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Background: While hilar cholangiocarcinoma (HCCA) patients commonly undergo radioactive stent (RS) insertion treatment, the relative benefits of unilateral versus bilateral RS insertion procedures remain to be established. Accordingly, this study was designed to evaluate the relative safety and efficacy of percutaneous bilateral and unilateral RS insertion for patients with HCCA. Methods: In total, 126 HCCA patients who underwent unilateral (n=64) or bilateral (n=62) RS insertion from January 2017 - December 2021 were included in this analysis. Treatment efficacy and long-term outcomes were compared between groups. The primary endpoint was stent patency, and the secondary endpoints included technical success rate, clinical success rate, local control rate, overall survival (OS), and complications. Results: The respective technical success rates in the unilateral and bilateral groups were 90.6% (58/64) and 93.5% (58/62) (P = 0.782). The clinical success rates were 82.8% and 86.2% in unilateral and bilateral groups, respectively (P = 0.608). Both groups exhibited comparable medial post-intervention bilirubin levels (100 vs. 99 mmol/L; P = 0.501), and restenosis occurred in 12 (20.7%) and 15 (25.9%) patients over the follow-up interval (P = 0.510). The stent reintervention rate was significantly higher in the unilateral group than bilateral group (66.7% vs. 0.0%, P < 0.001). The median stent patency in the unilateral and bilateral groups was 189 and 210 days, respectively (P = 0.796), while the median OS interval was 222 and 229 days, respectively (P = 0.969). Comparable cholangitis (17.2% vs. 22.4%, P = 0.485) and cholecystitis (3.4% vs. 3.4%, P = 1.000) rates were also detected in these two groups. Conclusions: In summary, HCCA patients exhibit comparable efficacy when undergoing unilateral and bilateral radioactive stenting, suggesting that unilateral RS can be routinely performed owing to the simpler nature of this procedure. [ABSTRACT FROM AUTHOR]

Radioactivity in coastal sediments in northern Vietnam was examined using data from five sediment cores to assess radioactivity concentrations and radiation risk indices. Radiation risk indices included radium equivalent activity (Raeq), the absorbed dose rate (ADR), the annual effective dose equivalent (AEDE), the activity utilization index (AUI), the external hazard index (Hex), the representative level gamma index (Iγr), and the annual gonadal effective dose rate (AGDE). The radioactivity concentrations of 40K, 232Th, 226Ra, 238U, and 137Cs were 567, 56.1, 35.1, 37.9, and 1.18 Bq/kg, respectively. The average concentrations of 40K, 232Th, 226Ra, and 238U were above the global average at five sites, except for 137Cs, which was low. The Raeq, Hex, and AUI indices were below the recommended values, while the AEDE, ADR, AGDE, and Iγr indices were above the recommended values. Moreover, 40K, 232Th, 226Ra, and 238U had significant impacts on the radiation hazard indices Raeq, ADR, AEDE, Iγr, AUI, Hex, and AGDE. There are three coastal sediment groups on the northern coast of Vietnam: Group 1 has a higher radioactivity and radiation risk index than Group 2 but a lower value than Group 3. Group 3 had the highest radioactivity and radiation risk index. The values of 40K, 232Th, 226Ra, and 238U and the ADR, AUI, Iγr, and AGDE indices in the sediment threaten the living environment. [ABSTRACT FROM AUTHOR]

Radioactive materials may contain primordial radionuclides, and radionuclides of anthropogenic, nuclear accident, and waste disposal which are present in marine environments. This review explores various approaches for the effective sampling and detection of marine radionuclides. The different types of samples that can be collected, including water, sediment, biota, and suspended particulate matter are discussed. Additionally, this paper discusses the various analytical techniques employed for radionuclide detection, such as gamma spectrometry and radiochemical separation. The review emphasizes the importance of choosing appropriate sampling and detection methods based on the specific radionuclides, environmental conditions, and the desired level of sensitivity. It also highlights the challenges associated with their sampling and detection in complex marine environments. These include low radionuclide concentrations, interference from natural matrices, and contamination risks. [ABSTRACT FROM AUTHOR]

This critical review explores the quantification, analysis, and detection of radionuclides in the environment using the diffusive gradients in thin films (DGT) technique. Radionuclides, unstable isotopes emitting ionising radiation, are present in the environment due to natural and anthropogenic sources for which concerns are raised about their impact on human health and ecosystems. DGT offers a unique passive sampling approach for understanding the behaviour of radionuclides and other trace elements. This review provides insights into method development, real case scenarios, advantages, limitations, and future perspectives of DGT in radionuclide analysis. In terms of method development, various isotopes have been analysed with varying significance based on origin, concentration, risks, and persistence. Notably, U, Th, Pu, Am, Cm, 99Tc, 226Ra, 137Cs, 134Cs, 232U, 237Np, and 152Eu have been measured, revealing their diverse roles in environmental radioactivity. Real case scenarios illustrate applications in uranium mining, water quality monitoring, and metal speciation studies, shedding light on mobility, bioavailability, and ecological impacts. DGT's advantages include in-situ monitoring, time-averaged mean concentrations, and comprehensive speciation insights. Challenges include potential influences from biofouling, temperature changes and specifically the possible degradation of the binding and diffuse layer due to ionising radiation in long term exposures. In addition, the distinction between fully labile free metal ions and partially labile metal-ligand complexes introduces a potential limitation in the DGT technique, hence being an opportunity for future studies. Looking forward, DGT is expected to contribute to radiation dose modelling, environmental risk assessment, and water quality monitoring, with ongoing developments enhancing its utility and accuracy. [ABSTRACT FROM AUTHOR]

