• The Korean Journal of Physiology
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• v.27 no.2
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• pp.185-197
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• 1993

The rostral ventrolateral medulla (RVLM) includes vasopressor neurons, which transmit activation signals to the intermediolateral nucleus (IML) of the spinal cord, where the preganglionic sympathetic nucleus is located, to raise arterial blood pressure (BP). However, controversy exists as to the possible depressor area in the RVLM and the pathway involved. The present study persued evidence far the location of depressor neurons and the pathway by simultaneously observing changes in BP and the firing rate (FR) of cardiovascular neurons (CVNs) in the RVLM during the somatosympathetic reflex (SSR) elicited by peripheral nerve stimulation, since CVNs are known to contribute to the generation of the sympathetic nerve discharge. In 42 cats, anaesthetized with $\alpha-chloralose$, single unit recording was performed, using carbon filament electrodes inserted into the RVLM, enabling estimation of the post R wave unit histogram (PR-UNlT) and the spike triggered average of sympathetic nerve discharge (STA-SND), allowing identification of CVNs. Antidromic stimulation of spinal $T_2$ segment was followed to determine whether the identified CVN projects axonal endings to the spinal cord (reticulospinal neuron). The sciatic nerve was electrically stimulated at $A\delta-intensity$ (1 mA, 0.1 ms), 1 Hz and C-intensity (10 mA, 0.5 ms), 20 Hz to elicit the depressor, and pressor responses of the SSR, respectively. Simultaneous measurement of CVN firing rate was made. Experimental results are summarized as follows. 1) 20 out of 98 CVNs had axonal projections to the spinal cord and 17 out of 98 CVNs showed FR changes during SSR. 2) Response patterns of FR and BP during SSR were classified into 8 types. 3) These 8 different response patterns could be further classified into those from pressor and depressor neurons. These results demonstrate that some CVNs were identifiable as reticulospinal neurons responding to anti-dromic stimulation and that CVNs operating as depressor neurons as well as pressor neurons exist in the RVLM, both of which are involved with SSR mediation. Therefore, evidence was found that an independent depressor pathway might be involved in the mediation of SSR.

• Investigative Magnetic Resonance Imaging
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• v.16 no.1
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• pp.6-15
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• 2012

Purpose : The objective of this study was to develop background gradient correction method using excitation pulse profile compensation for accurate fat and $T_2{^*}$ quantification in the liver. Materials and Methods: In liver imaging using gradient echo, signal decay induced by linear background gradient is weighted by an excitation pulse profile and therefore hinders accurate quantification of $T_2{^*}$and fat. To correct this, a linear background gradient in the slice-selection direction was estimated from a $B_0$ field map and signal decays were corrected using the excitation pulse profile. Improved estimation of fat fraction and $T_2{^*}$ from the corrected data were demonstrated by phantom and in vivo experiments at 3 Tesla magnetic field. Results: After correction, in the phantom experiments, the estimated $T_2{^*}$ and fat fractions were changed close to that of a well-shimmed condition while, for in vivo experiments, the background gradients were estimated to be up to approximately 120 ${\mu}T/m$ with increased homogeneity in $T_2{^*}$ and fat fractions obtained. Conclusion: The background gradient correction method using excitation pulse profile can reduce the effect of macroscopic field inhomogeneity in signal decay and can be applied for simultaneous fat and iron quantification in 2D gradient echo liver imaging.

• Explosives and Blasting
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• v.30 no.2
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• pp.86-97
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• 2012

Ground vibration induced by a bench blasting in the construction site should cause the damage to the structure and indirect damage to a human body, and the vibration level is most practical descriptor for regulating the damage to human body and peak particle velocity is the descriptor for direct damage assesment of the structure. Meantime, the vibration level has not been considered for the blasting design but this study is the case that apply not only peak particle velocity but also vibration level on the blasting design. Also, we strongly believe that this study will be helpful for the management in the blasting site which some civil appeal is concerned. Total 232 measurements of both ppv and vibration level was used to estimate the scale distance. When the regulating threshold was ppv 0.3 cm/s and vibration level 75 decibel, the charge per delay to be estimated with vibration level could be recommended by 1.2~1.4 times than it of ppv. So, it is proven that considering vibration level on the blasting design is reasonable for not only prevention of the civil appeals but also effective blasting. Again, the blasting design which follows the law, "Noise and Vibration Control Act" can actually serve good condition to carry much more economical and effective blasting. The instruments used for this study are the SV-1 model, as first instrument in korea which can measure vibration velocity and vibration level at the same time.

