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2. Reply to Comment on Our Paper "Comparison of Isotope Pairing and N 2 : Ar Methods for Measuring Sediment Denitrification"
- Author
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Eyre, Bradley D., Rysgaard, Søren, Dalsgaard, Tage, and Christensen, Peter Bondo
- Published
- 2004
3. FOREST-FLOOR NITROGEN DYNAMICS IN A 60-YEAR-OLD PAPER BIRCH ECOSYSTEM IN INTERIOR ALASKA
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VAN CLEVE, KEITH and WHITE, ROBERT
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- 1980
4. Comments on a paper entitled: Toxicity and carcinogenicity of plutonium-239
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Pigg, C
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- 1978
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- View/download PDF
5. The analysis of low level gamma-ray activity by scintillation spectrometry
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Humphreys, D.
- Published
- 2020
6. A REVIEW OF SOME SCIENTIFIC PAPERS BY PROF. STANISŁAW SZPIKOWSKI.
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Góźdź, Andrzej
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PHYSICS research , *THERMOPHORESIS , *ISOTOPES , *NONEQUILIBRIUM thermodynamics - Abstract
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]
- Published
- 2015
7. Integrating buccal and occlusal dental microwear with isotope analyses for a complete paleodietary reconstruction of Holocene populations from Hungary.
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Hernando R, Gamarra B, McCall A, Cheronet O, Fernandes D, Sirak K, Schmidt R, Lozano M, Szeniczey T, Hajdu T, Bárány A, Kalli A, Tutkovics EK, Köhler K, Kiss K, Koós J, Csengeri P, Király Á, Horváth A, Hajdu ML, Tóth K, Patay R, Feeney RNM, and Pinhasi R
- Subjects
- Carbon Isotopes analysis, Humans, Hungary, Tooth chemistry, Cheek pathology, Fossils, Isotopes analysis, Tooth pathology
- Abstract
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 δ15 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 δ13 C and δ15 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 C4 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.- Published
- 2021
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8. The discoveries of uranium 237 and symmetric fission - from the archival papers of Nishina and Kimura
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Nagao Ikeda
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uranium 237 ,Isotope ,Isotopes of uranium ,Fission ,Chemistry ,Archives ,Thorium ,neptunium ,General Physics and Astronomy ,chemistry.chemical_element ,General Medicine ,Review ,Uranium ,History, 20th Century ,Neutron temperature ,Nuclear physics ,uranium ,Actinium ,symmetric fission ,Isotopes ,Nuclear fission ,fast neutron ,Nuclide ,General Agricultural and Biological Sciences ,Nuclear Fission - Abstract
Shortly before the Second World War time, Nishina reported on a series of prominent nuclear physical and radiochemical studies in collaboration with Kimura. They artificially produced (231)Th, a member of the natural actinium series of nuclides, by bombarding thorium with fast neutrons. This resulted in the discovery of (237)U, a new isotope of uranium, by bombarding uranium with fast neutrons, and confirmed that (237)U disintegrates into element 93 with a mass number of 237. They also identified the isotopes of several middle-weighted elements produced by the symmetric fission of uranium. In this review article, the highlights of their work are briefly summarized along with some explanatory commentaries.
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- 2011
9. Reciprocal Transfer of Carbon Isotopes between Ectomycorrhizal Betula papyrifera and Pseudotsuga menziesii
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Simard, Suzanne W., Jones, Melanie D., Durall, Daniel M., Perry, David A., Myrold, David D., and Molina, Randy
- Published
- 1997
10. Isotopes as Tracers in Marine Environmental Studies – A Forthcoming Collection of Papers in the Isotopesin the EnvironmentDomain
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Pavel P. Povinec
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Article Subject ,radiometrics ,Environmental change ,lcsh:Medicine ,lcsh:Technology ,General Biochemistry, Genetics and Molecular Biology ,Domain (software engineering) ,modelling ,dating methods ,accelerator mass spectrometry ,lcsh:Science ,isotopes ,database ,seawater ,General Environmental Science ,lcsh:T ,lcsh:R ,environmental change ,General Medicine ,Environmental studies ,Editorial ,Oceanography ,sediment ,Environmental science ,lcsh:Q ,Computer modelling - Abstract
TheScientificWorldJOURNAL and the Isotopes in the Environment Domain announce the forthcoming publication of peer-reviewed papers on Isotopes as Tracers in Marine Environmental Studies, a session held at the 2001: An Ocean Odyssey Conference on 2128 October 2001, Mar Del Plata, Argentina. The conference provided an opportunity to explore both radioactive and stable isotopes as tracers in studies of oceanographic processes, behaviour of radionuclides in the water column, water and sediment dynamics, marine environmental change, and computer modelling of dispersion of isotopes in the marine environment. The Guest Editor for the collection is Pavel Povinec and we expect publication of around 15 papers to be completed by March 2002. Each paper will be promoted to all relevant Domains of TheScientificWorldJOURNAL an interdisciplinary approach much in line with the general objectives of the conference. Readers are invited to check back regularly to the Table of
- Published
- 2002
11. Two-dimensional paper chromatography of radioactive substances
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F. P. W. Winteringham
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Solvent system ,Paper ,Paper chromatography ,Chromatography ,Multidisciplinary ,Isotopes ,Chemistry ,law ,Chromatography, Paper ,STRIPS ,law.invention - Abstract
AN automatic scanning technique employing a Geiger–Muller tube for the location and estimation of radioactive substances separated on unidimensional paper chromatograms has been described1. The application of this technique to two-dimensional chromatograms is tedious because a large sheet of paper has first to be cut up into the equivalent number of unidimensional strips and each strip scanned separately. To obviate this difficulty, an alternative technique to the conventional form of two-dimensional paper chromatography has been successfully developed for the application of two or more solvent systems to the same labelled mixture.
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- 1953
12. The Use of Environmental Isotopes in Hydrogeology.
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Carreira, Paula M. and Marques, José M.
