• Proceedings of the PSK Conference
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• 2002.10a
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• pp.328.1-328.1
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• 2002

A major lipid-signaling pathway in mammalian cells implicated the activation of sphingomyelinase (SMase), which hydrolyses sphingomyeline to generate ceramide and phosphocholine. Sphingomyelinase is divided into many isoform groups dependent on optimal pH, and essential cation especially magnesium in their activation. Such as acidic sphingomyelinase, neutral sphingomyelinase and alkaline sphingomyelinase. Ceramide is known as a crucial second messenger in cell responses like cell proliferation. cell cycle arrest. cellular senescence, and apoptosis. (omitted)

• Biomedical Science Letters
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• v.2 no.1
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• pp.57-69
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• 1996

To examine the process of spermiogenesis in the Korean red-backed vole, Clethrionomys rufocanus regulus, the seminiferous epithelium in the testis, was studied by trasmission electron microscopy, and the following results were obtained based on the morphological characteristics of cell differentiation. 1. According to the fine structural differentiation, spermiogenesis was divided into Golgi, cap, acrosome, maturation and spermiation phases. Besides, these phases were sub-divided into two steps : early and late phases respectively, Thus, the spermiogenesis of Clethrionomys rufocanus regulus was divided into a total of ten steps. 2. In the changes of the chromatin, the chromatin granules began to be condenced in the late Golgi phase, regularizated at maturation phases, and a perfect nucleus of sperm was formed at the spermiation phases. 3. The sperm head had the falciform, and the formative period of sperm tail began to be develop in the early Golgi phase and completed at the spermiation phases. 4. In the morphological features of spermiation phases, the spermatid of early spermiation phase was divided into three types : (1) A-type spermatid contained cytoplasmic droplets in the neck region and middle piece, and the mitochondria was irregular, and arranged around the axoneme. (2) B-type contained cytoplasmic droplet in the middle piece only, and the mitochondria are arranged the center of axoneme regularly, and (3) In the C-type spermatid, the arrangement of mitochondria was regular, and was contained cytoplasmic droplet in the neck region only. In the late spermiation phase, only the sperm head was surrounded by cytoplasm of Sertoli cell or the matured sperm just before the spermiation from the cytoplasm of Sertoli cell.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.12
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• pp.9-24
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• 1995

In this paper, we proposed and analysed two kinds of priority control mechanism to archive the cell loss rate requirement and the delay requirement of each class. The service classes of our concern are the high time priority class(class 1) and the high loss priority class(class 2). Two kinds of priority control mechanism is divided by the method of storing the arriving class 2 cell in buffer on case of buffer full. The first one is the method which discarding the arriving class 2 cell, the second one is the mothod which storing the arriving class 2 cell on behalf of pushing out the class 1 cell in buffer. In the proposed priority schemes, one cell of the class 1 is transmitted whenever the maximum K cells of the class 2 is transmitted on case of transmitting the class 1 cell and the class 2 cell sequentially. In this paper, we analysed the cell loss rate and the mean cell delay for each class of the proposed priority scheme by using the Markov chain. The analytical results show that the characteristic of the mean cell delay becomes better for the class 1 cell and that of the cell loss rate becomes better for the class 2 cell by selecting properly the cell transfer ratio according to the condition of input traffic.

• Korean Chemical Engineering Research
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• v.48 no.2
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• pp.275-282
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• 2010

A characteristic study of aqueous chlorine dioxide generation from sodium chlorite($NaClO_2$) by an undivided electrochemical cell with different anode materials were performed. $IrO_2$-coated Ti, $RuO_2$-coated Ti and DSA were used as anode materials and Pt-coated Ti electrode was used as cathode. Various electrochemical cell operating parameters such as cell residence time($t_R$), initial feed solution pH, sodium chlorite and sodium chloride(NaCl) concentration and applied current for the generation of chlorine dioxide in an un-divided cell were investigated and optimized. Estimated optimal cell residence times in $IrO_2$-coated Ti, $RuO_2$-coated Ti and DSA anode material systems were around 2.27, 1.52 and 1.52 sec, respectively. Observed optimum initial feed solution pH was around 2.3 in all anode material systems. Optimum sodium chlorite concentrations in $IrO_2$-coated Ti, $RuO_2$-coated Ti and DSA anode systems were around 0.43, 0.43 and 0.32 g/L, respectively. Optimum electrolyte concentration and applied current were around 5.85 g/L and 0.6 A in all anode systems. Current efficiencies of $IrO_2$-coated Ti, $RuO_2$-coated Ti and DSA anode systems under optimum conditions were 79.80, 114.70 and 70.99%, respectively. Obtained energy consumptions for the optimum generation of chlorine dioxide were 1.38, 1.03 and $1.61W{\cdot}hr/g-ClO_2$, respectively.

