1,720,958 research outputs found
On the Different Mode of Action of Au(I)/Ag(I)-NHC Bis-Anthracenyl Complexes Towards Selected Target Biomolecules
Full text linkGold and silver N-heterocyclic carbenes (NHCs) are emerging for therapeutic applications. Multiple techniques are here used to unveil the mechanistic details of the binding to different biosubstrates of bis(1-(anthracen-9-ylmethyl)-3-ethylimidazol-2-ylidene) silver chloride [Ag(EIA)2]Cl and bis(1-(anthracen-9-ylmethyl)-3-ethylimidazol-2-ylidene) gold chloride [Au(EIA)2]Cl. As the biosubstrates, we tested natural double-stranded DNA, synthetic RNA polynucleotides (single-poly(A), double-poly(A)poly(U) and triple-stranded poly(A)2poly(U)), DNA G-quadruplex structures (G4s), and bovine serum albumin (BSA) protein. Absorbance and fluorescence titrations, mass spectrometry together with melting and viscometry tests show significant differences in the binding features between silver and gold compounds. [Au(EIA)2]Cl covalently binds BSA. It is here evidenced that the selectivity is high: low affinity and external binding for all polynucleotides and G4s are found. Conversely, in the case of [Ag(EIA)2]Cl, the binding to BSA is weak and relies on electrostatic interactions. [Ag(EIA)2]Cl strongly/selectively interacts only with double strands by a mechanism where intercalation plays the major role, but groove binding is also operative. The absence of an interaction with triplexes indicates the major role played by the geometrical constraints to drive the binding mode
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
Triethylphosphine gold iodide (I), the iodido analogue of Auranofin: comparative studies of a potential antineoplastic agent
No full textAuranofin [2,3,4,6-tetra-o-acetyl-L-thio-β-D-glycopyranosato-S-(triethyl- phosphine)-gold(I)] (AF) is an important oral chrysotherapeutic agent of established clinical efficacy in the treatment of rheumatoid arthritis. In the last few years, this drug has attracted growing attention for its important pharmacological properties as a prospective anticancer and antibacterial agent according to innovative drug repurposing strategies. Selective chemical modification of auranofin might lead to a modulation and hopefully an improvement of its pharmacological profiles.
Accordingly, we decided to prepare an AF derivative where the thiosugar ligand is replaced by iodide i.e. triethylphosphine gold iodide (I). Replacement of the thiosugar ligand with iodide should afford a compound of increased lipophilicity thus favoring bioavailability.
The novel compound was investigated in depth for its chemical and biological properties in comparison to AF and to its chlorido analogue. Solution behavior was assessed by 31P NMR spectroscopy and the crystal structure solved. To better characterise the molecular aspects of the interaction of these drugs with biological targets, we studied their reactivity toward the model protein lysozyme, a GG rich oligonucleotide, and ds ctDNA, through ESI-MS and ethidium bromide assay.
Upon replacing the thiosugar with different halides i.e. chloride and iodide, we assisted to complete inhibition of reactivity toward proteins, at variance with AF that interacts with HEWL through the formation of non-covalent adduct. Replacement of thiosugar with halide ligands, instead, does not inhibit the reactivity toward DNA models.
Antiproliferative properties of I were comparatively determined on HCT8 and HCT116 cells, two representative cell lines of colorectal cancer (CRC), highlighting the potent cytotoxic effect of these compounds on CRC cell lines, with an IC50 value falling in the nM range. Furthermore, cell cycle and apoptosis experiments were carried out to investigate whether the structural modification made on AF imply differences in the mechanisms through which apoptosis and cell cycle arrest are triggered.
Overall, we believe that this novel analogue of AF manifests a number of chemical and biological features that render it particularly interesting and suitable for further preclinical testing in appropriate in vivo models of CRC
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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