692 research outputs found

    Recommendation for future actions in research and developments

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    The Sustainable Chemistry Issue Team has been active within the OECD Environment Health and Safety Programme since 1998 and has held many meetings in Germany and in Italy. Although Italy has organized two meetings (Venice, 1998 and 2001) and has an excellent scientific and technological background in the field, the coordination among research, academy and industry, necessary to undertake actions among the leader countries of this area, has not yet been activated. At this end the University Ca’ Foscari of Venice, in collaboration with the Istituto Superiore di Sanità (ISS – Italian Institute for Health) that co-ordinates in Italy the OECD activities in the framework of the Environment, Health and Safety Programme, has organized this Workshop aimed to the establishment of the Italian network on green and sustainable chemistry. The connection with EU achievements and with the recently instituted OECD Green Growth Knowledge Platform has been highlighted. The first part of the Workshop has addressed European activities carried out in this field. OECD, EuCheMS, UNESCO have participated. The second part, organised in collaboration with pertinent Italian ministries, universities, public research institutes and industries has highlighted the different point of views inherent to the sustainable development and in particular the state of art of the green and sustainable chemistry in Italy in connection with its international perspectives

    Risk factors for graft failure after penetrating keratoplasty

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    The objective of our study was to define principal risk factors for graft failure in patients who underwent penetrating keratoplasty (PK).Retrospective data obtained from a cohort of 895 penetrating keratoplasties performed between 2001 and 2006 were analysed. Recipient related factors, graft characteristics, and surgical technique were assessed in a univariate analysis and with a multivariate proportional hazard model to detect principal risk factors for definitive graft failure.Multivariate analysis showed clear significance for diagnosis and number of previous grafts and border line significance for the oldest donor age group. Patients with keratoconus had the best 10-year survival estimate (95%), followed by endothelial and stromal dystrophies (both 55%), infectious leukomas (49%), trauma (33%) and chemical burns (14%). Primary PK grafts had a survival rate of 81%, second grafts of 33% and third or more grafts of 16%. Overall 10-year survival estimate based on univariate analysis was found to be 65%.In conclusion, we found that primary diagnosis and previous graft failures in the recipient are the most important risk factors of graft failure after a PK

    Acute leukemia in association with Langerhans cell histiocytosis

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    Langerhans cell histiocytosis (LCH) and malignancy occurring in the same individual is unusual and has generally been the subject of isolated case reports. To better define the occurrence of these events a registry of cases with synchronous or asynchronous LCH and malignancy was developed with the cooperation of the Histiocyte Society. In 1991 the Histiocyte Society surveyed its members requesting information on cases in which LCH was associated with malignancy. The questionnaire was mailed to all members of the society and specifically requested information on the clinical and laboratory features of the cases, disease evolution, and response to therapy. Retrospective reporting was allowed. With this initial data, an ongoing registry of LCH patients with associated malignancy was begun of such cases, including evolution and response to therapy. Twenty-seven patients were enrolled during the first year of the registry, of whom 4 patients had the association of LCH with a malignant lymphoma and 10 cases had an association of LCH with other types of solid tumor. The remaining 13 patients had the association of LCH with acute leukemia. In five cases, LCH was associated with acute lymphoblastic leukemia FAB L1 (ALL). In four cases the ALL preceded the LCH by 6 months to 1 year. In four of five patients the LCH was localized; in two instances the LCH was treated with chemotherapy. In all cases the leukemia was treated according to local standard ALL protocols and in one case autologous bone marrow transplantation (ABMT) was performed at relapse. Three patients are free of leukemia, one of whom has persistent localized LCH of the skin. Two patients died of the ALL, one of whom was free of the LCH at the time of death. In eight instances LCH was reported in association with acute myeloid leukemia (AML). Six of these patients had a generalized form of LCH. In seven the diagnosis of LCH preceded the diagnosis of leukemia by more than 2 years (median 4 years). In the remaining patient both diagnoses were made concurrently. In all seven cases in whom LCH was the initial diagnosis the treatment consisted of chemotherapy and/or radiotherapy. Seven patients died from the AML, five without evidence of LCH. The temporal patterns of the LCH-ALL and LCH-AML associations are distinct with ALL usually preceding the diagnosis of LCH and AML succeeding it. Such a pattern is suggestive that in cases of ALL the LCH may be a reactive process while in cases of AML occurring after LCH the primary LCH therapy may play an inductive role in the leukemia. © 1994 Wiley-Liss, Inc

    Recognition of Intentional Violations of Active Constraints in Cooperative Manipulation Tasks

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    Active Constraints (ACs) are high-level control algorithms deployed to assist a human operator in man-machine cooperative tasks [1], and define regions within which it is safe for the robot to move and cut [2]. To enhance the performance in cooperative surgical tasks, adaptive constraints have been exploited to optimally adjust the provided level of assistance according to some knowledge of the task, hardware or user. In [3] Hidden Markov Models were used for the run-time detection of the user intention to leave a guidance constraint to circumvent an obstacle. In this work, we present a novel, Neural Network (NN)-based method for the runtime classification of intentional and unintentional violations of ACs, that is trained on either statistical or frequency features from the enforced constraint forces. We investigate which set of parameters yield faster and more reliable classification results, both for guidance and regional constraints

