Search Results (536)

Hydrogels used for fracture sealing during heavy-oil thermal recovery are repeatedly exposed to high-temperature steam, dehydration, pressure disturbance, and cooling, conditions that often lead to progressive network deterioration and loss of sealing efficiency. To address this limitation, a thermally triggered self-reinforcing covalent–physical double-network nanocomposite hydrogel was developed by combining a sparse MBAA-crosslinked P(NaAMPS-co-NVP-co-AM) covalent scaffold with a reversible Laponite-mediated physical network. The material response was systematically evaluated through cyclic hydrothermal treatment at 180 °C, while fracture-sealing and resealing performance was examined separately under steam-exposure conditions. Artifact-controlled experiments were further introduced to distinguish genuine cycle-induced reinforcement from dehydration, continued post-curing, and conventional thermal aging. The results show that the NaAMPS/NVP/AM molar ratio of 40/20/40 with 1.00 wt% Laponite provided a suitable balance between precursor processability, hydrothermal stability, and mature network stiffness. After five thermal cycles at 180 °C, the storage modulus of the Lap-DN hydrogel increased from 74.4 to 89.1 kPa, while the compressive stress at 50% strain increased from 0.641 to 0.842 MPa, corresponding to reinforcement ratios of 1.198 and 1.314, respectively. Meanwhile, the mean equivalent pore diameter decreased from 6.2 to 4.8 μm, indicating progressive refinement of the load-bearing network. The hydrogel retained 76.3% of its initial water and 81.6% of its initial volume after five cycles in the reference brine and preserved a cycle-5 modulus retention of 101.3% even at 150,000 mg/L salinity. In fracture-sealing tests, Lap-DN sustained a breakthrough pressure of 3.47 MPa and reduced fracture conductivity by 92.4% in a 1.60 mm fracture. More importantly, the same sealing body maintained a breakthrough pressure of 4.55 MPa after five steam impact–recovery cycles in a 1.20 mm fracture, corresponding to 106.1% of the first-cycle value, while 95.0% of the pre-breakthrough pressure resistance was restored within 30 min of cooling. These results are consistent with a cycle-induced reorganization of the Laponite-mediated physical constraints within the permanent covalent scaffold, although the transient dissociation and reassociation of individual polymer–Laponite junctions were not directly observed. Within this evidence-based interpretation, cyclic thermal perturbation is associated with mechanical reinforcement and repeated fracture resealing rather than acting solely as a damaging factor. This work provides a materials-design strategy for hydrogel sealing systems operating under cyclic steam and high-salinity conditions. Full article

Background/Objectives: Distinguishing active from quiescent Behçet’s disease (BD) is difficult because conventional acute-phase reactants perform inconsistently. C1q/TNF-related proteins (CTRPs) are adiponectin paralogues; several members have been reported to exert opposing immunometabolic actions in experimental systems, although the evidence is uneven across the family and no member has been examined in BD. Methods: In this cross-sectional study, eight CTRPs (CTRP1, CTRP4, CTRP6, CTRP9, CTRP12, CTRP13, CTRP14, CTRP15) were measured in serum using enzyme-linked immunosorbent assay in 30 patients with active BD, 30 with inactive BD and 30 healthy controls. Disease activity was defined by a Behçet’s Disease Current Activity Form (BDCAF) score of ≥2. False discovery rate correction was applied separately to the eight omnibus and eight active-versus-inactive biomarker comparisons. Logistic models were adjusted for age, sex, body mass index and disease duration; a composite index combined the analytes changing in opposite directions. Results: Six analytes differed between active and inactive disease after correction (q = 0.004–0.041): CTRP1, CTRP4, CTRP6 and CTRP14 were higher and CTRP12 and CTRP15 lower in active disease, with five correlating with the BDCAF score in the same directions. Four showed nominally significant associations in the adjusted models (CTRP12, CTRP14, CTRP6 and CTRP15), whereas CTRP1 and CTRP4 did not; adjusted odds ratios per doubling ranged from 0.27 (CTRP12, 95% CI 0.11–0.71) to 2.73 (CTRP14, 1.16–6.44). The composite index achieved an area under the curve of 0.866 (95% CI 0.765–0.944); C-reactive protein alone reached 0.810 (0.682–0.915) and the two combined 0.916 (0.839–0.974). Bootstrap internal validation, in which the selection of components was repeated in each resample, gave an out-of-bag area under the curve of 0.812 (0.649–0.946). The index remained associated with activity after adjustment for C-reactive protein (p = 0.002); adding the index to C-reactive protein did not significantly increase discrimination (ΔAUC +0.106, 95% CI −0.002 to +0.214; DeLong p = 0.055). Conclusions: In this cross-sectional study, active BD was associated with a coordinated bidirectional CTRP pattern that paralleled clinical activity. The composite index remained associated with activity after adjustment for C-reactive protein, but its incremental discrimination over C-reactive protein did not reach statistical significance; longitudinal and external validation are required. Full article

The BRICS economies have expanded rapidly while remaining large contributors to global carbon dioxide emissions, which motivates a closer look at the structural covariates of their carbon trajectories. The growth–emissions nexus is well documented, but fewer studies jointly place material footprint and institutional quality in a distributional panel setting. This study estimates the heterogeneous associations of electoral democracy, political corruption, economic growth, and material footprint with per capita carbon emissions in the five BRICS countries from 1980 to 2022. The baseline estimator is the Method of Moments Quantile Regression (MMQR). The Dynamic Common Correlated Effects (DCCE) estimator is used as a mean-based check for persistence and cross-sectional dependence. Double/Debiased Machine Learning (DML), SHAP, and Quantile Regression Forests (QRF) are used as non-parametric checks of pattern consistency, not as independent causal identification. MMQR estimates show that material footprint is positively associated with emissions across quantiles, with the coefficient rising from 0.3859 at the 10th quantile to 0.6224 at the 90th quantile. Economic growth and electoral democracy are negatively associated with emissions mainly at higher emission quantiles; at the 90th quantile the democracy coefficient is −0.2988. The political corruption index also enters with a negative coefficient at the upper tail (−0.8468 at the 90th quantile). Because higher values of this index denote more, not less, corruption, that sign does not support a simple claim that corruption control reduces emissions, and it is not recovered in DCCE or DML. Dumitrescu–Hurlin tests indicate a unidirectional Granger-predictive link from material footprint to emissions and bidirectional Granger links between the institutional variables and emissions. These results are associations from a small-N panel (N = 5, T = 43). They suggest that resource throughput remains tightly linked to carbon outcomes at the upper tail, while several of the growth and governance associations are specification-dependent. Full article

Discrete symmetries govern the motion and real axis crossings of interference zeros in the meromorphic continuation of a wave field, thereby determining the singular structure of its logarithmic derivatives. We considered two counter-propagating second-order rational pulses that satisfy the one-dimensional massless wave equation exactly. With $q=r\mathrm{e}\mathrm{x}\mathrm{p}\left(i\phi \right)$ denoting the relative complex amplitude, the field admits two antilinear reflection symmetries: real $q$ preserves collision-centered spacetime inversion followed by complex conjugation, whereas $\left|q\right|=1$ preserves fixed time spatial reflection followed by conjugation up to an overall phase. The balanced in-phase state, $q=1$, is the non-degenerate intersection of these symmetry manifolds; $q=-1$ produces global cancellation on the collision slice. For $q=1$, the two interference zero branches lie on the imaginary axis and cross the real axis at $ct=x_0\pm \mathcal{l}$, on opposite sides of the pulse center collision. Away from the symmetry manifolds, the zero trajectories deform continuously, and the associated pairing constraints are lost, while the crossing conditions remain available in closed form. A logarithmic complex action representation yields local momentum, energy, transport ratio, and a derived second-order complex action descriptor without altering the underlying wave dynamics. Near an isolated non-characteristic moving zero, the leading simple pole factors cancel in the transport ratio, whereas the second-order term develops a double pole. The leading real axis response therefore scales as $d_{min}^{-2}$. A reference finite-window fit yields an exponent of $-1.885$ ($\rho =-0.995$), and the fitted exponent approaches $-1.998$ as the fitting interval is narrowed toward the isolated-zero regime. These results provide an exact benchmark linking antilinear symmetry, complex zero-pole geometry, and real axis differential amplification. The second-order quantity $Qc$ is used only as a descriptor generated by the logarithmic representation; it is neither an externally imposed potential nor an additional dynamical term. The loss of reflection symmetry away from the two symmetry manifolds is explicit and parameter-induced, not spontaneous. Full article

