• Journal of the Korea Convergence Society
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• v.12 no.11
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• pp.127-134
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• 2021

This study was to analyze the convergence factors of influencing subjective happiness of oral health characteristics in adolescents. The data were analyzed using the 16th(2020) Korea Youth Risk Behavior Survey(n=54,948), logistic regression analysis was conduct. Subjective happiness were significantly different means by general characteristics(gender, grade, school record, economic status, residence type, suicidal ideation, drinking, smoking, mother's education) and oral health characteristics(number of toothbrushes, toothbrushing after lunch, experience of tooth break, pain and gingiva bleeding). Convergence factors affecting oral health characteristics on subjective happiness were number of toothbrushes(2times(OR=1.45), 3times(OR=1.53)), tooth brushing after lunch(OR=1.19), experience of sealant(OR=1.08), tooth pain(OR=0.73) and gingiva bleeding(OR=0.74). This study will be used as a basics data on the improvement of the subjective happiness in adolescents.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.369-372
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• 2021

These days, people spend more time sitting at a desk for studies or work. Also, because people continue to use computers, smartphones, and tablet PCs often during break times, their posture is getting worse. Maintaining a position of bad posture for an extended period of time causes problems with the musculoskeletal system related to the neck, shoulders, and spine. Additionally, problems such as physical fatigue and posture deformation are predicted to expand to a wide range of age groups. Therefore, the core function of the system we are developing is to ensure correct sitting posture and to receive alert notifications via the created mobile application. To create the system, a flex sensor, pressure sensor, and tilt sensor are attached to a chair and utilized. The flex sensor detects and compares the amount of bending in the chair's posture and transmits this value to an Arduino Uno R3 board. Additionally, information such as body balance and incline angle are collected to determine whether or not the current sitting posture is correct. When the posture is incorrect, a notification is sent through the mobile application to indicate to the user and the monitoring app that their posture is not correct. The system proposed in this study is expected to be of great help in future posture-related research.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.3
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• pp.177-183
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• 2023

Various failure modes occur in the concrete beams reinforced with GFRP(Glass Fiber Reinforced Plastic) under initial condition and repairing patterns. In this study, the failure behaviors of concrete beams restrengthened with GFRP sheet with slightly higher elastic modulus than concrete were investigated. For the tests, concrete beams with 24 MPa were manufactured, and the effects of initial notch, overlapping, end-strip reinforcement, and fiber anchors were analyzed on failure load. The cases of GFRP overlap around notch and the initial notch showed increasing failure loads similar to those of normal restrengthened case since the epoxy of the saturated GFRP sufficiently repaired the notch area. Compared to the control case without restrengthening of GFRP, the concrete with initial notch showed 0.78 of loading ratio and normal restrengthening showed 4.43~5.61 times of increasing ratio of failure loading, where interface-debonding from flexural crack were mainly observed. The most ideal failure behavior, break of GFRP, was observed when end-strip over 1/3 height from bottom and fiber anchor were installed, which showed increasing failure load over 150 % to normal restrengthening.

• Journal of Microbiology and Biotechnology
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• v.33 no.9
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• pp.1228-1237
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• 2023

The CRISPR-Cas system has emerged as the most efficient genome editing technique for a wide range of cells. Delivery of the Cas9-sgRNA ribonucleoprotein complex (Cas9 RNP) has gained popularity. The objective of this study was to develop a quantitative polymerase chain reaction (qPCR)-based assay to quantify the double-strand break reaction mediated by Cas9 RNP. To accomplish this, the dextransucrase gene (dsr) from Leuconostoc citreum was selected as the target DNA. The Cas9 protein was produced using recombinant Escherichia coli BL21, and two sgRNAs were synthesized through in vitro transcription to facilitate binding with the dsr gene. Under optimized in vitro conditions, the 2.6 kb dsr DNA was specifically cleaved into 1.1 and 1.5 kb fragments by both Cas9-sgRNA365 and Cas9-sgRNA433. By monitoring changes in dsr concentration using qPCR, the endonuclease activities of the two Cas9 RNPs were measured, and their efficiencies were compared. Specifically, the specific activities of dsr365RNP and dsr433RNP were 28.74 and 34.48 (unit/㎍ RNP), respectively. The versatility of this method was also verified using different target genes, uracil phosphoribosyl transferase (upp) gene, of Bifidobacterium bifidum and specific sgRNAs. The assay method was also utilized to determine the impact of high electrical field on Cas9 RNP activity during an efficient electroporation process. Overall, the results demonstrated that the qPCR-based method is an effective tool for measuring the endonuclease activity of Cas9 RNP.

