Search

A short review of the most important (arbitrary choice) papers published by Prof. Stanisław Szpikowski (1926-2014) is presented. A short review of the most important (arbitrary choice) papers published by Prof. Stanisław Szpikowski (1926-2014) is presented. Professor dr hab. Stanisław Szpikowski began his adventure with physics as the experimentalist. As the research-and-teaching vice-assistant in the Cathedral of Experimental Physics of the Maria Curie-Skłodowska University (UMCS) he started to work on thermodiffusion measuring the thermodiffusion coefficients for different elements and their isotopes (Kilka uwag dotyczących doświadczalnego wyznaczania stałej dyfuzji termicznej dla izotopów, Annales UMCS, Sectio AA, vol. VIII (1953) 35-56). Next he prepared some experiments which allow to observe some parameters and evolution of thermodiffusion in gases (Wyznaczanie stałych potencjału wodoru, dwutlenu węgla i mieszaniny, H2 - CO2, H2 - CO2 Annales UMCS, Sectio AA, vol. XIV (1959) 1-27; Przebieg termodyfuzyjny mieszaniny w zależności od czasu temperatury, ciśnienia oraz składu mieszaniny, Annales UMCS, Sectio AA, vol. XIV (1959) 29-48; Thermodiffusion process of gases in a horizontal tube, Folia Soc. Scient. Lublinensis, Sectio C, 2 (1962) 116-119; Thermodiffusion process of gases in a horizontal tube. Experimental part, Folia Soc. Scient. Lublinensis, Sectio C, vol 5/6 (1965/66) 3-5). On the other hand, it was the first time when Prof. Szpikowski started to think about theoretical physics. He considered the contemporary theory of thermodiffusion using the simplified thermodiffusion equation: Γk/n = -D12 ΔCk + (-1)k+1 DT/T ΔT, which contains the measurable thermodiffusion constant α: DT/D12 = αC1C2. [ABSTRACT FROM AUTHOR]

Dietary reconstruction is used to make inferences about the subsistence strategies of ancient human populations, but it may also serve as a proxy to characterise their diverse cultural and technological manifestations. Dental microwear and stable isotope analyses have been shown to be successful techniques for paleodietary reconstruction of ancient populations but, despite yielding complementary dietary information, these techniques have rarely been combined within the same study. Here we present for the first time a comprehensive approach to interpreting ancient lifeways through the results of buccal and occlusal microwear, and δ 13 C and δ 15 N isotope analyses applied to the same individuals of prehistoric populations of Hungary from the Middle Neolithic to the Late Bronze Age periods. This study aimed to (a) assess if the combination of techniques yields a more precise assessment of past dietary and subsistence practices, and (b) contribute to our understanding of the dietary patterns of the prehistoric Hungarian populations. Overall, no correlations between microwear and δ 13 C and δ 15 N isotope variables were observed, except for a relationship between nitrogen and the vertical and horizontal index. However, we found that diachronic differences are influenced by the variation within the period. Particularly, we found differences in microwear and isotope variables between Middle Neolithic sites, indicating that there were different dietary practices among those populations. Additionally, microwear results suggest no changes in the abrasiveness of the diet, neither food processing methods, despite higher C 4 plant resource consumption shown by carbon isotopic signal. Thus, we demonstrate that the integration of dental microwear and carbon and nitrogen stable isotope methodologies can provide complementary information for making inferences about paleodietary habits.

