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Marine-derived proteins, such as blue whiting-derived protein hydrolysates (BWPH), represent high-quality sources of dietary protein, but their ability to support postexercise anabolism is not established. The impact of BWPH on whole-body anabolism was compared with an isonitrogenous whey protein isolate (WPI) and nonessential amino acid (NEAA) control in 10 trained young males (31 ± 4 years) who, on three separate visits, performed a session of whole-body resistance exercise and then consumed, in randomized crossover fashion, BWPH, WPI, or NEAA (0.33 g/kg; 19, 33, and 0 mg/kg leucine, respectively) with L-[1-13C]leucine. Breath, blood, and urine samples were collected for 6-hr postprandial to assess dietary leucine oxidation, amino acid (AA) concentrations, and 3-methylhistidine: creatinine ratio. Peak and area under the curve concentrations for leucine, branched-chain amino acids, and essential amino acids were greater in WPI compared with BWPH (all p <.05) but with no differences in time to peak concentration. Total oxidation reflected leucine intake (WPI > BWPH > NEAA; p <.01), whereas relative oxidation was greater (p <.01) in WPI (28.6 ± 3.6%) compared with NEAA (21.3 ± 4.2%), but not BWPH (28.6 ± 8.8%). Leucine retention, a proxy for whole-body protein synthesis, was greater in WPI (185.6 ± 9.5 μmol/kg) compared with BWPH (109.3 ± 14.1 μmol/kg) and NEAA (5.74 ± 0.30 μmol/kg; both p <.01), with BWPH being greater than NEAA (p <.01). Urinary 3-methylhistidine: creatinine ratio did not differ between conditions. Both WPI and BWPH produced essential aminoacidemia and supported whole-body anabolism after resistance exercise, but a higher intake of BWPH to better approximate the leucine and EAA content of WPI may be needed to produce an equivalent anabolic response. Consuming protein after exercise is generally considered to be important for recovery from a single session of exercise, and over time can support muscle growth in response to long-term strength training. This study aimed to understand how different types of protein might affect these so-called "anabolic" processes by studying a marker of the body's ability to recovery and grow muscle after exercise. Specifically, this study compared how well three different protein sources—a dairy-based protein in the form of whey protein isolate, a novel fish protein powder derived from blue whiting, and a blend of what are known as nonessential amino acids—help the body retain another amino acid named leucine, which is a key indicator of muscle-building potential, during the 6 hr of recovery after exercise. There are 20 amino acids that are used in the body, some come from our food and some can be made in the body, but regardless of source, these amino acids serve as building blocks for all of the proteins in the body. Ten healthy young men who had been regularly doing strength training participated in the study. On three different occasions, each participant completed a full-body workout and then drank one of the three protein drinks. The amount of protein they consumed was based on their body weight. The drink provided 20–30 g of protein depending, on body size. After each workout, how much leucine the body retained over a 6-hr period was assessed by collecting samples of blood, breath, and urine which effectively measures how well the proteins were absorbed and used by the body for processes supporting muscle recovery, repair, and growth. One of the key questions was whether this fish-derived protein could be a good alternative to whey protein for supporting muscle recovery after exercise. Whey protein is well-known for its ability to support these processes and help build muscle, but there is much interest in whether other protein sources, particularly those from fish, could offer similar benefits. Fish proteins may also have the added advantage of being more sustainable, which is increasingly important in today's world. The nonessential amino acid blend served as a control, as it was not expected to contribute to processes that support muscle recovery and growth due to its lack of essential amino acids. The results showed that whey protein was the most effective by leading to the highest concentrations of essential amino acids in the blood, and the greatest amount of leucine retained in the body, meaning that the body was potentially able to use more of it for muscle recovery and growth. The fish protein performed better than the nonessential amino acids, supporting the idea that it could help with muscle recovery, but it was not as effective as whey protein. This finding is likely because the fish protein contained less essential amino acids, which are critical for muscle recovery and growth processes. Consuming a larger amount of the fish protein could potentially provide benefits similar to whey protein, but more studies would be needed to confirm this. The nonessential amino acid blend was the least effective, as expected, because it lacked the necessary components to stimulate these anabolic processes in muscle. The interpretation of these results is that while whey protein would be the most effective of the three protein sources for promoting muscle recovery after exercise, fish-derived proteins, like the one tested in this study, could be a good alternative, especially for those who are looking for nondairy sources of protein. While the fish protein didn't perform as well as whey protein in this study, it did still support muscle recovery, suggesting it could be a viable option to match the effects of whey if provided at the right dosage. Overall, this research adds to our understanding of how different protein sources can help the body recover after exercise, and suggests that future research could focus on how adjusting the amount of fish protein consumed could improve its potential to support recovery and growth in response to exercise. Consuming protein after exercise is generally considered to be important for recovery from a single session of exercise, and over time can support muscle growth in response to long term strength training. This study aimed to understand how different types of protein might affect these so-called "anabolic" processes by studying a marker of the body's ability to recovery and grow muscle after exercise. Specifically, this study compared how well three different protein sources—a dairy-based protein in the form of whey protein isolate, a novel fish protein powder derived from blue whiting, and a blend of what are known as nonessential amino acids—help the body retain another amino acid named leucine, which is a key indicator of muscle-building potential, during the 6 hr of recovery after exercise. There are 20 amino acids that are used in the body, some come from our food and some can be made in the body, but regardless of source, these amino acids serve as building blocks for all of the proteins in the body. Ten healthy young men who had been regularly doing strength training participated in the study. On three different occasions, each participant completed a full-body workout and then drank one of the three protein drinks. The amount of protein they consumed was based on their body weight, and so the drink provided 20–30 g of protein depending on body size. After each workout, how much leucine the body retained over a 6-hr period was assessed by collecting samples of blood, breath, and urine, and this is effectively a measure of how well the proteins were absorbed and used by the body for processes supporting muscle recovery, repair, and growth. One of the key research questions was whether this fish-derived protein could be a good alternative to whey protein for supporting muscle recovery after exercise. Whey protein is well-known for its ability to support these processes and help build muscle, but there is much interest in whether other protein sources, particularly those from fish, could offer similar benefits. Fish proteins may also have the added advantage of being more sustainable, which is increasingly important in today's world. The nonessential amino acid blend served as a control, as it was not expected to contribute to processes that support muscle recovery and growth due to its lack of essential amino acids. The results showed that whey protein was the most effective by leading to the highest concentrations of essential amino acids in the blood, and the greatest amount of leucine retained in the body, meaning that the body was potentially able to use more of it for muscle recovery and growth. The fish protein performed better than the nonessential amino acids, supporting the idea that it could help with muscle recovery, but it was not as effective as whey protein. This finding is likely because the fish protein contained less essential amino acids, which are critical for muscle recovery and growth processes. Consuming a larger amount of the fish protein could potentially provide similar benefits to whey protein, but more studies would be needed to confirm this. The nonessential amino acid blend was the least effective, as expected, because it lacked the necessary components to stimulate these anabolic processes in muscle. The interpretation of these results is that while whey protein would be the most effective of the three protein sources for promoting muscle recovery after exercise, fish-derived proteins like the one tested in this study could still be a good alternative, especially for those who are looking for nondairy sources of protein. While the fish protein didn't perform as well as whey protein in this study, it did still support muscle recovery, suggesting it could be a viable option to match the effects of whey if provided at the right dosage. Overall, this research adds to our understanding of how different protein sources can help the body recover after exercise, and suggests that future research could focus on how adjusting the amount of fish protein consumed could improve its potential to support recovery and growth in response to exercise. [ABSTRACT FROM AUTHOR]

