Search Results (1,719)

Accurate cloud detection remains a significant challenge due to the spectral ambiguity between clouds and bright or heterogeneous surfaces (e.g., snow, desert). While multi-angle and polarization data offer rich information, the discriminative power of joint spectral analysis for resolving these ambiguities has been underexploited. In this work, we demonstrate that physically motivated spectral band ratios and differences can robustly enhance cloud signatures. Motivated by this insight, we propose a novel deep learning framework, the Multi-angle Polarization Feature Pyramid Structure (MP-FPS), that explicitly leverages joint spectral features as discriminative priors. Our architecture employs a dual-branch network to disentangle and adaptively fuse spectral and multi-angle polarization modalities. Within this framework, a hierarchical, multi-scale cross-channel multi-angle fusion module dynamically captures spatial–spectral–angular dependencies, enriching the structural representation of clouds. Furthermore, a channel-space dual-path attention mechanism refines sub-pixel responses, significantly improving detection accuracy in challenging regions such as cloud edges and thin cirrus. Evaluated on the global POLDER-3 dataset, MP-FPS achieves a mean Intersection over Union (mIoU) of 0.8662 across diverse surface types, surpassing the official baseline by 12.4%. This study establishes joint spectral analysis as a critical enabler for high-precision cloud masking, and demonstrates its synergistic value when integrated with multi-angle polarimetric information in a unified deep architecture. Full article

Different cyanobacterial species have been shown to be a valuable source of biologically active compounds with immunomodulatory activity. To date, little is known about members of the genus Tolypothrix (Cyanophyceae). Therefore, the present study focuses on five Tolypothrix strains (T. tenuis PACC 5497, T. tenuis PACC 8648, T. distorta SAG 1482-2, T. distorta CCALA 194, Tolypothrix sp. PACC 5501) that were not previously evaluated for specific morphological characteristics and immunomodulatory potential toward human immune cells. Cyanobacterial cultures were studied by light and transmission electron microscopy (TEM). Peripheral blood leukocytes were isolated from patients with inflammatory conditions and treated ex vivo with Tolypothrix non-polar extract fractions. Following treatment, the cells were analyzed by flow cytometry, and cytokine concentrations in culture supernatants were quantified by ELISA. Light microscopy observations showed that the cultures established from four of the strains have morphological features that correspond to T. tenuis Kützing (1843) ex Bornet et Flahault 1887 and T. distorta Kützing (1843) ex Bornet et Flahault. TEM analyses indicated parietal arrangement of cellular thylakoids in all strains, but T. distorta CCALA194 and Tolypothrix sp. PACC 5501 also displayed fascicular thylakoid arrangement. Immunophenotypic analyses revealed significantly increased proportions of T, NK, and B lymphocytes in leukocyte cultures treated with Tolypothrix extracts compared to the untreated controls. The concentrations of proinflammatory cytokines were lower in the culture medium of treated cells, while levels of the anti-inflammatory cytokine interleukin-10 remained stable, except in cultures treated with T. distorta SAG 1482-2 extract. The present study provides the detailed morphological characteristics of five strains of the genus Tolypothrix and indicate that non-polar extract fractions derived from the strains exert immunomodulatory effects on human leukocytes. Full article

Weak-echo ship target detection in GNSS-based bistatic synthetic aperture radar is severely limited by the coupled effects of burst-type strong windows and polarization mismatch, cross-frequency mis-registration, and long-sequence chain drift in dual-frequency dual-polarization observations. To address these issues, this paper proposes DFDP-QuadDiff, a dual-frequency dual-polarization quad-differential framework for weak-echo ship target detection using B1/B3 × horizontal–horizontal (HH)/vertical–vertical (VV) four-channel complex range-time data. The proposed framework integrates polarization-consistency-driven strong-window suppression, intra-band adaptive polarimetric synthesis, joint delay–Doppler–phase cross-frequency registration, segment-wise Jones drift calibration, and quality-aware final fusion in a unified hierarchical processing chain. In this way, multi-source inconsistencies are progressively constrained and suppressed from the polarization level to the segment level before final accumulation and detection are performed. Experimental results on self-developed four-channel GNSS-S demonstrate that, relative to the best raw single-channel result, the proposed framework increases the median SCR from 6.51 dB to 9.04 dB (+2.53 dB), improves the P10 SCR from −1.76 dB to 3.05 dB (+4.81 dB), and raises the track continuity from 0.85 to 0.97. In addition, the standard deviation of segment-wise delay drift is reduced from 0.97 bin to 0.29 bin, and positive multi-scale accumulation gains are maintained up to the second-long integration range. These results indicate that the proposed framework not only substantially enhances the stability, continuity, and long-time integrability of weak-target responses under low-SNR maritime conditions, but also maintains robust gains under weak-visibility, interference-dominant, and mismatch-sensitive local conditions in the stratified evaluation, thereby establishing a physically interpretable and implementation-ready solution for collaborative weak-target detection in dual-band dual-polarization GNSS-S. Full article

