Search Results (93)

Temperature Swing Absorption (TSA) is the primary candidate for the Isotope Rebalancing and Protium Removal (IRPR) system within the envisioned EU-DEMO fusion reactor fuel cycle. TSA separates a mixed hydrogen isotope stream into two product streams using a semi-continuous process. One stream, enriched in heavy isotopes, is used to re-establish the required deuterium-to-tritium fuel ratio. The second, enriched in protium, is stripped off from the fuel cycle to counteract the protium build-up. Separation is achieved by cycling an isotope mixture between two columns filled with metallic absorption materials that have opposite isotope effects of metal hydride formation. The selection of these materials, the operation parameters and the column geometry allow for adjusting the resulting enrichments. To identify suitable operation parameters, a TSA process model is developed which depicts the process dynamics and interactions between the columns. A modified process operation mode is introduced, which enables higher system throughputs and non-cryogenic operation, i.e., operational temperatures between 0 to 130 °C, while reducing the tritium inventory due to shorter cycling times by reduced amplitudes of the temperature swings. Finally, simulations of a TSA system at relevant scale confirm the suitability of TSA technology for the separation task of the EU-DEMO IRPR system. Full article

The oxidation of sulfide minerals in the presence of oxygen and water, facilitated by microbes, is the principal cause of acid mine drainage (AMD). Static testing for the quantitative assessment of the acidic potential and acid-neutralizing capacity of mineral samples has been thoroughly investigated; the extent of its accuracy remains uncertain. This study involved 329 ore samples from 34 drill holes from abandoned mining sites and conducted laboratory static tests and mineralogical analysis. Static testing and mineralogical characterization identified a significant positive correlation between total sulfur and net acid generation (NAG), confirming that sulfide oxidation is the dominant mechanism for acid production. Furthermore, the strong positive correlation between calcium content and acid-neutralizing capacity (ANC) demonstrates that the buffering capacity stems mainly from carbonate dissolution, with negligible contribution from silicate weathering. The effectiveness of a detailed acid-generating potential discrimination chart was also assessed. Through the examination of acid drainage samples and groundwater from the research area, with their stable isotope and Deuterium excess (D-excess) properties, hydrochemical classifications were established, and sources of acid drainage were evaluated. This comprehensive method pinpoints the main “acid-generating sources” in the abandoned mining sites, elucidating the geochemical origins of acid drainage in the research area. It offers a case study and analytical framework for employing static test findings from abandoned mining sites to evaluate acid-generating potential in those areas. Full article

Chemical incompatibility between active pharmaceutical ingredients (APIs) and mineral supplements may affect their bioavailability and effectiveness. Water, as the main component of physiological fluids, plays a crucial role in these interactions. Natural waters vary in the deuterium. Estimation of the kinetic isotope effect (KIE) provides valuable information on reaction mechanisms in solvents with different D/H ratios and with the replacement of protium with deuterium in API molecules. Studies of the kinetics of interactions between zinc ions and amoxicillin in water with a natural isotopic composition (D/H = 145 ppm) and in heavy water (99.9% D₂O) offer a model for predicting similar interactions in vivo. The presence of chiral centers in the amoxicillin molecule allowed the use of polarimetry to study the influence of the solvent isotopic composition, temperature, and pH on the rate of interaction. In heavy water, a twofold decrease in the rate of amoxicillin binding to hydrated zinc ions was observed compared to natural water at 20 °C. Arrhenius kinetics confirmed the observed KIE: Ea = 112.5 ± 1.3 kJ/mol for D₂O and 96.0 ± 2.1 kJ/mol for H₂O. For the first time, kinetic polarimetric studies demonstrated differences in the mechanisms of binding of d- and s-element cations to amoxicillin. Full article

