• International Journal of Oral Biology
• /
• v.38 no.4
• /
• pp.169-173
• /
• 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 $H_2O_2$.

• Journal of Information Display
• /
• v.6 no.4
• /
• pp.35-39
• /
• 2005

In this paper, we investigate the oxide cathodes for the development of reliable electron sources. Poisoning in oxide cathodes is one of the serious problems in achieving reliable electron emission. In particular, early poisoning induces poor life performance as will be demonstrated herein. The survivability of electron emission sources is significantly improved by high doping of high-speed activator. The robust oxide cathodes with 0.17 % Mg operating at about 1,050 K are expected to work for very long times (>100,000 hours). We suggest that this key idea will contribute to solving the basic problems in oxide cathodes such as poisoning or ion bombardment for high power or high frequency applications of electron sources.

• Journal of the Korean Society of Visualization
• /
• v.8 no.4
• /
• pp.48-53
• /
• 2010

Water-uptake through roots, is an essential process of the water flow in plants. Its visualization is very useful for understanding sap flow dynamics at whole plant level. In this study, the tips of Arabidopsis' root hairs were excised and exposed to repeated dehydration and rehydration processes. The water-refilling through individual xylem vessels was visualized using the synchrotron X-ray micro-imaging technique. The high temporal resolution ($2\;{\mu}m$) and beam intensity of the X-ray source allowed to acquisition of consecutive X-ray images of the water-refilling process up to 10 frames/sec. Various flow patterns were observed and the ascending speed of the water-air interfaces was analyzed. The relation between the water-rising height and ascending speed was also analyzed. The present results would provide better alternative for investigating sap flows in roots.

• Proceedings of the Optical Society of Korea Conference
• /
• 2009.10a
• /
• pp.117-118
• /
• 2009

• Proceedings of the Optical Society of Korea Conference
• /
• 2009.10a
• /
• pp.199-200
• /
• 2009

• Proceedings of the Optical Society of Korea Conference
• /
• 2008.07a
• /
• pp.281-282
• /
• 2008

• Nuclear Engineering and Technology
• /
• v.55 no.10
• /
• pp.3822-3830
• /
• 2023

The large-area Compton camera (LACC), featuring significantly high detection sensitivity, was developed for high-speed localization of gamma-ray sources. Due to the high gamma-ray interaction event rate induced by the high sensitivity, however, the multiplexer-based data acquisition system (DAQ) rapidly saturated, leading to deteriorated energy and imaging resolution at event rates higher than 4.7 × 10³ s^-1. In the present study, a new simultaneous multi-channel DAQ was developed to improve the energy and imaging resolution of the LACC even under high event rate conditions (10⁴-10⁶ s^-1). The performance of the DAQ was evaluated with several point sources under different event rate conditions. The results indicated that the new DAQ offers significantly better performance than the existing DAQ over the entire energy and event rate ranges. Especially, the new DAQ showed high energy resolution under very high event rate conditions, i.e., 6.9% and 8.6% (for 662 keV) at 1.3 × 10⁵ and 1.2 × 10⁶ s^-1, respectively. Furthermore, the new DAQ successfully acquired Compton images under those event rates, i.e., imaging resolutions of 13.8° and 19.3° at 8.7 × 10⁴ and 10⁶ s^-1, which correspond to 1.8 and 73 μSv/hr or about 18 and 730 times the background level, respectively.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.8 no.5
• /
• pp.418-426
• /
• 2003

To show a retina shape and thickness on the computer monitor, a laser has been used in Scanning Laser Ophthalmoscope(SLO) equipment using the traveling difference. This method requires exact synchronous control of laser traveling in optic system to show a clear 3-dimensional image of retina To obtain this image, this exact synchronism is very important for making the perfect plane scanning. In this study, a high speed and synchronous control of the galvanometer to make 3-dimensional retina image is presented. For the more, deadbeat load torque observer is added to the PI controller for compensation of the position error arisen in the high speed control. As a result, the proposed control system has a robust and precise response against the load torque variation appeared in high speed control. A stability and usefulness are verified by the computer simulation and the experiment.

• Proceedings of the IEEK Conference
• /
• 2002.07c
• /
• pp.1436-1439
• /
• 2002

In this paper, based on the data link model characterized by the spaceborne small SAR system, the high rate multi-channel data link module is designed including link storage, link processor, transmitter, and wide-angle antenna. The design results are presented with the performance analysis on the data link budget as well as the multi-mode data rate in association with the SAR imaging mode of operation from high resolution to the wide swath.

• Proceedings of the International Microelectronics And Packaging Society Conference
• /
• 2003.09a
• /
• pp.65-89
• /
• 2003

Next Highly sophisticated communication generation of the Advanced Electronics and Imaging processing society will require a vast information volume and super high speed signal transport and information instruction. This means that super high technology should be created for satisfying the demand. It's also required the high reliability of the communication system itself, It will be supported the new advanced packaging technology of the 3 Dimensional structured system and system integration technology. Here is introduced the new 3 Dimensional technology for IC nnd LSI packaging and Opt-electronics Packaging of ASET activity in Japan.