카드뮴의 중추신경계 독성유발 기전

이종화,장봉기,박종안,박종영,김완종,우기민 한국환경독성학회 2004 환경독성보건학회지 Vol.19 No.3

Although numerous studies have shown that cadmium disturbs the normal biological processes in central nervous system the mechanism of toxicity is not well understood The present study has investigated the effect of cadmium on oxidative stress, Na+/K- ATPase activity and the aggregation of amyloid beta peptide(β-amylotd) in neuronal cell Ime, HT22 cell LC_(5) and LC_(50) of cadmium for HT22 cell resulted from MTT assay was 4 1 μM and 9 5 μM, respectively Cadmium(2 to 8 μM) dose-dependently increased the lipid peroxidation and decreased the content of glutathione Cadmium 4 μM showed a significant decrease in Na^(-)/K^(+) ATPase activity as compared with control group The aggregation of P-amyloid was accelerated in a dose-dependent manner by the treatment with 2 to 8 μM cadmium These results suggest that the neurotoxicity of cadmium can be mediated by the increase in oxidative stress and decrease in Na^(-)/K^(+) ATPase activity.

카드뮴이 마우스 뇌에서 아연의 항상성에 관여하는 유전자발현에 미치는 영향

박종안,여은영,남상훈,장봉기,이종화,김완종 한국환경독성학회 2004 환경독성보건학회지 Vol.19 No.4

Metallothionein (MT), a small protein molecule which can bind of release metal tons, is involved in the regulation of cellular metal homeostasis This study was investigated the accumulation of cadmium in blood, tissue (liver, kidney and brain), and the effect of cadmium on several key genes (MT-Ⅰ, MT-Ⅱ, ZnT-1) in zinc metabolism m the mouse Mouses weighing 20-25g were randomly assigned to control and cadmium treated group (Cd group) Cd group was intraperitoneally injected with cadmium 2, 4, 8 mg/kg and control group was administerd with saline Mouses of each group were sacrificed by decapitation 4 hours after the administration of cadmium Cadmium contents in blood, fiver, kidney and brain were increased by a dose-dependent manner Accumulation of cadmium was mainly occurred in liver and kidney Induction of MT-I and MT-11 protein was increased, but ZnT-1 expression was decreased to a dose-dependent manner by the treatment of 2~8mg/kg cadmium These results suggested that cadmium can be transported to brain and alter the expression of several key genes in zinc homeostasis.

상수 원수에 따른 용존 유기물의 특성 평가

허준무,박종안,손부순,장봉기,이종화 한국환경과학회 1999 한국환경과학회지 Vol.8 No.3

This study was carried out to evaluate the characteristics of dissolved organics based on their origins, which were divided into two categories. The first group consisted of river, lake and secondary sewage treatment effluent, which were chosen as representative of their origins. The second group were artificial samples which were made of AHA(Aldrich humic acids) and WHA(Wako humic acids). Physicochemical characteristics, biological degradability and THMFP(trihalomethane formation potential) of the samples were analysed based on the AMWD(apparent molecular weight distribution). Large portion of dissolved organic carbon(DOC) in the river and lake samples was comprised of LMW(low molecular weight), while that of AHA and WHA was HMW(high molecular weight). The DOC of the lake was evenly distributed in the all range of molecular weight. The river, lake and secondary treated effluent have lower ultraviolet(UV) absorbance at 254nm, and have a higher amount of humic acids. Higher absorbance of humic acids means that aliphatic bond and benzenoid type components that absorb UV light were contained in these kind of humic acids. It was expected that lake sample was the most biodegradable in the different samples investigated, and in order of secondary sewage treatment effluent, river, WHA and AHA based on the result of determination of specific ultraviolet absorbance(SUVA). Biodegradability showed similar result except for ABA, while dissolved organics in the range of LMW decreased during the biodegradability test, and on the contrary those of HMW increased. Production of the SMPs(soluble microbial products) was observed during humicification of dissolved organics and the SMPs were in the range of 0.7∼5.5% of DOC which was the lowest value. Sample had a higher portion of HMW showed a higher production of the SMPs. THM formation was high in the samples containing HMW and similar tendency was shown in the THMFP(trihalomethane formation potential), except for WHA.

