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Research Article Antibacterial Effects and Mode of Action of Selected Essential Oils Components against Escherichia coli and Staphylococcus aureus
Get PDFCopyright © 2015 Julio Cesar Lopez-Romero et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Bacterial resistance has been increasingly reported worldwide and is one of themajor causes of failure in the treatment of infectious diseases. Natural-based products, including plant secondary metabolites (phytochemicals), may be used to surpass or reduce this problem. The objective of this study was to determine the antibacterial effect and mode of action of selected essential oils (EOs) components: carveol, carvone, citronellol, and citronellal, against Escherichia coli and Staphylococcus aureus. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were assessed for the selected EOs components. Moreover, physicochemical bacterial surface characterization, bacterial surface charge, membrane integrity, an
Potencial antioxidante de laurel (litsea glaucescens) y su aplicación en un modelo cárnico
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Litsea glaucescens (LG) es una planta endémica de México, que es utilizada como especia y para el tratamiento de diversos padecimientos en medicina tradicional. Existen pocos reportes acerca de su potencial biológico y composición de compuestos fenólicos, y cómo ésta puede ser afectada por la temporalidad. Se desconoce también el potencial efecto de LG como aditivo alimentario. El objetivo de esta investigación fue purificar y caracterizar los compuestos bioactivos que determinan el potencial biológico de LG. Así como también, evaluar el efecto de la temporalidad sobre el potencial biológico y perfil de compuestos fenólicos de LG, y evaluar su efecto como aditivo en carne fresca de cerdo. Se elaboró un extracto metanólico de LG (EMLG),el cual fue sometido a cromatografía en columna (CC) logrando obtener dos fracciones (F-XI y F-XII) con elevada actividad antioxidante (AA) y contenido de compuestos fenólicos (CF). Las dos fracciones nuevamente fueron sometidas a CC, permitiendo obtener tres compuestos. Los resultados de RMN (1H y 13C), HPLC-ESI-MS y HPLC-DAD mostraron que los compuestos purificados correspondían a epicatequina, quercetrina y kaempferol. Posteriormente, se elaboraron EMLG de las diferentes épocas del año: otoño (ALGE) e invierno (WLGE) de 2015 y primavera (SLGE) y verano (SULGE) de 2016. Los resultados mostraron que los EMLG poseen alto contenido de compuestos fenólicos (CF) (92.9-138.2 mg EAG/g m.s.) y elevada actividad antioxidante (AA) a través de los distintos métodos evaluados (DPPH IC50=14.7-27.2 μg/mL, FRAP=1466.4-2614.3 μM Fe (II)/g m.s. y ORAC=3413.3-3700 μM ET/g m.s.). A su vez, se observó que la temporalidad tiene un efecto sobre el contenido de CF y AA, donde ALGE y SULGE fueron los que presentaron mayor potencial (P<0.05). Posteriormente, se evaluó el efecto de ALGE, F-XI y F-XII como agentes antioxidantes en hamburguesas de cerdo almacenadas en refrigeración (11 días, 4 °C). Los resultados mostraron que los tratamientos evaluados disminuyeron la oxidación lipídica y proteica de las hamburguesas, logrando extender su vida de anaquel (P<0.05) (3 días con respecto al tratamiento control). Además, estos aditivos preservaron el color de las hamburguesas durante un periodo más largo, comparado con el tratamiento control (sin aditivo). Los resultados obtenidos evidenciaron que la temporalidad afectó las actividades biológicas de los EMLG, y que su elevado potencial biológico está relacionado con el contenido de CF
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
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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