Search Results (3,919)

This paper describes a polarimetric, frequency-modulated continuous wave (FMCW) synthetic aperture radar (SAR) with an ultrawide bandwidth that spans 2–18 GHz. It is being developed as an airborne sensor called SKuSAR. The intent is to generate a set of sub-band images, thereby creating a multispectral SAR. This opens the prospect for new remote sensing algorithms that exploit variations in the scene’s polarization/frequency response occurring over the system’s three octaves of bandwidth. We describe the SKuSAR hardware and the processing steps applied to the FMCW data to create a multispectral SAR. The approach is practically demonstrated using data collected against calibration targets deployed in a field with the system mounted on a truck. This ground-based arrangement provided an inexpensive solution to test and fine-tune the system hardware and processing algorithms. A few complicating factors specific to the ground-based geometry were encountered, such as multipath signal contamination due to ground reflection and rather short data collections that affected attainable azimuth resolutions. Both these factors were identified and analyzed. The measured characteristics follow theoretical predictions rather well, giving confidence that the system meets its expected nominal performance once airborne, with the mentioned limiting factors absent or of reduced significance. Full article

In contrast to the well-established vicarious methods for satellite radiometric calibration, studies on polarimetric calibration remain relatively limited. This study presented a sun glint based in-flight polarization calibration method in which measurements of the degree of linear polarization (DOLP) at the top of atmosphere (TOA) are directly compared with theoretical simulations generated by an atmosphere-ocean coupled vector radiative transfer model. A well calibrated reference band is introduced to retrieve the instantaneous sea surface wind speed (WS), thereby improving the accuracy of simulated TOA DOLP. The dependencies of WS retrieval error on reference band wavelength, actual WS, and solar-viewing geometry are analyzed. The results show that the WS retrieval error generally decreases with increasing reference band wavelength and increases with WS and sun glint angle. A reference band with a wavelength longer than 670 nm and the highest radiometric calibration accuracy is recommended for WS retrieval. Under typical conditions, a WS retrieval error of approximately ±0.33 m/s is predicted, which is substantially lower than the ±2 m/s uncertainty commonly associated with meteorological reanalysis WS data. Theoretical TOA DOLP simulation errors are then quantified by considering typical uncertainties in atmospheric and oceanic input parameters across spectral bands from blue to SWIR under various solar-viewing geometries. Among the investigated factors, aerosol optical depth and aerosol model are the dominant sources to DOLP calibration uncertainty, accounting for more than 80% of the total error budget in most spectral bands. Chlorophyll concentration mainly affects the short visible bands. The WS effect can be reduced by using reference band retrievals instead of meteorological reanalysis data. The wind direction effect is negligible near the center of glint spots and under small solar zenith angle conditions, but it increases considerably with the sun glint angle under oblique illumination geometry condition. The contributions from ozone, and water vapor are negligible. Overall, the total TOA DOLP error increases with solar zenith angle, viewing zenith angle (i.e., longer atmospheric optical paths), and sun glint angle (i.e., weaker sun glint brightness). The errors exhibit weak wavelength dependence, with relative lower values in the short visible and SWIR bands and slightly higher values in the NIR bands. The typical total DOLP calibration error ranges from 0.0091 to 0.0125 across blue to SWIR spectral bands (according to the center of sun glint region with solar zenith angle of 30°). This study presents theoretical guidance for satellite in-flight polarization calibration using sun glint across blue to SWIR bands. As budgeted, this method can be effective for the validation of polarimeters with moderate DOLP accuracy (e.g., 0.01–0.02). Nevertheless, it may not be ideally suited to act as an absolute reference for high-accuracy polarimeters (e.g., 0.002). Full article

