1,721,010 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
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
Physico-chemical investigation on the interaction between ochratoxin A and heptakis-2,6-di- O-methyl--cyclodextrin
No full textThe interaction of ochratoxin A (OTA) with heptakis-2,6-di-O-methyl-β-cyclodextrin (DIMEB) in aqueous solutions at two different pHs (3.5 and 9.5) was studied by means of spectroscopic, calorimetric and electrochemical techniques. DIMEB affected the physico-chemical properties of OTA. A stronger interaction was observed at pH = 3.5 where the neutral form of OTA prevails. The spectroscopic information indicated that the OTA/DIMEB inclusion process occurred through the insertion of the phenylalanine group into the cyclodextrin (CD) cavity; moreover, voltammetry experiments showed that the isocoumarinic phenolic group was also involved, probably by non-inclusion interactions. At pH = 3.5, binding constants and thermodynamic parameters of the OTA/DIMEB complex were determined by means of the modified Benesi-Hildebrand equation and van’t Hoff plot. A 1:1 stoichiometry for the OTA/DIMEB complex was observed with a binding constant equal to 530 ± 50 L·mol−1 at 25 °C. The calculated thermodynamic parameters indicate that the interaction is highly endothermic and that the complex formation is driven by entropy. The results provide useful information for potential applications of cyclodextrins in the analysis of mycotoxins and in the field of mycotoxin sequestering agent
Chlorophyll/Alginate microparticles for Photodynamic Therapy applications
No full textThe goal of this study is the chemical-physical characterization of a drug delivery system for Photodynamic Therapy (PDT) [1]: Chlorophyll a (Chl a) entrapped in a water-soluble matrix made of Ca2+ cross-linked alginic acid [2]. Chl a, a lipophilic natural pigments, is a molecule with characteristic photosensitising properties usable in PDT. In PDT the photosensitizer, selectively accumulated in malignant tissues, produces, upon light irradiation, reactive oxygen species (ROS) which are responsible for cytotoxicity of neoplastic cells and tumor regression since induce cellular damage via apoptosis, necrosis, or both. The Chl a/alginate microspheres produced were characterized by means of different techniques as UV-Vis absorption and emission spectroscopy, FT-IR spectroscopy, Atomic Force Microscopy, Dynamic Light Scattering and Differential Scanning Calorimetry. Moreover, it was estimated the ROS production, mainly singlet oxygen (1O2) by means of a selective luminescent probe, Singlet Oxygen Sensor Green [3] and in vitro tests were carried out on human adenocarcinoma cells (HT29).
[1] R.M. Szeimies, S. Karrer, S. Radakovic-Fijan. J. Am. Acad. Dermatol., 2002, 47, 259-262. [2] G.T. Grant, E.R. Morris, D.A. Rees, P.J.C. Smith, D. Thom. FEBS letters, 1973, 32,195-198. [3] A. Gollmer, J. Arnbjerg, H. Frances, F.H. Blaikie, B.Wett Pedersen, T. Breitenbach, K. Daasbjerg, P.R. Ogilby. Photochemistry and Photobiology, 2011, 87, 671–679
Chlorophyll a in cyclodextrin supramolecular complexes as a natural photosensitizer for photodynamic therapy (PDT) applications
No full textChlorophyll a (Chl a), an amphipathic porphyrin, was employed as natural photosensitizer for photodynamic therapy applications. Due to its lacking solubility in water and high tendency to aggregate, Chl a was included into different modified cyclodextrins (CDs) to form stable water-soluble supramolecular complexes. To achieve this aim, 2-Hydroxypropyl-β-cyclodextrin (2-HP-β-CD), 2-Hydroxypropyl-γ-cyclodextrin (2-HP-γ-CD), Heptakis(2,6-di-o-methyl)-β-cyclodextrin (DIMEB) and Heptakis(2,3,6-tri-o-methyl)-β-cyclodextrin (TRIMEB) were used. The chemical physical properties of Chl a/CD complexes in cellular medium were studied by means of UV–Vis absorption spectroscopy. Results demonstrated the good aptitude of 2-HP-γ-CD, and more particularly of 2-HP-β-CD, to solubilize the Chl a in cell culture medium in monomeric and photoactive form. Then, Chl a/2-HP-β-CD and Chl a/2-HP-γ-CD complexes were evaluated in vitro on human colorectal adenocarcinoma HT-29 cell line, and cytotoxicity and intracellular localization were respectively assessed. Further tests, such as phototoxicity, ROS generation, intracellular localization and mechanism of cell death were then focused exclusively on Chl a/2-HP-β-CD system. This complex exhibited no dark toxicity and a high phototoxicity toward HT-29 cells inducing cell death via necrotic mechanism. Therefore, it is possible to affirm that Chl a/2-HP-β-CD supramolecular complex could be a promising and potential formulation for applications in photodynamic therapy
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