• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.255-259
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• 2015

Recent narrow-band Ca photometry discovered two distinct red giant branch (RGB) populations in some massive globular clusters (GCs) including M22, NGC 1851, and NGC 288. In order to investigate the differences in light/heavy elements abundances between the two subpopulations, we have performed low-resolution spectroscopy for stars on the two RGBs in these GCs. We find a significant difference (more than $4{\sigma}$) in calcium abundance from the spectroscopic HK' index for both M22 and NGC 1851. We also find a more than $8{\sigma}$ difference in CN band strength between the Ca-strong and Ca-weak subpopulations. For NGC 288, however, we detect the presence of a large difference only in the CN strength. The calcium abundances of the two subpopulations in this GC are identical within errors. We also find interesting differences in CN-CH relations among these GCs. While CN and CH indices are correlated in M22, they show an anti-correlation in NGC 288. However, NGC 1851 shows no difference in CH between two groups of stars having different CN strengths. The CN bimodality in these GCs could be explained by pollution from intermediate-mass asymptotic giant branch stars and/or fast-rotating massive stars. For the presence or absence of calcium bimodality and the differences in CN-CH relations, we suggest these would be best explained by how strongly type II supernovae enrichment has contributed to the chemical evolutions of these GCs.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.6
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• pp.542-547
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• 2012

Until recently, most of GCS(Ground Control Software) has been required to visualize attitude, position, status of vehicle and to transmit control and mission commands for a single UAV(Unmanned Aerial Vehicle). However, the GCS needs to expand its functions to handle more complex situations. Simultaneous operation of multiple UAVs is emerging as a new practice. Hence, we set up requirements for operation of multiple UAVs and suggest the architecture of GCS that satisfy the requirements. In this study, we analyze the upper requirements and define the total structure of GCS at first. Then we design the inner structure for requirements in detail. Finally, we verify the functions of GCS on PILS(Processor In the Loop Simulation) System.

• Animal Bioscience
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• v.34 no.11
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• pp.1766-1775
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• 2021

Objective: The oxidative stress status and changes of chicken ovary tissue after shading were studied, to determine the mechanism of the effect of shading on follicular development. Methods: Twenty healthy laying hens (40 weeks old) with uniform body weight and the same laying rate were randomly divided into two groups (the shading group and normal light group). In the shading group, the cage was covered to reduce the light intensity inside the cage to 0 without affecting ventilation or food intake. The normal lighting group received no additional treatment. After 7 days of shading, oxidative stress related indicators and gene expression were detected. Results: Analysis of paraffin and ultrathin sections showed that apoptosis of ovarian granulosa cells (GCs) increased significantly after light shading. Enzyme linked immunosorbent assay results revealed that the levels of total antioxidant capacity, malondialdehyde, superoxide dismutase (SOD), glutathione, catalase (CAT), and other substances in the sera, livers, ovaries, and follicular GCs of laying hens increased significantly after shading for 7 days; and reactive oxygen species (ROS) levels in the livers of laying hens also increased significantly. ROS in the serum, ovarian and GCs also increased. After shading for 7 days, the levels of 8-hydroxy-2 deoxyguanosine in the sera and ovarian tissues of laying hens increased significantly. Cell counting kit-8 detection showed that the proliferation activity of GCs in layer follicles decreased after shading for 7 days; the expression level of the anti-apoptotic gene B-cell lymphoma-2 in ovarian tissue and follicular GCs was significantly reduced, and the expression levels of pro-apoptotic caspase 3 (casp3), and SOD, glutathione peroxidase 2 (GPX2), and CAT were all significantly increased. Conclusion: Oxidative stress induced by shading light has a serious inhibitory effect on follicular development during reproduction in laying hens.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.37.2-37.2
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• 2019

Recent investigations of the double red clump in the color-magnitude diagram of the Milky Way bulge cast serious doubts on the structure and formation origin of the outer bulge. Unlike previous interpretation based on an X-shaped bulge, stellar evolution models and CN-band observations have suggested that this feature is another manifestation of the multiple stellar population phenomenon observed in globular clusters (GCs). This new scenario requires a significant fraction of the outer bulge stars with chemical patterns uniquely observed in GCs. Here we show from homogeneous high-quality spectroscopic data that the red giant branch stars in the outer bulge ($>5.5^{\circ}$ from the Galactic center) are clearly divided into two groups according to Na abundance in the [Na/Fe] - [Fe/H] plane. The Na-rich stars are also enhanced in Al, while the differences in O and Mg are not observed between the two Na groups. The population ratio and the Na and Al differences between the two groups are also comparable with those observed in metal-rich GCs. Since these chemical patterns and characteristics are only explained by stars originated in GCs, this is compelling evidence that the outer bulge was mostly assembled from disrupted proto-GCs in the early history of the Milky Way. We will also discuss the implications of this result on the formation of the early-type galaxies in general.