Water shows anomalous properties that are enhanced upon supercooling. The unusual behavior is observed in both H2O and D2O, however, with different temperature dependences for the two isotopes. It is often noted that comparing the properties of the isotopes at two different temperatures (i.e., a temperature shift) approximately accounts for many of the observations—with a temperature shift of 7.2 K in the temperature of maximum density being the most well-known example. However, the physical justification for such a shift is unclear. Motivated by recent work demonstrating a "corresponding-states-like" rescaling for water properties in three classical water models that all exhibit a liquid–liquid transition and critical point [Uralcan et al., J. Chem. Phys. 150, 064503 (2019)], the applicability of this approach for reconciling the differences in the temperature- and pressure-dependent thermodynamic properties of H2O and D2O is investigated here. Utilizing previously published data and equations-of-state for H2O and D2O, we show that the available data and models for these isotopes are consistent with such a low temperature correspondence. These observations provide support for the hypothesis that a liquid–liquid critical point, which is predicted to occur at low temperatures and high pressures, is the origin of many of water's anomalies. [ABSTRACT FROM AUTHOR]

Light and heavy water show similar anomalies in thermodynamic and dynamic properties, with a consistent trend of anomalies occurring at higher temperatures in heavy water. Viscosity also increases faster upon cooling in heavy water, causing a giant isotope effect, with a viscosity ratio near 2.4 at 244 K. While a simple temperature shift apparently helps in collapsing experimental data for both isotopes, it lacks a clear justification, changes value with the property considered, and requires additional ad hoc scaling factors. Here, we use a corresponding states analysis based on the possible existence of a liquid–liquid critical point in supercooled water. This provides a coherent framework that leads to the collapse of thermodynamic data. The ratio between the dynamic properties of the isotopes is strongly reduced. In particular, the decoupling between viscosity η and self-diffusion D, measured as a function of temperature T by the Stokes–Einstein ratio Dη/T, is found to collapse after applying the corresponding states analysis. Our results are consistent with simulations and suggest that the various isotope effects mirror the one on the liquid–liquid transition. [ABSTRACT FROM AUTHOR]

Present and future climatic trends are expected to markedly alter water fluxes and stores in the hydrologic cycle. In addition, water demand continues to grow due to increased human use and a growing population. Sustainably managing water resources requires a thorough understanding of water storage and flow in natural, agricultural, and urban ecosystems. Measurements of stable isotopes of water (hydrogen and oxygen) in the water cycle (atmosphere, soils, plants, surface water, and groundwater) can provide information on the transport pathways, sourcing, dynamics, ages, and storage pools of water that is difficult to obtain with other techniques. However, the potential of these techniques for practical questions has not been fully exploited yet. Here, we outline the benefits and limitations of potential applications of stable isotope methods useful to water managers, farmers, and other stakeholders. We also describe several case studies demonstrating how stable isotopes of water can support water management decision-making. Finally, we propose a workflow that guides users through a sequence of decisions required to apply stable isotope methods to examples of water management issues. We call for ongoing dialogue and a stronger connection between water management stakeholders and water stable isotope practitioners to identify the most pressing issues and develop best-practice guidelines to apply these techniques.

