• Bulletin of the Korean Chemical Society
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• v.17 no.8
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• pp.686-688
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• 1996

We have produced nanophase iron clusters inside a gas cell by decomposing iron pentacarbonyls from the mixture of ~20 Torr Fe(CO)5/~3 Torr SF6 with a pulsed CO2 laser. The product displayed a black tint. Its composition was identified to be mostly iron from an inductively coupled plasma (ICP) atomic emission spectrum. The X-ray diffraction (XRD) pattern indicates a body-centered cubic structure for the cluster. A transmission electron micrograph proves that their diameter ranges between 50 and 70 Å and their average diameter is 60 Å.

• The Korean Journal of Cytopathology
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• v.12 no.2
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• pp.121-125
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• 2001

Primary small cell carcinoma of the urinary bladder is a rare malignant tumor. A more rapidly fatal course may be seen in advanced stages of small cell carcinoma as compared to similar stages of urothelial carcinoma. It is very important to recognize this distinct form of bladder cancer by urinary cytology The differential diagnosis of small cell carcinoma of the urinary bladder includes metastatic small cell carcinoma, urothelial carcinoma, and primary or secondary malignant lymphoma. This article highlights the urinary cytologic diagnosis of a case of primary small cell carcinoma. A 59-year-old male presented with gross hematuria for five months. Urinary cytology showed high cellularity consisting of tiny monotonous tumor cells in the necrotic background. The tumor cells occurred predominantly singly, but a few in clusters. The cytoplasm was so scanty that only a very narrow rim of it was seen. The nuclei were oval or round and had finely stippled chromatin. Rarely, the nuclei contain visible nucleoli. Frequently cell molding was noted in clusters. Many single cells demonstrated nuclear pyknosis or karyorrhexis. The histologic findings of transurethral resection and partial cystectomy specimen were those of small cell carcinoma. Cytologic distinction may be very difficult but careful attention to clinical features and cellualr details can classify these neoplasms correctly.

• Microbiology and Biotechnology Letters
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• v.47 no.1
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• pp.164-171
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• 2019

Radiation therapy has many side effects, such as digestive mucosal ulcers, without regard to its efficacy. The purpose of this study is to address an alternative method to replace the limitation of radiation therapy using radiomimetic microbial ribotoxins. In the evaluation of cancer therapy, we analyzed the formation of colorectal cancer (CRC) cell spheroids, which can take into account the heterogeneous cellular constitution, tumor stem cells, and the surrounding microenvironment. Ribotoxic stress interfered with the spheroid structure composed of relatively small clusters. Spheroids under ribotoxic stress were structurally sparse and their shrinkage was very slow. In the control group, the clusters of strongly aggregated cells were resistant to physical stress, but the ribotoxic stress-exposed spheroids were easily broken up by the physical stress. Moreover, the ribosome-insulted CRC cells slowly migrated to form clusters and the cell-cell junctional points in the ribosome-insulted spheroids were rarer than those in the control CRC spheroid. Moreover, levels of the cell-to-cell junctional protein E-cadherin were suppressed by ribotoxic stress in both allograft and xenograft spheroids. In conclusion, the radiomimetic microbial ribotoxins induced structural defects in CRC cell spheroids via retardation of migration and cell-cell junction in the formation of three-dimensional structures, and provides a basis for the mechanism of pharmacological radiomimetic anticancer actions as an alternate to radiotherapy against cancer.

• The Korean Journal of Cytopathology
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• v.13 no.2
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• pp.70-73
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• 2002

Utilization of fine needle aspiration cytology (FNAC) in the diagnosis of odontogenic tumors seems to have little attention. Ameloblastoma is the most common epithelial odontogenic tumor. However, the cytologic findings of ameloblastoma are described recently. We report a case of ameloblastoma diagnosed by FNAC. The aspirated blood-tinged mucoid fluid from maxillary mass showed a few clusters of tumor cells with distinct two-cell population: basaloid cells with palisading arrangement and squamous cells with more abundant and eosinophilic cytoplasm. Nuclear atypism, pleomorphism or mitosis were absent. A few keratinized bodies in the tumor cell clusters and the third component, stellate cells were also characteristic.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.357-362
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• 1996

A way of quantitatively describing the tissue architecture we have investigated when developing a computer program for malignancy grading of transitional cell bladder carcinoma. The minimum spanning trees, MST was created by connecting the center points of the nuclei in the tissue section image. These nuclei were found by thresholding the image at an automatically determined threshold followed by a connected component labeling and a watershed algorithm for separation of overlapping nuclei. Clusters were defined in the MST by thresholding the edge lengths. For these clusters geometric and densitometric features were measures. These features were compared by multivariate statistical methods to the subjective grading by the pathologists and the resulting correspondence was 85% on a material of 40 samples.

• Genomics & Informatics
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• v.18 no.3
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• pp.26.1-26.6
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• 2020

Single-cell RNA sequencing (scRNA-seq) has been widely applied to provide insights into the cell-by-cell expression difference in a given bulk sample. Accordingly, numerous analysis methods have been developed. As it involves simultaneous analyses of many cell and genes, efficiency of the methods is crucial. The conventional cell type annotation method is laborious and subjective. Here we propose a semi-automatic method that calculates a normalized score for each cell type based on user-supplied cell type-specific marker gene list. The method was applied to a publicly available scRNA-seq data of mouse cardiac non-myocyte cell pool. Annotating the 35 t-stochastic neighbor embedding clusters into 12 cell types was straightforward, and its accuracy was evaluated by constructing co-expression network for each cell type. Gene Ontology analysis was congruent with the annotated cell type and the corollary regulatory network analysis showed upstream transcription factors that have well supported literature evidences. The source code is available as an R script upon request.

