• Textile Coloration and Finishing
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• v.32 no.4
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• pp.185-192
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• 2020

A novel binding site for metal ion made by designing molecule with tetrazolo quinoline with hydrazine carboxamide (TQC) and the designed molecule successfully synthesized. The probe works by selectively detecting Al3+ ion via both fluorimetric and colorimetric approach. The probe's effectiveness towards aluminium ion detection is highly sensitive and selective with no substantial interference with other competing ions. The added Al3+ ion to TQC fetched a rapid change of visual color to yellow from colorless, also the response of fluorescence turn-on. The fluorescence turn-on and color change visibly by the probe TQC with Al3+ ion credited to the ICT phenomenon (intramolecular charge-transfer transition). The likely interaction of the probe with aluminium ion has also been there predicted from ESI-MS spectral analysis results. The usefulness of the probe confirmed by practical utility by making a test kit to monitor Al3+ ion in water which showed a naked eye detection by notable color change.

• Journal of Sensor Science and Technology
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• v.32 no.2
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• pp.82-87
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• 2023

This study proposes a pH-dissolved-oxygen monitoring system using 8-HydroxyPyrene-1,3,6-trisulfonic acid Trisodium Salt (HPTS) and tris(4,7-diphenyl-1,10-phenanthroline)Ruthenium(II) chloride (Ru_dpp). Commercial water-quality sensors are electrochemical devices that require frequent calibration and cleaning, are subject to high maintenance costs, and have difficulties conducting measurements in real-time. The proposed pH-dissolved-oxygen monitoring system selects a thin-film sensing layer to measure the change in fluorescence intensity. This change in fluorescence intensity is based on reactions with hydrogen ions in an aqueous solution at a given pH and specific amount of dissolved oxygen. The change in fluorescence intensity is then measured using light-emitting diodes and photodiodes in response to HPTS and Ru_dpp. This method enables the development of a relatively small, inexpensive, and real-time measureable water-quality measurement system.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1225-1230
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• 2004

The effects of substrate material on the local heating performance of microheaters are studied by both numerical analysis and experiment. Transient conduction analysis shows that the substrate material with low thermal conductivity is critical to the local heating and fast response. A measurement technique for surface temperature field in microscale is newly proposed, which uses temperature sensitive fluorescent dye coated on the surface. The measured surface temperature fields on microheater arrays fabricated on different substrates are presented.

• Animal cells and systems
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• v.10 no.2
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• pp.73-77
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• 2006

Caspase-11 has been known as a dual regulator of apoptosis and inflammatory response. An unusual feature of caspase-11 is that its expression is induced by apoptotic or proinflammatory stimuli. Utilizing these unusual features of caspase-11, we have developed a simple and sensitive assay method to screen pro- or anti-apoptotic/inflammatory molecules. To develop this assay method, we generated a reporter construct where GFP expression is regulated by caspase-11 promoter. When several types of cultured cells were transfected with this reporter construct and subsequently treated with various apoptotic or proinflammatory molecules, expression of GFP by the activation of caspase-11 promoter was easily detected by fluorescence microscopy or spectrofluorometry. In addition, a reduction of the GFP fluorescence was detected when an agent reported to suppress caspase-11 induction was applied. These results suggest that our reporter system can be used to screen pro- or anti-apoptotic/inflammatory molecules.

• Korean Journal of Environmental Biology
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• v.22 no.1
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• pp.233-241
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• 2004

Chlorophyll fluorescence and antioxidative enzyme activity were investigated from leaves of Crinum asiaticum var. japonicum under the natural condition in winter, in order to monitor plant response and physiological states such as vitality, productivity and so on. In the O-J-I-P transients, the fluorescence intensity of J, I, P-step decreased remarkably depending on temperature drop in winter. The photochemical efficiencies of PSII, Fv/Fm, were significantly low in late winter with decrease of Fm. These results indicate that Crinum plants were affected by seasonal drop of temperature. The catalase activity significantly decreased depending on temperature drop in winter. However, the activity of superoxide dismutase ascorbate peroxidase and peroxidase slightly increased in winter while some isoenzymes appeared in winter. These results, with the remarkable decrease of Ev/Fm in winter, represent that Crinum plants were exposed to oxidative stress and subsequently damaged leading to cell death.

• Analytical Science and Technology
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• v.8 no.3
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• pp.221-227
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• 1995

The fiber optic fluorosensor that shows a specific selectivity for calcium ion is studied. This sensor employs protein Calmodulin(CaM) which forms a fluorescent chelate with $Ca^{2+}$. A dialysis membrane is used to entrap a fluorescein isothiocyanate-labeled CaM solution at the common end of a bifurcated fiber optic bundle. The sensing mechanism of this sensor is based on the shifts in the fluorescence spectrum of metal-calmodulin complexes which FCaM forms a chelate with $Ca^{2+}$. Upon binding with $Ca^{2+}$, CaM undergoes a conformational change which induces a change in the fluorescence of FCaM. This change in fluorescence signal which is measured by photomultiflier tube is related to the concentration of $Ca^{2+}$ for calibration curve. Detection limit for $Ca^{2+}$ and the interference effects by $Mg^{2+}$, $Eu^{3+}$ and $La^{3+}$ for this sensor are studied. Response time and life time for this fluorosensor are also investigated.

