bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding the relevance of surgical specialties in undergraduate medical education: Insights of graduates
Authors: Girón‐Luque Fernando , Téllez‐Rodríguez Luis‐Jaime , Rueda‐Gutiérrez Jorge , Vergel John
Published: November 2023

Background

The relevance of training medical students in surgical specialty services has been a matter of debate in contexts where the health care system focuses on primary health care. Some educators argue that medical students should be trained in primary care settings. Other educators assert that rotating in highly complex hospitals strengthens the competencies of future general practitioners. Nonetheless, little attention has been paid to the added value that rotations in surgical specialties have brought to newly graduated doctors' lives. In this study, we explored the perceptions of a group of graduates by focusing on the relevant experiences they had during their surgical specialty rotations in undergraduate medical training and how this training influenced their personal and professional life.

Methods

We conducted a qualitative study using a convenience sampling strategy to recruit a total of seven junior doctors. Data were collected through semi‐structured interviews in 2022. Thematic analysis was used to analyse the data until code saturation was reached.

Results

The recurring themes were (1) perception of rotations, (2) valuable learning for medical practice and (3) defining their professional future. Participants felt that their experiences in surgical specialty rotations were beneficial, as they gained confidence to perform professionally and decide on future employment and strengthened their research and primary healthcare competencies.

Conclusion

Although training in primary healthcare centres is crucial in undergraduate medical education, these results suggest that including rotations in surgical specialties may be valuable in enhancing the future careers of junior doctors.
What do you think of when you hear the word ‘feedback’? A reflective thematic analysis study of interviews
Authors: Alansari Reem , Lim Pei‐Wen , Ramani Subha , Palaganas Janice C.
Published: November 2023

Purpose

Although most teaching around feedback focuses on the delivery, one must consider that the word ‘feedback’ is not a neutral word. It inflicts a range of emotions that, when used, may influence the effectiveness of the feedback process. A more profound understanding of health professions educators' perceptions regarding the word ‘feedback’ can help explain discrepancies between the provision, reception and acceptance of feedback.

Methods

This is a qualitative inductive, reflective thematic analysis study. The authors interviewed 22 health professions educators participating in an online workshop to develop their feedback giving skills on their initial perspectives of the word ‘feedback’.

Results

We found four major themes: (1) Can I tell you a little story about my feedback experience? (2) It is probably going to be negative. (3) There is always something to learn if you are willing to hear the message. (4) It is like getting a report card. From the data, we suggest one key antecedent and two practical approaches one could take when giving feedback.

Conclusion

In this article, the authors highlight barriers during the feedback process due to the mere perception of the nature of feedback and the connotations associated with the term itself and suggest approaches that can refocus conversations towards a shared meaning and purpose of improvement, despite the preconceptions of the word ‘feedback’.
Bayesian true prevalence estimation of brucellosis in sheep, goats, cattle and camels in southeast regions of Iran
Authors: Meletis Eleftherios , Sakhaee Ehsanollah , Kostoulas Polychronis
Published: November 2023

Aims and Methods

Brucellosis is worldwide one of the most prevalent zoonotic diseases with serious public health hazard affecting domestic livestock and causing economic losses. Objective of this study is to estimate the true prevalence of brucellosis in livestock, specifically cattle, sheep, goats and camels, using a novel Bayesian latent class model, adjusting for the imperfect sensitivity and specificity of the applied tests, where the second test was restricted only to first test‐positive samples.

Results

Brucellosis seems more prevalent in goats and sheep, while the posterior medians and 95% probability intervals (95% PI) for the average true prevalence for sheep, goats, cattle and camels are 18% (4%–43%), 19% (7%–37%), 16% (5%–34%) and 18% (1%–48%) respectively.

Conclusions

The study results indicate that brucellosis is highly endemic in Iran and crucial steps are needed to control and raise awareness about the high public health concern of the disease.
Information needs of stroke survivors and their family members regarding post-stroke cognition: a scoping review protocol
Authors: Hobden Georgina , Demeyere Nele
Published: November 2023

Objective:

The aim of this review is to map current evidence describing the information needs of stroke survivors and family members regarding cognition.

Introduction:

Managing cognitive changes is the most frequently reported unmet need among stroke survivors; hence, there is an urgent need to improve support for post-stroke cognitive impairment. While there is evidence that psychoeducation may help stroke survivors and their family members develop awareness about cognitive impairment and self-management strategies, it is unclear what information stroke survivors and their family members want to receive and how their needs change over time.

Inclusion criteria:

This review will consider peer-reviewed articles describing information needs relating to the following cognitive domains: memory, language, attention, executive function, praxis, and number processing. Stroke survivors and/or their family members must comprise at least 50% of the study population and must be aged at least 18 years. Quantitative, qualitative, and mixed methods studies will be included.

