Search Results (471)

The scaphoid is the most commonly fractured carpal bone. Headless compression screws became the gold standard for fixation, but the ideal screw diameter remains debated. This study investigates the relative benefit of using a larger screw diameter to improve stability in typical scaphoid fractures. It also examines the effects of preload and screw length on mechanical behaviour. A finite element (FE) model of a mid-waist scaphoid fracture was created. Screws from Medartis (1.7 mm, 2.2 mm, and 3.0 mm diameter; 23 mm length) were placed along the longitudinal axis. Boundary and loading conditions matched prior studies. Interfragmentary displacement (IFD) and von Mises stress were compared across screw sizes. The effects of screw length and preload were also evaluated. Maximum in-plane IFD was 2.08 mm (1.7 mm screw), 0.53 mm (2.2 mm), and 0.27 mm (3.0 mm). The 1.7 mm screw exceeded the scaphoid’s average ultimate stress (60.51 MPa). Increasing preload reduced IFD, especially above 60 N. Screws longer than 1.5 times the mid-waist diameter offered no added benefit. Larger screws provide better biomechanical fracture stability. However, the gain from 2.2 mm to 3.0 mm is minor, while 1.7 mm screws lack sufficient strength. The 2.2 mm screw offers a good balance of stability and bone preservation, making it the preferred choice. Full article

To address the persistent challenges of substantial land occupation, intricate construction sequencing, and extended project timelines inherent to conventional substation accident oil sumps, this research introduces a novel integrally prefabricated circular cross-section oil containment structure. The study establishes a finite element representation of this prefabricated system to systematically examine structural deformation mechanisms and failure patterns under combined hydrostatic and geostatic loading scenarios. Through parametric analysis of the oil tank structure, the influences of longitudinal reinforcement diameter, thickness–diameter ratio, height–diameter ratio, and concrete-strength grade on the mechanical characteristics of the structure are explored. Utilizing the response surface methodology for the parametric optimization in finite element analysis, a comprehensive optimization of critical geometric design variables is conducted. These results indicate that longitudinal reinforcement diameter and concrete-strength grade exert negligible influence on concrete stress except for stress increase under internal pressure, with higher concrete grades. The thickness-to-diameter ratio dominantly regulates structural responses: response surface optimization achieved 12% stress reduction and 14% displacement mitigation at 220 mm wall thickness under internal pressure, despite a 4% stress increase under external loading. Height-dependent effects require specific optimization, with 18% stress reduction beyond 3000 mm under external pressure but 20% stress increase at 3400 mm under top loads. Geometric refinements enable 34–50% displacement reduction in critical zones, providing validated references for prefabricated oil tanks. Full article

Narrative review synthesizes the most current literature on the SARS-CoV-2 XEC variant, focusing on its genomic evolution, immune evasion characteristics, epidemiological dynamics, and public health implications. To achieve this, we conducted a structured search of the literature of peer-reviewed articles, preprints, and official surveillance data from 2023 to early 2025, prioritizing virological, clinical, and immunological reports related to XEC and its parent lineages. Defined by the distinctive spike protein mutations, T22N and Q493E, XEC exhibits modest reductions in neutralization in vitro, although current evidence suggests that mRNA booster vaccines, including those targeting JN.1 and KP.2, retain cross-protective efficacy against symptomatic and severe disease. The XEC strain of SARS-CoV-2 has drawn particular attention due to its increasing prevalence in multiple regions and its potential to displace other Omicron subvariants, although direct evidence of enhanced replicative fitness is currently lacking. Preliminary analyses also indicated that glycosylation changes at the N-terminal domain enhance infectivity and immunological evasion, which is expected to underpin the increasing prevalence of XEC. The XEC variant, while still emerging, is marked by a unique recombination pattern and a set of spike protein mutations (T22N and Q493E) that collectively demonstrate increased immune evasion potential and epidemiological expansion across Europe and North America. Current evidence does not conclusively associate XEC with greater disease severity, although additional research is required to determine its clinical relevance. Key knowledge gaps include the precise role of recombination events in XEC evolution and the duration of cross-protective T-cell responses. New research priorities include genomic surveillance in undersampled regions, updated vaccine formulations against novel spike epitopes, and long-term longitudinal studies to monitor post-acute sequelae. These efforts can be augmented by computational modeling and the One Health approach, which combines human and veterinary sciences. Recent computational findings (GISAID, 2024) point to the potential of XEC for further mutations in under-surveilled reservoirs, enhancing containment challenges and risks. Addressing the potential risks associated with the XEC variant is expected to benefit from interdisciplinary coordination, particularly in regions where genomic surveillance indicates a measurable increase in prevalence. Full article

