Search results for "PXR"
showing 7 items of 7 documents
Obsidian from the Site of Piano dei Cardoni, Ustica (Palermo, Italy): Preliminary Results on the First Occupation of the Island
2021
Abstract New investigations on Ustica (Palermo, Sicily) originated from the need to improve our knowledge of the island’s archaeological and environmental heritage. Through field surveys, particular attention was paid to human occupation in the Neolithic phases and focused on the less investigated southern side of the island. The systematic survey of the area of Piano dei Cardoni in 2018 brought to light a new Middle/Late Neolithic site, already partially documented in the literature. The island was settled for the first time during these phases, as also testified from the area of Punta Spalmatore. The presence of Serra d’Alto, incised dark burnished, and Diana styles suggests that the site…
Polyoxypregnanes as safe, potent, and specific ABCB1-inhibitory pro-drugs to overcome multidrug resistance in cancer chemotherapy in vitro and in vivo
2021
Multidrug resistance (MDR) mediated by ATP binding cassette subfamily B member 1 (ABCB1) is significantly hindering effective cancer chemotherapy. However, currently, no ABCB1-inhibitory drugs have been approved to treat MDR cancer clinically, mainly due to the inhibitor specificity, toxicity, and drug interactions. Here, we reported that three polyoxypregnanes (POPs) as the most abundant constituents of Marsdenia tenacissima (M. tenacissima) were novel ABCB1-modulatory pro-drugs, which underwent intestinal microbiota-mediated biotransformation in vivo to generate active metabolites. The metabolites at non-toxic concentrations restored chemosensitivity in ABCB1-overexpressing cancer cells v…
El prestigio de los objetos: mangos de marfil en el mundo ibérico
2020
El estudio se centra en una serie de mangos de marfil de características morfotécnicas similares, recuperados en espacios de hábitat y funerarios ibéricos y datados entre el s. IV y el s. II a. C. Se trata de objetos de prestigio al alcance de una élite aristocrática, que han sido elaborados con materias primas exóticas (marfil) y técnicas decorativas inusuales que indican una especialización. A través de análisis de composición por infrarrojo cercano por Transformada de Fourier (FT-NIR) y de fluorescencia de rayos X (pXRF) se ha podido documentar la presencia de incrustaciones de ámbar adheridas a la superficie de los mangos mediante el uso del estaño como soldadura blanda y el empleo de a…
Analysis of Sagunto Ibero-Roman votive bronze statuettes by portable X-ray fluorescence
2019
Abstract The main objective of this work was the study of chemical composition of an important collection of Ibero-Roman votive bronze statuettes exposed in the Archaeological Museum of Sagunto (Spain). Precision and accuracy of the measurements were obtained developing a proper analytical method, also avoiding any possible damage to the studied objects using a portable energy dispersive X- ray fluorescence system. Principal Components Analysis (PCA) to discriminate between groups based on ratios Fe/Cu, Pb/Cu, Sn/Cu, Ag/Cu, Ni/Cu and Impurities/Cu were employed to observe differences between the used smelting, manufacturing processes and raw materials. The characterisation of bronze statuet…
Garcinoic acid prevents β-amyloid (Aβ) deposition in the mouse brain
2020
Garcinoic acid (GA or δ-T3-13'COOH), is a natural vitamin E metabolite that has preliminarily been identified as a modulator of nuclear receptors involved in β-amyloid (Aβ) metabolism and progression of Alzheimer's disease (AD). In this study, we investigated GA's effects on Aβ oligomer formation and deposition. Specifically, we compared them with those of other vitamin E analogs and the soy isoflavone genistein, a natural agonist of peroxisome proliferator–activated receptor γ (PPARγ) that has therapeutic potential for managing AD. GA significantly reduced Aβ aggregation and accumulation in mouse cortical astrocytes. Similarly to genistein, GA up-regulated PPARγ expression and apolipoprote…
Disordered sodium alkoxides from powder data: crystal structures of sodium ethoxide, propoxide, butoxide and pentoxide, and some of their solvates
2021
The crystal structures of NaOEt, NaOPr, NaOBu and NaOAm (Am = amyl = pentyl) were determined from powder data. These compounds crystallize in an anti-PbO structure in the space groups P 21 m and P4/nmm. Additionally, solvates with the composition NaOEt·2EtOH, NaOPr·2PrOH, NaOiPr·5iPrOH and NaOtAm·tAmOH were synthesized, and their structures were determined from single crystals. They form interesting chain structures of different compositions and topologies.
Cēlmetālu piemaisījumu analīze un uzkrāšanās cēloņi tritiju ģenerējošā keramikā
2017
Cēlmetālu piemaisījumu analīze un uzkrāšanās cēloņi tritiju ģenerējošā keramikā. Valtenbergs O., zinātniskais vadītājs: profesors, Dr. chem. Vīksna A., zinātniskais konsultants: pētnieks, MSc. chem. Zariņš A. Maģistra darbs, 40 lappuses, 27 attēli, 6 tabulas, 31 literatūras avots, 4 pielikumi. Latviešu valodā. Literatūras apskatā ir izklāstīta galvenā informācija par kodoltermisko sintēzi un eksperimentālo reaktoru (International Thermonuclear Experimental Reactor – ITER), kā arī tā testa blanketa moduļiem, tritija ģenerējošo keramiku un pētījumam izmantotajām analīzes metodēm. Ar dažādām analīzes metodēm, eksperimentāli tika analizētas modificētās litija ortosilikāta (Li4SiO4) minilodītes …