88,709 research outputs found
PATRICK MODIANO. UNE IDENTITÉ EN DÉPÔT
No full textLe immagini del panier à salade (la camionetta della polizia utilizzata per le retate degli «indesiderabili») e del dépôt (Drancy, metonimicamente inteso come luogo di prigionia, prima di raggiungere Auschwitz) servono a Modiano per ricostruire il suo legame con la Storia, con le sue origini ebraiche e con il padre. Il furgone inanimato, «oggetto desueto nell’immaginario letterario» (F. ORLANDO), incarna in molti testi dell’autore il «ritorno del represso» (ID.): minacciosamente parcheggiato sul marciapiede ad perpetuam rei memoriam, esso rievoca le violenze degli anni neri, scatenando un’onda d’urto che investe e ossessiona le epoche successive. Questa immagine, continuamente interrogata e riscritta da Modiano, a partire dalla fuga paterna del 1942, si accompagna quasi sempre a quella del dépôt: luogo di coercizione e di dolore, prodromo della morte cui Albert è miracolosamente scampato, Drancy (così come Compiègne o Pithiviers, solo per citare i campi di transito della Francia settentrionale) conserva ancora la memoria di quell’Uomo «indistruttibile» perché «infinitamente distrutto» (M. BLANCHOT). Quel «quasi nulla», relegato ai margini della società, lasciato «in deposito» per poi essere mandato a morte, si fa sedimento che resiste ancora, strenuamente, all’oblio. Sulle figure del panier à salade e del dépôt si riscrivono, allo stesso tempo, il rapporto tra un padre e un figlio, sulle ceneri della Seconda Guerra mondiale, e il segreto di un’estetica letteraria
Lo scarto dalla norma: corpo e corporeità nella letteratura contemporanea
No full textIl terzo numero di «NuBE» offre una panoramica trasversale su universi linguistici e culturali differenti per mostrare come la letteratura, grazie al suo potenziale euristico e visionario, possa guidare la riflessione intorno alla trasformazione della relazione tra l’individuo contemporaneo e il proprio corpo. Esplorare la fenomenologia del corpo nella letteratura contemporanea significa riflettere su ambiti dell’esperienza tanto disparati quanto contigui e complementari. Senza pretesa di esaustività, la presente raccolta di saggi si concentra sul corpo nel suo legame con la costruzione dell’identità, rispetto alla memoria individuale o collettiva; sulle metamorfosi del corpo, ivi compreso anche il suo essere ibrido, o alterato; su una rinnovata concezione della malattia e della cura; sui limiti percettivi e sovente discriminatori del corpo dell’Altro; sulle disabilità e le alterazioni della sensorialità
“Contourner le vide: écriture et judéité(s) après la Shoah”, dir. F. DAINESE et E. QUAGLIA, Firenze, Giuntina, 2020, 123 pp.
No full textRecensione a volume miscellaneo dedicato alle ambivalenti tracce della judéité in vari autori di lingua francese del Novecento
Understanding the Properties of 3D Monolayers on Au25 Clusters
No full textThe study of the properties and applications of small gold monolayer-protected clusters (MPCs) is one of the most active research areas in nanosciences and nanotechnologies. MPCs are composed of a gold core surrounded by a capping monolayer usually consisting in thiolates and further Au atoms. This Thesis addresses aspects concerning the properties of the most important MPC displaying molecular behavior: Au25(SR)18. The main focus is on the structure and behavior of the capping thiolate monolayer, particularly in view of possible applications of these hybrid materials where the interaction between the gold core and the surrounding medium is dictated by the monolayer's properties themselves. The Thesis is structured as follows.
Chapter one provides a general introduction to MPCs, their size difference and how this factor affects their behavior, the main physicochemical properties of molecular MPCs, and finally the aims of this Thesis. This Chapter also includes a number of references. For practical reasons, however, each of the following Chapters contains its own references.
Chapter two describes the general synthesis and characterization of these clusters, whether in their native anionic state or as neutral, paramagnetic species obtained by controlled oxidation of the former. Four selected syntheses are described in detail. The control of the charge state and its effect on the optical and NMR properties are described. Finally, a general experimental section is provided. More details, however, will be added at the end of each Chapter, depending on the specific topic addressed.
