199 research outputs found
Metamorphic evolution of the Saka Unit (Central Pontides, Northern Turkey): new implications for the Mesozoic convergence-related processes in the Intra-Pontide suture zone
No full textIn Northern Turkey, the Intra-Pontide suture (IPS) zone represents an east-west trending belt of deformed and/or metamorphic rocks bounded by the Istanbul-Zonguldak Terrane (IZ) to the north and the Sakarya Composite Terrane (SK) to the south (e.g. Göncüoğlu et al., 1997). Despite its importance for the geodynamics reconstructions of the Black Sea and Eastern Mediterranean areas during the Mesozoic, the IPS zone has been poorly investigated; only recently the role of its metamorphic units during the syn-collisional evolution was explored (Marroni et al., 2014; Frassi et al., 2016; 2017)
In order to provide new insights on the Mesozoic-Tertiary geodynamic reconstruction of the southern margin of the Laurasia, we present new data from the Saka Unit from the eastern portion of the IPS. Using a multidisciplinary approach that includes lithological, structural, metamorphic and petrographic investigations, we constrained the P-T-t path during the Mesozoic subduction and consequent exhumation and accretion to Laurasia. Following the determination of mesostructures, we analysed a series of samples of metabasite and metapelite. Mineral chemistry of phases at equilibrium in the pervasive S2 foliation was determined, and PT determinations were performed through pseudosection calculation of three samples. PT conditions are within the epidote-amphibolite facies, with pressures of 1.2 ± 0.15 GPa and Temperatures 600 ± 50 °C, thus higher than those determined previously, suggesting that S2 could be a composite foliation where a progressive evolution acquired during onset of exhumation was recorded. A comparison with the PT evolutions of the nearby Daday and Domuz-Dag units, shows that they record lower T at D2 at different ages, and that the pre-D2 conditions, when they are preserved, are different in the three units.
References
Frassi C., Göncüoğlu M.C., Marroni M., Pandolfi L., Ruffini L. Ellero A., Ottria G. & Sayit K. 2016. The Intra-Pontide Suture Zone in the Tosya-Kastamonu area, Northern Turkey. J. of Maps. 12, 211-219
Frassi, C, Marroni, M., Pandolfi, L., Göncüoğlu, M. C., Ellero, A., Ottria, G., Sayit, K., McDonald, C.S., Balestrieri, M.L. & Malasoma, A. 2018. Burial and exhumation history of the Daday Unit (Central Pontides, Turkey): implications for the closure of the Intra-Pontide oceanic basin. Geol. Mag., 155, 356-376.
Göncüoğlu, M. C., Marroni, M., Sayit, K., Tekin, U. K., Ottria, G., Pandolfi, L. & Ellero, A., 2012. The Ayli Dag ophiolite sequence (central-northern Turkey): A fragment of middle Jurassic oceanic lithosphere within the Intra-Pontide suture zone. Ofioliti, 37, 77–91.
Marroni, M., Frassi, C., Göncüoğlu, C. M., Di Vincenzo, G., Pandolfi, L., Rebay, G., Ellero, A. & Ottria, G. 2014. Late Jurassic amphibolite-facies metamorphism in the Intra-Pontide Suture Zone (Turkey): an eastward extension of the Vardar Ocean from the Balkans into Anatolia? J. Geol. Soc., 171, 605–608
Isopentenyladenosine analogues as potential antitumor agents : synthesis and structure-activity relationships
No full textN6-Isopentenyladenosine (1, iPA) is a member of the cytokinin family, plant hormones that regulate cell growth and differentiation. iPA is the only known cytokinin existing in animal cells in a free form, as a mononucleotide in cytoplasm, or bound to t-RNA. At present, the biological role and the mechanism of action of iPA in mammalians cells are not fully understood. It has been demonstrated that iPA is able to inhibit protein prenylation1 and competes for nucleoside transport.2 Spinola3 et al. have recently demonstrated that iPA exerts a potent in vitro anticancer activity on human epithelial cancer cell lines while it has a slight effect on tumour growth in rodents. This lack of in vivo activity could be related to the short plasma half-life of iPA, as it is well known for other nucleosides. With the aim of identifying compounds endowed with in vitro and in vivo antiproliferative activity, we have investigated structural modifications of iPA. Initially, we have synthesized a few acyclonucleosides that are characterized by the presence of an acyclic component, structurally resembling part of the ribose moiety in iPA. Proliferation, clonogenicity, and gene expression profile analysis were evaluated in human epithelial cancer cell lines derived from different tumours. The results showed that the iPA ribofuranosidic ring is pivotal for its biological activity.4 Starting from these results we have synthesized iPA analogues in which the hydroxyl group in 2′, 3′ and 5′ positions were replaced by a hydrogen group in order to verify the importance of each hydroxyl group of the furanosidic moiety for the activity of iPA. Then other analogues where the base adenine was substituted by inosine were synthesized (O-isopentenylinosine and its deoxy-derivatives). All compounds were in vitro tested using T24 cell line and the proliferation assay was carried out in the presence and absence of serum. No activity was found for the tested compounds, except 3′ deoxy-iPA, that was able to cause cell death of quiescent cultures. We have also synthesized iPA analogues in which the N6-position was differently substituted with the aim of verify the importance of the isopentenyl chain for the activity of the molecule. Preliminary results of in vitro assays using these compounds (T24 cell line, proliferation assay in presence and absence of serum) allowed us to select some compounds with cytotoxicity as high as iPA. With these molecules we have performed additional experiments in order to clarify the mechanism of action of iPA and its derivatives. We are now studying the synthesis of analogues of iPA in which the furanosidic moiety is replaced by a hydroxylated cyclopentane in order to obtain more stable compounds replacing the β-N-glycosidic bond (N-C-O) by a N-C-C bond to increase the resistance to enzymatic hydrolysis.
