Search Results (185)

Background: Blunt thoracic aortic injury (BTAI) is an uncommon but life-threatening consequence of blunt thoracic trauma. Left-sided hemothorax is frequently identified during initial evaluation and typically prompts early chest drainage. However, when an unrecognized BTAI is present, pleural decompression may precipitate hemodynamic instability. This study aimed to identify early predictors of BTAI requiring thoracic endovascular aortic repair (TEVAR) in patients presenting with left-sided hemothorax. Methods: We conducted a single-center retrospective cohort study including consecutive trauma patients aged ≥ 16 years with radiologically confirmed left-sided hemothorax between 2015 and 2025. Patients were stratified according to the need for TEVAR. Clinical, laboratory, and radiological variables available at emergency department admission were analyzed. Independent predictors of BTAI requiring TEVAR were identified using multivariable logistic regression. Results: Among 146 included patients, 27 (18%) underwent TEVAR for confirmed BTAI. Patients requiring TEVAR were generally younger and more frequently involved in high-energy trauma. Independent predictors of TEVAR included high-energy mechanism (p = 0.048), lower admission hemoglobin (p = 0.007), presence of extra-thoracic fractures (p < 0.001), and a higher number of right-sided rib fractures (p = 0.018). The volume of left-sided hemothorax was not independently associated with BTAI. The model demonstrated strong discriminative ability (AUC = 0.926). Conclusions: In trauma patients with left-sided hemothorax, BTAI requiring TEVAR may occur even in the presence of minimal pleural effusion. Readily available admission parameters may help identify patients who could benefit from a CT angiography-first approach rather than routine early chest drainage, except in cases of immediate life-threatening pleural compromise. Full article

Negative Poisson’s ratio (NPR) bars, as novel materials, exhibit a significant volumetric dilation effect under tension. Compared to conventional reinforcement, NPR bars offer distinct advantages, including high ductility, high strength, and superior corrosion resistance. This study investigates the tensile properties of three types of NPR bars: the bare round bar, spiral ribbed bar, and steel strand. Their bond behavior with concrete was examined through central pull-out tests, considering the influences of bar type, NPR bar diameter, and anchorage length. The analysis focuses on the tensile mechanical properties, characteristics of the bond–slip curves, failure modes, and the development of predictive models for key bond–slip parameters. The results indicate that all three NPR types possess a high elastic modulus and exceptional ductility. The bare round bar achieved an elongation at break of 51.2%, with only minor necking observed at the fracture surface. The bond failure mode is influenced by bar type, NPR bar diameter, and anchorage length: pull-out failure occurred for the bare round bar, spiral ribbed bar with short anchorage length, and small-diameter steel strand, whereas splitting failure was observed for the spiral ribbed bar with long anchorage length. The large-diameter strand exhibited a combined splitting–pull-out failure. Furthermore, the bond–slip curves for the bare round bar and steel strand displayed two distinct peak strengths. The bond strength of the bare round bar increased with longer anchorage length, while it decreased for both the spiral ribbed bar and steel strand. Empirical models developed based on experimental data demonstrate good predictive accuracy for the bond performance of the different bar types. Full article

In shale gas extraction, solid particles such as fracturing proppants cause erosion in production and transmission pipelines. Cyclone desanders are widely used for gas–solid separation, but high-velocity sand-laden fluids frequently induce equipment failure, leakage and safety risks. Therefore, research on erosion and protective measures is essential. This study focuses on the desander at the M shale gas wellhead, where wall thickness was measured at three monitoring points to determine erosion rates. A CFD-based numerical erosion model for the cyclone desander was developed using ANSYS Fluent within the ANSYS Workbench 19.2 environment (ANSYS, Inc., Canonsburg, PA, USA). The model was validated by comparing simulation results with field data, revealing the distribution patterns of the velocity field, pressure field, and erosion rate. The study analyzed the impact of nine factors on desander erosion: inlet aspect ratio, cylinder radius, cone length, dust discharge port diameter, exhaust port diameter, particle size, particle concentration, inlet velocity, and operating pressure, clarifying the erosion variation patterns for each factor. SPSSAU V25.0 (Beijing Qingsi Technology Co., Ltd., Beijing, China) was employed to analyze the significance of these nine factors, identifying six significant influencing factors: inlet aspect ratio, cylinder diameter, dust discharge port diameter, particle size, particle concentration, and inlet velocity. Subsequently, response surface analysis was performed using Design-Expert 13 (Stat-Ease, Inc., Minneapolis, MN, USA) to obtain the relationship between the factors and their impact on maximum erosion, leading to the establishment of a predictive model for the maximum erosion rate. In addition, geometry optimization, local wall thickening, coating protection, material selection, and bionic rib structures were discussed as erosion-mitigation strategies. The optimized geometry reduced the erosion rate at the inlet and dust discharge outlet by 20.4% and 21.8%, respectively, while the bionic rib structure reduced the maximum erosion rate by 58%. Full article

