• Applied Microscopy
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• v.41 no.1
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• pp.1-11
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• 2011

This experiment was performed to evaluate the morphological responses of the gastric epithelial cells of the mouse, inoculated with Ehrlich carcinoma cells in the inguinal area, following administration of 5-fluorouracil, mitomycin C or Acriflavine-Guanosine compound (AG60). In this study, each mouse was inoculated with $1{\times}10^7$ Ehrlich carcinoma cells subcutaneously in the inguinal area. From next day after inoculations, 0.2 mL of saline, 5-fluorouracil (30 mg/kg), mitomycin C ($400{\mu}g/kg$) or AG60 (30 mg/kg) were injected to the animals every other day, respectively. Each animals were sacrificed after 7th injection and tissue were taken from the gastric mucosa. Thereafter, the ultrathin sections were stained with uranyl acetate and lead citrate. In the 5-fluorouracil-, mitomycin C- or AG60-treated mice, myelin figures and multivesicular bodies within the gastric mucous epithelial cells were observed more frequently than those of the normal control. In the 5-fluorouracil-treated mice, membrane structures containing a few mucous granules in the luminal space were observed. Indeed, bulging cytoplasmic process containing mucous granules protruding into the gastric lumen were observed in the mitomycin Ctreated mice. Therefore, this study suggested that AG60 as compared with 5-fluorourail and mitomycin C may effective medicine without damage to the secretion ability of gastric mucous epithelial cells.

• The korean journal of orthodontics
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• v.27 no.5 s.64
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• pp.771-779
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• 1997

The purpose of this in vitro study was to evaluate the effects of different acid etching times on the enamel surface morphology, shear bond strength and debonding failure mode of orthodontic attachment. Ninety six extracted human mandibular premolars were divided into eight groups of twelve teeth. The buccal surfaces were etched with $37\%$, phosphoric acid for 5, 10, 15, 30, 45, 60, 90 and 120 seconds, respectively. Two teeth from each group were used for scanning electron microscope examination. On the etched buccal surfaces of remaining teeth, orthodontic attachments(lingual buttons) were bonded with light cured orthodontic adhesive. Twenty foot hours after bonding, a Instron universal testing machine was used to determine shear bond strength of orthodontic attachment to enamel. After debonding, bases of orthodontic attachments and enamel surfaces were examined under stereoscopic microscope to determine failure mode. Statistical analysis of the data was carried out with one nay ANOVA and Duncan's multiple range test The results were as follows; 1. There was no statistically significant difference in shear bond strengths between the various etching times(p<0.05). 2. The failure modes of orthodontic attachments had some differences. In 5, 10 and 15 seconds etching groups, the percentage of adhesive/enamel interface failure was higher than that of adhesive/attachment interface failure. On the contrary, in 30, 45, 60, 90 and 120 seconds etching groups, the results were reversed. 3. The etching patterns of enamel surfaces had a great variation. So, we could not find any correlation between etching pattern and bond strength. 4. The findings in this study indicate that in vitro reduction of the etching me to 5 seconds maintains clinically acceptable bond strength. However, further study is required to determine the cause of failure mode in 5, 10 and 15 seconds groups.

• Journal of Soil and Groundwater Environment
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• v.13 no.1
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• pp.13-23
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• 2008

The triaxial compression tests and consolidation tests using NaCl solution and leachates as substitute pore (or saturated) water in samples were carried out to find out the behavior characteristics of strength, deformation and permeability coefficient of contaminated clay. Also, the chemical property analysis on the clay samples using scanning electron microscope and energy dispersive x-ray spectrometer were involved. The magnitudes of composition ratio were shown in the order of O, C, Si, Al, and Fe as a result of chemical composition analysis for clay samples. Besides, as the results of triaxial compression tests and consolidation tests, the shear strength, compression and permeability properties were increased with increasing in the concentration of contaminant (NaCl). It may be considered that these circumstances be caused by the changes of soil structure to flocculent structure due to the decrease in the thickness of diffuse double layer with increasing in the concentration of electrolyte. MT3D model was also using to grasp the procedures that the groundwater may be contaminated by the leachates permeated through the clay liner. The results of contaminant transport analysis showed a tendency that the predicted concentration of groundwater was higher with increasing in the initial concentration of $Cl^-$ ion and increased as a nonlinear curves with time. The transportation distance calculated by the use of regression equation between the distance from contaminant source and the concentration of $Cl^-$ ion was increased with increasing the initial concentration.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.4
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• pp.313-321
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• 2005

