Search Results (17,673)

This paper presents a distributed closed-form control strategy for multi-unmanned aerial vehicle (multi-UAV) formation flight in cluttered environments. We propose a virtual-centroid-based architecture that reduces leader dependency while maintaining precise geometric configuration. A virtual-centroid navigation strategy generates reference trajectories for formation coordination. For collision avoidance, a generalized p-norm distance function accurately assesses collision risks for diverse obstacle geometries. An event-triggered mechanism incorporating velocity-dependent conditions produces amplitude-modulated, continuity-preserving avoidance vectors. A virtual navigation trajectory dynamically fuses avoidance information with reference tracking, enabling seamless coordination of tracking and collision avoidance. Closed-form controllers are derived for three-degree-of-freedom (3-DoF) dynamic formation control. Safety guarantees and asymptotic convergence in the nominal case are established via generalized Lyapunov analysis for non-smooth dynamical systems. Comparative simulations demonstrate that the proposed method achieves trajectory smoothness comparable to artificial potential field (APF). Full article

Coastal wetlands are important sinks for heavy metals, yet the linkage between vertical redistribution, quantitative source contributions, and ecological–health risk drivers remain insufficiently understood. This study collected the stratified sediment samples from three depth intervals (0–20, 20–40, and 40–60 cm) from 28 representative sites in the coastal wetlands of western Bohai Bay, and evaluated the spatial distribution, vertical variation, pollution status, potential sources, and ecological–human health risks of eight heavy metals (Cr, Ni, Cu, Zn, As, Cd, Hg, and Pb). The mean concentrations were below the Class I limits of the Marine Sediment Quality Standard. Most metals were close to or slightly below regional background values, whereas Cu and As showed mild enrichment and Cr was higher than values reported for Bohai Bay and Hangzhou Bay. Vertical profiles were generally homogeneous, with weak enrichment of specific metals, probably due to sediment resuspension, tidal disturbance, and bioturbation. Pollution assessment based on the geoaccumulation index (Igeo), Nemerow pollution index (P_N), and pollution load index (PLI) consistently indicated low contamination levels, with Hg and Pb as the main contributors to the regional pollution load. Source apportionment indicated that heavy metals were jointly influenced by lithogenic background (38.9%), atmospheric deposition (31.1%), and local anthropogenic activities (30.0%). Ecological risk assessment showed that the integrated risk index (RI) remained within the low-risk category, although Hg consistently fell within the moderate-risk range and Cd approached the moderate-risk threshold. Health risk assessment showed that both non-carcinogenic and carcinogenic risks were within acceptable limits for all receptor groups. Children had higher risks in core residential areas, whereas adults showed higher risks in non-core industrial–agricultural zones because of increased exposure frequency. The source–risk analysis indicates that non-carcinogenic risk is mainly associated with background-derived Cr, whereas carcinogenic risk is primarily linked to anthropogenic As inputs. These findings indicate that source contributions and risk contributions are not necessarily consistent, highlighting the need for source-oriented risk management in industrialized coastal wetlands. Full article

Background: Hypoxia signaling and the circadian clock exhibit extensive molecular crosstalk, but how endogenous circadian timing influences behavioral responses during high-altitude exposure remains incompletely understood. Methods: Male C57BL/6J mice were exposed to hypobaric hypoxia equivalent to an altitude of 6000 m. Wheel-running activity was continuously monitored under 12 h light/12 h dark (LD) cycle and constant-dark conditions to evaluate locomotor activity, rhythm amplitude, circadian phase, and free-running period. After 48 h of exposure, whole-hypothalamus samples were collected across the circadian cycle for time-series RNA sequencing, rhythmicity and pathway-enrichment analyses, and qPCR validation. In a separate experiment, hypoxia was initiated at ZT2 or ZT14 to assess circadian-phase-dependent behavioral responses. Results: High-altitude exposure acutely reduced locomotor activity and rhythm amplitude and subsequently delayed behavioral circadian phase under a LD cycle, whereas the free-running period under constant darkness remained unchanged. Transcriptomic analysis revealed extensive remodeling of rhythmic gene expression in the whole hypothalamus, involving multiple signaling and metabolic pathways. Relaxin-related signaling emerged as a candidate pathway associated with hypoxia-induced temporal transcriptional remodeling, and selected core clock genes and relaxin pathway-associated genes showed altered temporal expression profiles. Furthermore, exposure initiated at ZT14 produced greater locomotor suppression than exposure initiated at ZT2. Conclusions: High-altitude exposure disrupts behavioral circadian organization and remodels hypothalamic rhythmic transcription. These findings suggest that endogenous circadian timing modulates behavioral sensitivity to hypoxic stress. Full article

