• Applied Chemistry for Engineering
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• v.34 no.2
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• pp.131-136
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• 2023

We developed a method to measure the concentration of highly concentrated colored samples using color coordinates. We present a color analysis to estimate the concentration of highly concentrated binary solutions with an empirical function and apply it to estimate the kinetics of a catalytic irreversible reaction of resazurin to resorufin. The developed method enabled one to measure the concentration of solutions whose range of concentrations is nonlinear and beyond the limit of UV-vis spectroscopic measurement directly without dilution.

• Journal of Biosystems Engineering
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• v.22 no.4
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• pp.479-486
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• 1997

식물 뿌리에 대한 지식은 식물-토양 사이의 관계 이해, 토양의 호율적 관리, 식물에 의한 영양분과 수분의 흡수 과정 이해, 그리고 토양 등급 지수를 만드는데 있어서 아주 중요하다 식물 뿌리에 관한 정보를 정량화하기 위하여는 뿌리를 흙으로부터 씻어내고 뿌리의 길이, 표면적, 중량과 같은 식물 뿌리의 특성을 측정하여야 한다 하지만 이렇게 뿌리를 씻어 낸 다음 뿌리의 특성을 측정하는 기존의 방법을 이용할 경우 막대한 시간과 노동력이 필요하여 뿌리에 관한 많은 양의 정보를 얻는데 큰 어려움이 있다. 이 연구에서는 식물 뿌리를 관측하는데 필요한 시간과 노동력을 줄일 수 있는 식물 뿌리 측정법을 세선 작업과 자외선 명암 증진법을 이용한 영상 정보 처리 장치를 바탕으로 하여 개발하였다. 개발된 화상 정보 처리 장치를 이용하여 옥수수 뿌리의 길이를 재었을 때 기존의 뿌리 길이 측정 방법보다 2.5 배 발리 측정할 수 있는 것으로 나타났다.

• Analytical Science and Technology
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• v.13 no.3
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• pp.304-308
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• 2000

The iodide was recovered from a simulated spent fuel to the sodium bisulfite aqueous solution. It was discussed that the trace iodide (below 1 ppm) was determined without the matrix effect of 0.1 M sodium bisulfite and 1 mM $HNO_3$ in aqueous solution by ion chromatography with UV detection. AS4A-SC (DIONEX) column and UV-absorption spectrophotometer were used. The UV-absorption spectra of sodium bisulfite, nitric acid and iodide were obtained, and then 230 nm was selected as an absorption wavelength for iodide determination. 0.1 M NaCl eluent was optimum condition. In this condition the calibration curve of iodide was obtained on the range of about 0-1,000 ppb. The linear coefficient was 0.99993 and the detection limit was 5 ppb. The relative standard deviation was 1.26%.

• Ocean and Polar Research
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• v.32 no.4
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• pp.397-409
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• 2010

Herein, we compared the production rate of UV-absorbing compounds (mycosporine-like amino acids) and carotenoids in two phytoplankton species--Phaeocystis pouchetii and Porosira glacialis--which are the dominant species in Polar Regions under artificial UV radiation conditions. P. pouchetii exposed to UVR and PAR evidenced reductions in the carbon fixation rate, and was not significantly influenced by differing light conditions. However, the concentrations of UV-absorbing compounds and photo-protective pigments of P. pouchetii were increased with increasing exposure time, but P. glacialis maintained constant levels during the UVR exposure experiment. The production rates of MAAs showed a reverse phase between the two phytoplankton species. The carbon fixation rate of P. pouchetii cells was inhibited by exposure to UV radiation, but the production rates of MAAs in P. pouchetii were increased under UV radiation exposure. The carbon fixation rate and production rate of MAAs in P. glacialis were simultaneously inhibited under UV radiation exposure conditions. These results provide us with new information regarding the processes involved in the production of UV-absorbing compounds and photoprotective pigments in two phytoplankton species.

• Polymer(Korea)
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• v.31 no.5
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• pp.393-398
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• 2007

We studied the mechanism of liquid crystal alignment on polyvinylfluorocinnamate (PVCN-F) films which were irradiated by UV using polarized fourier transform infrared (FT-IR) spectroscopy and ultraviolet/visible (UV/Vis) spectroscopy. UV irradiation of PVCN-F films caused decrease of vinylene -C=C- stretching peak area at $1638cm^{-1}$ and shift of conjugated C:0 stretching vibration at $1712cm^{-1}\;to\;1734cm^{-1}$ which is caused by nonconjugated C=O stretching nitration. To study the orientation direction of 5CB liquid crystal (LC) molecules in the liquid crystal cell with PUV irradiation, rubbing treatment or without any treatment on the PVCN-F alignment layer, we used polarized FT-IR dichroism technique. We successfully measured 5CB LC alignment directions, which are perpendicular to the irradiated PUV polarization direction and parallel to the rubbing direction in the liquid crystal cell without using dichroic dyes.

• Applied Biological Chemistry
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• v.26 no.1
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• pp.8-18
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• 1983

The effects of fat-solvents was investigated on the yield. brown color intensity, UV absorbance patterns, reducing and antioxidant activities, and variation of fatty acid composition of the extracts from white and red ginseng. The yield and intensity of brown color of extracts were generally greater as the polarity of the solvent used became stronger. The intensity of the brown color of extract of red ginseng was greater than that of white ginseng. The orders of reducing and antioxidant activities of extracts of red ginseng was similar that of white ginseng, resulting in decreasing order of: ethanol>methanol>ethyl acetate, acetone>ether>chloroform>benzene, hexane. The ethanol, methanol, and ethyl acetate extracts of red ginseng showed stronger UV absorption than the corresponding extracts of white ginseng. The former also possessed stronger reducing and antioxidant activities than the latter. The composition of the major unsaturated fatty acids (linoleic, linolenic, and nervonic acid) in the ethanol and ethyl acetate extracts from both white and red ginseng did not change appreciably for 60 days at $45^{\circ}C$. In case of the hexane extracts which had shown the weakest reducing and antioxidant activities among the extracts, linolenic acid disappeared almost under the same condition.

