1,720,957 research outputs found
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
ANTIOXIDANT AND ANTI-SICKLING ACTIVITY OF EXTRACTS FROM THE STEM AND ROOTS BARKS OF STRYCHNOS INNOCUA (DEL.)
No full textObjective: In Togo Strychnos innocua represents a plant traditionally used to cure sickle cell disease. This study aims to carry out a phytochemical study and evaluate the antioxidant and anti-sickling activity of Strychnos innocua root and stem barks to support its use.
Methods: Hydroethanolic and ethanolic extracts of each plant organ were obtained by maceration. Polyphenol content was determined using the Folin-Ciocalteu’s reagent and the flavonoid content using Aluminium trichloride (AlCl3) method. The anti-sickling activity of hydroethanolic extracts of root and stem barks was tested on SS blood samples from sickle cell patients using the Emmel test. Antioxidant activity was assessed by DPPH and FRAP methods on both the hydroethanolic and ethanolic extracts.
Results: Results indicate that the highest levels of polyphenols were measured in the hydroethanolic extract of the root barks (59.32±1.77 mg GAE/g) and the ethanol extract of the stem barks (98.27±2.44 mg GAE/g). The hydroethanolic extract of the root barks and the ethanolic extract of the stem barks showed high levels of flavonoids. Extracts from both organs significantly reduced falciformation (p<0.001) at a rate of 22% (root) and 35% (stem) compared with the control (94%). In addition, root and stem extracts showed slight antioxidant activity.
Conclusion: Results justify the traditional use of Strychnos innocua roots in treating sickle cell anaemia
Evaluation of the antioxidant properties and metabolomic characterisation of Dichapetalum guineense (D.C.) Keay leaf extracts
No full textInternational audienceDichapetalum guineense (DC.) Keay, also known as Dichapetalum madagascariense, is a woody plant native to sub-Saharan Africa, found mainly in West Africa and Madagascar. The plant is widely used in traditional medicine, where it plays a central role in the traditional pharmacopoeia of Togo and Benin due to its many pharmacological properties, particularly in the treatment of malaria and hypertension [1,2]. Research has been carried out to scientifically validate its traditional uses, in particular by isolating and biologically assessing the compounds present in extracts (acetone and petroleum ether) of roots and stems. To date, the main class of compounds identified and isolated from this plant are the dichapetalines (A to H and M), belonging to the phenylpyranotriterpenoid family [3]. The aim of this study was to evaluate these antioxidant properties and to identify the compounds present in the polar extract of the leaves. The antioxidant activity of the extracts was determined using the DPPH radical scavenging test and the ferric reduction method (FRAP) [4]. In addition, analysis of the hydroethanolic extract by UHPLC-MS/MS was used to identify the metabolites present in the extract. The spectral data obtained were processed using MZmine4, then analysed using the SIRIUS and GNPS platforms to construct molecular networks and annotate the various features [5,6]. The hydroethanolic extract demonstrated antioxidant activity with an IC50 of 553.55 ± 5.77 µg/ml. UHPLCMS/MS analysis of the hydroethanolic extract identified several metabolites, with a total of 190 and 135 features detected in positive and negative mode respectively. Around 158 metabolites were annotated. Of these, several metabolites were annotated using the databases used, including alkaloids, amino acids, triterpenoids and phenolic compounds (flavonoids, cinnamic acid derivatives and polyphenols), the latter of which may be correlated with the antioxidant activities of the extracts. In conclusion, D. guineense leaves are a promising source of bioactive compounds, in particular phenolic compounds and flavonoids with antioxidant properties. [1] Gbeassor M et al., J Ethnopharmacol., 1989, 25(1) :115-118. [2] Gbolade A, J Ethnopharmacol., 2012, 144(1) :1-10. [3] Chama MA et al., Toxicon 2021, 193 :28-37. [4] Brukum MF et al., Int J Pharm Pharm Sci ., 2023, 15(9) :18-23. [5] Kai Dührkop et al., Nat Methods, 16, 2019. [6] Wang et al, Nat Biotechnol., 2016, 34, 828‑37
PHYTOCHEMICAL STUDY AND ANTIOXIDANT, ANTIBACTERIAL AND ANTIDIABETIC ACTIVITIES OF FLACOURTIA INDICA LEAVES EXTRACTS FROM THE TOGOLESE FLORA
No full textObjective: Faced with the devastating effect of diabetes, the search for new natural antidiabetic molecules is an exploratory avenue.
Methods: In this study, the leaves of Flacourtia indica were collected from the Togolese flora, and their antioxidant activity was evaluated using DPPH and FRAP assays, following a phytochemical screening conducted through colorimetric and precipitation reactions. The content of total phenols was determined using Folin-Ciocalteu\u27s reagent and flavonoids by aluminum trichloride. The antibacterial activity of the extracts was evaluated using the method of dilution in agar wells with Muller-Hinton® agar. Additionally, the extracts\u27 antidiabetic effect was evaluated in rats made diabetic by alloxan at a dose of 120 mg/kg. b.w.
Results: The results of our work showed the presence of flavonoids, tannins, anthocyanins, and saponins in the extracts. The best polyphenol and flavonoid contents were measured in the hydroethanolic extract and were 186.46±0.308 mg EqAG/g and 464.14±17.043 mgEqQ/g. ES respectively. The hydroethanolic extract has a higher antioxidant power with an IC50 = 110.22 µg/ml. The reducing powers of the ferric ions were 3706±12.124 and 3777±9.238 µmol/ml, respectively for the hydroethanolic and aqueous extracts. The extracts were active against Staphylococcus aureus and are bacteriostatic. The hydroethanolic extract of the leaves of Flacourtia indica significantly reduced (p = 0.0014) blood glucose levels in diabetic rats.
Conclusion: This plant can therefore be a potential medicine in the treatment of diabetes
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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