bluuebunny/crossref_metadata_2025 huggingface dataset:
Machine learning‐based decision tree classifier for the diagnosis of progressive supranuclear palsy and corticobasal degeneration
Authors: Koga Shunsuke , Zhou Xiaolai , Dickson Dennis W.
Published: March 2021

Aims

This study aimed to clarify the different topographical distribution of tau pathology between progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) and establish a machine learning‐based decision tree classifier.

Methods

Paraffin‐embedded sections of the temporal cortex, motor cortex, caudate nucleus, globus pallidus, subthalamic nucleus, substantia nigra, red nucleus, and midbrain tectum from 1020 PSP and 199 CBD cases were assessed by phospho‐tau immunohistochemistry. The severity of tau lesions (i.e., neurofibrillary tangle, coiled body, tufted astrocyte or astrocytic plaque, and tau threads) was semi‐quantitatively scored in each region. Hierarchical cluster analysis was performed using tau pathology scores. A decision tree classifier was made with tau pathology scores using 914 cases. Cross‐validation was done using 305 cases. An additional ten cases were used for a validation study.

Results

Cluster analysis displayed two distinct clusters; the first cluster included only CBD, and the other cluster included all PSP and six CBD cases. We built a decision tree, which used only seven decision nodes. The scores of tau threads in the caudate nucleus were the most decisive factor for predicting CBD. In a cross‐validation, 302 out of 305 cases were correctly diagnosed. In the pilot validation study, three investigators made a correct diagnosis in all cases using the decision tree.

Conclusion

Regardless of the morphology of astrocytic tau lesions, semi‐quantitative tau pathology scores in select brain regions are sufficient to distinguish PSP and CBD. The decision tree simplifies neuropathologic differential diagnosis of PSP and CBD.
Attribution and projections of temperature extreme trends in South America based on CMIP5 models
Authors: Rusticucci Matilde , Zazulie Natalia
Published: March 2021

Temperature extreme indices were analyzed for five continental regions of southern South America defined according to their climatic characteristics. Gridded observations, reanalysis, and global‐coupled climate models from CMIP5 were used with the approach of temperature extreme trend attribution analysis on fixed‐threshold and percentile‐based temperature extremes indices defined by the Expert Team on Climate Change Detection and Indices (ETCCDI). The largest positive trends are exhibited in the tropical nights index, and a clear anthropogenic signal is evident in the subtropical region. In the subtropical central Andes, there is a decrease in the frost days index and increases in the tropical nights and summer days indices, and an anthropogenic signal is evident. In the Patagonian region, all trends from the historical runs were significant, while the ones from the natural experiment were nonsignificant, showing the marked effect of anthropogenic forcing in this region in the extreme temperature events. Projected changes in extreme indices for the 21st century are consistent with a warming climate, and larger changes are expected in the warm nights index.
The commonness of rarity in a deep‐sea taxon
Authors: McClain Craig R.
Published: March 2021

The generality and drivers of rarity, defined along the axes of geographic range, population size and habitat specificity, have received considerable scientific attention for well over a century. Yet, studies that examine rarity holistically among these three attributes are limited, especially among invertebrate and marine taxa. The perceived paradox of deep‐sea species, with often low population size but large geographic ranges, remains poorly resolved and understood. Here I assess seven forms of rarity and their drivers in deep‐sea bivalves across the Atlantic Ocean. Rarity appears to be a common trait among deep‐sea bivalves, with nearly 85% of the species exhibiting some form of rarity. Bivalves also showed a strong bimodal pattern of very common and very rare species. Geographic range, population size and habitat specificity were all heavily right skewed. Taxonomic superfamilies, body size, energy availability, temperature, depth and latitude, all significantly predicted geographic range, population size and habitat specificity. In a few cases, these patterns were counter to theoretical expectations. The drivers of rarity appear to be predictable from knowledge of the intrinsic biological and extrinsic environmental context of the species. These findings have major implications for deep‐sea conversation, especially as anthropogenic threats are increasing.
A sugarcane mosaic virus vector for rapid in planta screening of proteins that inhibit the growth of insect herbivores
Authors: Chung Seung Ho , Bigham Mahdiyeh , Lappe Ryan R. , Chan Barry , Nagalakshmi Ugrappa , Whitham Steven A. , Dinesh‐Kumar Savithramma P. , Jander Georg
Published: March 2021

