• Molecules and Cells
• /
• v.27 no.2
• /
• pp.135-142
• /
• 2009

The centrosome, an organelle comprising centrioles and associated pericentriolar material, is the major microtubule organizing center in animal cells. For the cell to form a bipolar mitotic spindle and ensure proper chromosome segregation at the end of each cell cycle, it is paramount that the cell contains two and only two centrosomes. Because the number of centrosomes in the cell is determined by the number of centrioles, cells have evolved elaborate mechanisms to control centriole biogenesis and to tightly coordinate this process with DNA replication. Here we review key proteins involved in centriole assembly, compare two major modes of centriole biogenesis, and discuss the mechanisms that ensure stringency of centriole number.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.23 no.3
• /
• pp.243-250
• /
• 2020

Purpose: Gastric delta cells (D-cells), which are somatostatin-secreting cells, are the main paracrine inhibitor of acid secretion. The number of D-cells was studied in children presenting with upper gastrointestinal (UGI) disease. Methods: We retrospectively investigated the number of D-cells in the gastric body and antrum through immunofluorescence examinations according to symptoms, endoscopic findings, and Helicobacter pylori infection in 75 children who visited Hanyang University Hospital Pediatrics. Results: The mean patient age was 12.2±3.3 years. The male-to-female ratio was 1:1.4. The mean D-cell number per high-power field in the antrum and body was 20.5 and 12 in children with substernal pain, 18.3 and 10.3 in vomiting, 22.3 and 6 in diarrhea, and 9.3 and 6 in abdominal pain, respectively (p>0.05). According to endoscopic findings, the mean D-cell number in the antrum and body was 14.3 and 6 with gastritis, 14 and 9.3 with reflux esophagitis, 16.7 and 8.7 with duodeno-gastric reflux, 19.3 and 12.7 with gastric ulcer, 16 and 13.7 with duodenitis, and 12.3 and 4 with duodenal ulcer, respectively (p>0.05). The D-cell number in the gastric body was 2.7 and 8.7 in children with current H. pylori infection and non-infected children, respectively (p=0.01), while those in the antrum were 15.5 and 14, respectively, with no statistical significance. Conclusion: The D-cell number was lower in the gastric body of children with current H. pylori infection. Further studies concerning peptide-secreting cells with a control group would provide information about the pathogenic pathways of UGI disorder.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.20 no.3
• /
• pp.685-689
• /
• 2006

In order to examine the injury of vascular endothelial cells related with oxidative stress of reactive oxygen species(ROS), mophological changes of vascular endothelial cells were observed by light microscope after bovine pulmonary vascular endothelial cell line (BPVEC) was treated with 15 uM of hydrogen peroxide. In addition, the effect of vitamin E against ROS-induced oxidative stress was examined by light microscope. In this study, the cell number of BPVEC treated with ROS has significantly decreased than that of control, and the loss of cytoplasmic processes and cell swelling were observed in BPVEC treated with ROS. Whereas, cell number of BPVEC treated with vitamin E has significantly increased than that of BPVEC treated with ROS and also, cytoplasmic processes of BPVEC treated with vitamin E were preserved as control. These findings suggested that not only did ROS induce damage of BPVES by decrease of cell number, loss of cytoplasmic processes and cell swelling, but vitamin E also has protective effect against ROS-induced oxidative stress in cultures of BPVEC.

