• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.1
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• pp.313-324
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• 1997

The aim of the present study was to describe an safe and convenient method for the early detection of enamel caries using laser fluorescence. Fluorescence from natually carious lesion of human teeth illuminated by an argon laser(488nm) was observed and photographed using barrier filter. Intact enamel was found to fluorescence with a yellowish light. Whereas, incipient caries lesions in the enamel were dearly visible as dark areas in contrast to the fluorescence surroundings. For evaluation of accuracy of this method, lesion depth measured by the laser fluorescence in light microscope was compared with that polarizing microscope. The results from the present study can be summarized as follows : 1. Enamel caries of smooth surface was observed as pale white spot and undefined outline in ordinary light. Whereas, lesion was clearly visible as dark spot in laser fluorescence. 2. There was no difference between ordinary light view and laser fluorescence in occlusal surface and interproximal surface. 3. There was no significant difference between the lesion depth observed by laser fluorescence with light microscope and polarizing microscope. Apparent correlation exists between two groups.

• Applied Chemistry for Engineering
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• v.33 no.1
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• pp.17-27
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• 2022

Fluorescence imaging is widely used to image cells or small animals due to its high temporal and spatial resolution. Because conventional fluorescence imaging uses visible light, the penetration depth of light within the tissue is low, phototoxicity may occur due to visible light, and the detection sensitivity is lowered due to interference by background autofluorescence. In order to overcome this limitation, long-wavelength light should be used, and fluorescence imaging using near-infrared-I (NIR-I) in the region of 700~900 nm has been developed. To further improve imaging quality, researchers are interested in using a longer wavelength light, near-infrared-II (NIR-II) ranging from 1000 to 1700 nm. In the NIR-II region, light scattering is further minimized, and the penetration depth of light in the tissue is improved up to about 10 mm, and autofluorescence of the tissue is reduced, enabling high sensitivity and resolution fluorescence imaging. In this review, among various NIR-II fluorescence imaging probes, inorganic nanoparticle-based probes with excellent photostability and easily tunable emission wavelength were described, focusing on single-walled carbon nanotubes, quantum dots, and lanthanide nanoparticles.

• Journal of Biosystems Engineering
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• v.35 no.2
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• pp.124-131
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• 2010

Chlorophyll fluorescence has been researched for assessing fruit post-harvest quality and condition. The objective of this preliminary research was to investigate the potential of fluorescence spectroscopy for measuring apple fruit quality. Ultraviolet (UV) and blue light was used as an excitation source for inducing fluorescence in apples. Fluorescence spectra were measured from 'Golden Delicious' (GD) and 'Red Delicious' (RD) apples using a visible/near-infrared spectrometer after one, three, and five minutes of continuous UV/blue light illumination. Standard destructive tests were performed to measure fruit firmness, skin and flesh color, soluble solids and acid content from the apples. Calibration models for each of the three illumination time periods were developed to predict fruit quality indexes. The results showed that fluorescence emission decreased steadily during the first three minutes of UV/blue light illumination and was stable within five minutes. The differences were minimal in the model prediction results based on fluorescence data at one, three or five minutes of illumination. Overall, better predictions were obtained for apple skin chroma and hue and flesh hue with values for the correlation coefficient of validation between 0.80 and 0.90 for both GD and RD. Relatively poor predictions were obtained for fruit firmness, soluble solids content, titrational acid, and flesh chroma. This research has demonstrated that fluorescence spectroscopy is potentially useful for assessing selected quality attributes of apple fruit and further research is needed to improve fluorescence measurements so that better predictions of fruit quality can be achieved.

• Bulletin of the Korean Chemical Society
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• v.22 no.9
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• pp.975-978
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• 2001

A novel poly[9,10-diphenylanthracene-4',4"-ylenevinylene-3,6-(N-2-ethyl hexyl)carbazole] containing alternate diphenylanthracene and carbazole unit was synthesized by the Wittig reaction. The obtained polymer was soluble in common organic solvents and thermally stable up to 380 $^{\circ}C.$ The polymer gives rise to bright blue fluorescence both in solution and in thin solid films. The light emitted from the device (ITO/polymer/Al) was greenish-blue in color and clearly visible in daylight.

