• Journal of Korean Society for Quality Management
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• v.52 no.1
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• pp.43-56
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• 2024

Purpose: The injection molding process, crucial for plastic shaping, encounters difficulties in sustaining product quality when replacing injection machines. Variations in machine types and outputs between different production lines or factories increase the risk of quality deterioration. In response, the study aims to develop a system that optimally adjusts conditions during the replacement of injection machines linked to molds. Methods: Utilizing a dataset of 12 injection process variables and 52 corresponding sensor variables, a predictive model is crafted using Decision Tree, Random Forest, and XGBoost. Model evaluation is conducted using an 80% training data and a 20% test data split. The dependent variable, classified into five characteristics based on temperature and pressure, guides the prediction model. Bayesian optimization, integrated into the selected model, determines optimal values for process variables during the replacement of injection machines. The iterative convergence of sensor prediction values to the optimum range is visually confirmed, aligning them with the target range. Experimental results validate the proposed approach. Results: Post-experiment analysis indicates the superiority of the XGBoost model across all five characteristics, achieving a combined high performance of 0.81 and a Mean Absolute Error (MAE) of 0.77. The study introduces a method for optimizing initial conditions in the injection process during machine replacement, utilizing Bayesian optimization. This streamlined approach reduces both time and costs, thereby enhancing process efficiency. Conclusion: This research contributes practical insights to the optimization literature, offering valuable guidance for industries seeking streamlined and cost-effective methods for machine replacement in injection molding.

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.26.1-26.15
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• 2023

Background: The objective of this study is to investigate the differences in incidence rates of targeted diseases by classification of occupations among construction workers in Korea. Methods: In a subject-based cohort of the Korean Construction Worker's Cohort, we surveyed a total of 1,027 construction workers. As occupational exposure, the classification of occupations was developed using two axes: construction business and job type. To analyze disease incidence, we linked survey data with National Health Insurance Service data. Eleven target disease categories with high prevalence or estimated work-relatedness among construction workers were evaluated in our study. The average incidence rates were calculated as cases per 1,000 person-years (PY). Results: Injury, poisoning, and certain other consequences of external causes had the highest incidence rate of 344.08 per 1,000 PY, followed by disease of the musculoskeletal system and connective tissue for 208.64 and diseases of the skin and subcutaneous tissue for 197.87 in our cohort. We especially found that chronic obstructive pulmonary disease was more common in construction painters, civil engineering welders, and civil engineering frame mold carpenters, asthma in construction painters, landscape, and construction water proofers, interstitial lung diseases in construction water proofers. Conclusions: This is the first study to systematically classify complex construction occupations in order to analyze occupational diseases in Korean construction workers. There were differences in disease incidences among construction workers based on the classification of occupations. It is necessary to develop customized occupational safety and health policies for high-risk occupations for each disease in the construction industry.

• Journal of Microbiology and Biotechnology
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• v.34 no.2
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• pp.289-295
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• 2024

We have developed an aptamer that specifically binds to Porphyromonas gingivalis to reduce the cellular damage caused by P. gingivalis infection and applied it as a biosensor. P. gingivalis is one of the major pathogens causing destructive periodontal disease among the periodontal microorganisms constituting complex biofilms. Porphyromonas gingivalis G-protein (PGP) known to play an important role in the transmission of germs was used as a target protein for the screening of aptamer. The aptamer that has binds to the G-protein of P. gingivalis, was screened and developed through the Systemic Evolution of Ligands by Exponential Energy (SELEX) method. Modified-Western blot analysis was performed with the aptamer which consisted of 38 single-stranded DNA to confirm the selectivity. ELONA (enzyme linked oligonucleotide assay) used to confirm that the aptamer was sensitive to PGP even at low concentration of 1 ㎍/ml. For the rapid detection of P. gingivalis, we constructed a surface plasmon resonance biosensor with SPREETA using the PGP aptamer. It was confirmed that PGP could be detected as low concentration as at 0.1 pM, which is the minimum concentration of aptamer sensor within 5 min. Based on these results, we have constructed a SPREETA biosensor based on aptamer that can bind to P. gingivalis G-protein. It can be used as an infection diagnosis system to rapidly diagnose and analyze oral diseases caused by P. gingivalis.

• Journal of Microbiology and Biotechnology
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• v.34 no.3
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• pp.663-672
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• 2024

The use of nanoparticles as a delivery system for a specific antigen could solve many limitations of mucosal vaccine applications, such as low immunogenicity, or antigen protection and stabilization. In this study, we tested the ability of nasally administered chitosan nanoparticles loaded with glycoprotein B of murine cytomegalovirus to induce an immune response in an animal model. The choice of chitosan nanoparticle type was made by in vitro evaluation of sorption efficiency and antigen release. Three types of chitosan nanoparticles were prepared: crosslinked with tripolyphosphate, coated with hyaluronic acid, and in complex with polycaprolactone. The hydrodynamic size of the nanoparticles by dynamic light scattering, zeta potential, Fourier transform infrared spectroscopy, scanning electron microscopy, stability, loading efficiency, and release kinetics with ovalbumin were evaluated. Balb/c mice were immunized intranasally using the three-dose protocol with nanoparticles, gB, and adjuvants Poly(I:C) and CpG ODN. Subsequently, the humoral and cell-mediated antigen-specific immune response was determined. On the basis of the properties of the tested nanoparticles, the cross-linked nanoparticles were considered optimal for further investigation. The results show that nanoparticles with Poly(I:C) and with gB alone raised IgG antibody levels above the negative control. In the case of mucosal IgA, only gB alone weakly induced the production of IgA antibodies compared to saline-immunized mice. The number of activated cells increased slightly in mice immunized with nanoparticles and gB compared to those immunized with gB alone or to negative control. The results demonstrated that chitosan nanoparticles could have potential in the development of mucosal vaccines.

