• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.928-942
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• 2020

The pressure responsiveness property of a skirt-cushion system, which is closely related to the overall performance of Air Cushion Vehicles (ACVs), has always been the difficulty and challenging problem involving cushion aerodynamics and flexible skirt dynamics. Based on a widely used bag and finger skirt-cushion system, the pressure responsiveness properties are investigated numerically. The physical process and mechanism are analyzed and a numerical method for evaluating the pressure responsiveness property is proposed. A cushion-skirt information communication platform is also presented for interchanging the force and the skirt configuration between cushion aerodynamics and flexible skirt dynamics. The pressure responsiveness of a typical skirt-cushion system is calculated and the results demonstrate that the pressure responsiveness property helps alleviate the influence of the cushion height changing on the overall performance of ACVs. Finally, the influences of skirt geometrical and cushion aerodynamic parameters on the pressure responsiveness properties are discussed systematically, giving insight into the design of skirt-cushion systems.

• The Korean Journal of Physiology
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• v.23 no.1
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• pp.151-167
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• 1989

The present study was undertaken to investigate modification in electrophysiological characteristics of cat dorsal horn cells resulting from carrageenin-induced inflammation. The followings were studied; 1) the time-course of changes in responses of the WDR (wide dynamic range) cell 1-3h after subcutaneous injection of carrageenin in its receptive field; 2) the responses of the same dorsal hern cells before and after induction of inflammation; 3) the effect of inflammation on the responsiveness of dorsal horn neurons to algogens (bradykinin & potassium); and 4) the effect of inflammation on the activity of WDR cell following administration of indomethacin and clonidine. Though responses of WDR neuron were increased dramatically during first 1h, the maximal enhancement was observed 3h after induction of inflammation especially by repetitive light tactile stimulus. Following carrageenin injection the majority of WDR neurons (10/15 units) showed enhanced responses to all the mechanical stimuli while in 3 cases responsiveness were intensified during activation by one tactile stimulus (brush or pressure). One cell was unaffected by inflammation and in another case the response was enhanced only to noxious stimulus. Five of 9 cells that could initially be driven by noxious stimulus were activated more strongly by same stimulus and even by tactile stimulus (pressure) following inflammation. In 2 cases neurons were sensitized only to noxious stimulus whereas in another 2 cells that did not show enhanced responses to noxious stimulus responses to light tactile stimulus (pressure) appeared after inflammation. Of 16 LT cells tested 6 responded to squeeze while 4 showed the characteristics of WDR cell following inflammation. No modification in responsiveness was recognized in 3 cells whereas response to only brush was enhanced in another 3 neurons. Following carrageenin injection responses of LT cell to bradykinin or $K^{+}$ were not altered whereas those of WOR neurons to bradykinin or $K^{+}$ were suppressed in 22.2% and 33.3% of cases, respectively. In two of 8 activity of HT cells were inhibited by bradykinin while in five of 8 responsiveness to $K^{+}$ were rather enhanced by inflammation. In the rest inflammation was ineffective. In inflammation-induced animal the receptive field of LT cell was not changed whereas those of WDR cell and HT cell were tremendously expanded. The enhanced responses of WDR neurons to mechanical stimuli resulted from inflammation were suppressed by intravenously injected indomethacin and clonidine suggesting that postaglandin is involved in inflammation-induced sensitization of these cells. The involvement of peripheral and central mechanisms in the modification in responsiveness of dorsal horn cells in the carrageenin-induced inflammation was discussed.

• The Korean Journal of Physiology and Pharmacology
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• v.5 no.6
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• pp.457-466
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• 2001

Glutamate is the most common excitatory amino acid in the brain. Responsiveness of dendrites to the glutamate greatly varies depending on the application sites. Especially, a point of the maximal response to the glutamate of the dendrite is called as 'hot spot'. In our experiment, the responsiveness of the hot spot to the glutamate was investigated in the CA1 pyramidal neuron of the rat hippocampal slice. CNQX, the antagonist of AMPA receptor, blocked 95% of membrane current to the glutamate focal application $(I_{gl}).$ Train ejection of glutamate on one point of the dendrite increased or decreased the amplitude of $I_{gl}$ with the pattern of train, and the changes were maintained at least for 30 min. In some cases, glutamate train ejection also induced calcium dependent action potentials. To evoke long-term change of synaptic plasticity, we adopted ${\theta}-burst$ in the glutamate train ejection. The ${\theta}-burst$ decreased the amplitude of glutamate response by 60%. However, after ${\theta}-burst$ glutamate train ejection, the calcium dependent action potential appeared. These results indicated that the focal application of glutamate on the neuronal dendrite induced response similar to the synaptic transmission and the trains of glutamate ejection modulated the change of AMPA receptor.

