bluuebunny/crossref_metadata_2025 huggingface dataset:
Empowering Graduate Engineering Students With Proficiency in Autonomy
Authors: Raman Adhiti T. , Krovi Venkat N. , Schmid Matthias J. A.
Published: November 2018

A new class of distributed, autonomous systems is emerging, capable of exploiting multimodal distributed and networked spatial and temporal data (at significantly larger scales). A renaissance autonomy engineer requires proficiency in both traditional engineering concepts as well as a systems engineering skillset for implementing the ensuing complex systems.

In this paper, we describe goals, development and first offering of a scaffolded course: “AuE 893 Autonomy: Science and Systems” to begin addressing this goal. Geared towards graduate engineering students, with limited prior exposure, the course complements the concepts from traditional courses (on mobile-robotics) with experiential hands-on system-integration efforts (building on the F1tenth.org kits).

The staged course structure initially builds upon open-source Robotics Operating System (ROS) tutorials on simulated systems (Gazebo/RViz) with networked communication; Hardware-in-the-loop realization (with a Turtlebot platform) then aids the exploration (and reinforcement) of autonomy concepts. The course culminates in a final-project comprising performance testing with student-team integrated scaled Autonomous Remote Control cars (based on the F1tenth.org parts-list). All three student teams were successful in navigating around a closed racecourse at speeds of 10–15 miles per hour, using Simultaneous Localization and Mapping (SLAM) for situational awareness and obstacle-avoidance. We conclude with discussion of lessons-learnt and opportunities for future improvement.
Profile Synthesis of Prismatic-Prismatic Variable Joints for Use in Reconfigurable Mechanisms
Authors: Callahan Ryan D. , Voglewede Philip A.
Published: November 2018

Reconfigurable mechanisms provide increased flexibility in machine design and can be used in a variety of applications. Variable joints in reconfigurable mechanisms allow for machine designs that better optimize space and resources. This paper synthesizes the motion profiles of prismatic-prismatic higher variable joints based upon the configuration space approach. Variable joints enable the creation of Type II Mechanisms with Variable Topology, mechanisms whose topology changes due to changes in joint geometry. The goal of this synthesis is to be able to analyze the motion profile, allowing to understand the design constraints of these joints as well as outline the design for the practical implementation of these joints.
Variable Stiffness Mechanism for Tremor Suppression in Human-Robot Interaction
Authors: Jujjavarapu Sri Sadhan , Karami M. Amin , Esfahani Ehsan T.
Published: November 2018

Variable stiffness mechanisms have a wide range of applications in the field of human-robot interactions such as rehabilitation robotics, prosthesis and industrial robotics due to their ability to comply with the human limb stiffness in an unstructured environment. This paper presents the analysis of a single degree of freedom variable stiffness actuator based on nonlinear force interactions between permanent magnets and its effect on the natural frequency of the system. In the proposed mechanism, variable stiffness is achieved by modifying the separation between magnets. The main goal here is to achieve a desired cutoff frequency by varying the stiffness of the system to filter out the involuntary movement of upper limb during physical human-robot interactions. Moreover, due to the spring-like non-contact force interactions between magnets, this mechanism can prevent the exchange of high impact forces between the robot and human.
A Physics-Based Virtual Environment for Enhancing the Quality of Deep Generative Designs
Authors: Dering Matthew , Cunningham James , Desai Raj , Yukish Michael A. , Simpson Timothy W. , Tucker Conrad S.
Published: November 2018

In this paper, we present a method that uses a physics-based virtual environment to evaluate the feasibility of neural network-based generated designs. Deep learning models rely on large training data sets that are used for training. These training data sets are typically validated by human designers that have a conceptual understanding of the problem being solved. However, the requirement of human training data severely constrains the size and availability of training data for computer generated models due to the manual process of either creating or labeling such data sets. Furthermore, there may be misclassification errors that result from human labeling. To mitigate these challenges, we present a physics-based simulation environment that helps users discover correlations between the form of a generated design and the physical constraints that relate to its function. We hypothesize that training data that includes machine validated designs from a physics-based virtual environment will increase the probability of generative models creating functionally-feasible design concepts. A case study involving a generative model that is trained on over 70,000 human 2D boat sketches is used to test the hypothesis. Knowledge gained from testing this hypothesis will provide human designers with insights into the importance of training data in the resulting design solutions generated by deep neural networks.
Dynamics of a Ring-Type Macro Gyroscope Under Electromagnetic External Actuation Forces
Authors: Gebrel Ibrahim F. , Wang Ligang , Asokanthan Samuel F.
Published: November 2018

This paper investigates the dynamic behaviour of a rotating ring that forms an essential element in ring-based vibratory gyroscopes that utilize oscillatory electromagnetic forces. Understanding the effects of nonlinear actuator dynamics is considered important for characterizing the dynamic behavior of such devices. A suitable theoretical model to generate nonlinear electromagnetic force that acts on the ring structure is formulated. In order to predict the dynamic behaviour of a ring system subjected to external excitation and body rotation, discretized equations obtained via Galerkin’s procedure is employed to investigate the time as well as frequency response behavior. Dynamic response in the driving and the sensing directions are examined via time responses, phase diagram, Poincare’ map and bifurcation plots when the input angular motion and the nonlinear electromagnetic force are considered simultaneously. The analysis is envisaged to aid ongoing experimental research as well as for providing design improvements in Ring-based Gyroscopes.
Research on the Solver of Riccati Transfer Matrix Method for Linear Multibody Systems
Authors: Gu Junjie , Rui Xiaoting , Zhang Jianshu , Chen Gangli
Published: November 2018

