1,720,964 research outputs found
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
Effetcs of simvastatin on liver and plasma levels of cholesterol, dolichol and ubiquinol in hypercholesterolemic rats
No full textPlasma advanced glycosylation end products in maintenance haemodialysis patients
No full textPentosidine is a useful marker of advanced glycation end-products (AGE) which form cross-links between proteins and have been found elevated in plasma and tissues of uraemic and haemodialysed subjects. The origin and fate of these molecules are not clearly understood, but they might play a role in the cardiovascular complications of end stage renal failure. The aim of this study was to evaluate the effect of different types of substitutive therapy on the removal of pentosidine. Methods. Pentosidine was measured by a two-step HPLC methodology. Its concentration was evaluated in plasma before and after dialysis session, in 24-h urine, and in dialysate of subjects treated with three types of chronic substitutive therapy: bicarbonate haemodialysis, acetate-free biofiltration, and haemofiltration. Pentosidine levels were compared among the three therapy modalities and correlated with clinical and biochemical parameters. Results. Plasma pentosidine level was extremely high (23.7 ± 2.0 pmol/mg protein) in the patients treated with the different dialysis modalities. The dialysis session had no significant effect on its plasma concentration, but haemofiltration seemed to be the most efficient method (300-2000 nmol of pentosidine removed per session versus 250-700 nmol per session with the two other approaches). An interesting correlation was found between pentosidine and blood urea nitrogen (r = 0.58, P < 0.01) and pentosidine with uric acid (r = 0.48, P < 0.05). Conclusions. These results suggest that none of the methodology showed a good removal of pentosidine, but among them haemofiltration has the best efficiency. The statistical relationships between pentosidine and urea and uric acid respectively might provide insight into the origin of pentosidine. The accumulation of reactive AGE in uraemic patients may be implicated in the organ and tissue damage observed in uraemia
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
1,1,2,2-tetrachloroethane-induced early decrease of dolichol levels in rat liver microsomes and Golgi apparatus.
No full textIs amyloid beta-protein glycated in Alzheimer disease?
No full textRecent data suggest that protein glycation is involved in the process of amyloid formation in Alzheimer's disease (AD). To further investigate this issue, we analyzed the presence of advanced glycation end products (AGE) in soluble and insoluble forms of amyloid β-protein (βP) as well as in apolipoprotein E (apoE), a protein bound to amyloid deposits. Both proteins were extracted from cerebral cortex obtained from patients with AD and probed by immunoblotting with two antibodies specific for different AGE, already known to immunocytochemically label amyloid plaques. All the AGE antibodies failed to recognize either βP or apoE, whereas they reacted with synthetic βP glycated in vitro. These findings indicate that other proteins associated with amyloid deposits are candidates to be modified with AGE in Alzheimer's cerebral tissue
Effects of 1,2-dichloroethane intoxication on dolichol levels and glycosyltransferase activities in rat liver microsomes and Golgi apparatus
No full textProtein oxidation in hemodialysis and transplantation.
No full textOxidative damage of plasma proteins determined with the markers carbonyl group (CG) content and thiobarbituric acid-reactive substances (TBARS) was studied in 13 hemodialyzed and eight kidney-transplanted patients. The level of CGs was 38% higher in hemodialysis (HD) patients (1.49 ± 0.05 nmol/mg protein) than in the healthy subjects (1.08 ± 0.03 nmol/mg protein); the TBARS level was also higher in HD patients than in the control group (2.64 ± 0.15 v 1.81 ± 0.09 nmol/mL, P < .001). These data confirm that in end-stage renal failure, an increased oxidative stress is present and is able to induce protein damage. After transplantation, the CG content in protein was reduced (1.34 ± 0.08 nmol/mg protein), but it was not significantly different from the level in the HD group. The failure to return to the normal range suggests that an impaired redox status is maintained, resulting in a sustained elevation of CG. Conversely, the level of TBARS in transplanted patients (1.99 ± 0.22 nmol/mL) was not significantly different from that in the control group (1.81 ± 0.09), suggesting that lipoperoxidation may be inhibited. These results may be explained by the different turnover rates of the molecules and by the distinct origin of the two markers, resulting from the damage of proteins or lipids. Thus, lipoperoxidation would produce rapidly removable molecules, whereas protein oxidation damage would tend to accumulate. However, the significant correlation found between CGs and TBARS indicates that a common cause (oxidative stress) binds the two markers of damage
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