Radiotracer Research Articles

Turning brain MRI into diagnostic PET: 15O-water PET CBF synthesis from multi-contrast MRI via attention-based encoder–decoder networks

Accurate quantification of cerebral blood flow (CBF) is essential for the diagnosis and assessment of a wide range of neurological diseases. Positron emission tomography (PET) with radiolabeled water (15O-water) is the gold-standard for the measurement of CBF in humans, however, it is not widely available due to its prohibitive costs and the use of short-lived radiopharmaceutical tracers that require onsite cyclotron production. Magnetic resonance imaging (MRI), in contrast, is more accessible and does not involve ionizing radiation. This study presents a convolutional encoder–decoder network with attention mechanisms to predict the gold-standard 15O-water PET CBF from multi-contrast MRI scans, thus eliminating the need for radioactive tracers. The model was trained and validated using 5-fold cross-validation in a group of 126 subjects consisting of healthy controls and cerebrovascular disease patients, all of whom underwent simultaneous 15O-water PET/MRI. The results demonstrate that the model can successfully synthesize high-quality PET CBF measurements (with an average SSIM of 0.924 and PSNR of 38.8 dB) and is more accurate compared to concurrent and previous PET synthesis methods. We also demonstrate the clinical significance of the proposed algorithm by evaluating the agreement for identifying the vascular territories with impaired CBF. Such methods may enable more widespread and accurate CBF evaluation in larger cohorts who cannot undergo PET imaging due to radiation concerns, lack of access, or logistic challenges.

2D Path of a Radioactive Tracer within a Lamellar Settler: Experiments and Modeling

2D Path of a Radioactive Tracer within a Lamellar Settler: Experiments and Modeling

Increasing winter wheat yield and nitrogen utilization, and reducing residual soil nitrogen in semi-humid areas: A study matching deep fertilizer application with regional water scenarios

The deep fertilizer application (DF) has been recommended as an effective strategy for promoting crop growth and yield formation. However, the controversial discussion revolves on the challenge of effectively using DF to simultaneously increase crop nitrogen (N) uptake and minimize residual nitrate contents to enhance N utilization efficiency. Based on a precipitation manipulation experiment conducted during 2019–2022 in a semi-humid area, we examined how annual precipitation amount during wheat growing season (125 mm = dry year; 200 mm = normal year; 275 mm = wet year) and the soil water storage before sowing (500 mm, SWSS500; 400 mm, SWSS400; 300 mm, SWSS300) variability affected the N uptake, N utilization efficiency, yield, and residual soil nitrate content in wheat fields treated with N fertilization at different depths (conventional surface fertilization depth of 5 cm: D5; 15 cm: D15; 25 cm: D25; 35 cm: D35). A complementary field experiment was also performed under natural rainfall condition using the 15N tracer technique to quantify the fate of fertilizer-N and 15N use efficiency (15NUE). 15N analyses showed that DF (D15, D25 and D35) significantly increased 15NUE by improving wheat 15N uptake (5.8–15.3%) and reducing potential 15N loss (9.6–12.3%) compared with D5, but the residual soil 15N in the 0–1.0 m layer increased (13.2–26.3%) as the fertilization depth increased (p < 0.05). The simulated precipitation experiment showed that compared with D5, DF significantly increased wheat N uptake, N utilization efficiency and yield by 1.4–16.4%, 1.4–14.0% and 3.3–21.5%, respectively, in the dry and normal years. In the wet year, N uptake, N utilization efficiency and yield under D15 increased by 1.9–9.8%, 2.1–11.1% and 2.2–13.4% compared to other fertilization depth treatments (p < 0.05). SWSS500 and SWSS400 significantly increased the N uptake (9.8–65.0%) and yield (0.6–69.3%) under all fertilization depth treatments irrespective of the annual precipitation amount than SWSS300 (p < 0.05). DF increased the residual NO3–-N concentration (0–2.0 m soil layer) by 2.2–7.3% compared to D5 across all annual precipitation amounts and SWSS levels, and D35 increased the maximum downward movement of NO3–-N to 1.4 m under wet year within SWSS500. DF at the depth of 14–20 cm effectively improved wheat N uptake and yield as well as minimizing the residual soil NO3–-N content. Applying moderate DF can enhance sustainable wheat production with high efficiency and yields in semi-humid regions.

