Search Results (297)

This study examines the applicability of Plasma Transferred Arc (PTA) surface treatment as an advanced technique for the refurbishment of railway wheel treads. Conventional wheel reprofiling, typically performed on semi-automatic lathes, requires the removal of a minimum of 6 mm of material from the running surface, which accelerates rim thinning and ultimately necessitates wheel replacement. Moreover, the reprofiled surfaces are not subjected to any subsequent treatment aimed at enhancing their durability. To overcome these limitations, PTA cladding was selected due to its ability to generate surface layers with superior mechanical and tribological properties. In contrast to widely used diode laser technologies, PTA enables the deposition of alloying materials in powder form, ensuring a stable, controllable, and efficient cladding process. The resulting microstructure consists of a heat-affected zone, a transition zone, and a re-melted zone, each exhibiting significantly increased hardness relative to the untreated base material. The process facilitates the incorporation of metallic particles into the surface layer, promoting the formation of a dense, wear-resistant coating. These materials possess huge potential utility regarding the wear resistance reaching even ca 10% of the base material wear in the case of 505 PTA and over 20% in the case of the 15 E material. The findings indicate that PTA surface treatment has substantial potential to extend the operational lifespan of railway wheels by providing a highly durable and mechanically robust surface, thereby reducing maintenance frequency and the associated costs. Full article

This study evaluates an Adaptive Monte Carlo Localization-Extended Kalman Filter (AMCL-EKF) pose-estimation stack for repeatable 2D LiDAR SLAM in GPS-denied indoor inspection scenarios. AMCL was used as an online map-referenced correction source fused with LiDAR odometry and Inertial Measurement Unit (IMU) data, and the resulting pose estimate was supplied online to three SLAM backends: Cartographer, GMapping, and SLAM Toolbox. Experiments were performed with a wheeled Husarion Panther and a quadruped Boston Dynamics Spot in three indoor environments of different geometric complexity, producing 720 SLAM executions. Trajectory repeatability was assessed using SE(2)-aligned pairwise and centroid-based ATE-style dispersion and translational RPE, while map repeatability was evaluated with occupied-cell IoU. Accordingly, the metrics were used to quantify between-run dispersion rather than absolute accuracy against external ground-truth data. The results show that AMCL-EKF fusion is highly dependent on the environment, platform, and SLAM backend. AMCL improved selected configurations, especially for Spot in structured environments and for Panther map consistency, but degraded others in geometrically repetitive corridors and mixed-structure spaces. The study also shows that the presence of AMCL-assisted odometry correction alone does not determine final trajectory repeatability, because each SLAM backend incorporates the supplied fused pose estimate differently. The findings support confidence-aware AMCL integration and motivate integrated SLAM architectures resistant to over-correction. These results provide guidance for robust autonomous mapping and inspection with heterogeneous mobile robotic platforms in real environments. Full article

Background: In rodent models of intracranial tumor development, evaluating the actual burden experienced by animals beyond procedural severity is essential for ethical and legal compliance. This study examined whether voluntary wheel running (VWR) could serve as a sensitive indicator of post-surgical burden following subcutaneous transmitter implantation, tumor cell injection, and tumor resection. It also assessed whether VWR supports the detection of humane endpoints. VWR outcomes were compared with body weight, clinical scores, heart rate, and activity levels recorded via telemetry. Methods: Fourteen male BDIX rats were housed individually in cages equipped with a running wheel. Under general anesthesia, telemetric devices to monitor heart rate and activity were subcutaneously implanted. After recovery, glioblastoma BT4Ca cells were stereotaxically injected into the right frontal cortex. Eight days later, the resulting tumors were microsurgically resected. Body weight, VWR, heart rate, and general activity were continuously monitored until the animals reached humane endpoint criteria, indicated by sudden weight loss and clinical deterioration. Results: On average, body weight and VWR declined significantly after all surgical procedures, with tumor resection causing the most pronounced effect. As animals approached the endpoint, a marked drop in these parameters was observed, along with an increased clinical score (p < 0.05). Activity measures supported these findings, though less consistently than weight and VWR. Conclusions: Monitoring body weight and VWR enables an effective assessment of the actual postoperative burden experienced by rats undergoing surgeries of different procedural complexity. Moreover, VWR is a valuable supplementary tool for identifying humane endpoints alongside body weight and clinical scoring. Full article