Spodoptera frugiperda (fall armyworm) is a notorious pest that threatens maize production worldwide. Current control measures involve the use of chemical insecticides and transgenic maize expressing Bacillus thuringiensis (Bt) toxins. Although additional transgenes have confirmed insecticidal activity, limited research has been conducted in maize, at least partially due to the technical difficulty of maize transformation. Here, we describe implementation of a sugarcane mosaic virus (SCMV) vector for rapidly testing the efficacy of both endogenous maize genes and heterologous genes from other organisms for the control of S. frugiperda in maize. Four categories of proteins were tested using the SCMV vector: (i) maize defence signalling proteins: peptide elicitors (Pep1 and Pep3) and jasmonate acid conjugating enzymes (JAR1a and JAR1b); (ii) maize defensive proteins: the previously identified ribosome‐inactivating protein (RIP2) and maize proteinase inhibitor (MPI), and two proteins with predicted but unconfirmed anti‐insect activities, an antimicrobial peptide (AMP) and a lectin (JAC1); (iii) lectins from other plant species: Allium cepa agglutinin (ACA) and Galanthus nivalis agglutinin (GNA); and (iv) scorpion and spider toxins: peptides from Urodacus yaschenkoi (UyCT3 and UyCT5) and Hadronyche versuta (Hvt). In most cases, S. frugiperda larval growth was reduced by transient SCMV‐mediated overexpression of genes encoding these proteins. Additionally, experiments with a subset of the SCMV‐expressed genes showed effectiveness against two aphid species, Rhopalosiphum maidis (corn leaf aphid) and Myzus persicae (green peach aphid). Together, these results demonstrate that SCMV vectors are a rapid screening method for testing the efficacy and insecticidal activity of candidate genes in maize.
Facultative symbiosis with a saprotrophic soil fungus promotes potassium uptake in American sweetgum trees
Authors: Peng Long , Shan Xiaoliang , Yang Yuzhan , Wang Yuchen , Druzhinina Irina S. , Pan Xueyu , Jin Wei , He Xinghua , Wang Xinyu , Zhang Xiaoguo , Martin Francis M. , Yuan Zhilin
Published: March 2021

Several species of soil free‐living saprotrophs can sometimes establish biotrophic symbiosis with plants, but the basic biology of this association remains largely unknown. Here, we investigate the symbiotic interaction between a common soil saprotroph, Clitopilus hobsonii (Agaricomycetes), and the American sweetgum (Liquidambar styraciflua). The colonized root cortical cells were found to contain numerous microsclerotia‐like structures. Fungal colonization led to increased plant growth and facilitated potassium uptake, particularly under potassium limitation (0.05 mM K+). The expression of plant genes related to potassium uptake was not altered by the symbiosis, but colonized roots contained the transcripts of three fungal genes with homology to K+ transporters (ACU and HAK) and channel (SKC). Heterologously expressed ChACU and ChSKC restored the growth of a yeast K+‐uptake‐defective mutant. Upregulation of ChACU transcript under low K+ conditions (0 and 0.05 mM K+) compared to control (5 mM K+) was demonstrated in planta and in vitro. Colonized plants displayed a larger accumulation of soluble sugars under 0.05 mM K+ than non‐colonized plants. The present study suggests reciprocal benefits of this novel tree‐fungus symbiosis under potassium limitation mainly through an exchange of additional carbon and potassium between both partners.
Chlororustica gen. nov. for the coccoid, zoospore‐producing alga Neochloris terrestris (Sphaeropleales, Chlorophyceae)
Authors: Watanabe Shin , Mezaki Naoto , Suzuki Tatsuya
Published: March 2021

Neochloris terrestris possesses ultrastructural features distinct from those of other species of Neochloris sensu stricto belonging to the Neochloridaceae. However, it was not classified properly due to the absence of phylogenetic information. We used an analysis of 18S rDNA sequence data as well as newly obtained ultrastructural data to support placement of this taxon in Chlororustica gen. nov. as C. terrestris comb. nov. in the Radiococcaceae.
Principal Manifold Estimation Via Model Complexity Selection
Authors: Meng Kun , Eloyan Ani
Published: March 2021

We propose a framework of principal manifolds to model high-dimensional data. This framework is based on Sobolev spaces and designed to model data of any intrinsic dimension. It includes principal component analysis and principal curve algorithm as special cases. We propose a novel method for model complexity selection to avoid overfitting, eliminate the effects of outliers and improve the computation speed. Additionally, we propose a method for identifying the interiors of circle-like curves and cylinder/ball-like surfaces. The proposed approach is compared to existing methods by simulations and applied to estimate tumour surfaces and interiors in a lung cancer study.
Neo‐Endogenous Rural Development: A Path Toward Reviving Rural Europe*
Authors: Georgios Chatzichristos , Nikolaos Nagopoulos , Michalis Poulimas
Published: March 2021

The 2008 fiscal crisis, inflamed by austerity measures, has prompted rural marginalization and societal segmentation across the European Union (EU). The current article investigates how a European rural revival can be materialized, without losing sight of the national and local conditions. Within the contemporary EU governance framework—in which a European institution cannot be categorized as endogenous or exogenous to a sub‐state nation—the concept of neo‐endogenous rural development seems more topical than ever. The term describes a new perspective of governance that reconciles the endogenous to the exogenous dynamics. Along these lines, the present article dwells on the question of how can the neo‐endogenous rural development agenda be disseminated across the EU. By identifying the lack of international comparative research in the field of rural development, the current study explores different European, rural development trajectories and draws meaningful comparisons. A comparative qualitative research was conducted in three rural regions, stratified in terms of economic and governance decentralization: Mühlviertel in Austria, Baixo Alentejo in Portugal, and Phthiotis in Greece. The comparative research indicated the importance of interregional networking and socially innovative governance for the embeddedness of a neo‐endogenous rural development agenda.
What Matters to You Matters: Natural Mentors and Self‐valuation in School Sports
Authors: Kelley Margaret S. , Lune Howard , Vaggalis Kathryn
Published: March 2021

