• Journal of the Optical Society of Korea
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• v.17 no.4
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• pp.344-349
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• 2013

This paper proposes a simulation algorithm to assess the gradual yellowing vision of the elderly, which refers to the predominance of yellowness in their vision due to aging of the ocular optic media. This algorithm employed the spectral transmittance property of a yellow filter to represent the color appearance perceived by elderly people with yellow vision, and modeled the changes in the color space through a spectrum change in light using the yellow filter effect. The spectral reflectivity data of 1269 Munsell matte color chips were used as reference data. Under the standard conditions of a D65 illuminant and a $10^{\circ}$ observer of 1964 CIE, the spectrum of the 1269 Munsell colors were processed through the yellow filter effect to simulate yellow vision. Various degrees of yellow vision were modeled according to the transmittance percentage of the yellow filter. The color differences before and after the yellow filter effect were calculated using the DE2000 formula, and the color pairs were selected based on the color difference function. These color pairs are distinguishable through normal vision, but the color difference diminishes as the degree of yellow vision increases. Assuming 80% of yellow vision effect, 17 color pairs out of $(1269{\times}1268)/2$ pairs were selected, and for the 90% of yellow vision effect, only 3 color pairs were selected. The result of this study can be utilized for the diagnosis system of gradual yellow vision, making various types of test charts with selected color pairs.

• Architectural research
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• v.18 no.3
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• pp.83-90
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• 2016

Senescent effects are the gradual deterioration of function caused by biological aging. Senescent effects on color vision are not clearly understood even after considerable researches. Part of the reason is that the color vision is a complex phenomenon resulting from various factors such as organic systems, and the physical (neuro-optical) and the psychological (experiential) processes of color perception. We performed a field experiment on color perceptional differences due to aging vision. Our experiment was applied to two different groups in South Korea: an experimental group (46 subjects of over the age of 61 years) and a control group (49 subjects in their twenties). The experimental tools are comprised of (1) six gradual yellowing detector board (40%, 50%, 60%, 70%, 80%, 90%); (2) pairs of vivid-strong, vivid-deep, grayish-deep, deep-dull, and bright-light tones of Blue (B) and Purple (P) colors; (3) Red (R), Yellow (Y), Green (G), Blue (B), and Purple (P) colors of dull-tones and pale-tones; and (4) a questionnaire on the semantic differential scales of the color images and color differences. A diagnosis system of gradual yellow vision, developed by the authors for this study, was adapted to generate the color detecting boards. The results are as follows. (1) There are significant differences between the two groups in detecting colors that simulate 40% and 50% of yellow vision. (2) As to the color difference detecting ability between similar tones, the experimental group shows difficulties in pairs of vivid-strong tones and deep-dull tones of the B color. And (3), the emotional responses to the dull tone and the pale tone are not stable in the red, the yellow, blue, and purple. Thus, we empirically demonstrate the specific differences in color perception between the old and young groups.

• The Plant Pathology Journal
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• v.19 no.3
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• pp.184-187
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• 2003

Verticillium wilt was first observed in 2001 on potatoes (Solanum tuberosum) cv. Superior at Daegwallyong area, one of the major seed potato producing areas in Korea. The wilted potato plants showed typical symptoms including gradual yellowing and interveinal necrosis. There was discoloration in the vascular tissues of the infected stems which turned light brown. Fungal isolates from discolored vascular tissues were whitish to creamy with folding on potato dextrose agar medium, where they used to produce resting dark mycelia but no micro-sclerotia. Conidiophores were septate with side branches, swelled at the base, and arranged in a whorl. Conidia were 2.5-11.2$\times$2.0-4.5 $\mu\textrm{m}$ um in size and were borne in small clusters at the tips of phialides. Optimal temperature range for mycelial growth was $25-30^{\circ}C$. Based on these cultural and morphological characteristics, the fungus was identified as Verticillium albo-atrum Reink & Berth. Pathogenicity tests by root dipping method revealed that the fungus caused the same symptoms as observed in naturally infected potato plants. This is the first report of Verticillium wilt on potato caused by Verticillium albo-atrum in Korea.

• The Plant Pathology Journal
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• v.16 no.3
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• pp.156-161
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• 2000

A wilt disease occurred on greenhouse-grown eggplants at Yeojoo, Korea in 1997. The wilted eggplants had leaves with gradual yellowing, interveinal necrosis, and marginal crinkling. Vascular tissues of diseased stems were discolored, turned black, and microsclerotia developed at the base of stems. The disease progressed from lower parts of the plants upward. Fungal isolates from discolored vascular tissues were initially whitish to cream color on potato-dextrose agar (PDA) plate, which later turned black due to the formation of microsclerotia. Conidiophores were erect, hyaline, verticillately branched, and had 3 or 4 phialides arising at each node. Phialides were hyaline, arranged in whorls, and measured as 17.5-32.5 x 2-3$\mu\textrm{m}$. Conidia were hyaline, ellipsoidal to sub-cylindrical, mainly one-celled, and measured as 5-8.8 x 2-4$\mu\textrm{m}$. Conidia were borne in small clusters at the tips of phialides. Microsclerotia formed on PDA plates, and consisted of globular cells that formed irregular masses of various shapes. Chlamydospores were absent. Based on these cultural and morphological characteristics, the fungus was identified as Verticillium dahliae Klebahn. Pathogenicity tests by root cutting, root dipping or soil drenching resulted in similar symptoms observed in the naturally infected eggplants. This is the first report on occurrence of Verticillium wilt of eggplant in Korea.

• Journal of The Korean Society of Grassland and Forage Science
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• v.43 no.2
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• pp.109-115
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• 2023

Ammonium (NH₄⁺) serves as a nitrogen source, but its elevated levels can hinder plant growth and production. Excess NH₄⁺ with α-ketoglutarate is assimilated into glutamate, a precursor of proline and glutathione (GSH). This study aimed to investigate the effects of excessive NH₄⁺ on the regulation of proline and GSH synthesis. Detached leaves from oilseed rape (Brassica napus L.) were fed with 0, 50, 100, 500, and 1000 mM NH₄Cl for 16 h. As the NH₄⁺ concentrations increased, the leaves exhibited progressive wilting and yellowing. Furthermore, total carotenoid and chlorophyll concentrations declined in response to all NH₄⁺ treatments, with the lowest levels observed in 1000 mM NH₄⁺ treatment. Hydrogen peroxide (H₂O₂) concentration showed a minor increase at low NH₄⁺ concentration (50 and 100 mM) treatments but a significant increase at high NH₄⁺ (500 and 1000 mM), which was consistent with the localization of H₂O₂. Amino acid concentrations increased with increasing in NH₄⁺ concentration, while the protein concentration displayed the opposite trend. Proline and cysteine concentrations exhibited a gradual increase in response to increasing NH₄⁺ concentrations. However, GSH concentrations rose only in the 50 mM NH₄⁺ treatment and decreased in the 500 and 1000 mM NH₄⁺ treatments. These results indicate that excessive NH₄⁺ is primarily assimilated into proline, while GSH synthesis is adversely affected.