Water-decking can buffer and redistribute borehole loading, but the coupled effects of axial charge segmentation, radial decoupling, and peripheral-hole spacing across scales remain insufficiently quantified. A cross-scale three-dimensional multi-material Arbitrary Lagrangian–Eulerian (ALE) framework coupled with the Riedel–Hiermaier–Thoma (RHT) damage model was developed for intact granite and applied at single-hole, double-hole, and full-face scales following specimen-scale calibration and numerical consistency checks. Increasing the segment count from four to six reduced the charge-section peak pressure from 283.0 to 257.0 MPa while increasing the water-section peak from 24.5 to 50.7 MPa. Increasing the radial decoupling coefficient from 1.00 to 1.31 reduced the numerical damage span from 55.6 to 33.7 cm. The spacing–decoupling assessment identified the six-segment configuration with K_d = 1.31 and 65 cm spacing as a condition-specific combination that maintained inter-hole damage connectivity while limiting outward disturbance. In the full-face model, multi-hole stress-wave interaction occurred at approximately 0.48–0.52 ms. The D ≥ 0.19 and D ≥ 0.90 damaged regions occupied 2.154% and 0.348% of the representative section, respectively. These results support a sequential axial–radial–spatial regulation framework linking pressure redistribution and inter-hole interaction to full-face stress and damage evolution, providing a basis for smooth-blasting parameter selection under the investigated intact-granite conditions. Full article

Artificial intelligence (AI) is expanding opportunities for adaptive and personalised learning that responds to learners’ abilities, interests, and educational needs. However, formal gifted education programmes may still offer limited opportunities for individualised learning pathways. In this study, gifted education programmes refer to formal provision for identified gifted students that supports differentiated depth, complexity, pace, challenge, enrichment, and talent development. This study proposes an AI-Supported Double-Helix Framework for Personalised Learning in Gifted Education and examines preliminary empirical support for its hypothesised relationships. The framework integrates the Unified Theory of Acceptance and Use of Technology (UTAUT), AI-Supported Adaptive Learning (ASAL), Personalised Learning Experience (PLE), and curriculum integration. Using a quantitative cross-sectional design, PLS-SEM was applied to data from 437 gifted secondary school students. The measurement model demonstrated satisfactory reliability, convergent validity, discriminant validity, and measurement invariance. Performance Expectancy showed the strongest positive association with ASAL, which was positively associated with PLE. PLE was positively associated with perceived Double-Helix Framework Implementation (DHFI), which was subsequently associated with perceived Learning Effectiveness, Talent Development, and Future Readiness. A secondary multi-group analysis indicated that most structural relationships were comparable across gender groups. The study extends UTAUT by linking technology adoption factors with AI-supported adaptation, personalised learning, curriculum integration, and perceived developmental outcomes. It also situates these processes within the context of Education 4.0 through adaptive, data-informed, and future-oriented learning. However, the cross-sectional self-report design provides preliminary empirical support only for statistical relationships among the measured constructs. It does not establish the framework’s educational effectiveness or causal effects on learning. Longitudinal, experimental, behavioural, and performance-based studies are needed to evaluate its educational effectiveness and practical implementation. Full article

