• International Journal of Stem Cells
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• v.16 no.3
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• pp.293-303
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• 2023

Background and Objectives: The physiological oxygen tension in fetal brains (~3%, physioxia) is beneficial for the maintenance of neural stem cells (NSCs). Sensitivity to oxygen varies between NSCs from different fetal brain regions, with midbrain NSCs showing selective susceptibility. Data on Hif-1𝛼/Notch regulatory interactions as well as our observations that Hif-1𝛼 and oxygen affect midbrain NSCs survival and proliferation prompted our investigations on involvement of Notch signalling in physioxia-dependent midbrain NSCs performance. Methods and Results: Here we found that physioxia (3% O₂) compared to normoxia (21% O₂) increased proliferation, maintained stemness by suppression of spontaneous differentiation and supported cell cycle progression. Microarray and qRT-PCR analyses identified significant changes of Notch related genes in midbrain NSCs after long-term (13 days), but not after short-term physioxia (48 hours). Consistently, inhibition of Notch signalling with DAPT increased, but its stimulation with Dll4 decreased spontaneous differentiation into neurons solely under normoxic but not under physioxic conditions. Conclusions: Notch signalling does not influence the fate decision of midbrain NSCs cultured in vitro in physioxia, where other factors like Hif-1𝛼 might be involved. Our findings on how physioxia effects in midbrain NSCs are transduced by alternative signalling might, at least in part, explain their selective susceptibility to oxygen.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.5
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• pp.211-217
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• 2006

This analysis evaluated small and large temperature gradient effects on the FRP deck considering lightweight of FRP deck and ply orientations at the interface between steel girders and FRP deck. Finally, the analytical results shows the possible failure mechanism of FRP deck under various temperature changes and its corresponding index is suddenly varied depending on the rapid change of temperature on the deck plate.

• Journal of the Korean Institute of Rural Architecture
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• v.13 no.1
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• pp.37-44
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• 2011

The maintenance works for brick-structured buildings are a new field in Korea, and practical cases are yet inadequate so that such works may cause adverse effects of damaging the buildings after all. Therefore, this study has extracted a preservation technology believed to be most desirable in minimizing the damage to the original state of the buildings and preserving the value as the cultural assets through maintenance work details from 1986 to 2010 regarding brick-structured buildings designated as cultural properties. Firstly, a brick replacement method of using the brick used at the time of construction is efficient in replacement and repair of brick material for preserving value of cultural assets and minimizing damage of the original form. Secondly, use of lime mortar through material analysis is effective in repair of masonry joint and mortar but it is not used often due to high experimental cost. Finally, reinforcement of structure using a form for a building with severe damage is most efficient when considering additional problems. However, damage on the original form of a building can be minimized and value of a building can be preserved only when consideration on sufficient case analysis, materials to be used, and conditions of a building is supported.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.1
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• pp.106-114
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• 2006

Uses of geosynthetics as a reinforcing material for earth structures have ever increased due to their excellent economy. fine external appearance. and easy construction. In the current practice of geosynthetics. however, the lacks of the standardized method of evaluating the soil/geosynthetics friction properties and the inconsistency of conventional design methods develop confusion to the civil engineers. The purpose of site monitoring of the retaining wall reinforced by geogrids was to evaluate the applicability of existing design methods to, and performance of. CHAMSTONE wall system. Full scale field performance during and after construction was monitored by incorporating instrumentation including strain gauges on the geogrid and soil pressure cells. The difference of the reinforcing effects of geosynthetics embedded in the soil will be also investigated by comparing of the line and curve types of retaining wall reinforced by geogrids with block type facings.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.4
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• pp.135-144
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• 2006

In performing a risk analysis of structures under earthquakes, it is imperative to identify the vulnerability of structures associated with various damage stages considering structural properties, soil-structure interactions, site condition, and so on. In this paper, the method to derive a representative fragility curve of seismic isolated LRB(lead rubber bearing) bridges is proposed. In which, the curve is assumed log-normally distribution with two parameters. The risk analysis of seismic isolated LRB bridges considering earthquake effects such as PGA, PGV, SA, SV, and SI is also performed to assure the earthquake resisting capability of the structures. An practical way for constructing the representative fragility curves is also recommended combining fragility curves of structures.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.4
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• pp.153-159
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• 2006

Recently, the polymer is used as an admixture in the repair mortar, which contains various admixtures and mineral admixtures. In this study, the fresh and mechanical properties of repair mortar influenced by the types of polymers(classified as E.V.A.) and the range of polymer ratio were investigated. It was found that with increasing the ratio of polymer, mechanical properties(compressive strength, flexural strength, adhesive strength) of repair mortar is improved and drying shrinkage is increased.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.4
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• pp.375-380
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• 1998

