragomeni G. , Giuzio E. 
Published: November 2021

Abstract
The paper presents a new device which allows the precise positioning of a guide through a point and in a given direction, or which can permit to reach a given bone section. Other devices exist mainly addressed to the insertion of a screw in the correct position on endo-medullary nails, but these are usually based on the knowledge of the geometry of the nail, and are therefore made by the maker of the nail. In other instances, often the doctors use trial drilling under fluoroscopy to place a kirshner wire in the required position. The actual device is instead based only on an aiming methodology resting on geometrical considerations. Previous knowledge of the position of such a point and direction, which can be given by a hole belonging to a plate or to an endo-medullary nail or can be part of the patient’s bone structure, is not necessary. This is due to the use of fluoroscopy coupled to the localisation of two aiming planes on whose interception is placed the line of interest. A first instrument developed on this principle found limited clinical success due to the complexity of the first kinematic chain used in the aiming process and to human error. A new version has been designed and is at present under construction, which solves the kinematic problem through a careful choice of a series of constraints enabling the aiming process to be divided in sub processes, thus gradually controlling the final result.
Repeatability of a Computer-Aided Optical Tracking System for Total Knee Replacement Surgery
Authors: Sarin Vineet K. , Pratt William R. , Stulberg S. David 
Published: November 2021

Abstract
The success of total knee replacement surgery depends critically on the restoration of limb alignment and on proper implant positioning [1]. Even with contemporary mechanical alignment instrumentation, errors in alignment correction and implant positioning do occur [2–5]. To improve upon the accuracy of conventional mechanical instrumentation, computer-aided navigation systems have been developed for total knee replacement surgery. Clinical studies have demonstrated that use of these systems for knee replacement surgery can lead to improved limb alignment and implant positioning [6–9]. While such systems have been shown to be clinically effective, their overall accuracy and repeatability in clinical use appears to be highly technique dependent [10]. The inherent repeatability (precision) of such systems has not been closely investigated.
Design and Performance of a Surgical Tool Tracking System for Minimally Invasive Surgery
Authors: Brown Jeffrey D. , Rosen Jacob , Longnion Jeff , Sinanan Mika , Hannaford Blake 
Published: November 2021

Abstract
Minimally invasive surgery (MIS) is a technique introduced in the mid-1980s in which a few small incisions are made to allow for insertion of surgical tools and a camera through gasketed ports. Smaller incisions speed patient recovery times and lessen the chance of infection. They also introduce new interfaces as compared to more traditional open surgical techniques. These interfaces impose motion constraints and forces on the tool(s) and hand(s). These interfaces are not well characterized, yet surgical simulators and surgical robots are being developed without this vital information.
Development of an Input Interface Using Ocular Potential for Handicapped Users of Health Care Supporting Computer
Authors: Mizuno F. , Harada A. , Yamaguchi T. 
Published: November 2021

Abstract
Numerous attempts to adapt multimedia communication to medical care have been reported recently. It is our view that spiritual support is more important in medical care, while so-called high technology may be necessary for medical practice. Therefore, we proposed the concept of the Hyper Hospital [1–3], to offer patients a means of effective human communication during medical care. The Hyper Hospital is a medical system constructed on a computer and multimedia based-network, which patients use to participate in medical and care activities through improved communication media. It is sometimes difficult for physically handicapped patients, such as PMD (progressive muscular dystrophy), ALS (amyotrophic lateral sclerosis), and traumatic cervical injury patients, to operate a computer, because of their disabilities. Therefore, there is a serious digital divide between physically disabled patients and healthy people. To remedy this, various communication devices, such as those using winking, eye gaze, voice, and electrical biological signals (event-related potential [4–5], electrooculogram, etc.) have been proposed and tested. These are designed to enable seriously handicapped patients to use a computer without using the usual mechanical input devices, such as a keyboard, mouse, or joystick. Although an EEG (electroencephalogram) offers one source of such potential electrical biological signals, it produces a very weak electrical signal that contaminating noise makes difficult to process. On the other hand, the ocular potential generated by the dipolar potential of the eyeball has a much larger gain in potential than the EEG. Moreover, the ocular potential can be easily controlled by the user, and eye-movement ability remains largely intact, even after neurological diseases progress to a very advanced stage. Therefore, this report studied the development of an input interface for computers using an electrooculogram.
Engineering Analysis of an End-Release Safety Belt Buckle
Authors: Syson Stephen R. 
Published: November 2021

