새로운 연노출의 효과지표로서의 혈장 δ-aminolevulinic acid 측정의 유용성

이금원,황보영,김용배,리갑수,이성수,장봉기,함정오,안규동,이병국 순천향대학교 산업의학연구소 2001 순천향산업의학 Vol.7 No.1

To evaluate the usefulness of the measurement of plasma δ - aminolevulinic acid (ALAP) as a new effect indicator of lead exposure, the association of ALAP with blood lead, DMSA chelatable lead and bone lead with a special emphasis of genetic interaction of ALAD polymorphism was studied with 419 lead exposed workers and 85 non-lead exposed workers. Lead workers were recruited from storage battery industries, secondary smelting industries and other lead using industries and non-lead workers selected from electronic refrigerator manufacturing industry. Blood lead, DMSA chelatable lead and bone lead were chosen for parameters of lead exposure. Plasma and urinary ALA were selected for the effect parameter of lead intoxication. Information for age, smoking, drinking habit and body mass index were also obtained. Job duration for lead workers was also collected. The overall prevalence of the variant allele, ALAD type 1-2 or 2-2(ALAD2) in lead exposed workers was 10.0% (42 out of 419 lead workers) which was not differed from control workers (9.4% : 8 out of 85). The means blood lead and DMSA chelatable lead of lead workers with ALAD 1(ALAD type 1-1) were lower than those of lead workers with ALAD2, but the differences were not statistically significant. On the other hand, the mean of tibia lead of lead workers with ALADI was higher than that of lead workers with ALAD2, but the difference was not statistically significant. DMSA chelatable lead showed highest correlation with log transformed plasma ALA(LALAP)(r=0.682) and blood lead and tibia lead had r=0.650, r=0,402 correlation coefficient with LALAP respectively On the other hand. log transformed urinary ALA(LALAU) had lower correlation coefficient with all three parameters of lead exposure than LALAP. The equation of robustic simple linear regression of blood lead on LALAP was LALAP=2.0439+0.0165PbB in ALADI lead workers and LALAP=2.031+0.0121PbB in ALAD2 lead workers. ALAD genotype in the multiple regression analysis of blood lead with LALAP after adjusting for possible confounders(sex, ago, BMI, smoking and drinking status and job duration) showed significant main effect on LALAP resulting lower LALAP in ALAD2 lead workers than ALADI lead workers. On the other hand, effect modification of ALAD genotype was observed in the multiple regression analysis of tibia lead with LALAP after adjusting for possible confounders, but there was no significant effect of ALAD genotype in the multiple regression analysis of DMSA chelatable lead with LALAP after covariate adjustment. With above results, plasma ALA was found to be a useful effect parameter of lead exposure compared with urinary ALA. It was also observed that ALAD polymorphism made significant effect on the association of blood and tibia lead with ALAP. Thc lower plasma ALA in ALAD2 lead workers suggested supportive effect of ALAD2 in lead exposure.

형상기억복합재료에 대한 온라인 모니터링 시스템 개발

이동화,박영철,이민래,이동화,이규창 한국비파괴검사학회 2003 한국비파괴검사학회지 Vol.23 No.1

형상기억복합재료를 제조하기 위하여 핫프레스 방법을 이용하여 최적의 제조조건을 도출하였으며 냉간압연에 의해 기지재와 강화재의 계면접합을 강화하여 강도를 증가시켰다. 이러한 방법에 의해 제조된 형상기억복합재료에 대하여 외부 하중에 의한 손상정도와 균열의 발생을 감지하여 균열 발생 및 진전을 억제하는 온라인 모니터링 시스템을 개발하고자 한다. 이를 위하여 음향방출 신호의 파라미터를 이용하여 손상에 따른 최적의 AE 파라미터를 도출하였으며 가열시스템을 이용하여 형상기억합금을 가열함으로써 형상기억합금의 수축에 의한 복합재료 내부에 균열진전을 억제시키는 시스템을 개발하였다. A hot press method was use for the optimal manufacturing condition for a shape memory alloy(SMA) composite. The bonding between the matrix and the reinforcement within the SMA composite by the hot press mothod was strengthened by cold rolling. In this study, the objective was to develop an on-line monitoring system for the prevention of the crack initiation and propagation by shape memory effect of SMA composite. Shape memory effect was used to prevent the SMA composite from cracking. For the system to be developed, an optimal AE parameter should be determined based on the degree of damage and crack initiation. When the SMA composite was heated by the plate heater attached at the composite, the propagating cracks appeared to be controlled by the compressive force of SMA.