Riccati transfer matrix method for multibody systems (RMSTMM) has lower matrix order and better numerical stability than transfer matrix method for multibody systems (MSTMM). In order to make technicians more convenient to apply RMSTMM in practical engineering to improve the computational efficiency of dynamics, in this paper, a linear RMSTMM solver is developed based on the linear RMSTMM theory. A solver input document with good compatibility and extensibility is designed based on extensible markup language (XML); The data structure of multibody system is designed based on object-oriented programming method. The technique of auto selecting the cut hinges of closed-loops of the multibody system is established by introducing the correlation matrix and the dynamic connectivity matrix which depict the connecting state of elements. The automatic generation of the derived tree system by cutting off the closed-loops in the multibody system is realized based on the technique. The automatic regularly numbering of dynamics elements of multibody systems is realized based on the depth first recursive traversal algorithm; Finally, the Riccati transfer matrix recursive technique is implemented based on the regular numbers of dynamics elements of the multibody system. An example is given to verify the effectiveness of the solver which provides a powerful tool for extending the application of RMSTMM in practical engineering.
The Workspace Analysis of Quadruped Robot Regarded As a Parallel Manipulator Under Different Configurations
Authors: Ma Nan , Yu Jingjun
Published: November 2018

The quadruped mammal is one kind of animal that has the excellent motion performances (i.e. walking stability, running speed and body flexibility). Lots of attentions have focused on imitating structure/characteristic of these quadruped animals to promote the development in quadruped robot in recent years. Most of the researches are concentrated on the motion capability analysis of the quadruped robots, However, the workspace variation, which is an important characteristic to scale the static manipulation ability when the quadruped is standing with the four feet fixed on the ground, is ignored by the most of researchers. In this paper, the workspace variation of quadruped robot, when regarded as a parallel manipulator with for foot fixed on ground as a case, is studied using the first generation of MANA robot to explore feet configuration on the influence of workspace variation. This quadruped robot is designed based on the mammal skeleton, which can realize the motion of robot body by alternating the motions in four legs. Firstly, the performance indicators of the MANA are given. Then, the MANA robot is regarded as a parallel platform with four feet fixed on the ground, thus, the corresponding inverse kinematic equations are used to calculate the workspace under the given configuration. After that, variables (i.e. positions of the feet and body posture) are defined to analyze the influence on the workspace variation. At last, four cases are studied to research the overall influence of foot configurations on the workspace variation. The workspace variation analysis of the quadruped can help to optimize the feet configuration for the getting the better manipulator ability, which expands the static performance for quadruped robot.
Workspace Transition of 3-rRPS Metamorphic Parallel Mechanism in Hyperboloid Configuration
Authors: Nurahmi Latifah , Gan Dongming
Published: November 2018

This paper deals with the workspace transition of the 3-rRPS metamorphic parallel mechanism in Hyperboloid configuration. The 3-rRPS metamorphic parallel mechanism is composed of three rRPS legs in which rR joint is reconfigurable. The reconfigurable rR joint allows the moving platform to switch into different Hyperboloid configurations. Two reconfiguration strategies of the mechanism are discussed. In Hyperboloid configurations, the three revolute joint axes are skew and are not parallel to the same plane. These axes can be set with any value within 0° and 90°. By using algebraic geometry approach and Euler parametrization, the workspace of the mechanism is characterized. This workspace is defined as point reachable workspace of any point on the moving platform. The shape of the workspace changes depending on the value of joint parameter angle ϕ. The primary decomposition is computed and it reveals that the 3-rRPS metamorphic parallel mechanism in Hyperboloid configurations can perform 3-dof coupled motions in which the translational motions are completely dependent on the rotational motions.
Effect of the Use of a Noncircular Chainring on the Power Delivered by Recreational Cyclists
Authors: Polanco Alejandra , Tarazona Camilo , Suárez Daniel , Muñoz Luis
Published: November 2018

There is no agreement on the effect that noncircular chainrings have on cyclists when compared with circular ones. In this research, the effect of the use of noncircular chainrings by recreational cyclists is assessed in terms of power delivery indicators. Two complementary approaches based on experimental tests and numerical models are used to study the differences between the results obtained by using circular and noncircular chainrings. The first approach intends to estimate the changes in the transmission system in terms of mechanical advantage when using different chainrings. The model considers that the point of tangency between the chain and the noncircular chainring varies during the rotation. The second approach aims at comparing the power delivery capacity when using different chainrings. A series of constant power tests until exhaustion is performed with each chainring to obtain the power-time relation at different exertion rates.

