• Journal of Radiation Protection and Research
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• v.17 no.1
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• pp.43-56
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• 1992

As one of the methods to ameliorate the ray effects which are the nature of anomalous computational effects due to the discretization of the angular variable in discrete ordinates approximations, a computational program, named TWODET (TWO dimensional Discrete Element Transport), has developed in 2 dimensional cartesian coordinates system using the discrete elements method, in which the discrete angle quadratures are steered by the spatially dependent angular fluxes. The results of the TWODET calculation with K-2, L-3 discrete angular quadratures, in the problem of a centrally located, isotropically emitting flat source in an absorbing square, are shown to be more accurate than that of the DOT 4.3 calculation with S-10 full symmetry angular quadratures, in remedy of the ray effect at the edge flux distributions of the square. But the computing time of the TWODET is about 4 times more than that of the DOT 4.3. In the problem of vacuum boundaries just outside of the source region in an absorbing square, the results of the TWODET calculation are shown severely anomalous ray effects, due to the sudden discontinuity between the source and the vacuum, like as the results of the DOT 4.3 calculation. In the probelm of an external source in an absorbing square in which a highly absorbing medium is added, the results of the TWODET calculation with K-3, L-4 show a good ones like as, somewhat more than, that of the DOT 4.3 calculation with S-10.

• Journal of Radiation Protection and Research
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• v.17 no.2
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• pp.61-70
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• 1992

Photon, neutron and beta radiation fields were measured at PWR plants which are the representative types of nuclear power plant operated in Korea. The photon energy spectra were measured at locations in the auxiliary building during operation period and in the containment vessel(C/V) during shutdown period using a portable gamma spectrometer with a HPGe detector. The distribution of average energy was found to range from 440 to 780 keV in the C/V and from 280 keV to 760 keV in the auxiliary building, respectively. The average neutron energy measured at the five locations around the operation deck in the C/V in operation using a BMSS (Bonner Multi-Sphere Spectrometer) ranged from 20 keV to 210 keV. A computer code, BUNKI was used to unfold the spectrum. The beta energy spectra in the C/V and in the auxiliary building in annual outage were determined using 14 smear samples taken from the highly contaminated areas. The analysis showed that the representative corrosion product, $^{60}Co$ made main contribution to the beta energy field.

• Journal of Life Science
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• v.22 no.9
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• pp.1137-1144
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• 2012

Inflammation is a host defense mechanism that is activated in response to harmful substances or pathogens. However, an excessive inflammatory response is a problem in itself. Macrophages secrete inflammatory mediators such as nitric oxide (NO) or cytokines through various pathways such as the nuclear factor kappa B (NF-${\kappa}B$)-activated pathway after recognizing pathogen-like lipopolysaccharides (LPSs). In this study, anti-inflammatory effects of Eupatorium chinensis var. simplicifolium (EUC) extracts were investigated using LPS-stimulated RAW 264.7 macrophages. The EUC root extract significantly reduced NO production, inducible nitric oxide synthase (iNOS) expression, and cyclooxygenase-2 expression in a concentration-dependent manner. In addition, the EUC root extract reduced phosphorylation of mitogen-activated protein kinases and protein kinase B, which is upstream of NF-${\kappa}B$. The EUC root extract also reduced the degradation of inhibitory kappa B. These results indicate that EUC root extract exerts anti-inflammatory effects, which are mediated by inhibition of iNOS expression and the NF-${\kappa}B$ pathway.

• Korean Journal of Microbiology
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• v.52 no.2
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• pp.236-241
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• 2016

The Schizosaccharomyces pombe $sdu1^+$ gene, belonging to the PPPDE superfamily of deubiquitinating enzyme (DUB) genes, was previously shown to encode a protein with ubiquitin C-terminal hydrolase (UCH) activity and to participate in the response against oxidative and nitrosative stresses. This work focused on the reactive oxygen species (ROS)-dependent regulation of the S. pombe $sdu1^+$ gene. UCH activities, encoded by the $sdu1^+$ gene, were attenuated in the S. pombe cells exposed to $H_2O_2$, superoxide radical-generating menadione (MD), and nitric oxide (NO)-generating sodium nitroprusside (SNP). Reduced glutathione (GSH) and its precursor N-acetylcysteine (NAC) were able to significantly enhance the UCH activities in the absence or presence of $H_2O_2$. However, the influences of both GSH and NAC on the ROS levels in the absence or presence of $H_2O_2$ were opposite to their effects on the UCH activities under the same conditions. The UCH activities in the Sdu1-overexpressing S. pombe cells were also diminished under exposure to $H_2O_2$, MD and SNP, but still remained to be higher than those in the vector control cells. In brief, it is proposed that the S. pombe $sdu1^+$ gene is regulated by ROS in a negative manner, the meaning of which largely remains elusive.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.11a
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• pp.73-78
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• 2005