• The Korean Journal of Physiology
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• v.21 no.2
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• pp.291-296
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• 1987

There have been reports on the aberration of the control mechanisms of the blood pressure, hormone secretion, and renal functions in spontaneously hypertensive rats (SHR). However, the contribution of the renin-angiotensin system in the maintenance of high blood pressure in SHR is still controversial. Recently, it has been reported that the negative feedback short loop control mechanism of the renin-angiotensin system may be changed in SHR. In the present experiment, it was attempted to explore the possible alterations in the effect of arginine vasopressin (AVP) on the renal function in SHR. Experiments have been done in anesthetized SHR as well as in normotensive Wistar and Sprague-Dawley rats as control groups. Pharmacologic doses of AVP (10-13 mU/rat/10 min) decreased urine volume, excreted amount of creatinine and para-amino-hippuric acid. No differences in these parameters was observed between normotensive and hypertensive rats. AVP increased sodium and potassium excretion, but the responses in SHR were suppressed as compared with normotensive rats. Intravenous infusion of AVP also increased blood pressure in normotensive and hypertensive rats and a vasopressor effect of AVP was attenuated in SHR. There was a positive correlation between the changes in blood pressure and excreted amount of sodium during AVP infusion. These data suggest that the attenuated natriuretic effect of intravenous infusion of AVP may be due to a difference in renal tubular responsiveness to AVP but not due to a difference in vasopressor responsiveness.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.3
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• pp.243-254
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• 2019

In this study, problems of the waterproofing methods in which water leakage occurs in the upper slab of the underground parking lot of apartment houses and the requirements considering the characteristics of the upper slab, and selected the appropriate performance(proposal) for the composite polyurea process are reviewed. As a result of the study, it is necessary to review performance such as responsiveness to upper slab of the multi-unit underground parking lot that is comprised of (1) crack and behavior responsiveness, (2) surface integrity, (3) vertical watertight stability, (4) pressure layer construction, (5) impact and pressure response and (6) vehicle moving load. As a result of evaluating 5 items corresponding to the requirements for the soft and hard complex polyurea, all of them were found to meet the conditions, and each materials were improved by compounding the materials that had problems when applying a single-ply method, thereby clarifying the advantages and disadvantages of the material property. However, in order to apply to the actual site, additional evaluation on site applicability such as mock-up evaluation should be conducted, and subsequent studies on the applicability of the market through review of economic feasibility and maintenance is required.

• Journal of the East Asian Society of Dietary Life
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• v.9 no.3
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• pp.378-385
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• 1999

A reduced NaCl intake for the general population of the world has been recommended to reduce the overall blood pressure level and hence to reduce the overall incidence of cardiovascular disease. A high NaCl diet convincingly contributes to elevated arterial pressure in humans and animal models of hypertension. Among individuals there is considerable variability of blood pressure responsiveness to NaCl intake. In normotensive as well as hypertensive subjects, blood pressure can be judged to be salt sensitivity (SS) when observed to vary directly and substantially with the net intake of NaCl. The prevalence of SS in normotensive adults in the U.S. ranges from 15% to 42% and in hypertensive adults from 28% to 74%. SS is a risk factor for hypertension and may be an important marker in the identification of children for hypertension prevention programs. High NaCl intakes produce expansion of the extracellular fluid volume and thus increase blood pressure. Nonchloride salts of sodium does not expand the extracellular fluid volume and does not alter blood pressure. Blood pressure response to NaCl may be modified by other components of the diet. Low dietary intakes of potassium or calcium augment NaCl-induced increases of blood pressure. Conversely, high dietary intakes of potassium or calcium attenuate NaCl-induced hypertension. A greater intakes of potassium or calcium may prevent or delay the occurrence of hypertension. SS occurs when dietary potassium is even marginally deficient but is dose-dependently suppressed when dietary potassium is increased within its normal range. Orally administered KHCO$_3$, abundant in fruits and vegetates, but not KCl has a calcium-retaining effect which may contributed to its reversal of pressor effect of dietary NaCl. Since nutrients other than NaCl also affect blood pressure levels, a reduced NaCl intake should be only one component of a nutritional strategy to lower blood pressure.

