1,784 research outputs found
Comprendere le immagini: segni iconici e segni plastici
No full textQuesto scritto corrisponde al primo dei tre capitoli di cui sono autrice all’interno del volume. Si tratta del capitolo quinto, intitolato "Comprendere le immagini: segni iconici e segni plastici". Avvalendosi dei contributi teorici e metodologici offerti da svariate discipline (l’iconologia, la semiotica e la retorica visiva), esso affronta la complessa questione delle modalità attraverso le quali riconosciamo e comprendiamo le immagini, siano esse le immagini artistiche o quelle presenti nei manifesti pubblicitari. In particolare, vengono indagati i seguenti problemi: il rapporto tra visuale e verbale; il rapporto tra immagini e oggetti del mondo; l’esistenza di una “grammatica” dell’immagine, con le sue peculiari relazioni tra il piano dell’espressione e il piano del contenuto, così come tra segni iconici e segni plastici; i processi di significazione dell’immagine, fra denotazione e connotazione
Henri Temianka Correspondence; (contini)
No full textThis collection contains material pertaining to the life, career, and activities of Henri Temianka, violin virtuoso, conductor, music teacher, and author. Materials include correspondence, concert programs and flyers, music scores, photographs, and books.https://digitalcommons.chapman.edu/temianka_correspondence/1640/thumbnail.jp
Improving the reliability of MM-PBSA and MM-GBSA binding energy predictions by explicitly considering ligand solvation shells
No full textMolecular Mechanics Poisson-Boltzmann Surface Area (MM-PBSA) and Molecular Mechanics Generalized Born Surface Area (MM-GBSA) are interesting techniques for drug design/discovery applications, but sometimes the correlation between predicted and experimental binding energies might result unsatisfactory.
Nowadays, a certain effort is focused on ameliorating the solvation term in MM-PB/GBSA calculations and some strategies were applied to obtain a better correlation between calculations and experiments.
Some authors reported that the predictivity of MM-PB/GBSA calculations might be improved by modulating the internal dielectric constant (εin).1 Unfortunately, a universal εin, suitable for all systems was not found and a thorough analysis of the binding pocket is needed to choose the proper value of εin.
MM-PB/GBSA binding energy predictions might also be improved by explicitly considering selected water molecules in the calculation, however this strategy is controversial.2-5
Herein, we report on how the explicit inclusion of variably populated ligand hydration shells might improve the correlation between MM-PB/GBSA computed binding energy and experimental activities.
DNA-topoisomerase, α-thrombin, penicillopepsin, avidin, and neuraminidase complexes with different ligands were considered as test sets, and ligand hydration shells populated by an increasing number of water molecules were systematically evaluated.
We found that the consideration of a hydration shell populated by a number of water residues (Nwat) between 30 and 70 provided in all the considered examples a positive effect on correlation between MM-PB/GBSA calculated binding affinities and experimental activities, with a negligible increment of computational cost.6
REFERENCES
1. Hou, T.; Wang, J.; Li, Y.; Wang, W., J. Chem. Inf. Model. 2011, 51, 69-82.
2. Wong, S.; Amaro, R. E.; McCammon, J. A., J. Chem. Theory Comput. 2009, 5, 422-429.
3. Hayes, J. M.; Skamnaki, V. T.; Archontis, G.; Lamprakis, C.; Sarrou, J.; Bischler, N.; Skaltsounis, A.-L.; Zographos, S. E.; Oikonomakos, N. G., Proteins 2011, 79, 703-19.
4. Freedman, H.; Huynh, L. P.; Le, L.; Cheatham, I. I. I. T. E.; Tuszynski, J. A.; Truong, T. N., J. Phys. Chem. B 2010, 114, 2227-2237.
