혈청 총 콜레스테롤과 혈압, 비만 및 일상 생활습관의 관련성에 관한 연구

진복희,김주영 대한보건협회 1995 대한보건연구 Vol.21 No.2

고혈압과 동맥경화성 지질의 상승은 매우 높은 관련성을 갖고 있으나, 그 상관성에 대한 역학조사에서는 일치된 결과를 보여주지 못하고 있다. 고혈압과 혈청 지질의 관계를 명확히 규명하는 것은 고혈압이 어떻게 관상동맥 질환의 위험요인으로 작용하고 있는지에 대한 기전을 밝히는데 중요한 정보를 제공할 수 있다. 본 연구는 30-69세의 직장 성인 남자 5,011명(평균연령 50.5±9.9)과 여자 1,171명(평균연령 577±9.0)을 대상으로 혈청 총 콜레스테롤과 혈압 및 기타 신체지수와의 관련성을 조사하였다. 혈청 총 콜레스테롤과 혈압, 체중 등은 공복시에 측정하였으며, 가족력, 음주 및 흡연습관은 설문지를 통하여 조사하였다. 수축기 혈압의 평균은 남자 120.7±14.7 mmHg, 여자 111.2±12.2 mmHg, 이완기 혈압의 평균은 남자 77.5士10.l mmHg, 여자 71.5±9.5 mmHg였으며, 혈청 총 콜레스테롤은 남자 190.9±38.9 mg/dL, 여자 183.9±39.4 mg/dL였다. PIBW는 남자 107.7±13.0%, 여자 102.6±12.7%였으며, BMI는 남자 23.6±26 ㎏/㎡ 여자 21.4±2.9 ㎏/㎡였다. 수축기 혈압과 이완기 혈압은 남녀 모두 연령이 증가함에 따라 증가하였으나, 총 콜레스테롤, PIBW 및 BMI는 남녀 모두 연령이 증가함에 따라 감소하였다. 총 콜레스테롤은 혈압이 높아짐에 따라 남녀 모두 증가하였으며, 특히 PIBW가 증가함에 따라 매우 유의하게 증가하였다. 남자의 수축기 및 이완기 혈압은 PIBW가 증가함에 따라 매우 유의하게 증가하였으며, 여자는 약간 증가하였다. PIBW와 BNI의 증가에 따른 총 콜레스테롤의 증가가 혈압에 따른 총 콜레스테롤의 증가 보다 매우 유의하게 더 컸다. 가족력은 총 콜레스테롤 및 혈압에 미치는 영향이 적었으며, 음주량은 혈압과 양(positive)의 상관성이 있었으나, 흡연량은 음(negative)의 상관성이 있었다. 위의 결과는 혈청 총 콜레스테롤이 특히 혈압 및 비만과 밀접한 상호 관련성이 있음을 보여주었다. High blood pressure has been associated with elevated atherogenic blood lipid fraction, but epidemiological surveys often give inconsistent results across population subgroups. A better understanding of relation between blood pressure and blood lipids may provide insight into the mechanism whereby hypertension is associated with increased risk of coronary heart disease. We assessed the cross-sectional relations of serum total cholesterol with other health parameters in a population of 5,011 men and 1,171 women 30-69 years old. Measurements of percent ideal body weight (PIBW), body mass index (BMI), blood pressure and cholesterol were made and a questionnaire on family history, smoking, drinking habit was given to each adult subjects. The mean systolic and diastolic blood pressure were 119.0±14.8 mmHg and 76.4±10.2 mmHg, respectively. The mean serum total cholesterol level was 190.9±38.9 mg/dL in men, 183.9±39.4 mg/dL in women, respectively. The systolic and diastolic blood pressure levels increased with age in both sexes, but the levels of serum total cholesterol, PIBW and BMI decreased with age in both sexes. Total cholesterol levels increased significantly with increasing systolic and diastolic blood pressure in both sexes. Total cholesterol levels increased very significantly with increasing PIBW index in both sexes. In men, systolic & diastolic blood pressure levels were very significantly increased with increasing PDBW index, but in women, its increased slightly. The PIBW and BMI index had more influence on the total cholesterol level than blood pressure. Family history had little influence on the cholesterol and blood pressure. Alcohol consumption correlated positively with blood pressure, but cigaretting smoking correlated negatively with blood pressure. These results support the hypothesis that there are biological interrelations between blood pressure and blood lipids that may influence the mechanisms whereby blood pressure is associated with risk of coronary heart disease.