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GROUNDWATER recharge ,SCIENTIFIC knowledge ,ISOTOPES ,AQUIFERS ,HYDROGEOLOGY ,WATER management ,MACHINE learning ,ENVIRONMENTAL sciences - Abstract
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]
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- 2024
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13. The enzyme mechanism of patchoulol synthase
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Houchao Xu, Bernd Goldfuss, Gregor Schnakenburg, and Jeroen S Dickschat
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Chemistry ,enzyme mechanisms ,QD241-441 ,Science ,Organic chemistry ,biosynthesis ,Full Research Paper ,dft calculations ,isotopes ,terpenes - Abstract
Different mechanisms for the cyclisation of farnesyl pyrophosphate to patchoulol by the patchoulol synthase are discussed in the literature. They are based on isotopic labelling experiments, but the results from these experiments are contradictory. The present work reports on a reinvestigation of patchoulol biosynthesis by isotopic labelling experiments and computational chemistry. The results are in favour of a pathway through the neutral intermediates germacrene A and α-bulnesene that are both reactivated by protonation for further cyclisation steps, while previously discussed intra- and intermolecular hydrogen transfers are not supported. Furthermore, the isolation of the new natural product (2S,3S,7S,10R)-guaia-1,11-dien-10-ol from patchouli oil is reported.
- Published
- 2022
14. δ18O water isotope in the iLOVECLIM model (version 1.0) - Part 2: Evaluation of model results against observed δ18O in water samples.
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Roche, D. M. and Caley, T.
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ISOTOPES ,WATER sampling ,ATMOSPHERIC models ,SPATIAL distribution (Quantum optics) ,RAYLEIGH model - Abstract
The H
2 18 O 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 δ18 O 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]- Published
- 2013
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15. Galectin–Glycan Interactions: Guidelines for Monitoring by77Se NMR Spectroscopy, and Solvent (H2O/D2O) Impact on Binding
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Francisco J. Medrano, Mare Cudic, Hans-Joachim Gabius, Mark Reihill, Antonio A. Romero, Forrest G FitzGerald, Tammo Diercks, Donella Beckwith, Stefan Oscarson, Martin Jaeger Pedersen, Anna-Kristin Ludwig, Ministerio de Economía y Competitividad (España), Eusko Jaurlaritza, Science Foundation Ireland, National Institutes of Health (US), Diercks, Tammo, Medrano, Francisco Javier, FitzGerald, Forrest G., Beckwith, Donella, Martin Jaeger Pedersen, Reihill, Mark, Ludwig, Anna-Kristin, Romero, Antonio, Oscarson, Stefan, Cudic, Mare, Gabius, Hans-Joachim, Diercks, Tammo [0000-0002-5200-0905], Medrano, Francisco Javier [0000-0002-8185-9751], FitzGerald, Forrest G. [0000-0003-3568-6543], Beckwith, Donella [0000-0002-2124-4931], Martin Jaeger Pedersen [0000-0003-3223-3661], Reihill, Mark [0000-0003-3896-9346], Ludwig, Anna-Kristin [0000-0002-0935-9410], Romero, Antonio [0000-0002-6990-6973], Oscarson, Stefan [0000-0002-8273-4918], Cudic, Mare [0000-0002-7657-0400], and Gabius, Hans-Joachim [0000-0003-3467-3900]
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Glycan ,Circular dichroism ,Galectins ,Calorimetry ,Ligands ,010402 general chemistry ,01 natural sciences ,Catalysis ,Selenium ,Selenoglycosides | Hot Paper ,Isotopes ,Polysaccharides ,Selenoglycosides ,Humans ,Deuterium Oxide ,Nuclear Magnetic Resonance, Biomolecular ,Galectin ,Binding Sites ,Full Paper ,biology ,010405 organic chemistry ,Chemistry ,Organic Chemistry ,77Se NMR ,General Chemistry ,Guideline ,Nuclear magnetic resonance spectroscopy ,Full Papers ,0104 chemical sciences ,Solvent ,Crystallography ,77Se NMR spectroscopy ,Solvents ,biology.protein ,Protein Binding - Abstract
10 p.-6 fig.-3 tb., Functional pairing between cellular glyco-con-ju-gates and tissue lectins like galectins has wide (patho)physio-logical significance. Their study is facilitated by non-hydrolyzable deri-va-tives of the natural O-glycans, such as S- and Se-glycosides. The latter en-able extensive analyses by specific 77 Se NMR spectroscopy, but still remain under-explored. By the example of seleno--digalac-to-side (SeDG) and the human galectins 1 and 3, we evaluate diverse 77 Se NMR detec-tion methods and pro-pose selec-tive 1 H, 77 Se hetero-nuclear Hartmann-Hahn transfer for efficient use in com-peti-tive NMR screening against a seleno-glycoside spy ligand. By fluores-cence aniso-tropy, circular dichroism, and isothermal titra-tion calori-metry (ITC) we show that affinity and thermodynamics of SeDG bind-ing by galectins are similar to thiodi-galac-toside (TDG) and N-acetyl-lactos-amine (LacNAc), con-firm-ing that Se substitution has no major impact. ITC data in D 2 O vs. H 2 O are similar for TDG and LacNAc binding by both galectins, but a solvent effect, indicating solvent rearrangement at the binding site, is hinted for SeDG and clearly observed for LacNAc dimers with extend-ed chain length., We are much indebted to L. Szilágyi (University of Debrecen,Hungary) for kindly providing selenoglycosides for this study. We are grateful for inspiring discussions to Drs. B. Friday, A. Leddoz and A. W. L. Nose as well as for generous funding from the Spanish Ministry of Economy and Competitiveness (grant BFU2016-77835-R; to A.R.), the Department of Industry, Tourism and Trade of the Government of the Autonomous Community of the Basque Country (Elkartek BG2019; to T.D.), the Severo Ochoa Excellence Accreditation from MCIU (SEV-2016-0644; to T.D.), the Science Foundation of Ireland (grants 13/IA/1959 and 16/RC/3889;to S.O.), National Institute of Health (NIH) grant CA242351 to M.Cudic, and the COST Action CA 18103 (InnoGly; to H.-J.G.).
- Published
- 2020
16. Cu isotope fractionation between Cu-bearing phases and hydrothermal fluids: Insights from ex situ and in situ experiments.
