톨루엔을 포함한 유기용제의 직업적 폭로로 인한 신경내분비계 영향

이채언,이종태,정의화,손혜숙,문덕환,전진호,강정학,이창희,김휘동,김종한,정귀옥 大韓産業醫學會 1995 대한직업환경의학회지 Vol.7 No.2

Long term occupational exposure to solvent mixtures may cause adverse effects to the central nervous system with neurobehavioral symptoms. And some organic slovents have been suggested to cause impairment of tuberoinfundibular dopaminergic activity and neurochemical mechanisms controlling pituitary secretion. For the purpose of assessing neuroendocrine effects in occupational solvents exposure, hormonal study settings (shoes-manufacturing industry & fishing products industry) and compared with nonexposed controls(33 men, 85 women). Male workers exposed to solvent mixtures had significantly lower plasma level of follicle-stimulating hormone(FSH) than nonexposed male controls. While female workers exposed to solvent mixtures had significantly lower plasma levels of growth hormone(GH), and thyroid-stimulating hormone(TSH) than nonexposed female controls. The results of significant decrease in plasma concentrations of pituitary hormones(FSH, GH, and TSH) in workers exposed solvent mixtures indicate that occupational exposure to solvent mixtures may induce neuroendocrine effects through an effect on hypothalamic pituitary axis.

驅動部 動特性을 高慮한 可變構造 制御 알고리듬

강익호,김정욱,신휘범,이정훈,고상호 慶尙大學校生産技術硏究所 1997 生産技術硏究所論文集 Vol.13 No.-

In this paper, the dynamics of actuators for generating the input of plants is considered in a design of the variable structure systems. While the input for plants is usually implemented by means of a certain actuator, the actuator dynamics is not incorporated in most of the VSS researches until now. The control algorithm of a VSS incorporating actuator dynamics is presented. and the simulation is given the usefulness of the algorithms.

유기용제 폭로가 여성 근로자들의 월경에 미치는 영향

김대환,이채관,김휘동,강동묵,문덕환,김정호,손병철,이창희,이채언 인제대학교 백병원 2002 仁濟醫學 Vol.23 No.1

유기용제는 산업장에서 널리 사용되고 있다. 특히 여성근로자들의 폭로기회가 증가하고 있으며 이로 인한 자연유산, 수태능력 감소, 월경이상 등이 보고되고 있다. 따라서 유기용제 폭로가 여성근로자들의 월경에 미치는 영향을 보기 위해 설문조사와 월경주기별 여성생식 호르몬(progesterone, estrogen) 분석을 하였다. 그 결과 폭로군에서 progeterone의 억제효과가 유기용제에 폭로되는 여성근로자들의 다양한 월경이상을 초래할 가능성이 있는 것으로 생각된다. ■ Objectives This study was conducted to evaluate the effects of menstrual function in female workers exposed to organic solvents. ■ Methods Rates of menstrual disorders were studied in 87 female workers with exposure to organic solvents(Cn/Hn-value 0.713) in a factory manufacturing shoes and compared with 83 general female workers who had no exposure to organic solvents, Detailed menstrual and reproductive histories were obtained by personal interview using structured questionnaire, and plasma concentrations of progesterone and estrogen were assayed by radioimmunoassay(RIA). ■ Results The rates for menstrual irregularity, menstrual duration, blood clot in menstrual flow and dysmenorrhea were not significantly different in both groups. Number of using menstrual pad was significantly higher and the plasma level of progesterone during 6-11th day of menstrual cycle was significantly lower in the exposed group compared with non-exposed group(P<0.05). ■ Conclusions It seemed to be suppression effect of organic solvents on the reproductive hormones(progesterone and estrogen) in female workers. But there was no evidence that menstrual disorder was likely to result from exposure to organic solvents, because other behavioral, psychological and work related factors may also affect menstrual function.

