Judul: Korelasi Kadar Seskuiterpena dengan Mutu Gaharu Standar Nasional Indonesia
Abstrak: Sesquiterpene content of agarwoods (Aquilaria malaccensis) of 3 different commercial grades, namely kemedangan, super tanggung A and, super A, representing low to high grades, has been identified. However, parameters designated in Indonesia National Standard (SNI) are merely qualitative, based on some physical properties of this commodity. The purpose of this study was to obtain quantitative chemical parameters in order to complement the existing parameters of SNI. In the identification step, agarwood samples were extracted using 2 different solvents, i.e. ethyl acetate and acetone. Gas chromatography-mass spectrophotometer analyses indicated that sesquiterpenes were present in all agarwood grades. Resin contents in acetone extract for kemedangan, super tanggung A, and super A were 8.5%, 13.3%, and 19.9%, respectively. Sesquiterpene content of acetone extract for kemedangan, super tanggung A, and super A were 6.1%, 7.1%, and 11.9%, respectively, and for ethyl acetate extract were 5.4%, 9.6%, and 13.4%. Resin and sesquiterpene content in acetone extracts consistently increased corresponding to the quality of commercial gaharu. A marker compound obtained in all the quality of agarwoods and agarwood extract was aromadendrene. Aromadendrene content in acetone extract from the lowest to the highest grades of commercial agarwoods were 1.2%, 1.6%, and 2.2%, respectively.
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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: A Continuous Vaccination Strategy in the SVIR Epidemic Model
Abstrak: Vaccination is conducted to minimize the spread of a disease. The vaccination is usually done several times within a fixed time interval. In the SVIR model, it is assumed that individuals do not get immediate immunity following a vaccination program. So according to process of vaccination on SVIR model, there are two strategies, i.e. the continuous vaccination strategy (CVS) and the pulse vaccination strategy (PVS). In this study, only the CVS strategy in epidemic model SVIR is considered. Results of the study indicate that dynamics of the CVS system depends on the basic reproductive number. If the basic reproductive number is less than one, then the disease-free fixed point is asymptotically stable. It means that the disease will eventually disappear from the population. Conversely, if the basic reproductive number is greater than one, then the endemic fixed point is asymptotically stable, which means that the disease will remain exist in the population. Simulation result shows that the vaccination would minimize the spread of disease by reducing the basic reproductive number. If the time for the vaccinated recipients to obtain the immunity, as well as a possibility of vaccinated recipients to be infected are neglected, then the disease will be eradicated. This condition is called an over-evaluating effect of vaccination.
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