THERRESTRIAL IMPACT CRATERING CHRONOLOGY: A PRELIMINARY ANALYSIS

Moon, Hong-Kyu,Mi, Byung-Hee,Fletcher, Andre-B.,Kim, Bong-Gyu The Korean Space Science Society 2001 Journal of Astronomy and Space Sciences Vol.18 No.3

We have recently compiled a database of the properties of 192 impact craters, which supercedes previous compilations. Using our database, the impact structures found in North America, Europe and Australia have been examined; these cratonic areas have been relatively stable for considerably long geological periods, and thus have been best preserved. It is confirmed that there is a close correlation between the geological epoch boundaries, the epochs of mass extinctions, antral the "timing" of impacts. In addition, the terrestrial cumulative flux of objects >20km is found to be $1.77{\times}10^{-15}km^{-2}yr^{-1}$, over the last 120 Myr, which is much smaller than the published values in McEwen et al. (1997) and Shoemaker (1998) ($5.6{\pm}2.8{\times}10^{-15}km^{-2}yr^{-1}$. For terrestrial impact structures with D> 50 km, the apparent cumulative flux over the last 2450 Myr is ~50 times smaller than the corresponding value for the Moon. If we assume that the Earth and the Moon suffered the same level of bombardment over this time, this would mean that the actual flux of impacting bodies, capable of making craters with D)50 km, was ~ 50 times larger than the apparent flux estimated from the currently known terrestrial records.

Critical role of bile acid (BA) in the cellular entry and permissiveness of Hepatitis B virus in vitro

Hong‑Jai Lee,Bo‑Young Shin,Jae‑Seung Moon,Ailyn Fadriquela,Selikem Abla Nuwormegbe,Chun‑Chang Ho,Jin‑Su Shin,Jee‑Sang Yoon,Sang‑Kyou Lee,Soo‑Ki Kim 대한독성 유전단백체 학회 2020 Molecular & cellular toxicology Vol.16 No.3

Background Lack of universal replication system for hepatitis B virus with narrow host range and organ tropism has hampered to uncover the pathogenesis of HBV. Previously, we reported the essentiality of humoral milieu and its components toward HBV and hepatitis C virus survival/viability in vitro. Of these components, the precise role of enterohepatic humoral milieu such as bile acid (BA) on HBV cultivation in vitro and in vivo is unknown. Objective We explored whether BA, specifically taurochenodeoxycholic acid (tCDCA) would directly regulate the viral DNA and surface antigen expression of HBV in vitro, consequently rendering HBV to enter into human or murine immortalized hepatocytes, and non-hepatocytes. Result We found that higher concentration of taurochenodeoxycholic acid (tCDCA) is able to preserve the genomic stability of HBV in cell-free DMEM, showing higher the surface antigenicity than taurocholic acid (tCA). In line, we found that in vitro cell culture condition (100 μmol/L of tCDCA coupled with 1 × 108 g e/mL HBV) would be optimal for HBV entry into target cells. Using this, human (HepG2, Huh7), and rodent (Hepa1c1c7, H4-II-E) hepatoma cell lines were infected by HBV, as evidenced by the presence of HBV biomarkers (HBsAg, and HBV DNA in culture supernatant, as well as HBcAg in cell). Further, cellular entry test revealed that HBV is able to infect 12 different non-hepatic cell lines regardless of species, and organ/tissue, consequently reproducing progeny as confirmed by HBV biomarkers. Last, reinfection test showed that the progenies of HBV from immortalized HepG2, and Hepa1c1c7 cells are able to enter into each or vice versa naïve HepG2, and Hepa1c1c7 cells with or without BA. Conclusion This study demonstrates that enterohepatic humoral milieu such as BA, specifically tCDCA would directly regulate HBV DNA and its surface antigen expression in vitro, consequently rendering HBV to enter into human or murine immortalized hepatocytes, and non-hepatocytes. This is the first note to render HBV permissive to human or rodent hepatic and non-hepatic cells via sole manipulation of humoral milieu, thus establishing the platform for in vitro robust replication system of HBV.

성대마비환자를 대상으로 시행한 후두근전도검사의 임상적 유용성

최홍식,최영준,문상우,김태만,최홍식,최영준,문상우,김태만 대한이비인후과학회 1999 대한이비인후과학회지 두경부외과학 Vol.42 No.2

지난 2년간의 학회지 "신경정신의학" 심사 평가보고

김찬형,김세주,김도관,김성곤,박원명,송동호,박용천,이영문,오강섭,정영철,이상열,김주한,이동영,이헌정,함병주,김율리,김문두,김정진,이강욱,천근아,김재진,홍진표,홍승철 大韓神經精神醫學會 2007 신경정신의학 Vol.46 No.6

터널지보용 격자지보의 시공성 평가 연구

문홍득 진주산업대학교 건설기술연구소 1998 건설기술연구소보 Vol.1 No.-

Recently, a lattice girder is used in tunnelling as a tunnel support. A lattice girder is a new steel support developed in Europe for the replacement of an existing H-shaped steel set, which is reported to have some problems in installation. In this study, to evaluate the workability of a lattice girder in tunnelling in Korea, field observations were performed at a subway tunnel construction site with a small section. Also, features of lattice girder in field observations were compared with those of a H-shaped steel set respectively.

