• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.6
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• pp.1622-1628
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• 2005

This study was undertaken to define the effect of SoPung-Tang extract on hypertension in spontaneous hypertensive rat and norepinephrine- induced arterial contraction in rabbit. In order to investigate the effect of SoPung-Tang extract on contracted rabbit carotid arterial strips, transverse strips with intact or damaged endothelium were used for the experiment using organ bath. To analyze the mechanism of SoPung-Tang extract-induced relaxation, SoPung-Tang extract infused into contracted arterial strips induced by norepinephrine after treatment of indomethacin, Nu-nitro-L-arginine, methylene blue or tetraethylammonium chloride. Blood pressure was significantly decreased five days after administration of SoPung-Tang extract. SoPung-Tang extract relax arterial strip with endothelium contracted by norepinephrine, but in the strips without endothelium, SoPung-Tang extract- induced relaxation was significantly inhibited. SoPung-Tang relax arterial strip contracted by norepinephrine, but in the strips contracted by high $K^+$, SoPung-Tang extract-induced relaxation was significantly inhibited. The endothelium-dependent relaxation induced by SoPung-Tang extract was decreased by the pre-treatment of $N{\omega}$-nitro-L-arginine or methylene blue, but it was not observed in the strips pre-treated with indomethacin or tetraethylammonium chloride. When $Ca^{2+}$ was applied, the strips which were contracted by norepinephrine in a $Ca^{2+}$-free solution, arterial contraction was increased. But pre-treatment of SoPung-Tang extract inhibited contractile response to $Ca^{2+}$. We suggest that SoPung-Tang could be applied effectively for hypertension and may suppress influx of extra-cellular $Ca^{2+}$ through the formation of nitric oxide in the vascular endothelial cells.

• Archives of Pharmacal Research
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• v.19 no.5
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• pp.390-395
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• 1996

To investigate whether $AT_{1}$ receptor antagonists are acting by increasing endothelium-de-pendent and -independent relaxation of aortas in normotensive rats, $AT_{1}$ receptor antagonists, losartan and KR-30988, and angiotensin converting enzyme inhibitor, captopril, were orally administered for two weeks (50 mg/kg, b.i.d.). THe blood pressure, heart rate and body weight were not significantly changed by losartan, KR-30988 and captopril compared to the control group. In aortic preparations, the $pD_{2}$ of KR-30988 for ACh-induced relaxation was 8.33 $\pm$ 0.16, significantly (p <0.05) lower than that of control group $(7.71 \pm 0.15)$. ACh-induced relaxation was significantly increased on losartan-treated group (p<0.01) at $10^{-6}$ M of ACh, and in captopril-treated group (p<0.05) at the range of $10^{-7}$ -$10^{-5}$ M of ACh. The $pD_{2}$ values for histamine-induced relaxatio of losartan, KR-30988 and captopril were 5.57 $\pm$ 0.10, 5.85 $\pm$ 0.21 and 5.60 $\pm$ 0.01, respectively, with significant differences in all groups (p<0.01) compared to that of control group (5.13 $\pm$ 0.09). ACh-induced relaxations of aortic preparations were not changed by pretreatment of indomethacin ($10_{-5}$ M), and completely bolcked by pretreatment of L-NAME $(10_{-5}M)$ in all groups. Sodium nitroprusside-induced relaxations were not significantly changed by all drugs tested in this experiments. These results suggest that $AT_{1}$ receptor antagonists, losartan and KR-30988, enhance the endothelium-dependent relaxatio on aortic preparations through the release of, or increase sensitivity, to nitric oxide in nor-motensive rats.

• Journal of Korean Academy of Nursing
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• v.25 no.2
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• pp.316-329
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• 1995

The purpose of this study was to exame the effectiveness of the hand massage as an independent nursing intervention for the cancer patients undergoing radiation therapy. The data were collected with quasiexperimental research design from 40 subjects-20 for experimental group and 20 for control group-of the radiation oncology department of one university hospital in Seoul from January 10th to March 29th, 1994. Subjects agreed to participate in this study and ranged in age from 18 to 82 years with mean age of 52.63. They had insight of their disease and had undergone radiotherapy at least twice. The hand massage developed by Mariah Snyder (1993) based on the Swedish Massage was administered to the experimental group prior to having radiation therapy at the waiting place of radiotherapy room. Hand massage was given to each hand of patient for five minutes once a day. Measurement of the patient's blood pressure, pulse rate, state anxiety and mood were done before and after the administration of hand massage for 5 days. The data were analyzed with paired t-test, t-test an4 the results were summarized as follows ; 1. After administration of the hand massage, the diastolic blood pressure of experimental group was decreased significantly, while the systolic blood pressure and the pulse rate were decreased, but not significantaly. 2. In the experimental group, the level of anxiety was significantaly lower than control group. The mean scores of the difference of the anxiety level after having hand massage was 8.60 in the experimental group and 0.75 in the control group. 3. The difference of the mood scores before and after the massage in the experimental group was decreased significantly. The mean mood score was decreased 4.80 in the experimental group as compared with 2.02 in the control group. 4. The patients after having the hand massage expressed subjectively their feeling of relaxation, well - being and being enjoyable, the significant decreased of physical symptoms and anxiety. The findings summarized that the use of the hand massage for the cancer patient undergoing radiation therapy Produced significant changes in the level of anxiety and relaxation. Therefore it is recommended to use the hand massage as an intervention for the patients.