연작업자들의 신기능 평가에서 요중 δ-aminolevulinic acid 측정의 의의

이병국,이숙,김용배,리갑수,김화성,황규윤,장봉기,이성수,안규동 순천향대학교 산업의학연구소 1999 순천향산업의학 Vol.5 No.1

To clarify the effect of occupational lead exposure on renal function 241 lead workers working and 56 non lead workers were studied in 5 lead acid battery industries. Study variables for renal effect were urinary N-acetyl-β-D-glucosaminidase(NAG), urinary total protein(U-TP), blood urea nitrogen(BUN), serum creatinine(S-Cr), and serum uric acid(S-Ua). On the other hand, blood lead(PbB), zinc protoporphyrin in whole blood(ZPP), and delta-aminolevulinic acid in urine(δ-ALA) were selected for the variables of lead exposure. Information on age, work duration, smoking and drinking history were also obtained. The results obtained were as follows. While the mean values of lead exposure indicators of lead workers were significantly different from non-exposed ones, the mean values of BUN, U-TP and S-Cr of renal function indicators of exposed were also different from non-exposed. BUN, U-TP and NAG showed statistically significant correlation with PbB and ZPP, and NAG revealed also statistically strongly significant correlation with δ-ALA. On multiple regression using renal fuction indicators as a dependent variable and δ-ALA, age, work duration,lead exposure,smoking and drinking as independent variables, only δ-ALA contributed to NAG.

사면의 안정도 해석을 위한 입체투영법

이성대,이철우,이동우,이성규 公州大學校 基礎科學硏究所 1996 自然科學硏究 Vol.5 No.-

암반 사면의 안정성을 해석하는데 입체투영기법을 이용하였다. 안정도에 영향을 미치는 요인으로는 절리의 경사, 암석의 밀도, 내부마찰각등이 있으나, 가장 중요한 요인은 절리면의 경사이다. 이 연구에서는 암석의 점착력은 무시하고 단지 내부마찰각과 절리의 주향 및 경사만을 이용하였다. 그 결과 입체투영도에서 나타나는 암반사면의 안정도는 이동력과 저항력의 상대적인 크기에 의하여 좌우되는 것으로 나타났다. 동시에, 지반진동에 의한 영향도 입체 투영기법으로 찾아낼수 있다는 것이 밝혀졌다. Stereographic projection technique was used to analyze rock slope stability. Strike and dip of joints, rock strength, and internal frictional angle are major factor on slope stability. Among them, the most important factor is strike and dip of joints. In stereographgic projection technique, only internal frictional angle, and strike and dip of joints were used to interprete slope stability. Cohesion of rock was not considered. It is suggested that the rock slope stability on stereographic projection depends upon only the differential stress between driving and resisting force. At the same time, Stereographic projection technique on seismic loading was proposed in this study.

