• Journal of the Economic Geographical Society of Korea
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• v.3 no.2
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• pp.43-61
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• 2000

This study investigate the spatial characteristics and corporate networks of foreign business service firms in Korea. Specifically intrafirm and extrafirm organization of foreign firms are addressed utilizing the corporate network perspective. For this purpose, this study conducted questionnaire and interview surveys for the foreign firms. Parent-subsidiary relationships are focused on the mechanisms by which Transnational Corporations (TNCs) headquarters control and coordinate their foreign affiliates and subsidiaries in order to achieve investment purpose in Korea (overseas market expansion). But extrafirm networks of foreign business services firms in Korea do not appear to play an important role in regional development to date. A low proportion of foreign firms is engaged in academics-industry linkages, and a low number o( foreign firms is formally linked with government organizations, research institutes, and trade associations. To conclude, Foreign direct investment firms in business services in Korea are characteristics by globalized intrafirm networks and localized interfirm and extrafirm networks. It is understood that regional development can be vitalized when Korean local firms have close relationships with technologically advanced foreign firms in tacit knowledge capacity. Foreign firms are able to play an important role in the development of business services in Korea. This study suggests that regional foreign direct investment policy should be targeted towards the corporate networking with foreign firms and domestic firms and incrementation of the potential of foreign firms as a knowledge-intensive industry.

• Korean journal of applied entomology
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• v.23 no.3 s.60
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• pp.142-146
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• 1984

Soils suppressive and conducive to ginseng root rot were studied by examining the mycelial growth of Fusarium solani, Phytophthora cactorum, and Sclerotinia sp. on extracts of each type soil. Rhizosphere environments of the two soils were also compared. Mycelial growth of all root rot fungi used was more severely restrained on the suppressive soil extract agar than that of conducive one. However, when heated at 100C for 30 minutes, mycelial growth of F. solani and Sclerotinia sp. was not affected, regardless of type soil used, whereas R. solani and P. cactorum grew better on conducive soil extract. Mycelial growth of all fungi used was stimulated as the treated temperature became higher. No significant differences between the two types of the soil were found in propagules of F. solani. The numbers of total fungi and total bacteria and the ratioes of total fungi to Fusarium and total bacteria to Fusarium were higher in the suppressive soils than in the conducive ones. Higher amount of clay existed in the suppressive soils, Mg and Na contents were lower in those soils than the conducive ones.

• Tuberculosis and Respiratory Diseases
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• v.38 no.1
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• pp.8-15
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• 1991

It has been well known that the integrity of airway epithelium is important in development of bronchial hyperreactivity and bronchial asthma. But the mechanisms involved are still unclear. To evaluate that airway epithelium is able to modulate the contraction of guinea pig tracheal smooth muscle, we investigated the responsiveness of intact and epithelium-denuded tracheal strips to histamine and acetylcholine. And to evaluate whether cyclooxgenase products play a role in this modulatory mechanism, we also investigated the effect of indomethacin pretreatment on the tracheal responsiveness to histamine. Results were as follows: 1) In guinea pig tracheal smooth muscle the presence of airway epithelium significantly reduced the response to histamine. 2) In the presence of indomethacin dose-response curves and $EC_{50}$ values were similar between intact and epithelium-denuded tracheal strips, that is, indomethacin abolished the influence of epithelium on the contracion of tracheal smooth muscle. 3) The response of tracheal smooth muscle to acetylcholine was similar both in the presence and absence of epithelium. These results suggest that airway epithelium of guinea pig may generate an inhibitory signal to decrease the response of tracheal smooth muscle to histamine and cyclooxygenase products may contrbute to the modulation of airway epithelium on the contracion of tracheal smooth muscle.

• Korean Journal of Food Science and Technology
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• v.37 no.4
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• pp.525-531
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• 2005

Quality characteristics of ogapiju prepared by adding different raw materials such as Acanthopanax(0, 0.1, 0.25, 0.5%), Ganoderma lucidum(0, 0.05%), pine needle (0, 0.05%), and red ginseng(0, 0.05%) were evaluated by chemical analyses and sensory evaluation. Total organic acid contents of samples containing ogapi and other medicinal herbs were higher than that of control group. Major free amino acid was histidine. Contents of total amino acid and free sugar were highest in sample C (Acanthopanax 0.1, G. lucidum 0.05, pine needle 0.50, red ginseng 0.05%). In each sample 31-49 volatile components were identified by solid-phase microextraction method, and 42 components were detected by sniff-test using GC-olfactometry. Ogapiju showed higher content of ${\alpha}-copaene$ than control group ${\alpha}-Pinene$, camphene, ${\beta}-pinene$, sabinene, ${\alpha}-terpinene,\;{\gamma}-terpinene$, p-cymene, terpinolene, ${\alpha}-thujone,\;{\beta}-thujone,\;{\alpha}-terpineol$, carvone, and ${\beta}-ionone$ were not identified in control group. Volatile composition of ogapiju was characterized by higher amount of terpenoids. Green and herbaceous note was stronger in ogapiju than control group. Sensory evaluation indicated that good taste and palatability were highest in sample C.

