• The Journal of Korean Academy of Prosthodontics
• /
• v.41 no.4
• /
• pp.476-492
• /
• 2003

Purpose : The purpose of this study was to compare HEMA and TEGDMA as diluents for the composite resin. Material and methods : Eight kinds of experimental light curable composite resins were prepared and used. Concentrations of monomer and filler were same for all experimental composites, except, the diluent's ratios to the monomer. The ratio of diluents to Bis-GMA were 15%, 20%, 25%, and 30%, and two kinds of diluents were used, so total experimental groups were eight including one control group of 25% TEGDMA. Results : Depth of cure, flexural strength, shear bond strength to bovine enamel, shear bond strength to bovine dentin, water absorption and solubility of composites in water were measured. Sample size for each groups were 10. Arithmetic means were used as each groups representative values, and regression test for two diluents and low concentrations, Duncan's multiple range test, and Two-way ANOVA test were done for kinds of diluents and its concentrations at level of 0.05. Conclusion : Following results were obtained ; 1. There were not significant differences in effects of HEMA and TEGDMA to depth of cure, flexural strength of composites and shear bond strength to bovine enamel (p>0.05). 2. Increase of the concentrations of the diluents made the depth of cure (p<0.001) and flexural strength (p<0.05) a little higher. 3. Shear bond strength to dentin was higher on HEMA containing composites than TEGDMA containing composites (p<0.001). 4. Water absorption was higher on HEMA containing composites than TEGDMA containing composites (p<0.01).

• The Plant Pathology Journal
• /
• v.30 no.4
• /
• pp.384-396
• /
• 2014

Vegetative compatibility groups (VCGs) are determined for many fungi to test for the ability of fungal isolates to undergo heterokaryon formation. In several fungal plant pathogens, isolates belonging to a VCG have been shown to share significantly higher genetic similarity than those of different VCGs. In this study we sought to examine the relationship between VCG and genetic similarity of an important cool season turfgrass pathogen, Sclerotinia homoeocarpa. Twenty-two S. homoeocarpa isolates from the Midwest and Eastern US, which were previously characterized in several studies, were all evaluated for VCG using an improved nit mutant assay. These isolates were also genotyped using 19 microsatellites developed from partial genome sequence of S. homoeocarpa. Additionally, partial sequences of mitochondrial genes cytochrome oxidase II and mitochondrial small subunit (mtSSU) rRNA, and the atp6-rns intergenic spacer, were generated for isolates from each nit mutant VCG to determine if mitochondrial haplotypes differed among VCGs. Of the 22 isolates screened, 15 were amenable to the nit mutant VCG assay and were grouped into six VCGs. The 19 microsatellites gave 57 alleles for this set. Unweighted pair group methods with arithmetic mean (UPGMA) tree of binary microsatellite data were used to produce a dendrogram of the isolate genotypes based on microsatellite alleles, which showed high genetic similarity of nit mutant VCGs. Analysis of molecular variance of microsatellite data demonstrates that the current nit mutant VCGs explain the microsatellite genotypic variation among isolates better than the previous nit mutant VCGs or the conventionally determined VCGs. Mitochondrial sequences were identical among all isolates, suggesting that this marker type may not be informative for US populations of S. homoeocarpa.

• Journal of Plant Biotechnology
• /
• v.43 no.4
• /
• pp.457-465
• /
• 2016

Microsatellites are one of the most suitable markers for identification of variety, as they have the capability to discriminate between narrow genetic variations. The polymorphism level between 120 microsatellite primer pairs and 148 soybean varieties was investigated through the fluorescence based automatic detection system. A set of 16 primer pairs showed highly reproducible polymorphism in these varieties. A total of 204 alleles were detected using the 16 microsatellite markers. The number of alleles per locus ranged from 6 to 28, with an average of 12.75 alleles per locus. The average polymorphism information content (PIC) was 0.86, ranging from 0.75 to 0.95. The unweighted pair group method using the arithmetic averages (UPGMA) cluster analysis for 148 varieties were divided into five distinctive groups, reflecting the varietal types and pedigree information. All the varieties were perfectly discriminated by marker genotypes. These markers may be useful to complement a morphological assessment of candidate varieties in the DUS (distinctness, uniformity and stability) test, intervening of seed disputes relating to variety authentication, and testing of genetic purity in soybean varieties.