Nitrous oxide (N2O), a potent greenhouse gas, can be generated by multiple biological and abiotic processes in diverse contexts. Accurately tracking the dominant sources of N2O has the potential to improve our understanding of N2O fluxes from soils as well as inform the diagnosis of human infections. Isotopic Site Preference (SP) values have been used toward this end, as bacterial and fungal nitric oxide reductases (NORs) produce N2O with different isotopic fingerprints, spanning a large range. Here, we show that flavohemoglobin (Fhp), a hitherto biogeochemically neglected yet widely distributed detoxifying bacterial NO reductase, imparts a distinct SP value onto N2O under anoxic conditions (~+10‰) that correlates with typical environmental N2O SP measurements. Using Pseudomonas aeruginosa as a model organism, we generated strains that only contained Fhp or the dissimilatory NOR, finding that in vivo N2O SP values imparted by these enzymes differ by over 10‰. Depending on the cellular physiological state, the ratio of Fhp:NOR varies significantly in wild-type cells and controls the net N2O SP biosignature: When cells grow anaerobically under denitrifying conditions, NOR dominates; when cells experience rapid, increased nitric oxide concentrations under anoxic conditions but are not growing, Fhp dominates. Other bacteria that only make Fhp generate similar N2O SP biosignatures to those measured from our P. aeruginosa Fhp-only strain. Fhp homologs in sequenced bacterial genomes currently exceed NOR homologs by nearly a factor of four. Accordingly, we suggest a different framework to guide the attribution of N2O biological sources in nature and disease.

The present study reveals the effects of symmetry on how the distribution and flow of energy play out on the decomposition of small halocarbons. Unimolecular decay of the freons CHFCl2 and CF2Cl2 when ionized has been investigated. Mass spectrometric results that encompass isotope effects (peak heights) and energy distribution in the exit channel (peak shapes) are interpreted by computational methods. Non-statistical processes of electronic predissociation and isolated state decay are shown to be directly associated with molecular symmetry. [ABSTRACT FROM AUTHOR]

Beryllium isotopes (stable 9Be and cosmogenic meteoric 10Be) enter the oceans through distinct pathways – i.e., from the continents and the atmosphere respectively – and display non-conservative behaviour in seawater. This isotope system has served as a powerful tool for quantifying a variety of processes, including geomagnetism, sedimentation, continental input, and ocean circulation. However, processes at land–ocean boundaries and within the ocean interior may either amplify or buffer the seawater isotope response to environmental changes. In the last decade, substantial effort has been invested in understanding external sources and internal cycling of Be isotopes, offering an excellent opportunity to revisit their modern oceanic cycle. Here, we investigate the controls on the modern oceanic cycling of Be isotopes using a three-dimensional ocean model, constrained by observational data on input fluxes and water-column distributions of 9Be and 10Be. In addition to modelling the previously known controls, we highlight the key role of marine benthic fluxes and scavenging onto particulate organic matter and opal in determining the mass balance and spatial distribution of Be isotopes. Inter-basin Be transport by the circulation is less important than external inputs at continent/atmosphere–ocean boundaries, except in the South Pacific. Therefore, the distribution of seawater 10Be/9Be ratios largely reflects that of the external inputs in most basins in the modern ocean. Finally, we apply our data-constrained mechanistic model to test the sensitivity of basin-wide 10Be/9Be ratios to changes of external sources and internal cycling. This analysis shows that seawater 10Be/9Be ratios are to some extent buffered against changes in continental denudation. For example, a 50 % decrease in denudation rates results in a 13–48 % increase in ocean-wide 10Be/9Be ratios. Moreover, the interplay between particle scavenging and ocean circulation can cause divergent responses in 10Be/9Be ratios in different basins. Weaker scavenging (e.g., 50 % decrease in intensity) would increase the homogenising effect of ocean circulation, making North Atlantic and North Pacific 10Be/9Be ratios converge (∼20 % change in isotope ratios). The mechanistic understanding developed from this Be cycling model provides important insights into the various applications of marine Be isotopes, and offers additional tools to assess the causes of spatio-temporal Be isotope variations. We also identify the key oceanic processes that require further constraints to achieve a complete understanding of Be cycling in the modern ocean and back through time. [ABSTRACT FROM AUTHOR]

Here, we present the North American Repository for Archaeological Isotopes (NARIA), the largest open-access compilation of previously reported isotopic measurements (n = 28,374) from bioarchaeological samples in North America (i.e., Canada, Greenland, Mexico, and the United States of America) covering a time-frame of more than 12,000 years. This database consists of stable (δ13C, δ15N, δ18O) and radiogenic (87Sr/86Sr) isotope measurements from archaeological human, animal, and plant sources and their corresponding contextual information (e.g., location, chronology, cultural affiliation, etc.). This synthesis of isotopic measurements and other forms of data presents significant research potential for investigating past human lifeways, particularly in the realms of paleomobility, paleoenvironment, and paleodiet. Additionally, it serves to pinpoint spatial and temporal data gaps, offering valuable insights for future research directions. [ABSTRACT FROM AUTHOR]

