bluuebunny/crossref_metadata_2025 huggingface dataset:
Fungal endophytes vary by species, tissue type, and life cycle stage in intertidal macroalgae
Authors: Bonthond Guido , Barilo Anastasiia , Allen Ro J. , Cunliffe Michael , Krueger‐Hadfield Stacy A.
Published: January 2022

Fungal symbionts of terrestrial plants are among the most widespread and well‐studied symbioses, relatively little is known about fungi that are associated with macroalgae. To fill the gap in marine fungal taxonomy, we combined simple culture methods with amplicon sequencing to characterize the fungal communities associated with three brown (Sargassum muticum, Pelvetia canaliculata, and Himanthalia elongata) and two red (Mastocarpus stellatus and Chondrus crispus) macroalgae from one intertidal zone. In addition to characterizing novel fungal diversity, we tested three hypotheses: fungal diversity and community composition vary (i) among species distributed at different tidal heights, (ii) among tissue types (apices, mid‐thallus, and stipe), and (iii) among “isomorphic” C. crispus life cycle stages. Almost 70% of our reads were classified as Ascomycota, 29% as Basidiomycota, and 1% that could not be classified to a phylum. Thirty fungal isolates were obtained, 18 of which were also detected with amplicon sequencing. Fungal communities differed by host and tissue type. Interestingly, P. canaliculata, a fucoid at the extreme high intertidal, did not show differences in fungal diversity across the thallus. As found in filamentous algal endophytes, fungal diversity varied among the three life cycle stages in C. crispus. Female gametophytes were also compositionally more dispersed as compared to the fewer variable tetrasporophytes and male gametophytes. We demonstrate the utility of combining relatively simple cultivation and sequencing approaches to characterize and study macroalgal–fungal associations and highlight the need to understand the role of fungi in near‐shore marine ecosystems.
Doing boss‐like tasks and worker well‐being: Job enrichment revisited
Authors: Asuyama Yoko
Published: January 2022

This study revisits the relationship between job enrichment and worker well‐being by analysing worker‐level data from around 20 countries. Job enrichment, which vertically expands jobs, is primarily measured by the novel ‘boss‐like tasks’ indicator, constructed from 42 task‐frequency data. The aim of job enrichment is to motivate workers. However, the study finds that even though average non‐boss workers doing more boss‐like tasks earn higher wages, they are not necessarily more satisfied with their jobs. The non‐positive or slightly negative association with satisfaction becomes positive when workers have low‐skilled blue‐collar jobs or when tasks involving planning and organizing are enriched.
Beethoven's Error? The Modulating Ritornello and the Type 5 Sonata in the Post‐Classical Piano Concerto
Authors: HORTON JULIAN
Published: January 2022

In his analysis of the first movement of Beethoven's Piano Concerto No. 3, Op. 37, Donald Francis Tovey dismissed Beethoven's decision to modulate for the second theme in the movement's opening tutti as an ‘error’ that gives the impression of a symphonic exposition rather than a concerto ritornello and thereby undermines the work's generic identity. For Tovey, Beethoven and practitioners falling under his influence misunderstood a fundamental formal principle, enshrined in Mozart's predominant habit of associating structural modulation with the solo exposition. More recent theories of concerto first‐movement form, including James Hepokoski and Warren Darcy's model of the ‘type‐5’ sonata, sustain both Tovey's view of Op. 37 and the normativity of Mozart's example. Drawing on a corpus study of 87 piano concerti by 20 composers written between 1789 and 1848, this paper challenges the centrality of the monotonal ritornello to the theory of the type 5 sonata. It demonstrates the overwhelming generic predominance of modulating ritornelli in this time and develops a post‐canonical theory of concerto first‐movement form that questions the centrality of Mozartian norms on historical and empirical grounds.
Teasing apart the unique contributions of cognitive and affective predictors of math performance
Authors: Silver Alex M. , Elliott Leanne , Reynvoet Bert , Sasanguie Delphine , Libertus Melissa E.
Published: January 2022

Math permeates everyday life, and math skills are linked to general educational attainment, income, career choice, likelihood of full‐time employment, and health and financial decision making. Thus, researchers have attempted to understand factors predicting math performance in order to identify ways of supporting math development. Work examining individual differences in math performance typically focuses on either cognitive predictors, including inhibitory control and the approximate number system (ANS; a nonsymbolic numerical comparison system), or affective predictors, like math anxiety. Studies with children suggest that these factors are interrelated, warranting examination of whether and how each uniquely and independently contributes to math performance in adulthood. Here, we examined how inhibitory control, the ANS, and math anxiety predicted college students’ math performance (n = 122, mean age = 19.70 years). Using structural equation modeling, we find that although inhibitory control and the ANS were closely related to each other, they did not predict math performance above and beyond the effects of the other while also controlling for math anxiety. Instead, math anxiety was the only unique predictor of math performance. These findings contradict previous results in children and reinforce the need to consider affective factors in our discussions and interventions for supporting math performance in college students.
Sivelestat's effect on Candida albicans water‐soluble fraction‐induced vasculitis
Authors: Yoshida Yuya , Banno‐Terada Rie , Takada Masashi , Fujii Toui , Takagaki Naofumi , Maekawa Aoi , Tanaka Arisa , Endo Miki , Yamada Ayaka , Mamiya Ryota , Nagi‐Miura Noriko , Ohno Naohito , Tsuji Takumi , Kohno Takeyuki
Published: January 2022

Background

We investigated the efficacy of sivelestat sodium hydrate (SSH) as a treatment for Kawasaki disease, and its pharmacological action sites, in mice with Candida albicans water‐soluble fraction‐induced vasculitis.

