• The Plant Pathology Journal
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• v.31 no.4
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• pp.334-342
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• 2015

Two fumonisin-nonproducing strains of Fusarium verticillioides and their fumonisin producing progenitors were tested for aggressiveness toward maize, sorghum, rice, and beetroot seedlings grown under greenhouse conditions. None of the plants showed obvious disease symptoms after root dip inoculation. Fungal biomass was determined by species-specific real-time PCR. No significant (P = 0.05) differences in systemic colonization were detected between the wild type strains and mutants not producing fumonisins. F. verticillioides was not detected in any of the non-inoculated control plants. The fungus grew from roots to the first two internodes/leaves of maize, rice and beet regardless of fumonisin production. The systemic growth of F. verticillioides in sorghum was limited. The results showed that fumonisin production was not required for the infection of roots of maize, rice and beet by F. verticillioides.

• Journal of Korean Neurosurgical Society
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• v.62 no.3
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• pp.265-271
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• 2019

The expansion and folding of the cerebral cortex occur during brain development and are critical factors that influence cognitive ability and sensorimotor skills. The disruption of cortical growth and folding may cause neurological disorders, resulting in severe intellectual disability and intractable epilepsy in humans. Therefore, understanding the mechanism that regulates cortical growth and folding will be crucial in deciphering the key steps of brain development and finding new therapeutic targets for the congenital anomalies of the cerebral cortex. This review will start with a brief introduction describing the anatomy of the brain cortex, followed by a description of our understanding of the proliferation, differentiation, and migration of neural progenitors and important genes and molecules that are involved in these processes. Finally, various types of disorders that develop due to malformation of the cerebral cortex will be discussed.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.68.2-68.2
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• 2019

Chemical abundance ratios of ultra metal-poor (UMP; [Fe/H] < -4.0) stars can provide important constraints on the early chemical enrichment of the Milky Way (MW), associated with the nucleosynthesis processes that occurred during the evolution of their progenitors, which are presumably the first generation of stars. Despite their importance, only about thirty UMP stars have been discovered thus far. In an effort to identify such stars additionally, we selected UMP candidates from low-resolution (R ~ 2000) spectra from the Sloan Digital Sky Survey and Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST), and obtained with Gemini/GRACES high-resolution (R ~ 40,000) spectra of 15 UMP candidates. In this study, we present the results of the chemical abundance analysis of the UMP candidates. Furthermore, we compare the abundance patterns of our UMP stars with those of various metal-poor stars from literature to understand the early chemical evolution of the MW.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.38.1-38.1
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• 2019

Globular clusters (GCs) are one of the excellent tools to trace the assembly history of their host galaxies. Especially, the ages and abundances of the GCs give important clues about the star formation epochs and merging progenitors. We investigate the stellar population of the GCs in M87 based on a stacking analysis using about 900 MMT/Hectospec spectra of the GCs. We measure the ages, [Z/H], and [a/Fe] from the stacked spectra of the GCs within radial bins based on Lick indices. We find clear radial gradients for [Z/H] and [a/Fe] in the GC system. In addition to the radial trends, we investigate the stellar populations of the GC subgroups divided according to colors, radial velocities, and spatial locations. We discuss the formation history of M87 based on the stellar populations of the GCs.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.51.5-52
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• 2018

The origin of dust in the early Universe has been the subject of considerable debate. Core-collapse supernovae (ccSNe), which occur several million years after their massive progenitors form, could be a major source of that dust, as in the local universe several ccSNe have been observed to be copious dust producers. Here we report nine near-infrared (0.8 - 2.5 micron spectra of the Type II-P SN 2017eaw in NGC 6946, spanning the time interval 22 - 205 days after discovery. The spectra show the onset of CO formation and continuum emission at wavelengths greater than 2.1 micron from newly-formed hot dust, in addition to numerous lines of hydrogen and metals, which reveal the change in ionization as the density of much of the ejecta decreases. The observed CO masses estimated from an LTE model are typically 0.0001 Msun during days 124 - 205, but could be an order of magnitude larger if non-LTE conditions are present in the emitting region. The timing of the appearance of CO is remarkably consistent with chemically controlled dust models of Sarangi & Cherchneff.

