72 research outputs found
Personal libraries of eminent historic figures: a comparison between Italy and USA
Il dibattito critico italiano sulle biblioteche d'autore si Ăš intensificato nel primo decennio del XXI secolo. In precedenza le riflessioni sullâargomento erano state sporadiche e caratterizzate da un taglio umanistico piuttosto che da un'impostazione biblioteconomica: i fondi personali venivano studiati in ragione dei singoli pezzi rari o preziosi che conservavano, oppure con finalitĂ bibliografiche, biografiche, storiche, letterarie o filologiche. I convegni e i seminari che si sono susseguiti tra il 2000 e il 2009 si sono invece focalizzati sulla definizione del concetto di biblioteca d'autore, sulla descrizione dei suoi elementi distintivi e sulle problematiche concernenti il trattamento biblioteconomico dei documenti in esse conservati nel momento in cui queste biblioteche da private diventano aperte e fruibili al pubblico. In area francese e anglosassone invece si continua a mantenere la tradizionale impostazione umanistica sullâargomento: lâunica eccezione Ăš unâindagine condotta nel 2010 tra le biblioteche dellâAssociation of Research Libraries (ARL) con lo scopo di rilevare le procedure tecniche adottate nelle biblioteche dâautore.Lâarticolo analizza e confronta le soluzioni organizzative e gestionali adottate in Italia e nelle biblioteche afferenti allâAssociation of Research Libraries: gli strumenti utilizzati per renderle visibili in rete (OPAC, strumenti di ricerca, Web 2.0 ecc.), la scelta di mantenere o meno lâordinamento originario, la catalogazione dâesemplare (caratteristiche, finalitĂ , normativa di riferimento e scelte catalografiche). In particolare, si sofferma sulle novitĂ introdotte dalle Reicat per la catalogazione dâesemplare. Il confronto fra realtĂ italiana e realtĂ americana mette in luce il ritardo delle biblioteche statunitensi nella corretta gestione e valorizzazione delle biblioteche personali.In Italy, the debate on personal libraries of eminent historic figures intensified in the first decade of 21st century. While the occasional previous studies on the subject were mostly conducted from a liberal arts point of view (i.e. personal libraries were studied either for their rare and precious documents or for bibliographical, biographical, historical, literary and philological purposes) the studies undertaken since 2000 focus on the concept of biblioteca dâautore: its definition, its distinctive features, and what must be done when a private library becomes open to the public. On the other side, the liberal arts approach is still prevailing in English-speaking countries and France, with the exception of a 2010 survey conducted among ARL (Association of Research Libraries) member libraries, investigating the technical procedures applied to personal libraries.This paper analyzes and compares the Italian organization and management process practices and the ARL member libraries practices: the tools employed to ensure visibility in the Internet (OPAC, discovery tools, Web 2.0 tools etc.), the choice between maintenance or alteration of the original organization, the item-level cataloging (characteristics, purposes, standards and cataloging choices). In particular, it focuses on the innovations introduced by the REICAT (Italian rules of cataloging) in the item-level cataloging. In conclusion, today Italy seems to be a step forward USA in the proper management and promotion of personal libraries
Noncovalent passivation of supported phosphorene for device applications: from morphology to electronic properties
An interface between poly(methyl-methacrylate) PMMA-supported phosphorene and layers of linear alkane chains has been studied computationally to reveal an efficient route to noncovalent passivation in terms of the effective coverage of surface area. The formation of strongly ordered compact planar aggregates of alkanes driven by the anisotropy of the phosphorene surface greatly improves the packing at the interface. Small mechanical deformations of the phosphorene structure induced by the interaction with PMMA substrate, a polymer dielectric material, do not alter substantially the mechanical, electronic properties of phosphorene. This indicates remarkable possibilities of using alkanes for prevention of phosphorene from surface degradation phenomena and suggests new technological routes for the fabrication of phosphorene-based electronic devices
First archaeological evidence for ginger consumption as a potential medicinal ingredient in a late medieval leprosarium at St Leonard, Peterborough, England
Leprosy was one of the most outwardly visible diseases in the European Middle Ages, a period during which leprosaria were founded to provide space for the sick. The extant documentary evidence for leprosy hospitals, especially in relation to diet, therapeutic, and medical care, is limited. However, human dental calculus stands to be an important source of information as it provides insight into the substances people were exposed to and accumulated in their bodies during their lives. In the present study, microremains and DNA were analysed from the calculus of individuals buried in the late medieval cemetery of St Leonard, a leprosarium located in Peterborough, England. The results show the presence of ginger (Zingiber officinale), a culinary and medicinal ingredient, as well as evidence of consumption of cereals and legumes. This research suggests that affected individuals consumed ingredients mentioned in medieval medical textbooks that were used to treat regions of the body typically impacted by leprosy. To the authors' knowledge, this is the first study which has identified Zingiber officinale in human dental calculus in England or on the wider European continent