This document provides an overview of the use of environmental isotopes in hydrogeology, focusing on the importance of groundwater as a vital resource and addressing issues such as water scarcity, overexploitation, and contamination. It explains how isotopes can be used to identify the origin and replenishment rates of groundwater systems, assess groundwater contamination, and understand groundwater dynamics. The document includes research papers that demonstrate the application of isotopes in various hydrogeological contexts. It concludes by emphasizing the need for comprehensive isotopic studies to support the sustainable management of groundwater resources. The authors express gratitude to the researchers and reviewers who have contributed to a Special Issue and acknowledge the valuable comments that have improved the outcome of the issue. [Extracted from the article]

The H2 18O stable isotope was previously introduced in the three coupled components of the Earth System Model iLOVECLIM: atmosphere, ocean and vegetation. The results of a long (5000 yr) pre-industrial equilibrium simulation are presented and evaluated against measurement of H2 18 O abundance in present-day water for the atmospheric and oceanic components. For the atmosphere, it is found that the model reproduces the observed spatial distribution and relationships to climate variables with some merit, though limitations following our approach are highlighted. Indeed, we obtain the main gradients with a robust representation of the Rayleigh distillation but caveats ap pear in Antarctica and around the Mediterranean region due to model limitation. For the oceanic component, the agreement between the modelled and observed distribution of water δ18O is found to be very good. Mean ocean surface latitudinal gradients are faithfully reproduced as well as the mark of the main intermediate and deep water masses. This opens large prospects for the applications in paleoclimatic context. [ABSTRACT FROM AUTHOR]

Cu isotope ratios have been widely applied to fingerprinting metal sources, tracking fluid pathways, and tracing mineralization processes, for which knowledge of isotope fractionation is required. This paper presents new experimental calibration data of Cu isotope fractionation between Cu-bearing minerals (native Cu and cuprite) and Cl-bearing hydrothermal fluids at 25–800 °C and 0.1–200 MPa. The experiments were performed either using a polytetrafluoroethylene (Teflon) beaker on a hotplate, a rapid heat/rapid quench argon cold seal pressure vessel (RH/RQ Ar-CSPV), or a large volume fluid reactor, which enabled fluid sampling ex situ (the former two) and in situ (the latter). Three setups were designed to investigate Cu isotope fractionation (Δ65Cufluid-mineral): (1) associated with Cu(I) dissolution, Cu(I) disproportionation as well as oxidation of Cu(0) (native copper) and Cu(I) in Cu ± Cu2O + HCl systems at temperatures of up to 800 °C and pressures of up to 200 MPa; (2) related to Cu-Au alloying processes in the Cu + NaCl/HCl system at 600 °C and 150 MPa; (3) to evaluate the influences of different sampling techniques (ex situ vs. in situ) and superimposed cooling processes. The selected system is Cu2O + NaCl + 0.2 m HAc/NaAc (pH-buffer), and runs were conducted at 200–250 °C and 20 MPa. Δ65Cufluid-mineral shows the least variation during solid separation from source fluids, generally <0.16 ± 0.03‰. Positive Δ65Cufluid-mineral values are found in most runs, excluding cuprite dissolution in NaCl/ HCl solutions at 200–250 °C, 20 MPa, and 800 °C, 200 MPa. Cu oxidative leaching into Cu(I) results in decreasing Δ65CuCu(I)-Cu(0) values from 0.12 ± 0.05% to 0.07 ± 0.05%, and –0.30 ± 0.03‰ at 25, 50, and 200 °C, respectively. In contrast, Cu dissolution at high temperatures (600–800 °C) leads to Cu(I)-containing quench fluids and subsequent native Cu precipitates. Both products are enriched in heavy isotopes by up to 5‰, caused by preferential enrichment of 65Cu at the surface layer during the alloying-induced diffusion transport process. Cuprite oxidative leaching in HCl leads to fluids enriched in Cu(II), and the corresponding Δ65CuCu(II)-Cu(I) increases from 0.52 ± 0.04‰ at 25 °C to 0.89 ± 0.02‰ at 50 °C. Fluids are enriched with light isotopes (63Cu) during cuprite dissolution at 200, 250, and 800 °C, i.e., 0–0.55 ± 0.04‰ lower than the precursor. At 250–300 °C, Cu(I) disproportionation into Cu(II) and Cu(0) dominates the observed isotope fractionation, yielding Δ65Cufluid-Cu2O up to 0.59 ± 0.03‰ and Δ65CuCu(0)-Cu2O up to –0.28 ± 0.02‰. Rapid cooling (3–25 K s–1) relative to slow cooling (0.014 K s–1) can cause phase separation as well as significant isotope fractionation, particularly if fluids cool from an intermediate high temperature to ambient temperature (e.g., from 200–300 to 25 °C), which highlights the importance of kinetic processes that may potentially alter the isotope composition of natural ore-forming fluids. [ABSTRACT FROM AUTHOR]

