2,427 research outputs found

    OpenKnowledge at work: exploring centralized and decentralized information gathering in emergency contexts

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    Real-world experience teaches us that to manage emergencies, efficient crisis response coordination is crucial; ICT infrastructures are effective in supporting the people involved in such contexts, by supporting effective ways of interaction. They also should provide innovative means of communication and information management. At present, centralized architectures are mostly used for this purpose; however, alternative infrastructures based on the use of distributed information sources, are currently being explored, studied and analyzed. This paper aims at investigating the capability of a novel approach (developed within the European project OpenKnowledge1) to support centralized as well as decentralized architectures for information gathering. For this purpose we developed an agent-based e-Response simulation environment fully integrated with the OpenKnowledge infrastructure and through which existing emergency plans are modelled and simulated. Preliminary results show the OpenKnowledge capability of supporting the two afore-mentioned architectures and, under ideal assumptions, a comparable performance in both cases

    A novel mechanical analogy based battery model for SoC estimation using a multi-cell EKF

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    The future evolution of technological systems dedicated to improve energy efficiency will strongly depend on effective and reliable Energy Storage Systems, as key components for Smart Grids, microgrids and electric mobility. Besides possible improvements in chemical materials and cells design, the Battery Management System is the most important electronic device that improves the reliability of a battery pack. In fact, a precise State of Charge (SoC) estimation allows the energy flows controller to exploit better the full capacity of each cell. In this paper, we propose an alternative definition for the SoC, explaining the rationales by a mechanical analogy. We introduce a novel cell model, conceived as a series of three electric dipoles, together with a procedure for parameters estimation relying only on voltage measures and a given current profile. The three dipoles represent the quasi-stationary, the dynamics and the istantaneous components of voltage measures. An Extended Kalman Filer (EKF) is adopted as a nonlinear state estimator. Moreover, we propose a multi-cell EKF system based on a round-robin approach to allow the same processing block to keep track of many cells at the same time. Performance tests with a prototype battery pack composed by 18 A123 cells connected in series show encouraging results.Comment: 8 page, 12 figures, 1 tabl

    Luminal endothelialization of small caliber silk tubular graft for vascular constructs engineering

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    : The constantly increasing incidence of coronary artery disease worldwide makes necessary to set advanced therapies and tools such as tissue engineered vessel grafts (TEVGs) to surpass the autologous grafts [(i.e., mammary and internal thoracic arteries, saphenous vein (SV)] currently employed in coronary artery and vascular surgery. To this aim, in vitro cellularization of artificial tubular scaffolds still holds a good potential to overcome the unresolved problem of vessel conduits availability and the issues resulting from thrombosis, intima hyperplasia and matrix remodeling, occurring in autologous grafts especially with small caliber (<6 mm). The employment of silk-based tubular scaffolds has been proposed as a promising approach to engineer small caliber cellularized vascular constructs. The advantage of the silk material is the excellent manufacturability and the easiness of fiber deposition, mechanical properties, low immunogenicity and the extremely high in vivo biocompatibility. In the present work, we propose a method to optimize coverage of the luminal surface of silk electrospun tubular scaffold with endothelial cells. Our strategy is based on seeding endothelial cells (ECs) on the luminal surface of the scaffolds using a low-speed rolling. We show that this procedure allows the formation of a nearly complete EC monolayer suitable for flow-dependent studies and vascular maturation, as a step toward derivation of complete vascular constructs for transplantation and disease modeling

    Effect of annealing temperature on microstructure and high-temperature tensile behaviour of Ti-6242S alloy produced by Laser Powder Bed Fusion

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    This work is focussed at investigating the properties of additive manufactured Ti-6242S, a Ti alloy with excellent mechanical strength and stability up to 550 °C. Special attention is given to the effect of different heat treatment routes on microstructure and high-temperature mechanical behaviour of the Ti-6242S alloy produced by Laser Powder Bed Fusion. Annealing was performed in the α/β field (at 940 °C, 960 °C, 980 °C) or above the β transus (at 1050 °C). Annealing step was followed by Ar gas cooling and ageing at 595 °C. The as-built material exhibits high strength and anisotropic behaviour, showing lower fracture elongation in the direction parallel to the build platform. Heat treatments are responsible for a reduction of material strength but an increase in fracture elongation. Tensile tests at high temperature show that the best heat treatment for applications up to 300 °C is the annealing at 940 °C followed by Ar cooling and ageing. For applications at higher temperatures (namely 550 °C, 750 °C) the annealing step should be performed above the β transus temperature, at 1050 °C, to achieve the best tensile properties

