• 한국터널지하공간학회 논문집
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• 제20권1호
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• pp.145-160
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• 2018

초장대 해저터널은 환기를 위한 연직갱 또는 경사갱 설치에 공간적으로 많은 제한을 받게 되므로 일부 인공섬을 건설하여 환기를 수행할 필요가 있다. 그러나 인공섬 설치는 건설의 어려움뿐만 아니라 건설비용이 증가하게 되므로 인공섬 설치를 최소화할 필요가 있다. 이에 따라 환기거리가 증가하여 누풍에 의한 공급 풍량이 커지게 되면, 공사 중 환기를 위한 덕트 설치가 불가능해지거나 팬 정압 및 동력이 상당히 증가하게 된다. 따라서 초장대 해저터널을 건설하기 위해서는 이러한 현실적인 문제를 극복하고 시공 중 터널 내 환경을 쾌적한 상태로 유지할 수 있는 기술력이 필요하다. 선행 연구에서 우리는 누풍이 이 문제들을 해결하는 핵심 인자이며 실험 결과 새로운 접속방식의 누풍율은 대략 $1.46mm^2/m^2$임을 밝혔다(Jo et al., 2017). 본 연구에서는 새로운 접속방식이 적용된 시제품의 누풍율 측정 결과를 제시하고 기존 접속방식의 누풍 성능 개선을 위해 덕트 내부에 연질막 적용시의 누풍 성능 개선을 실험적으로 분석하였다.

• 생명과학회지
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• 제22권3호
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• pp.354-359
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• 2012

실험에서는 소태나무, 편백의 유용자원으로의 이용가능성을 알아보기 위해, 소태나무 잎과 편백 목질부를 분쇄한 후 추출물을 제조하여 이들 각각의 총 폴리페놀 및 플라보노이드의 함량을 측정 후 항산화제로 널리 알려진 BHA와의 비교측정으로 항산화 활성을 검색해 보았다. 먼저 소태나무 잎, 편백나무의 메탄올 추출물에 존재하는 총 폴리페놀 및 플라보노이드 함량을 측정한 결과, 소태나무 잎 추출물의 총 폴리페놀 함량은 $367.52{\mu}g/mg$, 편백나무 추출물의 총 폴리페놀 함량은 $138.3{\mu}g/mg$으로 편백나무 보다는 소태나무 잎에서 높은 폴리페놀 함량을 보였다. 총 플라보노이드 함량 역시 소태나무 잎과 편백나무에서 각각 46.41 및 $8.12{\mu}g/mg$으로 소태나무 잎에서 플라보노이드 함량이 높게 나타났다. 각 시료의 DPPH 소거 활성을 농도별로 측정한 결과, $10{\mu}g/ml$의 농도에서 소태나무 잎이 97%, $200{\mu}g/ml$의 농도에서 편백나무가 90%의 소거능을 보였고, BHA ($5{\mu}g/ml$)에서 81% 정도의 항산화능을 보였다. 또한 $ABTS+^{\bullet}$ 소거활성을 Trolox와 비교한 결과, $ABTS+^{\bullet}$ 소거활성법에서 표준물질로 사용되는 Trolox는 $60{\mu}M$에서 94% 정도의 소거활성을 보였고, 소태나무 잎 추출물은 $10{\mu}g/ml$에서 68%, 편백나무는 $100{\mu}g/ml$에서 89% 정도의 소거활성을 보였다. FRAP 활성 측정결과 소태나무 잎에서 $8.52{\mu}mol/{\mu}g$, 편백나무에서 $1.77{\mu}mol/{\mu}g$ 나타났으며 특히 소태나무 잎에서 높은 $Fe^{2+}$ 함량을 나타내어 total polyphenol contents과 유사한 경향을 보였다. 따라서 본 연구 결과들로부터 소태나무 잎은 높은 폴리페놀 함량에 기인한 강력한 항산화 작용을 가지는 것으로 생각된다.

• 한국자동차공학회논문집
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• 제16권1호
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• pp.121-126
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• 2008

The cooling heat transfer coefficient of $CO_2$ (R-744) in a horizontal and helically coiled tube was investigated experimentally. The main components of the refrigerant loop are a receiver, a variable-speed pump, a mass flow meter, a pre-heater, evaporator and gas cooler (test section). The test section consists of a horizontal stainless steel tube and hellically coiled copper tube of 4.57 and 7.75 mm. The experiments were conducted at saturation temperature of 100 to $20^{\circ}C$, and mass flux of 200 to $500kg/m^2s$. The test results showed the variation of the heat transfer coefficient tended to decrease as cooling pressure of $CO_2$ increased. The heat transfer coefficient with respect to mass flux increased as mass flux increased. The experimental results were also compared with the existing correlations for the supercritical heat transfer coefficient, which generally underpredicted the measured data. However, the experimental data showed a relatively good agreement with the correlations of Pitla et al. except for the pseudo critical temperature.

