• Journal of Photoscience
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• v.9 no.2
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• pp.236-239
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• 2002

Sunscreens have been advocated as an important means of preventing skin cancer. UV-induced immunosuppression is important for skin cancer development, yet the effectiveness of sunscreens in protecting the human immune system from UV radiation is unclear. The only currently accepted method of sunscreen rating is the Sun Protection Factor (SPF) based on prevention of erythema. We developed an in vivo non-invasive method for evaluating protection of the human immune system from UV radiation based on recall contact sensitivity to nickel, a common allergen. Using this system we showed that broad-spectrum sunscreens provide greater protection to the immune system than sunscreens which protect from UVB only. UVA was found to be immunosuppressive. We developed this technique to enable the study of solar simulated UV radiation dose responses and determined Immune Protection Factors (IPFs) for six commercially available sunscreens based on limits of protection from the dose response data. We found that the IPF did not correlate with the SPF and that protection from erythema therefore cannot be used to predict protection of the immune system. However, IPF was significantly correlated to the UVA protective capability of the sunscreens, indicating that sunscreen protection from UVA is important for prevention of immunosuppression. We recommend that sunscreens should be rated against their immune protective capability to provide a better indication of their ability to protect against skin cancer.

• Journal of the Korean Applied Science and Technology
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• v.23 no.2
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• pp.153-159
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• 2006

The photocatalytic degradation of methylene blue(MB) was investigated using $TiO_2$ as photocatalyst and UV radiation. $TiO_2$ supported with activated carbon(AC) was prepared by SOL-GEL method and depended on several parameters such as the mass ratio of $TiO_2/AC$, pH and experimental time. The presence of the anatase and rutile crystal phase was determined by XRD analyses of the prepared $TiO_2$. The degradation of MB with $TiO_2/AC$ was about 20% higher than that of AC alone. A variation of photodegradation was negligible under UV radiation conditions ( ${\geq}$ 40W). It was experimentally showed that the photodegradation rate was increased with increasing the amount of photocatalyst. The optimal catalyst was prepared by impregmation of $5wt%-TiO_2$ with AC and was calcined at $300^{\circ}C$, and showed about 99% removal efficiency for 3hrs.

• Journal of Radiation Protection and Research
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• v.33 no.3
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• pp.87-91
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• 2008

We induced the activation of melanocytes in the epidermis of C57BL/6 mice by ultraviolet B (UVB) irradiation and observed the effect of Bu-Zhong-Yi-Qi-Tang (BZYQT) on the formation, and decrease of UVB-induced epidermal melanocytes. C57BL/6 mice were irradiated by UVB $80\;mJ/cm^2$ (0.5 mW/sec) daily for 7 days, and BZYQT 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 BZYQT 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 BZYQT at 3rd and 6th weeks after irradiation. The present study suggests the BZYQT as inhibitor of UVB-induced pigmentation and depigmenting agent.

• Journal of Radiation Protection and Research
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• v.36 no.2
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• pp.93-98
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• 2011

We induced the activation of melanocytes in the epidermis of C57BL/6 mice by ultraviolet-B (UV-B) irradiation, and observed the effect of an herbal preparation (HemoHIM, HH) on the formation, and decrease of UV-B-induced epidermal melanocytes. C57BL/6 mice were irradiated by UV-B $80\;mJ{\cdot}cm^{-2}$ ($0.5\;mW{\cdot}sec^{-1}$) daily for 7 days, and HH was intraperitoneally, orally 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 13~15 melanocytes${\cdot}mm^{-2}$, and one week after UV irradiation, the applied areas showed an increased number of strongly DOPA-positive melanocytes with stout dendrites. But intraperitoneal, oral or topical treatment with HH before each irradiation interrupted UV-B-induced pigmentation and resulted in a marked reduction in the number of epidermal melanocytes as compared to the number found in UV-B-irradiated, untreated 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 HH at 3rd and 6th weeks after irradiation. The present study suggests the HH as inhibitor of UV-B-induced pigmentation, and depigmenting agent.