• Korean Journal of Materials Research
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• v.3 no.2
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• pp.111-120
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• 1993

Abstract In this study, the Mo-Hf-O ingots containing 0.31-1.14at % Hf and 0.08-1.00at % 0 were prepared by plasma arc melting. The change of microstructure depending on the condition of heat treatmen~ was analysed by optical microscophy, auger electron microscophy, and transmission electron microscophy. Molybdenum powder with the oxygen content of 830ppm was compacted, and then melted. The oxygen content of molybdenum ingots was detected to be 40 -130ppm. As the contents of Hf and 0 increased, the grain size of ingots decreased. When molybdenum igot containing l.14at % Hf and 1.00at % C was heat treated, p-molybdenum carbide in grains was transformed into ${\alpha}$-molybdenum carbide at 130$0^{\circ}C$. Between 140$0^{\circ}C$ and 150$0^{\circ}C$, the precipitation of hafnium carbide was due to the reaction of solute Hf and C, and the hafnium carbide was saturated at grain boundaries at 150$0^{\circ}C$. When the sample was heat treated from 150$0^{\circ}C$ to 170$0^{\circ}C$, Hafnium oxide more stable thermodynamically precipitated both at grain boundaries and in grains after hafnium carbide had been dissolved at grain boundaries.

• Korean Journal of Environmental Agriculture
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• v.27 no.1
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• pp.66-71
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• 2008

Phosphorus transfer from agricultural soils to surface waters is an important environmental issue. Fly ash and phospho-gypsum which are industrial by-product were investigated as a means of reducing dissolved phosphorus in arable soil. To determine the optimum mixing ratio of fly ash(FA) and phospho-gypsum(PG) for reducing dissolved reactive P(DRP) in soil, various mixture ratio of FA and PG were mixed with two soil. The DRP content and pH in soils were analysed after 3 weeks incubation under flooding condition. Although DRP content in soils was significantly decreased by FA-PG mixture compared with control, there were no significant difference among the FA and PG mixture ratio of 75:25, 50:50, and 25:75. The mixture of 75% FA and 25% PG was selected for field test. A field experiment was carried out to evaluate the reducing DRP content in paddy soil to which 0(NPK), 20(FG 20), 40(FG 40), and 60(FG 60) Mg $ha^{-1}$ of the mixture were applied. The DRP content was reduced by 31% at the application rate of 60 Mg $ha^{-1}$. In contrast to deceasing DRP, Ca-P content increased significantly with the mixture application rate. After rice harvesting, available $SiO_2$, P, and exchangeable Ca content in soil increased significantly with application rate due to high content of Si, P, and Ca in the mixture. Mixtures of fly ash and gypsum should reduce P loss from paddy soil and increase soil fertility.

• Analytical Science and Technology
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• v.16 no.1
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• pp.1-11
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• 2003

This research examined the presence of hazardous materials in chemical workplace field using an integrated chemical/biological monitoring. Chemical workplace field air for volatile organic compounds (VOCs) analysis was collected using a collection tube packed with Tena.x TA adsorbent 400 mg. Workplace field air samples were analyzed by gas chromatography/mass spectrometry (GC/MS). Simultaneously, Tradescantia BNL 4430 clone was exposed in situ to monitor hazardous materials in chemical workplace field. GC/MS analysis showed the presence of various VOCs such as trichloroethylene, toluene, ethylbenzene, (m,p,o)-xylenes, styrene, 1,3,5-trimethylbenzene, and 1,2,4-trimethylbenzene. The results showed that in situ monitoring of VOCs with the Tradescantia-micronucleus (Trad-MCN) assay gave positive results in chemical workplace field and negative response at outdoor air. In conclusion, inhalation of these field air by workers may affect chronic demage to their health by inducing micronuclei formation in Tradescantia pollen mother cells. The combination of chemical/biological monitoring is very effective to evaluate hazardous materials in workplace field and can be alternatively used for screening hazardous materials.

