Search Results (3,861)

Background/Objectives: Inflammatory bowel disease (IBD) is associated with reduced areal bone mineral density (aBMD) and an increased risk of osteoporosis and fragility fractures. Although exercise improves bone health in the general population, its effects on aBMD in adults with IBD are unclear. This systematic review aimed to evaluate the effects of structured exercise interventions on aBMD in adults with IBD and to assess the certainty of the evidence. Methods: We conducted a systematic review in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and the Cochrane Handbook. Searches were performed in CENTRAL, MEDLINE, Scopus, and Web of Science from inception to November 2025. We included randomized controlled trials comparing structured exercise interventions with usual care, no structured exercise or no intervention in participants aged 16 years and older with IBD. The primary outcome was aBMD; physical activity was a secondary outcome. Risk of bias was assessed using the Cochrane Risk of Bias tool (RoB 2.0), and certainty of evidence was evaluated using Grading of Recommendations Assessment, Development and Evaluation (GRADE). The review protocol was registered in International Prospective Register of Systematic Reviews (PROSPERO) CRD42024617200. Results: Two randomized controlled trials (n = 164), both conducted exclusively in adults with Crohn’s disease, met the inclusion criteria. Combined impact and resistance training for 6 months was associated with greater lumbar spine aBMD compared with usual care, while hip outcomes were not consistently improved. A 12-month low-impact exercise program compared with no intervention suggested greater trochanter aBMD gain among fully compliant participants, but intention-to-treat between-group differences were not statistically significant across skeletal sites. Due to heterogeneity in interventions and reporting, meta-analysis was not performed. Overall certainty of the evidence was very low because of methodological limitations and imprecision. Conclusions: We are very uncertain about the effect of exercise interventions on aBMD in adults with IBD. Current randomized evidence is limited to adults with Crohn’s disease and is insufficient to determine the optimal exercise modality, frequency, intensity, progression, or loading characteristics for improving bone health. Well-designed trials across IBD phenotypes are needed to clarify the role of exercise in bone health management in IBD. Full article

Earthquakes may cause severe damage to engineering structures in the seismogenic fault zone. In near-fault regions, ground motions on the two sides of a fault exhibit significant asymmetry in terms of permanent displacement, velocity pulse, and dynamic displacement amplitude. Taking the Xianglu Mountain Tunnel in the southwest of China as the engineering object, this study designed scaled fault-crossing tunnel-surrounding rock test models and conducted a series of quasi-static and dynamic model tests using a dual-shaking table system with non-uniform ground motion input. The effects of three different earthquake action modes on the responses of tunnel engineering structures crossing seismogenic faults were investigated through five static and dynamic earthquake action modes. The test results indicate that considering only the dynamic effect of ground motion or only the static effect of permanent displacement due to fault dislocation will underestimate the seismic response and damage degree of the surrounding rock and tunnel structure. However, the contribution of dynamic effects of ground motion to tunnel failure is much smaller than that of static fault dislocation. The magnitude of permanent displacement from fault dislocation, the peak displacement of non-uniform ground motion time history, and the peak relative displacement are all important factors affecting the deformation of surrounding rock and the strain of tunnel structures. Traditional static analysis methods will lead to an underestimation of the damage risk of tunnel structures. Compared with the non-uniform earthquake action mode, the deformation within the fracture zone under the static action mode is underestimated by approximately 6.39%, and the peak tensile strain under the static action mode underestimates the damage risk by approximately 40%. Full article

