1,720,957 research outputs found
Aktivitas Sitotoksik Ekstrak Etil Asetat Daun Jati Belanda (Guazuma ulmifolia Lamk.) Terhadap Sel Kanker Leukemia L1210
Full text linkKanker merupakan penyakit yang menyebabkan tingkat kematian paling tinggi di dunia. Sel kanker merupakan sel yang pertumbuhannya tidak terkontrol dan berkembang di dalam jaringan sel tubuh. Kandungan flavonoid dan sifat antioksidan yang tinggi dari daun jati belanda (Guazuma ulmifolia Lamk) dapat digunakan sebagai pengobatan terapi kanker. Penelitian ini dilakukan untuk menentukan aktivitas sitotoksik G. ulmifolia Lamk terhadap sel leukemia L1210. Daun G. ulmifolia kering dimaserasi secara bertahap menggunakan pelarut n-heksana, etil asetat, dan etanol. Masing-masing ekstrak yang diperoleh dievaluasi aktivitas sitotoksisitasnya terhadap sel leukemia L1210. Ekstrak paling aktif difraksinasi menggunakan kromatografi kolom dengan berbagai pelarut yang sesuai. Selanjutnya semua subfraksi yang diperoleh diuji aktivitas sitotoksiknya dan dianalisis dengan kromatografi cair kinerja tinggi (KCKT) untuk mengetahui bentuk kromatogranya. Hasil penelitian menunjukkan bahwa ekstrak etil setat memiliki nilai IC50 paling kecil diantara ekstrak yang lain, yaitu sebesar 6,23 µg/mL. Fraksinasi ekstrak etil asetat diperoleh (1-8) fraksi dengan fraksi 4 memiliki aktivitas paling tinggi yang berpotensi sebagai anti kanker dengan nilai IC50 sebesar 2,67 µg/mL. Analisis fraksi 4 etil asetat G ulmifolia menggunakan KCKT menunjukkan bahwa kandungan utama adalah flavonoid
Cytotoxic Activity Against L1210 Leukemia Cells from the Ethyl Acetate Fraction of Kenikir Leaves (Cosmos. Caudatus) Preserved by Gamma Irradiation
Full text linkKenikir leaves (Cosmos caudatus) Has been used as traditional medicine, especially as an anti-cancer, this plant has been in Indonesia both in herbs and capsules. Microbial contamination of herbal medicinal raw materials occurs when the storage process is done. One of the preservation techniques used in the industry is using gamma irradiation techniques to reduce microbial and fungal contamination. The purpose of this research was to study the effect of gamma irradiation for the preservation of kenikir leaves (C. caudatus) as an anti-cancer based on cytotoxic activity using L1210 leukaemia cells. The simplicia was gamma-irradiated by Co-60 source with variation doses of 0 (control); 5; 7.5; 10; and 15 kGy. Then the irradiated and control samples were macerated successively using n-hexane, ethyl acetate, and ethanol. The active extract (ethyl acetate) was further fractionated using column chromatography, obtained seven fractions (F1 - F7). The seven fractions' cytotoxic activity against L1210 leukaemia cells showed that fraction 3 (F3) was the most active fraction with an IC50 of 1.26 µg/mL. Each dose's F3 cytotoxic activity showed that the IC50 7.5 kGy irradiation sample did not change significantly with control (0 kGy) based on ANOVA analysis using SPSS 24 with a 95% confidence level. In comparison, irradiation samples of 10 and 15 kGy showed a change in the IC50 value is significant with the control (0 kGy). These results indicate that gamma irradiation can be used as an alternative for preserving C. caudatus with a maximum dose of 7.5 kGy, so that its anti-cancer properties do not change with those without irradiation
Gamma Irradiation for Preservation of Suruhan Herbs (Peperomia pellucida L. Kunth.) and its Bioactivity Against L1210 Leukemia Cells
Full text linkPeperomia pellucida includes the Piperaceae family that has anti-cancer, anti-inflammatory, antioxidant, and anti-microbial activities. Microbes easily contaminate dry herbs during storage, so special handling is needed. One of the preservation techniques is using irradiation technology. This technique can be used to extend the shelf life of herbal medicinal ingredients. This research aimed to study the effects of irradiation on the anti-cancer activity of P. pellucida leaves. P. pellucida leaves' dried powder was irradiated at doses of 5, 7.5, 10, and 15 kGy. The anti-cancer activity test was carried out against L1210 leukaemia cells. The un-irradiated irradiated samples were macerated successively with n-hexane, ethyl acetate, and ethanol, then be concentrated. The ethyl acetate extract was fractionated using silica gel column chromatography, obtained seven fractions. Their IC50 values < 20 mg/mL, with fraction F4 was the most active fraction (IC50 1.9 mg/mL). The result showed that gamma radiation at doses of 5 - 15 kGy reduced their cytotoxic activity significantly. However, the fractions were still in the active category as anti-cancer (IC50 values were < 20 mg/mL)
The Effect of Gamma Irradiation on Ethanolic Extract of Temulawak (Curcuma xanthorrhiza Roxb.) Against Human Cancer Cell Lines
Full text linkThe Effect of Gamma Irradiation on Ethanolic Extract of Temulawak (Curcuma xanthorrhiza Roxb.) Against Human Cancer Cell Lines. One of the medicinal plants that are widely used by the people of Indonesia is temulawak (Curcuma xanthorrhiza Roxb.) with the active ingredient is curcuminoid. The curcuminoid is a yellow compound that is believed to have anti-cancer properties, therefore its properties must be maintained in the post-harvest process. This research aimed to study the effect of gamma irradiation on the simplicia of C. xanthorrhiza rhizomes in inhibiting the proliferative activity against human cancer cell lines. The dry powder of C. xanthorrhiza rhizome was irradiated with gamma at a dose of 10 kGy in 2 replications, then extracted using ethanol solvent, evaporated, to obtain an ethanol extract. As a control, an un-irradiated sample was prepared and extracted in the same manner. Each ethanol extract from irradiated and control samples was then tested for their antioxidant activity by DPPH method and antiproliferative activity against human cancer cell lines (HUT78, A549, HeLa, and THP1). The results showed that the ethanol extract of irradiated C. xanthorrhiza rhizome with a dose of 10 kGy still had antioxidant activity and anticancer properties based on the bioassay against four those human cancer cell lines, although the antiproliferative activity decreased between 8-30% compared to the control sample. The highest antiproliferative activity was shown by the ethanol extract against HUT78 cancer cell line with IC50 values of 5.4 and 10.7 µg/ml for control and irradiated samples respectively. Based on the silica gel TLC plate, the ethanolic extracts of C. xanthorrhiza rhizome both unirradiated- and irradiated samples contained curcumin (Rf = 0.58) and demethoxycurcumin (Rf = 0.38)
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
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