The increase in antioxidant defenses mediated by physical exercise signaling is proposed to be a protective factor against brain aging and neurodegeneration. However, the processes involved, particularly the response of senescence markers and cell fitness status in the context of Alzheimer’s disease (AD) pathology, remain unclear. We analyzed male and female 5XFAD transgenic AD mice subjected to 6 months of voluntary wheel running using molecular and behavioral techniques. Levels of mRNA of selected genes, mitochondrial complex proteins, and proteasomal function, were analyzed in the cerebral cortex or hippocampus. In an exploratory translational approach, proteasomal dynamics- and senescence-related genes were analyzed in peripheral blood from middle-aged amateur sportsmen. Physical exercise increased expression of antioxidant genes and modulated epigenetic genes in 5XFAD male and female mice. An increase in protein levels of hippocampal mitochondrial complexes CIII and CV was also induced in males. Both exercised 5XFAD mice and veteran sportsmen showed improved proteasomal status and decreased expression of senescence genes. Exercised mice showed memory and behavior preservation, as well as increases in brain metabolic fitness and gene modulation. These changes may contribute to the neuroprotective effect of physical exercise. Full article

The wheel–rail impact effect is prominent in the low vibration track (LVT) in the curved sections of heavy-haul railways, where fastener failure and the support block hanging void are prone to occurring. To investigate the impact of these issues on the dynamic characteristics of the vehicle–track coupled system, this study establishes a coupled dynamics model of a heavy-haul train and LVT, taking into account the topological relationships of vehicle components, multipoint wheel–rail contact, and track irregularities. Comparative analyses are conducted to evaluate the effects of the location, quantity, and failure degree of fastener failure and support block hanging voids on running safety and stability. The results show that (1) compared to the normal condition, fastener failure and support block hanging voids lead to varying degrees of increases in response indicators, thereby intensifying the wheel–rail impact; (2) bilateral failure exhibits more pronounced dynamic responses than unilateral failure, and when the number of failed fasteners or hanging voids exceeds one, the maximum wheel load reduction rate increases significantly; (3) as the gap of the hanging void increases, the dynamic response also increases, and when the gap reaches approximately 3 mm, the support block can be considered fully suspended; and (4) comprehensive analysis indicates that fastener failure poses a greater threat to running safety than support block hanging voids and thus warrants greater attention in practical engineering applications. This study provides theoretical support for the maintenance and repair of heavy-haul railways. Full article

Muscle wasting contributes substantially to inflammatory bowel disease (IBD)-related disability, but its association with colitis severity across disease stages remains poorly characterized. We therefore assessed skeletal muscle mass, fiber morphology, and voluntary wheel-running performance in Winnie mice—a spontaneous Muc2 mutant model of chronic colitis—in separate female and male homozygous mutant and WT littermate cohorts. Assessments were performed at 5 weeks, before overt colitis, and at 15 weeks, in a cohort with more pronounced colitis. Outcomes included disease activity index (DAI), fecal lipocalin-2 (LCN-2), wheel-running metrics, soleus and tibialis anterior mass, and minimal Feret’s diameter distributions. At 5 weeks, Winnie mice showed no overt disease activity and no consistent structural muscle deficit. In contrast, the 15-week cohort exhibited marked colitis in both sexes, with increased DAI and LCN-2, reduced voluntary wheel-running performance, lower soleus and tibialis anterior mass, and smaller muscle fiber diameters with left-shifted size distributions. Correlation analyses identified associations between fecal LCN-2, skeletal muscle mass and size, and wheel-running distance and velocity, supporting a link between intestinal inflammation and muscle impairment in this model. These cross-sectional data are consistent with reduced voluntary activity and structural myopathy during progression of spontaneous colitis. The Winnie mouse model therefore provides a clinically relevant preclinical platform to study IBD-associated muscle wasting and its association with intestinal inflammation. Full article

