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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.

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]

Current models of early human subsistence economies suggest a focus on large mammal hunting. To evaluate this hypothesis, we examine human bone stable isotope chemistry of 24 individuals from the early Holocene sites of Wilamaya Patjxa (9.0-8.7 cal. ka) and Soro Mikaya Patjxa (8.0-6.5 cal. ka) located at 3800 meters above sea level on the Andean Altiplano, Peru. Contrary to expectation, Bayesian mixing models based on the isotope chemistry reveal that plants dominated the diet, comprising 70-95% of the average diet. Paleoethnobotanical data further show that tubers may have been the most prominent subsistence resource. These findings update our understanding of earliest forager economies and the pathway to agricultural economies in the Andean highlands. The findings furthermore suggest that the initial subsistence economies of early human populations adapting to new landscapes may have been more plant oriented than current models suggest.

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]

We report high resolution measurements of the stable water isotope ratios (δ18O, δD) from the Mount Brown South ice core (MBS, 69.11° S 86.31° E). The record covers the period 873 - 2009 CE with sub-annual temporal resolution. Preliminary analyses of surface cores have shown the Mount Brown South site has relatively high annual snowfall accumulation (0.3 metres ice equivalent) with a seasonal bias toward lower snowfall during austral summer. Precipitation at the site is frequently related to intense, short term synoptic scale events from the mid-latitudes of the southern Indian Ocean. Higher snowfall regimes are associated with easterly winds, while lower snowfall regimes are associated with south-easterly winds. Isotope ratios are measured with Infra-Red Cavity Ring Down Spectroscopy, calibrated on the VSMOW/SLAP scale and reported on the MBS2023 time scale interpolated accordingly. We provide estimates for measurement precision and internal accuracy for δ18O and δD. [ABSTRACT FROM AUTHOR]

The biosynthesis of six recently reported non‐canonical C16 sesquiterpenoids named after ancient Greek philosophers, archimedene, aristotelene, eratosthenene, pythagorene, α‐democritene and anaximandrene, was investigated through density functional theory (DFT) calculations and isotopic labeling experiments. The results revealed for all compounds except archimedene a unique fragmentation‐recombination mechanism as previously demonstrated for sodorifen biosynthesis, in addition to a remarkable "dancing" mechanism for anaximandrene biosynthesis. [ABSTRACT FROM AUTHOR]

Summary Contradictory evidence exists regarding the relevance of Péclet‐like gradients in leaf water isotopes, making it difficult to accurately predict variation in isotope composition. Here, we use H218O vapour labelling to directly test whether leaf water isotopes diffuse back into the xylem to be carried forward to more distal leaf portions. Backward diffusion has been assumed, due to observations of increasing enrichment towards the tip and outer edges of some leaves. Further complicating the selection of leaf water isotope models is the observation that some, but not all, leaves demonstrate a radial Péclet effect in bulk leaf water and that the hydraulic design of leaves may influence the development of isotope gradients in leaves. Carry‐forward of H218O vapour label was detected in the two monocot species assessed (oat and corn), but not in the two dicot species (foxglove and sunflower). Further, bulk leaf water measurements at differing transpiration rates indicated that a bulk leaf water Péclet effect was relevant for foxglove only. We conclude that both leaf hydraulic design and relative velocities of water within transport pathways influence leaf water isotope composition, reconciling seemingly contradictory previous results regarding the relevance of Péclet effects to leaf water isotopes. [ABSTRACT FROM AUTHOR]

Freshwater mussels preserve valuable information about hydrology, climate, and population dynamics, but developing seasonal chronologies can be problematic. Using clumped isotope thermometry, we produced high-resolution reconstructions of modern and historic (~ 1900) temperatures and δ18Owater from mussel shells collected from an impounded river, the Brazos in Texas, before and after damming. We also performed high-resolution growth band analyses to investigate relationships between mussel growth rate, rainfall, and seasonal temperature. Reconstructed δ18Owater and temperature vary little between the modern (3R5) and historic shell (H3R). However, a positive relationship between reconstructed δ18Owater and growth rate in H3R indicates that aside from diminished growth in winter, precipitation and flow rate are the strongest controls on mussel growth in both modern and pre-dam times. Overall, our results demonstrate (1) the impact, both positive and negative, of environmental factors such as flow alteration and temperature on mussel growth and (2) the potential for clumped isotopes in freshwater mussels as a paleohydrology and paleoclimate proxies in terrestrial environments. [ABSTRACT FROM AUTHOR]

This review provides a summary of the existing literature on a crucial raw material for the production of isotopically pure semiconductors, which are essential for the development of second-generation quantum systems. Silicon-28-tetrafluoride (28SiF4) is used as an educt for several isotope-engineered chemicals, such as silane-28 (28SiH4) and silicon-28-trichloride (28SiHCl3), which are needed in the pursuit of various quantum technologies. We are exploring the entire chain from the synthesis of 28SiF4 to quantum applications. This includes the chemical properties of SiF4, isotopic enrichment, conversion to silanes, conversion to bulk 28Si and thin films, the physical properties of 28Si (spin neutrality, thermal conductivity, optical properties), and the applications in quantum computing, photonics, and quantum sensing techniques. [ABSTRACT FROM AUTHOR]

Purpose: Iron absorption in sickle cell anemia (SCA) remains unclear and studies in adults with SCA are scarce. The aim of this study was to evaluate the iron absorption SCA adults and its association with iron status and hepcidin concentration. Methods: SCA patients (n = 13; SCAtotal) and control participants (n = 10) ingested an oral stable iron isotope (57Fe). Iron absorption was measured by inductively coupled plasma mass spectrometry (ICP-MS) 14 days after isotope administration. Patients with ≥ 1000 ng/mL serum ferritin were considered to present iron overload (IO) (SCAio+; n = 3) and others classified without IO (SCAio-; n = 10). Results: Iron absorption in the control group ranged from 0.3 to 26.5% (median = 0.9%), while it varied from 0.3 to 5.4% in SCAio+ (median = 0.5%) and from 0.3 to 64.2% in the SCAio- (median = 6.9%). Hepcidin median values were 14.1 ng/mL (3.0–31.9 ng/mL) in SCAio-, 6.2 ng/mL (3.3–7.8 ng/mL) in SCAio + and 6.2 ng/mL (0.6–9.3 ng/mL) in control. Iron absorption was associated with ferritin level (r = − 0.641; p = 0.018) and liver iron concentration (LIC; r = − 0.786; p = 0.036) in the SCAtotal group. Conclusion: Our data suggest that SCAio- individuals may be at risk of developing primary IO. Simultaneously, secondary IO may induce physiological adaptation, resulting in reduced iron absorption. Further studies evaluating intestinal iron absorption using larger sample sizes should be conducted to help establish a safe nutrition approach to be adopted and to ensure the security of food-fortifying public policies for these patients. Trial registration: This trial was registered at www.ensaiosclinicos.gov.br (Identifier RBR-4b7v8pt). [ABSTRACT FROM AUTHOR]

