bluuebunny/crossref_metadata_2025 huggingface dataset:
Perceiving Surface Roughness Through a Probe: Effects of Applied Force and Probe Diameter
Authors: Lederman Susan J. , Klatzky Roberta L. , Hamilton Cheryl , Grindley Molly
Published: November 2021

The current paper constitutes a continuation of our psychophysical research on perceiving the surface roughness of raised-dot surfaces via a rigid probe. Here we investigated the perceptual consequences of varying applied force (Experiment 1) and probe diameter (Experiment 2). A passive-touch mode was used to effect contact between probe and surface. All psychophysical roughness functions were best fit by quadratic equations. Increasing force resulted in increased roughness estimates, without a corresponding shift in the peak position of the function along the interelement-spacing axis (Experiment 1). Perceived roughness decreased overall with increasing probe diameter for the narrower interelement spacings; however, perceived roughness increased overall with increasing probe diameter for the wider interelement spacings. This reversal was explained by a corresponding shift in the position of the peaks of the psychophysical functions toward the wider end of the interelement-spacing axis as probe diameter increased (Experiment 2). Implications for the design of haptic interfaces for virtual environments are also considered.

In the last couple of years, we have been reporting the results of a comprehensive research program investigating how people perceive surface texture via a rigid probe. The initial and current stage of this research program involves conducting psychophysical experiments to determine a small number of critical parameters that will describe how vibration — induced by the interaction between surface and rigid probe, and passed to the skin — leads to an internal representation of surface roughness. In the second stage of this research program, we intend to develop a model that describes texture perception from a probe as the transition from mechanical interactions between probe tip and surface to perceptual responses. In the third stage of the program, we will use the vibration based model to create virtual textures with a haptic-interface by delivering vibratory forces to the fingertip.

We begin by reviewing the psychophysical literature on perceiving roughness via the bare finger versus a rigid probe as intermediary.
On the Use of Two Channels for Bilateral Telemanipulation
Authors: Fite Kevin B. , Speich John E. , Goldfarb Michael
Published: November 2021

A two-channel architecture is presented for the control of a bilateral telemanipulation system. The use of two channels enables the authors to cast the control problem in a classical unity-feedback control loop form, which in turn enables the use of frequency-domain loop shaping techniques. Specifically, the human-manipulators-environment loop can be supplemented with a compensator of a lead/lag form, which can be utilized to simultaneously increase the stability robustness and the transparency bandwidth of the system. This design approach is illustrated with a single-degree-of-freedom example.
Effect of Electrode Geometry and Intensity Control Method on Comfort of Electrotactile Stimulation on the Tongue
Authors: Kaczmarek Kurt A. , Tyler Mitchell E.
Published: November 2021

Electrotactile (electrocutaneous) stimulation for sensory substitution and augmentation possesses a variety of sensory attributes, including intensity, pitch, and more qualitative factors relating to the degree of comfort or discomfort of the stimulus. This study examined the roles of electrode geometry (size and presence or absence of a coaxial ground plane), and intensity control method (voltage or current), on the relative comfort of the electrotactile stimulus on the tongue. Only electrode size was found to significantly affect comfort, with larger electrodes resulting in more preferable percepts.
Comparison of Teleoperator Control Architectures for Palpation Task
Authors: Sherman Alana , Çavuşoğlu Murat Cenk , Tendick Frank
Published: November 2021

This work focuses on the design and testing of teleoperation controllers which are required to discriminate changes in compliance, addressing the question of which controller architecture performs the best in the high fidelity application of telesurgery. Three teleoperator controller architectures are compared for their ability to detect objects in compliant environments. These architectures are: position error based force feedback (PERR), kinesthetic force feedback (KFF), and position and force feedback (P+FF). The gains for each controller are chosen based on stability, tracking performance, and fidelity of the system. Stability is determined by a robust stability criterion. A sensitivity function is used to determine a tracking criterion. A new fidelity measure is introduced which looks at the sensitivity of the transmitted impedance to changes in the environmental compliance. Experiments are conducted to determine which control architecture allows the operator to most easily determine a change in compliance. This experimental task is designed to mimic palpation of soft tissue performed in medical procedures. The results suggest that the hybrid controller (P+FF) outperforms both PERR and KFF.
Telemanipulator for Dexterity Enhanced Laparoscopic Surgery Based on the Direct Coupling of Two Parallel Mechanisms
Authors: Reboulet Claude , Theron Alain
Published: November 2021

This paper deals with the design of a mechanism based on a new kinematics which behaves as a master slave manipulator. Thanks to a direct mechanical coupling, this telemanipulator is easy and cheap to build, since it requires neither sensor nor actuator. Moreover this new mechanism, based on a redundant parallel structure, is well adapted to surgical applications or more generally to all tasks requiring micro-manipulation. Finally, a relationship between some global performance index and the capability of kinesthetic feedback, is shown.
A Translational-to-Rotational Continuously Variable Transmission Element for a Parallel Cobot
Authors: Emrich Richard , Hodgson Antony J.
Published: November 2021

