• Journal of Biomedical Engineering Research
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• v.26 no.1
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• pp.37-42
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• 2005

We construct and test the polarization-sensitive optical coherence tomography (PS-OCT) system for imaging porcine and human articular cartilages. PS-OCT is a new imaging technology that provides information regarding not only the tissue structures but tissue components that show birefringence such as collagen. In this study, we measure the cartilage thickness of the porcine joint and the phase retardation due to collagen birefringence. Also, we demonstrate that changes of the collagen fiber orientation could be detected by the PS-OCT system. Finally, differences between normal and damaged human articular cartilage are observed using the PS-OCT system, which is then compared with the regular histology pictures. As a result, the PS-OCT system is proven to be effective for diagnosis of the pathology related to the cartilage. In the future, this technology may be used for discrimination of the collagen types. When combined with endoscope technologies, the PS-OCT images may become a useful tool for in vivo tissue testing.

• Current Optics and Photonics
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• v.4 no.4
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• pp.330-335
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• 2020

We have investigated optimization of the working distance (WD) for a highly miniaturized imaging probe for endoscopic optical coherence tomography (OCT). The WD is the axial distance from the distal end of the imaging probe to its beam focus, which is demanded for dimensional margins of protective structures, operational safety, or full utilization of the axial imaging range of OCT. With an objective lens smaller than a few hundred micrometers in diameter, a micro-optic imaging probe naturally exhibits a very short WD due to the down-scaled optical structure. For a maximized WD careful design is required with the optical aperture of the objective lens optimally filled by the incident beam. The diffraction-involved effect was taken into account in our analysis of the apertured beam. In this study, we developed a simple design formula on the maximum achievable WD based on our diffraction simulation. It was found that the maximum WD is proportional to the aperture size squared. In experiment, we designed and fabricated very compact OCT probes with long WDs. Our 165-㎛-thick fiber-optic probes provided WDs of 3 mm or longer w ith reasonable OCT imaging performance.

• Korean Journal of Veterinary Research
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• v.61 no.1
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• pp.7.1-7.7
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• 2021

The levels of aflatoxin (AFT) and ochratoxin (OCT) were assessed at different seasons in raw materials, different feed manufacture processing stages, and animal feeds in feed mills in Korea implementing the hazard analysis and critical control point (HACCP) system. Two hundred samples were collected in all four seasons from five feed mills implementing the HACCP system and examined for AFT and OCT contents. The AFT and OCT levels were analysed by using HPLC method to provide information on raw material and product stage. The AFT content of raw ingredients in the spring season was highest in corn gluten (3.84 ppb) and lowest in corn (1.82 ppb) The AFT content of corn was highest in the winter season (2.17 ppb). The content of OCT in wheat was highest in the winter season. The amounts of AFT and OCT at processing stages were higher than in the raw materials or feed. In particular, AFT content was higher in the transfer stage (3.88 ppb) than in the mixing (2.86 ppb) or filling stages (3.45 ppb) in the summer season. The means of AFT and OCT level in laying hen feed was 3.41 ppb and 1.14 ppb for broiler feed, respectively. The means of AFT and OCT level in and broiler feeds was 3.44 ppb and 1.17 ppb for broiler feed, respectively.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.292-293
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• 2003

최근 생체의 단층영상 촬영기법으로 각광을 받고 있는 OCT (Optical Coherence Tomography)는 백색광 간섭계를 근간으로 하여 생체의 깊이 정보를 얻어낸다. 2-D 또는 3-D의 입체영상을 얻기 위해서는 1축 또는 2축의 횡방향 스캔이 필요하다. 횡방향 스캔 기법은 SEM (Scanning electron microscope)이나 공초점현미경 (Confocal microscope) 등에서 널리 사용되고 있으므로 기술적인 흥미는 적으나 축방향 (깊이 방향)의 정보 취득 방법은 OCT만의 특징으로 아직 기술적으로 해결 되어야될 부분이 많다. (중략)

• Proceedings of the Optical Society of Korea Conference
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• 2008.02a
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• pp.305-306
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• 2008

We have developed several types of optical sources for OCT applications. A high nonlinear PCF with end sealing and a short pulse laser were used to improve of OCT resolution. Additionally, an wavelength sept fiber laser was also developed for frequency-domain OCT.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.1
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• pp.24-30
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• 2011

We have developed a hand-held probe for an ophthalmic OCT system. The hand-held probe for imaging was designed to be compact and portable. The cornea and retinal images were acquired by replacing the objective lens at the front of the probe. To verify the performance of the hand-held OCT probe, we acquired two dimensional OCT image of the rat eye in vivo and reconstructed three dimensional rat eye rendering images. In vivo 3D OCT images were showed distinct structural information in the posterior and anterior chamber with minimal motion artifacts. Thereby, OCT imaging speed is suitable for an dynamic in vivo experiment.

