bluuebunny/crossref_metadata_2025 huggingface dataset:
A Method of Assembling Clearance Measuring of Oil Film Bearing in Tandem Cold Mill
Authors: Sun Bo , Liu Chuanjian , Zhou Weimin , Xu Zhan , Cao Heng
Published: June 2024

In order to reduce the certain number of oil film bearing burning accident, this paper proposes a novel method used to test static pressure pipes and measure the assembling clearance between sleeve and bush inside the bearing. On account of the theory of lubrication and the working mechanism for oil film bearing, through the development of a new set of hydrostatic oil supply system and test platform, provide the static supporting pressure and the disassembling and locking pressure. And based on this method, the assembling clearance measuring was carried out. The results show that the proposed measuring method has the ability to support the disassembling and assembling process of the oil film bearing. In addition, this method provides an important basis for the engineers of cold rolling mill on site to adjust the assembling clearance of oil film bearing. The application of this method effectively reduces the online burning accidents of the oil film bearing.
Research on Equivalent Wind Load Spectrum Acquisition and Remaining Fatigue Strength Method of Double Active Arm Type Holding Pole
Authors: Liu Wenwu , Zhang Hongsheng , Lu Nianli
Published: June 2024

In order to study the wind load fatigue residual strength in in-service holding poles for preventing disasters, and improving load-bearing capacity reliability. Firstly, using the Davenport wind speed spectrum to simulate the wind speed, it will be the input load of the finite element dynamics model of the 2 × 40 kN double active arm type holding pole (DAATHP). The stress time history curve at the welding section of the main chord at the bottom of the tower shaft is obtained at the working condition with the wind angle of 0°, 45°, 90°, and 135°. The rain flow counting method derives the statistical characteristics of the mean, amplitude, and frequency of stress at four wind angles. Secondly, the frequency of wind load under four wind angles is extended, and the synthesized fatigue load spectrum is used as the equivalent wind load spectrum. Finally, the Paris-Eadogan equation is used to derive the calculation formula of fatigue residual strength of the main chord at the bottom of the tower shaft, and the functional function of the main chord is established and then the failure probability formula is derived by combining the equivalent wind load spectrum. It is found that, compared with the ANSYS calculation results, the error of the predicted stress spectrum of the proposed method is minor, only 7.95%. It is verified that the proposed method can efficiently obtain the equivalent load spectrum of the DAATHP. The results indicate that it is feasible and practical to apply the proposed method to calculate the remaining fatigue life of the DAATHP.
A Study on Weighting Factors in Cost Function of Model Predictive Control Algorithms
Authors: You Zhou , Bian Yongming , Ding Zhangjie , Chen Li
Published: June 2024

With the growing emphasis on environmental protection, the engineering construction industry is facing new demands. The widespread electrification of construction machinery has emerged as an inevitable trend. To align with this trend, this paper conducts research on the model predictive control algorithm (MPC) applied to permanent magnet synchronous motors (PMSM). The MPC algorithm primarily consists of the motor’s mathematical model and the cost function. This study focuses on analyzing the weight factor within the cost function. The spectrum of weight factor combinations concerning the dq-axis current is formulated across a broad range of intervals. The algorithm’s performance is assessed under various weight factors using experimental data from three-phase current operation, motor torque, rotational speed, and other parameters. Ultimately, a novel evaluation function is proposed in this study to quantitatively assess the algorithm’s performance across various combinations. The process involves identifying the optimal combination of weight factors for the cost function. This effort contributes significantly to establishing a robust groundwork for the general electrification of construction machinery.
Multidisciplinary Design Optimization of Excavator Positive Flow Control System
Authors: Chen Yuanliu , Wang Anlin , Li Xiaotian
Published: June 2024

Due to the obstacle to the global optimal solution through the conventional sequential design, the multidisciplinary design optimization (MDO) of an excavator positive flow control system was carried out with hydraulic components and controller programs as design objects simultaneously. The positive flow control system model was established on the basis of bench and field tests to describe the coupling relationship among different subsystems. The comprehensive performance function was proposed and the MDO was carried out with the multiway valve’s throttling characteristics, positive flow control parameters and spool geometries as design variables. Compared with the sequential design that only the control parameters were adjusted, the MDO searched a wider design space. The comprehensive working performance has been improved with the MDO of an excavator’s swing system, which is an example for forward designs of other complicated electro-mechanical-hydraulic systems.
Research on Accelerated Degradation Test and Reliability Evaluation Method for Hydraulic Pumps Based on Parallel Energy Saving
Authors: Qi Jianjun , Chen Shaojia , Wang Dongfeng , Wang Liqin , Guo Rui
Published: June 2024

Hydraulic pump is a product with high reliability and long-life, there exist many urgent problems like long test period, high cost and a larger power consumption in the reliability evaluation method of pump. A new kind of reliability test bench is built combined with parallel power-saving design concept, which based on principles of energy saving and power recycle. Multi-pumps reliability accelerated degradation test is achieved by applying step stress on the pump under test. Volumetric efficiency is selected as performance degradation evaluating index, the degradation of whose is much closed to real physics model. The accretion model for hydraulic pump reliability test is built based on inverse moment estimation method, by which hydraulic pump reliability level under different stress conditions is given. In the meantime, the method of concurrent accelerated degradation testing can serve as references of other core hydraulic components.
A Visual Detection Method for Train Couplers Based on YOLOv8 Model
Authors: Zhao Wenning , Yao Xin , Wang Bixin , Ding Jiayi , Li Jialu , Zhang Xiong , Wan Shuting , Zhao Jingyi , Guo Rui , Cai Wei
Published: June 2024

