Search Results (11,404)

Developing green water disinfection technology has been attracting much attention all over the world. In this work, a WO₃/BiOBr@Si composite was obtained through the solvothermal process, which exhibited denser and fuller intersecting petal-like spheres (1–3 μm in diameter) and retained its 3D sheet-like pore structure. The optical and electrochemical analysis demonstrated that the doped Si showed insignificant improvement in UV-Vis light absorption but greatly promoted the electron-hole separation efficiency and charge transfer capability on the surface of the catalyst at a 4.6 wt% Si doping dosage, resulting in an excellent performance in the inactivation of Escherichia coli (E. coli) under the irradiation of visible light. Under the optimal conditions (0.5 g/L of WO₃/BiOBr@Si dosage, 10⁷ CFU mL⁻¹ of E. coli concertation, and 30 min of treating time), the largest log value decline (6.6) occurred with WO₃/BiOBr@1.0Si, which was 3.3 and 1.8 times larger than those of BiOBr (2.0) and WO₃/BiOBr (3.7). According to the TEM, SEM, EDS, XRD, FTIR, and XPS analyses, in the photocatalytic system, the hole (h⁺) and •OH were the main species for inactivating E. coli cells. These oxidizing species could attack the components on the surface of cells (such as the hydroxyl, carbonyl, ester, and amide groups of polysaccharides (PS) and proteins (PT)), resulting in the inactivation and destruction of the cell membranes and leakage of intracellular substances. The findings will provide a significant guide for developing an efficient catalyst for the green water disinfection process. Full article

The time evolution of nanoscale structure formation on the surface of CdI₂ crystals grown both from the melt and from the gas phase is investigated. Atomic force microscopy was used to show that, already at the initial stages of exposure to air at room temperature, island-shaped nanostructures form, which subsequently aggregate into nanoclusters as the exposure time increases. Similar nanostructures, including nanopores and nanoclusters, are observed for CdI₂ crystals grown from the gas phase after prolonged exposure to air. Photoluminescence spectroscopy indicates that the formed nanoclusters are consistent with the presence of cadmium hydroxide (Cd(OH)₂) and cadmium oxide (CdO). The formation of nanostructures determines the time evolution of the low-temperature luminescence spectra of CdI₂ crystals. Additional bands with maxima at 1.87 eV and long-wavelength luminescence in the region with a maximum at 1.68 eV appear in the spectral structure. These results highlight the close relationship between surface structural evolution and the time-dependent optical properties of CdI₂. Full article

Background/Objectives: This study evaluated the effects of at-home bleaching on color stability (ΔE) and surface roughness (Ra) of a single-shade nanohybrid composite, an ORMOCER-based composite, and a conventional nanohybrid resin composite, acknowledging that bleaching represents only one of several clinical ageing challenges. Methods: One hundred and five extracted, non-carious human molars received standardized Class I restorations and were randomly allocated to five groups (n = 21): an ORMOCER-based composite (Admira Fusion), a single-shade composite (Omnichroma), Omnichroma bonded with an alternative universal adhesive, and two conventional nanohybrid composites (Filtek Supreme Ultra and Harmonize). Baseline and experimental color (CIELAB, ΔE) were measured with a spectrophotometer, and surface roughness (Ra) was measured using a 3D optical profilometer. Specimens underwent five bleaching cycles using 22% carbamide peroxide, with each cycle consisting of 8 h of bleaching followed by 16 h of storage in artificial saliva at 37 °C. Measurements were taken at baseline and after each cycle. The data were analyzed using a repeated-measures ANOVA, with bleaching cycle as the within-subject factor, the effect sizes reported as partial eta-squared (ηp²), and the statistical significance set at α = 0.05. Results: All restorative materials exhibited progressive color change with repeated bleaching, and ΔE values exceeded established clinical acceptability thresholds across materials. The extent of color change varied among materials. None of the evaluated materials maintained clinically acceptable color stability following repeated bleaching cycles. The single-shade composite (Omnichroma) demonstrated the greatest magnitude of color change, particularly when bonded with Scotchbond Universal Bond. Admira Fusion and Filtek Supreme Ultra had lower ΔE values but still exceeded acceptability thresholds. Surface roughness generally decreased following bleaching, with statistically significant reductions in Ra observed for multiple materials. Admira Fusion and Omnichroma bonded with Tokuyama Universal Bond showed minimal surface alteration. Conclusions: All restorative materials demonstrated clinically unacceptable color changes following bleaching, indicating limited esthetic stability under bleaching conditions. ORMOCER-based composites showed comparatively greater resistance to surface roughness alterations. Full article

