130,964 research outputs found
Albumin as promiscuous biocatalyst in organic chemistry
No full textAlbumin has emerged as biocatalyst since 1980 and the everlasting interest for this protein is proved by numerous papers. The use of albumin was initially confined in the field of asymmetric oxidations and reductions whereas more recently it has found a broader application to chemical reactions such as addition, condensations and eliminations. This review reports the main applications of albumin in organic synthesis appeared in the literature in the last decade
N-heterocyclic carbene catalysis as a tool for gaining access to the 3,4-dihydropyran-2-one skeleton
No full textAn overview of the progress made in the synthesis of 3,4-dihydropyran-2-ones since the development of NHC catalysis is reported. Two distinct classes of species - electrophilic alpha,beta-unsaturated acylazolium and nucleophilic azolium enol/enolate intermediates - can easily be produced from different substrates through the intermediacy of NHC catalysis. They enable the construction of the 3,4-dihydropyran-2-one skeleton, the core of natural and synthetic products with significant biological activities, through Michael additions, cycloadditions and rearrangements
Numerical investigation of the impact of speed reduction on propeller excitation
No full textA numerical investigation of the impact of the speed reduction achieved by pitch or propeller Revolutions Per Minute (RPM) variations on propeller performances is proposed. A test case is selected from the European Project AQUO, for which experimental data are available. Numerical self-propulsion analyses are carried out to assess the off-design propeller functioning conditions of the propeller. Results, in terms of self-propulsion points and predicted pressure pulses in the various conditions under investigation (design speed at design pitch, reduced speed at reduced pitch and at reduced RPM), are compared with the available experimental measurements. On the basis of the predicted pressure pulses and cavitation volumes, conclusions are drawn about the acoustic impact of different strategies for realizing off-design operative conditions and on the possibility of ranking them by numerical methods
Progetti per tre luoghi della città
No full textL’articolo presenta tre progetti di edifici pubblici per le città di Cesena, Vicenza e Bolzano. Sviluppati dal 2001 al 2004 in occasione di altrettanti concorsi di progettazione, questi progetti affrontano il tema generale della relazione tra contesto urbano consolidato e architettura contemporanea.
Il progetto per Cesena (2003) propone la trasformazione dell’odierna “smisurata” piazza della Libertà in un sistema articolato di spazi pubblici attraverso l’introduzione di un Museo archeologico. Il progetto per Vicenza (2001) ha l’obiettivo della trasformazione del convento di Santa Corona attraverso la realizzazione di un Museo naturalistico e archeologico. Il progetto per Bolzano (2004) prevede la costruzione, sul luogo attualmente occupato da due scuole costruite negli anni Trenta, di un Centro Bibliotecario per istituzioni di lingua italiana e tedesca alla scala della Provincia
La politica religiosa dei primi imperatori cristiani e gli edifici sacri della Siria-Palestina
No full textSulla base di un riesame della documentazione relativa all’area siro-palestinese e soprattutto fenicia, più ricca di altre sia sul piano letterario (Eusebio di Cesarea e Sozomeno) che archeologico-epigrafico, si valutano le posizioni dei diversi imperatori del IV secolo d. C., da Costantino in poi, di fronte alla sopravvivenza dei culti e dei templi pagani della regione e alla resistenza che molte delle popolazioni locali, nelle città e nelle campagne, opposero alla progressiva affermazione della fede cristiana
Recensione a D. Fehling, Die Quellenangabe bei Herodot. Studien zur Erzählkunst Herodots, Berlin 1971
No full text
Gamma-ray sky points to radial gradients in cosmic-ray transport
No full textThe standard approach to cosmic-ray (CR) propagation in the Galaxy is based on the assumption that local transport properties can be extrapolated to the whole CR confining volume. Such models tend to underestimate the γ-ray flux above a few GeV measured by the Fermi Large Area Telescope toward the inner Galactic plane. We consider here for the first time a phenomenological scenario allowing for both the rigidity scaling of the diffusion coefficient and the convective effects to be position dependent. We show that within this approach we can reproduce the observed γ-ray spectra at both low and mid Galactic latitudes - including the Galactic center - without spoiling any local CR observable
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