Judul: Characterization of Antibacterial Properties in Peptide  Filtrate from Commercial Dadih Collected at Varied bamboo
Abstrak: Dadih adalah produk fermentasi susu tradisional yang berasal dari Sumatera Barat, dibuat dari susu kerbau melalui fermentasi alami dalam bambu. Dadih ber potensi menghasilkan peptida bioaktif, salah satunya peptida antibakteri. Penelitian ini bertujuan untuk karakterisasi sifat antibakteri dari filtrat peptida yang didapat dari dadih komersial dengan ukuran bambu berbeda. Metode yang dilakukan yaitu, filtrasi peptida dengan cutoff 3 kDa, pengukuran pH, total asam teritrasi, kadar protein (Lowry), dan pengujian antibakteri dengan Staphylococcus aureus, Bacillus cereus, Escherichia coli, dan Salmonella typii. Hasil penelitian menunjukkan ukuran bambu berbeda tidak memiliki pengaruh yata (P>0,05) terhadap kadar protein, pH, dan total asam pada dadih. Ukuran bambu berbeda tidak berpengaruh nyata (P>0,05) terhadap daya hambat antibakteri dadih pada bakteri Gram positif. Namun, memiliki pengaruh nyata (P<0,05) terhadap daya hambat antibakteri dadih pada bakteri Gram negatif yaitu E. coli dan S. typii. Hal ini menunjukkan aktivitas antibakteri dadih lebih berpengaruh terhadap bakteri Gram negatif karena produksi senyawa-senyawa antibakteri yang berbeda pada setiap bambu.
Keyword: dadih, antibakteri, bambu, filtrat peptida

Judul: Anticancer Characterization of Commercial Dadih Peptide Against MCF-7 Cancer Cells by In Vitro
Abstrak: Dadih adalah produk susu fermentasi tradisional yang berasal dari Sumatera Barat, yang diproduksi melalui fermentasi alami susu kerbau dalam tabung bambu. Selama proses fermentasi dadih, bakteri asam laktat (BAL) mendominasi proses proteolisis. Sementara itu sudah banyak penelitian yang dilakukan pada bioaktivitas peptida namun, penelitian masih terbatas mengenai sifat antikanker yang dimilikinya. Penelitian ini bertujuan untuk menganalisis sifat antikanker pada dadih dengan dan tanpa filtrasi dadih terhadap sel kanker MCF-7. Sampel dadih didapatkan dari penjual komersial dari Kota Padang. Filtrasi dilakukan dengan menggunakan filtrasi Amicon dengan 3000 MWCO. Konsentrasi protein dari dadih dengan dan tanpa filtrasi diuji dengan menggunakan metode Lowry yang menunjukkan bahwa dadih yang di filtrasi memiliki konsentrasi protein yang lebih sedikit dibandingkan dengan dadih non filtrasi. Selanjutnya, aktivitas antikanker pada dadih dilakukan secara in vitro dengan MTT Assay yang menunjukkan bahwa nilai IC50 dari kedua sampel dianggap sebagai antikanker yang kuat. Tetapi, dadih non filtrasi menunjukkan aktivitas penghambatan yang lebih baik dibandingkan dengan dadih yang di filtrasi berdasarkan nilai IC50., Dadih is a traditional fermented milk product originating from West Sumatra, produced through the natural fermentation of buffalo milk within bamboo tubes. During fermentation, lactic acid bacteria (LAB) dominated the process by not only producing lactic acid, but also peptides from proteolysis process. While many studies were conducted on bioactivity of these peptides, limited studies were conducted on their anticancer properties. This study aimed to analyze the anticancer properties of dadih with and without peptide filtration against MCF-7 cancer cells. Dadih samples will be collected from commercial vendors in Padang. Filtration was done using Amicon filtration with 3000 MWCO. Concentration of protein from unfiltered and filtered dadih were tasted using Lowry method which indicated that filtered dadih has significant less protein as compared to non-filtered dadih. Further, anticancer activity was also done in vitro with MTT Assay which indicated that IC50 value of both samples were considered to be strong anticancer. But the non-filtered dadih exhibited better inhibition activity as compared to filtered one based on their IC50 values.
Keyword: Antikanker, dadih, sel MCF-7, peptida

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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