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Artykuły w czasopismach na temat „Ca isotope”

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Data publikacji: 6 września 2023

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1

Brown, Shaun T., Anirban Basu, Xin Ding, John N. Christensen, and Donald J. DePaolo. "Uranium isotope fractionation by abiotic reductive precipitation." Proceedings of the National Academy of Sciences 115, no. 35 (2018): 8688–93. http://dx.doi.org/10.1073/pnas.1805234115.

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Significant uranium (U) isotope fractionation has been observed during abiotic reduction of aqueous U, counter to the expectation that uranium isotopes are only fractionated by bioassociated enzymatic reduction. In our experiments, aqueous U is removed from solution by reductive precipitation onto the surfaces of synthetic iron monosulfide. The magnitude of uranium isotopic fractionation increases with decreasing aqueous U removal rate and with increasing amounts of neutrally charged aqueous Ca–U–CO3 species. Our discovery means that abiotic U isotope fractionation likely occurs in any reducin

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Han, Guilin, Anton Eisenhauer, Jie Zeng, and Man Liu. "Calcium Biogeochemical Cycle in a Typical Karst Forest: Evidence from Calcium Isotope Compositions." Forests 12, no. 6 (2021): 666. http://dx.doi.org/10.3390/f12060666.

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In order to better constrain calcium cycling in natural soil and in soil used for agriculture, we present the δ44/40Ca values measured in rainwater, groundwater, plants, soil, and bedrock samples from a representative karst forest in SW China. The δ44/40Ca values are found to differ by ≈3.0‰ in the karst forest ecosystem. The Ca isotope compositions and Ca contents of groundwater, rainwater, and bedrock suggest that the Ca of groundwater primarily originates from rainwater and bedrock. The δ44/40Ca values of plants are lower than that of soils, indicating the preferential uptake of light Ca is

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3

Antonelli, Michael A., Tushar Mittal, Anders McCarthy, Barbara Tripoli, James M. Watkins, and Donald J. DePaolo. "Ca isotopes record rapid crystal growth in volcanic and subvolcanic systems." Proceedings of the National Academy of Sciences 116, no. 41 (2019): 20315–21. http://dx.doi.org/10.1073/pnas.1908921116.

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Kinetic calcium isotope effects can be used as growth-rate proxies for volcanic and subvolcanic minerals. Here, we analyze Ca isotopic compositions in experimental and natural samples and confirm that large kinetic effects (>2‰) can occur during magmatic plagioclase crystallization. Experiments confirm theoretical predictions that disequilibrium isotope effects depend mainly on the rates for crystal growth relative to liquid phase Ca diffusivity (R/D). Plagioclase phenocrysts from the 1915 Mount Lassen rhyodacite eruption, the ∼650-y-old Deadman Creek Dome eruption, and several mafic subvol

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Merrett, Deborah C., Christina Cheung, Christopher Meiklejohn, and Michael P. Richards. "Stable isotope analysis of human bone from Ganj Dareh, Iran, ca. 10,100 calBP." PLOS ONE 16, no. 3 (2021): e0247569. http://dx.doi.org/10.1371/journal.pone.0247569.

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We report here on stable carbon, nitrogen, and sulfur isotope values from bone collagen of human (n = 20) and faunal (n = 11) remains from the Early Neolithic site of Ganj Dareh, Iran, dating to ca. 10,100 cal. BP. Our focus explores how isotope values of human bone vary by age and sex, and evaluates dietary practices at this site. It also provides a baseline for future studies of subsistence in the early Holocene Central Zagros Mountains, from the site with the first evidence for human ovicaprid management in the Near East. Human remains include individuals of all age groups for dietary recon

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5

Adloff, Markus, Andy Ridgwell, Fanny M. Monteiro, et al. "Inclusion of a suite of weathering tracers in the cGENIE Earth system model – muffin release v.0.9.23." Geoscientific Model Development 14, no. 7 (2021): 4187–223. http://dx.doi.org/10.5194/gmd-14-4187-2021.

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Abstract. The metals strontium (Sr), lithium (Li), osmium (Os) and calcium (Ca), together with their isotopes, are important tracers of weathering and volcanism – primary processes which shape the long-term cycling of carbon and other biogeochemically important elements at the Earth's surface. Traditionally, because of their long residence times in the ocean, isotopic shifts in these four elements observed in the geologic record are almost exclusively interpreted with the aid of isotope-mixing, tracer-specific box models. However, such models may lack a mechanistic description of the links bet

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6

Martin, Jeremy E., Derek Vance, and Vincent Balter. "Magnesium stable isotope ecology using mammal tooth enamel." Proceedings of the National Academy of Sciences 112, no. 2 (2014): 430–35. http://dx.doi.org/10.1073/pnas.1417792112.

