• Journal of Nutrition and Health
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• 제32권6호
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• pp.671-680
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• 1999

In order to investigate the relationship between plasma renin activity and metabolism of Ca and Na in blood pressure, the habitual dietary intakes of Na and Ca urinary excretion of Ca, Na and K, and plasma level of renin activity, aldosterone, and indices of Ca metabolism were measured in 27 untreated hypertensive women and 30 age-matched normal women on a free diet. Hypertensive subjects were classified into high renin hypertensive (HH), medium renin hypertensive(HM) and low renin showed no significant difference among normotensive, LH, MH and HM groups. It appeared that 25-(OH) Vit D3 level of HH group was significantly higher than LH group(p<0.05). There was significant difference in habitual intake of Ca between normotensive and LH groups. However, habitual intake of Na showed no significant difference among normotensive, LH, MH and HH group. Positive correlation of systolic and diastolic blood pressure with PTH(r=0.324, r=0.375) and urinary Ca(r=0.496, r=0.278) and a negative correlation of systolic blood pressure with habitual Ca intake(r=-0.371) existed(p<0.05). A relative magnitude of factors affecting hypertension was analyzed by multiple regression analysis. Overall results about relative influence of independent variables to dependent variable (systolic blood pressure) indicated that urinary Ca was the higher correlation in all subjects(p<0.0001), followed by age and aldosterone. PTH showed a significant correlation for relative influence on diastolic blood pressure in all subjects. The above results indicated that renin-aldosterone system and Ca regulating hormone had a mutual relationship in hypertension.

• Tribology and Lubricants
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• 제30권5호
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• pp.284-290
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• 2014

The influence of round embossed surface on slider bearing characteristics and its load carrying capacity is discussed for thin film effect of embossed slider bearing. For the numerical computation of lubrication parameters such as pressure, load capacity and shear stress that are normalized and a Reynolds equation is used for the analysis of embossed slider bearing characteristics. For this purpose, the finite difference method of central difference scheme is used in this study. In a slider bearing with embossed form, several simulation parameters such as pressure, load capacity and shear stress of the bearing can be obtained according to independent parameters such as the slope of the slider bearing and number of embossing in the upper slider. Also this results can be summarized and be stored in sequential data file for latter analysis. After all, their distribution of the pressure and shear stress parameters can be displayed and be analyzed easily by using the developed program with matlab GUI technique. The independent parameters such as a number of embossing and a slope of the embossed surface slider are used for discussing simulation parameters of pressure distribution, shear stress and load carrying capacity of the round embossing. These study results reported in this paper should be applied to the other shaped slider bearing with a rectangular embossed surface or rectangular waved surface.

• 성인간호학회지
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• 제17권3호
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• pp.349-357
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• 2005

Purpose: This study was conducted to evaluate the effects of foot reflexologic massage on blood pressure and sleep of elderly with essential hypertension. Method: This study was employed non-equivalent control group pretest-posttest quasi-experimental design. The subjects were divided into two groups: 20 elders for experimental group and 18 elders for control group. For experimental group, foot reflexologic massage was done three times at three-day intervals. The data analyzed by SPSS version 10.0 program. Result: The systolic and diastolic blood pressure after foot reflexologic massage did not show a significant difference between the two groups. In experimental group, there was a significant difference in the systolic(t=3.559, p=.001) and the diastolic blood pressure(t= 3.048, p=.004) that measured after foot reflexologic massage. There was a significant difference(t=2.665, p=.011) in sleep between the two groups. Conclusions: The results suggest that foot reflexologic massage was partially effective to reduce the degree of blood pressure and improve sleep of the elderly with essential hypertension. A follow up research is needed to compare and confirm its long-term effects.

