Judul: Gambaran histologis sel spermatogenik pada tikus setelah pemberian ekstrak pegagan (Centella asiatica)
Abstrak: Pegagan (Centella asiatica) is a medicinal plant that is widely used as a brain tonic but not yet known its effects on the male reproductive organs. The purpose of this study was to determine the histological appereance of spermatogenesis stages that found in testes and density of spermatozoa in the epididymis after giving a pegagan extract. This study using 16 rats that were divide into 4 treatment groups. Each treatment is given pegagan extract in different dose (0 mg/kg body weight (bw) as a control, 100 mg/kg bw, 300 mg/kg bw, and 600 mg/kg bw) orally for 8 weeks. The results showed that each pegagan extract treatment generally decreased spermatogenic cell number and density of spermatozoa in the epididymis. The percentage number of spermatogenic cells reduction in parallel to the increasing level of extract doses. The number of spermatogenic cells and density of spermatozoa in the epididymis can be reduced by giving of pegagan extract.
Keyword: Centella asiatica, histological, pegagan, spermatogenesis

Judul: IPB (Bogor Agricultural University)
Abstrak: The Indonesia population growth rate during the past 10 years tend to decrease and nearly reach the ideal rate of one percent of growth per year. This success was supported by family planning program and campaign of using contraception. Unfortunately, almost all contraceptive tools and methods affect women. Various effort needs to be done by promoting men contraception, in order to increase participatory rate of men. Medicinal plants have been used as alternative medicine with an asumption that it perform less side effects, beside other consideration such as easy to find and cheaper than the chemical and commercial medicines. One of the medicinal plants that have been used widely in the community is pegagan (Centella asiatica) that used to treat injuries and improve cognitive function. Pegagan has been reported to have an antifertility properties in male rats. However, the scientific reports on the use of this plant on reproduction purposes are still limited. So that, the purpose of this study is to determine the antifertility effect of pegagan extract and reversibility of reproductive capability in male rats. In the first stage, this experiment was done experimentally with a completely randomized design, consisting of 16 combinations of four treatment doses (0, 50, 150 and 450 mg/BW) and four duration of administration (28, 35, 42 and 49 days). Parameters measured were population of spermatogenic cells, sperm quality and testosterone levels. Results of the experiment showed that the population of late spermatids, sperm concentration, sperm motility and testosterone levels decreased following the treatment, although they were still in a normal range. Results of the experiment also indicated that pegagan extract did not affect the population of spermatogonia, primary spermatocytes and sperm abnormality. It also showed that pegagan still be able to maintain testosterone levels within the normal range. Based on these results, it can be concluded that the dose of 450 mg/kg BW caused the lowest level of late spermatids and sperm concentration if compared to the other paramaters. Twenty eight days administration of pegagan appears to be most efficient duration of administration than any longer time. Results of the experiment also indicated that treatment doses of 450 mg/kg BW and duration of 28 days is still able to maintain testosterone levels in the normal range. Decrease of testosterone levels is associated with inhibition of late stages of spermatogenesis. Based on these results, follow up experiment was carried out to explore the antifertility effects of pegagan and its reversibility. The study was conducted with a complete randomized design, with 8 treatment of combination of dose-duration (450 mg/kg BW-21 day, 600 mg/kg BW-21 day, 450 mg/kg BW-28 days, and 600 mg/kg BW-28 days) and the cessation length of pegagan (1 day and 12 days). Several parameters consisting of the degree of spermatogenesis and sperm quality of male rats were determined. Results of the experiment showed that the degree of spermatogenesis and sperm quality decreased after administration of pegagan. The decrease of spermatogenesis may be due to apoptosis process. The results also showed that 12 days cessation length of pegagan cause the increase of developmental stage, quality
Keyword: antifertility, reproductive function, pegagan, rat

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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