Mutations in DNAJC19 cause altered mitochondrial structure and increased mitochondrial respiration in human iPSC-derived cardiomyocytes

BackgroundDilated cardiomyopathy with ataxia (DCMA) is an autosomal recessive disorder arising from truncating mutations in DNAJC19, which encodes an inner mitochondrial membrane protein. Clinical features include an early onset, often life-threatening, cardiomyopathy associated with other metabolic features. Here, we aim to understand the metabolic and pathophysiological mechanisms of mutant DNAJC19 for the development of cardiomyopathy. MethodsWe generated induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) of two affected siblings with DCMA and a gene-edited truncation variant (tv) of DNAJC19 which all lack the conserved DnaJ interaction domain. The mutant iPSC-CMs and their respective control cells were subjected to various analyses, including assessments of morphology, metabolic function, and physiological consequences such as Ca2+ kinetics, contractility, and arrhythmic potential. Validation of respiration analysis was done in a gene-edited HeLa cell line (DNAJC19tvHeLa). ResultsStructural analyses revealed mitochondrial fragmentation and abnormal cristae formation associated with an overall reduced mitochondrial protein expression in mutant iPSC-CMs. Morphological alterations were associated with higher oxygen consumption rates (OCRs) in all three mutant iPSC-CMs, indicating higher electron transport chain activity to meet cellular ATP demands. Additionally, increased extracellular acidification rates suggested an increase in overall metabolic flux, while radioactive tracer uptake studies revealed decreased fatty acid uptake and utilization of glucose. Mutant iPSC-CMs also showed increased reactive oxygen species (ROS) and an elevated mitochondrial membrane potential. Increased mitochondrial respiration with pyruvate and malate as substrates was observed in mutant DNAJC19tv HeLa cells in addition to an upregulation of respiratory chain complexes, while cellular ATP-levels remain the same. Moreover, mitochondrial alterations were associated with increased beating frequencies, elevated diastolic Ca2+ concentrations, reduced sarcomere shortening and an increased beat-to-beat rate variability in mutant cell lines in response to β-adrenergic stimulation. ConclusionsLoss of the DnaJ domain disturbs cardiac mitochondrial structure with abnormal cristae formation and leads to mitochondrial dysfunction, suggesting that DNAJC19 plays an essential role in mitochondrial morphogenesis and biogenesis. Moreover, increased mitochondrial respiration, altered substrate utilization, increased ROS production and abnormal Ca2+ kinetics provide insights into the pathogenesis of DCMA-related cardiomyopathy.

High Temperature Oxidation of Zircaloy-4 Under Conditions Simulating a Loss of Cooling Accident in Spent Fuel Pools Examined with Raman Imaging and 18o Tracer Techniques

Since the Fukushima accident, an increased attention is continuously paid to the vulnerability of the Spent Fuel Pools (SFPs). In SFPs, for different reasons, degradation of the fuel rods induced by oxidation in air-steam mixtures after dewatering is a major safety concern: (i) the cladding material is the only barrier left against fission product dissemination, (ii) the heat released by the oxidation reactions can overcome the residual decay heat of the fuel and may become the main driving force to the accident escalation, (iii) hydrogen production is a strong concern because of the presence of steam, (iv) presence of air in the atmosphere is known to be an aggravating factor because of the “catalytic” role of nitrogen on the oxidation mechanism.In this study, high temperature oxidation tests in oxygen, air and air - steam atmospheres were performed with Zircaloy-4 cladding tubes and plates specimens. Because spent fuels are concerned, the presence of the corrosion oxide scale formed in reactor during in-service operation was also considered. The tests described in this study were restricted to the 700 – 950°C range, and mostly performed at 850°C. Raman imaging was used to examine the specimens after the oxidation tests, either directly at the oxide surface, or on metallographic preparations for cross-section examinations.We first used new opportunities given by Raman imaging to analyze, at least qualitatively, the structural and mechanical phenomena involved in this particular corrosion phenomena. Indeed, this method can provide information on the nature of phases that are present in the scale and on the stress level with sub-micron spatial resolution. The different methods used to extract this information that is present in the Raman data will be described and discussed.Moreover, isotopic substitution was also considered. Actually, Raman spectroscopy has also the ability to quantitatively extract the 18O distribution in a zirconia oxide scale after a two stage experiment with a fair accuracy. Raman imaging gave clear evidence for different characteristic distributions of 18O in the scales. Some of them have been correlated with the development of cracks and porosity in the oxide which allows the corroding medium to penetrate locally in the scales. Nitrogen appears to have no or limited influence on the oxygen diffusion, but is observed to reach the metal/oxide interface much faster than oxygen. Thus, we also emphasize the potential of this method to investigate the 18O distribution in such complex corrosion scales.

