Judul: Antibacterial Activity of Meranti Bark Ethanol Extract Againts Staphylococcus aureus
Abstrak: Ekstrak kulit kayu meranti diketahui memiliki aktivitas antibakteri. Dalam penelitian ini, berbagai konsentrasi etanol, 50% (E50), 75% (E75), dan 100% (E100) digunakan sebagai pelarut untuk mengekstraksi kulit kayu menggunakan metode ekstraksi soxhlet. Hasil ekstrak ditentukan dan kemudian dilakukan uji aktivitas antibakteri terhadap S. aureus menggunakan metode difusi cakram. Kandungan fitokimia ditentukan secara kualitatif mengacu pada metode Harborne. Komposisi kimia ekstrak dengan aktivitas antibakteri tertinggi dianalisis dengan LC-MS dan dikonfirmasi dengan spektroskopi FTIR. Hasil penelitian menunjukkan bahwa rendemen ekstrak tertinggi diperoleh pada E75 (8,39%), diikuti oleh E50 (7,86%), dan E100 (6,58%). Ekstrak tersebut dapat menghambat pertumbuhan S. aureus pada kisaran sedang sampai kuat. Analisis fitokimia dan spektrum FTIR mengkonfirmasi adanya kandungan flavonoid, fenolhidrokuinon, tanin, saponin, dan triterpenoid dalam ekstrak. Analisis LC-MS menunjukkan adanya (+)-Nootkatone, aurantimide acetate, Vitisin C, Kievitone yang diduga berperan dalam aktivitas antibakteri terhadap S. aureus., Meranti bark extract has been known posses the antibacterial activity. In this study, various concentrations of ethanol, 50% (E50), 75% (E75), and 100% (E100) was used as solvent to extract the bark using soxhlet extraction method. The extract yields were determined and then subjected to the antibacterial activity assay against S. aureus using disc diffusion method. The phytochemicals content was determined qualitatively reffered to Harborne method. The chemical composition of the extract with the highest antibacterial activity was analyzed by LC-MS and confirmed by FTIR spectroscopy. The study showed that the highest extract yield was obtained in E75 (8.39%), followed by E50 (7.86%), and E100 (6.58%). The extract can inhibited the growth of S. aureus in the range of moderate to strong. The phytochemical analysis and FTIR spectrum confirmed flavonoid, phenolhydroquinone, tannin, saponin, and triterpenoid in the extract. LC-MS analysis showed the presence of (+)-Nootkatone, aurantimide acetate, Vitisin C, Kievitone that suggested have a role in the antibacterial activity against S. aureus
Keyword: antibakteri, konsentrasi pelarut, etanol, meranti, rendemen, sokhlet, antibacterial, ethanol solvent concentration, meranti, soxhlet, yield

Judul: Aktivitas Antibakteri Zat Ekstraktif Kayu Bidara Laut (Strychnos lingustrina Blume).
Abstrak: Sumberdaya hutan di Indonesia tersedia cukup tinggi dengan berbagai jenis tumbuhan yang berguna untuk meningkatkan kesejahteraan manusia. Kayu bidara laut (Strychnos ligustrina Blume) merupakan tanaman yang banyak digunakan untuk mengobati berbagai penyakit. Penyakit infeksi masih merupakan penyebab utama tingginya angka kesakitan (morbidity) dan angka kematian (mortality) di negara berkembang. Pengobatan kurang efektif akibat bakteri penyebab infeksi yang resisten. Penelitian ini bertujuan untuk menentukan kadar ektraktif dan aktivitas antibakteri ekstrak kayu bidara laut hasil meserasi pelarut etanol pada konsentrasi yang berbeda terhadap bakteri S. thypi, S. dysenteriae, S. aureus, dan S. epidermidis. Pelarut yang digunakan dalam proses ekstraksi ini adalah pelarut etanol dengan berbagai konsentrasi, yaitu 0%, 25%, 50%, 75%, dan 100%. Hasil ekstraksi dengan metode meserasi menunjukan bahwa rendemen kayu bidara laut dengan terlarut etanol pada konsentrasi 0%, 25%, 50%, 75%, dan 100% secara berturut turut sebesar 3,51%, 3,71%, 5,47%, 5,03%, dan 3,93%. Zat ekstraktif kayu bidara laut terlarut etanol 50% dan 75% penelitian ini tergolong tinggi, sedangkan zat ekstraktif pada pelarut etanol konsentrasi 0%, 25%, dan 100% tergolong sedang. Aktivitas antibakteri ekstrak etanol 50% pada konsentrasi ekstrak 60% terhadap S. aureus masuk dalam kategori kuat, ekstrak etanol 25% dan 75% terhadap S. aureus masuk dalam kategori rendah-sedang dan tidak ada aktivitas antibakteri esktrak etanol 0%dan 100% terhadap S. aureus pada konsentrasi ekstrak 10-60%. Aktivitas antibakteri ekstrak etanol 0%, 25%, 50%, 75%, dan 100% terhadap bakteri S. epidermidis masuk dalam kategori rendah-sedang pada konsentrasi 20-60%. Aktivitas antibakteri ekstrak etanol 25% dan 75% terhadap bakteri S. dysenteriae masuk dalam kategori sedang dan tidak ada aktivitas antibakteri ekstrak etanol 0%, 75%, dan 100% terhadap S. dysenteriae pada konsentrasi ekstrak 10-60%. Tidak ada aktivitas antibakteri ekstrak etanol 0-100% terhadap bakteri S. thypi dari konsentrasi ekstrak 10-60%.
Keyword: Strychnos ligustrina, antibakteri, Staphylococcus aureus, Staphylococcus epidermidis, Salmonella. thypi, Shigella dysenteriae

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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