• Korean Journal of Child Studies
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• v.35 no.3
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• pp.157-176
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• 2014

A total of 378 $4^{th}$ and $5^{th}$ grade elementary school students (194 boys and 184 girls) participated in a study investigating the direct and indirect effects (through self-esteem and/or achievement motivation) of children's perceptions of parental expectations on school happiness. First, parental expectations did not have a direct effect on children's levels of school happiness. Second, parental expectations did not have an indirect effect on children's school happiness through self-esteem. Children who perceived higher levels of parental expectations showed higher levels of self-esteem, but the path from children's self-esteem to school happiness was not significant. Third, parental expectations had an indirect effect on children's levels of school happiness through achievement motivation. Children who perceived higher levels of parental expectations showed higher levels of achievement motivation, and children with higher levels of achievement motivation reported higher levels of school happiness. Finally, parental expectations indirectly influenced children's school happiness through self-esteem and achievement motivation. These findings suggest that both environmental and individual factors need to be considered together to more comprehensively explain children's levels of school happiness.

• Korean Journal of Child Studies
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• v.34 no.4
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• pp.65-81
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• 2013

The purpose of this study was to examine the relationships between career maturity, anxiety and school related adjustments levels of adolescents. A sample of 319 1th grade high school students in Seoul Metropolitan area participated in this study. The subjects completed questionnaires on the levels of school related adjustments, anxiety and career maturity. Data were analyzed by means of Pearson's correlation coefficients, as well as multiple and hierarchical regressions. Career maturity, as well as anxiety was founded to be a predictor to the school related adjustments levels of adolescents; significant interactional effects were found between career maturity and anxiety in terms of school related adjustments. These results indicate the need for possible interventions in relation to adolescents' anxiety levels and to improve the school related adjustments levels of adolescents.

• Journal of the Korean Society of School Health
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• v.24 no.2
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• pp.190-198
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• 2011

Purpose: The purpose of this study was to compare stress levels of middle school students by grade. Methods: This was a descriptive comparative survey using as convenience sample of 701 1st, 2nd and 3rd-grade students. The stress levels was measured by stress scale that consisted of 65 items regarding personal characters family, school, and peer factors. The data were analyzed by ${\chi}^2$-test, t-test, ANOVA, and multiple regression using the SPSS/WIN 12.0 statistical program. Results: 1st graders and female students showed higher stress levels than 2nd, 3rd graders and male students, respectively. Conclusion: Grade, gender, life satisfaction, and regional levels were all significant factors associated with high stress levels among middle school students. Development of stress management program for this specific population, especially targeting students who are 1st Grader and living in rural areas, is needed.

• Journal of Preventive Medicine and Public Health
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• v.45 no.6
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• pp.387-393
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• 2012

Objectives: Even though several epidemiological studies have observed positive associations between blood lead levels and homocysteine, no study has examined whether this association differs by the levels of micronutrients, such as folate, vitamin B6, and vitamin B12, which are involved in the metabolism of homocysteine. In this study, we examined the interactions between micronutrients and blood lead on homocysteine levels. Methods: This study was performed with 4089 adults aged ${\geq}20$ years old in the US general population using the National Health and Nutrition Examination Survey 2003-2004. Results: There were significant or marginally significant interactions between micronutrients and blood lead levels on mean homocysteine levels. Positive associations between blood lead and homocysteine were clearly observed among subjects with low levels of folate or low vitamin B6 (p-trend <0.01, respectively). However, in the case of vitamin B12, there was a stronger positive association between blood lead and homocysteine among subjects with high levels of vitamin B12, compared to those with low levels of vitamin B12. In fact, the levels of homocysteine were already high among subjects low in vitamin B12, irrespective of blood lead levels. When we used hyperhomocysteinemia (homocysteine>15 ${\mu}mol/L$) as the outcome, there were similar patterns of interaction, though p-values for each interaction failed to reach statistical significance. Conclusions: In the current study, the association between blood lead and homocysteine differed based on the levels of folate, vitamin B6, or vitamin B12 present in the blood. It may be important to keep sufficient levels of these micronutrients to prevent the possible harmful effects of lead exposure on homocysteine levels.