Deep-sea navigation represents the future trend of maritime navigation; however, complex seakeeping conditions often lead to unconventional ship attitudes. Conventional calculation methods are insufficient for accurately assessing hull performance under heeled or extreme trim conditions. Drawing inspiration from Bonjean curve principles, this study proposes a Quasi-Bonjean (QB) method to compute ship performance elements in arbitrary attitudes. Specifically, the QB method first constructs longitudinally distributed hull sections from the Non-Uniform Rational B-Spline (NURBS) surface model, then simulates arbitrary attitudes through dynamic waterplane adjustments, and finally calculates performance elements via sectional integration. Furthermore, an Adaptive Surface Tessellation (AST) method is proposed to optimize longitudinal section distribution by minimizing the number of stations while maintaining high geometric fidelity, thereby enhancing the computational efficiency of the QB method. Comparative experiments reveal that the AST-generated 100-station sections achieve computational precision comparable to 200-station uniform distributions under optimal conditions, and the performance elements calculated by the QB method under multi-attitude conditions meet International Association of Classification Societies accuracy thresholds, particularly excelling in the displacement and vertical center of buoyancy calculations. These findings confirm that the QB method effectively addresses the critical limitations of traditional hydrostatic tables, providing a theoretical foundation for analyzing damaged ship equilibrium and evaluating residual stability. Full article

The paper presents results of experimental research on tyre–road contact stress distributions, measured indoors for a motorsport slick tyre. The triaxial contact stress distributions have been measured using the complex transducer containing a transversal array of 30 sensing pins covering the entire contact patch width. Wheel displacement in the longitudinal direction was measured using a rotary encoder. The parameters allocated for the experimental programme have included different values of tyre inflation pressure, vertical load, camber angle and toe angle. All measurements were performed at low longitudinal speed in free-rolling conditions. The influence of tyre functional parameters on the contact patch shape and size has been discussed. The stress distributions on each orthogonal direction are presented in multiple formats, such as 2D graphs in which the curves show the stresses measured by each sensing element versus contact length; surfaces with stress values plotted as vertical coordinates versus contact patch length and width; and colour maps for stress distributions and orientations of shear stress vectors. The effects of different parameter types and values on stress distributions have been emphasised and analysed. Furthermore, the magnitude and position of local extreme values for each stress distribution have been investigated with respect to the above-mentioned tyre functional parameters. Full article

Under prolonged loading and various environmental factors, the performance of stay cables gradually deteriorates, which impacts the safety of the bridge structure. To investigate the influence of cable damage on the static performance of cable-stayed bridges, a finite element model of a cable-stayed bridge with damaged cables was established. The element death method is used to simulate cable damage, examining the impact of various damage scenarios on the static performance of the cable-stayed bridge. The objective is to identify cable locations that have a greater impact on the structure, providing a basis for assessing the bridge’s safety and developing cable replacement strategies. The research indicates that damage to long cables has a more significant impact on the static performance of the cable-stayed bridge compared to damage to short cables. Additionally, damage to the side span cables has a more pronounced effect on the structure than damage to the mid-span cables. The influence of cable damage on cable forces is primarily reflected on the same side of the cable plane within the same bridge tower as the damaged cable. Changes in cable forces result in variations in the deflection of the main girder and the displacement of the main tower. When multiple cables are damaged, the impact on the static performance of the structure is similar to that of single-cable damage. In instances of longitudinal symmetric damage and adjacent cable impairment, the cables transition into a critical state, resulting in more pronounced alterations in the deflection of the main girder and the displacement of the main tower. Original symmetric damage has a relatively small impact on the static performance of the entire bridge, so it is recommended to adopt a symmetric approach for cable replacement projects. Considering the impact of damage to a single cable and multiple cables on the static structure, it is possible to initially determine the location and extent of the cable damage. Based on the damage patterns, a cable replacement plan can be designed. It is recommended to use a symmetry-based approach for the cable replacement, as this method results in minimal impact on the overall static performance of the bridge, thereby ensuring the safety of the bridge structure. Full article