As a result of this work, a refined model for obtaining the mechanical advantage of the transmission of the bicycle was proposed and validated. Additionally, the effects of the change of the chainring on the cyclists were assessed on a pilot test with two recreational cyclists, registering a change in the behavior of the power delivery capacity during intensive efforts for short periods of time.
From Model-Driven Architecture and Model-Based Systems Engineering via Formal Concept Analysis to Graph-Based Design Languages and Back: A Scientific Discourse
Authors: Schopper Dominik , Rudolph Stephan
Published: November 2018

Most modern digital approaches to engineering are based on models and their model transformations. Most of these model transformations are mathematically speaking non-bijective mappings — so-called projections — where some information of the original model is lost during the mapping. From a theoretical point of view it is therefore of great interest to exactly examine the properties of these model transformations. In this paper at first the characteristics of a model are briefly explained. Then some of the most common model-based engineering approaches are reviewed and compared regarding their models and model transformations. In this examination the missing existence of an inverse transformation (a so-called text-to-model transformation, T2M) of a typical model transformation (a so-called model-to-text transformation, M2T) is identified. That discovery may well hold the key to the realization of a so-called round-trip engineering. The required existence of the inverse transformation to this round-trip engineering is then generically postulated as having the nature of a pattern recognition problem. For illustration purposes and a better understanding of the interpretation of the inverse transformation as a pattern recognition problem, a case study for the reconstruction of an abstract model from the concrete model is given using CAD-Data of a satellite. Since CAD models belong to geometry, dimensionless geometric moment invariants play a key role in the generic solution of the pattern recognition problem contained in this example.
Effect of Fiber Angle Variation on Bending Behavior of Semi-Cylindrical Fiber-Reinforced Soft Actuator
Authors: Darmohammadi Anis , Naeimi Hamid Reza , Agheli Mahdi
Published: November 2018

Soft robots are a specific type of robots that are made of elastomeric materials. A specific type of soft actuators (soft robots) are called fiber-reinforced soft actuators. Effective parameters in the motion of fiber-reinforced soft actuators are cross-section area, thickness of the actuator, number of threads wrapped around the actuator, angle of threads, and if the fiber is wrapped one-way or two-way. Some of these parameters are already studied by researchers in the field. In this research, the aim is to investigate the effect of the angle of the fiber on the motion of a semi-cylindrical fiber-reinforced soft actuator with an inextensible layer attached to its flat surface. This paper studies the behavior analysis of the actuator, which is modeled in a finite element software. The behavior of the actuator in terms of bending is then studied by changing the angle of the fiber wrapped around the outer surface of the actuator. Results show that the bending behavior of the actuator highly depends on the fiber angle. Simulation results are then validated with experiment. The results presented in this paper provides an instruction on how one can improve or optimize the bending workspace of the actuator as needed.
Nonlinear Dynamic Response of Hysteretic Wire Ropes: Modeling and Experiments
Authors: Arena Andrea , Carboni Biagio , Lacarbonara Walter
Published: November 2018

The nonlinear dynamic response of short cables with a tip mass subject to base excitations and undergoing primary resonance is investigated via experimental tests and by employing an ad hoc nonlinear mechanical model. The considered cables are made of several strands of steel wires twisted into a helix forming composite ropes in a pattern known as ‘laid ropes’. Such short span ropes exhibit a hysteretic behavior due to the inter-wire frictional sliding. A nonlinear one-dimensional (1D) continuum model based on the geometrically exact Euler-Bernoulli beam theory is conveniently adapted to describe the cable dynamic response. The Bouc-Wen law of hysteresis is incorporated in the moment-curvature constitutive relationship to reproduce the hysteretic behavior of short steel wire ropes subject to flexural cycles. The frequency response curves show a pronounced softening nonlinearity induced by hysteresis and inertia nonlinearity as confirmed by the experimental data acquired on a wire rope with a tip mass excited at its base by a shaker. The experimental nonlinear resonance response will be exploited to identify the constitutive parameters of the wire rope that best fit the frequency response curves at various forcing amplitudes.
Fatigue Simulation of Automobile Torsion Beam Based on Road Test
Authors: Cui Guo-hua , Xu Feng , Liu Jian , Hou Hongjuan
Published: November 2018

For vehicle structural fatigue life issues considered in the design, fatigue analysis of key parts of the vehicle based on road test and CAE (Computer Aided Engineering) simulation techniques is presented. The rear torsion beam of a vehicle can be used as an example. Firstly, the unit load stress field is calculated by the principle of inertia release after the establishment of the torsion beam finite element model; Then, establishing vehicle rigid coupling model, and making six-component test site collection wheel center as a multi-body simulation input, torsion beam rear obtain the required load spectrum of fatigue analysis; The ground test data is provided for verifying the reliability of the model and the modified model parameters; Finally, Stress influence coefficient method is used for the torsion beam fatigue life prediction. What’s more, simulation results are compared with the road test results. The results show that this method can ensure the accuracy of the finite element model for fatigue analysis and boundary conditions, so that the fatigue life of the torsion beam rear car simulation analysis is more accurate. Provides a theoretical basis for fatigue analysis based on the structural design and Improvement of the rear torsion beam of vehicle. The method is also applicable to the fatigue analysis of other vehicle parts.
Test-Retest Reliability of the 7-Factor Motives for Playing Drinking Games Scale and its Associations With Drinking Game Behaviors Among Female College Athletes
Authors: Zamboanga Byron L. , Kearns Nathan T. , Olthuis Janine V. , Blumenthal Heidemarie , Cloutier Renee M.
Published: November 2018

