bluuebunny/crossref_metadata_2025 huggingface dataset:
Method of Pointing Temperature Compensation for Deep Space Large Aperture Antenna
Authors: Xiaofei Xu , Yuequan Zhan , Jun Zhang
Published: August 2021

In order to achieve long-distance measurement and control of deep space detectors, increasing the aperture is the most direct means to improve antenna performance. However, the increase in antenna size brings structural instability and is easily affected by external environments such as temperature, gravity, and wind gusts. Aiming at the problem that temperature changes affect the antenna pointing accuracy, this paper designs and implements an antenna pointing temperature compensation model, and conducts data collection and test verification. The results show that the antenna pointing accuracy can be compensated effectively under a large temperature environment by the method proposed in this paper, and the received signal strength is improved.
Research on Design and Mechanism of Sound Insulating Structure Based on Acoustic Metamaterials
Authors: Xue Zhao , Jingbo Zhao , Hong Yao
Published: August 2021

In view of the difficult problems of low-frequency noise reduction, based on the clamping boundary-type acoustic metamaterial theory with negative effective mass density, a structure combining membrane-type and clamping boundary-type is designed, which can realize good sound insulation performance in the low-frequency region, and the theoretical calculation and numerical simulation are in good agreement. At the same time, the transmission property of the structure at zero refractive index and impedance matching is studied. The research suggests that the structure has good low-frequency broadband sound insulation performance, and can achieve high transmission performance of sound waves through structural regulation.
Recycling Mode and Remanufacturing Cost Analysis of Used Automobile Engine Based on System Dynamics
Authors: Shi Junli , Hu Junyu , Jin Zongyi , Ma Yundong , Ma Mingyang , Wang Huaizhi , Ma Qinyi
Published: August 2021

From the three processes of recycling, remanufacturing and remanufacturing product sales, this paper analyses the characteristics of the automobile engine cost. By using the theory of system dynamics method, it establishes system flow diagram of automobile engine recycling and remanufacturing cost under the methods of network recovery and 4S shop recovery, and constructs engine remanufacturing cost model. Taking Shandong heavy-duty automobile diesel engine remanufacturing as an example, the model is simulated and analyzed with Vensim PLE software, and the change trend of engine recovery cost and profit from 2015 to 2035 is analyzed and predicted. The sales revenue, cost and profit of remanufacturing under the two recovery methods are compared and analyzed. Furthermore, the simulation results show that the different selections of engine recovery strategies have significant differences on the economic impact of engine remanufacturing, and the economic analysis can provide a reference for the development decision of engine remanufacturing.
Difference analysis of non-contact planar scroll spring with the same stiffness
Authors: Jiangnan RAN , Tao YANG , Zizhen CAO , Yang XIN , Kun WANG , Chunguang XU
Published: August 2021

In this paper, a set of mathematical models of non-contact planar scroll springs with the same stiffness are established. Based on ABAQUS simulation analysis software, the finite element modeling was carried out, and the modal, torsional stiffness, maximum stress and stress distribution of each plane scroll spring were analyzed. At the same time, the results of finite element analysis (torsional stiffness and maximum stress) are compared with the results of empirical formula, and some experimental data are introduced. The results show that the results of the two methods are basically the same, but there are still some differences. Although the empirical formula is more simple and general, the finite element simulation analysis still has a certain reference significance in the selection and design of spring, especially for the plane scroll spring with high precision mechanical properties.
Corrosion analysis of angle steel used in 500kV transmission tower
Authors: Hao Chen , Yang Guo , Wentao Tian , Xin Qiao , Xiaomeng Tan
Published: August 2021

Transmission tower is the load-bearing structure of high-voltage transmission line, and its stability is very important for the reliable operation of grid equipment. In recent years, the corrosion of transmission towers has become increasingly prominent due to long-term service in the harsh field, which seriously affects its service life. In this paper, the corroded angle steel of high-voltage power tower was studied by different physical and chemical testing methods such as macro inspection, metallographic analysis, mechanical property test, chemical composition analysis, energy spectrum analysisand scanning electron micrograph analysis. The result reveled that the galvanized protective layer of the angle steel was well preserved without corrosion damage, and the corrosion spot on surface of the tower materail was caused by the corrosion of other metal parts nearby and then the rusting outcome flowed with rain water to its surface.
High-power disc laser welding quality detection based on photoelectric sensing system
Authors: Huang Weiwei , You Deyong , Zhang Yanxi , Gao Xiangdong
Published: August 2021

In order to monitor the quality of laser welding in real time, a photoelectric sensor system is designed, which can collect the light radiation signals of the welding area in real time. The signals are converted into voltage signals by the photoelectric sensor and collected by the data acquisition card. Matlab software is used to analyze the power spectrum of the collected data. It is found that visible light and reflected light have similar power spectrum characteristics through experimental analysis, and the number of peaks and peak frequencies of the power spectrum have an obvious relationship with the quality of the weld. The results show that the detection system can effectively monitor welding defects in real time.
Analysis of virtual fatigue life of welding structure of tracked vehicle based on load spectrum
Authors: Bao Ke , Dai Jin , Liu Yue , Zhang Qing
Published: August 2021

