• Korean Journal of Heritage: History & Science
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• v.44 no.4
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• pp.130-141
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• 2011

This paper examined the bleaching effect of the two types of gel made with neutralizing agent such as sodium meta silicate gel & triethylamine gel mixed with carbopol resin 940 & 934 which has thickness effect in broad pH region and mixed with 10% hydrogen peroxide. Sodium meta silicate gel(1.6g included) provided pH 10, the most suitable environment for bleaching. The result of comparison of the baseline colour changes(${\Delta}E*ab$) and colour changes according to time(${\Delta}E*ab$) is as following. Group1(carbopol 940, sodium meta silicate, Urea Hydrogen Peroxide) showed 112% efficiency at CS-2; 63.3% at CS-4; 87.4% at CS-6. Group2(carbopol 934, sodium meta silicate, Urea Hydrogen Peroxide) showed 77.3%, 67.3%, 109.6% at CS-8, CS-10, CS-12 respectively; CT-1, CT-3, CT-5 of Group3(carbopol 940, triethylamine, Urea Hydrogen Peroxide) showed 36.8%, 73.2%, 74%; In Group4(carbopol 934, triethylamine, Urea Hydrogen Peroxide), efficiency of CT-6, CT-8, and CT-10 was 81.7%, 95.4%, and 95.7%. The paper showed that various concentration of neutralizing agent such as sodium meta silicate and triethylamine have bleaching effect. Viscosity of the gel including sodium meta silicate was higher than the gel including triethylamine. High viscosity helps the bleaching gel sit on the smooth slope of the ceramics. As a result, sodium meta silicate is considered to provide thickening and bleaching effect required in producing 10% hydrogen peroxide gel.

• Journal of Elementary Mathematics Education in Korea
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• v.11 no.1
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• pp.43-59
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• 2007

The goal of this thesis was to examine the effects of applying meta-problems to elementary school mathematics class In their achievements, beliefs and attitudes. To achieve this goal the following research questions were asked. a. What effects does the class applied with meta-problem have on students' mathematical achievements? b. What effects does the class applied with meta-problem have on students' mathematical beliefs and attitudes? To answer questions, an experimental study was designed and conducted. The subjects were 6th-grade students at S Elementary School located in Dobong-Gu, Seoul where the researcher teaches. Among them, the class that the researcher teach was chosen as the experimental group. During the experimental study, a teaching-learning with meta-problems was applied to the experimental group and a teaching-learning with general problems was applied to the comparative group. To examine changes in the mathematical achievements of the experimental group and the comparative group, a post-test of mathematical achievements was conducted and the results were t-tested. As well, to find answers to the second research question, a pre-test and a post-test of mathematical beliefs and attitudes were conducted on the experimental group and the results were t-tested. The results of this study were as follows First, the experimental group which was taught applying meta-problems got higher mathematical achievement than the comparative group. Second, the class with meta-problems did not bring significant changes in students' mathematical beliefs and attitudes. Synthesizing the study results above, a teaching-learning with meta-problems is a teaching-learning method that can accommodate problem solving naturally in school mathematics and give a positive effect on students' mathematical achievements.

• Journal of Environmental Health Sciences
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• v.46 no.3
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• pp.245-255
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• 2020

Objective: The present study analyzed domestic and overseas academic journals to understand the research status and characteristics of radon concentration distribution in Korea in accordance with environmental conditions. Methods: As part of the meta-analysis, pooled average concentration was calculated using an inverse variance-weighted average of the arithmetic means and standard deviations among the investigated values. Using the obtained pooled average concentration, a Monte-Carlo simulation was performed to increase the reliability of the occurrence possibility of the calculated concentration distribution. A total of 38 research articles were selected, including 27 articles published in domestic academic journals and 11 articles published in foreign academic journals. Results: The comparison results showed differences in radon concentration distribution in accordance with regional and topographical characteristics. Conclusion: Currently, even though research into radon is steadily picking up the pace in Korea much remains to be done. Additional research is thus needed to establish a baseline for radon emissions in Korea.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.78.4-79
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• 2016

This study aims to overview research articles on extrasolar planets using Kepler mission data during the period of 2009-2015 in order to discover research trends in them. Kepler space observatory is a NASA space observatory for extrasolar planet expedition launched in March 2009, contributed to the discovery and tracking of extrasolar planets and its candidates. In order to achieve the goal of this study, we classified research subjects from studies on Kepler mission data year by year and found the most frequent research topics each year. We also conducted a comparative analysis on the research subjects based on time series and examined any changes with respect to the goal of Kepler mission. Statistical meta-analysis is employed as the analysis method for the key words presented in the research articles. This study is a part of on-going research to find the correlation between the physical parameters of the host star and extrasolar planets. The results of this study could offer new directions in researches utilizing Kepler mission data as those meta-analyses in social sciences often suggest new opportunities. We have high expectations that more extrasolar planet studies will follow as we make further progresses in various analyses.

