• Proceedings of the Korean Society of Potoscience Conference
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• spring
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• pp.11-11
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• 2000

• Journal of Photoscience
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• v.9 no.2
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• pp.500-502
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• 2002

In vitro and in vivo studies have reported the induction of matrix metaloproteinase (MMP)-1 in the fibroblasts by ultraviolet (UV) A irradiation. We constructed the skin equivalent model using HaCaT cells as keratinocytes and human neonatal dennal fibroblasts as fibroblasts in the present study. The induction of MMP-l in the fibroblasts was confirmed immunohistochemically 6 hours after UVA irradiation using this model. This model was simply composed of human keratinocytes and fibroblasts. To our knowledge, there have been a few papers concerning the skin equivalent model in the field of photobiology. The effect of UVA exposure to fibroblasts through keratinocytes was examined using this model. The cross-talk can be examined between keratinocytes and fibroblasts. This model can be a useful tool in the field of photobiology.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.14
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• pp.6039-6046
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• 2015

Aims: To investigate effect of metallic nanoparticles, silver (AgNPs) and gold nanoparticles (AuNPs) as antitumor treatment in vitro against human breast cancer cells (MCF-7) and their associated mechanisms. This could provide new class of engineered nanoparticles with desired physicochemical properties and may present newer approaches for therapeutic modalities to breast cancer in women. Materials and Methods: A human breast cancer cell line (MCF-7) was used as a model of cells. Metallic nanoparticles were characterized using UV-visible spectra and transmission electron microscopy (TEM). Cytotoxic effects of metallic nanoparticles on MCF-7 cells were followed by colorimetric SRB cell viability assays, microscopy, and cellular uptake. Nature of cell death was further investigated by DNA analysis and flow cytometry. Results: Treatment of MCF-7 with different concentrations of 5-10nm diameter of AgNPs inhibited cell viability in a dose-dependent manner, with IC50 value of $6.28{\mu}M$, whereas treatment of MCF-7 with different concentrations of 13-15nm diameter of AuNPs inhibited cell viability in a dose-dependent manner, with IC50 value of $14.48{\mu}M$. Treatment of cells with a IC50 concentration of AgNPs generated progressive accumulation of cells in the S phase of the cell cycle and prevented entry into the M phase. The treatment of cells with IC50 concentrations of AuNPs similarly generated progressive accumulation of cells in sub-G1 and S phase, and inhibited the entrance of cells into the M phase of the cell cycle. DNA fragmentation, as demonstrated by electrophoresis, indicated induction of apoptosis. Conclusions: Our engineered silver nanoparticles effectively inhibit the proliferation of human breast carcinoma cell line MCF-7 in vitro at high concentration ($1000{\mu}M$) through apoptotic mechanisms, and may be a beneficial agent against human carcinoma but further detailed study is still needed.

• Applied Biological Chemistry
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• v.20 no.1
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• pp.10-25
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• 1977

The photobiological receptors of phototactic, phototropic, and photomorphogenic responses of various organisms have been described in terms of spectroscopic, photophysical and photochemical properties which may be relevant in elucidating the energy transduct ion mechanism(s) in photobiology. The photoreceptors discussed include carotenoids, flavins, stentorin and phytochrome. Although the molecular modes of their photobiological action still remain largely unexplained, it is possible to suggest several primary molecul ar processes of the photoreceptors in eliciting responses of various organisms to light.

• Journal of Photoscience
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• v.2 no.2
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• pp.103-106
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• 1995

For studying chlorophyll biosynthetic heterogeneity of plants, it is necessary to establish a technique for microassay of a putative monovinyl and divinyl protoporphyrin IX. Precise determination of the amounts of monovinyl and divinyl protoporphyrin IX is difficult with optical electronic spectroscopy even at 77$\circ$C. Such a problem could be solved by conversion of protoporphyrin IX to protoporphyrin IX dimethylester with diazomethane and subsequent Mg insertion into protoporphyrin IX dimethylester by reaction with a Grignard solution. The proportion of monovinyl and divinyl Mg-protoporphyrin IX dimethylester formed was measured instead of direct measuring that of protoporphyrin IX by low-temperature spectrofluorometry. The relative proportions of monovinyl and divinyl of protoporphyrin IX, Mg-protoporphyrin IX, and Mgprotoporphyrin IX dimethylester have not changed during the chemical conversion steps. This analysis system could be useful for the study of the monovinyl and divinyl chlorophyll biosynthetic routes in plants.

• BMB Reports
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• v.29 no.4
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• pp.327-334
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• 1996

In this study, the origin of the monovinyl chlorophyll a carboxylic biosynthetic route was investigated in barley (Hordeum vulgare L.) and com (Zea mays L.). Protoporphyrin IX accumulated in vivo or in vitro was found to be all of the divinyl form. Furthermore, the conversion of divinyl protoporphyrin IX to monovinyl protoporphyrin IX in vitro was not observed. In contrast, the biosynthesis and accumulation of monovinyl Mg-protoporphyrin IX and its methyl ester occurred in etiolated leaves and divinyl Mg-protoporphyrin IX was convertible to monovinyl Mg-protoporphyrin IX in vitro. These results suggest that the monovinyl chlorophyll ${\alpha}$ carboxylic biosynthetic route in plants may originate from the divinyl Mg-protoporphyrin IX pool.

