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Cesium lead halide nanostructures have highly tunable optical and optoelectronic properties. Establishing precise control in forming perovskite single-crystal nanostructures is key to unlocking the full potential of these materials. However, studying the growth kinetics of colloidal cesium lead halides is challenging due to their sensitivity to light, electron beam, and environmental factors like humidity. In this study, in situ observations of CsPbBr3-particle dynamics were made possible through extremely low dose liquid cell transmission electron microscopy, showing that oriented attachment is the dominant pathway for the growth of single-crystal CsPbBr3 architectures from primary nanocubes. In addition, oriented assembly and fusion of ligand-stabilized cubic CsPbBr3 nanocrystals are promoted by electron beam irradiation or introduction of polar additives that both induce partial desorption of the original ligands and polarize the nanocube surfaces. These findings advance our understanding of cesium lead halide growth mechanisms, aiding the controlled synthesis of other perovskite nanostructures.
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Cesium lead halide (CsPbX3, X = Br, Cl, and I) nanocrystals (NCs) are widely concerned and applied in many fields due to the excellent photoelectric performance. However, the toxicity of Pb and the loss of luminescence in water limit its application in vivo. A stable perovskite nanomaterial with good bioimaging properties is developed by incorporating europium (Eu) in CsPbX3 NCs followed with the surface coating of silica (SiO2) shell (CsPbX3:Eu@SiO2). Through the surface coating of SiO2, the luminescence stability of CsPbBr3 in water is improved and the leakage of Pb2+ is significantly reduced. In particular, Eu doping inhibits the photoluminescence quantum yield reduction of CsPbBr3 caused by SiO2 coating, and further reduces the release of Pb2+. CsPbBr3:Eu@SiO2 nanoparticles (NPs) show efficient luminescence in water and good biocompatibility to achieve cell imaging. More importantly, CsPb(ClBr)3:Eu@SiO2 NPs are obtained by adjusting the halogen components, and green light and blue light are realized in zebrafish imaging, showing good imaging effect and biosafety. The work provides a strategy for advanced perovskite nanomaterials toward biological practical application.
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Césio , Európio , Chumbo , Luminescência , Nanopartículas , Dióxido de Silício , Água , Peixe-Zebra , Animais , Dióxido de Silício/química , Európio/química , Nanopartículas/química , Chumbo/química , Césio/química , Água/química , Titânio/química , Óxidos , Compostos de CálcioRESUMO
Perovskite nanocrystals (NCs) have emerged as a promising building block for the fabrication of optic-/optoelectronic-/electronic devices owing to their superior characteristics, such as high absorption coefficient, rapid ion mobilities, and tunable energy levels. However, their low structural stability and poor surface passivation have restricted their application to next-generation devices. Herein, a drug delivery system (DDS)-inspired post-treatment strategy is reported for improving their structural stability by doping of Ag into CsPbBr3 (CPB) perovskite NCs; delivery to damaged sites can promote their structural recovery slowly and uniformly, averting the permanent loss of their intrinsic characteristics. Ag NCs are designed through surface-chemistry tuning and structural engineering to enable their circulation in CPB NC dispersions, followed by their delivery to the CPB NC surface, defect-site recovery, and defect prevention. The perovskite-structure healing process through the DDS-type process (with Ag NCs as the drug) is analyzed by a combination of theoretical calculations (with density functional theory) and experimental analyses. The proposed DDS-inspired healing strategy significantly enhances the optical properties and stability of perovskite NCs, enabling the fabrication of white light-emitting diodes.