Controlled drug delivery system (CDDS) allows active pharmaceutical agent (API) to be released over extended periods of time, ranging from days to months, by using drug-encapsulating devices. Such systems have a number of merits over conventional drug delivery techniques, including the ability to customize drug release rates, safeguard delicate medications, and improve patient comfort and compliance. Microspheres are suitable carriers for numerous controlled delivery applications owing to CDDS's high bioavailability, prolonged drug release features, biocompatibility and ability to encapsulate a wide range of medicines. This review paper discusses fabrication techniques for microparticles, preparation and characterization processes used to prepare these microspheres, various types of microspheres such as on the basis of drug release pattern (matrix, coated, reservoir) and on the basis of drug delivery system (mucoadhesive, floating, bio-adhesive, radioactive, polymeric, and magnetic, etc.), and the key variables affecting drug release rates from encapsulated particles. [ABSTRACT FROM AUTHOR]

Uranium (U) is a trace radioactive element distributed within the surface and ground waters through various sources, including natural and human-made activities. This study aimed to present a holistic review of uranium removal from groundwater. According to findings present study, in ground waters the highest concentration of uranium 27 to10,100 µg/L was found in USA, and the lowest concentration was3 to 8.6 µg/L found in India, while in surface waters the highest level of uranium 0.05 to 900 µg/L was found in Turkey, and the lowest concentration was 0.13 to 590 ng/L found in Japan, and the WHO and EPA guideline value of 30 µg/L. Various treatment techniques used for uranium removal, including adsorption, conventional coagulation, chemical precipitation, bioremediation, nanofiltration and reverse osmosis, and ion exchange, have been considered widely and established to propose acceptable findings. These methods can be used in future research to remove uranium (U (IV) and U(VI)) from polluted waters in both experimental and real-world. [ABSTRACT FROM AUTHOR]

The basic principle of microwave heating is introduced briefly, and the researches and applications of microwave heating in auxiliary leaching of uranium minerals, sintering of uranium dioxide ceramic pellets, nitrate pyrolysis denitrification, radioactive waste treatment and pre-treatment of radioactive element analysis are summarized・ The main problems and challenges of the application of microwave heating technology in nuclear industry were pointed out, and the future development direction and application prospect were prospected. [ABSTRACT FROM AUTHOR]

The minerals and metals industries are vital in the world's economy, yet their use of resources and waste generation pose considerable issues. The circular economy is a concept that establishes the foundation for economic operations that are carried out to run sustainably and to promote economic welfare, which in turn leads to an improvement in environmental quality. This paper offers a comprehensive literature analysis on the principles and efficacy of circular economy in mineral processing, specifically focusing on radioactive minerals. This research aims to develop a circular economy model that preserves resources, reduces waste production, and complies with regulatory rules on radioactive waste management. The study outlines a clear and structured circular economy model consisting of four modules: sample preparation, decomposition, partial extraction, and total precipitation. Each module integrates energy efficiency, heat recovery, renewable energy, water reuse, and chemical recycling. The validated model provides a roadmap for implementing circular economy principles in processing radioactive materials, contributing to achieving sustainable development goals. The government's agenda in pursuit of the Nationally Determined Contribution (NDC) can be aided by this model. This study suggests that reducing resource use and the volume of material, energy, and waste generated by technological processes can be achieved while still maintaining quality. That concept brings about a change in the mindset of designing a mineral processing installation. Based on the result of this study, further study may be focused on implementing strategies for each module of the studied object. [ABSTRACT FROM AUTHOR]

The detection and measurement of radionuclides are indispensable processes, crucially guided by particle and photon emission mechanisms. Regulatory agencies and policymakers demand precise measurements to ensure compliance with safety standards and environmental protection mandates. To convert detection rates into meaningful activity values, certain vital parameters must be derived, necessitating validation through reference measurements, technical innovations, and proficiency testing. Gross alpha activity assessment holds particular significance in both finished products and the waste generated within naturally occurring radioactive materials (NORM) industries. The thickness of the radiation source emerges as a pivotal factor influencing gross alpha activity determination, owing to the energy losses incurred through self-absorption processes. This study endeavors to comprehensively investigate the impact of self-absorption in relation to source thickness, alongside an exploration of the associated procedural considerations. The research encompasses theoretical examinations of the range and stopping power of alpha particles as they interact with the source material itself, complemented by empirical measurements involving sources of varying thicknesses. Specifically, this study examines the influence of source thickness on the measurement of alpha activity within radioactive waste materials, originating from front-end nuclear facilities. In the context of this study, liquid wastes arise during the ore processing into uranium concentrate (sodium diuranate), subsequently conveyed to tailing ponds in slurry form. Solid wastes, on the other hand, predominantly consist of waste rock fragments produced during mining operations. A notable observation underscores the significance of self-absorption correction factors: In their absence, the measured values of alpha-specific activity experience substantial underestimation. This investigation yields self-absorption correction factors that have been quantified for varying source thicknesses. For liquid wastes, a second-degree polynomial fit, and for solid waste, a linear fit have been applied to these correction factors, facilitating improved accuracy in alpha activity measurements within radioactive samples. This research not only enhances our understanding of the intricate interplay between source thickness and self-absorption but also provides valuable insights for refining measurement methodologies in radiological assessments, especially concerning gross alpha activities in radioactive waste materials. [ABSTRACT FROM AUTHOR]