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Geochemical inferences on ancient diet using bone and enamel apatite rely mainly on carbon isotope ratios (δ13C) and to a lesser extent on strontium/calcium (Sr/Ca) and barium/calcium (Ba/Ca) elemental ratios. Recent developments in nontraditional stable isotopes provide an unprecedented opportunity to use additional paleodietary proxies to disentangle complex diets such as omnivory. Of particular relevance for paleodietary reconstruction are metals present in large quantity in bone and enamel apatite, providing that biologically mediated fractionation processes are constrained. Calcium isotop

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7

Mirosław-Grabowska, Joanna. "Isotope record of environmental changes at the Skaliska Basin during the Late Glacial and Holocene." Acta Palaeobotanica 53, no. 1 (2013): 105–14. http://dx.doi.org/10.2478/acpa-2013-0008.

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ABSTRACT The results of isotopic investigations of the Skaliska Basin sediments are presented. Stable isotope analyses were done for authigenic carbonates from three profiles: W1 - Piotrowo-Ławniki, W2 - Sąkieły Małe, and W4 - Budzewo. The profiles contain carbonate silts at the bottom, then calcareous detritus gyttja and organic silts and peat at the top. Palynological data indicate that sediment were accumulated in the Skaliska Basin from the final phase of the Younger Dryas to the Subboreal period. The values δ18O change from ca −9.4 to −4.5‰, and δ13C values varies from −5.1 to +0.1‰. Such

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8

Li, Chaofeng, Huiqian Wu, Xuance Wang, Zhuyin Chu, Youlian Li, and Jinghui Guo. "Determination of Lead Elemental Concentration and Isotopic Ratios in Coal Ash and Coal Fly Ash Reference Materials Using Isotope Dilution Thermal Ionization Mass Spectrometry." International Journal of Environmental Research and Public Health 16, no. 23 (2019): 4772. http://dx.doi.org/10.3390/ijerph16234772.

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The rapid expansion of coal-fired power plants around the world has produced a huge volume of toxic elements associated with combustion residues such as coal fly ash (CFA) and coal ash (CA), which pose great threats to the global environment. It is therefore crucial for environmental science to monitor the migration and emission pathway of toxic elements such as CFA and CA. Lead isotopes have proved to be powerful tracers capable of dealing with this issue. Unfortunately, up to now, few high precision lead isotope data of CFA and CA certified reference materials (CRMs) determined by using the

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9

Heydarizad, Mojtaba, and Rogert Sorí. "Application of Statistical Techniques to Study Stable Isotopes (18O and 2H) Characteristics of Precipitation in Iran (Southwest Asia)." Environmental Sciences Proceedings 8, no. 1 (2021): 5. http://dx.doi.org/10.3390/ecas2021-10298.

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Various climatic and geographic parameters influence precipitation in Iran, which makes the interpretation of stable isotope signatures in precipitation very complicated. Thus, precipitation sampling stations for stable isotope analyses in Iran have been classified by cluster analysis (CA) into 10 clusters, based on their stable isotope characteristics. The classification of stations by CA also has a close correlation with the Koppen climatic zones across Iran. Finally, the stations in each cluster were plotted on the GMWL and EMMWL. This study shows that classifying precipitation sampling sta

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10

Griffin, Ian J., and Steven A. Abrams. "Methodological considerations in measuring human calcium absorption: relevance to study the effects of inulin-type fructans." British Journal of Nutrition 93, S1 (2005): S105—S110. http://dx.doi.org/10.1079/bjn20041344.

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During the last 50 years, a variety of methods have been developed to estimate Ca absorption in man. Mass balances were initially used, but these were unable to accurately measure fractional Ca absorption because they cannot distinguish unabsorbed dietary Ca from endogenous faecal Ca excretion (excretion of previously absorbed Ca back into the gut). A number of isotopic methods have been developed that can measure true fractional Ca absorption, employing radioisotopes, stable isotopes, or both. Different methods involve collection of urine, faecal or plasma samples. Of the currently available

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11

Gordon, Gwyneth W., Jorge Monge, Melanie B. Channon, et al. "Calcium Isotopic Composition and Its Association With Multiple Myeloma Disease Activity." Blood 122, no. 21 (2013): 3157. http://dx.doi.org/10.1182/blood.v122.21.3157.3157.

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Abstract Multiple myeloma (MM) is characterized by clonal proliferation of a neoplastic plasma cell and its production of a monoclonal immunoglobulin; evolving from an asymptomatic pre-malignant stage named monoclonal gammopathy of undetermined significance (MGUS). At the time of diagnosis with MM, lytic lesions are present in approximately 70-80% of patients. Lytic lesions increase the risk for skeletal related events as well as treatment costs, while lowering quality of life and overall survival. Metastatic bone surveys underestimate bone disease since plain radiographs demonstrate abnormali

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12

Gaigalas, Algirdas, and Stanislaw Halas. "Stable Isotopes (H, C, S) and the Origin of Baltic Amber." Geochronometria 33, no. -1 (2009): 33–36. http://dx.doi.org/10.2478/v10003-009-0001-9.

