Judul: Potensi antioksidasi bebrapa ekstrak senyawa bahan alam yang berkhasiat sebagai antikanker
Abstrak: This research was conducted to compare antioxidation potency of some extracts from natural materials compound ivhich have anticankr poiency. The natural compounds tested were ex&& of mohkota dewa, d m d k a , sahbung nyawa, temuputih, and tofu whey. Analysis have been done using 200 ppm total an centration for each extract tested. Natural antioxidant vitamin E (a-tocopherol 0 ppm) is used for comparison. The degree of oxidation was measured by $Ilobarbituric acid (TBA) method in vitro.
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Judul: Analisis aktivitas antioksidan alami dari delapan jenis biji buah-buahan
Abstrak: Penelitian karena adanya tentang antioksidan alami banyak dilakukan kekhawatiran di sebagian kalangan peneliti mengenai penggunaan antioksidan sintetik seperti halnya BHA, BHT dan sebagainya terhadap akibat yang ditimbulkannya. Penelitian yang dilakukan terhadap ekstrak kasar antioksidan alami dari delapan jenis biji buah-buahan (alpukat, sawo, sirsak, nangka, durian, rambutan, kufa dan mede) ternyata menunjukkan hasil adanya aktivitas antioksidan dalam masing-masing ekstrak tersebut. Dari hasil analisis aktivitas antioksidan dengan menggunakan metoda absorbsi oksigen yaitu dengan menggunakan alat oksigenmeter, ekstrak kufa menunjukkan aktivitas tertinggi (10.3 kali) dibandingkan dengan kontrol (tanpa penambahan antioksidan) sedangkan aktivitas terendah terdapat pada ekstrak alpukat (1.3 kali), sedangkan ekstrak lainnya sirsak (7.3 kali), mede (8.5 kali), rambutan (2.1 kali), durian (2.5 kali), nangka (2.3 kali), sawo (6.1 kali). Analisis asam lemak terhadap minyak yang diperoleh dari masing-masing biji buah-buahan menunjukkan adanya kandungan asam lemak tidak jenuh (Oleat, linoleat dan linolenat) yang cukup tinggi dan ini mendukung dugaan adanya antioksidan dalam ekstrak metanol dari masing-masing biji buah-buahan.
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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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