• Journal of Embryo Transfer
• /
• v.11 no.1
• /
• pp.41-50
• /
• 1996

This experiment was carried out to investigate the ovarian responses of the ovulation point, ovarian weight and size, the number of ovarian follicles and collected embryos, and to study the effects of the developmental stages (oocytes, 2-4 cell. 8-16 cell and morulae), additional levels of Ficoll (0, 15, 30%) on the survival rate (FDA-test) of rat embryos frozen in vitrification solution (20% glycerol + 10% ethylene glycol + 10% sucrose). Sunanarized results was as follows; 1. The mean ovulation point per head was 7, and the weight of ovaries was 0.03g. The size of ovary was 5.9 mm(L) and 4.6 mm(W), and the number of ovarian follicles over and below 2 mm was 4.7 and 8.7, respectively. The number of the collected embryos per head was 5.5 (79%). 2. 2. The FDA score of embryos frozen in 20 G 10 E 10 S without Ficoll was 2.8 (oocyte), 2.6 (2-4 cell), 3.9 (8-16 cell) and 3.6 (morula), respectively. However, there were no significant differences among treatments. 3. The FDA score of embryos frozen in 20 G 10 E 10 S with 15% Ficoll was 3.4 (oocyte), 4.0 (2-4 cell), 4.7 (8-16 cell) and 4.8 (morulae), respectively (P>0.05). 4. The FDA score of embryos frozen in 20 G 10 E 10 S with 30 % Ficoll was 3.7 (oocyte), 3.2 (2-4 cell), 4.4 (8-16 cell) and 4.4 (morulae), respectively (P>0.05). 5. As shown in the above results, the higher survival rate was obtained in the treatment of 15% Ficoll than that of 30%. And the survival rate (FDA-test)of the oocytes and 2-4 cell stages of the rat embryos was lower than that of 8~16 cell and morulae stages. It was considered that 8-16 cell and morulae could be available for the successful freezing by vitrification of rat embryos with 15% Ficoll except for oocytes.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.43 no.1
• /
• pp.1-6
• /
• 2020

Fast service access involves keeping track of the location of mobile users, while they are moving around the mobile network for a satisfactory level of QoS (Quality of Service) in a cost-effective manner. The location databases are used to keep track of Mobile Terminals (MT) so that incoming calls can be directed to requested mobile terminals at all times. MT reporting cell system used in location management is to designate each cell in the network as a reporting cell or a non-reporting cell. Determination of an optimal number of reporting cells (or reporting cell configuration) for a given network is reporting cell planning (RCP) problem. This is a difficult combinatorial optimization problem which has an exponential complexity. We can see that a cell in a network is either a reporting cell or a non-reporting cell. Hence, for a given network with N cells, the number of possible solutions is 2^N. We propose a biogeography based optimization (BBO) for design of mobile station location management system in wireless communication network. The number and locations of reporting cells should be determined to balance the registration for location update and paging operations for search the mobile stations to minimize the cost of system. Experimental results show that our proposed BBO is a fairly effective and competitive approach with respect to solution quality for optimally designing location management system because BBO is suitable for combinatorial optimization and multi-functional problems.

• Korean Journal of Veterinary Research
• /
• v.29 no.2
• /
• pp.51-57
• /
• 1989

This study was performed to investigate the toxicity of ochratoxin A (OA) to the chromosomes of $K_{562}$ tumor cell-line in vitro. The results of this experiment were as follows: 1) Chromosomes of $K_{562}$tumor cell-line resulted in pseudotriploidy on the control group. Chromosomes of $K_{562}$ tumor cell-line treated with OA resulted in heteroploidy compared with the control group. The mean number of chromosomes in the karyotype of the control group (60) were 7 in the A group, 5 in the B group, 20 in the C+X group, 7 in the D group, 9 in the E group, 6 in the F group, and 6 in the G+Y group respectively. The number of chromosomes were increased as follows: Treating with $0.7{\mu}M$ OA, the number of chromosomes were increased one in E and F group, two in G+Y group compared with control group. In treated with $1.5{\mu}M$ OA, the increasing number of chromosome was one in E and F group. In treated with $3{\mu}M$ OA, E and F group was increased one and G+Y group were increased two chromosomes compared with control group. But in treated with $6{\mu}M$ OA, the number of chromosome in G+Y group was decreased one. 2) $K_{562}$ tumor cell line treated with OA showed Philadelphia-Chromosome in the long arm of the G group karyotype chromosome. The rate of chromosome aberration in $K_{562}$ tumor cell-line treated with OA was 77% in $0.7{\mu}M$ OA group, 71% in $1.5{\mu}M$ OA group, 82% in $3{\mu}M$ OA group and 94% in $6{\mu}M$ OA group respectively. The rate of chromosome aberration of $K_{562}$ tumor cell-line treated with OA was high in the high dose level of OA, and chromosome aberration of $K_{562}$ tumor cell-line treated with OA showed deletion, minute, dicentric-chromosome and translocation in the long arm of the C-group karyotype. As a result of this study, the toxicity of OA showed deletion, minute, dicentric-chromosome and translocation in the long arm of the C-group karyotype, and then, the toxicity of OA resulted in the damage to RNA and protein synthesis in $K_{562}$ tumor cell-line, and the C-group karyotype of $K_{562}$ tumor cell-line was target of the toxicity of OA.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.12A
• /
• pp.962-970
• /
• 2009

