• Journal of The Korean Association For Science Education
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• v.43 no.3
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• pp.295-306
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• 2023

In this study, we explored science teachers' perceptions of adaptive practice in terms of importance and practice. For this purpose, an adaptive practice questionnaire was developed targeting secondary science teachers, and the responses of 128 science teachers were analyzed. The results of this study were as follows: First, the science teachers responded that all 17 items regarding adaptive practice were important. In particular, items related to 'addition of examples', 'adjustment of the level/range of concepts', and 'encouragement of student participation' showed high importance and performance levels. Second, the results of the IPA concerning adaptive practice showed that the items needing intensive improvement due to high importance but low performance were 'encouraging students' self-directed learning' and 'monitoring and responding to individual differences'. The science teachers identified a lack of time and uniform curriculum as the reasons for the low level of practice despite the high importance of these items. Third, regarding the IPA of the adaptive practice items, the items located in the fourth area, an excessive area, concerned 'pace control', 'modifying activities', and 'metaphor use'. More specifically, considering that 'metaphor use' was the only item with a higher level of performance than importance, it is necessary to reconsider whether problems are caused by excessive use. Fourth, analyzing the responses regarding the reasons for the difference in importance and performance revealed that the factors related to teachers included teachers' lack of knowledge or ability, and the tendency to implement as planned. As for student factors, an excessive number of students, differences in the levels of students, and a tendency to prefer classes centered on entrance exams were identified. As environmental factors, a uniform curriculum, conditions for experiments, evaluation systems, and external demands were mentioned. Finally, the implications of the results of this study for science education were discussed.

• Journal of Industrial Convergence
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• v.22 no.5
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• pp.57-67
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• 2024

This study conducted to confirm the effect of college students' individual tendencies and psychological variables on the depth of chest pressure during CPR. For this, the depth of chest compression during CPR was measured after investigating individual tendencies, fatigue, performance confidence, and performance anxiety in 127 college students. Multiple linear regression analysis was performed using individual propensity and psychological variables as independent variables and chest compression depth as dependent variables to identify factors affecting chest compression depth. Pearson correlation analysis was performed to confirm the correlation between variables. As a result of the analysis, the higher the performance confidence, the deeper the chest compression depth, and the higher the performance anxiety, the lower the chest compression depth(p<0.05). The depth of chest pressure showed a positive correlation with individual tendencies, performance confidence, while it showed a negative correlation with fatigue and performance anxiety(p<0.01, p<0.05). Based on these results, it is necessary to increase performance confidence and lower performance anxiety in order to perform the correct chest compression depth. For this, various efforts such as program development, education and research are required.

• Journal of The Korean Association For Science Education
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• v.28 no.4
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• pp.316-330
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• 2008

During the past two decades or so, science (or scientific or scientific & technological) culture has become one of the main themes not only of policy makers but also of science educators. Although, the idea of science culture has been taken as a desirable goal, there is little agreement about what it means and how to measure it. Particularly in Korea, there has been a rapid growth of science culture projects and programs, either by governmental or non-governmental, but with little systemic monitoring and evaluation for its practice. The purpose of this study is, thus, to explore a model of measuring science culture and develop a comprehensive indicator system for it. We reviewed many literatures on definitions of science culture and the surveys for related terms, particularly, of recent national and international surveys (e.g. US Science and Engineering Indicators, Eurobarometer, Japanese Science and Technology Indicators). Based on this review, a model for science culture is proposed and then used to define the Science Culture Indicators (SCI). This model encompasses two dimensions(i.e. individual and social), which are further divided into two aspects (i.e. potential and practice). Each dimension is expected to represent citizen literacy of and national infrastructure of science culture respectively. Each category in this $2{\times}2$ matrix is further divided into several sub-categories. The discussion concerning how the model and the indicators can be used to check the states of science culture at social as well as individual levels will be given with some concrete examples, such as indicators particularly related to science education.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.4
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• pp.312-316
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• 2014

Purpose: The aim of this study was to compare the fracture toughness of currently available resin cements for zirconia restorations and evaluate the effect of water storage on fracture toughness of those resin cements. Materials and methods: Single-edge notched specimens ($3mm{\times}6mm{\times}25mm$) were prepared from three currently available dual cure resin cements for zirconia restorations (Panavia F 2.0, Clearfil SA luting and Zirconite). Each resin cement was divided into four groups: immersed in distilled water at $37^{\circ}C$ for 1 (Control group), 30, 90, or 180 days (n=5). Specimens were loaded in three point bending at a cross-head speed of 0.1 mm/s. The maximum load at specimen failure was recorded and the fracture toughness ($K_{IC}$) was calculated. Data were analyzed using one-way ANOVA and multiple comparison $Scheff{\acute{e}}$ test (${\alpha}$=.05). Results: In control group, the mean $K_{IC}$ was $3.41{\pm}0.64MN{\cdot}m^{-1.5}$ for Panavia F, 2.0, $3.07{\pm}0.41MN{\cdot}m^{-1.5}$ for Zirconite, $2.58{\pm}0.30MN{\cdot}m^{-1.5}$ for Clearfil SA luting respectively, but statistical analysis revealed no significant difference between them. Although a gradual decrease of $K_{IC}$ in Panavia F 2.0 and gradual increases of KIC in Clearfil SA luting and Zirconite were observed with storage time, there were no significant differences between immersion time for each cement. Conclusion: The resin cements for zirconia restorations exhibit much higher $K_{IC}$ values than conventional resin cements. The fracture toughness of resin cement for zirconia restoration would not be affected by water storage.