This study aims to comprehensively investigate the usability of white mulberry (Morus alba L.) leaf extract as a natural dye, including its fastness properties, antibacterial activity, and antioxidant activity. In the study, dyeing processes were carried out on cotton fabric, wool fabric, wool yarn, polyester, leather, and pine wood materials using different mordanting techniques (pre-, co-, and post-mordanting) and pH values (4 and 8). Copper-II-sulfate, iron-II-sulfate, alum, silver nitrate, Reşadiye clay, and Önal-1 [3% (v/v) NH₃ + 3% (w/v) Urea + 3% (w/v) CaC₂O₄] were used as mordants. Washing, light, rubbing, and perspiration fastness of the dyed materials were evaluated according to international standards, and color properties were analyzed using the CIE-Lab* system and Kubelka–Munk (K/S) values. Structural characterization of the extract was carried out using 1H-NMR, 13C-NMR, LC-MS/MS, and TLC. Antibacterial activity of the dyed materials was assessed using the disk-diffusion method, with undyed, extract-only, and mordant-only controls used to distinguish the contributions of the extract and the mordants. Ferric reducing antioxidant power (FRAP) evaluation across six solvent fractions revealed marked solvent-dependent efficacy, with the apolar hexane fraction exhibiting the highest reducing capacity (436.3 ± 12.45 µmol TE/g fw), followed by the chloroform (423.83 ± 11.76 µmol TE/g fw) and hexane/ethyl acetate (406.98 ± 10.23 µmol TE/g fw) fractions, whereas the polar methanol fraction showed the lowest reducing capacity (100.76 ± 4.32 µmol TE/g fw). This reducing potential was statistically associated with the enriched flavonoid and phenolic core constituents identified via LC-MS/MS, primarily hesperidin (8.365 ± 0.432 mg/g) and isoquercetin (0.645 ± 0.054 mg/g). Because only the single-electron-transfer FRAP assay was performed, no radical-scavenging (IC₅₀) metrics are reported. The reducing capacity is therefore interpreted cautiously as a collective property of the phenolic–flavonoid fraction, in which hesperidin and isoquercetin are the principal contributors rather than any single decisive compound. The results revealed that white mulberry leaf extract exhibited high K/S values (21.33 for cotton fabric and 27.91 for wool yarn) and excellent antibacterial activity, particularly when a silver nitrate mordant was used. LC-MS/MS analysis confirmed the presence of bioactive compounds, including hesperidin (8.365 mg/g), isoquercetin (0.645 mg/g), and vanillic acid (0.189 mg/g) in the extract. These findings indicate that white mulberry leaf extract is a plant-derived colorant with multifunctional potential for textile, leather, and wood substrates. The present work does not quantify the environmental footprint of the complete process; therefore, no overall sustainability advantage relative to conventional dyeing is claimed. Any future environmental assessment should include measured extraction energy, water consumption, mordant loading, residual-metal concentrations in spent baths, and wastewater-treatment requirements. Full article

Microfluidic confinement offers new opportunities for tailoring properties of nanomaterials by applying specific dynamic and wall effects. A vibrant approach is integration of microfluidic channels with lyotropic liquid crystals and luminescent additives, which offer a variety of tunable supramolecular organizations for applications in nanotechnology and biomedicine. This paper focuses on analyzing nanoscale and microscale properties of the nanomaterials represented by tetraethylene glycol and decaethylene glycol monododecyl ethers with integrated carbon dots. Orienting impact of microchannel surfaces was found to be responsible for additional microscale ordering of the intrinsic lamellar and hexagonal structures of these composites after the phase transition from the isotropic liquid to the liquid crystalline state. Controlled and varied shear stress resulted in additional planar orientation of the composites and provided them with anisotropic luminescence properties, which were not demonstrated by macroscopic samples. Incorporation of a bioactive compound into the liquid crystalline matrix allowed obtaining the specific and detectable anisotropic luminescence response of the nanomaterials. The datasets comprising hundreds of polarized microscopy images were successfully used for training the neural network and accurate recognition of the liquid crystal type in the composites. The results will contribute to developing AI-compatible microfluidic chips, which simulate the biological capillary environment and allow for tuning properties of luminescent nanomaterials for drug delivery and biomedical applications. Full article

