1,721,011 research outputs found
Impact of Protein Concentration on the Determination of Thiolic Groups of Ovalbumin: A Size Exclusion Chromatography-Chemical Vapor Generation-Atomic Fluorescence Spectrometry Study via Mercury Labeling
No full textWe optimized a hyphenated system based on size exclusion chromatography coupled to a microwave/UV mercury oxidation system and an atomic fluorescence detector (SEC–CVG–AFS) for the online oxidation of free and protein-complexed p-hydroxymercuribenzoic acid (pHMB) without the employment of chemical oxidizing agents. This system has been applied to the study of labeling of thiolic groups of native ovalbumin (OVA) as a function of protein concentration. We found that the protein concentration strongly affects the species distribution of OVA, the number of thiolic groups titrated in each species, and thus, the accuracy in the determination of the total number of thiolic groups. The amount of titrated sulfhydryl groups in the protein concentration range investigated (5–100 μmol L–1) varied from 2.40 ± 0.01 to 1.85 ± 0.05 for the monomeric form of OVA and from 4.63 ± 0.01 to 5.63 ± 0.05 for the total OVA, which represents more than four theoretical number of reduced Cys. This information is important from the analytical point of view because it suggests that, unless to operate with diluted concentration of protein, the number of titrated thiolic groups results from both the aspecific interaction of the probe with aggregates species and to the specific bond of the probe with the accessible −SH groups
Characterization of Denatured Metallothioneins by Reversed Phase Coupled with On Line Chemical Vapour Generation and Atomic Fluorescence Spectrometric Detection (RP-CVGAFS)
No full textStudy of the Disulfides Reduction of Denatured Proteins by Liquid Chromatography Coupled with On-Line Cold Vapor Generation Atomic Fluorescence Spectrometry (LC-CVGAFS)
No full textMercury speciation by Liquid Chromatography Coupled with On Line Chemical Vapour Generation and Atomic Fluorescence Spectrometric Detection (LC-CVGAFS)
No full textInteraction of collagen with chlorosulphonated paraffin tanning agents: Fourier transform infrared spectroscopic analysis and molecular dynamics simulations
No full textHydrophobic Interaction Chromatography coupled with Atomic Fluorescence Spectrometric Detection. Effect of the Denaturation on the Determination of Thiolic Proteins
No full text
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
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