• Radiation Oncology Journal
• /
• v.21 no.3
• /
• pp.227-237
• /
• 2003

Purpose: The human chronic myelogenous leukemia cell line, K562, expresses the chimeric bcr-abl oncoprotein, whose deregulated protein tyrosine kinase activity antagonizes via DNA damaging agents. Previous experiments have shown that nanomolar concentrations of herbimycin A (HWA) coupled with X-irradiation have a synergistic effect in inducing apoptosis in the Ph-positive K562 leukemia cell line, but genistein, a PTK inhibitor, is non selective for the radiation-induced apoptosils on $p210^{bcr/abl}$ protected K562 cells. In these experiments, the cytoplasmic signal transduction pathways, the Induction on a number of transcription factors and the differential gene expression in this model were investigated. Materials and Methids: K562 cells in the exponential growth phase were used in this study. The cells were irradiated with 0.5-12 Gy, using a 6 Mev Linac (Clinac 1800, Varian, USA). Immediately after irradiation, the cells were treated with $0.25/muM$ of HMA and $25/muM$ of genistein, and the expressions and the activities of abl kinase, MAPK family, NF- kB, c-fos, c-myc, and thymidine kinase1 (TK1) were examined. The differential gene expressions induced by PTK inhibitors were also investigated. Results: The modulating effects of herbimycin A and genistein on the radiosensitivity of K562 cells were not related to the bcr-abl kinase activity. The signaling responses through the MAPK family of proteins, were not involved either in association with the radiation-induced apoptosis, which is accelerated by HMA, the expression of c-myc was increased. The combined treatment of genistein, with irradiation, enhanced NF- kB activity and the TK1 expression and activity. Conclusion: The effects of HMA and genistein on the radiosensitivity on the K562 cells were not related to the bcr-abl kinase activity in this study, another signaling pathway, besides the WAPK family responses to radiation to K562 cells, was found. Further evaluation using this model will provide valuable information for the optional radiosensitization or radioprotection.

• Food Science and Preservation
• /
• v.23 no.1
• /
• pp.139-143
• /
• 2016

This study investigated the effect of electron beam (EB) treatment on the microbial reduction of dried laver (Porphyra tenera) and identified EB-resistant bacteria from the treated dried laver. After EB treatments of 4 kGy and 7 kGy, the numbers of total bacteria and EB-resistant bacteria were measured using tryptic soy agar and mannitol salt agar, respectively. The morphological and biochemical characteristics of each isolated EB-resistant bacteria were investigated and these bacteria were identified. Compared to the control ($1.5{\pm}0.2){\times}10^6CFU/g$, the total bacterial number was significantly decreased to ($5.4{\pm}0.5){\times}10^4CFU/g$ and ($1.1{\pm}0.6){\times}10^4CFU/g$ after EB treatments of 4 kGy and 7 kGy, respectively. With a higher EB dosage, the number of red colonies was almost same, whereas the number of yellow colonies was significantly decreased to ($3.3{\pm}1.2){\times}10^3CFU/g$ and 0 CFU/g for 4 kGy and 7 kGy, respectively. All red and yellow colonies were gram-positive cocci, catalase-positive, and resistant to 3% and 5% NaCl media. From the 16S rDNA sequence analysis, yellow and red colonies were identified as either Micrococcus flavus or M. luteus, with 99% similarity for the yellow colonies, and Deinococcus proteolyticus and D. piscis, with 99% and 97% similarity for the red colonies, respectively.