The article discusses the use of off-axis integrated cavity output spectroscopy to evaluate continuous water vapor isotope measurements. It examines the accuracy and precision of the laser based water vapor isotope instrument through a comparison of measurements with those found using the conventional cold trap method. The application of a commercially available water vapor isotope analyzer (WVIA) is also discussed.

Lists review papers in the "Journal of Materials Science" volumes 37, 38 and 39. Structure and properties of glass-like carbon; Stability of nanostructure materials; Applications of isotope effects in solids.

Deep-sea corals are a potentially valuable archive of the temperature and ocean chemistry of intermediate and deep waters. Living in near constant temperature, salinity and pH, and having amongst the slowest calcification rates observed in carbonate-precipitating biological organisms, deep-sea corals can provide valuable constraints on processes driving mineral equilibrium and disequilibrium isotope signatures. Here we report new data to further develop "clumped" isotopes as a paleothermometer in deep-sea corals as well as to investigate mineral-specific, taxon-specific, and growth-rate related effects. Carbonate clumped isotope thermometry is based on measurements of the abundance of the doubly-substituted isotopologue 13C18O16O2 in carbonate minerals, analyzed in CO2 gas liberated on phosphoric acid digestion of carbonates and reported as Δ47 values. We analyzed Δ47 in live-collected aragonitic scleractinian (Enallopsammia sp.) and calcitic gorgonian (Isididae and Coralliidae) deep-sea corals, and compared results to published data for other aragonitic scleractinian taxa. Measured Δ47 values were compared to in situ temperatures and the relationship between Δ47 and temperature was determined for each group to investigate taxon-specific effects. We find that aragonitic scleractinian deep-sea corals exhibit higher values than calcitic gorgonian corals and the two groups of coral produce statistically different relationship between Δ47-temperature calibrations. These data are significant in the interpretation of all carbonate "clumped" isotope calibration data as they show that distinct Δ47-temperature calibrations can be observed in different materials recovered from the same environment and analyzed using the same instrumentation, phosphoric acid composition, digestion temperature and technique, CO2 gas purification apparatus, and data handling. There are three possible explanations for the origin of these different calibrations. The offset between the corals of different mineralogy is in the same direction as published theoretical predictions for the offset between calcite and aragonite, although the magnitude of the offset is different. One possibility is that the deep-sea coral results reflect that crystals may attain nominal mineral equilibrium clumped isotope signatures only under conditions of extremely slow growth. In that case, a possible explanation for the attainment of disequilibrium bulk isotope signatures and equilibrium clumped isotope signatures by deep-sea corals is that extraordinarily slow growth rates can promote the occurrence of isotopic reordering in the interfacial region of growing crystals. We also cannot rule out a component of a biological "vital-effect" influencing clumped isotope signatures in one or both orders of coral. Based on published experimental data and theoretical calculations, these biological "vital" effects could arise from kinetic isotope effects due to the source of carbon used for calcification, temperature- and pH-dependent rates of CO2 hydration and/or hydroxylation, calcifying fluid pH, the activity of carbonic anhydrase, the residence time of dissolved inorganic carbon in the calcifying fluid, and calcification rate. A third possible explanation is the occurrence of variable acid digestion fractionation factors. Although a recent study has suggested that dolomite, calcite, and aragonite may have similar clumped isotope acid digestion fractionation factors, the influence of acid digestion kinetics on Δ47 is a subject that warrants further investigation. [ABSTRACT FROM AUTHOR]

