Stefania evansi

Number of Pages: 3Integrative BiologyGeological Science

Bone morphogenic protein antagonist Drm/gremlin is a novel proangiogenic factor.

15Angiogenesis plays a key role in various physiologic and pathologic conditions, including tumor growth. Drm/gremlin, a member the Dan family of bone morphogenic protein (BMP) antagonists, is commonly thought to affect different processes during growth, differentiation, and development by heterodimerizing various BMPs. Here, we identify Drm/gremlin as a novel proangiogenic factor expressed by endothelium. Indeed, Drm/gremlin was purified to homogeneity from the conditioned medium of transformed endothelial cells using an endothelial-cell sprouting assay to follow protein isolation. Accordingly, recombinant Drm/gremlin stimulates endothelial-cell migration and invasion in fibrin and collagen gels, binds with high affinity to various endothelial cell types, and triggers tyrosine phosphorylation of intracellular signaling proteins. Also, Drm/gremlin induces neovascularization in the chick embryo chorioallantoic membrane. BMP4 does not affect Drm/gremlin interaction with endothelium, and both molecules exert a proangiogenic activity in vitro and in vivo when administered alone or in combination. Finally, Drm/gremlin is produced by the stroma of human tumor xenografts in nude mice, and it is highly expressed in endothelial cells of human lung tumor vasculature when compared with non-neoplastic lung. Our observations point to a novel, previously unrecognized capacity of Drm/gremlin to interact directly with target endothelial cells and to modulate angiogenesis.openopenSTABILE H; S. MITOLA; MORONI E; BELLERI M; NICOLI S; COLTRINI D; PERI F; PESSI A; ORSATTI L; TALAMO F; CASTRONOVO V; WALTREGNY D; COTELLI F; RIBATTI D; PRESTA MStabile, H; Mitola, Stefania Maria Filomena; Moroni, Emanuela; Belleri, Mirella; Nicoli, Stefania; Coltrini, Daniela; Peri, F; Pessi, A; Orsatti, L; Talamo, F; Castronovo, V; Waltregny, D; Cotelli, F; Ribatti, D; Presta, Marc

The Community Structure of the Global Corporate Network

We investigate the community structure of the global ownership network of transnational corporations. We find a pronounced organization in communities that cannot be explained by randomness. Despite the global character of this network, communities reflect first of all the geographical location of firms, while the industrial sector plays only a marginal role. We also analyze the network in which the nodes are the communities and the links are obtained by aggregating the links among firms belonging to pairs of communities. We analyze the network centrality of the top 50 communities and we provide the first quantitative assessment of the financial sector role in connecting the global economy

Crystal dislocations with different orientations and collisions

We study a parabolic differential equation whose solution represents the atom dislocation in a crystal for a general type of Peierls-Nabarro model with possibly long range interactions and an external stress. Differently from the previous literature, we treat here the case in which such dislocation is not the superpositions of transitions all occurring with the same orientations (i.e. opposite orientations are allowed as well)

Finite element simulation of semi-finishing turning of Electron Beam Melted Ti6Al4V under dry and cryogenic cooling

open6noIn the last few years, important step forwards have been made on Finite Element Simulation of machining operations. Wrought Ti6Al4V alloy has been deeply investigated both numerically and experimentally due to its wide application in the industry. Recently, Additive Manufacturing technologies as the Electron Beam Melting and the Direct Melting Laser Sintering are more and more employed in the production of biomedical and aeronautical components made of Ti6Al4V alloy. Fine acicular microstructures are generated by the application of additive manufacturing technologies, affecting the mechanical properties and the machinability. By the consequence, this peculiarity has to be considered in modelling the material behaviour. In this work, a numerical analysis of cylindrical external turning on Electron Beam Melted (EBM) Ti6Al4V alloy is presented. A Johnson-Cook constitutive equation was implemented as a flow stress model and adapted with respect to the wrought Ti6Al4V alloy. The model was calibrated and validated through the cutting forces and temperatures measurements acquired under dry and cryogenic lubricating conditions.openBordin, A; Imbrogno, S.; Rotella, G.; Bruschi, S.; Ghiotti, A.; Umbrello, D.Bordin, Alberto; Imbrogno, S.; Rotella, G.; Bruschi, Stefania; Ghiotti, Andrea; Umbrello, D

Relaxation times for atom dislocations in crystals

We study the relaxation times for a parabolic differential equation whose solution represents the atom dislocation in a crystal. The equation that we consider comprises the classical Peierls-Nabarro model as a particular case, and it allows also long range interactions. It is known that the dislocation function of such a model has the tendency to concentrate at single points, which evolve in time according to the external stress and a singular, long range potential. Depending on the orientation of the dislocation function at these points, the potential may be either attractive or repulsive, hence collisions may occur in the latter case and, at the collision time, the dislocation function does not disappear. The goal of this paper is to provide accurate estimates on the relaxation times of the system after collision. More precisely, we take into account the case of two and three colliding points, and we show that, after a small transition time subsequent to the collision, the dislocation function relaxes exponentially fast to a steady state. We stress that the exponential decay is somehow exceptional in nonlocal problems (for instance, the spatial decay in this case is polynomial). The exponential time decay is due to the coupling (in a suitable space/time scale) between the evolution term and the potential induced by the periodicity of the crystal

Too big, will fail. Megaevents and protest participation

The paper examines the relationship between "social democratic megaevents" (Olympic Games and World Expos) and political protests. It tries to analyze the reasons that led these popular ceremonies to act in our societies as catalysts of social conflict and activators of an "agonistic citizenship". Today some structural characteristics of the network society - growth of urban populations; increase in migration flows; widening of socioeconomic disparities - determined a renewed "political" interest for these great public rituals, which in a previous season of the modernity had shown themselves capable to patch up the lacerations of the social fabric. But in recent years something is broken in the relationship between megaevents and urban populations and we are witnessing a growing antagonism against events historically conceived with a function of social "glue". The aim is therefore to reflect on the meaning of this "antagonistic drift" of "social democratic megaevents" through the analysis of a specific case study: the Attitudine NoExpo Network (Milan 2015). We identified four crucial dimensions to trace the NoExpo movement's physiognomy and define the reasons for its opposition to the world fair: the historical relation between Milan and a cultural form of antagonism; the crucial role of the territorial factor in the formation and evolution of the movement; the centrality of the practices in the structuring of the movement's identity; the adoption of an instrumental and tactical approach in the choice and use of media