휘발성 유기 화합물 가스 측정을 위한 전도성 고분자 센서의 제조 및 감응 특성

백지흠,황하룡,노진규,허증수,허덕동,임정옥,변형기 한국센서학회 2001 센서학회지 Vol.10 No.2

Conducting polymer sensors show high sensitivity when exposed to volatile organic compounds gases at room temperature. The 8 sensor array using by polypyrrole and polyaniline has been fabricated by chemical polymerization for measuring sensing characteristics of VOCs gases. Conducting polymer was polymerized by using distilled pyrrole, aniline as a monomer and ammonium persulfate (APS) as an oxidant and dodecylbenzene sulfonic acid (DBSA) as a dopant. Dedoped film was synthesized by reverse voltage and redoped film was synthesized by using 1-octanesulfonic acid sodium salt as another dopant in electrochemical cell. The sensitivity and reversibility were influenced by doping, dedoping, redoping and thiclrness for the polypyrrole and polyaniline. We investigated the relation between the structure of conducting polymer and sensitivity of these sensors through the analysis of scanning electron microscope (SEM), scanning probe microscope (SPM) and α-step.

운동 시기에 따른 수면의 질적 평가 수단으로서의 SWS 와 REM 의 타당성 검증

김정규,백일영,이복환 한국운동과학회 2000 운동과학 Vol.9 No.1

운동 시기에 따른 수면이 질적평가 수단으로서의 SWS와 REM의 타당성 검증. 운동과학. 제 9권 제 1호. (191)-(200), 2000. 본 연구의 목적은 서로 다른 운동 시기에 따른 수면의 질적평가 수단으로서의 SWS와 REM 수면의 변화 형태를 고찰함으로서 운동이 수면에 미치는 영향에 대한 타당성 있는 준거 기준의 검증을 통해서 운동과 수연의 관련성 규명에 필요한 과학적 기초 자료를 제공하는데 그 목적이 있었다. 본 연구의 모든 대상자들(5명)은 아침(08:00), 오후(14:00), 그리고 저녁(20:00)에 각각 자신의 80% VO₂max의 운동 강도로 더 이상 지쳐서 운동을 지속하지 못하는 시점까지 운동을 지속한 후, 수면 다원화 검사 방법을 이용하여 운동 후 수면 상태를 측정하였다. 서로 다른 운동 시기에 따른 운동 수행력의 변화는 통계 적으로 유의한 차이가 없었으나, REM과 SWS 수면 시간에 있어서는 운동 시기에 따라서 통계적으로 유의한 차이가 발견되었다(p<.05). 또한, 본 연구에서는 운동 스트레스에 대한 반응 지표로서 REM과 SWS에 대한 판별 분석을 통해서 SWS 수면 시간보다는 REM 수면 시간이 운동 스트레스에 대한 좋은 수면 지표로 나타났다. 따라서, 본 연구에서는 운동 시기에 따른 운동 스트레스에 대한 수면의 반응 지수로서는 SWS 수면 시간보다는 REM수면 시간을 통한 분석 방법이 더 타당한 것으로 나타났다. Verifying the Validity of Sleep Quality according to the Exercise timing. Exercise science, 9(1): 191-200, 2000. The purpose of this study was to verify the validity of sleep quality according to the exercise timing. The subjects of present study were 5 university students. All subjects participated in VO₂ max test to calculate their 80% VO₂ max workload. The exercise load tests were performed 3 times a day; morning exercise(A.M 08:00), afternoon exercise(P.M 2:00), and night exercise(P.M 8:00). All exercise test were continued until subjects stopped because of fatigue. To discriminate between wakefulness and sleep and to identify sleep stages, I performed measurement of EEG, EMG, and EOG using standardized procedures. There were no significant differences in exercise performance time, but there were significant differences in the SWS and REM time among the different exercises performed times(p<.05). REM sleep was a more resonable variable of exercise timing than SWS in the stepwise discriminant analysis. In this study, exercise performed in the late evening had a good advantage for sleep and also REM sleep was a more sensitive index of exercise-induces stress than SWS.