Cobots are inherently passive devices which constrain the motions of an end-effector powered by external means (often a human user). Previous cobot designs have relied either on a wheel or a rotational continuously variable transmission (CVT) to couple joint velocities; these elements are best suited to planar or serial manipulator designs. In this paper, we describe the design of a new CVT mechanism which is well suited for parallel manipulators and outline a potential application in computer-assisted surgery.
Actuator Array for Display of Distributed Tactile Information: Design and Preliminary Experiments
Authors: Kammermeier Peter , Buss Martin , Schmidt Günther
Published: November 2021

In this paper we present the design of a new tactile actuator array for the display of distributed tactile dynamic shape information in telepresence and Virtual Environment (VE) applications. In actuator design we focussed on high pin forces and a bandwidth sufficient for most one-fingered tactile shape exploration tasks performed by dynamic interaction. As a result, the overall device dimensions currently prohibit its attachment to the effector of typical kinesthetic feedback devices. Experimental results are presented using the prototype in a finger-on-conveyer-belt scenario with objects moving relative to a resting fingertip. Experiments showed that the dynamic tactile display enabled probands to give parameter estimates of displayed objects with an accuracy exceeding the pin resolution of the tactile feedback device.
Finite Element Stress Response Analysis of Stepped-Lap Adhesive Joints Subjected to Impact Tensile Load
Authors: Sawa Toshiyuki , Ohmori Takahiro
Published: November 2021

The stress wave propagation and the stress distribution in stepped-lap adhesive joints of similar adherends subjected to impact tensile loads and elastic deformation are analyzed using three-dimensional finite-element method (FEM). The impact load is applied to the joint by dropping a weight. One end of the upper adherend is fixed, and the other end of the lower adherend is subjected to an impact load. FEM code employed is DYNA3D. The effects of Young’s modulus of the adherends, the number of lapped steps, and the adhesive thickness on the stress wave propagation at the lapped, and fee butted interfaces are examined. It is also found that the maximum value of the maximum principal stress σ1 occurs at the end of the butted interface between the adhesive and the lower adherend to which the impact load is applied. As the number of the lapped steps increases, the maximum value of the maximum principal stress σ1 increases. It is found that the maximum value of the maximum principal stress σ1 increases as the adhesive thickness decreases. The maximum value of σ1 increases as Young’s modulus of the adherends increases. In addition, the experiments were carried out to measure the strain response of stepped-lap adhesive joints subjected to impact tensile loads using strain gauges. A fairly good agreement is seen between the analytical, and the experimental results.
Mathematical Modeling of Seat and Occupant Interaction in Rear Impact
Authors: Chai Li , Barbat Saeed D.
Published: November 2021

Automobile occupant injuries related to rear-end collisions have become the most expensive insurance claims even though fatality rate is relatively low compared to other types of injuries. The concept of designing seats for safety has caught the attention of researchers in recent years. The finite element analysis (FEA) technique has been used as an efficient tool in vehicle safety technology development, but limited work has been reported in its application to seat design for safety. In this paper, a seat/dummy FEA model is developed and presented. The seat geometry is accurately generated from CAD data. The material properties of the seat foams are derived from tests. The seat/dummy model is validated against sled tests in 16 kph and 40 kph rear impact modes. The predicted dummy responses in terms of head acceleration, neck forces and moments, chest acceleration, lumbar spine force and moment, and pelvis acceleration are discussed. Model predictions are favorably correlated with tests. Therefore, this model can be deemed as ready for rear impact studies.
Adipose Tissue-Derived Stromal Cells Grown in Three-Dimensional Aliginate Constructs Display a Chondrogenic Phenotype
Authors: Erickson Geoffrey R. , Gimble Jeffrey M. , Franklin Dawn , Guilak Farshid
Published: November 2021

Articular cartilage is the connective tissue that lines the surfaces of diarthrodial joints in the human body. Because cartilage is avascular, aneural, and alymphatic, it has a limited capacity for repair. Techniques such as microfracture, transplantation of autologous cartilage, and allograft or xenograft transplantations have not proven fully effective in treating cartilage damage. Current therapy is focusing on cell-based treatments such as autologous chondrocyte transplantation [1,2]. However, this method faces several limitations, as the donor site can provide a limited number of cells and the harvesting procedure itself may cause significant local morbidity. The goal of this study was to examine the chondrogenic potential of an autologous source of undifferentiated stromal cells derived from subcutaneous fat. It has been shown that chondrocytes embedded in a three-dimensional matrix retain a differentiated phenotype and produce cartilage-associated proteins [3]. In addition, it has been shown that alginate or agarose can support the formation of an extracellular matrix over time [4,5]. The goal of this study was to examine the chondrogenic potential of adipose-derived stromal cells with the ultimate goal of developing a “tissue engineering” method to regenerate articular cartilage.
Development of Tissue-Engineered Human Articular Cartilage
Authors: Applegate Mark A.
Published: November 2021

