Refolding of reduced and denatured protein in vitro has been an important issue for both basic research and applied biotechnology. Refolding at low protein concentration requires large volumes of refolding buffer. Among various refolding methods, diafiltration is very useful to control the denaturant and red/ox reagents in a refolding solution. We constructed a refolding procedure of high lysozyme concentration (0.5-10 mg/ml) based on the linear reduction of the urea concentration during diafiltration under oxygen pressure. When the urea concentration in the refolding vessel was decreased from 4 M with a rate of 0.167 M/h, the refolding yields were 85% and 63% at protein concentrations, 5 mg/ml and 10 mg/ml, respectively, after 11 h. This method gave a high productivity of 40.1,microM/h of the refolding lysozyme. The change in refolding yields during the diafiltration could be simulated using the model of Hevehan and Clark.
Metal-organic framework (MOF) compounds consisting of terephthalic acid and cations (Cr 3 , In 3 , Al 3 , Cu 2 and Zn 2 ) were prepared by the hydro-and solvo-thermal methods and characterized by XRD, N2 adsorptiondesorption isotherm, TG-DTA and FE-SEM. The prepared MOFs were crystalline and phase-pure. MOFs were used as column packings for chromatographic separation of alkylbenzenes. MOFs recognized differences in molecular sizes in addition to boiling points of alkylbenzenes. Activation energy for diffusion in the MOF micropores ranged from 25 to 60 kJ mol -1. Temperature-programmed XRD measurement in air revealed that no expansion or contraction of MOF frameworks occurred up to 230 .
The slurry utilized in prime wafer polishing in semiconductor manufacturing is well known to contain abrasive grains of SiO2. The pH value of this slurry is in the range from 9 to 11.On the behavior of metallic contamination, the following experimental results are obtained from our works. Iminodiacetate fiber was found to remove copper over 90% from the slurry used in CMP(Chemical Mechanical Polishing) process. The removal rate of the copper was also found to decrease with increasing in time after slurry was contaminated by metallic impurities. It is cited that this phenomenon is caused by the adhesion and diffusion of copper onto abrasive grains of SiO2 in slurry from Solid Phase Extraction (SPE) Analysis.
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