Search Results (4,617)

Modern Chinese traditional-style buildings (MCTBs) preserve the beam–column –construction of historical architecture, but the irregularity of joints continues to constrain their seismic performance. To enhance the energy-dissipation capacity of these joints, viscous dampers were installed at the Que-Ti braces (cantilever corbels beneath beam ends) of beam–column joints. Six 1/2.6-scale specimens were designed and tested under periodic dynamic loading. The experimental results indicate that the installation of viscous dampers significantly improved the failure modes by delaying the formation of plastic hinges at beam ends, as well as the initiation of base material cracking and weld fracture. After damper installation, the joint strength increased by 18–46%, and the improvement was more pronounced in double beam–column joints. A finite element model was established in ABAQUS to investigate the effects of axial load ratio, damping coefficient and damper length on joint strength, hysteretic energy dissipation, and damper mechanical response. The results revealed that the axial load ratio has a limited influence on the overall joint strength and damper contribution. Increasing the damping coefficient significantly enhances the joint hysteretic energy dissipation and peak damper force, exhibiting an approximately linear relationship. The damper length has a minor influence on joint strength, but a longer damper slightly increases the hysteretic energy dissipation and equivalent viscous damping, while the maximum damper displacement is mainly governed by the damper length. Similar damper contributions are observed in single beam–column and double beam–column joints, indicating stable and reliable energy-dissipation behavior. The proposed numerical approach can predict the axial deformation, velocity, and force demands of dampers under various loading conditions. In addition, preliminary design recommendations for irregular steel joints with supplemental viscous dampers in MCTBs were developed based on ancient Chinese architectural literature and refined through combined experimental observations and finite element analyses (FEA). Full article

Background: Hypermobile Ehlers–Danlos syndrome (hEDS), the most common EDS subtype, is characterized by chronic pain and joint laxity, yet no definitive causative genes or imaging-based diagnostic criteria have been established. This study investigated the genetic basis of hEDS using whole-exome sequencing (WES) and objectively evaluated ankle instability. Methods: We conducted an observational cohort study with a case–control comparison, including 22 patients and a three-generation Korean family (six individuals, four affected) diagnosed with hEDS by the 2017 criteria. WES was performed; ankle laxity was assessed by the anterior drawer test (ADT), stress ultrasonography, and stress radiography. Healthy young adults (n = 24, Beighton score < 5) from our previous study served as controls. Results: The hEDS cohort had a mean Beighton score of 8.5, with all participants reporting a family history of hypermobility and musculoskeletal complications. Family-based WES identified variants in CD44 (c.1516 + 1G > A), ITIH2 (c.783C > G), and ADAM21 (c.397C > T) in all affected individuals. In 22 unrelated patients, 114 variants in 103 candidate genes were identified; 17 patients harbored variants in genes from the same pathways as the family-derived causative genes. Compared with controls, the hEDS group showed significantly greater manual ADT grade, anterior talofibular ligament (ATFL) length at rest and under stress, dynamic ATFL change, anterior talar translation, and talar tilt. Conclusions: These findings provide molecular evidence that hEDS is a multifactorial disorder involving interconnected biological pathways, and confirm ankle instability as a clinically meaningful diagnostic feature. These complementary approaches may improve diagnostic accuracy and provide insights into the prognosis and therapeutic strategies for hEDS. Full article

This article discusses rheumatoid arthritis (RA) as a chronic, systemic autoimmune disease leading to progressive joint damage and multi-organ complications. The complex pathogenesis of the disease is presented, involving the interaction of environmental, genetic, and immunological factors, including the role of autoantibodies and proinflammatory cytokines. Particular attention is paid to leflunomide, a disease-modifying antirheumatic drug (DMARD), which primarily works by inhibiting the DHODH enzyme, leading to reduced T and B cell proliferation. The additional anti-inflammatory properties of the drug’s active metabolite, teriflunomide, and its impact on signaling pathways related to the immune response are also discussed. This article examines the variability in patient responses to leflunomide treatment in terms of both efficacy and toxicity, with particular emphasis on the potential role of pharmacogenetic factors. It was pointed out that polymorphisms in genes related to drug metabolism, transport, and mechanism of action may influence the pharmacokinetics and safety of the therapy. It was also emphasized that the available data are primarily derived from observational studies and small cohorts, and the results are often inconsistent. Although some genetic variants and plasma teriflunomide concentrations show potential as predictors of treatment response, the current level of evidence does not support the routine use of pharmacogenetic testing in clinical practice. The article emphasizes that the pharmacogenetics of leflunomide represents a promising, yet still exploratory, avenue of research in the context of personalized RA therapy. It emphasizes the need for larger, well-designed clinical trials and the development of standardized guidelines, which would be necessary before the potential implementation of such strategies in routine clinical practice. Full article

