• Journal of Biomedical Engineering Research
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• v.17 no.1
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• pp.43-48
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• 1996

We investigated the energistics of the physiological heart model by comparing predictive indexes of the myocardial oxygen consumption (MOC), such as tension-time index (R), tension-time or force-time inteual (FTI), rate-pressure product (RPP), pressure-work index, and systolic pressure-volume area (PVA) when using the electro-hydraulic left ventricular device (LVAD). We developed the model of LVAD incorporated the closed-loop cardiovascular system with a baroreceptor which can control heart rate and time-varying elastance of left and right ventricles. On considering the benefit of the LVAD, the effects of various operation modes, especially timing of assistance, were evaluated using this coupled computer model. Overall results of the computer simulation shows that our LVAD can unload the ischemic (less contractile) heart by decreasing the MU and increasing coronary flow. Because the pump ejection at the end diastolic phase of the natural heart may increase the afterload of the left ventricle, the control scheme of our LVAD must prohibit ejecting at this time. Since the increment of coronary flow is proportional to the peak aortic pressure after ventricle contraction, the LVAD must eject immediately following the closure of the aortic valve to increase oxygen availability.

• Environmental Analysis Health and Toxicology
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• v.18 no.4
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• pp.295-303
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• 2003

Physiological cellular activities responses to cadmium (Cd) exposure in green algae with several reductases activities and viability of the cell were examined. The cell division of green algae, Selenastrum capricornutum treated with 5ppm was significantly decreased than that of normal algae. The mean cell number of normal algal culture was as twice much as than that of algae at 6 days after Cd treatment. The cellular viability of algae was analysed by flow-cytometry with fluorescent dye after esterase reaction on cell membrane. The 85.35% of cellular viability of normal culture was decreased to 34.35% when algae was treated with 5 ppm of Cd at 6 days after treatment. It was considered that those method of flow-cytometry is useful tool for toxicity test on micro-organisms in the respect of identifying cellular viability. Also, the activities of both glutathione peroxidase (GPX) and ascorbate peroxidase (APX), which are indirectly react against oxidative stress through reduction of glutathione by Cd were significantly increased with 25%. It is considered that both GPX and APX are involved in the metabolic pathway of Cd -detoxification with similar portion in Selenasturm capricornutum.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.168-174
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• 2009

High water vapour content in air can cause a number of problems as for human or surrounding materials. For human a high water vapour can create physiological stress, discomfort, and also can encourage ill health. While, the cause for the environment is can accelerate the corrosion of metals, accelerate the growth of spores and mould, can reduce the electrical resistance of insulators and etc. Desiccant systems have been proposed as energy saving alternatives to vapor compression air conditioning for handling especially the latent load and also sensible load. Use of liquid desiccants offers several design and performance advantages over solid desiccants, especially when solar energy is used for regeneration. The liquid desiccants contact the gas inside the packed tower of liquid desiccant solar cooling system and the heat transfer and mass transfer will occur. This thesis is trying to study the characteristics inside the packed tower of dehumidifier systems. This characteristics consist of mass transfer rate, heat transfers rate, human comfort and energy that consume by the system. Those characteristics were affected by air flow rates, air temperature and humidity, and desiccant temperature and all that variation will influence the performance of the systems. The results of this thesis later on can be used to determine the best performance of the systems.

• The Korean Journal of Physiology
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• v.22 no.1
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• pp.41-53
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• 1988

The present study was undertaken to clarify the involvement of atrial natriuretic peptide in the development of hypertension in spontaneously hypertensive rats. Plasma concentration of immunoreactive atrial natriuretic peptide was higher in spontaneously hypertensive rats than in normotensive Sprague-Dawley and Wistar rats. Plasma renin concentration was lower in SHR than in normotensive rats, as observed in earlier experiments. Hydration-induced increase in urine flow and urinary excretions of sodium and potassium were smaller in SHR than in normotensive control rats. Intraarterial infusion of atrial natriuretic peptide resulted in increases in urine flow, urinary excretions of sodium and potassium in both hypertensive and normotensive rats. Renal response to atrial natriuretic peptide was markedly suppressed in SHR. Plasma renin and aldosterone concentration were suppressed by atrial natriuretic peptide in both SHR and normotensive rats. The responses were not significantly different in both groups. These results suggest that the renal responsiveness to atrial natriuretic peptide may be suppressed in SHR by some mechanisms still remaining obscure.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.4
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• pp.1013-1018
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• 2003

