1,720,992 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
Activity of 3-carbethoxyangelicin photolysis products
No full text3-Carbethoxyangelicin (3-CA), carrying an electron-withdrawing group at the pyrone side, has been prepared to have a fully monofunctional angelicin derivative. 3-CA does not photoreact with DNA and induces a moderate antiproliferative activity. 3-CA proved to be extremely sensitive to ultraviolet A (UVA) light, undergoing rapid photolysis. Only one photolysis product has been isolated and identified. By means of alkaline elution, we observed that 3-CA and its photolysis products are able to induce a large amount of single-strand breaks in DNA in vivo. The results obtained from studying the capacity to produce singlet oxygen suggest that the photodynamic mechanism of action of 3-CA very likely results from its capacity-as well as that of its photolysis products-to produce singlet oxygen. (C) 1997 Elsevier Science S.A
Synthesis, biological evaluation and molecular modelling studies on benzothiadiazine derivatives as PDE4 selective inhibitors
No full textA series of 2,1,3- and 1,2,4-benzothiadiazine derivatives (BTDs) were synthesized and evaluated for their inhibitory activity versus enzymatic isoforms PDE3, PDE4 and PDE7. The compounds characterized by the 3,5-di-tert-butyl-4-hydroxybenzyl moiety at NI position of 2,1,3-benzothiadiazine core (8, 13, 18), were found active and selective at micromolar level versus PDE4 and could be studied as new leads for the treatment of asthma and COPD (Chronic Obstructive Pulmonary Disease). The antioxidant activity evaluation on the same compounds highlighted 13 as the most significative. Molecular modelling studies gave further support to biological results and suggested targeted modifications so as to improve their potency. (C)2004 Elsevier Ltd. All rights reserved
Novel angular Furo and thieno-quinolinones: synthesis and preliminary photobiological studies
No full textA number of new furo and thienoquinolinones carrying an electron-withdrawing function or unsubstituted at the position 3 were synthesized in order to obtain new potential photochemotherapeutic agents with increased anti proliferative activity and decreased toxic side effects. Our interest in studying the SAR of these derivatives also prompted us to investigate the influence of N-methylation on biological activity, by preparing N-methyl derivatives. The antiproliferative activity of all the newly synthesized compounds was evaluated and compared to 8-methoxypsoralen (8-MOP), the drug widely used in PUVA-therapy. The 3-unsubstituted thienoquinolinones were generally the most potent derivatives, followed by the furo-analogues. In particular. the unsubstituted thieno[2.3-h]quinoline-2(1H)one showed the highest activity in T2 bacteriophage, HeLa cells and Ehrlich cells tests. All the compounds, assayed on Escherichia coli WP2 TM9, showed a similar mutagenic activity, very close to that of 8-MOP. Except for 2-oxo-1,2-dihydrothieno[2.3-h]quinoline-3-carboxylic acid, which appeared to be very effective, all compounds generated singlet oxygen to slightly larger amounts when compared to 8-MOP. The N-methyl analogues only induced moderate skin erythemas on albino guinea pigs, while all other derivatives appeared to be entirely inactive. On the basis of these results, the unsubstituted thieno[2,3h]quinoline 2(1H)one seems to be the most interesting potential drug for PUVA photochemotherapy and photopheresis. (C) 2002 Elsevier Science Ltd. All rights reserved
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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