• The Korean Journal of Nuclear Medicine
• /
• v.37 no.3
• /
• pp.190-198
• /
• 2003

Purpose: To evaluate radiation sensitivity of dendritic cells in comparison with lymphocytes. Materials and methods: T lymphocytes captured from peripheral blood were irradiated by 0 Gy, 10 Gy, 30 Gy. Apoptosis was measured by flowcytometry for staining of Annexin V 4 hours after irradiation. Immature and mature dendritic cells processed from blood hematopoietic stem cell were irradiated by 0 Gy, 10 Gy, 30 Gy, 100 Gy respectively and apoptosis was measured by flowcytometry with time difference as 4h, 24h and 48h after irradiation. Morphometric analysis by percent nucleus was measured in three cell groups, also. Results: Lymphocytes showed radiation sensitivity by increasing apoptotic fraction according to radiation dose. However, both mature and immature dendritic cells showed consistent fraction of apoptosis in spite of increasing radiation dose. Percent nucleus ratio is significantly higher in lymphocytes than that of mature or immature dendritic cells. Stimulation of T-cell by dendritic cells was not changed after irradiation. Conclusion: Dendritic cells showed radioresistance which was associated with small size of nucleus in comparison with lymphocytes and this result would be used as a basal data of radio-labelling for the cellular trafficking studios in nuclear medicine fields.

• Radiation Oncology Journal
• /
• v.5 no.2
• /
• pp.83-95
• /
• 1987

The synergistic effect of combining radiation therapy and hyperthermia kills significantly more cells than using either modality alone. The reason for enhanced cell killing from the combined treatment is that the two modalities are complementary. For histopathological exmination, 102 rats were divided into 4 groups as hyperthermia, radiation, hyperthermia combined with radiation and normal control groups. The effect of prior irradiation (6-15 Gy of X-ray) on the response of small and large bowel of rats to $40^{\circ}C-44^{\circ}C$ (for 30 minutes) microwave (2450 MHz) hyperthermia was investigated. The musculature of the small and large intestine remained intact and the circumference of the histological sections were not significantly altered by the heated at $43^{\circ}C$ for 30 minutes. Thermal enhancement ratios of normal tissue is 1.0 Thermal enhancement ratio was not increased in combination therapy by evaluation of histopathologic changes in small and large intestine.

• Journal of radiological science and technology
• /
• v.27 no.2
• /
• pp.45-50
• /
• 2004

Synthesis diamond films have been deposited on the molybdenum substrates using an microwave plasma enhanced chemical vapor deposition method. The effects of deposition time, surface morphology, infrared transmittance and Raman scattering have been studied. Diamond deposited on molybdenum substrate for 100 hours by MW plasma CVD from $CH_4-H_2-O_2$ gas mixture had good crystallity with $100[{\mu}m]$ thickness needed for radiation detector. Diamond radiation detector of M-I-M type was made and the current of radiation detector was increased by increasing X-ray dose.

• Korean Journal of Environmental Biology
• /
• v.34 no.4
• /
• pp.304-313
• /
• 2016

One of the issues currently facing nuclear power plants is how to store spent nuclear waste materials which are contaminated with radionuclides such as $^{134}Cs$, $^{135}Cs$, and $^{137}Cs$. Bioremediation processes may offer a potent method of cleaning up radioactive cesium. However, there have only been limited reports on $Cs^+$ tolerant bacteria. In this study, we report the isolation and identification of $Cs^+$ tolerant bacteria in environmental soil and sediment. The resistant $Cs^+$ isolates were screened from enrichment cultures in R2A medium supplemented with 100 mM CsCl for 72 h, followed by microbial community analysis based on sequencing analysis from 16S rRNA gene clone libraries(NCBI's BlastN). The dominant Bacillus anthracis Roh-1 and B. cereus Roh-2 were successfully isolated from the cesium enrichment culture. Importantly, B. cereus Roh-2 is resistant to 30% more $Cs^+$ than is B. anthracis Roh-1 when treated with 50 mM CsCl. Growth experiments clearly demonstrated that the isolate had a higher tolerance to $Cs^+$. In addition, we investigated the adsorption of $0.2mg\;L^{-1}$ $Cs^+$ using B. anthracis Roh-1. The maximum $Cs^+$ biosorption capacity of B. anthracis Roh-1 was $2.01mg\;g^{-1}$ at pH 10. Thus, we show that $Cs^+$ tolerant bacterial isolates could be used for bioremediation of contaminated environments.

