• Nuclear Engineering and Technology
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• v.26 no.1
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• pp.1-8
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• 1994

The flame speed correlation considering thermal-hydraulic phenomena under severe accidents is proposed and correction coefficients are defined. This correlation modifies the pressure dependency in Iijima-Takeno correlation and adds the steam suppression effects to it in the anticipated hydrogen and steam concentration ranges under severe accidents. The existing models of flame speed due to hydrogen combustion under severe accidents are based on the experiments which were performed merely at room temperature and atmospheric pressure. They have difficulty in predicting a accurate flame speed in a case of high temperature and pressure during severe accidents. Thus the flame structure is assumed as a prerequisite to the reliable determination of flame speed and theoretical model is developed. To examine the validity, flame speeds in various conditions calculated by this model are compared with those obtained by the calculation of the existing correlations of the codes such as improved HECTR and MAAP. Also the steam suppression ratio is quantified and the steam suppression coefficient is defined as a composition of mixture. Initial temperature and pressure dependencies are investigated and correction coefficents are determined. More experimental studies can be recommended to improve this correlation to its further works.

• Journal of Practical Agriculture & Fisheries Research
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• v.24 no.1
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• pp.14-22
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• 2022

The purpose of this study is to provide evidence for discovering functional materials through the anti-inflammatory efficacy screening of randomly selected medicinal herbs. We prepared 70% ethanol extracts from 10 herbs and evaluated for the inhibitory effect of NO production on LPS-stimulated mouse macrophage cell line Raw 264.7. As a result, it was confirmed that the Chrysanthemi Zawadskii Herba (CZ) extract had the highest effect of inhibiting NO production induced by LPS. We therefore measured and compared NO inhibitory effects at different concentrations (10, 50, 250 ㎍/mL) of 70% ethanol and water extract of CZ. It was observed that both ethanol and water treatment groups inhibited NO production in a concentration-dependent manner in both ethanol and water treatment groups. In particular, it was confirmed that the CZ 70% ethanol extract (99.97%) had a higher NO inhibitory effect than the water extract (93.32%) in the high concentration (250 ㎍/mL) treatment group. There was no effect of CZ extract on cell viability at all concentrations used in the experiment. Moreover, it was shown that CZ ethanol extract remarkably inhibited the expression of VCAM-1 induced by TNF-𝛼, and it was slightly decreased even by treatment with water extract. This study suggests that Chrysanthemi Zawadskii Herba has potential as a functional substance that regulates vascular inflammation.

• The Korean Journal of Zoology
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• v.34 no.1
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• pp.20-30
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• 1991

지렁이(L. rubelIus) 체액내의 적혈구용혈능깍 단백질분해능을 확인하였다. 지렁이의 체액 0. 33 $\mu$l속에 있는 용혈인자는 9 $\times$ 1011 rat RBCs를 2분만에 완전히 용혈시켰으며, 다른 포유류들의 적혈구에도 약간의 차이는 있으나 비슷한 용혈능을 보였고, 이 용혈인자는 지렁이의 혈구가 아닌 몸체조직에서 분비되는 것으로 생각되었다. 용혈인자는 pH 6.5-7.5사이에서 활성이 가장 강하였고, 63'c로 30분 열처리할 경우 활성이 완전히 없어졌으며, 2-mercaptoethanol은 용혈인자의 활성을 증가시켰다. 이 인자의 활성도는 여러가지의 당류, LPS, cholesterol, prosphatidyl Choline, Ch10ropromazine, Sphin90myelin 및 FG2+, Fe3+, CU2+, ZR2+ 등의 금속이온에 의하여 활성이 저해되었다. 한편 지렁이 체액내의 단백질 분해인자는 BSA와 19G를 여러 조각으로 분해시켰으며 이 분해인자는 PMSF및 TLCK에 의하여 활성이 억제되지 않았다. 지렁이의 체강에는 용혈소를 분비하는 박테리아들이 존재하였으나 이들 박테리아들의 용혈소는 지렁이의 용혈인자와는 전기영동이동도에서 차이가 있었다.

