• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.6
• /
• pp.85-90
• /
• 2013

In this paper, 6bit SAR ADC tolerant to ionizing radiation is presented. Radiation tolerance is achieved by using the Dummy Gate Assisted (DGA) MOSFET which was proposed to suppress the leakage current induced by ionizing radiation and its comparing sample is designed with the conventional MOSFET. The designed ADC consists of binary capacitor DAC, dynamic latch comparator, and digital logic and was fabricated using a standard 0.35um CMOS process. Irradiation was performed by Co-60 gamma ray. After the irradiation, ADC designed with the conventional MOSFET did not operate properly. On the contrary, ADC designed with the DGA MOSFET showed a little parametric degradation of which DNL was increased from 0.7LSB to 2.0LSB and INL was increased from 1.8LSB to 3.2LSB. In spite of its parametric degradation, analog to digital conversion in the ADC with DGA MOSFET was found to be possible.

• Molecular & Cellular Toxicology
• /
• v.1 no.4
• /
• pp.275-280
• /
• 2005

Carbon tetrachloride ($CCl_4$) is well known hepatotoxicant. Its overdose cause severe centrilobular hepatic necrosis in human and experimental animals. We administered $CCl_{4}$ at low (0.2 mL/kg p.o.) and high (2 mL/kg p.o.) doses to mice. Mice were sacrificed at 24 h after administration. We evaluated liver toxicity by serum AST and ALT level and by microscopic observation. Using cDNA chip, we conducted gene expression analysis in liver. Mean serum activities of the hepatocellular leakage enzymes, ALT and AST, were significantly increased compare to control, respectively, in the low and high dose groups. H&E evaluation of stained liver sections revealed $CCl_{4}-related$ histopathological findings in mice. Moderate centrilobular hepatocellular necrosis was present in all $CCl_{4}$ treated mice. We found that gene expression pattern was very similar between low and high dose group. However, some stress related genes were differently expressed. These results could be a molecular signature for the degree of liver injury. Our data suggest that the degree of severity could be figure out by gene expression profiling.

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2003.11a
• /
• pp.90-95
• /
• 2003

Chemical management of annulus gas system is carried out for the purpose of ensuring the safety and reliability of the system via securing the integrity of the system, detecting the D$_2$O in-leakage of coolant and/or moderator, and reducing the radiation dose. Since the quality of CO_2$ gas, which is used as a filling gas for annulus gas system at CANDU plants, has a propound effect on the integrity of the system material and the radiation dose, CO_2$ gas of high quality is needed. If the quality of CO_2$ gas does not meet the specification, it may give rise to undesirable effect not only on the annulus gas system, but also on the environment due to the production of radioactive nuclei. Therefore, it is very important to check the impurities of CO_2$ gas. Based on this background, the inventories of C-14 and Ar-41 in CO_2$ gas that is supplied as annulus gas were estimated using the data on concentrations of the impurities of $CO_2$ such as C, N_2$ and Ar. The results of this study is expect to give useful information on optimization of CO_2$ impurities maintenance and management of gaseous radioactive wastes produced at CANDU plants.

• The Korean Journal of Physiology and Pharmacology
• /
• v.19 no.4
• /
• pp.357-363
• /
• 2015

The purpose of this study was to compare the inhibitory effect of bevacizumab on human Tenon's fibroblasts (HTFs) cultured from primary and recurrent pterygium. Cultured HTFs were exposed to 2.0, 5.0, 7.5, and 15.0 mg/mL concentration of bevacizumab for 24 hours. The 3-[4,5-dimethylthiazol- 2-yl]-2,5-diphenyl tetrazolium bromide and lactate dehydrogenase leakage assays were then performed to assess fibroblast metabolism and viability. The matrix metalloproteinase (MMP), procollagen type I C terminal propeptide (PIP), and laminin immunoassays were performed to examine extracellular matrix production. Changes in cellular morphology were examined by phase-contrast and transmission electron microscopy. Both metabolic activity and viability of primary and recurrent pterygium HTFs were inhibited by bevacizumab in a dose-dependent manner, especially at concentrations greater than 7.5 mg/mL. Both types of HTFs had significant decreases in MMP-1, PIP, and laminin levels. Distinctly, the inhibitory effect of bevacizumab on MMP-1 level related with collagenase in primary pterygium HTFs was significantly higher than that of recurrent pterygium. Significant changes in cellular density and morphology both occurred at bevacizumab concentrations greater than 7.5 mg/mL. Only primary pterygium HTFs had a reduction in cellular density at a bevacizumab concentration of 5.0 mg/mL. Bevacizumab inhibits primary and recurrent pterygium HTFs in a dose-dependent manner, especially at concentrations greater than 7.5 mg/mL. As the primary HTFs produces larger amounts of MMP-1 compared to recurrent HTFs, significant reduction in MMP-1 level in primary pterygium HTFs after exposure to bevacizumab is likely to be related to the faster cellular density changes in primary pterygium HTFs.