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Stable Isotopes (H, C, S) and the Origin of Baltic Amber New results of isotope analysis of light elements (H, C and S) of a dozen Baltic amber samples are described and discussed. Carbon isotope composition was nearly constant (ca. -23‰), whereas sulphur and hydrogen varied in their isotope compositions from +4 to -28‰ and from -171 to -213‰, respectively. The formation and subsequent evolution of this material since its origin in Paleogene time until present is outlined.

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13

Pessôa, G. S., and M. A. Z. Arruda. "Incorporation of67Zn and68Zn into carbonic anhydrase: effects on isotope enrichment and enzymatic aspects." Journal of Analytical Atomic Spectrometry 32, no. 8 (2017): 1473–80. http://dx.doi.org/10.1039/c7ja00061h.

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14

Fantle, M. S. "Evaluating the Ca isotope proxy." American Journal of Science 310, no. 3 (2010): 194–230. http://dx.doi.org/10.2475/03.2010.03.

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15

Yakovlev, O. I., and S. I. Shornikov. "Theoretical analyses of chemical and magnesium and silica isotope fractionation during vaporization of ca-al-inclusion of chondrite." Геохимия 64, no. 8 (2019): 777–93. http://dx.doi.org/10.31857/s0016-7525648777-793.

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Experimental study of changes in the composition of Ca-Al-inclusions of chondrites during evaporation indicates a close relationship of chemical and isotopic fractionation of this substance. The theoretical description of the coupling is carried out using the equations of the evaporation rate of the melt component (the Hertz-Knudsen equation) and isotope Rayleigh fractionation. The form of Rayleigh equation taken in foreign literature, derived from the Hertz-Knudsen equation, faces difficulties in interpreting experimental data. The discrepancy between the experimental and model data is explai

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16

Tacail, Théo, Philippe Télouk, and Vincent Balter. "Precise analysis of calcium stable isotope variations in biological apatites using laser ablation MC-ICPMS." Journal of Analytical Atomic Spectrometry 31, no. 1 (2016): 152–62. http://dx.doi.org/10.1039/c5ja00239g.

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17

Taylor, Holly L., Isaac J. Kell Duivestein, Juraj Farkas, Martin Dietzel, and Anthony Dosseto. "Technical note: Lithium isotopes in dolostone as a palaeo-environmental proxy – an experimental approach." Climate of the Past 15, no. 2 (2019): 635–46. http://dx.doi.org/10.5194/cp-15-635-2019.

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Abstract. Lithium (Li) isotopes in marine carbonates have considerable potential as a proxy to constrain past changes in silicate weathering fluxes and improve our understanding of Earth's climate. To date the majority of Li isotope studies on marine carbonates have focussed on calcium carbonates. The determination of the Li isotope fractionation between dolomite and a dolomitizing fluid would allow us to extend investigations to deep times (i.e. Precambrian) when dolostones were the most abundant marine carbonate archives. Dolostones often contain a significant proportion of detrital silicate

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18

Letulle, Thomas, Danièle Gaspard, Mathieu Daëron, et al. "Multi-proxy assessment of brachiopod shell calcite as a potential archive of seawater temperature and oxygen isotope composition." Biogeosciences 20, no. 7 (2023): 1381–403. http://dx.doi.org/10.5194/bg-20-1381-2023.

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Abstract. Most of our knowledge of past seawater temperature history is based on δ18O values of calcium carbonate fossil shells. However, the determination of past temperatures using this proxy requires the knowledge of past seawater δ18O values, which is generally poorly constrained. Other paleothermometers using carbonate archives, such as Mg/Ca ratios and clumped isotopes (Δ47), have been developed to allow for paleotemperatures to be estimated independently and to allow past ocean δ18O values to be calculated using various groups of calcifying organisms. Articulated brachiopod shells are s

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19

Vezinet, Adrien, Emilie Thomassot, Yan Luo, Chiranjeeb Sarkar, and D. Graham Pearson. "Diachronous Redistribution of Hf and Nd Isotopes at the Crystal Scale—Consequences for the Isotopic Evolution of a Poly-Metamorphic Crustal Terrane." Geosciences 12, no. 1 (2022): 36. http://dx.doi.org/10.3390/geosciences12010036.

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In metamorphic rocks, mineral species react over a range of pressure–temperature conditions that do not necessarily overlap. Mineral equilibration can occur at varied points along the metamorphic pressure–temperature (PT) path, and thus at different times. The sole or dominant use of zircon isotopic compositions to constrain the evolution of metamorphic rocks might then inadvertently skew geological interpretations towards one aspect or one moment of a rock’s history. Here, we present in-situ U–Pb/Sm–Nd isotope analyses of the apatite crystals extracted from two meta-igneous rocks exposed in t

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20

Eerkens, Jelmer W., Eric J. Bartelink, Laura Brink, et al. "Trophy Heads or Ancestor Veneration? A Stable Isotope Perspective on Disassociated and Modified Crania in Precontact Central California." American Antiquity 81, no. 1 (2016): 114–31. http://dx.doi.org/10.7183/0002-7316.81.1.114.

