1,720,973 research outputs found
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
Protein metalation by metal-based drugs: reactions of cytotoxic gold compounds with cytochrome c and lysozyme
No full textProtein metalation processes are crucial for the
mechanism of action of several anticancer metallodrugs
and warrant deeper characterisation. We have explored the
reactions of three cytotoxic gold(III) compounds—namely
[(bipy2Me)2Au2(l-O)2][PF6]2 (where bipy2Me is 6,60-dimethyl-
2,20-bipyridine) (Auoxo6), [(phen2Me)2Au2(l-O)2]
[PF6]2 (where phen2Me is 2,9-dimethyl-1,10-phenanthroline)
(Au2phen) and [(bipydmb-H)Au(OH)][PF6] [where
bipydmb-H is deprotonated 6-(1,1-dimethylbenzyl)-2,20-
bipyridine] (Aubipyc)—with two representative model
proteins, i.e. horse heart cytochrome c and hen egg whitelysozyme, through UV–visible absorption spectroscopy
and electrospray ionisation mass spectrometry (ESI MS) to
characterise the inherent protein metalation processes.
Notably, Auoxo6 and Au2phen produced stable protein
adducts where one or more ‘‘naked’’ gold(I) ions are protein-
coordinated; very characteristic is the case of cytochrome
c, which upon reaction with Auoxo6 or Au2phen
preferentially forms ‘‘tetragold’’ adducts with four proteinbound
gold(I) ions. In turn, Aubipyc afforded monometalated
protein adducts where the structural core of the
gold(III) centre and its ?3 oxidation state are conserved.
Auranofin yielded protein derivatives containing the intact
auranofin molecule. Additional studies were performed to
assess the role played by a reducing environment in protein
metalation. Overall, the approach adopted provides
detailed insight into the formation of metallodrug–protein
derivatives and permits trends, peculiarities and mechanistic
details of the underlying processes to be highlighted.
In this respect, electrospray ionisation mass spectrometry is
a very straightforward and informative research tool. The
protein metalation processes investigated critically depend
on the nature of both the metal compound and the interacting
protein and also on the solution conditions used;
thus, predicting with accuracy the nature and the amounts
of the adducts formed for a given metallodrug–protein pair
is currently extremely difficult
Chemistry and biology of three representative gold(III) compounds as prospective anticancer agents
No full textAubipyc, i.e.[(bipydmb-H)Au(OH)][PF6] (where bipydmb-H = deprotonated 6-(1,1-dimethylbenzyl)-2,20-
bipyridine), Auoxo6, i.e. [(bipy2Me)2Au2(l-O)2][PF6]2 (where bipy2Me = 6,60-dimethyl-2,20-bipyridine)
and Au2phen i.e. [(phen2Me)2Au2(l-O)2][PF6]2 (where phen2Me = 2,9-dimethyl-1,10-phenanthroline), are
three representative gold(III) compounds prepared and characterised in our laboratories during the last
few years that manifested remarkable anticancer properties in vitro. Herein, the main chemical features
of these compounds are summarised. Aubipyc is a mononuclear organogold(III) compound while Auoxo6
and Au2phen are binuclear gold(III) complexes. These compounds manifest a reasonable stability of their
gold(III) chromophore in aqueous solutions at physiological pH; yet, a rather different redox behaviour
was highlighted as Aubipyc displays high stability toward reduction while both Auoxo6 and Au2phen
are rapidly reduced by ascorbic acid and glutathione. The antiproliferative properties of these gold(III)
compounds were analysed in detail against a wide panel of human tumour cell lines. Remarkably,
Auoxo6 and Au2phen revealed potent and rather similar patterns of antiproliferative actions while
Aubipyc turned out to be less effective. For Auoxo6 and Au2phen more detailed biochemical studies
are available documenting their effects on the proteome of treated cancer cells. Recent studies described
the reactions of these gold compounds with various proteins at the molecular level; adduct formation
was clearly documented in a few cases and their nature determined. Preliminary results suggest that
these gold compounds may act as strong inhibitors of the selenoenzyme thioredoxin reductase and cause
mitochondrial dysfunction. Based on the available in vitro data, these gold compounds look quite
promising as prospective anticancer agents. Studies will soon be extended to assess their safety and
efficacy in relevant animal models of cancer
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
Chemistry And Biology Of Three Representative Gold(III) Compounds As Prospective Anticancer Agents
No full textThe mode of action of anticancer gold-based drugs: a structural perspective.
No full textThe interactions between a few representative gold-based drugs and
hen egg white lysozyme were studied by X-ray crystallography. High
resolution crystal structures solved for three metallodrug–protein
adducts provide valuable insight into the molecular mechanism
of these promising metal compounds and the inherent protein
metalation processes
The mode of action of anticancer gold-based drugs: a structural perspective
No full textThe interactions between a few representative gold-based drugs and hen egg white lysozyme were studied by X-ray crystallography. High resolution crystal structures solved for three metallodrug-protein adducts provide valuable insight into the molecular mechanism of these promising metal compounds and the inherent protein metalation processes
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
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