• Molecules and Cells
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• 제38권8호
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• pp.729-733
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• 2015

C. elegans has two functional peroxidasins (PXN), PXN-1 and PXN-2. PXN-2 is essential to consolidate the extracellular matrix during development and is suggested to interact with PXN-1 antagonistically. pxn-1 is involved in neuronal development and possibly maintenance; therefore, we investigated the relationship between pxn-1 and pxn-2 in neuronal development and in aging. During neuronal development, defects caused by pxn-1 overexpression were suppressed by overexpression of both pxn-1 and pxn-2. In neuronal aging process, pxn-1 mutants showed less age-related neuronal defects, such as neuronal outgrowth, neuronal wavy processes, and enhanced short-term memory performance. In addition, pxn-2 overexpressing animals retained an intact neuronal morphology when compared with age-matched controls. Consistent with these results, overexpression of both pxn-1 and pxn-2 restored the severe neuronal defects present with pxn-1 overexpression. These results implied that there is a negative relationship between pxn-1 and pxn-2 via pxn-1 regulating pxn-2. Therefore, pxn-1 may function in neuronal development and age-related neuronal maintenance through pxn-2.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 한국지진공학회 2003년도 춘계 학술발표회논문집
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• pp.329-336
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• 2003

The box system that is composed only of reinforced concrete walls and slabs are adopted on many high-rise apartment buildings recently constructed in Korea. And the framed structure with shear wall core that can effectively resist horizontal forces is frequently adopted for the structural system for high-rise building structures. In these structures, a shear wall may have one or more openings for functional reasons. It is necessary to use subdivided finite elements for accurate analysis of the shear wall with openings. But it would take significant amount of computational time and memory if the entire building structure is subdivided into a finer mesh. An efficient analysis method that can be used regardless of the number, size and location of openings is proposed in this study. The analysis method uses super element, substructure, matrix condensation technique and fictitious beam technique. Three-dimensional analyses of the box system and the framed structure with shear wall core having various types of openings were peformed to verify the efficiency of the proposed method. It was confirmed that the proposed method have outstanding accuracy with drastically reduced time and computer memory from the analyses of example structures.

• Journal of Industrial and Engineering Chemistry
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• 제68권
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• pp.387-392
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• 2018

Various technical approaches and concepts have been proposed to develop conductive super-hydrophobic (SH) surfaces. However, most of these approaches are not usable in practical applications because of insufficient adhesion and cost issues. Additionally, durability and uniformity issues are still in need of improvement. The goal of this research is to produce a large-area conductive SH surface with improved adhesion performance and uniformity. To this end, carbon nanotubes (CNT) with a high aspect ratio and elastomeric polymer were utilized as a conductive filler and matrix, respectively, to form a coating layer. Additionally, nanoscale silica particles were utilized for stable implementation of the conductive SH surface. To improve the adhesion properties between the SH coating layer and substrate, pretreatment of the substrate was conducted by utilizing both wet and dry etching processes to create specific organic functional groups on the substrate. Following pretreatment of the surface, a zirco-aluminate coupling agent was utilized to enhance adhesion properties between the substrate and the SH coating layer. Raman spectroscopy revealed that adhesion was greatly improved by the formation of a chemical bond between the substrate and the SH coating layer at an optimal coupling agent concentration. The developed conductive SH coating attained a high electromagnetic interference (EMI) shielding effectiveness, which is advantageous in self-cleaning EMI shielding applications.

• Food Science and Biotechnology
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• 제27권6호
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• pp.1811-1821
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• 2018

Obesity is generally caused by quantitative changes in adipocyte differentiation and fat metabolism. Only a few studies have been determined the effect of red beans extract on obesity and plasma cholesterol concentration. We have been studied the functional activities of red-bean extracts including anti-oxidative effect against DNA and cell damages. Histological study including micro CT analysis showed that the accumulation of fat in hepatocytes and intestines was significantly decreased in red bean extract treated group. In addition, plasma cholesterol and triglyceride levels were decreased in blood samples. In addition, it was confirmed that the red bean extract inhibited the expression of $PPAR{\gamma}$, Fabp4 and RETN genes, which regulate total adipocyte differentiation and lipid metabolism. Red bean extract inhibits the expressions of transcription factors associated with adipocyte differentiation in a dose-dependent manner, thereby inhibiting fat accumulation and decreasing blood lipid levels in obese mice induced by high fat diet.

• Journal of Powder Materials
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• 제26권5호
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• pp.383-388
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• 2019

To improve the mechanical properties of aluminum, graphene has been used as a reinforcing material, yielding graphene-reinforced aluminum matrix composites (GRAMCs). Dispersion of graphene materials is an important factor that affects the properties of GRAMCs, which are mainly manufactured by mechanical mixing methods such as ball milling. However, the use of only mechanical mixing process is limited to achieve homogeneous dispersion of graphene. To overcome this problem, in this study, we have prepared composite materials by coating aluminum particles with graphene by a self-assembly reaction using poly vinylalcohol and ethylene diamine as coupling agents. The scanning electron microscopy and Fourier-transform infrared spectroscopy results confirm the coating of graphene on the Al surface. Bulk density of the sintered composites by spark plasma sintering achieved a relative density of over 99% up to 0.5 wt.% graphene oxide content.