Silicone gel (SG) is an important soft encapsulation dielectric for high-voltage power modules, yet its limited insulation performance under high electric fields and elevated temperatures restricts its practical application. Herein, an ultralow loading of the organic molecular semiconductor anthrone (ET) was introduced into silicone gel to simultaneously improve dielectric properties and thermal stability. SG-ET_0.5 exhibited the best overall performance, with a breakdown strength of 29.14 kV/mm at 25 °C, 19.57% higher than that of pristine SG, and retained 22.86 kV/mm at 150 °C with only a 21.56% reduction. The relative permittivity increased to 3.16 and 2.85 at 25 °C and 200 °C, respectively. The partial discharge inception voltage increased from 3.1 to 4.8 kV, while both discharge frequency and amplitude were markedly reduced. Moreover, SG-ET_0.5 showed an increased 5% weight-loss temperature of 370 °C, together with slightly increased thermal conductivity and a reduced coefficient of thermal expansion. Mechanistic analysis suggests that the low-lying LUMO level and molecular characteristics of ET may contribute to the increased deep-trap density and enhanced electron-capturing tendency of the composites, thereby helping to suppress electron avalanche development and partial discharge. This work offers a molecular-level strategy for improving the electrical insulation performance of silicone gel dielectrics for high-voltage power modules. Full article

Background/Objectives: Image-guided adaptive brachytherapy is a core component of definitive treatment for locally advanced cervical cancer (LACC). However, implantation remains challenging in bulky, asymmetric, or anatomically complex tumors, where standard applicator geometry or purely straight interstitial trajectories may be insufficient for individualized target coverage. This study evaluated the real-world implementation of a patient-specific 3D-printed template-guided adaptive brachytherapy workflow for complex LACC. Methods: We retrospectively reviewed 120 consecutive patients with FIGO 2018 stage IB3–IVA cervical cancer treated with definitive chemoradiotherapy followed by high-dose-rate image-guided brachytherapy between March 2023 and March 2025. All patients were treated using a patient-specific 3D-printed template-guided hybrid intracavitary/interstitial workflow integrating CT/MRI-based target assessment, individualized catheter trajectory planning, template fabrication, implantation verification, and adaptive treatment planning. Straight-channel or curved-channel guidance was selected according to residual tumor geometry and pelvic anatomy, with flexible plastic interstitial catheters used for curved or anatomically constrained trajectories. Procedural deliverability, dosimetry, toxicity, early clinical outcomes, and exploratory dose–outcome patterns were analyzed. Results: The median HR-CTV volume was 55.9 cm³, and the median HR-CTV D90 was 92.9 Gy EQD2. Median organ-at-risk D2cc values remained within contemporary institutional and guideline-consistent constraints. A total of 555 template-guided HDR brachytherapy fractions were delivered. The median applicator-and-catheter placement time was 4.21 min per fraction, with a median of 7.25 implanted channels. Minor and major insertion-related bleeding occurred in 10.8% and 1.7% of patients, respectively. At a median follow-up of 20.1 months, estimated 3-year overall survival, progression-free survival, local recurrence-free survival, regional recurrence-free survival, and distant metastasis-free survival were 77.9%, 76.8%, 94.3%, 98.0%, and 86.2%, respectively. Late grade ≥ 3 gastrointestinal and genitourinary toxicities occurred in 2.5% and 1.7% of patients, respectively, with no grade 4–5 events. Exploratory dose–outcome analyses suggested hypothesis-generating dose–outcome patterns, but these findings were not intended to define or validate a clinical dose threshold. Conclusions: This real-world implementation study supports the feasibility of patient-specific 3D-printed template-guided adaptive brachytherapy for complex LACC. By translating CT/MRI-based individualized trajectory planning into template-guided intracavitary/interstitial catheter placement, this workflow achieved guideline-consistent target coverage, acceptable organ-at-risk doses, efficient procedural delivery, and low severe toxicity within the available follow-up. Dose–outcome findings remain exploratory and require validation in more mature cohorts. Full article