• Journal of Korean Society for Atmospheric Environment
• /
• v.18 no.2
• /
• pp.113-126
• /
• 2002

This study was carried out to evaluate the temporal (daily, weekly, and seasonal) variations of volatile organic compounds (VOCs) concentrations at a road-side site in a heavy-traffic central area of Metropolitan Taegu. Ambient air sampling was undertaken continuously for 14 consecutive days in each of four seasons from the spring of 1999 to the winter of 2000. The VOC samples were collected using adsorbent tubes, and were determined by thermal desorption coupled with GC/MS analysis. A total of 10 aromatic VOCs of environmental concern were determined, including benzene, toluene, ethylbenzene, m＋p-xylenes, styrene, o-xylene, 1,3,5-trimethylbenzene, 1,2,4-trimethylbenzene, and naphthalene. Among 10 target VOCs, the most abundant compounds appeared to be toluene (1.5 ∼ 102 ppb) and xylenes (0.1 ∼ 114 ppb), while benzene levels were in the range of 0.3 ∼6 ppb. It was found that the general trends of VOC levels were significantly dependent on traffic conditions at the sampling site since VOC concentrations were at their maximum during rush hours (AM 7∼9 and PM 7 ∼9). However, some VOCs such as toluene, xylenes, and ethylbenzene were likely to be affected by a number of unknown sources other than vehicle exhaust, being attributed to the use of paints, and/or the evaporation of solvents used nearby the sampling site. In some instances, extremely high concentrations were found for these compounds, which can not be explained solely by the impact of vehicle exhaust. The results of this study may be useful for estimating the relative importance of different emission sources in large urban areas. Finally, it was suggested that the median value might be more desirable than the arithmetic mean as a representative value for the VOC data group, since the cumulative probability distribution (n=658) does not follow the normal distribution pattern.

• Journal of Environmental Health Sciences
• /
• v.33 no.5
• /
• pp.386-391
• /
• 2007

Mercury contamination and its health effects have become major concern of environmental health study in Korea. Mercury exposure of some group were investigated to get the accurate data for policy making and study. About 2,000 children at 26 elementary schools participated in this survey to evaluate the exposure levels and to investigate main exposure source of mercury. Analysis of mercury levels in the whole blood and urine samples were conducted and questionnaire survey was done about the factors influencing exposures simultaneously. Mercury exposure levels of domestic children were N.D. to 17.26 ppb in blood, 0.17 to $21.67{\mu}g/g$-creatinine in urine. The mean(arithmetic) levels are 2.42 ppb in blood and $2.53{\mu}g/g$-creatinine in urine. Both of them were below the recommendation levels of US EPA and German CHBM I $5.8{\mu}g/l$ and $5{\mu}g/l$ in blood, $5{\mu}g/g$-creatinine of German CHBM I in urine. But 1%, 0.51% of levels in blood exceed the level of CHBM I and US EPA, 8%, 0.85% of children were over the level of CHBM I and CHBM II in urine. Multi-valuable regression analysis showed that the existence of road near the residence in addition to the preference for fish have significance with blood mercury exposure level of domestic children. The existence of factory near the house and the experience of dental amalgam treatment had statistical relations with urine mercury level.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.14 no.8
• /
• pp.3295-3311
• /
• 2020

With the wide application of hyperspectral images, it becomes more and more important to compress hyperspectral images. Conventional recursive least squares (CRLS) algorithm has great potentiality in lossless compression for hyperspectral images. The prediction accuracy of CRLS is closely related to the correlations between the reference bands and the current band, and the similarity between pixels in prediction context. According to this characteristic, we present an improved CRLS with adaptive band selection and adaptive predictor selection (CRLS-ABS-APS). Firstly, a spectral vector correlation coefficient-based k-means clustering algorithm is employed to generate clustering map. Afterwards, an adaptive band selection strategy based on inter-spectral correlation coefficient is adopted to select the reference bands for each band. Then, an adaptive predictor selection strategy based on clustering map is adopted to select the optimal CRLS predictor for each pixel. In addition, a double snake scan mode is used to further improve the similarity of prediction context, and a recursive average estimation method is used to accelerate the local average calculation. Finally, the prediction residuals are entropy encoded by arithmetic encoder. Experiments on the Airborne Visible Infrared Imaging Spectrometer (AVIRIS) 2006 data set show that the CRLS-ABS-APS achieves average bit rates of 3.28 bpp, 5.55 bpp and 2.39 bpp on the three subsets, respectively. The results indicate that the CRLS-ABS-APS effectively improves the compression effect with lower computation complexity, and outperforms to the current state-of-the-art methods.

