1,720,961 research outputs found
Mode of action for gastroprotective activity of Muntingia calabura L. leaves in rats
Get PDFGastric ulcer is one of the most common gastrointestinal disorders. As current
antiulcer treatments are associated with wide range of side effects, there is a
need to discover an effective and safer new antiulcer agent. Muntingia calabura
L. (family Muntingiaceae), known as Jamaican cherry or kerukup siam has
been employed traditionally to treat various ailments including gastrointestinal
disorders. The traditional use of M. calabura and its potential antioxidant
properties lead to the present research with the hope of finding an effective
gastroprotective agent. The present study aimed to investigate the antiulcer
activity of M. calabura methanolic leaves extract (MEMC) and its fractions
using rat models, determine the underlying mechanism(s) of action and identify
the phytochemical constituents present in the plant. Acute toxicity study was
conducted using a single oral dose of 2000 mg/kg MEMC. The antiulcer activity
of MEMC was evaluated in ethanol- and indomethacin-induced gastric ulcer rat
models. The rats were administered 8% Tween 80, 100 mg/kg ranitidine, and
MEMC (doses 25-500 mg/kg) orally for seven days, followed by ulcer induction
using absolute ethanol (5 mL/kg) or indomethacin (100 mg/kg). The rats were
euthanized; macroscopic and histological observations of the stomach were
done. Fractionation of MEMC yielded petroleum ether (PEF), ethyl acetate
(EAF) and aqueous (AQF) fractions. Their antiulcer property was investigated
using ethanol-induced gastric ulceration as described above. MEMC and its
fractions were subjected to antioxidant and anti-inflammatory studies including
superoxide and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging,
oxygen radical absorbance capacity (ORAC), total phenolic content (TPC),
inhibition of nitric oxide (NO), lipoxygenase (LOX) and xanthine oxidase (XO)
activity. Evaluation of gastric content and quantification of mucus were carried
out in pylorus-ligated model. Possible involvement of endogenous NO and
sulfhydryl (SH) compounds was determined in animals pre-treated with NGnitro-
L-arginine methyl esters (L-NAME) or N-ethylmaleimide (NEM) prior to
MEMC or EAF treatment. Superoxide dismutase (SOD), gluthathione (GSH),
catalase (CAT), malondialdehyde (MDA), prostaglandin E2 (PGE2) and NO level in the stomach tissue homogenate treated with EAF was determined.
Phytochemical screening and High Performance Liquid Chromatography
(HPLC) analysis was conducted on MEMC, PEF and EAF. EAF was further
subjected to Ultra-high-Performance Liquid Chromatography-Electrospray
Ionization (UHPLC-ESI) analysis. The LD50 of MEMC was >2000 mg/kg.
MEMC exerted significant (p<0.001) gastroprotection in both the ulcer models.
PEF and EAF significantly (p<0.001) attenuated the ethanol-induced gastric
lesions. MEMC and its fractions showed high antioxidant and anti-inflammatory
activities. MEMC and EAF significantly (p<0.01) reduced volume of gastric
content and increased the mucus production. Pre-treatment with L-NAME or
NEM reversed the gastroprotection of MEMC and EAF. EAF markedly
ameliorated the SOD, GSH, CAT, PGE2 and NO level while reducing MDA
level. HPLC profiling showed the presence of quercetin and gallic acid in
MEMC, PEF and EAF. UHPLC-ESI confirmed the presence of these
compounds in EAF. In conclusion, MEMC and EAF exert significant antiulcer
activity. The underlying gastroprotective mechanisms of MEMC and EAF could
be associated with the antioxidant, anti-inflammatory, antisecretory,
participation of mucus, antiperoxidative, modulation of NO and SH compounds
and presence of flavonoids and phenols
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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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