The study of the static properties of isotopes, such as ground-state energy of the system and the energy spectra, electric quadrupole, as well as charge radii and so many others, is one of the significant areas of interest in nuclear physics. Therefore, in this field, the ground-state energy of a nucleus is an essential part of the study. In addition, understanding the nuclear force depends critically on understanding the nuclear charge radii. In this work, we considered Li isotopes in the study of two-body system configuration, and then we calculated the ground-state energy and charge radii for some of them. [ABSTRACT FROM AUTHOR]

On the White Sea islands and coast of North Karelia, in the Chupa sector of the Belomorian mobile belt (BMB), carbonate–silicate and quartz veins are localized in bodies of Early Proterozoic metabasites and their contacts with host gneisses. The isotopic characteristics of coarse crystal vein carbonates (δ18O and δ13C), as well as associated quartz (δ18O) and biotite (δ18O and δD), were studied. The isotopic composition of oxygen suggests biotite–quartz–carbonate equilibria during the formation of veins at temperatures of 520–450°C. The O and H isotopic characteristics of biotite correspond to the equilibrium of the fluid with metamorphic rocks. At the same time, the isotopic compositions of O and C carbonates indicate different CO2 sources in fluids. There are three groups of carbonates according to δ18О and δ13С. The first group shows "magmatic" isotopic characteristics of the CO2 source (δ18ОVSMOW = 7.1...12.1‰; δ13СVPDB = –6.3...–4.5‰). Carbonates of the second group have high δ18О and δ13С, characteristic of Precambrian sedimentary carbonates (δ18ОVSMOW = 21.9...24.7‰; δ13СVPDB = –2.2...–2‰), similar to those described earlier in the neighboring Engozero sector of the BMB. In the third group, the δ13С values are similar to the carbonates of the first group, and δ18О, to the second group (δ13СVPDB = –1.7...0.9‰, δ18ОVSMOW = 6...12‰). The O and C isotopic compositions of carbonates of the third group can be obtained from the action of a putative magmatic fluid on both the primary sedimentary source of metamorphic fluids and redeposited vein carbonates. [ABSTRACT FROM AUTHOR]

In recent decades, the Eurasian native and invasive gastropod Radix auricularia has been found widely dispersed in the endemic communities of Lake Baikal. A comparative analysis of stable carbon (δ13C) and nitrogen (δ15N) isotopes in the foot tissues of individuals of this species and endemics with similar shell sizes, filter-feeding Parabaikalia florii (Baicaliidae) and grazer-scraper Benedictia baicalensis (Benedictiidae), was carried out to identify possible competition for food resources between the three coexisting species. Despite the similarity of the δ15N values (P = 0.37), R. auricularia and P. florii have non-overlapping isotopic niches (P = 0.001), assimilating different components of phytonutrients. Radix auricularia and B. baicalensis differed in the δ15N values (P = 0.001) with a significant overlap of the isotopic niches (P = 0.66) due to the ability of the latter to consume food of animal origin. We additionally discuss the disparities and similarities of the basic components in the food boluses of the alien and endemic species. [ABSTRACT FROM AUTHOR]

Zealandia has very few biostratigraphic markers to help elucidate the often complex and discontinuously cored stratigraphy of Quaternary sequences on the margins and submarine plateaux of the subcontinent. In this study, a detailed biostratigraphic framework has been developed to help unravel the complex stratigraphy of tectonically deformed Quaternary sediments on the Hikurangi margin of north-eastern Zealandia. The framework is based on well documented and dated 0–1.2 Ma planktic foraminiferal records from Ocean Drilling Project (ODP) Site 181–1123 on the Chatham Rise, just north of the Subtropical Frontal Zone. The framework has 104 biostratigraphic markers and is subdivided using the Sinistral Truncorotalia truncatulinoides Zone (STZ) 0–533 ka, the Dextral Tr. truncatulinoides Zone (DTZ) 533–2440 ka, the lowest common occurrence (LCO) Tr. truncatulinoides (621 ka), the highest common occurrence (HCO) Neogloboquadrina pachyderma (624 ka), and the HCO Tr. crassacarina (1101 ka). Further subdivision is then based on the tops and bases of short-lived climatically-tempered influxes of Globigerinoides ruber, Hirsutella hirsuta, Hr. praehirsuta, Tr. truncatulinoides, Tr. crassacarina, and Nq. pachyderma. Most of these biostratigraphic markers are not unique, but sequences of markers that are unique to each marine isotope stage provide an unprecedented level of biostratigraphic detail and chronological dating when they are used within the contextual chronological framework of keystone biostratigraphic markers. [ABSTRACT FROM AUTHOR]

The geological and environmental applications of tin (Sn) isotopes have been hindered by the shortcomings of chemical purification, as severe loss of Sn would occur during sample preparation (evaporation and re-dissolution) and column separation, triggering isotope measurement bias. In this study, we develop a novel and robust separation method to purify Sn from natural samples for accurate isotope measurements. The protocol is established by combining two chromatographic columns loaded with AG 1-X8 and AG 50W-X12 resins, and optimizing the sample evaporation and re-dissolution procedures. The method is proven to efficiently eliminate the main interferents such as Ag, Zn, Mo, Cd and Sb and results in low procedural blank (0.54 ± 0.21 ng, n = 3), quantitative recovery (95--102%, n = 32) and good external precision (δ120Sn of 0.02--0.04‰, in 55 measurements) for isotope measurement. The protocol is further applied to seven geological and environmental reference materials (BCR-2, BHVO-2, AGV-2, JG-2, AC-E, PACs-2 and GSS 7) and new values are reported for both odd (δ119Sn and δ117Sn) and even (δ120Sn and δ122Sn) Sn isotope ratios. This study demonstrates clearly the potential application of our method for studying the geochemical behaviors of Sn and its isotopes in various aspects. [ABSTRACT FROM AUTHOR]

The study is aimed to determine the C13 and O18 isotope ratios of plant species belonging to different life forms in different forest types in Yenice Forests hot spot. Carbon and oxygen isotope ratios are important in providing long-term information about plants. In our study, we grouped the plants by considering the life forms of Raunkiaer. We determined the C13 and O18 isotope ratios of life forms in different forest layers. We found highly positive correlations (p<0.05) between δ13C and δ18O isotope ratios in beech-fir and pure oak forest habitats. In the Yenice Forests, which have a megathermal climate type, plants in different forest layers have settled in the areas by choosing the life forms where water will be used most effectively. Geophyte (-27.38±2.27 p<0.05) is the life form with the highest C13 isotope ratio in terms of life forms. This situation proves that the group that felt the water deficiency the earliest is the geophyte form. For O18 isotope ratio, therophytes using surface water are the highest (24.06±3.92 p<0.05) life forms. It is important to examine the water deficiency in old forests such as Yenice Forests through life forms. [ABSTRACT FROM AUTHOR]

