Judul: Isolasi dan Elusidasi Struktur Senyawa Aktif dari Daun Ficus deltoidea Jack. Dibimbing
Abstrak: Tabat barito (Ficus deltoidea Jack) adalah salah satu tumbuhan hutan yang memiliki metabolit sekunder unik dan beragam bioaktivitas. Partisi ekstrak EtOH daun tabat barito (9.17 g) dengan heksana, CH2Cl2, dan n-BuOH menunjukkan lapisan CH2Cl2 (1.51 g) adalah lapisan yang memiliki toksisitas paling ampuh (LC50 13.31 μg/mL) terhadap embrio ikan zebra (Danio rerio). Fraksionasi lapisan CH2Cl2 menghasilkan 6 fraksi A–F. Fraksi teraktif F (393.2 mg, LC50 33.34 μg/mL) menyebabkan malformasi mayor (63%) pada sumbu tubuh embrio ikan zebra. Pemurnian lebih lanjut fraksi F dengan MPLC dan kromatografi kolom menghasilkan senyawa 2 (3.9 mg) polar (larut dalam CD3OD). Senyawa 2 mengandung m/z 519.2236 berdasarkan data HRESIMS. Elusidasi spektrum NMR 1H dan DQF-COSY pada senyawa 2 menunjukkan sedikitnya terdapat 2 substruktur (I-II), yaitu suatu disubtitusi alkena I dan II serta tidak memiliki gugus aromatik dan memiliki ikatan C-O atau C-N.
Keyword: elusidasi struktur, embrio ikan zebra, Ficus deltoidea, HRESIMS, NMR

Judul: Optimalisasi ekstraksi komponen bioaktif daun tabat barito (Ficus deltoidea)
Abstrak: The plants may contain the important compound useful for human. Tabat barito (Ficus deltoidea) has been used as a traditional medicine. Previous study observed that the plant contains several active subtances like alkaloid and flavonoid subtances. This study was examined various extraction's conditions such as choice of solvent, ratio of solvent, extraction time and the division of solvent and time of extraction in order to produce an optimal yield of bioactive compound mixture. Extraction technique used in this research was a modification of Harhorne's method. There were three solvent used. Among them, methanol gave a higher yield (3.86 %) compared to ethyl acetate (2.26 %) and hexane (1.60 %). The ratio of solvent used were 1 :5, 1:7 and 1:9 and kept for 24, 48 and 72 hours. The higher solvent ratio and extraction time, the higher yield of extracts produced. However, the yield obtained from extraction using ratio 1:7 in 48 hours and 72 hours was slightly differed. Therefore, considering the cost of energy and time required for the process, the extraction time of 48 hours and solvent ratio 1:7 produces an optimum yield.
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Judul: Query Expansion based on Bilingual Dictionary Using Conditional Probability
Abstrak: Query expansion is a technique that can be used to bridge vocabulary gaps between queries and documents in the collection. With query expansion, user will be helped to formulate queries well so that user will optimize the search result. In this study, the expansion term was resulted from the translation of bilingual dictionary. Subsequently, several terms of expansion were elected based on the closeness of its relationship with the original query. This research showed that conditional probability can be used to select expansion term in bilingual translation method query expansion. The result of 1000 documents was more than 97% relevan document can be retrieved by this system. The more expansion term used, the larger number relevan document was retrieved.
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