Measurement of $^{93}Nb(n,n{\alpha})^{89m}Y$, $^{93}Nb(n,{\alpha})^{90m}Y$ and $^{93}Nb(n,2n)^{92m}Nb$ Cross Sections for 14 MeV Neutrons

김영석,김낙배,정기형,박혜일,Kim, Y.S.,Kim, N.B.,Chung, K.H.,Bak, H.I. Korean Nuclear Society 1986 Nuclear Engineering and Technology Vol.18 No.2

The $^{93}Nb(n,n\alpha)^{89m}Y$, $^{93}Nb(n,{\alpha})^{90m}Y$ and $^{93}Nb(n,2n)^{92m}Nb$ cross sections at a neutron energy of 14.6 MeV have been measured relative to the $^{27}Al(n,p)^{27}Mg$ and $^{27}Al(n,{\alpha})^{24}Na$ cross sections. A small accelerator utilizing $T(D,n)^4He$ reaction was used as a neutron source and the neutron energy spread is about 0.4MeV at the sample. All induced activities were measured with a 70cc HPGe detector in the same geometry.

The Repressive Activity of Hepatitis C Virus Core Protein on the Transcription of p21 is Regulated by PKA-Mediated Phosphorylation

Chung,E. Y.,Lee,M. N.,Ahn,J. Y.,Jang,K. L. 한국생명과학회 2001 한국생명과학회 학술발표회 Vol.31 No.-

HCV core protein is known to repress the transcription of p21 directly in a p53-independent manner. In this study, the region of HCV core protein responsible for the transcriptional repression of p21 promoter was determined. N-terminal half of core protein almost completely lost the ability to repress p21 promoter, indicating that the domain required for the majority of p21 repression is located between amino acid positions 91 and 191. The trans -repression activity of HCV core mutant S99L on p21 gene expression was similar to that of wild type core protein whereas mutation of the 116th amino aicd Ser into either Ile or Ala complely abolished the repressive ability of HCV core protein. In addition, the trans -repression activity of HCV core mutant S116N was similar to that of wild type core protein, suggesting that an acidic aspartate residue can mimic the effect of phosphorylation. When treated with a PKA inhibitor (HA1004), the inhibitory activity of wild-type HCV core protein was dose-dependently decreased and was completely lost at the concentration of 5μM. On the contrary, the repression activity of HCV core protein was increased by treatment with a PKA activator, indicating, that the p21 repressive activity of HCV core protein is regulated by phosphorylation at 5-116 by PKA. The growth rate of HCV Core-expressing cell line was about 2 fold higher compared to that of the parent cells, suggesting that the repression of p21 transcription by HCV core protein is actually connected to the stimulation of cell growth.

케이슨 튜브 가물막이의 시공안정성 검토

정성교,김성렬,N. T. Dung,김민석 東亞大學校 建設技術硏究所 2005 硏究論文集 Vol.29 No.1

금속판막교체술 후 초기 6개월간 Warfarin 유지용량 변화와 이에 영향을 미치는 요인 분석

최수안,정영미,정소영,한현주,이병구,박경호,조남춘 한국병원약사회 2000 병원약사회지 Vol.17 No.2

Patients with mechanical heart valve prostheses require lifelong anticoagulation to reduce the risks of valve thrombosis and thromboembolism. These risks are greatest in the first three months after surgery and are exacerbated by inadequate anticoagulation. Although it is recognised that anticoagulant control is worse in the first few months after starting treatment, the relationship of this to warfarin dosing and the frequency of monitoring is unclear. We have therefore assessed the precision of anticoagulant control in the first three months after mechanical heart valve replacement and taken and analysis of influencing factors. Eighty-five consecutive patients who underwent isolated mechanical heart valve replacement between April 1997 and March 1998, were identified retrospectively from hospital records. Of these were excluded patients in taking a medicine appearing drug interactions or decreasing the liver function. The clinical data included patients demographics, warfain dosages and INR changes for the first six months after surgery, weight changes, warfain maintenance dosages by age, sex, valve type. Warfarin mean daily doses were 3.79±1.9, 3.60±1.67, 4.04±1.5, 4.36±1.6, 4.62±1.42, 4.98±1.6㎎ at postdischarge, 2 weeks, 1, 2, 3 and 6 months, respectively. Theses increased significantly. Patients gained weight but it was not significantly between weight and warfain dosages changes. Theses were not influenced by the valve type, age but significantly increased 19.3±0.31% male, 80±0.84% female, respectively. These results suggested that there is a sex difference in the anticoagulation effects of warfarin. The anticoagulant response to warfarin is changed for the first three month after mechanical valve replacement. Therefore it is nescessary to control strictly for this periods.

