• Proceedings of the Botanical Society of Korea Conference
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• 1999.07a
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• pp.45-49
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• 1999

Plant cell culture is emerging to express bioactive foreign proteins because it has several advantages in that it is safe, economical, genetically stable and eukaryotic expression system comparing with other expression systems. However several limitations such as slow growth rate, low expression level and lack of well established down stream process need to be answered. As a preliminary approach to produce the immunologically interested molecules through the plant cell culture, we tested if granulocyte-macrophage colony stimulating factors (GM-CSFs) from both murine (mGM-CSF) and human (hGM-CSF) are produced as a biologically active form through plant cell culture. The murine and human GM-CSF genes were cloned into the plant expression vector, pBI121, and Ti-plasmid mediated transformation of tobacco leaves was conducted using Agrobacterium tumefaciens harboring both recombinant GM-CSF (rGM-CSF) genes. Cell suspension culture was established from the leaf-derived calli of transgenic tobacco plant. Northern blot analysis indicated the expression of the introduced mGM-CSF gene in both transgenic plant and cell suspension cultures. In addition, the biological activities of both murine and human GM-CSF from plant cell culture were confirmed by measuring the proliferation of the GM-CSF dependent FDC-PI and TF-1 cells, respectively.

• Coupled systems mechanics
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• v.1 no.1
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• pp.39-57
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• 2012

This study intends to explore dynamic interaction behaviors between actively controlled maglev vehicle and guideway girders by considering the nonlinear forms of electromagnetic force and current exactly. For this, governing equations for the maglev vehicle with ten degrees of freedom are derived by considering the nonlinear equation of electromagnetic force, surface irregularity, and the deflection of the guideway girder. Next, equations of motion of the guideway girder, based on the mode superposition method, are obtained by applying the UTM-01 control algorithm for electromagnetic suspension to make the maglev vehicle system stable. Finally, the numerical studies under various conditions are carried out to investigate the dynamic characteristics of the maglev system based on consideration of the linear and nonlinear electromagnetic forces. From numerical simulation, it is observed that the dynamic responses between nonlinear and linear analysis make little difference in the stable region. But unstable responses in nonlinear analysis under poor conditions can sometimes be obtained because the nominal air-gap is too small to control the maglev vehicle stably. However, it is demonstrated that this unstable phenomenon can be removed by making the nominal air-gap related to electromagnetic force larger. Consequently it is judged that the nonlinear analysis method considering the nonlinear equations of electromagnetic force and current can provide more realistic solutions than the linear analysis.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.6
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• pp.633-641
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• 2015

The ROM (roll over mitigation) system is a next-generation suspension system that can improve vehicle-driving stability and ride comfort. Currently, mass-produced safety systems, such as ESC (electronic stability control) and ECS (electronic control suspension), enable measurements of longitudinal and lateral acceleration as well as yaw rate through inertial sensor clusters, but they lack direct measurements of the roll angle. Therefore, in this paper, a roll angle estimation algorithm from ESC system sensors and tire normal force has been proposed. Furthermore, this study presents a method for roll over mitigation force distribution between the front and rear of a ROM system. Performance and reliability of the roll angle estimation and roll over mitigation force distribution were investigated through simulations. The simulation results showed that the proposed control algorithm and strategy are reliable during vehicle rollovers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.160-166
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• 2018

This paper proposes an advanced suspension system and reports its performance in the framework of the preview control algorithm based on the RPS (road profile sensing) system and MSD system with the multi-stage damping characteristics. Typical disturbance inputs that cause excessive vibration and steering instability of an automobile are irregular obstacles that protrude or sink into the road surface to be driven. The control performance can be improved if information on the existence and shape function of its obstacle is known. Based on the results of the previous study, advanced research that uses the actuating system has been processed to be commercialized practically. For this purpose, a switching algorithm between the control logic and the multi-stage damping system was developed and its connectivity is presented. To verify the applicability of an actual vehicle, the proposed control system was implemented in full vehicle models and simulations were performed. The proposed system using the 3-DS actuator system, which is applied for structural simplicity, can improve the ride comfort and steering stability. In addition, the results indicate the feasibility of the intelligently controlled suspension system.

