• Korean Journal of Veterinary Research
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• v.31 no.2
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• pp.155-161
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• 1991

The mechanisms of demyelination in Theiler's murine encephalomyelitis virus (TMEV)-induced chronic central nervous system(CNS) disease are still unclear and are probably multifactoral. This study was intended to culture spinal cord cells isolated from TMEV-induced demyelinating mice. By Percoll density centrifugation of enzymatically dissociated tissue, the cells were collected and then cultured on poly-L-lysine-coated plastic coverslips for 2 weeks. Oligodendrocytes, astrocytes and macrophages were identified using cell-type specific markers. Viral antigens were not present in oligodendrocytes and in astrocytes by double immunofluorescence. Affected mouse oligodendrocytes had less capacities of sheet formation and galactocerebroside immunoreactivity than those of control cell 3. These findings support the hypothesis that immune mediated mechanisms play an important role in the process of demyelination in this animal model.

• Bulletin of the Korean Chemical Society
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• v.26 no.11
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• pp.1819-1822
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• 2005

In the search for a simple preparation method of heterogeneous catalyst, the iron porphyrins were coordinated bonded to the surface of a polymeric core-shell nanosphere. The heterogeneous catalyst was characterized by FT-IR, scanning electron microscope, and UV-vis spectrophotometer. The iron porphyrin bound core-shell nanospheres was about 470 nm in diameter and their catalytic activity for cyclohexene oxidation was similar to a homogeneous iron porphyrin in a solvent composition range of 25-75% acetonitrile/water (v/v). In addition, they could be recovered by simple centrifugation and their catalytic activity was maintained more than the third cycle.

• YAKHAK HOEJI
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• v.38 no.1
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• pp.12-19
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• 1994

Capsaicin(8-methyl-N-vanillyl-6-nonenamide) is the principal pungent component of Capsicum fruits. This work is directed to the capsaicin-hydrolyzing enzyme playing a key role in the rate limiting and critical step of capsaicin metabolism. In order to get precise information on the enzyme's subcellular location, rat liver homogenate was divided into six subcellular fractions by differential centrifugation technique: crude nuclear pellet, PNS(post nuclear supernatant) fraction, lysosomal pellet, cytosol, Tris wash fraction, micrisomes. Capsaicin-hydrolysing enzyme activity was analysed by high performance liquid chromatography(HPLC). This enzyme was found at the highest specific activity in the microsomal fraction and co-distributed with marker enzymes of the endoplasmic reticulum, NADPH-cytochrome c reductase and nucleoside diphosphatase. This is compatible with the result of ninhydrin color reaction of vanillylamine, primary metabolite of capsaicin hydrolysis, on thin layer chromatography(TLC). This enzyme is most active at pH $8.0{\sim}9.0$. Definite subcellular location of this enzyme will make it easy to proceed with further study.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.4
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• pp.660-665
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• 1994

Treatment of rice-washing wastewater was considered under various pH levels and chitosan concentrations. Compared with the control test, addition of chitosan at the various concentrations did not noticeably enhanced turbidity reduction at pH 4 and 5 , but greatly enhanced at above pH 6. However, reduction of turbidity in the wastewater, irrespective of chitosan concentrations, was the greatest at pH 4 and became lower by increasing pH. Suspended solids in the wastewater were the most effectively recovered by pH adjustment of the wastewater to 4 followed by centrifugation, with over 99% reduction in turbidity . Different concentrations of suspended solids in the wastewater and various kinds of acids used for p/H adjustment did not affect turbidity reduction. Increasing storage periods of the wastewater resulted in lower reductions in turbidity.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.135.1-135
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• 2003

A technique for detection of Xanthomonas axonopodis pv. citri, a causal bacterium of canker on Unshiu orange fruits, was developed using bacteriophage. Procedure for the detection was designed on the basis of the previous reports that one group(CPI) of X. axonopodis pv. citri bacteriophage and corresponding two Iysotypes distributed in Korea. First, fruit surface was washed with sterile distilled water and pellet was obtained from centrifugation. The pellet was resuspended in Wakimoto's potato semi-synthetic broth medium and divided equally into two parts. One part was heated in boiling water to kill bacterial cells. Bacteriophages(CP$_1$) were respectively added into two parts and 0.1 ml from each part was mixed with soft agar medium. After incubation for 18 hrs at 25$^{\circ}C$, the causal bacterium of canker was determined based on plaques formed on the medium. This procedure can be effectively used for detection of living bacterial pathogen on fruit surfaces of Unshiu orange.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.6
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• pp.885-892
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• 2009

