bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Electromechanical Coupling on Locally Resonant Metastructures for Simultaneous Energy Harvesting and Vibration Attenuation Applications
Authors: Bukhari Mohammad A. , Qian Feng , Barry Oumar R. , Zuo Lei
Published: January 2021

The study of simultaneous energy harvesting and vibration attenuation has recently been the focus in many acoustic meta-materials investigations. The studies have reported the possibility of harvesting electric power using electromechanical coupling; however, the effect of the electromechanical resonator on the obtained bandgap’s boundaries has not been explored yet. In this paper, we investigate metamaterial coupled to electromechanical resonators to demonstrate the effect of electromechanical coupling on the wave propagation analytically and experimentally. The electromechanical resonator is shunted to an external load resistor to harvest energy. We derive the analytical dispersion curve of the system and show the band structure for different load resistors and electromechanical coupling coefficients. To verify the analytical dispersion relations, we also simulate the system numerically. Furthermore, experiment is carried out to validate the analytical observations. The obtained observations can guide designers in selecting electromechanical resonator parameters for effective energy harvesting from meta-materials.
Formation Control for Underactuated Surface Vessel Networks
Authors: Wang Bo , Nersesov Sergey , Ashrafiuon Hashem
Published: January 2021

Developing distributed control algorithms for multi-agent systems is difficult when each agent is modeled as a nonlinear dynamical system. Moreover, the problem becomes far more complex if the agents do not have sufficient number of actuators to track any arbitrary trajectory. In this paper, we present the first fully decentralized approach to formation control for networks of underactuated surface vessels. The vessels are modeled as three degree of freedom planar rigid bodies with two actuators. Algebraic graph theory is used to model the network as a directed graph and employing a leader-follower model. We take advantage of the cascade structure of the combined nonlinear kinematic and dynamic model of surface vessels and develop a reduced-order error dynamic model using a state transformation definition. The error dynamics and consequently all system states are then stabilized using sliding mode control approach. It is shown that the stabilization of the reduced-order error dynamics guarantees uniform global asymptotic stability of the closed-loop system subject to bounded uncertainties. The proposed control method can be implemented in directed time-invariant communication networks without the availability of global position measurements for any of the vehicles participating in the network. An example of a a network of five surface vessels is simulated to verify the effective performance of the proposed control approach.
Energy-Optimal, Direct-Phase Control of Brushless Motors for Robotic Drives
Authors: Ghorbanpour Amin , Richter Hanz
Published: January 2021

In this work, simultaneous energy regeneration and motion control for robot manipulators with brushless direct current (BLDC) motors is considered. All joints of the robot are connected to regenerative drives powered from a single ultra-capacitor. A new voltage-based control method is developed to individually command each phase of the BLDC motor. Three independent regenerative drives are interconnected in a wye configuration, and each drives a phase of the motor. The objective is to determine the control inputs for each drive to minimize energy consumption from the ultra-capacitor for a given motion task. To this end, the problem is formulated as constrained quadratic optimization problem that gives the control inputs based on the desired torque generated by a virtual controller. An experimental evaluation is performed using a pendulum actuated by a BLDC motor. It is shown that the suggested control method can accomplish the motion task and it is capable of energy regeneration. The results show a reduction of about 40% in energy consumption for the condition of the study, relative to non-regenerative case.
Cooperative Localization of Vehicles in Three-Dimensional Space
Authors: Oliveros Juan Carlos , Ashrafiuon Hashem
Published: January 2021

Effective trajectory planning and cooperative control of multi-agent systems require accurate localization of the agents to perform collaborative missions. Accurate localization may be achieved by Global Positioning System (GPS) and simultaneous localization and mapping. However, GPS signals and fixed features may not be readily available, particularly in remote and unstructured environments. Under these circumstances, Cooperative Localization (CL) has been proposed as a short-term solution that can significantly improve vehicle pose estimation. CL algorithms have been developed and tested mainly on mobile robots and planar vehicles due to complexities of three-dimensional (3D) motion. In this paper, we present a CL algorithm for multi-agent systems comprised of 3D vehicles. Each vehicle’s pose is represented by three position and three orientation variables. Quaternions are employed to represent orientation and avoid singularities associated with Euler angle. Vehicle kinematic velocity relations are used to model vehicle dynamics with respect to a fixed reference frame. It is assumed a vehicle can take relative pose measurements of other neighboring vehicles within an ad hoc network of agents. We then designate the observed as target vehicles and the observers as base vehicles and determine the linearized output matrix of the relative measurements for Extended Kalman Filter (EKF) application. Simulations are presented to discuss the advantages and shortcomings of the algorithm.
A Switched Adaptive Model for Layer-to-Layer Selective Laser Melting With Varying Laser Paths
Authors: Wang Xin , Bristow Douglas A. , Landers Robert G.
Published: January 2021

Selective Laser Melting (SLM) is an additive manufacturing technique that uses a moving laser source to melt and solidify an area of a powder bed by scanning over the area with a laser beam, thus, fabricating a solid part layer by layer. Although SLM can print complex geometries that are difficult to achieve by machining, quality and repeatability of a printed part are still two challenges that must be addressed. These challenges arise due to the complex physical transformation of the metal powder and the lack of mature process control schemes.