Accurately identifying the coupler operating handle during the operation of the hook-picking robot has a significant impact on production activities. This article is based on the YOLOv8 model. Due to the limited variety of on-site coupler operating handles and working environment, it is difficult to ensure the richness of image categories in the dataset. Before the experiment, a series of expansion operations were performed on the dataset, such as rotation, translation, and brightness adjustment. Use the expanded images to simulate the images detected by the hook-picking robot in harsh environments. This model performs feature extraction and target recognition on the expanded coupler handle dataset, thereby achieving recognition of the coupler handle. The experimental results show that the accuracy of the model for the coupler handle in complex environments is 98.8%, which effectively reduces the time required for training and testing. Compared with the commonly used SSD300 model and YOLOv4Tiny model, it not only has higher accuracy, but also shows obvious advantages in parameter quantity, weight file size, and other aspects, which can be well deployed in actual production.
Finite Element Simulation of Loss Stroke Phenomenon of Shock Absorber Based on Fluid Structure Interaction
Authors: Yu Zhen-huan , Zhang Na
Published: June 2024

To provide a design reference with guaranteed performance for vehicle shock absorbers, the loss stroke mechanism is studied in this paper based on fluid–structure interaction (FSI) numerical method. According to the parametric model of cavitation mechanism and by applying fluid–structure interaction (FSI) numerical methods, the structural and fluid finite element mesh shock absorber models with high precision are both established. Furthermore, simulations for the proposed models are carried out based on ADINA software. By analyzing the simulation results, the specific position and the distribution of loss stoke, and the difference of cavitation phenomenon under diverse shock absorber loading speeds are revealed. The results indicate that cavitation of the shock absorber primarily centers around the shock absorber valve system, and this phenomenon becomes increasingly pronounced as the piston speed rises. Moreover, the cavitation effect is higher apparent when the shock absorber oil possesses higher viscosity. These findings offer valuable insights for the design and implementation of measures aimed at preventing performance distortion in shock absorbers.
Research on TBM Disc Cutter Wear Prediction Based on CSM Model
Authors: Wang He , Wei Junkun , Yan Guangyu , Zhao Haigen , Xu Jianing
Published: June 2024

The wear of disc cutters significantly impacts the efficiency and cost of TBM operations. In this study, we established a calculation model for radial wear based on the CSM formula and abrasive wear mechanisms. Experimental validation of the wear mechanism confirmed that abrasive wear is the primary mechanism responsible for disc cutter wear. The predictive model was subjected to engineering validation, where the calculated values from the model were compared and analyzed against actual on-site measurements. This validation process confirmed the accuracy and applicability of the model.
Fatigue Life Assessment of Ship Hatch Corner Based on Hot Spot Stress Method
Authors: Qiao Langhao , Yan Renjun , Qiu Yu
Published: June 2024

The hatch corner of ship is the most prone area for stress concentration, which makes the fatigue problem of hatch corner particularly serious, and becomes a position that is easily damaged. Firstly, the hot spot stress method based on surface extrapolation is introduced, and the hatch corner of a bulk carrier is selected as the research object, the scale model test is designed and carried out, the finite element model is established, and the parameters of the corner form and different transition radii are analyzed. The CCS calculation specification evaluates the fatigue strength of hatch corner, and compares the test results with the finite element calculation results. The results show that the hot spot stress method has good adaptability to the fatigue assessment of hatch corner, and the fatigue strength evaluation of hatch corner needs to select the corresponding S–N curve according to the position of the maximum hot spot stress. The form of corner and the increase of transition radius are of great significance for alleviating stress concentration effect and improving fatigue life of corner, which provides reference for fatigue resistance and optimal design of hatch corner structure.
Research on Dynamic Simulation of Crane Movable Pulley System with Defects
Authors: Li Shuo , Zhang Hongsheng , Wang Xiangxiang
Published: June 2024

The movable pulley block failure can lead to catastrophic crane accidents, so the dynamic performance of a defective movable pulley block system is essential. Based on ANSYS contact analysis through APDL command, a pulley block simulation platform is developed, which can be used for dynamic analysis of defective pulley systems. Firstly, a parameterized 2D contact model is established and validated through static analysis. Then, dynamic simulation analysis for the intact pulley block under two working conditions is performed: lifting from the ground and sudden unloading. Finally, COMBIN 37 is used as a defective element, and dynamic simulations are analyzed for the faulty pulley system with hook or wire rope rupture. The analysis results show that the longer the unloading time and the shorter the wire rope length will lead to a minor impact under hook rupture and sudden unloading conditions. Meanwhile, if the unloading time is consistent, the dynamic analysis of the intact pulley block under sudden unloading and defective pulley block with hook rupture are equivalent. It is worth noting that when the steel wire ropes on both sides of the moving pulley break simultaneously in a defective system, it will cause a more significant horizontal impact force. This study demonstrates that ANSYS contact analysis with COMBIN 37 as the defective element can accurately and efficiently apply the dynamic simulation of a crane movable pulley system with defects.
Research on Characteristics of Three-Chamber Hydraulic Cylinder Driving Loader Boom
Authors: Zhu Huidian , Feng Jiangjiang , Yang Jing
Published: June 2024