The practical application of inorganic ferroelectric fillers in flexible piezoelectric composites is critically constrained by low polarization efficiency and severe interfacial incompatibility with polymer matrices. Herein, we report a multi-level in situ surface modification strategy that simultaneously addresses both limitations. High-purity one-dimensional tetragonal barium titanate nanofibers (BTO NFs) are first synthesized via sol–gel electrospinning combined with a two-step gradient annealing process, which precisely controls phase evolution and preserves structural continuity. To overcome the detrimental acid-induced degradation of BTO NFs during functionalization, a polydopamine (PDA) buffer layer is first conformally coated, followed by the liquid-phase deposition of a conductive polypyrrole (PPy) shell, forming a robust core–shell PPy@PBT NFs architecture. Incorporating only 4 wt% of these multifunctional fillers into a poly(vinylidene fluoride) (PVDF) matrix yields a dramatic enhancement in electromechanical performance. The resulting flexible piezoelectric energy harvesters achieve a piezoelectric coefficient (d₃₃) of 28.7 pC/N, an output voltage of 13 V, and an output current of 0.7 μA, representing substantial improvements over unmodified filler systems. This synergistic enhancement originates from the PDA-mediated interfacial stress transfer and the PPy-induced Maxwell–Wagner polarization intensification, establishing a robust and generalizable paradigm for high-performance flexible piezoelectric composites in self-powered wearable electronics. Full article

The transition from acute kidney injury (AKI) to chronic kidney disease (CKD) represents a dynamic and multistage pathological process driven by maladaptive intercellular communication. Rather than resulting from isolated cellular injury, AKI-CKD progression unfolds through a spatially and temporally coordinated dysregulation of cellular networks. In the acute phase, damaged tubular epithelial cells act as instigators, releasing damage-associated molecular patterns (DAMPs) and activating a storm of inflammatory crosstalk among immune cells, endothelium, and fibroblasts. During the subacute repair phase, imbalance in macrophage polarization (M1 persistence/M2 dysfunction) and the emergence of senescent tubular cells with a senescence-associated secretory phenotype (SASP) together create a pro-fibrotic microenvironment. In the chronic phase, activated myofibroblasts—derived from multiple sources—establish self-sustaining feedback loops via autocrine signaling, mechanical memory from the stiffened extracellular matrix (ECM), and ongoing dialogue with immune and resident cells, ultimately leading to irreversible fibrosis. Current therapeutic strategies focused on single molecular targets often fail to disrupt this resilient network homeostasis. Therefore, we propose a paradigm shift toward spatiotemporally precise network-remodeling therapies, which require integrated use of liquid biopsy-based staging, smart nanocarriers for cell-specific delivery, and AI-powered multi-omics modeling. This review systematically delineates the evolving cell-to-cell communication networks across AKI-CKD continuum and highlights innovative strategies to intercept disease progression by targeting the pathophysiology of cellular crosstalk. Full article