Differential response of Hg-methylating and MeHg-demethylating microbiomes to dissolved organic matter components in eutrophic lake water

Methylmercury (MeHg) production in aquatic ecosystems is a global concern because of its neurotoxic effect. Dissolved organic matter (DOM) plays a crucial role in biogeochemical cycling of Hg. However, owing to its complex composition, the effects of DOM on net MeHg production have not been fully understood. Here, the Hg isotope tracer technique combined with different DOM treatments was employed to explore the influences of DOM with divergent compositions on Hg methylation/demethylation and its microbial mechanisms in eutrophic lake waters. Our results showed that algae-derived DOM treatments enhanced MeHg concentrations by 1.42−1.53 times compared with terrestrial-derived DOM. Algae-derived DOM had largely increased the methylation rate constants by approximately 1−2 orders of magnitude compared to terrestrial-derived DOM, but its effects on demethylation rate constants were less pronounced, resulting in the enhancement of net MeHg formation. The abundance of hgcA and merB genes suggested that Hg-methylating and MeHg-demethylating microbiomes responded differently to DOM treatments. Specific DOM components (e.g., aromatic proteins and soluble microbial byproducts) were positively correlated with both methylation rate constants and the abundance of Hg-methylating microbiomes. Our results highlight that the DOM composition influences the Hg methylation and MeHg demethylation differently and should be incorporated into future Hg risk assessments in aquatic ecosystems.

Gamma-ray spectra of post-irradiated uranium salt for total mass accounting with sodium-22 tracer

In order to meet the safeguard requirements for Nuclear Material Control and Accountability (MC&A) in liquid-fueled molten salt reactors, fuel salt transportation, and fuel cycle processes, it is important to develop effective methods for measuring and monitoring the mass of molten fuel salt or coolant salt. This paper seeks to validate the radioactive tracer dilution (RTD) method used for determining the mass of irradiated uranium-bearing molten salt. Small scale testing was conducted for this method by irradiating 6.065 g of MgCl–KCl–UCl3 salt mixture with 1.21 mg of 235U at The Ohio State University, resulting in a neutron fluence of 4.0 × 1016 n/cm2. Gamma spectra were acquired over the course of a 42-day period starting in March 2023 to assess fission products and activity levels of the 22Na tracer that was added before irradiation. No additional interference peaks were observed to overlap with the 1274.54 keV energy peak from 22Na, aside from the known 154Eu peaks, which can be corrected based on prior studies. By placing a thin piece of lead between the source and detector, deadtime was effectively reduced while still allowing observation of the higher-energy peaks, most notably around the 154Eu peak at 1004.76 keV used for interference correction. Overall, the uranium salt irradiation techniques applied in this experiment demonstrate the potential of the RTD method to effectively measure small irradiated samples for large scale molten fuel salt applications.

Deuterium MR spectroscopy: potential applications in oncology research.

