PubMed | University Rome, University Roma, New York State Department of Health and New York University
Type: | Journal: Genetics | Year: 2017
The protein phosphatase 2A (PP2A) is a conserved heterotrimeric enzyme that regulates several cellular processes including the DNA damage response and mitosis. Consistent with these functions, PP2A is mutated in many types of cancer and acts as a tumor suppressor. In mammalian cells, PP2A inhibition results in DNA double strand breaks (DSBs) and chromosome aberrations (CABs). However, the mechanisms through which PP2A prevents DNA damage are still unclear. Here, we focus on the role of the Drosophila twins (tws) gene in the maintenance of chromosome integrity; tws encodes the B regulatory subunit (B/B55) of PP2A. Mutations in tws cause high frequencies of CABs (0.5 CABs/cell) in Drosophila larval brain cells and lead to an abnormal persistence of -H2Av repair foci. However, mutations that disrupt the PP4 phosphatase activity impair foci dissolution but do not cause CABs, suggesting that a delayed foci regression is not clastogenic. We also show that Tws is required for activation of the G2/M DNA damage checkpoint, while PP4 is required for checkpoint recovery, a result that points to a conserved function of these phosphatases from flies to humans. Mutations in the ATM-coding gene tefu are strictly epistatic to tws mutations for the CAB phenotype, suggesting that failure to dephosphorylate an ATM substrate(s) impairs DNA DSBs repair. In addition, mutations in the Ku70 gene, which do not cause CABs, completely suppress CAB formation in tws Ku70 double mutants. These results suggest the hypothesis that an improperly phosphorylated Ku70 protein can lead to DNA damage and CABs.
Siontas S.,National Technical University of Athens |
Kyritsakis A.,National Technical University of Athens |
Xanthakis J.P.,National Technical University of Athens |
Iacobucci S.,CNR Institute for Photonics and Nanotechnologies |
Stefani G.,University Roma
Journal of Vacuum Science and Technology B:Nanotechnology and Microelectronics | Year: 2014
The authors have calculated the lateral distribution of field emitted electrons from a carbon nanofiber (CNF) array - a quantity of importance in designing field emission displays - by calculating the electron distribution from an individual CNF and subsequently summing the contribution from all individual CNFs. The authors have not obtained the absolute value of the current but only its relative distribution in space. The full width at half maximum of the lateral distribution has been examined with respect to the following parameters: 1) the CNF tip radius, 2) the anode to cathode distance, and 3) the cathode to anode potential difference. Reasonable agreement with experimental results is obtained. © 2014 American Vacuum Society.
Rocca M.L.,University Roma |
Adduce C.,University Roma |
Lombardi V.,University Roma |
Sciortino G.,University Roma |
Hinkelmann R.,TU Berlin
International Journal for Numerical Methods in Fluids | Year: 2012
In this paper the dynamics of a two-layered liquid, made of two immiscible shallow-layers of different density, has been investigated within the framework of the lattice Boltzmann method (LBM). The LBM developed in this paper for the two-layered, shallow-water flow has been obtained considering two separate sets of LBM equations, one for each layer. The coupling terms between the two sets have been defined as external forces, acted on one layer by the other. Results obtained from the LBM developed in this paper are compared with numerical results obtained solving the two-layered, shallow-water equations, with experimental and other numerical results published in literature. The results are interesting. First, the numerical results obtained by the LBM and by the shallow-water model can be considered as equivalent. Second, the LBM developed in this paper is able to simulate motion conditions on nonflat topography. Third, the agreement between the LBM (and also shallow-water model) numerical results and the experimental results is good when the evolution of the flow does not depend on the viscosity, that is, during the initial phase of the flow, dominated by gravity and inertia forces. When the viscous forces dominate the evolution of the flow the agreement between numerical and experimental results depends strongly on the viscosity; it is good if the numerical LBM viscosity has the same order of magnitude of the liquid's kinematic viscosity. © 2012 John Wiley & Sons, Ltd.
