• Journal of Microbiology
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• v.34 no.4
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• pp.341-348
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• 1996

The regulation of xylE gene expression was examined by using vector promoter and construction of genetically engineered microorganisms (GEMs) for application in microcosm. When the xylE gene wsa subcloned into pBluscript SK(+) under the control of lac promoter (pTY1) in E. coli, and the expression was induced by IPTG, the enzyme activity of catechol 2, 3-dioxygenase was increased 4.7 times more than that of the crude extracts from transformants harboring pTY1. We suggest that the xylE gene has its own promoter at the upstream portion, because it was able to be expressed even in the absence of IPTG. A recombinant plasmid, pSW3a harboring the xylE gene under the T7 promotor, showed the activity of 14.5 units/mg protein, higher than that of parental strain, E. coli PYT1. The xylE gene in recombinant plasmid pSW3a was used as reporter gene for the application in microcosm ecosystem, since it was used for detection of xylE-positive clones by catechol spray on the agar plates. The pSW3a in E. coli was introduced into Pseudomonas patida to construct GEM strain, and examined for the exxpression and functional stability in microcosms.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.488-495
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• 2017

In this study, we conducted the kinetic hydration modeling of OPC and the final product according to the substitution ratio of GGBS by using the geochemical code, GEMS, in order to calculate the thermodynamic equilibrium. The thermodynamic data was used by GEMS's 3rd party database, Cemdata18, and the cement hydration model, the Parrot & Killoh model was applied to simulate the hydration process. In OPC modeling, ion concentration of pore solution and hydration products by mass and volume were observed according to time. In the GGBS modeling, as the substitution rate increases, the amount of C-S-H, which contributes the long-term strength, increases, but the amount of Portlandite decreases, which leads to carbonation and steel corrosion. Therefore, it is necessary to establish prevention of some deterioration.