• Molecules and Cells
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• 제45권12호
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• pp.911-922
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• 2022

A structural protein of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), nucleocapsid (N) protein is phosphorylated by glycogen synthase kinase (GSK)-3 on the serine/arginine (SR) rich motif located in disordered regions. Although phosphorylation by GSK-3β constitutes a critical event for viral replication, the molecular mechanism underlying N phosphorylation is not well understood. In this study, we found the putative alpha-helix L/FxxxL/AxxRL motif known as the GSK-3 interacting domain (GID), found in many endogenous GSK-3β binding proteins, such as Axins, FRATs, WWOX, and GSKIP. Indeed, N interacts with GSK-3β similarly to Axin, and Leu to Glu substitution of the GID abolished the interaction, with loss of N phosphorylation. The N phosphorylation is also required for its structural loading in a virus-like particle (VLP). Compared to other coronaviruses, N of Sarbecovirus lineage including bat RaTG13 harbors a CDK1-primed phosphorylation site and Gly-rich linker for enhanced phosphorylation by GSK-3β. Furthermore, we found that the S202R mutant found in Delta and R203K/G204R mutant found in the Omicron variant allow increased abundance and hyper-phosphorylation of N. Our observations suggest that GID and mutations for increased phosphorylation in N may have contributed to the evolution of variants.

• 대한미생물학회지
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• 제35권3호
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• pp.263-271
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• 2000

A clinical isolate of Klebsiella pneumoniae K7746 produced the extended-spectrum ${\beta}$-lactamase (ESBL) SHV-12. A 6.6 kb BamHI fragment containing the $bla_{SHV-12}$ gene of K7746 strain was cloned into pCRScriptCAM vector resulting in the recombinant plasmid p7746-Cl. The restriction map of 3.6 kb inserted DNA and sequences immediately surrounding $bla_{SHV-12}$ of p7746-C1 were homologous to plasmid pMPA2a carrying $bla_{SHV-2a}$. In addition, both $bla_{SHV-12}$ and $bla_{SHV-2a}$ were expressed from a common hybrid promoter made of the -35 region derived from the left inverted repeat of IS26 and the -10 region from the $bla_{SHV}$ promoter itself. The results indicate that $bla_{SHV-12}$ and $bla_{SHV-2a}$ may have evolved from a common ancestor in the sequential order of $bla_{SHV-2a}$ first, followed by $bla_{SHV-12}$. Furthermore, by the PCR mapping method using primers corresponding to the IS26 and $bla_{SHV}$, the association between IS26 and $bla_{SHV}$ was studied in 12 clinical isolates carrying $bla_{SHV-2a}$, 27 clinical isolates carrying $bla_{SHV-12}$, and 5 reference strains carrying $bla_{SHV-1}$ to $bla_{SHV-5}$. All 39 strains carrying $bla_{SHV-2a}$ or $bla_{SHV-12}$ were positive by the PCR, providing confirmative evidence that IS26 has been involved in the evolution and dissemination of $bla_{SHV-2a}$ and $bla_{SHV-12}$. But 5 reference strains carrying $bla_{SHV-1}$ to $bla_{SHV-5}$ were negative by the PCR. Therefore, we concluded that the molecular evolutionary pathway of $bla_{SHV-2a}$ and $bla_{SHV-12}$ may be different from that of other $bla_{SHV-ESBL}$, e.g., $bla_{SHV-2}$, $bla_{SHV-3}$, $bla_{SHV-4}$, and $bla_{SHV-5}$.

