• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1995.04a
• /
• pp.74-74
• /
• 1995

GABA transaminase is inactivated by preincubation with p$^1$, p$^2$-bis(5'-pyridoxal) diphosphate at pH 7.0. The inactivation under pseudo-first order conditions proceeds at a slow rate (K$\_$obs/=0.035 min$\^$-1/). The degree of labeling of the enzyme by p$^1$, p$^2$-bis(5'-pyridoxal) diphosphate was determined by absorption spectroscopy, The blocking of 2 lysyl residues/dimer is needed for inactivation of the transaminase. The time course of the reaction is significantly affected by the substrate ${\alpha}$-ketoglutarate, which afforded complete protection against the loss of the catalytic activity. Whereas cofator pyridoxal phosphate failed to prevent the inactivation of the enzyme. Therefore, it is postulated that binding of ${\alpha}$-ketoglutarate tn lysyl residues is the major factor contributing to stabilization of the catalytic site and bifuctional reagent p$^1$, p$^2$bis(5'-pyridoxal) diphosphate blocks lysyl residues other than those involved in the binding of the cofactor.

• Journal of the Korean Chemical Society
• /
• v.39 no.8
• /
• pp.643-649
• /
• 1995

The Menschutkin type reactions of substituted(Z)-benzyl systems with substituted(Y)-pyridines and N,N-dimethyl aniline have been studied by the electro-conductometric method in acetonitrile at 35$^{\circ}C$ and 50$^{\circ}C$. On the plot of $k_{obs}$ versus concentrations of nucleophile under pseudo-first order conditions, 3,$4-(CH_3/O)_2$-benzyl bromide and $4-CH_3O$-benzyl bromide were a positive intercept at zero concentration of nucleophile. The $k_1$ value for each compound was invariant with the different nucleoephile. However, $4-CH_3-$ and other electron withdrawing substituents of benzyl bromides did not show the positive intercept. These results are suggested that the reactions have been proceeding simultaneously and independently for the activated benzyl bromides via direct bimolecular and intimate ion pair intermediate.

• Journal of Oriental Neuropsychiatry
• /
• v.29 no.2
• /
• pp.69-77
• /
• 2018

Objectives: To determine the relationship between 2D:4D ratio and Minnesota Multiphasic Personality Inventory-2 Questionnaire (MMPI-2 scales). Methods: The 2D:4D ratio in 101 Korean medical students was measured. MMPI-2 test was performed. Results: In the unisex group, there were significantly positive correlations between the 2D:4D ratio and MMPI-2 scales of Hs, D, Pt, Sc, Si, RC1, RC2, RC8, INTR, ANX, OBS, HEA, BIZ, LSE, WRK, TRT, A, R, Mt, PK, and AAS while there were significantly negative correlations between the 2D:4D ratio and MMPI-2 scales of Es and Do. In the male group, there were significantly positive correlations between the 2D:4D ratio and MMPI-2 scales of Hs, RC1, RC8, HEA, and AAS while there were significantly negative correlations between the 2D:4D ratio and MMPI-2 scale of AGGR. In the female group, the 2D:4D ratio showed significantly positive correlations with MMPI-2 scales of Pt, Sc, Si, RC1, RC2, RC6, INTR, DEP, BIZ, LSE, WRK, A, Mt, PK, and Ho while it showed significantly negative correlations with MMPI-2 scale of Do. Conclusions: MMPI-2 scales are correlated with the 2D: 4D ratio. Therefore, 2D: 4D ratio could be used as an indicator to reflect multiphasic personality of individuals.

• Journal of Soil and Groundwater Environment
• /
• v.20 no.6
• /
• pp.117-126
• /
• 2015

