130,872 research outputs found
Polidoro da Caravaggio (1499 ca.-1543)
No full textNell'ambito degli artisti siciliani, o attivi in Sicilia, citati da Giorgio Vasari ne "Le vite de più eccellenti, pittori, scultori et architettori", il testo analizza la biografia e l'attività a Messina dell'architetto e pittore Polidoro da Caravaggio nel primo Cinquecento
L'ictus cerebrale.Epidemiologia,fattori di rischio e prevenzione
No full textL'ictus cerebrale è un evento di natura cerebro-vascolare improvviso ed inaspettato che determina la comparsa d un deficit neurologico. Gli esiti dell'ictus cerebrale, differenti in relazione all'importanza dell'evento, causano una riduzione delle funzioni motorie ed una qualità della vita modificata. La pratica motoria quotidiana, l'adozione di stili di vita fisicamente attivi, svolgono un importante ruolo preventivo dei fattori di rischio. Nell'articolo si presenta un percorso didattico di attività motorie adattate, al fine di favorire il ri-apprendimento degli schemi motori ed il recupero delle capacità motorie
Diversified upgrading of HMF via acetylation, aldol condensation, carboxymethylation, vinylation and reductive amination reactions
No full textMultiple sustainable methodologies were developed for the chemical upgrading of HMF: i) at 30–90 °C, highly selective base-catalyzed acetylation and carboxymethylation reactions of HMF with nontoxic reagents as isopropenyl acetate (iPAc) and dimethyl carbonate (DMC) were achieved to prepare the corresponding ester and carbonate products, (5-formylfuran-2-yl)methyl acetate (5-formylfuran-2-yl) methyl carbonate, respectively; ii) based on the combined use of iPAc/DMC with acetone, a tandem protocol of acetylation/transcarbonation and aldol condensation was designed to synthesize a variety of HMF-derived α,β-unsaturated carbonyl compounds; iii) in water as a solvent, a chemoselective Pd-catalysed reductive amination of HMF with amino-alcohols also including glycerol derivatives, was developed using H2 at atmospheric pressure; iv) finally, both HMF and its ester and carbonate products successfully underwent Wittig vinylation reactions promoted by a methyl carbonate phosphonium salt ( [Ph3PCH3] [CH3OCO2]), to obtain the corresponding olefins. The vinylation reagent (the salt) was a DMC derivative. In all cases i-iv), not only processes occurred under mild conditions, but post-reaction procedures (work-up and purification) were optimized to isolate final products in high yields of 85–98%
Microwave-assisted catalytic transfer hydrogenolysis of lignin-derived aromatic ethers over Ru/C
No full textCleavage of aromatic ether bonds through hydrogenolysis is one of the most promising routes for depolymerisation and transformation of lignin into value-added chemicals. Herein, we investigate the catalytic transfer hydrogenolysis (CTH) of benzyl phenyl ether (BPE), as a model molecule of alpha-O-4 lignin linkages, over commercial Ru/C under microwave irradiation using 2-propanol as H-donor. By tuning the reaction parameters, such as time, temperature and catalyst amount, BPE was fully converted, at 150 degrees C in 5 min of irradiation, with a related aromatics selectivity of 92%. Phenylethylphenyl ether (PPE), and diphenyl ether (DPE), as a models of beta-O-4 and 4-O-5 linkages, respectively, were also considered to this scope and under optimized reaction conditions, >99% and 72% conversion, respectively, were achieved with >89% aromatics selectivity. Remarkably, catalytic tests with moderate conversions clearly showed that the cleavage of etheric C-O bond was the primary step under CTH conditions, while the hydrogenations of the aromatic rings take place in a subsequent step. Overall, the screening of the reaction parameters was crucial to avoid the hydrogenation of aromatic rings. No less significant was the Ru/C stability, which has been recycled at least six times without any noticeable activity loss
Lo scavo dei via dei Piatti 10-11. Revisione dei rinvenimenti archeologici
No full textIn the area of via dei Piatti 10 – 11 in Milan, conspicuous archaeological remains were found at the beginning of the 1960s, including two remnants of imposing masonry structures, A (the eastern one) and B (the western one), still partially preserved. These are two parallel walls, dated for their construction technique around the 1st century A.D.,
preserved for 30 m in length, but damaged at both ends. Only the foundations and some leftovers of the high remain.
The archive documentation also recalls other poorly known structures (C, D and E) that have been destroyed soon after
their discovery. To the east of the structure A, traces of a pavement were preserved at the time of the excavation, while to the west of B was found a portion of a Roman-era road. During the archaeological investigations, several findings were also recovered, including a bronze applique depicting Virtus or Rome, dated to the 1st century A.D. and referable to the decoration of a sculptural group depicting a triumphal chariot. Therefore, it is possible to date the construction of the monumental complex hosting these elements to the first decades of the imperial era. Few other finds, such as mosaic portions and a pottery pipe, can be considered instead the leftovers of the previous buildings that were torn down on that occasion
Il tema della maschera fogliata nell’architettura severiana del Nord Italia: forme e contenuti di un’occasione di celebrazione del potere imperiale
No full textThe theme of the leafy mask (Blattmaske) is widely attested in the decorations of Roman imperial architectures, mainly in the first decades of the III century A. D. In can be found, in particular, in some Severan monuments of the capital, as the Arch of Septimius Severus in the Roman Forum, the Arch of the Argentarii and the Baths of Caracalla. All these buildings had a very important ideological value, celebrating the imperial family and their accomplishments through the images here exhibited. In this way, the Romans created a communication between the clients and the observers. The leafy masks were part of this, alluding to the wealth and prosperity created by the Severan emperors. They were used with the same meaning in the decorations of some important public monuments in the fora of Milan and Aquileia, where intensive construction work was undertaken during the Severan period. Therefore, it’s possible to identify in these cities of Northern Italy the use of Blattmasken as a tool to celebrate the imperial power in public crowded places, according to the models of the capital. The Severan emperors probably needed this strategy to consolidate their leadership in the Roman state
Metal‐Free Carbonaceous Catalytic Materials: Biomass Feedstocks for a Greener Future
No full textMetal-free catalytic systems (MFCS) have emerged as sustainable and cost-efficient heterogeneous catalysts, particularly in the case of carbonaceous materials with oxygen, nitrogen, boron, sulfur or phosphorus functionalities. This contribution aims to provide a general overview of the recent advances on the design of such materials, with emphasis on those derived from biomass waste and on the relationship between their structure and their activity. The opportunities of using MFCS in different areas of catalysis, including thermo-, electro-, and photo-catalysis, will be addressed for applications towards the upgrading of renewable feedstocks. This analysis will describe sustainable approaches not only with respect to the nature of catalyst but also for the employment of non-toxic and sustainable precursors, and for the efficiency of the synthetic protocol and its carbon footprint
Intrinsic Hölder spaces for fractional kinetic operators
No full textWe introduce anisotropic Hölder spaces that are useful for studying the regularity theory for non-local kinetic operators. The Hölder spaces are defined in terms of an anisotropic distance relevant to the Galilean geometric structure on R × R^d × R^d, with respect to which the operators considered are invariant. We prove an intrinsic Taylor-like formula, whose remainder is bounded in terms of the anisotropic distance of the Galilean structure. Our achievements naturally extend analogous known results for purely differential operators on Lie groups
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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