Search Results (13,813)

Background: Response to neoadjuvant chemoradiotherapy (CRT) in locally advanced rectal cancer (LARC) varies considerably, and oxidative stress may modulate radiosensitivity. This study evaluated ischemia-modified albumin (IMA) and thiol–disulfide homeostasis as potential biochemical predictors of pathological tumor regression. Methods: A prospective observational cohort study was conducted to assess pre- and post-treatment oxidative stress biomarkers in patients with LARC receiving capecitabine-based long-course CRT. Serum IMA, native thiol, total thiol, and disulfide levels were quantified spectrophotometrically. Pathologic regression was graded according to the Modified Ryan system as good (TRG 0–1) or poor (TRG 2–3). Receiver operating characteristic (ROC) analyses, Firth-penalized logistic regression, and internal validation using cross-validation, calibration, and decision-curve analyses were performed. Results: Of 38 screened patients, 31 met eligibility criteria and completed CRT, alongside 31 matched healthy controls. Compared with controls, patients had higher baseline disulfide (15.7 ± 5.2 vs. 11.9 ± 3.1 µmol/L; p = 0.012) and IMA levels (0.886 ± 0.062 vs. 0.798 ± 0.048 ABSU; p = 0.006). Poor responders exhibited higher pre-treatment IMA (0.927 ± 0.045 vs. 0.842 ± 0.050 ABSU; p = 0.020) and disulfide levels (18.4 ± 5.2 vs. 13.0 ± 3.8 µmol/L; p = 0.012). Pre-treatment IMA demonstrated the highest predictive accuracy for poor tumor regression (AUC = 0.872; 95% CI 0.751–0.993). In multivariable Firth-penalized logistic regression, elevated baseline IMA was independently associated with poor pathological response (OR = 3.63; 95% CI 1.22–16.20; p = 0.043), whereas negative circumferential resection margin (CRM) status was independently associated with favorable regression (OR = 0.21; 95% CI 0.02–0.71; p = 0.003). The internally validated model demonstrated excellent discrimination (AUC = 0.948; 95% CI 0.866–0.966) and good calibration. Conclusions: Baseline IMA and CRM status were independently associated with pathological response after CRT in LARC. These findings suggest that oxidative-stress biomarkers may have potential value for response stratification; however, the results should be considered exploratory and require external validation in larger independent cohorts before clinical application. Full article

Shallow-buried coal seams in western China are commonly overlain by deeply incised gully terrain, where mining is often accompanied by coal-wall spalling and abnormal increases in support resistance, which affect safe and efficient production. To investigate overburden failure during shallow-buried coal seam mining under gully terrain and to clarify the support–resistance mechanism, a typical working face was selected as the engineering background. Physical similarity simulation, 3DEC numerical simulation, and theoretical analysis were used to analyze overburden failure characteristics and the coupled evolution of the stress, displacement, and fracture fields. Mechanical models of key-stratum fracture and a support–resistance estimation model were established to reveal the influence of overburden-thickness variation on key-stratum fracture and support resistance. The results show that overburden failure in gully areas exhibits pronounced stage-dependent and asymmetric characteristics. In the similarity simulation, the initial fracture intervals of the key stratum in the downhill section were 32 m and 36 m, indicating an asymmetric fracture pattern with a shorter span on the left side and a longer span on the right side. In the uphill section, the periodic fracture interval of the key stratum decreased from 30 m to 24 m as the overburden thickness increased. During overburden failure in gully areas, the three fields exhibited a coupled relationship: stress concentration at the working face caused overburden failure and subsidence, which promoted fracture propagation, whereas stress redistribution in the goaf compacted the fractured overburden and promoted fracture closure. The overburden failure characteristics differed significantly between mining stages. During downhill mining, the key stratum behaved as a fixed-ended beam with a relatively large fracture interval, whereas during uphill mining, it formed a cantilever beam, and its fracture interval decreased with increasing overburden thickness. The loading mechanism of support resistance was shown to be jointly controlled by variations in gully overburden thickness and key-stratum fracture. During downhill mining, support loading increased gradually under the support of the fixed-ended beam key stratum. During uphill mining, support loading exhibited periodic abrupt increases under the combined effects of increasing overburden thickness and periodic fracture of the cantilever-beam key stratum. These findings provide a theoretical basis for strata pressure control at working faces in gully areas. Full article

