1,720,954 research outputs found
Characteristics of Oleate Binding to Liver Plasma-Membranes and its Uptake by Isolated Hepatocytes
No full textTo clarify mechanisms of hepatic free fatty acid uptake, [3H]oleate uptake by isolated rat hepatocytes was studied,
using solutions of 150 laM bovine serum albumin at oleate:albumin molar ratios of 0.033-6.7:1. Oleate partitioning
between liver plasma membranes and albumin was also studied, and used to ascertain the membrane binding function
for oleate. The experimental uptake curve was complex, but could be resolved by computer fitting into a sum of two
components, one a saturable and the second a linear function of the unbound oleate concentration. The saturable
component comprises > 90% of total oleate uptake when the oleate:albumin molar ratio is < 2.5, but < 50% when
this ratio is > 5. Membrane binding also consisted of a sum of a saturable and a linear component. By comparison
of the computer-fitted uptake and binding functions, separate rate constants for the transfer into the cell of the
saturably and non-saturably bound oleate were estimated to be 0.7 s -~ and 0.05 s -~, respectively. The former is
compatible with a specific, protein-mediated process. It is 15-times greater than the corresponding rate constant for
transfer of non-saturably bound oleate into the cell, which in turn is similar to reported rates of non-specific 'flip-flop'
of fatty acids across lipid bilayers. The observed kinetics are not consistent with models in which uptake occurs
principally from the albumin-bound pool of oleate, or solely from the oleate which has partitioned passively into the
lipid bilayer of the plasma membrane
Oleate uptake by isolated hepatocytes and the perfused rat liver is competitively inhibited by palmitate
No full textCompetition for uptake between long-chain free fatty acids has been difficult to document, because there has been no algorithm for computing unbound concentrations of two fatty acids simultaneously in solution with albumin. We modified an iterative procedure to permit this computation and studied initial [ 3H]oleate uptake by isolated hepatocytes and steady-state uptake by the single-pass perfused rat liver from 600 μM bovine serum albumin solutions containing various concentrations of oleate in the presence and absence of palmitate. In both systems, the Michaelis-Menten constant was significantly higher in the presence of palmitate than in its absence, whereas the maximal reaction velocity was unaltered, indicating competitive inhibition. In additional experiments employing the multiple transhepatic indicator-dilation technique, the influx rate constant and permeability- surface area product for oleate influx were significantly reduced by palmitate, confirming that the competition observed in the conventional perfused liver studies was at the influx step. Long-chain fatty acid uptake has now been shown to exhibit all the kinetic properties of facilitated transport and cannot be attributed solely to passive diffusion
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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