• Korean Chemical Engineering Research
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• v.51 no.3
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• pp.347-351
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• 2013

The preparation of glycerol carbonate (GC) from urea through carbonylation with renewable glycerol was investigated by using ionic liquid catalysts. It was found that quaternary ammonium salt and imidazolium salt ionic liquids with a shorter alkyl chain length and higher nucleophilic anion showed better catalytic performance. The effects of reaction temperature, reaction time and degree of vacuum on the reactivity of TBAC catalyst ware discussed. Zinc chloride ($ZnCl_2$) was used as co-catalyst with the ionic liquid catalyst. The mixed catalyst showed a synergy effect on the glycerol conversion and GC yield probably due to the acid-base properties of the catalysts.

• Journal of the Korean Electrochemical Society
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• v.17 no.1
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• pp.65-70
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• 2014

In this study, crosslinked poly(POEM-co-AMPSLi-co-GMA)s were prepared by epoxy coupling of GMA after radical copolymerization of AMPS, POEM and GMA followed by acid-base titration reaction between sulfonic acid of AMPS and $Li_2CO_3$. It was observed that the crystalline melting temperature of POEM was effected by mol% of components and shifted to lower value by lithiation of AMPS group. The ionic conductivity of crosslinked polymer electrolyte was decreased by addition of GMA but maintained over $1.0{\times}10^{-6}S\;cm^{-1}$ until 16 mol%. Particularly, the self-doped polymer electrolyte with 2 mol% of GMA showed its ionic conductivity as high as $4.08{\times}10^{-6}S\;cm^{-1}$ at room temperature and electrochemical stability up to 6 V. In addition, 0.11 MPa of modulus and 270% of elongation were obtained from the free standing film of crosslinked polymer electrolyte.

• Analytical Science and Technology
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• v.7 no.2
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• pp.173-179
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• 1994

The point of present study was focused on developing the method for the determination of dissociation constant by means of FIA conjunction with Diode Array Spectrphotometry or spectrophotometry along with small amount of Bromocresol Green(mg order) within short time. On the calculation with computer, the indicator with pK=7 has been shown the most sensitive reaction when little amount of base or acid has been added. The pKa of Bromothymol Blue and Bromocresol Green were measured as 7.31 and 4.82 respectively with spectrophotometry after activity correction by Kielland method (Reported value by Bishop, 7.30 and 4.79). The pKa of Bromocresol Green by FIA was obtained as 4.78 and was comparable with other values determined by other methods.

• Journal of Microbiology and Biotechnology
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• v.14 no.2
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• pp.417-421
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• 2004

A normal prion protein (PrPc) is converted to a protease resistant isoform (PrPsc) by an apparent self-propagating activity in bovine spongiform encephalopathies (BSE), which is a neurodegenerative disease. The cDNA encoding bovine PrP open reading frame (ORP) in Korean cattle was cloned by polymerase chain reaction (PCR). The cloned cDNA had a length of 795 base pairs which coded for a protein of 264 amino acid residues with a calculated molecular mass of 28.6 kDa. Identities of 90, 90, 79 and 78% on nucleotide and 94, 94, 84, and 84% on amino acid sequence were shown to PrP genes from sheep, goat, human, and mouse, respectively. The cloned DNA was ligated into the pQE30 expression vector and transformed into E. coli M15. The PrP was expressed by induction with isopropyl-$\beta$-D-thiogalactoside (IPTG) and purified on the Ni-NTA affinity column. High specific activities of the recombinant PrP were observed in the fraction of pH 5.8 eluate and showed a molecular mass of-29 kDa on SDS-PAGE and Western blot analysis.

• The Journal of Korean Society of Virology
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• v.28 no.3
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• pp.215-224
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• 1998

Cloning, sequencing and expressing in E. coli of the thymidine kinase (TK) gene of Herpes simplex virus type-1 (HSV-1) strain F was investigated. The TK gene, located in the BamHI 3.74 kb DNA fragment of the plasmid pHLA-12, was amplified by polymerase chain reaction (PCR). The 1,131 kb PCR product was cloned into the BamHI and EcoRI sites of pBacPAK9 plasmid and then named pBac-TK recombinant. The TK gene was subcloned into the BamHI and BglII sites of pQE-30, and named pQE-TK recombinant. The nucleotide sequence of the 1,131 kb TK gene was determined, and the GC content was 65.13%. There were deduced 367 amino acid residues with a total molecular weight of 43 kDa. The weight was confirmed by the protein produced by E. coli M15/pQE-TK on the SDS-PAGE and Western blot. The production of the TK protein in the IPTG induced cells was measured over 4 h. At the end of 1, 2 and 3 h the level increased by 146, 204 and 242%, respectively. The amount of the protein at the highest fraction purified with Ni-NTA resin chromatography was $0.68\;{\mu}g$ per ml. The soluble state TK protein was present in the cytoplasm. In these results the F strain was different in base sequence and amino acid sequence from that of the CL101 strain, which caused difference in their strains.

• Environmental Analysis Health and Toxicology
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• v.26
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• pp.5.1-5.11
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• 2011

Objectives: In order to identify the possibility of slender bitterling (SB) (Acheilognathus yamatsutae) being used as a test species for estrogenic endocrine disrupting chemicals (EEDCs), we carried out the cloning and sequence characterization of the estrogen receptor (ER). Methods: The ER from a slender bitterling was obtained by reverse transcriptase-polymerase chain reaction (RT-PCR), 5'- and 3'-rapid amplification of cDNA ends (5'-RACE and 3'-RACE) and T-vector cloning. The expression of ER mRNA was also analyzed in six tissues (brain, liver, kidney, gill, gonad, and intestines) by real-time PCR. Results: We obtained an ER from the slender bitterling. The SB ER cDNA was 2189 base pairs (bp) in length and contained a 1707 bp open reading frame that encoded 568 amino acid residues. The SB ER amino acid sequence clustered in a monophyletic group with the $ER{\alpha}$ of other fish, and was more closely related to zebrafish $ER{\alpha}$(88% identity) than to the $ER{\alpha}$ of other fish. The SB ER cDNA was divided into A/B, C, D, E and F domains. The SB ER has conserved important sequences for ER functions, such as the DNA binding domain (D domain), which are consistent with those of other teleosts. Conclusions: The ER of the slender bitterling could provide basic information in toxicological studies of EEDCs in the slender bitterling.

