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Morbiducci U.,Polytechnic University of Turin | Gallo D.,Polytechnic University of Turin | Massai D.,Polytechnic University of Turin | Ponzini R.,Interuniversity Consortium | And 4 more authors.
Journal of Biomechanics | Year: 2011

Here we present a study on the impact of assumptions on image-based hemodynamic simulations of healthy carotid bifurcations. In particular, we evaluate to which extent assumptions on blood rheology influence bulk flow features, driven by the fact that few studies have provided adequate insights into the influence of assumptions to confidently model the 4D hemodynamics within the bifurcation. The final goal is to complement, integrate and extend with a quantitative characterization of the bulk flow the description currently adopted to classify altered hemodynamics, which is based on wall shear stress (WSS).Hemodynamic simulations of two image-based carotid bifurcation geometries were carried out assuming a reference Newtonian viscosity, two non-Newtonian rheology models and Newtonian viscosities based on characteristic shear rates. WSS-based and Lagrangian-based metrics for helical flow quantification and for vorticity dynamics quantification were calculated. Our findings suggest that the assumption of Newtonian rheology: (1) could be reasonable for bulk flow metrics (differences from non-Newtonian behavior are lower than 10%); (2) influences at different levels the WSS-based indicators, depending on the bifurcation model, even if in our study it is lower than the major source of uncertainty as recognized by the literature (i.e., uncertainty on geometry reconstruction). © 2011 Elsevier Ltd.

Guarnieri T.,University of Bologna | Guarnieri T.,S. Orsola Malpighi University Hospital | Guarnieri T.,Interuniversity Consortium
Current Cancer Drug Targets | Year: 2016

Epidemiological data suggest that Non Steroidal Anti Inflammatory Drugs (NSAIDs) and Cyclooxygenase 2 (COX2) inhibitors (COXibs) can exert chemopreventive and antitumour effects in many human neoplasia. This is particularly true in colon cancer (CC), where the regular assumption of these molecules has been shown to exert chemopreventive and chemotherapeutic effects. Since the late ‘90s, there has been a progressive increase in experimental evidence, indicating that in CC the antiproliferative effects of NSAIDs and COXibs could be both dependent on and independent of COXs inhibition, and that these effects do not necessarily exclude each other. This review will examine some of these COX-independent cellular pathways, with a focus on those involved in the inhibition of CC cells proliferation through transcription factors crosstalk. © 2016 Bentham Science Publishers.

Guarrasi M.,University of Palermo | Guarrasi M.,Interuniversity Consortium | Reale F.,University of Palermo | Reale F.,National institute for astrophysics | And 3 more authors.
Astronomy and Astrophysics | Year: 2014

Context. The expansion of coronal loops in the transition region may considerably influence the diagnostics of the plasma emission measure. The cross-sectional area of the loops is expected to depend on the temperature and pressure, and might be sensitive to the heating rate. Aims. The approach here is to study the area response to slow changes in the coronal heating rate, and check the current interpretation in terms of steady heating models. Methods. We study the area response with a time-dependent 2D magnetohydrodynamic (MHD) loop model, including the description of the expanding magnetic field, coronal heating and losses by thermal conduction, and radiation from optically thin plasma. We run a simulation for a loop 50 Mm long and quasi-statically heated to about 4 MK. Results. We find that the area can change substantially with the quasi-steady heating rate, e.g., by ~40% at 0.5 MK as the loop temperature varies between 1 MK and 4 MK, and, therefore, affects the interpretation of the differential emission measure vs. temperature (DEM(T)) curves. © 2014 ESO.

Bertazzo M.,Interuniversity Consortium | Di Iorio A.,University of Rome La Sapienza
Journal of Digital Information | Year: 2012

The article describes the integrated adoption of Fedora Commons and MediaMosa for managing a digital repository. The integration was experimented along with the development of a cooperative project, Sapienza Digital Library (SDL). The functionalities of the two applications were exploited to built a weaving factory, useful for archiving, preserving and disseminating of multi-format and multi-protocol audio video contents, in different fruition contexts. The integration was unleashed by means of both repository-to-repository interaction, and mapping of video Content Model's disseminators to MediaMosa's Restful services. The outcomes of this integration will lead to a more flexible management of the dissemination services, as well as to economize the overproduction of different dissemination formats.

Morbiducci U.,Polytechnic University of Turin | Ponzini R.,Interuniversity Consortium | Rizzo G.,CNR Institute of Molecular Bioimaging and Physiology | Cadioli M.,Philips | And 3 more authors.
Biomechanics and Modeling in Mechanobiology | Year: 2011

The hemodynamics within the aorta of five healthy humans were investigated to gain insight into the complex helical flow patterns that arise from the existence of asymmetries in the aortic region. The adopted approach is aimed at (1) overcoming the relative paucity of quantitative data regarding helical blood flow dynamics in the human aorta and (2) identifying common characteristics in physiological aortic flow topology, in terms of its helical content. Four-dimensional phase-contrast magnetic resonance imaging (4D PC MRI) was combined with algorithms for the calculation of advanced fluid dynamics in this study. These algorithms allowed us to obtain a 4D representation of intra-aortic flow fields and to quantify the aortic helical flow. For our purposes, helicity was used as a measure of the alignment of the velocity and the vorticity. There were two key findings of our study: (1) intra-individual analysis revealed a statistically significant difference in the helical content at different phases of systole and (2) group analysis suggested that aortic helical blood flow dynamics is an emerging behavior that is common to normal individuals. Our results also suggest that helical flow might be caused by natural optimization of fluid transport processes in the cardiovascular system, aimed at obtaining efficient perfusion. The approach here applied to assess in vivo helical blood flow could be the starting point to elucidate the role played by helicity in the generation and decay of rotating flows in the thoracic aorta. © 2010 Springer-Verlag.

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