• Journal of Periodontal and Implant Science
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• v.29 no.3
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• pp.553-560
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• 1999

The aim of the present study was to evaluate the effect of the expanded polytetrafluoroethylene (e-PTFE) membrane exposure on the initial healing of the periodontal tissue in guided tissue regeneration (GTR) procedure. 90 sites selected from 90 patients were treated with gingival flap surgery supported by an e-PTFE membrane. The material included angular bony defects with probing attachment loss of > 5mm or degree II furcation involvement. Treated sites were classified with membrane exposure group and non-exposure group at membrane removal and evaluated healing type. The results were obtained as follows. 1. e-PTFE membrane was exposed at 61 sites (67.8%) among 90 sites. 2. Thirteen sites (14.4%) depicted rapid healing type, 65 sites (72.2%) depicted typical healing type, 9 sites (10%) showed delayed healing type and 3 sites (3.3%) were categorized as adversed healing type. 3. In e-PTFE membrane exposure group, 1 site (1.6%), 51 sites (83.6%), 6 sites (9.8%) and 3 sites (4.9%) showed rapid healing type, typical healing type, delayed healing type and adverse healing type respectively. 4. In e-PTFE membrane non-exposure group, 12 sites (41.3%), 14 sites (48.3%) and 3 sites (10.3%) showed rapid healing type, typical healing type and delayed healing type respectively. Adverse healing type was not observed. 5. The rate of favourable healing between e-PTFE membrane exposure group and non-exposure group was not statistically significant(p=0.56). These results suggest that the prevention of membrane exposure may be important to obtain rapid healing type. However favourable healing could be obtained with stringent infection control program even if membrane was exposed.

• Applied Chemistry for Engineering
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• v.2 no.1
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• pp.38-46
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• 1991

Regeneration of Ni catalyst deactivated by carbon-deposition and sulfur-poisoning was studied. When a carbon-deposited catalyst was regenerated by hydrogen, the final recovery of catalytic activity for benzene hydrogenation was large but relatively long period of regeneration was required, and futhermore the deposited carbon could not be removed completely. In case of oxygen-treatment, the regeneration rate was high and the deposited carbon could be removed almost completely after a subsequent reduction treatment. When a sulfur-poisoned catalyst was regenerated by hydrogen and water vapor, the catalytic activity was not recovered. The regeneration treatment with oxygen at $650^{\circ}C$ recovered the catalytic activity up to 60 % of the initial value. When $Cl^-$ was added to oxygen, the activity was easily recovered to 45 % of the initial value even after treatment at $500^{\circ}C$. Sintering of the dispersed Ni particles was enhanced by water vapor but was hindered by oxygen and chlorine addition.

• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.3
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• pp.174-182
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• 2008

As the survey and the analysis the research can offer the characteristic methods for regeneration in the city of Busan. To figure out the functional regions of city center the research has analyzed 15 Dongs in city center and 12 Dongs in sub centers to find out the donut phenomenon and the regeneration of city center. The survey has chosen 22 variation factors using factor analysis. Major factors in each year are shown 4 factors, presenting 80.4% of the accumulated explanation rate. These factors explain residental centered, commercial centered, management centered, and development centered factor. The donut phenomenon emerges in the city centers as a residential function, and the phenomenon occurs in the sub centers as commercial or managerial function. So it is necessary to plan the regeneration of the total city center owing to the total donut phenomenon regarding the functions. And the methods to regenerate city centers should be established according to the various regional characterizations.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.1
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• pp.205-217
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• 2007

Donut phenomenon of city centers has resulted from the decreasing residential population and the fluid population with curved commercial function, but the analysis can bring other problems owing to the simplified method. And As the survey and the analysis the research can offer the characteristic methods for regeneration in the city of Busan. To figure out the functional regions of city center the research has analyzed 15 Dongs in city center of the three years of 1996, 2000 and 2004 to find out the donut phenomenon and the regeneration of city center. The survey has chosen 20 variation factors using factor analysis and cluster analysis. Major factors in each year are shown 3 factors, presenting 84.2%, 87.1% and 85.5% of the accumulated explanation rate. These factors explain residential centered, commercial centered, and management centered factor. The results are as following. First, it is necessary to plan the regeneration of the total city center owing to the total donut phenomenon regarding the functions. Second, the methods to regenerate city centers should be established according to the various regional characterizations.

