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AKTIVITAS PENANGKAPAN RADIKAL BEBAS DAN POTENSI ANTIHIPERGLIKEMIK BEBERAPA GAMBIR DARI BEBERAPA PASAR INDONESIA
No full textGambier (uncaria gambier) is known to have antioxidant properties and some studies attributed to the presence of polyphenols. The objective of this study was to investigate the potential of various gambier available in Indonesian market as free radical scavenger and to evaluate its antihyperglycemic potency as α-glucosidase inhibator. Isolation of catechin was carried out by extraction with distilled ethyl acetate as solvent. Analysis of catechin in the gambier dried extracts were carried out by TLC method. The molecular weight and catechin content of gambier dried extracts were determined by analyzing mass spectra and spectrophotometry, respectively. The free radical scavenging aactivity ofextracts were measured by using 1, 1-diphenyl1-2-picrylhydrazyl (DPPH) as stable free radical compound. The antihyperglycemic potency of gambier dried extracts were asseyed, as α-glucosidase inhibator. The results showed that various gambier available in the market were very active as antioxidant, indicated by the IC50 vvalues of gambier dried extracts were 4.6 to 18.2 µg/mL. Whilst th IC50 for glucosidase inhibition varies from 40.45 to 52.43 µg/mL, and classified as a moderate antidiabetic.Gambir (Uncaria gambier) telah diketahui mempunyai aktivitas antioksidan karena mengandung polifenol. Penelitian ini bertujuan untuk mengetahui aktivitas penangkapan radikal bebas dan potensi antihiperglikemik sebagai inhibator α-glukosidase dari gambir yang dikoleksi dari beberapa pasar Indonesia. Isolasi katekin dilakukan dengan cara ekstraksi dengan menggunakan pelarut etil asetat. Analisis awal katekin yang terkandung dalam ektrak kering gambir dilakukan dengan KLT. Evaluasi berat molekul dan kandungan katekin pada ekstrak kering gambir dilakukan masing-masing dengan spektroskopi massa dan spektrofotometer. Aktivitas penangkapan radikal bebas diukur dengan menggunakan 1, 1-difenil-2-pikrilhidrazil (DPPH) sebagai sumber radikal bebas. Potensi antihiperglikemik ekstrak kering gambir dianalisis sebaga inhibator α-glukosidase. Hasil penelitian menunjukan bahwa beberapa gambir yang ada di pasar Indonesia sangat aktif sebagai antioksidan, yang ditunjukkan dengan nilai IC50 dari 4,6 sampai 18,2 µg/mL. Nilai IC50 untuk inhibisi α-glukosidase bervariasi antara 40,45 sampai 52,43 µg/mL, dan diklasifikasikan sebagai antioksidan moderat
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
PENGARUH KONSENTRASI KATALIS DAN PERBANDINGAN MOLARITAS REAKTAN PADA SINTESIS SENYAWA α-MONOLAURIN
Get PDFIn the laboratory scale, the effect of the concentration of H2SO4 catalyst (1.25-6.25) (% w/w) and the equivalent mol ratio between lauric acid and glycerol (1:1; 1:2.5; 2.5:1) on the synthesis of α-monolaurin has been studied. The α-monolaurin compound has been synthesized from lauric acid and glycerol was done by batch esterification on the free solvent system. The esterification by using 5% H2SO4 catalyst and equivalent mol ratio between lauric acid and glycerol 1:2.5 produced most monolaurin, and dilaurin in amount of 31.14 and 4.42%, respectively. The monolaurin and dilaurin are identified by thin layer chromatography (TLC), infrared spectrophotometer (FTIR), liquid chromatography-mass spectrometer (LC-MS), and Nuclear Magnetic Resonance (NMR) spectrometer. The spectral data of monolaurin was compared to spectral data of standard α-monolauri
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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