• KEPCO Journal on Electric Power and Energy
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• 제8권1호
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• pp.37-41
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• 2022

Because sulfur hexafluoride(SF₆) is classified as one of the six major greenhouse gases, SF₆ handling in power plant such as recovery, purification, and reuse is considered to be important. KEPCO has focused to develop the advanced recovery and purification technology of SF₆ reuse. SF₆ analysis includes the on-site analyses and on-line analyzer; i.e., (1) on-site analysis has an error rate of ±0.5% and (2) on-line analysis has an error rate of ±0.1%, which is possible to adjust operating conditions and to make the work more conveniently by analyzing SF₆ concentration before and after purification step. This paper presents an online analysis method in the SF₆ purification and reuse system. In addition, the analysis results and quality guarantees for each section of the analysis system were presented.

• KEPCO Journal on Electric Power and Energy
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• 제6권1호
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• pp.53-58
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• 2020

Korea Electric Power Corporation (KEPCO) uses large amount of SF₆, one of the potent greenhouse gases, in electric equipment for electrical insulation. KEPCO is developing SF₆ recovery and purification technology to minimize the release of SF₆ into the environment, to secure certified emission reduction, and to save purchase cost of new SF₆ by reusing the refined SF₆. A prototype SF₆ purification system using cryogenic solidification technology has been built in demonstration scale. To evaluate the feasibility of the commercialization, the system has been operated to purify large amount of used SF₆ in a long-term operation and the performance has been economically evaluated. The system was stable enough for commercial operation such that it was able to purify 5.4 tons of used SF₆ from power transmission equipment in 2-month operation. Over 99% of the SF₆ was recovered from the used gas and the purity of the purified gas was over 99.7 vol%. The operation cost, which is the cost of refrigerant (liquid nitrogen), electricity and labor, per kilogram of purified SF₆ was 6,526 KRW. Considering the price of new SF₆ in Korea is about 15,000 KRW per kilogram this year, about 56% of the purchase cost can be saved.

• BMB Reports
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• 제31권6호
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• pp.585-589
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• 1998

The herpes simplex virus type-1 (HSV-1)-encoded DNA polymerase consists of two subunits, the products of the UL30 and UL42 genes. UL30 and UL42 were coexpressed in Sf9 cells infected with recombinant baculoviruses carrying the two genes. The UL30 and UL42 gene products remained tightly associated throughout the purification, which led to a near homogeneous heterodimer composed of the DNA polymerase and UL42 protein. The DNA polymerase-UL42 protein heterodimer, purified from the recombinant baculovirus-infected Sf9 cells, showed the same high degree of processivity of deoxynucleotide polymerization as the enzyme purified from the HSV-1 infected primate cells. Like the latter, it contained a 3'-5' exonuclease activity that specifically hydrolyzes an incorrectly matched nucleotide at the 3' terminus of a primer, thereby contributing to the fidelity of DNA replication.

• 한국지하수토양환경학회지:지하수토양환경
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• 제28권6호
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• pp.33-44
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• 2023

A risk assessment on the heavy metals including arsenic (As), cupper (Cu), lead (Pb), and zinc (Zn) was investigated by setting exposure routes in agricultural fields. Moreover, the factors requiring improvement in risk assessment were also discussed through a review of the dermal absorption slope factor (SF_abs) and total amount of suspended particles (TSP) in the current risk assessment guidelines. Assessment results show that the total cancer risk (TCR) of As through crop and soil ingestion was 1.51E-03 in adults and 6.37E-4 in children, which indicated a carcinogenic risk (exceeding 1E-05). On the other side, the harzard index (HI) was 3.37 in adults and 1.41 in children, which was evaluated as having a non-carcinogenic risk (>1). The carcinogenic purification targets for As were calculated to be 6.84 mg/kg in adults and 6.86 mg/kg in children, while the non-carcinogenic purification targets were calculated to be 13.43 mg/kg for adults and 22.54 mg/kg for children. When applying SF_abs 61 of the current guidelines, it appears that there is a carcinogenic risk even though the As exposure concentration is below the area of concern 1 standard (25 mg/kg), which suggestes that additional research on this factor is required for the risk assessment. In order to apply the measured suspended particle concentration to risk assessment, TSP should be derived from PM10 using an appropriate correlation equation. As a result, it is suggested to improve the risk assessment guidelines so that the mesured PM10 value measured in the field can be used directly.