• Journal of dental hygiene science
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• v.9 no.3
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• pp.295-302
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• 2009

The purpose of this study is to provide fundamental data for managing occupational stress and promoting health by investigating the factors of dental hygienists' occupational stress and the relationship among occupational stress, health status and somatization. The subjects in this study are 28 dental hygienists who have worked at dental clinic in the metropolitan area. The findings of this study are as follows: 1. The average age of the subjects is 25.1 and the average working career is 42.8 months. 8-9 hours is the most frequent average working time as 55.5% and a 6-day workweek appears most frequently with 33.8%. 2. The total average of occupational stress is 45.24 points and out of the seven sub-factors, job demand is the highest as 56.17 points. 3. A group of working at dental university hospitals scores significantly high and a group of working over 10 hours per day scores significantly low in health status (p<0.05). 4. A group of a 5-day workweek. night and holiday duty scores 18.64 which is significantly high in somatization(p<0.05). 5. Occupational stress have slightly negative correlation (-.341, p<0.01) with health status and slightly positive correlation (.330, p<0.01) with somatization. There is a strong, negative correlation between health status and somatization(-.762, p<0.01 ). 6. Health status and somatization have a slightly positive correlation with every other sub-factor of occupational stress except job self-control.

• Journal of The Korean Society of Grassland and Forage Science
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• v.11 no.4
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• pp.236-243
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• 1991

A field experiment was conducted during the growing season of 1985 to determine the effects of slope orientation, north and south facing exposures and three different altitudes, 800, 1,000 and 1,200m a.s.1. on the dry matter yield, forage quality and botanical composition of alpine pasture. 1. Total dry matter yield of alpine pasture was influenced by slope orientation and altitude. An average forage yield of both exposures at 1,000m a.s.1. was 9,301kg/ha compared with 10,274kg/ha at 800m a.s.1. and the productivity express in relative percentage decreased by 9.5% per 200m attitudinal increase. 2. An average forage yield of both altitudes, 800 and 1,000m a.s.1. on the south facing exposure was 21.5% higher than that on the north exposure. 3. Crude protein concentration of forage grown on both exposures was lowest at 800m a.s.1. increasing gradually as the altitude increased, but crude fiber concentration decreaced in a manner opposite to that of crude protein. 4. Forage grown on the north facing exposure had a higher concentration of crude protein than that grown on the south facing exposure at the same altitude, but lower concentraion of crude fiber. 5. Orchardgrass and timothy were two main species on both exposures at 800m a.s.1. but timothy was only dominant species at 1,000 and 1,200m a.s.1. and performed well up to 1,200m a.s.1. in alpine area. The economic production limit of orchardgrass would be about 800m a.s.1. in the alpine pasture. 6. No soil property differences were found between the north and south facing exposures as well as three different altitudes in the alpine pasture. It seemed that the previous pasture fertilization of the experimental field completely overshadowed any soil property differences from slope orientation and altitude.

• Journal of The Korean Association For Science Education
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• v.37 no.3
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• pp.507-521
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• 2017

The purpose of this study is to investigate a meaningful path model among the components of students' positive experiences about science and science learning to understand the interactive relationships among different variables of affective domains. Positive Experiences about Science (PES) means whole experiences that have positive effects on students' affectional achievement related with science learning, which consists of science academic emotion, science-related self-concept, science learning motivation, science-related attitude, and science-related career aspiration. We conducted an online survey with 1,841 students consisting of 4th, 6th, 8th, and 10th graders from 17 provinces and cities using Test for Indicators of Positive Experiences about Science (TIPES). To explore the structural relationships among variables, we selected and analyzed an optimal structural equation model and then conducted multigroup analyses among groups. According to the analysis of the structural equation model, 'positive as well as negative science academic emotion' has effects on science learning motivation, science-related attitude, and science-related career aspiration via science-related self-concept. According to the independent t-test results for TIPES scores by participants' characteristics, there were statistically significant differences in the average scores of five sub-components of PES depending on gender, school-level, school location, and participation in science-related activities. According to the multi-group analysis results, the difference of path coefficients by gender and school-level were statistically significant, whereas the difference of path coefficients by school location and participation were not significant. Discussed in the conclusion are the implications of this research for science education research and ways to help students' affectional achievement related with science learning.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.2
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• pp.82-89
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• 2014

