Judul: Pengaruh Perebusan terhadap Kandungan Gizi Kerang Pokea (Batissa violacea celebensis Martens 1897) dan Aktivitas Antioksidannya
Abstrak: Pokea mussel is a bivalves Family Corbiculidae from the Pohara River Southeast Sulawesi. Pokea mussel are usually boiled before consumption, and believed to be able to cure various diseases such as jaundice, malaria, asthma, lower blood pressure, and fever. This study aimed to determine the effect of boiling on nutrient content of pokea mussel and their antioxidant activity. Nutrient content were determined in raw and boiled pokea mussel, while the antioxidant activity determined by DPPH method. Relativelly in general boiling did not significantly decrease nutrient contents of pokea mussel, but it did decrease the lipid content of pokea mussel as far as 6.09%; carbohydrate 16.37%; potassium 51.48%, total amino acids especially lysine 38.36%; glycine 48.87%; cysteine 75.15%; serine 26.47%; free amino acids especially lysine 44.87%; valine 90.79%; threonine 92.96%; leucine 83.64%; isoleucine 89.80%; histidine 89.80%; methionine 50%; alanine 83.45%; proline 98.13%; glutamic acid 83.33%; glycine 88.61%; aspartic acid 86%; and taurine 56.92%. Althought the antioxidant activity in crude extract of pokea mussel are still below BHT standard, but the results of toxicity test shows that crude extract of pokea mussel has potential as a cytotoxic compound.
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Judul: Antioxidant Activity of DPPH from Seaweed Using Meta-analysis Study
Abstrak: Rumput laut merupakan salah satu komoditas hasil laut unggulan yang bernilai strategis dan dimanfaatkan sebagai sumber pangan fungsional yang memiliki aktivitas biologis seperti antioksidan. Antioksidan merupakan senyawa yang mampu menangkal radikal bebas yang kekurangan elektron pada orbital terluarnya. Berdasarkan sumbernya, antioksidan dapat diperoleh dari dalam tubuh (endogenous) maupun luar tubuh (eksogenous). Rumput laut merupakan salah satu sumber antioksidan eksogenous. Antioksidan alami semakin diminati karena dinilai memiliki tingkat keamanan yang lebih baik dibandingkan dengan antioksidan sintetik. Aktivitas antioksidan dari ekstrak rumput laut dengan metode pengujian DPPH pada beberapa tahun terakhir telah dilaporkan namun didapatkan hasil yang berbeda-beda. Oleh karena itu, diperlukan teknik analisis dan penarikan kesimpulan data dari berbagai literatur yaitu dengan meta-analisis. Penelitian ini bertujuan menentukan kesimpulan dengan meta-analisis mengenai aktivitas antioksidan tertinggi pada ekstrak rumput laut berdasarkan jenis rumput laut, habitat, metode ekstraksi dan jenis pelarut. Penelitian ini dilakukan melalui beberapa tahap, yaitu perumusan pertanyaan penelitian, penentuan kriteria inklusi dan eksklusi, pencarian dan penyeleksian artikel, ekstraksi data, pengolahan data dan interpretasi hasil meta analisis. Berdasarkan hasil pencarian dan seleksi tersebut diperoleh sebanyak 38 data dari 14 artikel yang terpilih. Analisis data dilakukan secara kuantitatif menggunakan software OpenMEE. Masing-masing data dari artikel yang terkumpul diolah menggunakan metode Hedges’d untuk diperoleh nilai overall effect size dengan nilai selang kepercayaan 95%. Pada penelitian ini juga dilakukan pengujian heterogenitas, analisis subgroup dan analisis bias publikasi. Hasil overall effect size (SMD) diperoleh sebesar -10,563 yang menunjukkan nilai bahwa aktivitas antioksidan asam askorbat lebih tinggi secara signifikan dibandingkan ekstrak rumput laut. Nilai heterogenitas yang dihasilkan sebesar 89,89% termasuk kategori tinggi sehingga perlu dilakukan analisis subgroup. Analisis subgroup dilakukan untuk melihat variabel/faktor lain yang diduga mempengaruhi hasil meta-analisis, yaitu jenis rumput laut, habitat, metode ekstraksi dan jenis pelarut yang digunakan dalam analisis antioksidan ekstrak rumput laut. Hasil analisis subgroup menunjukkan bahwa aktivitas antioksidan ekstrak rumput laut terbaik terdapat pada jenis rumput laut merah, habitat di India, metode ekstraksi soxhlet dan jenis pelarut etanol 95%. Hasil analisis bias publikasi pada metode Rosenthal diperoleh nilai Nft lebih besar dibandingkan nilai 5N + 10 yaitu sebesar 4.493, sehingga dapat dinyatakan bahwa model meta-analisis yang digunakan ini kuat karena kemungkinan bias publikasinya kecil., Seaweed is one of the superior marine product commodities with strategic value and is used as a functional food source which has biological activities such as antioxidants. Antioxidants are compounds that are able to ward off free radicals that lack electrons in their outer orbitals. Based on the source, antioxidants can be obtained from inside the body (endogenous) or outside the body (exogenous). Seaweed is a source of exogenous antioxidants. Natural antioxidants are increasingly in demand because they are considered to have a better level of safety compared to synthetic antioxidants. The antioxidant activity of seaweed extracts using the DPPH testing method has been reported in recent years but the results have been mixed. Therefore, techniques for analyzing and drawing conclusions from various literature are needed, namely meta-analysis. This research aims to determine conclusions by meta-analysis regarding the highest antioxidant activity in seaweed extracts based on seaweed type, habitat, extraction method and solvent type. This research was carried out
Keyword: DPPH, Meta-analysis, OpenMEE, Seaweed

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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