• Korean Journal of Pharmacognosy
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• v.40 no.4
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• pp.400-407
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• 2009

The purpose of this study is to investigate hypotensive effect of BDR-29, new herbal preparation of Cassiae Semen, Prunellae Spica, Uncariae Ramulus et Uncus, and Tribuli Semen, in stroke-prone spontaneously hypertensive rats (SHR-SP). SHR-SP were treated with BDR-29 at a dose of 100, 200 mg/kg/day orally for 13 weeks. In the BDR-29 treat group, mean blood pressure and systolic blood pressure were significantly reduced (p<0.05). In phenylephrine-precontracted arota and carotid artery, BDR-29 induced endothelium-dependent vascular relaxation. Hematological findings and biochemical examination revealed no evidence of specific toxicity related to BDR-29. In addition, BDR-29 was markedly attenuated intima-media thickness of thoracic aorta with progression of atherosclerosis. SHR-SP were treated with BDR-29 were significantly increased eNOS expression in arota. These results indicated that BDR-29 improves blood pressure as well as initial atherosclerotic lesion.

• Elastomers and Composites
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• v.55 no.4
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• pp.270-276
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• 2020

The long-term durability of an FKM O-ring used as parts of a hydrogen station was investigated by exposing it to high-pressure gaseous hydrogen for 1, 3, and 7 days at room temperature. Changes in its sealing force were subsequently measured at 150℃ using intermittent compression stress relaxation (CSR). No changes in the tensile properties of FKM O-ring were observed, but its initial and overall sealing forces at 150℃ significantly decreased with increasing exposure time to hydrogen gas. Microvoid formation in the FKM O-ring upon exposure to high-pressure hydrogen was minimized over time after the ring was exposed to atmospheric pressure at room temperature, which prevented changes in its tensile properties. However, applying heat accelerated FKM O-ring oxidation, which decreased its sealing force. These results indicated that identifying changes in the sealing force of rubber materials using intermittent CSR is not sufficient for monitoring changes in mechanical properties under high-pressure hydrogen atmospheres; however, it is suitable for evaluating the long-term durability of sealing materials for hydrogen station applications under similar conditions.

• Journal of the korean Society of Automotive Engineers
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• v.10 no.2
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• pp.61-69
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• 1988

The finite-difference three-dimensional boundary layer procedure of Chang and Patel is modified and applied to solve the boundary layer development on the automobile surface. The inviscid pressure distribution needed to solve the boundary layer equations is obtained by using a low order panel method. The plane of symmetry boundary layer exhibits the strong streamline divergence up to the midbody and convergence thereafter. The streamline divergence in front of the windshield helps the boundary layer to overcome the sever adverse pressure gradient and avoid the separation. The relaxation of the pressure right after the top of the wind-shield, on the other hand, makes the overly thinned boundary layer to readjust and prompts the streamlines to converge into the symmetry plane before the external streamlines do. The three-dimensional characteristics are less apparent after the midbody and the boundary layer is similar to that of the two-dimensional flow. The results of the off-plane-of-symmetry boundary layer are also presented.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.656-661
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• 2000

In the recent trend of electric power supply market, a variable pressure operation supercritical once-through steam generator is highlighted as a thermal power plant for cycling load because of its superiority in load regulation. Almost all thermal power plants of the future are expected to be variable pressure operation supercritical once-through units. APESS(Advanced Plant Engineering & Simulation System) is a dynamic simulation software for power plant which is under being developed by Korea Heavy Industries & Construction Co., Ltd. This paper present the introduction of APESS and the result of simulation for variable pressure operation supercritical once-through steam generator.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.11 no.1
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• pp.31-39
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• 2007

A pedagogic model for blood flow is introduced to help medicine majors understand a simplified version of Navier-Stokes equations which is known to be a good tool for interpreting the phenomena in blood flow. The pressure gradient consists of a time-independent part known as Hagen-Poiseuille's gradient and a time-dependent part known as Sexl's, and the model formula for the volume rate of blood flow is reduced to a very simple form. For demonstration, the blood rate in human aorta system is analyzed in connection with the time-dependence of pressure gradient. It is shown for Sexl's part that the flow rate lags the pressure gradient by ${\pi}/2$, which is thought to be due to the relaxation process involved.

• Journal of Environmental Science International
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• v.25 no.9
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• pp.1213-1222
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• 2016

Given the growing attention to nature and health in modern society, this study considered the role of a waterscape facility as a key element in a landscape's influence on users' physiological and psychological responses. The subjects were 28 university students, and the collected data included systolic and diastolic blood pressure, salivary amylase concentration, semantic differential (SD) scales, and profile of mood states (POMS). As compared to a space without any waterscape element (Type G), relaxation in a space with a waterscape element (Type W) was found to significantly reduce of systolic and diastolic blood pressure and salivary amylase concentration. The SD scale and POMS findings showed that Type W evoked active, bright, dynamic, free, vital, interesting, and cheerful images and improved mood states by enhancing vigor while inhibiting depressive feelings. These findings indicate waterscape facilities can improves users' mood states and may enhance their health.

• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.2
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• pp.1-9
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• 1999

Applicability of the pressure gradient method which is formulated based on pressure gradient is verified against turbulent flow analysis. In the pressure gradient method, pressure gradient instead of pressure itself is obtained using continuity constraint. Since correct pressure gradient is found only when mass conservation is satisfied, pressure gradient method can reflect physics of flow field properly The pressure gradient method is formulated with semi-staggered grid system which locates each primitive variables on the same grid point but evaluates pressure gradient in-between. This grid system ensures easy programming and reflection of correct physics in analysis. For verifying applicability of this method, the pressure gradient method is applied to turbulent flow analysis with low Reynolds number $\kappa$-$\varepsilon$ model. Turbulent flows include fully developed channel flow, backward-facing step flow, and conical diffuser flow. Prediction results show that the pressure gradient method can be applied to turbulent flow analysis. However, the pressure gradient method requires somewhat long computation time. Proper way to find optimum under-relaxation factor, $\gamma$, is also need to be developed.