1,720,956 research outputs found
Immobilized Enzymes for Resolution of Racemic Organic Substrates Linked to Soluble Polymers
No full textSynthesis, Postmodification and Characterization of Linear Polystyrene-based Supports for the Interaction with Immobilized Biocatalysts
No full textA series of linear polystyrene-based supports has been synthesized using conventional or controlled (reversible addition
fragmentation chain transfer or nitroxide-mediated) free radical polymerizations, in order to modulate their molecular weight
characteristics. Polymer post-modification via esterification of the primary hydroxyl alcohol functionalities, pendant from the
polymer backbone, with a mandelic acid derivative introduces efficiently (>85% yield) racemic, enzyme-cleavable moieties.
A study of the interactions of these polymeric substrates with immobilized penicillin G acylase, in mixed organic/aqueous
buffer solvent systems, results in a modest enantioselectivity (comparable with that of racemicmandelic acid methyl ester), but
reveals that the biocatalytically active moieties on the linear polymers can be cleaved with first-order rate kinetics, as observed
with small molecules in solution; the reaction rates (which can differ by more than one order ofmagnitude) are influenced both
by the synthetic polymer length and by the polymer structure resulting from themethod of polymerization used
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
Cationic Pentaheteroaryls as Selective G-Quadruplex Ligands by Solvent-Free Microwave-Assisted Synthesis
No full textA solvent-free and microwave-assisted synthesis
of several water soluble acyclic penta-heteroaryls containing 1,2,4-oxadiazole moieties (1–7) has been achieved with good yields. Their binding interactions with DNA quadruplex structures were thoroughly investigated by FRET melting, fluorescent intercalator displacement assay (G4-FID) and CD
spectroscopy. Among the G-quadruplexes considered, attention was focused on telomeric repeats together
with the proto-oncogenic c-kit sequences and the c-myc oncogene promoter. Compound 1, and to a lesser extent 2
and 5, preferentially stabilise an antiparallel structure of the telomeric DNA motif, and exhibit an opposite binding behaviour to structurally related polyoxazole (TOxaPy), and do not bind duplex DNA. The efficiency and selectivity of the binding process was remarkably controlled by the structure
of the solubilising moieties
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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