5. Checa, A.; Ortiz, A. R.; de Pascual-Teresa, B.; Gago, F., J. Med. Chem. 1997, 40 (25), 4136-45.
6. Maffucci, I.; Contini, A., J. Chem. Theory Comput. 2013, 9 (6), 2706-2717
Tautomeric equilibria of benzopyranoimidazoles: useful insights from quantum chemical calculation and NMR
No full textThe development of novel syntetic strategies for achieving compounds containing the coumarin nucleus condensed to several heterocycles has been the subject of our research for the latter few years. [1] Such heterocycles are pharmacologically relevant as CNS depressants, [2] growth inhibitors of mammalian cancer [3] and also phosphodiesterase VII inhibitors for treatment of immunity-associated diseases. [4]
Recently we reported the synthesis of some substituted benzopyranoimidazolones, and we pointed out the possibility of such heterocycles to exist in solution in at least two tautomeric forms, the N3-H and the N1-H tautomers (Fig. 1). [5] The study and quantitative evaluation of prototropic tautomerism in heterocyclic compounds is of primary interest, influencing both reactivity and biological behavior, for example the ability of a drug to bind the active site of a target enzyme [6]. Unfortunately literature does not report any reliable structural information and neither experimental data concerning tautomerism on pyranoimidazolone nucleus. Furthermore RT NMR experiments conducted by us so far were able to evidence the presence of at least two tautomers only for compound 4d and the attempts previously reported by us to unequivocally assign the preferred tautomeric structure by NMR were unsuccessful. The only result was obtained by N-methylation of compound 4d, were just the N3-CH3 product was isolated both at high and low reaction temperatures. However the reaction condition adopted could have influenced the tautomeric equilibrium. On the other hand tautomerism has been successfully described on various substituted imidazoles by ab-initio and DFT calculations in both gas-phase and solution within the continuum solvent model or evaluating explicit solvent interactions. [7]
In our previous work, where the main object was the development of a synthetic strategy for benzopiranoimidazoles, preliminary quantum chemical calculations explained only in part the tautomeric behavior observed, thus the need of a throughout theoretical and experimental investigation. The relative stability of all the possible tautomers for [1]benzopyrano[3,4-d]imidazol-4(3H)-ones, namely the N3-H (alpha tautomer), N1-H (beta tautomer), coumarin O-H (gamma tautomer) and C2-H (delta tautomer), has been evaluated by mean of HF and B3LYP calculations, including the solvent contribution by the SCRF PCM model. Furthermore the 13C and 1H chemical shifts were calculated by GIAO technique at the HF/6-311+G(2d,p) and B3LYP/TZVP levels of theory both in gas phase and in solution by using the PCM model for DMSO. The calculation of 13C chemical shifts by GIAO technique and the comparison with the experimental has been reported as one of the most reliable methods for the investigation of tautomeric equilibria in solution [8]. Finally, 1H NMR spectra were recorded in CD3COCD3 at 500 Mhz at variable temperature in a range from RT to –60°C in order to evidence the presence of the most probable tautomers by progressively lowering their interconversion rates.
The combination of the above mentioned theoretical techniques and experimental NMR allowed us to demonstrate that:
1.The only relevant tautomeric equilibrium for benzopyranoimidazolones is between alpha and beta forms.
2.All compounds 4a-e are able to exhibit tautomeric equilibrium in polar solvents.
3.The interconversion rate between alpha and beta tautomers is fast, thus by NMR is possibile to detect the presence of both tautomers only at low temperatures, otherwise averaged signals are recorded.
Bibliography
1.[a] E.M. Beccalli, A. Contini and P. Trimarco, Eur. J. Org. Chem., 2003, 3976-3984, [b] E.M. Beccalli, A. Contini and P. Trimarco, Tetrahedron Letters, 2004, 45, 3447-3449.
2.V. L. Savel’ev, N. T. Pryanishnikova, V. A. Zagorevskii, I. V. Chernyakova, O.S. Artamonova, V. V. Shavyrina, L. I. Malysheva, Khim. Farm. Zh. 1983, 17, 697-700; see Chem. Abstr. 1983, 99, 158325.
3.M. Trkovnik, V. Kalaj, D. Kitan, Org. Prep. Proced. Int., 1987, 19, 450-455
4.M. Eggenweiler, J. Rochus, M. Wolf, M. Gassen, O. Poeschke, Merck Patent Gmbh, Germany, PCT Int. Appl. 2001; see Chem. Abstr. 2001, 134, 331619.
5.See ref 1a
6.P. Pospisil, P. Ballmer, G. Folkers, L. Scapozza, Tautomerism of nucleobase derivatives and their score in virtual screening to thymidine kinase, Abstracts of Papers, 224th ACS National Meeting, Boston, MA, United States, August 18-22, 2002
7.[a] O. V. Shishkin, O. S. Sukhanov, L. Gorb and J. Leszczynski, PCCP, 2002, 4, 5359-5364. [b] G. -S. Li, M. F. Ruiz-Lopez, M. S. Zhang, B. Maigret, J. Mol. Struct. (Theochem), 1998, 422, 197-204. [c] E. D. Raczyńska, Anal. Chim. Acta, 1997, 348, 431-441. [d] G. A. Worth, P. M. King, W. G. Richards, Biochem. Biophys. Acta, 1989, 993, 134-136. [e] G. -S. Li, M. F. Ruiz-Lopez, M. -S. Zhang, B. Maigret, J. Phys. Chem., 1997, 101, 7885-7892. [f] F. J. Luque, J. M. Lopez-Bes, J. Cemeli, M. Aroztegui, M. Orozco, Theor. Chem. Acc., 1997, 96, 105-113.