• Journal of the Korean Chemical Society
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• v.26 no.6
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• pp.369-377
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• 1982

The technique of combined-measurement of reflectance and ellipsometric parameters was used for studying the anodic film formed on nickel surface in basic solutions. An ellipsometer was automated for transient measurements by way of modulating the plane-polarized light with the Faraday effect. Surface film was formed electrochemically by applying a potential step from the reduction potential range to the passivation range on a polished, high-purity, polycrystalline nickel specimen. From that instant, the changes in the reflectance(r) and the ellipsometric parameters(${\Delta},{\Psi}$) of the surface film were recorded by the automatic ellipsometer. Three exact simultaneous equations including these optical signals, ${\Delta},{\Psi}$ and r were solved numerically with a computer in order to determine the optical properties, n, k, and the thickness, ${\tau}$, of the surface film. From the computed results which showed dependence on pH and time, it was found that passivation of nickel can be effectively attained by surface film thinner than $15{\AA}$ and this passivation film has a small optical absorption coefficient. It seemed that a high pH environment enhances the rate of passivation and is favorable for a denser structure of the surface film. The experimental evidence is in accordance with the hypothesis that the composition of the passive film can be approximated by $Ni(OH)_2$ in the early stage of passivation and that as time passes the composition changes partially toward that of NiO through dehydration.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.171.2-171.2
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• 2016

The 2-dimensiona electron gas (2DEG) layers have opened tremendous interests in the heterooxide interfaces formed between two insulating materials, especially between LaAlO3 and $SrTiO_3$. The 2DEG layers exhibit extremely high mobility and carrier concentrations along with metallic transport phenomena unlike the constituent oxide materials, i.e., $LaAlO_3$ and $SrTiO_3$. The current work inserted artificially the interfacial layer, $Sr_xCa_{1-x}TiO_3$ between $LaAlO_3$ and $SrTiO_3$, with the aim to controlling the 2-dimensional transports. The insertion of the additional materials affect significantly their corresponding electrical transports. Such features have been probed using DC and AC-based characterizations. In particular, impedance spectroscopy was employed as an AC-based characterization tool. Frequency-dependent impedance spectroscopy have been widely applied to a number of electroceramic materials, such as varistors, MLCCs, solid electrolytes, etc. Impedance spectroscopy provides powerful information on the materials system: i) the simultaneous measurement of conductivity and dielectric constants, ii) systematic identification of electrical origins among bulk-, grain boundary-, and electrode-based responses, and iii) the numerical estimation on the uniformity of the electrical origins. Impedance spectroscopy was applied to the $LaAlO_3/Sr_xCa_{1-x}TiO_3/SrTiO_3$ system, in order to understand the 2-dimensional transports in terms of the interfacial design concepts. The 2-dimensional conduction behavior system is analyzed with special emphasis on the underlying mechanisms. Such approach is discussed towards rational optimization of the 2-dimensional nanoelectronic devices.

• Journal of Digital Convergence
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• v.16 no.8
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• pp.301-309
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• 2018

The purpose of this study was to investigate the immediate effect of lumbar support and ischial pad on neck, trunk angle and chest expansion for stroke patients using wheelchair. Fifteen stroke patients were measured repeatedly when a lumbar support using(L support), a Ischial pad using(I Pad), a Lumbar support with ischial pad using(L With I), and non using it(Non using). The measurement of the neck and trunk angle was confirmed using a mobile phone camera, and chest expansion was performed using a tapeline. L With I increased significantly in neck and trunk angle and lower chest expansion than non using. This study shows that simultaneous use of lumbar support and ischial pad for stroke patients using wheelchair can increase the neck and trunk angle, chest expansion immediately. Future studies will need to identify more long-term changes by continuing intervention with more subjects.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.188.2-188.2
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• 2015

The presence of the conduction interface in epitaxial $LaAlO_3/SrTiO_3$ thin films has opened up challenging applications which can be expanded to next-generation nano-electronics. The metallic conduction path is associated with two adjacent insulating materials. Such device structure is applicable to frequency-dependent impedance spectroscopy. Impedance spectroscopy allows for simultaneous measurement of resistivity and dielectric constants, systematic identification of the underlying electrical origins, and the estimation of the electrical homogeneity in the corresponding electrical origins. Such unique capability is combined with the intentional control on the interface composition composed of $SrTiO_3$ and $CaTiO_3$, which can be denoted by $SrxCa1-_xTiO_3$. The underlying $Sr_xCa1-_xTiO_3$ interface was deposited using pulsed-laser deposition, followed by the epitaxial $LaAlO_3$ thin films. The platinum electrodes were constructed using metal shadow masks, in order to accommodate 2-point electrode configuration. Impedance spectroscopy was performed as the function of the relative ratio of Sr to Ca. The respective impedance spectra were analyzed in terms of the equivalent circuit models. Furthermore, the impedance spectra were monitored as a function of temperature. The ac-based characterization in the 2-dimensional conduction path supplements the dc-based electrical analysis. The artificial manipulation of the interface composition will be discussed towards the electrical application of 2-dimensional materials to the semiconductor devices in replacement for the current Si-based devices.

