112,707 research outputs found
Phantazontes. Visioni dell’arte bizantina
No full textl titolo di questa monografia collettiva, “Phantazontes”, si spiega con la traduzione del termine greco “phantasia”, che significa immaginazione visiva. Attraverso approcci metodologici diversi, ma complementari, gli autori dei quattro saggi affrontano il problema delle “visioni” dell’arte bizantina, proponendo altrettanti percorsi conoscitivi incentrati sui temi dell’immagine, della tradizione testuale, dei condizionamenti storici e storiografici, nonché sui processi cognitivi che sono alla base della percezione e della ricezione bizantina tra antichità e modernità
Letteratura cinese contemporanea. Correnti, autori e testi dal 1949 a oggi
No full textUn quadro completo della letteratura cinese degli ultimi sessant'anni attraverso una selezione di testi prodotti dagli autori cinesi più noti e affermati, sia in ambito nazionale che internazionale. L'antologia è divisa in sette capitoli. Ogni capitolo è corredato di un'introduzione al contesto storico e culturale, una selezione di testi letterari (narrativa, poesia, teatro), testimonianze e saggi di critica in traduzione letteraria, schede biografiche deglia utori, domande di verifica e ripasso, bibliografia ragionata
Extension of the AMBER force field to cyclic a,a dialkylated peptides
No full textThe popular biomolecular AMBER (ff99SB) force field (FF) has been extended with new
parameters for the simulations of peptides containing a,a dialkylated residues with cyclic side
chains. Together with the recent set of nitroxide parameters [E. Stendardo, A. Pedone, P. Cimino,
M. C. Menziani, O. Crescenzi and V. Barone, Phys. Chem. Chem. Phys., 2010, 12, 11697] this
extension allows treating the TOAC residue (TOAC, 2,2,6,6-tetramethylpiperidine-1-oxyl-4-
amino-4-carboxylic acid) widely used as a spin label in protein studies. All the conformational
minima of the Ac–Ac6C–NMe (Ac = acetyl, Ac6C = 1-aminocyclohexaneacetic acid, NMe =
methylamino) and Ac–TOAC–NMe dipeptides have been examined in terms of geometry and
relative energy stability by Quantum Mechanical (QM) computations employing an hybrid
density functional (PBE0) for an extended training set of conformers with various folds. A very
good agreement between QM and MM (molecular mechanics) data has been obtained in most of
the investigated properties, including solvent effects. Finally, the new set of parameters has been
validated by comparing the conformational and dynamical behavior of TOAC-labeled
polypeptides investigated by means of classical molecular dynamics (MD) simulations with QM
data and experimental evidence. The new FF accurately describes the tuning of conformational
and dynamical behavior of the Ac–TOAC–NMe dipeptide and double spin-labeled heptapeptide
Fmoc–(Aib–Aib–TOAC)2–Aib–OMe (Fmoc, fluorenyl-9-methoxycarbonyl; Aib,
a-aminoisobutyric acid; OMe, methoxy) by solvents with different polarity. In particular, we found
that the 310 helical structure of heptapeptide is the most stable one in vacuo, with a geometry very
similar to the X-ray crystallographic structure, whereas a conformational equilibrium between the
310- and a-helical structures is established in aqueous solution, in agreement with EPR data
Apud Acta. Studi sul processo romano alla luce della documentazione papirologica (IV-VI sec. D.C.)