- Author
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Qi, Dongmei, Zhang, Chao, and Lazarov, Marina
- Abstract
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 (Δ
65 Cufluid-mineral ): (1) associated with Cu(I) dissolution, Cu(I) disproportionation as well as oxidation of Cu(0) (native copper) and Cu(I) in Cu ± Cu2 O + 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 Cu2 O + NaCl + 0.2 m HAc/NaAc (pH-buffer), and runs were conducted at 200–250 °C and 20 MPa. Δ65 Cufluid-mineral shows the least variation during solid separation from source fluids, generally <0.16 ± 0.03‰. Positive Δ65 Cufluid-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 Δ65 CuCu(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 of65 Cu 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 Δ65 CuCu(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 (63 Cu) 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 Δ65 Cufluid-Cu up to 0.59 ± 0.03‰ and Δ2 O65 CuCu(0)-Cu up to –0.28 ± 0.02‰. Rapid cooling (3–25 K s2 O–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]- Published
- 2024
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17. Functional Switch and Ethyl Group Formation in the Bacterial Polytrichastrene Synthase from Chryseobacterium polytrichastri
- Author
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Jeroen S. Dickschat, Bernd Goldfuss, and Anwei Hou
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Stereochemistry ,Molecular Conformation ,Catalysis ,Terpene ,Isotopic labeling ,chemistry.chemical_compound ,enzyme mechanisms ,Polyisoprenyl Phosphates ,Biosynthesis ,Ethyl group ,isotopes ,Density Functional Theory ,Hydro-Lyases ,Chryseobacterium ,biology ,ATP synthase ,Communication ,Active site ,General Chemistry ,Communications ,Biosynthesis | Hot Paper ,chemistry ,biology.protein ,biosynthesis ,Diterpene ,Chryseobacterium polytrichastri ,mutagenesis ,terpenes - Abstract
A reinvestigation of the linalool synthase from Chryseobacterium polytrichastri uncovered its diterpene synthase activity, yielding polytrichastrene A and polytrichastrol A with new skeletons, besides known wanju‐2,5‐diene and thunbergol. The enzyme mechanism was investigated by isotopic labeling experiments and DFT calculations to explain an unusual ethyl group formation. Rationally designed exchanges of active site residues showed major functional switches, resulting for I66F in the production of five more new compounds, including polytrichastrene B and polytrichastrol B, while A87T, A192V and the double exchange A87T, A192V gave a product shift towards wanju‐2,5‐diene., Linalool synthase from Chryseobacterium polytrichastri was found to have diterpene synthase activity and produced diterpenes with new skeletons containing a rare ethyl group. Its formation was mechanistically studied through isotopic labeling and DFT calculations. Exchange of active site residues resulted in a functional switch leading to additional novel diterpenes. This work lays the ground for future rational engineering of terpene synthases.
- Published
- 2021
18. Isotope pattern deconvolution as a successful alternative to calibration curve for application in wastewater-based epidemiology
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Lubertus Bijlsma, Juan Vicente Sancho Llopis, Jorge Pitarch-Motellón, and A.F. Roig-Navarro
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Calibration (statistics) ,Calibration curve ,02 engineering and technology ,Wastewater ,Isotope dilution ,01 natural sciences ,Biochemistry ,Analytical Chemistry ,Isotopes ,Limit of Detection ,Statistics ,Humans ,Illicit drug ,Isotope pattern deconvolution ,Mathematics ,Combined uncertainty ,Mass spectrometry ,Isotope ,Illicit Drugs ,Wastewater analysis ,010401 analytical chemistry ,Reproducibility of Results ,Wastewater based epidemiology ,Reference Standards ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Substance Abuse Detection ,Calibration ,Deconvolution ,0210 nano-technology ,Water Pollutants, Chemical ,Research Paper - Abstract
Graphical abstract An isotope pattern deconvolution (IPD) quantification method has been applied for the determination of five substances (amphetamine, benzoylecgonine, cocaine, methamphetamine and MDMA) in wastewater for the application in wastewater-based epidemiology (WBE). A previously validated method that used a calibration curve for quantification was modified to apply IPD. The two approaches were compared in terms of analytical uncertainty in recovery studies of quality control samples, i.e. six wastewater samples from different geographical origins spiked at two concentration levels. Both methods were reliable as they passed (z-score
- Published
- 2021
19. Identification of volatiles from six marine Celeribacter strains
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Dorota Konvalinkova, Anuj Kumar Chhalodia, Jeroen S. Dickschat, Jan Rinkel, and Jörn Petersen
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Stereochemistry ,Sulfur metabolism ,chemistry.chemical_element ,gc–ms ,010402 general chemistry ,01 natural sciences ,Full Research Paper ,lcsh:QD241-441 ,chemistry.chemical_compound ,lcsh:Organic chemistry ,Moiety ,lcsh:Science ,Rhodobacteraceae ,isotopes ,Methionine ,biology ,010405 organic chemistry ,Organic Chemistry ,Roseobacter ,biology.organism_classification ,Sulfur ,0104 chemical sciences ,Chemistry ,volatiles ,Benzothiazole ,chemistry ,sulfur metabolism ,lcsh:Q ,roseobacter ,Dimethyl trisulfide - Abstract
The volatiles emitted from six marine Rhodobacteraceae species of the genus Celeribacter were investigated by GC–MS. Besides several known compounds including dimethyl trisulfide and S-methyl methanethiosulfonate, the sulfur-containing compounds ethyl (E)-3-(methylsulfanyl)acrylate and 2-(methyldisulfanyl)benzothiazole were identified and their structures were verified by synthesis. Feeding experiments with [methyl-2H3]methionine, [methyl-13C]methionine and [34S]-3-(dimethylsulfonio)propanoate (DMSP) resulted in the high incorporation into dimethyl trisulfide and S-methyl methanethiosulfonate, and revealed the origin of the methylsulfanyl group of 2-(methyldisulfanyl)benzothiazole from methionine or DMSP, while the biosynthetic origin of the benzothiazol-2-ylsulfanyl portion could not be traced. The heterocyclic moiety of this compound is likely of anthropogenic origin, because 2-mercaptobenzothiazole is used in the sulfur vulcanization of rubber. Also in none of the feeding experiments incorporation into ethyl (E)-3-(methylsulfanyl)acrylate could be observed, questioning its bacterial origin. Our results demonstrate that the Celeribacter strains are capable of methionine and DMSP degradation to widespread sulfur volatiles, but the analysis of trace compounds in natural samples must be taken with care.
