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Sample records for attenuation radiation damage

  1. Rosiglitazone attenuates pulmonary fibrosis and radiation-induced intestinal damage

    Energy Technology Data Exchange (ETDEWEB)

    Mangoni, M.; Gerini, C.; Sottili, M.; Cassani, S.; Stefania, G.; Biti, G. [Radiotherapy Unit, Clinical Physiopathology Department, University of Florence, Firenze (Italy); Castiglione, F. [Department of Human Pathology and Oncology, University of Florence, Firenze (Italy); Vanzi, E.; Bottoncetti, A.; Pupi, A. [Nuclear Medicine Unit, Clinical Physiopathology Department, University of Florence, Firenze (Italy)

    2011-10-15

    Full text of publication follows: Purpose.-The aim of the study was to evaluate radioprotective effect of rosiglitazone (RGZ) on a murine model of late pulmonary damage and of acute intestinal damage. Methods.- Lung fibrosis: C57 mice were treated with the radiomimetic agent bleomycin, with or without rosiglitazone (5 mg/kg/day). To obtain an independent qualitative and quantitative measure for lung fibrosis we used high resolution CT, performed twice a week during the entire observation period. Hounsfield Units (HU) of section slides from the upper and lower lung region were determined. On day 31 lungs were collected for histological analysis. Acute intestinal damage: mice underwent 12 Gy total body irradiation with or without rosiglitazone. Mice were sacrificed 24 or 72 h after total body irradiation and ileum and colon were collected. Results.- Lung fibrosis: after bleomycin treatment, mice showed typical CT features of lung fibrosis, including irregular septal thickening and patchy peripheral reticular abnormalities. Accordingly, HU lung density was dramatically increased. Rosiglitazone markedly attenuated the radiological signs of fibrosis and strongly inhibited HU lung density increase (60% inhibition at the end of the observation period). Histological analysis revealed that in bleomycin-treated mice, fibrosis involved 50-55% of pulmonary parenchyma and caused an alteration of the alveolar structures in 10% of parenchyma, while in rosiglitazone-treated mice, fibrosis involved only 20-25% of pulmonary parenchyma, without alterations of the alveolar structures. Acute intestinal damage: 24 h after 12 Gy of total body irradiation intestinal mucosa showed villi shortening, mucosal thickness and crypt necrotic changes. Rosiglitazone showed a histological improvement of tissue structure, with villi and crypts normalization and oedema reduction. Conclusion.- These results demonstrate that rosiglitazone displays a protective effect on pulmonary fibrosis and radiation

  2. Rosiglitazone attenuates pulmonary fibrosis and radiation-induced intestinal damage

    International Nuclear Information System (INIS)

    Full text of publication follows: Purpose.-The aim of the study was to evaluate radioprotective effect of rosiglitazone (RGZ) on a murine model of late pulmonary damage and of acute intestinal damage. Methods.- Lung fibrosis: C57 mice were treated with the radiomimetic agent bleomycin, with or without rosiglitazone (5 mg/kg/day). To obtain an independent qualitative and quantitative measure for lung fibrosis we used high resolution CT, performed twice a week during the entire observation period. Hounsfield Units (HU) of section slides from the upper and lower lung region were determined. On day 31 lungs were collected for histological analysis. Acute intestinal damage: mice underwent 12 Gy total body irradiation with or without rosiglitazone. Mice were sacrificed 24 or 72 h after total body irradiation and ileum and colon were collected. Results.- Lung fibrosis: after bleomycin treatment, mice showed typical CT features of lung fibrosis, including irregular septal thickening and patchy peripheral reticular abnormalities. Accordingly, HU lung density was dramatically increased. Rosiglitazone markedly attenuated the radiological signs of fibrosis and strongly inhibited HU lung density increase (60% inhibition at the end of the observation period). Histological analysis revealed that in bleomycin-treated mice, fibrosis involved 50-55% of pulmonary parenchyma and caused an alteration of the alveolar structures in 10% of parenchyma, while in rosiglitazone-treated mice, fibrosis involved only 20-25% of pulmonary parenchyma, without alterations of the alveolar structures. Acute intestinal damage: 24 h after 12 Gy of total body irradiation intestinal mucosa showed villi shortening, mucosal thickness and crypt necrotic changes. Rosiglitazone showed a histological improvement of tissue structure, with villi and crypts normalization and oedema reduction. Conclusion.- These results demonstrate that rosiglitazone displays a protective effect on pulmonary fibrosis and radiation

  3. Simvastatin attenuates radiation-induced tissue damage in mice

    International Nuclear Information System (INIS)

    The aim of this study was to investigate the protective effect of simvastatin against radiation-induced tissue injury in mice. Mice were radiated with 4 Gy or 8 Gy after 20 mg/kg/d simvastatin treatment over 2 weeks. Morphological changes were observed in the jejunum and bone marrow, and apoptotic cells were determined in both tissues. Peripheral blood cells were counted, and the superoxide dismutase (SOD) activity and the malondialdehyde (MDA) level in tissues of both thymus and spleen were measured. Compared with the radiation-only group, 20 mg/kg/d simvastatin administration significantly increased the mean villi height and decreased apoptotic cells in jejunum tissue, and stimulated regeneration and reduced apoptotic cells in bone marrow. Peripheral blood cell analysis revealed that simvastatin treatment induced a larger number of red blood cells and increased the hemoglobin level present after 4 Gy of radiation. Interestingly, it was also found that the number of peripheral endothelial progenitor cells was markedly increased following simvastatin administration. Antioxidant determination for tissues displayed that simvastatin therapy increased the SOD activity after both 4 and 8 Gy of radiation, but only decreased the MDA level after 4 Gy. Simvastatin ameliorated radiation-induced tissue damage in mice. The radioprotective effect of simvastatin was possibly related to inhibition of apoptosis and improvement of oxygen-carrying and antioxidant activities. (author)

  4. Curcumin Attenuates Gamma Radiation Induced Intestinal Damage in Rats

    International Nuclear Information System (INIS)

    Small Intestine exhibits numerous morphological and functional alterations during radiation exposure. Oxidative stress, a factor implicated in the intestinal injury may contribute towards some of these alterations. The present work was designed to evaluate the efficacy of curcumin, a yellow pigment of turmeric on y-radiation-induced oxidative damage in the small intestine by measuring alterations in the level of thiobarbituric acid reactive substances (TSARS), serotonin metabolism, catecholamine levels, and monoamine oxidase (MAO) activity in parallel to changes in the architecture of intestinal tissues. In addition, monoamine level, MAO activity and TSARS level were determined in the serum. Curcumin was supplemented orally via gavages, to rats at a dose of (45 mg/ Kg body wt/ day) for 2 weeks pre-irradiation and the last supplementation was 30 min pre exposure to 6.5 Gy gamma radiations (applied as one shot dose). Animals were sacrificed on the 7th day after irradiation. The results demonstrated that, whole body exposure of rats to ionizing radiation has induced oxidative damage in small intestine obvious by significant increases of TSARS content, MAO activity and 5-hydroxy indole acetic acid (5-HIAA) and by significant decreases of serotonin (5-HT), dopamine (DA), norepinephrine (NE) and epinephrine (EPI) levels. In parallel histopathological studies of the small intestine of irradiated rats through light microscopic showed significant decrease in the number of villi, villus height, mixed sub mucosa layer with more fibres and fibroblasts. Intestinal damage was in parallel to significant alterations of serum MAO activity, TBARS, 5-HT, DA, NE and EPI levels. Administration of curcumin before irradiation has significantly improved the levels of monoamines in small intestine and serum of irradiated rats, which was associated with significant amelioration in MAO activity and TBARS contents

  5. Wheat Germ Oil Attenuates Gamma Radiation- Induced Skeletal Muscles Damage in Rats

    International Nuclear Information System (INIS)

    Muscular strength is important in sport as well as in daily activities. Exposure to ionizing radiation is thought to increase oxidative stress and damage muscle tissue. Wheat germ oil is a natural unrefined vegetable oil. It is an excellent source of vitamin E, octacosanol, linoleic and linolenic essential fatty acids, which may be beneficial in neutralizing the free oxygen radicals. The present study was designed to investigate the efficacy of wheat germ oil, on radiation-induced oxidative damage in rats skeletal muscle. Wheat germ oil was supplemented orally via gavages to rats at a dose of 54 mg/ kg body weight/day for 14 successive days pre- and 7 post-exposure to 5 Gy (one shot dose) of whole body gamma irradiation. Animals were sacrificed 7, 14 and 21 days post radiation exposure. The results revealed that whole body gamma-irradiation of rats induces oxidative stress in skeletal muscles obvious by significant elevation in the level of thiobarbituric acid reactive substances (TBARS) associated with significant decreases in the content of reduced glutathione (GSE1), as well as decreases in superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities. Irradiated rats showed, also, significant decreases in creatine phosphokinase (CPK), glutamate dehydrogenase (GDH) and glucose-6-phosphate dehydrogenase (G-6-PD) activities. Furthermore, total iron, total copper and total calcium levels were significantly increased in skeletal muscles of irradiated rats group compared to control group. Wheat germ oil treated-irradiated rats showed significantly less sever damage and remarkable improvement in all the measured parameters, compared to irradiated rats. It could be concluded that wheat germ oil by attenuating radiation induced oxidative stress might play a role in maintaining skeletal muscle integrity

  6. Administration of ON 01210.Na after exposure to ionizing radiation protects bone marrow cells by attenuating DNA damage response

    International Nuclear Information System (INIS)

    Ionizing radiation-induced hematopoietic injury could occur either due to accidental exposure or due to diagnostic and therapeutic interventions. Currently there is no approved drug to mitigate radiation toxicity in hematopoietic cells. This study investigates the potential of ON 01210.Na, a chlorobenzylsulfone derivative, in ameliorating radiation-induced hematopoietic toxicity when administered after exposure to radiation. We also investigate the molecular mechanisms underlying this activity. Male C3H/HeN mice (n = 5 mice per group; 6-8 weeks old) were exposed to a sub-lethal dose (5 Gy) of γ radiation using a 137Cs source at a dose rate of 0.77 Gy/min. Two doses of ON 01210.Na (500 mg/kg body weight) were administered subcutaneously at 24 h and 36 h after radiation exposure. Mitigation of hematopoietic toxicity by ON 01210.Na was investigated by peripheral white blood cell (WBC) and platelet counts at 3, 7, 21, and 28 d after radiation exposure. Granulocyte macrophage colony forming unit (GM-CFU) assay was done using isolated bone marrow cells, and terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) was performed on bone marrow sections at 7 d post-exposure. The DNA damage response pathway involving ataxia telangiectasia mutated (ATM) and p53 was investigated by Western blot in bone marrow cells at 7 d post-exposure. Compared to the vehicle, ON 01210.Na treated mice showed accelerated recovery of peripheral WBC and platelet counts. Post-irradiation treatment of mice with ON 01210.Na also resulted in higher GM-CFU counts. The mitigation effects were accompanied by attenuation of ATM-p53-dependent DNA damage response in the bone marrow cells of ON 01210.Na treated mice. Both phospho-ATM and phospho-p53 were significantly lower in the bone marrow cells of ON 01210.Na treated than in vehicle treated mice. Furthermore, the Bcl2:Bax ratio was higher in the drug treated mice than the vehicle treated groups. ON 01210.Na treatment significantly

  7. Attenuation of radiation-induced DNA damage due to paracrine interactions between normal human epithelial and stromal cells

    International Nuclear Information System (INIS)

    Complete text of publication follows. Objective: Developmentally, every tissue accommodates different types of cells, such as epitheliocytes and stromal cells in parenchymal organs. To better understand the complexity of radiation response, it is necessary to evaluate possible cross-talk between different tissue components. This work was set out to investigate reciprocal influence of normal human epithelial cells and fibroblasts on the extent of radiation-induced DNA damage. Methods: Model cultures of primary human thyrocytes (PT), normal diploid fibroblasts (BJ), PT/BJ cell co-culture and conditioned medium transfer were used to examine DNA damage in terms of γ-H2AX foci number per cell or by Comet assay after exposure to different doses of γ-rays. Results: In co-cultures, the kinetics of γ-H2AX foci number change was dose-dependent and similar to that in individual PT and BJ cultures. The number of γ-H2AX foci in co-cultures was significantly lower (∼25%) in both types of cells comparing to individual cultures. Reciprocal conditioned medium transfer to individual counterpart cells prior to irradiation resulted in approximately 35% reduction in the number γ-H2AX foci at 1 Gy and lower doses in both PT and BJ demonstrating the role of paracrine soluble factors. Comet assay corroborated the results of γ-H2AX foci counting in conditioned medium transfer experiments. In contrast to medium conditioned on PT cells, conditioned medium collected from several human thyroid cancer cell lines failed to establish DNA-protected state in BJ fibroblasts. In its turn, medium conditioned on BJ cells did not change the extent of radiation-induced DNA damage in cancer cell lines tested. Conclusion: The results imply the existence of a network of soluble factor-mediated paracrine interactions between normal epithelial and stromal cells that could be a part of natural mechanism by which cells protect DNA from genotoxic stress.

  8. Multiple low-dose radiation prevents type 2 diabetes-induced renal damage through attenuation of dyslipidemia and insulin resistance and subsequent renal inflammation and oxidative stress.

    Directory of Open Access Journals (Sweden)

    Minglong Shao

    Full Text Available BACKGROUND: Dyslipidemia and lipotoxicity-induced insulin resistance, inflammation and oxidative stress are the key pathogeneses of renal damage in type 2 diabetes. Increasing evidence shows that whole-body low dose radiation (LDR plays a critical role in attenuating insulin resistance, inflammation and oxidative stress. OBJECTIVE: The aims of the present study were to investigate whether LDR can prevent type 2 diabetes-induced renal damage and the underlying mechanisms. METHODS: Mice were fed with a high-fat diet (HFD, 40% of calories from fat for 12 weeks to induce obesity followed by a single intraperitoneal injection of streptozotocin (STZ, 50 mg/kg to develop a type 2 diabetic mouse model. The mice were exposed to LDR at different doses (25, 50 and 75 mGy for 4 or 8 weeks along with HFD treatment. At each time-point, the kidney weight, renal function, blood glucose level and insulin resistance were examined. The pathological changes, renal lipid profiles, inflammation, oxidative stress and fibrosis were also measured. RESULTS: HFD/STZ-induced type 2 diabetic mice exhibited severe pathological changes in the kidney and renal dysfunction. Exposure of the mice to LDR for 4 weeks, especially at 50 and 75 mGy, significantly improved lipid profiles, insulin sensitivity and protein kinase B activation, meanwhile, attenuated inflammation and oxidative stress in the diabetic kidney. The LDR-induced anti-oxidative effect was associated with up-regulation of renal nuclear factor E2-related factor-2 (Nrf-2 expression and function. However, the above beneficial effects were weakened once LDR treatment was extended to 8 weeks. CONCLUSION: These results suggest that LDR exposure significantly prevented type 2 diabetes-induced kidney injury characterized by renal dysfunction and pathological changes. The protective mechanisms of LDR are complicated but may be mainly attributed to the attenuation of dyslipidemia and the subsequent lipotoxicity

  9. Radiation Damage Workshop

    Science.gov (United States)

    Stella, P. M.

    1984-01-01

    The availability of data regarding the radiation behavior of GaAs and silicon solar cells is discussed as well as efforts to provide sufficient information. Other materials are considered too immature for reasonable radiation evaluation. The lack of concern over the possible catastrophic radiation degradation in cascade cells is a potentially serious problem. Lithium counterdoping shows potential for removing damage in irradiated P-type material, although initial efficiencies are not comparable to current state of the art. The possibility of refining the lithium doping method to maintain high initial efficiencies and combining it with radiation tolerant structures such as thin BSF cells or vertical junction cells could provide a substantial improvement in EOL efficiencies. Laser annealing of junctions, either those formed ion implantation or diffusion, may not only improve initial cell performance but might also reduce the radiation degradation rate.

  10. Radiation damage effects

    International Nuclear Information System (INIS)

    The summarized data suggest that both glass and crystalline waste forms may sustain substantial doses of α-decay damage and still retain their durability. Radiation effects in glasses are less pronounced and less complicated than that in single or poly-phase ceramics; thus, the latter category requires careful research and consideration. Perhaps the most important conclusion is that short-term actinide doping experiments in crystalline phases provide a realistic simulation of long-term effects based on the comparison of observed radiation effects in Pu-doped zircon and naturally damaged zircon (there is a 107 difference in dose rate). Deviations from the similarity in effect (e.g., saturation dose) may be attributed to low-temperature, long-term annealing effects

  11. Radiation damage tolerant nanomaterials

    Directory of Open Access Journals (Sweden)

    I.J. Beyerlein

    2013-11-01

    Full Text Available Designing a material from the atomic level to achieve a tailored response in extreme conditions is a grand challenge in materials research. Nanostructured metals and composites provide a path to this goal because they contain interfaces that attract, absorb and annihilate point and line defects. These interfaces recover and control defects produced in materials subjected to extremes of displacement damage, impurity implantation, stress and temperature. Controlling radiation-induced-defects via interfaces is shown to be the key factor in reducing the damage and imparting stability in certain nanomaterials under conditions where bulk materials exhibit void swelling and/or embrittlement. We review the recovery of radiation-induced point defects at free surfaces and grain boundaries and stabilization of helium bubbles at interphase boundaries and present an approach for processing bulk nanocomposites containing interfaces that are stable under irradiation.

  12. Radiation damage of uranium

    International Nuclear Information System (INIS)

    Study of radiation damage covered the following: Kinetics of electric resistance of uranium and uranium alloy with 1% of molybdenum dependent on the second phase and burnup rate; Study of gas precipitation and diffusion of bubbles by transmission electron microscopy; Numerical analysis of the influence of defects distribution and concentration on the rare gas precipitation in uranium; study of thermal sedimentation of uranium alloy with molybdenum; diffusion of rare gas in metal by gas chromatography method

  13. Radiation damage in graphite

    CERN Document Server

    Simmons, John Harry Walrond

    1965-01-01

    Nuclear Energy, Volume 102: Radiation Damage in Graphite provides a general account of the effects of irradiation on graphite. This book presents valuable work on the structure of the defects produced in graphite crystals by irradiation. Organized into eight chapters, this volume begins with an overview of the description of the methods of manufacturing graphite and of its physical properties. This text then presents details of the method of setting up a scale of irradiation dose. Other chapters consider the effect of irradiation at a given temperature on a physical property of graphite. This

  14. Attenuation of the DNA Damage Response by Transforming Growth Factor-Beta Inhibitors Enhances Radiation Sensitivity of Non–Small-Cell Lung Cancer Cells In Vitro and In Vivo

    Energy Technology Data Exchange (ETDEWEB)

    Du, Shisuo; Bouquet, Sophie; Lo, Chen-Hao; Pellicciotta, Ilenia; Bolourchi, Shiva [Department of Radiation Oncology, New York University School of Medicine, New York, New York (United States); Parry, Renate [Varian Medical Systems, Palo Alto, California (United States); Barcellos-Hoff, Mary Helen, E-mail: mhbarcellos-hoff@nyumc.org [Department of Radiation Oncology, New York University School of Medicine, New York, New York (United States)

    2015-01-01

    Purpose: To determine whether transforming growth factor (TGF)-β inhibition increases the response to radiation therapy in human and mouse non–small-cell lung carcinoma (NSCLC) cells in vitro and in vivo. Methods and Materials: TGF-β–mediated growth response and pathway activation were examined in human NSCLC NCI-H1299, NCI-H292, and A549 cell lines and murine Lewis lung cancer (LLC) cells. Cells were treated in vitro with LY364947, a small-molecule inhibitor of the TGF-β type 1 receptor kinase, or with the pan-isoform TGF-β neutralizing monoclonal antibody 1D11 before radiation exposure. The DNA damage response was assessed by ataxia telangiectasia mutated (ATM) or Trp53 protein phosphorylation, γH2AX foci formation, or comet assay in irradiated cells. Radiation sensitivity was determined by clonogenic assay. Mice bearing syngeneic subcutaneous LLC tumors were treated with 5 fractions of 6 Gy and/or neutralizing or control antibody. Results: The NCI-H1299, A549, and LLC NSCLC cell lines pretreated with LY364947 before radiation exposure exhibited compromised DNA damage response, indicated by decreased ATM and p53 phosphorylation, reduced γH2AX foci, and increased radiosensitivity. The NCI-H292 cells were unresponsive. Transforming growth factor-β signaling inhibition in irradiated LLC cells resulted in unresolved DNA damage. Subcutaneous LLC tumors in mice treated with TGF-β neutralizing antibody exhibited fewer γH2AX foci after irradiation and significantly greater tumor growth delay in combination with fractionated radiation. Conclusions: Inhibition of TGF-β before radiation attenuated DNA damage recognition and increased radiosensitivity in most NSCLC cells in vitro and promoted radiation-induced tumor control in vivo. These data support the rationale for concurrent TGF-β inhibition and RT to provide therapeutic benefit in NSCLC.

  15. Radiation-attenuated vaccine for lungworm disease

    International Nuclear Information System (INIS)

    The work done at the Indian Veternary Research Institute, Izatnagar, on the development of a vaccine for lungworm diseases is reported. Research work done includes: (1) studies on the epidemiology and the incidence of the lungworm infections, (ii) studies on the radiation-attenuated lungworm Dictyocaulus filaria vaccine, (iii) studies on other parasites using ionizing radiation, (iv) incidence of lungworm infection in sheep in Jammu and Kashmir State, (v) suitable dose of gamma radiation for attenuation, (vi) laboratory studies with radiation-attenuated D. filaria vaccine, (vii) serology of D. filaria infection, (viii) field trials with the radiation-attenuated vaccine, (ix) immune response of previously exposed lambs to vaccination, (x) comparative susceptibility of sheep and goats to infection with D. filaria, (xi) quantitative studies of D. filaria in lambs and (xii) production and supply of lungworm vaccine. (A.K.)

  16. Radiation damage in biomolecular systems

    CERN Document Server

    Fuss, Martina Christina

    2012-01-01

    Since the discovery of X-rays and radioactivity, ionizing radiations have been widely applied in medicine both for diagnostic and therapeutic purposes. The risks associated with radiation exposure and handling led to the parallel development of the field of radiation protection. Pioneering experiments done by Sanche and co-workers in 2000 showed that low-energy secondary electrons, which are abundantly generated along radiation tracks, are primarily responsible for radiation damage through successive interactions with the molecular constituents of the medium. Apart from ionizing processes, which are usually related to radiation damage, below the ionization level low-energy electrons can induce molecular fragmentation via dissociative processes such as internal excitation and electron attachment. This prompted collaborative projects between different research groups from European countries together with other specialists from Canada,  the USA and Australia. This book summarizes the advances achieved by these...

  17. Radiation Damage and Dimensional Changes

    International Nuclear Information System (INIS)

    The dimensional changes have been modeled in order to be accommodated in the reactor design. This study has major implications for the interpretation of damage in carbon based nuclear fission and fusion plant materials. Radiation damage of graphite leads to self-interstitials and vacancies defects. The aggregation of these defects causes dimensional changes. Vacancies aggregate into lines and disks which heal and contract the basal planes. Interstitials aggregate into interlayer disks which expand the dimension

  18. Radiation damage of germanium detectors

    Science.gov (United States)

    Pehl, R. H.

    1978-01-01

    Energetic particles can produce interstitial-vacancy pairs in a crystal by knocking the atoms from their normal positions. Detectors are unique among semiconductor devices in depending on very low concentrations of electrically active impurities, and also on efficient transport of holes and electrons over relatively large distances. Because the dense regions of damage produced by energetic particles may result in donors and/or acceptors, and also provide trapping sites for holes and electrons, detectors are very sensitive to radiation damage. In addition to these effects occurring within the detector, radiation may also change the characteristics of the exposed surfaces causing unpredictable effects on the detector leakage current. Radiation-induced surface degradation has rarely, if ever, been observed for germanium detectors. The possibility of minimizing hole trapping in charge collection by the use of a high-purity germanium coaxial detector configured with the p (+) contact on the coaxial periphery is discussed.

  19. Photon attenuation characteristics of radiation shielding materials

    International Nuclear Information System (INIS)

    In the design and construction of installation housing high intensity radiation sources and other radiation generating equipment, a variety of shielding materials are used to minimise exposure to individual. Among the materials, lead is best known for radiation shielding characteristics due to their high density and atomic number. Commercial and barium enriched cement, apart from better compressive strength, smoother surface finish and high abrasion resistance, offers adequate shielding to gamma radiations. Although photon attenuation data are available in literature, it is necessary to test these commercially available material experimentally for their radiation shielding efficiency before putting them in to regular use. In the present work, attenuation characteristics of lead. commercial cement and barium enriched cement supplied by a manufacturing firm have been studied for photons of 662 and 1250keV from Cs-137 and Co-60. The radiographic sources of Cs-137 and Co-60 of radioactive strength of 260 and 30 mCi respectively were utilised in the present investigation. Experimental measurements were done with gamma radiography survey meter MR 4500A placed at a distance of 2 meters from the source. Attenuation coefficients for photons in commercial cement, barite and lead were determined experimentally through photon transmission measurements performed under broad beam counting geometry. The absorbers used were in form of thin sheets of lead, commercial cements and barite of uniform thicknesses. These thin sheets were weighed accurately on an analytical balance and from their measured area, thicknesses proportional to area density in gram.cm-2 were determined. The average thickness of each absorber varied from a few milligram to several gram per cm-2. Higher thicknesses were obtained by stacking the absorbers with each other. Each absorber of specified thickness was interposed between the source and detector such that the primary beam is incident normally on its

  20. Using ultrasonic attenuation for assessing the fatigue damage of concrete

    International Nuclear Information System (INIS)

    The results from cyclic loading tests indicate that damage accumulation as measured by pulse attenuation during cyclic loading is not linear, particularly during the initial cycles. The crack growth results obtained may be used for ascertaining the extent of damage in a in-situ structure using the following procedure: The ultrasonic waveforms obtained from a damaged region can first be compared with that obtained from the same region initially to yield a damage coefficient. Then the calibration charts obtained from laboratory specimens may be used to predict the extent of damage due to cyclic loading. The proposed method can also easily be extended to predict the deterioration due to shrinkage, creep and other environmental effects as long as their effect is to produce cracking in the concrete. (orig./HP)

  1. Energy release, beam attenuation radiation damage, gas production and accumulation of long-lived activity in Pb, Pb-Bi and Hg targets

    Energy Technology Data Exchange (ETDEWEB)

    Shubin, Yu.N. [IPPE, Obninsk (Russian Federation)

    1996-06-01

    The calculation and analysis of the nuclei concentrations and long-lived residual radioactivity accumulated in Pb, Pb-Bi and Hg targets irradiated by 800 MeV, 30 mA proton beam have been performed. The dominating components to the total radioactivity of radionuclides resulting from fission and spallation reactions and radiative capture by both target nuclei and accumulated radioactive nuclei for various irradiation and cooling times were analyzed. The estimations of spectral component contributions of neutron and proton fluxes to the accumulated activity were carried out. The contributions of fission products to the targets activity and partial activities of main long-lived fission products to the targets activity and partial activities of main long-lived fission products were evaluated. The accumulation of Po isotopes due to reactions induced by secondary alpha-particles were found to be important for the Pb target as compared with two-step radiative capture. The production of Tritium in the targets and its contribution to the total targets activity was considered in detail. It is found that total activities of both targets are close to one another.