In this paper, we have developed a methodology to estimate the spatiotemporal distribution of radiation air dose rates around the Fukushima Daiichi Nuclear Power Plant (FDNPP). In our exploratory data analysis, we found that (1) the temporal evolution of dose rates is composed of a log-linear decay trend and fluctuations of air dose rates that are spatially correlated among adjacent monitoring posts; and (2) the slope of the log-linear environmental decay trend can be represented as a function of the apparent initial dose rates, coordinate position, land-use type, and soil type. From these observations, we first estimated the log-linear decay trend at each location based on these predictors, using the random forest method. We then developed a modified Kalman filter coupled with a Gaussian process model to estimate the dose-rate time series at a given location and time. We applied this method to the Fukushima evacuation zone (as of March 2017), which included 17 monitoring post locations (with monitoring datasets collected between 2014 and 2018) and generated a time series of dose-rate maps. Our results show that this approach allows us to produce accurate spatial and temporal predictions of radiation dose-rate maps using limited spatiotemporal measurements.

Accurate determination of cross-sections for residual radionuclide products (spallation fragments) resulting from proton spallation reactions is imperative for the detection of primary and secondary particles etc. Experimental measurement of these cross-sections faces challenges due to the complexities associated with target preparation and detection of spallation fragments. Monte Carlo simulations have emerged as a potent tool for estimation of spallation fragments yield. This research, with introducing an innovative formulation method based on spallation yield, focuses on calculating the cross-section for the detection of primary and secondary particles in particle interaction with matter. Investigations indicate that the introduced method achieves remarkable agreement, ranging from 85.4% to 95.15%, with experimental outcomes at MeV energies. Consequently, this method can confidently be utilized for calculating the spallation cross-section fragments. In a case study, the spallation fragment cross-section was calculated for proton beam interaction with 222Rn in the range of 10 MeV to 60 MeV for the application of 222Rn detection. Among the 28 common spallation products of radon with the proton interaction in the energy range of 10 MeV to 60 MeV, elements 106Mo, 109Tc, 118Cd, 112Ru, 110Pd, and 114Rh exhibit dominant spallation cross-sections, emphasizing their exceptional significance.

Copyright of Uranium Mining & Metallurgy is the property of Uranium Mining & Metallurgy Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Accurate determination of cross-sections for residual radionuclide products (spallation fragments) resulting from proton spallation reactions is imperative for the detection of primary and secondary particles etc. Experimental measurement of these cross-sections faces challenges due to the complexities associated with target preparation and detection of spallation fragments. Monte Carlo simulations have emerged as a potent tool for estimation of spallation fragments yield. This research, with introducing an innovative formulation method based on spallation yield, focuses on calculating the cross-section for the detection of primary and secondary particles in particle interaction with matter. Investigations indicate that the introduced method achieves remarkable agreement, ranging from 85.4% to 95.15%, with experimental outcomes at MeV energies. Consequently, this method can confidently be utilized for calculating the spallation cross-section fragments. In a case study, the spallation fragment cross-section was calculated for proton beam interaction with 222Rn in the range of 10 MeV to 60 MeV for the application of 222Rn detection. Among the 28 common spallation products of radon with the proton interaction in the energy range of 10 MeV to 60 MeV, elements 106Mo, 109Tc, 118Cd, 112Ru, 110Pd, and 114Rh exhibit dominant spallation cross-sections, emphasizing their exceptional significance. [ABSTRACT FROM AUTHOR]

This study employs qualitative methodology, utilizing both secondary and primary data collection techniques to investigate radioactive contamination in Saudi Arabia's groundwater sources. Secondary data, encompassing academic studies, government reports, and international databases, provide a comprehensive understanding of existing contamination levels and trends in the Kingdom. Moreover primary data from field surveys across the country enhances this understanding by evaluating contamination levels in 500 wells distributed across five distinct regions. Academic studies revealed radionuclide concentrations below WHO's recommended limits in Jazan Province and highlighted the necessity of continuous monitoring due to uranium deposits. Additionally, Contaminant Transport Modeling (CTM) research trends showed an upsurge, delineating pivotal contributors and key focus areas for future studies. Publicly available data sources, including reports from government bodies and environmental organizations, indicated generally compliant contamination levels across Saudi Arabia, with exceptions in specific regions hosting uranium deposits. Moreover, research studies substantiated localized contamination exceeding safe limits, emphasizing the need for ongoing monitoring and remediation strategies. Primary data collection highlighted widespread radioactive contamination, with approximately 20% of samples exceeding WHO guidelines for gross alpha and beta activity and 10% surpassing limits for radium-226. Furthermore radon-222 levels, though generally below guidelines, showed elevations in certain areas. Identified sources of contamination encompass naturally occurring radioactive materials (NORMs), industrial activities and improper waste disposal. Mechanisms of contamination transport, including advection, diffusion, and sorption within groundwater, were delineated. Treatment strategies such as ion exchange, reverse osmosis, and aeration were proposed to mitigate radioactive contaminants. In summary, this study emphasizes the significant issue of radioactive contamination in Saudi Arabian groundwater, highlighting the need for continual monitoring, a comprehensive understanding of contamination sources and transport mechanisms, and the implementation of effective treatment strategies to safeguard public health and the environment. [ABSTRACT FROM AUTHOR]

