• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.76-76
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• 2013

The current hierarchical model of galaxy formation predicts that galaxy halos contain merger relics in the form of long stellar streams. In order to find stellar substructures in galaxy, we focused our investigation on the stellar spatial density around globular clusters and on the quantitative properties of the evolved sequences in the color-magnitude diagrams (CMDs). First, we investigated the spatial configuration of stars around five metal-poor globular clusters in halo region (M15, M30, M53, NGC 5053, and NGC 5466) and one metal-poor globular cluster in bulge region (NGC 6626). Our findings indicate that all of these globular clusters show strong evidence of extratidal features in the form of extended tidal tails around the clusters. The orientations of the extratidal features show the signatures of tidal tails tracing the clusters' orbits and the effects of dynamical interactions with the galaxy. These features were also confirmed by the radial surface density profiles and azimuthal number density profiles. Our results suggest that these six globular clusters are potentially associated with the satellite galaxies merged into the Milky Way. Second, we derived the morphological parameters of the red giant branch (RGB) from the near-infrared CMDs of 12 metal-poor globular clusters in the Galactic bulge. The photometric RGB shape indices such as colors at fixed magnitudes, magnitudes at fixed colors, and the RGB slope were measured for each cluster. The magnitudes of the RGB bump and tip were also estimated. The derived RGB parameters were used to examine the overall behavior of the RGB morphology as a function of cluster metallicity. The behavior of the RGB shape parameters was also compared with the previous observational calibration relation and theoretical predictions of the Yonsei-Yale isochrones. Our results of studies for stellar spatial distribution around globular clusters and the morphological properties of RGB stars in globular clusters could add further observational evidence of merging scenario of galaxy formation.

• The KIPS Transactions:PartB
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• v.19B no.3
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• pp.195-200
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• 2012

In Korean, spelling change in various forms must be recovered into base forms in morphological analysis as well as part-of-speech (POS) tagging is difficult without morphological analysis because Korean is agglutinative. This is one of notorious problems in Korean morphological analysis and has been solved by morpheme recovery rules, which generate morphological ambiguity resolved by POS tagging. In this paper, we propose a morpheme recovery scheme based on machine learning methods like Na$\ddot{i}$ve Bayes models. Input features of the models are the surrounding context of the syllable which the spelling change is occurred and categories of the models are the recovered syllables. The POS tagging system with the proposed model has demonstrated the $F_1$-score of 97.5% for the ETRI tree-tagged corpus. Thus it can be decided that the proposed model is very useful to handle morpheme recovery in Korean.

• Journal of Korea Multimedia Society
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• v.10 no.7
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• pp.846-855
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• 2007

Significant feature extraction in cancer cell image analysis is an important process for grading cell carcinoma. In this study, we propose a method for 3D quantitative analysis of cell nuclei based upon digital image cytometry. First, we acquired volumetric renal cell carcinoma data for each grade using confocal laser scanning microscopy and segmented cell nuclei employing color features based upon a supervised teaming scheme. For 3D visualization, we used a contour-based method for surface rendering and a 3D texture mapping method for volume rendering. We then defined and extracted the 3D morphological features of cell nuclei. To evaluate what quantitative features of 3D analysis could contribute to diagnostic information, we analyzed the statistical significance of the extracted 3D features in each grade using an analysis of variance (ANOVA). Finally, we compared the 2D with the 3D features of cell nuclei and analyzed the correlations between them. We found statistically significant correlations between nuclear grade and 3D morphological features. The proposed method has potential for use as fundamental research in developing a new nuclear grading system for accurate diagnosis and prediction of prognosis.

• Korean Journal of Veterinary Research
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• v.37 no.2
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• pp.245-252
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• 1997

To investigate morphological changes in the exocrine pancreas of chicken after pancreatic duct ligation, experimental animals were subdivided to control, 12 hours, 1 day, 2 days, 4 days, 7 days and 10 days groupes and all of three pancreatic ducts of chicken were ligated by surgical procedure and then the morphological changes were observed. In pancreatic ducts, once for a while the ducts were dilated on 12 hours after pancreatic duct ligation and then they were obstructed because of proliferated epithelial cells and connective tissues in pancreatic duct. Marginal dissociation of acini was detected in 12 hours after pancreatic duct ligation and then dissociation of acini was increased with time and finally in 4 days after pancreatic duct ligation the acini showed completely dissociation except periductular regions and around pancreatic islets. Most of dissociated acini cells showed marginal condensation of nuclear chromatin and atropy of cytoplasm, namely, apoptotic features were detected in dissociated acinar cells. Interacinar spaces of dissociated acinar regions were dilated and fulfilled with increased connective tissue and in 4 days after pancreatic duct ligation, deposition of lymphocytes and hemocytes was occurred.