자동화학분석기 Cobas Integra를 이용한 화학검사측정에 대한 평가

이용화,정규영,박은주,김종원 대한임상병리학회 1997 대한임상병리학회지 Vol.17 No.5

부순모래를 사용한 강섬유보강 콘크리트의 물성에 관한 실험적 연구

崔榮和,金鍾寅,李明鎭 대구대학교 과학기술연구소 1999 科學技術硏究 Vol.6 No.2

The object of this experimental study is the comparison between the properties of the Steel Fiber Reinforced Concrete(SFRC) using crushed sand and those of SFRC using river sand. In the mix proportion, W/C is 50%, of 0, 0.5, 1.0, 1.5 and 2.0% steel fiber content, the conclusions of the flesh and hardened concrete properties are as follows, 1. The slump loss of SFRC with the passage of time was higher with the increase of fiber content, and the slump loss of crushed sand concrete was a little lower than that of river sand concrete. 2. With increasing of fiber content, the compressive strength of both SFRC using river sand and SFRC using crushed sand increased 10 to 24% compared with that of each plain concrete, and the maximum compressive strength was shown at the 1.5% fiber content. 3. The tensile strength of SFRC using crushed sand was higher than that of SFRC using river sand, and the tensile strength increased remarkably with increasing of fiber content. 4. The flexural strength and the flexural toughness of SFRC using crushed sand were higher than those of SFRC using river sand, and the flexural strength and toughness increased remarkably with increasing of fiber content.

장기재령에 따른 고로슬래그를 사용한 모르타르의 강도특성

최영화,김종인,김태형 대구대학교 과학기술연구소 1998 科學技術硏究 Vol.5 No.4

The purpose of this study is to examine strength characteristics of mortar using blast-furnace slag for long ages, 365days. In this paper, the mortar replaced by varying fineness and content of blast-fumace slag was investigated through the flow value and the compressive strength. This experimental study was acquired following results by the material tests of fresh and hardened mortar proportioned standard sand and natural sand, mixing proportion of 1:2, 1:3, 1:5, slag fineness of 4500, 5500, 6500㎠/g, water binder ratio 40, 45, 50, 55, 60% and replacement rate of 0, 15, 30, 45%. The results are as follows 1. Blast-furnace slag increased somewhat higher flow value. 2. The higher fineness of slag developed the higher compressive strength. 3. The highest compressive strength appeared at 30% replacement rate. 4. Slightly higher compressive strength appeared at standard sand mortar rather than at river sand mortar.

인플레이션 期待下의 貨弊需要

李鐘和,孫東辰 湖西大學校工業技術硏究所 1985 工業技術硏究所論文集 Vol.4 No.-

Milton Friedman argued that physical goods should be regarded as a substitute for money and that higher expected rates of inflation should induce a portfolio shift from money to physical assets. As Friedman has derived his equation, the demand for real balances is a function of the expected rate of inflation in addition to nominal interest rates and real income. A number of empirical studies for different countries have shown that the anticipated rate of inflation has an independent direct effect on the demand for money, other than via interest rates. But in Korea, there are few studies about the role of expected rate of inflation in the demand for money. The purpose of this paper is to test the significance of the sorted-out independent effect of the expected rate of inflation on real balances and to suggest more appropriate monetary policy in such country suffering high inflation as Korea. In this paper a real partial adjustment mechanism of money demand is assumed. And the expected rate of inflation is estimated by the stochastic time series model(ARIMA model). According to the evidence of this paper, the expected rate of inflation exerts significant influences upon money holdings, while nominal rate fo interest has little explanatory power in money demand function. This confirms the fact that nominal rate of interest has been under the strict government control and has not reflected the opportunity cost of money holdings in Korea. These results suggest that monetary authority should control money supply more carefully in Korea, where everyone has inflationary expectations. In further studies particular emphasis should be given on the mechanism of price expectations formation associated with the appropriate specification of the money demand function and the correct forecast of the effect of monetary policy.

