• Restorative Dentistry and Endodontics
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• v.48 no.1
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• pp.3.1-3.14
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• 2023

Objectives: This study evaluated the effect of different nanoparticulated zinc oxide (nano-ZnO) and conventional-ZnO ratios on the physicochemical properties of calcium aluminate cement (CAC). Materials and Methods: The conventional-ZnO and nano-ZnO were added to the cement powder in the following proportions: G1 (20% conventional-ZnO), G2 (15% conventional-ZnO + 5% nano-ZnO), G3 (12% conventional-ZnO + 3% nano-ZnO) and G4 (10% conventional-ZnO + 5% nano-ZnO). The radiopacity (R_ad), setting time (S_et), dimensional change (D_c), solubility (S_ol), compressive strength (C_st), and pH were evaluated. The nano-ZnO and CAC containing conventional-ZnO were also assessed using scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. Radiopacity data were analyzed by the 1-way analysis of variance (ANOVA) and Bonferroni tests (p < 0.05). The data of the other properties were analyzed by the ANOVA, Tukey, and Fisher tests (p < 0.05). Results: The nano-ZnO and CAC containing conventional-ZnO powders presented particles with few impurities and nanometric and micrometric sizes, respectively. G1 had the highest Rad mean value (p < 0.05). When compared to G1, groups containing nano-ZnO had a significant reduction in the S_et (p < 0.05) and lower values of D_c at 24 hours (p < 0.05). The C_st was higher for G4, with a significant difference for the other groups (p < 0.05). The S_ol did not present significant differences among groups (p > 0.05). Conclusions: The addition of nano-ZnO to CAC improved its dimensional change, setting time, and compressive strength, which may be promising for the clinical performance of this cement.

• Journal of Practical Agriculture & Fisheries Research
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• v.3 no.1
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• pp.85-93
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• 2001

The inter-relationship and combining abilities of characters for leaf length, leaf width, branch number, leaf number, leaf area, fresh weight and dry weight were studied in the F₁ combination of 15 crosses from the partial six-parent diallel cross in Petunia hybrida. The leaf area, fresh weight and dry weight showed high positive correlation together with the other growth characters such as leaf length, leaf width, branch number, leaf number. The mean squares of general combining ability(GCA) and specific combining ability(SCA) were highly significant for all the growth characters. The estimates of variance components of SCA were greater than those of GCA for all the characters, showing preponderance of non-additive gene actions for these characters. GCA effect was high in the lines of D and G for leaf length and fresh weight, and in the lines of C and D for branch number, leaf number, leaf area and fresh weight. The crosses of D×E, D×G, and E×G exhibited high SCA effect for all the growth characters such as leaf length, leaf width, branch number, leaf number, leaf area, fresh weight, and dry weight. The broad sense heritability was generally high compared to narrow sense one in the 7 characters. The highest heritability of the broad and narrow sense was shown in the leaf width and dry weight.

• The Korean Journal of Pain
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• v.36 no.1
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• pp.128-136
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• 2023

Background: The authors aimed to compare the effects of a one-time ultrasound (US)-guided subacromial corticosteroid injection and three-time ozone (O₂-O₃) injection in patients with chronic supraspinatus tendinopathy. Methods: Participants were randomly assigned to the corticosteroid group (n = 22) or ozone group (n = 22). Injections in both groups were administered into subacromial bursa with an US-guided in-plane posterolateral approach. Primary outcome measure was the change in the Western Ontario Rotator Cuff Index (WORC) score between baseline and 12-weeks post-injection. Secondary outcome measures included visual analog scale and Shoulder Pain and Disability Index scores. Assessments were recorded at baseline, and 4-weeks and 12-weeks post-injection. Results: Forty participants completed this study. Based on repeated measurement analysis of variance, a significant effect of time was found for all outcome measures in both groups. Both the groups showed clinically significant improvements in shoulder pain, quality of life, and function. Baseline, 4-week post-injection, and 12-week post-injection WORC scores (mean ± standard deviation) were 57.91 ± 18.97, 39.10 ± 20.50 and 37.22 ± 27.31 in the corticosteroid group, respectively and 69.03 ± 15.89, 39.11 ± 24.36, and 32.26 ± 24.58 in the ozone group, respectively. However, no significant group × time interaction was identified regarding all outcome measures. Conclusions: Three-time ozone injection was not superior to a one-time corticosteroid injection in patients with chronic supraspinatus tendinopathy. It might be as effective as corticosteroid injection at 4-weeks and 12-weeks post-injection in terms of relieving pain and improving quality of life and function.