- Published
- 2021
20. Evaluation of continuous water vapor δD and δ18O measurements by off-axis integrated cavity output spectroscopy.
- Author
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Kurita, N., Newman, B. D., Araguas-Araguas, L. J., and Aggarwal, P.
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ATMOSPHERIC water vapor ,ISOTOPES ,SPECTRUM analysis ,SPECTROPHOTOMETRY ,ANALYTICAL chemistry - Abstract
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.
- Published
- 2012
- Full Text
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21. Review papers in Journal of Materials Science Volumes 37, 38 and 39.
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MATERIALS science , *PERIODICALS , *CARBON , *NANOSTRUCTURED materials , *ISOTOPES , *SOLIDS - Abstract
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.
- Published
- 2004
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22. Carbonate "clumped" isotope signatures in aragonitic scleractinian and calcitic gorgonian deep-sea corals.
- Author
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Kimball, J., Tripati, R. E., and Dunbar, R.
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CARBONATES ,SCLERACTINIA ,ALCYONACEA ,ISOTOPES ,ATMOSPHERIC temperature ,METEOROLOGICAL precipitation - Abstract
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
13 C18 O16 O2 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]- Published
- 2015
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23. 湖相碳酸盐碳、氧同位素与团簇同位素的研究进展.
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李世恩 and 关平
- Subjects
CARBON isotopes ,OXYGEN isotopes ,ISOTOPES ,CARBONATES - Abstract
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.)
- Published
- 2023
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- View/download PDF
24. Time-Course Development of 14 C Specific Activity of Chlorophyll a, Carbon, and Proteins in Algal Cultures
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Riemann, Bo, Lignell, Risto, and Laws, Edward
- Published
- 1993
25. The added value of water isotopic measurements for understanding model biases in simulating the water cycle over Western Siberia.
- Author
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Gryazin, V., Risi, C., Jouzel, J., Kurita, N., Worden, J., Frankenberg, C., Bastrikov, V., Gribanov, K., and Stukova, O.
- Subjects
METEOROLOGICAL precipitation ,ATMOSPHERIC water vapor ,METEOROLOGICAL observations ,CLIMATE change ,ATMOSPHERIC models ,ISOTOPES ,COMPUTER simulation ,WATER bikes - Abstract
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]
- Published
- 2014
- Full Text
- View/download PDF
26. Multidisciplinary investigations of the diets of two post-medieval populations from London using stable isotopes and microdebris analysis
- Author
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Patrick Daley, Anita Radini, Madeleine Bleasdale, Luke Spindler, Lucy Sibun, Camilla Speller, Chloe Brown, Sean Doherty, Andrew Wilson, Paola Ponce, and Michelle Alexander
- Subjects
010506 paleontology ,Archeology ,Biology ,01 natural sciences ,Isotopes ,0601 history and archaeology ,0105 earth and related environmental sciences ,Original Paper ,Bone collagen ,Calculus ,060102 archaeology ,Light isotope ,Stable isotope ratio ,Dietary intake ,Post Medieval ,Marine fish ,06 humanities and the arts ,Post-medieval ,Diet ,Anthropology ,Collagen ,Social status ,Demography ,Hair - Abstract
This paper presents the first multi-tissue study of diet in post-medieval London using both the stable light isotope analysis of carbon and nitrogen and analysis of microdebris in dental calculus. Dietary intake was explored over short and long timescales. Bulk bone collagen was analysed from humans from the Queen’s Chapel of the Savoy (QCS) (n = 66) and the St Barnabas/St Mary Abbots (SB) (n = 25). Incremental dentine analysis was performed on the second molar of individual QCS1123 to explore childhood dietary intake. Bulk hair samples (n = 4) were sampled from adults from QCS, and dental calculus was analysed from four other individuals using microscopy. In addition, bone collagen from a total of 46 animals from QCS (n = 11) and the additional site of Prescot Street (n = 35) was analysed, providing the first animal dietary baseline for post-medieval London. Overall, isotopic results suggest a largely C3-based terrestrial diet for both populations, with the exception of QCS1123 who exhibited values consistent with the consumption of C4 food sources throughout childhood and adulthood. The differences exhibited in δ15Ncoll across both populations likely reflect variations in diet due to social class and occupation, with individuals from SB likely representing wealthier individuals consuming larger quantities of animal and marine fish protein. Microdebris analysis results were limited but indicate the consumption of domestic cereals. This paper demonstrates the utility of a multidisciplinary approach to investigate diet across long and short timescales to further our understanding of variations in social status and mobility. Electronic supplementary material The online version of this article (10.1007/s12520-019-00910-8) contains supplementary material, which is available to authorized users.
- Published
- 2019
27. Application of stable isotope dilution techniques to assess body fat and comparison with WHO BMI-for-age classification as a measure of obesity among schoolchildren in Nairobi, Kenya
- Author
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Dorcus Mbithe D. Kigaru, Catherine W Macharia-Mutie, and Zipporah W. Ndungu
- Subjects
Pediatric Obesity ,medicine.medical_specialty ,Wilcoxon signed-rank test ,Concordance ,Indicator Dilution Techniques ,Medicine (miscellaneous) ,Overweight ,Standard score ,World Health Organization ,Childhood obesity ,Body Mass Index ,Isotopes ,Environmental health ,Epidemiology ,medicine ,Humans ,Child ,Nutrition and Dietetics ,business.industry ,Public Health, Environmental and Occupational Health ,Anthropometry ,medicine.disease ,Kenya ,Obesity ,Cross-Sectional Studies ,Adipose Tissue ,Body Composition ,medicine.symptom ,business ,Research Paper - Abstract
Objective:WHO BMI-for-agezscore (BAZ) is widely used in epidemiology, yet it does not distinguish body fat-free mass and fat mass which are better indicators of obesity and related risks. The stable isotope dilution techniques (SIDT) are gold standard methods of assessing body composition. Main objective was to assess significant differences in measurement and validity of WHO BMI-for-age classification for defining childhood obesity by comparing with body fatness using SIDT among schoolchildren.Design:A cross-sectional analytical study. A questionnaire, anthropometry and body composition data were used. SPSS was used to analyse data atP< 0·05 at 95 % CI.Setting:Primary schools in Nairobi City County, KenyaParticipants:One hundred seventy-nine schoolchildren aged 8–11 years were randomly sampled.Results:Prevalence of adiposity by reference SIDT (24·0 %) was significantly higher than that of obesity by BAZ > 2sd(2·8 %) (Wilcoxon test,P< 0·05). Concordance coefficient between SIDT and BAZ > 2sdin diagnosing obesity was poor (κ= 0·167). Only 11·6 % of children with excess body fat were correctly diagnosed as obese by BAZ > 2sd. The use of BAZ > 1sdfor overweight and obesity showed fair concordance coefficient (κ= 0·409,P< 0·001) with 32·5% of children with excess fat positively identified as overweight and obese.Conclusion:WHO BMI-for-age cut-off points severely underestimate the prevalence of overweight and obesity compared with body composition assessment by stable isotope dilution techniques. Evidence-informed interventions should be based on more accurate estimates of overweight and obesity than that can be provided by BAZ.