Welding has become the main processing method of the supporting structures on tracked vehicles. The accurate evaluation of fatigue life of welding structures is of great significance significant to the reliability of tracked vehicle. The whole analysis process, based on strengthened load spectrum and structural stress method, is proposed in the study to predict the fatigue life of welding structures. Initially, the road-load spectrum of different conditions was obtained by vehicle tests. Then, the data which had been preprocessed were compressed based on pseudo-damage editing. Furthermore, the load spectrums were extrapolated and equivalent to program-loaded spectra according to the non-parametric rain-flow extrapolation method. On the other hand, the finite element model of the welding structure of the tracked vehicle was established to calculate the structural stress at the welding seam
Wellbore characteristics of air drilling with hammer in thick conglomerate and its influence on hole deviation
Authors: Chen Feng , Huo Yonghao , Zhao Haiyi , Wang Wenchang , Di Qinfeng , Wang Yanmin , Chi Jun
Published: August 2021

Air drilling with hammer is generally recognized as an effective drilling method, but the hole obtained in thick conglomerate formation is very irregular, and the control of hole deviation is very difficult. Although many studies have been carried out, the mechanism of this phenomenon has not been found out yet. In this paper, based on the numerical simulation of rock breaking process of air hammer, the influence of the heterogeneity of conglomerate on the wellbore regularity and hole deviation is analyzed. The results show that the direction of the bit will be changed due to the heterogeneous distribution of gravel particles, which make the wellbore with a severely irregular shape. On this basis, the finite element models of BHA in regular and irregular wellbores are established respectively, and the influence of wellbore irregularity on the stress of BHA is analyzed. It can be found the irregular wellbore is easy to form additional fulcrum, shorten the effective swing distance of pendulum bottom hole assembly. The additional fulcrum greatly changes the mechanical characteristics of the BHA, reducing the angle dropping force on bit, or even produce the angle building force.
Thermal Comfort Analysis of Passenger Compartment of a Hybrid Vehicle
Authors: Feng Jiqi , Yan Tingsong , Zhao Kun
Published: August 2021

The internal environment of the passenger compartment directly affects the mental state of the driver and passengers. The research on the thermal comfort of the passenger compartment has become an important topic in the automotive industry. This paper used computational fluid dynamics method to study the thermal environment of the passenger compartment and the thermal comfort of the human body under different air outlets. Predictive mean vote model and equivalent temperature model were used for calculation. The influence of solar radiation on the velocity and temperature field in the passenger compartment was considered in the simulation process, and the correctness of the simulation results was verified by the cooling performance experiment of air conditioning. The results showed that the position of the air outlet had a great influence on the driver’s thermal comfort. When the air outlet was on the driver’s side, the driver’s thermal comfort was the best.
Sensitivity Analysis of Factors Influencing Accelerometer Hysteresis Based on Morris Screening Method
Authors: Ye Kun , Teng Lin , Li Pengfei , Chen Liang
Published: August 2021

Aiming at the fuzzy cognition of the key process parameters that affect the accelerometer hysteresis performance in the assembly and manufacturing process, a sensitivity analysis method for the influencing factors of accelerometer hysteresis based on Morris screening method was proposed in this paper. Firstly, the assembly and manufacturing process parameters and their range of values of core structure pendulum components are analyzed statistically. Secondly, the mean value and variance of the basic factors of each parameter are obtained based on finite element numerical simulation method. The results show that the bonding Angle between the pad I and the pendulum plate and the bonding Angle between the counterweight and the pendulum plate have the greatest influence on the hysteresis performance of the accelerometer. The interaction between the counterweight and the bonding Angle and other parameters is the most nonlinear.
Research on Sparse Code Multiple Access Technology
Authors: Chen Yujie , Ma Caihong
Published: August 2021

As an important port technology in mobile communication, multiple access can effectively improve the number of user access in the communication system. However, the Orthogonal Multiple Access (OMA) technology has been unable to meet the higher requirements of spectrum efficiency and system capacity in the future, so it is of great practical significance to study and design a new multiple access technology. Sparse Code Multiple Access (SCMA), as a new non-orthogonal multiple Access (NOMA) scheme, improves the number of user access and spectrum utilization by superposition of multi-user information on the same time-frequency resource. And it can well adapt to all kinds of new application scenarios in 5G. This paper introduces SCMA technology from four aspects: basic principle, system model, key technology and its combination with other systems.
Motor brush assembly inspection system based on OpenMV vision technology
Authors: Cong Zhang , Hua Zhang
Published: August 2021

Motor brush assembly inspection is an important link in the industrial field. Traditional quality inspection methods have high errors, poor efficiency and low automation. To this end, the OpenMV machine vision module is used, through the MicroPython language, combined with Canny operator and Hough Transform (Hough Transform, Hough) algorithm. A program is designed to collect the image of the motor brush and process the data by itself. After the actual application in the factory, the detection effect is good, and the accuracy rate is more than 90%, which effectively improves the detection efficiency and meets the real-time quality inspection needs of the motor brushes.
Development of Intelligent Wellhead Platform for Rescue Truck-mounted Drilling Rig
Authors: Li Wangnian , Weng Yinsheng , Li Dongsheng , Wang Hejian
Published: August 2021

