• Proceedings of the IEEK Conference
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• 2003.07d
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• pp.1545-1548
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• 2003

This paper presents a method for detecting skin tumors on chicken carcasses using hyperspectral images. It utilizes both fluorescence and reflectance image information in hyperspectral images. A detection system that is built on this concept can increase detection rate and reduce processing time. Chicken carcasses are examined first using band ratio FCM information of fluorescence image and it results in candidate regions for skin tumor. Next classifier selects the real tumor spots using PCA components information of reflectance image from the candidate regions.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.187-190
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• 2002

Confocal microscopy is very popular technology in bio-medical inspection due to its ability to reject background signals and to measure very thin slide of thick specimens, which is called optical sectioning. But intensity of detected signal in fluorescence type confocal microscopy is so small that only 0.2% of emitted fluorescence light can be detected in the best case. In this paper, we proposed the reflecting optical system to improve the detection intensity and designed the optical system by optimal design method. At the end of the paper, we analyzed the characteristics of the proposed reflecting optical system.

• Mass Spectrometry Letters
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• v.6 no.2
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• pp.43-47
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• 2015

Detection of mefenamic acid (M, non-steroidal anti-inflammatory drug, NSAIDs) and its metallodrug was investigated using electrospray ionization mass spectrometry (ESI-MS) and fluorescence spectroscopy. ESI-MS data (500 µL, 1×10-3 M) revealed high detection sensitivity for the drug and metallodrug. ESI-MS spectra revealed peaks at 242, 580, and 777 Da corresponding to [M+H]+, [63Cu(M-H)2(H2O)2+H]+, and [56Fe(M-H)3+H]+, respectively. The metal:mefenamic ratios of ESIMS spectra are in complete agreement with the fluorescence spectroscopy results (1:2 for Cu(II) and 1:3 for Fe(III)). ESI is a soft ionization technique that can be used on labile metallo-mefenamic acids and is promising for the detection of these species in environmental samples and biological fluids.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2415-2418
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• 2008

Polydiacetylenes (PDAs) are very attractive chemical substances which have distinctive features of color change and fluorescence emission by thermal or chemical stress. Especially, when PDAs contact with solutions of a particular pH, such as a strong alkaline sodium hydroxide (NaOH) solution or a strong acidic hydrogen chloride (HCl) solution, PDAs change their color from non-fluorescent blue to fluorescent red. In this study, we propose a novel method to detect alkaline pH using PDAs and NaOH solutions by hydrodynamic focusing on a microfluidic chip. Preliminary results indicate that the fluorescent intensity of PDAs increases in respond to the NaOH solution concentrations. Also, the fluorescence is quenched back when the PDAs are in contact with a HCl solution. These results are useful in a microfluidic PDA sensor chip design for pH detection.

• Journal of the Korean Vacuum Society
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• v.9 no.1
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• pp.76-80
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• 2000

CF & $CF_2$ radicals in a $C_4F_8$ inductively coupled plasma were observed with laser induced fluorescence. 251.9nm UV laser was used for the $CF_2$ excitation and 265.3nm UV emitted light for the detection which has the maximum intensity among many induced fluorescence lights. In the case of CF radical detection, 232.9nm UV laser was used for the excitation and 247.6nm for the detection. $CF_2$ radical density increased toward substrate, while CF radical had its maximum at about 10nm away from the substrate. The atomic fluorine density which was studied by the actinometry increased as the position moves away from the substrate. This phenomena was thought to have a close relation with the polymer growth on the wafer. When the bias voltage increased, $CF_2$ , CF radicals decreased while the atomic fluorine increased tio some extent and then decreased, which was thought to be due to the change in the ionization and dissociation.

• Journal of Powder Materials
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• v.29 no.6
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• pp.453-458
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• 2022

We successfully synthesize water-dispersible CTAB-capped CdSe@ZnS quantum dots with the crystal size of the CdSe quantum dots controlled from green to orange colors. The quenching effect of Fe(DTC)₃ is very efficient to turn off the emission light of quantum dots at four molar ratios of the CdSe quantum dots, that is, the effective covering the surface of quantum dots with Fe(DTC)₃. However, the reaction with Fe(DTC)₃ for more than 24 h is required to completely realize the quenching effect. The highly quenched quantum dots efficiently detect nitric oxide at nano-molar concentration of 110nM of NO with 34% of recovery of emission light intensity. We suggest that Fe(DTC)₃-hybridized CdSe@ZnS quantum dots are an excellent fluorescence resonance energy transfer probe for the detection of nitric oxide in biological systems.

• Journal of information and communication convergence engineering
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• v.17 no.1
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• pp.49-59
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• 2019

Biosensors, which are analysis devices used to convert biological reactions into electric signals, are made up of a receptor component and a signal transduction part. Graphene quantum dots (GQDs) and carbon quantum dots (CQDs) are new types of carbon nanoparticles that have drawn a significant amount of attention in nanoparticle research. The unique features exhibited by GQDs and CQDs are their excellent fluorescence, biocompatibility, and low cytotoxicity. As a result of these features, carbon nanomaterials have been extensively studied in bioengineering, including biosensing and bioimaging. It is extremely important to find biomaterials that participate in biological processes. Biomaterials have been studied in the development of fluorescence-based detection methods. This review provides an overview of recent advances and new trends in the area of biosensors based on GQDs and CQDs as biosensor platforms for the detection of biomaterials using fluorescence. The sensing methods are classified based on the types of biomaterials, including nucleic acids, vitamins, amino acids, and glucose.

