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김형목,허영무,양대호,서대교 기계기술연구소 1999 성균관대학교 논문집 기계기술편 Vol.1 No.1
This paper describes experimental investigation on the forming limit for mash-seam welded sheets. The uniaxial tensile test was conducted to evaluate the mechanical properties of weld bead. Experimental forming limit diagrams were investigated for the different thicknesses and properties of welded sheets.
Heo Young Mok,Lee Dong-Geol,Mun Seyoung,Kim Minji,Baek Chaeyun,Lee Haeun,Yun Seok Kyun,Kang Seunghyun,Han Kyudong 한국유전학회 2024 Genes & Genomics Vol.46 No.1
Background The skin microbiome, a diverse community of microorganisms, plays a crucial role in maintaining skin health. Among these microorganisms, the gram-positive bacterium Micrococcus luteus exhibits potential for promoting skin health. This study focuses on postbiotics derived from M. luteus YM-4, a strain isolated from human skin. Objective Our objective is to explore the beneficial effects of YM-4 culture filtrate on dermatological health, including enhancing barrier function, modulating immune response, and aiding recovery from environmental damage. Methods The effects of the YM-4 culture filtrate were tested on human keratinocytes and fibroblasts under various conditions using real-time PCR for gene expression analysis and fibroblast migration assays. A dehydration-simulated model was employed to prepare RNA-Seq samples from HaCaT cells treated with the YM-4 culture filtrate. Differentially expressed genes were identified and functionally classified through k-means clustering, gene ontology terms enrichment analyses, and protein-protein interactions mapping. Results The YM-4 culture filtrate enhanced the expression of genes involved in skin hydration, hyaluronic acid synthesis, barrier function, and cell proliferation. It also reduced inflammation markers in keratinocytes and fibroblasts under stress conditions. It mitigated UVB-induced collagen degradation while promoted collagen synthesis, suggesting anti-aging properties, and accelerated wound healing processes by promoting cell proliferation and migration. RNA sequencing analysis revealed that the YM-4 culture filtrate could reverse dehydration-induced transcriptional changes towards a state similar to untreated cells. Conclusion M. luteus YM-4 culture filtrate exhibits significant therapeutic potential for dermatological applications. Background The skin microbiome, a diverse community of microorganisms, plays a crucial role in maintaining skin health. Among these microorganisms, the gram-positive bacterium Micrococcus luteus exhibits potential for promoting skin health. This study focuses on postbiotics derived from M. luteus YM-4, a strain isolated from human skin. Objective Our objective is to explore the beneficial effects of YM-4 culture filtrate on dermatological health, including enhancing barrier function, modulating immune response, and aiding recovery from environmental damage. Methods The effects of the YM-4 culture filtrate were tested on human keratinocytes and fibroblasts under various conditions using real-time PCR for gene expression analysis and fibroblast migration assays. A dehydration-simulated model was employed to prepare RNA-Seq samples from HaCaT cells treated with the YM-4 culture filtrate. Differentially expressed genes were identified and functionally classified through k-means clustering, gene ontology terms enrichment analyses, and protein-protein interactions mapping. Results The YM-4 culture filtrate enhanced the expression of genes involved in skin hydration, hyaluronic acid synthesis, barrier function, and cell proliferation. It also reduced inflammation markers in keratinocytes and fibroblasts under stress conditions. It mitigated UVB-induced collagen degradation while promoted collagen synthesis, suggesting anti-aging properties, and accelerated wound healing processes by promoting cell proliferation and migration. RNA sequencing analysis revealed that the YM-4 culture filtrate could reverse dehydration-induced transcriptional changes towards a state similar to untreated cells. Conclusion M. luteus YM-4 culture filtrate exhibits significant therapeutic potential for dermatological applications.
Investigation of Filamentous Fungi Producing Safe, Functional Water-Soluble Pigments
( Young Mok Heo ),( Kyeongwon Kim ),( Sun Lul Kwon ),( Joorim Na ),( Hanbyul Lee ),( Seokyoon Jang ),( Chul Hwan Kim ),( Jinho Jung ),( Jae-jin Kim ) 한국균학회 2018 Mycobiology Vol.46 No.3
The production of water-soluble pigments by fungal strains indigenous to South Korea was investigated to find those that are highly productive in submerged culture. Among 113 candidates, 34 strains that colored the inoculated potato dextrose agar medium were selected. They were cultured in potato dextrose broth and extracted with ethanol. The productivity, functionality (radical-scavenging activities), and color information (CIELAB values) of the pigment extracts were measured. Five species produced intense yellowish pigments, and two produced intense reddish pigments that ranked the highest in terms of absorbance units produced per day. The pigment extracts of Penicillium miczynskii, Sanghuangporus baumii, Trichoderma sp. 1, and Trichoderma afroharzianum exhibited high radical-scavenging activity. However, the S. baumii extract showed moderate toxicity in the acute toxicity test, which limits the industrial application of this pigment. In conclusion, P. miczynskii KUC1721, Trichoderma sp. 1 KUC1716, and T. afroharzianum KUC21213 were the best fungal candidates to be industrial producers of safe, functional water-soluble pigments.
