Judul: Potensi ekstrak daun jambu biji merah (psidium guajava) dan daun sirsak (annona muricata) untuk menghambat proliferasi sel kanker raji
Abstrak: Daun jambu biji merah (Psidium guajava) mengandung senyawa kuersetin dan daun sirsak (Annona muricata) mengandung kaempferol. Kedua senyawa flavonoid tersebut memiliki potensi menghambat proliferasi sel kanker. Tujuan penelitian ini adalah mengevaluasi potensi fraksi ekstrak daun jambu biji merah (fraksi kaya-kuersetin) dan fraksi ekstrak daun sirsak (fraksi kaya-kaempferol) dalam menghambat proliferasi sel kanker Raji dengan metode ekstraksi maserasi. Ekstrak metanol didapatkan dengan memaserasi serbuk sampel setelah sampel dibebaskan dari senyawa nonpolar menggunakan n-heksana. Ekstrak dari setiap sampel dimurnikan menggunakan kromatografi cair vakum dan didapatkan 0.28% fraksi kaya-kuersetin, dan 2.00% fraksi kaya-kaempferol. Kadar aglikon kuersetin dan kaempferol berdasarkan kromatografi cair kinerja tinggi berturut-turut 1.27 dan 0.67 ppm. Kedua fraksi diuji efek penghambatannya terhadap sel Vero (sel normal) dan sel Raji (se kanker darah). Persen penghambatan kedua fraksi terhadap sel Vero sebesar 200 ppm. Hasil pada sel Raji menunjukkan rendahnya persen penghambtan kedua ekstrak, terutama fraksi kaya-kuersetin tidak menunjukkan penghambatan sel. Berdasarkan hasil tersebut disimpulkan bahwa fraksi kaya-kuersetin dan kaempferol tidak berpotensi dalam menghambat proliferasi sel kanker Raji. Kata kunci: antikanker, jambu biji merah, kaempferol, kuersetin, sirsak
Keyword: nticancer, guava, kaempferol, quercetin, soursop

Judul: Kuersetin dari Ekstrak Daun Jambu Biji Merah (Psidium guajava) dan Kinerjanya sebagai Penghambat Proliferasi Sel Kanker
Abstrak: Red guava leaf (Psidium guajava) extract has been known to inhibit cancer cell proliferation. However, further studies on the activity of flavonoids in red guava leaves as an anticancer agent has not been done. This study aims to test the inhibitory activity on Raji cells (ATCC CCL-86) by quercetin in guava leaves. Methanol crude extract was fractionated using vacuum liquid chromatography and column chromatography techniques to obtain fraction rich of quercetin. Fractionation of the crude methanol extract gave a fraction which shows a spot at Rf 0.675, which is similar to that of standard quercetin. Identification of quercetin fraction with liquid chromatography-mass spectrometry showed the fragment ion spectra of the quercetin (m/z 150, 151, 152). The quercetin fraction has been tested for its activity toward Raji cells and Vero cells. The quercetin fraction inhibited proliferation of Raji cells by 60%, at a concentration of 100 mg mL-1, but only inhibits the proliferation of Vero cells by 10%. This result indicates the quercetin fraction of guava leaf is able to inhibit the proliferation of Raji cells, but not toward Vero cells.
Keyword: quercetin, Psidium guajava, flavonoids, cancer cells proliferation

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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