• The Journal of Korean Academy of Prosthodontics
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• v.60 no.1
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• pp.71-79
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• 2022

Excessive crown height space increases can cause crestal bone loss and screw loosening after prosthesis is placed. Milled bar and implant overdenture can be used as a treatment method for partially edentulous patients who have severe alveolar bone loss and excessive crown height space. Milled bar can provide primary splinting effect and stability between implants. Also, milled bar with additional retention device such as Advanced Dental Device-Treatment Of Choice (ADD-TOC) and magnet can provide additional retention force for implant overdenture. In this case, the patient has a partially edentulous mandible that has severe alveolar bone loss and multiple number of teeth loss after excision due to leiomyosarcoma. Because of the long-term loss of mandibular molars, the opposing teeth were extruded. Maxillary left molars were corrected to the occlusal plane through molar intrusion, and mandibular left molar region were treated with implant overdenture, using milled bar with ADD-TOC and magnet after implant placement. The clinical result was satisfactory on the aspect of esthetic and masticatory function.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.4
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• pp.313-319
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• 2022

Complete dentures are one of the most basic treatment methods for the treatment of edentulous patients. The manufacturing process of traditional complete dentures goes through the steps of taking primary impressions, secondary impressions, jaw relation record, trying in wax denture, and final denture insertion. Multiple visits and complex manufacturing procedures are required, and errors may occur in each step. With the development of digital technology, manufacturing steps have been reduced by introducing digital technology to the denture treatment process. In the process of manufacturing dentures by introducing a digital process, a more precise work is possible using Computer-Aided Design, and it is possible to shorten the period of labor and reduce the number of visits. In this case, the anterior teeth arrangement of the patient's existing dentures was transferred to the final dentures using a digital method. After taking impression, try-in dentures were digitally fabricated and tried in the oral cavity to evaluate their retention in the oral cavity. Final dentures were manufactured by milling process. The number of visits was reduced, satisfactory retention and stability of dentures were obtained, and aesthetic recovery was achieved.

• Journal of the Korean Geotechnical Society
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• v.38 no.11
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• pp.107-118
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• 2022

The social need for stable hydrogen storage technologies that respond to the increasing demand for hydrogen energy is increasing. Among them, underground hydrogen storage is recognized as the most economical and reasonable storage method because of its vast hydrogen storage capacity. In Korea, low-depth hydrogen storage using artificial protective structures is being considered. Further, establishing corresponding safety standards and ground stability evaluation is becoming essential. This study evaluated the hydro-mechanical behavior of the ground during a hydrogen gas leak from a low-depth underground hydrogen storage facility through the HM coupled analysis model. The predictive reliability of the simulation model was verified through benchmark experiments. A parameter study was performed using a metamodel to analyze the sensitivity of factors affecting the surface uplift caused by the upward infiltration of high-pressure hydrogen gas. Accordingly, it was confirmed that the elastic modulus of the ground was the largest. The simulation results are considered to be valuable primary data for evaluating the complex analysis of hydrogen gas explosions as well as hydrogen gas leaks in the future.

• Journal of Korean Home Economics Education Association
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• v.35 no.2
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• pp.111-132
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• 2023

The objective of this research is to conceptualize care competences for adolescents and to develop a valid measurement tool based on this conceptualization. The primary aim is to establish a solid foundation for effective communication in teaching care competences within the domain of home economics education. To achieve this, a comprehensive review of relevant literature and previous studies was conducted, and consultations with experts were undertaken to assess content and criterion-related validity. Furthermore, exploratory and confirmatory factor analyses were performed. The findings from these analyses resulted in a set of 34 items, which were categorized into five distinctive factors representing care competences in adolescents. These factors encompassed four items of care thinking, seven items of care emotion, six items of care behavior, seven items of self-care and ten items of community-care. Additionally, a reliability analysis was performed on the model, confirming the stability and consistency of the five factor structure and the 34 item scale, which assess care competences in adolescents.

