1,720,982 research outputs found
Isolation and characterization of dermatan sulfate from various sources
No full textIsolation and characterization of dermatan sulfate from various sources
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
Binding Study of Heparin from Different Sources to Antithrombin by Affinity Capillary Electrophoresis.
No full textHeparin, a highly sulfated polydispersed glycosaminoglycan (GAG), is the most widespread clinical anticoagulant; it binds antithrombin III (AT), a member of serine proteinases superfamily, accelerating its antagonist effect on blood coagulation. The binding interaction with AT is an important aspect of the characterization of physicochemical properties of GAGs. With the aim at profiling several clinical and experimental heparin batches from different sources (porcine, bovine and ovine mucosa), a quantitative ATheparin binding investigation was undertaken by means of Affinity Capillary Electrophoresis (ACE). In dynamic-equilibrium ACE, the electrophoretic mobility of the receptor (AT), analysed in a BGE containing the ligand (the considered GAG), is correlated to ligand concentration and binding constant. In particular, a 20 mM sodium phosphate, pH 7.4 buffer (the BGE) was chosen as the neat medium and the experiments were carried out in a highly hydrophilic poly(vinyl alcohol) coated capillary (effective length 8.5 cm). The applied sample consisted of the receptor AT (0.50 μM) and phenylacetic acid (PAA; 10.0 μM) used as a reference compound. The samples were run in triplicate at each of the studied concentration levels of the ligand (heparin, 1.0 – 10.0 x 10-7 M) supplemented to the BGE. The migration time ratio of PAA to AT was assumed as the chemical response to be correlated to the ligand concentration and the binding constant estimation was based on the application of a nonlinear regression method (rectangular hyperbola). The average analysis time was in the order of 4 min. Under these conditions, 18 heparin samples were analysed and their binding constants (Kd) were found between 13 and 54 nM (SD ≤ ± 1.2; n = 3; coefficient of determination r2 ≥ 0.98) with significant differences depending on the origin. Correlation of the Kd values to in vitro anti-factor Xa and anti-factor IIa potencies was evaluated. Both heparin activities demonstrated to be closely related to Kd, independently from the kind and the source of the sample.
Commercial samples from the same manufacturer showed a certain dispersion around the fitting, but the use of the mean point of the cloud significantly improved the coefficient of determination
Affinity capillary electrophoresis in binding study of antithrombin to heparin from different sources
No full textHeparin, a highly sulfated polydispersed glycosaminoglycan (GAG), is the most widespread clinical anticoagulant; it binds antithrombin III (AT), a member of serine proteinases superfamily, accelerating its antagonist effect on blood coagulation. The binding interaction with AT is an important aspect in characterization of physicochemical properties of GAGs. With the aim at profiling several clinical and experimental heparin batches from different sources (porcine, bovine and ovine mucosa), a quantitative investigation of the binding heparin-AT, was undertaken by means of Affinity Capillary Electrophoresis (ACE). In dynamic-equilibrium ACE, the electrophoretic mobility of the receptor (AT), analyzed in a BGE containing the ligand (the considered GAG), is correlated to ligand concentration and binding constant. In particular, a 20mM sodium phosphate, pH 7.4 buffer (the BGE) was chosen as the neat medium and the experiments were carried out in a highly hydrophilic poly(vinyl alcohol) coated capillary (effective length 8.5 cm). The applied sample, consisting in the receptor AT (0.30 μM) and phenylacetic acid (PAA; 10.0 μM) used as a reference compound, was electrophoresed at each of the studied concentration levels of the ligand (heparin samples, 0.30-10.0 × 10(-7)M; heparan sulfate, 0.35-8.0 × 10(-5)M) supplemented to the BGE. The migration time ratio of PAA to AT was assumed as the chemical response to be correlated to the ligand concentration and the binding constant estimation was based on the application of a nonlinear regression method (rectangular hyperbola). Under these conditions, a number of heparin samples were analyzed and their binding constants (Kd) were found within 14.2 and 56.1 nM (SD ≤ ± 2.0; n=3; coefficient of determination r(2) ≥ 0.96). The good correlation of Kd values to the in-vitro activity (anti-factor Xa and anti-factor IIa), confirmed that the affinity for the target AT is an important feature of heparin samples and could be included among their physico-chemical characteristics
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
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