Judul: Transglikosilasi enzimatik polifenol-X-glukosida dan pemanfaatannya sebagai senyawa antioksidan
Abstrak: Antioksidan telah lama dikenal manfaat dan kegunaannya dalam industri farmasi, kosmetik dan makanan. Penambahan antioksidan pada lemak maupun bahan pangan merupakan cara paling efektif untuk mencegah oksidasi lemak. Selama ini antioksidan yang umum digunakan adalah antioksidan sintetik seperti butylated hydroxy unisole (BHA) dan butylated hydroxy toluene (BHT). Namun penggunaannya semakin dikhawatirkan oleh masyarakat karena beberapa penelitian membuktikan adanya efek toksik dan karsinogenik terhadap tubuh manusia (Osawa et 1992). Sehingga akhir-akhir ini perhatian. terhadap antioksidan alami yang berasal dari tumbuh-tumbuhan semakin meningkat karena dianggap lebih baik dari antioksidan sintetik, khususnya bila ditinjau dari segi kesehatan. Antioksidan alami terdapat dalam banyak tumbuhan obat yang biasanya terdapat dalam bagian daun, buah, akar, batang, dan biji. Bagian tersebut umumnya mengandung senyawa fenol atau polifenol (Pratt, 1992). Telah lama dikenal bahwa beberapa senyawa polifenol dan turunannya memiliki aktivitas antibakteri, antioksidan, antimelanogenesis, dan antimutagen (Ahn et al., 1991; loku et al., 1992; Funayama et al., 1995). Schagai antioksidan, polifenol berperan dalam menangkap radikal bebas penyebab peroksidasi lipid yang dapat menimbulkan kerusakan pada bahan makanan. Selain itu menurut Sulistyo et al. (1998) senyawa antioksidan berfungsi mencegah kerusakan sel dan DNA akibat adanya senyawa radikal bebas.
Keyword: 

Judul: Penapisan Awal Senyawa Antioksidan Dari Ekstrak Gelidiella acerosa
Abstrak: Salah satu kerusakan bahan pangan yang sering tetjadi selama penyimpanan dan pengolahan adalah terjadinya reaksi oksidasi lemak dalam bahan pangan sehingga menyebabkan menurunnya kualitas organoleptik dan nilai gizinya. Karena itu diperlukan pcnambahan antioksidan ke dalam bahan pangan tersebut. Selain digunakan dalam produk pangan, antioksidan juga dimanfaatkan sebagai suplemen untuk mengatasi proses oksidasi di dalam tubuh. Pada keadaan normal, secara fisiologis sel memproduksi radikal bebas sebagai konsekuensi logis reaksi biokimia dalam kehidupan aerobik. Pada saat ini, lingkungan yang tercemar yang berasal dari polusi udara, polusi air, bahan-bahan kimia, obat-obatan, pestisida, dapat merangsang timbulnya radikaI bebas dalam tubuh.
Keyword: 

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.
Keyword: