• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.11
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• pp.1610-1616
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• 2016

This study aimed to establish an optimal extraction process and high performance liquid chromatography-ultraviolet (HPLC-UV) analytical method for determination of 3,5-dicaffeoylquinic acid (3,5-DCQA) as a part of materials standardization for the development of a xanthine oxidase inhibitor as a health functional food. The quantitative determination method of 3,5-DCQA as a marker compound was optimized by HPLC analysis using a Luna RP-18 column, and the correlation coefficient for the calibration curve showed good linearity of more than 0.9999 using a gradient eluent of water (1% acetic acid) and methanol as the mobile phase at a flow rate of 1.0 mL/min and a detection wavelength of 320 nm. The HPLC-UV method was applied successfully to quantification of the marker compound (3,5-DCQA) in Aster glehni extracts after validation of the method with linearity, accuracy, and precision. Ethanolic extracts of A. glehni (AGEs) were evaluated by reflux extraction at 70 and $80^{\circ}C$ with 30, 50, 70, and 80% ethanol for 3, 4, 5, and 6 h, respectively. Among AGEs, 70% AGE at $70^{\circ}C$ showed the highest content of 3,5-DCQA of $52.59{\pm}3.45mg/100g$ A. glehni. Furthermore, AGEs were analyzed for their inhibitory activities on uric acid production by the xanthine/xanthine oxidase system. The 70% AGE at $70^{\circ}C$ showed the most potent inhibitory activity with $IC_{50}$ values of $77.01{\pm}3.13{\sim}89.96{\pm}3.08{\mu}g/mL$. The results suggest that standardization of 3,5-DCQA in AGEs using HPLC-UV analysis would be an acceptable method for the development of health functional foods.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.4
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• pp.298-303
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• 1981

A study was conducted to find out the varietal difference in some important agronomic characters in response to different seeding time in barely from 1975 to 1976 at Chikugo Agric. Expt. Station in Japan. Thirteen varieties which are diverse in growth period were used. Nine seeding time were tried. Seedling emergence, primary tillering, and formation of flower primodia were delayed in proportion to the seeding time. And also heading and maturing time showed the same tendency. This tendency appeared more conspicuous in the late maturing varieties. Therefore, days to heading and maturing duration were inversely shortened by the delay of seeding time and by earliness of variety. Number of spikes as well as culm length and spike length was reduced in the late seeding. Grain yield was reduced in all varieties by late seeding, easpecially with late maturing varieties. In this test, widely adaptable variety to late seeding time was not found, but earliness and high tillering in growth habit appeared more favorable to yield increase.

• Journal of Dairy Science and Biotechnology
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• v.14 no.2
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• pp.157-164
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• 1996

This study aimed increase the quality during ripening of Cheddar cheese made with proteinase-negative mutant of Streptococcus lactis KCTC 1913 selected by curing. The degradation of protein during cheese ripening were investigated by electrophoresis and chromatography. The results were summarized as follow ; 1. The number of lactic acid bacteria decreased with the ripening stage, and that of the control cheese decreased faster than that of the cheese made with mutant. 2. Polyacrylamide gel electrophoretic analysis of cheese caseins revealed no difference between the cheese made with mutant and the control cheese, but differences along with the ripening stage were evident. 3. On Sephadex G-25 column chromatography, the extracts of bitter components from the green cheese and 3 month ripended cheese were fractionated into 3 fractions. With the progress of ripening, bitter peptides were degraded to rather small peptides or free amino acids. 4. Sensory evaluation of the 3 month ripended Cheddar cheese found no significant differences in color but the cheese made with mutant evidenced higher palatability in flavor and better texture than the control cheese. 5. The yields of the cheddar cheese made with mutant was 0.14% higher than that of the control cheese.

• Korean Journal of Environmental Agriculture
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• v.30 no.3
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• pp.288-294
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• 2011

BACKGROUND: Methylmercury is analyzed by HPLC-ICP/MS because of the simplicity for sample preparation and interference. However, most of the pre-treatment methods for methylmercury need a further pH adjustment of the extracted solution and removal of organic matter for HPLC. The purpose of this study was to establish a rapid and accurate analytical method for determination of methylmercury in fish by using HPLC-ICP/MS. METHOD AND RESULTS: We conducted an experiment for pre-treatment and instrument conditions and analytical method verification. Pre-treatment condition was established with aqueous 1% L-cysteine HCl and heated at $60^{\circ}C$ in microwave for 20 min. Methylmercury in $50{\mu}L$ of filtered extract was separated by a C18 column and aqueous 0.1% L-cysteine HCl + 0.1% L-cysteine mobile phase at $25^{\circ}C$. The presence of cysteine in mobile phase and sample solution was essential to eliminate adsorption, peak tailing and memory effect problems. Correlation coefficient($r^2$) for the linearity was 0.9998. The limits of detection and quantitation for this method were 0.15 and $0.45{\mu}g/kg$ respectively. CONCLUSION: Result for analytical method verification, accuracy and repeatability of the analytes were in good agreement with the certified reference materials values of methylmercury at a 95% confidence level. The advantage of the established method is that the extracted solution can be directly injected into the HPLC column without additional processes and the memory effect of mercury in the ICP-MS can be eliminated.

• Analytical Science and Technology
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• v.25 no.2
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• pp.121-126
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• 2012

It is essential to evaluate the quality of Hanji record paper without damaging the record paper by previous destructive methods. The samples were Hanji record paper produced in the 1900s. Near-infrared (NIR) spectrometer was used as a non destructive method for evaluating the quality of record papers. Fourier transform (FT) spectrometer was used with 12,500 to 4,000 $cm^{-1}$ wavenumber range for quantitative analysis and it has high accuracy and good signal-to-noise ratio. The acidity and moisture content of Hanji record paper were measured by integrating sphere as diffuse reflectance type. The acidity (pH) of chemical factors as a quality evaluated factor of Hanji was correlated to NIR spectrum. The NIR spectrum was pretreated to obtain the coefficients of optimum correlation. Multiplicative scatter correction (MSC) and First derivative of Savitzky-Golay were used as pretreated methods. The coefficients of optimum correlation were calculated by PLSR (partial least square regression). The correlation coefficients ($R^2$) of acidity had 0.92 on NIR spectra without pretreatment. Also the standard error of prediction (SEP) of pH was 0.24. And then the NIR spectra with pretreatment would have better correlation coefficient ($R^2$ = 0.98) and 0.19 as SEP on pH. For moisture contents, the linearity correlation without pretreatment was higher than the case with pretreatment (MSC, $1^{st}$ derivative). As the best result, the $R^2$ was 0.99 and SEP was 0.45. This indicates that it is highly proper to evaluate the quality of Hanji record papers speedily with integrated sphere and FT NIR analyzer as a non-destructive method.

• The Korean Journal of Pesticide Science
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• v.19 no.1
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• pp.5-13
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• 2015

A chromatographic method for the determination of imazapyr, a non-selective herbicide, in agricultural commodities was developed to use safety control of pesticide residue on crops, and was fully validated as an official method for residue analysis. Agricultural commodities, mandarin (fruit), hulled rice (cereal grains), pepper (vegetables), potato (potatoes) and soybean (beans) were extracted with methanol and partitioned with dichloromethane to remove the interference obtained from sample extracts, adjusting pH to 2.5 by 4N hydrochloric acid. Finally, they were analyzed by high performance liquid chromatography coupled to UV detector (HPLC-UVD). The developed method had the linearity in the range of test concentrations with coefficients of determination ($r^2$) more than 0.99. Recovery studies were carried out at three concentration levels (LOQ, 10LOQ, and 50LOQ) performing five replicates at each level. Recoveries were ranged between 72.1 to 108.0%, with relative standard deviations less than 10%. A consistent recovery was determined according to the CODEX guidelines (CAC/GL40, 2003). Finally, LC/MS with selected ion monitoring was also applied to confirm the suspected residues of imazapyr in agricultural samples. This developed method for determination of imazapyr residues in agricultural commodities. can be used as an official method.