The exposures of the lower member of Um Bogma Formation (Early Carboniferous) in a vast area east of Wadi Baba were studied in six localities. The member is dominated by argillaceous rocks in the western and southwestern occurrences, carbonates in the central sector of the area and sandstones at the east.These rock types, especially the carbonates in Allouga locality, consist of large assemblages of non-radioactive, radioactive and REEs- and base metals- bearing minerals of a mixed allogenic-authigenic and primary-secondary origin. Most of the allogenic minerals were inherited from unaltered and altered precursors in felsic igneous rocks. The results of extensive geochemical studies confirmed varying enrichment of the studied rocks in many trace and rare earth elements as well as base metals. The rocks in Allouga locality and, to a lesser extent, those in Talet Seliem and Abu Zarab have the highest potential as possible resources of these elements. Sequential extraction of Mn, Cu, Fe, Pb, U, Th, Y, La and Dy from five fractions revealed that these elements are exchangeable, bound to carbonates, iron and manganese oxides and organic matter and/or residual. The distributions of trace elements and REEs among the different rock types show variation based on their affinities to specific lithologies. The REEs generally show enriched patterns and negative Eu anomalies. U enrichment in rocks of this member is correlated with the occurrence of several types of uranyl silicate minerals. The co-existence of these minerals reflects variations in the activities of Ca, Mg, Cu and Pb. The hydrothermal activities related to the Red Sea extension were responsible for the oxidation of sulphides, alteration of primary minerals and genesis of Mn oxides, surficial uranyl and REEs mineralisations. Based on the obtained data, certain localities are recommended for future prospecting plans. [ABSTRACT FROM AUTHOR]

This paper reports on the development of stable tumor-specific gold nanoparticles (AuNPs) activated by neutron irradiation as a therapeutic option for the treatment of cancer with high tumor angiogenesis. The AuNPs were designed with different mono- or dithiol-ligands and decorated with different amounts of Arg-Gly-Asp (RGD) peptides as a tumor-targeting vector for αvβ3 integrin, which is overexpressed in tissues with high tumor angiogenesis. The AuNPs were evaluated for avidity in vitro and showed favorable properties with respect to tumor cell accumulation. Furthermore, the therapeutic properties of the [198Au]AuNPs were evaluated in vitro on U87MG cells in terms of cell survival, suggesting that these [198Au]AuNPs are a useful basis for future therapeutic concepts. [ABSTRACT FROM AUTHOR]

Various types of machine oil are used for analysis and utility equipment, and these organic liquid wastes are stored in nuclear facilities and laboratories due to a lack of appropriate treatment processes. Treatment of organic liquid waste is one of the principal tasks since radiolysis of organic material generates various hazardous products. Perfluoro oil, generally used in vacuum pumps, is difficult to decompose because of its chemical stability. Calcination of fluorine compounds is possible to generate toxic and corrosive gas products. In order to achieve complete mineralization of the organic liquid wastes, the application of a subcritical water reaction was examined. In this study, the effect of introducing a functional group into a perfluoro compound on its decomposition performance was experimentally evaluated. First, we carried out the transformation of perfluorohexane to perfluorohexyl iodide or perfluoroheptanoic acid based on reported procedures. Next, laboratory scale batch-wise decomposition tests with subcritical water on perfluorohexyl iodide and on perfluoro heptanoic acid were carried out. Analyses of degraded organic products remaining in the aqueous phase by atmospheric pressure ionization mass spectrometry and liquid chromatography-mass spectrometry were carried out. The decomposition products of each fluorine compound were identified, confirming that subcritical treatment is a promising treatment method.

In the present study, the heat activation and vacuum activation have been used to re-increase the adsorbed amount of Xe and Kr on activated charcoal for radioactive off-gas treatment systems in NPPs. There are, however, the dangers that the residual radioactive contaminants have been released into environment, and the charcoal has been poorly activated during the regeneration. Based on the adsorption properties of activated charcoal from other studies, the experimental on temperature, time, airflow, vacuum, and radioactivity in the environment, carried out in laboratories and nuclear power plants, have been applied as verify effectiveness of activation and radioactive material control. The final test results show that the water content of charcoal decreased by 4.03 % after 48-h heating at the gas flow of 180 N/m³ and 160 °C and 24-h vacuuming. In addition, the test controlled the residual radioactive contaminants by airflow adjustment and three-stage filtration. The developed activation processes based on heat and vacuum technology with supporting equipment, which are adapted to radioactive charcoal with different water contents for radioactive off-gas treatment systems, can be carried out online on nuclear power plant systems.