Background: Influenza remains a significant global public health threat, causing substantial morbidity and mortality worldwide. While vaccination serves as the best preventive strategy, considerable interindividual variability in vaccine-induced immune responses persists. The ZBTB46 rs2281929 polymorphism (c.A31G; p.T11A; ACG>GCG), which corresponds to the evolutionarily conserved mouse mutation Zbtb46^T11A (c.A31G; ACT>GCT), has been associated with enhanced antibody responses to influenza vaccination in humans, though its functional mechanisms remain unknown. This study aimed to investigate how this mutation affects influenza vaccine immunogenicity using a knock-in mouse model. Methods: A Zbtb46^T11A knock-in mouse model was generated using CRISPR/Cas9 technology. Homozygous (HO) and wild-type (WT) mice were immunized with a quadrivalent influenza vaccine in a prime-boost regimen. Humoral immune responses were assessed by Enzyme-linked immunosorbent assay, hemagglutination inhibition (HI), and microneutralization (MN) assays. Antibody-secreting cells (ASCs) were quantified by Enzyme-linked immunospot assays. Germinal center B cells, plasma cells, plasmablast cells, conventional dendritic cell (cDC) subsets, and T helper (Th) cells were analyzed by flow cytometry. Statistical comparisons were performed using a two-sample t-test. Results: The Zbtb46^T11A mutation did not alter Zbtb46 protein expression or its abundance in cDCs. Following vaccination, HO mice exhibited significantly enhanced humoral responses, including higher HA-specific IgG titers, HI and MN antibody levels, and increased numbers of ASCs. Flow cytometry revealed elevated proportions of germinal center B cells and plasma cells in HO mice. Furthermore, HO mice showed a selective expansion of type 1 cDCs (cDC1s) and a concomitant increase in Th1 cell frequencies and IFN-γ-secreting cells, while cDC2 proportions and Th2 responses remained unchanged. Conclusions: The Zbtb46^T11A mutation is associated with enhanced influenza vaccine immunogenicity, concomitant with increased cDC1 proportions, Th1 polarization, and germinal center-dependent humoral immunity. These observed associations suggest a candidate mechanism whereby Zbtb46 modulation may shape adaptive immunity, though further functional studies are required to establish causality. These findings provide insights into host genetic variation in vaccine responsiveness and may inform personalized vaccination strategies. Full article

The tumor microenvironment (TME) is an innervated and neurochemically active setting. To date, its cholinergic and GABAergic signaling have largely been analyzed as separate systems, contributing to inconsistent findings across the literature. We propose a Calcium-Gated Excitability (CAGE) model, in which α7 nicotinic acetylcholine receptor (nAChR), α4β2 nAChR, GABA type A (GABA_A) and type B (GABA_B) receptors, and α2δ-1 converge on a single downstream variable: Ca²⁺ flux. α7 conducts Ca²⁺ directly; α4β2 may redirect cholinergic input toward GABA release; GABA_A and GABA_B set the direction of the calcium response through intracellular chloride-gradient state and opposing intracellular signaling branches; α2δ-1 sets the gain that determines whether depolarization reaches a functional threshold. The resulting calcium-axis configuration, defined by receptor functional state, chloride-gradient status, α2δ-1 gain, and ligand exposure, shapes Ca²⁺ output and constrains downstream biological responses. Under this framework, some divergent findings on acetylcholine, nicotine, and GABA become testable consequences of distinct calcium-regulatory configurations. CAGE yields testable predictions, including nonlinear nAChR dose–response curves, reversal of GABA_A polarity, α2δ-1-dependent signal scaling, and spatially heterogeneous Ca²⁺ states. Studies evaluating nAChR- and GABA-receptor-targeted therapies without prior calcium-axis stratification may not be underpowered; they may be asking the wrong question. Full article

Riming and aggregation are critical ice-phase microphysical processes in winter clouds, but their overlapping signatures and dynamic transitions pose challenges for conventional single-frequency radar detection. We introduce a novel gradient-based identification method using ground-based triple-frequency dual-polarization radar observations. By analyzing vertical gradients of triple-frequency radar variables, rather than their absolute values, we discern these microphysical processes through physically based thresholds that reflect particle growth regimes. This approach captures subtle spatiotemporal variations in riming and aggregation that conventional threshold methods would miss, particularly in resolving layered riming-aggregation transitions. The dynamic gradient-based method demonstrates enhanced physical consistency and adaptability near process boundaries, thereby improving the tracking of ice-particle evolution. These advances provide a pathway to refine microphysical parameterizations and enhance high-resolution snowfall forecasting. Full article