외상환자에서 전신성 염증 반응 증후군 (Systemic Inflammatory Response Syndrome)의 발생과 혈청 TNF-α와의 관계

김현,이강현,임종천,조준휘,오범진,황성오 大韓應急醫學會 1998 대한응급의학회지 Vol.9 No.4

Background and purpose: The systemic inflammatory response syndrome(SIRS), as defined recently by critical-care specialists, may result from various etiologies including infection, burn, or trauma. The purpose of this study was to determine whether TNF-αis associated with the development of systemic inflammatory response syndrome caused by multiple trauma. Methods: The study population consisted of 21 patients with multiple trauma presented emergency department within 2 hours after insult were enrolled in this study. Multiple blood samples were serially drawn to measure serum TNF-αlevel on admission, 12 hours, 24 hours, and every day until 5 days after injury. Serum TNF-αwas measured by ELISA ("Sandwich type"). Blood samples of fifteen volunteers were used as a reference value for serum TNF-α. Results: Serum TNF-αlevels of SIRS group were persistently elevated above reference value until 3 days after on admission. Peak serum TNF-αlevel at 12 hours after admission was higher in SIRS group than non-SIRS group(p<0.05). There was no significant correlation between injury severity score and TNF-αlevels on regression analysis, all patients with ISS higher than 16 had SIRS. No one had SIRS among patients with ISS less than 16. Conclusion: The result of this study suggests that persistent elevation of TNF-αand degree of injury severity are associated with the development of systemic inflammatory response syndrome in multiple trauma.

심초음파로 결정된 응급 심낭천자술의 천자부위

김성환,황성오,이강현,조준휘,강구현,문중범,이승환,윤정한,최경훈,김영식 대한응급의학회 2000 대한응급의학회지 Vol.11 No.3

Background: The aim of this study was to determine whether the conventional subcostal approach is suitable for emergency pericardiocentesis in patients with cardiac tamponade or impending cardiac tamponade. Methods: This study was a prospective, observational study conducted at the emergency department of a tertiary hospital, Patients who had symptomatic pericardial effusion and who needed emergency pericardiocentesis in the emergency department were included in this study. We measured the epicardium-to-pericardium distance at the subcostal, parasternal, and apical area with two-dimensional echocardiography to determine the appropriate puncture site for pericardiocentesis. An epicardium-to-pericardium distance of more than 1.0 cm was considered as the primary safety factor in determining the Puncture site for pericardiocentesis. The skin-to-pericardium distance was considered as secondary safety factor. Results: Ninety-five consecutive patients(55 males and 40 females; total mean age: 53 year old) with cardiac tamponade or impending cardiac tamponade were enrolled in this study. The puncture site for pericardiocentesis, as determined by echocardiography, was the subcostal area in 43 patients(45%), the apical area in 40 patients(42%), the left parasternal area In 11 patients(12%), and the right parastemal area in one patient(1%). Pericardiocentesis failed in 2 patients(2%) with the subcostal approach and in one patient(1%) with the apical approach. The average epicardium-to-pericardium distance was 31 ±21 mm in patients with the subcostal approach and 21±8 mm in patients with other approaches. There were no differences in the amount of pericardial fluid and in the intraperical pressure among patient groups according to puncture site. There were two procedure related complications: a puncture of the right ventricle with the subcostal approach and a ventricular tachycardia with the apical approach.

이중혈류유발 심폐소생술이 심정지를 유발한 개의 단기 생존율에 미치는 영향

황성오,조준휘,강구현,김성환,문중범,이강현,이승환,윤정한,최경훈,홍은석 대한응급의학회 2000 대한응급의학회지 Vol.11 No.3

Background and Objectives: We previously reported that, compared with standard cardiopulmonary resuscitation(S-CPR), better hemodynamic effects could be achieved by simultaneous sterno-thoracic cardiopulmonary resuscitation(SST-CPR) in which we compressed the sternum and constricted the thorax circumferentially during the systolic period by using a device. This study was designed to assess whether SST-CPR, compared with S-CPR, improve the survival rate of dogs with cardiac arrest. Subjects and methods: Twenty-five mongrel dogs(19∼31㎏) were enrolled in this study. After four minutes of ventricular fibrillation induced by an AC current, animals were randomized to resuscitate with either S-CPR(n=13) or SST-CPR(n=12). Epinephrine(1 ㎎) was injected into the right atrium every three minutes after the beginning of CPR. Defibrillation was attempted after 6 minutes of CPR. Standard advanced cardiac life support was started if defibrillation was not successful. Results: SST-CPR resulted in significantly(p<0.001) higher systolic arterial pressure(91±47 vs 47±24 ㎜ Hg), diastolic pressure(43±24 vs 17±10 ㎜ Hg), coronary perfusion pressure(35±25 vs 13±9㎜ Hg), and end tidal CO2 tension(9±4 vs 3±2 ㎜ Hg). Two of 13 animals(15 %) resuscitated with S-CPR and six of 12 animals(50%) resuscitated with SST-CPR survived until 12 hours after cardiac arrest(p<0.05). Donclusion: SST-CPR, compared with S-CPR, improves the short-term survival rate in canine cardiac arrest.