In order to improve antibacterial and antioxidant performances, phytic acid (PA) was incorporated into soy protein isolate (SPI) film crosslinked with tara tannins (TTs) and dialdehyde cellulose nanofibers (DACNFs). The resulting PDTSPI (PA/DACNF/TT/SPI) film exhibited enhanced physical and UV-Vis shielding and antioxidant properties. At 15% PA content, the tensile strength (TS) reached 5.17 MPa and the elongation at break (EB) increased to 101.15%, showing the comprehensive mechanical performance. After the addition of PA, the composite films displayed negligible light transmittance at wavelengths under 460 nm, with visible light transmittance reduced to less than 40%. And the DPPH radical scavenging rate increased to 49.2%, demonstrating strengthened antioxidant activity of PDTSPI films. Notably, increasing PA content led to improved antibacterial effects against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), with the inhibition rate of PDTSPI-12 and PDTSPI-15 films for S. aureus achieving 100%. The peroxide value (POV) of beef tallow and total viable count (TVC) of chicken packaged with PDTSPI-15 were only 0.007 g/100 g and 2.17Log CFU/g, respectively—both significantly lower than those packaged with pure SPI film, which demonstrates the potential of PDTSPI film for packaging oily foods and meat products. Full article

Steel-framed modular structures, assembled by stacking modules, show distinct lateral behavior. However, the role of steel plate shear walls (SPSWs) in such structures is rarely studied. This study investigates their influence on the lateral behavior of steel-framed modular structures. Two six-story modular structures are designed: one without SPSWs while the other one with SPSWs. The base shear, failure process, and resisting mechanism of modular structures are studied by pushover analyses. Parametric studies address effects of plate thickness, bolt number, and cross-section of horizontal inter-module links. Contributions of SPSWs and concrete shear walls are compared. For the first time, three distinct resisting mechanisms—individual resisting unit, double-column system, and double-beam system—are identified and systematically explained in the context of SPSWs-enhanced modular structures. A novel tension-tie strip model is developed to quantify the contribution of SPSWs to lateral resistance. Results demonstrate that SPSWs work as tension-tie strips, significantly increasing the stiffness and resisting capacity of modular structures by three to five times depending on the loading direction. The resisting capacity grows with plate thickness. Insufficient bolts or link cross-section can lead to premature failure. Compared to concrete shear walls, SPSWs offer better integrity and drift control under extreme seismic loads. A design scheme is proposed to estimate the increased resistance due to SPSWs with good accuracy and efficiency, offering a practical tool for structural engineers to enhance lateral behavior. The findings provide new insights into the seismic design of modular buildings and establish a foundation for performance-based design of SPSW-reinforced modular structures. Full article

The influence of amino-functionalized double-walled carbon nanotubes (DWCNTNH₂) on the curing behavior and multifunctional properties of an epoxy resin was systematically investigated. Isothermal FTIR analysis, interpreted using Kamal’s autocatalytic model and model-free isoconversional DSC analysis, showed that the presence of amino-functionalized nanotubes accelerates the initial epoxy curing reaction, increasing the primary reaction rate constant, reducing the activation energy, and confirming the catalytic role of the nanotube surface amino groups. Thermal–mechanical analysis indicated the formation of an interphase characterized by locally reduced crosslink density resulting from reactions between the functionalized nanotubes and the epoxy precursor. This interphase slightly lowers the glass transition temperature and the onset of thermal degradation without significantly affecting the overall thermomechanical performance. The incorporation of the filler also produces a remarkable increase in electrical conductivity, with an electrical percolation threshold between 0.1 and 0.3 wt%. Conversely, moisture diffusion and equilibrium water uptake remain essentially unchanged, demonstrating that the low nanotube content does not significantly alter the diffusion pathways or the polarity of the crosslinked network. Full article