Neuroinflammation within the tumor microenvironment (TME) of central nervous system (CNS) neoplasms, particularly glioblastoma (GBM), is no longer viewed merely as a reactive phenomenon but rather as a major driver of gliomagenesis and malignant transformation. This process involves a shift from acute immune activation to a chronic, sterile state that reshapes the CNS borders and immune niches to favor tumor evasion. This narrative review provides a comprehensive mechanistically focused analysis of the mechanisms governing the inflammatory stroma in primary and metastatic brain neoplasms. It critically examines the ontogeny and transcriptomic profile of myeloid and glial populations, dismantling the binary M1/M2 polarization model in favor of a continuum of functional states determined by metabolic and oxygenation gradients. It also analyzes intracellular signaling cascades, the subversion of innate immunity sensors such as the cGAS-STING pathway, the epigenetic reprogramming of stromal cells, and the role of extracellular vesicles. The electrochemical integration of tumor cells into neuronal circuits via glutamatergic synapses and connexin 43 gap junction coupling is addressed in detail, defining the mitogenic impact of neuronal activity on the tumor. The inflammatory profiles of IDH-wildtype and IDH-mutant gliomas and of secondary brain metastases are contrasted. Finally, the correlates of functional neuroimaging, liquid biopsies, and resistance mechanisms to conventional therapies are analyzed, including the GIANT and SENIPERA clinical trials, CARv3-TEAM-E bivalent cellular immunotherapy preconditioned with the LDC + R regimen, and the accelerated approval of dordaviprone (Modeyso) in H3 K27M-mutant diffuse midline gliomas. Full article

This paper analyzes the systemic threat of election-related Foreign Information Manipulation and Interference (FIMI) and Generative Artificial Intelligence (GAI) across recent Latin American electoral cycles in Guatemala (2023), Ecuador (2025), and Honduras (2025). Integrating the FIMI behavioral taxonomy with the DISARM framework and systems dynamics, we compare the transition from traditional digital propaganda to industrialized “algorithmic campaigns” driven by deepfakes, voice cloning, and media impersonation. Methodologically, we audit a database of documented media impersonations alongside international electoral observation reports. Our comparative analysis suggests that even if synthetic content cannot be shown to directly alter individual votes, it appears to reshape the emotional and symbolic climate of elections, which appears to exacerbate affective polarization and institutional distrust. We contextualize these dynamics within the slop economy—a structural digital divide in information quality between digital elites and digital commoners. Arguing that top-down regulations are insufficient against these decentralized threats, we propose a decentralized democratic defense model based on Jean Cloutier’s émirec concept, introducing cognitive friction into digital consumption to foster bottom-up epistemic resilience. Full article

Reconfigurable intelligent surfaces (RISs) are emerging as a key enabling technology to engineer the wireless propagation environment in 5G/6G systems. This paper presents the design, characterization, and control of a high-resolution RIS targeting slowly time-varying scenarios, in which fine-grained and stable phase control is more valuable than fast reconfiguration. Starting from the OpenRIS unit-cell layout, the cell is re-optimized for single-polarization operation and continuous phase tuning through a single varactor diode, exploiting the full tuning range enabled by a high-resolution DAC infrastructure rather than multi-bit quantization. The unit cell is analyzed via full-wave 3D FEM simulation in COMSOL Multiphysics and optimized to maximize the reflection-phase excursion while limiting amplitude modulation across the 5G N78 band (3.60–3.78 GHz). The design is experimentally validated in a WR-284 waveguide fixture, exhibiting a phase excursion approaching the full ${360}^{\circ }$ near resonance, with an amplitude variation below 1 dB over the bias sweep at any given frequency, while the average reflection level decreases by about 2 dB from the center to the upper band edge. A fifth-order polynomial phase–voltage calibration feeds a lookup table driving a layered control system based on a Python HMI, a server, and STM32-driven 16-bit DACs. Experimental measurements confirm that the control chain delivers the commanded bias voltages to the addressed unit cells within measurement uncertainty; the array-level beamforming is assessed at simulation level under idealized (unit-magnitude) assumptions, while the experimental characterization of the assembled surface is left to future work. Full article

