• Clinical and Experimental Reproductive Medicine
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• v.45 no.2
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• pp.75-81
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• 2018

Objective: Recapitulation of the spermatogenesis process in vitro is a tool for studying the biology of germ cells, and may lead to promising therapeutic strategies in the future. In this study, we attempted to transdifferentiate Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs) into male germ cells using all-trans retinoic acid and Sertoli cell-conditioned medium. Methods: Human WJ-MSCs were propagated by the explant culture method, and cells at the second passage were induced with differentiation medium containing all-trans retinoic acid for 2 weeks. Putative germ cells were cultured with Sertoli cell-conditioned medium at $36^{\circ}C$ for 3 more weeks. Results: The gene expression profile was consistent with the stage-specific development of germ cells. The expression of Oct4 and Plzf (early germ cell markers) was diminished, while Stra8 (a premeiotic marker), Scp3 (a meiotic marker), and Acr and Prm1 (postmeiotic markers) were upregulated during the induction period. In morphological studies, approximately 5% of the cells were secondary spermatocytes that had completed two stages of acrosome formation (the Golgi phase and the cap phase). A few spermatid-like cells that had undergone the initial stage of tail formation were also noted. Conclusion: Human WJ-MSCs can be transdifferentiated into more advanced stages of germ cells by a simple two-step induction protocol using retinoic acid and Sertoli cell-conditioned medium.

• Journal of Ocean Engineering and Technology
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• v.12 no.2 s.28
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• pp.79-86
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• 1998

A three-dimensional WIG (Wing In Ground effect) moving above free surface is numerically studied by means of finite difference techniques. The air flow field around the WIG is analyzed by MAC (Marker & Cell) method, and interactions between WIG and the free surface are appeared as the variation of pressure distribution acting on the free surface. To analyze the wavemaking phenomena by those pressure distributions, the NS (Navier-Stokes) solver is employed in which nonlinearities of the free surface conditions can be included. Through the numerical simulation, Cp values and lift/drag ratio are carefully reviewed by changing the height/chord ratio. The section shape of model is NACA0012 with the span/chord ratio of 3.0. Through computational results, it is confirmed that the effect of free surface is small enough to treat it as a rigid wavy wall.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.10 no.3
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• pp.185-219
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• 1981

To analyze two dimensional incompressible laminar natural convection in a rectangular enclosure heated from below and cooled by a horizontal ceiling and two vertical walls, he primitive Navier-Stokes equations and the energy equation were solved numerically in time dependent form by a marker and cell method. A successive over-relaxation method for the elliptic portion of the problem and an explicit method for the parabolic portion were applied for the range of Grashoff number of $5{\times}10^3\;to\;5{\times}10^4$ to get the transient and steady state dimensionless temperature and velocity profiles. For the range of aspect ratio $L/H{\leqq}2.4$ in which only a pair of convection rolls exists mean Nusselt number calculated are as follows : $$N_{NU}0.89\;N_{Gr}^{0.2}(H/L)^{0.45}$$ By path lines drawn by marker particle trajectories roll number of cellular motion were observed for various aspect ratio of the enclosure.

• Journal of Ship and Ocean Technology
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• v.12 no.1
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• pp.16-27
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• 2008

The interaction between advancing ships and the waves generated by them plays important roles in wave resistances and ship motions. Wave breaking phenomena near the ship bow at different speeds are investigated both numerically and experimentally. Numerical simulations of free surface profiles near the fore bodies of ships are performed and visualized to grasp the general trend or the mechanism of wave breaking phenomena from moderate waves rather than concentrating on local chaotic irregularities as ship speeds increase. Navier-Stokes equations are differentiated based on the finite difference method. The Marker and Cell (MAC) Method and Marker-Density Method are employed, and they are compared for the description of free surface conditions associated with the governing equations. Extra effort has been directed toward the realization of extremely complex free surface conditions at wave breaking. For this purpose, the air-water interface is treated with marker density, which is used for two layer flows of fluids with different properties. Adaptation schemes and refinement of the numerical grid system are also used at local complex flows to improve the accuracy of the solutions. In addition to numerical simulations, various model tests are performed in a ship model towing tank. The results are compared with numerical calculations for verification and for realizing better, more efficient research performance. It is expected that the present research results regarding wave breaking and the geometry of the fore body of ship will facilitate better hull form design productivity at the preliminary ship design stage, especially in the case of small and fast ship design. Also, the obtained knowledge on the impact due to the interaction of breaking waves and an advancing hull surface is expected to be applicable to investigation of the ship bow slamming problem as a specific application.

• Journal of the Society of Naval Architects of Korea
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• v.29 no.3
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• pp.117-124
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• 1992

Waves around a practical hull form and a series 60 model are computed by rectangular variable spacing and staggered flesh systems based on MAC(Marker and Cell) method. As a governing equation, the Euler equation is adopted. The comparison indicates that the computed waves are in good agreement with the measured results and that the MAC method is useful. On the other hand, a critical condition for the appearance of sub-breaking waves derived from the in viscid instability analysis is applied to the calculated flow field around a blunt bow. It is confirmed that the derived condition detects well the appearance of sub-breaking waves.

• Journal of the Korea Society of Computer and Information
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• v.17 no.10
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• pp.35-41
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• 2012

We propose a new marker driven Watershed algorithm for automated segmentation of clustered cell from microscopy image with less over segmentation. The Watershed Transform is able to segment extremely complex objects which are highly touched and overlapped each other. The success of the Watershed Transform depends essentially on the finding markers for each of the objects of interest. For extracting of markers positioning around center of each cell we used radial symmetry and iterative voting algorithms. With synthetic and real images, we quantitatively demonstrate the performance of our method and achieved better results than the other compared methods.