• Progress in Medical Physics
• /
• v.29 no.4
• /
• pp.143-149
• /
• 2018

To verify the correlations between the clinical outcomes and physical factors of short-course chemoradiotherapy (SCRT) and long-course chemoradiotherapy (LCRT) with delayed surgery in patients with rectal cancer. Seventy-two patients with rectal cancer were enrolled in this study. Nineteen patients were treated with SCRT (25 Gy, 5 fractions) by intensity-modulated radiation therapy (IMRT), and 53 patients were treated with LCRT (50.4 Gy, 28 fractions) by three-dimensional conformal radiation therapy (3DCRT). Various physical factors for the target and organs at risk (OARs) were calculated to compare the clinical outcomes. The organ equivalent dose (OED) and lifetime attributable risk (LAR) of bowels and bladders were similar between the SCRT and LCRT groups, whereas the values of femurs were higher in the LCRT group. The equivalent uniform dose and normal tissue complication probability were higher in the LCRT than the SCRT group for most organs. Treatment complications, including anastomotic leakage, bowel adhesion, and hematologic toxicity, were not significantly different between SCRT and LCRT groups. CIs were $0.84{\pm}0.2$ and $0.61{\pm}0.1$ for SCRT and LCRT, respectively. The CVIs were $1.07{\pm}0.0$ and $1.10{\pm}0.1$, and the HIs were $0.09{\pm}0.0$ and $0.11{\pm}0.1$ for SCRT and LCRT, respectively. The sphincter-saving rates were 89.5% and 94.3% for SCRT and LCRT, respectively. The complete pathologic remission rates were 21.1% and 13.2%, and the down-staging rates were 47.4% and 26.4% for SCRT and LCRT, respectively. SCRT with IMRT is comparable to conventional LCRT in both physical indexes and clinical outcome. The preoperative SCRT, compensated by IMRT, is an effective and safe modality.

• The Korean Journal of Pain
• /
• v.35 no.2
• /
• pp.129-139
• /
• 2022

C-arm fluoroscopy is a useful tool for interventional pain management. However, with the increasing use of C-arm fluoroscopy, the risk of accumulated radiation exposure is a significant concern for pain physicians. Therefore, efforts are needed to reduce radiation exposure. There are three types of radiation exposure sources: (1) the primary X-ray beam, (2) scattered radiation, and (3) leakage from the X-ray tube. The major radiation exposure risk for most medical staff members is scattered radiation, the amount of which is affected by many factors. Pain physicians can reduce their radiation exposure by use of several effective methods, which utilize the following main principles: reducing the exposure time, increasing the distance from the radiation source, and radiation shielding. Some methods reduce not only the pain physician's but also the patient's radiation exposure. Taking images with collimation and minimal use of magnification are ways to reduce the intensity of the primary X-ray beam and the amount of scattered radiation. It is also important to carefully select the C-arm fluoroscopy mode, such as pulsed mode or low-dose mode, for ensuring the physician's and patient's radiation safety. Pain physicians should practice these principles and also be aware of the annual permissible radiation dose as well as checking their radiation exposure. This article aimed to review the literature on radiation safety in relation to C-arm fluoroscopy and provide recommendations to pain physicians during C-arm fluoroscopy-guided interventional pain management.