Researchers often use optical sensors for the feedback control of SLM processes. Since fast motion of laser beams may not allow real time feedback control given the large quantity of data to be processed, some researchers have applied layer-to-layer control, i.e., collecting data during the fabrication of an entire layer and then updating process parameter profiles for the next layer. In this paper, by specifying the input and output as laser power and peak temperature, a parameter adaption model is used to estimate the unknown input-output model, which is difficult to evaluate analytically due to complex process physics. In addition, laser paths in SLM usually vary to create more isotropic parts than can be achieved with constant laser paths. The variation of laser paths results in varying local thermal histories. To handle the common situation where laser paths are varying from layer to layer, a switched model is designed and trained by a Parameter Adaption Algorithm (PAA). In a simulation of an overhang part with a constant cross-section and varying laser paths, the switched adaptive model shows the ability to achieve a desired output profile and also better performance if more switched gains are utilized.
Modeling and Simulation of Aircell Actuator Seat Cushion With Pneumatic Line Lag and Capacitative Effects
Authors: Nuthi Pavan , Wijesundara Muthu B. J.
Published: January 2021

This article presents the development of a hybrid model with pneumatic lag effects for the smart seat cushion which can be extended to any active aircell cushion. Smart seat cushion is one such rehabilitation device which reduces the risk of pressure injury formation by automatically performing repositioning exercises for wheelchair users. Operation of the smart seat cushion device can be greatly enhanced by accurate prediction of pneumatic line lag during its various modes of operation. The proposed model combines a linear model from literature to capture the effects of pneumatic line lag and a bang-bang scheduling controller to enable efficient use of pneumatic components in the smart seat cushion device. The resulting simulation is validated by conducting multiple runs of uniform inflation experiment with the device, and comparing the closed loop behavior of the model. The hybrid modeling allows accurate prediction of pneumatic line lag in the smart seat cushion during various modes of redistribution and offloading. The modeling accuracy and the prediction of switching times for discrete states can be improved by data sampled at a higher rate from the device.
On the Ergodicity of an Autonomous Robot for Efficient Environment Explorations
Authors: Kabir Rabiul Hasan , Lee Kooktae
Published: January 2021

This paper addresses the autonomous robot ergodicity problem for efficient environment exploration. The spatial distribution as a reference distribution is given by a mixture of Gaussian and the mass generation of the robot is assumed to be skinny Gaussian. The main problem to solve is then to find out proper timing for the robot to visit as well as leave each component-wise Gaussian for the purpose of achieving the ergodicity. The novelty of the proposed method is that no approximation is required for the developed method. Given the definition of the ergodic function, a convergence condition is derived based on the timing analysis. Also, a formal algorithm to achieve the ergodicity is provided. To support the validity of the proposed algorithm, simulation results are provided.
Optimal Path Planning for a Team of Heterogeneous Drones to Monitor Agricultural Fields
Authors: Faryadi Saba , Davoodi Mohammadreza , Mohammadpour Velni Javad
Published: January 2021

In this work, we investigate the problem of finding the minimum coverage time of an agricultural field using a team of heterogeneous unmanned aerial vehicles (UAVs). The aerial robotic system is assumed to be heterogeneous in terms of the equipped cameras’ field of view, flight speed, and battery capacity. The coverage problem is formulated as a vehicle routing problem (VRP) [1] with two significant extensions. First, the field is converted into a graph, including nodes and edges generated based on sweep direction and the minimum length of UAVs’ footprints. Second, the underlying optimization problem accounts for aerial vehicles having different sensor footprints. A series of simulation experiments are carried out to demonstrate that the proposed strategy can yield a satisfactory monitoring performance and offer promise to be used in practice.
Mobile Sensing of Multi-Dimensional Dynamic Field via Compressed Sensing
Authors: Li Tianwei , Zou Qingze
Published: January 2021

In this paper, we consider to measure time-varying dynamic signals at discrete locations by using a single mobile sensor The challenge arises as the mobile sensor is required to transit between the sampling locations, resulting in intermittent measurements at each location, and the time-varying dynamic signals must be recovered from the intermittent measured data. In this work, we propose to tackle this single mobile sensing of multi-location dynamic signals through the compressed sensing framework. Both the temporal-spatial coupling arising from the random sampling requirement and the mobility limitation of the sensor in transition between sampling locations are addressed through a simulated annealing based optimization approach. Simulation results are presented and discussed to illustrate the proposed method.
Model-Based Dynamic In-Cylinder Air Charge, Residual Gas and Temperature Estimation for a GDI Spark Ignition Engine Using Cylinder, Intake and Exhaust Pressures
Authors: Khameneian Amir , Wang Xin , Dice Paul , Shahbakhti Mahdi , Naber Jefferey D. , Archer Chad , Moilanen Peter , Glugla Chris , Huberts Garlan
Published: January 2021

