• Journal of Microbiology and Biotechnology
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• v.23 no.2
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• pp.218-224
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• 2013

The aldo-keto reductases catalyze reduction reactions using various aliphatic and aromatic aldehydes/ketones. Most reductases require NADPH exclusively as their cofactors. However, NADPH is much more expensive and unstable than NADH. In this study, we attempted to change the five amino acid residues that interact with the 2'-phosphate group of the adenosine ribose of NADPH. These residues were selected based on a docking model of the YOL151W reductase and were substituted with other amino acids to develop NADH-utilizing enzymes. Ten mutants were constructed by site-directed mutagenesis and expressed in Escherichia coli. Among them, four mutants showed higher reductase activities than wild-type when using the NADH cofactor. Analysis of the kinetic parameters for the wild type and mutants indicated that the $k_{cat}/K_{m}$ value of the Asn9Glu mutant toward NADH increased 3-fold. A docking model was used to show that the carboxyl group of Glu 9 of the mutant formed an additional hydrogen bond with the 2'-hydroxyl group of adenosine ribose. The Asn9Glu mutant was able to produce (R)-ethyl-4-chloro-3-hydroxyl butanoate rapidly when using the NADH regeneration system.

• Journal of agriculture & life science
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• v.45 no.2
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• pp.51-59
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• 2011

This study was conducted to analysis the growth characteristics and the diameter at breast height (10 cm) reached ages in natural stand and platation for the optimal planting density and planting timing of Acer mono for. rubripes. There was high correlation between the DBH and crown diameter (E-W: r=0.82, S-N: r=0.76) in natural stand, and between the DBH and crown diameter (E-W: r=0.76, S-N: r=0.90) in plantation. In natural stand, average reached age on DBH 10 cm was $21.1{\pm}7.0$, and was $9.2{\pm}1.3$ in plantation. Therefore, the collectable timing of sap in artificial planting short approximately 2.3 times over the natural regeneration.

• ETRI Journal
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• v.34 no.3
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• pp.352-360
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• 2012

This paper proposes a low-cost, low-power, and high-capacity optical-electrical-optical-type reach extender that can provide 3R frame regeneration and remote management to increase the reach and split ratio with no change to a legacy time division multiple access passive optical network. To provide remote management, the extender gathers information regarding optical transceivers and link status per port and then transmits to a service provider using a simple network management protocol agent. The extender can also apply to an Ethernet passive optical network (E-PON) or a gigabit-capable PON (G-PON) by remote control. In a G-PON, in particular, it can provide burst mode signal retiming and burst-to-continuous mode conversion at the upstream path through a G-PON transmission convergence frame adaptor. Our proposed reach extender is based on the quad-port architecture for cost-effective design and can accommodate both the physical reach of 60 km and the 512 split ratios in a G-PON and the physical reach of 80 km and the 256 split ratios in an E-PON.

• Journal of Periodontal and Implant Science
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• v.31 no.1
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• pp.193-209
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• 2001

The prognosis of transplanted teeth is strongly related with periodontal healing. Several experimental studies showed that the application of enamel matrix derivatives on periodontitis-affected root surfaces resulted in periodontal regeneration. The purpose of this study was to determine the effect of enamel matrix derivatives on periodontitis-affected root surfaces prior to transplantation in dogs. Class III Furcation defects were surgically created on the left second, the third and the fourth premolar in the mandibles of nine mongrel dogs and experimental periodontitis was induced by placing small cotton pellets into defects for 3 weeks. Periodontitis-affected roots were treated by scaling and planing and the coronal portions were removed. Each root was extracted and implanted into recipient bed prepared in the contralateral premolar area. The transplanted roots were grouped according to the treatment modalities; Group I- roots treated with saline only, Group II- roots conditioned by neutral EDTA, and Group III- roots conditioned by neutral EDTA and enamel matrix derivatives ($EMDOGAIN^{(R)}$, BIORA Co., Sweden). The animals were sacrificed at 1 week, 3 weeks, and 10 weeks after transplantation and decalcified specimens were prepared for histologic examination. In Group I, healing was most frequently characterized by root resorption and ankylosis. In Group II, with root resorption and ankylosis in a few specimens, connective tissue attachment was partly seen on denuded root surface, but no cementum formation was seen. In Group III, there was regeneration by new cementum and periodontal ligament on denuded root surface, although slight root resorption and ankylosis were found in a few specimens. This result suggests that enamel matrix derivatives treatment on periodontitis-aggected root surface could reduce the frequency of root resorption and ankylosis and contribute to periodontal regeneration, and might be useful for autologous transplantation.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.45 no.2
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• pp.97-107
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• 2019