Metabolic imaging in clinical practice has long relied on PET with fluorodeoxyglucose (FDG), a radioactive tracer. However, this conventional method presents inherent limitations such as exposure to ionizing radiation and potential diagnostic uncertainties, particularly in organs with heightened glucose uptake like the brain. This review underscores the transformative potential of traditional deuterium MR spectroscopy (MRS) when integrated with gradient techniques, culminating in an advanced metabolic imaging modality known as deuterium MRI (DMRI). While recent advancements in hyperpolarized MRS hold promise for metabolic analysis, their widespread clinical usage is hindered by cost constraints and the availability of hyperpolarizer devices or facilities. DMRI, also denoted as deuterium metabolic imaging (DMI), represents a pioneering, single-shot, and noninvasive paradigm that fuses conventional MRS with nonradioactive deuterium-labelled substrates. Extensively tested in animal models and patient cohorts, particularly in cases of brain tumours, DMI's standout feature lies in its seamless integration into standard clinical MRI scanners, necessitating only minor adjustments such as radiofrequency coil tuning to the deuterium frequency. DMRI emerges as a versatile tool for quantifying crucial metabolites in clinical oncology, including glucose, lactate, glutamate, glutamine, and characterizing IDH mutations. Its potential applications in this domain are broad, spanning diagnostic profiling, treatment response monitoring, and the identification of novel therapeutic targets across diverse cancer subtypes.

Enhancement of intestinal calcium transport by short-chain fatty acids: roles of Na+/H+ exchanger 3 and transient receptor potential vanilloid subfamily 6.

Small organic molecules in the intestinal lumen, particularly short-chain fatty acids (SCFAs) and glucose, have long been postulated to enhance calcium absorption. Here, we used 45Ca radioactive tracer to determine calcium fluxes across the rat intestine after exposure to glucose and SCFAs. Confirming previous reports, glucose was found to increase the apical-to-basolateral calcium flux in the cecum. Under apical glucose-free conditions, SCFAs (e.g., butyrate) stimulated the cecal calcium fluxes by approximately twofold, while having no effect on proximal colon. Since SCFAs could be absorbed into the circulation, we further determined whether basolateral SCFA exposure rendered some positive actions. It was found that exposure of duodenum and cecum on the basolateral side to acetate or butyrate increased calcium fluxes. Under butyrate-rich conditions, cecal calcium transport was partially diminished by Na+/H+ exchanger 3 (NHE3) inhibitor (tenapanor) and nonselective transient receptor potential vanilloid subfamily 6 (TRPV6) inhibitor (miconazole). To confirm the contribution of TRPV6 to SCFA-stimulated calcium transport, we synthesized another TRPV6 inhibitor that was demonstrated by in silico molecular docking and molecular dynamics to occlude TRPV6 pore and diminish the glucose- and butyrate-induced calcium fluxes. Therefore, besides corroborating the importance of luminal molecules in calcium absorption, our findings provided foundation for development of more effective calcium-rich nutraceuticals in combination with various absorptive enhancers, e.g., glucose and SCFAs.NEW & NOTEWORTHY Organic molecules in the intestinal lumen, e.g., glucose and short-chain fatty acids (SCFAs), the latter of which are normally produced by microfloral fermentation, can stimulate calcium absorption dependent on transient receptor potential vanilloid subfamily 6 (TRPV6) and Na+/H+ exchanger 3 (NHE3). A selective TRPV6 inhibitor synthesized and demonstrated by in silico docking and molecular dynamics to specifically bind to the pore domain of TRPV6 was used to confirm a significant contribution of this channel. Our findings corroborate physiological significance of nutrients and SCFAs in enhancing calcium absorption.