To clarify the pollution characteristics and source composition of heavy metals in the paddy soils of the Yellow River irrigation district of Ningxia, a total of 515 surface soil samples were collected, and the concentrations of As, Hg, Pb, Cd, and Cr were measured. Regional-scale pollution assessment and source apportionment were conducted using the geo-accumulation index, spatial interpolation analysis, and the Positive matrix factorization (PMF) model. Based on the regional pollution assessment and spatial distribution patterns, a representative area with relatively elevated Cd accumulation and more pronounced anthropogenic influence was selected for local-scale isotope investigation. Eight paddy soil samples and potential end-member samples were collected, and, combined with literature-based end-member data, Pb and Cd isotopes were analyzed using the MixSIAR Bayesian (version 3.1.12) mixing model to further constrain the sources of Pb and Cd in village soils. The results showed that some sampling points in the study area exceeded the soil background values, but none of the points surpassed the screening values for agricultural soil pollution risk, indicating that the overall risk of paddy soils in the study area remained low. Geo-accumulation index results indicated that As, Pb, and Cr were predominantly classified as unpolluted, whereas Hg and Cd showed more pronounced accumulation, with most sampling points reaching unpolluted to moderately polluted or higher. PMF results revealed that heavy metals in the study area primarily originated from natural sources, agricultural activities, coal combustion-related sources, and industrial–traffic mixed sources. Cd was mainly influenced by agricultural sources, Hg was primarily affected by coal combustion and related industrial activities, and Pb exhibited a mixture of multiple sources. Local isotope analysis in the representative area further indicated that industrial and agricultural sources were the main contributors to soil Cd, accounting for 34.3% and 33.1%, respectively. Pb was primarily derived from agricultural activities (38.1%), while coal emissions, industrial sources, natural sources, and traffic contributed 19.2%, 18.3%, 16.9%, and 7.5%, respectively, indicating a complex mixture of agricultural, industrial, coal-combustion, natural, and traffic-related inputs. The combined application of PMF and Pb/Cd isotopes allowed for constraints on heavy metal sources at both regional and local scales, providing a scientific basis for pollution control and agricultural safety management in paddy soils of the Yellow River irrigation district. Full article

There is currently a need for high-value applications of vinegar residue, a major byproduct generated during vinegar production, in order to benefit the environment and economic development. Melanoidins exist in vinegar residue as brown and bioactive macromolecules which are produced during the vinegar brewing process. However, the physicochemical characteristics and potential immunomodulatory activity of melanoidins from vinegar residue (VRM) have yet to be clarified. In this study, VRM exhibited structural heterogeneity, with a molecular weight of 9005.42 Da. Carbohydrates were the dominant component, accounting for 57.86 ± 3.36% (w/w), and xylose was the primary monosaccharide, with molar ratios of 53.15%. In addition, microstructural observations showed clear edges and a relatively smooth surface in VRM samples. Spectral analysis with FTIR showed that VRM has broad-spectrum ultraviolet absorption capacity and contains hydroxyl groups and unsaturated structures. Meanwhile, VRM exhibited higher antioxidant capacity than vinegar melanoidins according to ABTS and FRAP. Furthermore, the effects of VRM on immunomodulation were investigated in macrophages. VRM significantly induced phagocytic capacity and the secretion of NO, TNF-α, and IL-6. VRM at 800 ug/mL effectively exerted an immunomodulatory effect, which was associated with the TLR4-mediated NF-κB pathway. These findings demonstrate that VRM has a polysaccharide skeleton cross-linked with proteins and polyphenols, and possesses antioxidant and immunomodulatory properties. It will provide a novel and functional product for the efficient utilization of vinegar residue. Full article

To ensure the safety and stability of single point mooring (SPM) systems operating in shallow waters, this paper investigates the influences of shallow-water effects on mooring systems under different water depth-to-draft ratios. For the pile-founded column single point mooring system in shallow sea areas, based on the numerical calculation method verified by model tests, frequency domain and time domain calculations are carried out to study the specific impact of shallow water effects on the hydrodynamic parameters of the hull, and the critical water depth-to-draft ratios applicable to the two second-order wave load calculation methods (Newman approximation and Pinkster approximation) are analyzed. At the same time, the specific impact of shallow water effects on the dynamic response of the mooring system under three different hull loading conditions at the same and different water depth-to-draft ratios is studied, and the critical water depth conditions for bottom contact in each loading condition are summarized. The results show that the shallow water effect has a significant impact on the hydrodynamic parameters such as RAO of the hull response, especially in the low-frequency response region. There are obvious differences between the Newman approximation and the Pinkster approximation methods. In shallow water conditions, the Pinkster approximation method has a more accurate calculation effect, and when the water depth-to-draft ratio reaches a certain critical value, the calculation results of the two approximation methods are basically consistent. For the same and different water depth-to-draft ratio conditions, the amplitude of the hull motion in the full-load draft state is greater than the other two loading conditions, but the response results of the cable tension are opposite. The research results reveal the specific influences of shallow-water effects on pile-supported single-point mooring (SPM) systems, which can provide references for the safety and stability design of mooring systems and bear great engineering significance for advancing the deployment of single-point mooring systems in shallow water regions. Full article

Edible mushroom polysaccharides have attracted considerable attention because of their diverse biological activities, particularly their antioxidant potential. However, efficient extraction of these polysaccharides remains challenging due to the rigid chitin–β-glucan network of fungal cell walls. In this study, polysaccharides from Termitomyces albuminosus were extracted using hot water extraction (HWE), ultrasound-assisted extraction (UAE), and ultrasound-assisted aqueous two-phase extraction (UA-ATPE). Extraction conditions for each method were optimized using Box–Behnken response surface methodology, and the effects of different extraction strategies on polysaccharide yield, physicochemical properties, and antioxidant activity were systematically compared. Among the three methods, UAE produced the highest polysaccharide yield (110.32 ± 3.68 mg/g). The extraction strategy significantly influenced the molecular weight distribution and monosaccharide composition of the crude polysaccharides. The crude UAE extract was further purified by DEAE-52 anion-exchange chromatography, yielding the major antioxidant-active fraction eluted with 0.1 M NaCl (designated ATPs-0.1M), which was identified as an acidic heteropolysaccharide with an average molecular weight of 6.37 kDa and composed primarily of glucose, mannose, galactose, xylose, glucuronic acid, rhamnose, and fucose. In vitro antioxidant assays demonstrated that TAPs-0.1M exhibited stronger DPPH radical scavenging, hydroxyl radical scavenging, and ferric reducing activities than the other purified fractions under the tested conditions. The results indicate that different extraction strategies are associated with distinct physicochemical characteristics and antioxidant activities of T. albuminosus polysaccharides. These findings provide a practical basis for selecting appropriate extraction methods and support the further development of T. albuminosus polysaccharides as natural antioxidant ingredients. Full article

Volatile organic compounds (VOCs) are the main precursors of ozone (O₃) and secondary organic aerosols (SOAs), posing a significant threat to the environment and human health. In this study, the characteristics, potential for the generation of O₃ and SOAs, sources and health risks of volatile organic compounds were investigated based on annual monitoring data for 2021 in Dezhou, which is located in the northwest of Shandong Province, China, and adjacent to the Beijing–Tianjin–Hebei region. The results showed that the ambient VOC concentrations were lower in spring and summer and higher in autumn and winter. The species contributing to the O₃ formation potential (OFP) and SOA formation potential (SOAFP) varied by season, but those with high contributions were all olefins and aromatic hydrocarbons. O₃ pollution occurred frequently in summer, with a proportion of 40.22%. Focusing on summer, six sources were identified through the positive matrix factorization (PMF) model, with the petrochemical industry (26.1%) and combustion (25.6%) being the primary sources. The non-carcinogenic risk values of the involved 18 toxic VOCs were all within the safety threshold, while the carcinogenic risk of benzene was regarded as low-probability under long-term exposure. This study provides significant support for targeted control of air pollutant emissions and improvement in regional air quality. Full article

