• YAKHAK HOEJI
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• v.42 no.2
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• pp.175-180
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• 1998

Bifidobacterium bifidum OFR9 that exhibits acquired resistance to rifampicin and fluoroquinolones was selected by MNNG and multi-step mutation method. To investigate the resistance mechanism to rifampicin in the strain, RNA polymerase from B. bifidum parent strain and rifampicin-resistance OFR9 was partially purified and its sensitivity to rifampicin was assayed. The profile of RNA polymerase preparation of B. bifidum parent and B. bifidum OFR9 is similar to that of E. coli RNA polymerase that includes the basic subunits of ${\beta}$`, ${\beta},\;{\sigma},\;{\alpha}$ but which are a little different in size when they are compared with E. coli RNA polymerase subunits. RNA polymerase isolated from the parent strain was inhibited by 1${\mu}$g/ml rifampicin but that from B. bifidum OFR9 was not affected by 100${\mu}$g/ml concentration of rifampicin. RNA polymerase activity of B. bifidum OFR9 was maintained over 90% through that rifampicin concentration. This result is consistent with MIC values of in vitro test. It can be concluded that the mechanism of rifampicin resistance in B. bifidum OFR9 is due to an alteration of RNA polymerase.

• YAKHAK HOEJI
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• v.43 no.1
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• pp.124-127
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• 1999

Bifidobacterium infantis K-525 isolated from healthy Korean was susceptible to rifampicin and fluoroquinolones and resistant to other antituberculosis agents. When the preparation of this strain is taken as a therapeutics for human intestinal disorders with rifampicin or fluoroquinolones, its therapeutic effect can not be expected. So, B, infantis RFR-525 resistant to rifampicin was obtained by treating the parent B. infantis 525 with N-methyl-N'-nitro-N-nitrosoguanidine. B. infantis OFR-525 was produced by serial passage of B. infantis RFR-525 on agar with 2-fold minimal inhibitory concentration of ofloxacin. B. infantis OFR-525 was resistant to antituberculosis agents and fluoroquinolones up to 4∼128 fold higher than that for the original strain. The resistance of B. infantis OFR-525 against rifampicin and ofloxacin was maintained in vivo and in vitro. Conclusively, B. infantis OFR-525 can be regarded as a promising strain which can be developed as the preparation for the treatment of the intestinal disorders of the tuberculosis patients under rifampicin and ofloxacin therapy.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.7
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• pp.839-846
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• 1999

This paper presents an efficient algorithm for determining the location, size and number of capacitors in unbalanced radial distribution system. The objective function formulated consists of two terms: cost for energy loss and cost related to capacitor purchase and capacitor installation. The cost function associated with capacitor placement is considered as step function due to banks of standard discrete capacities. Genetic algorithms(GA) are used to obtain the population is derived. The strings in each population consist of the bus number index and size of capacitors to be installed. In order to determine the number of capacitor placement, the length mutation operator is used. Its efficiency is proved through the application in unbalanced radial distribution systems made of 10 buses with 9 distribution lines and 25 buses with 24 distribution lines.

• YAKHAK HOEJI
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• v.40 no.3
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• pp.351-356
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• 1996

The preparation of Enterococcus faecalis RSI is used as a therapeutics for human intestinal disorders. However, the microbe in this preparation is usually very sensitive to rifampicin and fluoroquinolones. If this preparation is taken with rifampicin or fluoroquinolones, its therapeutic effect can not be expected. E. faecalis RFR11, containing resistance to rifampicin was obtained by MNNG mutation method. Serial passage of E. faecalis RFR11 produced E. feacalis OFR16 on agar with 2-fold minimal inhibitory concentration of ofloxacin produced. E. feacalis OFR16 was resistant to fluoroquinolones up to 8-256 fold higher than that for the original strain. E. faecalis OFR16 also exhibited identical characteristics with the parent strain when they were tested for lactic acid formation and growth inhibition of E. coli MB4-5737 and Shigella sonnei MB4-10411. From in vitro test, it was identified that rifampicin and ofloxacin is not inactivated by certain factors of E. faecalis OFR16. Conclusively. E. faecalis OFR16, rifampicin and fluoroquinolones resistant mutant, is an efficient strain that has insensitivity against rifampicin and fluoroquinolones and original biochemical characteristics of the parent strain.