Two bio-based insulating oils (BHOs) with average carbon chain lengths of approximately 18 and 22 were investigated as short- and long-chain BHOs. By constructing an oil-paper composite insulation system, the generation law of characteristic gases in the two systems was studied by partial discharge experiments. Based on the ReaxFF reaction molecular dynamics simulation under electrothermal coupling stress, the cracking path, cracking rate, evolution of oxygen-containing small molecules, and generation path of characteristic gases of cellulose polymer were revealed. Both systems produced H₂, CH₄, C₂H₂, C₂H₄, C₂H₆, CO, and CO₂, with CO₂ dominant and C₂H₆ least abundant. The short-chain BHO generated markedly higher amounts of H₂, CO, C₂H₂, and C₂H₄ than the long-chain BHO; after 15 min, its H₂ and CO concentrations were about 3.4- and 2.1-times those in the long-chain system, respectively. ReaxFF simulations showed that cellulose degradation in the short-chain BHO followed stepwise chain scission and continuous decarbonylation, favoring CO and unsaturated gas precursors. In contrast, cellulose chains disappeared faster in the long-chain BHO, producing more oxygen-containing organic fragments and C₁-C₅ oxygenated molecules and a higher small-molecule conversion ratio. Characteristic gas pathway analysis revealed that all seven gases could be generated from cellulose pyrolysis intermediates, and different oil environments primarily influenced gas generation behavior by altering the evolution pathways of these intermediates. These findings, at the molecular scale, elucidate the impact of BHO environments on the degradation mechanism of cellulose polymers, providing a theoretical basis for the condition assessment and design of environmentally friendly oil-paper insulation systems. Full article

Cancer is still one of the world’s major causes of morbidity and mortality; thus, safer and more efficient treatment approaches are required. The structural variety, multitargeted mechanisms, and generally good safety profiles of plant-derived polyphenols have made them attractive anticancer medicines. Flavonoids (like quercetin), stilbenes (like resveratrol), phenolic acids and curcuminoids (like curcumin) are major classes that have shown strong anticancer action against a variety of cancers, including prostate, colorectal and breast cancers. Through targets including PI3K/Akt, MAPK, NF-κB, and p53 signaling networks, these substances influence important molecular pathways involved in tumor initiation and development, including oxidative stress, inflammation, apoptosis, cell cycle control, angiogenesis and metastasis. The clinical translation of polyphenols is still constrained by poor bioavailability, fast metabolism, low aqueous solubility and inefficient pharmacokinetic characteristics, which lead to insufficient systemic exposure and therapeutic efficacy despite strong preclinical data. Their therapeutic applicability is further complicated by variations in absorption and possible dose-related restrictions. To overcome these limitations, the anticancer efficacy of polyphenols has been enhanced via delivery technologies like polymeric nanoparticles, lipid-based carriers, nanoemulsions and phytosome complexes, which have shown improved stability, increased bioavailability and targeted delivery to tumor tissues. This review provides a comprehensive and integrative analysis of plant-derived polyphenols by linking molecular mechanisms, pharmacokinetic limitations and emerging delivery strategies within a translational framework. By bridging these interconnected domains, this review highlights the potential of polyphenols as viable candidates in next-generation cancer therapeutics and underscores the need for well-designed clinical studies to facilitate their successful integration into oncology practice. Full article

The permeability of coal seams plays a critical role in the efficiency of coalbed methane extraction and gas disaster prevention. Traditional permeability models often overlook the anisotropic and dynamic evolution characteristics of coal under varying stress and gas adsorption conditions. This paper proposes a novel permeability evolution model that integrates the effects of effective stress variation and gas sorption-induced deformation on coal permeability. Starting from the concept of face porosity and utilizing a representative voxel approach, the model incorporates the anisotropy of mechanical parameters and adsorption expansion strain to derive the evolution of permeability in three dimensions. The model is validated against experimental permeability data from two distinct coal samples (Sulcis and Sydney), demonstrating its ability to accurately capture permeability changes under different boundary conditions. Furthermore, the concept of “internal expansion strain coefficient” is introduced to quantify the impact of adsorption-induced matrix deformation on permeability. The model provides a theoretical foundation for predicting gas flow behavior in coal seams under complex in-situ conditions and offers significant insights into the optimization of gas extraction strategies. Full article