• Tribology and Lubricants
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• 제32권5호
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• pp.166-171
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• 2016

Electric vehicle ownership is expanding for two reasons: its technology features have enhanced fuel economy, and the number of vehicle emissions regulations is increasing. Battery performance has a large influence on the capability of electric vehicles, and even though battery thermal management has been actively researched, specific technological improvements to battery performance are not being presented. For instance, many industrial applications utilize vortex tubes as components for refrigeration machines because of their numerous intrinsic benefits. If electric vehicles incorporate vortex tubes for battery cooling, performance and efficiency advancements are possible. This study uses a counter-flow vortex tube to investigate its temperature separation characteristics, based on the back pressure of the cold air exit and the difference between the inlet and back pressures. The experiment uses a vortex tube with the following parameters: six nozzle holes, a 20 mm inner vortex diameter (D), a 14D tube length, a 0.7D cold exit orifice diameter, and a nozzle area ratio of 0.142. The measurements prove that the temperature difference between the hot air and cold air decreased because of the flow resistance of the hot air and the backflow phenomenon at the cold air exit. The flow resistance causes the temperature difference to decrease, and the back pressure of the cold air exit influences the flow resistance. The results show that the back pressure significantly influences the efficiency of temperature separation.

• 설비공학논문집
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• 제25권10호
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• pp.562-567
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• 2013

1D-numerical analysis of the network algorithm with the orifice equation for the relationship between pressure difference and flowrate has been mostly used to analyse leakage flow at the gap. In this study, a 3D-numerical method applying momentum loss model to the gap region in the computational domain is represented to reflect effectively the effect of leakage flow by determining the proportion of pressure difference to air passage velocity. While the 3D-numerical method is verified through the computation of the two compartments model, the numerical analysis of the stack effect in a building stairway is performed. As the temperature of air outside drops, the pressure in the upper stairway and leakage flowrate through the gap in the door rise. The change of gap area does not have an effect on pressure in the stairway for the analysis conditions.

• 대한물리의학회지
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• 제18권1호
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• pp.59-66
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• 2023

PURPOSE: This study examined the foot pressure distribution using the sprinter and skater patterns of coordinative locomotor training. METHODS: Thirty healthy adults, comprising 11 men and 19 women, participated in the study. All the participants performed patterns in sprinter pattern conditions 1-3 and skater pattern conditions 1-3, and were measured using a pedoscan to determine the applied foot pressure distribution. RESULTS: The participants significantly differed in the big toe during the sprinter pattern. As a result of the post hoc test, opposite and opposite sprinters showed a significant difference from the same sprinters (same sprinter; 21.33 ± 5.92, opposite sprinter; 23.54 ± 5.41, and reopposite sprinter; 24.14 ± 6.46). There was a significant difference in the lateral side during the skater pattern. As a result of the post hoc test, reopposite and same skaters showed a significant difference from opposite skaters (same skater; 49.88 ± 5.75, opposite skater; 48.78 ± 5.64, and reopposite skater; 51.15 ± 5.37). CONCLUSION: The foot pressure was distributed toward the hallux and fifth toe according to the sprinter and skater patterns of coordinative locomotor training.

• 운동영양학회지
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• 제14권2호
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• pp.95-101
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• 2010

The purpose of this study was to evaluate changes of body composition, cardio-respiratory function in ventilation threshold (VT) and maximal state exercise, systolic (SBP) and diastolic blood pressure (DBP) and serum nitric oxide (NO) production during acute reducing salt (RS) supplementation in college elite athletes. Variables of cardio-respiratory function during rest, ventilation threshold and maximal exercise was not shown a significantly difference between RS supplementation and non-supplementation, there was shown a significant increase in ventilation threshold time (p<0.05) and exhaustion time (p<0.05) during RS supplement compared to non-supplement. SBP and DBP were not shown a significant difference between RS supplement and non-supplement. This result suggests that acute intake of RS is not increased a blood pressure. Serum NO production was not significant difference in the RS supplement group, but it was shown a significantly increased levels (p<0.01, vs. recovery 30 min.) immediately after maximal exercise in the non-supplement group. This result suggests that acute intake of RS have important role in inhibition of serum NO production during maximal exercise. Conclusively, This study suggest that acute intake of RS was not influence in body composition variables, but it was positive effect in ventilation threshold time, exhaustion time, maintenance of blood pressure and inhibition of serum NO production in maximal treadmill exercise.

