• 천문학회보
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• 제45권1호
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• pp.52.2-52.2
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• 2020

At quasi-perpendicular shocks in the high-�� (��=Pgas/Pmag~100) intracluster medium (ICM), various microinstabilities occur by the temperature anisotropies and/or drift motions of plasma. In the downstream, the Alfvén ion cyclotron instability (AIC) due to the ion temperature anisotropy (Ti⊥>Ti║) is triggered by shock-reflected ions, the whistler instability (WI) is driven by the electron temperature anisotropy (Te⊥>Te║) as a consequence of the shock compression of magnetic fields, and the mirror instability is generated due to the ion and/or electron temperature anisotropy. At the shock foot, the modified two stream instability (MTSI) is possibly excited by the cross-field drift between ions and electrons. In the upstream, electron firehose instability (EFI) is driven by the electron temperature anisotropy or the relative drift between incoming and reflected electrons. These microinstabilities play important roles in the particle acceleration in ICM shocks, so understanding of the microinstabilities and the resultant plasma waves is essential. In this study, based on a linear stability analysis, the basic properties of the microinstabilities in ICM shocks and the ion/electron scale fluctuations are described. We then discuss the implication of our work on the electron pre-acceleration in ICM shocks.

• 천문학회보
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• 제46권1호
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• pp.36.2-36.2
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• 2021

In the outskirts of galaxy clusters, weak shocks with M_s < ~3 appear as radio relics where the synchrotron radiation is emitted from cosmic-ray (CR) electrons. To understand the production of CR electrons through the so-called diffusive shock acceleration (DSA), the electron injection into the DSA process at shocks in the hot intracluster medium (ICM) has to be described. However, the injection remains as an unsolved, outstanding problem. To explore this problem, 2D Particle-in-Cell (PIC) simulations were performed. In this talk, we present the electron preacceleration mechanism mediated by multi-scale plasma waves in the shock transition zone. In particular, we find that the electron preacceleration is effective only in the supercritical shocks, which have the sonic Mach number M_s > M_crit ≈ 2.3 in the high-beta (β~100) plasma of the ICM, because the Alfven ion cyclotron instability operates and hence multi-scale plasma waves are induced only in such supercritical shocks. Our findings will help to understand the nature of radio relics in galaxy clusters.

• The Plant Pathology Journal
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• 제40권1호
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• pp.83-97
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• 2024

Fusarium graminearum, the causal agent of Fusarium head blight (FHB) in cereal crops, employs the production of sexual fruiting bodies (perithecia) on plant debris as a strategy for overwintering and dissemination. In an artificial condition (e.g., carrot agar medium), the F. graminearum Z3643 strain was capable of producing perithecia predominantly in the central region of the fungal culture where aerial hyphae naturally collapsed. To unravel the intricate relationship between natural aerial hyphae collapse and sexual development in this fungus, we focused on 699 genes differentially expressed during aerial hyphae collapse, with 26 selected for further analysis. Targeted gene deletion and quantitative real-time PCR analyses elucidated the functions of specific genes during natural aerial hyphae collapse and perithecium formation. Furthermore, comparative gene expression analyses between natural collapse and artificial removal conditions reveal distinct temporal profiles, with the latter inducing a more rapid and pronounced response, particularly in MAT gene expression. Notably, FGSG_09210 and FGSG_09896 play crucial roles in sexual development and aerial hyphae growth, respectively. Taken together, it is plausible that if aerial hyphae collapse occurs on plant debris, it may serve as a physical cue for inducing perithecium formation in crop fields, representing a survival strategy for F. graminearum during winter. Insights into the molecular mechanisms underlying aerial hyphae collapse provides offer potential strategies for disease control against FHB caused by F. graminearum.

