• Journal of the Korean Society of School Health
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• v.13 no.2
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• pp.261-270
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• 2000

Background: Adolescence is the transitional period between childhood and adulthood. We have to pay attention to their psycho-social problems as well as their physical symptoms. In this context, we need to investigate the adolescent depression tendency and its related factors. Method : From May to June in 1008, we chose one elementary school, one middle school and one high school in Seoul and surveyed for all students who were above the 4th grade of elementary school and their parents. We analyzed the data for 3,685 students. Result: From the 6th grade of elementary school to the 1st grade of high school, the girls' DSRS(Depression self-rating scale) score was significantly higher than the boys'. The DSRS score was increased from the 2nd grade of high school for boys and from the 1st grade of high school for girls. The Pearson correlation coefficient between age and DSRS score was 0.16(p<0.01) and that between APGAR and DSRS score was -0.45(p<0.01). The median number of psychosomatic symptoms of the past month was 6, and when students complained for more psychosomatic symptoms, the DSRS scores were higher. Those who drank or smoked ranked significantly higher in DSRS score; and, those who exercised regularly, had leisure activity, and had a faithful person for counselling ranked significantly lower in DSRS score. Conclusion : Adolescents who complained of many psychosomatic symptoms needed to be screened for depression. A primary physician have to intervene about health related behavior such as family function, smoking, exercise and relieving stress.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.122-122
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• 2017

Recently, environmental problems have become an area of growing interests. In-situ monitoring of water quality is fundamental to most environmental applications. The accurate measurement of nitrate concentrations is fundamental to understanding biogeochemistry in aquatic ecosystems. Several studies have reported that one of the most feasible methods to measure nitrate concentration is the use of Ion Selective-electrodes (ISEs). The ISE application to water monitoring has several advantages, such as direct measurement methodology, high sensitivity, wide measurement range, low cost, and portability. However, the ISE methods may yield inconsistent results where there was a difference in temperature between the calibration and measurement solutions, which is associated with the temperature dependence of ionic activity coefficients in solution. In this study, to investigate the potential of using the combination of a temperature sensor and nitrate ISEs for minimizing the effect of temperature on real-time nitrate sensing in natural water, a prototype of on-site water monitoring system was built, mainly consisting of a sensor chamber, an array of 3 ISEs, an waterproof temperature sensor, an automatic sampling system, and an arduino MCU board. The analog signals of ISEs were obtained using the second-order Sallen-key filter for performing voltage following, differential amplification, and low pass filtering. The performance test of the developed water nitrate sensing system was conducted in a monitoring station of drinking water located in Jeongseon, Kangwon. A temperature compensation method based on two-point normalization was proposed, which incorporated the determination of temperature coefficient values using regression equations relating solution temperature and electrode signal determined in our previous studies.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.4
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• pp.594-603
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• 1994

This study investigate the balance and biochemical status of riboflavin in Korean men. During the experimental period, four riboflavin diets with different levels of riboflavin(0.4, 0.6,0.8 and 1.0mg/1000kcal) were followed by eight healthy college men. the riboflavin status was assayed by erythrocyte glutathine reudcctase activity coefficient (EGRAC0 and urinary excretion of riboflavin. Riboflavin intake of the subjects who consumed a det was 0.46mg/1000kcal. the riboflavin intakes of the subjects who consumed the experimental diet with 0.4, 0.6, 0.8 and 1,0mg/1000kcal of riboflavin were 0.41, 0.60, 0.81 , 0.97mg, respectively. Fecal riboflavin loss, absorbed riboflavin , urinary riboflavin loss and retained riboflavin increased in the subjects consumed 0.4, 0.6, 0.8 and 1.0mg/1000kcal of riboflavin. The average EGRAC values for the subjects consumed 0.4, 0.6, 0.8 and 1.0mg/1000kcal of riboflavin were 1.303$\pm$0.029, 1.271$\pm$0.022, 1.239$\pm$0.013, 1.202$\pm$0.030, respectively and urinary riboflavin values ($\mu\textrm{g}$/g creatinine) were 86.89$\pm$ 20.07, 123.88$\pm$ 15.88, 240.70$\pm$57.14 and 393.36$\pm$76.94, respectively. Results indicate that 0.6mg/1000kcal is the level of riboflavin intake needed to maintain urinary riboflavin within the normal range. And above1.0mg/1000kcal of riboflavin is need to maintain urinary riboflavin with in the normal range. And above 1.0mg/1000 of riboflavin is needed to maintain the EGRAC within the normal range. The riboflavin intake correlated positively with urinary riboflavin value, but correlated negatively with the EGRAC value. The EGRAC value correlated negatively to protein intake as well as animal protein intake. The linear equation of between riboflavin intake and EGRAc was EGRA=-0.1667 $\times$riboflavin intake +1.3710. The riboflavin intake to maintain EGRAc below 1.20 was calculated 1.02mg/1000kcal by the above equation.