• Korean Journal of Community Nutrition
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• v.10 no.5
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• pp.668-676
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• 2005

The purpose of this study was to determine the relationship between the students' levels of involvement in school lunch service and their satisfaction levels with the service. A survey was conducted with $5^{th}\;and\;6^{th}$ grade elementary students eating school lunches. Out of 1,680 questionnaires distributed to the students from 14 schools, 1,254 complete questionnaires $(74.6\%)$ were analyzed. The questionnaire included two 5-point multi-item scales for measuring levels of involvement in and satisfaction with school lunch service, respectively. A factor analysis grouped 20 items measuring school lunch satisfaction into three factors: 'food satisfaction', 'nutrition & sanitation satisfaction', and 'service & environment satisfaction'. As a result of multiple regression analyses controlling the influence of such variables as students' grades, gender, school location, years and places of eating school lunches, students' levels of involvement in school lunch service was proven to be positively associated with levels of school lunch satisfaction overall, as well as satisfaction levels in regard to 'food', 'nutrition & sanitation', and 'service & environment', respectively. It was suggested that efforts such as nutrition education to increase students' levels of involvement in school lunches could be a useful strategy to improve students' satisfaction with school lunch service.

• School Mathematics
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• v.4 no.1
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• pp.15-27
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• 2002

The purpose of this thesis is, through analysing the characteristics of the definitions in Korean school mathematics textbooks, to explore the levels of them. Definitions use din academic mathematics are rigorous. But they should be transformed into various types, which are presented in school mathematics textbooks, with didactical purposes. In this thesis we investigated such types of transformation. With the result of this investigation we tried to identify the levels of the definitions in school mathematics textbooks. We tried to construct, with consideration about methods of definition, frame for analysing the types of the definitions in school mathematics. Methods of definition are classified as connotative method, denotative method, and synonymous method. Especially we identified that connotative method contains logical definition, genetic definition, relational definition, operational definition, and axiomatic definition. With these analyses we made a frame for investigating the characteristics of the definitions in school mathematics textbooks. With this frame we identified concrete types of transformations of methods of definition. We tried to analyse this result with van Hieles' theory about let·els of geometry learning and the mathematical language levels described by Freudenthal, and identify the levels of definitions in school mathematics. We showed the levels of definitions in the geometry area of the Korean school mathematics.

• Human Ecology Research
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• v.56 no.2
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• pp.157-165
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• 2018

Using data from the Panel Study on Korean Children, this study investigated whether children with high levels of problem behaviors adjusted more poorly on the $1^{st}-grade$ than children with low levels of problem behaviors, and whether there was evidence of intra-individual stability in behavior problems over time. Data were analyzed by use of the Latent Growth Model and group differences analyses. Three findings were noteworthy. First, there was evidence of intra-individual and inter-individual variability in behavior problems between poor- and non-poor household children. Second, children with higher initial levels of internalizing and externalizing behaviors at 4 years had lower school readiness scores at 6 years. Finally, children with lower levels of school readiness at 6 years had lower school adjustment scores in $1^{st}$ grade. The results discuss implications for future research and policies for preschool children. With mediating effect of school readiness, developmental trajectories of child's problem behavior have been found to be predictors of delayed achievements in school. The results show that intervention programs are necessary for children with high levels of problem behavior. This study also showed that children who experienced poverty at home could have more difficulties in school readiness and school adjustment.

• The Korean journal of internal medicine
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• v.39 no.2
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• pp.318-326
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• 2024

