• Herbal Formula Science
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• v.8 no.1
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• pp.329-342
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• 2000

Citri Reticulatae Viride Pericarpium(CRVP) is being used to regulate the flow of Q(氣) However, the mechanism of it's pharmacological actions is not well understood. The purpose of this research was to investigate effects of CRVP contractil response of isolated on abdominal and femoral artery in rabbits and renal artery in pigs. 1. Abdominal artery was relaxed by CRVP in a dose-dependent manner. 2. Femoral artery was relaxed by CRVP in a dose-dependent manner 3. Pretreatment with methylene blue and indomethacin did not inhibited CRVP induced relax in abdominal artery and femoral artery. 4. Renal artery was relaxed by $H_{2}O$ fraction in a dose-dependent manner, 5. Pretreatment with regitine inhibited $H_{2}O$ fraction(CRVP) induced relax in renal artery in a dose-dependent manner. 6. Renal artery was not relaxed by hexane fraction(CRVP) in a dose-dependent manner. 7. Pretreatment with regitine$(10^{-7}M)$ was relaxed by methylene chloride(MC)(CRVP) and $H_{2}O$ fraction in a $0.5{\mu}g/m{\ell}$.

• Steel and Composite Structures
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• v.15 no.5
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• pp.481-505
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• 2013

This paper focuses on thermal post-buckling analysis of functionally graded beams with temperature dependent physical properties by using the total Lagrangian Timoshenko beam element approximation. Material properties of the beam change in the thickness direction according to a power-law function. The beam is clamped at both ends. In the case of beams with immovable ends, temperature rise causes compressible forces and therefore buckling and post-buckling phenomena occurs. It is known that post-buckling problems are geometrically nonlinear problems. Also, the material properties (Young's modulus, coefficient of thermal expansion, yield stress) are temperature dependent: That is the coefficients of the governing equations are not constant in this study. This situation suggests the physical nonlinearity of the problem. Hence, the considered problem is both geometrically and physically nonlinear. The considered highly non-linear problem is solved considering full geometric non-linearity by using incremental displacement-based finite element method in conjunction with Newton-Raphson iteration method. In this study, the differences between temperature dependent and independent physical properties are investigated for functionally graded beams in detail in post-buckling case. With the effects of material gradient property and thermal load, the relationships between deflections, critical buckling temperature and maximum stresses of the beams are illustrated in detail in post-buckling case.

• Journal of Nutrition and Health
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• v.33 no.3
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• pp.257-262
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• 2000

This paper is to report our findings that vitamin B6 and folate nutritional state in the rural elderly population with alcohol dependency is poor. The present study was carried out to assess vitamin B6 and folate status in the 17 rural elderly subjects with alcohol dependency and 15 age-and sex-matched controls. Plasma and red cell folate concentrations were analyzed microbiologically, and pyridoxal-5-phosphate dependent erythrocyte alanine aspartate transminase(EAST) activity coefficients were determined using enzyme-coenzyme saturation kinetics. There was no difference in the amount of vitamin consumed between the two groups, and their intakes were 64% and 74.7%, respectively of the Korean dietary recommended allowances for vitamin B6 and folate. The mean percent activation for EAST of the total subjects was greater than 80%, suggesting an inadequate vitamin B6 status between the two groups. Folate concentrations in the red cell, but not in the plasma were significantly lower in the alcohol dependent(141.9ng/ml) subjects than that of the control(233.2ng/ml). Cigarette smokers had lower vitamin B6 and folate levels. Plasma and red cell folate levels were highest among the non-smoking, non-alcohol dependent subjects(11.7 and 257.3ng/ml, respectively) and lowest in the smoker-alcohol dependent group(6.7 and 132.9ng/ml). Finding ways to improve vitamin nutritional state such as vitamin supplementation might be necessary for the rural elderly people, especially for those with alcohol dependency.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.7
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• pp.989-996
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• 2001

High-speed and low-speed flows are simulated numerically by flowfield-dependent mixed explicit-implicit (FDMEI) method. This algorithm depends on implicitness parameters of convection, diffusion, diffusion gradients, and source terms which are calculated from the changes of local Mach, Reynolds, Peclet, and Damkohler numbers between adjacent nodes. Convection phenomena or shock waves are resolved from Mach number-dependent implicitness parameters whereas diffusion or viscous actions are simulated by Reynolds number or Peclet number-dependent implicitness parameters. Fluctuation components of all variables are properly accommodated spatially and temporally in the FDMEI procedure. To illustrate, some benchmark example problems are presented for comparisons of the FDMEI results with other available data. These results appear to be encouraging and point toward the need for further investigations of the FDMEI theory.

• Structural Engineering and Mechanics
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• v.44 no.1
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• pp.109-125
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• 2012

Post-buckling behavior of Timoshenko beams subjected to uniform temperature rising with temperature dependent physical properties are studied in this paper by using the total Lagrangian Timoshenko beam element approximation. The beam is clamped at both ends. In the case of beams with immovable ends, temperature rise causes compressible forces end therefore buckling and post-buckling phenomena occurs. It is known that post-buckling problems are geometrically nonlinear problems. Also, the material properties (Young's modulus, coefficient of thermal expansion, yield stress) are temperature dependent: That is the coefficients of the governing equations are not constant in this study. This situation suggests the physical nonlinearity of the problem. Hence, the considered problem is both geometrically and physically nonlinear. The considered highly non-linear problem is solved considering full geometric non-linearity by using incremental displacement-based finite element method in conjunction with Newton-Raphson iteration method. The beams considered in numerical examples are made of Austenitic Stainless Steel (316). The convergence studies are made. In this study, the difference between temperature dependent and independent physical properties are investigated in detail in post-buckling case. The relationships between deflections, thermal post-buckling configuration, critical buckling temperature, maximum stresses of the beams and temperature rising are illustrated in detail in post-buckling case.

