4,967 research outputs found
Motivi letterari nei libri per l’infanzia di Paolo Di Paolo
No full textThe article, organised in the form of a discussion, aims to analyse the themes and motifs of Paolo Di Paolo’s works that are addressed to young audiences. The author has recently published a large number of volumes directed just at younger readers. When beholding the titles that constitute the author’s bibliography, the reader is struck by Di Paolo’s predisposition to transform literary classics: as much in Giacomo il signor bambino as in the edition of the Divina Commedia, the author’s goal is to try to reach his new readers. Therefore, Di Paolo proves to be a prolific author of the genre; in fact, in his bibliography, volumes of fairy tales with a classic slant, such as La mucca volante, are listed as well.L’articolo contiene un’analisi di temi e di motivi delle opere di Paolo Di Paolo dirette al pubblico più piccolo. L’autore negli ultimi anni ha pubblicato un cospicuo numero di volumi indirizzati, infatti, proprio ai lettori più giovani. Ciò che stupisce scorgendo i titoli che costituiscono la bibliografia dell’autore, è la predisposizione a trasformare i classici della letteratura: tanto in Giacomo il signor bambino quanto nell’edizione della Divina Commedia l’obiettivo è cercare di raggiungere i lettori più giovani. Di Paolo si dimostra, quindi, un autore prolifico del genere, tant’è che nell’elenco non mancano volumi fiabeschi dal taglio classico come La mucca volante. Analizzare le opere giovanili dello scrittore costituisce un fatto inedito
Il 'breve' dei sarti di Figline del 1234
No full textRiedizione critica di due precedenti edizioni di un 'breve' della corporazione dei sarti di un centro minore della Toscana medieval
Genealogie del Neoclassicismo: note sul cosiddetto Album Sarti
No full textAnalisi di un album di disegni dell'inizio ottocento conservati presso l'Accademia di S.Luca e abitualmente attribuiti ad Antonio Sarti. L'autore con argomentazioni convincenti ne attribuisce invece almeno in parte la paternità a Raffaele Stern, li cataloga ed analizza criticament
La sapienza ispirata dalla religione : pitture nella Sala degli Esperimenti nel Collegio delle Scuole Pie Fiorentine.
No full text"Pubblicata per la solenne apertura di detta sala Accademica in occasione de' pubblici Esperimenti, dati dagli Scolari delle Scuole Pie di Firenze dal di 3 Settembre 1838 al di 12 dello stesso mese."--Colophon.Text signed: Paolo Sarti [p. 6] and P. Tanzini [p. 16].Mode of access: Internet
Adolfo Sarti e le crisi della Repubblica. Dal dopoguerra all’«autunno caldo» (1945-1969)
No full textPersonalità di rilievo della Democrazia cristiana e uomo delle istituzioni (al governo dal 1966 al 1981), Adolfo Sarti ha prodotto più di trenta annate di diari – una preziosa e ricchissima fonte d’archivio rimasta sinora inedita che racconta in modo dettagliato ed interno le vicende del partito di maggioranza e la storia dell’Italia repubblicana. Questo volume – focalizzato sugli anni che vanno dal secondo dopoguerra alla strage di Piazza Fontana e all’esplosione del cosiddetto «autunno caldo» – costituisce la prima parte di un lavoro storiografico dedicato a Sarti ed analizza gli snodi fondamentali della storia nazionale ricostruendoli a partire dal peculiare punto di vista del politico cuneese, caratterizzato da un insistente richiamo alla categoria della crisi. Per lunghi tratti della sua carriera politica, la democrazia repubblicana gli appare, infatti, fragile e costantemente orientata verso ipotesi di trapassi di regime – declinati variamente nei termini di una seconda Repubblica, una Repubblica presidenziale, un colpo di Stato. Una visione non di rado drammatica che appare in diverse circostanze largamente condivisa da una parte significativa della classe dirigente nazionale
ATP-induced spectral changes in cytochrome c oxidase. A kinetic investigation.
