Judul: Kandungan Total Fenolik, Flavonoid, dan Aktivitas Antioksidan Ekstrak Biji Jengger Ayam (Celosia cristata) pada Berbagai Pelarut.
Abstrak: Molekul yang memiliki satu atom atau lebih elektron yang tidak berpasangan dapat disebut radikal bebas. Tubuh dapat mengalami stress oksidatif karena keterbatasan antioksidan, yaitu keadaan ketika kemampuan tubuh dalam menangkal radikal bebas lebih kecil daripada jumlah radikal bebas di dalam tubuh. Salah satu tanaman yang diketahui memiliki potensi antioksidan adalah biji tanaman jengger ayam. Penelitian ini bertujuan untuk menentukan kandungan total fenolik, flavonoid, dan aktivitas antioksidan ekstrak pelarut berbeda dari biji jengger ayam. Pelarut yang digunakan antara lain akuades, metanol, etanol, aseton, dan isopropanol. Rentang total fenolik sebesar 0.212 ± 0.022 - 2.192 ± 0.023 mg GAE/g bobot kering, flavonoid sebesar 0.083 ± 0.006 - 0.272± 0.015 mg QE/g bobot kering, dan aktivitas antioksidan metode DPPH sebesar 0.349 ± 0.01 - 1.069 ± 0.052 μmol TE/g bobot kering. Rentang aktivitas antioksidan metode FRAP dan CUPRAC sebesar 3.152 ± 0.112 - 6.666 ± 0.089 μmol TE/g bobot kering dan 0.776 ± 0.03 – 32.492 ± 01.62 μmol TE/g bobot kering. Berdasarkan uji fenolik dan flavonoid didapatkan pelarut terbaik adalah akuades. Berdasarkan uji aktivitas antioksidan DPPH terbaik pada pelarut akuades sedangkan metode FRAP dan CUPRAC adalah pelarut aseton.
Keyword: CUPRAC, DPPH, fenolik, flavonoid, FRAP

Judul: Kandungan Total Saponin dan Aktivitas Antibakteri Ekstrak Bunga dan Biji Jengger Ayam (Celosia cristata L.)
Abstrak: Tanaman jengger ayam (Celosia cristata L.) merupakan tumbuhan yang dapat dijadikan alternatif sebagai antibakteri. Tanaman jengger ayam memiliki kandungan metabolit sekunder yaitu saponin yang dapat berfungsi sebagai antibakteri. Tujuan dari penelitian ini adalah menentukan kadar total saponin menggunakan metode vanilin-asam sulfat dan aktivitas antibakteri ekstrak air, metanol dan etanol terhadap bakteri Staphylococcus aureus dan Escherichia coli menggunakan metode difusi cakram dari bunga dan biji tanaman jengger ayam. Kadar total saponin tertinggi yaitu pada ekstrak air sebesar 4,4873 mg DE/ g ekstrak pada bunga dan sebesar 3,1107 mg DE/ g ekstrak pada biji. Aktivitas antibakteri bunga dan biji jengger ayam diuji terhadap bakteri Escherichia coli dan Stapylococcus aureus. Ekstrak metanol pada sampel bunga dengan konsentrasi 1000 ppm memiliki aktivitas antibakteri tertinggi sebesar 4,71 mm terhadap E.coli yang tergolong sedang dan sebesar 2,60 mm terhadap S.aureus yang tergolong lemah. Aktivitas antibakteri pada biji tanaman jengger ayam tergolong lemah yaitu pada ekstrak etanol sebesar 3,69 mm terhadap E.coli dan pada ekstrak air sebesar 2,54 mm terhadap S.aureus. Bunga dan biji tanaman jengger ayam memiliki daya hambat yang paling baik terhadap E.coli dibandingkan S.aureus.
Keyword: Antibacterial, cockscomb, saponin, water

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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