Drinking games (DGs) participation is prevalent among college-attending emerging adults. Research also suggests that student-athletes play DGs more frequently than non student-athletes, but what motivates student-athletes to participate in DGs is not well understood. Using data from a larger longitudinal study with Division III female athletes, we examined the test-retest reliability and minimal detectable change of the revised 7-factor Motives for Playing Drinking Games (MPDG) measure, and explored how its subscales were related to DGs behavior across two annual timepoints (n = 49). Results indicated that the MPDG shows adequate test-retest reliability over a one year period among student-athletes. Controlling for age and general alcohol consumption, conformity motives were positively associated with DG consumption at timepoint 1, whereas the DG motives of enhancement/thrills and boredom were positively related to DG consumption at timepoint 2. Implications for future research directions on motives for playing DGs and DGs behavior among student-athletes are discussed.
Youth climate trial showcases science
Authors: Rosen Julia
Published: November 2018

Government won't dispute climate change, but will cast doubt on claimed harms.
S&T Policy Fellowships find a home in the judiciary
Authors: Ham Becky
Published: November 2018

Fellows work on independent research topics during their year at the Federal Judicial Center
Advances in flow batteries promise cheap backup power
Authors: Service Robert F.
Published: November 2018

Upstart technology could enable widespread adoption of renewables.
Universal protection against influenza infection by a multidomain antibody to influenza hemagglutinin
Authors: Laursen Nick S. , Friesen Robert H. E. , Zhu Xueyong , Jongeneelen Mandy , Blokland Sven , Vermond Jan , van Eijgen Alida , Tang Chan , van Diepen Harry , Obmolova Galina , van der Neut Kolfschoten Marijn , Zuijdgeest David , Straetemans Roel , Hoffman Ryan M. B. , Nieusma Travis , Pallesen Jesper , Turner Hannah L. , Bernard Steffen M. , Ward Andrew B. , Luo Jinquan , Poon Leo L. M. , Tretiakova Anna P. , Wilson James M. , Limberis Maria P. , Vogels Ronald , Brandenburg Boerries , Kolkman Joost A. , Wilson Ian A.
Published: November 2018

Durable influenza protection

Vaccines are indispensable for the control and prevention of influenza, but there are several challenges to efficacy. Some individuals respond poorly to vaccination, and virus variation makes targeting optimal antigens difficult. Broadly neutralizing antibodies are one solution, but they have their own pitfalls, including limited cross-reactivity to both influenza A and B strains and the need for repeated injections. Now, Laursen
et al.
have developed multidomain antibodies with breadth and potency. Administered intranasally to mice with an adeno-associated virus vector, the antibodies provided durable and continuous protection from a panoply of influenza strains.

Science
, this issue p.
598
Composites with carbon nanotubes and graphene: An outlook
Authors: Kinloch Ian A. , Suhr Jonghwan , Lou Jun , Young Robert J. , Ajayan Pulickel M.
Published: November 2018

Composite materials with carbon nanotube and graphene additives have long been considered as exciting prospects among nanotechnology applications. However, after nearly two decades of work in the area, questions remain about the practical impact of nanotube and graphene composites. This uncertainty stems from factors that include poor load transfer, interfacial engineering, dispersion, and viscosity-related issues that lead to processing challenges in such nanocomposites. Moreover, there has been little effort to identify selection rules for the use of nanotubes or graphene in composite matrices for specific applications. This review is a critical look at the status of composites for developing high-strength, low-density, high-conductivity materials with nanotubes or graphene. An outlook of the different approaches that can lead to practically useful nanotube and graphene composites is presented, pointing out the challenges and opportunities that exist in the field.
Poly(ADP-ribose) drives pathologic α-synuclein neurodegeneration in Parkinson’s disease
Authors: Kam Tae-In , Mao Xiaobo , Park Hyejin , Chou Shih-Ching , Karuppagounder Senthilkumar S. , Umanah George Essien , Yun Seung Pil , Brahmachari Saurav , Panicker Nikhil , Chen Rong , Andrabi Shaida A. , Qi Chen , Poirier Guy G. , Pletnikova Olga , Troncoso Juan C. , Bekris Lynn M. , Leverenz James B. , Pantelyat Alexander , Ko Han Seok , Rosenthal Liana S. , Dawson Ted M. , Dawson Valina L.
Published: November 2018

PAR promotes α-synuclein toxicity

How pathologic α-synuclein (α-syn) leads to neurodegeneration in Parkinson's disease (PD) remains poorly understood. Kam
et al.
studied the α-syn preformed fibril (α-syn PFF) model of sporadic PD (see the Perspective by Brundin and Wyse). They found that pathologic α-syn–activated poly(adenosine 5′-diphosphate–ribose) (PAR) polymerase–1 (PARP-1) and inhibition of PARP or knockout of PARP-1 protected mice from pathology. The generation of PAR by α-syn PFF–induced PARP-1 activation converted α-syn PFF to a strain that was 25-fold more toxic, termed PAR–α-syn PFF. An increase of PAR in the cerebrospinal fluid and evidence of PARP activation in the substantia nigra of PD patients indicates that PARP activation contributes to the pathogenesis of PD through parthanatos and conversion of α-syn to a more toxic strain.

