Judul: Penapisan Fitokimia dan Uji Aktivitas Antibakteri Ekstrak Biji Salak Suwaru (Salacca zalacca) terhadap Streptococcus pneumoniae
Abstrak: Pemanfaatan salak yang ada saat ini paling banyak adalah pada bagian daging buahnya saja, sedangkan pemanfaatan biji nya masih kurang mendapat perhatian. Beberapa penelitian telah membuktikan adanya aktivitas farmakologi pada biji buah salak. Penelitian ini bertujuan menentukan aktivitas antibakteri dari ekstrak bertingkat biji buah salak suwaru (Salacca zalacca) terhadap bakteri Streptococcus pneumoniae. Proses ekstraksi simplisia biji salak dilakukan dengan menggunakan teknik maserasi bertingkat dengan beberapa pelarut diantaranya n-heksana, etil asetat, dan etanol 96%. Penapisan pertama menggunakan metode difusi cakram dengan konsentrasi 200 mg/mL, kemudian pengukuran konsentrasi hambat minimum (KHM) dan konsentrasi bunuh minimum (KBM) menggunakan metode mikrodilusi dan subkultur pada media agar. Hasil uji difusi cakram menunjukkan bahwa hanya ekstrak n-heksana dan etil asetat yang mempunyai aktivitas antibakteri. Nilai KHM ekstrak n-heksana dan etil asetat adalah 0.31 mg/mL dan 1.25 mg/mL, sedangkan nilai KBM ekstrak n-heksana dan etil asetat adalah 0.63 mg/mL dan 1.25 mg/mL. Hasil tersebut menunjukkan bahwa ekstrak n-heksana memiliki aktivitas antibakteri yang cukup kuat terhadap Streptococcus pneumoniae.
Keyword: antibakteri, biji salak, KHM, KBM, Streptococcus pneumoniae

Judul: Kandungan Nutrisi dan Daya Inhibisi α-glukosidase Ekstrak Daging Buah Salak Sidempuan (Salacca sumatrana).
Abstrak: Penelitian terhadap pemanfaatan salak khususnya salak Sidempuan sebagai inhibitor α-glukosidase belum dilakukan. Penelitian ini bertujuan mengukur kadar proksimat (air, abu, protein kasar, lemak kasar, serat kasar, dan karbohidrat), menganalisis komponen fitokimia, kandungan total fenolik dan aktivitas penghambatan α-glukosidase pada ekstrak air dan etanol daging buah salak Sidempuan. Kadar total fenol diukur menggunakan metode Folin Ciocalteu. Aktivitas penghambatan α-glukosidase diukur menggunakan substrat pNPG. Kadar karbohidrat, air, abu, lemak kasar, protein kasar, dan serat kasar berturut-turut sebesar 86.35%, 6.57%, 3.60%, 1.44%, 1.24%, dan 0.82%. Kedua ekstrak mengandung senyawa flavonoid dan saponin. Ekstrak etanol 70% daging buah salak Sidempuan memiliki kandungan total fenol sebesar 10.6 mg GAE/g ekstrak, lebih tinggi dibandingkan ekstrak air sebesar 5.55 mg GAE/g esktrak. Ekstrak etanol daging buah salak Sidempuan memiliki konsentrasi inhibisi (IC50) sebesar 13.69 mg/L. Konsentrasi ini lebih kecil dibandingkan ekstrak air yaitu 4160.56 mg/L, namun masih lebih besar dibandingkan akarbosa yaitu 1.15x10-3 mg/L sebagai kontrol positif.
Keyword: α-glukosidase, total fenol, salak Sidempuan

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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