• BMB Reports
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• v.30 no.1
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• pp.60-65
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• 1997

Expression of human Cu.Zn-superoxide dismutase (SOD) with activity comparable to human erythrocyte enzyme was achieved in E. coli B21(DE3) by using the pET-17b expression vector containing a T7 promoter. Recombinant human SOD was found in the cytosol of disrupted bacterial cells and represented > 25% of the total bacterial proteins. The protein produced by the E. coli cells was purified using a combination of ammonium sulfate precipitation, Sephacryl S-100 gel filtration and DEAE-Sephacel ion exchange chromatography. The recombinant Cu,Zn-SOD and human erythrocyte enzyme were compared using dismutation activity, SDS-PAGE and immunoblotting analysis. The mass of the subunits was determined to be 15,809 by using a electrospray mass spectrometer. The copper specific chelator. diethyldithiocarbamate (DOC) reacted with the recombinant Cu,Zn-SOD. At $50{\mu}M$ and $100{\mu}M$ concentrations of DOC, the dismutation activity was not inhibited for one hour but gradually reduced after one hour. This result suggests that the reaction of DOC with the enzyme occurred in two distinct phases (phase I and phase II). During phase I of this reaction, one DOC reacted with the copper center, with retention of the dismutation activity while the second DOC displaced the copper, with a loss of activity in phase II.

• Korean Journal of Applied Biomechanics
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• v.23 no.2
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• pp.131-139
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• 2013

Naejirgi is one of the fastest, most forceful and most often being used kicks in Taekkyon games, The purpose of this study was to investigate kinetic factors on two types of Naejirgi kick, one of which uses knee bending of supporting leg and the other uses little it. 12 taekkyoners (11 males and one female) who are the students of Y University participated in this study. They have been practicing on Taekkyon for five years or more. Positions of CoM, the elapsed time of each phase, vertical ground reaction forces, joint moments and impulses of supporting leg were analyzed for this study. The results were as follows; in Naejirgi with knee bending of supporting leg than without knee bending of supporting leg, the vertical motion range of whole body CoM was larger during phase 2 and 3, the elapsed time of phase 4 were longer, players stayed longer in the nearest location to opponent, during phase 4 the vertical ground reaction forces of supporting foot were larger, and joint extension moments and angular impulses of supporting leg (especially knee) were larger. In conclusion supporting knee bending is not a useful strategy for Naejirgi, because players stay longer in the nearest position to opponent and consumed more muscle force and energy for producing the vertical momentum which is unnecessary for pushing down the opponent.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.8
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• pp.1022-1030
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• 1999

A numerical study was carried out to analyze the effect of flow distribution of stirred part and plug flow part on combustion efficiency at the coal gasification process in an entrained bed coal reactor. The model of computation was based on gas phase eulerian balance equations of mass and momentum. The solid phase was described by lagrangian equations of motion. The $k-{\varepsilon}$ model was used to calculate the turbulence flow and eddy dissipation model was used to describe the gas phase reaction rate. The radiation was solved using a Monte-Carlo method. One-step parallel two reaction model was employed for the devolatilization process of a high volatile bituminous Kideco coal. The computations agreed well with the experiments, but the flame front was closer to the burner than the measured one. The flow distribution of a stirred part and a plug flow part in a reactor was a function of the magnitude of recirculation zone resulted from the swirl. The combustion efficiency was enhanced with decreasing stirred part and the maximum value was found around S=1.2, having the minimum stirred part. The combustion efficiency resulted from not only the flow distribution but also the particle residence time through the hot reaction zone of the stirred part, in particular for the weak swirl without IRZ(internal recirculation zone) and the long lifted flame.

• Archives of Pharmacal Research
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• v.22 no.6
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• pp.585-591
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• 1999

The linker which plays a role in connecting a polymer with a scaffold has become an important part n solid-phase reaction. To develop a new linker for alcohols and carbohydrates, dihydropyran moiety was selected in this study. New linker, 1-($4^{l},5^{l}$-dihydro-5H-pyranyl)-7-hydroxyheptan-3-one (5) was synthesized via four steps from $\delta$-valerolactone. This can be called as DDHP-linked Wang resin due to double dihy-dropyran rings. To the one pyran ring of new linker 5 was added Wang resin and other alcohols and carbohydrates as scaffolds were then added successfully to the another pyran ring. Carbohydrate and hydroxyl resins were connected via new linker in a 70% loading yield. The detachment of glucose moiety in the presence of PPTS (2 equiv.) in 1:1 n-buteanol/1,2-dichloroethane at $60^{\circ}C$ for 12 h was carried out quantitatively. When certain combinatorial chemical works are carried out using this dihydropyran linker, Wang resin itself can be recovered. Its fact is particularly very important in industry, because recovered resins can be recycled.

• Korean Security Journal
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• no.19
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• pp.207-223
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• 2009

The main purpose of this study was to analyze the reaction time of body guards in different stances to provide quantification of data for educational use. There were 4 martial art trained body guards participating in this study. The results of the EMG analysis and reaction time are as follows. The average reaction time of the whole body was $1.38{\pm}0.07$ seconds. In the first phase the reaction to the signal was $0.22{\pm}0.02$ seconds while in the second phase the reaction after checking was $0.62{\pm}0.10$ seconds, which produced the largest impulse. the reaction times of the third and fourth phase were gradually reduced, $0.29{\pm}0.02$ seconds and $0.26{\pm}0.02$ seconds consecutively. In the body guard posture the following muscles had a high activity level; phase one the right and left of the tibialis anterior muscle, phase two the right and left of the tibialis anterior muscle and the right of the gastrocnemius, phase three the right side of the tibialis anterior and gastrocnemius, phase four the left and right of the biceps femoris and the right side of the rectus femoris. In the first and second phase the shank muscles were used a lot, whereas in the third and fourth phase the shank and thigh muscles were used a lot showing the overall muscle activation of the lower limbs.

