• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.1
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• pp.122-129
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• 2007

The purpose of this study was to evaluate the effects of a various light curing time on the residual monomers released from light-cured dental sealant, and to examine the effectiveness of surface treatment in reducing the oxygen-inhibited layer of light-cured dental sealant($Helioseal^{(R)}$ F, Vivadent, Liechtenstein). Specimens were cured with a halogen light curing unit(XL 3000, 3M, USA) for 20, 40, 60s. Surface treatment of a light-cured dental sealant included no treatment(control group), a 10-seconds exposure to distilled water(Group I), 10-seconds manual application using a cotton pellet wetted with 75% alcohol(Group II), and 10-seconds application of a water/pumice slurry using a rubber cup on a slow-speed handpiece The specimens were eluted in distilled water for 10 minutes. All elutes were analyzed by HPLC for identification and quantitive analysis of monomers. The results of this study can be summarized as follows. 1. None of the chromatograms of the tested sealant displayed peaks with the same retention time as that of the standard solution, except for TEGDMA. 2. The release of TEGDMA decreased with increasing curing time in conventional halogen light. 3. All surface treatment group had a decrease of monomer release in comparison with no treatment group. 4. Treatment that Group III eliminated the greatest amount of any type of residual monomers. 5. The elution of unreacted monomers from curing with halogen curing unit for 60s and Group III was less than other groups.

• Korean Journal of Veterinary Research
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• v.34 no.3
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• pp.487-492
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• 1994

The study was conducted to investigate the phenotypes of blood proteins, hemoglobin and albumin, of 104 German shepherds in Dag-gu, Yae-chum Kim-hae and Kwang-ju area by the starch gel electrophoresis. The results obtained were summarized as follows: 1. The hemoglobin phenotypes were observed three(HbBB, HbBb and Hbbb). Fast migrating bands were same and slow migrating bands were divided by heavy(HbBB), light(HbBb) and non-stained(Hbbb). The frequencies of appearance in HbBB, HbBb and Hbbb were 17.31%, 51.92% and 30.77%, respectively. 2. The hemoglobin phenotypes were controlled by two allelic genes, $Hb^b$ and $Hb^B$. The gene frequencies were calculated at 0.567 in $Hb^B$ and 0.433 in $Hb^A$. 3. The albumin phenotypes were observed three(AlbFF, AlbSS and and AlbFS), which were divided by fast migrating band(AlbFF), slow migrating band(AlbSS) and mixed migrating band(AlbFS). The frequencies of appearance in AlbFF, AlbFS and AlbSS were 5.77%, 28.85% and 65.38%, respectively. 4. The albumin phenotypes were controlled by two alleic genes, $Alb^F$ and $Alb^S$. The gene frequencies were calculated at 0.202 in $Alb^F$ and 0.798 in $Alb^S$.

• Korean journal of food and cookery science
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• v.10 no.4
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• pp.405-411
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• 1994

This study was conducted to know the quality of chou made with flour pastes which were stored at different conditions of quick freezing, slow freezing, cold and room temperature. Also, this study included investigation of the chou properties such as expansion, sensory evaluation, degree of gelatinization, and physical and structural properties of paste were observed. There were not significant differences m diameter, height, volume, appearance, hollow formation, and sensory evaluation between the chou made with the paste stored at freezing condition and chou directly baked after pasting. Quick and slow freezing storages did not significantly affect the properties of chou, and the same results were obtained among the chou made with pastes thawed at room temperature and in microwave ovenrange. The chou of pastes stored at room temperature and in microwave ovenrange. The chou of pastes stored at room temperature and stored in refrigerator showed lowed expansion and value of sensory evaluation than those of frozen pastes. The paste stored at room temperature had the lowest hardness and viscosity compared with the other storage conditions. According to the observation of light microscope. the lipid bodies of the paste of freezing storage smaller those of the room temperature and refrigerator storage. The expantion of chou made with paste stored at room temperature was greatly decreased due to the high coalescence of lipid bodies, and also the paste components such as lipid, starch granule gluten at room temperature had inferior dispersion condition. The general tendency of the degree of gelatinization of chou were low in all treatments of paste. The values were 23.5%~46.0% in freezing, 77.3% in room temperature, 68.7% in directly baked after pasting, and 61.0% in cold storage, respectively. The formation and the taste of chou made with frozen paste were similar to those of chou directly baked pasting.