Copyright of Acta Scientiarum Naturalium Universitatis Pekinensis is the property of Editorial Office of Acta Scientiarum Naturalium Universitatis Pekinensis and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We evaluate the isotopic composition of water vapor and precipitation simulated by the LMDZ GCM over Siberia using several datasets: TES and GOSAT satellite observations of tropospheric water vapor, GNIP and SNIP precipitation networks, and daily, in-situ measurements of water vapor and precipitation at the Kourovka site in Western Siberia. We use dD vs. humidity diagrams to explore the complementarity of these two variables to interpret model biases in terms of the representation of processes. LMDZ captures the spatial, seasonal and daily variations reasonably well. It systematically overestimates dD in the vapor and precipitation, a bias that is most likely associated with a misrepresentation of air mass origin. The performance of LMDZ is put in the context of other isotopic models from the SWING2 models. There is significant spread among models in the simulation of dD, and of the dD vs. humidity relationship. This confirms that dD brings additional information compared to humidity only. We specifically investigate the added value of water isotopic measurements to interpret the warm and dry bias feature by most GCMs over mid and high latitude continents in summer. LMDZ simulates the strongest dry bias on days when it simulates the strongest enriched bias in dD. The analysis of the slopes in dD vs. humidity diagrams and of processes controlling dD and humidity variations suggests that the cause of the moist bias could be either a problem in the large-scale advection transporting too much dry and warm air from the south, or insufficient surface evaporation. [ABSTRACT FROM AUTHOR]

This document is a correction notice for a research paper titled "Isotope Ratio Outlier Analysis (IROA) for HPLC–TOFMS-Based Metabolomics of Human Urine." The authors explain that they made deviations from the manufacturer's protocol for the IROA TruQuant IQQ Workflow Kit for specific reasons. They provide a detailed comparison of the dilutions they used and the recommended protocol, as well as additional experiments they conducted using upgraded software. The document includes information on sample preparation, software parameters, and the results obtained, including a table, graphs, and references. The authors state that the correction to the supplementary materials does not alter the scientific conclusions of the original publication. [Extracted from the article]

This paper aims to re-examine the dietary practices of individuals buried at Sigatoka Sand Dunes site (Fiji) in Burial Ground 1 excavated by Simon Best in 1987 and 1988 using two approaches and a reassessment of their archaeological, bioarchaeological and chronological frame. First, stable carbon and nitrogen isotope analysis was applied to document dietary changes between childhood and adulthood using an intra–individual approach on paired bone–tooth. Second, the potential adaptation of the individuals to their environment was evaluated through regional and temporal comparisons using inter–individual bone analysis. Ten AMS radiocarbon dates were measured directly on human bone collagen samples, placing the series in a range of approximately 600 years covering the middle of the first millennium CE (1,888 to 1,272 cal BP). δ13C and δ15N ratios were measured on bone and tooth collagen samples from 38 adult individuals. The results show that δ15N values from tooth are higher than those s from bone while bone and tooth δ13C values are similar, except for females. Fifteen individuals were included in an intra–individual analysis based on paired bone and tooth samples, which revealed six dietary patterns distinguished by a differential dietary intake of marine resources and resources at different trophic levels. These highlight sex–specific differences not related to mortuary practices but to daily life activities, supporting the hypothesis of a sexual division of labour. Compared to other Southwest Pacific series, Sigatoka diets show a specific trend towards marine food consumption that supports the hypothesis of a relative food self–sufficiency requiring no interactions with other groups. [ABSTRACT FROM AUTHOR]

This paper describes the assembly of an updated dataset of detrital zircon geochronology and Lu–Hf isotopes for Turkey, Cyprus and Greek peninsula. This first version of the dataset documented 286 samples with detrital zircon U–Pb data and 70 samples with zircon Lu–Hf isotopes from 42 published articles. These samples are mainly distributed in seven geologic‐tectonic units in the Eastern Mediterranean Tethyan region. The compilation of dataset will be periodically accessed in the Deep‐Time Digital Earth repository, containing more updated raw data of (un)published scientific research. We believe that the construction of such a dataset is fundamental to studies of clastic strata and also to understanding of crustal evolution in the Eastern Mediterranean region. [ABSTRACT FROM AUTHOR]