Science
, this issue p.
eaat8407
; see also p.
521
Composites from renewable and sustainable resources: Challenges and innovations
Authors: Mohanty Amar K. , Vivekanandhan Singaravelu , Pin Jean-Mathieu , Misra Manjusri
Published: November 2018

Interest in constructing composite materials from biosourced, recycled materials; waste resources; and their combinations is growing. Biocomposites have attracted the attention of automakers for the design of lightweight parts. Hybrid biocomposites made of petrochemical-based and bioresourced materials have led to technological advances in manufacturing. Greener biocomposites from plant-derived fiber and crop-derived plastics with higher biobased content are continuously being developed. Biodegradable composites have shown potential for major uses in sustainable packaging. Recycled plastic materials originally destined for landfills can be redirected and repurposed for blending in composite applications, thus leading to reduced dependence on virgin petro-based materials. Studies on compatibility of recycled and waste materials with other components in composite structure for improved interface and better mechanical performance pose major scientific challenges. This research holds the promise of advancing a key global sustainability goal.
Efficient cortical coding of 3D posture in freely behaving rats
Authors: Mimica Bartul , Dunn Benjamin A. , Tombaz Tuce , Bojja V. P. T. N. C. Srikanth , Whitlock Jonathan R.
Published: November 2018

Posture in the brain

Our understanding of the neural basis of motor control originates in studies of eye, hand, and arm movements in primates. Mimica
et al.
investigated neuronal representations of body postures in the posterior parietal and frontal motor cortices with three-dimensional tracking of freely moving rodents (see the Perspective by Chen). Both brain regions represented posture rather than movements and self-motion. Decoding the activity of neurons in the two regions accurately predicted an animal's posture.

Science
, this issue p.
584
; see also p.
520
Topological protection of biphoton states
Authors: Blanco-Redondo Andrea , Bell Bryn , Oren Dikla , Eggleton Benjamin J. , Segev Mordechai
Published: November 2018

Protecting entangled pairs

Photons are readily generated, are fast and can travel vast distances, and are ideal carriers of quantum information. Practical applications, such as quantum computing, will likely be based on an optical-chip platform and require the manipulation of multiphoton states. The inevitable scattering and loss of photons in such a platform would be detrimental for application. Blanco-Redondo
et al.
show how a specially designed optical circuit based on topology can offer protection for propagating biphoton states. The results show that topological design consideration could provide the desired robustness required for quantum optical circuitry.

Science
, this issue p.
568
Pushing the limits of electron ptychography
Authors: Lupini Andrew R. , Oxley Mark P. , Kalinin Sergei V.
Published: November 2018

Subatomic probe sizes in convergent-beam electron microscopy offer new opportunities
Clonal expansion and compartmentalized maintenance of rhesus macaque NK cell subsets
Authors: Wu Chuanfeng , Espinoza Diego A. , Koelle Samson J. , Yang Di , Truitt Lauren , Schlums Heinrich , Lafont Bernard A. , Davidson-Moncada Jan K. , Lu Rong , Kaur Amitinder , Hammer Quirin , Li Brian , Panch Sandhya , Allan David A. , Donahue Robert E. , Childs Richard W. , Romagnani Chiara , Bryceson Yenan T. , Dunbar Cynthia E.
Published: November 2018

Macaque barcoding reveals NK oligoclonal expansion and persistence independent of production from HSPCs or immature NK cells.
Microbiological Profile of Sarecycline, a Novel Targeted Spectrum Tetracycline for the Treatment of Acne Vulgaris
Authors: Zhanel George , Critchley Ian , Lin Lynn-Yao , Alvandi Nancy
Published: November 2018

Sarecycline is the first narrow-spectrum tetracycline-class antibiotic being developed for acne treatment. In addition to exhibiting activity against important skin/soft tissue pathogens, sarecycline exhibits targeted antibacterial activity against clinical isolates of
Cutibacterium acnes
.
A Type I Restriction-Modification System Associated with Enterococcus faecium Subspecies Separation
Authors: Huo Wenwen , Adams Hannah M. , Trejo Cristian , Badia Rohit , Palmer Kelli L.
Published: November 2018

Enterococcus faecium
is a leading cause of hospital-acquired infections around the world. Rising antibiotic resistance in certain
E. faecium
lineages leaves fewer treatment options. The overarching aim of this work was to determine whether restriction-modification (R-M) systems contribute to the structure of the
E. faecium
species, wherein hospital-epidemic and non-hospital-epidemic isolates have distinct evolutionary histories and highly resolved clade structures. R-M provides bacteria with a type of innate immunity to horizontal gene transfer (HGT). We identified a type I R-M system that is enriched in the hospital-epidemic clade and determined that it is active for DNA modification activity and significantly impacts HGT. Overall, this work is important because it provides a mechanism for the observed clade structure of
E. faecium
as well as a mechanism for facilitated gene exchange among hospital-epidemic
E. faecium
isolates.
Absence of β6 Integrin Reduces Influenza Disease Severity in Highly Susceptible Obese Mice
Authors: Meliopoulos Victoria , Livingston Brandi , Van de Velde Lee-Ann , Honce Rebekah , Schultz-Cherry Stacey
Published: November 2018