Purpose: The purpose of this study was to observe the change of viscoelastic properties of dental resin cements during polymerization. Materials and methods: Six commercially available resin cement materials (Clearfil SA luting, Panavia F 2.0, Zirconite, Variolink N, RelyX Unicem clicker, RelyX U200) were investigated in this study. A dynamic oscillation-time sweep test was performed with AR1500 stress controlled rheometer at $32^{\circ}C$. The changes in shear storage modulus (G'), shear loss modulus (G"), loss tangent (tan ${\delta}$) and displacement were measured for twenty minutes and repeated three times for each material. The data were analyzed using one-way ANOVA and Tukey's post hoc test (${\alpha}$=0.05). Results: After mixing, all materials demonstrated an increase in G' with time, reaching the plateau in the end. RelyX U200 demonstrated the highest G' value, while RelyX Unicem (clicker type) and Variolink N demonstrated the lowest G' value at the end of experimental time. Tan ${\delta}$was maintained at some level and reached the zero at the starting point where G' began to increase. The tan ${\delta}$and displacement of the tested materials showed similar pattern in the graph within change of time. The displacement of all 6 materials approached to zero within 6 minutes. Conclusion: Compared to other resin cements used in this study, RelyX U200 maintained plastic property for a longer period of time. When it completed the curing process, RelyX U200 had the highest stiffness. It is convenient for clinicians to cement multiple units of dental prostheses simultaneously.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.1
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• pp.87-94
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• 2012

We evaluated the bioavailability of a novel organic Ca supplement chelated with milk protein (CaMP) in growing rats and compared it with those of Ca carbonate and Ca citrate. Four-week-old male rats were divided into six groups (n=6/group) and fed AIN-93G-based experimental diets containing three Ca sources, Ca carbonate, Ca citrate, and CaMP at two levels, normal (0.5%, w/w) and high (1.5%, w/w), for 6 weeks. Growth, mineral contents of serum, Ca content and breaking force of femur, and Ca absorption were measured. There were no significant differences in weight gain or food intake, but food efficiency ratio (FER) of CaMP in the high Ca group was higher than those of other groups. Ca and P concentrations in serum were within normal range in all experimental rats. There was no difference in Ca content of the femur among all of the groups. Although there was no statistical significance in bone breaking force of the femur among the groups, the CaMP groups had a higher breaking force compared to other groups. Further, Ca absorption rate significantly increased in the CaMP groups (p<0.05). These results demonstrate that the CaMP supplement did not exhibit any negative effect on growth or Ca metabolism of the rats. Therefore, CaMP can be recommended as a good Ca supplement with regard to bone metabolism and Ca bioavailability.

• Journal of Dairy Science and Biotechnology
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• v.34 no.2
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• pp.117-135
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• 2016

The present study was performed to develop a functional raw food material from hydrolyzed whey protein powder (23%-GNANA) medication containing sialic acid as a marker compound that is naturally occurring at 7% concentration in GMP (glycomacropeptide). GMP is used worldwide in foodstuffs for babies and infants and is obtained from the milk protein as safe food. While the purpose of our detailed evaluation was aimed to assess preliminary NOAEL values for and above 2,000 mg/kg/day, a clinical dose allowance for 23%-GNANA (as per characteristic of a functional health product, a highly refined test substance of 23% (v/v) sialic acid combined in GMP), at the same time we also wanted to assess the safety of GMP hydrolyzate lacking sialic acid but with identical properties as GMP. Animal safety evaluation was conducted using 23%-GNANA as the test substance, produced from hydrolyzed whey protein powder (product name: HELICOBACTROL-23; provided by Medinutrol Inc. [Korea]; composed of 23% sialic acid and GMP protein) after isolating the sialic acid using enzymes approved as food additives, with GMP as a raw material, and subsequently increasing the content of xx up to 23% through 80% (v/v) ethanol soaking and concentrating, in accordance with GLP Guideline. The animal safety evaluation mentioned above was made on the basis of toxicity in SPF Sprague-Dawley female and male rats dosed with 10 mL of the test substance diluted to 0, 1,250, 2,500, and 5,000 mg/kg directly into their stomachs for 90 d. This was determined in terms of the general symptoms and animal viability, weight and amount of feed intake, eye examination, uracrasia tests, hematological and blood biochemical disorder tests, blood coagulation test, abnormal intestine weight, abnormalities during postmortem and histopathological examinations. Statistical significance was set at P<0.05. Based on the toxicity determination, a certain minor effect associated with the test substance was observed in male rats with no major effects of the tested substance, in comparison with the control group dosed with sterilized water. Nevertheless, the NOAEL value, evaluated as per toxicity criteria, was verified as 5,000 mg/kg/day (P<0.05). Similarly, for female rats, a certain minor effect associated with the test substance was observed in 5,000 mg/kg/day dosed group, with no major effect, yet the NOAEL value (as assessed as per toxicity criteria) was determined to be 5,000 mg/kg/day (P<0.05), which was the same as for male rats. Accordingly, the NOAEL values of the test substances for all female and male rats were finally verified as 5,000 mg/kg/day (P<0.05). In conclusion, it was determined that the 23%-GNANA test substance exceeds 2,000 mg/kg/day, the clinical allowance characteristic for functional health food, and was finally evaluated to cause no safety concerns when used as a raw material in functional health food production, which was the ultimate goal of the present study.