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MAIN CONCLUSION: This is the first report on the involvement of abscisic acid signaling in regulating post-germination growth under Cs stress, not related to potassium deficiency. Cesium (Cs) is known to exert toxicity in plants by competition and interference with the transport of potassium (K). However, the precise mechanism of how Cs mediates its damaging effect is still unclear. This fact is mainly attributed to the large effects of lower K uptake in the presence of Cs that shadow other crucial effects by Cs that were not related to K. RNA-seq was conducted on Arabidopsis roots grown to identify putative genes that are functionally involved to investigate the difference between Cs stress and low K stress. Our transcriptome data demonstrated Cs-regulated genes only partially overlap to low K-regulated genes. In addition, the divergent expression trend of High-affinity K+ Transporter (HAK5) from D4 to D7 growth stage suggested participation of other molecular events besides low K uptake under Cs stress. Potassium deficiency triggers expression level change of the extracellular matrix, transfer/carrier, cell adhesion, calcium-binding, and DNA metabolism genes. Under Cs stress, genes encoding translational proteins, chromatin regulatory proteins, membrane trafficking proteins and defense immunity proteins were found to be primarily regulated. Pathway enrichment and protein network analyses of transcriptome data exhibit that Cs availability are associated with alteration of abscisic acid (ABA) signaling, photosynthesis activities and nitrogen metabolism. The phenotype response of ABA signaling mutants supported the observation and revealed Cs inhibition of root growth involved in ABA signaling pathway. The rather contrary response of loss-of-function mutant of Late Embryogenesis Abundant 7 (LEA7) and Translocator Protein (TSPO) further suggested low K stress and Cs stress may activate different salt tolerance responses. Further investigation on the crosstalk between K transport, signaling, and salt stress-responsive signal transduction will provide a deeper understanding of the mechanisms and molecular regulation underlying Cs toxicity.
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Proteínas de Arabidopsis , Arabidopsis , Deficiência de Potássio , Arabidopsis/metabolismo , Ácido Abscísico/metabolismo , Césio/metabolismo , Césio/farmacologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de PlantasRESUMO
We report an idea for the synthesis of oligopeptides using a solvent-free ball milling approach. Our concept is inspired by block play, in which it is possible to construct different objects using segments (blocks) of different sizes and lengths. We prove that by having a library of short peptides and employing the ball mill mechanosynthesis (BMMS) method, peptides can be easily coupled to form different oligopeptides with the desired functional and biological properties. Optimizing the BMMS process we found that the best yields we obtained when TBTU and cesium carbonate were used as reagents. The role of Cs2CO3 in the coupling mechanism was followed on each stage of synthesis by 1H, 13C and 133Cs NMR employing Magic Angle Spinning (MAS) techniques. It was found that cesium carbonate acts not only as a base but is also responsible for the activation of substrates and intermediates. The unique information about the BMMS mechanism is based on the analysis of 2D NMR data. The power of BMMS is proved by the example of different peptide combinations, 2+2, 3+2, 4+2, 5+2 and 4+4. The tetra-, penta-, hexa-, hepta- and octapeptides obtained under this project were fully characterized by MS and NMR techniques.
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Carbonatos , Césio , Oligopeptídeos , Césio/química , Carbonatos/química , Oligopeptídeos/química , Espectroscopia de Ressonância Magnética , Solventes/químicaRESUMO
Understanding the transport of 137Cs emitted during the Fukushima accident is challenging because the critical emissions that produced the high-deposition area are not adequately resolved in existing source terms. This paper presents an objective inverse reconstruction of these emissions by fusing atmospheric concentrations with a-priori emissions extracted from total depositions. This extraction, previously considered impossible for complex real-world accidents, is achieved by identifying the critical temporal formation process of depositions in the high-deposition area and estimating the corresponding emissions by using an atmospheric transport model. The reconstructed source term reveals two emission peaks from 10:00-11:00 and 14:00-15:00 on March 15, which agree with the in situ pressure measurements and accident analysis, suggesting that they came from pressure drops in the primary containment vessels of Units 3 and 2, respectively. This finding explains the environmental observations of spherical 137Cs particles. The source term also objectively and independently confirms the widely used reverse estimate. The corresponding 137Cs transport simulations better match the various observations than those produced by other source terms, proving that the two-peak emission creates a high-deposition area. The proposed method outperforms the direct fusion of deposition and atmospheric concentration observations, providing a robust tool for multiobservation fusion.