Objective: To investigate maternal serum silent information regulator-2 protein 1 (SIRT1) levels in pregnancies complicated by intrahepatic cholestasis of pregnancy (ICP) and evaluate their diagnostic performance. Methods: This prospective case–control study included 44 pregnant women with ICP and 44 healthy pregnant controls matched according to gestational age at blood sampling and maternal body mass index. Maternal serum SIRT1 concentrations were measured using enzyme-linked immunosorbent assay (ELISA). Clinical, laboratory, and obstetric outcomes were compared between groups. Correlation, receiver operating characteristic (ROC) curve, and exploratory multivariable logistic regression analyses were performed. Results: Maternal serum SIRT1 levels were significantly lower in the ICP group compared with controls [1.06 (1.05) ng/mL vs. 1.54 (1.74) ng/mL, p = 0.005]. ROC analysis demonstrated modest discriminative performance of maternal serum SIRT1 alone for identifying ICP (AUC: 0.674, 95% CI: 0.559–0.788, p = 0.005). A SIRT1 cut-off value of ≤1.28 ng/mL yielded 63.6% sensitivity and 60.5% specificity. In contrast, ALT alone showed excellent discriminative performance (AUC: 0.927, 95% CI: 0.860–0.995, p < 0.001). Combined ROC analyses demonstrated further improvement with the ALT + albumin model (AUC: 0.962, 95% CI: 0.925–0.999), whereas addition of SIRT1 resulted in only a minimal incremental increase in AUC to 0.966 (95% CI: 0.933–0.998). Maternal serum SIRT1 concentrations were not independently associated with ICP after adjustment for laboratory parameters. Conclusions: Although maternal serum SIRT1 levels were significantly reduced in pregnancies complicated by ICP, their diagnostic performance was modest and provided minimal incremental value beyond conventional biochemical markers. Nevertheless, reduced maternal serum SIRT1 concentrations may support the involvement of inflammatory and oxidative stress-related pathways in ICP pathophysiology and warrant further mechanistic investigation. Full article

Studying Bingham flows in permeable media under a periodic magnetic field enhances the understanding of yield-stress fluids for applications like oil recovery and filtration. This study combines non-Newtonian behavior with porous-medium resistance and magnetic variations, facilitating the analysis of complex flow phenomena, including oscillatory yielding and improved flow control in porous structures. The viscous potential theory is employed to streamline the mathematical processes. The utilization of linear governing partial differential equations of motion, along with appropriate nonlinear boundary conditions, yields additional simplifications. The investigation yields a nonlinear Mathieu oscillator that governs the interfacial displacement. A non-perturbative method is used to convert this nonlinear ordinary differential equation into a linear equation. A non-dimensional formulation minimizes the fundamental variables required to characterize the system by establishing a collection of dimensionless physical characteristics. The study analyzes a nonlinear Mathieu oscillator with complex coefficients to explore system dynamics related to elevation. By simplifying the variable coefficients, it enhances the examination of stability and resonance behavior. Despite inherent complexities, the work effectively clarifies fundamental concepts, contributing to a more coherent understanding of the subject. The Hartman number, magnetic field, and magnetic permeability ratio exert a destabilizing effect. Conversely, the Bingham parameter, Weber number, and periodic frequency exert a stabilizing influence. Full article

In lignite open-pit mines, the blasting mining method and large-scale mechanical shovelling processes induce substantial cyclic disturbances in coal seams at the terminal slope during lignite extraction, significantly increasing the risk of slope destabilisation and damage. Consequently, uniaxial cyclic loading and unloading experiments were conducted to evaluate the mechanical properties and energy evolution of lignite. Acoustic emission (AE) characteristics and macroscopic crack evolution of lignite under cyclic loading and unloading conditions were analysed using AE counts and b-values. The energy evolution of lignite was further examined to elucidate the mechanisms of crack propagation and instability failure. The results indicate that initial damage exists within the lignite, and cyclic loading weakens its mechanical properties. Specifically, the irrecoverable damage resulting from the continuous development of internal cracks leads to the continuous deterioration of the mechanical properties of lignite. During the process of damage accumulation, the energy evolution characteristics of the lignite shift from being dominated by plastic energy dissipation to being dominated by elastic energy storage, which triggers higher energy dissipation and release at the cumulative damage stage. Furthermore, as the stress level increases, the cracks in the lignite transition from tensile–shear composite cracks to predominantly tensile cracks. These findings provide critical insights into the mechanisms of instability and failure in open-pit slopes subjected to cyclic loading and unloading, contributing to the advancement of slope stability management in lignite mining operations. Full article