• Bulletin of the Korean Chemical Society
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• v.32 no.spc8
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• pp.3039-3044
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• 2011

This study suggests the prediction model for the concentration variation of $NO_2{^-}$ and $NO_3{^-}$ along with the rate constants of all reactions during ozonation under UV radiation ($O_3$/UV process). While $NO_2{^-}$ was completely converted into $NO_3{^-}$ during the $O_3$-only process, the production of $NO_2$ radical or $N_2O_4$ was expected in the $O_3$/UV process. In addition, the quenching of OH radicals, by $NO_2$ radical in the $O_3$/UV process, resulted in regeneration of $NO_2{^-}$. However, the regeneration of $NO_2{^-}$ was not observed in the $O_3$/UV process in the presence of $C_6H_6$ where the concentrations of $NO_2{^-}$ and $NO_3{^-}$ were significantly reduced compared to in the process without $C_6H_6$. The pseudo-first order rate constants of all species were calculated with and without the presence of $C_6H_6$ to predict the variation of concentrations of all species during the $O_3$/UV process. It was suggested that $NO_2{^-}$ and $NO_3{^-}$ in the $O_3$/UV process can be more effectively removed from an aqueous system with an OH radical scavenger such as $C_6H_6$.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.103-106
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• 2003

In this work the novel potential epoxy resins, were synthesized and acrylated. Their structures were confirmed by means of FTIR, $^1H NMR, and^{13}/C NMR$ spectroscopies. Also, we were to note the effect of W curing on functional group changes of VE/UP blend system after UV curing.

• The Korean Journal of Food And Nutrition
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• v.36 no.1
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• pp.17-24
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• 2023

To apply UV-C as a non-heating sterilization method to increase the microbiological safety of fresh seedless watermelon products, reductions in E. coli and quality changes by treatment dose (0, 2, 4, 8, 14, 20 kJ/m²) were investigated. The pH, sugar content, and hardness of watermelon inoculated with E. coli were not significantly different according to the UV-C treatment dose, but the polyphenol content was significantly decreased compared to the controls (425.4 GAE ㎍/g F.W.). When treated with 2 and 4 kJ/m², the lycopene content was 31.6 and 30.9 ㎍/g F.W., respectively, which was increased compared to the controls (28.5 ㎍/g F.W.). The arginine and citrulline content was also significantly increased compared to the controls. The number of E. coli was significantly decreased compared to the controls following UV-C treatment. Considering the degree of E. coli reduction, lycopene content, arginine content, citrulline content, and UV-C irradiation time, subsequent experiments were conducted by selecting a UV-C treatment dose of 2 kJ/m². The results of confirming the degree of reduction in the number of E. coli colonies by a single treatment and combined treatment with UV-C 2 kJ/m² and 70% ethanol showed that the combined treatment was most effective as colonies were decreased by 2.3 log CFU/g compared to the controls. Therefore, it is judged that UV-C 2 kJ/m² radiation and combined treatment with 70% ethanol could be applied as a non-heating sterilization method for fresh watermelon slices.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.794-798
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• 2003

The reactive oxygen species (or free radicals) generated by ultraviolet radiation cause damage on cellular components and pigment of skin. The aim of this study was to investigate the skin-whitenig effect of Okyong-san. Inhibitory effects of okyong-san extracts on melanin synthesis were studied. Namely, UV-absorbing ability, free radical scavenging activity and tyrosinase inhibitory activity of okyong-san extracts were investigated. As a result, the extracts of okyong-san were found to inhibit the activity of tyrosinase and they showed an absorbance in the UV-B region and UV-C region. We also observed that extracts of okyong-san had free radical scavenging activity.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.73.2-73.2
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• 2019

Understanding how ionizing radiation propagates from molecular clouds to the intergalactic space is the key to the study of reionization and the emergence of $Ly{\alpha}$ emission from galaxies. In this contribution, I will present our new efforts to better understand the escape of UV photons from turbulent clouds with different masses, star formation efficiencies, and spectral energy distributions using radiation-hydrodynamic simulations. I will also show predicted Lya profiles from turbulent clouds and discuss a few interesting differences identified when compared with the properties of the local green pea galaxies.

• Journal of Marine Bioscience and Biotechnology
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• v.6 no.2
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• pp.131-137
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• 2014

Ultraviolet-B radiation (UV-B) in sunlight causes biological damages such as erythema and blister on skin. Microalgae have been in the limelight as an attractive feedstock for manufacturing functional materials. This study focused on screening microalga with protection ability against UV-B. The microalgae were isolated from local areas on April to June 2013 as well as June 2014. The cells were grown under continuous illumination from fluorescent lamps at $136.3{\pm}2.2{\mu}E/m^2/s$ in BG-11 medium at $15^{\circ}C$ for 12-14 days. The selected cells were spread on BG-11 agar and were exposed to UV-B (312 nm) for 20 and 25 minutes. The 13 strains among selected algae were classified. Among these, 9 strains were Scenedesmus sp. and the remains were Chlorella sp. Based on this study, it seems that Scenedesmus sp. and Chlorella sp. have resistibility against ultraviolet. These results will help to study on UV protection using microalgae.