Obesity is a risk factor for developing severe influenza virus infection. However, the reasons for this are unknown. We found that the lungs of obese mice have increased expression of the epithelial integrin β6, a host factor associated with increased disease severity. Knocking out integrin β6 in obese mice favorably altered the pulmonary environment by increasing type I IFN signaling, resulting in decreased viral spread, reduced lung injury, and increased survival. This study furthers our understanding of influenza virus pathogenesis in the high-risk obese population and may potentially lead to the development of novel therapies for influenza virus infection.
Advances in Molecular Epidemiology of Infectious Diseases: Definitions, Approaches, and Scope of the Field
Authors: Riley Lee W. , Blanton Ronald E.
Published: November 2018

Molecular epidemiology is a discipline that uses molecular microbiology tools to study the distribution and determinants of diseases in human populations and veterinary animals. Our understanding of epidemiology of infectious diseases has evolved with technological advancements made in molecular biology that refine our perception of the identity and dynamics of microorganisms. This review is an introduction to theMicrobiology SpectrumCurated Collection: Advances in Molecular Epidemiology of Infectious Diseases that will discuss how these advancements have contributed to investigations of infectious disease outbreaks/epidemics, surveillance, transmission dynamics, risk factor identification, pathogenesis, and etiologic attribution of bacterial, viral, protozoan, and helminthic pathogens to a disease. Here we define “molecular epidemiology” and distinguish it from other disciplines that use many of the same molecular biology tools—taxonomy, phylogenetics, and molecular evolution of microorganisms. The Curated Collection will be spread throughout multiple issues ofMicrobiology Spectrumand will be divided into four general sections: (i) laboratory methods used to strain type microbial pathogens, (ii) methods used to analyze genotyping data, (iii) examples of molecular epidemiologic investigations of bacterial, viral, and parasitic diseases, and (iv) applications of molecular epidemiology to address new research questions in communicable and noncommunicable diseases. The major theme of this Curated Collection is to address the following question frequently asked by clinicians, clinical microbiologists, and public health professionals: what is the advantage or unique contribution of molecular epidemiology in solving infectious disease problems in the clinical and public health arenas?*

This article is part of a curated collection.
Trainee-led versus specialist-led management of neovascular age-related macular degeneration: a registry-based study
Authors: Essex Rohan W , Nguyen Vuong , Daien Vincent , Steinmann Sarah , Walton Richard , Gillies Mark C , Barthelmes Daniel
Published: November 2018

Objective

To compare the outcomes of trainee-led and specialist-led management of neovascular age-related macular degeneration.

Design

Prospective multicentre registry-based observational study.

Setting

Ophthalmology training centres in Australia and Europe where both trainee-led and specialist-led models of care coexist.

Participants

Treatment-naïve eyes with neovascular age-related macular degeneration and at least 12 months follow-up. 726 eyes were included in the study from two centres, 534 receiving trainee-led treatment and 192 specialist-led treatment.

Interventions

The management and outcomes of patients receiving trainee-led care were compared with those receiving specialist-led care.

Main outcomes measures

The primary outcome was the mean change in visual acuity at 12 months from first injection. Outcomes were also presented at 36 months where available.

Results

The mean age of participants was 79 years and 65% were female. The adjusted change in acuity at 12 months in trainee-led vs specialist-led eyes was +3.2 letters vs +4.1 letters (difference −0.9 letters, 95% CI −3.4 to 1.5, p=0.473). The mean adjusted change in acuity at 36 months was −0.9 letters in trainees vs +0.2 letters for specialists (difference −1.1 letters, 95% CI −5.1 to 2.9, p=0.596). Eyes treated by trainees received fewer injections on average to 36 months (15.0 vs 19.0, p=0.004), although this trend was observed at one centre only.

Conclusions

No significant differences in outcome between eyes managed by trainees and eyes managed by specialists were observed. Appropriately structured trainee-led management of neovascular age-related macular degeneration is a reasonable approach where regulatory and practical considerations allow it.
Sports Biostatistician: a critical member of all sports science and medicine teams for injury prevention
Authors: Casals Martí , Finch Caroline F
Published: November 2018

Sports science and medicine need specialists to solve the challenges that arise with injury data. In the sports injury field, it is important to be able to optimise injury data to quantify injury occurrences, understand their aetiology and most importantly, prevent them. One of these specialty professions is that of Sports Biostatistician. The aim of this paper is to describe the emergent field of Sports Biostatistics and its relevance to injury prevention. A number of important issues regarding this profession and the science of sports injury prevention are highlighted. There is a clear need for more multidisciplinary teams that incorporate biostatistics, epidemiology and public health in the sports injury area.
Impact of a treatment escalation/limitation plan on non-beneficial interventions and harms in patients during their last admission before in-hospital death, using the Structured Judgment Review Method
Authors: Lightbody Calvin J , Campbell Jonathan N , Herbison G Peter , Osborne Heather K , Radley Alice , Taylor D Robin
Published: November 2018

Objectives

To assess the effect of using a treatment escalation/limitation plan (TELP) on the frequency of harms in 300 patients who died following admission to hospital.

Design

A retrospective case note review of 300 unselected, consecutive deaths comprising: (1) patients with a TELP in addition to a do-not-attempt cardiopulmonary resuscitation order (DNACPR); (2) those with DNACPR only; and (3) those with neither. Patient deaths were classified retrospectively as ‘expected’ or ‘unexpected’ using the Gold Standard Framework Prognostic Indicator Guidance.

Setting

Medical, surgical and intensive care units of a district general hospital.