지혈대 압력에 따른 인공 슬관절 치환술 후 발생한 피하출혈양의 관계

김지형 ( Jee Hyoung Kim ),이송 ( Song Lee ),김경태 ( Kyung Tae Kim ),고동오 ( Dong Oh Ko ),양종화 ( Jong Hwa Yang ),이정수 ( Jung Soo Lee ),김대근 ( Dae Geun Kim ) 대한슬관절학회 2011 대한슬관절학회지 Vol.23 No.1

Purpose: We wanted to evaluate the post-operative amount of subcutaneous bleeding according to the tourniquet pressure during total knee replacement. Materials and Methods: We analyzed 136 patients who had undergone total knee replacement at our hospital from March 4th, 2010 to September 16th, 2010. A tourniquet pressure of 250 mm Hg was applied to 69 patients (group I) and a tourniquet pressure of 320 mm Hg was applied to the other 67 patients (group II). Subcutaneous bleeding was evaluated on the 3rd and 6th days after the operations. All of the total knee replacements were performed by a single surgeon. Results: Among the group I patients, subcutaneous bleeding was seen in just 2 patients, yet among the group II patients, there were 32 patients with subcutaneous bleeding on the 3rd day and 33 patients with subcutaneous bleeding on the 6th day. According to the multiple regression analysis, there were no significant differences in ages, the tourniquet time and the orders between the two groups. Group 1 had significantly less subcutaneous bleeding than did group II on the 3rd and 6th days after the operations (p=0.001). Conclusion: There was a significant difference of the amount of subcutaneous bleeding amount according to the tourniquet pressure. We were able to decrease the post-operative amount of subcutaneous bleeding after total knee replacement by lowering the tourniquet pressure to 250 mm Hg.

Significance of operating pressure on process intensification in a distillation with side-reactor configuration

Hussain, Arif,Chaniago, Yus Donald,Riaz, Amjad,Lee, Moonyong Elsevier 2019 Separation and purification technology Vol.213 No.-

<P><B>Abstract</B></P> <P>Distillation with side-reactor (SRC) has already established its potential for understanding the energetic and economic performances of chemical processes. This study assesses the impact of operating pressure on reaction performances and overall economics in the SRC design. In conventional distillation operation, pressure is adjusted such that it permits the use of less expensive cooling water (318 K) in the condenser. However, the pressure of the nonreactive distillation column coupled to a side-reactor should be more carefully managed to obtain the process-intensification potential benefits. In the SRC design, the feed to the side-reactor is withdrawn from the column trays where the reactants are more abundant. Higher column pressure requires a more expensive heat source for the column base and causes temperature rise on the column trays. Depending on the kinetic parameters of the reaction, the pressure of the column can be adjusted to improve the conversion, selectivity, yield, and overall economics of the chemical process in an SRC design. A foremost trade-off between the operating pressure and reactor size/catalyst/heat load is demonstrated through three industrial-chemical processes. The outcome of this study affirmed the importance of understanding the impact, on process intensification, of selecting the appropriate operating pressure during the SRC conceptual design.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The effect of operating pressure on process intensification in SRC design was studied. </LI> <LI> The dependence of side-reactor volume/catalyst weight/heat duty on pressure was studied. </LI> <LI> Three real chemical processes were simulated to analyze the results. </LI> <LI> Optimal design of SRC configurations was obtained by optimizing pressure. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Bent Duct 내부 유동의 손실 측정

노우진(U Jin Roh),임주현(Ju Hyun Im),송성진(Seung Jin Song) 한국추진공학회 2009 한국추진공학회 학술대회논문집 Vol.2009 No.5