• Korean Journal of Poultry Science
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• v.32 no.2
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• pp.97-100
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• 2005

Mast cells have been studied extensively in various animals including rats and mice, whereas little is known the morphological data about pheasant mast cells. Here, morphological features of Korean pheasant mast cells are described in this study using light and electron microscopes. For light microscopy, mast cells had many metachromatic granules stained with toluidine blue in the cytoplasm. The fixation with $10\%$ neutral buffered formalin blocked staining of most mast cells but a modified Karnovsky solution proved to be a good fixative. In Korean pheasants, toluidine blue stained more mast cells than did alcian blue. For electron microscopy, the mast cells of the Korean pheasant were round, oval, spindle-like and irregular form and occasionally had a few short cytoplasmic processes. These cells had membrane-bounded granules and poorly developed organells. Some granules in the cytoplasm of the mast cells had bilayer membrane. Most granules were round shape and the membrane of several granules was concave or convex. The granules were composed of three parts, homogenous, particulate and reticular pattern.

• The Korean Journal of Mycology
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• v.46 no.1
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• pp.9-21
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• 2018

Seven unrecorded species in the phylum Ascomycota, Emericellopsis pallida (KNU16-167), Scedosporium aurantiacum (KNU16-190), Duddingtonia flagrans (KNU16-279), Bionectria rossmaniae (KNU16-309), Exophiala xenobiotica (KNU16-79), Pseudocercosporella fraxini (KNU16-102), and Stachybotrys sansevieriae (KNU16-141), were isolated in 2016 from field soils collected from various locations in Korea. All of the species were identified and described based on morphological characteristics and rDNA internal transcribed spacer sequence data. Morphological features of these fungi were examined on potato dextrose agar, oatmeal agar, malt extract agar, Czapek yeast extract agar, and yeast extract sucrose agar. Full descriptions and illustrations of their morphological characteristics are provided.

• Mycobiology
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• v.45 no.4
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• pp.327-337
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• 2017

Three new records of Ascomycota species (Chaetomium acropullum, Phialemonium globosum, Phialemonium atrogriseum) from field soils in Korea are presented in this study. These newly discovered fungal isolates were isolated from field soils from various places across Gyeongnam, Korea in 2016. All the isolates were identified and described based on morphological characteristics, and rDNA internal transcribed spacer and ${\beta}$-tubulin gene sequence data. Morphological features of these fungal species were studied on different agar media: potato dextrose agar, oatmeal agar, malt extract agar, Czapek yeast extract agar, and yeast extract sucrose agar. Full description and illustrations of their morphological characters are provided. These fungal species have not officially been previously reported in Korea.

• ALGAE
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• v.35 no.1
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• pp.17-32
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• 2020

Asterochloris is one of the most common genera of lichen phycobionts in Trebouxiophyceae. Asterochloris phycobionts associated with the lichenized fungi Cladonia and Stereocaulon in King George Island (Antarctica) and Morro Chico (Chile), were isolated and then used to establish clonal cultures. To understand the phylogenetic relationships and species diversity of Antarctic Asterochloris species, molecular and morphological data were analyzed by using three microscopy techniques (light, confocal laser and transmission electron) and a multi-locus phylogeny with data from the nuclear-encoded internal transcribed spacer (ITS) rDNA and the actin and plastid-encoded ribulose bisphosphate carboxylase large chain (rbcL) coding genes. Morphological data of three Antarctic strains showed significant species-specific features in chloroplast while molecular data segregated the taxa into distinct three clades as well. Each species had unique molecular signatures that could be found in secondary structures of the ITS1 and ITS2. The species diversity of Antarctic Asterochloris was represented by six taxa, namely, A. glomerata, A. italiana, A. sejongensis, and three new species (A. antarctica, A. pseudoirregularis, A. stereocaulonicola).

• ALGAE
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• v.21 no.2
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• pp.169-174
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• 2006

We have cultured more than 100 Arctic and Antarctic cryophilic microalgal strains in KOPRI culture collections of polar microorganisms (KCCPM). Among them, we tried to identify an Antarctic strain, KOPRI AnM0008 by morphological and molecular analysis. Nuclear SSU rDNA and plastid rbcL sequences were used to identify the strain. It was identified as Porosira pseudodenticulata based on SSU sequence data showing 99% identity with GenBank X85398. This result was supported by morphological features like solitary labiate process, external foramina and internal cribra by optical and scanning electron microscope. Morphological identification and molecular analysis on polar cryophilic microalgae will be accomplished to construct the databases for KCCPM.

• Journal of agriculture & life science
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• v.45 no.6
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• pp.1-7
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• 2011

This work was performed to confirm the molecular discrimination through the nrITS1 sequences among 3 taxa of Scirpus L. sensu lato (s.l.) species. S. planiculmis represented only 2 base sequence variations with S. maritimus in spite that they showed different morphological features. The nucleotide sequences of the ITS1 region from S. planiculmis were shown to have 99.1% homology with S. maritimus and 60.4% homology with S. triqueter. Although the morphology of S. planiculmis is similar with S. triqueter, molecular basis of the size and sequences on ITS1 region were shown to have distinctive differences. For divergency investigation on same sites and metapopulation, sequencing was conducted on ITS1 region with partial 5.8S and 18S regions. All plants of each species collected at the same site had identical band size pattern and sequences. Intraspecific molecular divergency was not identified in spite that these species live in different wetland sites. The ITS1 sequences described here provided a powerful genetic tool for phylogenetic studies which was difficult by morphological identification as high rate of morphological plasticity.