• The Korean Journal of Physiology and Pharmacology
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• v.6 no.3
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• pp.149-154
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• 2002

The blood pressure (BP) is regulated by the nervous system and humoral factors, such as renin- angiotensin system, vasopressin and others. In the present study, we examined the central effects of glutamate and GABA on the cardiovascular regulation by injection of these substances into the lateral ventricle and also investigated the relationship between these central effects and the action of angiotensin II (Ang). Male Sprague Dawley rats, $350{\sim}400$ g, were anesthetized with urethane and instrumented with an arterial catheter for direct measurement of BP and heart rate (HR), and an guide cannula in the lateral ventricle for drug injection. A glass microelectode was inserted into the rostral ventrolateral medulla (RVLM) for recording single unit spikes. Barosensitive neurons were identified by changes of single unit spikes in RVLM following intravenous injection of nitroprusside and phenylephrine. The effects of GABA and glutamate injected into the lateral ventricle were studied in single neuronal activity of the RVLM in addition to changes in BP and heart rate, and compared the results before and after treatment with intravenous losartan, nonpeptide Ang II-type 1 receptor antagonist (1 mg/100 g BW). Intracerebroventricular administration of GABA decreased systolic blood pressure (SBP) and HR, but increased the firing rates in the RVLM. However, intracerebroventricular glutamate injection produced effects opposite to GABA. After pretreatment of intravenous losartan, the central effects of GABA on BP and firing rate in the RVLM were significantly attenuated and that of glutamate showed a tendency of attenuation. These results suggested that central GABA and glutamate regulated BP and firing rates in RVLM were inversely related to BP change. The central effects of GABA or glutamate on the autonomic nervous function were modulated by humoral factor, Ang II, by maintaining BP.

• Korean Journal of Social Welfare
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• v.42
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• pp.397-422
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• 2000

Since 1998 when economic assistance from IMF started, the empirical research on the effects of unemployment and drastic income loss on psychological functioning among the unemployed as well as their family members has increased. These studies have found that unemployment and drastic income loss following unemployment have significant negative influence on the psychological outcomes such as anxiety and depression of the unemployed and their family members. Studies have also focused on the role of social support in this process, and reported that depending on the levels of received social support, unemployment and income loss have differential effects on the psychological aspects of the unemployed. However, these studies have several weaknesses. First, most of the related studies employed the data which were collected from limited regions of the country, which imposes limitations on the scope of the generalizability of research findings. Second, the main independent variables used in these studies were mainly unemployment or income loss, which ignore the psychological evaluation by the employed of their family financial situations. Third, in analyzing the moderating effects of social support, most studies have focused mainly on showing the existence of moderating effects by social support. Consequently, the nature and role of social support remained unanalyzed and left to speculations. The purpose, of this study is to examine the effects of economic pressure experienced by family heads who were unemployed and to analyze the moderating role of social support based on a nationally representative sample. The findings showed that economic pressure has negative influence on anxiety and depressive feelings among the unemployed, and that the effect of economic pressure on depressive feelings were substantially higher among those who have received lower levels of social support from family members than that among those with higher levels of family support.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.11
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• pp.1458-1465
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• 1997

This study investigated the effects of pressure on the growth of an impinging spray. We obtained the frozen images which were scattered by Nd ; YAG laser light (pulse width : 7 ns) using synchronization circuit made in the laboratory. For an impinging spray a growth of the penetration length was progressed with increase of the injection pressure but an ambient pressure restrained its growth. The effect of an ambient pressure on penetration was larger than that of an injection pressure. The pressure ratio had an effect on the penetration growth rate. The thickness growth rate depended on both the injection pressure and the ambient pressure compositively. A lower injection pressure or a higher ambient pressure was required for spatial distribution of impinging spray.

• Journal of Environmental Health Sciences
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• v.38 no.4
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• pp.311-322
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• 2012

Objective: The effect of lead on blood pressure remains controversial in spite of the numerous studies which have been conducted in the recent years. The aim of this study was to evaluate the effects of exposure to lead on blood pressure among non-smokers. Methods: In this cross sectional study, 1416 male and female non-smokers were enrolled, aged 20 years or older, from the Korean National Health and Nutrition Examination Survey 2008. Blood pressure, blood lead levels (BLLs), height, weight, and cotinine level were measured for all subjects. Results: Geometric mean BLLs of the participants was 2.20 ${\mu}g$/dl. BLLs were higher in the older, male, and lower education groups than the younger, female and higher education groups. After adjusting for age, sex, education and BMI through multiple regression analysis, a significant positive association between systolic blood pressure (p = 0.0357), diastolic blood pressure (p = 0.0111) and BLLs. Also, among the normal BMI group (18.5 kg/$m^2$ < BMI < 25 kg/$m^2$), we also found a significant positive association between diastolic blood pressure and BLLs (p = 0.0370). Conclusion: The present study showed that blood lead serves as a good predictor of blood pressure changes and that there was a statistically significant association between blood lead and blood pressure, especially diastolic blood pressure.