• Korean Journal of Plant Tissue Culture
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• v.22 no.2
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• pp.111-114
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• 1995

To produce ${\gamma}$-linolenic acid (GLA) by cell cultures of Lithospermum erythrorhizon, we optimized medium compositions including carbon sources, nitrogen sources and growth regulators. MS basal medium supplemented with 1.0 mg/L 2, 4-D was effective for callus induction from mesophyll tissue. Addition of sucrose at 88mM concentration induced active proliferation of suspension cells and increased GLA content. Increased supplement of potassium nitrate as nitrogen source resulted in proliferous cell growth and increased total fatty acid content Abscisic acid increased cell growth and fatty acid content in callus culture, whereas as it had an inhibitory effect in suspension cell culture.

• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.59-64
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• 2011

Degree of unsaturation in fatty acid molecules plays an important role in the formation of vesicles. Vesicle formation from C18 fatty acids with different amount of double bonds such as oleic acid, linoleic acid and linolenic acid with the incorporation of 1,2-dipalmitoyl-sn-glycerol-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DPPE-PEG2000) have been examined by TEM. Critical vesicular concentrations (CVC) of the vesicle suspension are determined by turbidity and surface tension methods. The CVC of fatty acids increases when the amount of unsaturation in the alkyl chain increases. On the other hand, stability of vesicle suspension has been examined by using particle size and zeta potential at $30^{\circ}C$. There was a dramatic decrease in particle size measurement from mono-unsaturation to tri-unsaturation which could be due to the effect of fluidity in the membrane bilayer caused by different degree of unsaturation. The values of zeta potential for vesicles that were formed without the incorporation of DPPE-PEG2000 were in the range of -70 mV to -100 mV. It has been observed that the incorporation of DPPEPEG2000 to the vesicle reduces the magnitude of zeta potential. However, this phenomenon does not obviously seen in fatty acid vesicles formed by linoleate-linoleic acid and linolenate-linolenic acid. We therefore conclude that the addition of DPPE-PEG2000 does not effectively improve the stability of the linoleate-linoleic acid and linolenatelinolenic acid vesicle at pH 9.0 after the evaluation of their particle size and zeta potential over a period of 30 days. Although the vesicles formed were not stable for more than 10 days, they have displayed the potential in encapsulating the active ingredients such as vitamin E and calcein. The results show that the loading efficiencies of vitamin E are of encouraging value.

• Korean Chemical Engineering Research
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• v.51 no.2
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• pp.279-284
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• 2013

The phenolic beads in macrosize range were obtained by suspension polymerization at $98^{\circ}C$ from phenol and formaldehyde in the presence of basic catalyst with a phenol to formaldehyde (P/F) range of 1:1~1:4, and they were carbonized to spherical carbon beads under nitrogen at $700^{\circ}C$. Thermal analysis on spherical phenolic beads obtained by suspension polymerization showed that the postcuring process is essential. In order to optimize the suspension polymerization, the effects of the P/F molar ratio, the pH of catalyst, and the molecular weight of stabilizer on the size distribution and yield of spherical phenol beads were examined separatively. The particle size was increased whereas the yield was decreased with P/F molar ratio. The increasing basicity of catalyst made the particle size to increase, while the molecular weight of stabilizer had more effect on the yield rather than on the particle size distribution. The thermal stability of the spherical phenolic beads obtained through postcure was also examined by TGA. The phenol beads of high P/F ratio still showed the weight loss at $220^{\circ}C$ even after postcure due to the high possibility of dibenzyl ether, while those of low P/F ratio showed the steady decrease in weight during $220^{\circ}C$ to $400^{\circ}C$, which showed that the optimal P/F ratio was 1:2.

