• Nuclear Engineering and Technology
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• v.50 no.8
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• pp.1298-1305
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• 2018

The use of System-on-Chip (SoC) solutions in the design of on-board data handling systems is an important step towards further miniaturization in space. However, the Total Ionizing Dose (TID) and Single Event Effects (SEE) characterization of these complex devices present new challenges that are either not fully addressed by current testing guidelines or may result in expensive, cumbersome test configurations. In this paper we report the test setups, procedures and results for TID testing of a SoC microcontroller both using standard $^{60}Co$ and low-energy protons beams. This paper specifically points out the differences in the test methodology and in the challenges between TID testing with proton beam and with the conventional gamma ray irradiation. New test setup and procedures are proposed which are capable of emulating typical mission conditions (clock, bias, software, reprogramming, etc.) while keeping the test setup as simple as possible at the same time.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.5
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• pp.657-663
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• 2015

Ionizing radiation induces cell damage through formation of reactive oxygen species. The present study was designed to evaluate the protective effects of post-treatment with hesperetin against ${\gamma}$-irradiation-induced cellular damage and oxidative stress in BALB/c mice. Healthy female BALB/c mice were exposed to ${\gamma}$-irradiation and administered hesperetin (25 mg/kg and 50 mg/kg, b.w., orally) for 7 days after 6 Gy of ${\gamma}$-irradiation. Exposure to ${\gamma}$-irradiation resulted in hematopoietic system damage manifested as decreases in spleen indexes and WBC count. In addition, hepatocellular damage characterized by increased levels of aspartate aminoransferase (AST) and alanine aminotransferase (ALT) in plasma. However, post-irradiation treatment with hesperetin provided significant protection against hematopoietic system damage and decreased AST and ALT levels in plasma. The results indicate that ${\gamma}$-irradiation induced increases in lipid peroxidation and xanthine oxidase (XO) as well as decreases in antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase) and glutathione (GSH) in the liver. These effects were also attenuated by post-treatment with hesperetin, which decreased lipid peroxidation and XO as well as increased antioxidant enzymes and GSH. These results show that post-treatment with hesperetin offers protection against ${\gamma}$-irradiation-induced tissue damage and oxidative stress and can be developed as an effective radioprotector during radiotherapy.

• Radiation Oncology Journal
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• v.19 no.2
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• pp.171-180
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• 2001

Purpose : Expression of TIMP, intrinsic inhibitor of MMP, is regulated by signal transduction in response to genotoxins and is likely to be an important step in metastasis, angiogenesis and wound healing after ionizing radiation. Therefore, we studied radiation mediated TIMP expression and its mechanism in head and neck cancer cell lines. Materials and Methods : Human head and neck cancer cell lines established at Asan Medical Center were used and radiosensitivity $(D_0)$, radiation cytotoxicity and metastatic potential were measured by clonogenic assay, n assay and invasion assay, respectively. The conditioned medium was prepared at 24 hours and 48 hours after 2 Gy and 10 Gy irradiation and expression of TIMP protein was measured by Elisa assay with specific antibodies against human TIMP. hTIMP1 promoter region was cloned and TIMP1 luciferase reporter vector was constructed. The reporter vector was transfected to AMC-HN-1 and -HN-9 cells with or without expression vector Ras, then the cells were exposed to radiation or PMA, PKC activator. EMSA was peformed with oligonucleotide (-59/-53 element and SP1) of TIMP1 promoter. Results : $D_0$ of HN-1, -2, -3, -5 and -9 cell lines were 1.55 Gy, 1.8 Gy, 1.5 Gt, 1.55 Gy and 2.45 Gy respectively. n assay confirmed cell viability, over $94\%$ at 24hrs, 48hrs after 2 Gy irradiation and over 73% after 10 Gy irradiation. Elisa assay confirmed that cells secreted TIMP1, 2 proteins continuously. After 2 Gy irradiation, TIMP2 secretion was decreased at 24hrs in HN-1 and HN-9 cell lines but after 10 Gy irradiation, it was increased in all cell lines. At 48hrs after irradiation, it was increased in HN-1 but decreased in HN-9 cells. But the change in TIMP secretion by RT was mild. The transcription of TIMP1 gene in HN-1 was induced by PMA but in HN-9 cell lines, it was suppressed. Wild type Ras induced the TIMP-1 transcription by 20 fold and 4 fold in HN-1 and HN-9 respectively. The binding activity to -59/-53, AP1 motif was increased by RT, but not to SP1 motif in both cell lines. Conclusions : We observed the difference of expression and activity of TIMPs between radiosensitive and radioresistant cell line and the different signal transduction pathway between in these cell lines may contribute the different radiosensitivity. Further research to investigate the radiation response and its signal pathway of TIMPs is needed.