Background/Objectives: Neurological impairments in children with Cerebral Palsy (CP) often lead to altered muscle architecture and function, resulting in calf muscle contractures. Orthotic immobilization aims to promote muscle–tendon unit lengthening through sustained stretch but may also induce disuse atrophy. This study investigated whether combining immobilization with daily activity yields different effects on muscle strength and gait function compared with immobilization alone. Methods: Fourteen ambulant children with spastic CP and equinus deformity (8 unilateral, 6 bilateral; mean age 9.93 ± 3.0 years; GMFCS I: 10, GMFCS II: 4) participated in a 12-week randomized controlled trial. Participants were assigned to either continuous immobilization (23 h/day) using a dynamic ankle–foot orthosis or a combined protocol consisting of 14 h/day immobilization and 10 h/day of activity involving ankle mobility and calf muscle activation. Outcomes included isometric muscle strength, joint range of motion, gait parameters, and functional measures (Gait Outcomes Assessment List (GOAL) and the Paediatric Outcome Data Collection Instrument (PODCI)). Data were analyzed using linear mixed models with Bonferroni correction. Results: Significant time effects were observed for the knee angle at initial contact (IC), the ankle angle at IC, maximum dorsiflexion, and maximum dorsiflexion during swing. A significant group × time interaction was found only for hindfoot-tibia angle at IC. Within-group improvements were noted in activities of daily living, body image and self-esteem, and basic mobility. No significant changes were found for muscle strength or for most questionnaire subscales. Conclusions: The findings indicate time-related improvements in gait, with no consistent advantage of the combined intervention. Further studies with larger samples are needed to evaluate potential long-term effects. Full article

Dissimilar 7075-T6 and 6061-T6 aluminum alloy joints were fabricated using pulsed metal inert gas (P-MIG) welding with ER5356 filler wire. The effects of welding current (224 A, 234 A, and 244 A) on macro-morphology, microstructure, mechanical properties, and corrosion behavior were systematically investigated. As welding current increased, the top and bottom reinforcements first increased and then decreased, reaching maximum values at 234 A, while the front weld width exhibited the opposite trend. The weld zone consisted of equiaxed and dendritic grains, with partial remelting of AlFeMnSi intermetallic compounds observed in the heat-affected zones. The microhardness and tensile strength of the joints followed a similar trend of first decreasing and then increasing with welding current, achieving a maximum tensile strength of 203.9 MPa at 244 A, corresponding to 89.5% of the 6061-T6 base metal strength. Corrosion resistance varied across regions depending on the evaluation method. In intergranular corrosion tests, the 7075-HAZ showed the highest susceptibility due to grain boundary segregation of Mg and Zn. In electrochemical tests, the WZ exhibited the poorest corrosion resistance. For the 7075-HAZ, optimal corrosion resistance was achieved at 234 A, attributed to a stable passive film and uniform precipitate distribution. These findings provide valuable guidance for optimizing P-MIG welding parameters for dissimilar 7075/6061 aluminum alloy joints. Full article

Obesity is a complex, heterogeneous, chronic, and progressive disease, which correlates with an augmented risk of developing several comorbidities, including painful conditions, such as osteoarthritis. In this review, authors present for the first time the term meta-neuroinflammation for describing how the chronic, low-grade systemic inflammation, that occurs in obesity, may trigger oxidative stress and neuroinflammatory processes. Both the peripheral and the central nervous system are involved in neuroinflammation, leading to central sensitization and pain chronification, which leads to the observed increased incidence in obese patients of chronic pain syndromes, particularly osteoarthritis, low back pain, fibromyalgia, headache, and diabetic peripheral neuropathy. Possible mechanisms by which obesity may cause meta-neuroinflammation include adiposopathy, gut microbiota dysbiosis, and compromised integrity of blood–brain barrier, which could explain obesity-related depressive and neurodegenerative disorders. Preclinical data suggest the meta-neuroinflammation as a potential target of treatment in obese patients with degenerative joint disease. Based on these observations, targeted therapeutic strategies may include systemic administration of ultramicronized palmitoylethanolamide (um-PEA), well known for its neuroprotective, anti-neuroinflammatory, and analgesic actions, and comicronized PEA–rutin and hydroxytyrosol to restore intestinal eubiosis, with beneficial effects on body weight and mental disorders. Finally, Adelmidrol, as a PEA congener, could be considered for mitigating intra-articular meta-neuroinflammation in knee osteoarthritis. Full article

