bluuebunny/crossref_metadata_2025 huggingface dataset:
Backstepping-Based Trajectory Tracking for Underwater Gliders
Authors: Coleman Demetris , Castaño Maria , Ennasr Osama , Tan Xiaobo
Published: November 2019

Autonomous underwater gliders have become valuable tools for a myriad of applications ranging from ocean exploration to fish tracking to environmental sampling. To be suitable for these types of applications, precise sensing and monitoring is desired, which makes accurate trajectory control important. However, highly nonlinear under-actuated dynamics present significant challenges in control of gliders. In this work a backstepping-based controller is proposed for an underwater glider to track a desired position and heading reference in the sagittal plane with only two control inputs, the buoyancy and center of gravity along the longitudinal direction. In particular,the under-actuation issue is addressed by exploiting the coupled dynamics and introducing a new modified error that combines the tracking errors of heading and position references. In addition, an auxiliary system is incorporated to account for input constraints. Finally, a sliding mode observer is designed to obtain the estimates of body-fixed velocities, to facilitate practical implementation of the designed controller. The effectiveness of the proposed control scheme is demonstrated via simulations and its advantages are shown via comparison with a PID controller.
Toward Magneto-Electroactive Endoluminal Soft (MEESo) Robots
Authors: Steiner Jake A. , Hussain Omar A. , Pham Lan N. , Abbott Jake J. , Leang Kam K.
Published: November 2019

This paper introduces a magneto-electroactive endoluminal soft (MEESo) robot concept, which could enable new classes of catheters, tethered capsule endoscopes, and other mesoscale soft robots designed to navigate the natural lumens of the human body for a variety of medical applications. The MEESo locomotion mechanism combines magnetic propulsion with body deformation created by an ionic polymer-metal composite (IPMC) electroactive polymer. A detailed explanation of the MEESo concept is provided, including experimentally validated models and simulated magneto-electroactive actuation results demonstrating the locomotive benefits of incorporating an IPMC compared to magnetic actuation alone.
Adaptive Control of Large-Scale Soft Robot Manipulators With Unknown Payloads
Authors: Terry Jonathan S. , Whitaker Justin , Beard Randal W. , Killpack Marc D.
Published: November 2019

The compliance and other nonlinear dynamics of large-scale soft robots makes effective control difficult. This is especially true when working with unknown payloads or when the system dynamics change over time which is likely to happen for soft robots. In this paper, we present a novel method of coupling model reference adaptive control (MRAC) with model predictive control (MPC) for platforms with antagonistic pneumatic actuators. We demonstrate its utility on a fully inflatable, six degree-of-freedom pneumatically actuated soft robot manipulator that is over two meters long. Specifically, we compare control performance with no integral controller, with an integral controller, and with MRAC when running a nominal model predictive controller with significant weight attached to the end effector.
A Stabilizing Control Algorithm for Asynchronous Parallel Quadratic Programming via Dual Decomposition
Authors: Lee Kooktae
Published: November 2019

Publisher’s Note:

This paper was selected for publication in ASME Letters in Dynamic Systems and Control.

https://www.asmedigitalcollection.asme.org/lettersdynsys/article/doi/10.1115/1.4046365/1074564/A-Stabilizing-Control-Algorithm-for-Asynchronous
Contagion Processes Over Temporal Networks With Time-Varying Backbones
Authors: Nadini Matthieu , Rizzo Alessandro , Porfiri Maurizio
Published: November 2019

Predicting the diffusion of real-world contagion processes requires a simplified description of human-to-human interactions. Temporal networks offer a powerful means to develop such a mathematically-transparent description. Through temporal networks, one may analytically study the co-evolution of the contagion process and the network topology, as well as incorporate realistic feedback-loop mechanisms related to individual behavioral changes to the contagion. Despite considerable progress, the state-of-the-art does not allow for studying general time-varying networks, where links between individuals dynamically switch to reflect the complexity of social behavior. Here, we tackle this problem by considering a temporal network, in which reducible, associated with node-specific properties, and irreducible links, describing dyadic social ties, simultaneously vary over time. We develop a general mean field theory for the Susceptible-Infected-Susceptible model and conduct an extensive numerical campaign to elucidate the role of network parameters on the average degree of the temporal network and the epidemic threshold. Specifically, we describe how the interplay between reducible and irreducible links influences the disease dynamics, offering insights towards the analysis of complex dynamical networks across science and engineering.
Voltage Response of Parametric Resonance of MEMS Circular Plates Under Hard Excitations
Authors: Beatriz Julio S. , Caruntu Dumitru I.
Published: November 2019