• Nuclear Engineering and Technology
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• v.50 no.5
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• pp.665-672
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• 2018

A venturi scrubber is an important element of Filtered Containment Venting System (FCVS) for the removal of aerosols in contaminated air. The present work involves computational fluid dynamics (CFD) study of dust particle removal efficiency of a venturi scrubber operating in self-priming mode using ANSYS CFX. Titanium oxide ($TiO_2$) particles having sizes of 1 micron have been taken as dust particles. CFD methodology to simulate the venturi scrubber has been first developed. The cascade atomization and breakup (CAB) model has been used to predict deformation of water droplets, whereas the Eulerian-Lagrangian approach has been used to handle multiphase flow involving air, dust, and water. The developed methodology has been applied to simulate venturi scrubber geometry taken from the literature. Dust particle removal efficiency has been calculated for forced feed operation of venturi scrubber and found to be in good agreement with the results available in the literature. In the second part, venturi scrubber along with a tank has been modeled in CFX, and transient simulations have been performed to study self-priming phenomenon. Self-priming has been observed by plotting the velocity vector fields of water. Suction of water in the venturi scrubber occurred due to the difference between static pressure in the venturi scrubber and the hydrostatic pressure of water inside the tank. Dust particle removal efficiency has been calculated for inlet air velocities of 1 m/s and 3 m/s. It has been observed that removal efficiency is higher in case of higher inlet air velocity.

• Journal of Ginseng Research
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• v.45 no.3
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• pp.390-400
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• 2021

Background: We recently showed that gintonin, an active ginseng ingredient, exhibits antibrain neurodegenerative disease effects including multiple target mechanisms such as antioxidative stress and antiinflammation via the lysophosphatidic acid (LPA) receptors. Amyotrophic lateral sclerosis (ALS) is a spinal disease characterized by neurodegenerative changes in motor neurons with subsequent skeletal muscle paralysis and death. However, pathophysiological mechanisms of ALS are still elusive, and therapeutic drugs have not yet been developed. We investigate the putative alleviating effects of gintonin in ALS. Methods: The G93A-SOD1 transgenic mouse ALS model was used. Gintonin (50 or 100 mg/kg/day, p.o.) administration started from week seven. We performed histological analyses, immunoblot assays, and behavioral tests. Results: Gintonin extended mouse survival and relieved motor dysfunctions. Histological analyses of spinal cords revealed that gintonin increased the survival of motor neurons, expression of brain-derived neurotrophic factors, choline acetyltransferase, NeuN, and Nissl bodies compared with the vehicle control. Gintonin attenuated elevated spinal NAD(P) quinone oxidoreductase 1 expression and decreased oxidative stress-related ferritin, ionized calcium-binding adapter molecule 1-immunoreactive microglia, S100β-immunoreactive astrocyte, and Olig2-immunoreactive oligodendrocytes compared with the control vehicle. Interestingly, we found that the spinal LPA1 receptor level was decreased, whereas gintonin treatment restored decreased LPA1 receptor expression levels in the G93A-SOD1 transgenic mouse, thereby attenuating neurological symptoms and histological deficits. Conclusion: Gintonin-mediated symptomatic improvements of ALS might be associated with the attenuations of neuronal loss and oxidative stress via the spinal LPA1 receptor regulations. The present results suggest that the spinal LPA1 receptor is engaged in ALS, and gintonin may be useful for relieving ALS symptoms.

• The Korean Journal of Nuclear Medicine Technology
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• v.28 no.1
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• pp.57-69
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• 2024

Purpose: Quantitative analysis through count measurement in nuclear medicine planar images is limited by analysis techniques that are useful for obtaining various clinical information or by organ overlap or artifacts in actual clinical practice. On the other hand, the use of SPECT tomography images is quantitative analysis using volume rather than planar, which is not only free from problems such as projection overlap, but also has excellent quantitative accuracy. In the use of developing SPECT quantitative analysis technology, this study aims to compare the accuracy of quantitative analysis between ROI of the conventional planar images and VOI of the SPECT tomographic images in evaluating the count change happened by the volume change of the source. Materials and Methods: A ^99mTcO₄^- source(200.17 MBq) was filled with sterilized water in the syringe to create a phantom with an inner diameter volume of 60 cc, and a planar image and a SPECT image were obtained by reducing the volume by 15 cc (25%) respectively. ROI and VOI(threshold: 1~45%, 5% interval) were set for each image obtained to estimate true count and measure the total count, and compared with the preseted volumetric change rate(%). Results: When volume changes of 25%, 50%, and 75% occurred in the initial volume of 60 cc(100%) of the phantom, the average count changes of the measured planar image were 26.8%, 53.2%, 77.5%, and the average count changes of the SPECT image were 24.4%, 50.9%, and 76.8%. In this case, the VOI size(cm³) set showed an average change rate of 25.4%, 51.1%, and 76.6%. The highest threshold value for the accuracy of radioactive concentration by VOI size (average error -1.03%) was 35%, and the VOI size of the same threshold had an error of -17.1% on average compared to the actual volume. Conclusion: On average, the count-based volumetric change rate in nuclear medicine images was able to track changes more accurately using VOI than ROI, but there was no significant difference with relatively similar value. However, the accuracy of radioactive concentration according to individual VOI sizes did not match, but it is considered that a relatively accurate quantitative analysis can be expected when the size of VOI is set smaller than the actual volume.