The in-cylinder trapped air, residual gas, and temperature directly impact Spark Ignition (SI) engine operation and control. However, estimation of these variables dynamically is difficult. This study proposes a dynamic cycle-by-cycle model for estimation of the in-cylinder mixture temperature at different events such as Intake Valve Closed (IVC), as well as mass of trapped air and residual gas. In-cylinder, intake and exhaust pressure traces are the primary inputs to the model. The mass of trapped residual gas is affected by valve overlap increase due to the exhaust gas backflow. Of importance to engines with Variable Valve Timing (VVT), the compressible ideal-gas flow correlations were applied to predict the exhaust gas backflow into the cylinder. Furthermore, 1D GT-Power Three Pressure Analysis (TPA) was used to calibrate and validate the designed model under steady-state conditions. To minimize the calibration efforts, Design of Experiments (DOE) analysis methodology was used. The transient behavior of the model was validated using dynamometer dynamic driving cycle. The cycle-based output parameters of the developed model are in good agreement with transient experimental data with minimal delay and overshoot. The predicted parameters follow the input dynamics propagated in the in-cylinder, intake and exhaust pressure traces with a 1.5% average relative steady-state prediction error.
Data-Driven Drop Formation Modeling in Nanoliter Drop-on-Demand Inkjet Printing
Authors: Wang Jie , Chiu George T.-C.
Published: January 2021

Drop formation models are essential for the control of drop-on-demand (DoD) inkjet printing process. Traditional numerical models are difficult to implement in real-time control. In this paper, an equivalent circuit model (ECM) is developed to motivate the implementation of a data-driven ARX model combined with a drop volume adjuster to estimate drop volume. Drop pinch-off instants and drop velocities are modeled in polynomials with respect to the parameters of the drive waveform. All models are validated through 10-fold cross validation. The simulation of the drop volume model shows good agreement with experimental results.
Dynamic Modeling of a Steerable Drifter
Authors: Gaskell Eric , Tan Xiaobo
Published: January 2021

Drifters are energy-efficient platforms for monitoring rivers and oceans. Prior work largely focused on free-floating drifters that drift passively with flow and have little or no controllability. In this paper we propose steerable drifters that use multiple rudders for modulating the hydrodynamic forces and thus maneuvering. A dynamic model for drifters with multiple rudders is presented. Simulation is conducted to examine the behavior of the drifter in two different flow conditions, uniform flow and parabolic flow. When there is no difference in relative flow between the rudders, as in uniform flow, the drifter can only be controlled until its velocity approaches that of the water. However, when present, local flow differentials can be exploited to initiate motion lateral to the ambient flow and control the trajectory of the drifter to some degree. The motion of the drifter is further classified as belonging to one of three major modes, rotational, oscillatory, and stable. The behavior of the drifter in a simulated river was mapped for different rudder angles. Identifying the parameters that induce each mode lays the groundwork for developing a feedback control scheme for the drifter.
Leveraging Conventional Control to Improve Performance of Systems Using Reinforcement Learning
Authors: Eaglin Gerald , Vaughan Joshua
Published: January 2021

While many model-based methods have been proposed for optimal control, it is often difficult to generate model-based optimal controllers for nonlinear systems. One model-free method to solve for optimal control policies is reinforcement learning. Reinforcement learning iteratively trains an agent to optimize a reward function. However, agents often perform poorly at the beginning of training and require a large number of trials to converge to a successful policy. A method is proposed to incorporate domain knowledge of dynamics and control into the controllers using reinforcement learning to reduce the training time needed. Simulations are presented to compare the performance of agents utilizing domain knowledge to those that do not use domain knowledge. The results show that the agents with domain knowledge can accomplish the desired task with less training time than those without domain knowledge.
Developmental Reinforcement Learning of Control Policy of a Quadcopter UAV With Thrust Vectoring Rotors
Authors: Deshpande Aditya M. , Kumar Rumit , Minai Ali A. , Kumar Manish
Published: January 2021

In this paper, we present a novel developmental reinforcement learning-based controller for a quadcopter with thrust vectoring capabilities. This multirotor UAV design has tilt-enabled rotors. It utilizes the rotor force magnitude and direction to achieve the desired state during flight. The control policy of this robot is learned using the policy transfer from the learned controller of the quadcopter (comparatively simple UAV design without thrust vectoring). This approach allows learning a control policy for systems with multiple inputs and multiple outputs. The performance of the learned policy is evaluated by physics-based simulations for the tasks of hovering and way-point navigation. The flight simulations utilize a flight controller based on reinforcement learning without any additional PID components. The results show faster learning with the presented approach as opposed to learning the control policy from scratch for this new UAV design created by modifications in a conventional quadcopter, i.e., the addition of more degrees of freedom (4-actuators in conventional quadcopter to 8-actuators in tilt-rotor quadcopter). We demonstrate the robustness of our learned policy by showing the recovery of the tilt-rotor platform in the simulation from various non-static initial conditions in order to reach a desired state. The developmental policy for the tilt-rotor UAV also showed superior fault tolerance when compared with the policy learned from the scratch. The results show the ability of the presented approach to bootstrap the learned behavior from a simpler system (lower-dimensional action-space) to a more complex robot (comparatively higher-dimensional action-space) and reach better performance faster.
Dynamic Modeling of Voice Coil Motor-Actuated Flexible Membranes
Authors: Shi Hongyang , Pinto Thassyo , Qi Xinda , Coleman Demetris , Matt Silvia , Hou Weilin , Tan Xiaobo
Published: January 2021