Numerical simulations of (1) two aerosol types such as organic carbon (i.e., spherical) and dust (i.e., non-spherical) particles, and (2) their mixtures are carried out. Optical and microphysical parameters of these aerosols in our simulations are provided by MERRA-2 (Modern-Era Retrospective Analysis for Research and Applications, version 2). The inversion routine is performed with TiARA (Tikhonov Advanced Regularization Algorithm) using the Lorenz–Mie (i.e., spherical) light-scattering model in unsupervised and automated, i.e., autonomous mode. The results of our numerical simulations show that the accuracy of the inversion results for the aerosol mixtures from synthetic optical data perturbed by ±10% random error is comparable to the accuracy observed for the inversion results of the “pure” spherical particles. In particular, the retrieval uncertainties of effective radius, and number, surface-area, and volume concentrations of these mixtures are ±30%, ±10%, between –50% and +100% and ±30%, respectively. However, we need to apply a modified version of the gradient correlation method (GCM) to stabilize the inversion results. The results of this study will form the baseline for future work, where we plan to apply TiARA to optical data products obtained from real lidar observations in the framework of the SCC (Single Calculus Chain) of EARLINET (European Aerosol Research Lidar Network). Full article

Liver cancer continues to be a predominant cause of cancer-related mortality globally, primarily attributable to late diagnosis and a scarcity of dependable biomarkers for early identification. Raman spectroscopy has emerged as a valuable analytical instrument for liver cancer detection, providing rapid, label-free, and non-destructive molecular profiling of biological specimens. Raman-based methodologies can discern malignant from non-malignant conditions by analyzing small biochemical alterations in biofluids, including blood, urine, and exosomes, as well as in liver tissue, yielding unique spectrum fingerprints. Progress in chemometric analysis, including machine learning models and multivariate statistical methods, has significantly improved the diagnostic precision of Raman spectroscopy, attaining elevated sensitivity and specificity across numerous studies. Furthermore, the integration of complementary techniques, such as surface-enhanced Raman spectroscopy (SERS) and Raman optical activity (ROA) has broadened its prospects for clinical application. This review article elucidates the contemporary applications of Raman spectroscopy in the diagnosis of liver cancer, presents pivotal findings across various sample types, and examines the challenges and future prospects of building Raman-based platforms as dependable diagnostic instruments in oncology. Full article

This work presents a signal processing and reconstruction system developed for a flexible optical pressure 2D mapping sensor. The sensor consists of a two-dimensional grid of polyurethane optical fibers (PU-OFs) embedded in polydimethylsiloxane (PDMS), which acts as the input device for acquiring light intensity changes caused by external surface-applied pressure. In this study, we propose a system to process these signals through an inverse model based on the Moore–Penrose pseudoinverse for spatial localization, along with a point-specific pressure estimation model to infer the magnitude of the applied force, which is then used to generate quantitative pressure maps. Experimental results show the system’s overall performance, robustness, and repeatability across multiple pressure levels and locations. In most cases, localization errors remain below 5 mm, while pressure estimation errors are around 5 mmHg when the pressure is correctly localized. Performance metrics, such as recall, specificity, and precision, support the system’s ability to detect, localize, and reconstruct pressure events with consistent reliability. These results establish the viability of the proposed methodology for potential integration into low-cost and flexible optical fiber-based 2D pressure monitoring systems for biomedical applications. Full article

