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: Aktivitas Antibakteri dan Antihiperglikemik Kapang Endofit RS-6B dari Sarang Semut pada Perlakuan Media Berbeda
Abstrak: Sarang semut Hydophytum formicarum merupakan salah satu tumbuhan epifit pada pohon bakau yang digunakan sebagai obat tradisional oleh masyarakat pedalaman. Tujuan penelitian ini adalah menentukan pengaruh media yang berbeda terhadap pertumbuhan kapang dan aktivitas antibakteri dan antihiperglikemik ekstrak kapang. Komponen bioaktif terbanyak dihasilkan pada hari ke-21 fermentasi. Kapang mencapai fase pertumbuhan stasioner pada hari ke-9 sampai hari ke-21 pada media kultur PDB dan Hagem. Nilai pH kedua media berada pada rentang 4-5. Aktivitas antibakteri terbaik diperoleh pada hari ke-12 untuk media PDB dan hari ke-9 untuk media Hagem yang aktif terhadap bakteri Escherichia coli dengan diameter 16,4 mm dan 13,9 mm dan Staphylococcus aureus dengan diameter 14,5 mm dan 14,4 mm. Ekstrak terbaik dari aktivitas antibakteri selanjutnya ditunjukkan dengan aktivitas enzim α-glukosidase dengan nilai IC50 sebesar 8002,3 ppm.
Keyword: aktivitas antibakteri, aktivitas enzim α-glukosidase, antihiperglikemik, kapang endofit, tumbuhan sarang semut

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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