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The growing concern over micropollutants in aquatic ecosystems motivates the development of electrochemical membrane reactors (EMRs) as a sustainable water treatment solution. Nevertheless, the intricate interplay among adsorption/desorption, electrochemical reactions, and byproduct formation within EMR complicates the understanding of their mechanisms. Herein, the degradation of micropollutants using an EMR equipped with carbon nanotube membrane are investigated, employing isotope-labeled steroid hormone micropollutant. The integration of high-performance liquid chromatography with a flow scintillator analyzer and liquid scintillation counting techniques allows to differentiate hormone removal by concurrent adsorption and degradation. Pre-adsorption of hormone is found not to limit its subsequent degradation, attributed to the rapid adsorption kinetics and effective mass transfer of EMR. This analytical approach facilitates determining the limiting factors affecting the hormone degradation under variable conditions. Increasing the voltage from 0.6 to 1.2 V causes the degradation dynamics to transition from being controlled by electron transfer rates to an adsorption-rate-limited regime. These findings unravels some underlying mechanisms of EMR, providing valuable insights for designing electrochemical strategies for micropollutant control. Pervasive micropollutants in aquatic environments pose significant threats to global water supply safety. Here, authors achieved permeate concentrations below the detection limit (2.5 ng/L) using a CNT-based electrochemical membrane, with the contributions of adsorption and degradation distinguished. [ABSTRACT FROM AUTHOR]

The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident created large stockpiles of tritium containing cooling water, which is to be gradually released into the Pacific Ocean, gaining attention from surrounding countries, environmental groups, and local residents concerned with the possibility of increasing tritium concentrations in the water and food cycle. Establishing baseline concentration levels and monitoring tritium immission values are important for assuring public safety, providing data for scientific research and risk communication. Tritium concentrations in the environment are very low; therefore, tritium measurements require enrichment in order to estimate the radiation exposure from drinking water intake and provide information on the water cycle. Natural water samples were collected at Tomioka Town located south of the FDNPP. Samples were distilled, enriched by electrolysis, and re-distilled using an improved SPE method to preconcentrate tritium to measureable levels. Tritium concentrations were determined by a low-background liquid scintillation counter. The observed tritium concentrations were relatively low, rainwater had a mean and SD value of 0.40 ± 0.13 Bq/L, and freshwater samples showed similar concentrations, while brackish coastal water samples were below 0.13 ± 0.02 Bq/L. The observed tritium concentrations in this study are considered safe as effective doses based on annual drinking water intake; however, continous monitoring is necessary to assure public safety. [ABSTRACT FROM AUTHOR]

The new electrolytic enrichment system with compact glass cell was designed. Three (Ni–Fe–Ni) electrodes are used, and electrolysis is carried out at a rate of 2.45 g per h with constant current density of 120 mA per cm2. This enrichment system allows the enrichment for small, limited sample volumes (e.g. Tritiated Water (HTO) recovered from air). With an initial water volume of 100 ml, the tritium enrichment factor of 7 within 2 days and a detection limit of 0.12 Bq per L can be obtained by Liquid Scintillation Counter (LSC) measurement for 1000 minutes, which is better than the direct measurement with 50 ml sample water using large vial. It is also possible to perform the high enrichment process. The initial sample volume of 700 ml enriched for 12 days by manual refilling yields a tritium enrichment factor of around 43 and detection limit of 0.02 Bq per L for 1000 minutes of LSC measurement. [ABSTRACT FROM AUTHOR]

This article mainly discusses tritium concentrations in monthly precipitation at Hiroshima City during 2021. The tritium concentrations, which were measured with a low background liquid scintillation counter, fluctuated from 0.16 to 0.78 Bq L−1. Additionally, hydrogen and oxygen stable isotopes and ionic species were measured in order to characterize precipitation, and their trends including tritium concentrations were compared with data collected in other regions of Japan in previous studies. Although the results showed the characteristics of precipitation were similar to those observed in the other regions, the tritium concentrations were found to be contrary to behavior expected from the latitude effect and some of the observed ionic components were suggested to be continental in origin. Since these results are not common at other sites in Japan, the tritium concentration in the westernmost region of Honshu, including Hiroshima City, may be influenced by Asian continental influences. [ABSTRACT FROM AUTHOR]

Soil contamination by the munition explosive residues of 2,4,6-trinitrotoluene (TNT) and its metabolites resulting primarily from military operations has been identified as a threat to human health and ecosystems. Biodegradation by native plants to remove this hazardous compound or reduce its toxicity is considered a cost-effective and environmentally sound approach for the cleanup or restoration of TNT-contaminated soils. This study aims to investigate the TNT biodegradation and kinetics by two selected native grasses in the species-specific rhizosphere soils through growth chamber experiments. Native eastern gamma grass (Tripsacum dactyloides) and switchgrass (Panicum virgatum L.) were grown in soil spiked with 14C-TNT for 8 weeks. The 14C-TNT degradation and degradative metabolite profile in the rhizosphere soils were determined by liquid scintillation counter and high-performance liquid chromatography, respectively. The results indicated that both native grass species significantly enhanced the TNT degradation in the rhizosphere soils as compared with the control rhizosphere soils. More than 95% of the applied 14C-TNT was degraded in the first 7 days, and the rate then reached a steady state afterward, but less than 10% of the TNT applied was completely mineralized and transformed into CO2. The degradative reaction was found to follow second-order kinetics. Six major TNT degradative metabolites have been detected and identified in the rhizosphere soils. Overall, switchgrass appeared more effective for biodegrading TNT than eastern gamma grass. This research demonstrated that the native grass species, especially switchgrass, has the potential to mitigate the adverse human health and ecological risks of TNT-contaminated sites and can be considered an environmentally friendly, sustainable approach to safeguarding human health from TNT contamination. [ABSTRACT FROM AUTHOR]

Objectives: This work aims to establish a dataset of ratios between tissue free water tritium (TFWT) and organically bound tritium (OBT) (containing both exchangeable and non-exchangeable OBT) in different types of seafood from Zhejiang province, China, thus to provide references for rapid screening of potential contamination of tritium in biological samples. Methods: Five types of seafood (fish, prawn, mussel, crab and kelp) were collected from Jiaxing, Ningbo, Zhoushan, Taizhou and Wenzhou city in Zhejiang Province in 2022, and measured for TFWT and OBT using tube furnace combustion system and liquid scintillation counting. Results: The observed activity concentrations of TFWT and OBT in this study were within the range of 1.01-10.09 Bq/L and 0.51-7.61 Bq/L, respectively. No significant difference in OBT/TFWT ratio was observed among different types of seafood (p > 0.05), among the geographic distribution of the five cities (p > 0.05), nor among the area of coastline, fishing ground and island (p > 0.05). Additionally, there was no significant difference in the OBT/TFWT ratio between seafood from area with and without nuclear power plant operation (p > 0.05). The mean OBT/TFWT ratio of fish, prawn, mussel, crab and kelp was 0.37 ± 0.19, 0.48 ± 0.27, 0.63 ± 0.33, 0.82 ± 0.50, and 0.64 ± 0.37, respectively. The mean and range of OBT/TFWT ratios were 0.59 ± 0.37 and 0.15-2.09 in all seafood collected from the five cities in Zhejiang Province, respectively. Conclusions: Our results indicate that tritium in seafood from coastal cities in Zhejiang Province is at the background level, and the operation of nuclear power plants in the province has no notable impact on the radioactivity levels of tritium in local marine biota. This study filled the gap in OBT/TFWT ratios in seafood, which provides new dataset for rapid detection of tritium contamination in nuclear emergencies. [ABSTRACT FROM AUTHOR]