• Journal of Veterinary Science
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• v.24 no.4
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• pp.34.1-34.12
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• 2023

Background: There has not been a thoroughly reported study of the comparison between spectral domain-optical coherence tomography (SD-OCT) with both ultrasound biomicroscopy (UBM) and gonioscopy on the evaluation of the iridocorneal angle (ICA) in dogs. Objectives: To investigate the diagnostic value of SD-OCT for the early detection of narrowing ICA by comparing and assessing inter-device agreement in anterior chamber angle (ACA) measurements obtained by SD-OCT and UBM, and ICA evaluations by gonioscopy. Methods: A total of 28 eyes from 28 client-owned dogs with normal intraocular pressure were included for examination. The ACA and angle opening distance (AOD) were measured from the SD-OCT and UBM images, and gonioscopy images were analyzed using the ICA grade and ZibWest angle index. Results: The mean ACA and AOD for SD-OCT were 28.31° ± 5.37° and 658.42 ± 219.90 ㎛, and for UBM, 28.34° ± 5.82° and 859.29 ± 221.80 ㎛, respectively. The mean difference in ACA between the average values of SD-OCT and UBM measurements was 0.03° with a 95% limit of agreement (LoA) span of 16.2°, indicating positive agreement; that in AOD was 200.85 ㎛ with a 95% LoA span of 1,110.95 ㎛, indicating poor agreement. The Pearson correlation coefficient of the ACA of SD-OCT and ZibWest indices of gonioscopy was 0.624, indicating strong agreement; that of UBM and gonioscopy was 0.43, indicating moderate agreement. Conclusions: SD-OCT is well tolerated by canine patients due to its non-contact method and might be an alternative option for early screening of ICA narrowing in clinical settings.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.3
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• pp.239-248
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• 2004

Optical coherence tomography(OCT) is high resolution imaging system which can see the cross section of microscopic organs in the living tissue. In this paper, we analyze the relation between the light source and the resolution of modulated signal in Michelson interferometer. We construct 1-D OCT signal processing hardware such as amplifiers, filters, and demodulate electronic signals from the photo detector. In order to get 2-D OCT image, the synchronization among optical delay line, sample stage and A/D converter is dealt with. In experiments, we verify analog and digital signal processing blocks which apply to the stacks of glasses. Finally we aquire high resolution 2-D OCT image with respect to the onion tissue. We expect that this result can be applied to the medical instrument through performance improvement.

• Laser Solutions
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• v.7 no.2
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• pp.11-18
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• 2004

We propose a novel application of optical coherence tomography (OCT) to monitor pit formation in laser irradiated optical storage materials. A multilayer optical storage recordable compact disk, is composed of multiple layers, each of different structure. Disks were irradiated with aQ-Switched Nd:YAG laser with an energy of 373 mJ. Post-irradiated disks were evaluated by OCT and those images were compared with optical microscopy. Our results indicate that OCT is a useful instrument to investigate pit formation in multilayer optical storage disks and might also provide information to optimize optical memory technology.

• Journal of Microbiology and Biotechnology
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• v.3 no.4
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• pp.252-255
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• 1993

Pseudomonas maltophilia N246 carrying on OCT plasmid grew on n-alkanes of 6 to 14 carbon atoms, but not on n-alkanes of more carbon atoms. P. maltophilia strains with and without OCT plasmid could utilize primary alcohols. aldehydes and fatty acids derived from n-alkane. The N246 strain could also utilize monocarboxylic and dicarboxylic acids, and terminal branched dimethyloctane. Unlike the genes of alcohol dehydrogenase and aldehyde dehydrogenase which were located on both the chromosome and the OCT plasmid, genes for the alkane hydroxylase components were located only on the OCT plasmid in P. maltophilia N246.