• Food Science and Biotechnology
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• v.14 no.3
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• pp.317-322
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• 2005

A simple and convenient method of immobilizing dextransucrase via an affinity interaction is described, along with the use of this system to synthesize leucrose. Dextransucrase was produced in sucrose-free medium by fermenting a constitutive mutant of Leuconostoc mesenteroides NRRL B-512F and was separated using an ultrafiltration membrane. The purified enzyme was free of dextran polymer, which previously was always found with the sucrose-induced enzyme. Therefore, it was possible to immobilize the enzyme on dextran-based resins using an affinity interaction. Sephadex G-200 was the best resin for immobilizing the dextransucrase and gave a fast flow rate through the packed column. The immobilized dextransucrase retained more than 80% of its specific activity after immobilization ($K_m\;=\;18.1\;mM$ and $k_{cat}\;=\;450\;sec^{-1}$ vs. 13.1 mM and $640\;sec^{-1}$, respectively, for the free enzyme). The immobilized dextransucrase showed improved stability over a pH range of 4.0 to 6.5 and at moderately high temperatures over $40^{\circ}C$. When immobilized dextransucrase was used to synthesize leucrose via the transfer reaction with sucrose and fructose, about 74% of the sucrose was converted into leucrose after one day, and the half-life of the enzyme activity was 15 days. Regeneration of the resin by supplementation with dextransucrase enabled the recovery of the initial activity of the system, but both the reaction and the flow rate were lower, probably owing to the accumulation of dextran inside the resin.

• Journal of the Korean Society for Library and Information Science
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• v.35 no.4
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• pp.161-175
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• 2001

The purpose of this study is to examine how the titles and corporate names of Japanese scholarly journals are treated, and how well the authority control is implemented to assist the access with various names and forms of names to the OPACS. Without the help of either references or internal links among those names and forms of names in the DBs, users are likely to fail in getting the right results. In this study, the cataloging records for serials from the National Assembly Library, KISTI, Yonsei University and the KERIS were examined, and the comparison was made with the records from the NACIS-WebCat of the National Institute of Informatics in Japan. Major findings include (1) the lack of consistency in applying cataloging rules, (2) the lack of proper authority control in treating corporate names, and (3) the lack of references or links among names and variant forms of names. The overall improvement of cataloging practices and application of authority control is strongly recommended for enabling users to access better to those DBs of interest.

• Parasites, Hosts and Diseases
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• v.30 no.1
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• pp.1-14
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• 1992

In order to observe the antigenic localization in the tissues of Paragonimus westermani of deve- lopmental stages, immunogoldlabeling method was applied using serum of the cats which were infected with isolated metacercariae from Cambaroides similis. The sectioned worm tissues from orch developmental stage were embedded in Lowicryl HM20 medium, stained with infected semi IgG and protein A gold complex(particle size: 12 nm) and observed by electron microscopy. In the young adult worm tissue of 4 weeks after infection with metacercariae, the gold particles were specifically concentrated on the tegumental syncytium and cytoplasm of the tegumental cells as well as the secretory granules in the parenchymal tissue. The antigenic materials in the adult worm tissue were specifically concentrated on the secretory granules in the parenchymal tissue, the cytoplasm between granules in the vitelline gland and the epithelial lamella in the lumen of the caecum.

• Journal of Microbiology and Biotechnology
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• v.15 no.3
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• pp.587-594
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• 2005

The contribution of electrostriction of water molecules to the stabilization of the negatively charged tetrahedral transition state of a lipase-catalyzed reaction was examined by means of kinetic studies involving high-pressure and solvent dielectric constant. A good correlation was observed between the increased catalytic efficiency of lipase and the decreased solvent dielectric constant. When the dielectric constant of solvents was lowered by 5.00 units, the losses of activation energy and free energy of activation were 7.92 kJ/mol and 11.24 kJ/mol, respectively. The activation volume for $k_{cat}$ decreased significantly as the dielectric constant of solvent decreased, indicating that the degree of electrostriction of water molecules around the charged tetrahedral transition state has been enhanced. These observations demonstrate that the increase in the catalytic efficiency of the lipase reaction with decreasing dielectric constant resulted from the stabilization of electrostatic energy for the formation of an oxyanion hole, and that this stabilization was caused by the increase of electrostricted water around the charged tetrahedral transition state. Therefore, we conclude that the control of solvent dielectric constant can stabilize the tetrahedral transition state, thus lowering the activation energy.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.110.1-110.1
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• 2010