The article discusses the findings from the Kosilovo mire in north-western Russia, focusing on the pollen data and sediment description. The mire is located in a temperate continental climate zone with mixed coniferous-broadleaved forests. The sediment core collected from the mire revealed changes in vegetation over the past 10,000 years, indicating shifts in tree species composition and climate conditions. The study also highlights the impact of human activity on the mire ecosystem. [Extracted from the article]

Studying groundwater renewal time is a valuable tool to deepen the comprehension of sustainable groundwater resources specific to arid regions. Tritium is a radioactive isotope of hydrogen often used as an environmental tracer to study groundwater renewal time. The present work reports groundwater renewal times by the environmental tracer tritium to understand sustainable water resources in arid regions. First, groundwater samples were collected from wells in northeastern arid regions of Saudi Arabia. Then, an electrolysis process was employed to significantly increase the tritium level from twenty-five to thirty times the original concentration. Subsequently, the enriched water was analyzed using a liquid scintillation counter under optimized measurement conditions to determine the tritium concentration precisely. Two internationally recognized tritium laboratories conducted independent assessments to validate the estimated tritium levels. The verified tritium concentration was then used to estimate the groundwater renewal time using the Morgenstern and Pimenta curves. The results suggest that most of the monitored wells in the surveyed areas are more than a century old. Conversely, a few monitoring wells exhibit renewal times of several hundred years and may be considered nonrenewable water sources. These studies help to understand the geochemical characteristics of arid regions to ensure the sustainable management and protection of groundwater resources. [ABSTRACT FROM AUTHOR]

Yttrium-90 (90Y) microsphere radioembolization is a promising internal therapy for treatment of hepatic tumors. Development of a precise method for measuring the activity of 90Y in blood samples is needed to facilitate preclinical safety assessment of drugs. This paper presents the development of a triple-to-double coincidence ratio (TDCR) Cherenkov counting method for quantifying blood 90Y activity. The impact of heating temperature and the quantities of nitric acid and H2O2 on wet oxidation of blood were studied for rapid sample preparation. Elevated heating temperatures and the addition of concentrated nitric acid expedited blood decolorization and effectively suppressed chemiluminescence interference. The addition of H2O2 also accelerated blood decomposition while mitigating sample color quenching. The digested samples were counted using a Hidex 300SL liquid scintillation counter for 5 minutes, and a minimum detectable activity of 0.31 kBq/L was achieved with the region of interest (ROI) analysis window set at 80–300 channels. The method was validated using whole blood samples spiked with varying activities of 90Y in the range of 3.37–51.15 kBq/L. [ABSTRACT FROM AUTHOR]

Carbon-14 and tritium are important radionuclides to be present in gaseous effluents of some nuclear power plants types. Tritium being usually included in gaseous effluents bearing carbon-14, the influence of its presence in the analyzes to be done must carefully be taken into account. When Liquid Scintillation Counting method is used, this influence can't be completely eliminated by selecting different channels only for measuring carbon-14. In this paper, experimental verification of the influence of tritium on the carbon-14 measurements also miscibility of samples, detection efficiency and measurement precision were studied. [ABSTRACT FROM AUTHOR]

The Centers for Disease Control and Prevention (CDC) Radiation Laboratory's primary mission is to provide laboratory support for an effective and efficient response to public health radiological emergencies. The laboratory has developed methods for several radiological threat agents, including Iridium-192 (Ir-192). Ir-192 can be analyzed via its gamma energy through analytical methods such as High Purity Germanium (HPGe) and its beta energy through Liquid Scintillation Counting (LSC). In this work, we present and compare HPGe and LSC rapid response methods for Ir-192 quantification. Both methods show the reasonable results and can be used in emergency situations. [ABSTRACT FROM AUTHOR]

Mined rock phosphate is expected to become a scarce resource within the next few decades as global phosphorus (P) deposits are declining. As a result, mineral P fertilizer will be less available and more expensive. Therefore, improved knowledge is needed on other P resources, for example, apatite fertilizers derived from the by‐products of iron mining. Forestry is a potential future consumer of apatite‐rich products with the aim of obtaining more wood per hectare. The actual P availability in apatite to plants has so far been barely quantified. We therefore examined tree P uptake using 33P apatite under chamber‐grown and outdoor conditions. We examined the P uptake for the two main conifer species spruce (Picea abies) and pine (Pinus sylvestris) used in Fenno‐Scandinavian forestry. We synthesized 33P‐enriched apatite and applied it to mesocosms with growing seedlings of spruce and pine. The P uptake from 33P‐labelled hydroxylapatite was subsequently traced by (bio)imaging of radioactivity in the plants and by liquid scintillation counting (LSC) upon destructive harvest in all plant fractions (leaves, stem and roots) and rhizosphere soil. Two climatic conditions were compared, one at natural outdoor conditions and one set as 5°C warmer than the climate record from the previous years. Plant P uptake from 33P‐labelled hydroxylapatite was enhanced in chamber‐grown compared with outdoor seedlings for both tree species. This uptake was manifested in the clear radioactive images obtained over ca. 1 month after soil apatite application. Furthermore, all aboveground plant fractions of both spruce and pine seedlings showed a higher P uptake in warmer than colder daytime environments. The observed quantities and rates of P uptake from 33P‐labelled hydroxylapatite by spruce (18 Bq g−1 hour−1) and pine (83 Bq g−1 hour−1; averages in chamber condition) are as to our knowledge unique observations. Natural forest soils in Sweden are often P‐poor. Our research suggests that apatite‐based P fertilization of spruce and pine forests can increase wood production by overcoming any existing P limitation. [ABSTRACT FROM AUTHOR]

The liquid scintillation counting based triple to double coincidence ratio (TDCR) method is a widely employed, direct activity determination technique to standardize pure beta emitters. An "FPGA-based standalone, portable TDCR system" is developed for absolute activity measurement of pure beta-emitting radionuclides. The system has a local 7″ touchscreen display to provide an intuitive GUI for operating the standalone instrument. The portable system will boost the capabilities of users in the field by providing a reference measurement method of radionuclide metrology. In nuclear medicine, the portable system will enable them to calibrate short-lived radionuclides within the dose-administering facility and avoid transporting radioactive sources to standardizing laboratories. The system's performance is evaluated by comparing the activity determination results of 14C, 204Tl and 147Pm radionuclides with the ones from the CIEMAT/NIST method. The comparison shows that the activity measurement results from the system are closely aligned with those obtained using the CIEMAT/NIST method within the uncertainty limits. In this paper, the system's performance evaluation is presented. [ABSTRACT FROM AUTHOR]

