Judul: Aktivitas Antibakteri dan Antioksidan Tiga Jenis Madu Hutan Indonesia
Abstrak: This study was conducted to determine the antibacterial and antioxidant activity of three types Indonesian forest honey, including honey forests of West Kalimantan (KB1), Sumatra (SM1) and Sumbawa (SB1). Antibacterial testing, was determined by sumur method with three concentration, ie 25%, 50% and 100% on four types of bacteria, Staphylococcus aureus, Salmonella typhi, Escherichia coli and Pseudomonas aeruginosa, while its antioxidant activity, was determined by DPPH (1-diphenyl-2-picrylhydrazil) method. The test results indicate that all three forest honey has antibacterial and antioxidant activity. SB1 forest honey has the best antibacterial activity specifically against S.thypi and E.coli with inhibitory diameter 32.5 mm dan 27.5 mm. In order of goodness with EC50 successively acquired KB1, SM1 and SB1 forest honey is 2725.722 ppm, 2872.765 ppm dan 4341.545 ppm. Antibacterial and antioxidant honey sourced from the content of one group of active compounds such as honey, alkaloids, phenolics, flavonoids, triterpenoids, saponins and glycosides.
Keyword: forest honey, antioxidant, antibacterial

Judul: Diastase Enzyme Activity and Antibacterial Effectiveness to Gastroenteritis by Apis mellifera Honey from Indonesia
Abstrak: Kualitas madu monoflora (Apis mellifera) sebagai antibakteri dapat dipengaruhi oleh aktivitas enzim diastase dan metabolit sekunder sumber nektar. Penelitian ini bertujuan untuk membandingkan aktivitas enzim diastase dan efektivitas madu monoflora yang berasal dari lebah Apis mellifera sebagai antibakteri alami terhadap bakteri Staphylococcus aureus, Escherichia coli, dan Salmonella typhi. Metode pengambilan sampel madu monoflora dari sembilan sumber nektar yang berbeda (akasia, kaliandra, rambutan, kayu putih, randu, mangga, kopi robusta 1, kopi robusta 2, dan karet) dilakukan dengan menentukan nilai diastase menggunakan spektrofotometri UV-Vis dan zona hambat bakteri menggunakan cakram difusi. Analisis multivariatif kadar brix, aktivitas enzim diastase, dan antibakteri menggunakan Principal Component Analysis (PCA). Hasil penelitian menunjukkan bahwa aktivitas enzim diastase tertinggi sebesar 20,00 DN pada madu mangga, rambutan, dan kopi robusta 2, sedangkan terendah sebesar 4,00 DN pada madu kaliandra. Aktivitas antibakteri terhadap S. aureus tertinggi sebesar 19,47 mm pada madu kopi robusta 2, terhadap E. coli sebesar 27,93 mm pada madu randu, dan terhadap S. typhi sebesar 18,53 mm pada madu kopi robusta 2. Nilai konsentrasi hambat minimum (KHM) tehadap bakteri yang diuji sebesar 8 µg/mL pada madu akasia, kayu putih, randu, kopi robsuta 1, dan kopi robusta 2. Analisis klasterisasi berdasarkan kadar brix, aktivitas enzim diastase, dan antibakteri yaitu klaster 1 (kaliandra); klaster 2 (akasia, kayu putih, randu, kopi robusta 1); klaster 3 (mangga, rambutan, kopi robusta 2); klaster 4 (karet)., The quality of monoflora honey (Apis mellifera) as an antibacterial can be influenced by the activity of the diastase enzyme and the secondary metabolites of the nectar source. This study aims to compare the activity of the diastase enzyme and the effectiveness of monoflora honey derived from Apis mellifera bees as a natural antibacterial agent against Staphylococcus aureus, Escherichia coli, and Salmonella typhi. The sampling method for monoflora honey from nine different nectar sources (acacia, calliandra, rambutan, eucalyptus, randu, mango, robusta coffee 1, robusta coffee 2, and rubber) was carried out by determining the diastase value using UV-Vis spectrophotometry and the bacterial inhibition zone using the diffusion disc. Multivariate analysis of brix content, diastase enzyme and antibacterial activity using Principal Component Analysis (PCA). The results showed that the highest diastase enzyme activity was 20.00 DN in mango, rambutan, and robusta coffee 2 honeys, while the lowest was 4.00 DN in calliandra honey. The highest antibacterial activity against S. aureus was 19.47 mm in robusta coffee 2 honey, against E. coli was 27.93 mm in randu honey, and against S. typhi was 18.53 mm in robusta coffee 2 honey. Minimum inhibitory concentration (MIC) values for the tested bacteria were 8 g/mL on acacia honey, eucalyptus, randu, robsuta coffee 1, and robsuta coffee 2. Clusterization analysis was based on brix content, diastase enzyme activity, and antibacterial activity, namely cluster 1 (calliandra); cluster 2 (acacia, eucalyptus, randu, robusta coffee 1); cluster 3 (mango, rambutan, robusta coffee 2); and cluster 4 (rubber).
Keyword: antibakteri, enzim diastase, madu Apis mellifera, antibacterial, diastase enzyme, Apis mellifera honey

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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