Judul: Pengaruh Asam Jawa (Tamarindus iindica L.) dan Kombinasi dengan Bawang Putih (Allium sativum Linn) terhadap Pertumbuhan Beberapa Bakteri Patogen
Abstrak: Penelitian ini bertujuan untuk mempelajari pengaruh asam jawa terhadap pertumbuhan beberapa bakteri patogen, yaitu Escherichia coli. Salmonella typhimurium, dan Staphylococcuc aereus. Selain itu juga dilihat pengaruh penanaman bawang putih 2% terhadap berbagai konsentrasi asam jawa dan pengaruh pemanasan terhadap bumbu tersebut.
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Judul: Aktivitas antimikroba ekstrak jahe (Zingiber officinale Roscoe) terhadap beberapa bakteri patogen
Abstrak: hazards to the human health. Ginger (Zingiber officinale Roscoe) is commonly used as traditional medicine. It has a potential as antimicrobial agent by inhibit or kill microbes in dose dependent manner. The principle compounds of ginger are essential oils and non volatile compounds which maximum have antimicrobial activity. The objectives of this research are: (1) to study the yield of ginger extracts by multistage maceration with different polarity solvents, (2) to study antimicrobial activity of hexane, ethyl acetate and ethanol extract of ginger against foodborne pathogen such as Staphylococcus aureus, Bacillus cereus and Salmonella enterica serovar Typhimurium. Ginger extracts were prepared by multistage maceration method using solvent hexane, ethyl acetate and ethanol. The ginger extracts were assayed for antimicrobial activity by agar well diffusion method with Diameter Inhibition Zone (DIZ) and dillution broth method. The yield of hexane, ethyl acetate and ethanol ginger extracts from multistage maceration were respectively 3,57; 3,17; 3,02 g/100 g dry ginger. The DIZ value for Staphylococcus aureus were 5,0; 5,7; 1,3 mm with hexane, ethyl acetate and ethanol ginger extracts respectively 6,1; 6,6; 6,0 mm for Bacillus cereus and Salmonella Typhimurium were show no inhibitory zone. This results showed that the ginger extracts from multistage maceration have a weak antimicrobial activity (1,3 – 6,6 mm) against Gram-positive bacterial. The inhibition activity was determined for ethyl acetate ginger extract that showed the relatively highest inhibition zone. The minimum inhibition concentration did not reach in a range concentration between 5 – 20 mg/ml against Staphylococcus aureus and Bacillus cereus, therefore ginger extracts from multistage maceration with rotavapor temperature 50 o C and freeze dry process were not efficient to developed as natural antimicrobial.
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Judul: Best Difference Equation Aproximation to Duffing 's Equation
Abstrak: Persamaan Duffing merupakan persamaan yang sering muncul sebagai model masalah sistem ayun mekanis atau pada masalah rangkaian listrik. Umumnya penyelesaian persamaan ini secara numerik memberikan hampiran dengan gala! yang tinggi, seperti dengan metode Runge-Kutta. Tulisan ini mengkonstruksi suatu persamaan beda untuk menghampiri persamaan Duffing tersebut. Penyelesaian dari persamaan beda ini melibatkan fungsi-fungsi eliptik Jacobi. Berdasarkan penyelesaian ini diperoleh basil bahwa penyelesaian hampirannya persis sama dengan penyelesaian analitiknya. Penyelesaian analitik yang diperolehjuga melibalkan fungsi-fungsi eliptik Jacobi.
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