• 한국노년학
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• v.25 no.2
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• pp.53-71
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• 2005

Objectives: The purposes of this study were to investigate CHPs' knowledge, attitude, and practice regarding UI, and to identify predictors of their UI related practice. Methods: A descriptive-correlational study using self-administered questionnaire was conducted. A total of 330 members of the local Korean Association of CHPs were included in this study. A mailed survey was conducted to collect data. Findings: Of CHPs surveyed, 170(51.5%) returned completed questionnaire. Educational preparation of CHPs regarding UI was limited. The mean correct score of knowledge scale was 68.96%. Overall, CHPs exhibited positive attitudes toward UI. CHPs in this study were not actively participate UI related practice. Contrary to expectation, knowledge was not significantly related to CHPs' practice regarding UI. In the final analysis, CHPs' practice regarding UI was predicted by attitude toward the care of UI clients and educational needs for UI and these two variables explained 9% of variance of UI related practice. Conclusion: The results of this study suggest the importance of attitude and educational needs in shaping UI related practice among CHPs. To facilitate UI related practice among CHPs, efforts for attitudinal change related to UI among CHPs are needed. Moreover, continuing educational program for UI management should be developed, applied and evaluated.

• 한국노년학
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• v.30 no.4
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• pp.1129-1143
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• 2010

The purposes of this study were to investigate the major determinants influencing on health promoting behaviors(HPB) of the elderly living in Seoul. The conceptual framework of the study was Pender's health promoting model and the ecological perspectives. The study was conducted with 495 elderly persons whom 60 years old. For the analysis of data, descriptive statistics and hierarchical regression were used for the statistical analysis with SPSS program. The results were as following: 1) The mean score of the HPB was 3.11(SD=0.41). 2) Hierarchical regression analysis found that ModelIV accounted for 55.7% of the variance in HPB. 3) The Major determinants on HPB among the elderly persons were prior related perceived benefits of action, social support, perceived self-efficacy, community environment, perceived health status, education, and age. In conclusions, first, we should develop to various levels of educational and supportive programs for the HPB among the elderly persons. Second, we should examine more with environment, the accessibility to senior welfare agencies. Third, we should be organized the self-help groups for the elderly persons to improve health promoting behaviors. Fourth, the government should established more secure environment for the HPB, and find better solutions that are provided by various social welfare agencies connected with the coordination of the services in the local communities. Finally, we should develop professional education training programs of the HPB for the practitioners in the field of Gerontological Social Work.

• The Korean Journal of Applied Statistics
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• v.36 no.5
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• pp.381-397
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• 2023

The most representative design used in clinical trials is randomization, which is used to accurately estimate the treatment effect. However, comparison between the treatment group and the control group in an observational study without randomization is biased due to various unadjusted differences, such as characteristics between patients. Propensity score weighting is a widely used method to address these problems and to minimize bias by adjusting those confounding and assess treatment effects. Inverse probability weighting, the most popular method, assigns weights that are proportional to the inverse of the conditional probability of receiving a specific treatment assignment, given observed covariates. However, this method is often suffered by extreme propensity scores, resulting in biased estimates and excessive variance. Several alternative methods including trimming, overlap weights, and matching weights have been proposed to mitigate these issues. In this paper, we conduct a simulation study to compare performance of various propensity score weighting methods under diverse situation, such as limited overlap, misspecified propensity score, and treatment contrary to prediction. From the simulation results overlap weights and matching weights consistently outperform inverse probability weighting and trimming in terms of bias, root mean squared error and coverage probability.

• Korea Trade Review
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• v.48 no.1
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• pp.127-163
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• 2023

The objective of this study is to investigate the volatility spillover effects among BDI, CCFI and SCFI. This paper will divide the empirical analysis section into two periods to analyze and compare the differences in volatility spillover effect between shipping freight indices before and after the outbreak of COVID-19 separately. First, in order to compare the mean spillover impact and index lead-lag correlations in BDI and CCFI indices, along with BDI and SCFI indices before and after COVID-19, the co-integration analysis and the test of Granger causality built on the VAR model were utilized. Second, the impulse response and variance decomposition are employed in this work to investigate how the shipping freight index responds to shocks experienced by itself and other freight indices in a short period. Before the COVID-19 epidemic, the results demonstrated that the BDI freight index is the Granger cause of the variable CCFI freight index. But the BDI and CCFI freight indices have no apparent lead-lag relationships after COVID-19, and this empirical result echoes the cointegration test result. After the COVID-19 epidemic, the SCFI index leads the BDI index. This study employs the VAR-BEKK-GARCH joint model to explore the volatility spillover results between dry bulk and container transport markets before and after COVID-19. The empirical results demonstrate that after COVID-19, fluctuations in the BDI index still affect the CCFI index in the maritime market. However, there is no proof of a volatility spillover relationship between the BDI and SCFI after the COVID-19 epidemic. This study will provide an insight into the volatility relationship among BDI, CCFI and SCFI before and after the the COVID-19 epidemic occurred.