When the loader boom is lifted and lowered, the hydraulic pump operates at high peak power levels. In this process, the hydraulic valve port dissipates the gravitational potential energy of the boom. Consequently, the dissipated energy is converted into thermal energy, resulting in elevated hydraulic oil temperature and reduced energy efficiency. This paper proposes a gravitational potential energy recovery system based on three-chamber cylinder and a hydraulic accumulator. The system utilizes the hydraulic accumulator to balance the weight of the loading boom and achieve energy recovery for the boom. The co-simulation model of wheel loader based on the three-chamber cylinder was built in SimulationX, then the energy consumption was analyzed under two kinds of typical operating modes. The simulation results illustrate that when the initial pressures of accumulators are 6 and 8 MPa with heavy-load and without load, the system has the highest energy utilization rate. By establishing a loader prototype and investigating the operating characteristics and energy efficiency of the boom driven by a two-chamber cylinder and a three-chamber cylinder, the experimental results illustrate that the new system operates smoothly, reducing energy consumption by 39.24% and peak power by 27.41%.
Experimental Study on the Cohesive Model of Steel-Carbon Fiber Reinforced Plastic Interface by Laser Treatment
Authors: Teng Hao , Wan Hailang , Min Junying
Published: June 2024

The interfacial bonding performance between steel and CFRP significantly influences the mechanical properties of steel-CFRP hybrid structures. Surface treatment is commonly employed to enhance the bonding interface of steel-CFRP. Laser surface treatment is particularly advantageous due to its high efficiency, automatic production capabilities, and widespread use in enhancing interfacial bonding performance. However, little attention has been given to the impact of laser surface treatment on the property parameters that describe the cohesive mode's mechanical behavior at the steel-CFRP interface. This study examined the cohesive zone modes of both original and laser-treated steel-CFRP joints through a double lap shear test following ASTM D3528-96 (2016) standards. Non-contact strain measurement was conducted using 3D digital image correlation techniques. The analysis indicates that the bilinear cohesive model effectively describes the mechanical behavior of the steel-CFRP interface. Laser surface treatment resulted in a respective increase of 83.8% in maximum shear strength, 111.6% in the relative slip corresponding to maximum shear strength and 116.8% in maximum relative slip. Consequently, this study showcases the efficacy of laser surface treatment in improving the mechanical performance at the steel-CFRP interface while quantitatively assessing these improvements through performance parameters within the cohesive zone model.
Study on Blast Resistance of Armored Steel Welded Joint Structures
Authors: Wu Song , Zhang Ming , Zhou Yunbo
Published: June 2024

In order to study the anti-detonation performance of welded joint structure of armored steel, the finite element analysis of welded joint structure under explosion impact was carried out by using material assignment method and structured ALE algorithm (S-ALE), and the accuracy of the model was verified by explosion impact test. The central deformation and failure form of each weld structure under different equivalent loads of a single explosion are studied. Repeated explosive loading of weld structure based on complete restart technology; The cumulative analysis of plastic deformation of weld structure under multiple explosions is realized, and the relationship between central deformation and explosion times and explosion equivalent is obtained.
Aerodynamic Characterization of a Ballistic-Correction Bullet
Authors: Zhang Hongyue , Wu Zhilin
Published: June 2024

Obtaining the aerodynamic parameters of a ballistic-correction bullet is crucial for improving ballistic correction efficiency and enhancing shooting accuracy. In this study, a numerical simulation method is utilized to analyze and calculate the aerodynamic characteristics of the bullet. The focus is on investigating the changes in aerodynamic parameters when the rudder wings are in both unexpanded and expanded states, as well as analyzing the impact of deflection angles on the bullet's aerodynamic characteristics. The simulation results demonstrate that the bullet exhibits favorable aerodynamic performance and static stability when the rudder wings are unexpanded, leading to improved ballistic correction efficiency during flight. Moreover, the results indicate that in the expanded state of the rudder wings, increasing the deflection angle enhances the impact on the bullet's aerodynamic characteristics, resulting in more pronounced changes and stronger correction capabilities. This research provides valuable insights into the aerodynamic characteristics of ballistic-correction bullets.
Experimental Studies on the Load Characteristics of Low-Speed Droplets Impinging onto Surface
Authors: Li Guandong , Qu Qiulin , Liu Peiqing
Published: June 2024

