Search Results (6,506)

With the development of polar regions and the deepening utilization of cold region resources, a large number of infrastructure projects are continuously being carried out. The freezing temperature of unsaturated soil is a critical factor governing the freezing depth and stability of foundations in cold regions or seasons. Concurrently, the supercooling state of soil significantly influences the assessment of its phase composition and physico-mechanical properties. This study employed physical experiments, theoretical formulas, and numerical simulations to reveal the influencing factors and underlying mechanisms of supercooling characteristics in unsaturated soils under controlled low-rate continuous cooling conditions. The results demonstrate that a reduced temperature gradient between the sample surface and the ambient environment correlates with a lower supercooling limit temperature and an extended supercooling duration. An excessively high cooling rate suppresses the supercooling phenomenon in the sample core due to boundary effects. In contrast, neither the temperature difference nor the external cooling rate exhibit a negligible influence on the freezing temperature. Analysis of the temperature–time curves reveals that the freezing process of silty clay is more stable, exhibiting fewer stepwise temperature declines during the phase change plateau, whereas mudstone shows heightened sensitivity to variations in the thermal gradient. Compared to conventional thermocouple measurements, the proposed methodology achieves an optimal balance between temporal efficiency and measurement accuracy. It not only enhances experimental controllability and data reliability, but also provides more scientific theoretical support and technical pathways for predicting freezing depth, designing foundation thermal systems, and preventing frozen ground disasters in cold region engineering. Full article

The Cairo Monorail System presents significant geotechnical challenges due to its integrated structural configuration and its alignment across heterogeneous soil conditions, including collapsible and swelling soils. This study investigates the foundation performance of the monorail through a combination of advanced site investigations, full-scale pile load testing under dry and wetted conditions, and finite-element modeling incorporating soil–structure interaction. Field load tests on large-diameter bored piles founded in collapsible soils demonstrated a pronounced increase in settlement and a reduction in stiffness following wetting, confirming the sensitivity of pile behavior to moisture variations. Three-dimensional numerical analyses of the integrated monorail system showed that differential settlements between adjacent columns are generally limited to less than 9 mm under serviceability loading conditions, satisfying passenger comfort requirements. Long-term coupled seepage–deformation analyses conducted using PLAXIS indicated that surface water infiltration into swelling soils may induce time-dependent monopile heave of approximately 10 mm over a 50-year design life, which remains within acceptable serviceability limits. The results demonstrate that detailed geotechnical characterization, combined with appropriate numerical modeling strategies, can effectively control differential deformation and long-term heave in continuous monorail systems, ensuring their operational safety and long-term performance. Full article

This study presents a systematic investigation into the seismic performance of precast concrete shear walls using cold-extruded sleeve connections for reinforcement splicing. Quasi-static cyclic loading tests were conducted on a full-scale precast wall specimen and a cast-in-place reference wall to evaluate the influence of construction joint detailing on structural behavior. The experimental results show that the precast wall exhibited progressive crack propagation, stable energy dissipation, and slightly higher ultimate lateral load and deformation capacity compared to the cast-in-place counterpart. In contrast, the cast-in-place wall experienced abrupt failure due to concrete spalling and out-of-plane splitting, highlighting the critical importance of reinforcement continuity and joint configuration. To further investigate key design parameters, high-fidelity finite element models were developed in ABAQUS. Concrete was modeled using the Concrete Damaged Plasticity model, while steel rebars and sleeves were simulated with a bilinear constitutive law. The numerical simulations, validated against experimental data, achieved good agreement in terms of load-drift response, crack patterns, and stress distributions. A parametric study was conducted by varying the wall aspect ratio, axial compression ratio, and longitudinal reinforcement ratio in the boundary elements. The results indicate that both the aspect ratio and axial compression ratio have significant effects on lateral load capacity and drift capacity, whereas the reinforcement ratio in the boundary elements exerts a relatively minor influence. For walls with low shear-span-to-depth ratios and high axial compression, increasing both longitudinal and horizontal reinforcement leads to noticeable improvements in load-carrying capacity and ductility. These findings confirm the reliability of the cold-extruded sleeve connection system in precast shear wall applications. The study establishes a validated numerical framework for seismic performance prediction and provides practical guidance for optimizing the design of prefabricated walls. This contributes to enhancing structural safety and improving seismic ductility, thereby supporting the broader adoption of precast systems in sustainable construction. Full article