업종에 따른 연 취급 사업장의 기중 연 농도 및 연 노출 수준 평가

이병국,김용배,리갑수,안현철,김화성,이용진,황규윤,장봉기,이성수,안규동 순천향대학교 산업의학연구소 1999 순천향산업의학 Vol.5 No.1

In order to obtain an useful information for health management and biological monitoring of lead exposed workers, Authors tried to investigate air lead level and the lead exposed level of workers in lead industry according to occupational category. The subjects in our study were 2074 workers in 7 lead-using industries, and study subjects were divided into 4 occupational categories such as storage battery industry (type 1), primary smelting industry (type 2), secondary smelting industry (type 3) and litharge making industry (type 4). Blood zincprotoporphyrin concentration (ZPP), blood lead concentration (PbB) and urinary δ -aminolevulinic acid (ALAU), hemoglobin (Hb), hematocrit (Hct) were selected as the indices of lead exposure. Personal variables such as age, work duration were also collected. The results were as follows. 1. The geometric mean air lead in 9 lead-using industry was 0.1133±4.3120 ㎎/㎥, and that in type 1, 2, 3 and 4 was 0.1038±3.4952 ㎎/㎥, 0.0429±3.4329 ㎎/㎥, 0.1877±2.5123 ㎎/㎥ and 0.9961±5.2910 ㎎/㎥, respectively. 2. The mean ZPP in 9 lead-using industry was 53.1±28.0 ㎍/㎗, and that in type 1, 2, 3 and 4 was 52.0±24.8 ㎍/㎗, 48.0±16.4 ㎍/㎗, 109.8±85.6 ㎍/㎗ and 74.3±37.8 ㎍/㎗, respectively. There was significant difference in ZPP according to occupational category (P<0.01). The percents of lead workers whose ZPP were above 100 ㎍/㎗ in type 1, 2, 3 and 4 were 4.0%, 1.7%, 34.3% and 21.6%, respectively. 3. The mean PbB in lead-using industry was 26.0±11.2 ㎍/㎗, and that in type 1, 2, 3 and 4 was 25.3±11.1 ㎍/㎗, 26.7±8.8 ㎍/㎗, 50.3±15.2 ㎍/㎗ and 36.4±11.0 ㎍/㎗, respectively. There was significant difference in PbB according to occupational category (P<0.01). The percents of lead workers whose PbB were above 40 ㎍/㎗ in type 1, 2, 3 and 4 were 10.4%, 7.7% 71.9% and 43.2%, respectively. 4. While the correlation of Hb corrected PbB with ZPP was higher than non corrected PbB, the correlation of log-transformed ZPP with PbB was higher than non corrected ZPP. 5. Simple linear regressions of PbB and corrected PbB as independent variable with ZPP, log-transformed ZPP and ALAU as dependent variable were statistically significant (P0.01). Coefficient of determination of corrected PbB with other variables was higher than non corrected PbB. As the result of this study, it was suggested that reconsideration of environmental and biological monitoring program was highly recommended for secondary smelting and litharge making industry.

무보수 호흡용 보호구 착용이 2차 제련 연작업자들의 연폭로지표에 미치는 영향

이영구,황보영,리갑수,이성수,안규동,이병국 순천향대학교 산업의학연구소 1997 순천향산업의학 Vol.3 No.1

It is often impossible to improve working condition in small scaled lead industries due to inherent old work process and lack of capital to improve it. This is particularly true in secondary smelting industries in Korea. Alternative ways to protect workers in these industries are respiratory protection and job shift if at all possible to less harmful workplace. This study intended to evaluate the effect of maintenance free respirator and job shift of lead workers to other non-lead workplace on the level of lead exposure of workers in terms of blood zinc protoporphyrin as an index of lead absorption and intoxication of lead workers. Seventy three workers of one secondary smelting industry whose work duration was more than 4 months were studied. All workers were classified into 4 groups such as managemental workers(8), non-lead workers(14), lead workers(44) and shift workers(7). Personal data such as age and work duration were collected and air concentration of lead in each workplace were also measured. Blood ZPP was chosen as an index of biological monitoring and was measured regularly once a month for 5 months study period. The results obtained were as follows: 1. There were no significant differences of mean blood ZPP during 5 months study period in management workers and non-lead workers showing the range of 23.1-26.5 ㎍/100ml and 22.2-24.2 ㎍/100ml respectively. 2. Rapid reduction of mean blood ZPP from first month (203.0 ± 106.7 ㎍/ 100ml) to third month (128.4 ± 75.1 ㎍/100ml) was noticed and after 3 months period there was no further reduction of blood ZPP in lead workers. 3. The initial mean blood ZPP of shift workers who moved to non-lead workplace was 394.3 ± 114.9 ㎍/100ml and their mean blood ZPP were steadily decreased every month from 344.3 ± 98.4 ㎍/100ml of first month to129.9 ± 33.5 ㎍/100ml of 4th month). 4. The average reduction rate of blood ZPP based on initial blood ZPP was 37.0% in lead workers for 3 months period and 67.1% in shift workers for 4 months period. With above results it was observed that respiratory protection and work shift could protect lead workers from lead exposure by reducing lead exposure in secondary smelting industry which had fairly bad working condition. But for a complete prevention of lead poisoning, it has certain limitation and should be used as an interim method until fundamental engineering control of workplace.