Objectives: Small animal maxillofacial models, such as non-segmental critical size defects (CSDs) in the rabbit mandible, need to be standardized for use as preclinical models of bone regeneration to mimic clinical conditions such as maxillofacial trauma. The objective of this study is the establishment of a mechanically competent CSD model in the rabbit mandible to allow standardized evaluation of bone regeneration therapies. Materials and Methods: Three sizes of bony defect were generated in the mandibular body of rabbit hemi-mandibles: $12mm{\times}5mm$, $12mm{\times}8mm$, and $15mm{\times}10mm$. The hemi-mandibles were tested to failure in 3-point flexure. The $12mm{\times}5mm$ defect was then chosen for the defect size created in the mandibles of 26 rabbits with or without cautery of the defect margins and bone regeneration was assessed after 6 and 12 weeks. Regenerated bone density and volume were evaluated using radiography, micro-computed tomography, and histology. Results: Flexural strength of the $12mm{\times}5mm$ defect was similar to its contralateral; whereas the $12mm{\times}8mm$ and $15mm{\times}10mm$ groups carried significantly less load than their respective contralaterals (P<0.05). This demonstrated that the $12mm{\times}5mm$ defect did not significantly compromise mandibular mechanical integrity. Significantly less (P<0.05) bone was regenerated at 6 weeks in cauterized defect margins compared to controls without cautery. After 12 weeks, the bone volume of the group with cautery increased to that of the control without cautery after 6 weeks. Conclusion: An empty defect size of $12mm{\times}5mm$ in the rabbit mandibular model maintains sufficient mechanical stability to not require additional stabilization. However, this defect size allows for bone regeneration across the defect. Cautery of the defect only delays regeneration by 6 weeks suggesting that the performance of bone graft materials in mandibular defects of this size should be considered with caution.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.2
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• pp.105-109
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• 2015

NgR1, a Nogo receptor, is involved in inhibition of neurite outgrowth and axonal regeneration and regulation of synaptic plasticity. P19 embryonal carcinoma cells were induced to differentiate into neuron-like cells using all trans-retinoic acid and the presence and/or function of cellular molecules, such as NgR1, NMDA receptors and STAT3, were examined. Neuronally differentiated P19 cells expressed the mRNA and protein of NgR1, which could stimulate the phosphorylation of STAT3 when activated by Nogo-P4 peptide, an active segment of Nogo-66. During the whole period of differentiation, mRNAs of all of the NMDA receptor subtypes tested (NR1, NR2A-2D) were consistently expressed, which meant that neuronally differentiated P19 cells maintained some characteristics of neurons, especially central nervous system neurons. Our results suggests that neuronally differentiated P19 cells expressing NgR1 may be an efficient and convenient in vitro model for studying the molecular mechanism of cellular events that involve NgR1 and its binding partners, and for screening compounds that activate or inhibit NgR1.