• YAKHAK HOEJI
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• v.38 no.6
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• pp.763-769
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• 1994

Bifidobacterium bifidum, one strain of medical preparation being on the market for human intestinal disorders, was sensitive to rifampicin and fluoroquinolones. If this preparation is taken with rifampicin and fluoroquinolones, its therapeutic effect can't be expected. Serial passage of B. bifidum RFR61, which was obtained by MNNG mutation method, on agar with 2-fold minimal inhibitory concentration of ofloxacin produced B. bifidum OFR9 with minimal inhibitory contentrations of fluoroquinolones up to $4{\sim}256-fold$ higher than that for the original strain. B. bifidum OFR9 produced almost the same amount of organic acid as parental strain. This strain showed growth inhibitory activity against E. coli NM522, Shigella dysenteriae ATCC9752 and E. coli 078. No inactivations of rifampicin and ofloxacin by this resistant mutant strain were found.

• Journal of Mechanical Science and Technology
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• v.19 no.5
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• pp.1072-1079
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• 2005

Conceptual design is the first step in the overall process of product design. Its intrinsic uncertainty, imprecision, and lack of information lead to the fact that current conceptual design activities in engineering have not been computerized and very few CAD systems are available to support conceptual design. In most of the current intelligent design systems, approach of principle synthesis, such as morphology matrix, bond graphic, or design catalogues, is usually adopted to deal with the concept generation, in which optional concepts are generally combined and enumerated through function analysis. However, as a large number of concepts are generated, it is difficult to evaluate and optimize these design candidates using regular algorithm. It is necessary to develop a new approach or a tool to solve the concept generation. Generally speaking, concept generation is a problem of concept synthesis. In substance, this process of developing design candidate is a combinatorial optimization process, viz., the process of concept generation can be regarded as a solution for a state-place composed of multi-concepts. In this paper, genetic algorithm is utilized as a feasible tool to solve the problem of combinatorial optimization in concept generation, in which the encoding method of morphology matrix based on function analysis is applied, and a sequence of optimal concepts are generated through the search and iterative process which is controlled by genetic operators, including selection, crossover, mutation, and reproduction in GA. Several crucial problems on GA are discussed in this paper, such as the calculation of fitness value and the criteria for heredity termination, which have a heavy effect on selection of better concepts. The feasibility and intellectualization of the proposed approach are demonstrated with an engineering case. In this work concept generation is implemented using GA, which can facilitate not only generating several better concepts, but also selecting the best concept. Thus optimal concepts can be conveniently developed and design efficiency can be greatly improved.

• YAKHAK HOEJI
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• v.41 no.4
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• pp.450-455
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• 1997

The preparation of Bacillus coagulans is used as a therapeutics for human intestinal disorders. However, the bacterium in the preparation is very susceptible to rifampic in and fluoroquinolones. When the preparation is taken with rifampicin or fluoroquinolones, its therapeutic effect can not be expected. So B. coagulans RFR17 resistant to rifampicin was obtained by treating the parent B. coagulans with N-methyl-N'-nitro-N-nitrosoguanidine. B. coagulans OFR17 was produced by serial passage of B. coagulans RFR17 on agar with 2-fold minimal inhibitory concentration of ofloxacin or ciprofloxacin. B. coagulans OFR17 was resistant to fluoroquinolones up to 16~64 fold higher than that for the original strain. B. coagulans OFR17 also exhibited identical characteristics with the parent strain when they were tested for lactic acid production and growth inhibition of E. coli MB4-01 and Shigella sonnei MB4-10411. From in vitro test, it was also identified that rifampicin and ofloxacin are not inactivated by certain factors of B. coagulans OFR17. Conclusively, B. coagulans OFR17 can be regarded as a promising strain which can be developed as the preparation for the treatment of the intestinal disorders of the tuberculosis patients under rifampicin and ofloxacin therapy.