A new 18O stable water isotope scheme is developed for three components of the iLOVECLIM coupled climate model: atmospheric, oceanic and land surface. The equations required to reproduce the fractionation of stable water isotopes in the simplified atmospheric model ECBilt are developed consistently with the moisture scheme. Simplifications in the processes are made to account for the simplified vertical structure including only one moist layer. Implementation of these equations together with a passive tracer scheme for the ocean and a equilibrium fractionation scheme for the land surface leads to the closure of the (isotopic-)water budget in our climate system. Fol lowing the implementation, verification of the existence of usual δ18O to climatic relationships are performed for the Rayleigh distillation, the Dansgaard relationship and the δ18O-salinity relationship. Advantages and caveats of the approach taken are outlined. [ABSTRACT FROM AUTHOR]

Oceans are a net source of molecular hydrogen (H2) to the atmosphere, where nitrogen (N2) fixation is assumed to be the main biological production pathway besides photo-chemical production from organic material. The sources can be distinguished using isotope measurements because of clearly differing isotopic signatures of the produced hydrogen. Here we present the first ship-borne measurements of atmospheric molecular H2 mixing ratio and isotopic composition at the West African coast of Mauritania (16-25° W, 17-24° N). This area is one of the biologically most active regions of the world's oceans with seasonal upwelling events and characterized by strongly differing hydro-graphical/biological properties and phytoplankton community structures. The aim of this study was to identify areas of H2 production and distinguish H2 sources by isotopic signatures of atmospheric H2. Besides this a diurnal cycle of atmospheric H2 was investigated. For this more than 100 air samples were taken during two cruises in February 2007 and 2008, respectively. During both cruises a transect from the Cape Verde Island towards the Mauritanian Coast was sampled. In 2007 additionally four days were sampled with a high resolution of one sample per hour. Our results clearly indicate the influence of local sources and suggest the Banc d'Arguin as a pool for precursors for photochemical H2 production, whereas N2 fixation could not be identified as a H2 source during these two cruises. With our experimental setup we could demonstrate that variability in diurnal cycles is probably influenced and biased by released precursors for photochemical H2 production and the origin of air masses. This means for further investigations that just measuring the mixing ratio of H2 is insufficient to explain the variability of a diurnal cycle and support is needed, e.g. by isotopic measurements. However, measurements of H2 mixing ratios, which are easy to conduct online during ship cruises could be a helpful tool to easily identify production areas of biological precursors such as VOC's for further investigations. [ABSTRACT FROM AUTHOR]

The article discusses a study which presents results of a newly developed isotope scheme within the ECHAM5-JSBACH model, which has been developed by combining two separate components, the atmosphere model ECHAM5 and the land surface scheme "Jena Scheme for Biosphere-Atmosphere Interaction in Hamburg" (JSBACH). It is noted that ECHAM5 is an Atmosphere General Circulation Model (AGCM)and JSBACH model calculates terrestrial boundary conditions for ECHAM5 over the land surface.

The article presents a study which uses laser spectroscopy to measure variations of isotopes in atmospheric water vapour. The study compares two laser spectroscopic systems which are based on cavity ring-down spectroscopy and off-axis integrated cavity output spectroscopy. It looks into uncertain components of continuous measurements including effects of water vapour mixing ratio and measurement stability.