• Korean Chemical Engineering Research
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• v.47 no.5
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• pp.553-557
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• 2009

Root extracts of Angelica gigas Nakai were tested to see the possibility for functional cosmetic agents. From ethanol extraction method, 97% of decursin and decursinol angelate was obtained, and concentration ratio of decursin to decursinol angelate was about 3:2. To test possibility as a functional cosmetic agent, DPPH free radical scavenging assay, UVA/B absorption, tyrosinase inhibition assay, melanogenesis inhibition assay, elastase inhibition assay and MTT assay were done. Root extracts of Angelica gigas Nakai showed $45.2{\pm}3.9%$ tyrosinase inhibition of tyrosine, and $24.2{\pm}12.0%$ melanin inhibition at $15{\mu}g/ml$ extract concentration, so that it indicated good whitening effect. DPPH free radical scavenging activity was $40.9{\pm}9.1%$ at $240{\mu}g/ml$ concentration, which is relatively good. Anti-wrinkle effect was poor such that it was $12.7{\pm}6.8%$ at $100{\mu}g/ml$. UVA/B absorption was also negligible. From the research, root extracts of Angelica gigas Nakai showed good potential as a whitening agent.

• Journal of Bio-Environment Control
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• v.21 no.3
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• pp.180-185
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• 2012

The objective of this study was carried out to elucidate the effect of LEDs (light emitting diodes) irradiation in relation to early growth and inorganic elements in leaf lettuce (Lactuca sativa L. 'Rollo Rosa'). In morphological changes of leaves, shoot elongation and hypocotyl length showed poor growth in red light irradiation, while the red + blue light irradiation induced shorter plant height and much greater leaf numbers resulting in increased fresh weight. In change of the Hunter's color and SPAD values, lettuce seedlings grown under in red + blue and fluorescent light irradiation had a higher $a^*$ value, otherwise SPAD values were not changed in these light irradiations. Interestingly, relative chlorophyll contents showed 1.8 times increased redness in the treatment of red + blue light irradiation. Inorganic element (N, Ca, Mg, Mn, and Fe) and ascorbic acid contents were increased in lettuce plants grown under LEDs light irradiation compared to those of lettuce grown under the fluorescent light which showed higher P and Mn contents. In conclusion, it is considered that red + blue light irradiation which stimulates growth and higher nutrient uptake in leaf lettuce could be employed in containers equipped with LEDs.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.10
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• pp.1467-1476
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• 2014

Recent studies have shown that insufficient or deficient vitamin D status may be linked to increased risk of depressive conditions or depression. The aim of this study was to review all available evidence on vitamin D, depression, and any association between them. Cross-sectional, case-control, and cohort studies have reported contradictory results. Some have reported that low levels of vitamin D may be associated with higher risk of depression or depressive symptoms while others reported that vitamin D status may not be related to depression. Recent clinical trials examining the effects of vitamin D supplementation on depression have also showed discrepant results. However, meta-analysis study results are consistent regarding the beneficial effects of vitamin D. Several mechanisms that account for these beneficial effects of vitamin D on depression have been reported but remain largely speculative. Vitamin D deficiency is very common, and prevalence of depression is increasing in the Asian population, especially females. However, limited literature is available on this population. Considering research results of a potential inverse association between vitamin D level and prevalence of depression, it is important to advance our understanding of the role of vitamin D in depression and conduct well-designed prospective trials in the Asian population.

• Korean Journal of Remote Sensing
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• v.22 no.2
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• pp.141-151
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• 2006

UV-visible absorption measurement techniques using several horizone viewing directions in addition to the traditional zenith-sky pointing have been recently developed in ground-based remote sensing of atmospheric constituents. The spatial distribution of various trace gases close to the instrument can be derived by combing several viewing directions. Multi-axis differential optical absorption spectroscopy (MAX-DOAS) technique, one of the remote sensing techniques for air quality measurements, uses the scattered sunlight as a light source and measures it at various elevation angles (corresponding to the viewing directions) by sequential scanning with a stepper motor. A MAX-DOAS system developed by GIST/ADEMRC has been applied to measuring trace gases in urban air and plumes of the volcano and fossil fuel power plant in January, May, and October 2004, respectively. MAX-DOAS spectra were analyzed to identify and quantify $SO_2,\;NO_2,\;BrO,\;and\;O_4$ (based on Slant Column Densities, SCD) in the urban air, volcanic plume, and fossil fuel power plant utilizing theirs specific structured absorption features in the UV-visible region. Vertical scan through the multiple elevation angles was performed at different directions perpendicular to the plume dispersion to retrieve cross-sectional distribution of $SO_2\;or\;NO_2$ in the plumes of the volcano and fossil fuel power plant. Based on the estimated cross sections of the plumes the mixing ratios were estimated to 580 $SO_2$ ppbv in the volcanic Plume, and 337 $NO_2\;and\;227\;SO_2$ ppbv in the plume of the fossil fuel power plant, respectively.