State-of-charge (SOC) estimation for lithium-ion batteries in smartphones is complicated by nonlinear load variation, electro-thermal coupling, aging effects, and heterogeneous user behaviors. This study proposes a multi-physics coupled SOC estimation framework, termed the Multi-Physics Thermo-Electrochemical Coupled SOC Model (MTEC-SOC), to characterize battery behavior under representative user-load conditions within controlled ambient thermal boundaries. The model combines system-level power profiling, thermal evolution, voltage dynamics, and aging-related capacity correction within a unified framework. To support model development and validation, a dual-source dataset is established using laboratory battery characterization data and real-world smartphone behavioral data, from which users are classified into light, heavy, and mixed usage patterns. Comparative results against four benchmark models (M1–M4) show that MTEC-SOC achieves the highest overall accuracy, with average MAE, RMSE, and TTE error values of 0.0091, 0.0118, and 0.08 h, respectively. The results suggest distinct degradation tendencies across user types: calendar aging dominates under prolonged high-voltage dwell in light-use scenarios, whereas, within the tested thermal range, heavy-use scenarios exhibit stronger voltage sag, relative temperature rise, and polarization-related stress; mixed-use scenarios are characterized by transient responses induced by abrupt load switching. Sensitivity analysis further indicates that the predictive behavior of the model is strongly scenario-dependent, with higher-load operation within the calibrated range amplifying parameter perturbations. Overall, the proposed MTEC-SOC framework provides accurate SOC estimation and physically interpretable insight within the evaluated dataset and operating conditions, offering potential guidance for battery management and energy optimization in intelligent mobile terminals. Full article

Pulsed polarization of Au|YSZ gas sensors is examined to clarify the mechanism of NO_x detection under dynamic operation and to disentangle catalytic surface effects from electrochemical relaxation. Using gold electrodes with substantially lower catalytic activity than platinum explicitly enables this mechanistic separation. During pulsed polarization, periodic voltage pulses are followed by self-discharge under open-circuit conditions, and the response is measured based on the self-discharge rate. NO₂ consistently accelerates the self-discharge from the beginning, whereas NO slows the relaxation predominantly at later times. CO and H₂ produce similar delaying effects, and C₃H₆ shows no measurable influence under the tested conditions. Decreasing ambient O₂ slows the discharge and amplifies the NO₂ effect, which indicates that oxygen supply and surface exchange at the triple-phase boundary are rate determining. A Pt-containing catalytic overlayer drives local NO/NO₂ interconversion toward equilibrium so that both gases yield to an accelerated self-discharge. These findings support a mechanistic picture in which NO₂ provides effective oxygen equivalents that accelerate discharge, whereas NO, CO, and H₂ consume oxygen and slow down discharge. Overall, this establishes a materials-based approach for distinguishing between NO and NO₂ and evaluating the underlying mechanism during pulsed polarization. Full article

Background: The Global Positioning System (GPS) and wearable monitoring technologies are increasingly applied in sport science to quantify training load; however, data from female cross-country skiers in nations with emerging competitive programs remain scarce. This case series covering the complete national team roster analyzed the complete annual training cycle of the Korean women’s national cross-country skiing team (KCF) using GPS and heart rate-based wearable sensors. Methods: All three national team members were monitored throughout the 2022–2023 season (52 weeks), structured into General Preparation Period 1 (April–July), General Preparation Period 2 (August–November), and Competition Period (December–March). Individualized five-zone intensity thresholds were established through graded exercise testing on a roller ski treadmill with ventilatory threshold and blood lactate determination, independently assessed by two exercise physiologists (PhD level). Results: The total annual training volume was 667.72 h, comprising roller/on-snow skiing (54.0%), running (23.3%), and strength training (22.7%). The endurance-only intensity distribution demonstrated a polarized pattern (Zones 1–2: 91.5%). The total annual training distance reached 4673.30 km. The mean FIS points were 108.46 ± 38.60, and the mean VO₂max was 60.17 ± 6.11 mL·kg⁻¹·min⁻¹. Conclusions: When benchmarked against world-class female (WCF) standards (800–950 h annually), the overall training volume was approximately 18–30% lower. The relative strength training allocation (22.7%) exceeded typical WCF values (10–15%). These observations should be interpreted cautiously given the small sample size and cross-study comparison design, using published literature-based benchmarks. Full article

