한국인 직무 스트레스 측정도구의 개발 및 표준화

장세진,고상백,강동묵,김성아,강명근,이철갑,정진주,조정진,손미아,채창호,김정원,김정일,김형수,노상철,박재범,우종민,김수영,김정연,하미나,박정선,이경용,김형렬,공정옥,김인아,김정수,박준호,현숙정,손동국 大韓産業醫學會 2005 대한직업환경의학회지 Vol.17 No.4

Background and Purposes: Over the past three decades, numerous studies performed in Korea have reported that job stress is a determinant risk factor for chronic diseases and work disability. Every society has its own culture and occupational climate particular to their organizations, and hence experiences different occupational stress. An occupational stress measurement tool therefore needs to be developed to estimate it objectively. The purpose of this study is to develop and standardize the Korean Occupational Stress Scale (KOSS) which is considered to be unique and specific occupational stressors in Korean employees. Subjects and Methods: Data were obtained from the National Study for Development and Standardization of Occupational Stress (NSDSOS Project: 2002-2004). A total of 12,631 employees from a nationwide sample proportional to the Korean Standard Industrial Classification and the Korean Standard Occupational Classification were administered. The KOSS was developed for 2 years (2002-2004). In the first year, we collected 255 items from the most popular job stress measurement tools such as JCQ, ERI, NIOSH and OSI, and 44 items derived from the a qualitative study (depth interview). Forty-three items of KOSS, in the second year, were retained for use in the final version of the KOSS by using Delphi and factor analysis. Items were scored using conventional 1-2-3-4 Likert scores for the response categories. Results: We developed eight subscales by using factor analysis and validation process: physical environment (3 items), job demand (8 items), insufficient job control (5 items), interpersonal conflict (4 items), job insecurity (6 items), organizational system (7 items), lack of reward (6 items), and occupational climate (4 items). Together they explained 50.0% of total variance. Internal consistency alpha scores were ranged from 0.51 to 0.82. Twenty-four items of the short form of the KOSS (KOSS-SF) were also developed to estimate job stress in the work setting. Because the levels of the subscales of occupational stress were gender dependent, gender-specific standard norms for both the 43-item full version and the 24-item short form using a quartile for the subscales of KOSS were presented. Conclusion: The results of this study suggest that KOSS might be an appropriate measurement scale to estimate occupational stress of Korean employees. Further and more detailed study needs to be conducted to improve the validity of this scale.

노화가 인체 중간엽 줄기세포로부터 조골세포로의 증식 및 분화에 미치는 영향

백기현,태현정,오기원,이원영,조정기,권순용,강무일,차봉연,이광우,손호영,강성구,김춘추 대한내분비학회 2003 Endocrinology and metabolism Vol.18 No.3

