1,721,103 research outputs found
Stereoselective Ring Opening of Bicyclic Nitroso Diels-Alder Cycloadducts with Carbon Nucleophiles
No full textRegio- and Stereoselective Ring Opening of Hetero Diels-Alder Cycloadducts with Organometallic Reagents
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Copper-Catalyzed Perkin Acyl-Mannich Reaction of AceticAnhydride with Pyridine: Expeditious Entry to Unconventional Piperidines
No full textA regioselective introduction of a methoxycarbonyl methyl group at the C2 position of unsubstituted pyridine has been accomplished with catalytic amounts of copper(II) triflate in mild reaction conditions. The N-acetyl-1,2-dihydropyridyl acetic acid methyl ester obtained is a valuable building block for the synthesis of new polyfunctionalized piperidine derivatives bearing unconventional substitution pattern
Regio- and Stereoselective Copper-Catalyzed Ring Opening of Diheterobicyclic Alkenes with Grignard Reagents
No full textThe ring opening of bicyclic hydrazines and bicyclic oxazines with organomagnesium reagents under the influence of copper catalysts allows functionalized cyclopentene and cyclohexene derivs. to be obtained. Whereas complete anti-stereoselective ring opening occurred in all cases, the regioselective outcome turned out to be highly dependent on the reaction conditions use
Voltammetric responses at modified electrodes and aggregation effects of two anticancer molecules: Irinotecan and sunitinib
Full text linkThe voltammetric responses of two anticancer molecules irinotecan (ITC) and sunitinib (SUN) were investigated at glassy carbon (GC) and indium tin oxide (ITO) electrodes bare or modified with carbon nanotubes (NTs), NT-Nafion composites (NafionNTs) and poly(3,4-ethylenedioxy-thiophene) (PEDOT). Bare GC electrodes revealed to be the most suitable for the detection of drugs at low concentration levels. Differential pulse voltammetry (DPV) analyses showed that the responses of the anticancer molecules are affected by the formation of aggregates. In particular, aggregation of SUN results in the formation of H-aggregates. DPV analysis extended to human plasma samples revealed the drugs in micromolar concentrations with good reproducibility
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
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