Methods

Sivelestat sodium hydrate was administered intraperitoneally to Candida albicans water‐soluble fraction‐induced vasculitis model mice to assess its efficacy in preventing the development of coronary artery lesions based on the degree of inflammatory cell infiltration in the aortic root and coronary arteries (vasculitis score). The pharmacological sites of action were investigated based on changes in neutrophil elastase (NE) and intercellular adhesion molecule 1 (ICAM‐1) positive areas, ICAM‐1 and tumor necrosis factor‐α mRNA expression levels in the upper heart, and the proportion of monocytes in the peripheral blood.

Results

The vasculitis score decreased below the lower limit of the 95% confidence interval of untreated mice in 69% of the SSH‐treated mice. The NE‐ and ICAM‐1‐positive regions, and the mRNA expression of ICAM‐1 and tumor necrosis factor‐α were lower in the SSH‐treated mice than in the untreated mice. The proportion of monocytes in the peripheral blood was higher in the SSH‐treated mice than in the untreated mice, whereas monocyte migration to inflammation areas was suppressed in the SSH‐treated mice.

Conclusions

Our results showed that SSH might prevent the development of coronary artery lesions and ameliorate disease activity. In addition to its NE‐inhibitory effect, SSH sites of action may also include monocytes.
Health visiting in England: The impact of the COVID‐19 pandemic
Authors: Morton Alison , Adams Cheryll
Published: January 2022

This focused review of evidence considers the impact of the pandemic in 2020 on families with children under 5 years in England, and the health visiting (HV) service that supports them. . Data were drawn from national surveys of health visitors (HVs) and parents, a freedom of information request of employers, published research, and national data. Framework analysis and triangulation, using the Key Elements of an effective HV service, were used to categorize the key findings. The findings from the review indicate that the impacts of the pandemic were wide‐ranging and disproportionately affected the most disadvantaged families, increasing demand for HV support. HVs’ ability to respond was compromised due to national policy decisions to partially stop the service and variations in local implementation including the redeployment of HVs, pre‐existing workforce capacity issues, and the effectiveness of innovations to identify and support vulnerable families. The pandemic exacerbated factors that can lead to poorer outcomes for families. Key learning from the pandemic response, including the need to prioritize the HV service, must be acted upon to reduce ongoing impacts now and ensure that the service is equipped for future emergencies.
Data‐driven storage operations: Cross‐commodity backtest and structured policies
Authors: Mandl Christian , Nadarajah Selvaprabu , Minner Stefan , Gavirneni Srinagesh
Published: January 2022

Storage assets are critical for physical trading of commodities under volatile prices. State‐of‐the‐art methods for managing storage facilities such as the reoptimization heuristic (RH), which are part of commercial software, approximate a Markov Decision Process (MDP) assuming full information regarding the state and the stochastic commodity price process and hence suffer from informational inconsistencies with observed price data and structural inconsistencies with the true optimal policy, which are both components of generalization error. Focusing on spot trades, we find via an extensive backtest that this error can lead to significantly suboptimal RH policies. We develop a forward‐looking data‐driven approach (DDA) to learn policies and reduce generalization error. This approach extends standard (backward‐looking) DDA in two ways: (i) It represents historical and estimated future profits as functions of features in the training objective, which typically includes only past profits; and (ii) it enforces structural properties of the optimal policy. To elaborate, DDA trains parameters of bang‐bang and base‐stock policies, respectively, using linear‐ and mixed‐integer programs, thereby extending known DDAs that parameterize decisions as functions of features without policy structure. We backtest the performance of RH and DDA on six major commodities, employing feature selection across data from Reuters, Bloomberg, and other public data sets. DDA can improve RH on real data, with policy structure needed to realize this improvement. Our research advances the state‐of‐the‐art for storage operations and can be extended beyond spot trading to handle generalization error when also including forward trades.
The contemporary guru field
Authors: Lucia Amanda
Published: January 2022

The guru field—to implement sociologist Pierre Bourdieu’s understanding of the concept of “field”—is a term signifying the symbolic sphere of influence, power, and sociality populated by “specialized agents”, that is, in this case: charismatic Hindu religious leaders and their movements. Compounded with the term “contemporary,” the title of this article suggests a distinctive religious field located in the near present, at once characterized by modernity, globalization, and technological developments, and also by the postcolonial and post‐Independence context of modern India. This article aims to assess the contours of that historical trajectory, beginning with Swami Vivekananda’s speeches at the World’s Parliament of Religions and continuing through the present day. The author also proposes possible futures for emerging scholarly directions in assessing this influential and expanding scholarly field.
Development of a 3D Computational Human Knee Joint Model
Authors: Gil Jorge , Li Guoan , Kanamori Akihiro , Woo Savio L.-Y.
Published: January 2022