This work deals with the voltage response of parametric resonance of electrostatically actuated microelectromechanical (MEMS) circular plates under hard excitations. Method of Multiple Scales (MMS) and Reduced Order Model (ROM) method using two modes of vibration are used to predict the voltage-amplitude response of the MEMS circular plates. ROM is solved using AUTO 07p, a software package for continuation and bifurcation. MMS used in this paper has one term in the electrostatic force being considered significant. This is the way MMS is used to model hard excitations. MMS shows results similar to those of ROM at lower amplitudes and lower voltages. The differences between the two methods, MMS and ROM, are significant in high amplitudes for all voltages, and the differences are significant in all amplitudes for larger voltages. Significant differences can be noted in the effect of different parameters such as the detuning frequency and damping on the voltage response. ROM AUTO 07p is calibrated using ROM time responses in which the ROM is solved using the solver ode15s in Matlab.
Fused Model Predictive Control Techniques for Strategic Platooning Amongst Heterogeneous Pairs of Heavy-Duty Trucks
Authors: Earnhardt Christian , Groelke Ben , Borek John , Vermillion Chris
Published: November 2019

With pairs or groups of heterogeneous vehicles (with different masses, aerodynamic coefficients, etc.), collaborative platooning can be advantageous in some scenarios due to aerodynamic drag reduction, while being detrimental in other scenarios due to mismatches in vehicle properties. This paper introduces two controllers capable of alternating between independent vehicle velocity trajectory optimization (VTO) and a collaborative platooning/VTO approach based on the aggregate fuel savings of all vehicles within the platoon. The first uses the difference in mass between the vehicles within a platoon and the upcoming road grade to decide whether platooning will be economically advantageous, relying on a support vector classification algorithm to make the switching decision. The second runs both independent VTO and collaborative VTO/platooning in parallel, making a decision based on which method predicts the least amount of fuel consumption over an upcoming stretch of highway. The performance of these techniques was evaluated using a medium-fidelity Simulink model of a heavy-duty truck. Results show a 5.1% to 14.1% decrease in fuel consumption for the following vehicle of a platoon as compared to a baseline controller not platooning, where the exact fuel consumption improvement depends on the desired following distance. These results were also compared to a baseline that platooned over the entire route, providing evidence that there are situations where disengaging from a platoon is beneficial in the presence of heterogeneity.
Deep Reinforcement Learning for Adaptive Traffic Signal Control
Authors: Tan Kai Liang , Poddar Subhadipto , Sarkar Soumik , Sharma Anuj
Published: November 2019

Many existing traffic signal controllers are either simple adaptive controllers based on sensors placed around traffic intersections, or optimized by traffic engineers on a fixed schedule. Optimizing traffic controllers is time consuming and usually require experienced traffic engineers. Recent research has demonstrated the potential of using deep reinforcement learning (DRL) in this context. However, most of the studies do not consider realistic settings that could seamlessly transition into deployment. In this paper, we propose a DRL-based adaptive traffic signal control framework that explicitly considers realistic traffic scenarios, sensors, and physical constraints. In this framework, we also propose a novel reward function that shows significantly improved traffic performance compared to the typical baseline pre-timed and fully-actuated traffic signals controllers. The framework is implemented and validated on a simulation platform emulating real-life traffic scenarios and sensor data streams.
Delay-Dependent Output-Feedback Control for Blood Pressure Regulation Using LPV Techniques
Authors: Tasoujian Shahin , Grigoriadis Karolos , Franchek Matthew
Published: November 2019

This paper presents a delay-dependent parameter-varying control design approach to address the automated blood pressure regulation problem in the critical patient resuscitation using closed-loop administration of vasopressors. The mean arterial pressure (MAP) response of a patient subject to the intravenous vasoactive drug treatment is modeled as a linear parameter-varying (LPV) model, where varying model parameters and varying time-delay are considered as scheduling parameters of the system. Parameter-dependent Lyapunov-Krasovskii functionals are used to design an output-feedback dynamic controller to satisfy the closed-loop stability and reference MAP tracking requirements. The synthesis conditions are formulated in terms of Linear Matrix Inequalities (LMIs) that characterize the induced ℒ2-norm performance specification of the closed-loop system. The main objectives of the proposed control method in the presence of limitations posed by the time-varying model parameters and the large time-varying delay are to track the MAP reference command and maintain the blood pressure within the permissible range of commanded set-point, avoid undesirable overshoot and slow response, and to provide a smooth drug injection. Finally, to evaluate the performance of the proposed LPV blood pressure regulation approach, closed-loop simulations are conducted and the results confirm the effectiveness of the proposed control method against various simulated scenarios.
Model Predictive Control of Micro-CSP Integrated Into a Building HVAC System for Load Following Demand Response Programs
Authors: Toub Mohamed , Shahbakhti Mahdi , Robinett Rush D. , Aniba Ghassane
Published: November 2019

Building heat, ventilation and air conditioning (HVAC) systems are good candidates for demand response (DR) programs as they can flexibly alter their consumption to provide ancillary services to the grid and contribute to frequency and voltage regulation. One of the major ancillary services is the load following demand response (DR) program where the demand side tries to track a DR load profile required by the grid. This paper presents a real-time Model Predictive Control (MPC) framework for optimal operations of a micro-scale concentrated solar power (MicroCSP) system integrated into an office building HVAC system providing ancillary services to the grid. To decrease the energy cost of the building, the designed MPC exploits, along with the flexibility of the building’s HVAC system, the dispatching capabilities of the MicroCSP with thermal energy storage (TES) in order to control the power flow in the building and respond to the DR incentives sent by the grid. The results show the effect of incentives in the building participation to the load following DR program in the presence of a MicroCSP system and to what extent this participation is affected by seasonal weather variations and dynamic pricing.
Line-of-Sight Pure Pursuit Guidance Stability Analysis and Design Guideline for Car-Like Autonomous Ground Vehicles
Authors: Lin Letian , Zhu J. Jim
Published: November 2019

