• Journal of the Korean earth science society
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• v.31 no.2
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• pp.164-171
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• 2010

The purpose of this study was to investigate the effects of instruction applying 3D Planetarium Software (Starry Night Pro 6.0) in terms of the learners' science achievement, changes of attitude (attitude toward science as well as scientific attitude), and self-directed learning ability. Participants were 198 $8^{th}$ graders. This study adopted a quasi-experimental research design in which experimental group was taught with 3D planetarium software vs. control group with traditional lecture-centered teaching method for 6 hours. The effects were investigated by independent sample t-test and paired sample t-test The results are as follows. The instruction using 3D planetarium software was more effective than the traditional lecture-centered curriculum in science achievement and self-directed learning ability. However, there were not meaningful differences in analyzing attitudes related science, the results that were so effective in elevation for self-directed learning could be gained. Students were interested in instruction applying 3D planetarium software, which was helpful for them to understand the content knowledge. Results showed that instruction with 3D planetarium software applied was effective in $8^{th}$ grade science learning.

• Journal of the Korean Institute of Gas
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• v.1 no.1
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• pp.27-32
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• 1997

Continual monitoring of abnormal operating conditions i a key issue in maintaining high product quality and safe operation, since the undetected process abnormality may lead to the undesirable operations, finally producing low quality products, or breakdown of equipment. The statistical projection method recently highlighted has the advantage of easily building reference model with the historical measurement data in the statistically in-control state and not requiring any detailed mathematical model or knowledge-base of process. As the complexity of process increases, however, we have more measurement variables and recycle streams. This situation may not only result in the frequent occurrence of process Perturbation, but make it difficult to pinpoint trouble-making causes or at most assignable source unit due to the confusing candidates. Consequently, an ad hoc skill to monitor and diagnose in plat-wide scale is needed. In this paper, we propose a hierarchical plant-wide monitoring methodology based on hierarchical decomposition and principal component analysis for handling the complexity and interactions among process units. This have the effect of preventing special events in a specific sub-block from propagating to other sub-blocks or at least delaying the transfer of undesired state, and so make it possible to quickly detect and diagnose the process malfunctions. To prove the performance of the proposed methodology, we simulate the Tennessee Eastman benchmark process which is operated continuously with 41 measurement variables of five major units. Simulation results have shown that the proposed methodology offers a fast and reliable monitoring and diagnosis for a large scale chemical plant.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.456-467
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• 2018

Appearance has become an important means of expressing oneself in modern society, and women often desire to lose weight. Therefore, this study examined the diets of female college students with high weight loss needs and analyzed the effects of their body image, sociocultural attitude, body stress and diet behavior on intake weight loss products. Data were collected from 220 Korean female college students from June to July using an online survey program. The questionnaires included body image scale, Sociocultural Attitude Towards Appearance Questionnaire (SATAQ), Body Attitudes Questionnaire (BAQ) and diet behaviors scale. Data were analyzed by descriptive statistics, the $x^2$-test, Pearson's correlation coefficients, and logistic regression analysis using the SPSS 22.0 program. There were significant differences in body image, SATAQ, obesity stress and diet behavior between groups. All variables were significantly correlated with each other. Factors influencing weight loss products intake by female university students were SATAQ (OR=1.15, CI=1.03-1.29), obesity stress (OR=1.13, CI=1.06-1.20), diet behaviors (OR=1.21, CI=1.10-1.33), and knowledge regarding the side effects of weight loss products (OR=3.86, CI=1.62-9.20). Thus, it is necessary to teach female college students to recognize healthy weight control methods. Moreover, if weight loss products are needed, appropriate information should be provided regarding the ingredients and side effects of the product.

• The Korean Journal of Community Living Science
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• v.24 no.3
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• pp.411-427
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• 2013

To investigate the comparison of dietary status and health behaviors according to obesity, 239 male workers were selected and classified as normal (18.5-22.9 27.2%), overweight (23-24.9, 37.7%), and obese (25-29.9, 35.2%) by body mass index ($kg/m^2$). The SAS (ver. 9.2) program was used and verified by the chi-square and f-value methods. Drinking frequency(2-3 times a week) was higher in normal males(45.3%), but not as high as in obese males (48.1%) (p<0.001). Smoking frequency and amount were the highest in overweight males, but not-quit-smoking was high in obese males(51.9%) (p<0.001). Exercise time was longer in normal males(108 minutes) than other groups(69 overweight males, and 82 obese males (p<0.01). Obese groups(73.8%) slept well (p<0.001), but overweight males(44.4%) showed less than 6 hours of sleep (p<0.01). Meal frequency differed by group(two meals a day 67.7% in normal males (p<0.001), no-snack 65.5% in obese males(p<0.001). The frequency of eating-out was once a day in normal males (38.5%), differed in the eating-out time (lunch(45.8%) in normal males, dinner in overweight males(52.1%) and obese males(59.5%) (p<0.01). Korean food (49.3%) was selected, but noodle differed by group(10.2% normal 21.5% obese (p<0.01). Self-perception of body differed from the body's actual condition(p<0.001). For weight control, exercise(56.4%) was practiced more than diet(18.6%). Nutrition knowledge was poor (correct answer rate was 36.7% in normal males, 41.7% in overweight males, and 46.7% in obese males). For eating attitudes, obese males answered more in "flexible to change eating habits", "supplemented when poor eating"(p<0.001), normal responded in "impact on nutrition to health", "try new food for health"(p<0.01). From these results, it is evident that male workers, especially overweight ones, must work to learn more about health and nutrition so as to combat chronic diseases.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.1
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• pp.1-9
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• 2020

Objectives: The purpose of this case study is to assess workers' exposure to carbon nanotubes(CNTs) and characterize particles aerosolized during the process of producing CNT-enabled polytetrafuoroethylene(PTFE) composites at a worksite in Korea. Methods: Personal breathing zone and area samples were collected for determining respirable concentrations of elemental carbon(EC) using NIOSH(National Institute for Occupational Safety and Health) Method 5040. Personal exposure to nano-sized particles was measured as the number concentration and mean diameter using personal ultrafine particle monitors. The number concentration by particle size was measured using optical particle sizers(OPS) and scanning mobility particle sizers(SMPS). Transmission electron microscopy (TEM) area samples were collected on TEM grids and analyzed to characterize the size, morphology, and chemistry of the particles. Results: Respirable EC concentrations ranged from 0.04 to 0.24 ㎍/㎥, which were below 23% of the exposure limit recommended by NIOSH and lower than background concentrations. Number concentrations by particle size measured using OPS and SMPS were not noticeably elevated during CNT-PTFE composite work. Instant increase of number concentrations of nano-sized particles was observed during manual sanding of CNT-PTFE composites. Both number concentrations and mean diameters did not show a statistically significant difference between workers handing CNT-added and not-added materials. TEM analyses revealed the emission of free-standing CNTs and CNT-PTFE aggregate particles from the powder supply task and composite particles embedded with CNTs from the computer numerical control(CNC) machining task with more than tens of micrometers in diameter. No free-standing CNT particles were observed from the CNC machining task. Conclusions: Significant worker exposure to respirable CNTs was not found, but the aerosolization of CNTs and CNT-embedded composite particles were observed during handing of CNT-PTFE powders and CNC machining of CNT-PTFE composites. Considering the limited knowledge on the toxicity of CNTs and CNT composite particles to date, it seems prudent to take a precautionary approach for the protection of workers' health.

• Journal of Educational Research in Mathematics
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• v.17 no.1
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• pp.67-90
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• 2007

The purpose of this study is to understand students' thinking process in the algebra problem solving, on the base of the works of Vinner(1997a, 1997b). Thus, two middle school students were evaluated in this case study to examine how they think to solve algebra word problems. The following question was considered to analyze the thinking process from the similarity-based perspective by focusing on the process of solving algebra word problems; What is the relationship between similarity and the characteristics of thinking process at the time of successful and unsuccessful problem solving? The following results were obtained by analyzing the success or failure in problem solving based on the characteristics of thinking process and similarity composition. Successful problem solving can be based on pseudo-analytical thought and analytical thought. The former is the rule applied in the process of applying closed formulas that is constructed structural similarity not related with the situations described in the text. The latter means that control and correction occurred in all stages of problem solution. The knowledge needed for solutions was applied with the formulation of open-end formulas that is constructed structural similarity in which memory and modification with the related principles or concepts. In conclusion, the student's perception on the principles involved in a solution is very important in solving algebraic word problems.

