• Restorative Dentistry and Endodontics
• /
• v.17 no.1
• /
• pp.126-133
• /
• 1992

Tooth colored resin restorative materials are widely used in anterior teeth restorations. The color instability of resin was the main cause of failure in resin restorations. The purpose of this study was to investigate color stability and microhardness of serval visible light curing resins. Colorimetric measurements(Tokyo Denshoku Co., Japan) and microhardness tests(Matusuzawa, MXT 70, Japan) were made on six composite resins before and after controlled immersion treatments. The six composite resins were BIS - FILM(BISCO, USA), Durafill(Kulzer, Germany), Helioprogess(VIVADENT, Germany), Palfique(TOKUYAMA SODA, Japan), Silux(3M, USA), Photoclearfil(KURARAY, Japen). Six light curing resins showed significant color change after 2 weeks. Palfique exhibited the hightest $dE^*$ values and Helio progress presented the lowest $dE^*$ values. Photoclearfil showed the highest microhardness value. Durafill and Helio progress showed lower microhardness values. Microhardness values were decreased after 8 weeks in Bisfil, Palfique light, and Photoclearfil.

• Toxicological Research
• /
• v.25 no.1
• /
• pp.47-50
• /
• 2009

To investigate the mutation inducibility of surfactin C, we performed the chromosome aberration assay with Chinese hamster lung cells in vitro. The colorimetric MTT screening assay was carried out to determine the cytotoxicity index ($IC_{50}$) of surfactin C. The $IC_{50}$ value was $125{\mu}g/ml$. For the chromosome aberration test of surfactin C, the maximum concentration was employed as $125{\mu}g/ml$, followed by 62.5 and $31.25{\mu}g/ml$ for the lower concentrations, with or without metabolic activation (S9). Cyclophosphamide and mitomycin C were used as positive controls in the presence and absence of S9 metabolic activation, respectively. These results showed that surfactin C was not capable of inducing chromosome aberration, as measured by the chromosome aberration test using Chinese hamster lung cell line. There is no evidence for surfactin C to have a genotoxic potential.

• Korean journal of food and cookery science
• /
• v.19 no.5
• /
• pp.659-666
• /
• 2003

The purpose of this study was to standardize the various methods and recipes of Hwajeun (glutinous rice pancake with flower) that appeare in the literature. For this purpose, the effects on sensory and physical characteristics of Hwajeun in various kinds of dipping syrups (S1 : honey, S2 : rice syrup, S3 : com syrup, S4 : sugar syrup and S5 : sugar) during storage for 24hrs were investigated. This experiment consisted of the measurement of water content, color difference meter, texture analyser and sensory evaluation for acceptance (color, flavor, moistness, softness, chewiness, adhesiveness, sweetness and overall acceptability). The moisture contents decreased with increasing storage time, indicating that S1 had a significantly (p<0.01) high value until 12hrs. The colorimetric values of lightness (L), redness (a) and yellowness (b) decreased and the total color difference values ($\Delta$E) increased with increasing storage time. In the two bite compression test, the hardness of S1 and S3 showed significantly (p<0.0001) lower values than other samples. As a result of the sensory evaluation for Hwajeun prepared with various kinds of dipping syrup, S1 and S3 were most preferred in color, flavor, moistness, chewiness, adhesiveness, sweetness and overall acceptability of sensory evaluation.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.6 no.1
• /
• pp.77-87
• /
• 1996

In order to compare the difference of the measurement of delta aminolevulinic acid(${\delta}$-ALA) in urine between HPLC method(HALA) and colorimetric method(CALA), and also to provide useful information for the new diagnostic criteria of ${\delta}$-ALA in urine in lead poisoning, if at all possible in the future, authors studied 234 male lead workers who were selected from 7 storage battery factories, 3 secondary smelting industries, and 2 litharge making industries. Study subjects were selected on the basis of blood Zinc protoporphyrin(ZPP) level from low to high concentration to cover wide range of lead exposure. Study variables for this study were ${\delta}$-ALA measured by two different methods, blood lead(PbB), and blood ZPP. The results were as follows: 1. There was very high correlation between ${\delta}$-ALA measured by two method(r = 0.989 : HALA = -0.8194 + 0.8110 ${\times}$ CALA), but the value of CALA was measured about 2mg/L greater than HALA. 2. While the correlations of ${\delta}$-ALA by two method with blood lead and blood ZPP were 0.46 and 0.37 respectively, they were increased to 0.63 and 0.57 if ${\delta}$-ALA values were log-transformed. 3. Simple linear regression of ${\delta}$-ALA measured by two method on ZPP were as follows: CALA = 2.0421 + 0.0341 ${\times}$ ZPP ($R^2=0.1385$ p = 0.0001) HALA = 0.8006 + 0.0280 ${\times}$ ZPP ($R^2=0.1389$ p = 0.0001) 4. Simple linear regression of ${\delta}$-ALA measured by two method on PbB were as follows: CALA = - 0.4134 + 0.1545 ${\times}$ PbB ($R^2=0.2085$ p = 0.0001) HALA = -1.2893 + 0.1287 PbB ($R^2=0.2154$ p = 0.0001), 5. Simple linear regression of log-transformed ${\delta}$-ALA by two method on ZPP and PbB were as follows: logHALA = 0.3078 + 0.0060 ZPP ($R^2=0.3329$ p = 0.0001) logCALA = 1.0189 + 0.0044 ZPP ($R^2=0.3290$ p = 0.0001) logHALA = -0.0221 + 0.0246 PbB ($R^2=0.4046$ p = 0.0001) logCALA = 0.7662 + 0.0184 PbB ($R^2=0.4108$ p = 0.0001) 6. The cumulative percent of colorimetric method to detect lead workers whose value of PbS and ZPP were over screening level such as $40{\mu}/dl$ and $100{\mu}/dl$ respectively was higher than HPLC method if cut-off level of ${\delta}$-ALA for screening of lead poisoning was 5 mg/L. But if cut-off level of ${\delta}$-ALA measured by HPLC was reduced to 3 mg/L which is compatible to 5 mg/L of ${\delta}$-ALA measured by colorimetric method, there were good agreement between two methods and showed dose-response relationship with other lead exposure indices such as PbB and ZPP.

• Korean journal of food and cookery science
• /
• v.26 no.2
• /
• pp.111-120
• /
• 2010

The aim of this research was to develop a practical use of the citron (Citrus junos Sieb.) leaf, which is a by-product of the citron cultivation, by introducing it into the Jeolpyun, one of the most popular rice cakes in Korea. To achieve the goals of this research, the citron leaf Jeolpyun (CLJ) was first precipitated. The sensory properties and physical examination of products containing 0 (control), 1.0, 1.5, 2.0, and 2.5% of the dried citron leaf powders were then assessed by employing sensory evaluations and instrumental measurements for texture and color. A total of one-hundred and fifty women panelists in age categories of 20s, 30s, 40s, and over 50 were randomly selected from residents in the Seoul area. In general, the highest sensory evaluation scores were obtained for CJLs containing 2% of the citron leaf powders by all panel groups although there was some variation. As levels of the citron leaf powder in the CLJ increased, the texture parameters such as hardness, cohesiveness, and gumminess of the CLJ as measured by the Texture Analyzer significantly increased while adhesiveness decreased and springiness remained constant. Accordingly, the optimal amount of citron leaf powder was determined to be 2% or less for CLJ in order to maintain the original texture of the Jeolpyun. As the levels of the citron leaf powder increased in the CLJ, the Hunter colorimetric L-and a-value significantly decreased while the b-value significantly increased. In other words, the CLJs became darker, as well as deeper in green and yellow tones as the levels of the citron leaf powder increased. The above results indicate that the citron leaf could be successfully used for preparation of Jeolpyun at a concentration around 2%(w/w) based on the consumer preference test and instrument analysis of the products. This research is expected to contribute to the industrial use of citron leaf powder in Jeolpyun and other food products.

• Korean Journal of Medicinal Crop Science
• /
• v.7 no.1
• /
• pp.37-44
• /
• 1999

This study was conducted to screen antitumoral activity by in vitro bioassay method using 60 Korean medicinal and food plants extracted by 80% EtOH. Antitumor activity test was applied by the PKC(protein kinase C) and antibleb formation, PLC (Phospholipase C), and colorimetric tetrazolium assay (MTT assay) methods. Chenopodjum album and black Glycine max showed high antitumoral activity by 73.5% and 81.0%, respectively, against PKC by bleb-forming assay and PKC enzyme assay on human chronic leukemia K562 cell. Black Glycine max also showed 91.2% antitumoral activity in the PLC method and the lowest $IC_{50}$ $value(4.7{\mu}g/ml)$ by MTT method against P-338 cell line. In the effect of the concentration treatment on antitumoral test, the more concentration indicated the more activity value.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.44 no.2 s.314
• /
• pp.46-54
• /
• 2007

In current printer industry, four or more colorants are added for color gamut extension because the gamut of printer is smaller than other devices. However, these additional colorants make a redundancy problem that several combinations of colorants reproduced same color stimulus in colorimetric inverse characterization process. Thus, we propose a method of colorimetric inverse characterization using color correlation between colorant's amount. First, for analyzing the combination of colorants which represent the same color stimulus, we estimate the color stimulus for all combination of colorants by Cellular Yule-Nielsen Spectral Neugebauer printer model. The combination of colorants which has higher color correlation factor comparing combinations of colorant around itself in color space is selected. It can reduced the color difference from the tetrahedral interpolation process which is estimation of the output value(colorants combination) for arbitrary input(color stimulus). The selected combinations of colorants and their color stimulus are stored to the lookup table. In experiment, the CMYKGO printer was used. As a result, the dark region of color gamut was extended and the color tone was more naturally represented.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.42 no.4 s.304
• /
• pp.49-59
• /
• 2005

This paper proposed a six-color separation using additional colorants and quantitative granularity metric to reduce color difference and graininess. In the conventional method, light magenta and light cyan are used in the bright region instead of magenta and cyan. However, the hue value of liBht magenta and light cyan is different from the one of magenta and cyan in CIELAB space, so that this makes the colorimetric reproduction more or less inaccurate. To improve this inaccuracy, the proposed method uses yellow and light magenta colorants as the additional colorants. In the bright region, magenta is replaced with light magenta and yellow, while cyan is replaced with light cyan and light magenta. This selection reduces hue difference because it creates the color of similar hue to magenta and cyan. In addition, smooth image can be simultaneously obtained by the less dot visibility of additional colorants. In the middle region, magenta is replaced with light magenta and magenta, while cyan is replaced with light cyan and cyan. The use of two colorants having a different concentration makes the dot Pattern coarse. To reflect this Phenomenon, quantitative granularity metric is used. In the dark region, only magenta and cyan colorant is used as usual. Through experiments, it is shown that the proposed method improves both colorimetric and smooth tone reproductions.

• Korean Journal of Plant Resources
• /
• v.23 no.2
• /
• pp.145-150
• /
• 2010

To examine the antioxidative effect and melanogenesis of Nelumbo nucifera stamen (NNS) extract on hydrogen peroxide $H_2O_2$ induced cytotoxicity in cultured human skin melanoma cells (SK-MEL-3), cell adhesion activity (CAA), tyrosinase inhibitory activity and total amount of melanin synthesis were measured by colorimetric assay. In this study, $H_2O_2$ significantly decreased CAA, and $CAA_{50}$ value of $H_2O_2$ was determined at 30 uM. In the antioxidative effect, NNS extract increased cell adhesion activity which was decreased by $H_2O_2$ induced cytotoxicity, and also, tyrosinase activity and total amount of melanin were decreased by NNS extract. These results suggested that $H_2O_2$ was highly toxic on cultured human skin melanoma cells and NNS extract showed the antioxidative and inhibitory effect of melanogenesis by the increased CAA, and the decresed tyrosinase activity and total amount of melanin synthesis.

• Food Science and Preservation
• /
• v.24 no.5
• /
• pp.585-592
• /
• 2017

The purpose of this study was to prepare blueberry syrup (cheung) using fructooligosaccharide instead of the traditionally used sucrose. The sugar content, pH, and colorimetric values were measured to evaluate the quality of the prepared syrup, and the antioxidant activity and phenolic compound content were determined to assess the physiological activity of the syrup. The $L^{\ast}$ value (lightness), pH, and color were high in syrups containing a high proportion of fructooligosaccharide. The $a^{\ast}$ value (redness) was high in syrups subjected to heat treatment, and the $b^{\ast}$ value (yellowness) tended to be the opposite of the $L^{\ast}$ value. Moreover, syrups containing heat-treated fructooligosaccharide showed higher polyphenol, flavonoid, and anthocyanin contents than the unheated syrups did. The antioxidant activity of the blueberry cheung depended on the content of phenolic compounds. The highest value was obtained in the cheung prepared using a heat-treated 1:1 mixture of blended raw blueberry and fructooligosaccharide (S2). These findings suggest that our familiarity with the taste of the sweetener used influences our taste preference. It is therefore necessary to study other newly developed sweeteners apart from fructooligosaccharide to find a suitable alternative to sucrose.