• Journal of Nutrition and Health
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• v.31 no.1
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• pp.21-27
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• 1998

The objective of this study was to observe the effect of dietary calcium(Ca) level on colonic mucosal levels of cell proliferation, 1, 2-diacylglycerol(DAG), TXB2, PGE2 and phospholipid fatty acid composition which have been known as biomarkers for colon cancer. One hundred male Sprague Dawley rats, at 7 weeks of age, were divided into two fat type groups. Each group of which was further divided into two Ca level groups. Each rt was intramuscularly injected with 1, 2,-dimenthylhydrazine(DMH) for 6 weeks (total dose of 180mg/kg body weight) and simultaneously fed one of four experimental diets containing 15% dietary fat(corn oil or perilla oil )and 0.3% or 1.0% Ca by weight for 20 weeks. Compared to corn oil, perilla oil significantly reduced cell proliferation by decreasing labeling index, proliferating zone, crypt length in colonic mucosa and colonic mucosa and colonic mucosal levels of DAG, TXB2 . PGE2 and phospolipid (PL) arachidonic acid distribution. The effect of Ca on biomarketrs was different depending on the type of dietary fat comsumed . Ca effect of Ca on biomarkers was different depending on the type of dietary fat comsumed. Ca effect was not significantly shown in the PO group, but it was significant in the CO group in which high Ca(1.0%) decreased the levels of levels of PL-C20 : 4(%), DAG and PGE2 . However , high Ca supplementation had shown only the trends of improving cell proliferation. Overall , high dietary Ca significantly reduced cell proliferation by inhibiting the synthesis of eicosanoid and DAG with reduced distribution of PL-C20 : 4 , which may have resulted in lower activation of PKC through reduced signal transduction. Since a high level of dietary Ca was more effective in reducing the risk factor against colon cancer in corn oil fed rats, it could be suggested that a higher amount of dietary Ca be consumed , especially when more vegetable oil rich in linoleic acid is included in the diet.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.4
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• pp.521-525
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• 2011

It is known that the low-intensity sound stimulation really affect to grow the cell. The cellular growth mechanism, however, does not been clearly identified even the effect on the low-intensity sound stimulation. The purpose of this study is to investigate the effect of low-intensity sound stimulation on the alveolar UC-MSC proliferation. Before the low-intensity sound stimulation is applied, the UC-MSC are cultured for 24 hours to facilitate their attachments. The cells are divided into two groups. And each was exposed to a medium with or without the low-intensity ultrasound stimulation at 71dB intensity level. The UC-MSC are again divided into three treatment groups of group 1, 2, and 3 and exposed to a frequency at 50Hz, 100Hz, and 1000Hz, respectively. In the results, it is investigated that the growth rates of UC-MSC for the stimulated groups were higher than those of control groups. In 1000Hz frequency, the number of UC-MSC cell is significantly higher than control groups (p>0.05). We would put the hypothesis that the cell growth could be enhanced by an appropriate low-intensity sound stimulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.12
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• pp.3256-3264
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• 1996

This paper presents an efficient VLSI architecture for transposing matris in high speed. In the case of transposing N*N matrix, N$^{2}$ numbers of transposition cells are configured as regular and spuare shaped structure, and pipeline structure for operating each transposition cell in paralle. Transposition cell consists of register and input data selector. The characteristic of this architecture is that the data to be transposed are divided into several bundles of bits, then processed serially. Using the serial transposition of divided input data, hardware complexity of transpositioncell can be reduced, and routing between adjacent transposition cells can be simple. the proposed architecture is designed and implemented with 0.5 .mu.m VLSI library. As a result, it shows stable operation in 200 MHz and less hardware complexity than conventional architectures.

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

• Applied Microscopy
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• v.13 no.1
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• pp.63-70
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• 1983

The cell division of Bacillus thuringiensis are studed by a electron microscope. It was observed that when the cell division was occurred, the bacterial transverse septeum was centripetally formed, and the bacterial spore was divided into two daughter cells. The fore spore septum was initiated by invagination from either sides of the cell membranes, and was easily distinguished it from the transverse septum of the vegetative cell division. The large vesicular mesosome was. observed at one end of the cell membrane. The nucleoids were of variously irregular shapes and had no a nuclear membrane. The morphology of the bacteria was visualizd by a scanning electron microscope. The surface of the cell was generally rough and had a single polar flagellum, which was appeared to be $0.2{\mu}$ in width and $13{\mu}$ in length.

• Korean Journal of Community Nutrition
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• v.17 no.2
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• pp.243-257
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• 2012

The purpose of this study was to evaluate pancreatic ${\beta}$-cell function of Korean adult and to examine the associations between ${\beta}$-cell function and nutrient intakes. Data were analyzed for 1,917 male and 2,885 female subjects older than 30 years using 'The Forth Korean National Health and Nutrition Survey in 2009'. We calculated HOMA ${\beta}$-cell (The homeostasis model assessment of ${\beta}$-cell function) using fasting glucose and fasting insulin for assessing ${\beta}$-cell function. Subjects were divided into HHG (High HOMA ${\beta}$-cell Group) or LHG (Low HOMA ${\beta}$-cell Group) according to median of HOMA ${\beta}$-cell, and then nutrient intakes were compared between two groups. In the entire study population, HHG showed lower percent of carbohydrate intakes (p < 0.05), and higher fat (p < 0.01), percent of fat (p < 0.05), vitamin A (p < 0.05), carotene (p < 0.05) and riboflavin (p < 0.05) intakes than LHG. In addition, levels of HOMA ${\beta}$-cell were negatively correlated with percent of carbohydrate (${\beta}$ = -0.040, p < 0.05), and positively correlated with percent of fat (${\beta}$ = 0.046, p < 0.01). The subjects were then divided into two subgroups according to body mass index values, either $23kg/m^2$ (under- and normal-weight) or ${\geq}23kg/m^2$ (over-weight and obese). Significant differences of some nutrients intakes and correlations with HOMA ${\beta}$-cell were observed only in under- and normal weight subjects, but not in over-weight and obese subjects. In conclusion, high carbohydrate, lower fat and lower vitamin intakes may be related with pancreatic ${\beta}$-cell dysfunction in under- and normal-weight Korean.