• Applied Microscopy
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• 제41권4호
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• pp.229-234
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• 2011

식물세포 핵 내에 형성되는 여러 형태의 함유구조 특성 및 발달양상을 다양한 식물에서 조사하여 비교 논의하였다. 이들은 원시적인 양치식물에서부터 고도로 분화한 현화식물에 이르기까지 많은 식물군에서 발달하나, 종간에는 계통적학인 유연관계 없이 각각 독립적으로 나타난다. 핵 내 함유구조는 내부 미세구조 특징에 따라 부정형(amorphous), 결정형(crystalline), 섬유상(fibrillar), 판상 (lamellar), 미세관상 (tubular)의 5~6 유형으로 구분된다. 가장 흔한 유형은 결정형으로 수 마이크론에 이르는 비교적 커다란 구조를 이루며, 내부구조 간 격자거리는 약 10 nm로 배열되어 있다. 핵 함유구조들은 막으로 둘러싸이지 않고 막과는 무관하게 발달하며, 핵 기질 내 인과의 구조적, 기능적 연계성이 강하게 추정되고 있다. 핵 결정체 및 미세구조 형성에 대한 연구는 이들의 구조와 기능에 대하여 새로운 정보를 제공하나, 핵 결정체에 대한 3차원적 입체구조 분석과 이들 구조를 핵에서 분리시켜 연구할 분자생물학적, 생화학적인 실험법들이 요구되고 있다. 특히, 핵 결정의 3-D 입체구조를 재구현할 수 있는 HVEM 고압전자현미경 및 tomography에 의한 연속절편 연구는 이들 구조에 대한 심도 있는 정보를 제공할 것이다. 본 논문에서는 다양한 식물세포 내 핵에 발달하는 함유구조에 대하여 연구된 구조 및 기능 등을 연계하여 그 중요성을 종합적으로 논의하였다.

• Nuclear Engineering and Technology
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• 제52권4호
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• pp.811-818
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• 2020

Y-containing CLAM steels were melted via vacuum induction melting and electroslag remelting. In this study, the evolution, microstructure, and mechanical properties of the alloy inclusions (ESR-1 (0 wt.% Y), ESR-2 (0.016 wt.% Y) and ESR-3 (0.042 wt.% Y)) were investigated. Further, the number of inclusions in ESRed steel was observed to obviously decrease, and the distributions were more uniform. The fine Y-Al-O inclusions (1-2 ㎛) were the main inclusions in ESR-2. The addition of Y affected the prior austenite grain size (PAGZ), increasing the tensile strength at test temperature. Low ductile-brittle transition temperature (DBTT) was obtained because of the fine PAGZ and dispersive inclusions. For the ESRed CLAM steel with 0.016 wt.% Y, the yield strengths were 621 MPa at 20 ℃ and 354 MPa at 600 ℃ in air. Further, the uniform elongation and elongation of the ESR-2 alloy were 5.5% and 20.1% at 20 ℃, respectively. Meanwhile, the DBTT tested using full-size Charpy impact specimen (55 cm × 10 cm × 10 cm) was reduced to -83 ℃.

• Nuclear Engineering and Technology
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• 제51권6호
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• pp.1589-1595
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• 2019

In this paper, the CLAM steel strengthened by micro-scale Y-Zr-O was prepared by vacuum induction melting followed by electroslag remelting (VIM-ESR). Yttrium (Y) and zirconium (Zr) were easy to aggregates into massive yttrium-zirconium-rich inclusions in the steel melted by vacuum induction melting (VIM), which would interrupt the continuity of the matrix and reduce the mechanical properties of steel. Micron-sized Y-Zr-O inclusions would be produced with the removal of original blocky Y-Zr-rich inclusions and the submicron-sized inclusions smaller than $0.2{\mu}m$ could be retained in the steel. The small grain size and the better refinement and distribution uniformity of Y-Zr-O inclusions after remelting would be responsible for the better yield strength and toughness. For VIM-ESR alloy, the ultimate tensile strength is 749 MPa and the yield strength is 642 MPa at room temperature, meanwhile they are 391 MPa and 367 MPa at $600^{\circ}C$, respectively. Meanwhile, the ductile-brittle transition temperature (DBTT) reduced from $-43^{\circ}C$ (VIM) to $-76^{\circ}C$ (VIM-ESR).

