• Restorative Dentistry and Endodontics
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• v.30 no.2
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• pp.112-120
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• 2005

This study was done to evaluate whether there were any differences in microleakage of class V composite restorations according to restoration site and cavity size. Total sixty-four restorations were made in molar teeth using Esthet-X. Small ($2\;{\times}\;2\;{\times}\;1.5\;mm$) and large ($4{\times}2{\times}1.5\;mm$) restorations were made at the buccal/lingual surface and the proximal surface each. After 1,000 times of thermocycling ($5^{\circ}\;-\;55^{\circ}C$), resin replica was made and the percentage of marginal gap to the whole periphery of the restoration was estimated from SEM evaluation. Thermocycled tooth was dye penetrated with $50\%$ silver nitrate solution. After imbedding in an auto-curing resin, it was serially ground with a thickness of 0.25 mm. Volumetric microleakage was estimated after reconstructing three dimensionally. Two-way ANOVA and independent T-test for dye volume, Mann-Whitney U test for the percentage of marginal gap, Spearman's rho test for the relationship between two techniques were used, The results were as follows : 1. The site and size of the restoration affected on the microleakage of restoration. Namely, much more leakage was seen in the proximal and the large restorations rather than the buccal/lingual and the small restorations. 2. Close relationship was found between two techniques (Correlation coefficient = 0.614/ P = 0.000). Within the limits of this study, it was noted that proximal and the large restorations leaked more than buccal/lingual and the small restorations. Therefore, it should be strictly recommended large exposure of margins should be avoided by reducing unnecessary tooth reduction.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.5
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• pp.375-395
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• 2006

Purpose: Lingual nerve (LN) damage may be caused by either tumor resection or injury such as wisdom tooth extraction, Although autologous nerve graft is sometimes used to repair the damaged nerve, it has the disadvantage of necessity of another operation for nerve harvesting. Moreover, the results of nerve grafting is not satisfactory. The nerve growth factor (NGF) is well-known to play a critical role in peripheral nerve regeneration and its local delivery to the injured nerve has been continuously tried to enhance nerve regeneration. However, its application has limitations like repeated administration due to short half life of 30 minutes and an in vivo delivery model must allow for direct and local delivery. The aim of this study was to construct a well-functioning $rhNGF-{\beta}$ adenovirus for the ultimate development of improved method to promote peripheral nerve regeneration with enhanced and extended secretion of hNGF from the injured nerve by injecting $rhNGF-{\beta}$ gene directly into crush-injured LN in rat model. Materials and Methods: $hNGF-{\beta}$ gene was prepared from fetal brain cDNA library and cloned into E1/E3 deleted adenoviral vector which contains green fluorescence protein (GFP) gene as a reporter. After large scale production and purification of $rhNGF-{\beta}$ adenovirus, transfection efficiency and its expression at various cells (primary cultured Schwann cells, HEK293 cells, Schwann cell lines, NIH3T3 and CRH cells) were evaluated by fluorescent microscopy, RT-PCR, ELISA, immunocytochemistry. Furthermore, the function of rhNGF-beta, which was secreted from various cells infected with $rhNGF-{\beta}$ adenovirus, was evaluated using neuritogenesis of PC-12 cells. For in vivo evaluation of efficacy of $rhNGF-{\beta}$ adenovirus, the LNs of 8-week old rats were exposed and crush-injured with a small hemostat for 10 seconds. After the injury, $rhNGF-{\beta}$ adenovirus($2{\mu}l,\;1.5{\times}10^{11}pfu$) or saline was administered into the crushed site in the experimental (n=24) and the control group (n=24), respectively. Sham operation of another group of rats (n=9) was performed without administration of either saline or adenovirus. The taste recovery and the change of fungiform papilla were studied at 1, 2, 3 and 4 weeks. Each of the 6 animals was tested with different solutions (0.1M NaCl, 0.1M sucrose, 0.01M QHCl, or 0.01M HCl) by two-bottle test paradigm and the number of papilla was counted using SEM picture of tongue dorsum. LN was explored at the same interval as taste study and evaluated electro-physiologically (peak voltage and nerve conduction velocity) and histomorphometrically (axon count, myelin thickness). Results: The recombinant adenovirus vector carrying $rhNGF-{\beta}$ was constructed and confirmed by restriction endonuclease analysis and DNA sequence analysis. GFP expression was observed in 90% of $rhNGF-{\beta}$ adenovirus infected cells compared with uninfected cells. Total mRNA isolated from $rhNGF-{\beta}$ adenovirus infected cells showed strong RT-PCR band, however uninfected or LacZ recombinant adenovirus infected cells did not. NGF quantification by ELISA showed a maximal release of $18865.4{\pm}310.9pg/ml$ NGF at the 4th day and stably continued till 14 days by $rhNGF-{\beta}$ adenovirus infected Schwann cells. PC-12 cells exposed to media with $rhNGF-{\beta}$ adenovirus infected Schwann cell revealed at the same level of neurite-extension as the commercial NGF did. $rhNGF-{\beta}$ adenovirus injected experimental groups in comparison to the control group exhibited different taste preference ratio. Salty, sweet and sour taste preference ratio were significantly different after 2 weeks from the beginning of the experiment, which were similar to the sham group, but not to the control group.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.1
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• pp.60-67
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• 2010