연구배경: 일반적으로 골다공증과 연관된 위험인자로는 연령, 폐경, 약물, 불충분한 칼슘섭취, 만성질환 및 운동부족 등이 있는데, 특히 노화가 진행할수록 골밀도가 감소하는 것은 잘 알려져 있다. 노화와 관련하여 진행되는 골소실은 조골세포 및 전구조골세포의 기능적 결핍에 의한 골형성의 감소가 주요한 요인으로 여겨지고 있다. 그 동안 연령이 조골모 세포의 양과 조골모 세포로부터 성숙조골세포로의 분화 및 증식에 미치는 영향에 대한 일부 보고들이 있었으나 아직 일치된 견해는 없는 형편이다. 방법: 다양한 연령의 사람으로부터 골수를 채취, 중간엽 줄기세포가 포함된 단핵세포를 분리한 후 조골세포로 분화하기 좋은 조건하에서 배양하였다. 대상군은다시 젊은군과 노령군으로 구분하여 다양한 변수를 비교 분석하였다. 일차배양에서는 CFU-F를 계수하여 골수내 중간엽 줄기세포의 수를 추산하였고, 칼슘측정을 통하여 기질의 무기화 정도를 비교하였다. 계대배양후 이차배양에서는 시기별로 알카리성 포스파타제 활성도를 측정하고 오스테오칼신 mRNA의 발현을 관찰하여 젊은군과 노령군 사이의 증식능 차이를 비교하였다. 또한 이차배양 시기별로 MTT 측정을 하여 양군간에 증식능 차이가 있는지 알아보았다. 결과: 1. 일차배양 15일째에 평균 CFU-F의 수는 젊은군에서 유의하게 많았다(젊은군 148.3±28.9, 노령군 54.3±9.1, p=0.02). CFU-F의 평균면적은 젊은군에서 넓은 경향을 보였으나 통계적으로 유의하지는 않았다. 2. 일차배양 17일 경과 후 양군간에 기질 칼슘 침착정도는 유의한 차이를 보이지 않았다(젊은군 103.6±50.6, 노령군: 114.0±56.5, p=NS). 3. 이차배양 10일째에 젊은군에서 알카리성 포스파타제 활성도가 고령군에 비해 유의하게 높았다(젊은군: 935.5±115.0 U/mg, 노령군: 578.4±115.7U/mg,p.0.05). 고령군에서는 시간 경과에 따른 변화가 미약했으며 전반적으로 알카리성 포스파타제의 활성도가 젊은군에 비해 낮았다. 4. 이차배양도중 오스테오칼신 mRNA의 발현은 배양시기별로 젊은군에 비해 고령군에서 더 낮은 경향을 관찰할 수 있었다. 5. 이차배양 10일과 15일에 젊은군에서 노령군보다세포증식이 유의하게 증가된 양상을 보였다(10앓 젊은군 0.73±0.05, 노령군 0.58±0.04, p=0.05, 15일; 젊은군 0.80±0.05, 노령군 0.70±0.03, p=0.05).결론: 이상의 연구에서 저자들은 노령군에서 젊은군보다 골수 내 중간엽줄기세포의 수가 적고, 노령군에서 유래한 전구조골세포의 성숙조골세포로의 증식 및 분화가 젊은군 보다 감소해 있는 것을 관찰할 수 있었다. Background: Osteoblasts originate from osteoprogenitor cells in bone marrow stroma, termed mesenchymal stem cells (MSCs) or bone marrow stromal cells. Each MSC forms colonies (colony forming units-fibroblasts [CFL-Fs]) when cultured ex vivo. There are some reports about the age-related changes of the number and osteogenic potential of osteoprogenitor cells, but any relationship has not been clearly established in humans. In this study, we counted MSCs using CFU-Fs count and examined the proliferative capacity and differentiation potential of osteoprogenitor cells. Finally, we analyzed how these parameters varied with donor age. Methods: Bone marrow was obtained from the iliac crest of young (n=6, 27.2±8.6 years old) and old (n= 10, 57.4k6.7 years old) healthy donors. Mononuclear cells, including MSCs, were isolated and cultured in osteogenic medium. In primary culture, we compared the colony-forming efficiency of MSCs between the two groups and determined the matrix calcification. When primary culture showed near confluence, the cells were subcultured. Alkaline phosphatase activity, osteocalcin expression by RT-PCR and proliferative potential by MTT assay were examined by the time course of secondary culture. Results: At the 15th day of primary culture, the mean number of CFU-Fs was significantly higher in the younger donors (young: 148.3±28.9, old: 54.3±9.1, p=0.02) and the mean size of CFL-Fs was also larger in the younger donors than the older donors. However, matrix calcification was not different between the two groups (young: 103.6±50.6, old: 114.0±56.5, p=NS). In secondary culture, alkaline phosphatase activities were significantly lower in the older donors. The younger donors showed peak alkaline phosphatase activity at day 10, while the older donors didn't showed a remarkable peak (young: 935.5±115.OU/mg, old: 578.4±115.7U/mg, p<0.05). Total cell number as a proliferative index increased progressively during the secondary culture and a significantly greater cell number was noted in the younger donors. Osteocalcin expression was generally upregulated in the younger donors, but this was not statistically significant. Conclusion: Our study shows that the number of osteoprogenitor cells is decreased during aging and that the proliferative capacity and differentiation potential of osteoprogenitor cells seem to be reduced during aging (J Kor SOC Endocrinol 18:296-305, 2003).

고성군 덕명리 일대 공룡 생흔 화석 산지의 자연탐사와 교재화를 위한 연구

백광석,정호종,서승조,정우규 晋州敎育大學校 科學敎育硏究所 1994 科學敎育硏究 Vol.20 No.-

경남 도내 고등학생들을 대상으로 실시한 고장 자연 탐사에서 덕명리 해안의 지질과 교육적 활용성을 조사한 결과는 다음과 같다. 1. 덕명리 해안의 지층은 진동층에 속하며 공룡과 조류의 족혼 화석, 연혼, 건열, 화성암의 관입 등의 관찰되고 해식애, 해식동, 해식대가 발달하였다. 2. 공룡 족혼 화석은 2족보행 공룡인 Theropod 와 Ornithopod 및 4족보행 공룡인 Sauropod의 것으로 추정되었다. 3. 본지역의 특징은 중학교 과학 및 고등학교 과학 I 하와 지구과학 교과의 침식 . 운반 . 퇴적작용, 지층과 화석, 지질시대의 환경과 생물, 우리나라의 지질 등의 단원에 좋은 야외 지질교재이다. 4. 내 고장 자연 탐사교육은 학생들에게 학습의 동기와 흥미를 유발시킬 수 있는 대단히 유요한 프로그램이었고, 설문 조사 등 분석결과에 의하면 과학 교육적 성과도 있었다.