호소 저질층의 총질소 및 총인 함량분석에 있어 Microwave와 Autoclave 분해법 비교

박종안,장봉기,민준호,이종화 순천향대학교 기초과학연구소 1999 순천향자연과학연구 논문집 Vol.5 No.1

In order to search an efficient analytical method for analyzing the contents of nutrient salts [total nitrogen(T-N) and total phosphorus(T-P)] in sediments of reservoir, we compared microwave digestion method with autoclave method in sample preparation. The content of T-N obtained by microwave digestion method was lower(approximately 30%) than that obtained by autoclave method. But the content of T-P obtained by microwave digestion method was twice as much as that obtained by autoclave method. The desorption efficiency of T-N and T-P in both methods were good. The reproducibility of measurement results in microwave digestion method was better than that in autoclave method. A considerable amount of both nutrient salts was adsorpted on the sediment of Song-ak reservoir. Depending on the depth of sediment, differences in the contents of T-N were significant. The content of T-N in surface layer was highest. From these results, we recommend the microwave digestion method in sample preparation for analysis of T-N and T-P, because that method shows a higher reproducibility and provides a condition in which both nutrient salts can be simultaneously analyzed. We also suggest that in order to control water quality of reservoir a proper control measurement for nutrient salts adsorpted on sediments was needed.

고로슬래그를 사용한 고강도 부순모래 콘크리트의 물성에 관한 실험적 연구(I) : 아직 굳지않은 콘크리트의 물성

金鍾寅,尹仁茂,崔榮和 大邱大學校 科學技術硏究所 1999 科學技術硏究 Vol.6 No.2

The purpose of this study is to analyse the properties of fresh high strength concrete in conditions of water binder ratios of 25, 30, 35% and blast-furnace slag substitutions of 0, 15, 30, 45%. Additionally, in case of water binder ratio of 30%, the maximum size of coarse aggregate is two kinds of 13, 19 mm. The conclusions of this study are as follows ; 1. The loss of slump and slump flow of concrete increased according to higher blast-furnace slag substitution and smaller coarse aggregate. 2. The loss of air content increased according to lower water binder ratio and higher blast-furnace slag substitution. 3. The unit weight increased according to higher blast-furnace slag substitution and smaller coarse aggregate. 4. The relation of air content and unit weight was inverse proportion, and the unit weight reduced 17kg/㎠ according to increasing of 1% air content.

수생식물의 중금속 흡수능에 관한 연구

이종화,함용규,박종안 한국환경독성학회 1996 환경독성보건학회지 Vol.11 No.2

In this study, we investgated the uptake capacity of several water plants for heavy metals (lead and cadmium) in soil of rivers where are adjacent to a industrial complex in Chun-An city and in A-San city. We also examined the deposition pattern of heavy metal in plants. The results are as follows: 1. The soil of river in Chun-An city was polluted more serious than that of A-San city. In Chun-An city, mean values of lead and cadmium contents in soil were 26.224±28.037㎍/g, and 0.854±1.127㎍/g, respectively. 2. Water plants examined in this study were Sium suave KITAGAWA, Persicaria thunbergii H. GROSS, Phragmites japonica STEUD, Echinochloa crus-galli var. frumentacea WIGHT and Persicaria hydropiper SPACH. Both metal contents of several water plants distributed in Chun-An city were higher than those in A-San city. In these plants, Sium suave showed the highest uptake capacity for lead and cadmium. The mean values of lead and cadmium contents in Sium suave were 40.957 ±29.577 ㎍/g and 1.930±1.076 ㎍/g, respectively. Persicaria thunbergii also showed a relatively high uptake capacity for both metal. 3. Correlation between metal contents in soil and water plants was high. In both cases of Sium suave and Persicaria thunbergii correlation coefficients were 0.605 and 0.549, respectively. 4. We analyzed lead and cadmium contents in root, stem and leaf of several water plants. Both metals were mostly deposited in root. Much of both metals were also deposited in leaf. From the results, we suggest that Sium suave KITAGAWA and Persicaria thunbergii H. GROSS can be used to reduce heavy metals from industrial waste water.