99Tc and 129I are two long-lived, highly soluble and mobile fission products that pose a long-term hazard. A proposed wasteform for the disposal of radio-iodine is iodovanadinite (Pb5(VO4)3I), an apatite-structured vanadate. In this investigation, a suite of potential iodovanadinite wasteforms designed for the co-disposal of Tc and I or the sole disposal of I were synthesised via hot isostatic pressing (with Mo as a surrogate for Tc). It was found that direct synthesis from oxide and iodide precursors was possible using hot isostatic pressing (HIPing). Increasing overpressure during HIPing was found to improve the density of the final product. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses indicated that the use of AgI as the source of iodine affected the formation of the target iodovanadinite phase and produced unfavourable phase assemblages. Here, we report the direct synthesis of Pb5(VO4)3I in a single step by hot isostatic pressing.

The objective of this work is to give a holistic overview of the groundwater quality in Qatar in terms of its radon levels and provide a radiological risk assessment of elevated radon levels on human health. This study covered the analysis of groundwater collected from various locations throughout Qatar and maps using ArcGIS followed by a radiological risk assessment of radon in Qatar. There is no extensive study reported to investigate radon activity levels in groundwater across Qatar and their health effects. The radon level measurements of the Qatari groundwater ranged between 2.7 ± 0.2 and 60.7 ± 13.4 Bq/L with a mean value of 20.6 Bq/L, which is greater than the US EPA's maximum contamination level (11 Bq/L). About 65% of the studied samples exceeded the US EPA's MCL guidelines. The mean total annual effective dose due to radon inhalation and ingestion was 0.056 mSv/y, which is below the WHO reference level of 0.1 mSv/y. The radon radiological risk study through inhalation and ingestion clearly revealed that the contribution of the inhalation dose was higher than the ingestion dose. [ABSTRACT FROM AUTHOR]

Copyright of Uranium Mining & Metallurgy is the property of Uranium Mining & Metallurgy Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

99Tc and 129I are two long-lived, highly soluble and mobile fission products that pose a long-term hazard. A proposed wasteform for the disposal of radio-iodine is iodovanadinite (Pb5(VO4)3I), an apatite-structured vanadate. In this investigation, a suite of potential iodovanadinite wasteforms designed for the co-disposal of Tc and I or the sole disposal of I were synthesised via hot isostatic pressing (with Mo as a surrogate for Tc). It was found that direct synthesis from oxide and iodide precursors was possible using hot isostatic pressing (HIPing). Increasing overpressure during HIPing was found to improve the density of the final product. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses indicated that the use of AgI as the source of iodine affected the formation of the target iodovanadinite phase and produced unfavourable phase assemblages. Here, we report the direct synthesis of Pb5(VO4)3I in a single step by hot isostatic pressing. [ABSTRACT FROM AUTHOR]

Copyright of Conservar Património is the property of Associacao Profissional de Conservadores-Restauradores de Portugal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The relative cross sections for radioactive negative ion production via double electron capture have been measured for collisions between a 40 keV projectile beam of uranium-238 and potassium vapor. This was performed at the collinear resonance ionization spectroscopy (CRIS) experiment at CERN-ISOLDE and is a step towards measuring the electron affinities (EAs) of elements that cannot be efficiently produced in negative ion sources at radioactive ion beam (RIB) facilities. This includes short-lived radioactive isotopes that have low production quantities and heavy and superheavy elements that systematically have smaller EAs than work functions of available ion source materials. Negative ions are particularly sensitive to electron–electron correlation effects, which make such studies ideal for benchmarking atomic structure models that go beyond the independent particle model. While the EAs of most light elements have been measured, experimental investigations on heavier elements, namely the actinides, remain scarce due to their radioactive nature and production difficulty. By developing negative ion production by charge exchange, we aim to make these studies feasible at RIB facilities. [ABSTRACT FROM AUTHOR]

A mesoporous silicate material (MS) was effectively synthesized and applied as a solid sorbent for removal of radioactive Sr(II) ions from aqueous solution. MS was characterized using different tools including N2 adsorption-desorption analysis, FT-IR, XRD and SEM. The synthesized material has crystalline, porous nature and exhibited a large surface area of about 905.18 m2 g−1. The uptake of Sr(II) ions onto MS was investigated under different batch experimental conditions involving pH, equilibrium time, sample weight and initial concentration of Sr(II) ions. About 98 % of Sr(II) radionuclides were uptaken at pH 12 in the first minute. Different isotherm models (Langmuir, Freundlich, Dubinin-Radushkevich and Temkin) were applied to analyze the obtained experimental sorption equilibrium data. The Langmuir isotherm model was aligned well with the sorption data. The maximum sorption capacity (Qmax) of MS towards strontium ions attained the value 0.991 mmol/g. The parameters (ΔG°, ΔH° and ΔS°) were calculated from thermodynamic study and their values showed that sorption process of Sr(II) ions on MS is strong, take place spontaneously, and considered as endothermic process. The synthesized MS had the ability to efficiently remove Sr(II) radionuclides even in the presence of Na+ and Ca2+ as competing cations in aqueous solution. Among the studied desorbing agents, CaCl2 was the best one for desorbing Sr(II) radionuclides loaded onto MS. The synthesized MS was reused for sorption of strontium up to four cycles with acceptable efficiency. [ABSTRACT FROM AUTHOR]

