• Journal of Convergence for Information Technology
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• v.12 no.3
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• pp.151-157
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• 2022

The purpose of this study was to investigate the frequency characteristics of forced vibration considering the vehicle progress. And the vibration characteristics in frequency domain that occur, when vehicle passes the bump, were analyzed. The responses such as displacement, velocity and acceleration were obtained through numerical analysis, and FFT processing was performed to analyze the frequency response function(FRF) characteristics. In particular, the location of vehicle eigenmodes and external excitation modes was clearly shown and analyzed. In the forced vibration model by external force, the behavior of the eigenmode in power spectrum and real and imaginary parts were also analyzed. The mode characteristics were also analyzed in each FRF. It was approximated by assuming total excitation force by considering the exciting frequency using impulse and sine wave forces, which can give the amplitude and frequencies. The response characteristics of forced oscillations having different mass, damping and stiffness have been systematically discussed.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.2
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• pp.195-201
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• 2014

Body fluid has been studied for diverse fields like Ringer's solutions, artificial joint fluids, cell growth culture media because it plays a crucial role in controlling body temperature and acts as a solvent for diverse metabolite processes in the body and delivery media of mineral, energy source, hormone, signal and drug from and to cell via blood or lymphatic vessel by osmotic pressure or active uptake. Stratum corneum containing extracellular lipids and NMF (natural moisturizing factor) absorbs atmospheric water residing outside of cells and utilize it to hydrate inside of their own. This process is related to skin barrier function. In this study, we conducted the cell viability test with Cell Bio Fluid $Sync^{TM}$, which mimicks body fluids including amino acids, peptides, and monosaccharides to strengthen skin barrier, and the clinical skin improvement test with cosmetics containing Cell Bio Fluid $Sync^{TM}$. In the cell viability test, HaCaT cell was treated with PBS for 3 hours, followed by the treatment of a cell culture medium (DMEM) and isotonic solution (PBS) and Cell Bio Fluid $Sync^{TM}$ for 3 hours each. Then, MTT assay and image analysis were conducted. In the clinical skin improvement test, twenty-one healthy women participated. Participants applied cosmetics containing Cell Bio Fluid $Sync^{TM}$ on their face for a week and evaluated the skin hydration, skin roughness, brightness and evenness. All measurements were conducted after they washed off their face and took a rest under the constant temperature ($22{\pm}2^{\circ}C$) and constant humidity conditions ($50{\pm}5%$) for 20 minutes. All the data were analyzed by SPSS (version 21) software program. Results showed that Cell Bio Fluid $Sync^{TM}$ improved both the cell viability and in vivo skin conditions such as skin hydration, roughness, brightness and evenness.

• Journal of Life Science
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• v.27 no.4
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• pp.383-389
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• 2017

This study intends to analyze the contents of rutin, procyanidin B3, quercetin, kaempferol, known to have antioxidant, anti-inflammatory and anti-carcinogenic effects, among the polyphenol type contained in the grape pruning stem extracts (GPSE), utilizing grape stems being discarded after harvest, measure the effects on the skin moisture, inhibition of skin cell proliferation, anti-inflammatory on the damaged skin of a HR-1 mice induced with UVB, and verify the applicability as a material for functional food and functional cosmetics. The results of verifying the photoprotection effects through the skin proliferation control through of GPSE showed similar result to suncream was achieved at the GPSE concentration of 2,000 mg/kg on the epidermis (p<0.05). The results showed anti-inflammatory effects on all groups applied with GPSE as compared to the control group irradiated with UVB, but at the GPSE concentration of 1,000 mg/kg, a lower COX-2 protein expression at 8%, lower than the 22% of suncream, was observed to achieve an excellent anti-inflammatory effect (p<0.05). The results of this study confirmed the existence of active polyphenol type, such as rutin, kaempferol, querocetin and procyanidin B3, within the GPSE, and GPSE has improvement effects on moisturizing effects, skin proliferation control effect, inflammatory control effect and improvement effects on the skin barrier function through UV ray damage. GPSE is a functional ingredient with a potential for skin protection effects, and has high utilization as an ingredient for functional food and functional cosmetics.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.50 no.2
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• pp.179-192
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• 2024

