• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.4
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• pp.381-392
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• 2022

Objectives: Objective of this study is to review briefly exposure characteristics, monitoring instruments and threshold limit values for extremely low frequency-magnetic field (ELF-MF) methods. This study was undertaken through brief literature review. We performed a literature search in PubMed to identify ELF-MF studies conducted in workplaces. Initial search keywords such as 'extremely low frequency-magnetic field (ELF-MF)' and 'electromagnetic fields (EMF)' combined or singly. We limited our review to occupational rather than general nonworkplace environmental exposures. Methods: The contents we reviewed: key industry and occupations generating ELF-MF, several direct-reading instruments monitoring ELF-MF and threshold limit values (TLV) preventing health effects may be caused by the exposure to ELF-MF. Results: The industries related to the generation and supply of electricity, electrolytic installations, welding, and induction heating and more were regarded as high ELF-MF exposure industries. All jobs handling or employed performed in power cable lines, electrical wiring, and electrical equipment are found to be exposed to ELF-MF. Threshold or ceiling limit, 1,000 µT, is established to prevent acute effects of exposure to low-frequency EMFs on the nervous system: the direct stimulation of nerve and muscle tissues and the induction of retinal phosphenes. The International Agency for Research on Cancer (IARC) has classified ELF-MF as possibly carcinogenic to humans chiefly based on epidemiological studies on childhood leukemia. However, a causal relationship between magnetic fields and several types of cancer including childhood leukemia has not been established nor has any other long-term effects. Risk management using precautionary measures, has been initiated by the US and EU to prevent chronic health effects related to ELF-MF exposure in workplaces. Conclusion: This study recommends the implementation of various measures such as theestablishment of occupational exposure limit values for ELF-MF and precautionary principle to prevent potential chronic occupational health effects may be caused by ELF-MF in Korea.

• Nutrition Research and Practice
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• v.16 no.3
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• pp.330-343
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• 2022

BACKGROUND/OBJECTIVES: Zanthoxylum schinifolium is traditionally used as a spice for cooking in East Asian countries. This study was undertaken to evaluate the anti-proliferative potential of ethanol extracts of Z. schinifolium leaves (EEZS) against human bladder cancer T24 cells. MATERIALS/METHODS: Subsequent to measuring the cytotoxicity of EEZS, the anti-cancer activity was measured by assessing apoptosis induction, reactive oxygen species (ROS) generation, and mitochondrial membrane potential (MMP). In addition, we determined the underlying mechanism of EEZS-induced apoptosis through various assays, including Western blot analysis. RESULTS: EEZS treatment concentration-dependently inhibited T24 cell survival, which is associated with apoptosis induction. Exposure to EEZS induced the expression of Fas and Fas-ligand, activated caspases, and subsequently resulted to cleavage of poly (ADP-ribose) polymerase. EEZS also enhanced the expression of cytochrome c in the cytoplasm by suppressing MMP, following increase in the ratio of Bax:Bcl-2 expression and truncation of Bid. However, EEZS-mediated growth inhibition and apoptosis were significantly diminished by a pan-caspase inhibitor. Moreover, EEZS inhibited activation of the phosphoinositide 3-kinase (PI3K)/Akt pathway, and the apoptosis-inducing potential of EEZS was promoted in the presence of PI3K/Akt inhibitor. In addition, EEZS enhanced the production of ROS, whereas N-acetyl cysteine (NAC), a ROS scavenger, markedly suppressed growth inhibition and inactivation of the PI3K/Akt signaling pathway induced by EEZS. Furthermore, NAC significantly attenuated the EEZS-induced apoptosis and reduction of cell viability. CONCLUSIONS: Taken together, our results indicate that exposure to EEZS exhibits anti-cancer activity in T24 bladder cancer cells through ROS-dependent induction of apoptosis and inactivation of the PI3K/Akt signaling pathway.