• The Journal of the Korean Society for Microbiology
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• v.17 no.1
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• pp.35-41
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• 1982

Enterotoxigenk E. coli is one of the major causative agents of the infantile diarrhea and traveler's diarrhea. The heat-labile enterotoxin is thought to be a virulence factor in the pathogenesis of the diarrhea and to be a marker for identification of the enterotoxigenic E. coli from non pathogenic E. coli. Therefore knowledge about the heat-labile enterotoxin is essential not only for understanding the pathogenesis but also for the diagnosis of the diarrhea. However the in-vitro heat-labile enterotoxin production is reported to be greatly affected by the cultural condition. In this regards, this study was designed to know the optimal conditions for the production of the heat-labile enterotoxin by assaying the permeability factor in the 18 hours culture supernatant of E. coli 08K25(B2) H9 and of E. coli 015 H11. Results obtained were summerized as follows: 1. Amounts of heat-labile enterotoxin produced were greater at initial pH 8.5 than at 7.0 of CYES-2 broth culture. However, the bacterial growth itself was more abundant at 7.0 than at 8.5. 2. Heat-labile enterotoxin per unit volume of culture supernatant was greater at shaking culture than at standing culture condition, but ratio of the enterotoxin produced over the unit mass of E. coli calculated was greater at standing culture than shaking culture condition, indicating that the greater yields of the toxin produced at shaking culture was due to increase in E. coli cell mass compared to the standing culture condition: 3. The enterotoxin produced in the lincomycin(128 microgram/ml) supplemented media was 5 or 11 times greater on the basis of enterotoxin per unit mass of E. coli, compared to the lincomycin-non-supplemented media, indicating that lincomycin itself increases the enterotoxin production. 4. Treatment of 18 hours culture of E. coli with polymyxin B(0.2 mg/ml) for 1 hour increased the yields of enterotoxin amounting to 2 or 5 times of the non-treated control cultures.

• Journal of Microbiology and Biotechnology
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• v.25 no.9
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• pp.1467-1475
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• 2015

The use of microbial extracts containing plant hormones is a promising technique to improve crop growth. Little is known about the effect of bacterial cell-free extracts on plant growth promotion. This study, based on phytohormonal analyses, aimed at exploring the potential mechanisms by which Enterococcus faecium LKE12 enhances plant growth in oriental melon. A bacterial strain, LKE12, was isolated from soil, and further identified as E. faecium by 16S rDNA sequencing and phylogenetic analysis. The plant growth-promoting ability of an LKE12 bacterial culture was tested in a gibberellin (GA)-deficient rice dwarf mutant (waito-C) and a normal GA biosynthesis rice cultivar (Hwayongbyeo). E. faecium LKE12 significantly improved the length and biomass of rice shoots in both normal and dwarf cultivars through the secretion of an array of gibberellins (GA₁, GA₃, GA₇, GA₈, GA₉, GA₁₂, GA₁₉, GA₂₀, GA₂₄, and GA₅₃), as well as indole-3-acetic acid (IAA). To the best of our knowledge, this is the first study indicating that E. faecium can produce GAs. Increases in shoot and root lengths, plant fresh weight, and chlorophyll content promoted by E. faecium LKE12 and its cell-free extract inoculated in oriental melon plants revealed a favorable interaction of E. faecium LKE12 with plants. Higher plant growth rates and nutrient contents of magnesium, calcium, sodium, iron, manganese, silicon, zinc, and nitrogen were found in cell-free extract-treated plants than in control plants. The results of the current study suggest that E. faecium LKE12 promotes plant growth by producing GAs and IAA; interestingly, the exogenous application of its cell-free culture extract can be a potential strategy to accelerate plant growth.

