• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.1
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• pp.17-22
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• 2000

The separation of tryptophan enantiomers was carried out with medium-pressure liquid chromatography using BSA (bovine serum albumin)-bonded silica as a chiral stationary phase. The influence of various experimental factors such as pH and ionic strength of mobile phase, separation temperature, and the presence of organic additives on the resolution was studied. In order to expand this system to preparative scale, the loadability of sample and the stability of stationary phase for repeated use were also examined. The separation of tryptophan enantiomers was successful with this system. The data indicated that a higher separation factor (a) was obtained at a higher pH and lower temperature and ionic strength in mobile phase. Addition of organic additives (acetonitrile and 2-propanol) in mobile phase contributed to reduce the retention time of L-tryptophan. About $30\%$ of the separation factor was reduced after 80 days of repeated use.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.87.2-87
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• 2003

Long-term repeated culturing of biocontrol agents on a certain medium often results in reduced biocontrol efficacy and altered physiology. Effect of culturing media on biocontrol ability and physiological state of Burkholderia gladioli strain B543 was investigated. Over 20 times repeated cultivation of B. giadioli strain B543 on Kings B medium or nutrient agar medium showed improved biological control of cucumber damping-off caused by Pythium ultimum, while one time cultivation on KB or NA did not. The repeated cultivation also induced the physiological changes of the biocontrol agent such as antifungal activity and the production of protease and siderophore. Our result indicates that adaptation to proper culturing medium can alter biocontrol ability and must consider in optimizing the use of biocontrol agents.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.10 no.1
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• pp.7-13
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• 2012

Purpose : This study was conducted to examine the effects of unstable surface training and galvanic vestibular stimulation on balance and proprioception. Methods : 4-week training was applied to 40 normal adults in their twenties (unstable surface training group 10, galvanic vestibular stimulation group 10, unstable surface training and galvanic vestibular stimulation group 10, control group 10). Balance and proprioception was measured before the experiment, after two weeks, and after four weeks. Repeated ANOVA was used for balance and proprioception analysis. Results : As a result of repeated ANOVA on balance changes in double support, a significant difference was found in open sight in interaction among groups and periods (p<0.05). As a result of repeated ANOVA on balance changes in double support, there was a significant difference in closed sight and interaction among groups and periods (p<0.05). As a result of repeated ANOVA on balance changes in proprioception, there was no statistically significant difference in interaction among groups and periods. Conclusion : In conclusion, both unstable surface training and galvanic vestibular stimulation had positive effect on balance control and proprioception improvement, and their excellence was not greatly different. Thus, it is possible to use unstable surface training and galvanic vestibular stimulation for physical therapy intervention to improve balance and proprioception. Since the results showed that simultaneous application of two methods had greater effects on difference compared with a single application, it is suggested to use this intervention in the clinical field.

• Environmental Analysis Health and Toxicology
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• v.16 no.2
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• pp.43-50
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• 2001

A daily newspaper in Korea addressed an controversial issue recently that the concentration of radon measured from the groundwater in Taejon was found out a relatively high level. The cancer risk arising from ingestion of such radon should be derived from calculation of the dose absorbed by the tissues at risk. The study performed by the National Research Council in United States confirmed that the use of a PBPK model for the ingested radon could provide the useful information regarding the distribution of radon among the organs of the body. This study presents an approach for the internal dose assessment of ingested radon for this case. At first, the study develops a PBPK model for ingested radon. However, the important issue is how to simulate a more realistic situation using the model associated with repeated oral doses rather than a single oral dose. The simulations are performed for repeated oral exposures per 8-hour interval using the PBPK model for a male adult. The concentration and cumulative value of radon concentration are calculated and analyzed for lung tissue and adipose group, respectively. The results could be used for the realistic prediction of the internal dose of radon in the human body for repeated oral exposures.

• Journal of the Korean Society of Clothing and Textiles
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• v.41 no.3
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• pp.527-536
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• 2017

This study investigated the detergency and functionality of laminating finished fabrics for outdoor wear based on repeated washing. Laminating finished fabrics were selected as the main fabrics for outdoor wear and used as test fabrics. The effects of outdoor exclusive detergent and normal neutral detergent were examined according to washing time, temperature, rpm and detergent concentration based on the use of a Terg-O-Tometer. Re-soiling of the test fabrics was measured by Florio-Mersereau. Permeability, water repellency, water resistance and absorbency were estimated to measure improvements and effects in regards to outdoor exclusive detergent in optimal washing conditions. The detergent effect of outdoor exclusive detergent was superior compared to normal neutral detergent. Re-soiling was lower with exclusive outdoor detergent than with normal neutral detergent. The measurement of functionality for laminating finished fabrics before and after washing indicated that functionality was decreased with repeated washing.

