• Preventive Nutrition and Food Science
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• 제9권3호
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• pp.276-282
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• 2004

Marginal Zn deficiency is prevalent through the world and yet human zinc status has not been properly assessed due to the lack of a reliable diagnostic indicator. One potential possibility for zinc status assessment using Zn-binding protein, metallothionein (MT)-mRNA, has been proposed. The purpose of the present study was aimed to show whether measurement of mononuclear cell (MNC) MT mRNA, using a competitive-reverse transcriptase-polymerase chain reaction (competitive-RT-PCR) assay, could indicate zinc status in human subjects. In this study, MNC MT-mRNA expression was measured using a competitive-RT-PCR to compare before and after 14 days of zinc supplementation (50 mg Zn/das zinc gluconate). RT-PCR oligonucleotide primers which were designed to amplify both a 278 bp segment of the human MT-2A cDNA and a 198 bp mutant competitor cDNA template from MNCs, were prepared. MT-2A mRNA was normalized by reference to the housekeeping gene, $\beta$-actin, mRNA for which was also measured by competitive-RT-PCR. There was considerable inter-individual variation in MT-mRNA concentration and yet, the mean MT-2A mRNA level increased 4.7-fold after Zn supplementation, as compared to before Zn supplementation. This MT-2A mRNA level was shown as the same pattern and, even more sensitive assay, compared to the conventional plasma and red blood cells (RBCs) Zn assessment in which plasma and RBCs zinc levels increased 2.3- and 1.2-fold, respectively (p<0.05). We suggest that MT competitive-RT-PCR can be a useful assessment tool for evaluating human zinc status.

• 한국환경과학회지
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• 제20권8호
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• pp.929-942
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• 2011

A novel conductivity technique was developed to detect penetration depth of the vessel fluid into the feedpipe. For a given reactor geometry, critical agitator speeds were experimentally determined at the onset of feedpipe backmixing using Rushton 6 bladed disk turbine (6BD) and high efficiency axial flow type 3 bladed (HE-3) impellers. The ratio of the feedpipe velocity to the critical agitator speed ($v_f/v_t$) was constant for either laminar or turbulent feedpipe flow regimes. Compared to the results of fast competitive reaction, feedpipe backmixing had to penetrate at least one feedpipe diameter into the feedpipe to significantly influence the yield of the side product. However, higher $v_f/v_t$ than that for L/d = 0 (position at the feedpipe end) of the conductivity technique is recommended to completely eliminate feedpipe backmixing in conservative design criteria. The conductivity technique was successful in all feedpipe flow conditions of laminar, transitional and turbulent flow regimes.

• Journal of Microbiology and Biotechnology
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• 제12권5호
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• pp.801-806
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• 2002

A multiplex competitive polymerase chain reaction (PCR) method was developed for the rapid identification and quantification of Leuconostoc mesnteroides and Lactobacillus plantarum populations which are the key microorganisms in kimchi fermentation. The strain-specific primers were designed to selectively amplify the target genes encoding 165 rRNA of L. plantarum and dextransucrase of L. mesenteroides. There was a linear relationship between the band intensity of PCR products and the number of colony forming units of each model organism. The PCR quantification method was compared with a traditional plate-counting method f3r the enumeration of the two lactic acid bacteria in a mixed suspension culture and also applied to a real food system, namely, watery kimchi. The population dynamics of the two model organisms in the mixed culture were reliably predictable by the competitive PCR analysis.

• 대한전기학회논문지
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• 제45권2호
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• pp.242-248
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• 1996

The properties of TiN/TiSi$_{2}$ bilayer formed by a rapid thermal annealing is investigated when thin SiO$_{2}$ film exists at the Ti-Si interface. The competitive reaction for the TiN/TiSi_2 bilayer occurs above 600 .deg. C. The thickness of the TiSi$_{2}$ layer decreases with increasing SiO$_{2}$ film thickness and also decreases with increasing anneal temperture When the competitive reaction for the TiN/TiSi$_{2}$ bilayer is occured by rapid thermal annealing, the composition of TiN layer represents TiN$_{x}$O$_{y}$ due to the SiO$_{2}$ layer at the Ti-Si interface but the structures of the TiN and TiSi$_{2}$ layers were not changed.d.d.