• Journal of Yeungnam Medical Science
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• v.12 no.1
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• pp.32-47
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• 1995

Glutathione(GSH) has a very important role in detoxification of cells and is closely related to antitumor drug-resistance of cancer cells. In order to evaluate the importance of glutathione metabolism in the drug-resistant cancer cells, the concentration of celluar GSH and activities of ${\gamma}$-glutamylcysteine synthetase(GCS), ${\gamma}$-glutamyl transpeptidase (GGT) and glutathione S-transferases(GST) in the adriamycin, vincristine, or cisplatin resistant L1210 (L1210AdR, L1210VcR, or L1210Cis) sublines were measured. Expression and amplification of GCS, GGT, and GST-${\pi}$ genes were also observed in the parent Ll210 and the drug-resistant Ll210 sublines. The concentration of GSH was increased 5.34 fold in L1210Cis, 2.83 fold in L1210VcR, and 1.78 fold in L1210AdR, compared to L1210. The activities of GCS and GGT were increased in drug-resistant L1210 sublines. The GST activity was increased in L1210VcR and L1210Cis but decreased in L1210AdR compared to Ll210. Expression of GCS, GGT, and GST-${\pi}$ genes were increased in the resistant L1210 sublines compare to the parent L1210 in northern blot analyses. Overexpression of GCS, GGT, and GST-${\pi}$ were observed in the resistant sublines, and the increases of the concentration of glutathione and the activities of GCS and GGT in the resistant sublines may be involved in a part of the drug-resistance in the resistant sublines.

• Journal of Microbiology
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• v.41 no.3
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• pp.248-251
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• 2003

Glutathione (GSH) is an important factor in determining tolerance against oxidative stress in living organisms. It is synthesized in two sequential reactions catalyzed by ${\gamma}$-glutamylcysteine synthetase (GCS) and glutathione synthetase (GS) in the presence of ATP. In this work, the effects of three different oxidative stresses were examined on GSH content and GSH-related enzyme activities in the fission yeast Schizosaccharomyces pombe. GSH content in S. pombe was significantly enhanced by treatment with hydrogen peroxide, ${\beta}$-naphthoflavone (BNF) and tert-butylhydroquinone (BHQ). Simultaneously, they greatly induced GCS and GS activity. However, they did not have any effects on glutathione reductase activity. These results suggest that GCS and GS activities in S. pombe are up-regulated by oxidative stress.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.78.1-78.1
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• 2015

Recent studies for the Milky Way globular clusters (GCs) have reported that most of them host multiple stellar populations. However, only a few GCs have shown abundance variations in heavy elements such as iron and calcium. These GCs, as galaxy building blocks, are important to understand the formation of the Milky Way in hierarchical merging paradigm. In this study, we report our discovery from the Ca narrow-band photometry and low-resolution spectroscopy that NGC 6273 is a new Milky Way building block candidate.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.58.3-58.3
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• 2015

Blue Straggler Stars (BSSs), kind of unusual main sequence stars, are the brighter and bluer stars than the main sequence turn off (MSTS) stars in coeval clusters. Since the first detection in globular clusters (GCs), BSSs have been shown to reveal an anti-correlation between the luminosity of their host star cluster and the number of BSSs in the cluster. Further, conclusions based on this result can be expanded to the open clusters. BSSs seem to play an important role in GCs according to the relation between the dynamical time scale of GCs and the number of BSSs along the cluster radius. This relation, however, remains to be verified in open clusters, In this study, we divide open clusters by the existence of BSSs into two groups. Then we compare parameters between these groups to specify the role of BSSs in open clusters.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.64.2-64.2
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• 2013

As more spectroscopic observations accumulate, it becomes evident that there are variations in light elements, such as C, N, O, and Na, between the sub-populations in most globular clusters (GC) in the Milky Way. We have constructed a new set of isochrones and horizontal branch evolutionary tracks with enhanced Nitrogen and depleted Oxygen to study their effects on the evolution of stars in GCs. From these results, we found that their effects on the evolution in color-magnitude diagram are significant in determining the age of GCs. In order to reflect these effects in the construction of population models for GCs, we have expanded the parameter space of Yonsei-Yale Isochrones and HB evolutionary tracks by introducing abundance enhancements of N for various global metal abundances and helium contents. In this paper, we will present our preliminary results from these calculations.

• Journal of Korean Neurosurgical Society
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• v.37 no.6
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• pp.432-435
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• 2005

Objective: This study was performed to evaluate the usefulness of early operation in children with traumatic subdural hygroma. Methods: The subjects were nine patients (Glasgow coma scale (GCS) score was below 10 and age was below 10 years old) who developed subdural hygroma after trauma between January 2000 to December 2002. Subduroperitoneal shunt was performed in one group and not performed in the other group. We analyzed the GCS score on admission and at 1 year after operation. Overall clinical results were evaluated retrospectively. Results: Patients who underwent operation exhibited higher GCS scores at 1 year after trauma compared to those in the patients who were treated by conservative therapy(p<0.05). Conclusion: The early operation could be an effective treatment to children with subdural hygroma who showed delayed improvement of consciousness and to patients with hygroma that didn't decrease or was above moderate amount.