• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.4
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• pp.601-610
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• 2016

The light-emitting diode (LED) has been used in a variety of industrial fields and for general 0lighting purposes on account of its high efficiency, low power consumption and long lifespan. The LED is driven by direct current; therefore, an AC/DC converter is typically required for its use. An electrolytic capacitor is generally used for stabilizing DC voltage during use of the AC/DC converter. However, this capacitor has a short lifespan, which makes it a limiting factor in LED lighting. Furthermore, LED lighting requires a dimmable control to enable energy savings and fulfil a growing consumer demand. In this paper, the dimmable single-stage power factor correction (PFC) continuous conduction mode (CCM) flyback converter that employs no electrolytic capacitor is presented. The LC resonant filter is alternatively applied to reduce the 120[Hz] ripple on the output. And the optimum value of the LC resonant filter parameters considering both efficient and performance is analysed. Simulation and experimental results verify the satisfactory operation of the converter.

• Journal of the Speleological Society of Korea
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• no.71
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• pp.1-4
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• 2006

Chloromethylnaphthalene is a valuable compound for obtaining of the plant growing stimulator - -napthylacetic acid. Chloromethylation of naphthalene by paraformaldehyde in the presence of glacial acetic acid, phosphoric and hydrochloric acids at temperature 80 - 85C and duration - 6 hours the -chloromethylnaphthalene yield was 55-57%. Using Box-Wilson method for mathematical planning of experiment carried out optimization of its synthesis for purpose increasing -chloromethylnaphthalene yield. Preliminary, one - factor experiments were carried out for selecting independence main parameters influencing on the synthesis. A full factor experiment of 23 with extended matrix of planning was used for optimization. Aiming to increase the -chloromethylnaphthalene yield, the obtained mathematical model was used for program of sharp raising on the reply surface. The received optimal conditions for the -chloromethylnaphthalene synthesis were selected as following: molar ratio of naphthalene parapfsormaldehyde of 1 : 2 temperature - 105C duration of the reaction - 3 hours. The yield of -chloromethylnaphthalene under these optimal conditions was 75%.

• Biomolecules & Therapeutics
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• v.26 no.1
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• pp.57-68
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• 2018

Nuclear factor E2-related factor 2 (NRF2) plays an important role in redox metabolism and antioxidant defense. Under normal conditions, NRF2 proteins are maintained at very low levels because of their ubiquitination and proteasomal degradation via binding to the kelch-like ECH associated protein 1 (KEAP1)-E3 ubiquitin ligase complex. However, oxidative and/or electrophilic stresses disrupt the KEAP1-NRF2 interaction, which leads to the accumulation and transactivation of NRF2. During recent decades, a growing body of evidence suggests that NRF2 is frequently activated in many types of cancer by multiple mechanisms, including the genetic mutations in the KEAP1-NRF2 pathway. This suggested that NRF2 inhibition is a promising strategy for cancer therapy. Recently, several NRF2 inhibitors have been reported with anti-tumor efficacy. Here, we review the mechanisms whereby NRF2 is dysregulated in cancer and its contribution to the tumor development and radiochemoresistance. In addition, among the NRF2 inhibitors reported so far, we summarize and discuss repurposed NRF2 inhibitors with their potential mechanisms and provide new insights to develop selective NRF2 inhibitors.

• Journal of the Korean Society of Food Culture
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• v.35 no.3
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• pp.311-322
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• 2020

Recently, there is growing interest in studying the dietary patterns that affect the risk of circulatory system diseases (CSDs). We investigated the relationship between CSDs and dietary patterns through a follow-up study in Korea (2001-2016). The participants of this study were obtained from the Korean Genome and Epidemiology Study (KoGES). This study was a large community-based cohort study (the Ansan-Ansung areas) conducted to assess the effects of various factors, especially diet, on the onset of chronic diseases among the Korean population aged 40-69 yrs. Baseline data were collected from 2001 to 2002, and follow-up studies were performed every 2 yrs, with over 7 follow-up studies performed (2015-2016). Three dietary patterns were identified using factor analysis: "vegetable and seafood (men)/soup and stew (women)" pattern, "sweet foods and breads-rice cake" pattern, and "multigrain rice and cooked white rice" pattern. None of the dietary patterns were significantly associated with the risk of CSDs in either men or women. Our follow-up study is meaningful as it investigated whether the dietary patterns of individuals according to sex affects the development of CSDs.