Disability due to joint pain is increasing as our society ages. This pain often results from cartilage degeneration in joints due to osteoarthritis or trauma. Cartilage damage from sports injuries is common and the normal repair response results in the formation of fibrous tissue that is inferior to normal cartilage in structure and function and eventually degenerates with time. As a result, tens of thousands of total knee replacements and other surgical procedures are performed each year to repair cartilage defects in the knee. A common clinical treatment for cartilage lesions is debridement of the damaged tissue followed by drilling into the subchondral bone to stimulate tissue regeneration. Although this procedure often provides pain relief, it does not restore long-term function and frequently hastens additional degeneration of the injured site. Alternative procedures for repair or regeneration of human articular cartilage are needed.
Measuring Cellular Forces Using BioMEMS
Authors: LeDuc Philip , LaVan David , Bao Gang
Published: November 2021

In recent years cellular biomechanics has attracted much attention in various fields including biology, medicine, and engineering. Although the ability of a cell to sense and respond to mechanical forces is a focus of many investigations, determining the specifics of how a mechanical stimulus directly affects the behavior and function of a living cell remains a daunting task. Here, by combining the chip technology that is able to create structures on the same size scale as cells, a biological microelectromechanical systems (BioMEMS) device is developed and utilized to study the force generation, local perturbation and deformation of a single cell.
Moment Arm Calculations From In-Vivo Kinematic Data: Applications to the Trapezius Muscle
Authors: Karduna Andrew R. , McClure Phil W.
Published: November 2021

Alterations in scapular movement patterns are believed to be associated with muscle weakness, fatigue, and paralysis. Due to the control that muscles exert on scapular position, it is important to understand their mechanical efficiency. Previous researchers have used the principle of virtual work to assess shoulder muscle moment arms, but these studies have focused on the glenohumeral joint [1,2]. The purpose of this investigation was to develop an approach for studying scapular muscle moment arms - specifically focusing on the middle and upper trapezius.
Loading Evaluation of Knee Joint During Walking Using the Next Generation Knee Simulator
Authors: Maletsky Lorin P. , Hillberry Ben M.
Published: November 2021

Even with the advances in material selection, processing, and articular geometry for knee prostheses, there is still a need for in vitro evaluation of these components. The high occurrence of revision surgeries for failed prosthetics suggests that the component designs can still be improved. While historically the typical total knee recipient was an elderly woman, components are being implanted in younger patients who wish to lead more active lives with their new artificial knees. Therefore, the testing of new prostheses must be more rigorous and demanding than done previously. For these reasons a new five-axis electro-hydraulic knee simulator was constructed.
Biomechanical Analysis of Coronary Arteries Using Designed Experiments and a Complementary Energy Model
Authors: Dixon Stacey A. , Vito Raymond P. , Heikes Russell G.
Published: November 2021

To assist in the design of a compliant coronary vascular graft, a constitutive equation predicting the biomechanical properties of healthy coronary arteries was determined. An experimental design in the physiological range of force and pressure was used to improve data collection. Using a logarithmic complementary energy formulation of the constitutive equation resulted in an exceptional fit to the data. Comparisons showed statistically significant differences between the porcine left anterior descending [LAD] and right coronary artery [RCA] (p<0.02) but no differences between the left circumflex [LCX] and LAD or LCX and RCA (p>0.05).
Preliminary Design Considerations and Feasibility of a Biomimicking Tissue-Engineered Vascular Graft
Authors: Stitzel Joel D. , Bowlin Gary L.
Published: November 2021

Development of an ideal vascular replacement has been addressed with increasing urgency in recent years. To date, appropriate replacements for only large diameter bypass grafts have been realized, employing the use of Dacron and expanded polytetrafluoroethylene. A solution for small diameter (<6 mm I.D.) vessel bypass, however, has not yet been found. This is due mainly to acute thrombotic occlusion and chronic anastomotic hyperplasia that is introduced into these grafts due to the low blood flow velocities experienced by smaller caliber vessels and compliance mismatch between prosthetic and native vessel, respectively [1].
Material Properties of Abdominal Aortic Aneurysm Wall From Uniaxial Tests
Authors: Thubrikar Mano J. , Labrosse Michel , Al-Soudi Jihad , Fowler Brett , Robicsek Francis
Published: November 2021

Abdominal aortic aneurysms (AAA) rupture when the aortic wall cannot withstand the stresses and strains induced by the pulsatile blood pressure. In recent years, different mechanical models of aneurysms have been presented (Vorp et al., 1998, Di Martino et al., 1998, Thubrikar et al., 1999). Although powerful modeling tools such as finite elements are available, there is still a need for experimental data concerning the mechanical properties of the aneurysm wall.
Effect of Initial Tube Strain on Self-Excited Oscillation of Collapsible Tube Flow
Authors: Xia Yupeng , Hayase Toshiyuki , Hayashi Satoru , Hamaya Tsuyoshi
Published: November 2021