This paper proposes the Branch-Priority Exploration (BPE) framework for autonomous coverage in confined industrial corridor environments. BPE integrates three components: (1) a symmetry-aware LiDAR branch detector; (2) a hierarchical BFS/DFS mode-switching policy; and (3) a barrier-based branch memory. Frontier-based methods often struggle in industrial corridors where branches split off from the main corridor. The symmetric layout of such environments, featuring T-shaped junctions and L-shaped turns, creates recurring geometric patterns that conventional frontier scoring fails to exploit. When the robot reaches a junction, nearby frontier candidates often receive similar scores, causing repeated target switching as the local map changes. Meanwhile, frontier cells inside a branch tend to score lower than those along the main corridor; so, the robot often bypasses the branch and continues forward, which leads to additional backtracking later. Even when the robot eventually returns, residual frontier cells near the entrance may attract the planner repeatedly, causing redundant re-entry into already-covered branches. To address these issues, a branch-priority exploration framework is developed. A symmetry-aware branch detection module uses LiDAR range measurements from multiple directions to identify T-shaped junctions and lateral openings, applying identical geometric criteria to lateral openings on either side of the robot. This allows branch entry to be triggered by explicit geometric evidence, rather than frontier score comparisons that tend to be unreliable near intersections. When a branch is detected, the robot transitions from BFS mode to DFS mode for systematic branch coverage. Entry and post-return locks prevent mode reversal before the robot commits to the new heading. Once a branch is completed, a permanent virtual barrier is placed at its entrance; so, the planner no longer routes the robot back into that branch. The framework is formalized as a constrained coverage problem on occupancy grids, and monotonic coverage progress and finite branch completion under barrier memory are established theoretically. A fully reproducible ROS implementation on a wheeled platform with differential drive is validated. Experiments span several corridor environments of increasing topological complexity. Compared to a nearest-frontier baseline, the proposed method substantially reduces both exploration time and goal cancellations while achieving complete coverage across all trials. The cancellation count matches the number of T-branches per environment, with near-zero variance across repeated runs. Full article

According to investigation, the wheelset generally appears in a mass eccentric condition. Therefore, the finite element model of a wheelset–track system with mass eccentricity was established in this study to investigate the dynamic response characteristics based on the frictional self-excited vibration theory. The research results show that, when the frictional self-excited vibration of the wheelset–track system occurs, the unstable vibration characteristics of the wheelset–track system corresponding to different dynamic imbalance values are almost the same. That is, the magnitude of the dynamic imbalance value has little influence on the frictional self-excited vibration of the wheelset–track system. Simultaneously, from the perspective of the excitation frequency f of the wheel polygonal wear, it shows a trend of increasing frequency with an increase in the running speed. Ultimately, as the phase difference in mass eccentricity grows, pronounced instability becomes evident within the mid- to high-frequency ranges once friction-induced self-excitation arises in the wheelset–track system. This condition readily promotes high-order polygonal wear on the wheel surfaces. Full article

Low physical activity is a common risk factor for hypertension and dementia. We investigated whether voluntary running wheel activity (VRWA) ameliorates the effects of hypertension in the brain. Forty-six six-week-old female spontaneously hypertensive rats were randomly selected in a sedentary control group (SHR-S; n = 21) or had access to running wheels during their active nighttime (SHR-R; n = 15). Age-matched normotensive Wistar rats served as controls (WIS; n = 10). Animals were sacrificed after six months. The cortex, medulla oblongata, and olfactory bulb were prepared. Oxidative stress was analyzed by DHE staining, protein expression by Western blots, mRNA expression by qRT-PCR and blood pressure by a tail-cuff method. VRWA reduced heart rates but not blood pressure. All SHRs displayed a strong reduction of Ucp2 brain expression in a blood-pressure-dependent way. VRWA did not improve the expression of Ucp2 but increased the expression of Cat and reduced oxidative stress in the cortex. Hypertension increased the expression of Ren in the medulla oblongata without any effect of VRWA on this parameter. VRWA generally affected mRNA expression stronger in the cortex than in the other parts of the brain. In conclusion, high physical activity ameliorated oxidative stress in the cortex in a blood-pressure-independent way. Full article

