• Progress in Medical Physics
• /
• v.13 no.4
• /
• pp.224-228
• /
• 2002

Myocardial tagging technique such as spatial modulation of magnetization (SPAMM) allows the study of myocardial motion with high accuracy. However, the accuracy of the estimation of tag intersection can be affected by tagline spacing. The aim of this study was to investigate the relationship between tagline spacing of SPAMM image and tagging contrast-to-noise ratio (CNR) in in-vivo study. Two healthy volunteers were undergone electrocardiographically triggered MR imaging with SPAMM-based tagging pulse sequence at a 1.5T MR scanner. Horizontally modulated stripe patterns were imposed with a range from 3.6 to 9.6 mm of tagline spacing. Images of the left ventricle(LV) wall were acquired at the mid-ventricle level during cardiac cycle with FE-EPI (TR/TE = 5.8/2.2 msec, FA= 10$^{\circ}$. Tagging CNR for each image was calculated with a software which developed in our group. During contraction, tagging CNR was more rapidly decreased in case of narrow tagline spacing than in case of wide tagline spacing. In the same heart phase, CNR was increased corresponding with tagline spacing. Especially, at the fully contracted heart phase, CNR was more rapidly increased than the other heart phases as a function of tagline spacing. The results indicated that the optimization of tagline spacing provides better tagging CNR in order to analyze the myocardial motion more accurately.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2010.05a
• /
• pp.665-667
• /
• 2010

In this paper, the method to detect the IM(Inter Modulation) components of power amplifier is proposed by using frequency down-convertor. Output signals of power amplifier which is coupled by 20dB coupler and divided by power divider are applied to RF and LO of the frequency converter. It could be found the magnitude of IM components of power amplifier as a converted DC voltage which is come from the difference between 3th and 5th IM component. The detected DC voltage values are changed from 0.72V to 0.9V when 3rd IM component level changed from -26.4dBm to +2.15dBm and 5th IM component level changed from -34.2dBm to -12.89dBm as the Vgs of 3W power amplifier is changed.

• Fisheries and Aquatic Sciences
• /
• v.20 no.9
• /
• pp.23.1-23.9
• /
• 2017

Two distinct cDNAs encoding aquaporins (mmAQPs 1a and 3a) were isolated and characterized from mud loach Misgurnus mizolepis. The identified mud loach AQP cDNAs encode for polypeptides of 260 and 302 amino acids. Topology predictions confirmed six putative membrane-spanning domains connected by five loops and the N- and C-terminal domains being cytoplasmic. The mud loach AQPs 1a and 3a showed broad distribution in multiple tissues including immune-responsive tissues as well as osmoregulatory tissues. Hence, the diversity of AQP distribution and expression possibly indicated its differential functions in the regulation of fluid movement in response to environmental stimuli. The transcription of mmAQP genes was differentially modulated by immune challenges. In particular, the mmAQP3a expression level in the liver was more responsive to immune challenges than that of mmAQP1a. Taken together, fish stimulation or infection resulted in significant modulation of mud loach AQP genes, suggesting potential functional roles of these proteins in piscine pathophysiological process.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.43 no.3 s.309
• /
• pp.51-59
• /
• 2006

In this paper, we propose an excellent ultrasonic transceiver system based on a QPSK modulation technique for underwater communication. The transmitter sends a still image at the level of 187dB re $1{\mu}Pa/V@1m$ through a power amplifier by driving an ultrasonic sensor. The receiver performs digital conversion at the 100kHz sampling frequency, demodulation and decoding process for the image sent from the transmitter through the underwater communication. We have shown that the processed image at the receiver is almost the same as the orignal one. The maximum detection distance of the system proposed in this paper is approximately 1.17km. To cope with the difficulties of transmission loss, this paper proposes, implements and analyzes important parameters of sensors and circuits used in the system. Most of the underwater communication has focused on the transmission of audio signal, but this paper suggests an efficient underwater communication system for still image transmission.

• Journal of Satellite, Information and Communications
• /
• v.8 no.4
• /
• pp.75-80
• /
• 2013

In this paper, the Ka-band maritime satellite communication systems for mobile terminals are proposed. The design includes the link budget analysis, determination of modulation and coding schemes and the overall structure of a transmitter. To avoid the harmful effects on the existing DVB-S2 services, the proposed maritime satellite system using the same spectrum with DVB-S2 at the same time employs the very wideband spreading transmission. Additionally, omni-directional low-gain antennas should be equipped in a mobile terminal to reduce the system cost. These two considerations limit the maximum transmission rate of the proposed system. Due to the limitations, the proposed system includes 36 dB or 39 dB spreading gain depending on the modulation scheme and a link-adaptive repetition method depending on the level of rain attenuation. To support short packets with minimal performance loss, the turbo code used in 3GPP instead of LDPC(low density parity check code) is adopted. By combining them, the overall structure of low-rate maritime satellite communication system is designed.