• Journal of Life Science
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• v.32 no.9
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• pp.712-720
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• 2022

The purpose of this study was to investigate the efficacy of rat corneal-derived epithelial cells as an in vitro model to evaluate the harmfulness of the cornea caused by particulate matter 2.5 (PM_2.5). To establish an experimental model for the effect of PM_2.5 on corneal epithelial cells, it was confirmed that primary cultured cells isolated from rat eyes were corneal epithelial cells through pan-cytokeratin staining. Our results showed that PM_2.5 treatment reduced cell viability of primary rat corneal epithelial (RCE) cells, which was associated with the induction of apoptosis. PM_2.5 treatment also increased the generation of reactive oxygen species due to mitochondrial dysfunction. In addition, the production of nitric oxide and inflammatory cytokines was increased in PM_2.5-treated RCE cells. Furthermore, through heatmap analysis showing various expression profiling between PM_2.5-exposed and unexposed RCE cells, we proposed five genes, including BLNK, IL-1RA, Itga2b, ABCb1a and Ptgs2, as potential targets for clinical treatment of PM-related ocular diseases. These findings indicate that the primary RCE cell line is a useful in vitro model system for the study of PM_2.5-mediated pathological mechanisms and that PM2.5-induced oxidative and inflammatory responses are key factors in PM2.5-induced ocular surface disorders.

• Journal of Life Science
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• v.32 no.5
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• pp.348-354
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• 2022

The leaves, stems, seeds, and roots of Dendropanax morbifera have been used since ancient times as folk medicines for the treatment of headaches, skin diseases, infectious diseases, and other ailments. This study investigated the antioxidant, alcohol metabolism, and hepatoprotective effects of D. morbifera leaf and stem water extracts. The total polyphenol content of the D. morbifera leaf and stem water extracts was 49.56 mg tannic acid equivalent (TAE)/g, and the 1,1-diphenyl-2-picrylhydrazy (DPPH) radical scavenging activity of the D. morbifera leaf and stem water extracts was 84.09% at 1,000 ㎍/ml concentration. The effects of D. morbifera leaf and stem water extracts on alcohol metabolism were determined by measuring the generation of reduced nicotinamide adenine dinucleotide (NADH) by alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH). The ADH and ALDH activities of D. morbifera leaf and stem water extracts were increased in a dose-dependent manner at 37.68% and 41.67%, respectively, at a 1,000 ㎍/ml concentration. The D. morbifera leaf and stem water extracts showed significant protective effects against tacrine-induced cytotoxicity in HepG2 cells at 50 ㎍/ml. Based on our results, we concluded that D. morbifera leaf and stem water extracts may be used as major pharmacological agents, such as antioxidants, alcohol metabolism, and anti-hepatitis remedies.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.56-56
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• 2001

The exogenous gene transfer by intracytoplasmic sperm injection (ICSI) procedure has been recently used to produce transgenic mice and pigs. Sperm-mediated DNA transfer has the potential to markedly simplify the generation of transgenic animals. This method may serve as an alternative to the pronucleus injection of DNA for the production of transgenic pigs. Therefore, in this study, we investigated the expression of transgene after co-injection of spermatozoon or sperm head with green fluorescent protein (GFP) gene into in vitro matured porcine oocytes. Spermatozoon and sperm head, that was obtained by sonication, were treated with 0.03% Triton X-100 to remove the membrane. They were preincubated with linearized pEGFP-N1 for 1 min, and then embryos cultured NCSU23 medium for 2.5 days after co-injected of sperm and DNA. We monitored expression of GFP in embryos under epifluorescent microscope. The remove of sperm membrane did not alter the developmental competence of embryos after ICSI. At 7 days following injection, the rates of blastocysts following injection of intact sperm (15.0%), and of sperm with disrupted membrane (14.2%) were higher than that following IVF (10.0%). Porcine oocytes injected with sperm which co-cultured with DNA concentration of 1, 0.1, and 0.01 ng were 60, 65.7 and 75% and 18.5, 37.4 and 22.2% for rates of cleavage and GFP expression, respectively. In vitro matured porcine oocytes injected with sperm and isolated sperm head resulted in 69 and 59.7% of cleavage rates, respectively The rates of embryo GFP expressed did not significantly different between sperm (20.4%) and sperm head (20.0%) injection. The transgenic embryos with the clusters of positive blastomeres were observed under fluorescent microscope. Most of embryos expressed GFP gene showed mosaicism. They showed GFP expression at 1/4, 2/4 and 3/4 of blastomeres at the 4-cell stage. Among these 4-cell embryos, the expression rate of 1/4 blastomere group (54.6%) was higher than the other groups (15.3-30.7%). These results indicate that membrane disrupted sperm could attach with exogenous DNA, and that this procedure may be useful to introduce foreign gene into porcine oocytes. Therefore, our data suggest that the ICSI car be a useful tool to efficiently produce transgenic pig as well as other mammals.