[1] Laezza C., Notarnicola M., Caruso M.G., Messa C., Macchia M., Bertini S., Minutolo F., Portella G., Fiorentino L., Stingo S., Bifulco M.; N6-isopentenyladenosine arrests tumor cell proliferation by inhibiting farnesyl diphosphate synthase and protein prenylation. The FASEB J. 2006, 20, 412.
[2] Hakala M.T., Slocum H.K., Gryko G.J.; N6-(Δ2-Isopentenyl)adenosine an inhibitor of cellular transport of uridine and cytidine. J.Cell Physiol. 1975, 86, 281.
[3] Spinola M., Colombo F., Falvella F.S., Dragani T.A.; N6-isopentenyladenosine: a potential therapeutic agent for a variety of epithelial cancers. Int. J. Cancer 2007, 120, 2744.
[4] Colombo F., Favella F.S., Tortoreto M., Pratesi G., Ciuffreda P., Ottria R., Santaniello E., Cicatiello L., Weisz A. & Dragani T.A.; Pharmacogenomics and analogues of the antitumor agent N6-isopentenyladenosine. Int. J. Cancer 2009, 124, 217
Superimposed brittle structures in the Late orogenic extension of the Alpi Apuane (Northern Apennine, Italy)
No full textL’oratore e il filosofo : interazioni secentesche tra diversi campi del sapere
No full textFamiano Strada (1572-1649) was a Jesuit historian and writer who played an essential role in the Counter-Reformation period. This paper examines the representation of the perfect orator in the first book of his Prolusiones academicae, published in 1617 by Giacomo Mascardi in Rome. My primary focus is on the relationship between rhetoric and philosophy because the author drew inspiration from the works of Plato and Aristotle. Moreover, this article aims to shed light on further topics of interest, for example the importance of memory for the orator, the relationship between memory and intelligence, and the knowledge of various cultural fields. It is worth pointing out the author’s knowledge of ancient sources, which include not only Plato and Aristotle, but also Latin literature, in particular Cicero and Quintilian
[Recensione a] G. Genovese, Su un non identificato ciclo di affreschi nel Mauriziano, il «Casino dell’Ariosto», in «Italianistica», 52/2, 2023
No full text[Recensione a] S. Pinto, La promozione delle arti negli Stati italiani : dall’età delle riforme all’Unità, a cura di G. Capitelli, Torino, Einaudi, 2022
No full textFault tectonics of the Tuscan Nappe in the eastern sector of the Apuan Alps (Italy)
No full textWe present the geological-structural map of the Tuscan Nappe exposed on the eastern border of the Apuan Alps metamorphic dome (Tuscany, Italy). The 1:6,500 scaled Main Map covers an area of about 10 km(2). It contains the first detailed overview of the fault tectonics affecting the Tuscan Nappe during the exhumation and uplift of the Tuscan Metamorphic Units. We documented a polyphase fault tectonics that initially produced low-angle extensional faults and later high-angle faults. The latter started within a transtensional tectonic regime that produced left-lateral strike-slip faults. Lately a pure extensional tensor, indicating a switch of the maximum compression sigma 1 axis from sub-horizontal to sub-vertical, produced faults with a dominant dip-slip component. In our reconstruction the lateral thickness variations documented in several formations of the Tuscan Nappe is mainly controlled by tectonics and not by stratigraphy, as previously suggested
Note illustrative del Foglio 196 "Cabella Ligure" della Carta Geologica d'Italia in scala 1:50.000,
No full textFoglio 196 "Cabella Ligure" della Carta Geologica d'Italia in scala 1:50.000,
No full textCarta Geologica d'Italia alla scala 1:50.00
Tacito alla sbarra : citazioni e giudizi critici nelle “Prolusiones academicae” di Famiano Strada
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