Pure pursuit guidance (PPG) has been used to solve the path following problem for car-like autonomous ground vehicles (CAGV). Most of the PPG guidance laws for CAGV guide the vehicle to follow a circular arc connecting the vehicle with a virtual target point on the path at a specified distance ahead of the vehicle, which could be called ARC PPG. Another type of PPG law for CAGV guides the vehicle by steering its velocity vector to align with the line-of-sight (LOS) connecting the vehicle and the virtual target. While some qualitative stability results exist on ARC PPG for some special types of curves of the path, such as straight and circular, a quantitative stability analysis on general paths is highly desirable but appears missing. Moreover, the existing guidance parameter selection methods depend highly on empirical tuning. In this work, the LOS PPG formulation is used to obtain a rigorous quantitative stability result stated as two theorems for general reference paths by treating the path curvature as a non-vanishing perturbation in a nonlinear context. The result shows that the ARC PPG is a special case of the LOS PPG, whereby establishing the generality of the theorems for PPG of CAGVs. Moreover, a geometric interpretation of the guidance parameters in relation to the path curvature is provided. By using the results of the stability analysis, a practical design guideline for LOS PPG is presented. Simulation results are shown to demonstrate the correctness of the stability analysis and the usefulness of the design guideline.
Towards Cooperative Transportation of Multiple Mecanum-Wheeled Automated Guided Vehicles
Authors: Peng Jih-Sien , Liu Yen-Chen
Published: November 2019

Utilizing multiple small-sized automated guided vehicles (AGVs) in cooperatively transport large and heavy objects in manufacturing factories or logistics is an emerging research direction. Flexibility and efficiency can be enhanced by using multi-AGV comparing to a large AGV with higher capacity especially in clutter environments. In this paper, a multi-AGV system by using Mecanum wheels to provide omnidirectional movement is proposed for cooperative transportation. Accordingly, the proposed Mecanum-wheeled automated guided vehicles (MWAGVs) composed of Mecanum wheels and a rotary platform provides not only non-constrained movement but also planar displacement for allowance of distance errors. In the proposed MWAGVs, the formation control with fixed geometry during operation is significant especially with unknown object information, dynamic uncertainties, and external disturbances. Therefore, the passivity-based adaptive synchronizing control algorithm is developed to ensure stability and tracking performance with uncertain dynamic parameters. Simulations and Experiments show the efficacy of designed Mecanum-wheeled AGV.
Experimental Validations on Vision-Based Path Tracking With Preview Four Wheel Steering Control
Authors: Peng Yansong , Wang Fengchen , Gurumoorthy Saikrishna , Chen Yan , Xin Mutian
Published: November 2019

In this paper, a vision-based path-tracking control strategy using four-wheel steering (4WS) is experimentally investigated via an automated ground vehicle (AGV). A low-cost monocular camera is used to continuously perceive the upcoming lane boundaries via capturing the preview road image frames. Based on the applied image processing algorithms, the vehicle lateral offset error with respect to the road center line and the heading angle error with respect to the road curvature are calculated in real time for the control purpose. The 4WS path-tracking controller is designed to minimize the two path-tracking errors of the AGV. The AGV with the 4WS system is utilized to perform the experimental tests on road to validate the path-tracking control design. For comparison, the road test is also conducted for the path-tracking control with only the front wheel steering. The experimental results show that the proposed 4WS is able to achieve better path-tracking performance.
Model Reference Control With Command Shaping for a Micro-Electromagnetic Actuator With Input Constraints
Authors: Eaglin Gerald , Vaughan Joshua
Published: November 2019

Model Reference Control is used to force a system to track the response of an assigned reference model, where the reference model is often designed to reflect the desired properties of the system. If a linear reference model is used, Model Reference Control has a linearizing effect for nonlinear plants, allowing it to be cascaded with linear controllers. Model Reference Control has been used to force nonlinear flexible systems to behave linearly such that input shaping can be used to limit residual vibration. However, when a system encounters saturation limits, the vibration limiting property of input shaping is degraded. This paper proposes Model Reference Control with an adaptive input shaping method to account for saturation by modifying the input shaper after saturation has been encountered. Simulations are presented to illustrate the effectiveness of this method in canceling residual vibration for a nonlinear electromagnetic actuator subject to input constraints.
Flight Dynamics and Control of a Farm of Tethered Energy Systems in a Turbulent Field
Authors: Siddiqui Ayaz , Ramaprabhu Praveen , Deese Joe , Vermillion Chris
Published: November 2019