This article explores the role of l-arginine transport in the survival of Leishmania donovani, a parasite that causes Indian visceral leishmaniasis (VL), within macrophages. The study found that the availability of extracellular l-arginine is crucial for the survival of the parasite inside macrophages. The researchers also discovered that the CAT-2 isoform of the cationic amino acid transporter is associated with l-arginine transport in infected macrophages. The study suggests that targeting l-arginine metabolism and l-arginine-metabolizing enzymes could be a potential therapeutic strategy for treating VL. [Extracted from the article]

A cost-effective method for uranium measurements in soil, utilizing a Liquid Scintillation Counter with an extraction system and alpha/beta discrimination, has been developed. The study explores the method's applicability and validity in assessing uranium levels in soil and yellowcake samples. The scintillation cocktail achieves high capacity, ensuring 100% counting efficiency and a 98.6% extractive yield, with a 0.929 mg/g detection limit. Validation involves estimating uranium concentrations in certified reference materials and ore samples from different Jordanian locations. The results are comparable to measurements obtained through gamma spectroscopy, ICP-MS, and alpha spectroscopy techniques. [ABSTRACT FROM AUTHOR]

A portable liquid scintillation counting system has been used as a rapid screening tool for radiological characterization and in situ measurements of aqueous samples. The methodology was standardized based on the Pulse Length Index for gross α and gross β activity determinations in aqueous solutions by means of a portable Liquid Scintillation Counter (LSC). This single compact PMT system yielded precise results for aqueous test samples, which were validated against a conventional HIDEX 300SL LSC system. The sensitivity of the portable LSC for gross measurements was investigated thoroughly for various combinations of scintillation cocktails and sample proportions, and found to be well below the Operational Intervention Levels (OILs) recommended by Atomic Energy Regulatory Board (AERB) during radiation emergency scenarios. Gross α- and β-activity measurements by means of the portable LSC system have shown this procedure to be effective for preliminary screening and evaluating the total radioactivity in aqueous samples during such radiation emergencies. [ABSTRACT FROM AUTHOR]

In this work the distribution coefficients (D) of polonium between 0.1 mol dm−3 TOPO/toluene; TOPO/cyclohexane; TBP/toluene and TBP/cyclohexane and aqueous solutions of inorganic acids (HCl, HNO3, H2SO4 and H3PO4) were determinated. The molarities of inorganic acids were between 0.5 and 12.0 mol dm−3. The activity of extracted Po-209 was measured by means of liquid scintillation counting. The best result was obtained for TOPO/toluene and 2 mol dm−3 H2SO4 system (D = 62 ± 9). The most stable conditions of extraction were found for TOPO/toluene-HCl system. [ABSTRACT FROM AUTHOR]

The aim of this study was to test two potential tritium determination methods (with and without electrolysis enrichment) suitable for low-level measurements. Both methodologies were applied to water samples from the Baltic Sea and ten Polish rivers providing new data on tritium activity concentration. Optimization steps carried out to the standard method lowered minimum detectable activity concentration (MDC) from 3.1 to 1.8 Bq L–1 (at 95% confidence level) enabling to apply it to environmental water samples. However, electrolytic enrichment method of MDC of 0.20 Bq L–1 provided more accurate results for tritium activity concentration in surface waters. [ABSTRACT FROM AUTHOR]

Among natural radionuclides, 226Ra and 228Ra intake can contribute considerably to radiological dose. Liquid scintillation counting offers a reliable and sensitive method for measurement in environmental (water) and biological (urine) matrices. While the determination of 226Ra in water is quite simple, its determination in urine requires a suitable radiochemical procedure. In both cases an indirect measurement of daughter 222Rn (with 218Po and 214Po) in secular equilibrium allows to determine 226Ra activity. Moreover, in presence of anthropogenic radionuclides, a sequential separation of 228Ra and 90Sr in water has been developed, isolating daughters 228Ac and 90Y in secular equilibrium in the same vial. [ABSTRACT FROM AUTHOR]

Environmental radiochemistry is a key pillar of the education of nuclear engineering students and young professionals. Teaching the fundamentals of this multidisciplinary field is best performed also through well-designed hands-on experiments. A simple and fast radiochemical procedure has been developed to determine uranium in tap water by liquid scintillation counting. The proposed method provides reliable and repeatable results, with accuracy and precision within 5%. It can be proficiently executed by undergraduate students, who have appreciated the engagement and got acquainted with standard analysis protocols, from sample collection and manipulation to radiometric measure and data analysis. [ABSTRACT FROM AUTHOR]

The inflammatory corpuscle recombinant absents in melanoma 2 (AIM2) and cholesterol efflux protein ATP binding cassette transporter A1(ABCA1) have been reported to play opposing roles in atherosclerosis (AS) plaques. However, the relationship between AIM2 and ABCA1 remains unclear. In this study, we explored the potential connection between AIM2 and ABCA1 in the modulation of AS by bioinformatic analysis combined with in vitro experiments. The GEO database was used to obtain AS transcriptional profiling data; screen differentially expressed genes (DEGs) and construct a weighted gene co-expression network analysis (WGCNA) to obtain AS-related modules. Phorbol myristate acetate (PMA) was used to induce macrophage modelling in THP-1 cells, and ox-LDL was used to induce macrophage foam cell formation. The experiment was divided into Negative Control (NC) group, Model Control (MC) group, AIM2 overexpression + ox-LDL (OE AIM2 + ox-LDL) group, and AIM2 short hairpin RNA + ox-LDL (sh AIM2 + ox-LDL) group. The intracellular cholesterol efflux rate was detected by scintillation counting; high-performance liquid chromatography (HPLC) was used to detect intracellular cholesterol levels; apoptosis levels were detected by TUNEL kit; levels of inflammatory markers (IL-1β, IL-18, ROS, and GSH) were detected by ELISA kits; and levels of AIM2 and ABCA1 proteins were detected by Western blot. Bioinformatic analysis revealed that the turquoise module correlated most strongly with AS, and AIM2 and ABCA1 were co-expressed in the turquoise module with a trend towards negative correlation. In vitro experiments demonstrated that AIM2 inhibited macrophage cholesterol efflux, resulting in increased intracellular cholesterol levels and foam cell formation. Moreover, AIM2 had a synergistic effect with ox-LDL, exacerbating macrophage oxidative stress and inflammatory response. Silencing AIM2 ameliorated the above conditions. Furthermore, the protein expression levels of AIM2 and ABCA1 were consistent with the bioinformatic analysis, showing a negative correlation. AIM2 inhibits ABCA1 expression, causing abnormal cholesterol metabolism in macrophages and ultimately leading to foam cell formation. Inhibiting AIM2 may reverse this process. Overall, our study suggests that AIM2 is a reliable anti-inflammatory therapeutic target for AS. Inhibiting AIM2 expression may reduce foam cell formation and, consequently, inhibit the progression of AS plaques. [ABSTRACT FROM AUTHOR]