Numerical modeling of the human knee joint has been pursued by various researchers [1,2]. Several knee joint models have been reported to simulate the kinematic and dynamic response of the knee joint to external loads, which to various degrees are representative of those found in the knee’s daily function. However, experimental validation of these models has been scarcely documented. Typical validation procedures should include a comparison of computational results from numerical simulations, to those from experimental tests performed on actual human joint specimens. The loading conditions must be carefully controlled and reproduced from one testing approach to another for acceptable comparison of the knee joint responses.
Mathematical Modeling of Bus Rollover Crashes
Authors: Sharma Vivek , Mohan Dinesh , Chawla Anoop
Published: January 2022

Buses are widely used for public transport in all countries. There are no crash worthiness standards for buses in India. The body makers fabricate the bus body on the truck chassis according to the specifications of the user with little consideration for safety of passengers. This work is an attempt to study the effect of roll-overs on the structure of a typical Indian bus using the Finite Element Method (FEM). Multibody-FEM systems software MADYMO was used with the objective of evaluating the current structure and exploring alternatives. The existing and the modified bus structures were analyzed for vertical falling velocities of 4 m/s, 6 m/s, 8 m/s and 10 m/s and load of 500 kg, 1000 kg, 1500 kg and 2000 kg per “ring” of the bus. The preliminary results show that there is scope for improvement in the existing bus structure. The stiffness of the bus structure can be increased by supporting the ceiling of the bus on pillars. This modification reduces intrusion into the bus but the force on the bus structure increases. To increase the crash worthiness of the bus structure substantially an internal double roof needs to be incorporated. This modification reduces intrusion as well as the force. This project indicates the possibility to improve crash characteristics of vehicles used in India and other Asian countries without expensive rollover tests. The computer simulation techniques used in this project can be integrated with the design process of the vehicles from very beginning.
Collagenase-Induced Degradation of Rat Tail Tendon
Authors: Hunter Shawn A. , Grood Edward S.
Published: January 2022

Tissue grafts are widely used in the repair of damaged tendons and ligaments. However, studies have shown that these grafts rapidly lose their strength shortly after implantation [1]. One possible mechanism for such behavior is the degradation of the extracellular matrix (ECM) due to the action of collagenase, a matrix metalloprotenase. Studies investigating the effects of water content and uniaxial tension on collagen degradation by bacterial collagenase have been performed in the rabbit model [2]. However, results obtained using bacterial collagenase cannot be extrapolated to mammalian collagenase due to their differences in activity. In addition, the limited availability of mammalian collagenase makes it difficult to use in the relatively large rabbit model. The purpose of this study was to replicate bacterial collagenase experiments [2] using rat tail tendons in order to determine the feasibility of using the smaller rat model to study the effects of mammalian collagenase on tendon degradation.
Polymethylmethacrylate as a Thermal Barrier for Protecting the Spinal Cord
Authors: Mocarski R. B. , Park C. K. , Allen M. J. , Yuan H. A.
Published: January 2022

Polymethylmethacrylate (PMMA) is used to reconstruct the spine after total corpectomy. Pre-polymerized PMMA was evaluated as a potential thermal barrier to protect the spinal cord from the high temperatures reached during the exothermic reaction of the curing PMMA. An experimental fixture was developed to conservatively model the in-vivo case. A single factor experiment with three levels of barrier thickness and three replicates of each level was completed. The three levels of barrier thickness were 0mm (no barrier), 5mm and 8mm. In the experiment 60 ml of PMMA were poured on top of the barrier. Temperatures were measured in two locations; at the center of the mass of the curing PMMA, and on the “spinal cord” side of the barrier. The temperatures measured for the “spinal cord” side were 60°C, 47°C, and 43°C, for the 0mm, 5mm and 8mm barriers respectively. A single factor ANOVA shows these results to be significant. (ANOVA test 99%, P = 0.000024). Temperatures at the center of the curing PMMA mass were consistent at 106.75°C (σ = 3.88), and show the experiment to be well controlled. From the temperature measurements, heat flow from the curing PMMA into the barrier material was calculated. Values for the thermal conductivity of the PMMA barrier were in agreement with those reported previously by Huiskes (1980). In the clinical setting, it should be possible to use a thin layer of pre-polymerized PMMA as a barrier to protect the spinal cord from thermal damage.
Effects of Rapid Curvature Changes on Flow Through Coronary Artery Models
Authors: Weydahl Erlend , Santamarina Aland , Moore James E.
Published: January 2022