Mentors for adolescents are widely believed to improve life chances and reduce problem behavior. Using 42 retrospective qualitative interviews with undergraduate former high school athletes and social learning theory as a framework, we investigate what it means to adolescents to matter to their school‐based natural mentors. Findings indicate that natural mentors represent a fundamental social connection that helped participants feel like they mattered. We identify three structural domains of social identity in which mattering operates: relationship, gender, and athletic. Natural mentoring led to connecting with non‐kin, feeling important, and creating accountability to significant others. Mentorship and mattering were deeply gendered; in reinforcing attributes of athletic success and physical or mental growth, mentor relationships both contributed to and helped subvert the structure of traditional gender roles and provide insight into the ways men and women navigate the contested and gendered space of sport. Finally, these mentoring relationships demonstrated the intersectional nature of sport and its physicality by linking the body and soul. Mattering is the mechanism for social learning that facilitates these crucial relationships. The implications of these findings are discussed, along with suggestions for future research.
How Can Biomechanical Multibody Models of Scoliosis Be Accurate in Simulating Spine Movement Behavior While Neglecting the Changes of Spinal Length?
Authors: Jalalian Athena , Arastehfar Soheil , Gibson Ian , Tay Francis E. H. , Liu Gabriel
Published: March 2021

This paper studies how biomechanical multibody models of scoliosis can neglect the changes of spinal length and yet be accurate in reconstructing spinal columns. As these models with fixed length comprise rigid links interconnected by rotary joints, they resemble polygonal chains that approximate spine curves with a finite number of line segments. In mathematics, using more segments with shorter lengths can result in more accurate curve approximations. This raises the question of whether more accurate spine curve approximations by increasing the number of links/joints can yield more accurate spinal column reconstructions. For this, the accuracy of spine curve approximation was improved consistently by increasing the number of links/joints, and its effects on the accuracy of spinal column reconstruction were assessed. Positive correlation was found between the accuracy of spine reconstruction and curve approximation. It was shown that while increasing the accuracy of curve approximations, the representation of scoliosis concavity and its side-to-side deviations were improved. Moreover, reconstruction errors of the spine regions separated by the inflection vertebrae had minimal impacts on each other. Overall, multibody scoliosis models with fixed spinal lengths can benefit from the extra rotational joints that contribute toward the accuracy of spine curve approximation. The outcome of this study leads to concurrent accuracy improvement and simplification of multibody models; joint-link configurations can be independently defined for the regions separated by the inflection vertebrae, enabling local optimization of the models for higher accuracy without unnecessary added complexity to the whole model.
Biomechanics of Single Stair Climb With Implications for Inverted Pendulum Modeling
Authors: Buffinton Christine Miller , Blaho Roberta K. , Bieryla Kathleen A.
Published: March 2021

Step-by-step (SBS) stair navigation is used by those with movement limitations or lower-limb prosthetics and by humanoid robots. Knowledge of biomechanical parameters for SBS gait, however, is limited. Inverted pendulum (IP) models used to assess dynamic stability have not been applied to SBS gait. This study examined the ability of the linear inverted pendulum (LIP) model and a closed-form, variable-height inverted pendulum (VHIP) model to predict capture-point (CP) stability in healthy adults executing a single stair climb. A second goal was to provide baseline kinematic and kinetic data for SBS gait. Twenty young adults executed a single step onto stairs of two heights, while attached marker positions and ground reaction forces were recorded. opensim software determined body kinematics and joint kinetics. Trials were analyzed with LIP and VHIP models, and the predicted CP compared to the actual center-of-pressure (CoP) on the stair. Lower-limb joint moments were larger than those reported for step-over-step (SOS) stair gait. Leading knee rather than trailing ankle was dominant. Center-of-mass (CoM) velocity peaked at push-off. The VHIP model accounted for only slightly more than half of the forward progression of the vertical projection of the CoM and was not better than LIP predictions. This suggests that IP models are limited in modeling SBS gait, likely due to large hip and knee moments. The results from this study may also provide target values and strategies to aid design of lower-limb prostheses and powered exoskeletons.
Influence of Impeller Sinusoidal Tubercle Trailing-Edge on Pressure Pulsation in a Centrifugal Pump at Nominal Flow Rate
Authors: Lin Yanpi , Li Xiaojun , Li Bowen , Jia Xiaoqi , Zhu Zuchao
Published: March 2021

The high-speed rotation of impellers leads to strong rotor–stator interaction, which mainly causes the pressure pulsation of centrifugal pumps. An impeller with a bionic sinusoidal tubercle trailing edge (STTE) can reduce the intensity of the rotor–stator interaction and thus reduce the pressure pulsation of the centrifugal pump. In this study, three profiles of STTE were designed based on the pectoral fin structure of humpback whales of which the influence on the pressure pulsation of centrifugal pumps was studied via experiment and numerical simulation. Results show that a reasonable design of STTE can effectively eliminate the high-frequency pressure pulsation in the rotor–stator interaction region of the centrifugal pump. The use of STTE2 and STTE3 profiles affect the amplitude reduction of pressure pulsation at the blade passing frequency (fBPF). Compared with the impeller without the STTE profile, the amplitudes of pressure pulsation with STTE2 and STTE3 profiles are decreased by 47.10% and 44.20% at the pump discharge, while the decrease, at the volute throat is 30.36% and 25.97%, respectively. Detailed flow structures inside the pump show that the STTE profile can inhibit the vortex generation at the blade trailing edge, and the local high-intensity pressure pulsation can be reasonably avoided. This study helps improve the pressure pulsation characteristic of centrifugal pumps and their operation stability.
Finite Element Implementation of Biphasic-Fluid Structure Interactions in febio
Authors: Shim Jay J. , Maas Steve A. , Weiss Jeffrey A. , Ateshian Gerard A.
Published: March 2021

