• Journal of Life Science
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• v.25 no.10
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• pp.1164-1168
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• 2015

Previous research showed that chlorphenesin galactoside (CPN-Gal), a preservative in cosmetics, was safer than CPN against human skin cells [9]. To establish a stable and long-term process for CPN-Gal production, we investigated the repeated-batch process. In this process, β-gal-producing recombinant Escherichia coli cells were immobilized in calcium alginate beads, and CPN was converted to CPN-Gal by the transgalactosylation reaction. The process was conducted in a 300 ml flask, which contained E. coli cell-immobilized alginate beads, 33.8 mM of CPN, and 400 g/l of lactose. The pH and temperature were 7.0 and 40℃, respectively. During the repeated-batch operation, four consecutive batch operations were conducted successfully until 192 hr. The conversion yield of CPN to CPN-Gal was 64% during 192 hr, which was higher than the values in previous reports [3, 13]. Thereafter, however, the conversion yield gradually decreased until the operation was finished at 336 hr. Western blotting of immobilized E. coli cells revealed that β-gal gradually decreased after 192 hr. In addition, alginate beads were cracked when the operation was finished. It is probable that, including this loss of E. coli cells by cracks, deactivation, and product inhibition of E. coli β-gal might lead to a gradual decrease in the production of CPN-Gal after 192 hr. However, as the purification of β-gal is not necessary with β-gal-producing recombinant E. coli cells, β-gal-producing E. coli cells might be a practical and cost-effective approach for enzymatically synthesizing CPN-Gal. It is expected that this process will be extended to long-term production process of CPN-Gal for commercialization.

• Herbal Formula Science
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• v.25 no.4
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• pp.483-497
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• 2017

Background : Behavioral stress has been suggested as one of the significant factors that is able to disrupt physiological systems and cause depression as well as changes in various body systems. The stressful events can alter cognition, learning, memory and emotional responses, resulting in mental disorders such as depression and anxiety. Results : We used a restraint stress model to evaluate the alteration of behavior and stress-related blood parameter. The animals were randomly divided into two groups of five animals each group. Furthermore, we assessed the change of body weight to evaluate the locomotor activity as well as status of emotional and anxiety in mice. After 7 days of restraint stress, the body weight had significantly decreased in the restraint stress group compared with the control group. We also observed stress-associated behavioral alterations, as there was a significant decrease in open field and forced swim test, whereas the immobilization time was significantly increased in the stress group compared to the control group. We observed the morphological changes of neuronal death and microglia by immunohistochemistry and western blot. In our study restraint stress did not cause change in neuronal cell density in the frontal cortex and CA1 hippocampus region, but there was a trend for an increased COX-2 and iNOS protein expression and microglia (CD11b) in brain, which is restraint stress. Conclusion : Our study, there were significant alterations observed in the behavioral studies. We found that mice undergoing restraint stress changed behavior, confirming the increased expression of inflammatory factors in the brain.

• The Journal of Advanced Prosthodontics
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• v.3 no.3
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• pp.152-160
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• 2011

PURPOSE. This study was to investigate the effects of recombinant human platelet-derived growth factor (rhPDGF-BB) and heparin to titanium surfaces for enhancement of osteoblastic functions and inhibition of inflammation activity. MATERIALS AND METHODS. The anodized titanium discs, not coated with any material, were used as a control group. In heparinized-Ti group, dopamine was anchored to the surface of Ti substrates, and coated with heparin. In PDGF-Ti group, rhPDGF-BB was immobilized onto heparinized Ti surface. The surface morphologies were investigated by the scanning electron microscope in each group. The release kinetics of rhPDGF-BB were analyzed, and cytotoxicity tests for each group were conducted. The biocompatibilities were characterized by measuring cell proliferation, alkaline phosphatase activity, and calcium deposition using MG-63 cells. Statistical comparisons were carried out by one-way ANOVA tests. Differences were considered statistically significant at $^*$P<.05 and $^{**}$P<.001. RESULTS. The combination of rhPDGF-BB and heparin stimulated alkaline phosphatase activity and OCN mRNA expression in osteoblastic cells ($^*$P<.05 and $^{**}$P<.001). MG-63 cells grown on PDGF-Ti had significantly higher amounts of calcium deposition than those grown on anodized Ti ($^{**}$ P<.001). Heparinized Ti was more anti-inflammatory compared to anodized Ti, when exposed to lipopolysaccharide using the transcript levels of TNF-${\alpha}$ and IL-6 of proinflammatory cytokine ($^*$P<.05 and $^{**}$P<.001). CONCLUSION. The result of this study demonstrated that the incorporation of rhPDGF-BB and heparin onto Ti surface enhanced osteoblastic functions and inhibited inflammation.