Calcium‐aluminum‐rich inclusions (CAIs) are the first objects that formed in the solar accretion disk and therefore provide valuable insights into the evolution of the early solar system. A long‐standing question regarding this earliest formative period relates to the storage of CAIs in the 1–4 Myr time period between their formation and later accretion into chondrite parent bodies. Were the CAIs stored in a pre‐existing parent body, or in distant parts of the solar accretion disk? In the latter scenario, CAIs might have been exposed to cosmic rays, either from the galaxy or from the Sun and such pre‐accretion irradiation effects might be detectable. We searched for such pre‐accretional irradiation effects in 7 fine‐ and 11 coarse‐grained CAIs from the CV 3.6 carbonaceous chondrite Allende. The extracted samples were analyzed for their major chemical composition and all samples were analyzed using μCT techniques. Using physical model calculations, 21Necos and (22Ne/21Ne)cos production rate ratios were calculated for each CAI by fully considering their individual chemical composition. Measured He, Ne, Ar, and Kr isotope compositions of the CAIs show cosmogenic signals; clear signals for He and Ne isotopes; and detectable signals for some of the Ar and Kr isotopes. In addition, most samples show clear indications for radiogenic 4He and some samples show evidence for radiogenic 40Ar. Higher 36Ar/38Ar, 22Ne/21Ne, 80Kr/84Kr, and 82Kr/84Kr ratios together with lower cosmogenic 38Arcos concentrations in fine‐grained CAIs compared to coarse‐grained CAIs are consistent with more alteration of the former compared to the latter. The CRE ages for the CAIs range between 4.12 ± 0.41 Myr and 6.40 ± 0.63 Myr. Statistical tests indicate that the data are normally distributed with no outliers, indicating that all CAIs share a common irradiation history, likely the irradiation in the Allende meteoroid. The average CRE age of 4.87 ± 0.19 Myr agrees with the nominally accepted CRE age of Allende of ~5.2 Myr. There is no correlation between 21Necos concentrations and indicators of aqueous alteration like Na and/or U concentrations. The lack of correlation together with the finding of normally distributed modeled CRE ages indicates that either none of the studied CAIs experienced a pre‐accretion irradiation before parent body compaction and/or that any pre‐accretion irradiation effects have been completely erased during aqueous alteration events. Taking alteration aside, the findings are not in favor of X‐wind type models but are more consistent with the idea of CAI outward transport in an expanding disk. [ABSTRACT FROM AUTHOR]

Atomic nuclei serve as prime laboratories for investigations of complex quantum phenomena, where minor nucleon rearrangements cause significant structural changes. 190Pb is the heaviest known neutron-deficient Pb isotope that can exhibit three distinct shapes: prolate, oblate, and spherical, with nearly degenerate excitation energies. Here we report on the combined results from three state-of-the-art measurements to directly observe these deformations in 190Pb. Contrary to earlier interpretations, we associate the collective yrast band as predominantly oblate, while the non-yrast band with higher collectivity follows characteristics of more deformed, predominantly prolate bands. Direct measurement of the E 0 ( 0 2 + → 0 1 + ) transition and γ-e− coincidence relations allowed us to locate and firmly assign the 0 2 + state in the level scheme and to discover a spherical 2 3 + state at 1281(1) keV with B (E 2 ; 2 3 + → 0 1 + ) = 1.2 (3) W.u. These assignments are based purely on observed transition probabilities and monopole strength values, and do not rely on model calculations for their interpretation. Direct measurements reveal that the neutron-deficient isotope 190Pb can adopt three different deformations near the ground state. The present work identifies the collective yrast band as predominantly oblate, the non-yrast band as predominantly prolate, and discovers a candidate spherical 2 3 + state at 1281 keV. [ABSTRACT FROM AUTHOR]

The paper considers the concentration of 95–97Mo in a square cascade with large stage separation coefficients corresponding to gas centrifuges. Cascades were calculated using a method for varying the sections of partial stage streams and minimizing the deviation of calculated stage feeding streams from the specified one. A computational experiment on the multi-step separation of a molybdenum hexafluoride mixture was carried out. Isotopes of 95–97Mo can be efficiently concentrated in a single square cascade. In streams depleted of these isotopes, isotopically modified molybdenum is accumulated for use as a structural material for fuel element claddings having improved thermophysical characteristics. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare the level of bone mass in digital orthopantomograms in two populations (medieval and current) using two radiomorphometric indexes, and to correlate the mandibular bone mass value, in the medieval mandible population, with stable isotope data δ13C and δ15N. An observational, cross-sectional, and analytical study on mandibles from two diachronic groups, 15 mandibles from the medieval settlement of La Torrecilla (Granada, Spain) and 15 mandibles from current patients at the Faculty of Dentistry of the University of Granada (Spain), matched by age and sex was conducted. The bone mass density was determined using the Mandibular Cortical Width Index (MCW) and the Mandibular Panoramic Index (PMI) in digital panoramic radiographs. In the medieval group, the values of bone mass density were correlated with those of two stable isotopes (δ13C and δ15N). The mean value of MCW in mm in the medieval group was 3.96 ± 0.60 (mean ± standard deviation) and in the current group was 4.02 ± 1.01. The PMI was 0.33 ± 0.06 and 0.35 ± 0.08 in the medieval and current groups respectively, with similar results in both groups (p = 0.820 and p = 0.575). A negative correlation was found between both morphometric indices and the δ15N isotope (rs = 0.56, p = 0.030 and rs = 0.61, p = 0.016, respectively). The bone mass density in mandibles belonging to the two compared populations, determined by two quantitative radiomorphometric indices, is similar. Within the medieval population, there is an inverse correlation between the δ15N value and bone mass density. [ABSTRACT FROM AUTHOR]

The deformations and the corresponding configurations of the odd-mass Kr, Br, and Rb isotopes are investigated using the adiabatic and configuration-fixed constrained triaxial relativistic mean field theory. Several minima with prominent triaxial deformation and proper configuration are obtained in 75,77,79,81Kr, 75,77,79,81Br, and 75,79,81,83Rb nuclei, indicating the existence of chiral doublet bands. Based on the discussions about the involved orbitals in the chiral configurations, the possible coexistence of chiral and reflection based on the pseudospin orbitals in the 77,79,81Kr, 77,79Br, and 79,81Rb nuclei has been suggested. [ABSTRACT FROM AUTHOR]