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Poluentes Radioativos do Ar , Atmosfera , Radioisótopos de Césio , Acidente Nuclear de Fukushima , Monitoramento de Radiação , Radioisótopos de Césio/análise , Poluentes Radioativos do Ar/análise , Atmosfera/química , Japão , Modelos TeóricosRESUMO
Recently, the utilization of metal halide perovskites in sensing and their application in environmental studies have reached a new height. Among the different metal halide perovskites, cesium lead halide perovskites (CsPbX3; X = Cl, Br, and I) and composites have attracted great interest in sensing applications owing to their exceptional optoelectronic properties. Most CsPbX3 nanostructures and composites possess great structural stability, luminescence, and electrical properties for developing distinct optical and photonic devices. When exposed to light, heat, and water, CsPbX3 and composites can display stable sensing utilities. Many CsPbX3 and composites have been reported as probes in the detection of diverse analytes, such as metal ions, anions, important chemical species, humidity, temperature, radiation photodetection, and so forth. So far, the sensing studies of metal halide perovskites covering all metallic and organic-inorganic perovskites have already been reviewed in many studies. Nevertheless, a detailed review of the sensing utilities of CsPbX3 and composites could be helpful for researchers who are looking for innovative designs using these nanomaterials. Herein, we deliver a thorough review of the sensing utilities of CsPbX3 and composites, in the quantitation of metal ions, anions, chemicals, explosives, bioanalytes, pesticides, fungicides, cellular imaging, volatile organic compounds (VOCs), toxic gases, humidity, temperature, radiation, and photodetection. Furthermore, this review also covers the synthetic pathways, design requirements, advantages, limitations, and future directions for this material.
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Cesium lead halide perovskite nanocrystals (PNCs) have emerged as a potential next-generation single quantum emitter (QE) material for quantum optics and quantum information science. Optical dephasing processes at cryogenic temperatures are critical to the quality of a QE, making a mechanistic understanding of coherence losses of fundamental interest. We use photon-correlation Fourier spectroscopy (PCFS) to obtain a lower bound to the optical coherence times of single PNCs as a function of temperature. We find that 20 nm CsPbBr3 PNCs emit nearly exclusively into a narrow zero-phonon line from 4 to 13 K. Remarkably, no spectral diffusion is observed at time scales of 10 µs to 5 ms. Our results suggest that exciton dephasing in this temperature range is dominated by elastic scattering from phonon modes with characteristic frequencies of 1-3 meV, while inelastic scattering is minimal due to weak exciton-phonon coupling.
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To understand the relationship between the radioactive cesium (Cs) concentration in muscle of Japanese flounder Paralichthys olivaceus and the species' biological characteristics (size, sex, and age) under conditions of ecological equilibrium (i.e., distributed among ecosystem components over sufficient time, and with nearly constant ratios of Cs concentration in organisms to the concentration in water) as existed before the accident at the Fukushima Dai-ichi Nuclear Power Station (FDNPS), Japan, in 2011, we examined stable Cs, as it is thought to exist in equilibrium in the environment and behave similarly to radioactive Cs in aquatic animals. The concentration of stable Cs in 241 P. olivaceus (range 216-782 mm total length [TL]) collected in Sendai Bay, approximately 90 km north of the FDNPS, in June-July 2015 was expressed as an exponential function with size as an independent variable; the results show the concentration of stable Cs doubled with an increase in TL of 442 mm. Next, to evaluate the cause of the size-dependent change in stable Cs concentration, we examined 909 individuals (200-770 mm TL) collected in September 2013-July 2015 to determine their feeding habit based on size. Analysis of the frequency of occurrence of prey organisms in stomach contents showed that sand lance Ammodytes japonicus (55-180 mm standard length [SL]) was the most consistently consumed across size classes. Analysis on a wet-mass basis showed that A. japonicus and anchovy Engraulis japonicus (65-130 mm SL) were the main food of P. olivaceus sized 200-599 mm TL, whereas chub mackerel Scomber japonicus (120-230 mm SL) and two species of flatfishes (180-205 mm SL) were abundant in the diet of P. olivaceus sized ≥600 mm TL. All these prey items were presumed to have similar concentrations of stable Cs. Based on the above, the effect of diet on the relationship between stable Cs in muscle and fish size was considered negligible. That the diet of P. olivaceus largely did not change with size was also confirmed by C and N stable isotope ratios in P. olivaceus and their prey species. Therefore, the Cs-size relationship is probably determined by changes in the balance between the rate of Cs intake from food and seawater and the excretion rate during growth, both of which change as functions of body mass. Values of stable Cs concentrations among environmental components and animals appear to be a valid indicator for understanding the radioactive Cs distribution in the marine environment and aquatic animals under the equilibrium state, as existed before the 2011 nuclear accident.
