Search results for "Varnish"
showing 8 items of 38 documents
Analytical characterization of diterpenoid resins present in pictorial varnishes using pyrolysis–gas chromatography–mass spectrometry with on line tr…
2005
Abstract A procedure based on the technique of the pyrolysis–gas chromatography–mass spectrometry (Py–GC–MS) has been applied, in this work, in order to determine the composition of diterpenoid resin employed in art works. The method is based on the on line derivatization of these resins using hexamethyldisilazane (HMDS). Results obtained were compared with those previously reported in literature from Venice turpentine, Strasbourg turpentine, colophony, sandarac and Manila copal using this same method and with those others from in situ thermally assisted hydrolysis and methylation with tetramethylammonium hydroxide (TMAH). Canada balsam, copper resinate and Copaiba balsam have been also ana…
Ex vivo study of bacterial coronal leakage in indirect pulp treatment
2012
Objective: The aim of this study was to evaluate, ex vivo, bacterial coronal leakage with different antimicrobial agents applied to the dentine for indirect pulp treatment (IPT). Study Design: Sixty extracted teeth were prepared and randomly distributed into 5 groups (n=10): Group 1: no antimicrobial dentine treatment; group 2: 1% chlorhexidine (CHX)+1% thymol varnish (Cervitec®); group 3: 2 % CHX solution; group 4: 40% CHX varnish (EC40™) and group 5: Clearfil™ Protect Bond (CPB). Ten teeth served as controls. The teeth were restored using a resin-modified glass ionomer cement (GIC) and then mounted in a two-chamber device. The coronal access was exposed to Streptococcus mutans for 45 days…
Gas chromatography-mass spectrometry characterization of the varnish and glue of an ancient 18th century double bass.
2007
A GC–MS investigation is conducted on the double bass “Panormus”, property of Conservatorio di Musica “Vincenzo Bellini” in Palermo. The most important components of the varnish (fatty acids) and of the glue (proteinaceous amino acids), with which the musical instrument was treated in the past, are determined. The analyses are carried out by prior derivatization of fatty acids by acidic methanol and of amino acids by acidic methanol and trifluoroacetic anhydride (TFAA). Analytes identification is achieved by direct comparison with several reference materials and the use of a digitized library.
Topical Fluoride for Preventing Dental Caries in Children and Adolescents
2012
The use of topically applied fluoride has been widely researched as a means to reduce the risk of dental caries in conjunction with other treatment modalities (mechanical oral hygiene, dietary control, antimicrobial intervention, pit and fissure sealants). There is overwhelming evidence that reports not only the significance and importance of the use of fluoride as a caries-preventive agent, but also how safe fluoride application is when used appropriately, particularly in higher risk individuals and populations. This paper reviews the caries-protective benefits of topical fluoride application in children and adolescents, with an emphasis on the clinical efficacy and safety of the vehicles …
La torre del Tempo: il punto di vista del chimico
2013
L’obiettivo del presente lavoro è stato quello di valutare la tipologia di lega metallica, il suo degrado e la tipologia di vernice dell’opera in ferro policroma “La Torre del Tempo” di E. Tadini. A tale scopo sono state effettuate delle misure di Microscopia Ottica, Diffrattometria a raggi X, Spettroscopia micro-Raman e Spettroscopia NMR. The goal of this study was to evaluate the type and the of conservation state of the metal alloy and the type of varnish of samples coming from “La Torre del Tempo” E. Tadini. The samples were characterized by Optical Microscopy, X-ray Diffractometry, micro-Raman Spectroscopy and NMR spectroscopy.
Ageing behaviour and analytical characterization of the Jatobá resin collected from Hymenaea stigonocarpa Mart.
2009
Abstract This paper reports the results of an analytical study to characterize the trunk resin collected from the Hymenaea stigonocarpa Mart. species from the region of Minas Gerais (Brazil), popularly known as Jatoba resin. Hymenaea resins are reported to have been used in artistic applications such as protective varnishes in polychromed sculptures and paintings. Therefore, the identification of the main chemical changes that take place in the resin when it is prepared as a thin film exposed to atmospheric effects have been considered herein. Changes due to the degradation effect of light have been studied on a series of specimens prepared as a thin films and subjected to accelerated UV li…
Gas chromatography/mass spectrometry characterization of historical varnishes of ancient Italian lutes and violin
2007
The organic constituents of historical vanishes from two ancient Italian lutes and a Stradivari violin, kept in the Musée de la musique in Paris, have been characterized using gas chromatography-mass spectrometry. Results have been compared with the chromatograms and mass spectra of recent as well as old naturally aged reference materials. The three historical varnishes analyzed have been shown to be oil varnishes, probably mixtures of linseed oil with resins. Identification of diterpenoids and triterpenoids compounds, and of the resins that may have been ingredients of the varnishes, are discussed in this paper.
Micro-X-Ray Fluorescence and the Old Masters Non-destructive in situ characterisation of the varnish of historical Low Countries stringed musical ins…
2012
Applied Physics A, 107