A novel low-cost poly(propylene carbonate-co-epichlorohydrin) (PPC-ECH) with mechanical properties similar to those of poly (butylene adipate-co-terephthalate) (PBAT) was developed and incorporated into a poly(propylene carbonate-co-phthalate) (PPC-P) matrix. Meanwhile, 4, 4’-diphenylmethane diisocyanate (MDI) was employed as a reactive compatibilizer and mixed with PPC-P and PPC-ECH to create a variety of PPC-P/PPC-ECH/MDI blends. The effects of PPC-ECH and MDI content on the mechanical, optical, thermal, morphological, and gas barrier properties of the blends were systematically investigated. Results demonstrated that MDI reacts with both PPC-P and PPC-ECH, forming a chemically bonded interface that significantly improves their compatibility. Notably, when 2 phr of MDI was incorporated, the elongation at break of the PPC-P/PPC-ECH/2MDI blend increased dramatically from 71% to 502%, while maintaining good tensile strength (~23 MPa) and light transmittance (~80%). To further enhance the gas barrier performance, a high-oxygen-barrier poly(vinyl alcohol) (PVA)/tannic acid (TA) complex coating was applied to the surface of the PPC-P/PPC-ECH/2MDI film. This coating synergistically leveraged the abundant hydroxyl groups in PVA and TA to form a dense hydrogen-bonded network, reducing oxygen permeability to an ultra-low value of 0.1 cm³·mm/(m²·day). This outstanding performance highlights the strong potential of PPC-P/PPC-ECH-based films for advanced packaging applications. Full article

Black crusts are multilayered alteration products that develop on historic masonry exposed to urban pollution. This study investigates the west enclosure wall of the XVII^th-century Golia Monastery in Iași, Romania—located along a busy traffic corridor—and presents multi-analytical results on two lime-based mortar fragments exhibiting well-developed blackened surface layers. Both the exposed (blackened) finishes and protected verso areas were analyzed using portable X-ray fluorescence (pXRF), scanning electron microscopy with energy-dispersive X-ray analysis (SEM–EDX), micro-FTIR spectroscopy, X-ray diffraction (XRD), CIE Lab colorimetry and optical microscopy (OM). The data reveal gypsum-rich surface layers enriched in traffic-derived particles, including metal oxides and soot, with marked contrasts relative to the minimally altered verso. Handheld XRF and SEM–EDX indicate elevated sulfur and associated traffic-related elements within porous gypsum matrices, while FTIR and XRD consistently identify calcium sulfate as the dominant secondary phase. Colorimetric measurements additionally document pronounced lightness loss and visible darkening on exposed surfaces. These results demonstrate the onset of directional sulfation and black crust formation on mortars under urban pollution pressure and establish an integrated analytical protocol for diagnosing black crusts on historic lime mortars in urban heritage settings. Full article

Three-dimensional (3D) cultured cells can mimic the in vivo tumor microenvironment more accurately than conventional monolayer cultures. Therefore, they are essential in cancer research and drug discovery. However, high-sensitivity fluorescence imaging of 3D spheroids remains challenging owing to their limited contact with the observation surface and the low penetration depth of total internal reflection fluorescence microscopy (TIRFM). In this study, we developed a microfluidic device equipped with a water-driven balloon actuator that enables the hydrostatic compression of 3D-cultured spheroids. This system gently presses spheroids against a glass surface, significantly enhancing the contact area and improving TIRFM and epifluorescence imaging quality, with more evident improvement observed in TIRFM. Our results show that hydrostatic compression markedly enhances optical accessibility in spheroids while preserving cell viability and structural integrity. The method is designed to complement volumetric imaging techniques, including confocal and light-sheet microscopy, by enabling high-contrast visualization of cell–surface molecular dynamics. Although the current system focuses on surface accessibility, future studies will incorporate rotational mechanisms and automated pressure control to facilitate multi-angle, high-throughput imaging. This platform offers a promising strategy for the dynamic observation of cell–surface interactions in living 3D systems. Full article