• Journal of Electrochemical Science and Technology
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• v.15 no.2
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• pp.291-298
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• 2024

Due to its high theoretical capacity, Silicon (Si) has shown great potential as an anode material for lithium-ion batteries (LIBs). However, the large volume change of Si during cycling leads to poor cycling stability and low Coulombic efficiency. In this study, we synthesized Si/Carbon C45:Graphene composites using a ball-milling method with a fixed Si content (20%) and investigated the influence of the C45/Gr ratio on the electrochemical performance of the composites. The results showed that carbon C45 networks can provide good conductivity, but tend to break at Si locations, resulting in poor conductivity. However, the addition of graphene helps to reconnect the broken C45 networks, improving the conductivity of the composite. Moreover, the C45 can also act as a protective coating around Si particles, reducing the volume expansion of Si during charging/discharging cycles. The Si/C45:Gr (70:10 wt%) composite exhibits improved electrochemical performance with high capacity (~1660 mAh g^-1 at 0.1 C) and cycling stability (~1370 mAh g^-1 after 100 cycles). This work highlights the effective role of carbon C45 and graphene in Si/C composites for enhancing the performance of Si-based anode materials for LIBs.

• Korean Journal of Radiology
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• v.2 no.2
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• pp.75-79
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• 2001

Objective: To evaluate the biodurability of the covering material in retrievable metallic stents covered with polycarbonate polyurethane. Materials and Methods: Using a peristaltic pump at a constant rate of 1ml/min, bile was recirculated from a reservoir through a long tube containing four stents. Each of these was removed from the system every two weeks and a radial tensile strength test and scanning electron microscopy (SEM) were performed. Each stent, removed at 2, 4, 6 and 8 weeks, was compared with a control stent not exposed to bile juice. Results: Gross examination showed that stents were intact at 2 weeks, but at 4, 6 and 8 weeks cracks were observed. The size of these increased gradually in accordance with the duration of exposure, and at 8 weeks several large holes in the polyurethane membrane were evident. With regard to radial tensile strength, extension and peak load at break were 84.47% and 10.030 N/mm, 54.90% and 6.769 N/mm, 16.55% and 2.452 N/mm, 11.21% and 1.373 N/mm at 0, 2, 4 and 6 weeks, respectively. Scanning electron microscopy at 2 weeks revealed intermittent pitting and cracking, and examination at 4, 6 and 8 weeks showed that the size of these defects was gradually increasing. Conclusion: When the polyurethane membrane was exposed to bile, biodegradation was first observed at week two and increased gradually according to the duration of exposure.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.429-439
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• 2013

Purpose: This study was assessed to investigate the change of subjective and/or objective symptoms and the light transmissibility of lens caused by over-usage of daily disposable circle contact lenses (circle lens). Methods: Three daily disposable circle lenses made of etafilcon A, hilafilcon B, and nelfilcon A were applied on 20 normal eyes free from any eye diseases by when subjects complained any kind of discomfort. On the first and the last days of lens wearing, subjective discomfort, blinking rate, non-invasive break-up time, lens centration on corneal surface and visible light transmissibility of lens were recorded at every case and compared. Results: The circle lens wearers complained discomfort when they wore the circle lens more than 15 hours, in excess of 8 hours being the recommended wearing time and the most circle lens wearers quit the lens wearing when they wore more than 30 hours. On the last day of lens wearing, the representative subjective discomforts were stiffness, dryness and tiredness. When the subjects wore circle lens more than the recommended time, a tendency of increased blinking rate and decreased NIBUT was observed when it compared with the values right after lens wearing. On the last day of lens wearing, the lens centration was shown to be decentrated from the pupil center compared with the centration right after the wearing. These changes in lens centration and blinking rate were consistently shown in all cases of lens wearing however, the difference in the degree of subjective and/or objective change was present depending on lens materials and subjects. The visible light transmissibility of circle lens has largely been changed. Conclusions: From these results, it was thought that the decreased NIBUT induced dryness and stiffness and decreased visible light transmissibility caused more blinking when daily disposable circle lens was exceedingly used, which provoked lens decentration and subjective discomfort. However, the difference of subjective and/or objective change was largely varied in accordance with the lens material types and individuality and thus it may occur some unexpected problems by the individual base. Therefore, the education about the necessity to comply with the recommended wearing time and the problem will be essential.

