• Horticulture, Environment, and Biotechnology : HEB
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• v.59 no.6
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• pp.899-907
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• 2018

The methanol extracts of flowers obtained from 67 plant species were screened for their inhibitory activity on aldose reductase (AR). Alnus japonica, Aster spathulifolius, Chionanthus retusus, Morus bombycis, Crysanthemum boreale, Persicaria tinctoria, Platycarya strobilacea, and Serratula coronata var. insularis exhibited potent aldose reductase inhibitory (ARI) activity. HPLC-UV analysis of quercetin, an AR inhibitory flavonoid, was performed on extracts showing strong ARI activity. Quercetin was detected in C. retusus, C. boreale, P. tinctoria, and S. coronata var. insularis at concentrations of 1.33, 1.56, 0.82, and $3.37mg\;g^{-1}$ extract, respectively, indicating that quercetin contributed to the ARI activity of these extracts. In the samples in which quercetin was absent, other compounds may be responsible for their potent ARI activity. These results serve as a basis for further studies regarding the bioactive components responsible for the inhibitory effects of various flower extracts on AR activity.

• Journal of electromagnetic engineering and science
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• v.14 no.2
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• pp.47-53
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• 2014

This paper presents a high gain and high harmonic rejection low-noise amplifier (LNA) for software-defined radio receiver. This LNA exploits the high quality factor (Q) series resonance technique. High Q series resonance can amplify the in-band signal voltage and attenuate the out-band signals. This is achieved by a source impedance transformation. This technique does not consume power and can easily support multiband operation. The chip is fabricated in a $0.13-{\mu}m$ CMOS. It supports four bands (640, 710, 830, and 1,070MHz). The measured forward gain ($S_{21}$) is between 12.1 and 17.4 dB and the noise figure is between 2.7 and 3.3 dB. The IIP3 measures between -5.7 and -10.8 dBm, and the third harmonic rejection ratios are more than 30 dB. The LNA consumes 9.6 mW from a 1.2-V supply.

• Journal of Korean Biological Nursing Science
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• v.16 no.2
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• pp.80-89
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• 2014

Purpose: The purpose of this study was to investigate relationships between short sleep, obesity, and screen time. Methods: Data were obtained from a survey using a sample of 1,166 academic, and 597 vocational high school students. A structured questionnaire was used to assess demographics, hours spent in sleep, TV viewing, internet usage, and game playing. Obesity was determined using the body mass index. Descriptive statistics, Cochran Mantel Haenszel Chi-square test, and multiple logistic regression with dummy variables were performed. Results: Short sleep (<8 hours/day) was significantly related to obesity, not in academic school students, but in vocational school students. Academic high school students who had enough sleep (${\geq}8$ hours/day), had more time spent on TV viewing, internet usage, and game playing. Similar results were found in vocational high school students except for internet use. Interestingly, students with better school performance spent significantly less time in TV viewing, internet usage, and game playing, and therefore had a lower risk of obesity in academic school students. Conclusion: There is a significant relationship between short sleep and obesity that was found only in vocational high school students. The relationship between short sleep and screen time was not significant in Korean high school students.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.30 no.4
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• pp.153-160
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• 2019

Objectives: This study aimed to evaluate the addiction to highly caffeinated drinks among university students, and we investigated the relationships between smartphone addiction, depression, anxiety, attention-deficit/hyperactivity disorder (ADHD), burnout, self-esteem, impulsiveness in high caffeine drink addiction risk group (high caffeine group). We also compared these mental health factors differences between the high caffeine group and the control group; and, investigated the relative risk between the independent variables of the high caffeine group. Methods: This study was conducted in Korea, from June 2015 to July 2016. A set of questionnaires was administered on 511 college students. Results: The participants who belonged to the high caffeine group were more likely to demonstrate the symptoms of ADHD and higher levels of burnout and impulsiveness. Further, the results of logistic regression analysis confirmed the association between the high caffeine group and burnout. Conclusion: These behaviors among university students addicted to highly caffeinated drinks suggests the need for timely and effective interventions for those at risk of addiction.

