1,783 research outputs found
Usi e riusi della scultura medievale in età moderna, a cura di Laura Cavazzini, Clario Di Fabio, Paola Vitolo, Cimorelli, Milano 2023.
No full textReimpiego, rifunzionalizzazione, riallestimento della scultura medievale in Età moderna: analisi del fenomeno in sei regioni italian
Introduction to "Numerical determination of the competitive isotherm of enantiomers" by A. Felinger, A. Cavazzini, G. Guiochon [J. Chromatogr. A 986 (2003) 207-225]
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Alla ricerca dell'eternità. Dipingere sulla pietra e con la pietra a Roma. Itinerari
No full textItinerario dei luoghi in cui sono conservate le principali opere di pittura su pietra a Roma
Meraviglia senza tempo. Pittura su pietra a Roma tra Cinquecento e Seicento.
No full textNella Vita dedicata a Sebastiano del Piombo, Giorgio Vasari scrive: [...] «ha lavorato sopra le pietre di peregrini, di marmi, di mischi, di porfidi e lastre durissime, nelle quali possono lunghissimo tempo durare le pitture; oltre che cio ha mostrato, come si possa dipingere sopra l’argento, rame, stagno e altri metalli». Nel breve passaggio appare la motivazione attribuita a questo uso innovativo dei materiali: la possibilità di protrarre la vita dell'opera, di renderla, come scriveranno altri autori, «poco meno che eterna». A questo tipo di pittura, ai suoi sviluppi e alle sue implicazioni storiche e semantiche nel corso del Seicento, la Galleria Borghese dedicherà una mostra nell'autunno del 2022. Nel corso del Cinquecento, la discussione sulla durabilità delle opere d’arte si era inserita nel dibattito sul paragone, opponendo i pregi della scultura a quelli della pittura. Il confronto fra le due arti, all’inizio del Seicento, avviene all’interno delle collezioni, nuovi spazi del dibattito storico artistico. Si infittisce il gioco fra le arti sorelle: gli scultori usano marmi colorati e i pittori dipingono su pietra (lavagna, lapislazzuli, pietra paesina, ecc.), mentre metalli e legni preziosi concorrono alla creazione di oggetti straordinari, come piccoli altari, stipi e orologi, dalle forme architettoniche complesse e adorni di sculturine, rilievi e pittura. Alcuni di questi oggetti, nei quali pietra e metalli erano impiegati non solo per la durabilità dei materiali, ma per il loro valore e per la loro stupefacente fattura, la cui bellezza stessa dava il senso di trascendere le epoche, saranno parte della mostra, integrandosi con quelli che facevano parte della collezione di Scipione Borghese, oggi ancora in galleria
Introduzione a: Reimpiego, rilavorazione, rifunzionalizzazione: la “lunga vita” della scultura medievale nei cantieri di Età moderna, a cura di Paola Vitolo, Clario Di Fabio, Laura Cavazzini, in «Mélanges de l’École française de Rome» 2021, 133/1, pp. 1-120.
No full textMETODOLOGIE CROMATOGRAFICHE NELLO STUDIO DEI PROCESSI DI ADSORBIMENTO
No full textIn analytical chromatography, the sample we analyze is usually rather dilute and allows
the development of a rather straightforward method. Due to the minute concentrations we
deal with in analytical chromatography, we face a linear behavior. The retention time of
the analytes and the selectivity of a given separation can be forecast by simple rules that
tremendously help us to develop efficient and fast separations. However, when we increase
the sample size and a finite amount of sample is introduced in a chromatographic column,
we leave the shelter of linear chromatography and have to cope with more complex peak
shapes and phenomena.
When the amount of the sample is comparable to the adsorption capacity of the
zone of the column the migrating molecules occupy, the analyte molecules compete for
adsorption on the surface of the stationary phase. The molecules disturb the adsorption
of other molecules, and that phenomenon is normally taken into account by nonlinear
adsorption isotherms. The nonlinear adsorption isotherm arises from the fact that the
equilibrium concentrations of the solute molecules in the stationary and the mobile phases
are not directly proportional. The stationary phase has a finite adsorption capacity;
lateral interactions may arise between molecules in the adsorbed layer, and those lead
to nonlinear isotherms. If we work in the concentration range where the isotherms are
nonlinear, we arrive to the field of nonlinear chromatography where thermodynamics
controls the peak shapes. The retention time, selectivity, plate number, peak width,
and peak shape are no longer constant but depend on the sample size and several other
factors. In addition to be a fundamental piece of information to modeling and optimizing
preparative separations, adsorption isotherm determination is the key to study analytestationary
phase interactions. Besides they allow for the characterization in terms of
adsorption energy distribution of the surface heterogeneity. If biomolecules (peptides,
proteins, etc.) or molecules with biological activity (such as drugs, etc.) were chemically
bound to the stationary phase one speaks in terms of bioaffinity chromatography. In
these cases, adsorption isotherm measurements are a powerful tool to study molecular
recognition processes between the adsorbed biomolecules and any analyte injected into
the chromatographic column.
