1,720,973 research outputs found
Antibacterial and antitumoral activities of new organotin(IV)-Schiff bases derivatives
No full textThis preliminary report shows eight complexes of triorganotin(IV): Ph3SnOH and (CH3)3SnOH with four chelating imines on new synthesis. Of these ligands, two are salen-like (four coordination sites, two imidic, two phenoxidic) [1], one is a tetradentate pyrrole derivative [2] while the fourth, a vita- min B6 derivative, is pentadentate [3]. Ligands have been characterized by means of FT-IR, UV-Vis, Fluorescence, 1H- and 13C-NMR, LC-MS ESI triple quadrupole; complexes by means FT-IR, 1H- and 119Sn-NMR, LC-MS ESI, using the isotopic distribution pattern as a discriminant [4]. Geometry and nature of coordination complexes have been also evaluated using the 119Sn chemical shifts. Solid-state synthesis of the complexes (with a ball mill [5]) was also explored; such method reduces both solvent consumption and time – from 8-10 h under controlled atmosphere to about 1 h, with results identical to the wet synthesis. Antitumoral and antibacterial activities of the triorganotin (IV) complexes (BS01M, BS01P, BS02M, BS02P, BS03M, BS03P, BS04M, BS04P) were tested in vitro. In both analyses, the Shiff bases alone showed no biological activity. Antimicrobial activity was evaluated by Kirby-Bauer method against the Gram-negative Escherichia coli, and the two Gram-positive Kocuria rizophila and Staphylococcus aureus strains. All the ML2 complexes were active in inhibiting bacterial growth, with BS02P and BS03P showing the best antibacterial performance. Among the ML complexes, BS01M was not active, BS02M showed a weak antibacterial activity only against the Gram-positive bacteria, BS04M was mainly active against the Gram-negative E. coli and BS03M was active against all the tested strains. Antitumor activity was evaluated by MTT assay against cervical (HeLa), colon adenocarcinoma (HT- 29) and breast (MDA-MB231) cancer cell lines. Results showed that ML2 complexes are more active than ML ones, with HeLa cells more sensitive to treatments. These complexes (especially the ML2) showed promising results; their mechanism of action is under investigation. References 1. K. Tayade, S.K. Sahoo, S. Chopra, N. Singh, Inorganica Chimica Acta, 421, 538-543 (2014); https://doi.org/10.1016/j. ica.2014.05.014 2. S. Meghdadi, M. Amirnasr, K. Mereiter, Polyhedron, 30, 1651-1656 (2011); https://doi.org/10.1016/j.poly.2011.03.041 3. D. Sharma, S.K. Sahoo, S. Chaudhary, R. Kanta Bera, J.F. Callan, Analyst, 138, 3646-3650 (2013); https://doi.org/10.1039/ C3AN00199G 4. G. Lawson, R.H. Dahm, N. Ostah, E.D. Woodland, Applied Organometallic Chemistry, 10, 125-133 (1996); https://doi. org/10.1002/(SICI)1099-0739(199603)10:2<125::AID-AOC491>3.0.CO;2-1 5. G.A. Bowmaker, Chemical Communications, 49, 334-348 (2013); http://doi.org/10.1039/C2CC35694E 6. R. Di Stefano, M. Scopelliti, C. Pellerito, G. Casella, T. Fiore, G.C. Stocco, R. Vitturi, L. Ronconi, I.D. Sciacca, L. Pellerito, Journal of Inorganic Biochemistry, 98, 534-546 (2004); https://doi.org/10.1016/j.jinorgbio.2003.12.013 7. C. Pellerito, L. Nagy, L. Pellerito, A. Szorcsik, Journal of Organometallic Chemistry, 691, 1733-1747 (2006); https://doi. org/10.1016/j.jorganchem.2005.12.02
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
MATRIX METALLOPROTEINASES (MMPs) IN FOLLICULAR FLUIDS (FF) AND FF-DERIVED EXTRACELLULAR VESICLES (EVs) FROM PATIENTS UNDERGOING TO IN VITRO FERTILIZATION (IVF) TECHNIQUES
No full textProceedings of the 68th Congress of the Italian Embryological Group-Italian Society of Development and Cell Biology (GEI-SIBSC) - Oliveri, 5-8 June 2023
Functional investigations of matrix metalloproteinases in breast cancer: focus on MMP9 and MMP2
No full textDispelling 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
Potentially useful diagnostic and prognostic markers in colon cancer: a proteomic-based investigation
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