• Korean Journal of Food Science and Technology
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• v.47 no.4
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• pp.438-445
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• 2015

The production of GABA was optimized by co-cultivation of immobilized Lactobacillus plantarum K154 (ILK) with Ceriporia lacerata cultures. The mycelial culture of C. lacerata was performed in a defined medium containing 3% glucose, 3% soybean flour, and 0.15% $MgSO_4$ in a submerged condition for 7 days at $25^{\circ}C$, resulting in the production of 29.7 g/L mycelia, 3.1 g/L exopolysaccharides, 2% (w/w) ${\beta}$-glucan, 68.96 unit/mL protease, and 10.37 unit/mL ${\alpha}$-amylase. ILK in C. lacerata culture showed viable cell counts of $3.13{\time}10^9CFU/mL$ for immobilized cells and $1.48{\time}10^8CFU/mL$ for free cells after 1 day. GABA production in the free and immobilized cells was 9.96 mg/mL and 6.30 mg/mL, respectively, after 7 days. A recycling test of ILK in the co-fermentation was consequently performed five times at $30^{\circ}C$ for 15 days, resulting in the highest production of GABA. GABA could also be efficiently overproduced by co-cultivation with the produced polysaccharides, ${\beta}$-glucan, peptides, and probiotics.

• Korean Journal of Food Science and Technology
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• v.22 no.6
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• pp.611-617
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• 1990

This study was conducted to breed a high vitamin $B_{12}$ producer by the fusion of protoplasts between Bacillus natto and Bacillus megaterium. Auxotrophic mutants of Bacillus natto SH-34 ($thr^-try^-rif^r$) and Bacillus megaterium BK-13 ($arg^-ade^-lys^-str^r$) which showed high protease activity and production of vitamin $B_{12}$, respectively, were isolated for the fusion experiment. Protoplasts were induced by incubating the cells with lysis solution containing $500{\mu}/ml$ lysozyme, and the ratio of protoplast and regeneration formation were ranged from 99% and 67%, respectively. Fusion frequencies of fusants between Bacillus natto SH-34 and Bacillus megaterium BK-13 were appeared in the ranges of $1.0{\times}10^{-5}$ under the treatment of 30% PEG 6000 containing 3% PVP. The fusant, MNF-72 showed the highest product yield of $7.85{\mu}g/g-cell\;vitamin\;B_{12}$ in production medium. For the improvement of productivity, the immobilization of fusants with sodium alginate was carried out. In batch and continuous fermentation systems, the productivity were determined to be $0.58{\mu}g/ml.hr\;and\;0.80{\mu}g/ml.hr\;vitamin\;B_{12}$ under optimum condition, respectivity.

• Korean Chemical Engineering Research
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• v.60 no.4
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• pp.574-581
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• 2022

Nanofibers comprising reduced graphene oxide (rGO) and Mo₂C/Mo₂N nanoparticles (Mo₂C/Mo₂N rGO NFs) were prepared for a functional interlayer of Li-S batteries (LSBs). The well-dispersed Mo₂C and Mo₂N nanoparticles in the nanofiber structure served as active polar sites for efficient immobilization of dissolved lithium polysulfide. The rGO nanosheets in the structure also provide conductive channels for fast ion/electron transport during charging-discharging and ensured reuse of lithium polysulfide during redox reactions through a fast charge transfer process. As a result, the cell assembled with Mo₂C/Mo₂N rGO NFs-coated separator and pure sulfur electrode (70 wt% of sulfur content and 2.1 mg cm^-2 of sulfur loading) showed a stable discharge capacity of 476 mA h g^-1 after 400 charge-discharge cycles at 0.1 C. Furthermore, it exhibited a discharge capacity of 574 mA h g^-1 even at a high current density of 1.0 C. Therefore, we believe that the proposed unique nanostructure synthesis strategy could provide new insights into the development of sustainable and highly conductive polar materials as functional interlayers for high performance LSBs.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.255-262
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• 2002