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AbstractFew items in the archaeological record capture the imagination more than human heads separated from their bodies. Such items are sometimes assumed to indicate warfare practices, where “trophy heads” display power and fighting prowess. Other times, they are interpreted as representing ancestor veneration. Isolated crania are not uncommon in the Early period (ca. 4500–2500 B.P.) in Central California. Some anthropologists interpret them as trophy heads, but isotopie analyses at CA-CCO-548 suggest an alternative interpretation. Strontium isotope analyses on one modified cranium produced v

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21

Fiket, Željka, Martina Furdek Turk, Maja Ivanić, and Goran Kniewald. "Non-traditional stable isotope signatures in geological matrices as a tool for interpreting environmental changes – a review." Geologia Croatica 74, no. 2 (2021): 177–87. http://dx.doi.org/10.4154/gc.2021.12.

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The development of new analytical techniques enabled the precise determination of the expanded set of stable isotopes and provided new insight into existing geological issues. This review outlines recent studies of non-traditional isotope signatures in geological matrices, summarizing in one place, new data for the stable isotopes of Ca, Mg, Sr, Li, Ni, Cr, and Cu and their application in the interpretation of environmental processes. Although some, such as δ44Ca and δ26Mg, have previously been used to track changes in seawater chemistry throughout geological history, recent studies report the

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Hassler, A., J. E. Martin, R. Amiot, et al. "Calcium isotopes offer clues on resource partitioning among Cretaceous predatory dinosaurs." Proceedings of the Royal Society B: Biological Sciences 285, no. 1876 (2018): 20180197. http://dx.doi.org/10.1098/rspb.2018.0197.

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Large predators are overabundant in mid-Cretaceous continental dinosaur assemblages of North Africa. Such unbalanced ecosystem structure involves, among predatory dinosaurs, typical abelisaurid or carcharodontosaurid theropods co-occurring with long-snouted spinosaurids of debated ecology. Here, we report calcium (Ca) isotope values from tooth enamel (expressed as δ 44/42 Ca) to investigate resource partitioning in mid-Cretaceous assemblages from Niger (Gadoufaoua) and Morocco (Kem Kem Beds). In both assemblages, spinosaurids display a distinct isotopic signature, the most negative in our data

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Herbert, Timothy D., Rocio Caballero-Gill, and Joseph B. Novak. "A revised mid-Pliocene composite section centered on the M2 glacial event for ODP Site 846." Climate of the Past 17, no. 3 (2021): 1385–94. http://dx.doi.org/10.5194/cp-17-1385-2021.

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Abstract. The composite section from ODP Site 846 has provided key data sets for Pliocene stable isotope and paleoclimatic time series. We document here apparent outliers in previously published data sets for stable isotopes and alkenone-derived sea surface temperature (SST) estimates in the Pliocene interval containing the M2 glaciation (ca. 3.290–3.3 Ma) by tying high-resolution core measurements to a continuous downhole conductivity log. We generate a revised sequence of new stable isotopic and alkenone measurements across the M2 event that correlate well to the revised splices of color ref

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24

Rossete, Alexssandra Luiza Rodrigues Molina, Josiane Meire Toloti Carneiro, José Albertino Bendassolli, Claudineia Raquel Oliveira Tavares, and Carlos Roberto Sant'Ana Filho. "Production of single superphosphate labeled with 34S." Scientia Agricola 65, no. 1 (2008): 91–94. http://dx.doi.org/10.1590/s0103-90162008000100013.

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Single superphosphate is currently one of the mostly used fertilizers as an alternative source for phosphorus and sulphur. Sulphur presents four stable isotopes (32S, 33S, 34S, and 36S) with natural abundances of 95.00; 0.76; 4.22; and 0.014% in atoms, respectively. Single superphosphate labeled with the 34S isotope was obtained from a chemical reaction in stoichiometric amounts between Ca(H2PO4)2 and Ca34SO4.2H2O. Calcium sulphate (Ca34SO4.2H2O) was enriched with 5.85 ± 0.01 atoms % of 34S. The Ca(H2PO4)2 reagent was obtained from a reaction between CaCl2.2H2O and H3PO4. The reaction between

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25

Blättler, C. L., S. M. Stanley, G. M. Henderson, and H. C. Jenkyns. "Identifying vital effects in <i>Halimeda</i> algae with Ca isotopes." Biogeosciences Discussions 11, no. 3 (2014): 3559–80. http://dx.doi.org/10.5194/bgd-11-3559-2014.