Radiation air dose rates near the Fukushima Daiichi Nuclear Power Plant (FDNPP) have been steadily decreasing over the past eight years since the release of radioactive elements in March 2011. Currently, the radiation monitoring program is expected to transition to long-term monitoring after most of the remediation activities are completed. The main long-term monitoring objectives are to (1) confirm the continuing reduction of contaminant and hazard levels, (2) provide assurance for the public, (3) accumulate the basic datasets for scientific knowledge and future preparation, and (4) detect changes or anomalies in contaminant mobility (if they occur), or any unexpected processes or events. In this work, we have developed a methodology for optimizing the monitoring locations of radiation air dose-rate monitoring. Our approach consists of three steps in order to determine monitoring locations in a systematic manner: (1) prioritizing the critical locations, such as schools or regulatory requirement locations, (2) diversifying locations that cover the key environmental controls that are known to influence contaminant mobility and distributions, and (3) capturing the heterogeneity of radiation air-dose rates across the domain. For the second step, we use a Gaussian mixture model to identify the representative locations among multiple environmental variables, such as elevation and land-cover types. For the third step, we use a Gaussian process model to capture and estimate the heterogeneity of air-dose rates across the domain. Employing an integrated dose-rate map derived from Bayesian geostatistical methods as a reference map, we distribute the monitoring locations in such a way as to capture the heterogeneity of the reference map. Our results have shown that this approach allows us to select monitoring locations in a systematic manner such that the heterogeneity of air dose rates is captured by the minimal number of monitoring locations.

The processing of sediment to accurately characterize the spatially-resolved depth profiles of geophysical and geochemical properties along with signatures of microbial density and activity remains a challenge especially in complex contaminated areas. This study processed cores from two sediment boreholes from background and contaminated core sediments and surrounding groundwater. Fresh core sediments were compared by depth to capture the changes in sediment structure, sediment minerals, biomass, and pore water geochemistry in terms of major and trace elements including pollutants, cations, anions, and organic acids. Soil porewater samples were matched to groundwater level, flow rate, and preferential flows and compared to homogenized groundwater-only samples from neighboring monitoring wells. Groundwater analysis of nearby wells only revealed high sulfate and nitrate concentrations while the same analysis using sediment pore water samples with depth was able to suggest areas high in sulfate- and nitrate-reducing bacteria based on their decreased concentration and production of reduced by-products that could not be seen in the groundwater samples. Positive correlations among porewater content, total organic carbon, trace metals and clay minerals revealed a more complicated relationship among contaminant, sediment texture, groundwater table, and biomass. The fluctuating capillary interface had high concentrations of Fe and Mn-oxides combined with trace elements including U, Th, Sr, Ba, Cu, and Co. This suggests the mobility of potentially hazardous elements, sediment structure, and biogeochemical factors are all linked together to impact microbial communities, emphasizing that solid interfaces play an important role in determining the abundance of bacteria in the sediments.

تشخيص الحالة الحالية لأعمدة الجرانيت المتبقية وطرق العلاج المقترحة في منطقة ميريت آمون ، أخميم ، مصر [AR] تم استخدام الجرانيت في المسلات والمباني والتماثيل في مصر القديمة ، وتمت دراسة أعمدة الجرانيت باستخدام [PLM] و [XRD] و XRF]] و [SEM]، وأظهرت نتائج الدراسة أن المياه الأرضية الممزوجة بمياه الصرف الصحي تسببت في تلف الجرانيت ، و يعتمد الضرر أيضًا على قدرة المياه الأرضية على الارتفاع من خلال مسام وشقوق الجرانيت نتيجة عوامل التلف السابقة وعند الارتفاع يكون منسوب المياه الجوفية -0. 5 م والنشاط الإشعاعي في الهواء والماء والتربة والصخور وأشعة الشمس في الموقع الأثري له دور مهم في التلف ، بالإضافة إلى النشاط الإشعاعي الناتج عن الاستخدامات في الحياة مما يزيد من تأثير النشاط الإشعاعي المؤثر على تلف الحبيبات المعدنية للجرانيت في الموقع ، والتي تؤدي إلى تسريع عمليات التلف ، كما تمت دراسة المواد الموصى بها و التي يمكن استخدامها لتقوية ومعالجة الجرانيت. [EN] Granite was used in obelisks, buildings, and statues in ancient Egypt. Granite columns were studied using [PLM], [XRD], [XRF] and [SEM].The results of the study showed that the ground water mixed with sewage water caused granite damage, which also depends on the ability of ground water to rise through the pores and cracks of the granite as a result of previous damage factors and rise the ground water level is -0.5 m. The radioactivity in the air, water, soil, rocks and sunlight at the archaeological site has an important role in the damage, in addition to the radioactivity resulting from the uses in life, which increases the effect of the radioactivity affecting the mineral grains of the granite at the study site, which leads to acceleration of deterioration processes. Additionally, the recommended materials that can be used to consolidate and treat granite were studied.

