1,721,039 research outputs found
Synthesis, structural characterization and in vitro cytotoxicity of gold complexes with 2-(2-pyridyl)benzimidazole. Gold)III) vs. cold(I), mono- vs. binuclear derivatives
No full textGold compounds are attracting much interest because of their promising pharmacological activity against a series of diseases. Some of these complexes are reported to posses a great potential for cancer treatment, 1 showing important anti proliferative activity both in vitro and in vivo, probably involving thioredoxin reductase inhibition. 2 In this framework, a variety of gold(III) and gold(I) derivatives of 2-(2-pyridyl)benzimidazole (pbiH), both mono- and binuclear, have been synthesized, fully characterized and their biological properties investigated. All complexes show from good to excellent cytotoxic activity in vitro toward the human carcinoma cell line A2780, both sensitive, A2780/S, and resistant, A2780/R, to cisplatin, with IC50 values falling in the low micromolar, and in some case nanomolar, range. In general, the binuclear derivatives were found more active than the corresponding mononuclear ones. Particularly beneficial was joining into the same compound a gold(III) and a gold(I) centre. Reactivity with model proteins (Cytochrome C and Lysozyme) was also studied by ESI MS and UV-visible spectrometry. Methods and results of this study will be presented. Literature [1] Nbili S., Mini E., Landini I., Gabbiani C., Casini A., Messori L., med. Res. Rev., 2010, 30, 550-580. [2] Pratesi A., Gabbiani C., Ginanneschi M., Messori L., Chem. Common., 2010, 46, 7001-700
Dinuclear Gold(III) Complexes as Potential Anticancer Agents. Structure, Reactivity and Biological Profile of a Series of Gold(III) Oxo-Bridged Derivatives
No full textSix homologous gold(III) dinuclear oxo-bridged complexes, of the type [(bipynR)Au(μ-O)2Au(bipynR)][PF6]2,
bearing variously substituted 2,2’-bipyridine ligands (bipynR
= 2,2’-bipyridine, 4,4’-di-tert-butyl-, 6-methyl-, 6-neopentyl-,
6-o-xylyl- and 6,6’-dimethyl-2,2’-bipyridine), here called Auoxos, were prepared, characterised and recently tested as
potential anticancer agents. Crystal structures were obtained for five members of the series that allowed us to perform
detailed comparative analyses. Interestingly, the various Auoxos showed an acceptable stability profile in buffer solution
and turned out to manifest outstanding antitumor properties in vitro. In particular, one member of this family, Auoxo6
(bipynR = 6,6’-dimethyl-2,2’-bipyridine), produced more selective and far greater antiproliferative effects than all other
tested Auoxos, qualifying itself as the best “drug candidate”. In turn, COMPARE analysis of the cytotoxicity profiles of
five Auoxos, toward an established panel of thirty-six human tumor cell lines, revealed important mechanistic differences;
a number of likely biomolecular targets could thus be proposed such as HDAC and PKC. Biophysical studies revealed
markedly different modes of interaction with calf thymus DNA for two representative Auoxo compounds. In addition, a
peculiar reactivity with model proteins was documented on the ground of spectrophotometric and ESI MS data, most
likely as the result of redox processes. In view of the several experimental evidences gathered so far, it can be stated that
Auoxos constitute a novel family of promising cytotoxic gold compounds with an innovative mechanism of action that
merit a more extensive pharmacological evaluation
A focus on the biological targets for coinage metal-NHCs as potential anticancer complexes
Full text linkMetal complexes of N-heterocyclic carbene (NHC) ligands are the object of increasing attention for therapeutic purposes. Among the different metal centres, interest on Au-based compounds started with the application as anti-arthritis drugs. On the other hand, Ag(I) antimicrobial properties have been known for a long time. For Au(I)/Au(III)-NHC and Ag(I)-NHC anti-tumour and anti-proliferative properties have been quite recently demonstrated. In addition to these and as for Group 11, copper is a much less investigated metal centre, but a few papers underline its pharmacological potential. This review wants to focus on the different biological targets for these metal-based compounds. It is divided into chapters which are respectively devoted on: i) mitochondria and thiol oxidoreductase systems; ii) other relevant enzymes; iii) nucleic acids. Examples of representative coinage NHCs for each of the targets are provided together with significant references on recent advances on the topic. Moreover, a final comment summarises the aspects enlightened by each chapter and provides some hints to better understand the metal-NHCs mechanistic behaviour based on structure-activity relationships
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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