Background and Objectives: Cervicogenic headaches (CGH) are increasingly common among college students and may negatively affect academic performance and sleep quality. This study aimed to identify the self-reported prevalence of cervicogenic-type head and neck pain in a convenience sample of Saudi college students and to examine its associations with electronic device use, physical activity, and sleep quality among college students in Saudi Arabia. Materials and Methods: A cross-sectional study was conducted among 313 college students from various Saudi university colleges using an online self-administered questionnaire. The questionnaire gathered information on sociodemographic characteristics, electronic device usage, neck pain awareness, physical activity levels, and sleep quality. Descriptive statistics were used to summarize the data, and chi-square tests were used to explore associations between potential predictors and the prevalence of self-reported cervicogenic-type head and neck pain consistent with possible CGH. Results: Most participants were female (84.3%) and aged 18–25 years (95.2%). Cervicogenic-type head and neck pain were reported by 65.2% (n = 204/313), while 56.5% experienced moderate to severe stress. A significant association was found with perceived stress (p = 0.002). Prolonged electronic device use (>4 h/day: 77.9%; p < 0.01), lower physical activity (p = 0.056), medication use (p < 0.01), headache exacerbation with inactivity (p = 0.006), and poor sleep quality (95.1% with PSQI > 10; p = 0.044) were significantly associated. Conclusions: These findings highlight associations between excessive electronic device use, low physical activity, and poor sleep quality with self-reported cervicogenic-type head and neck pain among Saudi college students. Future longitudinal studies and randomized controlled trials are needed to determine whether targeting these factors reduces the prevalence of CGH. Full article

Drilling in deep hard formations poses significant challenges for conventional polycrystalline diamond compact (PDC) cutters, which often suffer from low rock-breaking efficiency and premature failure due to severe cutter-face wear, high thermal loads, and stick-slip vibrations. To overcome these limitations, this study proposes a chisel-shaped PDC cutter and systematically investigates its rock-breaking and thermal characteristics. A coupled temperature–displacement finite element model (FEM) of cutter–granite interaction and a single-cutter indentation model were developed based on elastoplastic mechanics and the Drucker–Prager failure criterion. The rock constitutive parameters used in both models were validated through uniaxial compression tests. Using these models, the influences of cutter shape, back rake angle, and depth of cut (DOC) were analyzed. Compared with a conventional cylindrical cutter, the chisel cutter reduces the cutting force by 13.4% and the axial penetration reaction force by 22%. The cutting force of the chisel cutter remains consistently lower across all tested depths. The optimal back rake angle is 20–25°, and the optimal DOC is 1.5 mm. Full-bit simulations further demonstrate that the chisel-cutter bit creates a more concentrated bottomhole stress field, increases the rate of penetration (ROP) by 19.7%, reduces average torque by 11.34%, and produces smoother torque fluctuations, indicating higher drilling stability. Thermal analysis reveals that the chisel cutter exhibits lower and more stable cutter-face temperatures. Both simulation and experimental results confirm that the chisel design reduces the friction contact area between cuttings and the cutter face, thereby lowering temperature accumulation. Field drilling data corroborate the reliability of the conclusions. These findings provide guidance for the design of PDC bits intended for deep hard formations. Full article

This study investigates a 2D fractional order generalized thermoelastic problem in a homogeneous and isotropic thermoelastic hollow sphere. The sphere is exposed to a decaying heat source, and the governing equations are derived using a refined fractional-order Lord–Shulman (LS) model of generalized thermoelasticity. The Laplace transform technique is used to convert time-dependent PDEs into simpler ODEs in the Laplace domain. Its numerical inversion method is used to revert to the time domain. Numerical simulations are carried out to investigate the distributions of temperature, displacement, and stress fields within the hollow sphere. The obtained results reveal that both the fractional-order parameter and the variable thermal conductivity strongly affect the thermoelastic response, particularly the propagation characteristics of thermal waves, stress intensity, and relaxation behavior. In addition, the curvature of the hollow geometry plays an important role in modifying the radial and circumferential stress distributions and their attenuation throughout the medium. Full article

The successful application of extrusion-based 3D-printed geopolymer mortars largely depends on precursor chemistry, activator composition, mixture proportions, and fresh-state behavior, which is highly sensitive to time-dependent structural build-up. This review examines the relationships among mix design, geopolymerization chemistry, rheological properties, and printability requirements for 3D-printed geopolymer mortars. Particular emphasis is placed on the effects of precursor type, alkaline activator characteristics, liquid-to-solid ratio, additives, and fibers on flowability, yield stress, viscosity, extrudability, buildability, shape retention, and interlayer bonding. The review further discusses how geopolymerization kinetics influence the evolution of fresh-state properties, the printable time window, and the transition from extrusion to structural stability. In addition, early-age performance is evaluated in terms of setting behavior, green strength development, and layer-interface integrity. Current challenges, including the lack of standardized test methods, limited comparability among published studies, and the complex coupling between material design and process parameters, are also highlighted. Finally, the review identifies key research gaps and proposes future directions for developing robust, printable, and sustainable geopolymer mortar systems for additive manufacturing in construction. Full article