• Journal of the Korean Applied Science and Technology
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• v.28 no.1
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• pp.102-108
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• 2011

The study of wave propagation and scattering in biological media has become increasingly important in recent years. The propagation of light within tissues is an important problem that confronts the dosimetry of therapeutic laser delivery and the development of diagnostic spectroscopy. In the clinical application of photodynamic therapy(PDT) and in photobiology, the photon deposition within a tissue determines the spatial distribution of photochemical reactions. Scattered light is measured as a function of the distance (r) between the axis of the incident beam and the detection spot. Consequently, knowledge of the photosensitizer(Chlorophyll-a) function that characterizes a phantom is measured. To obtain the results of scattering coefficients(${\mu}s$) of a turbid material from diffusion described by experimental approach. It was measured the energy fluency of photon radiation at the position of penetration depth. From fluorescence experimental method obtained the analytical expression for the scattered light as the values of $(I/I_o)_{wavelength}$ vs the distance between the center of the incident beam and optical fiber in terms of the condition of "in situ spectroscopy(optically thick)" and real time by fluorometric measurements. The result was compromised with transport of intensities though a random distribution of scatters.

• Journal of the Korean Applied Science and Technology
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• v.22 no.2
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• pp.182-190
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• 2005

The propagation of light radiation within tissues is an important problem that confronts the dosimetry of therapeutic laser delivery and the development of diagnostic spectroscopy. In the clinical application of photodynamic therapy(PDT) and in photobiology, the photon deposition within a tissue determines the spatial distribution of photochemical reactions. Scattered light is measured as a function of the distance (r) between the axis of the incident beam and the detection spot. Consequently, knowledge of the photosensitizer(Chlorophyll-a) function that characterizes a phantom is important. To obtain the results of scattering coefficients(${\mu}s$) of a turbid material from diffusion described by experimental approach. It was measured the energy fluency of photon radiation at the position of penetration depth. From fluorescence experimental method obtained the analytical expression for the scattered light as the values of $(I\;/I_o)_{wavelength}$ vs the distance between the center of the incident beam and optical fiber in terms of the condition of "in situ spectroscopy(optically thick)" and real time by fluorometric measurements.

• Fisheries and Aquatic Sciences
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• v.3 no.3_4
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• pp.222-227
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• 2000

Fabrea salina living at salt pond is an interesting ciliate in the research of photobiology and live food for aquaculture. This study was carried out to understand the natural habitat of F. salina at salt pond, which would be a basic biological knowledge for the indoor mass culture of this ciliate. In this research, the water quality as temperature, salinity, dissolved oxygen, and chlorophyll-a was examined with the population density of the ciliate at salt pond. The highest population density of F. salina occurred at 109 ppt and $31^{\circ}C$with 2,390 inds./L in August, and the distribution of the ciliate was positively correlated with salinity, temperature, and chlorophyll­a. Even though F. salina is a very euryharine ciliate, it did not occur at the salinity below 47 ppt in this study. Its reason is able to be explained with the occurrence of many predators as small fish and food competitors as zooplankton living at low salinity of salt pont. While F. salina occurred with Anemia at the same habitat using the same food source, the optimum salinity for the ciliate was a little higher than that of Anemia, and the optimum temperature for the former was a little lower than that of the later. This should be a reason for that these two species have different ecological nich at the same habitat using the same food source.

• ALGAE
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• v.28 no.2
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• pp.193-202
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• 2013

Nitrogen availability and cell density each affects growth and cellular astaxanthin content of Haematococcus pluvialis, but possible combined effects of these two factors on the content and productivity of astaxanthin, especially under outdoor culture conditions, is less understood. In this study, the effects of the initial biomass densities IBDs of 0.1, 0.5, 0.8, 1.5, 2.7, 3.5, and 5.0 g $L^{-1}$ DW and initial nitrogen concentrations of 0, 4.4, 8.8, and 17.6 mM nitrate on growth and cellular astaxanthin content of H. pluvialis Flotow K-0084 were investigated in outdoor glass column photobioreactors in a batch culture mode. A low IBD of 0.1 g $L^{-1}$ DW led to photo-bleaching of the culture within 1-2 days. When the IBD was 0.5 g $L^{-1}$ and above, the rate at which the increase in biomass density and the astaxanthin content on a per cell basis was higher at lower IBD. When the IBD was optimal (i.e., 0.8 g $L^{-1}$), the maximum astaxanthin content of 3.8% of DW was obtained in the absence of nitrogen, whereas the maximum astaxanthin productivity of 16.0 mg $L^{-1}\;d^{-1}$ was obtained in the same IBD culture containing 4.4 mM nitrogen. The strategies for achieving maximum Haematococcus biomass productivity and for maximum cellular astaxanthin content are discussed.