Cannabidiol is a major component of cannabis but without known psychoactive properties. A wide range of properties have been attributed to it, such as anti-inflammatory, analgesic, anti-cancer, anti-seizure and anxiolytic. However, being a fairly new compound in its purified form, little is known about cannabidiol brain entry, especially during development. Sprague Dawley rats at four developmental ages: embryonic day E19, postnatal day P4 and P12 and non-pregnant adult females were administered intraperitoneal cannabidiol at 10 mg/kg with [3H] labelled cannabidiol. To investigate the extent of placental transfer, the drug was injected intravenously into E19 pregnant dams. Levels of [3H]-cannabidiol in blood plasma, cerebrospinal fluid and brain were estimated by liquid scintillation counting. Plasma protein binding of cannabidiol was identified by polyacrylamide gel electrophoresis and its bound and unbound fractions measured by ultrafiltration. Using available RNA-sequencing datasets of E19 rat brain, choroid plexus and placenta, as well as P5 and adult brain and choroid plexus, expression of 13 main cannabidiol receptors was analysed. Results showed that cannabidiol rapidly entered both the developing and adult brains. Entry into CSF was more limited. Its transfer across the placenta was substantially restricted as only about 50% of maternal blood plasma cannabidiol concentration was detected in fetal plasma. Albumin was the main, but not exclusive, cannabidiol binding protein at all ages. Several transcripts for cannabidiol receptors were expressed in age- and tissue-specific manner indicating that cannabidiol may have different functional effects in the fetal compared to adult brain. [ABSTRACT FROM AUTHOR]

Background: Escalating rates of obesity and public health messages to reduce excessive sugar intake have fueled the consumption of artificial sweeteners (AS) in a wide range of products from breakfast cereals to beverages. However, several observational and laboratory studies link AS consumption with increased appetite, food intake, weight gain and glucose intolerance(1-5). There are very few probing their effect on adipocytes. Therefore, we want to study the effect of different AS on glucose uptake in adipocytes. Aims and objectives: To study the effect of saccharin, sucralose and cyclamate on glucose uptake in 3T3 cell lines. Materials and methods: 3T3 cells from ATCC were grown in DMEM. A day prior to the experiment, they were incubated with varying concentration (untreated, 1nM, 1µM or 1mM) of one of the AS for basal uptake and another set of wells were treated with AS and 10nM insulin for stimulated uptake. After 24h incubation, glucose uptake was studied with radiolabeled 2-deoxy glucose by liquid scintillation counter and expressed per mg of protein. Results and Conclusion: 2-way Anova was done. Cyclamate and saccharin showed an increase in uptake with increase in concentration. But sucralose shows a significant decrease in uptake with increase in concentration. All AS do not have similar effect on glucose uptake by cells. Sucralose decreases the glucose uptake by cells and may not be the AS of choice in people who already have decreased glucose uptake. AS are not metabolically inert, and it will be necessary to choose the right AS based on the metabolic status of the individual. [ABSTRACT FROM AUTHOR]

Presently several beta emitting radionuclides are in use as brachytherapy sources, due to their inherent advantages of short-range radiation dose delivery compared to their gamma emitting counterparts. 90Y is one of the well-known hard beta-emitting radioisotopes for the therapeutic application of radioactivity. Among various other modalities, 90Y resin microsphere as a brachytherapy source has its application for liver cancer. In the present study, 90Y was recovered from 235,238U,239Pu(nfast,f)90Sr(β−)90Y using Sr selective crown ether followed by quick purification using the Ion Chromatography technique. The purified 90Y was labelled in strong cation exchange resin to form 90Y resin microsphere. Various quality control parameters, e.g., water solubility, chemical, radionuclidic purity, and half-life, were verified using Gamma spectrometry, Cerenkov, and Liquid Scintillation Counting techniques. The obtained half-life was 64.05 h, which is in excellent agreement with the literature and is indirect evidence of the very high radionuclidic purity of the sample. A rapid method for the synthesis of 90Y resin microsphere brachytherapy source is being reported for the first time after its recovery from irradiated fast reactor fuel dissolver solution. After the separation of 90Sr along with trace level impurities inside the hot cell, simultaneous purification of parent 90Sr and daughter 90Y using single-stage Ion Chromatography step takes 15–25 min only in comparison to 24 h or more time using multistage conventional Ion exchange chromatography column, which saves the separation time and in turn, increase the yield of 90Y per separation campaign. [ABSTRACT FROM AUTHOR]

Liquid Scintillation Counting (LSC) gross alpha/beta screening is a valuable tool for providing rapid laboratory response for the analysis of human clinical urine samples during a large-scale radiation incident event. Verification of method performance, as required for clinical laboratory testing, is accomplished by the evaluation of routine, periodic measurements of radioactive spiked samples for quality control, performance testing, and accuracy checks. Radionuclide stability of alpha and beta emitters in urine for LSC analysis is an important consideration. The purpose of this work is to demonstrate optimal preparations and storage conditions of samples used for method verification. [ABSTRACT FROM AUTHOR]

A purification method is developed to determine 90Sr in radioactive waste. A separation based on Sr-resin® with a pretreatment using TRU-resin® provides satisfactory Sr recovery yields before the 90Sr measurement by liquid scintillation counting (LSC) regardless the analyzed samples with low or high activity level. The selectivity of the procedure is checked by measuring the 90Y ingrowth after different days of separation without waiting for secular equilibrium. In order to obtain a REACH compliant method without scintillation cocktails, a plastic scintillation resin selective for Sr is implemented on the basis of the developed protocol. The optimized method is applied successfully to representative nuclear waste including samples with high Pu content (effluents, concretes and sludges). [ABSTRACT FROM AUTHOR]

The handling and analysis of gaseous tritium is of interest for hydrogen isotope separation experiments. In this work, we present an easy-to-handle setup for catalytic oxidation to HTO, recovering all of the initially dosed gaseous tritium as determined by LSC, using CuO as a catalyst at a reaction temperature of 900 °C. Aiming to reduce cocktail waste, the LSC determination was downscaled to a microfluidic setup. The performance was evaluated based on the counting efficiency, which was shown to decrease significantly, as the sample volume was reduced to µl amounts, while no changes were observed over a wide range of sample-to-cocktail ratios. [ABSTRACT FROM AUTHOR]