Droplet impingement on a wall is a fundamental scientific problem with wide engineering applications. When a droplet impacts the surface of an aircraft, it generates shock waves, airflow disturbances, and splashing phenomena. This not only has a negative impact on the aerodynamic performance and stability of the aircraft but also obstructs the field of view of optical sensors or causes distortion in optical devices. It can also damage the aircraft's structure, thus it’s vital to assess the droplet impact force for flight safety. However, droplets are often treated as rigid spheres for simplicity, but this does not reflect the real physical situation. In this paper, we utilized high-precision force sensors and high-speed imaging technology to experimentally investigate the impact dynamic of droplet impingement on a dry wall. The temporal evolution of force, the associated morphology changes and their relationship during collisions were analyzed systematically, we also elucidated the physical mechanisms underlying flow phenomenon. An unified and accurate mechanical model were established for droplet impingement, providing guidance for related engineering designs.
Load and Deformation Distribution Along the Bolt During Assembly Process
Authors: Li Zhixiang , Zhao Zhen , Zhang Jiaying
Published: June 2024

Bolt connection structure is widely utilized in modern large-scale equipment. Understanding the stress distribution along the bolt during assembly process is essential for improving its reliability. In this paper, assembly torque model is established to formulate the relationship between tightening torque and preload force, and a linear proportionality between them is obtained. The stress distribution during assembly process is modeled. Rotation angle and displacement distribution can be obtained from the proposed method. To validate our model, numerical simulation analysis is carried out to obtain the load and deformation distribution under different conditions. Comparison with the previous literature confirms the accuracy of the proposed model.
Stiffness and Strength Analysis of 2D Woven Composite Materials Based on Multi-scale Finite Element Method
Authors: Wang Weiye , Yan Renjun , Liu Kang , Qiu Yu
Published: June 2024

This study is based on the multi-scale finite element method and establishes RVE model of 2D woven fiber yarn and woven structure. The Stiffness matrix of plain, satin and twill 2D braided composites is calculated by applying Periodic boundary conditions and tensile shear loads in six directions. Write a UMAT subroutine to perform finite element simulation of the strength of woven RVE based on the three-dimensional Hashin failure criterion, and compare and verify it with existing experimental data. By comparing the load displacement curves of three types of braided composite materials under the same volume fraction, the stiffness and strength characteristics of the three types of braided composite materials, as well as the mechanical performance similarity issues caused by structural similarity, are studied.
Simulation Study of Shear Stress Distribution in Bolted Connection Structures of Sandwich Composite Plate
Authors: You Ruizhang , Yan Renjun , Zhu Haowen , Zhang Ziwei
Published: June 2024

For the shear problem of the bolt connection structure of Sandwich Composite Plate, shear test is carried out on two kinds of Bolt Connection Structure of Sandwich Composite Plate, namely, Pre-embedded countersunk bolt and Assembled countersunk bolt, and the shear strength and stress distribution of the two kinds of bolt connection structure are investigated by using ABAQUS, and the finite element simulation results coincided with the test phenomenon well. Using this model, the stress distribution under shear damage of the Bolt Connection Structure of Sandwich Composite Plate is analysed, and the influence of bolt preload is also analysed, and the results showed that: the stress of the Sandwich Composite Plate is mainly concentrated in the Skin on the bottom side, and gradually decreased to the top surface; the influence of bolt preload could be disregarded in the analysis of the shear strength and stress peak of the Sandwich Composite Plate.
Research and Practice on the Validation Testing Method of Safety of the Intended Functionality for High Way Assist Function
Authors: Guo Kuiyuan , Zhang Jiarui , Shi Juan , Zhang Zhiqiang , Ji Guotian
Published: June 2024

With the continuous development of the level of driving automation, the need for safety of the intended functionality (SOTIF) has gradually become prominent. As an important part of ensuring that vehicles meet the requirements of SOTIF, unknown scenario verification methods urgently need research and breakthroughs. A customized SOTIF verification test method for highway Assist (HWA) function based on Design Operation Domain (ODD) and a test route formulation method based on multi-dimensional key elements are studied and proposed. This method considers the data dimensions and environmental characteristics involved when deriving the acceptance criteria, and effectively meets the effective and practicable requirements of unknown scenario tests.
Improved Bidirectional Dynamic JPS Algorithm for Global Path Planning of Mobile Robot
Authors: Liu Ronghua , Wang Xin , Wu Di , Xie Chunyuan
Published: June 2024

This paper proposed to improve the bidirectional dynamic JPS algorithm in order to address the issues with the jump point search algorithm in the process of pathfinding, such as numerous path inflection points, numerous intermediate search hop points, numerous extended nodes, and lengthy pathfinding time in the process of finding jump points. The algorithm was based on the two-way dynamic hopping point search algorithm, defined the target points in the forward and reverse expansion directions dynamically, defined the heuristic function dynamically. In the process of searching each other from the starting point and the target point, the dynamic constraint ellipse was constructed to limit the expansion area of the jump point. The simulation results show that the optimized bidirectional dynamic JPS algorithm has a certain performance in general maps, especially in indoor environment maps with fewer obstacles and the target point is close to the starting point.
Accurate Finite Element Modeling of Bolted Joints and Modified IWAN Model
Authors: Li Jiuyi , Sun Yunhou , Yan Qiang , Kang Huaiqiang , Wang Haoxiang , Dong Shangwei
Published: June 2024

