48 research outputs found

    Electrospun PHEA-PLA/PCL Scaffold for Vascular Regeneration: A Preliminary in\ua0Vivo Evaluation

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    Background. There is increasing interest in the development of vessel substitutes, and many studies are currently focusing on the development of biodegradable scaffolds capable of fostering vascular regeneration. We tested a new biocompatible and biodegradable material with mechanical properties similar to those of blood vessels. Methods. The material used comprises a mixture of a,b-poly(N-2-hydroxyethyl)-D,L-aspartamide (PHEA) and polylactic acid (PLA), combined with polycaprolactone (PCL) by means of electrospinning technique. Low-molecular-weight heparin was also linked to the copolymer. A tubular PHEA-PLA/PCL sample was used to create an arteriovenous fistula in a pig model with the use of the external iliac vessels. The flow was assessed by means of Doppler ultrasound examination weekly, and 1 month after the implantation we removed the scaffold for histopathologic evaluation. Results. The implants showed a perfect leak-proof seal and adequate elastic tension to blood pressure. About w3 weeks after the implantation, Doppler examination revealed thrombosis of the graft, so we proceeded to its removal. Histologic examination showed chronic inflammation, with the presence of foreign body cells and marked neovascularization. The material had been largely absorbed, leaving some isolated spot residues. Conclusions. The biocompatibility of PHEA-PLA/PCL and its physical properties make it suitable for the replacement of vessels. In the future, the possibility of functionalizing the material with a variety of molecules, to modulate the inflammatory and coagulative responses, will allow obtaining devices suitable for the replacement of native vessels

    NEMO: A Project for a km3^3 Underwater Detector for Astrophysical Neutrinos in the Mediterranean Sea

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    The status of the project is described: the activity on long term characterization of water optical and oceanographic parameters at the Capo Passero site candidate for the Mediterranean km3^3 neutrino telescope; the feasibility study; the physics performances and underwater technology for the km3^3; the activity on NEMO Phase 1, a technological demonstrator that has been deployed at 2000 m depth 25 km offshore Catania; the realization of an underwater infrastructure at 3500 m depth at the candidate site (NEMO Phase 2).Comment: Proceeding of ISCRA 2006, Erice 20-27 June 200

    The ANTARES Optical Beacon System

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    ANTARES is a neutrino telescope being deployed in the Mediterranean Sea. It consists of a three dimensional array of photomultiplier tubes that can detect the Cherenkov light induced by charged particles produced in the interactions of neutrinos with the surrounding medium. High angular resolution can be achieved, in particular when a muon is produced, provided that the Cherenkov photons are detected with sufficient timing precision. Considerations of the intrinsic time uncertainties stemming from the transit time spread in the photomultiplier tubes and the mechanism of transmission of light in sea water lead to the conclusion that a relative time accuracy of the order of 0.5 ns is desirable. Accordingly, different time calibration systems have been developed for the ANTARES telescope. In this article, a system based on Optical Beacons, a set of external and well-controlled pulsed light sources located throughout the detector, is described. This calibration system takes into account the optical properties of sea water, which is used as the detection volume of the ANTARES telescope. The design, tests, construction and first results of the two types of beacons, LED and laser-based, are presented.Comment: 21 pages, 18 figures, submitted to Nucl. Instr. and Meth. Phys. Res.

    Status of NEMO

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    The activities towards the realization of a km3 Cherenkov neutrino detector carried out by the NEMO Collaboration are described. Long-term exploration of a 3500 m deep-sea site close to the Sicilian coast has shown that it is optimal for the installation of the detector. The realization of a Phase-1 project, which is under way, will validate the proposed technologies for the realization of the km3 detector on a Test Site at 2000 m depth. The realization of a new infrastructure on the candidate site (Phase-2 project) will provide the possibility to test detector components at 3500 m depth

    First results of the Instrumentation Line for the deep-sea ANTARES neutrino telescope

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    In 2005, the ANTARES Collaboration deployed and operated at a depth of 2500 m a so-called Mini Instrumentation Line equipped with Optical Modules (MILOM) at the ANTARES site. The various data acquired during the continuous operation from April to December 2005 of the MILOM confirm the satisfactory performance of the Optical Modules, their front-end electronics and readout system. as well as the calibration devices of the detector. The in situ measurement of the Optical Module time response yields a resolution better than 0.5 ns. The performance of the acoustic positioning system, which enables the spatial reconstruction of the ANTARES detector with a precision of about 10 cm, is verified. These results demonstrate that with the full ANTARES neutrino telescope the design angular resolution of better than 0.3 degrees can be realistically achieved

    Sensitivity of an underwater Cerenkov km3 telescope to TeV neutrinos from Galactic Microquasars

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    In this paper are presented the results of Monte Carlo simulations on the capability of the proposed NEMO-km3^3 telescope to detect TeV muon neutrinos from Galactic microquasars. For each known microquasar we compute the number of detectable events, together with the atmospheric neutrino and muon background events. We also discuss the detector sensitivity to neutrino fluxes expected from known microquasars, optimizing the event selection also to reject the background; the number of events surviving the event selection are given. The best candidates are the steady microquasars SS433 and GX339-4 for which we estimate a sensitivity of about 5⋅10−115\cdot10^{-11} erg/cm2^2 s; the predicted fluxes are expected to be well above this sensitivity. For bursting microquasars the most interesting candidates are Cygnus X-3, GRO J1655-40 and XTE J1118+480: their analyses are more complicated because of the stochastic nature of the bursts.Comment: 20 pages, 3 figures, accepted by Astroparticle Physic

    The data acquisition system for the ANTARES neutrino telescope

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    The ANTARES neutrino telescope is being constructed in the Mediterranean Sea. It consists of a large three-dimensional array of photo-multiplier tubes. The data acquisition system of the detector takes care of the digitisation of the photo-multiplier tube signals, data transport, data filtering, and data storage. The detector is operated using a control program interfaced with all elements. The design and the implementation of the data acquisition system are described.Comment: 20 pages, 6 figures, accepted for publication in Nucl. Instrum. Meth.