Wheeled bipedal robots are promising for industrial mobility because they combine tight turning, agile balancing, and efficient rolling. Their inherently unstable and underactuated dynamics make reliable reference tracking challenging, particularly in the presence of sustained external disturbances and modeling errors. This paper presents a systematic modeling and control study using a three-degrees-of-freedom sagittal plane representation derived from the original six-degrees-of-freedom dynamics. Two linear tracking controllers are designed and compared: a full state feedback tracking controller and a linear quadratic servo controller with integral action. Practical performance is validated through real-time hardware in the loop simulation, where the controller runs on embedded hardware and the plant is executed on a real-time target including discrete time-sampling effects and analog input output communication noise associated with signal transmission. The results show that both controllers achieve stabilization, while the comparative HILS results reveal a trade-off rather than a uniformly superior controller. The full state feedback controller often yields lower finite-horizon position tracking errors, whereas the linear quadratic servo controller provides tighter body-pitch regulation and the more reliable removal of steady-state offset under sustained constant disturbances. These results demonstrate the feasibility of optimal servo control on cost-effective embedded platforms and indicate that controller selection should depend on the desired balance, considering tracking accuracy, disturbance rejection, convergence behavior, and actuator usage. Full article

With the conclusion of proton–proton collision data-taking in 2025, the ATLAS experiment has now integrated a luminosity exceeding 300 ${\mathrm{fb}}^{-1}$ during the Run 3 period, which began in July 2022 following Long Shutdown 2 (LS2). During LS2, a series of detector upgrades were implemented, including the installation of the New Small Wheel (NSW) in the innermost stations of the Muon Spectrometer end-caps. The ATLAS Muon Spectrometer, the largest muon system ever built at a collider, now comprises both established gaseous detectors—Monitored Drift Tubes, Thin Gap Chambers, and Resistive Plate Chambers—and newer detectors like Micromegas and small-strip TGCs in the NSW. These new systems are now in stable operation following an extensive phase of construction and commissioning, providing enhanced muon tracking and trigger capabilities. This presentation covers the performance of the muon system, focusing on the stability of the established detectors over time, their ability to handle increasing luminosity and associated irradiation levels, and studies on detector aging. Emphasis will be placed on the NSW upgrade, including the strategies adopted for alignment, track reconstruction, and trigger. The performance results presented in this contribution are based on Run 3 data collected up to 2024. Full article

In skeletal muscles fibers, cellular respiration, excitation–contraction (EC) coupling (the mechanism that translates action potentials in Ca²⁺ release), and store-operated Ca²⁺ entry (SOCE, a mechanism that allows recovery of external Ca²⁺ during fatigue) take place in organelles specifically dedicated to each function: (a) aerobic ATP production in mitochondria; (b) EC coupling in intracellular junctions formed by association between transverse tubules (TTs) and sarcoplasmic reticulum (SR) named triads; (c) SOCE in Ca²⁺ entry units (CEUs), SR-TT junctions that are in continuity with membranes of triads, but that contain a different molecular machinery (see Graphical Abstract). In the past 20 years, we have studied skeletal muscle fibers by collecting biopsies from humans and isolating muscles from animal models (mouse, rat, rabbit) under different conditions of muscle inactivity (sedentary aging, denervation, immobilization by casting) and after exercise, either after voluntary training in humans (running, biking, etc.) or in mice kept in wheel cages or after running protocols on a treadmill. In all these studies, we have assessed the ultrastructure of the mitochondrial network and of the sarcotubular system (i.e., SR plus TTs) by electron microscopy (EM) and then collected functional data correlating (i) the changes occurring with aging and inactivity with a loss-of-function, and (ii) the structural improvement/rescue after exercise with a gain-of-function. The picture that emerged from this long journey points to the importance of the internal architecture of muscle fibers for their capability to function properly. Indeed, we discovered how the intracellular organization of the mitochondrial network and of the membrane systems involved in controlling intracellular calcium concentration (i[Ca²⁺]) is finely controlled and remodeled by inactivity and exercise. In this manuscript, we give an integrated picture of changes caused by inactivity and exercise and how they may affect muscle function. Full article