• Toxicological Research
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• v.34 no.1
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• pp.1-6
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• 2018

The purpose of this study was to detect cell death in the liver of mice treated with thioacetamide (TAA) using fluorescence bioimaging and compare this outcome with that using conventional histopathological examination. At 6 weeks of age, 24 mice were randomly divided into three groups: group 1 (G1), control group; group 2 (G2), fluorescence probe control group; group 3 (G3), TAA-treated group. G3 mice were treated with TAA. Twenty-two hours after TAA treatment, G2 and G3 mice were treated with Annexin-Vivo 750. Fluorescence in vivo bioimaging was performed by fluorescence molecular tomography at two hours after Annexin-Vivo 750 treatment, and fluorescence ex vivo bioimaging of the liver was performed. Liver damage was validated by histopathological examination. In vivo bioimaging showed that the fluorescence intensity was increased in the right upper part of G3 mice compared with that in G2 mice, whereas G1 mice showed no signal. Additionally ex vivo bioimaging showed that the fluorescence intensity was significantly increased in the livers of G3 mice compared with those in G1 or G2 mice (p < 0.05). Histopathological examination of the liver showed no cell death in G1 and G2 mice. However, in G3 mice, there was destruction of hepatocytes and increased cell death. Terminal deoxynucleotidyl transferase dUTP nick end labeling staining confirmed many cell death features in the liver of G3 mice, whereas no pathological findings were observed in the liver of G1 and G2 mice. Taken together, fluorescence bioimaging in this study showed the detection of cell death and made it possible to quantify the level of cell death in male mice. The outcome was correlated with conventional biomedical examination. As it was difficult to differentiate histological location by fluorescent bioimaging, it is necessary to develop specific fluorescent dyes for monitoring hepatic disease progression and to exploit new bioimaging techniques without dye-labeling.

• Korean Journal of Agricultural Science
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• v.49 no.3
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• pp.495-510
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• 2022

In this study, fluorescence hyperspectral imaging (FHSI) was used for the rapid, non-destructive detection of fake, manmade eggs from real eggs. To identify fake eggs, protoporphyrin IX (PpIX)-a natural pigment present in real eggshells-was utilized as the main indicator due to its strong fluorescence emission effect. The fluorescence images of real and fake eggs were acquired using a line-scan-based FHSI system, and their fluorescence features were analyzed based on spectroscopic techniques. To improve the detection performance and accuracy, an optimal waveband combination was investigated with analysis of variance (ANOVA), and its fluorescence ratio images (588/645 nm) were created for visualization of the real eggs between two different egg groups. In addition, real and fake eggs were scanned using a one-waveband (645 nm) handheld fluorescence imager that can perform real-time scanning for on-site applications. Then, the results of the two methods were compared with one another. The outcome clearly shows that the newly developed FHSI system and the fluorescence handheld imager were both able to distinguish real eggs from fake eggs. Consequently, FHSI showed a better performance (clearer images) compared to the fluorescence handheld imager, and the outcome provided valuable information about the feasibility of using FHSI imaging with ANOVA for the discrimination of real and fake eggs.

• The Plant Pathology Journal
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• v.32 no.4
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• pp.300-310
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• 2016

Pathogen infection in plants induces complex responses ranging from gene expression to metabolic processes in infected plants. In spite of many studies on biotic stress-related changes in host plants, little is known about the metabolic and phenotypic responses of the host plants to Pseudomonas cichorii infection based on image-based analysis. To investigate alterations in tomato plants according to disease severity, we inoculated plants with different cell densities of P. cichorii using dipping and syringe infiltration methods. High-dose inocula (${\geq}10^6cfu/ml$) induced evident necrotic lesions within one day that corresponded to bacterial growth in the infected tissues. Among the chlorophyll fluorescence parameters analyzed, changes in quantum yield of PSII (${\Phi}PSII$) and non-photochemical quenching (NPQ) preceded the appearance of visible symptoms, but maximum quantum efficiency of PSII ($F_v/F_m$) was altered well after symptom development. Visible/near infrared and chlorophyll fluorescence hyperspectral images detected changes before symptom appearance at low-density inoculation. The results of this study indicate that the P. cichorii infection severity can be detected by chlorophyll fluorescence assay and hyperspectral images prior to the onset of visible symptoms, indicating the feasibility of early detection of diseases. However, to detect disease development by hyperspectral imaging, more detailed protocols and analyses are necessary. Taken together, change in chlorophyll fluorescence is a good parameter for early detection of P. cichorii infection in tomato plants. In addition, image-based visualization of infection severity before visual damage appearance will contribute to effective management of plant diseases.