• 한국분무공학회지
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• 제23권2호
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• pp.58-65
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• 2018

An analytic strategy to control the variable valve actuation applied to two intake valves (flow port intake valve and swirl port intake valve) was performed in this study. we considered the variation in phasing of intake valve profiles by using the Cam-in-Cam technology. The analytic model was implemented in the GT-Power simulation program and analyzed the result of regulated emissions such as, NOx and Soot, especially with IMEP characteristics. Namely, we meticulously investigated the sources of having effect on the amount of NOx and soot formation under the test conditions with retard timing of both flow port and swirl port intake valves for decreasing the opening duration by 35CAD. Also, we analyzed the effect of incylinder pressure and temperature with NOx variations and in-cylinder pressure and temperature on NOx variations and normalized turbulent intensity. Through this analysis, some useful results on the combustion and flow characteristics of the swirl port and flow port control of the intake valve were obtained by this study.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1346-1351
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• 2004

This study is concerned with the thermal analysis during the cool-down period of 135,000 $m^3$ class GT-96 membrane type LNG carrier under IMO design condition. The cool-down is performed to cool the insulation wall and the natural gas in cargo tank for six hours to avoid the thermal shock at the start of loading of $-163^{\circ}C$ LNG. During the cool-down period, the spraying rate for the NG cooling decreases as the temperature of NG falls clown from $-40^{\circ}C$ to $-130^{\circ}C$ and the spraying rate for the insulation wall cooling increases as the temperature gradient of the insulation wall is large. It was confirmed that there existed the largest temperature decrease at the 1 st barrier and 1st insulation, which are among the insulation wall, especially in the top side of the insulation wall. By the 3-D numerical calculation about the cargo tank and the cofferdam during the cool-down period, the temperature variation in hulls and insulations is precisely predicted.

• 대한기계학회논문집B
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• 제34권10호
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• pp.907-916
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• 2010

고온형 연료전지인 MCFC 발전시스템에 가스터빈, 유기매체 랜킨 사이클, 순산소 연소 사이클 등 다양한 하부 사이클을 추가한 통합시스템들의 성능을 비교 해석하였다. MCFC 시스템의 성능과 운전조건을 바탕으로 하여 각 추가 시스템의 주요 설계 변수 변화에 따른 통합시스템의 성능 변화를 해석하였고 이로부터 각 시스템의 최적 성능을 도출하였다. 각 시스템을 비교하여 MCFC와 최적의 결합을 나타내는 시스템을 분석하였는데, MCFC/OXY 시스템이 MCFC 단독 시스템에 비하여 가장 큰 출력 증가를 나타내었으며, MCFC/GT 시스템의 효율 증가가 가장 큰 것으로 나타났다.

• Journal of Microbiology and Biotechnology
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• 제29권10호
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• pp.1553-1560
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• 2019

In a previous study, the antimicrobial peptides extracted from Lactobacillus plantarum UTNGt2 of wild-type fruits of Theobroma grandiflorum (Amazon) were characterized. This study aimed to investigate the antimicrobial mechanisms of peptides in vitro and its protective effect on fresh tomatoes. The addition of partially purified Gt2 peptides to the E. coli suspension cells at the exponential ($OD_{605}=0.7$) growth phase resulted in a decrease with 1.67 (log10) order of magnitude compared to the control without peptide. A marginal event (< 1 log10 difference) was recorded against Salmonella, while no effect was observed when combined with EDTA, suggesting that the presence of a chelating agent interfered with the antimicrobial activity. The Gt2 peptides disrupted the membrane of E. coli, causing the release of ${\beta}$-galactosidase and leakage of DNA/RNA molecules followed by cell death, revealing a bacteriolytic mode of action. The tomatoes fruits coated with Gt2 peptides showed growth inhibition of the artificially inoculated Salmonella cocktail, demonstrating their preservative potential.

