Judul: Short chain fatty acid (SCFA) profile produced by Clostridium butyricum grown on medium containing type 3 resistant starch (RS3) of sweet potato
Abstrak: Gastrointestines is an important part of body metabolism which affects human health. One of the deseases which attack gastrointestines is colorectal cancer (CRC) which can be prevented by proper lifestyle and consumption of healthy functional food. SCFA are the main products of anaerobic microbial fermentation in the large intestine and affect colonic health by providing energy to the epithelial cells. The organic acids produced in the colon are acetic acid, propionic acid, and butyric acid. Interest in butyrate role as a possible protective agent has arisen from its anti-proliferative effects on cells in vitro including colon tumour cell lines. Resistant starch (RS), is retrogradaded starch that escapes digestion in the small intestine and can be fermented in colon by anaerobic bacteria producing SCFA which contributes to the gastrointestinal health, and thus can be classified as funtional food. The crystalline non-granular starch (RS3) can be obtained from many starchy sources, such as rice, corn, maize, wheat, sago, banana, potato, and sweet potato. In this study, jago sweet potato used contain 31% starch content. Jago sweet potato is usually consumed indirectly as the taste is not preferable.
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Judul: Toksisitas Short Chain Fatty Acid (SCFA), Produk Turunan Pati Resisten Tipe 3 Hasil Fermentasi Ubi Jalar (Ipomoea batatas) Oleh Bakteri Clostridium butyricum BCC B2571 Terhadap Sel HCT-116
Abstrak: Sweet potato (Ipomoea batatas) is a food that contains high type 3 resistant starch. Fermentation of type 3 resistant starch by several bacteria such as Clostridium can produce Short Chain Fatty Acid (SCFA) containing acetate, propionate, and butyrate. SCFA butyrate is capable to inhibit the growth of colon carcinoma cells with an apoptosis pathway. The aim of this research was to analyze the toxicity of SCFA produce from fermentation of type-3 resistant starch from sweet potato with the bacterium Clostridium butyricum BCC B2571 against human colon carcinoma cell line using hemacytometer cell counting method and detection of apoptotic cells by Hoechst 33258 staining. The type 3 resistant starch fermented from sweet potato with a molar ratio of acetate, propionate, and butyrate at 52.95 mM : 66.93 mM : 92.41 mM were used as the primary working solution which was further diluted. VERO cell was used in the analysis as a normal cell with treatment given at concentration of 10 mM; 5 mM: 2.5 mM: 1.25 mM: 0.625 mM, while HCT 116 cells was used as a colon cancer cells by treatment with 1.25 mM; 0.625 mM: 0.313 mM: 0.156 mM; 0.078 mM. The results showed that the butyrate concentration of 1.25 mM showed the high toxicity of 85.42% to HCT 116 cells and in VERO cells showed low toxicity at 46.97%. Detection of apoptosis using Hoechst 33258 staining showed that apoptosis occurred in HCT-116 cells by a SCFA concentration of 1.25 mM and 0.625 mM.
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Judul: Metode Numerik Untuk Menentukan Harga Opsi Dengan Model Volatilitas Leland.
Abstrak: Salah satu hal penting dalam perdagangan opsi adalah penentuan harga jual yang optimal. Teori penentuan harga opsi telah dikembangkan pada tahun 1973 oleh Fisher Black dan Myron Scholes yang berhasil merumuskan masalah penentuan harga opsi ke dalam bentuk persamaan diferensial parsial (PDP) Black Scholes. Model Black scholes menggunakan beberapa asumsi, yang salah satunya adalah tidak terdapat biaya transaksi. Model Black scholes tidak relevan sebab pada kenyataannya terdapat biaya transaksi di pasar saham. Dengan memasukkan biaya transaksi ke dalam model, Leland menunjukkan bahwa persaman diferensial parsial (PDP) Black Scholes berubah menjadi persamaan diferensial parsial taklinear. Selanjutnya dengan mengasumsikan biaya transaksi proporsional dengan nilai uang dari aset yang dijual atau dibeli, Leland memodifikasi persamaan diferensial parsial (PDP) Black Scholes standar menjadi persamaan diferensial parsial (PDP) Black Scholes taklinear. PDP tak linier tersebut tidak mempunyai solusi analitik sehingga dibutuhkan pendekatan metode numerik untuk menentukan solusi hampirannya. Pada penelitian ini digunakan metode beda hingga upwind untuk diskretisasi ruang (harga saham) serta diskretisasi eksplisit dan implisit untuk diskretisasi waktu. Pada penelitian ini dapat terlihat bahwa penggunaan metode beda hingga upwind akan konvergen ketika menggunakan skema diskretisasi implisit terhadap waktu. Skema diskretisasi ini terbukti monoton, konsisten dan stabil. Berdasarkan hasil dari simulasi numerik, telah ditunjukkan bahwa orde kekonvergenan untuk metode beda hingga upwind dengan model volatilitas Leland adalah sekitar 1.80 untuk opsi Call, 1.80 untuk opsi Put , 1.35 opsi Cash or Nothing, serta 1.84 untuk opsi Butterfly.
Keyword: Harga opsi, Kekonvergenan, Metode beda hingga upwind, Model volatilitas Leland, Persamaan differensial parsial takliniear