• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2275-2278
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• 2005

In this paper, a control algorithm for a servo manipulator is focused on. A servo manipulator system has been developed for remotely handling radioactive materials in a hot cell. It is driven by servo motors. The torque from a servo motor is transferred through a reducer to the corresponding axis. The PID control algorithm is a simple and effective algorithm for such application. However, since friction degrades the algorithm's performance, friction has to be considered and compensated. The major aberrations are the positional tracking errors and the limit cycle. The authors have considered a switching term to a conventional PID algorithm to reduce the friction's effect. It has been tested by a hardware test.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.897-898
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• 2008

Array comparative genomic hybridization (aCGH) has been used to detect chromosomal regions of amplifications or deletions, which allows identification of new cancer related genes. As aCGH, a large-scale spatial data, contains significant amount of noises in its raw data, it has been an important research issue to segment genomic DNA regions to detect its true underlying copy number aberrations (CNAs). In this study, we focus on applying a segmentation method to multiple data sets. We compare two different threshold values for analyzing aCGH data with CBS method [1]. The proposed threshold values are p-value or $Q{\pm}1.5IQR$ and $Q{\pm}1.5IQR$.

• Journal of Environmental Health Sciences
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• v.17 no.1
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• pp.110-119
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• 1991

This study was performed to investigate the applicability of 9 chromosome aberration and sister chromatid exchange analysis for the assessment of cytotoxicity and cytogenetic effects of cadmium. Induction of chromosome aberration and sister chromatid exchange in CHO-K1 cells and human peripheral lymphocytes by 2 hour-treatment of CdCl$_{2}$ with various concentrations was observed in relation to their frequencies and types of aberration. The frequency of chromosome aberration in CHO cells treated with CdCl$+{2}$ at G$_{1}$ was increased with dose-dependent manner. When human peripheral lymphocytes were treated with cadmium at G0 and harvested at 72 hours there after, the response was dose-dependent and all the aberrations were also chromatid types. There was no significant increase in frequencies of sister chromatid exchange in both CHO cells and human lymphocytes treated with different concentrations of cadmium. It was suggested that SCE analysis was not a good assessment method for cadmium toxicity.

• Environmental Mutagens and Carcinogens
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• v.15 no.2
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• pp.81-87
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• 1995

The clastogenic activity of capsaicin, a major pungent and irritating constituent of hot chili pepper, was evaluated in cultured human lymphocytes. Capsaicin (125, 250, and 500 $\mu$M) caused cytogenetic damage as determined by increased frequency of chromosome/chromatid aberrations compared to the solvent control. The mitotic indices were also decreased in a concentration-related manner in capsaicin-treated cells. Moreover, capsaicin suppressed [$^3$]thymidine incorporation into lymphocytes. The clastogenicity and cytotoxicity of capsaicin towards human lymphocytes were evident without an external metabolic activation system. Taken together, these findings suggest that capsaicin is a genotoxic agent and may thus represent a potential health hazard in humans.

• Molecules and Cells
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• v.37 no.2
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• pp.95-99
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• 2014

Cancer is unique amongst human diseases in that its cellular manifestations arise and evolve through the acquisition of somatic alterations in the genome. In particular, instability in the number and structure of chromosomes is a near-universal feature of the genomic alterations associated with epithelial cancers, and is triggered by the inactivation of tumour suppressor mechanisms that preserve chromosome integrity in normal cells. The nature of these mechanisms, and how their inactivation promotes carcinogenesis, remains enigmatic. I will review recent work from our laboratory on the tumour suppressor BRCA2 that addresses these issues, focusing on new insights into cancer pathogenesis and therapy that are emerging from improved understanding of the molecular basis of chromosomal instability in BRCA2-deficient cancer cells.

