• Journal of Plant Biotechnology
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• v.32 no.3
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• pp.151-159
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• 2005

Injury caused by reactive oxygen species (ROS), known as oxidative stress, is one of the major damaging factors in plants exposed to environmental stress. Chloroplasts are specially sensitive to damage by ROS because electrons that escape from the photosynthetic electron transfer system are able to react with relatively high concentration of $O_2$ in chloroplasts. To cope with oxidative stress, plants have evolved an efficient ROS-scavenging enzymes such as superoxide dismutase (SOD) and ascorbate peroxidase (APX), and low molecular weight antioxidants including ascorbate, glutathione and phenolic compounds. To maintain the productivity of plants under the stress condition, it is possible to fortify the antioxidative mechanisms in the chloroplasts by manipulating the antioxidation genes. A powerful gene expression system with an appropriate promoter is key requisite for excellent stress-tolerant plants. We developed a strong oxidative stress-inducible peroxidase (SWPA2) promoter from cultured cells of sweetpotato (Ipomoea batatas) as an industrial platform technology to develop transgenic plants with enhanced tolerance to environmental stress. Recently, in order to develop transgenic sweetpotato (tv. Yulmi) and potato (Solanum tuberosum L. cv. Atlantic and Superior) plants with enhanced tolerance to multiple stress, the genes of both CuZnSOD and APX were expressed in chloroplasts under the control of an SWPA2 promoter (referred to SSA plants). As expected, SSA sweetpotato and potato plants showed enhanced tolerance to methyl viologen-mediated oxidative stress. In addition, SSA plants showed enhanced tolerance to multiple stresses such as temperature stress, drought and sulphur dioxide. Our results strongly suggested that the rational manipulation of antioxidative mechanism in chloroplasts will be applicable to the development of all plant species with enhanced tolerance to multiple environmental stresses to contribute in solving the global food and environmental problems in the 21st century.

• Journal of Preventive Medicine and Public Health
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• v.26 no.1 s.41
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• pp.147-164
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• 1993

A study has been conducted on developing questionnaires to serve as on site diagnostic tools for the early detection of neuropsychiatric impairment among workers chronically exposed to low-level organic solvents. Two drafts of tentative questionnaires have been developed as follows; several question items were selected from questionnaires which were administered to workers exposed to organic solvents in previous studios and were grouped into each symptom category based on the presence of its association using Guttman scaling method, then these selected items were reviewed by neuropsychiatry specialists. The final draft of the questionnaire (total symptom score=36) was developed by selecting 33 question items which had more than a 0.88 Guttman coefficient of reproducibility in each symptom category from a pilot study in which these tentative questionnaires were administered to workers manufacturing soles. Three plants using organic solvents and one plant never using organic solvents as a control group were selected to test the reliability and validity of the developed questionnaires. The major organic solvent in the workplace environment detected by a personal air sampler and GC/MSD nab toluene. The concentration of toluene in air from the department using organic solvent was statistically different from that of the department never using organic solvent. The concentration of toluene from almost all of the workplace did not exceed the allowable level. There was no statistically significant difference between the concentration of urinary hippuric acid from the workers of the department using organic solvent and that of the department never using it. Total symptom score of the plant never using organic solvents was 9.8 and those of the three plants using organic solvents were 15.6, 14.7, and 13,7 respectively. In order to evaluate the validity of the questionnaires, the workers from two different departments of the plant in which usage of organic solvents are totally dofferemt were compared. The total symptom score was 17.8 for workers of the department using organic solvent and 13.5 for the department never using organic solvent and scores of each symptom group between exposure and non-exposure group also showed statistically significant difference. The finding that total symptom score of the exposure group increased as the duration of employment increased indirectly suggests the usefulness of the developed questionnaire to assess the health effects of chronic exposure to organic solvents. The correlation coefficient, which was calculated to evaluate the test-retest reliability, was 0.581 (p=0.001). The coefficient of Crohnbach which reflects the internal consistency of the questionnaire was 0.91. In conclusion, the reliabilty of the questionnaire was well maintained over the time lapse between the two administrations of the questionnaire and despite the seasonal difference.

• Information Systems Review
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• v.13 no.1
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• pp.33-59
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• 2011

Although online social network services widely used in human networking and recruiting industries, it is showing off its limitations in followings-it's hard to reach the status of seamless connection between offline and online; the incompletion and low credibility of the information came from non-face-to-face profile exchange; and the restraint of user autonomy due to centralized control. This paper defines the ubiquitous social network management which enables the seamless real-time face-to-face social interactions of the users based on WPAN (Wireless Personal Area Network) who share the same interest in real word and deduces a ubiquitous social network management framework based on it. As an instance of ubiquitous social network management, u-Recruiting service model will be designed and analyzed. The Analysis using the business model will be followed by the possible scenario of service model. The role, value proposition and potential benefits of the each participants in this service model and will be given as well. In order to evaluate relative advantages of the model suggested by this study, 6 cases will be compared.