Since human organs, such as blood vessels, tracheas and urethras, have similar characteristics to collapsible tubes, a lot of studies on both steady and unsteady flow through the collapsible tubes have been done in biological and physiological fields [1, 2]. Recently, Sakurai et al carried out an experimental analysis concerning the effect of longitudinal tension on collapsible tube flow [3]. However, the real figure of this complex system, including the influence of the tube parameters on self-excited oscillation is still not sufficiently understood. In present report an experiment was performed to investigate the dynamic characteristics of a collapsible tube flow. The effect of initial axial strain of the tube on the self-excited oscillation was studied by changing the initial stretch of a thin-walled silicone rubber tube for various values of supply flow rate.
Development of a Tibial Slider to Evaluate and Validate a Finite Element Model for Friction in Total Knee Implants
Authors: Nowak Michael D. , Shaw Kenneth , Lewis Courtland
Published: November 2021

More than 200,000 people in the United States annually undergo knee replacement as a means of diminishing pain and stiffness and restoring mobility, and the number is expected to increase with further advancements in joint replacement procedures [Duke, 1999]. Total knee replacement is performed on people with severe degenerative joint disorder such as osteoarthritis in which the articular surfaces of the knee deteriorate, leading to severe pain, limitation or loss of function and/or deformity of the joint.
Finite Element Simulation of Cartilage Mechanics During Diarthrodial Joint Motion Using Physiological Data
Authors: Ün Kerem , Donzelli Peter S. , Spilker Robert L.
Published: November 2021

Moving contact is fundamental to understanding the mechanical environment of articular cartilage in diarthrodial joints. This study presents a method for approximating three-dimensional (3D) moving contact of biphasic tissue layers using a time-dependent penetration method. This technique has been implemented in a custom finite element solution framework for large-scale simulation that includes a graphical user interface, automatic meshing, and visualization tools. Thus, physiological geometry and load levels can be simulated by this approximate technique. The method is illustrated for canonical and physiological problems representing the glenohumeral joint (GHJ) of the shoulder.
A Method to Calculate Volumetric Integral Averages From a Finite Element Solution
Authors: Miller Echo M. , Donzelli Peter S. , Spilker Robert L.
Published: November 2021

The inhomogeneity and anisotropy of articular cartilage has been experimentally verified, but little has been done to quantify the effects of such material variation on mechanical behavior. We present a method to calculate volume-averaged quantities over tissue regions, used in conjunction with a 3D biphasic finite element analysis. Such average quantities can be used in parametric studies of different material property models, readily permitting statistical comparisons that are difficult with point-wise quantities.
Study of Ho:YAG Laser Generated Underwater Shock Waves and Cavity Bubble for Revascularization Therapy
Authors: Hosseini S. H. R. , Hirano T. , Onodera O. , Takayama K.
Published: November 2021

For applying shock waves to precise medical procedures like neurosurgery, a reliable generation of micro shock waves is required. Such sensitive applications make limits on usage of conventional underwater shock wave sources like Extracoporeal Shock Waves ESW [1] or micro explosives [2]. In the present study a Q-switched Ho:YAG laser and an optical fiber are used. Advantages of this method over previous shock wave sources are two order of magnitude reduction in focusing area if compared with ESW and elimination of product gases of micro explosives. Nakahara and Nagayama [3] studied underwater shock waves emanated from surface of an optical fiber by pulse Nd:YAG laser input using shadowgraph technique. Their qualitative study limited to visualization of shock waves at its early stage. The present research aims to clarify quantitatively process of the shock wave generation by direct laser beam irradiation through optical fibers, growth and behavior of generated cavities, and structure of heat induced flow in front of the optical fiber.
In Vitro Stain Transport in Canaliculi of Rat Femora Under Cyclic Loading
Authors: Li Bixia , Norman Timothy L.
Published: November 2021

In this study, rat femurs were used to test the diffusion and mechanical transport properties of a fluroscein stain tracer in microvessels of bone. Fluroscein was used as a tracer to visualize the fluid flow behavior using confocal microscopy. It was found that stain transport occurs due to diffusion under static conditions and due to mechanical loading. The transport increased with cyclic load level and frequency. Our results also show that stain transport at the canaliculi level occurs rapidly in rat bone.
Vehicle Crashworthiness in Vertical Drop Tests
Authors: Herbst Brian , Forrest Steven , Meyer Steven E. , Chng David , Davis Mark , Sances Anthony
Published: November 2021

Inverted drop testing of vehicles is a methodology that has long been used by the automotive industry and by researchers to test roof integrity. In our laboratory, the inverted drop test methodology was employed on a late model production sport utility vehicle (SUV) in order to simulate the damage incurred by a real world rollover accident. The extent and shape of residual damage matched well with the accident damage. A second vehicle was reinforced based upon techniques and methods published by Herbst et al1, which reduced the crush from 11″ to 2.75″. Incorporation of these techniques demonstrated an increase in roof strength of approximately four-fold with a minor weight addition. The modified vehicle was dropped a second time for a cumulative drop height of 3 feet. The modified vehicle after the second test crushed approximately 3–4″ over the driver seating location and 7″ at the top of the driver’s A-pillar.
The Effect of Vertical Acceleration on Emergency Locking Seatbelt Retractors
Authors: Meyer Steven E. , Forrest Stephen , Hayden Joshua , Herbst Brian , Sances Anthony
Published: November 2021