The localized nature of atherosclerosis has led to extensive study of blood flow patterns and their possible involvement in atherogenesis. Vessel geometry has always been considered a primary factor in determining blood flow patterns. In the coronary arteries, the geometry varies dynamically due to myocardial contraction. The effects of physiologic axial (Moore et al., 1994) and lateral (Delfino et al., 1994) vessel movement on coronary blood flow patterns have been shown to be important in producing oscillations in wall shear stress. Those studies were limited to straight vessels that translated in one direction only. Previous studies of flow in curved tubes with time-varying curvature showed that large quasi-static wall shear rate amplitudes relative to the static case when the curvature change was 50% of the mean curvature (Santamarina et al., 1997). The largest variation in wall shear rate from the minimum curvature to the maximum curvature was 52%, and was found at the mid-wall location (halfway between the inner and outer wall of curvature along the circumference) for the highest mean curvature ratio studied (δ = 0.12). A comparison of the shear rate amplitudes found in a tube whose radius of curvature varies dynamically at 1 Hz to the variations noted in the quasi-static analysis revealed differences of less than 1%. Changes in the mean wall shear rate predicted with the dynamic analysis were less than 7%, relative to the wall shear rate at the static mean radius of curvature. It was concluded that, although the change in curvature creates a relatively large shear rate amplitude, the fact that the curvature varies dynamically at 1 Hz is not important in predicting wall shear rates.
Flow Patterns in an Intracranial Side Wall Aneurysm Model Using Particle Image Velocimetry
Authors: Lieber B. B. , Nikolaidis N. , Wakhloo A. K.
Published: January 2022

We investigated flow patterns in an intracranial side wall aneurysm model under pulsatile flow conditions using Particle Image Velocimetry (PIV). The hemodynamic parameters were representative for those in human vertebral arteries. Analysis of flow patterns show the formation of a vortex and shifting of its center inside the aneurysm during the pulse cycle. Higher than normal values of shear stress were recorded on the proximal and distal neck of the aneurysm during the systolic phase of the cycle. Maximum values were attained during peak systole. However, the stresses on the distal neck of the aneurysm were always higher than the those proximally.
Numerical Simulations of Endovascular Balloon Occlusion for Cerebral Aneurysms
Authors: Minoura Tetsuji , Sakai Nobuyuki , Tsutsumi Sadami
Published: January 2022

We investigated how hardness of the material inside a balloon used for endovascular occlusion to treat cerebral aneurysm. This study was motivated by the fact that the balloon occlusion employing HEMA (2-hydroxyl ethylmethacrylate) can lead to further growth of aneurysm in many cases. We showed distribution of stresses acting on the cerebral aneurysm wall by means of a dynamic finite element method (FEM). We used a 2-dimensional finite element model assuming the conventional type of cerebral aneurysm. Our simulation results indicated that the optimal Young’s modulus of the material inside the balloon is about 100 kPa, which is much lower than that of HEMA. We believe that our simulation method can be used for a specific patient condition and provide a proper value of the Young’s modulus of the inside material.
A Study of the Influence of Womersley Number on Flow in Curved Pipes
Authors: Dwyer Harry A. , Cheer Angela Y.
Published: January 2022

A numerical study has been carried of the influence of Wormersley number on the fluid flow in curved pipes at high Dean number. The investigation has covered the important flow regimes in blood vessels, and a detailed study of the flow physics has been carried out. At high Womersley number the favorable and adverse pressure gradients domainate the flow, while the low Womersley results approach steady flow results. Detailed results are obtained for wall shear and the flow pressure field.
A Mathematical Model of the Artery Focused on the Behavior of Smooth Muscles in Active State
Authors: Yamada H. , Shinoda T. , Tanaka E. , Yamamoto S.
Published: January 2022

Smooth muscles activation causes a large change of the artery in the mechanical properties and the deformation behavior. Thus, mathematical modeling of the artery both in passive and in active states is required to describe the mechanical behavior in various cases such as solid-fluid interactions under flow regulation and muscular tissues contraction.
Secondary Flow Augmentation in Intermittent Oscillatory Flow in Model Human Central Airways
Authors: Tanaka Gaku , Ogata Tomoko , Oka Kotaro , Tanishita Kazuo
Published: January 2022

Axial and secondary velocity profiles through a model human central airways were measured to clarify the intermittent oscillatory flow structure during high-frequency oscillation. Velocities in the two directions were measured by a two-color laser-doppler velocimeter. In the trachea, secondary flow is enlarged at the early stationary phase in both the inspiratory and expiratory phases. This augmentation of secondary flow promotes axial gas dispersion by enhancing cross-stream mixing.
Effect of Different Geometric Parameters on the Flow Characteristics in a Symmetric Bifurcation Model
Authors: Farag Ashraf , Ng Terry , Olson Dan , Hammersley Jeffrey
Published: January 2022

Steady divergent flow (inspiratory directed) is measured using Laser Doppler Velocimetry in large scale models carefully mimicing the morphometry of small human airways. We Evaluated the anatomical features which induced vorticity in the flow from a vorticity free entrance, under conditions of convective similitude (simultaneous Reynolds And Dean’s Numbers). Five symmetrical bifurcation models with different bifurcation angles and curvature ratios are tested. A flow separation (carina) in each model is shaped to anatomical measures and the conformation of the transition between parent and daughter branches representing the morphmetric mean shape defined from casts of human airways. The flow pattern in the daughter tubes is typical of laminar flow within the entrance (diameter/axial length < 5) to sharp bends (Dean number > 500), with rapid development of strong secondary flows (maximum secondary velocity is 40% of mean axial velocity) consisting of two main vortices, with two smaller and weaker secondary vortex activities towards the inner wall of curvature. These may be time dependent interrelation with these vortices causing warbling at specific flow conditions. The calculated vorticity transport along the flow axis showed interaction between the viscous forces at the new boundary layer development along the carinal wall and centrifugal forces of curvature, with a significant influence by the upstream flow prior to the entering the actual flow division. This interplay resulted in an overshoot of the calculated vorticity transport comparable to flow entering curved bends an a suppression for the tendency to separate at the inner wall of these tight bends. The maximum primary flow velocities are skewed towards the carinal side (outer wall of curvature) and development of a second peak occurred with convection of the higher velocity elements towards the inner wall of curvature by the strong secondary flow. The appearance of the second peak depends mainly on the curvature ratio of the daughter tubes. This study is the “baseline” observation for a airway structure to function analysis. The observed flow patterns have high influence on conductive mixing, particle deposition, volume flow distribution, gaseous scrubbing (absorption at the liquid wall surfaces), and conductive-diffusive axial dispersion mechanism; all critical features for respiration.