Although several studies have reported that Cr, Cu and As can leach from CCA-treated woods, few studies have been conducted on this topic in Korea. Therefore, this study was conducted to monitor Cr, Cu and As leaching from CCA-treated wood products and to develop a rapid identification method for CCA-treated wood products by using indicators such as PAN stain. Soil samples were collected at depths of 0-70 cm and wood samples were collected by thickness of wood layer. The soil and wood samples were then digested and analyzed for Cr, Cu and As concentrations using an atomic absorption spectrometer. The As and Cu concentrations decreased sharply with depth from 34.38 and 33.65 mg $kg^{-1}$ at 0-1 cm to 1.72 and 7.84 mg $kg^{-1}$ at 70 cm, respectively. In general, As was more mobile than Cr and Cu in the soil. For wood samples, the Cr, Cu and As concentrations were higher in the outer layer (0-0.5cm) than the inner layers (0.6-4.5cm). Evaluation of rapid identification methods revealed that 100% acetone with 0.1% PAN indicator was the best combination for detection of CCA-treated wood in the field.

• Journal of radiological science and technology
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• v.26 no.4
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• pp.39-46
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• 2003

Digital radiographic systems based on solid-state detectors, commonly referred to as flat-panel detectors, are gaining popularity in clinical practice. Large area, flat panel solid state detectors are being investigated for digital radiography. The purpose of this work was to evaluate the active matrix flat panel digital x-ray detectors in terms of their modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE). In this paper, development and evaluation of a selenium-based flat-panel digital x-ray detector are described. The prototype detector has a pixel pitch of $139\;{\mu}m$ and a total active imaging area of $14{\times}8.5\;inch^2$, giving a total 3.9 million pixels. This detector include a x-ray imaging layer of amorphous selenium as a photoconductor which is evaporated in vacuum state on a TFT flat panel, to make signals in proportion to incident x-ray. The film thickness was about $500\;{\mu}m$. To evaluate the imaging performance of the digital radiography(DR) system developed in our group, sensitivity, linearity, the modulation transfer function(MTF), noise power spectrum (NPS) and detective quantum efficiency(DQE) of detector was measured. The measured sensitivity was $4.16{\times}10^6\;ehp/pixel{\cdot}mR$ at the bias field of $10\;V/{\mu}m$ : The beam condition was 41.9\;KeV. Measured MTF at 2.5\;lp/mm was 52%, and the DQE at 1.5\;lp/mm was 75%. And the excellent linearity was showed where the coefficient of determination ($r^2$) is 0.9693.

• Journal of the Korean Society for Nondestructive Testing
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• v.26 no.4
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• pp.211-219
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• 2006

The UET(ultrasound excited thermography) for the ,eat-time diagnostics of the object employs an infrared camera to image defects of the surface and subsurface which are locally heated using high-frequency putted ultrasonic excitation. The dissipation of high-power ultrasonic energy around the feces of the defects causes an increase In temperature. The defect's image appears as a hot spot (bright IR source) within a dark background field. The UET for nondestructive diagnostic and evaluation is based on the image analysis of the hot spot as a local response to ultrasonic excited heat deposition. In this paper the applicability of VET for fast imaging of defect is described. The ultrasonic energy is injected into the sample through a transducer in the vertical and horizontal directions respectively. The voltage applied to the transducer is measured by digital oscilloscope, and the waveform are compared. Measurements were performed on four kinds of materials: SUS fatigue crack specimen(thickness 14mm), PCB plate(1.8 mm), CFRP plate(3 mm) and Inconel 600 plate (1 mm). A high power ultrasonic energy with pulse durations of 250ms Is injected into the samples in the horizontal and vertical directions respectively The obtained experimental result reveals that the dissipation loss of the ultrasonic energy In the vertical injection is less than that in the horizontal direction. In the cafe or PCB, CFRP, the size of hot spot in the vortical injection if larger than that in horizontal direction. Duration time of the hot spot in the vertical direction is three times as long as that in the horizontal direction. In the case of Inconel 600 plate and SUS sample, the hot spot in the horizontal injection was detected faster than that in the vertical direction

