Judul: Antioxidant Activity and Bioactive Compound of Rhizophora mucronata as herbal tea preparations
Abstrak: Rhizophora mucronata merupakan jenis mangrove yang banyak dijumpai di Indonesia. R. mucronata memiliki kandungan senyawa bioaktif yang potensial untuk dimanfaatkan untuk menangkal radikal bebas. Penelitian ini bertujuan menentukan senyawa bioaktif serta aktivitas antioksidan yang terkandung dalam daun, bunga dan buah R. mucronata. Penelitian meliputi karakterisasi daun, bunga dan buah segar serta kering, serta menentukan kandungan fitokimia, total fenol dan aktivitas antioksidan ekstrak R. mucronata. Ekstrak bunga memiliki aktivitas antioksidan tertinggi 55,21±5,156 mg asam askorbat/g ekstrak dan total fenol tertinggi 2,44±0,354 mg/g. Kandungan senyawa bioaktif pada ekstrak bunga yaitu fenol, saponin, flavonoid, tanin dan triterpenoid., Rhizophora mucronata is one type of mangrove plant that grows in Indonesia. Bioactive compound in R. mucronata has potential to use against reactive species. The purpose of this study were to determine bioactive compound and antioxidant activity in leaves, flowers and fruits of R. mucronata. This study includes characterization of fresh and dried leaves, flowers and fruits and determining phytochemical content, total phenolic and antioxidant activity from extract of R. mucronata. Flowers exctract has the highest antioxidant activity 55.21±5.156 mg ascorbic acid/g extract and highest phenolic total 2.44±0.354 mg/g. Flowers extracts has bioactive compound content such as phenol, saponin, flavonoid, tanin and triterpenoid.
Keyword: antioksidan, Rhizophora mucronata, total fenol

Judul: Potensi Ekstrak Rhizophora sp. sebagai Inhibitor Tirosinase
Abstrak: Rhizophora sp. is one of plant type that has benefit as medicinal plants, for example, as whitening agent. The purpose of this study is to discover the parts and species of Rhizophora sp. which have best tyrosinase inhibitory activity. Leaves, stems, and roots of R. mucronata and R. stylosa were extracted with methanol and were tested their activities in order to obtain the best tyrosinase inhibitory activity. Based on the results, extracts of leaves, stems, and roots of R. mucronata from Tritih, Cilacap; Gebang, Cirebon; Eretan Kulon, Indramayu; Ujung Negoro Beach, Batang; Sigundu Beach, Batang; and Kapuk Beach, Jakarta were not potencial as tyrosinase inhibitor. Tyrosinase inhibitor activity from roots of R. mucronata from Samboja, East Kalimantan was higher than from its leaves and stems, especially for monophenolase with IC50 15.34 μg/ml. In perponderonce with, tyrosinase inhibitor activity from stems of R. stylosa from Samboja, East Kalimantan was also higher compared with stems of R. mucronata with IC50 38.02 μg/ml.
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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