• Microbiology and Biotechnology Letters
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• v.17 no.4
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• pp.358-364
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• 1989

A crystalline alkaline pretense- producing Streptomyce sp. YSA-130 was isolated from soil in alkaline medium(pH 10.5). The optimum culture condition of Streptomyce sp. YSA-130 for the production of alkaline protease was as follows; 2.0% soluble starch, 1.0% soytone, 0.3% $K_2$HPO$_4$, 0.02% MgSO$_4$.7$H_2O$, 0.8% Na$_2$CO$_3$, pH 10.5, 3$0^{\circ}C$, and 12 hr. The alkaline pretense from the culture broth of Streptomyce sp. YSA-130 was purified about 24 folds by ammonium sulfate precipitation , dialysis, DEAE-cellulose ion exchange chromatography, gel filtration on Sephadex G-15 and crystallization. Optimum temperature and pH of purified enzyme were 6$0^{\circ}C$, and 11.5. Temperature and pH stability of purified enzyme were 5$0^{\circ}C$, and 5.5-12.0. Calcium ion was effective to stabilize the enzyme at higher temperature. The molecular weight of the purified enzyme was approximately 30,000. The purified enzyme was inactivated by diisopropyl flurophosphate(DFP) but not affected by metal ion, EDTA, sulfhydryl reagent and stable detergent.

• Bulletin of the Korean Chemical Society
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• v.8 no.4
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• pp.276-280
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• 1987

Several chiral potassium B-alkyl-9-boratabicyclo[3.3.1]nonanes $(K\; B-R^*-9-BBNH)$ and potassium B-alkoxy-9-boratabicyclo[3.3.1]nonanes $(K \;B-OR^*-9-BBNH)$ were synthesized by treatment of the corresponding trialkylboranes and dialkylmonoalkoxyboranes with a small excess of potassium hydride. The chiral B-alkoxy derivatives generally reduce representative ketones, such as acetophenone and 3-methyl-2-butanone, with greater optical induction than the corresponding B-alkyl derivatives, suggesting the involvement of the oxygen atom in the control process for asymmetric synthesis.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.687-692
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• 2011

$^1H$ and $^{13}C$ NMR spectra of series of (E)-1-aryl-(2- and 3-thienyl)-2-propenones, that are aldol condensation products between 2- and 3-thiophenecarbaldehydes and m- and p-substituted acetophenones, were examined to make complete assignments of the chemical shifts. Long range couplings, $^4J$ and $^5J$, are observed in the $^1H-^1H$ COSY of both 2- and 3-thienyl compounds, which makes the elucidation of the conformation in solution possible. In contrast, the 2-furyl analogue shows the long range coupling phenomena, but the 3-furyl and phenyl analogues do not show similar phenomena.

• Journal of the Korean Chemical Society
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• v.52 no.1
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• pp.23-29
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• 2008

Simple Keggin type tungsten and molybdenum heteropoly acids, H3PW12O40 and H3PMo12O40, were usedas water-tolerant catalysts for the oxidation of alcohols with 34% hydrogen peroxide in normal drinking water. Accordingto our findings, H3PW12O40 may be used as a simple, effective, and cheap catalyst for this type of transformation in nor-mal drinking water with excelent yields. Efects of diferent solvents at 25-80oC and changing concentration of catalystand substrate on the reaction progress were also studied.

• Journal of the Korean Chemical Society
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• v.18 no.6
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• pp.408-414
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• 1974

The direct reactions of titanium tetrachloride with piperidine and diphenylamine in dichloromethane have been studied by examining the isolated reaction products. In the reaction with piperidine, titanium tetrachloride undergoes both addition and substitution reactions as in the following: $TiCl_4+C_5H_{10}NH{\to}TiCl_4{\cdot}C_5H_{10}NH$$TiCl_4+C_5H_{10}{\to}TiCl_3{\cdot}NC_5H_{10}+HCl$ The addition reaction is relatively fast and completed in minutes whereas the substitution reaction is very slow. The both reaction products coprecipitated with piperidine hydrochloride formed during the substitution reaction were isolated and characterized. The reaction with diphenylamine resembles to the above reaction but the addition compound could be obtained in pure crystal form.

• Korean journal of food and cookery science
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• v.25 no.1
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• pp.45-54
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• 2009

Contamination levels of aerobic colony counts, coliforms and pathogenic bacteria were tested in fried rice dishes to monitor quality for risk management. The prevalence of Bacillus cereus in dishes from 8 Chinese-style restaurants and 2 institutional foodservices was 10%, and the bacteria's contamination levels was 3.47 log CFU/g. Echerichia coli, Staphylococcus aureus, and Salmonella were not detected in any of the 10 samples. However, for their aerobic colony counts and numbers of isolated coliforms, the samples were 30% and 70% over the microbial criteria, respectively, for ready-to-eat foods presented in the Korean Food Code. This suggests that fried rice dishes, although cooked with oil at high temperature, require special care. For the prediction of the growth curve of B. cereus spp. in the fried rice samples, an experiment design of 3 storage temperatures ($7^{\circ}C$, $35^{\circ}C$, $57^{\circ}C$) x 5 storage times (0 h, 2 h, 4 h, 6 h, 24 h) was applied. The sample exposed to $35^{\circ}C$ showed no B. cereus spp. at 0 h; however, there was a tendency of slow growth (1.0 log CFU/g) after 4 hours of storage and then faster growth at 6 h (3.7 log CFU/g) and 12 h (4.7 log CFU/g), showing a growth rate of 0.56 log CFU/g/hr. These results indicate that fried rice, despite being heat-treated, can become heavily contaminated with B. cereus spp. when held over 2 hours at room temperature. However, the samples stored at $7^{\circ}C$ and $57^{\circ}C$ over 24 hours were not contaminated with B. cereus. Based on these results, management guidelines for controlling B. cereus are suggested.

