• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.4
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• pp.458-468
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• 2007

To tolerate environmentally adverse conditions such as cold, drought, and salinity, plants often synthesize and accumulate proline in cells as compatible osmolytes. ${\Delta}^1$-Pyrroline-5-carboxylate synthetase(P5CS) catalyzes the rate-limiting step of proline biosynthesis from glutamate. Two complete genes, MtP5CS1 and MtP5CS2, were isolated from the model legume Medicago truncatula by cDNA cloning and bacterial artificial chromosome library screening. Nucleotide sequence analysis showed that both genes consisted of 20 exons and 19 introns. Alignment of the predicted amino acid sequences revealed high similarities with P5CS proteins from other plant species. The two MtP5CS genes were expressed in response to high salt and low temperature treatments. Semi-quantitative reverse transcription-polymerase chain reaction showed that MtP5CS1 was expressed earlier than MtP5CS2, indicating differential regulation of the two genes. To evaluate the reverse genetic effects of nucleotide changes on MtP5CS function, a Targeting Induced Local Lesions in Genomes approach was taken. Three mutants each were isolated for MtP5CS1 and MtP5CS2, of which a P5CS2 nonsense mutant carrying a codon change from arginine to stop was expected to bring translation to premature termination. These provide a valuable genetic resource with which to determine the function of the P5CS genes in environmental stress responses of legume crops.

• Analytical Science and Technology
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• v.18 no.3
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• pp.224-231
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• 2005

In this study, the optimum conditions for the LPME (liquid phase microextraction) were investigated to overcome several shortcomings of traditional liquid-liquid extraction method. The LPME, which is automatic and dynamic, was used to analyze the five pesticides (dementon-S-methyl, diazinon, parathion, fenitrothion, EPN) extracted from vegetable, and HP 6890 GC/NPD was used as an analytic instrument. It was possible to optimize the extraction condition using the automatic LPME. The optimum extraction rate was obtained at pH 3.0 and $100{\mu}g/mL$ of salt concentration and standard curve showed linearity with over $R^2=0.9921$ in the range of $0.2{\sim}10{\mu}g/g$. The relative standard deviations were 7.7%, 9.8%, 7.8%, 9.7% and 8.2% in the $5.0{\mu}g/g$ concentration of dementon-S-methyl, diazinon, parathion, fenitrothion and EPN, respectively. The acquired accuracies were satisfactory showing 12.7%, 7.8%, 10.4%, -6.7% and -0.7% for dementon-S-methyl, diazinon, parathion, fenitrothion and EPN respectively.

• Journal of the Korean Electrochemical Society
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• v.17 no.3
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• pp.156-163
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• 2014

In this study, we tried to improve the cycling performance of lithium-ion batteries by suppressing decomposition of the electrolyte solution containing fluorsilane-based additive. Trifluoropropyltrimethoxysilane was electrochemically oxidized and reduced prior to the decomposition of the liquid electrolyte composed of lithium salt and carbonate-based organic solvent. Thus, the stable solid electrolyte interphase (SEI) layer on both negative electrode and positive electrode was formed, and it was confirmed that the cycling performance of lithium-ion batteries assembled with electrolyte solution containing 5 wt.% trifluoropropyltrimethoxysilane was the mostly enhanced. The products formed on electrodes were analyzed by the SEM and XPS analysis, and it was demonstrated that trifluoropropyltrimethoxysilane can be one of the promising SEI-forming additives.

• Korean Journal of Materials Research
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• v.28 no.7
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• pp.423-427
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• 2018

For diamond/metal composites it is better to use diamond particles coated with metal carbide because of improved wettability between the diamond particles and the matrix. In this study, the coating of diamond particles with a chromium carbide layer is investigated. On heating diamond and chromium powders at $800{\sim}900^{\circ}C$ in molten salts of LiCl, KCl, $CaCl_2$, the diamond particles are coated with $Cr_7C_3$. The surfaces of the diamond powders are analyzed using X-ray diffraction and scanning electron microscopy. The average thickness of the $Cr_7C_3$ coating layers is calculated from the result of the particle size analysis. By using the molten salt method, the $Cr_7C_3$ coating layer is uniformly formed on the diamond particles at a relatively low temperature at which the graphitization of the diamond particles is avoided. Treatment temperatures are lower than those in the previously proposed methods. The coated layer is thickened with an increase in heating temperature up to $900^{\circ}C$. The coating reaction of the diamond particles with chromium carbide is much more rapid in $LiCl-KCl-CaCl_2$ molten salts than with the molten salts of $KCl-CaCl_2$.

• Journal of the East Asian Society of Dietary Life
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• v.24 no.6
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• pp.845-852
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• 2014

The quality of commercial sauce products was evaluated through pH, soluble solid content, salinity, water activity and microbial analyses. The pH of sauces was 2.38~5.30, soluble solids were between 6.03 and 71.67, and distributions of salt were 0.23~5.00% in 32 commercial sauce products. In addition, water activity of vinegar red pepper sauce and spicy soft tofu stew stock were determined 0.773 and 0.988, respectively. Yeast, mold, Staphylococcus aureus, E. coli and coliform were not detected in any sauces. Higher level of total viable cells (TVC) resulted in pH over 4.2. TVC of shelf-stable sauces was 1.0~3.6 log CFU/g. TVC of seven sauce products was classified as non-potentially hazardous foods by temperature controlled for safety standard (TCS), even though levels were over acceptable guidelines of the USDA (3 log CFU/g). These results indicate that the standard and classification of commercial sauce products should be modified and controlled strictly.

• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3444-3450
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• 2013

Three phase hollow fiber-liquid phase microextraction (HF-LPME), which is faster, simpler and uses a more environmentally friendly sample-preparation technique, was developed for the analysis of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) in human urine. For the effective simultaneous extraction/concentration of NSAIDs by three phase HF-LPME, parameters (such as extraction organic solvent, pH of donor/acceptor phase, stirring speed, salting-out effect, sample temperature, and extraction time) which influence the extraction efficiency were optimized. NSAIDs were extracted and concentrated from 4 mL of aqueous solution at pH 3 (donor phase) into dihexyl ether immobilized in the wall pores of a porous hollow fiber, and then extracted into the acceptor phase at pH 13 located in the lumen of the hollow fiber. After the extraction, 5 ${\mu}L$ of the acceptor phase was directly injected into the HPLC/UV system. Simultaneous chromatographic separation of seven NSAIDs was achieved on an Eclipse XDB-C18 (4.6 mm i.d. ${\times}$ 150 mm length, 5 ${\mu}m$ particle size) column using isocratic elution with 0.1% formic acid and methanol (30:70) at a HPLC-UV/Vis system. Under optimized conditions (extraction solvent, dihexyl ether; $pH_{donor}$, 3; $pH_{acceptor}$, 13; stirring speed, 1500 rpm; NaCl salt, 10%; sample temperature, $60^{\circ}C$; and extraction time, 45 min), enrichment factors (EF) were between 59 and 260. The limit of detection (LOD) and limit of quantitation (LOQ) in the spiked urine matrix were in the concentration range of 5-15 ng/mL and 15-45 ng/mL, respectively. The relative recovery and precision obtained were between 58 and 136% and below 15.7% RSD, respectively. The calibration curve was linear within the range of 0.015-0.96 ng/mL with the square of the correlation coefficient being more than 0.997. The established method can be used to analyse of NSAIDs of low concentration (ng/mL) in urine.

• Journal of the Korean Chemical Society
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• v.43 no.3
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• pp.307-314
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• 1999

Ml RNA, the RNA component of RNase P from Escherichia coli, is produced by 3' processing of pre-Ml RNA, a major primary transcript of the rnpB gene. The enzyme fraction containing the processing activity was partially purified and characterized. Since exposure of the active fraction to the high salt condition results in the inactivation of the processing activity, the processing enzyme seems to be an enzyme complex composed of multiple enzymes. The enzyme fraction loses the processing activity when treated with the chemical nuclease lead(II) ion, but regains its activity by the addition of RNA isolated from the enzyme fraction itself, suggesting that an RNA molecule(s) may be essential for the processing activity. Analysis of cleavage sites produced by the partially purified enzyme fraction also implies that the 3' processing occurs by multiple enzymes and at least in two distinct pathways.

• Journal of the Korean Chemical Society
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• v.37 no.12
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• pp.1060-1067
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• 1993

A series of New N-[1-(benzotriazol-1-yl)-X-substituted benzyl]-Y-substituted aniline derivaties (S) have been synthesized. And the rate of hydrolysis was investigated kinetically in 25% (v/v) aqueous methanol at 25$^{\circ}C$. On the basis of rate equations, solvent effect $m {\ll} 1,\; n \leq 3\; and\; m {\ll} l$), salt effect, general base catalysis, substituent effect (${\rho}_{xy}$ > > 0), and hydrolysis products analysis, it may be concluded that the hydrolysis of N-[1-(benzotriazol-1-yl)benzyl]aniline proceeds the "A-$S_N2$" mechanism below pH 12.0, while above pH 13.0, the hydrolysis proceeds through a typical "$S_N2$" mechanism.

• Elastomers and Composites
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• v.45 no.2
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• pp.100-105
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• 2010

An EPDM article was aged in air, distilled water, tap water, NaCl/$CaCl_2$ solution, and $CaCl_2/FeCl_3$ solution for 7 days. The aging temperature was $90^{\circ}C$. The samples aged in air and distilled water did not appear the whitening, those aged in tap water, NaCl/$CaCl_2$ solution, and $CaCl_2/FeCl_3$ solution showed the whitening. Soluble organic materials were analyzed using GC/MS to identify the whitening materials, surface morphology of the aged sample surface was examined using image analyzer and SEM, and elemental analysis of the materials accumulated on the sample surface was performed using EDX. Principal reason to cause whitening might be formation of metal salt of fatty acid by reaction between metal cation and fatty acid.

• The Korean Journal of Food And Nutrition
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• v.16 no.4
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• pp.353-358
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• 2003

Low salt-fermented product of alaska pollack roe were prepared tentatively and also discussed the retarding effect of fermentation period by vacuum. The results were as follows. The moisture content, pH and salinity decreased slightly, but the contents of VBN and total amino acids increased gradually during fermentation regardless of ripening types. pH and salinity showed little difference with ripening types, but moisture content was a little lower and the contents of VBN was some higher in non vacuum than those in vacuum, whereas total amino acid contents were greater in vacuum. In addition, total viable cell count were similar to trend of gentle decrement after increment to some degree but were higher in non vacuum than those in vacuum. Judging from the results of physicochemical analysis, it was showed that fermentation delayed in vacuum therefore it was considered that vacuum fermentation can be effective on shelf-life extension of jeot-gal.