Outcomes

The primary outcome was the between-group difference in rates of harms, non-beneficial interventions (NBIs) and clinical ‘problems’ identified using the Structured Judgement Review Method.

Results

289 case records were evaluable. 155 had a TELP and DNACPR (54%); 113 had DNACPR only (39%); 21 had neither (7%). 247 deaths (86%) were ‘expected’. Among patients with ‘expected’ deaths and using the TELP/DNACPR as controls (incidence rate ratio (IRR)=1.00), the IRRs were: for harms, 2.99 (DNACPR only) and 4.00 (neither TELP nor DNACPR) (p<0.001 for both); for NBIs, the corresponding IRRs were 2.23 (DNACPR only) and 2.20 (neither) (p<0.001 and p<0.005, respectively); for ‘problems’, 2.30 (DNACPR only) and 2.76 (neither) (p<0.001 for both). The rates of harms, NBIs and ‘problems’ were significantly lower in the group with a TELP/DNACPR compared with ‘DNACPR only’ and ‘neither’: harms (per 1000 bed days) 17.1, 76.9 (p<0.001) and 197.8 (p<0.001) respectively; NBIs: 27.4, 92.1 (p<0.001) and 172.4 (p<0.001); and ‘problems’: 42.3, 146.2 (p<0.01) and 333.3 (p<0.001).

Conclusions

The use of a TELP was associated with a significant reduction in harms, NBIs and ‘problems’ in patients admitted acutely and who subsequently died, especially if they were likely to be in the last year of life.
Different levels of facial expression recognition in patients with first-episode schizophrenia: A functional MRI study
Authors: Yang Chengqing , Qi Ansi , Yu Huangfang , Guan Xiaofeng , Wang Jijun , Liu Na , Zhang Tianhong , Li Hui , Zhou Hui , Zhu Junjuan , Huang Nan , Tang Yingying , Lu Zheng
Published: November 2018

Background

The impairment of facial expression recognition has become a biomarker for early identification of first-episode schizophrenia, and this kind of research is increasing.

Aims

To explore the differences in brain area activation using different degrees of disgusted facial expression recognition in antipsychotic-naïve patients with first-episode schizophrenia and healthy controls.

Methods

In this study, facial expression recognition tests were performed on 30 first-episode, antipsychotic-naïve patients with schizophrenia (treatment group) and 30 healthy subjects (control group) with matched age, educational attainment and gender. Functional MRI was used for comparing the differences of the brain areas of activation between the two groups.

Results

The average response time difference between the patient group and the control group in the ‘high degree of disgust’ facial expression recognition task was statistically significant (1.359 (0.408)/2.193 (0.625), F=26.65, p<0.001), and the correct recognition rate of the treatment group was lower than that of the control group (41.05 (22.25)/59.84 (13.91, F=19.81, p<0.001). Compared with the control group, the left thalamus, right lingual gyrus and right middle temporal gyrus were negatively activated in the patients with first-episode schizophrenia in the ‘high degree of disgust’ emotion recognition, and there was a significant activation in the left and right middle temporal gyrus and the right caudate nucleus. However, there was no significant activation difference in the ‘low degree of disgust’ recognition.

Conclusions

In patients with first-episode schizophrenia, the areas of facial recognition impairment are significantly different in different degrees of disgust facial expression recognition.
The prospective relationship between social cohesion and depressive symptoms among older adults from Central and Eastern Europe
Authors: Bertossi Urzua Carla , Ruiz Milagros A , Pajak Andrzej , Kozela Magdalena , Kubinova Ruzena , Malyutina Sofia , Peasey Anne , Pikhart Hynek , Marmot Michael , Bobak Martin
Published: November 2018

Background

Social cohesion has a potential protective effect against depression, but evidence for Central and Eastern Europe is lacking. We investigated the prospective association between social cohesion and elevated depressive symptoms in the Czech Republic, Russia and Poland, and assessed whether alcohol drinking and smoking mediated this association.

Methods

Cohort data from 15 438 older urban participants from the Health, Alcohol and Psychosocial factors In Eastern Europe project were analysed. Baseline social cohesion was measured by five questions, and depressive symptoms were measured 3 years later by the 10-item Center for Epidemiological Depression (CES-D) Scale. Nested logistic regression models estimated ORs of elevated depressive symptoms (CES-D 10 score ≥4) by z-scores and tertiles of social cohesion.

Results

Per 1 SD decrease in social cohesion score, adjusted ORs of elevated depressive symptoms were 1.13 (95% CI 1.05 to 1.23) and 1.05 (95% CI 0.99 to 1.13) in men and women, respectively. Further adjustment for smoking and drinking did not attenuate these associations in either men (OR=1.13, 95% CI 1.05 to 1.22) or women (OR=1.05, 95% CI 0.99 to 1.13). Similarly, the fully adjusted ORs comparing the lowest versus highest social cohesion tertile were 1.33 (95% CI 1.10 to 1.62) in men and 1.18 (95% CI 1.01 to 1.39) in women.