대가축 난자에서 수정시 일어나는 난활성과 그 이후의 변화

엄상준,정길생,정병현,박흠대,도정태,김남형,이훈택 건국대학교 동물자원연구센터 1998 動物資源硏究誌 Vol.19 No.-

본 연구는 세포질내 구성물질, 즉 미세소관, 미세섬유, 표층과립의 움직임을 조사하였다. 미세섬유의 형성, 표층과립의 분포 등은 렉틴과 로다민으로 표지된 팔로이딘에 의한 형광염색법을 사용하여 공촛점주현미경으로 조사하였다. GV단계에서는 표층과립이 피질 주위에 비교적 두터운 층으로 형성되어 있었으며, 미세섬유도 세포피질 주위에 두터운 층으로 형성되어 있었으며, 미세섬유도 세포피질 주위에 두터운 형태로 형성되어 있었다. GVBD 이후에는 미세섬유는 핵 주위에 두터운 층을 형성하고 표층과립은 피질 주위에서 관찰되었다. Cytochalasin B을 처리하면 미세섬유의 형성이 방해되는데, 이로 인해 표층과립이 세포피질로 이동하는 것이 억제되었으며, 정자침입 후에는 표층과립 내용물들은 위란강내로 고르게 분포됨을 알 수 있었다. 이러한 결과는 미세섬유의 형성이 난자의 성숙, 수정과정 중 표층과립의 분포와 움직임에 연관이 있음을 나타내어 준다. In the paper we examined the dynamics of cytoplasmic content, such as microtubules, microfilaments and cortical granules. The microfilament assembly and cortical granule distribution were imaged with fluorescent labeled lectin and rhodamine labeled phalloidin under laser scanning confocal microscopy. At germinal vesicle stage, cortical granule organelles were located around the cell cortex and were present as a relatively thick area on the oolema. Microfilaments were also observed in a thick uniform area around the cell cortex. Following germinal vesicle breckdown, microfilaments concentrated to the condensed chromatin and cortical granules were observed in the cortex. Treatment with cytochalasin B inhibited microfilament polymerization and prevented movement of cortical granules to the cortex. Cortical graule exudate following sperm penetration was evenly distributed in the entire perivitelline space. These results suggested that the microfilament assembly is involved in the distribution, movement and exocytosis of cortical granules during maturation and fertilization.

In Vitro Induction of Differentiation by Ginsenosides in F9 Teratocarcinoma Cells

Lee, Y.-N.,Lee, H.-Y.,Chung, H.-Y.,Kim, S.-I.,Lee, S.-K.,Park, B.-C.,Kim, K.-W. 부산대학교 유전공학연구소 1996 분자생물학 연구보 Vol.12 No.-

The aim of this study was to determine the ability of the ginsenosides, extracts of Panax ginseng C.A. Meyer, to cause differentiation of F9 teratocarcinoma stem cells as a model system. F9 stem cells cultured in the presence of the ginsenosides together with dibutyryl cyclic AMP (dbcAMP) became parietal endoderm-like cells. Moreover, the expression of differentiation marker genes, such as laminin B1 and type IV collagen, was increased after treatment with the ginsenosides. Among the various purified ginsenosides, Rh_1, and Rh_2, were the most effective at causing differentiation of F9 cells. Since ginsenosides and glucocorticoid hormone have similar chemical structures, we examined the possibility of the involvement of a glucocoticoid receptor (GR) in the differentiation process induced by the ginsenosides. According to Southwestern blot analysis, a 94 kDa protein regarded as a GR was detected. In F9 cells cultured in the medium containing the ginsenosides Rh_1, or Rh_2. In addition, F9 stem cells treated with the ginsenosides Rh_1, or Rh_2 and with RU486, a glucocorticoid antagonist with a high affinity for the GR, did not differentiate into endoderm cells morphologically, and the expression of laminin B1 gene was not induced in these cells. In a gel mobility shift assay, protein factors capable of binding to the glucocorticoid responsive element (GRE) specifically were detected in nuclear extracts of the ginsenoside-treated F9 cells. Moreover, overexpression of GR by cotransfection of GR expression vector and GRE-luciferase vector enhanced the transactivation activity of GRE promoter in the presence of ginsenosides Rh_1 or Rh_2 and was further augmented by dbcAMP. In addition, ginsenosides Rh_1 and Rh_2 bound to a GR assessed by whole-cell binding assay, even though the specific binding affinity was weaker compared to dexamethasone. Based on these data, we suggest that the ginsenosides Rh_1 and Rh_2 cause the differentiation of F9 cells and the effects of ginsenosides might be exerted bia binding with a GR or its analogous nuclear receptor. Copyright ⓒ 1966 Elsevier Science Ltd.

The Differential Effect of Whole-body Irradiation on Morphine- and β-Endorphin-Induced Antinociceptive Actions in Mice

Kyung N. Kim,Ki M. Chung KOREAN ACADAMY OF ORAL BIOLOGY 2009 International Journal of Oral Biology Vol.34 No.3

Whole-body γ-irradiation(WBI), which produces an oxidative stress, is reported to attenuate the acute antinociceptive action of morphine (a μ-opioid receptor agonist), but not DPLPE (a δ-opioid receptor agonist), in mice. Recently, we also reported that antinociceptive effect of morphine, but not β-endorphin (a novel ε-opioid receptor agonist), was attenuated by oxidative stress. These findings prompted us to investigate the effect of WBI on the antinociception of morphine and β-endorphin in mice. Mice were exposed to WBI (5 Gy) from a 60 Co gamma-source and tested 2 hours later for antinociception produced by intracerebroventricular administration of morphine or β-endorphin using the hot water tail-immersion and the writhing tests. WBI significantly attenuated the antinociception produced by morphine only in the hot water tail-immersion test, whereas the antinociception of β-endorphin was significantly potentiated by WBI in both tests. These results demonstrate a differential sensitivity of μ- and ε-opioid receptors to WBI, and support the hypothesis that morphine and β-endorphin administered supraspinally produce antinociception by different neuronal mechanisms.

저온잠열축열용 TMA 포접화합물에 Ethanol을 첨가한 경우의 냉각특성에 관한 연구

강승현,김광일,정종헌,김창오,김진흥,정낙규 朝鮮大學校 機械技術硏究所 2003 機械技術硏究 Vol.6 No.2

This study aims to improve subcooling and phase change temperature of ThlA clathrate when ethanol is added. The running time of refrigerator is reduced. Also. subcooling and phase change temperature of TMA clathrate are improved. In view of the results achieved the improvement of low temperature thermal storage system is expected.

Geotechnical Characteristics of Marine Clay in Busan New Port

Chung, S.G.,Ryu, C.K.,Beak, S.H.,Huh, D.Y.,Jo, K.Y.,Lee, N.K.,Ninjgarav 東亞大學校建設技術硏究所 2004 硏究論文集 Vol.28 No.1

Since early 1990s reclamation projects in Busan and its vicinity in Nakdong River plain have been performed for industrial and residential complexes. As well it has started to build a new port (Busan Newport) due to increase in overloads of Busan port since late 1990s. In the area the sedimentary deposit is composed of soft clay of about 30m thick, thin sand layer of 3-4m thick, hard clayey soil, and then basal conglomerates and sandy sediments, total thickness of which is about 70m at the maximum under seawater. For the huge project many contract companies have simultaneously performed geotechnical investigations to get design parameters. Based on the harmful experiences gained by the previous projects, it was also required to pay careful attention to sampling and laboratory and field tests for the project. Nevertheless the results of laboratory tests were so scattered and then resulted in difficulty to evaluate the design parameters. Existing data has been reviewed to evaluate the validity or cause of their variation. In addition geological study, sampling and soil tests have been carefully carried out at a few locations. Using the results the clay would be effectively characterized for depositional environment and its relation to soil properties.

Action of Dopamine as Inhibitory Neuromodulator in Jellyfish Synapse

Chung, Jun-Mo,Spencer, Andrew N. The Korea Science and Technology Center 1998 BMB Reports Vol.31 No.3

Dopamine (DA) acts on swimming motor neurons (SMNs) of Polyorchis penicillatus as an inhibitory neurotransmitter by hyperpolarizing their membrane potentials, which results from the activation of voltage-sensitive potassium channels mediated through a D₂-type receptor. In addition, DA, and not the hyperpolarized membrane potential, directly decreased the input resistance of SMNs by ca. 50% from 1.42 to 0.68 GΩ. It strongly indicates that DA can shunt other excitatory synaptic signals onto SMNs where DA usually elicited much greater responses in their neurites than soma. All these evidences suggest that DA may operate in this primitive nervous system in dual modes as an inhibitory neurotransmitter and neuromodulator as well.