Background/Objectives: Muscle strength is a key determinant of functional capacity in older adults. However, measures such as handgrip strength may not fully reflect multi-joint force production, and the relevance of the Isometric Mid-Thigh Pull (IMTP) for functional and cardiorespiratory outcomes remains unclear. This study examined the associations between IMTP-derived peak force and functional and submaximal cardiorespiratory variables in independent older women. Methods: This cross-sectional study included 21 independent older women (72.6 ± 6.9 years). Maximal isometric strength (IMTP and handgrip), functional performance (TUG, 30-CST, 30-ACT), and submaximal cardiorespiratory variables were assessed. Associations were examined using Pearson’s correlation coefficients with false discovery rate (FDR) correction (q = 5%). Results: Absolute IMTP peak force was significantly related to handgrip strength (r = 0.77; q = 0.001) and PVT1 (r = 0.67; q = 0.007). Relative IMTP peak force was related to relative handgrip strength (r = 0.71; q = 0.002), VO₂VT2 (r = 0.60; q = 0.02), and inversely to COP (r = −0.56; q = 0.03). No significant relationships were observed with TUG, 30-ACT, or most cardiorespiratory variables. Conclusions: IMTP-derived peak force was related to selected neuromuscular and submaximal cardiorespiratory variables, but not to functional performance measures. These findings suggest that the IMTP may provide complementary information on neuromuscular status, although further studies are required. Full article

In close-range monocular visual measurement and cooperative target pose estimation, conventional planar targets are constrained by viewpoint changes and are prone to perspective distortion. Although spherical targets provide omnidirectional observability, their PnP-based pose estimation may still suffer from large errors under limited fields of view and sparse feature observations. To address this issue, this paper proposes an integrated visual measurement framework covering both high-precision spherical target construction and robust pose estimation. First, a composite marker layout based on adaptively scaled latitude–longitude topology is designed. To suppress cumulative distortion caused by long-sequence multi-view rigid registration, a center-to-pole point-cloud stitching strategy is developed, and multiple observations are fused using geometric-consistency weighting to accurately reconstruct the feature-point coordinate system of the target. Second, a joint optimization method is proposed by combining feature-point reprojection error with a contour center consistency constraint. Specifically, the theoretical contour center is predicted from the analytical projection model of the sphere and constrained to agree with the observed contour center fitted from the image. In addition, an SQPnP-based sequential reinitialization mechanism is introduced to improve robustness under sparse-point observations. Simulation results demonstrate that the proposed method achieves higher accuracy and robustness under continuous pose changes, sparse feature points, and different noise levels, compared with EPnP, EPnP+LM, LM, and SQPnP, while real-image experiments further demonstrate its practical feasibility. Full article

Mesenchymal stromal/stem cells (MSCs) are increasingly investigated as intra-articular therapies for equine osteoarthritis (OA), although most studies have focused on allogeneic or combination-based approaches. Evidence supporting the use of autologous MSCs as a stand-alone treatment remains limited. The present study evaluated the safety and clinical evolution following intra-articular administration of autologous muscle-derived MSCs (mdMSCs) in horses with naturally occurring chronic OA. Thirteen horses with confirmed clinical disease were included. Each affected joint received a single injection, with the administered cell dose adapted to joint size (1 × 10⁷ or 2 × 10⁷ cells). Clinical assessments were conducted at baseline and at 6 and 12 weeks post-treatment using the American Association of Equine Practitioners (AAEP) lameness scale, together with a joint inflammation score and a composite total clinical score (TCS). Clinical scores decreased over time, with statistically significant improvements observed at both follow-up time points. Seven of thirteen horses met the predefined responder criteria based on AAEP improvement, including complete resolution of lameness in several cases. The treatment was well tolerated, with only mild and transient local reactions that resolved without intervention. These results indicate that intra-articular administration of autologous mdMSCs is associated with clinically relevant improvement in horses with chronic OA. Full article