Chapter three describes findings that have been published: Dainese, T.; Antonello, S.; Gascón, J. A.; Pan, F.; Perera, N. V.; Ruzzi, M.; Venzo, A.; Zoleo, A.; Rissanen, K.; Maran, F. Au25(SEt)18 , a Nearly Naked Thiolate-Protected Au25 Cluster: Structural Analysis by Single Crystal X-ray Crystallography and Electron Nuclear Double Resonance. ACS Nano 2014, 8, 3904-3912. We prepared and characterized a 25-gold atom nanocluster protected by the smallest ligand ever used, ethanethiol. The anionic and the neutral form of Au25(SEt)18 were fully characterized by ¹H and ¹³C NMR spectroscopy, which confirmed the monolayer's properties and the paramagnetism of neutral Au25(SEt)18. X-ray crystallography analysis of the latter provided the first structure of a gold cluster protected by a simple, linear alkanethiolate. The cluster was studied by advanced electron paramagnetic techniques and the results analyzed also by DFT calculations, which were not affected by structure's approximations or omissions.
Chapter four also describes findings that have been published: Antonello, S.; Arrigoni, G.; Dainese, T.; De Nardi, M.; Parisio, G.; Perotti, L.; René, A.; Venzo, A.; Maran, F. Electron Transfer through 3D Monolayers on Au25 Clusters. ACS Nano 2014, 8, 2788â2795. We prepared a large series of monodisperse Au25(SCnH2n+1)18 clusters (n = 2, 4, 6, 8, 10, 12, 14, 16, 18) and studied how electrons tunnel through these monolayers. Electron transfer results, nicely supported by ¹H NMR spectroscopy, IR absorption spectroscopy, and molecular dynamics results, show that there is a critical ligand length marking the transition between short ligands, which form a quite fluid monolayer structure, and longer alkyl chains, which self-organize into bundles. The monolayer protecting small gold nanoparticles is generally represented as the 3D equivalent of 2D SAMs on extended gold surfaces. We found, however, that at variance with the truly protecting 2D SAMs, efficient electronic communication of the Au25 core with the outer environment is thus possible even for long alkyl chains. These conclusions provide a different picture of how an ultrasmall gold core talks with the environment through/with its protecting but not-so-shielding monolayer.
Chapter five introduces a natural follow up of the previous Chapters. We used a series of linear-chain thiolate protected clusters having the general formula Au25(SCnH2n+1)18, with n = 3, 4, 5, 6, 8, and 10, and carried out conductivity measurements on their dry films, which were formed by drop casting these MPCs onto interdigitated electrodes (IDAs). The linear dependence of the conductivity on n points to a hopping mechanism where the cores of the nanoclusters behave as a localized electron-donor or acceptor site, and the ligands as spacers dictating the efficiency of electron tunneling. The experimental results were compared with those obtained for the same clusters in solution (Chapter 4). The electron-transfer results point to a substantial folding of the linear chains of these MPCs in the solid state, but to a lesser extent compared to what observed in solution, where more fluidity is possible.
Chapter six basically incorporates the most important results and methodologies described in the previous Chapters. We introduced branching (one methyl group in place of one hydrogen at position β with respect to the sulfur atom) along a butanethiolate chain, which thus introduces a stereogenic center. Although we used commercially available racemic thiols, we discovered that these thiols possess, in fact, an enantiomeric excess (e.e.) of the (S)-enantiomer, as verified through synthesis of the pure (S)-enantiomer. We prepared several Au25(SMeBu)18° clusters (HSMeBu = 2-methyl-1-butanethiol) and characterized them by various techniques. Among them, we used ¹H NMR spectroscopy and circular dichroism (CD) spectroscopy. Both techniques provided the same information: as the e.e. of the thiol employed reaches a value of ca. 75%, the resulting Au25 clusters only contain the S-thiolate. We thus observed, for the first time, the phenomenon of spontaneous resolution for an MPC. These conclusions based on spectral data were perfectly confirmed by solving the single crystal structure of a cluster that, in principle, should have contained thiols possessing 77% e.e. of the (S)-enantiomer. Instead, X-ray crystallography showed that only the (S)-enantiomer is capping the Au25 core
Does residence time affect responses of alien species richness to environmental and spatial processes?