The topographic shadow effect can cause surface reflectance distortions in the shadow areas of remote sensing images, particularly in complex mountainous areas. In this study, based on the difference in solar radiation received at the surface of sunlit and shadow areas, we introduced the shadow intensity, vegetation index, and band adjustment factors, and proposed a topographic shadow effect correction (TSEC) method. The method was then tested using eight Landsat 8 OLI scenes under different illumination conditions from two different regions. The results indicate that TSEC effectively corrected the topographic shadow effect. The corrected images exhibited good visual quality without obvious shadow pixels. Importantly, TSEC retained spectral information in sunlit areas while correcting spectral distortion in shadow areas, resulting in strong agreement between spectral curves of shady and sunny slopes. The method demonstrated high stability in normalized difference vegetation index (NDVI) correction, as the difference in NDVI before and after correction was less than 0.07 for the four scenes within the Changjiang study area. Moreover, the TSEC corrected the enhanced vegetation index (EVI) effectively, reducing an initial EVI difference of over 0.35 between the shady and sunny slopes to a maximum of 0.074 for the four scenes within the Wuyi Mountain study area. Relative to four established topographic correction models, the proposed method suppresses the over-correction phenomena typical of self-shadows and minimizes under-correction in cast shadows, resulting in stable overall correction results with few outliers. The TSEC provides a simple and effective method to correct the distorted reflectance in shadow areas using only image and DEM data, which can be adapted to complex mountainous areas and for images with different illumination conditions. Full article

Lignin from Phaleria macrocarpa (Mahkota Dewa) fruit, a bioactive-rich cultivated medicinal biomass, was employed as a renewable precursor for lignin quantum dots (LQDs). A simple, aqueous, catalyst-free two-step route (lignin to lignin nanoparticles to LQDs) is demonstrated, enabling the valorization of non-food lignin into photoluminescent nanomaterials. The resulting LQDs were predominantly amorphous with short-range graphitic ordering and a narrow particle size distribution (3–5 nm). Structural and chemical analyses indicated a partially graphitized carbon framework enriched with oxygenated surface functionalities, which is consistent with their bright blue–green emission (λ_em of 490 nm; average fluorescence lifetime of 4.51 ns). Hydrothermal carbonization induced a blue shift in the UV–Vis absorption profile, resulting in a main band at 288 nm with a shoulder at 312 nm. The LQDs exhibited high cytocompatibility toward L929 mouse fibroblasts (93.1 ± 6.5% viability at 24 h) and were readily internalized by cells, facilitating green fluorescence live-cell imaging as a proof-of-concept. Antibacterial activity was observed against both Gram-positive and Gram-negative strains, supporting dual biofunctional performance. Overall, this study established a green and scalable route for converting P. macrocarpa fruit lignin into multifunctional LQDs, with potential applications in circular-bioeconomy such as antimicrobial/active coatings and optical sensing in agro-industrial contexts. Full article

Photothermal therapy (PTT) is an emerging minimally invasive approach for cancer treatment that relies on photothermal agents capable of efficiently converting near-infrared (NIR) light into localized heat. In this work, silica–gold nanostructures (SGNs) were synthesized and systematically evaluated to investigate how silica core size influences the photothermal response of the SGNs and optimize their performance as a photothermal agent. SGNs were synthesized with silica cores ranging from 54 to 244 nm in diameter and coated with gold nanoparticles of 4–10 nm in size, enabling controlled tuning of their localized surface plasmon resonance within the NIR region. The morphology and composition were characterized by SEM, TEM, and EDS; optical properties were analyzed by UV-Vis spectroscopy. The SGNs photothermal response low-power laser irradiation at 852 nm and 1310 nm and temperature changes were monitored using a thermographic camera. A maximum temperature increase of 7.1 °C was observed for SGNs with a silica core diameter of approximately 77 nm under the 852 nm laser irradiation. Numerical simulations of the absorption efficiency showed good agreement with experimental UV–Vis spectra and thermal measurements, revealing a size-dependent shift of the absorption toward longer wavelengths for larger nanostructures. These results demonstrate that the photothermal response of silica–gold nanostructures can be rationally tuned through the control of core size and gold growth parameters, providing a framework for the design of wavelength-matched photothermal agents for PTT applications. Full article

