• Title/Summary/Keyword: branching processes

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A transmission distribution estimation for real time Ebola virus disease epidemic model (실시간 에볼라 바이러스 전염병 모형의 전염확률분포추정)

  • Choi, Ilsu;Rhee, Sung-Suk
    • Journal of the Korean Data and Information Science Society
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    • v.26 no.1
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    • pp.161-168
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    • 2015
  • The epidemic is seemed to be extremely difficult for accurate predictions. The new models have been suggested that show quite different results. The basic reproductive number of epidemic for consequent time intervals are estimated based on stochastic processes. In this paper, we proposed a transmission distribution estimation for Ebola virus disease epidemic model. This estimation can be easier to obtain in real time which is useful for informing an appropriate public health response to the outbreak. Finally, we implement our proposed method with data from Guinea Ebola disease outbreak.

A Comparison of ROCK Inhibitors on Human Bone Marrow-Derived Mesenchymal Stem Cell Differentiation into Neuron-Like Cells

  • Lee, Hyun-Sun;Kim, Kwang-Sei;O, Eun-Ju;Joe, Young-Ae
    • Biomolecules & Therapeutics
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    • v.18 no.4
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    • pp.386-395
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    • 2010
  • Bone marrow-derived mesenchymal stem cells (BM-MSC) are a multipotent cell population that can differentiate into neuron-like cells. Previously it has been reported that murine BM-MSC can differentiate into neuron-like cells by co-treatment with a Rho-associated kinase (ROCK) inhibitor -Y27632 and $CoCl_2$. In this study, we compared several ROCK inhibitors for the ability to induce human BM-MSCs to differentiate into neuron-like cells in the presence of $CoCl_2$. Y27632 with high specificity for ROCK at 1-30 ${\mu}M$ was best at inducing neuronal differentiation of MSCs. Compared to HA1077 and H1152, which also effectively induced morphological change into neuron-like cells, Y27632 showed less toxicity even at 100 ${\mu}M$, and resulted in longer multiple branching processes at a wide range of concentrations at 6 h and 72 h post-induction. H89, however, which has less specificity by inhibition of protein kinase A, S6 kinase 1 and MSK1 with similar or greater potency, was less effective at inducing neuronal differentiation of MSCs. Simvastatin, which can inhibit Rho, Ras, and Rac by blocking the synthesis of isoprenoid intermediates, showed little activity for inducing morphological changes of MSCs into neuron-like cells. Accordingly, the expression patterns for neuronal cell markers,including ${\beta}$-tubulin III, neuron-specific enolase, neurofilament, and microtubule-associated protein, were consistent with the pattern of the morphological changes. The data suggest that the ROCK inhibitors with higher specificity are more effective at inducing neuronal differentiation of MSCs.

Analytical Study on the Discharge Transients of a Steam Discharging Pipe (증기방출배관의 급격과도현상에 대한 해석적 연구)

  • 조봉현;김환열;강형석;배윤영;이계복
    • Journal of Energy Engineering
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    • v.7 no.2
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    • pp.202-208
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    • 1998
  • As in the other industrial processes, a nuclear power plant involves a steam relieving process through which condensable steam is discharged and condensed in a subcooled pool. An analysis of steam discharge transients was carried out using the method of characteristics to determine the flow characteristics and dynamic loads of piping that are used for structural design of the piping and its supports. The analysis included not only the steam flow rate but also the flow rates of the air and water which originally exist in the pipe. The analytical model was developed for a uniform pipe with friction through which the flow was discharged into a suppression pool. Including the combinations of system elements such as reservoir, valve and branching pipe lines. The piping flow characteristics and dynamic loads were calculated by varying system pressure, pipe length, and submergence depth. It was found that the dynamic load, water clearing time and water clearing velocity at the water/air interface were dependent not only on the system pressure and temperature but also on the pipe length and submergence depth.

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NELL2 Function in Axon Development of Hippocampal Neurons

  • Kim, Han Rae;Kim, Dong Hee;An, Ji Young;Kang, Dasol;Park, Jeong Woo;Hwang, Eun Mi;Seo, Eun Jin;Jang, Il Ho;Ha, Chang Man;Lee, Byung Ju
    • Molecules and Cells
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    • v.43 no.6
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    • pp.581-589
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    • 2020
  • Neurons have multiple dendrites and single axon. This neuronal polarity is gradually established during early processes of neuronal differentiation: generation of multiple neurites (stages 1-2); differentiation (stage 3) and maturation (stages 4-5) of an axon and dendrites. In this study, we demonstrated that the neuron-specific n-glycosylated protein NELL2 is important for neuronal polarization and axon growth using cultured rat embryonic hippocampal neurons. Endogenous NELL2 expression was gradually increased in parallel with the progression of developmental stages of hippocampal neurons, and overexpression of NELL2 stimulated neuronal polarization and axon growth. In line with these results, knockdown of NELL2 expression resulted in deterioration of neuronal development, including inhibition of neuronal development progression, decreased axon growth and increased axon branching. Inhibitor against extracellular signal-regulated kinase (ERK) dramatically inhibited NELL2-induced progression of neuronal development and axon growth. These results suggest that NELL2 is an important regulator for the morphological development for neuronal polarization and axon growth.

