• Journal of Environmental Health Sciences
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• v.33 no.2 s.95
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• pp.123-131
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• 2007

Many environmental contaminants including several metals, polycyclic aromatic hydrocarbons, and pharmaceuticals, have been identified to be phototoxic in the water environment. Concerns regarding photo-enhancement of toxicity of several environmental contaminants have been increasing because of the increased level of ultraviolet irradiation on the earth surface. However, there exist arguments that there might be certain defense mechanisms taking place in the aquatic ecosystem, which may include behavioral characteristics or genetic acclimation. This study was conducted to understand the potential responses of aquatic receptors to several phototoxic metals in the real environment, where long-term acclimation of such organisms to low dose UV-B may take place. For this purpose, water flea Daphnia magna was acclimated to environmentally relevant dose of UV-B (12 to $18uW/cm^2$) for >11 generations. The differences in developmental and life history characteristics, and toxicity responses were evaluated. Acclimation did not affect the daphnids' growth, longevity, and reproduction characteristics such as time to first brood, and brood size: After 21 d, survival of D. magna was not influenced by UV-B acclimation. When the number of young per female was compared. the daphnids acclimated for 11 generations tend to produce less number of neonates than the un-acclimated individuals but with no statistical significance (p>0.05). Four metals that were reported to be phototoxic elsewhere were employed in this evaluation, that include As, Cd. Cu, and Ni. UV-B level being applied in acclimation did increase the toxicity of Cd and Cu, significantly (p<0.05). However, the toxicities of As and Ni were not affected by irradiation of UV-B. Phototoxic responses were evaluated between the acclimated and the un-acclimated daphnids. For Cu, UV-B acclimation led to reduction of the photo-induced toxicity $(p\approx0.1)$ in daphnids. Non-acclimated Daphnia were affected by 50% at 4.18 ug/l Cu. but UV-B acclimated individuals exhibited $EC_{50}$ of 5.89 ug/l. With Cd, UV-B acclimation appeared to increase phototoxicity (p>0.05). With As and Ni, UV-B acclimation did not influence photo-induced toxicity. This observation may be in part explained by the type of reactive oxygen species that were generated by each metal. Similar to UV-B light, Cu is known to generate superoxide anion by acting as redox cycling toxicant. This is one of the first studies that employed_laboratory based UV-B acclimated test species for photoenhanced toxicity evaluation.

• Applied Microscopy
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• v.36 no.2
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• pp.109-118
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• 2006

The physicochemical properties of damaged hair by irradiation of ultraviolet-B (UV-B) have been investigated by using transmission electron microscope and scanning electron microscope. The range of irradiation of hair irradiated for expectative 6 hours, 12 hours, 24 hours and 48 hours with stimulated ultraviolet ray. The treated hairs showed characteristic morphological damage pattern in the cornified cell of matrix and the cuticle following time past. The various sized vacuoles in the endocuticle of the cuticular cells was formed. The statistically significant differences in diameter of cuticular cell were observed in terms of tranverse swelling by formation of vacuoles. The hair cortex and matrix undergo long term exposure to UV-B radiation. The macrofibrils of cortex appeared to be affected most by UV-B, although the morphology and volume of melanin granule was not changed. The physicochemical destruction of hair matrix and cuticular cells is largely accelerated by long term irradiation of UV-B.

• Journal of Radiation Protection and Research
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• v.32 no.2
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• pp.59-64
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• 2007

We induced the activation of melanocytes in the epidermis of C57BL/6 mice by ultraviolet B (UVB) irradiation and observed the effect of bamboo (Phyllostachys nigra var. henenis Strapf) leaf extract (BLE) on the formation, and decrease of UVB-induced epidermal melanocytes. C57BL/6 mice were irradiated by $UVB\;80mJ/cm^2(0.5mW/sec)$ daily for 7 days, and BLE was intraperitoneally or topically applied pre-or post-irradiation. For the estimation of change of epidermal melanocytes, light microscopic observation with dihydroxyphenylalanine (DOPA) stain was performed. Split epidermal sheets prepared from the ear of untreated mice exhibited 11-16 $melanocytes/mm^2$, and one week after UV irradiation, the applied areas show an increased number of strongly DOPA-positive melanocytes with stout dendrites. But intraperitoneal or topical treatment with BLE before each irradiation interrupted UVB-induced pigmentation and resulted in a marked reduction in the number of epidermal melanocytes as compared to radiation control skin. The number and size of DOPA-positive epidermal melanocytes were also significantly decreased in intraperitoneally injected or topically applicated group after irradiation with BLE at 3rd and 6th weeks after irradiation. The results of present study indicate that BLE is likely to be useful as inhibitor of UVB-induced pigmentation and depigmenting agent.

• Journal of the Korean Ceramic Society
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• v.39 no.12
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• pp.1158-1163
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• 2002

An Ge/B-doped optical fiber with high photosensitivity was fabricated to induce large second-order optical nonlinearity by UV poling. It was found that long period fiber gratings were inscribed on the fiber by the 248 nm KrF excimer laser irradiation with pulse energy of 116 mJ/$cm^2$ and pulse frequency of 10 Hz without hydrogen loading treatment. The photosensitivity was measured by use of the long period fiber grating pair method and the refractive index change of 3.3$10{\times}^{-3}$ was found to be induced in the core of the optical fiber by the KrF excimer laser irradiation of 8.67 kJ/$cm^2$. An H-shaped optical fiber was also fabricated for the UV poling through optimization of the fiber drawing condition.

• Korean Journal of Medicinal Crop Science
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• v.14 no.6
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• pp.360-366
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• 2006

To investigate the effect of culture conditions on growth and ginsenosides accumulation, we cultured the ginseng hairy root under three different media, white light or ultra-violet irradiation. The MS/B5 medium containning MS basal salt and B5 vitamin was good for the growth and ginsenoside accumulation. The light during the culture period of ginseng hairy root was irradiated. The growth was abundant in the ginseng hairy root cultured in dark. But the ginsenosides accumulation was higher than in the ginseng hairy root cultured in the light irradiation. When the ginseng hairy root was cultured in 20 L bioreactor, the ginsenosides accumulation was observed at 34% higher than the hairy root cultured in dark. UV irradiated the ginseng hairy root during the culture period. The long time irradiation of UV was caused decreasing the growth of ginseng hairy root, but the accumulation of ginsenosidess was increased as to the irradiated time.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.11
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• pp.1632-1638
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• 2012

The effects of combined treatment of aqueous $ClO_2$ and UV-C or electron beam irradiation on microbial growth and quality in chicon during storage at $4^{\circ}C$ were investigated. Samples were treated separately with 50 ppm of $ClO_2$, 5 kJ/$m^2$ of UV-C, 2, 5, 7, and 10 kGy of electron beam irradiation, as well as a combination of $ClO_2$ and UV-C or 2 kGy of electron beam irradiation. The populations of total aerobic bacteria as well as yeast and molds in the chicon samples were determined following each treatment. The populations of total aerobic bacteria in the chicon samples decreased by 1.49~2.92 log CFU/g following combined treatment of $ClO_2$ and UV-C irradiation compared to the control, whereas the populations of yeast and molds decreased by 1.63~1.78 log CFU/g. On the contrary, following combined treatment of $ClO_2$ and electron beam irradiation, the populations of total aerobic bacteria as well as yeast and molds in the chicon samples were undetectable during storage. Color measurements indicated that Hunter $L^*$, $a^*$, and $b^*$ values were not significantly different among the treatments during storage. These results suggest that combined treatment of $ClO_2$ and electron beam irradiation can be useful for improving microbiological safety in chicon during storage.

