Search Results (542)

In optical one-dimensional grating-on-layer planar structures, an optical resonance occurs when the incident light wave becomes phase-matched to a leaky waveguide mode excited in the layer underneath the grating by an appropriate tuning of the grating periodicity. Changing the refractive indices of the grating’s constituents, and/or thickness, changes the resonance frequency. In the case of a two-dimensional grating atop such a smooth layer, a similar and also cavity-mode resonance can occur. This idea has straightforward usage in diverse optical sensor applications. In this study, a novel guided-mode resonance sensor design for detecting glucose and hemoglobin in minute concentrations at a wide range of incidence angles is presented. In this design, materials of the grating, such as a polymer and cesium-lead halide with a perovskite crystal structure, are examined, which will allow flexible, low-cost fabrication by soft-lithography/imprint-lithography methods. The sensitivity, figure of merit, and quality factor are reported for one- and two-dimensional grating structures. The simulations performed are based on rigorous coupled-wave analysis. Optical resonance quality factor of ∼$5·{10}^5$ is achieved at oblique incidence for a structure comprising a one-dimensional grating etched in a poly-vinylidene chloride layer atop a silicon nitride waveguide layer on a substrate. Record values of the above-noted characteristics are achieved with a synergetic interplay of the materials, structural dimensions, incidence angle, polarization, and grating geometry. Full article

With nuclear power playing an increasing role in efforts to reduce carbon emissions, the development of effective and sensitive monitoring tools for (radio)toxic elements in the environment has become essential. This review highlights recent advances in fluorescent probes developed for the detection of key elements associated with the nuclear industry, including uranium, cesium, strontium, technetium, zirconium, and beryllium. Various sensor platforms, ranging from organic ligands and DNAzymes to metal–organic frameworks and quantum dots, offer promising features, such as high sensitivity, selectivity, and suitability for environmental matrices. Several recent designs now achieve detection limits in the nanomolar to picomolar range, revealing new perspectives for environmental and biological applications. Full article

The behavior of S and Cs during the alternate adsorption of each adsorbate on the Ni(100) surface is studied at room and elevated temperatures by means of low-energy electron diffraction (LEED), Auger electron spectroscopy (AES), thermal desorption spectroscopy (TDS) and work function (WF) measurements. For Cs deposition on the S-covered Ni(100) surface, the presence of sulfur increases the binding energy and the maximum amount of adsorbed cesium, as happens with other alkalis too. The first Cs overlayer is disordered, while the second strongly interacts with S with a tendency toward a Cs_xS_y surface compound formation. This interaction causes the gradual demetallization of the Cs overlayer with the increasing S coverage in the underlayer. When the Cs_xS_y stoicheometry is complete, however, subsequent Cs deposition forms an independent rather metallic overlayer. When the sulfated covers the surface, S(0.5ML)/Ni(100) is preheated to 1100 K, the S-Ni bond strengthens and S-Cs interaction correspondingly weakens to a degree that the S underlayer retains a periodic structure on the Ni substrate. This behavior indicates that the preheated S/Ni(100) surface is passivated to a degree against Cs with reduced mobility of sulfur adatoms. Differently, when S is adsorbed on the Cs-covered Ni(100) surface at room temperature, sulfur adatoms diffuse underneath the Cs overlayer to interact with the nickel substrate and form the same structural phases as on a clean surface. During that process, the sticking coefficient of sulfur remains constant regardless of the amount of pre-deposited cesium. The presence of Cs, however, increases the amount of S that can be deposited on the Ni substrate, probably in favor of the Cs_xS_y compound formation, which demetallizes the surface independent of the sequence of adsorption. Full article