본 연구에서는 서울시 한강에 위치한 교량을 대상으로 다양한 조망점에 따른 경관조명의 물리량을 측정하고 그 특성을 분석함으로써 동일한 연구대상에 대하여 조망점이 달라졌을 때 나타나는 물리적 변화를 통해 경관조명분야의 물리량평가방법론의 새로운 접근방법론을 제시하는 것이 목적이다. 이를 위하여 연구대상의 선정은 교량구조형식에 따라 분류하고. 경관조명이 설치된 교량 17개소 중 다양한 조망점과 현장측정의 편리성 등을 고려하여 광진교(거더교), 올림픽대교(사장교), 동작대교(트러스교), 동작대교(아치교)를 연구대상으로 선정하였다. 조망점은 한강둔치를 이용하는 방문객들이 바라보는 투시뷰, 교량주변 건축물에서 바라보는 건물뷰 그리고 교량 위를 이동하면서 바라보는 주행뷰로 구분하였다. 이러한 연구방법으로 도출된 결과는 동일한 경관조명연출을 토대로 교량별 조망점에 따른 휘도측정 및 분석에서 측정되는 각도, 거리, 방향에 따라 정형화된 비율은 아니지만 휘도값에 있어서 차이가 있다는 것을 확인 할 수 있었으며, 투시뷰와 건물뷰는 동일한 교량 구성요소를 갖고 있어 상호간 비교 분석이 가능하고 경관조명평가 요소로서 그 기능을 담당 할 수 있다고 판단되며, 주행뷰는 교량형식과 가로등의 영향을 많이 받으므로 평가요소로써 조망점을 활용하기에는 조금 더 깊은 연구가 선행되어야 할 것으로 보인다. 따라서 경관조명을 평가함에 있어 다양하게 바라보는 조망점은 조명연출로 인한 시각적 인식에 차이를 유발시킬 수 있어 경관조명을 평가할 때 다양한 조망점의 설정이 보다 객관적이고 정확한 분석이 가능할 것으로 판단된다.ridinium의 분포는 chlorophyll-a농도와 밀접한 관련성이 있었다. 담수적조의 현존량은 상류지역에서 $8.5\;{\times}\;10^3\;cell\;mL^L{-1}$로서 많았고, 댐부근의 하류지역($4.4\;{\times}\;10^2\;cell\;mL^L{-1}$)으로 갈수록 감소하는 양상을 보였다. 또한, 담수적조의 원인종으로 규조류 Synedra acus와 남조류 Microcystis aeruginosa도 소량관찰되었다. 저수지의 수질 부영양화 현상은 기존 경사사면형 농경지를 기반으로 조성되었으므로 저층으로부터 풍부한 영양환경을 내재하고 있었고, 담수 초기에 발생할 수 있는 가능성을 포함하고 있었다. 또한 유입수량의 부족과 현재 수질개선을 위해 적용하고 있는 수중폭기시설등의 물리적인 영향도 직 ${\cdot}$ 간접적으로 작용하였을 것으로 추정되었다 따라서 향후 이에 대한 중장기적인 모니터링이 필요하였고 유역과 저수지의 통합적인 수질관리계획 이 요구되었다.group으로, 용존산소량, 전기전도도, pH, 인산염이 정점 3, 4, 5에서 같은 group으로 묶였다.유의적인 CAT 활성 증가효과가 나타났고, 간조직의 시토졸 1획분에서는 대조군 대비 15${\sim}$27%의 CAT 활성 증가효과가 인정되었다. 이상의 결과에서 목초액의 장기간 투여는 간조직 중의 활성산소의 억제효과뿐만 아니라 방어시스템으로서 활성산소 제거효소의 역할도 충실히 수행하여 노화를 효과적으로 예방하고 억제할 수 있을 것으로 기