As global aquaculture continues to expand, there is increasing interest in sustainable and non-invasive tools for monitoring fish growth. Nile tilapia (Oreochromis niloticus) is one of the most farmed species worldwide. Its biomass estimation often relies on manual sampling or stereo-camera systems limited by water turbidity. This study establishes a robust relationship between lateral target strength (TS) and the total length (TL) and weight (W) of Nile tilapia using a cost-effective 201 kHz single-beam echosounder. Measurements were conducted with free-swimming fish in a controlled pond environment (TL range, 13–44 cm). The results show a strong linear correlation between acoustic and biometric data. Specifically, the relationship for mean TS was defined as TS_mean = 20.4log(TL) − 68.8 (R² = 0.93) and TS_mean = 6.3log(W) − 55.4 (R² = 0.96), proving the system’s accuracy for biomass estimation. Furthermore, the Method of Fundamental Solutions (MFS) was employed for numerical validation based on X-ray morphometry of the swim bladder. Very good agreement was observed between experimental data and numerical simulations, reinforcing the validity of the acoustic models despite the inherent complexity of biological targets. These findings demonstrate that calibrated single-beam acoustic systems provide a viable, non-intrusive tool for real-time monitoring in aquaculture ponds. Full article

Liver cancer continues to be a predominant cause of cancer-related mortality globally, primarily attributable to late diagnosis and a scarcity of dependable biomarkers for early identification. Raman spectroscopy has emerged as a valuable analytical instrument for liver cancer detection, providing rapid, label-free, and non-destructive molecular profiling of biological specimens. Raman-based methodologies can discern malignant from non-malignant conditions by analyzing small biochemical alterations in biofluids, including blood, urine, and exosomes, as well as in liver tissue, yielding unique spectrum fingerprints. Progress in chemometric analysis, including machine learning models and multivariate statistical methods, has significantly improved the diagnostic precision of Raman spectroscopy, attaining elevated sensitivity and specificity across numerous studies. Furthermore, the integration of complementary techniques, such as surface-enhanced Raman spectroscopy (SERS) and Raman optical activity (ROA) has broadened its prospects for clinical application. This review article elucidates the contemporary applications of Raman spectroscopy in the diagnosis of liver cancer, presents pivotal findings across various sample types, and examines the challenges and future prospects of building Raman-based platforms as dependable diagnostic instruments in oncology. Full article

Background and Aim: New-onset atrial fibrillation (NOAF) is a common condition in critically ill patients, yet the evidence on optimal NOAF management and outcomes is limited. This study evaluates the impact of management strategies on short- and long-term outcomes in patients who develop NOAF during their intensive care unit (ICU) stay. Methods: A retrospective, single-centre study was conducted of all patients with NOAF admitted in a multidisciplinary ICU between 2020 and 2023. The clinical characteristics and outcomes of the patients were collected. The endpoints included the characterisation of management strategies, short-term outcomes during ICU stays (including atrial fibrillation [AF] recurrence), and long-term outcomes after discharge (including AF recurrence and a composite of death or cardiovascular hospitalisation). Results: A total of 160 patients developed NOAF (mean age 69.5 ± 11.8 years; 63% male). Most had cardiovascular comorbidities and high illness severity, with frequent mechanical ventilation (87%) and vasopressor (89%) use. Rhythm-control strategies—predominantly amiodarone—were associated with lower in-hospital AF recurrence (OR 0.28, p = 0.044) and a numerical reduction in post-discharge recurrence. Anticoagulation was initiated in 45% of patients and continued at discharge in 44%, without major bleeding. ICU and in-hospital mortality were 33% and 43%, respectively. During a median follow-up of 10 (range 0–56) months, post-ICU discharge AF recurrence occurred in 34% of patients initially discharged in sinus rhythm. Anticoagulation at discharge was not associated with recurrence, while rhythm control in the ICU and absence of in-hospital recurrence strongly predicted reduced post-discharge recurrence (p < 0.001). Nine patients required readmission, mainly for heart failure or ischaemic stroke. The composite long-term outcome occurred in 24 patients (27%). Conclusions: Post-ICU discharge AF recurrence after NOAF was common. Early rhythm-control strategies were associated with lower in-hospital and post-discharge AF recurrence, and individualised anticoagulation appeared safe in this observational cohort. These findings support proactive post-ICU monitoring and risk-adapted management strategies. Full article

The stabilization of rock mass vibrations in underground excavations presents a critical engineering challenge due to the interplay of viscoelastic dynamics, impulsive shocks from blasting or rock bursts, and time-varying delays induced by wave propagation and sensor–actuator networks. In this paper, an integral sliding mode control scheme is developed for a Kelvin–Voigt type hyperbolic system subject to such impulsive effects and time-varying delays. To preserve sliding surface continuity under impulsive disturbances, the impulse information is explicitly incorporated into the design of the integral sliding function. The resulting sliding mode dynamics, which include discrete state jumps, are analyzed using a piecewise Lyapunov functional combined with inequality techniques; sufficient conditions are derived to guarantee asymptotic stability. Moreover, a sliding mode control law is synthesized to ensure that the system trajectories reach and remain on the sliding manifold from the initial time onward, despite parameter uncertainties and external disturbances. Numerical simulations with parameters reflecting realistic mining scenarios verify the effectiveness of the proposed control strategy, demonstrating its potential for practical rock mass vibration stabilization in geotechnical engineering. Full article