¹³⁷Cs activity concentration in soil was analyzed yearly for 13 years (2010–2022) in an undisturbed area in Mexico. The temporal variation at 17 sampling points is consistent with the natural radioactive decrease of ¹³⁷Cs, excluding increased activity concentration detected after the Fukushima accident at 4 sampling points. Geospatial analysis was permitted to obtain ¹³⁷Cs activity concentration distributions for each year. The highest ¹³⁷Cs activity concentration was found at higher topography levels and close to intermittent water streams: 87.1 ± 5.5 Bq kg⁻¹ for the year 2011, which increased to 135.5 ± 14.5 Bq kg⁻¹ for the year 2013, and then ¹³⁷Cs decreased down to 46.4 ± 4.0 Bq kg⁻¹ by the year 2022. The lowest ¹³⁷Cs activity concentration was in the range of 0.6 ± 0.1 Bq kg⁻¹ to 13.5 ± 1.0 Bq kg⁻¹ at the points far from the undisturbed area, probably due to anthropogenic activities. Full article

This study presents a high-fidelity digital twin (DT) framework designed to evaluate and improve vertiport operations for Advanced Air Mobility (AAM). By integrating Unreal Engine, AirSim, and Cesium, the framework enables real-time simulation of Unmanned Aerial Vehicles (UAVs), including unmanned electric vertical take-off and landing (eVTOL) operations under nominal and disrupted conditions, such as adverse weather and engine failures. The DT supports interactive visualisation and risk-free analysis of decision-making protocols, vertiport layouts, and UAV handling strategies across multi-scenarios. To validate system realism, mixed-reality experiments involving physical UAVs, acting as surrogates for eVTOL platforms, demonstrate consistency between simulations and real-world flight behaviours. These UAV-based tests confirm the applicability of the DT environment to AAM. Intelligent algorithms detect Final Approach and Take-Off (FATO) areas and adjust flight paths for seamless take-off and landing. Live environmental data are incorporated for dynamic risk assessment and operational adjustment. A structured capacity evaluation method is proposed, modelling constraints including turnaround time, infrastructure limits, charging requirements, and emergency delays. Mitigation strategies, such as ultra-fast charging and reconfiguring the layout, are introduced to restore throughput. This DT provides a scalable, drone-integrated, and data-driven foundation for vertiport optimisation and regulatory planning, supporting safe and resilient integration into the AAM ecosystem. Full article

Metal halide perovskites have appeared as a promising semiconductor for high-efficiency and low-cost photovoltaic technologies. However, their performance and long-term stability are dramatically constrained by defects at the surface and grain boundaries of polycrystalline perovskite films formed during the processing. Herein, we propose a defect-targeted passivation strategy using 2-chlorocinnamic acid (2-Cl) to simultaneously enhance the efficiency and stability of perovskite solar cells (PSCs). The crystallization kinetics, film morphology, and optical and electronic properties of the used formamidinium–cesium lead halide (FA_0.85Cs_0.15Pb(I_0.95Br_0.05)₃, FACs) absorber were modulated and systematically investigated by various characterizations. Mechanistically, the carbonyl group in 2-Cl coordinates with undercoordinated Pb²⁺ ions, while the chlorine atom forms Pb–Cl bonds, effectively passivating the surface and interfacial defects. The optimized FACs perovskite film was incorporated into inverted (p-i-n) PSCs with a typical architecture of ITO/NiO_x/PTAA/Al₂O₃/FACs/PEAI/PCBM/BCP/Ag. The optimal device delivers a champion power conversion efficiency (PCE) of 22.58% with an open-circuit voltage of 1.14 V and a fill factor of 82.8%. Furthermore, the unencapsulated devices retain 90% of their initial efficiency after storage in ambient air for 30 days and 83% of their original PCE after stress under 1 sun illumination with maximum power point tracking at 50 °C in a N₂ environment, demonstrating the practical potential of dual-site molecular passivation for durable perovskite photovoltaics. Full article