Satellite-based vegetation monitoring has evolved from mapping vegetation canopy properties at single points in time toward analysing time-resolved dynamics of vegetation traits and process-related variables. Retrieved traits and solar-induced chlorophyll fluorescence (SIF) are inherently defined by sensor-specific spatial resolution, temporal integration, and spectral response. Modifying these characteristics alters the retrieval problem itself: under nonlinear retrievals and heterogeneous landscapes, aggregation and retrieval are generally non-commutative, and error components scale differently with resolution. Consequently, increasing spatial, spectral, or temporal detail does not guarantee improved ecological accuracy; a phenomenon we term the resolution–accuracy paradox. These interacting processes define the effective scale of vegetation products, which may differ from nominal sensor resolution and governs the interpretation of retrieved vegetation traits. When products with differing resolutions or compositing strategies are combined, scale effects can induce systematic artefacts in spatial patterns and derived dynamic indicators that cannot be resolved through improved per-pixel accuracy alone. This review establishes a scale-aware conceptual framework that treats scale as an explicit diagnostic dimension linking observation characteristics, retrieval formulations, trait definitions, and aggregation operators. We analyse how scale interactions influence spatial patterns, temporal dynamics, disturbance signals, and multiresolution data fusion, and derive diagnostic principles, best-practice guidelines, and research priorities for the scale-consistent interpretation of vegetation trait dynamics and SIF-constrained productivity and stress indicators across spatial and temporal scales. Framed in the context of upcoming hyperspectral missions such as CHIME and FLEX, which increase spectral information content, robust interpretation of vegetation products requires scale-consistent analysis and uncertainty-aware processing. For practitioners, this implies that vegetation products should be interpreted, validated, and compared at their effective scale rather than assuming that a finer spatial, spectral, or temporal resolution necessarily yields more reliable ecological information. Full article

Endocrine-disrupting chemicals (EDCs) are a heterogeneous group of exogenous compounds capable of interfering with hormonal homeostasis and endocrine-regulated physiological processes. Their widespread occurrence in food, water, air, consumer products and industrial materials has raised increasing concern regarding their contribution to chronic disease burden. This review synthesizes current evidence on the exposure characteristics, molecular mechanisms, health effects, and prevention strategies related to major EDC classes, including bisphenol A and phthalates, dioxins and polychlorinated biphenyls, per- and polyfluoroalkyl substances, pesticides, and brominated flame retardants. Evidence indicates that EDCs may act through receptor-mediated signaling, altered hormone synthesis and metabolism, oxidative stress, mitochondrial dysfunction, immune modulation, and epigenetic mechanisms, with effects that may vary according to dose, timing, sex, age, and developmental susceptibility. Reported health outcomes include metabolic and cardiovascular disorders, reproductive dysfunction, hormone-dependent cancers, thyroid disruption, immune dysregulation, and adverse developmental effects. Although complete avoidance is unrealistic, exposure reduction and risk mitigation can be achieved through coordinated individual, clinical, environmental, and regulatory interventions. A life-course approach is essential to limit the health burden associated with endocrine disruption. Full article

We examined the novel vegetative assemblage trajectory of a woodlot within a 235-acre urban brownfield. As our previous work documented the stochastic trajectory of the site’s vegetative guild since 1969 and demonstrated the strong influence of soil metals on forest development, we questioned whether the combined effect of soil stress and the increase in pulse event occurrence and intensity had altered the site’s vegetative assemblage trajectory. Using orthomosaic images, digital elevation mapping, and normalized data vegetation indices, our research assesses shifts in forest productivity and structural changes. These ecological characteristics are then compared to the long-term effects of the site’s total soil metal load and the impact of two pulse events. The decrease in the relationship between soil metal load and canopy productivity was 38% over the course of the study. Canopy surface area and volume increased between 2003 and 2011, then decreased between 2011 and 2014 (volume change above 2 m of 3.14%) due to the pulse events, and then recovered and increased by 2023 (volume change above 2 m of 47.9%). The observed decline in the NDVI–TML association suggests that the apparent influence of the abiotic filter imposed by the soil metals has decreased over time. Full article