The behavior of the cast-in-place continuously reinforced concrete (CRC) bus pad applied to bus stop pavement in a central bus-only lane was experimentally analyzed under environmental and moving vehicle loads, and the early-age performance of the CRC bus pad was evaluated using experimental data and finite element analysis results. Using various measurement sensors, the concrete slab strain, longitudinal steel bar strains, horizontal and vertical displacements, and crack behavior of the CRC bus pad due to environmental loads were measured, and the dynamic responses of the concrete slab and steel bars due to moving vehicle loads were also measured. Additionally, a method for converting strain gauge measurements of a cracked concrete slab to the strain of an uncracked concrete slab was also proposed. Under environmental loads, the range of stresses acting on the steel bars and the bond between concrete and steel bars were analyzed to be appropriate for ensuring excellent performance of the CRC bus pad. The crack widths and vertical and longitudinal displacements of the CRC bus pad were found to have no effect on the pavement performance. Within the vehicle velocity range used in this experiment, the strains of the slab and steel bars as the vehicle passed through the CRC bus pad were virtually independent of the vehicle velocity and were within a range that did not cause any reduction in pavement performance. This study confirmed that the CRC bus pad has excellent performance and can replace asphalt concrete bus stop pavement or jointed concrete bus pad. Full article

The central buckle is essential for maintaining longitudinal stability in suspension bridges. However, conventional steel buckles are often excessively stiff, leading to stress concentration and insufficient durability. Moreover, they tend to perform poorly under fatigue loading conditions. This study proposes a novel flexible central buckle system based on a Carbon Fiber-Reinforced Polymer (CFRP) to address these limitations. This study proposes a novel flexible central buckle system based on Carbon Fiber-Reinforced Polymer (CFRP) to address these limitations. Taking the long-span Shiziyang Suspension Bridge as a case study, a finite element model is developed to investigate the effects of CFRP central buckles with eight different stiffness levels on the static and dynamic responses of the bridge. The results indicate that a CFRP central buckle with a low elastic modulus achieves comparable displacement control performance to that of traditional steel buckles, while inducing significantly lower internal forces, demonstrating strong potential as a substitute. Based on this finding, a coordinated control strategy combining the CFRP central buckle with end-span restraining devices is proposed. This integrated system reduces midspan displacement and central buckle internal force by 61.1% and 49.8%, respectively. Considering both performance and cost-efficiency, a low-modulus CFRP material such as T300 is recommended. The proposed approach offers a new and effective solution for longitudinal control in ultra-long-span suspension bridges. Full article

Friction behaviour at the wheel–rail interface is of critical importance for railway operations and maintenance and is generally characterised by creep curves. The V-Track test rig was used in this study to measure both the lateral and longitudinal creep curves with uncontaminated dry interface conditions, utilising contact pressures representative of operational railway wheel–rail systems. The novelties of this study are threefold. 1. With proper representations of train/track components, the V-Track tests revealed the effects of structural dynamics on measuring wheel–rail creep curves in real life. 2. Pure lateral and longitudinal creepage conditions were produced with two distinct experimental principles—displacement- and force-controlled—on the V-Track, i.e., by carefully controlling the angle of attack and the traction/braking torque, respectively, and thus the coefficient of friction from lateral and longitudinal creep curves measured on the same platform could be cross-checked. 3. The uncertainties in the measured creep curves were analysed, which was rarely addressed in previous studies on creep curve measurements. In addition, the measured creep curves were compared against the theoretical creep curves obtained from Kalker’s CONTACT. The influence of wheel rolling speed and torque direction on the creep curve characteristics was then investigated. The measurement results and findings demonstrate the reliability of the V-Track to measure wheel–rail creep curves and study the wheel–rail frictional rolling contact. Full article

