• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.1
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• pp.112-121
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• 2016

AFLS (Adaptive front lighting system) is being applied to improve safety in driving automotive at night. Safe embedded system design for controlling head-lamps is required to improve noise robust ECU hardware and software simultaneously by considering safety requirement of hardware-dependent software under severe environmental noise. In this paper, we propose an adaptive headlight controller with a newly-designed symmetric angle sensor compensator, especially based on the proposed steering-swivel angle lookup table to determine whether the current controlling target is safe. The proposed system includes an additional backup hardware to compare the system status and provides safe swivel-angle management using a controlling algorithm based on the pre-defined lookup table (LUT), which is a symmetric mapping relationship between the requested steering angle and expected swivel angle target. The implemented system model shows that the proposed architecture effectively detects abnormal situations and restores safe status of controlling the light-angle in AFLS operations under severe noisy environment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.65-65
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• 2007

Microstructure and surface roughness of the sensing materials should be improved to use them in advanced sensor applications because the uneven surface roughness degrades the light reflection, pattern resolution, and devices performance. Chemical mechanical polishing (CMP) processing was selected for improving the surface roughness of $CeO_2$ which is one of the well known materials for the oxygen gas sensors. Surface roughness and removal rate of spin coated $CeO_2$ thin films were examined with a change of CMP process parameters such as down force and table speed. The optimized process condition, reflected by the surface roughness with the hillock-free surface as well as the excellent removal rate with the good uniformity, was obtained. The effects of the improved surface roughness on the sensing property of $CeO_2$ thin films were also confirmed. The improved sensitivity of $CeO_2$ thin films for oxygen sensors were obtained after CMP process by the improved surface characteristics. Therefore, we conclude that sensing property of $CeO_2$ thin film is strongly dependent on the surface roughness of $CeO_2$ thin films by using CMP process.

• Macromolecular Research
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• v.15 no.5
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• pp.437-442
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• 2007

Poly(ethylene glycol) methyl ether (PEG)-poly(${\beta}$-amino ester) (PAE) block copolymers were synthesized using a Michael-type step polymerization, and the construction of pH-sensitive polymeric micelles (PM) investigated. The ${\beta}$-amino ester block of the block copolymers functioned as a pH-sensitive moiety as well as a hydrophobic block in relation to the ionization of PAE, while PEG acted as a hydrophilic block, regardless of ionization. The synthesized polymers were characterized using $^1H-NMR$, with their molecular weights measured using gel permeation chromatography. The $pK_b$ values of the pH-sensitive polymers were measured using a titration method. The pH-sensitivity and critical micelle concentration (CMC) of the block copolymers in PBS solution were estimated using fluorescence spectroscopy. The pH dependent micellization behaviors with various bisacrylate esters varied within a narrow pH range. The critical micelle concentration at pH 7.4 decreased from 0.032 to 0.004 mg/mL on increasing the number of methyl group in the bisacrylate from 4 to 10. Also, the particle size of the block copolymer micelles was determined using dynamic light scattering (DLS). The DLS results revealed the micelles had an average size below 100 nm. These pH-sensitive polymeric micelles may be good carriers for the delivery of an anticancer drug.

• Toxicological Research
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• v.33 no.4
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• pp.325-332
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• 2017

3-Bromo-4,5-dihydroxybenzaldehyde (BDB) is a natural bromophenol compound that is most commonly isolated from red algae. The present study was designed to investigate the anti-inflammatory properties of BDB on atopic dermatitis (AD) in mice induced by 2,4-dinitrochlorobenzene (DNCB) and on lipopolysaccharide (LPS)-stimulated murine macrophages. BDB treatment (100 mg/kg) resulted in suppression of the development of AD symptoms compared with the control treatment (induction-only), as demonstrated by reduced immunoglobulin E levels in serum, smaller lymph nodes with reduced thickness and length, a decrease in ear edema, and reduced levels of inflammatory cell infiltration in the ears. In RAW 264.7 murine macrophages, BDB (12.5, 25, 50, and $100{\mu}M$) suppressed the production of interleukin-6, a proinflammatory cytokine, in a dose-dependent manner. BDB also had an inhibitory effect on the phosphorylation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-${\kappa}B$) and signal transducer and activator of transcription 1 (STAT1; Tyr 701), two major signaling molecules involved in cellular inflammation. Taken together, the results show that BDB treatment alleviates inflammatory responses in an atopic dermatitis mouse model and RAW 264.7 macrophages. These results suggest that BDB may be a useful therapeutic strategy for treating conditions involving allergic inflammation such as atopic dermatitis.

• Parasites, Hosts and Diseases
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• v.49 no.3
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• pp.285-290
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• 2011

Naegleria fowleri, a ubiquitous free-living ameba, causes fatal primary amebic meningoencephalitis in humans. N. fowleri trophozoites are known to induce cytopathic changes upon contact with microglial cells, including necrotic and apoptotic cell death and pro-inflammatory cytokine release. In this study, we treated rat microglial cells with amebic lysate to probe contact-independent mechanisms for cytotoxicity, determining through a combination of light microscopy and scanning and transmission electron microscopy whether N. fowleri lysate could effect on both necrosis and apoptosis on microglia in a time- as well as dose-dependent fashion. A $^{51}Cr$ release assay demonstrated pronounced lysate induction of cytotoxicity (71.5%) toward microglial cells by 24 hr after its addition to cultures. In an assay of pro-inflammatory cytokine release, microglial cells treated with N. fowleri lysate produced TNF-${\alpha}$, IL-6, and IL-$1{\beta}$, though generation of the former 2 cytokines was reduced with time, and that of the last increased throughout the experimental period. In summary, N. fowleri lysate exerted strong cytopathic effects on microglial cells, and elicited pro-inflammatory cytokine release as a primary immune response.

