• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.5
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• pp.30-39
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• 2023

Large dams, which are critical infrastructures for disaster prevention, are exposed to various risks such as aging, floods, and earthquakes. Better dam safety inspection and diagnosis using digital transformation technologies are needed. Traditional visual inspection methods by human inspectors have several limitations, including many inaccessible areas, danger of working at heights, and know-how based subjective inspections. In this study, drone photogrammetry was performed on two large dams to evaluate the applicability of digital data-based dam safety inspection and propose a data management methodology for continuous use. High-quality 3D digital models with GSD (ground sampling distance) within 2.5 cm/pixel were generated by flat double grid missions and manual photography methods, despite reservoir water surface and electromagnetic interferences, and severe altitude differences ranging from 42 m to 99.9 m of dam heights. Geometry profiles of the as-built conditions were easily extracted from the generated 3D mesh models, orthomosaic images, and digital surface models. The effectiveness of monitoring dam deformation by photogrammetry was confirmed. Cracks and deterioration of dam concrete structures, such as spillways and intake towers, were detected and visualized efficiently using the digital 3D models. This can be used for safe inspection of inaccessible areas and avoiding risky tasks at heights. Furthermore, a methodology for mapping the inspection result onto the 3D digital model and structuring a relational database for managing deterioration information history was proposed. As a result of measuring the labor and time required for safety inspection at the SYG Dam spillway, the drone photogrammetry method was found to have a 48% productivity improvement effect compared to the conventional manpower visual inspection method. The drone photogrammetry-based dam safety inspection is considered very effective in improving work productivity and data reliability.

• Journal of the Korean Institute of Gas
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• v.27 no.4
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• pp.12-18
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• 2023

The effective evacuation strategy according to the accident scenario is crucial to minimize human casualties in the event of toxic gas leak accidents. In this study, the effect of the direction of a building and the location of an industrial complex on the increase in indoor concentration and outdoor diffusion was examined under the same leakage conditions, and effective evacuation criteria were established. In addition, the guidelines for building directions were suggested when constructing buildings that would mitigate human damage caused by chemical accidents. Three scenarios where buildings faced the front, side, and rear of the leakage direction were investigated through CFD simulations. The results revealed that when the building faced the industrial complex, both indoor and outdoor average gas concentrations increased significantly, reaching up to 120 times higher than the other two orientations. Moreover, the indoor space was filled with toxic gas substances more than twice in the same time due to the rapid increase of indoor concentration rate. In cases where the building's windows were positioned at the front, toxic gas stagnation occurred around the building due to pressure differences and reduced flow velocities. Based on our findings, the implementation of these guidelines will contribute to safeguarding residents by minimizing exposure to toxic gas during chemical accidents.

• Journal of Korean Medicine Rehabilitation
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• v.34 no.2
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• pp.15-28
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• 2024

Objectives We used the D-galactose (D-gal) induced C2C12 myoblast senescence model to investigate whether ethanol extract of Perilla. fructescens leaves (EEPF) could delay cellular senescence and regulate related mechanisms. Methods C2C12 myogenic cells were cultured in an incubator under 37 ℃ and 5% CO₂ conditions. EEPF, dried perilla leaves were pulverized and extracted at 1:10 (v/v) at 50 ℃ for 4 hours. Cell counting kit-8 and western blot analysis was performed. Annexin V-FITC apoptosis detection kit and DAPI staining was applied. Catalase (CAT), glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC), superoxide dismutase (SOD), and malondialdehyde analysis kits were used. To measure the level of reactive oxygen species generation, staining and flow cytometry was used. To analyze the mitochondrial activity, membrane potential changes were measured using JC-1. 𝛽-gal activity was analyzed using SA-𝛽-gal staining solution, and DNA damage was analyzed by using 𝛾-H2AX. Quantikine ELISA kit was used to analyze inflammatory cytokine production. Results According to the results of this study, EEPF significantly alleviated the decrease in cell viability in C2C12 cells treated with D-gal and suppressed the decrease in the expression of proliferating cell nuclear antigen. EEPF also markedly blocked D-gal-induced C2C12 cell apoptosis and restored reduced activity of CAT, GSH-Px, T-AOC, SOD. In addition, EEPF suppressed the decrease in 𝛽-galactosidase activity, the induction of DNA damage and the increase in expression of senescence-associated secretory phenotype proteins such as p16, p53 and p21 in D-gal-treated C2C12 cells. Furthermore, EEPF significantly attenuated D-gal-induced production and expression of inflammatory cytokines such as interleukin (IL)-6 and IL-18. Conclusions The results of this study indicate that EEPF can be used as a potential candidate for the prevention and treatment of muscle aging.

