Search Results (3,280)

After the original support system in the auxiliary transportation roadway of the northern wing of the Zhaoxian Mine failed, the extent of damage and deformation varied significantly across different sections of the drift. A single support method could not meet the engineering requirements. Therefore, this paper conducted research on the classification of roadway damage and zoning repair. The overall damage characteristics of the roadway are described by three indicators: roadway deformation, development of rock mass fractures, and water seepage conditions. These are further refined into nine secondary indicators. In summary, a rock mass damage combination weighting evaluation model based on the FAHP–entropy weight TOPSIS method is proposed. According to this model, the degree of damage to the roadway is divided into five grades. After analyzing the damage conditions and support requirements at each grade, corresponding zoning repair plans are formulated by adjusting the parameters of bolts, cables, channel steel beams, and grouting materials. At the same time, the reliability of partition repair is verified using FLAC3D 6.0 numerical simulation software. Field monitoring results demonstrated that this approach not only met the support requirements for the roadway but also improved the utilization rate of support materials. This provides valuable guidance for the design of support systems for roadways with similar heterogeneous damage. Full article

Background: Hip fractures are common in the elderly and often require ICU admission post-surgery due to high ASA scores and comorbidities. Length of hospital stay after ICU is a crucial indicator affecting patient recovery, complication rates, and healthcare costs. This study aimed to develop and validate a machine learning-based model to predict the factors associated with extended hospital stay (>7 days from surgery to discharge) in hip fracture patients requiring postoperative ICU care. The findings could help clinicians optimize ICU bed utilization and improve patient management strategies. Methods: In this retrospective single-centre cohort study conducted in a tertiary ICU in Turkey (2017–2024), 366 ICU-admitted hip fracture patients were analysed. Conventional statistical analyses were performed using SPSS 29, including Mann–Whitney U and chi-squared tests. To identify independent predictors associated with extended hospital stay, Least Absolute Shrinkage and Selection Operator (LASSO) regression was applied for variable selection, followed by multivariate binary logistic regression analysis. In addition, machine learning models (binary logistic regression, random forest (RF), extreme gradient boosting (XGBoost) and decision tree (DT)) were trained to predict the likelihood of extended hospital stay, defined as the total number of days from the date of surgery until hospital discharge, including both ICU and subsequent ward stay. Model performance was evaluated using AUROC, F1 score, accuracy, precision, recall, and Brier score. SHAP (SHapley Additive exPlanations) values were used to interpret feature contributions in the XGBoost model. Results: The XGBoost model showed the best performance, except for precision. The XGBoost model gave an AUROC of 0.80, precision of 0.67, recall of 0.92, F1 score of 0.78, accuracy of 0.71 and Brier score of 0.18. According to SHAP analysis, time from fracture to surgery, hypoalbuminaemia and ASA score were the variables that most affected the length of stay of hospitalisation. Conclusions: The developed machine learning model successfully classified hip fracture patients into short and extended hospital stay groups following postoperative intensive care. This classification model has the potential to aid in patient flow management, resource allocation, and clinical decision support. External validation will further strengthen its applicability across different settings. Full article