We present a minimal model that isolates the effect of hopping asymmetry on the thermal redistribution of particles in a bilayer graphene system composed of one pristine and one doped layer. The behavior of the system is governed by a single control parameter $\alpha$, which uniformly reduces the intralayer hopping in the doped sheet and defines the only source of spectral asymmetry. Particle conservation fixes the total density at all temperatures, so thermal effects appear exclusively as a redistribution relative to the zero-temperature reference state. This redistribution is quantified by the temperature-induced change of the layer populations, which measures how thermal occupation modifies the particle density in each layer without creating or destroying carriers. With this, the difference between the thermal population corrections of the doped and pristine layers defines the polarization. Thus, thermal excitations probe the asymmetric spectrum, exposing the intrinsic layer imbalance. Results show that for $0<\alpha <1$, band deformation produces unequal occupations between doped and pristine layers, and temperature amplifies this imbalance. The resulting polarization increases monotonically with temperature and systematically with hopping reduction, establishing a direct quantitative link between microscopic spectral asymmetry and macroscopic thermally induced layer imbalance. Full article

The Zeta-Minimizer Theorem establishes that the Riemann zeta function $\zeta \left(s\right)$ and the primes arise variationally as unique minimizers of a phase functional defined on a symmetric measure space $\left(X,\mu ,G\right)$ equipped with helical operators. Three fundamental axioms—strict concave entropy maximization (Axiom 1), spectral Gibbs minima with non-vanishing ground states (Axiom 2), and irreducible bounded oscillations with flux conservation (Axiom 3)—allow for the selection of the non-proper Archimedean conical helix as the sole topology satisfying all constraints. Primes emerge as indivisible minimal cycles in the associated representation graph $\Gamma$ (via Hilbert irreducibility and Maschke’s theorem), while the Euler product is recovered through the spectral Dirichlet mapping of the helical eigenvalues. The partial zeta product, $Z\left(s\right)=\prod _j{\displaystyle \frac{1}{1-p_j^{-s}}},s\in \mathbb{R}\left\{0\right\},$ constitutes the exact grand partition function of any finite subsystem. Numerical inversion of this product directly recovers the mixture frequency $s$ from any experimental compressibility factor $Z_{\mathrm{m}\mathrm{i}\mathrm{x}}$. Mole fractions $x_i\left(s\right)$, interaction parameters $\Delta \left(x_i\right)$, and the Lyapunov spectrum $\lambda \left(x_i\right)$ then follow deductively via the helical transfer matrix and the closed-form linear ODE for $\Delta$. Occupation numbers $N\left(x_i\right)$ attain sharp maxima precisely at Fibonacci ratios $F_r/F_{r+1}$, leading to the molecular prime-ID rule. For twelve representative purely binary (irreducible) systems spanning atomic noble gases, simple diatomics, polar molecules, and an aromatic ring, the residuals satisfy $|Z\left(s\right)-Z_{\mathrm{m}\mathrm{i}\mathrm{x}}|<1.5\times {10}^{-8}$. The resulting $\lambda \left(x_i\right)$ curves accurately reproduce critical points, liquid ranges, and thermodynamic anomalies with zero adjustable parameters. The Riemann Hypothesis follows rigorously as a theorem: the unique fixed point of the duality functor $s\mapsto 1-s$ that preserves the orthogonality condition $\sum {\mathrm{c}\mathrm{o}\mathrm{s}}^2{\theta }^k=1$ is $\mathrm{R}\mathrm{e}\left(s\right)=1/2$, enforced by Axiom 1 concavity and Axiom 3 irreducibility. The framework is fully deductive and parameter-free and extends naturally to arbitrary mixtures and multiplicities through the helical representation graph. It provides a variational unification of analytic number theory, spectral geometry, thermodynamic phase behavior, and the Riemann Hypothesis from first principles. Full article