Methods:

The review will be conducted in line with the JBI methodology for scoping reviews. A full literature search will be conducted in MEDLINE (PubMed), PsycINFO (Ovid), Embase, CINAHL (EBSCOhost), and Scopus using a search strategy developed in consultation with an expert university librarian. Articles will be screened by title, abstract, and full text; then, data will be extracted by 2 independent reviewers. The reference lists of included articles will be hand-searched for additional material. Data analysis and reporting will involve qualitative (textual narrative synthesis) and quantitative (descriptive statistics) methods.
Biophysical, thermo‐physiological and perceptual determinants of cool‐seeking behaviour during exercise in younger and older women
Authors: Valenza Alessandro , Blount Hannah , Bianco Antonino , Worsley Peter R. , Filingeri Davide
Published: November 2023

Women continue to be under‐represented in thermoregulatory research despite their undergoing unique physiological changes across the lifespan. This study investigated the biophysical, thermo‐physiological, and perceptual determinants of cool‐seeking behaviour during exercise in younger and older women. Eleven younger (25 ± 5 years; 1.7 ± 0.1 m; 63.1 ± 5.2 kg) and 11 older women (53 ± 6 years; 1.7 ± 0.1 m; 65.4 ± 13.9 kg) performed a 40‐min incremental cycling test in a thermoneutral environment (22 ± 1.7°C; 36 ± 4% relative humidity). Throughout the test, participants freely adjusted the temperature of a cooling probe applied to their wrists to offset their thermal discomfort. We continuously recorded the probe–wrist interface temperature to quantify participants’ cool‐seeking behaviour. We also measured changes in participants’ rate of metabolic heat production, core and mean skin temperatures, and skin wetness. Finally, we body‐mapped participants’ skin heat, cold and wetness sensitivity. Our results indicated that: (1) older and younger women exhibited similar onset and magnitude of cool‐seeking behaviour, despite older women presented reduced autonomic heat‐dissipation responses (i.e., whole‐body sweat losses); (2) older women's thermal behaviour was less determined by changes in core temperature (this being a key driver in younger women), and more by changes in multiple thermo‐physiological and biophysical parameters (i.e., physical skin wetness, temperature and heat production); (3) older women did not present lower regional skin thermal and wetness sensitivity than younger women. We conclude that predictions of female cool‐seeking behaviours based on thermo‐physiological variables should consider the effects of ageing. These findings are relevant for the design of wearable cooling systems and sports garments that meet the thermal needs of women across the lifespan.
Neuromuscular State Estimation Via Space-by-Time Neural Signal Decomposition
Authors: Baskaran Avinash , Hollinger David S. , Hailey Rhet O. , Zabala Michael E. , Rose Chad G.
Published: November 2023

Robotic exoskeletons for the hand are being explored to improve health, safety, and physical performance. However, much research effort is needed to establish reliable models of human behavior for effective human–robot interaction control. In this work, surface electromyography is used to measure and model muscle activity of healthy participants performing quasi-isometric and dynamic hand exercises. Non-negative matrix tri-factorization is used to extract hidden neuromuscular parameters encoded in spatial and temporal muscle synergies, which are used to estimate probabilistic linear models of intent, effort, and fatigue. This paper thereby presents steps toward reliable modeling of nonlinear time-varying hand neuromuscular dynamics for intuitive and robust human–robot interaction.
Nonlinear Evaluation of a Large-Stroke Coiled L-Shape Compliant Guiding Mechanism With Constant Stiffness
Authors: Ling Mingxiang , Zhao Linfeng , Wu Shilei , Chen Liguo , Sun Lining
Published: November 2023

Owing to the advantages of monolithic structure and little need for assembling, compliant guiding mechanisms appear to be an effective solution for decoupling multi-freedom precision motions but are still prone to geometric nonlinearities of parasitic error and stiffening effect for large strokes. This paper proposes a coiled L-shape compliant guiding mechanism featuring millimeter-scale strokes with a compact structure, constant stiffness, and minimized parasitic error. The coiled compliant guiding mechanism is formed by convolving L-shape flexure beams in a zigzag configuration with decoupled XY motions achieved. Its geometrically nonlinear parasitic error, variation in stiffness, and primary vibration are captured by using a dynamic beam constraint model (DBCM). It is theoretically, numerically, and experimentally found, by comparing with double parallel guiding mechanisms, that the kinetostatic and dynamic behaviors of the coiled L-shape compliant mechanism are nearly independent on the applied force within intermediate-deformation ranges. Such a weak geometric nonlinearity with the minimized influence of axially loaded stiffening and kinematics-arching effects is much different from the double parallel guiding mechanisms. The obtained results indicate that large strokes with constant stiffness and invariable resonance frequency can be realized, which also allows small parasitic errors.
A Method for Preliminary Design of Variable Geometry Vaned Diffuser for Centrifugal Compressor
Authors: Tamaki Hideaki , Yamaguchi Satoshi
Published: November 2023