• Journal of the Korean Recycled Construction Resources Institute
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• v.12 no.2
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• pp.229-238
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• 2024

This study evaluated the odor removal performance of a bacteria-based odor reduction kit. The bacteria used were Rhodobacter capsulatus, Paracoccus limosus, and Brevibacterium hankyongi, which can remove ammonia (NH₃), hydrogen sulfide (H₂S), total nitrogen (T-P), and total phosphorus (T-N), which are odor pollutants. The materials used were bacteria and porous aggregates (expanded vermiculite, zeolite beads, activated carbon), and the combination of the materials varied depending on the removal mechanism. Materials with a physical adsorption mechanism (zeolite beads and activated carbon) gradually slowed down the concentration reduction rate of odor pollutants (NH₃, H₂S, T-P, and T-N), and had no further effect on reducing the concentration of odor pollutants after 60 hours. Expanded vermiculite, in which bacteria that remove odors through a bio-adsorption mechanism were immobilized, had a continuous decrease in concentration, and the concentration of odor pollutants reached 0 ppm after 108 hours. As a result, the odor removal performance of materials with physical adsorption mechanisms in actual river water did not meet the odor emission standard required by the Ministry of Environment, while the expanded vermiculite immobilized with bacteria satisfied the odor emission permissible standard and achieved water quality grade 1.

• Korean Journal of Psychosomatic Medicine
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• v.32 no.1
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• pp.24-33
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• 2024

Objectives : The purpose of this study was to investigate individual- and community-level factors on suicidal ideation and suicide attempt among Korean adults. Methods : This study was conducted on 225,965 adults collected through data from the 2021 Community Health Survey and the Korean Statistical Information Service (KOSIS). The general characteristics, suicidal behavior (e.g., suicidal ideation, and suicide attempts), and community-level characteristics of the study subjects were analyzed using frequency (%) and mean (standard deviation). The effects on individual- and community-level factors on suicidal ideation and suicide attempts was analyzed using multilevel logistic regression models. Results : The community-level factor associated with suicidal ideation was unmet health care (Odds Ratio [OR]=1.053, 95% CI=1.035-1.071), and the community-level factor associated with suicide attempt was the aging rate (OR=1.015, 95% CI=1.001-1.030). Regarding health-related variables, the individual-level factors associated with suicidal ideation were stress status (OR=9.388, 95% CI=8.629-10.213), depressive experience in the past year (OR=6.737, 95% CI=6.454-7.032), and the predominantly individual-level factors associated with suicide attempt were also stress status (OR=5.213, 95% CI=3.699-7.347), and depressive experience in the last one year (OR=13.433, 95% CI: 11.247-16.044). Conclusions : We confirmed individual-level and community-level factors influencing suicidal ideation and suicide attempt. Through these findings, we need to establish suicide prevention policies, considering managing individual-level factors such as stress and depression as well as community-level factors such as unmet health care.

• Food Science and Preservation
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• v.30 no.3
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• pp.526-537
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• 2023

This study aimed to evaluate the antioxidant and hepatoprotective effects of aqueous and 60% ethanol extracts of Allium ochotense Prokh. against alcohol-induced cytotoxicity as well as on the activities of alcohol-metabolic enzymes. Antioxidant effects of the extracts were analyzed using 3-ethylbenzothiazoline-6-sulfonic acid, 1,1-diphenyl-2-picrylhydrazl, ferric reducing antioxidant power, and malondialdehyde assays, and found that both extracts exhibited considerable antioxidant activities. Additionally, both extracts showed synergistic effects on the activities of alcohol-metabolic enzymes, such as alcohol dehydrogenase, but not on the activity of aldehyde dehydrogenase. In addition, 2'-7'-dichlorodihydrofluorescein diacetate (DCF-DA) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays revealed that aqueous and 60% ethanol extracts reduced oxidative stress and increased cell viability. Moreover, both extracts regulated the expression of apoptosis-related proteins, namely B-cell lymphoma (BCl-2), BCl-2 associated X (BAX), and pro-caspase-3, in HepG2 cells. In conclusion, aqueous and 60% ethanol extracts of A. ochotense Prokh. might be valuable functional materials derived from natural resources for the prevention of ethanol-induced cytotoxicity.

• Journal of the Korea Institute of Building Construction
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• v.24 no.1
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• pp.109-120
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• 2024

For successful waterproofing construction, it is very important to secure construction quality as well as material performance of waterproofing materials used in construction. Due to the long-term cost reduction policy following the economic downturn in the construction market, most construction companies are using general low-priced waterproof materials rather than high-quality waterproof materials without clear quality control standards. Without clear education on construction, construction is being carried out with meaning only on construction activities. In addition, the waterproofing method applied in combination is a situation where water leakage occurs due to waterproofing failure due to insufficient construction quality because the construction method is complicated. Therefore, it is necessary to review the quality control measures(design, materials, construction) for successful waterproofing work and improve problems that are derived so that stable waterproofing work can be done. In order to expect the leakage prevention effect of a building, first, it is required to select appropriate materials for each part of the building and environment in the design stage, and the selected materials must satisfy all items of the Korean Industrial Standard(KS). Second, to secure the quality of waterproofing construction, sincere construction by workers is required. In this paper, we tried to describe "review of waterproof design", "constructor education", "site inspection", and "criticism(correction/supplementation)" as quality control measures after material selection.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.1
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• pp.1-11
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• 2024

