Judul: Aktivitas Antioksidan Rumput Laut Caulerpa Sp. Segar Dan Rebus.
Abstrak: Radikal bebas merupakan suatu molekul yang sangat reaktif dan tidak stabil, dapat mengakibatkan kerusakan protein, Deoxyribose Nucleic Acid (DNA), dan membran sel, serta dapat memicu timbulnya penyakit degeneratif. Kerusakan-kerusakan tersebut dapat dicegah dengan senyawa antioksidan alami maupun sintetik. Caulerpa sp. merupakan rumput laut hijau yang berpotensi sebagai sumber antioksidan alami. Caulerpa sp. umum diolah menjadi urap rumput laut dalam keadaan segar dan rebus. Proses perebusan dikhawatirkan dapat mengubah aktivitas antioksidannya, sehingga perlu dilakukan penelitian mengenai aktivitas antioksidan pada Caulerpa sp. segar dan rebus. Metode ekstraksi yang digunakan adalah ekstraksi tunggal menggunakan pelarut metanol selama 1×24 jam. Pengujian aktivitas antioksidan dilakukan menggunakan metode DPPH. Caulerpa sp. segar dan rebus memiliki rendemen ekstrak sebesar 8,88% dan 6,44%. Nilai IC50 Caulerpa sp. segar sebesar 452,37±8,29 ppm dan rebus sebesar 484,59±5,69 ppm. Kategori nilai IC50 ini tergolong sangat lemah berdasarkan metode 1,1-diphenyl-2-picrylhydrazyl (DPPH), sehingga perlu dilakukan uji aktivitas antioksidan dengan metode lainnya dan pemurnian ekstrak kasar Caulerpa sp..
Keyword: Antioksidan, Caulerpa sp., DPPH, ekstraksi, radikal bebas

Judul: Kandungan Senyawa Fenol rumput Laut Caulerpa racemosa dan Aktivitas Antioksidannya
Abstrak: Pola konsumsi masyarakat yang kurang tepat mengindikasikan akumulasi komponen radikal bebas dalam tubuh dengan sigatnya yang sangat reaktif. Kerusakan yang ditimbulkan radikal bebas antar lain munculnya berbagai macam penyakit degeneratif, seperti kanker, aterosklerosis, penyakit jantung koroner (PJK) dan diabetes melitus. Penangkalan kerusakan akibat radikal bebas harus dilakukan yaitu dengan antioksidan. Antioksidan yang sangat baik dikonsumsi adalah antioksidan alami, karena antioksidan sintetik dinilai toksik. Salah satu sumber antioksidan alami dari laut adalah rumput laut. Penelitian rumput laut sebagai sumber antioksidan terfokus pada negara-negara beriklim subtropis dan dingin, sementara di negara tropis masih sangat terbatas, termasuk di Indonesia. Caulerpa recemosa merupakan rumput laut khas Indonesia yang telah dimanfatkan sebagai bahan pangan oleh sebagian masyarakat pesisir
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Judul: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
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