• Journal of Korean Dental Hygiene Science
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• v.6 no.2
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• pp.101-114
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• 2023

Background: This study aimed to explore the overall perception of pit and fissure sealants and suggest methods to revitalize their current stagnation. Methods: To determine the social perception of the change in coverage policy for pit and fissure sealants, we categorized them into five time periods. The first period (December 1, 2009 to November 30, 2010), the second period (December 1, 2010 to September 30, 2012), the third period (October 1, 2012 to May 5, 2013), the fourth period (May 6, 2013 to September 30, 2017), and the fifth period (October 1, 2017 to December 31, 2022). We utilized text mining, an unstructured big data analysis method. Keywords were collected and analyzed using Textom, and the frequency analysis of the top 30 keywords, structural features of the semantic network, centrality analysis, QAP correlation analysis, and co-occurrence analysis were conducted. Results: The frequency analysis showed that the top keywords for each time period were 'Cavities', 'Treatment', and 'Children'. In the structural features of the semantic network of pit and fissure sealants by time period, the density index was found to be around 1.00 for all time periods. The QAP correlation analysis showed the highest correlation between the first and second periods and the fourth and fifth periods with a correlation coefficient of 0.834. The co-occurrence analysis showed that 'cavities' and 'prevention were the top two words across all time periods. Conclusion: This study showed that pit and fissure sealants are well accepted by the society as a preventive treatment for caries. However, the awareness of health education related to these sealants was found to be low. Efforts to revitalize stagnant pit and fissure sealants need to be strengthened with effective education.

• Journal of Space Technology and Applications
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• v.4 no.2
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• pp.153-168
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• 2024

Sounding rockets are cost-effective and rapidly deployable tools for directly exploring the ionosphere and microgravity environments. These rockets achieve their target altitudes quickly and are equipped with various scientific instruments to collect real-time data. Perigee Aerospace plans its inaugural test launch in the first half of 2024, followed by a second performance test launch in January 2025. The second launch, scheduled off the coast of Jeju Island, aims to reach an altitude of approximately 150 km with a payload of 30 kg, conducting various experiments in the suborbital region. Particularly in mid-latitude regions, the ionosphere sporadically exhibits increased electron densities in the sporadic E layers and magnetic fluctuations caused by the equatorial electrojet. To measure these phenomena, the sounding rocket version of ionospheric anomaly monitoring by magnetometer and plasma-probe (IAMMAP), currently under development at the KAIST Satellite Research Center, will be onboard. This study focuses on enhancing our understanding of the mid-latitude ionosphere and designing observable missions for the forthcoming performance tests.

• Journal of the Korean GEO-environmental Society
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• v.25 no.8
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• pp.13-19
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• 2024

In this study, to reinforce the surface layer of weathered soil slopes where erosion and collapse of surface layer occur, compression strength tests were conducted by mixing carbon fiber and eco-friendly stabilizer (E.S.B.) To determine the optimal mixing ratio of E.S.B. and carbon fiber, E.S.B. was set at conditions of 10%, 20%, and 30%, and carbon fiber at 0.3%, 0.6%, 0.9%, and 1.2%. Additionally, to analyze the changes in compressive strength according to dry density and curing period, 85% and 95% of the maximum dry unit weight were applied, and curing periods were set to 3 days, 7 days, and 28 days. The standard strength for surface layer reinforcement of slopes is proposed as 4 MPa at 7 days and 6 MPa at 28 days according to ACI 230.1R-09 (2009). The compression test results showed that the unconfined compressive strength of E.S.B. reinforced soil met the standard strength at an E.S.B. mixing ratio of 10% or more for 95% compaction. Moreover, when carbon fiber was mixed with E.S.B. reinforced soil, a ductile fracture pattern was observed after the yield point due to compressive strength, indicating that the mixture could compensate for post-yield failure. It was analyzed that the maximum strength is exhibited at a carbon fiber mixing ratio of 0.6%. The unconfined compressive strength of carbon fiber reinforced soil increases by approximately 54-70% compared to the condition without carbon fiber.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.19 no.4
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• pp.161-182
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• 2024

The study analyzed the rapidly growing food tech startup in South Korea, focusing on industry classification, core technological domains, investment stages, and growth trajectories. Utilizing the ERIS model, two innovative food tech startups, MyChef and CatchTable, were examined as case studies. Results revealed food tech startups are focusing on information technology and smart distribution technology-oriented solutions rather than traditional food production. This study also found that robotics and AI integration were key technology areas. Analyzing the emergence of food tech startups, investment stages, and cumulative investment amounts based on founding years revealed a trend of scaling operations through rounds of funding, especially after securing SERIES A and B funding. The period between 2014 and 2018 saw a dense concentration of food tech startup establishments, likely influenced by favorable conditions for technological innovation amid the Fourth Industrial Revolution. The high rate of strategic mergers and acquisitions and bankruptcy can be interpreted as the complexity inherent in the food tech industry. The case study of MyChef, which grew into HMR manufacturing, and Wad(CatchTable), which expanded into a restaurant reservation platform, derived the entrepreneurs, resources, industry, and strategic factors that served as success factors for food tech startups. This study has practical implications in that it provides entrepreneurs, investors, and policymakers in the food tech industry with insight and direction to develop strategies in line with market trends and technological changes and promote sustainable growth.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.50 no.3
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• pp.201-211
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• 2024