Six Holstein heifer calves weaned at 45 days-of-age were randomly allocated into high daily gain (1.1 kg/d, HDG) and low daily gain (0.56 kg/d, LDG) groups, and were slaughtered at 170 kg of live weight. Energy intake level in the feeding period was 2.4 $\times$ maintenance in 105 days for HDG and 1.4 $\times$ maintenance in 216 days for LDG calves. Total length of the small intestine was identical between groups, but both weights of the pancreas and of the small intestinal mucosa were greater (p < 0.01) for HDG calves. Alpha-amylase, lipase, proteinase, and trypsin activities of the whole pancreas were higher (p < 0.05) in HDG calves. Disaccharidase activity of the whole small intestinal mucosa was also higher (p < 0.10) for HDG than for LDG calves. However, the enzymatic activities, expressed as per gram or per protein of the pancreas and the small intestinal mucosa, were not affected (p > 0.10) by the plane of nutrition. These results suggest that the digestive enzyme activity in the small intestine varies primarily with the weight of tissues synthesizing the enzyme.

• The Research Journal of the Costume Culture
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• v.6 no.2
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• pp.92-108
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• 1998

The purpose of this study was designed a) to examine the relative importance for college students' clothing disposal causes and their factor structure: b) to test the effects of gender, clothing satisfaction and family income on clothing disposal determinants; and c) to assess the relationship between clothing purchase determinants and overall clothing satisfaction and clothing disposal determinants. Data (n=660) were collected from college students in Cheju Do. The survey questionnaire composed of a revised Clothing Disposal Determinants Scale, Clothing Purchase Determinants Scale and background variables. First, the most important reasons for clothing disposal were to unfit with body change, get washed our and raise nap on clothe, wornout with long-term use, do not ware for new purchasing clothe, uneasy on wear. Second, factor analysis of the revised Clothing Disposal Determinants Scale revealed five factors; unfitness, fashion change, quality dissatisfaction, product efficiency decrement, and maintenance/inconvenience. Third, female students perceived significantly higher in fashion change and unfitness than male students. Forth, unfitness and product efficiency decrement were significantly discriminated between between clothing satisfaction groups, unfitness and fashion change variables were significantly discriminated between family income groups. fifth, impulsive purchase factor was the best predictor of composite clothing disposal measure, followed by individuality, clothing satisfaction, practicality. The best predictors of each disposal factors were individuality oriented purchasing criterion in unfitness factor. Fashion in fashion change, impulsive purchase in quality dissatisfaction and product efficiency decrement factors, and practicality in maintenance/inconvenience factor. As a whole, the most consistent predictor of clothing disposal determinants was impulsive purchase factor.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.13 no.3
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• pp.409-418
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• 2006

Purpose: This study was done to identify the process of change, decisional balance and self-efficacy corresponding to stage of exercise behavior based on the Transtheoretical model in patients with chronic arthritis. Method: The participants were 151 patients with chronic arthritis using an out-patient pain clinic and hospital in C city. The collected data were analyzed using ANOVA, Sheffe test and discriminant analysis with SPSS/WIN. Results: The patients were distributed as follows for each stage of exercise behavior 21.8% in the precontemplation stage, 26.5% in the contemplation stage, 25.2% in the preparation stage, 7.3% in the action stage, and 19.2% in the maintenance stage. Significant effects for stage of change were found for nine of the 10 processes of change and Pros, Cons, self-efficacy. Scores on these variables were found to increase across the stage of exercise behaviors from precontemplation to maintenance. Discriminant analysis revealed that self-efficacy and stimulus control, and reinforcement management were the major correlates of the stage of exercise behaviors. Conclusion: The findings of this study give useful information for exercise intervention, by using strategies of exercise for chronic arthritis patients in different stages of exercise behavior.

• Journal of Korean Society of Transportation
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• v.24 no.3 s.89
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• pp.189-195
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• 2006

For the past decades, vehicle emissions has been a major source of air pollution in urban areas Vehicle inspection and maintenance (I/M) test programs were developed for major metropolitan areas to reduce urban air pollution. However. there are a few studies of exploring major factors to influence I/M test failure. This study develops a logit model to identify key factors affecting overall test failure, using the vehicle I/M test data from California in October 2002. The model results indicate that vehicle age, odometer reading, engine size, vehicle make, presences of emissions control equipment, and test types have significant effects on the probability of I/M test failure.