Reductive degradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) by nanoscale zero-valent iron (nZVI) was investigated to evaluate the feasibility of using it for in-situ groundwater remediation. Batch experiments were conducted to quantify the kinetics and efficiency of RDX removal by nZVI, and to determine the effects of pH, dissolved oxygen (DO), and ionic strength on this process. Experimental results showed that the reduction of RDX by nZVI followed pseudo-first order kinetics with the observed rate constant (k_obs) in the range of 0.0056-0.0192 min⁻¹. Column tests were conducted to quantify the removal of RDX by nZVI under real groundwater conditions and evaluate the potential efficacy of nZVI for this purpose in real conditions. In column experiment, RDX removal capacity of nZVI was determined to be 82,500 mg/kg nZVI. pH, oxidation-reduction potential (ORP), and DO concentration varied significantly during the column experiments; the occurrence of these changes suggests that monitoring these quantities may be useful in evaluation of the reactivity of nZVI, because the most critical mechanisms for RDX removal are based on the chemical reduction reactions. These results revealed that nZVI can significantly degrade RDX and that use of nZVI could be an effective method for in-situ remediation of RDX-contaminated groundwater.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.3B
• /
• pp.72-84
• /
• 2005

Optical burst switching networks usually employ one-way reservation by sending a burst control packet with a specific offset time, before transmitting each data burst Same. Due to such a Property, burst-contentions occur when multiple bursts contend for the same wavelength in the same output link simultaneously in a node, leading to burst losses, eventually degrading the quality of service. Therefore, in this paper, we propose a dynamic routing algorithm using minimum local state information in order to decrease burst-contentions. In this proposed scheme, if burst loss rate exceeds a threshold value at a certain node, a new alternative routing path is chosen according to burst priority and location of burst generation, which enables the contending bursts to detour around the congested link. Moreover, for reducing the effect of sending bursts on the primary path due to the alternative path, we also apply a minimum path-cost based routing on link-cost concept. Our simulation results show that proposed scheme improves the network performance in terms of burst loss probability and throughput by comparing with conventional one.

• Journal of Environmental Science International
• /
• v.25 no.4
• /
• pp.517-524
• /
• 2016

In order to treat groundwater containing high levels of nitrate, nitrate reduction by nano sized zero-valent iron (nZVI) was studied using batch experiments. Compared to nitrate removal efficiencies at different mass ratios of $nitrate/Fe^0$, the removal efficiency at the mass ratio of 0.02% was the highest(54.59%). To enhance nitrate removal efficiency, surface modification of nZVI was performed using metallic catalysis such as Pd, Ni and Cu. Nitrate removal efficiency by Cu-nZVI (at $catalyst/Fe^0$ mass ratio of 0.1%) was 66.34%. It showed that the removal efficiency of Cu-nZVI was greater than that of the other catalysts. The observed rate constant ($k_{obs}$) of nitrate reduction by Cu-nZVI was estimated to $0.7501min^{-1}$ at the Cu/Fe mass ratio of 0.1%. On the other hand, TEM images showed that the average particle sizes of synthetic nZVI and Cu-nZVI were 40~60 and 80~100 nm, respectively. The results imply that catalyst effects may be more important than particle size effects in the enhancement of nitrate reduction by nZVI.

• Journal of The Korean Astronomical Society
• /
• v.47 no.6
• /
• pp.303-309
• /
• 2014

We present results of our investigation of the radio intrinsic brightness temperatures of compact radio jets. The intrinsic brightness temperatures of about 100 compact radio jets at 2, 5, 8, 15, and 86 GHz are estimated based on large VLBI surveys conducted in 2001-2003 (or in 1996 for the 5 GHz sample). The multi-frequency intrinsic brightness temperatures of the sample of jets are determined by a statistical method relating the observed brightness temperatures with the maximal apparent jet speeds, assuming one representative intrinsic brightness temperature for a sample of jets at each observing frequency. By investigating the observed brightness temperatures at 15 GHz in multiple epochs, we find that the determination of the intrinsic brightness temperature for our sample is affected by the flux density variability of individual jets at time scales of a few years. This implies that it is important to use contemporaneous VLBI observations for the multi-frequency analysis of intrinsic brightness temperatures. Since our analysis is based on the VLBI observations conducted in 2001-2003, the results are not strongly affected by the flux density variability. We find that the intrinsic brightness temperature $T_0$ increases as $T_0{\propto}{\nu}^{\xi}_{obs}$ with ${\xi}=0.7$ below a critical frequency ${\nu}_c{\approx}9GHz$ where the energy loss begins to dominate the emission. Above ${\nu}_c$, $T_0$ decreases with ${\xi}=-1.2$, supporting the decelerating jet model or particle cascade model. We also find that the peak value of $T_0{\approx}3.4{\times}10^{10}$ K is close to the equipartition temperature, implying that the VLBI cores observable at 2-86 GHz may be representing jet regions where the magnetic field energy dominates the total energy in jets.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.13 no.6
• /
• pp.1065-1071
• /
• 2009

