• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.120-120
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• 2022

Agrivoltaic System (AVS) was introduced with the concept that it could generate electricity by using the extra light remain after crops use for photosynthesis in farm, which can earn additional income. However, crop yield was declined under the AVS condition due to the decrease in light energy. In the past, many researchers have been studied about crop states under shading conditions. However, the phenomenon of partial shading such as under the AVS is not well studied. In this study, to figure out the response of crop under the different light conditions, the electron transport rate (ETR) and non-photochemical quenching (NPQ) of rice was investigated using the chlorophyll fluorescence measurement. Also, physiological changes of crops under the shading conditions were investigated. The growth experiment under partial shading under AVS and overall shading which made of 35% shade cloth was conducted to understand the eco-physiological responses of rice to light in terms of the photosynthesis. Under the shading conditions, SPAD value and chlorophyll contents were higher, but the leaf thickness was lower than control. The overall shading condition show lower ETR than others during the growing season. In contrast, NPQ was higher than other treatments. This means the available light energy cannot contribute to photosynthesis under the shading condition.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.278-280
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• 2019

Flow cytometer is one of the instrument that can measure various optical properties of a single cell or microparticle. These parameters including size, granularity, and fluorescence intensity are determined by the physical and optical interaction of the cells with excitation light source. However, users have some difficulties such as high cost, size of instrument, and limited fluorescence selectivity. In addition, abundant data is also unintentionally acquired even though user wants to have a single optical parameter. For these reasons, the use of flow cytometer is more challenging for researchers to apply their study. Therefore, the proposed study aims to develop a low-cost portable fluorescence acquisition system using a commercially available light-emitting diode and photodiode. It is designed by a 3D printer, and fluorescence selectivities are increased by changing of the light source / optical filter / detection sensor. Various number sets of fluorescently labeled cells were measured, and its feasibility was evaluated through the proposed system. As a result, acquried fluorescence intensities were proportional to the concentration of the cells and showed high linearity.

• Journal of Ginseng Research
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• v.16 no.2
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• pp.124-128
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• 1992

Vsing the phosphorylated thylakoid membrane induced by 5-35kLux of light intensities, we investigated the chlorophyll nuorescence quenching of PSII and the phosphorylation of LHCPII i in relation to the chlorophyll-bleaching of Panax ginseng C.A. Meyer. In the Presence of DCMU, both of the fluorescence yield of non-phosphorylated thylakoid and the rate of fluorescence quencing dependent on the Phosphorylation were high p. ginseng more then Glyine max L. And at the high light F intensity (above 25 kLux) the fluorescence quenching rate of p. ginseng compared with that of G. max reached nearly to 2 times. The LHCPII of P. ginseng was composed of 3 major Polypeptides (24.5, 26 and 27kD) and 3 minor polypeptides (24, 25.3 and 28.3kD) in the region of 24-29kD and differed, from G. max in both of the number and quantity of polypeptides. Among these polypeptides, the phosphorylated polypeptide dependent on the light intensity was 24kD in P. ginseng.

• The korean journal of orthodontics
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• v.49 no.4
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• pp.246-253
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• 2019

Objective: To evaluate the effectiveness of three different caries-preventing agents on artificial caries in a Streptococcus mutans-based caries model. Methods: Sixty-five caries-free human molar enamel blocks were treated with a demineralization solution and a remineralization solution. The specimens were assigned to the following groups according to the caries-protective product applied: group A, chlorhexidine varnish; group B, fluoride-releasing chemically cured sealant; group C, fluoride-releasing lightcured sealant; group D, positive control (specimens that were subjected to de- and remineralization cycles without treatment with any caries-protective agents); and group E, negative control (specimens that were not subjected to de- and remineralization cycles). Samples in groups A-D were stored in demineralization solution with S. mutans and thereafter in artificial saliva. This procedure was performed for 30 days. Average fluorescence loss (${\Delta}F$) and surface size of the lesions were measured using quantitative light-induced fluorescence at baseline and on the 7th, 14th, and 30th days. Results: After 30 days, group A demonstrated a significant increase in ΔF and the surface size of the lesions, no significant difference in comparison with the positive control group, and a significant difference in comparison with the negative control group. Group B showed no significant changes in both parameters at any of the measurement points. While group C showed increased ${\Delta}F$ after 14 days, no significant fluorescence change was observed after 30 days. Conclusions: Both fluoride-releasing sealants (chemically or light-cured) show anti-cariogenic effects, but the use of chlorhexidine varnish for the purpose of caries protection needs to be reconsidered.