Climate change represents one of the main challenges of this century. The hazards generated by this process are various and involve territorial assets all over the globe. Hydrogeological risk represents one of these aspects, and the violence of rain precipitations has led experts to focus their interest on the study of geotechnical assets in relation to these dangerous weather events. At the same time, geospatial representation in 3D WebGIS based on open-source solutions led specialists to employ this kind of technology to remotely analyze and monitor territorial events considering different sources of information. This study considers the construction of a 3D WebGIS framework for the real-time management of geospatial information developed with open-source technologies applied to the dynamic mapping of precipitation in the metropolitan area of Palermo (Italy) based on real-time weather station acquisitions. The structure considered is a WebGIS platform developed with Cesium.js JavaScript libraries, the Postgres database, Geoserver and Mapserver geospatial servers, and the Anaconda Python platform for activating real-time data connections using Python scripts. This framework represents a basic geospatial digital twin structure useful to municipalities, civil protection services, and firefighters for land management and for activating any preventive operations to ensure territorial safety. Furthermore, the open-source nature of the platform favors the free diffusion of this solution, avoiding expensive applications based on property software. The components of the framework are available and shared using GitHub. Full article

In recent years, with the development of science and technology and the transformation of economic structures, rubidium and cesium have gradually become indispensable rare metal resources as important materials for high-tech industries. However, the relationship between supply and demand of resources is unbalanced, industrial demand is much higher than production, and the rubidium and cesium resources in hard rock minerals such as traditional pegmatite minerals are no longer enough to support global scientific and technological upgrading. There is therefore an urgent need to expand sources of resource extraction and recovery to meet market demand. This paper summarizes the current feasible technologies for extracting rubidium and cesium from pegmatite minerals, silicate minerals, salt lake brines and other potential resources. Full article

Wild-growing edible mushrooms are known to bioaccumulate radionuclides from their environment, particularly the natural isotope potassium-40 (⁴⁰K) and anthropogenic cesium-137 (¹³⁷Cs). However, region-specific data for commercially relevant species in north-eastern Poland remain limited, despite the cultural and economic importance of mushroom foraging and export. This study aimed to assess the radiological safety of wild mushrooms intended for human consumption, with particular attention to regulatory compliance and potential exposure levels. In this study, 230 mushroom samples representing 19 wild edible species were analyzed using gamma spectrometry, alongside composite soil samples collected from corresponding foraging sites. The activity concentration of ¹³⁷Cs in mushrooms ranged from 0.94 to 159.0 Bq/kg fresh mass (f.m.), and that of ⁴⁰K from 64.4 to 150.2 Bq/kg f.m. None of the samples exceeded the regulatory limit of 1250 Bq/kg f.m. for ¹³⁷Cs. The highest estimated annual effective dose was 2.32 µSv from ¹³⁷Cs and 0.93 µSv from ⁴⁰K, with no exceedance of regulatory limits observed in any sample. A strong positive correlation was observed between ¹³⁷Cs activity in soil and mushroom dry mass (Spearman’s Rho = 0.81, p = 0.042), supporting predictable transfer patterns. Additionally, the implications of mushroom drying were assessed considering Council Regulation (Euratom) 2016/52, which mandates radionuclide levels in dried products be evaluated based on their reconstituted form. After such adjustment, even the most contaminated dried samples were found to comply with food safety limits. These findings confirm the radiological safety of wild mushrooms from north-eastern Poland and contribute novel data for a region with limited prior monitoring, in the context of current food safety regulations. Full article

Perovskite solar cells (PSCs) have already been reported as a promising alternative to traditional energy sources due to their excellent power conversion efficiency, affordability, and versatility, which is particularly relevant considering the growing worldwide demand for energy and increasing scarcity of natural resources. However, operational concerns under environmental stresses hinder its economic feasibility. Through the addition of cesium (Cs), this study investigates how to optimize perovskite solar cells (PSCs) based on methylammonium lead-iodide (MAPbI₃) by creating mixed-cation compositions of MA_1−xCs_xPbI₃ (x = 0, 0.25, 0.5, 0.75, 1) for devices A to E, respectively. The impact of cesium content on the following factors, such as open-circuit voltage (V_oc), short-circuit current density (J_sc), fill factor (FF), and power conversion efficiency (PCE), was investigated using simulation software, with ITO/TiO₂/MA_1−xCs_xPbI₃/Spiro-OMeTAD/Au as a device architecture. Due to diminished defect density, the device with x = 0.5 (MA_0.5Cs_0.5PbI₃) attains a maximum power conversion efficiency of 18.53%, with a V_oc of 0.9238 V, J_sc of 24.22 mA/cm², and a fill factor of 82.81%. The optimal doping density of TiO₂ is approximately 10²⁰ cm⁻³, while the optimal thicknesses of the electron transport layer (TiO₂, 10–30 nm), the hole-transport layer (Spiro-OMeTAD, about 10–20 nm), and the perovskite absorber (750 nm) were identified to maximize efficiency. The inclusion of a small amount of Cs may improve photovoltaic responses; however, at elevated concentrations (x > 0.5), power conversion efficiency (PCE) diminished due to the presence of trap states. The results show that mixed-cation perovskite solar cells can be a great commercially viable option because they strike a good balance between efficiency and performance. Full article