Heo, Young Mok,Lee, Hanbyul,Lee, Changsu,Kang, Juwon,Ahn, Joon-Woo,Lee, Young Min,Kang, Kyu-Young,Choi, Yoon-E,Kim, Jae-Jin Elsevier 2017 Algal research Vol.27 No.-
<P><B>Abstract</B></P> <P>To examine the possibility of better utilizing <I>Chlorella vulgaris</I> biomass including its carbohydrate as well as lipid contents, it was investigated whether cell disruption for lipid extraction could render the remaining microalgal residue (MR) suitable for enzymatic saccharification, possibly due to the disruption of cell wall structures. The <I>C. vulgaris</I> biomass was subjected to lipid extraction with different cell disruption methods (autoclaving, microwave irradiation, osmotic shock, and sonication), and recovered MRs were hydrolyzed using an enzyme produced from <I>Trichoderma koningiopsis</I> KUC21269 in this study. The enzyme was produced on-site with a highly simplified medium of barley straw, an agricultural byproduct. As a result, the saccharification rate of MR treated with microwave was more than twice that of the control group, and microwave irradiation appeared to be a promising method for both lipid extraction and subsequent saccharification. Our results suggested that both lipids and carbohydrates in <I>C. vulgaris</I> can be utilized by applying proper cell disruption method and a fungal enzyme produced on-site using an agricultural byproduct, respectively. This study revealed the high potential of <I>C. vulgaris</I> as an integrated bio-resource for both lipids and glucose, which can be converted to biodiesel and bioethanol, providing clues for overcoming hurdles in economically feasible biofuel production using microalgae.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Both lipids and glucose in <I>C. vulgaris</I> could be obtained with a single treatment. </LI> <LI> Cell disruption for lipid extraction could also damage cell wall structures. </LI> <LI> Lipid-extracted residues were hydrolyzed using a fungal enzyme produced on-site. </LI> <LI> Saccharification rate was more than doubled by microwave irradiation. </LI> <LI> Microwave irradiation enhanced the bioaccessibility of cellulose in the cell walls. </LI> </UL> </P>
Lee, Young Min,Lee, Hanbyul,Heo, Young Mok,Hong, Joo-Hyun,Jang, Seokyoon,Kang, Kyu-Young,Kim, Jae-Jin Walter de Gruyter und Co 2017 Holzforschung Vol.71 No.5
<P><B>Abstract</B></P><P>The genus<I>Aureobasidium</I>is wellknown as a wood-staining mold and as a black yeast-like fungi, which produces mainly dark spores or pigmented hyphae within the wood cell lumens. Nevertheless, few studies are dedicated to wood-colonizing<I>Aureobasidium</I>species and little is known about the wood degradation patterns of this genus. In the present study, four<I>Aureobasidium</I>species, including<I>Aureobasidium melanogenum</I>,<I>Aureobasidium leucospermi</I>,<I>Aureobasidium pullulans</I>, and an unknown<I>Aureobasidium</I>sp., were isolated and identified based on phylogenetic analysis.<I>A. melanogenum</I>and<I>A</I>.<I>leucospermi</I>were observed for the first time in Korea. The degradation pattern of Douglas-fir by<I>Aureobasidium</I>was observed for the first time by scanning electron microscopy (SEM). All tested<I>Aureobasidium</I>species except an unknown<I>Aureobasidium</I>sp. revealed soft-rot Type ΙΙ (erosion) in sapwood pine.</P>
Role of Additives on the Performance of CsPbI<sub>3</sub> Solar Cells
Heo, Do Yeon,Han, Sang Mok,Woo, Nam Sub,Kim, Young Ju,Kim, Tae-Yoon,Luo, Zhengtang,Kim, Soo Young American Chemical Society 2018 The Journal of Physical Chemistry Part C Vol.122 No.28
<P>The role of additives in the performance of CsPbI<SUB>3</SUB> perovskite solar cells (PSCs) was investigated. Different kinds of cations and anions were used as additives in a <I>N,N</I>-dimethylformamide (DMF) solution containing CsI and PbI<SUB>2</SUB> (1:1 molar ratio). These include HI, HBr, HCl, NH<SUB>4</SUB>I, NH<SUB>4</SUB>Br, and NH<SUB>4</SUB>Cl. Additive cations (H<SUP>+</SUP> and NH<SUB>4</SUB><SUP>+</SUP>) as well as halide ions (I<SUP>-</SUP>, Br<SUP>-</SUP>, and Cl<SUP>-</SUP>) are important for the properties of PSCs. Especially, the addition of iodine ion showed good characteristics compared to Br<SUP>-</SUP> and Cl<SUP>-</SUP>. Among the CsPbI<SUB>3</SUB> layers prepared with different kinds of additives and annealed at different temperatures, the X-ray diffraction peaks of CsPbI<SUB>3</SUB> were clearly found at 14° and 28° for the sample annealed at 150 °C with 50 μL of HI, suggesting the formation of a cubic structure at the low temperature of 150 °C. The field emission scanning electron microscopy images indicate that the surface of the perovskite layer with hydrogen halide additive (“H<SUP>+”</SUP>-based additive) is more uniform than that with ammonium additive. The roughness profiles determined by atomic force microscopy indicate that the CsPbI<SUB>3</SUB> film with HI additive shows the least roughness among the samples with H<SUP>+</SUP>-based additives. Therefore, the best power conversion efficiency (PCE) of 4.72% is obtained for CsPbI<SUB>3</SUB> PSCs annealed at 150 °C with HI (50 μL). The H<SUP>+</SUP>-based additives seem to react with PbI<SUB>2</SUB> in DMF solution, increasing the solubility of PbI<SUB>2</SUB> and thus lowering the processing temperature. Furthermore, the PCE of CH<SUB>3</SUB>NH<SUB>3</SUB>PbI<SUB>3-<I>x</I></SUB>Cl<SUB><I>x</I></SUB> PSCs decreased from 7.45 to 0.23%, whereas that of CsPbI<SUB>3</SUB> PSCs with 50 μL of HI only decreased from 3.55 to 2.78% after exposing the samples to air for 3 h. These results indicate that H<SUP>+</SUP>-based additives, especially HI, have more impact on the CsPbI<SUB>3</SUB> PSCs in terms of lowering the processing temperature and improving the performance.</P> [FIG OMISSION]</BR>