• Tuberculosis and Respiratory Diseases
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• v.42 no.5
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• pp.752-759
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• 1995

Background: Bronchial asthma is characterized by noctunal dyspnea, cough and wheezing because of airway hyperresponsiveness to nonspecific stimuli. These symptoms and signs are also observed in patients with congestive heart failure. Therefore, this is so called "cardiac asthma". There are lots of experimental and clinical datas to suggest that airway dysfunctions occur in acute and chronic congestive heart failure. However, it is still controversial whether bronchial hyperresponsiveness is present in patients with congestive heart failure. To assess whether bronchial hyperresponsiveness is present in patients with congestive heart failure and to demonstrate the relationship between bronchial responsiveness and vascular pressure, we performed methacholine provocation test in 11 patients with mitral valvular heart disease. Methods: All patients were in the New York Heart Association functional class II and treated continuously with digoxin and/or dichlozid and/or angiotensin converting enzyme inhibitor except one patient. All patients were undergone right and left side heart catheterization for hemodynamic measurements. A 20 percent fall of peak expiratory flow rate were considered as positive response to methacholine provocation test. Results: 1) Only one patient who has normal pulmonary artery pressure, pulmonary capillary wedge pressure, cardiac index was positive in methacholine provocation test. 2) Their mean pulmonary artery pressure, pulmonary capillary wedge pressure were $21.72{\pm}9.70mmHg$, $15.45{\pm}8.69mmHg$ respectively which were significantly higher. Conclusion: It is speculated that in stable congestive heart failure patients, bronchial responsiveness as assessed by methacholine provocation test may not be increased.

• Archives of Pharmacal Research
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• v.18 no.3
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• pp.169-172
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• 1995

The changes in blood pressure may relate to the alterations of the responsiveness to vasoconstrictors and vasodilators, and these alterations can arise the modifications in the properties of angiotensin II (AII) receptor. In order to examine the changes of AII receptor in the hypertensive mechanism of renin-dependent hypertensive rats (RHRs; two-kidney, one-ligated type), we compared the equilibrium binding characteristics of $[^3H]$All in adrenal cortex and medulla from RHRs and normotensive rats. The dissociation constants of AII binding in both tissues of RHRs were very similar to those in the respective tissue of normotensive rats. However, the maximum binding was increased from 805 to 1050 fmole/mg protein in the adrenal cortex of RHRs, and decreased from 172 to 126 fmole/mg protein in the adrenal medulla of RHRs. These results imply that the up- and down-regulation of the All receptor population on the cell surface of adrenal glands from RHRs are consorted with the elevation of blood pressure and the activation of renin-angiotensin system.

• The Korean Journal of Pharmacology
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• v.3 no.1
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• pp.5-13
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• 1967

It has been reported by some investigators that pressor response of rabbits to sympathetic ganglionic stimulants was weak. In this paper it was attempted to investigate this problem more thorouglhy in urethane anesthetized rabbits. 1) In rabbits the approximate doses to elicit increase of about 20 mmHg of blood pressure were $100\;{\mu}g/kg$ with DMPP, $50\;{\mu}g/kg$ with Wy-615, $500\;{\mu}g/kg$ with TMA and with nicotine. The pressor activity of these substances was markedly augmented by treating animals with syrosingopine. 2) In adrenal-ligated rabbits pressor activity of the substances was markedly reduced. Treating the adrenal-ligated animals with syrosingopine augmented significantly the pressor activity of these substances except DMPP. Direct injection of DMPP and TMA into the adrenal produced mole pressor response than intravenous injection did. These date suggest that DMPP has greater effect on the adrenal medulla than the other substances. 3) In vagotomized and atropinized rabbits the pressor activity of these compounds was more marked than in normal rabbits. 4) The above facts indicate that the pressor activity of the ganglionic stimulants in rabbits was definitely low than in cats and dogs. The low responsiveness of the rabbits to these agents was discussed in the light of catecholamine releasing mechanisms, and extraganglionic actions of these substances.

• The Korean Journal of Pharmacology
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• v.21 no.1
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• pp.27-33
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• 1985

Either the contraction of isolated was deferens or the increase of heart rate in the pithed rats induced by electrical stimulation was significantly augmented by cadmium administration (10 ${\mu}mols$ of cadmium acetate every other day for 2 weeks i.p.). These stimulation-induced responses were diminished by ${\alpha}_2$-adrenoceptor agonist, clonidine, and the inhibition was antagonized by yohimbine. Furthermore, the increase in diastolic blood pressure by clonidine was also significantly reduced after cadmium administration, whereas that by methoxamine was not influenced with this dose range of cadmium. With these results it may be postulated that the long-term cadmium exposure may preferentially affect the responsiveness of the presynaptic as well as the postsynaptic ${\alpha}_2$-adrenoceptors.