• Journal of Ginseng Research
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• v.10 no.2
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• pp.193-199
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• 1986

To investigate the stability of ginseng saponin, various physical and chemical treatments for red ginseng alcohol extract (70% ethyl alcohol) were carried out, and then the variations of ginseng saponin in extract were investigated by high performance liquid chromatography (HPLC) method. Irradiation of ${\gamma}$-ray, and ultraviolet ray, sonocatalysis by ultrasonicator, treatment of electronic range, catalytic ozonation did not or slightly affect degradation of ginseng saponins, but they were degraded by heat treatment.

• Journal of the Korean Graphic Arts Communication Society
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• v.10 no.1
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• pp.1-13
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• 1992

The recent results concerning the synthesis and application of spiroxazine dyes have been summerized., The absorption bands of usual spiroxazine dyes are changed from colorless to colored from by irradiation of ultraviolet ray. This mechanism is derived from the cleavage of oxazine ring. Such properties are dependent on its chemical structure and surrounded matrix of spiroxazine dyes. the chemical structure of this dye is similar to the well known spriopyran. But spiroxazine dyes have noticed recently, because of excellent high light-sensitivity and superior fatigue-resistant property. This dye are already applied as photochromic lens, cloths and UV light checker.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.627-630
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• 2002

Bi$_2$Sr$_2$CuOx(Bi-2201) thin films were fabricated by atomic layer-by-layer deposition using an ion bean sputtering method. 10 wt% and 90 wt% ozone mired with oxygen were used with ultraviolet light irradiation to assist oxidation. XRD and RHEED investigations revealed that a buffer layer is formed at the early stage of deposition (less than 10 unit cell), and then c-axis oriented Bi-2201 grows on top of it.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.231.1-231.1
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• 2003

Ultraviolet (UV) irradiation is well known to cause human skin aging and skin cancer through activation of matrix metalloproteinases (MMPs) which are responsible for the degradation of collagen, an extracellular matrix component. However, the molecular mechanisms of UV-induced MMP expression are yet to be defined. In this study, we investigated signaling molecules involved in UV-induced MMP expression in HaCaT human keratinocytes. (omitted)

• Journal of Photoscience
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• v.9 no.2
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• pp.205-208
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• 2002

Nitric oxide (NO) is a newly described transmitter involved with cell to cell communication that is generated in biologic tissues by specific types of nitric oxide synthase (NOS), which metabolize L-arginine and molecular oxygen to citrulline and nitric oxide. In the skin. NO has been reported to play an important role in such diseases as psoriasis, atopic dermatitis, and contact dermatitis, as well as act as an important modulator in UVB-induced erythema. Ultraviolet B irradiation to the skin evokes an increase in NO production in the epidermis through two pathways; induction of inducible NOS, mediated by inflammatory cytokines, and elevation of constitutive neuronal NOS activity. In a cell culture system, it has been demonstrated that NO functions as a melanogen after being produced in keratinocytes in response to UVB-irradiation. NO-stimulated melanogenesis in melanocytes is mediated by the cGMP/PKG pathway. In this study, up-regulation of tyrosinase gene expression by NO-stimulation and the involvement of NO in UVB-induced pigmentation were examined. In NO-induced melanogenesis, protein synthesis and tyrosinase activity increased along with an up-regulation of tyrosinase gene expression. In an animal model, UVB-induced pigmentation in skin was suppressed by sequential daily treatments with a specific inhibitor of NOS. Thus, NO plays an important role in UVB-induced pigmentation, where its function as a melanogen is considered to be one of the mechanisms. Together with its role in the development of erythema, NO contributes to the total protective response of skin against UVB-irradiation.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1765-1767
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• 1999

We synthesised a photo-alignment material of PM4Ch (poly(4-methacryloylloxychalcone)). The electro-optical (EO) characteristics of photo-aligned twisted nematic (TN)-liquid crystal display (LCD) with linearly polarized ultraviolet (UV) light irradiation on PM4Ch surface were investigated. The uniform alignment of NLC with polarized UV light irradiation on PM4Ch surface was measured. Also, We had The excellent voltage-transmittance characteristics of photo-aligned TN-LCD. The low threshold voltage of photo-aligned TN-LCD was measured. Moreover, the fast response time of photo-aligned TN-LCD on PM4Ch was successfully achieved. Finally The reduction DC voltage of photo-aligned TN-LCD decreases with increasing the UV light irradiation time on photo-dimerized PM4Ch surface.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1759-1761
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• 1999