Mountainous zones are often characterized by complex orography and contacts between different aquifers that usually complicate the use of isotope hydrology techniques. The Apennine chain (Italy) and 10 mountain and mid‐mountain areas belonging to it are the objective of this study. An original isotopic data treatment, able to identify the most probable recharge area for several springs/springs' groups/wells, has been developed. The method consists of a two‐step approach: (1) the determination of the spring/wells computed isotope recharge elevation; (2) an advanced δ18O precipitation distribution model over the study area supported by statistical and GIS‐based procedures implemented by two processes: first, the clipping of precipitation δ18O values (depicted from the δ18O–elevation relationships obtained for each study area) over a most probable recharge area for each analyzed spring or well and, second, the calculation of the overlapping distribution between the spring/well mean δ18O values ± σ and the precipitation δ18O content for each outcropping aquifer. A new regional δ18O gradient covering 150 km latitudinal length of central Italy has been defined. Seven LMWL and δ18O–elevation relationships able to represent the local precipitation isotopic composition have been obtained. The mean elevation of the springs and wells recharge areas have been assessed by a comparison between the obtained gradient with nine δ18O gradients available in the literature and those obtained at a local scale. The new isotopic modeling approach can stress whether the mere isotope modeling based on the stable isotope of oxygen agrees with the hydrogeological setting of the study areas. [ABSTRACT FROM AUTHOR]

The work reports a novel application of the interacting boson model in light-mass region around 48Ca, that takes into account intruder states and configuration mixing. The model is shown to provide a reasonable description of the observed low-lying yrast and yrare states of the N = 28 even–even isotones from Si to Fe, and even–even Ca isotopes. The nature of 0 2 + states is addressed in terms of the competition between spherical and deformed intruder configurations, and the rigidity of the N = 28 shell gap is tested, particularly for 44S. The 0 2 + isomer in 44S is shown to arise from a weak mixing between the two configurations and called as shape isomer. The unresolved low-lying spectra in 46Ar is also approached using the core-excitations across N = 28 shell. The SU(3) structure in 42Si is supported by the present calculation. The nearly spherical nature of 50Ti, 52Cr, 54Fe and 42,44,46Ca isotopes is found, while the core excitations are found to be essential for the description of yrare states. Shell model calculation is also performed for comparison. [ABSTRACT FROM AUTHOR]

In the last decade, cases of radioactive isotope theft have been observed more frequently in Mexico, endangering human health, biodiversity, and the environment due to the risks of mishandling radioactive isotopes. The aim of this study was to analyze the theft of radioactive isotopes in Mexico in the period 2011–2023 from the perspective of green criminology through official data and radiological emergency bulletins. The results show that the most frequently stolen isotopes were 192Ir, 137Cs, and 131I in this study period, and it was also identified that the isotopes are stolen unintentionally, since it is the vehicles that transport them that are stolen, most of the time without knowing what they contain. It is concluded that the theft of radioactive isotopes in Mexico is a crime linked to vehicle theft, which in turn stems from the conditions of public insecurity but puts the health, safety and well-being of people, biodiversity, and the country's ecosystems at risk, so that institutional actions must be oriented considering the conditions of public insecurity to improve nuclear safety in the country. [ABSTRACT FROM AUTHOR]

Background/Objectives: Sickle cell anemia (SCA) is marked by hypoxia, inflammation, and secondary iron overload (IO), which potentially modulate hepcidin, the pivotal hormone governing iron homeostasis. The aim was to evaluate the iron incorporation in red blood cells (RBC) in SCA pediatric patients, considering the presence or absence of IO. Subjects/Methods: SCA children (n = 12; SCAtotal) ingested an oral stable iron isotope (57Fe) and iron incorporation in RBC was measured after 14 days. Patients with ≥1000 ng/mL serum ferritin were considered to present IO (SCAio+; n = 4) while the others were classified as being without IO (SCAio−; n = 8). Liver iron concentration (LIC) was determined by Magnetic Resonance Imaging (MRI) T2* method. Results: The SCAio+ group had lower iron incorporation (mean ± SD: 0.166 ± 0.04 mg; 3.33 ± 0.757%) than SCAio− patients (0.746 ± 0.303 mg; 14.9 ± 6.05%) (p = 0.024). Hepcidin was not different between groups. Iron incorporation was inversely associated with serum ferritin level (SCAtotal group: r = −0.775, p = 0.041; SCAio− group: r = −0.982; p = 0.018) and sickle hemoglobin (HbS) presented positive correlation with iron incorporation (r = 0.991; p = 0.009) in SCAio− group. LIC was positively associated with ferritin (SCAtotal: r = 0.921; p = 0.026) and C reactive protein (SCAio+: r = 0.999; p = 0.020). Conclusion: SCAio+ group had lower iron incorporation in RBC than SCAio− group, suggesting that they may not need to reduce their intake of iron-rich food, as usually recommended. Conversely, a high percentage of HbS may indirectly exacerbate hypoxia and seems to increase iron incorporation in RBC. Trial Registration: This trial was registered at www.ensaiosclinicos.gov.br. Identifier RBR-4b7v8pt. [ABSTRACT FROM AUTHOR]

Rationale: Signal detection for uranium–lead (U–Pb) dating of zircon is typically performed via ion counters. Here, we develop a preliminary understanding of the strengths and limitations of faraday‐cup‐based detection. Methods: A suite of zircon reference materials and the NIST‐610 glass were sampled using laser ablation followed by U–Pb isotope ratio measurement on a Neoma multicollector‐inductively coupled plasma‐mass spectrometer. Results: We were able to produce geologically accurate 207Pb/206Pb, 206Pb/238U, and 207Pb/235U ratios for the NIST‐610 glass and the zircon standards, with ages ranging from ~2.5 Ga to ~337 Ma (TanBrown A, Oracle, 91550, Mud Tank, Temora, and Plešovice). Two of the younger zircon standards examined (94‐35, ~55.6 Ma, and Fish Canyon, 28.6 Ma) yielded accurate 206Pb/238U but not 207Pb/235U or 207Pb/206Pb ratios, whereas the youngest zircon standard (Penglai, ~4.4 Ma) failed for all three ratios of interest. The accuracy and precision of the all‐faraday method are directly tied to signal intensity, with reliable data capable of being produced even when both isotopes in a ratio have signals below ~0.001 V (equivalent to ~62 500 cps on an ion counter). Conclusion: The all‐faraday cup multicollection method provides sufficient sensitivity to obtain geologically meaningful U–Pb data, with possible advantages being that laser pit depth‐dependent changes in the observed interelemental fractionation behavior may be easier to correct using a static collector configuration compared to when the ion beam is swept across a single detector while also removing the need for an interdetector‐type calibration. Further work is needed to refine the all‐faraday cup method (e.g., application of background subtraction and common Pb corrections, outlier removal, and interelement as well as down‐hole fractionation corrections), but our initial results demonstrate that the faraday detector method has sufficient sensitivity to warrant further study. [ABSTRACT FROM AUTHOR]