Prestressed centrifugal concrete hollow square piles often require on-site splicing, and the structural reliability of the pile connection largely governs the performance of the assembled pile. To address the limitations of conventional welded and mechanical joints, a section steel plug-in composite joint combining central grouted steel tube anchorage and peripheral end-plate welding was developed and experimentally evaluated. Flexural and shear tests were conducted on 12 full-scale specimens, including pile shaft specimens and joint specimens with cross-sectional side lengths of 400, 500, and 600 mm. The flexural and shear behavior of the jointed specimens was assessed in terms of bearing capacity, load–deflection response, crack development, and failure mode by comparison with the corresponding pile shafts. Under flexural loading, the pile shaft specimens mainly failed by fracture of prestressing steel bars at midspan, whereas the joint specimens failed near the loading point by prestressing steel fracture, indicating that the critical failure region shifted away from the joint core. The flexural capacities of the joint specimens reached about 92–97% of those of the corresponding pile shafts. Under shear loading, both pile shaft and joint specimens mainly exhibited diagonal compression failure in the flexural–shear region, while no obvious damage was observed in the joint core region. The shear capacities of the joint specimens were about 103–130% of those of the corresponding pile shafts. These results indicate that the proposed section steel plug-in composite joint can effectively maintain flexural resistance while enhancing shear performance. The central steel tube, hardened grout, anchorage reinforcement, and peripheral welds jointly contributed to the integrity and force transfer capacity of the connection, showing favorable potential for engineering application in prestressed centrifugal concrete hollow square pile splicing. Full article

Fatal free falls (FFF) represent a distinct form of blunt force trauma and pose a significant challenge in forensic investigations, particularly in estimating fall height and differentiating between accidental and suicidal events. Postmortem computed tomography (PMCT) enables detailed assessment of skeletal injuries, including quantitative evaluation of skull fracture patterns. Total Cranial Fracture Length (TCFL), derived from three-dimensional CT skull fracture scoring (3D-CT-SF), has been proposed as an objective indicator of impact severity; however, available evidence remains limited. This study aimed to assess the relationship between TCFL and fall height in fatal free falls and to evaluate the influence of selected anthropometric and biomechanical variables on cranial fracture severity. A retrospective analysis of 76 fatal free-fall cases examined between 2016 and 2024 was conducted using PMCT and autopsy data. TCFL was measured on three-dimensional volume-rendered CT reconstructions of calvarial fractures. Statistical analyses were performed for the entire cohort and separately for accidental and suicidal falls. No significant correlation between TCFL and fall height was observed in the overall cohort or among suicide cases. In contrast, a significant negative correlation between TCFL and fall height category was identified in accidental falls. TCFL showed significant positive correlations with body mass, body mass index (BMI), and kinetic energy, particularly in the suicide subgroup. TCFL is a promising objective parameter for assessing the severity of cranial injury in fatal free-fall cases. While its utility in estimating fall height appears limited in suicidal falls, TCFL may support forensic interpretation of fall dynamics and contribute to distinguishing the manner of death, especially in accidental cases. Further studies in larger, more diverse populations are warranted. Full article

This study examines the microstructural characteristics and tensile properties of autogenous orbital gas tungsten arc (GTA) circumferential butt welds produced on commercially rolled 304 stainless steel seam pipes (outer diameter 38.1 mm, wall thickness 2.0 mm) for high-purity fluid distribution systems. A three-segment current profile was employed using an AMI 8-4000 orbital system, with peak currents of 70, 67, and 65 A for the penetration, remelting, and downslope (crater-fill) segments, respectively, under high-purity Ar (99.999%) shielding with back purging. Electron backscatter diffraction (EBSD) analysis, including image quality (IQ), inverse pole figure (IPF), and kernel average misorientation (KAM) mapping, showed that the weld metal consists of epitaxially grown columnar austenite grains strongly oriented along the solidification direction, whereas the heat-affected zone (HAZ) exhibits finer equiaxed grains with an increased Σ3 twin boundary fraction and elevated low-angle boundary fraction, indicative of partial recrystallization. Only sparse, discontinuous δ-ferrite stringers were detected in the fusion zone, and no non-metallic inclusions were observed on fracture surfaces, supporting the weld metal’s suitability for semiconductor-grade cleanliness. Vickers microhardness profiles revealed modest hardness differences (typically within 10–20 HV) between the weld metal, HAZ, and base metal, with no pronounced HAZ softening. Cross-weld tensile tests conducted in accordance with ASTM E8/E8M-22 yielded yield strengths above 200 MPa, ultimate tensile strengths of 650–680 MPa, and total elongations approaching 40%, comparable to the as-received pipe. Scanning electron fractography confirmed fully ductile failure via microvoid coalescence without evidence of cleavage, intergranular decohesion, or weld-defect-induced embrittlement. Collectively, these results demonstrate that the three-segment autogenous orbital GTAW procedure produces structurally sound, particle-clean joints suitable for 304 stainless steel seam pipes used in high-purity industrial piping. Full article