• Journal of the Ergonomics Society of Korea
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• v.29 no.6
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• pp.875-887
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• 2010

The quantitative effectiveness of powered support surfaces such as APAM in preventing and treating pressure ulcers has not been sufficiently evaluated because of uncertainty of alternating pressure load input and lack of interpretation of dynamic perfusion characteristics of soft tissue. The aim was to verify the dynamic loading effects to sacral tissue perfusion characteristics from alternating set pressure changes. We developed integrated experiment system to supply alternating load to supinely positioned sacrum and concurrently measured $TcPO_2$, $TcPCO_2$ and air cell pressure. Ten aged subjects (5 female, 5 male) were tested with alternating set pressure 20, 30, 40, 50 and 60mmHg. From the dynamic perfusion response eight characteristic parameters were proposed such as average, minimum, maximum and perfusion range regarding to $TcPO_2$ and $TcPCO_2$. A one-way ANOVA was carried out to determine whether the manipulation of alternating set pressure had any effect on $TcPO_2$ and $TcPCO_2$. From the dynamic tissue perfusion response we found mean $TcPO_2$ decreased exponentially as alternating pressure load increased and perfusion range varied mainly because of minimum level change of $TcPO_2$. And perfusion range of $TcPCO_2$ affected by increase of maximum value of $TcPCO_2$. From the results we can get more strict insights about actual physiological dynamic tissue perfusion mechanism under alternating pressure load.

• Korean Journal of Pharmacognosy
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• v.48 no.2
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• pp.97-107
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• 2017

There is no doubt that the effect of ginseng on blood pressure could be different depending upon the type of ginseng employed for the experiment and methodology, thereby can exert bilateral modulatory activity on blood pressure. It has been reported that ginseng induced no significant change in blood pressure in those subjects with normal blood pressure, but had a normalizing effect on the subjects with abnormal blood pressure. Especially, experimental evidence indicates that ginsenoside Rg3, a major component of red ginseng, has been found to lower blood pressure, which is mediated by release of endothelium-derived NO, enhancing the accumulation of cGMP in the rat aorta. This clinical results further support the beneficial effect of Korean ginseng on blood pressure elucidated by animal experiment. As expected, a multicentric non-controlled clinical study shows that the effect of ginseng consumption has been found to normalize blood pressure in hypertensive or hypotensive individuals as compared to virtually no effect in normotensives. In addition, ginseng has been known to exhibit blood pressure decreased with no significant side effect and deteriorated QOL during the combination therapy of ginseng and anti-hypertensive drugs. This review provides a comprehensive overview on the effects of Korean ginseng on blood pressure.

• The Journal of Internal Korean Medicine
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• v.17 no.1
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• pp.290-299
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• 1996

The purpose of this research was to investigate the effects of water extract of Mockhyangjokisan on the blood pressure in rabbits The following results have been obtained : 1. The drug significantly increased arteral blood pressure in rabbits. 2. The drug did'nt effect the increase of arteral blood pressure by pretreated atropine and propranolol in rabbits. 3. The drug inhibited the increase of arteral blood pressure by pretreated regitine in rabbits.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.967-968
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• 2010

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.267-272
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• 2000

The modeling on uplift pressure on the foundation of a dam on which it was constructed, and on the interface between the dam and foundation is a critical aspect in the analysis of concrete gravity dams. The evaluation of stress intensity factor at the crack tip of concrete gravity dam due to uplift pressure effect by surface integral method is performed in this study. The effects of body force, overtopping pressure and water pressure on the crack-face are also considered in this study.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1221-1225
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• 2008

In this paper, analysis of pressure and flow characteristics have been performed with a servo valve. A number of servo valve have been used in various applications including the inserting device, bearing transportation and welding machine. By analysis of flow and pressure gradient, technology can be obtained about optimal simulation of high response servo valve for competitiveness. Spool displacement and ratio of inlet/outlet pressure can give big effects to flow and pressure inside servo valve.