1,720,957 research outputs found
Evaluation of medicinal plants from Morocco as novel source of anti-parasitic agents.
Get PDFLa aparición de la resistencia a los antimicrobianos es un enorme problema de salud pública
que hace urgente el desarrollo de nuevas moléculas bioactivas.
En este contexto, las plantas que supuestamente curan las infecciones cutáneas se seleccionan
entre los herbolarios de la región de Fez-Meknes y las seleccionadas se someten a un fraccionamiento
bioguiado para identificar los compuestos activos frente a Leishmania spp. y Staphylococcus aureus
frecuentemente aislados en este tipo de patología en el área estudiada.
Se enumeran 64 plantas, 15 especies que mostraron un índice de frecuencia de citas alto y una
contribución bibliográfica baja para cada germen objetivo se evalúan por sus propiedades
antimicrobianas. La prueba cualitativa utilizando el ensayo de macrodilución en agar reveló que el
extracto etanólico de Rhamnus alaternus es el más activo contra las cepas de S. aureus, mientras que
el ensayo de microdilución mostró que el extracto etanólico de Inula viscosa es el más activo contra
Leishmania spp ..
El fraccionamiento bioguiado, los análisis espectroscópicos y espectrométricos (RMN, EIMS
y HREIMS) del extracto de Rhamnus alaternus dieron como compuestos activos emodina y
kaempferol. Sin embargo, se encontró que la emodina era la más activa contra las cepas de S. aureus
con valores de CMI de 1,93 y 15,63 μg / ml y CC50> 100 μg/ml, lo que refleja la no toxicidad de este
compuesto.
El fraccionamiento bioguiado del extracto de Inula viscosa a través de múltiples pasos
cromatográficos que involucran gel de sílice y columnas sephadex LH-20, cromatografía plana y
centrífuga preparativa permitió identificar mediante análisis espectroscópicos y de correlación (RMN,
HMBC, HSQC y ROESY) ocho compuestos, entre los cuales cuatro (8-epi-xantatina-1β, 5β-epóxido
e inuloxina A, sakuranetina y taxifolina) fueron las más activas contra las especies objetivo,
Leishmania amazonensis y Leishmania donovani con IC50 entre 9.53 y 86.45 µM para promastigotes,
y entre 0.64 y 6.98 µM para amastigotes. Se evaluó la citotoxicidad de los cuatro compuestos en una
línea celular de macrófagos murinos (J774A.1) y el ensayo fluorimétrico usando el reactivo
AlamarBlue mostró que los compuestos no son tóxicos a la dosis probada. Estos cuatro compuestos
anti-Leishmania también fueron activos contra Trypanosoma cruzi, mientras que Naegleria fowleri fue
susceptible únicamente a la inuloxina A.
El mecanismo de acción de estos cuatro compuestos se ha dilucidado utilizando la viabilidad
celular y kits para la detección de eventos de apoptosis. Los resultados obtenidos mostraron que estos
compuestos indujeron eventos de tipo apoptótico en L. amazonensis, L. donovani, T. cruzi y N. fowleri
por alteración de la permeabilidad de la membrana (kit SYTOX Green), condensación de cromatina
(kit doble Hoechst33342 / PI), disrupción de función mitocondrial (sonda JC-1) y disminución de los
niveles de producción de ATP (CellTiter-Glo) además de la regeneración de ROS (kit CellROX) en L.
amazonensis, T. cruzi y N. fowleri
Pharmacological Effects of Grifolin: Focusing on Anticancer Mechanisms
Get PDFGrifolin is a volatile compound contained in essential oils of several medicinal plants. Several studies show that this substance has been the subject of numerous pharmacological investigations, which have yielded interesting results. Grifolin demonstrated beneficial effects for health via its multiple pharmacological activities. It has anti-microbial properties against bacteria, fungi, and parasites. In addition, grifolin exhibited remarkable anti-cancer effects on different human cancer cells. The anticancer action of this molecule is related to its ability to act at cellular and molecular levels on different checkpoints controlling the signaling pathways of human cancer cell lines. Grifolin can induce apoptosis, cell cycle arrest, autophagy, and senescence in these cells. Despite its major pharmacological properties, grifolin has only been investigated in vitro and in vivo. Therefore, further investigations concerning pharmacodynamic and pharmacokinetic tests are required for any possible pharmaceutical application of this substance. Moreover, toxicological tests and other investigations involving humans as a study model are required to validate the safety and clinical applications of grifolin
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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