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Linguados , Linguado , Acidente Nuclear de Fukushima , Animais , Tamanho Corporal , Césio/análise , Radioisótopos de Césio/análise , Dieta/veterinária , Ecossistema , Japão , Masculino , FemininoRESUMO
Conventional liquid treatments for large-scale, low-level radioactive wastewater, such as ion exchange and waste solidification, face challenges due to the large amounts of secondary waste and high disposal costs. A new large-scale decontamination method is proposed that uses kapok fiber composites for rapid radionuclide adsorption and high volume reduction to minimize secondary waste. The composite consists of natural zeolite and kapok holocellulose, which has high water-soaking ability and low-temperature pyrolysis. The kapok composites, fabricated using a commercial wet-laid nonwoven manufacturing process, absorbs 99% of low-level radioactive cesium in 20 min, reducing the volume by 98% and the weight by 47% at 300 °C. The low-temperature pyrolysis process below 300 °C prevents cesium desorption and gasification by avoiding zeolite destruction. The mass-producible kapok composites can be used for adsorbing various radionuclides in large-scale wastewater by attaching specific adsorbents for target isotopes to the composites.
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Resíduos Radioativos , Zeolitas , Águas Residuárias , Césio , Radioisótopos , Adsorção , Resíduos Radioativos/prevenção & controleRESUMO
Radioactive wastes often contain amorphous and crystalline phases, and vapor hydration can affect their durability. In this study, Cs-clinoptilolite was heated (at 1100 °C and for 2-36 h) to prepare the samples that were composed mainly of an amorphous phase (AmP) and CsAlSi5O12 (≥94%) with minor CsAlSi2O6. Six samples with an AmP/CsAlSi5O12 ratio from 26.5 to 0.1 were kept at 21 °C and 55% relative humidity, and their hydration was measured via thermogravimetry (TG) over a period of almost six years. The hydration that resulted was directly related to the AmP quantity. The increase in water content followed a logarithmic trend over time. It reached 1.95% in the AmP-richest material, while it attained only 0.07% in the most crystalline sample. The hydrolysis of the AmP led to an increase over time in the tightly bound water. Samples with an AmP of ≤19% demonstrated slightly higher durability due to the lower Cs content in the AmP.
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Radioactive nuclides cesium (Cs) and strontium (Sr) possess long half-lives, with 135Cs at approximately 2.3 million years and 87Sr at about 49 billion years. Their persistent accumulation can result in long-lasting radioactive contamination of soil ecosystems. This study employed geo-accumulation index (Igeo), pollution load index (PLI), potential ecological risk index (PEPI), health risk assessment model (HRA), and Monte Carlo simulation to evaluate the pollution and health risks of Cs and Sr in the surface soil of different functional areas in a typical mining city in China. Positive matrix factorization (PMF) model was used to elucidate the potential sources of Cs and Sr and the respective contribution rates of natural and anthropogenic sources. The findings indicate that soils in the mining area exhibited significantly higher levels of Cs and Sr pollution compared to smelting factory area, agricultural area, and urban residential area. Strontium did not pose a potential ecological risk in any studied functional area. The non-carcinogenic health risk of Sr to the human body in the study area was relatively low. Because of the lack of parameters for Cs, the potential ecological and human health risks of Cs was not calculated. The primary source of Cs in the soil was identified as the parent material from which the soil developed, while Sr mainly originated from associated contamination caused by mining activities. This research provides data for the control of Cs and Sr pollution in the surface soil of mining city.