• Journal of Plant Biotechnology
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• v.31 no.3
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• pp.219-223
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• 2004

Embryogenic calli were induced from petioles of Aralia elata on MS solid medium supplemented with 1.0 mg/L 2,4-D. When embryogenic calli were transferred to MS liquid medium supplemented with 1.0 mg/L 2,4-D, embryogenic cells and embryogenic cell clusters were developed after 2 weeks of culture. Embryogenic cells were filtered through a 250 ${\mu}{\textrm}{m}$ sieve and the passed cells were proliferated and maintained in MS liquid medium supplemented with 1.0 mg/L 2,4-D. Embryogenic cell clusters entrapped on the sieve were transferred to 1/2 MS liquid medium without plant growth regulators, globular-shaped embryos were developed from embryogenic cell clusters after 2 weeks of culture. Numerous early stage somatic embryos could be developed to heart-shaped, torpedo-shaped, cotyledonary embryos and plantlets in 5 L bioreactor. Above results suggest that effective somatic embryo proliferation can be achieved via bioreactor culture systems in Aralia elata.

• Journal of Digital Convergence
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• v.20 no.2
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• pp.217-223
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• 2022

Subspace clustering for online data streams requires a large amount of memory resources as all subsets of data dimensions must be examined. In order to track the continuous change of clusters for a data stream in a finite memory space, in this paper, we propose a grid-based subspace clustering algorithm that effectively uses memory resources. Given an n-dimensional data stream, the distribution information of data items in data space is monitored by a grid-cell list. When the frequency of data items in the grid-cell list of the first level is high and it becomes a unit grid-cell, the grid-cell list of the next level is created as a child node in order to find clusters of all possible subspaces from the grid-cell. In this way, a maximum n-level grid-cell subspace tree is constructed, and a k-dimensional subspace cluster can be found at the k^th level of the subspace grid-cell tree. Through experiments, it was confirmed that the proposed method uses computing resources more efficiently by expanding only the dense space while maintaining the same accuracy as the existing method.

• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.561-566
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• 2005

Polycrystalline silicon films were deposited using hot wire CVD (HWCVD). The deposition of silicon thin films was approached by the theory of charged clusters (TCC). The TCC states that thin films grow by self-assembly of charged clusters or nanoparticles that have nucleated in the gas phase during the normal thin film process. Negatively charged clusters of a few nanometer in size were captured on a transmission electron microscopy (TEM) grid and observed by TEM. The negatively charged clusters are believed to have been generated by ion-induced nucleation on negative ions, which are produced by negative surface ionization on a tungsten hot wire. The electric current on the substrate carried by the negatively charged clusters during deposition was measured to be approximately $-2{\mu}A/cm^2$. Silicon thin films were deposited at different $SiH_4$ and $H_2$ gas mixtures and filament temperatures. The crystalline volume fraction, grain size and the growth rate of the films were measured by Raman spectroscopy, X-ray diffraction and scanning electron microscopy. The deposit ion behavior of the si1icon thin films was related to properties of the charged clusters, which were in turn controlled by the process conditions. In order to verify the effect of the charged clusters on the growth behavior, three different electric biases of -200 V, 0 V and +25 V were applied to the substrate during the process, The deposition rate at an applied bias of +25 V was greater than that at 0 V and -200 V, which means that the si1icon film deposition was the result of the deposit ion of charged clusters generated in the gas phase. The working pressures had a large effect on the growth rate dependency on the bias appled to the substrate, which indicates that pressure affects the charging ratio of neutral to negatively charged clusters. These results suggest that polycrystalline silicon thin films with high crystalline volume fraction and large grain size can be produced by control1ing the behavior of the charged clusters generated in the gas phase of a normal HWCVD reactor.

• The Korean Journal of Cytopathology
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• v.8 no.1
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• pp.69-75
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• 1997

Well differentiated fetal adenocarcinoma of the lung Is a subtype of pulmonary blastoma. In this report, CT-guided fine needle aspiration smears were performed at the right upper lobe of the lung in a 45 year-old male patient who had the smoking history of one pack per day for 25 years. The smears disclosed round, papillary, and tubular patterns of cell clusters. The individual cells had relatively uniform, small to medium sized nuclei without nucleoli, and showed vesicular or eosinophilic cytoplasm with Indistinct cell border. The morules were seen in the central area of papillary clusters. They were composed of two cell types, outer single layered cuboidal cellular lining and central three-dimensional cluster of cells simulating fetal lung. These cytologic features need to be differentiated from usual pulmonary adenocarcinoma, carcinoid, and pulmonary blastoma. On histologic findings, the tumor arised in the bronchial epithelium. And the tumor cells had abundant intracytoplasmic glycogen with neuroendocrine feature on histochemical study. In addition, the multiplicity of this tumor is the unique point comparable to the previous reports.