• 한국약용작물학회지
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• 제12권2호
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• pp.135-140
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• 2004

Total RNAs were isolated from cultured roots of Scopolia parviflora, $poly(A)^+$ RNA was obtained through the mRNA purification, cDNA library of Hnh6h was constructed. Recombinant baculoviruses in Spodoptera frugiperda (Sf) cells were constructed by use of the transfer vector pBacPAK, which has the AcNPV sequence under the polyhedrin promoter. The expression vector carrying Hnh6h gene was transferred to S. parviflora and obtained transgenic hairy root lines. Our results confirmed the over expression of the H6H protein was used by anti-pBacPAK about cDNAs of S. parviflora. This study will served for production of tropane alkaloids by metabolic engineering.

• Journal of Microbiology and Biotechnology
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• 제29권9호
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• pp.1470-1477
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• 2019

${\beta}_2$-adrenergic receptor (${\beta}_2-AR$) was expressed efficiently using Bac-to-Bac Baculovirus Expression System in Sf9 cells as a bio-recognition element for multianalyte screening of ${\beta}$-agonist residues in pork. Sf9 cells were selected as the expression system, and codon optimization of wild-type nucleic acid sequence and time-dependent screening of expression conditions were then carried out for enhancing expression level and biological activity. Under optimum conditions of multiplicity of infection (MOI) = 5 and 48 h post transfection, the protein yield was up to 1.23 mg/ml. After purification by chromatographic techniques, the purified recombinant protein was applied to develop a direct competitive enzyme-linked receptor assay (ELRA) and the efficiency and reliability of the assay was determined. The IC50 values of clenbuterol, salbutamol, and ractopamine were 28.36, 50.70, and $59.57{\mu}g/l$, and clenbuterol showed 47.61% and 55.94% cross-reactivities with ractopamine and salbutamol, respectively. The limit of detection (LOD) was $3.2{\mu}g/l$ and the relevant recoveries in pork samples were in the range of 73.0-91.2%, 69.4-84.6%, and 63.7-80.2%, respectively. The results showed that it had better performance compared with other present nonradioactive receptorbased assays, indicating that the genetically modified ${\beta}_2-AR$ would have great application potential in detection of ${\beta}$-agonist residues.

• Journal of Microbiology and Biotechnology
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• 제23권4호
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• pp.499-510
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• 2013

Among 25 isolates, Aspergillus fumigatus ASH (JX006238) was identified as a potent producer of homocysteine ${\gamma}$-lyase. The nutritional requirements to maximize the enzyme yield were optimized under submerged (SF) and solid-state fermentation (SSF) conditions, resulting in a 5.2- and 2.3-fold increase, respectively, after the last purification step. The enzyme exhibited a single homogenous band of 50 kDa on SDS-PAGE, along with an optimum pH of 7.8 and pH stability range of 6.5 to 7.8. It also showed a pI of 5.0, as detected by pH precipitation with no glycosyl residues. The highest enzyme activity was obtained at $37-40^{\circ}C$, with a $T_m$ value of $70.1^{\circ}C$. The enzyme showed clear catalytic and thermal stability below $40^{\circ}C$, with $T_{1/2}$ values of 18.1, 9.9, 5.9, 3.3, and 1.9 h at $30^{\circ}C$, $35^{\circ}C$, $40^{\circ}C$, $50^{\circ}C$, and $60^{\circ}C$, respectively. Additionally, the enzyme $K_r$ values were 0.002, 0.054, 0.097, 0.184, and 0.341 $S^{-1}$ at $30^{\circ}C$, $35^{\circ}C$, $40^{\circ}C$, $50^{\circ}C$, and $60^{\circ}C$, respectively. The enzyme displayed a strong affinity to homocysteine, followed by methionine and cysteine when compared with non-S amino acids, confirming its potency against homocysteinuria-related diseases, and as an anti-cardiovascular agent and a specific biosensor for homocysteinuria. The enzyme showed its maximum affinity for homocysteine ($K_m$ 2.46 mM, $K_{cat}\;1.39{\times}10^{-3}\;s^{-1}$), methionine ($K_m$ 4.1 mM, $K_{cat}\;0.97{\times}10^{-3}\;s^{-1}$), and cysteine ($K_m$ 4.9 m M, $K_{cat}\;0.77{\times}10^{-3}\;s^{-1}$). The enzyme was also strongly inhibited by hydroxylamine and DDT, confirming its pyridoxal 5'-phosphate (PLP) identity, yet not inhibited by EDTA. In vivo, using Swiss Albino mice, the enzyme showed no detectable negative effects on platelet aggregation, the RBC number, aspartate aminotransferase, alanine aminotransferase, or creatinine titer when compared with negative controls.