• Nuclear Engineering and Technology
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• 제54권7호
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• pp.2376-2385
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• 2022

Two groups of oxide dispersion-strengthened reduced-activation ferritic/martensitic steels (A and B) were prepared by adding Y, Ti, and Zr into steels through vacuum induction melting to investigate the inclusions, microstructures, mechanical properties of the alloys. Results showed that particles with Y, Ti, and Zr easily formed. Massive, Zr-rich inclusions were found in B steel. Density of micron inclusions in A steel was 1.42 × 10¹⁴ m^-3, and density of nanoparticles was 3.61 × 10¹⁶ m^-3. More and finer MX carbides were found in steel tempered at 650 ℃, and yield strengths (YS) of A and B steel were 714±2 and 664±3.5 MPa. Thermomechanical processing (TMP) retained many dislocations, which improved the mechanical properties. YSs of A and B treated by TMP were 725±3 and 683±4 MPa. The existence of massive Zr-rich inclusions in B steels interrupted the continuity of the matrix and produced microcracks (fracture), which caused a reduction in mechanical properties. The presence of fine prior austenite grain size and inclusions was attributed to the low DBTTs of the A steels; DBTTs of A650 and A700 alloy were -79 and -65 ℃. Tempering temperature reduction and TMP are simple, readily useable methods that can lead to a superior balance of strength and impact toughness in industry applications.

• 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.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2003년도 추계학술발표대회 요약집
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• pp.341.2-341.2
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• 2003

• 대한세포병리학회지
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• 제17권2호
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• pp.148-152
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• 2006

Due to its nuclear pleomorphism, knowledge regarding the cytological findings of cerebellar hemangioblastoma can lead to misdiagnosis when using squash specimens, which in other circumstances serves as a useful adjunct in the diagnosis of brain tumors on frozen section. We recently experienced the cytological findings of a cellular variant of cerebellar hemangioblastoma in a 51-year-old man. Squash specimens revealed scattered single tumor cells, with pleomorphic nuclei and cytoplasmic vacuoles, on a hemorrhagic background. The cellular clusters were composed of spindle-shaped endothelial cellsin addition to densely clustered stromal cells. Intranuclear inclusions were frequently seen. The nuclear pleomorphism, bubbly cytoplasmic vacuoles and presence of intranuclear inclusions, seen in the squash specimen, may increase the difficulty of frozen section diagnosis of cerebellar hemangioblastoma. Awareness of the cytologicalfindings of hemangioblastoma is needed to avoid the pitfalls in the intraoperative diagnosis of cerebellar hemangioblastomas.

• 한국재료학회지
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• 제9권2호
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• pp.217-225
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• 1999

The effect on the pitting corrosion resistance of laser welding and surface treatment developed as a repair method of stream generator tubing material that was a major component of primary system at nuclear power plant was observed. Some heat-treated Alloy 600 tubing materials used at domestic nuclear power plants were laser-surface observed. Some heat-treated Alloy 600 tubing materials used at domestic nuclear power plants were laser-surface melted and the microstructural characteristics were examined. The pitting corrosion resistance was examined through Ep(pitting potential) and degree of pit generation by means of the electrochemical tests and the immersion tests respectively. The pit formation characteristics were investigated through microstructural changes and the pit initiation site and pit morphology. The test results showed that the pitting corrosion resistances was increased in the order of the followings; sensitized Alloy 600, solution annealed alloy600, and laser surface melted Alloy 600. Pits were initiated preferably at Ti-containing inclusions and their surroundings in all tested specimens and it is believed that higher pitting resistance of laser-surface treated Alloy 600 was caused by fine, homogeneous distribution of non-soluble inclusions, the disappearance of grain boundary, and the formation of dense, stable oxide film. The major element of corrosion products filled in the pit was Cr. On the other hand, Fe was enriched in the deposit formed on the pit.