두가지 혈류 유발방법에 의한 새로운 심폐소생술(이중 혈류 유발 심폐소생술)장치의 개발

황성오,김현,조준휘,오범진,임종천,최경훈,윤정한,이승환,김영식,이강현,이윤선 大韓應急醫學會 1999 대한응급의학회지 Vol.10 No.2

Background: There have been many efforts to augment blood flow during cardiopulmonary resuscitation. These efforts have focused on maximizing the effect of cardiac pump or thoracic pump alone. However, considering that the heart is the biggest blood reservoir and increase of intrathoracic pressure can generate blood flow, simultaneous exploitation of both mechanisms may have synergistic effect. We hypothesized that simultaneous chest constriction in addition to sternal compression by standard CPR may have additive hemodynamic effects by preventing deformation of the chest and increase of intrathoracic pressure. Methods and results: we built a new mechanical device to perform compression and thoracic constriction simultaneously. The device consists of two main elements. Piston in the center is to depress the sternum. Strap is to constrict the thorax circumferentially. Strap is attached to both sides of the piston. When the piston is pushed down, it depresses the sternum and pulls on the thoracic strap. To determine strap width to produce optimal hemodynamic effect, we measured hemodynamic parameters with variable widths of strap in two dogs after induction of ventricular fibrillation. Result of the experiment showed that 10cm wide strap was determined to be most effective. We also determined optimal depth of compression to produce maximal hemodynamic effect with animal experiments using two dogs. Animal experiments showed that the highest aortic pressure could be generated when the stemum was depressed to 5 cm. Cardiopulmonary resusciation using a new device could generate higher systolic aortic pressure, coronary perfusion pressure and end-tidal carbon dioxide tension in comparison with standard cardiopulmonary resuscitation in a pilot animal study using two dogs. Conclusion: New cardiopulmonary resuscitation method using a mechanical device designed by us could perform sternal compression and simultaneous thoracic constriction, and generate better hemodynamic effects than standard cardiopulmonary resuscitation in pilot animal experiments.

부산지역 조선업 협력업체 근로자들의 산업재해 관련요인

신성환,김대환,안진홍,김휘동,김정호,강현만,이종태 大韓産業醫學會 2008 대한직업환경의학회지 Vol.20 No.1

목적: 조선업 협력업체의 재해율 및 재해자 특성을 파악하고,이들의 생활습관요인 및 사회 인구학적 요인을 포함하는 개인적 특성과,작업과 관련된 직업적 특성을 조사하여 산업재해 관련요인을 규명하고자 하였다. 방법: 2007년 5윌부터 7월까지,산업재해예방 안전교육을 실시한 부산지역 64개 조선업 협력 사업장의 생산직 근로자 1, 651명을 대상으로 개인적 특성,직업적 특성,산업재해 특성에 관해 자기기입식으로 설문조사를 실시하였다. 산업재해는 최근 5년 이내에 1회 이상 발생한 경우로 한정하였고,재해로 인한 요양일수에 따라 Group I(요양일수 4일 미만). Group II(요양일수 4일 이상). Group III (Group I+Group II)로 구분하여 재해 경험이 없는 군과 비교하였다. 통계적 유의성이 있는 요인들을 파악한 후 다중 로지스틱 회귀분석을 시행하여 보정된 교차비를 산출하였다. 결과: 본 연구에서의 재해율은 2006년을 기준으로 전체 재해자가 125명, 7.57%, 4일 이상의 요양기간을 필요로 하는 재해자가 75명, 4.30%였다. 산업재해 발생건수는 취부 작업에서 가장 많이 발생하는 것으로 나타났고,산업재해보상보험 처리비율은 4일 이상 요양을 한 재해자 중 30%였다. 산업재해와의 관련성에 있어서 Group I에서는 대졸이상의 교육수준(OR 2.78), 높은 피로도(OR 2.18), Group II에서는 5시간미만의 수면시간(OR 3.47), 높은 피로도(OR 2.79), 주 56시간 이상의 작업시간(OR 1.53), Group III에서는 대졸이상의 교육수준(OR 1.78), 5시간미만의 수면시간(OR 2.98), 내쁜 수면의 질(OR 1. 65), 높은 피로도(OR 2.58)가 통계적 유의성이 있었다. 결론: 조선업 협력업체 근로자들을 대상으로 실시한 본 연구를 통하여 5시간 미만의 수면시간,나쁜 수면의 질,높은 피로도,주 56시간 이상의 작업시간,대졸이상의 교육수준이 산업재해 관련요인으로 밝혀졌다. 따라서 이들 사업장의 산업재해발생과 관련해서 개인적 생활습관, 작업 환경 및 작업 조건을 개선하는 등의 산업 재해 관련요인 관리가 중요할 것으로 판단된다. Objective: This study was conducted to evaluate both personal and work-related factors associated with occupational injuries of ship-building supply workers in Busan, Korea. Methods: A self-administered, questionnaire survey, asking both personal and work-related factors associated with occupational injuries, was administered to 1,651 workers from 64 different ship-building supply companies in Busan, Korea. All occupational injuries had occurred within the previous 5 years. The workers were divided into three sub-groups: Group I, under 4 day-sick leave, Group II, 4 day-sick leave and over, and Group III, which consisted of both Groups I and II. The statistical significance of the factors associated with occupational injuries underwent cross tabulation analysis for each group. Afterwards, the relationships between the factors which had statistical significance and the occurrence of occupational injuries were analyzed through multiple logistic regression by using the SPSS 12.0 K program. Results: The prevalence of occupational injuries was 4.30% in Group II and 7.57% in Group III. The work activities which had the most frequent occupational injuries were 'Fit-up' and 'Welding', and 30.0% of injured workers were covered by workers' compensation in Group II. According to the multiple logistic regression analysis results, the factors which had statistical significance in occupational injury occurrence were education level above college (OR 2.78) and high level of fatigue (OR 2.18) in Group I, sleeping less than 5 hours per day (OR 3.47), high level of fatigue (OR 2.79) and working over 56 hours per week (OR 1.53) in Group II, and education level above college (OR 1.78), sleeping less than 5 hours per day (OR 2.98), poor sleep quality (OR 1.65) and high level of fatigue (OR 2.58) in Group III. Conclusion: This study demonstrated that several factors of ship-building supply workers such as sleep hours, sleep quality, fatigue, working hours, and educational level exerted a statistical effect on the occurrence of occupational injuries, In association with occupational injuries occurrence, these factors need to be controlled by proper methods such as effective safety education, work condition modification, and life style management.