During TRIGA reactor operation significant amounts of liquid radioactive waste are generated requiring appropriate management to ensure their safe disposal. Radiological characterization is an important activity needed to accomplish the waste acceptance criteria for different management steps including disposal. The purpose of this paper is to assess the activity concentrations of the ³1H. 383890Sr, 63286328Ni(difficult-to-measure), and gamma emitters (easy-to-measure) radionuclides in liquid radioactive waste generated by the TRIGA reactor operation and to establish a correlation among them to determine the scaling factors for this waste category. The radiological protocols applied for 6328Niand 3890Sr, separation and purification involve extraction chromatography using selective resins, while for H separation the distillation technique was applied. The assessment of gamma emitters was carried out using gamma-ray spectrometry and the detection of ³1H. 3890Sr, and 6328Niwas performed by liquid scintillation counting. The chemical yield of each experiment was determined by measuring the carrier added in each test by inductively coupled plasma optical emission spectrometry. The activity concentrations of 3890Sr, and 6328Niobtained were correlated with the activity concentration of 3860Co for establishing the scaling factor for the liquid radioactive waste stream. There were obtained good correlations but more experimental data are needed to determine the relevant scaling factors for these difficult-to- measure radionuclides. The scaling factors, once established, will improve and optimize the radiological characterization methodology applied for liquid radioactive waste as an easy and rapid method for assessment of concentration activities of difficult-to-measure radionuclides. Until now, no scaling factors data were reported for this liquid radioactive waste generated by TRIGA reactor operated by Institute for Nuclear Research Pitesti. The results obtained in this work represent preliminary data for establishing correlations between difficult-to-measure and easy-to-measure radionuclides and will be used for developing a scaling factor methodology. This will further be used to determine the inventory of difficult- to-measure radionuclides in different waste streams generated by TRIGA operation and decommissioning (foreseen after 2035). [ABSTRACT FROM AUTHOR]

This study was conducted to confirm the Cs-137 and Sr-90 adsorption properties of illite. In the experimental method, illite was added to Cs-137 and Sr-90 solutions and stirred. And Following the completion of the adsorption reaction, the solid/liquid phase was separated using a centrifuge, and the adsorption rate was calculated by measuring the radioactivity concentration of the separated liquid phase using a gamma nuclide analyzer, Liquid Scintillation Count (LSC). As a result of the experiment, after reacting for 30 min, 94% of Cs-137 was adsorbed. And 84.26% of Sr-90 was adsorbed. [ABSTRACT FROM AUTHOR]

Background and Objective: Lenacapavir (LEN) is a novel, first-in-class, multistage, selective inhibitor of human immunodeficiency virus type 1 (HIV-1) capsid function recently approved for the treatment of HIV-1 infection in heavily treatment-experienced adults with multidrug-resistant HIV-1 infection. The purpose of this multicohort study was to evaluate the pharmacokinetics, metabolism, excretion, safety, and tolerability of LEN following a single intravenous (IV) infusion of 10 mg LEN or 20 mg [14C]LEN in healthy participants. Methods: Twenty-one healthy adult participants were enrolled into the study and received either a single IV dose of 10 mg LEN (n = 8 active, n = 3 placebo; cohort 1) or a single IV dose of 20 mg [14C]LEN containing 200 µCi (n = 10; cohort 2). Blood, urine, and feces samples (when applicable) were collected after dosing, and radioactivity (cohort 2) was assessed using liquid scintillation counting in both plasma and excreta. LEN in plasma was quantified by liquid chromatography (LC) tandem mass spectroscopy (MS/MS) method bioanalysis. Metabolite profiling in plasma and excreta were performed using LC-fraction collect (FC)-high-resolution MS and LC-FC-accelerator mass spectrometry in plasma. Results: Between the 10 mg and 20 mg doses of LEN, the observed plasma exposure of LEN doubled, while the elimination half-life was similar. Following administration of 20 mg [14C]LEN (200 µCi), the mean cumulative recovery of [14C] radioactivity was 75.9% and 0.24% from feces and urine, respectively. The mean whole [14C] blood-to-plasma concentration ratio was 0.5–0.7, which showed a low distribution of LEN to red blood cells. Intact LEN was the predominant circulating species in plasma (representing 68.8% of circulating radioactivity), and no single metabolite contributed to > 10% of total radioactivity exposure through 1176 h postdose. Similarly, intact LEN was the most abundant component (32.9% of administered dose; 75.9% of recovered dose) measured in feces, with metabolites accounting for trace amounts. These results suggest metabolism of LEN is not a primary pathway of elimination. Of the metabolites observed in the feces, the three most abundant metabolites were direct phase 2 conjugates (glucuronide, hexose, and pentose conjugates), with additional metabolites formed to a lesser extent via other pathways. The administered LEN IV doses were generally safe and well-tolerated across participants in this study. Conclusions: The results of this mass balance study indicated that LEN was majorly eliminated as intact LEN via the feces. The renal pathway played a minor role in LEN elimination (0.24%). In addition, no major circulating metabolites in plasma or feces were found, indicating minimal metabolism of LEN. [ABSTRACT FROM AUTHOR]

To detect tritium levels in the human body, tritium in the urine must be measured. The investigation of the level of tritium activity in the urine of workers of the Iraqi Nuclear Research Center (INRC) has been realized in order to assess vocational exposure levels. Three worker groups in INRCs were chosen, involved in the Central Laboratories Directorate (CLD), the Decommissioning Directorate (DD), and the Radioactive Waste Treatment and Radioactive Waste Store Directorate (WTWSD), among others in Al- Tuwiatha site, in addition to the control group, as the research targets. Tritium concentration was determined in urine samples from 52 workers (aged 32-61) and 13 control people (aged 30-58). 65 urine samples of 50 mL were collected and analyzed. The Eichrom's Tritium Column way was used to handle the samples of urine, and the distillate tritium activity concentration was then assessed using Liquid Scintillation Counter. The effective and annual effective doses were estimated for the internal doses. The accuracy of urine sample measurements had been tested. The highest level of tritium activity samples of urine from three groups of workers in INRCs is 65.401 Bq/L, and for control group is 39.300 Bq/L, activity of tritium concentrations estimated by using counting scintillation of liquid (LSC) were found to be lower than Minimum Detectable Activity (MDA) of 1.95 Bq/L. The effective and annual effective dose from tritium was also assessed depend on results measured previously and standard values adapted by the International Commission on Radiological Protection. The effective highest doses for workers groups and control group were 497.048 ×10-3 and 298.680×10-3 nSv respectively. Highest annual effective dose 5757.773×10-³ and 5167.042×10-3 nSv respectively. These results were lowest than the allowed effective dose for the workers. [ABSTRACT FROM AUTHOR]

We present data from six years (January 2016–December 2021) of monitoring the isotope composition of precipitation at the Sv. Urban station in Eastern Slovenia. The 68 precipitation samples were collected as a monthly composite. The complete dataset (193 data pints) includes information on the stable isotope composition of hydrogen (δ2H) and oxygen (δ18O) and tritium activity concentration (A), obtained using isotope ratio mass spectrometry (IRMS) and liquid scintillation counting (LSC) following electrolytic enrichment (EE), respectively. The isotope data, together with meteorological data, are reported. Calculations of the deuterium excess (d-excess), monthly, seasonal, and annual unweighted and precipitation-weighted means and local meteoric water lines (LMWLs) were conducted. The mean values for δ2H, δ18O, d-excess, and A, weighted by precipitation, were −59.9‰, −8.81‰, 10.6‰, and 7.7 TU. The disparities between unweighted and precipitation-weighted δ2H, δ18O, d-excess, A, and LMWLs underscore the significance of non-uniformly distributed precipitation. Annual variations in slope and intercept of the LMWLs emphasize the importance of longer data records (48+ months) to capture consistent trends, while combining data over longer periods may distort accuracy due to distinct isotope differences between individual years related to the variability of climate conditions typical for Slovenia. [ABSTRACT FROM AUTHOR]