8.[a] N. E. Campillo, C. Montero, J. A. Páez, J. Mol. Struct. (Theochem), 2004, 678, 83-89. [b] E. Kleinpeter and A. Koch, J. Phys. Org. Chem., 2001, 14, 566-576
Un articolo perduto e una lettera ritrovata. Carteggio Contini-Cecchi-Raimondi
No full textWhen Giuseppe Raimondi’s novel Giuseppe in Italia was published by Mondadori, in April 1949,
the author and his friends Gianfranco Contini and Emilio Cecchi began a period of intense correspondence.
Such correspondence, as presented herein, from May to August 1949, is evidence
of the deep friendship that existed in the relations between the three protagonists of Italian
literary culture and documents a “disagreement” between the great philologist and the author
of Pesci rossi which, in the light of some new letters, confirms again the rigour and ethical-moral
strictness which Contini always stood by, as much in his work as in his life
GIANFRANCO CONTINI ALFREDO SCHIAFFINI CARTEGGIO (1935-1971)
No full textFra tutti i carteggi di Gianfranco Contini (e ne sono stati pubblicati ormai molti: con Carlo Emilio Gadda, Eugenio Montale, Emilio Cecchi, Aldo Capitini, Luigi Russo, Giorgio Pasquali, Giuseppe De Luca, ecc.), quello con Alfredo Schiaffini ha un posto particolare: è il più considerevole per numero di lettere e per durata cronologica (dal 1935 al 1971) con un “addetto ai lavori”, un collega. Quando Contini scrive a Schiaffini per la prima volta, ha ventitré anni. Si è appena laureato in Filologia Romanza all'Università di Pavia, e ha vinto una borsa di studio per perfezionarsi a Parigi, con Joseph Bédier. Schiaffini, quando riceve quella prima lettera da Parigi, il 18 febbraio 1935, ha quarant'anni. È un professore affermato, con cattedra a Genova e incarichi alla Scuola Normale di Pisa. La complicità è immediata. L'affetto, durerà per tutta la vita, e i contatti non si interromperanno mai, fino alla morte di Schiaffini, avvenuta nel 1971.
Succede, nel frattempo, di tutto. Contini diventa la star indiscussa della filologia italiana, venerato e temuto da amici e colleghi, autore di saggi mirabili, che rivoluzionano la disciplina, e punto di riferimento per molti scrittori contemporanei (Montale, Gadda e Pasolini sono solo i più celebri). Nasce, in polemica con Benedetto Croce, e su impulso proprio di Contini, la “critica delle varianti”, che Schiaffini (è tra gli aspetti poco noti emersi da questo carteggio) è fra i primi ad appoggiare e sostenere.
Nel 1935, c'è la guerra. Le biblioteche universitarie non comprano riviste straniere, e Contini procura a Schiaffini, da Parigi, estratti introvabili in Italia, acquistati da Droz. Entrambi i corrispondenti perdono, negli anni della guerra, libri, carte, lettere.
La ricostruzione li vede ancora l'uno accanto all'altro, impegnati, con ruoli diversi, nel programma di ricostruzione della storia letteraria nazionale portato avanti dalla casa editrice Riccardo Ricciardi: Schiaffini è coinvolto da Mattioli fin dal 1949 nella direzione della collana “La letteratura italiana. Storia e testi”, insieme a Pietro Pancrazi, che intende stabilire un 'canone' della letteratura italiana in 75 volumi, da consegnare alla classe dirigente del futuro. Prima ancora che l'incarico sia ufficializzato, ne dà notizia a Contini, e gli affida l'incarico di curare per la collana i due volumi dei Poeti del Duecento, che usciranno nel 1961, e cambieranno il modo di pubblicare i testi delle origini. Poco più tardi, Schiaffini promuove alla Ricciardi una nuova casa editrice, i “Documenti di filologia”: che dirigerà scegliendo di avere al suo fianco, ancora una volta, Contini.