No full textOne of the most robust emerging generalisations in invasion biology is that the probability of invasion increases with the time since introduction (residence time). We analysed the spatial distribution of alien vascular plant species in a region of north-eastern Italy to understand the influence of residence time on patterns of alien species richness. Neophytes were grouped according to three periods of arrival in the study region (1500–1800, 1800–1900, and > 1900). We applied multiple regression (spatial and nonspatial) with hierarchical partitioning to determine the influence of climate and human pressure on species richness within the groups. We also applied variation partitioning to evaluate the relative importance of environmental and spatial processes. Temperature mainly influenced groups with species having a longer residence time, while human pressure influenced the more recently introduced species, although its influence remained significant in all groups. Partial regression analyses showed that most of the variation explained by the models is attributable to spatially structured environmental variation, while environment and space had small independent effects. However, effects independent of environment decreased, and spatially independent effects increased, from older to the more recent neophytes. Our data illustrate that the distribution of alien species richness for species that arrived recently is related to propagule pressure, availability of novel niches created by human activity, and neutral-based (dispersal limitation) processes, while climate filtering plays a key role in the distribution of species that arrived earlier. This study highlights the importance of residence time, spatial structure, and environmental conditions in the patterns of alien species richness and for a better understanding of its geographical variation
Una loquace reticenza. Raymond Federman tra memoria e invenzione
No full textMy article re-read Federman's trilogy by focusing on some leading themes of Holocaust literature: emptiness and absence, memory and oblivion. It will strongly emerge the capital role of literature as a recover from wounds and as a memory-building
"Nullus invitis detur episcopus": The Origin of a Formula in the Epistolary of Leo the Great
No full textThis paper aims to deepen knowledge of some aspects of Leo the Great’s governance of Eastern Illyria. It deals with the theme of episcopal elections in the fifth century according to the letters of Pope Leo. In particular, it takes into account his epistle 14 and Leo’s solution to the crisis concerning the See of Thessalonica a few years before the Council of Chalcedon. This analysis will clarify the framework out of which the formula “nullus invitis detur episcopus” emerged
Epilessia
No full textIl testo è strutturato in maniera logica, partendo dalla semeiotica clinica e laboratoristica per passare poi alla trattazione più dettagliata delle malattie neurologiche divise sia su base anatomica che patofisiologica
MODULATION OF THE ENZYMATIC ACTIVITY AND MEMBRANE BINDING PROPERTIES OF SOYBEAN LIPOXYGENASE-1 THROUGH LIMITED PROTEOLYSIS AND METAL SUBSTITUTION
No full textLipoxygenases are non-heme, non-sulfur iron containing enzymes that catalyze the dioxygenation of polyunsatured fatty acids containing one or more pentadiene systems to the corresponding hydroperoxy derivatives. Structural studies in solution of the mammalian and plant enzyme revealed that the latter has a more stable and compact conformation1. As yet, metal atom extraction, reconstitution and substitution with vicariate metals have not been successfully applied to soybean lipoxygenase-1, because of the highly buried position of the iron atom within the active site. Tryptic digestion of lipoxygenase-1 and the subsequent isolation of the 60 kDa C-terminal region allowed to generate a “mini-lipoxygenase-1 (miniLOX)” that retains the catalytically active iron, but in a more accessible position2. In this study, we investigated by near-UV-circular dichroism and fluorescence spectroscopies the structural and functional effects of iron removal, reconstitution and vicariation in miniLOX. Moreover, we report the kinetic analysis and the membrane binding ability of the apo- and metal-substituted forms of miniLOX, using fluorescence resonance energy transfer and monolamellar vesicles. Taken together, these data demonstrate an unprecedented structural role of iron, which is involved not only in the catalytic activity but also in the membrane binding ability of lipoxygenase-1.1. Dainese E. Sabatucci A. van Zadelhoff G. Angelucci C. B. Vachette P., Veldink G. Finazzi Agrò A. and Maccarrone M. (2005). J. Mol. Biol. 349, 143-152.2. Maccarrone M. Salucci M. L. van Zadelhoff G. Malatesta F. Veldink, G. Vliegenthart J. F. and Finazzi Agrò A. (2001). Biochemistry 40, 6819-6827.[...
- …