• The Korean Journal of Zoology
• /
• v.16 no.1
• /
• pp.13-23
• /
• 1973

The changes in the quantitative distribution and in cytoplasmic granules of tongue mast cells and duodenal enterochromaffin cells in male albino rats were observed following oral administration of 40mg/kg body wt. isonicotinic acid hydraside (INH) and 20mg/kg body wt. pyridoxine. The results obtained are summarized as follows: 1. INH administered-rat showed a marked decrease in the number of mast cells, caused by leakage of cytoplasmic granules, while pyridoxine-rat showed increased the number of mast cells. 2. Similarly, INH-rat showed a marked decrease in the number of enterochromaffin cells. In the case of pyridoxine-rat, however, the number of enterochromaffin cells increased compared with that of the controls. 3. In view of the fact that a large dose of INH was harmful to the formation of mast cells and enterochromaffin cells. And considering that a moderate dose of pyridoxine stimulated the formation of the two kinds of cells and the amounts of cytoplasmic granules, it was concluded that pyridoxine might be concerned with the metabolism of secretory products, 5-Hydroxytryptamine.

• The Plant Pathology Journal
• /
• v.31 no.3
• /
• pp.316-321
• /
• 2015

A small cationic peptide (JH8944) was tested for activity against a number of pathogens of agricultural crops. JH8944 inhibited conidium growth in most of the tested plant pathogens with a dose of $50{\mu}g/ml$, although one isolate of Fusarium oxysporum was inhibited at $5{\mu}g/ml$ of JH8944. Most conidia of Fusarium graminearum were killed within 6 hours of treatment with $50{\mu}g/ml$ of JH8944. Germinating F. graminearum conidia required $238{\mu}g/ml$ of JH8944 for 90% growth inhibition. The peptide did not cause any damage to tissues surrounding maize leaf punctures when tested at a higher concentration of $250{\mu}g/ml$ even after 3 days. Liposomes consisting of phosphatidylglycerol were susceptible to leakage after treatment with 25 and $50{\mu}g/ml$ of JH8944. These experiments suggest this peptide destroys fungal membrane integrity and could be utilized for control of crop fungal pathogens.

• Journal of the Korean Society of Safety
• /
• v.30 no.5
• /
• pp.123-130
• /
• 2015

Wolsong Unit 2,3&4 has been performing a containment integrity test during power operation. This test could impact to the safe operation during test. If an accident occurs during pressure dropping phase, reactor trip can be delayed because of the increased pressure difference which causes a time delay to reach the trip set-point. On the contrary, if an accident occurs during pressure increasing phase, reactor trip could be accelerated because the pressure difference to the trip set-point decrease. Point Lepreau nuclear power plant, which installed GCLMS (Gross Containment Leakage Monitoring System) in 1990, has discontinued the test since 1992 due to these adverse effects. Therefore, we evaluated the risk to obviate the GCLMS test based on PWR's ILRT (Integrated Leak Rate Test) extension methodologies. The results demonstrate that risk increase rate is not high in case of performing only ILRT test at every 5 years instead of doing GCLMS test at every 1.5 years. In addition, the result shows that GCLMS test can be removed on a risk-informed perspective since risk increasement is in acceptable area of regulatory acceptance criteria.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.19 no.1
• /
• pp.7-12
• /
• 2006

Local minority carrier lifetime control by means of particle irradiation is an useful technology for Production of modern silicon Power devices. Crystal damage due to ion irradiation can be easily localized by choosing appropriate irradiation energy and minority tarrier lifetime can be reduced locally only in the damaged layer. In this work, proton irradiation technology was used for improving the switching characteristics of a un diode. The irradiation was carried out with various energy and dose condition. The device was characterized by current-voltage, capacitance-voltage, and reverse recovery time measurements. Forward voltage drop was increased to 1.1 V at forward current of 5 A, which was $120\%$ of its original device. Reverse leakage current was 64 nA at reverse voltage of 100 V, and reverse breakdown voltage was 670 V which was the same voltage as original device without irradiation. The reverse recovery time of device was reduced to about $20\%$ compared to that of original device without irradiation.