• 한국미생물·생명공학회지
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• 제9권4호
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• pp.179-183
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• 1981

진균류의 세포벽제거 및 이에 따른 protoplast생성 등에 많이 이용되어지고 있는 chitinase를 Streptomyces sp. 115-5 균주로부터 생산하여 순수 정제한 다음, 이 chitinase의 작용을 저해하는 포도당의 저해양상을 조사하였다. 포도당 외에 D-glucuronic acid, D-sorbitol및 D-xylose등도 chitinase의 활성을 저해하였다. 그런고로, 포도당 분자에 의한chitinase의 활성 저해 효과에는 위의 분자들의 공통부분인 2번, 3번 및 4번 탄소의 hydroxyl group들의 구조위치가 중요한 영향을 가진다는 것을 알 수 있다. 그리고 포도당에 의한 chitinase의 저해양상은 competitive inhibition 과 non-competitive inhibition 과의 혼합 저해형으로 나타났다.

• Archives of Pharmacal Research
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• 제26권9호
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• pp.667-678
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• 2003

We examined the effect of p-substituents in p-substituted cinnamyl methyl ethers and 1-(p-substituted phenyl)allyl methyl ethers with CSI, and confirmed that the CSI reaction of allyl ethers (p-substituted ethers) is a competitive reaction of $S_Ni{\;}and{\;}S_N1$ mechanism according to the stability of the carbocation. And, the only terminal allylic amine was obtained through the migration reaction in thermodynamic reaction condition.

• Journal of Microbiology
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• 제40권1호
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• pp.33-37
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• 2002

An enzymatic reaction for the production of D-alanine from D-aspartic acid and pyruvate as substrates by a thermostable D-amino acid aminotransferase (D-AAT) was investigated at various conditions In the temperature range of 40-70$\^{C}$ and pH range of 6.0-9.5. The D-AAT was produced with recombinant E. coli BL21, which hosted the chimeric plasmid pTLK2 harboring the D-AAT from the novel thermophilic Bacillus sp. LK-2. The enzyme reaction was shown to follow the Ping Pong Bi Bi mechanism. The K$\_$m/ values for D-aspartic acid and pyruvate were 4.38 mar and 0.72 mM, respectively. It was observed that competitive inhibition by D-alanine, the product of this reaction, was evident with the inhibition constant K$\_$i/ value of 0.1 mM. A unique feature of this reaction scheme is that the decorboxylation of oxaloacetic acid, one of the products, spontaneously produces pyruvate. Therefore, only a catalytic amount of pyruvate is necessary for the enzyme conversion reaction to proceed. A typical time-course kinetic study skewed that D-alanine up to 88 mM could be produced from 100 mM of D-aspartic acid with a molar yield of 1.0.

• Food Science and Biotechnology
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• 제14권3호
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• pp.387-391
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• 2005

Competitive polymerase chain reaction (cPCR) was used to develop a direct enumeration method of Listeria monocytogenes in pork meat. Pork meat was artificially inoculated with L. monocytogenes and DNA was extracted using guanidine thiocyanate-phenol-chloroform and subjected to PCR amplification. Sixteen primer sets for L. monocytogenes hlyA gene were tested for sensitive detection and the DG69/DG74 primer set was selected. The detection limit achieved with this primer set was as low as 860 colony-forming units (cfu) per 0.1 g of pork meat. When the samples were cultured at $30^{\circ}C$ for 16 hr in Brain Heart Infusion (BHI) medium, even a single bacterium could be detected with this primer set by PCR. For cPCR, the hlyA gene, which features a 148 bp-deletion, was cloned in the pGEM-4Z vector. A known amount of competitor DNA which has the same primer binding sites was co-amplified with L. monocytogenes total DNA from the artificially inoculated pork meat. The cell-number determined by cPCR was approximately equal to cfu from the Most Probable Number (MPN) method. The whole procedure took only 5 hr.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.239.2-240
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• 2003

We have recently described the novel synthetic method for N-protected amines from various ethers using chlorosulfonyl isocyanate(CSI) and found that the mechanism of our CSI reaction is a competitive reaction of SN1 and SNi mechanism according to the stability of carbocation intermediate. Forthermore. we developed the regioselective and diastereoselective one-pot synthetic method for 1,2-amino alcohol, through the reaction of di-and tribenzyl thers with CSI, and invetigated its mechanism. (omitted)

• 대한화학회지
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• 제56권1호
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• pp.14-19
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• 2012

We investigate the doublet and quartet potential energy surfaces associated with the gas-phase reaction between $Ti^+$ and $CF_3COCH_3$ for two plausible reaction pathways, $TiF_2^+$ and $TiO^+$ formation pathways by using the density functional theory (DFT) method. The molecular structures of intermediates and transition states involved in these reaction pathways are optimized at the DFT level by using the PBE0 functional. All transition states are identified by using the intrinsic reaction coordinate (IRC) method, and the resulting reaction coordinates describe how $Ti^+$ activates $CF_3COCH_3$ and produces $TiF_2^+$ and $TiO^+$ as products. On the basis of presented results, we propose the most favorable reaction pathway in the reaction between $Ti^+$ and $CF_3COCH_3$.