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: Pengaruh Paparan Flavor Pada Cajuputs Chewy Candy Non-Sukrosa Terhadap Kuantitas Streptococcus Mutans Secara In-Vivo.
Abstrak: Karies gigi merupakan masalah kesehatan gigi dan mulut yang mayoritas diderita oleh masyarakat Indonesia. Salah satu pangan fungsional yang sudah dikembangkan saat ini untuk pencegahan karies gigi adalah cajuputs candy. Cajuputs candy merupakan jenis permen keras yang dikonsumsi dengan cara dikulam, sehingga diduga memiliki waktu kontak flavor yang terbatas. Untuk mengoptimalkan potensi cajuput candy sebagai produk kesehatan mulut, dilakukan pengembangan produk cajuput candy (permen keras) menjadi cajuputs chewy candy (permen lunak) dan optimasi flavor. Optimasi flavor dilakukan untuk merangsang sekresi aliran saliva yang lebih banyak melalui gerakan mastikasi dan rangsangan flavor. Penelitian ini bertujuan untuk mengevaluasi lama dan intensitas paparan flavor pada cajuputs chewy candy non-sukrosa dalam menekan kuantitas Streptococcus mutans. Konsentrasi cajuputs chewy candy non-sukrosa diperoleh berdasarkan kesukaan konsumen, yaitu konsentrasi cajuputs oil flavor x % (formula 1) dan x+0.36 % (formula 2). Potensi cajuputs chewy candy non-sukrosa diukur secara in-vivo dengan cara menggunakan saliva manusia. Flow rate saliva, pH, dan kuantitas Streptococcus mutans telah dilakukan pengukuran. Pengujian lama dan intensitas paparan flavor dilakukan dengan menggunakan metode time intensity, guna mengetahui komposisi flavor yang memiliki kontribusi paling besar dalam merangsang saliva manusia. Hasil penelitian menunjukkan bahwa lama dan intensitas paparan flavor berpengaruh pada peningkatan flow rate, pH, dan jumlah Streptococcus mutans pada saliva. Stimulasi dengan pengunyahan dan paparan flavor dari cajuputs chewy candy non-sukrosa formula 1 dan formula 2 memberikan peningkatan flow rate saliva yang signifikan (p < 0.05). Flavor yang memiliki lama dan intensitas paparan flavor terbesar adalah flavor peppermint pada formula 2. Paparan flavor yang besar pada formula 2 menghasilkan flow rate saliva yang lebih besar pula dibandingkan formula 1. Meningkatnya flow rate saliva menyebabkan terjadinya peningkatan pH saliva yang signifikan (p < 0.05). Peningkatan nilai pH mendekati pH netral menyebabkan penurunan kuantitas Streptococcus mutans. Pada saliva yang distimulasi dengan permen formula 2 menunjukkan kontribusi yang lebih baik dalam menekan kuantitas Streptococcus mutans hingga tidak berbeda nyata dari sampel saliva yang diambil setelah menyikat gigi (kontrol) (p > 0.05).
Keyword: Cajuputs chewy candy non-sukrosa, flow rate saliva, paparan flavor, pH saliva, Streptococcus 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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