Coral reefs rely heavily on reef fish for their health, yet overfishing has resulted in their decline, leading to an increase in fast-growing algae and changes in reef ecosystems, a phenomenon described as the phase-shift. A clearer understanding of the intricate interplay between herbivorous, their food, and their gut microbiomes could enhance reef health. This study examines the gut microbiome and isotopic markers (δ13C and δ15N) of four key nominally herbivorous reef fish species (Acanthurus chirurgus, Kyphosus sp., Scarus trispinosus, and Sparisoma axillare) in the Southwestern Atlantic's Abrolhos Reef systems. Approximately 16.8 million 16S rRNA sequences were produced for the four fish species, with an average of 317,047 ± 57,007 per species. Bacteria such as Proteobacteria, Firmicutes, and Cyanobacteria were prevalent in their microbiomes. These fish show unique microbiomes that result from co-diversification, diet, and restricted movement. Coral-associated bacteria (Endozoicomonas, Rhizobia, and Ruegeria) were found in abundance in the gut contents of the parrotfish species Sc. trispinosus and Sp. axillare. These parrotfishes could aid coral health by disseminating such beneficial bacteria across the reef. Meanwhile, Kyphosus sp. predominantly had Pirellulaceae and Rhodobacteraceae. Four fish species had a diet composed of turf components (filamentous Cyanobacteria) and brown algae (Dictyopteris). They also had similar isotopic niches, suggesting they shared food sources. A significant difference was observed between the isotopic signature of fish muscular gut tissue and gut contents, pointing to the role that host genetics and gut microbes play in differentiating fish tissues. [ABSTRACT FROM AUTHOR]

The coherent continental-wide speleothem water isotope records are accompanied by regionally inconsistent moisture patterns within the Asian summer monsoon (ASM) region, leaving a disputed explanation of monsoonal hydroclimate variability at the orbital timescale. Here, the transient simulation forced by orbital parameters during the past 300,000 years in an isotope-enabled fully coupled model shows that the complex ASM response can be understood as a grand dipole pattern of oxygen isotope and rainfall between South Asia and Japan, with South China lying in a hybrid transition region. While the dipole monsoon rainfall change between South Asia and Japan is related to the large-scale circulation adjustment in response to Northern Hemisphere summer insolation, the dipole oxygen isotope pattern is associated with the changing contribution of moisture sources. Our results provide new clues to reconcile ASM hydroclimate patterns at orbital timescale as revealed by the water isotope records and other hydrological proxies. [ABSTRACT FROM AUTHOR]

Understanding the key drivers controlling rainfall stable isotope variations in inland tropical regions remains a global challenge. We present novel high‐frequency isotope data (5–30 min intervals) to disentangle the evolution of six stratiform rainfall events (N = 112) during the passage of convective systems in inland Brazil (September 2019–June 2020). These systems produced stratiform rainfall of variable cloud features. Depleted stratiform events (δ18Oinitial ≤ −4.2‰ and δ18Omean ≤ −6.1‰) were characterized by cooler cloud‐top temperatures (≤−38°C), larger areas (≥48 km2), higher liquid‐ice ratios (≥3.1), and higher melting layer heights (≥3.8 km), compared to enriched stratiform events (δ18Oinitial ≥ −3.8‰ and δ18Omean ≥ −5.1‰). Cloud vertical structure variability was reflected in a wide range of δ18O temporal patterns and abrupt shifts in d‐excess. Our findings provide a new perspective to the ongoing debate about isotopic variability and the partitioning of rainfall types across the tropics. Plain Language Summary: Stable water isotopes were used to analyze the formation of stratiform rainfall in the inland tropics of Brazil. The growth of this type of precipitation is associated with continuous condensation‐deposition processes. High‐resolution isotopic variations were analyzed using meteorological information, including satellite products and vertical micro rain radar observations. Our results showed that for stratiform rainfall, clouds with higher temperatures are related to more heavy isotopes, while less heavy isotopes are more frequent for stratiform rainfall coming from colder clouds. Our findings provide a detailed framework to improve isotope enabled models skills to represent the isotopic composition for different cloud types based on observations. Key Points: Weather systems and cloud development modulate rainfall isotope depletionsCloud top temperature, rain area, and water content (liquid‐ice ratio) are key parameters to decipher tropical rainfall isotope variationsIsotopic variations during intra‐evens are controlled by cloud phases, rainfall vertical structure, and the height of the melting layer [ABSTRACT FROM AUTHOR]

The phenomenon of lithic miniaturization during the Late Pleistocene at times coincided with increased artifact standardization and cutting edge efficiency–likely reflecting the use of small, sharp artifacts as interchangeable inserts for composite cutting tools and hunting weapons. During Marine Isotope Stage 2, Upper Paleolithic toolmakers in northern East Asia specifically used pressure techniques to make small, highly standardized lithic artifacts called microblades. However, little is currently known about how microblades affected the cutting edge efficiency of the toolkits they were a part of. We applied three methods of analyzing cutting edge efficiency to two Upper Paleolithic assemblages recently excavated from Tolbor-17, Mongolia, that document the periods before and after the introduction of microblade technology to the Tolbor Valley. A model incorporating allometric relationships between blank cutting edge length and mass suggests no difference in efficiency between the two periods, while two more conventional approaches both indicate a significant increase. The potential for improved cutting edge efficiency is only observed when the microblade sample is artificially inflated via simulation. Our results highlight challenges related to detecting and interpreting archaeological differences in cutting edge efficiency at the assemblage level. [ABSTRACT FROM AUTHOR]

An impact at Chicxulub, Mexico, occurred 66 million years ago, producing a global stratigraphic layer that marks the boundary between the Cretaceous and Paleogene eras. That layer contains elevated concentrations of platinum-group elements, including ruthenium. We measured ruthenium isotopes in samples taken from three Cretaceous-Paleogene boundary sites, five other impacts that occurred between 36 million to 470 million years ago, and ancient 3.5-billion- to 3.2-billion-year-old impact spherule layers. Our data indicate that the Chicxulub impactor was a carbonaceous-type asteroid, which had formed beyond the orbit of Jupiter. The five other impact structures have isotopic signatures that are more consistent with siliceous-type asteroids, which formed closer to the Sun. The ancient spherule layer samples are consistent with impacts of carbonaceous-type asteroids during Earth's final stages of accretion. [ABSTRACT FROM AUTHOR]

Simple Summary: ImmunoPET involves tagging an antibody (a protein that targets cancer cells) with a radioactive substance that can be seen by imaging. This could non-invasively visualize where cancer is and how much of the target antigen is present, helping decide which patients should get radioimmunotherapy. This therapy uses the same antibody but with a different radioactive substance designed to kill cancer cells. ImmunoPET shows where the cancer is and how much there is, helping choose the right patients for treatment. It helps monitor how well the treatment is working, so adjustments can be made if necessary. It provides important data on how the antibody moves and clears in the body, which helps in calculating the right dose and optimizing the treatment plan. This strategy can lead to more targeted and personalized therapies with fewer side effects because it leverages the precision of antibodies and the powerful effects of radiation. The combination of immunoPET—where an antibody (Ab) is labeled with an isotope for PET imaging—and radioimmunotherapy (RIT), using the same antibody with a therapeutic isotope, offers significant advantages in cancer management. ImmunoPET allows non-invasive imaging of antigen expression, which aids in patient selection for subsequent radioimmunotherapy. It also facilitates the assessment of tumor response to therapy, allowing for treatment adjustments if necessary. In addition, immunoPET provides critical pharmacokinetic data, including antibody biodistribution and clearance rates, which are essential for dosimetry calculations and treatment protocol optimization. There are still challenges to overcome. Identifying appropriate target antigens that are selectively expressed on cancer cells while minimally expressed on normal tissues remains a major hurdle to reduce off-target toxicity. In addition, it is critical to optimize the pharmacokinetics of radiolabeled antibodies to maximize tumor uptake and minimize normal tissue uptake, particularly in vital organs such as the liver and kidney. This approach offers the potential for targeted and personalized cancer therapy with reduced systemic toxicity by exploiting the specificity of monoclonal antibodies and the cytotoxic effects of radiation. However, further research is needed to address remaining challenges and to optimize these technologies for clinical use. [ABSTRACT FROM AUTHOR]

