Judul: In Vitro Antibacterial Activity of Bird's Eye Chilli (Capsicum frutescens L.) Extract Against Escherichia coli Isolate from Cat
Abstrak: Cabai rawit (Capsicum frustescens L.) merupakan tanaman yang banyak ditemukan di Indonesia, dan diketahui memiliki banyak fungsi selain sebagai makanan. Penggunaan bahan tanaman herbal sebagai pengobatan alternatif sudah banyak digunakan sejak lama. Escherichia coli adalah bakteri Gram negatif yang merupakan flora normal usus manusia maupun hewan. Namun, dalam beberapa keadaan dapat menimbulkan penyakit yang cukup serius. Resistensi bakteri terhadap berbagai jenis obat menjadi suatu masalah yang cukup serius bagi dunia kedokteran hewan. Penelitian ini bertujuan untuk mengamati aktivitas antibakteri dari ekstrak cabai rawit terhadap isolat E. coli dari kucing secara in vitro. Ekstrak cabai rawit dibuat dengan metode maserasi dan pelarut etanol 96% dan pengujian antibakteri dengan metode difusi sumur. Didapatkan hasil bahwa ekstrak cabai rawit memiliki aktivitas antibakteri kategori lemah terhadap isolat E. coli asal kucing yang dilakukan secara in vitro., Bird’s eye chilli (Capsicum frutescens L.) is a plant that is can be found a lot in Indonesia and known has many other uses than just for food. Herbal plant has been used as an alternative medicine for a long period of time. Escherichia coli is a Gram-negative bacteria which a normal flora of human’s and animal’s gut. But in some condition, it can cause serious disease. Multidrug resistance is a serious problem to veterinary medicine. This study aimed to provide the in vitro antibacterial activity of bird’s eye chilli extract against E. coli isolate from cats. Extraction of bird’s eye chilli done by maseration with ethanol 96% as solvent, and the antibacterial test done by using well diffusion method. The result form this study is the extract of bird’s eye chilli has weak antibacterial activity against E. coli isolate from cat.
Keyword: antibacterial, bird's eye chilli, Capsicum, Escherichia coli

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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