In biomechanics, solid–fluid mixtures have commonly been used to model the response of hydrated biological tissues. In cartilage mechanics, this type of mixture, where the fluid and solid constituents are both assumed to be intrinsically incompressible, is often called a biphasic material. Various physiological processes involve the interaction of a viscous fluid with a porous-hydrated tissue, as encountered in synovial joint lubrication, cardiovascular mechanics, and respiratory mechanics. The objective of this study was to implement a finite element solver in the open-source software febio that models dynamic interactions between a viscous fluid and a biphasic domain, accommodating finite deformations of both domains as well as fluid exchanges between them. For compatibility with our recent implementation of solvers for computational fluid dynamics (CFD) and fluid–structure interactions (FSI), where the fluid is slightly compressible, this study employs a novel hybrid biphasic formulation where the porous skeleton is intrinsically incompressible but the fluid is also slightly compressible. The resulting biphasic-FSI (BFSI) implementation is verified against published analytical and numerical benchmark problems, as well as novel analytical solutions derived for the purposes of this study. An illustration of this BFSI solver is presented for two-dimensional (2D) airflow through a simulated face mask under five cycles of breathing, showing that masks significantly reduce air dispersion compared to the no-mask control analysis. In addition, we model three-dimensional (3D) blood flow in a bifurcated carotid artery assuming porous arterial walls and verify that mass is conserved across all fluid–permeable boundaries. The successful formulation and implementation of this BFSI solver offers enhanced multiphysics modeling capabilities that are accessible via an open-source software platform.
Influence of Hydroxyproline on Mechanical Behavior of Collagen Mimetic Proteins Under Fraying Deformation—Molecular Dynamics Investigations
Authors: Rawal Atul , Rhinehardt Kristen L. , Mohan Ram V. , Pendse Max
Published: March 2021

Molecular dynamics modeling is used to simulate, model, and analyze mechanical deformation behavior and predictive properties of three different synthetic collagen proteins obtained from RSC-PDB, 1BKV, 3A08, and 2CUO, with varying concentrations of hydroxyproline (HYP). Hydroxyproline is credited with providing structural support for the collagen protein molecules. Hydroxyproline's influence on these three synthetic collagen proteins' mechanical deformation behavior and predictive properties is investigated in this paper. A detailed study and inference of the protein's mechanical characteristics associated with HYP content are investigated through fraying deformation behavior. A calculated Gibbs free energy value (ΔG) of each polypeptide α chain that corresponds with a complete unfolding of a single polypeptide α-chain from a triple-helical protein is obtained with umbrella sampling. The force needed for complete separation of the polypeptide α-chain from the triple-helical protein is analyzed for proteins to understand the influence of HYP concentration and is discussed in this paper. Along with a difference in ΔG, different unfolding pathways for the molecule and individual chains are observed. The correlation between the fraying deformation mechanical characteristics and the collagen proteins' hydroxyproline content is provided in this study via the three collagen proteins' resulting binding energies.
A Proof-of-Principle Study of the Design and Optimization of a Novel Fluid-Driven Automated Retracting Needle System
Authors: Geelhoed W. J. , Boonekamp M. , van de Stadt H. , Badulescu S. , Lalai R. A. , Groeneweg K. E. , Koning M. , Florijn B. , Horeman T. , Rotmans J. I.
Published: March 2021

The cannulation of blood vessels is one of the most basic and essential interventions in medical practice. A common adverse event of this procedure is miscannulation with infiltration of the second part of the vessel wall, often resulting in a perivascular hematoma. In hemodialysis patients, surgically created arteriovenous conduits are cannulated 3–4 times per week to provide sufficient blood supply to the hemodialysis machine. However, the high blood flow and pressure in these vascular access sites increase the risk of complications upon miscannulation. A novel needle system that allows for rapid automatic retraction of the needle in response to contact with blood after positioning the cannula in the blood vessel was developed to reduce the risk of miscannulation. The device can easily be incorporated into existing needle designs. The mechanical functionality of the device was validated by testing prototypes in an ex vivo system. Optimization of the needle system was performed to enhance response time and piston shape. A final prototype design was manufactured and validated. The optimal membrane composition and piston shape were determined, which resulted in a needle response time of 40 ms upon contact with fluid at a pressure of 100 mmHg (arterial pressure). Here, we have successfully designed, mechanically validated, and tested a novel automated rapid needle retraction system that allows incorporation into existing needle systems. This device could notably decrease the difficulty of vessel cannulation and the prevalence of hematoma formation.
Intermediate Geometric and Interfeature Relationships for Automatic Group Technology Part Coding
Authors: Srikantappa A. B. , Crawford R. H.
Published: March 2021

Group Technology (GT) is a manufacturing philosophy in which similar parts are grouped together to take advantage of their similarities. GT is implemented with a representation that summarizes the important design and manufacturing features of a part in terms of an alphanumeric code. Automated GT coding relies on a complete geometric description of the part, along with a description of the high level manufacturing features such as slots, holes and pockets, and the spatial relationships between these features.