High Ba-Sr granites are geochemically distinct from the more familiar I-, S- and A-types (of igneous, sedimentary or anorogenic/anhydrous/alkaline parentage), in particular by their lack of depletion in Ba and Sr relative to other large-ion lithophile elements (LILE). These differences are sufficient enough to indicate different petrogenetic processes which are still the subject of considerable debate. High Ba-Sr plutons from the classic Caledonian type location in NW Scotland show a range of elemental and isotopic enrichment, ideal for novel petrogenetic investigations such as the application of "non-traditional" stable isotope systems. Two directly comparable plutons have been analysed for Ba and Mg isotopes, from either end of the range of enrichment. Barium isotopes (δ 138/134Ba values of −0.05 to +0.23 ‰ in the relatively "depleted" Strontian pluton and −0.19 to +0.03 ‰ in the enriched Rogart comparator) overlap normal mantle values but extend to lighter compositions, consistent with addition of up to 5 % pelagic sediment that has incorporated variable amounts of biogenic barite. Magnesium isotopes (δ26Mg values of −0.30 to −0.25 ‰ versus −0.42 to −0.23 ‰ in Strontian and Rogart, respectively) lie largely within the normal mantle range, with two light outliers possibly indicative of carbonate involvement but for which fractional crystallization cannot be excluded. Associated relationships between fluid-mobile and melt-mobile elements suggest that sediment melting transfers the crustal isotope signature to a dominantly mantle source, itself variable between isotopically depleted mantle wedge and previously enriched lithospheric mantle. The combined Ba, Mg, O, Sr, and Nd isotope and elemental data are all consistent with a small percentage of pelagic sediment in a mantle source for high Ba-Sr granites, and this is sufficient to disguise these essentially mantle-derived rocks as reworked continental crust. First-order estimates suggest that some 10 % of granites worldwide may have high Ba-Sr character, although the proportion of these that represent largely juvenile origin is currently unknown. Nevertheless, as compositional equivalents of Archean sanukitoids, they may represent unrecognized mantle contributions to crustal growth over some 3 billion years of Earth history. [ABSTRACT FROM AUTHOR]

Tektite and microtektite formation have important implications on our understanding of impacts both on Earth, the Moon and on other bodies within our solar system. Here, we investigate the formation mechanisms of microtektites by analysing the K isotope systematics and elemental compositions of forty-four Australasian microtektites from various distances from the proposed impact location. Based on the K isotope and concentration data, the microtektites analyzed here are split into two groups, the "ODP group" and the "MB group". The ODP group were recovered from the Ocean Drilling Project (ODP) sediment cores and consist of microtektites which landed closer to the proposed impact site (∼1220–1240 km) and show limited δ41K variation (–1.06 ‰ to −0.21 ‰) and higher K concentrations (2.48 wt% to 3.66 wt% K 2 O). In contrast, the MB group were mostly collected from the surface of Miller Butte (MB) in Antarctica and represent microtektites which landed significantly further from the proposed impact site (∼4100–10800 km) and contain large δ41K variations (−4.04 ‰ to 0.57 ‰) and low K concentrations (0.49 wt% to 1.45 wt% K 2 O). For the microtektites studied here, the overall correlation observed is consistent with condensation whereby a greater extent of K depletion correlates with lighter K isotope compositions. This simple condensation model is in contrast to previous studies which find evidence for complex evolution involving evaporation, condensation, and mixing. For the ODP group microtektites, the isotopic and elemental data suggest condensation from an upper continental crust (UCC) starting composition. Conversely, for the MB group a UCC starting composition is not compatible, as even the most K-rich MB group microtektites are significantly depleted in K and display δ41K values much higher than the UCC. These observations can be explained by a vapor plume with a progressively evolving K isotope composition, with the earliest K condensates depleting and fractionating K within the plume, thus altering the starting K compositions for the later K condensates. From this data we calculate a cooling rate of up to 2,600 K/hour for the ODP group and up to 20,000 K/hour for the MB group, which are comparable to the cooling rates measured for tektites and considerably faster than those theoretically calculated or experimentally determined for chondrules. Overall, when assessed within the context of previous studies, microtektite formation appears very complex with evidence for different volatilization processes to different degrees observed within different microtektites. As such, while condensation appears dominant for K within the Australasian microtektites studied here, more work is needed to fully untangle the processes involved in microtektite formation. [ABSTRACT FROM AUTHOR]

We introduce a new isotope chronological model in which the natural mass-dependent isotopic fractionation effects of the radioactive ("parent") and radiogenic ("daughter") elements are systematically and rigorously considered. Using this model, we show that internally-normalized radiogenic isotopic ratios, commonly determined for daughter elements such as Sr, Nd, Cr, Ni, Hf, W, and Os, are dependent on the extent of natural isotopic fractionation of the daughter and parent elements at the time of system closure. This dependence indicates that (1) in two samples derived from the same isotopically homogeneous source at the same time and with identical radiogenic ingrowth over time, the present-day internally-normalized radiogenic isotope ratios would be different if they were initially fractionated to different degrees, and (2) if different internally-normalized radiogenic isotopic ratios are observed for two co-genetic objects, the difference between them would include contributions from both radiogenic ingrowth and natural isotopic fractionation. Consequently, the isochron dating equations employed in traditional chronological studies will yield inaccurate results when significant natural isotopic fractionation is present among the studied samples. Modified isochron equations that can be used to retrieve correct chronological information from isotopically-fractionated samples are presented. These theoretical considerations are applied to the 87Rb–87Sr, 147Sm–143Nd, and 146Sm–142Nd isotope systems of calcium–aluminium-rich inclusions (CAIs), a set of samples that have undergone significant natural Sr, Nd, and Sm isotope fractionation during their formation. The large natural Sr isotope fractionation (up to ca. 5.3 ‰ for 88Sr/86Sr) in fine-grained CAIs can generate analytically well-resolvable biases (>120 ppm) in the internally-normalized 87Sr/86Sr ratios and lead to significant scatters of their 87Rb–87Sr isochron (in conjunction with scatters induced by open-system disturbances). The 87Rb–87Sr systems of coarse-grained CAIs, on the contrary, are essentially not affected by natural Sr isotopic fractionation due to their much subdued fractionation degrees, resulting in a more robust isochron. Similarly, the large natural Nd (up to ca. 4.0 ‰ for 146Nd/144Nd) and Sm (up to ca. 7.1 ‰ for 152Sm/148Sm) isotopic fractionation in fine-grained CAIs can induce significant scatters of the 147Sm–143Nd isochron if the natural fractionation followed the kinetic or power law, and 146Sm–142Nd isochron if the natural fractionation followed the equilibrium, Rayleigh, or power law. This implies that when studying radioactive isotope systems in objects whose daughter and parent elements can undergo significant isotope fractionation in nature, accompanying stable isotope analyses are necessary for accurate chronological interpretations. [ABSTRACT FROM AUTHOR]

