• Journal of Microbiology and Biotechnology
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• v.33 no.1
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• pp.83-95
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• 2023

These days, bacterial detection methods have some limitations in sensitivity, specificity, and multiple detection. To overcome these, novel detection and identification method is necessary to be developed. Recently, NGS panel method has been suggested to screen, detect, and even identify specific foodborne pathogens in one reaction. In this study, new NGS panel primer sets were developed to target 13 specific virulence factor genes from five types of pathogenic Escherichia coli, Listeria monocytogenes, and Salmonella enterica serovar Typhimurium, respectively. Evaluation of the primer sets using singleplex PCR, crosscheck PCR and multiplex PCR revealed high specificity and selectivity without interference of primers or genomic DNAs. Subsequent NGS panel analysis with six artificially contaminated food samples using those primer sets showed that all target genes were multi-detected in one reaction at 10⁸-10⁵ CFU of target strains. However, a few false-positive results were shown at 10⁶-10⁵ CFU. To validate this NGS panel analysis, three sets of qPCR analyses were independently performed with the same contaminated food samples, showing the similar specificity and selectivity for detection and identification. While this NGS panel still has some issues for detection and identification of specific foodborne pathogens, it has much more advantages, especially multiple detection and identification in one reaction, and it could be improved by further optimized NGS panel primer sets and even by application of a new real-time NGS sequencing technology. Therefore, this study suggests the efficiency and usability of NGS panel for rapid determination of origin strain in various foodborne outbreaks in one reaction.

• Korean Chemical Engineering Research
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• v.61 no.2
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• pp.175-188
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• 2023

Global interest in hydrogen energy is increasing as an eco-friendly future energy that can replace fossil fuels. Accordingly, a next-generation hydrogen production technology using microorganisms, nuclear power, etc. is being developed, while a lot of time and effort are still required to overcome the cost of hydrogen production based on fossil fuels. As a way to minimize greenhouse gas emissions in the hydrocarbon-based hydrogen production process, methane direct decomposition technology has recently attracted attention. In order to improve the economic feasibility of the process, the simultaneous production of value-added carbon materials with hydrogen can be one of the most essential aspects. For that purpose, various studies on catalysis related to the quality and yield of high-value carbon materials such as carbon nanotubes (CNTs). In terms of process technology, a number of the research and development of fluidized-bed reactors capable of continuous production and improved gas-solid contact efficiency has been attempted. Recently, methane direct decomposition technology using a fluidized bed has been developed to the extent that it can produce 270 kg/day of hydrogen and 1000 kg/day of carbon. Plus, with the development of catalyst regeneration, separation and recirculation technologies, the process efficiency can be further improved. This review paper investigates the recent development of catalysts and fluidized bed reactor for methane direct pyrolysis to identify the key challenges and opportunities.

• Journal of the Korean Geotechnical Society
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• v.25 no.6
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• pp.17-29
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• 2009

There has been an increase in the investigation of deep sea sediments with a consequent increase in the amount of energy required to undertake these investigations. The geotechnical characteristics of Ulleung Basin sediment are explored by using depressurized specimens following methane production tests carried out on pressured core samples obtained at 2,100 m water depth and 110 m below sea floor. Geotechnical index tests, X-ray diffraction, and scanning electron microscope are conducted to identify the geotechnical index parameters, clay mineralogy, chemical composition, and microstructure of the sediments. Compressibility, and elastic and electromagnetic wave parameters are investigated for two samples by using a multi sensing instrumented oedometer cell. The strength chatracteristics are obtained by the direct shear tests. The dominant clay minerals are mostly kaolinite, illite, chlorite, and calcite. The SEM shows a well-developed flocculated structure of the microfossil. Void ratio, electrical resistivity, real permittivity, conductivity, and shear wave velocity show bi-linear behavior with the effective vertical stress: as the vertical effective stress increases. The friction angle obtained by the direct shear test is about $21^{\circ}$, which is similar to the value observed in the Ulleung Basin sediments. This study shows that the understanding of the behavior acting on the diatomaceous marine sediment is important because it often maintains the useful energy resources such as gas hydrate and so will be the new engineering field in the next generation.