Contemporary production seatbelt retractors have been proven very effective in the crash environment for which they have been primarily designed and most adequately tested, that is, in the full frontal crash mode. The National Traffic and Motor Vehicle Safety Act of 1966 outlines specific crash test and occupant injury measure requirements for testing and evaluation of seatbelt systems in production vehicles. Automobile manufacturers routinely test exhaustively in compliance of these requirements with respect to full frontal barrier crashes. However, government requirements are not nearly as complete for alternative accident modes often seen in the real world. Offset, angled, override, underride, and rollover crashes will often require seatbelt retractors to manage acceleration pulses in varying directions, including the vertical plane. Occupant motions during these real world accident modes may also impart loads into the belts and belt hardware (webbing and buckle assemblies) that also may not be immediately apparent in the frontal barrier test mode.
Influence of Graft/Host Diameter Ratio on the Hemodynamics in Sequential ITA Anastomoses
Authors: Bonert Michael , Myers Jerry G. , Fremes Stephen E. , Ethier C. Ross
Published: November 2021

Multivessel grafting with internal thoracic artery (ITA) conduits may improve the long-term results of coronary surgery for patients with multivessel coronary disease. Sequential ITA grafting has been increasingly used as a means of allowing a single ITA to revascularize a greater amount of the myocardium (Izzat et al, 1994). In this procedure, the graft first supplies blood to a coronary artery via a side-to-side anastomoses and then delivers blood to a second site in the coronary vasculature through an end-to-side anastomosis. However, it is unclear if the complex geometry and hemodynamic patterns in the side-to-side anastomosis contribute to the development of intimal hyperplasia, as reported for end-to-side anastomoses (Bassiouny et al. 1992). In a previous study we studied the hemodynamics of side-to-side anastomosis when graft and host diameters are equal (Bonert et al., 1999). In this study, we examined the wall shear stress (WSS) characteristics in idealized models of a “parallel” and a “diamond” side-to-side anastomoses for the case in which the graft diameter is substantially larger than the host diameter (Lei et al., 1996). Regions of specific interest were those exhibiting low WSS and rapidly changing WSS (high spatial WSS gradient) both of which have been suggested to promote intimal hyperplasia.
Hydrodynamic Modeling of Cerebrospinal Fluid Motion Within the Spinal Cavity
Authors: Yardimci M. Atif , Loth Francis , Alperin Noam
Published: November 2021

In the present work, a geometric and hydrodynamic characterization of an anatomically relevant spinal canal model is presented. A numerical model was employed to investigate effects of cross-sectional geometry and spinal cord motion on unsteady velocity, shear stress, and pressure gradient fields. The velocity field was shown to be blunt, due to the inertial character of the flow, with velocity peaks located near the boundaries of the spinal canal rather than at the midpoint between boundaries. The pressure gradient waveform was found to be almost exclusively dependent on the flow waveform and cross-sectional area.
Influence of Zeta Potential on the Lubrication Between Ultra-High Molecular Weight Polyethylene and CoCrMo Alloy
Authors: Kitano Toshio
Published: November 2021

Zeta potential is the potential that is related to the electric charge of the surface. Zeta potential influences tribological surface phenomenons. In the field of Orthopaedic surgery, osteolysis due to wear debris is one of the most difficult complications following total joint arthroplasty. Improvement of long term results and decrease of the revision rate demand that the lubrication mechanism of total replacement joint be revealed and friction and wear of surface be reduced. The purpose of this study is to clarify the correlation between zeta potential of ultra-high molecular weight polyethylene (UHMWPE) and friction in total replacement joint under boundary lubrication condition and to answer the effect of glycoprotein on total replacement joint.
A Study of Hydroforming for Processing Composites
Authors: Zampaloni Michael A. , Pourboghrat Farhang , Benard Andre
Published: November 2021

The use of hydroforming to shape complex composite parts is proposed in this work. Hydroforming is expected to greatly increase the formability of composite sheet by the use of a controllable heated, pressurized fluid. Hydroforming, in comparison with sheet stamping, is a more economical manufacturing process, since it does not require the use of a female die. The pressurized fluid acts as a support for the composite sheet throughout the forming process. A numerical analysis has been performed on this process in order to develop a method of predicting the final part geometry. The numerical analysis takes into account the pressurized fluid, the thermal effects, and the clamping mechanism used to hold the material in place as the part is formed. Numerical results show that using hydroforming for manufacturing glass fiber reinforced polypropylene composite material significantly reduces the strain, especially within the cup region of the hemispherical part. The fluid pressure also has an effect on the internal stresses of the part by allowing deeper draws before rupture. The experimentation, coupled with the prediction of the finite element modeling, indicates that the hydroforming of composite materials is a viable processing method that deserves more attention based on the significant advantages it provides in cost savings and part production accuracy.
Cautionary Aspects of Applied Probabilistics
Authors: Annis Charles
Published: November 2021