In this paper, we present a combined flight dynamic, control system, and wake interaction model for an array (farm) of tethered energy systems, assessing the response of the array to a turbulent incoming flow field. The model presented herein constitutes the most detailed farm-level dynamic model for tethered energy systems to-date. In particular, the model accounts for more realistic approximations of tether dynamics and added mass effects, while characterizing the ability to control the system through both tethers and control surfaces. Focusing on a specific design and array geometry for ocean current energy harvesting, we analyze the dynamic performance of the array under a turbulent flow field that is representative of the turbulent environment in the Gulf Stream. We perform a frequency domain analysis of individual tethered systems in order to better understand the attenuation properties of the modeled system.
Path Following for the Soft Origami Crawling Robot
Authors: Angatkina Oyuna , Gustafson Kimberly , Wissa Aimy , Alleyne Andrew
Published: November 2019

Extensive growth of the soft robotics field has made possible the application of soft mobile robots for real world tasks such as search and rescue missions. Soft robots provide safer interactions with humans when compared to traditional rigid robots. Additionally, soft robots often contain more degrees of freedom than rigid ones, which can be beneficial for applications where increased mobility is needed. However, the limited number of studies for the autonomous navigation of soft robots currently restricts their application for missions such as search and rescue.

This paper presents a path following technique for a compliant origami crawling robot. The path following control adapts the well-known pure pursuit method to account for the geometric and mobility constraints of the robot. The robot motion is described by a kinematic model that transforms the outputs of the pure pursuit into the servo input rotations for the robot. This model consists of two integrated sub-models: a lumped kinematic model and a segmented kinematic model. The performance of the path following approach is demonstrated for a straight-line following simulation with initial offset. Finally, a feedback controller is designed to account for terrain or mission uncertainties.
Combining Reachability Analysis and Importance Sampling for Accelerated Evaluation of Highly Automated Vehicles at Pedestrian Crossing
Authors: Wang Xinpeng , Peng Huei , Zhao Ding
Published: November 2019

Publisher’s Note:

This paper was selected for publication in ASME Letters in Dynamic Systems and Control.

https://www.asmedigitalcollection.asme.org/lettersdynsys/article/doi/10.1115/1.4046610/1075844/Combining-Reachability-Analysis-and-Importance
Dynamic Control of Soft Robots Using Reinforcement Learning
Authors: Pawlowski Ben , Anderson Charles W. , Zhao Jianguo
Published: November 2019

Soft robots made from soft materials recently attracted tremendous research owing to their unique softness compared with rigid robots, making them suitable for applications such as manipulation and locomotion. However, also due to their softness, the modeling and control of soft robots present a significant challenge because of the infinite degree of freedom. In this case, although analytic solutions can be derived for control, they are too computationally intensive for real-time application. In this paper, we aim to leverage reinforcement learning to approach the control problem. We gradually increase the complexity of the control problems to learn. We also test the effectiveness and efficiency of reinforcement learning techniques to the control of soft robots for different tasks. Simulation results show that the control commands to be computed in milliseconds, allowing effective control of soft manipulators, up to trajectory tracking.
Safe, Aggressive Quadrotor Flight via Reachability-Based Trajectory Design
Authors: Kousik Shreyas , Holmes Patrick , Vasudevan Ram
Published: November 2019

Quadrotors can provide services such as infrastructure inspection and search-and-rescue, which require operating autonomously in cluttered environments. Autonomy is typically achieved with receding-horizon planning, where a short plan is executed while a new one is computed, because sensors receive limited information at any time. To ensure safety and prevent robot loss, plans must be verified as collision free despite uncertainty (e.g, tracking error). Existing spline-based planners dilate obstacles uniformly to compensate for uncertainty, which can be conservative. On the other hand, reachability-based planners can include trajectory-dependent uncertainty as a function of the planned trajectory. This work applies Reachability-based Trajectory Design (RTD) to plan quadrotor trajectories that are safe despite trajectory-dependent tracking error. This is achieved by using zonotopes in a novel way for online planning. Simulations show aggressive flight up to 5 m/s with zero crashes in 500 cluttered, randomized environments.
Switched Linear Model of a Stratified Hot Water Tank for Control of Micro-CHP Systems
Authors: Bird Trevor , Weaver Catherine , Jain Neera
Published: November 2019

We present a switched linear system approach for modeling the complex nonlinear dynamics associated with temperature inversion occurring in thermally stratified hot water tanks. Such tanks are commonly used for thermal energy storage, particularly in low- to medium-temperature waste heat recovery applications. By separating the influence of temperature inversion from the internal heat transfer between states in the governing differential equations, we paramaterize the nonlinearity using a vector of discrete variables. This vector is then used to define the switching between a set of linear, discrete time models. The proposed switched model is validated against a reduced-order nonlinear model of the thermal energy storage and then integrated with a fuel cell model to capture the dynamics of a micro-combined heat and power system. Simulation results demonstrate the importance that temperature inversion has on the stratification dynamics which in turn has implications for control of such systems.
On Receding Horizon Chance Constraint Motion Planning for Uncertain Multi-Agent Systems
Authors: Bagla Yash , Srivastava Vaibhav
Published: November 2019

