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29 pages, 686 KiB  
Review
Targeted Screening Strategies for Head and Neck Cancer: A Global Review of Evidence, Technologies, and Cost-Effectiveness
by Orlando Guntinas-Lichius, Claudio Bücking, Sweet Ping Ng, Fernando López, Juan Pablo Rodrigo, Karthik N. Rao, Andrés Coca Pelaz, Luiz P. Kowalski, Cesare Piazza, Alessandra Rinaldo and Alfio Ferlito
Diagnostics 2025, 15(16), 2095; https://doi.org/10.3390/diagnostics15162095 - 20 Aug 2025
Abstract
Head and neck cancer (HNC) is the seventh most common cancer worldwide, with rising incidence particularly in oropharyngeal cancer subsites. Despite well-known risk factors, such as tobacco and alcohol consumption as well as human papillomavirus (HPV) infection, most HNCs are diagnosed at an [...] Read more.
Head and neck cancer (HNC) is the seventh most common cancer worldwide, with rising incidence particularly in oropharyngeal cancer subsites. Despite well-known risk factors, such as tobacco and alcohol consumption as well as human papillomavirus (HPV) infection, most HNCs are diagnosed at an advanced stage, resulting in poor prognosis. Early detection and screening are critical, especially in high-risk populations. Nevertheless, there is a lack of guidelines for a stratified HNC screening. A systematic literature review was conducted following PRISMA guidelines, using PubMed and ScienceDirect databases up to 30 June 2025. Search terms included “screening”, “early diagnosis”, and specific HNC subsites. A total of 199 records were screened, and 160 studies were included based on relevance and scientific rigor. The review concentrates on contemporary screening modalities, stratification of high-risk cohorts, emerging technologies, and cost-effectiveness evidence. Visual inspection and panendoscopy remain the standard tools for HNC screening, but have limited effectiveness and cost-efficiency. Opportunistic screening in high-risk individuals, especially in regions with high HNC prevalence, has shown benefits. Liquid biopsy techniques targeting HPV- and Epstein-Barr virus-related HNC demonstrate high sensitivity for early detection and recurrence monitoring. Novel imaging technologies like narrow-band imaging and Raman spectroscopy show promising diagnostic accuracy but require further validation. Most broad-based screening programs lack cost-effectiveness, while targeted strategies in high-risk groups appear more viable. Screening for HNC should be stratified by individual risk profiles and regional disease prevalence. Emerging technologies, particularly liquid and optical biopsy techniques, offer transformative potential. Future screening strategies must integrate technological advances into tailored, evidence-based protocols to improve early detection and patient outcomes in HNC. Full article
17 pages, 5692 KiB  
Article
Investigating the Influence of Cerium Doping on the Structural, Optical, and Electrical Properties of ZnCexCo2xO4 Zinc Cobaltite Thin Films
by Abdellatif El-Habib, Mohamed Oubakalla, Samir Haloui, Youssef Nejmi, Mohamed El Bouji, Amal Yousfi, Fouad El Mansouri, Abdessamad Aouni, Mustapha Diani and Mohammed Addou
Crystals 2025, 15(8), 742; https://doi.org/10.3390/cryst15080742 (registering DOI) - 20 Aug 2025
Abstract
Cerium-doped zinc cobaltite spinel thin films, ZnCexCo2xO4 (0.00x0.05), were synthesized via spray pyrolysis, and their structural, morphological, optical, and electrical properties were analyzed. X-ray [...] Read more.