• Journal of Nutrition and Health
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• v.56 no.2
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• pp.140-154
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• 2023

Purpose: Deodeok (Codonopsis lanceolata) is generally used in conventional medicines and is considered to have remedial properties to cure several diseases. However, application of the C. lanceolata bud as a novel food ingredient has not been fully explored. Hydrogen peroxide (H₂O₂) is associated with the production of oxidative damage that results in mutagenesis, carcinogenesis, and cell death. This study examines the neuroprotective effect of C. lanceolate bud extracts (CLBE) on H₂O₂-stimulated apoptosis in SH-SY5Y cells. Methods: C. lanceolata bud of length 10 to 15 cm was collected and extracted using 70% ethanol. Cytotoxicity was evaluated by the EZ-cytox reagent, measurement of lactic dehydrogenase (LDH) release and reactive oxygen species (ROS). The morphological changes of the nuclei were determined using the Hoechst 33258 dye. Enzyme activities were analyzed using the caspase activity assay kit. Related protein expressions were quantified by the Western blot immunoassay in H₂O₂-stimulated SH-SY5Y cells. Results: Cell viability, LDH release and ROS generation, demonstrated neuroprotective effects of CLBE in H₂O₂-stimulated SH-SY5Y cells. The occurrence of apoptosis in H₂O₂-stimulated cells was confirmed by caspase activity, which was increased in H₂O₂-stimulated SH-SY5Y cells compared to the unexposed group. Pretreatment of CLBE was observed to inhibit the H₂O₂-stimulated apoptosis. In addition, exposure to CLBE resulted in increased expression of the Bcl-2 (B cell lymphoma 2) protein and decreased expression of the Bax (Bcl2 associated X) protein. Conclusion: This study shows that exposure to CLBE alleviates the H₂O₂-stimulated neuronal damage in SH-SY5Y cells. Our results indicate the potential application of CLBE in neurodegenerative disease therapy or prevention.

• Biomolecules & Therapeutics
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• v.31 no.1
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• pp.97-107
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• 2023

Aristolochic acid (AA), extracted from Aristolochiaceae plants, plays an essential role in traditional herbal medicines and is used for different diseases. However, AA has been found to be nephrotoxic and is known to cause aristolochic acid nephropathy (AAN). AA-induced acute kidney injury (AKI) is a syndrome in AAN with a high morbidity that manifests mitochondrial damage as a key part of its pathological progression. Melatonin primarily serves as a mitochondria-targeted antioxidant. However, its mitochondrial protective role in AA-induced AKI is barely reported. In this study, mice were administrated 2.5 mg/kg AA to induce AKI. Melatonin reduced the increase in Upro and Scr and attenuated the necrosis and atrophy of renal proximal tubules in mice exposed to AA. Melatonin suppressed ROS generation, MDA levels and iNOS expression and increased SOD activities in vivo and in vitro. Intriguingly, the in vivo study revealed that melatonin decreased mitochondrial fragmentation in renal proximal tubular cells and increased ATP levels in kidney tissues in response to AA. In vitro, melatonin restored the mitochondrial membrane potential (MMP) in NRK-52E and HK-2 cells and led to an elevation in ATP levels. Confocal immunofluorescence data showed that puncta containing Mito-tracker and GFP-LC3A/B were reduced, thereby impeding the mitophagy of tubular epithelial cells. Furthermore, melatonin decreased LC3A/B-II expression and increased p62 expression. The apoptosis of tubular epithelial cells induced by AA was decreased. Therefore, our findings revealed that melatonin could prevent AA-induced AKI by attenuating mitochondrial damage, which may provide a potential therapeutic method for renal AA toxicity.

