• Journal of Preventive Medicine and Public Health
• /
• v.30 no.4 s.59
• /
• pp.791-804
• /
• 1997

Irritable bowel syndrome(IBS) is one of the common health problem that has been considered as stress-induced. This study was conducted to investigate the relationship between life style and the level of stress and IBS by structured questionnaire which included questions on life style, the self-esteemed gastrointestinal symptoms, and Psychosocial Well-being Index(PWI). Subjects were 1,498 male white collars who get the regular health check and participated in survey at Inje University Health Promotion Center from January to ,December, 1996. The overall prevalence of IBS was 37.5%(561 cases), and the level of stress by PWI score was higher in IBS group$(41.8{\pm}14.2)$ than symptom-free group$(34.6{\pm}12.6)$. As the result of comparison between the two groups, heavier smoking (adjusted O.R=2.48, 95% C.I 1.81-3.41), longer daily working time (adjusted O.R=5.19, 95% C.I 3.59-7.56), stimulatory food materials-mainly hot or salty (adjusted O.R=1.87, 95% C.I 1.44-2.45), higher body mass index (adjusted O.R=1.80, 95% C.I 1.27-2.57), and higher level of stress (adjusted O.R=2.81, 95% C.I 1.80-4.43) were estimated as risk factors of IBS. On the contrary, 6-8 hours sleeping per day (adjusted O.R=0.38 95% C.I 0.21-0.70), 3-4 times exercise per week (adjusted O.R=0.57 95% C.I 0.39-0.83), and tenure more than 20 years (adjusted O.R=0.25 95% C.I 0.16-0.35) were considered as protective factors to IBS. In summary, the assessment of the stress level might be placed in the first priority to control IBS, at least by some degree, which suggested that IBS could be controlled by avoiding such risk factors and by encouraging such protective factors.

• Applied Biological Chemistry
• /
• v.49 no.4
• /
• pp.309-314
• /
• 2006

This study was performed to confirm the physicochemical properties and physiological activities according to cultivar and parts of Ulsan sweet persimmons. The proximate composition of the sweet persimmons was moisture $77.68{\sim}84.65%$, crude ash $0.3{\sim}0.6$, crude fat $0.29{\sim}0.39$ and crude protein $0.52{\sim}0.61%$. Confirmed organic acids and free sugars in sweet persimmons were malic, citric, succinic, and fumaric acids, along with fructose, glucose and sucrose. The major fatty acids were linolenic, vaccenic and palmitic acids. Also, K is the highest mineral in sweet persimmons that accounts for the majority of mineral, more than 60% as $84.9{\sim}103.7mg%$. Contents of vitamin C, total phenolic compounds and flavonoids were the highest in Fuyu peel as 139.91, 169.36 and 60.79mg%, respectively, Electron donating ability and xanthine oxidase inhibition were the highest in Fuyu peel as $30.6{\sim}91.2$ and $26.3{\sim}91.9mg%$, respectively. Nitrite scavenging activity was higher in peel than flesh as $51.0{\sim}76.4mg%$ with slight difference depending on cultivar.

• Journal of the Korea Safety Management & Science
• /
• v.22 no.3
• /
• pp.1-8
• /
• 2020

The desulfurizers facility is cylindrical shape. To operate properly it needs nozzles cleaned, get rid of lime adhesion and sludge, repair the wear and corrosion of facility regularly. For this purpose, workers shall access the ceiling or vertical wall at high place. Ordinary scaffoldings such as steel pipe scaffolding or system scaffolding have been using so that workers can access them. With these ordinary scaffoldings, openings around cylindrical wall are inevitable which make workers can expose always to the risk of falling. The purpose of this study is to develop customized scaffolding to minimize the openings to prevent workers form falling during maintenance it. It consists of a hexagonal central tower and six trapezoidal outer towers. And the bracing among the towers have connected each other for self-standing and for maintaining the structure of towers. Span decks, the circumference footstools, steps, etc. are laid on each floor. The safety is reviewed by structural analysis and performance test. With this study, openings each floor of this scaffold are removed. The gap between the cylindrical wall and the edge of the work stage is approximately 100 mm. Therefore, we expect that workers can work safely and efficiently.

• Journal of the Society of Naval Architects of Korea
• /
• v.34 no.3
• /
• pp.27-37
• /
• 1997

The paper deals with the effectiveness of various special rudders on course stability of a ship. We adopted five types of rudder, such as one normal rudder and four special rudders, which contain two rudders with concave and convex strips on sides respectively, one flapped rudder, and one rudder with end plates on tips. In the circulating water channel, model test was carried out for measuring lift characteristics of the rudders in open water. And various captive model tests were also carried out for measuring the experimental constants related with helm angle and steering in hull-propeller-rudder system. From the test results, the changes in manoeuvring hydrodynamic derivatives due to adoption of normal and special rudders were predicted. Then course stability performances of a ship with normal and special rudders were evaluated and discussed. As a result, it is clarified that the rudder with concave or convex strips and flapped rudder have no effect on course stability, while the rudder with end plates improves course stability with effect. The result in this study is expected to be used usefully when the course stability is in issue and has to be improved without amendment of hull design at initial design phase or after construction of a ship.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.19 no.6
• /
• pp.1557-1562
• /
• 2005

A mechanism of hair cell damage caused by noise and ototoxic agents is mediated through generation of free radicals and reactive oxygen species (ROS). It is known that most of animals have defense systems to protect against ROS, and the cochlea of inner ear in animals also has ROS defense systems including several antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR), and glutathione (GSH), which efficiently detoxifying ROS generated under normal condition. Steamed roots of Rehmannia glutinosa have been traditionally used in Oriental medicine for the treatment of auditory disease such as tinnitus, vertigo, and hearing loss as well as inflammatory diseases, hectic fever, night sweat, and headache. In the present study, we showed that the ethanol extract from steamed roots of R. giutinosa (ESRG) increased the antioxidant enzymes such as SOD, CAT, GPX, and GR activities and GSH level in HEI-OC1 auditory cells. This extract itself did not show any significant cytotoxicity up to $50{\mu}g/ml$. Our results further support the view that ESRG is promising sources of potential antioxidants. Future studies will be aimed at investigating the effects of ESRG on the regulation of cellular mechanisms and isolating and identifying the substances responsible for the regulation of antioxidant enzyme system from the plant extracts.

• Journal of Plant Biotechnology
• /
• v.40 no.3
• /
• pp.125-134
• /
• 2013

Lipid droplets called plastoglobules are present in all plastid types. In chloroplasts, they are surrounded by the outer lipid monolayer from and connected to thylakoid membrane. The plastoglobule core contains the neutral lipids, which includes prenylquinones, triacylglycerols, and carotenoids. During stress and various developmental stages such as senescence, the size and number of plastoglobules increase due to the accumulation of lipids. Plastoglobules proteome revealed the presence of metabolic enzymes as well as structural proteins, plastoglobulins/fibrillins. Among the metabolic enzymes, the tocopherol cyclase, VTE1 and the NADPH quinine dehydrogenase, NDC1 have demonstrated that these participate in isoprenoid lipid metabolic pathways at the plastoglobule, notably in the metabolism of prenylquinones (tocopherol, plastoquinol and phylloquinone).

• Proceedings of the Korea Water Resources Association Conference
• /
• 2007.05a
• /
• pp.612-616
• /
• 2007

오랫동안 홍수조절, 용수공급, 전력생산, 레저 활동을 위해 건설된 댐들은 하천이나 호소의 생태적 기능보다는 치수 및 이수기능이 중요시되면서 운영 관리되어 왔다. 하지만 최근 들어 선진국을 중심으로 환경 및 생태의 중요성이 인식되면서 하천생태계 보호를 위한 환경유량 산정이 언급되고 있는데 이는 하천이 동 식물의 서식처로서 적절한 수질뿐만 아니라 수심, 유속, 하상재료, 먹이원, 어류를 보호할 수 있는 휴식 및 은신처 등의 다양한 조건을 제공할 수 있어야 한다고 제시되고 있다. 이들 조건 중 유량(Flow)은 하천에서 생물집단을 구성하는데 있어 물리적 서식조건의 주요한 결정인자로 작용하는데, 댐 하류하천의 자연유량(natural flow)을 변화시키면 생태학적 측면에서 기대치 않던 영향을 야기할 수 있다. 따라서 댐 건설 전 후의 자연유량과 조절유량 사이에서 생태학적 어류조사연구를 통한 차이점을 찾는 것은 매우 중요하다고 볼 수 있다. 본 연구의 최종목적은 수계 내 댐 건설 전 후의 어류군집과 유량 등 수리조건과의 연관성을 분석하여 하천구간별로 어류생태에 적합한 유량을 산정하는 것이다. 조사대상 구간은 금강본류를 대상으로 하되 용담댐과 대청댐을 중심으로 하여 10개 구간을 선정하였고. 과거로부터 2000년도까지와 용담댐 건설후인 $2002{\sim}2004$년도에 조사된 어류생태자료를 활용하였다. 용담댐 상류로부터 대청댐 하류에 이르기까지 전 구간을 대상으로 조사된 자료를 분석한 결과 총 20과 82종이 출현하였고, 이중 종 45종(54.9%)이 잉어과에 해당하며 미꾸리과(6종), 동자개과(4종), 망둑어과(5종)를 제외한 대다수의 분류군(Family)들은 단일 또는 2종으로만 구성되었다. 이들 중 천연기념물 제 259호로 지정되어 법적으로 보호되고 있는 어름치(금강에서 서식한 어름치를 따로 천연기념물 238호로 지정함)를 비롯하여 다묵장어를 포함한 7종의 멸종위기종이 확인되었다. 또한 각시붕어 등 총 29종(39.4%)의 높은 한국고유종 출현과 6종의 외래도입종도 확인되었다. 금강의 중 상류에 해당하는 구역을 포함하는 대청댐 상 하류 구간에서 대청댐 건설 전(1980년 이전)을 포함하는 2000년 이전 조사 자료가 가장 다양한 어류상과 특이어종(멸종위기종 및 한국고유종)을 보였고, 최근자료$(2002{\sim}2004)$를 살펴볼 때 용담댐 상 하류에서보다 대청댐 상 하류에서 멸종위기종(7종$\rightarrow$1종) 및 한국고유종(28종$\rightarrow$16종)의 출현감소와 외래도입종의 출현증가(1종$\rightarrow$6종)와 같은 주요한 어류군집 변화를 보였다. 이는 댐 건설에 따라 주로 계류성 어종을 중심으로 정수역 구간에서 인근 지류로 이동하게 되고 일부는 제한된 서식공간과 하천교란으로 인해 개체군이 극감하거나 일부 소멸된 종이 발생하였을 것으로 사료된다. 실측 유량자료 분석에 의하면 홍수기 최대유량 변화는 크지 않으나, 갈수기 최소유량은 크게 증가한 것을 알 수 있었고, 대다수 어류의 산란기인 봄철(5월, 6월) 최소유량은 증가하였으나, 최대유량은 감소한 것으로 분석되었다. 이러한 변화는 어류생태계에 긍정적인 면과 부정적인 면이 있으며, 향후 이러한 영향을 분석하기 위해 선택어종(Target species)별 생태환경 서식조건을 확인할 수 있는 조사기법 및 자료구축이 절실히 필요한 실정이다.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2002.11a
• /
• pp.29-29
• /
• 2002

공구강 등 산업용 재료로 널리 사용되는 카바이드 계 재료는 입자 크기 및 분포에 따라 기계적 성질이 변화하므로, 이를 제어하고 조절하는 기술에 관하여 많은 연구가 진행되어 왔다. 본 연구에서는 TiCN-WC-Co 복합초경계 에서 소결 공정 및 조성변화에 따른 입자 모양을 관찰하고 이에 따른 업자 성장 거동을 고찰하였다. 일반적으로 입자 조대화 양상과 고상 입자의 모양과는 밀접한 관계가 있다. 각진 입자의 경우에 는 계면이 원자적으로 singular 하여 원자의 홉착이 어렵기 때문에 임계값 이상의 성장 구동력을 받 는 몇몇 입자만 성장하는 비정상 입자 성장이 일어날 수 있다. 반면에 계면이 rough한 퉁큰 엽자의 경우에는 원자 홉착에 필요한 구동력이 존재하지 않아 성장 구동력을 받는 모든 입자들이 성장하기 때문에 정상 입자 성장을 하게 된다. 이와 같이 입자 모양에 따른 입자 성장 거동은 전체 미세구조를 결정하게 되며, 이에 따른 물리 화학적 물성을 변화시킨다. 이러한 입자 성장 원리를 적용하 면 복합초경계 (TiCN-WC-Co)에서도 입자성장이 억제되고 치밀한 소결체를 제조할 수 있을 것이다. 본 실험에서는 평균입도가 각각 0.1, 1.33, 2$\mu\textrm{m}$인 TiCN, WC, Co 분말을 사용하여 $((I00_{-x)}TiCN+_xWC)-30Co$ (wt%) 조성에서 TiCN/WC 비를 변화시키면서 업자 모양과 입자성장 거동을 관찰하였다. 청량된 분말은 WC 초경 볼로 밀렁하고, 건조한 후, 100 mesh 체로 조립화 하였다. 이 분말을 100 MPa의 압력으로 냉간정수압성형 하고 $10^{-2}$ torr의 진공분위기의 graphite f furnace에서 carbon black으로 packing 하여 액상형성 온도 이상에서 소결하였다. 소결된 시편은 경면 연마하여 주사전자현미경으로 미세 조직을 관찰하였다. TiCN-30Co 조성 시편은 corner-round 모양의 입자 모양으로 소결 시간 증가에 따라 빠른 입자 성장을 나타내었다 .(7STiCN+2SWC)-30Co 조성 시변의 경우 일반적으로 보고된 바와 같이 core/shell 구조를 나타내었으며, core는 TiC-rich 상이었고, shell은 (Ti,W)(C,N) 복합 탄화물 상이었다. WC 함량이 중가함에 따라 입자의 corner-round 영역이 증가하였으며 (SOTiCN-SOWC)-30Co 조성 근처에서는 거의 둥근 형태의 입자 모양을 나타내었다. 또한 TiCN - 30Co 조성 시편에 비하여 WC가 첨가된 시펀들은 작은 평균입자크기를 나타내었다. 본 연구의 결과는 shell 영역 조성 변화는 계면에너지 이방성과 기지상 내의 펑형 입자 모양을 변화시키고 나아가 입자 성장 속도 에도 영향을 미친다는 것을 보여준다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.21 no.2
• /
• pp.109-121
• /
• 2003

Lots of various utilities are buried under the surface. The effective management of underground utilities is becoming the very important subject for the harmonious administration of the city. Ground Penetrating Radar(GPR) survey including other various underground survey methods, is mainly used to detect the position and depth of buried underground utilities. However, GPR is not applicable, under the circumstances of shallow depth and places, where subsurface materials are inhomogeneous and are composed of clay, salt and gravels. The aim of this study is to overcome these limitations of GPR and other underground surveys. High-frequency electromagnetic (HFEM) method is developed for the non-destructive precise deep surveying of underground utilities. The method is applied in the site where current underground surveys are useless to detect the underground big pipes, because of poor geotechlical environment. As a result, HFEM survey was very successful in detecting the buried shallow and deep underground pipes and in obtaining the geotechnical information, although other underground surveys including GPR were not applicable. Therefore this method is a promising new technique in the lots of fields, such as underground surveying and archaeology.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.4
• /
• pp.319-324
• /
• 2016

Soils with various particle sizes generally show good shear strength. Some soils have a relatively strong resistance to shear failure in spite of narrow particle distribution, such as gap grading. Based on this example, it can be inferred that appropriate arrangements of particle size in soils might result in an increase in shear strength. This study investigates the strength variation of soils with respect to the particle size distribution. Gap, well, and uniform graded soils were prepared with a desired ratio, and a wide range of direct shear tests were done using the prepared samples. The test results show that there is a strong relationship between the particle size ratio and internal frictional angle. Gap graded soil has a greater frictional angle than a well-graded sample, even when specimens have the same maximum particle size, which is also the case for the uniform grade specimen. The results have potential for developing a methodology for stronger soils through a simple manipulation of particle size distribution.