• Korean Journal of Culture and Social Issue
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• v.14 no.1_spc
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• pp.299-317
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• 2008

The school drop-out among the youth has grown to become a serious social problem since about 2000 and calls for an attention to its seriousness. Therefore, this study reviewed the statitistical reports and the previous empirical findings on the school drop-out and integrated to establish a comprehensive understanding of this social phenomenon. The main concepts and terminologies on school drop-out, the current statistics, the possible causal factors and the usual trajectory the youth take after dropping-out of school were discussed to conceptualize the issue. Analyses indicated 12 characteristics of the students who dropped out of school. Those 12 characteristics were restructured according to the ecological conceptual model. The social instability and the financial crisis in the 1990's has eroded the stability of the primary environments of adolescents such as family and school. The family breakdowns from divorce and other reasons weakened psychological and financial support for adolescents. The diminished authority of teachers and school over students exposed conflicts between teacher and students, students' loss of purpose and interest in academic attainment. The adolescents showed emotional reponses like increased level of depression, helplessness, aggression, indicated cognitive reponses such as the loss of purpose and interest in studying, a heightened sense of uncertainty of the future, and behavioral responses like sexual acting out behaviors, and bullying. The unmet psychological needs of adolescents result in run-away and school drop-out behaviors, which in turn progress into juvenile delinquency as the society fails to provide adequate and appropriate guidance and interventions. The intervention strategies at the national level were proposed and the limitations of the study were discussed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.6
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• pp.709-719
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• 2023

In general, most of the electrical equipment responsible for control within power plants is housed in self-standing cabinets. These cabinets are typically fixed to a slab using post-installed anchors. Although the fixation method of using post-installed anchors provides stability, there is a risk of conductor failure due to external forces, including moments. However, the performance assessment of current anchors is only evaluated through uniaxial material tests. Therefore, the primary purpose of this study is to compare the static performance of post-installed anchors, considering on-site installation conditions, with their performance in material tests and to analyze the behavioral characteristics of the anchors. While conducting experiments using actual cabinets would be ideal, practical and spatial constraints make this approach difficult. As an alternative, experiments were conducted using a test specimen consisting of a steel column and a support. As a result, the pull-out performance of anchors reflecting on-site installation conditions was measured to be about 10% higher than that observed in material tests. The trends in load reduction and the point of maximum performance for the anchors also differed. To verify the reliability of the experimental study, a 3D FEM analysis was performed, which will provide predictive information on the loads transferred to the post-installed anchors for structural performance evaluations of electrical cabinets using shaking table test in the future.

• Korean Journal of Radiology
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• v.23 no.11
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• pp.1067-1077
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• 2022

Objective: To determine whether Sonazoid-enhanced ultrasound (SZUS) was noninferior to SonoVue-enhanced ultrasound (SVUS) in diagnosing hepatocellular carcinoma (HCC) using the same diagnostic criteria. Materials and Methods: This prospective, single-center, noninferiority study (NCT04847726) enrolled 105 at-risk participants (71 male; mean age ± standard deviation, 63 ± 11 years; range, 26-86 years) with treatment-naïve solid hepatic nodules (≥ 1 cm). All participants underwent same-day SZUS (experimental method) and SVUS (control method) for one representative nodule per participant. Images were interpreted by three readers (the operator and two independent readers). All malignancies were diagnosed histopathologically, while the benignity of other lesions was confirmed by follow-up stability or pathology. The primary endpoint was per-lesion diagnostic accuracy for HCC pooled across three readers using the conventional contrast-enhanced ultrasound diagnostic criteria, including arterial phase hyperenhancement followed by mild (assessed within 2 minutes after contrast injection) and late (≥ 60 seconds with a delay of 5 minutes) washout. The noninferiority delta was -10%p. Furthermore, different time delays were compared as washout criteria in SZUS, including delays of 2, 5, and > 10 minutes. Results: A total of 105 lesions (HCCs [n = 61], non-HCC malignancies [n = 19], and benign [n = 25]) were evaluated. Using the 5-minutes washout criterion, per-lesion accuracy of SZUS pooled across the three readers (72.4%; 95% confidence interval [CI], 64.1%-79.3%) was noninferior to that of SVUS (71.4%; 95% CI, 63.1%-78.6%), meeting the statistical criterion for non-inferiority (difference of 0.95%p; 95% CI, -3.8%p-5.7%p). The arterial phase hyperenhancement combined with the 5-minutes washout criterion showed the same sensitivity as that of the > 10-minutes criterion (59.0% vs. 59.0%, p = 0.989), and the specificities were not significantly different (90.9% vs. 86.4%, p = 0.072). Conclusion: SZUS was noninferior to SVUS for diagnosing HCC in at-risk patients using the same diagnostic criteria. No significant improvement in HCC diagnosis was observed by extending the washout time delay from 5 to 10 minutes.