In this paper, we derive a dynamical model for a controllable flexible membrane which is point-actuated by distributed voice coil motors (VCM) connected to it. Besides the modal analysis of the membrane motion, which is the only dynamics discussed in most of related published works treating external pressures as inputs, we integrate the dynamics of the voice coil motors including mechanics and electrical dynamics into the whole system, leaving the electrical signals as inputs to the VCM-actuated membrane system, which is useful for practical application. Also, the multiple-input-multiple-output (MIMO) system is simplified by transforming the dynamics equations into Laplace domain and into a matrix form, which makes the derived transfer functions concise and easier for analysis. It is demonstrated that the eigenmodes of an undamped free-vibration model can be used for approximating the deflection of a forced damping membrane. Furthermore, a reduced-order model is constructed for the flexible membrane system with two voice coil motors symmetrically located on the diameter of the membrane, which is subsequently validated with experimental results obtained on a 2-by-1-VCM-actuated membrane prototype.
Nonholonomic Systems With Redundant Degrees of Freedom Can Exploit Nonlinear Frequency Response to Improve Speed and Efficiency of Locomotion
Authors: Fedonyuk Vitaliy , Rodwell Colin , Tallapragada Phanindra
Published: January 2021

Rigid body nonholonomic systems serve as models for locomotion of several terrestrial animals such as snakes as well as for fish-like swimming motion. Several well known nonholonomic systems have also found applications in the field of mobile robotics in everything from wheeled vehicles to articulated snake like robots. However, one aspect of their dynamics has remained unexplored. This is to do with the effects of increasing the degrees of freedom by adding additional ‘segments’ such as in a chain, with the joints between segments having a nonzero torsional stiffness. Such nonholonomic systems when subjected to periodic actuation or inputs have additional modes of oscillation. The interplay of the nonholonomic constraints, linear elastic potentials and additional degrees of freedom can produce rich frequency-amplitude response in the dynamics of the system and can lead to significantly higher speed and efficiency. In this paper we explore such dynamics with the example of a well known nonholonomic system, the Chaplygin sleigh and a variant of it with an additional degree of freedom. Such models can be expected to better match the dynamics of biological swimmers and have widespread applications for soft and under-actuated robots.
A Review of Nonpharmacological Strategies in the Treatment of Relative Energy Deficiency in Sport
Authors: Kuikman Megan A. , Mountjoy Margo , Stellingwerff Trent , Burr Jamie F.
Published: January 2021

Relative energy deficiency in sport (RED-S) can result in negative health and performance outcomes in both male and female athletes. The underlying etiology of RED-S is low energy availability (LEA), which occurs when there is insufficient dietary energy intake to meet exercise energy expenditure, corrected for fat-free mass, leaving inadequate energy available to ensure homeostasis and adequate energy turnover (optimize normal bodily functions to positively impact health), but also optimizing recovery, training adaptations, and performance. As such, treatment of RED-S involves increasing energy intake and/or decreasing exercise energy expenditure to address the underlying LEA. Clinically, however, the time burden and methodological errors associated with the quantification of energy intake, exercise energy expenditure, and fat-free mass to assess energy availability in free-living conditions make it difficult for the practitioner to implement in everyday practice. Furthermore, interpretation is complicated by the lack of validated energy availability thresholds, which can result in compromised health and performance outcomes in male and female athletes across various stages of maturation, ethnic races, and different types of sports. This narrative review focuses on pragmatic nonpharmacological strategies in the treatment of RED-S, featuring factors such as low carbohydrate availability, within-day prolonged periods of LEA, insufficient intake of bone-building nutrients, lack of mechanical bone stress, and/or psychogenic stress. This includes the implementation of strategies that address exacerbating factors of LEA, as well as novel treatment methods and underlying mechanisms of action, while highlighting areas of further research.
mSphere of Influence: No More Excuses—Addressing Race, Racism, and Socioeconomic Issues in the Science Classroom and Laboratory
Authors: Guiton Pascale S.
Published: January 2021

Pascale Guiton works in the field of parasitology at a primarily undergraduate institution. In this mSphere of Influence article, she reflects on her difficulties as a faculty of color to discuss socioscientific issues in her classrooms. T.
An Observational Laboratory-Based Assessment of SARS-CoV-2 Molecular Diagnostics in Benin, Western Africa
Authors: Sander Anna-Lena , Yadouleton Anges , Moreira-Soto Andres , Tchibozo Carine , Hounkanrin Gildas , Badou Yvette , Fischer Carlo , Krause Nina , Akogbeto Petas , F. de Oliveira Filho Edmilson , Dossou Anges , Brünink Sebastian , Drosten Christian , Aïssi Melchior A. Joël , Harouna Djingarey Mamoudou , Hounkpatin Benjamin , Nagel Michael , Drexler Jan Felix
Published: January 2021