• 대한치과교정학회지
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• 제49권1호
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• pp.32-40
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• 2019

Objective: Precise identification of landmarks on posteroanterior (PA) cephalograms is necessary when evaluating lateral problems such as facial asymmetry. The aim of the present study was to investigate whether the use of lateral (LA) cephalograms can reduce errors in landmark identification on PA cephalograms. Methods: Five examiners identified 16 landmarks (Cg, N, ANS, GT, Me, RO, Lo, FM, Z, Or, Zyg, Cd, NC, Ms, M, and Ag) on 32 PA cephalograms with and without LA cephalograms at the same time. The positions of the landmarks were recorded and saved in the horizontal and vertical direction. The mean errors and standard deviation of landmarks location according to the use of LA cephalograms were compared for each landmark. Results: Relatively small errors were found for ANS, Me, Ms, and Ag, while relatively large errors were found for N, GT, Z, Or, and Cd. No significant difference was found between the horizontal and vertical errors for Z and Or, while large vertical errors were found for N, GT, and Cd. The value of identification error was lower when the landmarks were identified using LA cephalograms. Statistically significant error reductions were found at N and Cd with LA cephalograms, especially in the vertical direction. Conclusions: The use of LA cephalograms during identification of landmarks on PA cephalograms could help reduce identification errors.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2022년도 추계학술대회
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• pp.162-163
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• 2022

Maritime transportation is going to transfer to alternative fuels as a result of the worldwide demands toward decarbonization and tougher maritime emissions regulations. Methanol is considered as a potential marine fuel, which has the ability to reduce SOx and CO₂ emissions, reduce climate change effects, and achieve the objective of green shipping. This work proposes and combines the innovative combination system of direct methanol solid oxide fuel cells (SOFC), proton exchange membrane fuel cells (PEMFC), gas turbines (GT), and organic Rankine cycles (ORC) for maritime vessels. The system's primary power source is the SOFC, while the GT and PEMFC use the waste heat from the SOFC to generate useful power and improve the system's ability to use waste heat. Each component's thermodynamics model and the combined system's model are established and examined. The multigeneration system's energy and exergy efficiency are 76.2% and 30.3%, respectively. When compared to a SOFC stand-alone system, the energy efficiency of the GT and PEMFC system is increased by 19.2%. The use of PEMFC linked SOFC has significant efficiency when a ship is being started or maneuvered and a quick response from the power and propulsion plant is required.

• Asian Pacific Journal of Cancer Prevention
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• 제15권11호
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• pp.4617-4622
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• 2014

Background: Several studies have previously focused on associations between the (GT)n repeat polymorphism of the heme oxygenase-1 (HO-1) gene promoter region and risk of cancers, but results are complex. We conducted the present meta-analysis to integrate relevant findings and evaluate the association between HO-1(GT)n repeat polymorphism and cancer susceptibility. Materials and Methods: Published literature was retrieved from the PubMed/MEDLINE, EMBASE and ISI Web of Science databases before November 2013. For all alleles and genogypes, odds ratios were pooled to assess the strength of the associations using either fixed-effects or random-effects models according to heterogeneity. Subgroup analysis was conducted according to ethnicity and histopathology. Results: A total of 10 studies involving 2,367 cases and 2,870 controls were identified. The results showed there was no association between HO-1 (GT)n repeat polymorphism and the cancer risk both at the allelic and genotypic level. However, in the stratified analysis, we observed an increased risk of squamous cell carcinoma in persons carrying the LL genotype and the LL+LS genotype as compared with those carrying the SS genotype. When the LS and SS genotypes were combined, the odds ratio for squamous cell carcinoma in LL-genotype carriers, were also significantly increased. No publication bias was observed. Conclusions: The LL genotype and L-allele carrying genotypes (LL+LS) of HO-1 (GT)n repeat polymorphism are potential genetic factors for developing squamous cell carcinoma. More large and well-designed studies are required for further validations.

• 한국식품영양학회지
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• 제22권2호
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• pp.279-285
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• 2009

