• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.491-495
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• 2004

The industries use polymer materials for many purposes for they have many merits. The costs of these materials take up too great a proportion of the overall cost of products that use these materials as their major material. It is advantage for polymer industries to reduce these costs. The microcellular foaming process was developed in the early 1980s to solve this problem and proved to be quite successful. Microcellular foaming process uses inert gases such as $CO_2$, $N_2$. As these gases solve into polymer matrices, many properties are changed. The microcellular foaming process makes the glass transition temperature of polymers to low, and diminish the residual stress of polymer matrices. Besides, the microcellular foaming process has several merits, impact strength elevation, thermal insulation, noise insulation, and raw material saving etc. This characteristic of microcellular foaming process has influenced by cell morphology. The cell morphology means cell size and cell density. The cell morphology has influenced by many factors. The examples of factor are pressure drop rate, foaming temperature, foaming time, saturation pressure, saturation time etc. Among their factors, pressure drop rate is the most important factor for cell morphology in microcellular foaming injection molding process. This paper describes about the cell morphology change in accordance with the pressure drop rate of microcellular foaming injection molding process.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 춘계학술대회 논문집
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• pp.57-58
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• 2008

• 대한의용생체공학회:의공학회지
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• 제42권5호
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• pp.232-240
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• 2021

Heterogeneity in cancer is the major obstacle for precision medicine and has become a critical issue in the field of a cancer diagnosis. Many attempts were made to disentangle the complexity by molecular classification. However, multi-dimensional information from dynamic responses of cancer poses fundamental limitations on biomolecular marker-based conventional approaches. Cell morphology, which reflects the physiological state of the cell, can be used to track the temporal behavior of cancer cells conveniently. Here, we first present a hybrid learning-based platform that extracts cell morphology in a time-dependent manner using a deep convolutional neural network to incorporate multivariate data. Feature selection from more than 200 morphological features is conducted, which filters out less significant variables to enhance interpretation. Our platform then performs unsupervised clustering to unveil dynamic behavior patterns hidden from a high-dimensional dataset. As a result, we visualize morphology state-space by two-dimensional embedding as well as representative morphology clusters and trajectories. This cell morphology profiling strategy by hybrid learning enables simplification of the heterogeneous population of cancer.

• 통합자연과학논문집
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• 제16권2호
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• pp.69-74
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• 2023

In Dictyostelium , there are 15 Ras subfamilies, including 11 Ras, 3 Rap, 1 Rheb. The Ras proteins are involved in regulating various cell processes as switch proteins. The functions of many Ras proteins have been identified, but some of Ras proteins have not yet been identified. Here, we focused on identifying the roles of RasW among them. To investigate the functions of RasW in cell morphology, cell migration, and development in Dictyostelium , we compared the phenotypes of wild-type cells and rasW null cells. rasW null cells showed a larger, more spread-out morphology and reduced cell motility compared to wild-type cells. There was no significant difference between wild-type cells and rasW null cells during multicellular developmental process. These results suggest that RasW is involved in regulating cell morphology and cell migration in Dictyostelium.

• Journal of Radiation Protection and Research
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• 제34권1호
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• pp.15-24
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• 2009

The effect of low doses of ultraviolet (UV) irradiation on morphology changes of cell has been studied based on the observation of the cell length. It was shown that UV-irradiated cell has different behavior in comparison with non-irradiated cell. From the histogram of cell-length distribution, it was confirmed that cell cycle of non irradiated cell was 28 hours, and that cell cycle of irradiated cell with dose of $20\;Jm^{-2}$ was delayed (39 hours), while irradiated cell with $40\;Jm^{-2}$ and $60\;Jm^{-2}$ did not divide and kept growing continuously. It was supposed that in case of $20\;Jm^{-2}$ of irradiation dose, the cell cycle was delayed because the checkpoint worked in order to repair DNA damage induced by generation of pyrimidine dimer, reactive oxygen species and so on. It was also supposed that in case of $40\;Jm^{-2}$ and $60\;Jm^{-2}$ of irradiation dose, overgrowth was induced because the checkpoint was not worked well. The morphology of overgrown cell was similar to that of normally senescent cell. Therefore, it was considered that cell senescence was accelerated by UV irradiation with irradiation doses of $40\;Jm^{-2}$ and $60\;Jm^{-2}$.