    Nafion-TiO2 composite DMFC membranes: Physico-chemical properties of the filier versus electrochemical performance

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    TiO2 nanometric powders were prepared via a sol-gel procedure and calcined at various temperatures to obtain different surface and bulk properties. The calcined powders were used as fillers in composite Nafion membranes for application in high temperature direct methanol fuel cells (DMFCs). The powder physico-chemical properties were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and pH measurements. The observed characteristics were correlated to the DMFC electrochemical behaviour. Analysis of the high temperature conductivity and DMFC performance reveals a significant influence of the surface characteristics of the ceramic oxide, such as oxygen functional groups and surface area, on the membrane electrochemical behaviour. A maximum DMFC power density of 350 mW cm-2 was achieved under oxygen feed at 145°C in a pressurized DMFC (2.5 bar, anode and cathode) equipped with TiO2 nano-particles based composite membranes. © 2004 Elsevier Ltd. All rights reserved

    Influence of TiO2 nanometric filler on the behaviour of a composite membrane for applications in direct methanol fuel cells

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    Composite Nafion membranes containing various amounts of TiO2 (3 wt%, 5 wt% and 10 wt%) were investigated for operation in high temperature Direct Methanol Fuel Cells (DMFCs). Maximum power density of 350 mW cm -2 was achieved in the presence of oxygen feed at 145°C for the composite membranes containing 3-5 wt% TiO2; whereas, the maximum power density with air feed was about 210 mW cm-2. Moreover, an investigation of the influence of titanium oxide particle size on the electrochemical behaviour of the composite membranes for high temperature operation has been carried out. The DMFC performance increases as the mean particle size of the TiO2 filler decreases. This indicates an influence of the filler morphology on the electrochemical properties of the composite membranes. © J. New. Mat. Electrochem. Systems

    Synthesis, Characterization and Electrocatalytic Activity of Bi- and Tri-metallic Pt-Based Anode Catalysts for Direct Ethanol Fuel Cells

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    Three Pt-based anode catalysts supported on Vulcan XC-72R (VC) were prepared by using a modified polyol process. These materials were characterized and tested by X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF) and Transmission Electron Microscopy (TEM). XRD and TEM analysis indicated that especially the ternary anode catalysts consisted of uniform nanosized particles with sharp distribution. The Pt lattice parameter was smaller, in the ternary PtSnIr catalyst whereas it increased with the addition of Sn and Rh, in the corresponding binary and ternary catalysts. Cyclic voltammetry (CV) measurements showed that Sn, Ir and Rh may act as promoter of Pt enhancing ethanol electro-oxidation activity. It was found that the direct ethanol fuel cell (DEFC) performances were significantly improved with these modified anode catalysts. This effect on the DEFC performance is attributed to the so-called bi-tri-functional mechanism and to the electronic interaction between Pt and additives. The performance increased significantly with the temperature. However, it was also possible to observe some decay with time for all catalysts due to the formation of surface poisons, probably consisting in CO-like species. At 60 °C, the PtSnIr catalyst showed the best performance, as a result of a proper morphology and promoting effectFil: D'Urso, C.. Centro Nazionale della Ricerca. ITAE; ItaliaFil: Bonesi, Alejandro Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de La Plata; ArgentinaFil: Triaca, Walter Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de La Plata; ArgentinaFil: Castro Luna Berenguer, Ana Maria del Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de La Plata; ArgentinaFil: Baglio, V.. Centro Nazionale della Ricerca. ITAE; Italia; ItaliaFil: Aricò, A. S.. Centro Nazionale della Ricerca. ITAE; Italia; Itali

    Investigation of a Pt–Fe/C catalyst for oxygen reduction reaction in direct ethanol fuel cells

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    Three cathode catalysts (60% Pt/C, 30% Pt/C and 60% Pt–Fe/C), with a particle size of about 2–3 nm, were prepared to investigate the effect of ethanol cross-over on cathode surfaces. All samples were studied in terms of structure and morphology by using X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses. Their electrocatalytic behavior in terms of oxygen reduction reaction (ORR) was investigated and compared using a rotating disk electrode (RDE). The tolerance of cathode catalysts in the presence of ethanol was evaluated. The Pt–Fe/C catalyst showed both higher ORR activity and tolerance to ethanol cross-over than Pt/C catalysts. Moreover, the more promising catalysts were tested in 5 cm2 DEFC single cells at 60 and 80 °C. An improvement in single cell performance was observed in the presence of the Pt–Fe catalyst, due to an enhancement in the oxygen reduction kinetics. The maximum power density was 53 mW cm−2 at 2 bar rel. cathode pressure and 80 °C.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada
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