Judul: Analisis in vitro Toleransi Isolat Bakteri Asam Laktat asal Daging Sapi terhadap pH Lambung, pH Usus dan Garam Empedu sebagai Kandidat Probiotik.
Abstrak: Bakteri asam laktat merupakan mikroflora normal daging sehingga lebih sesuai bila dijadikan kultur starter untuk pengolahan produk fermentasi yang berasal dari daging. Syarat utama suatu isolat berpotensi sebagai probiotik adalah memiliki toleransi yang tinggi terhadap asam lambung dan garam empedu dalam saluran pencernaan. Kondisi kritikal yang harus dihadapi bakteri probiotik dalam saluran pencernaan manusia dimulai dari lambung, yaitu bakteri harus mampu bertahan terhadap pH yang sangat rendah (pH 2,0) selama minimal 90 menit. Bakteri probiotik selanjutnya memasuki saluran usus bagian atas (pH 7,2) yang merupakan tempat disekresikan garam empedu. Penelitian ini bertujuan untuk melakukan seleksi bakteri asam laktat hasil isolasi dari daging sapi dari pasar tradisional di kabupaten Bogor (Arief et al., 2006) untuk mendapatkan kandidat isolat probiotik yang mempunyai karakteristik pertumbuhan terbaik dalam kondisi lingkungan asam kuat HCl sesuai dalam lambung dan adanya garam empedu (0,3%) sesuai usus halus.
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Judul: Analisis in vitro toleransi isolat bakteri asam laktat asal daging sapi terhadap pH lambung, pH usus dan garam empedu sebagai kandidat probiotik
Abstrak: Lactic acid bacteria have been reported to be useful as a health adjunct and are commonly added to food as delivery mechanism. As candidate for probiotic, lactic acid bacteria should have the ability to survive in the digestion process such as resistance towards gastrointestinal tract pH and bile salt concentrations. Lactic acid bacteria utilised in this research were isolated from meat. Twenty eight isolates of lactic acid bacteria selected for their resistancy towards gastric juice pH (pH 2,0) and small intestines pH (pH 7,2) with 0,3% bile salt under in vitro conditions. The result showed that all strains well grown in small intestines pH (pH 7,2), but only 10 isolates had good resistance to gastric juice pH. There were significant difference among theme (P<0,05). Bile salt 0,3% with pH 7,2 influenced significantly the growth of lactic acid bacteria selected at gastric juice condition showed that only three strains (1A5, 2B4, and 1B1) showed tolerance (P<0,05) could be used as probiotics candidate in further applications.
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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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