Accessible sampling methodologies to quantify the net methane emission from landfill cells

Landfills are one of the main sources of anthropogenic methane (CH4) emissions in urban areas. The environmental conditions specific to each locality, the waste management and the infrastructure of each landfill will influence the emissions of this gas. By applying different methodologies, this study aims to investigate the total contribution of CH4 to the atmosphere from a landfill, as well as the surface fluxes within the cells and the passive gas vents. According to the results, mean atmospheric CH4 concentrations from landfills were measured up to 6 ppm higher than those recorded in urban areas and locations distant from CH4 fixed sources. Two closed cells were selected to study surface fluxes by static chamber technique. CH4 uptake (1.65E-08 to 2.04E-06 g m−2 d−1) was recorded in between 60% and 87.5% of the chambers, indicating that the surface acted as a sink for the gas, as compared to the mean uptake observed from a control site (1.72E-06 g m-2 d−1). CH4 emissions from gas vents were studied using a tracer technique with permeable capsules, a methodology used for the first time in a landfill. Relatively high emissions were detected, up to 1.20E+04 g d−1. Finally, from the net CH4 emission calculated, the energy produced if the emitted CH4 were captured was estimated to be 3.23 GJ. The results highlight the importance of these studies for decision-makers to plan future landfill infrastructure adequately, implement mitigation measures to reduce emissions of this potent greenhouse gas and contribute to the energy system resources.

Magnetic Particle Imaging: From Tracer Design to Biomedical Applications in Vasculature Abnormality.

Magnetic particle imaging (MPI) is an emerging non-invasive tomographic technique based on the response of magnetic nanoparticles (MNPs) to oscillating drive fields at the center of a static magnetic gradient. In contrast to magnetic resonance imaging (MRI), which is driven by uniform magnetic fields and projects the anatomic information of the subjects, MPI directly tracks and quantifies MNPs in vivo without background signals. Moreover, it does not require radioactive tracers and has no limitations on imaging depth. This article first introduces the basic principles of MPI and important features of MNPs for imaging sensitivity, spatial resolution, and targeted biodistribution. The latest research aiming to optimize the performance ofMPI tracers is reviewed based on their material composition, physical properties, and surface modifications. While the unique advantages of MPI have led to a series of promising biomedical applications, recent development of MPI in investigatingvascular abnormalities in cardiovascular and cerebrovascular systems, and cancer are also discussed. Finally, recent progress and challenges in the clinical translation of MPI are discussed to provide possible directions for future research and development.

Axillary surgery in oncologic breast surgery: a narrative review.

With the improved survival for breast cancer there is now an increased focus on quality of life after treatment. Axillary surgery is known to be associated with significant risk of arm morbidity feared by the patients, and several studies have shown de-escalation is possible in different settings. In this review, an overview will be given on new techniques and procedures for de-escalation of axillary surgery in breast cancer patients and the subsequent implications for adjuvant systemic treatment. This study is a narrative review. PubMed was searched for relevant publications in English published between January 2018-June 2023. Only publications with major impact on clinical practice have been included with main emphasis on meta-analysis. In addition, Clinicaltrial.gov has been searched for on-going studies. New tracer techniques are described as well as the on-going reduction in axillary lymph node dissection (ALND) at primary surgery even in node positive patients, and the axillary staging possibilities after down-staging of the axilla by neoadjuvant treatment. Finally axillary staging at local recurrence and in case of ductal carcinoma in situ is described. ALND is no longer routinely recommended in many node positive patients and further de-escalation is investigated. The lack of knowledge on precise axillary status will require cooperating studies between oncologists and breast surgeons in order to avoid escalation of systemic treatment due to the lack of applicability of trial eligibility criteria. Furthermore, investigations on the use of axillary imaging for staging are needed.

Celebrating a pioneer in geochemical tracer science for groundwater and surface water research: Professor Ian Cartwright

Over a more than 35-year career Professor Ian Cartwright's research has provided advances in the understanding of a wide range of earth-science processes, from metamorphic geology to palaeo-climates, groundwater hydrology, catchment hydrology and geochemistry. His research has predominantly utilised geochemistry, stable and radioactive isotope tracers to understand links between palaeo-climate and groundwater, geochemical processes impacting on groundwater and surface water quality, and metamorphic processes. He has made outstanding contributions to scientific knowledge and training through mentoring numerous PhD and masters students, journal editorial roles – including as a long-time Associate Editor for Applied Geochemistry, and active participation in conferences, professional societies and working groups – such as the Applied Isotope Geochemistry group and the International Association of Geochemistry. As he moves into retirement, we take the opportunity to summarise his impact and contributions across many scientific disciplines and reflect on the significance of his distinguished career.