The purpose of this paper is to suggest a method for applying a reasonable dam axial seismic load loading method and load-bearing capacity evaluation method in the dynamic analysis of the pier part of a concrete dam to which the seismic force of the collapse prevention level is applied. To this end, the pier part of a concrete dam was selected as a target facility, and the characteristics of the dynamic behavior in the axial direction of the weir dam were analyzed through dynamic analysis applying various weir widths, and 'U.S. The load-bearing capacity evaluation was performed by applying the RC hydraulic structure evaluation technique suggested by the Army Corps, 2007'. As a result of the study, when applying seismic force in the axial direction of the pier part, it is more realistic to assume that the axial direction of the weir part dam behaves as a rigid body and 'U.S. Army Corps, 2007' suggested that the method of reviewing the load-bearing capacity for moment and shear was considered reasonable, so it was concluded that improvement of the current evaluation method was necessary. If the improvement of the research result is applied, it will have the effect of deriving more reasonable evaluation results than the current seismic performance evaluation method using CLE. It is judged that additional research is needed in the future on the torsional moment occurring in the pier part.

• Journal of Nutrition and Health
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• v.57 no.1
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• pp.43-52
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• 2024

Purpose: Cancer is the leading cause of death in Koreans, with breast cancer being the most common among women. Breast cancer readily metastasizes, and the existing treatment processes impose a significant burden on patients. This study examined whether pomegranate-derived exosome-like nanovesicles (PNVs) have anti-cancer effects by inhibiting cell infiltration and metastasis while increasing apoptosis on breast cancer MDA-MB-231 cells. Methods: Initially, exosome-like nanovesicles were isolated from pomegranate using ultracentrifugation. Subsequently, the size range of these nanovesicles was confirmed using nanoparticle tracking analysis. The ability of breast cancer MDA-MB-231 cells to internalize these natural nanovesicles was assessed with flourescence microscope. The anti-cancer effects of the PNVs were confirmed by applying various concentrations of PNVs (10, 50, 100 ㎍/mL) to MDA-MB-231 cells and systematically assessing their impact on cell viability and migration. Results: The round shape of the lipid bilayer in the PNVs was confirmed, providing crucial insights into their structural properties. We demonstrate that PNVs-associated DiD dye can be efficiently internalized by the MDA-MB-231 cells. The data showed that the PNVs inhibited cell viability, invasion rates, and migration in MDA-MB-231 cells. In addition, PNVs were absorbed into the MDA-MB-231 cells, leading to an increased expression of apoptosis proteins, such as cleaved caspase-3 and phosphorus-JNK, in a concentration-dependent manner. Furthermore, a reduction in cell infiltration and decreased expression of the transition markers MMP-2 and MMP-9 proteins were observed. Conclusion: For the first time, this study suggests that PNVs may be useful in the prevention or treatment of breast cancer by inhibiting the infiltration and metastasis of MDA-MB-231 cells and inducing apoptosis.

• Journal of Environmental Health Sciences
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• v.50 no.2
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• pp.102-112
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• 2024

Background: Despite the rise in the number of domestic indoor climbing gyms, there is a lack of specific hygiene standards and research on the holds installed in them. Holds can act as vectors for microbial transmission through the hands, posing a risk of infectious diseases, especially with damaged skin. Objectives: The aim of this study is to investigate the contamination level and species of microorganisms on holds according to the management methods practiced in indoor climbing gyms and identify effective strategies for reducing microbial contamination. Methods: We investigated factors that may influence microbial contamination of holds, including hold management methods, user information, and hygiene management at three climbing gyms in Seoul. A total of 72 holds were sampled, 18 for each management method of brushing, high-pressure washing, and ethanol disinfection. Samples were cultured on LB and blood agar at 37℃ for 48 hours to calculate CFUs. PCR assay targeting 16S rRNA was carried out to identify microorganisms. Dunn-Bonferroni was employed to see the microbial reduction effect of the management method and the difference in microbial contamination by management method and climbing gym. Results: As a result of microbial identification, microorganisms such as Bacillus, Staphylococcus, and Micrococcus, which were derived from various environments such as skin and soil, were discovered on the surface of the climbing hold. Among the discovered microorganisms, some species had potential pathogenic properties that could cause food poisoning, gastrointestinal disease, bacteremia, and sepsis. All hold management methods were effective in reducing microorganisms (p<0.05), with ethanol disinfection being the most effective (p<0.001). Conclusions: Our results indicate that there are potential pathogens on holds that demand thorough management for microbial prevention. Proposed methods include regular brushing and ethanol disinfection in addition to high-pressure washing with long cycles, which are the existing forms of hold management. Further studies on shoe management are advised to curb soil-derived microorganisms.