Background and Objectives: Evidence on the acute effects of caffeine in female team-sport athletes is limited. This study aimed to quantify the acute effects of caffeine on female team-sport athletes across physical performance, sport-specific performance, physiological responses, perceptual responses, and cognitive performance and determine moderators. Methods: PubMed and Web of Science were systematically searched for randomized, placebo-controlled crossover trials of acute, dose-defined caffeine in female team-sport athletes. Effect sizes were expressed as Hedges’ g and synthesized within each domain using a three-level CHE model with CR2 cluster-robust variance estimation and Satterthwaite degrees of freedom; 95% confidence intervals and prediction intervals were reported. Risk of bias (RoB 2), methodological quality (PEDro), and certainty of evidence (GRADE) were assessed. Results: Twenty-six studies were included, comprising 26 randomized, blind, placebo-controlled crossover trials. As a descriptive cross-domain summary, acute caffeine intake showed a small overall effect when all available domains were pooled (Hedges’ g = 0.24, 95% CI 0.13 to 0.35); however, because these domains represent different constructs, domain-specific estimates were considered the primary interpretable findings. For physical performance, caffeine showed a small favorable effect (g = 0.32, 95% CI 0.22 to 0.42), with statistical evidence for repeated sprint ability (g = 0.43), agility or change in direction (g = 0.42), sprint or speed performance (g = 0.39), anaerobic power (g = 0.30), and jumping performance (g = 0.29). For sport-specific performance, the pooled estimate indicated a small favorable effect but did not reach conventional statistical significance (g = 0.36, 95% CI: −0.01 to 0.73). Exploratory sub-indicator analyses, each based on only a few studies, suggested possible favorable directions for sport-specific locomotion or running performance (g = 0.46) and throwing or ball-speed outcomes (g = 0.19), whereas evidence was insufficient for shooting or scoring accuracy. Physiological outcomes were direction-aligned to the value conventionally regarded as favourable for each indicator (i.e., lower heart rate, lactate, and glucose), so that positive values denote the conventionally favourable direction; because the domain aggregates indicators of differing clinical desirability, its pooled value is a descriptive summary only and showed no clear domain-level direction (g = −0.05, 95% CI −0.31 to 0.21). The heart rate submetric showed a statistically detectable difference (g = −0.30), indicating that caffeine increased heart rate, the expected pharmacological response to a stimulant rather than an adverse effect; there were no clear effects on blood lactate or blood glucose. Perceptual responses improved modestly (g = 0.42), largely through reduced rating of perceived exertion (g = 0.35). Cognitive performance, based on only four studies with low degrees of freedom and wide uncertainty, showed a nonsignificant direction (g = 0.37) with no clear evidence for reaction time or cognitive accuracy, and these data should not be interpreted as showing that caffeine improves cognitive performance in female team-sport athletes. Exploratory moderator analyses did not provide statistically reliable evidence of moderation by caffeine dose, timing of intake, formulation or source, sport type, competitive level, habitual caffeine intake, or blinding status. Conclusions: Available evidence most consistently supports small, outcome-specific benefits of acute caffeine for physical performance and reduced perceived exertion. Evidence for sport-specific skills and cognitive outcomes remained uncertain, based on few studies per outcome and not supporting a general benefit. Current data do not support dose-, timing-, formulation-, habitual-intake-, sport-, or population-stratified recommendations. Future trials should be adequately powered, prospectively report menstrual-cycle phase, hormonal-contraceptive use, habitual caffeine intake, and adverse symptoms, and verify the integrity of blinding. Full article

Unauthorized unmanned aerial vehicle (UAV) intrusions in sensitive areas such as airports have made accurate UAV detection and localization a pressing need. Acoustic sensing is passive and weather-independent, but conventional microphone arrays require many elements and a large aperture. This paper proposes an acoustic vector sensor (AVS)-based method, termed Covariance Enhancement and Confidence-guided Tracking for 3D Acoustic Localization (CECT-3DAL). A single AVS measures the sound pressure and three-axis particle velocity at one point. Adaptive diagonal loading improves the robustness of the covariance matrix at a low signal-to-noise ratio (SNR). An exponential spectral enhancement strategy sharpens the spatial spectrum peaks for direction estimation, and an eigenvalue-ratio-based confidence drives confidence-weighted smoothing of the angle sequences. Meanwhile, a dual-sensor geometric model provides a closed-form three-dimensional solution. In simulations, the azimuth and elevation root-mean-square errors (RMSEs) were below 1.5° for SNR above 4 dB. In an anechoic chamber, confidence-weighted smoothing reduced the azimuth and elevation standard deviations from 4.34° and 2.63° to 1.46° and 0.86°. In field experiments, the hovering azimuth stayed within a 90% span of 2–3.5°, with an average horizontal RMSE of 0.209 m against a GPS reference, and trajectories under various flight modes remained continuous and smooth. The proposed method offers a compact, passive, and low-cost solution for counter-UAV acoustic surveillance. Full article