• 대한통합의학회지
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• 제4권1호
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• pp.31-39
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• 2016

Purpose : The purpose of this study was to investigate the effects of flexibility and foot pressure on stretching exercise of hamstring muscle with and without pelvis neutral position. Methods : This study was performed on 30 subjects. Thirty subjects were divided into two group; hamstring passive stretching exercise with pelvis neutral position(n=15), hamstring passive stretching exercise without pelvis neutral position(n=15). Both of the group performed the exercise 4 times a week for 6 weeks. The data was analyzed by the paired t-test for comparing before and after changes of factors in each group and the independent t-test for comparing the between groups. Results : The results were as follows. There was statistically significant difference of before and after hamstring flexibility, foot pressure in pelvis neutral position(p<0.05). There was statistically significant difference of before and after hamstring flexibility, foot pressure without pelvis neutral position group(p<0.05). There was no statistically significant difference of between the two group in hamstring flexibility, foot pressure(p>0.05). Conclusion : As a result of this study, though no statistically significant difference of the between groups, we suggest that stretching exercise of hamstring muscle with pelvic neutral may be effective more than stretching exercise of hamstring muscle without pelvic neutral in flexibility, foot pressure.

• 한국한의학연구원논문집
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• 제18권3호
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• pp.111-118
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• 2012

Objective : The aim of this study was to investigate the number of measurements and visits for blood pressure measurement. We also analyzed the change of blood pressure based on the measurement method and measurement interval. Methods : Data of three clinical trials evaluating the effect of acupuncture, moxibustion, and qigong for pre and mild essential hypertension were used. Blood pressure was measured 3 times each visit with 1 or 5 minutes interval, and it was checked until $3^{rd}$ visit. Two trials used sphygmomanometer and another one trial used automatic device for blood pressure measurement. Results : The mean difference between $1^{st}$ and $2^{nd}$, and $2^{nd}$ and $3^{rd}$ measurement were significant in systolic (p<0.001) and diastolic blood pressure (p<0.001). However, in automated measurement or measuring with 1 minute interval, the difference between $2^{nd}$ and $3^{rd}$ was not significant. The mean of $1^{st}$ and $2^{nd}$ measurements was also significantly different from the mean of all three measurements in both systolic (p<0.001) and diastolic blood pressure (p<0.001). While the difference between each visit was not significant in diastolic blood pressure, the systolic blood pressure difference was significant between $1^{st}$ and $2^{nd}$ visit in automated and manual measurement. Conclusion : The mean of two measurements and three measurements were significantly different. The change of blood pressure was different according to the method and interval of blood pressure measurement.

• 한국운동역학회지
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• 제23권1호
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• pp.25-35
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• 2013

This study examined 24 right-handed amateur baseball players. Twelve who had played baseball for more than 6 years were grouped as skilled players, while 12 who had played for 1-3 years were the unskilled player group. The swing motion was divided into four event phases: stance, backswing, impact, and follow-through. The mean and maximum plantar pressure, center of pressure, and ground reaction force were measured during each event phase. The mean and standard deviations for each variables were calculated and differences were validated with the independent sample t-test. A p-value <0.05 was considered statistically significant. The results were as follows. 1)The ideal stance is a stable, balanced position with more than 65% of weight on the right foot. There was significant difference in mean left plantar pressure, while the maximal plantar pressure and mean right plantar pressure did not differ significant. 2)The effective backswing of a skilled player is comprised a rightward shift in weight to build maximum energy. More than 90% of the weight was on the right foot. There was a significant difference in the mean left plantar pressure, while the maximal plantar pressure and mean right plantar pressure did not differ significantly. 3) For an effective impact, a rapid shift in weight to the left foot is essential, so that a power hit is obtained. Significant difference in the mean and maximum plantar pressures of both feet were observed. 4)Follow-through requires wight balance, more on the right than the left, without leaning leftward. There was no significant difference in the mean or maximum plantar pressure. 5)The center of plantar pressure should move from the center of the foot to the toe. 6)The analyses of the ground reaction force suggest that a good swing involves a gradual shift in weight to the right side and a rapid leftward shift at impact. Good balance, with the center of gravity on the right side at follow-through, is also required.