Chemical modification of wood induced by the traditional making procedures of bowed string musical instruments: the effect of alkaline treatments

Over the last few decades, chemical and physical studies on bowed string musical instruments have provided a better understanding of their wooden finished surface. Nevertheless, until now only a few of them investigated the effects of the chemical pre-treatments in the traditional making procedures. Those treatments are believed to affect wood properties, its interaction with the following treatments (i.e. varnish application) and its vibro-mechanical behaviour (that may contribute to the acoustical properties of musical instruments). In this study, two traditional alkaline treatments were applied to reference samples of spruce wood, the wood commonly used to make violins’ soundboards. An integrated analytical strategy, which combines infrared spectroscopy, analytical pyrolysis coupled to gas chromatography-mass spectrometry, and gel permeation chromatography, was employed to investigate the chemical alterations of lignocellulosic polymers (cellulose, hemicellulose, and lignin). Results have shown that the selected alkaline treatments induce the partial hydrolysis of the hemicellulose chains and a slight decrease in the crystallinity of cellulose. We could also prove: (i) the cleavage of lignin-carbohydrate complexes formed by the covalent bonds between hemicellulose and lignin in spruce wood, and (ii) the partial breaking of the hydrogen bonds network in cellulose. According to the literature, the alteration of the lignin-carbohydrate complexes is responsible for changes in wood mechanical behaviour. Hence, future perspectives of this research could outline new knowledge on the vibro-mechanical behaviour of the violin soundboard and the consequent acoustics

Characterisation of archaeological waterlogged wood by pyrolytic and mass spectrometric techniques

1) Department of Chemistry and Industrial Chemistry, University of Pisa, via Risorgimento 35. 56126 Pisa, Italy ; 2) IRNAS-CSIC, Seville, Spain; E-mail address: [email protected] combination of two techniques based on analytical pyrolysis and mass spectrometry, including direct exposure-MS (DE-MS) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), was used to study the chemical composition of waterlogged archaeological wood. In particular, the two techniques were used to chemically characterise samples of archaeological wood from the excavation of the Site of the Ancient Ships of Pisa San Rossore in Pisa (Italy). The data were compared to those of native sound wood of the same species. The results highlight that DE-MS is a valuable technique for the characterisation of archaeological wood. DE-MS allows us to use a minimal sample size and to perform the analysis in a few minutes, thus avoiding the long wet-chemical procedures that are commonly used to characterise wood. The results also confirm the importance of Py-GC/MS as a tool for shedding light on the chemical modifications of wood in archaeological objects. The analyses demonstrated that waterlogged wood from the site of Pisa San Rossore have undergone an extensive loss of polysaccharides together with partial demethylation of lignin units, both guaiacyl and syringyl monomers. In fact, catechols and methoxy catechols were identified among the pyrolysis products of the waterlogged wood samples.The authors wish to thank Dott.ssa G. Giachi (Restoration Laboratories of the Archaeological Superintendence of Tuscany, Florence, Italy) for providing archaeological wood samples and for her valuable support and collaboration. Funding was provided by the Archaeological Superintendence of Tuscany and by the Italian MIUR (PRIN Cofin05).Peer reviewe

Advancements in the chemical structures of Ergot acyl glycerides by high performances liquid chromatography coupled with high resolution mass spectrometry

A comprehensive picture of the chemical composition and structure of the acyl-glycerides from ergot (fungi of the genus Claviceps) sclerotia was carried out using liquid chromatography coupled with high resolution mass spectrometry (HPLC-ESI-Q-ToF) following microwave solvent extraction. The method allowed us to study the chemical structures of >70 compounds being most of these reported and characterized here for the first time in ergot sclerotia. Diglycerides, triglycerides and estolides were proper preliminary separated using reverse phase chromatography and the unambiguous chemical structure of each species was characterized using high resolution tandem mass spectrometry. Our data and results could be useful for anyone interested in detecting ergot contaminations in cereals and deriving products, as alternative to the identification of alkaloids, in better understanding the behavior of ergot fungi in biological contest and in evaluating the potential uses of ergot estolides in industrial applications

Characterisation of archaeological waterlogged wood by pyrolytic and mass spectrometric techniques