• Proceedings of the Korean Society of Medical Physics Conference
• /
• 2002.09a
• /
• pp.360-362
• /
• 2002

Myocardial tagging technique such as spatial modulation of magnetization (SPAMM) allows the study of myocardial motion with high accuracy. Tagging contrast of such a tagging images can affect to the accuracy of the estimation of tag intersection in order to analyze the myocardial motion. Tagging contrast can be affected by tagline spacing. The aim of this study was to investigate the relationship between tagline spacing of SPAMM image and tagging contrast-to-noise ratio (CNR) experimentally. One healthy volunteer was undergone electrocardiographically triggered MR imaging with SPAMM-based tagging pulse sequence at a 1.5T MR scanner (Gyroscan Intera, Philips Medical System, Netherland). Horizontally modulated stripe patterns were imposed with a range from 3.6mm to 9.6mm of tagline spacing. Images of the left ventricle (LV) wall were acquired at the mid-ventricle level during cardiac cycle with FEEPI (TR/TE/FA=5.8/2.2/10). Tagging CNR for each image was calculated with a software which developed in our group. During contraction, tagging CNR was more rapidly decreased in case of short tagline spacing than in case of long tagline spacing. In the same heart phase, CNR was increased corresponding with tag line spacing. Especially, at the fully contracted heart phase, CNR was more rapidly increased than the other heart phases as a function of tagline spacing.

• Journal of electromagnetic engineering and science
• /
• v.10 no.1
• /
• pp.18-24
• /
• 2010

A Ka-band microstrip array antenna for wide-range detection of moving targets is analyzed through a photonicassisted reactive-near-field characterization technique. The antenna array employs a 3-dB-tapered feed network to suppress the sidelobe level while retaining a wide azimuth beamwidth for a wide detection range. The relative nearelectric field patterns of the array and its 3-dB-tapered feed lines have been measured using an electro-optic fieldmapping technique for minimally invasive millimeter-wave sensing. A number of typical limitations on the technique, involving bandwidth, low signal-modulation depth, and high laser-induced noise in high-frequency applications, have been overcome by suppressing the carrier portion of the optical interrogation beam.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.14 no.9
• /
• pp.936-943
• /
• 2003

The miniaturized wireless endoscope consists of CMOS Image sensor, FPGA, LED, Battery, DC to DC Converter, Antenna and Transmitter. FSK transmitter is designed and fabricated with 10 mm(diameter)${\times}$23 mm(thickness) dimension considering the maximum permission exposure(MPE), system size, power consumption, linearity and modulation method. Experimental results is - 3.67 dBm output power level, 20 MHz frequency deviation, and - 99 dBc/Hz(@100 kHz offset) phase noise at 1.2 GHz. From the in-vivo experiment, the designed FSK transmitter has a acceptable capability for wireless endoscope.

• Journal of Life Science
• /
• v.16 no.3 s.76
• /
• pp.433-441
• /
• 2006

Polyamines are essential for the normal cell growth and differentiation. They are also known to have paradoxical dual effects on cell proliferation. In this paper we show that the excess amount of polyamines induces apoptosis through the modulation of calcium signaling in LNCaP human prostate cancer cells. Polyamines, particularly spermidine and spermine, stimulated cell proliferation at a lower concentration (under 10 ${\mu}M$), but it inhibited cell viability at a higher concentration (40 ${\mu}M$). The levels of intracellular $Ca^{2+}$ concentration were increased only at a high concentration of polyamines treatment without any noticeable changes at lower concentrations. Nifedipine did not alter the increase of polyamine-induced $Ca^{2+}$ levels, but flufenamic acid totally abolished the increase of intracellular $Ca^{2+}$ levels. These results mean that polyamines induce $Ca^{2+}$ influx from the surroundings through nonselective cation channels on the cell membrane. The expression of Bcl-2 protein was almost completely blocked, but the level of Bax protein was increased dramatically in the cells treated with high concentration of polyamine. The present study shows that polyamines at a high concentration induce apoptosis through the modulation of intracellular calcium signaling. The increase of intracellular calcium level induced by polyamines, was possibly a result from the extracellular calcium influx through the nonselective cation channels.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.2
• /
• pp.203-209
• /
• 2013

Digital Radiography (DR) has improved a quality of resolution based on a wide dynamic range, high detective quantum efficiency (DQE), and modulation transfer function (MTF), compared with film/screen(F/s). Unlike expectation that a low level of radiation can be used in examination, high level of signal to noise ratio(SNR) due to over-exposure caused increase of exposed dose to patients. Also, the auto exposure control (AEC) using Kilovolage(kVp) in F/S can cause over-exposure. Hence, in this study, we proposed a proper method for using DR, in which effect of tubing Kilovolage on device's image, DR MTF measurement with changes of tubing current (mA), and the quantitative evaluation of skull phantom captured images' PSNR were evaluated. Changes of contrast with tubing Kilovolage can be improved by retouching, and MTF changes according to tubing current(1.41~1.39 lp/mm in 50% area, and 3.19~2.8 lp/mm in 10% area) does not influence on resolution of image. As a result, high tubing Kilovoltage, and tubing current will be suitable to use of DR.