In view of the low efficiency of rescuing trapped people in coal mine accidents, the factors affecting rapid drilling are analyzed. Through the modular and intelligent technology of rescue vehicle drilling rig, a kind of intelligent wellhead platform drilling tool is developed. The wellhead platform has the functions of automatic levelling and automatic screwing and unloading of drilling tools, and realizes the efficient centering, clamping and automatic screwing and unloading functions of all kinds of diameter drilling tools. The automatic levelling of the intelligent wellhead platform adopts the closed-loop control strategy, the dynamic automatic levelling of the wellhead platform, and the automatic screwing and unloading device adopts program control, which realizes the automatic unloading of drilling tools with one button. The intelligent wellhead platform can be quickly assembled with the main engine, saving drilling auxiliary time, and is of great significance for underground rescue in coal mines.
Application of Hydraulic Control Make-up and Rreak-up Device in Improvement Design of Drilling rig
Authors: Junjie SHAO
Published: August 2021

Tunnel drilling rig is widely used in coal mine gas drainage, hidden disaster detection and other construction. In view of the serious problem of thread wear when loading and unloading drill pipe thread of underground drilling rig in coal mine, a pure hydraulic control device is developed. By adjusting the corresponding angle parameters of the hydraulic control device, two actions of rotary feeding can be realized, and the thread can be loaded and unloaded automatically according to the thread pitch. The design of the device is completed, and the structure is applied to the improved design of ZDY750L and ZDY2-300LM drilling rigs. The matching control of feed and rotation of the two drilling rigs when loading and unloading the drill pipe is realized, which can reduce the wear of the drill pipe thread when the full hydraulic drilling rig is loading and unloading, and provides a new idea and solution for the implementation of the full hydraulic drilling rig automatic loading and unloading.
Designation and Verification of Manned Spacecraft and Cargo Ship Universal Operating Platform for Vacuum Thermal Test Based on Modular Design
Authors: Zheyang Ge , Runze Wang , Jihui Xie , Zhenyue Ren , Chenwei Hong
Published: August 2021

Before the spacecraft vacuum thermal test, the spacecraft needs to be hoisted into the space environment simulator. Due to the high altitude of the spacecraft, a dedicated operating platform is required. The size of the manned spacecraft and the cargo spacecraft are inconsistent, so the existing operating platforms cannot satisfy the operating requirements of both types of spacecraft. In addition, the existing operating platform has poor structural strength and needs to be assembled in the space environment simulator. In order to solve these problems a universal platform is in proposed. This paper adopts modular design method, using analyzing software for modal analysis, instability analysis and overall lifting analysis. It reduce the maintenance, storage, and transportation costs of the operating platform, improve the assembly efficiency of the operating platform and realize the universal design of the operating platform of the manned spacecraft and the cargo spacecraft.
Design of inspiratory linear die-filling system
Authors: Chen Chao , Zhong WenZhen , Yang Chao , Chai YinFu
Published: August 2021

Powder die-filling is an important process in the process of powder pressing. The effect of mold filling directly affects the subsequent pressing process and ultimately affects the quality of products. During the filling process, the air in the die has an obvious effect on the filling behavior, which seriously reduces the filling efficiency of the powder. Aiming at the influence of air in the process of powder filling, a set of inspiratory linear die-filling system was designed. The system is mainly composed of control module and mechanical module, in which the mechanical module includes two parts: filling device and inhalation device. The iron powder filling trial was carried out by using this system. The movement speed of the shoe was set as 250mm/s. It was found that the filling efficiency of the aspirated filling was improved by nearly 30% compared with that of the gravity filling. The results show that the aspirated die-filling can effectively reduce the influence of air on the powder filling behavior, and improve the filling efficiency of the powder die-filling.
Modal analysis and analysis of motor support based on workbench test bench design of motor dynamic shock absorber
Authors: Wang YueMin , Xu Ke , Zhang Qing
Published: August 2021

This article takes the test bench support (hereinafter referred to as the support) as the research object, analyzes its natural frequency, establishes a three-dimensional model of the support through creo, and uses ansys workbench for modal analysis. The motor is an adjustable-speed motor with a maximum speed of 20000r/s and is fixed on the bracket. The rotation excitation frequency of the motor and the natural frequency of the bracket will form resonance in the first 10 steps, so a damping shock absorber is designed to transfer the vibration on the motor to the vibration reduction device, so as to achieve the purpose of eliminating vibration.
Research on Application of Transfer Learning in Equipment Fault Diagnosis
Authors: Tian Xue , Dinghai Wu , Huaiguang Wang
Published: August 2021

In view of the complex and changeable operating conditions of equipment, and the different distribution of measured data, it is difficult to promote the application of fault diagnosis technology. Many scholars have introduced transfer learning to overcome the lack of training data for deep learning by transferring existing data and models in similar domains into the target domain, it has expanded the application of fault diagnosis technology. This paper introduces the related concepts of transfer learning, summarizes the current applications and existing problems of transfer learning in the field of fault diagnosis, and finally puts forward further research directions and suggestions in general detection, real-time detection, etc. The purpose is to better improve equipment support capabilities.
Design of a fully automatic intelligent cooking robot
Authors: zhang Jianbao , Bao Shiping , Luo Bing
Published: August 2021

