• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.40.2-40.2
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• 2017

At local, majority of galaxies in the dense environment, such as galaxy cluster, are red and quiescent with little star-formation (SF) activity. However, a different picture emerges as we go to high redshift: (1) there exist non-negligible fraction of galaxies still forming stars actively even in dense environment, and (2) there is a significant cluster-by-cluster variation in the SF properties, such as quiescent galaxy fraction. In this presentation, we show the results of our study about the variation of quiescent galaxy fraction among high-redshift (z~1) galaxy clusters, based on the multi-object spectroscopic (MOS) observation with IMACS on the Magellan telescope. Our main result is that galaxy clusters which are connected with significant large-scale structure (LSS), well beyond the cluster scale, are more active in their SF activity, i.e., the quiescent galaxy fraction for these clusters is lower compared to the clusters which are detached from LSS.

• The Bulletin of The Korean Astronomical Society
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• v.34 no.1
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• pp.151.1-151.1
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• 2009

• Molecules and Cells
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• v.45 no.10
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• pp.695-701
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• 2022

Homeostatic regulation of meristematic stem cells accomplished by maintaining a balance between stem cell self-renewal and differentiation is critical for proper plant growth and development. The quiescent center (QC) regulates root apical meristem homeostasis by maintaining stem cell fate during plant root development. Cell cycle checkpoints, such as anaphase promoting complex/cyclosome/cell cycle switch 52 A2 (APC/C^CCS52A2), strictly control the low proliferation rate of QC cells. Although APC/C^CCS52A2 plays a critical role in maintaining QC cell division, the molecular mechanism that regulates its activity remains largely unknown. Here, we identified SCF^FBS1, a ubiquitin E3 ligase, as a key regulator of QC cell division through the direct proteolysis of CCS52A2. FBS1 activity is positively associated with QC cell division and CCS52A2 proteolysis. FBS1 overexpression or ccs52a2-1 knockout consistently resulted in abnormal root development, characterized by root growth inhibition and low mitotic activity in the meristematic zone. Loss-of-function mutation of FBS1, on the other hand, resulted in low QC cell division, extremely low WOX5 expression, and rapid root growth. The 26S proteasome-mediated degradation of CCS52A2 was facilitated by its direct interaction with FBS1. The FBS1 genetically interacted with APC/C^CCS52A2-ERF115-PSKR1 signaling module for QC division. Thus, our findings establish SCF^FBS1-mediated CCS52A2 proteolysis as the molecular mechanism for controlling QC cell division in plants.

• Bulletin of the Korean Space Science Society
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• 2005.04a
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• pp.31-31
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• 2005

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.530-532
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• 2002

We have developed a low-power, high slew-rate OP-AMP for large size and high resolution TFT-LCDs which have 8${\mu}$A quiescent current with settling time less than 6${\mu}$sec. The proposed OP-AMP contains newly developed the driving circuit of class-AB output stage which can achieve a low quiescent current less than 8${\mu}$A and a slew-rate higher than 3.14V/${\mu}$sec.

• Journal of The Korean Astronomical Society
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• v.23 no.1
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• pp.71-82
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• 1990

Theoretical calculations of the combined radiative transfer and statistical equilibrium equation including the charge-particle conservations have been earned out for a multilevel hydrogen atom in quiescent prominences. Cool and dense models show the steep changes of population and radiation field in the vicinity of the surface, while these physical quantities remain unchanged for models with temperature of 7,300K, regardless of total densities. Ionization rate of hydrogen atom related with metallic line formation varies in considerable amounts from the surface to the center of model prominences cooler than 6,300K. However, such cool models cannot release enough hydrogen line emissions to explain observed intensities. Prominence models with a temperature higher than 8,000K can yield the centrally reversed Lyman line profiles confirmed by satellite EUV observations. We find that queiscent prominence with a density between $2{\times}10^{11}$ and $10^{12}cm^{-3}$ should be in temperature range between 6,300K and 8,300K, in order to explain consistently observed H alpha, beta line emissions and $n_p/n_l$ ratio.