• Bulletin of the Korean Chemical Society
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• v.19 no.9
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• pp.993-999
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• 1998

Acid catalyzed hydrolysis of 1-phenoxyethyl propionate, Ⅰ, has been studied using the PM3 method in the gas phase. The first step of the reaction is the protonation of basic sites, three different oxygens in Ⅰ, producing three protonated species Ⅱ, Ⅲ and Ⅳ. All possible reaction pathways have been studied from each protonated structure. Changes in the reaction mechanisms have also been discussed from the results obtained by varying a nucleophile from a water monomer to a water dimer to a complex between one water molecule and an intermediate product (propionic acid or phenol) produced in the preceding unimolecular dissociation processes. Minimum energy reaction pathway is 2-W among the possible pathways, in which water dimer acts as an active catalyst and therefore facilitates the formation of a six-membered cyclic transition state. Lower barrier of 2-W is ascribed to an efficient bifunctional catalytic effect of water molecules. PM3-SM3.1 single point calculations have been done at the gas-phase optimized structure (SM3.1/PM3//PM3) to compare theoretical results to those of experimental work.

• Asian Journal of Atmospheric Environment
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• v.9 no.2
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• pp.158-164
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• 2015

The estimation of the concentration of hydroxyl radical (OH) in the atmosphere is essential to build atmospheric models and to understand the mechanisms of the reactions involved in OH. Although water vapor is one of the most abundant species in the troposphere, only a few studies have been performed for the reaction of OH and water vapor. Here I demonstrate an ab initio study on the complex forming reation of OH with $H_2O$ in the gas phase performed based on density functional theory to calculate the reaction rate and the energy states of the reactant and the OH-$H_2O$ complex. The structure of the complex, which belongs to the Cs point group, was optimized at global minima. The transition state was not found at the B3LYP and MP2 levels of theory. Rate constants of the forward and the reverse reactions were calculated as $1.1{\times}10^{-16}cm^3\;molecule^{-1}\;s^{-1}$ and $5.3{\times}10^9\;s^{-1}$, respectively. The extremely slow rates of complex forming reaction and the resulting hydrogen atom exchange reaction of OH and $H_2O$, which are consistent with experimentally determined values, imply a negligible possibility of a change in OH reactivity through the title reaction.

• BMB Reports
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• v.29 no.3
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• pp.215-220
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• 1996

A general procedure to quantitate the reaction of carbodiimides with carboxy groups of proteins is described. Pyridoxamine reacts with the o-acylisourea intermediate generated during the reaction of carboxyl residues with carbodiimides. The extent of the reaction is determined by measuring the spectroscopic properties, absorption and emission, of pyridoxyl residues covalently attached to the proteins. Resolved pig brain aspartate aminotransferase (apoenzyme), inactivated by 1-ethyl-3-(3-dimethylamino propyl) carbodiimide, reacts with $[^{3}H]pyridoxamine$. After trypsin digestion, one peptide labeled with radioactive pyridoxyl was separated by reverse phase HPLC.

• Journal of the Korean Applied Science and Technology
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• v.6 no.2
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• pp.29-37
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• 1989

Using the quarternary ammonium salts as phase transfer catalyst, the nucleophilic substitution reaction of 1-chlorooctane with sodium-cyanide was investigate kinetically with respect to the formation of octanenitrile. The product was analyzed with gas chromatograph, and quantity of octanenitrile was measured. The reaction condition was considered by the effect of the reaction temperature, of the species and the amount of catalyst, of the speed of strirring, and of the concentration of reactants. The reaction was carried out in the first order on the concentration of 1-chlorooctane and sodium cyanide, respectively. The over-all order was 2nd. The activation energies for the nucleophilic substitution reaction of 1-chlorooctane and 1-bromooctane under tetrabutylammonium hydrogen-sulfate were calculated as 2.05 and 10.08kcal/mol, respectively. The effect of various caltalysts was decreased in the order of tetrabutylammonium bromide, terabutylammonium, tetrabutylammonium hydrogensulfate, and tetrabutylammonium iodide. The reaction rate was dependent on the concentration of sodium-cyanide dissolved in the aqueous phase, and the good result was shown when the mol ratio between 1-chlorooctane and sodium cyanide was one per three.

• Journal of the Korean Chemical Society
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• v.57 no.6
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• pp.684-690
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• 2013

Since a glycerol molecule has three active sites, two ${\alpha}$ and one ${\beta}$ hydroxyl groups; it undergoes condensation by releasing water molecules to produce linear, nonlinear and heterocyclic oligomers. The Gibbs free energy (G), enthalpy (H) and internal energy (E) of 7 diglycerol, 15 triglycerol and 23 tetraglycerol isomers were calculated at B3LYP level of theory using 6-311++G(d, p) basis set, in both gas and aqueous phases. Linear oligomers, ${\alpha}{\alpha}$-diglycerol, ${\alpha}{\alpha}$, ${\alpha}{\alpha}$-triglycerol and ${\alpha}{\alpha}$, ${\alpha}{\alpha}$, ${\alpha}{\alpha}$-tetraglycerol, were found to be the most stable oligomers in aqueous phase. It was found that the stability of cyclic oligomers decreases as the size of their rings increases. Cyclic oligomers are produced by dehydration of the acyclic ones which is an endothermic reaction while its ${\Delta}G$ is negative. The dehydration reaction is less endothermic in aqueous phase.