Cheonghunhwadam-tang(CHT) have been used in oriental medicine for many centuries as a therapeutic agent of vertigo by wind, fire and phlegm. CTG was CHT adding Aurantii FructusㆍGastrodae Rhizoma. CTG was significantly increased regional cerebral blood f1ow(rCBF) in a dose-dependent, and CTG was decreased mean arterial blood pressure(MABP) compared with normal MABP(100%) in a low dosage, but was increased MABP in a dose-dependent, was aliked with normal MABP in a high-dosage. Therefore, purpose of this Study was to investigate experimental mechanism of CHTAG on the cerebral hemodynamics(rCBF, MABP) in rats. The changes of rCBF and MABP were determinated by Laser-Doppler Flowmetry(LDF). The results were as follows ; Pretreatment with indomethacin(3㎎/㎏, i.v.) was significantly inhibited CTG induced increase of rCBF and pretreated with propranolol(3㎎/㎏, i.v.) was inhibited CTG induced increase of rCBF, but pretreatment with methylene blue(10㎍/㎏, i.v) was increased CTG induced increase of rCBF. Pretreatment with indomethacin was decreased CTG induced increase of MABP, but pretreatment with propranolol and methylene blue were increased CTG induced increase of MABP. This results suggest that the mechanism of CTG is mediated by cyclooxygenase.

• Journal of Lipid and Atherosclerosis
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• v.7 no.2
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• pp.88-97
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• 2018

The prevalence of atherothrombotic disease continues to rise, presenting an increasing number of challenges to modern society and creating interest in functional foods. Platelet activation, adhesion, and aggregation at vascular endothelial disruption sites are key events in atherothrombotic disease. Physiological challenges such as hyperlipidemia, obesity, and cigarette smoking are associated with vascular changes underlying platelet aggregation and inflammatory processes. However, it is difficult to determine the beneficial response of functional foods in healthy subjects. To address this problem, challenge models and high-risk models related to smokers, obesity, and dyslipidemia are proposed as sensitive measures to evaluate the effects of functional foods in healthy subjects. In this review, we construct a model to evaluate the effects of functional food such as natural products on blood flow based on a human intervention study.

• BioChip Journal
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• v.12 no.4
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• pp.257-267
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• 2018

Inertial microfluidics has attracted significant attention in recent years due to its superior benefits of high throughput, precise control, simplicity, and low cost. Many inertial microfluidic applications have been demonstrated for physiological sample processing, clinical diagnostics, and environmental monitoring and cleanup. In this review, we discuss the fundamental mechanisms and principles of inertial migration and Dean flow, which are the basis of inertial microfluidics, and provide basic scaling laws for designing the inertial microfluidic devices. This will allow end-users with diverse backgrounds to more easily take advantage of the inertial microfluidic technologies in a wide range of applications. A variety of recent applications are also classified according to the structure of the microchannel: straight channels and curved channels. Finally, several future perspectives of employing fluid inertia in microfluidic-based cell sorting are discussed. Inertial microfluidics is still expected to be promising in the near future with more novel designs using various shapes of cross section, sheath flows with different viscosities, or technologies that target micron and submicron bioparticles.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.4
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• pp.269-282
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• 2017

Objectives: Currently, masks against yellow dust and fine particulates are being certified with no consideration of facial dimensional variations among children and adults. The aims of this study were to develop masks against yellow dust and fine particulates for children in Korea and provide basic data to suggest new test methods for mask certification that consider the breathing capacity of children. Methods: A total of 730 study participants aged from six to 13 years old were recruited in the Seoul, Gyeonggi, and Incheon region. This study used a 3D scanning instrument to obtain 16 facial anthropometric data points. Literature reviews, a comparison of breathing capacity between adults and children, and analysis of children's pulmonary physiological data were conducted in order to suggest new test standards for certifying children's masks against yellow dust and fine particulates. In addition, types of children's masks, choice of wearing a mask or not, and reasons for not wearing masks were surveyed. Results: Based on a clustering analysis of participants' facial dimensions, facial shapes were classified into three groups: small, medium, and large. The sizes of children's masks were subtracted by using 3D sketch techniques(Large: $121.25mm{\times}89.46mm$, Medium: $111.92mm{\times}78.55mm$, Small: $102.13mm{\times}72.87mm$). In certifying children's mask, flow rates of $60{\ell}/m$ for the filtering efficiency test and $20{\ell}/m$ for the breathing resistance test were recommended, since children's pulmonary physiological capacity is about 60-70% of adults' pulmonary capacity. Conclusions: The results of this study suggest that three mask sizes for children would be sufficient and practical for providing protection against yellow dust and fine particulates. Revising current test methods for certifying respiratory protective devices for children is important, since children's pulmonary physiological capacity substantially differs from that of adults. Therefore, it is recommended that new test standards for certifying children's masks be promulgated in the near future.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.6
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• pp.1513-1520
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• 2009