This study centers on the adsorption–flotation coupling extraction of rubidium (Rb⁺) and cesium (Cs⁺) within a titanium silicate (CTS)–cetyltrimethylammonium bromide (CTAB) system, systematically investigating the impacts of pH, aeration rate, CTAB concentration, and flotation time on the extraction efficiency of these elements. Single-factor experiments revealed that the optimal flotation efficiency was achieved when the pH ranged from 6 to 10, the aeration rate was set at 1000 r/min, the CTAB concentration was 0.2 mmol/L, and the flotation duration was 18 min. Under these conditions, the adsorption capacities for Rb⁺ and Cs⁺ were recorded as 128.32 mg/g and 185.47 mg/g, respectively. Employing the response surface optimization method to analyze the interactive effects of these four factors, we found that their order of significance was as follows: pH > aeration rate > CTAB concentration > flotation time. The optimized parameters were determined as pH 8.64, bubble formation rate 1121 r/min, CTAB concentration 0.26 mmol/L, and flotation time 18.47 min. Under these refined conditions, the flotation efficiency for both CTS–Rb and CTS–Cs surpassed any single-factor experiment scenario, with the flotation efficiencies for Rb⁺ and Cs⁺ reaching 95.05% and 94.82%, respectively. This methodology effectively extracts Rb⁺ and Cs⁺ from low-concentration liquid systems, while addressing the challenges of solid–liquid separation for powdered adsorption materials. It holds significant theoretical and practical reference value for enhancing the separation processes of low-grade valuable components and boosting overall separation performance. Full article

The present study systematically investigated the cesium (Cs) enrichment characteristics and physiological responses to Cs exposure in radish (Raphanus sativus L.) seedlings under hydroponic conditions through integrated physiological, biochemical, and transcriptome analyses. The results showed that the Cs content in radish roots, stems, and cotyledons increased progressively with rising Cs concentrations (0.25–2 mM), and Cs mainly accumulated in the cotyledon. The transfer factor (TF) increased by 63.29% (TF = 3.87) as the Cs concentration increased from 0.25 to 2 mM, while the biological concentration factor (BCF) decreased by 72.56% (BCF = 14.87). Severe growth inhibition was observed at 2 mM Cs stress, with biomass reduction reaching 29.73%. The carotenoid content decreased by 11.92%; however, the total chlorophyll content did not change significantly, and the photosynthesis of radish was not affected. In addition, Cs exposure disrupted mineral nutrient homeostasis, decreasing potassium (K), sodium (Na), magnesium (Mg), and iron (Fe) content. The superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities, reactive oxygen species (ROS), and malondialdehyde (MDA) content increased under the different Cs treatments, which indicated that Cs exposure induced oxidative stress response in radish seedlings. Transcriptome analysis detected a total of 4326 differentially expressed genes (DEGs), in which altered expression patterns in genes associated with mineral transport, antioxidant systems, and carotenoid biosynthesis pathways in radish under 2 mM Cs treatment were observed. In conclusion, this study comprehensively investigated the physiological and molecular responses of radish to Cs stress, revealing that Cs accumulation exhibited site-specific preference and concentration dependence and induced physiological disturbances, including growth inhibition and photosynthetic pigment metabolism alterations. At the transcription level, Cs activated the enzymatic antioxidant system, related genes, and stress-response pathways. Notably, this study is the first to demonstrate that Cs disrupts plant mineral nutrition homeostasis and inhibits carotenoid biosynthesis. These findings establish a crucial theoretical foundation for utilizing radish in Cs-contaminated phytoremediation strategies. Full article

