Judul: Penambatan Molekul Flavonoid dan Asam Fenolat Kurma (Phoenix Dactylifera) dengan Xantin Oksidase
Abstrak: Tengah. Kurma mengandung asam fenolat dan flavonoid yang memiliki kemampuan antioksidan dan dapat menginhibisi kerja xantin oksidase. Penelitian ini bertujuan mengetahui interaksi molekuler xantin oksidase oleh senyawa asam fenolat dan flavonoid kurma menghambat kerja xantin oksidase dalam memproduksi asam urat. Penelitian dilakukan dengan metode in silico yaitu penambatan terarah (site directed docking). Ukuran pusat penambatan yang digunakan dalam penelitian ini sebesar x = 26.569, y = 9.985, dan z = 113.088 dan volume penambatan sebesar x = 14, y = 14, dan z = 16. Penghambatan oleh senyawa golongan flavonoid dan asam fenolat yang dilakukan menghasilkan kekuatan inhibisi yang baik ditunjukkan dengan energi bebas Gibbs yang bernilai negatif. Senyawa dengan nilai energi bebas Gibbs tertinggi yaitu senyawa antosianin yaitu sebesar -7.3 kKal/mol, nilai tersebut lebih tinggi dari ligan pembanding allopurinol. Berdasarkan analisis ikatan yang terbentuk, senyawa terbaik dalam menginhibisi xantin oksidase yaitu asam siringat.
Keyword: Asam fenolat, flavonoid, kurma, penambatan molekuler, xantin oksidase

Judul: Active Fraction of Melastoma affine D. Don Fruit Extract as Inhibitor of Xanthine Oxidase
Abstrak: Gout atau penyakit asam urat adalah penyakit yang disebabkan oleh kadar asam urat darah yang tinggi yang menyebabkan penumpukan di bagian sendi. Pengobatan asam urat dengan allopurinol bertujuan menghambat kerja xantin oksidase yang berperan sebagai enzim pembentuk asam urat. Namun obat ini memiliki efek samping yang merugikan. Tanaman herbal adalah sumber alternatif yang dapat dijadikan sebagai obat asam urat yang lebih aman. Beberapa senyawa flavonoid telah dilaporkan sebagai inhibitor xantin oksidase. Buah harendong mentah (Melastoma affine D. Don) memiliki potensi sebagai inhibitor xantin oksidase karena mengandung total flavonoid yang tinggi. Tujuan dari penelitian ini adalah untuk mengisolasi dan mengidentifikasi senyawa flavonoid ekstrak etanol 70% buah harendong, juga aktivitasnya dalam menghambat xantin oksidase. Sampel diekstrak dengan etanol 70% dan difraksinasi dengan pelarut n-heksana, n-butanol, etil asetat, dan air untuk memperoleh fraksi n-heksana, n-butanol, etil asetat, dan air. Masing-masing fraksi diukur dengan menguji daya inhibisi terhadap xantin oksidase untuk mendapatkan fraksi aktif., Gout occurs when uric acid is high in blood and is accumulate in joint as uric acid crystal. Uric acid treatment by allopurinol aims to inhibit xanthine oxidase activity which has a role in synthezise of uric acid. However, this drug has bad side effect. Medicinal plant is alternative source that can be used as uric acid drug with no bad side effect. Some of flavonoid compounds from plant had been reported as inhibitor of xanthine oxidase. Melastoma affine unripe fruit has a potent as xanthine oxidase inhibitor because this sample has high total flavonoid compound. The aim of this research were to isolate and identify flavonoid compound of Melastoma affine fruit extract, as well as xanthine oxidase inhibitory activity. Sample was extracted by 70% ethanol and fractionated by n-hexane, n-butanol, ethyl acetate, and water solvents to gain n-hexane, n-butanol, ethyl acetate, and water fractions. Each fractions were determined by inhibition assay of xanthine oxidase to get the active fraction.
Keyword: flavonoid, Melastoma affine, xanthine oxidase, inhibitor

Judul: The Construction of Greedy SVP LLL Algorithm
Abstrak: A lattice is a set of all integer linear combination of a set of linearly independent vectors in ℝ𝑛���. The independent vectors are called bases of lattice. Any lattice can be generated from many bases, and these bases have the same cardinality. In the lattice, the most fundamental and renowned problem is the Shortest Vector Problem (SVP). SVP is a tracking problem of the shortest nonzero vector in a lattice with equivalent bases. In two dimensions, SVP problem has resolved exactly by Gauss’ algorithm. When the lattice dimension is higher than two, A.K. Lenstra, H.W. Lenstra and L. Lovasz gave a LLL algorithm to compute approximation of nonzero shortest vector in the lattice. Reduced bases solution obtained from LLL algorithm still be an approximation and has polynomial running time of arbitrary dimension which large enough. In 1994, Schnoor and Euchner modified this LLL algorithm as a new variant which later was named deep insertion LLL algorithm. This algorithm is a modified version of the LLL algorithm to the terms of the exchange step to improve the accuracy of output of LLL reduced bases and applying it to the subset sum problem. The purpose of this research are: (1) Reconstruct the LLL algorithm and deep insertion LLL algorithm using a geometric approach. (2) Construct a greedy SVP LLL algorithm. (3) Implement the three algorithms in a symbolic programming language, and evaluate them experimentally. A bases ℬ=[𝐛���1,𝐛���2,…,𝐛���𝑛���] in ℝ𝑚��� is called reduced LLL with parameter 𝛿��� if satisfies: (a) |𝜇���𝑗���𝑖���|≤12, for every integer 𝑖���,𝑗��� with 1≤𝑖���<𝑗���<𝑛���. (b)𝛿���‖𝜋���𝑗���(𝐛���𝑗���)‖2≤‖𝜋���𝑗���(𝐛���𝑗���+1)‖2, for 𝑗���=1,2,…,𝑛���−1,where 𝛿��� is a reduced parameter of real numbers with 14<𝛿���<1. The first requirement is the reduced basis 𝛿��� must “nearly orthogonal” and in its computation case, this requirement can be reached out by using the Gram-Schmidt’s orthogonalization. While the second requirement is called exchange step, or used to called as Lovasz condition. By using both of these requirements, then they establish the LLL algorithm. Then, Schnoor and Euchner modify the LLL algorithm based on the requirements of the exchange step called the deep insertion LLL algorithm, where the exchange step is based on the comparison of the projected vector in orthogonal complement [𝐛���1,𝐛���2,…,𝐛���𝑘���−1]⊥ after j-th reduction. To construct greedy SVP LLL algorithm, the requirements of the exchange step is based on purely by comparing norm of lattice 𝐛���𝑗��� with norm lattice 𝐛���𝑖��� for 𝑖���=1,2,3…,𝑗���−1. The process of insertion reduced vector after the exchange step also has done greedily. Then, we calculate the number of arithmetic operation in greedy SVP LLL algorithm for further analysis. The result of our exprimentation for three algorithms on the certain matrix size shows that the running time of the three algorithms increases propotional to the size of the matrix. The result also shows that by using 𝛿���=34 for the LLL algorithm and the deep insertion LLL algorithm, and the greedy SVP LLL algorithm which is a new variant made by using no parameter of 𝛿���, outperform of the other of two previous algorithm in terms of speed with the same output.
Keyword: LLL algorithm, LLL deep insertion algorithm, greedy SVP LLL algorithm