• Korean Journal of Ecology and Environment
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• v.46 no.3
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• pp.343-359
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• 2013

In order to understand shoreline environment characteristics of Korean reservoirs, the interrelationships between environmental factors of geomorphology, hydrology, water quality and shoreline soil were analyzed, and the reservoir types were classified according to their environmental characteristics in the 35 reservoirs selected by considering the purpose of dam operations and annual water-level fluctuations. Geomorphological and hydrological characteristics of reservoirs were correlated with the altitude and the size scale of reservoirs. The annual range of water level fluctuation showed a wide variation from 1 m to 27 m in the various reservoirs in Korea. The levels of eutrophication of most reservoirs were mesotrophic or eutrophic. From the result of the soil texture analysis, sand contents were high in reservoir shorelines. Range, frequency and duration of water-level fluctuation were distinctive from the primary function of reservoirs. Flood control reservoirs had a wide range with low frequency and waterpower generation reservoirs had a narrow range with high frequency in the water-level fluctuation. According to the result of CART (classification and regression tree) analysis, the water quality of reservoirs was classified by water depth, range of water-level fluctuation and altitude. The result of PCA (principal component analysis) showed that the type of reservoirs was classified by reservoir size, water-level fluctuation, water quality, soil texture and soil organic matter. In conclusion, reservoir size, the water-level fluctuation, water quality and soil characteristics might be major factors in the environment of reservoir shorelines in Korea.

• Journal of the Korean Society for Library and Information Science
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• v.25
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• pp.83-150
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• 1993

Traditionally, the emphasis of the information services had been placed on the information provider's knowledge of information sources or information systems. However, in view of the increasing complexity of the information environment. and changes taking place in information professions the evaluation of the information services has callded for further research in interpersonal communication aspects of the librarian user interface especially that which links to user satisfaction. This experimental study was carried out for the purpose of exploring the implications of nonverbal behaviors in measuring user satisfaction in the light of the fact that the meaning of nonverbal clues includes more than verbal communication especially in dealing with variable barriers even though they operate at low levels of awareness. In this sense, among the wide range of nonverbal communication areas in particular kinesics, artifacts and the proximics were examined to suggest alternative model which can be applied effectively in our specific set of information work environment. Two major university libraries and two research libraries in Korea were chosen and visited for the anlysis and per each refernce/information interview the librarian's nonverbal behaviors were checked on the observer's checklist and the qustionnaires completed by the user at a time. On the basis of these data firstly, the relation of user satisfaction concerned with the librarian's nonverbal communication to user satisfaction with information services was analyzed and the possible communication barriers were investigated. In addition, the effect of training the information librarian with positive nonverbal communication skills on the user's satisfaction was analyzed in a SAS computer program in the area of kinesics. On the other hand, the effect of other nonverbal behaviors such as proximics and artifacts known very important clues to improving a complex human interaction was discussed along with their experimental results. In conclusion, it was found that most of users were not sensitive to the importance of nonverbal behaviors exposed by the information librarian, but it was proved that the ultimate user satisfaction and the satisfaction of the librarian's nonverbal behaviors are correlated positively, Moreover, nonverbal behaviors displayed by the trained librarian toward the user had a considerable effect on the user's evalution of information services compared with those by the untrained. These findings imply that in order to control the librarian's nonverbal behaviors and to help the user overcome his barriers the information librarian as a specialist needs to assure and modify willilingly his communication behavior. Without making effective use of such nonverbal communication, information librarian could not expect to meet the user's information needs either. However, when these positive nonverbal behaviors are applied it would be highly desirable to be aware of cultural and contextual differences. With regard to increasing information services success the applicable nonverbal communication model for library management and education can be suggested as below.

• Fire Science and Engineering
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• v.26 no.3
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• pp.106-111
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• 2012

In this study, EIFS (Exterior insulation finish system) of exterior cladding was applied Cone calorimeter test to confirm the effect of flame retardant. As a results, the initial ignition points in accordance with the coated form and concentration of the flame retardant was delayed. But flame resistant treatment of EIFS cladding to control the fire will not affect confirmed that. In addition, EIFS that uses high-density and low-density due to difference in the density of the impact of the fire was no difference. The exterior of the ignition experiment occurred before and after 40 seconds, heat release rate to 100 seconds appears to occur about 90 % compared with the other exterior wall materials, the initial fire spread very fast was confirmed. EIFS cladding in order to prevent the spread of fire in the application of EIFS legally use is limited by the use of the building. And flame spread can be prevented, such as a vertical outer wall compartment measures are urgently needed.