전자부품 제조업 근로자들의 시력변화에 대한 연구

이용만,안규동,이성수,함정오,김화성,리갑수,이병국 순천향의학연구소 1996 Journal of Soonchunhyang Medical Science Vol.2 No.2

근접작업이 시력약화의 원인이 될 수 있는가를 알아보기 위하여 전자부품을 제조하는 2개 사업장에서 1991년에서 1993년까지 입사한 근로자들 중에서 근접작업으로 인정되는 마이크로칩을 조립하는 근접작업자 306명을 조사군으로, 대조군은 세탁기 타이머 및 일반 기계기구를 조립하는 작업자 154명, 계 460명을 선정하였다. 이들 대상자는 1991년 입사자는 1993, 1994, 1995년 시력을 조사하였으며, 1992년 입사자는 1993, 1994, 1995년 3년동안 조사를 하였으며, 1993년 입사자는 1994, 1995년 2년간 시력을 조사하였다. 대상자 중에서 입사시 안경을 착용한 근로자는 82명(17.8%)이었다. 따라서 남자 근로자와 안경착용자를 제외한 여성 근로자들 335명만을 추적 조사하여 다음과 같은 결론을 얻었다. 조사군에서 입사시 시력 1.0 이상이었던 근로자의 분포는 취업 1년 후 약 25-35% 정도 감소하였으며, 2년후에는 약 40-60% 정도의 감소를 나타내었고, 3년 후 약 50-65% 정도로 감소하였고 4년후에는 약 65% 이상 감소하였다. 그러나 대조군에서는 1.0 이상의 시력을 보였던 근로자들의 비율이 취업 1년 또는 2년 후 15-30%의 감소를 보이고 있으나 그 이후에는 큰 변동이 없었다. 이들의 시력변화를 근무년수에 따라 알아보기 위하여 조사된 시력을 순위변수로 하여 Kruskall-Wallis 검정을 시행한 결과 조사군, 대조군 모두에서 근속년수에 따른 순위의 합의 평균이 년차적으로 유의하게 감소하였으나, 입사시부터 근속년수에 따른 조사군과 대조군과의 순위합의 평균에 의한 시력차 비교에서 입사시 조사군의 순위합의 평균이 유의하게 높았던 것이 근무기간에 따라 대조군의 평균이 높아지면서 통계적 유의성이 없고 대체적으로 1년 이후부터 변화가 적은 것으로 나타나 근접작업으로 인한 시력약화를 추정할 수 있었다. This study was carried out to investigate that the close distance works were associated with decreased visual acuity. 306 workers were subjects who had been recruited from 1991 to 1993 in two electronic parts manufacturing factories, and 154 workers were controls who had been employed from 1991 to 1993 in launder machine timer and general machine assembly factories. Subjects who had been employed in 1991 and 1992 were follow up from 1993 to 1995, and subjects who had been employed in 1993 were from 1994 to 1995. The male workers as well as glasses wearing workers were excluded. Only 335 female workers were followed up to study the change of visual acuity. The results were as follows; The rate of workers with visual acuity over 1.0 at recruit year in subjects group was decreased about 25-35% after 1 year, 40-60% after 2 years, 50-65% after 3 years, and 65% after 4 years. While, the rate of workers with visual acuity over 1.0 at recruit year in control group was decreased about 15-30% after 1 or 2 years, and there was no more additional visual acuity reduction after then. Kruskall-Wallis test was performed to investigate the change of visual acuity in subject and control group by work duration. The means scores of ranks in both group were significantly decreased by work duration. The mean scores of ranks in subject group at recruit year were significantly higher than those in control group at recruit year, but these differences were disappeared after 1 year work. Therefore, this suggest that close distance workers may be affected their visual acuity.