Perennial deciduous trees such as Prunus avium undergo seasonal transitions, culminating in bud dormancy establishment that involves coordinated physiological and metabolic adjustments. Dormancy monitoring in orchard systems still relies primarily on temperature-based models and forcing assays, which rarely incorporate physiological or biochemical indicators. Here, we tested whether seasonal metabolic dynamics associated with dormancy progression differ between sweet cherry genotypes and whether these physiological differences are reflected in canopy-scale vegetation indices derived from satellite observations. Field measurements were conducted in two genotypes with contrasting chilling behavior (‘Regina’ and ‘210’) during the transition from vegetative growth to dormancy. Leaf gas exchange and chlorophyll fluorescence were monitored across the season, polar metabolites in floral buds were profiled by gas chromatography-mass spectrometry, and satellite-derived vegetation indices were used to characterize canopy dynamics. Dormancy progression was associated with declines in CO₂ assimilation, transpiration, PSII photochemical efficiency, and electron transport rate, accompanied by increases in intercellular CO₂ concentration and non-regulated energy dissipation. Metabolomic analysis revealed that genotype explained a larger proportion of metabolite variation than dormancy stage (PERMANOVA R² = 0.483, p = 0.001), while principal component analysis accounted for 79.7% of total variance. Fructose showed the strongest genotype difference during paradormancy I, corresponding to an approximately 9.5-fold increase in ‘Regina’. Pathway enrichment analysis highlighted starch and sucrose metabolism and pyruvate metabolism as the most represented pathways during dormancy progression. Satellite-derived vegetation indices captured seasonal canopy decline and were significantly associated with several physiological variables. These results provide an integrated description of physiological and metabolic adjustments during dormancy establishment in sweet cherry and highlight the potential of combining metabolomics, plant physiology, and open-access satellite observations to monitor phenological transitions in orchard systems at scalable spatial and temporal resolutions. Full article

Global urbanization has long been hampered by the “metrocentric priority” paradigm, with small towns—core hubs for urban–rural integration—severely undervalued in practical value. Amid China’s transition to high-quality urban–rural integration, unbalanced small town development has become a critical bottleneck for county-level factor flows, demanding systematic research to unlock their strategic value and resolve urban–rural dual predicaments. Existing studies suffer from scientific gaps including unidirectional linear cognition, insufficient complex system thinking, and weak interpretation of regional heterogeneity, remaining at the stage of static correlation description and failing to reveal the two-way reciprocal feedback logic between small towns and urban–rural integration. Meanwhile, the application of complex system theory in urban–rural research is still confined to theoretical narratives, which hinders the advancement of research from descriptive analysis to mechanism interpretation. Taking Henan Province (a typical agricultural and populous province reflecting China’s urban–rural development) as a case, this study builds a “local emergence–global synergy” framework based on complex system theory, establishes a dual indicator system for small towns’ multidimensional performance and county-level urban–rural integration, and integrates spatial statistical analysis, bidirectional regression and coupling coordination models to explore their cross-scale spatiotemporal evolution and reciprocal feedback during 2019–2023. Findings show the following: (1) The multidimensional performance of small towns presents a pattern characterized by polarized expansion of high-value regions and overall improvement of low-value regions, while county-level urban–rural integration evolves into a polycentric structure featured by central dominance and southern growth. (2) There is a significant two-way asymmetric relationship between small towns’ multidimensional performance and county-level urban–rural integration: the positive effect is significantly stronger than the reverse effect, and both direct impacts are significantly weakened after introducing economic variables, indicating that economic development serves as a key transmission channel. (3) The coupling mechanism presents three evolutionary paths with pronounced core–periphery spatial heterogeneity. Grounded in complex system theory, this study constructs a systemic analytical framework of “local emergence of small-town subsystems and global synergy of county-level systems”, verifies the core proposition of two-way interactions between subsystems and the overall system in the urban–rural complex giant system, and enriches the localized application of complex system theory and the urban–rural continuum theory in traditional agricultural regions of China. This study provides a foundational empirical paradigm for the in-depth exploration of nonlinear characteristics and threshold effects in future research. It offers theoretical support for policy formulation of county-level urban–rural integration in traditional agricultural regions of China, and it provides Chinese experiences for the Global South with similar contexts to explore inclusive urbanization pathways, promoting cross-cultural dialogue and practical transformation of urban–rural integration theory. Full article