• Korean Chemical Engineering Research
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• v.49 no.2
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• pp.244-249
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• 2011

In this study, performance and economic analysis of 500 MWe coal-fired power plant with $CO_{2}$ capture process was performed. For this purpose, chemical absorption method which is commercially available and most suitable for thermal power plant was studied and a criteria for technical and economic assessment of power plants suggested by IEA Greenhouse Gas R&D Programme was used. And we performed the sensitivity analysis focused on regeneration energy which exceed half of the total capture energy. Based on MEA(Monoethanoleamine) as a main chemical solvent and 3.31 GJ/ton$CO_{2}$ regeneration energy in the stripper, net power efficiency was reduced from 41.0% (no capture) to 31.6%(with capture) and the cost of $CO_{2}$ avoided was estimated 43.3 $/ton$CO_{2}$. And in case of 2.0 GJ/ton$CO_{2}$ regeneration energy, the cost of $CO_{2}$ avoided was calculated as 36.7 $/ton$CO_{2}$.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.38
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• pp.26.1-26.6
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• 2016

Background: Xenologous or synthetic graft materials are commonly used as an alternative for autografts for guided bone regeneration. The purpose of this study was to evaluate effectiveness of carbonate apatite on the critical-size bone defect of rat's calvarium. Methods: Thirty-six critical-size defects were created on 18 adult male Sprague-Dawley rat calvaria under general anesthesia. Calvarial bones were grinded with 8 mm in daimeter bilaterally and then filled with (1) no grafts (control, n = 10 defects), (2) bovine bone mineral (Bio-$Oss^{(R)}$, Geistlich Pharma Ag. Swiss, n = 11 defects), and (3) hydroxyapatite ($Bongros^{(R)}$, Bio@ Inc., Seongnam, Korea, n = 15 defects). At 4 and 8 weeks after surgery, the rats were sacrificed and all samples were processed for histological and histomorphometric analysis. Results: At 4 weeks after surgery, group 3 ($42.90{\pm}9.33%$) showed a significant difference (p < 0.05) compared to the control ($30.50{\pm}6.05%$) and group 2 ($28.53{\pm}8.62%$). At 8 weeks after surgery, group 1 ($50.21{\pm}6.23%$), group 2 ($54.12{\pm}10.54%$), and group 3 ($50.92{\pm}6.05%$) showed no significant difference in the new bone formation. Conclusions: $Bongros^{(R)}$-HA was thought to be the available material for regenerating the new bone formation.

• The Korean Journal of Mycology
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• v.26 no.2 s.85
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• pp.275-280
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• 1998

Factors affecting protoplasts isolation and regeneration of Fomitella fraxinea were investigated. Lytic enzyme mixture of Novozym 234, Cellulase onozuka R-10 and ${\beta}-Glucuronidase$ was found to be the best for the protoplasts isolation. Osmotic stabilizer of 0.6 M sucrose was observed as the best for protoplasts isolation. The highest number of protoplasts was obtained from the F. fraxinea mycelium with lytic enzyme mixture and osmotic stabilizer that had been cultured for 3 hours. The highest regeneration rate of 0.02 % was achieved when the 0.6 M sorbitol was employed as osmotic stabilizer.

• Korean Journal of Plant Tissue Culture
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• v.22 no.3
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• pp.175-182
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• 1995

Rice is one of the most successful monocot in regenerating fertile and genetically stable transgenic plants. However there is no report of a rice line developed in Korea that can be used for regeneration of fertile and genetically stable transformants. In this paper we first demonstrate that a Korean variety Nakdongbyeo, is suitable to obtain transgenic rice plants. Protoplasts from embryogenic suspension cultures were co-transformed with HPT (hygromycin phosphotransferase) and GUS ($\beta$-glucuronidase) genes in separate plasmids in the presence of PEG (polyethylene glycol). In 5 independent experiment, the average frequency of calli showing hygromycin resistance were 1.73%. Plantlets were regenerated from the Hy $g^{R}$ calli. The average efficiency of plantlet regeneration was apprbximately 27%. Based on the GUS activities of hygromycin resistant calli, ca.35% of the resistant calli carried active GUS genes. The R0 transgenic plantlets were grown to maturity and Rl seeds were obtained. By examining the in siぉ activity of GUS in Rl seeds and seedlings, we confirmed that the GUS transgene driven by a CaMV 35S (cauliflower mosaic virus) promoter showed proper expression patterns. We also confirmed Mendelian segregation of the HPT transgene in the Rl generation.n.