식물성 사료원료 내 피틴태 인의 함량과 PHYTASE ACTIVITY 및 그 특성에 관한 연구

엄재상,백인기,이선재,남궁환 한국영양사료학회 1999 韓國營養飼料學會誌 Vol.23 No.6

본 실험은 국내 사료회사들이 사용 중인 식물성 사료원료를 수집하여 phytate-P, total-P 그리고 phytase activity를 측정함으로써 가축이 필요로 하는 P의 적정 첨가량을 결정 할 수 있는 기초자료와 밀 phytase와 미생물 phytase의 pH 및 온도 변화에 따른 activity의 변화를 구명하고자 실시하였다. Phytate-P는 대부분 강피류에 많이 함유되어 있었다. 강피류 중에서도 미강 (1,201 ㎎/100g)과 탈지강 (1,077 ㎎/100g), corn gluten feed (896 ㎎/100g), 밀기울 (742㎎/100g) 그리고 채종박 (535 ㎎/100g)에 많이 함유되어 있었고, 다른 원료의 phytate-P는 500 ㎎/100g 이하였다. Total-P는 탈지강 (1,899 ㎎/100g), 미강 (1,886 ㎎/100g), 채종박 (1,016 ㎎/100g) 등에 많이 함유되어 있었다. Phytase activity는 밀 (1,121.9 U/㎏)과 밀기울 (2,935.1 U/㎏)에서 높은 활성을 보였다. pH와 온도의 변화에 따른 미생물 phytase와 밀 phytase의 activity는 모두 pH 5.5와 50℃를 전후하여 최고치를 나타내었다. 그러나 pH 6과 60℃ 이상에서 급격히 감소하는 경향을 보였다. 밀 phytase 보다는 미생물 phytase가 보다 더 급격히 감소하여 식물성 phytase가 pH와 온도변화에 대해서는 내성이 더 강한 것으로 나타났다. An experiment was conducted to measure the contents of phytate-P, total-P and phytase activity of cereals and cereal by-products. The effects of pH and temperature on the activity of wheat and microbial phytase were compared. Phytate-P content was higher in most cereal by-products than in cereal. Rice bran had the highest phytate-P (1,201 ㎎/100g) followed by defatted rice bran (1,077 ㎎/100g), corn gluten feed (896 ㎎/100g), wheat bran (742 ㎎/100g) and rapseed meal (535 ㎎/100g). The phytate-P contents of other ingredients were lower than 500 ㎎/100g. Total-P content was high in defatted rice bran (1,899 ㎎/100g), rice bran (1,886 ㎎/100g), and rapseed meal (1,016 ㎎/100g) compared to other ingredients. Wheat and wheat bran had the highest phytase activity (1,121.9 and 2,935.1 U/㎏) among ingredients tested. The activity of wheat and microbial phytase was gradually increased until pH and temperature reached at 5.5 and 50℃ respectively, then their activity remarkably decreased at pH 6 and 60℃. Wheat phytase was as stable, if not more, as microbial phytase under different pH and temperature.