High concentrations of hydrogen isotopes have been observed at the ends of CANDU Zr-2.5Nb pressure tubes in the region associated with the rolled joints with 403 stainless steel end fittings. These concentrations are above current regulatory limits, causing concerns over how long pressure tubes should remain in service. This paper reviews two differing interpretations of the mechanisms for these high concentrations, leading to two conclusions. Ingress after about 30 y is attributed to pressure tube sag creating a crevice between the end fitting and the top of the tube that provides a window for hydrogen isotopes to enter from the annulus gas under reducing conditions. Small additions of oxygen should close this window. A new mechanism is suggested to explain deuteride precipitates past the rolled joint contact region after about 30 y. Surprisingly, the mechanism relies on deuterium and protium diffusing in solution at the same rate, i.e., no mass-dependent isotope effect. Full article

Deuterium, a stable isotope of hydrogen present in natural water at ~150 ppm, has been implicated in modulating cellular metabolism and tumor progression. While deuterium-depleted water (DDW) has shown anti-cancer effects in preclinical and clinical studies, the underlying transcriptional mechanisms remain incompletely defined. Here, we profiled gene expression in A549 lung adenocarcinoma cells cultured for 72 h in media containing four graded deuterium concentrations (40, 80, 150, and 300 ppm) using a targeted NanoString panel of 236 cancer-related genes. After stringent quality filtering, 87 genes were retained and classified into nine distinct expression patterns based on fold-change trends relative to the 150 ppm control. High deuterium (300 ppm) induced strong upregulation (up to 2.1-fold) of oncogenic and survival-related genes (e.g., EGFR, CTNNB1, STAT3, CD44), while DDW (40–80 ppm) led to selective downregulation (down to 0.58-fold) of oncogenes (e.g., MYCN, ETS2, IRF1) and drug-resistance genes (e.g., ABCB1). Se-veral genes involved in DNA repair, apoptosis, and extracellular matrix remodeling exhibited dose-dependent responses, suggesting coordinated regulation by deuterium abundance. These findings demonstrate that deuterium concentration functions as a biologically active variable capable of modulating cancer-relevant gene networks. This exploratory dataset refines mechanistic models of DDW action and provides a foundation for future studies incorporating biological replication, functional assays, and in vivo validation. Significance: Deuterium concentration modulation alters oncogenic, apoptotic, and drug-resistance gene networks in lung adenocarcinoma cells, refining prior models of deuterium-depleted water effects. These findings identify deuterium concentration as a biologically active variable warranting further mechanistic and translational investigation. Full article

Background: The isotopic composition of the body’s internal environment can affect its functional state. Such effects are realized, among other things, by inserting deuterium atoms into hydrogen bonds between pairs of nitrogenous bases of DNA molecules and modifying their mechanical properties. Methods: This study uses a coarse-grained mathematical model of DNA. Results: It has been established that in a certain range of the magnitude of the torque, with the presence of a deuterium atom within it, stabilization of the CAG repeat tract is observed. In addition, it was found that, regardless of which base pair the deuterium atom falls into in the CAG repeat tract, its stability increases and the probability of hairpin formation decreases, which may interfere with the reading of genetic information from the site encoding glutamine. Conclusions: Single H/D substitutions in the CAG repeat tract of the ATXN2 gene increase its stability by reducing the formation of open states, regardless of the position of deuterium. Full article