FDTD 기법을 이용한 도파관과 공동의 결합 해석

鄭白鎬,李華鎔,李範雨 호서대학교 공업기술연구소 2000 工業技術硏究所論文集 Vol.19 No.-

In this paper, an investigation of microwave coupling between waveguide and cavity with a lossy dielectric material by the Finite- Difference Time-Domain (FDTD) method is undertaken. We have assumed that the waveguide is excited by the magnetron which is modeled as a monopole with a delta gap source or frill generator. Numerical simulation indicates that the shape of cavity becomes very important when predicting the dissipated power distribution for a lossy dielectric material inside a cavity.

비선형 광섬유 신호의 수치해석을 위한 단계분할 유한요소법

鄭白鎬,李範雨,李鎬俊 湖西大學校工業技術硏究所 1999 工業技術硏究所論文集 Vol.18 No.-

In this paper, nonlinear Schrodinger equation have been analyzed to predict signal propagation in optical fiber using split-step finite element method (SS-FEM). Formulation was employed to take into consideration of dispersion, absorption and nonlinearity together. Also, higher-order term (β₃) in dispersion parameters could be treated by using cubic elements. Results obtained from SS-FEM were accurate comparing with some analytic solutions.

도심지 이동통신 신호 예측을 위한 회절 경로의 선행추적

鄭白鎬,李鎬俊,李種瑞 호서대학교 공업기술연구소 2000 工業技術硏究所論文集 Vol.19 No.-

Predetermination of diffracted rays to predict signal propagation in urban mobile commumication environment is proposed. This technique shows significant improvement in CPU time compared with conventional ray tracing method, and can be applied to any complex propagation environment composed of arbitrarily shaped buildings and streets. The predictions of this method are in good agreement with the measurement made in Tokyo and Ottawa.

顎矯正 手術 後 顎關節 障碍의 發現頻度에 關한 臨床的 硏究

백은호,이국엽,신효근,김정기 全北大學校 齒醫學硏究所 1992 전북치대논문집 Vol.10 No.1

The main purpose of the demanding surgical corrections aimed to improve esthetic appearance and masticatory function. But there are presumable etiologic factors in the development of T M symptoms after orthognathic surgery, that is, potential joint pathology due to different morphology of TMJ, hypombility after surgery, changes in condylar position, and changes in neuromuscular adaptation. These factors can influence on TMJ function. It is very important to find the etiological factors of TMD after surgery. Consequently, this survey was performed to evaluate TMJ function in 65 patients by questionaires, physical examination, radiogram after maxillofacial surgical corrections of the deformity patient. All patients were received pre- and post-operative orthodontic treatment. An acylic splint(wafer) was constructed prior to surgery with occlusal contacts in the anterior and posterior. The study group was consisted of 26 males and 39 females. The patients were evaluated at an average fellow-up period of 17.2 months with a range of 15 to 27 months. The results obtained were as follows: 1. The 65 patients were found to present preoperatively TMJ dysfunction symptom with an incidence of 18.5%(12 cases). 2. The patients with no TMJ dysfunction symptoms preoperatively, presented such symptom with an indicence of 26.4%(14 cases) postoperatively. 3. The main symptoms of TMJ dysfunction were 17 joints(15 clicking), TMJ pain(5 cases). 4. The mean preoperative MIO(maximal interincisal opening) of 49.7㎜ was reduced to 43.9㎜ postoperatively after sagittal split ramus osteotomy(n=38) with wire osteosynthesis(p<0.05).

WDM 시스템용 광대역 증폭기의 시뮬레이션

李鎬俊,沈雲用,鄭白鎬 湖西大學校工業技術硏究所 1999 工業技術硏究所論文集 Vol.18 No.-

In recent years, the biggest issue of WDM system is in increasing its bandwidth. Transmission bandwidth of WDM may be limited by many kinds of component, and the bandwidth plays impotent role in most of all optical amplifiers. Transmission bandwidth of recent WDM is limited in about 40 nm. This limit depends on EDFA(?? Fiber Amplifier) gain bandwidth. To overcome this problem, we may use L and S band using Yb/Nd doped fiber amplifier. Wideband amplifier, which is consisted of RFA for L band and EDFA for M band using single pump laser diode, is presented. The amplifiers have been analyzed numerically for the design.