웨어러블 심전도 측정과 임상 심전도 측정과의 상관관계에 대한 연구

이강휘(Kang-Hwi Lee),이성수(Seong-Su Lee),김상민(Sang-Min Kim),이혁재(Hyeok-Jae Lee),민경진(Kyoung-Jin Min),강현규(Hyun-Kyu Kang),이주현(Joo-Hyeon Lee),곽휘권(Hwy-Kuen Kwak),고윤수(Yun-Soo Ko),이정환(Jeong-Whan Lee) 대한전기학회 2018 전기학회논문지 Vol.67 No.12

Recent advances in ICT technology have transformed many of our daily lives and attracted a lot of attention to personal health. Heart beat measurement that reflects cardiac activities has been used in various fields such as exercise evaluation and psychological state evaluation for a long time, but its utilization method is limited due to its differentiation from clinical electrocardiogram. Therefore, in this study, we could observe the change of the measured signal according to the change of the distance and the position of the measuring electrodes which are non-standard electrode configuration. Based on the electric dipole model of the heart, correlation with clinical electrocardiogram could be confirmed by synthesizing multiple surface potentials measured with a shorter electrode distance than standard one. From the electromagnetic point of view, the distance between the measuring electrodes corresponds to the distance that the electric potential by the cardiac electric dipole moves, and the electric potential measured at the body surface is proportional to the moving distance of the electric potential. Therefore, it is preferable to make the distance between electrodes as long as possible, and to position the measuring electrode close to the ventricle rather than the atrium. In addition, it was found that standard electrocardiographic waveforms could be synthesized by using arithmetic sum of multiple measuring electrodes due to the relationship of electrical dipole vectors, which is obtained by dividing and positioning a plurality of measuring electrodes on a reference electrode line, such as Lead-I, Lead-II direction. Also, we obtained a significant Pearson correlation coefficient (r = 0.9113 ± 0.0169) as a result of synthetic experiments on four subjects.

Asymmetric Skin-to-Electrode Impedance Characteristics of Concentric Circular Ring Electrode for Monitoring of Electrical Activity of the Heart

Kang-Hwi Lee,Jeong-Whan Lee,Woo-Chul Jung,Kyeong-Seop Kim,Jae-Hoon Jun,Dong-Jun Kim 제어로봇시스템학회 2006 제어로봇시스템학회 국제학술대회 논문집 Vol.2006 No.10