• Journal of Intelligence and Information Systems
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• v.21 no.3
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• pp.19-36
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• 2015

Social media is an emerging issue in content services and in current business environment. YouTube is the most representative social media service in the world. YouTube is different from other conventional content services in its open user participation and contents creation methods. To promote a content in YouTube, it is important to understand the diffusion phenomena of contents and the network structural characteristics. Most previous studies analyzed impact factors of contents diffusion from the view point of general behavioral factors. Currently some researchers use network structure factors. However, these two approaches have been used separately. However this study tries to analyze the general impact factors on the view count and content based network structures all together. In addition, when building a content based network, this study forms the network structure by analyzing user comments on 22,370 contents of YouTube not based on the individual user based network. From this study, we re-proved statistically the causal relations between view count and not only general factors but also network factors. Moreover by analyzing this integrated research model, we found that these factors affect the view count of YouTube according to the following order; Uploader Followers, Video Age, Betweenness Centrality, Comments, Closeness Centrality, Clustering Coefficient and Rating. However Degree Centrality and Eigenvector Centrality affect the view count negatively. From this research some strategic points for the utilizing of contents diffusion are as followings. First, it is needed to manage general factors such as the number of uploader followers or subscribers, the video age, the number of comments, average rating points, and etc. The impact of average rating points is not so much important as we thought before. However, it is needed to increase the number of uploader followers strategically and sustain the contents in the service as long as possible. Second, we need to pay attention to the impacts of betweenness centrality and closeness centrality among other network factors. Users seems to search the related subject or similar contents after watching a content. It is needed to shorten the distance between other popular contents in the service. Namely, this study showed that it is beneficial for increasing view counts by decreasing the number of search attempts and increasing similarity with many other contents. This is consistent with the result of the clustering coefficient impact analysis. Third, it is important to notice the negative impact of degree centrality and eigenvector centrality on the view count. If the number of connections with other contents is too much increased it means there are many similar contents and eventually it might distribute the view counts. Moreover, too high eigenvector centrality means that there are connections with popular contents around the content, and it might lose the view count because of the impact of the popular contents. It would be better to avoid connections with too powerful popular contents. From this study we analyzed the phenomenon and verified diffusion factors of Youtube contents by using an integrated model consisting of general factors and network structure factors. From the viewpoints of social contribution, this study might provide useful information to music or movie industry or other contents vendors for their effective contents services. This research provides basic schemes that can be applied strategically in online contents marketing. One of the limitations of this study is that this study formed a contents based network for the network structure analysis. It might be an indirect method to see the content network structure. We can use more various methods to establish direct content network. Further researches include more detailed researches like an analysis according to the types of contents or domains or characteristics of the contents or users, and etc.

• Journal of the Korean Institute of Landscape Architecture
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• v.44 no.4
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• pp.1-13
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• 2016

To detail a picture of the economic value of Miscanthus landscape conservation in terms of cultural services aspects of Ecosystem Services, Sunghaksan(Mt.), Hwawangsan(Mt.) and Jaeyaksan(Mt.), which are known for their Miscanthus colonies, were chosen as survey sites. After examining the willingness to pay for the value of Miscanthus landscape conservation by targeting of visitors each study area, the economic value of Miscanthus landscape conservation per capita aspects was evaluated using Contingent Valuation Methods(CVM) from the collected willingness to pay for economic value of Miscanthus scenery by site. After using the target Chi-square test to analyze the differences among each site, the correlation between specific variables was investigated. Willingness to pay for the Miscanthus landscape conservation was found to increase as the respondents' income became higher. The more environmental conservation efforts were being made in their daily life, the higher willingness to pay was for Miscanthus landscape conservation. Likewise in other studies, the higher the bid was, the less willingness to pay was. The per capita assessment of the Miscanthus landscape value of the logit models in the dual estimated using the factor extracted with each of the injected variable bounds was estimated for Seunghaksan (\38,277), Hwawangsan(\38,648), and Jaeyaksan(\48,891). The average of the three sites was estimated to be \38,679. Assessment of the economic value of these Miscanthus landscape sites saw high willingness to pay by visitors when compared to the current market price inflation, such as watching movies or amusement park admission, which could mean that visitors recognize the value of ecosystem services from nature in evaluating the Miscanthus landscape.