  2. Clarithromycin Attenuates Radiation-Induced Lung Injury in Mice.

    Directory of Open Access Journals (Sweden)

    Seung Jun Lee

    Full Text Available Radiation-induced lung injury (RILI is a common and unavoidable complication of thoracic radiotherapy. The current study was conducted to evaluate the ability of clarithromycin (CLA to prevent radiation-induced pneumonitis, oxidative stress, and lung fibrosis in an animal model. C57BL/6J mice were assigned to control, irradiation only, irradiation plus CLA, and CLA only groups. Test mice received single thoracic exposures to radiation and/or oral CLA (100 mg/kg/day. Histopathologic findings and markers of inflammation, fibrosis, and oxidative stress were compared by group. On a microscopic level, CLA inhibited macrophage influx, alveolar fibrosis, parenchymal collapse, consolidation, and epithelial cell changes. The concentration of collagen in lung tissue was lower in irradiation plus CLA mice. Radiation-induced expression of tumor necrosis factor (TNF-α, TNF receptor 1, acetylated nuclear factor kappa B, cyclooxygenase 2, vascular cell adhesion molecule 1, and matrix metallopeptidase 9 were also attenuated by CLA. Expression levels of nuclear factor erythroid 2-related factor 2 and heme oxygenase 1, transforming growth factor-β1, connective tissue growth factor, and type I collagen in radiation-treated lungs were also attenuated by CLA. These findings indicate that CLA ameliorates the deleterious effects of thoracic irradiation in mice by reducing pulmonary inflammation, oxidative damage, and fibrosis.

  3. Clarithromycin Attenuates Radiation-Induced Lung Injury in Mice.

    Science.gov (United States)

    Lee, Seung Jun; Yi, Chin-ok; Heo, Rok Won; Song, Dae Hyun; Cho, Yu Ji; Jeong, Yi Yeong; Kang, Ki Mun; Roh, Gu Seob; Lee, Jong Deog

    2015-01-01

    Radiation-induced lung injury (RILI) is a common and unavoidable complication of thoracic radiotherapy. The current study was conducted to evaluate the ability of clarithromycin (CLA) to prevent radiation-induced pneumonitis, oxidative stress, and lung fibrosis in an animal model. C57BL/6J mice were assigned to control, irradiation only, irradiation plus CLA, and CLA only groups. Test mice received single thoracic exposures to radiation and/or oral CLA (100 mg/kg/day). Histopathologic findings and markers of inflammation, fibrosis, and oxidative stress were compared by group. On a microscopic level, CLA inhibited macrophage influx, alveolar fibrosis, parenchymal collapse, consolidation, and epithelial cell changes. The concentration of collagen in lung tissue was lower in irradiation plus CLA mice. Radiation-induced expression of tumor necrosis factor (TNF)-α, TNF receptor 1, acetylated nuclear factor kappa B, cyclooxygenase 2, vascular cell adhesion molecule 1, and matrix metallopeptidase 9 were also attenuated by CLA. Expression levels of nuclear factor erythroid 2-related factor 2 and heme oxygenase 1, transforming growth factor-β1, connective tissue growth factor, and type I collagen in radiation-treated lungs were also attenuated by CLA. These findings indicate that CLA ameliorates the deleterious effects of thoracic irradiation in mice by reducing pulmonary inflammation, oxidative damage, and fibrosis. PMID:26114656

  4. Radiation damage in multiphase ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Men, Danju [Department of Chemical Engineering and Materials Science, University of California, Irvine, CA 92697-2575 (United States); Patel, Maulik K.; Usov, Igor O. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Toiammou, Moidi; Monnet, Isabelle [CIMAP, CEA/CNRS/ENSICAEN/Universite de Caen-Basse Normandie, Bd Henri Becquerel, BP 5133, F-14070 Caen Cedex 5 (France); Pivin, Jean Claude [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, CNRS-IN2P3-Universite Paris Sud, UMR 8609, Bat. 108, 91405 Orsay (France); Porter, John R. [Materials Department, University of California, Santa Barbara, CA 93106-5050 (United States); Mecartney, Martha L., E-mail: martham@uci.edu [Department of Chemical Engineering and Materials Science, University of California, Irvine, CA 92697-2575 (United States)

    2013-11-15

    Graphical abstract: Display Omitted -- Abstract: Four-phase ceramic composites containing 3 mol% Y{sub 2}O{sub 3} stabilized ZrO{sub 2} (3Y-TZP), Al{sub 2}O{sub 3}, MgAl{sub 2}O{sub 4}, and LaPO{sub 4} were synthesized as model materials representing inert matrix fuel with enhanced thermal conductivity and decreased radiation-induced microstructural damage with respect to single-phase UO{sub 2}. This multi-phase concept, if successful, could be applied to design advanced nuclear fuels which could then be irradiated to higher burn-ups. 3Y-TZP in the composite represents a host (fuel) phase with the lowest thermal conductivity and Al{sub 2}O{sub 3} is the high thermal conductivity phase. The role of MgAl{sub 2}O{sub 4} and LaPO{sub 4} was to stabilize the structure under irradiation. The radiation response was evaluated by ion irradiation at 500 °C with 10 MeV Au ions and at 800 °C with 92 MeV Xe ions, to simulate damage due to primary knock-on atoms and fission fragments, respectively. Radiation damage and microstructural changes were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy and computational modeling. Al{sub 2}O{sub 3}, Y{sub 2}O{sub 3} stabilized ZrO{sub 2} and MgAl{sub 2}O{sub 4} phases exhibit high amorphization resistance and remain stable when irradiated with both Au and Xe ions. A monoclinic-to-tetragonal phase transformation, however, is promoted by Xe and Au ion irradiation in 3Y-TZP. The LaPO{sub 4} monazite phase appears to melt, dewet the other phases, and recrystallize under Au irradiation, but does not change under Xe irradiation.

  5. Radiation damage of structural materials

    CERN Document Server

    Koutsky, Jaroslav

    1994-01-01

    Maintaining the integrity of nuclear power plants is critical in the prevention or control of severe accidents. This monograph deals with both basic groups of structural materials used in the design of light-water nuclear reactors, making the primary safety barriers of NPPs. Emphasis is placed on materials used in VVER-type nuclear reactors: Cr-Mo-V and Cr-Ni-Mo-V steel for RPV and Zr-Nb alloys for fuel element cladding. The book is divided into 7 main chapters, with the exception of the opening one and the chapter providing a phenomenological background for the subject of radiation damage. Ch

  6. Damages by radiation in glasses

    International Nuclear Information System (INIS)

    As a part of the works carried out to characterize the electrons beam from the Pelletron accelerator of the Mexican Nuclear Center aluminium-silicate glass samples were irradiated. The purpose of these irradiations is to cause alterations in the amorphous microstructure of the material by means of the creation of color centers. The population density of these defects, consequence to the irradiation, is function of the exposure time which varied from 1 to 30 minutes, with an electronic beam energy of 400 keV, doing the irradiations at free atmosphere. the obtained spectra are correlated by damage which the radiation produced. (Author)

  7. Attenuation of gamma radiation in concrete shields

    International Nuclear Information System (INIS)

    The attenuation characteristics of γ radiation in concrete layers considering their mechanical resistence and densities were determined. A 137Cs source was used in a 'good geometry' arrangement to eliminate the effects of the buildup factor. The ordinary and the heavy concrete were irradiated and for the latter it was used as additives iron ore and Fe2O3 pellets in various grain sizes. The detection system consisted of a 2' x 2' NaI (Tl) crystal coupled to a photomultiplier tube and the associated electronic equipment. FORTRAN programs were used for determining the absorption coefficients and the attenuation factors. These programs calculate photopeak areas eliminating all contributions due to Compton effect and background. (Author)

  8. Radiation damage to DNA constituents

    International Nuclear Information System (INIS)

    The molecular changes of the DNA molecule, in various systems exposed to inoizing radiation, have been the subject of a great number of studies. In the present work electron spin resonance spectroscopy (ESR) has been applied to irradiated crystalline systems, in particular single crystals of DNA subunits and their derivatives. The main conclusions about the molecular damage are based on this technique in combination with molecular orbital calculations. It should be emphasized that the ESR technique is restricted to damage containing unpaired electrons. These unstable intermediates called free radicals seem, however, to be involved in all molecular models describing the action of radiation on DNA. One of the premises for a detailed theory of the radiation induced reactions at the physico-chemical level seems to involve exact knowledge of the induced free radicals as well as the modes of their formation and fate. For DNA, as such, it is hardly possible to arrive at such a level of knowledge since the molecular complexity prevents selective studies of the many different radiation induced products. One possible approach is to study the free radicals formed in the constituents of DNA. In the present work three lines of approach should be mentioned. The first is based on the observation that radical formation in general causes only minor structural alterations to the molecule in question. The use of isotopes with different spin and magnetic moment (in particular deuterium) may also serve a source of information. Deuteration leads to a number of protons, mainly NH - and OH, becoming substituted, and if any of these are involved in interactions with unpaired protons the resonance pattern is influeneed. The third source of information is molecular orbital calculation. The electron spin density distribution is a function in the three dimensional space based on the system's electronic wave functions. This constitutes the basis for the idea that ESR data can be correlated with

  9. Report of board IV: Radiation damages and radiation induced diseases

    International Nuclear Information System (INIS)

    Board IV (radiation damage and radiation-induced diseases) worked on the effects of ionizing radiation on living organisms and studies the radiation damage it entailed. Investigations with cells or model systems serve to recognize certain causal relationships in an organism out of the diversity of reactions encountered. (orig./AK)

  10. Radiation damage effects in zircon

    Science.gov (United States)

    Trachenko, Kostya; Dove, Martin; Salje, Ekhard

    2002-03-01

    Zircon, ZrSiO_4, is important for geology and geochronology, and has been proposed as a host material to immobilize highly radioactive materials from dismantled weapons and nuclear waste from power stations [1]. In these applications zircon is exposed to alpha-irradiation. Computer simulations have started to be employed to simulate radiation damage in zircon [2], but the origin and microscopic mechanisms of the most important structural changes in zircon - unit cell expansion and large macroscopic swelling at higher doses, strong shear deformation of the crystalline lattice, and polymerization of SiOn units [3], remain unknown. Here, we perform the molecular dynamics simulation of highly energetic recoils in zircon. Basing on the simulation results, we propose the simple picture of the density change in the damaged region that consists of the depleted and densified matter. We find that the experimentally observed structural changes originate from the interaction of the damaged region with the surrounding crystalline lattice: the shear of the lattice around the damaged region causes shear deformation and expansion of the unit cells. The polymers of connected SiOn polyhedra are most commonly present in the densified shell at the periphery of the damaged region. [1] R C Ewing et al, J. Mater. Res. 10, 243 (1995); W J Weber et al, B E Burakov et al, in Scientific Basis for Nuclear Waste Management XIX, 25-32 and 33-40 (Plenum, New York, 1996); R C Ewing, et al in Crystalline Ceramics: Waste Forms for the Disposal of Weapons Plutonium, NATO Workshop Proceedings 65 (Academic Publishers, Dordrecht, The Netherlands, 1996). [2] B Park et al, Phys. Rev. B, 64, 174108 (1-16) (2001); J P Crocombette and D Ghaleb, J. Nucl. Mater., 295, 167 (2001); K Trachenko et al, J. Appl. Phys., 87, 7702 (2000); K Trachenko et al, J. Phys.: Cond. Matt., 13, 1947 (2001). [3] T Murakami et al, Am. Min., 76, 1510 (1991); H D Holland and D Gottfried, Acta Cryst. 8, 291 (1955).; W J Weber, J. Am

  11. Ghrelin attenuates gastrointestinal epithelial damage induced by doxorubicin

    Institute of Scientific and Technical Information of China (English)

    Mohamed A Fahim; Hazem Kataya; Rkia El-Kharrag; Dena AM Amer; Basel al-Ramadi; Sherif M Karam

    2011-01-01

    AIM: To examine the influence of ghrelin on the regenerative potential of gastrointestinal (GI) epithelium.METHODS: Damage to GI epithelium was induced in mice by two intravenous injections of doxorubicin (10 and 6 mg/kg). Some of the doxorubicin-treated mice received a continuous subcutaneous infusion of ghrelin (1.25 μg/h) for 10 d via implanted mini-osmotic pumps. To label dividing stem cells in the S-phase of the cell cycle, all mice received a single intraperitoneal injection of 5'-bromo-2'-deoxyuridine (BrdU) one hour before sacrifice. The stomach along with the duodenum were then removed and processed for histological examination and immunohistochemistry using anti-BrdU antibody. RESULTS: The results showed dramatic damage to the GI epithelium 3 d after administration of chemotherapy which began to recover by day 10. In ghrelin-treated mice, attenuation of GI mucosal damage was evident in the tissues examined post-chemotherapy. Immunohistochemical analysis showed an increase in the number of BrdU-labeled cells and an alteration in their distribution along the epithelial lining in response to damage by doxorubicin. In mice treated with both doxorubicin and ghrelin, the number of BrdU-labeled cells was reduced when compared with mice treated with doxorubicin alone. CONCLUSION: The present study suggests that ghrelin enhances the regenerative potential of the GI epithelium in doxorubicin-treated mice, at least in part, by modulating cell proliferation.

  12. Radiation damage of UO2 fuel

    International Nuclear Information System (INIS)

    Radiation damage study of fuel and fuel elements covers: study of radiation damage methods in Sweden; analysis of testing the fuel and fuel elements at the RA reactor; feasibility study of irradiation in the Institute compared to irradiation abroad in respect to the reactor possibilities. Tasks included in this study are relater to testing of irradiated UO2 and ceramic fuel elements

  13. Repair of radiation damage in mammalian cells

    International Nuclear Information System (INIS)

    The responses, such as survival, mutation, and carcinogenesis, of mammalian cells and tissues to radiation are dependent not only on the magnitude of the damage to macromolecular structures - DNA, RNA, protein, and membranes - but on the rates of macromolecular syntheses of cells relative to the half-lives of the damages. Cells possess a number of mechanisms for repairing damage to DNA. If the repair systems are rapid and error free, cells can tolerate much larger doses than if repair is slow or error prone. It is important to understand the effects of radiation and the repair of radiation damage because there exist reasonable amounts of epidemiological data that permits the construction of dose-response curves for humans. The shapes of such curves or the magnitude of the response will depend on repair. Radiation damage is emphasized because: (a) radiation dosimetry, with all its uncertainties for populations, is excellent compared to chemical dosimetry; (b) a number of cancer-prone diseases are known in which there are defects in DNA repair and radiation results in more chromosomal damage in cells from such individuals than in cells from normal individuals; (c) in some cases, specific radiation products in DNA have been correlated with biological effects, and (d) many chemical effects seem to mimic radiation effects. A further reason for emphasizing damage to DNA is the wealth of experimental evidence indicating that damages to DNA can be initiating events in carcinogenesis

  14. Seismic radiation from regions sustaining material damage

    OpenAIRE

    Ben-Zion, Yehuda; Ampuero, Jean-Paul

    2009-01-01

    We discuss analytical results for seismic radiation during rapid episodes of inelastic brittle deformation that include, in addition to the standard moment term, a damage-related term stemming from changes of elastic moduli in the source region. The radiation from the damage-related term is associated with products of the changes of elastic moduli and the total elastic strain components in the source region. Order of magnitude estimates suggest that the damage-related contribution to the moti...

  15. Radiation damage in semiconductor detectors

    Energy Technology Data Exchange (ETDEWEB)

    Kraner, H.W.

    1981-12-01

    A survey is presented of the important damage-producing interactions in semiconductor detectors and estimates of defect numbers are made for MeV protons, neutrons and electrons. Damage effects of fast neutrons in germanium gamma ray spectrometers are given in some detail. General effects in silicon detectors are discussed and damage constants and their relationship to leakage current is introduced.

  16. Radiation damage in barium fluoride detector materials

    Energy Technology Data Exchange (ETDEWEB)

    Levey, P.W.; Kierstead, J.A.; Woody, C.L.

    1988-01-01

    To develop radiation hard detectors, particularly for high energy physics studies, radiation damage is being studied in BaF/sub 2/, both undoped and doped with La, Ce, Nd, Eu, Gd and Tm. Some dopants reduce radiation damage. In La doped BaF/sub 2/ they reduce the unwanted long lifetime luminescence which interferes with the short-lived fluorescence used to detect particles. Radiation induced coloring is being studied with facilities for making optical measurements before, during and after irradiation with /sup 60/C0 gamma rays. Doses of 10/sup 6/ rad, or less, create only ionization induced charge transfer effects since lattice atom displacement damage is negligible at these doses. All crystals studied exhibit color center formation, between approximately 200 and 800 nm, during irradiation and color center decay after irradiation. Thus only measurements made during irradiation show the total absorption present in a radiation field. Both undoped and La doped BaF/sub 2/ develop damage at minimum detectable levels in the UV---which is important for particle detectors. For particle detector applications these studies must be extended to high dose irradiations with particles energetic enough to cause lattice atom displacement damage. In principle, the reduction in damage provided by dopants could apply to other applications requiring radiation damage resistant materials.

  17. DNA Damage Signals and Space Radiation Risk

    Science.gov (United States)

    Cucinotta, Francis A.

    2011-01-01

    Space radiation is comprised of high-energy and charge (HZE) nuclei and protons. The initial DNA damage from HZE nuclei is qualitatively different from X-rays or gamma rays due to the clustering of damage sites which increases their complexity. Clustering of DNA damage occurs on several scales. First there is clustering of single strand breaks (SSB), double strand breaks (DSB), and base damage within a few to several hundred base pairs (bp). A second form of damage clustering occurs on the scale of a few kbp where several DSB?s may be induced by single HZE nuclei. These forms of damage clusters do not occur at low to moderate doses of X-rays or gamma rays thus presenting new challenges to DNA repair systems. We review current knowledge of differences that occur in DNA repair pathways for different types of radiation and possible relationships to mutations, chromosomal aberrations and cancer risks.

  18. The LHCb VELO: Performance and radiation damage

    Energy Technology Data Exchange (ETDEWEB)

    Snoek, H.L., E-mail: hella.snoek@nikhef.nl

    2014-11-21

    LHCb is a forward spectrometer experiment dedicated to the search for New Physics in the decays of beauty and charm hadrons produced by the proton–proton interactions at the Large Hadron Collider (LHC) at CERN. The measurement of the flight distance of these hadrons is critical for the physics program. The VErtex LOcator (VELO) is the silicon detector surrounding the LHCb interaction point and provides excellent resolution of charged tracks and vertex positions. The VELO has been run successfully since installation. The sensors have the first sensitive strips at a radius of 8.2 mm and are exposed to maximum radiation doses of ∼0.6×10{sup 14}1MeVn{sub eq}/cm{sup 2}perfb{sup −1} delivered integrated luminosity. The performance of the VELO during the first LHC run is described, together with methods to monitor radiation damage. Results from the radiation damage studies are presented showing interesting features, such as an unexpected charge coupling to the second metal layer routing lines after irradiation. The radiation damage has so far no impact on the track reconstruction performance. - Highlights: • We study the performance and radiation damage of the LHCb VELO detector. • The physics performance of the VELO detector is meeting its expectations. • Radiation damage is monitored through multiple developed methods. • An unexpected, radiation induced effect to the second metal layer has been observed.

  19. Radiation damage of metal uranium

    International Nuclear Information System (INIS)

    This report is concerned with the role of dispersion second phase in uranium and burnup rate. The role of dispersion phases in radiation stability of metal uranium was studies by three methods: variation of electric conductivity dependent on the neutron flux and temperature of pure uranium for different states of dispersion second phase; influence of dispersion phase on the radiation creep; transmission electron microscopy of fresh and irradiated uranium

  20. New concepts for radiation damage

    International Nuclear Information System (INIS)

    Evidence accumulated over the past two decades has indicated that exposure of cell populations to ionizing radiation results in significant biological effects occurring in both the irradiated and non-irradiated cells in the population. This phenomenon, termed the 'bystander response', has been shown to occur both in vitro and in vivo. Experiments have indicated that genetic alterations, changes in gene expression and lethality occur in bystander cells that neighbour directly irradiated cells. Furthermore, cells recipient of growth medium harvested from irradiated cultures exhibit responses similar to those of the irradiated cells. Several mechanisms involving secreted soluble factors, gap-junction intercellular communication and oxidative metabolism have been proposed to regulate the radiation-induced bystander effect. In this lecture, our current knowledge of this phenomenon and its potential impact both on the estimation of risks of exposure to low doses/low fluences of ionizing radiation and on radiotherapy is discussed. (author)

  1. Radiation damage of the lens

    International Nuclear Information System (INIS)

    Explained is the cataract as the lens is one of the most sensitive tissues to radiation, for considering the possible ophthalmological radiation disorder by the Fukushima Nuclear Power Plant Accident (2011). Radiation cataract is observed at 1-2 years after acute high dose exposure, but at low dose, it appears as the late effect. In fact, the disease related to exposure is found in as many as 25% of Chernobyl workers at >10 years post its Accident. Pathologic feature of radiation cataract has been thought to be the posterior subcapsular type. However, the cortical type is shown to be also noted by recent findings in the Chernobyl Accident, in the lens 30-45 years after radiotherapy of infants for dermovascular angioma, in astronaut, and in Hiroshima A-bomb survivors. Acute exposure to 0.5-1.5 Gy results in lens opacity and at >5 Gy, cataract with visual dysfunction. Higher cataract prevalence is recently reported seen in the therapeutic cardiac fluoroscopy where the medians of accumulated doses are 6.0 Sv in doctors and 1.5 Sv in nurses and radiologists. Astronauts exposed at >8 mSv have higher prevalence. Animal experiments have shown that the lens sensitivity to radiation depends on the age. Clinical experience of radiotherapy of the angioma above has suggested the higher sensitivity in young generation, which is supported by the fact that, among 114 inhabitants of 60Co-contaminated building, the dose effect is observable in 61 inhabitants of the age <20 y alone. linear threshold theory (LNT) hypothesis cannot be excluded by above evidences and there is conceivably no (or extremely low) threshold for cataract. The younger the age of exposure, the higher the risk of cataract, and thereby the lens in young generation should be carefully followed-up in Fukushima. (T.T.)

  2. Mechanisms for radiation damage in DNA

    International Nuclear Information System (INIS)

    In this project the author has proposed several mechanisms for radiation damage to DNA and its constituents, and has detailed a series of experiments utilizing electron spin resonance spectroscopy, HPLC, GC-mass spectroscopy and ab initio molecular orbital calculations to test the proposed mechanisms. In this years work he has completed several experiments on the role of hydration water on DNA radiation damage, continued the investigation of the localization of the initial charges and their reactions on DNA, investigated protonation reactions in DNA base anions, and employed ab initio molecular orbital theory to gain insight into the initial events of radiation damage to DNA. Ab initio calculations have provided an understanding of the energetics evolved in anion and cation formation, ion radical transfer in DNA as well as proton transfer with DNA base pair radical ions. This has been extended in this years work to a consideration of ionization energies of various components of the DNA deoxyribose backbone and resulting neutral sugar radicals. This information has aided the formation of new radiation models for the effect of radiation on DNA. During this fiscal year four articles have been published, four are in press, one is submitted and several more are in preparation. Four papers have been presented at scientific meetings. This years effort will include another review article on the open-quotes Electron Spin Resonance of Radiation Damage to DNAclose quotes

  3. The expected radiation damage of CSNS target

    Science.gov (United States)

    Yin, W.; Yu, Q. Z.; Lu, Y. L.; Wang, S. L.; Tong, J. F.; Liang, T. J.

    2012-12-01

    The radiation damage to the tungsten target and its SS316 vessel for Chinese Spallation Neutron Source (CSNS) has been estimated with a Monte-Carlo simulation code MCNPX2.5.0. We compare the effects on the radiation damage due to two different proton beam profiles: a uniform distribution and a Gaussian distribution. We also discuss the dependence of the radiation damage estimation on different physics models. The results show the peak displacement productions in vessel and the fourth target plate are 2.5 and 5.5 dpa/y, respectively, under a Gaussian proton beam. The peak helium productions in the vessel and the fourth target are 305 and 353 appm/y, respectively, under the same proton beam. Based on these results and the allowable dpa values we have estimated the lifetime of the tungsten target and its vessel.

  4. The expected radiation damage of CSNS target

    Energy Technology Data Exchange (ETDEWEB)

    Yin, W., E-mail: wenyin@aphy.iphy.ac.cn [Engineering Center of CSNS Target Station and Instruments, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Yu, Q.Z. [Engineering Center of CSNS Target Station and Instruments, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Lu, Y.L.; Wang, S.L.; Tong, J.F. [Experimental System of CSNS, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Liang, T.J. [Engineering Center of CSNS Target Station and Instruments, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2012-12-15

    The radiation damage to the tungsten target and its SS316 vessel for Chinese Spallation Neutron Source (CSNS) has been estimated with a Monte-Carlo simulation code MCNPX2.5.0. We compare the effects on the radiation damage due to two different proton beam profiles: a uniform distribution and a Gaussian distribution. We also discuss the dependence of the radiation damage estimation on different physics models. The results show the peak displacement productions in vessel and the fourth target plate are 2.5 and 5.5 dpa/y, respectively, under a Gaussian proton beam. The peak helium productions in the vessel and the fourth target are 305 and 353 appm/y, respectively, under the same proton beam. Based on these results and the allowable dpa values we have estimated the lifetime of the tungsten target and its vessel.

