Judul: Aktivitas antibakteri zat ekstraktif kulit kayu rambai (Baccaurea motleyana Muell. Arg.)
Abstrak: Rambai (Baccaurea motleyana Muell.Arg.) belongs to the family Euphorbiaceae have potency for developed as antibacterial. The aims of this research were to determine the antibacterial activity and to screen phytochemically constituents of bark extract of B. motleyana. Bark of B. motleyana used in traditional medicine for the treatment of eye diseases was extracted by maceration in ethanol and aqueous. In vitro antibacterial activity was determined using agar well diffusion method on Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa. The results showed that that 50 mg/ml of the aqueous extract was most active and it inhibited the growth of all the bacterial with zones of inhibitation ranging from 4.10 to 8.67 mm. Fractionation to aqueous extract can decreases minimum inhibitory concentration (MIC) values and increases sensitivity of bacteria to that fraction. MIC of the aqueous extract for three bacterial strains ranging from 5.40 mg/ml to 6.82mg/ml, the methanol-insoluble fraction 4.09 mg/ml to 6.72 mg/ml, n-hexaneinsoluble fraction 3.77mg/ml to 4.56 mg/ml and the subfraction (F ) 0.39 to 0.61 mg/ml. Results of phytochemical screening showed the presence of saponin and flavonoid in the aqueous extract. Identified with FTIR, LCMS and NMR's Proton showed that active compound that potentially as antibacterial is aglikon of saponin's compound.
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Judul: Aktivitas Antibakteri Ekstrak Kulit Rambutan (Nephelium lappaceum) Terhadap Staphylococcus aureus & Escherichia coli
Abstrak: Tanaman rambutan adalah salah satu jenis tanaman buah yang banyak ditanam oleh masyarakat Indonesia. Namun masyarakat hanya menggunakan daging buahnya saja, sedangkan kulit buah rambutan terbuang menjadi limbah. Penelitian ini bertujuan mengetahui konsentrasi minimum ekstrak kulit rambutan yang mampu menghambat dan membunuh pertumbuhan bakteri Gram positif ( Staphylococcus aureus) dan bakteri Gram negatif (Escherichia coli). Kulit rambutan diekstraksi menggunakan dua pelarut yaitu pelarut etanol 70% dan pelarut air. Nilai rendemen ekstrak dari pelarut etanol 70% dan air yaitu masingmasing sebesar 21.10% dan 33.54%. Hasil analisis fitokimia diketahui bahwa ekstrak etanol 70% dan ekstrak air kulit rambutan mengandung senyawa tanin, saponin, flavonoid, alkaloid, dan triterpenoid. Uji aktivitas antibakteri menunjukkan adanya daya hambat pada bakteri Gram positif (Staphylococcus aureus) tetapi tidak menghambat bakteri Gram negatif (Escherichia coli). KHTM pada bakteri S. aureus terlihat pada konsentrasi 20 mg/mL dengan diameter zona hambat yang dihasilkan oleh ekstrak etanol 70% dan ekstrak air masing-masing sebesar 7.11 mm dan 7 mm. Sedangkan KBM ekstrak etanol 70% dan ekstrak air terhadap S. aureus pada konsentrasi 60 mg/mL yang ditandai dengan tidak adanya koloni bakteri yang tumbuh pada media agar setelah kontak selama 10 menit dengan ekstrak.
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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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