Months after the start of the COVID-19 pandemic, case numbers from Africa are surprisingly low, potentially because the number of SARS-CoV-2 tests performed in Africa is lower than in other regions. Here, we show an overload of COVID-19-related diagnostics in the central laboratory of Benin, Western Africa, with a stagnating average number of positive samples irrespective of daily sample counts.
Protracted northward drifting of South China during the assembly of Gondwana: Constraints from the spatial-temporal provenance comparison of Neoproterozoic–Cambrian strata
Authors: Chen Qiong , Zhao Guochun , Sun Min
Published: January 2021

Neoproterozoic to Paleozoic sedimentation shows systematic temporal-spatial variations within South China, which must be considered in reconstructing geological evolution of South China in response to global plate reorganization from the breakup of Rodinia to the assembly of Gondwana. We use >1000 new U-Pb and Hf isotopic data for detrital zircons from Neoproterozoic–Cambrian strata across the western (i.e., Longmenshan) and eastern (i.e., Wuyishan) margins of South China, coupled with compiled stratigraphic and magmatic information, to constrain change in provenance through time. First-order conclusions are as follows: (1) detrital zircons from the Neoproterozoic strata of the two margins were mainly sourced from the Panxi-Hannan arc and the Jiangnan orogen, signaling a rough self-sufficient sedimentary system; (2) newly identified Cambrian molasse-like sediments in the western margin, in which abundant detrital zircons are 550–500 Ma old with positive εHf(t) values, were mainly derived from the 580–500 Ma Cadomian arc belt along the Iran-Turkey margin; and (3) the Cambrian sediments in the eastern margin document more increased contributions from the Grenvillian-age provinces most possibly in Australia. Such spatial-temporal provenance variations signal the northward drifting of South China, from a position connecting with Iran-Turkey and northern India to that approaching Australia during the late Neoproterozoic–Cambrian period. We highlight that the activity of oblique oceanic-continental convergence accreted Asian terranes onto the northern margin of Gondwana, hence contributing to the ultimate Gondwana architecture under global plate reorganization.
Variability in preventive care practices among US adults with diabetes mellitus
Authors: Baccaglini Lorena , Kusi Appiah Adams , Ray Mahua , Yu Fang
Published: January 2021

Introduction

Patients with diabetes are advised to follow standard medical care including daily blood glucose and foot checks, eye examinations with pupil dilation, and cholesterol checks to prevent diabetes-related complications. It is unclear how these practices currently vary across different US population subgroups. The objective of this study was to assess variation in overall and individual diabetes care practices and identify specific factors associated with differences in these practices in a representative sample of US diabetic adults.

Research design and methods

Cross-sectional data were from the 2017 Behavioral Risk Factor Surveillance System. Survey logistic regression was used to account for the complex sampling design.

Results

Among 30 780 eligible participants, 8957 (equivalent to 28% of the target population) followed all four diabetes care practices. Insulin-dependent participants had higher adjusted odds (adjusted OR=2.95; 95% CI 2.62 to 3.31) of following all four diabetic care practices compared with those who did not. Cost-related variables (having healthcare coverage and/or a personal doctor) were positively associated with diabetes care practices, with the strongest association observed for adherence to more costly practices (annual eye examination and cholesterol check) versus less costly ones (daily blood glucose check, daily foot check).

Conclusions

Our findings suggest the need for diabetes care practice-specific and population subgroup-specific public health interventions to encourage early adherence to diabetic care practices and reduce complications.
Impact on health and provision of healthcare services during the COVID-19 lockdown in India: a multicentre cross-sectional study
Authors: Raman Rajiv , Rajalakshmi Ramachandran , Surya Janani , Ramakrishnan Radha , Sivaprasad Sobha , Conroy Dolores , Thethi Jitendra Pal , Mohan V , Netuveli Gopalakrishnan
Published: January 2021

Introduction

The COVID-19 pandemic resulted in a national lockdown in India from midnight on 25 March 2020, with conditional relaxation by phases and zones from 20 April. We evaluated the impact of the lockdown in terms of healthcare provisions, physical health, mental health and social well-being within a multicentre cross-sectional study in India.

Methods

The SMART India study is an ongoing house-to-house survey conducted across 20 regions including 11 states and 1 union territory in India to study diabetes and its complications in the community. During the lockdown, we developed an online questionnaire and delivered it in English and seven popular Indian languages (Hindi, Tamil, Marathi, Telegu, Kannada, Bengali, Malayalam) to random samples of SMART-India participants in two rounds from 5 May 2020 to 24 May 2020. We used multivariable logistic regression to evaluate the overall impact on health and healthcare provision in phases 3 and 4 of lockdown in red and non-red zones and their interactions.

