91 research outputs found
Suoni e strumenti dei Sami nel Viaggio settentrionale di Francesco Negri (1663-1666) e nell'immaginario musicale seicentesco
EnBetween 1663 and 1666, priest Francesco Negri from Ravenna widely explored the Scandinavian peninsula, for the first time reaching the North Cape from continental Europe. The goal of the trip was political and religious: the priest had probably been sent secretly to Stockholm by the French Embassy to lead a religious mission in a country considered a bulwark of Lutheranism, interrogating Catholics and bringing their confessions to Tridentine Europe. The report was written according to the perspective of Seventeenth-century natural philosophy, which can be clearly noticed through the attention paid by the author towards the sounds of the animals and the natural world. But above all, it is the part devoted to the Sami people which testifies the spread through Seventeenth-century continental Europe of the iconographic model of the typical Sami musical instrument, the drum for shamanic rituals, which is carefully described and illustrated in the text.ItTra il 1663 e il 1666 il sacerdote Francesco Negri di Ravenna compie una vasta esplorazione della penisola scandinava raggiungendo per la prima volta Capo Nord dall’Europa continentale. L’intento sotteso al viaggio è probabilmente politico-religioso: il sacerdote pare fosse stato inviato a Stoccolma in segreto dall’ambasciata francese per condurre una missione religiosa in un paese ritenuto baluardo del luteranesimo, al fine di interrogare i cattolici e portarne le confessioni nell’Europa tridentina. La prospettiva del resoconto è debitrice della filosofia naturale secentesca: essa emerge nell’attenzione dell'Autore verso le sonorità legate al mondo naturale e al mondo animale. Ma è soprattutto la parte dedicata ai Sami che testimonia la diffusione nell'Europa continentale secentesca di un modello iconografico legato allo strumento musicale tipico sami, il tamburoper i rituali sciamanici, che viene ampiamente descritto nel testo con il corredo di diverse tavole disegnate
Darwin non deve andare a scuola
After its remarkable affirmation overseas, creationism has landed in Europe and is also present in Italy. As in the USA, also in Italy the main terrain of the clash with Darwinism is the public school. The essay investigates the reasons why in Italy too has been possible to require to teach creationism alongside evolutionism. If in the US this is explained by the strong influence of the evangelical communities, in Italy creationism has found fertile ground in the traditional backwardness of the country in terms of scientific culture. To this we must add a relativistic epistemological interpretation that allows to equalize scientific doctrines to ideologies
Il rischio idrogeologico e la rete viaria nazionale minore
Il rischio definisce la possibilità che un fenomeno naturale o antropico possa causare effetti dannosi sulla popolazione, sugli insediamenti, sulle infrastrutture o in generale su quelli che vengono definiti elementi esposti.
Il concetto di rischio è legato non solo alla capacità di calcolare la probabilità che un evento pericoloso accada, ma anche alla capacità di definire e quantificarne il danno provocato. Il territorio nazionale italiano, data la sua conformazione orografica, geologica e geomorfologica caratterizzata da un???orografia giovane e da rilievi in sollevamento, è sempre stato interessato da fenomeni idraulici e geologici (fenomeno impropriamente chiamato, anche se ormai di uso corrente, (dissesto idrogeologico) di notevole intensità . Il caso di studio adottato fa riferimento alla Provincia di Lucca, data la particolare rilevanza di
fenomeni di dissesto idrogeologico in questa area
Design and synthesis of bis-amide and hydrazide-containing derivatives of malonic acid as potential HIV-1 integrase inhibitors
HIV-1 integrase (IN) is an attractive and validated target for the development of novel therapeutics against AIDS. In the search for new IN inhibitors, we designed and synthesized three series of bis-amide and hydrazide-containing derivatives of malonic acid. We performed a docking study to investigate the potential interactions of the title compounds with essential amino acids on the IN active site
Factors Impacting σ- and π-Hole Regions as Revealed by the Electrostatic Potential and Its Source Function Reconstruction: The Case of 4,4'-Bipyridine Derivatives
Positive electrostatic potential (V) values are often associated with σ- and π-holes, regions
of lower electron density which can interact with electron-rich sites to form noncovalent interactions.
Factors impacting σ- and π-holes may thus be monitored in terms of the shape and values of the
resulting V. Further precious insights into such factors are obtained through a rigorous decomposition
of the V values in atomic or atomic group contributions, a task here achieved by extending the
Bader–Gatti source function (SF) for the electron density to V. In this article, this general methodology
is applied to a series of 4,4'-bipyridine derivatives containing atoms from Groups VI (S, Se) and VII
(Cl, Br), and the pentafluorophenyl group acting as a π-hole. As these molecules are characterized
by a certain degree of conformational freedom due to the possibility of rotation around the two
C–Ch bonds, from two to four conformational motifs could be identified for each structure through
conformational search. On this basis, the impact of chemical and conformational features on σ- and
Ï€-hole regions could be systematically evaluated by computing the V values on electron density
isosurfaces (VS) and by comparing and dissecting in atomic/atomic group contributions the VS
maxima (VS,max) values calculated for different molecular patterns. The results of this study confirm
that both chemical and conformational features may seriously impact σ- and π-hole regions and
provide a clear analysis and a rationale of why and how this influence is realized. Hence, the proposed
methodology might offer precious clues for designing changes in the σ- and π-hole regions, aimed at
affecting their potential involvement in noncovalent interactions in a desired way
Comparative enantioseparation of planar chiral ferrocenes on polysaccharide-based chiral stationary phases.
