Search results for " Spectroscopy"
showing 10 items of 6851 documents
Identification of Bioactive Compounds in Polar and Nonpolar Extracts of Araujia sericifera
2017
Abstract Araujia sericifera is a native perennial, climbing laticiferous shrub from South America that is currently naturalized in many other countries. Previous data describe promising properties for A. sericifera, but no systematic study of its bioactive compounds and possible medicinal applications has been conducted to date. In the present study, aerial parts of A. sericifera (leaves, stems, and fruits) were explored by combining GC-MS and NMR spectroscopy analysis for both nonpolar (hexane) and polar (methanol) extracts. The hexanic extracts contained high amounts of pentacyclic triterpenes including two new metabolites, 3-tigloyl germanicol (18) and 3-tigloyl lupeol (19). The methanol…
Multi-analytical study of the medieval wall paintings from the rupestrian church Grotta del Crocifisso at Lentini (eastern Sicily): new evidence of t…
2022
AbstractThis study presents the results of the examination and characterisation of the wall paintings that decorate the rupestrian church named Grotta del Crocifisso, which is located in the territory of Lentini (eastern Sicily, few tens of kilometres from Catania and Syracuse). The earliest mural paintings in the church date back to the twelfth century AD. A multi-analytical approach was adopted for the characterisation of stone materials, secondary degradation products, and pigments. For this purpose, the following techniques were used: reflected light microscopy (RLM), polarised light microscopy on thin sections (PLM), X-ray powder diffraction (XRPD), mercury intrusion porosimetry (MIP),…
PHYSICO-CHEMICAL CHARACTERIZATION OF THE ACQUALADRONE ROSTRUM
2011
The archaeological discovery of the Acqualadrone rostrum (an offensive naval weapon mounted on the prow at the waterline), off the Italian coast near Messina in 2008, has led to the need for scientific research in order to plan the conservation treatment of this artefact. The discovery is exceptional because of the presence of a wooden section from the original ship. This paper describes the physico-chemical characterization of a metallic and two wooden samples by inductively coupled plasma – optical emission spectroscopy, inductively coupled plasma – mass spectrometry, Fourier transform infrared spectroscopy, 13 C{ 1 H} cross-polarization magic angle spinning NMR spectroscopy, energy-dispe…
CORRELATION BETWEEN SPECTRAL, SEM/EDX AND ELECTROCHEMICAL PROPERTIES OF MAYA BLUE: A CHEMOMETRIC STUDY*
2009
Visible spectra, composition from SEM/EDX and solid-state electrochemical data are correlated for a set of 12 Maya Blue samples from different archaeological sites of Campeche and Yucatan (Mexico). In addition to indigo and dehydroindigo, indirubin and other possibly indigo-type compounds can be detected in Maya Blue samples. Application of hierarchical cluster analysis techniques allows similarity relationships to be established between samples from different sites, confirming prior results which suggest that the preparation of Maya Blue pigment evolved with time during the Maya culture following a ramified scheme.
The Protohistoric sword from Le Gué-de-Velluire (Vendée, France): a pasticcio's history unveiled by archaeometrical research
2020
International audience; The Gué-de-Velluire sword (Vendée, France) is part of the Rochebrune collection collected during the 19 th and the 20 th centuries and now preserved in the Dobrée Museum in Nantes (Loire-Atlantique, France). The unusual shape of its hilt, its uncorroded rivets and the rather uncommon combination of a bronze grip with an iron blade made this sword an exceptional object. It has been depicted in a large number of papers since the 20 th century, but the question of its authenticity has hardly ever been tackled. New analyses performed with the support of the Dobrée Museum, the Arc'Antique laboratory and Ghent University delivered new data enabling us to discuss this delic…
The blue enamels in the baroque decorations of the churches of Palermo, Sicily: Fe2+-coloured glasses from lime kilns
2009
Deep blue glasses coloured by octahedral Fe 2+ cations are often reported as textbook examples of blue pigmentation. However, despite the possibility of laboratory synthesis under reducing conditions, to date there are no well-reported occurrences of their production and use in the past. A thorough historical, ethnographic, mineralogical, and chemico-physical investigation of the 'smaltini di calcara' from several baroque churches in Palermo, Sicily, has revealed that the blue enamels widely used for altar decorations in the 17th and 18th centuries are actually a unique case of ancient blue glasses pigmented by divalent iron cations in distorted octahedral coordination. This mixed-alkali gl…
Electrochemical Fingerprint of Archeological Lead Silicate Glasses Using the Voltammetry of Microparticles Approach
2016
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Characterization of Iranian Moarraque glazes by light microscopy, SEM-EDX and voltammetry of microparticles
2008
Abstract Glazed ceramics have been traditionally used in Iran for decorating mosques and some civil historical buildings. In particular, Moarraque glazes have been extensively used in the indoor and outdoor decoration of mosques in Iran since the middle 14th century. The pieces have a complex elaboration based on a main glazed piece corresponding to the skeleton structure of the Shah Abbasi flower, which contains a number of holes, where are placed, mosaic-like, smaller glazed pieces forming a compact and single tile. The present work describes the analytical study performed on the glazes of several pieces of Moarraque tiles from the Ali Ebn Abi Taleb Mosque (Esfahan, Iran), which date back…
Spectroscopic analysis used to uncover the original paint colour of the Helsinki Government Palace tower clock faces
2016
The paint stratigraphy of the two clock faces from the tower clock of the Government Palace in Helsinki (Finland) was analysed in order to determine their original colour before restoration works. Paint cross-section samples from both clock faces were analysed by confocal Raman microscopy and scanning electron microscopy coupled to an energy dispersive X-ray spectrometer (SEM-EDS). The results revealed the complex superimposition of paint layers applied over the original black colour. FTIR/ATR analyses proved that the original paint was prepared with linseed oil-resin media. Most likely not all of the different layer colours were visible. Some of the layers were likely to have been a primer…
Analyzing chemical changes in verdigris pictorial specimens upon bacteria and fungi biodeterioration using voltammetry of microparticles
2017
[EN] It is reported the application of the voltammetry of microparticles (VMP), complemented with attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and field emission scanning electron microscopy (FESEM) techniques, to monitor the deterioration of verdigris pictorial specimens under the action of different biological agents. This methodology would be of application for identifying the type of biological agent causing deterioration of paintings, which is an important problem affecting cultural heritage. The analysis of biodeterioration processes is complicated by the fact that the action of microorganisms can affect both pigment and binding media. The deteriorat…