To know the pollution level concerning the microbes contamination condition in soft contact lenses, 2 experiments were operated with different methods. Firs experiment, we observed lenses surfaces through a scanning electronic microscope after pollution sort contact lenses with the suspensions of Staphylococcus aureus, Pseudomonas aeruginosa and Entrobacter aerogenes which can be major bacteria causing keratitis as wearing on soft contact lenses. As 1 hour after pollution with the soft contact lenses, we observed that many bacteria adhered to the lenses, and the pollution condition got worse with passing time increase(2, 4, 6, 12, and 24 hours, respectively). At 12 hours lapse of polluting soft contact lenses with P. aeruginosa, some bacteria adhered to the lenses. And as 24 hours lapsed after pollution soft lenses with E. aerogenes, bacteria adhered to them, and atypical substance was observed some of the surface of lenses. Second experiment, we observed the microbe pollution condition in soft contact lenses by let 21 people in twenties(men & women), who doesn't eye disorders, wear soft contact lenses during 4 hours. As the result, many kinds of bacterium and fungus were observed, and especially, the bacteria could be identified with their colors and the shapes of colony, so we found that single type, two types, and three types of bacteria adhered to their lenses.

• Conservation Science in Museum
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• v.1
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• pp.61-74
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• 1999

Elemental analysis of 40 glass samples from the Northern Tomb and the Southern Tomb of Hwangnam-daech'ong No. 98 was performed. Fourteen compositions of each sample were analyzed quantitatively by SEM-EDS and glass samples were classified by multivariate analysis such as PCA. All of 40 samples were confirmed to be Na₂O-CaO-SiO₂ system with about 20% of Na₂O. Samples were classified into two groups by doing PCA on concentrations of 5 major elements(SiO₂, Al₂O₃, Na₂O, CaO and K₂O). Samples included in group I showed the concentration of Al₂O₃ is about 9.7% and that of CaO, about 2.2%. In group II, concentration of Al₂O₃ is about 3.2% and that of CaO, about 4.9%. Especially yellow grains embedded in sample No. 12 were shown to be PbSnO₃ by micro XRD, which was the first coloring material ever found in Korea. Lead isotope ratios of samples No. 12 and No. 17 which contained lead were measured by TIMS. The origin of lead was traced by means of multivariate analysis such as SLDA. The result showed that lead from southern China and southern Korea had been used for making glass.

• Polymer(Korea)
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• v.29 no.3
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• pp.282-287
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• 2005

A novel ice particle leaching method for fabrication of porous and biodegradable PLGA scaffold has been proposed for the application to tissue engineering. After uniform mixing of poly(L-lactide-co-glycolide) (PLGA) and bovine serum albumin-fluorescein isothiocyanate (FITC-BSA), the FITC-BSA loaded scaffold was fabricated by adding various ratio of ice particle. The release profiles of FITC-BSA were examined using pH 7.4 PBS for 28 days at $37^{circ}$. The release amount was determined by fluorescence intensity by using the fluorescence spectrophotometer and the morphological change of the scaffolds was observed by scanning electron microscope. The release initial burst of BSA containing scaffolds was lower than that of simple dipping scaffolds resulting in constant release aspect. Although the BSA concentration increased. the initial burst was not increased. As a result of this study, it can be suggested that ice particle leaching method for the tissue engineered scaffold miff be very useful and it is possible to impregnate with water soluble factors like cytokine. We suggest that ice particle leaching method may be useful to tissue engineered organ regeneration.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.1
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• pp.55-60
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• 2010