• The Korean Journal of Zoology
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• v.38 no.2
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• pp.177-185
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• 1995

두 지역에서 채집한 초파리 자연집단에 대하여 난소발생이상 실험에 의한 P 인자 활성과 세포질형을 분석하여 P 전이인자의 계통형을 조사하였다 전체 238 isofemale line을 조사한 결과 strong P와 true M은 존재하지 않았고, 0(weak P)와 M'(pseudo M) strain이 전체의 98.74%를 차지하여 가장 우세하게 분포하고 있었다. P$\pi$25.1 probe를 이용한 in situ hybridization을 행하여 P 전이인자의 copy수를 조사한 결과 평균 42.12개로 나타났으며, 0와 M'의 계통형 간에 유의적인 차이는 없었다 그러나 염색체 firm당 COPy수는 X염색체가 상염색체의 좌 우 각 arm보다 다소 높게 분포하고 있었고. 염색체상 P 전이인자의 삽입부위에 대한 특이적 좌위는 존재하지 않았다 P 전이인자의 분자구조에 대한 변이형을 조사하기 위하여 southern blot hybridization을 행한 결과 2.9kb의 완전한 크기의 분자를 포함하여 여러종류의 단편들이 확인되었다 조사한 모든 isofemale line에서 KP(1. 15kb)인자를 포함하고 있었으며 이들 KP인자가 P-M System의 난소발생이상을 표현하는데 있어 억제적 작용을 하는 것으로 판단되었다.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.4
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• pp.413-421
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• 2014

Corticotropin-releasing factor (CRF) is involved in the stress response and there is increasing evidence that stress influences skin disease such as hair loss. In cultured human hair follicles, CRF inhibits hair shaft elongation, induces premature regression and promotes the apoptosis of hair matrix keratinocytes. We investigated whether CRF influences the dermal papilla cells (DPC) that play pivotal roles in hair growth and cycling. Human DPCs were treated with CRF, adrenocorticotropic hormone (ACTH) and cortisol, key stress hormones along the hypothalamic-pituitary -adrenal (HPA) axis for 1-24 h. Interestingly, CRF modulated the expression of cytokines related to hair growth (KGF, Wnt5a, $TGF{\beta}-2$, Nexin) and increased cAMP production in cultured DPCs. CRF receptors were down-regulated by negative feedback systems. Pretreatment of CRF receptor antagonists or protein kinase A (PKA) inhibitor prevented the CRF-induced modulation. Since the CRF induces proopiomelanocortin (POMC) expression through the cAMP/PKA pathway, we analyzed POMC mRNA. CRF stimulated POMC expression in cultured human DPCs, yet we were unable to detect ACTH levels by western blot. These results indicate that CRF operates within DPCs through CRF receptors along the classical CRF signaling pathway and CRF receptor antagonists could serve as potential therapeutic and cosmetic agents for stress-induced hair loss.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1389-1395
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• 2000

Cervical cancer has been one of the leading causes of female death from cancer worldwide with about 500,000 deaths per year. A strong association between certain human papillomaviruses (HPV types 16 and 18) and cervical cancer has been well known. An extract of natural products, Rhus, has been used to investigate whether this agent has the ability of inhibiting the oncogenes E6 and E7 of HPV type 16. This Rhus inhibited the proliferation of human cervical cancer cell lines (C-33A, SiHa, Caski) and HaCaT keratinocytes in a dose response manner. In vitro binding assay and ELISA showed that Rhus inhibited the in vitro binding of E6 and E6AP which are essential for the binding and degradation of the tumor suppressor p53. In addition, Rhus inhibited the in vitro binding of E7 and Rb which essential tumor suppressor for the control of cell cycle. The level of mRNA for E6 was also decreased by Rhus while that of E7 mRNA was not changed. Our data suggested that Rhus inhibited the oncogenecity of E6 and E7 of HPV 16 type, thus can be used as a putative anti-HPV agent for the treatment of cervical carcinomas by HPV.

• Journal of Life Science
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• v.20 no.2
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• pp.275-280
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• 2010

Sulforaphane is a naturally occurring member of the iosothiocyanate family, which reveals chemopreventive capacities including anti-cancer, anti-inflammation and inhibition of MMP-9 activities. In this study, we investigated the effect of sulforaphane on the expression of matrix metalloproteinase-9 (MMP-9) in lipopolysaccharide (LPS)-induced Raw 264.7 cells. Sulforaphane strikingly suppressed the LPS-induced MMP-9 activity and mRNA expression in a dose-dependent manner. In addition, sulforaphane inhibited not only the LPS-induced MMP-9 promoter activity but also LPS-mediated activator protein-1 (AP-1) and nuclear factor-kB (NF-${\kappa}B$) promoter activity. Transient transfection by MMP-9 constructs, in which specific transcriptional factors were mutagenized, indicated that the effects of LPS and sulforaphane were mediated via AP-1 and NF-${\kappa}B$ response elements. We found that sulforaphane had the ability to suppress LPS-induced invasion in vitro. Taken together, these results demonstrated that sulforaphane effectively suppressed LPS-induced MMP-9 expression via modulation of promoter elements (AP-1 and NF-${\kappa}B$) in MMP-9 transcriptional activation.