A three-dimensional finite element model of helical bolted joints is established in this paper, and the validity of the model establishment scheme is verified by a numerical examples of “the stress distribution on the bolted joint”. Then, Hysteresis curves of the resultant torque versus the applied torsion angle are obtained from the finite element analysis. The results indicate that: (1) The contact threads have experienced three states of adhesion, partial slip and macro slip during the tightening and loosening process; (2) In the state of macro sliding, the resultant torque exhibits an upward trend due to the increase of the clamping pressure in tightening process. On the contrary, the resultant torque exhibits a downward trend due to the decrease of the clamping pressure in the loosening process. A modified IWAN model is established for the three-dimensional helical bolted joint under torsional load by adding the residual stiffness and correction of torque based on the results of finite element analysis. The results of the modified IWAN model for the M12 bolted joint present that the modified IWAN model can reproduce the hysteresis curves obtained by finite element analysis accurately, and the modified IWAN model composed of three Jenkins elements can cover the dissipated energy precisely.
Research and Practice on Verification Test of Intended Functional Safety Awareness System Based on HWA System
Authors: Zhang Zhiqiang , Liu Shaohua , Shi Zhaoyuan , Shi Juan
Published: June 2024

With the development of driving automation technology, more and more vehicles are equipped with intelligent driving functions. The Ministry of Industry and Information Technology (MIIT) issued in 2021 “Intelligent connected Vehicle production Enterprises and Product Access Management Guide (Trial)” (draft for comment) proposed that “intelligent connected vehicle products should meet the process assurance requirements of functional safety, intended functional safety and cybersecurity.” As the “eyes” of the HWA functional system, the perception system, due to its complexity, may still have safety problems caused by functional limitations such as sensors or algorithms in the absence of faults. Therefore, the intended functional safety analysis and verification methods for the perception system are particularly important to ensure that the system does not have unreasonable safety risks. This paper describes the analysis method of the intended functional safety function deficiency, and puts forward the test verification strategy and test verification method of known hazard scenarios. Taking the HWA system as an example, this paper analyzes the hazard scenario of the HWA perception system based on camera and millimeter wave radar, conducts testing and verification evaluation for typical hazard scenarios, identifies the insufficient function of the HWA perception system, and puts forward functional modification suggestions to ensure that the perception system does not have unreasonable risks.
Simulation of Nanoindentation Technology Based on Rough Surface
Authors: Ye Zihao , Wang Yonghang , Yao Jiasheng , Jiang Jiankang
Published: June 2024

In order to study the influence of roughness on the nanoindentation test, finite element method was used to simulate the nanoindentation test process, and secondary indentation method was further proposed to suppress the influence of roughness on the indentation. After optimizing the indentation parameters, the relative error between the results of nanoindentation simulation for rough surface samples and smooth surface samples is stable within 5%. The secondary indentation method can effectively reduce the influence of roughness on nanoindentation test results.
A Study of the Effect of Frontal Crash Seat Belts on Driver Injury in a Certain Type of Wheeled Tactical Vehicle
Authors: Wang Tao , Zhou Yunbo , Zhang Ming
Published: June 2024

A finite element model of frontal collision of a certain type of wheeled tactical vehicle is established, and the collision test method is designed concerning the test requirements of Chinese frontal collision standard GB11551 and Chinese side collision standard GB2007 to get the acceleration inside the vehicle as well as the damage of the occupants, and the model accuracy is verified according to the results of the actual collision test and the simulation test, as well as the change of the energy in the process of the simulation. The Hybrid III 50% male dummy is placed in the driver’s seat, and under the action of different conditions and ways of restraint systems, the damage of each part of the dummy is obtained in the simulation test. The study shows that multi-point seat belts provide better occupant protection compared to traditional three-point seat belts in response to high-impact crash environments. It can improve the direction of the force on the occupant and effectively reduce the occupant injury. The final occupant WIC decreased by 25.9% relative to the initial four-point seat belt position, improving the survival rate of the occupants.
Monitoring potential impacts of climate change on the biodiversity of springs and springbrooks in the Central Alps
Authors: von Fumetti Stefanie , Aberhalden Angelika
Published: July 2024

Headwaters in alpine regions and their biodiversity are particularly threatened by climatic changes. Most predictions on their response to climate change are based on modeling approaches. Empirically gained data rarely exist for glacially influenced and groundwater-fed headwaters. In 2019, long-term monitoring was initiated at 15 springs, 8 springbrooks and 2 brooks in the UNESCO Biosphere Reserve Engiadina Val Müstair. The goal was to gain data on hydro-ecological aspects over several decades to understand whether (1) the environmental conditions change over time and (2) how these changes influence the composition of the species assemblages. Water temperature loggers were installed, pH, electrical conductivity, oxygen, nutrients and discharge were measured three times per year, and ecomorphological features were mapped two times per year. The meio- and macrofauna was sampled in 2019, 2020 and 2021 with a semi-quantitative approach. The results of the first 5 years of monitoring show that the physico-chemistry, water temperature and discharge confirm the stable character typical for groundwater-fed systems. Certain seasonal variability is evident, which possibly indicates an influence of permafrost or snow meltwater. The composition of the species assemblages differs significantly between sites but stays relatively constant over time within a site. Elevation and the availability of wood—parameters indicating forestation—significantly influence the species composition. This study provides a solid baseline on the environmental conditions and the fauna in springs and springbrooks in the Central Alps, which is needed for a proper interpretation of changes identified on a long-term basis.
DIVERGesTOOL – Entwicklung einer Toolbox zur Erfassung geschlechtlicher Vielfalt in der quantitativen Gesundheitsforschung
Authors: Horstmann Sophie , Schmechel Corinna , Becher Eva , Oertelt-Prigione Sabine , Palm Kerstin , Bolte Gabriele
Published: June 2024

