1,720,956 research outputs found
Hydrodistillation kinetic and biological investigations of essential oils from the Tunisiam Crithmum maritimum L.
No full textThis work describes the study of the chemical composition and bioactivity of the essential oils of Crithmum maritimum and the location of dillapiole one of their major and bioactive constituents. This compound was detected at increasing percentages in all the collected fractions during the extraction process. The highest percentage of dillapiole was obtained in the last fraction (F9) with 100% in the roots. The essentials oils of roots and aerial parts and F9 were assayed for their antiradical and enzymatic antioxidant properties (Catalase and Paraoxonase), the results showed that F9 and the roots essential oil improve the activity of Catalase and Paraoxonase, respectively. The isolated oils and F9 were tested against five bacteria and four candida species. The oil roots exhibited significant activity towards Staphylococcus aureus and Enterococcus faecalis. Dillapiole was found to be the strongest anticandidal. The cytotoxic activity of essential oils and F9 was evaluated against Hela and A549 cancer cell lines. F9 exhibited the best cytotoxic effect against Hela cell line. These results may suggest that C. maritimum essential oils can be used as a good source of dillapiole which could be used as a natural preservative ingredient in food and/or for pharmaceutical preparations
Fractional hydrodistillation and biological evaluation of essential oils from Crithmum maritimum L.
No full textIn some previous studies, it has been demonstrated that the final composition of the essential oils can be influenced by
the distillation time and some biological activities increased according to the proportion of some types of compounds such
as monoterpene alcohols and phenolic derivatives contained in the tested essential oil fractions (1).
The aim of the present study was particularly the identification of the bioactive principles of the essential oils from the
aerial parts and the roots of Crithmum maritimuL. (2) during their fractional extraction by hydrodistillation. The antioxidant,
antibacterial and cytotoxic activities of the essential oils and their collected fractions were also studied.
Our results showed that the main constituent of the oils was dillapiole, detected at increasing percentages (67.7-100%)
in all the collected fractions during the extraction process. The antioxidant features of all the isolated fractions (F1-F9) of the two oils were also evaluated using DPPH, ABTS, reducing power and paraoxonase assays. The results showed that the IC50
(DPPH) of F9 (aerial parts and roots) were 0.042 ± 0.001 mg/mL and 0.038 ± 0.001 mg/mL, respectively. Moreover, the oil
roots exhibited strong growth suppression particularly against Staphylococcus aureus and Enterococcus faecalis. The fraction
F9, the aerial parts and the roots essential oils were also tested for their cytotoxic activity and interesting results were noted
Aroma volatile components, fatty acids and antibacterial activity of four Tunisian Punica granatum L. flower cultivars
No full textThis study investigates the varietal effects on volatile components and fatty acids composition (analysed by GC–MS and GC, respectively) as well as the antibacterial propriety (using microdilution test) from four Tunisian pomegranate flower cultivars (Tounsi, Nabli, Gabsi and Chelfi). The Chelfi flowers seemed to be the richest in terpenoids (28.39%), aldehydes (13.24%) and alcohols (22.30%). Those volatiles seemed to be the most important groups with apparent difference between varieties. Fatty acid profiles varied significantly among cultivars. The most abundant saturated fatty acid was palmitic acid where Nabli cultivar exhibited the highest amount (435.80 μg/g). However, Gabsi cultivar had the highest content of unsaturated fatty acids where the linolenic acid and linoleic acid were the most frequent polyunsaturated fatty acids with 254.42 and 707.73 μg/g, respectively. Results presented here may suggest that the volatiles fraction of the studied cultivars possess antimicrobial activities. This work gives further knowledge for extensive development of this medicinal plan
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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
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