Detailed velocity measurements are carried out in all models at different axial locations. The locations are chosen according to the expected rate of velocity alterations in the models. Figures 1 to 4 show some typical primary and secondary velocities in models 1 (1/7 curvature ration and 70° bifurcation angle) and 4 (1/14 curvature ratio and 70° bifurcation angle at Reynolds number of 1500 based on the parent tube diameter. As can be seen in Figures 1 and 2, the second peak is not observed in model 4 while it is clearly observed in model 1.
Computational Visualization of External and Internal Biological Flows With Fluid-Wall Interactions
Authors: Yamaguchi Takami , Liu Hao
Published: January 2022

Most of biologically interesting flows consist of four dimensional (4D), i.e. of three spatial and one temporary dimensions, motion. This is always true regardless it is the internal or the external biological flow field. In the blood flow, one of representative internal flows, the blood vessel has extremely complex 3D configuration and the flow is highly unsteady due to an oscillatory driving pressure generated by the heart. Respiratory flow, which is another important internal flow in the living animals, is a purely oscillatory flow with null mean in time. The airway is also as complex as the vascular system in its configuration and constitution. External flow phenomena are not exceptions to this. Flows passing over wings of flying animals and fins of swimming animals are also strongly unsteady due to oscillatory motion of these propelling structures. The shape of wings and fins is far from simple and their motion is complex in the spatial three dimensions.
Dynamic Response of Vehicles and Occupants During Full-Scale Sideswipe Crash Tests
Authors: Khadilkar Anil V. , Laviano Claude , Ward Parris , Hoffman Michelle , Shyer Bruce N.
Published: January 2022

Many vehicle crashes involve sideswipes. In 1994, NHTSA’s data collected from FARS and GES files showed that sideswipes accounted for 4.6 percent of the total number of motor vehicle accidents. Sideswipe crashes occur at both freeway/highway speeds and at city street speeds and are characterized by one vehicle effectively running along the side of another vehicle. Typically, sideswipes result in vehicle damage with limited penetration; however, the length of damage along the side of the vehicle can be extensive and can result in high damage repair costs. Limited technical literature is available regarding sideswipe crashes, specifically that involving the use of instrumented volunteer occupants. This paper presents details and the results from a sideswipe test conducted by the authors in December, 1997. The test was conducted to recreate an actual sideswipe vehicle crash that was a part of a litigation case the authors were involved in.
Occupant Motion Modeling in Rollover Accidents: Effects of Ellipsoid Surface Contact Characteristic Variations
Authors: Renfroe David A. , Partain Joe F.
Published: January 2022

In order to facilitate the design of safer occupant vehicle environments a method has been demonstrated whereby occupants in a rollover collision may be modeled. The modeling technique has previously been demonstrated (Renfroe, et.al., 1998). This publication reviews the previous work and illustrates how the stiffness, damping, hysterisis, and coefficient of friction describing each ellipsoid contact representing the vehicle striking the road does not have to be precisely the measured stiffness characteristics.
Computer Simulations of Human Neck Loads in a Car Equipped With an Airbag
Authors: Luan Feng , Zhao Longmao , Yang King H.
Published: January 2022

It has been shown that driver fatalities in frontal collisions were reduced by 28% in airbag-equipped cars based on comparisons with similar cars equipped with manual lap/shoulder belts only (Zador and Ciccone, 1991). A similar finding was reported by the Department of Transportation that driver fatality rates in airbag equipped cars were reduced by 31% in purely frontal crashes (12:00 point of impact on the vehicle), and 19% in all frontal crashes (10:00 to 2:00). About 10% of drivers of vehicles with airbags involved in accidents received moderate to severe injuries. Most, if not all, of these people would have been more seriously injured or killed without the airbag. In a recent report to Congress, NHTSA estimated that airbags have saved 1,198 lives from 1987 through 1995, including 475 lives saved in 1995 alone.
Stability of the Lumbar Spine Subjected to a Follower Load: Part II — Theoretical Results
Authors: Meade Kevin P. , Patwardhan Avinash G.
Published: January 2022

A number of theoretical studies of the stability of structures subjected to follower loads have been reported in the literature. The classic example is due to Beck who, in 1952, investigated the stability of a cantilevered beam-column subjected to a load applied to its free end that remained exactly tangent to the deflection curve (Atanackovic, 1997 and Timoshenko, 1961). To obtain the critical load it was necessary to perform a dynamic analysis of the problem. In problems such as these, instability comes in the form of flutter rather than divergence.