장기간 유산소 훈련이 RICO RAT 의 심박수 , 혈압 및 지질 성분 변화에 미치는 영향

곽이섭,백일영 한국운동과학회 2000 운동과학 Vol.9 No.1

장기간의 유산소 훈련이 RICO RAT의 심박수, 혈압 및 지질 성분 변화에 미치는 영향. 운동과학. 제 9권. 제 1호 (29)-(39), 2000. 본 연구의 목적은 같은 계열의 고지혈쥐(RICO) 25마리를 대상으로 하여 10주간의 정기적인 유산소 훈련이 심박수, 혈압, 및 혈중 지질성분에 미치는 영향을 살펴봄으로써, 신드롬 X의 증세를 나타내는 가계에서 유산소 훈련의 효과를 규명하는데 목적이 있었다. 실험에 사용한 동물은 6주령의 안정시 분석그룹(CR; control resting), 6주령의 일회고강도 운동반응 후 분석그룹(CE; control exercise), 16주령의 안정시 분석그(CA; control aged), 16주령의 안정시 유산소 훈련에 대한 분석그룹(TR; trained resting), 16주령의 훈련군에서 고강도 운동반응 후 분석그룹(TAE; training aged exercise)의 총 5그룹으로 구분하였다. 실험동물의 훈련은 총 10주간의 수영훈련으로서 25℃-27℃의 수온에서 1주간의 환경적응과 1주간의 수영 적응훈련 후, 본 운동 시간을 5분간 점진적으로 증가시켜 30분 시점에서는 훈련 마지막까지 지속하였다. 본 실험의 혈압 및 심박수의 측정은 일본 Muromachi kikai(社)의 BP Monitor MK-1100을 사용하었고, 지질성분의 측정은 일본 Hitachi 747과 7150을 이용하여 분석하였다. 유산소 훈련에 따라서 체중의 변화가 훈련 2주차부터 현저한 차이가 나타나 통계적으로 유의한 차이가 발견되었다(p<.01). 또한 심박수 및 혈압의 변화도 그룹간에 유의한 차이가 나타났으며, 훈련군에서 증가되는 수치가 나타나 통계적으로도 유의한 차이를 보였다(p<.01). 혈중 지질성분 중 T-C와 HDL-C는 연령의 증가에 따라 증가되는 수치를 나타내었고, TG와 LDL-C는 연령에 따라 감소하는 수치를 나타내었지만 HDL-C를 제외한 모든 지질성분은 유산소 훈련에 따라서 현저하게 감소하는 수치를 나타내었으며, 일회 고강도 운동반응에서 모든 지질성분은 증가하여 통계적으로 유의한 차이가 발견되었다(p<.01). 본 연구에서는 정기적인 유산소 훈련이 성장기에 있는 고지혈쥐에게서 체중의 감소, 심박수 및 혈압의 증가와 혈중 지질성분의 감소를 나타내었고, 상대적으로 HDL-C의 증가를 통만 지질대사의 활성화를 일으켜 고지혈쥐의 위험요인을 감소시켰다. 아울러 고지혈 현상으로 나타난 면역기능의 감소가 정기적인 유산소 훈련을 통하여 지질성분의 감소와 더불어 활성화 되는지, 항산화체제와는 어떠한 관련성이 있는지에 대한 추가적인 연구가 절실히 필요하다고 본다. The effect of prolonged exercise on the cirrelation pf lipiditems and immune system. Exercise Science, 9(1): 29-39, 2000. The purpose of this study is to investigate the effects of swimming training on heart rate, blood pressure, and blood lipid levels in RICO rats. Twenty five male RICO rats(six weeks old) were divided into five groups: five control resting (CR), five control exercise (CE), five control aged (CA), and five trained resting (TR), and five training aged exercise (TAE). TR and TAE groups of the present study participated in a regular training program five times per week for ten weeks, whereas CR, CE, and TAE groups did not participate in the training program. Blood sampling were taken in the laboratory in the Department of Animal Medicine at the Yonsei Medical Research Center, and were analyzed for blood lipids (LDL, T-C, TG, and HDL-C). All data were expressed as mean and standard deviations by using the SAS program (version 6.12), and were analyzed using the one-way analysis of variance to evaluate the difference of these inter- groups. In the mean body weight, there was a significant difference between the CE and TR groups (p<0.01). Heart rate and blood pressure were also significantly different among the CR, CA, and TR groups (p<0.01). In the mean blood lipid level, there was a significant difference among the CR, CE, CA, TR, and TAE groups (p<0.01). Due to regular exercise training, all of the blood lipid levels were decreased greatly except for HDL-C: all of the blood lipids levels were increased after highly intensive exercise in the CE and TAE groups. In this study, we can conclude that regular exerdse training decreases body weight and blood lipid levels except HDL-C, increases heart rate and blood pressure in RICO rat, and also we can say that regular training protect syndrome X disease in the model of RICO rat.

