• Journal of Nutrition and Health
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• v.45 no.3
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• pp.211-217
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• 2012

UV-irradiation is a major factor of photo-aged skin, by which pigmentation, wrinkles and laxity are increased. In addition, the epidermal barrier is disrupted, ultimately causing dryness in photo-aged skin. As an effort to search dietary sources for improving the dryness of UV irradiated skin, the dietary effect of red ginseng based functional foods on the epidermal level of ceramides, a major lipid maintaining epidermal barrier, was determined in this study. Albino hairless mice were fed either a control diet [group UV (UV-irradiated control)] or diets with 0.5% (group M0.5) or 1% (group M1.0) of red ginseng extracts mixed with Torilis fructus and Corni fructus (66.7% red ginseng) in parallel with UV irradiation for 5 wks. A normal control group (group C) was fed a control diet without UV irradiation for 5 wks. The epidermal level of ceramides in group UV was significantly lower than that in group C, in which ceramidase, an enzyme involved in ceramide degradation, was highly expressed. In group M0.5, the epidermal level of ceramide was significantly increased to the level even higher than in group C. In addition, protein expression of serine palmitoyl transferase (SPT), a key enzyme involved in de novo ceramide synthesis, was increased in group M0.5. However the epidermal levels of ceramides as well as of ceramidase protein expression in group M1.0 did not differ from those in group UV. In conclusion, we demonstrate that dietary supplementation of red-ginseng extracts mixed with Torilis fructus and Corni fructus at a level of 0.5% level in diet increased the epidermal level of ceramides coupled with the elevated expression of SPT protein.

• Journal of the Korean Applied Science and Technology
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• v.4 no.1
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• pp.19-22
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• 1987

To investigate the protective action of various antioxidants on the photooxidation of rice bran oil, it was irradiated with red and visible light in presence and absence antioxidants with or without sensitizer (methylene blue). 1. Rice bran oil with and without sensitizer in chloroform-ethanol (4:1, v/v) media was largely oxidized under visible light irradiation. on the other hand, rice bran oil without sensitizer was hardly oxidized under red light irradiation. 2. Rice bran oil with sensitizer was oxidized much faster than that without. And the absorbance of it irradiated with visible was increased more than that with red light. 3. The effectiveness of antioxidants on the rice bran oil photooxidation was same order as follows: Irradiation with visible light, no addition of sensitizer ${\beta}$-carotene > dl-{$\alpha}$-tocopherol > BHT > BHA Irradiation with visible light, addition of sensitizer ${\beta}$-carotene > BHT > dl-${\alpha}$tocopherol > BHA Irradiation with red light, addition of sensitizer ${\beta}$-carotene > BHA > BHT > dl-${\alpha}$-tocopherol From these results, we concluded that rice bran oil was largely oxidized under visible light irradiation, therefore it must be protected from photooxidative deterioration by the addition of antioxidants.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.6
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• pp.477-480
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• 1998

In this paper, we investigated the liquid crystal(LC) alignment and generation of pretilt angle by using photo-alignment techniques on two kinds of polyimide(PI) surface, It was found that the uniform alignment for nematic(N) LC is obtained in a cell with slanted UV light irradiation on PI surface without side chain. We successfully observed that the pretilt angle of NLC is generated about $3^{\circ}$ with an incident angle of 70 degree on the PI surface without side chain. It is considered that the pretilt angle generation in NLC is attributed to interaction between the LC molecules and the polymer surfaces.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.12
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• pp.1160-1166
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• 2006

Maxwell-displacement-current (MDC) measuring technique has been applied for the investigation of monolayers of poly(vinyl alcohol)s bearing azobenzene side-chains (6Az5PVA) mixed with p-pentyl-p'-cyano-biphenyls (5CBs) on a water surface. For mixed monolayers containing trans-form 6Az5PVA and LCs, displacement current due to photo isomerization was not generated with alternative photo-irradiation with UV and svisible light. In contrast, for mixed monolaters containing cis-form 6Az5PVA and LCs, displacement current was generated. Finally, it was found that the alignment layers deposited in cis-form could photoregualte the orientation of LCs.

