Judul: Efektivitas Antimikroba Ekstrak Daun Sembung Rambat (Mikania micrantha H.B.K.) terhadap Bakteri Gram Positif yang Resisten Penisilin
Abstrak: The used of antibiotic which is uncontroled has lead to the emergence of resistant bacteria, such as penicillin-resistant bacteria. Therefore, many research in finding new antimicrobial drugs are barely needed to be conducted. One of the potential herbs is Mikania micrantha known as sembung rambat in Indonesia, an invasive alien species. The aim of this research was to showed effectivity of crude ethanolic extract of Mikania micrantha leaveas in inhibiting the growth of penicillin G resistent positive Gram bacteria. The crude ethanolic extract of Mikania micrantha leaves was tested penicillin G-resistant positive-Gram bacteria. The method used for in vitro effectivity test in this research was well diffusion agar method in various concentrations. The results obtained that crude ethanolic extract of Mikania micrantha leaveas showed effectivity in inhibiting the growth of penicillin G resistent positive Gram bacteria and the effective concentration is 80% (g / ml).
Keyword: penicillin-resistant bacteria, Bogor Agricultural University (IPB), Mikania micrantha, Antimicrobial

Judul: Skrining Efektivitas Ekstrak dan Fraksi Daun Sembung Rambat (Mikania micrantha H.B.K.) terhadap Bakteri dan Dermatofita
Abstrak: The aim of this research was to compare the effectivity of crude ethanolic extract of sembung rambat (Mikania micrantha H.B.K.) leaves and its fractions (n-hexan, chloroform, ethyl acetate, and aquades fraction) against positive-Gram bacteria, negative-Gram bacteria, and dermatophytes. The fractionation method used in this research was liquid-liquid fractionation and the method used for in vitro effectivity test was agar well diffusion method. The result turned that chloroform fraction of sembung rambat leaves showed the best growth inhibitory activity against positive-Gram and most of negative-Gram bacteria compared with crude ethanolic extract and the other fractions, with inhibitory zone: 18.67 + 1.15 mm (S. aureus), 22.33 + 1.53 mm (S. epidermidis), 20.67 + 0.58 mm (B. cereus), 22 + 1 mm (Bacillus sp.), 16.67 + 0.58 mm (E. coli), 15 mm (S. enteridis), and 9.67 + 2.52 mm (P. multocida). The best inhibitory zone against Microsporum canis (21.67 + 1.15 mm) and Microsporum gypseum (23.33 + 0.58 mm) were showed by chloroform fraction; while the best growth inhibitory activity for Tricophyton mentagrophytes (11.67 + 2.08 mm) was showed by ethyl acetate fraction.
Keyword: Mikania micrantha H.B.K., dermatophyte, Antimicrobial, bacteria, Bogor Agricultural University (IPB)

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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