Cenni al modello del Big Bang, inflazione e materia oscura

Il presente lavoro intende offrire una panoramica sulla cosmologia osservativa seguendo il filo rosso della materia oscura e dell'inflazione: partendo da un'introduzione che discute criticamente l'importanza delle curve di rotazione nella rilevazione di materia oscura -ingrediente fondamentale per gli attuali modelli cosmologici-, si passa ad una rassegna delle principali fasi evolutive dell'universo secondo il modello del Big Bang. Sulla base di queste opportune premesse teoriche, nel terzo capitolo si esplora infine il ruolo della CMB nel panorama cosmologico recente: la teoria che ne spiega le anisotropie costituisce infatti un caso di studio interessante che non solo getta nuova luce sulle fasi del Big Bang, ma fornisce ulteriori evidenze per la presenza di materia oscura nell'universo

Lipid profile of Xylella fastidiosa Subsp. pauca associated with the olive quick decline syndrome

Lipids, components of the plasma and intracellular membranes as well as of droplets, provide different biological functions related to energy, carbon storage, and stress responses. Bacterial species display diverse membrane composition that changes in response to the different environmental conditions. During plant-pathogen interactions, lipids might have roles in several aspects such as recognition, signal transduction, and downstream responses. Among lipid entities, free fatty acids (FFAs) and their oxidized form, the oxylipins, represent an important class of signaling molecules in host-pathogen perception, especially related to virulence and defense. In bacteria, FFAs (e.g., diffusible signaling factors) and oxylipins have a crucial role in modulating motility, biofilm formation, and virulence. In this study, we explore by LC-TOF and LC-MS/MS the lipid composition of Xylella fastidiosa subsp. pauca strain De Donno in pure culture; some specific lipids (e.g., ornithine lipids and the oxylipin 7,10-diHOME), characteristic of other pathogenic bacteria, were revealed. Nicotiana tabacum was used for testing the ability of this pathogen in producing such lipids in the host. Different lipid compounds present a clear distribution pattern within the infected plant tissues compared to the uninfected ones

Energy Efficient Non-Cooperative Methods for Resource Allocation in Cognitive Radio Networks

In a cognitive radio network wherein primary and secondary users coexist, an efficient power allocation method repre-sents one of the most important key aspects. This paper provides a novel approach based on a game theory framework to solve this problem in a distributed and fair way. Formulated as an optimization problem, the resource allocation prob-lem between secondary users and primary users can be modeled and investigated with the Game Theory, and in par-ticular S-Modular Games, since they provide useful tools for the definition of multi objective distributed algorithms in the context of radio communications. This paper provides also a performance comparison among the proposed game and two other algorithms, frequently used in this context: Simulated Annealing and Water Filling

SEISMOLOGICAL ANALYSIS OF THE 1917 MONTERCHI EARTHQUAKE (CENTRAL APENNINES, ITALY) FOR SEISMOTECTONIC IMPLICATIONS

On April 26, 1917 at 9:35:59 (GMT) an earthquake occurred in the Sansepolcro Basin (the northernmost portion of the High Tiber Valley - Italy) producing large damages and fatalities. This event, noted as Monterchi earthquake, is well constrained in the Catalogue of Strong Italian Earthquakes (Boschi et al., 2000) by 134 felt reports locations, mainly distributed on the right side of the Tiber Valley, mostly affecting the towns of Monterchi, Citerna and surrounding localities. The maximum and epicentral intensity was determined as Io=IX-X degree of the MCS scale corresponding to an equivalent magnitude of Me=6 that define this event as the most important of the region. The Sansepolcro Basin was generated on the hanging-wall of the Altotiberina Fault (ATF) system. The ATF system is composed by an E-dipping low-angle normal fault, active at least since the Late Pliocene, that represents one of the main regional detachments of the Northern Apennines, and its antithetic W-dipping high-angle normal faults (Barchi, et al., 2009, Boncio et al., 2000). Although the southern part of the ATF was demonstrated to creep (Piccinini et al., 2003), its capability to generate strong or moderate earthquakes is still debated and the historical seismicity that affected the region was not associated to specific geologic sources. For these reasons the study of the Monterchi earthquake plays an important role in the debate. On this light, many authors tried to define the main seismic source parameters through the analysis of historical seismograms and respective bulletins. Preliminary results were presented at previous ECEES, ESC and EGU congresses (Caciagli et al., 2006, Ciaccio et al., 2008, Bernardi et al., 2009). In all these works the hypocentre of the Monterchi earthquake has been substantially unresolved, because of the absolute P and S-phases use, and, for this reason, its epicentre was located 20 km North of the macroseismic one. Concerning the focal mechanism, Bernardi et al. (2009) proposed a moment tensor solution for the Monterchi event, based on almost horizontal recordings from 4 stations situated in a very small azimuthal range. Independently of the validity of the normal fault mechanism proposed by Bernardi et al (2009) their conclusions fit perfectly in the context of the seismotectonic setting of the ATF, but do not account for the discrepancy between the instrumental and the macroseismic epicentres. Today, 49 seismograms from 19 different Euro-Mediterranean observatories are available in the database of the SISMOS Project – INGV (http://sismos.rm.ingv.it/) The BAAS (British Association for Advancement of Sciences) bulletin of 1917, although if incomplete because of the 1st World War, reports a list of 21 seismological observatories that recorded the P and S-phases for this earthquake. Additionally to this database, we included additional arrival-times deriving from further seismic bulletins not contained in the BAAS reports and from directly digitizing original historical seismograms. An incisive approach to analyse these different data allows us to obtain a new, robust and consistent hypocentral solution, coherent with the macroseismic data, in particular by using S-P travel time differences for recordings where the absolute timing is uncertain. An accurate research on the technical characteristics of the recording historical seismometers (period, damping, gain etc), including the analysis of the instrumental natural period recorded in some seismograms, allows to deconvolute the original digitized seismic traces in order to evaluate the potential of moment tensor inversion, to determine the main seismic parameters (Mo, Mw, Circular Fault Radius), and to implement the solution in the framework of the regional tectonic setting

Hybrid Magnetic Nanovectors Promote Selective Glioblastoma Cell Death through a Combined Effect of Lysosomal Membrane Permeabilization and Chemotherapy

Glioblastoma multiforme is the most aggressive brain tumor, due to its high invasiveness and genetic heterogeneity. Moreover, the blood-brain barrier prevents many drugs from reaching a therapeutic concentration at the tumor site, and most of the chemotherapeutics lack in specificity toward cancer cells, accumulating in both healthy and diseased tissues, with severe side effects. Here, we present in vitro investigations on lipid-based nanovectors encapsulating a drug, nutlin-3a, and superparamagnetic iron oxide nanoparticles, to combine the proapoptotic action of the drug and the hyperthermia mediated by superparamagnetic iron oxide nanoparticles stimulated with an alternating magnetic field. The nanovectors are functionalized with the peptide angiopep-2 to induce receptor-mediated transcytosis through the blood-brain barrier and to target a receptor overexpressed by glioma cells. The glioblastoma multiforme targeting efficiency and the blood-brain barrier crossing abilities were tested through in vitro fluidic models, where different human cell lines were placed to mimic the tumor microenvironment. These nanovectors successfully cross the blood-brain barrier model, maintaining their targeting abilities for glioblastoma multiforme with minimal interaction with healthy cells. Moreover, we showed that nanovector-assisted hyperthermia induces a lysosomal membrane permeabilization that not only initiates a caspase-dependent apoptotic pathway, but also enhances the anticancer efficacy of the drug