Results

A total of 2003 participants completed this multicentre survey. The bivariate relationships between the outcomes and lockdown showed significant negative associations. In the multivariable analyses, the interactions between the red zones and lockdown showed that all five dimensions of healthcare provision were negatively affected (non-affordability: OR 1.917 (95% CI 1.126 to 3.264), non-accessibility: OR 2.458 (95% CI 1.549 to 3.902), inadequacy: OR 3.015 (95% CI 1.616 to 5.625), inappropriateness: OR 2.225 (95% CI 1.200 to 4.126) and discontinuity of care: OR 6.756 (95% CI 3.79 to 12.042)) and associated depression and social loneliness.

Conclusion

The impact of COVID-19 pandemic and lockdown on health and healthcare was negative. The exaggeration of income inequality during lockdown can be expected to extend the negative impacts beyond the lockdown.
Acute pain management among patients with opioid maintenance therapy: specificities and difficulties identified in primary care: a qualitative study
Authors: Guillou Landreat Morgane , Baillot Melia , Le Goff Delphine , Le Reste Jean Yves
Published: January 2021

Objectives

In the last 30 years, opioid maintenance treatment prescription (OMT) has changed patients’ and also changed physicians’ practices. General practitioners (GPs) have to deal with patients on OMT who are in acute pain. The objective of this qualitative study was to explore medical care challenges and solutions identified by GPs in the management of acute pain among patients receiving OMT.

Design and setting

Qualitative study with semistructured interviews were used as a data collection technique with a sampling strategy using a snowball sampling method to obtain a purposive sample of practicing GPs. Analysis was undertaken using a thematic analysis method.

Participants

Twelve GPs, working in France (Brittany) who prescribe OMT were interviewed.

Results

The thematic analysis resulted in two main themes relating to specificities and difficulties identified: (1) Medical care and training challenges identified by GPs treating patients on OMT with acute pain, with four subthemes : management of these situations not concerning primary care, lack of training prompts GPs to rely on peer and specialist support, lack of guidelines and conflicting recommendations between clinicians in different settings (2) linked to the patient–GP relationship, with six subthemes: Implementing an individualised centred approach, acute pain management during OMT relies on a relationship based on trust, GPs found difficulties in evaluating and treating pain, difficulties in care adherence, fear of patients destabilisation, fear of misuse and diversion.

Conclusion

The complexity of acute pain and OMT entails significant challenges for clinicians and patients. In primary care, it is hard to achieve a balance between pain relief and opioid use disorder treatment, in a global patient-centred approach. Fear of misuse or diversion was not a important factor, except for patients not known to the practitioners, but GPs were concerned with the risks of patient destabilisation in situations of acute pain.
Quality of life in paediatric solid tumours: a randomised study of metronomic chemotherapy versus placebo
Authors: Pramanik Raja , Agarwala Sandeep , Sreenivas Vishnubhatla , Dhawan Deepa , Bakhshi Sameer
Published: January 2021

Objective

Health-related quality of life (HRQoL) is an important outcome for paediatric cancer studies. We compared the HRQoL between patients of progressive paediatric solid tumours randomised to metronomic chemotherapy versus placebo.

Methods

In this double-blinded, placebo-controlled randomised study of 108 children with progressive malignancies, HRQoL was evaluated using the PedsQOL Cancer module V.3 at baseline (A1), A2 (9 weeks or earlier if progressed) or A3 (18 weeks or earlier if progressed).

Results

There was no statistically significant difference in the change in quality of life produced by each arm from A1 to A2 in either mean total scores or individual domain scores, reported by children or their parents. On analysing the response according to the minimal clinically important difference, defined as an improvement by 4.5 points, we found no significant differences, be it among bone-sarcomas, other tumours, responders (those who received ≥9 weeks of treatment) or non-responders.

Conclusions

The present study concludes that there was no significant difference in HRQoL, between the patients in the two arms at second and later assessments. This is consistent with the other survival endpoints in the study.

Trial registration number

Clinical trial registration: clinicaltrials.gov Identifier:NCT01858571.
Antibiotic use towards the end of life: development of good practice recommendations
Authors: Seaton R Andrew , Cooper Lesley , Fairweather Jack , Fenning Stephen , Ferguson Libby , Galbraith Susan , Duffy Tony , Sneddon Jacqueline
Published: January 2021

Objectives

Development of evidence-based good practice recommendations for clinicians considering the use of antibiotics in patients towards the end of life.

Design

A multiprofessional group of experts in end-of-life care and antimicrobial stewardship was convened. Findings from a scoping review of the literature and a consultation of clinicians were triangulated. Expert discussion was used to generate consensus on how to approach decision-making.

Setting

Representatives from hospital and a range of community health and care settings.

Participants

Medical, pharmacy and nursing professionals.

Main outcome measures

Good practice recommendations based on published evidence and the experience of prescribers in Scotland.