• IMMUNE NETWORK
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• v.1 no.3
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• pp.213-220
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• 2001

Background: A previous study has shown that Euonymus alatus (EA) has an antidotic activities against inflammation, suggesting possibility that EA can exert this beneficial effects to liver injury by an initial protection against drug-induced hepatocyte demage. The present study was undertaken to evaluate the protective effect of EA-extract on experimentally induced hepatitis in ICR mice and to investigate some mechanisms responsible for its action. Methods: Water EA extract was used in this experiments. The mice received i.p. a dose of 700 mg/kg galactosamine (GalN) together with $5{\mu}g/kg$ of endotoxin (LPS), or received i.v. 12 mg/kg of concanavalin A (Con A). EA (4 mg/mouse) was administrated on day -2, -1 and 0 before induction of liver injury. Liver injury was assessed by measurement of serum alanin amino-transferase (SGPT) levels on 9 hr after GaIN.LPS, or 8 hr after con A administration. Results: Treatment with either GaIN or LPS alone did not cause hepatitis. However, simultaneous administration of GalN and LPS to mice resulted in LPS-dose dependent fulminant hepatitis. GaLN/LPS-induced liver injury was reduced when mice were given EA for 3 days before induction. This preventive effect of Ea was more prominent when EA was given by intraperitoneal route rather then by oral route. Pretreatment of EA or dexamethasone inhibited significantly $TNF{\alpha}$ production in GalL/LPS-injured mice. However, EA-treatment did not influence $TNF{\alpha}$-induced hepatitis in GalN-sensitized mice, suggesting that $TNF{\alpha}$ is likely to act as one of final mediators of endotoxin action and the protective effect of EA might be manifested chiefly by inhibition of endotoxin-induced $TNF{\alpha}$ production, not by blocking the $TNF{\alpha}$-action. Injection of Con A into mice evoked remarkable liver injury in a dose dependent fashion. This liver damage was reduced by EA-pretreatment. Dexamethasone significantly reduced both GalL/LPS-induced and Con A-induced liver damages, showing synergism with EA. However, indomethacin reduced only GalN/ LPS-induced hepatitis, not for Con A-induced hepatitis. Conclusion: These results led to the conclusion that EA may be able to contribute at least in part to prevent the drug-induced hepatotoxicity, and that its anti-hepatitis effects might be manifested directly by modulation of endogenous mediators, such as leukotriese D4, $TNF{\alpha}$ and free radical, and indirectly by regulation of immune mediated responses. Also these results suggested that EA could be developed as a potential antidotic agent.

• Journal of the Korea Convergence Society
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• v.9 no.8
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• pp.101-108
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• 2018

This study aimed to investigate the blood glucose regulatory effect of barley noodles contained mulberry leaves water extract (MLWE) in diabetic mice in order to provide fundamental data as a functional food. ICR mice were divided into six groups as follows: normal control, positive control, barley control, mulberry control, barley+MLWE 2.5% and barley+MLWE 5% groups. High fat/high carbohydrate diet was fed for 4 weeks and diabetes mellitus was induced by i.p. injection of streptozotocin and nicotinamide. After diabetes induction, experimental diet was supplemented for 2 weeks and simultaneous measurement of body weight, blood glucose (including glucose tolerance test), liver function and blood lipid profile was conducted. As a result, there was less decrease in body weight compared to the positive control group in the groups that supplemented barley and MLWE together than the group ingesting barley and MLWE alone. In addition, regulatory effects on blood glucose, liver function and blood lipid concentration were also stronger in barley and MLWE concurrently supplemented groups. Consequently, combination of barley and MLWE was effective in the regulation of body weight, blood glucose, liver function, and blood lipid in diabetic mice. Therefore, this recipe could be a promising strategy for beneficial effects in the patients of diabetes mellitus.

• Journal of Korean Society of Transportation
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• v.24 no.3 s.89
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• pp.17-27
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• 2006

Car following model is a theory that examines changes of condition and interrelationship of acceleration deceleration. headway, velocity and so on closely based on the hypothesis that the Posterior vehicle always follows the preceding vehicle. Car following mode) which is one of the research fields of microscopic traffic flow was first introduced in 1950s and was in active progress in 1960s. However, due to the limitation of data gathering the research depression was prominent for quite a while and then soon was able to tune back on track with development in global positioning system using satellite and generalization of computer use. Recently, there has been many research studies using reception materials of global Positioning system(GPS). Introducing GPS technology to traffic has made real time tracking of a vehicle position possible. Position information is sequential in terms of time and simultaneous measurement of several vehicles in continuous driving is also practicable. Above research was focused on judging whether it is feasible to overcome the following model research by adopting the GPS reception device that was restrictively proceeded due to the limitation of data gathering. For practical judgment, we measured the accuracy and confidence level of the GPS reception devices material by carrying out a practical experiment. Car following model is also being applied in simulations of traffic flow analysis, but due to the difficulty of estimating parameters the basis of the above result. it is our goal to produce an accurate calibration of car following model's parameters that is suitable in this domestic actuality.