  5. Attenuative effects of G-CSF in radiation induced intestinal injury

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Joong Sun; Gong, Eun Ji; Kim, Sung Dae; Heo, Kyu; Ryoo, Seung Bum; Yang, Kwang Mo [Dongnam Institute of Radiological and Medical Sciences, Busan (Korea, Republic of)

    2011-11-15

    Granulocyte colony stimulating factor (G-CSF) has been reported to protect from radiationinduced myelosuppression. Growing evidence suggests that G-CSF also has many important non-hematopoietic functions in other tissues, including the intestine (Kim et al., 2010; Kim et al., 2011). However, little is known about the influence of G-CSF on intestinal injury. Examination 12 hours after radiation (5 Gy) revealed that the G-CSF treated mice were significantly protected from apoptosis of jejunal crypt, compared with radiation controls. G-CSF treatment attenuated intestinal morphological changes such as decreased survival crypt, the number of villi, villous shortening, crypt depth and length of basal lamina of 10 enterocytes compared with the radiation control 3.5 days after radiation (10 Gy). G-CSF attenuated the change of peripheral blood from radiation-induced myelosuppression and displayed attenuation of mortality in lethally-irradiated (10 Gy) mice. The present results support the suggestion that G-CSF administrated prior to radiation plays an important role in the survival of irradiated mice, possibly due to the protection of hematopoietic cells and intestinal stem cells against radiation. The results indicate that G-CSF protects from radiation-mediated intestinal damage and from hematopoietic injury. G-CSF treatment may be useful clinically in the prevention of injury following radiation.

  6. Attenuative effects of G-CSF in radiation induced intestinal injury

    International Nuclear Information System (INIS)

    Granulocyte colony stimulating factor (G-CSF) has been reported to protect from radiationinduced myelosuppression. Growing evidence suggests that G-CSF also has many important non-hematopoietic functions in other tissues, including the intestine (Kim et al., 2010; Kim et al., 2011). However, little is known about the influence of G-CSF on intestinal injury. Examination 12 hours after radiation (5 Gy) revealed that the G-CSF treated mice were significantly protected from apoptosis of jejunal crypt, compared with radiation controls. G-CSF treatment attenuated intestinal morphological changes such as decreased survival crypt, the number of villi, villous shortening, crypt depth and length of basal lamina of 10 enterocytes compared with the radiation control 3.5 days after radiation (10 Gy). G-CSF attenuated the change of peripheral blood from radiation-induced myelosuppression and displayed attenuation of mortality in lethally-irradiated (10 Gy) mice. The present results support the suggestion that G-CSF administrated prior to radiation plays an important role in the survival of irradiated mice, possibly due to the protection of hematopoietic cells and intestinal stem cells against radiation. The results indicate that G-CSF protects from radiation-mediated intestinal damage and from hematopoietic injury. G-CSF treatment may be useful clinically in the prevention of injury following radiation.

  7. Nanofoams Response to Radiation Damage

    International Nuclear Information System (INIS)

    Conclusions of this presentation are: (1) np-Au foams were successfully synthesized by de-alloying process; (2) np-Au foams remain porous structure after Ne ion irradiation to 1 dpa; (3) SFTs were observed in irradiated np-Au foams with highest and intermediate flux, while no SFTs were observed with lowest flux; (4) SFTs were observed in irradiated np-Au foams at RT, whereas no SFTs were observed at LNT irradiation; (5) The diffusivity of vacancies in Au at RT is high enough so that the vacancies have enough time to agglomerate and thus collapse. As a result, SFTs were formed; (6) The high flux created much more damage/time, vacancies don't have enough time to diffuse or recombine. As a result, SFTs were formed.

  8. Radiation damage in calcium sulfate

    International Nuclear Information System (INIS)

    We used the techniques of Electron Paramagnetic Resonance (EPR) to study the free radicals produced by X-radiation in natural crystals of Gypsum (CaSO42H20). We observed the formation of four free radicals. The spectra of these radicals are overlapped, being separated by power and temperature variation measurements. Two radicals were univocal identified, as being of OH+ and 02H+. We suggest the assignment of SO4- and O2- to two other radicals. From angular variation measurements, we determined the components of tensors ↔g and ↔A of the radicals OH- and O2H-. (author)

  9. Tooth-germ damage by ionizing radiation

    International Nuclear Information System (INIS)

    Experiments on animals (four-week-old dogs) were conducted in an investigation made to study the possibility of dose-dependent tooth-germ damage produced by ionizing radiation. The individual doses were 50 R and 200 R, respectively, and they were administered once to three times at weekly intervals. Hyperemia and edemata could be observed on tooth-germ pulps from 150 R onward. Both of these conditions became more acute as the radiation dose increased (from 150 R to 600 R). Possible damage to both the dentin and enamel is pointed out. (author)

  10. Mechanisms for radiation damage in DNA

    International Nuclear Information System (INIS)

    Radiation damage to DNA results from the direct interaction of radiation with DNA where positive ions, electrons and excited states are formed in the DNA, and the indirect effect where radical species formed in the surrounding medium by the radiation attack the DNA. The primary mechanism proposed for radiation damage, by the direct effect, is that positive and negative ions formed within the DNA strand migrate through the stacked DNA bases. The ions can then recombine, react with the DNA bases most likely to react by protonation of the anion and deprotonation or hydroxylation of the cation or transfer out of the DNA chain to the surrounding histone protein. This work as aimed at understanding the possible reactions of the DNA base ion radicals, as well as their initial distribution in the DNA strand. 31 refs

  11. Radiation damage of polymers in ultrasonic fields

    International Nuclear Information System (INIS)

    Radiation damage has always been a topic of great interest in various fields of sciences. In this work, an attempt is made to probe into the effect of subthreshold ultrasonic waves on the radiation damage created by irradiation of deuterons in polymer samples wherein the polymer samples act as model systems. Two equal volumes of radiation damage were produced in a single polymer sample wherein a standing wave of ultrasound was introduced into one. Three polymers namely, Polycarbonate, Polymethylmethacrylate and Polyvinyl chloride were used in this work. Four independent techniques were used to analyze the irradiated samples and visualize the radiation damage. Interferometric measurements give a measure of the refractive index modulation in the irradiated sample. Polymers, being transparent, do not absorb in the visible region of the electromagnetic spectrum. UV-Vis absorption spectroscopy shows absorption peaks in the visible region in irradiated polymer samples. Ion irradiation causes coloration of polymers. The light microscope is used to measure the absorption of white light by the irradiated polymers. Positron annihilation spectroscopy is used to obtain a measure of the open volume created by irradiation in polymers. A comparison between the irradiated region and the region exposed to ultrasonic waves simultaneously with irradiation in a polymer sample shows the polymer specific influence of the ultrasonic standing wave. (orig.)

  12. Undulator Radiation Damage Experience at LCLS

    Energy Technology Data Exchange (ETDEWEB)

    Nuhn, H. D. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Field, C. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Mao, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Levashov, Y. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Santana, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Welch, J. N. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Wolf, Z. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-01-06

    The SLAC National Accelerator Laboratory has been running the Linac Coherent Light Source (LCLS), the first x-ray Free Electron Laser since 2009. Undulator magnet damage from radiation, produced by the electron beam traveling through the 133-m long straight vacuum tube, has been and is a concern. A damage measurement experiment has been performed in 2007 in order to obtain dose versus damage calibrations. Radiation reduction and detection devices have been integrated into the LCLS undulator system. The accumulated radiation dose rate was continuously monitored and recorded. In addition, undulator segments have been routinely removed from the beamline to be checked for magnetic (50 ppm, rms) and mechanic (about 0.25 µm, rms) changes. A reduction in strength of the undulator segments is being observed, at a level, which is now clearly above the noise. Recently, potential sources for the observed integrated radiation levels have been investigated. The paper discusses the results of these investigation as well as comparison between observed damage and measured dose accumulations and discusses, briefly, strategies for the new LCLS-II upgrade, which will be operating at more than 300 times larger beam rate.

  13. Radiation damage of polymers in ultrasonic fields

    Energy Technology Data Exchange (ETDEWEB)

    Anbalagan, Poornnima

    2008-07-01

    Radiation damage has always been a topic of great interest in various fields of sciences. In this work, an attempt is made to probe into the effect of subthreshold ultrasonic waves on the radiation damage created by irradiation of deuterons in polymer samples wherein the polymer samples act as model systems. Two equal volumes of radiation damage were produced in a single polymer sample wherein a standing wave of ultrasound was introduced into one. Three polymers namely, Polycarbonate, Polymethylmethacrylate and Polyvinyl chloride were used in this work. Four independent techniques were used to analyze the irradiated samples and visualize the radiation damage. Interferometric measurements give a measure of the refractive index modulation in the irradiated sample. Polymers, being transparent, do not absorb in the visible region of the electromagnetic spectrum. UV-Vis absorption spectroscopy shows absorption peaks in the visible region in irradiated polymer samples. Ion irradiation causes coloration of polymers. The light microscope is used to measure the absorption of white light by the irradiated polymers. Positron annihilation spectroscopy is used to obtain a measure of the open volume created by irradiation in polymers. A comparison between the irradiated region and the region exposed to ultrasonic waves simultaneously with irradiation in a polymer sample shows the polymer specific influence of the ultrasonic standing wave. (orig.)

  14. Effects of radiation damage on SYNROC

    International Nuclear Information System (INIS)

    Concern has been expressed in several quarters that the integrity of SYNROC as a waste form might be compromised by the effects of alpha radiation damage on its constituent minerals. The evidence discussed herein addresses that concern. Radiation damage to crystal lattices is caused dominantly by alpha emitters (actinide elements) present in zirconolite and perovskite phases. We have seen that the zirconolite phase in SYNROC containing 10% of HLW would require about 106 years before becoming completely metamict, i.e., losing the capacity to diffract X-rays. By this time, the alpha activity in SYNROC would have declined to a value smaller than that present in a natural uranium ore body. This level of activity can be considered effectively safe for a waste form buried in a suitable geologic repository. Moreover, even when metamict, the zirconolite continues to demonstrate a remarkable capacity to immobilize U, Th and their decay daughter products. The isotopic measurements on Sri Lanka and Jimberlana zirconolites demonstrated that these metamict minerals had behaved as closed systems for U, Th and Pb for periods of 560 and 2500 million years, respectively, despite intense radiation damage (SYNROC equivalent ages, about or greater than 109 years). Moreover, the Sri Lanka zirconolite was sufficiently tight to immobilize a considerable proportion of radiogenic helium, one of the most mobile of elements, for 560 million years. Our data on perovskite are limited and more work remains to be done. Nevertheless, present results indicate that perovskites are even more resistant to radiation damage than zirconolite

  15. Flexible lead-free radiation shields for gamma radiation : radiation vulcanization and gamma attenuation efficiency

    International Nuclear Information System (INIS)

    In the present study, a lead-free radiation shield is developed by synthesizing radiation crosslinked PDMS/Bi2O3 polymer composites. The composites were crosslinked by 60Co γ-radiation and their attenuation efficiency was checked against 241Am. Americium-241 is an α-emitter (t1/2 ∼ 432.7 years) which is followed by γ-emission (∼59.5 keV). It is one of the most important sources of radiation exposure during nuclear fuel processing. Composites of different compositions were synthesised through shear mixing in Brabender plasticordar and were crosslinked to different extent by gamma radiation. Figure 1 shows changes in the mechanical properties of the composites. It can be seen that with the increase in radiation dose modulus of the composites increased substantially. This observation highlights increase in the crosslinking density. Elongation at break on the other hand decreased considerably, which has been attributed to the reduction in inter-chain slippage due to crosslinking. In figure 2, the attenuation in PDMS/Bi2O3 (70%) composites have been presented. It can be seen that even with 1.5 mm sheet % attenuation was 91.2% and the flexibility and mechanical properties of the composites were very good. These results suggest that these composites can be an excellent candidate for high energy flexible radiation shielding

  16. Experimental study on radiation attenuation by a water film

    International Nuclear Information System (INIS)

    Radiative transfer through a water film was investigated. Films with average thicknesses between 100 and 380μm were studied. The film thickness was measured using an optical method based on the attenuation of a near infrared laser beam. The attenuation of infrared radiation on a wide spectral range was determined simultaneously by using a FTIR spectrometer. A high attenuation efficiency was observed even for such small film thicknesses, which demonstrated the shielding effect of water films. Extension of present observations to high temperature sources allows the evaluation of the film absorption, which was predicted in the range 60–95% for films between 100μm and 1 mm and for incident radiation from blackbodies up to 1473 K. - Highlights: • An optical method was used to measure water film thickness. • Infrared radiation attenuation was derived from FTIR spectroscopic data. • The shielding effect of water film was confirmed. • Attenuation up to 95% was obtained for films less than 1 mm thick

  17. Measurement of radiation damage on silica aerogel Cerenkov radiator

    CERN Document Server

    Sahu, S K; Suda, R; Enomoto, R; Peng, K C; Wang, C H; Adachi, I; Amami, M; Chang, Y H; Guo, R S; Hayashi, K; Iijima, T; Sumiyoshi, T; Yoshida, Y

    1996-01-01

    We measured the radiation damage on silica aerogel \\v Cerenkov radiators originally developed for the B-factory experiment at KEK. Refractive index of the aerogel samples ranged from 1.012 to 1.028. The samples were irradiated up to 9.8~MRad of equivalent dose. Measurements of transmittance and refractive index were carried out and these samples were found to be radiation hard. Deteriorations in transparency and changes of refractive index were observed to be less than 1.3\\% and 0.001 at 90\\% confidence level, respectively. Prospects of using aerogels under high-radiation environment are discussed.

  18. Measurement of radiation damage on a silica aerogel Cherenkov radiator

    International Nuclear Information System (INIS)

    We measured the radiation damage on silica aerogel Cherenkov radiators originally developed for the B-factory experiment at KEK. The refractive index of the aerogel samples ranged from 1.012 to 1.028. The samples were irradiated up to 9.8 Mrad of equivalent dose. Measurements of transmittance and refractive index were carried out and these samples were found to be radiation hard. Deteriorations in transparency and changes of refractive index were observed to be less than 1.3% and 0.001 at 90% confidence level, respectively. Prospects of using aerogels under high-radiation environment are discussed. (orig.)

  19. Ketoconazole attenuates radiation-induction of tumor necrosis factor

    International Nuclear Information System (INIS)

    Previous work has demonstrated that inhibitors of phospholipase A2 attenuate ionizing radiation-induced arachidonic acid production, protein kinase C activation, and prevent subsequent induction of the tumor necrosis factor gene. Because arachidonic acid contributes to radiation-induced tumor necrosis factor expression, the authors analyzed the effects of agents which alter arachidonate metabolism on the regulation of this gene. Phospholipase A2 inhibitors quinicrine, bromphenyl bromide, and pentoxyfylline or the inhibitor of lipoxygenase (ketoconazole) or the inhibitor of cycloxygenase (indomethacine) were added to cell culture 1 h prior to irradiation. Radiation-induced tumor necrosis factor gene expression was attenuated by each of the phospholipase A2 inhibitors (quinicrine, bromphenylbromide, and pentoxyfylline). Furthermore, ketoconazole attenuated X ray induced tumor necrosis factor gene expression. Conversely, indomethacin enhanced tumor necrosis factor expression following irradiation. The finding that radiation-induced tumor necrosis factor gene expression was attenuated by ketoconazole suggests that the lipoxygenase pathway participates in signal transduction preceding tumor necrosis factor induction. Enhancement of tumor necrosis factor expression by indomethacin following irradiation suggests that prostaglandins produced by cyclooxygenase act as negative regulators of tumor necrosis factor expression. Inhibitors of tumor necrosis factor induction ameliorate acute and subacute sequelae of radiotherapy. The authors propose therefore, that ketoconazole may reduce acute radiation sequelae such as mucositis and esophagitis through a reduction in tumor necrosis factor induction or inhibition of phospholipase A2 in addition to its antifungal activity. 25 refs., 2 figs

  20. Radiation damage effects in silicon detectors

    International Nuclear Information System (INIS)

    Radiation damage in silicon detectors produced by monoenergetic 14 MeV neutrons, 25 MeV protons and 20 keV X-rays was investigated. The irradiation was performed up to fluences of 1012 particles per cm2 resp. 5 kGy in short time exposures of less than 1 hour. The resulting increase of the leakage current (damage rate), change of the resistivity (impurity removal) and charge collection deficiency (decrease of trapping time constant) is discussed. Long term storage at room temperature and short term heat treatments showed appreciable annealing effects

  1. Mechanisms for radiation damage in DNA

    International Nuclear Information System (INIS)

    In this project we have proposed several mechanisms for radiation damage and recently radiation protection to DNA and its constituents, and have detailed a series of experiments utilizing electron spin resonance spectroscopy, HPLC and GC-mass spectroscopy to test the proposed mechanisms. In this years' work we have continued the investigation of the localization of the initial charges on DNA after irradiation through experiment and through the use of ab initio molecular orbital theory. The experimental results and MO calculations are in agreement that cytosine, not thymine, is likely the principal locus for excess charge; whereas guanine is confirmed as the initial site for the cationic charge. The mechanism for the anion localization on cytosine is clarified by MO calculations of DNA base pair and stacked base pair (GC/AT) ion radicals. In addition predictions made from a new model of ion transfer in DNA are tested and confirmed by an ESR investigation of irradiated single stranded DNA. In this years' effort in joint work with Wake Forest University we have also made excellent progress in the study of products produced from the direct effect of radiation on DNA. The release of unaltered bases and DNA base damage products are shown to be a function of hydration layer and evidence for a demarcation between the direct and indirect effect of radiation is presented. DNA base products from irradiations at ambient temperatures are shown to be those that would be predicted from ESR studies at low temperatures. In addition initial studies of radiation effects on DNA-protein complexes and certain sensitive amino acids have been initiated to shed light on the role of histones on DNA radiation damage. 16 refs., 2 figs., 1 tab

  2. Radiation damage in nanostructured metallic films

    Science.gov (United States)

    Yu, Kaiyuan

    High energy neutron and charged particle radiation cause microstructural and mechanical degradation in structural metals and alloys, such as phase segregation, void swelling, embrittlement and creep. Radiation induced damages typically limit nuclear materials to a lifetime of about 40 years. Next generation nuclear reactors require materials that can sustain over 60 - 80 years. Therefore it is of great significance to explore new materials with better radiation resistance, to design metals with favorable microstructures and to investigate their response to radiation. The goals of this thesis are to study the radiation responses of several nanostructured metallic thin film systems, including Ag/Ni multilayers, nanotwinned Ag and nanocrystalline Fe. Such systems obtain high volume fraction of boundaries, which are considered sinks to radiation induced defects. From the viewpoint of nanomechanics, it is of interest to investigate the plastic deformation mechanisms of nanostructured films, which typically show strong size dependence. By controlling the feature size (layer thickness, twin spacing and grain size), it is applicable to picture a deformation mechanism map which also provides prerequisite information for subsequent radiation hardening study. And from the viewpoint of radiation effects, it is of interest to explore the fundamentals of radiation response, to examine the microstructural and mechanical variations of irradiated nanometals and to enrich the design database. More importantly, with the assistance of in situ techniques, it is appealing to examine the defect generation, evolution, annihilation, absorption and interaction with internal interfaces (layer interfaces, twin boundaries and grain boundaries). Moreover, well-designed nanostructures can also verify the speculation that radiation induced defect density and hardening show clear size dependence. The focus of this thesis lies in the radiation response of Ag/Ni multilayers and nanotwinned Ag

  3. Radiation damage in nuclear waste materials

    International Nuclear Information System (INIS)

    Final disposal of high-level radioactive nuclear waste is usually envisioned in some sort of ceramic material. The physical and chemical properties of host materials for nuclear waste can be altered by internal radiation and consequently their structural integrity can be jeopardized. Assessment of long-term performance of these ceramic materials is therefore vital for a safe and successful disposal. This paper presents an overview of studies on several possible candidate materials for immobilization of fission products and actinides, such as spinel (MgAl2O4), perovskite (CaTiO3), zircon (ZrSiO4), and pyrochlore (Gd2Ti2O7 and Gd2Zr2O7). The basic microscopic picture of radiation damage in ceramics consists of atomic displacements and ionization. In many cases these processes result in amorphization (metaminctization) of irradiated material. The evolution of microscopic structure during irradiation leads to various macroscopic radiation effects. The connection between microscopic and macroscopic picture is in most cases at least qualitatively known and studies of radiation induced microscopic changes are therefore an essential step in the design of a reliable nuclear waste host material. The relevance of these technologically important results on our general understanding of radiation damage processes and on current research efforts in Slovenia is also addressed. (author)

  4. Evaluation of radiation damage using nonlinear ultrasound

    International Nuclear Information System (INIS)

    Nonlinear ultrasound was used to monitor radiation damage in two reactor pressure vessel (RPV) steels. The microstructural changes associated with radiation damage include changes in dislocation density and the formation of precipitates, and nonlinear ultrasonic waves are known to be sensitive to such changes. Six samples each of two different RPV steels were previously irradiated in the Rheinsberg power reactor to two fluence levels, up to 1020 n/cm2 (E > 1 MeV). Longitudinal waves were used to measure the acoustic nonlinearity in these samples, and the results show a clear increase in the measured acoustic nonlinearity from the unirradiated state to the medium dose, and then a decrease from medium dose to high dose.

  5. Radiation Damage in the LHCb VELO

    CERN Multimedia

    Harrison, Jon

    2011-01-01

    The VErtex LOcator (VELO) is a silicon strip detector designed to reconstruct particle tracks and vertices produced by proton-proton interactions near to the LHCb interaction point. The excellent track resolution and decay vertex separation provided by the VELO are essential to all LHCb analyses. For the integrated luminosity delivered by the LHC up to the end of $2011$ the VELO is exposed to higher particle fluences than any other silicon detector of the four major LHC experiments. These proceedings present results from radiation damage studies carried out during the first two years of data taking at the LHC. Radiation damage has been observed in all of the $88$ VELO silicon strip sensors, with many sensors showing evidence of type-inversion in the highest fluence regions. Particular attention has been given to the two \

  6. Radiation damage at LHCb, results and expectations

    CERN Multimedia

    Faerber, Christian

    2011-01-01

    The LHCb Detector is a single-arm spectrometer at the LHC designed to detect new physics through measuring CP violation and rare decays of heavy flavor mesons. The detector consists of vertex detector, tracking system, dipole magnet, 2 RICH detectors, em. calorimeter, hadron calorimeter, muon detector which all use different technologies and suffer differently from radiation damage. These radiation damage results and the investigation methods will be shown. The delivered luminosity till July 2011 was about 450 pb−1. The Vertex detector receives the highest particle flux at LHCb. The currents drawn by the silicon sensors are, as expected, increasing proportional to the integrated luminosity. The highest irradiaton regions of the n-bulk silicon sensors are observed to have recently undergone space charge sign inversion. The Silicon Trackers show increasing leakage currents comparable with earlier predictions. The electromagentic calorimeter and hadron calorimeter suffer under percent-level signal decrease whi...

  7. Radiation-induced damage to DNA

    International Nuclear Information System (INIS)

    This short survey focuses on the main radiation-induced base lesions that have been identified within cellular DNA. For this purpose, sensitive assays that are aimed at measuring a few modifications per 107 normal bases were set-up. In that respect high performance liquid chromatography - tandem mass spectrometry (CLHP-MS/MS) was found to be able to single out the formation of 9 oxidized nucleosides and two modified nucleo-bases out of the 70 oxidative base lesions that have been identified in model systems. As a striking result, it was found that in the DNA of γ-irradiated human monocytes, the formamide-pyrimidine derivative of guanine is produced in a higher yield than the ubiquitous 8-oxo-7,8-dihydro-guanine damage, both arising from the same radical precursor. However, relatively high doses of ionizing radiation (> 20 Gy) have to be applied in order to detect an increase in the level of the damage. This is due to the low efficiency for both low and high LET radiations to generate oxidative damage to DNA on one hand and the occurrence of artifactual oxidation of the overwhelming normal bases during DNA extraction on the other hand. Interestingly, a modified comet assays that involves the combined use of the alkaline single gel electrophoretic technique and DNA repair N-glycosylases has allowed the detection of three main types of radiation-induced damage within the dose range 0.3 Gy -10 Gy. It appears that the total of frank DNA strand breaks and alkali-labile sites is similar to the sum of oxidized pyrimidine bases and modified purine bases that are recognized by the endonuclease Ill protein and the formamide-pyrimidine DNA N-glycosylase respectively. (author)

  8. Radiation damage in Luna 20 soil.

    Science.gov (United States)

    Phakey, P. P.; Price, P. B.

    1973-01-01

    As an extension of previous studies of radiation damage produced by heavy solar flare ions in lunar soils, high-voltage electron microscopy and electron diffraction procedures were used to rank a Luna 20 sample among the other soils returned by Soviet and American lunar missions. Micron-sized soil grains from the Luna 20 mission are the most lightly irradiated, in contrast to micron-sized grains from Luna 16 soil, which are the most heavily irradiated.