Osteoporosis is a major public health concern, particularly among postmenopausal women. Environmental exposure to metals has been proposed as a potential contributor to osteoporosis, but human data remain limited and inconsistent. This study investigated changes in urinary concentrations of 20 metal(loid)s in patients with osteoporosis, as well as the association of these elements with bone mineral density (BMD), in a cohort of 380 postmenopausal women aged 50–70 years from Cascavel, Paraná, Brazil. Demographic, lifestyle, and clinical data were collected, and urinary concentrations of aluminum (Al), barium (Ba), cadmium (Cd), cobalt (Co), cesium (Cs), copper (Cu), mercury (Hg), lithium (Li), manganese (Mn), molybdenum (Mo), nickel (Ni), lead (Pb), rubidium (Rb), antimony (Sb), selenium (Se), tin (Sn), strontium (Sr), thallium (Tl), uranium (U), and zinc (Zn) were measured by inductively coupled plasma mass spectrometry. BMD was assessed at the lumbar spine, femoral neck, and total hip using dual-energy X-ray absorptiometry. Osteoporosis was diagnosed in 73 participants (19.2%). Osteoporotic women had significantly higher urinary concentrations of Cd, Mn, Pb, Sb, Sn, and Zn (p < 0.05). Statistically significant negative correlations were observed between BMD and urinary concentrations of Al, Cd, Hg, Mn, Sb, and U. After adjustment for confounders, elevated urinary concentrations of Cd, Mn, Pb, and Sb remained independently and significantly associated with higher odds of osteoporosis, with Cd (aOR = 1.495; p = 0.026) and Sb (aOR = 2.059; p = 0.030) showing the strongest associations. In addition, women with urinary concentrations above the 90th percentile for both Cd and Sb had a significantly higher prevalence of osteoporosis compared to those with lower levels (44.4% vs. 18.0%; p = 0.011). Longitudinal studies are needed to confirm causality and inform prevention strategies. Full article

The development of efficient scintillators emitting in the red and/or infrared spectral range represents an important scientific challenge, as such materials could find numerous practical applications. This work studies newly grown CsI:Yb,Sm and CsI:Eu,Sm single crystals demonstrating red and infrared luminescence. We measured luminescence spectra in the visible and near-IR range, excitation spectra across visible, UV, VUV, and X-ray ranges, Raman spectra, and thermoluminescence spectra. The results show that divalent europium and ytterbium ions can efficiently transfer excitation to samarium ions. The light output of the obtained crystals under X-ray excitation was roughly estimated from the X-ray luminescence spectra, with expected values of 37,000 photons/MeV for CsI:Yb,Sm and 40,000 photons/MeV for CsI:Eu,Sm. Full article

A complex salt roasting–water leaching process was developed and optimized for the efficient extraction of lithium (Li), rubidium (Rb), and cesium (Cs) from lepidolite. The effects of roasting parameters (temperature, time, and complex salt composition) and leaching parameters (temperature, time, and liquid–solid ratio) were systematically investigated. Optimal roasting conditions were found to be 900 °C for 60 min with a complex salt composition of Lepidolite:Na₂SO₄:CaCl₂:CaCO₃ = 1:0.5:0.3:0.05, while optimal leaching conditions were 60 °C, 60 min, and a liquid–solid ratio of 3:1, achieving the highest leaching efficiencies of 94.60%, 83.33%, and 82.95% for Li₂O, Rb₂O, and Cs₂O, respectively. XRD and SEM characterizations confirmed the decomposition of lepidolite, formation of water-soluble phases during roasting, and selective separation of Li, Rb, and Cs from insoluble phases during leaching. The porous structure of the roasted product facilitated the dissolution of target metals. This study provides valuable insights and guidance for the efficient extraction of Li, Rb, and Cs from lepidolite, contributing to the comprehensive utilization of this resource. Full article