With the rapid development of Internet of things artificial intelligence, people’s life becomes more and more convenient. Intelligent frying machine has been favored by consumers because of its advantages of saving time and saving time. However, most of the existing market fry machines have the disadvantages of low automation, low quality and complicated operation, but they have not been widely promoted. Therefore, this paper designs an intelligent cooking robot with full automatic, high intelligence and convenient operation. It is based on the Internet of things information technology, and improves the structure, circuit, software and user experience in all aspects. It has the functions of automatic weighing of food materials, intelligent recipe generation, intelligent seasoning precise addition, automatic cooking, voice interaction and other functions. It realizes the full automation, precision and intelligence of the cooking process, and the user experience is good.
Safety risk analysis of Home Automation products
Authors: Luo Hongqi , Liu Xia , Wang Po
Published: August 2021

Home Automation can provide people with safe and comfortable living environment, but due to the defects of related equipment and support technology at different levels, the safety accidents of Home Automation products occur from time to time. By analyzing the composition of Home Automation system, the characteristics of each subsystem and the existing security risks, the risk relationship of each subsystem is analyzed. The risk research status of Home Automation products at home and abroad and the status of standard formulation and revision are compared, so as to provide support for the corresponding theoretical analysis and practical application.
Design and Development of Welding Data Processing System
Authors: Wang Laizhen , Long Bin , Duan Ruibin , Wang Kekuan , Lv Li
Published: August 2021

Through database technology, welding data management technology and automatic analysis storage technology, a management system for welding process monitoring is designed and developed in C# environment, which realizes the integrated automatic management of real-time analysis, processing, storage and uploading of welding data; at the same time, it can make statistical analysis of historical data and generate reports. In addition, the system also has scalability, which provides technical support for the construction of “intelligent pipeline and smart pipe network” in the future.
A stress amplification model to evaluate the stress concentration of tool joint under complex loads
Authors: Chen Feng , Zhao Haiyi , Huo Yonghao , Di Qinfeng , Wang Wenchang , Zhou Xing
Published: August 2021

The more and more severe drilling conditions make the load conditions of tool joint extremely complex. Under the complex load conditions, the stress concentration of tool joint is serious, so failure of tool joint often occur in the oilfield. However, few researchers have studied the stress concentration of tool joint under complex loads. In this paper, the stress distribution of an API tool joint, NC38, was analyzed with 3D elastic-plastic finite element method under complex loads. The stress concentration factors of the tool joint were calculated, and the influence of tensile and bending load on it was analyzed in detail. The results show that the existing model cannot effectively reflect the fact that the stress concentration of tool joint will increase with large tensile load in the crooked hole section. Based on the 3D finite element analysis, a stress amplification model is proposed and used to reflect the failure risk of tool joints under the combined action of axial tension and bending moment. The results show that this model is consistent with the fact that the failure risk of tool joint will increase with large tensile load in the crooked hole section.
Repairability Evaluation of Retired Hot Forging Die Based on Matter-Element Extension Model
Authors: Bin Chen
Published: August 2021

Hot forging die is one of the important tools for machining. Because of its bad working environment, it is prone to lose its effect. Repairing the retired hot forging die can reduce the production cost and prolong the service life of the die, which has good economic benefits. In view of the complexity and uncertainty of hot forging die repair process, and the complexity and uncertainty of hot forging die repair process, this paper constructed the evaluation indexes of technical feasibility, economic feasibility, environmental feasibility, life-span feasibility and time-effectiveness feasibility, and comprehensively uses AHP and matter-element extension model to evaluate the repairability of retired hot forging dies. The rationality of this method was verified by the repairability evaluation of the hot forging die of a retired automobile steering knuckle.
Research on Multi-Agent Modeling Method of Space Based Network Information System
Authors: Lai Jiazhe , Yu Haoze , Zhang Zhening
Published: August 2021

Space based information network system is a network system composed of spacecraft and spacecraft, which plays an immeasurable role in commercial and military, so it is very important to carry out simulation research on it. In this paper, the idea of Multi-Agent modeling is applied to study the simulation modeling of space-based network information system. This paper first introduces the space-based network information architecture, Multi-Agent system and RepastHPC, a Multi-Agent high-performance computing simulation toolbox. The simulation example is Starlink’s information support capability under AIM-260 “A aims and directs B to strike” fire attack mode, and the process of message Starlink transmission is mainly studied. In this paper, the space-based network information system is abstracted into route agent and sat agent, the decision-making method is given for each behavior, and a feasible Multi-Agent system is established. The simulation experiment of information transmission is carried out on RepastHPC platform, and the feasibility of applying Multi-Agent system to space-based network information system is verified.
Numerical Simulation of Optimizing Plating Uniformity of Interconnect Circuits on Printed Circuit Boards
Authors: Xiang Jing , Chen Panfeng , Wang Yingjie , Zeng Chong , Yang Wenyao , Li Jie , Xu Yonggang
Published: August 2021