No full textMixing ATP with soluble oxidized cytochrome c oxidase induces a spectral perturbation in the Soret region of the enzyme. This spectral perturbation is observed at ATP concentrations similar to those found to modulate the catalytic activity of cytochrome c oxidase [Malatesta, Antonini, Sarti & Brunori (1987) Biochem. J. 248, 161-165]. The process is reversible and corresponds to a simple binding with Kd = 0.2 mM at 25 degrees C. The absorbance change follows a first-order time course, and analysis of the ATP-concentration-dependence indicates the presence of a rate-limiting monomolecular step that governs the process. From the temperature-dependence of this process, studied at saturating concentrations of ATP, an activation energy of 44 kJ/mol (10.6 kcal/mol) was measured. The spectral perturbation also occurs when cytochrome c oxidase is reconstituted into artificial phospholipid vesicles, with equilibria and kinetics similar to those observed with the soluble enzyme. Mixing ATP with soluble oxidized cyanide-bound cytochrome c oxidase induces a different spectral perturbation, and the apparent affinity of ATP for the enzyme is substantially increased. There is no absolute specificity for ATP, because EGTA, inositol hexakisphosphate, sulphate and phosphate are all able to induce an identical spectral perturbation with the same kinetics, although the value of the apparent Kd is different for the various anions. The presence of Mg2+ ions decreases, in a saturation-dependent fashion, the apparent affinity of cytochrome c oxidase for ATP. The absorbance change can be correlated to the displacement of the Ca2+ bound to cytochrome c oxidase
CONTROL OF CYTOCHROME-OXIDASE ACTIVITY - A TRANSIENT SPECTROSCOPY STUDY
No full textThe kinetics of cytochrome oxidase reconstituted into small phospholipid vesicles (COV) has been followed by transient optical spectroscopy under steady-state and pre-steady-state conditions, in the presence and absence of ionophores. The effect of valinomycin on the activity of reconstituted cytochrome oxidase is shown to depend on the absolute concentration of the ionophore and on the number of turnovers elapsed by the enzyme; this novel observation, which escaped previous investigations, may account for important differences in results and therefore in interpretation of the mechanism of control of the enzyme activity as between Brunori et al. (Brunori, M., Sarti, P., Colosimo, A., Antonini, G., Malatesta, F., Jones, M. G., and Wilson, M. T. (1985) EMBO J. 4, 2365-2368), Gregory and Ferguson-Miller (Gregory, L., and Ferguson-Miller, S. (1989) Biochemistry 28, 2655-2662) and Capitanio et al. (Capitanio, N., De Nitto, E., Villani, G., Capitanio, G., and Papa, S. (1990) Biochemistry 29, 2939-2944). Quantitative analysis of the optical spectra acquired within 10 ms over a large wavelength and time range (500-650 nm and 5 ms to 60 s) under different experimental conditions, indicates that the electrical component of the transmembrane electro-chemical gradient controls the rate of the internal electron transfer from cytochrome alpha-Cu(A) to cytochrome alpa-3-Cu(B) as well as the cytochrome c to cytochrome alpha-electron transfer. The slow down of cytochrome oxidase activity observed in the presence of valinomycin after several (> 10) turnovers is attributed to alkalinization of the vesicle interior, which affects the internal electron transfer rate. These two mechanisms of control act most likely independently
Lumachella astracane di S. Paolo
No full textLumachella appartenente alla collezione delle pietre ornamentali “Sarti” impiegate nell’edilizia del Mondo Antico e del Rinascimento fino al 1876, anno della donazione alla Collezione di Mineralogia “Museo Luigi Bombicci” dell’Università di Bologna da parte dell’architetto Antonio Sarti
CONTROL OF ELECTRON-TRANSFER BY THE ELECTROCHEMICAL POTENTIAL GRADIENT IN CYTOCHROME-C OXIDASE RECONSTITUTED INTO PHOSPHOLIPID-VESICLES
No full textThe kinetics of electron transfer between cytochrome-c oxidase and ruthenium hexamine has been characterized using the native enzyme or its cyanide complex either solubilized by detergent (soluble cytochrome oxidase) or reconstituted into artificial phospholipid vesicles (cytochrome oxidase-containing vesicles). Ru(NH3)2+6 (Ru(II] reduces oxidized cytochrome a, following (by-and-large) bimolecular kinetics; the second order rate constant using the cyanide complex of the enzyme is 1.5 x 10(6) M-1 s-1, for the enzyme in detergent, and slightly higher for COV. In the case of COV the kinetics are not affected by the addition of ionophores. Upon mixing fully reduced cytochrome oxidase with oxygen (in the presence of excess reductants), the oxidation leading to the pulsed enzyme is followed by a steady state phase and (eventually) by complete re-reduction. When the concentrations of dioxygen and oxidase are sufficiently low (micromolar range), the time course of oxidation can be resolved by stopped flow at room temperature, yielding an apparent bimolecular rate constant of 5 x 10(7) M-1 s-1. After exhaustion of oxygen and end of steady state, re-reduction of the pulsed enzyme by the excess Ru(II) is observed; the concentration dependence shows that the rate of re-reduction is limited at 3 s-1 in detergent; this limiting value is assigned to the intramolecular electron transfer process from cytochrome a-Cua to the binuclear center. Using the reconstituted enzyme, the internal electron transfer step is sensitive to ionophores, increasing from 2-3 to 7-8 s-1 upon addition of valinomycin and carbonyl cyanide m-chlorophenylhydrazone. This finding indicates for the first time an effect of the electrochemical potential across the membrane on the internal electron transfer rate; the results are compared with expectations based on the hypothesis formulated by Brunori et al. (Brunori, M., Sarti, P., Colosimo, A., Antonini, G., Malatesta, F., Jones, M.G., and Wilson, M.T. (1985) EMBO J. 4, 2365-2368), and their bioenergetic relevance is discussed with reference to the proton pumping activity of the enzyme
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