Planar chiral ferrocenes are well-known compounds that have attracted interest for application in synthesis, catalysis, material science, and medicinal chemistry for several decades. In spite of the fact that asymmetric synthesis procedures for obtaining enantiomerically enriched ferrocenes are available, sometimes, the accessible enantiomeric excess of the chiral products is unsatisfactory. In such cases and for resolution of racemic planar chiral ferrocenes, enantioselective high-performance liquid chromatography (HPLC) on polysaccharide-based chiral stationary phases (CSPs) has been used in quite a few literature articles. However, although moderate/high enantioselectivities have been obtained for planar chiral ferrocenes bearing polar substituents, the enantioseparation of derivatives containing halogens, or exclusively alkyl groups, remains rather challenging. In this study, the enantioseparation of ten planar chiral 1,2- and 1,3-disubstituted ferrocenes was explored by using five polysaccharide-based CSPs under multimodal elution conditions. Baseline enantioseparations were achieved for nine analytes with separation factors (α) ranging from 1.20 to 2.92. The presence of π-extended systems in the analyte structure was shown to impact affinity of the most retained enantiomer toward amylose-based selectors, observing retention times higher than 80 min with methanol-containing mobile phases (MPs). Electrostatic potential (V) analysis and molecular dynamics (MD) simulations were used in order to study interaction modes at the molecular level
Analisi HPLC su Fase Stazionaria a Base Polisaccaridica: una Metodologia Innovativa ad Alta Sensibilità per l’Identificazione di Interazioni σ-hole Stereoselettive
Rational Design, Synthesis, Characterization and Evaluation of Iodinated 4,4′-Bipyridines as New Transthyretin Fibrillogenesis Inhibitors
The 3,30,5,50-tetrachloro-2-iodo-4,40-bipyridine structure is proposed as a novel chemical
scaold for the design of new transthyretin (TTR) fibrillogenesis inhibitors. In the frame
of a proof-of-principle exploration, four chiral 3,30,5,50-tetrachloro-2-iodo-20-substituted-4,40-
bipyridines were rationally designed and prepared from a simple trihalopyridine in three steps,
including a Cu-catalysed Finkelstein reaction to introduce iodine atoms on the heteroaromatic
scaold, and a Pd-catalysed coupling reaction to install the 20-substituent. The corresponding
racemates, along with other five chiral 4,40-bipyridines containing halogens as substituents, were
enantioseparated by high-performance liquid chromatography in order to obtain pure enantiomer
pairs. All stereoisomers were tested against the amyloid fibril formation (FF) of wild type (WT)-TTR
and two mutant variants, V30M and Y78F, in acid mediated aggregation experiments. Among
the 4,40-bipyridine derivatives, interesting inhibition activity was obtained for both enantiomers of
the 3,30,5,50-tetrachloro-20-(4-hydroxyphenyl)-2-iodo-4,40-bipyridine. In silico docking studies were
carried out in order to explore possible binding modes of the 4,40-bipyridine derivatives into the TTR.
The gained results point out the importance of the right combination of H-bond sites and the presence
of iodine as halogen-bond donor. Both experimental and theoretical evidences pave the way for the
utilization of the iodinated 4,40-bipyridine core as template to design new promising inhibitors of
TTR amyloidogenesis
Progettazione, Proprietà e Applicazione di Molecole σ-hole-attive in Soluzione: un Nuovo Strumento per la Chimica Sostenibile
Exploring interaction modes between polysaccharide-based selectors and biologically active 4,4′-bipyridines by experimental and computational analysis
In the last few years, chiral 4,4′-bipyridine derivatives have been developed for different applications in catalysis, enantioseparation science, supramolecular and theoretical chemistry by modulating the activity of the molecular system through the introduction of specific substituents in the heteroaromatic scaffold. More recently, the biological activity of 2′-substituted-3,3′,5,5′-tetrachloro-2-iodo-4,4′-bipyridines has been explored in the field of transthyretin (TTR) fibrillogenesis inhibition, and the anticancer cytotoxicity of some derivatives is currently under systematic investigation. In this frame, the high-performance liquid chromatography (HPLC) enantioseparation of four atropisomeric 2,2′-disubstituted-4,4′-bipyridines (R, R’ = Ar, I), which contain multiple interaction
sites, such as hydrogen bonding (HB) donors and acceptors, halogen bond (XB) donors, and -extended electronic clouds, was explored by using n-hexane (Hex)/2-propanol (2-PrOH) 90:10 v/v as a mobile phase (MP), and eight chiral columns with coated and immobilized amylose- and cellulose-based relectors. The impact of subtle structural variations of analytes and selectors on their mutual intermolecular interactivity was evaluated in terms of
retention (k) and selectivity () factors. On this basis, chromatographic analysis based on systematic screening of analytes and selectors was integrated with electrostatic potential (V) analysis and molecular dynamics (MD) simulations as computational techniques. The effect of temperature on retention, selectivity, and enantiomer elution order (EEO) of the analytes with coated and immobilized amylose tris(3,5-dimethylphenylcarbamate) was also
considered by comparing the variation of the thermodynamic profile associated with each enantioseparation. Chromatographic responses proved to be strictly dependent on specific regions within the analyte, and functions of different interactions sites of the analytes as the structure of the chiral selector changes were significantly disclosed
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