Background: Postoperative cognitive dysfunction (POCD) is a prevalent complication in elderly patients undergoing hip fracture surgery, often resulting in increased morbidity and prolonged rehabilitation. Biomarkers such as Neuron-Specific Enolase (NSE) and S100B protein have shown potential in detecting cerebral injury, yet their role in predicting long-term cognitive decline remains unclear. This study aimed to evaluate the association between biomarkers serum levels and the incidence of POCD in elderly patients undergoing proximal femur fracture surgery. Methods: A multicentric prospective observational study was conducted from January 2023 to February 2024, including 146 elderly patients with hip fractures treated surgically at ASL Bari and the University Orthopedic Department of Foggia. Biomarker levels of NSE and S100B were measured preoperatively (T0), at three days post-surgery (T1), and at one-year follow-up (T2). Cognitive function was assessed using the Pfeiffer Scale (PS) and the Mini-Mental State Examination (MMSE). Statistical analysis was performed using U Mann–Whitney tests and logistic regression to identify risk factors. Results: At three days post-surgery, 20.5% of patients exhibited POCD, with no significant differences in NSE and S100B levels compared to baseline. However, at one year, of the 96 patients investigated 37.9% of patients showed cognitive decline, with significantly elevated NSE (19.88 ± 4.03 μg/L) and S100B (1.86 ± 0.9 μg/L) compared to non-POCD patients (p = 0.01). Risk factors for long-term POCD included older age (OR: 1.24), diabetes mellitus (OR: 4.41), and lower baseline cognitive function (MMSE and PS scores, OR: 0.25 and 9.81, respectively). Conclusions: The study demonstrates that while early POCD is not associated with significant changes in NSE and S100B levels, their elevation at one-year follow-up suggests a possible correlation with chronic neuroinflammation and persistent neuronal damage. Preoperative cognitive impairment, advanced age, and diabetes mellitus are significant predictors of long-term cognitive decline. Incorporating biomarker evaluation and cognitive screening into perioperative management may enhance patient outcomes following hip fracture surgery. Full article

Background: Pilon fractures are severe distal tibia injuries from high-energy trauma, often involving joint and soft tissue damage. Despite surgical advances, long-term outcomes remain poor. This study compared quality of life and functional limitations after surgical treatment of pilon versus tibial shaft fractures using validated PROMs. Methods: This case–control study was conducted at a Level I Trauma Center. Between 2016 and 2019, 84 patients with lower leg fractures were included: 38 pilon and 46 tibial shaft fractures. Inclusion criteria were AO type 42 or 43 fractures and follow-up of ≥24 months; exclusion criteria were polytrauma (ISS > 15), ASA ≥ 3, and incomplete consent. Outcomes were assessed with SF-12, EQ-5D-5L, and VAS-FA. Data were collected 36–48 months postoperatively. Analyses included t-tests, chi-square tests, linear regression. Results: Patients with pilon fractures had significantly poorer physical quality of life than tibial shaft fractures (SF-12 physical: 39 vs. 42, p < 0.05). Mental quality of life showed no significant difference. EQ-5D-5L scores were lower in the pilon group (70% vs. 79%). VAS-FA indicated higher pain and reduced function (total: 64 vs. 76, p = 0.009). Rehabilitation duration correlated with improved VAS outcomes in pilon fractures (p = 0.008), while physiotherapy reduced pain in tibial shaft fractures (p = 0.030). Conclusions: Pilon fractures substantially impair physical quality of life and long-term function, while mental well-being remains unaffected. PROMs provide insights beyond radiological findings and should be integrated into follow-up. Further multicenter studies are required to validate these results and optimize rehabilitation strategies. Full article

Hydraulic fracturing is currently the main technical means to form complex fracture systems in shale gas development. To explore the influence of fracture dip, fracture length and fracture filling degree on the propagation of hydraulic fractures under complex fracture conditions, this paper establishes a 20 cm × 20 cm two-dimensional numerical model by inserting global cohesive elements and conducting triaxial hydraulic fracturing experiments to verify the model. The results show that the fracture filling degree plays a major role in the fracture pressure and the propagation of hydraulic fractures, while the fracture dip plays a minor role. The experimental results are consistent with the model results in terms of the law, but due to the existence of other natural fractures in the test block, the fracture pressure is smaller than that of this model. This model can provide some theoretical basis and technical support for situations where there are complex natural fractures in hydraulic fracturing. Full article