Lunar optical and synthetic aperture radar (SAR) imagery provide complementary information for characterizing the lunar surface. However, their joint use remains challenging because of substantial cross-modality differences and severe illumination constraints, particularly in polar regions. To address this challenge, we propose LS2ODiff (Lunar SAR-to-Optical Diffusion), a diffusion-based framework designed for SAR-to-optical image translation in lunar environments. LS2ODiff uses SAR observations as conditional guidance in the diffusion process and incorporates a partial-convolution strategy into the U-Net backbone to handle irregular invalid regions. In addition, self-attention modules are incorporated into the downsampling stages of the U-Net to model long-range spatial dependencies and enhance global structural consistency in complex lunar terrain. We further construct a dedicated paired dataset of the lunar south polar region by registering Chandrayaan-II DFSAR data with Lunar Reconnaissance Orbiter (LRO) Narrow-Angle Camera (NAC) imagery. Comparative experiments against Pix2Pix, CycleGAN, SynDiff, and ConDiff demonstrate that LS2ODiff achieves better visual fidelity and quantitative performance in terms of peak signal-to-noise ratio (PSNR), structural similarity index measure (SSIM), Fréchet inception distance (FID), and learned perceptual image patch similarity (LPIPS). These results demonstrate the potential of diffusion models for high-fidelity lunar image translation, offering new opportunities for polar terrain interpretation and future exploration missions. Full article

The Tibetan Plateau, formed by the Indian-Eurasian collision, is dissected by the north-south trending South Tibet Rift system, but the formation mechanism of these rifts within a continuing compressional setting remains debated. Using P-wave receiver functions and joint inversion with surface wave dispersion along a ~230 km broadband seismic profile crossing the Nyima-Tingri Rift (NTR) and Xianza-Dingjie Rift (XDR), we investigated the detailed crustal structure beneath the Himalayan and Lhasa terranes. Our results reveal three key findings: (1) The crustal thickness ranges from 60 to 80 km, with the XDR exhibiting a pronounced Moho uplift (~10 km) beneath the rift axis, whereas the Moho beneath the NTR remains flat and continuous, indicating contrasting evolutionary stages. (2) A mid-crustal low-velocity layer at ~30 km depth is consistently observed west of 87.2°E, suggesting the presence of partial melt or fluids that decouple upper crustal deformation from mantle flow. (3) A prominent intracrustal discontinuity at 50–70 km depth produces a “Moho doublet” pattern; we interpreted this as the subducted Indian lower crust in the Himalayan terrane but as the relict Tibetan Moho in the Lhasa terrane, reflecting progressive northward modification. Collectively, these observations demonstrate that the north-south structures in southern Tibet lack the deep structural characteristics of mature rifts and instead represent an “infant stage” of extension. Their formation is best explained by east-west crustal stretching driven by an ongoing north-south convergence and eastward flow of lower crustal and upper mantle materials rather than by classical lithosphere-scale rifting. Full article

Additive manufacturing through a laser cladding has been shown to be an effective technology for the mitigation of wear and rolling contact fatigue (RCF) of railway track. Small-scale tests have consistently shown that creating a thin layer of premium material on the tribo-active surface of the railhead vastly reduces wear and suppresses the onset of RCF due to the ratcheting mechanism being almost eliminated in comparison to standard rail material. Cladding reduces material plastic flow by 60% which is a cause of insulated track joint failure. This paper reports results from the first full-scale trials of additively manufactured laser clad layers on railway rails by studying their mechanical properties and microstructure. This is a vital step in safely progressing this technology from lab scale to network application. Tested full-scale insulated block joint (IBJ) specimens, clad with martensitic stainless steel (MSS) and Stellite 6, were sectioned, polished and etched and the microstructures of the clad, heat-affected zone and parent rail materials were inspected using optical and scanning electron microscopy (SEM) (Hitachi TM3030 plus, Tokyo, Japan). Residual stress was also measured. Cladding with MSS and Stellite 6 showed high wear and RCF resistance after the tests. Material flow was reduced with the clad layer applied. No defects such as porosity or large precipitates were observed in the heat-affected zone (HAZ), particularly close to the rail surface at the clad end which could act as a point of weakness. Residual stress states varied between materials, MSS being compressive (−344 MPa average) and Stellite 6 being tensile (+391 MPa average) which could have an impact on the fatigue life of the clad. This finding matches previous work, indicating that MSS may be preferable in the field, where bending of rails can occur. Overall, the work showed that laser cladding can provide a good solution to lipping issues and wear problems of rail in IBJs. Analysis in this work confirmed that the HAZ where clad meets the bulk rail at the surface has good structural integrity; however, this needs to be a focus of attention in field application of these layers. Full article