• Development and Reproduction
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• v.16 no.4
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• pp.353-361
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• 2012

Human embryonic stem (ES) cells are a potential source of cells for developmental studies and for a variety of applications in transplantation therapies and drug discovery. However, human ES cells are difficult to culture and maintain at a large scale, which is one of the most serious obstacles in human ES cell research. Culture of human ES cells on MEF cells after disassociation with accutase has previously been demonstrated by other research groups. Here, we confirmed that human ES cells (H9) can maintain stem cell properties when the cells are passaged as single cells under a feeder-free culture condition. Accutase-dissociated human ES cells showed normal karyotype, stem cell marker expression, and morphology. We prepared frozen stocks during the culture period, thawed two of the human ES cell stocks, and analyzed the cells after culture with the same method. Although the cells revealed normal expression of stem cell marker genes, they had abnormal karyotypes. Therefore, we suggest that accutase-dissociated single cells can be usefully expanded in a feeder-free condition but chromosomal modification should be considered in the culture after freeze-thawing.

• Korean Journal of Agricultural Science
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• v.45 no.2
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• pp.238-247
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• 2018

The overall consumption of meat is increasing as the level of national income increases. The end weight is a trait closely associated with dressed meat. Genome-wide association study (GWAS) is an effective method of analyzing genetic variation and gene identification associated with a number of natural alternative traits because it can detect variations. So this paper did a GWAS analysis to identity the location on the genome related to the end weight in purebred landrace pigs and to explore the relevant candidate gene. This study identified a significant single nucleotide poly morphism (SNP) marker in chromosome 6 (ASGA0029422, $p=1.22{\times}10^{-6}$). Adhesion G protein-coupled receptor L2 (ADGRL2) was found to be the candidate gene at the identified SNP marker location. ADGRL2 genes have been found to be associated with cell development in relation to the external and internal environment of a cell. In addition, genotype and statistical analyses were done on nine variations on the exon of ADGRL2. The results show that the SNP marker (ASGA0029422, $p=1.32{\times}10^{-6}$) was significant, but the significance of the nine variations on the ADGRL2 exon was not verified. However, by performing further experiments and functional studies on other SNPs showing possible genetic ADGRL-Exon mutations, objects with high associations of high-end weights can be selected.

• Journal of Pathology and Translational Medicine
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• v.52 no.6
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• pp.404-410
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• 2018

Background: Fine-needle aspiration cytology serves as a safe, economical tool in evaluating thyroid nodules. However, about 30% of the samples are categorized as indeterminate. Hence, many immunocytochemistry markers have been studied, but there has not been a single outstanding marker. We studied the efficacy of CD56 with human bone marrow endothelial cell marker-1 (HBME-1) in diagnosis in the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) category III. Methods: We reviewed ThinPrep liquid-based cytology (LBC) samples with Papanicolaou stain from July 1 to December 31, 2016 (2,195 cases) and selected TBSRTC category III cases (n=363). Twenty-six cases were histologically confirmed as benign (six cases, 23%) or malignant (20 cases, 77%); we stained 26 LBC slides with HBME-1 and CD56 through the cell transfer method. For evaluation of reactivity of immunocytochemistry, we chose atypical follicular cell clusters. Results: CD56 was not reactive in 18 of 20 cases (90%) of malignant nodules and showed cytoplasmic positivity in five of six cases (83%) of benign nodules. CD56 showed high sensitivity (90.0%) and relatively low specificity (83.3%) in detecting malignancy (p=.004). HBME-1 was reactive in 17 of 20 cases (85%) of malignant nodules and was not reactive in five of six cases (83%) of benign nodules. HBME-1 showed slightly lower sensitivity (85.0%) than CD56. The specificity in detecting malignancy by HBME-1 was similar to that of CD56 (83.3%, p=.008). CD56 and HBME-1 tests combined showed lower sensitivity (75.0% vs 90%) and higher specificity (93.8% vs 83.3%) in detecting malignancy compared to using CD56 alone. Conclusions: Using CD56 alone showed relatively low specificity despite high sensitivity for detecting malignancy. Combining CD56 with HBME-1 could increase the specificity. Thus, we suggest that CD56 could be a useful preoperative marker for differential diagnosis of TBSRTC category III samples.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.17
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• pp.7497-7500
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• 2015

Background: Tumor markers, designated as a broad group of substances produced by malignancies, could be in the form of biochemical substances, immunological substances, cell surface changes and genetic alterations. Cancer, a disorder of cellular behavior is characterized by alteration of serum glycoproteins. L-fucose, a hexose, which is the terminal sugar in most of the plasma glycoproteins, may be useful as a tumor marker for the detection, monitoring and prognostic assessment of malignancies. The aim of the study was to ascertain the role of serum fucose as a biomarker for early detection of oral cancer and to compare serum fucose levels in healthy controls, leukoplakia and oral cancer patients. Materials and Methods: The study included 60 (100.0%) subjects, who were grouped as 20 (33.3%) control subjects, 20 (33.3%) squamous cell carcinoma patients and 20 (33.3%) leukoplakia patients. Fucose estimation was done using UV-visible spectrophotometry based on the method as adopted by Winzler using cysteine reagent. The results were analyzed statistically using ANOVA with Bonferroni post hoc tests. Results: Results showed a high significance in serum fucose in oral squamous cell carcinoma (OSCC) and leukoplakia subjects compared to normal controls. There was a gradual increase in the values noted from control to leukoplakia and to squamous cell carcinoma. Conclusions: Estimation of serum fucose may be a reliable marker and can be used as an effective diagnostic biomarker in oral squamous cell carcinoma patients.