• Food Science of Animal Resources
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• v.30 no.3
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• pp.495-503
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• 2010

Analyses were conducted to estimate the effect of quality grade on the carcass characteristics, physico-chemical and sensory traits of Longissimus dorsi in Hanwoo. A total of 42,113 carcasses were selected on the basis of five quality grades (grade $1^{++}$, $1^+$, 1, 2, and 3) and an additional 258 samples of Longissimus dorsi were used to evaluate the beef quality. The increase in quality grade from grade 3 to grade $1^{++}$ was significant (p<0.05) for carcass weight (from 338.7 kg to 387.2 kg), backfat thickness (from 7.45 mm to 12.23 mm) and marbling score (from 1.09 to 8.31). In contrast, significantly decreased levels of meat color, fat color, texture and maturity were apparent with increasing quality grade (p<0.05). Increasing quality grade was also correlated with significant increases (p<0.05) in crude fat contents (from 3.57% to 25.68%) and water holding capacity (from 52.41% to 58.03), and a decrease of the Warner-Bratzler shear force from 8.29 kg to 2.83 kg. The highest $L^*$ value (41.53) and highest cooking loss (22.11%) were observed with grade $1^{++}$ and 3 beef, respectively. There was no difference observed on $pH_{24}$ (5.53 to 5.66) among the quality grades, which were within the normal range. Sensory evaluation experiments revealed that quality grades were associated with significantly altered (all p<0.05) tenderness, juiciness, flavor, and overall acceptability. The crude fat contents showed significant correlation with juiciness (r=0.59), tenderness (r=0.71), flavor (r=0.55), and overall acceptability (r=0.69). The lower sensory trait scores were related to higher WBs. Grade $1^+$ Hanwoo beef had a significantly higher WBs and lower fat contents when compared to grade $1^{++}$ Hanwoo beef (p<0.05).

• Journal of agriculture & life science
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• v.46 no.1
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• pp.123-131
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• 2012

This study was conducted to estimate correlation structure between Hanwoo steer growth traits - body weights at 6 month, 12 month, 18 month and 24 month of age, average daily gain, carcass traits, body size traits at 18 months of age. Hanwoo progeny test data(body weight, body size traits) collected from 2004 to 2008 on a total of 1,838 steers at Hanwoo Improvement Main Center(NACF) were analyzed. Carcass traits were used to score the 24 months of age and slaughter. Correlation analyses were performed with observed scales of the traits and with residuals considering fixed effects in generalized linear models. The correlated coefficient estimated between live weight at slaughter(24 months of age) and cold carcass weight was high at 0.92. Correlation between beef yield index values and backfat thickness was estimated to be high and negative at -0.92. Hip height and wither height was found to be highly correlated(0.89). Chest width and chest depth also was found to be highly correlated at 0.73. Rump width was highly correlated with chest depth(0.75) and chest width(0.74). Correlation between pelvic width and rump width was estimated to be 0.74. Hipbone width was shown to be highly correlated with chest depth(0.73), chest width(0.70), rump width(0.75), or pelvic width(0.75). Correlation between wither height and carcass weight was 0.48 in observed scale. Chest girth was phenotyically (residual correlation) correlated with carcass weight (0.51), the estimates of which were some higher than than with the other carcass traits. This study will be utilized for Hanwoo Steers genetic evaluation.

• Korean Journal of Plant Taxonomy
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• v.32 no.3
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• pp.339-362
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• 2002