To investigate host defense mechanisms for protecting the mammary gland from mastitis infection, the membrane fraction of mammary tissues from Holstein cows was purified by differential velocity centrifugation, and then the sodium dodecyl sulfate-polyacrylamid gel electrophoresis (SDS-PAGE) separated proteins were identified by ion trap mass spectrometer equipped with a Surveyor high performance liquid chromatography (HPLC) system. A total of 183 proteins were identified. Bioinformatics software was applied to analyse physicochemical characteristics of the identified proteins and to predict biochemical function. These data may provide valuable information to investigate the mechanisms of mammary gland milk secretion and infectious disease, and enable a clear identification of proteins and potential protein targets for therapies.

• Bulletin of the Korean Chemical Society
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• v.23 no.11
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• pp.1541-1544
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• 2002

The concentration of B in steels is important due to its influence on mechanical properties of steel such as hardenability, hot workability, and creep resistance. An analytical method has been developed to determine B in steel samples by high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS). National Institute of Standard and Technology Standard Reference Material (NIST SRM) 348a was analyzed to validate the analytical method. The steel sample was digested in a centrifuge bottle with addition of aqua regia and $^{10}B$ spike isotope. Sample pH was then adjusted to higher than 10 to precipitate most matrix elements such as Fe, Cr, and Ni. After centrifugation, the supernatant solution was passed through a cation exchange column to enhance the matrix separation efficiency. B recovery efficiency was about 37%, while matrix removal efficiency was higher than 99.9% for major matrix elements. The isotope dilution method was used for quantification and the determined B concentration was in good agreement with the certified value.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11c
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• pp.600-606
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• 2000

The effect of clinostatting and microgravity on plant cells and organs is considered for two types of gravistimulation: static and dynamic. The former is eliminated by both clinostatting and microgravity; the latter is eliminated by microgravity, but is inevitable during clinostatting, and may be perceived by cells if rotation is not fast enough. To test the effect of clinostatting on root cells and development, lettuce seedlings were germinated and grown for two weeks in a spacetron, keeping the centrifugation rate at zero. In the clinorotated plants, amyloplasts were distributed throughout the cells and were not sedimented as in the stationary control. Cells of seedlings grown in a spacetron have significantly different ultrastructures from those grown under control conditions of 1g.

• Journal of environmental and Sanitary engineering
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• v.10 no.3
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• pp.35-44
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• 1995

This study was carried out in order to compare the methods for Salmonella spp. isolation from sewage and to settle the most appropriate conditions for that isolation. The direct enrichment method was more effective than the pre- enrichment method for Salmonella spp. isolation. The rate of detection was much higher when the specimens were enriched at $41.5^{\circ}C$ than when at $35^{\circ}C$. Usage of XLBG agar medium showed better results for Salmonella isolation than that of SS medium. It can be suggested that the most effective combination for Salmonella spp. isolation was the direct centrifugation(3,000 rpm 100m1)- direct enrichment($41.5^{\circ}$C)-usage of XLBG medium.

• Korean Journal of Veterinary Research
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• v.32 no.2
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• pp.245-250
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• 1992

This study was performed to demonstrate the presence of large granular lymphocyte(LGL) in Sprague-Dawley(SD) rats and morphologically observe NK cell and also establish the method of isolation of natural killer cell in SD rats. By percoll discontinuous density gradients centrifugation, highly enriched LGL population were shown to fraction 2(border line between 44.2% and 50.8%). LGL were shown to bind selectively to YAC1 mouse lymphoma cell. This fraction expressed very high NK cell cytolysis. Therefore, we thought that LGL have NK activity in SD rats. The Morphology of rat LGL is very similar to that of human LGL. These cells have an eccentric kidney-shaped nucleus. Their most distinctive feature was their cytoplasmic azurophilic granules. Another distinguishing feature of rat LGL was their high cytoplasmic : nuclear ratio. It was concluded that LGL played a role part in mediating natural killer activity in this species.