This article discusses tritium concentrations in monthly precipitation in part of the Difficult-to-Return Zone in Namie Town during 2012–2021. The tritium concentrations, which were measured with a low background liquid scintillation counter after carrying out an enrichment procedure, fluctuated seasonally from 0.10 ± 0.02 to 0.85 ± 0.02 Bq L−1. This range of concentrations is concluded to not be unusual based on comparisons with the concentrations at other sites and estimates of the past range of the concentrations. Moreover, no significant variations in observed tritium concentrations were observed due to decommissioning work at the Fukushima Dai-ichi Nuclear Power Plant. These results contribute to understanding the background level of tritium concentration in precipitation before the oceanic discharge of treated water from the Fukushima plant. In addition, this article evaluates the amount of tritium supplied to the ocean by terrestrial rainwater pouring into the Pacific Ocean via Ukedo River, which flows through Namie Town; this information will contribute to the discussion on the impact of the oceanic discharge of treated water. [ABSTRACT FROM AUTHOR]

Ciguatera, a global issue, lacks adequate capacity for ciguatoxin analysis in most affected countries. The Caribbean region, known for its endemic ciguatera and being home to a majority of the global small island developing states, particularly needs established methods for ciguatoxin detection in seafood and the environment. The radioligand receptor binding assay (r-RBA) is among the in vitro bioassays currently used for ciguatoxin analysis; however, similarly to the other chemical-based or bioassays that have been developed, it faces challenges due to limited standards and interlaboratory comparisons. This work presents a single laboratory validation of an r-RBA developed in a Cuban laboratory while characterizing the performance of the liquid scintillation counter instrument as a key external parameter. The results obtained show the assay is precise, accurate and robust, confirming its potential as a routine screening method for the detection and quantification of ciguatoxins. The new method will aid in identifying high-risk ciguatoxic fish in Cuba and the Caribbean region, supporting monitoring and scientific management of ciguatera and the development of early warning systems to enhance food safety and food security, and promote fair trade fisheries. [ABSTRACT FROM AUTHOR]

As a part of radiation emergency response, a rapid method for estimation of gross-α and gross-β activities in urine samples using liquid scintillation counting technique was standardized and validated using spiked urine samples. Effect of various storage conditions such as temperature, storage time and use of preservatives on estimation of gross-α and gross-β activities was investigated systematically. Measurement results revealed that urine samples either should be stored at lower temperatures (≤ 5 °C) or should be acidified with 1% v/v HCl for quantification of gross-α and gross-β activities with bias ≤ 10%. [ABSTRACT FROM AUTHOR]

This article presents two newly developed radiochemical procedures for the destructive analysis of niobium plates irradiated in the core of water-water energetic nuclear reactor (WWER), as well as determination of the specific activity of the generated during the irradiation metastable isotope 93mNb. The procedures were developed and tested using standard samples containing 93mNb and 94Nb. Measurements were made by low energy gamma spectrometry (LEGS) and liquid scintillation counting (LSC) and the obtained data were verified by interlaboratory comparison. All the results were compared with the calculated ones to confirm and evaluate the accuracy and superiority of the two measurement methods. [ABSTRACT FROM AUTHOR]

Background and Objective: Trofinetide is the first drug to be approved for the treatment of Rett syndrome, a neurodevelopmental disorder. The purpose of the study is to fully characterize the metabolic and excretion profiles of trofinetide in humans. Methods: This Phase 1, open-label, single-dose trial conducted in healthy male adults was designed to characterize the pharmacokinetics of trofinetide (absorption, metabolism, and excretion), mass balance of [14C]-trofinetide, and safety profile of trofinetide following administration of an oral 12-g dose administered as a mixture of trofinetide and [14C]-trofinetide. Blood, urine, and fecal samples were collected at prespecified timepoints. The pharmacokinetics of trofinetide were assessed in blood and urine samples using high-performance liquid chromatography (HPLC) with tandem mass spectrometric detection. Bioanalysis of radioactivity was conducted in blood, plasma, urine, and fecal samples using liquid scintillation counting. Metabolite profiling was conducted in blood, plasma, urine, and fecal samples using HPLC with liquid scintillation counting of chromatographic fractions. Safety and tolerability, including treatment-emergent adverse events (TEAEs), were assessed. Results: Blood concentration-time profiles of trofinetide and total radioactivity were almost superimposable up to ~12 h after dosing. Urine concentration-time profiles of trofinetide and total radioactivity were similar. Trofinetide was rapidly absorbed into the circulation with an initial rapid decline (half-life [t½] alpha ~2.6 h), followed by a relatively slow terminal elimination phase (t½ beta ~20 h). The blood-to-plasma total radioactivity ratios were 0.529–0.592, indicating a lack of affinity for the cellular portion of blood. Renal excretion accounted for 83.8% of the administered radiochemical dose; 15.1% was recovered in feces. Urine and fecal recovery of radioactivity accounted for 99% of the administered dose at 168 h after dosing. Parent [14C]-trofinetide was the major radiolabeled entity in blood and plasma (88.4% and 93.1% in area under the concentration–time curves from 0 to 12 h [AUC0–12] in pooled blood and plasma samples, respectively) and the major entity excreted in urine (91.5% in 0–48-h pooled urine samples) and in feces (52.7% in 0–192-h pooled fecal samples). Only small levels of metabolites were present. In blood and plasma, only two minor metabolites were identified (each metabolite ≤ 2.24% of the AUC0–12 pool). These two metabolites were also observed in urine and fecal samples (≤ 2.41% of dose). In feces, one additional metabolite (0.84% of dose) was identified. Two mild TEAEs were reported in two participants and were not considered related to trofinetide. There were no clinically meaningful changes in individual laboratory parameters, vital signs, physical findings, or electrocardiogram results. Conclusions: Metabolic and excretion profiles confirm that trofinetide undergoes minimal hepatic or intestinal metabolism and is primarily excreted unchanged in the urine. Trofinetide containing radiolabeled [14C]-trofinetide was well tolerated. Plain Language Summary: Trofinetide is the first approved treatment for Rett syndrome, a rare genetic condition that affects brain development. Study aims were to look at how a single oral dose of trofinetide is absorbed into the bloodstream, to see whether trofinetide's chemical structure is changed once in the body, and to see how trofinetide and any metabolites (chemically altered trofinetide) are removed from the body. Safety and tolerability of trofinetide were also assessed. Eight healthy adult men took a single oral 12-g dose administered as a mixture of 14C-radiolabeled and nonlabeled trofinetide. Researchers collected blood, urine, and stool samples at regular intervals for up to 10 days postdose to measure levels of trofinetide and its metabolites. Trofinetide was rapidly absorbed (time to maximum concentration was 2 h postdose) and was primarily present in the blood as the unaltered compound. Concentrations decreased rapidly during the first 24 h postdose and more slowly thereafter. Most of the dose was recovered in urine with a lower amount in stool samples (83.8% and 15.1% of the radiochemical dose, respectively). Total recovery in urine and stool samples was 99%, primarily as the chemically unaltered compound. Only low levels of three trofinetide metabolites were detected. Two metabolites were found in blood, urine, and stool samples, while one metabolite was found in stool samples only. Two mild treatment-emergent adverse events, considered to be unrelated to trofinetide, were reported. In summary, trofinetide is rapidly absorbed, minimally metabolized, and mainly removed from the body in the urine as the unchanged drug. [ABSTRACT FROM AUTHOR]