The aim of this study was to propose Rosa multiflora (R. multiflora) as a cosmetic material for refining pores, and the ethanolic extract of R. multiflora (RME) was used to identify changes in various factors related to sebum regulation, astringency, and extracellular matrix, which are known to affect pores, and the effects were confirmed through clinical trials. The effects of these changes were confirmed through clinical trials. As a result, RME suppresses the excessive production of sebum, and it possesses DPPH radical scavenging ability through an astringent tannin component. Futhermore, RME inhibited 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) activity and matrix metalloproteinase-1 (MMP-1) production, and it increased hyaluronic acid synthesis. In clinical trials, it was confirmed that RME significantly reduced the area, depth, number, volume, and density of pores-key parameters for assessing pores-and it also reduced sebum levels. This suggests that RME has an astringent effect and could be used as a cosmetic ingredient to improve the appearance of pores by controlling sebum production and influencing ECM-related factors.

• Clinical and Experimental Pediatrics
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• v.50 no.11
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• pp.1091-1096
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• 2007

Purpose : The of common carotid artery intima media thickness (IMT) is an acknowledged noninvasive marker for early atherosclerotic changes. We investigate whether common carotid IMT is different between obese and normal-weight children and also evaluate the relationships IMT with cardiovascular risk factors. Methods : We collected the clinical data (age, sex, pubertal stage, body mass index) and measured blood pressure, glucose, insulin, lipid profiles and adiponectin in 49 obese children (mean age, 12 years) and 24 nonobese children as controls. The control group was composed of 24 nonobese children of the same age, sex and pubertal stage. We measured the carotid IMT of all subjects by B-mode ultrasound with a 7.5-MHz linear transducer and analyzed. Results : Obese children demonstrated a significantly thicker intima media (mean, 0.34 mm, peak, 0.42 mm) compared to the control group (mean, 0.31 mm, peak, 0.38 mm, P<0.01). IMT was significantly correlated to the BMI (r=0.431, P<0.01), age (r=0.317, P<0.01), total cholesterol (r=0.377, P< 0.01), triglyceride (r=0.253, P<0.05) and low-density lipoprotein cholesterol (r=0.289, P<0.05). Serum adiponectin was significantly lower in obese children than in controls (11.2 ng/mL vs. 14.7 ng/mL, P<0.05) and negatively related with IMT (r=-0.267, P<0.05). Conclusion : Obesity is associated with increased carotid artery IMT in children. Our results suggest vascular changes in obesity seem to occur already in childhood and vascular ultrasonography may helpful for screening cardiovascular complications in obese children.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.3
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• pp.332-338
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• 2012

Soil compaction is one of the major problems facing modern agriculture. Overuse of machinery, intensive cropping, short crop rotations, intensive grazing and inappropriate soil management leads to compaction. This study was carried out evaluate of the effects soil texture and different compaction levels within the soil profile on the soybean root growth and productivity. The soybean plants were grown in $21cm{\o}{\times}30cm$ cylinder pots using three different soil textures (clay, fine loamy and coarse loamy) compacted at different compaction levels (1.25, 1.50, 1.75, and 2.00 MPa). Results revealed that soybean development is more sensitive on penetration resistance, irrespective of soil type. Soybean yield and root weight density significantly decreases with increasing levels of soil compaction in both clayey and fine loamy soils, but not in coarse loamy soil. The highest root weight density was recorded in coarse loamy soils, followed by fine loamy and clay soils, in descending order. The root growth by soil compaction levels started to decline from 1.16, 1.28 and 1.60 MPa for clay, fine loamy and coarse loamy soils. Soybean production in the field experiment decreased about 30% at compacted sub-soils compared to undisturbed soils.

• Economic and Environmental Geology
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• v.47 no.4
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• pp.441-453
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• 2014