olanzapin과 Risperidone의 급성 및 만성 투여기가 흰쥐 전전두피질의 Dopamine 농도에 미치는 영향

문선근,정영철,은홍배,황익근,박태원 大韓神經精神醫學會 2002 신경정신의학 Vol.41 No.1

항정신병약물들이 전전두피질의 세포외 dopamine 농도에 미치는 영향은 이 약물들의 음성 증상에 대한 효과와 관련이 있는 것으로 보고 되고 있다. 따라서 본 연구에서는 최근 국내에서 많이 사용되고 있는 olanzapine과 risperidone을 흰쥐에 급성 및 만성 투여를 한 후, 이들 약물들이 전전두피질의 세포외 dopamine 농도에 미치는 영향을 알아보고자 하였다. 샘플은 생체 내 뇌 미세투석법(in vivo brain microdialysis)을 이용하여 얻었고 샘플내 dopamine의 농도는 전기화학적 검출법(electrochemical detection : ECD)을 사용하는 고압액체크로마토그라피(high pressure liquid chromatography : HPLC)로 측정하였다. 그 결과는 다음과 같다. 1) Olanzapine과 risperidone의 급성 투여는 전전두피질 부취의 세포외 dopamine 농도를 증가시켰으며 증가의 정도는 용량 의존적이었다. 2) Olanzapine과 risperidone의 급성 투여에 의해 전전두피질 부위에 나타난 세포외 dopamine 농도의 최고치는 두 약물간에 유의한 차이가 없었다. 3) Olanzapine과 risperidone의 만성 투여는 전전두피질 부위의 세포외 dopamine 농도를 증가시켰으나 그 증가의 정도가 급성 투여에 비해 모두 감소하는 내성 현상이 보였다. 4) Olanzapine과 risperidone의 만성 투여에 의해 전전두피질 부위에 나타나는 세포외 dopamine 농도의 최고치는 olanzapine과 risperidone에 비해 유의하게 높았다. 이상의 결과들은 Olanzapine과 risperidone의 음성 증상에 대한 임상적 효과가 이들 약물이 전전두피질의 세포외 dopamine 농도를 증가시키는 효과와 관견이 있음을 제시한다. Object : It is reported that the effect of antipsychotics on the extracellular dopamine levels in the prefrontal cortex is related to the their effect on the negative symptoms. Therefore, we investigated the acute and chronic effects of olanzapine and risperidone on the extracellular dopamine concentrations in the prefrontal cortex of rat. Samples were obtained using in vivo brain microdialysis. Method : Dopamine levels in the samples were measured by high pressure liquid chromatography with electrochemical detection. Results : 1) Both the acute treatment of olanzapine and risperidone increased the extracellular dopamine concentrations in the prefrontal cortex, dose-dependently. 2) There was a no significant difference in the maximal change of the extracellular dopamine concentrations in the prefrontal cortex induced by the acute treatment of olanzapine and risperidone. 3) Both the chronic treatment of olanzapine and risperidone also increased the extracellular dopamine concentrations in the prefrontal cortex, but they showed the tolerance effect that the degree of increase was smaller than that of the acute treatment. 4) As for the maximal changes of the extracellular dopamine concentrations in the prefrontal cortex induced by the chronic treatment of planzapine and risperidone, the effect of the former was greater than that of the latter. Conclusion : These results suggest that the effects of olanzapine and risperdone on the negative symptoms are related to the increased extracellular dopamine concentrations in the prefrontal cortex induced by these drugs.

Fitzgerald 의 초기작품이 특징

洪文杓 군산대학교 1982 群山水産專門大學 硏究報告 Vol.16 No.2

Perhasps no less important a factor than cultural patterns in a foreign reputation is his publisher. However Fitzgerald has only recently been published by a few printers in Korea. With the view of analyzing and detailing his early works, these materials are cited from "Though-book" a childhood diary, and "The Ledger", an autobiography. Foeshadowing of his major themes can be found in his early pieces of fiction and he was even then exploring the techniques that were later to appeare in his full-length fiction. To be sought a comprehensive subject of their fiction, there are some born authors who do not create for their world, but for their readers'. This is particularly true of Fitzgerald, and he sowed the lively harvest that our era goes to reap.

Supercritical Nano-Plating 시스템에서 전기도금된 니켈 막의 표면특성에 관한 연구

홍교민,김문선,정재관 한국공업화학회 2003 응용화학 Vol.7 No.2

In this study, experiments of a nickel electroplating were performed in a supercritical nano-plating(SCNP) system using CO₂as a supercritical fluid. Surface properties of nickel film electroplated by the electrolyte solution with 0.2 vol% surfactant and volume ratio of CO₂and electrolyte as 1:9 was the best in the plating properties, where surface roughness(Ra) of nickel film plated for 30 min by SCNP was 0.021 ㎛. The property of plated film with this new method was better than that by a conventional method.

자기 동일성의 상실과 회복 : <나의 침실로>에 대한 언술적 의미

홍문표 명지대학교 인문과학연구소 1998 인문과학연구논총 Vol.18 No.-

Gatsby와 그의 世界

홍문표 군산대학교 1981 群山水産專門大學 硏究報告 Vol.15 No.2

Degrading human nature in American society after the World War I raised its head seriously, and accordingly the young generations were pursuing a false dream. F. Scott Fitzgerald pointed out an American Dream and he tried to be the romantic readiness by the most naive person. For the symbolic presentation in "The Great Gatsby" Fitzgerald gave a great deal of suggestion from "The Waste Land". Actually the setting and background Fitzgerald employs in "The Great Gatsby" reveals a suffering crucifix for the contemporary nothingness Nick returns West, declaring himself, Gatsby, Jorden, Tom and Daisy, all born Westerners, as "subtly unadaptable to Eastern life," and recalling the East in a place of death, directlessness, materialism, indifference, and coldness. In conclusion it is not only an reassurance of tragic problems among the human beings but their generalization.