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1.
A NEW TOOL TO EVALUATE CORTISOL CONCENTRATIONS IN ANIMAL HAIR
Antonella Comin, Tanja Peric, Mara Colzani, Francesco De Vecchi, Cristina Bergamin, Alberto Prandi, 2018, published scientific conference contribution abstract

Abstract: The study of cortisol in hair requires the use of a highly sensitive assay. To date, hair cortisol concentrations (HCC) have been evaluated with different analytical methods as Radio Immune Assay (RIA), Enzyme Immunossay (EIA), Enzyme Linked Immunosorbent Assay (ELISA), ChemiLuminescent Immunoassay (CLIA) and High Performance Liquid Chromatography with Mass Spectrometry (HPLC/MS) or Liquid Chromatography with Tandem Mass Spectrometry (LC-MS/MS). Amplified luminescent proximity homogeneous assay (AlphaLISA) is an ELISA-like, nonradioactive technology first reported in 1994 [1]. This technology allows the quantitative detection of molecules of interest in a light-induced chemiluminescence immunoassay using a microplate without wash step. The aim of the study was to compare RIA with AlphaLISA method and examine the sensitivity in evaluating cortisol concentrations in animal hair of the Cortisol AlphaLISA kit (PerkinElmer, USA), originally suggested for the analysis of buffer and serum samples. The study has been carried out on 4 samples of calf, 4 samples of foal and 8 samples of sheep hair. After washing with isopropanol, two extracts were obtained from each hair sample. One extract has been evaluated for HCC by RIA as previously described [2,3]. The second extract has been reconstituted with the buffer provided by the Cortisol AlphaLISA Kit and HCC evaluated by the use of this commercially available kit. The preliminary results indicate that the Cortisol AlphaLISA Kit is capable to detect cortisol also in hair samples with high sensitivity, with a detection limit of 17 pg/ml. Intra- and inter-assay coefficients of variation (CVs) were 4.0% and 9.0%, respectively. Cortisol concentrations ranged between 1.31 and 16.94 pg/mg, 6.30 and 57.65 pg/mg, and 2.16 and 45.08 in calf, foal and sheep hair, respectively. The HCC obtained by Cortisol AlphaLISA Kit and RIA showed a good correlation (r=0.79, p<0.01). Considering the possibility to use a low amount of extracted sample, its no-washing procedure and the performances showed, we can conclude that the Cortisol AlphaLISA Kit can be considered an excellent tool to evaluate cortisol concentrations also in hair derived from animal species.
Found in: ključnih besedah
Summary of found: ...hair, cortisol, analyses, method, AlphaLISA, Amplified luminescent proximity homogeneous assay...
Keywords: hair, cortisol, analyses, method, AlphaLISA, Amplified luminescent proximity homogeneous assay
Published: 09.04.2019; Views: 1715; Downloads: 0
.pdf Fulltext (4,05 MB)

2.
Photo-Chemically-Deposited and Industrial Cu/ZnO/Al2O3 Catalyst Material Surface Structures During CO2 Hydrogenation to Methanol: EXAFS, XANES and XPS Analyses of Phases After Oxidation, Reduction, and Reaction
Blaž Likozar, Iztok Arčon, Venkata Dasireddy, Maja Pori, 2021, original scientific article

Abstract: Industrial Cu/ZnO/Al2O3 or novel rate catalysts, prepared with a photochemical deposition method, were studied under functional CH3OH synthesis conditions at the set temperature (T) range of 240–350 °C, 20 bar pressure, and stoichiometric carbon dioxide/hydrogen composition. Analytical scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray adsorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) methods were systematically utilized to investigate the interfaces, measured local geometry, and chemical state electronics around the structured active sites of commercially available Cu/ZnO/Al2O3 material or synthesized Cu/ZnO. Processed Cu K-edge EXAFS analysis suggested that various Cu atom species, clusters, metallic fcc Cu, Cu oxides (Cu2O or CuO) and the Cu0.7Zn2 alloy with hexagonal crystalline particles are contained after testing. It was proposed that in addition to the model’s Cu surface area, the amount, ratio and dispersion of the mentioned bonded Cu compounds significantly influenced activity. Additionally, XPS revealed that carbon may be deposited on the commercial Cu/ZnO/Al2O3, forming the inactive carbide coating with Cu or/and Zn, which may be the cause of basicity’s severe deactivation during reactions. The selectivity to methanol decreased with increasing T, whereas more Cu0.7Zn2 inhibited the CO formation through reverse water–gas shift (RWGS) CO2 reduction.
Found in: ključnih besedah
Keywords: CH3OH synthesis, Cu/ZnO-based catalyst, XPS, XANES, EXAFS analyses, Catalyst selectivity and activity
Published: 03.06.2021; Views: 431; Downloads: 0
.pdf Fulltext (3,98 MB)

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