• Geomechanics and Engineering
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• v.31 no.6
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• pp.557-571
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• 2022

Landslides are often triggered by weak interlayers initiated in tailings dam foundations, and hazards gradually occur. This is serious for landslides in high tailings dams due to their high potential energy. Tailing samples with a fine-grained interlayer at a set dip angle were prepared. Consolidated undrained (CU) triaxial shear tests were carried out by using a high-pressure triaxial apparatus. The results were compared with the results under a low confining pressure. Four reasons were summarized for high tailings dams more prone to instability than low dams. The shear strength of the samples with dipping interlayers decreases with increasing dip angle. An obvious straight drop in the stress path after the peak occurs in samples with dipping interlayers at an angle of 60°. The effect of the interlayer on the mechanical behaviour of tailings is very sensitive, especially for the sample with a dipping interlayer at an angle of 60°. Shear slipping along the interlayer should be given more attention in tailings dams. Compared with the results under low confining pressure, the stress decreases continuously for the samples with dipping interlayers at large angles under high confining pressure. The positive pore pressure, which reduces the effective stress, occurred in tailings samples under high confining pressure. The residual strength of tailings under high confining pressure is smaller than that under low confining pressure. These factors increase the dam break risk and the disaster impact for high tailings dams.

• Journal of The Korean Association For Science Education
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• v.15 no.4
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• pp.437-451
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• 1995

Middle and high school students' conceptual understanding about stoichiometry, gas laws, and diffusion was compared with essay type test and multiple choice test. Whereas achievement of high school students was higher in stoichiometry, that of middle school students who were expected to go to high schools was higher in gas laws and diffusion. When students' achievement was compared to that of American college students, Korean students' achievement was higher in stoichiometry and was similar in gas laws. These results indicate that algorithmic problem solving is more emphasized than conceptual understanding in high schools and that quantitative aspects focused in chemistry education are not helpful in concept understanding. Nevertheless relatively smaller difference between concept understanding and algorithmic problem solving for high school students in this study seems to be from concept learning in middle schools.

• Journal of Ginseng Research
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• v.35 no.3
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• pp.308-314
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• 2011

In the present study, we investigate anti-diabetic effect of pectinase-processed ginseng radix (GINST) in high fat diet-fed ICR mice. The ICR mice were divided into three groups: regular diet group, high fat diet control group (HFD), and GINSTtreated group. To induce hyperglycemia, mice were fed a high fat diet for 10 weeks, and mice were administered with 300 mg/kg of GINST once a day for 5 weeks. Oral glucose tolerance test revealed that GINST improved glucose tolerance after glucose challenge. Compared to the HFD control group, fasting blood glucose and insulin levels were decreased by 57.8% (p<0.05) and 30.9% (p<0.01) in GINST-treated group, respectively. With decreased plasma glucose and insulin levels, the insulin resistance index of the GINST-treated group was reduced by 68.1% (p<0.01) compared to the HFD control group. Pancreas of GINST-treated mice preserved a morphological integrity of islets and consequently having more insulin contents. In addition, GINST up-regulated the levels of phosphorylated AMP-activated protein kinase (AMPK) and its target molecule, glucose transporter 4 (GLUT4) protein expression in the skeletal muscle. Our results suggest that GINST ameliorates a hyperglycemia through activation of AMPK/GLUT4 signaling pathway, and has a therapeutic potential for type 2 diabetes.

• Nutrition Research and Practice
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• v.5 no.1
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• pp.11-19
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• 2011

Eotaxin is an important inflammatory chemokine in eosinophil chemotaxis and activation and, thus, is implicated in asthma. Recently, obesity was associated with an increased prevalence of asthma, but the relationship between obesity and eotaxin expression has only been partially understood in obese mice and human studies. Therefore, we studied the expression patterns of eotaxin in 3T3-L1 preadipocytes/adipocytes to determine whether eotaxin levels are influenced by body weight gain and/or reduction in diet-induced obese mice. First, we investigated eotaxin expression during differentiation in 3T3-L1 adipocytes. Then, we treated 3T3-L1 preadipoeytes/adipoeytes with tumor necrosis factor-alpha (TNF-${\alpha}$), eotaxin, interleukin (IL)-4, IL-5, or leptin. To examine the effects of weight loss in high-fat diet induced obese mice, we fed C57BL/6 mice a high-fat diet or a normal diet for 26 weeks. Then, half of the high-fat diet group were fed a normal diet until 30 weeks to reduce weight. Epididymal adipose tissue, visceral adipose tissue, serum, and bronchoalveolar fluid of mice were examined for eotaxin expression. The results showed that eotaxin expression levels increased with adipocyte differentiation and that more eotaxin was expressed when the cells were stimulated with TNF-${\alpha}$, eotaxin, IL-4, IL-5, or leptin. An in vivo study showed that eotaxin levels were reduced in visceral adipose tissues when high-fat diet fed mice underwent weight loss. Taken together, these results indicate a close relationship between eotaxin expression and obesity as well as weight loss, thus, they indirectly show a relation to asthma.