The idea of probabilistic engineering analysis — replacing fixed values for important parameters with their probability densities — seems almost self-evident. With the arrival of increasingly inexpensive computing capacity the past decade has witnessed a great proliferation of such analysis. Regrettably, however, much of this is unwittingly constructed on untenable statistical premises. Engineers, sure of their subsequent logic, can arrive at grossly erroneous conclusions, not always because their engineering is flawed, but because they relied on statistical assumptions that do not hold in their situation, or overlooked statistical results that do.
Probabilistic Micromechanical Fatigue Model for High Temperature Materials
Authors: Tryon Robert G.
Published: November 2021

The paper discusses an enhanced analytical modeling approach to characterize and understand fatigue crack initiation and growth in gas turbine engine intermetallics. It is recognized that the design of components subjected to fatigue cannot be based on average material behavior but that designs must consider −3σ or some other appropriate extreme value material properties. Thus, a life prediction capability useful in a design application must address the scatter inherent in material response to fatigue. The paper addresses the scatter in fatigue life of gamma titanium aluminide by investigating the microstructural variables responsible for the scatter and developing analytical and semi-analytical models to quantitatively relate the variables to the response. The model is general and considers the entire range of damage accumulation sequences; from crack nucleation of the initially unflawed structure to final fast fracture. However, the model also allows failure to be defined as any subset of damage accumulation i.e., crack initiation life to a particular crack size or the number of cycles to grow a crack from a particular size to final fracture. The models allows the structural engineer to systematically and quantitatively assess the influence of the material uncertainties on the overall reliability of the structure.
Functional Analysis of Bone-Biomaterial Interface
Authors: Tuan Rocky S.
Published: November 2021

Proper function and long-term stability of orthopaedic implants depend on the intimate association between bone cells and the implant biomaterial, a process known as osseointegration. Understanding the processes responsible for the establishment and maintenance of a functional bone-biomaterial interface and how these processes may be enhanced is crucial to the rational design and optimization of prosthetic devices. We have utilized cellular, molecular, and high-resolution imaging approaches to analyze the mechanistic basis of bone-biomaterial interactions. Specifically, we have characterized the initial adhesion of osteoblasts in terms of kinetics and relationship to the surface topography and chemistry of the biomaterials, particularly the cobalt-chrome and titanium alloys commonly used to fabricate orthopaedic prostheses. Results from these studies indicate that the long-term performance of osteoblasts adherent to biomaterials is crucially dependent on the characteristics of the initial adhesion step. Furthermore, osteoactive factors such as members of the transforming growth factor-β superfamily, including TGF-β1 and BMP-2, significantly enhance osteoblast cell adhesion. The molecular components responsible for the adhesion process include extracellular matrix proteins (e.g. fibronectin and collagen type I) and their cognate membrane receptors, the integrins. Our recent studies reveal that specific downstream, intracellular signaling events are also activated as a result of osteoblast adhesion, and that these signaling events are coupled to signal transduction mechanisms mediating growth factor activity. These events in combination regulate the continued expression and maintenance of the osteoblastic phenotype of the adherent cells, resulting in matrix maturation and mineralization, hallmarks of the bony tissue. Our current efforts focus on defining the target molecular pathways responsible for bone cell functioning on biomaterials, and the identification of critical biological and material parameters to optimize long-term osteoblast function and interaction with orthopaedically relevant biomaterials. The information gathered from these studies should provide a rational basis for the design of optimal implant biomaterials. (Supported in part by the NIH and the Annenberg Foundation)
An Investigation of the Effects of Isothermal Exposure on Microstructural Evolution and Oxidation in a Thermal Barrier Coating
Authors: Chang T. , Mercer C. , Walter M. E. , Soboyejo W. O.
Published: November 2021

This paper presents the results of a systematic investigation of the effects of isothermal exposure on the microstructural evolution and the isothermal oxidation behavior of a thermal barrier coating with a platinum aluminide bond coat. Sintering of the columnar partially stabilized zirconia is shown to occur during isothermal exposure at 1150°C for durations up to 200 hours. This is accompanied by roughening of the TGO layers, the formation of hemi-spheroidal defects, parabolic coarsening of the TGO and final pull-out of the zirconia layers. The implications of the results are discussed for the analysis and design of TBCs for aeroengine applications.
Measurements of Decomposed EPS Gases Pressure and Molten Metal-Polymeric Foam Interface Velocity During Lost Foam Casting Process: Part 1—Disconnect Casting
Authors: Bakhtiyarov Sayavur I. , Overfelt Ruel A.
Published: November 2021