  9. Characteristics of liver tissue for attenuate the gamma radiation

    International Nuclear Information System (INIS)

    It was determined the lineal attenuation coefficient of hepatic tissue before gamma radiation of a source of 137 Cs. When exposing organic material before X or gamma radiation fields, part of the energy of the photons is absorbed by the material, while another part crosses it without producing any effect. The quantity of energy that is absorbed is a measure of the dose that receives the material. The three main mechanisms by means of which the gamma rays interacting with the matter are: The Photoelectric Effect, the Compton dispersion and the Even production; the sum of these three processes is translated in the attenuation coefficient of the radiation. In this work we have used hepatic tissue of bovine, as substitute of the human hepatic tissue, and we have measured the lineal attenuation coefficient for photons of 0.662 MeV. Through a series of calculations we have determined the lineal attenuation coefficient for photons from 10-3 to 10-5 MeV and the measured coefficient was compared with the one calculated. (Author)

  10. Membrane structure and radiation and hyperthermic damage

    International Nuclear Information System (INIS)

    The general structure of the biological membrane and its involvement in cell damage from radiation and hyperthermic insults are discussed using bacterial cells as an example. Bacterial cells are useful models for these types of studies because they possess a simple membrane system whose composition can be readily altered. Also, various strains exist having different sensitivities to radiation and heat. For example, the response of Escherichia coli cells to ionizing radiation is found to be related to the degree of association between its DNA and membrane. The cell membrane, particularly the lipid component, is an important target in hyperthermic cell killing. The composition and organization of the membrane lipids can influence a cell's response to heat. Heat-induced changes in membrane lipids lead to altered distribution of E. coli proteins, particularly their translocation to the outer membrane. These and other aspects are discussed in this review. (author)

  11. Identifying and quantifying radiation damage at the atomic level

    Energy Technology Data Exchange (ETDEWEB)

    Gerstel, Markus [University of Oxford, South Parks Road, Oxford OX1 3QU (United Kingdom); Deane, Charlotte M. [University of Oxford, 1 South Parks Road, Oxford OX1 3TG (United Kingdom); Garman, Elspeth F., E-mail: elspeth.garman@bioch.ox.ac.uk [University of Oxford, South Parks Road, Oxford OX1 3QU (United Kingdom)

    2015-02-14

    A metric indicating the relative level of specific radiation damage for individual atoms, that can be calculated from refined and deposited protein structure models, is presented. Radiation damage impedes macromolecular diffraction experiments. Alongside the well known effects of global radiation damage, site-specific radiation damage affects data quality and the veracity of biological conclusions on protein mechanism and function. Site-specific radiation damage follows a relatively predetermined pattern, in that different structural motifs are affected at different dose regimes: in metal-free proteins, disulfide bonds tend to break first followed by the decarboxylation of aspartic and glutamic acids. Even within these damage motifs the decay does not progress uniformly at equal rates. Within the same protein, radiation-induced electron density decay of a particular chemical group is faster than for the same group elsewhere in the protein: an effect known as preferential specific damage. Here, B{sub Damage}, a new atomic metric, is defined and validated to recognize protein regions susceptible to specific damage and to quantify the damage at these sites. By applying B{sub Damage} to a large set of known protein structures in a statistical survey, correlations between the rates of damage and various physicochemical parameters were identified. Results indicate that specific radiation damage is independent of secondary protein structure. Different disulfide bond groups (spiral, hook, and staple) show dissimilar radiation damage susceptibility. There is a consistent positive correlation between specific damage and solvent accessibility.

  12. In-situ radiation damage in Mg

    International Nuclear Information System (INIS)

    The creep rate in the low flux regions at the ends of the fuel channels is important for predicting fuel channel sag and pressure tube-to-calandria tube contact. This creep rate is partly determined by the accumulation of radiation damage, which is a function of flux. There appears to be a threshold flux, below which no dislocation loop nucleation occurs in the matrix of the material. This may or may not correspond to a condition of maximum hardening. We are attempting to verify this observation by examining the effect of dose rate on radiation damage in Mg. These observations will be useful in interpreting the power reactor data for pressure tubes. Magnesium specimens of 99.9% purity were prepared by electropolishing and irradiated in a transmission electron microscope (TEM) at 300 kV. Images were collected using a charge coupled device (CCD) camera and used to compare equivalent accumulated damage for low and high flux conditions. Experiments show that a threshold flux exists, with generally no observation of new dislocation loops below the threshold flux, and nucleation of new dislocation loops above the threshold flux. Nucleation of dislocation loops occurs heterogeneously both at pre-existing network dislocations and at other sites within the matrix. Although preferential nucleation at dislocations is anticipated, the heterogeneous nucleation within the matrix appears to be related to the presence of small precipitates. Very high purity Mg will be used to verify this hypothesis. (author)

  13. Radiation damage in the LHCb VELO

    Energy Technology Data Exchange (ETDEWEB)

    Dossett, D., E-mail: d.a.dossett@warwick.ac.uk [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom)

    2013-08-01

    LHCb is a dedicated experiment to study new physics in the decays of beauty and charm hadrons at the Large Hadron Collider (LHC) at CERN. The Vertex Locator (VELO) is a silicon micro-strip detector which surrounds the LHCb interaction point and provides μm resolution of charged tracks and vertex positions. The tip of the VELO sensors is predicted to receive a dose of 0.5×10{sup 13} 1-MeV n{sub eq}/cm{sup 2} per fb of data. The highest fluence of any silicon tracker at the four major LHC experiments. Radiation damage studies have been carried out during the first two years of data taking at LHCb for all 88 sensors of the VELO. Radiation damage has been observed in all sensors, with those sensors in the highest fluence regions showing evidence of type inversion. Radiation induced charge loss due to the second metal layer on the sensors is also observed.

  14. Radiation damage by heavy ion irradiation

    International Nuclear Information System (INIS)

    Various phenomena caused by heavy ion irradiation are introduced. The experiments concerning this radiation damage are in progress with small size heavy ion accelerators. The accelerated ions are Ar+, Xe+, He+, and Mo+. The samples to be irradiated are Al and Al alloy, Nb and Nb alloy, and W. As the result of heavy ion irradiation, surface sputtering is caused. The rate of sputtering depends on the energy of incident particles, the kinds of particles, and the direction of crystal axis in relation to that of incident particles. Blistering is caused by gaseous atoms in crystals. Usually, the gaseous atoms are injected into the crystals. The phenomenon of blistering proceeds to flaking by further irradiation. Due to these phenomena, the wall of a fusion reactor gets big damage, and the flaked material becomes the impurities in the plasma. Interstitial atom clusters are formed by the atoms ejected from the lattice positions in crystals. (Kato, T.)

  15. Radiation damage to DNA-protein complexes

    Czech Academy of Sciences Publication Activity Database

    Spotheim-Maurizot, M.; Davídková, Marie

    2011-01-01

    Roč. 261, zima (2011), s. 1-10. ISSN 1742-6588. [COST Chemistry CM0603-MELUSYN Joint Meeting Damages Induced in Biomolecules by Low and High Energy Radiations. Paříž, 09.03.2010-12.03.2010] R&D Projects: GA AV ČR IAA1048103; GA AV ČR KJB4048401; GA MŠk 1P05OC085; GA MŠk OC09012; GA AV ČR IAB1048901 Institutional research plan: CEZ:AV0Z10480505 Keywords : radiolysis * molecular-dynamics simulation * hydroxyl radical attack * induced strand breakage Subject RIV: BO - Biophysics

  16. Neutron radiation damage studies on silicon detectors

    International Nuclear Information System (INIS)

    Effects of neutron radiation on electrical properties of Si detectors have been studied. At high neutron fluence (Φn ≥ 1012 n/cm2), C-V characteristics of detectors with high resistivities (ρ ≥ 1 kΩ-cm) become frequency dependent. A two-trap level model describing this frequency dependent effect is proposed. Room temperature anneal of neutron damaged (at LN2 temperature) detectors shows three anneal stages, while only two anneal stages were observed in elevated temperature anneal. 19 refs., 14 figs

  17. Compilation of radiation damage test data. I

    International Nuclear Information System (INIS)

    This report summarizes radiation damage test data on commercially available organic cable insulation and jacket materials: ethylene-propylene rubber, Hypalon, neoprene rubber, polyethylene, polyurethane, polyvinylchloride, silicone rubber, etc. The materials have been irradiated in a nuclear reactor to integrated absorbed doses from 5 X 105 to 5 X 106 Gy. Mechanical properties, e.g. tensile strength, elongation at break, and hardness, have been tested on irradiated and non-irradiated samples. The results are presented in the form of tables and graphs, to show the effect of the absorbed dose on the measured properties. (Auth.)

  18. Studies on the strategies of minimizing radiation damage

    International Nuclear Information System (INIS)

    We studied on the strategies of minimizing radiation damage in animal system. To this end we studied following areas of research 1) mechanisms involved in bone marrow damage after total body irradiation, 2) extraction of components that are useful in protecting hematopoietic system from radiation damage, 3) cell therapy approach in restoring the damaged tissue, 4) development of radioprotective chemical reagent, and 5) epidemiological study on the population that had been exposed to radiation

  19. Studies on the strategies of minimizing radiation damage

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Hee Yong; Sohn, Young Sook

    1998-04-01

    We studied on the strategies of minimizing radiation damage in animal system. To this end we studied following areas of research (1) mechanisms involved in bone marrow damage after total body irradiation, (2) extraction of components that are useful in protecting hematopoietic system from radiation damage, (3) cell therapy approach in restoring the damaged tissue, (4) development of radioprotective chemical reagent, and (5) epidemiological study on the population that had been exposed to radiation.

  20. Radiation damage of transition metal carbides

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, G.

    1991-01-01

    In this grant period we have investigated electrical properties of transition metal carbides and radiation-induced defects produced by low-temperature electron irradiation in them. Special attention has been given to the composition VC[sub 0.88] in which the vacancies on the carbon sublattice of this fcc crystal order to produce a V[sub 8]C[sub 7] superlattice. The existence of this superlattice structure was found to make the crystal somewhat resistant to radiation damage at low doses and/or at ambient temperature. At larger doses significant changes in the resistivity are produced. Annealing effects were observed which we believe to be connected with the reconstitution of the superlattice structure.

  1. Interlaboratory comparison of radiation-induced attenuation in optical fibers

    International Nuclear Information System (INIS)

    A comparison of the losses induced in step index multimode, graded index multimode and single mode fibers by pulsed radiation exposure has been made among 12 laboratories over a period of 5 years. The recoveries of the incremental attenuations from 10-9 to 101 s are reported. Although a standard set of measurement parameters was attempted, differences between the laboratories are evident; possible origins for these are discussed. 18 refs., 18 figs., 7 tabs

  2. Curcumin Attenuates Methotrexate-Induced Hepatic Oxidative Damage in Rats

    International Nuclear Information System (INIS)

    In the present study, we have addressed the ability of curcumin to suppress MTX-induced liver damage. Hepatotoxicity was induced by injection of a single dose of MTX (20 mg/kg I.P.). MTX challenge induced liver damage that was well characterized histopathologically and biochemically. MTX increased relative liver/body weight ratio. Histologically, MTX produced fatty changes in hepatocytes and sinusoidal lining cells, mild necrosis and inflammation. Biochemically, the test battery entailed elevated activities of serum ALT and AST. Liver activities of superoxide dismutase (SOD), catalase (CAT) and level of reduced glutathione (GSH), were notably reduced, while lipid peroxidation, expressed as malondialdhyde (MDA) level was significantly increased. Administration of curcumin (100mg/kg, I.P.) once daily for 5 consecutive days after MTX challenge mitigated the injurious effects of MTX and ameliorated all the altered biochemical parameters. These results showed that administration of curcumin decreases MTX-induced liver damage probably via regulation of oxidant/anti-oxidant balance. In conclusion, the present study indicates that curcumin may be of therapeutic benefit against MTX-cytotoxicity.

  3. Attenuation of thermal radiative heat fluxes by water curtain

    International Nuclear Information System (INIS)

    On offshore oil and gas platforms, thermal or infra-red radiation emitted from hydrocarbon flares can have serious consequences on the safety and integrity of both personnel and equipment. At the temperatures of emission (∼ 1600 K), water is an excellent absorber of infra-red radiation, and this study investigates the potential for using a 'curtain' formed from a water spray to attenuate incident thermal radiation. A relatively simple model is devised to estimate the attenuation characteristics of a continuous layer of water, with further modification for the case of a spray It is found that a 120 deg. fog nozzle with an exit radius of r0 = 10 mm, supplied with 600 litres/minute of water at 3.5 bar, will provide adequate (down to a level of 1.9 kW/m2) attenuation for flame temperatures up to 2400 K. The dynamics of sprays are extremely complex and the current model does not consider interactions between aerodynamic drag, heat transfer, shape, size and distribution of droplets or surface tension effects. There appears to be potential for further refinement of the model, but this requires in-situ measurements. (author)

  4. Radiation damage in non-metals

    International Nuclear Information System (INIS)

    Work on the problem of radiation damage in non-metals over the past 25 years is reviewed with especial emphasis on the contribution made at AERE, Harwell and in particular by members of the Theoretical Physics Division. In the years between 1954 and the end of the 1960's the main thrust in the radiation damage of non-metals was model-building including devising defect models and mechanisms that were qualitatively acceptable, and compiling systematic data. The early 1970's made greater quantitative demands as computer techniques made theory more powerful. In many cases it was possible to predict defect properties accurately, so that one could distinguish between different defect models which were hard to tell apart by experiment alone. In the late 1970's the most important aspect has moved towards mechanisms of defect processes, especially in cases where experiment by itself is limited by timescale, by complexity, by the unintentional impurities inevitable in real crystals, or by the extreme conditions required. (UK)

  5. Investigation of solar cell radiation damage

    International Nuclear Information System (INIS)

    Development of communications satellites has led to the requirement for a greater and longer lived solar cell power source. Accordingly, studies have been undertaken with the aim of determining which solar cell array provides the greatest power at end of life and the amount of degradation. Investigation of the damage done to thin silicon and thin film CdS solar cells is being carried out in two steps. First, irradiations were performed singly with 0.15, 1.0 and 2.0MeV electrons and 0.7, 2.5 and 22MeV proton. Solar cells and their cover materials were irradiated separately in order to locate the sites of the damage. Diffusion length and I.V. characteristics of the cells and transmission properties of the cover materials were measured. All neasurements were made in vacuum immediately after irradiation. In the second part it is intended to study the effect of various combinations of proton, electron and photon irradiation both with and without an electrical load. The results of this part show whether synergism is involved in solar cell damage and the relative importance of each of three radiation sources if synergism is found

  6. Radiation damage to DNA-binding proteins

    International Nuclear Information System (INIS)

    The DNA-binding properties of proteins are strongly affected upon irradiation. The tetrameric lactose repressor (a dimer of dimers) losses its ability to bind operator DNA as soon as at least two damages per protomer of each dimer occur. The monomeric MC1 protein losses its ability to bind DNA in two steps : i) at low doses only the specific binding is abolished, whereas the non-specific one is still possible; ii) at high doses all binding vanishes. Moreover, the DNA bending induced by MC1 binding is less pronounced for a protein that underwent the low dose irradiation. When the entire DNA-protein complexes are irradiated, the observed disruption of the complexes is mainly due to the damage of the proteins and not to that of DNA. The doses necessary for complex disruption are higher than those inactivating the free protein. This difference, larger for MC1 than for lactose repressor, is due to the protection of the protein by the bound DNA. The oxidation of the protein side chains that are accessible to the radiation-induced hydroxyl radicals seems to represent the inactivating damage

  7. Radiation damage in zircon and monazite

    International Nuclear Information System (INIS)

    Monazite and zircon respond differently to ion irradiation and to thermal and irradiation-enhanced annealing. The damage process (i.e., elastic interactions leading to amorphization) in radioactive minerals (metamictization) is basically the same as for the ion-beam-irradiated samples with the exception of the dose rate which is much lower in the case of natural samples. The crystalline-to-metamict transition in natural samples with different degrees of damage, from almost fully crystalline to completely metamict, is compared to the sequence of microstructures observed for ion-beam-irradiated monazite and zircon. The damage accumulation process, representing the competing effects of radiation-induced structural disorder and subsequent annealing mechanisms (irradiation-enhanced and thermal) occurs at much higher temperatures for zircon than for monazite. The amorphization dose, expressed as displacements per atom, is considerably higher in the natural samples, and the atomic-scale process leading to metamictization appears to develop differently. Ion-beam-induced amorphization data were used to calculate the α-decay-event dose required for amorphization in terms of a critical radionuclide concentration, i.e., the concentration above which a sample of a given age will become metamict at a specific temperature. This equation was applied to estimate the reliability of U-Pb ages, to provide a qualitative estimate of the thermal history of high-U natural zircons, and to predict whether actinide-bearing zircon or monazite nuclear waste forms will become amorphous (metamict) over long timescales

  8. Combined inhibition of TGFβ and PDGF signaling attenuates radiation-induced pulmonary fibrosis

    Science.gov (United States)

    Dadrich, Monika; Nicolay, Nils H.; Flechsig, Paul; Bickelhaupt, Sebastian; Hoeltgen, Line; Roeder, Falk; Hauser, Kai; Tietz, Alexandra; Jenne, Jürgen; Lopez, Ramon; Roehrich, Manuel; Wirkner, Ute; Lahn, Michael; Huber, Peter E.

    2016-01-01

    ABSTRACT Background: Radiotherapy (RT) is a mainstay for the treatment of lung cancer, but the effective dose is often limited by the development of radiation-induced pneumonitis and pulmonary fibrosis. Transforming growth factor β (TGFβ) and platelet-derived growth factor (PDGF) play crucial roles in the development of these diseases, but the effects of dual growth factor inhibition on pulmonary fibrosis development remain unclear. Methods: C57BL/6 mice were treated with 20 Gy to the thorax to induce pulmonary fibrosis. PDGF receptor inhibitors SU9518 and SU14816 (imatinib) and TGFβ receptor inhibitor galunisertib were applied individually or in combinations after RT. Lung density and septal fibrosis were measured by high-resolution CT and MRI. Lung histology and gene expression analyses were performed and Osteopontin levels were studied. Results: Treatment with SU9518, SU14816 or galunisertib individually attenuated radiation-induced pulmonary inflammation and fibrosis and decreased radiological and histological signs of lung damage. Combining PDGF and TGFβ inhibitors showed to be feasible and safe in a mouse model, and dual inhibition significantly attenuated radiation-induced lung damage and extended mouse survival compared to blockage of either pathway alone. Gene expression analysis of irradiated lung tissue showed upregulation of PDGF and TGFβ-dependent signaling components by thoracic irradiation, and upregulation patterns show crosstalk between downstream mediators of the PDGF and TGFβ pathways. Conclusion: Combined small-molecule inhibition of PDGF and TGFβ signaling is a safe and effective treatment for radiation-induced pulmonary inflammation and fibrosis in mice and may offer a novel approach for treatment of fibrotic lung diseases in humans. Translational statement: RT is an effective treatment modality for cancer with limitations due to acute and chronic toxicities, where TGFβ and PDGF play a key role. Here, we show that a combined

  9. Stochastic modeling of p53-regulated apoptosis upon radiation damage

    CERN Document Server

    Bhatt, Divesh; Bahar, Ivet

    2011-01-01

    We develop and study the evolution of a model of radiation induced apoptosis in cells using stochastic simulations, and identified key protein targets for effective mitigation of radiation damage. We identified several key proteins associated with cellular apoptosis using an extensive literature survey. In particular, we focus on the p53 transcription dependent and p53 transcription independent pathways for mitochondrial apoptosis. Our model reproduces known p53 oscillations following radiation damage. The key, experimentally testable hypotheses that we generate are - inhibition of PUMA is an effective strategy for mitigation of radiation damage if the treatment is administered immediately, at later stages following radiation damage, inhibition of tBid is more effective.

  10. Thermal Decomposition of Radiation-Damaged Polystyrene

    International Nuclear Information System (INIS)

    The radiation-damaged polystyrene material (''polycube'') used in this study was synthesized by mixing a high-density polystyrene (''Dylene Fines No. 100'') with plutonium and uranium oxides. The polycubes were used on the Hanford Site in the 1960s for criticality studies to determine the hydrogen-to-fissile atom ratios for neutron moderation during processing of spent nuclear fuel. Upon completion of the studies, two methods were developed to reclaim the transuranic (TRU) oxides from the polymer matrix: (1) burning the polycubes in air at 873 K; and (2) heating the polycubes in the absence of oxygen and scrubbing the released monomer and other volatile organics using carbon tetrachloride. Neither of these methods was satisfactory in separating the TRU oxides from the polystyrene. Consequently, the remaining polycubes were sent to the Hanford Plutonium Finishing Plant (PFP) for storage. Over time, the high dose of alpha and gamma radiation has resulted in a polystyrene matrix that is highly cross-linked and hydrogen deficient and a stabilization process is being developed in support of Defense Nuclear Facility Safety Board Recommendation 94-1. Baseline processes involve thermal treatment to pyrolyze the polycubes in a furnace to decompose the polystyrene and separate out the TRU oxides. Thermal decomposition products from this degraded polystyrene matrix were characterized by Pacific Northwest National Laboratory to provide information for determining the environmental impact of the process and for optimizing the process parameters. A gas chromatography/mass spectrometry (GC/MS) system coupled to a horizontal tube furnace was used for the characterization studies. The decomposition studies were performed both in air and helium atmospheres at 773 K, the planned processing temperature. The volatile and semi-volatile organic products identified for the radiation-damaged polystyrene were different from those observed for virgin polystyrene. The differences were in the

  11. Thermal Decomposition of Radiation-Damaged Polystyrene

    Energy Technology Data Exchange (ETDEWEB)

    J Abrefah GS Klinger

    2000-09-26

    The radiation-damaged polystyrene material (''polycube'') used in this study was synthesized by mixing a high-density polystyrene (''Dylene Fines No. 100'') with plutonium and uranium oxides. The polycubes were used on the Hanford Site in the 1960s for criticality studies to determine the hydrogen-to-fissile atom ratios for neutron moderation during processing of spent nuclear fuel. Upon completion of the studies, two methods were developed to reclaim the transuranic (TRU) oxides from the polymer matrix: (1) burning the polycubes in air at 873 K; and (2) heating the polycubes in the absence of oxygen and scrubbing the released monomer and other volatile organics using carbon tetrachloride. Neither of these methods was satisfactory in separating the TRU oxides from the polystyrene. Consequently, the remaining polycubes were sent to the Hanford Plutonium Finishing Plant (PFP) for storage. Over time, the high dose of alpha and gamma radiation has resulted in a polystyrene matrix that is highly cross-linked and hydrogen deficient and a stabilization process is being developed in support of Defense Nuclear Facility Safety Board Recommendation 94-1. Baseline processes involve thermal treatment to pyrolyze the polycubes in a furnace to decompose the polystyrene and separate out the TRU oxides. Thermal decomposition products from this degraded polystyrene matrix were characterized by Pacific Northwest National Laboratory to provide information for determining the environmental impact of the process and for optimizing the process parameters. A gas chromatography/mass spectrometry (GC/MS) system coupled to a horizontal tube furnace was used for the characterization studies. The decomposition studies were performed both in air and helium atmospheres at 773 K, the planned processing temperature. The volatile and semi-volatile organic products identified for the radiation-damaged polystyrene were different from those observed for virgin

  12. Treadmill Exercise Preconditioning Attenuates Lung Damage Caused by Systemic Endotoxemia in Type 1 Diabetic Rats

    OpenAIRE

    Ching-Hsia Hung; Jann-Inn Tzeng; Che-Ning Chang; Yu-Wen Chen; Chia-Ying Cho; Jhi-Joung Wang

    2013-01-01

    Endotoxemia induces a series of inflammatory responses that may result in lung injury. However, heat shock protein72 (HSP72) has the potential to protect the lungs from damage. The objective of this study was to determine whether prior exercise conditioning could increase the expression of HSP72 in the lungs and attenuate lung damage in diabetic rats receiving lipopolysaccharide (LPS). Streptozotocin was used to induce diabetes in adult male Wistar rats. Rats were randomly assigned to sedenta...

  13. Amifostine (WR2721) Drug Controls Radiation Induced Damage in Rats

    International Nuclear Information System (INIS)

    Amifostine is a pro-drug in which selectivity is largely determined by the preferential formation and uptake of its cytoprotective metabolite, WR-1065, in normal tissues as a result of differences in membrane-bound alkaline phosphatase activity. Animals were categorized into four groups as follows: control group, WR-2721-intraperitoneally injected group at a dose of 100 mg/ kg, 1.5 Gy gamma-irradiated groups for 5 days (day post day) receiving final dose up to 7.5 Gy and WR-2721 injected group at 30 minutes before exposing to every fractionated dose of gamma-irradiation. Animals were sacrificed after 7 and 16 days after the final exposure to gamma-irradiation. The results obtained showed increased levels of plasma creatinine, plasma urea, plasma total protein, alanine and aspartate aminotransferases (ALT and AST), alkaline phosphatase (ALP), total bilirubin and gamma glutamyle transferase (gamma GT) and decreased levels of Albumin/ Globulin ratio (NG) in irradiated animal group compared with the control one. Administration of Amifostine before radiation exposure has significantly improved the radiation-induced changes in all these tested parameters. It could be concluded that application of Amifostine may minimize radiation damage and attenuate the side effects resulted from radiotherapy exposure

  14. Eugenol attenuates pulmonary damage induced by diesel exhaust particles.

    Science.gov (United States)

    Zin, Walter A; Silva, Ana G L S; Magalhães, Clarissa B; Carvalho, Giovanna M C; Riva, Douglas R; Lima, Crystianne C; Leal-Cardoso, Jose H; Takiya, Christina M; Valença, Samuel S; Saldiva, Paulo H N; Faffe, Débora S

    2012-03-01

    Environmentally relevant doses of inhaled diesel particles elicit pulmonary inflammation and impair lung mechanics. Eugenol, a methoxyphenol component of clove oil, presents in vitro and in vivo anti-inflammatory and antioxidant properties. Our aim was to examine a possible protective role of eugenol against lung injuries induced by diesel particles. Male BALB/c mice were divided into four groups. Mice received saline (10 μl in; CTRL group) or 15 μg of diesel particles DEP (15 μg in; DIE and DEUG groups). After 1 h, mice received saline (10 μl; CTRL and DIE groups) or eugenol (164 mg/kg; EUG and DEUG group) by gavage. Twenty-four hours after gavage, pulmonary resistive (ΔP1), viscoelastic (ΔP2) and total (ΔPtot) pressures, static elastance (Est), and viscoelastic component of elastance (ΔE) were measured. We also determined the fraction areas of normal and collapsed alveoli, amounts of polymorpho- (PMN) and mononuclear cells in lung parenchyma, apoptosis, and oxidative stress. Est, ΔP2, ΔPtot, and ΔE were significantly higher in the DIE than in the other groups. DIE also showed significantly more PMN, airspace collapse, and apoptosis than the other groups. However, no beneficial effect on lipid peroxidation was observed in DEUG group. In conclusion, eugenol avoided changes in lung mechanics, pulmonary inflammation, and alveolar collapse elicited by diesel particles. It attenuated the activation signal of caspase-3 by DEP, but apoptosis evaluated by TUNEL was avoided. Finally, it could not avoid oxidative stress as indicated by malondialdehyde. PMID:22194320

  15. Computer simulations of radiation damage in protein crystals

    International Nuclear Information System (INIS)

    The achievable resolution and the quality of the dataset of an intensity data collection for structure analysis of protein crystals with X-rays is limited among other factors by radiation damage. The aim of this work is to obtain a better quantitative understanding of the radiation damage process in proteins. Since radiation damage is unavoidable it was intended to look for the optimum ratio between elastically scattered intensity and radiation damage. Using a Monte Carlo algorithm physical processes after an inelastic photon interaction are studied. The main radiation damage consists of ionizations of the atoms through the electron cascade following any inelastic photon interaction. Results of the method introduced in this investigation and results of an earlier theoretical studies of the influence of Auger-electron transport in diamond are in a good agreement. The dependence of the radiation damage as a function of the energy of the incident photon was studied by computer-aided simulations. The optimum energy range for diffraction experiments on the protein myoglobin is 10-40 keV. Studies of radiation damage as a function of crystal volume and shape revealed that very small plate or rod shaped crystals suffer less damage than crystals formed like a cube with the same volume. Furthermore the influence of a few heavy atoms in the protein molecule on radiation damage was examined. Already two iron atoms in the unit cell of myoglobin increase radiation damage significantly. (orig.)