Based on the finite element method, the interconnection circuit models with different pattern designs were established and plating copper circuits were simulated to obtain the plating uniformity. Meanwhile, the influence of insulating shield, auxiliary cathode and the distance between anode and cathode (DAC) on the plating uniformity is studied to provide theoretical guidance for improving the uniformity of electroplating copper at actual production. Compared with other pattern designs, the circuit with a pattern design area ratio of 20% has the best plating uniformity under the initial conditions. The increase in the auxiliary cathode width and the decrease the aperture of insulating shield and DAC can improve the electroplating uniformity of circuit.
Nitsche’s method for Navier–Stokes equations with slip boundary conditions
Authors: Gjerde Ingeborg , Scott L.
Published: August 2021

We formulate Nitsche’s method to implement slip boundary conditions for flow problems in domains with curved boundaries. The slip boundary condition, often referred to as the Navier friction condition, is critical for understanding and simulating a wide range of phenomena such as turbulence, droplet spread and flow through microdevices. In this work, we highlight the role of the approximation of the normal and tangent vector. In particular, we show that using the normal and tangent vectors with respect to the discretized domainΩh\Omega _h, denotednh\mathbf {n}_handτh\boldsymbol {\tau }_h, is suboptimal. Taking instead a projection of the normal and tangent vectors with respect toΩ\Omega, denotednπ\mathbf {n}_\piandτπ\boldsymbol {\tau }_\pi, gives the best convergence rate that can be expected for a polygonal approximation of a curved boundary.

Finally we also prove that, if you use instead the exact slip withnh\mathbf {n}_handτh\boldsymbol {\tau }_h, the approximation converges to the wrong solution. This is known as the Babuška-Sapondzhyan Paradox. Thus Nitsche’s method relaxes the slip condition and avoids the lack of convergence.
Crime Victims, Immigrants And Social Welfare: Creating The Racialized Other In Sweden
Authors: Branteryd Fia , Gallo Carina , Brown Elizabeth , Svensson Kerstin
Published: August 2021

This study explores the role of immigration and racialization in creating the first Swedish victim support centre in the early 1980s. The study is based on a qualitative content analysis of the archives of Victim Support Södertälje, the first lasting Swedish victim support centre, from 1983 to 1990. While many of the centre’s activities focused on crime prevention, it defined crime and victimization as the province of immigrant communities in Södertälje, and, notably, as outside—and aberrant from—the imagined racial community of Sweden. Thus, victim support centres were one of the mechanisms to continue to defend the ideals of the Swedish welfare state, but to do so in ways that prevented incursions within Swedish racial homogeneity from the outside.
Short-term outcomes of a multicentre randomized clinical trial comparing laparoscopic pylorus-preserving gastrectomy with laparoscopic distal gastrectomy for gastric cancer (the KLASS-04 trial)
Authors: Park D. J. , Kim Y.-W. , Yang H.-K. , Ryu K. W. , Han S.-U. , Kim H.-H. , Hyung W.-J. , Park J. H. , Suh Y.-S. , Kwon O. K. , Yoon H. M. , Kim W. , Park Y.-K. , Kong S.-H , Ahn S. H. , Lee H.-J.
Published: August 2021

Background

There remain concerns about the safety and functional benefit of laparoscopic pylorus-preserving gastrectomy (LPPG) compared with laparoscopic distal gastrectomy (LDG). This study evaluated short-term outcomes of a randomized clinical trial (RCT) comparing LPPG with LDG for gastric cancer.

Methods

The Korean Laparoendoscopic Gastrointestinal Surgery Study (KLASS)-04 trial was an investigator-initiated, open-label, parallel-assigned, superiority, multicentre RCT in Korea. Patients with cT1N0M0 cancer located in the middle third of the stomach at least 5 cm from the pylorus were randomized to undergo LPPG or LDG. Participants, care givers and those assessing the outcomes were not blinded to group assignment. Outcomes were 30-day postoperative morbidity rate and death at 90 days.

Results

Some 256 patients from nine institutions were randomized (LPPG 129 patients, LDG 127 patients) between July 2015 and July 2017 and outcomes for 253 patients were analysed. Postoperative complications within 30 days were seen in 19.3 and 15.5 per cent in the LPPG and LDG groups respectively (P = 0·419). Postoperative pyloric stenosis was observed in nine (7.2 per cent) and two (1·5 per cent) patients in the LPPG and LDG groups (P = 0·026) respectively. In multivariable analysis higher BMI was a risk factor for postoperative complications (odds ratio 1·17, 95 per cent c.i. 1·04 to 1·32; P = 0·011). Death at 90 days was zero in both groups.