• The Korean Journal of Pesticide Science
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• v.2 no.1
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• pp.46-52
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• 1998

The hydrolysis rate of insecticidal buprofezin(IUPAC : tert-butylimino-3-isopropyl-5-phenylperhydro-1,3,5-thiadiazin-4-one) in the range of pH 2.0 and 12.0 have been examined in 15%(v/v) aqueous dioxane at $45^{\circ}C$. The hydrolysis mechanism of buprofezin is proposed from the pH-effect, solvent effect(${\ell}{\gg}m$), thermodynamic parameter(${\Delta}H^{\neq}$=11.12 $Kcal{\cdot}mol^{-1}$ &, ${\Delta}S^{\neq}=5.0e.u.$), rate equation and hydrolysis product, l-isopropyl-3-phenyl urea. General acid catalyzed hydrolysis and specific acid catalyzed($k_{H3O+}$) hydrolysis through $A-S_{E}2$ and A-2(or $A_{AC}2$) reaction mechanism with orbital-control reaction proceed below pH 8.0 and above pH 9.0, the nucleophilic addition-elimination, $Ad_{N}-E$ mechanism via tetrahedral($sp^{3}$) intermediate is initiation by general base catalyzed($k_{H2O}$) reaction. Buprofezin was more stable in alkaline ($k=10^{-8}sec.^{-1}$) than acid solutions from the sigmoid pH-rate profile. And the half-life($t=\frac{1}{2}$) of hydrolysis reaction in neutral aqueous solution(pH 7.0) at $45^{\circ}C$ was about 3 months.

• Korean Chemical Engineering Research
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• v.43 no.6
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• pp.756-760
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• 2005

In this study, the effect of $N_2$-plasma treatment on carbon blacks (CBs) was investigated by analyzing acid-base surface values and surface functional groups of CBs. The surface characteristics of the CBs were determined by fourier transformed-infrared (FT-IR) spectrometer, X-ray photoelectron spectroscopy (XPS), and Boehm's titration method. Electrochemical properties of the plasma-treated CBs-supported Pt (Pt/CBs) catalysts were analyzed by cyclic voltammetry (CV) experiments. From the results of FT-IR and acid-base values, $N_2$-plasma treatment at 300 W intensity on the CBs led to the formation of the free radical. The peak intensity was increased with increasing the treatment time due to the formation of new basic functional groups(such as C-N, C=N, $-NH_3{^+}$, -NH, and =NH) by the free radical. Accordingly, the basic values were increased by the basic functional groups. However, after a specific reaction time, $N_2$-plasma treatment could hardly influence change of surface functional groups of CBs, due to the disappearance of free radical. Consequently, it was found that optimal treatment time was 30 second for electro activity of Pt/CBs catalysts.

• Journal of Life Science
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• v.23 no.12
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• pp.1557-1561
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• 2013

Carbonic anhydrase isozymes are a widespread, zinc-containing metalloenzyme family. The enzyme catalyzes the reversible inter-conversion of $CO_2$ and $HCO_3$. This reaction is the main role played by CA enzymes in physiological conditions. This enzyme has been found in virtually all organisms, and at least 16 isozymes have been isolated in mammals. Unlike mammals, there is little information available regarding CA isozymes in the tissues of non-mammalian groups, such as fish. Carbonic anhydrase is very important in the osmotic and acid-base regulation in fish. It is well-known that the gills of fish play the most important role in acid-base relevant ion transfer, the transfer of $H^+$ and/or $HCO_3^-$, for the maintenance of systemic pH. Rainbow trout, Oncorhynchus mykiss, is the most important freshwater fish species in the aquaculture industry of Korea, with annual production increasing each year. In addition, environmental toxicology research has shown that rainbow trout is known to be the species that is most susceptible to environmental toxins. Consequently, carbonic anhydrase was detected in rainbow trout, Oncorhynchus mykiss. The isolated protein showed the specific band with a molecular weight of 30 kDa and pI of 7.0, and it was identified as being carbonic anhydrase. The immunohistochemical result demonstrated that the carbonic anhydrase was located in the epithelial cells of the gills.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.10
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• pp.957-964
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• 2010

The deactivated catalyzed diesel particulate filter-trap (DPF) was remanufactured by ultrasonic wave treatment with various prepared solutions, followed by active component re-impregnation, and the emission control performance and surface properties of remanufactured DPF were studied at various remanufacturing conditions. The proper ultrasonic wave cleaning time at various prepared solutions and optimal re-impregnation amounts of active component for the best emission control performance of DPF were investigated and its performance tests were also carried out with various temperatures for the conversions of CO, THC (total hydrocarbon) and PM (particulate matter) by catalytic reaction test unit using bypass gas from the diesel engine dynamo system. It was found that the emission control performance of DPF remanufactured with the high-temperature air washing, ultrasonic wave cleaning at acid/base solutions and active component re-impregnation method was recovered to 95% level of its activity compared to that of the fresh DPF, which was caused by removing the deactivating materials from the surface of the DPF, through the analyses of performance test and their surface characterization by Optical microscope, EDX, ICP, TGA, and porosimeter.