The purpose of this study was to compare cerebral blood flow between hyperlipidemic patient group and normal healthy aldult group using transcranial doppler ultrasonography(TCD). I investigated cerebral blood flow of 63 hyperlipidemic patients and 42 healthy adults. To evaluate the cerebral blood flow, I measured the systolic peak velocity(Vs) and mean flow velocity(Vm) of the milddle cerebral artery(MCA), anterior cerebral artery(ACA), posterior cerebral artery(PCA), basilar artery(BA), internal carotid artery(ICA) in the two groups using TCD. In normal healthy adults, subjects showed a decerease in Vs and Vm with advancing in age. There was a significant difference in the Vm of ICA. There was no significant differences in the Vm of ACA and ICA. In normal healthy adults, females showed high velocities of all examined vessel. There was a significant difference in the Vs of ICA. There was a significant differences in the Vm of MCA and ICA. Normal healthy adults higher than hyperlipidemic patients in the Vs of MCA, ACA, PCA. There was no significant difference in the Vs of all exmined vessels. Hyperlipidemic patientsincrease higher than normal healthy adults in the Vm of ACA. There was a significant difference in the Vs of BA. In the patients aged under 50's, normal healthy adults higher than hyperlipidemic patients in the Vs and Vm except BA. But there was no significant difference in all exmined vessels. In the patients aged over 50's, hyperlipidemic patients higher than normal healthy adults in all examined vessel expect PCA. There was a significant difference in the Vs of BA and ICA. And hyperlipidemic patients higher than that normal healthy adults in all exmined vessels. There was a significant difference in BA and ICA. In this study, visible differences in blood flow between hyperlipidemic patient group and normal healthy aldult group were shown. However, these results do not come up to the previous values that were reported and known worldwide.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.6
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• pp.1431-1441
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• 2006

Following conclusions were drawn from the examination of the usage of semen persicae and fols carthami from the view of Hyungsang Medicine. Semen persicae is used to vitalize the blood flow and eliminate the blood stagnation of the whole body in ${\ulcorner}$Donguibogam${\lrcorner}$, and therefor it is used for the blood flow of the heptal meridian and sometimes the intestinal meridian. Flos carthami is applied to vitalize the blood flow, remove obstructions in meridians, eliminate the blood stagnations, and stop the pain in ${\ulcorner}$Donguibogam${\lrcorner}$, therefore used in such symptoms of blood flow of the heptal meridian as amenorrhea, spasm of muscles, and coldness of the genitals. Also is applied in those cases of exhaustion, perspiration, and in digestive remedies which belong to the symptoms of cardiac blood flow. And it is used for dryness of the skin in which case the blood should be developed and malaria for the elimination of the blood stagnation and production of new blood. The combination of semen persicae and flos carthami is applied to eliminate the blood stagnation and stimulate menstrual discharge in uterus, as well as in the cases of lumbago and stomachache due to blood stagnation, blood stasis, mass in the abdomen, and abdominal distention. This combination is also used for the eyes, ears, numbness, and paralysis of hands and feet for the purpose of making the flow of the meridian smooth, and for diabetes, dryness of the skin, malaria, anal itching and pain for the purpose of eliminating the mass and renewing the tissues. The combination is diversly used in the book of ${\ulcorner}$Special lectures on clinical cases${\lrcorner}$ for the aftereffects of traffic accident, constipation, diabetes, dryness of the skin, paralysis of hands and feet, numbness of finger of hand and foot, and especially used frequently with prescription of Yijintang and Samultang combined in the cases of numbness. The prescription is used in Hyungsang medicine when the uterus, the external appearance(axis), hands and feet, heart, and the stomach is not good for the vitalization of the flow of the 12 meridians. It was though difficult to find extinguishing differences between the two herbs in the clinical cases applied in the book of ${\ulcorner}$Special lectures on clinical cases${\lrcorner}$.