1,720,961 research outputs found
Short Synthesis of Chiral Tentacled Porphyrins using Pyrrolylmagnesiumbromide and (3R)-(+)-Citronellal.
No full textSynthesis and characterization of square planar nickel(II) complexes with p-fluorobenzaldehyde thiosemicarbazone derivatives
No full textSynthesis, Characterisation and Conformational Studies of Lipophilic, Amphiphilic and Water-Soluble C-Glyco-Conjugated Porphyrins.
No full textSynthesis, characterization, biological activity of natural aldehydes thiosemicarbazones and their first transition series metal complexes
No full textZinc complexes with cyclic derivatives of alpha-ketoglutaric acid thiosemicarbazone: synthesis, X-ray structures and DNA interactions
No full textAbstract
Six new cyclic ligands derived from a-ketoglutaric acid thiosemicarbazone (H3ct) and their zinc complexes have been synthesized
and characterized by analytical and spectroscopic (IR and NMR) studies. The X-ray structures of ligands Me-H2ctC (1), Allyl-H2ctc
(3) and of complex [Zn(Me-HctC)2(OH2)2] Æ 2H2O (7) have been determined. In complex (7) the zinc atom lies on a twofold axis and
is surrounded in a tetrahedral coordination by two water molecules and two carboxylic oxygen donor atoms from the ligand. DNA
titration in the UV–visible region and thermal denaturation have been employed to determine the details of DNA binding for the
studied compounds. Studies of nuclease activity have also been performed with all our compounds through a gel electrophoresis
experiment using plasmid pBR322 showing that no DNA breakings take place. Tests in vitro on human leukemia cell line U937
have been carried out on cell growth inhibition where solubility of the compounds allowed the experiments
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
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