1,720,956 research outputs found
Apllication of capillary electrophoresis to analyze human transferrin focusing on the detection and quantification of the asialo-Tf isoform
No full textIn forensic sciences, the analysis of Carbohydrate-deficient transferrin (CDT) is used in the diagnostics of alcohol abuse, because it is known that the concentration of CDT increases after alcohol consumption. The human Transferrin (Tf) is the iron transport serum glycoprotein characterized by oligosaccharide chains that can be n-“antennary” (from zero to four) each one with a sialic-acid residue. Consequently, there are different isoforms with different numbers of sialic-acid residues and CDT includes the monosialo-, the asialo-, and the disialo-Tf isoforms characterized by absence, one or two sialic-acid residues. Currently, CDT analyses are based on the relative quantification of disialo-Tf isoform in respect to the total Tf isoforms identified (up to pentasialo-Tf). At present, the available analytical methods to perform CDT analysis based on immunochemical assay, liquid chromatography (LC) and capillary electrophoresis (CE) do not allow for an accurate identification of asialo-Tf because of its low concentration. Taking into account these premises, this project, starting from an existing capillary electrophoretic method performing “routine” CDT analyses, was aimed at developing an improved procedure suitable for asialo-Tf determination. The “new” CE method was developed by optimizing different experimental parameters such as temperature, electrical potentials, injection time and types, stacking procedures and the running buffer composition. The selected conditions have been 28 °C of temperature and 30 kV of applied voltage combined with the increase of the amount of the loaded material by increasing the injection time up to 50 s and with the use of an optimized running buffer adjusted to the 1,4-diaminobutane (DAB) 9 mM concentration. In addition, a sample pre-treatment procedure with polyethylene glycol 8000 (PEG 8000) at final concentration of 20% was introduced to further improve the asialo-Tf detection through the precipitation of interfering proteins present in the serum sample. The analysis of results showed an additional peak, in both disialo-Tf “positive” and “negative” samples, with the relative migration time (T_mr) ascribable to asialo-Tf and quantifiable up to minimal concentration of 0.2%. The resolution (R) between other isoforms was maintained (R=1.5 between disialo- and trisialo-Tf) with an increase of signal intensity of two times in respected to the results obtained using the “traditional” method. The intra-day reproducibility study of asialo-Tf showed a coefficient of variation (CV) of 23%, for concentrations of asialo-Tf ≤ 0.2% and a CV of 7%, for concentrations ≥ 0.7%. The inter-days reproducibility was characterized by a CV range from 22.5% (for an asialo-Tf concentration of 0.21%) to 5% (for an asialo-Tf concentration of 1.23%). These results can be considered acceptable taking into account the instrumental sensitivity of CE. Although a final validation is still lacking (e.g. by applying immunoextraction and/or immunosubtraction test), at the present stage of the work, we can state that for the first time in the literature a method suitable for the detection and quantification of asialo-Tf in human serum has been developed and preliminarily validated
Application of capillary electrophoresis to analyze human transferrin focusing on the detection and quantification of the asialo-Tf isoform
No full textIn forensic sciences, the analysis of Carbohydrate-deficient transferrin (CDT) is used in the diagnostics of alcohol abuse, because it is known that the concentration of CDT increases after alcohol consumption. The human Transferrin (Tf) is the iron transport serum glycoprotein characterized by oligosaccharide chains that can be n-“antennary” (from zero to four) each one with a sialic-acid residue. Consequently, there are different isoforms with different numbers of sialic-acid residues and CDT includes the monosialo-, the asialo-, and the disialo-Tf isoforms characterized by absence, one or two sialic-acid residues. Currently, CDT analyses are based on the relative quantification of disialo-Tf isoform in respect to the total Tf isoforms identified (up to pentasialo-Tf). At present, the available analytical methods to perform CDT analysis based on immunochemical assay, liquid chromatography (LC) and capillary electrophoresis (CE) do not allow for an accurate identification of asialo-Tf because of its low
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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