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Abstract. Geochemical records of biogenic carbonates provide some of the most valuable records of the geological past, but are often difficult to interpret without a mechanistic understanding of growth processes. In this experimental study, Halimeda algae are used as a test organism to untangle some of the specific factors that influence their skeletal composition, in particular their Ca-isotope composition. Algae were stimulated to precipitate both calcite and aragonite by growth in artificial Cretaceous seawater. The Ca-isotope fractionation of the algal calcite is much smaller than that for

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26

Fantle, Matthew S., and Edward T. Tipper. "Calcium isotopes in the global biogeochemical Ca cycle: Implications for development of a Ca isotope proxy." Earth-Science Reviews 129 (February 2014): 148–77. http://dx.doi.org/10.1016/j.earscirev.2013.10.004.

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Fujii, Y., J. Hoshi, H. Iwamoto, M. Okamoto, and H. Kakihana. "Calcium Isotope Effects in Ion Exchange Electromigration and Calcium Isotope Analysis by Thermo-Ionization Mass Spectrometry." Zeitschrift für Naturforschung A 40, no. 8 (1985): 843–48. http://dx.doi.org/10.1515/zna-1985-0807.

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Calcium ions were made to electromigrate along a cation exchange membrane. The abundance ratios of the calcium isotopes (Ca-40, 42, 43, 44, 48) in the migrated bands were measured by thermo-ionization mass spectrometry. The lighter isotopes were enriched in the front part of the migrated band. The increments in the isotope abundance ratios were found to be proportional to the mass differences of the isotopes. The observed e-values per unit mass difference (ε/ΔM) were 1.26 x 10-4 (at 20 °C), 1.85 x 10-4 (at 25 °C) and 2.4 x 10-4 (at 40 °C). The mass spectrometry was improved by using a low temp

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Blättler, C. L., S. M. Stanley, G. M. Henderson, and H. C. Jenkyns. "Identifying vital effects in <i>Halimeda</i> algae with Ca isotopes." Biogeosciences 11, no. 24 (2014): 7207–17. http://dx.doi.org/10.5194/bg-11-7207-2014.

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Abstract. Geochemical records of biogenic carbonates provide some of the most valuable records of the geological past, but are often difficult to interpret without a mechanistic understanding of growth processes. In this experimental study, Halimeda algae are used as a test organism to untangle some of the specific factors that influence their skeletal composition, in particular their Ca-isotope composition. Algae were stimulated to precipitate both calcite and aragonite by growth in artificial Cretaceous seawater, resulting in experimental samples with somewhat malformed skeletons. The Ca-iso

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29

Feng, Lianjun, Hongwei Li, and Tiejun Li. "Potential Reference Materials for Hematite Oxygen Isotope Analysis." Minerals 10, no. 11 (2020): 987. http://dx.doi.org/10.3390/min10110987.

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Hematite is a potential mineral for reconstructing the oxygen isotope composition and paleotemperature of paleowater. A highly accurate analysis of oxygen isotopes is essential. However, relative to other oxygenated minerals, we lack hematite reference materials that allow for internationally comparable analyses between different laboratories. To address this issue, we attempted to perform bulk rock oxygen isotope analysis on five hematite reference materials (GBW07223a, GBW07825, YSBC28740-95, YSBC28756-2008, Harvard 92649). Meanwhile, the oxygen isotope ratios of iron oxides (GBW07223a, GBW0

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Wang, Peng, Ting Liang, HongJun Jiang, XinKui Xiang, and Bo Zhong. "Trace Elements and Pb-O Isotopes of Scheelite: Metallogenic Implications for the Shimensi W-Polymetallic Deposit in South China." Minerals 12, no. 11 (2022): 1461. http://dx.doi.org/10.3390/min12111461.

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The world-class Shimensi tungsten (W)-polymetallic deposit is located in Jiangnan Orogen, with an estimated reserve of 742.5 kt WO3 @ 0.195% W, 403.6 kt Cu and 28 kt Mo. In this paper, the trace elements and Pb-O isotopes of scheelite (the main ore mineral) are presented to study the ore-forming material source and ore-forming fluid evolution. The results show that the REE distribution in scheelite is mainly controlled by the substitution mechanism of 3Ca2+ = 2REE3+ + □Ca (where □Ca is the Ca-site vacancy). Oxygen isotope data indicate that the scheelite mineralization occurred under high-temp

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Aladejana, Jamiu A., Robert M. Kalin, Ibrahim Hassan, Philippe Sentenac та Moshood N. Tijani. "Origin and Residence Time of Groundwater in the Shallow Coastal Aquifer of Eastern Dahomey Basin, Southwestern Nigeria, Using δ18O and δD Isotopes". Applied Sciences 10, № 22 (2020): 7980. http://dx.doi.org/10.3390/app10227980.

