Judul: Ciri kimiawi asam resin kopal  Agathis loranthifolia
Abstrak: Copal is originated from exudate of Agathis loranthifolia trees, which flows out from the tapping. Indonesian copal includes manila copal, is divided into four groups among others: bua, loba, melengket and Pontianak copal. Research of resin acid from copal has not been widely studied. Therefore, purpose of this study is to identify resin acids of copal from Sukabumi and Ternate area. Extraction was done using acetone:MeOH (9:1) solvent, followed by fractionation using some solvents, i.e. n-hexane, ethylacetate, H2 O, and acetone:MeOH (9:1). Identification was done using gas chromatography-mass spectrometer (GCMS). The quality of copal was evaluated based on SNI 7634-2011. Resin acids copal from Sukabumi identified by GCMS are 44% limonene, ethylene oxide hexamer, cis-limonene oxide, toluene, trans-carveol, 2-siclohexane-1-one, trans-limonene oxide, and alpha pinene. Copal from Ternate are 37% limonene, ethylene oxide hexamer, preludin, toluene, carveol 1, 2-siclohexane-1-one, acetat acid, hexaethylen glycol, champhen, and trans-limonene oxide. However, fractionation of the copal converted resin acids to 100% carvone. These results suggest that limonene are easily oxidized to carvone. Properties of manila copal from Sukabumi and Ternate fall to the first class, and are possible to be improved to the premium class by removing some dirt compount.
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Judul: Identifikasi komponen kimia empat tingkat mutu gaharu
Abstrak: Agarwoods (Aquilaria malaccensis) with 4 different commercial grades has been identified, namely kacangan B, teri B, medang A, and medang B, from the highest to the lowest grade. In this work, resin content tends to increase as the grade increases. However, the resin content does not have correlation with the content of sesquiterpene and chromone which determine the grade of agarwoods. In isolation step, the agarwood samples were fractionated using gradient column chromatography method with hexaneethyl acetate as eluent and were grouped according to its Rf point. Identification of samples using gas chromatography-mass spectrophotometer showed the presence of 10 sesquiterpenes and 3 chromones in various levels.
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Judul: Dynamical System of Hepatitis B in Three Groups with Vaccination
Abstrak: The aim of this study is to modify the hepatitis B transmission model in three age groups involving vaccination from the model conducted by Zhoe and Zhang.The method used is to analyze the stability of the fixed point and its basic reproduction number (R_0). Performed stability analysis and numerical simulation to see population dynamics. Next, a sensitivity analysis of the parameters was carried out to see its effect on R_0. From the analysis obtained two fixed points, namely non-endemic and endemic fixed points. Non-endemic fixed points are locally asymptotically stable if R_0 <1 Meanwhile, the endemic fixed point is locally asymptotically stable if R_0 > 1. Hepatitis vaccination affects the number of susceptible population, because the more successful the vaccination, the smaller the number of susceptible populations so that the smaller the population will be infected.
Keyword: Dynamic, Hepatitis B, Vaccine, Mathematical model