10 research outputs found
Double-Relief Silver Coins Minted in the Greek Colonies (444-390/340-280/270 BC) of Souther Italy Analysed by XRF
No full textA sample of 18 double-relief coins from different poleis of Magna Graecia and ancient Italy has been analysed using a handheld XRF spectrometer directly inside the Museo Provinciale Campano (Capua, Italy). The data analysis shows that (i) the main elements are Ag and Cu, indicating that the coins are of high fineness (average Ag 95.7%), (ii) trace elements can help to characterise the coins, (iii) a superficial chemically altered layer (corrosion) is absent, (iv) the values of ratio Ag Kα/Lα evidence the presence of an enrichment layer on the surface of silver or subaerata in some coins. Multivariate statistical analysis and graph analysis allowed the coins to be assigned to different groups with the highest possible accuracy on the basis of the chemical data obtained and models to be constructed to classify the coins according to their historical periods
Study of ‘Cona degli Ordini’ by Colantonio with IR and XRF Analyses
No full textTwo paintings by the Neapolitan Renaissance painter Colantonio were studied with two non-invasive techniques to enrich the technical–scientific documentation. Infrared reflectography (IR) and x-ray fluorescence (XRF) analyses were performed on Saint Jerome in the studio and Saint Francis delivering the Rule, paintings preserved in the Museo e Real Bosco di Capodimonte. The IR scanning was performed to look beyond the visible layers of the paint for the preparatory drawings and pentimenti, or changes made during the painting process. The XRF technique was applied in many points to determine the elemental composition and enable the identification of pigments and materials used in paint and in the preparatory layers. Elemental XRF mapping was also carried out on a region of particular interest. Results provide an initial overview and hypothesis of color palette and techniques used by the artist
Combination of non-invasive imaging techniques to characterize pigments in Buddhist thangka paintings
No full textInternational audienceScanning macro-XRF, XRF point measurements and hyperspectral reflectance imaging in the visible and near-infrared range were combined to characterize the pigments of a Tibetan painting. The complementary use of the different investigation techniques allowed us to (i) clearly identify the pigments used by the artist, (ii) strengthen the few data present in historical and contemporary sources and (iii) provide data necessary for any accurate conservation treatment of the painting. The proposed methodology allows an in-depth characterization of the materials used in thangkas, with the identification of all the pigments used by Tibetan artists, as shown by the analyses of reference samples. In the present study traditional pigments, commonly cited in historical sources, were identified such as vermilion, minium, orpiment and azurite, but also more unusual compounds such as brochantite and antlerite (in blue/green areas). Elemental distribution images confirmed that some parts of the thangka were restored, without taking into account the original pigments or the original design. Underlying annotations and a carbon black under-drawing were highlighted by the application of near-infrared hyperspectral imaging technique, which proved to be particularly useful for the study of such paintings
Gold‐coating thickness determination on Ag, Cu, Fe, and Pb using a handheld X‐ray instrument
No full textCombining XRF, Multispectral Imaging and SEM/EDS to Characterize a Contemporary Painting
No full textDiagnostic analyses on a contemporary painting on canvas were performed with X-ray fluorescence (XRF), multispectral imaging and scanning electron microscope/energy dispersive spectroscopy (SEM/EDS). The results of each method provided complementary information to deepen the knowledge of the pictorial technique. Multispectral imaging provided insight into the topmost layers. XRF analysis made it possible to characterize the chemical composition of some materials and pigments used by the artist. Additional information such as that relating to canvas preparation emerged with the SEM/EDS technique. The results reveal (i) the use of pre-treated industrial canvas; (ii) the preparatory layer consists of plaster covered with a primer with titanium white, zinc and lithopone; (iii) a layer of cadmium yellow ground was inserted to give depth and three-dimensionality to the painting; (iv) the absence of underlying design; (v) the characterized pigments are all contemporary and (vi) a fixative spray covers the paint
Evolution of the G+C content frontier in the rat cytomegalovirus genome
No full textWithin the 230138 bp of the rat cytomegalovirus (RCMV) genome, the G+C content changes abruptly at position 142644, constituting a G+C content frontier. To the left of this point, overall G+C content is 69.2%, and to the right it is only 47.6%. A region of extremely low G+C content (33.8%) is found in the 5 kb immediately to the right of the frontier, in which there are no predicted coding sequences. To the right of position 147501, the G+C content rises and predicted coding sequences reappear. However, these genes are much shorter (average 848bp, 50% G+C) than those in the left two-thirds of the genome (average 1462bp, 70% G+C). Whole genome alignment of several viruses indicates that the initial ultra-low G+C region appeared in the common ancestor of the genera Cytomegalovirus and Muromegalovirus, and that the lowering of G+C in the right third has been a subsequent process in the lineage leading to RCMV. The left two-thirds of RCMV has stop codon occurrences at 67.5% of their expected level, based on a modified Markov chain model of stop codon distribution, and the corresponding figure for the right third is 78%. Therefore, despite heavy mutation pressure, selective constraint has operated in the right third of the RCMV genome to maintain a degree of gene length unusual for such low G+C sequences
Combining Multispectral Imaging and XRF Analysis to Examine San Patroba predica ai fedeli di Pozzuoli by Massimo Stanzione
No full textA diagnostic analysis of the painting depicting San Patroba che predica ai fedeli di Pozzuoli by Massimo Stanzione was carried out. The painting was completed in 1635–1637 to decorate the choir of the Cathedral of Saint Procolo in Pozzuoli (Naples, Italy). The technique of X-ray fluorescence (XRF) and multispectral imaging were applied on site to learn about the executive technique, the palette of the painting, and the restoration works, as well as understand the influence of the other painters active in Naples in that period. The results of the research are presented and discussed to draw general aspects and peculiarities of the pigments and the pictorial technique used by this important painter, as well as the restorations
Tocilizumab for patients with COVID-19 pneumonia. The single-arm TOCIVID-19 prospective trial
No full textBackgroundTocilizumab blocks pro-inflammatory activity of interleukin-6 (IL-6), involved in pathogenesis of pneumonia the most frequent cause of death in COVID-19 patients.MethodsA multicenter, single-arm, hypothesis-driven trial was planned, according to a phase 2 design, to study the effect of tocilizumab on lethality rates at 14 and 30 days (co-primary endpoints, a priori expected rates being 20 and 35%, respectively). A further prospective cohort of patients, consecutively enrolled after the first cohort was accomplished, was used as a secondary validation dataset. The two cohorts were evaluated jointly in an exploratory multivariable logistic regression model to assess prognostic variables on survival.ResultsIn the primary intention-to-treat (ITT) phase 2 population, 180/301 (59.8%) subjects received tocilizumab, and 67 deaths were observed overall. Lethality rates were equal to 18.4% (97.5% CI: 13.6-24.0, P=0.52) and 22.4% (97.5% CI: 17.2-28.3, P<0.001) at 14 and 30 days, respectively. Lethality rates were lower in the validation dataset, that included 920 patients. No signal of specific drug toxicity was reported. In the exploratory multivariable logistic regression analysis, older age and lower PaO2/FiO2 ratio negatively affected survival, while the concurrent use of steroids was associated with greater survival. A statistically significant interaction was found between tocilizumab and respiratory support, suggesting that tocilizumab might be more effective in patients not requiring mechanical respiratory support at baseline.ConclusionsTocilizumab reduced lethality rate at 30 days compared with null hypothesis, without significant toxicity. Possibly, this effect could be limited to patients not requiring mechanical respiratory support at baseline.Registration EudraCT (2020-001110-38); clinicaltrials.gov (NCT04317092)
