1,720,969 research outputs found
Effects of Losartan and Irbesartan administration on brain angiotensinogen mRNA levels
Full text linkLosartan,
2-n-butyl-4-chloro-5-hydroxymethyl-1-[(2'(1H-tetrazol-5-yl)-biphenil-4-yl)methyl]
imidazole, and Irbesartan,
2-n-butyl-3-[(2'-(1H-tetrazol-5-yl)-biphenyl-4-yl)methyl]-1,3-diaza-spiro[4,4]non
-1-en-4-one, are two angiotensin AT1 receptor antagonists largely used in human
health care as antihypertensive agents. Their ability to cross the blood-brain
barrier and to influence the central renin-angiotensin system are widely
investigated, but how this brain system responds to the subchronic and chronic
block of the angiotensin AT1 receptor is still unknown. Normotensive rats were
intragastrically implanted for 7- and 30-day administration, with a dose of 3 and
30 mg/kg body weight. Treatments were shown to influence, in a dose-, time- and
brain-area-dependent manner, angiotensinogen mRNA levels in scanned areas. This
study showed a general up-regulation of angiotensinogen mRNA expression after 7
days and a widespread down-regulation or basal level of expression after a 30-day
administration of two angiotensin AT1 receptor antagonists
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
Recovery from vanadium involves the elimination of cellular structures in the yeast Hansenula polymorpha
No full textWhole genome sequencing analysis of alpaca suggests TRPV3 as a candidate gene for the suri phenotype
Full text linkBackground: Alpaca is a domestic South American camelid probably arising from the domestication of two wild camelids, the vicugna and the guanaco. Two phenotypes are described for alpaca, known as huacaya and suri. Huacaya fleece is characterized by compact, soft, and highly crimped fibers, while suri fleece is longer, straight, less crimped, and lustrous. The gene variants determining these phenotypes are still unknown, although previous studies suggested a dominant inheritance of the suri. Based on that, the aim of this study was the identification of the gene variants determining alpaca coat phenotypes through whole genome sequencing (WGS) analysis. Results: The sample used includes two test-cross alpaca families, suri × huacaya, which produced two offspring, one with the suri phenotype and one with the huacaya phenotype. The analyzed sample was expanded through the addition of WGS data from six vicugnas and six guanacos; this because we assumed the absence of the gene variants linked to the suri phenotype in these wild species. The analysis of gene variant segregation with the suri phenotype, coupled with the filtering of gene variants present in the wild species, disclosed the presence in all the suri samples of a premature termination codon (PTC) in TRPV3 (transient receptor potential cation channel subfamily V member 3), a gene known to be involved in hair growth and cycling, thermal sensation, cold tolerance and adaptation in several species. Mutations in TRPV3 were previously associated with the alteration of hair structure leading to an impaired formation of the hair canal and the hair shaft in mouse. This PTC in TRPV3, due to a G > T substitution (p.Glu475*), results in a loss of 290 amino acids from the canonical translated protein, plausibly leading to a physiological dysfunction. Conclusion: The present results suggest that the suri phenotype may arise from a TRPV3 gene variant which may explain some of the suri features such as its longer hair fibre with lower number of cuticular scales compared to huacaya
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
The vanadate tolerant yeast Hansenula polymorpha undergoes cellular reorganization during growth in, and recovery from, the presence of vanadate
No full textWhen present at intracellular concentrations above micromolar, vanadate becomes toxic to most organisms. However, the yeast Hansenula polymorpha is able to grow on vanadate concentrations in the millimolar range, showing at the same time modifications in cellular ultrastructure and polyphosphate metabolism. Here, the development of the ultrastructural changes, and of vacuolar and secretory activities, during exponential growth on vanadate and upon a return to vanadate-free conditions was investigated. External invertase secretion was inhibited by vanadate, as shown by a decrease in external invertase activity, an intracellular accumulation of small vesicles and a cytoplasmic accumulation of internal invertase. An aberrant appearance of the cell wall and defects in cellular surface growth, possibly linked to defects in secretion, were also observed. However, inhibition of the secretory pathway was not complete since the activity of another secreted enzyme, exoglucanase, increased in the presence of vanadate. Growth on vanadate was also accompanied by an enhancement of vacuolar proteolysis, as indicated by an increase in carboxypeptidase Y activity. However, these modifications were all reversible upon return to vanadate-free conditions, with the normalization process being complex and involving new and dramatic ultrastructural changes and activation of an autophagic mechanism. This mechanism is involved in the elimination/resorption of the observed vanadate-induced aberrant cell structures and/or sites involved in vanadate accumulation, a necessary prerequisite for restoration of conventional ultrastructure and metabolic function
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