• Journal of Korean Neurosurgical Society
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• v.58 no.6
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• pp.513-517
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• 2015

Objective : Microscopic indocyanine green (ICG) angiography is useful for identifying the completeness of aneurysm clipping and the preservation of parent arteries and small perforators. Neuroendoscopy is helpful for visualizing structures beyond the straight line of the microscopic view. We evaluated our prototype of endoscopic ICG fluorescence angiography in swine, which we developed in order to combine the merits of microscopic ICG angiography and endoscopy. Methods : Our endoscopic ICG system consists of a camera, a light source, a display and software. This system can simultaneously display real-time visible and near infrared fluorescence imaging on the same monitor. A commercially available endoscope was used, which was 4 mm in diameter and had an angle of $30^{\circ}$. A male crossbred swine was used. Results : Under general anesthesia, a small craniotomy was performed and the brain surface of the swine was exposed. ICG was injected via the ear vein with a bolus dose of 0.3 mg/kg. Visible and ICG fluorescence images of cortical vessels were simultaneously observed on the display monitor at high resolution. The real-time merging of the visible and fluorescent images corresponded well. Conclusion : Simultaneous visible color and ICG fluorescent imaging of the cortical vessels in the swine brain was satisfactory. Technical improvement and clinical implication are expected.

• Journal of Korean Academy of Oral Health
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• v.41 no.4
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• pp.290-295
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• 2017

Objectives: Dental plaque emits red fluorescence under a visible blue light near the ultra-violet end of the light spectrum. The fluorescence characteristics of each microorganism have been reported in several studies. The aim of this study was to evaluate changes in red fluorescence of oral microorganisms that is affected by blood in the culture media. Methods: The gram-positive Actinomyces naeslundii (AN, KCTC 5525) and Lactobacillus casei (LC, KCTC 3109) and gram negative Prevotella intermedia (PI, KCTC 3692) that are known to emit red fluorescence were used in this study. Each bacterium was activated in broth and cultivated in different agar media at $37^{\circ}C$ for 7 days. Tryptic soy agar with hemin and vitamin $K_3$ (TSA), TSA with sheep blood (TSAB), basal medium mucin (BMM) medium, and BMM with sheep blood (BMMB) were used in this study. Fluorescence due to bacterial growth was observed under 405-nm wavelength blue light using the quantitative light-induced fluorescence-digital (QLF-D) device. The red, green, and blue fluorescence values of colonies were obtained using image-analysis software and the red to green ratio (R/G value) and red to total RGB ratio (R/RGB value) were calculated for quantitative comparison. Results: The QLF-D images of the AN, LC, and PI colonies showed red fluorescence in all media, but the fluorescence of all bacteria was reduced in TSA and BMM media, compared with in TSAB and BMMB media. Both the R/G and the R/RGB values of all bacteria were significantly reduced in growth media without blood (P<0.001). Conclusions: Based on this in vitro study, it can be concluded that red fluorescence of oral bacteria can be affected by growth components, especially blood. Blood-containing medium could be a significant factor influencing red fluorescence of oral bacteria. It can be further hypothesized that bleeding in the oral cavity can increase the red fluorescence of dental plaque.

• Fisheries and Aquatic Sciences
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• v.17 no.4
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• pp.479-486
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• 2014

To evaluate their potential utility as an ornamental organism, novel transgenic marine medaka Oryzias dancena strains with a highly vivid fluorescent phenotype were established through transgenesis of a cyan fluorescent protein gene (cfp) driven by the endogenous fast skeletal myosin light chain 2 gene (mlc2f) promoter. The transgenic marine medaka strains possessed multiple copies of transgene integrants and passed their fluorescent transgenes successfully to subsequent generations. Transgenic expression in skeletal muscles at both the mRNA and phenotypic levels was, overall, dependent upon transgene copy numbers. In the external phenotype, an authentic fluorescent color was dominant in the skeletal muscles of the transgenic fish and clearly visible to the unaided eye. The phenotypic fluorescent color presented differentially in response to different light-irradiation sources; the transgenics displayed a yellow-green color under normal daylight or white room light conditions, a strong green-glowing fluorescence under ultraviolet light, and a cyan-like fluorescence under blue light from a light-emitting diode.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4052-4058
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• 2012