A strategy for the representation and manipulation of interacting and interfeature relationships has been developed. This representation includes a formalism, consisting a set of structural and geometric primitives, along with a methodology for modeling features in the context of interacting and interfeature relationships. This is referred to as the intermediate geometry representation. The information represented includes interactions between features and geometric relationships among features. This paper reports on research to perform automatic GT coding that utilizes the geometric model of the part, the feature model of the part, and the intermediate geometry representation of the part. The interacting and interfeature relationships are shown to significantly facilitate the decision-making processes involved in automated GT coding.
A Simplified Approach for Force and Power-Flow Analysis of Compound Epicyclic Spur-Gear Trains
Authors: Saggere L. , Olson D. G.
Published: March 2021

After conceptual design and dimensional synthesis of a compound epicyclic gear train (EGT), its performance evaluation involves kinematic analysis, force analysis, torque analysis, and power-flow analysis. In recent years, graph theory has proven to be a powerful symbolic representation for design of mechanisms. Application of graph theory for the topological representation and kinematic analysis of EGTs is quite well established. However, graph theory based methods for power-flow and force analysis lack certain features, making them unsuitable or difficult to implement in a general purpose program for automatic design of EGTs. The traditional approach has been to perform force and torque analysis first, and then use the results to perform power-flow analysis. This paper presents a novel, systematic approach in which power-flow analysis is performed first, and then the results are used to determine the inter-link forces in epicyclic spur-gear trains. This method is based only on the graph of the gear-train and the angular velocities of the elements, and hence, is more suitable for automatic computation, simpler to implement in a program, and also avoids requiring the formulation of tedious torque equilibrium equations. A numerical example is presented to illustrate the simplicity and generality of the method.
On the Direct Kinematics of a Class of Spherical Three-Degree-of Freedom Parallel Manipulators
Authors: Gosselin Clément M. , Sefrioui Jaouad , Richard Marc J.
Published: March 2021

This paper presents a polynomial solution to the direct kinematic problem of a class of spherical three-degree-of-freedom parallel manipulators. This class is defined as the set of manipulators for which the axes of the three revolute joints attached to the gripper link are coplanar and symmetrically arranged. It is shown that, for these manipulators, the direct kinematic problem admits a maximum of 8 real solutions. A polynomial of degree 8 is obtained here to support this result and cases for which all the roots of the polynomial lead to real configurations are presented. Finally, the spherical parallel manipulator with collinear actuators, which received some attention in the literature, is also treated and is shown to lead to a minimal polynomial of the same degree. Examples of the application of the method to manipulators of each category are given and solved.
Kinematic Structure Analysis and Classification of Single-Loop Spatial Linkage Mechanisms
Authors: Zhou Y. B. , Fenton R. G.
Published: March 2021

This paper covers the following areas: all practical and typical kinematic input pairs used in a single-loop spatial linkage mechanism (SSLM) are classified using a new symbolic system; four basic groups of SSLMs are defined; and a new kinematic structure classification criterion is proposed, which provides a method to determine the maximum finite number of closures for the mechanism and the maximum order of the input-output displacement equation, free of extraneous roots, describing the kinematics of the SSLMs.
Parametric Deflection Approximations for End-Loaded, Large-Deflection Beams in Compliant Mechanisms
Authors: Howell Larry L. , Midha Ashok
Published: March 2021

Geometric nonlinearities often complicate the analysis of systems containing large-deflection members. The time and resources required to develop closed-form or numerical solutions nave inspired the development of a simple method of approximating the deflection path of end-loaded, large-deflection cantilever beams. The path coordinates are parameterized in a single parameter, called the pseudo-rigid-body angle. The approximations are accurate to within 0.5% of the closed-form elliptic integral solutions. A physical model is associated with the method, and may be used to simplify complex problems. The method proves to be particularly useful in the analysis and design of compliant mechanisms.
Issues on Teaching Kinematics and Mechanism Design
Authors: Erdman Arthur G. , Corrigan Thomas R.
Published: March 2021

The issues, problems and possible solutions involved in teaching a modern course on mechanisms and kinematics are addressed from the perspective of a professor and a student. A historical examination shows the value of modern (computer) solution of classical dilemmas. The structure of an introductory course is then presented, with comments on its educational attributes. The solution of several design problems with LINCAGES©, a computer software package, demonstrates the prowess of the modem student/computer liaison.
Synthesis of Wrapping Cams
Authors: Tidwell Paul H. , Bandukwala Naveed , Dhande Sanjay G. , Reinholtz Charles F. , Webb Greg
Published: March 2021