- Published
- 2020
28. An attempt to improve the therapeutic effect of boron neutron capture therapy using commonly employed 10B-carriers based on analytical studies on the correlation among quiescent tumor cell characteristics, tumor heterogeneity and cancer stemness
- Author
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Hiroki Tanaka, Yoshinori Sakurai, Yu Sanada, Minoru Suzuki, Koji Ono, Takushi Takata, Shin-ichiro Masunaga, and Keizo Tano
- Subjects
cancer stemness ,Boron Compounds ,Lung Neoplasms ,Health, Toxicology and Mutagenesis ,Lung metastasis ,Cancer therapy ,Large capacity ,Apoptosis ,Boron Neutron Capture Therapy ,Tumor cells ,Borohydrides ,Ligands ,Tumor heterogeneity ,10B microdistribution ,030218 nuclear medicine & medical imaging ,Mice ,03 medical and health sciences ,0302 clinical medicine ,Isotopes ,Neoplasms ,tumor heterogeneity ,Regular Paper ,Tumor Microenvironment ,medicine ,Animals ,Humans ,Radiology, Nuclear Medicine and imaging ,Neoplasm Metastasis ,Cellular Senescence ,Boron ,Tumor microenvironment ,quiescent tumor cell ,Radiation ,business.industry ,Therapeutic effect ,Cancer ,medicine.disease ,Oxygen ,030220 oncology & carcinogenesis ,Neoplastic Stem Cells ,Cancer research ,AcademicSubjects/SCI00960 ,AcademicSubjects/MED00870 ,business ,Neoplasm Transplantation ,DNA Damage - Abstract
Based on our previously published reports concerning the response of quiescent (Q) tumor cell populations to boron neutron capture therapy (BNCT), the heterogeneous microdistribution of 10B in tumors, which is influenced by the tumor microenvironment and the characteristics of the 10B delivery carriers, has been shown to limit the therapeutic effect of BNCT on local tumors. It was also clarified that the characteristics of 10B-carriers for BNCT and the type of combined treatment in BNCT can also affect the potential for distant lung metastases from treated local tumors. We reviewed the findings concerning the response of Q tumor cell populations to BNCT, mainly focusing on reports we have published so far, and we identified the mode of BNCT that currently offers the best therapeutic gain from the viewpoint of both controlling local tumor and suppressing the potential for distant lung metastasis. In addition, based on the finding that oxygenated Q tumor cells showed a large capacity to recover from DNA damage after cancer therapy, the interrelationship among the characteristics in Q tumor cell populations, tumor heterogeneity and cancer stemness was also discussed.
- Published
- 2020
29. Current situation regarding lead exposure in birds in Japan (2015–2018); lead exposure is still occurring
- Author
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Yukiko Watanabe, Manabu Onuma, Chihiro Ishii, Keisuke Saito, Takeshi Kuritani, Yoshinori Ikenaka, Shouta M.M. Nakayama, Mitsuhiro Nakagawa, Mayumi Ishizuka, Kohei Ogasawara, Atsushi Haga, and 27878368 - Ikenaka, Yoshinori
- Subjects
Firearms ,Pb ammunition ,Endangered species ,Zoology ,Animals, Wild ,Toxicology ,water bird ,Birds ,Isotopes ,Japan ,biology.animal ,Animals ,Water bird ,Pb exposure ,General Veterinary ,biology ,Full Paper ,Haliaeetus albicilla ,Bird Diseases ,biology.organism_classification ,Raptor ,Lead Poisoning ,Lead ,Shot (pellet) ,raptor ,Lead exposure ,Environmental science ,Pb isotope ratios ,Haliaeetus pelagicus - Abstract
Birds of a number of species have died as a result of lead (Pb) poisoning, including many Steller's sea eagles (Haliaeetus pelagicus) and white-tailed sea eagles (Haliaeetus albicilla) in Hokkaido, the northernmost island of Japan. To address this issue, the use of any type of Pb ammunition for hunting of large animals was prohibited in Hokkaido in 2004. However, Pb poisoning is still being reported in this area, and there are few regulations regarding the use of Pb ammunition in other parts of Japan, where it has been reported that eagles and water birds have been exposed to Pb. This study was performed to accurately determine the current level of Pb exposure of birds found dead in the field or dead in the wild bird centers in Japan (June 2015-May 2018) and to identify the sources of Pb. Pb exposure was found to still be occurring in raptors and water birds in various parts of Japan. Twenty-six point five % and 5.9% of the recorded deaths of Steller's sea eagles and white-tailed sea eagles, respectively, were found to have been poisoned by Pb. In addition, Pb isotope ratio analysis showed that both Pb rifle bullets and Pb shot pellets cause Pb exposure in birds, and these endangered eagles are also exposed to Pb in Hokkaido due to the illegal use of Pb ammunition. Changing to Pb-free ammunition, such as copper (Cu) rifle bullets, steel shot pellets, or bismuth shot pellets, will be essential for the conservation of avian species in Japan.
