• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.2
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• pp.193-200
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• 2010

Due to the characteristic of culvert structure, the standard section of the culvert has been established and applied in field. However, this becomes a limitation in selecting a section design corresponding to various field conditions although it can improve the design and applicability of culvert structure. In order to overcome this limitation, we have developed the design and application technology of culvert structure corresponding to the field conditions that various shapes of culvert structure can be covered by assembly of precast segments. Because the structural characteristics of assembling-type waterway culvert structure, the thickness of structure and amount of reinforcing rods can vary according to the fixation or internal hinge status in the connection part of precast segments. This has a strong influence on the applicability and economic efficiency of culvert structure. Accordingly, in order to suggest a reasonable modeling technique of segment connection parts, this study has conducted the field experiment and numerical analysis. According to the results of field experiment and numerical analysis, the slab, wall and base slab with mortar splice sleeves have shown that the assembling-type of waterway culvert structure behaves like an integrated structure.

• Journal of the Korean earth science society
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• v.44 no.3
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• pp.210-221
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• 2023

The purpose of this study is to evaluate the content knowledge and problem solving process used by pre-service earth science teachers while discriminating faults on geological maps. For this, we collected and evaluated data on fixation duration and gaze plot, while pre-service earth science teachers (N=12) solved the problem on faults interpretation using an eye tracker (Tobii Pro Glass 2 model). The results were as follows. First, most of the pre-service earth science teachers know the concepts of the normal and reverse fault but they do not know the procedural knowledge essential for fault interpretation on geological maps. Second, the pre-service earth science teachers did not draw a geological cross-sectional map to interpret the fault on the geological map and interpreted the fault based on two-dimensional information collected from the geological map rather than three-dimensional information. Therefore, it is essential to improve the teaching and learning environment so that pre-service earth science teachers who will become earth science teachers in the future can learn procedural knowledge essential to comprehend natural phenomena including understanding natural phenomena. The results of this study can substantially help organize a new earth science curriculum or develop materials on teachers' education in the future.

• The Journal of the Convergence on Culture Technology
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• v.9 no.4
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• pp.587-592
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• 2023

Plant growth is regulated by a variety of factors, including organic matter availability. Organic nutrients are carbohydrate molecules from photosynthetic products produced by tissues associated with carbon and energy fixation called "sources". These compounds flow through plant vascular bundles into non-photosynthetic or growing tissues called "sinks". Among these possible compounds, the disaccharide fructosyl glucose, sucrose, is the most representative. During the transport of sucrose, the pathway from the source to the sinks can include hydrolysis of sucrose into glucose and fructose derivatives or direct transfer of sucrose. Among the enzymes involved in this, β-D-fructofuranosidase is the most important. Soluble neutral β-D-fructofuranosidase, one of several isoenzymes, is located in intracellular protoplasts and helps plant cells metabolize sucrose to produce energy. In order to track the activity of this enzyme during the course of plant growth, histological methods were used for the most effective immunolocalization. As a result, the activity was higher in the phloem and epidermis than in the mesophyll tissue in the leaf. In the growing stem, activity was high in the phloem, epidermis, and cortex. The activity of the root, which is a sink tissue, was high in all parts, but especially the highest in the root tip part. It is thought that this is because it helps unloading of sucrose in sink tissues that require sucrose degradation and plays a role in hydrolysising sucrose.

• The Korean Journal of Zoology
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• v.22 no.3
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• pp.103-114
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• 1979

