Judul: Isolasi dan Elusidasi Struktur Molekul Aktif dari Spons Laut Lamellodysidea herbacea asal Ujung Kulon
Abstrak: Penelitian bertujuan mengisolasi dan mengelusidasi struktur molekul aktif spons laut Lamellodysidea herbacea asal Ujung Kulon. Lapisan CH2Cl2 (4.05 g) memiliki aktivitas antibakteri terhadap bakteri S. aureus (20 mm) dan P. aeruginosa (12 mm) pada konsentrasi 100 g/cakram menggunakan metode difusi plat-agar. Lapisan CH2Cl2 direkristalisasi dengan CHCl3−Me2CO−MeCN menghasilkan senyawa 3 (C12H6O4Br6) dalam kelompok ruang monoklinik P21/n (Z = 4) yang diidentifikasi sebagai 2,3,4,5-tetrabromo-6-(3',5'-dibromo-2'-hidroksi fenoksi) fenol setelah dielusidasi dengan 1H NMR, UV-Vis, FTIR, dan kristal tunggal difraksi sinar-X. Senyawa 3 mempunyai konformasi seperti twist dengan sudut torsi 1 = 27.7 (6) ; 2 = 86.5 (5) dan sudut ikatan eter 117.5. Senyawa 3 menunjukkan aktivitas antibakteri Gram-positif S. aureus ATCC 6535 dan Gram-negatif K. pneumoniae. Senyawa 3 tidak menunjukkan aktivitas terhadap bakteri patogen Gram-negatif E.coli (resisten ampicillin) hingga konsentrasi 50 g/cakram. Toksisitas senyawa 3 terhadap embrio D. rerio adalah LC50 > 10 g/mL.
Keyword: antibakteri, Danio rerio, elusidasi struktur, kristalografi sinar-X, Lamellodysidea herbacea

Judul: Isolasi dan Elusidasi Struktur suatu Senyawa Alkaloid dari Spons Laut Indonesia Acanthostrongylophora ingens
Abstrak: Penelitian ini bertujuan melakukan isolasi dan mengelusidasi struktur suatu senyawa alkaloid dari spons laut Acanthostrongylophora ingens asal Kepulauan Seribu. Lapisan etil asetat (4.31 g) difraksionasi dan menghasilkan 12 fraksi A–L. Rekristalisasi fraksi C menghasilkan subfraksi C2 dan C3 yang digabung menjadi fraksi CG-0 karena memiliki tingkat kemurnian yang tinggi dengan selisih nilai Rf yang kecil. Sejumlah 0.6 mg subfraksi C3 dianalisis struktur mutlaknya menggunakan kristalografi sinar-X. Fraksionasi CG-0 menghasilkan subfraksi CG-3 yang dianalisis menggunakan spektrometrimassa resolusi tinggi dan spektroskopi resonansi magnet inti (NMR). Subfraksi C3 dan CG-3 kemudian diidentifikasi sebagai senyawa 7. Senyawa 7 merupakan manzamina A hidroklorida (C36H45N4OCl) yang memiliki fitur struktur unik seperti cincin β-karbolina dengan sistem cincin polisiklik kompleks. Konfigurasi mutlak senyawa 7 ialah 12R, 24S, 25R, 26R, 34 R serta geometri cis (Z ) pada C-32‒C-33 dan C-15‒C-16.
Keyword: Acanthostrongylophora ingens, alkaloid,, HRESIMS, kristalografi sinar-X, NMR

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
Keyword: