1,720,977 research outputs found
Oxide/hydroxide films on tin. II: Characterization of the anodic growth in alkaline solutions
Full text linkThe anodic growth of oxide/hydroxide films formed on tin in borate solutions (pH 8.9) has been studied. At potentials more positive than -0.2 V (SHE), oxide film growth occurs by an activation-controlled ionic condition under the influence of a high electric field across the film according to an exponential law as on valve metals. Optical properties of the anodic oxide films have been obtained by "in situ" ellipsometry. Tin oxide/hydroxide films are practically transparent and highly hydrated. Electrical properties of tin oxide layers have been obtained by electrochemical impedance spectroscopy. Impedance spectra are explained in terms of a simple physical model assuming that oxide layer behaves as an inhomogeneous single-layer film.Fil: Brunetti, Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Lopez Teijelo, Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentin
The importance of Dendrimers in the Pharmaceutical Uses
No full textThe development of molecular nanostructures with well-defi ned particle shapes and sizes, such as dendrimers and dendritic structures, are of great importance. New nanomaterials could be prepared using these structures as building blocks. Unique properties of dendritic macromolecules make them much more useful for biomedical and pharmaceutical applications than linear polymers. Therefore, over the last three decades, dendrimers have found a special place in polymer-based pharmaceutical technology. This chapter describes the general characteristics of dendrimers, synthetic methodologies and their properties. Finally, some characteristic examples of dendrimers used in the fields of pharmaceutical science and nanomedicine are presented. Since successful applications of dendrimers and dendritic structures are feasible on a small scale, a promising future can be seen for their use in these fi elds.Fil: Brunetti, Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Martinelli, Marisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Strumia, Miriam Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin
Oxide/hydroxide films on tin. Part I: Kinetic aspects of the electroformation and electroreduction of the films
Full text linkThe anodic behaviour of tin in borate solutions has been studied by linear potential sweep voltammetry and triangularly modulated triangular potential sweeps. It is shown that the active to passive transition involves the formation of intermediate soluble species followed by the precipitation of a tin oxide/hydroxide layer that passivates the electrode. The potentiodynamic current-potential behaviour is adequately described by using the Layer-pore-resistance model. A good agreement between experimental and theoretical curves is obtained which allow us to demonstrate that primary passivation of tin in alkaline borate solutions (pH 8.9) as well as the film electroreduction is mainly controlled by the resistance of the electrolyte in the pores of the layer. In addition, the triangularly modulated triangular potential sweep method is applied in order to analyze the existence of reaction intermediates.Layer-pore-resistance model. A good agreement between experimental and theoretical curves is obtained which allow us to demonstrate that primary passivation of tin in alkaline borate solutions (pH 8.9) as well as the film electroreduction is mainly controlled by the resistance of the electrolyte in the pores of the layer. In addition, the triangularly modulated triangular potential sweep method is applied in order to analyze the existence of reaction intermediates.Fil: Brunetti, Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Lopez Teijelo, Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentin
Nanoparticle-cored dendrimers: functional hybrid nanocomposites as a new platform for drug delivery systems
Full text linkNanoparticle-cored dendrimers (NCDs) are now offering themselves as versatile carriers because of their colloidal stability, tunable membrane properties and ability to encapsulate or integrate a broad range of drugs and molecules. This kind of hybrid nanocomposite aims to combine the advantages of stimuliresponsive dendritic coatings, in order to regulate the drug release behaviour under different conditions and improve the biocompatibility and in vivo half-time circulation of the inorganic nanoparticles. Size, surface chemistry and shape are key nanocarrier properties to evaluate. Here, we have reviewed the most recent advances of NCDs in drug delivery systems, compared their behaviour with non-dendritic stabilized nanoparticles and highlighted their challenges and promising applications in the futureFil: Brunetti, Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto de Investigaciones En Físicoquímica de Córdoba; Argentina; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Bouchet, Lydia María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto de Investigaciones En Físicoquímica de Córdoba; Argentina; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Strumia, Miriam Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina. Universidad Nacional de Córdoba; Argentin
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Dendritic Chemistry Applied to the Construction of Tailored Functional Nanomaterials: Synthesis and Characterization of Gold Nanoparticle-Cored Dendrimers (NCDs)
Full text linkA family of Newkome-type dendritic molecules bearing a disulfide anchor group, different peripheral groups (-COOtBu or -COOH) and sizes or generations (Gn=0-2) was synthesized and used as ligand for the synthesis of gold nanoparticle-cored dendrimers (NCDs). These hybrid materials were characterized by means of UV-vis spectroscopy, TEM, and IR and NMR spectroscopies, finding that the capping molecules of the organic shell determine the solubility and stability of the different NCDs, as well as the characteristics of the inorganic core through a dendritic control characteristic for Newkome-type ligands. Remarkably, a combination of detailed IR and NMR studies allows for studying the ligand-ligand and ligand-core interactions that take place in these materials. It is demonstrated that concepts, techniques and methods normally used in organic and dendritic chemistry, such as the synthesis of precisely controlled architectures and their rigorous spectroscopic characterization, can be efficiently applied to engineer novel organic-inorganic hybrid materials with enhanced properties.Fil: Paez, Julieta Irene. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); ArgentinaFil: Brunetti, Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto de Investigaciones En Físicoquímica de Córdoba; ArgentinaFil: Coronado, Eduardo A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto de Investigaciones En Físicoquímica de Córdoba; ArgentinaFil: Strumia, Miriam Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentin
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