연폭로 근로자들에서 흡연 및 보건행태학적 변수가 주관적 자각증상에 미치는 영향

이성수,김화성,리갑수,안규동,이병국 순천향대학교 산업의학연구소 1997 순천향산업의학 Vol.3 No.1

To investigate the effect of smoking and drinking habit on the health status of lead workers, 220 male workers in lead using industries and 210 male controls were selected for this study. Selected study variables were lead in blood (PbB), zinc protoporphyrin in blood (ZPP), delta-aminolevulinic acid in urine(DALA), hemoglobin (Hb), and hematocrit (Hct). Questionnaire for lead related symptoms (15 symptoms) and smoking and drinking habit was provided to all the workers and filled up by themselves and reconfirmed by physician. The results obtained were as follows; 1. While smoking and drinking rate of lead exposed group were 77.7% and 75.8%, respectively, those of control group were 53.3% and 35.7%, respectively. 2. Mean values of lead exposed indices of lead workers was significantly different from other group. 3. In exposed workers, there was significant differences of DALA between smoker and non-smoker. 4. The neuromuscular symptom prevalence of lead exposure was higher in lead exposed group than non-exposed group. 5. Symptom prealence of lead exposure were higher in drinking and smoking group than non-drinking and non-smoking group. 6. While logistic analysis of positive neuromuscular symptom with categorized blood lead and age, smoking, drinking as categorized independent variables indicated that only blood lead (>40㎍/㎗) was significantly contributed to dependent variable with 95% significant odd ratio confidence interval, logistic analysis of positive constitutional symptom with same categorized independent variables indicated that only age (>40years) was significantly contributed to dependent variable. And logistic analysis of total symptom with same categorized independent variables indicated that blood lead (>40㎍/㎗) and age (>40years) were significantly contributed to dependent variable.

납 폭로 근로자에서 δ-aminolevulinic acid dehydratase 유전형질이 zinc protoporphyrin 및 δ-aminolevulinic acid에 미치는 영향

이병국,황규윤,장봉기,김용배,리갑수,안현철,김화성,이성수,안규동,박종범 순천향대학교 산업의학연구소 1999 순천향산업의학 Vol.5 No.1

The inhibition of δ-aminolevulinic acid dehydratase (ALAD) in the heme synthetic pathway results in increased protophoryphyrin (ZPP) and δ-aminolevulinic acid (ALA) and is responsible for some of toxicological effects of lead. This enzyme is coded by the ALAD gene containing 2 co-dominant alleles. The polymorphisms of ALAD gene may be related to differential effects of lead on ZPP and ALA, ALAD genotype was measured in 975 Korean male lead workers, of whom 897 were homozygous for ALAD1 (ALAD 1-1 genotype) and 96 were heterozygous for ALAD2 (ALAD 1-2 genotype). Blood lead in subjects with ALAD1 was significantly higher than those with ALAD2 (p = 0.01). No difference between ALAD genotypes was found for age, exposure duration, ZPP, ALA, hemoglobin, hematocrit, body mass index, tobacco and alcohol use. After adjustment for possible confounders, ALA and ZPP became significantly elevated in ALAD1 subjects (p = 0.004 and 0.055, respectively). This result suggests that ALAD1 subjects may be more susceptible to the hematotoxicologic effects of lead than ALAD2 subjects.

로케트 工學에 관한 硏究 : 第1報 : 亞音速 亂流流動에서 飛行翼模型의 剝離現象 Ⅰst Report : Separation of Airfoils in Subsonic Turbulent Flow

朴煥奎,金鍾一,金鎭興,李茂錫,朴吉文,鄭洛奎,李行男,李東起 조선대학교 동력자원연구소 1984 動力資源硏究所誌 Vol.6 No.2

Separation, pressure and velocity distributions were studied fully developed two dimensinonal, incompressible flow over a flat airfoil in subsonic wind tunnel. Velocity and turbulence were measured with a two channel constant temperature hot wire anemometer and pressure with a pitot tube and pressure tranducer system. The experimental results were obtained as follow: (1) Turbulent intensity of shear layer just outside the separation point is considered to affect the size of separation bubble. (2) Static pressure coefficient is separated into three regions according to its value change. (3) Separation point is varied with the change of attack angle. (4) Velocity distributions and boundary layers normal to airfoil surface are changed as variation of attack angle of airfoil.