• The Journal of Korean Academy of Prosthodontics
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• v.25 no.1
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• pp.327-340
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• 1987

This study was performed to investigate the biocompatibility of several dental casting alloys (Gold, Dong Myung A-45, Dong Myung AP-35, Verabond, Rexillium, NPG) employing tissue culture. Fibroblast-like cells derived from the subcutaneous tissue of Sprague-Dawley rat were cultivated in DME medium with the addition of those alloys. Results were assessed by calculating the cell multiplication rate and relative growth rate and by observing the morphology of cells in the presence of the specimens. Gold was indicated to be most biocompatible with fibroblast-like cell. Dong Myung A-45 and Dong Myung AP-35 showed very similar effects on the cells as did Gold. Also there was a decrease in cytotoxicity of the alloys as the concentration of gold increased. Verabond and Rexillium showed a decreased in cell mutiplication rate as compared to low gold alloys. NPG exhibited the most severe cell toxicity among the tested alloys.

• Journal of Microbiology and Biotechnology
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• v.17 no.6
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• pp.905-912
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• 2007

A novel ${\beta}-glucosidase$ gene, bglA, was isolated from uncultured soil bacteria and characterized. Using genomic libraries constructed from soil DNA, a gene encoding a protein that hydrolyzes a fluorogenic analog of cellulose, 4-methylumbelliferyl ${\beta}-D-cellobioside$ (MUC), was isolated using a microtiter plate assay. The gene, bglA, was sequenced using a shotgun approach, and expressed in E. coli. The deduced 55-kDa amino acid sequence for bglA showed a 56% identity with the family 1 glycosyl hydrolase Chloroflexus aurantiacus. BglA included two conserved family 1 glycosyl hydrolase regions. When using $p-nitrophenyl-{\beta}-D-glucoside$ (pNPG) as the substrate, the maximum activity of the purified ${\beta}-glucosidase$ exhibited at pH 6.5 and $55^{\circ}C$, and was enhanced in the presence of $Mn^{2+}$. The $K_m\;and\;V_{max}$ values for the purified enzyme with pNPG were 0.16 mM and $19.10{\mu}mol/min$, respectively. The purified BglA enzyme hydrolyzed both pNPG and $p-nitrophenyl-{\beta}-D-fucoside$. The enzyme also exhibited substantial glycosyl hydrolase activities with natural glycosyl substrates, such as sophorose, cellobiose, cellotriose, cellotetraose, and cellopentaose, yet low hydrolytic activities with gentiobiose, salicin, and arbutin. Moreover, BglA was able to convert the major ginsenoside $Rb_1$ into the pharmaceutically active minor ginsenoside Rd within 24 h.

• Polymer(Korea)
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• v.25 no.1
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• pp.15-24
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• 2001

In this study, the effects of different glycol molar ratios of unsaturated polyester(UPE) resins on the curing behaviors were investigated. The cross linking process was checked or monitored by differential scanning calorimetry(DSC) and by viscoelastic properties of rigid-body pendulum model. The knife-edge from which the pendulum is suspended, is immersed in a reaction mixture, and the change of the viscoelastic behavior brings on those of the period(T) and logarithmic decrement(${\Delta}$) of the damped free oscillations of the pendulum. The values of T and ${\Delta}$ obtained are related to the dynamic modulus(E') and modulus loss(E'). The information on the viscoelastic behavior of unsaturated polyester(UPE) resins during the curing process are shown to illustrate the usefulness of the techniques. As the content of NPG in a propylene glycol(PG)/NPG glycol mixture increased, both the cycle time during cure and the change of damping during cure of UPE resin decreased.

