102,183 research outputs found
Restauro e Ampliamento Banca d'Albania.
No full textM. Petreschi (capogruppo), N. Valentin, G. Amadei, M. Pascucci (gruppo di progettazione) importante edifico storico a Tirana, Albani
On the use of the quasi-Gaussian entropy theory in the study of simulated dilute solutions
No full textIn a recent paper [M. D'Alessandro, M. D'Abramo, G. Brancato, A. Di Nola, and A. Amadei, J. Phys. Chem. B 106, 11843 (2002)] we showed how to combine molecular dynamics simulations with the quasi-Gaussian entropy theory, in order to model the statistical mechanics and thermodynamics of ionic (water) solutions. In this paper we extend the method to treat nonspherical solutes, describe more thoroughly its theoretical basis and apply it to a set of more complex solute molecules in water (i.e., water, methane, ethane, methanol, and ethanol). Results show that this approach can really provide an excellent theoretical description of solute-solvent systems over a wide range of temperatures. (C) 2004 American Institute of Physics
A theoretical study on the spectral and electrochemical properties of Ferrocene in different solvents
No full textA theoretical-computational study based on Molecular Dynamics simulations and Perturbed Matrix Method (MD-PMM) calculations was carried out for evaluating some properties of solvated Ferrocene including the UV-Vis spectrum and the redox potential. The results, in rather good agreement with the experimental values, display that Ferrocene low-lying excited states are scarcely affected by the change of solvent polarity. On the other hand, the Ferrocene/Ferricinum redox potential show a sharp, although not dramatic, dependency on the nature of the solvent essentially because of the sensitivity of the charged Ferricinium species to the solvent electric field fluctuation. The present study is the first one theoretically addressing, with the use of explicit solvent calculations, the Ferrocene UV spectrum and the Ferricinium/Ferrocene couple redox potential, a quantity proposed by the IUPAC Electrochemical Commission as reference electrode potential for non-aqueous solutions. (c) 2013 Elsevier B.V. All rights reserved
Behind the developing brains and beating hearts of stem cell-derived embryo models
No full textStudies over the past decade have shown how stem cells representing embryonic and extra-embryonic tissues of the mouse can self-assemble in the culture dish to recapitulate an astonishing part of early embryonic development. A systematic analysis has demonstrated how pluripotent embryonic stem cells can be induced to behave like the implanting epiblast; how they can interact with trophectoderm stem cells to form a patterned structure resembling the implanting embryo prior to gastrulation; and how the third stem cell type - extra-embryonic endoderm cells - can be incorporated to generate structures that undergo the cell movements and gene expression patterns of gastrulation. Moreover, such stem cell-derived embryo models can proceed to neurulation and establish progenitors for all parts of the brain and neural tube, somites, beating heart structures and gut tube. They develop within extra-embryonic yolk sacs that initiate haematopoiesis. Here we trace this journey of discovery
Quantification of character-impacting compounds in Ocimum basilicum and 'Pesto alla Genovese' with selected ion flow tube mass spectrometry
No full textBasil (Ocimum basilicum) is an important flavourant plant which constitutes the major ingredient of the pasta sauce 'Pesto alla Genovese'. The characteristic smell of basil stems mainly from a handful of terpenoids (methyl cinnamate, eucalyptol, linalool and estragole), the concentration of which varies according to basil cultivars. The simple and rapid analysis of the terpenoid constituents of basil would be useful as a means to optimise harvesting times and to act as a quality control process for basil-containing foodstuffs. Classical analytical techniques such as gas chromatography/mass spectrometry (GC/MS) are, however, slow, technically demanding and therefore less suitable for routine analysis. A new chemical ionisation technique which allows real-time quantification of traces gases, Selected Ion Flow Tube Mass Spectrometry (SIFT-MS), was therefore utilised to determine its usefulness for the assay of terpenoid concentrations in basil and pesto sauce headspace. Trace gas analysis was performed using the NO+ precursor ion which minimised interference from other compounds. Character-impacting compound concentration was measured in basil headspace with good reproducibility and statistically significant differences were observed between cultivars. Quantification of linalool in pesto sauce headspace proved more difficult due to the presence of interfering compounds. This was resolved by careful selection of reaction product ions which allowed us to detect differences between various commercial brands of pesto. We conclude that SIFT-MS may be a valid tool for the fast and reproducible analysis of flavourant terpenoids in basil and basil-derived foodstuffs. © 2012 John Wiley & Sons, Ltd
The reactions of a series of terpenoids with H3O+, NO+and O2+ studied using selected ion flow tube mass spectrometry
No full textThe reactions of H3O+, NO+ and O 2+ with twelve terpenoids and one terpene, all of which occur naturally in plants and which possess important smell and flavourant properties, were characterized using Selected Ion Flow Tube Mass Spectrometry (SIFT-MS). The H3O+ reactions resulted primarily in the formation of the proton transfer product and occasionally in a water elimination product. The NO+ reactions instead generated the charge transfer product or NO+ adducts, and occasionally alkyl fragments, or resulted in hydride abstraction. Reaction with O2+ caused a higher fragmentation of the terpenoids with the molecular ion being the minor product of most reactions. Identification and quantification of each compound in complex mixtures are probably possible in most cases using the H3O + and/or NO+ precursors while O2+ may be useful for isomer discrimination. Our data suggests that SIFT-MS may be a useful tool for the rapid analysis of these compounds in plants and derived foodstuffs. Copyright © 2010 John Wiley & Sons, Ltd
Cooperative di produzione e agricoltura di gruppo
No full textIl volume analizza la presenza della cooperazione all'interno dell'agricoltura italiana attraverso numerose ricerche e saggi
The Ni3Sn4 intermetallic as a novel electrode in lithium cells
No full textA Ni3Sn4 intermetallic compound has been prepared and tested as a new type of anode material. The results show that this compound may be cycled in a lithium cell with a reversible capacity of about 250 mAh g(-1). This feature, combined with the low cost and the compatibility with the environment, makes Ni3Sn4 a material of interest for practical applications. (c) 2004 Published by Elsevier B.V
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