• 방사성폐기물학회지
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• 제4권1호
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• pp.9-15
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• 2006

결정질 암반에 위치한 가상의 방사성폐기물처분장에 대한 정확한 안전성 평가를 수행하기 위해서는 다공암반으로 대표되는 공학방벽 및 결정질 암반으로 대표되는 자연방벽을 모두 고려한 매질에서의 물질 거동 특성을 정확하게 모사하는 것이 중요하다. 본 논문에서는 단열-다공암반내 유동 및 물질전달의 정확한 해석을 위한 연결망 구축방법에 대하여 서술하였다. 실제 단열암반을 사실적으로 모사하기 위하여 단열 물성자료는 확률밀도함수를 이용하여 생성하였다. 2차원의 사각격자로 모사된 단열암반과 육면체로 모사된 다공암반간 교차선의 원활한 검색을 위하여 단열암반과 연결전 다공암반의 교차면에 가상의 단열암반을 추가적으로 도입하였다. 전체유동경로를 구성하기 저하여 생성된 단열들 간의 교차선을 효율적으로 검색할 수 있는 방법 및 단열암반 및 단열-다공암반간의 연결도를 신속히 확인하는 알고리즘을 제안하였다. 이러한 방법들은 추후 방사성폐기물처분장에서의 단열-다공 암반을 통한 핵종 이동 특성을 모사할 수 있는 수치코드 개발에 많은 도움을 줄 것으로 사료된다.

• 한국균학회지
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• 제25권4호통권83호
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• pp.330-339
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• 1997

식물 병원진균 Botrytis cinerea가 분비하는 polygalacturonase의 동위효소 중에서 endo-type의 polygalacturonase를 Phenyl-Toyopearl column chromatography와 DEAE-, Mono Q-, heparin-high performance liquid chromatography법으로 약 68배 정제하였고 sodium dodecylsulfate(SDS)를 포함하는 polyacrylamide gel electrophoresis로 분석하여 단일 띠를 확인하였다. 정제한 효소의 분자량은 SDS-polyacrylamide gel에서 37 kDa로 측정되었으며 약산성인 조건과 $30^{\circ}C$ 이하에서 안정하였으며 최고 활성은 pH 4.5와 $55^{\circ}C$의 온도에서 관찰되었다. 정제한 효소는 polygalacturonic acid를 endo-type으로 가수분해하였고, polygalacturonic acid에 대한 $K_m$값과 $V_{max}$값은 각각 1.1 mg/ml과 250 nmol/min이었다. N-말단의 아미노산 서열을 결정하여 본 결과, 식물이나 다른 진균류에서 보고된 아미노산 서열과 유사성이 없었다.

• 대한치과기공학회지
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• 제31권3호
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• pp.47-58
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• 2009

Self-leadership means a person's ability to make his thought or behavior in a right way by controlling it himself. Strategies of the same leadership can be largely categorized into three, behavior focused, natural reward and constructive thought strategies. In this study, the foresaid styles of self-leadership strategy are discussed from the perspective of dental lab laboratories' business environment of Gyeongnam region. And accordingly, this researcher examined such strategy styles that dental lab managers, chief technicians and assistant technicians usually have. Results of the study can be summarized as follows. First, out of the self-leadership strategy styles, most remarkably found among the professional of dental technology was constructive thought strategy, followed by behavior-focused and natural reward strategies in order. In general, therefore, the professionals strongly tend to make their thoughts that can a positive effect on their work performance or in a constructive way. In other words, professional dental technicians are more likely to make efforts to persuade or persuade themselves to change their own unreasonable confidence or negative process in more positive way. Second, the extent to which constructive thought strategy is perceived was not different among dental lab managers, chief technicians and assistant technicians. While, behavior-focused and natural reward strategies were found most strongly perceived by dental lab managers, followed by chief and assistant technicians in order. This may be attributed to the fact that the higher professional dental technicians are in position, the higher they are in self-leadership, or in the ability to overcome crises by themselves and make their thought or behavior in a right way. Dental lab managers usually have lots of experiences in relation to behavior-focused or natural reward strategy. Therefore, they are very strongly capable of controlling themselves in order to overcome crises or make their thought or behavior in a right way. In contrast, assistant technicians are still having lots of trials and errors because they are less experienced and skilled. This suggests that chief technicians should make themselves fully capable as a medium that connects between dental lab managers and assistant technicians.

