Judul: Synthesis and In Vitro Test of Porous Hydroxyapatite-Chitosan with Sol Gel Method.
Abstrak: Hidroksiapatit (HAp) memiliki sifat biokompatibilitas yang baik dengan tulang karena memiliki kesamaan komposisi kimia dengan tulang. Salah satu metode sintesis HAp adalah metode sol gel. Metode sol gel dapat digunakan untuk menghasilkan kristal HAp yang baik. HAp berpori dibuat dari kalsium yang diperoleh dari cangkang telur dengan penambahan asam fosfat dan kitosan. Penelitian dilakukan dengan ragam volume larutan kitosan yang ditambahkan, yaitu 30, 40, 50, dan 60 mL. Analisis sampel dilakukan dengan menggunakan difraksi sinar-X (XRD), mikroskop elektron payaran (SEM), dan spektrofotometer serapan atom (AAS). Pencirian dengan XRD terhadap HAp-kitosan yang telah dikalsinasi menunjukkan tidak ada puncak kitosan, hanya terdapat puncak milik HAp. Pencirian dengan SEM menunjukkan bahwa penghilangan kitosan melalui kalsinasi menghasilkan HAp dengan pori berukuran mikro. Uji in vitro menunjukkan bahwa terjadi penurunan konsentrasi kalsium setelah 6 hari perendaman sampel dalam larutan simulated body fluid (SBF). Penurunan ini disebabkan oleh pengendapan ion kalsium pada permukaan HAp berpori untuk membentuk kristal apatit.
Keyword: 

Judul: Sintesis dan Karakterisasi Hidroksiapatit Berpori dengan Porogen Kitosan
Abstrak: This research had been done the synthesis of porous hydroxyapatite (HA) by sol gel method. The precusor calcium using eggshells and H3PO4 as phosphate source. The ratio of HA-chitosan to synthesize porous HA are 90:10, 80:20, 70:30, 60:40, and 50:50 and variation of chitosan size are 0.26 μm and 625.45 μm. The phase and crystaline structure of sample characterized by X-Ray Diffractometer. The porous HA with variation of chitosan A and chitosan B showed the percentage of HA would be rised if researcher added more of chitosan compotition, except HA-chitosan A 80:20, HA-chitosan B 80:20 and 70:30 be decreased, but did effect not for chrystaline size. The functional groups of HA identified by Fourier Transform Infrared Spectroscopy. The functional groups of HA which detected by are OH-, PO43-, and CO32-. The morphological structure of sample analyzed by Scanning Electron Microscopy. The result of sampel HA had shown the porouses structure using chitosan as porogen however it was small about 0.29-0.46 μm with the form of porouses are small cyrcle and the ditribution of porouses are smooth.
Keyword: 

Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
Keyword: