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: Histomorfologi tubulus seminiferus dan kelenjar prostat tikus (Rattus Norvegicus) serta konsentrasi hormon androgen pasca pemberian ekstrak purwoceng (Pimpinella Alpina Molk.)
Abstrak: Indonesia is one of the countries which has many kinds of herbal plants. Pimpinella alpina Molk. well known as purwoceng is one of Indonesian herbal plants which have aphrodisiaca actions may enhance libido in males. Moreover, it has been reported that an increase the levels of LH (lutheinizing hormone) and testosterone in blood serum of male rats given the purwoceng extract. The increase of the LH and testosterone level thought to affect the primary and secondary organs in males and level of androgens hormones (testosterone and dihydrotestosterone or DHT). The objective of these experiment was to determine the spermatogenesis, prostate glands activity and the production of androgen hormone (testosterone and DHT) of rats after given of purwoceng extract and it influence of dose and age. The treatment were given orally for 14 days in three age groups (puberty, adult and old) of male rats by received the dose of 25 mg and 50 mg and 0 mg as control. The results shows an increase of the stage of spermatogenesis in the seminiferous tubules after all age groups received purwoceng extract with 50 mg dose of purwoceng was the best since it had the highest response. In addition, these experiment shows there has been an increase of the percentage of prostate glands activity producing prostate fluid. The animals who received the 50 mg purwoceng extract showed the highest response at any age. The effect of the purwoceng extract on the concentrations of androgens (testosterone and DHT) was higher and lower in some age group, but has not perfomed significant effects (p> 0.05). In conclusion of these experiment shows the stage of spermatogenesis, prostate glands activity and the production of androgen hormones increases at all ages, while at the age of puberty the DHT hormone production decreases after giving purwaceng extract.
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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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