Bent duct 는 손실을 가중시키고, 효율을 저하시킨다. 지금까지 bent duct에 대한 많은 연구가 진행되었지만, 입구와 출구가 같은 형상에 대해서 연구가 되어왔다. 이번 연구에서는 입구는 환형이지만, 출구는 원형을 가진 bent duct에 대해서 진행되었다. 입구 속도 54 m/s, 레이놀즈수 238,000에서 수행된 이번 연구에서는 bent duct 바깥에 태핑홀을 배치하여 정압분포를 확인하고, 입구와 출구에서 5공 프로브로 유동을 측정하여 스트림 방향 속도 프로파일과 전압 손실 계수를 얻었다. 본 연구에서는 전압 손실 계수, 0.243를 얻었다. Bent ducts add loss and decrease efficiency. Many researchers have been conducted the performances of bent ducts, but their shapes of inlet and outlet are same. However, in this investigation, the focus is on a bent duct which is annular at the inlet and circular at the outlet. The bent duct of these complex shapes has not been investigated, but has been used in many fields. The performance of such bent duct is investigated under inlet speed 54 m/s and Re = 238,000. Wall static pressure tappings are located surface of the bent duct to measure the static pressure and a probe is traversed at the inlet and outlet of the bent duct to measure the total pressure. As a result, it presents static pressure distribution on the bent duct surface, streamwise velocity profile at inlet and outlet of the bent duct and total pressure loss profile at outlet. In this investigation, the total pressure loss coefficient is 0.243.

이동작동기식 완전 이식형 인공 심장의 심실간 공간 압력 파형 해석에 관한 실험적 연구

조영호,최원우 대한의용생체공학회 1997 의공학회지 Vol.18 No.1

To regulate cardiac output of the Total Artificial Heart(TAH) physiologically, the hemodynamic information must be toed back to the controller. So far, our group has developed an automatic cardiac output control algorithm using the motor current waveform, It is, however difficult to detect the preload level such as a filling status of ventricular inflow and the variation of atrial pressures within normal physiologic range(0-15 mmHg) by analyzing the motor current which simultaneously reflects the afterload effect. On the other hin4 the interventricular volume pressure(IVP) which is not influenced by arterload but by preload is a good information source for the estimation of preload states. In order to find the relationship between preload and IVP waveform, we set up the artificial heart system on the Donovan type mock circulatory system and measured the IVP waveform, right and left atrial pressures, inflow and outflow waveforms and the signals represented the information of moving actuator's position. We shows the feasibility of estimating the hemodynamic changes of inflow by using IVP waveform. fife found that the negative peak value of IVP waveform is linearly related to atrial pressures. And we also found that we could use the time to reach the negative peak in IVP waveform, the time to open outflow valve, the area enclosed IVP waveform as unfu parameters to estimate blood filling volume of diastole ventricle. The suggested method has advantages of avoiding thrombogenesis, bacterial niche formation and increasing longterm reliability of sensor by avoiding direct contact to blood.

Influences of Mach Number and Flow Incidence on Aerodynamic Losses of Steam Turbine Blade

Yoo, Seok-Jae,Ng, Wing Fai Ng The Korean Society of Mechanical Engineers 2000 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.14 No.4

An experiment was conducted to investigate the aerodynamic losses of high pressure steam turbine nozzle (526A) subjected to a large range of incident angles ($-34^{\circ}\;to\;26^{\circ}$) and exit Mach numbers (0.6 and 1.15). Measurements included downstream Pitot probe traverses, upstream total pressure, and end wall static pressures. Flow visualization techniques such as shadowgraph and color oil flow visualization were performed to complement the measured data. When the exit Mach number for nozzles increased from 0.9 to 1.1 the total pressure loss coefficient increased by a factor of 7 as compared to the total pressure losses measured at subsonic conditions ($M_2<0.9$). For the range of incidence tested, the effect of flow incidence on the total pressure losses is less pronounced. Based on the shadowgraphs taken during the experiment, it' s believed that the large increase in losses at transonic conditions is due to strong shock/ boundary layer interaction that may lead to flow separation on the blade suction surface.