Thermal and physical properties were measured on 206 Jurassic granite samples obtained from three boreholes in the central part of Korea. Thermal conductivity(${\lambda}$), thermal diffusivity(${\alpha}$), and specific heat(Cp) were measured in a laboratory; the average values are ${\lambda}$=2.813 W/mK, ${\alpha}=1.296mm^2/sec$, and Cp=0.816 J/gK, respectively. In addition, porosity(${\phi}$), and dry and saturated density(${\rho}$) were measured in the laboratory; the average values are ${\phi}$=0.01, ${\rho}(dry)=2.662g/cm^3$ and ${\rho}(saturated)=2.67g/cm^3$, respectively. Thermal diffusivity of 10 granite samples were measured with increasing temperature from $25^{\circ}C$ to $200^{\circ}C$. In this study, we found that thermal diffusivity at $200^{\circ}C$ is about 30% lower than thermal diffusivity at $25^{\circ}C$. In correlation analysis, thermal conductivity increases with increasing thermal diffusivity. However, thermal conductivity does not show good correlation with porosity and density. Consequently, we know that thermal conductivity of granite would be more influenced by mineral composition than by porosity. We also derived ${\rho}=-2.393{\times}{\phi}+2.705$ from density and porosity data. XRD and XRF analysis were performed to investigate effects of mineral and chemical composition on thermal conductivity. From those results, we found that thermal conductivity increases with increasing quartz and $SiO_2$, and decreases with increasing albite and $Al_2O_3$. Regression analysis using those mineral and chemical composition were carried out ; we found $K=0.0294V_{Quartz}+1.93$ for quartz, $K=0.237W_{SiO_2}-14.09$ for $SiO_2$, and $K=0.053W_{SiO_2}-0.476W_{Al_2O_3}+6.52$ for $SiO_2$ and $Al_2O_3$. Specific gravities were measured on 10 granite samples in the laboratory. The measured specific gravity depends on chemical compositions of granite. Therefore, specific gravity can be estimated by the felsic-mafic index(F) that is calculated from chemical composition. The estimated specific gravity ranges from 2.643 to 2.658. The average relative error between measured and estimated specific gravities is 0.677%.

• Journal of agricultural medicine and community health
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• v.38 no.3
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• pp.163-173
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• 2013

Objectives: There has been an increase in the use of mind-body therapies to control cardiovascular risk factors recently. This trial was designed to determine whether the 'jeol'(Korean Buddhists' prostration) meditation program, as a new mind-body intervention, was effective in managing stress, depression and controlling cardiovascular risk factors in women working at a geriatric hospital. Methods: We conducted a randomized controlled trial to determine whether the 'jeol' meditation program could improve stress, anxiety, depression, and cardiovascular risk factors in women. We randomly assigned 57 participants to the intervention(29 participants) or control(28 participants) group. The subjects in the intervention group participated in a group Jeol meditation program once weekly, and practiced at home. The following variables were assessed: stress(Psychosocial Wellbeing Index), depression(Beck's Depression Inventory), body mass index(BMI), waist circumference, hemoglobin A1c(HbA1c), homeostasis model assessment(HOMA), low-density lipoprotein(LDL) cholesterol, high-density lipoprotein(HDL) cholesterol, and triglyceride were assessed. Results: After the 8-week program, 2 participants from the intervention group and 1 from the control group dropped out. The subjects in the intervention group exhibited decreased scores for stress(t=5.102, p<0.01), depression(t=5.259, p<0.01), BMI(t=2.942, p=0.007), and waist circumference(t=2.582, p=0.016); however these scores did not demonstrate a significant decrease in participants of the control group. The other variables showed no significant difference between the groups. Conclusion: The 'jeol' meditation program evidently reduced stress, anxiety, depression, body weight, and waist circumference in women, which suggests that this program could be employed as a mind-body therapies.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.4
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• pp.424-429
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• 2012

This study was carried out to investigate the influence of different planting time on the synthesis of isoflavone in black soybean, Three varieties used in this experiment were lpumgeomjeongkong, Cheongjakong and Heugcheongkong which had different ecotypes, repectively. Seeds were sown at different time, May 15th, May 30th and June 15th with planting density of $60{\times}15cm$. In order to analyze the content of isoflavone, we collected sample every 5 days from 30 days after flowering to harvest and analyzed them with UPLC. As sowing was delayed, the content of isoflavone increased in all of three varieties. The content of genistein was greater than daidzein and glycitein. Increase of Glycitein was not distinct from 55 days after flowering(DAF) and it was stable against temperature change during the seed developing period. Although the content of genistein in Ilpumgeomjeongkong from 50 to 55 DAF, in Cheongjakong from 40 to 55 DAF and in Heugcheongkong from 60 to 65 DAF was lower than the content of daidzein, it was higher than that of daidzein afterward. In the statistical analysis on the relationship between average temperature and the content of aglycone isoflavone at 5-day intervals from 30 DAF during the grain filling period, genistein in Ilpumgeomjeongkong showed meaningful correlation as y=-15.28x+407.9 ($R^2=0.505^*$), diadzein in Cheongjakong showed meaningful correlation as y=-6.188x-164.5($R^2=0.454^*$), and genistein showed significantly high correlation as y=-11.59x+297.6 ($R^2=0.545^{**}$). Taking all the above results into consideration, it was suggested that the regions suitable for high content of isoflavone in black soybean be the northern area of Gyeonggi-do and Gangwon-do, Chungcheongbuk-do and inland area of Gyeongsangbuk-do, where are relatively low average temperature from flowering stage($R_2$) during the grain filling period.