• 한국산업보건학회지
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• 제11권2호
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• pp.118-125
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• 2001

Recently, biochemical analysis using hemoglobin adduct is frequently performed to evaluate the exposure to chemical carcinogens. However, data on the effect of co-exposure with other chemicals on hemoglobin adduct formation are seldom provided. The objective of this study is to evaluate the effects of pretreatment of ethanol(EtOH) and phenobarbital(PB), which are known to affect metabolism of xenobiotics, on the formation of hemoglobin adducts in the rats(Sprague-Dawley) administered benzidine(BZ). The experimental rats were divided into control, EtOH, and P8 groups. Rats were pretreated with EtOH or PB 24 hours before the oral administration of BZ. Blood sampling was taken before the administration of the chemicals and 0.5, 3, 6, 9, 12, 24, 48, 72, 96, and 144 hours after the administration of the BZ in 5 rats each. The blood was separated into hemoglobin and plasma immediately after taking the blood samples, and the adducts were undergone basic hydrolysis to convert them into aromatic amines. Hydrolyzed BZ, monoacetylbenzidine (MABZ), and 4-aminobiphenyl(4ABP) were separated by reversed-phase liquid chromatography without derivatization, and quantitative analyses of them were performed by a highperformance liquid chromatograph equipped with electrochemical detector. The quantitative amount of the metabolites was expressed by hemoglobin binding index(HBI), BZ-, MABZ-, and 4ABP-HBI of EtOH and PB groups were increased more than those of control group. These results are attributable to the fact that EtOH and PB induced N-hydroxylation related to the hemoglobin adduct formation. The ratio of N-acetylation (viz, MABZ-HBI/BZ-HBI) showed no significant difference between EtOH group and control group. It means that EtOH increased N-hydroxylation and N-acetylation in a similar degree. The N-acetylation ratio of PB group was relatively lower than control group because the PB increased N-hydroxylation induction. The N-acetylation ratios of all groups were higher than 1 during the entire experimental period. This result suggests that the effects of EtOH or PB need to be considered in the biochemical monitoring for the assessment of intermittent exposure of benzidine.

• Animal Systematics, Evolution and Diversity
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• 제27권3호
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• pp.205-212
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• 2011

Platorchestia monodi (Mateus et al., 1986), the beach hopper, commonly lives in sea shores and was previously reported only from the Atlantic regions, such as Mid-Atlantic islands, Brazilian coast, and Israel. We present the first record of this species in the Pacific region. The present species can be clearly distinguished from related species by the shapes of gnathopods 1-2 and development of sexual dimorphism in antenna 2 and pereopod 7. Descriptions of the diagnostic characteristics of the species are provided on the text. In addition, this paper also provided the partial sequence of the mitochondrial cytochrome c oxidase subunit 1 (CO1) gene of the species for its molecular characteristics.

• 한국약용작물학회지
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• 제13권5호
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• pp.293-297
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• 2005

A thoredoxin (CTRX) gene was cloned and characterized from a full length cDNA library prepared from taproot of three-year old Codonopsis lanceolata. A CTRX was 666 nucleotides long and has an open reading frame of 372 bp with 124 amino acid residues (pI = 4.92). The deduced amino acid sequence of the CTRX matched to the previously reported plant thioredoxin h genes. The deduced amino acid sequence of CTRX exhibited the similarity of 33-67% among previously registered thioredoxin genes. The expression of CTRX in leaves of Codonopsis lanceolata was increased by wounding and 1 mM $H_2O_2$, but decreased by 0.1 mM cadmium.

• 천문학회보
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• 제36권1호
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• pp.62.2-62.2
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• 2011

It is well known that the cluster environment can change the atomic gas properties of galaxies through tidal interactions and/or by the hot cluster medium. Meanwhile, the molecular gas is expected to be less vulnerable to its surroundings due to its higher density, and no obvious influence of the environment on the molecular gas properties had been found among cluster spirals until recently. However, in a recent study by Fumagalli et al. (2009) of a sub-sample of Virgo spirals, it has been suggested that HI deficient galaxies can be also CO deficient. In order to further investigate if the HI deficiency indeed can result in the deficiency in molecular gas content, we compare the global CO and HI gas properties of Virgo spirals with those of galaxies in the Ursa Major cluster and the Pisces cluster, much lower density environments than Virgo. We discuss possible consequences of molecular gas deficiency in star formation activity of spiral galaxies in high density environment.