Pollen morphology of 13 species of Korean Euphorbia was re-examined by means of LM and SEM. Taxonomic evaluation of palynological characters and relationships among taxa were also discussed based on the analysis of polar length, equatorial diameter, aperture size and exine thickness. Korean Euphorbia species were classified into three groups based on the mean size of polar length (P) and equatorial diameter (E) as follows:Group 1. sect. Tulocarpa and Tithymalus of subgenus Esula; $(P){\times}(E)=(54.88-67.17{\mu}m){\times}(44.30-64.75{\mu}m)$, Group 2. sect. Esula and Helioscpiae of subgenus Esula; $(P){\times}(E)=(39.98-47.24{\mu}m){\times}(36.07-38.83{\mu}m)$, Group 3. sect. Chamaesyce and Hypericifoliae of subgenus Chamaesyce; $(P){\times}(E)=(30.32-32.51{\mu}m){\times}(21.71-26.23{\mu}m)$. Various features of surface sculpturing were also grouped into 8 types by the characteristics of perporation size and distance of perporations as well as connection state of it. Pollen size and surface sculpturing were comparatively available in the levels of subgenus and section. Especially subgenus Chamaesyce was distinctly different from subgenus Esula by having compactly distributed perporations on exine surface as well as its small size of pollen grains. Because of the great variations in pollen size and the occurrence of various types of surface sculpturing according to the local poulations of each species, it was evaluated that they were unsuitable in classifying each species of Euphorbia. But such cases, that is, E. hylonoma being more familiar with E. ebracteolata than E. Pallasii, and E. pekinensis and E. fauriei as well as E. pallasii being strongly related with each other based on the similarity of surface sculpturing, reflected its usefulness in the classification of some Euphorbia species.

• Korean Journal of Heritage: History & Science
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• v.44 no.4
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• pp.142-153
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• 2011

'Silla Monument Stone in Jungseong-ri, Pohang' was discovered in Pohang City, Gyeongsangbuk Province of Korea in 2009. The monument stone with irregular shape has dimensions of maximum height of 105cm, width of 47.6~49.6cm, thickness of 13.8~14.7cm and weight of 115kg. The results of monument stone was found to be granitite. Conservation treatment procedure was carried out in the order of production of Weathering map, cleaning of surface pollutants, consolidation using ethyl silicate. Black pollutant(crust) that covered more than 60% of the surface was analyzed first in order to remove the pollutants on the surface of the monumental stone by cleaning of surface pollutants using laser. The purpose on analysis was not only to verify the pollutants on the stone but also to carry out preliminary cleaning by securing rocks with same pollutant as the monumental stone. As the results of analysis using p-XRF(PMI. INNOV-X, USA) on the site, high level of Mn and Fe were detected, and the analysis of small section that had been fallen off with SEM/EDX for the purpose of quantitative analysis also detected high level of Mn. The Similar contaminants on Stone secured in the manner described above were made into 10 samples ($5cm{\times}5cm$) and was subjected to preliminary cleaning by Nd-YAG Laser(Laser&Physics, Korea). The results of surface observation through portable microscope during cleaning revealed that the power of 460mJ, wavelength of 1064nm and irradiation frequency of 1,800~2,300 per $25cm^2$ were most effective. Evaluation on the preservative treatment was made through confirmation of the extent of removal through color-difference meter measurement and component analysis prior to and following removal of the pollutants. As the result of color-difference meter measurement increase in the brightness was evidenced by the increase in the brightness ($L^*$)value from 33 to 49, and it was possible to ascertain the reduction in the pollutants as the content of Mn was reduced by about 80% from $50,000{\pm}5,000ppm$ to $10,000{\pm}2,000pmm$ from the result of component analysis.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.3
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• pp.211-218
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• 2019

Purpose: The purpose of the present study was to compare the accuracy of four different metal copings fabricated by CAD/CAM technology and to evaluate clinical effectiveness. Materials and methods: Composite resin tooth of the maxillary central incisor was prepared for a metal ceramic crown and duplicated metal die was fabricated. Then scan the metal die for 12 times to obtain STL files using a confocal microscopy type oral scanner. Metal copings with a thickness of 0.5 mm and a cement space of $50{\mu}m$ were designed on a CAD program. The Co-Cr metal copings were fabricated by the following four methods: Wax pattern milling & Casting (WM), Resin pattern 3D Printing & casting (RP), Milling & Sintering (MS), Selective laser melting (SLM). Silicone replica technique was used to measure marginal and internal discrepancies. The data was statistically analyzed with One-way analysis of variance and appropriate post hoc test (Scheffe test) (${\alpha}=.05$). Results: Mean marginal discrepancy was significantly smaller in the Group WM ($27.66{\pm}9.85{\mu}m$) and Group MS ($28.88{\pm}10.13{\mu}m$) than in the Group RP ($38.09{\pm}11.14{\mu}m$). Mean cervical discrepancy was significantly smaller in the Group MS than in the Group RP. Mean axial discrepancy was significantly smaller in the Group WM and Group MS then in the Group RP and Group SLM. Mean incisal discrepancies was significantly smaller in the Group RP than in all other groups. Conclusion: The marginal and axial discrepancies of the Co-Cr coping fabricated by the Wax pattern milling and Milling/Sintering method were better than those of the other groups. The marginal, cervical and axial fit of Co-Cr copings in all groups are within a clinically acceptable range.