It is known that the controlled release of anticancer drugs with low molecular weight from drug delivery systems (DDSs) based on polysaccharides such as chitosan (CS) still encounter certain difficulties because of the high hydrophilicity of the carrier. The release rate is very fast, with a burst release that is usually obvious. Therefore, finding novel systems to carry and release low molecular weight drugs such as 5-fluorouracil (5-FU) is still of interest. The impact of chitosan (CS) characteristics (deacetylation degree and molar mass), and concentration as well as of the strategy employed to fabricate porous nanocomposites CS–laponite (LAP), on the physicochemical properties of CS-LAP sponges was first investigated in the paper. Information about the incorporation of LAP within the CS-LAP nanocomposites was obtained by EDX and FTIR spectroscopy. The influence of the fabrication conditions on the physical cross-linking was evidenced first by the swelling of the composite sponges at equilibrium in distilled water, with lower values of the swelling ratio found for the composites prepared with one freeze-drying (1FD) step, than of those prepared with 2FD steps. The elastic modulus ranged between 6 and 21 kPa for CS-LAP composites prepared with 1FD, and between 2 and 10 kPa for the nanocomposites prepared with 2FD steps. The physicochemical properties of CS-LAP nanocomposite sponges were correlated with their behavior in the loading and in vitro release of 5-FU as a function of pH. It was found that the CS-LAP composites with the highest swelling ratio exhibited the fastest release of 5-FU in simulated gastric fluid (pH 2.0), with the cumulative release in the range of 85–100%, in about 60 min, at 37 °C. The CS-LAP composites with the lowest swelling ratio, displayed the slowest release rate of drug. The drug release from the double component composites was accompanied by the carrier dissolution/disintegration. To retard the release of 5-FU in the gastric environment, the drug was sealed in the porous CS-LAP nanocomposites by simple complexation of the free positive charges of CS with carboxymethylcellulose as polyanion. These systems kept their integrity at pH 2.0, pH 6.8 and phosphate buffer with pH 7.4, and released 5-FU in a controlled manner, making them suitable systems for delivery of 5-FU in both the stomach and small intestine. Full article

Early parental loss may increase depression risk among orphaned university students, yet evidence from low- and middle-income countries such as Thailand remains limited. This cross-sectional study examined depressive symptoms and their associations with attachment insecurity, resilience, inner strength, and perceived social support among 226 Thai university students aged ≥20 years who had lost one or both biological parents before age 18. Participants completed validated Thai versions of the Outcome Inventory–Depression subscale, the Experiences of Close Relationships–Revised 10-item version, the 9-item Resilience Inventory, the Inner Strength-Based Inventory, and the revised Thai Multidimensional Scale of Perceived Social Support. Multiple linear regression identified factors associated with depressive symptoms. The mean depression score was 6.62, with no significant difference between single and double orphans. Attachment anxiety (β = 0.176, p = 0.002) was significantly and positively associated with depressive symptoms, whereas resilience (β = −0.322, p < 0.001), inner strength (β = −0.192, p < 0.003), and perceived social support (β = −0.156, p = 0.022) were significantly and negatively associated with depression. In contrast, attachment avoidance (β = 0.110, p = 0.068) did not reach statistical significance. Among orphaned students, depressive symptoms were more closely linked to psychosocial factors than to the specific type of parental loss (single vs. double orphanhood). Full article

Wearable rehabilitation monitoring requires soft strain sensors with mechanical robustness, stable electromechanical responses, and intelligent motion recognition capability. Here, we report a poly(vinyl alcohol)/polyacrylamide (PVA/PAM) double−network hydrogel strain sensor for rehabilitation−oriented wearable monitoring. The hydrogel was prepared by ultraviolet ray (UV)−initiated acrylamide polymerization followed by freeze−thaw−induced PVA crystallization, forming a covalent PAM network interpenetrated with a physically crosslinked PVA network. The resulting hydrogel possessed a compact porous structure, improved stretchability, and stable deformation recovery. The optimized sensor exhibited a tensile strength of approximately 0.52 MPa, an elongation at break of approximately 480%, a response time of 0.12 s, and a recovery time of 0.17 s. It generated repeatable resistance signals under cyclic strain, finger bending, wrist motion, and grip training. Furthermore, the sensor enabled morse−code information transmission and support vector machine (SVM)−based recognition of rehabilitation−related hand states, including straight, bend, and clench. This work provides a soft hydrogel sensing platform for real−time rehabilitation−oriented hand motion, while morse−code encoding provides auxiliary assistance and an emergency communication function. Full article