Reservoir simulation of unconventional resources has become increasingly important due to advancing technologies and the growing demand for efficient hydrocarbon recovery. These reservoirs present distinct challenges related to characterization, multiphase flow behavior, and production forecasting. Reservoir simulation workflows integrate geological, petrophysical, and fluid-property data to better represent subsurface behavior. As hydraulic fractures provide the primary pathways for fluid flow in unconventional reservoirs, accurately modeling fracture geometry and conductivity is essential for reliable reserves estimation, production forecasting, and field development planning. Fracture conductivity is controlled by several coupled processes, including fracture propagation, proppant transport, proppant placement, and stress-dependent permeability, which makes its accurate estimation challenging. Although commercial hydraulic fracturing software incorporates geomechanical and particle-transport models to predict conductivity, their outputs are not always directly compatible with reservoir simulation models and often fail to reproduce observed production trends. This study implements various conductivity models in commercial software and evaluates their performance within reservoir simulation. A fracture model built from publicly available data is integrated into a mechanistic reservoir simulation framework to assess the impact of different conductivity models on pressure distribution, depletion behavior, and production profiles. The results provide practical insights into conductivity modeling approaches that balance realism with applicability in reservoir simulation workflows. Different conductivity models, including constant, expanded conductive zone, linear, and multiple exponential forms, were evaluated. It was found that conductivity variation directly impacts well profiles, ultimate recoveries and well spacing in unconventional reservoir development. Full article

Understanding the movement behavior of upper blocks along rock joints or weak planes is crucial for the geological hazard forecast and prediction. This paper presents experimental and numerical investigations of a saw-tooth joint under shear and normal load conditions. Multi-stage direct shear tests under different normal load conditions were conducted using a direct shear box apparatus. The reverse dilation behavior of the upper specimen was observed by measuring the normal displacement at the four corners of the upper block. Laboratory test results show that, under lower normal loads, the normal displacement of the upper specimen on the applied shear force side initially decreases (settlement), while the settlement reverses to heave (dilation) when the shear displacement reaches a certain value. However, the settlement reverse behavior does not occur under large normal loads. Corresponding numerical simulation confirms that this settlement reversal is controlled by the specimen fracturing. The saw-tooth asperities are sheared off under a large normal load, while the upper specimen climbs along the slope of the bottom specimen under lower normal loads. Consequently, the changes in contact area, interface normal stress, interface shear stress, and normal displacement of the joint differ significantly between large and low normal load conditions. This research deepens our understanding of the shear-induced dilation and fracture behavior of saw-tooth joints, and the results can provide guidelines for evaluating the stability of geological rock mass. Full article

This study investigates the flow stress behavior of Z-shaped steel wire used in cable sealing applications, over a temperature range of 20–500 °C and a strain rate range of 10⁻⁴ to 3000 s⁻¹. The primary objective is to establish reliable constitutive data to support accurate numerical simulations in relevant engineering contexts. To this end, quasi-static tensile tests, high-temperature tensile tests, and high-strain-rate dynamic compression tests were conducted using a high–low temperature electronic universal testing machine and a split Hopkinson pressure bar system. The true stress–strain responses were obtained, and the corresponding mechanical properties were systematically analyzed. Experimental results show that at room temperature (20 °C) and within the low strain rate range (10⁻⁴–10⁻¹ s⁻¹), the flow stress is insensitive to strain rate variations. However, following yielding, the slope of the flow stress curve increases noticeably with accumulating strain, indicating deformation behavior governed predominantly by strain hardening. Under high-strain-rate conditions at room temperature (20 °C, 10² to 10³ s⁻¹), the yield stress increases with increasing strain rate, revealing a pronounced strain rate sensitivity. At elevated temperatures combined with a low strain rate (300–500 °C, 10⁻³ s⁻¹), both the yield stress and the overall flow stress decrease markedly as the temperature rises, demonstrating significant thermal softening behavior. The microstructure and fracture of Z4 steel wire were observed by SEM to systematically investigate the effects of strain rate and temperature on its microstructural characteristics, thereby revealing the micro-mechanism of the material’s flow stress. Based on these experimental observations, a Johnson–Cook constitutive model was developed for the Z-shaped steel wire used in cable sealing applications. Validation results confirm that the model accurately captures the flow stress evolution of the material under coupled temperature and strain rate conditions. Full article