• Journal of the Korea Concrete Institute
• /
• v.26 no.4
• /
• pp.517-524
• /
• 2014

Nitrite-Type hydrocalumite (calumite) is a material that can adsorb chloride ions ($Cl^-$) that cause corrosion of reinforce bars and liberate the nitrite ions ($NO_2{^-}$) that inhibit corrosion in reinforced concrete. In this study, polymer-modified mortars using two types of epoxy resin with calumite are prepared with various polymer binder-ratios of 0, 5, 10, 15, 20% and calumite contents of 0, 5%. The specimens are tested for chloride ion penetration, carbonation, drying shrinkage and corrosion inhibition. As a result, the chloride ion penetration and carbonation depth of PMM using epoxy resin somewhat increases with increasing calumite contents, but those remarkably decreases depending on the polymer-binder ratios. The 28-d drying shrinkage shows a tendency to decrease with increasing polymer-binder ratio and calumite content. Unmodified mortars with calumite content of 5% did not satisfy quality requirement by KS. However, it was satisfied with KS requirement by the modification of epoxy resin in cement mortar. On the whole, the carbonation and chloride ion penetration depth of epoxy-modified mortars with calumite is considerably improved with an increase in the polymer-binder ratio regardless of the calumite content, and is remarkably improved over unmodified mortar. And, the replacement of the portland cement with the calumite has a marked effect in the corrosion-inhibiting property of the epoxy-modified mortars.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2002.09a
• /
• pp.139-162
• /
• 2002

Since weak zones or geological lineaments are likely to be eroded, weak zones may develop beneath rivers, and a careful evaluation of ground condition is important to construct structures passing through a river. Dc resistivity surveys, however, have seldomly applied to the investigation of water-covered area, possibly because of difficulties in data aquisition and interpretation. The data aquisition having high quality may be the most important factor, and is more difficult than that in land survey, due to the water layer overlying the underground structure to be imaged. Through the numerical modeling and the analysis of case histories, we studied the method of resistivity survey at the water-covered area, starting from the characteristics of measured data, via data acquisition method, to the interpretation method. We unfolded our discussion according to the installed locations of electrodes, ie., floating them on the water surface, and installing at the water bottom, since the methods of data acquisition and interpretation vary depending on the electrode location. Through this study, we could confirm that the dc resistivity method can provide the fairly reasonable subsurface images. It was also shown that installing electrodes at the water bottom can give the subsurface image with much higher resolution than floating them on the water surface. Since the data acquired at the water-covered area have much lower sensitivity to the underground structure than those at the land, and can be contaminated by the higher noise, such as streaming potential, it would be very important to select the acquisition method and electrode array being able to provide the higher signal-to-noise ratio data as well as the high resolving power. The method installing electrodes at the water bottom is suitable to the detailed survey because of much higher resolving power, whereas the method floating them, especially streamer dc resistivity survey, is to the reconnaissance survey owing of very high speed of field work.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2001.05a
• /
• pp.258-259
• /
• 2001

• Membrane Journal
• /
• v.17 no.4
• /
• pp.338-344
• /
• 2007

Electro-electrodialysis of hydriodic acid with HI molality of ca. 9.5 $mol/kg-H_2O$ was examined in the presence of iodine using a commercial cation exchange membrane, CMB, as a separator. For the increase of the selectivity of proton permeation, the membrane was radiation-treated by accelerated electron radiation. The membrane properties (area resistance, ion exchange capacity, water content) of the radiation-treated membranes were measured. The area resistance in 2 $mol/dm^3$ KCl solution, ion exchange capacity and water content of the radiation-treated membranes at each dose rate dad almost the same value as that of the non-treated membrane (original of CMB membrane). Electro-electrodialysis of hydriodic acid with HI molality of ca. 9.5 $mol/kg-H_2O$ was examined at $75^{\circ}C$ with 9.6 $A/dm^2$. The radiation-treated cation exchange membrane by accelerated electron radiation had higher selectivity of the proton permeation by cross-linking structure of polymer than that of the non-treated membrane.