1,720,986 research outputs found
The effect of some antibiotics on glutathione reductase enzyme purified from liver and erythrocyte of Lake Van pearl mullet
No full textContext: The effect of antibiotics (amikacin, cefazolin, ivermectin, and kanamycin) on glutathione reductase (GR) isoenzymes activity in liver and erythrocyte of the fish, Chalcalburnus tarichi (Lake Van pearl mullet, Pallas 1811) (Cyprinidae) were investigated.
Objective: This study determined the biochemical characterization of GR purified from the liver and erythrocytes of C. tarichi and the inhibition effect of the antibiotics on the GR isoenzymes.
Materials and methods: GR was purified by affinity chromatography from the tissues of C. tarichi. The biochemical characterization of GR such as optimum temperature, optimum pH, and ionic strength were determined. The inhibition effects of the antibiotics on the isoenzymes were evaluated as IC50 and K-i values. K-i constant and 50% inhibitory concentration (IC50) value for antibiotics were determined by Lineweaver-Burk graphs and plotting activity % versus [ I], respectively, at five different concentrations of antibiotics.
Results: Optimum temperature, pH, and ionic strength were determined for isoenzymes as 40 degrees C, 60 degrees C; 8.0, 8.0, and 50, 50 mM, respectively. Subunit molecular weights of the isoenzymes were estimated as 55 kDa by sodium dodecyl sulfate polyacrilamide gel electrophoresis (SDS-PAGE). In addition, IC50 and K-i values were calculated for amikacin, cefazolin, ivermectin, and kanamycin. The antibiotics showed non-competitive inhibition effects. IC50 values were calculated as 16.3, 36.6, 0.504, and 18.8mM for liver and 20.0, 30.4, 0.787, and 31.8 mM for erythrocyte, respectively. K-i constants were 13.9, 18.4, 0.654, and 11.2 mM for liver and 23.2, 46.4, 1.19, and 36.4 mM for erythrocyte, respectively.
Discussion and conclusion: The results indicated that the antibiotics displayed non-competitive inhibition
Insecticidal activity of fatty acid-rich Turkish bryophyte extracts against sitophilus granarius (coleoptera: curculionidae)
Full text linkThis work was supported by grants from Cankiri Karatekin University and the State Planning Organization, Turkey (Project No: 2010K120720). The authors would also like to thank Turkish Republic Ministry of Forestry and Water Affairs, General Directorate of Nature Protection and National Parks for permission to collect the mosses Dicranum scoparium and Hypnum cupressiforme from Ilgaz Mountain National Park. Finally, the authors thank Bianka Martinez for grammatical revision of the manuscript.The composition of fatty acids and insecticidal effects was performed for the Turkish mosses Dicranum scoparium, Hypnum cupressiforme, Polytrichastrum formosum, Homalothecium lutescens and the Turkish liverwort Conocephalum conicum. All structures were determined by means of gas chromatography and gas chromatography-mass spectrometry techniques. The determination of fatty acids was done using a simple and mild method that utilized different solvent extractions ranging from nonpolar to polar solvents (hexane, dichloromethane, chloroform, ethyl acetate and methanol, respectively), and the samples were powdered with and without liquid nitrogen. The correlations between the saturated and unsaturated fatty acid contents depending on the solvent polarity and their crushing process by liquid nitrogen were observed. The insecticidal activity of the bryophytes was analyzed by using the methanol, hexane and esterified methanol extracts. The hexane extracts of Polytrichastrum formosum showed the highest insecticidal activity (70.33%) against Sitophilus granarius. Contact toxicity activities of lauric, myristic and palmitic acids besides single dose studies of the solvent extracts were carried out. The highest mortality rate (53.34%) was obtained from the myristic acid among the tested pure fatty acids. The activities of palmitic and lauric acids were 17.75% and 4.32%, respectively
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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