• Korean Journal of Plant Tissue Culture
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• v.24 no.6
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• pp.361-367
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• 1997

This study was carried out to select cadmium resistant cell lines from leaf-derived calli of diploid and haploid of Nicotiana tabacum cv. BY4, for understanding adaptation mechanism of plants in cadmium contaminated environment. suspended cell clumps were plated onto selection medium containing 0 to 2,000 $\mu$M cadmium. Cadmium resistant colonies were formed on the selection medium after 3 or 4 weeks of culture. The minimum inhibition concentration (MIC) of cadmium on colony formation were 300 $\mu$M in diploid and 200 $\mu$M in haploid plants, respectively. In order to test the resistance to cadmium, selected cell line on MIC were transferred to medium containing high concentration of cadmium. The selected cell lines, especially haploid cell line, were resistant an the high concentration of cadmium. And dry weight, ash weight, and cadmium contents of cell were increased. These results indicated that the selected cell lines showed higher resistance of cadmium than control cells, and haploid plant is more resistant than diploid plant on medium with cadmium.

• Journal of Pharmaceutical Investigation
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• v.36 no.4
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• pp.271-276
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• 2006

Felodipine, a calcium-antagonist of dihydropyridine type, is a poorly water soluble drug and has very low bioavailability. As preceding studies, use of solid dispersion systems and surfactants(solubilizers) has been suggested to increase dissolution and to improve bioavailability of felodipine. But in case of solid dispersion systems, large amount of toxic organic solvents should be used and manufacturing process time become longer than conventional process. In case of using surfactants, as time elapsed, decreasing of dissolution rate of felodipine due to crystallization has been reported. In this study, Copovidon as a hydrophilic polymer and $Transcutol^{\circledR}$ as a surfactant were combined to formulations if order to increase dissolution of felodipine and conventional wet granulation process were applied to manufacturing of formulations. The effect of Copovidon and $Transcutol^{\circledR}$ on the dissolution oi felodipine was investigated in-vitro. When Copovidon and $Transcutol^{\circledR}$ used simultaneously, the dissolution rate of felodipine was prominently increased compared with when used separately and the maximum increase in the dissolution of felodipine was 5.8 fold compared to control. This is most probably due to synergy effect by combination of Copovidon and $Transcutol^{\circledR}$. Felodipine sustained release tablets were successfully formulated using several grades of HPMC as a release retarding agent. The stability of felodipine sustained release tablet was evaluated after storage at accelerated condition($40^{\circ}C/75%\;RH$) for 6months in HDPE(High density polyethylene) bottle. Neither significant degradation nor change of dissolution rate for felodipine was observed after 6months. In conclusion, felodipine sustained release tablet was successfully formulated and dissolution of felodipine, poorly water soluble drug, was prominently increased and also stability was guaranteed by using combination system of hydrophilic polymer and surfactant.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5550-5558
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• 2015

Recently, fuel cell with high energy efficiency and low CO2 emission is energetically interconnected with power system. Especially, FCGS(Fuel Cell Generation System) which usually operates at high temperature, is being developed and installed in the form of large scale system. However, it is reported that power system disturbances related to surge, harmonic and EMI have caused several problems such as malfunction of protection device and damage of control device in the large scale FCGS. In order to solve these problems, this paper presents a modeling of operation characteristics of FCGS by PSCAD/EMTDC, ETAP, P-SIM software. And also, this paper proposes countermeasure algorithms to prevent power system disturbances. From the simulation results, it is confirmed that the proposed algorithm is useful method for the stable operation of large scale FCGS.

• Horticultural Science & Technology
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• v.28 no.5
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• pp.902-911
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• 2010

Oriental melon ($Cucumis$ $melo$ var. $makuwa$) is a popular and high-value market fruit cultivated in Korea. Consumers are becoming increasingly interested in oriental melon as a healthy diet over the past few years. However, the melons have relatively high quality loss because the fruit are mainly produced for a limited period of time in the summer season. Lack of the proper postharvest treatments and high temperature exposure at harvest or during distribution are the most critical environmental factors limiting postharvest life of fruit. This review focuses on the overview of current research studies for postharvest treatment and functional packaging technology of oriental melon in Korea. Major physiological problems of the harvest fruit include the ripening process in quality changes of the produce such as loss of weight, firmness, flavor, and decay during the storage periods. Low temperature at 7 to $10^{\circ}C$ with high relative humidity of 90 to 95% is the suitable environmental condition used to maintain the quality of fresh oriental melon. Controlled atmosphere (CA) storage or modified atmosphere (MA) packaging can be used as supplemental treatments to extend postharvest-life. For oriental melon, an optimum CA is currently recommended to be 2-3% oxygen and 5-10% carbon dioxide atmosphere. Precooling, pretreatments of ethylene action and functional packaging system can be applied to oriental melon after harvest in order to extend storage life. Major active packaging technologies are concerned with a selectively gas permeable film related to respiration of produce and the packaging applications of ethylene removal, antimicrobial, and antifogging substances to keep the effective freshness of fruit.