• Corrosion Science and Technology
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• 제18권5호
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• pp.168-174
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• 2019

The sol-gel methodology has been applied successfully in the synthesis of a novel hybrid coating based on dimethoxymethyl-n-octadecylsilane precursor. The newly synthesized parent coating was functionalized further with two commercially-available corrosion-inhibitive pigments Moly-$white^{(R)}$ 101-ED and Hfucophos $Zapp^{(R)}$, applied to mild steel panels, and immersed continuously in 3.5% NaCl electrolytic solution for 288 h. The corrosion protection performance of the prepared functional coatings was evaluated using electrochemical impedance spectroscopy (EIS) and DC polarization techniques. An enhancement in the barrier properties has been revealed from the electrochemical characterization data of the hybrid films, in comparison with untreated mild steel substrates following long-term immersion in 3.5% NaCl. The corrosion resistance properties of the newly developed coatings over mild steel substrates found to be largely dependent on the type of the loaded inhibitive pigment in which the Moly-white inhibitor has a positive impact on the corrosion protection performance of the parent coating, while an opposite behavior was observed upon mixing the base polymeric matrix with the commercially-available Zapp corrosion inhibitor.

• Macromolecular Research
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• 제16권3호
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• pp.261-266
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• 2008

A variety of end-functionalized polymers were grafted spontaneously onto multi-walled carbon nano-tubes (MWNTs) using a solution mixing process. The end-functional groups of the polymers underwent noncovalent grafting to the defect sites at the surface of the purified MWNTs through zwitterionic interaction or hydrogen bonding. The physically grafted polymers including polystyrene (PS), poly(methyl methacrylate) (PMMA), polyethylene oxide (PEO), and polydimethylsiloxane (PDMS) provided sufficient compatibility with an organic solvent or polymer matrix, such that the nanotubes could be finely dispersed in various organic media. This approach is universally applicable to a broad range of polymer-solvent pairs, ensuring highly dispersed carbon nanotubes through simple solution mixing.

• Environmental Engineering Research
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• 제23권4호
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• pp.420-429
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• 2018

Soil stabilization is a soil remediation technique that reduces the mobility of heavy metals in soils. Although it is a well-established technique, it is nonetheless essential to perform a follow-up chemical assessment via a leaching test to evaluate the immobilization of heavy metals in the soil matrix. Unfortunately, a standard chemical assessment is not sufficient for evaluation of the biological functional state of stabilized soils slated for agricultural use. Therefore, it is useful to employ a pyrosequencing-based microbial community analysis for the purpose. In this study, a recently stabilized site in the proximity of an exhausted mine was analyzed for bacterial diversity, richness, and relative abundance as well as the effect of environmental factors. Based on the Shannon and Chao1 indices and rarefaction curves, the results showed that the stabilized layer exhibited lower bacterial diversity than control soils. The prevalence of dominant bacterial populations was examined in a hierarchical manner. Relatively high abundances of Proteobacteria and Methylobacter tundripaludum were observed in the stabilized soil. In particular, there was substantial abundance of the Methylobacter genus, which is known for its association with heavy metal contamination. The study demonstrated the efficacy of (micro)biological assessment for aiding in the understanding and post-management of stabilized soils.

• The Journal of the Korea Contents Association
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• 제19권2호
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• pp.469-476
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• 2019

Robotic motion is designed by the rotation and the translation of multiple joint coordinates in a three-dimensional space. Joint coordinates are generally modeled by homogeneous transform matrix. However, the complexity of three dimensional motions prefers the visualization methods based on simulation environments in which models and generated motions work properly. Many simulation environments have the limitations of usability and functional extension from platform dependency and interpretation of predefined commands. This paper proposes the web-based three dimensional simulation environment toward high user accessibility. Also, it covers the small size web server that is linked with Python script. The non linearities of robot control apply to verify the computing efficiency, the process management, and the extendability of user scripts.

• Journal of Microbiology and Biotechnology
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• 제31권8호
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• pp.1175-1182
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• 2021

We investigated the effect of bovine lactoferricin (Lfcin-B), a peptide derived from bovine lactoferrin, on activation of intestinal epithelial cells in IEC-6 intestinal cell, and protection against in vivo rotavirus (RV) infection. Treatment with Lfcin-B significantly enhanced the growth of IEC-6 cells and increased their capacity for attachment and spreading in culture plates. Also, Lfcin-B synergistically augmented the binding of IEC-6 cells to laminin, a component of the extracellular matrix (ECM). In the analysis of the intracellular mechanism related to Lfcin-B-induced activation of IEC-6 cells, this peptide upregulated tyrosine-dependent phosphorylation of focal adhesion kinase (FAK) and paxillin, which are intracellular proteins associated with cell adhesion, spreading, and signal transduction during cell activation. An experiment using synthetic peptides with various sequences of amino acids revealed that a sequence of 9 amino acids (FKCRRWQWR) corresponding to 17-25 of the N-terminus of Lfcin-B is responsible for the epithelial cell activation. In an in vivo experiment, treatment with Lfcin-B one day before RV infection effectively prevented RV-induced diarrhea and significantly reduced RV titers in the bowels of infected mice. These results suggest that Lfcin-B plays meaningful roles in the maintenance and repair of intestinal mucosal tissues, as well as in protecting against intestinal infection by RV. Collectively, Lfcin-B is a promising candidate with potential applications in drugs or functional foods beneficial for intestinal health and mucosal immunity.