Cerium-doped zinc cobaltite spinel thin films, ZnCexCo2xO4 (0.00x0.05), were synthesized via spray pyrolysis, and their structural, morphological, optical, and electrical properties were analyzed. X-ray diffraction (XRD) confirmed a cubic spinel structure with a predominant (311) orientation across all compositions. Raman spectroscopy further verified this phase, revealing four active vibrational modes at 180 cm−1, 470 cm−1, 515 cm−1, and 682 cm−1. Scanning electron microscopy (SEM) indicated a uniform grain distribution, while energy-dispersive X-ray spectroscopy (EDS) confirmed the presence of Ce, Zn, Co, and O. Optical measurements revealed two distinct bandgaps, decreasing from 2.32 eV to 2.20 eV for the lower-energy transition and from 3.38 eV to 3.18 eV for the higher-energy transition. Hall effect measurements confirmed p-type conductivity in all films. Electrical analysis showed a reduction in resistivity, from 280.3 Ω·cm to 15.4 Ω·cm, along with an increase in carrier concentration from 1.15 × 1016 cm−3 to 8.15 × 1017 cm−3 with higher Ce content. These results demonstrate that spray pyrolysis is a cost-effective and scalable method for producing Ce-doped ZnCo2O4 thin films with tunable properties, making them suitable for electronic and optoelectronic applications. Full article
(This article belongs to the Special Issue Advances in Thin-Film Materials and Their Applications)
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20 pages, 1921 KiB  
Article
Photoactive Hydrogels as Materials for Biological Applications: Preparation of Thermally Stable Photoactive Films
by Oscar G. Marambio, Lidia Álvarez, Héctor Díaz-Chamorro, Julio Sánchez, Rudy Martin-Trasancos, Christian Erick Palavecino and Guadalupe del C. Pizarro
Gels 2025, 11(8), 663; https://doi.org/10.3390/gels11080663 - 20 Aug 2025
Abstract
Hydrogel materials have become an efficient, bioactive, and multifunctional alternative with great potential for biomedical applications. In this work, photoactive films were successfully designed for optical processing, and their photoactivity was tested in photodynamic therapy (PDT), such as antimicrobial patches. The stimulus-response hydrogel [...] Read more.
Hydrogel materials have become an efficient, bioactive, and multifunctional alternative with great potential for biomedical applications. In this work, photoactive films were successfully designed for optical processing, and their photoactivity was tested in photodynamic therapy (PDT), such as antimicrobial patches. The stimulus-response hydrogel films are made of a hydrophilic polymer based on vinyl monomers, specifically 2-hydroxyethyl methacrylate (HEMA) and acrylamide (AAm), in a 1:1 molar ratio, along with the photochromic agent, 3,3-dimethylindolin-6′-nitrobenzoespiropirano (BSP), and a crosslinking agent, N,N’-methylenebisacrylamide (MBA). These hydrogel films were successfully created using the photoinitiator 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone (IRGACURE 2959), MBA, and BSP in different concentrations (0.1, 0.3, and 0.5 mol%), which were later tested in photodynamic therapy (PDT) with the photosensitizer Ru(bpy)22+ against Staphylococcus aureus. The results showed that, while free Ru(bpy)22+ needed concentrations of 4–8 µg/mL to eliminate methicillin-sensitive (MSSA) strains, only partial inactivation was achieved for methicillin-resistant (MRSA) strains. The addition of the hydrogel films with BSP improved their effectiveness, lowering the minimum inhibitory concentration (MIC) to 2 µg/mL to fully inactivate MSSA and MRSA strains. These findings demonstrate that the combined use of hydrogel films containing BSP and Ru(bpy)22+ within a hydrogel matrix not only boosts antimicrobial activity but also highlights the potential of these photoactive films as innovative photosensitive antimicrobial coatings. This synergistic effect of BSP and Ru(bpy)22+ indicates that these materials are promising candidates for next-generation antimicrobial coatings and creative photosensitive materials. Full article
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13 pages, 2819 KiB  
Article
Stormwater in the Desert: Unveiling Metal Pollutants in Climate-Intensified Flooding in the United Arab Emirates
by Lara Dronjak, Sofian Kanan, Tarig Ali, Md Maruf Mortula, Areej Mohammed, Jonathan Navarro Ramos, Diana S. Aga and Fatin Samara
Water 2025, 17(16), 2457; https://doi.org/10.3390/w17162457 - 19 Aug 2025
Abstract
This study investigated the concentrations of metals in stormwater runoff collected during two extreme flooding events on the American University of Sharjah (AUS) campus in the United Arab Emirates (UAE). Given the increasing frequency of intense rainfall in arid regions, stormwater contamination represents [...] Read more.
