• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3405-3409
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• 2013

The activation of heat shock factor 1 (HSF1) can be induced by the changes in environmental pH, but the mechanism of HSF1 activation by acidification is not completely understood. This paper reports that a low pH (pH~6.0) can trigger human HSF1 activation. Considering the involvement of the imidazole group of histidine residues under acid pH stress, an in vitro EMSA experiment, Trp-fluorescence spectroscopy, and protein structural analysis showed that the residue, His83, is the essential for pH-dependent human HSF1-activation. To determine the roles of His83 in the HSF1-mediated stress response affecting the cellular acid resistance, mouse embryo fibroblasts with normal wild-type or mutant mouse HSF1 expression were preconditioned by heating or pH stress. The results suggest that His83 is essential for HSF1 activation or the HSF1-mediated transcription of heat shock proteins, in protecting cells from acid pH stress.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.489-493
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• 2014

A phenylbenzimidazole derivatized sensor (L) that behaves as a ratiometric fluorescent receptor for $Zn^{2+}$ in water has been described. In HEPES buffer at pH 7.4, sensor L displays a weak fluorescence emission band at 367 nm. Upon addition of $Zn^{2+}$, the emission intensity at 367 nm is decreased, concomitantly, a new emission band centered at 426 nm is developed, thus facilitates a ratiometric $Zn^{2+}$ sensing behavior. Sensor L binds $Zn^{2+}$ through a 1:1 binding stoichiometry with high selectivity over other metal cations. Sensor L displays a linear response to $Zn^{2+}$ concentration from 0 to $6.0{\times}10^{-5}M$, sensor L also exhibits high sensitivity to $Zn^{2+}$ with a detection limit of $3.31{\times}10^{-7}M$.

• Bulletin of the Korean Chemical Society
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• v.34 no.2
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• pp.389-393
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• 2013

A rhodamine B-based fluorescent probe for nitrite ion ($NO{_2}^-$) has been designed, synthesized, characterized and its properties for recognition of $NO{_2}^-$ were studied. Nearly non fluorescent probe upon reaction with nitrite ion significantly triggered the fluorescence. Fluorescence response is based on ring opening of the spirolactam of rhodamine B phenyl hydrazide showing maximum absorbance at 552 nm and maximum emission at 584 nm. Probe 3 exhibited high sensitivity and extreme selectivity for nitrite ion over other common ions and oxidants ($Cl^-$, $ClO^-$, $ClO{_2}^-$, $ClO{_3}^-$, $ClO{_4}^-$, $SO{_4}^{2-}$, $SiO{_3}^{2-}$, $NO{_3}^{2-}$, $CO{_3}^{2-}$) examined in methanol water (1:1, v/v) at pH 7.0. The probe might be a new efficient tool for detection of nitrite ion in natural water and biological system.

• 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.

• Mycobiology
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• v.51 no.5
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• pp.273-280
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• 2023

The nucleolus is the largest, membrane-less organelle within the nucleus of eukaryotic cell that plays a critical role in rRNA transcription and assembly of ribosomes. Recently, the nucleolus has been shown to be implicated in an array of processes including the formation of signal recognition particles and response to cellular stress. Such diverse functions of nucleolus are mediated by nucleolar proteins. In this study, we characterized a gene coding a putative protein containing a nucleolar localization sequence (NoLS) in the rice blast fungus, Magnaporthe oryzae. Phylogenetic and domain analysis suggested that the protein is orthologous to Rrp8 in Saccharomyces cerevisiae. MoRRP8-GFP (translational fusion of MoRRP8 with green fluorescence protein) co-localizes with a nucleolar marker protein, MoNOP1 fused to red fluorescence protein (RFP), indicating that MoRRP8 is a nucleolar protein. Deletion of the MoRRP8 gene caused a reduction in vegetative growth and impinged largely on asexual sporulation. Although the asexual spores of DMorrp8 were morphologically indistinguishable from those of wild-type, they showed delay in germination and reduction in appressorium formation. Our pathogenicity assay revealed that the MoRRP8 is required for full virulence and growth within host plants. Taken together, these results suggest that nucleolar processes mediated by MoRRP8 is pivotal for fungal development and pathogenesis.

• Journal of Biomedical Engineering Research
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• v.44 no.3
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• pp.176-181
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• 2023

During cancer treatment, the patient's response to drugs appears differently at the cellular level. In this paper, an image-based cell phenotypic feature quantification and key feature selection method are presented to predict the response of patient-derived cancer cells to a specific drug. In order to analyze the viability characteristics of cancer cells, high-definition microscope images in which cell nuclei are fluorescently stained are used, and individual-level cell analysis is performed. To this end, first, image stitching is performed for analysis of the same environment in units of the well plates, and uneven brightness due to the effects of illumination is adjusted based on the histogram. In order to automatically segment only the cell nucleus region, which is the region of interest, from the improved image, a superpixel-based segmentation technique is applied using the fluorescence expression level and morphological information. After extracting 242 types of features from the image through the segmented cell region information, only the features related to cell viability are selected through the ReliefF algorithm. The proposed method can be applied to cell image-based phenotypic screening to determine a patient's response to a drug.

