Judul: Pengaruh Lempuyang Gajah (Zingeber zerumbat L.) dan Fraksi Ekstraknya terhadap Kadar Kolestelor, Trigliserida dan Glukosa Darah dan Hati Tikus Sprague Dawley
Abstrak: Lempuyang gajah (Zingiber zerumbet L.) adalah salah satu dari tumbuhan obat tradisional yang sering digunakan sebagai obat luar maupun dalam, disamping sebagai makanan lalapan dan bumbu masakan. Komponen kimia utama yang dikandungnya antara lain minyak atsiri yang terdiri dari senyawa zerumbon, a-pinen, a-kariofilen, kamfer dan sineol. Penelitian ini bertujuan untuk mempelajari pengaruh aktifitas lempuyang gajah dalam bentuk tepung, ekstrak steam distillation, ekstrak etanol 95% dan jamu terhadap kadar kolesterol, trigliserida dan glukosa darah dan hati tikus. Selain itu juga dipelajari sifat fisiko kimia ekstrak lempuyang gajah yang diperoleh dari teknik steam distillation dan ekstraksi dengan pelarut etanol 95%.
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Judul: Potensi Teh Herbal Lempuyang Gajah (Zingiber zerumbet L.) sebagai Antioksidan pada Tikus Sprague-Dawley Hiperkolesterolemia
Abstrak: Hypercholesterolemic conditions can increase lipid peroxidation and as an indicator of the presence of free radicals in the body. This research aimed to determine the efficacy of lempuyang gajah (Zingiber zerumbet L.) herbal tea as an antioxidant to prevent lipid peroxidation in hypercholesterolemic rats. Twenty six rats were divided into 4 following groups: normal, hypercholesterolemia, extract 1 (low dose), and extract 2 (high dose) groups. Hypercholesterolemia were induced in rats by high cholesterol diet (1.5% cholesterol) and oral administration of propil tiourasil (PTU) 0.5 mg/kg bw in six weeks. Before necropsied, rats were given standard diet for the last four weeks. Lipid peroxide concentrations in the liver were analyzed using thiobarbituric acid (TBA) assay with spectrofotometer UVVis at 532 nm. Results showed that feeding cholesterol free diet in the last four weeks normalized liver lipid peroxide concentration in the three treatment groups. The average of all groups were 40.88±13 nmol/g (p=0.317). Addition of extract reduced correlation between liver lipid peroxide concentration and blood cholesterol concentration on the extract groups (1 and 2). This observation suggest that components of lempuyang gajah herbal tea can prevent lipid peroxidation in liver.
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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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