Steric and electronic control of 1,3-dipolar cycloaddition reactions in carbon nanotube nanoreactors
The use of single-walled carbon nanotubes as effective nanoreactors for preparative bimolecular reactions has been demonstrated for the first time. We show that the extreme spatial confinement of guest reactant molecules inside host carbon nanotubes increases the regioselectivity for 1,4-triazole in thermally initiated azideâalkyne cycloaddition reactions. Through comparison of the internal dimensions of the nanotube and the steric bulk of the reactants, we demonstrate that the formation of the more linear 1,4-regioisomer can be enhanced by up to 55% depending on the extent of spatial restrictions imposed within the nanoreactors. Furthermore, through systematic variation of the substituents in the para-position of the alkyne reactants, we reveal the unexpected influence of the reactantsâ electronic properties on the regioselectivity of reactions within nanoreactors, which act to either oppose or promote the preferential formation of the 1,4-regioisomer induced by steric effects, reflecting the unique ability of carbon nanotubes to stabilize the dipole moment of confined reactants. Thus, we show that the observed regioselectivity of azideâalkyne cycloaddition reactions confined within carbon nanotube nanoreactors reflects a subtle interplay between both steric and electronic factors
Adsorption of Hexacontane on Hexagonal Boron Nitride
© 2018 American Chemical Society. We have investigated the adsorption of hexacontane (C60H122) on hexagonal boron nitride (hBN) using atomic force microscopy (AFM). The molecules can be deposited either by sublimation or from solution and form lamellar rows with dimensions of the order of 0.1-1 Όm in three different rotational domains. High-resolution AFM images reveal that, similar to alkanes on graphite, the molecules are adsorbed parallel to the lattice vectors of hBN and we show using molecular mechanics that this corresponds to the lowest energy configuration. Lamellar rows with the same periodicity are observed even when several layers of hexacontane are deposited, although there is some orientational disorder in these multilayers. We also observe heat-induced modification of hexacontane, including recrystallization. We compare our results with recent X-ray studies of alkane adsorption on hBN and discuss the possible role of alkanes on steering molecular self-assembly on hBN
Rational Design of a Famotidine-Ibuprofen Coamorphous System: An Experimental and Theoretical Study
Famotidine (FMT) and ibuprofen (IBU) were used as model drugs to obtain coamorphous systems, where the guanidine moiety of the antacid and the carboxylic group of the nonsteroidal anti-inflammatory drug could potentially participate in H-bonds leading to a given structural motif. The systems were prepared in 3:7, 1:1, and 7:3 FMT and IBU molar ratios, respectively. The latter two became amorphous after 180 min of comilling. FMT-IBU (1:1) exhibited a higher physical stability in assays at 4, 25, and 40 °C up to 60 days. Fourier transform infrared spectroscopy accounted for important modifications in the vibrational behavior of those functional groups, allowing us to ascribe the skill of 1:1 FMT-IBU for remaining amorphous to equimolar interactions between both components. Density functional theory calculations followed by quantum theory of atoms in molecules analysis were then conducted to support the presence of the expected FMT-IBU heterodimer with consequent formation of a R28 structural motif. The electron density (Ï) and its Laplacian (2 Ï) values suggested a high strength of the specific intermolecular interactions. Molecular dynamics simulations to build an amorphous assembly, followed by radial distribution function analysis on the modeled phase were further employed. The results demonstrate that it is a feasible rational design of a coamorphous system, satisfactorily stabilized by molecular-level interactions leading to the expected motif.Fil: Russo, Marcos Guillermo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - San Luis. Instituto de Investigaciones en TecnologĂa QuĂmica. Universidad Nacional de San Luis. Facultad de QuĂmica, BioquĂmica y Farmacia. Instituto de Investigaciones en TecnologĂa QuĂmica; ArgentinaFil: Baldoni, Hector Armando. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - San Luis. Instituto de MatemĂĄtica Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias FĂsico, MatemĂĄticas y Naturales. Instituto de MatemĂĄtica Aplicada de San Luis "Prof. Ezio Marchi"; Argentina. Universidad Nacional de San Luis. Facultad de QuĂmica, BioquĂmica y Farmacia; ArgentinaFil: Davila, Yamina Andrea. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - San Luis. Instituto de Investigaciones en TecnologĂa QuĂmica. Universidad Nacional de San Luis. Facultad de QuĂmica, BioquĂmica y Farmacia. Instituto de Investigaciones en TecnologĂa QuĂmica; ArgentinaFil: Brusau, Elena Virginia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - San Luis. Instituto de Investigaciones en TecnologĂa QuĂmica. Universidad Nacional de San Luis. Facultad de QuĂmica, BioquĂmica y Farmacia. Instituto de Investigaciones en TecnologĂa QuĂmica; Argentina. Universidad Nacional de San Luis. Facultad de QuĂmica, BioquĂmica y Farmacia; ArgentinaFil: Ellena, Javier A.. Universidade de Sao Paulo; BrasilFil: Narda, Griselda Edith. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - San Luis. Instituto de Investigaciones en TecnologĂa QuĂmica. Universidad Nacional de San Luis. Facultad de QuĂmica, BioquĂmica y Farmacia. Instituto de Investigaciones en TecnologĂa QuĂmica; Argentin