• Korean Chemical Engineering Research
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• v.49 no.4
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• pp.400-404
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• 2011

Many studies on polydiacetylene(PDA) have been investigated to apply to chemical and biological sensors due to their unique optical properties of color change from blue to red and fluorescence change from non-fluorescence to red fluorescence. Especially, high sensitivity against specific molecules is very important to apply polydiacetylenes to various sensors. In this study, we examined the effect of sensitivity enhancement of 10,12-pentacosadynoic acid(PCDA) vesicles in detection ${\alpha}$-cyclodextrin(CD) according to control of vesicle size by filters with different pore sizes and polymerization temperature. Colorimetric response(CR) was calculated using visible spectrometer. In order to investigate the effect of vesicle size on sensitivity of PDA vesicles, two PCDA vesicles were filtered without filtration and with 0.22 ${\mu}m$ filter. The two PCDA vesicles were polymerized at $25^{\circ}C$ and were incubated with ${\alpha}$-CD(5 mM) for 30 min. The CRs of the former and latter vesicles were 31.4% and 74.0%, respectively. Then, two PCDA vesicles filtered with 0.22 ${\mu}m$ filter were polymerized at $25^{\circ}C$ and $5^{\circ}C$ and were reacted with ${\alpha}$-CD(5 mM) for 30 min to examine the effect of polymerization temperature. The CRs of the former and latter vesicles were 74.0 and 99.2%, respectively. This suggests that vesicle sizes and polymerization temperature are key factors in enhancing the sensitivity of PDA vesicles. In addition, these results are expected to be useful to apply the PDA vesicles as biosensors to detect DNA, protein, and cells.

• Analytical Science and Technology
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• v.10 no.4
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• pp.274-281
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• 1997

Methods to determine terbium(III) ion in aqueous solution by measuring the enhanced fluorescence intensity of terbium(III)-terephthalic acid(TPA) complex ion have been studied. The optimum analytical conditions for pH, excitation wavelength and concentration of TPA were found to be 6.0, 260nm and $4.0{\times}10^{-4}M$, respectively. The fluorescence intensity of the terbium(III) complex ion was further increased with addition of trioctylphosphine oxide (TOPO). In this case Triton X-100 was used to dissolve TOPO in aqueous solution. When TOPO was used, the optimum analytical conditions for pH, excitation wavelength, and concentrations of TPA, TOPO and Triton X-100 were found to be 4.5, 285nm. $4.0{\times}10^{-4}M$, $5.0{\times}10^{-5}M$, and 0.05%, respectively. Under the optimum experimental conditions, calibration curve for Tb(III) was linear over the range from $4.0{\times}10^{-8}M$ to $4.0{\times}10^{-5}M$ and the detection limit was $4.0{\times}10^{-8}M$. When TOPO was used, the concentration range of linear response, and the detection limit were $4.0{\times}10^{-9}M$ to $2.0{\times}10^{-6}M$, and $4.0{\times}10^{-9}M$, respectively. Effects of interferences from various cations for the determination of terbium(III) ion were also investigated.

• Analytical Science and Technology
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• v.11 no.5
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• pp.409-412
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• 1998

The analytical method to determine europium(III) ion in aqueous solution by fluorescence spectroscopy based upon the conformational change of calmodulin in the presence of the analyte has been studied. The fiber optic chemical sensor used in this study was constructed by entrapping a fluorescein-labeled calmodulin solution, EGTA, buffer solution at the common end of a bifurcated fiber optic bundle by means of a dialysis membrane. The calibration curve to determine europium(III) ion was obtained when concentration of calmodulin, concentration of EGTA, Tris-HCl buffer solution, pH, excitation wavelength and fluorescence wavelength were $5.0{\times}10^{-5}M$, 0.50 mM, 5.0 mM, 7.0, 495 nm and 520 nm, respectively. The detection limit was $1.0{\times}10^{-11}M$ and the working range of the calibration curve for the sensor was $1.0{\times}10^{-11}M{\sim}1.0{\times}10^{-9}M$. The response time was 15 minutes. For the determination of europium(III) ion by the present method, $Na^+$ and $K^+$ ions did not interfere but $Ca^{2+}$ ion seriously interfered.

• Progress in Medical Physics
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• v.12 no.1
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• pp.9-17
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• 2001

The prior purpose of this study is to introduce a optical biopsy and evaluate whether the optical biopsy, real-time, non-invasive technique, is a reliable tool to assess response to radiotherapy Four healthy volunteers, and four patients with inflammatory conditions of the oral cavity participated on the study. was obtained from each person enrolled in the study. Using FastEEM(Ercited Emission Matrix) as a optical biopsy tool, normal and tumor spectra are taken from the normal and the tumor regions. And then second optical biopsy are taken from the tumor regions in 4 patients with time delay at 7days.. Using a diagnostic algorithm, made by Gillenwater based on spectra excited at 337nm The Optical Biopsy turned out to be more suited for tumor diagnostic resulting in significant difference fluorescence spectra. The fluorescence intensity of cancerous tissue showed a higher position. The second fluorescence intensity of optical biopsy of cancerous oral tissue has more smaller than the first result. I conclude that optical biopsy, which technique don't need to remove tissue sample from body, and is a real time , and non-invasive measurement is a reliable tool to access to radiotherapy because FastEEM can do measure the variation of the tissue composition chemical, biological, and morphological after radiotherapy. Based on the fluorescence spectrum are taken from the optical biopsy in normal and tumor spectra as well as tumor spectra after 7days.