• Toxicological Research
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• 제11권2호
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• pp.241-246
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• 1995

This study was carried out to develop the antitoxic compound about cytotoxicity of cadmium on cultured rat neuroglial cells. These cells divided into 3 groups; control group (medium only) or $MTT_{50}$ group (neuroglial cell, $61{\mu}M$ cadmium) and experimental group ($61{\mu}M$ caffeic acid). Neutral red (NR) and tetrazolium MTT of the colorimetric assay were performed to evaluate the cytotoxicity of cell organelles. The light microscopic study was carried out to morphological changes of cultured rat neuroglical cells. The results indicated that caffeic acid showed detoxification effect on cytotoxicity of cadmium in $61{\mu}M$ concentration. According to the spectroscopic study of 1:1 complex of cadmium and caffeic acid, it showed that this formation of complex eliminated cadmium from cultured rat neurogllal cells.

• Advances in nano research
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• 제9권4호
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• pp.263-276
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• 2020

In this article, the acoustic responses of free vibrated natural fibre-reinforced polymer nanocomposite structure have been investigated first time with the help of commercial package (ANSYS) using the multiphysical modelling approach. The sound relevant data of the polymeric structure is obtained by varying weight fractions of the natural nanofibre within the composite. Firstly, the structural frequencies are obtained through a simulation model prepared in ANSYS and solved through the static structural analysis module. Further, the corresponding sound data within a certain range of frequencies are evaluated by modelling the medium through the boundary element steps with adequate coupling between structure and fluid via LMS Virtual Lab. The simulation model validity has been established by comparing the frequency and sound responses with published results. In addition, sets of experimentation are carried out for the eigenvalue and the sound pressure level for different weight fractions of natural fibre and compared with own simulation data. The experimental frequencies are obtained using own impact type vibration analyzer and recorded through LABVIEW support software. Similarly, the noise data due to the harmonically excited vibrating plate are recorded through the available Array microphone (40 PH and serial no: 190569). The numerical results and subsequent experimental comparison are indicating the comprehensiveness of the presently derived simulation model. Finally, the effects of structural design parameters (thickness ratio, aspect ratio and boundary conditions) on the acoustic behaviour of the natural-fibre reinforced nanocomposite are computed using the present multiphysical model and highlighted the inferences.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.192-195
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• 2002

Effect of aeration rate and agitation speed on cell growth and the production of heteropolysaccharide-7 (PS-7) by Beijerinckia indica was investigated. Aeration rate and agitation speed in a 7L bioreactor ranged from 0.5 to 1.5 vvm and from 300 to 500 rpm, respectively. Higher agitation speed with an aeration rate of 0.5 vvm in the bioreactor resulted in maintenance of higher concentration of dissolved oxygen in the medium, which enhanced the production of PS-7. In this study with a 7L bioreactor, maximal production of PS-7 was 11.0 g/L and its conversion rate from 2% (w/v) glucose was 0.55 when the aeration rate and agitation speed were 1.0 vvm and 500 rpm, respectively. Proper aeration rate and agitation speed might enhance the production of PS-7 as well as reduce the time to reach maximal production.

• 한국잠사곤충학회지
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• 제40권2호
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• pp.111-116
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• 1998

To construct transformed Bm5 cells, Autographa californica nuclear polyhedrosis virus (AcNPV)IE1 gene, an immediate early viral gene was firstly used in this study. AcNPV IE1 gene, which shares on 95.3% uncleotide sequence homology with Bombyx mori nuclear polyhedrosis virus (BmNPV) IE1 gene, was isolated and cloned into pBluescript. Neomycin gene from pKO-neo was inserted under the control of the IE1 promoter to yield pAcIE1-neo. The plasmid pAcIE1-neo was transfected into Bm5 or Sf9 cells, and neomycin-resistant cells were selected in TC100 medium containing 10% fetal bovine serum (FBS) and 1 mg/$m\ell$ G418 for two weeks. Individual clones were picked and each was amplified for further characterization. The genomic DNA from neomycin-resistnt cells was isolated and characterized by PCR using AcNPV IE1 gene-specific primers and by Southern blot analysis using neomycin gene probe. We concluded that AcNPV IE1 gene was functional in B. moridrived Bm5 cells as well as Spodaptera frugiperda-derived Sf9 cells to produce stably-transformed insect cells.