• Transactions on Electrical and Electronic Materials
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• 제13권4호
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• pp.212-214
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• 2012

Both the electrically positive and negative particles in a cell of quick response-liquid powder display (QR-LPD) are surrounded by conductive electrodes on the upper and lower substrate and the dielectric materials of the barrier ribs. Particles in a cell are attached to or detached from the other materials by image force, electric field, Coulomb's force, and Van der Waals' force. Through these forces, the moving particles form an image but induce clumping phenomena. Particles having a large kinetic energy by a large q/m value crash into the opposite electrode with high speed at a large driving voltage and quickly lose electrically charged material. As a result, these particles are clumped and degrade panel performance. The clumped particles in a cell are observed by microscopic photographs and ascertained by a response time. When the bias voltage is increased to 0.68-0.76 $V/{\mu}m$, particle clumping occurs abruptly and the response time increases sharply. This particle clumping is similarly observed after the number of driving times at the driving voltage (0.42-0.64 $V/{\mu}m$).

• Journal of Microbiology and Biotechnology
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• 제29권10호
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• pp.1603-1606
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• 2019

Sortase A (SrtA), a type of transpeptidase responsible for anchoring surface proteins to the peptidoglycan cell wall, is important in the virulence of gram-positive bacteria. Three compounds were isolated from marine-derived Streptomyces sp. MBTH32 using various chromatography techniques. The structures of these compounds were determined based on spectroscopic data and comparisons with previously reported data. Among the metabolites tested, lumichrome showed strong inhibitory activity against Staphylococcus aureus SrtA without affecting cell viability. The results of cell clumping activity assessment suggest the potential for using this compound to treat S. aureus infection by inhibiting SrtA activity.

• KSBB Journal
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• 제28권1호
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• pp.54-59
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• 2013

Three isolates, E. faecium P1, P2 and P3, from intestinal drugs of three phamaceutical companies, four clinical vancomycin resistant isolates, E. faecium V1, V2, V3 and E. faecalis V4, and three isolates, E. faecalis DW01, DW07 and DW14, from infant feces were tested for the presence of virulence genes, ace, agg, esp, efaA, gelE, sprE, vanA and vanB as well as fsrABC, regulatory genes of gelE and sprE, cylMBA, cytolysin activation genes and cpd, cob and ccf, pheromone genes by PCR and for their phenotype activities such as protease, biofilm formation, cell clumping and hemolysis. The genes encoding cell surface adherence proteins, ace, agg, esp and efaA, were predominantly amplified from the vancomycin resistant strain V4 and the fecal isolates DW01, DW07 and DW14. Both protease and biofilm formation activity were detected only from E. faecalis V4 from which the PCR products of gelE and spreE as well as fsrABC were amplified. The pheromone genes were amplified from the V4, DW01, DW07 and DW14 strains and these strains showed clumping activity. Biofilm formation was observed from the strains DW01, DW07 and DW14, all of which produced PCR products of pheromone, and V4 as well. Whole cytolysin regulator genes were amplified from DW01, DW07 and DW14 and ${\beta}$-hemolysis activity was detected from these strains. Any virulence genes or activities except the pheomone gene ccf were not detected from the pharmaceutical isolates, E. faecium P1, P2 and P3.

• Applied Microscopy
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• 제5권1호
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• pp.21-30
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• 1975

To investigate ultrastructural characteristics of cancer cell nucleus, 29 cases of malignant tumors of 9 different types were examined. The common findings were marked irregularity of nuclear membrane with pronounced infoldings, clumping of heterochromatin along inner nuclear membrane, enlargement and disturbance of configuration and composition of nucleolus, and frequent observations of nuclear bodies and nuclear inclusions. These findings confirm what have been observed by light microscopy, and are also the signes that can be observed in hyperactive cells. Thus, ultrastructural characteristics of cancerous nucleus are the great variability of nuclear size, shape and composition, but none of them appear to be specific.

• 치과방사선
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• 제25권2호
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• pp.343-362
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• 1995

The purpose of this study was to investigate chronic radiation effects on the basal cell of the rat tongue epithelium according to different irradiation timing. Forty-two female rats were devided into 5 experimental groups according to different irradiation timing and were irradiated single dose of 396cGy by MK cell irradiator using Cs-137. Experimental rats were sacrificed at the 2nd week, 4th week and 6th week after birth. The specimens were examined with light microscope and transmission electron microscope. The following results were obtained. 1. The first changes after irraditation were vacuoles. The vacuoles were chiefly observed in the cytoplasm, perinuclei area, and nuclei. 2. The most severe degenerative changes in the basal cell layer were observed in all experimental groups. ; cellular disarrangement, vacuole formation, widening of intercellular space, enlarged mitochondria & rER, and chromatin clumping were seen. 3. The cellular degenerative changes were most severe at the 4th week after birth in all experimental group, and the basal cell hyperplasia was seen at the 6th week in the most of experimental groups 4. The experimental groups 3 and 4 show more severe and more prolonged cellular degeneration than experimental groups 1 and 2, which were irradiated in pregnancy, and experimental group 5, which was irradiated after tongue maturation.