Insights at the microscopic level of the process of radiocesium adsorption and interaction with clay mineral particles have improved substantially over the past several years, triggered by pressing social issues such as management of huge amounts of waste soil accumulated after the Fukushima Dai-ichi nuclear power plant accident. In particular, computer-based molecular modeling supported by advanced hardware and algorithms has proven to be a powerful approach. Its application can now generally encompass the full complexity of clay particle adsorption sites from basal surfaces to interlayers with inserted water molecules, to edges including fresh and weathered frayed ones. On the other hand, its methodological schemes are now varied from traditional force-field molecular dynamics on large-scale realizations composed of many thousands of atoms including water molecules to first-principles methods on smaller models in rather exacting fashion. In this article, we overview new understanding enabled by simulations across methodological variations, focusing on recent insights that connect with experimental observations, namely: 1) the energy scale for cesium adsorption on the basal surface, 2) progress in understanding the structure of clay edges, which is difficult to probe experimentally, 3) cesium adsorption properties at hydrated interlayer sites, 4) the importance of the size relationship between the ionic radius of cesium and the interlayer distance at frayed edge sites, 5) the migration of cesium into deep interlayer sites, and 6) the effects of nuclear decay of radiocesium. Key experimental observations that motivate these simulation advances are also summarized. Furthermore, some directions toward future solutions of waste soil management are discussed based on the obtained microscopic insights.

In this study, we quantify the temporal changes of air dose rates in the regional scale around the Fukushima Dai-ichi Nuclear Power Plant in Japan, and predict the spatial distribution of air dose rates in the future. We first apply the Bayesian geostatistical method developed by Wainwright et al. (2017) to integrate multiscale datasets including ground-based walk and car surveys, and airborne surveys, all of which have different scales, resolutions, spatial coverage, and accuracy. This method is based on geostatistics to represent spatial heterogeneous structures, and also on Bayesian hierarchical models to integrate multiscale, multi-type datasets in a consistent manner. We apply this method to the datasets from three years: 2014 to 2016. The temporal changes among the three integrated maps enables us to characterize the spatiotemporal dynamics of radiation air dose rates. The data-driven ecological decay model is then coupled with the integrated map to predict future dose rates. Results show that the air dose rates are decreasing consistently across the region. While slower in the forested region, the decrease is particularly significant in the town area. The decontamination has contributed to significant reduction of air dose rates. By 2026, the air dose rates will continue to decrease, and the area above 3.8 μSv/h will be almost fully contained within the non-residential forested zone.

The shielding effectiveness of concretes with different aggregate and cement composition was determine by shielding Co-60 gamma radiation source at center for energy research and training (CERT), Ahmadu Bello University Zaria with block concretes that contain aggregate 5.00 mm, 10.00 mm and 15.00 mm respectively. A concrete with thickness of 0.0762 m with dimension of 0.30 m x 0.30 m was formed from each of the aggregates with equal volume of sharp sand and cement. The result revealed the calculated mean free path (MFP) with values within a range of (0.033 to 0.070) m for samples DG (Dangote) and BU (BUA), mass attenuation coefficient (MAC) and half value layer (HVL) values within a range of (1.9 to 2.75) x 10-3 m2/kg and (0.023 to 0.049) m respectively. This shows that samples DG1, DG2 and DG3 have better shielding ability due to its lower MAC, MFP and HVL compared to samples BU1, BU2 and BU3.

Study objective: The aim of this study was to evaluate the performance of indocyanine green (ICG) compared to that of the gold standard 99mtechnetium (99mTc-nanocolloids) in detecting sentinel lymph nodes (SLN) in early vulvar cancer. Material and Methods: A single-center retrospective cohort study comparing SLN detection by 99mTc-nanocolloids and ICG was performed in patients presenting early vulvar cancer (T1/2), with clinically negative nodes. All SLN showing a radioactive and/or fluorescent signal were resected. The primary endpoints were the sensitivity, positive predictive value (PPV) and false negative (FN) rate of ICG in detecting SLN compared to 99mTc-nanocolloids. Results: Thirty patients were included and 99 SLN were identified in 43 groins. Compared to 99mTc-nanocolloids, ICG had a sensitivity of 80.8% (95% CI [72.6; 88.6%]), a PPV of 96.2% (95% CI [91.8; 100%]) and a FN rate of 19.1% in detecting SLN. Seventeen (17.1%) infiltrated (positive) SLN were identified out of the 99 SLN detected. Compared to 99mTc-nanocolloids, ICG showed a sensitivity of 82.3% (95% CI [73.1; 91.5%]), a PPV of 100% and a FN rate of 17.6% (3/17) in detecting infiltrated SLN. Conclusion: Despite its many advantages, ICG cannot be used as the sole tracer for the detection of SLN in early vulvar cancer and should be employed in conjunction with 99mTc-nanocolloids.

Herein, we report a new strategy for the rapid removal of uranium-containing contaminants from metal surfaces, and it relies on decontaminants made of NaOH-based molten salts. The addition of Na2CO3 and NaCl to NaOH exhibited superior decontamination performance, with a decontamination rate of 93.8% within 12 min, outdoing the performance of the single NaOH molten salt. The experimental results demonstrated that the synergistic effects between CO32− and Cl− promoted the corrosion efficiency of the molten salt on the substrate, which accelerated the decontamination rate. Additionally, benefiting from the optimization of the experimental conditions by the response surface method (RSM), the decontamination efficiency was improved to 94.9%. Notably, it also showed remarkable results in the decontamination of specimens containing different uranium oxides at low and high levels of radioactivity. This technology is promising for broadening the path in rapid decontamination of radioactive contaminants on metal surfaces. [ABSTRACT FROM AUTHOR]