Introduction: The Global Meteoric Water Line (GMWL) describes the linear relationship between stable hydrogen (δ 2H) and oxygen (δ 18O) isotopes in precipitation over large spatial scales and therefore represents a unique reference for water isotopic values. Although trees have the potential to capture the isotopic composition of precipitation, it remains unclear if the GMWL can be reconstructed from tree-ring stable isotopes, since δ 18O and δ 2H undergo in vivo physiological fractionation. Methods: We analyze the tree rings δ 18O and δ 2H values from six regions along a latitudinal gradient from Spain to Greenland. Results: The data show that the covariance between δ 18O and δ 2H closely follows the GMWL, which reflects the isotopic signature of large-scale precipitation patterns. We show that changes in regional tree-ring δ 18O and δ 2H values along wide latitudinal ranges are influenced by the isotopic composition of precipitation with temperature and latitude being the most significant drivers of spatial variation across the studied regions. In contrast, local tree-ring δ 18O and δ 2H values are mainly controlled by plant physiological fractionation processes that mask the isotopic signature of precipitation. Conclusion: We conclude that covariance in tree-ring δ 18O and δ 2H reflects the GMWL at larger spatial scales, but not when evaluating them at individual sites. [ABSTRACT FROM AUTHOR]

High-frequency precipitation (solid/liquid) isotope datasets are useful for identification of moisture sources and various dynamical and thermodynamical processes controlling precipitation formation. Here, we report three-year (2019–2021) daily rain isotope (both oxygen, δ18O hereafter, and hydrogen, δ2H, hereafter) datasets from three unique locations in India during the Indian Summer Monsoon (ISM). The locations are- (1) Port Blair- an island situated in the Bay of Bengal (BoB); (2) Mahabaleshwar, located at the crest of the Western Ghats Mountain; and (3) Tezpur, in northeast India, situated close to a dense forest. These stations receive moisture from different sources and experience different rain mechanisms during ISM. Therefore, the isotope datasets presented here would be useful for envisaging the impact of diverse rain formation processes on isotope values during the ISM. [ABSTRACT FROM AUTHOR]

An improved formula including shell closure effects is proposed to investigate α-decay half-lives. The coefficients of the improved formula are obtained by fitting the experimental α-decay half-lives of 677 nuclei with 62≤Z≤118. The root mean square deviation between α-decay half-lives calculated by the improved formula and experimental data is reduced from 0.435 to 0.385. The result indicates that the improved formula considering the shell closure effects is reliable in reproducing the experimental α-decay half-lives. In addition, the improved formula is extended to predict α-decay half-lives of nuclei with Z=119, 120 isotopes. The results of the predicted α-decay half-lives indicate that N=184 appears to be the next magic number beyond N=126. [ABSTRACT FROM AUTHOR]

Methane, a greenhouse gas and energy source, is commonly studied using stable isotope signals as proxies for its formation processes. In subsurface environments, methane often exhibits equilibrium isotopic signals, but the equilibration process has never been demonstrated in the laboratory. We cocultured a hydrogenotrophic methanogen with an H2-producing bacterium under conditions (55°C, 10 megapascals) simulating a methane-bearing subsurface. This resulted in near-complete reversibility of methanogenesis, leading to equilibria for both hydrogen and carbon isotopes. The methanogen not only equilibrated kinetic isotope signals of initially produced methane but also modified the isotope signals of amended thermogenic methane. These findings suggest that hydrogenotrophic methanogenesis can overwrite the isotope signals of subsurface methane, distorting proxies for its origin and formation temperature-insights crucial for natural gas exploration. [ABSTRACT FROM AUTHOR]

In this paper, we model the fission process by assuming that at certain elongation, after crossing the fission barrier, a fissile nucleus can be treated as a superposition of dinuclear systems (DNS). The distribution of primary fission fragments is described as a result of competition between evolution of initially formed DNS and its decay in relative distance. The level densities required for the calculations were microscopically derived accounting for deformation and excitation energy effects. The calculations performed for even 244−260Fm isotopes give overall good description of mass and neutron multiplicity distributions. To describe sudden onset of symmetric fission in 258Fm, the fissile nucleus is treated as superposition of DNS at smaller elongations than for lighter Fm isotopes, which is in line with significant reduction of half-life for 258Fm. Our results indicate the presence of bimodality due to coexistence of spherical and deformed mass symmetric fission modes. [ABSTRACT FROM AUTHOR]

The oceanic chromium (Cr) cycle is mainly governed by the interconversion and the distribution of Cr(VI) and Cr(III) species and their stable isotopic ratios (δ53Cr) in the water column. As a result, the Cr cycle generates a strong correlation between the natural logarithm of its dissolved concentration and δ53Cr regardless of the location of sampling. A few studies have reported the Cr composition of certain regions falling off the global Cr array, highlighting the local prevalence of underlying mechanisms participating in the Cr cycle in the oceans. In an effort to better constrain the global Cr array, this study presents an extensive dataset for total dissolved Cr concentration ([Cr] T) and δ53Cr in the Arctic Ocean in regions meeting the environmental conditions where Cr was observed to fall off the global Cr array (e.g. continental shelves, restricted water circulation, sea ice melting). We find that more than 70% of the Arctic seawater collected plot below the global Cr array due to a small addition of highly fractionated Cr (−2.8 ‰ to −1.1 ‰) and its transport across all the Arctic regions sampled. We identify the Chukchi Shelf as the region where highly fractionated Cr is produced, from where a Cr shuttle could work in tandem with the Arctic Fe and Mn shuttles to explain the production and widespread export of isotopically light Cr in the Arctic waters. We identify a second non-reductive release of highly fractionated Cr in the Canadian Arctic Archipelago, Baffin Bay and potentially the Labrador Sea via sediment resuspension, alongside addition of isotopically light Cr originating from crustal rocks. These findings demonstrate that the Arctic-modified outflow signature of Cr isotopes modify the Cr isotopic signature of the North Atlantic waters, and that the North Atlantic waters may deviate from the global Cr array depending on whether the isotopically light Cr added to the Arctic Ocean is Cr(III) that has not been scavenged or Cr(III) that has oxidized to Cr(VI). [ABSTRACT FROM AUTHOR]