This paper describes a technique for synthesizing a force generating mechanism composed of a cam wrapped by a belt or chain. Such mechanisms will hereafter be referred to as “wrapping cams.” Synthesis methods for two cases of this mechanism are presented. In the simplest case, the cam is wrapped by a belt or chain under constant tensile force, producing a non-linear torque at the cam. In the second case, the cam is under constant torque, producing a non-linear belt or chain force. While wrapping cams are far less common than cams that generate a specified follower displacement function, applications exist in counter-balancing mechanisms, exercise equipment, and process machines.
Dynamic Analysis of a Spherical Four Bar Mechanism
Authors: Dooley J. R. , McCarthy J. M.
Published: March 2021

Spherical mechanisms are designed so that the points in each link are constrained to move on concentric spheres This paper develops the equations of motion for spherical four bar mechanisms. While the kinematics of these linkages have been extensively studied, the dynamics equations do not seem to have been previously derived. As design techniques for these mechanisms become more efficient, the equations of motion are required to evaluate their performance.

The complete dynamics equations of a four-bar spherical mechanism are derived using the input and output joint angles and the Euler parameters of the coupler as generalized coordinates. These coordinates provide a convenient representation of the constraint equations associated with the closed chain. An example analysis is provided.
Complete Balancing of Linkages Using Complete Dynamical Equivalents of Floating Links: CDEL Method
Authors: Bagci Cemil
Published: March 2021

Partially dynamically equivalent link concept has been used for partial shaking force balancing of the slider-crank mechanisms of engines for a long time. The article offers methods of forming complete dynamically equivalent link (CDEL) for floating binary, ternary, and quaternary links by which a mechanism can be completely balanced eliminating shaking force and shaking moment. Developments and applications are simple. Four-bar and slider-crank mechanisms, Walt’s and Stephenson’s type six-bar mechanisms and some eight-bar mechanisms are completely balanced to illustrate different forms of CDEL in different mechanisms. CDEL uses auxiliary masses and mass moments of inertia on a floating link. The use of the auxiliary masses is illustrated in numerical examples. A Watt’s type body guiding six-bar mechanism interacting with a robot is completely balanced in an application example.
Dynamic Control of Multiple Coordinated Robot Manipulators With Optimal Load Distribution
Authors: Li Chang-Jin , Sankar T. S.
Published: March 2021

The optimal load distribution in multiple robot arm systems, based on minimization of the energy consumption in each collaborating arm, is studied first. Then, for two classes of motion, that is, for trajectory tracking in the joint coordinates and in the object Cartesian coordinates, the corresponding controllers based on the optimal load distribution are developed. Using the joint forces or torques according to the developed controllers can make the actual motion trajectory to asymptotically track the desired trajectory.
Modular Robot Connection Design
Authors: Ambrose Robert O. , Tesar Delbert
Published: March 2021

The ability to reconfigure automation equipment will reduce the manufacturing costs of obsolesence, training and maintenance while allowing for a faster response to changes in the product line. A modular philosophy will give the user these advantages, but only if based on a common connection standard.

A mechanical connection was selected for the UT Modular Robotics Testbed and used in the designs of four robot joint modules and nine robot link modules. The standard was also used for assecories, such as the testand, loading fixtures and endeffectors.

Three years of experiments with this connection standard are reviewed, and used as the basis for new connection designs. Experiments using multiple modules assembled as dextrous robots, as well as experiments focusing on the connection itself, will be described.

Goals for future connection standards include designs with upward compatibility, combinations of both mechanical and electrical fittings, and robot triendly constraints that allow for automated or remote assembly of modular robots.
A Versatile 3-D Tactile Array Gripper Using a Digitally Encoded Sensor
Authors: Friedman Glenn M. , Derby Stephen J.
Published: March 2021

A shape-compliant gripper is proposed that incorporates a matrix array of actuating probes into the fingers. This allows the robot to grasp one of many objects of different surface shapes having arbitrary location and orientation within the grasping envelope. The probes produce a range image by measuring distances between the object’s surface and the sensor plane. The range data is made available to a computer for addressing the problem of identification and localization for flexible assembly, bin sorting, inspection, or other applications.
Deadly viral outbreak ravages European horses
Authors: Lesté-Lasserre Christa
Published: March 2021

Researchers are studying why a common herpesvirus suddenly took a serious toll
Hunting the eagle killer: A cyanobacterial neurotoxin causes vacuolar myelinopathy
Authors: Breinlinger Steffen , Phillips Tabitha J. , Haram Brigette N. , Mareš Jan , Martínez Yerena José A. , Hrouzek Pavel , Sobotka Roman , Henderson W. Matthew , Schmieder Peter , Williams Susan M. , Lauderdale James D. , Wilde H. Dayton , Gerrin Wesley , Kust Andreja , Washington John W. , Wagner Christoph , Geier Benedikt , Liebeke Manuel , Enke Heike , Niedermeyer Timo H. J. , Wilde Susan B.
Published: March 2021

A lethal combination

Although many human activities have clear negative effects on the natural world, there are also unforeseen consequences. Bald eagle mass death events in the southeastern United States may be one such downstream effect of human activity. After considerable effort, Breinlinger
et al.
identified the cause of these events as an insidious combination of factors. Colonization of waterways by an invasive, introduced plant provided a substrate for the growth of a previously unidentified cyanobacterium. Exposure of this cyanobacterium to bromide, typically anthropogenic in origin, resulted in the production of a neurotoxin that both causes neuropathy in animals that prey on the plants and also bioaccumulates to kill predators such as bald eagles.