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In this paper, a nano functional agent HXG-36-8 without harmful substances and radiation source was prepared. By means of SEM, XRD, EDS, XRF, eye irritation test, skin irritation test, acute oral toxicity test, antibacterial test and antiviral test, the micromorphology observation, phase structure analysis, composition analysis, biological toxicity test, antibacterial test and antiviral test were carried out. Hxg-36-8 has flake nanoscale microscopic morphology and crystal structure of wurtzite zinc oxide. It has no irritation to rabbit eyes and rabbit skin and is actually nontoxic. In addition, the antibacterial product prepared with HXG-36-8 as antibacterial agent has an antibacterial rate of 99.0% against Escherichia coli and an anti-novel coronavirus activity rate of over 98.87%. The results showed that the functional agent is safe, nontoxic, has good antibacterial and antiviral function, can be used in all kinds of products in contact with human body, including clothing, protective articles, dental ceramic materials, etc. [ABSTRACT FROM AUTHOR]

Introduction: Hilar cholangiocarcinoma (HC) is the leading cause of hilar biliary obstruction. Radioactive stent insertion has been utilized extensively for inoperable HC patients. Aim: To assess the relative clinical outcomes of inoperable HC patients who underwent either normal or radioactive stent insertion. Material and methods: This single-center, prospective, randomized, open-label study enrolled 90 inoperable HC patients from April 2021 to March 2022 and randomly assigned them to normal or radioactive stent groups (n = 45/group), with clinical data then being compared between these groups. Results: Technical success rates in the normal and radioactive stent insertion groups were 93.3% and 97.9%, respectively (p = 1.000), and clinical success rates were similarly consistent in both groups (95.3% vs. 97.7%, p = 0.983). Individuals in the radioactive stent group exhibited significantly longer median stent patency as compared to the normal stent group (195 days vs. 115 days, p < 0.001), and median overall survival (OS) was also significantly increased in the normal stent group (242 days vs. 125 days, p = 0.002). In the normal stent insertion group, 6 (14.3%) and 5 (11.9%) patients experienced early and late postoperative complications, respectively. Additionally, early and late postoperative complications impacted 7 (16.3%) and 8 (18.6%) patients in the radioactive stent insertion group, respectively. Complication rates were comparable in these 2 patient groups. Conclusions: Radioactive stent insertion represents a safe and effective strategy for patients with inoperable HC, potentially contributing to prolonged stent patency and OS relative to normal stent insertion. [ABSTRACT FROM AUTHOR]

This study investigates the potential impact of climate change on residual contaminants in vadose zones and groundwater. We assume that the effect of climate changes can be represented by perturbations in the natural recharge through the aquifer system. We perform numerical modeling of unsaturated/saturated flow and transport and consider different performance metrics: contaminant concentrations at observation wells and contaminant export at the site's boundary. We evaluate the effect of increasing and decreasing recharge as well as the impact of potential failure of surface capping structures employed to immobilize vadose zone contaminants. Our approach is demonstrated in a real case study by simulating transport of non-reactive radioactive tritium at the U.S. Department of Energy's Savannah River Site. Results show that recharge changes significantly affect well concentrations: after an initial slight dilution we identify a significant concentration increase at different observation wells some years after the recharge increase and/or the cap failure, as a consequence of contaminants' mobilization. This effect is generally emphasized and occurs earlier as the recharge increases. Under decreased aquifers' recharge the concentration could slightly increase for some years, due to a decrease of dilution, depending on the magnitude of the negative recharge shift. We identify trigger levels of recharge above which the concentration/export breakthrough curves and the time of exceedance of the Maximum Contaminant Level for tritium are remarkably affected. Moreover, we observe that the contaminant export at the control plane, identified as the risk pathway to the downgradient population, may only be minimally affected by shifts in the natural recharge regime, except for some extreme cases. We conclude that more frequent sampling and in-situ monitoring near the source zone should be adopted to better explain concentrations' anomalies under changing climatic conditions. Moreover, the maintenance of the cap is critical not only to sequester residual contaminants in the vadose zone, but also to reduce the uncertainty associated with future precipitation changes. Finally, realistic flow and transport simulations achieved through proper calibration processes, rather than conservative modeling, should be adopted to identify non-trivial trade-offs which enable better allocation of resources towards reducing uncertainty in decision making.

Uranium (U) groundwater contamination is a major concern at numerous former mining and milling sites across the Upper Colorado River Basin (UCRB), USA, where U(IV)-bearing solids have accumulated within naturally reduced zones (NRZs). Understanding the processes governing U reduction and oxidation within NRZs is critical for assessing the persistence of U in groundwater. To evaluate the redox cycling of uranium, we measured the U concentrations and isotopic compositions (δ238U) of sediments and pore waters from four study sites across the UCRB that span a gradient in sediment texture and composition. We observe that U accumulation occurs primarily within fine-grained (low-permeability) NRZs that show active redox variations. Low-permeability NRZs display high accumulation and low export of U, with internal redox cycling of U. In contrast, within high-permeability NRZs, U is remobilized under oxidative conditions, possibly without any fractionation, and transported outside the NRZs. The low δ238U of sediments outside of defined NRZs suggests that these reduced zones act as additional U sources. Collectively, our results indicate that fine-grained NRZs have a greater potential to retain uranium, whereas NRZs with higher permeability may constitute a more-persistent but dilute U source.