This paper focuses on the fixed-time distributed optimization problem with time-varying cost functions in multi-agent systems (MASs). For the scenario where all agents share the same Hessian matrix, a control framework for minimizing the global cost function is proposed based on the zero-gradient-sum (ZGS) algorithm. Specifically, integral sliding mode is employed to achieve the initial optimality of local objective functions, thereby satisfying the initial conditions required by the ZGS algorithm. Furthermore, for the case with heterogeneous Hessian matrices among agents, a distributed optimization algorithm integrating distributed gradient estimation and the prediction-correction method (PCM) is designed. Specifically, the distributed gradient estimation enables each agent to reconstruct the global objective gradient information of the system within a fixed time. Both proposed algorithms can achieve fixed-time convergence, and the inverse of the Hessian matrix is approximated online using a zeroing neural network (ZNN), which significantly improves computational efficiency. Finally, numerical simulations are conducted based on the charge balance problem in smart grids to verify the effectiveness and superiority of the proposed algorithms. Full article

To address the weak interfacial transition zone and insufficient mechanical properties of recycled aggregate pervious concrete, this study proposes a dual modification strategy using basalt fibers and ultra-fine mineral powder. The macroscopic mechanical and hydraulic properties of the material were analyzed through orthogonal experiments. Techniques including X-ray diffraction, scanning electron microscopy, and micro-computed tomography were employed to systematically reveal the microstructural evolution and internal pore network topology of the modified system. Based on range analysis of mechanical stiffness and drainage efficiency, the optimal mix proportions were determined as 5–10 mm aggregate, a water–cement ratio of 0.31, and a fiber content of 0.50%. Microscopic tests confirm that the pozzolanic reaction of ultra-fine mineral powder increases matrix density and enhances the shear bond strength between fibers and the cement paste, enabling the physical bridging effect of basalt fibers. The dual modification exhibits a synergistic effect on load-bearing capacity and crack resistance. CT scan results show that the internal pore cross-sectional area follows a unimodal skewed distribution, with the characteristic distribution peak located at 3.5 mm². This homogeneous microporous network limits the critical defect size, optimizing the stress transfer path while ensuring fluid transport. Full article

High renewable penetration, distributed energy resources, and fast-varying electric loads are shifting smart-grid planning from energy-balance simulation toward quality-aware operational assessment. Full-unit benchmark models (FULL) preserve unit commitment, ramping memory, and reserve feasibility but are expensive for repeated annual studies, whereas conventional equivalent aggregation (EQ) can overstate the realizable flexibility of heterogeneous units. This paper proposes quality-aware flexibility-envelope aggregation (QFEA), which separates units by inherited boundary state, ranks them by renewable-following flexibility, constructs conservative cluster envelopes, and couples reduced optimization with feasible disaggregation and state write-back. The model coordinates renewable curtailment, reserve sufficiency, tie-line ramping, and a normalized quality-stress proxy without claiming to replace detailed power-flow, harmonic, or electromagnetic studies. In the nominal single-region case, QFEA reduces the number of commitment objects by 46.2% and computation time by 63.7%, while limiting total-cost deviation to 1.1% and renewable-curtailment deviation to 0.2 percentage points. In 20 matched 24-h stress scenarios, its mean quality-stress index is 2.56%, compared with 2.58% for FULL and 6.57% for EQ. A separate 13–104-unit simplified scaling test keeps inverse-mapping closure error below 5.2 × 10⁻⁹ MWh and disaggregation below 1.3% of measured end-to-end time. The results identify QFEA as a traceable intermediate model for renewable-integration screening when annual computational efficiency and implementable unit trajectories are both required. Full article