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Radioisótopos de Césio , Mineração , Poluentes Radioativos do Solo , Medição de Risco , China , Poluentes Radioativos do Solo/análise , Radioisótopos de Césio/análise , Humanos , Radioisótopos de Estrôncio/análise , Césio/análise , Cidades , Solo/química , Método de Monte Carlo , Monitoramento de RadiaçãoRESUMO
In our previous study, the decontamination efficiency of cesium-137 (137Cs) by Napier grass (Pennisetum purpureum Schum.) in the field was shown to be variable and often influenced by natural environmental factors. To elucidate the factors influencing this variable 137Cs-decontamination efficiency, we investigated the influences of soil type and drought stress on Cs accumulation using cesium-133 (133Cs) in Napier grass grown in plastic containers. The experiment was performed using two soil types (Soil A and B) and three different soil moisture conditions: well-watered control (CL), slight drought stress (SD), and moderate drought stress (MD). Overall, our results indicate that soil type and drought have a significant impact on plant growth and 133Cs accumulation in Napier grass. Plant height (PH), tiller number (TN), leaf width (Wleaf), and dry matter weight of aboveground parts (DWabove) and root parts (DWroot) in Soil B were greater than those in Soil A. Drought stress negatively affected chlorophyll fluorescence parameters (maximal quantum efficiency of photosystem (PS) II photochemistry and potential activity of PS II), PH, TN, Wleaf, DWabove, DWroot, and total 133Cs content (TCs), but it had a positive effect on 133Cs concentration. The 133Cs concentration in the aboveground parts (Csabove) was increased by MD approximately 1.62-fold in Soil A and 1.11-fold in Soil B compared to each CL counterpart. The TCs in the aboveground parts (TCsabove) decreased due to drought by approximately 19.9%-39.0% in Soil A and 49.9%-62.7% in Soil B; however, there was no significant effect on TCsabove due to soil type. The results of this study indicate that soil moisture is a key factor in maintaining Napier grass 137Cs-decontamination efficiency.
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Radioisótopos de Césio , Secas , Pennisetum , Poluentes Radioativos do Solo , Radioisótopos de Césio/metabolismo , Poluentes Radioativos do Solo/metabolismo , Pennisetum/metabolismo , Solo/químicaRESUMO
Radioisotope leaking from nuclear waste has become an intractable problem due to its gamma radiation and strong water solubility. In this work, a novel porous ZnFC-PA/PSF composite sphere was fabricated by immobilization of ferrocyanides modified zinc phytate into polysulfone (PSF) substrate for the treatment of Cs-contaminated water. The maximum adsorption capacity of ZnFC-PA/PSF was 305.38 mg/g, and the removal efficiency of Cs+ was reached 94.27% within 2 hr. The ZnFC-PA/PSF presented favorable stability with negligible dissolution loss of Zn2+ and Fe2+ (< 2%). The ZnFC-PA/PSF achieved high-selectivity towards Cs+ (Kd = 2.24×104 mL/g) even in actual geothermal water. The adsorption mechanism was inferred to be the ion-exchange between Cs+ and K+. What's more, ZnFC-PA/PSF worked well in the fixed-bed adsorption (E = 91.92%), indicating the application potential for the hazardous Cs+ removal from wastewater.
