Judul: Protein Fraction of Rennet Extracted from Abomasum of Local Sheep by Gel Filtration Column Chromatography Method.
Abstrak: Pemisahan protein rennet yang diekstraksi dari abomasum domba lokal dilakukan dengan metode kromatografi kolom gel filtrasi untuk memisahkan enzim pepsin dan khimosin. Pada penelitian ini digunakan dua sampel abomasum domba lokal usia dewasa muda (5-12 bulan). Mukosa fundus dari kedua sampel abomasum diekstraksi menjadi rennet dan disimpan beku. Rennet ekstrak kasar kemudian diproses lebih lanjut untuk memisahkan kedua enzim melalui dua tahapan fraksinasi awal, yaitu presipitasi garam dengan amonium sulfat dan dialisa menggunakan kantong dialisa cut off 12 kD. Hasil dialisa rennet kemudian difraksinasi lebih lanjut menggunakan kromatografi kolom gel filtrasi dengan matriks berupa sephadex-G75. Rennet ekstrak kasar, hasil dialisa rennet, dan fraksi-fraksi hasil kromatografi dianalisa menggunakan uji aktivitas koagulasi susu dan SDS-PAGE untuk mengetahui keberadaan enzim pepsin dan khimosin. Fraksi-fraksi hasil kromatografi juga dianalisa menggunakan spektrofotometer 280 nm. Hasil dari penelitian ini menunjukkan bahwa pepsin dan khimosin terelusi pada fraksi-fraksi dimana total proteinnya tinggi. Fraksi-fraksi yang diperoleh dari penelitian ini dapat digunakan untuk purifikasi lebih lanjut enzim pepsin dan khimosin menggunakan metode purifikasi lain.
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Judul: Pemisahan Protein Dari Ekstrak Rennet Abomasum Domba Lokal Dengan Metode Liquid Isoelectric Focusing
Abstrak: Extract of abomasum fundic mucosae of lamb contains at least two kinds of protein including protease enzymes especially pepsin and chymosin. The purpose of this study was to fractinate protein from crude rennet extracted from fundic mucosae using liquid isoelectric focusing (IEF) and to analyze the fractinated protein in order to determine the existence of proteases enzymes based on its molecular weight. This study used each of two rennet samples represented under and above one year of age, were fractinated using IEF procedure followed by biologic examination using milk clotting activities and protein analysis using sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). IEF separate proteins by its isoelectric point (pI). The results of fractination showed that chymosin was examined around pH 4.5- 5.0. Milk clotting activities showed that fractinated rennet provide less time to coagulate than crude rennet samples. It showed that the fractinated rennet resulting milk curd formation better than the crude rennet. The protein analysis of the fractinated samples contained bands of protein, and one was considered as chymosin related to its molecular weight (31 kDa). The conclusion is liquid isoelectric focusing method could possibly fractinate crude rennet samples. Further research is necessary to optimize the purification method.
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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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