In this study, six types of natural products, Prunus tomentosa (P. tomentosa), Akebia quinata (A. quinata), Prunus armeniaca (P. armeniaca), Smallanthus sonchifolius (S. sonchifolius), Citrus japonica (C. japonica), and Citrus australasica (C. australasica), were used to verify the effect of improving sleep and skin barriers by stress relief. As a result of the experiment, the production of cortisol, a stress hormone, was significantly inhibited by the P. tomentosa, C. australasica, A. quinata, and C. japonica among the six natural products. In addition, the expression of GAD67, a GABA-producing enzyme involved in sleep regulation, showed a significant increase in P. tomentosa purified water extract and C. australasica 50% ethanol extract, and the extract by each P. tomentosa solvent was found to have the highest total polyphenol content. Based on the results, the P. tomentosa extract with the highest activity was finally selected, and subsequent experiments were conducted. Among each P. tomentosa solvent extract, the DPPH radical scavenging activity was the highest in the 30% ethanol extract, and purified water extract increased GABA production and skin barrier factors filaggrin and claudin-1 expression the highest. HPLC analysis confirmed quercitrin as the main component of P. tomentosa extract, and quercitrin content by extraction solvent was high in the order of 30% ethanol > purified water > 70% ethanol > 50% ethanol. Quercitrin inhibited the production of cortisol in a concentration-dependent manner, significantly increasing GAD67 expression and GABA production, which had been reduced by cortisol. From the results of this study, it has been demonstrated that P. tomentosa can be used as a cosmetic material to help improve sleep and strengthen skin barriers by relieving stress.

• The Journal of Engineering Geology
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• v.23 no.1
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• pp.57-65
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• 2013

We developed a computer program (CDFlow v. 1.0) to design countermeasures against debris flows in natural terrain. The program can predict the probability of landslides occurring in natural terrain and can estimate the zone of damage caused by a debris flow. It can also be used to design the location and size of countermeasures against the debris flow. The program is run using the ArcGIS Engine, which is one of the most well-known Geographic Information System (GIS) tools for developers. The quasi-dynamic wetness index and the infinite slope stability equation were applied to predict landslide probability as a type of slope safety factor. The calculated safety factor was compared with the required safety factor, and areas of high probable potential for landslides were then selected and represented on the digital map. The volume of debris flow was estimated using these areas of high probable potential for landslides and soil depth. The accumulated volume of debris flow can be calculated along the flow channel. To assess the accuracy of the program, it was applied to a real landslide site at Deoksan-ri, Inje-gun, Kangwon-Province, where four debris barriers have been installed in the watershed of the site. The results of soil tests and a field survey indicate that the program has great potential for estimating probable landslide areas and the trajectory of debris flows. Calculation of the capacity volume of existing debris barriers revealed that they had insufficient capacity to store the calculated amount of debris flow. Therefore, this program enables a rational estimation of the optimal location and size of debris barriers.

• Journal of Life Science
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• v.28 no.9
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• pp.1016-1021
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• 2018

Clostridium difficile toxin A causes pseudomembranous colitis. The pathogenesis of toxin A-induced colonic inflammation includes toxin A-dependent epithelial cell apoptosis, resulting in the loss of barrier function provided by epithelial cells against luminal pathogens. Toxin A-dependent epithelial cell apoptosis has been linked to toxin A-induced production of reaction oxygen species and subsequent p38MAPK activation; $p21^{CIP1/WAF1}$ upregulation-dependent cell cycle arrest; cytoskeletal disaggregation; and/or the induction of Fas ligand on epithelial cells. However, the molecular mechanisms underlying toxin A-induced apoptosis remain poorly understood. This study tested whether toxin A could block the Wnt signaling pathway, which is involved in gut epithelial cell proliferation, differentiation and antiapoptotic progression. Toxin A treatment of nontransformed human colonocytes (NCM460) rapidly reduced ${\beta}$-catenin protein, an essential component of the Wnt signaling pathway. Exposure of mouse ileum to toxin A also significantly reduced ${\beta}$-catenin protein levels. MG132 inhibition of proteasome-dependent protein degradation resulted in the recovery of toxin A-mediated reduction of ${\beta}$-catenin, indicating that toxin A may activate intracellular processes, such as $GSK3{\beta}$, to promote degradation of ${\beta}$-catenin. Immunoblot analysis showed that toxin A increased active phosphorylation of $GSK3{\beta}$. Because the Wnt signaling pathway is essential for gut epithelial cell proliferation and anti-apoptotic processes, our results suggest that toxin A-mediated inhibition of the Wnt signaling pathway may be required for maximal toxin A-induced apoptosis of gut epithelial cells.

