• Korean Journal of Veterinary Research
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• v.46 no.4
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• pp.305-313
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• 2006

The primary goal of the wound healing is rapid wound closure. Recent advances in cellular and molecular biology have greatly expanded our understanding of the biologic processes involved in wound repair and tissue regeneration. This study was conducted to develop a new sponge type of biomaterial to be used for either wound dressing or scaffold for tissue engineering. We designed to make a comparative study of the wound healing effect of silk fibroin/hyaluronic acid (SF/HA) blend sponge in full-thickness dermal injury model of rat. Two full-thickness excisions were made on the back of the experimental animals. The excised wound was covered with either the silk fibroin (SF), hyaluronic acid (HA) or SF/HA (7 : 3 or 5 : 5 ratio) blend sponge. On the postoperative days of 3, 7, 10 and 14, the wound area was calculated by image analysis software. Simultaneously, the tissues were stained with Hematoxylin-Eosin and Masson's trichrome methods to measure the area of regenerated epithelium and collagen deposition. In addition, we evaluated the degree of the epithelial cell proliferation using immunohistochemistry for proliferating cell nuclear antigen (PCNA). We found that the half healing time ($HT_{50}$) of SF/HA blend sponge treated groups were significantly decreased as compared with either those of SF or HA treatment group. Furthermore, SF/HA blend sponges significantly increased the size of epithelialization and collagen deposition as well as the number of PCNA positive cells on epidermal basement membrane as compared with those of control treatment. Especially, the 5 : 5 ratio group of SF/HA among all treatment groups was most effective on wound healing rate and histological studies. These results suggest that SF/HA blend sponges could accelerate the wound healing process through the increase of epithelialization, collagen deposition and basal cell proliferation in full thickness skin injury.

• Archives of Plastic Surgery
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• v.40 no.5
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• pp.530-535
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• 2013

Background Platelet-rich plasma (PRP) has more concentrated platelets than normal plasma (approximately 150-400${\times}10^3$ cell/dL). Platelets excrete several growth factors and cytokines that are associated with the healing and regeneration process. However, even though PRP is widely used, the mechanism or actual effect is presently unclear. Therefore, this study was performed to investigate the levels of growth factors and platelet concentration rate. Methods Autologous blood for preparing PRP was obtained from healthy subjects aged 25 to 35 years. The samples were divided into 4 experimental groups (inactivated whole blood, inactivated PRP, activated whole blood with thrombin and calcium chloride, and activated PRP). The platelet counts in the blood were analyzed and the growth factors were quantitatively measured. A statistical analysis was performed by using Dunn's multiple comparison test. Results In the blood cell analysis, the platelet count of the PRP group was approximately 4.25 times higher than that of the whole blood group. In the quantitative analysis of growth factors, the platelet-derived growth factor (PDGF)-AB, PDGF-BB, and transforming growth factor-${\beta}$ of the inactivated and activated PRP groups were higher than those of the inactivated and activated whole blood groups (P<0.05). Conclusions In this study, the platelet count and the levels of PDGF-AB and PDGF-BB in the PRP were determined. Further, more research is required on the bioactivity level of the growth factors secreted during the process of PRP preparation and the potency of growth factors that can be exerted physiologically in vivo.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.218-218
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• 2012

Nanocrystalline $SnO_2$ colloids are synthesized by hydrolysis of $SnCl_4{\cdot}5H_2O$ in aqueous ammonia solution. The synthesized $SnO_2$ nanoparticles with ca. 15 nm in diameter are coated on a fluorinedoped thin oxide (FTO) conductive substrate and heated at $550^{\circ}C$. The annealed $SnO_2$ film is treated with aqueous $TiCl_4$ solution, which is sensitzied with MK-2 dye (2-cyano-3-[5'''-(9-ethyl- 9H-carbazol-3-yl)-3',3'',3''',4-tetra-n-hexyl-[2,2',5',2'',5'',2''']-quater thiophen-5-yl]). Compared to bare $SnO_2$ film, the conversion efficiency is significantly improved from 0.22% to 3.13% after surface treatment of $SnO_2$ with $TiCl_4$, which is mainly due to the large increases in both photocurrent density from 1.33 to $9.46mA/cm^2$ and voltage from 315 to 634 mV. It is noted that little change in the amount of the adsorbed dye is detected from 1.21 for the bare $SnO_2$ to $1.28{\mu}mol/cm^2$ for the $TiCl_{4-}$ treated $SnO_2$. This indicates that the photocurrent density increased by more than 6 times is not closely related to the dye loading concentration. From the photocurrent and voltage transient spectroscopic studies, electron life time increases by about 13 order of magnitude, whereas electron diffusion coefficient decreases by about 3.6 times after $TiCl_4$ treatment. Slow electron diffusion rate offers sufficient time for regeneration kinetics. As a result, charge collection efficiency of about 40% before $TiCl_4$ treatment is improved to 95% after $TiCl_4$ treatment. The large increase in voltage is due to the significant increase in electron life time, associated with upward shift of fermi energy.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.4
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• pp.657-661
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• 2005