• 상하수도학회지
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• 제32권4호
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• pp.309-315
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• 2018

Currently, the commercialization of the $5^{th}$ Generation (5G) service is becoming more prevalent in domestic communication network technology. This has reduced communication delay time and enabled large-capacity data transmission and video streaming services in real-time. In order to keep pace with these developments, K-water has introduced a smart process control system in water purification plants to monitor the status of the water purification process. However, since wireless networks are based on the public Long Term Evolution (LTE) network, communication delay time remains high, and high-resolution video services are limited. This is because communication networks still have a closed structure due to expense and security issues. Therefore, with 5G in its current form, it is very difficult to accommodate future services without improving the infrastructure of its communication networks. In recognition of these problems, this study implemented the authentication and management function of wireless networks on a wired network management system in the K-water Bansong water purification plant. The results confirmed that wired Local Area Network (LAN) services give a higher security performance than an expensive commercial wireless LAN system. This was achieved by using an Internet Protocol (IP) address management system of wired networks and the packet filtering function of the Layer2 (L2) switch. This study also confirmed that it is possible to create a wireless LAN service that is 3.7 times faster than the existing LTE communication network.

• 한국수산과학회지
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• 제40권4호
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• pp.210-219
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• 2007

The benthic marine algal flora and community structure were examined at five sites of the Taean Peninsula, Korea, during July-August 2005. Ninety-six algal species were Identified, including 14 green, 21 brown, and 60 red algae, and 1 marine plant. The common species that occurred at the five sites were Sargassum thunbergii, Gelidium divaricatum, Caulacanthus okamurae, Gracilavia vermiculophylla, and Neorhodomela aculeata. Sthunbergii was the dominant species in terms of coverage and biomass at ail of the study sites. The average biomass varied from $23.72g/m^2$ in dry weight at Chaeseokpo to $66.43g/m^2$ at Padori. The species could be divided into six functional groups in terms of morphological characteristics: 41 coarsely branched forms, 25 filamentous forms, 16 sheet forms, 7 thick leathery forms, including the marine plant Phyllospadix iwatensis, 4 crustose forms, and 3 Jointed calcareous forms. The seaweed communities at the five study sites were unstable and the environmental conditions were bad or very bad. Among the five study sites, the ecological evaluation index (EEI) and diversity index (H') were maximal at Padori at 2.29 and 1.98, respectively. By contrast, the dominance index (DI) was minimal at Padori (0.55) and maximal at Baramarae (0.96). Therefore, we conclude that the rocky shore at Padori has the best environment among the five study sites, although the species richness and biomass of seaweeds have declined continuously over the last 10 years.

• 소성∙가공
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• 제32권6호
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• pp.344-351
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• 2023

The use of Zn-Al-Mg alloy coatings for enhancing the corrosion resistance of steel sheets is gaining prominence over traditional Zn coatings. There is a growing demand for the development of thermal spray wires made from Zn-Al-Mg alloys, as a replacement for the existing wires produced using Al and Zn. This is particularly crucial to secure corrosion resistance and durability in the damaged areas of coated steel sheets caused by deformation and welding. This study focuses on the casting and extrusion processes of Zn-2Al-1Mg alloy for the fabrication of such spray wires and analyzes the changes in microstructure during the extrusion process. The Zn-2Al-1Mg alloy, cast in molds, was subjected to a heat treatment at 250 ℃ for 3 hours prior to extrusion. The extrusion process was carried out by heating both the material and the mold up to 300 ℃. Microstructural analysis was conducted using FE-SEM and EDS to differentiate each phase. The mechanical properties of the cast specimen were evaluated through compression tests at temperatures ranging from 200 to 300 ℃, with strain rates of 0.1 to 5 sec^-1. Vickers hardness testing was utilized to assess the inhomogeneity of mechanical properties in the radial direction of the extruded material. Finite Element Analysis (FEA) was employed to understand the inhomogeneity in stress and strain distribution during extrusion, which aids in understanding the impact of heterogeneous deformation on the microstructure during the process.