    ANTARES: the first undersea neutrino telescope

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    The ANTARES Neutrino Telescope was completed in May 2008 and is the first operational Neutrino Telescope in the Mediterranean Sea. The main purpose of the detector is to perform neutrino astronomy and the apparatus also offers facilities for marine and Earth sciences. This paper describes the design, the construction and the installation of the telescope in the deep sea, offshore from Toulon in France. An illustration of the detector performance is given

    ESPON Italian evidence in changing Europe

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    Il volume, che rientra nelle attivitĂ  dell’ESPON Contact Point Italia, accoglie i risultati del contributo dei Partner Italiani allo sviluppo dei progetti del Programma ESPON 2013, acronimo di European Observation Network for Territorial Development and Cohesion. I testi sintetizzano ed evidenziano, tra l’altro, le relazioni con le politiche di sviluppo regionale dell’Italia, inserendole in un quadro di cooperazione transnazionale che coinvolge 28 + 4 paesi dell’Unione europea. Affrontando aspetti della politica territoriale europea che spaziano dall’innovazione e conoscenza all’accessibilitĂ , dal policentrismo alle aree metropolitane, dalla migrazione alla globalizzazione, gli Autori mettono in luce la posizione dell’Italia e delle regioni anche rispetto agli obiettivi fissati da Europe 2020. Uno spazio Ăš dedicato alle esperienze regionali che hanno trovato in ESPON uno stimolo e un’occasione di confronto; come pure ai concetti che sottendono il lessico, i principi di orientamento e i nuovi modelli della pianificazione in Europa; e alle esperienze formative rivolte alle giovani generazioni e ai decision maker Il libro si inquadra nelle iniziative del Semestre di Presidenza Italiana dell’Unione europea ed Ăš cofinanziato dal Ministero delle Infrastrutture e dei Trasporti (MIT) responsabile nazionale del Programma ESPON. E’ rivolto ai ricercatori, agli utilizzatori istituzionali, ai policy maker, ai “practioner” e ai “non specialisti”, tra cui gli studenti, affinchĂ© possano fare propri i risultati dell’impegno costante, rigoroso e rispettoso delle diversitĂ  territoriali che hanno contraddistinto, dal 2007 ad oggi, il contributo della ricerca, anche sperimentale e applicata, alla crescita della societĂ  italiana come parte integrante del sistema europeo. L’Osservatorio ESPON, per chi ancora non lo conosce, puĂČ rappresentare un viaggio nel territorio europeo, nelle sue diversitĂ  territoriali, economiche, sociali, culturali da integrare e rendere coese, sostenibili, mantenendo e sviluppando potenziali di competitivitĂ  crescenti e, nel contempo, innovando e diffondendo nuovi modi, metodologie, strumenti e prassi per fare del territorio un bene comune e condiviso. Dati, riferimenti e raccomandazioni politiche utili alla crescita del Paese completano il quadro. Presentazione del Ministro delle Infrastrutture, On. Maurizio Lupi Postfazione del Direttore della Coordination Unit del Programma ESPON, Peter MehlbyeThe book is part of the activities of ESPON Contact Point Italy. It includes the results of the contribution of the Italian partners in the development of projects under the ESPON 2013 Programme, which stands for European Observation Network for Territorial Development and Cohesion. The texts summarise and highlight, among other things, the relations with the regional development policies of Italy, placing them in a framework of transnational cooperation involving the 28 + 4 EU Countries. Addressing aspects of European territorial policy, ranging from innovation and knowledge accessibility, from the polycentrism to metropolitan areas, from migration to globalization, the authors highlight the position of Italy and of regions also in relation to the objectives set by Europe 2020. A place is devoted to the regional experiences that in the ESPON found a stimulus and an opportunity for discussion, as well as to the concepts behind the vocabulary, to the principles of guidance, and new planning models in Europe, and to the training experiences aimed at the younger generations and the decision makers The book forms part of the initiatives of the Italian Presidency of the European Union and is co-financed by the Ministry of Infrastructure and Transportation (MIT) in charge of the national ESPON Programme. It is aimed at researchers, institutional users, policy makers, at "practitioners" and "non-specialists" including students, so that they can make use of the results of the constant and rigorous work also respectful of the territorial diversities that have characterized the experimental and applied research since 2007, so contributing to the growth of Italian society as an integral part of the European system. The ESPON Monitoring Centre, for those who still do not know, can be a journey into the European territory, its territorial, economic, social, cultural diversities to integrate and make cohesive and sustainable, by maintaining and developing the increasing potentials of competitiveness and, at the same time, by innovating and disseminating new ways, methodologies, tools and practices to make the territory a common and shared good. Data, references and useful policy recommendations to the growth of the country are also included in the book. Presentation by the Minister of Infrastructure, Mr. Maurizio Lupi Afterword by the Director of the Coordination Unit ESPON Programme , Peter Mehlby
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