  16. Coniferyl aldehyde attenuates radiation enteropathy by inhibiting cell death and promoting endothelial cell function.

    Directory of Open Access Journals (Sweden)

    Ye-Ji Jeong

    Full Text Available Radiation enteropathy is a common complication in cancer patients. The aim of this study was to investigate whether radiation-induced intestinal injury could be alleviated by coniferyl aldehyde (CA, an HSF1-inducing agent that increases cellular HSP70 expression. We systemically administered CA to mice with radiation enteropathy following abdominal irradiation (IR to demonstrate the protective effects of CA against radiation-induced gastrointestinal injury. CA clearly alleviated acute radiation-induced intestinal damage, as reflected by the histopathological data and it also attenuated sub-acute enteritis. CA prevented intestinal crypt cell death and protected the microvasculature in the lamina propria during the acute and sub-acute phases of damage. CA induced HSF1 and HSP70 expression in both intestinal epithelial cells and endothelial cells in vitro. Additionally, CA protected against not only the apoptotic cell death of both endothelial and epithelial cells but also the loss of endothelial cell function following IR, indicating that CA has beneficial effects on the intestine. Our results provide novel insight into the effects of CA and suggest its role as a therapeutic candidate for radiation-induced enteropathy due to its ability to promote rapid re-proliferation of the intestinal epithelium by the synergic effects of the inhibition of cell death and the promotion of endothelial cell function.

  17. Radiation Damage In Reactor Cavity Concrete

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G [ORNL; Le Pape, Yann [ORNL; Naus, Dan J [ORNL; Remec, Igor [ORNL; Busby, Jeremy T [ORNL; Rosseel, Thomas M [ORNL; Wall, Dr. James Joseph [Electric Power Research Institute (EPRI)

    2015-01-01

    License renewal up to 60 years and the possibility of subsequent license renewal to 80 years has established a renewed focus on long-term aging of nuclear generating stations materials, and recently, on concrete. Large irreplaceable sections of most nuclear generating stations include concrete. The Expanded Materials Degradation Analysis (EMDA), jointly performed by the Department of Energy, the Nuclear Regulatory Commission and Industry, identified the urgent need to develop a consistent knowledge base on irradiation effects in concrete. Much of the historical mechanical performance data of irradiated concrete does not accurately reflect typical radiation conditions in NPPs or conditions out to 60 or 80 years of radiation exposure. To address these potential gaps in the knowledge base, The Electric Power Research Institute and Oak Ridge National Laboratory are working to disposition radiation damage as a degradation mechanism. This paper outlines the research program within this pathway including: (i) defining the upper bound of the neutron and gamma dose levels expected in the biological shield concrete for extended operation (80 years of operation and beyond), (ii) determining the effects of neutron and gamma irradiation as well as extended time at temperature on concrete, (iii) evaluating opportunities to irradiate prototypical concrete under accelerated neutron and gamma dose levels to establish a conservative bound and share data obtained from different flux, temperature, and fluence levels, (iv) evaluating opportunities to harvest and test irradiated concrete from international NPPs, (v) developing cooperative test programs to improve confidence in the results from the various concretes and research reactors, (vi) furthering the understanding of the effects of radiation on concrete (see companion paper) and (vii) establishing an international collaborative research and information exchange effort to leverage capabilities and knowledge.

  18. Incretin attenuates diabetes-induced damage in rat cardiac tissue.

    Science.gov (United States)

    AbdElmonem Elbassuoni, Eman

    2014-09-01

    Glucagon-like peptide-1 (GLP-1), as a member of the incretin family, has a role in glucose homeostasis, its receptors distributed throughout the body, including the heart. The aim was to investigate cardiac lesions following diabetes induction, and the potential effect of GLP-1 on this type of lesions and the molecular mechanism driving this activity. Adult male rats were classified into: normal, diabetic, 4-week high-dose exenatide-treated diabetic rats, 4-week low-dose exenatide-treated diabetic rats, and 1-week exenatide-treated diabetic rats. The following parameters were measured: in blood: glucose, insulin, lactate dehydrogenase (LDH), total creatine kinase (CK), creatine kinase MB isoenzyme (CK-MB), and CK-MB relative index; in cardiac tissue: lipid peroxide (LPO) and some antioxidant enzymes. The untreated diabetic group displayed significant increases in blood level of glucose, LDH, and CK-MB, and cardiac tissue LPO, and a significant decrease in cardiac tissue antioxidant enzymes. GLP-1 supplementation in diabetic rats definitely decreased the hyperglycemia and abolished the detrimental effects of diabetes on the cardiac tissue. The effect of GLP-1 on blood glucose and on the heart also appeared after a short supplementation period (1 week). It can be concluded that GLP-1 has beneficial effects on diabetes-induced oxidative cardiac tissue damage, most probably via its antioxidant effect directly acting on cardiac tissue and independent of its hypoglycemic effect. PMID:25011640

  19. Compilation of radiation damage test data. II

    International Nuclear Information System (INIS)

    This report summarizes radiation damage test data on thermosetting and thermoplastic resins, with the main emphasis on epoxy resins used for magnet coil insulations. Also, other materials such as polyesters, phenolics, polyurethanes, silicones, etc., are represented. The materials have been irradiated in a nuclear reactor to integrated absorbed doses between 5x106 Gy and 1x108 Gy. The mechanical properties, e.g. the flexural strength, deflection at break, and tangent modulus of elasticity, have been measured on irradiated and non-irradiated samples. The results are given as variation of these parameters versus absorbed dose and are presented in the form of tables and graphs. The tested materials are catalogued in alphabetical order. (Auth.)

  20. Protection of DNA damage by radiation exposure

    International Nuclear Information System (INIS)

    The SOS response of Escherichia coli is positively regulated by RecA. To examine the effects of polyamines on The SOS response of E. Coli, we investigated the expression of recA gene in polyamine-deficient mutant and wild type carrying recA'::lacZ fusion gene. As a result, recA expression by mitomycin C is higher in wild type than that of polyamine-deficient mutant, but recA expression by UV radiation is higher in wild type than of mutant. We also found that exogenous polyamines restored the recA expression in the polyamine-deficient mutant to the wild type level. These results proposed that polyamines play an important role in mechanism of intracellular DNA protection by DNA damaging agents

  1. Protection of DNA damage by radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Ho; Kim, In Gyu; Lee, Kang Suk; Kim, Kug Chan; Oh, Tae Jung

    1998-12-01

    The SOS response of Escherichia coli is positively regulated by RecA. To examine the effects of polyamines on The SOS response of E. Coli, we investigated the expression of recA gene in polyamine-deficient mutant and wild type carrying recA'::lacZ fusion gene. As a result, recA expression by mitomycin C is higher in wild type than that of polyamine-deficient mutant, but recA expression by UV radiation is higher in wild type than of mutant. We also found that exogenous polyamines restored the recA expression in the polyamine-deficient mutant to the wild type level. These results proposed that polyamines play an important role in mechanism of intracellular DNA protection by DNA damaging agents.

  2. Compilation of radiation damage test data

    International Nuclear Information System (INIS)

    This report summarizes radiation damage test data on commercially available organic cable insulation and jacket materials: Ethylene-propylene rubbers, polyethylenes, polyurethanes, silicone rubbers, and copolymers based on polyethylene. The materials have been irradiated either in a nuclear reactor, or with a cobalt-60 source, or in the CERN accelerators, at different dose rates. The absorbed doses were between 103 and 5x106 Gy. Mechanical properties, e.g. tensile strength, elongation at break, and hardness, have been tested on irradiated and non-irradiated samples, according to the recommendations of the International Electrotechnical Commission. The results are presented in the form of tables and graphs to show the effect of the absorbed dose on the measured properties. (orig.)

  3. Synergistic damage by UVA radiation and pollutants.

    Science.gov (United States)

    Burke, K E; Wei, H

    2009-01-01

    Not only is skin cancer by far the most common human cancer but also the incidence of skin cancer has been increasing at an alarming rate in recent decades. Fortunately, most people now realize that sun exposure causes unattractive photoaging and skin cancer, so they do apply sunscreens conscientiously. However, until recently, most sunscreens did not adequately protect against ultraviolet A (UVA) radiation. Although UVA is indeed less erythrogenic and less carcinogenic than UVB, UVA directly causes photoaging and enhances UVB-induced skin cancer. Furthermore, recent research demonstrates that UVA combined with environmental pollutants (including cigarette smoke) significantly increases the risk of skin cancer. Similarly, previous research demonstrated another synergy between environmental pollutants and UV: When ozone exposure precedes UV exposure, there is enhancement of UV-induced depletion of protective vitamin E from the skin's stratum corneum. This article reviews experimental evidence that environmental pollutants (such as benzo[a]pyrene (BaP), a commonly used index of environmental pollution) are photosensitizers that generate reactive oxygen species (ROS) when exposed to UVA radiation. This in turn causes oxidative and genetic damage, leading to unattractive photodamage and carcinogenesis. PMID:19651790

  4. Omega-3 Polyunsaturated Fatty Acids Attenuate Radiation-induced Oxidative Stress and Organ Dysfunctions in Rats

    International Nuclear Information System (INIS)

    The Aim of the present study was to determine the possible protective effect of omega-3 polyunsaturated fatty acids (omega-3 PUFA) against radiation-induced oxidative stress associated with organ dysfunctions. Omega-3 PUFA was administered by oral gavages to male albino rats at a dose of 0.4 g/ kg body wt daily for 4 weeks before whole body γ-irradiation with 4Gy. Significant increase of serum lipid peroxidation end product as malondialdehyde (MDA) along with the reduction in blood glutathione (GSH) content, superoxide dismutase (SOD) and glutathione peroxidase (GPX) enzyme activities were recorded on 3rd and 8th days post-irradiation. Oxidative stress was associated with a significant increase in lactate dehydrogenase (LDH) and creatine phosphokinase (CPK) enzyme activities, markers of heart damage, significant increases in uric acid, urea and creatinine levels, markers of kidney damage, significant increases of alkaline phosphatase (ALP) and transaminases (ALT and AST) activities, markers of liver damage. Moreover significant increases in total cholesterol and triglycerides levels were recorded. Omega-3 PUFA administration pre-irradiation significantly attenuated the radiation-induced oxidative stress and organ dysfunctions tested in this study. It could be concluded that oral supplementation of omega-3 PUFA before irradiation may afford protection against radiation-induced oxidative stress and might preserve the integrity of tissue functions of the organs under investigations.

  5. Constructive and critical approach of the radiation damage simulation

    International Nuclear Information System (INIS)

    This work deals with the problem of radiation damage in materials for applications in development of fission and nuclear fusion technologies. It is organised in 3 sections. In section 1 are presented the mechanisms of formation and the evolution kinetics of the primary damage. Section 2 is devoted to the study of the sensitivity of the radiation damage at different approximations. Section 3 discusses the contribution of the ab initio calculations to the study of radiation damage and more particularly the point defects in a dilute Fe-Cu ferritic alloy. This work is illustrated by several publications added in each section. (O.M.)

  6. Radiation damage to DNA: the effect of LET

    Energy Technology Data Exchange (ETDEWEB)

    Ward, J.F.; Milligan, J.R. [California Univ., San Diego, La Jolla, CA (United States). School of Medicine

    1997-03-01

    Mechanisms whereby ionizing radiation induced damage are introduced into cellular DNA are discussed. The types of lesions induced are summarized and the rationale is presented which supports the statement that radiation induced singly damaged sites are biologically unimportant. The conclusion that multiply damaged sites are critical is discussed and the mechanisms whereby such lesions are formed are presented. Structures of multiply damaged sites are summarized and problems which they present to cellular repair systems are discussed. Lastly the effects of linear energy transfer on the complexity of multiply damaged sites are surveyed and the consequences of this increased complexity are considered in terms of cell survival and mutation. (author)

  7. Radiation-induced DNA damage and DNA repair

    International Nuclear Information System (INIS)

    Although DNA undergoes various types of damage from radiation, active oxygen, and the like, a living body has a plurality of DNA repair mechanisms responding to the types of DNA damage. On the other hand, there are a system that results in cell death if the repair is impossible and a mechanism to lead to concretization if further repair is not accurately made. This paper explains the following items as the basic researches on these types of DNA damage and the repair mechanisms: (1) biological effects of DNA damage, (2) effect of DNA damage on DNA synthesis, and (3) effects of DNA damage on cells. It also explains the effects of radiation on cells with a focus on specific mechanism for (1) DNA damage caused by direct action due to radiation and by indirect action due mainly to active oxygen, and (2) DNA repair mechanism that works on DNA double-strand break (DSB). (A.O.)

  8. Radiation damage in a high Ni weld

    International Nuclear Information System (INIS)

    WWER-1000 RPV weld metals are characterized by a high content of nickel, mostly about 1.7 mass % with content of manganese around 0.8 mass % with a very low copper content - about 0.05 mass %. In such material some late blooming phase effect should be observed during irradiation. Such typical weld material was irradiated in the experimental reactor LVR-15 in N RI Rez at the irradiation temperature 290 C degrees and at five neutron fluences from 1.5 to 9.5 *1023 m-2 (E>1 MeV). Charpy V-notch impact tests, static fracture toughness tests, tensile and hardness measurement were performed to obtain effect of neutron fluence on radiation hardening as well as embrittlement. Neutron fluence dependences of all these property changes have monotonic character but with a high neutron embrittlement exponent around 0.8. Scanning electron microscope of fracture surfaces showed no or very small portion of intercrystalline fracture. Transmission electron microscopy was performed on specimens from all neutron fluences. Only low density of black-dot damage has been observed. It is assumed that most of defect are dislocation loops. The late blooming phase which may be observed from results of mechanical properties are probably below the resolution of the used JEM-2010, i.e. 1.5 nm. (authors)

  9. Electronic effects in radiation damage simulations

    International Nuclear Information System (INIS)

    A methodology for including electronic effects in classical radiation damage simulations is presented. The method is used to calculate the number of residual defects for low energy (10 keV) cascades in Fe, as a function of the electron-phonon coupling strength. It was found that strong electron-phonon coupling reduced the number of residual defects by rapidly removing energy from the cascade and reducing the thermal spike. Intermediate coupling increased the number of defects by quenching the thermal spike and reducing defect recombination. Thermostatting the cascade with the local, time dependent electronic temperature, rather than the ambient temperature, reduced the number of residual defects by enhancing defect recombination. Swift heavy ion irradiation in tungsten was modeled using the same methodology. In this case we found that the number of residual defects created by a given electronic stopping power was strongly dependent on the temperature variation of the electronic heat capacity. In contrast to cascade simulations, the interstitials were located closer to the core of the ion track than the vacancies.

  10. Chemistry of radiation damage to wire chambers

    International Nuclear Information System (INIS)

    Proportional counters are used to study aspects of radiation damage to wire chambers (wire aging). Principles of low-pressure, rf plasma chemistry are used to predict the plasma chemistry in electron avalanches (1 atm, dc). (1) Aging is studied in CF4/iC4H10 gas mixtures. Wire deposits are analyzed by Auger electron spectroscopy. An apparent cathode aging process resulting in loss of gain rather than in a self-sustained current is observed in CF4-rich gases. A four-part model considering plasma polymerization of the hydrocarbon, etching of wire deposits by CF4, acceleration of deposition processes in strongly etching environments, and reactivity of the wire surface is developed to understand anode wire aging in CF4/iC4H10 gases. Practical guidelines suggested by the model are discussed. (2) Data are presented to suggest that trace amounts of Freons do not affect aging rates in either dimethyl ether or Ar/C2H6. Apparent loss of gain is explained by attachment of primary electrons to a continuously increasing concentration of Freon 11 (CCl3F) in the counter gas. An increase in the concentration of Freon 11 in dimethyl ether is caused by a distillation process in the gas supply bottle and is a natural consequence of the unequal volatilities of the two compounds

  11. Radiation damage and its repair in non-sporulating bacteria

    International Nuclear Information System (INIS)

    A review is given of radiation damage and its repair in non-sporulating bacteria. The identification and measurement of radiation damage in the DNA of the bacteria after exposure to ultraviolet radiation and ionizing radiation is described. Measuring the extent of DNA repair and ways of isolating repair mutants are also described. The DNA repair mechanisms for UV-induced damage are discussed including photoreactivation repair, excision repair, post-replication recombination repair and induced error-prone repair. The DNA repair mechanisms for ionizing radiation damage are also discussed including the repair of both single and double-strand breaks. Other aspects discussed include the effects of growth, irradiation medium and recovery medium on survival, DNA repair in humans, the commercial use of UV and ionizing radiations and the future of ionizing irradiation as a food treatment process. (U.K.)

  12. Synchrotron microbeam x-ray radiation damage in semiconductor layers

    International Nuclear Information System (INIS)

    Radiation induced structural damage is observed in silicon-on-insulator (SOI) and SiGe on SOI samples illuminated with monochromatic (11.2 keV) x-ray microbeams approximately 250 nm in diameter. The x-ray diffraction peaks from the irradiated layers irreversibly degrade with time, indicating permanent structural damage to the crystal lattice. The size of the damaged regions is almost an order of magnitude larger than the beam size. The magnitude of damage decreases as one moves away from the center of the illuminated volume. We discuss the threshold dosage required for damage initiation and possible mechanisms for the observed damage

  13. Attenuation coefficient of usable solar radiation of the global oceans

    Science.gov (United States)

    Lin, Junfang; Lee, Zhongping; Ondrusek, Michael; Kahru, Mati

    2016-05-01

    Usable solar radiation (USR) represents spectrally integrated solar energy in the spectral range of 400-560 nm, a domain where photons penetrate the most in oceanic waters and thus contribute to photosynthesis and heating at deeper depths. Through purely numerical simulations, it was found that the diffuse attenuation coefficient of downwelling USR (Kd(USR), m-1) is nearly a constant vertically in the upper water column for clear waters and most turbid waters. Subsequently an empirical model was developed to estimate Kd(USR) based on the diffuse attenuation coefficient at 490 nm (Kd(490), m-1). We here evaluate this relationship using data collected from a wide range of oceanic and coastal environments and found that the relationship between Kd(490) and Kd(USR) developed via the numerical simulation is quite robust. We further refined this relationship to extend the applicability to "clearest" natural waters. This refined relationship was then used to produce sample distribution of Kd(USR) of global oceans. As expected, extremely low Kd(USR) (˜0.02 m-1) was observed in ocean gyres, while significantly higher Kd(USR) (˜5.2 m-1) was found in very turbid coastal regions. A useful application of Kd(USR) is to easily and accurately propagate surface USR to deeper depths, potentially to significantly improve the estimation of basin scale primary production and heat fluxes in the upper water column.

  14. Influence of radiation quality on the expression of chromosomal damage

    International Nuclear Information System (INIS)

    The amount of chromosomal damage induced in synchronous V79 cells by either 250 kV X-rays or 4.6 MeV/u Ar ions (LET: 1850 keV/μm) was determined at five successive sampling times. The experiments show that the time course of the appearance of damaged cells is strongly influenced by radiation-induced cell cycle perturbations and mitotic delay and depends on radiation quality and dose. The yield of chromosomal damage was found to increase with sampling time, but this increase was more pronounced for Ar ions. Because of the observed differences in the yield time profiles induced by sparsely and densely ionizing radiation the contribution of each sample to the overall damage was considered, i.e. the total (time integrated) amount of damage was determined. The obtained data are interpreted in terms of differences in the spatial energy deposition by sparsely and densely ionizing radiation. (author)

  15. Attenuation coefficients of 123 keV γ-radiation by dilute solutions of sodium chloride

    International Nuclear Information System (INIS)

    The linear attenuation and mass attenuation (or absorption) coefficients of the 123 keV γ radiation from 57Co by dilute solutions of NaCl were studied for varying concentrations. The mixture rule for the theoretical calculation of attenuation coefficients was developed for solutions. This study explores the validity of the expected exponential attenuation absorption law for γ-radiation in solutions and also provides an alternative method for the direct determination of linear and mass attenuation coefficients of soluble salts in solid form without obtaining them in pure crystalline form. (Author)

  16. UV Radiation Damage and Bacterial DNA Repair Systems

    Science.gov (United States)

    Zion, Michal; Guy, Daniel; Yarom, Ruth; Slesak, Michaela

    2006-01-01

    This paper reports on a simple hands-on laboratory procedure for high school students in studying both radiation damage and DNA repair systems in bacteria. The sensitivity to ultra-violet (UV) radiation of both "Escherichia coli" and "Serratia marcescens" is tested by radiating them for varying time periods. Two growth temperatures are used in…

  17. Toxicity attenuation of ophidian venoms by ionizing radiation

    International Nuclear Information System (INIS)

    A brief introduction about some species of Brazilian snakes, their habits and the treatment available is presented. A new immunization technique using gamma radiation is studied. Its described that irradiated toxins inoculated in mice does not cause any tissue damage (hemorrhage) at the intake region. It is observed that the irradiation detoxicate the venoms. The study intends to minimize the suffering of the animal which produces the serum as well as to increase the production of serums for use in domestic animals attacked by venomous snakes

  18. Radiation damage to nucleoprotein complexes in macromolecular crystallography

    Energy Technology Data Exchange (ETDEWEB)

    Bury, Charles; Garman, Elspeth F.; Ginn, Helen Mary [University of Oxford, South Parks Road, Oxford OX1 3QU (United Kingdom); Ravelli, Raimond B. G. [Maastricht University, PO Box 616, Maastricht 6200 MD (Netherlands); Carmichael, Ian [University of Notre Dame, Notre Dame, IN 46556 (United States); Kneale, Geoff; McGeehan, John E., E-mail: john.mcgeehan@port.ac.uk [University of Portsmouth, King Henry 1st Street, Portsmouth PO1 2DY (United Kingdom)

    2015-01-30

    Quantitative X-ray induced radiation damage studies employing a model protein–DNA complex revealed a striking partition of damage sites. The DNA component was observed to be far more resistant to specific damage compared with the protein. Significant progress has been made in macromolecular crystallography over recent years in both the understanding and mitigation of X-ray induced radiation damage when collecting diffraction data from crystalline proteins. In contrast, despite the large field that is productively engaged in the study of radiation chemistry of nucleic acids, particularly of DNA, there are currently very few X-ray crystallographic studies on radiation damage mechanisms in nucleic acids. Quantitative comparison of damage to protein and DNA crystals separately is challenging, but many of the issues are circumvented by studying pre-formed biological nucleoprotein complexes where direct comparison of each component can be made under the same controlled conditions. Here a model protein–DNA complex C.Esp1396I is employed to investigate specific damage mechanisms for protein and DNA in a biologically relevant complex over a large dose range (2.07–44.63 MGy). In order to allow a quantitative analysis of radiation damage sites from a complex series of macromolecular diffraction data, a computational method has been developed that is generally applicable to the field. Typical specific damage was observed for both the protein on particular amino acids and for the DNA on, for example, the cleavage of base-sugar N{sub 1}—C and sugar-phosphate C—O bonds. Strikingly the DNA component was determined to be far more resistant to specific damage than the protein for the investigated dose range. At low doses the protein was observed to be susceptible to radiation damage while the DNA was far more resistant, damage only being observed at significantly higher doses.