- Published
- 2020
30. Perdeuterated Conjugated Polymers for Ultralow‐Frequency Magnetic Resonance of OLEDs
- Author
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Paul L. Burn, Sebastian Milster, Christoph Boehme, Hermann Kraus, John M. Lupton, Tobias Grünbaum, Sebastian Bange, Anna E. Leung, Dani M. Stoltzfus, Tamim A. Darwish, and Simon Kurrmann
- Subjects
Materials science ,Electron ,010402 general chemistry ,01 natural sciences ,Magnetic Resonance | Very Important Paper ,Catalysis ,magnetic resonance ,symbols.namesake ,conjugated polymers ,Hyperfine structure ,isotopes ,Spin-½ ,deuteration ,Larmor precession ,Zeeman effect ,010405 organic chemistry ,Communication ,Resonance ,Magnetoreception ,General Medicine ,General Chemistry ,organic light-emitting diodes ,Communications ,0104 chemical sciences ,Magnetic field ,symbols ,Atomic physics - Abstract
The formation of excitons in OLEDs is spin dependent and can be controlled by electron‐paramagnetic resonance, affecting device resistance and electroluminescence yield. We explore electrically detected magnetic resonance in the regime of very low magnetic fields (, Perdeuteration of a common OLED emitter allows the detection of paramagnetic resonances at field strengths comparable to Earth's. The competition between narrow resonance spectra and a quasistatic zero‐field feature resulting from reduced hyperfine coupling points at a low‐field limit for detecting paramagnetic resonances in radical‐pair‐based systems.
- Published
- 2020
31. A Family of Related Fungal and Bacterial Di‐ and Sesterterpenes: Studies on Fusaterpenol and Variediene
- Author
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Guangkai Bian, Jeroen S. Dickschat, Tiangang Liu, Rong Chen, Jan Rinkel, and Simon T. Steiner
- Subjects
Sesterterpenes ,Stereochemistry ,Prenyltransferase ,thermal rearrangement ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Terpene ,Fungal Proteins ,chemistry.chemical_compound ,Biosynthesis ,Very Important Paper ,Phosphofructokinase 2 ,Molecular Biology ,isotopes ,Alkyl and Aryl Transferases ,ATP synthase ,biology ,Bacteria ,Molecular Structure ,010405 organic chemistry ,Communication ,Organic Chemistry ,Enantioselective synthesis ,Absolute configuration ,Fungi ,Communications ,0104 chemical sciences ,absolute configuration ,Aspergillus ,chemistry ,biology.protein ,Molecular Medicine ,biosynthesis ,terpenes - Abstract
The absolute configuration of fusaterpenol (GJ1012E) has been revised by an enantioselective deuteration strategy. A bifunctional enzyme with a terpene synthase and a prenyltransferase domain from Aspergillus brasiliensis was characterised as variediene synthase, and the absolute configuration of its product was elucidated. The uniform absolute configurations of these and structurally related di‐ and sesterterpenes together with a common stereochemical course for the geminal methyl groups of GGPP unravel a similar conformational fold of the substrate in the active sites of the terpene synthases. For variediene, a thermal reaction observed during GC/MS analysis was studied in detail for which a surprising mechanism was uncovered., Absolute configuration of fusaterpenol (GJ1012E) revised: Variediene isolated from a newly characterised fungal diterpene synthase has a related absolute configuration. The comparison to other known diterpenes and labelling experiments point to a common substrate fold for a family of related compounds. A thermal reaction of variediene observed during GC/MS analysis is studied in detail.
- Published
- 2019
32. Correction: Fadil et al. Isotope Ratio Outlier Analysis (IROA) for HPLC–TOFMS-Based Metabolomics of Human Urine. Metabolites 2022, 12 , 741.
- Author
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Fadil, Fadi, Samol, Claudia, Berger, Raffaela S., Kellermeier, Fabian, Gronwald, Wolfram, Oefner, Peter J., and Dettmer, Katja
- Subjects
RATIO analysis ,CREATININE ,METABOLOMICS ,URINE ,METABOLITES ,ISOTOPES - Abstract
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]
- Published
- 2024
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33. Life histories in Fiji as reconstructed from first millennium CE Sigatoka Sand Dune burials using isotopes.
- Author
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Herrscher, Estelle, Valentin, Frédérique, Zinger, Wanda, Pradier, Baptiste, and André, Guy
- Subjects
RADIOCARBON dating ,SEXUAL division of labor ,SAND dunes ,DIETARY patterns ,NITROGEN isotopes ,ISOTOPES ,ISOTOPIC analysis - Abstract
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). δ
13 C and δ15 N ratios were measured on bone and tooth collagen samples from 38 adult individuals. The results show that δ15 N values from tooth are higher than those s from bone while bone and tooth δ13 C 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]- Published
- 2024
- Full Text
- View/download PDF
34. A synthesis of available detrital zircon data from Turkey, Cyprus and Greek peninsula.
- Author
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Chen, Guohui, Li, Chao, Shi, Yifan, and Zha, Kaijie
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ZIRCON ,PENINSULAS ,PUBLISHED articles ,SCIENCE publishing ,ISOTOPES - Abstract
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]
- Published
- 2024
- Full Text
- View/download PDF
35. δ18O water isotope in the iLOVECLIM model (version 1.0) - Part 1: Implementation and verification.
- Author
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Roche, D. M.
- Subjects
WATER research ,ISOTOPES ,ATMOSPHERIC models ,MOISTURE ,RAYLEIGH model - Abstract
A new
18 O 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 δ18 O to climatic relationships are performed for the Rayleigh distillation, the Dansgaard relationship and the δ18 O-salinity relationship. Advantages and caveats of the approach taken are outlined. [ABSTRACT FROM AUTHOR]- Published
- 2013
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- View/download PDF
36. High-resolution measurements of atmospheric molecular hydrogen and its isotopic composition at the West African coast of Mauritania.
- Author
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Walter, S., Kock, A., and Röckmann, T.
- Subjects
ATMOSPHERIC hydrogen ,ISOTOPES ,COASTS ,PHOTOCHEMISTRY ,NITROGEN fixation ,PHYTOPLANKTON ,CIRCADIAN rhythms - Abstract
Oceans are a net source of molecular hydrogen (H
2 ) 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]- Published
- 2012
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- View/download PDF
37. Stable water isotopes in the coupled atmosphere--land surface model ECHAM5-JSBACH.
- Author
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Haese, B., Werner, M., and Lohmann, G.
- Subjects
ATMOSPHERIC models ,CIRCULATION models ,MATHEMATICAL models ,ISOTOPES ,EARTH sciences - Abstract
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.
- Published
- 2012
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- View/download PDF
38. Measuring variations of δ18O and δ²H in atmospheric water vapour using laser spectroscopy: an instrument characterisation study.