Various chemotherapeutic agents have been recommended for pulpotomy of primary teeth, and there are formocresol, ferric sulfate, and calcium hydroxide. Of those, formocresol has fixation effect of pulp tissue and high clinical success rate, so it is most commonly used agent. But formocresol has strong cytotoxic effects, thus many articles reported displacement and loss of permanent successor, amelogenesis imperfecta, mutation by general absorption, possibility of cancer induction. Recently, it has been reported that leakage by imperfect temporary sealing when FC-soaked cotton was inserted into the root canal caused necrosis of surrounding tissues. and that necrosis of alveolar bone related to the use of excessive formocresol. In this case, 2nd primary molar of upper left jaw was treated using formocresol in local clinic, but extracted because of lasting pain. Furthermore, symptoms didn't disappear so patient was refered to us. The patient was 8-year-old male, had foul odor from oral cavity and circular alveolar bone necrosis around the permanent successor' crown. Thus sequestrectomy was operated and observed through 19 months after operation, we found normal root development of permanent successor but no complete regeneration of alveolar bone defect and attached gingiva. Lesion of periodontal tissues by formocresol is irreversible, so we have to confirm the indication in using formocresol and pay attention to complete temporary sealing.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.1
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• pp.26-33
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• 2017

The objective of this study was to evaluate the characteristic of adsorption by using a meso-porous adsorbent (MPA), and investigate the removal efficiency of geosmin which taste and odor causing compounds in drinking water supplies through batch test. The results for the adsorption isotherm was analyzed by using the Langmuir equation and Freundlich equation, generally being applied. And the study showed that the both Langmuir and Freundlich equation explains the results better. Both of pseudo-first-order model and pseudo-second-order model were respectively applied for evaluation of kinetic sorption property of geosmin onto MPA. The adsorption experiment results using MPA showed that maximum adsorption capacity of MPA was lower 7 times than that of GAC, and adsorption rate of MPA was faster 11 times than that of GAC, on the basis of pseudo-first-order model. Therefore, it was determined that MPA was effectively able to remove geosmin in drinking water supplies in short EBCT condition, but regeneration cycle in MAP process was shorter than that in conventional process.

• Journal of Plant Biotechnology
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• v.32 no.2
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• pp.123-128
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• 2005

A series of experiments were performed to establish regeneration system through friable embryogenic callus (FFC) of Lilium longiflorum 'Nellie White'. Only hard and regular callus was induced from bulb scales on medium containing 2.0 mg/L dicamba and $30{\sim}90$ g/L sucrose. The induced hard callus was subcultured on medium with 2.0 mg/L dicamba and 30 g/L sucrose, and used as a material for induction of FEC. In order to induce FEC, induced hard and regular callus was chopped into $1{\sim}2\;mm$ segments, and re-cultured on medium with 2.0 mg/L dicamba and 90 g/L sucrose. FEC was induced from chopped hard calli by the subcultures of two months interval. The induction rate of FEC was enhanced when hard callus was subcultured on same medium. FEC was proliferated more than 5 times on medium with $1.0{\sim}2.0\;mg/L$ dicamba and 90 g/L sucrose. Bulblet differentiation from FEC was very favorable on MS medium supplemented with 0.1 mg/L BA, 1.0 mg/L NAA and 30 g/L maltose, but many differentiated bulblets were changed to vitrificated ones. The differentiation of normal bulblets was most effective on medium containing $0.5{\sim}1.0\%$ activated charcoal and 30 g/L sucrose.

• Journal of Periodontal and Implant Science
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• v.26 no.2
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• pp.414-428
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• 1996