• Safety and Health at Work
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• v.2 no.3
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• pp.236-242
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• 2011

Objectives: To determine the feasibility of predicting static and dynamic peak back-compressive forces based on (1) static back compressive force values at the lift origin and destination and (2) lifting speed. Methods: Ten male subjects performed symmetric mid-sagittal floor-to-shoulder, floor-to-waist, and waist-to-shoulder lifts at three different speeds (slow, medium, and fast), and with two different loads (light and heavy). Two-dimensional kinematics and kinetics were captured. Linear regression analyses were used to develop prediction equations, the amount of predictability, and significance for static and dynamic peak back-compressive forces based on a static origin and destination average (SODA) backcompressive force. Results: Static and dynamic peak back-compressive forces were highly predicted by the SODA, with R2 values ranging from 0.830 to 0.947. Slopes were significantly different between slow and fast lifting speeds (p < 0.05) for the dynamic peak prediction equations. The slope of the regression line for static prediction was significantly greater than one with a significant positive intercept value. Conclusion: SODA under-predict both static and dynamic peak back-compressive force values. Peak values are highly predictable and could be readily determined using back-compressive force assessments at the origin and destination of a lifting task. This could be valuable for enhancing job design and analysis in the workplace and for large-scale studies where a full analysis of each lifting task is not feasible.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.21 no.3
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• pp.47-56
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• 2018

Research was initiated to investigate germination characteristics and germination pattern of 14 herbaceous plant entries used on the road slope during 30 days. An alternative germination condition for 14 herbaceous plant entries required by International Seed Testing Association(ISTA) was applied in the experiment, consisting of 8-hr light at $25^{\circ}C$ and 16-hr dark at $15^{\circ}C$. Significant differences were observed in the first germination rate(0.3%~40.7%)and in the final germination rate(7.7%~93.3%). Days to the first germination(2~8days), days to the 30% germination(2~6days) and days to the peak germination(6~18days) were different among 14 herbaceous plant entries in the study. From this result, we could find out higher final germination rate of 14 herbaceous plant entries in the following order; First, forage crops and cool-season turfgrasses; Second, herbeceous flowers; Third, wild plants. We could also divide germination rate among 14 herbaceous plant entries as 6 groups(I;very high, II;high, III;medium high, IV;medium low, V;low, VI;very low) based on the final germination rate and divide germination speed as 5 groups(A;very fast, B;fast, C;normal, D;slow, E;very slow)based on days to the peak germination. Considering germination characteristics and pattern of 14 herbaceous plant entries Medicago sativa, Lolium perenne, Festuca arundinacea and Cosmos sulphureus were regard as dominating species while Lespedeza cuneata, Silene armeria, Lotus corniculatus var.japonicus, Coreopsis tinctoria and Centaurea cyanus as competitive species following dominating species. However, Chrysanthemum burbankii, Pennisetum alopecuroides, Chrysanthemum boreale., Artemisia princeps var. orientalis and Arundinella hirta were not almost expected to emerge.

• Development and Reproduction
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• v.23 no.1
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• pp.35-42
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• 2019

Fish shows great difference in growth rate between individuals during larval development and early growth. This difference seriously reduces the production efficiency in fish culture. Growth hormone (GH)/Insulin-like growth factor 1 (IGF1) system is said to play some pivotal roles in fish growth. In this study, we investigated differences of GH, IGF1 and GHR gene expressions in juvenile red spotted grouper (Epinephelus akaara) with different growth performance. Red spotted groupers were reared under the same environmental condition (water temperature $24{\pm}1^{\circ}C$, natural light) for 96 days after hatching. They were divided into 3 groups by size (fast growing, middle growing and slow growing groups: FGG, MGG, and SGG, respectively). RNA was extracted from the brain, liver and muscle tissues from each group, and target gene expression was examined by real-time PCR. In the brain with pituitary gland, expression of GH gene in FGG was significantly higher than the expression in SGG, but the expression of IGF1 and GHR genes in the muscle was highest in SGG. Difference of GHR and IGF1 mRNA in the liver between groups with different growth performance was less clear than that in other tissues, although level of IGF1 mRNA was higher in SGG than in MGG. These results suggest that hormonal governing of growth is not the same in fast growing and slow growing fish, and size grading could cause a shift of hormonal state and growth pattern in this species.

