1,720,964 research outputs found
Metal binding to Pseudomonas aeruginosa azurin: a kinetic investigation
No full textThe interaction between azurin from Pseudomonas aeruginosa and Ag(I), Cu(II), Hg(II), was investigated as a function of protein state, i.e. apo-, reduced and oxidised azurin. Two different metal binding sites, characterized by two different spectroscopic absorbancies, were detected: one is accessible to Ag(I) and Cu(II) but not to Hg(II); the other one binds Ag(I) and Hg(II) but not copper. When added in stoichiometric amount, Ag(I) shows high affinity for the redox center of apo-azurin, to which it probably binds by the -SH group of Cys112; it can displace Cu(I) from reducedazurin, while it does not bind to the redox center of oxidizedazurin. Kinetic experiments show that Ag(I) binding to the reduced form is four times faster than binding to the ape-form. This result suggests that metal binding requires a conformational rearrangement of the active site of the azurin. Interaction of Ag(I) or Hg(II) ions to the second metal binding site, induces typical changes of UV spectrum and quenching of fluorescence emission
Comparison among plasma-derived clotting factor VIII by using monodimensional gel electrophoresis and mass spectrometry
No full textBackground. Deficiency or dysfunction of coagulation factor VIII (FVIII) is the underlying cause of haemophilia A. Haemophilic patients are at present treated with plasma-derived FVIII (pdFVIII) or recombinant FVIII (rFVIII) in order to correct their clotting deficiency. pdFVIII concentrates are exclusively produced from human plasma upon pooling from multiple donors. It is not know whether the presence of excess of other plasma proteins, in addition to von Willebrand factor, could stimulate untoward immune responses in the recipient. Thus, information regarding the presence of contaminants in commercial products is of concern. Materials and Methods. Two commercially available pdFVIII concentrates were characterized through SDS-PAGE and mass spectrometry Emoclot® and Beriate®. Results. The components of two pdFVIII products considered in this study were well identified by mass spectrometry analysis, in both cases we found abundant components coming from blood plasma, and some other contaminants. Only in Beriate® we also found truncated form of pdFVIII. Conclusion. The two pdFVIII examined showed the presence of vWF, Fibrinogen in excess, and other substances that could be considered as contaminants or impurities. © SIMTI Servizi Srl
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
Resveratrol activity on MCL cell line jeko-1: a proteomic approach
No full textBackground Very few studies have attempted the investigation of mantle cell lymphoma (MCL) by proteomic tools. We studied MCL cell lines using the PhosphoScan approach. We then investigated the importance of the identified pathways for the survival of MCL cell lines using a functional validation approach.Results 421 peptides were identified, corresponding to 341 proteins. The most represented pathways suggest the tonic activation of the B-cell receptor signalling. Inhibition of the upstream molecule SYK by Piceatannol, followed by the reduction of downstream target phosphorylation, caused apoptosis of MCL cells. Immunofluorescence studies showed a compartment transition of P-SYK after inhibition
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
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