• Strategy21
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• s.37
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• pp.242-274
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• 2015

2015년 5월 수중발사 탄도미사일(SLBM) 발사시험을 통해 북한은 전 세계의 이목을 또 다시 집중시켰다. 북한은 2013년 제3차 핵실험을 감행한 이후 최근까지도 탄도미사일과 로켓 발사 등의 무력도발을 지속해 왔다. 이와 같은 북한의 무력도발은 한반도의 안정뿐만 아니라 미국 본토의 안보에도 매우 부정적인 영향을 미치고 있다. 지금까지 미국은 북한의 핵미사일 개발 저지를 위해 경제적 또는 군사적 방안들을 선별적으로 적용해 왔다. 그러나, 이러한 미국의 노력에도 불구하고 북한은 여전히 핵미사일을 개발하겠다는 꿈을 포기하지 않고 있는 것이 사실이다. 본 논문은 북한의 핵미사일 개발에 대한 미국의 대안적 전략(Alternative Strategy)을 제시하는데 그 목적이 있다. 필자는 대안적 전략 제시에 앞서 북한의 핵과 탄도미사일 개발현황을 내용(Contents)과 맥락(Context) 차원에서 분석하고 미 오바마 행정부의 대북전략을 비판적으로 검토하였다. 그리고 대안적 전략으로 동맹국과 함께 경제적(Sticky Power), 군사적(Sharp Power) 수단의 동기화(Synchronizing)를 통해 북한이 감당하기 힘든 전략적 환경을 조성(Shaping the Strategic Environment)하는 것이 '북한의 핵개발 포기' 라는 전략목표를 달성하는 방안 임을 강조하고 있다. 미국이 대안적 전략목표를 달성하기 위해서는 경제적 수단으로 ① 북한의 자금세탁 및 위조지폐 발행국 지정, ② 북한을 지원하는 모든 해외자산에 대한 제재조치, ③ 북한의 테러지원국 재지정, ④ 북한 제재를 위한 미국의 입법추진, ⑤ 대량살상무기 관련 금수품목의 확대를 적용함과 동시에 군사적 수단으로 ① 대량살상무기 비확산 활동 강화, ② 대탄도미사일 전략 개발 및 정보(ISR: Intelligence Surveillance and Reconnaissance) 공유, 맞춤형 억제전략(TDS: Tailored Deterrence Strategy)의 구체화 등을 통한 한·미 군사 억제방안의 강화, 그리고 ③ SM-3, THAAD(Terminal High Altitude Area Defense) 등 한·미·일 3자간 MD(Missile Defense)체제의 구축 등을 동기화하여 적용해야만 할 것이다. 미국의 대안적 전략은 ① 북한의 핵미사일 개발에 대한 중국의 협력방지, ② 한·중간 경제관계의 악화, ③ 한·일간의 역사적 긴장관계라는 위험요소를 내포하고 있는 것 또한 사실이다. 따라서 미국이 대안적 전략목표인 '북한의 비핵화' 달성을 위해서는 이와 같은 위험요소를 완화시키는 노력도 병행되어야 할 것이다. 끝으로, 미국은 북한의 김정은이 핵미사일 개발 포기라는 상이한 방향의 전략적 결정을 할 경우에 대비하여 한·미 연합훈련의 보류, 북한에 대한 경제제재조치 해제 등 북한과의 협상 가능성도 열어두고 이에 대해서도 철저하게 준비해 나가야 할 것이다.

• Journal of Radiation Protection and Research
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• v.13 no.2
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• pp.9-20
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• 1988

In order to quantify the contribution of cosmic-ray ionizing component to the dose given by natural background radiation, a series of measurement has been carried out using LiF TLDs for about one and a half years on quarterly basis. Three different types of LiF TLDs namely, chips and PTFE based disks of $^{7}LiF$, and the same disks of $^{6}LiF$ for identifying possible contribution of neutron component were used. Measurements were made by placing badge-incased TLDs in a lead castle of 10 to 15cm thick installed in a room on the third floor of a four-story building in CNU Daedeok campus for 5 cycles of 90 days. For comparison a series of spectrometric study was also performed for the energy region over 3MeV using a 3'${\phi}\;{\times}\;3$'NaI(Tl) scintillation detector in association with an MCA of 1024 channels, and it was found that the data obtained by the TLDs placed in the lead castle indicate 75% of the dose given by outdoor cosmic-ray component. The results obtained by the TLDs through correction for shielding loss show that the outdoor dose contribution of ionizing component of cosmic rays at this campus is $34.3{\pm}1.1nGy/h$ which satisfactorily agrees with that expected for our particular location of measurement.