• Animal Bioscience
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• v.34 no.10
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• pp.1684-1694
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• 2021

Objective: This study investigated the association between feed efficiency, physicochemical properties, flavor precursors and biomolecules in the thigh meat of Korat (KR) chickens. Methods: The feed intake and body weight of individual male KR chickens were recorded from 1 to 10 weeks old to calculate the individual residual feed intake (RFI) of 75 birds. At 10 weeks of age, chickens with the 10 highest (HRFI) and lowest RFI (LRFI) were slaughtered to provide thigh meat samples. The physicochemical properties (ultimate pH, water holding capacity [WHC], drip loss) and flavor precursors (guanosine monophosphate, inosine monophosphate (IMP), adenosine monophosphate and inosine) were analyzed conventionally, and Fourier transform infrared spectroscopy was used to identify the composition of biomolecules (lipids, ester lipids, amide I, amide II, amide III, and carbohydrates) and the secondary structure of the proteins. A group t-test was used to determine significant differences between mean values and principal component analysis to classify thigh meat samples into LRFI and HRFI KR chickens. Results: The physicochemical properties of thigh meat samples from LRFI and HRFI KR chickens were not significantly different but the IMP content, ratios of lipid, lipid ester, protein (amide I, amide II) were significantly different (p<0.05). The correlation loading results showed that the LRFI group was correlated with high ratios of lipids, lipid esters, collagen content (amide III) and beta sheet protein (rg loading >0.5) while the HRFI group was positively correlated with protein (amide I, amide II), alpha helix protein, IMP content, carbohydrate, ultimate pH and WHC (rg loading >0.5). Conclusion: The thigh meat from chickens with different RFI differed in physiochemical properties affecting meat texture, and in the contents of flavor precursors and biomolecules affecting the nutritional value of meat. This information can help animal breeders to make genetic improvements by taking more account of traits related to RFI.

• Tribology and Lubricants
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• v.2 no.2
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• pp.12-19
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• 1986

Using emulsion lubricant whose cooling effect and incombustibility are good and which is economical, I investigated lubricative mechanism and the behavior of scattered particles in the elastic fluid lubrication region with the line contact between rollers and plates and the light interference system. The results of the study are as follows: (1) The flow in the squeeze oil film is considered as comparatively wide clearance and narrow one, and in the former case the effect of the distribution of particles and the velocity on the flow. In the latter case, emulsion particles stay in the clearance an the oil film changes with the decrease of the oil film thickness. (2) In the wide clearance the velocity difference of the flow O/W or W/O emulsion is inverse proportional to the particle size. In the narrow clearance the distribution of the remained drops is different from one another and the scattered particles change more easily in O/W type than in W/O type. (3) At the beginning of the EHL the stagnation region with slow flowing velocity exists and the behavior at the region is different depending on the particle size. (4) By observing the dischromatic light interference line, emulsion oil passing through EHL region and the crack behavior at the beginning of EHL were found.

• Journal of Astronomy and Space Sciences
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• v.32 no.2
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• pp.121-125
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• 2015

At the suggestion of the NASA Meteoroid Environment Office (NASA/MEO), which promotes lunar impact monitoring worldwide during NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) mission period (launched Sept. 2013), we set up a video observation system for lunar impact flashes using a 16-inch educational telescope at Chungnam National University. From Oct. 2013 through Apr. 2014, we recorded 80 hours of video observation of the unilluminated part of the crescent moon in the evening hours. We found a plausible candidate impact flash on Feb. 3, 2014 at selenographic longitude $2.1^{\circ}$ and latitude $25.4^{\circ}$. The flash lasted for 0.2 s and the light curve was asymmetric with a slow decrease after a peak brightness of $8.7{\pm}0.3mag$. Based on a star-like distribution of pixel brightness and asymmetric light curve, we conclude that the observed flash was due to a meteoroid impact on the lunar surface. Since unequivocal detection of an impact flash requires simultaneous observation from at least two sites, we strongly recommend that other institutes and universities in Korea set up similar inexpensive monitoring systems involving educational or amateur telescopes, and that they collaborate in the near future.

• Journal of the Korea Institute of Building Construction
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• v.12 no.3
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• pp.323-331
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• 2012

Since the 1970s, the mechanical properties of concrete at high temperature, such as compressive strength, elastic modulus, thermal strain, etc. have been investigated. Internal and external factors should be effect to concrete elevated temperature. In particular, the thermal properties of aggregate and cooling conditions are most important to estimate residual mechanical properties. This study evaluates the mechanical properties of concrete with aggregate type and cooling methods. We use normal and light aggregate for different thermal properties, and also test mechanical properties to use ${\O}100{\times}200$ mm cylinder specimen according to target temperature, slow cooling and water cooling. We found that normal aggregate concrete that uses is more highly influenced by cooling conditions than concrete that uses light aggregate concrete. In addition, the residual mechanical properties of concrete increase as cooling velocity lowers.