Satellite application services can be divided into realtime services like voice communications and non-real time services like traditional data communications. To support both types of services on the same On-Board Switching(OBS), a scheduler which depends on their service classes is required. A fixed priority scheduling policy has a starvation problem. In this paper we propose a scheduling scheme based on premium and age. Premium is a fixed value which is given to a certain class of services. Age is another parameter of the scheduling policy and it will be increased by one for every scheduling cycle. The scheme we propose chooses a packet which has the largest sum of its age and premium. Simulation results indicate that the proposed approach shows better performance in both average cell delay and std-dev of cell delay for the lower class of service. There is no staying in infinite starvation state.

• Korean Journal of Community Nutrition
• /
• v.8 no.4
• /
• pp.538-546
• /
• 2003

This study was carried out to figure out the dietary intake of pregnant women in Daegu area. A total of 467 pregnant women was recruited at two hospitals in this area to collect the information on dietary intakes, general characteristics, and anthropometric measurements using an interview. Forty-seven women (10.1%) were in the first trimester, 101 women (21.6%) in the second trimester, and 319 women (68.3%) in the third trimester. The mean age, prepregnant weight and height of subjects were not significantly different among the trimester groups. The mean daily nutrient intakes of energy, fat, protein, carbohydrates, phosphate, sodium, vitamin B$_1$, vitamin B$_2$, and vitamin C were significantly different among the trimester groups, but the other nutrients were not different. For the calcium and iron, the percentage of subjects consumed less than 75% of the Korean RDA was over 80%, and for other nutrients such as energy, vitamin B$_1$, and vitamin B$_2$ over 50% of subjects consumed less than 75% of the Korean RDA in the first trimester. The correlations between nutrient intakes and weight gain during pregnancy showed different patterns among the trimester groups. The mean adequacy ratio and dietary variety scores were not significantly different among the trimester groups. The amount of food intake from cereals and cereal products were higher during the second and the third trimester compared to the first trimester, but those of the other food groups were not significantly different. In conclusion, nutrient intakes of the pregnant women for iron, calcium and some vitamins were inadequate and nutritional management programs for these nutrients are necessary. (Korean J Community Nutrition 8(4) : 538-546, 2003)

• Journal of Embryo Transfer
• /
• v.27 no.3
• /
• pp.183-187
• /
• 2012

Adult stem cell transplantation has been increased every year, because of the lack of organ donors for regenerative medicine. Therefore, development of reliable and safety cryopreservation and bio-baking method for stem cell therapy is urgently needed. The present study investigated safety of dimethyl sulfoxide (DMSO) such as common cryoprotectant on porcine bone marrow derived mesenchymal stem cells (pBM-MSCs) by evaluating the activation of Caspase-3 and -7, apoptosis related important signal pathway. pBM-MSCs used for the present study were isolated density gradient method by Ficoll-Paque Plus and cultured in A-DMEM supplemented 10% FBS at $38.5^{\circ}C$ in 5% $CO_2$ incubator. pBM-MSCs were cryopreserved in A-DMEM supplemented either with 5%, 10% or 20% DMSO by cooling rate at $-1^{\circ}C$/min in a Kryo 360 (planner 300, Middlesex, UK) and kept into $LN_2$. Survival rate of cells after thawing did not differ between 5% and 10% DMSO but was lowest in 20% DMSO by 0.4% trypan blue exclusion. Activation of Caspase-3 and -7 by Vybrant FAM Caspase-3 and -7 Assay Assay Kit (Molecular probes, Inc.OR, USA) was analyzed with a flow cytometer. Both of cryopreserved and control groups (fresh pBM-MSCs) were observed after the activation of Caspase-3 and -7. The activation did not differ between 5% and 10% DMSO, but was observed highest in 20% DMSO. Therefore 5% DMSO can be possibly used for cell cryopreservation instead of 10% DMSO.