• BMB Reports
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• v.56 no.1
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• pp.10-14
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• 2023

Organoids derived from stem cells or organ-specific progenitors are self-organizable, self-renewable, and multicellular three-dimensional (3D) structures that can mimic the function and structure of the derived tissue. Due to such characteristics, organoids are attracting attention as an excellent ex vivo model for drug screening at the stage of drug development. In addition, since the applicability of organoids as therapeutics for tissue regeneration has been embossed, the development of various organoids-based regenerative medicine has been rapidly progressing, reaching the clinical trial stage. In this review, we give a general overview of organoids and describe current status and prospects of organoid-based regenerative medicine, focusing on organoid-based regenerative therapeutics currently under development including clinical trials.

• Molecules and Cells
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• v.45 no.3
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• pp.101-108
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• 2022

Drosophila melanogaster lymph gland, the primary site of hematopoiesis, contains myeloid-like progenitor cells that differentiate into functional hemocytes in the circulation of pupae and adults. Fly hemocytes are dynamic and plastic, and they play diverse roles in the innate immune response and wound healing. Various hematopoietic regulators in the lymph gland ensure the developmental and functional balance between progenitors and mature blood cells. In addition, systemic factors, such as nutrient availability and sensory inputs, integrate environmental variabilities to synchronize the blood development in the lymph gland with larval growth, physiology, and immunity. This review examines the intrinsic and extrinsic factors determining the progenitor states during hemocyte development in the lymph gland and provides new insights for further studies that may extend the frontier of our collective knowledge on hematopoiesis and innate immunity.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.50.1-50.1
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• 2019

Ultra Metal-Poor (UMP; [Fe/H] < -4.0) stars are thought to be true second generation of stars. Thus, the chemistry and kinematics of these stars serve as powerful tools to understand the early evolution of the Milky Way (MW). However, only about 40 of these stars have been discovered thus far. To increase the number of these stars, we selected UMP candidates from low-resolution spectra (R ~ 2000) of the Sloan Digital Sky Survey (SDSS) and Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST), and performed high-resolution (R ~ 40,000) spectroscopic follow-ups with Gemini/GARACES. In this study, we present chemical and kinematic properties of the observed UMP candidates, and infer the nature of their progenitors to trace the chemical enrichment history of the MW.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.65.2-65.2
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• 2020

We present NIR spectroscopic data of young radio quasars obtained from Flamingos-2 (F2) at Gemini-South. The targets are originally selected from Wide-Field Infrared Survey Explorer survey in combination with radio survey data, such as FIRST and NVSS. Our goal is to find observational evidence of jet-driven outflows, which is expected to be present in young luminous quasars from the theoretical studies. While 16 targets were observed with F2, narrow emission lines ([O III] or Hα) were detected in 7 targets. FWHM of the emission lines (up to 2500 km/s) were remarkably broad compared to ordinary quasars, revealing the presence of strong outflows. The black hole mass estimated from Eddington limit ranges from ~108 to 109 solar mass, indicating that the target quasars are likely to be progenitors of massive galaxies. Finally, we present the comparisons between the outflow velocity and the physical properties of radio jets derived from the VLA radio imaging data, in order to investigate the physical connection between the ionized outflows and radio jets.

• Journal of Life Science
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• v.23 no.5
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• pp.710-720
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• 2013

Radiotherapy is commonly used in treating many kinds of cancers which cannot be cured by other therapeutic strategies. However, radiotherapy also induces the damages on the normal tissues. Radiation-induced fibrosis is frequently observed in the patients undergoing radiotherapy, and becomes a major obstacle in the treatment of intrahepatic cancer. Hedgehog (Hh) that is an essential in the liver formation during embryogenesis is not detected in the healthy liver, but activated and modulates the repair process in damaged livers in adult. The expression of Hh increases with the degree of liver damage, regulating the proliferation of hepatic progenitors and hepatic stellate cells (HSC). In addition, Hh induces epithelial-to-mesencymal transition (EMT) and activation of myofibroblasts. In the irradiated livers, up-regulated expression of Hh signaling was associated with proliferation of progenitors, EMT induction, and increased fibrosis. Female-specific expression of Hh leaded to the expansion of progenitors and the accumulation of collagen in the irradiated livers of female mice, indicating that gender disparity in Hh expression may be related with radiation-susceptibility in female. Hence, Hh signaling becomes a novel object of studies for fibrogenesis induced by radiation. However, the absence of the established experimental animal models showing the similar physiopathology with human liver diseases and fibrosis-favorable microenvironment hamper the studies for the radiation-induced fibrosis, providing a few descriptive results. Therefore, further research on the association of Hh with radiation-induced fibrosis can identify the cell and tissue-specific effects of Hh and provides the basic knowledge for underlying mechanisms, contributing to developing therapies for preventing the radiation-induced fibrosis.