• Journal of The Korean Association For Science Education
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• v.21 no.4
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• pp.677-688
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• 2001

The purposes of this study are to investigate the school science high achievers' achievements in enrichment physics, logical thinking level, and to analyze the relationship between logical thinking level and the achievement in enrichment physics of high achievers in science. The subjects were 357th and 8th graders who achieved highly in school science. To assess their achievements in enrichment physics, we developed a new test consisting of descriptive problems which were based on middle school curriculum. Those problems require one or two steps of thinking process, not simple knowledge of science. To assess logical thinking level, we used the instrument called GALT(Group Assessment of Logical Thinking) developed by Roadranka et al. The results showed that the school science high achievers' average achievement in enrichment physics was low, 56.3 out of 150, which indicated that they had not done much of enrichment learning beyond middle school science curriculum. Just only 54% of the school science high achievers are in formal logical thinking level. From the analysis of relationship between their logical thinking level and the achievement in enrichment physics, the value of the correlation coefficient was 0.174, which means that they are not almost correlated. Therefore, it is not desirable to judge science gifted children just from achievement in school science or enrichment physics, so both(logical thinking and the achievement in enrichment physics) tests should be taken for selecting gifted student.

• Hwankyungkyoyuk
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• v.10 no.2
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• pp.101-120
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• 1997

The objective of this research is to understand the current field and composition of environment related terminology used in middle and high school textbooks, to find out uniformity and relationship between them, and development for the future establishement and replacement in the environmental education, simultaneously. The results of this study are as follows: 1. The terms used in middle school textbooks were found out to be 334, while those used in high school were 717. Total terms used were 870(759 kinds) and those recorded in the environmental terminology dictionary were 362 including synonyms. 2. Of those 870, 211 terms (24.25%) which were the same words have been used in interlinked connection with the Middle and High schools. While 136 terms(15.63%) have been used in the only middle, and 524 terms(60.23%) have been used in the only high schools. In middle and high school environmental text books 211 (24.25%) terms were the same interlinked terms. Of those extracted terms, 136(15.63%) were used in the middle school 'environmental' textbooks and in high school, 524(60.23%) were used in 'environmental science' book. These results shows that there is big gap between middle and high school contents and we will need more consideration in selecting the terms and better substance. 3. The same terminologies used in both middle and high schools were total number of 676. In those terms 257 kinds(76.26%) were used in middle school 'environmental' text books, and 563 kinds(78.52%) in high school 'environmental science' text books. Here are some details : 1) Terms used as same meaning but different in expression in middle school: 83 kinds, 192 terms (11.99%). 2) Differently expressed in the same text book : in middle school - 20 kinds(2.64%) in high school - 61 kinds(8.04%) 3) Differently expressed terms between middle and high school: 51 kinds(6.72%) 4) Same meaning in 3 expressions or more : 19 kinds 4. Of the examined terms 362(including 43 synonyms) were defined in environmental dictionary which is 41.8% of the total words. In the future specialization in utmost fields will be needed 5. When dividing those examined terms according to the middle and high school curriculum, the most terms were used in nature and pollution fields following environmental preserving, artificial environment, and environmenatal counterplan. In middle schools the most used terms were in the field of environment pollution, preservation, counterplan, and sanitation. These results reflects the education goals and objectives of middle schools. But for the middle school 'environment' curriculum moret uniform distribution are needed and for the high schools' 'environmental science' program, the fields in artificial environment, industrization, urbanization, and sanitation should be intensified.