Abstract
A typical end-release safety belt buckle has been analyzed to determine its failure modes. These failure modes were evaluated based on crash test, sled test and component test data. A verification of the hypothesized failure modes was found in the patent literature. The component tests that were conducted confirmed the hypothetical failure modes and verified that the failures could and would occur in real world collisions as well as testing.
Potential Benefits of Adhesive Airway Mucus
Authors: Krumpe Peter , Evrensel Cahit A. 
Published: November 2021

Abstract
What possible benefit could there be to sticky respiratory mucus? Most of the clinical efforts of respiratory therapy are aimed at thinning thick mucus and decreasing its adhesivity to the airway walls. Yet evidence has accumulated that thinning airway mucus may contribute to dependent atelectasis and may worsen respiratory failure in ventilated patients. We speculate that mucus adhesivity benefits cough clearance by keeping mucus in central airways where cough velocity can clear it, rather than allowing backsliding of mucus due to gravity that would result in distal plugging. It follows that mucus in central airways would benefit from increased adhesivity while mucus in distal airways would not.
Platelet Activation in Flow Past Mechanical Heart Valves
Authors: Bluestein Danny , Jesty Jolyon , Saltman Adam E. , Krukenkamp Irvin B. , Suresh Krishnamurthy 
Published: November 2021

Abstract
Numerical studies, in vitro, and in vivo measurements were conducted, aimed at quantifying free emboli formation and procoagulant properties of platelets induced by flow past mechanical heart valves (MHV). Pulsatile turbulent flow simulation was conducted past a St. Jude medical MHV in the aortic position, to study the effects of valve implantation technique on the thromboembolic potential of the valve. A misaligned valve with subannualarly sutured pledgets produced accelerating jet flow through the valve orifices and a wider wake of shed vortices. Shear stress histories of platelets along turbulent trajectories exposed the platelets to elevated shear stresses around the leaflets, leading them to entrapment within the shed vortices. In vitro platelet studies were conducted past the MHV mounted in a recirculation flow loop, by measuring the platelets ability to support the activation of acetylated human prothrombin by factor xa, which enables sequestering flow induced effects and quantification of the platelets activity state. The platelet activation state increased monotonically as a function of the recirculation time past the valve, as measured by the thrombin generation rates in the assay. Finally, platelet activity state measurements were conducted in vivo, from a sheep with an implanted MHV, showing marked increase of platelet activation after valve implantation.
An Automated Methdology for Investigating the Correlation Between Abdominal Aortic Aneurysm Wall Stress and Risk of Rupture
Authors: Raghavan Madhavan L. , Fillinger Mark F. , Marra Steven P. , Kennedy Francis E. 
Published: November 2021

Abstract
Clinical experience with regard to predicting abdominal aortic aneurysm (AAA) rupture has shown that although AAA diameter is a good indicator, there are likely other risk factors. Some researchers have explored a biomechanical approach to predicting aneurysm rupture risk [1,2] based on the hypothesis that aneurysm rupture occurs when the mechanical stresses in the aortic wall exceed the wall failure strength. Therefore, knowledge of wall stresses in a particular AAA may help identify impending rupture. Recently, researchers have used patients’ abdominal CT scan data and blood pressure to estimate in-vivo AAA wall stresses [3]. In the present project, an improved automated methodology is used to predict AAA wall stress. The underlying correlation between mechanical stress and aneurysm wall rupture is also investigated.
Effect of Variations in Intraluminal Thrombus Constitutive Properties on Abdominal Aortic Aneurysm Wall Stress: A Parametric Study
Authors: Di Martino Elena S. , Wang David H. J. , Redaelli Alberto , Makaroun Michel S. , Vorp David A. 
Published: November 2021