In der epidemiologischen Gesundheitsforschung besteht ein großer Bedarf an umfassenden Erhebungsinstrumenten, die der Multidimensionalität und Variabilität von Geschlecht gerecht werden. Das Forschungsprojekt DIVERGesTOOL griff diesen in den letzten Jahren immer deutlicher werdenden Bedarf auf. Es verfolgte das Ziel, eine anwendungsorientierte Toolbox zur Erfassung geschlechtlicher Vielfalt für die quantitative Gesundheitsforschung in Deutschland zu entwickeln.

Der Entwicklungsprozess war partizipativ angelegt, Vertreter*innen großer epidemiologischer Studien in Deutschland wurden direkt einbezogen. Im Rahmen von vier gemeinsamen Workshops wurde eine Toolbox entwickelt, die sich aus mehreren Bestandteilen zusammensetzt: Die Basis-Items sind ein grundlegendes, allgemein nutzbares Set aus drei Fragen, die sich am Two-Step-Approach orientieren. Sie werden anstelle der bisher routinemäßig in den Gesundheitswissenschaften angewendeten binären Geschlechtsvariable empfohlen. Zudem enthält die Toolbox Zusatz-Items mit beispielhaften Fragebogen-Items für spezifische Fragestellungen oder Studienpopulationen. Ergänzt wurden die Items um ausführliche Anwendungshinweise und Hintergrundinformationen. Die Toolbox steht Interessierten online kostenlos über die Website des Projektes zur Verfügung (https://www.uni-bremen.de/divergestool-projekt/divergestool-toolbox).

Langfristig soll die DIVERGesTOOL-Toolbox Forschende dabei unterstützen, geschlechtliche Vielfalt in die eigene Forschung zu integrieren, und somit zu mehr Geschlechtersensibilität in der Gesundheitsforschung und validen Forschungsergebnissen beitragen.
Involvement of dysregulated hippocampal histone H3K9 methylation at the promoter of the BDNF gene in impaired memory extinction
Authors: Oga Kenichi , Fuchikami Manabu , Kobayashi Hironori , Miyagi Tatsuhiro , Fujita Sho , Fujita Satoshi , Okada Satoshi , Morinobu Shigeru
Published: June 2024

Rationale

Since the precise mechanisms of posttraumatic stress disorder (PTSD) remain unknown, effective treatment interventions have not yet been established. Impaired extinction of fear memory (EFM) is one of the core symptoms of PTSD and is associated with stress-induced epigenetic change in gene expression.

Objectives

In this study, we examined whether the involvement of histone H3 lysine 9 dimethylation (H3K9me2) in EFM is mediated through brain-derived neurotrophic factor (BDNF) expression in the hippocampus, and whether BIX01294, a selective G9a and GLP histone methyltransferase inhibitor, could be treatment for impaired EFM in an animal model of PTSD.

Methods

The single prolonged stress (SPS) paradigm was used to model PTSD. We measured BDNF mRNA levels by RT-PCR, and H3K9me2 levels in the BDNF gene promoters by chromatin immunoprecipitation-qPCR. After undergoing contextual fear conditioning and hippocampal injection of BIX01294, male rats were subjected to extinction training and extinction testing and their freezing times and BDNF mRNA levels were measured.

Results

Compared to sham rats, SPS rats showed decreased BDNF mRNA levels 2 h after extinction training, no significant changes in levels of global H3K9me2 prior to extinction training, and increased levels of H3K9me2 in BDNF gene promoter IV, but not in BDNF gene promoter I. Administration of BIX01294 ameliorated the decrease in BDNF mRNA levels 2 h after extinction training and subsequently alleviated impaired EFM in extinction tests in SPS rats.

Conclusion

We conclude that reduced hippocampal levels of BDNF mRNA due to increase in H3K9me2 levels may play a role in PTSD-associated EFM impairment, and BIX01294 could be a PTSD treatment option.
Microplastics Biodegradation by Estuarine and Landfill Microbiomes
Authors: Pires Cristina S. , Costa Luís , Barbosa Sónia G. , Sequeira João Carlos , Cachetas Diogo , Freitas José P. , Martins Gilberto , Machado Ana Vera , Cavaleiro Ana J. , Salvador Andreia F.
Published: June 2024