The composite photocatalyst, N-$TiO_2$ loaded with $Ni_2O_3$, was prepared by $N_2$ plasma treatment. X-ray diffraction, X-ray fluorescence, $N_2$ adsorption, UV-vis spectroscopy, photoluminescence, and X-ray photoelectron spectroscopy were used to characterize the prepared $TiO_2$ samples. The results indicated that the band gap energy was decreased obviously by nitrogen doping, whereas loading of $Ni_2O_3$ did not influence the band gap and visible light absorption. The photocatalytic activities were tested in the degradation of 2,4,6-trichlorophenol (TCP) under visible light. The photocatalytic activity and stability of composite photocatalyst were much higher than that of catalyst modified with nitrogen or $Ni_2O_3$ alone. The synergistic effect of doping nitrogen and $Ni_2O_3$ over $TiO_2$ was investigated.

• Ceramist
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• v.22 no.3
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• pp.281-300
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• 2019

Surface enhanced Raman scattering (SERS) was first discovered in 1974 by an unexpected Raman signal increase from Pyridine adsorbed on rough Ag electrode surfaces by the M. Fleishmann group. M. Moskovits group suggested that this phenomenon could be caused by surface plasmon resonance (SPR), which is a collective oscillation of free electrons at the surface of metal nanostructures by an external light source. After about 40 years, the SERS study has attracted great attention as a biomolecule analysis technology, and more than 2500 new papers and 500 review papers related to SERS topic have been published each year in recently. The advantages of biomaterials analysis using SERS are as follows; ① Molecular level analysis is possible based on unique fingerprint information of biomolecule, ② There is no photo-bleaching effect of the Raman reporters, allowing long-term monitoring of biomaterials compared to fluorescence microscopy, ③ SERS peak bandwidth is approximately 10 to 100 times narrower than fluorescence emission from organic phosphor or quantum dot, resulting in higher analysis accuracy, ④ Single excitation wavelength allows analysis of various biomaterials, ⑤ By utilizing near-infrared (NIR) SERS-activated nanostructures and NIR excitation lasers, auto-fluorescence noise in the visible wavelength range can be avoided from in vivo experiment and light damage in living cells can be minimized compared to visible lasers, ⑥ The weak Raman signal of the water molecule makes it easy to analyze biomaterials in aqueous solutions. For this reason, SERS is attracting attention as a next-generation non-invasive medical diagnostic device as well as substance analysis. In this review, the principles of SERS and various biomaterial analysis principles using SERS analysis will be introduced through recent research papers.

• The Journal of the Korean dental association
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• v.49 no.8
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• pp.461-471
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• 2011

The detection of carious lesions is a key point to apply appropriate preventive measures or operative treatment of dental caries. A laser fluorescence device DIAGNOdent$^{(R)}$ (KaVo, Biberach, Germany) has also been shown to be of additional clinical value in the detection of initial caries. This report focus on the DIAGNOdent$^{(R)}$ for caries detection. DIAGNOdent$^{(R)}$ irradiate visible red light at a wavelength of 655 nm to elicit near-infrared fluorescence from caries lesion. This device is known as a reproducible method for caries detection, with good sensitivity and specificity especially for caries detection on occlusal and accessible smooth surfaces. DIAGNOdent$^{(R)}$ tended to be more sensitive method of detecting occlusal dentinal caries, however, showed more false-positive diagnoses than the visual inspection. So Clinician should not use the device as a clinician's primary diagnostic method and it is recommended that the device should be used in the decision-making process in relation to the diagnosis of caries as a second opinion in cases of doubt after visual inspection. The trend of modern dentistry would be a preventive approach rather than invasive treatment of the disease. This is possible only with early detection and respective preventive measures, DIAGNOdent$^{(R)}$ can help the changes.