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This study employed stable isotopes of δ18O and δ2H in conjunction with other hydrological parameters to understand the origin, inferred residence time, and seasonal effect of groundwater in the shallow aquifers of the eastern Dahomey Basin. A total of 230 groundwater samples (97 in the wet season and 133 in the dry season) were collected from the borehole and shallow aquifer between May 2017 and April 2018. Groundwater analysis included major ions and δ18O and δ2H, isotopes data in precipitation from three selected Global Network of Isotope in Precipitation (GNIP) stations across West Africa,

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LIU, J. Y., HUAN FENG HAO, YONG ZHONG XING, WEI ZUO, and XI GUO LEE. "INFLUENCES OF THE ISOSPIN-DEPENDENCE OF IN-MEDIUM NUCLEON–NUCLEON CROSS-SECTION AND MOMENTUM DEPENDENT INTERACTION ON ISOSCALING PARAMETER." International Journal of Modern Physics E 17, no. 04 (2008): 645–53. http://dx.doi.org/10.1142/s0218301308010052.

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Influences of the isospin-dependent in-medium nucleon–nucleon cross-section [Formula: see text] and momentum-dependent interaction (MDI) on the isoscaling parameter α are investigated for two central collisions 40 Ca + 40 Ca and 60 Ca + 60 Ca . These collisions are with isospin dependent quantum molecular dynamics in the beam energy region from 40 to 60 MeV/nucleon. The isotope yield ratio R21(N, Z) for the above two central collisions depends exponentially on the neutron number N and proton number Z of isotopes, with an isoscaling. In particular, the isospin-dependent [Formula: see text] and

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von Quadt, A., D. Gallhofer, M. Guillong, I. Peytcheva, M. Waelle, and S. Sakata. "U–Pb dating of CA/non-CA treated zircons obtained by LA-ICP-MS and CA-TIMS techniques: impact for their geological interpretation." J. Anal. At. Spectrom. 29, no. 9 (2014): 1618–29. http://dx.doi.org/10.1039/c4ja00102h.

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Chemical Abrasion Isotope-Dilution Thermal Ionization Mass Spectrometry (CA-ID-TIMS) is known as a high precision technique for resolving lead loss and improving the interpretation of U–Pb zircon age data.

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Caemmerer, Susanne von, Martha Ludwig, Anthony Millgate, et al. "Carbon Isotope Discrimination during C4 Photosynthesis: Insights from Transgenic Plants." Functional Plant Biology 24, no. 4 (1997): 487. http://dx.doi.org/10.1071/pp97031.

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We have measured the discrimination against 13C during CO2 assimilation in Flaveria bidentis wild type plants and in transgenic Flaveria bidentis plants transformed (1) with an antisense RNA construct targeted to the nuclear encoded gene for the small subunit of Rubisco—these plants had reduced amounts of Rubisco, decreased CO2 assimilation rates and increased carbon isotope discrimination, which was also evident in the carbon isotope discrimination of leaf dry matter; and (2) transformed with the mature coding region of carbonic anhydrase, CA, from tobacco (Nicotiana tabacum) in the sense dir

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Vigier, N., C. Rollion-Bard, and S. Spezzaferri. "In situ Ca isotope measurements in foraminifera." Geochimica et Cosmochimica Acta 70, no. 18 (2006): A672. http://dx.doi.org/10.1016/j.gca.2006.06.1257.

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Sharma, Manish, Daniel Sethio, Vincenza D’Anna, et al. "Isotope Exchange Reactions in Ca(BH4)2." Journal of Physical Chemistry C 119, no. 1 (2014): 29–32. http://dx.doi.org/10.1021/jp5082609.

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Holmden, Chris, and Nicolas Bélanger. "Ca isotope cycling in a forested ecosystem." Geochimica et Cosmochimica Acta 74, no. 3 (2010): 995–1015. http://dx.doi.org/10.1016/j.gca.2009.10.020.

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Mennekes, David, Michael Rinderer, Stefan Seeger, and Natalie Orlowski. "Ecohydrological travel times derived from in situ stable water isotope measurements in trees during a semi-controlled pot experiment." Hydrology and Earth System Sciences 25, no. 8 (2021): 4513–30. http://dx.doi.org/10.5194/hess-25-4513-2021.

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Abstract. Tree water uptake processes and ecohydrological travel times have gained more attention in recent ecohydrological studies. In situ measurement techniques for stable water isotopes offer great potential to investigate these processes but have not been applied much to tree xylem and soils so far. Here, we used in situ probes for stable water isotope measurements to monitor the isotopic signatures of soil and tree xylem water before and after two deuterium-labeled irrigation experiments. To show the potential of the method, we tested our measurement approach with 20-year-old trees of th

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Ito, Emi, Patrick De Deckker, and Stephen M. Eggins. "Ostracodes and Their Shell Chemistry: Implications for Paleohydrologic and Paleoclimatologic Applications." Paleontological Society Papers 9 (November 2003): 119–52. http://dx.doi.org/10.1017/s1089332600002187.