This study investigated the concentrations of metals in stormwater runoff collected during two extreme flooding events on the American University of Sharjah (AUS) campus in the United Arab Emirates (UAE). Given the increasing frequency of intense rainfall in arid regions, stormwater contamination represents a growing environmental and public health concern. Stormwater samples were analyzed using inductively coupled plasma optical emission spectrometry (ICP-OES) to quantify metal concentrations. The results showed that iron (0.049–2.080 mg/L), aluminum (0.097–2.020 mg/L), and potassium (0.614–3.860 mg/L) were the most abundant metals detected. Lower concentrations were observed for manganese (0.000–0.058 mg/L), barium (0.000–0.073 mg/L), chromium (0.000–0.013 mg/L), nickel (0.000–0.038 mg/L), and vanadium (0.000–0.004 mg/L). These findings underscore the critical need for effective stormwater management in arid regions, where climate change is expected to increase the frequency and intensity of extreme weather events. Improved drainage systems and long-term monitoring are essential to mitigate the environmental and public health risks posed by stormwater contamination in rapidly urbanizing areas. Full article
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14 pages, 9284 KiB  
Article
A Rapid and Low-Cost Synthesis of ZSM-5 Single Crystals: The Inhibitory Effect of NH4F on Twinning
by Juan Du, Xiang Wan, Caixiong Song, Kangsheng Wu, Wenbing Yang, Beiye Liu, Qi Yang, Jingjing Fang and Ayesha Razzaq
Inorganics 2025, 13(8), 272; https://doi.org/10.3390/inorganics13080272 - 18 Aug 2025
Abstract
Crystal twinning, a common growth phenomenon, can substantially affect material performance in fields such as semiconductors, nonlinear optics, and drug development, yet its elimination during crystallization is challenging. This study presents a method for the controlled synthesis of ZSM-5 zeolite as either single [...] Read more.
Crystal twinning, a common growth phenomenon, can substantially affect material performance in fields such as semiconductors, nonlinear optics, and drug development, yet its elimination during crystallization is challenging. This study presents a method for the controlled synthesis of ZSM-5 zeolite as either single crystals or twinned crystals using kaolin as the primary raw material. The method leverages the etching effect of ammonium fluoride (NH4F) on the aluminosilicate structure derived from pre-treated kaolin. By adjusting the concentrations of NH4F and the structure-directing agent tetrapropylammonium bromide (TPABr), pure ZSM-5 single crystals and twinned crystals were selectively synthesized. Conventionally, NH4F is employed to introduce defects into zeolite structures. In contrast, this work demonstrates its utility in controlling crystal habit. The synthesis utilizes kaolin, an abundant and low-cost aluminosilicate mineral, to provide the entire aluminum source and a portion of the silicon source, offering an economical alternative to expensive precursors like aluminum isopropoxide. The resulting single and twinned crystals exhibited high crystallinity, demonstrating the viability of using natural minerals to produce high-quality zeolites. The physical and chemical properties of the kaolin-derived ZSM-5 were characterized and compared to those of ZSM-5 synthesized from conventional chemical reagents. A growth mechanism for the formation of single and twinned crystals is also proposed. Full article
(This article belongs to the Section Inorganic Solid-State Chemistry)
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21 pages, 4146 KiB  
Article
Analysis of Spatiotemporal Distribution Trends of Aerosol Optical Depth and Meteorological Influences in Gansu Province, Northwest China
by Fangfang Huang, Chongshui Gong, Weiqiang Ma, Hao Liu, Binbin Zhong, Cuiwen Jing, Jie Fu, Chunyan Zhang and Xinghua Zhang
Remote Sens. 2025, 17(16), 2874; https://doi.org/10.3390/rs17162874 - 18 Aug 2025
Viewed by 2
Abstract
Atmospheric pollution constitutes one of the key environmental challenges hindering Atmospheric pollution is a key environmental challenge constraining the sustainable development of Gansu Province’s land-based Belt and Road corridor and its regional ecological barrier function. The spatiotemporal heterogeneity of aerosol optical depth (AOD) [...] Read more.