심장수술 시 농축적혈구, 자가수혈기 혈액, 체외 순환기 혈액에서의 유리 혈색소 농도 비교

송장호,구승우,백종화,정용보,이정순,최인철 대한마취과학회 2002 Korean Journal of Anesthesiology Vol.43 No.5

Background: Intraoperative autotransfusion or residual blood in a cardiopulmonaty bypass (CPB) circuit has been used to reduce the need for an homologous blood transfutsion during cardiac surgery. However, it may contain some free hemoglobin released from damaged cells. The load of blood containing free hemoglobin may cause renal dysfunction. We measured the amount of free hemoglobin in backed blood, cell saver blood and CPB blood to evaluate what is the least hemolytic blood transfused in cardiac surgery. Methods: This study was performed in 20 patients undergoing cardiac surgery. In each patient, the banked blood, intraoperative salvaged blood with a cell saver and CPB residual blood were sampled at the end of the operation. The concentration of free hemoglobin, hemoglobin and platelet counts were measured in these blood samples and percent of hemolysis was calculated (%hemolysis = [free hemoglobin] / .free hemogloben + hemoglobin]) Results: In salvaged blood with a cell saver, CPB residual blood and banked blood, hemoglobin concentrations were 20.1 ± 2.7 g/dl, 8.0 ± 1.1 g/dl, and 22.2 ± 2.7 g/dl, respectively. Free hemoglobin concentrations were 336.6 ± 239.5 mg/dl, 49.2 ± 26.8 mg/dl, and 279.5 ± 167.5 mg/dl respectively. Platelet counts were 26.1 ± 22.2 × 10^3/mm^3, 116.8 ± 56.5 × 10^3/mm^3, and 94.9 ± 43.6 × 10^3/mm^3 respectively. % Hemolysis were 1.6 ± 1.1%, 0.6 ± 0.4%, and 1.2 ± 0.7% respectively. In the comparison between the salvaged blood with a cell saver and CPB residual blood, free hemoglobin concentration, % hemolysis, and platelet counts had positive correlations (r = 0.8, 0.7, and 0.6). Conclusions: In twenty cardiac surgeries, CPB residual blood had a lower free hemoglobin level than the other two blood groups. The platelet counts in CPB residual blood were higher than those in cell saver blood but did not differ from those in banked blood. Therefore, CPB residual blood was the least hemolytic blood among the three blood groups when a transfusion was performed in cardiac surgery. (Korean J Acesthesiol 2002; 43: 588~593)

초임계유체에 용해된 염료의 폴리에스터 섬유에 대한 염착

민정명,박민우,전정호,최백선,배효광 한국화학공학회 2004 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.42 No.2

반유통형의 초임계유체 염색장치를 사용하여 333.2K, 373.2K, 413.2K의 일정온도와 150bar-300bar의 압력에서 이산화탄소에 분산염료를 용해하여 폴리에스터 직물을 염색하고 염색시간에 따른 염착량을 측정하였다. 같은 방법으로 HFC-134a를 사용하여 383.2K와 413.2K의 일정온도와 50bar-160bar의 압력에서 염료를 용해하여 염색을 실시하고 염색시간에 대한 염착량을 측정하였다. 염착랑에 대한 초임계유체의 온도와 압력의 영향이 검토되었다. 이산화탄소와 HFC-134a의 초임계 용매를 비교하기 위하여 두 용매에 대한 염료의 용해도와 평형염착량의 관계를 검토하였다. 동일한 온도에서 HFC-134a를 초임계유체로 사용할 때보다 이산화탄소를 사용하는 것이 큰 평형염착량을 나타내었다. HFC-134a에 대한 염료의 용해도는 이산화탄소보다 훨씬 크지만 직물을 염색하는 초임계용매는 이산화탄소가 더 유리하였다. The uptake of disperse dye into polyester fiber in supercritical carbon dioxide was measured in the pressure range between 150 bar and 300 bar at each temperature of 333.3K, 373.2K and 413.2K, and the uptake in supercritical HFC-134a was measured in the pressure range between 50 bar and 160 bar at each temperature of 383.2K, 413.2K, using a flow-type apparatus with a cylindrical dyeing vessel. The effect of dye uptake in supercritical fluids on temperature and pressure was investigated. The dye uptake at constant pressure was much increased with temperature than it did with the pressure at constant temperature. The equilibrium uptakes of disperse dye in supercritical carbon dioxide were compared with those in the supercritical HFC-134a. The equilibrium uptakes in the supercritical carbon dioxide were much great than those in the HFC-134a at the same temperature. The supercritical carbon dioxide is better supercritical media than the HFC-134a, even though dye in the supercritical HFC-134a is much solved than in the supercritical carbon dioxide.