Centrifugal compressors require a wide operating range as well as high efficiency. Typical active control forms to enhance the operating range are suction throttling with a valve in a suction line, discharge throttling with a ring installed in a vaneless diffuser, variable inlet guide vanes, and variable geometry vaned diffuser (VVD). This study focuses on the design of a VVD whose vane rotates around a pivot to adjust its opening and proposes a method to estimate the main parameters of the VVD at the preliminary design stage. The design method here is based on matching the diffuser vane inlet angles with the flow angles at the diffuser inlet. If the designed VVD can maintain low incidence at the diffuser vane leading edge over the whole movable range of the vane is evaluated. A graph, which indicates the relation between the diffuser vane inlet angles and the flow angles at the diffuser inlet at diffuser choking and diffuser stalling, makes the evaluation easy. The proposed procedures were applied to select the number of vanes of the VVD for a turbocharger compressor. Tests for the validation of the design procedures were conducted by using fixed vaned diffusers that simulated the VVDs installed on the turbocharger with an 85 mm-diameter impeller. The results showed the effectiveness of the proposed design procedures. This paper first presents examples of applications of the typical active methods extending centrifugal compressors’ operating range for real machines and then discusses the design of VVD.
Eco-Driving Control of Connected and Automated Vehicles Using Neural Network–Based Rollout
Authors: Paugh Jacob , Zhu Zhaoxuan , Gupta Shobhit , Canova Marcello , Stockar Stephanie
Published: November 2023

Connected and autonomous vehicles have the potential to minimize energy consumption by optimizing the vehicle velocity and powertrain dynamics with Vehicle-to-Everything info en route. Existing deterministic and stochastic methods created to solve the eco-driving problem generally suffer from high computational and memory requirements, which makes online implementation challenging. This work proposes a hierarchical multi-horizon optimization framework implemented via a neural network. The neural network learns a full-route value function to account for the variability in route information and is then used to approximate the terminal cost in a receding horizon optimization. Simulations over real-world routes demonstrate that the proposed approach achieves comparable performance to a stochastic optimization solution obtained via reinforcement learning, while requiring no sophisticated training paradigm and negligible on-board memory.
Semi-Physical Modeling of Soft Pneumatic Actuators With Stiffness Tuning
Authors: Fairchild Preston , Shephard Noah , Mei Yu , Tan Xiaobo
Published: November 2023

The inherent low stiffness in soft robots makes them preferable for working in close proximity to humans. However, having this low stiffness creates challenges when operating in terms of control and sensitivity to disturbances. To alleviate this issue, soft robots often have built-in stiffness tuning mechanisms that allow for controlled increases in stiffness. Additionally, redundant pneumatic manipulators can utilize antagonistic pressure to achieve identical positions under increased stiffness. In this paper, we develop a model to predict the stiffness and configuration of a pneumatic soft manipulator under different pressure inputs and external forces. The model is developed based on the physical characteristics of a soft manipulator while enabling efficient parameter estimation and computation. The efficacy of the modeling approach is supported via experimental results.
A Novel Liquid Cooling Battery Thermal Management System With a Cooling Plate Based on Biomimetic Fractal Channels
Authors: Tang Zhiguo , Xiang Yi , Li Man , Cheng Jianping
Published: November 2023

An effective battery thermal management system (BTMS) is necessary to quickly release the heat generated by power batteries under a high discharge rate and ensure the safe operation of electric vehicles. Inspired by the biomimetic structure in nature, a novel liquid cooling BTMS with a cooling plate based on biomimetic fractal structure was proposed. By developing the physical model of the BTMS, numerical calculations were conducted to analyze the impacts of the structural parameters of the cooling plate and the inlet velocity of the coolant on the thermal performance of the batteries. The results showed that the cooling plate can meet the heat dissipation requirements of high-temperature uniformity for the batteries under high discharge rates, especially under the extremely uniform channel distribution mode for the adjacent fractal branch at the same level. Moreover, the increase in the group number of fractal branches can improve the cooling capacity of the cooling plate and reduce the pressure drop of the coolant. The increase in the level number of channels, the length ratio, and the inlet velocity of the coolant can enhance the cooling capacity. However, these methods of enhancing heat transfer require more pump power consumption. When the group number of fractal branches is 4, the level number of channels is 3, the length ratio is 1, and the inlet velocity of the coolant is 0.5 m/s, the BTMS can control the maximum temperature and maximum temperature difference of the batteries under 4C-rate discharge within 31.68 °C and 4.15 °C, respectively. Finally, orthogonal test was conducted on four factors: the group number of fractal branches, the level number of channels, the length ratio, and the inlet velocity of the coolant. The results showed that the level number of branches is the most important structural parameter.
Control of an Asymmetric Cylinder With Two Individually Controlled Pump/Motors
Authors: Kärnell Samuel , Ericson Liselott
Published: November 2023

Pump-controlled asymmetric cylinders need some kind of compensation for the difference between the in- and outlet flow. This can be done by using valves or additional pump/motors. An advantage with using valves is that only one pump/motor is required, but problems with mode-switch oscillations are more likely to occur. On the other hand, cylinder areas should be well matched with the pump/motor displacements for pump/motor compensation if the pump/motors are fixed and connected to the same shaft. However, this problem is avoided if the pump/motors are individually controlled. Furthermore, with individually controlled pump/motors, it is possible to control the pressure in one of the cylinder chambers and the piston speed simultaneously. This paper is focusing on such architectures. There are several possible configurations for architectures and control strategies for individually controlled pump/motors, and some are compared here. Results show that one of the configurations is more efficient than the others, but that it is less efficient than valve-compensation (assuming large valves). A controller design where one pump/motor is used to control the speed and another to control the pressure is suggested. Results show that the controller should be adapted based on the mode of operation.
Improving Fluid Power System Simulation Through an AAS-Based Simulation Framework
Authors: Becker Malte , Heppner Sebastian , Alt Raphael , Kleinert Tobias , Schmitz Katharina
Published: November 2023