ABSTRACT Background Aim Methods Results Conclusions Main transformation pathways of low molecular weight organic substances (LMWOS) are understood, but only limited knowledge exists on their transformations in different soils and on their interactions with biochar.Objectives were to study short‐term pathways of 13C‐labelled LMWOS with different functional groups in the presence and absence of biochar in arable loess soils.Soils from three sites were incubated with or without artificially aged biochar and 13C‐labelled acetate, alanine or glucose at different rates (10 or 50 µmol C g−1 soil) at 60% water holding capacity and 15°C for 5 days, and total and substrate‐derived CO2‐C and microbial biomass C (MBC) were determined and analyses of variance were calculated.Cumulative CO2‐C (ΣCO2‐C) emission was significantly (p ≤ 0.05) affected by substrate rate and type and their interaction. Biochar significantly stimulated total, but not substrate‐derived ΣCO2‐C (ΣCO2‐CSD) emission. Box‐Cox transformed MBC was significantly affected by site, substrate rate and type, whereas biochar had no significant effect. Substrate‐derived MBC (MBCSD) and carbon use efficiency (CUE) were significantly affected by site, substrate rate and type and their interaction.MBCSD and CUE results at low addition rate confirmed the greater importance of glucose for the build‐up of MBC compared to acetate and alanine, whereas the latter were mineralized to a greater extent. Biochar, once it is aged, which is the typical biochar form in soil, did not significantly affect build‐up of MBCSD and CUE and only slightly increased total, but not ΣCO2‐CSD emission. [ABSTRACT FROM AUTHOR]

Two diterpene synthases from the bacterium Chitinophaga pinensis were characterised. The first enzyme mainly produced the rearranged diterpene palmatol, a compound known from octocorals, while the second enzyme made the new coral‐type eunicellane chitinol. The mechanisms of both enzymes were deeply studied through isotopic labelling experiments, DFT calculations, and with a substrate analog containing a saturated double bond, resulting in the formation of derailment products that gave additional insights into the nature of the cyclisation cascade intermediates. The formation of coral‐type diterpenes poses interesting questions on the functions of these compounds in organisms as different as bacteria and corals. [ABSTRACT FROM AUTHOR]

A Central European catchment underlain by base-poor orthogneiss was studied using mass budgets and Mg–Ca–Sr isotope systematics. For 50 years, the catchment received large amounts of partly soluble dust from a nearby cluster of coal-burning power plants, while suffering from acid rain and severe spruce die-back. Our objective was to investigate to what extent anthropogenic dust contributes to Mg and Ca in runoff and to identify fractionations affecting Mg and Ca isotope composition of 13 ecosystem pools and fluxes. We hypothesized that if Mg and Ca runoff fluxes were significantly larger than their atmospheric inputs, Mg and Ca isotope ratios in runoff would converge to those of bedrock Mg and Ca. This relationship could be obscured by isotope fractionations. Strontium characterized by negligible isotope fractionations served as a Ca proxy. There was a strong positive correlation between Mg and Ca fluxes via spruce throughfall and catchment runoff. Monitoring of rainfall, canopy throughfall and runoff fluxes revealed a 20-, 15- and 15-fold excess of Mg, Ca and Sr in runoff, respectively, compared to atmospheric deposition fluxes. This sizeable excess per se would indicate predominance of geogenic base cations in runoff. The behavior of Mg and Ca isotopes was de-coupled. Petrographic study indicated that 92% of bedrock Mg was bound to easily dissolving biotite, 97% Ca was present in plagioclase, and nearly all Sr was in orthoclase. While Mg isotope ratios in bedrock and runoff were indistinguishable, corroborating predominantly geogenic Mg in runoff, Ca and Sr isotope ratios in bedrock and runoff were significantly different, consistent with a non-negligible contribution of atmospheric Ca and Sr to runoff. Previous study of sites underlain by felsic rocks indicated that the δ44Ca value of apatite was often higher than the δ44Ca value of plagioclase. Should weathering of apatite and/or plagioclase preferentially release Ca that is isotopically heavier than bulk rock, the geogenic Ca source at JEZ would converge to the mean δ44Ca value of runoff. Calcium isotope data would then become more consistent with a major role of geogenic Ca in JEZ runoff indicated by mass balance data. [ABSTRACT FROM AUTHOR]

The rubidium (Rb) isotope system has the potential to trace planetary evolution, magmatic‐fluid interaction and chemical weathering. These applications are based on Rb isotope measurement results with precisions fit for purpose, but measurements of low‐Rb geological materials are challenging due to large sample consumption and overload of ion‐exchange resin. Here we developed a measurement procedure for Rb isotope data (δ87RbSRM984) of low‐Rb geological materials using MC‐ICP‐MS. Using an Aridus III desolvator and Ni standard sampler + Ni X skimmer cone combination, the Rb loading amount was reduced significantly to 20 ng. A comparison between two methods for instrumental mass‐bias correction, the sample‐standard bracketing and combined sample‐standard bracketing and internal (Zr) normalisation (C‐SSBIN), shows that C‐SSBIN could produce Rb isotope data with better intermediate measurement precisions but strictly restricted to optimal Zr/Rb ratio. The robustness of this method was demonstrated by monitoring δ87RbSRM984 data of two in‐house Rb isotope standards, replicates, some reference materials with δ87RbSRM984 values previously reported, and element‐doped and matrix‐spiked synthetic solutions. Based on repeated measurements of Rb isotope standards and reference materials, the long‐term (over one year) intermediate precision was better than 0.05‰ (2s, standard deviations). We additionally recommend thirteen reliable reference materials for future Rb isotope ratio measurements. [ABSTRACT FROM AUTHOR]