• 대한수의학회지
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• 제15권1호
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• pp.57-67
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• 1975

The poxvirus group is considered to be a typical cytoplasmic inclusion forming virus. Every poxvirus has been reported to produce only one kind of inclusion in the infected tissues. A vague concept that inclusions of poxviruses are eosinophilic or acidophilic has prevailed. Although many papers and theories about the nature of the inclusion have been presented, most of them are not quite convincing on the point of the relations with virus multiplication, and an analysis of papers published showed that there seem to be many discrepancies in the descriptions of the nature of the poxvirus inclusions. Comparative studies on host-virus interaction with cowpox, orf, swinepox and fowlpox viruses which selected from each Group (I-IV) of poxviruses were performed from the morphological and virological standpoints. At first, in cowpox virus-FL cell system, as a comparative model, cytoplasmic inclusion, nucleic acid metabolism by autoradiography and detection of viral antigen by immunofluorescence were studied and obtained the results as follows: 1. The focus-like cytopathic effect (CPE) at early stage developed to entire culture at terminal stage of infection, and also the developing status of CPE was correlated to viral doses for inoculation. Two kinds of cytoplasmic inclusions which named A and B type were easily observed by Giemsa, hematoxylin-eosin (H & E) and May-Greenwald Giemsa (MGG) stainings in the infected cells. The B type inclusions were formed at early stage of infection and the A type inclusions were produced subsequently the B type formation. The B type which common type inclusion in poxviruses was a small compact or aggregate at early stage and developed to a large diffuse body at terminal stage of infection. On the other hand, the A type inclusion which depend upon the kind of virus was appeared as round and discrete shape, and its size and number was increased gradually during the culture period. It was characteristic to form distinct halos around the both types of inclusions in acid fixed, H & E stained preparations of infected cultures. The B type inclusion was always positive in Feulgen reaction and showed as DNA containing body but the A type inclusion was not. 2. In the relationship between inclusion and DNA metabolism of infected cells by the qualitative autoradiography using 3H-thymidine, the appearance of silver grains was coincided with B type inclusion but not with A type inclusion. This showed that the DNA synthesis was proceeded in all B type inclusions except those in the terminal stage with a diffuse form. This suggested that the B type inclusions are only sites of DNA synthesis and this was proceeded after the cell infection independently. The activity of DNA synthesis of the inclusions was nearly the same as that of the nucleic of normal cells and non-inclusion bearing cells. and non-inclusion bearing cells. Regardless of the size of the degree of DNA synthesis of the B type inclusion, inclusion bearing cells all showed remarkable suppression of nuclear DNA synthesis. 3. By the direct fluorescent antibody technique viral antigen in infected cells was detected. The B type inclusions have been proved to contain a great deal of viral antigen, whereas the basic substance of A type inclusion did not show antigenicity except the round edge. It was suggested that the round edge fluorescence might be caused by the glare of cytoplasmic viral antigen which pushed out and concentrated by the A type inclusion development. 4. Hemorrhagic red pock formations on chorioallantoic membrane of embryonated chicken egg had proved the characteristic of used viral strain. 5. By the above studies on the nature of two types of inclusions and the role they play in virus multiplication, it was concluded that the B type inclusion must be the site of the synthesis of viral DNA and protein as well as the site of the virus.

• Applied Microscopy
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• 제9권1호
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• pp.35-56
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• 1979

To investigate ultrastructural characteristics of cancer cells of the nervous system, 25 cases; i.e. astrocytoma(9), oligodendroglioma(1), medulloblastoma(1), meningioma(5), pinealoma(2) and pituitary adenomas(7). The common findings were marked irregularity of nuclear membrane with pronounced infoldings, clumping of heterochromatin along inner nuclear membrane, enlargement of nucleolus, and frequent observations of nuclear bodies and nuclear inclusions. But these findings are also the signs 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. Among cytoplasmic organelles, massive fibrils are characteristic of astrocytoma and meningiomas, cytoplasmic protofibrils such as glial process and microvesicles in oligodendroglioma, secretory granules are characteristic in pituitary adenomas, and fine filamentous fibrils and desmosomes are characteristic of fibroblastic type of meningioma. Intercellular relationships and cell membrane specialization are important features in the differential diagnosis of various undifferentiated tumors. The frequent resolution of difficult diagnosis problems by electron microscopy outweighs the disadvantages of this technique, such as the expense and time required.