Judul: Potensi ekstrak daun jambu biji merah (psidium guajava) dan daun sirsak (annona muricata) untuk menghambat proliferasi sel kanker raji
Abstrak: Daun jambu biji merah (Psidium guajava) mengandung senyawa kuersetin dan daun sirsak (Annona muricata) mengandung kaempferol. Kedua senyawa flavonoid tersebut memiliki potensi menghambat proliferasi sel kanker. Tujuan penelitian ini adalah mengevaluasi potensi fraksi ekstrak daun jambu biji merah (fraksi kaya-kuersetin) dan fraksi ekstrak daun sirsak (fraksi kaya-kaempferol) dalam menghambat proliferasi sel kanker Raji dengan metode ekstraksi maserasi. Ekstrak metanol didapatkan dengan memaserasi serbuk sampel setelah sampel dibebaskan dari senyawa nonpolar menggunakan n-heksana. Ekstrak dari setiap sampel dimurnikan menggunakan kromatografi cair vakum dan didapatkan 0.28% fraksi kaya-kuersetin, dan 2.00% fraksi kaya-kaempferol. Kadar aglikon kuersetin dan kaempferol berdasarkan kromatografi cair kinerja tinggi berturut-turut 1.27 dan 0.67 ppm. Kedua fraksi diuji efek penghambatannya terhadap sel Vero (sel normal) dan sel Raji (se kanker darah). Persen penghambatan kedua fraksi terhadap sel Vero sebesar 200 ppm. Hasil pada sel Raji menunjukkan rendahnya persen penghambtan kedua ekstrak, terutama fraksi kaya-kuersetin tidak menunjukkan penghambatan sel. Berdasarkan hasil tersebut disimpulkan bahwa fraksi kaya-kuersetin dan kaempferol tidak berpotensi dalam menghambat proliferasi sel kanker Raji. Kata kunci: antikanker, jambu biji merah, kaempferol, kuersetin, sirsak
Keyword: nticancer, guava, kaempferol, quercetin, soursop

Judul: Kuersetin dari Ekstrak Daun Jambu Biji Merah (Psidium guajava) dan Kinerjanya sebagai Penghambat Proliferasi Sel Kanker
Abstrak: Red guava leaf (Psidium guajava) extract has been known to inhibit cancer cell proliferation. However, further studies on the activity of flavonoids in red guava leaves as an anticancer agent has not been done. This study aims to test the inhibitory activity on Raji cells (ATCC CCL-86) by quercetin in guava leaves. Methanol crude extract was fractionated using vacuum liquid chromatography and column chromatography techniques to obtain fraction rich of quercetin. Fractionation of the crude methanol extract gave a fraction which shows a spot at Rf 0.675, which is similar to that of standard quercetin. Identification of quercetin fraction with liquid chromatography-mass spectrometry showed the fragment ion spectra of the quercetin (m/z 150, 151, 152). The quercetin fraction has been tested for its activity toward Raji cells and Vero cells. The quercetin fraction inhibited proliferation of Raji cells by 60%, at a concentration of 100 mg mL-1, but only inhibits the proliferation of Vero cells by 10%. This result indicates the quercetin fraction of guava leaf is able to inhibit the proliferation of Raji cells, but not toward Vero cells.
Keyword: quercetin, Psidium guajava, flavonoids, cancer cells proliferation

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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