• Journal of Life Science
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• v.33 no.4
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• pp.325-333
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• 2023

This study compared and analyzed the microbial composition and physicochemical characteristics of kimchi (gimjang kimchi) and mukeunji (aged kimchi). Commercial kimchi and mukeunji products were purchased through an online market. After an analysis of physicochemical characteristics, the pH of the mukeunji samples was found to be lower and the acidity higher than in the kimchi samples. There was no significant difference in salinity between kimchi and mukeunji, but the sugar content was higher in the kimchi samples. The phylogenetic diversity index, which incorporates phylogenetic difference between species, was significantly higher in mukeunji than in the kimchi. The most dominant order in both groups was Lactobacillales, but several lactic acid bacteria, such as the Pediococcus and Lactobacillus species, which may be more acid tolerant or more competitive, are relatively predominant in mukeunji. Beta set-significance analysis based on two different distance metric results revealed that microbial distributions of population were different at the statistical confidence level (p<0.001). We investigated the effect of respective species on total microbial community using the LEfSe (linear discriminant analysis effect size) mechanism. According to the results of LEfSe testing, a relatively higher abundance of Weissella kandleri in kimchi and a higher abundance of Pediococcus inopinatus in mukeunji have the greatest influence on the differences in microbial structure between the two groups.

• Journal of Broadcast Engineering
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• v.27 no.1
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• pp.69-79
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• 2022

In this study, a method of generating and utilizing a normal map image used to represent the characteristics of the surface of an image material to improve the classification accuracy of the original material image is proposed. First of all, (1) to generate a normal map that reflects the surface properties of a material in an image, a U-Net with attention-R2 gate as a generator was used, and a Pix2Pix-based method using the generated normal map and the similarity with the original normal map as a reconstruction loss was used. Next, (2) we propose a network that can improve the accuracy of classification of the original material image by applying the previously created normal map image to the attention gate of the classification network. For normal maps generated using Pixar Dataset, the similarity between normal maps corresponding to ground truth is evaluated. In this case, the results of reconstruction loss function applied differently according to the similarity metrics are compared. In addition, for evaluation of material image classification, it was confirmed that the proposed method based on MINC-2500 and FMD datasets and comparative experiments in previous studies could be more accurately distinguished. The method proposed in this paper is expected to be the basis for various image processing and network construction that can identify substances within an image.

• Membrane Journal
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• v.32 no.1
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• pp.43-49
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• 2022

Solid-state supercapacitors with high safety and robust mechanical properties are attracting global attention as next-generation energy storage devices. As an electrode of a supercapacitor, an economical carbon-based electrode is widely used. However, when an aqueous electrolyte is introduced, the charge transfer resistance increases because the interfacial contact between the hydrophobic electrode surface and aqueous electrolyte is not good. In this regard, we propose a method to obtain higher electrochemical performance based on improved interfacial properties by treating the electrode surface with oxygen plasma. The surface hydrophilization induced by the enriched oxygen functionalities was confirmed by the contact angle measurement. As a result, the degree of hydrophilization was easily adjusted by controlling the power and duration of the oxygen plasma treatment. As the electrolyte of the supercapacitor, PVA/H₃PO₄, which is a typical solid-state aqueous electrolyte, was used. Free-standing membranes of PVA/H₃PO₄ electrolyte were prepared and then pressed onto the electrode. The optimal condition was to perform oxygen plasma treatment for 5 seconds with a low power of 15 W, and the energy density of the supercapacitor increased by about 8%.

• Molecules and Cells
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• v.45 no.3
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• pp.134-147
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• 2022

The anti-oxidant enzyme heme oxygenase-1 (HO-1) is known to exert anti-inflammatory effects. From a library of pyrazolo[3,4-d]pyrimidines, we identified a novel compound KKC080096 that upregulated HO-1 at the mRNA and protein levels in microglial BV-2 cells. KKC080096 exhibited anti-inflammatory effects via suppressing nitric oxide, interleukin1β (IL-1β), and iNOS production in lipopolysaccharide (LPS)-challenged cells. It inhibited the phosphorylation of IKK and MAP kinases (p38, JNK, ERK), which trigger inflammatory signaling, and whose activities are inhibited by HO-1. Further, KKC080096 upregulated anti-inflammatory marker (Arg1, YM1, CD206, IL-10, transforming growth factor-β [TGF-β]) expression. In 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridinetreated mice, KKC080096 lowered microglial activation, protected the nigral dopaminergic neurons, and nigral damage-associated motor deficits. Next, we elucidated the mechanisms by which KKC080096 upregulated HO-1. KKC080096 induced the phosphorylation of AMPK and its known upstream kinases LKB1 and CaMKKbeta, and pharmacological inhibition of AMPK activity reduced the effects of KKC080096 on HO-1 expression and LPS-induced NO generation, suggesting that KKC080096-induced HO-1 upregulation involves LKB1/AMPK and CaMKKbeta/AMPK pathway activation. Further, KKC080096 caused an increase in cellular Nrf2 level, bound to Keap1 (Nrf2 inhibitor protein) with high affinity, and blocked Keap1-Nrf2 interaction. This Nrf2 activation resulted in concurrent induction of HO-1 and other Nrf2-targeted antioxidant enzymes in BV-2 and in dopaminergic CATH.a cells. These results indicate that KKC080096 is a potential therapeutic for oxidative stress-and inflammation-related neurodegenerative disorders such as Parkinson's disease.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.4
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• pp.413-417
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• 2023