Reduced-scale CO2 release experiments in shallow aquifers serve as crucial monitoring strategies for detecting unintended CO2 leakage into potable aquifers within Carbon Capture and Storage (CCS) projects. Understanding site-specific geological, hydrogeological, and climatic features is essential. However, accurately tracing changes in groundwater quality due to this process and using hydrochemical parameters for CO2 leakage diagnosis require establishing a solid, seasonally relevant baseline to avoid misinterpretation. This study focuses on detailing the geological, hydrogeological, and geophysical characteristics of the TECNOPUC-Viamão CO2 controlled-release experimental site in Rio Grande do Sul, Brazil. It presents a comprehensive three-year investigation into the seasonal natural background hydrochemistry. Field characterization involved recognition boreholes, in-situ infiltration and Slug Tests, topographic surveys, DC resistivity measurements, and groundwater sampling campaigns for physicochemical, major, minor, trace elements, and δ¹³C-DIC evaluation. Results indicate the area comprises a granite-derived multilayer phreatic aquifer with two distinct hydrostratigraphic units (St and Aa). These units differ in lithological composition, hydraulic conductivities (St: 10− 4 m/s, Aa: 10− 8 m/s), apparent resistivities, and physicochemical and hydrochemical compositions. The St unit shows slightly neutral pH, higher temperature, EC, ORP, DO, Ca, Mg, K, Fe, Mn, Sr, B, HCO3−, and DIC concentrations, with δ¹³C-DIC between − 3 to -8‰. Conversely, the Aa unit displays slightly acidic pH, lower temperature, EC, ORP, higher DO fluctuation, Na, SO42−, Cl−, NO3−, Zn, Al, Ni concentrations, lower HCO3−, DIC levels, with δ¹³C-DIC ranging between − 6 to -11‰. Additionally, seasonal monitoring campaign revealed that there is a clear temperature-related influence on K, Na and trace elements (Fe, Ba, Mn, Al, B, and Zn) behavior (but not in Ca, Mg, Sr and Ni), which could impact further interpretation of the results during the upcoming CO2 injection phase, and that the Control Charts can confidently serve as a valuable tool in understanding the inherent natural hydrochemical trends. [ABSTRACT FROM AUTHOR]

Alaska's boreal forests are experiencing rapid changes in climate that may favor deciduous-dominated systems, with important implications for global biogeochemical and energy cycles. However, aspen (Populus tremuloides Michx.) has experienced substantial defoliation from the aspen leaf miner (Phyllocnistis populiella Cham., hereafter ALM) in Alaska, resulting in significant growth reductions. We conducted a tree-ring and Δ13C study to test the hypothesis that moisture limitation may have predisposed aspen to leaf miner damage. Contrary to our hypothesis, differences in climate-growth correlations between relatively severely and lightly affected trees were negligible during the pre-outbreak decades. Stands with greater summer precipitation had more limited ALM impact, however differences among models were small and multiple climate variables were suitable predictors of ALM impact. The strong negative relationship we detected between tree-ring Δ13C and basal area increment (BAI) suggested that interannual variation in Δ13C was driven primarily by variation in photosynthesis, limiting the utility of Δ13C as a tool to detect stomatal responses to moisture-limitation. Instead, we found that larger, faster-growing individuals on gentler slopes showed a stronger absolute reduction in BAI (pre-ALM BAIffpost-ALM BAI), but were similar in relative BAI reduction (pre-ALM BAI/post-ALM BAI), with smaller, slower growing trees. Older trees and stands with greater relative abundance of white spruce [Picea glauca (Moench) Voss] had greater relative ALM impact whereas slower growing trees on steeper slopes were less affected. The significant effect of white spruce abundance on ALM impact was likely due to favorable leaf miner overwintering habitat provided beneath white spruce trees, which can lead to increased leaf miner survival and thus greater reductions in aspen growth. Our results illustrate the subtle but complex biotic interaction between microclimate and pest physiology in determining ALM-induced aspen growth reductions, adding important nuance to a hypothesized increase in deciduous tree cover in Alaska's boreal forest. [ABSTRACT FROM AUTHOR]

Stable isotope techniques are precise methods for studying various aspects of hydrology, such as precipitation characteristics. However, understanding the variations in the stable isotope content in precipitation is challenging in Iran due to numerous climatic and geographic factors. To address this, forty-two precipitation sampling stations were selected across Iran to assess the fractional importance of these climatic and geographic parameters influencing stable isotopes. Additionally, deep learning models were employed to simulate the stable isotope content, with missing data initially addressed using the predictive mean matching (PMM) method. Subsequently, the recursive feature elimination (RFE) technique was applied to identify influential parameters impacting Iran's precipitation stable isotope content. Following this, long short-term memory (LSTM) and deep neural network (DNN) models were utilized to predict stable isotope values in precipitation. Interpolated maps of these values across Iran were developed using inverse distance weighting (IDW), while an interpolated reconstruction error (RE) map was generated to quantify deviations between observed and predicted values at study stations, offering insights into model precision. Validation using evaluation metrics demonstrated that the model based on DNN exhibited higher accuracy. Furthermore, RE maps confirmed acceptable accuracy in simulating the stable isotope content, albeit with minor weaknesses observed in simulation maps. The methodology outlined in this study holds promise for application in regions worldwide characterized by diverse climatic conditions. [ABSTRACT FROM AUTHOR]

An important method for measuring radionuclide activity is alpha spectrometry. Ten soil samples were collected from the studied area. The activity concentrations of 238U and 234U in the collected soil samples ranged between 135 and 218 Bq kg–1 and between 117 and 183 Bq kg–1, respectively. 232Th, 230Th and 228Th activity concentrations ranged between 101 and 339, between 122 and 234 and between 106 and 385 Bq kg–1, respectively. When calculating the amount of radionuclide transport across the food chain, assessment models usually employ a transfer factor. Through root uptake, U and Th are transferred from the soil to food plants. To monitor the movement of radionuclides from the uranium series in diverse environments, it may be possible to use the ratios of uranium and thorium isotopes. Uranium mobility in soil depends on different physicochemical, organic and enzymatic factors and mechanisms. The high mobility of uranium is the main reason for the accumulation of uranium in the soil at root level and the possibility of its transfer to plants. A group of plants were selected that are grown in this area and the population relies on them mainly to meet their food needs. The concentration and transfer factor values of uranium isotopes were the highest in roots as compared with leaves and stems. Uranium in plants accumulates in roots and is then transferred to leaves. The mobility of uranium in plant tissues is constrained because it frequently adsorbs cell wall components. As a result, concentrations are frequently higher in tissues located in lower parts of the plant, with root surfaces having the highest concentrations. [ABSTRACT FROM AUTHOR]

Using the Coulomb and Proximity Potential Model (CPPM) and a Q-value dependent surface diffuseness parameter in the proximity potential, the alpha decay half-lives of 75 experimentally synthesized superheavy nuclei were determined. Comparisons are made between the obtained results and experimentally determined alpha decay half-lives, as well as the predictions of Yang et al.'s recent study [Nucl. Phys. A 1014 (2021) 122250], which is based on the Unified Fission Model (UFM) with a new preformation parameter. The lowest standard deviation of 0.621 is obtained for CPPM calculations with Q-value-dependent surface diffuseness parameter. The calculation is extended further to estimate the alpha decay half-lives of 2 8 4 − 3 1 5 119 and 2 8 7 − 3 1 6 120 superheavy isotopes and compared with the predictions of UFM. Finally, the results of the calculations are compared to the predictions of the UDL formula [Phys. Rev. Lett. 103 (2009) 072501] and the modified Hutsukawa formula [Nucl. Part. Phys. Proc. 339 (2023) 92]. [ABSTRACT FROM AUTHOR]