• Journal of The Korean Association For Science Education
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• v.17 no.1
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• pp.1-10
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• 1997

The purpose of this study was to analyze the structural model of causal effects of students' variables on science process skills. Student characteristics investigated in the study included attitude related to the science, logical thinking ability, scientific experiences, cognitive style. Covariance structural modeling procedures were used to test causal inferences about hypothesized relationships. The sample consisted of 319 6th grade students and 321 8th grade students in Seoul City, Korea. Five instruments were used in the study, TSPS(test of science process skills), GALT(group assessment of logical thinking), CEFT(children embedded figures test), questionnaire of attitude related to the science, questionnaire of scientific experience. For statistical analysis, the study adopted the structural equation modeling with LlSREL, a computer statistical program developed by J reskog and S rbom. Major findings of the study are as follows:1) Logical thinking ability has a most strong direct effect on science process skills. 2) The structural coefficient of scientific experience influence on attitude related to the science has the greatest direct one than the others in the covariance structural model. According to the results of this study, it is very importance that various scientific experiences, particularly hands-on activity, should be offer to students to improve science process skills. Also, understanding the relationships of student variable to science process skills will be helpful to decision making on the part of curriculum developers, science teachers and researchers.

• Journal of The Korean Association For Science Education
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• v.31 no.5
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• pp.709-719
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• 2011

The purpose of this study was to identify the differences in classification skills shown in classification activities between the gifted and regular students in elementary schools. The subjects for the research consisted of six gifted students in an institute for the gifted for science annexed to P school district in Gangwon-do and 6 students at B and M general elementary schools. Results were as follows: The time taken for classification activities of the gifted was shorter than regular regardless of subjects for classifying. The number of standards for classifying for the gifted was more than regular students. Coefficient for measuring classification skills of the gifted was higher than regulars regardless of age. Consequently, there was a difference in the time taken for classifying and generating the number of standards and in a numerical index of classification activities performed at science classes between the science gifted and the regular students.

• KSBB Journal
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• v.22 no.1
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• pp.62-65
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• 2007

New strain development strategy using kinetic models and metabolic control analysis was investigated. In this study, previously reported mathematical models describing the enzyme kinetics of intracellular threonine synthesis were modified for mutant threonine producer Escherichia coli TF5015. Using the modified models, metabolic control analysis was carried out to identify the rate limiting step by evaluating the flux control coefficient on the overall threonine synthesis flux exerted by individual enzymatic reactions. The result suggested the production of threonine could be enhanced most efficiently by increasing aspartate semialdehyde dehydrogenase (asd) activity of this strain. Amplification of asd gene in recombinant strain TF5015 (pCL-$P_{aroF}$-asd) increased the threonine production up to 23%, which is much higher than 14% obtained by amplifying aspartate kinse (thrA), other gene in threonine biosynthesis pathway.

• Progress in Medical Physics
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• v.11 no.2
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• pp.131-139
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• 2000

We designed high dose rate Ir-192 source which was prepared for substitute the Co-60 source in Ralstron unit (Simatsu, Japan) which is supplied for cervical cancer treatment. The source dimension is 1.5 mm in a diameter and 1.5mm thickness of cylinder and encapsulated with 3 mm diameter of stainless steel(SUS316L) to substituted for the Co-60 source size. The Ir-192 source was prepared the dose model for tissue dose computation through the experimental determination of apparent activity and applied the empirical tissue correction factors extended to 20cm distance. The tissue dose model was applied the 4.69 R/cm-mCi-hr gamma constant and the ratio of energy absorption coefficient of water to that of air showed 1.112 include filteration of the self-absorptions. In this experiments, we prepared the dose computation software to clinical usefulness.

