• KSBB Journal
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• v.21 no.4
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• pp.298-301
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• 2006

A gene(GeneBank AF 135796) coding for a trehalose synthase from Thermus caldophilus GK24 was cloned into Escherichia coli K12 using five vector systems. The constitutive expression system(pHCETS) which shows the highest trehalose synthase activity from flask culture of recombinant E. coli was selected for the production of trehalose from maltose. For the shake flask culture, the final dry cell weight was 0.9 g/L and the trehalose synthase activity was 25 U/mL. Fed-batch culture of recombinant E. coli harboring plasmid pHCETS which uses the glycerolas a carbon source was performed in jar fermentor: the dry cell weight of 20 g/L and the trehalose synthase activity of 13.7 U/mL were attained in 48 h.

• Polymer(Korea)
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• v.24 no.1
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• pp.16-22
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• 2000

Poly(butylene terephthalate- co-oxybenzoate)(PBOT) containing mesogenic oxybenzoate units in the main chain was synthesized through ester exchange reaction by melt mixing of poly(butylene terephthalate)(PBT) and p-acetoxybenzoic acid (ABA). From the kinetics of the copolymerization reaction, the activation energies and the rate constants of homopolymerization and copolymerization, k$_{h}$ and k$_{c}$, could be determined. From the reaction conditions of different compositions, 4/6, 5/5, and 6/4 of PBT/ABA, at 250, 260, and 27$0^{\circ}C$, it was revealed that copolymerization between PBT and ABA proceeds on a pseudo-second order reaction if the ABA content and its conversion are low. In this case, the ratio of rate constants of homopolymerization to copolymerization was in the range from 1.08 to 3.17, indicating that the copolymer with more notable block character was obtained at the higher mole fraction of ABA and at higher temperature.e.e.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.32 no.4 s.59
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• pp.263-267
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• 2006

Antioxidative and anti-inflammatory activities of Petasites japonicus extract were evaluated. P. japonicus extract showed 70.1% inhibition on peroxidation of linoleic acid. In the experiment using the cell permeable dye, 2',7'- dichlorofluorescein diacetate (DCFDA) as an indicator of reactive oxygen species (ROS) generation, intracellular oxidative stress in UVB-irradiated keratinocytes was shown to be decreased by P. japonicus extract. Also, UVB-induced production of interleukin-$1{\alpha}$ and prostaglandin $E_2$ in human HaCaT keratinocytes was reduced in a dose-dependent manner by treatment with P. japonicus extract. All these results suggest that P. japonicus extract can be effectively used for prevention of UV-induced adverse skin reactions such as radical production and inflammation.

• Reproductive and Developmental Biology
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• v.31 no.3
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• pp.161-167
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• 2007

In this study, we constructed and tested retrovirus vectors designed to express the human thrombopoietin gene under the control of the tetracycline-inducible promoters. To increase the hTPO gene expression at him-on state, WPRE sequence was also introduced into retrovirus vector at downstream region of either the hTPO gene or the sequence encoding reverse tetracycline-controlled transactivator (rtTA). Primary culture cells (PFF, porcine fetal fibroblast; CEF, chicken embryonic fibroblast) infected with the recombinant retrovirus were cultured in the medium supplemented with or without doxycycline for 48hr, and induction efficiency was measured by comparing the hTPO gene expression level using RT-PCR, western blot and ELISA. Higher hPTO expression and tighter expression control were observed from the vector in which the WPRE sequence was placed at downstream of the hTPO (in CEF) or rtTA(in PFF) gene. This resulting tetracycline inducible vector system may be helpful in solving serious physiological disturbance problems which have been a major obstacle in successful production of transgenic animals.

• Korean Chemical Engineering Research
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• v.50 no.3
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• pp.391-397
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• 2012

The depletion of conventional oil reserves and the increasing energy need in developing countries such as China and India result in exceeding oil demand over supply. As a solution of the problem, the efficient utilization of heavy oil has been receiving more and more interest. In order to utilize heavy oil, upgrading processes are required. Among the upgrading processes, thermal decomposition is thought to be relatively simple and economical. In this study, to understand basic characteristics of thermal decomposition of heavy oil, we conducted pyrolysis experiments of deasphalted oil (DAO) produced by a solvent deasphalting process. DAO is a mixture of many components and consists mainly of materials of carbon number 20~40. For the comparison with results of DAO pyrolysis, additional pyrolysis experiments with single materials of carbon number 30 ($C_{30}H_{62}$, $C_{30}H_{58}O_4S$, $C_{30}H_{63}O_3P$) were conducted. Pyrolysis experiments were carried out non-isothermally with variation of heating rate (10, 50, $100^{\circ}C$/min) in a thermogravimetric analyzer. Average pyrolysis activation energy determined by using Arrhenius method, Ingraham and Marrier method, and Coats and Redfern method was 72~99 kJ/mol. In the activation energy calculated by Ozawa-Flynn-Wall method, DAO had wider variation than other single materials.