The purpose of this study was to assess the stability of the lumbar spine under loading conditions similar to those in Patwardhan, et al., 1998. In their experiments, a follower load was applied to the lumbar spine using guided cables that remained tangent to the deformed shape of the lumbar curve. In this study we adopted a model similar to Crisco and Panjabi (1992a) but with important differences.

Crisco and Panjabi (1992a) investigated the Euler stability of the lumbar spine using a lumped parameter model consisting of five (rigid) vertebral bodies connected by pin joints and torsional springs. The loading was applied vertically at L1. The model predicted buckling loads similar to the ones reported by Lucas and Bresler (1961). Both the predicted and the measured buckling loads of Crisco and Panjabi (1992a,b) are far below the load levels seen in vivo.

In our model, the loads were applied at each joint instead of at L1 only. Also, the direction of the applied loads depended upon the deformation. The direction of the load at one joint was proportional to the angular displacement of the segment below it. That is, the loads did not exactly follow the direction of the tangent to the deformed curve. This allowed us to assess the stability of the model spine when it was subjected to an “imperfect” follower load. An interesting feature of the problem was that it required only a static analysis.

The results of the study demonstrated the sensitivity of the buckling load to the “misalignment” of the follower path. As the direction of the loads approach the follower path, the buckling load increases beyond the Euler critical load. This was not an unexpected result. The increased buckling load predicted in this analysis was consistent with the experimental observations of Patwardhan, et al. (1998).

However, there was a surprising result. The analysis showed that there is a mechanism for a smooth transition between the buckled shapes which is not seen in the classical Euler analysis (Timoshenko, 1961).

These results may have implications for how imperfections in muscle coactivation can affect the stability of the lumbar spine. Also, they may help explain some of the phenomena seen in progression of diseases of the spine such as scoliosis.
In Vitro Quasi-Static and Cyclic Biomechanics of a Cervical Spine Posterior Plate Versus Facet Wiring in a Laminectomy Model
Authors: Scifert Jeffrey L. , Goel Vijay K. , Smith Darin W. , Traynelis Vincent C.
Published: January 2022

Stability comparisons of cervical facet wiring and posterior cervical plating in a quasi-static and cyclic environment contain important clinical ramifications and this research addresses this issue. Decreases in motion at C4-C5 after undergoing bilateral laminectomy and subsequent stabilization indicated that plate decreases in motion were markedly higher than facet wiring decreases in all cases except cyclic extension. Posterior plates were superior in almost every loading mode tested, including the cyclic mode. The stabilized and cyclic results were only similar in extension between plates and wires. Screw torque decreases between pre- and post-fatigue plate measurements did not appear to affect specimen stability. Posterior plates appear to be biomechanically superior to facet wiring in cervical spine stabilization following laminectomy.
Temperature-Dependent Viscoelastic Properties of the Supraspinatus Tendon
Authors: Huang Chun-Yuh , Wang Vincent M. , Roh Michael S. , Pawluk Robert J. , Flatow Evan L. , Mow Van C.
Published: January 2022

The relevance of studying the temperature-dependence of ligament and tendon mechanical properties has been well documented [4,8,12,15]. While investigations of tendon and ligament mechanics are typically performed at controlled in-vitro temperatures (e.g., room temperature), these conditions clearly are different from those in vivo. Results from the various investigations have not been consistent. For instance. Rigby et al. [12] found no significant differences in the mechanical properties of rat tail tendon between 0°C and 37°C, while Woo and coworkers [15] reported significantly increased cyclic load relaxation and decreased tensile load with increasing temperature from 2°C to 37°C. A more recent study by Lam et al. [8] showed that in rabbit ligaments the temperature effects are minimal in shorter duration tension tests (i.e., more elastic-dominated) but readily apparent in a more viscous-dominated test such as creep or stress relaxation.
Application of a Special Theory of Biphasic Mixtures to Annulus Fibrosus
Authors: Klisch Stephen M. , Lotz Jeffrey C.
Published: January 2022

We applied a special theory of an incompressible mixture of an elastic solid and an inviscid fluid to experimental data (Iatridis et al., 1995) for axial confined compression of annulus fibrosus in finite deformation. We found that this special theory demands a significantly different nonlinear permeability function than the widely used theory of Kwan et al. (1990) and Holmes and Mow (1990) to achieve a best-fit regression to the surface stress time history.
Wear of Retrieved CoCrMo Articulating Surfaces in Total Hip Arthroplasty
Authors: Scott Marcus L. , Eberhardt Alan W. , Lemons Jack E.
Published: January 2022

Wear particle-induced osteolysis is widely regarded as the leading long-term complication associated with total hip arthroplasty (THA) [1]. The need to reduce or eliminate UHMWPE debris has led to renewed interest in alternatives to the current metal-UHMWPE bearing couple, including a reevaluation of metal-on-metal designs. Previous analyses of both simulator-tested and retrieved metal-on-metal THA articulating components have shown that wear rates tend to decrease with a longer time in situ [2,3]. This phenomenon may result from an initial period of accelerated “run-in” wear, in which there is a partial removal of surface asperities and a correction of implant asphericity. This may lead to enhanced fluid film lubrication at the articulation interface and ultimately reduce long-term wear rates of the bearing components. The objectives of this study were to quantify the wear rates of a series of explanted Sivash metal-on-metal bearing components and to characterize changes in surface geometry configurations in order to better understand the running-in phenomenon associated with metal-on-metal bearing surfaces.
Biomechanics of Vestibular Hair Cell Bundles
Authors: Cotton John R. , Grant J. Wallace
Published: January 2022