• Archives of Pharmacal Research
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• v.17 no.4
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• pp.226-230
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• 1994

The characteristics of voltage-dependent ^{45}Calcium$ uptake and norepinephrine release as factors controlling neural activities in the hypothalamus which is an important regulatory site for cardiovascular function wre studied. Two groups of animals : male spontaneously hyperterisive rat (SHR) and age-matched nomotensive wistar rat (NW) were used in this study. Animals at 4, 6 and 16 weeks of age were sacrificed by decapitiation and the hypothalamus was dissected out. Voltage-dependent calcium uptake and norepinephrine release were determined from hypothalamic synaptosomes either in low potassium (5 mM) or high potassium (41 mM) stimulatory conditions by using ^{45}Ca$ isotope and HPLC-ECD techniques. Degrees of voltage-dependent ^{45}Calcium$ uptake and norepinephrine release evoked by calcium uptake in the hypothalamus of prehypertensive phase (4 weeks old) of SHR were significantly smaller than those in NW of the same age. However, in the developmental phase (6 weeks old) and the established phase (16 weeks old) of hyperrtension in SHR, degrees of voltage-dependent ^{45}Calcium$ uptake and norepinephrine release were similar to those of age-matched normotensive wistae eats. These data imply that the deficit in hypothalamic norepinephrine release might be an important underlying factor for the development of hypertension in SHR.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.316-322
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• 2002

This paper presents the temperature-dependent hysteresis identification of an electro-rheological (ER) fluid under various operating temperatures using the Preisach model. As a first step, polymethylaniline (PMA) particles are prepared and mixed with silicone oil to make an ER fluid. A couette type electroviscometer is then employed to obtain the field-dependent shear stress. In order to show the suitability of the Preisach model to predict a physical hysteresis phenomenon of the ER fluid, two significant properties; the minor loop property and the wiping-out property are experimentally examined under three dominant temperature conditions. Subsequently, the Preisach model fur the PMA-based ER fluid is identified using experimental first order descending (FOD) curves. The effectiveness of the identified hysteresis model is verified in the time domain by comparing the predicted field-dependent shear stress with the measured one under the both specified and unspecified temperatures. In addition, the hysteresis model proposed in this work is compared to Bingham model.

• Journal of Photoscience
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• v.4 no.2
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• pp.35-40
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• 1997

The sensory transduction processes of blue light in guard cells have been suggested the involvement of Ca$^{2+}$/calmodulin-dependent myosin light chain kinase (MLCK) or MLCK-like proteins. The source of Ca$^{2+}$ required for the signal transduction process was investigated in guard cell protoplasts (GCPs). The GCPs showed the typical H$^+$ pumping activity by blue light (200 $\mu$mol m$^{-2}$ s$^{-1}$) and fusicoccin (10 $\mu$M) under background red light (600 $\mu$mol m$^{-2}$ s$^{-1}$). The blue light-dependent H$^+$ pumping was not significantly affected by the externally changed Ca$^{2+}$ concentrations. The addition of 1 mM Ca$^{2+}$ in the bathing medium ratherly inhibited the H$^+$ pumping. In contrast, the blue light-dependent H$^+$ pumping was inhibited by caffeine and 2,5-di-(tert-butyl)-1,4-benzohydroquinone (BHQ), inhibitor of C$^{2+}$-ATPase in endoplasmic reticulum (ER) without inhibiting the H $^+$ pump. The inhibition by caffeine and BHQ was fully reversible. The extent of inhibition by caffeine and BHQ was larger when they were added together than when added separately. The results suggest that Ca$^{2+}$ required for the blue light-dependent H$^+$ pumping may be released from the intracellular Ca$^{2+}$ stores, probably ER in guard cells.

• Restorative Dentistry and Endodontics
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• v.23 no.2
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• pp.676-681
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• 1998

The purpose of this study is to explain theoretically the mechanism of the frequency-dependent apex locator which can detect the apex of the root in moist canals with blood or other conductible canal irrigants. The frequency-dependent apex locator is based on measuring the ratio of the two impedances of the two alternating currents with different frequencies. We analyzed the changes of the ratio between the two impedances by using differential calculus. Our analysis shows that : 1. When the file is in the moist canal, the ratio between the two impedances is almost constant. 2. As the file approaches the apex of the root, the ratio decreases sharply. By this mechanism, the frequency-dependent apex locator can detect the apex of the-root quite accurately in moist canals.

• YAKHAK HOEJI
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• v.45 no.4
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• pp.419-425
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• 2001

The neuronal cell death induced by excess glutamate (Glu) has been implicated in many acute and chronic neurodegenerative diseases including cerebral ischemia. Glu-induced elevation of intra-cellular $Ca^{2+}$ plays a critical role in the excitotoxicity, partly through the activation of a variety of $Ca^{2+}$ dependent enzymes. In the present study, we investigated the Glu-induced modulation of $Ca^{2+}$/calmodulin-dependent protein kinase IV (CaMK IV), a multifunctional enzyme abundantly present in the nuclei of neurons. The exposure of cultured rat cortical neurons to $100{\mu}$M Glu for 3 min dramatically increased CaMK IV activity up to 4.5-fold of the control-treated enzyme activity. The activation was very rapid, reaching peak at 3 min and then declined gradually. Under the same experimental conditions, time-dependent acute and delayed neuronal cell death was observed. Immunoblot analyses using specific antibodies showed that the expressions of CaMK IV and $CaMKK_{\alpha}$ were time-dependently modulated by Glu. Taken together, these results imply that the modulation of CaMK IV activity by Glu may be involved in the cascade of events resulting in neuronal cell death in cortical cultures.