Judul: Antibacterial Activity of Trigona spp. Bee Propolis From Pandeglang Against Enterobacter sakazakii.
Abstrak: Propolis has many advantages and specific potencies, due to its properties as antibacterial, antivirus, and anticancer. The characteristics and properties of E. sakazakii has been studied well due to its physiological properties and resistances in the environment. The research aim is to determine the propolis potency of Trigona spp as antibacterial agent against E. sakazakii. Propolis was extracted from bee hives of Trigona spp using maceration method with ethanol 70% (propolis extract) yielded 17,76% extract. The antibacterial activity test was performed by a modified agar well diffusion against three isolates of bacteria E. sakazakii IB-19b, IB-29a, and ATCC 35217. Through the initiation test, propolis activity was higher than commercial propolis, and lower than ampicillin. The effectivities of propolis extract to commercial propolis for each isolate IB-19b, IB-29a, and ATCC 35217 were 143,99%, 169,65%, and 155,76% respectively. The effectivities of propolis extract to ampicillin for each isolate IB-19b, IB-29a, and ATCC 35217 were 39,37%, 38,94%, and 47,37% respectively. The minimum inhibition concentration differed for each isolate, the minimum inhibition concentration for IB-19b, IB-29a, and ATCC 35217 were 12,50%, 25,00%, and 50,00% respectively. The propolis activity to each isolate showed the concentration dependent activity, the antibacterial activity decrease as the propolis concentration decrease.
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Judul: Potensi antibakteri propolis lebah Trigona spp asal Bogor
Abstrak: Propolis contains resinous substances collected by honey bees from various plant sources. Analysis of numerous samples from different geographic regions led to the disclosure that the chemical composition of propolis is highly variable depends on the specificity of the local flora at the site of collection and thus on the geographic and climatic characteristics of this site. This fact results in the striking diversity of propolis chemical composition, especially of propolis originating from tropical regions. The ethanol extract of Trigona spp propolis collected in Bogor, Indonesia was prepared an assayed to get information about it’s potential ability as antimicrobial substance. Antimicrobial activity was determined by disk diffusion assay. The result of this study shows that the propolis more effective against Gram positive bacterias, Bacillus subtilis and Staphylococcus aureus than Gram negative, E. coli and Pseudomonas aeruginosa. Minimum inhibitory concentration of extract were up to 1.563% against the Gram positive bacterias, and 3.125% against the Gram negative bacterias.
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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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