Quarant'anni di storia non solo accademica italiana, come si riflettono nelle lettere di due studiosi che hanno messo le basi della disciplina filologica in Italia.The exchange of letters between Gianfranco Contini and Alfredo Schiaffini is quite peculiar, even if compared with the many ones Contini had with Carlo Emilio Gadda, Eugenio Montale, Emilio Cecchi, Aldo Capitini, Luigi Russo, Giorgio Pasquali, Giuseppe De Luca and others, already published. It is the most considerable for its length and for the incredible number of letters: it lasts from 1935 to 1971 and involves two “colleagues”. Contini addresses his first letter to Schiaffinin on February 18th, 1935: he is only 23 y.o., he has just taken his degree in Romance Philology and obtained a scholarship to specialize with Joseph Bedier in Paris. Schiaffini is a 40 y. o. well known professor at Genova University, who lectures at Pisa Scuola Normale Superiore. Their complicity is immediate; they love each other and won’t interrupt their friendly relation up to Schiaffini’s death in 1971.
Contini is soon going to become the undisputed ‘star’ of Italian Philology, revered and feared by friends and colleagues, author of admirable essays which turn his teaching upside down; the reference point of many contemporary writers (Montale, Gadda and Pasolini are only the best known). Schiaffini supports and backs up at once “critica delle varianti”, born under the impulse of Contini and in dispute with Benedetto Croce: this is one of the less known aspects these letters have drawn the attention on.
In 1935 war is on. University libraries don’t buy foreign reviews and Contini sends Schiaffini otherwise unobtainable off prints he buys at Droz. During the war both Contini and Schiaffini lose books, papers and letters.
Reconstruction sees them again side by side, engaged with different roles in a programme of rebuilding the national literary history planned by Riccardo Ricciardi. Since 1949 Schiaffini has been called by Mattioli, together with Piero Pancrazi, in the executive staff of “La letteratura italiana”. The aim is to establish a “canon” of the Italian Literature in 75 volumes for the ruling class of the future. Schiaffini writes about his new job to his dear friend Contini – even before its officialization, and gives him the task to edit the two volumes on Poeti del Duecento. These will be ready in 1961 and will change the way of publishing the texts of the origins of our lietrature. Soon after Schiaffini promotes “Documenti di filologia”: once again Contini is at his side to share the management.
Forty years of Italian History – not only from an academic point of view, are reflected in the letters of two scholars who laid the foundations of the philological discipline in Italy
Performing the undiscovered solo piano works of Italian composer Lucia Contini Anselmi (1876-1913)
No full text© 2022 Quilby NelsonLucia Contini Anselmi (b.1876-d.? after 1913) was an Italian composer and pianist. Born in Vercelli, Italy, Contini Anselmi wrote over thirty works, mainly for solo piano. Despite the current surge of research into women composers of the nineteenth and twentieth centuries, there is little known about Contini Anselmi with no major research to date, compounded by the lack of research into Italian female composers of this time period. Therefore, this study will serve to fill both these gaps in the literature. The goal of this research is to present a performance approach to two of Contini Anselmi’s works, Ludentia Op. 11 (1913) and Sibylla Cumaea Op. 15 (1916) through a practice-led research orientation. This will be realised through the application of the writings in Contini Anselmi’s treatise, Della tecnica per l’esecuzione della musica sul pianoforte e sua interpretazione, a previously unknown document published in 1908
Munari, Rodari e Malaguzzi nell’educazione alla creatività
No full textIl capitolo si inserisce in un volume che si propone un duplice obiettivo: 1) individuare i modelli teorici che stanno alla base dell’odierno concetto di creatività; 2) individuare pratiche, metodologie e strategie educative che consentano di promuovere la creatività nei bambini di età prescolare. Il capitolo in questione si rapporta a entrambi gli obiettivi: esso ricostruisce infatti alcuni nodi essenziali delle concezioni della creatività elaborate da Bruno Munari (1907-1998), Gianni Rodari (1920-1980) e Loris Malaguzzi (1920-1994), con particolare riguardo alle idee o alle proposte che hanno avuto più influenza su educatori e istituzioni educative, insegnanti e scuole, e che sembrano tuttora estremamente attuali, in grado di orientare l’esplorazione di nuove strategie di educazione alla creatività.
Il capitolo è stato unitariamente pensato e discusso dalle autrici. Tuttavia, per quanto concerne la stesura del testo, Annamaria Contini ha redatto i paragrafi 4.1, 4.1.1, 4.1.2, 4.1.3, 4. 2, 4.2.1 e 4.2.2, mentre Chiara Bertolini ha redatto i paragrafi 4.2.3, 4.3 e 4.4
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