Background/Objectives: Chronic metabolic inflammation is associated with pro-inflammatory macrophage activation and mitochondrial dysfunction. Semaglutide, a widely used GLP-1 receptor agonist, has been reported to possess systemic anti-inflammatory properties, but its action on human macrophages, especially in the context of mitochondrial regulation, remains poorly understood. The aim of the study was to evaluate the direct effect of semaglutide on macrophage polarization and to investigate the roles of cAMP signaling and mitochondrial regulation in this process. Methods: THP-1 and U-937 monocytic cell lines were differentiated into macrophages and polarized into the M1-like phenotype using LPS/IFN-γ. Cells were treated with 100 nM semaglutide in the presence or absence of the adenylyl cyclase inhibitor SQ22536. Intracellular cAMP levels, mRNA expression of macrophage markers and key regulators of mitochondrial biogenesis (SIRT1 and PGC-1α), and levels of pro- and anti-inflammatory cytokines were determined. The COX-1/SDH-A and mtDNA/nDNA ratios were analyzed as markers of mitochondrial biogenesis. Results: Semaglutide induced cAMP accumulation in M0- and M1-like macrophages derived from both cell lines. This response was significantly attenuated by GLP-1R antagonist exendin(9–39), supporting the presence of functional GLP-1R signaling. Semaglutide supplementation during inflammatory polarization resulted in reduced levels of pro-inflammatory markers (CD80/CD86, TNF-α, IL-6) and increased expression of M2-associated genes CD206 and CD163 and secretion of the anti-inflammatory cytokine IL-10. Semaglutide also increased SIRT1 and PGC-1α expression, the COX-1/SDH-A ratio, and the mtDNA/nDNA ratio, suggesting activation of processes associated with mitochondrial biogenesis. All of the effects of semaglutide described above were attenuated by SQ22536, supporting an important contribution of cAMP signaling to these responses. Conclusions: Semaglutide acts directly on human monocytic cell line-derived macrophages, attenuating the M1-like program and promoting a shift toward a less inflammatory phenotype. These effects strongly depend on cAMP signaling and are accompanied by increased expression of SIRT1 and PGC-1α and mitochondrial changes consistent with enhanced biogenesis. Full article

Traditional microwave-absorbing metasurfaces struggle to integrate optical transparency with ultra-wideband and high-efficiency microwave absorption, severely limiting their deployment in optoelectronics-compatible electromagnetic protection. To address this constraint, we propose a transparent ultra-wideband microwave-absorbing metasurface based on multilayered indium tin oxide (ITO) films. The unit cell is constructed using a multilayered PMMA dielectric configuration, where ITO conductive layers are patterned as a top square patch, middle square rings, and a continuous bottom film. Full-wave parametric optimization, combined with multilayer resonant coupling, effectively extends the absorption bandwidth. We elucidate the underlying broadband absorption mechanism by analyzing electromagnetic field and surface current distributions at typical resonant frequencies. Furthermore, we systematically investigate the impacts of ITO sheet resistance, incident angle, and polarization state on absorption performance. A 6 × 6 array prototype is fabricated and experimentally characterized in a microwave anechoic chamber. The measured results demonstrate that the proposed metasurface achieves an absorptance exceeding 90% across 9.2–40.2 GHz, delivering a fractional bandwidth of 125.5%. The experimental responses are in good agreement with numerical simulations, and the fabricated prototype retains good optical transparency. Benefiting from the synergistic integration of ultra-wideband microwave absorption and superior optical transmissivity, this multilayer stacked metasurface offers a promising strategy for advanced optoelectronics-compatible stealth and transparent electromagnetic shielding applications. Full article