Conclusions

Lower levels of social cohesion was associated with heightened depressive symptoms after a 3-year follow-up among older Czech, Russian and Polish adults. These effects appeared stronger in men, and alcohol and smoking played no appreciable role in this association.
Fas activation alters tight junction proteins in acute lung injury
Authors: Herrero Raquel , Prados Lucia , Ferruelo Antonio , Puig Ferranda , Pandolfi Rachele , Guillamat-Prats Raquel , Moreno Laura , Matute-Bello Gustavo , Artigas Antonio , Esteban Andres , Lorente José Ángel
Published: November 2018

Background:The acute respiratory distress syndrome (ARDS) is characterized by protein-rich oedema in the alveolar spaces, a feature in which Fas-mediated apoptosis of the alveolar epithelium has been involved.

Objective:To determine whether Fas activation increases protein permeability by mechanisms involving disruption of the paracellular tight junction (TJ) proteins in the pulmonary alveoli.

Methods:Protein permeability and the expression of TJ proteins were assessed in vivo in wild-type and Fas-deficient lpr mice 16 hours after the intratracheal instillation of recombinant human soluble Fas ligand (rh-sFasL), and at different time points in vitro in human pulmonary alveolar epithelial cells (HPAEpiC) exposed to rh-sFasL

Results:Activation of the Fas pathway increased protein permeability in mouse lungs and altered the expression of the TJ proteins occludin and zonula occludens-1 in the alveolar–capillary membrane in vivo and in human alveolar epithelial cell monolayers in vitro. Blockade of caspase-3, but not inhibition of tyrosine kinase dependent pathways, prevented the alterations in TJ protein expression and permeability induced by the Fas/FasL system in human alveolar cell monolayers in vitro. We also observed that both the Fas-induced increase of protein permeability and disruption of TJ proteins occurred before cell death could be detected in the cell monolayers in vitro.

Conclusion:Targeting caspase pathways could prevent the disruption of TJs and reduce the formation of lung oedema in the early stages of ARDS.
Histopathological and biochemical changes in the development of nonalcoholic fatty liver disease induced by high-sucrose diet at different times
Authors: Acosta-Cota Selene de Jesús , Aguilar-Medina Elsa Maribel , Ramos-Payán Rosalio , Ruiz-Quiñónez Ana Karen , Romero-Quintana José Geovanni , Montes-Avila Julio , Rendón-Maldonado José Guadalupe , Sánchez-López Araceli , Centurión David , Osuna-Martínez Ulises
Published: November 2018

The high intake of sweetened drinks is associated with obesity and insulin resistance. These pathologies are directly related to the development of nonalcoholic fatty liver disease (NAFLD), considered a condition of metabolic syndrome (MS). Due to their increasing worldwide prevalence, experimental animal models have been developed to gain a better understanding of its physiopathology; notwithstanding, few studies have evaluated its progression in association with MS and ingestion of sweetened drinks. Therefore, the aim of this study was to understand the pathophysiologic characteristics of NAFLD related to sucrose concentration and time of ingestion in rats. Wistar rats were divided into 2 groups with free access to either tap water or 30% sucrose, and euthanized at 12, 16, or 20 weeks; and 2 additional groups were given free access to either 40% or 50% sucrose and were euthanized at 20 weeks. Biochemical parameters and levels of serum cytokines were measured, and histology was performed. Ingestion of 30% sucrose induced liver steatosis until 16 weeks (grade 2) and 20 weeks (grade 3). Meanwhile, during 20 weeks, 40% sucrose induced grade 5 of nonalcoholic steatohepatitis (NASH) and 50% sucrose induced grade 6 of NASH and fibrosis. This study demonstrated that increasing time of induction and concentration of sucrose ingestion resulted in a higher grade of NAFLD.
Black brane solution in Rastall AdS massive gravity and viscosity bound
Authors: Sadeghi Mehdi
Published: November 2018

In this paper, we introduced the black brane solution in Rastall theory and in the context of massive gravity. The ratio of shear viscosity to entropy density is calculated for this solution. Our result shows that the KSS bound violates this theory.
Phase transition induced by an external field in a three-dimensional isotropic Heisenberg antiferromagnet
Authors: Neto Minos A. , Viana J. Roberto , Salmon Octavio D. R. , Filho E. Bublitz , de Sousa José Ricardo
Published: November 2018

The critical frontier of the isotropic antiferromagnetic Heisenberg model in a magnetic field along the z-axis has been studied by mean-field and effective-field renormalization group calculations. These methods, abbreviated as MFRG and EFRG, are based on the comparison of two clusters of different sizes, each of them trying to mimic a specific Bravais lattice. The frontier line in the plane of temperature versus magnetic field was obtained for the simple cubic and the body-centered cubic lattices. Spin clusters with sizes N = 1, 2, 4 were used so as to implement MFRG-12, EFRG-12 and EFRG-24 numerical equations. For the simple cubic lattice, the MFRG frontier exhibits a notorious re-entrant behavior. This problem is improved by the EFRG technique. However, both methods agree at lower fields. For the body-centered cubic lattice, the MFRG method did not work. As in the cubic lattice, all the EFRG results agree at lower fields. Nevertheless, the EFRG-12 approach gave no solution for very low temperatures. Comparisons with other methods have been discussed.
Connectedness of nonseparating disk pants graph of a handlebody
Authors: Sun Dongqi
Published: November 2018

In this paper, we introduce the definition of nonseparating disk pants graph for a handlebody, and prove that for [Formula: see text], the nonseparating disk pants graph is connected.