An integrated rebar box connection is proposed for the horizontal joints of fully prefabricated composite walls to simplify joint detailing and reduce on-site wet construction. Experimental tests and numerical analyses were conducted to evaluate the behavior of this connection. The results show that both specimens exhibited shear-dominated failure. The box connection and horizontal joint did not experience obvious fracture or pull-out failure, although local cover spalling, mortar crushing, and connector deformation were observed, suggesting effective force transfer between the upper and lower wall panels under the tested conditions. Compared with the cyclically loaded specimen, the monotonically loaded specimen exhibited higher peak load and larger deformation capacity under monotonic loading, whereas the initial stiffness was similar. The numerical results agree reasonably well with the experimental responses. The parametric finite element analyses indicate that increasing the integrated rebar diameter, the longitudinal reinforcement ratio in the rib columns, the concrete grid strength, and the axial compression ratio improves the load-carrying capacity of the wall, although a higher axial compression ratio reduces ductility. The proposed connection shows promising potential for use in the horizontal joints of fully prefabricated composite walls, and further studies with additional specimens and comparative connection details are warranted. Full article

Background: Rib fractures are a common cause of morbidity in trauma patients. The surgical stabilization of rib fractures (SSRF) has gained increasing attention as a therapeutic option; however, evidence from multiple meta-analyses remains heterogeneous. Methods: We performed an overview of 11 meta-analyses, including a total of 1,117,849 adult patients (narrative umbrella review), published between November 2020 and November 2025 to summarize and critically appraise high-level evidence comparing SSRF with non-operative management (NOM) in adults with traumatic rib fractures. PubMed (MEDLINE) and Embase were searched for eligible meta-analyses. Outcomes of interest included mechanical ventilation duration, pneumonia, ICU and hospital length of stay, mortality, pain, quality of life, and need for tracheostomy. Results: Eleven meta-analyses met the inclusion criteria. Across outcomes, the direction of effect generally favored SSRF in selected patients, particularly with respect to a shorter duration of mechanical ventilation (mean difference up to approximately 4–6 days), reduced pulmonary complications (risk ratio approximately 0.4–0.7), shorter ICU and hospital stay, and improved pain control. However, results varied substantially across studies. A consistent mortality benefit was not observed. Subgroup analyses suggested that the benefits of SSRF were more pronounced in patients with flail chest, severe fracture patterns, and early surgery, whereas findings were less consistent in elderly patients and in patients with less severe injuries. Conclusions: This narrative umbrella review suggests that SSRF is associated with improved short-term outcomes in selected adult patients with traumatic rib fractures but should not be considered a universal standard of care. Careful patient selection, timing of intervention, and multidisciplinary evaluation remain essential. Further high-quality prospective studies are needed to better define optimal indications and management strategies. Full article

Background: Missed fractures on initial imaging assessments remain a clinically significant source of diagnostic errors in orthopedic and trauma care. AI-assisted imaging tools are increasingly integrated into fracture detection workflows. However, their diagnostic benefits and safety vary substantially across anatomical regions, clinical contexts, and levels of reader experience. Purpose: To synthesize the current evidence on the diagnostic impact of AI-assisted fracture detection and to discuss evidence-informed principles for safe and selective clinical deployment. Methods: A structured narrative synthesis of meta-analyses, multi-reader, multi-case observer studies, and real-world implementation investigations was performed. Diagnostic performance patterns were examined across anatomical regions and levels of reader experience. No quantitative pooling or reanalysis of the primary data was performed. The findings were synthesized across anatomical regions, reader-experience groups, and implementation-relevant clinical contexts. Results: Across studies, AI-assisted interpretation was generally associated with moderate gains in sensitivity and lower missed-fracture rates compared with unaided human reading, while largely preserving specificity. The diagnostic benefit was greatest among less-experienced readers in high-volume emergency settings. Performance was strongly anatomy-dependent: consistent and clinically meaningful improvements were observed for hip and appendicular skeleton fractures; intermediate benefits with increased false-positive burden were reported for wrist and rib fractures; and inferior sensitivity relative to expert interpretation was documented for cervical and vertebral spine injuries. Conclusions: AI-assisted fracture detection improves diagnostic safety when implemented as a structured second-reader tool; however, its effectiveness depends heavily on anatomy. Available evidence supports selective, risk-stratified deployment, guided by anatomy-specific risk considerations and supervised clinical use, rather than indiscriminate or autonomous use, to maximize benefits and minimize patient safety risks in orthopedic and trauma imaging. Full article

