• BMB Reports
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• v.39 no.1
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• pp.55-60
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• 2006

We describe a phage display strategy, based on the differential resistance of proteins to denaturant-induced unfolding, that can be used to select protein variants with improved conformational stability. To test the efficiency of this strategy, wild-type and two stable variants of ${\alpha}_1$-antitrypsin (${\alpha}_1AT$) were fused to the gene III protein of M13 phage. These phages were incubated in unfolding solution containing denaturant (urea or guanidinium chloride), and then subjected to an unfavorable refolding procedure (dialysis at $37^{\circ}C$). Once the ${\alpha}_1AT$ moiety of the fusion protein had unfolded in the unfolding solution, in which the denaturant concentration was higher than the unfolding transition midpoint ($C_m$) of the ${\alpha}_1AT$ variant, around 20% of the phage retained binding affinity to anti-${\alpha}_1AT$ antibody due to a low refolding efficiency. Moreover, this affinity reduced to less than 5% when 10 mg/mL skimmed milk (a misfolding-promoting additive) was included during the unfolding/refolding procedure. In contrast, most binding affinity (>95%) remained if the ${\alpha}_1AT$ variant was stable enough to resist unfolding. Because this selection procedure does not affect the infectivity of M13, the method is expected to be generally applicable to the high-throughput screening of stable protein variants, when activity-based screening is not possible.

• The Journal of the Korea Contents Association
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• v.13 no.11
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• pp.1-10
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• 2013

With the help of information technology, PVR has been evaluated as an innovative device that brings epochal changes for program selection and convenience of receivers with the convergence between broadcasting and telecommunication. Satellite broadcasters introduced PVR service to strengthen its interactive function. This study analyzed PVR user behavior and how it changed the existing TV viewing behavior through satellite subscribers. The results revealed that PVR subscribers mainly used it for time shifting like VCR use. FUrthermore, heavy PVR users watched TV more than on average and enjoyed a divers genre of programs. This study provides scholarly implication for PVR using behavior and its effects and its useful information for contents and marketing strategy to help PVR service popularization.

• Clean Technology
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• v.24 no.1
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• pp.63-69
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• 2018

The reduction reaction characteristics and physicochemical properties were studied for the selection of oxygen carrier, which is the core of the chemical looping combustion (CLC) technology. Fuel conversion and $CO_2$ selectivity of oxygen carrier according to the concentration of reducing gas and the reduction temperature using three kinds of oxygen carrier (SDN70, N018-R2, N016-R4) were measured and compared. In addition, Attrition Index (AI) and BET surface area were measured to analyze the attrition resistance and the surface characteristics of the oxygen carrier. As a result, it was confirmed that all three kinds of oxygen carrier were suitable for use in chemical roofing combustion system, and the best particle was determined to be N016-R4.

• Communications of Mathematical Education
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• v.24 no.3
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• pp.563-585
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• 2010

The major goals of this study are to find the factors that enhance self-directed math learning in college math classes and to provide the students with the opportunities to check and develop their self-directed math learning attitude. For these research goals, we prepared the questionnaires that asked about their learning motivations, basic learning ability, self-discipline strategies, and self-directed learning strategies. Another purpose of the questionnaires was to give them the chances to check and improve their attitude toward those learning strategies, motivation and ability. From the research results, we find that the important factors for self-directed learning are internal & external motivations, concentration ability, and the goal-setting and plan-making abilities. In addition, concentration ability, good habit, stress-control, recognition of math value, and self-directing ability are found to be necessary for the desirable learning environment. On the other hand, we find that the ability to perform note-taking, class preparation and review, time-control, and test-control is required for the selection and practice of self-fitting learning strategies. Finally, we provided our own self-directed math learning model. Our model, containing the necessary factors for self-directed math learning, is the revised and modified one of Knowles(1975)'s 5 stage self-directed learning model that comprises diagnosis of learning desire, setting learning goals, grasping human&material resources, selection and practice of proper learning strategies, and evaluation of learning results.

• Journal of Cadastre & Land InformatiX
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• v.48 no.2
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• pp.185-195
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• 2018

In the Seoul Metropolitan City, the PM(pariculate matter) application used by the citizens provides the PM concentration of the nearest monitoring stations located on the PM monitoring stations. Currently, the selecting method of the PM monitoring network considered by the Ministry of Environment is based on considering the monitoring station distribution and population density only. In this study, we analyzed the distance between PM monitoring station and the administrative center point in addition to the above considerations. The number of test sites was verified and the range of coverage of each monitoring stations was indicated by using the Voronoi algorithm and hexagon grid. The spatial position problem of the PM monitoring station was suggested by spatial data analysis. The variables of spatial data analysis are single-family houses, apartments, $1^{st}$ class neighborhood, $2^{nd}$ class neighborhood, garbage disposal plant, hazardous material disposal facility, factory, and the density map. The analysis result of the selection criterion considering the additional variables for new PM monitoring stations was presented, in addition to the selection criteria provided by the Ministry of Environment.