A combination of two techniques based on analytical pyrolysis and mass spectrometry, including direct exposure-MS (DE-MS) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), was used to study the chemical composition of waterlogged archaeological wood. In particular, the two techniques were used to chemically characterise samples of archaeological wood from the excavation of the Site of the Ancient Ships of Pisa San Rossore in Pisa (Italy). The data were compared to those of native sound wood of the same species. The results highlight that DE-MS is a valuable technique for the characterisation of archaeological wood. DE-MS allows us to use a minimal sample size and to perform the analysis in a few minutes, thus avoiding the long wet-chemical procedures that are commonly used to characterise wood. The results also confirm the importance of Py-GC/MS as a tool for shedding light on the chemical modifications of wood in archaeological objects. The analyses demonstrated that waterlogged wood from the site of Pisa San Rossore have undergone an extensive loss of polysaccharides together with partial demethylation of lignin units, both guaiacyl and syringyl monomers. In fact, catechols and methoxy catechols were identified among the pyrolysis products of the waterlogged wood samples

Correction: Hafting of Middle Paleolithic tools in Latium (central Italy): New data from Fossellone and Sant’Agostino caves(PLoS ONE (2019)14:6(e0213473) DOI: 10.1371/journal.pone.0213473)

An incorrect version of Fig 1 was published in error. Additionally, a Supporting Information file was incorrectly included in the originally published article. The publisher apologizes for these errors. This article was republished on September 27, 2019 to correct for these errors. Please download this article again to view the correct version

The Ploutonion of the Archaeological Site of Hierapolis (Turkey): A Gate for the Underworld and the Knowledge

The archaeological site of Hierapolis (Denizli, Turkey), one of the great Hellenistic, Roman and Byzantine cities of southwestern Turkey, protected by UNESCO since 1988, was built in the third century B.C. Even if damaged several times by earthquakes, it has survived for millennia. During antiquity, Hierapolis was a famous pilgrimage destination, the centre of a cult, because of the Ploutonion, the sanctuary dedicated to Hades– Pluto and his wife Kore–Persephone, visited also by Cicero and Strabo. In this paper the authors report the results obtained on some materials found in recent excavations carried out in the Ploutonion area. In particular, the investigated materials were a marble bust, a fragment of marble slab with painted scales and a piece of resin. Non-invasive (i.e. imaging techniques and portable X-Ray Fluorescence) and micro-destructive (i.e. X-Ray Diffraction, Fourier Transform Infrared spectroscopy, High-Performance Liquid Chromatography coupled to a Mass Spectrometry detector and Pyrolysis coupled with Gas Chromatography/Mass Spectrometry) have been employed to characterize the archaeological finds

Effects of low sulfur dioxide concentrations on bioactive compounds and antioxidant properties of Aglianico red wine

This study analyzed the effect of low sulfur dioxide concentrations on the chromatic properties, phytochemical composition and antioxidant activity of Aglianico red wines with respect to wines produced from conventional winemaking. We determined the phytochemical composition by spectrophotometric methods and HPLC-DAD analysis and the in vitro antioxidant activity of different wine samples by the ORAC assay. The main important classes of fluorophore molecules in red wine were identified by Front-Face fluorescence spectroscopy, and the emission intensity trend was investigated at various sulfur dioxide concentrations. Lastly, we tested the effects of both conventional and low sulfite wines on ex vivo human erythrocytes under oxidative stimulus by the cellular antioxidant activity (CAA) assay and the hemolysis test. The addition of sulfur dioxide, which has well-known side effects, increased the content of certain bioactive components but did not raise the erythrocyte antioxidant capacity

Indian Ocean trade connections: characterization and commercial routes of torpedo jars

During the Classical Period (300 BC–400 AD), the Indian Ocean emerged as one of the largest hubs of ancient international trade. For a long period, these contacts were described from a Rome-centric point of view, looking at the connections between Rome and India. However, recent studies have demonstrated that the Roman-Indo connection was only one of the vast medium and short distance trade routes involving numerous regions and populations, exchanging goods and culture. Current archaeological investigations have demonstrated that several minor trade dynamics formed the primary connective tissue of the Indian Ocean. This study attempts to trace these mid-range connections by focusing on the transport of torpedo jars, recently found in several settlements throughout the Indian Ocean. Two archaeological sites were considered: Al Hamr al-Sharqiya 1 (Inqitat, southern Oman), and the port of Alagankulam (southern India). An analytical protocol based on thin sections analysis, SEM–EDS, XRD and GC/MS was applied to a selection of fragments from the two archaeological sites. The analytical investigation carried out on these vessels identified three different ceramic compositions, which distributed differently in the two sites, characterized by a black coating due to a similar bitumen source. The location of the production sites and comparative studies between these vessels and reference materials available in the literature enabled us to cast new light on the routes followed by the torpedo jars, from Mesopotamia to India and Oman