Peste des petits ruminants virus (PPRV) causes a highly fatal disease that severely impacts small ruminant production and global food security. This study aimed to develop a rapid, user-friendly colloidal gold immunochromatographic test strip for detecting PPRV-specific antibodies using a double-antigen sandwich format. Bioinformatic analysis using DNASTAR Protean was performed to predict candidate antigenic regions in the PPRV H and N proteins. Three predicted candidate regions from each protein were selected and incorporated into the design of the recombinant fusion antigen PPRV-H₃N₃EP. The recombinant antigen was expressed in E. coli, purified, and refolded to obtain a final concentration of 8.52 mg/mL. The strip was assembled with colloidal gold-labeled fusion protein as the detection probe and unlabeled protein coated on the test line, plus an independent mouse IgG/goat anti-mouse IgG control system. Performance evaluation showed that the results were readable within 10–15 min. The strip showed satisfactory analytical sensitivity and cross-reactivity performance, consistent qualitative results in within-batch repeatability testing, and preliminary short-term storage stability. In a comparative evaluation using sheep serum samples and a commercial competitive enzyme-linked immunosorbent assay (ELISA) kit, the overall agreement reached 97.9%. Collectively, the constructed PPRV-H₃N₃EP antigen enabled a simple, rapid, and reliable strip assay suitable for field detection of PPRV antibodies and post-vaccination monitoring, while also providing a methodological reference for developing antibody tests for other pathogens. Full article

The growing use of blockchain in e-commerce has produced hybrid environments in which private enterprise ledgers and public blockchain networks operate side by side. Consequently, efficient and secure interoperability between these networks has become increasingly important. This study presents a cross-chain interoperability framework that links a permissioned Hyperledger Fabric network with a public Ethereum network. The framework provides attestations of selected business events rather than moving assets. An interoperability smart contract on Fabric emits cross-chain events; an off-chain validator enforces uniqueness and replay protection; and a public verification contract on Ethereum records an immutable, publicly verifiable attestation of each event. The framework uses a two-of-three validator threshold to attest events, so safety holds as long as no more than one of the three validators is compromised. The prototype was evaluated by processing 21,000 events across sequential, concurrent, and peak-load workloads. On the local network, message validation averaged approximately 12 ms per event, and the interoperability layer added less than 200 ms of overhead per attestation. Sustained throughput ranged from 13.2 to 14.2 attestations per second, while the validator used approximately 16% mean CPU and less than 194 MiB of memory, with no sustained memory growth during the full experiment. On the Ethereum Sepolia public testnet, 55 transactions were confirmed with a 100% success rate and a mean confirmation time of 10,676.62 ms. Gas consumption stayed stable at about 51,743 gas per verification on the local network and about 189,092 gas on Sepolia, and the mean public testnet transaction cost was 0.000692 Sepolia ETH. Five adversarial tests were conducted, covering replay, forgery, malicious relayers, concurrent replay, and denial-of-service attacks. All five tests passed, including the rejection of 500 concurrent replay attempts with zero double registrations. The results show that the framework provides efficient, verifiable, and replay-resistant cross-chain interoperability suited to hybrid e-commerce ledgers. Full article

Reliability assessment in complex technical systems often involves capturing the interdependency between multiple subsystems and the gradual loss of their functional effectiveness. This challenge becomes particularly critical in the context of Unmanned Aerial Vehicles (UAVs), where sustained operational capability is essential for the safe execution of autonomous missions. This work presents a state-based methodology to estimate the future mission capability of UAVs subject to progressive component degradation. To generate a representative dataset, around 600 simulated flight missions for each of the 70 UAV fleet members are conducted, distinguished by randomly varying degradation profiles across multiple actuators. A hidden semi-Markov model (HSMM) is trained on this data to characterize the progressive reduction in system performance over time. To improve model tractability and generalization, raw flight data is first reduced to a concise set of performance-related parameters, from which critical sensor signals, such as roll, pitch, yaw, horizontal and vertical airspeeds, and current consumption, are estimated. The approach is evaluated in comparison to Decision Tree (DT) and XGBoost (XGB) models in a 5-fold cross-validation analysis. It enables the identification of system-wide dependencies between degradation patterns and mission-relevant behavior. By linking current operational states to the likelihood of meeting future performance requirements, it offers a quantitative basis for predictive reliability assessment. The best performance is achieved by an XGB model, whose mission capability estimation roughly doubles the number of conducted missions up to a failure by avoiding risky missions in comparison to unfiltered mission acceptance. Full article