Accurate estimates of water isotope diffusion lengths are crucial when reconstructing and interpreting water isotope records from ice cores. This is especially true in the deepest, oldest sections of deep ice cores, where thermally enhanced diffusive processes have acted over millennia on extremely thinned ice. Previous statistical estimation methods, used with great success in shallower, younger ice cores, falter when applied to these deep sections, as they fail to account for the statistics of the climate on millennial timescales. Here, we present a new method to estimate the diffusion length from water isotope data and apply it to the Marine Isotope Stage 19 (MIS 19) interglacial at the bottom of the EPICA Dome C (EDC, Dome Concordia) ice core. In contrast to the conventional estimator, our method uses other interglacial periods taken from further up in the ice core to estimate the structure of the variability before diffusion. Through use of a Bayesian framework, we are able to constrain our fit while propagating the uncertainty in our assumptions. We estimate a diffusion length of 31±5 cm for the MIS 19 period, which is significantly smaller than previously estimated (40–60 cm). Similar results were obtained for each interglacial used to represent the undiffused climate signal, demonstrating the robustness of our estimate. Our result suggests better preservation of the climate signal at the bottom of EDC and likely other deep ice cores, offering greater potentially recoverable temporal resolution and improved reconstructions through deconvolution. [ABSTRACT FROM AUTHOR]

We document the isotopic evolution of near-surface snow at the East Greenland Ice Core Project (EastGRIP) ice core site in northeast Greenland using a time-resolved array of 1 m deep isotope (δ18O , δD) profiles. The snow profiles were taken from May–August during the 2017–2019 summer seasons. An age–depth model was developed and applied to each profile, mitigating the impacts of stratigraphic noise on isotope signals. Significant changes in deuterium excess (d) are observed in surface snow and near-surface snow as the snow ages. Decreases in d of up to 5 ‰ occur during summer seasons after deposition during two of the three summer seasons observed. The d always experiences a 3 ‰–5 ‰ increase after aging 1 year in the snow due to a broadening of the autumn d maximum. Models of idealized scenarios coupled with prior work indicate that the summertime post-depositional changes in d (Δd) can be explained by a combination of surface sublimation, forced ventilation of the near-surface snow down to 20–30 cm , and isotope-gradient-driven diffusion throughout the column. The interannual Δd is also partly explained with isotope-gradient-driven diffusion, but other mechanisms are at work that leave a bias in the d record. Thus, d does not just carry information about source-region conditions and transport history as is commonly assumed, but also integrates local conditions into summer snow layers as the snow ages through metamorphic processes. Finally, we observe a dramatic increase in the seasonal isotope-to-temperature sensitivity, which can be explained solely by isotope-gradient-driven diffusion. Our results are dependent on the site characteristics (e.g., wind, temperature, accumulation rate, snow properties) but indicate that more process-based research is necessary to understand water isotopes as climate proxies. Recommendations for monitoring and physical modeling are given, with special attention to the d parameter. [ABSTRACT FROM AUTHOR]

To meet the growing demand for intraoperative molecular imaging, the development of compatible imaging agents plays a crucial role. Given the unique requirements of surgical applications compared to diagnostics and therapy, maximizing translational potential necessitates distinctive imaging agent designs. For effective surgical guidance, exogenous signatures are essential and are achievable through a diverse range of imaging labels such as (radio)isotopes, fluorescent dyes, or combinations thereof. To achieve optimal in vivo utility a balanced molecular design of the tracer as a whole is required, which ensures a harmonious effect of the imaging label with the affinity and specificity (e.g., pharmacokinetics) of a pharmacophore/targeting moiety. This review outlines common design strategies and the effects of refinements in the molecular imaging agent design on the agent's pharmacological profile. This includes the optimization of affinity, pharmacokinetics (including serum binding and target mediated background), biological clearance route, the achievable signal intensity, and the effect of dosing hereon. [ABSTRACT FROM AUTHOR]

In electrochemistry, φ can be calculated via φΘ and Nernst equation. Current physical chemistry textbooks only provide substances’ φΘ under acidic conditions and corresponding practices. Hence, the calculation of φ works well under acidic conditions. However, it becomes complicated under alkaline conditions for some substances cannot exist in acidic conditions. These might lead to incorrect results and confused conclusions. To address this issue, the present study calculates φΘ (φBΘ) from ∆rGm Θ based on ∆fGm Θ of involved substances in redox half reaction. Then, φ at different pH is calculated via Nernst equation, resulting in a φ−pH diagram. Moreover, thermodynamic isotope effects on φΘ and φ are included. This may serve as a reference for teaching and research purposes. [ABSTRACT FROM AUTHOR]

The elemental and isotopic properties of garnet pyroxenites can yield information on lithospheric mantle composition, thermal state, and evolution. The 34Ma Kakanui Mineral Breccia in New Zealand contains spectacular but little-studied mantle peridotite and pyroxenite xenoliths that yield new insights into the evolution of a portion of the underlying mantle lithosphere of a former Gondwana margin. The moderately depleted and metasomatized spinel peridotites, as judged from spinel and olivine compositions and bulk rock major and platinum group element abundances, give mineral equilibration temperatures <1020°C and are derived from the middle to shallow (~35 to 50 km) lithospheric mantle when projected onto a 70 mW∙m−2 geotherm. These residues have low Re/Os and Re-depletion 187Os/188Os model ages that range from Eocene (0.05 Ga) to Paleoproterozoic (1.9 Ga), consistent with extraction from a lithospheric mantle comprising fragments with complex depletion histories. Although the peridotites have restricted δ18O (olivine +5.2 to 6.2), evidence for an isotopically heterogeneous mantle column in addition to the 187Os/188Os is seen in clinopyroxene 87Sr/86Sr (0.70244 to 0.70292), εNd (+4.1 to 18.8), 206Pb/204Pb (17.8 to 20.3), and εHf (+10 to +101). Higher metamorphic equilibrium temperatures of the garnet pyroxenites (Fe–Mg exchange of >1150°C) compared to the peridotites indicate their Eocene extraction was from towards the base of this isotopically heterogeneous mantle lithosphere. Pyroxenite bulk compositions point to cumulate origins, and the mineral isotope ratios of 87Sr/86Sr (0.70282 to 0.70294), εNd (+5.5 to 8.0) and 206Pb/204Pb (18.1 to 19.3) match many of the Zealandia metasomatized mantle peridotite xenoliths as well as the primitive intraplate basalts but not the garnet pyroxenite host magmas. In contrast to many global pyroxenite studies, the garnet pyroxenite 87Sr/86Sr and δ18O (+5.2 to 5.8) data provide no evidence for subducted crustal material in the primary magma source region, and Sm–Nd and Lu–Hf isotope data yield mid-Cenozoic ages that are probably related to isotope closure during eruption. An exception is one sample that yields a Lu–Hf isochron age of 111.9 ± 9.1 Ma, which corresponds to the convergence of the Lu–Hf isotope evolution curves of three other samples. Liquids calculated to have been in equilibrium with these cumulates have trace element compositions comparable to primitive alkaline intraplate basalts like those found at the surface of Zealandia. The new data, therefore, indicate that a pulse of intraplate magmatism occurred during or directly after the cessation of long-lived subduction on the former Zealandia Early Cretaceous forearc Gondwana margin, despite any volcanic surface exposure having been long eroded away. The lower lithospheric mantle emplacement of the garnet pyroxenites suggests that the source of the alkaline parent magmas was probably the convecting mantle, which supports conclusions that intraplate magmas in Zealandia have asthenospheric and lithospheric mantle sources. [ABSTRACT FROM AUTHOR]