The study of molecular mechanisms underlying late-life depression (LLD) is increasingly important in light of population aging. To date, LLD-related molecular brain changes remain poorly understood. Furthermore, environmental factors such as climate change and geography contribute to LDD risks. One overlooked factor might be deuterium—a stable hydrogen isotope—whose concentration in drinking water can vary geographically (~90–155 ppm) and alter the incidence of mood disorders. Conversely, potential effects of natural variations in deuterium content in drinking water on LLD symptoms and brain gene expression remain unknown. We conducted Illumina gene expression profiling in the hippocampi and prefrontal cortexes of 18-month-old C57BL/6J mice, a model of LLD-like behaviors, compared to 3-month-old controls. Separately, aged mice were allowed to consume deuterium-depleted (DDW, ~90 ppm) or control (~140 ppm) water for 21 days and were studied for LLD-like behaviors and Illumina gene expression of the brain. Naïve old mice displayed ≥2-fold significant changes of 35 genes. Housing on DDW increased their hedonic sensitivity and novelty exploration, reduced helplessness, improved memory, and significantly altered brain expression of Egr1, Per2, Homer1, Gadd45a, and Prdx4, among others. These genes revealed significant alterations in several GO-BP and KEGG pathways implicated in inflammation, cellular stress, synaptic plasticity, emotionality, and regeneration. Additionally, we found that incubation of primary neuronal cultures in DDW-containing buffer ameliorated Ca²⁺ influx and mitochondrial potential in a toxicity model, suggesting the involvement of mitochondrial mechanisms in the effects of decreased deuterium levels. Thus, aging induced profound brain molecular changes that may at least in part contribute to LLD pathophysiology. Reduced deuterium intake exerted modest but significant effects on LLD-related behaviors in aged mice, which can be attributed to, but not limited by ameliorated mitochondrial function and changes in brain gene expression. Full article

Ultrafine particles (UFPs) containing polycyclic aromatic hydrocarbons (PAHs) benzo[a]pyrene (BaP), are linked to pollution-induced health concerns, with skin being highly susceptible to contamination. Understanding the metabolic fate of these environmental pollutants in the skin is crucial. Moreover, traditional in vitro models often lack metabolic competency, while animal testing raises ethical concerns. This study introduces a novel approach combining stable isotope labeling (SIL) and liquid chromatography–high-resolution mass spectrometry (LC-HRMS) to investigate BaP metabolism. The physiologically relevant 3D reconstructed human epidermis (RHE) model was used. RHE models were exposed to BaP and deuterium-labeled BaP (BaP-d12). These analyses, followed by data analysis incorporating stable isotope filtering, revealed the presence of five distinct BaP phase I metabolites, including mono-hydroxylated, dihydroxylated, and quinone derivatives. This study demonstrates the power of coupling stable isotope labeling with LC-HRMS for the comprehensive characterization of BaP metabolic pathways in human skin. The identification of specific metabolites enhances our understanding of BaP detoxification mechanisms and their potential adverse effects. This analytical approach holds promise for investigating the metabolic fate of various other environmental pollutants. Full article

Proteins and peptides are vital biomolecules, and deuterated amino acids are increasingly applied in areas such as drug discovery, metabolic tracing, and neutron scattering studies. In this study, we performed deuteration on all 20 proteinogenic amino acids, including their side chains, and established efficient methods for 13 amino acids. Using a Pt/C-catalyzed hydrogen–deuterium exchange reaction, the reaction parameters were optimized to achieve the selective and stable incorporation of deuterium. In addition, the resulting deuterated compounds, focusing on tryptophan, were characterized in order to assess their physicochemical properties. Because the deuteration reaction caused significant racemization of amino acids, deuterated D/L-tryptophan was isolated using a chiral separation method. Deuterated tryptophan characterization studies confirmed that the photostability was markedly enhanced by deuteration, whereas the acid stability showed no clear isotopic effect. The X-ray crystal structure analyses revealed minimal changes upon the hydrogen-to-deuterium substitution. These results provide a robust platform for the supply of deuterated amino acids, facilitating their application in drug development, structural analysis, and creation of advanced functional biomaterials. Full article

Water is a vital nutrient that is needed to maintain almost all biological processes in living organisms. The natural water contains two isotopes of hydrogen—protium and deuterium. Deuterium, the trace component of natural water, significantly changes its physical and chemical properties and biological action. In this review, the authors summarize data on the isotopic effects of deuterium and discuss the possible magnetic effects of isotopes and the molecular basis of the biological effects of deuterium-depleted water. The review also presents new data on the already known and potential use of deuterium-depleted water in medicine (oncology, neurology) and previously unknown new directions of its use (immunological and endocrine disorders, anemia). Based on the analysis of collected data, the authors presented mechanisms of action of deuterium-depleted water in the organism. The authors also identified the least-studied effects of deuterium-depleted water, particularly its influence on morphogenetic processes. The review discloses the perspectives on deuterium-depleted water as a tool for therapy and substantiates the risks of its uncontrolled intake. Full article