대학 보디빌딩 선수의 대사적 수용기 자극에 따른 심혈관 반응

김성민(Kim, Sung-Min),최현민(Choi, Hyun-Min),김종경(Kim, Jong-Kyung),노호성(Nho, Ho-Sung) 한국체육과학회 2012 한국체육과학회지 Vol.21 No.3

Previous studies have shown that resistive exercise training such as isometric handgrip exercise or weight lifting decreases arterial blood pressure. However, the mechanisms responsible for reduction in arterial blood pressure have not been investigated. One mechanism that may lower arterial blood pressure is a neural mechanism termed the muscle metaboreflex that is activated when oxygen delivery to active skeletal muscle falls below a critical level. The muscle metaboreflex, a component of exercise pressor reflex, increases the sympathetic activity to heart and vasculature and then increases arterial blood pressure, cardiac output, and ventilation during exercise. Therefore, the purpose of this study was to investigate the effect of the muscle metaboreflex on hemodynamics following fatiguing rhythmic handgrip exercise and circulatory arrest in 10 male collegiate body builders and 10 age-matched controls. All subjects performed 3 min rhythmic handgrip exercise at the exercise intensity of 60% maximal voluntary contraction and 2 min of postexercise circulatory occlusion while heart rate (HR), stroke volume (SV), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were measured followed by the calculation of cardiac output, mean arterial pressure (MAP), and total vascular conductance (TVC). From resting baseline values, the changes in SBP, DBP, and MAP in body builders during PEI were significantly smaller compared to contol group (SBP: ? 31.2 ㎜Hg vs. ? 36.2 ㎜Hg; DBP: ? 9.9 ㎜Hg vs. ? 18.2 ㎜Hg; MAP: ? 17.0 ㎜Hg vs. ? 24.2 ㎜Hg, respectively). However, there was no difference in CO between two groups (? 2.2 l/min vs. ? 2.2 l/min) and TVC tended to be higher in body builders compared to control group (? 9.0 ml/min/㎜Hg vs. ? 3.9 ml/min/㎜Hg). This study suggest that chronic resistance training may improve the muscle metaboreflex. The mechanism in which the pressor response mediated by the muscle metaboreflex with resistance training is attenuated is due to peripheral vasodilation.

압력면익단소익이 터빈 동익 압력면스퀼러팁 하류의 팁누설유동 및 압력손실에 미치는 영향

천주홍(Joo Hong Cheon),이상우(Sang Woo Lee) 대한기계학회 2016 大韓機械學會論文集B Vol.40 No.10

본 연구에서는 압력면익단소익의 폭이 터빈 동익 압력면스퀼러팁 하류의 팁누설유동 및 압력손실에 미치는 영향에 대하여 연구하였다. 팁간극비 h/s = 1.36%에 대하여, 흡입면스퀼러의 높이는 hp/s = 3.75%로 일정하게 유지하고, 압력면익단소익의 폭은 w/p = 2.64%, 5.28%, 7.92%, 10.55% 등으로 변화시키면서 실험을 수행하였다. 일반적으로 압력면익단소익의 폭이 증가할수록, 통로와류 영역에서의 압력손실은 감소하였지만 팁누설유동 영역에서는 압력손실이 오히려 증가하였다. 그 결과 익단소익의 폭이 증가할수록, 질량평균 압력손실은 매우 소폭 감소하는 경향을 보였다. 본 연구 결과, 압력면스퀼러팁에 설치된 압력면익단소익은 압력손실 저감에 거의 기여를 하지 못함을 확인할 수 있었다. Effects of pressure-side winglet width on the tip leakage flow and aerodynamic loss downstream of a turbine blade with a pressure-side squealer rim have been investigated for the tip gap-to-span ratio of h/s = 1.36%. The pressure-side squealer has a fixed height-to-span ratio of hp/s = 3.75% and the pressure-side winglet, which is installed at an elevation of tip surface, has width-to-pitch ratios of w/p = 2.64%, 5.28%, 7.92% and 10.55%. The results show that with increasing w/p, aerodynamic loss in the passage vortex region decreases, whereas that in the leakage flow region increases. As a result, the mass-averaged loss coefficient all over the measurement plane tends to decrease minutely with the increment of w/p. It is concluded that the pressure-side winglet for the pressure-side squealer tip can hardly contribute to the tip-leakge loss reduction.