The authors observed the ultrastructure of the granular glands in the amphibian skin with an electron microscope. The specimens from the experimental animals (Bombina orientalis, Bufo bufo gargarizans, Rana nigromaculata and Rana rugosa) were fixed in 2.5% glutaraldehyde-paraformaldehyde fixative in phosphate buffer at pH 7.2 prior to fixation in 1% osmium tetroxide, dehydrated in graded ethanol and acetone, embedded in Epon 812 mixture, and sectioned with a LKB-ultramicrotome. the ultrathin sections were contrasted with uranyl acetate and lead citrate and observed with a JEOL-100B electron microscope. The results were as follws: 1. The granular gland in the amphibian skin consisted of the glandular epithelial and the myoepithelial cells. 2. The epithelial cells of the granular gland in the amphibian skin consisted of the dark cells but the light cells were also observed in that of Bombina orientalis. 3. The granular glands of the amphibian skin were in holocrine fashion. 4. The nuclei of the epithelial cells of the amphibian cutaneous granular glands were round or oval and showed small and large inforldings of nuclear envelope. Heterochromatins were mainly distributed near the nuclear envelope. Mitochondria were mainly distributed in the perinuclear portion and rough-surfaced endoplasmic reticulums were developed in the cytoplasm but smooth-surfaced endoplasmic reticulums were not well developed. 5. Secretory granules were round or oval and electron-dense and less electron-dense granules were observed. 6. The authors infer that the differences in electron density of the secretory granules in the granular glands of the amphibian skin are due to difference in the concentrations of secretory substances as related to the processes of its formation, and that those chemical components are identical.

• The Korean Journal of Zoology
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• v.21 no.1
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• pp.29-39
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• 1978

The authors observed the ultrastructure of the mucous glandular epithelial cells in the amphibian skin by mean of electron microscope. The specimens from the experimental animals were fixed in 2.5% glutaraldehyde-oaraformaldehyde fixative in phosphate buffer at pH 7.2 prior to fixation in 1% osmium tetroxide, dehydrated in graded ethanol and acetone, embedded in Epon 812 mixture, and sectioned with Sorvall MT-2 ultramicrotome. The ultrasections were contrasted with uranyl acetate and lead citrate and observed with a JEOL-100B electron microscope. The results were as follows: 1. The cutaneous mucous glands in amphibia consisted of the glandular epithelial and the myoepithelial cells. 2. Several different cells in ultrastructure were observed in the mucous glandular epithelium of the adult amphibian skin. a. The dark and the light cells were observed in Hynobius leechi. b. The mitochondria-rich and the round secretory granule-containing cells were observed in Bombina orientalis. c. The round secretory granule-containing and the foam-like granule mass-containing cells were observed in Kaloula tornieri. d. The cutaneous mucous gland of Rana nigromaculata were divided into two types: A and B-type glands. In the A-type mucous gland, the mitochondria-rich and the round secretory granule-containing cells and in the B-type mucous gland, the mitochondria-rich, the secretory granule-containing and the ER-rich cells were observed. 3. Based upon the above findings, the authors infer that the mucous granular epithelium of the amphibian skin consists of the mitochondria-rich undifferentiated, the secetory granule-containing and mature, and the ER-rich evacuated cells.

• Animal Bioscience
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• v.35 no.9
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• pp.1340-1350
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• 2022

Objective: Luxi Black Head sheep (LBH) is the first crossbreed specialized for meat production and was developed by crossbreeding Black Head Dorper sheep (DP) and Small Tailed Han sheep (STH) in the farming areas of northern China. Research on the genomic variations and selection signatures of LBH caused by continuous artificial selection is of great significance for identifying the genetic mechanisms of important traits of sheep and for the continuous breeding of LBH. Methods: We explored the genetic relationships of LBH, DP, and several Mongolian sheep breeds by constructing phylogenetic tree, principal component analysis and linkage disequilibrium analysis. In addition, we analysed 29 whole genomes of sheep. The genome-wide selection signatures have been scanned with four methods: heterozygosity (H_P), fixation index (F_ST), cross-population extended haplotype homozygosity (XP-EHH) and the nucleotide diversity (𝜃_π) ratio. Results: The genetic relationships analysis showed that LBH appeared to be an independent cluster closer to DP. The candidate signatures of positive selection in sheep genome revealed candidate genes for developmental process (HoxA gene cluster, BCL2L11, TSHR), immunity (CXCL6, CXCL1, SKAP2, PTK6, MST1R), growth (PDGFD, FGF18, SRF, SOCS2), and reproduction (BCAS3, TRIM24, ASTL, FNDC3A). Moreover, two signalling pathways closely related to reproduction, the thyroid hormone signalling pathway and the oxytocin signalling pathway, were detected. Conclusion: The selective sweep analysis of LBH genome revealed candidate genes and signalling pathways associated with developmental process, immunity, growth, and reproduction. Our findings provide a valuable resource for sheep breeding and insight into the mechanisms of artificial selection.