Purpose: We investigated the changes of plastic lens after etching of coating films by comparing uncoated lens. Methods: CR-39, middle index and high index lenses of 0 (zero) diopter were etched at $80^{\circ}C$ and room temperature using a coating remover, and then changes of refractive power, transmittance and surface morphology were investigated. Results: There were no differences in refractive power and transmittance between uncoated and etched lenses. The etching rate was similar in both CR-39 and middle index lens, but in the case of high index lens, it was slower and less steady than the others. From the SEM observation of lens surface, etching damage was found out on the surface of etched lens. It was shown the least damage in middle index lens but the most damage in high index lens. Conclusions: If the etching of coating films is demanded on condition that the surface of ophthalmic lenses are not damaged, a using of most adequate coating remover based on lens material should be considered, and a caution for proper etching conditions is required.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.11 no.4
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• pp.259-269
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• 2013

Applicability of ammonium molybdophosphate/iron oxides-polyacrylonitrile (AMP/IO-PAN) composites on the removal of radionuclides in the radioactive wastewater generated from nuclear power plants was investigated. The composites were characterized using the following analytical techniques: X-ray diffraction (XRD), Fourior transform-infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), particle size analyzer (PSA), nitrogen adsorption-desorption and magnetic property measurement system (MPMS). 10wt% of AMP/IO-PAN composite has a saturation magnetization of 2.038 emu/g. Single-solute sorptions of Co, Sr and Cs onto 10wt% of AMP/IO-PAN composite were investigated. The maximum sorption capacities ($Q^0$) predicted by the Langmuir model on 10wt% of AMP/IO-PAN composite were 0.097, 0.086 and 0.66 mmol/g for Co, Sr and Cs, respectively. The maximum sorption capacities ($Q^0$) of Cs predicted by Langmuir model on 0, 10, 20 and 30wt% of AMP/IO-PAN composites were 0.702, 0.655, 0.602 and 0.559 mmol/g, respectively. The maximum sorption capacities ($Q^0$) of Cs decreased with increasing the iron oxide content in the AMP/IO-PAN composites.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.11
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• pp.649-655
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• 2015

As a novel water treatment membrane, concept of ceramic-based graphene membrane (CbGM) was suggested, and its mass transport behavior was investigated. The selectivity of CbGM was given by graphene material which is consisting of active layer, only transmitting water, but rejecting salts. Filtration-assisted assembly methods was employed as a facile method to fabricate CbGM. Surface morphology and characteristics of CbGM were analyzed by scanning electron microscopy (SEM) and contact angle. In addition, three different kinds of solutes (i.e., NaCl, $MgCl_2$, $Na_2SO_4$) were tested in batch forward osmosis system to confirm the mass transport behavior. Through surface morphology analysis and mass transport behavior, it was revealed that interlocking between graphene layers is very important, rather than thickness of laminated graphene layers, in terms of selectivity to CbGM. All the anions in each solute showed faster transport than those of cations. In addition, solutes which have high ion valence charge ratio of anion to cation ($Z^-/Z^+$) was easier to be passed through CbGM. It indirectly implied that the surface charge of CbGM appear to be positive. In addition, It showed that surface charge of CbGM has a great role on mass transport, in particular, transport of matter having charges, generally ions.

• Journal of Forest and Environmental Science
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• v.23 no.1
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• pp.57-63
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• 2007

Anatomical characteristics of black and white charcoal of Quercus variabilis and Quercus mongolica manufactured by a Korean traditional kiln were investigated by scanning electron microscopy. In both charcoal, the earlywood vessels shrank in tangential direction, whereas the other cells didn't change. However, in the case of latewood vessels, black charcoal did not show tangential direction shrinkage, but white charcoal did. The wood fiber were changed severly in shape due to the excessive shrinkage. Tyloses in early wood vessel were still shown unchanged shape in both charcoals. Cell wall of ray parenchyma was observed and their shapes were severly distorted. Voids between ray parenchyma were observed in white charcoal, which maybe due to high temperature in white charcoal. Moreover, lumen diameters in the uniseriate ray and multiseriate ray were decreased at the high charring temperature. These results showed that the low charcoal yield of the white charcoal compared to the black charcoal was caused by decrease of cell dimensions as well as loss of wood components associated with the carbonization temperature.