Judul: Korelasi Gugus Fungsi dan Aktivitas Antioksidan Daun Salam (Syzygium polyanthum) Menggunakan Metabolomik Berbasis Spektrum Inframerah
Abstrak: Daun salam (Syzygium polyanthum.) memiliki banyak khasiat, salah satunya adalah karena kandunga antioksidan. Penelitian ini bertujuan menentukan korelasi antara aktivitas antioksidan dan spektrum inframerah (FTIR) ekstrak daun menggunakan metabolomik. Aktivitas antioksidan ekstrak daun dengan ragam konsentrasi pelarut menunjukkan nilai aktivitas antioksidan tertinggi pada ekstrak etanol 70%, sementara kadar fenolik total tertinggi pada ekstrak etanol 50%. Profil spektrum FTIR ekstrak dengan berbagai konsentrasi menunjukkan sampel memiliki pola spektrum yang mirip. Ekstrak daun dapat dikelompokkan berdasarkan ragam pelarut pengekstraksi menggunakan principal component analysis (PCA) dengan total PC 88%. Data absorbans gugus fungsi dan nilai IC50 dari ekstrak telah dianalisis untuk mencari korelasinya menggunakan partial least square (PLS). Hasil analisis PLS menunjukkan bilangan gelombang 1600 cm-1 dari gugus fungsi C=C diduga merupakan gugus yang berkontribusi paling tinggi pada aktivitas antioksidan ekstrak daun.
Keyword: antioksidan, fenolik total, FTIR, PCA, pelarut pengekstraksi, PLS

Judul: Pengaruh Umur Daun dan Jenis Pelarut terhadap Aktivitas Antioksidan Ekstrak Daun Salam (Syzigium polyanthum).
Abstrak: Syzygium polyanthum yang dikenal dengan nama tanaman salam atau daun salam sering dimanfaatkan sebagai bumbu masakan. Tanaman ini juga digunakan sebagai obat tradisional untuk mengatasi hipertensi, hiperurisemia, dan diabetes. Beberapa penelitian melaporkan bahwa tanaman ini memiliki senyawa bioaktif yang dapat berperan sebagai antioksidan. Tujuan penelitian ini adalah mengetahui pengaruh umur daun dan jenis pelarut dalam proses ekstraksi terhadap aktivitas antioksidan. Uji kadar total fenol dan asam kafeat dilakukan sebagai penunjang hasil uji aktivitas antioksidan. Pada penelitian ini, daun muda adalah daun yang berada di pucuk sedangkan daun tua berada di pangkal ranting. Proses ekstraksi dilakukan dengan metode sonikasi menggunakan pelarut metanol dan air. Aktivitas antioksidan ekstrak daun salam berkisar antara 28.82-63.93 μg/mL ekstrak. Kadar total fenol berkisar antara 116.98-304.48 μg GAE/mg ekstrak. Kadar asam kafeat berkisar antara 38.78-103.47 μg asam kafeat/mg ekstrak. Hasil uji statistika menunjukkan variabel umur daun dan jenis pelarut memiliki pengaruh yang signifikan terhadap aktivitas antioksidan dan kadar total fenol namun tidak signifikan terhadap kadar asam kafeat ekstrak daun salam. Daun tua memiliki aktivitas antioksidan dan kadar total fenol yang lebih tinggi dibandingkan daun muda. Ekstrak metanol memiliki aktivitas antioksidan dan kadar total fenol yang lebih tinggi dibandingkan dengan ekstrak air.
Keyword: antioksidan, asam kafeat, daun salam, senyawa fenolik, antioksidan, asam kafeat, daun salam, senyawa fenolik

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: