• Korean Chemical Engineering Research
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• 제49권2호
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• pp.238-243
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• 2011

본 연구는 기존의 인공심폐기의 단점을 보완하기 위하여 혈액펌프를 사용하지 않고 혈류의 흐름을 유도할 수 있는 기구(balloon)형 인공심폐기 설계를 위한 구조적 해석을 시도하였다. 가상의 모형 인공심폐기 내에서의 혈류의 흐름패턴을 분석하기 위하여 CFD 모델링 방법을 사용하였다. 이 시스템의 작동원리는 막 산화기 주위를 기구를 사용하여 압력하중을 인가하여 주기적으로 수축.이완되도록 하였으며, 시간에 따라 변화하는 시간 함수 값은 sine 반주기와 sine 주기를 계산하여 적용하였다. 이와 같은 방법으로 기구형 인공심폐기를 설계할 경우 한 방향에 대한 혈류의 움직임을 유도할 수 있다는 가정 하에 구조적 해석을 하였다. 실험결과 CFD 시뮬레이션을 통하여 인공심폐기의 입구와 출구에 서의 혈류의 속도와 압력을 측정하여 분석한 결과 한 방향에 대한 혈류의 유동이 발생하는 것을 확인하였다. 이와 같은 CFD 시뮬레이션은 혈류의 흐름특성을 미리 예측할 수 있어 인공심폐기 설계에 있어서 최적화된 디자인을 제공할 수 있을 것이라 판단된다.

• 생명과학회지
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• 제14권2호
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• pp.245-251
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• 2004

본 연구는 streptozotocin으로 당뇨병을 유도하는 조건들을 농도에 따른 변화를 관찰하고, 적절한 조건에서 당뇨쥐에서의 저강도의 treadmill 운동이 체중과 혈중의 당, 인슐린 및 지질의 변화에 미치는 영향을 알아보고자 실시하였으며, 연구결과를 요약하면 다음과 같다. 실험 I에서 STZ 주사량이 40 mg/mg으로 높아질수록 정상군에 비해 혈당이 유의하게 증가하고, 반대로 체중과 인슐린 농도는 상대적으로 감소하였다. 실험II에서 STZ 주사를 한 모든 군에서 혈당이 유의하게 증가하지만 BE군은 C군에 비해 그 증가율이 유의하게 억제되었으며, 운동이 인슐린 농도와 혈중지질 농도를 정상적으로 유도하는 것으로 나타났다. 특히, 당뇨 유발 전부터 운동을 실시한 경우 그 효과가 더욱 유의하게 나타났으며, 앞으로 당뇨 유발의 정도와 운동 빈도 및 강도와 관련된 더욱 많은 연구가 이루어져야 할 것으로 사료된다.

• Journal of Chest Surgery
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• 제38권2호
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• pp.101-109
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• 2005

배경: 심정지와 같은 위급상황에서 관상동맥의 혈류를 유지하는 것은 심장근육의 보존과 회복 및 환자의 생명을 보존하는 데 중요하다. 최근 들어 Extra-Corporeal Life Support System (ECLS)의 기계식 순환장치의 사용으로 심정지 환자의 생명을 보존하고자 하는 노력이 시도되고 있다 본 연구는 체외순환 모델에서 박동성 혈류와 비박동성 혈류가 관상동맥의 혈류량 및 심근에 미치는 영향에 대해 알아보고자 하였다. 대상 및 방법: 실험은 $25\~35Kg$의 돼지 14마리를 각각 7마리씩 두 군으로 나누어 진행하였다. 제 1군은 비박동성 혈류 펌프인 원심펌프를 사용하였고 제2군은 이중 박동형 펌프를 사용하였다. 체외순환은 우심방에서 상행대동맥으로 심폐바이패스를 하고, 9V의 전기 충격으로 심실세동을 만들었다. 체외순환은 2시간 동안 유지하였으며, 펌프량은 두 군 모두 2 L/min로 유지하였다. 초음파를 이용한 관상동맥 혈류 측정장치를 이용하여 좌전하행지의 관상동맥 관류량을 펌프 시작 전(기초치)과 시작 후 20분마다 측정하였다. 또한 관상 정맥동의 혈액을 펌프 시작 전(기초치)과 시작 후 1시간, 2시간에 채취하여 두 군간의 심근효소의 차이와 대사물질의 차이를 비교하였다. 각 관찰지표의 군간 비교는 STATISTICA 통계프로그램(Version 6.0)의 Mann-Whitney U test를 이용하였고 통계적 유의수준은 p값이 0.05 이하인 경우로 하였다. 결과: 관상동맥의 저항지수는 제 2군에서 낮게 나타났으며, 펌프 구동 후 40분, 80분, 100분, 120분에서 통계적으로 의미 있게 나타났다 (p<0.05). 관상동맥의 평균 혈류 속도는 제 2군에서 펌프 구동 후 20분부터 의미 있게 높게 유지되었다(p<0.05). 관상동맥의 혈류량도 제2군에서 높게 유지되었으며, 펌프 구동 후 40분, 60분, 100분, 120분에서 통계적으로 의미 있는 차이를 보였다(p<0.05). 그러나, 관상정맥동의 혈액학적 검사에서는 두 군간에 차이가 없었다. 결론: 박동성 혈류는 비박동성 혈류보다 좌전하행지 관상동맥의 저항지수를 낮추고, 관상동맥의 관류속도를 빠르게 하여, 관상동맥으로의 혈류량을 높게 유지하였다.

• 대한의생명과학회지
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• 제18권3호
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• pp.260-267
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• 2012

Obesity is associated with cardiovascular risk factors, such as dyslipidemia, hypertension and diabetes. However the presence of the obesity related deranged metabolic profiles varies widely among obese individuals. These individuals, known as 'metabolically healthy obese phenotype (MHO)', despite having excessive body fatness, display favorable metabolic profiles characterized by insulin sensitivity, no hypertension, as well as less dyslipidemia, less inflammation. The purpose of this study was to compare cardiac characterization and clinical profile of MHO and Non-MHO (nonmetabolically healthy obese) subjects in men. We measured treadmill exercise capacity (METs) and maximum blood pressure (BP) in 210 subjects through a medical checkup at J General Hospital. Metabolic syndrome was defined according to the modified Adult Treatment Panel III definition criteria. Both MHO and Non-MHO subjects showed statistically significant changes in the left ventricular mass index (P<.001, P<.01, respectively), A-velocity (P<.01, P<.001, respectively), E/A ratio (P<.01, P<.001, respectively), E'-velocity (P<.001, P<.001, respectively), HOMA-IR (P<.01, P<.001, respectively) and maximum systolic BP (P<.01, respectively) compared with the MH-NO (metabolically healthy non obese) subjects. In conclusion, MHO participants were at increased risk of cardiovascular disease and partly metabolic disorder.

• 대한의용생체공학회:의공학회지
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• 제28권6호
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• pp.777-785
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• 2007

In this paper, Finger-Toe Index (FTI) is proposed as an analytic parameter for the characterization of arterial vessel. Different from the currently being employed pulse wave velocity (PWV) information of the volume pulse wave measured from 4 arterial channels, the proposed FTI uses the ratio of the shorter of the two up-stroke time of PPG from fingers ($UT_{finger}$) and that of PPG (Photoplethysmography) from toes ($UT_{toe}$). To verify the usefulness of the proposed method, Finger-Toe Indexes were derived from the volume pulse waves acquired from 50 people under examination aged from 12 to 81 years old, and they were then compared with blood pressure ankle-brachial index (ABI). It was successfully demonstrated that the arterial stiffness can be estimated with respect to age and FTI is more strongly correlated with the pulse transit time than ABI. From the regression analysis, we also found that FTI has significant correlation PWV for a quantitative index of arterial stiffness and provides more accurate information than ABI for the characterization of arterial vessel.

• 보험의학회지
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• 제29권1호
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• pp.16-21
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• 2010

The measurement of prostate specific antigen (PSA) in screening for prostate cancer is recently performed as a routine check-up in clinical medicine and insurance medicine. Several factors may affect serum PSA levels. As prostate size increases with increasing age, the PSA concentration also rises. Increasing body mass index (BMI) is associated with a lower mean PSA concentration. Inhibitors of 5-alpha-reductase such as finasteride and dutasteride produce a 50 percent or greater decrease in serum PSA during the first three months of therapy, which persists as long as the drug is continued. Men who are regularly taking non-steroidal antiinflammatory drugs (NSAIDs) or acetaminophen have lower PSA levels. Emerging concepts regarding PSA testing that may help refine the interpretation of an elevated concentration include: PSA density, PSA velocity, and Free versus complexed or bound PSA. With many insurance companies, PSA level has become part of a standard battery of blood tests, along with HIV, cholesterol, liver enzymes, and other predictors of premature death. But, there is no clear proof of benefit, so we have to monitor the value of PSA test as a prostate cancer screening test in insurance medicine.

• 대한의생명과학회지
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• 제23권3호
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• pp.201-207
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• 2017

Measuring the pulse wave velocity (PWV) is a non-invasive method for evaluating the stiffness of the vessel wall. While previous studies investigated the association of uric acid level with arterial stiffness, most did not consider smoking status and obesity as covariates. The objective of this study was to investigate the relationship between uric acid levels and arterial stiffness, considering smoking status and obesity. We studied 3390 subjects (1940 males and 1450 females). Abnormal PWV was also defined as the highest quartile of values in the subjects. Data were analyzed using Pearson correlation, t-test, and multiple regression analysis. Approximately 41.9% of men and 3.7% of women were current smokers. Prevalence of hypertension was 11.4% in men and 7.0% in women. In women, hyperuricemia was associated with abnormal PWV (OR 1.58; 95% CI 1.03~2.43). Hyperuricemia was also associated with abnormal PWV (OR 2.37; 95% CI 1.01~5.59) in non- or light male smokers with normal blood pressure. This study suggests that uric acid is associated with arterial stiffness in women and non-smoking men.

• 한국전산유체공학회지
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• 제16권2호
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• pp.81-87
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• 2011

The importance of shear thinning non-Newtonian blood rheology on the hemodynamic characteristics of idealized cerebral saccular aneurysms were investigated by carrying out CFD simulations assuming two different non-Newtonian rheology models (Carreau and Ballyk models). To explore effects of vessel curvature, a straight and a curved vessel geometry were considered. The wall shear stress(WSS), relative residence time(RRT) and velocity distribution were compared at the different phases of cardiac cycle. As expected, blood entered the aneurysm at the distal neck and created large vortex in both aneurysms, but with higher momentum on the curved vessel. Hemodynamic characteristics such as WSS, and RRT exhibited only minor effects by choice of different rheological models although Ballyk model produced relatively higher effects. We conclude that the assumption of Newtonian fluid is reasonable for studies aimed at quantifying the hemodynamic characteristics, in particular, WSS-based parameters, considering the current accuracy level of medical image of cerebral aneurysm.

• Journal of Preventive Medicine and Public Health
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• 제28권2호
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• pp.398-405
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• 1995

We experienced a case of occupational lead poisoning employed in a secondary lead smelting plant for 12 years. The patient was 39-year-old male and had been felt dizziness, recent memory impairment and intermittent severe abdominal pain for 2 years. On admission, blood lead level was $92.9{\mu}g/dl$, urinary lead level was $19.9{\mu}g/l$ and zinc protoporphyrin level was $226.0{\mu}g/dl$. On the blood test, hemoglobin was 10.6g/dl and showed normocytic normochromic anemia. There were no abnormal findings in the biochemical and hormonal tests. Decrease of I.Q. and use of words in speaking were found in the psychiatric and psychologic examinations. We observed the finding of motor polyneuropathy in the nerve conduction velocity test. Computed tomographic finding showed calcification lesions in the basal ganglia, dentate nuclei, caudate nuclei, and especially characteristic multiple calcifications were located in the subcortical white matter.

• 한국의류학회지
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• 제23권7호
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• pp.980-986
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• 1999

This study was done to ivestigate the fabrics thatminimized harmfulness of UVB(ultraviolet B) and that might product Vit. {{{{ {D }`_{3 } ^{ } }} by UVB. Twelve female subjects wearing in three different types i.e fabric A(UVB 100% protection) fabric B(UVB 50% protection) and bikinii were exposed to outdoor environment (Air Temp : 25℃, 42% R,H Air velocity : 0.13m/s UV does :6KJ/m2) Blood samples were taken 24 hours before the after the experiment in order to examine concentration of vit.{{{{ {D }`_{3 } ^{ } }} in the blood. During the experiment axillary temperature skin temperature of 7 areas(forehead Chest Upper arm, Hand Thigh Lower leg, Foot) were measured. The more irradiated areas by UVB were the more the concentration of serum 25(OH){{{{ {D }`_{3 } ^{ } }} were significantly. Mean skin temperature was significantly low levekl in wearing the fabric of UVB 50% protection (p<0.001) Axillary temperature was significantly high level in wearing the fabric of UVB 50% protection (p<0.001). Therefore the fabric of UVB 50% protection intercepts the radiation and has advantage to give off body heat over other fabrics