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Efektivitas model pembelajaran problem solving pada materi larutan penyangga dan hidrolisis dalam meningkatkan ketrampilan observasi dan interpretasi [Skripsi]
No full textBib. hal. 41 CD-ROMiii, 41 hlm. : il. ; 30 cm. . -- Lamp. (138 lemba
GEOGRAPHYCAL EFFECT ON THE CYTOTOXIC ACTIVITY OF Annona muricata L. LEAVES ETHANOL EXTRACT AGAINST MCF-7 CANCER CELL
Full text linkMany studies have shown the anti-cancer activities of the chemical compounds extracted from the leaves of Annona muricata or soursop plant. Cianjur and Sukabumi are quite large soursop producing area in Indonesia. This study was carried out to determine the difference of cytotoxic activity of soursop leaves ethanolic extract which were harvested from three different areas of Cianjur (I, II, III) and Sukabumi (I, II, III). The Soursop leaves were macerated with 70% ethanol using microwave assisted extraction (MAE) method. The extract was tested in vitro on breast cancer cell line MCF7 and its constituent was identified using GC-MS apparatus. The results showed that the highest cytotoxic activity with IC50 values of 9.12 µg ml-1 was determined on the extract of soursop leaves harvested from Cianjur III area. Qualitative identification of chemical constituent shows that the soursop leaves contain alkaloid, flavonoid, triterpenoid, tannin and saponin compounds. No steroid compound was detected in the extract. It can be concluded that the geographical regions affected the biochemical properties of soursop leaves
IDENTIFIKASI SENYAWA AKTIF EKSTRAK DAUN CENGKEH (Syzygium aromaticum) SEBAGAI INHIBITOR Streptococcus mutans
Full text linkAbstrakKaries gigi adalah penyakit yang umum dialami oleh masyarakat yang terjadi karena buruknya kebersihan mulut. Kebiasaan masyarakat yang kurang menjaga kebersihan mulut mengakibatkan terbentuknya plak. Plak pada gigi terbentuk karena aktivitas dari berbagai macam mikroorganisme di mulut. Mikroorganisme yang diketahui terlibat dalam pembentukan karies gigi adalah Streptococcus mutans. Salah satu bahan alternatif sebagai antibakteri adalah daun cengkeh. Penelitian ini bertujuan untuk mengidentifikasi senyawa bioaktif daun cengkeh dan mengetahui mekanisme aksinya dalam menghambat pertumbuhan Streptococcus mutans. Daun cengkeh (Syzygium aromaticum) yang digunakan dalam penelitian ini dimaserasi menggunakan metanol 96%. Pengujian aktivitas antibakteri dilakukan dengan metode difusi agar, senyawa bioaktif diidentifikasi menggunakan gas chromatography mass spectrometry dan perubahan membran sel bakteri diamati dengan scanning electron microscopy. Hasil penelitian menunjukkan ekstrak metanol daun cengkeh memiliki aktivitas penghambatan terhadap pertumbuhan bakteri Streptococcus mutans dengan zona hambat sebesar ±32 mm serta nilai konsentrasi hambat minimum (KHM) 20% ekstrak. Mekanisme aksi penghambatan ekstrak daun cengkeh terhadap pertumbuhan bakteri diduga dengan membuat lubang pada membran sel bakteri. Hasil penelitian ini juga menunjukkan bahwa daun cengkeh memiliki kandungan senyawa bioaktif 3-allyl-6-methoxyphenol-eugenol, caryophyllene 1,4,7,-cycloundecatriene, 1,5,9,9-tetramethyl, phenol, 2-methoxy-4-(2-propenyl), dan eugenol acetate yang dapat menjadi kandidat penghasil senyawa aktif untuk mengatasi karies gigi.Abstract Dental caries is a common disease experienced by people who do not maintain oral hygiene. Habits of not maintain oral hygiene result in the formation of plaque. The microorganism known to be involved in the formation of dental caries is Streptococcus mutans. Plants that have antibacterial properties, such as clove (Syzygium aromaticum) leaf, can be an alternative for carrying this problem. This study aims to identify the bioactive compounds of clove leaves and to determine the mechanism of its action in inhibiting the growth of Streptococcus mutans. Clove leaves were macerated using 96% methanol for the extraction. Antibacterial activity was examined by agar diffusion method, bioactive compounds were identified using gas chromatography mass spectrometry, and bacterial cell membrane changes were observed by an image captured using scanning electron microscopy. The results showed that the methanol extract of clove leaf had inhibitory activity on Streptococcus mutans growth, with inhibitory zones of ±32 mm and the minimum inhibitory concentration (MIC) of 20% extract. It was suspected that the mechanism of inhibitory action is by making pores in the bacterial cell membrane. The results also showed that the clove leaves contain bioactive compounds of 3-allyl-6-methoxyphenol-eugenol, caryophyllene, 1,4,7, -cycloundecatriene, 1,5,9,9-tetramethyl, phenol, 2 -methoxy-4- (2-propenyl), and eugenol acetate which can be candidates for producing active compounds to overcome dental caries
AKTIVITAS ANTIBAKTERI EKSTRAK METANOL BUNGA CENGKEH (Syzygium aromaticum) TERHADAP BAKTERI Streptococcus mutans
Full text linkKaries gigi merupakan masalah utama yang paling banyak dijumpai di rongga mulut. Penyakit ini dapat menyerang seluruh lapisan masyarakat dari berbagai kelompok usia dan ekonomi. Salah satu sebab terjadinya karies gigi adanya interaksi dengan mikroorganisme Streptococcus mutans. Tujuan penelitian ini adalah untuk mengetahui aktivitas antibakteri senyawa kimia ekstrak bunga cengkeh (Syzygium aromaticum) terhadap bakteri S. mutans. Metode Penelitian yang digunakan adalah metode true experimental dengan posttest only with control group design. Sampel yang digunakan adalah bunga cengkeh. Ekstraksi dilakukan dengan metode maserasi menggunakan pelarut metanol dan selanjutnya dilakukan vacum evaporator diperoleh bobot ekstrak sebanyak 33,1%. Hasil identifikasi senyawa kimia secara kualitatif ekstrak bunga cengkeh mengandung senyawa alkaloid, flavonoid, terpenoid, dan fenolik. Aktivitas antibakteri dilakukan dengan metode difusi agar dengan mengukur zona bening yang terbentuk. Hasil uji konsentrasi hambat minimum (KHM) diperoleh konsentrasi 25% memiliki aktivitas antibakteri yang baik. Selanjutnya pengujian aktivitas antibakteri dengan melihat zona diameter hambat, diperoleh sebesar 37 mm, dan amfisilin sebesar 28 mm. Ekstrak bunga cengkeh memiliki aktivitas antibakteri yang lebih baik dibandingkan dengan ampisilin
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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