La Rocca M.,University Roma |
Mele P.,University Roma |
Sciortino G.,University Roma |
Boniforti M.A.,University of Rome La Sapienza
Environmental Hydraulics: Theoretical, Experimental and Computational Solutions - Proceedings of the International Workshop on Environmental Hydraulics, IWEH 2009 | Year: 2010
In this paper a mathematical model for 3D turbidity currents has been presented. The model consists in a system of partial differential equations in conservative form, formulated in the framework of the shallow water equations and it accounts for the main features of the turbidity currents: entrainment of environment fluid, settling and resuspension of particles, variation of density. A numerical investigation has been performed to assess the influence of the settling of particles on the turbidity current. To this aim different turbidity currents have been simulated, with the same excess density and initial volume, but realized with silicon carbide particles with increasing diameter. Numerical results are compared with experimental results by La Rocca et al.. The agreement is fairly good and shows the ability of the proposed model in reproducing the main features of the physical phenomenon. © 2010 Taylor & Francis Group, London.
Limongelli C.,University Roma |
Sciarrone F.,OpenInformatica srl |
Sciarrone F.,University of Rome La Sapienza |
Temperini M.,OpenInformatica srl
Communications in Computer and Information Science | Year: 2013
Nowadays, thanks to the Internet, the request for distance learning is increasing. Private companies and public institutions are very sensitive to the saving of costs that such type of education could implicate, i.e., with no limits in time and place. Besides, the results obtained by this kind of learning are comparable to those reached by the classic in-presence lessons. Consequently, instructional designers need didactic instruments to build courses in a rapid way, especially if they would build their courses starting from learning objects already posted into Learning Object Repositories by other peers. Our work proposes a system, at a very early stage of development, with the aim to help instructional designers to find and retrieve learning objects suitable for their courses, starting from the classic conceptual map of the course to be built. The system contains an OLAP module to let teachers to drill-down into concepts as well. © Springer-Verlag Berlin Heidelberg 2013.
News Article | February 19, 2017
Pope Francis gestures as he talks during a meeting at the University Roma Tre in Rome, Italy February 17, 2017. REUTERS/Max Rossi ROME (Reuters) - Politicians should lower the volume of their debates and stop insulting each other, Pope Francis said on Friday, adding that leaders should be open to dialogue with perceived enemies or risk sowing the seeds of war. "Insulting has become normal," he said in a 45-minute-long improvised talk to university students in Rome. "We need to lower the volume a bit and we need to talk less and listen more." Francis, the son of Italian migrants to Argentina, also warned against anti-immigrant movements and urged that newcomers be treated "as human brothers and sisters". While the pope spoke mostly in general terms about the need for more dialogue in society as he answered questions from four students at the Roma Tre campus, he singled out politicians. "In the newspapers, we see this one insulting that one, that one says this about the other one," he said. "But in a society where the standards of politics has fallen so much - I am talking about world society - we lose the sense of building society, of social co-existence, and social co-existence is built on dialogue." He spoke of "political debates on television where even before one (candidate) finishes talking, he is interrupted." Francis did not single out any countries for criticism. Italian political talk shows are often shrill and last year's U.S. presidential debates between Donald Trump and Hillary Clinton were peppered with insults. In one debate last September, for example, Trump called Clinton a "nasty woman" and she accused him of having "engaged in racist behavior". Francis urged everyone to seek "the patience of dialogue". He added: "Wars start inside our hearts, when I am not able to open myself to others, to respect others, to talk to others, to dialogue with others, that is how wars begin." The pope also warned against anti-immigrant movements, which have grown in the United States and a number of European countries, including Italy. "Migrations are not a danger. They are a challenge for growth," he said, adding it was important to integrate immigrants into host countries so they keep their traditions while learning new ones in a process of mutual enrichment. He said immigrants should be welcomed "first of all as human brothers and sisters. They are men and women just like us."