  19. Radiation damage for the spallation target of ADS

    International Nuclear Information System (INIS)

    By using SHIELD codes system, the authors investigate the radiation damage, such as radiation damage cross section, displacement atom cross section and the rate of displacement atom, gas production cross section, the rate of gas production and the ratio, R, of the helium and displacement production rates in target, container window and spallation neutron source materials as W and Pb induced from intermediate energy proton and neutron incident. And the study of radiation damage in the thick Pb target with long 60 cm, radius 20 cm is presented

  20. Radiation Damage to Artemia Cysts:Effects of Water Vapor.

    Science.gov (United States)

    Snipes, W C; Gordy, W

    1963-10-25

    Water vapor altered the form and greatly increased the rate of decay of the electron-spin resonance pattern of long-lived free radicals obtained upon gamma irradiation of Artemia salina cysts ( brine shrimp eggs). These results, combined with data on radiation survival, indicate that the water vapor protects the cysts from radiation damage, or heals the damage. They also indicate that water protects the cysts from the effect of oxygen by neutralizing the radiation-induced free radicals before they can interact with oxygen to produce irreversible damage. PMID:17748168

  1. Fundamental Technology Development for Radiation Damage in Nuclear Materials

    International Nuclear Information System (INIS)

    This project was performed to achieve technologies for the evaluation of radiation effects at materials irradiated at HANARO and nuclear power plants, to establish measurement equipment and software for the analysis of radiation defects and to set up facilities for the measurements of radiation damage with non-destructive methods. Major targets were 1) establishment of hot laboratories and remote handling facilities/ technologies for the radioactive material tests, 2) irradiation test for the simulation of nuclear power plant environment and measurement/calculation of physical radiation damage, 3) evaluation and analysis of nano-scale radiation damage, 4) evaluation of radiation embrittlement with ultrasonic resonance spectrum measurement and electromagnetic measurement and 5) basic research of radiation embrittlement and radiation damage mechanism. Through the performance of 3 years, preliminary basics were established for the application research to evaluation of irradiated materials of present nuclear power plants and GEN-IV systems. Particularly the results of SANS, PAS and TEM analyses were the first output in Korea. And computer simulations of radiation damage were tried for the first time in Korea. The technologies will be developed for the design of GEN-IV material

  2. Photobiological aspects of radiation damage to bacteria

    International Nuclear Information System (INIS)

    In this report, we, submit a critical analysis of experiments aimed to estimate the contribution of the processes of ionization and electron excitation to lethal and mutagenic effects of ionizing radiation. In discussing the phenomenon of photoreactivation after the effect of ionizing radiation, we arrived at a conclusion that the processes of electron excitation, initiated by either Vavilov-Cerenkov light or the direct reaction of radiation energy with the substance, play an important role in the biological effect of ionizing radiation

  3. Environmental damage valuation as radiation protection tool

    International Nuclear Information System (INIS)

    Environmental radiation protection procedures do not have global consensus. Aiming the development of consensus mechanisms to guide environmental radiation protection procedures, it appears that the approaches used by non-radioactive environmental protection are very promising. Among these approaches, environmental valuation procedures are commonly employed, and are very proper for environmental radiation protection. (author)

  4. Environmental damage valuation as radiation protection tool

    International Nuclear Information System (INIS)

    Environmental radiation protection procedures do not have global consensus. In researching mechanisms to guide environmental radiation protection procedures consensus searching, the approaches used by non-radioactive environmental protection are very promising. Among the approaches, environmental valuation procedures are commonly employed, and are very proper for environmental radiation protection. (author)

  5. Linear attenuation (or absorption) coefficient of gamma radiation for dilute solutions of potassium chloride

    International Nuclear Information System (INIS)

    The mass attenuation and energy absorption coefficients are basic quantities used in calculations of photon energy transport and deposition for radiation dosimetry. This report describes a study of the concentration dependence of the attenuation of γ radiation of various energies by KCl solutions of different concentration. (author)

  6. Influence of Detector Radiation Damage on CR Mammography Quality Control.

    Science.gov (United States)

    Moriwaki, Atsumi; Ishii, Mie; Terazono, Shiho; Arao, Keiko; Ishii, Rie; Sanada, Taizo; Yoshida, Akira

    2016-05-01

    Recently, radiation damage to the detector apparatus employed in computed radiography (CR) mammography has become problematic. The CR system and the imaging plate (IP) applied to quality control (QC) program were also used in clinical mammography in our hospital, and the IP to which radiation damage has occurred was used for approximately 5 years (approximately 13,000 exposures). We considered using previously acquired QC image data, which is stored in a server, to investigate the influence of radiation damage to an IP. The mammography unit employed in this study was a phase contrast mammography (PCM) Mermaid (KONICA MINOLTA) system. The QC image was made newly, and it was output in the film, and thereafter the optical density of the step-phantom image was measured. An input (digital value)-output (optical density) conversion curve was plotted using the obtained data. The digital values were then converted to optical density values using a reference optical density vs. digital value curve. When a high radiation dose was applied directly, radiation damage occurred at a position on the IP where no object was present. Daily QC for mammography is conducted using an American College of Radiology (ACR) accreditation phantom and acrylic disc, and an environmental background density measurement is performed as one of the management indexes. In this study, the radiation damage sustained by the acrylic disc was shown to differ from that of the background. Thus, it was revealed that QC results are influenced by radiation damage. PMID:27211088

  7. Radiation damage measurements in room-temperature semiconductor radiation detectors

    CERN Document Server

    Franks, L A; Olsen, R W; Walsh, D S; Vizkelethy, G; Trombka, J I; Doyle, B L; James, R B

    1999-01-01

    The literature of radiation damage measurements on cadmium zinc telluride (CZT), cadmium telluride (CT), and mercuric iodide (HgI sub 2) is reviewed and in the case of CZT supplemented by new alpha particle data. CZT strip detectors exposed to intermediate energy (1.3 MeV) proton fluences exhibit increased interstrip leakage after 10 sup 1 sup 0 p/cm sup 2 and significant bulk leakage after 10 sup 1 sup 2 p/cm sup 2. CZT exposed to 200 MeV protons shows a two-fold loss in energy resolution after a fluence of 5x10 sup 9 p/cm sup 2 in thick (3 mm) planar devices but little effect in 2 mm devices. No energy resolution effects were noted from a moderated fission spectrum of neutrons after fluences up to 10 sup 1 sup 0 n/cm sup 2 , although activation was evident. Exposures of CZT to 5 MeV alpha particles at fluences up to 1.5x10 sup 1 sup 0 alpha/cm sup 2 produced a near linear decrease in peak position with fluence and increases in FWHM beginning at about 7.5x10 sup 9 alpha/cm sup 2. CT detectors show resolution...

  8. Single Molecule Scanning of DNA Radiation Oxidative Damage Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal will develop an assay to map genomic DNA, at the single molecule level and in a nanodevice, for oxidative DNA damage arising from radiation exposure;...

  9. Radiation damage of the ILC positron source target

    Energy Technology Data Exchange (ETDEWEB)

    Ushakov, A.; Riemann, S.

    2007-11-15

    The radiation damage of the positron source target for the International Linear Collider (ILC) has been studied. The displacement damage in target material due to multi-MeV photons has been calculated by combining FLUKA simulations for secondary particle production, SPECTER data for neutron displacement cross-sections and the Lindhard model for estimations of displacement damage by ions. The radiation damage of a stationary Ti6Al4V target in units of displacements per atom (dpa) has been estimated for photons from an undulator with strength 0.92 and period 1.15 cm. The calculated damage is 7 dpa. Approximately 12.5% of displacement damage result from neutrons. (orig.)

  10. UV-type damage associated with ionizing radiation: a review

    International Nuclear Information System (INIS)

    The induction of UV-type damage by ionizing radiation in repair deficient strains of E. coli is reviewed. Both photoreactivable and non-photoreactivable types of damage can be observed. The induction of UV-type damage is largely independent of the presence of free-radical reactive agents (e.g. oxygen and thiols), but is dependent upon the energy of the photon-or electron-beam used, the radiation geometry and the optical absorbance of the extracellular medium. On the basis of calculations and experimental evidence, it is clear that one mechanism whereby such damage arises is through the generation of Cerenkov emission. However, small yields of UV-type damage can be produced using X-rays whose energy is below the threshold for production of Cerenkov emission. In this instance, the damage induction mechanism is thought to involve a direct excitation process. (author)

  11. Attenuation of internal organ damages by exogenously administered epidermal growth factor (EGF) in burned rodents.

    Science.gov (United States)

    Berlanga, Jorge; Lodos, Jorge; López-Saura, Pedro

    2002-08-01

    Major burns are associated with multiple internal organ damages, including necrosis of the gastrointestinal mucosa. Failure of the intestinal barrier is a serious complication in burned patients. Epidermal growth factor (EGF) is a mitogenic polypeptide that stimulates wound repair and affords protection to the gastric mucosa. We examined whether a single systemic intervention with EGF prevents organ systems damages, following full-thickness scalds (25-30%) in rodents. Animals were randomly assigned to receive an intraperitoneal injection of EGF (30 microg/kg in mice, 10 microg/kg in rats) or saline solution, 30 min prior thermal injury in mice or after the cutaneous injury in rats. General clinical condition and mortality during 24h were recorded. Animals were autopsied and histopathological and histomorphometric studies were conducted. Mice treated with EGF exhibited a milder clinical evolution and acute lethality was significantly reduced as compared to saline counterparts (P<0.01). Histopathological and morphometric analysis showed that EGF significantly reduced intestinal necrosis and contributed to preserve jejunoileal architecture in mice (P<0.05) and rats (P<0.01). The onset of renal hemorrhagic foci was significantly reduced in EGF-treated groups (P<0.01). Lung damages appeared attenuated in EGF-treated animals. These data indicate the salutary effects of EGF by attenuating internal complications associated to thermal injuries. Further studies are warranted to fully elucidate the usefulness of this therapy. PMID:12163282

  12. Curcumin protects mitochondria from oxidative damage and attenuates apoptosis in cortical neurons

    Institute of Scientific and Technical Information of China (English)

    Yuan-gui ZHU; Xiao-chun CHEN; Zhi-zhe CHEN; Yu-qi ZENG; Guang-bin SHI; Yan-hua SU; Xu PENG

    2004-01-01

    AIM: To investigate the effect of curcumin on tert-butyl hydroperoxide (t-BHP)-induced oxidative damage in rat cortical neurons and to explore the possible mechanism. METHODS: Primary cultured rat cortical neurons were performed in vitro and cell viability was measured by MTT assay. DNA fragmentation was used to evaluate cell apoptosis. Intracellular reactive oxygen species (ROS) and mitochondrial membrane potential (△ψm) was determined by flow cytometric assay. Cellular glutathione (GSH) content was measured by spectrophotometer. Bcl-2family proteins, cytochrome c, cleaved caspase-3, and poly (ADP-ribose) polymerase (PARP) were detected by Western blot. RESULTS: Exposure of tBHP 100μmol/L to neurons for 60 min resulted in Aψm loss and cytochrome c release from mitochondria and subsequent activation of caspase-3 and PARP cleavation, and cell apoptosis.After removal of tBHP and then further treatment with curcumin (2.5-20μmol/L) for 18 h, curcumin abrogated △ψm loss and cytochrome c release, blocked activation of caspase 3, and altered the expression of Bcl-2 family.Further curcumin treatment also prevented cellular GSH and decreased intracellular ROS generation markedly.Curcumin eventually attenuated tBHP-induced apoptosis in cortical neurons. CONCLUSION: Curcumin may attenuate oxidative damages in cortical neurons by reducing intracellular production of ROS and protecting mitochondria from oxidative damage.

  13. Automated analysis of damages for radiation in plastics surfaces

    International Nuclear Information System (INIS)

    Analysis of damages done by the radiation in a polymer characterized by optic properties of polished surfaces, of uniformity and chemical resistance that the acrylic; resistant until the 150 centigrade grades of temperature, and with an approximate weight of half of the glass. An objective of this work is the development of a method that analyze in automated form the superficial damages induced by radiation in plastic materials means an images analyst. (Author)

  14. Molecular dynamics investigation of radiation damage in semiconductors

    Science.gov (United States)

    Good, Brian S.

    1991-01-01

    Results of a molecular dynamics investigation of the effects of radiation damage on the crystallographic structure of semiconductors are reported. Particular cosiderastion is given to the formation of point defects and small defect complexes in silicon at the end of a radiation-damage cascade. The calculations described make use of the equivalent crystal theory of Smith and Banerjea (1988). Results on the existence of an atomic displacement threshold, the defect formation energy, and some crystallographic information on the defects observed are reported.

  15. Radiation damage effects on solid state detectors

    Science.gov (United States)

    Trainor, J. H.

    1972-01-01

    Totally depleted silicon diodes are discussed which are used as nuclear particle detectors in investigations of galactic and solar cosmic radiation and trapped radiation. A study of radiation and chemical effects on the diodes was conducted. Work on electron and proton irradiation of surface barrier detectors with thicknesses up to 1 mm was completed, and work on lithium-drifted silicon devices with thicknesses of several millimeters was begun.

  16. Radiation damage to DNA: The importance of track structure

    CERN Document Server

    Hill, M A

    1999-01-01

    A wide variety of biological effects are induced by ionizing radiation, from cell death to mutations and carcinogenesis. The biological effectiveness is found to vary not only with the absorbed dose but also with the type of radiation and its energy, i.e., with the nature of radiation tracks. An overview is presented of some of the biological experiments using different qualities of radiation, which when compared with Monte Carlo track structure studies, have highlighted the importance of the localized spatial properties of stochastic energy deposition on the nanometer scale at or near DNA. The track structure leads to clustering of damage which may include DNA breaks, base damage etc., the complexity of the cluster and therefore its biological repairability varying with radiation type. The ability of individual tracks to produce clustered damage, and the subsequent biological response are important in the assessment of the risk associated with low-level human exposure. Recent experiments have also shown that...

  17. Radiation damage to accelerator components of SPring-8 storage ring

    International Nuclear Information System (INIS)

    Radiation damage to the accelerator components of the SPring-8 storage ring became serious after about four years of operation. Some rubber hoses were broken, resulting in water leakage, and some of the Synflex tubes, interlock cables, power cable covers, and so forth became damaged. Measurement of the radiation levels using GafChromic film and TLD showed that the maximum integrated radiation dose around the hoses at normal cell was 3.9x105Gy. The main radiation sources were the crotches and absorbers. Although there were two crotches and four absorbers in each of the 44 cells, two absorbers in particular caused serious radiation damage. Lead-plate shielding was installed around these absorbers to shield the nearby components

  18. Radiation damage studies on natural and synthetic rock salt

    International Nuclear Information System (INIS)

    Radiation damage studies are being made on natural rock salt from various localities, including potential repository sites and on synthetic melt-grown crystals. Sufficient information will be obtained to compute the radiation damage in repository salt at any point as a function of time, temperature, canister temperature and radiation levels, strain in the rock, salt, backfill materials, and other parameters. Most of the completed measurements have been made with unique equipment at BNL for making optical and other measurements on samples before, during, and after irradiation with 1- to 3-MeV electrons. Samples are irradiated in temperature-controlled chambers containing an inert exchange gas. Radiation damages on natural rock salts and synthetic melt-grown crystals, characterized by determining the radiation-induced F-center, colloid, and V-region absorption, are described in detail

  19. Radiation Damage to Electronics at the LHC

    CERN Document Server

    Brugger, M

    2012-01-01

    Control systems installed in LHC underground areas using COTS (Commercial Off The Shelf) components are affected by the risk of ‘Single Event Effects’. In the LHC tunnel, in addition, cumulative dose effects have also to be considered. While for the tunnel equipment certain radiation tolerant design criteria were already taken into account during the LHC construction phase, most of the equipment placed in adjacent and partly shielded areas was not conceived nor tested for their current radiation environment. Given the large amount of electronics being installed in these areas, a CERN wide project called R2E (‘Radiation To Electronics’) has been initiated to quantify the danger of radiation-induced failures and to mitigate the risk for nominal beams and beyond to below one failure a week. This paper briefly summarizes the analysis and mitigation approach chosen for the LHC, highlights a few of the encountered difficulties and the obtained experience in the following aspects: radiation fields & rela...

  20. Biophysical modelling of radiation induced damage in chromosomes

    International Nuclear Information System (INIS)

    A computational biophysical model is described which simulates radiation damage to human blood lymphocytes by photon and electron radiation. The model includes a realistic simulation of the geometrical structure of lymphocytes (plasma, nucleus, chromatin, DNA) and its chemical constituents. The simulation of damage to DNA, which is the critical target for the induction of chromosome aberrations, takes into account direct effects (energy deposition) and indirect effects (radical attack). Furthermore, an attempt has been made to correlate DNA damage within the cell nucleus to the coefficients of the dose effect relationships for the induction of dicentric chromosomes; reasonable agreement is found with relevant experimental data. (author)

  1. Investigations in silicate glasses. I. Radiation damage. II. Optical nonlinearity

    International Nuclear Information System (INIS)

    The investigation of two poorly understood but technologically important physical properties of silicate glasses and related materials is described. The use of Electron Paramagnetic Resonance to investigate the nature of radiation-induced damage in glasses exposed to a variety of high-energy radiation sources is discussed first. Second, the measurement of the nonlinear index of refraction coefficient in a variety of optical materials related to the design of high-power laser systems is described. The radiation damage investigations rely heavily on the comparison of experimental results for different experimental situations. The comparison of EPR lineshapes, absolute spin densities and power saturation behavior is used to probe a variety of microscopic and macroscopic aspects of radiation damage in glasses. Comparison of radiation damage associated with exposure to gamma rays and fast neutrons (and combinations thereof) are interpreted in terms of the microscopic damage mechanisms which are expected to be associated with the specific radiations. Comparison of radiation damage behavior in different types of glasses is also interpreted in terms of the behavior expected for the specific materials. The body of data which is generated is found to be internally self-consistent and is also generally consistent with the radiation damage behavior expected for specific situations. A new and versatile technique for measuring the nonlinear index of refraction coefficient, n2, in optical materials is described. The technique utilizes a 1 ns pulsed neodymium-glass laser system and time-resolved interferometry to determine the ratio of the coefficient n2 of sample materials to the n2 of CS2. This method avoids some of the complications associated with performing absolute measurements of n2 and allows the use of a relatively simple experimental technique. The measurements determine the nonlinear index ratios of the samples with an accuracy of about +-15 percent

  2. Attenuation coefficient of 123 keV gamma radiation by dilute solution of ferrous sulphate

    International Nuclear Information System (INIS)

    Linear and mass attenuation coefficients of 123 keV gamma radiation from Co57 by dilute solutions of FeSO4.7H2O salt are studied for varying concentrations. The mixture rule for theoretical calculation of attenuation coefficients is developed for solutions. The study explores the validity of the expected exponential attenuation absorption law for gamma radiation in solutions and also provides alternative method for direct determination of linear and mass attenuation coefficients of soluble salts in solid form without obtaining them in pure crystalline form. (author). 12 refs., 1 tab., 1 fig

  3. Early mechanisms in radiation-induced biological damage

    International Nuclear Information System (INIS)

    An introduction to the mechanisms of radiation action in biological systems is presented. Several questions about the nature of the radiation damage process are discussed, including recognition of the oxygen effects, dose-response relationships, and the importance of the hydroxyl radical

  4. Grape Seed Oil Extract Protects Against Radiation-Induced Oxidative Damage in Rats Eyes

    International Nuclear Information System (INIS)

    The present study was carried out to investigate the beneficial effects of grape seed oil on radiation-induced oxidative stress in the irradiated rat eyes. The rats were divided into three groups; control group that received distilled water, irradiated group (R) that exposed to gamma radiation as a single dose of 6.4 Gy and irradiated + grape seed oil group (R+GSO) that administered grape seed oil for seven consecutive days then exposed to the same single gamma radiation dose followed by grape seed oil for seven additional days. Histopathological results revealed protective effect of grape seed oil on the eye tissues of rat. The results lead to the conclusion that administration of GSO prior to radiation exposure may be a promising attempt in attenuating the extent of oxidative damage accompanying radiotherapy

  5. Damage caused to metals by neutron radiation

    International Nuclear Information System (INIS)

    The effect of neutrons of deuterium-tritium synthesis of metallic materials is accompanied by the formation of high-energy recoil nuclei and, consequently, cascades of atomic collisions. In this work, we calculate the size distribution of prior irradiation damage carried out by synthesis neutrons in metallic materials

  6. Electronic effects in high-energy radiation damage in tungsten

    International Nuclear Information System (INIS)

    Although the effects of the electronic excitations during high-energy radiation damage processes are not currently understood, it is shown that their role in the interaction of radiation with matter is important. We perform molecular dynamics simulations of high-energy collision cascades in bcc-tungsten using the coupled two-temperature molecular dynamics (2T-MD) model that incorporates both the effects of electronic stopping and electron–phonon interaction. We compare the combination of these effects on the induced damage with only the effect of electronic stopping, and conclude in several novel insights. In the 2T-MD model, the electron–phonon coupling results in less damage production in the molten region and in faster relaxation of the damage at short times. These two effects lead to a significantly smaller amount of the final damage at longer times. (paper)

  7. Endothelial perturbations and therapeutic strategies in normal tissue radiation damage

    International Nuclear Information System (INIS)

    Most cancer patients are treated with radiotherapy, but the treatment can also damage the surrounding normal tissue. Radiotherapy side-effects diminish patients’ quality of life, yet effective biological interventions for normal tissue damage are lacking. Protecting microvascular endothelial cells from the effects of irradiation is emerging as a targeted damage-reduction strategy. We illustrate the concept of the microvasculature as a mediator of overall normal tissue radiation toxicity through cell death, vascular inflammation (hemodynamic and molecular changes) and a change in functional capacity. Endothelial cell targeted therapies that protect against such endothelial cell perturbations and the development of acute normal tissue damage are mostly under preclinical development. Since acute radiation toxicity is a common clinical problem in cutaneous, gastrointestinal and mucosal tissues, we also focus on damage in these tissues

  8. Attenuation characteristics of materials used in radiation protection as radiation shielding

    International Nuclear Information System (INIS)

    Crystal glass has been widely used as shielding material in gamma radiation sources as well as x-ray generating equipment to replace the plumbiferous glass, in order to minimize exposure to individuals. In this work, ten plates of crystal glass, with dimensions of 20cm x 20cm and range of thicknesses from 0.5 to 2.0 cm, and barite concrete were irradiated with potential constants of 60kV, 80kV, 110kV, 150kV and gamma radiation of 60Co. The curves of attenuation and of transmission were obtained for crystal glass, barite plaster and barite concrete (mGy/mA.min) at 1 meter as a function of thickness.Crystal glass has been widely used as shielding material in gamma radiation sources as well as x-ray generating equipment to replace the plumbiferous glass, in order to minimize exposure to individuals. In this work, ten plates of crystal glass, with dimensions of 20cm x 20cm and range of thicknesses from 0.5 to 2.0 cm, and barite concrete were irradiated with potential constants of 60kV, 80kV, 110kV, 150kV and gamma radiation of 60Co. The curves of attenuation and of transmission were obtained for crystal glass, barite plaster and barite concrete (mGy/mA.min) at 1 meter as a function of thickness. (author)

  9. Radiation Damage in Reactor Materials. Part of the Proceedings of the Symposium on Radiation Damage in Solids and Reactor Materials

    International Nuclear Information System (INIS)

    Radiation damage has presented a new design parameter for the selection of materials to be used in fuel and cladding elements, moderators, structural components and pressure vessels in nuclear reactors. The severe and novel requirements for certain optimum combinations of physical and nuclear properties have emphasized the need for a better understanding of the basic mechanisms of radiation damage. This knowledge is not only essential for progress in the field of nuclear energy, but has direct applications to space technology and semi-conductor research as well. The IAEA, as part of its programme of promoting nuclear technology, therefore convened the Symposium on Radiation Damage in Solids and Reactor Materials, 7-11 May 1962. At the invitation of, and with generous material assistance from, the Government of Italy, the Symposium was held at Venice. The Symposium was primarily concerned with the investigation of the fundamental processes of radiation that underlie the behaviour of metals, alloys and ceramics that are actually useful or potentially useful reactor materials. Two sessions were devoted to studies of irradiation effects on simple metals, as these effects are easiest to interpret. Other topics included general theory, alloys, fissionable and moderator materials and special experimental techniques for radiation damage studies. The properties influenced by irradiation which were of main concern were those of primary importance to the behaviour of solids as reactor materials (e. g. dimensional stability, phase transformation, radiation hardening, fracture, fission-gas escape from uranium and its compounds). Other properties, such as optical, electrical and magnetic properties, and effects on semiconductors, ionic and other non-metallic crystals are also of interest in that these studies can increase our knowledge of the mechanism of radiation damage in solids and provide a tool for investigation into the physics of the solid state by offering a means of

  10. Space solar cells - High efficiency and radiation damage

    Science.gov (United States)

    Brandhorst, H. W., Jr.; Bernatowicz, D. T.

    1980-01-01

    The proceedings of the Third Solar Cell High Efficiency and Radiation Damage Meeting are outlined. The topics covered included high efficiency silicon solar cells, silicon solar cell radiation damage, GaAs solar cell performance, and 30 percent conversion devices. The study of radiation damage from a fundamental defect-centered basis is discussed and evaluated as a focus of future work. 18% AM0 efficiency and 0.7 V open-circuit voltages are designated as achievable goals for silicon solar cells, and the potential for 30% AM0 efficiencies from monolithic tandem cell designs without sunlight concentration is noted. In addition to its potential for 20% AM0 efficiencies, the GaAs cell offers the possibility of a radiation-insensitive power supply when operated at temperatures near 200 C.

  11. Sildenafil Attenuates Inflammation and Oxidative Stress in Pelvic Ganglia Neurons after Bilateral Cavernosal Nerve Damage

    Directory of Open Access Journals (Sweden)

    Leah A. Garcia

    2014-09-01

    Full Text Available Erectile dysfunction is a common complication for patients undergoing surgeries for prostate, bladder, and colorectal cancers, due to damage of the nerves associated with the major pelvic ganglia (MPG. Functional re-innervation of target organs depends on the capacity of the neurons to survive and switch towards a regenerative phenotype. PDE5 inhibitors (PDE5i have been successfully used in promoting the recovery of erectile function after cavernosal nerve damage (BCNR by up-regulating the expression of neurotrophic factors in MPG. However, little is known about the effects of PDE5i on markers of neuronal damage and oxidative stress after BCNR. This study aimed to investigate the changes in gene and protein expression profiles of inflammatory, anti-inflammatory cytokines and oxidative stress related-pathways in MPG neurons after BCNR and subsequent treatment with sildenafil. Our results showed that BCNR in Fisher-344 rats promoted up-regulation of cytokines (interleukin- 1 (IL-1 β, IL-6, IL-10, transforming growth factor β 1 (TGFβ1, and oxidative stress factors (Nicotinamide adenine dinucleotide phosphate (NADPH oxidase, Myeloperoxidase (MPO, inducible nitric oxide synthase (iNOS, TNF receptor superfamily member 5 (CD40 that were normalized by sildenafil treatment given in the drinking water. In summary, PDE5i can attenuate the production of damaging factors and can up-regulate the expression of beneficial factors in the MPG that may ameliorate neuropathic pain, promote neuroprotection, and favor nerve regeneration.

