La conservazione preventiva del patrimonio librario come possibile alternativa al restauro tradizionale

The present paper focuses on the close relation between library collections and their preservation environment, aiming, in particular, at highlighting the importance of promoting and sustaining the monitoring. The paper proposes some simple and ready-to-use technologies – smart monitoring – to prevent future damages

Exploring the potential of pyrolysis-comprehensive two-dimensional gas chromatography/mass spectrometry in the characterization of Chinese inks of ancient manuscripts

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Understanding carbonaceous deposit formation resulting from engine oil degradation

International audienceThe formation processes of carbonaceous deposits in the first piston ring grooves of direct injection diesel engines have been studied. Deposits generated during engine tests were analysed by SEM/EDX, thermogravimetric analysis, pyrolysis/gas chromatography/mass spectrometry, and FT-IR spectroscopy. These analyses showed that the deposits, with a structure of cracked varnishes, mainly resulted from the degradation of lubricants. Their state strongly depends on the severity of the tests, which resulted in the formation of two kinds of deposits, termed as 'oily' and 'dry', according to their content of volatile organic matters. Then, to better understand the deposit formation process, a thermo-oxidative degradation of the lubricating oil was carried out in a tubular furnace, while varying temperature, duration of the test, and adding metallic elements to simulate the engine wear. The consumption of antioxidant additives and the lubricant carbonization were highlighted. Temperature level was identified as the most influential parameter during the lubricant degradation process. The presence of metallic elements appeared to act as a catalyst by speeding up the degradation when the tests duration was increased. Cop. 2008 Elsevier Ltd. All rights reserved

Molecular criteria for discriminating museum Asian lacquerware from different vegetal origins by pyrolysis gas chromatography/mass spectrometry.

International audienceThis paper focuses on the identification of several chemical markers of vegetal species of Oriental lacquers with the aim at providing a methodology consistent with sampling restrictions necessarily applied in the field of cultural heritage. The method proposed is based on rapid and easy single step thermally assisted hydrolysis-methylation (THM) pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) analysis that can be carried out with a minimum amount of matter (typically 10 μg for a sample collected on a museum or an archaeological object). The main contribution of this study is to provide multiple molecular criteria for discriminating the three Asian species used for making lacquers, namely Rhus verniciflua Stokes, Rhus succedanea and Melanorrhoea usitata. Because these trees grow in specific areas, identifying the species involved in ancient lacquer coatings also provides geobotanical data and fruitful information on the exchange networks and trading routes developed by ancient societies. With this purpose, a systematic study of all pyrolysis products of lacquer coatings was carried out on modern dried lacquer films from authentified provenance. It was demonstrated that the whole pyrolysis products play a significant role in identifying the vegetal species. The chemotaxonomic value of homologous series of alkanes, alkenes and benzene derivatives, rarely explored until now, was assessed. It was shown that the combination of data related to five distinct groups of pyrolytic markers (composition and/or distribution of alkanes, alkenes and benzene, alkenyl-, alkylcatechol and phenol derivatives) provided new strong criteria to establish vegetal origin and provenance of Asian artworks, even though they have been largely altered over time. Case studies of archaeological Chinese lacquered artefacts and Japanese Buddhistic altar were thereafter successfully investigated to address informative potential and efficiency of these criteria on ancient and degraded lacquer coatings. Copyright © 2011 Elsevier B.V. All rights reserved

Optimization of an Assay To Determine Colonization Resistance to Clostridioides difficile in Fecal Samples from Healthy Subjects and Those Treated with Antibiotics

A healthy, intact gut microbiota is often resistant to colonization by gastrointestinal pathogens. During periods of dysbiosis, however, organisms such as Clostridioides difficile can thrive. We describe an optimized in vitro colonization resistance assay for C. difficile in stool (CRACS) and demonstrate the utility of this assay by assessing changes in colonization resistance following antibiotic exposure. Fecal samples were obtained from healthy volunteers (n = 6) and from healthy subjects receiving 5 days of moxifloxacin (n = 11) or no antibiotics (n = 10). Samples were separated and either not manipulated (raw) or sterilized (autoclaved or filtered) prior to inoculation with C. difficile ribotype 027 spores and anaerobic incubation for 72 h. Different methods of storing fecal samples were also investigated in order to optimize the CRACS. In healthy, raw fecal samples, incubation with spores did not lead to increased C. difficile total viable counts (TVCs) or cytotoxin detection. In contrast, increased C. difficile TVCs and cytotoxin detection occurred in sterilized healthy fecal samples or those from antibiotic-treated individuals. The CRACS was functional with fecal samples stored at either 4°C or −80°C but not with those stored with glycerol (12% or 30% [vol/vol]). Our data show that the CRACS successfully models in vitro the loss of colonization resistance and subsequent C. difficile proliferation and toxin production. The CRACS could be used as a proxy for C. difficile infection in clinical studies or to determine if an individual is at risk of developing C. difficile infection or other potential infections occurring due to a loss of colonization resistance