We propose and study a motion planning algorithm for multi-agent autonomous systems to navigate through uncertain and dynamic environments. We use a receding horizon chance constraint framework that allows for tuning the trade-off between the risk of collision and the infeasibility of paths. We consider sampling-based incremental planning algorithms and extend them to the case of multiple agents and dynamic and uncertain environments. The receding horizon control framework is used to incorporate sensor measurements at a fixed interval of time to reduce uncertainty about agents’ state and environment. Our presentation focuses on rapidly-exploring random trees (RRTs) and the assumption of Gaussian noise in the uncertainty model. Our algorithm is illustrated using several examples.
Imaging and Studying Standing Waves with a Homemade Melde-type Apparatus and Information and Communication Technology (ICT)
Authors: Bozzo G. , de Sabata F. , Pistori S. , Monti F.
Published: November 2019

Wave physics phenomena can be observed in everyday life and represent a fundamental prerequisite to many domains of classical and modern physics. Lots of studies demonstrate that novices have to face important learning difficulties in approaching this topic. The study of string vibrations’ modes allows an educational introduction to basic concepts, but common laboratory approaches employ dedicated experimental setups usually requiring some expensive components (wave or vibration generators, motion detectors) that often are not present in school laboratories. The problem of low-cost solutions for the Melde apparatus has been addressed many years ago. Some recent papers propose low-cost solutions in which standing waves on a Slinky spring obtained with non-reproducible hand movements are analyzed by means of video analysis software. In this context, we projected a modern revisitation of the historical experiment proposed for the first time by Melde in 1859, employing low-cost materials and commonly used information and communication technology (ICT) devices in order to generate and analyze standing waves on a string (see next section). This experimental setup was proposed to a group of 26 students (17–18 years old) in the fourth year of an Italian high school. Students were involved in four sessions (about four hours each) of inquiry-based laboratorial activities, in which they recorded various standing wave configurations on a string with their smartphones and analyzed the obtained videos using the freeware Tracker®, whose potential value is well known in literature. The experimental setup is described and an example of data analysis and obtained results is shown. Finally, students were asked to develop their own Melde-type apparatus; in the last section we present a very interesting alternative solution developed by a group of them, which offers almost the same educational features on a reduced scale using even simpler components.
Applying Structural Mathematics in Physics: Case of Parallel Connection
Authors: Sokolowski Andrzej
Published: November 2019

Research identifies two domains by which mathematics allows learning physics concepts: a technical domain that includes algorithmic operations that lead to solving formulas for an unknown quantity and a structural domain that allows for applying mathematical knowledge for structuring physical phenomena. While the technical domain requires employing only students’ technical skills, the structural domain requires activating students’ algebraic reasoning and applying it to learn more about physical systems beyond evaluating formulas. Students’ technical skills in mathematics do not convert into structural skills automatically, and this is perceived as an obstacle that prevents complete appreciation of physics knowledge. There can be various ways to activate or to develop students’ mathematical structural domain in physics. Most common are: (a) mathematical modeling that involves experimental activities concluding with algebraic relations; (b) stimulating students to work with symbols in limiting situations; or (c) developing the understanding of physics formulas (e.g., see Ref. 5). While all these methods are valuable, students still face difficulties with transferring their structural math skills to physics, thus new attempts are made. The process of developing students’ algebraic structural skills proposed in this paper is a combination of the current approaches; however, as a means of developing mathematical reasoning, a mathematical structure is used that is derived from a physics formula. More specifically, this paper presents an attempt to interpret formula for the equivalent resistance of a parallel electric circuit using the properties of a rational function. Such formulated aim reflects not only recommendations of the physics education research community but also mathematics because it guides students in how to merge mathematical knowledge with the behavior of a physical system to learn more about the system.
Exploring Magnetic Resonance with a Compass
Authors: Cookson Esther , Nelson David , Anderson Michael , McKinney Daniel L. , Barsukov Igor
Published: November 2019

Magnetic resonance is a quantum phenomenon and describes a resonant interaction of spins with electromagnetic fields. Its understanding requires advanced knowledge of quantum mechanics and condensed matter physics and thus often remains elusive to students. However, the great impact of this phenomenon on medicine, science, and technology makes magnetic resonance an important subject for general education, and it requires a graspable model for translating the physical concepts without resorting to advanced physics. One of the most common and familiar objects related to magnetism is the compass. Here, we develop an inexpensive tabletop demonstration experiment for magnetic resonance. The compass is placed into the magnetic field of a permanent magnet (strong refrigerator magnet); an alternating field of an electromagnetic coil (solenoid) excites a resonant oscillation of the compass needle. The experiment has been proven to catch the attention of audiences of all ages.
Making Future Researchers: Internship Opportunities for Physics Students
Authors: Lincoln Don , Pasero Spencer , Thompson Rebecca
Published: November 2019

While the majority of students that pursue a physics education learn mostly in a classroom setting, hands-on experiences can take their appreciation of physics to the next level. Summer internships offer just that, hands-on learning experiences and a taste of what a career in physics is really like. Many research-oriented institutions offer summer internship experiences for students at all levels, from high school through graduate school. The experience and connections made during these summer programs can be transformative to a student’s career and science identity.
Bold plan to retrieve Mars samples takes shape
Authors: Clery Daniel , Voosen Paul
Published: November 2019