• Journal of Life Science
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• v.17 no.3 s.83
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• pp.381-385
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• 2007

Facilitates chromatin transcription (FACT) is a chromatin-specific elongation factor required for transcription of chromatin templates in vivo and in vitro. FACT consists of human homologue of the Saccharomyces cerevisiae Spt16/Cdc68 protein (hSpt16) and the high mobility group-1-like protein structure-specific recognition protein-1 (SSRP-1). Here we show that the protein level of hSpt16 is massively down-regulated in quiescent T98C cells using both immunofluorescence and western blot analysis. In contrast, we observe high level of the hspt16 expression in the proliferative T98G cells. Interestingly, the expression of SSRP-1 is not altered in both quiescent and proliferative states. Taken together, our findings implicate that the expression of hSpt16 is associated with the proliferative state and can be used as a proliferation marker.

• The Journal of the Acoustical Society of Korea
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• v.23 no.5
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• pp.340-352
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• 2004

Acoustic streaming induced by the microscopic longitudinal ultrasonic vibration at 28.5 ㎑ is visualized between the quiescent glass plate and ultrasonic vibrator by particle imaging velocimetry(PIV) using laser. To investigate the augmentation of air flow velocity of acoustic streaming. the velocity variations of air streaming between the stationary plate and ultrasonic vibrator are measured in real-time. It is experimentally investigated that the magnitude of the acoustic streaming dependent upon the gap between the ultrasonic vibrator and stationary p1ate results in the variations of the average velocity fields as a outcome of the bulk air flow caused by the ultrasonic vibration. In addition. maximum acoustic streaming velocity exists at resonant gap. 18mm that is one of the resonant gaps (H=18, 24, 30, 36㎜) at which resonance occurs. The variation of the local maximum turbulent intensity with axial direction appear to reveal the value of 8%∼70% dependent upon the gap between the quiescent glass plate and ultrasonic vibrator. Shearstress is also maximized at the center region of the vibrator and the vorticity is also maximum and minimum in the neighborhood of the center of the vibrator at which the local maximum turbulent intensity and shear stress exist.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.36.1-36.1
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• 2018

Star formation activity of galaxies, along with color and morphology, show significant environmental dependence in local universe, where galaxies in dense environment tend to be more quiescent and redder. However, many studies show that such environmental dependence does not continue at higher redshifts beyond z~1. The question of how the environmental dependence of galactic properties have developed over time is crucial to understanding cosmic galactic evolution. By combining data from Canada-France-Hawaii Telescope Legacy Survey(CFHTLS), Infrared Medium-Deep Survey(IMS), and other surveys, the photometric redshifts of galaxies in CFHTLS W2 field were estimated by fitting spectral energy distribution. The distribution of galaxies was mapped in redshift bins of 0.05 interval from 0.6 to 1.4. For each redshift bin, the number density was mapped. The galaxies in high density regions were grouped into clusters using friend-of-friend method. The color of galaxies were analyzed to study the correlation with redshift as well as environmental difference between field galaxies and cluster member galaxies.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.24 no.3
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• pp.31-37
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• 1998

Soybeans are one of the major crops for human food resource; protein, lipid, and carbohydrate. In these days, they are widely using for cosmetics to supply phospholipid; natural surfactant. In this study we used black soybean seed in korea and observed many kinds of biochemical constituents; isoflavone, melatonin, crisantemine and calcium in ethanol extract. Also, its extract (we named it Flatonin) has been demonstrated that korean black soybean seed is able to stimulate the proliferation of NIH 373 cells and increase the production of type III collagen in NIH 373 and Malme-3 (human skin fibroblast) cells. The addition of korean black soybean to quiescent NIH 373 cells resulted in an increase of proliferation which was assayed by MTF method. The maximum effect of korean black soybean was detected in 0.4％ korean black soybean treated cells which was comparable to that of 5% serum(96％ of 5％ serum effect). The addition of korean black soybean to NIH 373 and Malme-3 cells also increased the production of type III collagen in both cells. These results indicate that korean black soybean may enhance the repair process after injury and prevent aging processes in connective tissues.