• 제목/요약/키워드: Cluster Center

검색결과 1,188건 처리시간 0.028초

화총내 착과위치에 따른 '신고' 배 (Pyrus pyrifolia Nakai) 과실의 품질비교 (Comparison of Fruit Quality among Fruits Set on Various Position within Cluster in 'Niitaka' Pears)

  • 이욱용;오경영;심훈기;이혁재;황용수;천종필
    • 농업과학연구
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    • 제37권1호
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    • pp.13-18
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    • 2010
  • In order to prepare the technical fundamental in production of premium quality fruits of 'Niitaka' pears, we compared the quality parameters and storability of the fruits that had various fruit set position in a cluster. The fruits set on $4^{th}$ from basal part in fruit cluster had the largest fruit size. The weight of fruits set on the higher position than $4^{th}$ from basal part in fruit cluster showed decreasing tendency. The production rates of marketable fruits which had 500g to 899g in weight were the high in $3-5^{th}$ from basal part in cluster than those in other position. The differences of fruit height and diameter which represent balanced fruit shape also showed less difference in the fruits set on $4-5^{th}$ from basal part in cluster than the fruits set closely on basal part in cluster. The fruits set on $3-4^{th}$ from basal part in cluster showed lower rate in incidence of core breakdown and pithiness disorder during 4 months of cold storage than those on the closer position to basal part in cluster.

Single-Cell RNA Sequencing of Bone Marrow Mesenchymal Stem Cells from the Elderly People

  • Dezhou Zhu;Jie Gao;Chengxuan Tang;Zheng Xu;Tiansheng Sun
    • International Journal of Stem Cells
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    • 제15권2호
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    • pp.173-182
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    • 2022
  • Background and Objectives: Bone marrow mesenchymal stem cells (BMSCs) show considerable promise in regenerative medicine. Many studies demonstrated that BMSCs cultured in vitro were highly heterogeneous and composed of diverse cell subpopulations, which may be the basis of their multiple biological characteristics. However, the exact cell subpopulations that make up BMSCs are still unknown. Methods and Results: In this study, we used single-cell RNA sequencing (scRNA-Seq) to divide 6,514 BMSCs into three clusters. The number and corresponding proportion of cells in clusters 1 to 3 were 3,766 (57.81%), 1,720 (26.40%), and 1,028 (15.78%). The gene expression profile and function of the cells in the same cluster were similar. The vast majority of cells expressed the markers defining BMSCs by flow cytometry and gene expression analysis. Each cluster had at least 20 differentially expressed genes (DEGs). We conducted Gene Ontology enrichment analysis on the top 20 DEGs of each cluster and found that the three clusters had different functions, which were related to self-renewal, multilineage differentiation and cytokine secretion, respectively. In addition, the function of the top 20 DEGs of each cluster was checked by the National Center for Biotechnology Information gene database to further verify our hypothesis. Conclusions: This study indicated that scRNA-Seq can be used to divide BMSCs into different subpopulations, demonstrating the heterogeneity of BMSCs.

The Globular Cluster NGC 6273: Another Candidate for the Milky Way Building Blocks

  • Lim, Dongwook;Han, Sang-Il;Lee, Young-Wook
    • 천문학회보
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    • 제40권2호
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    • pp.40.2-40.2
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    • 2015
  • In our recent investigation (Lim et al. 2015), we have shown that the combination of narrow-band Ca photometry and low-resolution spectroscopy can effectively search for globular clusters (GCs) with supernovae (SNe) enrichments. We apply this technique to the metal-poor bulge GC NGC 6273 and find two distinct subpopulations having different light and heavy element abundances. Our result suggests that NGC 6273 was massive enough to retain SNe ejecta, which would place this cluster in the growing group of GCs with Galactic building block characteristics, such as ${\omega}$ Centauri and M22.

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ON THE VARIABILITY OF BLUE STRAGGLER STARS IN THE GLOBULAR CLUSTER M53

  • Rey, Soo-Chang;Lee, Young-Wook;Byun, Yong-Ik;Chun, Mun-Suk
    • Journal of Astronomy and Space Sciences
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    • 제15권1호
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    • pp.39-48
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    • 1998
  • We present the results of a search for photometric variable blue straggler stars(BSSs) in the globular cluster M53. Six of 151 probable BSSs are identified as variable candidates based on the robust variable star detection technique of Welch & Stetson (1993). Most variable BSS candidates appear to occupy the instability strip in the color-magnitude deagram, and they appear to have visual light amplitudes of 0.2 mag-0.3 mag. Further observations are required, however, to resolve the natrue of variabil-ity between pulsating stars and eclipsing binaries for these variable BSS candidates.

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THE GROWTH OF A PRIMORDIAL BLACK HOLE AT THE CENTER OF A STAR

  • Park, Seok-Jae
    • 천문학회지
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    • 제23권2호
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    • pp.116-121
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    • 1990
  • It has been suggested that there could be a large number of primordial black holes which were formed in the early universe. We analyze the growth of such a primordial black hole following two different accretion rates - the Eddington accretion rate and the Bondi accretion rate - at the center of a host star like the sun. We find that a primordial black hole with M < ${\sim}10^{17}\;g$ cannot substantially grow in any case throughout the lifetime of a host star. If M > ${\sim}10^{17}\;g$, the evolution of a host star depends entirely on the mode of accretion, but it ends as a black hole in either case. Since more stars may have primordial black holes at the center of a galaxy this may result in a cluster of such black holes, and the cluster may eventually collapse to produce a single supermassive black hole.

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