1,720,961 research outputs found
Desarrollo y validación de un método analítico por cromatografía de líquidos de alta eficiencia para la cuantificación de citroflavonoides en plasma de roedor
No full text"En el presente trabajo se llevó a cabo el desarrollo y validación de un método por CLAE para la cuantificación simultánea de cinco flavonoides (naringina, naringenina, hesperidina, rutina y quercetina) en plasma de roedor, esto con la finalidad de establecer los parámetros farmacocinéticos de dichos metabolitos y comprender los procesos metabólicos que proceden a su absorción. Para el desarrollo del método cromatográfico se utilizó un equipo CLAE marca Agilent Technologies 1200 Series (San José, CA, EUA) equipado con detector de arreglo de diodos e inyector automático. Se utilizó como fase estacionaria una columna Phase Sep Spherisorb de C18, con dimensiones de 250 mm de longitud x 4.6 mm de diámetro interno y un tamaño de partícula de 5 µm; la fase móvil consistió en H3PO4 al 1% (A), metanol (B) y Acetonitrilo (C); con un flujo de 1.3 mL/min; además, se empleó un sistema de disolventes en condiciones de gradiente. El volumen de inyección fue de 10 μL, y la temperatura del termostato fue de 30 °C, con un tiempo de post corrida de 5 minutos.
Para llevar a cabo la detección de los flavonoides se seleccionaron 3 longitudes de onda, 256, 284 y 370 nm. Para la optimización del método de extracción en fase sólida, se utilizó un diseño de Box-Behnken con el que se determinó que el pH del buffer empleado juega un papel importante en el proceso de extracción, siendo el pH de 3.19 el óptimo para llevar a cabo este proceso. La validación del método analítico se llevó a cabo de acuerdo a los lineamientos de la AOAC, resultando un coeficiente de correlación lineal mayor a 0.99 en un rango de trabajo entre 0.5 a 7.5 μg/mL. Los LD y LC del método fueron hallados entre 0.02 a 0.10
µg/mL y entre 0.04 a 0.19 µg/mL respectivamente. El porcentaje de recuperación total del método fue de 95.78 ± 1.55 %, mientras que la precisión intradía de éste fue de 2.28 ± 1.34 %, lo que demostró que e
Functional relaxant effect of 6,7-dipropoxy-2H-chromen-2-one is mainly by calcium channel blockade in ex vivo assay of tracheal rings
No full textPharmacological and toxicological study of a traditional mayan herbal preparation used as antihypertensive agent
No full textToxicological Screening of Four Bioactive Citroflavonoids: In Vitro, In Vivo, and In Silico Approaches
No full textAirway smooth muscle relaxant activity of Cordia dodecandra A. DC. mainly T by cAMP increase and calcium channel blockade
No full textInhibitory effect of peptide fractions derivatives from chia (Salvia hispanica) hydrolysis against α-amylase and α-glucosidase enzymes
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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
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