• International Journal of Highway Engineering
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• v.8 no.3 s.29
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• pp.21-28
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• 2006

Field or laboratory wheel tracking tests have been employed for the evaluation of the rutting potential of asphalt paving mixtures. Compared to field tests, laboratory wheel tracking tests are much less expensive and more manageable for most road projects. However, most test laboratories are not equipped to perform such tests because there does not exist any standard test procedure, and the required equipment is rather expensive. Futhermore, the size of test specimens and the relatively large quantity of test mixture required present difficulties for laboratory specimen mixing and compaction. This paper describes a project conducted to study the feasibility of replacing wheel tracking testsby a repeated-load creep test for rutting potential evaluation. Comparisons were made between the results of the two tests for different test temperatures, loading speeds and applied pressures. Three types of asphalt mixtures were studied in the test program. Favorable conclusions concerning the use of the repeated-load test for rutting potential evaluation were drawn based on the findings of the experimental test results. The correlation between the two types of tests was found to be good for all threeasphalt mixtures. Adopting the repeated-load creep test would lead to cost savings since it employs standard test equipment already available in most laboratories. It would also result in substantial time savings due to the much smaller quantity of mix needed, and the ease in specimen preparation.

• The Journal of the Korea Contents Association
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• v.17 no.1
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• pp.692-700
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• 2017

Based on the sexual offenses committed in school, the present study investigated differences between habitual/repeated sexual offenses and one-off sexual offenses in terms of offender characteristics, victim characteristics, and offense characteristics. We examined a total of 218 sexual offense cases committed in school. As a result, we found significant differences in the age, job, and residential area between habitual/repeated and one-off sexual offenders in school. In addition, notable differences were found between habitual/repeated and one-off sexual offense cases in the age and alcohol use of the victim. Moreover, habitual/repeated and one-off sexual offenses in school differed significantly by offense planning, method of approaching the victim, type of sexual behavior, and victim resistance. Furthermore, we conducted regression analyses and identified multiple factors that contributed to lasting of the sexual offense in school. Finally, we discussed limitations of the present study and made suggestions for future research.

• Journal of the Korean Society of Radiology
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• v.9 no.7
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• pp.509-513
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• 2015

In this study, we evaluated the thermal denaturation characteristics of reusable NIPAM tissue mimicking (TM) Phantom by measuring the thermal sensitivity. And the changes of acoustic characteristic and thermal denaturation shape in NIPAM TM phantom according to the number of re-use time and re-use period were observed. With the result, as the sonication time is increased, the sound velocity of NIPAM phantom was decreased by 100 m/s and the attenuation was increased slightly. However, the changes according to the re-use period was not observed. In the thermal denaturation shape and size observation by ultrasound sonicaton, the remarkable changes have not been confirmed. With the result of this study, NIPAM Phantom was considered appropriate to evaluate and predict the effect of therapeutic ultrasound by in repeated sonication test.

• Biomolecules & Therapeutics
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• v.19 no.1
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• pp.45-51
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• 2011

These experiments were designed to use typical makers from behaviors and molecular basis in addicted animals of morphine and cocaine. Morphine has been widely abused with a high physical dependence liability. Morphine withdrawal activates the intracellular cAMP signaling pathway and further leads to changes in the expression of the cAMP response element binding protein (CREB), which may be important to the development and expression of morphine dependence. From these experiments, repeated morphine (10 mg/kg, twice per day for 7 days) developed physical dependence. Withdrawal signs were precipitated by naloxone and also increased the expression of the CREB. In addition, repeated exposure of cocaine (15 mg/kg) to mice develops locomotor sensitization and produced lasting behavioral sensitivity. Cocaine- and amphetamine-regulated transcript peptide (CART) peptide was up-regulated by repeated administration of cocaine in the striatum. Therefore, repeated morphine induced the development of physical dependence and increased pCREB. In addition, repeated cocaine induced locomotor sensitization and over-expressed CART peptide. In conclusion, the development of physical dependence and pCREB for morphine, and locomotor sensitization and CART peptide over-expression for cocaine would be useful markers to predict the abuse potential of opioid analgesics and pychostimulant drugs in animals, respectively.

• Journal of Technologic Dentistry
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• v.43 no.4
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• pp.175-180
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• 2021

Purpose: This study investigates the effect of repeated use of lithium disilicate glass-ceramics on color stability. Methods: In this study, 2 types of lithium disilicate glass-ceramics were used and they were divided into 4 groups after 1st, 2nd, 3rd, and 4th heat pressing. The L^*, a^*, and b^* values of all specimens were measured using the VITA Easyshade Advance 4.0. These values was used to determine the ∆E value and transparency. IBM SPSS Statistics ver. 24.0, a statistical significance level of 0.05 and one-way ANOVA were used for all data. Results: In all groups, the L^* and b^* values were the lowest in the specimens subjected to the 4th heat pressing and the corresponding a^* value was the highest. All specimens showed ∆E values of ≤3.3, indicating color changes that were not visible with the naked eye, and the color difference increased with the number of repeated heat pressing. The transparency of all specimens decreased as the number of repeated uses increased. Conclusion: According to the number of repeated heat pressing, the color difference of Rosetta SP (HASSBIO) was larger than that of IPS e.max Press (Ivoclar Vivadent), but it was clinically acceptable in all groups. Moreover, transparency decreased as the number of heat presses increased in all groups. According to the above findings, the lithium disilicate glass-ceramic has high color stability due to repeated heat pressing, implying that it can be used in clinical settings regularly.