Background: Estrogen deficiency following human menopause or rodent ovariectomy (OVX) induces adverse alterations in body composition and metabolic function. This study investigated the combined effects of acetic acid supplementation and voluntary exercise on metabolic health and skeletal muscle mitochondrial function using an OVX mouse model. Methods: Forty female C57BL/6J mice (8 weeks old) were randomly assigned to 5 groups: sham (SHM), ovariectomized control (OVX), OVX with exercise (OVX-E), OVX with acetic acid (OVX-A), and OVX with both interventions (OVX-AE). Following a 1-week recovery from OVX, a 13-week intervention was initiated: 5% sodium acetate-supplemented chow and/or voluntary wheel running. Body composition, glucose tolerance, total energy expenditure, skeletal muscle mitochondrial function, and the contents of AMPKα, PGC-1α, and carbonyl protein were assessed. Results: OVX impaired whole-body metabolism and skeletal muscle mitochondrial function, specifically in the gastrocnemius muscle. While the exercise alone failed to mitigate the OVX-induced mitochondrial dysfunction, the combined treatment of exercise and acetic acid supplementation significantly rescued from the OVX-induced mitochondrial dysfunction. Conclusions: OVX resulted in detrimental changes in whole-body metabolism, but voluntary exercise and/or acetic acid supplementation had no rescuing effects on those parameters. In gastrocnemius muscle, acetic acid supplementation during exercise enhanced mitochondrial function in OVX mice. Full article

Cimicifuga racemosa extracts, particularly the ethanolic extract Ze 450, are widely used to alleviate menopausal symptoms, such as hot flushes and excessive sweating. While their clinical efficacy is well established, the effects of these interventions on systemic energy metabolism remain unclear. This pilot study investigated the impact of Ze 450 on body composition, metabolic markers, and voluntary physical activity in non-ovariectomized female Wistar rats. Animals (N = 36) received Ze 450 at either 30 mg/kg or 130 mg/kg body weight, with or without access to voluntary wheel running over four weeks. Neither treatment influenced body weight gain or final body weight, indicating normal growth across all groups. Post-mortem analyses included visceral fat mass, serum cholesterol, and leptin levels. Both Ze 450 and running reduced visceral fat mass, adipocyte size, and circulating leptin levels, suggesting that they share overlapping mechanisms. Serum cholesterol was significantly lowered by running but remained unaffected by Ze 450, while liver weight and alanine aminotransferase activity were unchanged, confirming hepatic safety. Collectively, Ze 450 improved key metabolic parameters related to adiposity and appetite without affecting hepatic integrity, highlighting its potential as a safe, non-hormonal metabolic modulator complementary to physical activity. Full article

In recent years, while progress has been made in barrier-free design, the complete elimination of physical barriers such as uneven road surfaces and stairs remains difficult, and wheelchair passengers continue to face significant mobility constraints. This study aims to verify the effectiveness of a transformable quadruped wheelchair that can switch between two modes of movement: walking and wheeled travel. Specifically, reinforcement learning using Proximal Policy Optimization (PPO) was used to acquire walking strategies for uneven terrain and wheeled travel strategies for flat terrain. NVIDIA Isaac Sim was used for simulation. To evaluate the stability of both modes, we performed a frequency analysis of the passenger’s acceleration data. As a result, we observed periodic vibrations around 2 Hz in the vertical direction in walking mode, while in wheeled mode, we confirmed extremely small vibrations and stable running. Furthermore, we distilled these two strategies into a single mode-conditional strategy and conducted long-distance running experiments involving mode transformation. The results demonstrated that by adaptively switching between walking and wheeled modes depending on the terrain, mobility efficiency was significantly improved compared to continuous operation in a single mode. This study demonstrates the effectiveness of an approach that involves learning multiple specialized strategies and switching between them as needed to efficiently traverse diverse environments using a transformable robot. Full article