Judul: In Vitro Antibacterial Activity of Turmeric  Extract against Klebsiella sp. Origin of Cloaca Broiler Chicken
Abstrak: Klebsiella sp. adalah bakteri patogen penyebab infeksi saluran pernapasan yang dapat membahayakan manusia serta hewan. Kunyit (Curcuma domestica Val.) adalah salah satu tanaman tradisional yang dimanfaatkan untuk mengatasi resistensi bakteri terhadap antibiotik. Penelitian ini bertujuan untuk mengetahui aktivitas antibakteri dari ekstrak kunyit terhadap isolat Klebsiella sp. secara in vitro. Metode penelitian terdiri dari re-identifikasi isolat Klebsiella sp., proses ekstraksi kunyit dengan metode maserasi menggunakan etanol 96%, lalu proses evaporasi, dan uji fitokimia ekstrak kunyit. Pengujian aktivitas antibakteri ekstrak kunyit dilakukan dengan menggunakan metode difusi sumur dengan konsentrasi 100, 80, 60, 40, dan 20%. Analisis data untuk mengetahui efektivitas berbagai konsentrasi ekstrak kunyit terhadap Klebsiella sp. dilakukan dengan program SPSS. Hasil uji aktivitas antibakteri menunjukkan bahwa ekstrak kunyit memiliki kemampuan untuk menghambat pertumbuhan Klebsiella sp. Hal ini terlihat dengan munculnya diameter zona hambat di sekitar sumur pada konsentrasi 100, 80, 60, 40, dan 20% dengan rata-rata diameter zona hambat secara berurutan 12,2 mm, 11,5 mm, 10,7 mm, 10,7 mm, dan 10,2 mm. Hasil uji Kruskal-Wallis menunjukkan bahwa setiap konsentrasi ekstrak kunyit dapat menghambat pertumbuhan Klebsiella sp. Hasil uji Mann-Whitney menunjukkan hasil yang beragam pada setiap konsentrasinya., Klebsiella sp. is pathogenic bacteria that cause respiratory tract infections that can harm humans and animals. Turmeric (Curcuma domestica Val.) is one of the traditional plants used to treat bacterial resistance to antibiotics. This study aims to determine the in vitro antibacterial activity of turmeric extract against Klebsiella sp. isolates. The research method consisted of re-identification of Klebsiella sp. isolates, the extraction process of turmeric made by maceration method with 96% ethanol, then evaporation process, and phytochemical test of turmeric extract. The antibacterial test done by using well diffusion method with concentrations of 100, 80, 60, 40, and 20%. Data analysis to determine the effectiveness of various concentrations of turmeric extract against Klebsiella sp. was carried out using the SPSS program. The results of the antibacterial activity test showed that turmeric extract had the ability to inhibit the growth of Klebsiella sp. This can be seen by the appearance of the diameter of the inhibition zone around the well at concentrations of 100, 80, 60, 40, and 20% with an average inhibition zone diameter of 12,2 mm, 11,5 mm, 10,7 mm. mm, 10,7 mm, and 10,2 mm. The results of the Kruskal-Wallis test showed that any concentration of turmeric extract could inhibit the growth of Klebsiella sp. The results of the Mann-Whitney test showed varying results at each concentration.
Keyword: antibakteri/antibacterial, bakteri Gram negatif/Gram negative bacteria, difusi/diffusion, kunyit/turmeric, Klebsiella sp

Judul: IN VITRO ANTIBACTERIAL ACTIVITY TEST OF  GARLIC EXTRACT (Allium sativum L.) AGAINST Klebsiella sp.
Abstrak: Klebsiella sp. merupakan bakteri infeksius dari famili Enterobacteriaceae yang dapat menginfeksi hewan maupun manusia. Ekstrak bawang putih digunakan sebagai antibakteri alternatif untuk meminimalisir penggunaan antibiotik komersil. Metode penelitian adalah uji re-identifikasi isolat Klebsiella sp. dan ekstraksi simplisia bawang putih. Uji aktivitas antibakteri dilakukan secara in vitro terhadap bakteri Klebsiella sp. menggunakan ekstrak bawang putih dengan konsentrasi 20%, 40%, 60%, 80%, dan 100%. Analisis data penelitian dilakukan dengan uji Shapiro-Wilk (normalitas) menunjukkan data berdistribusi tidak normal. Uji dilanjut dengan Kruskal-Wallis untuk menjelaskan adanya perbedaan yang signifikan (P < 0,05), hasil uji Kruskal-Wallis menghasilkan data diameter zona hambat Klebsiella sp. memiliki p = 0,003 sehingga p < 0,05 yang berarti ekstrak bawang putih mampu bekerja sebagai antibakteri terhadap Klebsiella sp. Kemudian dilanjut uji Mann-Whitney untuk mengetahui besar perbedaan aktivitas antibakteri dari setiap kelompok uji. Ekstrak bawang putih konsentrasi 20% dan 40% memiliki daya hambat sedang, sedangkan ekstrak bawang putih konsentrasi 40%, 60%, dan 100% memiliki daya hambat kuat. Namun, daya hambat yang dihasilkan dari ekstrak bawang putih masih belum mampu menghambat Klebsiella sp. sebaik antibiotik komersil., Klebsiella sp. is an infectious bacterium from the Enterobacteriaceae family that can infect both animals and humans. Garlic extract is used as an antibacterial alternative to minimize the use of commercial antibiotics. The research method is the re-identification test of Klebsiella sp. and garlic simplicia extraction. Antibacterial activity test is conducted in vitro to Klebsiella sp. using garlic extract with concentrations of 20%, 40%, 60%, 80%, and 100%. Analysis of research data is carried out using the Shapiro-Wilk test (normality) which showed that the data were not normally distributed. The test continued with Kruskal-Wallis to explain the significant difference (p < 0.05), the results of the Kruskal-Wallis test resulted in the diameter of the inhibition zone of Klebsiella sp. has p = 0.003 so p < 0.05, which means that garlic extract is able to work as an antibacterial against Klebsiella sp. Then continued the Mann-Whitney test to determine the difference in antibacterial activity of each test group. Garlic extracts with concentrations of 20% and 40% had moderate inhibition, while garlic extracts with concentrations of 60%, 80%, and 100% had strong inhibition. However, the inhibition power of garlic extract was not able to inhibit Klebsiella sp. better than commercial antibiotics.
Keyword: Antibakteri, Bawang putih, Ekstrak, Klebsiella sp., Uji in vitro, Antibacterial, Extract, Garlic, In vitro test

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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