Mathematical techniques for modeling and simulating dangerous or complex systems, such as nuclear technology systems, often require high-performance computing to process and analyze available data. In this paper, simple and quick method to support studies and research related to nuclear fuel is presented. This reasonably simple method helps to predict different concentrations of actinides and fission products in nuclear fuels without the need for expensive specialized programs and highly-trained researchers. The great importance of this approach is the speed of predicting the components of nuclear fuel concentrations, which in turn leads to quick decision-making, such as the possibility of operating fuel at higher burnup values, predicting the amount of gases resulting from nuclear fission (which may accumulate and cause problems in nuclear fuel such as volume swells), and other important decisions in nuclear fuel technology. The predicted equations have been generalized for higher values of burnup and compared with comparable results from MCNP codes. The equations deduced in calculating the different concentrations of xenon and krypton isotopes resulting from fission in burnup of nuclear fuel showed very precise results with discrepancies (magnitude of an error between the data points and the corresponding predicted ones) less than 2%. The suggested method offers a great advantage for researchers, which are the use one of any simple or common computational programs available to most researchers and do not need much experience to deal with, such as MATLAB, Excel that are easy to use for regression analyses. In this paper, the advantages of the proposed method are explained along with the limitations of its use. [ABSTRACT FROM AUTHOR]

With the recent advent of commercial laser absorption spectrometers, field studies measuring stable isotope ratios of hydrogen and oxygen in water vapor have proliferated. These pioneering analyses have provided invaluable feedback about best strategies for optimizing instrumental accuracy, yet questions still remain about instrument performance and calibration approaches for multi-year field deployments. With clear scientific potential for using these instruments to carry out long-term monitoring of the hydrological cycle, this study examines the long-term stability of the isotopic biases associated with three cavity-enhanced laser absorption spectrometers - calibrated with different systems and approaches - at two remote field sites: Mauna Loa Observatory, Hawaii, USA, and Greenland Environmental Observatory, Summit, Greenland. The analysis pays particular attention to the stability of measurement dependencies on water vapor concentration and also evaluates whether these so-called concentrationdependences are sensitive to statistical curve-fitting choices or measurement hysteresis. The results suggest evidence of monthly-to-seasonal concentration-dependence variability - which likely stems from low signal-to-noise at the humidity-range extremes - but no long-term directional drift. At Mauna Loa, where the isotopic analyzer is calibrated by injection of liquid water standards into a vaporizer, the largest source of inaccuracy in characterizing the concentration-dependence stems from an insucient density of calibration points at low humidity. In comparison, at Greenland, the largest source of inaccuracy is measurement hysteresis associated with interactions between the reference vapor, generated by a custom dew point generator (DPG), and the sample tubing. Nevertheless, prediction errors associated with correcting the concentration-dependence are small compared to total measurement uncertainty. At both sites, a dominant source of uncertainty is instrumental precision at low humidity, which cannot be reduced by improving calibration strategies. Challenges in monitoring long-term isotopic drift are also discussed in light of the different calibration systems evaluated. [ABSTRACT FROM AUTHOR]

Air bubbles in ice core samples represent the only opportunity to study the isotopic variability of paleoatmospheric CH4 and N2O. The highest possible precision in isotope measurements is required to maximize the resolving power for CH4 and N2O sink and source reconstructions. We present a new setup to measure δ13C-CH4, δ15N-N2O and δ18O-N2O isotope ratios in one ice core sample, with a precision of 0.09 ‰, 0.6 ‰ and 0.7 ‰, respectively, as determined on 0.6-1.6 nmol CH4 and 0.25-0.6 nmol N2O. The isotope ratios are referenced to the VPDB scale (δ13C-CH4), the N2-air scale (δ15N-N2O) and the VSMOW scale (δ18O-N2O). Ice core samples of 200-500 g are melted while the air is constantly extracted to minimize gas dissolution. A helium carrier gas flow transports the sample through the analytical system. A gold catalyst is used to oxidize CO to CO2 in the air sample without affecting the CH4 and N2O sample. CH4 and N2O are then separated from N2, O2, Ar and CO2 before they get pre-concentrated and separated by gas chromatography. While the separated N2O sample is immediately analysed in the mass spectrometer, a combustion unit is required for δ13C-CH4 analysis, which is equipped with a constant oxygen supply as well as a post-combustion trap and a post-combustion GC-column (GC-C-GC-IRMS). The post combustion trap and the second GC column in the GC-C-GC-IRMS combination increase the time for δ13C-CH4 analysis which is used to measure δ15N-N2O and δ18O-N2O first and then δ13C-CH4. The analytical time is adjusted to ensure stable conditions in the ion-source before each sample gas enters the IRMS, thereby improving the precision achieved for measurements of CH4 and N2O on the same IRMS. After the extraction of the air from the ice core sample, the analysis of CH4 and N2O takes 42 min. The setup is calibrated by analyzing multiple isotope reference gases that were injected over bubble-free-ice samples. We show a comparison of ice core sample measurements for δ13C-CH4 that are of excellent reproducibility and accuracy, and in good agreement with previously published data. [ABSTRACT FROM AUTHOR]

