1,720,956 research outputs found
Beta-cyclodextrin and permeability to water in the bladder of Bufo arenarum
No full textWe measured the effect of β-cyclodextrin (BCD, a cholesterol scavenger) on water flow across the isolated toad bladder exposed to an osmotic gradient (Jw) by a gravimetric technique. BCD, when present in the solution bathing the apical side of the bladder, inhibited the increase in Jw caused by nystatin, a polyene antibiotic that acts by directly binding apical membrane cholesterol. When present in the basolateral bath, BCD inhibited the increase in Jw caused by basolateral exposure to oxytocin (which binds membrane receptors and stimulates the synthesis of cAMP), but did not alter the response to theophylline (which inhibits hydrolysis of cAMP by cyclic nucleotide phosphodiesterase). The present data are consistent with the notion that agents that increase Jw by interacting with membrane receptors, which appear to be clustered in cholesterol-rich domains of the basolateral membrane, are altered by cholesterol depletion, whereas agents that do not interact with receptors or other basolateral membrane components are not affected by this treatment. In either case, cholesterol depletion of the apical membrane does not affect the increase in Jw brought about by an increase in intracellular cAMP concentration.Fil: Orce, Gabriel Guillermo F.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentina. Universidad Nacional de Tucumán. Facultad de Medicina; ArgentinaFil: Castillo G.. Universidad Nacional de Tucumán. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Chanampa Y.. Universidad Nacional de Tucumán. Facultad de Medicina; Argentin
Effect of mercuric chloride on electrical parameters and anion fluxes in the toad skin
Get PDFThe amphibian skin, widely used for studying the transepithelial passage of electrolytes, exhibits anion pathways relatively specific for Cl-. We studied the effect of HgCl2, 1.0×10-4 M on its electrical parameters and unidirectional anion fluxes. In the presence of Cl-, the transepithelial conductance (G) of the isolated skin of the Bufo arenarum toad increased considerably following exposure to HgCl 2, whereas short-circuit current (SCC)-reflecting transepithelial Na+ transport-underwent only slight stimulation. Following the blockade of Na+ intake by amiloride, 1.0×10-4 M, the removal of Cl- from the solution bathing the epidermal border of the skin brought about a decrease in G, and gave rise to a gradient-induced SCC (SCCg) consistent with transepithelial passage of Cl- along its gradient. Addition of mercaptoethanol, 5.0×10-3 M to the bath containing Hg2+ fully reversed these effects. The increase in G was accompanied by an increase in the unidirectional (epidermal to dermal) fluxes of 36Cl- and 131I-, and a decrease in the passage of 99mTcO4-. These results show the effects of HgCl2 to be similar to those of theophylline, although exhibiting a different selectivity. Our data suggest that anion passage following exposure to HgCl2 is, like that stimulated by theophylline, predominantly if not exclusively transcellular, and does not involve a significant opening of the tight junctions.Fil: Castillo, Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Chanampa, Yolanda. Universidad Nacional de Tucumán. Facultad de Medicina; ArgentinaFil: Orce, Gabriel Guillermo F.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentin
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
O consentimento informado em investigação: um processo e um documento
Get PDFLa investigación en seres humanos requiere en forma inexcusable la obtención del
consentimiento informado de los sujetos participantes en ella. Este consentimiento
implica un proceso de información para permitir al sujeto expresar válidamente la
voluntad de participar en una investigación, habitualmente firmando un documento
escrito (el Documento de Consentimiento Informado, DCI) en el que se encuentran
plasmados el proceso de información y el acuerdo del sujeto por medio de una firma. En este trabajo describimos brevemente los principales pasos del ese proceso, y analizamos algunos de los errores más frecuentes del proceso de consentimiento observados por el Comité de Bioética de la Facultad de Medicina de la Universidad Nacional de Tucumán. En la medida en que se mejore la redacción de los DCI y los procedimientos para obtenerlos, los sujetos de investigación estarán mejor protegidos y los tiempos de evaluación serán menores, en beneficio de todos los involucrados y de la sociedad.The use of human subjects in medical research requires inexcusably their consent to
participate after receiving information provided by the researcher that allows them to
make a valid decision. The process involved results in both the investigator and the
research subject signing a document (the Informed Consent Document, ICD) certifying the validity of the information and the subject’s agreement to participate. The present work briefly describes the steps followed to complete this process, and some of the most frequent errors encountered in ICDs included in projects that were evaluated by the Bioethical Committee of the School of Medicine of the National University of Tucumán. As the quality of both the information process and the drafting of the ICD improve, the safety of the research subjects will improve and the evaluation times will decrease, to the benefit of all involved and of the society at large.Fil: Llobeta, Bartolomé. Universidad Nacional de Tucumán. Facultad de Medicina. Departamento Biomédico; ArgentinaFil: Castillo, Graciela Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Orce, Gabriel Guillermo F.. Universidad Nacional de Tucumán. Facultad de Medicina. Departamento Biomédico; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentin
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
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