• 한국세라믹학회지
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• 제40권6호
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• pp.601-607
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• 2003

재료의 선택에 따른 생체친화성을 고찰하기 위해서 조골세포의 세포배양실험을 실시하였으며, 이로부터 세포의 부착형상, 증식, 분화의 정도를 살펴보았다. 본 실험에서 세포배양모재는 체내식립재료로 주목을 받고 있는 TiO$_2$, 3Y-TZP, HA (Hydroxyapatite) 그리고 Ti를 사용하였으며 대조군으로 Thermanox를 선택하였다. 일반적으로 모든 시편들은 같은 세포배양시간일때 거의 유사한 세포부착형상을 보였다. 그러나, HA위의 세포들은 나머지 시편들보다 좀 더 두꺼운 형상을 보였으며 빠른 세포의 부착 및 퍼짐으로 인한 overlapping이 자주 관찰되었다. 세포의 증식 및 분화의 경우에도 생체활성의 특성을 지니는 HA가 가장 높은 값을 보였으며 생체불활성재료인 경우에는 Ti, TiO$_2$, 3Y-TZP모두 유의한 차이를 보이지 않고 비슷한 경향을 나타내었다.

• Molecules and Cells
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• 제28권2호
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• pp.93-98
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• 2009

A plant-specific gene was cloned from melon fruit. This gene was named downward leaf curling (CmDLC) based on the phenotype of transgenic Arabidopsis plants overexpressing the gene. This expression level of this gene was especially upregulated during melon fruit enlargement. Overexpression of CmDLC in Arabidopsis resulted in dwarfism and narrow, epinastically curled leaves. These phenotypes were found to be caused by a reduction in cell number and cell size on the adaxial and abaxial sides of the epidermis, with a greater reduction on the abaxial side of the leaves. These phenotypic characteristics, combined with the more wavy morphology of epidermal cells in overexpression lines, indicate that CmDLC overexpression affects cell elongation and cell morphology. To investigate intracellular protein localization, a CmDLC-GFP fusion protein was made and expressed in onion epidermal cells. This protein was observed to be preferentially localized close to the cell membrane. Thus, we report here a new plant-specific gene that is localized to the cell membrane and that controls leaf cell number, size and morphology.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 추계학술대회 논문집
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• pp.725-726
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• 2012

• Applied Microscopy
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• 제44권2호
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• pp.68-73
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• 2014

With wide use of nano-materials, it is increasingly important to address their potential toxicity to mammalian cells. However, toxic effects of these materials have been mainly assessed by the cell survival assays. Considering that mitochondrial morphology and quality are highly sensitive to the condition of the cells, and the impairment of mitochondrial function greatly affect the survival of cells, here we tested the impact of multi-walled carbon nanotubes (MWNT) on the survival, mitochondrial morphology, and their membrane potential in HeLa cells. Interestingly, although MWNT did not induce cell death until 24 hours as assessed by pyknotic cell assay, mitochondrial length was elongated and the mitochondrial membrane potential was significantly reduced by exposure of HeLa cells to MWNT. These results suggest that MWNT exposure is potentially harmful to the cell, and the mechanism how MWNT alters mitochondrial quality should be further explored to assess the safety of MWNT use.

• 미생물학회지
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• 제10권1호
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• pp.29-34
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• 1972

The present study is of ultra-fine structure of Cryptococcus neoformans by means of electron microscopy and reveals the following : 1) In constrast to the bacteria, the normal Cryptococcus neofrmans contains nuclear enveloped with nuclear menbrane, mitochondria, endoplasmic reticulum, distinct cell wall and cell membrane, vacuoles and storage granules as observed in the eucaryotic cells. 2) In apparent cell walls and cell membrane with the appearance of electron transparent area (ETA) and changes of cell morphology were observed in the ultra-violet ray irradiated cell. 2) In apparent cell walls and cell membrance with the appreance of electron transparent area (ETA) and changes of cell morphology were observed in the ultra-violet ray irradiated cell. 3) Morphology changes and cytoplasmic element abnormality was increased with irradiated time. 4) Increase of electron transparent area was thought to be associated with degradation of cell.