NASA and Europe settle on suite of missions to bring back rocks from the Red Planet.
Researchers sound alarm on European data law
Authors: Rabesandratana Tania
Published: November 2019

Privacy regulations impede international studies on diabetes and Alzheimer's disease.
Trash, treasure, and everything in between
Secondhand: Travels in the New Global Garage Sale
Adam Minter
Bloomsbury, 2019. 320 pp.
Authors: Dooley Kevin
Published: November 2019

A journalist traces the evolution of the large, but largely unknown, global secondhand market
How low should we go when warning for earthquakes?
Authors: Cochran Elizabeth S. , Husker Allen L.
Published: November 2019

Social responses to alerts are critical but understudied
Viral Determinants in H5N1 Influenza A Virus Enable Productive Infection of HeLa Cells
Authors: Rodriguez-Frandsen Ariel , Martin-Sancho Laura , Gounder Anshu P. , Chang Max W. , Liu Wen-Chun , De Jesus Paul D. , von Recum-Knepper Jessica , Dutra Miriam S. , Huffmaster Nicholas J. , Chavarria Monica , Mena Ignacio , Riva Laura , Nguyen Courtney B. , Dobariya Saunil , Herbert Kristina M. , Benner Christopher , Albrecht Randy A. , García-Sastre Adolfo , Chanda Sumit K.
Published: November 2019

Many zoonotic avian influenza A viruses have successfully crossed the species barrier and caused mild to life-threatening disease in humans. While human-to-human transmission is limited, there is a risk that these zoonotic viruses may acquire adaptive mutations enabling them to propagate efficiently and cause devastating human pandemics. Therefore, it is important to identify viral determinants that provide these viruses with a replicative advantage in human cells. Here, we tested the growth of influenza A virus in a subset of human cell lines and found that abortive replication of H1N1 viruses in HeLa cells can be circumvented upon the introduction of H5N1 virus HA and NP. Overall, this work leverages the genetic diversity of multiple human cell lines to highlight viral determinants that could contribute to H5N1 virus pathogenesis and tropism.
Complete Genome Sequence of Rhodococcus erythropolis X5, a Psychrotrophic Hydrocarbon-Degrading Biosurfactant-Producing Bacterium
Authors: Delegan Yanina , Valentovich Leonid , Petrikov Kirill , Vetrova Anna , Akhremchuk Artur , Akimov Vladimir
Published: November 2019

Rhodococcus erythropolis
X5 is a psychrotrophic (cold-adapted) hydrocarbon-degrading bacterium, as it showed effective
n
-alkane destruction at low positive temperatures. Here, the genome of strain X5 was completely sequenced; it consists of a 6,472,161-bp circular chromosome (62.25% GC content) and a 526,979-bp linear plasmid, pRhX5-526k (62.37% GC content).
Double trouble: ciclosporin–simvastatin coinduced rhabdomyolysis
Authors: Hafouda Yakeen , Sharma Abhishek , Li Vincent , Yesudian Paul Devakar
Published: November 2019

A 73-year-old woman presented with an acute exacerbation of her long-standing psoriasis. Ciclosporin was commenced due to the severity of her symptoms resulting in remission within 2 weeks. Full blood count, urea and electrolytes following initiation of treatment were unremarkable, although she complained of muscle aches, which was attributed to her known multiple sclerosis. Three weeks later she was admitted to the hospital with diarrhoea and vomiting. Repeat blood tests revealed raised creatinine (528 μmol/L (normal range (NR) n=45–84 μmol/L)), urea (32.6 mmol/L (NR 2.5–7.8 mmol/L)) and creatine kinase (6792 IU/L (NR 25–200 IU/L)) levels and reduced estimated glomerular filtration rate of 7. A diagnosis of acute kidney injury secondary to rhabdomyolysis was made due to an interaction between ciclosporin and simvastatin, precipitated by the dehydration from gastroenteritis. Haemofiltration was required to stabilise her renal function and she made a complete recovery.
Degloving injury to groin, scrotum and penis due to low-velocity handlebar injury
Authors: Thompson Hannah , Burdall Oliver , Lakhoo Kokila
Published: November 2019

Bicycles are a common cause of blunt abdominal trauma causing 5%–14% of injuries. However, impalement or shear injuries from low-velocity mechanism of injury are rare. We report a case of a 14-year-old boy presenting with an extensive left groin injury sustained while cycling one-handed along the pavement at walking pace. The laceration ran for 12–14 cm from the left groin across the pubis to the right and 10 cm inferiorly into the perineum. This inverted the left scrotum and partially degloved the penis. The corpus cavernosa and tunica vaginalis were exposed up to the level of the superficial inguinal ring. Literature on handlebar-impalement injuries is sparse and the majority of penile degloving injuries described in the literature result from alternative mechanisms. This unusual case demonstrates the potential forces involved, and potential damage resulting from handlebar injuries even at low velocity.
Small bowel perforation secondary to CMV-positive terminal ileitis postrenal transplant
Authors: Kato Kosuke , Cooper Michelle
Published: November 2019