Background/Aims: Epidermal growth factor receptor (EGFR) mutation is important in determining the treatment strategy for advanced lung cancer patients with malignant pleural effusion (MPE). Contrary to serum carcinoembryonic antigen (S-CEA) levels, the associations between pleural fluid CEA (PF-CEA) levels and EGFR mutation status as well as between PF-CEA levels and treatment efficacy have rarely been investigated in lung adenocarcinoma patients with MPE. Methods: This retrospective study enrolled lung adenocarcinoma patients with MPE and available PF-CEA levels and EGFR mutation results. The patients were categorized based on PF-CEA levels: < 10 ng/mL, 10-100 ng/mL, 100-500 ng/mL, and ≥ 500 ng/mL. The association between PF-CEA levels and EGFR mutation status as well as their therapeutic impact on overall survival was compared among the four groups. Results: This study included 188 patients. PF-CEA level was found to be an independent predictor of EGFR mutation but not S-CEA level. The EGFR mutation rates were higher as the PF-CEA levels increased, regardless of cytology results or sample types. Among EGFR-mutant lung adenocarcinoma patients receiving EGFR-tyrosine kinase inhibitor (TKI) treatment, those with high PF-CEA levels had significantly better survival outcomes than those with low PF-CEA levels. Conclusion: High PF-CEA levels were associated with high EGFR mutation rate and may lead to a favorable clinical outcome of EGFR-TKI treatment in EGFR-mutant lung adenocarcinoma patients with MPE. These findings highlight the importance of actively investigating EGFR mutation detection in patients with suspected MPE and elevated PF-CEA levels despite negative cytology results.

• Clinical and Experimental Pediatrics
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• v.58 no.1
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• pp.15-19
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• 2015

Purpose: Soluble transferrin receptor (sTfR) is a truncated extracellular form of the membrane transferrin receptor produced by proteolysis. Concentrations of serum sTfR are related to iron status and erythropoiesis in the body. We investigated whether serum sTfR levels can aid in diagnosis and treatment of iron deficiency anemia (IDA) in children. Methods: Ninety-eight patients with IDA were enrolled and were classified according to age at diagnosis. Group 1 comprised 78 children, aged 6-59 months, and group 2 comprised 20 adolescents, aged 12-16 years. Results: In group 1, patients' serum sTfR levels correlated negatively with mean corpuscular volume; hemoglobin (Hb), ferritin, and serum iron levels; and transferrin saturation and positively with total iron binding capacity (TIBC) and red cell distribution width. In group 2, patients' serum sTfR levels did not correlate with ferritin levels and TIBC, but had a significant relationship with other iron indices. Hb and serum sTfR levels had a significant inverse relationship in both groups; however, in group 1, there was no correlation between Hb and serum ferritin levels. In 30 patients of group 1, serum sTfR levels were significantly decreased with an increase in Hb levels after iron supplementation for 1 month. Conclusion: Serum sTfR levels significantly correlated with other diagnostic iron parameters of IDA and inversely correlated with an increase in Hb levels following iron supplementation. Therefore, serum sTfR levels can be a useful marker for the diagnosis and treatment of IDA in children.

• Molecules and Cells
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• v.25 no.1
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• pp.105-111
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• 2008

Radiotherapy is an important treatment for many malignant tumors, but there are recent reports that radiation may increase the malignancy of cancer cells by stimulating expression of type IV collagenases. In this study, we examined changes in matrix metalloproteinase (MMP) inhibitors, such as the tissue inhibitors of metalloproteinase (TIMP)-1, TIMP-2 and RECK, in response to irradiation in Panc-1 pancreatic cancer cells. Irradiation increased RECK protein levels but not mRNA levels, whereas no significant changes were found in TIMP-1 and TIMP-2. The enhanced RECK protein levels were associated with an increase in MMP inhibitory activity. However, irradiation slightly but reproducibly increased the invasiveness of the Panc-1 cells. Like irradiation, treatment of Panc-1 cells with transforming growth factor $(TGF)-{\beta}1$ led to a 2-fold increase in RECK protein levels. Transient transfection with Smad3 also increased RECK protein levels, but transfection with Smad7 markedly reduced them. Stable expression of Smad7 and treatment with SB431542, an inhibitor of $TGF-{\beta}$ receptor I kinase, abolished $TGF-{\beta}1$- and radiation-mediated effects on RECK. Furthermore, irradiation increased levels of phosphorylated Smad3. We conclude that radiation post-transciptionally enhances RECK protein levels in Panc-1 cells, at least in part, via $TGF-{\beta}$ signaling, and that irradiation increases Panc-1 invasiveness via a mechanism that may not be linked to MMP-2 activity.