1,721,030 research outputs found
Umanisti e cultura classica nella Sardegna del '500: 3.: L'inventario dei beni e dei libri di Monserrat Rosselló
Full text linkNel 1987, nel corso di una visita all'Archivio di Stato di Cagliari alla ricerca di documenti inediti su Giovanni Francesco Fara, avemmo modo di prendere visione del ricchissimo inventario (dei beni e librario) di Monserrat Rosselló e di ottenerne poco tempo dopo una copia fotografica. Prendeva allora corpo il progetto, che ormai si avvia a compimento, di pubblicare tutti i principali inventari librari della Sardegna del XVI secolo, in particolare quelli di Fontana, Fara, Canyelles, Parragues e Rosselló, al fine di indagare su due problematiche principali, quella della circolazione libraria e della diffusione della cultura classica nell'isola. Con l'opera che ora presentiamo, a cura di chi scrive e di Maria Teresa Laneri che ha preparato l'edizione critica dell'inventario, si chiude il ciclo iniziato con la pubblicazione del volume di Fara e Fontana (Sassari 1988), di Canyelles (Sassari 1989) e di Parragues (Sassari 1993), nella speranza che la nostra fatica possa risultare utile a chiarire i rapporti complessi che corrono tra la cultura europea del XVI secolo e quella della nostra isola. Sino a non molto tempo fa si credeva che l'isolamento - geografico e culturale - del quale la Sardegna soffriva e l'assenza di strutture sociali e civili al livello delle altre regioni del vecchio continente avessero creato una sorta di barriera alla circolazione delle idee e della cultura, il che è forse stato delineato meglio attraverso la pubblicazione di una serie di opere con le quali crediamo di aver offerto il nostro contributo negli ultimi anni
Competitive 1,3-cycloaddition of benzonitrile oxides to carbon-carbon and carbon-nitrogen multiple bonds
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15N and 13C-NMR Study of protonated Monoaminopyridines in CDCl3/DMSO
No full textThe 2-, 3- and 4-amino-pyridine and their protonated forms, obtained by reaction with pyridinium chloride, were
investigated by 15N NMR spectroscopy. Exhaustive evidence has been found that the protonation occurs mainly on
the annular nitrogen. Protonation of 4-aminopyridine by dehydrohalogenation of 1,1,2,2-tetrachloroethane (TCE)
was also studied by 13C NMR spectroscopy, which indicated that the protonation occurs via the formation of
adducts
A kinetic Study of the 1,3-cycloaddition of benzonitrile oxides to parasubstituted Î2-aminocinnamonitriles
No full textStable arylnitrile oxides undergo 1,3-cycloaddition to Î2- aminocinnamonitriles at the Câ¡N or the C=C bond, which gives rise to 3,5-disubstituted 1,2,4-oxadiazoles or 3,5-diaryl-4-cyanoisoxazoles, respectively, by parallel reactions in different solvents. Overall kinetics were measured at temperatures in the range 50-90 °C; product selectivities were determined by HPLC rate coefficients for the parallel reactions were, thus, obtained. Rates were enhanced by increasing the solvent polarity. Hammett plots for substitution on the nitrile oxide benzene ring were V-shaped; those for substitution on the enaminonitrile benzene ring had negative p-values
Biodegradation of polycyclic aromatic hydrocarbons by pleurotus sajor-caju
No full textPolycyclic aromatic hydrocarbons (PAHs) are considered priority pollutants because they have potentially dangerous effects on the environment and human health. Bioremediation has recently become attractive to restore polluted sites, because it is not expensive and fulfils the most important properties required by the current regulations. In this work the capability of a white-rot fungi, Pleurotus sajor-caju, was assessed for degradation of pyrene and chrysene. The main objective was to investigate the effects of pollutant concentration on the mycelium growth and find the conditions that can enhance the microorganism tolerance when exposed to pyrene and chrysene. The tests carried out in Petri dishes showed that chrysene inhibited mycelium growth, whereas pyrene was well tolerated. Experiments in liquid medium evidenced that the mycelium was able to degrade pyrene with a removal efficienty greater than 90%
Pyrene and chrysene tolerance and biodegradation capability of pleurotus sajor-caju
Full text linkIntroduction: The present work focused on the biodegradation capability of a white-rot fungus, the Pleurotus sajor-caju, when exposed to polycyclic aromatic hydrocarbons. Methods: The research was carried out by using in vitro systems developed on Petri dishes, to evaluate the fungal tolerance to pyrene and chrysene, followed by experiments in liquid medium. The first experimental campaign was necessary to evaluate the conditions promoting fungal growth and tolerance (presence of surfactants, peptone, copper sulphate and lecithin) and it was designed and analysed using statistical techniques. Results: It was found that the fungal population growth is strongly inhibited by chrysene presence. On the other hand, pyrene had a mild negative impact on the mycelia growth, which seemed to be positively influenced by the presence of Tween 80 and copper sulphate. Starting from these results, the behaviour of Pleurotus sajor-caju in presence of pyrene was investigated in liquid medium. Results showed that the depletion of pyrene was evident during a period of 20 days, and removal efficiency was greater than 90%
Synthesis of 1,3-Benzodioxoles, 1,3-Benzoxathioles and 1,3-Benzodithioles from Allenic Derivatives
No full textof New Heterocycles through a Cation- Driven Tandem Ring- Enlargement- Annulation reaction
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