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 of Coriander Seed (Coriandrum sativum) Extract against Escherichia coli Isolate from Chicken.
Abstrak: Escherichia coli merupakan bakteri gram negatif. Bakteri ini adalah flora normal pada manusia dan hewan. Namun, beberapa kondisi seperti pertumbuhan bakteri yang berlebihan dapat menyebabkan penyakit yang sangat serius. Ketumbar (Coriandrum sativum) merupakan tanaman yang terdapat di Indonesia dan umumnya dipakai sebagai bumbu masakan. Namun ketumbar juga dapat digunakan dalam pengobatan alternatif. Penelitian ini bertujuan untuk mengetahui aktivitas antibakteri ekstrak ketumbar secara in vitro terhadap isolat E. coli dari ayam. Ekstraksi ketumbar menggunakan metode maserasi dengan pelarut etanol 96%, dan uji antibakteri dilakukan dengan metode difusi sumur agar dengan konsentrasi 100%, 80%, 60%, 40%, 20%, dan 10%. Hasil penelitian ini ekstrak ketumbar tidak menunjukkan aktivitas antibakteri terhadap isolasi E. coli dari ayam. Hasil ini diduga karena kandungan bahan aktif ekstrak biji ketumbar tidak mencukupi, ekstrak biji ketumbar memiliki daya difusi yang kurang baik, bahan aktif biji ketumbar yang tidak larut dengan sempurna, dan resistensi E. coli., Escherichia coli is a gram negative bacterium which is a normal flora in humans and animals. However, some conditions such as bacterial overgrowth can lead to very serious illnesses. Coriander (Coriandrum sativum) is a plant found in Indonesia and is generally used as a cooking spice. However coriander can also be used as an alternative medicine. This study aimed to determine the antibacterial activity of coriander extract in vitro against E. coli isolates from chickens. Coriander extraction used maceration method with 96% ethanol solvent, and antibacterial test was carried out by agar-well diffusion method with concentrations of 100%, 80%, 60%, 40%, 20%, and 10%. The result of this study coriander extract did not show antibacterial activity against the isolation of E. coli from chicken. This result was presumed because the active ingredient of the coriander seed extract was insufficient, coriander seed extract had poor diffusion power, the active ingredient of coriander seed did not dissolve completely, and E. coli resistance.
Keyword: antibacterial, Escherichia coli, coriander

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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