Judul: Penapisan Senyawa Antibakteri dari Ekstrak Biji Hanjeli (Coix lacryma-jobi) terhadap Escherichia coli dengan Pendekatan Metabolomik.
Abstrak: Biji hanjeli (Coix lacryma-jobi) diduga mengandung senyawa antibakteri. Pada penelitian ini, senyawa antibakteri dalam ekstrak biji diidentifikasi menggunakan kromatografi cair spektrometri massa/spektrometri massa (LCMS/ MS) dan dikelompokkan menggunakan principal component analysis (PCA). Biji hanjeli diekstraksi dengan cara maserasi menggunakan beberapa pelarut, yaitu air, etanol 50%, etanol 96%, dan n-heksana. Aktivitas antibakteri diuji menggunakan metode cakram, Escherichia coli ATCC 25922 sebagai bakteri uji, tetrasiklin sebagai kontrol positif, dan dimetil sulfoksida 20% sebagai kontrol negatif. Ekstrak etanol 50% memiliki aktivitas penghambat E. coli tertinggi. Ekstrak tersebut selanjutnya diidentifikasi menggunakan LC-MS/MS dan senyawa yang diperoleh dikelompokkan menggunakan PCA. Berdasarkan hasil, senyawa tersebut yang diprediksi memiliki aktivitas sebagai antibakteri adalah asam 4-dodesil benzena sulfonat, dodesil sulfat, anhidrida asam asetat, dan asam L-malat.
Keyword: antibakteri, Coix lacryma-jobi, E. coli, LC-MS/MS, PCA

Judul: Isolasi Senyawa Antibakteri Da1u Biji Mahoni (Swietenin innhngoni Jacq)
Abstrak: Mahoni mempakan salah satu tuinbuhan yang banyak dikenal di Indonesia dan banyak dibudidayakan. Kayu mahoni dipergunakan untuk venir dekoratif, kayu lapis, mebel, panil, perkapalan, balok percetakan, barang kerajinan, barang bubutan, dan komponen musik, sedangkan kulit dan biji mahoni banyak digunakan sebagai obat secara tradisional. Secara tradisional, biji mahoni daun kecil (Swietenia mahagoni Jacq) berkhasiat sebagai obat tekanan darah tinggi, encok, eksim, masuk angin, malaria, demam, anemia, diare, dan disentri. Dalam penelitian ini dilakukan isolasi senyawa antibakteri dari biji mahoni. Dilakukan uji aktivitas antibakteri dari ekslrak heksana, metanol, etil asetat, dan fraksi etil asetat hasil kromatografi kolom biji mahoni untuk menghambat aktivitas bakteri dengan memperhatikan atail mengamati zona bening yang terbentuk pada media agar. Hasil uji aktivitas antibakteri ekslrak heksana terhadap bakteri Esclterichia coli mempunyai zona hambat yang lebih kecil dibandingkan pada bakteri st16stilis, sedangkan ekstrak metanol terhadap bakteri E. coli mempunyai zona hambat yang lebih besar dibandingkan pada bakteri substilis. Uji aktivitas antibakteri ekstrak etil asetat terhadap bakteri E. coli mempunyai zona hambat yang lebih besar dibandingkan pada bakteri substilis pada konsentrasi 1 %, 2 %, dan 3 %. Hasil uji aktivitas antibakteri menunjukkan ekslrak heksana, metanol, dan etil asetat mempu~~yaaik tivitas antibakteri mulai konsentrasi 1 % terhadap bakteri E. coli dan bakteri substilis. Fraksinasi eksttak etil asetat dengan kromatografi kolom menghasilkan 13 fraksi. Berdasarkan uji aktivitas antibakteri terhadap bakteri E, coli dan bakteri substilis, fraksi 4 mempakan fraksi paling aktif yang berpotensi sebagai senyawa antibakteri dan mengandung steroidltriterpenoid, alkaloid, dan flavonoid.
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Judul: The Effects of Variance of Interest rate to Variance of Annuity Future Values
Abstrak: Time value of money is a concept that refers to the difference of the value of money due to time difference. The value of money for present time would not be the same as the value of money in the future. The value of money for present time is called as Present Value (PV) of the money and the value of money for future time is called Future Value (FV) of the money. Determination the value of money, for present and future time, depends on the time and rate of return. The value of money is determined by several factors such as inflation, fluctuation of interest rates, and government policy in securities and taxation. Due to fluctuation of the value of money we need a FV formulation, it is useful for knowing whether an investment can be profitable or not, and this information is useful also in budget analysis. Annuity is defined as a series of payments made for a specific period. The payment, fixed or varied, can be made at the beginning or at the end of the period. Annuity paid at the beginning of the period is called annuity-due and annuity paid at the end of the period is called immediate annuity-certain. The accumulated value of the annuity after few years later is called as a final value or a future value. Burnecki et al. (2003) have discussed about the FV of a fixed-rate annuity in which payments are made according to the arithmetic or geometric series. They have also examined FV for annuities in which payments are made according to arithmetic or geometric series with random rates of interest. This paper examines FV for annuity-due in which payments are made according to arithmetic or geometric series with interest rates as a random variable, which is normal distribution ,  . Future value formula is expressed in recursive form. FV for annuity-due which payments are made according to the arithmetic or geometric series with random rates of interest is calculated by theoretical way and simulation way. The random rates of interest is denoted as k k i  i  , where k i an independent random variable; i is a constant and k  is a random variable which has normal distribution ,  . By using the determined parameters, a sequence of random rates of interest are generated for theoretical calculation. Meanwhile for the simulation, the random rates of interest is generated 1000 times for the simulation. The generated data give mean value, variance, and standard deviation. Moreover, error of mean value, variance, and standard deviation from the theoretical and simulation results are calculated. Error calculation uses Symmetric Mean Absolute Percentage Error (SMAPE). The smaller the value of SMAPE is the more accurate the simulation. The interest rate variances are varied from 0.000036 to 0.0001 to study the relationship between variance of rates of interest and variance of future value. The theoretical and simulation results show that when the variance of random rates of interest increases, then the variance of FV increases linearly. FV of the annuity-due in
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