Results

The findings of 88 uncontrolled, observational studies of variable quality were considered alongside a survey of over 200 prescribers. No national or international guidelines were identified. Antibiotic use towards the end of life was common but practice was highly variable. The potential harms associated with giving antibiotics tended to be less well considered than the potential benefits. Antibiotics often extended the length of time to death but this was sometimes at the cost of higher symptom burden. There was strong consensus around the importance of effective communication with patients and their families and making treatment decisions aligned to a patient’s goals and priorities.

Conclusions

Good practice recommendations were agreed with focus on three areas: making shared decisions about future care; agreeing clear goals and limits of therapy; reviewing all antibiotic prescribing decisions regularly. These will be disseminated widely to support optimal care for patients towards the end of life. A patient version of the recommendations has also been produced to support implementation.
Moving from tradition-based to competence-based psychotherapy
Authors: Rief Winfried
Published: January 2021

Current education and training in psychological interventions is mostly based on different ‘schools’ (traditions such as cognitive–behavioural or psychodynamic therapy), and strong identification with these specific traditions continuously hinders a scientifically based development of psychotherapy. This review is selective rather than systematic and comprehensive. In addition to the consideration of other influential publications, we relied on a literature search in Web of Science using the following terms (update: 24 December 2020): (psychotherapy AND meta-analy* AND competence*). After summarising current problems, a pathway for solving these problems is presented. First, we have to recategorise psychological interventions according to the mechanisms and subgoals that are addressed. The interventions can be classified according to the foci: (1) skills acquisition (eg, communication, emotion regulation, mentalisation); (2) working with relationship patterns and using the therapeutic relationship to modify them; and (3) clarification of motives and goals. Afterwards, the training of psychotherapists can switch from focusing on one theoretical framework to learning the different competences for modification according to these new categories. The selection of topics to be addressed should follow best evidence-based mechanisms and processes of mental disorders and interventions. Psychology offers knowledge about these mechanisms that can be understood as a basic science for psychological treatments in general. This requires better connection with basic science, new research efforts that focus on treatment subgoals, theory-overarching optimisation of the selection and personalisation of treatments, and new types of training for psychotherapists that are designed to optimise therapists’ competences accordingly, instead of limiting training programmes to one single theoretical framework.
The enigmatic immunoglobulin G4-related disease and its varied cardiovascular manifestations
Authors: Shakir Aamina , Wheeler Yurong , Krishnaswamy Guha
Published: January 2021

Immunoglobulin G4-related disease (IgG4-RD) is a systemic fibroinflammatory disease characterised by multiorgan lymphoplasmacytic infiltration, obliterative phlebitis and storiform fibrosis. It can be associated with cardiovascular pathology. The objective of this narrative review is to summarise the published literature on cardiovascular manifestations of IgG4-RD and to provide a basis for diagnosis and management of the condition by the practising cardiologist.

We propose the following categorisations of cardiovascular IgG4-RD: aortitis, medium-vessel arteritis, pulmonary vascular disease, phlebitis, valvulopathy, pericarditis, myocardial disease and antineutrophilic cytoplasmic antibody-associated vasculitis. We also review herein developments in radiological diagnosis and reported medical and surgical therapies. Cardiovascular lesions frequently require procedural and/or surgical interventions, such as aortic aneurysm repair and valve replacement. IgG4-RD of the cardiovascular system results in serious complications that can be missed if not evaluated aggressively. These are likely underdiagnosed, as clinical presentations frequently mimic cardiovascular disease due to more common aetiologies (myocardial infarction, abdominal aortic aneurysm and so on). While systemic corticosteroids are the mainstay of IgG4-RD treatment, biological and disease-modifying agents are becoming more widely used. Cardiologists should be aware of cardiovascular IgG4-RD as a differential diagnosis, and understand the roles of corticosteroids, disease-modifying agents and biologicals, as well as their integration with surgical approaches. There are several knowledge gaps, including diagnosis, risk factors, pathogenesis and appropriate management in Ig4-RD of the cardiovascular system. Areas lacking well-conducted randomized trials include safety of steroids in the setting of vascular aneurysms and the role of disease-modifying drugs and biological agents in patients with established cardiovascular complications of this multifaceted enigmatic disease.
Rethinking immune checkpoint blockade: ‘Beyond the T cell’
Authors: Liu Xiuting , Hogg Graham D , DeNardo David G
Published: January 2021

