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: Eksplorasi dan identifikasi senyawa anti jamur dari beberapa jenis kayu tropis
Abstrak: Widely used wood preservation is made from synthetic chemistry, where the raw material is non-renewable and environmental unfriendly. One solution is to look for alternative preservations using certain extractive substances from a durable tropical wood as a wood preservative. The main objectives of this study were to determine the potential extractive substances in woods of kupa (Syzygium polycephalum (Mig)), pelawan (Tristaniopsis whiteana (Griff)), palepek baringin (Shorea laevis Ridl), and mahalilis (Palaquium sp.), to evaluate the use of extractive substances as anti-fungal wood decay Schizophyllum commune Fries and Pleurotus ostreatus, and to identify the structure of anti-fungal compound. The maceration extraction method used methanol solvent, and multilevel fractionation used n-hexane, chloroform, ethyl acetate and butanol solvents. The extracts, subsequently, were carried out fungus S. commune and P. ostreatus the tests, and CCB preservative was used as negative control. The result showed that the highest extractive content was in S. laevis, followed by Palaquium sp., T. whiteana and S. polycephalum. Moreover, the results of column chromatography showed that ethyl acetate fraction of S. polycephalum was obtained 8 (G.1-G.8) compounds, the fraction of chloroform of T. whiteana was obtained 8 (PL.1-PL.8) compounds, the fraction of butanol of S. laevis was obtained 16 (PB.1-PB.16) compounds and the fractions of chloroform of Palaquium sp. was obtained 5 (M.1-M.5). Based on the maceration extract, fractionation and column chromatography, all the wood types were capable of inhibiting the growth of the fungus S. commune and P. ostreatus. Structure identifications with LC-MS, 1H and 13C NMR anti-fungal compound for G.2, Pl.3, PB.1.1, and M.2 were 3-O-glucosyl-3’,4’,5-trihydroxyflavonol, Heptanoic acid, 2,3-dihydroxyoctadecanoic acid and 2,3-dihydroxypropylpentadecanoate, respectively .
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Judul: Pengaruh vaksinasi terhadap dinamika populasi pada model SIR (Susceptible-Infected-Recovered)
Abstrak: SIR model can be used to model the spread of diseases in a closed population based on certain assumptions. In this research, the SIR model is formulated by including the factor of vaccination. As the result, the model has been shown to have two equilibrium points, i.e. disease free and endemic equilibrium. A simulation study is carried out to illustrate the model. The results show that some equilibrium points are asymptotically stable. Moreover, a minimum level of vaccination has been defined. For the vaccination level less than the minimum level, increase in the vaccination level results in decrease of the proportion of infected individuals in the corresponding equilibrium point. On the other hand, for the vaccination level greater than the minimum level, increase in the vaccination level results in decrease the proportion of susceptible individuals in the corresponding equilibrium point. Furthermore, when vaccination level is greater than the minimum level, it is found that the time needed for the disease to extinct is shorter.
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