Molecular lipid biomarkers (hydrocarbons, alcohols, sterols and fatty acids) and compound specific isotope analysis of suspended particulate organic matter (SPM) and surface sediments of the Mackenzie Shelf and slope (Southeast Beaufort Sea, Arctic Ocean), were studied in summer 2009. The concentrations of the molecular lipid markers, characteristic of known organic matter sources, were grouped and used as proxies to evaluate the relative importance of fresh algal, detrital algal, fossil, C3terrestrial plants, bacterial and zooplankton material in the sedimentary organic matter (OM). Fossil and detrital algal contributions were the major fractions of the freshwater SPM from the Mackenzie River with ~34% each of the total molecular biomarkers. Fresh algal, C3terrestrial, bacterial and zooplanktonic components represented much lower percentages, 17, 10, 4 and <1 %, respectively. In marine SPM from the Mackenzie slope, the major contributions were fresh and detrital algal components (>80 %) with a minor contribution of fossil and C3terrestrial biomarkers. Characterization of the sediments revealed a major sink of refractory algal material mixed with some fresh algal material, fossil hydrocarbons and a small input of C3terrestrial sources. In particular, the sediments from the shelf and at the mouth of the Amundsen Gulf presented the highest contribution of detrital algal material (60-75 %) whereas those from the slope contained the highest proportion of fossil (40 %) and C3terrestrial plant material (10 %). Overall, considering that the detrital algal material is marine derived, autochthonous sources contributed more than allochthonous sources to the OM lipid pool. Using the ratio of an allochthonous biomarker (normalized to total organic carbon, TOC) found in the sediments to those measured at the river mouth water, we estimated that the fraction of terrestrial material preserved in the sediments accounted for 30-40% of the total carbon in the inner shelf sediments, 17% in the outer shelf and Amundsen Gulf and up to 25% in the slope sediments. [ABSTRACT FROM AUTHOR]

Despite practical complexities, isotope tracing studies in humans are becoming increasingly feasible. However, several technological challenges need to be addressed in order to take full advantage of human tracing studies. First, absolute metabolic flux measurements in mice are not so easily applied to human models, given that tissue resection is restricted to a single surgical time point. Second, isotope tracing has yet to be employed to detect metabolic differences between cells types in vivo. Here, we discuss the current models and propose an alternative, liquid tumor environment, that could overcome these limitations. Furthermore, we highlight current strategies used to maintain isotopolog enrichment following cell isolation techniques to facilitate cell-type-specific analysis., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The article presents a study which evaluates a flask air sampling system for atmospheric trace gas observation on a cargo C-130H aircraft from he Japan Meteorological Agency (JMA). The study uses quality assurance laboratory test of the flask sampling air. Results show relatively high reproducibility of all laboratory tests and no significant influence of isotope effects for the laser-based analyzers.

The article presents a study which investigates the production of isotope reference gases for methane in synthetic air. It is inferred that an isotope reference gas is essential in the quantitative estimation of changes in the biochemistry of methane. The combustion of pure methane gases from fossil and biogenic sources is described.