• Journal of Life Science
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• v.34 no.9
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• pp.647-655
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• 2024

The synthesis of cerium oxide nanoparticles (nanoceria, CeO₂) has received significant attention across scientific and technological disciplines in the last decade. This article explores an overview of the green synthesis method and the antibacterial activity of nanoceria. The utilization of biological materials, such as plants and microorganisms, in the synthesis of nanoceria, has gained attention as an ecofriendly approach. Plants are rich in phytochemicals, including alkaloids, flavonoids, phenols, proteins, and other nutritious components. Likewise, microorganisms generate bioactive metabolites, pigments, enzymes, proteins, acids, and antibiotics. The phytochemicals and metabolites are involved in the reduction of metal salt into nanoceria and provide stability to synthesized nanoparticles. Nanoceria synthesis using plants and microorganisms is facile and ecofriendly, and synthesized nanoceria are biocompatible. Many biomedical applications of nanoceria have been reported, including those that are anticancer, anti-inflammatory, larvicidal, enzyme inhibiting, antibiofilm, and antimicrobial. However, in this review, we focused on and described in detail the antibacterial potential of nanoceria. The antibacterial activity of nanoceria occurs due to excessive reactive oxygen species generation, the impairment of the cell membrane, and the inhibition of cellular mechanisms. Ultimately, this review's primary goal is to provide readers with a logical understanding of the significant achievements of nanoceria as a cutting-edge therapeutic agent for treating a range of microbial pathogens and combating other diseases.

• Journal of Korean Home Economics Education Association
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• v.36 no.2
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• pp.15-31
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• 2024

This study employs photovoice research methodology to investigate adolescents' experiences in sibling relationships and to analyze the impact of sibling interactions on their development and growth. The participants comprised eight high school students with one sibling (four males and four females) residing in the Incheon region. The research process encompassed several stages: participant recruitment, orientation, photovoice activity (focus group interviews), data analysis, and conclusion derivation. During the photovoice activity, participants engaged in a narrative process of photographing, interpreting, and discussing their experiences. The narratives were categorized into four primary themes: structure and environment, emotional interactions, roles, and parental subsystems. The conclusions drawn from the study are as follows: First, the similarity formed in sibling relationships during adolescence contributes to psychological stability. Second, roles and expectations based on birth order can cause stress for adolescents, indicating the need for equitable role adjustments within the family. Third, conflict in sibling relationships is crucial for enhancing problem-solving and social relationship skills. Lastly, consistent parenting attitudes significantly affect the emotional well-being of siblings. This study emphasizes the significance of fostering a deeper understanding of human development and family relationships through an exploration of adolescent sibling dynamics within home economics education.

• Journal of the Korea Institute of Building Construction
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• v.24 no.5
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• pp.565-575
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• 2024

This research was initiated to establish quality standards and testing methods for fine dust in aggregates, a component currently not regulated under the Korean Industrial Standards(KS) KS F 2527 for Concrete Aggregates. With limited existing research and no definitive quality or testing standards for fine dust, this study sought to provide a quantitative analysis of fine dust in aggregates and to set forth quality standards based on the dust content through a concrete performance evaluation. The experimental findings showed that the primary chemical constituents of the fine dust were aluminum oxide(Al₂O₃), iron oxide(Fe₂O₃), and silicon dioxide(SiO₂). It was observed that increasing levels of fine dust in the aggregates led to higher values of the fine dust index(Al₂O₃+Fe₂O₃). This escalation in the fine dust index corresponded with an increase in the unit water content of the concrete and a consequent decline in compressive strength. Based on these observations, a maximum allowable limit for the fine dust index in aggregates was proposed at 23%. This limit was derived from the correlation between fine dust content and a 15% reduction in compressive strength of standard concrete specimens. The proposed evaluation method for the fine dust index based on its content in aggregates is expected to enhance concrete performance and ensure structural stability. This contribution to the field addresses a significant gap in the standards and provides a foundation for further research and standardization in the construction materials industry.