• Food Science and Preservation
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• v.23 no.1
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• pp.49-56
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• 2016

This study analyzed the physicochemical characteristics of Astragalus membranaceus (AM) fermented with seven different mushroom mycelia. Physicochemical characteristics, such as contents of moisture, pH, total reducing sugars, free sugar, and isoflavonoid, were investigated. The moisture content was increased in most of the samples. The pH values of AM fermented with Phellinus linteus and Flammulina velutipes were increased, while the pH of other samples were similar to that of non-fermented AM. The reducing sugar content was in the range of 211.69~391.74 mg/100 g. The extraction yield using water was higher than that when extracted with 80% ethanol. The free sugar content was increased through fermentation with mushroom mycelia. However, the glucose contents of the 80% ethanol and water extracts were decreased. Finally, the calycosin and formononetin contents in 80% ethanol and water extracts of AM fermented with Phellinus linteus were 2,549.24 mg/g, and 827.66 mg/g for calycosin, and 1,366.69 mg/g and 221.28 mg/g for formononetin, respectively. These results suggest that fermentation with mushroom mycelia could be used to increase the bioactivity of AM. The mycelium-fermented AM might be a valuable source of functional material and edible resource for industry.

• Journal of The Korean Society of Grassland and Forage Science
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• v.24 no.4
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• pp.335-340
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• 2004

This experiment was conducted to compare the dry matter yields and feed values of summer forage crops such as two cultivars of Maize, two cultivars of Sorghum hybrid and one Japanese millet at the Dae-Ho reclaimed tideland, Korea from 2002 to 2003. Seasonal changes of soil salt content maintained somewhat low at early stage and increased at growing stage and then decreased at harvest time. The dry matter yield was 6,102, 4,557 and 2,928 kg/ha, respectively, for Japanese millet Sorghum hybrid and Maize. The highest Crude protein(CP) content was recorded in sorghum hybrid. Neutral detergent fiber.(NDF) and acid detergent fiber(ADF) contents were highest in Japanese millet following Sorghum hybrid and Maize in turn. The highest sodium content in plant tissue was recorded in Japanese millet. These results suggest that Japanese millet is the most suitable summer forage crops for cultivation on reclaimed tideland in view of the good emergence and forage production.

• Journal of Embryo Transfer
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• v.33 no.3
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• pp.129-137
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• 2018

Acute vascular rejection has been known as a main barrier occurring in a xenograted tissue of alpha 1,3-galactosyltransferase knock-out (GalT KO) pig into a non-human primate (NHP). Adenosine which is a final metabolite following sequential hydrolysis of nucleotide by ecto-nucleotidases such as CD39 and CD73, act as a regulator of coagulation, and inflammation. Thus xenotransplantation of CD39 and CD73 expressing pig under the GalT KO background could lead to enhanced survival of recipient NHP. We constructed a human CD39 and CD73 expression cassette designed for endothelial cell-specific expression using porcine Icam2 promoter (pIcam2-hCD39/hCD73). We performed isolation of endothelial cells (pAEC) from aorta of 4 week-old GalT KO and membrane cofactor protein expressing pig ($GalT^{-MCP/-MCP}$). We were able to verify that isolated cells were endothelial-like cells using immunofluorescence staining analysis with von Willebrand factor antibody, which is well known as an endothelial maker, and tubal formation assay. To find optimal condition for efficient transfection into pAEC, we performed transfection with GFP expression vector using four programs of nucleofection, M-003, U-023, W-023 and Y-022. We were able find that the program W-023 was optimal for pAEC with regard to viability and transfection efficiency by flow cytometry and fluorescent microscopy analyses. Finally, we were able to obtain $GalT^{-MCP/-MCP}/CD39/CD73$ pAEC expressing CD39 and CD73 at levels of 33.3% and 26.8%, respectively. We suggested that pACE isolated from $GalT^{-MCP/-MCP}$ pig might be provided as a basic resource to understand biochemical and molecular mechanisms of the rejections and as an alternative donor cells to generate $GalT^{-MCP/-MCP}/CD39/CD73$ pig expressing CD39 and CD73 at endothelial cells.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.1
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• pp.1-8
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• 2010

To investigate the effects of sediments on the water quality of an estuary reservoir, Asan reservoir, we analyzed physical and chemical characteristics of the sediments and estimated nutrients release rate from the sediments. The sediments characterized as sandy loam are mainly composed of Nonapatite-P(64.7%) which has strong influence on the eutrophication of the reservoir by releasing from the sediments under the condition of increasing pH and anaerobic environment. High nutrient release rates was observed in April. Negative release rates in June show that there is no significant nutrient release from the sediments. The nutrient release was active at the Site B around the confluence of tributary compared to the Site A near the embankment. Based on the information of nutrient release rates and sediments surface area, daily average nutrient release rates of Asan reservoir are estimated; TN 6,609 kg/d, TP 3,877 kg/d. Since the amount of N and P released from the sediments corresponds to the 7.06% of N and 22.04% of P incoming from the watershed, it can be concluded that there is little influence of sediments on the water quality of Asan reservoir.

• Journal of Plant Biotechnology
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• v.41 no.4
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• pp.194-200
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• 2014

Monodehydroascorbate reductase (MDHAR) is an important enzyme that plays a role in the detoxification of reactive oxygen species (ROS) by maintaining reduced pool of ascorbate through recycling the oxidized form of ascorbate. In this study, we isolated a PagMDHAR1 gene from Populus alba ${\times}$ P. glandulosa, and investigated its expression characteristics. The PagMDHAR1 cDNA encodes a putative 434 amino acids containing FAD- and NAD(P)H-binding domains. Southern blot analysis indicated that a single nuclear gene encodes this enzyme. Northern hybridization analysis revealed that PagMDHAR1 is highly expressed in both suspension cells and flower tissues, while its expression levels were enhanced by drought, salt, cold, wounding and ABA. Therefore, PagMDHAR1 might be expressed in response to abiotic stress through the ABA-mediated signaling pathway in this poplar species, suggesting that the PagMDHAR1 plays an important role in the defense mechanisms against oxidative stress.