Judul: Uji aktivitas antioksidan dari keong matah merah (Cerithidea obtusa)
Abstrak: Tingginya tuntutan jaman terhadap aktivitas dunia kerja cenderung memaksa masyarakat untuk berpindah ke hal-hal yang bersifat cepat dan instan termasuk dalam hal pola makan. Pola makan yang tidak tepat akan menyebabkan akumulasi jangka panjang terhadap radikal bebas di dalam tubuh. Antioksidan bertindak melalui mekanisme pemutusan rantai radikal bebas, detoksifikasi serta mengaktifkan enzim-enzim antioksidan (superoksid dismutase, katalase, glutation peroksidase) termasuk kadar glutation reduksi (GSH). Salah satu alternatif sumber antioksidan adalah keong matah merah. Penelitian ini bertujuan untuk mengetahui aktivitas antioksidan dari keong matah merah (Cerithidea obtusa), keong yang digunakan berasal dari pasar Muara Angke Jakarta. Habitat keong matah merah adalah pantai dengan substrat berlumpur. Keong didapatkan dalam keadaan hidup. Sampel keong dibawa dengan menggunakan sterofoam. Setelah sampel sampai, tutup sterofoam dibuka agar keong tetap mendapatkan oksigen yang cukup. Substrat lumpur yang ada digunakan untuk mempertahankan suhu lingkungan dan sumber mendapatkan makanan untuk keong tersebut. Penelitian dibagi dalam dua tahap, yaitu penelitian pendahuluan dan penelitian utama. Penelitian pendahuluan meliputi ekstraksi komponen antioksidan tahap penapisan dan ekstraksi dengan metode bertingkat serta uji aktivitas antoksidan dengan metode DPPH. Penelitian utama meliputi preparasi keong dan analisis proksimat, ekstraksi bahan aktif, uji aktivitas antioksidan, uji fitokimia dan uji bilangan peroksida. Berdasarkan hasil penelitian diketahui bahwa pelarut yang paling baik digunakan dalam ekstraksi adalah metanol dengan metode ekstraksi secara tunggal. Nilai rendemen terbesar diperoleh dari ekstrak metanol yaitu sebesar 2,68 % diikuti oleh etil asetat 1,25 % dan ekstrak heksana 0,2 %. Keong matah merah memiliki kandungan kadar air 75,98 %; kadar abu 5,73 %; kadar lemak 2,55 % dan kadar protein 9,85 %. Nilai aktivitas antioksidan yang ditunjukkan dengan nilai IC50 pada pelarut metanol, heksan dan etil asetat berturut-turut yaitu 967,89 ppm ; 34.582,1 ppm; dan 2,80 x 106 ppm. Aktivitas antioksidan terbaik adalah ekstraksi dengan menggunakan pelarut metanol yaitu 967,89 ppm. Berdasarkan hasil aplikasi ekstrak metanol terhadap emulsi minyak maka dapat dilihat bahwa kemampuan ekstrak keong matah merah sebagai antioksidan berpengaruh nyata terhadap penghambatan aktivitas oksidasi lemak. Nilai bilangan peroksida pada emulsi minyak dengan penambahan ekstrak 0 ppm; 2000 ppm; 3000 ppm; dan 4000 ppm berturut-turut 4,75 Meq O2/1000g; 3,92 Meq O2/1000g; 3,33 Meq O2/1000g dan 2,83 Meq O2/1000g. Uji fitokimia terhadap ekstrak keong matah merah (Cerithidea obtusa) terpilih yang mempunyai aktivitas antioksidan, menunjukkan bahwa keong matah merah mengandung senyawa bioaktif golongan alkaloid dan flavonoid.
Keyword: 

Judul: Kajian Aktivitas Komponen Bioaktif dari Keong Matah Merah (Cerithidea obtusa)
Abstrak: Cerithidea obtusa is one of species that can be found in the mangrove ecosystem in the Asia-Pacific region. It has been widely used for food and reliable as medicine. This study was aimed to explore the potential of bioactive components activity through characterization of C. obtusa; characterization of C. obtusa extract; antioxidant, antidiabetic, antiinflammatory and antibacterial activity assay of C. obtusa extract in vitro. The characterization of C. obtiusa were included identification, morphometric observations, proportions and proximate analysis. Whereas, the characterization of C. obtusa extract were included yield, extract descriptions, toxicity with BSLT method, and screening of active component qualitatively. Bioactive activity was measured in vitro included antioxidant by DPPH method, antidiabetic by α-glucosidase inhibition method, antiinflammatory by red blood cell membrane stabilizing method, and antibacterial by disc diffusion method. The identification results indicated that the C. obtusa had a blunt at the tip of the shell characterization. The average of shell length, shell width, columella width, and weight were 40.5 mm, 19.9 mm, 16.9 mm, and 5.1 g, respectively. The proportion of shells, meat, and offal were 66.7%, 18.1%, and 15.2%, respectively. Moisture content, protein, fat, ash, and carbohydrate were 82.8%, 11.9%, 0.3%, 2.0%, and 3.1%, respectively. The highest yield was methanol extract (4.7%), followed by ethyl acetate extract (0.5%) and n-hexane extract (0.2%). All of extracts had characteristics of paste form and fishy smell. The colour of methanol extract, ethyl acetate extract, and n-hexane extract were faded green, dark green, and tawny, recpectively. Toxicity test showed that all of extracts were toxic with the lowest of LC50 value was n-hexan extract (176.3 μg/ml), followed by ethyl acetate extract (476.3 μg/ml) and methanol extract (715.4 μg/ml). Screening of active component adduced that methanol extract contained alkaloids, flavonoids, triterpenoids, and saponins; ethyl acetate extract contained flavonoids, phenolic hydroquinone, triterpenoids, and saponins; n-hexane extract contained triterpenoids. Ethyl acetate extract had antioxidant activity (IC50 = 645,6 μg/ml) while methanol extract had antidiabetic activity (IC50 = 36.4 mg/ml). antiinflammatory activity was not found at all of extracts while antibacteria activity was discovered at n-hexane extract but the activity was very low (MIC = 46 mg/ml).
Keyword: Antibacteria, antidiabetes, antiinflammatory, antioxidant, Cerithidea obtusa

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