No full textQuesta breve opera in formato elettronico presenta alcuni risultati preliminari di un’indagine sul tardo processo romano, analizzato dalla peculiare prospettiva dei verbali processuali greco-latini su papiro. Il volume contiene la riedizione commentata di tre documenti. Il primo, P.Mich. inv. 4014 (ChLA V 292), risale al IV sec. d.C. e si riferisce all’elezione del praepositus pagi da parte dei curiales. Del secondo, P.Mich. VII 463 (ChLA V 293), l’a. propone una datazione alla metà del V sec. d.C. sulla base di un passo di Teofilo contenenti alcuni riferimenti all’onomastica dei governatori provinciali. Il terzo, P.Berol. inv. 2745 (SB I 5357 = ChLAX 407), è un testo più noto alla romanistica, poiché Collinet ritenne di inquadrarvi un esempio di procedura per rescritto risalente alla seconda metà del V sec. d.C.; confutando l’opinione del romanista francese, la nuova edizione commentata dell’a. ricollega il reperto al processo civile della prima età giustinianea. Lo studio si inserisce nel contesto del progetto ERC Platinum (P.I. Prof.ssa Maria Chiara Scappaticcio)
Unraveling Solvent Effects on the Electronic Absorption Spectra of TRITC Fluorophore in Solution: a Theoretical TD-DFT/PCM study
No full textIn this paper the equilibrium between the two ground state forms of TRITC in solvents ofdifferent polarity has been studied by means of state of the art DFT calculations using thepolarizable continuum model (PCM) for including bulk solvent effects. TD-DFT/PCMcalculations have been used to calculate vertical excitation energies and the UV-Vis spectra ofTRITC has been interpreted in terms of the equilibrium between different forms, which ismodulated by the microenvironment embedding the molecule. We show that the most intenseabsorption bands are sensitive to solute–solvent interactions and provide a distinctive signature ofspecific interactions. The good agreement with experimental data makes our approach suitable tostudy and monitor modifications of the chemical environment of fluorophores in differentsolutions as well as in interaction with biological systems and nanoparticles
An integrated computational protocol for the accurate prediction of EPR and PNMR parameters of aminoxyl radicals in solution
No full textMagnetic spectroscopic techniques such as electron paramagnetic resonance (EPR) and paramagneticNMR(PNMR) are valuabletools for understanding the structure and dynamics of complex systems such as, for example, biomolecules or nanomaterialslabeled with suitable free radicals. Unfortunately, such spectra do not give direct access to the radical structure because of thesubtle interplay between several different effects not easily separable and evaluable by experimentalists alone. In this respect,computational spectroscopy is becoming an essential and versatile tool for the assignment and interpretation of experimentalspectra. In this article, the new integrated computational approaches developed in the recent years in our research groupare reviewed. Such approaches have been applied to two widely used spin probes showing that proper account of stereoelectronic,environmental and dynamical effects leads to magnetic properties in remarkable agreement with experimentalresults
The Pseudo-Kufic Ornament and the Problem of Cross-Cultural Relationships Between Byzantium and Islam
No full textThe aim of the paper is to analyze pseudo-kufic ornament in Byzantine art and the reception of the topic in Byzantine Studies. The pseudo-kufic ornamental motifs seem to occupy a middle position between the purely formal abstractness and freedom of arabesque and the purely symbolic form of a semantic and referential mean, borrowed from an alien language, moreover. This double nature (that is also a double negation) makes of pseudo-kufic decoration a very interesting liminal object, an object of “transition”, as it were, at the crossroad of different domains. Starting from an assessment of the theoretical questions raised by the aesthetic peculiarities of this kind of ornament, we consider, from this specific point of view, the problem of the cross-cultural impact of Islamic and islamicizing formal repertory on Byzantine ornament, focusing in particular on a hitherto unpublished illuminated manuscript dated to the tenth century and held by the Marciana Library in Venic
Interplay of stereo-electronic, environmental, and dynamical effects in determining the EPR parameters of aromatic spin-probes: INDCO as a test case.
No full textAn integrated computational strategy for the evaluation of reliable structures and magneticproperties of spin probes and spin labels has been extended to aromatic species. From anelectronic point of view, delocalization of the unpaired electron density over aromatic moietiesreduces significantly the computed nitrogen isotropic hyperfine coupling constant (AN) withrespect to values characteristic of aliphatic nitroxides. Solvent effects in not too high polaritymedia are quite small, but not negligible. At this stage computed AN are lower than theirexperimental counterparts by more than 1 G. Inclusion of vibrational averaging effects bymolecular dynamics simulations with a new reliable force field restores full agreement withexperiment pointing out the limits of static approaches irrespective of the sophistication of theelectronic quantum mechanical method. The generality and computational effectiveness of theproposed integrated approach paves the route toward a reliable analysis of the interplay ofstereo-electronic, environmental, and dynamical effects in tuning the properties of large flexiblemagnetic systems of biological and technological interest
Chinese Entrepreneurs in Italy. An Asymmetric Socio-Economic Embeddedness
No full textThis paper aims at reconceptualizing the role of Chinese immigrant entrepreneuship in Italian economy and society, using an approach grounded in the embeddedness perspective as portrayed by Granovetter and other scholars in New Economic Sociology.
In this respect, ethnic specialisations found in Italian local production systems are seen as part of a more general system of inter-group relations in the global economic restructuring.
In orther to disentangle the relationship between two forms of ethnoindustrialisation (Italian industrial districts and clusters of Chinese SMEs), we will map Chinese settlement and entrepreneurial patterns – showing the centrality of local economies – and we will identify interactions between immigration paths and local communities. The evidence of unequal participation and exploitation will be placed in the context of a critical restructuring of Italian economy, that will likely mean also the need for a radical transformation of Chinese economic participation in Italy
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