• The Korean Journal of Physiology
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• v.9 no.1
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• pp.1-11
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• 1975

The present experiments were carried out to investigate the active center of sodium and potassium ion activated adenosine triphosphatase. An ATPase, activated by sodium ion Plus potassium ion in the presence of magnesium ion, and inhibited by ouabain, has been obtained from rabbit red cell ghosts. The ATPase activity was measured by inorganie phosphate released from ATP. From this values of the measured inorganic phosphate, the activity of ATPase was calculated. The following results were observed. 1. The activity of $(Na^++K^+)-ATPase$ is inhibited by ouabain. This effect may not be due to an effect on sulfhydryl groups, amino groups, carboxyl groups, imidazole groups and hydroxyl groups. 2. The $(Na^++K^+)$-activated enzyme system is inhibited by p-chloromercuribenzoate and by d nitroflurobenzene, and this effect may be due to an effect on sulfhydryl groups. These results indicate that the sulfhydryl groups is attached to sodium-potassium dependent adenosine triphosphate, an aspect of the pump. 3. The $(Na^++K^+)-activated$ enzyme system is inhibited by maleic anhydride and this inhibition is reversed by lysine. This Seems to indicate that the active center of this enzyme is the amino groups. 4. The $(Na^++K^+)$-activated enzyme system is inhibited by iodoacetamide and this inhibition is reversed by the simultaneous present of cysteine and aspartic acid in the suspension medium. This result indicates that this enzyme contains sulfhydryl groups and carboxyl groups. 5. The $(Na^++K^+)-ATPase$ activity is accelerated by adrenaline and this effect is abolished by aspartic acid. This effect of aspartic acid indicate that carboxyl group might be involved in the hydrolysis of ATP by the enzyme system. On the hydrolysis of ATP by the enzyme system. On the basis of these experiments it f·as suggested that the active center of $(Na^++K^+)-activated$ ATPase contains sulfhydryl groups, amino groups and carboxyl groups.

• Korean Journal of Plant Tissue Culture
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• v.28 no.2
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• pp.69-74
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• 2001

Calli were induced on MS medium supplemented with 0.5 mg/L 2,4-D by using the leaf explants of haploid which were derived from the diploid and haploid of Nicotiana tabacum cv BY4. These calli were subcultured on MS medium with the combination of 2.0 mg/L 2,4-D, 1.0 mg/L kinetin and 0.1 mg/L BAP. Cell propagation of diploid plants were good in a combination of 2.0 mg/L 2,4-D, 0.1mg/L BAP in vitro conditions, suspension cultures were conducted in equal condition. Homogenized suspension cultured cells were smeared 2.0 mL each on MS medium with 0~100 $\mu$M PFP, to select the resistant colony to PFP, and were examined after 10d, 20d and 30d. Measurment of fresh weight of cells after 30d of culture shows that with more concentration of PFP in medium the fresh weight of the cells decreased. In case of diploid, selected callus was the highest in vitro treated with 5 $\mu$M PFP. It was higher than control until 100 $\mu$M PFP. The active degree of catalase was the highest in vitro with 5 $\mu$M PFP but the lowest in vitro with 10 $\mu$M PFP on the other hand, in case of haploid plant, the active degree of peroxidase and catalase was the highest in vitro treated with 50 $\mu$M PFP. It's sure that enzyme active degree of between diploid and haploid had big differences.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.10
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• pp.48-57
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• 2008

MR Fluid, one of functional fluids, is developed for the application to automobile products. MR CDC damper using MR fluid has following principles. When ar electric current is applied to the solenoid, apparent viscosity of MR fluid passing through the annular gap which acts as magnetic circuits varies directly as the intensity of the current. These devices have a simple structure and excellent lime response characteristics, emerging as the alternatives of the conventional semi-active suspension systems. In this study, a design procedure of the magnetic circuit through the solenoid fore and the flux ring functioning as a magnetic path is investigated so as to optimize the design and performance of MR CDC dampers for the vehicles. In addition, an operating point on the B-H curve, the magnetization according to the variation in the annular gap, the pole piece width and the density of MR fluid are studied to design the optimal piston head within the restrained dimension range.