ORCID Profile
0000-0002-3275-710X
Current Organisation
University of Wollongong
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Publisher: Informa UK Limited
Date: 17-02-2022
Publisher: American Geophysical Union (AGU)
Date: 05-2021
DOI: 10.1029/2020GC009588
Abstract: Increased use and improved methodology of carbonate clumped isotope thermometry has greatly enhanced our ability to interrogate a suite of Earth‐system processes. However, interlaboratory discrepancies in quantifying carbonate clumped isotope (Δ 47 ) measurements persist, and their specific sources remain unclear. To address interlaboratory differences, we first provide consensus values from the clumped isotope community for four carbonate standards relative to heated and equilibrated gases with 1,819 in idual analyses from 10 laboratories. Then we analyzed the four carbonate standards along with three additional standards, spanning a broad range of δ 47 and Δ 47 values, for a total of 5,329 analyses on 25 in idual mass spectrometers from 22 different laboratories. Treating three of the materials as known standards and the other four as unknowns, we find that the use of carbonate reference materials is a robust method for standardization that yields interlaboratory discrepancies entirely consistent with intralaboratory analytical uncertainties. Carbonate reference materials, along with measurement and data processing practices described herein, provide the carbonate clumped isotope community with a robust approach to achieve interlaboratory agreement as we continue to use and improve this powerful geochemical tool. We propose that carbonate clumped isotope data normalized to the carbonate reference materials described in this publication should be reported as Δ 47 (I‐CDES) values for Intercarb‐Carbon Dioxide Equilibrium Scale.
Publisher: Elsevier BV
Date: 2015
Publisher: Elsevier BV
Date: 11-2019
Publisher: Copernicus GmbH
Date: 22-09-2022
DOI: 10.5194/ESSD-14-4271-2022
Abstract: Abstract. The values and distribution patterns of the strontium (Sr) isotope ratio 87Sr/86Sr in Earth surface materials are of use in the geological, environmental, and social sciences. Ultimately, the 87Sr/86Sr ratios of soils and everything that lives in and on them are inherited from the rocks that are the parent materials of the soil's components. In Australia, there are few large-scale surveys of 87Sr/86Sr available, and here we report on a new, low-density dataset using 112 catchment outlet (floodplain) sediment s les covering 529 000 km2 of inland southeastern Australia (South Australia, New South Wales, Victoria). The coarse ( mm) fraction of bottom sediment s les (depth ∼ 0.6–0.8 m) from the National Geochemical Survey of Australia were milled and fully digested before Sr separation by chromatography and 87Sr/86Sr determination by multicollector-inductively coupled plasma mass spectrometry. The results show a wide range of 87Sr/86Sr values from a minimum of 0.7089 to a maximum of 0.7511 (range 0.0422). The median 87Sr/86Sr (± median absolute deviation) is 0.7199 (± 0.0071), and the mean (± standard deviation) is 0.7220 (± 0.0106). The spatial patterns of the Sr isoscape observed are described and attributed to various geological sources and processes. Of note are the elevated (radiogenic) values (≥∼ 0.7270 top quartile) contributed by (1) the Palaeozoic sedimentary country rock and (mostly felsic) igneous intrusions of the Lachlan geological region to the east of the study area (2) the Palaeoproterozoic metamorphic rocks of the central Broken Hill region both these sources contribute radiogenic material mainly by fluvial processes and (3) the Proterozoic to Palaeozoic rocks of the Kanmantoo, Adelaide, Gawler, and Painter geological regions to the west of the area these sources contribute radiogenic material mainly by aeolian processes. Regions of low 87Sr/86Sr (≤∼ 0.7130 bottom quartile) belong mainly to (1) a few central Murray Basin catchments (2) some Darling Basin catchments in the northeast and (3) a few Eromanga geological region-influenced catchments in the northwest of the study area these sources contribute unradiogenic material mainly by fluvial processes. The new spatial Sr isotope dataset for the DCD (Darling–Curnamona–Delamerian) region is publicly available (de Caritat et al., 2022 0.26186/146397).
Publisher: Research Square Platform LLC
Date: 08-07-2022
DOI: 10.21203/RS.3.RS-1802626/V1
Abstract: Chronic kidney disease (CKD) is a global health problem affecting ~10% of the global population. The largest contributor to morbidity and mortality in patients with CKD is cardiovascular disease, also the leading cause of death in those with kidney failure. One of the strongest predictors of cardiovascular risk is vascular calcification, however due to the lack of appropriate diagnostic tools it is not routinely screened. In this study, we investigate whether naturally occurring calcium (Ca) isotopes in serum or urine could be used as a non-invasive marker of vascular calcification in CKD. We recruited 28 controls, 9 participants with mild-moderate CKD, 22 undertaking dialysis and 19 who received a kidney transplant. While we found no significant association of urine Ca isotope composition between the different groups, Ca isotope compositions in serum were significantly different between groups (p .01). Receiver Operating Characteristic curve analysis shows that serum Ca isotopes are a very good diagnostic test for detecting medial calcification (AUC = 0.818, sensitivity 81.8% and specificity 77.3%, p .01) and perform better than existing biomarkers. As a minimally invasive diagnostic tool, serum Ca isotopes have the potential to be used as an early screening test for vascular calcification.
Publisher: Elsevier BV
Date: 10-2015
Publisher: Elsevier BV
Date: 03-2019
No related grants have been discovered for Florian Dux.