• Journal of Trauma and Injury
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• v.36 no.3
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• pp.196-205
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• 2023

Purpose: Surgical stabilization of rib fractures (SSRF) is widely used in patients with flail chests, and several studies have reported the efficacy of SSRF even in multiple rib fractures. However, few reports have discussed the hardware failure (HF) of implanted plates. We aimed to evaluate the clinical characteristics of patients with HF after SSRF and further investigate the related factors. Methods: We retrospectively reviewed the electronic medical records of patients who underwent SSRF for multiple rib fractures at a level I trauma center in Korea between January 2014 and January 2021. We defined HF as the unintentional loosening of screws, dislocation, or breakage of the implanted plates. The baseline characteristics, surgical outcomes, and types of HF were assessed. Results: During the study period, 728 patients underwent SSRF, of whom 80 (10.9%) were diagnosed with HF. The mean age of HF patients was 56.5±13.6 years, and 66 (82.5%) were men. There were 59 cases (73.8%) of screw loosening, 21 (26.3%) of plate breakage, 17 (21.3%) of screw migration, and seven (8.8%) of plate dislocation. Nine patients (11.3%) experienced wound infection, and 35 patients (43.8%) experienced chronic pain. A total of 21 patients (26.3%) underwent reoperation for plate removal. The patients in the reoperation group were significantly younger, had fewer fractures and plates, underwent costal fixation, and had a longer follow-up. There were no significant differences in subjective chest symptoms or lung capacity. Conclusions: HF after SSRF occurred in 10.9% of the cases, and screw loosening was the most common. Further longitudinal studies are needed to identify risk factors for SSRF failure.

• 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.

• Journal of Korean Society of Forest Science
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• v.113 no.2
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• pp.198-209
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• 2024

This study aimed to investigate the impact of light intensity, manipulated through different shading levels, on the growth and physiological responses of Thermopsis lupinoides. To assess the effects of shading treatments, we examined leaf mass per area, chlorophyll content, chlorophyll fluorescence response, and photosynthetic characteristics. T. lupinoidesexhibited adaptive responses under low light conditions (50% shading), showing increased leaf area and decreased leaf mass per area as shading levels increased. These changes indicate morpho-physiological adaptations to reduced light availability. At 50% shading, the physiological and ecological responses were favorable, with optimal photosynthetic functions including chlorophyll content, photosynthesis saturation point, photosynthetic rate, carbon fixation efficiency, stomatal conductance, transpiration rate, and water use efficiency. However, at 95% shading, the essential light conditions for growth were not met, significantly impairing photosynthetic functions. Consequently, 50% shading was determined to be the most optimal condition for T. lupinoides growth. These findings provide valuable insights for effective ex-situconservation practices and site selection for T. lupinoides, serving as foundational data for habitat restoration efforts.

• Journal of The Korean Association For Science Education
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• v.26 no.6
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• pp.703-722
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• 2006

The purpose of this study is to investigate the characteristics of abduction suggested by C. S. Peirce, and to discuss its implications in science education. Peirce's abduction is the logic of generating hypothesis. Abduction is a kind of logical inference, which colligates general rule and the observed result, and then it makes us judge the observed result as a case of the general rule on the basis of their resemblance. The process of abduction is also the logic of inquiry. In a Peirce's view, inquiry is a struggle for escaping from the condition of 'doubt' and to 'belief the nature of which is the establishment of habits. Because what habit an object has is its whole meaning, in his views, the fixation of belief is the way of attaining the truth related to it. The beliefs of individuals, however, are always fallible. So, to attain a truth, we need the terminal opinion of community of inquiry that could conduct infinite inquiry. These characteristics of Peirce's abduction give suggestions in science education as follows; firstly, hypothesis generating which transforms the condition of 'doubt' into the 'belief by considering practical effects should be highlighted, secondly, logical inference which makes us judge the observed result as a case of the general rule on the basis of resemblance should be highlighted, and thirdly, communities of inquiry which stand on the view of modest realism should be intended toward. These results could be expected in playing a role in critical discussion on science education relating to abduction.