  12. Linear attenuation coefficient and build up factor of MCP-96 alloy for radiation shielding and protection

    Science.gov (United States)

    Hopkins, Deidre; Maqbool, Muhammad; Islam, Mohammed

    2009-10-01

    Build-up factors and linear attenuation coefficients of MCP-96 alloy are determined for radiation shielding and protection, using ^60Co and ^137Cs gamma emitters. A narrow collimated beam of γ-rays is passed through various thicknesses of MCP-96 alloy and the attenuation in the intensity of the beam is determined. The thickness of the 4 x 4 cm^2 blocks varies from 0.5 cm to 6 cm. Plotting the thickness of the alloy and the corresponding intensity of the beam allowed us to determine its linear attenuation coefficient. The narrow beam geometry is then replaced by broad beam geometry by removing the collimator and the radiation beam is able to interact with the MCP-96 alloy at all possible positions facing the radiation source. Additional radiations obtained by the detector as a result from the scattering of radiation develops the build-up factor. The buildup factor is then calculated using the attenuated beam received by the detector in the broad beam geometry and in the narrow beam geometry. The buildup factor is found to be dependent on the thickness of the MCP-96 attenuator, the beam energy and the source to attenuator distance. These values are providing ways for dose correction in radiation oncology and radiation shielding and protection when MCP-96 is used as tissue compensator or for radiation protection purposes.

  13. Ambient ultraviolet radiation induces protective responses in soybean but does not attenuate indirect defense

    International Nuclear Information System (INIS)

    We investigated the effects of ambient ultraviolet (UV) radiation on (i) the performance and chemistry of soybean plants, (ii) the performance of Spodoptera frugiperda and (iii) the foraging behavior of the herbivore's natural enemy Cotesia marginiventris which exploits herbivore-induced plant volatiles (VOC) for host location. The accumulation of protective phenolics was faster in plants receiving ambient UV than in controls exposed to sun light lacking UV. Accordingly, isorhamnetin- and quercetin-based flavonoids were increased in UV exposed plants. No UV effects were found on the performance and feeding behavior of S. frugiperda. Herbivore-damaged plants emitted the same VOC when grown under ambient or attenuated UV for 5, 10 or 30 days. Consequently, C. marginiventris was attracted but did not discriminate between exposed and unexposed soybeans. In summary, ambient UV radiation affected soybean morphology and physiology but did not destabilize interactions between trophic levels. - Ambient ultraviolet radiation does not alter induced VOC emission in soybean and thus host location of the parasitoid Cotesia marginiventris remains effective

  14. Human T-cell leukemia virus type 1 tax attenuates the ATM-mediated cellular DNA damage response.

    Science.gov (United States)

    Chandhasin, Chandtip; Ducu, Razvan I; Berkovich, Elijahu; Kastan, Michael B; Marriott, Susan J

    2008-07-01

    Genomic instability, a hallmark of leukemic cells, is associated with malfunctioning cellular responses to DNA damage caused by defective cell cycle checkpoints and/or DNA repair. Adult T-cell leukemia, which can result from infection with human T-cell leukemia virus type 1 (HTLV-1), is associated with extensive genomic instability that has been attributed to the viral oncoprotein Tax. How Tax influences cellular responses to DNA damage to mediate genomic instability, however, remains unclear. Therefore, we investigated the effect of Tax on cellular pathways involved in recognition and repair of DNA double-strand breaks. Premature attenuation of ATM kinase activity and reduced association of MDC1 with repair foci were observed in Tax-expressing cells. Following ionizing radiation-induced S-phase checkpoint activation, Tax-expressing cells progressed more rapidly than non-Tax-expressing cells toward DNA replication. These results demonstrate that Tax expression may allow premature DNA replication in the presence of genomic lesions. Attempts to replicate in the presence of these lesions would result in gradual accumulation of mutations, leading to genome instability and cellular transformation. PMID:18434398

  15. Radiation damage at the molecular level: Nanodosimetry

    International Nuclear Information System (INIS)

    One of the main practical use of the model is its use as a tool of nanodosimetry which basically consists in characterizing the effect of radiation on nano volumes (comparable to the DNA of volumes) in terms of link breaks and molecular dissociations. (Author)

  16. Radiation-damaged tyrosinase molecules are inactive

    International Nuclear Information System (INIS)

    Target analysis of radiation inactivation of mushroom tyrosinase yields different target sizes for diphenoloxidase and monophenoloxidase activities, which correspond to the subunits H and HL2 (or HL), respectively. After gel electrophoresis of irradiated samples, all diphenoloxidase activity is observed at the same position as seen in the original material. Radiolytic fragments contain no detectable activity, consistent with a fundamental assumption of target theory

  17. The influence of gamma-radiation on the attenuation of two graded-index optical fibres

    International Nuclear Information System (INIS)

    The attenuation induced by gamma-radiation in two graded-index optical fibres has been measured at wavelengths of 0.85, 1.30 and 1.55 μm. Both the attenuation at a dose of 3 krad and the relaxation after the irradiation have been measured. In addition the attenuation during irradiation to a maximum dose of 100 krad has been measured. (author). 12 refs.; 18 figs.; 8 tabs

  18. Determination of mass attenuation coefficients of gamma radiation for different fuel compositions

    International Nuclear Information System (INIS)

    In the work experimental methods for determination of gamma-radiation mass attenuation coefficients by the way of attenuation curves reading is given. The gamma-spectrometric method is used for 235U content in different fuel compositions (uranium dioxide (UO2), uranium intermetallic (U(AlSi)3), uranium mononitride (UN), double uranium carbide (UC+ZrC+C). Attenuation curves for gamma-quanta with Eγ=185 keV is given

  19. Spectrum of complex DNA damages depends on the incident radiation

    Science.gov (United States)

    Hada, M.; Sutherland, B.

    Ionizing radiation induces clustered DNA damages in DNA-two or more abasic sites oxidized bases and strand breaks on opposite DNA strands within a few helical turns Clustered damages are considered to be difficult to repair and therefore potentially lethal and mutagenic damages Although induction of single strand breaks and isolated lesions has been studied extensively little is known of factors affecting induction of clusters other than double strand breaks DSB The aim of the present study was to determine whether the type of incident radiation could affect yield or spectra of specific clusters Genomic T7 DNA a simple 40 kbp linear blunt-ended molecule was irradiated in non-scavenging buffer conditions with Fe 970 MeV n Ti 980 MeV n C 293 MeV n Si 586 MeV n ions or protons 1 GeV n at the NASA Space Radiation Laboratory or with 100 kVp X-rays Irradiated DNA was treated with homogeneous Fpg or Nfo proteins or without enzyme treatment for DSB quantitation then electrophoresed in neutral agarose gels DSB Fpg-OxyPurine clusters and Nfo-Abasic clusters were quantified by number average length analysis The results show that the yields of all these complex damages depend on the incident radiation Although LETs are similar protons induced twice as many DSBs than did X-rays Further the spectrum of damage also depends on the radiation The yield damage Mbp Gy of all damages decreased with increasing linear energy transfer LET of the radiation The relative frequencies of DSBs to Abasic- and OxyBase clusters were higher

  20. A beginner’s guide to radiation damage

    Energy Technology Data Exchange (ETDEWEB)

    Holton, James M., E-mail: jmholton@lbl.gov [Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158-2330 (United States); Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2009-03-01

    Radiation damage considerations affecting data collection by more than a factor of two are summarized and damage avoidance strategies are suggested. Many advances in the understanding of radiation damage to protein crystals, particularly at cryogenic temperatures, have been made in recent years, but with this comes an expanding literature, and, to the new breed of protein crystallographer who is not really interested in X-ray physics or radiation chemistry but just wants to solve a biologically relevant structure, the technical nature and breadth of this literature can be daunting. The purpose of this paper is to serve as a rough guide to radiation damage issues, and to provide references to the more exacting and detailed work. No attempt has been made to report precise numbers (a factor of two is considered satisfactory), and, since there are aspects of radiation damage that are demonstrably unpredictable, the ‘worst case scenario’ as well as the ‘average crystal’ are discussed in terms of the practicalities of data collection.

  1. On radiation damage to normal tissues and its treatment. Pt. 2; Anti-inflammatory drugs

    Energy Technology Data Exchange (ETDEWEB)

    Michalowski, A.S. (MRC Cyclotron Unit, Hammersmith Hospital, London (United Kingdom))

    1994-01-01

    In addition to transiently inhibiting cell cycle progression and sterilizing those cells capable of proliferation, irradiation disturbs the homeostasis effected by endogenous mediators of intercellular communication (humoral component of tissue response to radiation). Changes in the mediator levels may modulate radiation effects either by a assisting a return to normality (e.g., through a rise in H-type cell lineage-specific growth factors) or by aggravating the damage. The latter mode is illustrated with reports on changes in eicosanoid levels after irradiation and on results of empirical treatment of radiation injuries with anti-inflammatory drugs. Prodromal, acute and chronic effects of radiation are accompanied by excessive production of eicosanoids (prostaglandins, prostacyclin, thromboxanes and leukotrienes). These endogenous mediators of inflammatory reactions may be responsible for the vasodilatation, vasoconstriction, increased microvascular permeability, thrombosis and chemotaxis observed after radiation exposure. Glucocorticoids inhibit eicosanoid synthesis primarily by interfering with phospholipase A[sub 2] whilst non-steroidal anti-inflammatory drugs prevent prostaglandin/thromboxane synthesis by inhibiting cycloxygenase. When administered after irradiation on empirical grounds, drugs belonging to both groups tend to attenuate a range of prodomal, acute and chronic effects of radiation in man and animals. Taken together, these two sets of observations are highly suggestive of a contribution of humoral factors to the adverse responses of normal tissues and organs to radiation. A full account of radiation damage should therefore consist of complementary descriptions of cellular and humoral events. Further studies on anti-inflammatory drug treatment of radiation damage to normal organs are justified and desirable. (orig.).

  2. Extra lethal damage due to residual incompletely repaired sublethal damage in hyperfractionated and continuous radiation treatment

    International Nuclear Information System (INIS)

    In the conventional linear--quadratic model of single-dose response, the α and β terms reflect lethal damage created during the delivery of a dose, from two different presumed molecular processes, one linear with dose, the other quadratic. With the conventional one-fraction-per-day (or less) regimens, the sublethal damage (SLD), presumably repairing exponentially over time, is essentially completely fixed by the time of the next dose of radiation. If this assumption is true, the effects of subsequent fractions of radiation should be independent, that is, there should be little, if any, reversible damage left from previous fractions, at the time of the next dose. For multiple daily fractions, or for the limiting case, continuous radiation, this simplification may overlook damaged cells that have had insufficient time for repair. A generalized method is presented for accounting for extra lethal damage (ELD) arising from such residual SLD for hyperfractionation and continuous irradiation schemes. It may help to predict differences in toxicity and tumor control, if any, obtained with ''unconventional'' treatment regimens. A key element in the present model is the finite size and the dynamic character of the pool of sublethal damage. Besides creating the usual linear and quadratic components of lethal damage, each new fraction converts a certain fraction of the existing SLD into ELD, and creates some new SLD

  3. Extra lethal damage due to residual incompletely repaired sublethal damage in hyperfractionated and continuous radiation treatment

    Energy Technology Data Exchange (ETDEWEB)

    Chen, J.; van de Geijn, J.; Goffman, T. (ROB, DCT, NCI, NIH, Bethesda, Maryland 20892 (US))

    1991-05-01

    In the conventional linear--quadratic model of single-dose response, the {alpha} and {beta} terms reflect lethal damage created {ital during} the delivery of a dose, from two different presumed molecular processes, one linear with dose, the other quadratic. With the conventional one-fraction-per-day (or less) regimens, the sublethal damage (SLD), presumably repairing exponentially over time, is essentially completely fixed by the time of the next dose of radiation. If this assumption is true, the effects of subsequent fractions of radiation should be independent, that is, there should be little, if any, reversible damage left from previous fractions, at the time of the next dose. For multiple daily fractions, or for the limiting case, continuous radiation, this simplification may overlook damaged cells that have had insufficient time for repair. A generalized method is presented for accounting for extra lethal damage (ELD) arising from such residual SLD for hyperfractionation and continuous irradiation schemes. It may help to predict differences in toxicity and tumor control, if any, obtained with unconventional'' treatment regimens. A key element in the present model is the finite size and the dynamic character of the pool of sublethal damage. Besides creating the usual linear and quadratic components of lethal damage, each new fraction converts a certain fraction of the existing SLD into ELD, and creates some new SLD.

  4. Indomethacin attenuation of radiation-induced hyperthermia does not modify radiation-induced motor hypoactivity

    Energy Technology Data Exchange (ETDEWEB)

    Ferguson, J.L.; Kandasamy, S.B.; Harris, A.H.; Davis, H.D.; Landauer, M.R. [Armed Forces Radiobiology Research Inst., Bethesda, MD (United States)

    1996-09-01

    Exposure of rats to 5-10 Gy of ionizing radiation produces hyperthermia and reduces motor activity. Previous studies suggested that radiation-induced hyperthermia results from a relatively direct action on the brain and is mediated by prostaglandins. To test the hypothesis that hypoactivity may be, in part, a thermoregulatory response to this elevation in body temperature, adult male rats were given indomethacin (0.0, 0.5, 1.0, and 3.0 mg/kg, intraperitoneally), a blocker of prostaglandin synthesis, and were either irradiated (LINAC 18.6 MeV (nominal) high-energy electrons, 10 Gy at 10 Gy/min, 2.8 {mu}sec pulses at 2 Hz) or sham-irradiated. The locomotor activity of all rats was then measured for 30 min in a photocell monitor for distance traveled and number of vertical movements. Rectal temperatures of irradiated rats administered vehicle only were elevated by 0.9{+-}0.2degC at the beginning and the end of the activity session. Although indomethacin, at the two higher doses tested, attenuated the hyperthermia in irradiated rats by 52-75%, it did not attenuate radiation-induced reductions in motor activity. These results indicate that motor hypoactivity after exposure to 10 Gy of high-energy electrons is not due to elevated body temperature or to the increased synthesis of prostaglandins. (author)

  5. Radioprotective role of imidazole on radiation-induced chromosomal damage in rat bone marrow cells

    International Nuclear Information System (INIS)

    Whole body gamma irradiation (4 Gy) of male laboratory rats, Rattus norvegicus, induced chromosomal damage and decrease of mitotic index in bone marrow cells which were investigated 0-1/2, 6, 24 and 48 hr. After treatment. Chromosomal aberrations observed consisted of chromatid breaks, centromeric attenuation, chromosomal translocations and rings. The intraperitoneal administration of imidazole at 0.35 mg/g body weight prior to irradiation exerted a definite protective character against radiation induced chromosomal aberration and affected the mitotic index of bone marrow cells

  6. Radiation damage of light water reactor materials

    International Nuclear Information System (INIS)

    Reactor materials and irradiation conditions have changed as reactor types advanced from light water reactors to fast breeder reactors and future nuclear fusion reactors, but the physical and chemical processes of irradiation damage at the final stage of service of the structural materials of light water reactors must be studied more in detail. The research on the secular change of LWR materials under irradiation is regarded as most important. Especially in the problems of the embrittlement of pressure vessels, the irradiation damage of in-core structures, and the irradiation growth and creep of zircaloy, it has become more important to continuously evaluate the secular deterioration and assure the soundness, and to elucidate the process of microstructure chanage of the materials under irradiation for forecasting the life. The structure and the materials of light water reactors are explained. The neutron irradiation embrittlement of reactor pressure vessels must be forecast more accurately as the years of operation elapse. The factors affecting the irradiation embrittlement are described. The physical model and the microstructure of the irradiation embittlement are shown. As for in-core structures, intergranular stress corrosion cracking is discussed. As for zirconium alloy, the factors affecting the irradiation creep and growth are explained. (K.I.)

  7. Request from radiation damage evaluation in materials

    International Nuclear Information System (INIS)

    Radiation transport calculations in a PWR using cross-section data sets based on JENDL3.2 showed that the calculated neutron fluence agreed well with the dosimeter measurements and that the fast neutron flux and dpa rate differed within 10% from to those calculated using ENDF/B-IV and ENDF/B-VI based data sets. Calculations of helium generation in structural materials in the PWR using ENDF/B-VI showed that the dominant source of helium is the (n, α) reaction of 59Ni and that the calculated helium content agreed with the measurements. For accurate estimation of radiation field from a material viewpoint, it is desirable to construct proper cross-section libraries, which have a proper energy group structure and contain sufficient elements including 59Ni as an indispensable element. (author)

  8. Opportunities for nutritional amelioration of radiation-induced cellular damage

    Science.gov (United States)

    Turner, Nancy D.; Braby, Leslie A.; Ford, John; Lupton, Joanne R.

    2002-01-01

    The closed environment and limited evasive capabilities inherent in space flight cause astronauts to be exposed to many potential harmful agents (chemical contaminants in the environment and cosmic radiation exposure). Current power systems used to achieve space flight are prohibitively expensive for supporting the weight requirements to fully shield astronauts from cosmic radiation. Therefore, radiation poses a major, currently unresolvable risk for astronauts, especially for long-duration space flights. The major detrimental radiation effects that are of primary concern for long-duration space flights are damage to the lens of the eye, damage to the immune system, damage to the central nervous system, and cancer. In addition to the direct damage to biological molecules in cells, radiation exposure induces oxidative damage. Many natural antioxidants, whether consumed before or after radiation exposure, are able to confer some level of radioprotection. In addition to achieving beneficial effects from long-known antioxidants such as vitamins E and C and folic acid, some protection is conferred by several recently discovered antioxidant molecules, such as flavonoids, epigallocatechin, and other polyphenols. Somewhat counterintuitive is the protection provided by diets containing elevated levels of omega-3 polyunsaturated fatty acids, considering they are thought to be prone to peroxidation. Even with the information we have at our disposal, it will be difficult to predict the types of dietary modifications that can best reduce the risk of radiation exposure to astronauts, those living on Earth, or those enduring diagnostic or therapeutic radiation exposure. Much more work must be done in humans, whether on Earth or, preferably, in space, before we are able to make concrete recommendations.

  9. Application of radiation damage effects in dosimetry

    International Nuclear Information System (INIS)

    some general aspects of radiation dosimetry are outlined. The techniques of radiophotoluminescence, radiothermoluminescence and exo-electron emission are discussed individually. It is thought that the trend in personnel dosimetry is such that thermoluminescence will steadily replace film and photoluminescence techniques over the next decade, and that more unusual techniques, such as exo-electron emission, will make inroads only for special purposes. (B.R.H.)

  10. Solar Radiation Damage to Human Skin Mitochondria

    OpenAIRE

    Zanchetta, Luciene, (Thesis)

    2010-01-01

    The central objective of this study was to assess solar radiation-induced changes in cellular function, mitochondrial function and mitochondrial DNA to further investigate the role of these energy-dedicated and metabolically essential organelles in the response to the main environmental stressor associated with skin cancer initiation. An in vitro approach was chosen employing the human malignant melanoma (A375) and human amelanotic melanoma (C32) cells and the human spontaneously immortalized...

  11. Ocular damage induced by near-ultraviolet laser radiation

    International Nuclear Information System (INIS)

    A quantitative study was conducted of ocular damage thresholds in the rhesus monkey eye from krypton, argon, and nitrogen laser radiation. Corneal and lenticular thresholds are reported for various laser beam parameters. Corneal damage was found to occur following incident energy doses of approximately 60 to 70 Joules per square centimeter (J./cm.2) for pulsewidths ranging from 250 μsec to 120 sec. The results are consistent with a photochemical damage mechanism. With certain exposure parameters, cataracts were induced with lower energy doses than required to cause corneal damage. The lenticular thresholds, however, appear to be consistent with a thermal rather than a photochemical mechanism. Corneal and lenticular hazards of near-ultraviolet (near-uv) lasers are discussed in terms of existing safety standards for laser radiation

  12. Optimization of data collection taking radiation damage into account

    International Nuclear Information System (INIS)

    Software implementing a new method for the optimal choice of data-collection parameters, accounting for the effects of radiation damage, is presented. To take into account the effects of radiation damage, new algorithms for the optimization of data-collection strategies have been implemented in the software package BEST. The intensity variation related to radiation damage is approximated by log-linear functions of resolution and cumulative X-ray dose. Based on an accurate prediction of the basic characteristics of data yet to be collected, BEST establishes objective relationships between the accessible data completeness, resolution and signal-to-noise statistics that can be achieved in an experiment and designs an optimal plan for data collection

  13. High-energy radiation damage in zirconia: Modeling results

    Science.gov (United States)

    Zarkadoula, E.; Devanathan, R.; Weber, W. J.; Seaton, M. A.; Todorov, I. T.; Nordlund, K.; Dove, M. T.; Trachenko, K.

    2014-02-01

    Zirconia is viewed as a material of exceptional resistance to amorphization by radiation damage, and consequently proposed as a candidate to immobilize nuclear waste and serve as an inert nuclear fuel matrix. Here, we perform molecular dynamics simulations of radiation damage in zirconia in the range of 0.1-0.5 MeV energies with account of electronic energy losses. We find that the lack of amorphizability co-exists with a large number of point defects and their clusters. These, importantly, are largely isolated from each other and therefore represent a dilute damage that does not result in the loss of long-range structural coherence and amorphization. We document the nature of these defects in detail, including their sizes, distribution, and morphology, and discuss practical implications of using zirconia in intense radiation environments.

  14. Excitation of surface-radiation exciton-polariton modes at strong attenuations of excitons

    International Nuclear Information System (INIS)

    Formation of a photoluminescence spectrum of surface-radiation exciton-polariton modes is analysed at strong exciton attenuations when criteria of applicability of Boltzmann kinetic equation are broken for function of polariton distribution. (author)

  15. Parathyroid hormone attenuates radiation-induced increases in collagen crosslink ratio at periosteal surfaces of mouse tibia.

    Science.gov (United States)

    Oest, Megan E; Gong, Bo; Esmonde-White, Karen; Mann, Kenneth A; Zimmerman, Nicholas D; Damron, Timothy A; Morris, Michael D

    2016-05-01

    As part of our ongoing efforts to understand underlying mechanisms contributing to radiation-associated bone fragility and to identify possible treatments, we evaluated the longitudinal effects of parathyroid hormone (PTH) treatment on bone quality in a murine model of limited field irradiation. We hypothesized PTH would mitigate radiation-induced changes in the chemical composition and structure of bone, as measured by microscope-based Raman spectroscopy. We further hypothesized that collagen crosslinking would be especially responsive to PTH treatment. Raman spectroscopy was performed on retrieved tibiae (6-7/group/time point) to quantify metrics associated with bone quality, including: mineral-to-matrix ratio, carbonate-to-phosphate ratio, mineral crystallinity, collagen crosslink (trivalent:divalent) ratio, and the mineral and matrix depolarization ratios. Irradiation disrupted the molecular structure and orientation of bone collagen, as evidenced by a higher collagen crosslink ratio and lower matrix depolarization ratio (vs. non-irradiated control bones), persisting until 12weeks post-irradiation. Radiation transiently affected the mineral phase, as evidenced by increased mineral crystallinity and mineral-to-matrix ratio at 4weeks compared to controls. Radiation decreased bone mineral depolarization ratios through 12weeks, indicating increased mineral alignment. PTH treatment partially attenuated radiation-induced increases in collagen crosslink ratio, but did not restore collagen or mineral alignment. These post-radiation matrix changes are consistent with our previous studies of radiation damage to bone, and suggest that the initial radiation damage to bone matrix has extensive effects on the quality of tissue deposited thereafter. In addition to maintaining bone quality, preventing initial radiation damage to the bone matrix (i.e. crosslink ratio, matrix orientation) may be critical to preventing late-onset fragility fractures. PMID:26960578

  16. Studying Radiation Damage in Structural Materials by Using Ion Accelerators

    Science.gov (United States)

    Hosemann, Peter

    2011-02-01

    Radiation damage in structural materials is of major concern and a limiting factor for a wide range of engineering and scientific applications, including nuclear power production, medical applications, or components for scientific radiation sources. The usefulness of these applications is largely limited by the damage a material can sustain in the extreme environments of radiation, temperature, stress, and fatigue, over long periods of time. Although a wide range of materials has been extensively studied in nuclear reactors and neutron spallation sources since the beginning of the nuclear age, ion beam irradiations using particle accelerators are a more cost-effective alternative to study radiation damage in materials in a rather short period of time, allowing researchers to gain fundamental insights into the damage processes and to estimate the property changes due to irradiation. However, the comparison of results gained from ion beam irradiation, large-scale neutron irradiation, and a variety of experimental setups is not straightforward, and several effects have to be taken into account. It is the intention of this article to introduce the reader to the basic phenomena taking place and to point out the differences between classic reactor irradiations and ion irradiations. It will also provide an assessment of how accelerator-based ion beam irradiation is used today to gain insight into the damage in structural materials for large-scale engineering applications.

  17. Attenuation of gamma-radiation by multilayer polymer disperse-filled structures

    International Nuclear Information System (INIS)

    The results of attenuation of gamma-radiation in multilayered structures containing polymer matrix and super-dispersed powders are presented. These structures, which represented as combination of layers with gradient of effective atomic number, reveal anisotropy of attenuation of low-energy gamma-radiation in normal direction relative to plane of layers. Application of structures in engineering materials of containers for radioactive waste or spent fuel provide reduction of their weight comparatively of containers made from steel and concrete.

  18. Raman study of radiation-damaged zircon under hydrostatic compression

    Science.gov (United States)

    Nasdala, Lutz; Miletich, Ronald; Ruschel, Katja; Váczi, Tamás

    2008-12-01

    Pressure-induced changes of Raman band parameters of four natural, gem-quality zircon samples with different degrees of self-irradiation damage, and synthetic ZrSiO4 without radiation damage, have been studied under hydrostatic compression in a diamond anvil cell up to ~10 GPa. Radiation-damaged zircon shows similar up-shifts of internal SiO4 stretching modes at elevated pressures as non-damaged ZrSiO4. Only minor changes of band-widths were observed in all cases. This makes it possible to estimate the degree of radiation damage from the width of the ν3(SiO4) band of zircon inclusions in situ, almost independent from potential “fossilized pressures” or compressive strain acting on the inclusions. An application is the non-destructive analysis of gemstones such as corundum or spinel: broadened Raman bands are a reliable indicator of self-irradiation damage in zircon inclusions, whose presence allows one to exclude artificial color enhancement by high-temperature treatment of the specimen.

