1,721,054 research outputs found
"Synchrotron Radiation and Materials Science" symposium at the Spring Meeting of the European Materials Research Society, Strasbourg, May-June 2005.
No full textOver 120 abstracts were submitted to the symposium on Synchrotron Radiation and Materials Science. There were 10 invited speakers and 25 talks from scientist from European countries, the USA and Japan. Proceedings were published as a special volume of Nuclear Instruments and Methods B
MULTI-COMPONENT CATIONIC LIPOSOME/DNA COMPLEXES: NEW EFFICIENT VECTORS FOR GENE DELIVERY
No full textProceedings of European Materials Research Society 2005 -Symposium O - Strasbourg, France, May - June 2005: "Synchrotron Radiation and Materials Science"
No full textMulticomponent cationic lipid-DNA complex formation: Role of lipid mixing
No full textMulticomponent cationic lipid-DNA complexes (lipoplexes) were prepared by adding linear DNA to mixed lipid dispersions containing two populations of binary cationic liposomes and characterized by means of small angle X-ray scattering (SAXS). Four kinds of cationic liposomes were used. The first binary lipid mixture was made of the cationic lipid (3?[N-(N?,N?-dimethylaminoethane)-carbamoyl]cholesterol (DC-Chol) and the neutral helper lipid dioleoylphosphocholine (DOPC) (DC-Chol/DOPC liposomes), the second one of the cationic 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) and the neutral dio- leoylphosphatidylethanolamine (DOPE) (DOTAP/DOPE liposomes), the third one of DC-Chol and DOPE (DC-Chol/DOPE liposomes), and the fourth one of DOTAP and DOPC (DOTAP/DOPC liposomes). Upon DNA-induced fusion of liposomes, large lipid mixing at the molecular level occurs. As a result, highly organized mixed lipoplexes spontaneously form with membrane properties intermediate between those of starting liposomes. By varying the composition of lipid dispersions, different DNA packing density regimes can also be achieved. Furthermore, occurring lipid mixing was found to induce hexagonal to lamellar phase transition in DOTAP/DOPE membranes. Molecular mechanisms underlying experimental findings are discussed
Experimental analysis of catalyst degradation in High Temperature PEM Fuel Cells subjected to accelerated ageing tests
No full textThe loss in performance during fuel cell operation is one of the critical factors that hamper fuel cells commercialization. This paper presents the University of Trieste Engineering and Architecture department research activity related to High Temperature Polymer Electrode Membrane (HT-PEM) fuel cell degradation. The aim of the research is to correlate catalyst degradation with fuel cell operation mode and performance. For evaluating catalyst degradation, a procedure to analyze the Membrane Electrode Assembly (MEA) with Small Angle X-ray Scattering (SAXS) technique has been developed and presented. Furthermore, accelerated degradation test have been carried out for samples conditioning. Preliminary SAXS analysis results confirm the agglomeration of the Pt particles that leads to a growth in size from 5 nm up to 8 nm for the considered MEAs. Accelerated degradation tests show a fuel cell loss in performance lower than 6% after 100,000 load cycling. First SAXS results of these tests are presented
SAXS Analysis of Catalyst Degradation in High Temperature PEM Fuel Cells Subjected to Accelerated Ageing Tests
No full textThe loss in performance during fuel cell operation is one of the critical factors that hamper fuel cells commercialization. This paper presents a research activity related to high temperature polymer electrode membrane fuel cell (HT-PEMFC) degradation. The aim of the study is to investigate catalyst degradation of membrane electrode assemblies (MEAs) subjected to load cycles. Two HT-PEM MEAs have been subjected to accelerated ageing tests based on load cycling. The cycles profile has been chosen in order to enhance catalyst degradation. Both the tests show a fuel cell performance loss lower than 30mV after 100,000 cycles at 600mAcm–2. In order to analyze the catalyst evolution, synchrotron small angle X-ray scattering (SAXS) has been employed. The catalyst degradation of the two conditioned samples has been compared with the data obtained from a new MEA that has been used as reference sample. The SAXS results showed a mean size increase of the platinum nanoparticles up to the 100%
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
- …