• 대한세포병리학회지
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• 제4권2호
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• pp.150-155
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• 1993

We report a case of placental site trophoblastic tumor with cytologic features of cervico-vaginal smear. The smear revealed several loose clusters of atypicai cells in slightly hemorrhagic and inflammatory background. Tumor cells were large in size and polyhedral to round with abundant cytoplasm Nuclei revealed consider-able variation in size, shape, and degree of chromatin clumping. Cytologically, it was difficult to differentiate from squamous cell carcinoma of uterine cervix. Curettage and hysterectomy specimen revealed typical histologic features of placental site trophoblastic tumor composed of intermediate type trophoblasts.

• 한국정보처리학회논문지
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• 제3권3호
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• pp.512-522
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• 1996

산발적인 지역의 가입자들에 대한 광대역 ISDN(B-ISDN) 서비스를 위하여 위성 회선을 적용하는 것이 검토 되고 있다. 위성 회선의 효율적인 ATM 셀 전송으로 TDMA 방식을 적용하는 것이 유효하지만, TDMA와 ATM의 동기/비동기성의 차이로 인한 셀 지연 변이를 보상하는 방법이 필요하게 된다. 본 논문에서는 지금까지 제안되어 왔던 셀 지연 변이의 보상 방식 중에서 많은 이점을 갖는 셀 계수 방식의 지연 특성을 응용 함으로써 트래픽이 포아송 입력, 마르코프 변조 포아송 과정 입력인 경우에 대하여 셀 제어 시간(Tc)의 적화를 유도하였다. 그리고 셀 클럼핑 현상을 억제하기 위하여 이산 타임 스탬프 방식을 제안 하여 ATM 전송에 따른 CDV 분포의요구 품질의 범위를 해석 하고 검증하였다. 본 방식의 적용에 따라 CDV 분포폭은 약1.2$\times$Tc 정도로 억제가 가능 하여이산 타임 스탬스방식에 따른 전체적인 셀 지연 변이가 감소됨을 알 수 있었다.

• Applied Microscopy
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• 제20권1호
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• pp.65-76
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• 1990

The effect of calcium-free reperfusion for 5, 10, and 15 minutes, respectively, followed by continuous reperfusion with normal Tyrode solution containing 1.0mM calcium chloride, after global ischemia in the isolated perfused guinea pig heart by Langendorff techniques was examined with transmission electron microscope. Compared to the nomal Tyrode solution-perfused control hearts, the 5 minute calcium-free-reperfused hearts showed loss or thickening of Z lines, focal sarcolemmal disruption, mitochondrial swelling, clumping of chroma-tin, intracellular fluid accumulation, and some separation of cell junctions, especially the fasciae adherentes. These changes became more severe in the hearts of 10 minute calcium-free reperfusion. Subsarcolemmal larger bleb and near complete separation of cell junctions were noticed. In the 15 minute calcium-free-reperfused hearts, irreversible ultrastructural changes including contraction bands, biazrre mitochondria, and sarcolemmal destruction were widely distributed. The severity of myocardial changes were in accordance with the duration of calcium-free reperfusion. These changes indicate that calcium-free reperfusion regardless of its duration could not salvage the post-ischemic myocardium probably due to development of calcium paradox.

• 대한세포병리학회지
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• 제1권2호
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• pp.158-163
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• 1990

Ancient (degenerated) schwannomas are benign tumors that display pronounced degenerative changes including cyst formation, calcification, hemorrhage, and hyalinization. The tumors are usually infiltrated by large numbers of inflammatory cells such as neutrophils, lymphocytes, siderophages, and histiocytes. They are located in deep locations such as the retroperitoneum and must be differentiated from malignant soft tissue tumors because spindle cells with nuclear atypia may be present. In the fine needle aspiration biopsy. The cytologic findings of two cases of ancient schwannoma occurring in posterior mediastinum and retroperitoneum, respectively, are described. Computerized tomographic findings of both cases showed changes of cystic degeneration or necrosis. A case occurred in retroperitoneum revealed features of destruction of vertebral body to suggest a malignant soft tussue tumor radiologically. The cytologic findings of aspiration biopsy of both tumors revealed that the tumor cells were spindle in shape with elongated nuclei. Some of tumor cells were arranged in a palisading fashion. Cell structures that resemble the Verocay bodies were observed. Some of the tumor cells showed pleomorphic bizarre nuclei, but no mitotic activity or chromatin clumping was seen. Inflammatory cells, siderophages and histiocytes were scattered in fibrillar material. These cytologic findings are important in the diagnosis of ancient schwannoma and in the differentiation of this tumor from the malignant spindle cell tumor.

• 대한세포병리학회지
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• 제10권2호
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• pp.157-162
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• 1999

Primary non-Hodgkin's lymphoma of the lung is rare among extranodal lymphomas. The most common form is low grade B-cell type originated from the mucosa-associated lymphoid tissue (MALT) of the lung and primary peripheral T cell lymphoma of the lung is extremely rare. We recently experienced a case of fine needle aspiration cytology of primary peripheral T cell lymphoma of the lung in a 39-year-old male patient. The cytologic smears revealed some sheets of reactive epithelial cells, epithelioid histiocytes, and numerous polymorphous population of lymphoid cells composed of small and intermediate sized lymphoid cells and mature lymphocytes. Lymphoid cells were slightly larger than normal mature lymphocytes and showed significant irregularity of nuclear membrane. The internal nuclear structure was marked by chromatin clumping, clear parachromatin areas, and inconspicuous nucleoli. Histopathologically, atypical small lymphocytes infiltrated in the interstitium and alveolar sac. By the immunohistochemical study and molecular biologic study of gene rearrangement, the T cell clonality of atypical lymphoid cells was confirmed.