• Journal of Photoscience
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• v.9 no.2
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• pp.491-493
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• 2002

Erythrodermic actinic reticuloid (EAR) is a photosensitive disorder characterized by dense lymphocytic infiltration in the sun-exposed areas and an increased number of atypical lymphocytes in the peripheral blood. We have reported 2 patients with EAR with circulating atypical lymphocytes and photosensitivity to both ultraviolet (UV) B and A. Although no clonal proliferation of T-cells was observed in the peripheral blood, CD8+ cells were increased in number in an oligoclonal fashion. A number of proliferating CD8+ cells were small, but most cells expressed bcl-2. These findings suggest EAR is a photosensitivity dermatitis characterized by the overspill of oligoclonal CD8+ lymphocytes responsive to UV irradiation.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1167-1168
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• 2004

Polarized ultraviolet irradiation techniques have been developed recently to produce alignment of liquid crystals (LC). Because of the excellent thermal stability and the alignment ablility of polyimides, polyimides has attracted considerable research interest for the photoinduced alignment layer. Hasegawa and Taira confirmed homogeneous alignment of LC by the decompostion of a polyimide induced by lineraly ultra-violet polarized light. It was reported that ultraviolet visible absorption spectra of a polyimide alignment film showed a remarkable change upon irradiation. In this study, we synthesized phthalic polyimide and a naphthalenic polyimide in order to investigate the effect of the polyimide structure. Some difference in terms of the photo-induced molecular orientaion of liquid crystals were observed with the polyimide structure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.6
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• pp.481-485
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• 1998

We investigated the generation of high pretilt angle for nematic liquid crystal (NLC) in a cell with obilique non-polarized ultraviolet (UV) light irradiation on mixtured polyimide surface. It was found that the monodomain alignment of NLC is obtained with an angle of incidence of 75∼85 degrees on PI surface. We consider that the monodomain alignment of NLC is attributed to anisotropic dispersion force effect to photo-depolymerization of polymer. We successfully observed that the pretilt angle of NLC is generated above 5 degree with an angle of incidence of 75∼85 degrees. It is considered that the pretilt angle generation NLC is attributed to interaction between the LC molecules and the polymer surfaces.

• Journal of Plant Biology
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• v.22 no.3
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• pp.85-91
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• 1979

Tolerance against mercuric chloride in mutants of Pyricularia oryzae Cavara induced by ultraviolet(UV) irradiation has been investigated. The tolerant isolates obtained using ultraviolet(UV) irradiation were maintained a high level of tolerance even after 15 times transfer to the chemical free media. Each isolate of mutants UM-1, UM-2, and UM-3 on the successive monoconidial culture has genetically homogeneous for tolerance. The tolerant isolates sporulated less and showed a higher percentage of germination of conidia on media without the chemical than the parental isolate. The xotins released from the parental and the tolerant isolates have been identified as piricularin and $\alpha$-picolinic acid by paper-chromatography. The tolerant isolates produced more piricularin and its virulence on seedlings of rice varieties were higher than the parental isolates. Both piricularin production and virulance on rice were highest in the UM-2 isolate.

• Microbiology and Biotechnology Letters
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• v.14 no.4
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• pp.299-304
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• 1986

The cell volume, cell surface, cell concentration, dry cell weight, frequence of respiratory deficient mutation, resistance against ultraviolet irradiation, fermentation power, DNA contents of haploid diploid, triploid and tetraploid of Saccharomyces cerevisiae strain were investigated. Respiratory deficient mutants by spontaneous mutation were absolved more frequently in the haploid than in the diploid, triploid and tetraploid. And cell volume, cell surface, cell concentration, dry cell weight, resistance against ultraviolet irradiation, fermentation power, and DNA contents were significantly increased as the ploidy increased.

