1,721,010 research outputs found
CELL DEATH AND AUTOPHAGY: CYTOKINES, DRUGS, AND NUTRITIONAL FACTORS
Full text linkCellsmay use multiple pathways to commit suicide. In certain contexts, dying cells generate large amounts
of autophagic vacuoles and clear large proportions of their cytoplasm, before they finally die, as exemplified
by the treatment of human mammary carcinoma cells with the anti-estrogen tamoxifen (TAM,
≤1 M). Protein analysis during autophagic cell death revealed distinct proteins of the nuclear fraction
including GST- and some proteasomal subunit constituents to be affected during autophagic cell death.
Depending on the functional status of caspase-3, MCF-7 cells may switch between autophagic and apoptotic
features of cell death [Fazi, B., Bursch,W., Fimia, G.M., Nardacci R., Piacentini, M., Di Sano, F., Piredda,
L., 2008. Fenretinide induces autophagic cell death in caspase-defective breast cancer cells. Autophagy
4(4), 435–441]. Furthermore, the self-destruction of MCF-7 cells was found to be completed by phagocytosis
of cell residues [Petrovski, G., Zahuczky, G., Katona, K., Vereb, G., Martinet,W., Nemes, Z., Bursch,W.,
Fésüs, L., 2007. Clearance of dying autophagic cells of different origin by professional and non-professional
phagocytes. Cell Death Diff. 14 (6), 1117–1128].
Autophagy also constitutes a cell’s strategy of defense upon cell damage by eliminating damaged bulk
proteins/organelles. This biological condition may be exemplified by the treatment of MCF-7 cells with
a necrogenic TAM-dose (10 M), resulting in the lysis of almost all cells within 24 h. However, a transient
(1 h) challenge of MCF-7 cells with the same dose allowed the recovery of cells involving autophagy.
Enrichment of chaperones in the insoluble cytoplasmic protein fraction indicated the formation of aggresomes,
a potential trigger for autophagy. In a further experimental model HL60 cells were treated with
TAM, causing dose-dependent distinct responses: 1–5 MTAM, autophagy predominant; 7–9 M, apoptosis
predominant; 15 M, necrosis. These phenomena might be attributed to the degree of cell damage
caused by tamoxifen, either by generating ROS, increasing membrane fluidity or forming DNA-adducts.
Finally, autophagy constitutes a cell’s major adaptive (survival) strategy in response to metabolic challenges
such as glucose or amino acid deprivation, or starvation in general. Notably, the role of autophagy
appears not to be restricted to nutrient recycling in order to maintain energy supply of cells and to adapt
cell(organ) size to given physiological needs. For instance, using a newly established hepatoma cell line
HCC-1.2, amino acid and glucose deprivation revealed a pro-apoptotic activity, additive to TGF- 1. The proapoptotic
action of glucose deprivation was antagonized by 2-deoxyglucose, possibly by stabilizing the
mitochondrial membrane involving the action of hexokinase II. These observations suggest that signaling
cascades steering autophagy appear to provide links to those regulating cell number.
Taken together, our data exemplify that a given cell may flexibly respond to type and degree of
(micro)environmental changes or cell death stimuli; a cell’s response may shift gradually from the elimination
of damaged proteins by autophagy and the recovery to autophagic or apoptotic pathways of cell
death, the failure of which eventually may result in necrosis
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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