Atmospheric pollution constitutes one of the key environmental challenges hindering Atmospheric pollution is a key environmental challenge constraining the sustainable development of Gansu Province’s land-based Belt and Road corridor and its regional ecological barrier function. The spatiotemporal heterogeneity of aerosol optical depth (AOD) profoundly impacts regional environmental quality. Based on MODIS AOD, NCEP reanalysis, and emission data, this study employed trend analysis (Mann–Kendall test) and attribution analysis (multiple linear regression combined with LMG and Spearman correlation) to investigate the spatiotemporal evolution of AOD over Gansu Province during 2009–2019 and its meteorological and emission drivers. Key findings include the following: (1) AOD exhibited significant spatial heterogeneity, with high values concentrated in the Hexi Corridor and central regions; monthly variation showed a unimodal pattern (peak value of 0.293 in April); and AOD generally declined slowly province-wide during 2009–2019 (52.8% of the area showed significant decreases). (2) Following the implementation of the Air Pollution Prevention and Control Action Plan in 2013 (2014–2019), AOD trends stabilized or declined in 99.8% of the area, indicating significant improvement. (3) Meteorological influences displayed distinct regional-seasonal specificity—the Hexi Corridor (arid zone) was characterized by strong negative correlations with relative humidity (RH2) and wind speed (WS) year-round, and positive correlations with temperature (T2) in spring but negative in summer in the north; the Hedong region (industrial zone) featured strong positive correlations with planetary boundary layer height (PBLH) in summer (r > 0.6) and with T2 in spring/summer; and the Gannan Plateau (alpine zone) showed positive WS correlations in spring and weak positive RH2 correlations in spring/autumn, highlighting the decisive regulatory role of underlying surface properties. (4) Emission factors (PM2.5, SO42, NO3, NH4+, OM, and BC) dominated (>50% relative contribution) in 80% of seasonal scenarios, prevailing in most regions (Hexi: 71–95% year-round; Hedong: 68–80% year-round; and Gannan: 69–72% in spring/summer). Key components included BC (contributing > 30% in 11 seasons, e.g., 52.5% in Hedong summer), NO3 + NH4+ (>57% in Hexi summer/autumn), and OM (20.3% in Gannan summer, 19.0% province-wide spring). Meteorological factors were the primary driver exclusively in Gannan winter (82%, T2-dominated) and province-wide summer (67%, RH2 + WS-dominated). In conclusion, Gansu’s AOD evolution is co-driven by emission factors (dominant province-wide) and meteorological factors (regionally and seasonally specific). Post-2013 environmental policies effectively promoted regional air quality improvement, providing a scientific basis for differentiated aerosol pollution control in arid, industrial, and alpine zones. Full article
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10 pages, 1814 KiB  
Article
Impact of Surface Preparation on the Quantification of Diffusible Hydrogen Content in Aluminum Alloys
by Mehrdad Hoseinpoor, Nikola Macháčková, Terezie Košová Altnerová, Sandrine Zanna, Darja Rudomilova and Tomáš Prošek
Metals 2025, 15(8), 913; https://doi.org/10.3390/met15080913 - 17 Aug 2025
Viewed by 164
Abstract
The impact of final surface preparation immediately prior to hydrogen content measurements in aluminum alloy samples was investigated using thermal desorption analysis (TDA). Samples ground in water showed an apparent hydrogen signal. Glow-discharge optical emission spectroscopy (GDOES) confirmed that the analyzed hydrogen originated [...] Read more.
The impact of final surface preparation immediately prior to hydrogen content measurements in aluminum alloy samples was investigated using thermal desorption analysis (TDA). Samples ground in water showed an apparent hydrogen signal. Glow-discharge optical emission spectroscopy (GDOES) confirmed that the analyzed hydrogen originated from the subsurface layer. X-ray photoelectron spectroscopy (XPS) revealed the presence of a thin aluminum oxide/hydroxide layer on the surface. Formation of these compounds indicates that hydrogen was introduced into the material by the reaction of oxide-free aluminum with water molecules during the grinding, followed by its entrapment at near-surface interstitial lattice sites. Chemical pickling in concentrated nitric acid and combined grinding, chemical pickling, and electrochemical polishing approaches are proposed as proper surface-preparation techniques for samples without and with adherent corrosion products, respectively. Full article
(This article belongs to the Special Issue Light Alloy and Its Application (2nd Edition))
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50 pages, 5154 KiB  
Review
Applications of Tailored Mesoporous Silicate Nanomaterials in Regenerative Medicine and Theranostics
by Jean Fotie
Int. J. Mol. Sci. 2025, 26(16), 7918; https://doi.org/10.3390/ijms26167918 - 16 Aug 2025
Viewed by 332
Abstract
Tailored mesoporous silicate nanomaterials have attracted significant interest due to their exceptional surface properties, including high interfacial toughness, tunable thickness, customizable topology, optical transparency, and adjustable hydrophobicity. These characteristics enable them to exhibit a wide range of functional behaviors, such as antibacterial, anti-fouling, [...] Read more.