• Journal of Powder Materials
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• v.4 no.3
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• pp.170-178
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• 1997

An investigation was performed to apply the M3/2 grade high speed steel for metal injection molding using both prealloyed and elementally blended powders. The injected samples were subjected to a debinding step in $H_2/N_2$ gas atmosphere at a ratio that affected the carbon content of the material. The carbon content ranged from 1.4wt.% to 1.43wt%. with increasing $H_2$ content up to 80% $H_2$ in $H_2/N_2$ atmosphere for the prealloyed powders. The carbon contents of the elementally blended powders exhibited 1.44wt.% and 1.62wt.% at 10% $H_2/N_2$ and 20% $H_2/N_2$ gas, respectively. This level decreased to 0.17wt.% upon increasing the $H_2$ content. The sintered density of both powders increased rapidly as the temperature reached the liquid phase forming temperature. After forming the liquid phase, the density rapidly increased to the optimum sintering temperature for the prealloyed powders, whereas the density of mixed elemental powders goes up slowly to the optimum sintering temperature. The optimum sintering temperature and density are 126$0^{\circ}C$ and 97.3% for the prealloyed powders and 128$0^{\circ}C$ and 96.9% for the elementally blended powders, respectively. The microstructure of the specimen at the optimum sintering temperature consisted of fine grains with primary carbides of MC and $M_6C$ type for the prealloyed powders. The elementally blended powders exhibited coarse grains with eutectic carbides of MC, $M_2C$ and $M_6C$ type.

• Korean Journal of Crystallography
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• v.2 no.2
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• pp.22-27
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• 1991

4-Amino-n-(2,6-dimethyk4-pyrimidnyl) benzenesulfonamide, C12H14N402. Unit cell parameters are a =12.626, b=11.262, c=9.375, a:b:r=90°, V =1333.07h3, D,at=1.390 g /cm3, and λ(Cu-Ka)=1.5418, The space group is Pca21, Orthorhombic. The final R factor of 1068 unique observed reflections is R=0.040. Two pair of molecules which related by symmetry operation has strong hydrogen bond. One is between H(N2) and N(3), and the other is H(NIA) and 0(1).

• Biomolecules & Therapeutics
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• v.2 no.1
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• pp.39-46
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• 1994

The present study was undertaken to demonstrate whether or not bradykinin activates a phospholipase D in rabbit kidney proximal tubule cells. By measuring the formation of [$^3$H]phosphatidic acid and [$^3$H]phosphatidylethanol we could elucidate the direct stimulation of phospholipase D by bradykinin. Bradykinin leads to a rapid increase in [$^3$H]phosphatidic acid and [$^3$H]diacylglycerol, and [$^3$H]phosphatidic acid formation preceded the formation of [$^3$H]diacylglycerol. This result suggests that some phosphatidic acid seems to be formed directly from phosphatidylcholine by the action of phospholipase D, not from diacylglycerol by the action of diacylglycerol kinase. In addition, the other mechanisms by which phospholipase D is activated was examined. We have found that phospholipase D was activated and regulated by extracellular calcium ion and pertussis toxin-insensitive G protein, respectively. It has also been shown that bradykinin may activate phospholipase D through protein kinase C-dependent pathway. In conclusion, we are now, for the first time, strongly suggesting that bradykinin-induced activation of phospholipase D in the rabbit kidney proximal tubule cells is mediated by a pertussis toxin-insensitive G protein and is dependent of protein kinase C.

• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.1
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• pp.171-178
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• 1999

Despite of decrease in shear and moment strengths, most steel structural designers use web openings in beams because of economical benefit and requirement. The purpose of this study is to suggest the method of reinforcement of H-shape steel beams with a rectangular web opening. If shear predominates over bending, it is necessary to consider all possible combinations of shear force and bending moment acting at the opening. In this paper, the ultimate strength and behavior of perforated beams have been investigated according to parameters (ratio of M/V, opening width within opening height ratio D/h, various reinforcing types A/B/C/D/M/N/W). The results of this study are as follows ; 1. Deformation of H-shape steel beams with a rectangular web opening was greatly affected by not only bending but also shear. 2. SB1-2/3 series have little difference in the reinforced efficiency, but SB1-2E/3E series have difference in the reinforced efficiency according to the reinforcement type. 3. Efficiency of SB1-2E/3E series is determined by reinforcing types, which RB1-2E-B/M/C and RB1-3E-M/D/C specimens have good efficient. Reinforcing type of perforated beams chooses efficient method according to ratio of M/V and D/h.