1,720,998 research outputs found
An elastolytic proteinase from rabbit leukocytes: purification and partial characterization
No full textA proteinase with elastolytic activity was isolated from granules of rabbit bloodstream leukocytes, and purified to apparent homogeneity by a multi-step procedure consisting of ammonium sulfate precipitation, batch fractionation on DEAE-Sephadex A-50, and finally by preparative isoelectric focusing (IEF) on Sephadex G-75 Superfine. The molecule weight of the enzyme, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), was 28,500. This enzyme shows an isoelectric point at pH 9.0. The proteinase is active against natural elastins as well as toward Suc-(Ala)3-NA, Methoxy-Suc-(Ala)2-Pro-Val-NA, and (to a lesser extent) against Suc-(Ala)2-Pro-Leu-NA and Boc-Ala-ONp. The inhibition profile of the isolated enzyme indicates that rabbit granulocyte elastase belongs to the group of serine proteinases. Inhibition by some natural proteinase inhibitors is also observed. Unlike other mammalian elastases, it is insensitive to elastatinal
Iron mobilization from crocidolite as enhancer of collagen content in rat lung fibroblasts
No full textAsbestos exposure causes pulmonary fibrosis by mechanisms that remain uncertain. There is increasing evidence that iron from asbestos is responsible for many of its effects. In this paper, we investigated the effect of iron mobilized from crocidolite asbestos on collagen content in rat lung fibroblast cultures under serum-free conditions. Crocidolite (2, 4, 6 microg/cm2 well) increased collagen content in a dose-dependent manner (+42 +/- 8, +92 +/- 10, and +129 +/- 13% vs controls). This effect was specific for collagen, since it did not alter total protein content and was inhibited by the iron chelator deferoxamine (DFO). Preincubation of crocidolite with citrate (1 mM) for 48 hr resulted in iron mobilization (51 microM) and increased collagen production (>3-fold) in treated cells. These effects occurred without the intervention of serum factors. The absence of cell damage, proliferation or lipid peroxidation leads to the supposition that iron from crocidolite per se may act as a profibrogenic agent. Although the in vivo participation of other cells and factors cannot be excluded, we conclude that iron released from crocidolite plays a role in collagen increase occurring during asbestosis
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
Intermediale Missverständnisse. Franz Fühmann, die Tradition der Operette und das schiefe E.T.A. Hoffmann-Bild in der Spät-DDR
No full textIl contributo studia la ricezione critica delle opere di E.T.A. Hoffmann nella Repubblica Democratica Tedesca degli anni Settanta attraverso l'analisi dei contributi sull'argomento pubblicati da Franz Fühmann. Una serie di rielaborazioni intermediali e multimediali dei testi hoffmanniani nel medium della musica, specie dell'operetta, contribuì a creare e/o consolidare numerosi fraintendimenti sul valore dell'opera di Hoffmann, fornendo la base per interpretazioni fallaci e tendenziose, motivate non da ultimo da ragioni di natura politica
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
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