The scientific literature increasingly supports the use of computational models to predict fracture across a wide range of applications, which, when calibrated with experimental data, can yield highly consistent results. Although the extended finite element method (XFEM) is widely used in commercial packages, phase field (PF) methods have emerged as a robust alternative. In this study, a cohesive zone model (CZM) was implemented using both approaches (a PF model with an implicit damage initiation criterion and a standard commercial XFEM solver with an explicit damage initiation criterion) to analyze their robustness and computational efficiency. First, a standardized fracture test of a compact tension (CT) specimen was simulated and compared with experimental data to validate both methods, achieving accurate predictions under plane strain conditions with a dominant mode I fracture behavior. Subsequently, the application of both fracture models was extended to flexible thoracic prostheses across two distinct chest wall reconstruction scenarios: a single-rib unilateral model and a multi-rib bilateral configuration. An extreme-case compressive displacement was assessed to identify critical regions susceptible to fracture initiation and to evaluate the structural limits of the proposed designs. The results showed that the PF approach required a higher computational time, but exhibited more stable convergence. In contrast, the XFEM-based solver required careful mesh calibration to ensure convergence under complex conditions. These results highlight the potential of the PF approach as a practical tool for identifying and improving critical regions of implants, overcoming the limitations of commercial XFEM implementations. Full article

The structural optimization and mechanical reliability of novel biodegradable JDBM magnesium alloy rib claws were investigated in this study. Simulation analysis, in vitro bending tests, and a 24-week animal implantation experiment demonstrated the promising application potential of the optimized Gen3 magnesium alloy rib claw. Compared with the pre-optimized Gen1 design, finite element analysis (FEA) confirmed that the Gen3 claw—achieved by increasing the width from 6.0 mm to 8.52 mm and adding 1.65 mm transitional fillets at stress concentration zones—resulted in a 54.15% reduction in the maximum von Mises stress (from 116.91 MPa to 53.59 MPa) and a 54.4% decrease in the equivalent strain. In vitro four-point bending tests (ASTM F382-compliant, 11.7 mm span) showed that the Gen3 magnesium claws exhibited a significantly higher yield load (358 ± 21 N) compared with titanium claws (219 ± 16 N; p < 0.05, independent t-test). A 24-week in vivo evaluation in Bama pigs further confirmed the excellent mechanical reliability of the optimized Gen3 magnesium alloy rib claw, and no fractures were observed throughout the implantation period. Full article

Objectives: The aim of this study was to determine differences in injury types and frequencies between piston-based and band-based automated chest compression devices in patients with non-traumatic out-of-hospital cardiac arrest (OHCA) at a German cardiac arrest center. Methods: This retrospective single-center study assessed resuscitation-related injuries in OHCA patients using protocol-based early whole-body CT scans at hospital admission. CT scans were reviewed independently by two reviewers blinded to the compression device used. Between May 2015 and September 2021, all patients resuscitated from non-traumatic OHCA, treated with a mechanical chest compression device, and showing stable return of spontaneous circulation (ROSC) until CT examination according to the institutional standard operating procedure for all OHCA patients were included. Patients were categorized by compression device type, and group differences were analyzed using the Chi-square test and Mann–Whitney U test. In addition, patient-level incidences of rib fracture types were calculated, and risk ratios with corresponding 95% confidence intervals were used to compare rib fracture patterns between groups. A p-value of <0.05 was considered statistically significant. Results: Among 71 patients, 32 received band-based and 39 piston-based treatment. Both groups were comparable in resuscitation duration, body constitution, and gender ratio, although the band-based group was older. Thoracic injuries predominated, with rib fractures representing the most frequent injury pattern (64/71, 90.1%). The median number of rib fractures per patient was 10 (IQR 8–12) in the band-based group and 9 (IQR 7–12) in the piston-based group. The band-based group had significantly more liver lacerations (5/32, 15.6% vs. 0/39, 0%; p = 0.01) and displaced rib fractures (117 vs. 87; p = 0.046; patient-level RR = 1.43, 95% CI 1.06–1.93). Conclusions: In this observational study of a CT-based cohort of OHCA patients with stable ROSC, the band-based device was associated with significantly higher frequencies of liver lacerations and displaced rib fractures than the piston-based device. These findings should be interpreted as hypothesis-generating and may support further evaluation of device-specific injury profiles in future studies. Full article