Tailored mesoporous silicate nanomaterials have attracted significant interest due to their exceptional surface properties, including high interfacial toughness, tunable thickness, customizable topology, optical transparency, and adjustable hydrophobicity. These characteristics enable them to exhibit a wide range of functional behaviors, such as antibacterial, anti-fouling, anti-fogging, lubricating, and abrasion-resistant properties, to name just a few. With recent advances in surface-modified nanosystems for bioengineering and biomedical applications, silica-based nanomaterials have emerged as promising candidates owing to their ease of surface functionalization, bioactivity, biocompatibility, biodegradability, and bioavailability. Consequently, they have been widely explored in various therapeutic contexts. This review provides a concise and concentrated summary of recent advances and applications of tailored mesoporous silicate nanomaterials in regenerative medicine and theranostics, with the primary focus being on how endogenous or exogenous triggers can be leveraged to achieve selective and precise delivery of various biomolecules and active therapeutics across diverse cellular environments, by harnessing the intrinsic properties of mesoporous silicate nanoparticles. This focus also guided the selection of specific examples provided to highlight their wide range of applications, with the report concluding with some perspectives and remaining challenges. Full article
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19 pages, 3921 KiB  
Article
Online-Coupled Aerosol Effects on Cloud Microphysics and Surface Solar Irradiance in WRF-Solar
by Su Wang, Gang Huang, Tie Dai, Xiang’ao Xia, Letu Husi, Run Ma and Cuina Li
Remote Sens. 2025, 17(16), 2829; https://doi.org/10.3390/rs17162829 - 14 Aug 2025
Viewed by 265
Abstract
The online coupling of aerosols and clouds and its effect on surface global horizontal irradiance (GHI) has not yet been thoroughly investigated in the Weather Research and Forecasting Model with Solar extensions (WRF-Solar), despite its potential significance for solar energy applications. This study [...] Read more.
The online coupling of aerosols and clouds and its effect on surface global horizontal irradiance (GHI) has not yet been thoroughly investigated in the Weather Research and Forecasting Model with Solar extensions (WRF-Solar), despite its potential significance for solar energy applications. This study addresses this critical gap by implementing a computationally efficient, coupled aerosol–cloud scheme and evaluating its impacts on GHI predictability. Simulations with online aerosol–cloud coupling are systematically compared to uncoupled simulations during March 2021, a period marked by two distinct pollution episodes over north China. The online coupling enhances aerosol optical depth (AOD) simulations, increasing the correlation coefficient from 0.19 to 0.51 while reducing the absolute bias from 0.54 to 0.48 and root mean square error from 0.82 to 0.72, compared to uncoupled simulations. Enhanced cloud microphysics (droplet concentration, water path) yields better cloud optical depth estimates, reducing all-sky GHI bias by 14.5% (63.5 W/m2 for the uncoupled scenario and 54.3 W/m2 for the coupled scenario) through improved aerosol–cloud–meteorology interactions. Notably, the simultaneous spatiotemporal improvement of both AOD and GHI suggests enhanced internal consistency in aerosol–cloud–radiation interactions, which is crucial for operational solar irradiance forecasting in pollution-prone regions. The results also highlight the practical value of incorporating online aerosol coupling in solar forecasting models. Full article
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16 pages, 6603 KiB  
Article
Influence of the Molar Mass and Concentration of the Polyvinylpyrrolidone on the Physical–Mechanical Properties of Polylactic Acid for Food Packaging
by Ivan Restrepo, Eliezer Velásquez, María Galotto and Abel Guarda
Polymers 2025, 17(16), 2218; https://doi.org/10.3390/polym17162218 - 14 Aug 2025
Viewed by 223
Abstract
Improving the end-of-life performance of polylactic acid (PLA) for food packaging requires strategies that enhance biodegradability, solubility, and dispersibility without compromising essential material properties. PLA-based films were produced by melt extrusion using polyvinylpyrrolidone (PVP) as a hydrophilic modifier, aiming to enhance the water [...] Read more.