• Parasites, Hosts and Diseases
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• v.58 no.2
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• pp.173-179
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• 2020

Leishmaniasis is a prevalent cause of death and animal morbidity in underdeveloped countries of endemic area. However, there is few vaccine and effective drugs. Antimicrobial peptides are involved in the innate immune response in many organisms and are being developed as novel drugs against parasitic infections. In the present study, we synthesized a 5-amino acid peptide REDLK, which mutated the C-terminus of Pseudomonas exotoxin, to identify its effect on the Leishmania tarentolae. Promastigotes were incubated with different concentration of REDLK peptide, and the viability of parasite was assessed using MTT and Trypan blue dye. Morphologic damage of Leishmania was analyzed by light and electron microscopy. Cellular apoptosis was observed using the annexin V-FITC/PI apoptosis detection kit, mitochondrial membrane potential assay kit and flow cytometry. Our results showed that Leishmania tarentolae was susceptible to REDLK in a dose-dependent manner, disrupt the surface membrane integrity and caused parasite apoptosis. In our study, we demonstrated the leishmanicidal activity of an antimicrobial peptide REDLK from Pseudomonas aeruginosa against Leishmania tarentolae in vitro and present a foundation for further research of anti-leishmanial drugs.

• Journal of Life Science
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• v.23 no.2
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• pp.207-212
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• 2013

In this paper, we investigated whether resveratrol could induce the expression of cysteine-rich angiogenic inducer 61 (CYR61), which is a member of the CCN families. We showed that resveratrol up-regulated CYR61 protein expression in three different human colorectal cancer cell lines. In addition, resveratrol induced CYR61 protein expression in a dose- and time-dependent manner in a HCT116 cell line. To investigate the relationship between various biological activities of resveratrol and CYR61 expression, HCT116 cells were incubated with several NSAIDs, antioxidants, or resveratrol. Interestingly, resveratrol only induced CYR61 protein expression. The expression of CYR61 was not related to the presence of p53. A promoter assay revealed that the 786-bp promoter region (-732/+54) contains a regulatory region and that indole-3-carbinol and 6-gingerol could not induce CYR61 expression. In conclusion, our results indicate up-regulation of CYR61 is extremely resveratrol specific. The results can help to shed light on the unique biological function of resveratrol.

• Korean Journal of Ecology and Environment
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• v.42 no.1
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• pp.107-114
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• 2009

We investigated the predation behavior of larval damselfly on Daphnia pulex and D. galeata, and compared the life history and morphological defenses in two Daphnia species against larval damselfly and fish kairomones. Larval damselflies showed size-dependent predation behavior and preyed upon smaller daphnids easily regardless light condition. Overall, small D. galeata juveniles were more vulnerable than D. pulex to the larval damselfly predation. D. pulex displayed life history and morphological changes as the anti-predator defenses against larval damselfly as well as large mouth bass, while D. galeata showed the anti-predator defenses to the large mouth bass. Thus, our results revealed that two Daphnia species exhibits different anti-predator defense strategy to increase survivorship.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.304-304
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• 2010

The study on the catalytic oxidation of carbon monoxide (CO) to carbon dioxide ($CO_2$) using the noble metals has long been the interest subject and the recent progress in nanoscience provides the opportunity to develop new model systems of catalysts in this field. Of the noble metal catalysts, we selected ruthenium (Ru) as metal catalyst due to its unusual catalytic behavior. The size of colloid Ru NPs was controlled by the concentration of Ru precursor and the final reduction temperatures. For catalytic activity of CO oxidation, it was found that the trend is dependent on the size of Ru NPs. In order to explain this trend, the surface oxide layer surrounding the metal core has been suggested as the catalytically active species through several studies. In this poster, we show the influence of surface oxide on Ru NPs on the catalytic activity of CO oxidation using chemical treatments including oxidation, reduction and UV-Ozone surface treatment. The changes occurring to UV-Ozone surface treatment will be characterized with XPS and SEM. The catalytic activity before and after the chemical modification were measured. We discuss the trend of catalytic activity in light of the formation of core-shell type oxide on nanoparticles surfaces.

• Journal of the Korean Society of Food Culture
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• v.34 no.5
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• pp.645-650
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• 2019

Skin plays important roles in protecting the internal organs from the chemical-biological risk factors and ultraviolet light. Exposure to the chemical and biological stimuli has a detrimental effect on skin's structure and physiological regulation. Therefore, much attention has been paid to natural products that show biological activities such as anti-oxidation, anti-aging and anti-bacterial activities. In this study, we investigated the skin-related biological activities of Oenothera lamarckiana aerial part extract. The extract contained 229.35 mg TAE (tannic acid equivalents)/g total polyphenolic compounds and the extract showed relative high antioxidant activity ($SC_{50}$ value: $8.52{\mu}g/mL$). The $IC_{50}$ value against tyrosinase and elastase were 307.94 and $181.51{\mu}g/mL$, respectively. This suggested that O. lamarckiana can be applied to whiten skin and slow the aging of skin. O. lamarckiana extract showed a growth inhibitory effect on Staphylococcu epidermidis (minimum inhibitory concentration: $250{\mu}g/mL$). Interestingly, O. lamarckiana extract showed no inhibitory effect on Pseudomonas aeruginosa on the paper disc assay. Yet the extract inhibited the growth of Pseudomonas aeruginosa on the broth dilution assay in a dose-dependent manners. Taken together, O. lamarckiana could have good potential for development as an additive in the cosmetic industry.