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The shell chemistry of ostracodes is a useful indicator of past environmental conditions especially when the chemistry data are considered along with other proxy data. The complexities involved with the chemical and isotopic changes accompanying hydrologic change, solute evolution, and the autoecology of ostracodes all point to the need to exercise caution when interpreting shell chemistry. Nevertheless, the stable-isotope values and cation ratios (e.g., Mg/Ca, Sr/Ca) as well as the species assemblage of ostracodes can provide powerful tools for the reconstruction of paleoclimate and paleohydr

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Dwyer, Gary S., and Mark A. Chandler. "Mid-Pliocene sea level and continental ice volume based on coupled benthic Mg/Ca palaeotemperatures and oxygen isotopes." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 367, no. 1886 (2008): 157–68. http://dx.doi.org/10.1098/rsta.2008.0222.

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Ostracode magnesium/calcium (Mg/Ca)-based bottom-water temperatures were combined with benthic foraminiferal oxygen isotopes in order to quantify the oxygen isotopic composition of seawater, and estimate continental ice volume and sea-level variability during the Mid-Pliocene warm period, ca 3.3–3.0 Ma. Results indicate that, following a low stand of approximately 65 m below present at marine isotope stage (MIS) M2 ( ca 3.3 Ma), sea level generally fluctuated by 20–30 m above and below a mean value similar to present-day sea level. In addition to the low-stand event at MIS M2, significant low

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Lu, Zhongying, Chengying Hai, Simin Yan, et al. "Chemistry Combining Elemental Profile, Stable Isotopic Ratios, and Chemometrics for Fine Classification of a Chinese Herb Licorice (Glycyrrhiza uralensis Fisch.) from 37 Producing Area." Journal of Analytical Methods in Chemistry 2022 (August 18, 2022): 1–9. http://dx.doi.org/10.1155/2022/8906305.

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A method based on elemental fingerprint, stable isotopic analysis and combined with chemometrics was proposed to trace the geographical origins of Licorice (Glycyrrhiza uralensis Fisch) from 37 producing areas. For elemental fingerprint, the levels of 15 elements, including Ca, Cu, Mg, Pb, Zn, Sr, Mn, Se, Cd, Fe, Na, Al, Cr, Co, and K, were analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES). Three stable isotopes, including δ13C, δ15N, and δ18O, were measured using an isotope-ratio mass spectrometer (IRMS). For fine classification, three multiclass strategies, includ

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Schöne, Bernd R., Aliona E. Meret, Sven M. Baier, et al. "Freshwater pearl mussels from northern Sweden serve as long-term, high-resolution stream water isotope recorders." Hydrology and Earth System Sciences 24, no. 2 (2020): 673–96. http://dx.doi.org/10.5194/hess-24-673-2020.

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Abstract. The stable isotope composition of lacustrine sediments is routinely used to infer Late Holocene changes in precipitation over Scandinavia and, ultimately, atmospheric circulation dynamics in the North Atlantic realm. However, such archives only provide a low temporal resolution (ca. 15 years), precluding the ability to identify changes on inter-annual and quasi-decadal timescales. Here, we present a new, high-resolution reconstruction using shells of freshwater pearl mussels, Margaritifera margaritifera, from three streams in northern Sweden. We present seasonally to annually resolve

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Yoshimura, T., A. Suzuki, and N. Iwasaki. "Mechanism of O and C isotope fractionation in magnesian calcite skeletons of <i>Octocorallia</i> corals and an implication on their calcification response to ocean acidification." Biogeosciences Discussions 12, no. 1 (2015): 389–412. http://dx.doi.org/10.5194/bgd-12-389-2015.

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Abstract. Coral calcification is strongly dependent on both the pH and the dissolved inorganic carbon (DIC) of the calcifying fluid. Skeletal oxygen and carbon isotope fractionation of high-Mg calcite skeletons of \\textit{Octocorallia} corals directly record the biological manipulation on sources of DIC in response to environmental changes. The coral skeletons were enriched in light isotopes (16O and 12C) relative to the expected values based on habitat environmental parameters and Mg/Ca of the skeletons. The differences between the expected and observed values ranged from −4.66 to −1.53 for

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Lynott, Mark J., Thomas W. Boutton, James E. Price, and Dwight E. Nelson. "Stable Carbon Isotopic Evidence for Maize Agriculture in Southeast Missouri and Northeast Arkansas." American Antiquity 51, no. 1 (1986): 51–65. http://dx.doi.org/10.2307/280393.

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Analysis of bone collagen extracted from human skeletal remains from archaeological sites dating from the Archaic period through Euro-American settlement provides evidence for the introduction of maize into regional subsistence patterns. Stable carbon isotope ratios of samples from both the eastern Ozarks and the Mississippi River alluvial valley indicate that human populations living prior to ca. A.D. 1000 consumed little or no C4 plant material. In populations dating after ca. A.D. 1000, stable carbon isotope ratios indicate that maize represented a significant part of the human diet through

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Tanaka, Yu-ki, Nobuyuki Yajima, Yusuke Higuchi, Hideyuki Yamato, and Takafumi Hirata. "Calcium isotope signature: new proxy for net change in bone volume for chronic kidney disease and diabetic rats." Metallomics 9, no. 12 (2017): 1745–55. http://dx.doi.org/10.1039/c7mt00255f.

