Judul: Daun Ki Pahit (Tithonia diversifolia) sebagai Sumber Antibakteri dan Antioksidan
Abstrak: Antibacterial and antioxidant analysis have been assayed on extracts and essential oil of ki pahit leaves (Tithonia diversifolia). The antibacterial activity was tested toward Staphylococcus aureus and S. epidermidis, and the antioxidant activity was assayed toward 1,1-diphenyl-2-picryl hydrazyl (DPPH). The most active extract was the residual methanol extract with minimum inhibitory concentration (MIC) values against S. aureus and S. epidermidis were 1.00 and 2.00 mg/mL, respectively, the minimum bactericidal concentration (MBC) value >2.00 mg/mL, and the inhibition of 50% DPPH, IC50 was 27.88 μg/mL. The residual methanol extract was fractionated using column chromatography to obtain 13 fractions. F1 was the most active fraction with MIC values against S. aureus and S. epidermidis with 0.25 and 1.00 mg/L and MBC values were 0.50 and 2.00 mg/mL, respectively. The IC50 of the antioxidant was 22.88 μg/mL. The F1 fraction was further fractionated by thin layer chromatography to obtain 11 fractions. The F1.2 fraction was the most active fraction as indicated by inhibition the growth of S. aureus and S. epidermidis that of 0.25 and 0.50 mg/mL and indicated by killing the bacteria that of 0.50 and 2.00 mg/ml, respectively, and 50% DPPH that could inhibit was 30.94 μg/mL. Based on identification using ultraviolet-visible and fourier transform infrared spectrophotometers, the active compound was indicated to be in auron group.
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Judul: Observasi Potensi Penggunaan Daun Mengkudu (Morinda citrifolia L.) sebagai Antibakteri, Antioksidan dan sumber β-Karoten.
Abstrak: Penelitian ini bertujuan untuk mengobservasi potensi penggunaan daun mengkudu (Morinda citrifolia L.) sebagai antibakteri, antioksidan, dan sumber β- karoten. Daun mengkudu diolah dengan empat metode pengolahan sederhana yaitu penepungan, blending, juicing dan dekokta. Tepung daun mengkudu menghasilkan kandungan senyawa aktif steroid dan triterpenoid yang sangat kuat dan diduga bersifat antibakteri. Ekstrak tepung daun mengkudu yang dimaserasi selama 48 jam tidak mampu menghambat bakteri Escherichia coli, namun mampu menghambat bakteri Salmonella typhimurium. Zona hambat terhadap bakteri Salmonella typhimurium adalah 2.4 mm, 5.4 mm, and 15.4 mm pada pelarut etanol masing-masing pada konsentrasi 2.5%, 5%, and 10%. Kemudian, sebesar 3.4 mm, 5.4 mm, 7.4 mm, 12.4 mm, pada pelarut etil asetat masing-masing pada konsentrasi 2.5%, 5%, 7.5%, and 10%. Konsentrasi 7.5% pada pelarut etanol tidak memiliki zona hambat. Tepung daun mengkudu memiliki kandungan β-karoten sebesar 0.81 % atau 8100 ppm dengan aktivitas antioksidan sebesar 31%, sehingga daun mengkudu dapat berpotensi sebagai antibakteri, antioksidan, dan sumber β-karoten.
Keyword: antibakteri, antioksidan, β-karoten, daun mengkudu

Judul: Selang kepercayaan untuk koefisien B1 dari garis regresi apabila ragam galat tidak homogen dengan metode ols, wls dan bootstrap
Abstrak: Slope estimation of a regression line and its confidence interval can be constructed by OLS (Ordinary Least Squares) and WLS (Weighted Least Squares) method. Confidence interval being found by both method must satisfy assumption about normality of error term with zero mean and common variance for OLS method and heteroscedasticity for WLS method and independency of error term. NC (Nanayakkara and Cressie) method is a method aimed to reduce variance of estimate resulted from OLS method when error term has non- constant variance.
Keyword: Percentite-bootstrap, Ordinary Least Squares, Weighted Least Squares