Wustite 의 전기전도도에 미치는 제3원소의 영향

백영현,김경대 고려대학교 공학기술연구소 1984 고려대학교 생산기술연구소 생기연논문집 Vol.20 No.1

Electrical conductivity measurements were respectively made on synthetic wustites which were doped with dilithium oxide. dialuminum trioxide and silicon dioxide in the temperature range of 20℃ to 1,000℃. The D.C. conductivity of the wustite was measured by means of the two-prove method. Their electrical conduction were found to be characterized by a typical semiconductor behavior. A plot of logarithm of conductivity versus reciprocal temperature was fairly linear, and the activation energy calculated there from was approximately 0.12eV below about 600℃. whereas above that temperature 0.042eV, Electrical conductivity of the wustite was increased by adding Li₂O or CaO and on the other hand decreased by adding Al₂O₃ or SiO₂ into wustite. This behavior could be explained in terms of lattice defect structure. It was found that the electrical conductivity of wustite was practically proportional to the concentration of electron hole i.e. Fe^(+3) in the lattice.

간세포암과 주위 조직에서의 Transforming Growth Factor-beta 1과 그 수용체의 발현

최규완,백승운,최문석,김소정,이준혁,고광철,이풍렬,이종철,박상종,안병훈,김재준 대한소화기학회 2001 대한소화기학회지 Vol.37 No.4

Background/Aims: Transforming growth factor-beta 1 (TGF-β1) is a potent inhibitor of hepatocyte proliferation and its receptor is known to be involved in the carcinogenesis. This study was designed to compare the expression levels of the TGF-β1 and its receptor in neoplastic cells and its surrounding tissue and to assess their role in hepatic carcinogenesis. Methods: We measured the levels of TGF-β1 mRNA and TGF-β1 receptor II mRNA by semiquantitive RT-PCR for the tumor and its surrounding tissue of 30 patients with hepatocellular carcinoma (HCC). We analyzed the relationship between the expression of TGF-β1 mRNA, TGF-β1 receptor II mRNA and clinicopathological characteristics of HCC. Results: The expression of TGF-β1 mRNA showed no difference between HCC and its surrounding tissue, but the expression of TGF-β1 receptor II mRNA was lower in HCC than in its surrounding tissue (2.47±1.08 vs 3.53±1.50, p=0.00). There was no difference in the expression level of TGF-β1 mRNA and TGF-β1 receptor II mRNAo the clinicopathological characteristics of HCC. However, the ratio of TGF-β1 receptor II mRNA in HCC to that in surrounding tissue was more decreased in HCC with portal vein invasion (0.49±0.22 vs 0.77±0.21, p=0.01). Conclusions: Our data suggest that the loss of TGF-β1 receptor II may play an important role in carcinogenesis and tumor progression of HCC.

슬라브의 연속주조시 냉각에 대한 수학적 모델

고창호,현종각,백영현 고려대학교 공학기술연구소 1986 고려대학교 생산기술연구소 생기연논문집 Vol.22 No.1

A mathematical model describing heat transfer in the continuous casting of slab is proposed. The model consists of a unidimensional transient conduction equation arid boundary condition equations which specify heat flux at the metal-mold interface. The proposed model is characterized by followings: 1) the length of the mush (liquid-solid) region was estimated by experimental data and 2) the internal heat generation term was introduced to the main heat balance equation. By using FDM, cooling of slab was simulated at various casting conditions, and surface temperature as well as the locations of liquidus and solidus were determined as a function of casting distance. The results thus obtained revealed that the model fits better for the measured temperature profile.

