Judul: Penapisan Awal Senyawa Antioksidan Dari Ekstrak Gelidiella acerosa
Abstrak: Salah satu kerusakan bahan pangan yang sering tetjadi selama penyimpanan dan pengolahan adalah terjadinya reaksi oksidasi lemak dalam bahan pangan sehingga menyebabkan menurunnya kualitas organoleptik dan nilai gizinya. Karena itu diperlukan pcnambahan antioksidan ke dalam bahan pangan tersebut. Selain digunakan dalam produk pangan, antioksidan juga dimanfaatkan sebagai suplemen untuk mengatasi proses oksidasi di dalam tubuh. Pada keadaan normal, secara fisiologis sel memproduksi radikal bebas sebagai konsekuensi logis reaksi biokimia dalam kehidupan aerobik. Pada saat ini, lingkungan yang tercemar yang berasal dari polusi udara, polusi air, bahan-bahan kimia, obat-obatan, pestisida, dapat merangsang timbulnya radikaI bebas dalam tubuh.
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Judul: Transglikosilasi enzimatik polifenol-X-glukosida dan pemanfaatannya sebagai senyawa antioksidan
Abstrak: Antioksidan telah lama dikenal manfaat dan kegunaannya dalam industri farmasi, kosmetik dan makanan. Penambahan antioksidan pada lemak maupun bahan pangan merupakan cara paling efektif untuk mencegah oksidasi lemak. Selama ini antioksidan yang umum digunakan adalah antioksidan sintetik seperti butylated hydroxy unisole (BHA) dan butylated hydroxy toluene (BHT). Namun penggunaannya semakin dikhawatirkan oleh masyarakat karena beberapa penelitian membuktikan adanya efek toksik dan karsinogenik terhadap tubuh manusia (Osawa et 1992). Sehingga akhir-akhir ini perhatian. terhadap antioksidan alami yang berasal dari tumbuh-tumbuhan semakin meningkat karena dianggap lebih baik dari antioksidan sintetik, khususnya bila ditinjau dari segi kesehatan. Antioksidan alami terdapat dalam banyak tumbuhan obat yang biasanya terdapat dalam bagian daun, buah, akar, batang, dan biji. Bagian tersebut umumnya mengandung senyawa fenol atau polifenol (Pratt, 1992). Telah lama dikenal bahwa beberapa senyawa polifenol dan turunannya memiliki aktivitas antibakteri, antioksidan, antimelanogenesis, dan antimutagen (Ahn et al., 1991; loku et al., 1992; Funayama et al., 1995). Schagai antioksidan, polifenol berperan dalam menangkap radikal bebas penyebab peroksidasi lipid yang dapat menimbulkan kerusakan pada bahan makanan. Selain itu menurut Sulistyo et al. (1998) senyawa antioksidan berfungsi mencegah kerusakan sel dan DNA akibat adanya senyawa radikal bebas.
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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