A bench scale slurry bubble column reactor (SBCR) with active-Fe based catalyst was developed for the Fischer-Tropsch synthesis (FTS) reaction. Considering the highly exothermic reaction heat generated in the bench scale SBCR, an effective cooling system was devised consisting of a U-type dip tube submerged in the reactor. Also, the physical and chemical properties of the catalyst were controlled so as to achieve high activity for the CO conversion and liquid oil ($C_{5+}$) production. Firstly, the FTS performance of the FeCuK/$SiO_2$ catalyst in the SBCR under reaction conditions of $265^{\circ}C$, 2.5 MPa, and $H_2/CO=1$ was investigated. The CO conversion and liquid oil ($C_{5+}$) productivity in the reaction were 88.6% and 0.226 $g/g_{cat}-h$, respectively, corresponding to a liquid oil ($C_{5+}$) production rate of 0.03 bbl/day. To investigate the FTS reaction behavior in the bench scale SBCR, the effects of the space velocity and superficial velocity of the synthesis gas and reaction temperature were also studied. The liquid oil production rate increased upto 0.057 bbl/day with increasing space velocity from 2.61 to 3.92 $SL/h-g_{Fe}$ and it was confirmed that the SBCR bench system developed in this research precisely simulated the FTS reaction behavior reported in the small scale slurry reactor.

• Journal of Microbiology and Biotechnology
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• v.28 no.9
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• pp.1482-1492
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• 2018

Fusarium oxysporum trypsin (FOT) is a fungal serine protease similar to mammal trypsin. The FOT could be successfully expressed in Pichiapastoris by engineering the natural propeptide APQEIPN. In this study, we constructed two recombinant enzymes with engineered amino acid sequences added to the N-terminus of FOT and expressed in P. pastoris. The N-terminal residues had various effects on the structural and functional properties of trypsin. The FOT, and the recombinants TE (with peptide YVEF) and TS (with peptide YV) displayed the same optimum temperature ($40^{\circ}C$) and pH (8.0). However, the combinants TE and TS showed significantly increased thermal stability at $40^{\circ}C$ and $50^{\circ}C$. Moreover, the combinants TE and TS also showed enhanced tolerance of alkaline pH conditions. Compared with those of wild-type FOT, the intramolecular hydrogen bonds and the cation ${\pi}$-interactions of the recombinants TE and TS were significantly increased. The recombinants TE and TS also had significantly increased catalytic efficiencies (referring to the specificity constant, $k_{cat}/K_m$), 1.75-fold and 1.23-fold than wild-type FOT. In silico modeling analysis uncovered that the introduction of the peptides YVEF and YV resulted in shorter distances between the substrate binding pocket (D174, G198, and G208) and catalytic triad (His42, Asp102, and Ser180), which would improve the electron transfer rate and catalytic efficiency. In addition, N-terminal residues modification described here may be a useful approach for improving the catalytic efficiencies and characteristics of other target enzymes.

• Journal of Hydrogen and New Energy
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• v.22 no.2
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• pp.249-256
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• 2011

In this study, the Ni-based catalysts for the production of synthetic natural gas were prepared by various preparation methods such as the co-precipitation, precipitation, impregnation and physical mixing methods. The ranges of the reaction conditions were the temperatures of 250~$350^{\circ}C$, $H_2$/CO mole ratio of 3.0, the pressures of 1 atm and the space velocity of 20000 $ml/g_{-cat{\cdot}}{\cdot}h$. It was found that the catalyst prepared by precipitation method had higher CO conversion than the catalyst prepared by co-precipitation method. While the catalyst prepared by precipitation method had the formation of NiO structure, the catalyst prepared by co-precipitation method had the formation of $NiAl_2O_4$ structure. It was confirmed that Ni-based catalyst prepared by the physical mixing method had the lowest CO conversion because it was deactivated by the production of $Ni_3C$ during the methanation. As a result, it was shown clearly that Ni-based catalysts prepared by impregnation method expressed the highest catalytic activity in CO methanation.