Hyperpolarized 129Xe MRI, 99mTc scintigraphy, and SPECT in lung ventilation imaging: a quantitative comparison

The current clinical standard for functional imaging of patients with lung ailments is nuclear medicine scintigraphy and Single Photon Emission Computed Tomography (SPECT) which detect the gamma decay of inhaled radioactive tracers. Hyperpolarized (HP) Xenon-129 MRI (XeMRI) of the lungs has recently been FDA approved and provides similar functional images of the lungs with higher spatial resolution than scintigraphy and SPECT. Here we compare Technetium-99m (99mTc) diethylene-triamine-pentaacetatescintigraphy and SPECTwith HP XeMRI in healthy controls, asthma, and chronic obstructive pulmonary disorder (COPD) patients. 59 subjects, healthy, with asthma, and with COPD, underwent 99mTc scintigraphy/SPECT, standard spirometry, and HP XeMRI. XeMRI and SPECT images were registered for direct voxel-wise signal comparisons. Images were also compared using ventilation defect percentage (VDP), and a standard 6-compartment method. VDP calculated from XeMRI and SPECT images was compared to spirometry. Median Pearson correlation coefficient for voxel-wise signal comparison was 0.698 (0.613-0.782) between scintigraphy and XeMRI and 0.398 (0.286-0.502) between SPECT and XeMRI. Correlation between VDP measures was r=0.853, p<0.05. VDP separated asthma and COPD from the control group and was significantly correlated with FEV1, FEV1/FVC, and FEF 25-75. HP XeMRI provides equivalent information to 99mTc SPECT and standard spirometry measures. Additionally, XeMRI is non-invasive, hence it could be used for longitudinal studies for evaluating emerging treatment for lung ailments.

CycloSiFA: The Next Generation of Silicon-Based Fluoride Acceptors for Positron Emission Tomography (PET).

The ring-opening Si-fluorination of a variety of azasilole derivatives cyclo-1-(iPr2 Si)-4-X-C6 H3 -2-CH2 NR (4: R=2,6-iPr2 C6 H3 , X=H; 4 a: R=2,4,6-Me3 C6 H2 , X=H; 9: R=2,6-iPr2 C6 H3 , X=tBuMe2 SiO; 10: R=2,6-iPr2 C6 H3 , X=OH; 13: R=2,6-iPr2 C6 H3 , X=HCCCH2 O; 22: R=2,6-iPr2 C6 H3 , X=tBuMe2 SiCH2 O) with different 19 F-fluoride sources was studied, optimized and the experience gained was used in a translational approach to create a straightforward 18 F-labelling protocol for the azasilole derivatives [18 F]6 and [18 F]14. The latter constitutes a potential clickable CycloSiFA prosthetic group which might be used in PET tracer development using Cu-catalysed triazole formation. Based on our findings, CycloSiFA has the potential to become a new entry into non-canonical labelling methodologies for radioactive PET tracer development.

CycloSiFA: Die nächste Generation von Silicium‐basierten Fluoridakzeptoren für die Positronenemissionstomographie (PET)

AbstractDie ringöffnende Si‐Fluorierung einer Vielzahl von Azasilolderivaten Cyclo‐1‐(iPr2Si)−4‐X−C6H3−2‐CH2NR (4: R=2,6‐iPr2C6H3, X=H; 4 a: R=2,4,6‐Me3C6H2, X=H; 9: R=2,6‐iPr2C6H3, X=tBuMe2SiO; 10: R=2,6‐iPr2C6H3, X=OH; 13: R=2,6‐iPr2C6H3, X=HCCCH2O; 22: R=2,6‐iPr2C6H3, X=tBuMe2SiCH2O) mit verschiedenen 19F‐Fluoridquellen untersucht, optimiert und die gewonnenen Erfahrungen in einem translationalen Ansatz genutzt, um ein einfaches 18F‐Markierungsprotokoll für die Azasilolderivate [18F]6 und [18F]14 zu erstellen. Letzteres stellt eine potenziell klickbare CycloSiFA‐prothetische Gruppe dar, die bei der Entwicklung von PET‐Tracern unter Verwendung der Cu‐katalysierten Triazolbildung eingesetzt werden könnte. Auf der Grundlage unserer Ergebnisse hat CycloSiFA das Potenzial, ein neuer Einstieg in nicht‐kanonische Markierungsmethoden für die Entwicklung radioaktiver PET‐Tracer zu werden.

