• Bulletin of the Korean Chemical Society
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• 제35권5호
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• pp.1269-1274
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• 2014

Monoamine oxidases catalyze the oxidative deamination of dietary amines and amine neurotransmitters, and assist in maintaining the homeostasis of the amine neurotransmitters in the brain. Dysfunctions of these enzymes can cause neurological and behavioral disorders including Parkinson's and Alzheimer's diseases. To understand their physiological roles, efficient assay methods for monoamine oxidases are essential. Reviewed in this Perspective are the recent progress in the development of fluorescent probes for monoamine oxidases and their applications to enzyme assays in cells and tissues. It is evident that still there is strong need for a fluorescent probe with desirable substrate selectivity and photophysical properties to challenge the much unsolved issues associated with the enzymes and the diseases.

• 통합자연과학논문집
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• 제1권1호
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• pp.1-4
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• 2008

We developed quantification method based on the concept of candela in physics. The measurement of fluorescence signal from a nude mouse in the research of molecular biology. In the measurement of the optical signal with CCD, the quantification method for photon counts based on bio-luminescence imaging technique can provide comparative reference data. In this paper, we described theoretical derivation of our proposed concept. We hope this method could be a useful standard reference for quantitative date analysis in optical imaging.

• 한국가시화정보학회지
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• 제19권1호
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• pp.43-49
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• 2021

In this experimental study, measurement techniques such as backlight imaging, optical patternator, and laser sheet drop sizing were applied to characterize open-type swirl injector used in Russian liquid rocket engine, RD 107. The typical development of swirl spray was observed in backlight images. The breakup length was measured by using the ratio between Mie scattering and fluorescence signal. Relative Sauter Mean Diameter was measured by using laser sheet drop sizing and the possible source of errors were discussed.

• Current Optics and Photonics
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• 제2권6호
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• pp.595-605
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• 2018

The two-photon process of microscopy provides good spatial resolution and optical sectioning ability when observing quasi-static endogenous fluorescent tissue within an in vivo animal model skin. In order to extend the use of such systems, we developed a two-photon laser scanning microscopy system capable of also capturing $512{\times}512$ pixel images at 90 frames per second. This was made possible by incorporating a 72 facet polygon mirror which was mounted on a 55 kRPM motor to enhance the fast-scan axis speed in the horizontal direction. Using the enhanced temporal resolution of our high-speed two-photon laser scanning microscope, we show that rapid processes, such as fluorescently labeled erythrocytes moving in mouse blood flow at up to 1.2 mm/s, can be achieved.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2003년도 추계학술대회 논문집
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• pp.81-82
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• 2003

We have developed the method for the conjugation of biotinylated DNA to streptavidin-coated QDs. QD-DNA conjugates and a high-sensitive fluorescence imaging technique are adopted to visualize gene transport across the membrane of the live cell in real time. Endocytotic cellular uptake of oligonucleotide and electrically-mediated plasmid DNA transfer into the live cell are monitored by a quantitative microscopic imaging system. Long-term kinetic study enables us to reveal the unknown mechanisms and rate-limiting steps of extracellular and intracellular transport of biomolecules. We designed experimental protocols to conjugate the oligonucleotide or the plasmid DNA to commercially available streptavidin-coated QDs. Gel electrophoresis is used to verify the effect of incubation time and the molar ratio of QDs and DNA on the conjugation efficiency. It is possible to fractionate the QD-DNA conjugates according to the DNA concentration and obtain the purified conjugates by a gel extraction technique.

• International Journal of Oral Biology
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• 제38권1호
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• pp.5-12
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• 2013

Recent studies indicate that reactive oxygen species (ROS) can act as modulators of neuronal activity, and are critically involved in persistent pain primarily through spinal mechanisms. In this study, we investigated the effects of NaOCl, a ROS donor, on neuronal excitability and the intracellular calcium concentration ($[Ca^{2+}]_i$) in spinal substantia gelatinosa (SG) neurons. In current clamp conditions, the application of NaOCl caused a membrane depolarization, which was inhibited by pretreatment with phenyl-N-tert-buthylnitrone (PBN), a ROS scavenger. The NaOCl-induced depolarization was not blocked however by pretreatment with dithiothreitol, a sulfhydryl-reducing agent. Confocal scanning laser microscopy was used to confirm whether NaOCl increases the intracellular ROS level. ROS-induced fluorescence intensity was found to be increased during perfusion of NaOCl after the loading of 2',7'-dichlorofluorescin diacetate ($H_2DCF$-DA). NaOCl-induced depolarization was not blocked by pretreatment with external $Ca^{2+}$ free solution or by the addition of nifedifine. However, when slices were pretreated with the $Ca^{2+}$ ATPase inhibitor thapsigargin, NaOCl failed to induce membrane depolarization. In a calcium imaging technique using the $Ca^{2+}$-sensitive fluorescence dye fura-2, the $[Ca^{2+}]_i$ was found to be increased by NaOCl. These results indicate that NaOCl activates the excitability of SG neurons via the modulation of the intracellular calcium concentration, and suggest that ROS induces nociception through a central sensitization.