Abstract
The prevalence of abdominal aortic aneurysm (AAA) is growing together with population age, being 8.8% in a population above 65 years according to a recent study [1]. Deciding between elective surgical repair of AAA and watchful management is a complex issue due to the lack of reliable rupture risk indices. The maximum transverse diameter of AAA is most commonly used in clinical practice to base this decision. From a biomechanical viewpoint, AAA rupture is related to the balance between the stresses acting on the wall and strength of the wall tissue. Many different factors contribute to the stress within the aortic aneurysm wall, including the presence of intraluminal thrombus (ILT) [2–5], the local surface curvature [6] and material characteristics of the AAA wall [7], and the presence of local “stress concentrators” due to calcifications or local thinning. As regards the ILT, its role with respect to aneurysm wall stresses has given rise to many hypotheses. Some studies show that the pressure inside the thrombus is not reduced with respect to the arterial blood pressure, some, including studies from the authors, state a possible protective role [2–5]. Previously in our laboratory, a nonlinear, hyperelastic constitutive model was developed for ILT, and the parameters for which were determined through ex-vivo experimentation [8]. The purpose of this study was to investigate the reliability of using the same population-mean values of ILT constitutive parameters for estimates of wall stress distribution in all AAA. For this, we performed a parametric study in which the ELT constitutive parameters were varied within a physiological range and aortic wall stresses were evaluated.
3-D Simulation for Blood Flow and Artery Compression in Asymmetric Stenotic Arteries With Axial Stretch
Authors: Tang Dalin , Yang Chun , Kobayashi Shunnichi 
Published: November 2021

Abstract
There has been increasing evidence that severe stenosis may cause artery compression and plaque cap rupture leading to heart attack and stroke. The physiological conditions under which that may occur and mechanisms involved are not well understood. It has been known that severe stenosis causes critical flow and wall mechanical conditions such as flow limitation, flow separation, low and oscillating shear stress distal to the stenosis, high shear stress and low or even negative flow pressure at the throat of stenosis, artery compression or even collapse. Those conditions are related to limitation of blood supply, intimal thickening and thrombosis formation, endothelism damage, platelet activation and aggregation, plaque cap rupture (for review, see [1,2]). Due to the complexity of the problem and lack of experimental data for mechanical properties of arteries under both expansion and compression, previous models were limited primarily to flow behaviors and with various limitations (axisymmetry, rigid wall, small strain, small pressure gradient). In this paper, experimental data for artery mechanical properties under physiological conditions were measured and a 3-d computational model is introduced to investigate flow behaviors and wall stress and strain distributions with fluid-structure interactions to better understand the mechanism involved in artery compression and plaque cap rupture.
Designing Intravascular Stent: A Computational Study
Authors: Migliavacca Francesco , Petrini Lorenza , Colombo Maurizio , Auricchio Ferdinando , Pietrabissa Riccardo 
Published: November 2021

Abstract
Intravascular stents are small tube-like structures placed into stenotic arteries to restore blood flow perfusion to the downstream tissues. The first implanted stent was first described by Dotter [1] to treat arterial shrinkage, but the clinical routine implantation began in the 1990s to improve the limitations of balloon angioplasty, such as restenosis and abrupt closure. If compared to angioplasty, stent higher efficiency is supported by randomized trials and clinical studies. Nevertheless, problems and difficulties remain, such as migrations, collapses, cloth formation or positioning difficulties (flexibility, trackability, etc...). In other words, although intravascular stents are nowadays routinely and successfully used, research and development are still necessary, to improve the design and to avoid the long-term failure.
Improved Histologic Analysis of Component Distribution and Wall Behavior in Cyanoacrylate-Embolized Vessels
Authors: Calvo William J. , Lieber Baruch B. , Wakhloo Ajay K. , Hopkins L. Nelson 
Published: November 2021

Abstract
Use of embolic agents is currently an accepted treatment modality among neurointerventional clinicians in order to completely occlude abnormal shunts in the cerebral vasculature known as arteriovenous malformations or AVMs. The first cyanoacrylate polymer recently approved by the US Food and Drug Administration for use in humans is n-butyl 2-cyanoacrylate (NBCA). In order to control the polymerization time of NBCA, as well as to opacify the mixture for angiographic visualization, an iodized poppyseed oil-based contrast agent (Lipiodol) is added to the NBCA. Glacial acetic acid is also used to delay polymerization further by decreasing the pH of the mixture.
Quantification of Diastolic Viscoelastic Properties of Isolated Cardiac Muscle Cells
Authors: Baicu Catalin F. , Zile Michael R. 
Published: November 2021