• Korean Journal of Optics and Photonics
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• v.24 no.2
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• pp.71-76
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• 2013

Using fluorescence correlation spectroscopy, we analyzed the change of effective focal volume of a confocal system with light intensity. The fluorescence correlation spectroscopy system was home-built in accordance with the He-Ne laser with a wavelength of 632.8 nm, and two kinds of samples (AlexaFluor657 and Quantum dot655) suitable for the wavelength of the laser beam were used. For each sample, we analyzed and compared the correlation functions obtained while changing the intensity of the light source in a range of 1~50 ${\mu}W$. The result shows that the radius of the focal area increases linearly through the increase of particle number and diffusion time in response to an intensity change in weak light below 10 ${\mu}W$. In the higher intensity region (>10~15 ${\mu}W$), the increasing rate of particle number and diffusion time keep increasing but at a much slower rate. Through this result, it was also found that the radius increasing rate of the focal area was reduced however, the radius still increased slightly.

• Nano
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• v.13 no.12
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• pp.1850147.1-1850147.14
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• 2018

In this work, water-soluble and blue-emitting carbon nanodots (CDs) were synthesized from apple peels for the first time via one-step hydrothermal method. The synthetic route is facile, green, economical and viable. The as-prepared CDs were characterized thoroughly by transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman, Fourier transform infrared (FT-IR), X-ray photoelectron (XPS), fluorescence and UV-Vis absorption spectroscopy in terms of their morphology, surface functional groups and optical properties. The results show that these CDs possessed ultrasmall size, good dispersivity, and high tolerance to pH, ionic strength and continuous UV irradiation. Significantly, the CDs had fast and reversible response towards temperature, and the accurate linear relationship between fluorescence intensity and temperature was used to design a novel nanothermometer in a broad temperature range from 5 to $65^{\circ}C$ facilely. In addition, the fluorescence intensity of CDs was observed to be quenched immediately by Cr(VI) ions based on the inner filter effect. A low-cost Cr(VI) ions sensor was proposed employing CDs as fluorescent probe, and it displayed a wide linear range from 0.5 to $200{\mu}M$ with a detection limit of $0.73{\mu}M$. The practicability of the developed Cr(VI) sensor for real water sample assay was also validated with satisfactory recoveries.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.63-63
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• 2020

This study investigated the growth of native ferns under indoor light intensities to identify the introduction possibility as in-door ornamental plants. Three evergreen perennial fern species used in this experiment were Coniogramme japonica (Thunb.) Diels, Woodwardia japonica (L. f.) Sm., and Cyclosorus acuminatus (Houtt.) Nakai ex H. Itô. The light intensities were adjusted to 10, 50, 100 and 200 PPFD (µmol·m^-2·s^-1) based on the measurement of the various indoor light quantities. The experiment was conducted for a total of 8 weeks, and the light period (12/12h), temperature (25±1℃), and humidity (55±3%) were maintained during the experiment. The control plant group was grown in glass greenhouse for the same period. As the result of the study, in door C. japonica showed better growth under light intensities of 100, 200 PPFD. However, withering of the plants were observed under all light intensities except the control, which causes an ornamental value decrease. This seems to be related to the increase of DIo/RC value in chlorophyll fluorescence parameters. In the W. japonica growth data, the plant height was not significantly different from the control but, the leaf number decreased more than a two-fold. Also, the formed leaves turned brown and showed a poor growth and SPAD value at 200 PPFD had decreased significantly. Growth data of C. acuminatus was not significantly different with the control at all light intensities however, withering was observed at 100 and 200 PPFD. In chlorophyll fluorescence parameters, significant decrease in Pi_Abs and increase in DIo/RC value at 200 PPFD impose that stress caused by the intense light might be the reason of the withering of the plants.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.612-616
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• 2017

An experimental study investigates the flame response characteristics of non-premixed flame and premixed flame. Air was used as the oxidant. Hydrogen($H_2$)/methane($CH_4$) was used as the fuel, and the mixing ratio of the fuel was 50/50%. Flame response characteristics for various velocity perturbations were experimented. The flame images was acquired using the OH fluorescence measurement and the images were digitized using MatLab code. The results of the premixed flame show that flame perturbation increases as the oscillation amplitude increases. As the amplitude increases, the gain value of the flame transfer function is observed to be a linear behavior. The flame length of a nonpremixed flame decreases as the oscillation amplitude increases. Also, it was confirmed that the gain value according to the amplitude behaves nonlinearly.