Science
, this issue p.
eaax9050
A 35-million-year record of seawater stable Sr isotopes reveals a fluctuating global carbon cycle
Authors: Paytan Adina , Griffith Elizabeth M. , Eisenhauer Anton , Hain Mathis P. , Wallmann Klaus , Ridgwell Andrew
Published: March 2021

Carbon cycle history

Marine carbon includes organic and inorganic components, both of which must be accounted for to understand the global carbon cycle. Paytan
et al.
assembled a record of stable strontium isotopes (
88
Sr and
86
Sr) derived from pelagic marine barite and used it to reconstruct changes in the deposition and burial of biogenic calcium carbonate in marine sediments. These data, when combined with measurements of
87
Sr/
86
Sr, can help to reveal past changes in the sources and sinks of strontium, as well as variations in carbonate deposition that affect the carbon cycle.

Science
, this issue p.
1346
Diversity and functional landscapes in the microbiota of animals in the wild
Authors: Levin Doron , Raab Neta , Pinto Yishay , Rothschild Daphna , Zanir Gal , Godneva Anastasia , Mellul Nadav , Futorian David , Gal Doran , Leviatan Sigal , Zeevi David , Bachelet Ido , Segal Eran
Published: March 2021

Animals in the wild are able to subsist on pathogen-infected and poisonous food and show immunity to various diseases. These may be due to their microbiota, yet we have a poor understanding of animal microbial diversity and function. We used metagenomics to analyze the gut microbiota of more than 180 species in the wild, covering diverse classes, feeding behaviors, geographies, and traits. Using de novo metagenome assembly, we constructed and functionally annotated a database of more than 5000 genomes, comprising 1209 bacterial species of which 75% are unknown. The microbial composition, diversity, and functional content exhibit associations with animal taxonomy, diet, activity, social structure, and life span. We identify the gut microbiota of wild animals as a largely untapped resource for the discovery of therapeutics and biotechnology applications.
The molecular assembly of the marsupial γμ T cell receptor defines a third T cell lineage
Authors: Morrissey Kimberly A. , Wegrecki Marcin , Praveena T. , Hansen Victoria L. , Bu Lijing , Sivaraman Komagal Kannan , Darko Samuel , Douek Daniel C. , Rossjohn Jamie , Miller Robert D. , Le Nours Jérôme
Published: March 2021

In non-eutherians, a third type of T cell

The two established T cell lineages found in jawed vertebrates use either an αβ or a γδ T cell receptor (TCR) to detect antigens. Recently, another type of TCR chain (TCRµ) was found in marsupials and monotremes. Morrissey
et al.
analyzed T cells from the gray short-tailed opossum and uncovered a third lineage resident in the spleen that uses a γµ TCR (see the Perspective by Criscitiello). The authors then characterized the crystal structures of two different γµ TCRs, which exhibited an architecture distinct from αβ or γδ TCRs in which a highly diverse, unpaired immunoglobulin-like variable domain was predicted to be the major antigen recognition determinant. Like camelid VHH and shark IgNAR antibodies, γµ TCRs could potentially inform future nanobody development.

Science
, this issue p.
1383
; see also p.
1308
Three-dimensional vectorial imaging of surface phonon polaritons
Authors: Li Xiaoyan , Haberfehlner Georg , Hohenester Ulrich , Stéphan Odile , Kothleitner Gerald , Kociak Mathieu
Published: March 2021

Mapping nanostructure surface excitations

Atomic vibrations (phonons) govern many physical properties of materials, especially those related to heat and thermal transport. They also provide fingerprints of the chemistry of a wide variety of materials, from solids to molecules. The behavior of phonons in nanostructures can be appreciably modified because of confinement effects. Li
et al.
combined several electron microscopy techniques to map out the phonon-polariton excitations across the surface of magnesium oxide nanostructures with high spatial, spectral, and angular resolution. The reconstruction of the surface excitation maps in three dimensions will be useful for understanding and optimizing the properties of the nanostructured materials for advanced functionality.

Science
, this issue p.
1364
Molecular Epidemiology of Third-Generation-Cephalosporin-Resistant
Enterobacteriaceae
in Southeast Queensland, Australia
Authors: Stewart A. G. , Price E. P. , Schabacker K. , Birikmen M. , Harris P. N. A. , Choong K. , Subedi S. , Sarovich D. S.
Published: March 2021

Third-generation cephalosporin-resistant (3GC-R)
Enterobacteriaceae
represent a major threat to human health. Here, we captured 288 3GC-R
Enterobacteriaceae
clinical isolates from 264 patients presenting at a regional Australian hospital over a 14-month period. In addition to identification of isolates to the species level by routine mass spectrometry and antibiotic sensitivity testing, isolates were examined using rapid (∼40-min) real-time PCR assays targeting the most common extended-spectrum β-lactamases (ESBLs;
bla
CTX-M-1
and
bla
CTX-M-9
groups, plus
bla
TEM
,
bla
SHV
, and an internal 16S rRNA gene control).
Activity of β-Lactam Antibiotics against Metallo-β-Lactamase-Producing
Enterobacterales
in Animal Infection Models: a Current State of Affairs
Authors: Asempa Tomefa E. , Abdelraouf Kamilia , Nicolau David P.
Published: March 2021