Gallium Oxide (Ga₂O₃) is preferred as a material for next generation power semiconductors. The Ga₂O₃ should solve the disadvantages of low thermal resistance characteristics and difficulty in forming an inversion layer through p-type ion implantation. However, Ga₂O₃ is difficult to inject p-type ions, so it is being studied in a heterojunction structure using p-type oxides, such as NiO, SnO, and Cu₂O. Research the lateral-type FET structure of NiO/Ga₂O₃ heterojunction under the Gate contact using the Sentaurus TCAD simulation. At this time, the VG-ID and VD-ID curves were identified by the thickness of the Epi-region (channel) and the doping concentration of NiO of 1×10¹⁷ to 1×10¹⁹ cm-3. The increase in Epi region thickness has a lower threshold voltage from -4.4 V to -9.3 V at I_D = 1×10^-8 mA/mm, as current does not flow only when the depletion of the PN junction extends to the Epi/Sub interface. As an increase of NiO doping concentration, increases the depletion area in Ga₂O₃ region and a high electric field distribution on PN junction, and thus the breakdown voltage increases from 512 V to 636 V at I_D =1×10^-3 A/mm.

• Journal of Life Science
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• v.33 no.6
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• pp.481-489
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• 2023

The taste and quality of soy sauce, a fermented liquid condiment, is greatly influenced by microbial metabolism during fermentation. To investigate the microbiological characteristics of ganjang during the initial fermentation process, we prepared meju (fermented soybean) blocks fermented with starter cultures and solar salts and analyzed the microbial community quantitively using 16S rRNA gene profiling from ganjang that had been fermented over a five-week period. The ganjang samples were collected and analyzed after soaking for week one (1W), three (3W), and five (5W) weeks. We found that Halomonadaceae was significantly higher in the 1W group (89.83%) than the 3W and 5W groups (14.46%, and 13.78%, respectively). At a species level, Chromohalobacter beijerinckii and Chromohalobacter canadensis were the dominant species in the 1W group but several taxa such as Bacillus subtilis, Pediococcus acidilactici, and Enterococcus faecalis were more abundant in the 3W and 5W groups. Pearson correlation analysis of the relative abundance of the bacteria showed a negative correlation between Chromohalobacter and two bacterial genera Bacillus and Enterococcus. Beta-diversity showed a statistical distinction between the 1W and the 3W and 5W groups, while no significance was evident between the 3W and 5W groups. Linear discriminant effect size analysis was used to identify biomarkers and significant differences in the relative abundance of several halophilic bacteria, Bacillus sp. and lactic acid bacteria at 1W, 3W, and 5W, recpectively, which indicates the important role of the bacterial community at these time points.

• Journal of Christian Education in Korea
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• v.74
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• pp.57-80
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• 2023

The purpose of this study is to review the practicality of Christian education for sustainable development in a rapidly changing world. The first part of this study identify the concept, meaning, and direction of implementation of "Sustainable Development," which has been studied and published around UNESCO since the early 1980s, and present practical strategies for the sustainable development of Christian education. This study chronologically selected five major reports published by UNESCO--"Our Common Future"(1987), "Agenda 21"(1992), "UN Decade of Education for Sustainable Development 2005-2014"(2002), "Roadmap for Implementing the Global Action Programme for Education for Sustainable Development 2015-2019"(2014) and "Education for Sustainable Development 2030"(2020)--and examined the concept and meaning of "Sustainable Development"(SD). At the same time, in relation to "Education for Sustainable Development"(ESD), the occurrence, change, and implementation method of "Sustainable Development Goals"(SDGs) were examined and presented. This study derived three Christian educational implications necessary to properly establish the next generation of faith, based on a leadership development strategy using the concept of sustainable development, For the sustainability of Christian education, the foundation of education based on the correct biblical interpretation of cultural mandate is first examined, and then the need for curriculum development and class design is proposed using various types of indicators and educational modules. Finally, specific practices for the development of educational leadership to revitalize Christian education are presented through a multi-dimensional approach.