• The Korean Journal of Coaching Psychology
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• v.8 no.1
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• pp.1-50
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• 2024

The purpose of this study is to identify career barrier factors experienced by career interruption women, develop a tool to measure career barrier, and verify their validity. To this end, preliminary questions were developed by reviewing literature, conducting one-on-one in-depth interviews with 10 women on career interruption, and conducting an open questionnaire with 100 women on career interruption. The subjects of the study were married women aged 20 to 54 who had past employment experience, wanted to be re-employed, and experienced retirement due to marriage, pregnancy, childbirth, childcare, and family care, and the period of career interruption was selected for more than one year. After that, 63 questions were selected for 7 factors. A preliminary survey was conducted on 300 women with career interruption in Korea, and as a result, 63 questions of 6 factors were derived through exploratory factor analysis. The main survey was conducted with 44 questions of 6 factors by partially modifying the questions reflecting the important concepts in each factor. In this survey of 600 people, in order to verify the validity of the constituent concept of this test, the entire sample was divided into two groups, and group 1 (G1, N=309) conducted exploratory factor analysis and group 2 (G2, N=291) conducted confirmatory factor analysis. As a result of exploratory factor analysis for Group 1, 34 questions of 6 factors were finally derived, and a confirmatory factor analysis of Group 2(G2) was conducted to confirm the model fit of the derived factors, and it was confirmed that the model fit criteria were met. In order to verify the convergence validity of the developed career barrier scale, a correlation analysis was conducted with the career barrier test for female college students, and as a result of the analysis, the career barrier scale for women with career interruption and the career barrier test for female college students showed statistically significant correlation. In order to verify the validity of the criterion, the results of a correlation analysis with variables of job preparation behavior, job stress, state anxiety, and life satisfaction were all found to be statistically significant. Finally, the academic, practical, and policy significance and limitations of this study and future research directions were presented.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.5
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• pp.625-632
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• 2008

Rye-wheat mixed bread samples made with substitutions of 20, 40, 60 and 80% sourdough, and control made with the addition of naturally fermented raisin extract, were examined for quality characteristics such as pH, total titratable acidity, fermentation power of dough expansion, specific volume, baking loss, water activity, color, texture, external and internal surface appearance, and sensory qualities, in order to determine the optimal ratio of sourdough in the formulation. As the incubation time of sourdough increased, pH decreased, while total titratable acidity increased. The pH of rye-wheat mixed doughs decreased with increasing sourdough content, but total titratable acidity increased. The rye-wheat mixed breads prepared with substitutions of sourdough had higher pH and lower total titratable acidity than the control group. Fermentation power of dough expansion of rye-wheat mixed doughs increased with increasing incubation time. Specific volume was maximum on the 20% substitution sourdough. Baking loss was inferior with the 80% substitution sourdough. Water activity and lightness was minimum on the control group. The higher amounts of sourdough showed the higher tendency of lightness, redness and yellowness. In the texture characteristics, hardness, gumminess, and chewiness was minimum on the control group and tended to increase with higher substitution of sourdough. Substitution of sourdough showed decrease adhesiveness. Fracturability, cohesiveness, and resilience of all rye-wheat mixed breads were not significantly different. Springiness was maximum on the 20% substitution sourdough and minimum on the 40%. A side of loaf of rye-wheat mixed breads, except for 20%, had a poor break and shred. In sensory evaluation, as substitution amount of sourdough increased, the scores of color and consistency of crumb, uniformity of crumb pore, gumminess, and overall acceptability decreased; while the density of crumb pore, springiness of crumb, aroma of rye flour, sourness, and bitterness showed the reverse effect; the 20, 40, and 60% sourdough samples obtained fairly good scores. In conclusion, these results indicated that $20{\sim}60%$ of sourdough could be very useful as a substitute for baker's yeast in developing rye-wheat mixed bread.

• Journal of Korean Ophthalmic Optics Society
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• v.21 no.3
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• pp.191-201
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• 2016

Purpose: In the present study, the effect of artificial tears with different ingredients on tear film stability and subjective symptoms of dry eyes in the early stage of soft contact lenses wear was investigated. Methods: The three kinds of artificial tears and saline solution were respectively applied onto 50 dry eyes which wore soft contact lenses made of etafilcon A. Then, non-invasive tear film break-up time (NIBUT) was measured at every five minutes for 30 minutes right after the instillation of artificial tears, and the changes in blink rate and subjective symptoms were estimated after 30 minutes from the instillations. Results: All three kinds of artificial tears increased NIBUT larger than saline. The effect of increasing NIBUT immediately after the instillation of artificial tears was the largest when the artificial tear containing viscosity enhancer was used. The duration time of the effect was the longest when the artificial tear having both surfactant and viscosity enhancer was applied. The blink rate was not significantly changed when both artificial tears and saline solution were instilled. Subjective symptoms were significantly improved by the instillation of both artificial tears and saline solution and dryness, irritation, tiredness, stiffness, dazzling were improved by the use of most solutions. However, the subjective symptoms were rebounded to the level before the instillation of artificial tears after 30 minute-instillation. Conclusions: It was revealed that both artificial tears and saline solution could improve the subjective symptoms of dry eye in the early stage of soft contac lenses however, the effect of these solutions on the tear film stability was different according to the components. From the results, it is suggested that the proper selection of artificial tears is necessary for the improvement of dry eye symptoms at the early stage of soft contact lenses wear in dry eye.