Hair cells are transducers present in the inner-ear of vertebrates. They convert a mechanical signal into a neurochemical one and are the first cellular component of both vestibular and auditory systems. The mechanical sensor of the hair cell is the ciliary bundle which projects into an extracellular space where it receives an external force either by fluid flow or the displacement of a nearby structure to which the bundle is attached.
A Child’s Hand With Self-Energizing Grasp
Authors: Landsberger Samuel , Shaperman Julie , Lin Andrew , Vargas Vicente , Fite Richard , Setoguchi Yoshio , McNeal Donald
Published: January 2022

Parents of children with upper-extremity limb deficiencies, and clinicians, have long expressed the need for a better body-powered hand. Our objective is to develop an improved hand and activation system for toddlers between the ages of one and four. The primary design goals are: (i) acceptable cosmesis (hand-like appearance), (ii) useful grasp function for play activities, and (iii) minimal requirements for harness force and motion inputs from the child.

The approach has been to explore several hand design strategies in parallel with different methods of harnessing the child’s considerable energies and, where these fall short, provide robust means of amplifying the child’s energy output.

A simple hand called “Easy Feed” shows promise in both grasp capability and suitability to a toddler’s cognitive and physical development. We are investigating coverings for the structure alongside design of the hand’s mechanical linkage. Force and Power augmentation modules in development will assist children with less strength.
The Effect of Cement Thickness & Surface Roughness on the Strength of the Metal-Cement Interface
Authors: Gruen Thomas A. , Shockley Darryl , Norman Timothy L.
Published: January 2022

Acrylic bone cement is commonly used to affix metallic femoral hip implants within the proximal femur during hip arthroplasty. Previous studies indicate that the expected life of a cemented implant may depend on the integrity of the metal-cement interface and that the interface strength can be influenced by many factors such as variable cement technique, surface roughness of the metal implant, or using pre-coated implants. To this date, there is no study, as far as is known, on the effect of cement thickness on the integrity of the metal-cement interface. The purpose of this study was to determine whether different cement mantle thickness affected the mechanical integrity of the metal-cement interface. Two different surface roughness of commercially manufactured Co-Cr cylindrical implants were cemented into plastic cylindrical molds simulating the femoral intramedullary cavity. Post-cured specimens were evaluated under four test conditions including 24-hours stored dry at room temperature (rt), 3-months dry (rt) storage, and 3-months immersion in physiological saline solution (rt) or at body temperature (bt). Parametric analysis of the metal-cement interface, measured with the push-out test method, indicated that all grit-blasted implants regardless of cement thickness and test conditions had mean interface strength values of approximately 5 MPa. With the polished implants and thick cement mantle (i.e. 6.3 mm) the mean interface strength was an order of magnitude lower, i.e. ≈ 0.5 MPa, and was significantly reduced after 30 days of immersion. For the polished implants with thin cement mantle (i.e. 2.4 mm) the mean interface strength values were approximately 0.1 MPa for all test conditions. In summary, in this study the metal-cement interface bond was maintained with grit-blasted surfaced implants under the different test conditions; however, debonding of polished surfaced implants with thick cement mantle was sensitive to test conditions and that debonding was readily obtained with the thin cement mantle. It is concluded that thin cement mantles around metallic femoral stems may result in earlier debonding at the metal-cement interface thereby increasing the risk of early failure of a cemented implant system with cylindrical stems.
Wear-Resistant Properties of Newly 3-D Orientated UHMWPE for Artificial Joints
Authors: Ohta Makoto , Hyon Suong-Hyu , Oka Masanori , Tsutsumi Sadami
Published: January 2022

UHMWPE was crystallized under molecular orientation in order to improve the wear resistant properties against Co-Cr-Mo alloys, since these two materials are used for artificial joints. We measured weight loss of UHMPWE by using a pin-on-flat reciprocating type wear machine. It was confirmed that, when the sample was compressed in the molten state, wear resistant properties of UHMWPE increased greatly with increasing degree of compression.
An EMG-Driven Musculoskeletal Model for Estimation of Human Joint Moments During Isometric Time-Varying Loads
Authors: Buchanan Thomas S. , Cheng Jian-Yu , Shen Xiaofeng , Manal Kurt
Published: January 2022

The purpose of this work was to develop a robust EMG-driven elbow model to estimate muscle forces and joint torques of different people performing different time-varying loads at the elbow. The model consisted of an anatomical model, an EMG-to-activation model, a Hill-type muscle model, and a nonlinear optimizer. All of the major muscles about the elbow were taken into account. The parameters used by the muscle model were optimal fiber length, maximum contraction velocity, pennation angle, tendon slack length, and maximum muscle force. EMG and joint angle were input variables. Moment arm and muscle length varied as a function of joint angle, as defined in the anatomical model. The model was used to examine the importance of accounting for muscle velocity during rapid loads applied at fixed joint angles.
Reoxygenation in Tumor Tissues After X-Ray or Carbon-12 Irradiation
Authors: Fukawa Takeshi , Takematsu Koji , Oka Kotaro , Miyahara Nobuyuki , Koike Sachiko , Ando Koichi , Kobayashi Hirosuke , Tanishita Kazuo
Published: January 2022

