Judul: Biosensor based on immobilized glucose oxidase on chitosan nanoparticles in modified carbon pasta electrode by polyaniline nanofibers as biosensor applications.
Abstrak: Biosensor berbasis glukosa oksidase dikembangkan untuk mendeteksi glukosa secara lebih tepat, cepat, dan sensitif. Pengembangan biosensor yang dilakukan memanfaatkan enzim glukosa oksidase teramobil pada nanopartikel kitosan dalam elektroda pasta karbon termodifikasi. Penelitian bertujuan menentukan kondisi optimum untuk menghasilkan nanopartikel kitosan dan mengetahui karakteristik glukosa oksidase/elektroda pasta karbon termodifikasi. Hasil uji menunjukan kondisi optimum untuk membuat nanopartikel kitosan, yaitu pada volume 300 mL dan waktu sonikasi 10 menit. Penambahan polianilin pada glukosa oksidase/elektroda pasta karbon termodifikasi dapat meningkatkan arus. Glukosa oksidase/elektroda pasta karbon termodifikasi memiliki kondisi optimum pada pH 5.0 dan konsentrasi glukosa sebesar 20 mM. Daerah linier berada pada 0.6-1.8 mM dan nilai sensitivitas elektroda sebesar 0.20 mA/mM. Nilai Km dan Imaks pada sebesar 1.934 mM dan0.937 mA ditentukan dengan metode Lineweaver-Burk. Hasil penelitian ini akan digunakan selanjutnya untuk pengembangan biosensor glukosa., Biosensor based on glucose oxidase enzyme has been developed to detect glucose levels more precise, rapid, and sensivity. The development of biosensor was used glucose oxidase immobilized on chitosan nanoparticles in modified carbon paste electrode. The purpose of this study were to determine the optimum condition in order to produce chitosan nanoparticles and to obtain characteristic of glucose oxidase/modified carbon pasta electrode. The result showed that optimum conditions were obtained to make chitosan nanoparticles with 300 mL of volume and 10 minutes of ultrasonication time. The addition of polyaniline on glucose oxidase/modified carbon pasta electrode increased the current. Glucose oxidase/modified carbon pasta electrode had optimum conditions at pH 5.0 and glucose concentration was 20 mM. Linier range was 0.6-1.8 mM dan sensitivity value of electrode was 0.20 mA/mM. Km and Imax value were 1.934 mM was 0.937 mA determined by Lineweaver-Burk method. These result will be further used for development of glucose biosensor. Key words: glucose biosensor, glucose oxidase, chitosan nanoparticles, polyaniline.
Keyword: biosensor glukosa, glukosa oksidase, nanopartikel kitosan, polianilin

Judul: Biosensor Kolesterol Berbasis Amobilisasi Kolesterol Oksidase pada Pasta Karbon Termodifikasi Nanoserat Polianilin.
Abstrak: Polyaniline nanofibre was found to increase the activity of the enzyme glucose oxidase in glucose biosensors. Therefore, this study aims to examine the effects of the usage of polyaniline nanofibre as electrode on the amobilized cholesterol oxidase activity. Research methods include synthesis and characterization of polyaniline nanofibre, cyclic voltammogram measurement of carbon paste electrodes (CPE) and a modified carbon paste electrodes (MCPE), immobilization of enzymes, as well as the optimization of the electrode working conditions. The result, MCPE, as immobilization media of cholesterol oxidase with glutaraldehyde as crosslinking agent, can detect levels of cholesterol in hypocholesterolemia conditions (normal <200 mg/dL). Sensitivity of sensor is 2.34 mA/mMcm2 at pH 8 and temperature of 45oC. Affinity of substrate-enzyme is also high with Km and Imax of 2.38 mM and 6.15 mA respectively. Beside that, the surface concentration of 0.002 mol/cm2 so generated MCPEChod+Glu could be potentially as cholesterol biosensor.
Keyword: biosensors, cholesterol, cholesterol oxidase, electrodes, polyaniline

Judul: Truncated Stop Loss as a Optimal Solution of Reinsurance Agreement in One-Period Model
Abstrak: Reinsurance is one of risk management efforts of an insurance company, which is called the cedent. Similar with insurance, reinsurance constitutes the cedent to pay the premium. We consider one-period reinsurance model and derive a rule which minimizes the ruin probability of the cedent for a fixed reinsurance premium. Therefore, it is needed to construct an optimal reinsurance agreement for the cedent. The premium is calculated according to four different principles, i.e. economic, generalized zero-utility, Esscher, and mean-variance principles. Stop loss is a reinsurance contract which protect the insurance company for losses that exceed a certain amount. The result of this research shows that a truncated stop loss is an optimal agreement in the class of all reinsurance contracts with various premiums calculated using above mentioned principles.
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