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정병창,김현회,박용현 대한비뇨의학회 2009 Investigative and Clinical Urology Vol.50 No.10
Purpose: Recently, the whole DNA sequence of Bacillus subtilis (B. subtilis) was identified, revealing the existence of the YvrK gene encoding a 43 kD oxalate decarboxylase (OXDC), which degrades oxalate by a simple pathway. The objective of this study was to develop recombinant Escherichia coli (E. coli) expressing the Yvrk gene from B. subtilis. Materials and Methods: After the extraction of total DNA from B. subtilis, the YvrK gene was cloned by polymerase chain reaction. The cloned DNA encoding OXDC was inserted into the pBAD/gIII-A vector, downstream of the L-arabinose promotor. The plasmid vector was transformed into TOP 10 E. coli, and the transformants were selected with ampicillin. The recombinant E. coli, named pBy, was then analyzed by DNA sequencing and Western blot. To evaluate the oxalate-degrading function of pBy, pBy was cultured in LB broth containing oxalate, and then the amount of oxalate in the medium was assessed. The oxalate-degrading activity of homogenates of pBy was evaluated. Results: DNA sequencing showed the successful transformation of the YvrK gene into TOP 10 E. coli. Western blot analyses showed that pBy expressed OXDC. pBy removed oxalate during the overnight culture in oxalate-containing LB broth, and the homogenate of pBy degraded 90% of oxalate under acidic conditions. Conclusions: A recombinant E. coli expressing the YvrK gene was successfully produced. The bacteria showed potent oxalate-degrading activity. The results of this study will provide a solution to the treatment of calcium oxalate stones and hyperoxaluria, for which there are few medical treatment modalities. Purpose: Recently, the whole DNA sequence of Bacillus subtilis (B. subtilis) was identified, revealing the existence of the YvrK gene encoding a 43 kD oxalate decarboxylase (OXDC), which degrades oxalate by a simple pathway. The objective of this study was to develop recombinant Escherichia coli (E. coli) expressing the Yvrk gene from B. subtilis. Materials and Methods: After the extraction of total DNA from B. subtilis, the YvrK gene was cloned by polymerase chain reaction. The cloned DNA encoding OXDC was inserted into the pBAD/gIII-A vector, downstream of the L-arabinose promotor. The plasmid vector was transformed into TOP 10 E. coli, and the transformants were selected with ampicillin. The recombinant E. coli, named pBy, was then analyzed by DNA sequencing and Western blot. To evaluate the oxalate-degrading function of pBy, pBy was cultured in LB broth containing oxalate, and then the amount of oxalate in the medium was assessed. The oxalate-degrading activity of homogenates of pBy was evaluated. Results: DNA sequencing showed the successful transformation of the YvrK gene into TOP 10 E. coli. Western blot analyses showed that pBy expressed OXDC. pBy removed oxalate during the overnight culture in oxalate-containing LB broth, and the homogenate of pBy degraded 90% of oxalate under acidic conditions. Conclusions: A recombinant E. coli expressing the YvrK gene was successfully produced. The bacteria showed potent oxalate-degrading activity. The results of this study will provide a solution to the treatment of calcium oxalate stones and hyperoxaluria, for which there are few medical treatment modalities.
정병창,이두호,윤병동,이수범 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.8
The performance of surface damping treatments may vary once the surface is exposed to a wide range of temperatures, because the performance of viscoelastic damping material is highly dependent on operational temperature. In addition, experimental data for dynamic responses of viscoelastic material are inherently random, which makes it difficult to design a robust damping layout. In this paper a statistical modeling procedure with a statistical calibration method is suggested for the variability characterization of viscoelastic damping material in constrained-layer damping structures. First, the viscoelastic material property is decomposed into two sources: (i) a random complex modulus due to operational temperature variability, and (ii) experimental/model errors in the complex modulus. Next, the variability in the damping material property is obtained using the statistical calibration method by solving an unconstrained optimization problem with a likelihood function metric. Two case studies are considered to show the influence of the material variability on the acoustic performances in the structural-acoustic systems. It is shown that the variability of the damping material is propagated to that of the acoustic performances in the systems. Finally, robust and reliable damping layout designs of the two case studies are obtained through the reliability-based design optimization (RBDO) amidst severe variability in operational temperature and the damping material.