• Korean Journal of Animal Reproduction
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• v.16 no.4
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• pp.353-361
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• 1993

This study was taken to examine external changes, behavioral changes, and endocrine changes such as estradiol-17$\beta$, progesterone, T4 and T3 of female Oreochromis niloticus living in 0$\textperthousand$, 10$\textperthousand$, 20$\textperthousand$, and 30$\textperthousand$ salt concentrations, respectively. The results obtained in these experiments were summarized as follows. In seawater obtained in these experiments were summarized as follows. In seawater challenge test, any fish didn't die in each group such as 10$\textperthousand$, 20$\textperthousand$ and 30$\textperthousand$. When fish were adapted from 0$\textperthousand$ to 10$\textperthousand$, 20$\textperthousand$ and 30$\textperthousand$, external body color of fish changed from dark-striped to light-grey color. At the same time, thyroxine and triiodothyronine concentrations significantly(P<0.05) increased, and then were at the highest level in 30 salinity. When fish were adapted from 0$\textperthousand$ to 10$\textperthousand$, feed intake of fish started from the fourth day. From 0$\textperthousand$ to 10$\textperthousand$, 20$\textperthousand$ and 30$\textperthousand$, estradiol-17$\beta$ levels were increased gradually. When fish was adapted from 0$\textperthousand$ to 10$\textperthousand$, 20$\textperthousand$ and 30$\textperthousand$, the levels of each progesterone didn't show significant change, and especially showed the lowest peak in 20$\textperthousand$. The greatest thyroxine activity(T4) was observed in 30$\textperthousand$. The levels of and triiodothyronine(T3) significantly changed in all salinities, and its level was at the highest peak in 30$\textperthousand$ salinity. Correlation coefficients between serum progesterone and triiodothyronine in 10$\textperthousand$ and 30$\textperthousand$ were ＋0.677 and ＋0.843, respectively. Correlation coefficient of serum thyroxine(T4) and triiodothyronine(T3) individuals in 10$\textperthousand$ was ＋0.768, and ＋0.843, respectively.

• Fire Science and Engineering
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• v.15 no.3
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• pp.14-20
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• 2001

The flash points are one of the most important fundamental properties used to determine the potential for fire and explosion hazards of flammable substances. A classification of the flash points is important for the safe handling of flammable liquids which constitute the solvent mixtures. Basic to all flash points behavior are vapor pressure and explosive limits(lower explosive limit and upper explosive limit). The flash points of flammable solvent mixtures can be calculated with the appropriate use of the fundamental laws of Raoult, Dalton, Le Chatelier and activity coefficient models. In this study, the reference values of lower flash points were compared with the calculated values by using Raoult's law and MRSM(modified response surface methodology) model. The lower flash points were in agreement with the predicted by Raoult's law and MRSM model. By means of this methodology, it is possible to evaluate reliability of experimental data of the flash points of the flammable mixtures.

• Korean Journal of Pharmacognosy
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• v.45 no.4
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• pp.300-314
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• 2014

An ultra-performance liquid chromatography-electrospray ionization-mass spectrometer (UPLC-ESI-MS) method was established for the simultaneous quantification of eighteen marker compounds in traditional Korean formula, Cheonwangbosimdan (CWBSD). In addition, we evaluated the antioxidant effects of CWBSD. Eighteen marker components were separated on a UPLC BEH $C_{18}$ analytical column ($2.1{\times}100mm$, $1.7{\mu}m$) and kept at $45^{\circ}C$ by gradient elution with 0.1% (v/v) formic acid in water and acetonitrile as mobile phase. The flow rate was 0.3 mL/min and the injection volume was $2.0{\mu}L$. The antioxidant activities of CWBSD were assessed by measuring free radical scavenging activities on 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and 1-1-diphenyl-2-picrylhydrazyl (DPPH). The calibration curves of all analytes showed good linearity (correlation coefficient ${\geq}0.9937$) within the test ranges. The limits of detection and quantification for the 18 marker compounds were 0.01-4.71 ng/mL and 0.03-14.13 ng/mL, respectively. The contents of the 18 compounds in CWBSD extract ranged from none to $1701.00{\mu}g/g$. The CWBSD showed the radical scavenging activity in a dose-dependent manner. The concentration required for 50% reduction ($RC_{50}$) against ABTS and DPPH radicals were $149.42{\mu}g/mL$ and $339.24{\mu}g/mL$.