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Poluentes Químicos da Água , Adsorção , Poluentes Químicos da Água/química , Purificação da Água/métodos , Sulfonas/química , Polímeros/química , Porosidade , Césio/química , Eliminação de Resíduos Líquidos/métodos , Zinco/química , Águas Residuárias/químicaRESUMO
The high-rate ethanol electrosynthesis from CO2 is challenging due to the low selectivity and poor activity, which requires the competition with other reduction products and H2 . Here, the electrochemical reconstruction of Cs3 Cu2 Cl5 perovskite to form surface Cl-bonded, low-coordinated Cs modified Cu(200) nanocubes (CuClCs), is demonstrated. Density functional theory calculations reveal that the CuClCs structure possesses low Bader charges and a large coordination capacity; and thus, can promote the CO2 -to-ethanol pathway via stabilizing C-O bond in oxygenate intermediates. The CuClCs catalyst exhibits outstanding partial current densities for producing ethanol (up to 2124 ± 54 mA cm-2 ) as one of the highest reported values in the electrochemical CO2 or CO reduction. This work suggests an attractive strategy with surface alkali-metal cations for ampere-level CO2 -to-ethanol electrosynthesis.
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Lead halide-based perovskites solar cells (PSCs) are intriguing candidates for photovoltaic technology due to their high efficiency, low cost, and simple fabrication processes. Currently, PSCs with efficiencies of >25% are mainly based on methylammonium (MA)-free and bromide (Br) free, formamide lead iodide (FAPbI3 )-based perovskites, because MA is thermally unstable due to its volatile nature and Br incorporation will induce blue shift in the absorption spectrum. Therefore, MA-free, Br-free formamidine-based perovskites are drawing huge research attention in recent years. The hole transporting layer (HTL) is crucial in fabricating highly efficient and stable inverted p-i-n structured PSCs by enhancing charge extraction, lowering interfacial recombination, and altering band alignment, etc. Here, this work employs a NiOx /PTAA bi-layer HTL combined with GuHCl (guanidinium hydrochloride) additive engineering and PEAI (phenylethylammonium iodide) passivation strategy to optimize the charge carrier dynamics and tune defects chemistry in the MA-free, Br-free RbCsFAPbI3 -based perovskite absorber, which boosts the device efficiency up to 22.78%. Additionally, the device retains 95% of its initial performance under continuous 1 sun equivalent LED light illumination at 45 °C for up to 500 h.
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A mild photocatalyzed approach to achieve the α-alkylation of esters via formation of an α -radical is disclosed here. Cesium enolates of esters were generated in situ using Cs2CO3 as a base. A subsequent photocatalyzed oxidation at the α-carbon of these enolates produced an α-radical that was added into activated alkenes. This is the first example accessing the α-carbon radical of esters in photoredox catalyed transformations.
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BACKGROUND: The introduction of Cesium-131 (Cs-131) as a radiation source has led to a resurgence of brachytherapy for central nervous system (CNS) tumors. The aim of this study was to evaluate the safety and efficacy of the largest cohort of Cs-131 patients to-date. METHODS: A retrospective review of all CNS tumors treated with resection and adjuvant Cs-131 brachytherapy at New York-Presbyterian/Weill Cornell from 2010 to 2021 was performed. Overall survival (OS) and local control (LC) were assessed with Kaplan-Meier methodology. Univariable analysis was conducted to identify patient factors associated with local recurrence or radiation necrosis. RESULTS: Adjuvant Cs-131 brachytherapy following resection was performed in 119 patients with a median follow-up time of 11.8 (IQR 4.7-23.6) months and a mean of 22.3 +/-30.3 months. 1-year survival rates were 53.3% (95%CI 41.9-64.6%) for brain metastases (BrM), 45.9% (95%CI 24.8-67.0%) for gliomas, and 73.3% (95%CI 50.9-95.7%) for meningiomas. 1-year local control rates were 84.7% for BrM, 34.1% for gliomas, and 83.3% for meningiomas (p < 0.001). For BrM, local control was superior in NSCLC relative to other BrM pathologies (90.8% versus 76.5%, p = 0.039). Radiographic radiation necrosis (RN) was identified in 10 (8.4%) cases and demonstrated an association with smaller median tumor size (2.4 [IQR 1.8-2.7 cm] versus 3.1 [IQR 2.4-3.8 cm], p = 0.034). Wound complications occurred in 14 (11.8%) patients. CONCLUSIONS: Cs-131 brachytherapy demonstrated a favorable safety and efficacy profile characterized by high rates of local control for all treated pathologies. The concept of brachytherapy has seen a resurgence given the excellent results when Cs-131 is used as a source.
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Braquiterapia , Neoplasias Encefálicas , Glioma , Neoplasias Pulmonares , Neoplasias Meníngeas , Meningioma , Humanos , Radioisótopos de Césio , Resultado do Tratamento , Meningioma/cirurgia , Braquiterapia/efeitos adversos , Braquiterapia/métodos , Neoplasias Encefálicas/cirurgia , Estudos Retrospectivos , Neoplasias Meníngeas/cirurgia , Necrose/etiologia , Recidiva Local de Neoplasia/cirurgiaRESUMO
Radionuclides released from nuclear accidents or explosions pose long-term threats to ecosystem health. A prominent example is wild boar contamination in central Europe, which is notorious for its persistently high 137Cs levels. However, without reliable source identification, the origin of this decades old problem has been uncertain. Here, we target radiocesium contamination in wild boars from Bavaria. Our samples (2019-2021) range from 370 to 15,000 Bq·kg-1 137Cs, thus exceeding the regulatory limits (600 Bq·kg-1) by a factor of up to 25. Using an emerging nuclear forensic fingerprint, 135Cs/137Cs, we distinguished various radiocesium source legacies in their source composition. All samples exhibit signatures of mixing of Chornobyl and nuclear weapons fallout, with 135Cs/137Cs ratios ranging from 0.67 to 1.97. Although Chornobyl has been widely believed to be the prime source of 137Cs in wild boars, we find that "old" 137Cs from weapons fallout significantly contributes to the total level (10-68%) in those specimens that exceeded the regulatory limit. In some cases, weapons-137Cs alone can lead to exceedances of the regulatory limit, especially in samples with a relatively low total 137Cs level. Our findings demonstrate that the superposition of older and newer legacies of 137Cs can vastly surpass the impact of any singular yet dominant source and thus highlight the critical role of historical releases of 137Cs in current environmental pollution challenges.
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Radioisótopos de Césio , Ecossistema , Suínos , Animais , Sus scrofaRESUMO
Current methods for evaluating catalytic degradation reactions of environmental pollutants primarily rely on chromatography that often suffers from intermittent analysis, a long turnaround period, and complex sample pretreatment. Herein, we propose a quantitative time-resolved visualization method to evaluate the progress of catalytic degradation reactions by integrating sample pretreatment [single-drop microextraction, (SDME)], fluorescence sensing, and a smartphone detection platform. The dechlorination reaction of chlorobenzene derivatives was first investigated to validate the feasibility of this approach, in which SDME plays a critical role in direct sample pretreatment, and inorganic CsPbBr3 perovskite encapsulated in a metal-organic framework (MOF-5) was utilized as the fluorescent chromogenic agent (FLCA) in SDME to realize fast in situ colorimetric detection via the color switching from green (CsPbBr3) to blue (chlorine lead bromide, inorganic CsPbCl3 perovskite). The smartphone, which can calculate the B/G value of FLCA, serves as a data output window for quantitative time-resolved visualization. Further, a [Eu(PMA)]n (PMA= pyromellitic acid) fluorescent probe was constructed to use as an FLCA for the in situ evaluation of cinnamaldehyde and p-nitrophenol catalytic reduction. This approach not only minimizes the utilization of organic solvents and achieves quantitively efficient time-resolved visualization but also provides a feasible method for in situ monitoring of the progress of catalytic degradation reactions.