• Journal of Preventive Medicine and Public Health
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• v.50 no.6
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• pp.347-360
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• 2017

Objectives: This meta-analysis aimed to evaluate congenital malformations in infants conceived by assisted reproductive techniques (ART), compared with infants conceived spontaneously. Methods: In this study, available resources searched to find relevant articles included PubMed, ScienceDirect, Scopus, Google Scholar, Cochrane, ProQuest, Iranmedex, Magiran, and Scientific Information Database. After extracting the necessary information from evaluated articles, meta-analysis on the articles' data was performed using Stata version 11.2. Results: In this study, from a total of 339 articles, extracted from the initial investigation, ultimately 30 articles were selected for meta-analysis that assessed the use of ART on the risk of congenital abnormalities and some birth complications on 5 470 181 infants (315 402 cases and 5 154 779 controls). The odds ratio (95% confidence interval [CI]) for low birth weight was 1.89 (95% CI, 1.36 to 2.62), preterm labor 1.79 (95% CI, 1.21 to 2.63), cardiac abnormalities 1.43 (95% CI, 1.27 to 1.62), central nervous system abnormalities 1.36 (95% CI, 1.10 to 1.70), urogenital system abnormalities 1.58 (95% CI, 1.28 to 1.94), musculoskeletal disorders 1.35 (95% CI, 1.12 to 1.64), and chromosomal abnormalities in infants conceived by ART was 1.14 (95% CI, 0.90 to 1.44), which were all statistically significant, except chromosomal abnormalities. Conclusions: The risk of congenital abnormalities and some birth complications were significantly higher in ART than normal conception, while chromosomal abnormalities were not; therefore, the application of ART should be selected individually for patients by detailed assessment to reduce such risks in the population.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.23
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• pp.10421-10425
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• 2015

Background: While the incidence of non-Hodgkins lymphoma (NHL) has been rising worldwide, the reasons remain undefined. Recent research has focused on effect of red andf processed meat intake as a risk factor, but with inconclusive results. We therefore conducted a meta-analysis of data published to date, to ascertain the overall association between intake and NHL. Materials and Methods: A published literature search was performed through Pubmed, Cochrane Library, Medline, and Science Citation Index Expanded databases for articles published in English. Pooled odds ratios (ORs) and 95% confidence intervals (95%CIs) were calculated using random or fixed effects models. Heterogeneity was assessed using Chi-square and I2 statistics. Dissemination bias was evaluated by funnel plot analysis.We performed a formal meta-analysis using summary measures from these studies. Results: In total, 11 published studies were included in the final analysis. The combined analysis revealed that there was significant association between the red meat and NHL risk (OR=1.10, 95%CI: 1.02 to 1.19, p=0.01). Additionally, there was showed significance association between processed red meat and NHL risk (OR=1.17, 95%CI: 1.06 to 1.29, p=0.001). In subgroup analysis, a statistical significant association was noted between diffuse large B-cell lymphoma (DLBCL) (OR=1.20, 95%CI: 1.04 to 2.37, P=0.01) and red meat intake. Conclusions: In this meta-Analysis, there was evidence for association between consumption of red meat, or processed meat and risk of NHL, particularly with the DLBCL subtype in the red meat case.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.7
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• pp.4283-4287
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• 2013

Background: In this meta-analysis we review evidence suggesting that exposure to cadmium is a cause of breast cancer. Materials and Methods: We conducted Medline/PubMed and Scopus searches using selected MeSH keywords to identify papers published from January 1, 1980 through January 1, 2013. Data were merged and summary mean differences were estimated using either a random-effects model or a fixed-effects model. Results: There were 13 studies including 978 exposed cases and 1,279 controls. There was no statistically significant difference in the frequencies of breast cancer between cadmium-exposed and control groups, and the summary estimate of mean difference was 0.71 (95%CI: 0.33-1.08). However, stratification showed that there were statistically significant differences in the frequencies of breast cancer between cadmium-exposed and control groups among Asian compared with Caucasian population, and the summary estimates of mean difference were 1.45 (95%CI: 0.62-2.28) vs. 0.25 (95%CI: -0.09-0.6), respectively. There was a difference in the frequencies of breast cancer between cadmium-exposed and control groups in peripheral venous blood sampling methods, and the summary estimate of mean difference was 1.41 (95%CI: 0.46-2.37). Conclusions: Data indicate that the frequencies of breast cancer might be an indicator of early genetic effects for cadmium-exposed populations. However, our meta-analysis was performed on population-based studies; meta-analysis based on individual data might provide more precise and reliable results. Therefore, it is necessary to construct an international database on genetic damage among populations exposed to cadmium that may contain all raw data of studies examining genetic toxicity.