• Economic and Environmental Geology
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• v.52 no.5
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• pp.409-425
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• 2019

Marine terraces, a step-like landform, are important geologic markers that provide tectonic information during the Quaternary Period. Marine terraces are well developed along all coastlines(East, West, and South) of the Korean Peninsula, those along the East coastline are the most distinctive. The marine terraces of the East coastline are classified into 4-6 flights that are several meters or several tens of meters above the present sea level. It is believed that these terraces, except for the lowest one, were formed in the middle Pleistocene. In the base of the OSL age dating results and Blake excursion events of magnetostratigraphy, the $2^{nd}$ and $3^{rd}$ terraces are correlated to the last interglacial stage. Considering the marine terraces linked to a sea-level curve of the Pleistocene, it is thought that regional tectonic movements have uplifted the East coastal area since the middle Pleistocene. Besides, former shorelines of each terrace have varied elevations from Gangreung to Busan bay, which can be divided into four regions, namely, Gangreung-Yonghanri(I), Homikot-Najung(II), Najung-Bangeojin(III), and Waesung-Busan Bay(IV). The former shorelines of each terrace at both Gangreung-Yonghanri(I) and Najung-Bangeojin(III) are higher than those in the other two regions, due to block movements by regional faults such as the Ocheon Fault or its subsidiaries, the Gampo Lineament and Ulsan Fault. Uplift rate of the East coast ranges from 0.2 m/ky to 0.3 m/ky, but each region shows different uplift rate.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.4
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• pp.365-376
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• 2021

In general, domestic streams and rivers are composed of alluvial rivers consisting of sand and gravel beds. These rivers can cause erosion and riverbed changes due to sudden changes in flow rates, such as floods, torrential rains, and heavy rains. In particular, there are various types of erosion, such as contraction erosion caused by changes in river shape, or local erosion occurring around obstacles such as piers, abutments or embankments. In addition, river changes can occur in various forms, such as static or dynamic periods, due to limitations such as flow rate, velocity, and shear stress. This study focused on the erosions of embankments directly related to human casualties among various river structures, and evaluated limit velocities and critical shear stress in order to identify changes in strength of natural materials by identifying the characteristics of natural hoan materials and resistance to erosions. In particular, the limitations of materials according to the type of materials in the river, characteristics of particles, and size of particles were studied using Soil loss, which is a change in the volume of the revetment material, and it is intended to be used as basic data for river design and restoration.

• Journal of Life Science
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• v.31 no.1
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• pp.83-89
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• 2021

Uu-ilys, an i-type lysozyme from spoon worm (Urechis unicinctus), is an innate immune factor that plays an important role in the defense against pathogens. It also possesses non-enzymatic antibacterial activity. Thus, there is a possibility to develop an antimicrobial model peptide from Uu-ilys. In this study, we report the design, production, and antibacterial activity of an Uu-ilys analog that exhibits antibacterial activity. The Uu-ilys structure was fragmented according to its secondary structures to predict the regions with antimicrobial activity using antimicrobial peptide (AMP) prediction tools from different AMP databases. A peptide containing the C-terminal fragment was predicted to exert antimicrobial activity. The chosen fragment was designated as an Uu-ilys analog containing the C-terminal fragment, Uu-ilys-CF. To examine the possibility of developing an AMP using the sequence of Uu-ilys-CF, recombinant fusion protein (TrxA-Uu-ilys-CF) was produced in an expression system that was heterologous. The produced fusion protein was cleaved after methionine leaving Uu-ilys-CF free from the fusion protein. This was then isolated through high performance liquid chromatography and reverse phase column, CapCell-Pak C18. The antibacterial activity of Uu-ilys-CF against different microbial strains (four gram-positive, six gram-negative, and one fungal strain) were assessed through the ultrasensitive radial diffusion assay (URDA). Among the bacterial strains tested, Salmonella enterica was the most susceptible. While the fungal strain tested was not susceptible to Uu-ilys-CF, broad spectrum antibacterial activity was observed.