During this PhD thesis, different aspects of fundamentals of adsorption processes at
the liquid-solid interface have been considered. In parallel, we focused on the setup of
instrumental techniques for the automatic determination of adsorption isotherms.
For that which concerns the study of fundamentals of adsorption, stationary phases
traditionally employed in liquid chromatography (C18) have been characterized by investigating
the adsorption from binary mixtures of compounds with different chemico-physical
properties. This kind of study was essentially realized by measuring excess isotherms.
Through them, the preferential adsorption of one component with respect to the other
constituting the mixture can be determined. These studies are important to understand
the role of so-called organic modifiers in the chromatographic separation process. In fact,
in reversed phase chromatography the organic modifier is usually considered as a mean
to increase mobile phase analyte solubility, while its active role in the adsorption process
is often underestimated.
We then focused on bioaffiniy recognition studies by applying nonlinear concepts to
the characterization of adsorption of peptides and dipetides on a macrocyclic antibiotic
(Teicoplanin) chemically bounded to silica gel. It was demonstrated that nonlinear
chromatography can be considered a valid alternative to other techniques in use for the
determination of binding constants (such as ELISA, Surface Plasmon Resonance, etc.).
The fundamental advantage of nonlinear studies is that they permit to distinguish between
selective and non-selective interactions in the molecular recognition process, which
is not achievable by other investigation techniques.
Adsorption equilibria of insulin (a relatively small protein, about 5800 Da) in different
experimental conditions were studied with the purpose of understanding the mechanisms
responsible for the chromatographic behavior of this protein. In fact, insulin retention
is characterized by a very large sensitivity to the mobile phase composition. Nonlinear
adsorption data were coupled with circular dichroism and mass spectrometry measurements.
Our purpose was to understand if tertiary structure modifications or agglomerate
formation (dimers, trimers, etc.) could be at the origin of the observed phenomena.
Besides thermodynamic aspects, kinetic phenomena are fundamental to characterize
the chromatographic process. In chromatography, in particular, we refer to mass transfer
kinetics, that is the ensemble of the processes involved in the transfer of solute molecules
from the mobile to the stationary phase. In chromatography, these include axial dispersion
(molecular and eddy diffusion), external and internal mass transfer (pore diffusion
and surface diffusion), and adsorption-desorption kinetics. In this work, mass transfer
phenomena on a new kind of monolithic columns, obtained through gamma-ray polymerization,
were studied. The combined use of Van Deemter and kinetic plots allowed to
correlate column efficiency to the length of cross-linkers used in polymerization.
In addition to these fundamental studies, the other part of this work was about the
set-up of instrumentation for different kinds of purposes. A pseudo-bidimensional system
that allows for the deconvolution and online sampling of chromatographic peaks measured
under nonlinear and gradient conditions was developed. The importance of this system is
that it permits to achieve the information necessary for the determination of adsorption
isotherms in an optimized and automatic manner by exploiting numerical procedures,
known in literature as inverse methods. A second application was in the field of pharmaceutics.
By using a system which combines size exclusion and polar reversed-phase
columns, a method for the simultaneous purification and determination of iomeprol, a
radiopharmaceutical analyte, in human plasma was developed and validated
Arte in facciata: le decorazioni pittoriche e scultoree nei processi di trasformazione urbana ed architettonica
No full textWithin the complex phenomena of reconstruction and restoration of buildings that accompany
the processes of urban transformation, the external pictorial and sculptural decorations play a
role of great importance.
The facades, as liminal surfaces, denounce both the intended uses and the political, social
and cultural implications that accompany the functions of the buildings, also communicating
the requests, claims, ambitions of the owners and users (individuals, groups, communities or
institutions). For these reasons, they are the witnesses of continuity of use and persistence of
values, or the expression of new meanings and life styles.