Conducting polymer–metal nanocomposites are widely investigated as tunable photonic and optoelectronic media; however, reported property trends often remain empirical because electronic disorder at the absorption edge, refractive-index dispersion, free carrier dielectric response, and third-order nonlinearity are rarely quantified within a single, composition-controlled film series. This limitation is particularly relevant for electrochemically grown PANI coatings on transparent conductive substrates, where nanoparticle incorporation can simultaneously enhance polarization while introducing aggregation-driven heterogeneity. Here, Ag/PANI nanocomposite thin films were fabricated directly on indium tin oxide (ITO) by potentiostatic electrodeposition from an aniline/camphorsulfonic acid electrolyte containing controlled Ag nanoparticle loadings (5–15 wt.%). This study addresses the research gap by integrating complementary optical-disorder and dispersion formalisms with dielectric and nonlinear analyses to establish a composition structure optics map for device-relevant films. Ag incorporation narrows the indirect optical gap from 1.98 eV (PANI) to 1.81 eV (5 wt.%), 1.38 eV (10 wt.%), and 1.19 eV (15 wt.%), while markedly broadening the Urbach tail (0.377 eV → 1.28–1.64 eV at 5–10 wt.%). Wemple–DiDomenico modeling and Drude-type dielectric dispersion reveal strongly non-monotonic evolution of oscillator energetics and the carrier response, culminating in large bound-electron dielectric constants (ε_∞ up to 469.8) and plasma frequencies (ω_p up to 248 × 10¹² Hz) at 15 wt.% Ag. Third-order nonlinearity is substantially enhanced but composition-sensitive: χ³ increases from 6.73 × 10⁻⁹ esu (PANI) to ~7.6 × 10⁻⁸ esu at 5 and 15 wt.%, whereas the Kerr coefficient peaks at 25.91 × 10⁻⁷ esu for 5 wt.% and is suppressed at intermediate/high loading. These results demonstrate that the optimal nonlinear performance is governed by a disorder–dispersion balance and microstructure-dependent local-field effects rather than the Ag fraction alone. Full article

Measuring the service levels and spatial equity of urban parks constitutes a core research topic within the field of environmental justice. Against the backdrop of low-carbon urban transformation and sustainable development, this study constructs an ecological supply indicator calculation model for parks based on landscape ecology theory. Leveraging spatio-temporal big data such as Points of Interest (POI) and second-hand property transactions, it establishes a demand evaluation indicator system centered on human activity intensity. The study employs the Gini coefficient and location entropy to gauge the spatial equity of park supply–demand balance, utilizing the Z-score method to classify supply–demand matching types. An empirical case study is conducted in Shenzhen. Findings indicate that despite Shenzhen possessing abundant global-scale park resources, a Gini coefficient of 0.489 reveals significant deficiencies in the equitable provision of park services, with spatial distribution exhibiting pronounced social stratification. Specifically: (1) location entropy values exhibit an east-high, west-low spatial pattern; (2) areas with high location entropy are predominantly concentrated in Dapeng New District, rich in green space resources, where supply exceeds demand, creating an imbalance; and (3) areas with low locational entropy values are predominantly distributed in industrial clusters such as western Bao’an and western Longgang, exhibiting contradictory characteristics of low supply and high demand. Overall, the distribution of park and green space resources exhibits a polarized pattern. Full article

Desulfovibrio spp. are sulfate-reducing bacteria (SRB) associated with conditions such as inflammatory bowel disease (IBD) that are linked to intestinal barrier dysfunction (leaky gut). Previously, we reported that Desulfovibrio vulgaris (DSV) caused increased intestinal permeability by upregulating nuclear transcription factor Snail. However, the signaling mechanisms underlying this effect remain unclear. Glycogen synthase kinase-3 (GSK-3) is a serine/threonine kinase that maintains intestinal barrier integrity and negatively regulates Snail and promotes its degradation by proteasomes. Rapamycin has been shown to protect the intestinal barrier and is also known to activate GSK-3. In this study, we investigated whether DSV disrupts intestinal barrier function through modulation of GSK-3 signaling and whether rapamycin could counteract these effects. Using a previously established DSV-induced paracellular permeability model using polarized Caco-2 monolayers, here, we showed that DSV induced inhibitory phosphorylation of GSK-3. Pretreatment of cells with rapamycin prevented DSV- induced phospho- inactivation of GSK-3, suppressed Snail expression and nuclear localization, and significantly reduced DSV-induced barrier permeability. Inhibition of proteasomal degradation with MG132 abolished the protective effects of rapamycin on barrier permeability, supporting a role for GSK-3–mediated proteasomal regulation of Snail. Together, these findings identify GSK-3 signaling as a novel mechanism underlying DSV-induced intestinal barrier dysfunction and highlight rapamycin as a potential therapeutic approach strategy to protect intestinal barrier integrity in response to DSV. Specifically, targeting the GSK-3/Snail pathway may represent a promising strategy to mitigate SRB-associated intestinal barrier disruption. Full article