• Journal of Ecology and Environment
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• 제38권4호
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• pp.493-503
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• 2015

This study analyzed how spatial distribution of Himantormia lugubris is affected by the microenvironment in the Antarctic Specially Protected Area (ASPA) No. 171 located in the Barton Peninsula of King George Island that belongs to the maritime Antarctic. In order to determine the population structure of H. lugubris growing in Baekje Hill within ASPA No. 171, we counted the individuals of different size groups after dividing the population into 5 growth stages according to mean diameter as follows: ≤ 1 cm, 1-3 cm, 3-5 cm, 5-10 cm, and ≥ 10 cm. The count of H. lugubris individuals in each growth stage was converted into its percentage with respect to the entire population, which yielded the finding that stages 1 through 5 accounted for 32.8%, 25.3%, 15.9%, 22.5%, and 3.5%, respectively. This suggests that the population of H. lugubris in ASPA No. 171 has a stable reverse J-shaped population structure, with the younger individuals outnumbering mature ones. The mean density of H. lugubris was 17.6/0.25 m², mean canopy cover 13.3%, and the mean dry weight 37.8 g/0.25 m². It began to produce spore in the sizes over 3 cm, and most individuals measuring 5-10 cm were adults with sexually mature apothecia. The spatial distribution of H. lugubris was highly heterogeneous. The major factors influencing its distribution and performance were found to be the period covered by snow, wind direction, moisture, size of the substrate, and canopy cover of Usnea spp. Based on these factors, we constructed a prediction model for estimating the spatial distribution of H. lugubris. Conclusively, the major factors for the spatial distribution of H. lugubris were snow, wind, substrate and the competition with Usnea spp. These results are important for understanding of the distribution in the maritime Antarctic and evolution of H. lugubris that claims a unique life history and ecological niche.

• Animal Systematics, Evolution and Diversity
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• 제6권1호
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• pp.17-28
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• 1990

한국산 박새속(Parus) 6종 및 아종 11개 집단 159개체를 재료로 전기영동을 실시, 이들의 계통분류 및 종분화를 조사하였다. 박새(P. major) 3아종의 평균 유전적 변이정도는 일반적인 조류의 유전적 변이정도와 대체로 유사하였으나 나머지 좋은 변이정도가 낮았다. 박새 3아종의 집단 간 및 아종 간 유전적 근연치는 공히 S=0.95 이상으로 높았으며 이들은 집단간 근연치와 아종 간 근연치가 유사하였다. 종간에는 박새(P. major)와 곤줄박이(P. varius varius)의 유전적 근연치가 S=0.80으로 제일 높았고 쇠박새(P. palustrius hellmayri)와 진박새(P. ater amurensis)가 S=0.67로 제일 낮았다. 4종 평균 유전적 근연치는 S=0.72로 일반적인 조류의 근연치와 유사하였다. 이들의 분화연대를 추정한 결과 쇠박새는 약 180만년 전에 박새속 조류의 공통조상에서 분화되었다고 추정되며 그후 진박새는 약 160만년전, 곤줄박이는 약 100만년 전에 각각 분화되었고 박새 3아종은 약 10만년 전후에 분화되었을 것으로 추정된다.

• Animal Systematics, Evolution and Diversity
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• 제5권2호
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• pp.107-119
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• 1989

우리나라 연안과 담수역에 서식하는 큰가시고기과(Gasterosteidae)어류의 많은 표본은 1988년 3월부터 1989년 6월까지 채집하여 이들의 형태변이와 분류학적 위치에 대하여 검토하였다. 큰가시고기 Gasterosteus aculeatus 6개 조사집단의 체측인판수는 모두 32-35개였고 그 형태는 완판형으로 국내에서는 아직 육봉형이라고 생각된느 저판형이나 반판형은 발견되지 않았다. G. aculeatus의 척추골수, 세파수, 지느러미 기조수 등의 계수형질이나, 두장, 안경 및 등지느러미가시길이의 계측치는 집단간에 뚜렷한 차이가 없었다. 가시고기 Pungitius sinensis와 잔가시고기 P. kaibarae ssp. 집단의 체측인판수는 모두 31-35개의 완판형이었고, 등지느러미가시 기조수, 척추골수 및 체고비등에 있어서 2종간에 구별되었지만, 잔가시고기 P. kaibarae ssp.의 집단에는 등지느러미가시 기조막에 담회색을 띤 표본(White form)이 출현하였는데 이것은 이들이 서식하는 환경과 관련된 변이라고 본다. 이 2종의 염색체의 수는 모두 2N=42로서 서로 같지만 G.aculeatus의 핵형은 metacentrics이 6개, submetacentrics이 6개 subtelo-acrocentrics이 30개이고, P. sinensis와 P. kaibarae ssp.는 모두 metacentrics이 4개, submetacentrics이 4개 subtelo-acrocentrics이 34개로 2속 사이에는 서로 달랐다.

