Judul: Potensi Ekstrak Etanol Biji Kurma (Phoenix dactylifera L.) Sebagai Antidiabetes Dengan Parameter Kinetika Inhibisi α-Glukosidase
Abstrak: Biji kurma merupakan salah satu hasil samping dari industri sari kurma yang berpotensi untuk diolah lebih lanjut. Biji kurma mengandung senyawa aktif yang diketahui memiliki kemampuan untuk menghambat α-glukosidase. Penelitian ini bertujuan mengukur aktivitas ekstrak etanol 70% dan fraksi biji kurma dengan mekanisme dalam menginhibisi α-glukosidase. Pengukuran aktivitas inhibisi dilakukan dengan mengekstraksi biji kurma menggunakan pelarut air dan etanol 70%. Hasil ekstraksi kemudian difraksinasi dengan pelarut n-heksana, etil asetat, n-butanol, dan air. Selanjutnya dilakukan perhitungan total fenolik dan flavonoid masing-masing ekstrak dan fraksi. Pengukuran aktivitas inhibisi α-glukosidase diukur berdasarkan reaksi substrat terhadap enzim dengan penambahan inhibitor. Hasil penelitian menunjukkan bahwa ekstrak etanol memiliki total fenolik dan flavonoid tertinggi, yaitu masing-masing sebesar 76.86 mg GAE/g dan 21.19 mg QE/g. Fraksi n-heksana memiliki aktivitas inhibisi yang paling baik dilihat dari nilai IC50, yaitu sebesar 12.69 mg/L. Kinetika inhibisi ekstrak etanol 70% biji kurma adalah inhibisi campuran (mixed inhibition).
Keyword: α-glukosidase, biji kurma, fenolik, flavonoid, kinetika inhibisi

Judul: Aktivitas Inhibisi Enzim α-Glukosidase dari Ekstrak Etanol 70 % dan Fraksi Ekstrak Daun Kembang Bulan (Tithonia diversifolia).
Abstrak: α-Glukosidase merupakan enzim yang menjadi target penghambatan untuk menjaga kadar gula darah pada penderita diabetes mellitus. Penelitian terdahulu menunjukkan ekstrak etanol daun kembang bulan (Tithonia diversifolia) mampu menghambat α-glukosidase namun belum adanya penelitian terkait aktivitas dari fraksi ekstrak daun kembang bulan terhadap penghambatan α-glukosidase. Penelitian ini bertujuan menentukan kandungan total fenolik, kandungan total flavonoid, dan nilai IC50 terhadap penghambatan α-glukosidase oleh ekstrak etanol 70 % daun kembang bulan beserta fraksinya. Daun kembang bulan diekstraksi dengan pelarut etanol 70 % kemudian dilakukan fraksinasi menggunakan pelarut n-heksana, etil asetat, n-butanol, dan air. Senyawa hasil fraksinasi dipekatkan dengan rotary evaporator dan dilakukan uji total flavonoid, total fenolik, serta aktivitas inhibisi enzim α-glukosidase berdasarkan pengukuran nilai IC50 masing-masing ekstrak dan fraksi ekstrak daun kembang bulan. Proses ekstraksi menghasilkan rendemen ekstraksi sebesar 12.89 % dari pelarut etanol 70 %. Fraksi air merupakan fraksi dengan kandungan fenolik tertinggi sedangkan fraksi etil asetat merupakan fraksi dengan kandungan flavonoid tertinggi. Fraksi etil asetat sebagai fraksi terbaik dengan nilai IC50 sebesar 3.09 mg/mL dan kandungan total flavonoid tertinggi.
Keyword: α-glukosidase, fenolik, flavonoid, IC50, Tithonia diversifolia

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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