Abstract
Pathological processes which cause diastolic congestive heart failure (CHF), such as pressure overload hypertrophy (POH), produce abnormalities in the material properties of cardiac muscle cells (cardiomyocytes) and may selectively alter its elastic stiffness, viscosity, or both. Previous methods used to characterize these cardiomyocyte viscoelastic properties were constrained by specific biological and engineering limitations, which prevented testing in conditions that mimic normal physiology. The current study proposes an uniaxial variable-rate stretching method, in which isolated cardiomyocytes embedded in a three-dimensional gel matrix were subjected to stretch. Physiological Ca++ (2.5 mM) and rapid stretch rates up to 100 μm/sec provided experimental conditions parallel to in vivo physiology. The proposed method identified and individually quantified both cellular stiffness and viscosity, and showed that POH increased both elastic and viscous cardiomyocyte diastolic properties.
A Material Model for Shortening-Dependent Stiffness of Tracheal Smooth Muscle
Authors: Sarma P. A. , Pidaparti R. M. , Meiss R. A. 
Published: November 2021

Abstract
The objectives of the present study are to develop a material model of a tracheal smooth muscle tissue from experimental data, and to simulate the mechanical response through a three-dimensional nonlinear finite element analysis. The developed material model and simulation models are validated against the experimental data. The results obtained indicate that the approach and the material model developed are useful for describing the length-dependent characteristics of tracheal smooth muscle tissue.
The Influence of Non-Newtonian Behavior on Mass Transfer in Separated Flows at High-Schmidt Numbers
Authors: Hammad Khaled J. 
Published: November 2021

Abstract
The present study examines the influence of non-Newtonian rheology on dilute species transport from laminar, separating and re-attaching flows to a confining adsorbing boundary under steady conditions. Wall-bounded separating and re-attaching flows are encountered in many biological applications such as those dealing with blood flows through arteries and prosthetic devices. The investigation is carried out in the axisymmetric sudden expansion geometry since it displays flow characteristics similar to those encountered in physiological flows. The fixed separation location and the always present flow reversal region immediately downstream of the expansion plane, even for creeping flows, makes it easier to relate changes in the flow structure to variations in a specific governing parameter. Particular uses of the sudden expansion geometry in modeling physiological flows are very well documented ([1], [2], [3] and [4]).
Modeling of Friction Induced Vibration due to Third-Body Effects
Authors: Xu David S. , Heshmat Hooshang 
Published: November 2021

Abstract
Friction induced vibration at contact interfaces is still a big challenging problem and not well understood how to affect the high cycle fatigue (HCF) failures in gas turbine engine and other machinery. Most researchers conducted on the subject of only two bodies in contact with the Coulomb’s friction law only. In this paper, the interface friction phenomena and induced vibration are investigated by means of the improved third-body composite interface micro-slip model which includes a variable friction coefficient and a flexible contact, represented as effective stiffness and equivalent viscous damping elements. The third-body considered herein is almost always present at contacting interfaces and is comprised of generated wear debris or a soft intermediate anti-fretting coating applied to the mating surfaces. This kind of third-body can be viewed as a thin factional damping material layer to provide shear energy dissipation in order to mitigate the destructive effects of high frequency vibrations in components with highly stressed contacts. A properly engineered third-body can also play the role of both a damping material and a lubricant to decrease wear rate.
For the study presented, a semi-empirical formula for the third-body powder properties was employed, depending on the experimental data and the non-linear regression approach. The experimental powder TiO2 data included density, shear strength, frictional coefficients, loss factor as a function of normal load, shear strain, speed and frequency. The results in this paper indicate that the third body semi-empirical equivalent stiffness / viscous damping representation of a flexible contact with variable friction coefficient does indeed have merit and does have influence on overall system response. It has been shown that the third body effects should be considered in the friction and damping induced vibration on the contact interfaces. Such a model may be used to assess designs and material coating approaches to counter fretting in highly stressed contacts as well as assessing the interaction of contact kinematics on HCF failures. Further experimental investigation of specified friction contact configuration of the components needs to be conducted in order to evaluate their friction characteristics and move this technology toward a practical engineering applications.