• The Korean Journal of Zoology
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• v.7 no.2
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• pp.6-12
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• 1964

The present paper deals with the changes in serum protein fraction, total serum protein, hematocrit, red blood cell, haemoglobin, and weight of liver or kidney : body weight ratio of irradiated and non-irradiated snake head, Ophicephalus argus(CANTOR) . Irrardiation doses are 2537$\AA$-7 minutes (7M) and 2537$\AA$-15 minutes (15M). Serum electrophoretic patterns showed a marked decrease in albumin fraction at 1, 3, 9, 12 and 15 days on 7M group and 15 M group. On both experimental groups percentage increases in $\alpha$1 and $\beta$ fractions occurred at different time periods in general but are interpreted as only apparent changes accompanying the greater albumin fall. ${\gamma}$-Globulin decreased at 1, 6 and 15 days on 7M group. and at 1, 3, 6 and 9 days on 15M group. Also, A/G ratio was significantly low in groups subjected to above conditions as compared to the controls. A/G ratio decreased at 3 and 15 days remarkably on both groups. On the average, the reductions in the A/G ratio were not proportional to themagnitude of ultraviolet-light. Total protein of serum changed according to suggestive changes in electrophoretic patterns of serum . Total protein of serum declined at 1, 3, 6, 9 and 12 day periods on 7M groups and at 1, 3, 9, 12 and 15 day-periods on 15 M group, and increased approaching control values at 15 and 18 day-periods on both groups. Hematocrit increased remarkably at 1, 3, 6 and 12 days and decreased at 9 and 15 days on 7M group, and increased throughout the sampling period on 15M . Red blood cell decreased throughout the sampling period and increased slightly at 6 days on 7 M group and decreased at 1, 6, 9, 15 and 18 days and increased remarkably at 3 and 12 days on 15M group. Hemoglobin decreased remarkably at 1 day-period and increased at other days on both groups. The liver weight was not remarkably changed after whole body irradiation on both groups. and kidney was increased from 1st day on 7M group and 3 rd day on 15M group respectively. It appears that changes in electropphoretic patterns of serum, A/G ratio, total protein of serum, hematocrit, red blood cell, hemoglobin, and liver or kidney weight act to the detriment of the animal following non-ionizing irradiation.

• Korean journal of applied entomology
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• v.53 no.4
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• pp.391-398
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• 2014

This study investigated inhibitory doses of electron beam and X-ray irradiation by comparing their effects on the development and reproduction of four insect pests (Myzus persicae, Tetranychus urticae, Liriomyza trifolii, and Frankliniella intonsa). When M. persicae nymphs were irradiated with 100 Gy of electron beam and 30 Gy of X-ray beam, offspring production by adults that developed from the treated nymphs was completely inhibited. When M. persicae adults were irradiated with 200 Gy of electron beam and 50 Gy of X-ray beam, emergence of the $F_1$ generation was inhibited. However, these two ionizing radiations did not affect adult longevity. When T. urticae eggs were irradiated with 150 Gy of electron beam and 50 Gy of X-ray beam, egg hatching was completely inhibited. When L. trifolii pupae were irradiated, the emergence rate decreased with increasing doses of X-ray irradiation. After F. intonsa adults were irradiated with 250 Gy of electron beam and 200 Gy of X-ray beam, egg hatching of the $F_1$ generation was completely suppressed.

• The Korean Journal of Nuclear Medicine
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• v.34 no.2
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• pp.144-153
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• 2000

Purpose: The purpose of this study was to evaluate the relationship between radiation-induced activation of DNA repair genes and radiation induced apoptosis in A431 cell line. Materials and Methods: Five and 25 Gys of gamma radiation were given to A431 cells by a Cs-137 cell irradiator. Apoptosis was evaluated by flow cytometry using annexin V-fluorescein isothiocyanate and propidium iodide staining. The expression of DNA repair genes was evaluated by both Northern and Western blot analyses. Results: The number of apoptotic cells increased with the increased radiation dose. It increased most significantly at 12 hours after irradiation. Expression of p53, p21, and hRAD50 reached the highest level at 12 hours after 5 Gy irradiation. In response to 25 Gy irradiation, hRAD50 and p21 were expressed maximally at 12 hours, but p53 and GADD45 genes showed the highest expression level after 12 hours. Conclusion: Induction of apoptosis and DNA repair by ionizing radiation were closely correlated. The peak time of inducing apoptosis and DNA repair was 12 hours in this study model. hRAD50, a recently discovered DNA repair gene, was also associated with radiation-induced apoptosis.