• Journal of Microbiology and Biotechnology
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• v.34 no.2
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• pp.270-279
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• 2024

Macrophages are versatile immune cells that play crucial roles in tissue repair, immune defense, and the regulation of immune responses. In the context of skeletal muscle, they are vital for maintaining muscle homeostasis but macrophage-induced chronic inflammation can lead to muscle dysfunction, resulting in skeletal muscle atrophy characterized by reduced muscle mass and impaired insulin regulation and glucose uptake. Although the involvement of macrophage-secreted factors in inflammation-induced muscle atrophy is well-established, the precise intracellular signaling pathways and secretion factors affecting skeletal muscle homeostasis require further investigation. This study aimed to explore the regulation of macrophage-secreted factors and their impact on muscle atrophy and glucose metabolism. By employing RNA sequencing (RNA-seq) and proteome array, we uncovered that factors secreted by lipopolysaccharide (LPS)-stimulated macrophages upregulated markers of muscle atrophy and pro-inflammatory cytokines, while concurrently reducing glucose uptake in muscle cells. The RNA-seq analysis identified alterations in gene expression patterns associated with immune system pathways and nutrient metabolism. The utilization of gene ontology (GO) analysis and proteome array with macrophage-conditioned media revealed the involvement of macrophage-secreted cytokines and chemokines associated with muscle atrophy. These findings offer valuable insights into the regulatory mechanisms of macrophage-secreted factors and their contributions to muscle-related diseases.

• International Journal of Stem Cells
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• v.15 no.3
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• pp.270-282
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• 2022

Background and Objectives: Menkes disease (MNK) is a rare X-linked recessive disease, caused by mutations in the copper transporting ATP7A gene that is required for copper homeostasis. MNK patients experience various clinical symptoms including neurological defects that are closely related to the prognosis of MNK patients. Neural stem cells (NSCs) in the hippocampal dentate gyrus (DG) produce new neurons throughout life, and defects in DG neurogenesis are often correlated with cognitive and behavioral problems. However, neurodevelopmental defects in the DG during postnatal period in MNK have not been understood yet. Methods and Results: Mottled-brindled (Mo^Br/y) mice (MNK mice) and littermate controls were used in this study. In vivo microCT imaging and immunohistochemistry results demonstrate that blood vasculatures in hippocampus are abnormally decreased in MNK mice. Furthermore, postnatal establishment of NSC population and their neurogenesis are severely compromised in the DG of MNK mice. In addition, in vitro analyses using hippocampal neurosphere culture followed by immunocytochemistry and immunoblotting suggest that neurogenesis from MNK NSCs is also significantly compromised, corresponding to defective neurogenic gene expression in MNK derived neurons. Conclusions: Our study is the first reports demonstrating that improper expansion of the postnatal NSC population followed by significant reduction of neurogenesis may contribute to neurodevelopmental symptoms in MNK. In conclusion, our results provide new insight into early neurodevelopmental defects in MNK and emphasize the needs for early diagnosis and new therapeutic strategies in the postnatal central nerve system damage of MNK patients.

• Clinical and Experimental Reproductive Medicine
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• v.51 no.3
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• pp.247-259
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• 2024

Objective: Bis-[4-chlorophenyl]-1,1,1-trichloroethane (DDT), one of the most widely used synthetic pesticides, is an endocrine-disrupting chemical with the potential to interfere with the human reproductive system. The effects of DDT and one of its metabolites, p,p'-DDT, on human endometrial stromal cells (ESCs) and health outcomes remain unknown. In this study, we investigated whether p,p'-DDT induces an imbalance in cell proliferation and apoptosis in human ESCs via oxidative stress. Methods: We assessed apoptosis in ESCs by quantifying the expression of markers associated with both intrinsic and extrinsic pathways. Additionally, we measured levels of reactive oxygen species (ROS), antioxidant enzyme activity, and estrogen receptors (ERs). We also examined changes in signaling involving nuclear factor kappa-light-chain-enhancer of activated B cells. Results: Following treatment with 1,000 pg/mL of p,p'-DDT, we observed an increase in Bax expression, a decrease in Bcl-2 expression, and increases in the expression of caspases 3, 6, and 8. We also noted a rise in the generation of ROS and a reduction in glutathione peroxidase expression after treatment with p,p'-DDT. Additionally, p,p'-DDT treatment led to changes in ER expression and increases in the protein levels of phosphatidylinositol 3-kinase (PI3K), phospho-protein kinase B (phospho-AKT), and phospho-extracellular signal-regulated kinase (phospho-ERK). Conclusion: p,p'-DDT was found to induce apoptosis in human ESCs through oxidative stress and an ER-mediated pathway. The activation of the PI3K/AKT and ERK pathways could represent potential mechanisms by which p,p'-DDT prompts apoptosis in human ESCs and may be linked to endometrial pathologies.