Polarization–spectral imaging information has theoretical advantages for camouflage-net recognition. However, for specific observation targets, the selection of effective spectral bands and polarization parameters, which are critical issues in engineering applications, remains unclear. Using a newly developed hyperspectral polarization imaging prototype, we conducted systematic outdoor observations of a grassland camouflage net placed over green grass at multiple viewing angles and different times of day. After evaluating and confirming the net’s camouflage effectiveness, we analyzed polarization-parameter spectral images of both the net and background under varying observation and solar altitude angles. The Fisher criterion was used to identify discriminative polarization parameters and spectral ranges. Effective bands were determined as S₁ at 675–696 nm, S₂ at 673–677 nm, S₃ at 607–616 nm and 625–700 nm, DoP at 676–700 nm, and DoLP at 668–680 nm. Grayscale images in these bands further verified the separability of the camouflage net from grass. These results provide experimental evidence and wavelength-parameter references for engineering applications of polarization–spectral imaging in camouflage-net detection. Full article

Synthetic Aperture Radar (SAR) backscatter serves as a key tool for tracking surface water dynamics; however, single-source data dependencies introduce systematic bias tied to the specific physical limitations of the signal. A primary challenge in SAR analysis is the backscatter ambiguity created by ‘water look-alike’ surfaces, which frequently result in false-positive water detections. We show that integrating interferometric repeat-pass coherence significantly enhances the robustness of hydrological mapping in environments where backscatter is prone to signal ambiguity. Using global-scale C-band Sentinel-1 (S1) VV-polarized one-year mosaics (December 2019 to November 2020), we first analyzed normalized backscatter and coherence signatures across major land cover and land use (LULC) classes. To benchmark the complementary value of these data streams, a tile-based minimum-error thresholding approach was applied to detect permanent water surfaces across five challenging global test sites. This evaluation was conducted without post-processing or masking to isolate the fundamental strengths of each dataset. The results indicate that coherence is an optimal complement to backscatter in arid and bare soil regions, where it vastly outperforms backscatter in mapping inland water surfaces. Crucially, since the spatial overlap of False Positives and False Negatives between datasets is minimal, the inherent complementarity of the datasets is proven here via a logical AND fusion rule, which significantly mitigates commission errors and yields substantial improvements in the aggregated F1-score and IoU performance. Analysis-ready L-band NISAR products could contribute to a more comprehensive approach for operational, large-scale surface water assessments. Full article

Species of the genus Aristolochia are recognized as a rich source of structurally diverse specialized metabolites; however, the volatile chemical composition and biological properties of several Neotropical species remain poorly characterized. In particular, no information is currently available on the essential oil of Aristolochia lingulata Ule ex Pilg., which motivated this chemical, enantioselective, and preliminary biological investigation. The leaf essential oil was analyzed by GC-MS and GC-FID using nonpolar and polar stationary phases, while enantioselective GC-MS was employed to determine the distribution of selected chiral metabolites. Biological activity was evaluated through acetylcholinesterase, butyrylcholinesterase, pancreatic lipase, DPPH, and ABTS assays. A total of 57 constituents were identified and quantified, accounting for 93.5% and 91.3% of the oil on the two stationary phases. Sesquiterpene hydrocarbons and oxygenated sesquiterpenoids predominated, with dauca-5,8-diene, trans-(E)-nerolidol, β-chamigrene, β-cyclocitral, limonene, δ-amorphene, τ-muurolol, and manool among the main constituents. The oil showed moderate acetylcholinesterase inhibition (IC₅₀ = 79.8 ± 0.3 µg/mL), whereas weaker inhibition was observed against butyrylcholinesterase (IC₅₀ = 176.1 ± 3.3 µg/mL) and pancreatic lipase (IC₅₀ = 190.8 ± 9.4 µg/mL). Radical scavenging activity was also weak in the DPPH and ABTS assays (SC₅₀ = 849.7 ± 7.4 and 338.0 ± 3.9 µg/mL, respectively). Overall, this study provides the first characterization of the essential oil of A. lingulata, revealing a distinctive sesquiterpene-rich volatile profile and moderate enzyme-inhibitory activity. These findings expand the phytochemical knowledge of Neotropical Aristolochia species and provide a basis for further investigation of their bioactive constituents, mechanisms of action, and toxicological safety. Full article