This work investigates the Mode I fracture behavior of adhesive joints manufactured from unidirectional carbon fiber-reinforced epoxy composites (CFRP) under static and fatigue loading. Specimens were exposed to two degradation environments: hygrothermal conditions (60 °C, 70% RH) and saline conditions (35 ± 2 °C, 89% RH), for 1 and 12 weeks, and compared with non-exposed material. Double Cantilever Beam (DCB) tests were conducted to evaluate the influence of aging on fracture toughness. Thermal (Differential Scanning Calorimetry, DSC) and spectroscopic (Fourier Transform Infrared Spectroscopy, FTIR) analyses were performed to identify degradation mechanisms. DSC results showed no significant variation in glass transition temperature (T_g) under saline exposure, whereas hygrothermal aging increased T_g, indicating post-curing effects. FTIR analysis revealed moisture uptake and oxidation under saline conditions, while hygrothermal exposure mainly led to structural rearrangement. Critical energy release rate (G_IC) values were used to define fatigue test conditions, enabling the construction of fatigue initiation (ΔG–N) and crack propagation (G–da/dN) curves. A Weibull-based model was applied to describe fatigue initiation behavior. Results show that saline exposure promotes progressive degradation, whereas hygrothermal conditions may enhance performance due to post-curing effects. Full article

Background: Clinical controversy persists regarding the optimal weight-bearing strategy for elderly patients following hip fractures. Whilst early unrestricted weight-bearing may improve functional outcome and reduce the risk of bed-related complications, concerns about implant stability and failure often lead clinicians to adopt restricted weight-bearing protocols. To address this, we conducted a systematic review and meta-analysis to identify the effects of unrestricted weight-bearing compared with restricted weight-bearing on clinical outcomes in this patient population. We hypothesized that unrestricted weight-bearing may be associated with lower all-cause mortality without increasing postoperative complications, reoperation rates or length of hospital stay (LOS). Methods: This systematic review was conducted based on a study protocol registered on the PROSPERO platform and reported strictly in accordance with the PRISMA guidelines. We included clinical studies involving patients aged ≥65 years with hip fractures undergoing surgical treatment that directly compared the effects of different postoperative weight-bearing strategies on outcomes. Patients were further classified into unrestricted and restricted weight-bearing groups according to the postoperative weight-bearing protocols reported in each study. The primary outcome was all-cause mortality. Secondary outcomes included postoperative complications, reoperation rates, and LOS. A random-effects model was used for meta-analysis. Dichotomous variables were expressed as risk ratios (RRs), continuous variables as mean differences (MDs), and study heterogeneity was assessed using the I² statistic. The certainty of evidence of each outcome was assessed by using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Results: Ten studies (one randomized controlled trial and nine cohort studies) were included with 5806 patients in total. Extra-capsular fractures (intertrochanteric/subtrochanteric fractures) were the most common, with 3694 patients, followed by femoral neck fractures, with 1929 patients. Unrestricted weight-bearing was significantly associated with lower long-term mortality compared with restricted weight-bearing (RR = 0.67, 95% CI 0.51–0.88, p = 0.004, I² = 34%; 95% PI 0.52–0.83), with an absolute risk difference of −0.10%. Short-term mortality did not differ significantly in the primary analysis (RR = 0.58, 95% CI 0.14–2.34, p = 0.44, I² = 70%; 95% PI 0.00–126.98). Furthermore, the corresponding absolute risk difference was only −0.03%. No significant differences were observed for short-term complications, long-term complications, reoperation risk, or LOS between the two groups (all p > 0.05). GRADE assessment showed low certainty of evidence for long-term mortality and short-term complications, and very low certainty of evidence for the remaining outcomes. Conclusions: This meta-analysis suggests that unrestricted weight-bearing may be a feasible postoperative rehabilitation approach in selected patients. However, the results should be interpreted with caution. Further well-designed prospective studies are required to confirm these findings. Full article