The generation of pretilt in nematic liquid crystal(NLC)and electro-optical(EO) characteristics of photo-aligned twisted nematic (TN)-LCD with oblique p-polarized ultraviolet (UV) light irradiation on the two kinds of the soluble polyimide (PI) surfaces containing trifluoromethyl moieties were investigated. The generated pretilt angle of NLC is about $2.5^{\circ}$ with p-polarized UV light irradiation of $20^{\circ}$ on PI-3 surface at 20 min.; However pretilt angle of about $0.5^{\circ}$ are observed on PI-1 and PI-2 surfaces. The generated pretilt angle of NLC on PI-3 surface may be attributed to the trifluoromethyl moieties attached to the lateral benzene rings. The voltage-transmittance and response time characteristics of photo-aligned TN-LCD with p-polarized UV light irradiation of $20^{\circ}$ on PI-1 surfaceat at 20 min were almost same in comparison with the rubbing-aligned TN-LCD. However, the high threshold voltage and slow response are observed on PI-3 surface. Also, the decay time $\tau_d$ of photo-aligned TN-LCD is attributed to the anchoring energy of NLC.

• Journal of the Korean Applied Science and Technology
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• v.19 no.1
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• pp.43-48
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• 2002

We carried out this subject to observe photoisomerization using 1,2-dioleoyl-sn- glycero-3-phosphocholine(DOPC) mixed with fatty acid containing azobenzene group which has reversible to cis-trans by light irradiation. Spreading solutions for the LB films were prepared in chloroform($5.0{\times}10^{-5}$mol/L).We investigated the photoisomerization and property of the organic ultra thin film of fatty acid containing azobenzene was prepared on the hydrophilic ITO(idium tin oxide) glass plate by LB method. As a result, the absorption spectra of 8A5H and DOPC of mixture LB films was induced to photoisomerization by alternating irradiation of ultraviolet and visible light, because the condensation of pure azobenzene monolayers was loosened by the introduction of phospholipid into the monolayers, and the molecular high aggregation in pure azobenzene monolayers is also weakened by the introduction of phospholipid. We found that it was reversibly induced to cis-trans photoisomerization in several solvents and mixture LB films.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.343-346
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• 1998

The generation of pretilt angle in nematic liquid crystal (NLC) and electro-optical (EO) characteristics of photo-aligned twisted nematic (TN)-LCD with oblique P-polarized ultraviolet (UV) light irradiation on the two kinds of the soluble polyimide (PI) surfaces containing trifluoromethyl moieties were investigated. The generated pretilt angle of NLC is about 2.5$^{\circ}$with P-polarized UV light irradiation of 20$^{\circ}$on PI-3 surface at 20 min.; However pretilt angle of about 0.5$^{\circ}$are observed on PI-1 and PI-2 surfaces. The generated pretilt angle of NLC on PI-3 surface may be attributed to the trifluoromethyl moieties attached to the lateral benzene rings. The voltage-transmittance and response time characteristics of photo-aligned TN-LCD with P-polarized UV light irradiation of 20$^{\circ}$on PI-1 surface at 20 min were almost same in comparison with the rubbing-aligned TN-LCD. However, the high threshold voltage and slow response are observed on PI-3 surface. Also, the decay time $\tau$$\sub$d/ of photo-aligned TN-LCD is attributed to the anchoring energy of NLC.

• Biomolecules & Therapeutics
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• v.20 no.2
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• pp.201-206
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• 2012

Ultraviolet (UV) A penetrates deeply into the skin and induces the generation of reactive oxygen species (ROS) causing damage to fibroblasts, which leads to aging of the skin. However, the body has developed an antioxidant defence system against the harmful effects of ROS. Enzymes such as superoxide dismutase (SOD) and catalase (CAT) play critical roles on the removal of excess ROS in living organisms. In this study, the antioxidant activities of anthocyanins (cyanidin 3-galactoside and cyanidin 3-lathyroside) from Acanthopanax divaricatus var. albeofructus (ADA) fruits were investigated by xylenol orange, thiobarbituric acid reactive substances (TBARS), and antioxidant enzyme assay. As a result, generation of $H_2O_2$ and lipid peroxide induced by UVA-irradiation in human dermal fibroblast (HDF-N) cells was reduced by treatment of anthocyanins. Also, augmented enzyme (SOD and CAT) activities were observed in UVA-irradiated cells when treated with anthocyanin. In conclusion, the results obtained show that anthocyanins from ADA fruits are potential candidates for the protection of fibroblast against the damaging effects of UVA irradiation. Furthermore, anthocyanin may be a good candidate for antioxidant agent development.