In this article the evaluation of the radon content in drinking water samples from the province of Reggio Calabria (Calabria, Southern Italy), is reported. In particular, the 222Rn activity concentration was measured by using the Liquid Scintillation Counting (LSC) PerkinElmer Tricarb 4910 TR setup, and it was compared with the parameter value (100 Bq L-1) reported in the Italian Legislative Decree 28/2016. The annual effective dose for the population of the investigated areas, due to the ingestion of 222Rn dissolved in water, was then evaluated only in those cases in which the parameter value was exceeded. Noteworthy, results reported in this paper represent a main reference for the investigated areas and constitute a baseline for future investigations regarding background radioactivity levels. [ABSTRACT FROM AUTHOR]

Radon (222Rn) is radium's immediate radioactive decay product (226Ra) in the uranium decay series. Radon is classified as a group 1 carcinogen due to its hazard to human health, and the evaluation of radon concentrations has become essential. Therefore, an advanced method was applied to a liquid scintillation counter (Hidex 300SL) to measure the radon concentration in groundwater. The estimated radon concentration was between 0.1 and 3.20 Bq/L, with an average of 0.96 Bq/L and with a standard deviation of 0.82 Bq/L. The estimated radon concentrations are in the safe range recommended by the United States Environmental Protection Agency (USEPA) and European Atomic Energy Community (EAEC). However, the values are far below the safe range set by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCARE), European Commission (EC), and World Health Organization (WHO) standards. Nevertheless, the estimated radon concentration by this advanced application ensured no risk of radon exposure from the groundwater of the tested area. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyse a capability of carbon-containing nanoparticles (CNPs) obtained by heating of organics, to influence mercury-induced neurotoxicity in biological system, such as presynaptic rat cortex nerve terminals. Methods. CNPs were obtained using method described in [6] by the combustion of citric acid and urea. The cortex nerve terminals isolated from Wistar rats were used in the experiments. [14C] glutamate uptake and release in the nerve terminals were monitored using a radiolabelled assay. In particular, rat brain nerve terminals (synaptosomes) were isolated from the rat cortex. The cortex regions were rapidly removed and homogenized in the ice-cold solution consisted of: sucrose 0.32 M; HEPES-NaOH 5 mM, pH 7.4; EDTA 0.2 mM. One synaptosomal preparation was isolated from one rat. The synaptosomes from brain homogenate were obtained according to the procedure proposed by Cotman with minor modifications [7] by differential centrifugation and Ficoll-400 density gradient centrifugation. The concentrations of proteins were monitored according to Larson. To measure the uptake of L-[14C] glutamate, the synaptosomal suspension was pre-incubated in the standard saline solution. Then, HgCl2 was applied to the synaptosomal incubation media, and synaptosomes were further incubated for 6 min before starting the uptake, which in turn was initiated by the application of the aliquots of non-radiolabelled L-glutamate (10 μM) supplemented with L-[14C] glutamate, 420 nM, 0.1 μCi/ml, and then the synaptosomes were incubated at 37 °C during 1 min to measure the initial rate of L-[14C] glutamate uptake. L-[14C] glutamate uptake was monitored with liquid scintillation counting using the ACS scintillation cocktail, 1.5 ml [8]. To measure the extracellular level of L-[14C] glutamate, the synaptosomes were were preincubated at 37 °C during 10 min to restore the ion gradients, and after that they were loaded with L-[14C] glutamate, 1 nmol per mg of protein, 238 mCi/mmol, in the standard saline solution at 37 °C during 10 min according to [9]. Total synaptosomal content of L-[14C] glutamate was equal to 200000±15000 cpm/mg protein. Results. In the first sets of the experiments, Hg2+ effects on the extracellular level of L-[14C] glutamate were assessed in nerve terminal preparations (Fig.1). It was shown a mercury-induced excitotoxic increase in the ambient level of L-[14C] glutamate in nerve terminal preparations. In the second sets of the experiments (Fig. 2), it was demonstrated that Hg2+ decreased the initial rate and accumulation of L-[14C] glutamate by nerve terminals starting from a concentration of 10 μM. Therefore, it was shown that a mercury-induced excitotoxic increase in the ambient level of L-[14C] glutamate in nerve terminal preparations (Fig. 1) resulted from weak functioning of glutamate transporter, and so significantly decreased L-[14C] glutamate uptake (Fig. 2). In the third sets of the experiments, it was shown that CNPs from heating of citric acid/urea mitigated an excitotoxic mercury-induced increase in the extracellular level of L-[14C] glutamate in nerve terminal preparations. The latter was equal to 0.425 ± 0.023 nmol/mg of proteins after combined application of HgCl2 (5 μM) and CNPs (1 mg/ml) (Р ≤ 0.05 as compared to effect of Hg2+per se; n = 6) and 0.460 ± 0.017 nmol/mg of proteins after combined application of HgCl2 (5 μM) and CNPs (10 mg/ml) (Р ≤ 0.05 as compared to effect of Hg2+ per se; n = 6). Therefore, CNPs were able to mitigate in an acute manner excitotoxic Hg2+-induced increase in the extracellular L-[14C]glutamate level in nerve terminals by 37%, thereby being a provisional Hg2+ scavenger. Conclusions. CNPs can mitigate Hg2+-induced excitotoxicity in nerve terminals. Taking into account this fact, it can be assumed that these nanoparticles can be used as Hg2+ adsorbent in the human organism. Besides biotechnological implementation of data, developed approach can be applicable for monitoring capability of different particles and compounds to mitigate Hg2+-mediated threat. [ABSTRACT FROM AUTHOR]

The hydrogen radioactive isotope, tritium, not only reflects seasonal variation in precipitation but also variations on a local level. To use this radioisotope in authentication and geographical indication procedures, the tritium levels in vines, grapes, and wine were measured in two forms: (1) tissue-free water tritium (TFWT), measured in the free water of the plant or the aqueous phase of the wine; (2) organically bound tritium (OBT), measured in the organic part of the plant or wine (as ethanol). This paper presents the tritium behavior in vines from May to October and in the wine produced from harvested grapes for both tritium forms (TFWT and OBT) in connection with environmental tritium concentrations in air and precipitations during the 2019–2023 vegetation periods near the Râmnicu Vâlcea city. If the tritium of tissue-free water was influenced by precipitation and air humidity during the harvest period, the organically bound tritium recorded a maximum level with a delay of 1–2 months compared with tritium’s seasonal variation in precipitation and air. The tritium values of early mean in precipitation and ethanol from wine were approximately an average value of 11 TU for all 5 years of observations.