This paper proposes a self-organizing scheme which collects the information of neighboring cells, and then assigns a Physical Cell Identifier (PCI) for a newly deployed cell in LTE systems. The number of PCIs are limited, so the reuse of PCIs in different cells is unavoidable. In a dense urban environment where many small cells such as Pico/Femto cells are deployed under macro cells, it is expected that the number of PCIs becomes more limited. Therefore, the limited number of PCIs needs to be allocated very efficiently. We propose a PCI allocation scheme for a newly deployed cell that can autonomously select a PCI to increase PCI reuse efficiency by utilizing the levels of received signal strength from neighboring cells. To evaluate the performance of the proposed scheme, simulations have been developed and performed with two scenarios on the coverage types of newly deployed cells. When the proposed scheme is applied, the simulation results show that the number of PCIs required for the operation of the system can be saved so that PCIs can be efficiently reused.

• Restorative Dentistry and Endodontics
• /
• v.16 no.2
• /
• pp.62-84
• /
• 1991

The purpose of this study was to evaluate the cytotoxicity of four root canal sealers(Tubliseal, AH26, Apatite Root Canal Sealer I, Apatite Root Canal Sealer II) in Vitro. The root canal sealers were mixed and filled in molds which were $14{\times}1.25mm$ in diameter, in height to use for cell counting and agar overlary method, and $7{\times}1.25mm$ for millipore filter method and set for 7 days to use for experiment. Silicone and copper plate were used for negative and positive control respectively. Using the culture of L929 fibroblast, total cell number and vital cell number were counted and the ratio of vital cell number to total cell number was calculated on 2 nd, 4 th, 6 th experimental day, and the change of cell membrane permeability was tested by agar overlay method, and the succinate dehydrogenase activity was tested by millipore filter method. The obtained results were as follows. 1. In ail experimental groups, the mitotic activity of fibroblast was reduced when compared with that of negative control group, so ail experimental groups showed cytotoxicity. Apatite Root Canal Sealer I group exhibited mild cytotoxicity, and Tubliseal, AH26, Apatite Root Cenal Sealer II groups exhibited severe cytotoxicity. 2. In the test of the change of cell membrane permeability by agar overlay method, all experimental groups showed cytotoxicity. AH26 group exhibited mild cytotoxicity, and Apatite Root Canal Sealer I group exhibited moderate cytotoxicity, and Tubliseal and Apatite Root Canal Sealer II group exhibited severe cytotoxicity. 3. In the test of SDH activity by millipore filter method, there was no cytotoxicity in Apatite Root Canal Sealer I and Apatite Root Canal Sealer II group, but Tubliseal and AH26 group showed mild cytotoxicity.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.3
• /
• pp.627-631
• /
• 2009

This paper presents a novel current steering cell matrix DAC(digital-to-analog converter) architecture to reduce decoder area. The current cell matrix of a existing architecture is selected by columns and lows thermometer code decoder of input bits. But The current cell matrix of a proposal architecture is divided 2n by the thermometer code decoder of upper input bits and are selected by the thermometer code decoder of middle and lower input bits. Because of this configuration, decoder numbers have increased. But the gate number that composed of decoder has decreased. In case of the designed 8 bit current steering cell matrix DAC, the gate number of decoder has decreased by about 55% in comparison with a existing architecture.

• Proceedings of the KSAR Conference
• /
• 2001.10a
• /
• pp.3-4
• /
• 2001

Normal cells proliferate generally a limited number doublings in culture and only rarely have they been shown to overcome cellular senescence and crisis stages, and immortalize spontaneously. I have established a number of non-chemically and non-chemically immortalized embryo fibroblastic (EF) cell lines in continuous cell culture. These include the spontaneously immortalized cell line, DF-1 and several immortal EF cell lines derived from various embryonic tissues. I have previously demonstrated that all of the immortal EF cells established have rapid cell proliferation capacity compared to primary EF cells, presumably due to the deregulation of cell cycle regulators such as p53, E2F-1 and the numerous cyclins. DF-1 cells, in particular, were shown to proliferate more rapidly under normal culture conditions compared to other immortal EF cells, implicating other mechanisms may be important for regulating their growth. The possible mechanism(s) underlying the accelerated growth of DF-1 cells will be addressed in this study. (omitted)