• Magazine of the Korean Society of Agricultural Engineers
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• v.28 no.2
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• pp.31-41
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• 1986

Knowledge of the degree of yield reduction due to water stress at different crop growth stages in rice production is important for rational scheduling of irrigation during periods of insufficient water supply. Previous studies to determine the degree of yield reduction duo to water stress suffered from interruptions by rain during experiment. Also the findings did rot relate the degree of water stress to the soil water potential and water deficit status of rice plants. In this study, two years experiments were conducted using the high yielding rice varieties, an Indica x Japonica (Nampoong) and a Japonica variety(Choochung). These were grown in 1/200$^{\circ}$ plastic pots placed under a rainfall autosensing, sliding clear plastic roof facility to control rainfall interruptions. The results obtained were as follows. 1.The two varieties differed in the growth stage most sensitive to water stress as well as the degree of yield reductions. When rice plants were stressed to the leaf rolling score 4 and soil water potential of about - 20 bar at major crop growth stages which included heading, booting, non-effective tillering, panicle initiation and early tillering stages, the yield reductions in the Indica x Japonica variety were 58%, 34%, 27%, 22%, and 21%, respectively, whereas in the Japonica vairety they were 23%, 36%, 1%, 13% and 22%, respectively. This result show that the recommended drainage during non-effective tillering is valid only for the Japonica variety. Sufficient irrigation at booting, heading and early tillering stages are necessary for both varieties. 2.The two varieties showed visible wilting symptoms when the soil water potential dropped to about - 3.0 bar. The Japonica variety showed more leaf rolling than the Indica X Japonica. However, it had a higher retention of leaf water content and greater stomatal diffusive resistance. When the soil water potential dropped, the Japonica variety showed leaf rolling score (LRS) 1 at 0 soil-5. 0 bar and LRS 2 at 0 soil -6.0 bar while the Indica X Japonica showed LRS 1 at 0 soil - 5.5 bar and LRS 2at 0 Soil - 9.0 bar. The stomatal diffusive resistance was maximum at the second top leaf blade in both varieties at intermediate water stress of 0 soil - 4.5 bar. 3.The number of days that was required for the soil water potential to drop to-3. 0 bar and to - 20.0 bar after drainage of irrigation water from the 20cm deep silty clay loam soil in the pots were 6 and 13 days, respectively for booting stage, and 7 and 11 days, respectively for heading stage, 9 and 12 days, respectively for panicle initiation stage, and 12 and 19 days, respectively for early tillering stage. 4.Water stress during the early tillering stage recorded the longest delay in beading time, the largest reduction in panicle numbers and a substantial yield decrease of 20%. This calls for better water management to ensure the availability of water at this stage, particularly during drought periods. In addition, a reexamination of the conventional inter-drainage practice during the non-effective tillering stage is necessary for the high yielding Indica X Japonica varieties.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.6
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• pp.2333-2340
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• 2015

Background: Due to the strong inhibitory effects of $PPAR{\gamma}$ gene on the growth of cancer cells, the role of Pro12Ala polymorphism in $PPAR{\gamma}$ gene has been extensively investigated in cancer recently. However, the results were inconsistent according to cancer type. The aim of this study was to comprehensively evaluate the $PPAR{\gamma}$ Pro12Ala polymorphism and gastric cancer susceptibility. Materials and Methods: Search strategies were conducted in Pubmed, Medline (Ovid), Chinese biomedical database (CBM), China national knowledge infrastructure (CNKI), VIP, and Wanfang database, covering all publications, with the last search up to November 01, 2014. The strength of association between $PPAR{\gamma}$ Pro12Ala polymorphism and gastric cancer risk was assessed by OR with 95%CI. Results: A total of 546 cases and 827 controls in 5 case-control studies were included in this meta-analysis. The results indicated that the variant G allele carriers (CG+GG) had a 2.31 times higher risk for gastric cancer when compared with the homozygote CC (odds ratio (OR)=2.31, 95% confidence interval (CI)=1.67-3.21 for CG+GG vs. CC). In the subgroup analysis by ethnicity, significantly elevated risks were both found in Asians (OR=2.56, 95% CI=1.42-4.64) and Caucasians (OR=2.20, 95% CI=1.48-3.25). Similarly, in the subgroup analysis by H. pylori status, a significantly increased risk was identified in H. pylori (+) populations (OR=3.68, 95%CI=2.07-6.52), but not in H. pylori(-) populations (OR=1.17, 95%CI=0.58-2.39). Conclusions: This pooled analysis suggested that the $PPAR{\gamma}$ Pro12Ala polymorphism could be an independent predictive risk factor for gastric cancer especially in H. pylori infected populations in Asians and Caucasians. Nevertheless, prospectively designed cohort studies are needed to further investigate gene-gene and gene-environment interactions to confirm the combined effects of $PPAR{\gamma}$ Pro12Ala polymorphisms and H. pylori infection on gastric cancer risk.