U–Th–Pb (LA-ICP-MS) geochronological studies of detrital zircon from the Quaternary deposits of the western part of the Ufaley block (Middle Urals) were performed. The studied area was a tectonic fragment composed of an amphibolite–gneiss complex containing bodies of Precambrian clinopyroxenites. The pronounced age maximum corresponds to the age interval of 2100–2000 Ma, and several small peaks correspond to the interval of 3200–2500 Ma. All this gives us a good reason to believe that Early Precambrian rocks, which have not been identified before, are present within the Ufaley block. [ABSTRACT FROM AUTHOR]

In addition to solar-neutrino fluxes, the Borexino detector is able to record antineutrino fluxes by employing reactions of elastic neutrino- and antineutrino-electron scattering. Antineutrino fluxes are produced within the Earth by natural-radioactivity isotopes and at the Earth's surface by nuclear reactors of nuclear power plants. The most recent data accumulated by the Borexino detector are analyzed upon adding known antineutrino fluxes to the backgrounds and fluxes of solar neutrinos. This analysis made it possible to determine the flux of K antineutrinos, which turned out to be quite significant in magnitude. At the same time, all fluxes of solar neutrinos are compatible with the low-metallicity model of the Sun. [ABSTRACT FROM AUTHOR]

The internal detector background arising in searches for neutrinoless double-beta decay of the isotope Nd from the two-neutrino beta decay of the same isotope is calculated. The calculation is performed for a detector several liter in volume based on a neodymium-doped liquid organic scintillator and implemented in various configurations and at various neodymium concentrations of up to 5.5 g/l. Limits on the detector sensitivity in searches for neutrinoless double-beta decay of the isotope Nd are obtained. [ABSTRACT FROM AUTHOR]

Contamination of water resources by leachates emanating from different types of landfills and waste heaps is a serious concern. Proper management is possible, only after source identification. Statistical methods such as principal component analysis, Pearson correlation coefficients and Hierarchical cluster analysis can indicate the sources of pollutants, but the quantification of contributions from each of the sources is not possible. Thus tracing the movement of leachate plumes through environmental isotopes (stable and radioactive) is gaining importance. Though the application of isotopes for source identification is an accepted practice, the types and sources of pollution can be traced, and the various advantages and disadvantages associated with the choice of isotopes are not well documented. Thus the review first attempts to understand the possible use of conventional and potential isotopes under different waste composition and try to summarize the isotopic signature of isotopes in different sources and their variability to understand their applicability as a tracer of pollution plume. This study shows that the applicability of δ13CDIC as a tracer is limited to subsurface environment. Further, nitrogen isotopes δ15N-NH4 and δ15N-NO3 carry the signature of shallow aquifer and thus cannot be applied as tracer for shallow aquifer. Isotopes of Boron, Strontium, Tritium, Lead, Deuterium, Sulphur, Lithium and Cadmium are useful in tracing the leachate plume movement both in surface and groundwater. The applicability of Boron, Sulphur and Lithium are limited by adsorption. Strontium, Tritium, Lead and Cadmium show very low fractionation and thus become potential candidate to be used as tracers. [ABSTRACT FROM AUTHOR]

The origin of highly-fractionated granite-pegmatite systems and their associated rare metal mineralization has been widely studied, but there is still ongoing debate. Prevailing hypotheses suggest that pegmatite formation and the associated rare metal mineralization are closely related to aqueous fluid processes. Lithium (Li) isotope analysis has been widely applied to trace granite-pegmatite evolution. This is because lithium is widely present in various minerals (e.g., mica, tourmaline) that record the melt and fluid compositions, and lithium isotopes are sensitive to magmatic-hydrothermal processes. We briefly review the methodology of Li isotope analyses, the mechanisms of Li isotopic fractionation, and, in particular, Li isotope fractionation in granite-pegmatite system based on Li isotope data we have collected and the latest developments in Li isotope geochemistry. With the development of analytical technology, high-precision measurement of the Li content and isotopic compositions have facilitated a series of scientific breakthroughs in understanding the magmatic-hydrothermal evolution of rare-element ore deposits. Li isotope analyses on bulk mineral separates have demonstrated their ability to trace various hydrothermal processes. In situ Li isotope analysis methods has been enhanced by the development of new, homogeneous mineral reference materials. In situ SIMS and LA-MC-ICP-MS Li isotope measurements on minerals (e. g., tourmaline) will likely become more important in studying the fluid-rock interactions in magmatic, metamorphic, and hydrothermal processes, as well as on pegmatite petrogenesis and rare-metal mineralization. [ABSTRACT FROM AUTHOR]

Precipitation stable-isotope data are often used in hydroclimatic, hydrological and hydrogeological investigations, with measurements typically undertaken on integrated monthly samples. However, daily sampling reveals overlooked aspects of controls on precipitation isotope values, including synoptic meteorological conditions. We present a one-year record of stable isotopes in daily precipitation during 2021, from a site in SE England close to Greater London. We find marked daily variability over the course of the year (–15.62 to +0.92 ‰ for δ18O, –108.7 to +2.9 ‰ for δ2H and –6.5 to +23.1 ‰ for deuterium excess). Correlations with individual meteorological variables including precipitation amount, temperature and weather type are moderate to weak suggesting complex controls on the daily rainfall isotope values. The daily data are compared with three other daily datasets from England and, by conversion to monthly values, directly with data from three long-term collection stations across Britain and Ireland. The scale of variability in the daily data from our site is consistent with that seen in other English records despite them all coming from different time periods. The monthly data show broad consistency, although there are differences that also highlight geographical variability in precipitation values across the British Isles. [ABSTRACT FROM AUTHOR]

