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Rizzi V.,University of Bari | Losito I.,University of Bari | Losito I.,Centro Interdipartimentale | Ventrella A.,University of Bari | And 8 more authors.
Physical Chemistry Chemical Physics | Year: 2015

The photoreactivity of 4-thiothymidine (S4TdR) under visible light in the presence of Rose Bengal (RB), acting as a photosensitizer, was investigated in aqueous solutions at pH 7 and 12, using UV-vis, FTIR-ATR and 1H-NMR spectroscopic techniques, time resolved absorption spectroscopy and electrospray ionization mass spectrometry (ESI-MS). Evidence for the generation of thymidine (TdR) as the main product, after one hour of irradiation, was obtained from UV-Vis data, that suggested 4-thiothymidine photodegradation to be faster at basic pH, and confirmed by FTIR-ATR and 1H-NMR data. Clues for the presence of a further product, likely corresponding to a dimeric form of S4TdR, were obtained from the latter techniques. Besides indicating the presence of thymidine, the ESI-MS and MS/MS spectra of the reaction mixtures enabled the identification of the additional product as a S-S bridged covalent dimer of 4-thiothymidine. The concentration of the dimeric species could be estimated with the aid of 1H-NMR data and was found to be lower than that of thymidine in pH 7 reaction mixtures and almost negligible in the pH 12 ones. From a mechanistic point of view, time-resolved absorption spectroscopy measurements provided direct evidence that the formation of the two products cannot be ascribed to a photoinduced electron transfer involving S4TdR and the excited triplet state of RB. Rather, their generation can be interpreted as the result of a bimolecular reaction occurring between singlet state oxygen (1O2), photogenerated by RB, and S4TdR, as demonstrated by the direct detection of 1O2 through IR luminescence spectroscopy. More specifically, a sequential reaction pathway, consisting in the generation of an electrophilic hydroxylated form of S4TdR and its subsequent, rapid reaction with S4TdR, was hypothesized to explain the presence of the S-S bridged covalent dimer of 4-thiothymidine in the reaction mixtures. The described processes make S4TdR an interesting candidate in the role of molecular probe for the detection of 1O2 under different pH conditions. This journal is © the Owner Societies.

Calvano C.D.,University of Bari | Calvano C.D.,Centro Interdipartimentale | De Ceglie C.,University of Bari | De Ceglie C.,Centro Interdipartimentale | And 4 more authors.
Food Chemistry | Year: 2012

The adulteration of extra virgin olive oil (EVOO) with hazelnut oil (HO) is frequent and constitutes a serious concern both for oil suppliers and consumers. The high degree of similarity between the two oils as regards triacylglycerol, total sterol and fatty acid profile, complicates the detection of low percentages of HO in EVOO. However, phospholipids (PLs) are usually present in seed oils at a concentration range of 10-20 g/kg, while the amounts of PLs in VOOs are 300-400 times lower. Thus, in this work a sample pretreatment procedure focused towards the selective PLs extraction was developed; the Bligh-Dyer extraction procedure was modified introducing the ionic liquid resulting from the combination of TBA (tributylamine) and CHCA (α-Cyano-4-hydroxycinnamic acid) as extraction solvent. The selective extraction and enrichment of phospholipids from EVOO and HO samples was then achieved. The relevant extracts were analyzed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) using the same ionic liquid TBA-CHCA as MALDI matrix, that was found to be very suitable for PLs analysis. In fact, a remarkable increase of the phospholipids signals, with a simultaneous decrease of those relevant to triacylglycerols and diacylglycerols, was observed in the relevant mass spectra. The applicability of the whole method to the individuation of the presence of HO in EVOO was demonstrated by the analysis of EVOO samples progressively adulterated with variable quantities of HO, that was still detectable at a 1% contamination level. © 2012 Elsevier Ltd. All rights reserved.

Giannossa L.C.,University of Bari | Acquaviva M.,University of Bari | De Benedetto G.E.,University of Salento | Acquafredda P.,University of Bari | And 5 more authors.
Analytical Methods | Year: 2014

This study focuses on defining compositional and structural characteristics, identifying raw materials and production technology, and validating the archaeological hypothesis of a local production of thin-walled pottery (2nd cent. BC-3rd cent. AD) in the Vesuvian area. Samples investigated were analysed using OM, SEM-EDS, XRD and LA-ICPMS supported by a statistical multivariate treatment of the compositional data of the ceramic bodies. The results obtained show how an integrated approach of analytical techniques can provide answers to archaeological questions and also give a valuable insight into the exchange of raw materials and/or finished products between sites. The paper also discloses how a combined analytical methodology represents a positive step in answering the one question which remains unsolved concerning the entire ceramic production in the Vesuvian area: the provenance of the clayey raw materials used. Indeed, the massive pottery production in the Bay of Naples down the ages contrasts with the unavailability of the necessary clayey local resources. © the Partner Organisations 2014.

Giannossa L.C.,University of Bari | Loperfido S.,University of Bari | Caggese M.,University of Bari | De Benedetto G.E.,University of Salento | And 6 more authors.
New Journal of Chemistry | Year: 2013

Fibulae from the archaeological site of Egnatia were examined with the aim of identifying types of alloys, the processes employed for their manufacturing, and outlining the corrosion products. The results obtained, by identifying the raw materials and the technological solutions used allowed us to provide convincing answers to most of the archaeological questions and confirmed the integration of Egnatia in a complex commercial network. In addition, investigations focused on the study of corrosion products, with a view to the planning of more suitable restoration and preservation strategies. © 2013 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.

Saturni L.,Centro Interdipartimentale | Ferretti G.,Centro Interdipartimentale | Ferretti G.,Marche Polytechnic University | Bacchetti T.,Centro Interdipartimentale | Bacchetti T.,Marche Polytechnic University
Nutrients | Year: 2010

The prevalence of Celiac Disease (CD), an autoimmune enteropathy, characterized by chronic inflammation of the intestinal mucosa, atrophy of intestinal villi and several clinical manifestations has increased in recent years. Subjects affected by CD cannot tolerate gluten protein, a mixture of storage proteins contained in several cereals (wheat, rye, barley and derivatives). Gluten free-diet remains the cornerstone treatment for celiac patients. Therefore the absence of gluten in natural and processed foods represents a key aspect of food safety of the gluten-free diet. A promising area is the use of minor or pseudo-cereals such as amaranth, buckwheat, quinoa, sorghum and teff. The paper is focused on the new definition of gluten-free products in food label, the nutritional properties of the gluten-free cereals and their use to prevent nutritional deficiencies of celiac subjects. © 2010 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland.

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