• Horticultural Science & Technology
• /
• v.35 no.2
• /
• pp.220-231
• /
• 2017

Grafting using a pumpkin (Cucurbita sp.) rootstock is an effective way to improve cucumber (Cucumis sativus) resistance to a combination of chilling and salinity stresses. We evaluated the tolerance of 15 pumpkin cultivars to chilling, salinity, and combined stresses at the germination and seedling stages. Selected plant characteristics, including germination rate, germination potential, germination index, plant height, stem thickness, fresh weight, and dry weight, were analyzed. We used the unweighted pair group method with arithmetic mean for cluster analyses to determine the stress tolerance levels of the pumpkin cultivars. The 15 cultivars were divided into three clusters: tolerant, moderately tolerant, and susceptible to stress treatments. The stress tolerances of all cultivars were variable in the germination and seedling stages, and most cultivars were not tolerant to individual treatments of chilling or salinity stresses at both stages. These results suggest that identifying suitable cultivars for use as rootstock during cucumber grafting should involve the evaluation of stress tolerance during different growth stages. Additionally, cultivars tolerant to chilling stress may not be tolerant to salinity stress; therefore, the choice of pumpkin rootstock should depend on where the grafted plant will be grown. Cultivars tolerant to a combination of chilling and salinity stresses may be useful as rootstock for cucumber grafting. Our findings may serve as reference material for choosing appropriate pumpkin rootstocks for cucumber grafting.

• Proceedings of the Korea Contents Association Conference
• /
• 2005.05a
• /
• pp.107-111
• /
• 2005

As Internet grows rapidly and next electronic commerce applications increase, the security is getting more important. Information security to provide secure and reliable information transfer is based on cryptography technique. The proposed ISEED(Improved SEED) algorithm based on block cryptography algorithm which belongs to secret-key algorithm. In terms of efficiency, the round key generation algorithm has been proposed to reduces the time required in encryption and decryption. The algorithm has been implemented as follow. 128-bit key is divided into two 64-bit group to rotate each of them 8-bit on the left side and right side, and then basic arithmetic operation and G function have been applied to 4-word outputs. In the process of converting encryption key which is required in decryption and encryption of key generation algorithm into sub key type, the conversion algorithm is analyzed. As a result, the time consumed to encryption and decryption is reduced by minimizing the number of plain text required differential analysis.

• Animal cells and systems
• /
• v.13 no.4
• /
• pp.419-427
• /
• 2009

The Minke whale, Balaenoptera acutorostrata, is the smallest baleen whale in the suborder Mysticeti. Because this species inhabits coastal areas, it became a main target species of coastal small-type whaling in the North Atlantic and the Northwest Pacific Oceans, and the species' population size dramatically decreased because of over-exploitation. As a result, the International Whaling Commission declared a global moratorium on whaling and launched the development of a management procedure for protecting the whales. Morphological studies, whaling history analysis, and genetic studies conducted mainly by Japanese scientists showed the existence of one unique "E" stock that inhabits the waters around the Korean peninsula and mixes with the "O" stock in the southern part of the Sea of Okhotsk. We used the mitochondrial DNA control region polymorphism of 348 Minke whales bycaught or stranded in Korean waters from 30 October 1998 to 25 June 2005 to assess the whale population structure by year. The frequency of the 10 major haplotypes from the 40 identified haplotypes was not significantly different among groups, suggesting that a subpopulation was not present. A comparison of the genetic distances calculated with Tamura-Nei's method showed that the distances between groups were lower than those within groups, which suggests that there was no genetic difference in the Minke whale populations. The Fst comparison between groups and the phylogenetic tree constructed using the unweighted pair group method with arithmetic mean (UPGMA) and Neighbor Joining (NJ) method also detected no obvious sub-stock structure.

• Korean Journal of Environment and Ecology
• /
• v.19 no.1
• /
• pp.46-54
• /
• 2005

The change of fish community in the Wonju-stream was investigated from May to November, 2004. During the period,24 species belonging to 6 families were collected. There were 10 Korean endemic species$(41.7\%)$, including Pseudopungtungia tenuicorpa, Coreoleuciscus spiendidus, Squalidus gracitis majimae, Squalidus japonicus coreanus, Microphysogobio yaluensis, Microphysogobio longidorsalis, Iksookimia koreensis, Koreocobitis rotundicaudata, Liobagus andersoni and Odontobutis interrupts. The dominant species was Zacco Platypus$(54.7\%)$, and the subdominant species was Rhynchocypris oxycephalus$(16.7\%)$. Also, Carassius auratus$(5.4\%)$, I. koreensis$(3.4\%)$, Orthrias toni$(3.3\%)$, and Pungtungia herzi$(3.0\%)$ appeared. According to the fish species compositions, the fish community was divided into 2 groups by an unweighted pair group method using arithmetic averages(UPGMA). The comparison of the fish community showed that benthic fish species were decreased, while, the number of water-column species, resistant 1,o substrate changes and water pollution were increased.