• BMB Reports
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• v.29 no.5
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• pp.398-404
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• 1996

Light-chilling effects were investigated in chilling-sensitive cucumber (Cucumis sativus L. cv. Ilmichungjang) and chilling-resistant pea (Pisum sativum L. cv. Giant) leaf discs in relation to possible damage in D1 protein. In both plants, dark-chilling did not cause any noticeable changes in (Fv)m/Fm and lincomycin did not affect the decrease in (Fv)m/Fm caused by light-chilling. This result suggests that the de novo synthesis of D1 protein did not occur actively during light-chilling. In pea light-chilled for 6 h. the decreased (Fv)m/Fm was partly recovered in the dark, and almost complete recovery was observed in the light. In cucumber light-chilled for 3 h. the reduced (Fv)m/Fm decreased further for the initial 2 h recovery process in the light regardless of the treatment of lincomycin and recovered very slowly. In both plant species, the treatment of lincomycin inhibited the recovery process in the light, but did not significantly inhibit the process in the dark. In cucumber leaves pulse-labeled with $[^{35}S]Met$, the labeled band intensities of isolated pigment-protein complexes were almost the same during the 6 h light-chilling, but significant decreases in band intensities were observed during the 3 h recovery period. This result suggests that the irreversibly damaged D1 protein was degraded during the recovery period. However, no noticeable changes were observed in the pea leaves during the 12 h chilling and 3 h recovery period. The polyacrylamide gel electrophoresis of the pigment-protein complexes showed that the principal lesion sites of light-chilling were different from those of room temperature photoinhibition.

• Proceedings of the Korea Contents Association Conference
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• 2014.06a
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• pp.307-308
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• 2014

• Journal of the Korean Applied Science and Technology
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• v.29 no.1
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• pp.122-128
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• 2012

The influences of fluorescence, scattering, and flocculation in turbid material by light scattering of L-aspartic acid, preservative and emulsifier were interpreted for the scattered fluorescence intensity and wavelength. They have been studied the molecular properties by the spectroscopy of laser induced fluorescence (LIF) and flocculation. The effects of optical properties in scattering media have been found by the optical parameters(${\mu}_s$, ${\mu}_a$, ${\mu}_t$). Flocculation is an important step in many solid-liquid separation processes and is widely used. When two particles approach each other, interactions of several colloid particles can come into play which may have major effect on the flocculation and LIF process. The values of scattering coefficient ${\mu}_s$ are large by means of the increasing scattering of scatterer, The values have been found that the slope decays exponentially as a function of concentration from laser source to detector by our experimental result. It may also aid in designing the best model for oil chemistry, bio-pharmaceutical products, laser medicine and application of medical engineering on LIF and coagulation in particle transport mode.

• Bulletin of the Korean Chemical Society
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• v.34 no.2
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• pp.539-544
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• 2013

$Ag@SiO_2@SiO_2$(FITC) nanocomposites were prepared by the simple polyol process and St$\ddot{o}$ber method. Fluorescence enhancement of fluorescein moiety (fluorescein isothiocyanate, FITC) was investigated in the presence of silver nanoparticles in $Ag@SiO_2@SiO_2$(FITC) system with varying thickness (X nm) of first silica shell. Maximum enhancement factor of 4.3 fold was achieved in $Ag@SiO_2@SiO_2$(FITC) structure with the first silica shell thickness of 8 nm and the average separation distance of 11 nm between the surface of silver nanoparticle and fluorescein moiety. The enhancement is believed to be originated from increased excitation rate of fluorescein moiety due to concentrated local electromagnetic field which was improved by interaction of light with silver nanoparticles.

• Molecules and Cells
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• v.45 no.1
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• pp.41-50
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• 2022

The recently developed correlative super-resolution fluorescence microscopy (SRM) and electron microscopy (EM) is a hybrid technique that simultaneously obtains the spatial locations of specific molecules with SRM and the context of the cellular ultrastructure by EM. Although the combination of SRM and EM remains challenging owing to the incompatibility of samples prepared for these techniques, the increasing research attention on these methods has led to drastic improvements in their performances and resulted in wide applications. Here, we review the development of correlative SRM and EM (sCLEM) with a focus on the correlation of EM with different SRM techniques. We discuss the limitations of the integration of these two microscopy techniques and how these challenges can be addressed to improve the quality of correlative images. Finally, we address possible future improvements and advances in the continued development and wide application of sCLEM approaches.

• Journal of the Korean Society of Visualization
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• v.21 no.3
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• pp.65-74
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• 2023

Compared to epifluorescence(EPI) microscopy which captures fluorescence from the entire depth of sample, total internal reflection fluorescence(TIRF) can selectively visualize only a single surface of it. TIRF uses a thin evanescent field generated by the total internal reflection of laser light on surface. However, conventional TIRF system are designed for total internal reflection to occur at the upper surface of sample, making them unsuitable for sessile droplet imaging. We designed a TIRF system suitable for a sessile droplet imaging by utilizing slide glass as a lightguide. We presented the details for constructing the TIRF system using a prism, slide glass, air slit, and optical trap. Then, we compared the TIRF with EPI by imaging the droplet with fluorescent particles during its drying process. As a result, TIRF allows us to distinctly visualize the drying pattern on the bottom surface of droplet.