At the same time, the facades represent the scenic backgrounds of urban perspectives, but
also of religious, civic and cultural events, and as such they are called to adapt to more
general urban renewal plans: they are, therefore, often expected to support needs in a
certain sense ‘imposed’ by the use of the spaces outside them. Both in large cities and in
small towns, the transformations of the façades are conducted as a spontaneous enterprise
focused on the single monument or are planned on the wide urban scale, sometimes after
dramatic events (wars, earthquakes, etc.). Documented only by written sources or sometimes
also by material traces, changes and transformations represent an eloquent ‘manifesto’ of the
processes of the historical memory, of the dynamics that accompany them, of the social
instances and cultural impulses that determine them.
The essays of this session analyse a wide range of cases in different chronological and
geographical contexts, which reveal the role played by the façade decorations and related
transformations as an expression and representation of the human and material history of the
cities and of their spaces.
The theme of the session falls within the area of interest of the the project Memory and
identity. Reuse, reworking and rearrangement of the Medieval sculpture in the Modern Age
between historical research and new technologies, FISR 2019_05012
Bioactive compounds analysis in food matrices and waste products
No full textFood and nutrition research have grown exponentially over the past two decades, changing the way food is considered. In fact, it is no longer considered simply energy for the body but provides components with specific functions and nutritional properties, which include potential benefits, as well as possible harmful effects on health; among these, fatty acids, vitamins, phenolic acids, and flavonoids have been studied in recent years. In recent years, proteins, peptides and lipids have also played an important role in the study of components with high nutritional value, giving way to a new branch of the omic sciences, namely nutritional proteomics (nutriproteomics) and lipidomics. The study of bioactive peptides present in various food products represents a new field of research and field of application of proteomic analysis. Some peptides are able to trigger physiological activities that promote skin health, such as stimulating collagen synthesis, controlling angiogenesis and melanogenesis and modulating cell proliferation. Peptides are often classified as multifunctional peptides, i.e. they are capable of inducing more than one physiological activity. These characteristics make them suitable for use as therapeutic agents in the pharmaceutical field or as functional compounds, food additives, bio-preservatives in the field of nutraceuticals. These peptides can be released in different ways: they can be naturally present (i.e. endogenous) in matrices due to the presence of enzymes or bacteria, they can be released during gastrointestinal digestion, they can be formed following processes that occur in foods such as maturation, fermentation, storage or cooking, or by in vitro hydrolysis with the selection of a specific and appropriate enzyme. Except in the case in which the digestion is carried out in vitro by site-specific proteases, the obtained peptides can have a wide range of terminal amino acids and sizes. Of interest are both the bioactive peptides derived from enzymatic digestion, but also the short peptides naturally present within the matrix. Another very interesting class of molecules, not widely studied but specifically analyzed in this work are: seleno-amino acids. These compounds regulate many biological activities, and are important against various diseases. Another important goal is the study of waste. This type of product is normally seen as a problem for the economy and the environment, because it must be disposed of waste could be better used, though, not only as feed for animals but, for example, as a source of bioactive compounds. Therefore, the purpose of this doctoral project was to develop effective and innovative analytical strategies for the study of bioactive molecules and identification of compounds not abundant or not yet identified in different food matrices
Kinetic theories of liquid chromatography
No full textKinetic theories of liquid chromatography play a key role in evaluating the performance of stationary phases. The conventionally used plate height equations and the band broadening occurring in the different areas of liquid chromatography are accounted for by kinetic models. In this chapter, the most important macroscopic (lumped kinetic, lumped pore, and general rate) and microscopic (stochastic-dispersive) models are discussed. The plate height equations arising from those kinetic models are discussed and compare
Post-processing methods of PIV instantaneous flow fields for unsteady flows in turbomachines
No full textThe Particle Image Velocimetry is undoubtedly one of the most important technique in Fluid-dynamics since it allows to obtain a direct and instantaneous visualization of the flow field in a non-intrusive way. This innovative technique spreads in a wide number of research fields, from aerodynamics to medicine, from biology to turbulence researches, from aerodynamics to combustion processes. The book is aimed at presenting the PIV technique and its wide range of possible applications so as to provide a reference for researchers who intended to exploit this innovative technique in their research fields. Several aspects and possible problems in the analysis of large- and micro-scale turbulent phenomena, two-phase flows and polymer melts, combustion processes and turbo-machinery flow fields, internal waves and river/ocean flows were considered
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