Background/Objectives: This cross-sectional analytical study investigated the relationship between the craniofacial morphology, condylar displacement, and degenerative changes in the temporomandibular joints (TMJs) in adult patients with class II skeletal malocclusion. To compare cephalometric variables, joint space dimensions, and centric slide measurements between patients with and without CBCT-confirmed TMJ degenerative alterations. Methods: Sixty adults with class II malocclusion were divided into two equal groups (n = 30) based on the presence or absence of TMJ degenerative changes on CBCT. Joint spaces were measured, condylar displacement was evaluated using a condylar position indicator (CPI), and cephalometric analysis was performed in both maximal intercuspation and centric relation. Statistical comparisons were performed using t-tests, chi-squared tests, and Pearson’s correlation analysis. Significance was set at p < 0.05. Results: Patients with degenerative TMJ changes exhibited significantly greater overjet (p = 0.0001) and a trend toward increased ANB angles (p = 0.055). The superior joint space was reduced on the right side (p = 0.031). Condylar displacements ≥ 2 mm were more frequent in the affected group and correlated with sagittal cephalometric discrepancies (45% vs. 24% in controls). Conclusions: Aggravated skeletal class II malocclusion with increased overjet could be associated with TMJ degenerative changes. CR-based cephalometry and CBCT evaluation may aid in diagnostic assessment, but longitudinal studies are needed to confirm the clinical relevance. Full article

The unloading effect induced by foundation pit excavation leads to soil deformation, which may adversely affect the underlying tunnel. Foundation pit excavation is a three-dimensional (3D) deformation process, whereas most existing methods are based on a two-dimensional (2D) plane assumption. To improve conventional 2D analysis methods, this study considers the influence of the actual construction sequence on tunnel deformation. A 3D analytical method for evaluating tunnel deformation and stress induced by foundation pit excavation is proposed, based on the image source method and the rotational dislocation-coordinated deformation model. The proposed method is validated through comparative analysis with other methods using monitoring data from three engineering cases. Furthermore, the study examines and discusses the impact of excavation sequences on the final longitudinal displacement of the tunnel. The results indicate that the proposed method provides more accurate predictions of tunnel deformation induced by foundation pit excavation in actual projects. Staged and segmented excavation reduces bottom heave of the foundation pit, thereby mitigating its impact on the underlying tunnel. When the segmentation efficiency is positive, increasing the number of excavation blocks contributes to better tunnel deformation control. However, when the segmentation efficiency is negative, an increase in excavation blocks has an insignificant effect on deformation control or leads to excessive construction workload. Full article

With the continuous development of maglev transportation technology, medium–low-speed maglev trains have been widely implemented in many countries. However, due to the limitations of existing specifications, the stiffness limit values of the large-span main girders used in medium–low-speed maglev trains have not been unified. To address this issue, this study takes a specific bridge on a dedicated maglev line as an example and uses self-developed software to model the vehicle–bridge dynamic system. The natural vibration characteristics and vehicle–bridge coupling vibration response of the bridge are calculated and analyzed. Based on this, the influence of pier top stiffness on the dynamic characteristics of a typical medium–low-speed maglev train–bridge system under different working conditions is investigated, with a focus on the lateral line stiffness at the pier top. The results show that vehicle speed has no significant effect on the lateral displacement of the main girder, the lateral displacement of the pier top, the lateral acceleration of the pier top, and the transverse and longitudinal angles of the beam end, and no obvious regularity is observed. However, in the double-track operating condition, the vertical deflection of the main girder is significantly higher than that in the single-track operating condition. As the lateral linear stiffness at the pier top increases, the fundamental frequency of the bridge’s lateral bending vibration gradually increases, while the fundamental frequency of longitudinal floating gradually decreases. The lateral displacements, including those of the main girder, pier top, and beam ends, all decrease, whereas the lateral and vertical vibration accelerations of the main girder and the train are less affected by the lateral stiffness at the pier top. Full article

