117,966 research outputs found
Cap. 5 - I dipinti murali della Basilica di Porto
No full textLo studio della decorazione pittorica della Basilica di Porto si basa sulla ricognizione e mappatura capillare di tutte le superfici murarie rivenute nel corso degli scavi condotti tra il 1991 e il 2007 e sull'analisi e ricomposizione dei frammenti di intonaco dipinto trovati nella fossa 708. Sono state riconosciute e isolate cinque differenti campagne decorative succedutesi tra il V e il XII secolo
Tra pittura e parete. Palinsesti, riusi e obliterazioni nella diaconia di Santa Maria in via Lata tra VI e XI secolo
No full textSono stati scelti come osservatorio privilegiato per indagare il rapporto tra parete e pittura nel Medioevo (VI-XI secolo) gli ambienti sotterranei dell’antica diaconia di Santa Maria in via Lata. Essi rappresentano con la loro decorazione pittorica stratificata, ma in gran parte decontestualizzata poiché staccata negli anni Sessanta ed esposta dal 2000 al Museo Nazionale Romano Crypta Balbi, un caso emblematico di pareti dipinte intessute di palinsesti, riusi e obliterazioni, oggi fruibili solo grazie alle restituzioni 3D
A precipitation-based regionalization for Western Iran and regional drought variability
No full textThe spatial distribution of the seasonal and annual precipitation was analyzed in western Iran using data from 140 stations covering the period 1965–2000. Applying the Precipitation Concentration Index (PCI), the intra-annual precipitation variability was also studied. Furthermore, nine precipitation-derived parameters were used to regionalize climate in western Iran using principal component analysis and clustering techniques. Results suggest that five spatially homogenous sub-regions can be identified characterized by different precipitation regimes. The spatial pattern of seasonal precipitation seems to be highly controlled by the wide latitudinal extent of the region and by the pronounced orographic relieves, and the time of occurrence of the maximum precipitation varies from spring in the north to winter in the south. <br><br> The time variability of dry and wet periods in the identified sub-regions was analyzed using the Precipitation Index (PI) and the existence of any long-term trend was tested. Results show that the northern and southern regions of western Iran are characterized by different climatic variability. Furthermore, a negative long-term linear trend in the north and a weak positive trend in the south of the study area have been detected though they are not statistically significant
"Gli arredi liturgici medievali nella Puglia centro-settentrionale: una messa a punto ed alcune riflessioni per un crocevia tra culture"
No full textThe paper intends to propose brief reflections on some critical still open questions , which concern the works created by the sculptor David for the episcopal basilica of Siponto and by the workshop of the archdeacon Acceptus for the same ecclesiastical building, as well as for the church-grotto of San Michele in Monte Sant'Angelo, for the cathedral of Canosa and probably also for the episcopal seat of Bari. The considerations presented arise from a comparative look at the material evidence preserved at the cited sites and are offered to the discussion with a character of still preliminary fine-tuning, referring for further in-depth analysis to the subsequent research of the author
In vivo binding and hierarchy of assembly of the yeast RNA polymerase I transcription factors
No full textTranscription by RNA polymerase I in Saccharomyces cerevisiae requires a series of transcription factors that have been genetically and biochemically identified. In particular, the core factor (CF) and the upstream activation factor (UAF) have been shown in vitro to bind the core element and the upstream promoter element, respectively. We have analyzed in vivo the DNAse I footprinting of the 35S promoter in wild-type and mutant strains lacking one specific transcription factor at the time. In this way we were able to unambiguously attribute the protections by the CF and the UAF to their respective putative binding sites. In addition, we have found that in vivo a binding hierarchy exists, the UAF being necessary for CF binding. Because the CF footprinting is lost in mutants lacking a functional RNA polymerase I, we also conclude that the final step of preinitiation-complex assembly affects binding of the CF, stabilizing its contact with DNA. Thus, in vivo, the CF is recruited to the core element by the UAF and stabilized on DNA by the presence of a functional RNA polymerase I