맥문동을 열수 추출하여 전자공여능, 항산화력 및 항균력을 시험한 결과는 다음과 같다. 1. 전자공여능은 대조구인 BHA가 85 Vit C가 92, 녹차추출물(GT) 1 Brix%는 88, 반건조 맥문동 추출물(MDL) 10 Brix%는 65, 건조 맥문동 추출물(DL) 3 Brix%는 79를 나타내었다. 2. 지질과산화물 생성 억제 효과는 녹차추출물(GT) > 건조맥문동 추출물(DL) > 반건조 맥문동 추출물(MDL) 순으로 녹차추출물(GT)이 가장 높은 것으로 나타났다. 3. S. aureus에 대한 각 시료의 항균력은 BHA > 녹차추출물(GT) 순이며, 반건조 맥문동 추출물(MDL)과 건조 맥문동 추출물(DL)은 나타나지 않았다. E. coli에 대한 각 시료의 항균력 또한 BHA > 녹차추출물(GT) 순이며, 반건조 맥문동 추출물(MDL)과 건조 맥문동 추출물(DL)은 나타나지 않았다. 4. 맥문동 열수추출물의 전자공여능과 지질과산화물 생성 억제 효과는 반건조추출물(MDL)보다 건조추출물(DL)이 우수한 것으로 나타났으며, 항균력에서는 S. aureus와 E. coli에 대하여 항균력이 나타나지 않은 것으로 나타났다.

• 한국임상수의학회지
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• 제23권3호
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• pp.243-250
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• 2006

The chickens fed with the feeds supplemented with green tea(GT) and lactic acid bacteria(LB) were infected orally with 10,000 oocysts per chicken of E. maxima. The groups administered with the feeds supplemented with GT by 0.5% and 2.0% of feed showed the significant levels of decreasing in the number of oocysts shed for 5 days after E. maxima infection. The feeds supplemented with LB by 0.1% and 0.5% of feed were less effective in reducing the number of the fecal oocyst, compared with the groups administered with GT. To evaluate the immunoregulatory effects of the feed additives, the expression patterns of IL-2 and IFN-r in spleen cells were studied by RT-PCR and ELISA. The higher levels of IL-2 transcripts after E. maxima infection were observed in the groups with n, compared with the groups with LB and the mixture of GT and LB. The $IFN-\gamma$ mRNA bands were observed in the all of experimental groups except the uninfected control. The culture supernatants of Con A-stimulated spleen cells($5{\times}10^6cells/ml$) were measured for the concentration of IL-2 and $IFN-\gamma$ by ELISA. The levels of IL-2 and $IFN-\gamma$ on days 3 and 7 after E. maxima infection were significantly augmented in the groups with n. These results indicated that GT-supplemented feeds resulted in higher reduction of oocyst-shedding and more enhanced immune responses in the chicken infected with E. maxima, as compared with LB-supplemented feeds. According to the results, it was implicative that the supplements could be utilized for development of feed additives for anti-coccidiosis.

• Animal cells and systems
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• 제2권4호
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• pp.483-488
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• 1998

We previously found that a potent gonadotropin-releasing hormone (GnRH) agonist, buserelin, decreases GnRH promoter activity together with GnRH mRNA level, providing evidence for an autoregulatory mechanism operating at the level of GnRH gene transcription in immortalized GT1-1 neuronal cells. To examine whether agonist-induced decrease in GnRH mRNA level requires the continuous presence of buserelin, we performed a pulse-chase experiment of buserelin treatment. Short-term exposure (15 min) of GT1-1 neuronal cells to buserelin ($10{\mu}M$) was able to decrease GnRH mRNA levels when determined 24 h later. When GT1-1 cells were treated with buserelin ( $10{\mu}M$) for 30 min and then incubated for 1, 3, 6, 12, 24, and 48 h after buserelin removal, a significant decrease in GnRH mRNA levels was observed after the 12 h incubation period. These data indicate that inhibitory signaling upon buserelin treatment may occur rapidly, but requires a long time (at least 12 h) to significantly decrease the GnRH mRNA level. To examine the possible involvement of de novo synthesis and/or mRNA stability in buserelin-induced decrease in GnRH gene expression, actinomycin D ($5{\mu}m/ml$), a potent RNA synthesis blocker, was co-treated with buserelin. Actinomycin D alone failed to alter basal GnRH mRNA Revel, but blocked the buserelin-induced decrease in GnRH mRNA level at 12 h of post-treatment. These data suggest that buserelin may exert its inhibitory action by altering the stability of GnRH mRNA. Moreover, a polvsomal RNA separation by sucrose gradient centrifugation demonstrated that buserelin decreased the translational efficiency of the transcribed GnRH mRNA. Taken together, these results clearly indicate that GnRH agonist buserelin acts as an inhibitory signal at multiple levels such as transcription mRNA stability, and translation.