The clinical success of immune checkpoint inhibitors has highlighted the central role of the immune system in cancer control. Immune checkpoint inhibitors can reinvigorate anti-cancer immunity and are now the standard of care in a number of malignancies. However, research on immune checkpoint blockade has largely been framed with the central dogma that checkpoint therapies intrinsically target the T cell, triggering the tumoricidal potential of the adaptive immune system. Although T cells undoubtedly remain a critical piece of the story, mounting evidence, reviewed herein, indicates that much of the efficacy of checkpoint therapies may be attributable to the innate immune system. Emerging research suggests that T cell-directed checkpoint antibodies such as anti-programmed cell death protein-1 (PD-1) or programmed death-ligand-1 (PD-L1) can impact innate immunity by both direct and indirect pathways, which may ultimately shape clinical efficacy. However, the mechanisms and impacts of these activities have yet to be fully elucidated, and checkpoint therapies have potentially beneficial and detrimental effects on innate antitumor immunity. Further research into the role of innate subsets during checkpoint blockade may be critical for developing combination therapies to help overcome checkpoint resistance. The potential of checkpoint therapies to amplify innate antitumor immunity represents a promising new field that can be translated into innovative immunotherapies for patients fighting refractory malignancies.
Immunologically programming the tumor microenvironment induces the pattern recognition receptor NLRC4-dependent antitumor immunity
Authors: Yu Xiaofei , Liu Wenjie , Chen Shixian , Cheng Xueqian , Paez Patrick A , Sun Tuanwei , Yuan Fang , Wei Chunyan , Landry Joseph W , Poklepovic Andrew S , Bear Harry D , Subjeck John R , Repasky Elizabeth , Guo Chunqing , Wang Xiang-Yang
Published: January 2021

Background

The efficacy of cancer immunotherapy can be limited by the poor immunogenicity of cancer and the immunosuppressive tumor microenvironment (TME). Immunologically programming the TME and creating an immune-inflamed tumor phenotype is critical for improving the immune-responsiveness of cancers. Here, we interrogate the immune modulator Flagrp170, engineered via incorporation of a pathogen-associated molecular pattern (ie, flagellin) into an immunostimulatory chaperone molecule, in transforming poorly immunogenic tumors and establishing a highly immunostimulatory milieu for immune augmentation.

Methods

Multiple murine cancer models were used to evaluate the immunostimulatory activity, antitumor potency, and potential side effects of Flagrp170 on administration into the tumors using a replication impaired adenovirus. Antibody neutralization and mice deficient in pattern recognition receptors, that is, toll-like receptor 5 (TLR5) and NOD like receptor (NLR) family caspase activation and recruitment domain (CARD) domain-containing protein 4 (NLRC4), both of which can recognize flagellin, were employed to understand the immunological mechanism of action of the Flagrp170.

Results

Intratumoral delivery of mouse or human version of Flagrp170 resulted in robust inhibition of multiple malignancies including head and neck squamous cell carcinoma and breast cancer, without tissue toxicities. This in situ Flagrp170 treatment induced a set of cytokines in the TME known to support Th1/Tc1-dominant antitumor immunity. Additionally, granulocyte macrophage colony-stimulating factor derived from mobilized CD8+T cells was involved in the therapeutic activity of Flagrp170. We also made a striking finding that NLRC4, not TLR5, is required for Flagrp170-mediated antitumor immune responses.

Conclusion

Our results elucidate a novel immune-potentiating activity of Flagrp170 via engaging the innate pattern recognition receptor NLRC4, and support its potential clinical use to reshape cancer immune phenotype for overcoming therapeutic resistance.
Effectiveness of very low profile thrombectomy device in primary distal medium vessel occlusion, as rescue therapy after incomplete proximal recanalization or following iatrogenic thromboembolic events
Authors: Rikhtegar Reza , Mosimann Pascal John , Weber Ralph , Wallocha Marta , Yamac Elif , Mirza-Aghazadeh-Attari Mohammad , Chapot René
Published: January 2021

Background

Recent progress with smaller retrievers has expanded the ability to reach distal brain arteries. We herein report recanalization, bleeding complications and short-term clinical outcomes with the smallest currently known low profile thrombectomy device in patients with primary or secondary distal medium vessel occlusion (DMVO).

Methods

We performed a retrospective analysis of 115 patients receiving mechanical thrombectomy (MT) in DMVO using the extended Thrombolysis in Cerebral Infarction (eTICI), European Cooperative Acute Stroke Study (ECASS) II classification, The National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) scores at admission and discharge to evaluate outcomes. Patients were stratified into three groups: (1) primary isolated distal occlusion (n=34), (2) secondary distal occlusion after MT of a proximal vessel occlusion (n=71), or (3) during endovascular treatment of aneurysms or arteriovenous malformations (AVMs) (n=10).

Results

Successful distal recanalization, defined as an eTICI score of 2b67, 2c and 3, was achieved in 74.7% (86/115) of patients. More specifically, it was 70.5% (24/34), 73.2% (52/71), and 100% (10/10) of primary DMVO, secondary DMVO after proximal MT, and rescue MT during aneurysm or AVM embolization, respectively. Symptomatic intraparenchymal bleeding occurred in 6.9% (eight patients). In-hospital mortality occurred in 18.1% (19/105) of patients with stroke. The most common cause of death was large infarct, old age, and therapy limitation.

Conclusion

Direct or rescue MT of DMVO using a very low profile thrombectomy device is associated with a high rate of successful recanalization and a reasonable rate of symptomatic hemorrhagic complication, despite a risk of 18.1% hospital mortality in elderly patients. Further trials are needed to confirm our results and assess long-term clinical outcomes.