This contribution introduces a simulation framework to significantly improve the simulation-based engineering process based on the Asset Administration Shell (AAS). The current simulation-based engineering process is characterized by long development times, high error susceptibility, and low availability of suitable simulation models. These deficits are addressed by seamlessly linking component data and encapsulated simulation models. Seamless linking is realized based on the AAS, a concept for realizing virtual representations of an asset [1]. The encapsulation enables better availability of simulation models in the engineering process by allowing stakeholders to exchange simulation models domain- and tool-independently. For this purpose, the Functional Mock-up Interface (FMI) is used, and coupling mechanisms for a component-based encapsulation of fluid power simulation models are presented.

Based on the AAS, linking component data and encapsulated simulation models is realized to parameterize the simulation models and reduce the long development time and error susceptibility.

Therefore, three functionalities have been developed based on the AAS data model. The first functionality allows searching and finding components or component simulation models from repositories of relevant stakeholders. As a result, individual components can be requested from specific component manufacturers during the development process. The second functionality enables domain- and tool-independent integration of simulation models into a simulation environment by using automatic parameterization or direct integration of encapsulated simulation models. Automatic parameterization reduces the time required and possible susceptibility to errors during manual parameterization, a task requiring integrating many different parameter sources. Finally, the third functionality enables bidirectional synchronization between field devices and component simulation models. As a result, the machine manufacturer can offer simulation model-based error support to the operator or assist the operator during commissioning.

These functionalities result in a concept for a new AAS-based simulation framework, shown in this contribution. The concept is a solution for mentioned deficits in the simulation-based engineering process.
Reinforcement Learning-Based Control of a Hydraulic Press With Multiple Actuators
Authors: Makansi Faried , Huang Jingkai , Schmitz Katharina
Published: November 2023

Methods of reinforcement learning are finding great success in solving complex decision and control tasks across different domains and applications. In the frame of control tasks, these methods seek to produce optimized controllers by gathering experience through interaction with the target system. Such controllers, which are often referred to as agents, can be generated without the need for rigorous physical modeling, parameter identification, and detailed knowledge of the system. Moreover, these approaches potentially allow to actuate several actuators with heterogenous control signal types, such as proportional valves and switching valves. Together with the generic interaction-based training concept, these approaches are promising tools for the control of complex hydraulic applications. The general applicability of reinforcement learning-based controllers for hydraulic control tasks has been shown in literature. However, several design options are not clearly investigated, especially regarding the selection of algorithms and the simultaneous coordination of multiple actuators. Therefore, this paper presents a study on different concepts for the reinforcement learning-based control of multiple actuators in a hydraulic press. Furthermore, solutions using a stochastic on-policy actor-critic algorithm (PPO) and a deterministic off-policy actor-critic method (TD3) are compared in this context. The results show that a setup with individual agents for each valve slightly outperforms solutions where one agent is used to control multiple valves. Moreover, the TD3 algorithm appears to yield better results on the given task than PPO.
3D Printed Gerotor Pump Geometries for Soft-Robot Actuation
Authors: Gallentine James , Barth Eric J.
Published: November 2023

Often, fluidic soft robots are driven by large pneumatic or low-bandwidth hydraulic systems which struggle to meet performance objectives. This research presents the design of two morphologies of compact, positive displacement hydraulic pumps designed to act as power supplies for fluidic soft robots. These hydraulic pumps were designed to leverage additive manufacturing technology, creating cost-effective, yet volumetrically powerful units. The operational bandwidth of these pumps (> 10Hz) was substantially higher than the natural frequency of most elastomer-based soft robots (1–5Hz), allowing high control authority.

These designs allow for highly scalable pumps, with performance documented in the paper. Due to the 3D printed nature of the pump components, manufacture cost is greatly reduced when compared to machined components. Each was tested driving various soft robotic actuators, demonstrating high-bandwidth, yet precise operation.

With their minimal size, these pumps are candidates for un-tethered mobile soft robots, and their low weight and low noise allows them to be carried on the body for robotic actuators used in mobility rehabilitation.
Erosion Wear Analysis and Biomimetic Optimization of Solid Particles on Relief Valve
Authors: Cao Hao , Xu He , Sun Feng , Fan Weiwang
Published: November 2023

Hydraulic valve is a widely used mechanical component in hydraulic system. Its characteristics have great influence on the performance of hydraulic system. The surface of the relief valve spool is eroded by the erosion of particle pollutants in the oil. Erosion wear will lead to valve safety, stability decline. In this paper, the discrete phase model (DPM) was used to simulate the solid-liquid two-phase flow and and the results were analyzed. According to the erosion wear condition, a bionic valve core is designed by using bionic method. The erosion wear conditions of different kinds and diameter particles on valve were compared. The results show that different types and diameters have different erosion wear conditions on the valve core, and the bionic valve core has better erosion wear resistance than the prototype valve core. This paper provides a reference for further research on erosion and anti-erosion wear ability of bionic spool of relief valve.
A Programmable Multi-Functional Pressure-Compensated Multi-Way Valve Based on Differential Pressure Active Regulation
Authors: Wang Bo , Quan Long , Li Yunwei , Zhao Xingyu , Hao Yunxiao , Ge Lei
Published: November 2023

