Judul: Aktivitas Antioksidan Ekstrak Kemedangan Pohon Penghasil Gaharu Hasil Inokulasi Jenis Aquilaria microcarpa dan Gyrinops verstegii
Abstrak: Agarwood is a non-timber forest product commodity which is traded because of its distinctive fragrance. Kemedangan from gaharu was assumed to have secondary metabolites that are potential as antioxidant. This study aimed to investigate the phytochemicals, toxicity and antioxidant activites of kemedangan from Aquilaria microcarpa and Gyrinops verstegii trees with and without inoculation by Fusarium fungi. Phytochemical assay of ethyl acetate and methanol extract revealed the presence of phenolics, flavonoids, triterpenoids, and alkaloids. The toxicity evaluation using brine shrimp lethality test showed that all extracts were potential as bioactive compounds with 50% lethal concentration value ≤1000 ppm. Antioxidant activities which were measured by using 2,2- diphenyl-1-picrylhidrazyl free-radical scavenging method showed that all extracts had antioxidant activities with 50% inhibition concentration value ≤200 ppm except A. microcarpa ethyl acetate extract from inoculated samples with IC50 of 411 ppm.
Keyword: agarwood, antioxidant, Aquilaria, Gyrinops, kemedangan

Judul: Uji Aktivitas Antikanker Ekstrak Kemedangan Pohon Penghasil Gaharu Hasil Inokulasi
Abstrak: The phytochemical contents and anticancer activities of kemedangan from agarwood-producing trees inoculated with fungi have been studied to increase the utility value. The simplicias were macerated in n-hexane to remove triglycerides, and the residues were further macerated in ethyl acetate and methanol, respectively. Phytochemical test on ethyl acetate and methanol extracts showed the same results, but with different quantities. Toxicity test with brine shrimp showed that all samples were potential as active compounds and the lowest 50% lethal concentrations were shown by ethyl acetate extract of uninnoculated Aquilaria microcarpa and methanol extract of inoculated A. microcarpa, 18.77 and 44.01 ppm, respectively. In vitro anticancer test of methanol extract from inoculated A. microcarpa showed 50% inhibition concentration value of 298.53 ppm, much higher than the commercial anticancer drug, doxorubicin. Based on these results, both extracts were not potential as anticancer.
Keyword: agarwood, anticancer, kemedangan, phytochemical, toxicity

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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