170,264 research outputs found
On the use of the PTFE method for panel flutter optimization
No full textA numerical approach for structural analysis based on the concept of parameter transfer finite elements (P-TFE) was proposed by the authors in previous papers Barboni R, Castellani A, Mannini A. Un metodo analitico-numerico per l'analisi strutturale. Atti del Dipartimento Aerospaziale, Roma, Novembre, 1988; Barboni R, Gaudenzi P, Mannini A, Santini P. An application to the dynamics of large space structures of a new semi-analytic method for structural analysis. 17th Congress ICAS, Stockholm, September, 1990; Barboni R, Gaudenzi P, Mannini A. Parameter-transfer finite element method for structural analysis. AIAA Journal 1993; 31:923-9; Barboni R, Mannini A, Scarponi C. Structural optimization with parameter-transfer finite element. Meccania 1995; 30: 291-304. Such elements are able to take into account, like a transfer function, the whole behaviour of the structure under concern, subject to dynamic, aerodynamic or thermal actions, and to produce, in analogy with the finite element method, a numerical technique of discretization of a continuum
Effect of Estradiol and Progesterone on ovine Amniotic Epithelial Cells
No full textThis study was designed to clarify Estradiol (E2) and Progesterone (P4) steroid effects on ovine Amniotic Epithelial
Cells (oAECs) that has a conserved plasticity and highly self-renewable capacity (Parolini et al., Stem Cells, 26(2),
300–311, 2008; Barboni et al., Stem Cell Rev Rep, 10:725–741, 2014). Based on their conserved
immunomodulatory properties, oAECs are suitable for allo and xeno-transplantation (Barboni et al., Cell Transplant,
21(11), 2377–2395, 2012; Muttini et al., Res Vet Sci, 94(1),158–169, 2013). To date, no information is present on
the effects of prolonged steroid exposition on AECs. oAECs were cultured as previously reported (Barboni et al.,
Cell Transplant. 21(11), 2377–2395, 2012) and treated with 12.5μM and 25μM of E2 or P4 (Sigma-Aldrich, Milan,
Italy), alone and in both combinations, for three passages. Untreated cells were marked control (CTR). At 70%
confluency, cells were detached for doubling time (DT) evaluation. Cells at fourth passage were differentiated for 21
days in osteogenic media (DM) (Mattioli et al., Cell Biol Int 36(1):7-19, 2012) without steroid. Alizarin Red and
Alcian-Blue (Sigma-Aldrich, Milano, Italy) stainings were performed. RNA and cDNA were obtained as previously
reported (Barboni et al., Cell Transplant. 21(11), 2377–2395, 2012). Real Time for NANOG, SOX2 ,OCT4 stemness
genes expression were performed by SensiFast SYBR (Bioline, Aurogene, Rome, Italy) using specific primers
(Mattioli et al., Cell Biol Int. 36(1):7-19, 2012).The protocol was: 5 min at 95°C, 30 cycles at 95°C for 15 sec, 60°C
for 30 sec, 72°C for 15 sec. Comparative Ct 2-ΔΔC(t) normalization to GAPDH was applied. IHC analyses were
carried out for Cytokeratin 8 and αSMA expression as previously reported (Barboni et al. PLoS ONE 7(2): e30974,
2012). Data expressed as mean (±SD), compared by one-way ANOVA followed by Tukey’s test (GraphPad Prism
5). Significant values for P < 0.05. Steroids treated ovine AECs proliferate with significant differences between
concentrations. While P4 treated cells showed cuboidal shape and Cytokeratin expression until third passage, CTR
and E2 treated cells showed a rapid downregulation of Cytokeratin and increased αSMA expression. oAECs with
E2+P4 showed both cell type morphology. Steroids modified stemness genes based on the concentration. 12.5 μM
E2, 25μM P4 and 25μM of both E2+P4 treatments maintained higher OCT4, NANOG and SOX2 expressions in
treated cells despite their progressive downregulation in the CTR. Moreover, compared to CTR, after Alizarin
staining, steroid pretreated cells suffered morphological changes under DM acquiring Alcian Blue-positive
chondrogenic-like morphology. AECs stemness properties and plasticity can be modified by prolonged steroidal
treatment. These data improve our knowledge, opening new prospective on oAEC use in stem cell-based therapy.
Acknowledgments. Research supported by H2020-MSCA ITN EJD-REP BIOTECH 675526
Gli 1,3-Dinitroalcani Come Immediati Precursori di Sistemi Aromatici
No full textI nitroalcani primari e secondari hanno da tempo dimostrato di essere una delle classi di composti più convenienti nella generazione di carbanioni stabilizzati e, quindi, nella formazione di nuovi legami C,C, semplici e doppi.1,2 Inoltre, la capacità della funzionalità nitro di poter contemporaneamente agire da forte gruppo elettron-attrattore e da ottimo gruppo uscente3 ha permesso, nel recente passato, di poter arrivare alla sintesi “one pot” di sistemi aromatici a partire da nitroalcani (Schema 1).