• Journal of Periodontal and Implant Science
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• v.43 no.6
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• pp.291-300
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• 2013

Purpose: Calcium phosphate (CaP)-coated implants promote osseointegration and survival rate. The aim of this study was to (1) analyze the dissolution behavior of the residual CaP particles of removed implants and (2) evaluate bone apposition of CaP-coated machined surface implants at the early healing phase. Methods: Mandibular premolars were extracted from five dogs. After eight weeks, the implants were placed according to drilling protocols: a nonmobile implant (NI) group and rotational implant (RI) group. For CaP dissolution behavior analysis, 8 implants were removed after 0, 1, 2, and 4 weeks. The surface morphology and deposition of the coatings were observed. For bone apposition analysis, block sections were obtained after 1-, 2-, and 4-week healing periods and the specimens were analyzed. Results: Calcium and phosphorus were detected in the implants that were removed immediately after insertion, and the other implants were composed mainly of titanium. There were no notable differences between the NI and RI groups in terms of the healing process. The bone-to-implant contact and bone density in the RI group showed a remarkable increase after 2 weeks of healing. Conclusions: It can be speculated that the CaP coating dissolves early in the healing phase and chemically induces early bone formation regardless of the primary stability.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.4
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• pp.275-279
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• 2010

Introduction: Guided bone regeneration (GBR) is a common procedure for the treatment of bone defects and bone augmentation. The nonresorbable barriers are well-documented barriers for GBR because of their stability and malleability. However, few GBR studies have focused on the different types of non-resorbable barriers. Therefore, this study examined the clinical results of different non-resorbable barriers for GBR; expanded polytetrafluoroethylene (e-PTFE) (TR-Gore Tex, Flagstaff, AZ, USA), and high-density polytetrafluoroethylene (d-PTFE) (Cytoplast membrane, Oraltronics, Bremen, Germany). Materials and Methods: The analysis was performed on patients treated with GBR and implant placement from January 2007 to October 2007 in the department of the Seoul National University Bundang Hospital. The patients were divided into two groups based on the type of non-resorbable barrier used, and the amount of bone regeneration, marginal bone resorption after prosthetics, implant survival rate and surgical complication in both groups were evaluated. Results: The implants in both groups showed high survival rates, and the implant-supported prostheses functioned stably during the follow-up period. During the second surgery of the implant, all horizontal defects were filled with new bone, and there was no significant difference in the amount of vertical bone defect. Conclusion: In bone defect areas, GBR with non-resorbable barriers can produce favorable results with adequate postoperative management. There was no significant difference in bone regeneration between e-PTFE and d-PTFE.

• Korean Journal of Plant Tissue Culture
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• v.21 no.2
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• pp.117-121
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• 1994

The optimal level of growth regulator for callus initiation stem explants was BAP 0.1mg/L combined with 2,4-D 1.0 mg/L in Murashige and Skoog (MS) medium supplemented with 30g/L sucrose and 10g/L agar, and that for cell growth was BAP 0.1+2,4-D 0.5 mg/L in MS liquid medium. The regeneration frequency of P. oleracea cells was significantly increased by subjecting the cells to dessication for 1and 2 h up to 83%, respectively, as compared with untreated control showing 61%. Cell viability and survival rate was inhibited by pretreatment of 0.6% NaCl for 2 days, while regeneration ability was not affected by the treatment. Pretreatment of 100g/L sucrose for 2 days markedly stimulated the regeneration of cells up to 81%. These results suggest that in addition to physiological changes, water stress resulted from dessication and high concentration of sucrose and NaCl is closely related to the regeneration of P. oleracea cultured cells.