Molten salt-assisted carbonized zeolite imidazolate framework on nickel foam for highly efficient iodide capture in fluoride molten salts

Removing radioactive iodide ions from molten salt nuclear fuel in fourth-generation molten salt reactors is essential for nuclear and environmental safety. In the present work, a synthesis strategy as synthesised in molten salt was utilized by employing. A two-dimensional nanoscale carbon membrane with a hierarchical pore structure (HNPC@NF) was successfully prepared via molten salt-assisted carbonized three-dimensional ZIF-8 grown in situ on nickel foam, which showed the maximum adsorption capacity of 55.6 mg/g for iodide ions in LiF-BeF2 molten salt within 8 h under static adsorption experiments. HNPC@NF was capable of effectively adsorbing iodide ions even in the presence of various cations and anions such as Cs+, Sr2+, Nd3+, Sm3+and Br- and also adsorbed coexisting ions. The different-sized pores of HNPC@NF act as filters, sieving, and occluding for these ions. Radioactive tracer experiments have confirmed that HNPC@NF could adsorb 131I in simulated spent nuclear fuel salt and captured radionuclides 99mTc, 99Mo, 239Np, and 132Te within 4 h without interacting with 237U. The adsorption mechanism was determined by combining kinetic fitting, XRD, XPS, and simulation calculations using the Adsorption Locator and CASTEP module of BIOVIA Materials Studio based on density functional theory (DFT). On the macroscopic scale, iodide ions covered by molten salt diffused the surface of HNPC@NF through physisorption and occluded in the pores. On the atomic scale, charge-shift bonds formed between carbon atoms and iodide ions, allowing for stable adsorption at the hollow sites within the carbon network. The coexistence of cations increased the adsorption energy of iodide ions, which benefited the reaction. Based on these results, HNPC@NF showed the potential application as an adsorbent for radioactive iodide in the fluoride molten salt system.

Interaction between Groundwater and Surface Water in the Qujiang River Basin in China: Evidence from Chemical Isotope Measurements

The Qujiang River Basin is a significant water system located in Zhejiang Province, China, that serves as a primary water source for Quzhou City. For this research, we collected and examined water samples from the Qujiang River Basin. In this study, we collected and analyzed water samples from the Qujiang River Basin and employed a combination of methods, including water balance analysis; Piper trilinear diagram; Gibbs diagram; and environmental tracer techniques, such as hydrochemical and isotopic analysis. These techniques helped us to analyze the spatial distribution patterns and evolutionary trends of surface water and groundwater hydrochemistry, along with the stable isotopes of hydrogen and oxygen, as well as to determine the sources of surface water and groundwater by calculating the conversion ratio between surface water and groundwater. (1) The findings of our study indicate that the primary hydrochemical types in the study area are Ca-HCO3 and Ca-HCO3·Cl, with the ion composition of water primarily influenced by rock weathering and precipitation. (2) Similar spatial variations in hydrochemical indicators were observed between surface water and groundwater in the study area, with frequent transitions between the two. (3) The hydrogen and oxygen isotope content increases downstream, signifying that both groundwater and surface water in the study area are replenished by atmospheric precipitation, as supported by the relationship between hydrogen and oxygen isotopes and the meteoric water line. (4) We determined that groundwater predominantly replenishes surface water in the upstream area. The average contribution rate of groundwater to surface water is 19.67%, with an annual average recharge volume of 1.23 × 106 m3. Midstream and downstream, surface water mainly recharges groundwater, with an average contribution rate of 22.77% and an annual average recharge volume of 1.59 × 106 m3.