The application of natural radioisotope and stable isotope tracing represents a novel, sensitive method for confirming the presence of environmental contamination due to leachate water from solid waste landfills. This study aimed to employ this approach to assess the efficiency of containment measures and the potential environmental impact in the vicinity of a landfill designated for non-hazardous waste disposal. We collected leachate water samples from two distinct areas: one currently active, and another exhausted. In February, May, August, and November 2022, we collected deep water samples from a nearby stream utilizing piezometers, both upstream and downstream from the facility. We examined deuterium and tritium radioisotopes via liquid scintillation, and stable isotope oxygen-18 via ratio mass spectrometry. The results revealed the presence of anthropogenic radioisotopes within the landfill, with higher concentrations in the active site. No radioisotopes or stable isotopes above the natural background were identified in any of the samples obtained from outside. The levels of tritium were found to correlate with rainfall in the samples collected inside, but not in those obtained outside. These findings provide evidence of the effectiveness of the active structural, managerial, and procedural containment measures and the absence of environmental contamination stemming from the studied site, reinforcing the value of the responsible management of non-hazardous waste and its limited impact on the surrounding environment. The reported results highlight the utility of performing radioisotope and stable isotope monitoring not only inside but also outside the landfill, and analyzing the relation via pluviometry. Full article

Charge-free gaseous molecules labeled with deuterium ²H (D) atoms elute earlier than their protium-analogs ¹H (H) from most stationary GC phases. This effect is known as the chromatographic H/D isotope effect (hdIE_C) and can be calculated by dividing the retention times (t_R) of the protiated (t_R(H) ) to those of the deuterated (t_R(D)) analytes: hdIE_C = t_R(H)/t_R(D). Analytes labeled with ¹³C, ¹⁵N or ¹⁸O have almost identical retention times and lack a chromatographic isotope effect. Derivatives of cis- and trans-analytes such as cis- and trans-fatty acids also differ in their retention times. Analytes that contain trans-C=C-double bonds elute earlier in gas chromatography-mass spectrometry (GC-MS) than their cis-C=C-double bonds containing congeners. The chromatographic cis/trans-effect (ctE_C) can be calculated by dividing the retention times of the cis- by those of the trans-analytes: ctE_C = t_R(c)/t_R(t). In the present work, the hdIE_C and ctE_C values of endogenous and exogenous substances were calculated from previously reported GC-MS analyses and found to range each between 1.0009 and 1.0400. The examination suggests that the H/D-isotope effects and the cis/trans-effects observed in GC-MS are based on differences in the inter-molecular interaction strengths of the analyte derivatives with the stationary phase of GC columns. The deuterium atoms, being larger than the H atoms of the analytes, attenuate the interaction of the skeleton of the molecules with the GC stationary phase. The angulation of trans-analytes decreases the interaction of the skeleton of the molecules with the GC stationary phase, as only parts of the molecules are close enough to the GC stationary phase to interact. Other chromatographic effects caused by hydrogen (H) and fluorine (F) atoms and by stereo-isomerism are considered to be based on a similar mechanism due to the different orientation of the side chains. Full article