• Journal of Korean Physical Therapy Science
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• v.14 no.1_4
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• pp.25-36
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• 2007

The results of researching on duties of physical therapist, understanding of elderly diseases and policies related with elderly welfare came out from the survey before beginning of education to physical therapists who attended National Elderly Welfare Physical Therapist Workshop during Sep. 11th to 14th, 2007. They have already understood about long-term elderly care insurance from the policy, and responded that those policies will bring more advantage to elders. On contrary, negative response had reason of low service quality. About elderly care system, there were positive answer of appropriate alternatives to support them, but also other critics had opinion of inevitable choice for living conservation. About understanding of elderly diseases, there were more comprehension of diseases as age gets higher, but most did not understand dementia and paralysis. Past experience and process of medical treatment for their disease were such arthritis, paralysis, broken bone, and dislocation of joint. Prognosis of technical training was mostly answered positively, but linking with other related disease programs were not welcomed. Most respondents thought that professional training were needed. The results of understanding diseases during senescent had high percentage of understanding as age and education was high, and it had eye upon statistics of the survey (p < 0.05) Most of those questioned responded that it is appropriate to have six working days per week and eight hours of daily work, however, present wage is not reasonable. Most of those questioned had negative response of work independence, and had an-swered that there should be certificates needed in related fields. For difficulties during work period, they had hardship instituting direction of treatment by lack of program, level of wage, and physical difficulties. Physical therapists averagely wished to have fewer than thirty patients per therapist. After the research, physical therapists who work in those facilities of elderly care systems agreed on policies, though it should not lower service quality. In addition, they were pros to have elderly care system, yet they are still inevitable option to maintain living. For work environment, the period of work was appropriate, but had different opinions for work independence and regular number of patients. Therefore, there should be more organized treatment program that also should be linked to other practical programs at this beginning point of the policy enforcement and the time that many therapists hope to work in elderly care system.

• International Commerce and Information Review
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• v.14 no.3
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• pp.585-610
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• 2012

There have been various attempt to offer commercial service of electronic payment. Actually, however, there has been few electronic payment model that are being used commercial service. Among them, it is estimated that only TSU(Trade Service Utility) of SWIFT will be succeed in providing commercial service possibility. In Korea e-L/C Distribution & Management System was constructed and become the first e-L/C service on a global basis via e-Trade Facilitation 3 Years Project and then started offering the world first e-L/C service. Some scholars have insisted the opinion that SWIFT L/C means e-L/C, but such opinion may be wrong because SWIFT L/C means the L/C advised by SWIFT(Society for Worldwid Interbank Financial Telecommunication) under the condition that a series of procedure from the issuance of L/C to the advice is done by SWIFT system. Because perfect e-L/C should be organically connected by SWIFT network and also, the e-L/C business between overseas banks and their customers should be organically linked with each other. The purpose of this paper is contribute to the commercialization of e-L/C distribution system by studying the current status of infrastructure concerned with domestic and overseas electronic payment and future e-payment infrastructure, seeking to be introduced internationally by doing things.

• Journal of Environmental Health Sciences
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• v.36 no.1
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• pp.52-60
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• 2010

High performance liquid chromatography (HPLC) and liquid chromatography mass spectrometry (LC/MS) have been widely used to quantify aflatoxins in food, but these methods are expensive, time-consuming, unsuitable for analysis of the routine screening of large sample numbers and require derivatization and high level techniques to perform. The objective of this study is to detect aflatoxins in a large number of foods by a high efficient analytical system of combined enzyme linked immunosorbent assay (ELISA) for screening and LC/MS/MS for confirmation. The samples spiked individually with aflatoxin $B_1$ (0.5 and 1.0 ng/g) and total aflatoxins (10 ng/g) were analyzed by ELISA and LC/MS/ MS, and the recoveries for ELISA and LC/MS/MS were 71.8~119.2% and 70.8~135.3%, respectively. A total of 378 samples (grains, nuts, soybean and fermented soybean foods, pepper and fermented pepper foods) were purchased from the six major cities in Korea and analyzed by ELISA-LC/MS/MS system. Twenty two (5.8%; peanut: 11, pistachio: 2, walnut: 6, almond: 1, pepper powder: 1, pepper paste: 1) out of 378 samples were screened as aflatoxin B1 positive by ELISA, but, 4 (1.1%; peanut: 2, pistachio:1, pepper powder: 1) out of the 22 samples screened were confirmed as aflatoxins positive at levels of 1.02~52.79 ng/g by LC/MS/MS. ELISA-LC/MS/MS system provides a more rapid, accurate and cost-effective method for the detection of aflatoxins in large number of samples.