• Journal of the Korea Society for Simulation
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• v.32 no.4
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• pp.69-76
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• 2023

To improve the financial stability of the National Pension, an appropriate target rate of return should be established based on pension liabilities, and asset allocation policies should be formulated accordingly. The purpose of this study is to calculate the target rate of return considering the contributions of subscribers and the pension benefits, and based on this, derive an asset allocation. To do this, we utilized the internal rate of return methodology to calculate the target rate of return for each cohort. And then, we employed a Monte Carlo simulation-based re-sampling mean-variance model to derive asset allocation for each cohort that satisfy the target rate of return while minimizing risks. Our result shows that the target rate of return for each cohort ranged from 6.4% to 6.85%, and it decreased as the generations advanced due to a decrease in the income replacement rate of the National Pension. Consequently, the allocation of risky assets, such as stocks, was relatively reduced in the portfolios of future generations. This study holds significance in that it departs from the macroeconomic-based asset allocation methodology and proposes investments from an asset-liability management perspective, which considers the characteristics of subscribers' liabilities.

• Journal of the Korean Society of Radiology
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• v.84 no.3
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• pp.666-675
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• 2023

Purpose This study aimed to determine whether the attenuation coefficient (AC) from attenuation imaging (ATI) was correlated with visual US assessment in patients with hepatic steatosis. Moreover, it aimed to assess whether the patient's blood chemistry results and CT attenuation were correlated with AC. Materials and Methods Patients who underwent abdominal US with ATI between April 2018 and December 2018 were included in this study. Patients with chronic liver disease or cirrhosis were excluded. The correlation between AC and other parameters, such as visual US assessment, blood chemistry results, liver attenuation, and liver-to-spleen (L/S) ratio, were analyzed. AC values according to visual US assessment grades were compared using analysis of variance. Results A total of 161 patients were included in this study. The correlation coefficient between US assessment and AC was 0.814 (p < 0.001). The mean AC values for the normal, mild, moderate, and severe grades were 0.56, 0.66, 0.74, and 0.85, respectively (p < 0.001). Alanine aminotransferase levels were significantly correlated with AC (r = 0.317, p < 0.001). The correlation coefficients between liver attenuation and AC and between L/S ratio and AC were -0.702 and -0.626, respectively (p < 0.001). Conclusion Visual US assessment and AC showed a strong positive correlation with the discriminative value between the groups. Computed tomography attenuation and AC showed a strong negative correlation.

• Journal of Soil and Groundwater Environment
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• v.10 no.6
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• pp.20-31
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• 2005

Three dimensional Monte-Carlo simulations of non-ergodic transport of a lion-reactive solute plume by steady-state groundwater flow under a uniform mean velocity in isotropic heterogeneous aquifers were conducted. The log-normally distributed hydraulic conductivity, K(x), is modeled as a random field. Significant efforts are made to reduce tile simulation uncertainties. Ensemble averages of the second spatial moments of the plume and plume centroid variances were simulated with 1600 Monte Carlo runs for three variances of log K, ${\sigma}_Y^2=0.09,\;0.23$, and 0.46, and three dimensionless lengths of line plume sources normal to the mean velocity. The simulated second spatial moment and the plume centroid variance in longitudinal direction fit well to the first order theoretical results while the simulated transverse moments are generally larger than the first order results. The first order theoretical results significantly underestimated the simulated dimensionless transverse moments for the aquifers of large ${\sigma}_Y^2$ and large dimensionless time. The ergodic condition for the second spatial moments is far from reaching in all cases simulated, and transport In transverse directions may reach ergodic condition much slower than that in longitudinal direction. The evolution of the contaminant transported in a heterogeneous aquifer is not affected by the shape of the initial plume but affected mainly by the degree of the heterogeneity and the size of the initial plume.