Simple Summary: Brain metastases are cancerous growths that spread to the brain from other parts of the body, causing severe health problems. This review explores brachytherapy, a treatment where radioactive sources are placed directly into or near tumors or tumor beds to deliver targeted radiation, with the goal of minimizing damage to healthy brain tissue. Here, we aim to summarize the history and recent advancements of brachytherapy techniques and clinical outcomes in brain metastasis treatment, showcasing its benefits and limitations and providing a clearer understanding of how brachytherapy may potentially improve quality of life for patients with brain metastases. Brain metastases pose a significant therapeutic challenge in the field of oncology, necessitating treatments that effectively control disease progression while preserving neurological and cognitive functions. Among various interventions, brachytherapy, which involves the direct placement of radioactive sources into or near tumors or into the resected cavity, can play an important role in treatment. Current literature describes brachytherapy's capacity to deliver targeted, high-dose radiation while minimizing damage to adjacent healthy tissues—a crucial consideration in the choice of treatment modality. Furthermore, advancements in implantation techniques as well as in the development of different isotopes have expanded its efficacy and safety profile. This review delineates the contemporary applications of brachytherapy in managing brain metastases, examining its advantages, constraints, and associated clinical outcomes, and provides a comprehensive understanding of advances in the use of brachytherapy for brain metastasis treatment, with implications for improved patient outcomes and enhanced quality of life. [ABSTRACT FROM AUTHOR]

Accessory vessels, including platters, dishes, beakers, flagons, jars, and amphorae, are a common feature of Romano-British burials, raising questions as to their provenance; for example, were such vessels recycled from the domestic sphere or made specially for funerary purposes? Furthermore, uncertainty surrounds their purpose: did they contain foods for the deceased, possibly for their final journey to the underworld? Interestingly, organic residue analysis of vessels from Baginton, a site adjacent to The Lunt fort, Coventry, an early (mid to late first century) Roman military cremation cemetery did not yield evidence for food offerings and may have reflected the use of seconds or damaged vessels in burials, perhaps to provide a symbolic meal. In contrast, here we provide, for the first time, direct chemical and isotopic evidence for ‘meals for the dead’, comprising mainly dairy products, often mixed with leafy plants, extracted from somewhat unusual accessory vessels found in a small, enclosed inhumation cemetery, perhaps associated with a family group, which dates to the late (third to late fourth century, or early fifth century A.D) in urban Canterbury. Thus, we can confirm that accessory vessels found in later Romano-British burials were, in this instance, used in the laying out of funerary meals, presumably to nourish the soul on the journey to the underworld. These preliminary insights on vessel use and burial practices across the span of the Roman occupation of Britain thus provide a strong hint at the diversity of Roman burial practices. [ABSTRACT FROM AUTHOR]

The reconstruction of the Early Paleozoic collision metamorphism of the Khan-Khukhei Block (Northern Mongolia) based on 3D modeling of thermal state of the crust and isotope dating is presented. The age of garnet–biotite schist from a metamorphic complex of the Khan-Khukhei Block of 517.4 ± 7.4 Ma is determined for the first time. 3D modeling was conducted to compare this age of metamorphism with the available age determinations of (post-) collision granite formation in the range of 513‒505 Ma. The model considers radiogenic heating at an elevated heat production of rocks of the thickened crust of the Khan-Khukhei block as the cause of the migmatization and granitoid melts formation. 3D modeling was conducted for the first time for thermal-dome type of metamorphism. The results provide a realistic conception of magma generation in typical collision settings in the absence of mantle magmatic heat sources. The time interval between metamorphism and the stage of anatectic magma formation is 5–12 Ma. [ABSTRACT FROM AUTHOR]

The Baoshan deposit is one of the important Cu-Pb-Zn deposits associated with granitic rocks in the Nanling Range, South China. Here, we present He and Ar isotope data for the Baoshan deposit to decipher the contributions of mantle-derived volatiles and heat to its Cu-Pb-Zn mineralization. The ore-forming fluids in sphalerite and pyrite exhibited 3He/4He ratios up to 1.51 Ra. A linear correlation between He and Ar isotopes suggests that the ore-forming fluids were a mixture of a predominantly mantle-derived fluid with a high 3He/4He ratio and a shallow crustal fluid, characterized by a low 3He/4He ratio. The δ34S values of sulfides in the Baoshan deposit ranged from +2.30 to +5.21‰, consistent with the magma-derived sulfur. The calculated 3He/Q ratios for the ore-forming fluid exceeded those of mid-oceanic ridge hydrothermal solutions by 10 to 50 times, indicating that the ore-forming fluids acquired both heat and volatiles in a convective hydrothermal regime rather than a conductive one. Therefore, there is a significant contribution of mantle-derived volatiles, heat, and possibly metals, to the Cu-Pb-Zn mineralization in the Baoshan deposit, and the continuous influx of mantle-derived fluids/melts probably plays a crucial role during the Cu-Pb-Zn mineralization related to granitic rocks. [ABSTRACT FROM AUTHOR]

The study of Neoproterozoic carbonate sequences is complicated due to several variables influencing the geochemical and mineralogical composition, compounded by the scarcity of environmental analogs. The Tamengo Formation in the Corumbá Group is one of the most extensively studied archives of the Neoproterozoic in South America and encompasses Ediacaran guide fossils of Corumbella werneri and Cloudina lucianoi. This research focused on a marl sample containing well-preserved bioclasts of exoskeletons of Corumbella werneri, which is one of the earliest biomineralizing organisms. By utilizing diverse techniques such as optical and SEM microscopy, QEMSCAN imaging, electron microprobe, in situ ICP-MS, and isotope analyses, this study reveals primary and secondary signals in the bioclastic exoskeletons and the matrix within. These findings shed light on the sedimentary environment and diagenetic history of the Tamengo Formation. It is revealed that Corumbella werneri likely inhabited calm conditions, just below the base of storm waves and above a sharp chemocline at the bottom. In addition, the presence of distinct hydrothermal signals in the composition of REEs indicates a potential magmatic event that occurred in the region after the deposition of the succession. This pilot study highlights that the history recorded in the Neoproterozoic rocks of the Tamengo Formation is complex, and thus more detailed studies integrating lithological, paleontological, and geochemical parameters are necessary to reach a correct interpretation of this sequence. [ABSTRACT FROM AUTHOR]