- Author
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Aemisegger, F., Sturm, P., Graf, P., Sodemann, H., Pfahl, S., Knohl, A., and Wernli, H.
- Subjects
ATMOSPHERIC water vapor analysis ,ATMOSPHERIC water vapor measurement ,LASER spectroscopy ,ISOTOPES ,ATMOSPHERIC models ,SIMULATION methods & models - Abstract
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.
- Published
- 2012
- Full Text
- View/download PDF
39. Migration and cultural integration in the early medieval cemetery of Finglesham, Kent, through stable isotopes
- Author
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Sam Leggett and Apollo - University of Cambridge Repository
- Subjects
Mobility ,Archeology ,Original Paper ,Foodways ,Identity (social science) ,Community integration ,mobility ,Diet ,Geography ,Isotopes ,4301 Archaeology ,Early medieval ,Identity ,Anthropology ,Ethnology ,Narrative ,early medieval ,diet ,Kent ,4303 Historical Studies ,43 History, Heritage and Archaeology ,identity ,isotopes ,Social status - Abstract
Funder: Cambridge Philosophical Society; doi: http://dx.doi.org/10.13039/100013858, Debate over migrations to Britain during the fifth and sixth centuries AD is still rampant in archaeological discourse. Stable carbon, nitrogen and oxygen isotope values from multiple tissues in individuals buried at Finglesham in Kent during the first millennium AD demonstrate not only migration of individuals to the region but also highlight community integration through foodways and refute previous models of ‘invasion’ and replacement. This case study community suggests gendered differences in mobility into early medieval England, with males more likely to be migrants from cooler regions than women. It also challenges traditional narratives of social status in these furnished cemeteries being linked to diet or migrant status with no clear correlations found between funerary treatment and isotopic signatures. This multi-tissue and multi-isotope study tracks dietary changes in this multi-origin community throughout their lives and shows that they may have even changed their diets to adapt to Christianising influences in the region.
- Published
- 2021
40. Accurate prediction of gaseous isotopes Xe and Kr concentrations from the burnup of nuclear fuel using simple regression algorithm.
- Author
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Nafee, Sherif S., Al-Ramady, Amir M., Mohamed, Nader M., and Alshammari, Manal F.
- Subjects
NUCLEAR fission ,XENON isotopes ,KRYPTON ,ISOTOPES ,ACTINIDE elements ,NUCLEAR research ,NUCLEAR fuels - Abstract
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]
- Published
- 2023
- Full Text
- View/download PDF
41. Exposure assessment for the abandoned metal mine area contaminated by arsenic
- Author
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Seung Do Yu, Jun Young Chang, Seung Chul Ahn, Jung Sub Lee, Jong-Woo Choi, A-Ra Jung, Jaeseon Park, and Jee-Young Kim
- Subjects
Male ,Geologic Sediments ,010504 meteorology & atmospheric sciences ,Fresh Water ,010501 environmental sciences ,01 natural sciences ,Arsenicals ,chemistry.chemical_compound ,Isotopes ,Surveys and Questionnaires ,Environmental monitoring ,Soil Pollutants ,General Environmental Science ,Water Science and Technology ,media_common ,Agriculture ,General Medicine ,Middle Aged ,Environmental chemistry ,Female ,Environmental Monitoring ,Pollution ,Adult ,Environmental Engineering ,Soil test ,media_common.quotation_subject ,chemistry.chemical_element ,Stable Pb isotope ratio ,Mining ,Arsenic ,Abandoned metal mine ,Rivers ,Geochemistry and Petrology ,Water Supply ,Republic of Korea ,Environmental Chemistry ,Humans ,0105 earth and related environmental sciences ,Exposure assessment ,Aged ,Original Paper ,Sediment ,Environmental Exposure ,chemistry ,Lead ,Socioeconomic Factors ,Health effect ,Environmental science ,Arsenobetaine ,Water Pollutants, Chemical - Abstract
Among the results of community health impact assessments completed in 2014, residents of the Indae abandoned metal mine area showed high average urinary concentrations of harmful arsenic (As), at 148.9 µg/L. The concentration of harmful As was derived as the sum of As(V), As(III), MMA, and DMA concentrations known to be toxic. In this area, mining hazard prevention work was not carried out and the pollution source was neglected, and the health effect of the residents due to arsenic exposure was concerned. We re-assessed As exposure levels and tried to identify exposure factors for residents of this area. Analysis of the soil, sediment, and river water to assess the association between the soil of the Indae abandoned metal mine area and the soil in residential areas confirmed a correlation between Pb and As concentrations in the soil. Since Pb and As behave similarly, the use of the stable Pb isotope ratio for assessment of the pollution source tracking was validated. In the 3-isotope plot (207/206Pb vs. 208/206Pb) of soil samples in this area, a stable Pb isotope ratio was located on the same trend line, which confirmed that the soil in the residential area was within the area of influence of the Indae abandoned metal mine. Therefore, we judged that the pollution source of As was the Indae abandoned metal mine. The results by As species were As (III) 1.45 μg/L, As (V) 0.74 μg/L, monomethylarsonic acid (MMA) 2.43 μg/L, dimethylarsinic acid (DMA) 27.63 μg/L, and arsenobetaine 88.62 μg/L. The urinary harmful As was 31.92 μg/L, much lower than the 148.9 μg/L reported in a 2014 survey, due to the implementation of a multi-regional water supply in November 2014 that restricted As exposure through drinking river water. However, concerns remain over chronic exposure to As because As in river water used for farming and in agricultural soil still exceeds environmental standards; thus, ongoing work to address hazards from former mining areas and continued environmental monitoring is necessary.
