Search results for "icp"
showing 10 items of 139 documents
Diagenetic stability of non-traditional stable isotope systems (Ca, Sr, Mg, Zn) in teeth – An in-vitro alteration experiment of biogenic apatite in i…
2021
Stable isotope ratios and trace element concentrations of fossil bones and teeth are important geochemical proxies for the reconstruction of diet and past environment in archaeology and palaeontology. However, since diagenesis can significantly alter primary diet-related isotope signatures and elemental compositions, it is important to understand and quantify alteration processes. Here, we present the results of in-vitro alteration experiments of dental tissues from a modern African elephant molar reacted in aqueous solutions at 30 °C and 90 °C for 4 to 63 days. Dental cubes with ≈ 3 mm edge length, comprising both enamel and dentin, were placed into 2 mL of acidic aqueous sol…
The geological roots of South America: 4.1 Ga and 3.7 Ga zircon crystals discovered in N.E. Brazil and N.W. Argentina
2015
International audience; We present new LA-ICP-MS in situ geochronological results for seven Eoarchean zircons dated at 3.7 Ga coming from Cretaceous ash layers of NW Argentina and one Hadean single crystal sampled within the São Francisco Craton in NE Brazil. This zircon comprises a zoned magmatic core dated at 4.1 Ga surrounded by a 1.9 Ga overgrowth related to Paleoproterozoic reworking. This Hadean age is consistent with previously published Nd model ages on orthogneisses from the same domain. These two results represent among the oldest geological witnesses discovered to date in South America, which demonstrates the occurrence of a primitive crust. The contrasting age patterns recorded …
Copper supply during the Final Neolithic at the Saint-Blaise/Bains des Dames site (Neuchâtel, Switzerland)
2009
The Saint-Blaise/Bains des Dames stratified site in Neuchâtel, Switzerland, contains several occupations that span the Late through Final Neolithic, including the Horgen, Lüscherz, and Auvernier-Cordé periods. As part of a study on prehistoric metallurgy in western Switzerland, we compare the lead isotope ratios (multicollector inductively coupled plasma mass spectrometer) and elemental compositions (instrumental neutron activation analysis) of the site's numerous copper finds to a database of corresponding measurements for copper ores throughout Europe. The results show a considerable variation in copper compositions present at the site, suggesting complex economic relationships and multip…
The first archaeometric characterization of obsidian artifacts from the archaeological site of Samshvilde (South Georgia, Caucasus)
2019
This paper presents the first results about the provenance of obsidian fragments recovered in the archaeological site of Samshvilde (South Georgia, Caucasus) with the aim to obtain knowledge related to the network distribution and procurement of obsidian in Georgia. The geochemical characterization of thirty archaeological finds was obtained by the LA-ICP-MS method, an almost non-destructive technique capable of chemically characterizing the volcanic glass. A comparison of geochemical results obtained on both archaeological artefacts and geological samples collected from Chikiani outcrop in Georgia, together with literature data of southern Caucasus and eastern Turkey, allowed us to define …
High Quality Reconstruction of Dynamic Objects using 2D-3D Camera Fusion
2017
International audience; In this paper, we propose a complete pipeline for high quality reconstruction of dynamic objects using 2D-3D camera setup attached to a moving vehicle. Starting from the segmented motion trajectories of individual objects, we compute their precise motion parameters, register multiple sparse point clouds to increase the density, and develop a smooth and textured surface from the dense (but scattered) point cloud. The success of our method relies on the proposed optimization framework for accurate motion estimation between two sparse point clouds. Our formulation for fusing it closest-point and it consensus based motion estimations, respectively in the absence and pres…
Dažu metālisko elementu sastopamības variācijas brūklenēs (VACCINIUM VITIS-IDEAEA L.) un augsnē
2020
Darbā ir analizēts tādu metālisko elementu kā Fe, Cu, Zn, K, Mn, Ni, Cd, As un Pb saturs brūklenēs un pētīta to pārnese uz dažādām auga daļām, izsekots arī fosfora koncentrācijai brūklenēs. Augsnes paraugos noteikts pH, dzelzs un cinka saturs. Brūkleņu paraugi un augsne līdz 10 cm dziļumam tika ievākti divās teritorijās: Garkalnes mežs un Vecumu mežs Žīguru pagastā.
Lāzerinducētās sagraušanas spektroskopijas un enerģijas dispersīvās rengenfluoriscences metožu pielietojums zāļu tēju paraugu pētījumos
2022
Lāzerinducētās sagraušanas spektroskopijas un enerģijas dispersīvās rengenfluoriscences metožu pielietojums zāļu tēju paraugu pētījumos. Černiševs R.., darba vadītāji Mg.chem. Bērtiņš M., Dr.sc.ing. Brangule A. Bakalaura darbs, 39 lappuses, 16 attēli, 13 tabulas, 28 literatūras avoti. Latviešu valodā. Darbā tika veikta zinātniskās literatūras izpēte un apkopojums par spektroskopijas metodēm, ko var izmantot ķīmisko elementu kvalitatīvo un kvantitatīvo noteikšanai. Praktiskajā daļā tika veikta zāļu tēju analīze izmantojot rentgenfluoriscences spektroskopiju un lāzerinducētās sagraušanas spektroskopijas metodēm.
Application of LA-ICP-MS as a rapid tool for analysis of elemental impurities in active pharmaceutical ingredients.
2014
The control of inorganic contaminants in active pharmaceutical ingredients has a significant role in the quality control of drug products. The concentration limits for metal residues in drug products have been defined by various regulatory guidelines. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is a powerful and fast analytical technique for multi-elemental analysis. A disadvantage in using LA-ICP-MS method is the lack of matrix reference materials for validation and calibration purposes. This article focuses on the handling strategy of laboratory-made matrix calibration standards for the quantification of elemental impurities in an active pharmaceutical ingredie…
The impact of isolated lesions on white-matter fiber tracts in multiple sclerosis patients
2015
Infratentorial lesions have been assigned an equivalent weighting to supratentorial plaques in the new McDonald criteria for diagnosing multiple sclerosis. Moreover, their presence has been shown to have prognostic value for disability. However, their spatial distribution and impact on network damage is not well understood. As a preliminary step in this study, we mapped the overall infratentorial lesion pattern in relapsing–remitting multiple sclerosis patients (N = 317) using MRI, finding the pons (lesion density, 14.25/cm3) and peduncles (13.38/cm3) to be predilection sites for infratentorial lesions. Based on these results, 118 fiber bundles from 15 healthy controls and a subgroup of 23 …
Neoproterozoic Rosetta Gabbro from northernmost Arabian–Nubian Shield, south Jordan : Geochemistry and petrogenesis
2017
An Ediacaran mafic intrusion of south Jordan is a distinctive appinitic igneous rock with a possibly unique texture, characterized by spherical clots up to 40 mm in diameter composed of amphibole cores from which plagioclase euhedra radiate; we call it the Rosetta Gabbro. It is exposed as a small (ca. 750 m(2)) outcrop in the Neoproterozoic basement of south Jordan. A second outcrop of otherwise similar gabbro is located about 400 m to the north of the Rosetta Gabbro, but it lacks the distinctive texture. The Rosetta Gabbro could represent a magma pipe. It intrudes the Aqaba Complex (similar to 600 Ma) granitoids and metasediments of the Janub Metamorphic Complex (633-617 Ma). The gabbro is…