This study addresses the limited availability of unified experimental datasets comparing ribbed steel and smooth FRP bars embedded in the same hybrid-fiber high-performance concrete (HPC) matrix under identical conditions. It investigates the mechanical and bond behavior of a triple-fiber HPC combining hooked-end steel (ST), basalt (BA), and polypropylene (PP) fibers and reinforced with steel, GFRP, and CFRP bars of identical diameter and embedment. Under a uniform curing regime, the HFRC reached a compressive strength of approximately 82 MPa and exhibited a high fracture energy G_f approximately 3.7 kJ/m² with a stable post-peak response in a notched-beam test, demonstrating effective multi-scale crack bridging within a dense hybrid fiber network. Pull-out tests on 200 mm embedment revealed distinct interfacial mechanisms: ribbed steel developed a pronounced peak bond stress (τ_max = 13.05 MPa) and the largest bond energy (G_b = 146 N/mm) due to mechanical interlock, whereas smooth GFRP and CFRP showed low τ_max (=1.46 and 0.78 MPa) and smoothly decaying τ–s governed by adhesion–friction with G_b = 3–4 N/mm. A consistent experimental framework enabled direct mechanistic comparison of bond–slip behavior across reinforcement types without confounding matrix or curing variables. Simple constitutive laws calibrated to the experimental τ–s curves (ramp–softening for steel and ramp–plateau or exponential for FRP) captured the stiffness, strength, and energy hierarchy with low error. The main contribution of this study lies in providing a configuration-consistent reference dataset and calibrated bond–slip descriptions for hybrid-fiber HPC members reinforced with both steel and FRP bars. The results highlight the role of the hybrid fiber network in improving crack stability and provide design-oriented parameters for anchorage assessment and nonlinear bond–slip modeling. Although the results are based on a limited experimental program, they establish a mechanistically coherent basis for further optimization of hybrid HPC matrices and development of performance-based anchorage formulations in high-performance structural applications. Full article

Background: Traumatic hemothorax is a common complication of blunt chest trauma and remains associated with significant morbidity and mortality. Although contrast-enhanced computed tomography (CT) is central to diagnosis, the optimal criteria for selecting patients who require invasive management versus conservative treatment remain unclear. This study aimed to evaluate the management strategies and clinical outcomes of traumatic hemothorax and to identify predictors of surgical intervention and postoperative complications. Methods: We conducted a retrospective, single-center cohort study including adult patients admitted to a Level II Emergency Department with hemothorax following blunt chest trauma between January 2019 and December 2024. Primary outcomes were the need for urgent chest drainage or surgery. Secondary outcomes included postoperative complications, length of hospital stay, and intensive care unit admission. Univariable and multivariable regression analyses were performed to identify factors associated with surgical intervention and complications. Results: Seventy-two patients were included (mean age 60.0 ± 20.5 years; 80.6% male). Rib fractures were the most common cause of hemothorax (61.1%). Chest tube placement was required in 70.8% of cases, and 31.9% underwent urgent surgical intervention. Active bleeding on contrast-enhanced CT was identified in 16.7% of patients and was the only independent predictor of urgent surgery (OR 3.85, 95% CI 1.07–13.88; p = 0.039). The initial volume of blood drained after chest tube insertion did not differ between surgically and non-surgically managed patients. Conservative management was successful in 19.4% of cases. Postoperative complications occurred in five patients and were associated with a higher comorbidity burden. Overall mortality was 5.6%. Conclusions: In traumatic hemothorax following blunt chest trauma, active bleeding on contrast-enhanced CT seems to be the strongest predictor of urgent surgical intervention, whereas initial pleural drainage volume alone is not. Conservative management is safe in selected patients, while comorbidities influence postoperative outcomes. Multidisciplinary management and accurate radiological assessment are essential to guide timely and appropriate treatment. Full article

Thick oil shale roofs in the Zichang mining area frequently suffer from delamination and sudden brittle fracture, compromising support stability. Using the 50117 return-air roadway as a case study, this paper integrates microstructural characterization (SEM-EDS/XRD), mechanical testing, theoretical interpretation, and FLAC3D simulation to elucidate the instability mechanism. Results indicate that the preferred orientation of clay minerals along bedding yields a “weak friction” signature, facilitating delamination. Simultaneously, the rigid quartz framework enables rapid energy storage, yet constrained bending dissipation triggers instantaneous fracture. This “weak friction-strong cementation” property drives the “delamination-brittle fracture” mechanism. Notably, the roof exhibits low principal stress concentration but extreme sensitivity to deviatoric stress, typifying a “low-stress environment and weak structural damage” behavior. Accordingly, a synergistic control technology featuring “high-prestress normal clamping and dowel shear resistance” was proposed. Field application confirmed its effectiveness in suppressing delamination and reducing rib convergence, thereby ensuring long-term roadway stability. Full article