Process parameters of lost foam casting were studied experimentally on a commercial scale for two casting techniques: conventional and vacuum assisted gravity castings. The paper presents the results of the foundry experiments focused on the time and spatial dependent aspects of mold filling of a commercial pattern (Disconnect). A small-scale commercial model was designed and fabricated to conduct the experiments to study the thermo- and hydrodynamics of the mold filling characteristics. A high sensitivity linear output capacitive sensor was used to record the rate of sand flow and compaction in flask while horizontal and/or vertical vibrations were applied. A computer aided thermometric technique was used to study the heat-related processes in the counter-gravity lost foam vacuum casting. A complete pattern of vacuum/pressure fluctuations is obtained during counter-gravity vacuum casting using bi-directional vacuum/pressure transducer. Tolerance analyses were performed for styrofoam patterns and their cast products produced by the conventional and vacuum assisted casting procedures.
Dynamic variability in SHP-1 abundance determines natural killer cell responsiveness
Authors: Wu Zeguang , Park Soo , Lau Colleen M. , Zhong Yi , Sheppard Sam , Sun Joseph C. , Das Jayajit , Altan-Bonnet Grégoire , Hsu Katharine C.
Published: November 2021

The responsiveness of mouse and human natural killer cells is inversely correlated with the abundance of the phosphatase SHP-1.
Targeting ischemia-induced KCC2 hypofunction rescues refractory neonatal seizures and mitigates epileptogenesis in a mouse model
Authors: Sullivan Brennan J. , Kipnis Pavel A. , Carter Brandon M. , Shao Li-Rong , Kadam Shilpa D.
Published: November 2021

The drug CLP290 may treat neonatal seizures by acutely enhancing the function of K
+
/Cl
−
cotransporter KCC2.
Resistance may be futile
Authors: Baek Amy E.
Published: November 2021

Tumor-associated macrophages evade CSF1R inhibition through a compensatory CSFR2b-STAT5 pathway.
The Stringent Response Inhibits 70S Ribosome Formation in
Staphylococcus aureus
by Impeding GTPase-Ribosome Interactions
Authors: Bennison Daniel J. , Nakamoto Jose A. , Craggs Timothy D. , Milón Pohl , Rafferty John B. , Corrigan Rebecca M.
Published: November 2021

The stringent response is a bacterial signaling network that utilizes the nucleotides pppGpp and ppGpp to reprogram cells in order to survive nutritional stresses. However, much about how these important nucleotides control cellular reprogramming is unknown.
Heparanase-Induced Activation of AKT Stabilizes β-Catenin and Modulates Wnt/β-Catenin Signaling during Herpes Simplex Virus 1 Infection
Authors: Koujah Lulia , Madavaraju Krishnaraju , Agelidis Alex M. , Patil Chandrashekhar D. , Shukla Deepak
Published: November 2021

Heparanase (HPSE) and β-catenin have independently been implicated in regulating key pathophysiological processes, including neovascularization, angiogenesis, and inflammation; however, the relationship between the two proteins has remained elusive thus far. For that reason, characterizing this relationship is crucial and can lead to the development of novel therapeutics.
Centennial to millennial variability of greenhouse climate across the mid-Cenomanian event
Authors: Ma Chao , Hinnov Linda A. , Eldrett James S. , Meyers Stephen R. , Bergman Steven C. , Minisini Daniel , Lutz Brendan
Published: November 2021

Centennial- to millennial-scale climate variations are often attributed to solar forcing or internal climate system variability, but recognition of such variations in the deep-time paleoclimate record is extremely rare. We present an exceptionally well-preserved, millimeter-scale laminated marlstone from a succession of precession-driven limestone-marlstone couplets deposited in the Western Interior Seaway (North America) immediately preceding and during the Cretaceous mid-Cenomanian event (ca. 96.5 Ma). Sedimentological, geochemical, and micropaleontological data indicate that individual pairs of light-dark laminae record alternations in the extent of water-column mixing and oxygenation. Principal component analysis of X-ray fluorescence element counts and a grayscale scan of a continuous thin section through the marlstone reveal variations with 80–100 yr, 200–230 yr, 350–500 yr, ∼1650 yr, and 4843 yr periodicities. A substantial fraction of the data indicates an anoxic bottom water variation with a pronounced 10,784 yr cycle. The centennial to millennial variations are reminiscent of those found in Holocene total solar irradiance variability, and the 10,784 yr anoxia cycle may be a manifestation of semi-precession-influenced Tethyan oxygen minimum zone waters entering the seaway.
Evaluating preservation bias in the continental growth record against the monazite archive
Authors: Mulder Jacob A. , Cawood Peter A.
Published: November 2021

Most recent models of continental growth are based on large global compilations of detrital zircon ages, which preserve a distinctly episodic record of crust formation over billion-year timescales. However, it remains unclear whether this uneven distribution of zircon ages reflects a true episodicity in the generation of continental crust through time or is an artifact of the selective preservation of crust isolated in the interior of collisional orogens. We address this issue by analyzing a new global compilation of monazite ages (n >100,000), which is comparable in size, temporal resolution, and spatial distribution to the zircon continental growth record and unambiguously records collisional orogenesis. We demonstrate that the global monazite and zircon age distributions are strongly correlated throughout most of Earth history, implying a link between collisional orogenesis and the preserved record of continental growth. Our findings support the interpretation that the continental crust provides a preservational, rather than generational, archive of crustal growth.
Graves’ disease associated with cholestatic jaundice and persistent diarrhoea
Authors: Rane Siddhesh Vijay , Thanage Ravi , Chandnani Sanjay , Rathi Pravin M
Published: November 2021