Continuando nello studio dell’applicazione dei nitroderivati nella sintesi di sistemi benzenici, abbiamo ora trovato che attraverso gli 1,3-dinitroalcani è possibile ottenere una serie di benzeni polialchilati e polifunzionalizzati, molto difficili da ottenere per altra via (Schema 2).
Risultati e condizioni di reazione verranno riportati.
1 G, Rosini In Comprehensive Organic Synthesis; B. M. Trost, Ed.; Pergamon: Oxford, 1991, Vol. 2, p. 321.
2 R. Ballini, G. Bosica, D. Fiorini, A. Palmieri, M. Petrini Chem. Rev. 2005, 105, 933.
3 R. Ballini, A. Rinaldi Tetrahedron Lett. 1994, 35, 9247.
4 (a) R. Ballini, L. Barboni, G. Bosica J. Org. Chem. 2000, 65, 6261. (b) R. Ballini, L. Barboni, G. Giarlo, D. Fiorini, A. Palmieri Chem. Commun. In press
Does your neighbour know you better? Local banks and credit tightening in the financial crisis
No full textThis paper is a study about local banks in Italy, with a special focus on the role these financial intermediaries have played before and during the crisis in lending to firms. Although in the literature there is not a clear consensus on the link between local banks and access to credit, our paper shows that the firms predominantly funded by local banks have been less rationed during the crisis. This result holds when we consider also the firm characteristics, the shape of the bank-firm relationship, and the features of the local credit market where the firm is located. This result supports the view that local banks may address firms' financial needs in a better way than not local banks because of their comparative advantage at collecting local information. This advantage appears to be relevant in a period of high risk aversion
El proyecto multilingüe: Español-inglés-francés
No full textFil: Barboni, Silvana. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.Fil: Ghirimoldi, María Eugenia. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina
Unprecedented two-step synthesis of symmetrical diarylamines from 2-alkyl-1,3-dinitropropanes
No full textThis letter reports a new, two-step synthesis of symmetrical diarylamincs from 1,3-dinitroproparics, by their reaction with acrolein under basic conditions (Al2O3, neat), followed by aromatisation of the obtained 2,4-dinitrocyclohexanols, through their treatment with four equivalents of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), in acetonitrile as a solvent. and warming overnight at 60 degrees C. (c) 2006 Elsevier Ltd. All rights reserve
T-lymphocyte subpopulations at high altitudes. Morococha, Peru - 4560 meters above sea-level.
No full textA class of C° finite elements for the static and dynamic analysis of laminated plates
No full textA general higher-order deformation theory is developed to analyse the behaviour of an arbitrary laminated fibre-reinforced composite plate. Three-dimensional effects such as the warping of sections and the presence of interlaminar stress field components are taken into account assuming a power series expansion of displacements along the thickness. A class of C0 finite element models based on this theory is then developed for mono- and bi-dimensional elements. Applications of the models to bending and vibration of laminated plates are then discussed. The present solutions are compared with those obtained using the three-dimensional elasticity theory, classical laminate theory and other higher-order theories
Ca(2+_)independent protein kinase C signalling in mouse eggs during the early phases of fertilization
No full textProtein kinase C (PKC), an enzyme playing a central role in signal transduction pathways, is activated in fertilized mouse eggs downstream of the fertilization Ca2+ signal, to regulate different aspects of egg activation. Given the presence of Ca2+-independent PKC isoforms within the egg, we investigated whether fertilization triggers PKC stimulation in mouse eggs by activating Ca2+-independent signalling pathways. An increase in PKC activity was detected as early as 10 min after the beginning of insemination, when about 90% of eggs had fused with sperm and the first Ca2+ rise was evident in most of the eggs. A similar level of activity was found 20 min later, when about 60% of eggs had resumed meiosis. When the Ca2+ increase was buffered by an intracellular Ca2+ chelating agent, PKC stimulation was not blocked but only slightly reduced. Confocal microscopy analysis revealed that the increase in PKC activity at fertilization coincided with the translocation of PKCdelta, a Ca2+-independent and diacylglycerol-dependent PKC isoform, to the meiotic spindle. When, in the absence of the Ca2+ signal, meta phase-anaphase transition was inhibited, PKCdelta moved to the meiotic spindle but still maintained a sustained cytoplasmic distribution. In summary, our results indicate that: 1) PKC activation is an early event of egg activation; 2) both Ca2+-dependent and Ca2+-independent pathways contribute to increased PKC activity at fertilization; 3) PKCdelta is one of the isoforms participating in this signalling process.[...
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