Synthesis and characterisation of rylene diimide dimers using molecular handcuffs
A strategy for positioning, and loosely connecting, molecules in close proximity using mechanically interlocked handcuffs is described. The strategy is demonstrated using rylene diimides, creating dimeric structures in which two components are linked through pillar[5]arene/imidazolium rotaxanes. Investigation of the resulting molecules demonstrates intriguing and new properties that arise from placing these redox active dye molecules together, allowing interactions, whilst allowing the molecules to separate as required. In particular we observe excimer emission from a perylene diimide dimer handcuff and the formation of an unusual radical anion Ï-dimer upon double reduction of the same molecule. The latter exhibits a unique visible absorption profile for a PDI-based molecule. We demonstrate the flexibility of our approach by making an unprecedented mixed perylene diimide/naphthalene diimide dimer which also reveals interactions between the two components. Our synthetic strategy facilitates the creation of unusual dimeric structures and allows the investigation of intermolecular interactions and the effects they have on electronic and magnetic properties
Structural analysis of Xanthan GUM-FE (III) capsules
In this work, the formation of capsules in xanthan gum and complexing solutions of Fe III is structurally evaluated. These capsules have a spheroid shape that, when dried, collapse into disc shapes. These spheroids are made up of microspheres that partially explain this collapse. The backscattered SEM image shows areas rich in Fe and others poorer in this metal, the EDX analysis confirms this. FTIR chromatograms show a clear shift at approximately 1620 cm-1 due to the formation of the xanthan gum-Fe III complex. This work also proposes a structure, theoretically demonstrated, between xanthan gum and Fe III, which can explain what the biopolymeric structure bending procedure is like due to the presence of Fe III, a model called TransbiHook.Fil: VĂĄsquez, Elena. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mendoza. Instituto de HistologĂa y EmbriologĂa de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias MĂ©dicas. Instituto de HistologĂa y EmbriologĂa de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Piguillem Palacios, SofĂa Viviana. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - San Luis. Instituto de QuĂmica de San Luis. Universidad Nacional de San Luis. Facultad de QuĂmica, BioquĂmica y Farmacia. Instituto de QuĂmica de San Luis; ArgentinaFil: Rubio, Santiago. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - San Luis. Instituto de Investigaciones en TecnologĂa QuĂmica. Universidad Nacional de San Luis. Facultad de QuĂmica, BioquĂmica y Farmacia. Instituto de Investigaciones en TecnologĂa QuĂmica; ArgentinaFil: Diaz, Jorge RamĂłn Abel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - San Luis. Instituto de Investigaciones en TecnologĂa QuĂmica. Universidad Nacional de San Luis. Facultad de QuĂmica, BioquĂmica y Farmacia. Instituto de Investigaciones en TecnologĂa QuĂmica; ArgentinaFil: Baldoni, Hector Armando. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - San Luis. Instituto de MatemĂĄtica Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias FĂsico, MatemĂĄticas y Naturales. Instituto de MatemĂĄtica Aplicada de San Luis "Prof. Ezio Marchi"; ArgentinaFil: Vega, Enrique. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - San Luis. Instituto de Investigaciones en TecnologĂa QuĂmica. Universidad Nacional de San Luis. Facultad de QuĂmica, BioquĂmica y Farmacia. Instituto de Investigaciones en TecnologĂa QuĂmica; ArgentinaFil: Masuelli, Martin Alberto. Universidad Nacional de San Luis. Facultad de QuĂmica, BioquĂmica y Farmacia; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - San Luis. Instituto de FĂsica Aplicada "Dr. Jorge AndrĂ©s Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias FĂsico MatemĂĄticas y Naturales. Instituto de FĂsica Aplicada "Dr. Jorge AndrĂ©s Zgrablich"; Argentin
Ordering, Flexibility and Frustration in Arrays of Porphyrin Nanorings
The regular packing of atoms, molecules and nanoparticles provides the basis for the understanding of structural order within condensed phases of matter. Typically the constituent particles are considered to be rigid with a fixed shape. Here we show, through a combined experimental and numerical study of the adsorption of cyclic porphyrin polymers, nanorings, on a graphite surface, that flexible molecules can exhibit a rich and complex packing behaviour. Depending on the number of porphyrin sub-units within the nanoring we observe either a highly ordered hexagonal phase or frustrated packing driven by directional interactions which for some arrangements is combined with the internal deformation of the cyclic polymer. Frustration and deformation occur in arrays of polymers with ten sub-units since close packing and co-alignment of neighbouring groups cannot be simultaneously realised for nanorings with this internal symmetry. *[email protected]
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