NASICON-type Li_1+XFe_XTi_2-X(PO₄)₃ (x = 0.1, 0.3, 0.4) solid electrolytes for all-solid-state Li-ion batteries were synthesized using a sol–gel method. This study investigated the impact of substituting Fe³⁺ (0.645 Å), a trivalent cation, for Ti⁴⁺ (0.605 Å) on ionic conductivity. Li_1+XFe_XTi_2-X(PO₄)₃ samples, subjected to various sintering temperatures, were characterized using TG-DTA, XRD with Rietveld refinement, XPS, FE-SEM, and AC impedance to evaluate composition, crystal structure, fracture surface morphology, densification, and ionic conductivity. XRD analysis confirmed the formation of single-crystalline NASICON-type Li_1+XFe_XTi_2-X(PO₄)₃ at all sintering temperatures. However, impurities in the secondary phase emerged owing to the high sintering temperature, above 1000 °C, and increased Fe content. Sintered density increased with the densification of Li_1+XFe_XTi_2-X(PO₄)₃, as evidenced by FE-SEM observations of sharper edges of larger quasi-cubic grains at elevated sintering temperatures. At 1000 °C, with Fe content exceeding 0.4, grain coarsening resulted in additional grain boundaries and internal cracks, thereby reducing the sintered density. Li_1.3Fe_0.3Ti_1.7(PO₄)₃ sintered at 900 °C exhibited the highest density among the other conditions and achieved the maximum total ionic conductivity of 1.51 × 10⁻⁴ S/cm at room temperature, with the lowest activation energy for Li ion transport at 0.37 eV. In contrast, Li_1.4Fe_0.4Ti_1.6(PO₄)₃ sintered at 1000 °C demonstrated reduced ionic conductivity owing to increased complex impedance associated with secondary phases and grain crack formation. Full article

Formation damage sensitivity is a primary constraint on productivity in coalbed methane (CBM) reservoirs. Conventional experimental methods, which often employ crushed or plug coal samples, disrupt the natural fracture network, thereby overestimating matrix damage and underestimating fracture-related damage. In this study, synchronous comparative experiments were conducted using raw coal and briquette coal cores, integrated with scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR) analyses to characterize coal composition and pore structure. This approach elucidates the underlying mechanisms controlling reservoir sensitivity. The main findings are as follows: The dual-sample comparative system reveals substantial deviations in traditional experimental assessments. Due to post-dissolution compaction, briquette coal samples overestimate acid sensitivity while underestimating water sensitivity. Stress sensitivity is primarily attributed to the irreversible compression of natural fractures. Differences in acid sensitivity are governed by structural integrity: mineral dissolution leads to collapse in briquette coal, whereas fractures help maintain stability in raw coal. Raw coal exhibits a lower critical flow rate for velocity sensitivity and undergoes significant water sensitivity damage below 1 MPa. Both sample types show weak alkaline sensitivity, with damage acceleration observed within the pH range of 7 to 10. Full article

The epoxy monomer N,1-bis(4-(2-oxiranemethoxy)phenyl)methylamine (HBAP-EP) was synthesized through the Schiff base reaction and epichlorohydrin method, and the HBAP-EP monomer was cured using p-aminobenzene sulfonamide (SAA). Differential scanning calorimetry (DSC), X-ray diffraction (XRD), and polarizing optical microscopy (POM) demonstrated that the epoxy monomer exhibits reversible liquid crystal properties, and the liquid crystal fraction of the monomer can reach 14.4% after curing at 120 °C. The fracture toughness of the resin cured at 120 °C can reach 0.93 KJ·m⁻², and its thermal conductivity is 0.3229 W·(m·K)⁻¹, both of which are higher than those of ordinary epoxy resin. Full article

Groundwater seepage plays a critical role in the long-term safety of high-level radioactive waste (HLW) disposal, yet its characterization remains challenging due to the complexity of fractured rock media. This study introduces the Double-Layered Seismo-Electric Method (DSEM) for imaging groundwater seepage fields with enhanced sensitivity and spatial resolution. By integrating elastic wave propagation with electrokinetic coupling in a stratified framework, DSEM improves the detection of hydraulic gradients and preferential flow pathways. Application at a representative disposal site demonstrates that the method effectively delineates seepage channels and estimates hydraulic conductivity, providing reliable input parameters for groundwater flow modeling. These results highlight the potential of DSEM as a non-invasive geophysical technique to support safety assessments and long-term monitoring in deep geological disposal of high-level radioactive waste. Full article