The traditional pressure-compensated multi-way valve generally have the problems of low flow control accuracy, limited flow range, and difficult flow fine-tuning. Therefore, this paper designs the pressure-compensated multi-way valve with active differential pressure regulation (PMVPR). Two proportional reducing valves (PRV) are used to change the force balance of the compensator spool, to realize the realtime regulation of the main valve differential pressure Δpm. Next, the strategies of disturbance compensation, variable gain control, nonlinear flow correction are designed. And the prototype of PMVPR and the feasibility of the proposed control strategy are experimentally verified. The experiment results show that by continuously controlling the output pressure of the PRV, the differential pressure Δpm can decrease to a minimum of 0.2 MPa and increase to a maximum of 1.6 MPa, and the flow of PMVPR varies within 40% to 140% of the rated flow; compensating the flow and spring force, the flow control accuracy of the PMVPR is improved, and the flow deviation of PMVPR can be reduced to less than 5% with different openings under 0∼35 MPa steady-state load characteristics; adopting the nonlinear flow correction strategy, the flow can change with the expected target flow, which has a good consistency. The new principle has impressive performance improvement of the entire valve and would provide new ideas for the further development of intelligent proportional multi-way valve and system.
Mixed Reality Technology: A Virtual Training Tool in Fluid Power Engineering
Authors: Azzam Israa , Pate Keith , Breidi Farid
Published: November 2023

Fluid power systems can be expensive and difficult to access, making it challenging to provide hands-on training. This work discusses the incorporation of Mixed Reality (MR) technology in Fluid Power applications for providing a virtual training environment that simulates the behavior of fluid power systems, allowing users to receive immediate feedback on the system’s performance. Mixed reality is a digitized-based technology that integrates a virtual environment with our real world by utilizing real-world sensor data and computer models. This technology allows running simulations that examine the complexity of highly-coupled systems, producing new digital environments where physical and digital elements can interact in real-time. With all these features, MR technology can be a practical training tool for running virtual simulations that mimic real-life industry settings. It can extend the user with a virtual training environment, thus preparing the next generation of fluid power engineers and specialists. Throughout this work, we present the development and capabilities of a digitized virtual copy of a hydraulic excavator’s arm in an MR environment as a proof of concept. The MR arm module is developed and deployed using Microsoft’s Mixed Reality Tool Kit (MRTK) for Unity through HoloLens 2 MR headset. The MR development involves generating virtual copies of the mechanical and hydraulic subsystems, conducting the virtual assembly, and creating a user interface in the MR environment to visualize and interact with the model. The developed MR module enables visualizing the excavator’s internal structure, conducting the virtual assembly, and running virtual simulations, all of which assist in training future fluid power operators. It is an effective training tool that helps train junior engineers/technicians, cutting down on cost and time.
Application of the Hydraulic Transformer Concept to Reduce Throttling Loss in a Multiple-Function Load Sensing System
Authors: Lengacher Jacob , Stump Patrick , Vacca Andrea , Jenkins Ryan , Pintore Francesco , Fiorati Stefano
Published: November 2023

A common problem encountered in state-of-the-art load-sensing (LS) systems is that of throttling losses due to load imbalance among hydraulic functions. Several architectures exist which resolve this challenge using multiple pumps — or accumulator-stabilized pressure rails — with dynamic switching of connections to minimize throttling losses. These solutions can be expensive and complex to implement, and can thus be unsuitable in cases when only one function causes the load imbalance. This work presents a solution based on a hydraulic transformer used to isolate one high-load, low-power actuator from the rest of the system while maintaining single pump LS functionality with lower throttling losses. This is accomplished by connecting a hydraulic transformer to an existing rotary function to boost the supplied pressure of the system to the level required by the high-load user. This boosted pressure is stabilized using an accumulator. This allows the main LS pumps in the system to operate at a pressure level set by the other functions.

The reference case considered is an Agricultural Tractor / Planter with four functions at similar load pressures and one requiring much higher pressure and much lower flow, which negatively affect energy efficiency. The paper describes the sizing of the proposed architecture using commercially available components, estimates its saving potential, and validates this potential with field tests. Experimental tests demonstrated a reduction in pump power of 37% over the baseline system for the most common operating conditions, demonstrating its viability as a method for reducing throttling losses caused by a load imbalance in the planter actuators.
Simulation Analysis of Flow Characteristics of a Novel Flap Check Valve Based on CFD Method
Authors: Peng Chao , Tan Shuang , Jin Sibo , Liangbin Xu , Lijun Chen , Xiaoping Ouyang
Published: November 2023