• Food Science and Preservation
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• v.16 no.5
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• pp.636-643
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• 2009

Inactivation by UV-C irradiation of Escherichia coli O157:H7 and Listeria monocytogenes inoculated onto washed carrots was examined. Carrot samples were inoculated with 6-7 log CFU/mL of E. coli O157:H7 or L. monocytogenes, treated with doses of 0, 1, 3, 5, or $10\;kJ/m^2$ UV-C, and stored at $4{\pm}1^{\circ}C$ for 8 d. The populations of E. coli O157:H7 and L. monocytogenes significantly decreased with increasing irradiation dose (p<0.05). In particular, E. coli O157:H7 and L. monocytogenes populations fell significantly by 2.35 and 2.38 log CFU/g at $10\;kJ/m^2$, respectively, compared to control values. UV-C irradiation inhibited color changes and decreased the whiteness index in carrot during storage, compared to controls. Sensory evaluation results showed that UV-C-treated carrots had better sensory characteristics than did the control. Therefore, the results suggest that UV-C irradiation could be useful to improve the microbial safety and sensory qualities of fresh-cut carrots during storage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.1
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• pp.39-44
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• 2005

This study was conducted to examine the physiological and biochemical responses against UV-B radiation in the seedling of 15 different rice cultivars, having the different physiological sensitivities. Out of 15 rice cultivars tested, moderate and susceptible groups showed significant decreases in biomass and RGR (relative growth rate). Contents of total chlorophyll were reduced remarkedly by irradiation of UV-B. In all rice cultivars tested, the content of chlorophyll a was strongly decreased, while the contents of chlorophyll b were slightly reduced without showing clear different among three groups and 15 cultivars. Carotenoid content was largely reduced by UV-B radiation, whereas polyamine content was moderately increased. The contents of MDA (malondialdehyde) that reflect the level of lipid peroxidation of cell membranes were clearly increased by UV-B stress, showing higher content in susceptible cultivars than moderate and torelant cultivars. The physiological important parameters highly related to visible injury were leaf color, chlorophyll, carotenoid, and lipid peroxidation, whereas biomass and polyamines were not closely correlated. Based on this results, it was concluded that changes of visible injury and the contents of chlorophyll and MDA could be adequately applied and utilized as physiological indicators to UV-B radiation.

• Food Science and Preservation
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• v.15 no.6
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• pp.922-926
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• 2008

The effect of UV-C irradiation on microbial growth and the quality of imported dried filefish and octopus during storage was examined. Samples of imported dried filefish and octopus were irradiated at 0, 5, 10 and $20\;kJ/m^2$ and stored for 3 months at $20^{\circ}C$ or for 6 days at $4^{\circ}C$. Exposure times of 5 min 33 sec, 11 min 6 sec, and 22 min 12 sec were used. UV-C treatment of the imported dried filefish and octopus decreased the populations of aerobic bacteria, yeasts and molds in proportion to radiation dose. Compared to the control, total aerobic bacteria, and yeast and mold populations were significantly lower (1-2 log CFU/g) with UV-C treatment of $20\;kJ/m^2$. UV-C irradiation caused negligible changes in the Hunter color L, a and b values. These results indicate that UV-C irradiation could be useful in inhibiting microbial growth on imported dried fish without impairing quality during storage.

• Journal of the East Asian Society of Dietary Life
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• v.22 no.2
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• pp.224-230
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• 2012

To investigate the effect of Panax ginseng C.A. Meyer extract (Ginseol K-b1), on skin functionality, we evaluated skin appearance and properties, such as wrinkle formation, skin moisture content, and skin elasticity in the skin of hairless mice damaged by UV irradiation. In addition, the effect of Ginseol K-b1 on collagen synthesis in human dermal fibroblasts was investigated. Female hairless mice were orally administered Ginseol K-b1 for 10 weeks with UV irradiation. Wrinkle formation in the Ginseol K-b1-treated group was significantly suppressed compared to the UV-irradiated group. Skin properties, including skin moisture content and elasticity, of the Ginseol K-b1-treated group were better than those of the control group. In the human fibroblast cells, Ginseol K-b1 treatment enhanced cell proliferation and significantly stimulated collagen synthesis. These results suggest that Ginseol K-b1 is a potent ingredient with anti-aging effects.