• Preventive Nutrition and Food Science
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• v.12 no.2
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• pp.95-102
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• 2007

To elucidate the relationship among body mass index, nutrient intake and blood antioxidant capacity in the postmenopausal period, 60 women residing in Iksan area were recruited. Body mass index (BMI) was calculated base on height and weight, and food and nutrient intakes were estimated by 24-hour recalls of 3 non-consecutive days. Parameters of antioxidant capacity including the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) and total antioxidant capacity (TA) were measured in fasting blood samples from the subjects. The average age, height, weight and BMI of the subjects were 65 years, 151.1cm, 59.5 kg and 26.0 m/kg$^2$, respectively. The macronutrient intake rate of carbohydrate : protein : fat were 65:17.5:17.5; the mean intakes of energy and protein were 1532.7 kcal (86.3% of RDA) and 67.1 g (122.0% of RDA) respectively. The mean intakes of phosphorus, vitamin A, niacin and vitamin C were higher than Recommended Daily Allowance (RDA) for Koreans. On the other hand, calcium and riboflavin intakes were only 84.6% and 70.4% of RDA. Among the parameters of antioxidant capacity, SOD activity was significantly lower in lean subjects (BMI<20) than in the normal or overweight subjects (BMI${\geq}$20) (p<0.05). TAs of the subjects with the highest intakes of vegetables and fruits were significantly higher than those of subjects with lower intakes (p<0.05). Antioxidant capacity was compared among subjects according to 3 different nutrient intake levels according percentage of RDA for Koreans for selected nutrients with the following results: The high protein and niacin groups exhibited significantly lower TA status than those of the other intake groups (p<0.05). In conclusion, the low BMI was associated with lower SOD activity in postmenopausal women. Higher consumption of fruits and vegetables was associated with higher TA. When protein and niacin intakes were excessive, SOD activity and TA tended to be low. SOD and TA, among antioxidant indexes, seemed to be mostly influenced by other factors. Therefore, more studies on the effects of nutritional intake and the activity of antioxidant enzyme should be conducted.

• Environmental Analysis Health and Toxicology
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• v.23 no.2
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• pp.129-138
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• 2008

The purpose of this study was to investigate the effects of frankincense oil in skin aging animal model. Skin aging was induced by both the irradiation of UVB and the application of squalene monohydroperoxide (Sq-OOH) to the back of experimental animals for 4 weeks. And at the same time experimental materials were applied topically. Six to seven weeks female SHR-1 hairless mice were divided into five groups including normal (N: saline), control (C: UVB+Sq-OOH+saline), vehicle control (VC: UVB+Sq-OOH+jojoba oil), positive control (PC: UVB+Sq-OOH+0.01% retinoic acid) and experimental (E: UVB+Sq-OOH+3% Frankincense oil) groups, five animals each group. Lipid lamella and lipid content in stratum corneum of the E group were almost intact with a regular arrangement which were similar to the N group. Collagen fibers in dermis of the E group were almost intact with a regular arrangement which were similar to the N group. Relatively much less number of mast cells and inflammatory cells were found in the E group compared to the C group. The activities of XO, SOD and CAT were no significant difference between the E and N groups. In conclusion, the application of frankincense oil to the skin aging animal model reduced both the generation of free radicals and the damage of skin tissues. Therefore, frankincense oil can be used practically for the prevention or improvement of skin aging in terms of health promotion and beauty for the people.

• Journal of Pharmacopuncture
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• v.17 no.3
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• pp.16-24
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• 2014

Objectives: Alcohol abuse is a public issue and one of the major causes of liver disease worldwide. This study was aimed at investigating the protective effect of Ganoderma lucidum pharmacopuncture (GLP) against hepatotoxicity induced by acute ethanol (EtOH) intoxication in rats. Methods: Sprague-Dawley (SD) rats were divided into 4 groups of 8 animals each: normal, control, normal saline pharmacopuncture (NP) and GLP groups. The control, NP and GLP groups received ethanol orally. The NP and the GLP groups were treated daily with injections of normal saline and Ganoderma lucidum extract, respectively. The control group received no treatment. The rats in all groups, except the normal group, were intoxicated for 6 hours by oral administration of EtOH (6 g/kg BW). The same volume of distilled water was administered to the rats in the normal group. Two local acupoints were used: Qimen (LR14) and Taechung (LR3). A histopathological analysis was performed, and the liver function and the activities of antioxidant enzymes were assessed. Results: GLP treatment reduced the histological changes due to acute liver injury induced by EtOH and significantly reduced the increase in the alanine aminotransferase (ALT) enzyme; however, it had an insignificant effect in reducing the increase in aspartate aminotransferase (AST) enzyme. It also significantly ameliorated the superoxide dismutase (SOD) and the catalase (CAT) activities. Conclusion: The present study suggests that GLP treatment is effective in protecting against ethanol-induced acute hepatic injury in SD rats by modulating the activities of ethanol-metabolizing enzymes and by attenuating oxidative stress.