The traditional check valves mainly include lift check valves and swing check valves, but the lift check valve has a larger fluid resistance, and the swing check valve has a longer opening/closing time and slow dynamic response. In this paper, a new type of flap check valve is proposed based on the inspiration of the heart valve. To study the dynamic response of the valve and the flow characteristics of the flow field in the valve, a three-dimensional analysis model of the valve is established based on the dynamic mesh theory using the computational fluid dynamics (CFD) method, and the CFD simulation of the flow characteristics of the valve is carried out by setting the boundary conditions and working parameters. The transient flow field characteristics and the force state of the valve disc are discussed and analyzed. The simulation results show that: the dynamic response of the flap check valve in the process of opening and closing is faster than that of the swing check valve, and the flow line of the valve is close to laminar flow, so it is not easy to have turbulent flow phenomenon similar to that in the lift check valve.
Analysis and Simulation of Dynamics and Control of a Hydrostatic Wind Turbine
Authors: Leinberger Mark , Stelson Kim A.
Published: November 2023

Kω2 control, also called torque control, is a popular tool for maximizing wind turbine power in region 2. For hydrostatic wind turbines, the Kω2 law relates pressure and rotor speed. This work considers implementing the Kω2 law as pressure-regulation or rotor speed-regulation. Dimensionless, linearized models of these two approaches are used to investigate dynamics and control. Analysis shows that the mechanical rotor dynamics are much slower than the hydraulic transmission dynamics and that frictional and leakage losses have a negligible effect on system dynamics. Root locus analysis shows how systems responses change with variation of PID controller gains. Both control approaches require derivative controller action to sufficiently damp their responses; both are also fundamentally limited in their speed of response by a slow stable pole regardless of their controller loop gains. Nonlinear system simulation shows that both control approaches track the maximum power point with nearly identical transient behavior and experience nearly identical power losses when using suboptimal values of the control law gain K.
Adaptive Sliding Mode Control Based on the Immersion and Invariance Principle for the Accurate Spool Control of Proportional Servo Valve
Authors: Qiu Zhi , Zhang Junhui , Su Qi , Li Haibin , Xu Bing , Wang Jiasheng
Published: November 2023

Due to the wide working range of the proportional servo valve (PSV), the flow force changes greatly with the load pressure drop, which significantly affects the precise control of the valve spool position of the PSV. An adaptive sliding mode control based on the immersion and invariance principle (ASMCII) is designed in this paper to solve this problem. The load pressure drop is adaptive to the pressure senseless PSV, and then the ASMCII is used to achieve high precision control. Firstly, the dynamic model of PSV system under unknown large flow force disturbances is established, and the sliding mode control strategy based on reaching law is designed and applied. Secondly, in the design of disturbance estimation error manifold, the immersion and invariance principle (I&I) are applied to ensure the estimation error of load pressure drop converges to 0, for the sake of the accurate estimation of flow force. Finally, the stability analysis and simulation of the system are carried out. The results show that under the simulation conditions of 0–35 MPa, ASMCII converges uncertain pressure drops quickly to compensate flow force completely, which promotes both static and dynamical performance significantly contrast to PID and the sliding mode control.
Quantum diamond microscope for dynamic imaging of magnetic fields
Authors: Tang Jiashen , Yin Zechuan , Hart Connor A. , Blanchard John W. , Oon Jner Tzern , Bhalerao Smriti , Schloss Jennifer M. , Turner Matthew J. , Walsworth Ronald L.
Published: November 2023

Wide-field imaging of magnetic signals using ensembles of nitrogen-vacancy (NV) centers in diamond has garnered increasing interest due to its combination of micron-scale resolution, millimeter-scale field of view, and compatibility with diverse samples from across the physical and life sciences. Recently, wide-field NV magnetic imaging based on the Ramsey protocol has achieved uniform and enhanced sensitivity compared to conventional measurements. Here, we integrate the Ramsey-based protocol with spin-bath driving to extend the NV spin dephasing time and improve magnetic sensitivity. We also employ a high-speed camera to enable dynamic wide-field magnetic imaging. We benchmark the utility of this quantum diamond microscope (QDM) by imaging magnetic fields produced from a fabricated wire phantom. Over a 270 × 270 μm2 field of view, a median per-pixel magnetic sensitivity of 4.1(1) nT /Hz is realized with a spatial resolution ≲ 10 μm and sub-millisecond temporal resolution. Importantly, the spatial magnetic noise floor can be reduced to the picotesla scale by time-averaging and signal modulation, which enables imaging of a magnetic-field pattern with a peak-to-peak amplitude difference of about 300 pT. Finally, we discuss potential new applications of this dynamic QDM in studying biomineralization and electrically active cells.
Iron deficiency–induced ferritinophagy impairs skeletal muscle regeneration through RNF20-mediated H2Bub1 modification
Authors: Che Yunshu , Li Jinteng , Wang Peng , Yu Wenhui , Lin Jiajie , Su Zepeng , Ye Feng , Zhang Zhaoqiang , Xu Peitao , Xie Zhongyu , Wu Yanfeng , Shen Huiyong
Published: November 2023