• Journal of Genetic Medicine
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• v.1 no.1
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• pp.11-16
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• 1997

A nine month old male child presenting degenerating right ulna (massive osteolysis) has been followed up for two years. The bone completely disappeared due to abscesses on the right forearm and without orthopedic or haematological complications. Repeated lymphocyte cultures showed somatic pairing (mostly chromosome pair 5), end to end association involving chromosome 14, 21, 21 and 16, and satellite enlargement in a high proportion of cells with an otherwise normal 46,XY karyotype. These observations are compared with 13 other types of orthopaedic patients, and we opine that cumulative picture of chromosomal aberrations appears to correspond with the present rare anomaly "Mono Ostolic Osteolysis" involving right ulna. None of the controls or any other orthopaedic anomaly studied hereunder exhibits this chromosomal picture.

• Proceedings of the Optical Society of Korea Conference
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• 1991.06a
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• pp.88-89
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• 1991

For the micro-lithography using a KrF excimer laser beam(λ=0.248${\mu}{\textrm}{m}$) a mirror system consisting of four spherical surfaces with reduction magnification 5$\times$ is designed. Initially the aplanat condition of the mirror system is considered. And for the further improved performance of the system the distortion free condition and flat field condition within Seidel 3rd order aberrations are added to the above condition. During the process of designing the computer-aided optimization technique is extensively employed. The spherical aberration, coma, field curvature and distortion of the optimized four-spherical mirror system are removed to the diffraction limit, and residual astigmatism and off-axial vignetting are not corrected enough.

• Current Optics and Photonics
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• v.3 no.6
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• pp.597-604
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• 2019

This study was performed to evaluate objective visual quality and ocular scattering in myopic refractive-surgery patients, compared to emmetropes. Optical vision-quality parameters (modulation transfer function (MTF) cutoff and Strehl ratio) and objective scattering index (OSI) were measured using an optical quality analysis system (OQAS II) based on the double-pass technique. In all subjects, the higher the MTF cutoff and Strehl ratio, the lower the OSI and ocular higher-order aberrations (HOAs). The MTF cutoff and Strehl ratio for the laser-assisted subepithelial keratectomy (LASEK) group were lower than those for the emmetropia group, while the OSI, ocular HOAs, and spherical aberration (SA) for the LASEK group were higher than those for emmetropia group. Ocular scattering would be one of the important factors in regard to visual quality. Therefore, the quality of the retinal image in the LASEK patients has been shown to reduce the quality of vision more than in the emmetropes.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.130-131
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• 2000

One of the more promising proposals for guiding and focusing neutral atoms involves dark hollow laser beams. When the frequency of the laser is detuned to the blue of resonance, the dipole force the atoms feel in the light confines them to the dark core where the atoms can be transported with minimal interaction with the light. The ability of the all-light atom guides to transport large number of ultracold atoms for long distances without physical walls leads to the possibility of a versatile tool for atom lithography, atom interferometry, atomic spectroscopy as well as for transporting and manipulating Bose-Einstein condensates. Furthermore since the atoms transported in all-light atom guides do not come into contact with matter, they can in principle be used to transport antimatter as well. The ability to vary the core size of the hollow beam makes the all-light atom guide potentially useful for focusing neutral atoms. The atoms could be focused as tight as the core size of the hollow beam at its waist. This new focusing scheme, called the atom funnel, would not show spherical and chromatic aberrations that conventional harmonic focusing suffers from. (omitted)

• Journal of the Optical Society of Korea
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• v.14 no.4
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• pp.424-430
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• 2010

In coherent anti-Stokes Raman scattering (CARS) microscopy reported until now, conventional microscope objectives are used, so that they are limited for introduction into a living body. Gradient-index (GRIN) rod lenses might be a solution for miniaturized microscope objectives for in-vivo CARS microscopy. However, due to the inherent large amount of chromatic aberration, GRIN rod lenses cannot be utilized for this purpose. CARS imaging catheter, composed of miniaturized microscope objective and fiber bundle, can be introduced into a living body for minimally invasive diagnosis. In order to design the catheter, we have to first investigate design requirements. And then, the optical design is processed with design strategies and intensive computing power to achieve the design requirements. We report the miniaturized objective lens system with diffraction-limited performance and completely corrected chromatic aberrations for an in-vivo CARS imaging catheter.