Cytomegalovirus (CMV) infection of the gastrointestinal tract is common in immunosuppressed patients; however, small bowel perforation from tissue-invasive CMV disease after many years of immunosuppressive therapy is a rare complication requiring timely medical and surgical intervention. We report a case of a postrenal transplant patient who presented to the emergency department with severe lower abdominal pain with CT of the abdomen/pelvis revealing a small bowel perforation. He underwent an emergent laparoscopic right hemicolectomy, and his histopathology of the terminal ileum was positive for CMV disease. He was successfully treated with intravenous ganciclovir postoperatively. We discuss the pathophysiology, histopathological features and treatment of CMV infection.
Metabolic encephalopathy caused by nitrous oxide (‘laughing gas’) induced hyperammonaemia
Authors: Vive Marissa Ginette Danielle , Anguelova Galia Valentinova , Duim Sjoerd , Hofstee Herman Marcel André
Published: November 2019

A 26-year-old man presented at the emergency department with confusion and decreased consciousness after several days of vomiting. In the preceding 6 months, he had used a 2-litre tank of nitrous oxide (N2O) weekly. His metabolic encephalopathy was caused by hyperammonaemia which probably resulted from interference of N2O-induced vitamin B12deficiency with ammonia degradation. A catabolic state might have contributed to the hyperammonaemia in this case. After treatment with vitamin B12and lactulose, both his consciousness and hyperammonaemia improved. He reported no residual complaints after 3 months of follow-up. Since N2O is increasingly used as a recreational drug, we recommend considering hyperammonaemia as a cause of metabolic encephalopathy in cases of N2O use and altered mental status.
Central airway compression by massively dilated pulmonary artery in a patient with pulmonary arterial hypertension: a rare entity
Authors: Saha Biplab Kumar , Beegle Scott
Published: November 2019

Patients with pulmonary arterial hypertension (PAH) usually die from progressive right ventricular failure. Mechanical complications due to pulmonary artery (PA) enlargement are rare and include tracheobronchial and left main coronary artery compression, and PA dissection. A 62-year-old female with PAH was seen in our office for follow-up. During the evaluation, spirometry was performed, which revealed a severe obstructive ventilatory limitation. Subsequent workup identified compression of bilateral mainstem bronchi from the dilated PA as the aetiology for the abnormal spirometry. Very few cases of this rare complication have been reported in the literature. A significant dilation of the PA is necessary (>4 cm) for the occurrence of these complications. Dilation of PA is an independent risk factor for sudden unexpected death in patients with PAH.
Regional multidisciplinary team intervention programme to improve colorectal cancer outcomes: study protocol for the Yorkshire Cancer Research Bowel Cancer Improvement Programme (YCR BCIP)
Authors: Taylor John , Wright Penny , Rossington Hannah , Mara Jackie , Glover Amy , West Nick , Morris Eva , Quirke Phillip
Published: November 2019

Introduction

Although colorectal cancer outcomes in England are improving, they remain poorer than many comparable countries. Yorkshire Cancer Research has, therefore, established a Bowel Cancer Improvement Programme (YCR BCIP) to improve colorectal cancer outcomes within Yorkshire and Humber, a region representative of the nation. It aims to do this by quantifying variation in practice, engaging with the colorectal multidisciplinary teams (MDTs) to understand this and developing educational interventions to minimise it and improve outcomes.

Methods and analysis

Initially, routine health datasets will be used to quantify variation in the demographics, management and outcomes of patients across the Yorkshire and Humber region and results presented to MDTs. The YCR BCIP is seeking to supplement these existing data with patient-reported health-related quality of life information (patient-reported outcome measures, PROMs) and tissue sample analysis. Specialty groups (surgery, radiology, pathology, clinical oncology, medical oncology, clinical nurse specialists and anaesthetics) have been established to provide oversight and direction for their clinical area within the programme, to review data and analysis and to develop appropriate educational initiatives.

Ethics and dissemination

The YCR BCIP is aiming to address the variation in practice to significantly improve colorectal cancer outcomes across the Yorkshire and Humber region. PROMs and tissue sample collection and analysis will help to capture the information required to fully assess care in the region. Engagement of the region’s MDTs with their data will lead to a range of educational initiatives, studies and clinical audits that aim to optimise practice across the region.
Integrating quantitative and qualitative data and findings when undertaking randomised controlled trials
Authors: Richards David A , Bazeley Patricia , Borglin Gunilla , Craig Peter , Emsley Richard , Frost Julia , Hill Jacqueline , Horwood Jeremy , Hutchings Hayley Anne , Jinks Clare , Montgomery Alan , Moore Graham , Plano Clark Vicki L , Tonkin-Crine Sarah , Wade Julia , Warren Fiona C , Wyke Sally , Young Bridget , O"Cathain Alicia
Published: November 2019