• Tunnel and Underground Space
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• v.33 no.3
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• pp.189-207
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• 2023

In the present study, the thermoshearing experiment on a rough rock fracture were modeled using a three-dimensional grain-based distinct element model (GBDEM). The experiment was conducted by the Korea Institute of Construction Technology to investigate the progressive shear failure of fracture under the influence of thermal stress in a critical stress state. The numerical model employs an assembly of multiple polyhedral grains and their interfaces to represent the rock sample, and calculates the coupled thermo-mechanical behavior of the grains (blocks) and the interfaces (contacts) using 3DEC, a DEM code. The primary focus was on simulating the temperature evolution, generation of thermal stress, and shear and normal displacements of the fracture. Two fracture models, namely the mated fracture model and the unmated fracture model, were constructed based on the degree of surface matedness, and their respective behaviors were compared and analyzed. By leveraging the advantage of the DEM, the contact area between the fracture surfaces was continuously monitored during the simulation, enabling an examination of its influence on shear behavior. The numerical results demonstrated distinct differences depending on the degree of the surface matedness at the initial stage. In the mated fracture model, where the surfaces were in almost full contact, the characteristic stages of peak stress and residual stress commonly observed in shear behavior of natural rock joints were reasonably replicated, despite exhibiting discrepancies with the experimental results. The analysis of contact area variation over time confirmed that our numerical model effectively simulated the abrupt normal dilation and shear slip, stress softening phenomenon, and transition to the residual state that occur during the peak stress stage. The unmated fracture model, which closely resembled the experimental specimen, showed qualitative agreement with the experimental observations, including heat transfer characteristics, the progressive shear failure process induced by heating, and the increase in thermal stress. However, there were some mismatches between the numerical and experimental results regarding the onset of fracture slip and the magnitudes of fracture stress and displacement. This research was conducted as part of DECOVALEX-2023 Task G, and we expect the numerical model to be enhanced through continued collaboration with other research teams and validated in further studies.

• Biomolecules & Therapeutics
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• v.31 no.4
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• pp.446-455
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• 2023

The mechanistic functions of 3-deoxysappanchalcone (3-DSC), a chalcone compound known to have many pharmacological effects on lung cancer, have not yet been elucidated. In this study, we identified the comprehensive anti-cancer mechanism of 3-DSC, which targets EGFR and MET kinase in drug-resistant lung cancer cells. 3-DSC directly targets both EGFR and MET, thereby inhibiting the growth of drug-resistant lung cancer cells. Mechanistically, 3-DSC induced cell cycle arrest by modulating cell cycle regulatory proteins, including cyclin B1, cdc2, and p27. In addition, concomitant EGFR downstream signaling proteins such as MET, AKT, and ERK were affected by 3-DSC and contributed to the inhibition of cancer cell growth. Furthermore, our results show that 3-DSC increased redox homeostasis disruption, ER stress, mitochondrial depolarization, and caspase activation in gefitinib-resistant lung cancer cells, thereby abrogating cancer cell growth. 3-DSC induced apoptotic cell death which is regulated by Mcl-1, Bax, Apaf-1, and PARP in gefitinib-resistant lung cancer cells. 3-DSC also initiated the activation of caspases, and the pan-caspase inhibitor, Z-VAD-FMK, abrogated 3-DSC induced-apoptosis in lung cancer cells. These data imply that 3-DSC mainly increased mitochondria-associated intrinsic apoptosis in lung cancer cells to reduce lung cancer cell growth. Overall, 3-DSC inhibited the growth of drug-resistant lung cancer cells by simultaneously targeting EGFR and MET, which exerted anti-cancer effects through cell cycle arrest, mitochondrial homeostasis collapse, and increased ROS generation, eventually triggering anti-cancer mechanisms. 3-DSC could potentially be used as an effective anti-cancer strategy to overcome EGFR and MET target drug-resistant lung cancer.

• Journal of Intelligence and Information Systems
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• v.29 no.2
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• pp.219-240
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• 2023

Conversational AI which allows users to interact with satisfaction is a long-standing research topic. To develop conversational AI, it is necessary to build training data that reflects real conversations between people, but current Korean datasets are not in question-answer format or use honorifics, making it difficult for users to feel closeness. In this paper, we propose a conversation dataset (KOMUChat) consisting of 30,767 question-answer sentence pairs collected from online communities. The question-answer pairs were collected from post titles and first comments of love and relationship counsel boards used by men and women. In addition, we removed abuse records through automatic and manual cleansing to build high quality dataset. To verify the validity of KOMUChat, we compared and analyzed the result of generative language model learning KOMUChat and benchmark dataset. The results showed that our dataset outperformed the benchmark dataset in terms of answer appropriateness, user satisfaction, and fulfillment of conversational AI goals. The dataset is the largest open-source single turn text data presented so far and it has the significance of building a more friendly Korean dataset by reflecting the text styles of the online community.