Judul: Aktivitas antibakteri ekstrak kasar flavonoid daun gambir (Uncaria gambir Roxb)
Abstrak: Infection of diseases could be caused by Staphylococcus aureus and Eschericia coli that can be prevented by antibiotics. The use of antibiotic in high concentration causes some strains of S.aureus and E.coli become resistant. This situation will encourage the exploration of new antibacterial sources that are available in large quantities and lower resistance effect. The solution is to utilize the antibacterial potency of the leaves of gambir. The objective of this study is to examine the antibacterial activity of crude extract of flavonoids in gambir leaves. Extraction of flavonoids have been done by maceration storey method and obtained aquous extract, chloroform extract and hexane extract. The potential of those extracts have been examined to inhibit the growth of E. coli dan S. aureus by agar diffusion method. The results showed that aquous extract had antibacterial activity. Based on the phytochemical analysis, the aquous extract contained flavonoid. Bacteriostatic was determined by agar diffusion method, meanwhile the bactericidal was determined by measurement of the optical density of minimum inhibition concentration (MIC) at wavelength of 600 nm. The crude extract of flavonoids in gambir leaves are bacteriostatic against Eschericia coli and Staphylococcus aureus at concentrations of 1%, 3%, 5% and 7%. Inhibition against Eschericia coli and Staphylococcus aureus occurred at concentration of 1% and classified as weak, while the concentration of 3%, 5% and 7% was classified as strong. The crude extract flavonoid have bactericidal activity at concentration 9%.
Keyword: 

Judul: Antibacterial activities assay of aqueous fraction of gambir leaves (Uncaria gambir Roxb) by microdilution and its components analysis.
Abstrak: The potency of gambir (Uncaria gambir Roxb) leaves as a traditional medicine had known since long time ago. This is the reason for some researchers to evaluate the antibacterial activities of gambir leaves. The method that usually used for antibacterial assay is agar-diffusion which has some weakness, i.e. need more time and materials. Nowadays, microdilution become antibacterial assay method that has been developed in many countries. Microdilution gives a useful technique to determine MIC of some different samples, and require only a little number of the sample. This method also used for wide variety of microorganisms, not expensive, and gives a reproducible result. This research aimed to determine minimal inhibitory of aqueous fraction of Gambir leaves by microdilution method and identified its components by pyrolisis GC-MS. Gambir leaves extracted with methanol-water solution, and then being separated by using hexane and chloroform. Gambir leaves extraction produce three fractions, i.e. chloroform, hexane, and aqueous fraction which has yield 0.048 %, 0.031 % , and 3.033 % respectively. Fraction which is used for further analysis is aqueous fraction. The minimal inhibitory concentration of aqueous fraction of Gambir leaves toward E.coli and S.aureus growth is 0.05 mg/mL, whereas minimal bactericidal concentration was not observed within the concentration ranges of the fractions tested (0.01-40 mg/mL). Identification result by pyrolisis GC-MS showed that aqueous fraction of gambir leaves contain pyrocathecol which is composer fragment of catechin.
Keyword: 

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: