Judul: Sintesis dan Aplikasi Fase Diam Kromatografi Kolom Berbasis Selulosa-g-AAm: Variasi Penaut-Silang
Abstrak: Ela merupakan bahan lignoselulosa yang masih mengandung pati. Pati dalam ela dihidrolisis dengan HCl 3% dan lignin dihilangkan dengan H2O2 1.5% pH 12. Selulosa ela dimodifikasi melalui metode pencangkokan-penautan-silang dengan menggunakan inisiator amonium persulfat, monomer akrilamida (AAm), dan penaut-silang N,N’-metilena bis-akrilamida yang divariasikan sebanyak 0.5, 1.0, dan 2.0 g. Terbentuknya kopolimer cangkok-taut-silang ditunjukkan dengan spektrum inframerah transformasi Fourier yang memperlihatkan semua pita serapan khas selulosa maupun AAm. Kopolimer selulosa-graft-akrilamida (selulosa-g-AAm) yang terbentuk diaplikasikan sebagai fase diam kromatografi kolom untuk memisahkan senyawa kurkuminoid dan komponen nonpolar, yang salah satunya adalah xantorizol, dari ekstrak temu lawak. Analisis kualitatif dengan kromatografi lapis tipis menunjukkan bahwa selulosa-g-AAm dengan penaut-silang 1.0 dan 2.0 g memiliki kemampuan pemisahan senyawa kurkuminoid yang lebih baik daripada selulosa-g-AAm dengan penaut-silang 0.5 g. Pemisahan komponen nonpolar ekstrak temu lawak pada seluruh kopolimer cenderung tidak jauh berbeda.
Keyword: starchy lignocellulosic material, grafting-crosslinking method, cellulose-graft-acrylamide, Qualitative analysis, Ela

Judul: Sintesis Fase Diam Selulosa-g-AAm dengan Berbagai Kadar Penaut-silang sebagai Media Separator Xantorizol dari Ekstrak Temu Lawak
Abstrak: Rice straw in Indonesia is abundant and its cellulose can be modified to alter its characteristic. One of modification is by grafting-cross-linking method. The products will have a molecular structure that can be applied in separation technology. This research consists of three stages. The first stage was cellulose isolation, followed by cellulose-g-acrylamide synthesis at various amount of cross-linker (0.1, 0.5, and 1.0 g), and the last stage was application of the products as stationary phase. The success of isolation process was indicated by 0.81% residual lignin and increasing of alpha cellulose to 31.22%. Grafting-cross-linking process was indicated by increase of N and decreases of water absorption capacity in line with the increase of cross-linker amount. Functional group analysis showed some the characteristic bands, especially in wave number of 1674 cm-1, showing C═O of amide. All products were then applied on the column chromatography as stationary phase for separating xanthorrhizol. Based on thin layer chromatography profile, xanthorrhizol was always found in hexane fraction. However, all of copolymer tend to show similar performances. All samples can be reused twice for separation process.
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Judul: Dynamical System of Hepatitis B in Three Groups with Vaccination
Abstrak: The aim of this study is to modify the hepatitis B transmission model in three age groups involving vaccination from the model conducted by Zhoe and Zhang.The method used is to analyze the stability of the fixed point and its basic reproduction number (R_0). Performed stability analysis and numerical simulation to see population dynamics. Next, a sensitivity analysis of the parameters was carried out to see its effect on R_0. From the analysis obtained two fixed points, namely non-endemic and endemic fixed points. Non-endemic fixed points are locally asymptotically stable if R_0 <1 Meanwhile, the endemic fixed point is locally asymptotically stable if R_0 > 1. Hepatitis vaccination affects the number of susceptible population, because the more successful the vaccination, the smaller the number of susceptible populations so that the smaller the population will be infected.
Keyword: Dynamic, Hepatitis B, Vaccine, Mathematical model