• Bulletin of the Korean Chemical Society
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• v.29 no.4
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• pp.827-832
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• 2008

A new diarylethene compound with donor and acceptor substituent was synthesized from 2,3-bis(2-methylbenzo[b]thiophene-3-yl)hexafluorocyclopentene (BTF) over 5 steps. The donor-acceptor structured BTF compound (TBTFE) showed spectral change to a longer wavelength through photochromism with a high cyclization quantum yield (0.56). The 3,4-ethylenedioxythiophene (T) and carboethoxy (E) groups directly connected to BTF unit promoted electrical change accompanied with the photoisomerization of the BTF unit. Photo-induced electrical switching was achieved from a photocell containing TBTFE doped polymer film, which showed reversible and stable current change over repeated cycles by the alternative UV/Vis irradiation, as estimated by the I-V plot.

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.08a
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• pp.152.2-152
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• 1998

• Proceedings of the Korean Magnestics Society Conference
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• 2016.11a
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• pp.118-118
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• 2016

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.10 no.1
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• pp.55-62
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• 2004

Synthesis of poly[N-(formyloxyphenyl)maleimide](PFOMI) as photopolymer were investigated with various kinds of photosensitive groups. Generally, photopolyimide have some deficiencies in solubility, sensitivity, reserve stability of the photosensitive solution, and the precision of image pattern. The study has been required on those polymers which have high glass transition temperature and photo efficiency, and low dielectricity. The existing condensation resins require high curing temperature and perfect elimination of subreacted materials that are produced during the process after irradiation and various membrane damages such as the deformation and contraction in image pattern cure. In this study poly[N-(hydroxyphenyl)maleimide](PHPMI) was synthesized. The PHPMI were analyzed by H-NMR and FT-IR. The measured number average molecular weight of PHPMI was produced was $1.06{\times}10^4$. Poly[N-(formyloxyphenyl)maleimide](PFOMI) as a type of photo-Fries rearrangement was synthesized by NHPMI and formic acid followed by radical polymerization. PFOMI was analyzed by FT-IR, and photocharacteristics was investgated by UV spectra and FT-IR before and after UV irradiation. Based on the image characteristics of PFOMI measured from optical micrographs, it was formed that the resolution of positive type PFOMI was $0.5{\mu}m$.

• Journal of Electrical Engineering and Technology
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• v.8 no.5
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• pp.1169-1174
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• 2013

The objective of this work was to increase the efficiency of ultraviolet-light emitting diodes at 375 nm for sterilization. Since $TiO_2$ had antibacterial properties, which were attributed to the appearance of hydroxyl radicals and superoxide radical anions on the surface species under ultra violet radiation at about 387 nm, photo-reactive layers such as Ag-doped $TiO_2$ were coated on aluminum substrates by electrostatic spraying. Crystallinity and surface morphology of the coating layer were examined by X-ray diffraction ${\theta}-2{\theta}$ scan and field emission-scanning electron microscope, respectively. In an antibacterial test, we observed above 99% reduction of Escherichia coli populations on 3 or 5 mol% Ag-doped $TiO_2$ layers after irradiation for 2 hrs at 375 nm, while very low inactivation on bare aluminum substrates occurred after irradiation as the same condition.

• Journal of the Optical Society of Korea
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• v.18 no.6
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• pp.753-761
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• 2014

We propose a two-step UV irradiation procedure to fabricate polymer-dispersed liquid crystal (PDLC) films by lamination. During the first UV treatment, before lamination, the UV-curable monomers coated on one film substrate are solidified through photo-polymerization as the phase separation between the liquid crystals and the monomers. Introducing an adhesion-enhancement layer on the other plastic substrate and controlling the UV irradiation conditions ensure that UV-induced cross-linkable functional groups remain on the surfaces of the photo-polymerized layers. Thereby, the adhesion stability between the top and bottom films is much improved during a second (post-lamination) UV treatment by further UV-induced cross-linking at the interface. Because the adhesion-enhancement and PDLC layers prepared by the bar-coating process are solidified before lamination, the PDLC droplet distribution and the cell gap between the two plastic substrates remain uniform under the lamination pressure. This ensures that the voltage-controlled light transmittance is uniform across the entire sample.