    Enabling Information Gathering Patterns for Emergency Response with the OpenKnowledge System

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    Today's information systems must operate effectively within open and dynamic environments. This challenge becomes a necessity for crisis management systems. In emergency contexts, in fact, a large number of actors need to collaborate and coordinate in the disaster scenes by exchanging and reporting information with each other and with the people in the control room. In such open settings, coordination technologies play a crucial role in supporting mobile agents located in areas prone to sudden changes with adaptive and flexible interaction patterns. Research efforts in different areas are converging to devise suitable mechanisms for process coordination: specifically, current results on service-oriented computing and multi-agent systems are being integrated to enable dynamic interaction among autonomous components in large, open systems. This work focuses on the exploitation and evaluation of the OpenKnowledge framework to support different information-gathering patterns in emergency contexts. The OpenKnowledge (OK) system has been adopted to model and simulate possible emergency plans. The Lightweight Coordination Calculus (LCC) is used to specify interaction models, which are published, discovered and executed by the OK distributed infrastructure in order to simulate peer interactions. A simulation environment fully integrated with the OK system has been developed to: (1) evaluate whether such infrastructure is able to support different models of information-sharing, e.g., centralized and decentralized patterns of interaction; (2) investigate under which conditions the OK paradigm, exploited in its decentralized nature, can improve the performance of more conventional centralized approaches. Preliminary results show the capability of the OK system in supporting the two afore-mentioned patterns and, under ideal assumptions, a comparable performance in both cases

    Co3O4 Nanopetals on Si as Photoanodes for the Oxidation of Organics

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    Cobalt oxide nanopetals were grown on silicon electrodes by heat-treating metallic cobalt films deposited by DC magnetron sputtering. We show that cobalt oxide, with this peculiar nanostructure, is active towards the photo-electrochemical oxidation of water as well as of organic molecules, and that its electrochemical properties are directly linked to the structure of its surface. The formation of Co3O4 nanopetals, induced by oxidizing annealing at 300 \ub0C, considerably improves the performance of the material with respect to simple cobalt oxide films. Photocurrent measurements and electrochemical impedance are used to explain the behavior of the different structures and to highlight their potential application in water remediation technologies

    Inhibition of the hepatitis C virus NS3/4A protease. The crystal structures of two protease-inhibitor complexes.

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    The hepatitis C virus NS3 protein contains a serine protease domain with a chymotrypsin-like fold, which is a target for development of therapeutics. We report the crystal structures of this domain complexed with NS4A cofactor and with two potent, reversible covalent inhibitors spanning the P1–P4 residues. Both inhibitors bind in an extended backbone conformation, forming an anti-parallel β-sheet with one enzyme β-strand. The P1 residue contributes most to the binding energy, whereas P2–P4 side chains are partially solvent exposed. The structures do not show notable rearrangements of the active site upon inhibitor binding. These results are significant for the development of antivirals

    BBB-endothelial cell response to cerebral cortex demyelination in a mouse model of chronic EAE

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    Changes in blood-brain barrier (BBB) function have been implicated in demyelinating diseases. This study aimed to investigate the response of cerebral cortex microvessels to nerve fibre demyelination in a chronic model of murine experimental autoimmune encephalomyelitis (EAE) characterized by areas of extensive subpial demyelination along with well-demarcated lesions extended to deeper cortex layers. These cortices showed activation of microglia and astrogliosis with absence of typical perivascular inflammatory infiltrates. On the basis of these data, we have analyzed the expression of two integral proteins of endothelial tight junctions, claudin-5 and occludin, a structural protein of caveolae, caveolin-1, as well as the BBB-specific endothelial transporter, Glut1 in the cerebral cortex of EAE-affected mice by immunofluorescence confocal microscopy. Microvascular endothelial cells showed an increased expression of caveolin-1 and a coincident decrease of both claudin-5 and occludin junctional staining pattern. At a very early disease stage, claudin-5 molecules formed aggregates and vacuoles that also stained for Glut 1, whereas occludin pattern became diffusely cytoplasmic at advanced stages of the disease. Internalization/dismantling and loss of tight junction proteins and impairment of BBB function were confirmed by coexpression of claudin-5 whit the autophagosomal marker MAP1LC3A and by FITC-dextran experiments that showed leakage of the tracer into the perivascular neuropil. Overall, these observations indicate that in the cerebral cortex of EAE mice, during demyelination and independently from the inflammatory involvement of the cortex, a ‘microvascular disease’ characterized by a differential involvement of claudin-5 and occludin occurs, thereby possibly contributing to demyelinating disease progression
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