Conclusion

Postoperative complications and mortality was comparable in patients undergoing LPPG and LDG. Registration number: NCT02595086 (http://www.clinicaltrials.gov).
Interactome screening ofC9orf72dipeptide repeats reveals VCP sequestration and functional impairment by polyGA
Authors: Božič Janja , Motaln Helena , Janež Anja Pucer , Markič Lara , Tripathi Priyanka , Yamoah Alfred , Aronica Eleonora , Lee Youn-Bok , Heilig Raphael , Fischer Roman , Thompson Andrew J , Goswami Anand , Rogelj Boris
Published: August 2021

Repeat expansions in the C9orf72 gene are a common cause of amyotrophic lateral sclerosis and frontotemporal lobar degeneration, two devastating neurodegenerative disorders. One of the proposed mechanisms of GGGGCC repeat expansion is their translation into non-canonical dipeptide repeats, which can then accumulate as aggregates and contribute to these pathologies. There are five different dipeptide repeat proteins (polyGA, polyGR, polyPR, polyPA and polyGP), some of which are known to be neurotoxic.

In the present study, we used BioID2 proximity labelling to identify the interactomes of all five dipeptide repeat proteins consisting of 125 repeats each. We identified 113 interacting partners for polyGR, 90 for polyGA, 106 for polyPR, 25 for polyPA and 27 for polyGP. Gene Ontology enrichment analysis of the proteomic data revealed that these target interaction partners are involved in a variety of functions, including protein translation, signal transduction pathways, protein catabolic processes, amide metabolic processes and RNA-binding. Using autopsy brain tissue from patients with C9orf72 expansion complemented with cell culture analysis, we evaluated the interactions between polyGA and valosin containing protein (VCP). Functional analysis of this interaction revealed sequestration of VCP with polyGA aggregates, altering levels of soluble valosin-containing protein. VCP also functions in autophagy processes, and consistent with this, we observed altered autophagy in cells expressing polyGA. We also observed altered co-localization of polyGA aggregates and p62 in cells depleted of VCP.

All together, these data suggest that sequestration of VCP with polyGA aggregates contributes to the loss of VCP function, and consequently to alterations in autophagy processes in C9orf72 expansion disorders.
Functional Inhibitory Connections Modulate the Electrophysiological Activity Patterns of Cortical-Hippocampal Ensembles
Authors: Brofiga Martina , Pisano Marietta , Tedesco Mariateresa , Boccaccio Anna , Massobrio Paolo
Published: August 2021

The brain is a complex organ composed of billions of neurons connected through excitatory and inhibitory synapses. Its structure reveals a modular topological organization, where neurons are arranged in interconnected assemblies. The generated patterns of electrophysiological activity are shaped by two main factors: network heterogeneity and the topological properties of the underlying connectivity that strongly push the dynamics toward different brain-states. In this work, we exploited an innovative polymeric structure coupled to Micro-Electrode Arrays (MEAs) to recreate in vitro heterogeneous interconnected (modular) neuronal networks made up of cortical and hippocampal neurons. We investigated the propagation of spike sequences between the two interconnected subpopulations during the networks’ development, correlating functional and structural connectivity to dynamics. The simultaneous presence of two neuronal types shaped the features of the functional connections (excitation vs. inhibition), orchestrating the emerging patterns of electrophysiological activity. In particular, we found that hippocampal neurons mostly project inhibitory connections toward the cortical counterpart modulating the temporal scale of the population events (network bursts). In contrast, cortical neurons establish a larger amount of intrapopulation connections. Moreover, we proved topological properties such as small-worldness, degree distribution, and modularity of neuronal assemblies were favored by the physical environment where networks developed and matured.
Determination of Saccharides in Honey Using Supercritical Fluid Chromatography Coupled with Single Quadrupole Mass Spectrometry
Authors: Huang Yang , Jiang Zhengjin
Published: August 2021

Saccharides are one of the most important biomoleculars in the world, which are responsible for various roles in living organisms. In this work, a combined use of mass spectrometry (MS) together with supercritical fluid chromatography (SFC) was applied for the separation of eight saccharides. A satisfactory separation was achieved within 15 min on a Unitary Diol column using 10 mM ammonium acetate in methanol as mobile phase additive at a temperature of 60°C. Compared to liquid chromatography–MS (LC–MS), the SFC–MS presented faster running time and better selectivity. The SFC–MS was validated and applied to the analysis of three saccharides (fructose, glucose and sucrose) present in different honey samples. The limits of detection (LODs) and limits of quantification (LOQs) of SFC–MS method for fructose, glucose and sucrose were 5.2, 4.5, 7.4 μg/mL and 17.2, 14.9, 24.1 μg/mL, respectively. The relative standard deviations for intrabatch and interbatch precision were <2.5% and the recoveries ranged from 97.6% to 103.1% for three concentration levels. The values of LODs and LOQs using SFC–MS method were lower (1.5–2.4-fold) than using LC–MS method. The results demonstrated the potential of SFC–MS for fast and sensitive determination of saccharides in honey.
Do you feel itchy? A guide towards diagnosis and measurement of chronic kidney disease-associated pruritus in dialysis patients
Authors: Manenti Lucio , Leuci Emanuela
Published: August 2021

