1,721,002 research outputs found
Exopolysaccharide Matrix Of Developed Candida Albicans Biofilms After Exposure To Antifungal Agents
No full textThis study aimed to evaluate the effects of fluconazole or nystatin exposure on developed Candida albicans biofilms regarding their exopolysaccharide matrix. The minimal inhibitory concentration (MIC) against fluconazole or nystatin was determined for C. albicans reference strain (ATCC 90028). Poly(methlymethacrylate) resin (PMMA) specimens were fabricated according to the manufacturer's instructions and had their surface roughness measured. Biofilms were developed on specimens surfaces for 48 h and after that were exposed during 24 h to fluconazole or nystatin prepared in a medium at MIC, 10 x MIC or 100 x MIC. Metabolic activity was evaluated using an XTT assay. Production of soluble and insoluble exopolysaccharide and intracellular polysaccharides was evaluated by the phenol-sulfuric method. Confocal laser scanning microscope was used to evaluate biofilm architecture and percentage of dead/live cells. Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level. The presence of fluconazole or nystatin at concentrations higher than MIC results in a great reduction of metabolic activity (p0.05). The exposure to nystatin also did not alter the exopolysaccharide matrix at all the tested concentrations (p>0.05). Biofilm architecture was not affected by either of the antifungal agents (p>0.05). Nystatin promoted higher proportion of dead cells (p<0.05). It may be concluded that fluconazole and nystatin above the MIC concentration reduced the metabolic activity of C. albicans biofilms; however, they were not able to alter the exopolysaccharide matrix and biofilm architecture.236716722Gendreau, L., Loewy, Z.G., Epidemiology and etiology of denture stomatitis (2011) J Prosthodont, 20, pp. 251-260Tobudic, S., Kratzer, C., Lassnigg, A., Presterl, E., Antifungal susceptibility of Candida albicans in biofilms (2012) Mycoses, 55, pp. 199-204Chaffin, W.L., Candida albicans cell wall proteins (2008) Microbiol Mol Biol Rev, 72, pp. 495-544Seneviratne, C.J., Jin, L., Samaranayake, L.P., Biofilm lifestyle of Candida: A mini review (2008) Oral Dis, 14, pp. 582-590Ramage, G., Rajendran, R., Sherry, L., Williams, C., Fungal biofilm resistance (2012) Int J Microbiol, , 528-521Chandra, J., Kuhn, D.M., Mukherjee, P.K., Hoyer, L.L., McCormick, T., Ghannoum, M.A., Biofilm formation by the fungal pathogen Candida albicans: Development, architecture, and drug resistance (2001) J Bacteriol, 183, pp. 5385-5394Konopka, K., Dorocka-Bobkowska, B., Gebremedhin, S., Duzgunes, N., Susceptibility of Candida biofilms to histatin 5 and fluconazole (2010) Antonie Van Leeuwenhoek, 97, pp. 413-417Baillie, G.S., Douglas, L.J., Effect of growth rate on resistance of Candida albicans biofilms to antifungal agents (1998) Antimicrob Agents Chemother, 42, pp. 1900-1905Niimi, M., Firth, N.A., Cannon, R.D., Antifungal drug resistance of oral fungi (2010) Odontology, 98, pp. 15-25Ramage, G., Mowat, E., Jones, B., Williams, C., Lopez-Ribot, J., Our current understanding of fungal biofilms (2009) Crit Rev Microbiol, 35, pp. 340-355Baillie, G.S., Douglas, L.J., Matrix polymers of Candida biofilms and their possible role in biofilm resistance to antifungal agents (2000) J Antimicrob Chemother, 46, pp. 397-403Seneviratne, C.J., Jin, L.J., Samaranayake, Y.H., Samaranayake, L.P., Cell density and cell aging as factors modulating antifungal resistance of Candida albicans biofilms (2008) Antimicrob Agents Chemother, 52, pp. 3259-3266da Silva, W.J., Seneviratne, J., Samaranayake, L.P., Del Bel Cury, A.A., Bioactivity and architecture of Candida albicans biofilms developed on poly (methyl methacrylate) resin surface (2010) J Biomed Mater Res B Appl Biomater, 94, pp. 149-156(2008) Reference Method For Broth Dilution Antifungal Susceptibility Testing of Yeasts, Approved Standard, , CLSI, CLSI Document M27-A3, Wayne, PA:CLSIda Silva, W.J., Seneviratne, J., Parahitiyawa, N., Rosa, E.A., Samaranayake, L.P., Del Bel Cury, A.A., Improvement of XTT assay performance for studies involving Candida albicans biofilms (2008) Braz Dent J, 19, pp. 364-369Tenuta, L.M., Ricomini, F.A.P., Del Bel Cury, A.A., Cury, J.A., Effect of sucrose on the selection of mutans streptococci and lactobacilli in dental biofilm formed in situ (2006) Caries Res, 40, pp. 546-549Dubois, M., Gilles, K., Hamilton, J.K., Rebers, P.A., Smith, F., A colorimetric method for the determination of sugars (1951) Nature, 28, p. 167. , 168Heydorn, A., Nielsen, A.T., Hentzer, M., Sternberg, C., Givskov, M., Ersboll, B.K., Quantification of biofilm structures by the novel computer program COMSTAT (2000) Microbiology, 146, pp. 2395-2407Force, R.W., Nahata, M.C., Salivary concentrations of ketoconazole and fluconazole: Implications for drug efficacy in oropharyngeal and esophageal candidiasis (1995) Ann Pharmacother, 29, pp. 10-15Gomes, P.N., da Silva, W.J., Pousa, C.C., Narvaes, E.A., Del Bel Cury, A.A., Bioactivity and cellular structure of Candida albicans and Candida glabrata biofilms grown in the presence of fluconazole (2011) Arch Oral Biol, 56, pp. 1274-1281Ellepola, A.N., Samaranayake, L.P., Oral candidal infections and antimycotics (2000) Crit Rev Oral Biol Med, 11, pp. 172-198Ellepola, A.N., Samaranayake, L.P., The postantifungal effect (PAFE) of antimycotics on oral C. albicans isolates and its impact on candidal adhesion (1998) Oral Dis, 4, pp. 260-267Nett, J.E., Sanchez, H., Cain, M.T., Andes, D.R., Genetic basis of Candida biofilm resistance due to drug-sequestering matrix glucan (2010) J Infect Dis, 202, pp. 171-175Mores, A.U., Souza, R.D., Cavalca, L., de Paula e Carvalho, A., Gursky, L.C., Rosa, R.T., Enhancement of secretory aspartyl protease production in biofilms of Candida albicans exposed to subinhibitory concentrations of fluconazole (2011) Mycoses, 54, pp. 195-201Goncalves, L.M., Del Bel Cury, A.A., Sartoratto, A., Garcia, R.V.L., Silva, W.J., Effects of undecylenic acid released from denture liner on Candida biofilms (2012) J Dent Res, 91, pp. 985-98
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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