Projection of the rotation form Navier-Stokes equation onto the half-staggered grid

Ji Ryong Cho 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.7

A projection method for computing incompressible fluid flow is proposed. For the method, the rotation form Navier-Stokes equation (NSE), for which the velocity and the total pressure are employed, is discretized on the half-staggered, finite difference spatial grid. The total pressure couples the static pressure gradient and the convection of momentum in the continuous NSE while the half-staggered grid provides weak pressure-velocity coupling in discrete space. These two features interact synergistically for the discretized NSE to produce smooth pressure fields without additional numerical artifacts such as the momentum interpolation. The method preserves the kinetic energy at the inviscid limit condition. Numerical solutions of the decaying Taylor vortex, the inviscid Taylor vortex, the sudden expansion channel and the square-prism wake are presented.

흐름과 파에 의한 해저지반내 간극수압의 발생과 액상화에 관한 해석적인 연구

이광호(Kwang-Ho Lee),김동욱(Dong-Wook Kim),김도삼(Do-Sam Kim),배기성(Ki-Seong Bae),전종혁(Jong-Hyeok Jeon) 한국해안해양공학회 2015 한국해안해양공학회 논문집 Vol.27 No.5

진행파 혹은 임의 반사율을 갖는 부분중복파 혹은 완전중복파-흐름-해저지반의 상호작용에 관한 해석해가 Lee et al.(2014; 2015a; 2015b; 2015c; 2015d) 및 Yamamoto et al.(1978)과 같은 다수의 연구자들에 의해 유도되었으며, 그들은 진동간극수압과 잔류간극수압을 별개로 취급하여 각 파동에 의한 지반응답을 논의하였다. 그러나, 실제 현장이나 실험에서 해저지반내 간극수압은 진동성분과 잔류성분이 별개로 나타나는 것이 아니고 그의 합 (전간극수압)으로 주어지기 때문에 전간극수압의 관점에서 반드시 검토될 필요가 있다. 따라서, 본 연구에서는 진동간극수압과 잔류간극수압뿐만 아니라 전간극수압의 측면에서 파동조건, 지반조건 및 흐름조건의 변화에 따른 지반응답의 변동특성을 논의하였으며, 더불어 이에 따른 액상화의 연직깊이에서 특성변화를 검토하였다. 이로부터 진행파와 순방향의 흐름의 공존장에서는 흐름속도가 증가할수록 무차원진동간극수압이 증가하고, 무차원잔류간극수압은 감소하여 결과적으로 무차원전간극수압이 작아지며, 무차원액상화 깊이도 감소하는 등의 지반응답특성을 확인할 수 있었다. Analytical solutions for interaction between seabed and waves such as progressive wave or partial standing wave with arbitrary reflection ratio or standing wave have been developed by many researchers including Lee et al.(2014; 2015a; 2015b; 2015c; 2015d) and Yamamoto et al.(1978). They handled the pore-water pressure as oscillating pore-water pressure and residual pore-water pressure separately and discussed the seabed response on each pore-water pressure. However, based on field observations and laboratory experiments, the oscillating and residual pore-water pressures in the seabed do occur not separately but together at the same time. Therefore, the pore-water pressure should be investigated from a total pore-water pressure point of view. Thus, in this paper, the wave-induced seabed response including liquefaction depth was discussed among oscillating, residual, and total pore-water pressures’ point of view according to the variation of wave, seabed, and flow conditions. From the results, in the field of flow with the same direction of progressive wave, the following seabed response has been identified; with increase of flow velocity, the dimensionless oscillating pore-water pressure increases, but the dimensionless residual pore-water pressure decreases, and consequently the dimensionless total pore-water pressure and the dimensionless liquefaction depth decrease.