Judul: Pengaruh Media Pertumbuhan terhadap Potensi Antibakteri dan Antihiperglikemik Kapang Endofit Tumbuhan Pesisir Sarang Semut Hydnophytum formicarum
Abstrak: Sarang semut plant is traditionally used for medical purposes. The aim of this research was to observe the antibacterial and α-glucosidase enzyme inhibitor activities of the fungal extracts isolated from sarang semut plant which was cultivated in different culture media. The fungus cultivated using PDB medium grew faster in comparison with one in Hagem medium. During 21 days of cultivation, pH value was 4-5. The best results of antibacterial activity against Escherichia coli and Staphylococcus aureus were extract of culture medium with PDB treatment in 18 days cultivation, with inhibitor zone was 17.6 mm and 16.5 mm, respectively. IC50 value for α-glucosidase inhibitor was 9345.777 ppm showed by extract of culture in Hagem medium.
Keyword: Bogor Agricultural University (IPB), Hydnophytum formicarum., endophytic fungi, biomass, antihyperglycemic, antibacterial

Judul: Kapang Endofit dari Tumbuhan Pesisir Sarang Semut (Hydnophytum formicarum) dan Potensinya sebagai Antihiperglikemik
Abstrak: Epiphytic plant sarang semut Hydnophytum formicarum is one of the coastal plants that used as traditional medicine. Microbial endophytic can produce secondary metabolite compounds similar to compounds produced by plants of its host. The purpose of this research was to determine the activity of the endophytic fungi extracts to inhibit α-glucosidase. This research included isolation, cultivation, extraction, characterization, and assay the antihyperglycemic activity. The results showed 7 types of endophytic isolates included 1A, 1B, 2A, 2B, 3, 6A and 6B with a different characterization. Endophytic fungus 3 and 6B were the selected isolate based on antagonism test. A fungal growth patterns showed that the stationary phase of the fungus was on the 21th day until 24th day. Phytochemical test on extracts of mycelium and culture media showed that the extracts containing flavonoids and phenols hydroquinone. The screening results showed that the fungal broth extract with concentration of 20000 ppm had α-glucosidase inhibitor activity 72.63%.
Keyword: α-glucosidase enzyme activity, sarang semut, endophytic fungi, antihyperglycemic

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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