• Journal of Life Science
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• v.28 no.8
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• pp.885-891
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• 2018

Clostridium difficile (C. difficile) toxin A is known to cause acute gut inflammation in humans and animals by triggering cytoskeletal disorganization in gut epithelial cells. In human colonocytes, toxin A blocks microtubule assembly by directly increasing the enzymatic activity of histone deacetylase-6 (HDAC-6), a tubulin-specific deacetylase, thereby markedly decreasing tubulin acetylation, which is essential for microtubule assembly. Microtubule assembly dysfunction-associated alterations (i.e., toxin A-exposed gut epithelial cells) are believed to trigger barrier dysfunction and gut inflammation downstream. We recently showed that potassium acetate blocked toxin A-induced microtubule disassembly by inhibiting HDAC-6. Herein, we tested whether acetic acid (AA), another small acetyl residue-containing agent, could block toxin A-induced tubulin deacetylation and subsequent microtubule assembly. Our results revealed that AA treatment increased tubulin acetylation and enhanced microtubule assembly in an HT29 human colonocyte cell line. AA also clearly increased tubulin acetylation in murine colonic explants. Interestingly, the AA treatment also alleviated toxin A-induced tubulin deacetylation and microtubule disassembly, and MTT assays revealed that AA reduced toxin A-induced cell toxicity. Collectively, these results suggest that AA can block the ability of toxin A to cause microtubule disassembly-triggered cytoskeletal disorganization by blocking toxin A-mediated deacetylation of tubulin.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.3
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• pp.218-226
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• 2016

Field observations were used to study the characteristics and influence of groundwater level fluctuations on vegetation development on the natural beach of a sandy barrier island, in the Nakdong River estuary. The spatial/temporal fluctuations of the groundwater level and the interactions with the external forces (weather, ocean wave and tide) were analyzed. The results indicated that when it rains the groundwater level rises. During summer, when precipitation intensity is greater than 20 mm/hour, it rose rapidly over 20 cm. Subsequently, it fell gradually during periods of no precipitation. Seasonal characteristics indicated that the groundwater level was high during the summer rainy season and tended to fall in the winter dry season. The time-averaged groundwater level, observed from the four observations over 3 years (2012-2014), was about 1.47 m, higher than mean sea level (M.S.L.). It was shown that the average annual groundwater level rises toward the land rather than showing intertidal patterns observation. Differences in the presence or absence of a coastal sand dunes affected the progress of vegetation. In other words, in environments of saltwater intrusion where the groundwater level varies, dependent on the distance from the shoreline and bottom slope, sand dunes can be provided to affect soil conditions and groundwater, so that vegetation can be grown reliably.

• Journal of the Korean Chemical Society
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• v.40 no.4
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• pp.219-228
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• 1996

An ab initio molecular orbital method has been applied to investigation of molecular properties and equilibrium geometries for hexahydroxybenzene triscarbonate (C9O9) and its analogous cyclic compounds (C9S9, C9O6S3, C9O3S6). In these works, the optimized geometry of each compound has been obtained at HF and MP2 levels. These results have shown that the optimized geometries of these compounds prefer D3h planar structure to C3v bowl structure. Calculations of harmonic vibrational frequencies have been also carried out at HF/3-21G* level to analyze normal modes of these compounds. Bonding characters of these compounds are studied by Mulliken and natural populations obtained at HF/6-31G* level. We have also studied the structures and the populations of C6O6 and C6S6 at HF and MP2 levels which are obtained by pyrolyses of C9O9 and analogous compounds. In addition, the single point calculations have been performed to predict the approximate energy barrier for pyrolysis of each compound.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.91-91
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• 2013

Imagine a world where we could biomanufacture hybrid nanomaterials having atomic-scale resolution over functionality and architecture. Toward this vision, a fundamental challenge in materials science is how to design and synthesize protein-like material that can be fully self-assembled and exhibit information-specific process. In an ongoing effort to extend the fundamental understanding of protein structure to non-natural systems, we have designed a class of short peptides to fold like proteins and assemble into defined nanostructures. In this talk, I will talk about new strategies to drive the self-assembled structures designing sequence of peptide. I will also discuss about the specific interaction between proteins and inorganics that can be used for the development of new hybrid solar energy devices. Splitting water into hydrogen and oxygen is one of the promising pathways for solar to energy convertsion and storage system. The oxygen evolution reaction (OER) has been regarded as a major bottleneck in the overall water splitting process due to the slow transfer rate of four electrons and the high activation energy barrier for O-O bond formation. In nature, there is a water oxidation complex (WOC) in photosystem II (PSII) comprised of the earthabundant elements Mn and Ca. The WOC in photosystem II, in the form of a cubical CaMn4O5 cluster, efficiently catalyzes water oxidation under neutral conditions with extremely low overpotential (~160 mV) and a high TOF number. The cluster is stabilized by a surrounding redox-active peptide ligand, and undergo successive changes in oxidation state by PCET (proton-coupled electron transfer) reaction with the peptide ligand. It is fundamental challenge to achieve a level of structural complexity and functionality that rivals that seen in the cubane Mn4CaO5 cluster and surrounding peptide in nature. In this presentation, I will present a new strategy to mimic the natural photosystem. The approach is based on the atomically defined assembly based on the short redox-active peptide sequences. Additionally, I will show a newly identified manganese based compound that is very close to manganese clusters in photosystem II.