• 생약학회지
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• 제44권1호
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• pp.47-52
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• 2013

We invesitagat the effects of antioxidant and suppression of MMP-1 in UV-irradiated human dermal fibroblasts (HDF) by schizandrin isolated from Schisandra chinensis. Ultrasonic technique was used to extract schizandrin from S. chinensis. The higher contents of schizandrin (6.34 mg/ml) in 70% EtOH extract obtained by ultrasonic treatment at 20 MHz for 2 h during 10 days. Schizandrin had antioxidant activities. Schizandrin (1-10 ${\mu}g/ml$) induced a significant dose-dependent decrease in the expression fo MMP-1 protein. These results suggest that schizandrin is a potential candidate for the prevention and treatment of skin aging.

• 대한한방피부미용학회지
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• 제1권1호
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• pp.91-97
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• 2005

(1) Objectives: To discover natural skin-lightening agents, we have evaluated the inhibitory activity of EtOH extracts from 20 medicinal plants against mushroom tyrosinase. (2) Methods: Tyrosinase activity was determined by the dopachrome method using L-tyrosine as the substrates. (3) Results: Of the plant extracts tested, the extracts of 4 plants, Albizzia julibrissin, Curcuma longa, Anethum graveolens and Sophora flavescens, exhibited potent inhibitory activity (> 50%) in mushroom tyrosinase assay. Four plant extract, extracts of Agrimonia pilosa, Paeonia moutan, Magnolia obovata and Eugenia caryophyllata also showed relatively strong inhibitory (> 40%) against mushroom tyrosinase. (4) Conclusion: These active medicinal plants may be useful for the development of skin-whitening agents. Since the active medicinal plants may contain effective tyrosinase inhibitors even more than kojic acid, further study to identify the active constituents from the plants is expected.

• Clinical and Experimental Reproductive Medicine
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• 제25권1호
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• pp.35-41
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• 1998

This study was carried out to investigate the development rates of human embryos co-cultured with cumulus cells to each blastocyst stage. Human zygotes were co-cultured on cumulus cell monolayer in YS medium supplemented with 20% hFF. On day 2, if patient had four or more "good" embryos (regular blastomeres without fragmentation), embryos were further cultured for 72hrs. Blastocysts on day 5 were classified into early blastocyst (ErB), early expanding blastocyst (EEB), middle expanding Blastocyst (MEB), and expanded blastocyst (EdB) on the basis of their morphological aspects of trophectoderm cells and blastocoele. Subsequently, maximum 3 of best blastocysts were transferred in 486 cycles. The results in this study were as follows: Patients who had four or more "good" embryos on day 2 were 498 persons, but patients whose embryos could not be transferred due to failure in development to the blastocyst stage on day 5 were 12 persons (2.4%). The development rate of embryos to the blastocyst stage was 58.2% (2,885/4,957) on day 5, and the rates that developed to the ErB, EEB, MEB, and EdB stage were 15.0% (743/4,957), 14.9% (739/4,957), 14.4% (714/ 4,957), and 13.9% (689/4,957), respectively. Total 1366 blastocysts were transferred in 486 cycles (mean number=2.81). The implantation rate and the ongoing implantation rate obtained by observing the number of G-sac and FHB were 29.9% (409/1,366) and 22.5% (308/1,366), respectively. The clinical pregnancy rate was 51.2% (249/486), and the ongoing pregnancy rate' was 39.1% (190/486). Among women showing ongoing pregnancy, women with singleton were 50% (95/190), women with twin were 37.9% (72/190), and women with triplet were 12.1% (23/190). Although triplet pregnancy rate in this study was high such as 12.1%, because many blastocysts with high viability were produced in our co-culture system using cumulus cells on day 5, we really believe that a multiple pregnancy except twin should not occur by selecting good embryos for maximum two blastocyst transfer. These results demonstrate that autologous cumulus cells may be used for the production of blastocysts with high developmental competence, and the use of autologous cumulus cells to be collected easily, and to be treated conveniently at OPU must be an effective means for obtaining high implantation and pregnancy rate.