It is common to undertake qualitative research alongside randomised controlled trials (RCTs) when evaluating complex interventions. Researchers tend to analyse these datasets one by one and then consider their findings separately within the discussion section of the final report, rarely integrating quantitative and qualitative data or findings, and missing opportunities to combine data in order to add rigour, enabling thorough and more complete analysis, provide credibility to results, and generate further important insights about the intervention under evaluation. This paper reports on a 2 day expert meeting funded by the United Kingdom Medical Research Council Hubs for Trials Methodology Research with the aims to identify current strengths and weaknesses in the integration of quantitative and qualitative methods in clinical trials, establish the next steps required to provide the trials community with guidance on the integration of mixed methods in RCTs and set-up a network of individuals, groups and organisations willing to collaborate on related methodological activity. We summarise integration techniques and go beyond previous publications by highlighting the potential value of integration using three examples that are specific to RCTs. We suggest that applying mixed methods integration techniques to data or findings from studies involving both RCTs and qualitative research can yield insights that might be useful for understanding variation in outcomes, the mechanism by which interventions have an impact, and identifying ways of tailoring therapy to patient preference and type. Given a general lack of examples and knowledge of these techniques, researchers and funders will need future guidance on how to undertake and appraise them.
Do BRCA1 and BRCA2 gene mutation carriers have a reduced ovarian reserve? Protocol for a prospective observational study
Authors: Winship Amy Louise , Willson Chris , Hansen Karl R , Hutt Karla J , Hickey Martha
Published: November 2019

Introduction

BRCA1/2 gene mutations increase risk of breast and/or ovarian cancer and may have implications for reproductive health. Indirect biomarkers of the ovarian primordial follicle pool (anti-Müllerian hormone (AMH)) and one small study in female cadavers suggest that ovarian reserve may be reduced in BRCA mutation carriers, but findings are conflicting and association between circulating AMH and primordial follicle number is not established. The aim of this study is to measure primordial follicle density in premenopausal ovarian tissue samples from women with BRCA1/2 gene mutations versus age-matched comparison group.

Methods and analysis

Prospective observational study measuring associations between BRCA gene mutation status, premenopausal ovarian primordial follicle density and serum AMH concentrations versus age-matched premenopausal women from the general population. Primordial follicle density will be measured in cortical sections from ovarian tissue collected at the time of risk-reducing bilateral salpingo-oophorectomy (RRBSO) in 88 BRCA1 gene mutation carriers, 65 BRCA2 gene mutation carriers and 157 non-mutation carriers. Primordial follicle density will be determined by counting follicles in a known volume of ovarian cortical tissue using light microscopy. Follicles will be identified by immunohistochemical staining for oocyte marker mouse vasa homologue. To inform the mechanisms underlying reduced ovarian reserve, the proportion of follicles containing oocytes with DNA damage will be determined by immunohistochemical staining for phosphorylated histone H2AX and terminal deoxynucleotidyl transferase dUTP nick end labelling assay to identify apoptotic cells. Follicle density will be correlated with circulating AMH concentrations quantified in the same cohort, using an electrochemiluminescence immunoassay on an automated platform.

Ethics and dissemination

Ethics approval has been granted by Peter MacCallum Cancer Centre to access biobanks, including; The Kathleen Cuningham Foundation Consortium for Research into Familial Breast Cancer (kConFab-HREC#97_27) and the What Happens after Menopause? (HREC12PMCC24-12/90) and Melbourne IVF.
Psychometric properties of the global rating of change scales in patients with neck disorders: a systematic review with meta-analysis and meta-regression
Authors: Bobos Pavlos , MacDermid Joy , Nazari Goris , Furtado Rochelle
Published: November 2019

Objective

The purpose of this systematic review was to critically appraise and synthesise the psychometric properties of Global Rating of Change (GROC) scales for assessment of patients with neck pain.

Design

Systematic review.

Data sources

A search was performed in four databases (MEDLINE, EMBASE, CINAHL, SCOPUS) until February 2019.

Data extraction and synthesis

Eligible articles were appraised using Consensus-based Standards for the selection of health Measurement Instruments checklist and the Quality Appraisal for Clinical Measurement Research Reports Evaluation Form.

Results

The search obtained 16 eligible studies and included in total 1533 patients with neck pain. Test–retest reliability of global perceived effect (GPE) was very high (intraclass correlation coefficient=0.80 to 0.92) for patients with whiplash. Pooled data of Pearson’s r indicated that GROC scores were moderately correlated with neck disability change scores (0.53, 95% CI: 0.47 to 0.59). Pooled data of Spearman’s correlations indicated that GROC scores were moderately correlated with neck disability change scores (0.56, 95% CI: 0.41 to 0.68).

Conclusions

This study found excellent quality evidence of very good-to-excellent test–retest reliability of GPE for patients with whiplash-associated disorders. Evidence from very good-to-excellent quality studies found that GROC scores are moderately correlated to an external criterion patient-reported outcome measure evaluated pre-post treatment in patients with neck pain. No studies were found that addressed the optimal form of GROC scales for patients with neck disorders or compared the GROC to other options for single-item global assessment.

PROSPERO registration number

CRD42018117874.