A systematic study was conducted on the fatigue performance of Q500qENH weathering steel welded joints under low-temperature conditions of −40 °C in this paper. Low-temperature fatigue tests were conducted on V-groove butt joints and cross-shaped welded joints and S-N curves with a 95% reliability level were obtained. A comparative analysis with the Eurocode 3 reveals that low-temperature conditions lead to a regular increase in the design fatigue strength for both types of welded joints. Fracture surface morphology was examined using scanning electron microscopy, and combined with fracture characteristic analysis, the fatigue fracture mechanisms of welded joints under low-temperature conditions were elucidated. Based on linear elastic fracture mechanics theory, a numerical simulation approach was employed to investigate the fatigue crack propagation behavior of welded joints. The results indicate that introducing an elliptical surface initial crack with a semi-major axis length of 0.4 mm in the model effectively predicts the fatigue life and crack growth patterns of both joint types. A parametric analysis was conducted on key influencing factors, including the initial crack size, initial crack location, and initial crack angle. The results reveal that these factors exert varying degrees of influence on the fatigue life and crack propagation paths of welded joints. Among them, the position of the initial crack along the length direction of the fillet weld has the most significant impact on the fatigue life of cross-shaped welded joints. Full article

The use of ultra-long directional drilling holes for large-scale pre-drainage of gas in coal seams offers advantages such as extensive coverage and high efficiency, but its effectiveness in deep coal seams remains unclear. Focusing on the seepage characteristics of the No. 8 coal seam in the Baode Mining Area of Shanxi Province, experimental tests were conducted to investigate the evolution of dual-scale porosity permeability. The relationship between matrix/fracture permeability and effective stress were built. Utilizing numerical simulations, this study reveals the nonlinear mechanism in which permeability behavior during gas drainage is jointly influenced by pore pressure reduction and matrix shrinkage. Field measurements and simulation results demonstrated that in shallow borehole regions (<1500 m), permeability increased by up to 3.5 times, while in deeper regions (>2000 m), drainage efficiency significantly declined due to limited pressure drop propagation. These findings provide theoretical support for optimizing the layout of ultra-long directional drilling holes, enhancing gas drainage efficiency, and ensuring safe mining operations. Full article

Background/Objectives: Comparison between the 10-year probability of major osteoporotic fracture (MOF) calculated with FRAX (pFRAX) and the actual MOF rate was conducted, and the availability of pFRAX was evaluated with a one-center cohort study. Methods: Eligible patients were followed up for 10 years. Risk factors listed as items in the FRAX, and presence of lifestyle-related diseases (LS-RDs), escalated ability to fall (Fall-ability), cognitive impairment (CI), etc., were evaluated concerning MOF. The 10-year probability and actual MOF rate were compared. Risk factors contributing to the discrepancy between the probability and the actual rate were evaluated after dividing subgroups. Results: The study included 931 patients. Factors that contributed to the significantly higher ratio for incident MOF besides items in the FRAX were LS-RD, Fall-ability, CI, and anti-osteoporotic drug intervention. The higher the number of factors presented, the higher the actual MOF prevalence compared to the probability rise. Presenting LS-RD, Fall-ability, and CI are independent of the items in the FRAX. pFRAX was overestimated in the low-risk groups and underestimated in the high-risk group compared to the actual MOF rate. These phenomena are caused by the lack of consideration of these three comorbidity risks. Conclusions: A discrepancy between pFRAX and the actual MOF rate exists. LS-RD, Fall-ability, and CI should be listed in the items of the FRAX for more concision. Full article

Coal seams, as critical components of open-pit mine slopes, are subjected to both quasi-static and dynamic loading disturbances during mining operations, with their mechanical properties directly influencing the slope stability. Consequently, to clarify the mechanical properties and failure mechanisms of coal seams affected by the strain rate under the static–dynamic loading conditions, the mineral composition and meso-structural characteristics of lignite were analyzed in this study, and uniaxial compression tests with different quasi-static loading rates and dynamic compression tests with different impact velocities were conducted. The results indicate that there is an obvious horizontal bedding structure in lignite, which leads to differences in mechanical response and failure mechanism at different strain rates. Under the quasi-static loading, lignite exhibits significantly lower strain-rate sensitivity than compared to dynamic impact conditions. The Poisson’s ratio difference between the bedding matrix and the lignite will produce interfacial friction, which gradually decreases with the increase in the distance from the interface, thus promoting the transformation of lignite from multi-crack tensile shear mixed fracture to single-crack splitting failure. Under the dynamic impact conditions, low-impact velocities induce stress wave reflection at bedding interfaces due to wave impedance disparity between the matrix and lignite, generating tensile strains that result in bedding-plane delamination failure; at higher velocities, incomplete energy absorption by the rock specimen leads to fragmentation failure of lignite. These findings are of great significance for the stability analysis of open-pit slopes. Full article