Confronto fra capre di razza Tibetana e derivate dall'incrocio Tibetana x Maltese. II. Influenza dell'elettrostimolazione su alcune caratteristiche mioreologiche
No full textE' stato studiato l'effetto dell’elettrostimolazione della mezzena sulle caratteristiche reologiche di 6 muscoli di 10 capre di razza Tibetana e di 10 derivate dall'incrocio Tibetana x Maltese, raggruppate in classi di età (4-5, 5-6 e 7-8 anni). I risultati piú importanti possono essere cosí sintetizzati:
(a) il tipo genetico influenza il valore della coesione e della resilienza elastica: nella Tibetana la prima è piú bassa (6 per cento) e la seconda piú elevata (3 per cento);
(b) l'età alla mattazione è un fattore importante per adesione e masticabilità;
(c) l'elettrostimolazione non influenza le caratteristiche reologiche della carne;
(d) fra i muscoli presi in esame, il Semitendinosus è risultato il piú duro, quello che richiede il maggior lavoro di masticazione e che ha il piú elevato potere di ritenzione dell'acqua; viceversa il Rectus femoris per le prime due caratteristiche e il Semimembranosus per la terza
The CeCl3 Lewis Acid Promoter in the Stereoselective Construction of Carbon-Carbon Double Bonds
No full textThe presence of a C-C double bond in polyfunctionalized organic molecules is a crucial requirement
for the control of its biologically activity.(1) The importance of having a site in the molecule that is
able to generate geometrical isomerization of a carbon-carbon double bond stimulated the
development of new olefination methodologies. In particular, some efforts focused on the ability of
Lewis acids to provide a cheap alternative for the synthesis of molecules with C-C double bond in a
highly stereoselective fashion.
For several years, we have been investigating CeCl3 promoted organic reactions. This Lewis acid has
been found to efficiently promote carbon-carbon (2) and carbon-heteroatom bond formation
reactions.(3) In addition to being green in nature (4), CeCl3 has been widely used for both inter- and
intramolecular reactions for the synthesis of organic molecules with significant biological
importance.
Regarding the total synthesis of biologically active small molecules containing a carbon-carbon
double bond, we saw the possibility to employ CeCl3 in the stereoselective construction of 2,3-
dihydropyridones 1,(5) and 1,2-dihydroquinolines 2.(6)
The additional advantage of using CeCl3 in a reaction includes its selectivity and tolerance in the
presence of other functional groups. For instance, it can be used during the functionalization of
molecules at late stage involving complex molecules or undesirable use of protecting groups.
Introduction of C-C double bonds, which are known to increase the activity in macrolides against
bacterial RNA polymerase, is currently in progress in our laboratory.
References: 1. Shen, X.; Nguyen, T. T.; Koh, M. J.; Xu, D.; Speed, A. W.; Schrock, R. R.; Hoveyda, A. H. Nature 2017,
541, 380-385. 2. Bartoli, G.; Marcolin, M.; Sambri, L.; Marcantoni, E. Chem. Rev. 2010, 110, 6104-6143. 3. Properzi, R.
Marcantoni, E. Chem. Soc. Rev. 2014, 43, 779-791. 4. Cimarelli, C.; Di Nicola, M.; Diomedi, S.; Giovannini, R.;
Hanprecht, D.; Properzi, R.; Sorana, F.; Marcantoni, E. Org. Biomol. Chem. 2015, 13, 11687-11695. 5. Bordi, S.;
Cimarelli, C.; Lupidi, G.; Marsili, L.; Piermattei, P.; Marcantoni, E. J. Org. Chem. 2017, in preparation. 6. Cimarelli, C.;
Bordi, S.; Piermattei, P.; Pellei, M.; Del Bello, F.; Marcantoni, E. Tetrahedron 2017, submitted
17. Bifore
No full textScheda di catalogo su due transenne di finestra erratiche, conservate presso il convento domenicano di Santa Sabina a Roma e provenienti dalla chiesa del complesso monumentale
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