Judul: IPB (Bogor Agricultural University)
Abstrak: Trehalosa adalah disakarida yang telah digunakan sebagai krioprotektan ekstraseluler dalam kriopreservasi sel. Trehalosa melindungi viabilitas sel dan menstabilisasi protein dalam kondisi lingkungan yang ekstrem. Penggunaan trehalosa sebagai krioprotektan intraseluler berpotensi menggantikan dimetil sulfoksida yang bersifat sitotoksik namun sangat efektif sebagai kriomedium intrasel. Penelitian sebelumnya mendapati bahwa pemuatan trehalosa difasilitasi oleh endositosis yang bergantung pada mikrotubulus namun tidak dipengaruhi kinerja aktin. Penentuan tipe endositosis yang memfasilitasi pemuatan trehalosa membutuhkan evaluasi lebih lanjut. Penelitian ini bertujuan memberikan bukti langsung tipe endositosis yang memfasilitasi pemuatan trehalosa pada sel manusia, khususnya pada sel fibroblas. Penelitian ini fokus pada penggunaan tiga inhibitor endositosis spesifik untuk membedakan endositosis berbasis clathrin dan yang tidak berbasis clathrin, yaitu pitstop-2, dynasore, dan cytochalasin D. Penelitian ini juga memberikan gambaran viabilitas sel progenitor mesenkim terhadap paparan trehalosa, bukti pemuatan trehalosa ke dalam sitoplasma fibroblast, dan upaya mengaplikasikan trehalosa sebagai krioprotektan intraseluler dan ekstraseluler dalam melindungi viabilitas dan fungsi perlekatan pada proses kriopreservasi sel fibroblas. Hasil penelitian menunjukkan bahwa paparan trehalosa aman terhadap sel progenitor mesenkim meski memiliki sifat sebagai osmolit, trehalosa dapat masuk ke dalam sitoplasma sel fibroblas dengan mekanisme pemuatan trehalosa yang dihambat secara signfikan oleh pitstop-2, dynasore, dan cytochalasin D (p<0.05). Hasil ini menjadi bukti langsung bahwa pemuatan trehalosa difasilitasi oleh endositosis berbasis clathrin. Meski demikian, tidak ada eksperimen yang berhasil sepenuhnya menghambat pemuatan trehalosa walaupun digunakan kombinasi inhibitor pitstop-2 dan dynasore sehingga diperkirakan mekanisme endositosis non-spesifik lain turut terlibat dalam pemuatan trehalosa.
Keyword: Trehalosa, Endositosis, Fibroblast, Kriopreservasi, Clathrin

Judul: IPB (Bogor Agricultural University)
Abstrak: Kondisi stres menyebabkan jumlah radikal bebas berlebih dan dapat menimbulkan kerusakan sel. Tubuh secara normal mempunyai mekanisme pertahanan terhadap radikal bebas yaitu antioksidan. Antioksidan berfungsi untuk menetralkan radikal bebas. Superoksida dismutase (SOD) adalah salah satu enzin antioksidan intrasel yang melindungi sel dari serangan radikal bebas. Salah satu antioksidan ekstrasel yang dapat melindungi sel dari serangan radikal bebas adalah a[alfa]-tokoferol.
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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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