• Journal of Microbiology and Biotechnology
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• v.18 no.5
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• pp.933-941
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• 2008

An extracellular $\beta$-glucosidase produced by Monascus purpureus NRRL1992 in submerged cultivation was purified by acetone precipitation, gel filtration, and hydrophobic interaction chromatography, resulting in a purification factor of 92-fold. A $2^2$ central-composite design (CCD) was performed to find the best temperature and pH conditions for enzyme activity. Maximum activity was observed in a wide range of temperature and pH values, with optimal conditions set at $50^{\circ}C$ and pH 5.5. The $\beta$-glucosidase showed moderate thermostability, was inhibited by $HgCl_2$, $K_2Cr_O_4$, and $K_2Cr_2O_7$, whereas other reagents including $\beta$-mercaptoethanol, SDS, and EDTA showed no effect. Activity was slightly stimulated by low concentrations of ethanol and methanol. Hydrolysis of p-nitrophenyl-$\beta$-D-glucopyranoside (pNPG), cellobiose, salicin, n-octyl-$\beta$-D-glucopyranoside, and maltose indicates that the $\beta$-glucosidase has broad substrate specificity. Apparently, glucosyl residues were removed from the nonreducing end of p-nitrophenyl-$\beta$-D-cellobiose. $\beta$-Glucosidase affinity and hydrolytic efficiency were higher for pNPG, followed by maltose and cellobiose. Glucose and cellobiose competitively inhibited pNPG hydrolysis.

• Proceedings of the Zoological Society Korea Conference
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• 1997.10b
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• pp.284.1-284
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• 1997

No Abstract, See Full Text

• The Journal of the Korean dental association
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• v.29 no.12 s.271
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• pp.956-959
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• 1991

연세대학교 치과대학 치과재료학교실에서는 최근 문제가 되고 있는 NPG 동합금에 대하여 시험한 내용과 아울러 지난 11월 1일에 있었던 대한치과의사협회 종합학술대회에서 가진 본 교실 주최의 특강 내용을 정리하여 게재하오니 임상에 많은 참고가 있으시기 바랍니다.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.11 no.2
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• pp.198-208
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• 2000

Objectives：This study was conducted to evaluate the effects of the attachment promotion program which was designed to promote attachment between autistic children and their mothers. The program was consisted of play activity centered mother-child interaction, educational activity for mothers by lecture, video-feedback session, and emotional supports. Methods：The subjects were consisted of 11 pairs of mother and child(7 for participant group：PG, 4 for non-participant group：NPG), who were 2-4 years-old autistic children. The data were collected by video-taping, behavioral observations, and analyzed by Wilcoxon Rank(Sign) Sum Test and Content Analysis. Results：The total attachment score increased from pre test to post-test of PG was significantly higher than that of NPG. The scores of attachment behaviors indicating proximity, mutuality and affect increased significantly(p<.05), while some behaviors indicating synchrony and jointattention did not. Especially the affectionate behaviors of PG demonstrated the most notable changes and they became more active, voluntary and reciprocal. After the program, the mother's nurturing behaviors of PG increased more than that of NPG, with no significant difference between two groups. The mother's behaviors to her child of PG became more child-centered, positively responsive, supportively expressive. As the attachment was promoted, there were also positive changes in the children's autistic behaviors with a great deal of individual differences. Conclusion：Our findings suggest that Mother-Child Attachment Promotion Program could be an effective early intervention model for autistic children.

• Proceedings of the Zoological Society Korea Conference
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• 1999.10b
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• pp.274.2-274
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• 1999

No Abstract, See Full Text

• Proceedings of the Zoological Society Korea Conference
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• 1999.10b
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• pp.281.2-281
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• 1999

No Abstract, See Full Text

• Applied Chemistry for Engineering
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• v.7 no.2
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• pp.341-349
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• 1996

To improve the dyeability of polyurethane (PU) resin, low molecular weight diols containing dye site in the molecular structure was added as a chain-extender. PU resin were synthesized with the variations in the chain extender, polyol type, and hard segment/soft segment (HS/SS) ratio. When HS/SS ratio is 1.4 and dimethylolpropionic acid(DMPA) or N-butyldiethanolamine (BDEA) was used as a chain extender, because of heterogeneity of reaction mechanical properties were diminished. But when N-methyldiethanolamine (MDEA) was used as a DCE, and HS/SS ratio lowed to 1.3, mechanical properties and dyeability improved. In particular, when linear type 1,4-BD was formulated with MDEA, hydrolysis resistance and mechanical properties of PTMG type PU was improved. And initial elasticity, tensile strength and elongation could be controlled by the variation of HS/SS ratio, DCE mixing ratio of 1,6-HD or NPG.