• Transactions on Electrical and Electronic Materials
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• 제13권6호
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• pp.310-316
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• 2012

A new method for early caries diagnosis was proposed and tested through a home-made optical examination system that used quantitative light fluorescence (QLF) and digital imaging fiber optic transillumination (FOTI) (DIFOTI), with light sources across a wide spectral range, from 350 nm to 1,000 nm. The front-illuminated infrared light scattering image (FIR) showed similar diagnostic abilities to that of DIFOTI. The FIR method was invented based on the observation that caries lesions lose the high transmittance and low scattering properties of benign enamel tissue. There are various methods for the early diagnosis of caries, such as visual examination, exploration, X-ray radiography, QLF, FOTI, and infrared fluorescence (diagnodent). Among them, methods based on optical properties are regarded as having the most potential. A comparative study was performed between the FOTI, QLF, diagnodent, optical coherence tomography, and FIR scattering image methods, using 20 extracted teeth samples with early caries. A scale of lesion measurement based on optical image contrast was proposed. The statistical analysis showed a significant correlation between the DIFOTI and FIR methods (r = 0.35, p < 0.05). However, the QLF and diagnodent methods showed little association with FIR images, as they have different detection principles as compared with FIR. Tomographic images obtained by OCT, using 1,330 nm super luminescent LED as a gold standard of tooth structure, verified that the FOTI and FIR results correctly represented the lack of homogeneity in dental tissue. The newly proposed FIR method attained similar diagnostic results to those of FOTI, but with an easier approach.

• Journal of Breast Cancer
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• 제21권4호
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• pp.447-452
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• 2018

Purpose: The recent trend in breast cancer treatment is to minimize axillary dissection. However, no pattern of axillary metastasis has been precisely established. The purpose of this study was to evaluate the metastatic lymphatic pattern using near-infrared fluorescence imaging with indocyanine green (ICG) in breast cancer with cytologically proven axillary metastasis. Methods: This was a prospective single-center study. We evaluated 147 patients with breast cancer involving cytologically proven axillary metastasis, and compared physiological and nonphysiological lymphatic metastasis. Results: We performed lymphatic mapping for 64 patients who exhibited level II lymphatic flow on near-infrared fluorescence imaging with ICG, and found that all had axillary metastasis: 51 patients who did not receive neoadjuvant chemotherapy (NAC) and 13 patients post-NAC. Of patients who did not receive NAC, 32 had physiological lymphatic metastasis and 19 had nonphysiological lymphatic metastasis. The risk factors for nonphysiological lymphatic metastasis were age ${\geq}55$ years, high Ki-67 index (>20%), and perinodal extension in both univariate and multivariate analysis (p<0.05). Conclusion: Patients with identified risk factors in cytologically-proven axillary metastasis who did not receive NAC may have nonphysiological lymphatic metastasis.

• Nuclear Engineering and Technology
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• 제56권1호
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• pp.301-308
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• 2024

Ceramic materials are being explored as alternatives to toxic lead sheets for radiation shielding due to their favorable properties like durability, thermal stability, and aesthetic appeal. However, crafting effective ceramics for radiation shielding entails complex processes, raising production costs. To investigate local viability, this study evaluated Malaysian ceramic tiles for shielding in diagnostic X-ray rooms. Different ceramics in terms of density and thickness were selected from local manufacturers. Energy Dispersive X-ray Fluorescence (EDXRF) and X-ray Fluorescence (XRF) characterized ceramic compositions, while Monte Carlo Particle and Heavy Ion Transport code System (MC PHITS) simulations determined Linear Attenuation Coefficient (LAC), Half-value Layer (HVL), Mass Attenuation Coefficient (MAC), and Mean Free Path (MFP) within the 40-150 kV energy range. Comparative analysis between MC PHITS simulations and real setups was conducted. The C3-S9 ceramic sample, known for homogeneous full-color structure, showcased superior shielding attributes, attributed to its high density and iron content. Notably, energy levels considerably impacted radiation penetration. Overall, C3-S9 demonstrated strong shielding performance, underlining Malaysia's potential ceramic tile resources for X-ray room radiation shielding.

• 한국동물생명공학회지
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• 제39권2호
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• pp.81-87
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• 2024

Background: Platelet-derived growth factor receptor alpha (PDGFRα) is essential for various biological processes, including fetal Leydig cell differentiation. The PDGFRα^EGFP mouse model, which expresses an eGFP fusion gene under the native Pdgfrα promoter, serves as a valuable resource for exploring PDGFRα's expression and function in vivo. This study investigates PDGFRα expression in adult testicular cells using PDGFRα^EGFP mouse model. Methods: Genotyping PCR and gel electrophoresis were used to confirm the zygosity of PDGFRα^EGFP mice. Histological examination and fluorescence imaging were used to identify PDGFRα expression within testicular tissue. Immunohistochemical analysis assessed the co-expression of PDGFRα with c-Kit, ANO-1, and TASK-1 in testicular cells. Results: Genotyping confirmed the heterozygous status of the mice, which is crucial for studies due to the embryonic lethal phenotype observed in homozygotes. Histological and fluorescence imaging revealed that PDGFRα⁺ cells were primarily located in the interstitial spaces of the testis, specifically within Leydig cells and peritubular myoid cells (PMCs). Immunohistochemical results showed PDGFRα co-localization with c-Kit and ANO-1 in Leydig cells and a complete co-localization with TASK-1 in both Leydig cells and PMCs. Conclusions: The findings demonstrate specific expression of PDGFRα in Leydig cells and PMCs in adult testicular tissue. The co-expression of PDGFRα with c-Kit, ANO-1, and TASK-1 suggests complex regulatory mechanisms, possibly influencing testicular function and broader physiological processes.