Judul: Effect of cajuputs candy formulas on competitive capacity of streptococcus sanguinis upon streptococcus mutans in multispecies biofilm.
Abstrak: Cajuputs candy development as a functional food has been shifted to maintain the oral health. Cajuputs candy is classified as hard candy which utilized cajuput and peppermint oil as its flavor components. Streptococcus sanguinis is a health-associated species which can control the growth of cariogenic species, S. mutans. These two oral Streptococci have antagonistic interaction which plays a role in preventing dental caries formation. The aim of this research is to determine the effects of two type of cajuputs candy, i.e. Sucrose Cajuputs Candy (SCC) and Non-Sucrose Cajuputs Candy (NSCC), on competitive capacity of S. sanguinis upon S. mutans in multispecies (S. sanguinis+S. mutans) biofilm, which is indicated by its ability to form biofilm, control the growth of S. mutans, and expressed spxB mRNA. The spxB mRNA expression reflected hydrogen peroxide (H2O2) production by S. sanguinis. Volatile constituents of cajuputs candy’s flavors were analyzed using Gas Chromatography-Mass Spectrometry (GC-MS). In vitro biofilm assay with optical density (OD) measurement was used to examine the potency of cajuputs candy in inhibiting the formation of multispecies biofilm. Quantitative real-time polymerase chain reaction (real-time PCR) techniques were applied for quantification of spxB mRNA and relative amount of total DNA bacterium in the biofilms. Several reported antimicrobial components, i.e. 1,8-cineole (23,67%), α-terpineol (9,17%), menthol (7,29%), β-caryophyllene (6,78%), menthone (3,30%), and terpinen-4-ol (1,86%) were detected in SCC. Meanwhile, the reported antimicrobial components, i.e. menthol (13,32%), α-terpineol (9,97%), 1,8-cineole (8,48%), β-caryophyllene (7,64%), menthone (4,43%) and terpinen-4-ol (1,28%) were also detected in NSCC. The biofilm assay showed that the exposures of SSC and NSCC were effective in inhibiting multispecies biofilm. Biofilm inhibition caused by SCC was 59,2% and NSCC was 68,2%. Moreover, SCC and NSCC exposures also decreased the relative amount of total DNA in multispecies biofilm to be 1,20% and 1,04% compared to the control (100%), respectively. These reductions were indicating that SCC and NSCC could inhibit biofilm formation of S. sanguinis and S. mutans, in vitro. Exposures of candy formula without flavor, i.e sucrose candy without flavor and non-sucrose candy without flavor, also affected biofilm formation. The ability to form biofilm affected by sucrose candy and non-sucrose candy without flavor exposures were decreased 36,9% and 47,1% compared with the control, respectively. However, sucrose candy and non-sucrose candy without flavor exposures were induced bacterial growth with percentage of total DNA in the biofilm were 184,77% and 221,29% increase compared with the control, respectively. It seems that utilization of sucrose without addition of antibacterial component, e.g. essential oil as flavoring agent, could induce bacterial growth. Even a non-sucrose utilization, in this study is isomalt - a non-cariogenic polyol-, with a long exposure time (approx. 20 hours) in this research could be fermented by these Streptococci and can be used for their growth. This indicated that cajuput and peppermint oil in SCC and NSCC showed antibacterial activity. The proportion of S. sanguinis DNA in multispecies biofilms was lower than S. mutans DNA in all samples, which ranged from 35 to 42% for S. sanguinis and 58 to 65% for S. mutans. This bacterial DNA proportion was not statistically significant compared with
Keyword: cajuputs candy, biofilm inhibition, Streptococcus sanguinis, Streptococcus mutans, spxB mRNA

Judul: Perubahan Proporsi Jumlah Streptococcus mutans terhadap Total Bakteri Mahasiswa setelah Mengkonsumsi Cajuputs Candy
Abstrak: The formation of plaque which causes caries process is substantialy influenced by the presence of Streptococcus mutans (S. mutans) and its proportion to the total amount of bacteria in dental plaque. One of methods for caries preventing is by controlling the potential of these bacteria to form colonies and grow as part of the mass of biofilm on the surface of the tooth (dental plaque). This effort can be done by consuming Cajuputs Candy, a functional food in the form of candy which has antibacterial bioactive compounds. This reserch was aimed to analayze the potential of two type of Cajuputs Candy ,i.e. Cajuputs Candy Sucrose (CCS) and Cajuputs Candy Non Sucrose (CCNS) in decreasing the amount of S. mutans and its proportion upon the total amount of bacteria in dental plaque by Quantitative Real Time Polymerase Chain Reaction (qPCR) technique. The treatments studied were one grain of CCS and CCNS consumption respectively once and twice a day. The results showed that both CCS and CCNS potentially reduced the quantity of S. mutans, its proportion to the total amount of bacteria, and the number of non- cariogenic bacteria in dental plaque. Non sucrose ingredient usage in Cajuputs Candy could increase the effectiveness in reducing the quantity of S. mutans in dental plaque. Consuming a CCNS twice per day has the optimum effect in reducing the quantity of S. mutans and its proportion to the total amount bacteria.
Keyword: Bogor Agricultural University (IPB), qPCR, CCNS, CCS, dental plaque, total bacteria, S. mutans

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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