Chronic kidney disease-associated pruritus (CKD-aP) is a potentially distressing condition that affects a significant proportion of patients with end-stage kidney disease undergoing dialysis. CKD-aP may lead to worsening of patients’ physical and mental health-related quality of life (HRQoL) and has also been linked with worse clinical outcomes, including increased mortality. Despite these detrimental effects, evidence from real-world studies shows that CKD-aP still remains overlooked by nephrologists and underreported by patients in clinical practice. Itch is subjective and therefore its diagnosis is often dependent on patients reporting this symptom. There is an opportunity to reduce the burden of CKD-aP on dialysis patients by increasing awareness about this condition and the availability of effective treatments. It is particularly important that nephrologists and other healthcare providers routinely ask their patients if they are experiencing itch. The differential diagnosis of CKD-aP requires a step-by-step identification and exclusion of possible alternative or concomitant causes of itch. Several simple validated self-reported assessment scales are available to evaluate the presence and severity of itch in a time-efficient manner, making them suitable for use in everyday clinical practice. The impact of CKD-aP on haemodialysis patients’ HRQoL should also be assessed on a regular basis. This review provides a comprehensive overview of the differential diagnosis of CKD-aP and the diagnostic tools that are available to identify itch and quantify its severity and impact on patient HRQoL. A suggested algorithm to guide the screening, diagnosis and assessment of CKD-aP among dialysis patients in real-world practice is provided.
Novel biomarker-driven prognostic models to predict morbidity and mortality in chronic heart failure: the EMPEROR-Reduced trial
Authors: Pocock Stuart J , Ferreira João Pedro , Gregson John , Anker Stefan D , Butler Javed , Filippatos Gerasimos , Gollop Nicholas D , Iwata Tomoko , Brueckmann Martina , Januzzi James L , Voors Adriaan A , Zannad Faiez , Packer Milton
Published: August 2021

Aims

The aim of this study was to generate a biomarker-driven prognostic tool for patients with chronic HFrEF. Circulating levels of N-terminal pro B-type natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (hs-cTnT) each have a marked positive relationship with adverse outcomes in heart failure with reduced ejection fraction (HFrEF). A risk model incorporating biomarkers and clinical variables has not been validated in contemporary heart failure (HF) trials.

Methods and results

In EMPEROR-Reduced, 33 candidate variables were pre-selected. Multivariable Cox regression models were developed using stepwise selection for: (i) the primary composite outcome of HF hospitalization or cardiovascular death, (ii) all-cause death, and (iii) cardiovascular mortality. A total of 3730 patients were followed up for a median of 16 months, 823 (22%) patients had a primary outcome and 515 (14%) patients died, of whom 389 (10%) died from a cardiovascular cause. NT-proBNP and hs-cTnT were the dominant predictors of the primary outcome, and in addition, a shorter time since last HF hospitalization, longer time since HF diagnosis, lower systolic blood pressure, New York Heart Association (NYHA) Class III or IV, higher heart rate and peripheral oedema were key predictors (eight variables in total, all P < 0.001). The primary outcome risk score discriminated well (c-statistic = 0.73), with patients in the top 10th of risk having an event rate >9 times higher than those in the bottom 10th. Empagliflozin benefitted patients across risk levels for the primary outcome. NT-proBNP and hs-cTnT were also the dominant predictors of all-cause and cardiovascular mortality, followed by NYHA Class III or IV and ischaemic aetiology (four variables in total, all P < 0.001). The mortality risk model presented good event discrimination for all-cause and cardiovascular mortality (c-statistic = 0.69 for both). These simple models were externally validated in the BIOSTAT-CHF study, achieving similar c-statistics.

Conclusions

The combination of NT-proBNP and hs-cTnT with a small number of readily available clinical variables provides prognostic assessment for patients with HFrEF. This predictive tool kit can be easily implemented for routine clinical use.
The use of remote monitoring of cardiac implantable devices during the COVID-19 pandemic: an EHRA physician survey
Authors: Simovic Stefan , Providencia Rui , Barra Sergio , Kircanski Bratislav , Guerra Jose M , Conte Giulio , Duncker David , Marijon Eloi , Anic Ante , Boveda Serge
Published: August 2021