We measured directly the partial pressure of oxygen (pO2) in new fibrosarcoma (NFSa) tumors grown in C3H/He mice using microcoaxial O2 electrodes in vivo. The pO2 in tumors was monitored after a single dose of X-ray or carbon-12 irradiation. After irradiation, tumor volume temporally shrinked, and pO2 simultaneously increased. Carbon-12 irradiation reoxygenated tumors between the 1st and 9th day after the irradiation, while x-ray irradiation reoxygenated tumors between the 3rd and 8th day. We found that reoxygenation period after carbon-12 irradiation started earlier and continued longer than X-ray irradiation.
Scientific Characterization of the Rincoe Socket and Tekscan F-Socket Interface Pressure Measurement Systems: Implications for Clinical Utility
Authors: Polliack Adrian A. , Landsberger Samuel , McNeal Donald R. , Craig Dana , Sieh Robert , Ayyappa Edmund
Published: January 2022

Socket fabrication is a highly refined art that relies on the skill and experience of the prosthetist. Despite best efforts, patients often return to the prosthetist with complaints of residual limb pain, socket discomfort and skin problems. To prevent problems such as these and resolve problems that have developed, the prosthetist relies primarily on verbal feedback from the patient and visual inspection of the residual limb. Clinical techniques for the quantification of biomechanical factors at the socket interface are not in common use. Specifically, the two commercially available interface pressure measurement systems, the Rincoe Socket Sensor and the Tekscan F-Socket Measurement Systems, are not employed by many prosthetists. This is perhaps due to cost, difficulty in clinical interpretation of the data, and time required for operation.1 Furthermore, these systems have not undergone any scientific evaluation for validity.
Mechanical Model for Myocardial Trabeculation
Authors: Taber Larry A.
Published: January 2022

Trabeculation of the embryonic heart is studied using a biomechanical model for epithelial morphogenesis. The analysis of the model includes large deformation and cytoskeletal activation. Illustrative results for a membrane on an elastic foundation (substrate) illustrate the pattern-forming capability of the model, with concentrations in membrane thickness representing trabeculae.
Prediction of Glide Avalanche Based on Composite Roughness
Authors: Suzuki Shoji
Published: January 2022

Surface topography of a magnetic disk is one of the key parameters to determine safe fly height in a hard disk drive. In order to quantify the flying capability of the disk surface, glide avalanche is a useful parameter because it is the parameter which indicates the height of the surface topography from the mean surface below which a head can not fly without contacts. The avalanche is regarded as the floor of the disk surface intrinsically defined by the surface finish during disk production. The glide height is set at higher level than the avalanche and usually limited by isolated defects or contamination on the surface. Because of this direct couple between glide avalanche and the disk surface finish, the measurement and prediction of the glide avalanche are very important. In this paper, we discuss the importance of fly height characterization of a glide head and the relationship between disk surface topography and its avalanche. We propose a simple yet versatile model based on a composite roughness, which can be applied to a polished surface and to a textured contact start/stop zone including laser bumps.
Natural Frequency Analysis of PZT Glide Heads During Contact
Authors: Tsay Alex Y. , Ku C.-P. Roger , Shen I. Y. Steve , Marchon Bruno
Published: January 2022

The natural frequencies (NFs) and the corresponding mode shapes of a glide head with a piezoelectric transducer (PZT) mounted on its extended wing have been studied both analytically and experimentally. Finite element analysis results indicate that the extended wing reduces the NFs of the glide head substantially. The manufacturing tolerances of the slider and PZT as well as the PZT bonding location can have a significant effect on the NFs. As the glide head contacts the laser bump texture during the landing process, the NFs of the glide head increase slightly, probably because of the constraint provided by the stiffness of the bumps during the contact. The NFs calculated by finite element analysis show good agreement with the data obtained using two different experimental methods.
Mixed Finite Element Solution for a Magnetostatic Inverse Problem
Authors: Shigeta Takemi
Published: January 2022

The purpose of this paper is to present a numerical method of solution for a two-dimensional magnetostatic problem. The normal component of the magnetic flux density and the tangential component of the magnetic field with errors are simultaneously imposed on a part of the boundary of a bounded domain of the problem. The problem can be regarded as a boundary value inverse problem, because the proper boundary condition is to be identified for the rest of the boundary. The treatment is based on the method of least squares, and the steepest descent method minimizes an objective functional with a regularization term. The direct variational method paraphrases the inverse problem to the primary and the adjoint boundary value problems. The mixed finite element method using the edge element and the conventional finite element method are applied to the numerical solutions of the boundary value problems. Based on numerical computations, it is concluded that an estimated solution for the boundary data without errors is in agreement with an exact one, and the regularization term yields good approximate solutions for the boundary data with errors.