• The Journal of Internal Korean Medicine
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• v.25 no.4
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• pp.18-24
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• 2004

연구배경 : 플라스미노겐 활성 억제인자-1 (plasminogen activator inhibitor-1; PAI-1)은 허혈성 뇌경색의 발생의 원인이 되는 섬유소 용해작용의 저하를 매개하는 인자로서, PAI-1의 작용이 촉진되면 섬유소 용해기능이 저하되어 관상동맥 및 뇌혈관질환의 발생을 증가시키게 된다. PAI-1 유전자의 촉진자(promoter) 영역에는 -675 4G/5G (4G/5G)와A -844G (A/G)의 두 개의 유전자 다형성이 존재하며, 이는 PAI-1의 유전자 전사과정에 영향을 미쳐 혈청 PAI-1의 농도를 증가시키고 결과적으로 허혈성 뇌경색의 발생확률을 높이는 작용을 하게 된다. 연구방법 : 허혈성 뇌경색으로 진단 받은 167명의 환자와 173명의 건강인의 말초혈액에서 DNA를 분리한 후 PAI-1의 4G/5G와 A/G 유전자 다형성에 대한 연쇄중합반응 및 제한효소 절편길이 다형성 (polymerase chain reaction-restriction fragment length polymorphism; PCR-RFLP) 방법을 이용하여 허혈성 뇌경색 발생과 유전자 다형성과의 관계를 비교 분석하였다. 결과 : 허혈성 뇌경색 환자에서의 4G/4G의 유전자형의 빈도는 15.0%으로 정상 대조군의 33.5%에 비해 현저하게 낮게 나타났다 (P < 0.0001). 각각의 유전자형과 허혈성 뇌경색의 발생 위험도 (odd ratio ; OR)와의 관계를 분석했을 때 4G/4G 유전자형을 가질 경우 위험도는 0.35배로 현저하게 낮아졌으며, (P < 0.0001), 5G/5G 유전자형을 가질 경우 위험도는 4.49배 로 현저하게 높아졌다 (P < 0.0001). 그러나, A/G 유전자 다형성과 허혈성 뇌경색의 발생과는 유의한 연관성을 발견하지 못하였다. 결론 : 이상의 결과로 볼 때 PAI-1 유전자의 4G/4G 유전자형은 허혈성 뇌경색의 발생 비율을 감소시키는 작용을 하는 것으로 여겨진다.

• Journal of Life Science
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• v.6 no.4
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• pp.234-240
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• 1996

A double-stranded RNA binding factor (RBF), characterized as an inhibitor of PKR kinase in our previous study, was evaluated for its RNA binding specificities by RNA gel electrophoretic mobility shift analysis and membrane filter binding assay, RBF displayed affinities for a broad range of RNAs including viral RNAs and synthetic RNAs consiting of stem and loop structures. GC-rich RNA stem helices as short as 11 bp are suggested to represent the minimal binding motif for RBF. RBF binding to all the natural RNAs tested was reversible by poly(I): poly(C) addition, but E. coli 5S RNA was inefficient.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.2
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• pp.329-332
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• 2002

We investigated the effect of Sarcodon aspratus extract on expression of cell cycle regulators. Methanol extract of Sarcodon aspratus showed a growth suppression on HepG2. As shown by western blot analysis, the expressions of cyclin A and Dl known as cell cycle regulators were decreased after treatment of Sarcodon aspratus extract. On the other hand, the expression of cyclin Bl was increased in the presence of Sarcodon aspratus extract. Furthermore, the expression of p53, a tumor supressor gene, and p27, a cell cycle dependent protein kinase inhibitor, were increased, whereas the expression of PCNA was decreased. In conclusion, our study suggests that growth inhibitory effect of Sardodon aspratus methanol extract on HepG2 is induced by cell cycle arrest in the Gl phase caused by decrease in cyclin A, Dl expressions and increases in p53, p27 expression.