• Journal of the Korean Ceramic Society
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• v.49 no.1
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• pp.72-77
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• 2012

In the preparation of a hydroxyapatite [HAp]/gelatin [GEL] nanocomposite, the GEL matrix in aqueous solution of $H_3PO_4$ was modified by the introduction of aspartic acid [Asp], asparagine [Asn], and glycine [Gly]. The addition of Asp, Asn and Gly greatly affected the slurry formation of HAp/GEL nanocomposite and the resulting dry body showed variations in toughness with the addition of the different amino acids. The introduction of Asn into HAp/GEL nanocomposite was effective for producing the organic-inorganic interaction between HAp and GEL, and caused the increase of toughness. The formation reaction of the modified HAP/GEL nanocomposites was investigated by using XRD and FT-IR. The organic-organic interaction between the GEL matrix and the additives of Asp, Asn and Gly was confirmed from FT-IR analysis, and the organic-inorganic interaction between HAp nanocrystallites and the modified GEL matrix was also discussed, using FT-IR spectra patterns. Nanocrystallites of HAp were covalently bound with the GEL macromolecules and differently influenced by the modification species of Asp, Asn, and Gly.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.10
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• pp.1404-1408
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• 2006

In order to investigate the genetic marker associated with economic performance in Hanwoo (Korean Brown Cattle), proteomic approach was used. Breeding values were estimated from performance tested steers. The top 20 and bottom 19 steers based on carcass weight (CW), eye muscle area (EMA), backfat thickness (BF) and marbling score (MS) evaluation for one progeny testing period was used. Meat samples dissected from longissimus dorsi muscles were taken from the slaughter house and analyzed for two-dimensional gel electrophoresis. A total of 102 significant spots out of total 146 on each gel were detected and compared with the reference gel (synthetic gel) to be evaluated. Four candidate spots for marbling score were identified: 205, 84, 204 and 198. The study confirmed the relationship between breeding values of economic traits of Hanwoo cattle and spot intensity.

• Journal of Applied Biological Chemistry
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• v.56 no.2
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• pp.95-100
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• 2013

Soil microbes are important integral components of soil ecosystem which have significant and diverse role in organic matter decomposition, nitrogen cycling, and nitrogen fixation. In this study an effective denaturing gradient gel electrophoresis (DGGE) method was employed for paddy soil microbial diversity survey. For optimum paddy soil microbial DNA extraction, different methods such as Lysis buffer, skim milk bead, sodium phosphate buffer, Epicentre Soil Master DNA extraction kit (Epicentre, USA) and Mo Bio Power Soil DNA kit (MO BIO, USA) methods were utilized. Among all the method, using Mo Bio Power Soil kit was most effective. DGGE analysis of Bacteria was carried out at 6% polyacylamide gel and 45-60% denaturing gradient in the optimal conditions. Whereas DGGE analysis of fungi was done at 6% polyacrylamide gel and 45-80% denaturing gradient in the optimal conditions. By applying the above assay, it was found that variation within the microbial community of paddy soil occurs by a factor of time. DGGE assay used in this study through for a variety of soil microbial analysis suggests the potential use of this method.

• Korean Journal of Materials Research
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• v.29 no.3
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• pp.183-188
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• 2019

Flexible dye-sensitized solar cells using binder free $TiO_2$ paste for low temperature sintering are developed. In this paste a small amount of titanium gel is added to a paste of $TiO_2$ nanoparticle. Analysis of titanium gel paste prepared at $150^{\circ}C$ shows that it has a pure anatase phase in XRD and mesoporous structure in SEM. The formation of the titanium gel 1-2 nm coated layer is confirmed by comparing the TEM image analysis of the titanium gel paste and the pristine paste. This coating layer improves the excited electron transfer and electrical contact between particles. The J-V curves of the organic binder DSSCs fabricated at $150^{\circ}C$ shows a current density of $0.12mA/cm^2$ and an open-circuit voltage of 0.47 V, while the titanium gel DSSCs improves electrical characteristics to $5.04mA/cm^2$ and 0.74 V. As a result, the photoelectric conversion efficiency of the organic binder DSSC prepared at low temperature is as low as 0.02 %, but the titanium gel paste DSSCs has a measured effciency of 2.76 %.