• Journal of Radiation Protection and Research
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• v.40 no.2
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• pp.110-117
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• 2015

Recently, Due to the increased industry using radiation inspection equipment in the semiconductor, this demand of technology research is increasing. Although semiconductor inspection equipment is using low energy X-ray from 40 keV to 120 keV, Studies of radiation damage about the low energy X-ray are lacking circumstance in our country. Therefore, It is study that BJT (bipolar junction transistor) of one type of semiconductor elements are received radiation damage by low energy X-ray. BJT were used to the NXP semiconductor company's BC817-25 (NPN type), and Used the X-ray generator for the irradiation. Radiation damage of BJT was evaluated that confirm to analyse change of collector-emitter voltage of before and after X-ray irradiation when current gain fixed to 10. X-ray generator of tube voltage was setting 40 kVp, 60 kVp, 80 kVp, 100 kVp, 120 kVp and irradiation time was setting 180s, 360s, 540s into 180s intervals. As the result, We confirmed radiation damage in BJT by low energy X-ray under 120 keV energy, and Especially the biggest radiation damage was appeared at the 80 kVp. It is expected that ELDRS (enhanced low dose rate sensitivity) phenomenon occurs on the basis of 80 kVp. This studies expect to contribute effective dose administration of semiconductor inspection equipment using low energy X-ray, Also Research and Development of X-ray filter.

• Korean Journal of Environmental Biology
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• v.20 no.2
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• pp.165-172
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• 2002

The combined action of two factors on organisms can be either antagonistic, non-effective, additive or synergistic. Although synergism is of biological importance, the common features of synergistic interaction between harmful environmental factors are largely unknown. The purpose of this study is to establish general rules describing the response of various organisms to the combined action of heat with another inactivating agent. Synergistic interaction due to the simultaneous treatment of hyperthermia with ionizing or non-ionizing radiation has been analyzed using the experimental data mainly obtained with yeast cells. In addition, the results reported by others for viruses, bacterial spores, cultured mammalian cells, plants and animals were also analyzed to check the regularities revealed. The common rules of the synergistic interaction obtained in this study can be summarized as follows. For any constant rate of exposure, the synergy can be observed only within a certain temperature range. An increase in exposure rate resulted in an increase of this specific temperature and vice versa. For a constant temperature at which the irradiation occurs, synergy can be observed within a certain dose rate range. As the exposure temperature is reduced, the optimal intensity decreases and vice versa. A new conception taken into consideration those regularities can make a clue for environmental disaster preventive analysis of the synergy of radiation with the other factor.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.1
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• pp.9-14
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• 2003

Recent studies indicated that cancer cells become resistant to ionizing radiation (IR) and chemotherapy drugs by enhanced DNA repair of the lesions. Therefore, it is expected to increase the killing of cancer cells and reduce drug resistance by inhibiting DNA repair pathways that tumor cells rely on to escape chemotherapy. There are a number of key human DNA repair pathways which depend on multimeric polypeptide activities. For example, Ku heterodimer regulatory DNA binding subunits (Ku70/Ku80) on binding to double strand DNA breaks (DSBs) are able to interact with 470-kDa DNA-dependent protein kinase catalytic subunit (DNA-PKcs), and are essential for DNA-dependent protein kinase (DNA-PK) activity. It has been known that DNA-PK is an important factor for DNA repair and also is a sensor-transmitting damage signal to downstream targets, leading to cell cycles arrest. Our ultimate goal is to develop a treatment of breast tumors by targeting proteins involved in damage-signaling pathway and/or DNA repair. This would greatly facilitate tumor cell cytotoxic activity and programmed cell death through DNA damaging drug treatment. Therefore, we designed a domain of Ku80 mutants that binds to Ku70 but not DNA end binding activity and used the peptide in co-therapy strategy to see whether the targeted inhibition of DNA-PK activity sensitized breast cancer cells to irradiation or chemotherapy drug. We observed that the synthesized peptide (HNI-38) prevented DNA-PKcs from binding to Ku70/Ku80, thus resulting in inactivation of DNA-PK activity. Consequently, the peptide treated cells exhibited poor to no DNA repair, and became highly sensitive to IR or chemotherapy drugs, and the growth of breast cancer cells was inhibited. Additionally, the results obtained in the present study also support the physiological role of resistance of cancer cells to IR or chemotherapy.

• The Journal of Korean Society for Radiation Therapy
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• v.5 no.1
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• pp.142-151
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• 1992

Radioprotective effects of a red ginseng extracts on antioxidant enzymes(Superoxide dismutase, catalase and peroxidase) activities relationship to lipid peroxidation were studied in the cytosol fraction of mice liver. The experiments were carried out on Irradiated (5.5 Gy, $^{\60}Co$) and non-irradiated ICR mice after treatment of red ginseng extracts (5.5mg/mouse ; ip), In wholebody irradiated mice, irradiation caused a decrease in the activity of all these enzymes(on Day 21) The activities of SOD, Catalase and Peroxidase of red ginseng extracts treated mice were enhanced by $35.4\%,\;20.2\%$ and $20.1\%$, compared with non-treated mice. The red ginseng extracts led to inhibited increase of malondialdehyde product by ionizing radiation. The enhanced activity of enzymes that removed free radicals generated by radiation and thereby indicate that ginseng probably plays on important role in radioprotective effect.