Bed-separation grouting filling mining is a damage-mitigation mining technology characterized by non-interfering mining and filling operations, low cost, and high efficiency. To recover coal resources from the 3801 working face located beneath a surface gas station in a Shanxi coal mine, this study first analyzed the maximum allowable deformation values for the gas station’s canopy, business hall, and oil storage tanks. Second, the feasibility and safety of bed-separation grouting filling mining at the 3801 working face were investigated using physical similarity modeling and the probability integral method. Finally, a field application of this technology was carried out at the 3801 working face. The results show that: (1) After the successive mining of the 3802, 3803 and 3801 working faces, the No. 17 bed separation was finally preserved above the 3801 working face. It is located in the upper part of the water-conducting fracture zone and has a thick impermeable isolation layer. (2) Physical similarity simulation and numerical simulation (3UDEC) of bed-separation grouting filling mining at the 3801 working face indicate that the underlying strata are effectively compacted after mining, and both overlying strata movement and surface subsidence above the grouting zone are significantly reduced. (3) The probability integral method was adopted to predict surface movement and deformation induced by mining at the 3801 working face (bed-separation grouting filling mining), the 3802 working face (fully mechanized top-coal caving mining) and the 3803 working face (full-seam mining in a single lift). All surface movement and deformation indices satisfy the surface deformation control requirements for the gas station. (4) After completion of the overburden bed-separation grouting filling project at the 3801 working face, the measured surface movement and deformation values during and after mining are all below the allowable deformation limits. No large deformations or cracks occurred in gas station structures including the canopy, business hall and oil tank farm. The protection effect is satisfactory, and the gas station has maintained normal operation throughout the mining period. Full article

Background/Objectives: The use of artificial intelligence (AI) in imaging departments is increasing in Europe. This study assesses the clinical value of an AI fracture algorithm by assessing ease of use, clinicians’ trust, and perceived barriers and benefits of this decision support tool in daily practice across two emergency departments (EDs) in Denmark. Methods: An online survey was distributed over four weeks (June–July 2025) to healthcare professionals interpreting radiographs in the ED at Lillebaelt Hospital. The survey included open-ended, closed-ended, and free-text questions addressing AI use. Additionally, an observational study was conducted, including workflow observations and time tracking of patient progression through the ED. Historical injury conference records from February 2023 to 2025 were reviewed to assess changes in patient management before and after AI implementation. Results: A total of 56 responses were obtained (24 male, 32 female). Most respondents reported a positive attitude toward the algorithm. Ease of use was rated satisfactory by 51 out of 56 participants, and 48 were satisfied with AI as a clinical decision support tool. Overall trust was high, with more than two thirds (n = 38) “agreeing” or “strongly agreeing” that the algorithm reliably detects fractures. However, an asymmetry in clinical trust was observed, whereby clinicians expressed greater confidence in their own assessments when the algorithm indicated the presence of a fracture than when it did not. Value stream analyses showed a delay of 6–23 min between radiograph acquisition and availability of the AI report. No differences were observed in the number of patients with treatment changes before, during, or after full implementation of the algorithm. Conclusions: In our limited study population, the AI fracture detection tool was overall well received by clinicians, although some observations indicate that implementation and workflow integration still require improvement. Larger studies are needed to validate the reported barriers and benefits of the AI fracture detection tool. Full article