The continuation ratio model is a crucial tool for analyzing ordinal response data. However, its explanatory power diminishes under high-dimensional settings where the number of covariates p is large. To address this, we introduce, for the first time, the smoothly clipped absolute deviation (SCAD) penalty into the forward continuation ratio model framework. We propose a corresponding penalized likelihood estimation method that performs simultaneous variable selection and parameter estimation and provides an efficient algorithm for its implementation. Numerical simulations demonstrate the favorable properties of the SCAD penalty: it precisely identifies significant variables while more aggressively shrinking the coefficients of irrelevant ones to zero, outperforming alternative penalties like Lasso and elastic net in selection accuracy. Finally, we illustrate the practical utility of our method through an empirical application using data from the Chinese General Social Survey (CGSS). Full article

The underground sewage pipeline is one of the lifeline projects of the city. The pipeline temperature is one of the important influencing factors for the safe operation of the underground sewage pipeline. This study is based on the sewage pipeline project on Jianning Road in Nanjing; the sewage pipeline temperature monitoring experiment was conducted first. The optical frequency domain reflectometer (OFDR) technology was used to monitor the sewage pipeline temperature. The numerical simulation method was also incorporated to study the variations in sewage pipeline temperature. The optical fiber monitoring data for the underground sewage pipeline temperature were collected, and the spatiotemporal distribution of the underground sewage pipeline temperature was explored. The results show that the underground sewage pipeline temperature is continuously rising, and the rate of increase is slow. The maximum temperature change is 0.55 °C. The numerical simulation results are consistent with the trend of the measured results. The findings will provide a valuable reference for further research on sewage pipeline temperature. Full article

Genomic surveillance is a cornerstone of pandemic response; it has helped guide public health interventions worldwide. However, North Africa stands between limited surveillance resources and efforts to address the data gap in this strategic geographic region that links sub-Saharan Africa and Europe. In this study, we present the first comprehensive evolutionary investigation of Algerian SARS-CoV-2 genomes, revealing their phylogeny, continuous phylogeography within the country, mutation analysis, and a super-spreading event through haplotype network analysis. We characterized the genetic diversity and unique mutation pattern of 449 Algerian sequences, revealing multiple independent introductions into the country since the first reported case on the 25th of February 2020 followed by numerous local transmissions that facilitated the virus’s rapid propagation. This study highlights both the importance of molecular epidemiology and equitable access to resources in implementing genomic epidemiology and in increasing sequencing efforts to strengthen pandemic preparedness. Full article

As the new energy strategy progresses, desert, Gobi, and wasteland areas have become key areas for photovoltaic (PV) development, inevitably bringing new environmental challenges. Although PV power stations act as obstacles with some wind and sand control effects, aeolian erosion remains a problem, especially in localized areas where erosion intensifies. To address this issue, this study uses the PV power station layout in the semi-arid wind and sand region of Yudaokou, Hebei, as a case study. Using computational fluid dynamics (CFD) numerical simulations, a combined layout of PV panels and sand barriers is proposed. It is first assumed that this combined layout improves wind protection compared to photovoltaic arrays. The impact of different sand barrier configurations on the airflow field is analyzed to explore their role in controlling aeolian erosion. By analyzing the airflow field, areas of intensified and potentially intensified aeolian erosion are identified. Based on this, sand barriers are strategically placed in key protective zones on the windward side of the PV array, and the combined layout of PV panels and sand barriers is optimized to improve aeolian erosion control effectiveness and promote the sustainable development of PV power stations. The results indicate that PV panels significantly reduce wind speed by altering local airflow and flow patterns, with the impact primarily concentrated in the first 3 to 4 rows on the windward side of the PV array. By establishing sand barriers beneath the PV panels on the windward side, aeolian erosion can be effectively reduced, with the effect on the airflow field primarily occurring within the 0–0.3 m height above the ground. Continuously establishing sand barriers up to the third row of PV panels effectively reduces wind speed, with further extension not significantly improving wind protection, indicating that the third row of PV panels serves as the critical point for sand barrier establishment. This configuration provides the ideal layout for achieving effective protection and offers theoretical and practical guidance for improving the layout of combined PV power stations. Comprehensive analysis suggests that the optimized configuration of PV arrays and sand barrier layout effectively controls aeolian erosion, with the Model 3, which places sand barriers up to the third row of PV panels, ensuring efficient resource utilization. This study offers a practical approach to reducing damage from wind and sand by optimizing the layout of sand barriers and PV panels, thereby providing important guidance for the sustainable development of PV power stations in arid areas. Full article