Waste oyster shell powder (OP) and calcined oyster shell powder (COP) were used as bio-fillers in asphalt mastics. Limestone powder (LP) served as the control. This study employed rheological theory to quantify filler–asphalt interactions. Dynamic shear rheometry (DSR), Black diagrams, and master curves were analyzed to determine critical volume fraction (φ_crit), interaction parameter (C), and complex viscosity increment (∆η*). Results indicate that OP mastics exhibit the lowest φ_crit (0.510) and highest C value (1.133), demonstrating the strongest interfacial interaction. COP shows intermediate interaction strength (φ_crit = 0.542), yet both OP and COP outperform LP (φ_crit = 0.617) in high-temperature deformation resistance within the 0.23–0.53 filler volume fraction range, evidenced by superior complex shear modulus (G*) master curves and pronounced ∆η* increases. Grey relational analysis identifies specific surface area and CaCO₃ content as governing factors. Optical microscopy and FTIR confirm that filler–asphalt interactions are dominated by physical adsorption without chemical bond formation. These findings elucidate the performance advantages of both raw and calcined oyster shell powders and provide a theoretical basis for their application as sustainable high-performance bio-fillers in asphalt pavements. Full article

This research examines how atmospheric plasma spraying torch power and coating thickness jointly affect the adhesion strength, microstructure, porosity, and flexural behavior of $A{l}_2{O}_3$ coatings on 100Cr6 steel substrates. Optical microscopy, SEM and EDS mapping, 3D surface-roughness analysis, Vickers hardness testing (HV2) on polished cross-sections, and three-point bending of extracted beams were employed to develop a processing–structure–property map. This multi-technique approach enables the cross-validation of processing–structure–property relationships and supports a robust identification of the optimal power–thickness condition by jointly considering porosity (densification), adhesion strength, flexural response and failure mode. All conditions resulted in an average surface roughness Ra of approximately 1.0 µm. Increasing torch power to 45 kW generally reduced cross-sectional porosity, except at 500 µm, where globular pores appeared. Hardness (HV2) increased with power and peaked at the intermediate thickness (500 µm); adhesion up to 63 MPa was recorded for the 300 µm/45 kW coating. Flexural strength was highest at 500 µm and was consistently greater at 45 kW than at 39 kW. Fractography showed a shift in failure mode from interface-driven delamination at 39 kW to more cohesive, tortuous intra-coating cracks at 45 kW, aligned with improved splat bonding and crack-path deflection. An intermediate thickness of 500 µm deposited at 45 kW is thus identified as an optimal condition to balance densification and crack-path tortuosity, leading to enhanced hardness and flexural performance. Full article

The inherently high-voltage-length product (V_πL) of thin-film lithium niobate (TFLN) modulators in the O-, C-, and L-telecom bands restricts further scaling of photonic integrated circuits’ bandwidth density, driving their migration toward shorter operating wavelengths. Nevertheless, the corresponding grating couplers, as critical optical input/outputs (optical I/Os) interfaces, remain largely undeveloped. Here, we demonstrate an 850 nm TFLN grating coupler designed based on topological unidirectional guided resonance (UGR). By breaking C₂ symmetry of the unit cell and precisely tailoring its geometry, we achieve unidirectional upward radiation with a 63.7 dB up/down intensity ratio. Subsequent apodization of groove widths and periods enables precise control of the electrical field distribution in both real and momentum spaces. This yields a vertical-cavity surface-emitting laser (VCSEL)-matched, highly fabrication-tolerant TFLN grating coupler that attains, to the best of our knowledge, the highest simulated coupling efficiency of −0.6 dB without mirrors or hybrid materials. This work delivers a high-efficiency, layout-flexible, and complementary metal oxide semiconductor (CMOS)-compatible optical I/Os solution for short-wavelength TFLN modulators with low V_πL. It offers substantial engineering value and broad applicability for on-chip light source integration and high-bandwidth-density short-reach optical interconnects. Full article