Cisco (Coregonus artedi) are a widespread, cold‐water zooplanktivore native to North America. Although Cisco are generally referred to as an "obligate zooplanktivore," there is some evidence that the species exhibits considerable variability in trophic niche. Here, we assessed how Cisco body size relates to trophic position, that is, trophic ontogeny. We analysed 13C and 15N isotopes from Cisco ranging from 127 to 271 mm in body length (n = 66) from Trout Lake, Vilas County, Wisconsin, USA. 15N isotopes showed smaller Cisco had a trophic position of ~3, which steadily increased to ~3.5 for larger Cisco. Further, 13C isotope signatures showed Cisco transitioned to be more pelagically reliant (lower 13C signatures). Using gillnet catch data, we found that larger Cisco were using deeper habitats than smaller Cisco. Our results support that Cisco have significant variability in trophic niche even though they are traditionally thought of as an obligate planktivore. Overall, we emphasize that researchers should be cautious when generalizing Cisco trophic function, particularly when considering the broader food web. [ABSTRACT FROM AUTHOR]

Antimony‐119 (119Sb) holds promise for radiopharmaceutical therapy (RPT), emitting short‐range Auger and conversion electrons that can deliver cytotoxic radiation on a cellular level. While it has high promise theoretically, experimental validation is necessary for 119Sb in vivo applications. Current 119Sb production and separation methods face robustness and compatibility challenges in radiopharmaceutical synthesis. Limited progress in chelator development hampers targeted experiments with 119Sb. This review compiles literature on the toxicological, biodistribution and redox properties of Sb, along with existing Sb complexes, evaluating their suitability for radiopharmaceuticals. Sb(III) is suggested as the preferred oxidation state for radiopharmaceutical elaboration due to its stability in vivo and lack of skeletal uptake. While Sb complexes with both hard and soft donor atoms can be achieved, Sb thiol complexes offer enhanced stability and compatibility with the desired Sb(III) oxidation state. For 119Sb to find application in RPT, scientists need to make discoveries and advancements in the areas of isotope production, and radiometal chelation. This review aims to guide future research towards harnessing the therapeutic potential of 119Sb in RPT. [ABSTRACT FROM AUTHOR]

The purpose of the scientific cruise CEAMARC was to explore the East-Antarctic sector, off Georges V and Terre Adélie, to study the biodiversity of plankton, fishes and benthic fauna. The aim of the current study is to focus on a major part of this benthic fauna, highlighting the representatives of the phylum Brachiopoda. Still present in all oceans, brachiopods, suspension feeders, are not often studied. They are marine invertebrates with a calcite bivalved shell, living attached to various substrates by means of their pedicle or by cementation. The purpose of this study was to review their diversity compared to the equivalent representatives, when available, in circumpolar and/or subantarctic waters, the characteristics of the species and the micro and nanostructure of their shells (biomaterial). The ecology and depth ranges are reported. As well, the results of multiproxy assessment of the brachiopod calcite shell highlight the role these organisms play in reflecting the environmental conditions of the surrounding seawater. As highlighted in a recent study on modern shells, including some subaustral and Austral species, geochemical thermometers like carbonate clumped isotopes (Δ47), independent from δ18Osw values, were used. [ABSTRACT FROM AUTHOR]

161Tb is a high-potential emerging radionuclide in targeted radionuclide therapy due to the high emission of Auger electrons. So, efforts to obtain 161Tb have begun in Iran. To obtain NCA 161Tb, the development of an effective Gd/Tb separation approach is necessary. In this case, an Ln-resin column was used to separate Tb from the Gd/Tb matrix using the extraction chromatography technique. The results demonstrated that the optimal separation conditions were achieved by separating gadolinium and terbium isotopes using 0.8 and 3N HNO3 solutions, respectively. The final 161Tb radionuclide has obtained 81% separation yield, more than 99% radionuclide purity, and 99% radiochemical purity. [ABSTRACT FROM AUTHOR]

Since the 135Cs and 137Cs concentration level of environmental soil in prefectures adjacent to Fukushima is low at about 5.5 × 10−15 − 6 × 10−13 g g−1, a large amount of soil is required to obtain sufficient amount to measure them precisely. Two Cs separation methods which allow to treat large amounts of leached soil solution were developed: 1) A continuous butch extraction method using calix[4]arene-bis(t-octylbenzo-crown-6) and 2) A combination method of selective Cs adsorption using ammonium phosphotangstate and anion-cation exchange resins. These methods were applied to low Cs concentration samples, and good precision of 0.8–2.1% in the measurement of 135Cs/137Cs isotope ratio was obtained. [ABSTRACT FROM AUTHOR]

Neutron irradiation of gold foils in H2O causes the release of 198Au into the liquid in measurable quantities. Experiments prove that irradiation of the foils in water indeed yields 10 times more activity in the liquid than when the foil is removed from the liquid before irradiation. The activity of the gold foil shows no correlation with the yield of ejected 198Au ions, but the duration of neutron irradiation does. However, not all experiments are fully conclusive as no linearity between irradiation duration and emitted 198Au is apparent. A speciation experiment by crystallization reveals that the nuclear reaction produces 198Au3+ ions quantitatively. [ABSTRACT FROM AUTHOR]