The reliable joining of ultra-thick aluminum alloy plates remains a critical technical challenge in modern industrial manufacturing, often hindered by defects such as porosity and excessive distortion associated with conventional fusion welding. The novelty of this work lies in the characterization of the intermediate layer overlapping zone in 110 mm ultra-thick plates, which has rarely been reported. The motivation is to overcome the limitations of single-pass FSW for thick plates, such as insufficient material flow and high tool forces, by adopting a sequential double-sided strategy. Furthermore, this technique may help moderate the through-thickness heat input variation, although no direct thermal measurements were made. The weld nugget zone consists of uniformly fine, recrystallized α-Al grains. In contrast, the heat-affected zone displays distinctly laminar grain structures. The overlapping regions within the intermediate layer, which undergo two thermal cycles, exhibit refined grain sizes. A well-defined interface is evident between the advancing-side weld nugget zone and the thermo-mechanically affected zone. The overall tensile strength of the FSW joint is approximately 81% of the base material, and the tensile specimen fractured at the interface between the thermo-mechanically affected zone and the heat-affected zone. Along the thickness of the weld joint, a “W”-shaped microhardness distribution is observed at the surface and subsurface, whereas the intermediate layer exhibits a distinct “V”-shaped profile. The lowest microhardness value is located in the intermediate layer overlapping area due to the insufficient heat input and limited grain growth in this region. In summary, under the specific welding parameters tested (130 rpm, 15 mm/min, 110 mm thick), double-sided friction stir welding produces defect-free joints in AA 5052-H32, suggesting its potential for thick-plate applications, offering a practical and effective solution for manufacturing high-performance aluminum alloy structures. Potential industrial applications include pressure vessels for chemical storage, ship hull structures, and heavy-duty transportation components where ultra-thick aluminum plates are required. Full article

This study experimentally investigates the evolution of natural frequencies of premium threaded connections under varying interface contact stiffness, aiming to establish a non-destructive vibration-based method for evaluating sealing contact conditions. The sealing interface features a sphere-on-cone configuration, and Hertzian contact theory is used to derive the contact pressure distribution, which shows a nonlinear increase in peak pressure with increasing normal load. Modal experiments were conducted under free–free boundary conditions using an impact hammer on a Φ88.9 mm × 6.45 mm P110 premium threaded connection. Three make-up torque levels (4081 N·m, 4393 N·m and 4691 N·m) were applied to create distinct contact states, and the first five orders of natural frequencies were extracted from the measured acceleration responses, using frequency response function (FRF) analysis with peak-picking identification. The results demonstrate that natural frequencies increase significantly with make-up torque, following a power-law relationship f = αT^β with R² > 0.97 for the first three modes. A critical torque range of 4200–4400 N·m is identified, below which frequencies rise sharply and above which the increase slows due to contact stiffness saturation. Lower-order modes are more sensitive to contact stiffness variations than higher-order modes. The findings confirm that natural frequency can serve as an effective non-destructive indicator for assessing tightening quality and detecting loosening in premium threaded connections, offering practical guidance for torque optimisation and structural health monitoring in oilfield operations. Although only three torque levels are used, the observed trend is physically consistent with contact mechanics theory and widely reported joint stiffening behavior. Therefore, the fitted relationship should be interpreted as a physically guided empirical model rather than a purely statistical fit. Full article

This paper proposes an enhanced adaptive unscented Kalman filter (SH-AUKF) method based on the Sage–Husa algorithm to address the issue of insufficient estimation accuracy for state parameters and road adhesion coefficients in distributed drive mining dump trucks under complex mining conditions. By integrating a seven-degree-of-freedom vehicle dynamics model with the Dugoff tire model, a collaborative observer is constructed for estimating state parameters and the four-wheel road adhesion coefficient. Through joint simulation verification using Trucksim–Matlab 2025b, it was demonstrated that under sinusoidal steering, step steering, and varying road adhesion coefficients (0.3~0.7), the root mean square error (RMSE) of longitudinal vehicle speed, slip angle, and yaw rate estimation using SH-AUKF was significantly reduced compared to the traditional UKF. Additionally, the estimation error of the four-wheel road adhesion coefficient was decreased by 8~26%. This has significant application value for improving the automation level of mining transportation. Full article