- Published
- 2019
42. Accurate characterization of β-amyloid (Aβ40, Aβ42) standards using species-specific isotope dilution by means of HPLC-ICP-MS/MS
- Author
-
Gunda Koellensperger, Gerrit Hermann, Sarah Theiner, and Martin Schaier
- Subjects
Peptide ,Cysteic acid ,Isotope dilution ,Biochemistry ,Hydrolysate ,Analytical Chemistry ,chemistry.chemical_compound ,Hydrolysis ,Isotopes ,Tandem Mass Spectrometry ,ICP-MS ,Sample preparation ,Chromatography, High Pressure Liquid ,chemistry.chemical_classification ,Amyloid beta-Peptides ,Chromatography ,Methionine ,Traceability ,Peptide Fragments ,Amino acid ,chemistry ,Amyloid beta peptide ,Speciation analysis ,Species-specific isotope dilution ,Alzheimer’s disease ,Research Paper - Abstract
The amyloid β peptide, as one of the main components in senile plaque, represents a defining pathological feature for Alzheimer’s disease, and is therefore commonly used as a biomarker for this disease in clinical analysis. However, the selection of suitable standards is limited here, since only a few are commercially available, and these suffer from varying purity. Hence, the accurate characterization of these standards is of great importance. In this study, we developed a method for the traceable quantification of the peptide content using species-specific isotope dilution and ICP-MS/MS detection. It is based on the separation of the sulfur-containing amino acids methionine and cysteine after oxidation and hydrolysis of the peptide. Using a strong anion exchange column, both amino acids could be separated from each other, as well as from their oxidized forms and sulfate. The sulfur content was determined via ICP-MS/MS using oxygen as reaction gas. Species-specific isotope dilution was enabled by using a 34S-labeled yeast hydrolysate, containing methionine sulfone and cysteic acid with different isotopic composition. The peptide contents of Aβ standards (Aβ40,42), as well as myoglobin and lysozyme with different degrees of purity, were determined. For validation purposes, the standard reference material NIST 2389a, which contains the amino acids in a similar concentration, was subjected to the developed sample preparation and analysis method. In addition to accounting for errors during sample preparation, high levels of accuracy and precision could be obtained using this method, making it fit-for-purpose for the characterization of peptide standards. Graphical abstract
- Published
- 2021
43. The stability and calibration of water vapor isotope ratio measurements during long-term deployments.
- Author
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Bailey, A., Noone, D., Berkelhammer, M., Steen-Larsen, H. C., and Sato, P.
- Subjects
WATER vapor ,SPECTROMETERS ,HYDROLOGIC cycle ,ISOTOPES ,SIGNAL-to-noise ratio - Abstract
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]
- Published
- 2015
- Full Text
- View/download PDF
44. An automated setup to measure paleoatmospheric δ13C-CH4, δ15N-N2O and δ18O-N2O in one ice core sample.
- Author
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Sperlich, P., Buizert, C., Jenk, T. M., Sapart, C. J., Prokopiou, M., Röckmann, T., and Blunier, T.
- Subjects
ICE cores ,ISOTOPES ,HELIUM ,GAS flow ,GAS chromatography ,MASS spectrometers - Abstract
Air bubbles in ice core samples represent the only opportunity to study the isotopic variability of paleoatmospheric CH
4 and N2 O. The highest possible precision in isotope measurements is required to maximize the resolving power for CH4 and N2 O sink and source reconstructions. We present a new setup to measure δ13 C-CH4 , δ15 N-N2 O and δ18 O-N2 O 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 N2 O. The isotope ratios are referenced to the VPDB scale (δ13 C-CH4 ), the N2 -air scale (δ15 N-N2 O) and the VSMOW scale (δ18 O-N2 O). 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 N2 O sample. CH4 and N2 O are then separated from N2 , O2 , Ar and CO2 before they get pre-concentrated and separated by gas chromatography. While the separated N2 O sample is immediately analysed in the mass spectrometer, a combustion unit is required for δ13 C-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 δ13 C-CH4 analysis which is used to measure δ15 N-N2 O and δ18 O-N2 O first and then δ13 C-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 N2 O on the same IRMS. After the extraction of the air from the ice core sample, the analysis of CH4 and N2 O 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 δ13 C-CH4 that are of excellent reproducibility and accuracy, and in good agreement with previously published data. [ABSTRACT FROM AUTHOR]- Published
- 2013
- Full Text
- View/download PDF
45. Temperature-Dependent Intracellular Distribution of Thyroxine in Amphibian Liver
- Author
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Griswold, Michael D., Fischer, Mark S., and Cohen, Philip P.
- Published
- 1972
46. The Metabolism of L-Threonine and Glycine by Escherichia coli
- Author
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Miller, Dorothy A. and Simmonds, Sofia
- Published
- 1957
47. Carbon sources in the Beaufort Sea revealed by molecular lipid biomarkers and compound specific isotope analysis.
- Author
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Tolosa, I., Fiorini, S., Gasser, B., Martín, J., and Miquel, J. C.
- Subjects
MOLECULAR biology ,CARBON compounds ,LIPIDS ,BIOMARKERS ,ISOTOPES ,HYDROCARBONS ,PARTICULATE matter - Abstract
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, C
3 terrestrial 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, C3 terrestrial, 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 C3 terrestrial 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 C3 terrestrial 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 C3 terrestrial 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]- Published
- 2012
- Full Text
- View/download PDF
48. Strategies for uncovering stable isotope tracing patterns between cell populations.
- Author
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MacPherson S, Duncan KD, Goodlett DR, and Lum JJ
- Subjects
- Animals, Humans, Mice, Isotopes, Isotope Labeling
- Abstract
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.)
- Published
- 2023
- Full Text
- View/download PDF
49. Development of a new JMA flask sampling and trace gas measuring system for observation on a cargo aircraft C-130H.
- Author
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Tsuboi, K., Matsueda, H., Sawa, Y., Niwa, Y., Nakamura, M., Kuboike, D., Saito, K., Ohmori, H., Iwatsubo, S., Nishi, H., Hanamiya, Y., Tsuji, K., and Baba, Y.
- Subjects
AIR sampling ,TRANSPORT planes ,GOVERNMENT agencies ,QUALITY assurance ,HARMONIC analyzers ,ISOTOPES - Abstract
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.
- Published
- 2012
- Full Text
- View/download PDF
50. A combustion setup to precisely reference δ13C and δ2H isotope ratios of pure CH4 to produce isotope reference gases of δ13C-CH4 in synthetic air.
- Author
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Sperlich, P., Guillevic, M., Buizert, C., Jenk, T. M., Sapart, C. J., Schaefer, H., and Blunier, T.
- Subjects
ATMOSPHERIC methane ,ISOTOPES ,ATMOSPHERIC research ,CLIMATOLOGY ,ATMOSPHERIC chemistry - Abstract
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.
- Published
- 2012
- Full Text
- View/download PDF
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