• Journal of Plant Biotechnology
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• v.37 no.2
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• pp.228-235
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• 2010

The establishment of cell suspension culture and plant regeneration of the halophytic Leymus chinensis (Trin.) are described in this study for the first time. Callus induction solid medium containing Murashige and Shoog (MS) basic salt, $2.0\;mg\;l^{-1}$ 2,4-dichlorophenoxyacetic acid (2,4-D), and $5.0\;mg\;l^{-1}$ L-glutamic acid with $30.0\;g\;l^{-1}$ sucrose and $4.0\;g\;l^{-1}$ gelrite for solidification induced the highest rate of cell division in Type 1 callus among calli of various types. Liquid medium with the same hormone distribution was therefore, used for cell suspension culture from Type 1 callus. Over a 30 d suspension culture at 100 rpm, great amounts of biomass were accumulated, with 71.07% average daily increment and 22.32-fold total fresh weight increment. Comparison of before and after suspension culture, the distribution of different size callus pieces and the maintenance of callus type were basically unaltered, but a slight increase in relative water contents was observed. To induce the potential of plant regeneration, the directly transferring on plant regeneration solid medium containing MS basic salt, $0.2\;mg\;l^{-1}$ $\alpha$-naphthalene acetic acid (NAA), $2.0\;mg\;l^{-1}$ kinetin (Kn), and $2.0\;g\;l^{-1}$ casamino acid and indirectly transferring were simultaneously performed. Even now growth rates of suspension-derived callus on solid medium were approximately half of those of Type 1 callus, but faster somatic embryogenesis was observed. Rooting of all regenerated shoots was successfully performed on half-strength MS medium. All plants appeared phenotypically normal.

• Korean Journal of Medicinal Crop Science
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• v.15 no.1
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• pp.62-66
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• 2007

Plant Regeneration via organogenesis from leaf disk of Korean dandelion was investigated. Leaf disk cultured on MS medium with various combinations of BA (0-4 mg/L) and 2,4-D (0-1 mg/L). Shoot regeneration from leaf explant was observed after 3 weeks of culture. The highest shoot regeneration frequency from leaf disk was obtained with 2 mg/L BA. To analyze the effect of leaf age along shoot formation, we measured number of shoots per explant, shooting rate, fresh and dry weight of leaf explant. The highest number of shoots (11.5) per explant were obtained leaf from 7 weeks old plantlets after seed germination. The regenerated shoots were transferred in 1/2 MS medium with 0.5 mg/L NAA for root formation. Regeneratied plantlets thought organogenesis were growing to whole plants in the pots with acclimation.

• Korean Journal of Microbiology
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• v.25 no.4
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• pp.274-281
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• 1987

The effects of bovine serum albumin, myoinositol and ergosterol on protoplast formation, regeneration and fusion from auxotrophic mutants of Candida pseudotropicalis were examined. Frequency of protoplast formation ranged from 48 to 98% depending on auxotrophic types. When myoinositol (0.5mg/ml) and ergosterol (0.1mg/ml) were supplemented in the medium of cell growth, and bovine serum albumin (4mg/ml)was added to protoplasting buffer, 50-100% of cells were converted to protoplasts. Such a treatment of three additives improved 2.2-3.0 fold of regeneration rate of protoplasts. The fusion frequencies between complementary auxotrophs ranged from $7.0\times 10^{-4}$ to $1.5\times 10^{-3}$ in the optimal conditions. These values showed 1.9-2.3 fold increase when compared with fusion frequencies obtained without the treatment of additives. These results suggested that these comsion frequencies obtained without the treatment of additives. These results suggested that these xompounds may improve protoplast regeneration and fusion between complementary auxotrophs used in this study.