International cyber security strategy as a tool for comprehensive security assurance of civil aviation security: methodological considerations

  • Grygorov, Oleksandr;Basysta, Albina;Yedeliev, Roman;Paziuk, Andrii;Tropin, Zakhar
    • International Journal of Computer Science & Network Security
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    • v.21 no.9
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    • pp.332-338
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    • 2021
  • Civil aviation cybersecurity challenges are global in nature and must be addressed using global best practices and the combined efforts of all stakeholders. This requires the development of comprehensive international strategies and detailed plans for their implementation, with appropriate resources. It is important to build such strategies on a common methodology that can be applied to civil aviation and other interrelated critical infrastructure sectors. The goal of the study was to determine the methodological basis for developing an international civil aviation cybersecurity strategy, taking into account existing experience in strategic planning at the level of international specialized organizations. The research was conducted using general scientific and theoretical research methods: observation, description, formalization, analysis, synthesis, generalization, explanation As a result of the study, it was established the specifics of the approach to formulating strategic goals in civil aviation cybersecurity programs in the documents of intergovernmental and international non-governmental organizations in the aviation sphere, generally based on a comprehensive vision of cybersecurity management. A comparative analysis of strategic priorities, objectives, and planned activities for their implementation revealed common characteristics based on a single methodological sense of cybersecurity as a symbiosis of five components: human capacity, processes, technologies, communications, and its regulatory support. It was found that additional branching and detailing of priority areas in the strategic documents of international civil aviation organizations (by the example of Cybersecurity Strategy and Cybersecurity Action Plan) does not always contribute to compliance with a unified methodological framework. It is argued that to develop an international civil aviation cybersecurity strategy, it is advisable to use the methodological basis of the Cyber Security Index.

Study on GO Dispersion of PC/GO Composites according to In-situ Polymerization Method (In-situ 중합방법에 따른 폴리카보네이트(PC)/그래핀 옥사이드(GO) 복합체의 GO 분산성 연구)

  • Lee, Bom Yi;Park, Ju Young;Kim, Youn Cheol
    • Applied Chemistry for Engineering
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    • v.26 no.3
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    • pp.336-340
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    • 2015
  • Three different types of polycarbonate (PC)/graphene oxide (GO) composites using diphenyl carbonate as a monomer were fabricated by melt polymerization. Those were the PC/GO composite (PC/GO) using a twin extruder, in-situ PC/GO composite (PC/GO-cat.) using a catalyst, and in-situ PC/GO composite (PC/GO-COCl) using a GO-COCl treated by -COCl, Chemical structures of the composites were confirmed by C-H and C=O stretching peak at $3000cm^{-1}$ and $1750cm^{-1}$, respectively. The slope for the storage (G') versus loss (G") modulus plot decreased with an increase in the heterogeneous property of polymer melts. So we can check the GO dispersion of the PC/GO composites using by the slop for G'-G" plot. According to the G'- G" slopes for three different types of PC/GO composites, GO was well dispersed within PC matrix in case of PC/GO and PC/GO-cat.. It was also confirmed by atomic force microscope (AFM) photos. One of the reasons for the poor GO dispersion of PC/GO-COCl is branching and crosslinking processes occurred during polymerization, which was further confirmed by a plot for the complex modulus versus phase difference.

Physicochemical Properties of Cowpea Crude and Refined Starch (동부 조전분 및 정제전분의 이화학적 특성)

  • 윤혜현;이혜수
    • Korean journal of food and cookery science
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    • v.3 no.1
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    • pp.31-36
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    • 1987
  • The purpose of this study is to investigate the physicochemcal Properties of the cowpea crude and refined starch and to present the basic data for physicochemical factor which gives the properties of Mook to cowpea starch gel. Water binding capacity of crude starch was 235. In and that of refined starch was 186.0%. The pattern of change in swelling power and solubility for increasing temperature started to increase at $60^{\circ}C$ and increased rapidly from $70^{\circ}C$, for both of crude and refined starch. The optical transmittance of 0.2% crude and refined starch suspensions were increased from $65^{\circ}C$ and showed rapid increasement during 68~$80^{\circ}C$, and their curves showed two-stage processes. The gelatinization pattern for 6n crude and refined starch suspensions were investigated by the Brabender amylograph. The corves showed the pasting temperature of $72.0^{\circ}C$ and $72.1^{\circ}C$, peak height of 11303.U. ($88.0^{\circ}C$) and 970 B.U. ($83.5^{\circ}C$) for crude and refined starch, respectively, and both showed high viscosities when cooling. Blue values for crude and refined starch were 0.369 and 0.376 respectively. Alkali number of crude and refined starch were 7.77 and 7.34, and reducing values were 3.60 and 2. 10, respectively. Amylose content of cowpea starch was 33.7%. Periodate oxidation of the starch fractions resulted that amylose had the average molecular weight of 23590, degree of polymerization of 146 and amylopectin had the degree of branching of 3.42, glucose unit per segment of 29.

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