Improving the end-of-life performance of polylactic acid (PLA) for food packaging requires strategies that enhance biodegradability, solubility, and dispersibility without compromising essential material properties. PLA-based films were produced by melt extrusion using polyvinylpyrrolidone (PVP) as a hydrophilic modifier, aiming to enhance the water uptake and affinity of PLA, which may potentially lead to faster environmental degradation. Two PVPs with distinct molar masses at varying concentrations were used to investigate their effects on the structural, thermal, mechanical, optical, and barrier behavior of the films. Thermal analysis revealed a slight depression in glass transition temperature, more evident in blends with low-molecular-weight PVP10, indicating increased chain mobility and partial miscibility. A two-step degradation process with extended thermal decomposition profiles was observed upon the inclusion of PVP. SEM and ATR-FTIR analyses confirmed enhanced dispersion and non-covalent interactions in PVP10-based blends, in contrast to the pronounced phase separation and micro-voids observed in PVP40-based systems. Mechanically, films containing 5 and 10 wt.% of PVP10 retained tensile strength and stiffness, whereas PVP40 led to embrittlement. Optical properties were modified by increasing the PVP content, resulting in greater opacity and color differences, which potentially offer benefits for light-sensitive packaging. Altogether, PLA films containing 5 and 10 wt.% of PVP10 demonstrated the most favorable balance between water affinity-oriented design and packaging-relevant performance. Full article
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33 pages, 3734 KiB  
Article
Preparation and Performance Characterization of Melamine-Formaldehyde-Microencapsulated Waterborne Topcoat–Brass Powder–Waterborne Acrylic Coating
by Wenjing Chang, Yan Han, Xiaoxing Yan and Jun Li
Coatings 2025, 15(8), 951; https://doi.org/10.3390/coatings15080951 - 14 Aug 2025
Viewed by 314
Abstract
A novel self-healing brass powder/waterborne acrylic decorative coating for wooden substrates was developed, in which γ-methacryloxypropyltrimethoxysilane (KH570)-modified brass powder (with a coupling agent concentration of 6% and reaction solution pH of 5) was employed as the filler, and melamine-formaldehyde (MF) resin-encapsulated water-based paint [...] Read more.
A novel self-healing brass powder/waterborne acrylic decorative coating for wooden substrates was developed, in which γ-methacryloxypropyltrimethoxysilane (KH570)-modified brass powder (with a coupling agent concentration of 6% and reaction solution pH of 5) was employed as the filler, and melamine-formaldehyde (MF) resin-encapsulated water-based paint microcapsules were utilized as the healing agent. The brass powder content and the core–wall ratio of the topcoat microcapsules were identified as the predominant factors affecting both the optical and mechanical properties of the self-healing brass powder/waterborne acrylic coating on Basswood surfaces. Therefore, the brass powder content was selected as the primary influencing factor. With concentration gradients of 0.5%, 1%, 3%, 5%, 7%, 9%, and 10%, and under constant conditions of 3% microcapsule content and room temperature curing, the effect of brass powder content on the properties of self-healing microcapsule coatings with different core–wall ratios was investigated. The waterborne acrylic wood coating containing 3% brass powder and 3% microcapsules with a core–wall ratio of 0.58:1 exhibited superior overall performance. This optimized formulation not only maintained excellent optical properties but also significantly enhanced mechanical performance, while preserving outstanding aging resistance, liquid resistance, and self-healing capability. The coating demonstrated the following comprehensive performance metrics: a glossiness of 24.0 GU, color difference (ΔE) of 2.13, chromatic aberration (ΔE*) of 13.68, visible light reflectance of 0.5879, dominant wavelength of 587.47 nm, visible light transmittance of 74.33%, pencil hardness of H grade, impact resistance of 2 kg·cm, adhesion rating of class 2, surface roughness of 2.600 μm, along with excellent aging resistance and liquid resistance properties, while achieving a self-healing efficiency of 19.62%. The coating also exhibited a smooth and uniform microscopic morphology, with the chemical bonds of both the modified brass powder and microcapsules remaining intact within the coating matrix. Full article
(This article belongs to the Special Issue Novel Microcapsule Technology in Coatings)
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13 pages, 2078 KiB  
Article
Concentric Intensity-Based Adjacent OAM Mode Separation for High-Efficiency Free-Space Optical Spatial Multiplexing
by Ji-Yung Lee, Jiyeon Baek, Junsu Kim, Sujan Rajbhandari, Seung Ryong Park and Hyunchae Chun
Appl. Sci. 2025, 15(16), 8949; https://doi.org/10.3390/app15168949 - 13 Aug 2025
Viewed by 254
Abstract
The rapid growth of data traffic in modern communication networks has led to the development of advanced high-capacity multiplexing methods. Orbital angular momentum (OAM)–based mode division multiplexing (MDM) offers a promising scheme by utilizing the orthogonality of helical phase modes to transmit independent [...] Read more.