Background: Toggling of the short cephalomedullary nail is an understudied phenomenon characterized by a change in the longitudinal axis of the nail in relation to the longitudinal axis of the femoral medullary canal, with subsequent potential loss of reduction. This retrospective study aims to examine the incidence and impact of toggling of short cephalomedullary nails in cases with wide femoral canals. Methods: One thousand two hundred fifty-six (1256) cases that received short proximal femoral nails for intertrochanteric fractures were reviewed. Of them, 101 cases that had wide femoral canals (≥15 mm) and a minimum radiographic follow-up of 6 weeks were included in this study. Outcome measures included nail toggling, varus malunion and revision surgery. Results: After a mean radiographic follow-up of 53.5 weeks, sixteen cases (15.8%) showed significant nail toggling of more than 4 degrees and had subsequent varus displacement of the fracture. In all 16 cases, there was deficient proximal nail fixation, in the form of either a lag device not engaging the lateral wall (2 cases), lateral proximal femoral wall fracture/incompetency (7 cases), or a combination of the two factors (7 cases). Despite this, all sixteen cases achieved fracture union. Five additional cases had complications related to poor initial reduction (four cases) or femoral head avascular necrosis (one case). The other 80 cases had minimal (0–4 degrees) nail toggling and healed without varus malunion, and none of them required revision surgery. Conclusions: Short cephalomedullary nails may toggle in patients with wide femoral canals. The effect of femoral canal width on nail movement and subsequent varus malunion may be abolished when the lag device engages the lateral proximal femoral cortex, and the lateral cortical bone is intact. In patients with wide femoral medullary canals or cases with proximal lateral femoral cortical fracture, the utilization of long or intermediate length cephalomedullary nails may be a more viable option. Full article

Observations indicate a robust relationship between the magnitude of El Niño events and the longitudinal displacement of the eastern edge of the Western Pacific Warm Pool (WPWP). Are the state-of-the-art coupled models also capturing this strong relationship? Here, we address this question by analyzing the Coupled Model Intercomparison Project Phase 6 (CMIP6) models. The results show that 31 out of 33 models replicate the observed strong correlation between El Niño magnitude and WPWP displacement. However, the models overestimate both El Niño strength and the extent of eastward WPWP movement, while underrepresenting the inter-event variability. These findings support the notion that El Niño may be largely regarded as an eastward extension of the WPWP, while also highlighting some model–observation discrepancies that may warrant particular attention. Full article

In the context of global population aging, identifying reliable, objective tools to assess physical function and postural stability in older adults is increasingly important to mitigate fall risk. This study presents a non-contact platform that uses a Microsoft Azure Kinect depth camera to evaluate functional performance related to lower-limb muscular capacity and static balance through self-selected depth squats and four progressively challenging stances (feet apart, feet together, semitandem, and tandem). By applying markerless motion capture algorithms, the system provides key biomechanical parameters such as center of mass displacement, knee angles, and sway trajectories. A comparison of older and younger individuals showed that the older group tended to perform shallower squats and exhibit greater mediolateral and anteroposterior sway, aligning with age-related declines in strength and postural control. Longitudinal tracking also illustrated how performance varied following a fall, indicating potential for ongoing risk assessment. Notably, in 30 s balance trials, the first 10 s often captured meaningful differences in stability, suggesting that short-duration stance tests can reliably detect early signs of imbalance. These findings highlight the feasibility of low-cost, user-friendly depth-camera technologies to complement traditional clinical measures and guide targeted fall-prevention strategies in older populations. Full article