Judul: Peran Propolis Trigona spp. Asal Pandeglang Terhadap Tiga Bakteri Asam Laktat
Abstrak: Propolis is known to have an antimicrobial activity and can prevent various diseases. Propolis consumption is feared to have negative impact on the activity of digestive lactid acid bacteria (LAB). The aim of this research was to examine the effect of propolis on the growth and lactid acid production of three LAB. Propolis concentrations examined were 0% (control), 0,2%, 0,6%, 1% and commercial propolis at 0,4% concentration. The parameters analyzed were the growth of bacteria counted with Total Plate Count (TPC) method and lactid acid production using titrable acidity analysis. Propolis at 0,6% concentration stimulated the growth of Lactobacillus casei subsp. rhamnosus (23,725x108 cell/mL), but inhibitted the average lactid acid production (0,071%) lower than control (0,149%). Propolis did not affected the growth of Streptococcus thermophillus, but propolis at 0,6% concentration stimulated the average lactid acid production (0,182%) higher than control (0,112%). Propolis inhibitted the growth of Lactobacillus delbrueckii subsp. bulgaricus, but at 0,2% concentration, its population was still highest (3,775x108 cell/mL) and the average lactid acid production was stimulated (0,195%) higher than control (0,123%).
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Judul: Pengaruh Propolis Trigona spp Asal Pandeglang Terhadap Beberapa Isolat Bakteri Usus Sapi dan Penelusuran Komponen Aktifnya
Abstrak: Propolis has been shown to have antimicrobial activity.This research dealts with analysis of effect of Trigona spp propolis on some bacterial isolated from cattle intestine and analysis of propolis active components. In the first step, propolis was extracted from bee hives by maceration technique using ethanol 70 percent. In the second step, propolis was subjected to antibacterial activity tests against pathogenic and nonpathogenic bacteria isolated from cattle intestine using agar diffusion method. The third step was phytochemycal analysis to test the presence of terpenoid, alkaloid, and flavonoid using Harborne method. The fourth step was analysis of active compounds of propolis through fractination using the Thin Layer Chromatography (TLC) and column chromatography methods. The fifth step, examination of antibacterial activity from factions to E. coli bacteria. And the last step was determination of active agents from the fraction of propolis which had higher antibacterial activity, by GC-MS technique. The results showed that yield of propolis was 17.23%. Antibacterial activity tests showed that propolis inhibited growth of pathogenic bacteria was 64.102 %, and non pathogen bacteria was 35.89%. The results of phytochemical analysis showed that propolis contained tanin, flavonoid and steroid. Determination of active agents showed the presence of eight fractions. Test on antibacterial activity of fractions to E. coli bacteria, showed that fraction C has the highest antibacterial activity. GC-MS analysis showed that fraction C contained 24 compounds. The biggest compound from fraction C was similar to 9,19-cyclolanost-24-en-3-ol, ( 3.beta). This compound had retention time of 40.25 minute and wide area of 49.91%. This compound can inhibit the growth of bacteria.
Keyword: Trigona spp, Propolis, Cattle intestine bacteria, Antibacterial agent, Active compounds

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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