Plastic pollution poses a worldwide environmental challenge, affecting wildlife and human health. Assessing the biodegradation capabilities of natural microbiomes in environments contaminated with microplastics is crucial for mitigating the effects of plastic pollution. In this work, we evaluated the potential of landfill leachate (LL) and estuarine sediments (ES) to biodegrade polyethylene (PE), polyethylene terephthalate (PET), and polycaprolactone (PCL), under aerobic, anaerobic, thermophilic, and mesophilic conditions. PCL underwent extensive aerobic biodegradation with LL (99 ± 7%) and ES (78 ± 3%) within 50–60 days. Under anaerobic conditions, LL degraded 87 ± 19% of PCL in 60 days, whereas ES showed minimal biodegradation (3 ± 0.3%). PE and PET showed no notable degradation. Metataxonomics results (16S rRNA sequencing) revealed the presence of highly abundant thermophilic microorganisms assigned to Coprothermobacter sp. (6.8% and 28% relative abundance in anaerobic and aerobic incubations, respectively). Coprothermobacter spp. contain genes encoding two enzymes, an esterase and a thermostable monoacylglycerol lipase, that can potentially catalyze PCL hydrolysis. These results suggest that Coprothermobacter sp. may be pivotal in landfill leachate microbiomes for thermophilic PCL biodegradation across varying conditions. The anaerobic microbial community was dominated by hydrogenotrophic methanogens assigned to Methanothermobacter sp. (21%), pointing at possible syntrophic interactions with Coprothermobacter sp. (a H2-producer) during PCL biodegradation. In the aerobic experiments, fungi dominated the eukaryotic microbial community (e.g., Exophiala (41%), Penicillium (17%), and Mucor (18%)), suggesting that aerobic PCL biodegradation by LL involves collaboration between fungi and bacteria. Our findings bring insights on the microbial communities and microbial interactions mediating plastic biodegradation, offering valuable perspectives for plastic pollution mitigation.
Membrane protein Bcsdr2 mediates biofilm integrity, hyphal growth and virulence of Botrytis cinerea
Authors: Zhang Wei , Cao Yi , Li Hua , Rasmey Abdel-Hamied M. , Zhang Kecheng , Shi Liming , Ge Beibei
Published: June 2024

Grey mould caused by Botrytis cinerea is a devastating disease responsible for large losses to agricultural production, and B. cinerea is a necrotrophic model fungal plant pathogen. Membrane proteins are important targets of fungicides and hotspots in the research and development of fungicide products. Wuyiencin affects the permeability and pathogenicity of B. cinerea, parallel reaction monitoring revealed the association of membrane protein Bcsdr2, and the bacteriostatic mechanism of wuyiencin was elucidated. In the present work, we generated and characterised ΔBcsdr2 deletion and complemented mutant B. cinerea strains. The ΔBcsdr2 deletion mutants exhibited biofilm loss and dissolution, and their functional activity was illustrated by reduced necrotic colonisation on strawberry and grape fruits. Targeted deletion of Bcsdr2 also blocked several phenotypic defects in aspects of mycelial growth, conidiation and virulence. All phenotypic defects were restored by targeted gene complementation. The roles of Bcsdr2 in biofilms and pathogenicity were also supported by quantitative real-time RT-PCR results showing that phosphatidylserine decarboxylase synthesis gene Bcpsd and chitin synthase gene BcCHSVII were downregulated in the early stages of infection for the ΔBcsdr2 strain. The results suggest that Bcsdr2 plays important roles in regulating various cellular processes in B. cinerea.

Key points

• The mechanism of wuyiencin inhibits B. cinerea is closely associated with membrane proteins.

• Wuyiencin can downregulate the expression of the membrane protein Bcsdr2 in B. cinerea.

• Bcsdr2 is involved in regulating B. cinerea virulence, growth and development.
Treatment of chronic and complex meniscal tears with arthroscopic meniscus repair augmented with collagen matrix wrapping: failure rate and functional outcomes
Authors: Vicens Marga H. , Pujol Oriol , Portas-Torres Irene , Aguilar Marc , Joshi Nayana , Minguell Joan , Castellet Enric , Casaccia Marcelo
Published: June 2024

Purpose

Meniscal wrapping is a fully arthroscopic technique that involves enhanced meniscal repair with a tissue-engineered collagen matrix wrapping. This study aims to investigate the feasibility of using the meniscal wrapping technique for the treatment of chronic or complex meniscal tears. The primary objective is to assess its failure rate. The secondary objectives are to analyse complication rate, functional outcomes and overall patient satisfaction.

Methods

This retrospective case series study included patients who sustained chronic and complex tears undergoing meniscal wrapping with autologous liquid bone marrow injection. Failure rate was considered if the patient underwent partial or complete meniscectomy or knee replacement during the follow-up, while other unexpected knee reoperations were considered as complications. Clinical outcomes were evaluated through the IKDC score, Tegner Activity Score and Short Assessment of Patient Satisfaction.

Results

Twenty-one patients were included (15 non-acute bucket-handle tears, three non-acute horizontal tears and three non-acute complex injuries). The failure rate was 9.5% at 33 months. The rate of other unplanned reoperations was 14.3%, but none of these complications were apparently directly related to the wrapping technique. The average postoperative IKDC was 73.3/100. No statistically significant difference was encountered between preinjury and postoperative Tegner Activity Score. The mean overall patient satisfaction was 88.3/100.