• Journal of The Korean Society of Emergency Medicine
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• v.29 no.6
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• pp.578-584
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• 2018

Objective: This study examined the initial partial pressure of carbon dioxide ($PCO_2$) as a possible indicator of prehospital ventilation and its association with prehospital i-gel in out-of-hospital cardiac arrest (OHCA) patients. Methods: The demographics and arrest parameters, including i-gel insertion and initial arterial blood gas analysis, of OHCA patients who visited the emergency department were analyzed retrospectively. Linear regression analysis was performed to examine the association between i-gel insertion and the initial $PCO_2$. Results: A total of 106 patients were investigated. Fifty-six patients had prehospital i-gel insertion and 50 patients did not have a prehospital advanced airway. The initial $PCO_2$ was higher in the i-gel group than the no advanced airway group (105.2 mmHg [77.5-134.9] vs. 87.5 mmHg [56.8-115.3], P=0.03). Prehospital i-gel insertion was associated with a higher initial $PCO_2$ level (${\beta}$ coefficient, 20.3; 95% confidence interval, 2.6-37.9; P=0.03). Conclusion: Prehospital insertion of i-gel was associated with higher initial $PCO_2$ values in OHCA patients compared to no advanced airway.

• Korean Journal of Plant Resources
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• v.10 no.3
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• pp.258-264
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• 1997

The introduction of molecular biology methodologies to plant improvement programs offers an invaluable opportunity for extensive germplasm characterization. We have applied the developed technique of random amplification of polymorphic DNA(RAPD)to the analysis of evaluating genetic diversity among Korean wild Codonopsis lanceolata. A total of 340 polymorpic hands were gernerated on agarose- and polyacrylamide-gel by 19 primers of abitrary sequence. grouped by cluster analysis using sample matching coefficients of similarity. Among of the samples. the minimum genetic distance value was obtained between sample no. 1(Girisan) and no. 2(Girisan), and the largest value between sample no. 11(Sulaksan) and no. 17(Sulaksan).In separate cluster dendrograms based on agareose - and polyacryamide-gel. some differences were observed; In the case of agarose gel,41 samples could be devided into 7 groups at below about 0.44 level of distance. However they were divided into 6 gourps at below about 0.40 level of distance in the case of polyacrylamide gel. These results showed that polymophic data in agrose were not grouped to wild plant selected from each mountainous district except for wild plants selected from Sulaksan and Chiaksan. We believe that polyacrylamide-RAPD is a superior method for detecting DNA polymorphism compared to agarose-RAPD method.

• Journal of the Korean Ceramic Society
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• v.25 no.2
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• pp.89-94
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• 1988

Alumina gel was prepared by the hydrolysis of aluminum isopropoxide Al(OC3H7i)3 at low temperature. Sample were calcined at the various temperatures for 10 houres in the electric furnace, respectively. In order to investigate the various propertis-thermal properties, pore size and distribution, and the transition of crystals, infrared spectroscopy, thermal analysis, particle size analysis, scanning electron microscopy, and porosimetry were employed. Transparent alumina gel was opalized at 1200$^{\circ}C$. Porosity was about 87% with pores below 0.7$\mu\textrm{m}$ and 55% at 1200$^{\circ}C$. The gel was transformed along the rising of temperature as follows; Boehmite\longrightarrow$\delta$-Al2O3\longrightarrow$\theta$\longrightarrowAl2O3\longrightarrow${\alpha}$-Al2O3.