The rapid growth of data traffic in modern communication networks has led to the development of advanced high-capacity multiplexing methods. Orbital angular momentum (OAM)–based mode division multiplexing (MDM) offers a promising scheme by utilizing the orthogonality of helical phase modes to transmit independent data streams simultaneously. In this work, we introduce a novel adjacent mode separation method exploiting OAM’s concentric intensity characteristics for free-space optical (FSO) spatial multiplexing. This method enables the detection of each OAM channel based on its distinctive ring-shaped intensity distribution, contrary to the conventional on-axis phase flattening approach. Two spatially multiplexed signals with different modes are separated by aligning its concentric intensity ring with the active area of an avalanche photodiode (APD), effectively suppressing crosstalk from adjacent modes. Experimental measurements demonstrate that our method achieves a bit-error-rate (BER) performance not exceeding the forward error correction (FEC) threshold, 3.8×103, at up to 160 Mbps of data rate, while the conventional detection scheme fails beyond 5 Mbps. The analysis of the eye diagram confirms that our concentric-ring demultiplexing system achieves a high signal-to-noise ratio (SNR) and mode selectivity. These results support the feasibility of the proposed concentric intensity-based mode separation methodology for constructing compact, high-throughput OAM-multiplexed FSO links. Full article
(This article belongs to the Section Electrical, Electronics and Communications Engineering)
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19 pages, 7138 KiB  
Article
Classification Algorithms for Fast Retrieval of Atmospheric Vertical Columns of CO in the Interferogram Domain
by Nejla Ećo, Sébastien Payan and Laurence Croizé
Remote Sens. 2025, 17(16), 2804; https://doi.org/10.3390/rs17162804 - 13 Aug 2025
Viewed by 225
Abstract
Onboard the MetOp satellite series, Infrared Atmospheric Sounding Interferometer (IASI) is a Fourier Transform spectrometer based on the Michelson interferometer. IASI acquires interferograms, which are processed to provide high-resolution atmospheric emission spectra. These spectra enable the derivation of temperature and humidity profiles, among [...] Read more.
Onboard the MetOp satellite series, Infrared Atmospheric Sounding Interferometer (IASI) is a Fourier Transform spectrometer based on the Michelson interferometer. IASI acquires interferograms, which are processed to provide high-resolution atmospheric emission spectra. These spectra enable the derivation of temperature and humidity profiles, among other parameters, with exceptional spectral resolution. In this study, we evaluate a novel, rapid retrieval approach in the interferogram domain, aiming for near-real-time (NRT) analysis of large spectral datasets anticipated from next-generation tropospheric sounders, such as MTG-IRS. The Partially Sampled Interferogram (PSI) method, applied to trace gas retrievals from IASI, has been sparsely explored. However, previous studies suggest its potential for high-accuracy retrievals of specific gases, including CO, CO2, CH4, and N2O at the resolution of a single IASI footprint. This article presents the results of a study based on retrieval in the interferogram domain. Furthermore, the optical pathway differences sensitive to the parameters of interest are studied. Interferograms are generated using a fast Fourier transform on synthetic IASI spectra. Finally, the relationship to the total column of carbon monoxide is explored using three different algorithms—from the most intuitive to a complex neural network approach. These algorithms serve as a proof of concept for interferogram classification and rapid predictions of surface temperature, as well as the abundances of H2O and CO. IASI spectra simulations were performed using the LATMOS Atmospheric Retrieval Algorithm (LARA), a robust and validated radiative transfer model based on least squares estimation. The climatological library TIGR was employed to generate IASI interferograms from LARA spectra. TIGR includes 2311 atmospheric scenarios, each characterized by temperature, water vapor, and ozone concentration profiles across a pressure grid from the surface to the top of the atmosphere. Our study focuses on CO, a critical trace gas for understanding air quality and climate forcing, which displays a characteristic absorption pattern in the 2050–2350 cm1 wavenumber range. Additionally, the study explores the potential of correlating interferogram characteristics with surface temperature and H2O content, aiming to enhance the accuracy of CO column retrievals. Starting with intuitive retrieval algorithms, we progressively increased complexity, culminating in a neural network-based algorithm. The results of the NN study demonstrate the feasibility of fast interferogram-domain retrievals, paving the way for operational applications. Full article
(This article belongs to the Section Atmospheric Remote Sensing)
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34 pages, 2064 KiB  
Article
Stereoselective Synthesis of Axially Chiral 5,5′-Linked bis-1-Arylisochromans with Antibacterial Activity
by Zoltán Czenke, Attila Mándi, Gergely Miklós Fedics, Roland Albert Barta, Attila Kiss-Szikszai, Anna Kurucz-Szabados, István Timári, Attila Bényei, Sándor Balázs Király, Eszter Ostorházi, Changsheng Zhang, Máté Kicsák and Tibor Kurtán
Int. J. Mol. Sci. 2025, 26(16), 7777; https://doi.org/10.3390/ijms26167777 - 12 Aug 2025
Viewed by 229
Abstract
Inspired by naturally occurring bis-isochromans such as penicisteckins, we envisaged the first synthesis of biaryl-type bis-1-arylisochromans containing a stereogenic ortho-trisubstituted biaryl axis. We achieved the stereoselective synthesis of 5,5′-linked heterodimeric bis-isochromans containing both central and axial chirality elements by [...] Read more.