Heavy water (D₂O) is scarce in nature, and despite its physical similarity to water, D₂O disrupts cellular function due to the isotope effect. While microbes can survive in nearly pure D₂O, eukaryotes such as Arabidopsis thaliana are more sensitive and are unable to survive higher concentrations of D₂O. To explore the underlying molecular mechanisms for these differences, we conducted a comparative proteomic analysis of E. coli, S. cerevisiae, and Arabidopsis after 180 min of growth in a D₂O-supplemented media. Shared adaptive mechanisms across these species were identified, including changes in ribosomal protein abundances, accumulation of chaperones, and altered metabolism of polyamines and amino acids. However, Arabidopsis exhibited unique vulnerabilities, such as a muted stress response, lack of rapid activation of reactive oxygen species metabolism, and depletion of stress phytohormone abscisic acid signaling components. Experiments with mutants show that modulating the HSP70 pool composition may promote D₂O resilience. Additionally, Arabidopsis rapidly incorporated deuterium into sucrose, indicating that photosynthesis facilitates deuterium intake. These findings provide valuable insights into the molecular mechanisms that dictate differential tolerance to D₂O across species and lay the groundwork for further studies on the biological effects of uncommon isotopes, with potential implications for biotechnology and environmental science. Full article

This study investigated the basement aquifer beneath the urbanised city of Niamey and the agricultural fields of Kollo, SW of Niger. During the observation period spanning from 2021 to 2023, groundwater and surface water samples were collected for analysis of major ions and the stable isotopes oxygen-18 and deuterium (δ¹⁸O and δ²H) of water. To trace the origin of high nitrate concentrations (NO₃⁻) found in several observation and drinking water wells in both areas, δ¹⁵N and δ¹⁸O isotope values of NO₃⁻ were analysed in groundwater and eluted soil samples. The observed hydrochemical patterns mainly reflect the heterogeneity of the weathered fringe of the basement aquifer. Decreasing concentrations of NO₃⁻ and δ¹⁸O and δ²H values were observed in relation to the distance of the Niger River and increasing thickness of the clay layer on the surface. The wells close to the river in Niamey show a dilution effect during the flood season, and the NO₃⁻ concentrations displayed a continuous increasing trend. The δ¹⁵N-NO₃ and δ¹⁸O-NO₃ values confirmed that septic tank water is spreading in the region of Niamey and that manure originating from livestock in Kollo is the main source of NO₃⁻. The patterns of δ¹⁵N in the soil samples coincide with those of cattle’s manure spread in both areas. The shallow wells show significantly higher values of electric conductivity and NO₃⁻ concentrations compared to the deeper wells, which clearly indicates the influence of shallow septic tanks on water quality. Full article

Background: Our study presented a novel LC-MS/MS method for the simultaneous quantification of α-tocopherol (α-TOH) and its phase II metabolites, α-13′-COOH and α-13′-OH, in human serum using deuterium-labeled internal standards (d₆-α-TOH, d₆-α-13′-COOH, d₆-α-13′-OH). Methods: The method addresses the analytical challenge posed by the significantly different concentration ranges of α-TOH (µmol/L) and its metabolites (nmol/L). Previous methods quantified these analytes separately, which caused an increase in workflow complexity. Results: Key features include the synthesis of stable isotope-labeled standards and the use of a pentafluorophenyl-based core-shell chromatography column for baseline separation of both α-TOH and its metabolites. Additionally, solid phase extraction (SPE) with a HybridSPE^® material provides a streamlined sample preparation, enhancing analyte recovery and improving sensitivity. By utilizing deuterium-labeled standards, the method compensates for matrix effects and ion suppression. This new approach achieves precise and accurate measurements with limits of detection (LOD) and quantification (LOQ), similar to previous studies. Calibration, accuracy, and precision parameters align well with the existing literature. Conclusions: Our method offers significant advantages in the simultaneous analysis of tocopherol and its metabolites despite concentration differences spanning up to three orders of magnitude. In contrast to earlier studies, which required separate sample preparations and analytical techniques for tocopherol and its metabolites, our approach streamlines this process. The use of a solid-phase extraction procedure allows for parallel sample preparation. This not only enhances efficiency but also significantly accelerates pre-analytical workflows, making the method highly suitable for large-scale studies. Full article