• The Journal of Korean Academy of Prosthodontics
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• v.39 no.1
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• pp.49-57
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• 2001

The use of autopolymerizing-cured resin and light-cured resin for direct introral relining of complete and partial dentures has been popular. The purpose of this investigation was to determine the surface characteristics of autopolymerizing-cured reline resins(Tokuso rebase, Mild rebaron, Meta base) and light-cured reline resin(Mild rebaron LC). Acrylic resin slab specimens(1.0cm in diameter at the bottom, and 0.3cm high) were made against glass according to the instructions of the manufacturer following normal procedures for each of direct reline resins and examined the surface characteristics by use of surface profilometer and the other specimens which were made intraorally for each of direct reline resins were examined by use of scanning electron microscopy. The results were as follows : 1. Each surface roughness(Rz) of hard relin resins was $0.14{\pm}0.04{\mu}m$ in Tokuso rebase, $0.37{\pm}0.11{\mu}m$ in Mild Rebaron, $0.79{\pm}0.44{\mu}m$ in Mild Rebaron LC, $6.36{\pm}3.40{\mu}m$ in Meta base. There were significant differences between the surface roughness of Meta base and those of other reline resins(p<0.05) 2. The generation of porosity was the most in Tokuso Rebase and followed by Meta base, Mild Rebaron and Mild Rebaron LC in the order respectively. 3. Light-cured reline resin(Mild rebaron LC) was denser in surface than any other autopolymerizing-cured reline resins. Tokuso rebase and Mild rebaron was denser than Meta base. Conclusively, light-cured reline resin(Mild rebaron LC) had less porosity and better surface density than any other autopolymerizing-cured reline resins.

• Journal of Digital Convergence
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• v.18 no.7
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• pp.331-337
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• 2020

The purpose of this study was to meta-synthesize the results of qualitative research that explored the experiences of nursing care in a domestic nurse to understand the phenomenon. The research method was a qualitative meta-synthesis study, which was analyzed using Thomas and Harden's methods. This was analyzed by searching for quality assessments for individual studies, extracting data for analysis, and meta-synthesizing the results. As a result of the study, it appeared as five synthetic themes. 1) Disaster nursing that begins with anxiety and fear, 2) Disaster nursing process: An atmosphere that feels even loneliness and burden in isolation and disconnection, 3) Disaster nursing process: Being in a poor and diverse environment, 4) Disaster nursing process: Although exhausted Endure and overcome. 5) After disaster care: A leap forward for development beyond mission and self-esteem. Conclusion, this study is expected to be a useful basic data for the development and application of nurse's disaster nursing programs and educational programs in the future.

• Journal of Korean Academy of Nursing
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• v.52 no.5
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• pp.479-498
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• 2022

Purpose: This study aimed to examine effect sizes of leadership styles of nursing managers on turnover intention of hospital nurses. Methods: A systematic review and meta-analysis were conducted in accordance with the PRISMA and MOOSE guidelines. Participants were nurses working in hospitals. The intervention involved nursing managers' leadership styles; the outcome assessed was nurses' turnover intention. This was an observational study design. Eleven databases were searched to obtain articles published in Korean or English. Of the 14,428 articles reviewed, 21 were included in systematic review and meta-analysis. Comprehensive Meta-Analysis and R software programs were used. Results: The total effect size r (ESr) was - 0.25 (95% confidence interval: - 0.29 to - 0.20). Effect sizes of each leadership style on turnover intention were as follows: ethical leadership (ESr = - 0.34), transformational leadership (ESr = - 0.28), authentic leadership (ESr = - 0.23), transactional leadership (ESr = - 0.21), and passive avoidant leadership (ESr = 0.13). Ethical leadership was the most effective style in decreasing turnover intention of hospital nurses. Conclusion: Positive leadership styles of nurse managers effectively decrease turnover intention of hospital nurses, and negative leadership styles of nurse managers effectively increase turnover intention of hospital nurses. The ethical leadership style is the most effective in decreasing turnover intention of hospital nurses; however, it requires careful interpretation as its effects are reported by only two studies. This study contributes to addressing the high turnover rate of hospital nurses and developing positive leadership styles of nurse managers in hospital settings.