• Korean Journal of Microbiology
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• v.10 no.2
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• pp.73-78
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• 1972

As the first step in the production of nucleic acid derivatives by microorganisms, adenineless mutants were derived from Brevibacterium ammoniagenes ATCC6872. A culture of Br. ammoniagenes was exposed to ultraviolet rays for 120 second and treated with diethylsulfate in phosphate buffer for 2 hours to reach the designed death rate. The yield of mutants induced was 0.28% by the ultraviolet irradiation and 0.66% by the diethylsulfate treatment. By the diethylsulfate treatment. By the treatment of penicillin G in a hypertonic minimal medium, the yield of mutants was increased from 0.28% to 0.54% and from 0.66% to 1.5%, respectively. Thus, in was demonstrated that diethylsulfate treatment was much more efficient than UV irradiation to induce adenineless mutants of the bacteria, and total strains of 120 adenineless mutants were obtained.

• BMB Reports
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• v.35 no.5
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• pp.452-458
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• 2002

Exposure to ultraviolet light (UV) induces apoptosis in mammalian cells, The caspase group of proteases is required for the appotosis. This pathway is initiated by a release of cytochrome c from the mitochondria into the cytosol. Several Bcl-2 family proteins can regulate the release of cytochrome c by stabilizing the mitochondrial membrane. Here we show that expression of the endogenous bcl-xL was strongly downregulated in NIH3T3 cells within 2 h after UV-C irradiation, and that of bax was upregulated from 8 h after irradiation. Apoptosis was induced in more than 50% of the NIH3T3 cells 48 h after irradiation. Constitutive overexpression of bcl-xL in NIH3T3 cells protected the UV-induced apoptosis by preventing the loss of mitochondrial membrane potential and the activation of caspase 9. There results suggest that downregulation of Bcl-xL is relevant to UV-induced apoptosis of tibroblasts.

• The Korean Journal of Zoology
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• v.20 no.2
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• pp.109-122
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• 1977

Ultraviolet irradiation of the vegetal hemisphere of the fertilized frog egg prior to first cleavage resulted in alterations in neural morphogenesis. The sensitivity to UV irradiation dropped drastically at the point of 2/3 time lapse between fertilization and the appearance of the first cleavage furrow. Scannining electron micrographs revealed a decrease in size of the cells on the surface of the irradiated embryos. However, ectoderm exchange frafts indicated that the ectoderm of the irradiated embryo retains its capaciiy to form a completely normal neural morphology and epidermal surface. These facts were interpreted in terms of a decrease in the capacity for invagination during gastrulation, and subsequent primary embryonic induction.

• The Korean Journal of Zoology
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• v.24 no.4
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• pp.189-200
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• 1981

Drastic alterations in myogenesis could be induced by ultraviolet irradiation of the myogenic cells derived from 12 day old chick embryo skeletal muscle. The effects of irradiation on various aspects, including cell division, transformation to myotubes, and morphology of myoblasts and myotubes, were examined. Irradiated cells were smaller in size, and only few cells transformed resulting in smaller size of myotubes with a narrow width. Both the inhibiting actions to cell division and to fusion were more striking when irradiated at earlier stages after plating. As well, cell division and fusion were inhibited more effectively with increasing UV dose and excessive amount caused cell death. A lowering cell density was thought to account for the decrease in myogenesis and possible reasons for the decrease in the capacity for fusion were discussed in view of the results presented in this report and of the findings from other laboratories.

• Journal of Plant Biology
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• v.13 no.2
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• pp.15-20
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• 1970

The treatment of X-ray was manipulated with the large focus of X-ray which was produced the capacity of 90 kilovoltage and 30 milliamphere in the distance of 50 centimeter. The germination of each gruop irradiated with X-ray for 5, 6, and 7 seconds was more delayed in the growth of carrot seed than those of the control group. However the germination of each group irradiated with X-ray for 2, 3, and 4 seconds was rather accelerated than those of the control group. The irradiation of ultraviolet light was carried out in the distance of 20 centimeter by Toshiba germidicial lamp which appeared the wavelength of 2537A$^{\circ}$. The germination of each group irradiated with ultraviolet light for 9, 15, 20, and 40 minutes was more delayed than those of the control group, but the germination of carrot seed was accelerated by adequate dosage of ultraviolet light. Consuquently it was suggested for the author that the inhibited substance contained in carrot seed would be certain fatty substance, becasue the germination of carrot seed was more accelerated by the treatment of acetone than those of X-ray and ultraviolet light.