This experiment was performed to improve the stability of Lactobacillus fermentum YL-3 as a poultry probiotics. The culture conditions that improve acid tolerance of L. fermentum YL-3 were investigated by changing several factors such as medium composition, temperature, anaerobic incubation and culture time. Also, L. fermentum YL-3 was encapsulated with alginate, calcium chloride and chitosan. The stable culture conditions of L. fermentum YL-3 were obtained in anaerobic incubation using MRS media without tween 80 for 20 hour at $42^{\circ}C$. The capsule after treatment with 1% chitosan was formed close membrane by a bridge bond. Immobilization of L. fermentum YL-3 in capsule was observed by confocal laser scanning microscopy, and cell viability was $2.0{\times}10^9\;CFU/g$ above the average. L. fermentum YL-3 capsule after acid treated at pH 2.0 for 3 hour survived about 40%, but those encapsulated with 1% chitosan survived about 65%. Survival rate of capsule stored at room temperature decreased about $2{\sim}3$ log cycle during 3 weeks, but viability of capsule stored at $4^{\circ}C$ during 3 weeks maintained almost $10^8\;CFU/g$ levels.

• Journal of Marine Bioscience and Biotechnology
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• v.1 no.2
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• pp.91-97
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• 2006

For efficient removal of nitrogenous compounds produced in recirculating aquaculture system, the N removal characteristics of immobilized mixed microorganisms were investigated at various mixing ratios of photosynthetic bacteria (PSB) immobilized in PVA beads or CTA cubes and ammonium utilizing bacteria (AUB) immobilized in PVA beads. On the optimal medium of AUB, the maxium gas production rate was obtained at the mixing ratio of 10:40 (PSB:AUB), and the gas production rate increased as the portion of AUB beads in the mixed beads increased. When the mixing ratios of PSB:AUB beads were 50:0, 40:10, 25:25 and 10:40, the final pHs were measured to be 6.29, 6.01, 5.69 and 5.13, respectively. On the optimal medium of PSB, however, the volume and the rate of gas production decreased remarkably as the portion of AUB beads in the mixed beads increased. The final pH was measured to be approximately 6.5, regardless of the mixing ratio. In the reactions by the mixed culture of PSB cubes and AUB beads, all results showed the same tendency of those by the mixed culture of PSB and AUB beads, but the volume and the rate of gas production decreased remarkably, even with 0.2ml of gas production in control. From all the results, the use of mixed PSB and AUB beads at the ratio of 10:40 seems to be efficient to remove nitrogenous compounds in wastewater from recirculating aquaculture system.

• Korean Journal of Mineralogy and Petrology
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• v.34 no.3
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• pp.169-176
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• 2021

This study aimed to fundamentally understand structural changes of zeolite under pressure and in the presence of different pressure-transmitting media (PTM) for application studies such as immobilization of heavy metal cation or CO₂ storage using pressure. High-pressure X-ray powder diffraction study was conducted on the zeolite-W (K_6.4Al_6.5Si_25.8O₆₄× 15.3H₂O, K-MER) to understand linear compressibility and the bulk moduli in different PTM conditions. Zeolite-w is a synthetic material having the same framework as natural zeolite merlinoite ((K, Ca_0.5, Ba_0.5, Na)₁₀ Al₁₀Si₂₂O₆₄× 22H₂O). The space group of the sample was identified as I4/mmm belonging to the tetragonal crystal system. Water, carbon dioxide, and silicone-oil were used as pressure-transmitting media. The mixture of sample and each PTM was mounted in a diamond anvil cell (DAC) and then pressurized up to 3 GPa with an increment of ca. 0.5 GPa. Pressure-induced changes of powder diffraction patterns were measured using a synchrotron X-ray light source. Lattice constants, and bulk moduli were calculated using the Le-Bail method and the Birch-Murnaghan equation. In all PTM conditions, linear compressibility of c-axis (𝛽^c) was 0.006(1) GPa^-1 or 0.007(1) GPa^-1. On the other hand, the linear compressibility of a(b)-axis (𝛽^a) was 0.013(1) GPa^-1 in silicone-oil run, which is twice more compressible than the a(b)-axis in water and carbon dioxide runs, 𝛽^a = 0.006(1) GPa^-1. The bulk moduli were measured as 50(3) GPa, 52(3) GPa, and 29(2) GPa in water, carbon dioxide, and silicone-oil run, respectively. The orthorhombicities of ac-plane in the water, and carbon dioxide runs were comparatively constant, near 0.350~0.353, whereas the value decreased abruptly in the silicone-oil run following formula, y = -0.005(1)x + 0.351(1) by non-penetrating pressure fluid condition.