The continuous evolution of SARS-CoV-2 affects its infectivity and ability to evade the immune system. The XBB.1.5 subvariant carries numerous mutations compared to previous Omicron variants and exhibits significant evasion of polyclonal neutralizing antibodies. In this study, the mechanistic effects of mutations in the XBB.1.5 spike protein on structural stability, antigenic markers, and antibody epitopes were analyzed using homology modeling, epitope prediction, protein stability analysis, coarse-grained dynamic simulations, and chain-specific interface mapping. Thirty-eight amino acid substitutions were identified relative to Wuhan-Hu-1, including 22 in the receptor-binding region. The prefusion trimeric fold was conserved, with localized rearrangements in the N-terminal domain, receptor-binding domain, and S1/S2 region. Linear B-cell epitope prediction yielded similar epitope counts and length distributions in wild-type and XBB.1.5, but only moderate residue-level overlap (Jaccard ≈ 0.40–0.62), indicating epitope turnover and alteration of four conserved antigenic determinants. Functional screening suggested that ~45% of substitutions could affect protein function. Chain-specific interface analysis of the A–B protomer interface indicated preserved inter-protomer coupling with modest repacking of the polar/directional contacts. Overall, XBB.1.5 appears to maintain ACE2 engagement while redistributing antibody targets, underscoring the need for updated vaccine formulations and therapeutic antibodies. Full article

Large temperature gradients encountered in aerospace, energy, and microelectronics systems impose stringent requirements on material thermal performance. Functionally graded materials (FGMs), characterized by a continuous variation in composition and properties, offer significant advantages in regulating heat transfer and mitigating thermal stresses. This review provides a systematic summary of recent progress in heat transfer design optimization of FGMs under large temperature gradient conditions. From a methodological perspective, advancements in structural and compositional optimization, topology optimization, and multi-objective optimization are reviewed. Numerical simulation techniques, including conventional finite element and finite volume methods, as well as emerging approaches such as peridynamics, isogeometric analysis, and meshfree methods, are discussed with an emphasis on multiphysics coupling. In addition, representative applications of FGMs in electronic thermal management, aerospace thermal protection, energy systems, and building energy conservation are reviewed. Current challenges, including idealized modeling assumptions, limited coordination among multiple optimization objectives, and insufficient reliability evaluation in complex service environments, are identified. Finally, future research directions are outlined, highlighting intelligent design methods, multiscale modeling, advanced manufacturing technologies, and multifunctional integration. This review seeks to provide a comprehensive reference for both fundamental research and engineering applications of heat transfer optimization in functionally graded materials. Full article

Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) is now the most common liver disease worldwide, with a continuously increasing prevalence. The mechanisms involved in its pathophysiology are numerous and may include metabolic, environmental, and genetic factors. Genome-wide association studies have identified key genetic variants, most notably in PNPLA3, TM6SF2, MBOAT7, GCKR, and HSD17B13. This mini review discusses the mechanisms through which these variants contribute to the disease pathogenesis, an area that remains a rapidly evolving field of research. Beyond improving our understanding of MASLD, the identification of these variants may also aid in the development of targeted pharmacological approaches. We first summarize the major genetic variants associated with MASLD and then present findings from studies exploring how these variants may influence the efficacy of emerging pharmacotherapies. Finally, we examine the therapeutic agents in the field of precision medicine that are currently being tested in clinical trials. These therapeutic opportunities are a promising approach that may provide individualized solutions for this chronic liver disorder that affects a wide range of the population. Full article

Inequitable access to affordable, nutritious food is partly sustained because markdowns on perishable products are often delayed until quality deterioration becomes visible, through which affordability gains are limited and waste is increased. In this study, the extent to which Internet of Things (IoT) real-time quality monitoring enables quality-triggered markdowns that reduce waste while improving food equity is examined. An analytical pricing and markdown model for perishables with quality-sensitive demand is developed, and optimal decisions under IoT-enabled quality observability and under a baseline setting without IoT are compared. Convexity is established for the retailer’s problem, and closed-form solutions are derived for the optimal regular price, markdown timing, and markdown depth. Under continuous quality visibility, earlier markdown initiation within the selling horizon is shown to be optimal while product quality remains acceptable, and a deeper markdown than in the non-IoT setting is shown to be optimal. Through numerical experiments, increased sell-through before products become unsalable is demonstrated, waste reduction is quantified, and an expanded time window is shown in which price-sensitive consumers can purchase acceptable-quality food at a lower price. Overall, improved food equity is supported by proactive, quality-aligned pricing policies without retailer profitability being sacrificed. Full article