Judul: Potensi antioksidan daun mahkota dewa (Phaleria macrocarpa (Scheff.) Boerl.)
Abstrak: Aktivitas antioksidasi ekstrak daun muda dan daun tua mahkota dewa telah dianalisis secara in vitro dan dibandingkan dengan aktivitas ekstrak daging buah mahkota dewa dan senyawa a-tokoferol. Daun dan daging buah mahkota dewa diekstraksi menggunakan etanol 70% secara refluks. Aktivitas antioksidasi ditentukan dengan cara mengoksidasi substrat asam linoleat dalam udara pada suhu 40 derajat celcius selama 7 hari dengan atau tanpa ekstrak.
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Judul: Penentuan daya inhibisi ekstrak air dan etanol daging buah mahkota dewa, Phaleria macrocarpa(Scheff)Boerl), terhadap aktivitas enzim tirosin kinase secara in vitro
Abstrak: Tirosin kinase berperan penting dalam mengatur pertumbuhan dan diferensiasi sel. Aktivitas berlebihan dari enzim ini akibat mutasi akan menyebabkan pertumbuhan sel menjadi tidak tekendali. Daging buah mahkota dewa (Phaleria marcrocarpa (Scheff.) Boerl.) merupakan tumbuhan yang secara tradisional digunakan sebagai obat. Penelitian ini menguji daya hambat dari ekstrak tanaman terhadap aktivitas tirosin kinase menggunakan teknik enzyme linked immunosorbent assay (ELISA) dan hasilnya dibandingkan dengan genistein (kontrol positif). Ekstraksi daging buah mahkota dewa dilakukan dengan menggunakan pelarut etanol 70%, akuademineral, dan air panas. Hasil menunjukkan bahwa ketiga ekstrak mengandung flavonoid, alkaloid, saponin, dan tanin. Toksisitas ekstrak etanol lebih tinggi dari ekstrak akuademineral dan air panas dengan nilai LC50 berturut-turut 542,42; 543,68; dan 548,62 ppm. Ekstrak akuademineral dan air panas menghasilkan daya hambat lebih besar daripada ekstrak kasar flavonoid (72,11%) dari penelitian sebelumnya. Daya hambat untuk ekstrak akuademineral, air panas, dan etanol masing-masing sebesar 78,38%; 73,52%; dan 63.61%. Ketiga ekstrak ini mampu menghambat aktivitas tirosin kinase lebih tinggi dari genistein (6,12%) pada konsentrasi 300 ppm. Maka ketiga ekstrak tersebut mempunyai potensi yang besar sebagai inhibitor enzim tirosin kinase.
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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