• 멤브레인
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• 제23권1호
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• pp.24-44
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• 2013

MBR 기술은 지난 20여 년 동안 처리성능과 효율성 그리고 비용절감 측면에서 빠른 속도로 발전하고 있다. 또한 안정적인 하수처리와 하수재이용관점에서 핵심기술로 널리 인식되고 있다. 본고에서는 MBR 기술의 개발과 상업적 응용에 관한 발전과정을 재조명하고 세계 시장의 전망을 제시하고자 한다. 주요 적용기술에 대해 다음 5가지 측면에서 검토하여 제시하였는데 1) MBR 기술의 진화, 2) MRBs의 상업용 기술, 3) 대용량 MBR 플랜트 설치 사례, 4) MBR 시장의 성장, 5) 기술의 발전방향 순으로 제시하였다. 마지막으로 MBRs에 대한 경제적, 환경적, 그리고 기술적 측면에서 향후 발전방향을 1) 초기투자비, 2) 처리 수질, 3) 분리막 소재/모듈, 4) MBR 장비와 공정, 5) 운영비용, 향후 6) 혐기성 MBRs 공정과 같은 차세대 기술 분야로 나누어 제시하였다.

• 터널과지하공간
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• 제33권3호
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• pp.189-207
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• 2023

In the present study, the thermoshearing experiment on a rough rock fracture were modeled using a three-dimensional grain-based distinct element model (GBDEM). The experiment was conducted by the Korea Institute of Construction Technology to investigate the progressive shear failure of fracture under the influence of thermal stress in a critical stress state. The numerical model employs an assembly of multiple polyhedral grains and their interfaces to represent the rock sample, and calculates the coupled thermo-mechanical behavior of the grains (blocks) and the interfaces (contacts) using 3DEC, a DEM code. The primary focus was on simulating the temperature evolution, generation of thermal stress, and shear and normal displacements of the fracture. Two fracture models, namely the mated fracture model and the unmated fracture model, were constructed based on the degree of surface matedness, and their respective behaviors were compared and analyzed. By leveraging the advantage of the DEM, the contact area between the fracture surfaces was continuously monitored during the simulation, enabling an examination of its influence on shear behavior. The numerical results demonstrated distinct differences depending on the degree of the surface matedness at the initial stage. In the mated fracture model, where the surfaces were in almost full contact, the characteristic stages of peak stress and residual stress commonly observed in shear behavior of natural rock joints were reasonably replicated, despite exhibiting discrepancies with the experimental results. The analysis of contact area variation over time confirmed that our numerical model effectively simulated the abrupt normal dilation and shear slip, stress softening phenomenon, and transition to the residual state that occur during the peak stress stage. The unmated fracture model, which closely resembled the experimental specimen, showed qualitative agreement with the experimental observations, including heat transfer characteristics, the progressive shear failure process induced by heating, and the increase in thermal stress. However, there were some mismatches between the numerical and experimental results regarding the onset of fracture slip and the magnitudes of fracture stress and displacement. This research was conducted as part of DECOVALEX-2023 Task G, and we expect the numerical model to be enhanced through continued collaboration with other research teams and validated in further studies.