• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.2
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• pp.188-194
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• 2000

Thermochromic liquid crystal reflect a unique color at even temperature. Therefore, they have been successfully applied to non-intrusive heat transfer research. Hue capturing method is widely used in the quantitative measurement from the TLC image. However it is affected by several measurement conditions. The distances of camera and light source have little influence on the color, but the value of hue is seriously affected by the measurement angle. In this study, the hue capturing method is improved by considering the effect of measurement angle. This improved calibration method can diminish the misreading of temperature caused by curvature of test surface.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.727-733
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• 2011

A new Korean standard for the determination of Cr(VI) in soils has been officially published as ES 07408.1 in 2009. This analytical method is based on the hot alkaline digestion and colorimetric detection prescribed by U.S. EPA method 3060A and 7196A. The hot alkaline digestion accomplished using 0.28 M $Na_2CO_3$ and 0.5 M NaOH solution (pH 13.4) at $90{\sim}95^{\circ}C$ determines total Cr(VI) in soils extracting all forms of Cr(VI), including water-soluble, adsorbed, precipitated, and mineral-bound chromates. This aggressive alkaline digestion, however, proved to be problematic for certain soils which contain large amounts of soluble humic substances or active manganese oxides. Cr(III) could be oxidized to Cr(VI) by manganese oxides during the strong alkaline extraction, resulting in overestimation (positive error) of Cr(VI). In contrast, Cr(VI) reduction by dissolved humic matter or Fe(II) could occur during the neutralization and acidic colorimetric detection procedure, resulting in underestimation (negative error) of Cr(VI). Futhermore, dissolved humic matter hampered the colorimetric detection of Cr(VI) using UV/Vis spectrophotometer due to the strong coloration of the filtrate, resulting in overestimation (positive error) of Cr(VI). Without understanding the mechanisms of Cr(VI) and Cr(III) transformation during the analysis it could be difficult to operate the experiment in laboratory and to evaluate the Cr(VI) results. For this reason, in this paper we described the theoretical principles and limitations of Cr(VI) analysis and provided useful guidelines for laboratory work and Cr(VI) data analysis.

• Archives of Pharmacal Research
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• v.14 no.3
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• pp.207-216
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• 1991

Pseudixus japonicus agglutinin (PJA) was isolated. And its characteristics were compared with those of concanavalin A (Con A). PJA is a glycopritein composed of 49.3% carbohydrate and 50.7% protein which had relatively high percentages of glutamic acid, aspartic acid and phenylalanine residues. The hemagglutinating activity of PJA was approximately one-eighth of that of Con A when tested with mouse crythrocytes. PJA failed to simulate the proliferation or transformation of human and mouse lymphocytes in contratst to Con A. PJA and Con A showed cytotoxicities against SNU-1 (human stomach cancer cells), SNU-CI (human colon cancer cells) and mouse Sarcoma 180 cells when tested by 3-(4, 5-dimethyl thiazol-2-yl)2. 5-diphenyl tetrazolium bromide (MIT) colorimetric assay. The antitumor activity of the lectin in vivo was also tested in Sarcoma 180 bearing mice. There was no significant difference in prologation of lifc span of the mice after the treatment with PJA and Con A for 10 consecutive days.