췌장암에서 Cyclooxygenase - 2 발현의 역할

김은경,이용욱,이규택,최규완,박동일,백승운,이준행,이종균,고광철,이풍렬,이종철,김재준,김완선,공구 대한소화기학회 2001 대한소화기학회지 Vol.38 No.3

Background/Aims: Accumulating evidence suggests that the use of NSAID may reduce the incidence of colorectal cancer. The likely mechanisms of these effects by NSAID is cyclooxygenase-2 (COX-2)-related inhibition of tumor proliferation and induction of apoptosis. The aim of our study was to examine possible roles and clinical significance of COX-2 expression in pancreatic cancer. Methods: Seventy-two pancreatic adenocarcinoma tissue specimens were obtained from surgical resection. After the immunohistochemical staining of the specimens, we examined proliferation activity (assayed by Ki-67 expression), apoptosis (by TUNEL stain), and microvessel density (by CD34 expression). We also investigated the relationship between the immunohistochemical expression of COX-2 and various clinicopathological characteristics. Results: The COX-2 positive rate in pancreatic epithelial cells was 41.7%. Proliferation index (PI) was significant higher in COX-2 positive specimens comparing to negative specimen (p=0.015) and the increase in intensity of COX-2 expression correlated with increasing PI (p=0.036). Apoptotic index (AI) was significantly higher in positivee COX-2 expression than in negative expression (p=0.044), but there was no significant difference in AI/PI between the COX-2 positive and negative specimens (p=0.44). The expression of COX-2 protein did not correlate with microvessel density, sex, age, differentiation, tumor size, stage, metastasis or patients survival. Conclusions: The expression of COX-2 enzyme in pancreatic cancer contributes to tumor proliferation, but is not related to apoptosis, angiogenesis or clinical characteristics. Further study is needed to examine the clinical usefulness of NSAID and COX-2 selective inhibitors.

산업보건 및 환경분야에 대한 활동기준원가계산 및 관리의 응용

백남원,박두용,마이클티브랜트,스티븐피르빈 한국산업위생학회 1996 한국산업보건학회지 Vol.6 No.1

During the 1990s the workplace has grown more complex and business competition has increased world-wide. All organizations, whether for-profit or non-profit have been forced to respond to market changes. More advanced information and technology, greater product diversity, shorter product life cycles, increased quality requirements, more regulation oversight, decreasing productivity, more competitors, and increasing overhead costs have motivated organizations to focus on ways to deliver products cheaper, better, and faster. Many organizations are searching for ways to reduce costs through downsizing, reengineering business processes, implementing quality management, outsourcing, and improving cost management. Support departments that provide services internal to an organization such as human resources, legal, and environmental, safety, and health (ES&H) are often the first organization targeted for cost reduction and cost control initiatives because these functions are part of a rapidly increasing overhead cost. Recently, ES&H functions are increasingly being integrated into the business of business to contribute value to organization beyond mere compliance with ES&H regulations. The discussions and development of the ISO compatible Environmental Management Standards or Occupational Safety and Health Management Standards is another impetus to integrate ES&H function into the business of business. Thus, ES&H professional need new skills to analyze the cost of their function and communicate the value of the products and services they provide. In recent years, the need for and the importance developing cost management and business skills by ES&H professionals have been emphasized in the literature. Communicating with decision makers in terms of cost and value to the organization, and by using business language and business arguments is the first step toward effectively integrating ES&H activities into the business of business. Activity-based casting (ABC) is a cost management method that measures the cost of a product or service loosed on the actual use of resources by activities, and based on the actual amount of activities used to produce a product or service. ABC is recommended as a tool for managers of ES&H organizations to determine the cost of developing and providing ES&H products within a for-profit firm or non-profit agency. This paper discusses the trend of integration of ES&H functions into the mainstream of business activities within an organization. The general principles of traditional cost accounting are presented as a bases for understanding why and how ABC will provide more accurate estimates of cast. The principles and concepts of ABS are presented as a tool for determining mire accurately the true cost of ES&H products and services.

역류성 식도염 환자에서 Helicobacter pylori 치료 1 년 후 증상과 내시경적 변화

김영호,손희정,최규완,박동일,백승운,이준행,고광철,이풍렬,이종철,임윤정,김재준 대한소화기내시경학회 2001 Clinical Endoscopy Vol.24 No.1