• Restorative Dentistry and Endodontics
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• v.18 no.1
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• pp.73-83
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• 1993

The purpose of this study was to evaluate the effect of various acid treatments on dentin bonding. Freshly extracted human teeth were uprightly embedded in self curing acrylic resin, and their occlusal surfaces were grinded to expose flat dentin surfaces. The specimens were divided into 4 groups. Specimens of one group were not treated so as to be a control and those of the other three groups were threated with 10% polyacrylic acid, 10% phosphoric acid, and 10-3 solution(10% citric acid/3% ferric chloride) respectively. Primer, bonding resin and composite resin were applied over the treated dentin surfaces sequentially. All specimens were stored in $37^{\circ}C$ distilled water for 24 hours, then the tensile bond strength was measured and the treated dentin surfaces and fracured dentin surfaces were examined under a scanning electron microscope. The results were as follows: Bond strengths of acid-treated groups were higher than those of the untreated group. In the acid-treated groups, bond strength was found to be the highest in the 10-3 solution group followed by the 10% phosphoric acid group and the 10% polyacrylic acid group(P<0.01). On SEM examination of dentin surfaces, the untreated dentin surface showed a remaining smear layer and closed dentinal tubules. Dentin surfaces treated with 10 % polyacrylic acid showed a clean dentin surface without the smear layer, but showed remaining smear plugs in dentinal tubules. A dentin surface treated with 10% phosphoric acid or 10-3 solution showed open dentinal tubules without the smear layer or smear plugs. On SEM observation of the fractured dentin-resin interface, the untreated group showed that failure occurred in the smear layer. The group treated with 10% polyacrylic acid showed no resin tag remained in the dentinal tubules, but resin tags in the dentinal tubules were observed in the group treated with the 10% phosphoric acid or the 10-3 solution. On the failure mode examination, the higher the bond strength of the group, the higher the frequency of cohesive failure. The coefficient between bond strength and cohesive failure rate was 0.71.

• Journal of Preventive Medicine and Public Health
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• v.16 no.1
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• pp.59-65
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• 1983

Screening data from preplacement and periodic examination in Gu Mi Industrial Estate from May, 1983 to June, 1983 provide an opportunity to evaluate the accuracy of self-reported height and weight. The data for men and women were analyzed separated for effects of age, marrital status, educational level, employment status, measured height, measured weight and relative weight (percent of ideal body weight). The mean percent discrepancy from self-reported and measured height was analysed by cross-tubulation, P. value for analysis of variance and multiple correlation analysis in men and women. It is clear from the data that self-reported height and weigt differ from the quantities in systemic ways. But the magnitude of misreporting is very small on average except for weight in women. Whereas height tend to be over-reported, weight is under-reported in women but over-reported in men. Weight was accuracte for age group 20-29 years in men and age group over 40 year in women and over-reporting of weight increased with age in men and under-reporting of weight decreased with age in women. Weight was accurate in 60-64kg group in men and under 50kg group in women and under-stating of weight increased with weight in men and women. Weight was the most accurate in 100-109 percent relative weight group in men and in 90-99 percent relative weight group in women and under-stating of weight increased with relative weight and over-stating decreased with relative weight and over-stating decreased with relative weight in men and women. Height was the most accurate for group of primary school and except group of primary school, accuracy of height increased with educational level in men and women. In height, the highest measured height groups (over than 175cm measured height in men and over than 165cm measured height in women) were the most accurate and of over-reporting of height decreased with measured height. Single variable regression analysis and ANOVAs showed age(P<0.003), measured weight(P<0.0001) relative weight(P<0.0001), educational level(P<0.0005) and employment status(P<0.0007) to be significantly related to ${\Delta}WT$ in women and measured height(P<0.0001), educational level(P<0.03) and marrital status (P<0.03) to be significantly related to ${\Delta}WT$ in men. The women were more sensitive about her body weight than height.