The use of basic fibroblast growth factor which function as potent biologic mediators regulating numerous activities of wound healing has been suggested for the promotion of periodontal regeneration. The mitogenic effects of basic fibroblast growth factor on human periodontal ligament cells and human gingival fibroblasts were evaluated by determining the incorporation of 5-Bromo-2'deoxy-uridine into DNA of the cells in a dose -dependent manner. The cells which were prepared were the primary cultured gingival fibroblasts and periodontal ligament cells from human the fourth or sixth subpassages were used in the experiments. The cells which were seeded DMEM contain 10% FBS. The added concentrations of basic fibroblast growth factor were 0.1, 1, 10, 50, $l00{\eta}g/ml$ and basic fibroblast growth factor were added to the quiescent cells for 24 hours, 48 hours and 72 hours. They were labeled with $10{\mu}l/200{\mu}l$ 5Bromo-2'-deoxy-uridine for the last 6 hours of each culture. The results of the five determinants were presented as mean and S.D.. The results were as follows. : The DNA synthetic activity of human gingival fibroblasts was increased dose dependently by basic fibroblast growth factor at 24 hours, 48 hours and 72 hours. The similar mitogenic effects were at the 24 and 48 hours of basic fibroblast growth factor, but the DNA synthetic activity of human gingival fibroblasts generally decreased at 72 hours. The DNA synthetic activity of human periodontal ligament cells was increased dose dependently to $50{\eta}g/ml$ by basic fibroblast growth factor at 24, 48 and 72 hours, but the DNA synthetic activity decreased at $l00{\eta}g/ml$ of each hour. Generally the maximum mitogenic effects were at the 48 hours application of basic fibroblast growth factor. The DNA synthetic activity of human periodontal ligament cells generally decreased lower at 72 hours than at 24, 48 hours the application of basic fibroblast growth factor. In the comparison of DNA synthetic activity between human gingival fibroblasts and human periodontal ligament cells, human periodontal ligament cells had slightly higher proliferation activity than human gingival fibroblasts for a longer time at the high dosage of the basic fibroblast growth factor.In conclusion, basic fibroblast growth factor have important roles in the stimulation of DNA synthesis in human periodontal ligament cells and human gingival fibroblasts, and thus may be useful for clinical applications in periodontal regenerative procedures.

• Clean Technology
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• v.20 no.4
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• pp.383-389
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• 2014

$CO_2$ absorption processes have a good potential for large scale capture of $CO_2$ but a large amount of absorbing solution has to be regenerated, undesirably increasing the consumption of energy such as sensible heat and latent heat of vaporization. In this study, a cooling crystallization process which would separate the $CO_2$-rich potassium bicarbonate crystals from $CO_2$-lean water was developed to reduce the energy penalty. Sterically hindered alkanolamine additives were used to enhance the $CO_2$ removal efficiency and their antisolvent effect on the crystallization was found in a continuous cooling crystallizer. The production yields of crystals were increased in the sequence of 2-amino-2-methyl-1-propanol (AMP) < 2-amino-2-methyl-1,3-propanediol (AMPD) < 2-amino-2-hydroxymethyl-1,3-propanediol (AHPD), which are related to the number of hydroxyl groups in the additive molecules. Using $^{13}carbon$ nuclear magnetic resonance, the additives favored the formation of bicarbonate ions by steric hindrance effect and increased the supersaturation of $KHCO_3$. It is shown that the additives increase the mean size of crystals and crystal growth rate by increasing supersaturation. The additives are promising for enhancing the $CO_2$ removal efficiency and reducing the regeneration energy cost of $CO_2$ absorbing solution by promoting $KHCO_3$ crystallization.

• Clean Technology
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• v.20 no.2
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• pp.179-188
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• 2014

The effect of desorption pressure on $CO_2/N_2$ breakthrough behaviors for 4 different adsorbents was studied at a fixed bed. Zeolite 3A, 4A, 5A, and 13X pellets were used as adsorbents. Cyclic operations were executed with varying desorption pressure from vacuum (0 bar) to 3 bar while other conditions such as adsorption step pressure (3 bar), temperature (293 K), composition ($CO_2:N_2=10:90$vol%) and flow rate (400 ccm) were fixed at constant values. Each adsorption and desorption step was set as 80 min, which totaled up to 160 min per a cycle. 5 cycles with adsorption and desorption steps were run overall. After the experiment, breakthrough time, saturation time, and adsorption amount were measured and compared in order to find an optimum adsorbent and a proper operating condition for a post combustion $CO_2$ capture process.

• Clean Technology
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• v.24 no.1
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• pp.50-54
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• 2018

In this work, N-methyl-2-pyrrolidone (NMP) was added into diethylenetriamine (DETA) aqueous solution for high $CO_2$ loading via phase splitting of absorbents during $CO_2$ absorption. Immiscible two phases were formed in the range of more than 30 wt% of NMP in 2 M DETA + NMP + water absorbents because of low solubility of DETA-carbamate in NMP solution. As the composition of NMP in the absorbents increased, the difference of $CO_2$ loading between each phase increased and the volume of bottom phase decreased. In $CO_2$ absorption in packed column by 2 M DETA + NMP + water absorbents, the absorption rate decreased in the range of more than 40 wt% of NMP. It is due to the increasing of mass transfer resistance in liquid film of absorbents at the high concentration of NMP. DETA + NMP + water absorbent is expected as the promising one for reducing the regeneration energy of absorbents according to volume reduction of $CO_2-rich$ phase.