Metallo-β-lactamases (MBLs) result in resistance to nearly all β-lactam antimicrobial agents, as determined by currently employed susceptibility testing methods. However, recently reported data demonstrate that variable and supraphysiologic zinc concentrations in conventional susceptibility testing media compared with physiologic (bioactive) zinc concentrations may be mediating discordant
in vitro
-
in vivo
MBL resistance.
Comprehensive Investigation on the Interplay between Feline APOBEC3Z3 Proteins and Feline Immunodeficiency Virus Vif Proteins
Authors: Kosugi Yusuke , Uriu Keiya , Suzuki Narumi , Yamamoto Keisuke , Nagaoka Shumpei , Kimura Izumi , Konno Yoriyuki , Aso Hirofumi , Willett Brian J. , Kobayashi Tomoko , Koyanagi Yoshio , Ueda Mahoko Takahashi , Ito Jumpei , Sato Kei
Published: March 2021

Most of the emergences of new virus infections originate from the cross-species transmission of viruses. The fact that some virus infections are strictly specific for the host species indicates that certain “species barriers” in the hosts restrict cross-species jump of viruses, while viruses have evolutionary acquired their own “arms” to overcome/antagonize/neutralize these hurdles.
Comparative Antibody Responses to the Live-Attenuated and Recombinant Herpes Zoster Vaccines
Authors: Schmid D. Scott , Miao Congrong , Leung Jessica , Johnson Michael , Weinberg Adriana , Levin Myron J.
Published: March 2021

These observations further distinguish the immunogenicity and duration of the immune response of the two vaccines. In addition, measurements of functional humoral immunity (IgG avidity and neutralizing antibody) in response to zoster immunization, alone or combined with other immune markers, might contribute to practical
in vitro
correlates of protection.
Newcastle Disease Virus Entry into Chicken Macrophages via a pH-Dependent, Dynamin and Caveola-Mediated Endocytic Pathway That Requires Rab5
Authors: Zhao Ran , Shi Qiankai , Han Zongxi , Fan Zhen , Ai Hui , Chen Linna , Li Le , Liu Tianyi , Sun Junfeng , Liu Shengwang
Published: March 2021

Although the pathogenesis of Newcastle disease virus (NDV) has been extensively studied, the detailed mechanism of NDV entry into host cells is largely unknown. Macrophages are the first-line defenders of host defense against infection of pathogens.
Late Pleistocene rates of rock uplift and faulting at the boundary between the southern Coast Ranges and the western Transverse Ranges in California from reconstruction and luminescence dating of the Orcutt Formation
Authors: McGregor Ian S. , Onderdonk Nathan W.
Published: March 2021

The western Transverse Ranges and southern Coast Ranges of California are lithologically similar but have very different styles and rates of Quaternary deformation. The western Transverse Ranges are deformed by west-trending folds and reverse faults with fast rates of Quaternary fault slip (1–11 mm/yr) and uplift (1–7 mm/yr). The southern Coast Ranges, however, are primarily deformed by northwest-trending folds and right-lateral strike-slip faults with much slower slip rates (3 mm/yr or less) and uplift rates (<1 mm/yr). Faults and folds at the boundary between these two structural domains exhibit geometric and kinematic characteristics of both domains, but little is known about the rate of Quaternary deformation along the boundary.

We used a late Pleistocene sedimentary deposit, the Orcutt Formation, as a marker to characterize deformation within the boundary zone over the past 120 k.y. The Orcutt Formation is a fluvial deposit in the Santa Maria Basin that formed during regional planation by a broad fluvial system that graded into a shoreline platform at the coast. We used post-infrared–infrared-stimulated luminescence (pIR-IRSL) dating to determine that the Orcutt Formation was deposited between 119 ± 8 and 85 ± 6 ka, coincident with oxygen isotope stages 5e-a paleo–sea-level highstands and regional depositional events. The deformed Orcutt basal surface closely follows the present-day topography of the Santa Maria Basin and is folded by northwest-trending anticlines that are a combination of fault-propagation and fault-bend-folding controlled by deeper thrust faults. Reconstructions of the Orcutt basal surface and forward modeling of balanced cross sections across the study area allowed us to measure rock uplift rates and fault slip rates. Rock uplift rates at the crests of two major anticlinoria are 0.9–4.9 mm/yr, and the dip-slip rate along the blind fault system that underlies these folds is 5.6–6.7 mm/yr. These rates are similar to those reported from the Ventura area to the southeast and indicate that the relatively high rates of deformation in the western Transverse Ranges are also present along the northern boundary zone. The deformation style and rates are consistent with models that attribute shortening across the Santa Maria Basin to accommodation of clockwise rotation of the western Transverse Ranges and suggest that rotation has continued into late Quaternary time.