Search results for "ISOTOPE"
showing 10 items of 2232 documents
Rapid assay of resveratrol in red wine by paper spray tandem mass spectrometry and isotope dilution.
2017
A rapid analytical approach for the assay of resveratrol in red wines, based on Paper Spray Mass Spectrometry (PS-MS) and Multiple Reaction Monitoring (MRM) is described. The assay involves the use of the stable isotope dilution method. The analytical parameters calculated analyzing fortified samples confirm the reliability of the proposed approach, with accuracy values about 100%, and LOD and LOQ values calculated at 0.5 and 0.8 μg/mL, respectively. Furthermore, both the recovery, which was quantitative for the analyte, and the reproducibility (RSD%), checked on different days on the same wine, always below 7%, highlighted the consistency of the methodology.
Data for: Refining the temperature dependence of the oxygen and clumped isotopic compositions of structurally bound carbonate in apatite
2020
Compilation of all measured and calculated data from equilibrated gases and empirical transfer functions (I.), standard (II.) and sample (III.) measurements including δ47 and raw Δ47 values. Comparison of [Brand] processed Δ47 values of ETH-1, ETH-2, and ETH-3 with Δ47 values from prior studies (IV.).The sample materials (III.) are: Synthetic hydroxyapatites, tooth enamel(oid) and dentine from African elephant (Loxodonta africana) and Greenland shark (Somniosus microcephalus), sand tiger shark tooth dentine (Carcharias taurus), and megatooth shark tooth enameloid (Carcharodon megalodon). THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE F…
Use of radiation sources with mercury isotopes for real-time highly sensitive and selective benzene determination in air and natural gas by different…
2015
A new analytical portable system is proposed for the direct determination of benzene vapor in the ambient air and natural gas, using differential absorption spectrometry with the direct Zeeman effect and innovative radiation sources: capillary mercury lamps with different isotopic compositions ((196)Hg, (198)Hg, (202)Hg, (204)Hg, and natural isotopic mixture). Resonance emission of mercury at a wavelength of 254 nm is used as probing radiation. The differential cross section of benzene absorption in dependence on wavelength is determined by scanning of magnetic field. It is found that the sensitivity of benzene detection is enhanced three times using lamp with the mercury isotope (204)Hg in…
Beyond the grave: variability in Neolithic diets in Southern Germany?
2006
Abstract Carbon and nitrogen stable isotope analyses were undertaken on human and faunal remains from two Neolithic sites in Southern Germany; the LBK settlement at Herxheim and the middle Neolithic cemetery at Trebur. Stable isotope data were used to reconstruct the diets of individuals buried at these sites and to look at dietary variation between groups classified by their sex, age, grave goods and cultural affiliation. Overall there was surprisingly little variation in the diet between the groups, as described by the stable isotope analysis, despite significant differences in the composition of grave goods. Also surprising, considering the archaeological evidence for extensive grain cul…
Effect of nonprotein thiols on protein synthesis in isolated rat hepatocytes.
1996
The ability of nonprotein thiols to modulate rates of protein synthesis was investigated in isolated rat hepatocytes. Addition of cysteine stimulates protein labelling by [14C]Leucine. Glutathione depletion, induced by in vivo administration of L-buthionine sulfoximine and diethylmaleate, did not alter the effect of cysteine, although it decreased the rate of protein synthesis by 32%. The effect of cysteine on protein synthesis does not seem to be related to a perturbation of the redox state of the NAD+/NADH system or to changes in the rate of gluconeogenic pathway. The following observations indicate that cysteine may stimulate protein synthesis by increasing intracellular levels of aspart…
Data for: The stable isotope composition of organic and inorganic fossils in lake sediment records: current understanding, challenges, and future dir…
2018
Table 1 and Supplementary Table belonging to "The stable isotope composition of organic and inorganic fossils in lake sediment records: current understanding, challenges, and future directions". THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOVE
Data for: Flotsam samples can help explain the δ13C and δ15N values of invertebrate resting stages in lake sediment records
2018
This supplementary table provides the data used in the manuscript. It gives an overview of the 53 lakes that were sampled for flotsam and (where available) their water chemistry, morphological characteristics, and stable isotope values of resting stages and sedimentary organic matter
Zooplankton, lipids and stable isotopes: importance of seasonal, latitudinal, and taxonomic differences
2010
We found considerable seasonal, latitudinal, and taxonomic differences in zooplankton lipid content and concur- rent d 13 C values of zooplankton. We collected cladoceran as well as cyclopoid and calanoid copepod zooplankton from boreal and subarctic lakes throughout a year, allowing us to study zooplankton likely subjected to different isotopic fractionation processes and with highly variable lipid contents. Considerable seasonal variation was observed in the differ- ence between bulk and lipid-extracted zooplankton d 13 C values, indicating that seasonally changing lipid content intro- duced notable variation in zooplankton d 13 C values. The difference between bulk and lipid-extracted ma…
Prospects of Ion Chemical Reactions with Heavy Elements in the Gas Phase
2001
Heavy element chemistry is related to the fundamental interest that lies in exploring the upper limits of the periodic table. Chemical properties of the heaviest elements have already been studied at single atoms in aqueous solutions and in the gas phase up to an atomic number Z = 107. These techniques allow to study nuclides with half lives as short as about 1 s. Next generation chemistry experiments could be envisaged with an ion trap technique already developed for stable isotopes. At very low production rates in the order of 1 per 100 s and/or half lives as short as about 10 ms, the ion-molecule reactions can be studied in a buffer gas cell, in which the heavy elements are stopped and t…
Sulfur isotope's signal of nanopyrites enclosed in 2.7 Ga stromatolitic organic remains reveal microbial sulfate reduction.
2018
18 pages; International audience; Microbial sulfate reduction (MSR) is thought to have operated very early on Earth and is often invoked to explain the occurrence of sedimentary sulfides in the rock record. Sedimentary sulfides can also form from sulfides produced abiotically during late diagenesis or metamorphism. As both biotic and abiotic processes contribute to the bulk of sedimentary sulfides, tracing back the original microbial signature from the earliest Earth record is challenging. We present in situ sulfur isotope data from nanopyrites occurring in carbonaceous remains lining the domical shape of stromatolite knobs of the 2.7-Gyr-old Tumbiana Formation (Western Australia). The anal…