Iron deficiency (ID) is a widespread condition concomitant with disease and results in systemic dysfunction of target tissues including skeletal muscle. Activated by ID, ferritinophagy is a recently found type of selective autophagy, which plays an important role in various physiological and pathological conditions. In this study, we demonstrated that ID-mediated ferritinophagy impeded myogenic differentiation. Mechanistically, ferritinophagy induced RNF20 degradation through the autophagy-lysosomal pathway and then negatively regulated histone H2B monoubiquitination at lysine-120 in the promoters of the myogenic markers
MyoD
and
MyoG
, which inhibited myogenic differentiation and regeneration. Conditional knockout of NCOA4 in satellite cells, overexpression of RNF20 or treatment with 3-methyladenine restored skeletal muscle regenerative potential under ID conditions. In patients with ID, RNF20 and H2Bub1 protein expression is downregulated in skeletal muscle. In conclusion, our study indicated that the ferritinophagy-RNF20-H2Bub1 axis is a pathological molecular mechanism underlying ID-induced skeletal muscle impairment, suggesting potential therapeutic prospects.
Attribution of individual methane and carbon dioxide emission sources using EMIT observations from space
Authors: Thorpe Andrew K. , Green Robert O. , Thompson David R. , Brodrick Philip G. , Chapman John W. , Elder Clayton D. , Irakulis-Loitxate Itziar , Cusworth Daniel H. , Ayasse Alana K. , Duren Riley M. , Frankenberg Christian , Guanter Luis , Worden John R. , Dennison Philip E. , Roberts Dar A. , Chadwick K. Dana , Eastwood Michael L. , Fahlen Jay E. , Miller Charles E.
Published: November 2023

Carbon dioxide and methane emissions are the two primary anthropogenic climate-forcing agents and an important source of uncertainty in the global carbon budget. Uncertainties are further magnified when emissions occur at fine spatial scales (<1 km), making attribution challenging. We present the first observations from NASA’s Earth Surface Mineral Dust Source Investigation (EMIT) imaging spectrometer showing quantification and attribution of fine-scale methane (0.3 to 73 tonnes CH
4
hour
−1
) and carbon dioxide sources (1571 to 3511 tonnes CO
2
hour
−1
) spanning the oil and gas, waste, and energy sectors. For selected countries observed during the first 30 days of EMIT operations, methane emissions varied at a regional scale, with the largest total emissions observed for Turkmenistan (731 ± 148 tonnes CH
4
hour
−1
). These results highlight the contributions of current and planned point source imagers in closing global carbon budgets.
Structural and functional analyses of viral H2 protein of the vaccinia virus entry fusion complex
Authors: Kao Chi-Fei , Liu Chang-Yi , Hsieh Chia-Lin , Carillo Kathleen Joyce D. , Tzou Der-Lii M. , Wang Hao-Ching , Chang Wen
Published: November 2023

Virus-mediated membrane fusion involves conformational changes of the viral fusion protein to fuse the opposing viral and host lipid bilayers. Unlike all other known viruses that contain a single fusion protein, poxviruses harbor a multimeric protein complex of 11 subunits, termed the entry fusion complex (EFC), to mediate fusion with host membranes. Yet, how the poxviral EFC mediates membrane fusion remains enigmatic. To establish the mechanism of EFC-triggered membrane fusion, we are deciphering the structure and function of individual EFC components. Here, we determined the crystal structure of the H2 ectodomain by X-ray diffraction, revealing a folded conformation comprising a central five-stranded β-sheet and three cladding α-helices. We reconstructed the full-length H2 by
in silico
prediction, revealing that the N-terminal region (amino acids 51–90) of H2 protein may fold as a long helix connecting the ectodomain and transmembrane region. Using alanine-mutagenesis screening in a transient complementation system, coimmunoprecipitation, isothermal titration calorimetry, and mature virion (MV)-triggered membrane fusion assays, we concluded that the surface of the ectodomain of H2 protein, including two loop regions,
170
LGYSG
174
and
125
RRGTGDAW
132
, constitutes a broad A28-binding region. Moreover, although not involved in A28 binding, the N-terminal helical region approximal to the transmembrane part, encompassing
64
RIK
66
,
72
W, and
83
ESDRGR
88
, is also crucial for viral EFC formation and MV infectivity.

IMPORTANCE

Vaccinia virus infection requires virus-cell membrane fusion to complete entry during endocytosis; however, it contains a large viral fusion protein complex of 11 viral proteins that share no structure or sequence homology to all the known viral fusion proteins, including type I, II, and III fusion proteins. It is thus very challenging to investigate how the vaccinia fusion complex works to trigger membrane fusion with host cells. In this study, we crystallized the ectodomain of vaccinia H2 protein, one component of the viral fusion complex. Furthermore, we performed a series of mutational, biochemical, and molecular analyses and identified two surface loops containing
170
LGYSG
174
and
125
RRGTGDAW
132
as the A28-binding region. We also showed that residues in the N-terminal helical region (amino acids 51–90) are also important for H2 function.
Draft genome sequence of
Vibrio lentus
VLO8, recovered from the larval culture of the Chilean scallop (
Argopecten purpuratus
)
Authors: Hurtado Luz , Urtubia Rocío , Concha Christopher , Rodríguez Sergio , Barja Juan L. , Rojas Rodrigo
Published: November 2023