• The Korean Journal of Food And Nutrition
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• v.21 no.2
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• pp.184-189
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• 2008

Soybean powder is a readily available ingredient that is consumed daily as a functional food material. Furthermore, red Ginseng is an herb with various physiological effects. Therefore, in this study, we examined the physiochemical characteristics of Soybean Dasik samples prepared with different amounts of added red Ginseng gel, including Hunter's color values, mechanical characteristics, and sensory qualities. The results of each analysis are as follows. For the soybean Dasik stored at room temperature($20^{\circ}C$), luminance was reduced as the amount of added red Ginseng gel increased. In addition, Hunter's a and b values were significantly higher in Dasik samples that did not contain red Ginseng gel, as compared to those with increasing red Ginseng gel content. The mechanical properties of the Dasik were also measured at room temperature showing significant differences between samples(p<0.001) for hardness, springiness, cohesiveness, gumminess, and chewiness. In the sensory evaluation, 3 rounds of testing indicated that sweetness acceptance scores were significantly reduced(p<0.001) as the amount of added red Ginseng gel in the Dasik increased. Finally, overall quality was significantly different between the samples(p<0.001) and acceptance scores increased with increasing red Ginseng gel content.

• Corrosion Science and Technology
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• v.20 no.4
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• pp.175-182
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• 2021

Magnesium alloy is limited in the industrial field because its standard electrode potential is -2.363 V vs. NHE (Normal Hydrogen Electrode) at 25 ℃. This high electrochemical activity causes magnesium to quickly corrode with oxygen in air; chemical conversion coating prevents corrosion but causes surface defects like cracks and pores. We have examined the anti-corrosion effect of sol-gel coating sealed on the defected conversion coating layer. Sol-gel coatings produced higher voltage current and smaller pore than the chemical conversion coating layer. The conversion coating on magnesium alloy AZ31 was prepared using phosphate-permanganate solution. The sol-gel coating was designed using trimethoxymethylsilane (MTMS) and (3-Glycidyloxypropyl) trimethoxysilane (GPTMS) as precursors, and aluminum acetylacetonate as a ring-opening agent. The thermal shock resistance was tested by exposing specimens at 140 ℃ in a convection oven; the results showed changes in the magnesium alloy AZ31 surface, such as oxidization and cracking. Scanning electron microscope (FE-SEM) analysis confirmed a sealed sol-gel coating layer on magnesium alloy AZ31. Electrochemical impedance spectroscopy (EIS) measured the differences in corrosion protection properties by sol-gel and conversion coatings in 0.35 wt% NaCl solution, and the potentiodynamic polarization test and confirmed conversion coating with the sol-gel coating show significantly improved resistance by crack sealing.

• Journal of Periodontal and Implant Science
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• v.53 no.5
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• pp.321-335
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• 2023

Purpose: The aim of this study was to investigate the efficacy of photo-crosslinked gelatin methacryloyl (GelMa) hydrogel containing calcium phosphate nanoparticles (CNp) when applying different fabrication methods for bone regeneration. Methods: Four circular defects were created in the calvaria of 10 rabbits. Each defect was randomly allocated to the following study groups: 1) the sham control group, 2) the GelMa group (defect filled with crosslinked GelMa hydrogel), 3) the CNp-GelMa group (GelMa hydrogel crosslinked with nanoparticles), and 4) the CNp+GelMa group (crosslinked GelMa loaded with nanoparticles). At 2, 4, and 8 weeks, samples were harvested, and histological and micro-computed tomography analyses were performed. Results: Histomorphometric analysis showed that the CNp-GelMa and CNp+GelMa groups at 2 weeks had significantly greater total augmented areas than the control group (P<0.05). The greatest new bone area was observed in the CNp-GelMa group, but without statistical significance (P>0.05). Crosslinked GelMa hydrogel with nanoparticles exhibited good biocompatibility with a minimal inflammatory reaction. Conclusions: There was no difference in the efficacy of bone regeneration according to the synthesized method of photo-crosslinked GelMa hydrogel with nanoparticles. However, these materials could remain within a bone defect up to 2 weeks and showed good biocompatibility with little inflammatory response. Further improvement in mechanical properties and resistance to enzymatic degradation would be needed for the clinical application.