• International Journal of Oral Biology
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• v.38 no.4
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• pp.169-173
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• 2013

HyPer is the genetically encoded biosensor of intracellular hydrogen peroxide ($H_2O_2$), the most stable of the reactive oxygen species (ROS) generated by living cells. HyPer has a high sensitivity and specificity for detecting intracellular $H_2O_2$ by confocal laser microscopy. However, it was not known whether high speed ratiometric imaging of $H_2O_2$ by HyPer is possible. We thus investigated the sensitivity of HyPer in detecting changes to the intracellular $H_2O_2$ levels in HEK293 and PC12 cells using a microfluorometer imaging system. Increase in the HyPer ratio were clearly evident on stimulations of more than $100{\mu}M$ $H_2O_2$ and fast changes in the HyPer ratio were observed on ratiometric fluorescent images after $H_2O_2$ treatment. These results suggest that HyPer is a potent biosensor of the fast temporal production of intracellular $H_2O_2$.

• Proceedings of the KSMRM Conference
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• 2004.09a
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• pp.44-44
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• 2004

• Proceedings of the KSMRM Conference
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• 2005.09a
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• pp.68-68
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• 2005

• Korean Journal of Optics and Photonics
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• v.14 no.6
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• pp.606-612
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• 2003

The self-imaging effect or lensless imaging effect of a phase line grating is theoretically analyzed by using Fresnel diffraction theory, then experimentally investigated. The self-imaging distance $z_{T,p}$, that is the imaging distance being perfectly copied from the phase distribution of the phase grating to its intensity distribution with the magnification of 1X, can be uniquely defined as the (4n-3) $z_{T,a}$/4(n=positive integers), where rte is the well-known self-imaging distance of an amplitude grating. When the coherent laser beam is illuminated at the phase grating, the self-imaged images were obtained at $z_{T,p}$= $z_{T,a}$/4 and $z_{T,p}$=5 $z_{T,a}$/4 without any optics. On the other side, the phase-reversed self-imaging was obviously observed at $z_{T,p}$ = 3 $z_{T,a}$/4. The visibility of self-imaged images of a phase line grating as a function of the number of slits of the input grating was measured by the FFT(Fast Fourier Transform) results of the self-imaging images. As a result a stationary maximum visibility of V = 0.10 can be obtained from a grating with more than 15 slit pairs.n 15 slit pairs.

• 대한핵의학회:학술대회논문집
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• 2002.05a
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• pp.25-27
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• 2002

With the advent of multidetector-row CT, lung cancer imaging is much more promising than before. However, the effectiveness of multidetector-row CT in making an initial diagnosis, staging, and evaluating post-treatment changes of lung cancer still remains to be proved. Fast imaging along with volumetric data set and attendant multi-planar imaging provide much more details on the anatomic changes and pathology associated with lung cancer. However, with images showing anatomic and pathologic changes only, radiologists confront with several questions the answers of which may help evaluate lung cancer more thoroughly. The frequent questions that I have in dally practice of chest CT interpretation are as follows.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.307-308
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• 2006

In recent, displays have very good properties at high luminance, fast response, and size. Also They have good quality in terms of color according to the development of the gamut extension and color reproduction. However, despite these merits, there is a characteristic that at a high luminance display, observer perceive the different color from the originally re-producted color due to the change of perceived luminance in human visual system. In this paper, we propose a model that is the hue shift phenomenon between a normal display and a high luminance display, and then an algorithm which compensate the color between two devices, so that observer can perceive the same color.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.5
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• pp.571-579
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• 1999

In this paper, a Hadamard transform imaging spectrometer(HTIS) is proposed by using a grill spectrometer. And we reconfigure the system by using the grill sectrometer which uses a left cyclic S-matrix instead of the conventional right cyclic one. Then, we model the Hadamard transform imaging spectrometer and apply the mask characteristics compensation method, i.e. $ {T}^{-1}$ method, to complete fast algorithm. Also, through computer simulations the superiority of the proposed system in this paper to the conventional Hadamard transform spectrometer(HTS) is proved and the performance of the two systems are compared by introducing average mean square error(AMSE) as the algebraic criterion.

• Progress in Medical Physics
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• v.33 no.2
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• pp.11-24
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• 2022

X-ray detection has widely been applied in medical diagnostics, security screening, nondestructive testing in the industry, etc. Medical X-ray imaging procedures require digital flat detectors operating with low doses to reduce radiation health risks. Recently, metal halide perovskites (MHPs) have shown great potential in high-performance X-ray detection because of their attractive properties, such as strong X-ray absorption, high mobility-lifetime product, tunable bandgap, low-temperature fabrication, near-unity photoluminescence quantum yields, and fast photoresponse. In this paper, we review and introduce the development status of new perovskite X-ray detectors and imaging, which have emerged as a new promising high-sensitivity X-ray detection technology. We discuss the latest progress and future perspective of MHP-based X-ray detection in medical imaging. Finally, we compare the conventional detection methods with quantum-enhanced detection, pointing out the challenges and perspectives for future research directions toward perovskite-based X-ray applications.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.86.2-86.2
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• 2013

Ellerman bombs(EBs) are emission features at the wings of the H alpha spectral line. They are believed to be a kind of a magnetic reconnection feature in the low chromosphere or near photosphere. It was previously reported that surges often occur in association with EBs. However, previous observations were restricted to imaging observation. Using Fast Imaging Solar Spectrograph installed in New Solar Telescope at Big Bear Solar Observatory, California, we observed 5 EBs and associated surges with high-spatial and high-spectral resolutions. In this presentation, we will show the results and discuss the physical properties.

• Proceedings of the KSMRM Conference
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• 2001.11a
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• pp.165-165
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• 2001

Purpose： To obtain quantitative diffusion-tensor anisotropy information of human cerebral structu using turbo STEAM diffusion-tensor imaging. Method： Quantitative diffusion anisotropy MR images were obtained in 7 healthy adults using turbo STEAM sequence and a combination of tetrahedral and orthogonal diffusi gradients. Both relative anisotropy(RA) and fractional anisotropy(FA) values were measured various brain regions. The anisotropy index was then compared with the reported valu resulting from EPI-based diffusion tensor imaging.