Given the severe water hazard in the coal seam roof of the Binchang mining area, existing research methods still primarily rely on traditional approaches such as empirical formula and numerical simulation—resulting in insufficient accuracy and convenience in predicting the height of the water-conducting fracture zone (WCFZ). By comprehensively considering three influencing factors—mining thickness, mining depth, and working face length—a data-driven approach was employed to construct a multiple nonlinear regression prediction model and a Convolutional Neural Network (CNN) prediction model based on 27 sets of measured data. Both models were subsequently applied to the ZF1403 and ZF1405 working faces in the Yadian coal mine. The results indicate that when considering only single factor of mining thickness, the coefficient of determination (R²) value of the multiple nonlinear regression model was 0.64. When considering all influencing factors, R² improved to 0.84. The mean absolute percentage error (MAPE) of multiple nonlinear regression model was 7.52%. The established CNN model achieved a R² of 0.97, a root mean square error (RMSE) of 9.78, and a MAPE of 4.67%. Compared to the Back Propagation Neural Network model, the prediction accuracy of the CNN model was significantly improved. The relative prediction errors of the developed height of WCFZ in the ZF1403 and ZF1405 working faces at Yadian mine were 6.30% and 2.54% for the multiple nonlinear regression model, respectively, and 0.97% and 3.15% for the CNN model, respectively. Both models met practical engineering requirements. This paper can provide reliable technical support for the prediction of water-conducting fracture zone height under mining conditions similar to the Binchang mining area. Full article

Background/Objectives: The development of high-performance biocompatible polymers such as zirconium-reinforced polyether ether ketone (BioHPP^®) has expanded the range of materials available for implant-supported prostheses, traditionally limited to metal alloys and zirconia. Due to its favorable mechanical properties and elastic modulus similar to cortical bone, BioHPP^® has been proposed as a potential alternative in implant prosthodontics. This systematic review aimed to analyze the biomechanical behavior of zirconium-reinforced PEEK and assess its advantages and limitations in implant prosthetic applications. Methods: A systematic review was conducted in accordance with PRISMA 2020 guidelines, including studies published between 2011 and 2025 that evaluated the performance of BioHPP in implant prosthetic applications. Results: The search strategy identified 34 studies that met the inclusion criteria. The included studies evaluated mechanical properties such as fracture resistance, elastic modulus, stress distribution, and peri-implant tissue response. Zirconium-reinforced PEEK demonstrated fracture resistance values reaching up to 1623.31 N and an elastic modulus of approximately 4 GPa, comparable to cortical bone. Several studies also reported favorable stress distribution patterns and reduced mechanical complications when compared with conventional metallic materials. Conclusions: Zirconium-reinforced PEEK exhibits promising biomechanical characteristics for use in implant-supported prostheses, particularly due to its fracture resistance and bone-like elastic modulus. However, the available evidence is predominantly based on in vitro and finite element studies. Long-term clinical trials are required to confirm its clinical performance and establish definitive recommendations for routine use. Full article

Supercritical carbon dioxide (SC-CO₂) fracturing has emerged as an environmentally friendly alternative to conventional water-based hydraulic fracturing; however, its inherently low viscosity restricts proppant-carrying efficiency and reduces fracture conductivity. To address this limitation, this study systematically investigates the rheological behavior and sand-carrying mechanisms of CO₂ dry fracturing fluid under various thermodynamic and compositional conditions. Rheological measurements were conducted to evaluate the effects of thickener concentration, temperature, and pressure on viscosity, while visualized experiments were performed to examine the influence of injection rate, sand ratio, thickener concentration, and temperature on proppant migration and deposition. A numerical model developed in Fluent was further employed to simulate the temporal evolution of proppant transport within the fracture. The results show that higher thickener concentrations and injection rates significantly enhance proppant transport distance and uniformity, whereas elevated temperature and sand ratio promote localized settling. The simulation results agree well with the experimental observations, validating the model’s reliability. This study elucidates the coupled effects of rheology and operating parameters on CO₂ dry fracturing behavior and provides theoretical and experimental guidance for optimizing CO₂-based fracturing fluids in low-permeability reservoirs. Full article