• Journal of Korean society of Dental Hygiene
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• v.22 no.4
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• pp.231-240
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• 2022

Objectives: This study was conducted to survey the currently available fluoride-containing oral hygiene products in Korea to provide consumers with information regarding the concentration and form of fluoride in each product, as well as to determine whether the information was easy to understand. Methods: A total of 64 types of domestic commercial oral hygiene products were purchased from an offline market and evaluated. Results: The domestic commercial toothpaste products contained fluoride in the form of sodium fluoride (NaF) and sodium monofluorophosphate (SMFP). In this study, toothpaste containing 1,000 ppm fluoride compounds accounted for the largest proportion (61.5%). Toothpastes containing below 1,000 ppm fluoride accounted for 34.6%, while toothpastes with fluoride above 1,000 ppm fluoride accounted for 3.9%. Toothpaste containing more than 1,000 ppm fluoride has not been popularized domestically. Mouthwash products contained fluoride compounds at less than 300 ppm concentration. Of the five types of mouthwash products, only two types had labels indicating fluoride concentration. In addition, the location of the labels indicating fluoride concentration differed between manufacturers and even within the same manufacturer. Conclusions: It is important to popularize toothpaste with fluoride levels above 1,000 ppm so that a broader selection of toothpaste can be offered to consumers in need. Standardized information needs to be provided for consumer convenience to aid in choosing appropriate oral hygiene products.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.8
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• pp.802-808
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• 2010

This study was carried out to apply the method of priority order selection for water quality improvement of watershed. The monitoring of flow and water quality, grouping branch streams and discharge load density were estimated on 18 branch streams located in middle and lower area of Geum River, Chungcheongnam-do. Based on average BOD concentration of stream at low flow, the results of the water quality analysis of stream which excess river living standard class 2 (less than BOD 3 mg/L) are Jeongancheon, Bangchukcheon, Gilsancheon, Jocheon, Seokseongcheon and Ganggyeongcheon. As a result of grouping stream, stream that have more than $10\;m^3/min$ of flow and more than 3.0 mg/L of average BOD concentration such as Group A are Jocheon, Seokseongcheon, Ganggyeongcheon and Jeongancheon. In Group A, stream corresponds to over than discharge load density as of 10 BOD kg/$day{\cdot}km^2$ is Jocheon, Seokseongcheon and Ganggyeongcheon. In view of the selected results to improve water quality basin through monitoring of flow and water quality, grouping stream, and estimation of discharge load density, Jocheon in Yeongi, Seokseongcheon located on the border of Buyeo and Nonsan, Ganggyeongcheon on Nonsan such as stream basin were urgent to improve water quality.

• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.1
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• pp.13-25
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• 2005

In general, tunnel ventilation is analyzed with the assumption of equal vehicular speed for both directions in bidirectional traffic tunnels. This practice is likely to result in minimizing the piston effects and cannot take into consideration the effects of real situations, since in most cases, speeds of vehicles moving in opposite directions are not equal. Therefore, The ultimate goal of this study is to review the effects of unequal vehicular speeds on the planning of local bidirectional tunnel ventilation. To apply unequal vehicular speed for the bidirectional tunnel ventilation plan, the following requirements are necessary; (1) Adoption of strict smoke concentration standards for 'free-flow & congested' traffic conditions, (2) Selection of an appropriate ratio of heavy directional traffic volume, and (3) Selection of reasonable stepwised magnitude of speed difference. Based on the importance of research topic, this study aims at comparing the differences of the capacity of ventilation equipment for the cases with equal and unequal vehicular speeds in local bidirectional tunnels.

• Journal of Gifted/Talented Education
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• v.20 no.1
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• pp.131-150
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• 2010

This research was planned to analyze the students' science writing tendencies according to the level of meta-cognition for using as materials of selection of gifted students. To get results, meta-cognition writing tests which measured critical thinking ability and problem solving ability were developed, and the students' the level of meta-cognition was measured. Thereafter We analyzed the students' science writing tendencies in accordance with the level of meta-cognition through the science writing with meta-cognition task(the main theme are expectation; explanation; claim; criticism; imagination), and found out the students' ability of science writing was different with the level of meta-cognition. Students with the low level meta-cognition did not represent their thinking well, but students with the high level meta-cognition were try to upgrade their writing through highly concentration and perceiving theirs writing mistakes. As this results, science writing is useful as materials of selection of gifted students.

• Journal of Conservation Science
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• v.9 no.1
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• pp.40-47
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• 2000

Dimension stability was examined after PEG pretreatment and post freeze-drying treatment in order to determine the PEG(#3350) concentration and solvent for pre-treatment of freeze-drying of highly-degraded waterlogged ash woods(Fraxinus spp.; ca. 5,700 BP) excavated from peat lands at Pyungtack, Kyounggi-do. At the low concentration (<30-40%) of PEG soaking in both water and t-butanol, the weight increases abruptly, but at high concentration (>50%) gradually, consequently, taking longer treatment time. PEG loading was higher in t-butanol solution than in water. However, the best dimesional stability was obtained from freeze-drying after lower PEG solution (40% in water) soaking. Low dimensional stability, found in the samples treated with higher PEG solutions (60%-70% in t-butanol), might come from incomplete freezing and excess PEG absorbing moisture. The samples air-dried after 70% PEG treatment had collapse defects. In conclusion, the use of low concentration (about 40% in water) PEG solution was the most suitable pretreatment for freeze drying of highly-degraded waterlogged ash woods.