The aim of the work was to innovate in the field of biodegradable straws by valorizing waste materials, specifically spent coffee grounds (SCG), in combination with food-grade biopolymers. Biodegradable straws were produced using pork gelatin and three starch types (corn, rice, and potato) via a dipping technique designed to ensure reproducible layer formation and structural stability. The prepared straws were analyzed for their physicochemical, antioxidant, textural, and solubility properties. Antioxidant potential was assessed using multiple assays (FRAP, ABTS, and CUPRAC), along with determinations of total polyphenol and flavonoid contents. Texture analysis was conducted to evaluate hardness, fracturability, and compression in comparison with commercial paper and plastic straws. Biodegradability was examined through solubility tests in distilled and seawater. The addition of SCG markedly enhanced antioxidant capacity and increased polyphenol and flavonoid contents, while starch type influenced mechanical performance, with rice starch-based straws showing the highest hardness values. All straws demonstrated complete dissolution in both distilled and seawater within 24 h, confirming rapid biodegradation. The results highlight the dual advantage of SCG incorporation: improving functional properties through antioxidant enrichment and reinforcing environmental sustainability by valorizing food industry waste. This study demonstrates the potential of SCG-enhanced straws as a scalable and eco-friendly alternative to conventional single-use plastics. Full article

Background: Post-traumatic osteomyelitis (PTO) of the lower extremity is among the most demanding problems in orthoplastic reconstructive surgery. It typically follows open fractures, failed osteosynthesis, or implant infection. Effective management requires coordinated infection control, stable skeletal fixation, and timely vascularized soft-tissue coverage. Methods: We conducted a retrospective case series of 20 consecutive patients with PTO of the lower limb treated between 2021 and 2024 at a tertiary orthoplastic center. All patients underwent radical debridement, culture-directed intravenous antibiotic administration, and soft-tissue reconstruction using local muscle, fasciocutaneous, or free flaps; vascularized bone flaps were used to select nonunion cases. The primary outcomes were flap survival, complications, infection resolution, and limb salvage. Exploratory analyses included descriptive subgroup summaries by flap category. Results: Among 20 patients (15 men, 5 women; mean age 53.6 years), reconstructions included reverse/pedicled sural flaps (n = 9), hemisoleus muscle flaps (n = 7), medial gastrocnemius muscle flaps (n = 2), peroneus brevis muscle flaps (n = 2), and free flaps (n = 6), which comprised anterolateral thigh (ALT), medial femoral condyle (MFC) osteoperiosteal, deep circumflex iliac artery (DCIA) osteocutaneous, and radial forearm free flaps (RFFFs). Single-flap reconstructions were performed in 13 cases, whereas multistage/multiflap strategies were used in 7. Overall flap survival was 90%. Major flap complications comprised partial necrosis in two reverse sural flaps and one complete loss of a reverse sural flap; two patients had minor wound dehiscence. Infection resolved in 18/20 patients (90%; 95% CI ≈ 0.70–0.97). One patient requested below-knee amputation due to persistent nonunion associated with a pathological fracture. At a mean 10-month follow-up, all limb-salvaged patients were ambulatory. Conclusions: Effective reconstruction of PTO is improved by using a patient-specific algorithm that considers the defect location, vascular status, and host comorbidities. Local muscle and fasciocutaneous flaps remain dependable for most defects, with free or vascularized bone flaps reserved for composite or recalcitrant cases. Early referral to high-volume centers, radical debridement, and orthoplastic collaboration are critical for optimizing limb salvage. Our findings should be interpreted in light of the study’s retrospective design and small sample size. Full article