Liver involvement in Graves’ disease can be seen as a part of autoimmune process or rarely, due to the direct effects of thyrotoxicosis on liver. Hyperthyroidism can also have gastrointestinal manifestations like frequent bowel movements, diarrhoea, even malabsorption with steatorrhoea. We report a 36-year-old man with hyperthyroidism, presenting with cholestatic jaundice and persistent small bowel diarrhoea. He was diagnosed to have Graves’ disease and after ruling out more common causes, the cause of cholestatic jaundice was supposed to be Graves’ disease. Considering this possibility, the patient was started on treatment with carbimazole. As patient’s thyroid function tests started improving, he showed significant clinical and biochemical improvement from liver point of view as well.
Calvarial tuberculosis in a paediatric patient: a diagnosis not to forget
Authors: Dias Raquel Baptista , Rosa Joaninha Costa , Caldas Gabriela Baptista , Borges Alexandra
Published: November 2021

We report the case of a 10-year-old boy that presented with a palpable, painless, frontal lesion. Laboratory assessments were unremarkable and the patient was asymptomatic. Initial investigation, with a skull radiograph and unenhanced CT scan, showed a lytic midline frontal lesion involving the inner and outer tables of the skull and a large subgaleal hypodense component. MRI further depicted communication with the epidural space and contact with the superior sagittal sinus (SSS). Subsequent evaluation by Doppler ultrasound and MR angiography excluded a sinus pericranii and showed normal patency of the SSS. Surgical biopsy revealed chronic granulomatous inflammation; PCR was positive forMycobacteriumsp. One year after surgical resection and antitubercular therapy, there are no signs of recurrence. Primary calvarial involvement by tuberculosis is rare, even in developing countries. Familiarity with the expected clinical and imaging features is required to avoid diagnostic delay.
21 Neutrophil extracellular traps (NETs) can be measured non-invasively with CPa9-HNE – biomarker potential across different solid tumor types in the immuno-oncology setting
Authors: Jensen Christina , Thorlacius-Ussing Jeppe , Mortensen Joachim , Karsdal Morten , Willumsen Nicholas
Published: November 2021

Background

Serological predictive biomarkers to anti-PD-1 therapy across different solid tumor types represent an unmet medical need. High neutrophil activity is associated with poor response to immune checkpoint inhibitor therapy, amongst others due to the release of neutrophil extracellular traps (NETs) that have been shown to protect tumor cells against cytotoxic attacks. Human neutrophil elastase (HNE) and calprotectin are the major NETs constituents. We have previously shown that high levels of a serum calprotectin assay, which quantifies a specific HNE generated calprotectin fragment (CPa9-HNE), as a measure of neutrophil activity, associate with poor response to anti-PD-1 therapy in metastatic melanoma patients. The aim of this study was to investigate the performance of CPa9-HNE in serum from patients with other solid tumor types.

Methods

HNE mediated degradation of calprotectin (CPa9-HNE) was measured in pretreatment serum from 223 patients with bladder cancer (n=20), breast cancer (n=20), colorectal cancer (n=20), head and neck cancer (n=20), kidney cancer (n=20), liver cancer (n=3), lung cancer (n=20), melanoma (n=20), ovarian cancer (n=20), pancreatic cancer (n=20), prostate cancer (n=20), and stomach cancer (n=20), and compared to age-matched healthy controls (n=33). Statistical differences were analyzed using the Kruskal-Wallis test adjusted for Dunn’s multiple comparisons test.

Results

CPa9-HNE serum levels were significantly elevated in patients with bladder cancer (p<0.0001), breast cancer (p<0.0001), colorectal cancer (p<0.0001), head and neck cancer (p<0.0001), kidney cancer (p<0.0001), lung cancer (p<0.0001), melanoma (p=0.0001), ovarian cancer (p<0.0001), pancreatic cancer (p<0.0001), prostate cancer (p=0.0009), and stomach cancer (p<0.0001) compared to healthy controls. In all solid tumor types, a large patient-to-patient variation was observed. CPa9-HNE was also significantly elevated in stage IV cancer patients compared to stage I cancer patients (p=0.044).

Conclusions

The novel serological biomarker CPa9-HNE measuring HNE mediated degradation of calprotectin is significantly elevated in patients with different solid tumor types suggesting that these patients have high neutrophil activity. As high neutrophil activity is associated with poor response to anti-PD-1 therapy, CPa9-HNE may be used as a biomarker for anti-PD-1 therapy across different solid tumor types.

Ethics Approval

The serum samples in this study was obtained from the commercial vendor Proteogenex and BioIVT, and according to the vendors, sample collection was approved by an Institutional Review Board or Independent Ethical Committee and patients gave their informed consent (Protocol numbers PG-ONC 2003/1 and WIRB® Protocol #20161665). All investigations were carried out according to the Helsinki Declaration.