Application of 137Cs tracer technique in floodplain deposition research in mesoscale river basins

Floodplain deposition can provide important historical information about river systems. 137Cs tracer measurement is the most widely used technique for studying floodplain deposition. One-time sampling is normally used to date or estimate erosion and deposition rates, while time-interval sampling has rarely been applied. Northeast China is an important grain production area characterized by intense erosion and a low sediment transport ratio. Most studies of the region have focused on slope sedimentation, while floodplain sedimentation has received little attention. In this study, two-time steps of cross-sectional sediment core sample collection were performed to examine the floodplain sedimentation in the river basin of the Laolai River, a tributary of the Songhua River. The potential for using 137Cs to estimate the sediment deposition rate for a given time-interval was also investigated. A total of 18 cross-sections were acquired, and three repeated cross-sections were selected for double sampling. Significant differences were observed between the results obtained from the samples collected in separate rounds, suggesting the presence of internal heterogeneity during floodplain sedimentation and a significant influence of sampling positions on the analysis results. In the basin examined, sedimentation often occurs midstream, upstream, and at the outlet, and was mainly affected by topography, reservoir construction, and land use. Sedimentation occurs easily at wide, flat outlets or river intersections in braided water systems. It was observed that downstream floodplain sedimentation was increased by sediment interception by upstream reservoirs, but reduced by forests near floodplains. Sedimentation rates were significantly different between the 1954 and 1963 time markers, and we found that using rates from 1954 alone would lead to underestimation. When 137Cs sedimentation and floodplain distribution are used to determine flooding occurrence, variations in 137Cs content and particle size distribution should be considered. River bank erosion in this region should be taken into account, and riparian protection is required to reduce erosion and floodplain deposition. Since 137Cs is absent in fine particles when the sediment is predominantly sand, 137Cs measurement may underestimate the sediment deposition rate.

Исследование факторов риска развития катаракты нерадиационной природы у лиц, подвергшихся хроническому радиационному воздействию

Relevance. Epidemiological data have revealed a significant association between exposure to ionizing radiation, loss of lens optical function, and cataract formation. Cataract is a multifactorial disease that is traditionally associated with age, exposure to ultraviolet radiation, diabetes, smoking, alcohol abuse, obesity, steroid hormones, hypertension, etc. The chronic nature of the effects of radiation on the body, including both cell damage and regenerative processes, complicates the issue of assessment of the nature and magnitude of the dose-dependence of effects. Purpose. To investigate the potential risk factors of cataract development in different morphological layers, depending on social conditions and several diseases (non-radiation factors) in the population affected by two radiation accidents (dumping of radioactive waste into the Techa River and the East Ural Radioactive Trace) in the Southern Urals. Material and methods. The data from an in-depth examination of patients by an ophthalmologist in the Clinical Department of the URCRM were analyzed. The study involved 1377 patients. The «case» and «control» groups, comparable in sex and age, were selected from the general population. The impact of each factor was assessed on the basis of the Odds Ratio (OR) indicator. Risk factors associated with the development of cataracts in different layers of the lens included arterial hypertension, body mass index, age at the onset of exposure, level of education, alcohol consumption, smoking, ethnicity. Results. An increased risk of developing cataracts in the lens nucleus (1st sample: OR=0.54 (1st sample: 95% CI: 0.34–0.86; 2nd sample: OR=0.51 (95% CI: 0.32–0.82) (p&lt;0.05)) and the intensity of its color (1st sample: OR=0.48 (95% CI: 0.29–0.80); 2nd sample: OR=0.56 (95% CI: 0.34–0.94) (p&lt;0.05)) was established in persons who were at the age over 6 at the onset of exposure. Conclusion. The analysis did not reveal a statistically significant relationship of changes in the cortical layers, the nucleus and the posterior capsule of the lens with other studied risk factors in persons exposed to chronic radiation at a low to medium dose range. There was an increased risk of cataract development in the lens nucleus and the intensity of its color in persons who began to be exposed at the age of over 6 years. Key words: risk factors, cortical cataract, nuclear cataract, posterior subcapsular cataract, chronic exposure