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Herein, we measure the Ca isotope ratios (<sup>44</sup>Ca/<sup>42</sup>Ca and <sup>43</sup>Ca/<sup>42</sup>Ca) in serum and bone samples collected from rats with chronic kidney disease (CKD) or diabetes mellitus (DM).

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Uno, Kevin T., Pratigya J. Polissar, Emma Kahle, et al. "A Pleistocene palaeovegetation record from plant wax biomarkers from the Nachukui Formation, West Turkana, Kenya." Philosophical Transactions of the Royal Society B: Biological Sciences 371, no. 1698 (2016): 20150235. http://dx.doi.org/10.1098/rstb.2015.0235.

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Reconstructing vegetation at hominin fossil sites provides us critical information about hominin palaeoenvironments and the potential role of climate in their evolution. Here we reconstruct vegetation from carbon isotopes of plant wax biomarkers in sediments of the Nachukui Formation in the Turkana Basin. Plant wax biomarkers were extracted from samples from a wide range of lithologies that include fluvial–lacustrine sediments and palaeosols, and therefore provide a record of vegetation from diverse depositional environments. Carbon isotope ratios from biomarkers indicate a highly dynamic vege

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Frisia, Silvia, Andrea Borsato, Augusto Mangini, Christoph Spötl, Giuliana Madonia, and Ugo Sauro. "Holocene Climate Variability in Sicily from a Discontinuous Stalagmite Record and the Mesolithic to Neolithic Transition." Quaternary Research 66, no. 3 (2006): 388–400. http://dx.doi.org/10.1016/j.yqres.2006.05.003.

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AbstractFabric and stable isotopic composition of a Holocene stalagmite (CR1) from a cave in northern Sicily record changes in paleorainfall in the early Holocene. High δ13C stable isotope values in the calcite deposited from ca. 8500 to ca. 7500 yr ago are interpreted as reflecting periods of high rainfall. The wet phase was interrupted by two periods of multi-century duration characterized by relatively cool and dry winters centered at ca. 8200 and ca. 7500 yr ago, highlighted by low δ13C and δ18O values. A high variability of δ13C values is recorded from ca. 7500 to ca. 6500 yr ago and indi

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Grubb, B. R., and P. J. Bentley. "Calcium exchange in isolated cutaneous epithelium of toad Bufo marinus." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 249, no. 2 (1985): R172—R178. http://dx.doi.org/10.1152/ajpregu.1985.249.2.r172.

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The Ca content of isolated cutaneous epithelium of toads (Bufo marinus) was 5 mmol/kg wet wt (compared with approximately 300 mmol/kg wet wt for intact skin), of which approximately 1.7 mM is not readily exchangeable with external 45Ca. After incubation in a solution containing 45Ca, loss of the accumulated isotope in an isotope-free medium is almost complete in 2 h. This efflux or washout is reduced by the presence of external Ca- and Na-free media and by La. Loss of Ca from the epithelium may thus reflect the presence of several mechanisms including a Ca-Ca exchange and a Ca-Na exchange. The

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Mondal, Surajit, and Ramananda Chakrabarti. "A novel sample loading method and protocol for monitoring sample fractionation for high precision Ca stable isotope ratio measurements using double-spike TIMS." Journal of Analytical Atomic Spectrometry 33, no. 1 (2018): 141–50. http://dx.doi.org/10.1039/c7ja00322f.

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The external reproducibility (2σ<sub>SD</sub>) of Ca stable isotope ratio measurements (δ<sup>44/40</sup>Ca) using double-spike (<sup>43</sup>Ca–<sup>48</sup>Ca) thermal ionization mass spectrometry (TIMS) is better than 0.08 ‰ using our proposed loading technique.

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Khan, W. R., M. Nazre, S. Z. Zulkifli, et al. "Reflection of stable isotopes and selected elements with the inundation gradient at the Matang Mangrove Forest Reserve (MMFR), Malaysia." International Forestry Review 19, no. 3 (2017): 1–10. http://dx.doi.org/10.1505/146554817828562314.

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Multi-elemental and isotopic fingerprints could help to track changes in mangrove forest productivity and development. This study aims to identify elemental concentrations and stable isotope ratios in inter- and intra-mangrove species along the inundation gradient of the Matang mangrove forest. Matured sun leaves of different mangrove species, namely, Avicennia alba, Rhizophora apiculata, Bruguiera parviflora, and Sonneratia ovata, were collected from the Matang Mangrove Forest Reserve (MMFR). After samples preparation, determination of elemental concentrations and stable isotope ratios were c

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