Judul: Aktivitas Antibakteri Ekstrak Daun Bakau Hitam Rhizophora mucronata terhadap Bakteri Penyebab Diare
Abstrak: Diarrhea is one of the major health problems in Indonesia. One of the first caused is bacteria. Leaves of Rhizophora mucronata have been widely used by coastal people as folk medicine for treating diarrhea. The aims of this study was to determine the effectivity and inhibitory of Rhizophora mucronata leaf extract as antibacterial to diarrhea-causing bacteria. The procedure of this research used antibacterial assay determined by agar well diffusion method. The activity of each extract was tested by using diarrhea-causing bacteria. Methanol extract of R. mucronata leaf was the highest yield (21.47%). The active compounds of methanol and aqueous extracts consisted of tannin, saponin, flavonoid, phenol hydroquinone, and triterpenoid. Alkaloid was only showed in methanol extract. Methanol extract had the highest antibacterial activity with inhibition zone of 3-12 mm. Minimum inhibitory concentrations of methanol extract were 0.4 mg/mL (Escherichia coli dan Pseudomonas aeruginosa), 0.2 mg/mL (Staphylococcus aureus), and more than 0.4 mg/mL (EPEC dan Salmonella typhimurium). Bioautography of antibacterial activity toward E. coli revealed the active fractions with Rf value of 0.11 and 0.72. Preliminary identification using Dragendorff spray reagent detected the active compound was alkaloid
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Judul: Aktivitas Buah Bakau Rhizophora stylosa Griff. sebagai Antidiare secara In Vitro
Abstrak: Diare merupakan masalah kesehatan utama yang disebabkan oleh bakteri. Buah bakau (R. stylosa) telah banyak dimanfaatkan oleh masyarakat sebagai obat tradisional. Penelitian ini bertujuan mengetahui efektivitas dan daya hambat ekstrak buah bakau (R. stylosa) terhadap bakteri penyebab diare. Metode penelitian yang digunakan adalah metode sumur agar. Hasil penelitian menunjukkan bahwa rendemen ekstrak metanol merupakan rendemen tertinggi dari ekstrak lainnya dengan nilai 3,45%. Ekstrak metanol memiliki aktivitas antibakteri tertinggi dengan diameter zona hambat sebesar 1-14 mm. Konsentrasi hambat minimum (KHM) bakteri Escherichia coli sebesar 0,5 mg/mL, Staphylococcus aureus sebesar 0,2 mg/mL, Pseudomonas aeruginosa dan Salmonella typhimurium masing–masing sebesar 0,7 mg/mL. Komponen aktif yang terkandung dalam ekstrak metanol adalah alkaloid, tanin, saponin, fenol hidrokuinon, flavonoid, dan triterpenoid. Bioautografi aktivitas antibakteri terhadap bakteri uji E. coli menghasilkan fraksi aktif pada nilai Rƒ 0,64 dan 0,39 sedangkan pada S. aureus nilai Rƒ sebesar 0,64 dan 0,41. Hasil identifikasi dengan pereaksi Dragendorff menunjukkan senyawa tersebut merupakan golongan senyawa alkaloid.
Keyword: antibakteri, antidiare, buah bakau (R. stylosa)

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