• 한국사회복지학회:학술대회논문집
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• 2005.04a
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• pp.651-673
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• 2005

Political participation consciousness of social worker is changed and politics participation activity is putting forth with a bud. Currently, the systematic and scientific approach in study of social worker's the political participation is short. This study analyzes the present situation of political participation action and will present political participation action contents and direction in the future. This study may give practical meaning to the social welfare practice and educational scope about what we must do to become a political influence the group. The object of this study is 1229 people in choosing social welfare politics participation investigation committee data. A participation of Korean social worker appeared that a meeting or a demonstration is high when comparing the United States. Also, electioneers, and, government bureaucrat contact, financial contributions is a half experience. The strong variable in explaining social worker's the political participation was a politics efficacy, politics interest. Political efficacy and politics interest, a joining and a political behavior proposal of an association is a influenced factor. Through this result The Civic Volunteer Model is a theory to able to explain social worker's the political participation. Approach growing the political efficacy and politics interest is very important in activating politics participation. Role of a social welfare association or a group was important in order to induce politics participation and concentrate.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.3
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• pp.47-55
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• 2016

As smartphone was distributed widely usage of SNS is growing. Because of ots characteristics, SNS can sustain only when user uses SNS, users' intention to persist use of SNS is very important. Therefore in this study, psychological needs and immersion, the quality of SNS were chosen as impact variables to verify whether they affect the persistance of Facebook usage. A survey was conducted to 165 of Facebook user, and the result showed that compentence and relatedness significantly affeted immersino, and compentence and system quality significantly affected Facebook persistence.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.5
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• pp.331-336
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• 2010

In rapidly growing tumors, hypoxia commonly develops due to the imbalance between $O_2$ consumption and supply. Hypoxia Inducible Factor (HIF)-$1{\alpha}$ is a transcription factor responsible for tumor growth and angiogenesis in the hypoxic microenvironment; thus, its inhibition is regarded as a promising strategy for cancer therapy. Given that CamKII or PARP inhibitors are emerging anticancer agents, we investigated if they have the potential to be developed as new HIF-$1{\alpha}$-targeting drugs. When treating various cancer cells with the inhibitors, we found that a CamKII inhibitor, KN-62, effectively suppressed HIF-$1{\alpha}$ specifically in hepatoma cells. To examine the effect of KN-62 on HIF-$1{\alpha}$-driven gene expression, we analyzed the EPO-enhancer reporter activity and mRNA levels of HIF-$1{\alpha}$ downstream genes, such as EPO, LOX and CA9. Both the reporter activity and the mRNA expression were repressed by KN-62. We also found that KN-62 suppressed HIF-$1{\alpha}$ by impairing synthesis of HIF-$1{\alpha}$ protein. Based on these results, we propose that KN-62 is a candidate as a HIF-$1{\alpha}$-targeting anticancer agent.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.3
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• pp.383-392
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• 2014

Purpose: In this study, we sought to understand the risk factor for chronic disease of workers by studying the association between occupational standing time and metabolic syndrome(MetS) in full-time 300 male workers. Materials: Data on age, life habit, work related information of the subjects were surveyed using self-reported questionnaire and interview. MetS was identified based on the report of Alberti et al.(2009). As for the data analysis, SPSS 19.0 was used to conduct the descriptive statistic, ANOVA, Pearson correlation coefficient and multiple logistic regression analysis. Results: Daily working hour affects on the lifting heavy objects, running and strenuous exercise(r=-0.137, p<0.01), and total physical function decreased with the increase in age(r=-0.145, p<0.01). Also, obese was significantly associated with genuflection and bend over(r=-0.110, p<0.05). On multiple logistic regression analysis for the diagnostic indices of MetS, occupational standing time were significantly associated with waist circumference(odds ratio=0.885, ${\beta}$ value=-0.122, 95% CI=0.797-0.983, p<0.05) and triglyceride (odds ratio=0.873, ${\beta}$ value=-0.136, 95% CI=0.800-0.953, p<0.01). Conclusions: These results suggest that the working posture may be important risk factor in pathogenesis and growing of MetS and cardiovascular disease.

• Journal of Soil and Groundwater Environment
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• v.15 no.3
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• pp.27-33
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• 2010

The purpose of this study was in search of native plant species showing metal-resistant property and excessively accumulating heavy metals in metal-contaminated soil or abandoned mines as well as in evaluation of applicability of phytoremediation. In the study area, species showing excessively accumulating heavy metals were a shepherd´s purse, pampas grass, a Korean lettuce, a Hwansam vine, the Korean persicary, a foxtail, a goosefoot, and a water pepper. The first screened plant species in Sambo mine were as shepherd's purse, Korean lettuce and pampas grass Among them the shepherd´s purse can be excluded because it is a seasonal plant and has lower removal capacity for heavy metals. The Korean lettuce was also excluded because of having lower removal capacity for heavy metals. Pampas grass is a highly bionic plant species constantly growing from spring. However it has weak points such as little accumulation capacity for zinc as well as small values of an accumulation factor and a translocation factor. Another problem is regarded as removal of roots after the clean up if pampas grass is applied to a farmland. In Sanyang mine, wormwood and Sorijaengi were considered as adaptable species.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.4
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• pp.349-354
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• 2009

To rationally secure and maintain the safety and serviceability of a high-rise building, monitoring of structural responses of members is necessary. As such health monitoring of large-scale building structures has received growing attention by researchers in recent years. However, due to a very large number of members complexity of structural responses of a high-rise building structure, practical difficulties exist in selection of structural members to be sensored for assessment of structural safety of a structure. In this paper, a selection technique for active members for safety monitoring of a high-rise building based on displacement participation factor and strain energy density of a member is investigated.