Conclusions

Meniscal wrapping can be safely used as an adjunctive technique to meniscal repair in such difficult-to-treat cases to preserve the meniscus. The technique achieves a low failure rate and promising results of knee function, and patient satisfaction.
Individual flexibility in group foraging behaviour of reef manta rays (Mobula alfredi)
Authors: Murray Annie , Royauté Raphaël , Stevens Guy M. W. , Roberts Callum , Arnold Kathryn E.
Published: July 2024

Flexibility in animal foraging strategies can increase overall feeding efficiency for individuals. For example, group foraging can increase the efficiency of resource exploitation; conversely solo foraging can reduce intraspecific competition, particularly at low resource densities. The cost–benefit trade-off of such flexibility is likely to differ within and among individuals. Reef manta rays (Mobula alfredi) are large filter-feeding elasmobranchs that often aggregate to feed on ephemeral upwellings of zooplankton. Over three years in the Maldives, we free-dived to film 3106 foraging events involving 343 individually identifiable M. alfredi. Individuals fed either solo or in groups with a clear leader plus between one and eight followers. M. alfredi were significantly more likely to forage in groups than solo at high just prior to high tide and when aggregations were larger. Within aggregations, individuals foraged in larger groups when more food was available, and when the overall aggregations were relatively large suggesting that foraging in large groups was more beneficial when food is abundant, and the costs of intraspecific competition were outweighed by the efficiency resulting from group foraging strategies. Females, the larger sex, were more likely to lead foraging groups than males. The high within-individual variance (over 70%), suggested individuals were unpredictable across all foraging behaviours, thus individual M. alfredi cannot be classified into foraging types or specialists. Instead, each individual was capable of considerable behavioural flexibility, as predicted for a species reliant on spatially and temporally ephemeral resources.

Significance statement

Reef manta rays (Mobula alfredi), listed as “Vulnerable” on the IUCN Red List, are at risk from targeted and by-catch fisheries due to their slow life history and aggregative behaviour. M. alfredi feed together in aggregations on short-lived glut of microscopic zooplankton. Over three years in the Maldives, we filmed 3106 foraging events involving 343 individually identifiable M. alfredi. Manta rays were more likely to forage in groups than solo just prior to high tide and when aggregations were larger, attracted by the influx of zooplankton. Foraging groups included more individuals when plankton was more abundant. However, individuals flipped between solo and group foraging and did not specialise. Foraging groups were most often led by females, the larger sex. Individuals were very flexible in how they foraged, which makes sense for a species that relies on a food source that varies enormously in when, where and for how long it is available. Understanding manta ray foraging behaviour will help conservation management efforts and predict their responses to climate change.
A three-dimensional extension of the slope chain code: analyzing the tortuosity of the flagellar beat of human sperm
Authors: Bribiesca-Sánchez Andrés , Guzmán Adolfo , Montoya Fernando , Díaz-Guerrero Dan S. , Hernández Haydeé O. , Hernández-Herrera Paul , Darszon Alberto , Corkidi Gabriel , Bribiesca Ernesto
Published: June 2024

In the realm of 3D image processing, accurately representing the geometric nuances of line curves is crucial. Building upon the foundation set by the slope chain code, which adeptly represents intricate two-dimensional curves using an array capturing the exterior angles at each vertex, this study introduces an innovative 3D encoding method tailored for polygonal curves. This 3D encoding employs parallel slope and torsion chains, ensuring invariance to common transformations like translations, rotations, and uniform scaling, while also demonstrating robustness against mirror imaging and variable starting points. A hallmark feature of this method is its ability to compute tortuosity, a descriptor of curve complexity or winding nature. By applying this technique to biomedical engineering, we delved into the flagellar beat patterns of human sperm. These insights underscore the versatility of our 3D encoding across diverse computer vision applications.
A second life for mining waste as an amendment for soil remediation
Authors: Salgado Lorena , Aparicio Laura , Afif Elías , Fernández-López Esther , Gallego Jose R. , Forján Rubén
Published: June 2024

Mining is a cornerstone of the productive system, particularly in sectors, such as renewable energy and electronic equipment production, where its significance is anticipated to grow in the coming years. Aligned with the principles of Nature-Based Solutions and Zero Waste policies, recycling mining waste as soil amendments could concurrently restore degraded areas and reduce the disposal of mining waste. In this context, we aimed to remediate a post-mining soil primarily impacted by heavy metal pollution using an alkaline waste generated in dunite exploitation, either in combination with compost or independently in field conditions. The objectives were to minimize heavy metal(loid)s mobility (As, Cu, Cd, Ni, Pb, and Se), to improve soil health, and stimulate plant growth (phytoremediation, Lolium perenne L. was used). Results revealed that the combination of dunite and compost successfully reduced the concentrations of available Cu and Ni in the soil by more than four times, significantly enhanced soil properties, and promoted the harvest of a greater biomass. Additionally, Lolium perenne L. demonstrated phytostabilizing capacity for Cu and Ni in the soil treated with the amendments. In conclusion, the utilization of combined dunite-based and organic amendments proves to be a favorable strategy for restoring polluted post-mining soils.