Cancer, a leading cause of death in Canada, is typically treated with conventional methods like chemotherapy, surgery, and radiotherapy. An innovative cancer therapy, Diffusing alpha-emitter Radiation Therapy (Alpha DaRT), using radioactive sources with 224Ra atoms, has recently been introduced to enhance cancer treatment efficiency through heightened radiobiological properties. The purpose of this work was to characterize an Alpha DaRT source from its alpha and beta energy spectra measured with a modern liquid scintillation counter. An Alpha-DaRT source was provided by Alpha Tau Medical Ltd., and measured using a Hidex 600SL liquid scintillation counter (LSC). Counts from alpha and beta particles were separated by the counter and binned according to their emitted energies. An in-house Python program was developed to extract the activities of each daughter in the 224Ra decay chain. A discernible disparity persists between theoretically calculated 212Po activity (224Ra daughter) and experimentally measured activities by Hidex 600SL. Traces of 228Th contamination are quantified to be less than 0.002% of the 224Ra activity. Due to the fast (0.3 μs half-life) decay of 212Po, part of the alpha activity is missed by the counter. This phenomenon should be considered in evaluating liquid scintillation efficiencies for quantitative spectral measurements. [ABSTRACT FROM AUTHOR]

Liquid scintillation counting is widely used in the rapid measurement of beta activity in environmental and biological samples. However, the single-photons generated by chemiluminescence and photoluminescence in liquid scintillation cocktails seriously affect the measurement accuracy of low-energy beta activity. A novel method based on the combination of the signal characteristic analysis and selective gate to eliminate the single-photon signal was developed. A preprocessing circuit made of a fast response time photomultiplier tube (PMT, Hamamatsu R9420), two charge-sensitive preamplifiers (CSP), two comparators, an analog switch and delay-line devices were designed and developed to verify the feasibility and effectiveness. The output signals from the last dynode were characterized in the pulse time and were used to discriminate the beta signals from the single-photon ones. The beta signals were "tagged" through pulse width detection, pulse width-amplitude transform and pulse-height discrimination with the first comparator, the first CSP and the second comparator. The "tagged" beta signal were applied to control the analog switch. The anode signals were specially delayed and then selected by the analog switch to achieve the single-photon signal elimination. Liquid scintillation cocktails containing 14 C or NaOH used as beta or single-photon sources were provided to verify the feasibility of the principle. The results showed that the typical fall time of the single-photon and beta signal was 16.05 ns and 43.17 ns. The single-photon rejection ratio is 2.76 × 10 − 3 ± 3.89 × 10 − 5 , and the detection efficiency is up to 93. 02 % ± 0. 59 %. • A single-photon elimination method was validated with PSD and delayed coincidence. • The detection efficiency and rejection ratio of the method are 93. 02 % ± 0. 59 % and 2.76 × 10 − 3 ± 3.89 × 10 − 5. [ABSTRACT FROM AUTHOR]

Currently, rapid, and efficient methods are pivotal in environmental monitoring within nuclear nations and in the effective management of radiation emergencies. For this reason, a comprehensive comparative analysis was conducted to select a sensitive, rapid, and robust method for determining the natural isotopes of 210Pb, 210Bi, and 210Po in water samples using a single analytical technique. The method is demonstrated using an ultra-low background liquid scintillation spectrometer Wallac 1220 Quantulus. In total, 9 laboratory procedures based on TOPO, TIOA, HDEHP, and scintillation cocktails were compared to determine the optimal method for mutual analysis of three isotopes within the same sequence action. The evaluation was carried out using samples spiked with a prepared SRM 4337 210Pb solution, and it included an assessment of several validation criteria. The recoveries (%) of 210Pb, 210Bi, and 210Po were 57.1%, 99.1% and 78.6% respectively, with the solvent extractor based on 0.20 M TIOA in toluene and using UG AB scintillation cocktail. The minimum detectable activities (MDA) of 210Pb, 210Bi, and 210Po were found to be 17.8, 6.80, and 0.90 [mBq/L] for the measurements using LSC, respectively. However, the least effective was the extraction with HDEHP in toluene/UG XR. The developed procedure is applicable in most laboratory conditions and could be applied to any aqueous samples. This approach gives a new opportunity with fast screening of environmental samples for a radiation risk assessment. • A method of efficient 210Pb, 210Bi, and 210Po simultaneous extraction was developed. • Performance evaluation of various extraction techniques was carried out. • Solvent extractor with 0.20 M TIOA in toluene yields the highest recovery. • The proposed method quickly screens environmental samples, assessing radiation risk. [ABSTRACT FROM AUTHOR]

and polyfluoroalkyl substances have gained increased attention due to their persistence, ubiquitous presence in the environment, and toxicity. We hypothesised that the formation of non-extractable residues [NER] occurs in soils and contributes to the overall persistence of these priority pollutants, and that NER formation is controlled by temperature. To test these hypotheses, we used 14C-labelled perfluorooctanoic acid [PFOA] as target compound, added it to two arable soils (Cambisol, Luvisol), and incubated them at 10 °C and 20 °C in the dark. To support potential co-metabolic decomposition, some samples were additionally fed with glucose to enhance microbial activity. The PFOA residues were then sequentially extracted using 0.01 M CaCl 2 , followed by accelerated solvent extraction (ASE) with methanol or methanol/acetic acid after 0, 1, 3, 9, 30, 62, and 90 days of incubation. In addition, we monitored the release of 14C into the gas phase as well as [14C]-PFOA-NER after dry combustion and liquid scintillation counting. After 90 days, we found that the [14C]-PFOA content declined in the extraction order of CaCl 2 ((bio)available fraction) > ASE (residual fraction) > NER > gas fraction), with most rapid changes occurring in the first 9 days of incubation. NER formation was different in the two soils and reached 5–9% of the applied amount in the Cambisol and Luvisol, respectively. Noteworthy the proportion of 14C-PFOA in the (bio)available fraction remained relatively stable over time at 56–62% of the applied amount, indicating the reversible transfer into this fraction from a bi-exponentially declining residual (ASE) pool. These dissipation patterns were neither influenced by temperature nor by the addition of glucose. We conclude that NER exist for PFOA, but that the majority of PFOA remains in (bio)available form, thus maintaining toxicity and mobility in soil for prolonged periods of time. [Display omitted] • Incubation with 14C-labelled PFOA confirms slow dissipation rates. • Non-extractable residues form between just 5% and 9% of PFOA. • The majority of PFOA remains in CaCl 2 -extractable, bioavailable form. • Temperature rise did not affect sequestration and dissipation rates. [ABSTRACT FROM AUTHOR]