This announcement reports the genome of
Vibrio lentus
VLO8 recovered from the larval culture of Chilean scallop. The genomes of strain VLO8 have two contigs with a total length of 5,499,980 bp, an average G + C content of 44.22%, a total number of protein-coding genes of 6,439, and 170 RNAs.
Deciphering the antigen specificities of antibodies by clustering their complementarity determining region sequences
Authors: Saputri Dianita S. , Ismanto Hendra S. , Nugraha Dendi K. , Xu Zichang , Horiguchi Yasuhiko , Sakakibara Shuhei , Standley Daron M.
Published: November 2023

Recent advances in adaptive immune receptor repertoire sequencing have provided abundant B cell receptor (BCR) sequences under various conditions, including vaccination and disease. However, determining target antigen and epitope specificity of the corresponding antibodies is a major challenge due to their exceptional sequence diversity. Here, we introduce a novel method to cluster antibodies sharing antigenic targets based on their complementarity determining region (CDR) sequences. Using the proposed method, we demonstrate that SARS-CoV-2 spike protein receptor-binding domain (RBD) binders and non-RBD binders from publicly available BCR data were classified correctly, with a cluster purity of 95%. These clusters were then leveraged for annotating unlabeled COVID-19 patient BCR data, enabling the discovery of novel anti-RBD antibodies. We further validated the method by clustering BCR repertoires obtained from single-cell immune profiling of diphtheria-tetanus-pertussis (DTP)-vaccinated donors. Antibody expression and antigen-binding assays demonstrated that the clusters exhibited 96% antigen purity, surpassing the apparent 82% purity achieved by assigning antigens to the same B cells using fluorescently labeled DTP antigen probes. Moreover, antibodies within certain clusters were found to possess neutralizing activity, suggesting that CDR clusters contain epitope-level information. Together, this study offers a simple approach for antigen- and epitope-specific BCR discovery that is reproducible, inexpensive, and applicable to a wide range of antigen targets.

IMPORTANCE

Determining antigen and epitope specificity is an essential step in the discovery of therapeutic antibodies as well as in the analysis adaptive immune responses to disease or vaccination. Despite extensive efforts, deciphering antigen specificity solely from BCR amino acid sequence remains a challenging task, requiring a combination of experimental and computational approaches. Here, we describe and experimentally validate a simple and straightforward approach for grouping antibodies that share antigen and epitope specificities based on their CDR sequence similarity. This approach allows us to identify the specificities of a large number of antibodies whose antigen targets are unknown, using a small fraction of antibodies with well-annotated binding specificities.
Efficacy of combined COVID-19 convalescent plasma with oral RNA-dependent RNA polymerase inhibitor treatment versus neutralizing monoclonal antibody therapy in COVID-19 outpatients: a multi-center, non-inferiority, open-label randomized controlled trial (PlasMab)
Authors: Siripongboonsitti Taweegrit , Nontawong Nuttakant , Tawinprai Kriangkrai , Suptawiwat Ornpreya , Soonklang Kamonwan , Poovorawan Yong , Mahanonda Nithi
Published: November 2023

The effectiveness of neutralizing monoclonal antibodies against emerging variants with spike protein mutations has been limited. Early high-titer convalescent plasma therapy (CPT) tends to be effective and a potential treatment option for COVID-19 outpatient treatment. An open-label, 1:1, randomized controlled trial compared the efficacy of high neutralizing titer CPT with favipiravir (CPT-FPV) versus sotrovimab. The study aimed to evaluate the non-inferiority of CPT-FPV treatment compared to sotrovimab in preventing hospitalization within 14 and 28 days. Among the 136 randomized participants, 68 received CPT-FPV, while 68 received sotrovimab. The study demonstrated that CPT-FPV was non-inferior to sotrovimab in preventing hospitalization within 14 and 28 days. No significant differences between the two treatment arms were observed in emergency room visits, oxygen supplementation, or mortality. Although there were no significant disparities in radiological, virological, or inflammatory marker outcomes, sotrovimab exhibited a more pronounced reduction in IL-6 levels during days 2–5 and lower MCP-1 levels on day 14. High neutralizing titer convalescent plasma and favipiravir demonstrated non-inferior to sotrovimab in preventing hospitalization, emergency room visit, oxygen supplementation, and mortality in mild-to-moderate COVID-19. The evidence may be a choice for treatment for new variants despite the need for further study. (The trial protocol was registered in the Thai clinical trials registry no. 20220319002.)

IMPORTANCE

This pivotal study reveals that high neutralizing titer COVID-19 convalescent plasma therapy (CPT) combined with favipiravir (FPV) is non-inferior to sotrovimab in preventing hospitalization and severe outcomes in outpatients with mild-to-moderate COVID-19 and high-risk comorbidities. It underscores the potential of CPT-FPV as a viable alternative to neutralizing monoclonal antibodies like sotrovimab, especially amid emerging variants with spike protein mutations. The study’s unique approach, comparing a monoclonal antibody with CPT, demonstrates the efficacy of early intervention using high neutralizing antibody titer CPT, even in populations with a significant proportion of elderly patients. These findings are crucial, considering the alternative treatment challenges, especially in resource-limited countries, posed by the rapidly mutating SARS-CoV-2 virus and the need for adaptable therapeutic strategies.