1,720,954 research outputs found
Effect of Ethanol on Human Colon Carcinoma CaCo‐2 and HT‐29 Cell Lines during the Maturation Process
No full textThe aim of the study was to ascertain whether the exposure to ethanol of human colon carcinoma CaCo‐2 and HT‐29 cell lines affects the differentiation process. As an index of enterocytic differentiation, the expression of sucrase, alkaline phosphatase, α2,6‐sialyltransferase toward the N‐acetyllactosaminic sequence, and β1,4‐N‐acetylgalactosaminyltransferase (β1,4GalNAc‐transferase) was examined. The latter enzyme is responsible for the biosynthesis of Sd* carbohydrate histo‐blood antigen, which mainly occurs in human colonic cells; its expression in CaCo‐2 cells depends strictly on the enterocytic differentiation. The addition of ethanol in the culture medium resulted in a significant increment of sucrase and α2,6‐sialyltransferase activities in both cell lines, as well as theβ1,4GalNAc‐transferase activity in CaCo‐2 cells and alkaline phosphatase activity in HT‐29 cells. The increment was dose‐dependent in the range between 50 and 200 mm ethanol and evident after 2 days of exposure in both cell systems. These results support the notion that, as occurs for cell lines of different origin, the ethanol in vitro positively affects the differentiation of intestinal cells, namely along the enterocytic lineage. The putative mechanism by which ethanol interferes with the maturation process of colonic cells is discussed. Copyright © 1994, Wiley Blackwell. All rights reserve
Effect of Acute and Chronic Ethanol Administration on Rat Liver α 2,6‐Sialyltransferase Activity Responsible for Sialylation of Serum Transferrin
No full textThe effect of a single administration and a 6‐week treatment with ethanol on rat liver sialyltransferase activity towards asialoglycoproteins and N‐acetyllactosamine (Galβ91,4GlcNAc) was studied. Since only the cα2,6‐sialyltransferase is involved in the in vivo sialylation of transferrin, GalβS1,4GlcNAc was chosen as an acceptor and α2,6‐sialyl‐N‐acetyllactosamine was separated from the corresponding α2,3‐sialyl isomer present in the sialyltransferase reaction mixture by high‐performance liquid chromatography. After a single ethanol administration there was a low (about 20%) but significant (p < 0.005) reduction of sialyltransferase activity towards asialotransferrin as well as a reduced α2,6‐sialyltransferase activity towards N‐acetyllactosamine. An opposite result was found in the chronically ethanol‐treated rats: in these animals either the total or α2,6‐sialyl‐transferase activity was slightly higher than in control animals. Blood ethanol concentration was significantly high (3.3 ±1.2 mg/ml) only in the acute‐treated animals, suggesting that the accumulation in the body of ethanol and/or its metabolites induces a reduction of liver α2,6‐sialyltransferase activity responsible for the transferrin sialylation. Current results are consistent with the finding (Stibler H, Hultcrantz R: Alcohol Clin Exp Res 11:468–473, 1987) that an enhanced level of hyposialylated transferrin isoforms is a marker of present but not previous alcohol abuse. Copyright © 1989, Wiley Blackwell. All rights reserve
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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