Inspired by naturally occurring bis-isochromans such as penicisteckins, we envisaged the first synthesis of biaryl-type bis-1-arylisochromans containing a stereogenic ortho-trisubstituted biaryl axis. We achieved the stereoselective synthesis of 5,5′-linked heterodimeric bis-isochromans containing both central and axial chirality elements by performing diastereoselective Suzuki–Miyaura biaryl coupling reactions on two optically active 1-arylpropan-2-ol derivatives, followed by two oxa-Pictet–Spengler cyclizations with aryl aldehydes or methoxymethyl chloride. We studied the diastereoselectivity of the cyclization step, separated the stereoisomeric products with chiral preparative HPLC and determined the absolute configuration through a combination of vibrational circular dichroism (VCD), NMR and single-crystal X-ray diffraction analysis. We demonstrated that different aryl groups could be introduced into the two isochroman subunits, since the dimethoxyaryl subunit reacted faster, enabling the two oxa-Pictet–Spengler cyclizations to be performed separately with different aryl aldehydes. We also explored the acid-catalyzed isomerization and oxidation to axially chiral ortho-quinones in order to produce stereoisomeric and oxidized analogs, respectively. We identified the antibacterial activity of our target bis-isochromans against Bacillus subtilis and Enterococcus faecalis with minimum inhibitory concentrations down to 4.0 and 0.5 μg/mL, respectively, which depend on the stereochemistry and substitution pattern of the bis-isochroman skeleton. Full article
(This article belongs to the Special Issue Heterocyclic Compounds: Synthesis, Design, and Biological Activity)
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22 pages, 9002 KiB  
Article
Systematic Study of Preparing Porous CaCO3 Vaterite Particles for Controlled Drug Release
by Nan Zhang, Binhang Zhao, Pan Yang and Haifei Zhang
Nanomaterials 2025, 15(16), 1227; https://doi.org/10.3390/nano15161227 - 12 Aug 2025
Viewed by 266
Abstract
Porous CaCO3 vaterite particles have been widely used as drug carriers for biomedical applications due to their high biocompatibility and low production costs. However, controlling the particle size and porosity of CaCO3 nanoparticles with the desired crystalline phase is still challenging. [...] Read more.
Porous CaCO3 vaterite particles have been widely used as drug carriers for biomedical applications due to their high biocompatibility and low production costs. However, controlling the particle size and porosity of CaCO3 nanoparticles with the desired crystalline phase is still challenging. In this study, we have systematically investigated the preparation of CaCO3 nanoparticles under various conditions including precursor types/ratios/concentrations, additive concentrations (ethylene glycol), and temperatures. The materials were fully characterized by optical microscopy, scanning and transmission electron microscopy, infrared spectroscopy, powder X-ray diffraction, dynamic laser scattering, thermogravimetric analysis, and gas sorption. The impacts of the reaction parameters were rationalized and the mechanism for the formation of porous vaterite particles was suggested. It was possible to produce porous vaterite nanoparticles (200 nm) under the optimized conditions, which were further used as drug carrier to upload a model drug curcumin. The potential of using these vaterite particles for controlled drug release was demonstrated. Full article
(This article belongs to the Section Inorganic Materials and Metal-Organic Frameworks)
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