It is unclear to what extent the COVID-19 pandemic has influenced the use of remote monitoring (RM) of cardiac implantable electronic devices (CIEDs). The present physician-based European Heart Rhythm Association (EHRA) survey aimed to assess the influence of the COVID-19 pandemic on RM of CIEDs among EHRA members and how it changed the current practice. The survey comprised 27 questions focusing on RM use before and during the pandemic. Questions focused on the impact of COVID-19 on the frequency of in-office visits, data filtering, reasons for initiating in-person visits, underutilization of RM during COVID-19, and RM reimbursement. A total of 160 participants from 28 countries completed the survey. Compared to the pre-pandemic period, there was a significant increase in the use of RM in patients with pacemakers (PMs) and implantable loop recorders (ILRs) during the COVID-19 pandemic (PM 24.2 vs. 39.9%, P = 0.002; ILRs 61.5 vs. 73.5%, P = 0.028), while there was a trend towards higher utilization of RM for cardiac resynchronization therapy-pacemaker (CRT-P) devices during the pandemic (44.5 vs. 55%, P = 0.063). The use of RM with implantable cardioverter-defibrillators (ICDs) and CRT-defibrillator (CRT-D) did not significantly change during the pandemic (ICD 65.2 vs. 69.6%, P = 0.408; CRT-D 65.2 vs. 68.8%, P = 0.513). The frequency of in-office visits was significantly lower during the pandemic (P < 0.001). Nearly two-thirds of participants (57 out of 87 respondents), established new RM connections for CIEDs implanted before the pandemic with 33.3% (n = 29) delivering RM transmitters to the patient’s home address, and the remaining 32.1% (n = 28) activating RM connections during an in-office visit. The results of this survey suggest that the crisis caused by COVID-19 has led to a significant increase in the use of RM of CIEDs.
Docosahexaenoic acid normalizes QT interval in long QT type 2 transgenic rabbit models in a genotype-specific fashion
Authors: Castiglione Alessandro , Hornyik Tibor , Wülfers Eike M , Giammarino Lucilla , Edler Iask , Jowais Jessica J , Rieder Marina , Perez-Feliz Stefanie , Koren Gideon , Bősze Zsuzsanna , Varró András , Zehender Manfred , Brunner Michael , Bode Christoph , Liin Sara I , Larsson Hans Peter , Baczkó István , Odening Katja E
Published: August 2021

Aim

Long QT syndrome (LQTS) is a cardiac channelopathy predisposing to ventricular arrhythmias and sudden cardiac death. Since current therapies often fail to prevent arrhythmic events in certain LQTS subtypes, new therapeutic strategies are needed. Docosahexaenoic acid (DHA) is a polyunsaturated fatty acid, which enhances the repolarizing IKs current.

Methods and results

We investigated the effects of DHA in wild type (WT) and transgenic long QT Type 1 (LQT1; loss of IKs), LQT2 (loss of IKr), LQT5 (reduction of IKs), and LQT2–5 (loss of IKr and reduction of IKs) rabbits. In vivo ECGs were recorded at baseline and after 10 µM/kg DHA to assess changes in heart-rate corrected QT (QTc) and short-term variability of QT (STVQT). Ex vivo monophasic action potentials were recorded in Langendorff-perfused rabbit hearts, and action potential duration (APD75) and triangulation were assessed. Docosahexaenoic acid significantly shortened QTc in vivo only in WT and LQT2 rabbits, in which both α- and β-subunits of IKs-conducting channels are functionally intact. In LQT2, this led to a normalization of QTc and of its short-term variability. Docosahexaenoic acid had no effect on QTc in LQT1, LQT5, and LQT2–5. Similarly, ex vivo, DHA shortened APD75 in WT and normalized it in LQT2, and additionally decreased AP triangulation in LQT2.

Conclusions

Docosahexaenoic acid exerts a genotype-specific beneficial shortening/normalizing effect on QTc and APD75 and reduces pro-arrhythmia markers STVQT and AP triangulation through activation of IKs in LQT2 rabbits but has no effects if either α- or β-subunits to IKs are functionally impaired. Docosahexaenoic acid could represent a new genotype-specific therapy in LQT2.
Three-dimensional inversion for sparse potential data using first-order system least squares with application to gravity anomalies in Western Queensland
Authors: Codd A L , Gross L
Published: August 2021

We present an inversion algorithm tailored for point gravity data. As the data are from multiple surveys, it is inconsistent with regards to spacing and accuracy. An algorithm design objective is the exact placement of gravity observations to ensure no interpolation of the data is needed prior to any inversion. This is accommodated by discretization using an unstructured tetrahedral finite-element mesh for both gravity and density with mesh nodes located at all observation points and a first-order system least-squares (FOSLS) formulation for the gravity modelling equations. Regularization follows the Bayesian framework where we use a differential operator approximation of an exponential covariance kernel, avoiding the usual requirement of inverting large dense covariance matrices. Rather than using higher order basis functions with continuous derivatives across element faces, regularization is also implemented with a FOSLS formulation using vector-valued property function (density and its gradient). Minimization of the cost function, comprised of data misfit and regularization, is achieved via a Lagrange multiplier method with the minimum of the gravity FOSLS functional as a constraint. The Lagrange variations are combined into a single equation for the property function and solved using an integral form of the pre-conditioned conjugate gradient method (I-PCG). The diagonal entries of the regularization operator are used as the pre-conditioner to minimize computational costs and memory requirements. Discretization of the differential operators with the finite-element method (FEM) results in matrix systems that are solved with smoothed aggregation algebraic multigrid pre-conditioned conjugate gradient (AMG-PCG). After their initial setup, the AMG-PCG operators and coarse grid solvers are reused in each iteration step, further reducing computation time. The algorithm is tested on data from 23 surveys with a total of 6519 observation points in the Mt Isa–Cloncurry region in north–west Queensland, Australia. The mesh had about 2.5 million vertices and 16.5 million cells. A synthetic case was also tested using the same mesh and error measures for localized concentrations of high and low densities. The inversion results for different parameters are compared to each other as well as to lower order smoothing. Final inversion results are shown with and without depth weighting and compared to previous geological studies for the Mt Isa–Cloncurry region.