In side-impact collisions, the occupant in the non-impacted far-side position faces a high risk of death and serious injury. However, current research on injury to far-side occupants remains limited. This study utilized 40 real-world side collision cases to extract dynamic boundary condition parameters of the impacted vehicle through kinematic reconstruction. These parameters were input into a simplified finite element (FE) vehicle model equipped with a human body FE model in the far-side position. Simulation calculations were performed to obtain head and chest injury parameters for the far-side occupant and assess their injury risk. Finally, the study focused on analyzing the effect of vehicle motion boundary conditions on far-side occupant’s injury risk. The assessment based on the head injury criterion HIC₁₅ shows a low head injury risk for the far-side occupant. However, using the BrIC metric, which accounts for head rotational motion, reveals a significant risk of severe traumatic brain injury in some cases. Regarding chest injury, analysis based on the effective plastic strain of ribs indicated a low risk of rib fractures. However, results from the chest viscosity criterion (VC) and internal organ strain analysis suggested a high risk of soft tissue injury in the chest. This computational investigation, leveraging biofidelic human models, underscores that the human body’s response to complex, multi-directional impacts is not fully captured by traditional metrics. This study concludes that addressing the protection of the far-side occupant is essential in side-impact safety design, with particular emphasis on the unique injury risks posed by vehicle rotational motion, potentially inspiring biomimetic safety systems that better adapt to these complex loading conditions. Full article

This study addresses the major engineering challenges of leaving roadways along the goaf in shallow-buried coal seam tunnels through water-bearing soft rock. It focuses on three core issues: the mechanism of rock mass softening upon water exposure, large-deformation control, and directional pressure relief technology. By integrating laboratory testing, theoretical analysis, numerical simulation, and field testing methods, the evolution of macro- and micro-mechanical properties of rock under water–rock interaction can be studied. The research developed constant-resistance large-deformation rock bolts with “yielding within resistance and resisting within yielding” characteristics, revealed the mechanism of directional fracturing through shaped charge blasting, and proposed a synergistic control technology for along-the-goal rib retention: “shaped charge blasting for roof fracturing and pressure relief + reinforced rib support + debris retention devices.” Research findings indicate: increased sandstone water content triggers dissolution of calcareous cement and expansion of clay minerals, leading to rock strength degradation and accelerated deformation, yet the failure mode remains uniaxial shear failure. The developed constant-resistance large-deformation anchor core device maintains a stable working resistance of approximately 350 kN within a 396–405 mm tensile deformation range, significantly enhancing the support system’s crack-resistant capacity under pressure. The focused jet directs cracks to penetrate along predetermined paths, forming planar damage zones and effectively suppressing vertical damage to the surrounding rock. Based on field monitoring, the tunnel was divided into advance support zones, temporary support zones, and stable tunnel sections, enabling a differentiated support scheme. The engineering application achieved stable tunnel retention and safe reuse. This study provides key theoretical foundations and technical approaches for controlling rock mass stability in similar tunnel conditions. Full article

Symmetry plays a fundamental role in the evolution of mining-induced stress fields and the deformation behavior of roadway surrounding rock. To improve control of roadway deformation under strong mining-induced disturbance, this study takes the 12 Upper 301 face at Buertai Coal Mine and investigates the deformation mechanism and corresponding control methods. Based on an analysis of in situ monitoring data, the key stratum responsible for energy accumulation in the overlying strata was identified. Based on the inherent symmetry of the longwall mining layout, a symmetric predictive model of overburden key-stratum abutment pressure is established, which reveals the spatially symmetric distribution characteristics of the mining-induced stress field. The accuracy of the theoretical model was further verified through a large-scale geomechanical similarity model test, which reproduced the fracture trajectory and stress evolution law of the overburden key strata. To mitigate strong mining pressure, a targeted hydraulic fracturing control technique aimed at specific overburden horizons was proposed and verified through field testing and application. Field monitoring results indicate that roof-to-floor convergence peaked at 235 mm, and rib convergence peaked at 115 mm. Compared with sections without hydraulic fracturing control, the surrounding rock deformation was reduced by 62.3% and 69.7%, respectively, demonstrating a significant pressure relief effect. This approach effectively ensured the roadway stability and enabled safe mining operations. Full article