  19. Nuclear data for radiation damage estimates for reactor structural materials

    International Nuclear Information System (INIS)

    The IAEA Consultants' Meeting on Nuclear Data for Radiation Damage Estimates for Reactor Structural Materials was convened by the IAEA Nuclear Data Section in Santa Fe, New Mexico, USA from 20-22 May 1985. The meeting was attended by 17 participants from 10 countries and 2 international organizations. The main objectives of the meeting were to review the status of displacement cross sections and the requirements for nuclear data needed for radiation damage estimates in reactor structural materials, and to develop recommendations for future activities in this field. This publication contains the text of all the papers prepared especially for this meeting including the conclusions and recommendations worked out during the meeting

  20. Radiation damage of pixelated photon detector by neutron irradiation

    Science.gov (United States)

    Nakamura, Isamu

    2009-10-01

    Radiation Damage of Pixelated Photon Detector by neutron irradiation is reported. MPPC, one of PPD or Geiger-mode APD, developed by Hamamatsu Photonics, is planned to be used in many high energy physics experiments. In such experiments radiation damage is a serious issue. A series of neutron irradiation tests is performed at the Reactor YAYOI of the University of Tokyo. MPPCs were irradiated at the reactor up to 1012 neutron/cm2. In this paper, the effect of neutron irradiation on the basic characteristics of PPD including gain, noise rate, photon detection efficiency is presented.

  1. Radiation Damage of Beryllium Reflector for Research Reactor Application

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Suk Hoon [Korea Atomic Energy Research Institute Daejeon (Korea, Republic of)

    2013-07-01

    Beryllium is considered as a reflector material for the research reactor. The neutron fluence results in significant damage of material structure and corresponding degradation of physical.mechanical properties. In this study, the proton radiation damage of the beryllium grade manufactured by hot extrusion was investigated to emulate the effect of neutron radiation. The samples were irradiated by protons at room temperature; the acceleration voltage, and the proton amounts were 120keV, and 2.0 Χ 10{sup 18} ions/cm{sup 2}, respectively. The neutron irradiation experiment also have been conducted in HANARO, their results will be discussed in terms of swelling, and microstructure evolution.

  2. Role of endothelium in radiation-induced normal tissue damages

    International Nuclear Information System (INIS)

    More than half of cancers are treated with radiation therapy alone or in combination with surgery and/or chemotherapy. The goal of radiation therapy is to deliver enough ionising radiation to destroy cancer cells without exceeding the level that the surrounding healthy cells can tolerate. Unfortunately, radiation-induced normal tissue injury is still a dose limiting factor in the treatment of cancer with radiotherapy. The knowledge of normal tissue radiobiology is needed to determine molecular mechanisms involved in normal tissue pathogenic pathways in order to identify therapeutic targets and develop strategies to prevent and /or reduce side effects of radiation therapy. The endothelium is known to play a critical role in radiation-induced injury. Our work shows that endothelial cells promote vascular smooth muscle cell proliferation, migration and fibro-genic phenotype after irradiation. Moreover, we demonstrate for the first time the importance of PAI-1 in radiation-induced normal tissue damage suggesting that PAI-1 may represent a molecular target to limit injury following radiotherapy. We describe a new role for the TGF-b/Smad pathway in the pathogenesis of radiation-induced damages. TGF-b/Smad pathway is involved in the fibro-genic phenotype of VSMC induced by irradiated EC as well as in the radiation-induced PAI-1 expression in endothelial cells. (author)

  3. Inducible HSP70 Protects Radiation-Induced Salivary Gland Damage

    International Nuclear Information System (INIS)

    Irradiation (IR) delivered to the head and neck is a common treatment for malignancies. Salivary glands in the irradiation field are severely damaged, and consequently this resulted in marked salivary hypofunction. While the exact mechanism of salivary gland damage remains enigmatic, fluid secreting acinar cells are lost, and saliva output is dramatically reduced. Previously we have reported that inducible heat shock protein 70 (HSP70i) induced radioresistance in vitro. Moreover, HSP70i localized to salivary glands by gene transfer has great potential for the treatment of salivary gland. Herein, we investigated whether HSP70 can use as radio protective molecules for radiation-induced salivary gland damage in vivo

  4. The initial physical damage produced by ionizing radiations

    International Nuclear Information System (INIS)

    Biophysical analyses of radiation tracks emphasize the importance of very local clustering of atomic damage within a track over microscopic distances as small as a few nanometres. They show that there must be a wide spectrum of initial physical damage within or very near to relevant macromolecules, such as DNA, and that the chemical, biochemical, repair and cellular consequences should differ considerably across this spectrum. An attempt has been made to divide this spectrum into four broad classes in order to guide development and application of assays which may better reveal the complexities and relevance of damage to DNA, and associated structures, within these classes. (author)

  5. The role of gases in radiation damage patterns

    International Nuclear Information System (INIS)

    The paper reviews the radiation damage phenomena in metals after light element irradiation, in particular helium. The irradiation-induced defects, the microstructural damages associated, and the changes in mechanical properties induced are discussed in terms of the homologous temperature and the CTR-parameter combining the amount of atoms injected and the amount of damage created. Particular attention is paid to the atomistic approach to describing small-size effects. Large-size effects, currently created in a phenomonological manner, are discussed in the last section and the phenomena of gas re-emission, gas bubbles are considered in some detail. (orig.)

  6. Alleviation of acute radiation damages by post-irradiation treatments

    International Nuclear Information System (INIS)

    Radiation induced hematopoietic and gastro-intestinal damages in mice were tried to alleviate experimentally by post-treatment. Combined treatment of OK-432 and aztreonam clearly prevented the radiation induced sepsis and elevated the survival rate in mice; the survival was 80% in the OK-432 plus aztreonam group while it was 55% in the group treated with OK-432 alone and 0% with saline. Irsogladine maleate, an anti-ulcer drug, increased the survival rate of jejunal crypt stem cells with a clear dose-related trend. The D0 for irsogladine maleate was 2.8 Gy although it was 2.3 Gy for saline, These findings suggest that some conventional drugs are effective for radiation induced hematopoietic and gastro-intestinal damages and the possibility that they can be applied for people exposed to radiation accidentally. (author)

  7. Repair of gamma radiation-induced damage : Micrococcus radiophilus

    International Nuclear Information System (INIS)

    The gamma radiation survival curve of M. radiophilus exhibits an extensive shoulder followed by exponential kill, indicating the efficiency of this bacterium for repairing gamma radiation induced damage. It differs morphologically, biochemically and genetically from M. radiodurans. Examination of DNA strand breaks using sucrose density gradient revealed the cell's ability to repair double and single strand breaks. Studies with alkaline gradients suggest that the fast repair of single strand scissions in M. radiophilus cellular DNA may be instantaneous. (author)

  8. Ligularia fischeri extract attenuates liver damage induced by chronic alcohol intake.

    Science.gov (United States)

    Kim, Dongyeop; Kim, Gyeong-Woo; Lee, Seon-Ho; Han, Gi Dong

    2016-08-01

    Context Ligularia fischeri (Ledebour) Turcz. (Compositae) has been used as a leafy vegetable and in traditional medicine to treat hepatic disorder in East Asia. Objective The present study explores the antioxidant activity of LF aqueous extract on EtOH-induced oxidative stress accompanied by hepatotoxicity both in vitro and in vivo. Materials and methods In vitro study using the mouse liver NCTC-1469 cell line was conducted to estimate the cytotoxicity as well as the inhibitory effect of LF extract against alcohol-treated cell damage. In vivo study used an alcohol-fed Wister rat model orally administered EtOH (3.95 g/kg of body weight/d) with or without LF extract (100 or 200 mg/kg body weight) for 6 weeks. Serum and liver tissue were collected to evaluate hepatic injury and antioxidant-related enzyme activity. Results The EC50 value for the DPPH radical scavenging capacity of LF extract was 451.5 μg/mL, whereas the IC50 value of LF extract in terms of EtOH-induced reactive oxygen species (ROS) generation was 98.3 μg/mL without cell cytotoxicity. LF extract (200 mg/kg body weight) significantly reduced the triglyceride content of serum (33%) as well as hepatic lipid peroxidation (36%), whereas SOD activity was elevated three-fold. LF extract suppressed expression of CYP2E1 and TNF-α, and attenuated alcohol-induced abnormal morphological changes. Discussion and conclusion LF extract attenuated liver damage induced by alcoholic oxidative stress through inhibition of ROS generation, down-regulation of CYP2E1, and activation of hepatic antioxidative enzymes. Homeostasis of the antioxidative defence system in the liver by LF extract mitigated hepatic disorder following chronic alcohol intake. PMID:26799831

  9. Radiation-induced normal tissue damage: implications for radiotherapy

    International Nuclear Information System (INIS)

    Radiotherapy is an important treatment modality for many malignancies, either alone or as a part of combined modality treatment. However, despite technological advances in physical treatment delivery, patients suffer adverse effects from radiation therapy due to normal tissue damage. These side effects may be acute, occurring during or within weeks after therapy, or intermediate to late, occurring months to years after therapy. Minimizing normal tissue damage from radiotherapy will allow enhancement of tumor killing and improve tumor control and patients quality of life. Understanding mechanisms through which radiation toxicity develops in normal tissue will facilitate the development of next generation radiation effect modulators. Translation of these agents to the clinic will also require an understanding of the impact of these protectors and mitigators on tumor radiation response. In addition, normal tissues vary in radiobiologically important ways, including organ sensitivity to radiation, cellular turnover rate, and differences in mechanisms of injury manifestation and damage response. Therefore, successful development of radiation modulators may require multiple approaches to address organ/site-specific needs. These may include treatments that modify cellular damage and death processes, inflammation, alteration of normal flora, wound healing, tissue regeneration and others, specifically to counter cancer site-specific adverse effects. Further, an understanding of mechanisms of normal tissue damage will allow development of predictive biomarkers; however harmonization of such assays is critical. This is a necessary step towards patient-specific treatment customization. Examples of important adverse effects of radiotherapy either alone or in conjunction with chemotherapy, and important limitations in the current approaches of using radioprotectors for improving therapeutic outcome will be highlighted. (author)

  10. Radiation Damage Studies of Silicon Photomultipliers

    CERN Document Server

    Bohn, P; Hazen, E; Heering, A; Rohlf, J; Freeman, J; Los, S; Cascio, E; Kuleshov, S; Musienko, Y; Piemonte, C

    2008-01-01

    We report on the measurement of the radiation hardness of silicon photomultipliers (SiPMs) manufactured by Fondazione Bruno Kessler in Italy (1 mm$^2$ and 6.2 mm$^2$), Center of Perspective Technology and Apparatus in Russia (1 mm$^2$ and 4.4 mm$^2$), and Hamamatsu Corporation in Japan (1 mm$^2$). The SiPMs were irradiated using a beam of 212 MeV protons at Massachusetts General Hospital, receiving fluences of up to $3 \\times 10^{10}$ protons per cm$^2$ with the SiPMs at operating voltage. Leakage currents were read continuously during the irradiation. The delivery of the protons was paused periodically to record scope traces in response to calibrated light pulses to monitor the gains, photon detection efficiencies, and dark counts of the SiPMs. The leakage current and dark noise are found to increase with fluence. Te leakage current is found to be proportional to the mean square deviation of the noise distribution, indicating the dark counts are due to increased random individual pixel activation, while SiPM...

  11. Radiation damage in reactor cavity concrete

    International Nuclear Information System (INIS)

    License renewal up to 60 years and the possibility of subsequent license renewal to 80 years has established a renewed focus on long-term aging of nuclear generating stations materials, and recently, on concrete (large irreplaceable sections of most nuclear generating stations include concrete). The Electric Power Research Institute (EPRI) and Oak Ridge National Laboratory (ORNL) have established a research plan to investigate the aging and degradation processes associated with concrete used in NPPs. This paper outlines the research program including: 1) defining the upper bound of the neutron and gamma dose levels expected in the biological shield concrete for extended operation (80 years of operation and beyond), 2) determining the effects of neutron and gamma irradiation as well as extended time at temperature on concrete, 3) evaluating opportunities to irradiate prototypical concrete under accelerated neutron and gamma dose levels to establish a conservative bound and share data obtained from different flux, temperature, and fluence levels, 4) evaluating opportunities to harvest and test irradiated concrete from international NPPs, 5) developing cooperative test programs to improve confidence in the results from the various concretes and research reactors, 6) furthering the understanding of the effects of radiation on concrete and 7) establishing an international collaborative research and information exchange effort to leverage capabilities and knowledge

  12. LHCb: Radiation Damage in the LHCb VELO

    CERN Multimedia

    Rodriguez Perez, P

    2012-01-01

    LHCb is a dedicated experiment to study new physics in the decays of beauty and charm hadrons at the Large Hadron Collider (LHC) at CERN. The beauty and charm hadrons are identified through their flight distance in the Vertex Locator (VELO), and hence the detector is critical for both the trigger and offline physics analyses. The 88 VELO sensors are all n-on-n type but one, which is made from n-on-p silicon, and is the only n-on-p module silicon sensor operated at the LHC. The sensors have an inner radius of only 7 mm from the LHC beam and an outer radius of 42 mm, consequently the sensors receive a large and non-uniform radiation dose. The LHCb is planned to record an integrated luminosity up to 5 $fb^{-1}$ with collision energies between 7 and 14 TeV before 2018. The leakage current in the sensors has increased significantly following the delivered luminosity, and decreased during shutdown periods due to annealing. The effective depletion voltage of the sensors is measured from the charge collection effi...

  13. A new mechanism for radiation damage processes in alkali halides

    NARCIS (Netherlands)

    Dubinko, V.I.; Turkin, A.A.; Vainshtein, D.I.; Hartog, H.W. den

    1999-01-01

    We present a theory of radiation damage formation in alkali halides based on a new mechanism of dislocation climb, which involves the production of VF centers (self-trapped hole neighboring a cation vacancy) as a result of the absorption of H centers of dislocation lines. We consider the evolution o

  14. Genomic damage in children accidentally exposed to ionizing radiation

    DEFF Research Database (Denmark)

    Fucic, A; Brunborg, G; Lasan, R;

    2007-01-01

    after the Chernobyl nuclear plant accident in 1986. The present review presents and discusses data collected from papers analyzing genome damage in children environmentally exposed to ionizing radiation. Overall, the evidence from the studies conducted following the Chernobyl accident, nuclear tests...

  15. Macromolecular crystallography radiation damage research: what’s new?

    OpenAIRE

    Garman, Elspeth F.; Weik, Martin

    2011-01-01

    Radiation damage in macromolecular crystallography has become a mainstream concern over the last ten years. The current status of research into this area is briefly assessed, and the ten new papers published in this issue are set into the context of previous work in the field. Some novel and exciting developments emerging over the last two years are also summarized.

  16. Neutron dosimetry and radiation damage calculations for HFBR

    Energy Technology Data Exchange (ETDEWEB)

    Greenwood, L.R.; Ratner, R.T. [Pacific Northwest National Lab., TN (United States)

    1998-03-01

    Neutron dosimetry measurements have been conducted for various positions of the High Flux Beam Reactor (HFBR) at Brookhaven National Laboratory (BNL) in order to measure the neutron flux and energy spectra. Neutron dosimetry results and radiation damage calculations are presented for positions V10, V14, and V15.

  17. Radiation damage on the LHCb-VELO

    Energy Technology Data Exchange (ETDEWEB)

    Casse, G., E-mail: gcasse@hep.ph.liv.ac.uk

    2013-12-01

    The LHCb Vertex Locator (VELO) is designed to reconstruct charged particle trajectories and vertices produced at the LHCb interaction region. This is a silicon strip detector system operating at the closest distance from the interaction region among all the currently installed detectors at the CERN LHC. The geometry of the sensors implies that every detector region is exposed to a different dose of radiation depending mainly on the radial distance from the beam line. In the first 2 years of operation they have been exposed to a range of fluences up to a maximum value of about 4.5×10{sup 13} 1 MeV neutron equivalent (n{sub eq}) cm{sup −2}. At the end of 2012 a maximum of about 1.5×10{sup 14} n{sub eq} has been reached; data analysis is ongoing. Sensor currents, full depletion voltage and charge collection efficiencies have been studied at various fluences. Observation of type inversion of the n-type silicon sensors has been made (about after 10–15×10{sup 12} n{sub eq}). The n-type bulk sensors have been compared with the only p-type bulk detectors installed in the LHC. A reduction in the charge collection efficiency due to charge losses to a second metal layer (used for routing the signal to the readout electronics in LHCb-VELO sensors) has been measured. Possible solutions to this undesirable effect are planned to be studied in the framework of the LHCb-VELO upgrade.

  18. Radiation induced crystallinity damage in poly(L-lactic acid)

    International Nuclear Information System (INIS)

    The radiation-induced crystallinity damage in poly(L-lactic acid) (PLLA) in the presence of air and in vacuum, is studied. From the heat of fusion enthalpy values of gamma irradiated samples, some changes on the thermal properties were determined. To identify these changes, first the glass transition temperature (Tg) of L-lactic acid polymers irradiated to various doses in air and vacuum have been investigated and it is found that it is independent of irradiation atmosphere and dose. The fraction of damaged units of PLLA per unit of absorbed energy has been measured. For this purpose, SAXS and differential scanning calorimetry methods were used, and the radiation yield of number of damaged units (G(-u)) is found to be 0.74 and 0.58 for PLLA samples irradiated in vacuum and air, respectively

  19. Radiation induced crystallinity damage in poly(L-lactic acid)

    CERN Document Server

    Kantoglu, O

    2002-01-01

    The radiation-induced crystallinity damage in poly(L-lactic acid) (PLLA) in the presence of air and in vacuum, is studied. From the heat of fusion enthalpy values of gamma irradiated samples, some changes on the thermal properties were determined. To identify these changes, first the glass transition temperature (T sub g) of L-lactic acid polymers irradiated to various doses in air and vacuum have been investigated and it is found that it is independent of irradiation atmosphere and dose. The fraction of damaged units of PLLA per unit of absorbed energy has been measured. For this purpose, SAXS and differential scanning calorimetry methods were used, and the radiation yield of number of damaged units (G(-u)) is found to be 0.74 and 0.58 for PLLA samples irradiated in vacuum and air, respectively.

  20. Radiation damage and recovery of the immune system

    International Nuclear Information System (INIS)

    The objectives of the project are concentrated on the problems related to damage and recovery of the immune system after radiation exposure. Mouse populations were studied after whole-body exposure to acute x-ray doses ranging from 1 to 10 Gy. Untreated and treated survivors were studied to assess the number and activity of blood leukocytes and to evaluate the immune functions of spleen lymphocytes. Comparison of the effects of various treatments after different radiation doses should indicate the conditions for optimal intervention to accelerate recovery of the immune system and to prevent radiation death. (R.P.) 27 refs

  1. Cyclovirobuxine D Attenuates Doxorubicin-Induced Cardiomyopathy by Suppression of Oxidative Damage and Mitochondrial Biogenesis Impairment

    Directory of Open Access Journals (Sweden)

    Qian Guo

    2015-01-01

    Full Text Available The clinical application of doxorubicin (DOX is compromised by its cardiac toxic effect. Cyclovirobuxine D (CVB-D is a steroid alkaloid extracted from a traditional Chinese medicine, Buxus microphylla. Our results showed that CVB-D pretreatment markedly attenuated DOX-induced cardiac contractile dysfunction and histological alterations. By using TUNEL assay and western blot analysis, we found that CVB-D pretreatment reduced DOX-induced apoptosis of myocardial cells and mitochondrial cytochrome c release to cytosol. CVB-D pretreatment ameliorated DOX-induced cardiac oxidative damage including lipid peroxidation and protein carbonylation and a decrease in the ratio of reduced glutathione (GSH to oxidized glutathione (GSSG. Moreover, CVB-D was found to prevent DOX-induced mitochondrial biogenesis impairment as evidenced by preservation of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α and nuclear respiratory factor 1 (NRF1, as well as mitochondrial DNA copy number. These findings demonstrate that CVB-D protects against DOX-induced cardiomyopathy, at least in part, by suppression of oxidative damage and mitochondrial biogenesis impairment.

  2. Whey protein isolate attenuates strength decline after eccentrically-induced muscle damage in healthy individuals

    Directory of Open Access Journals (Sweden)

    Cribb Paul J

    2010-09-01

    Full Text Available Abstract Background We examined the effects of short-term consumption of whey protein isolate on muscle proteins and force recovery after eccentrically-induced muscle damage in healthy individuals. Methods Seventeen untrained male participants (23 ± 5 yr, 180 ± 6 cm, 80 ± 11 kg were randomly separated into two supplement groups: i whey protein isolate (WPH; n = 9; or ii carbohydrate (CHO; n = 8. Participants consumed 1.5 g/kg.bw/day supplement (~30 g consumed immediately, and then once with breakfast, lunch, in the afternoon and after the evening meal for a period of 14 days following a unilateral eccentric contraction-based resistance exercise session, consisting of 4 sets of 10 repetitions at 120% of maximum voluntary contraction on the leg press, leg extension and leg flexion exercise machine. Plasma creatine kinase and lactate dehydrogenase (LDH levels were assessed as blood markers of muscle damage. Muscle strength was examined by voluntary isokinetic knee extension using a Cybex dynamometer. Data were analyzed using repeated measures ANOVA with an alpha of 0.05. Results Isometric knee extension strength was significantly higher following WPH supplementation 3 (P Conclusions The major finding of this investigation was that whey protein isolate supplementation attenuated the impairment in isometric and isokinetic muscle forces during recovery from exercise-induced muscle injury.

  3. Introduction to neutron metrology for reactor radiation damage

    International Nuclear Information System (INIS)

    This document, prepared by members of the Irradiation Damage Subgroup of the Euratom Working Group on Reactor Dosimetry (EWGRD) describes the background of the procedures for determining irradiation parameters which are of interest in radiation damage experiments. The first two chapters outline the concept of damage functions and damge models. The next two chapters give information on methods to determine neutron fluences and neutron spectra. The fifth chapter gives a review of correlation data available for graphite and steels. The last chapter gives guidance how to report the relevant irradiation parameters. Attention is given to the role of the neutron spectrum in deriving values for damage fluence, energy transferred to the lattice, and number of displacements. A suggested list to report data relevant to the irradiation, the instrumentation and the testing of material is included

  4. Radiation damage studies for the DOe silicon detector

    Energy Technology Data Exchange (ETDEWEB)

    Lehner, Frank E-mail: lehnerf@physik.unizh.ch

    2004-09-01

    We report on irradiation studies performed on spare production silicon detector modules for the current DOe silicon detector. The lifetime expectations due to radiation damage effects of the existing silicon detector are reviewed. A new upgrade project was started with the goal of a complete replacement of the existing silicon detector. In that context, several investigations on the radiation hardness of new prototype silicon microstrip detectors were carried out. The irradiation on different detector types was performed with 10 MeV protons up to fluences of 10{sup 14} p/cm{sup 2} at the J.R. Mcdonald Laboratory at Kansas State University. The flux calibration was carefully checked using different normalisation techniques. As a result, we observe roughly 40-50% less radiation damage in silicon for 10 MeV p exposure than it is expected by the predicted NIEL scaling.

  5. Modelling radiation damage to ESA's Gaia satellite CCDs

    CERN Document Server

    Seabroke, G M; Cropper, M S

    2008-01-01

    The Gaia satellite is a high-precision astrometry, photometry and spectroscopic ESA cornerstone mission, currently scheduled for launch in late 2011. Its primary science drivers are the composition, formation and evolution of the Galaxy. Gaia will achieve its scientific requirements with detailed calibration and correction for radiation damage. Microscopic models of Gaia's CCDs are being developed to simulate the charge trapping effect of radiation damage, which causes charge transfer inefficiency. The key to calculating the probability of a photoelectron being captured by a trap is the 3D electron density within each CCD pixel. However, this has not been physically modelled for Gaia CCD pixels. In this paper, the first of a series, we motivate the need for such specialised 3D device modelling and outline how its future results will fit into Gaia's overall radiation calibration strategy.

  6. Temperature effects on radiation damage in plastic detectors

    International Nuclear Information System (INIS)

    The objective of present work was to study the temperature effect on radiation damage registration in the structure of a Solid State Nuclear Track Detector of the type CR-39. In order to study the radiation damage as a function of irradiation temperature, sheets of CR-39 detectors were irradiated with electron beams, simulating the interaction of positive ions. CR-39 detectors were maintained at a constant temperature from room temperature up to 373 K during irradiation. Two techniques were used from analyzing changes in the detector structure: Electronic Paramagnetic Resonance (EPR) and Infrared Spectroscopy (IR). It was found by EPR analysis that the amount of free radicals decrease as irradiation temperature increases. The IR spectrums show yield of new functional group identified as an hydroxyl group (OH). A proposed model of interaction of radiation with CR-39 detectors is discussed. (Author)

  7. Edaravone protects PC12 cells from ischemic-like injury via attenuating the damage to mitochondria

    Institute of Scientific and Technical Information of China (English)

    SONG Ying; LI Meng; LI Ji-cheng; WEI Er-qing

    2006-01-01

    Background: Edaravone had been validated to effectively protect against ischemic injuries. In this study, we investigated the protective effect of edaravone by observing the effects on anti-apoptosis, regulation of Bcl-2/Bax protein expression and recovering from damage to mitochondria after OGD (oxygen-glucose deprivation)-reperfusion. Methods: Viability of PC 12cells which were injured at different time of OGD injury, was quantified by measuring MTT (2-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) staining. In addition, PC 12 cells' viability was also quantified after their preincubation in different concentration of edaravone for 30 min followed by (OGD). Furthermore, apoptotic population of PC12 cells that reinsulted from OGD-reperfusion with or without preincubation with edaravone was determined by flow cytometer analysis,electron microscope and Hoechst/PI staining. Finally, change of Bcl-2/Bax protein expression was detected by Westem blot.Results: (1) The viability of PC 12 cells decreased with time (1~12 h) after OGD. We regarded the model of OGD 2 h, then replacing DMEM (Dulbecco's Modified Eagle's Medium) for another 24 h as an OGD-reperfusion in this research. Furthermore,most PC12 cells were in the state of apoptosis after OGD-reperfusion. (2) The viability of PC12 cells preincubated with edaravone at high concentrations (1,0.1, 0.01 μmol/L) increased significantly with edaravone protecting PC 12 cells from apoptosis after OGD-reperfusion injury. (3) Furthermore, edaravone attenuates the damage of OGD-reperfusion on mitochondria and regulated Bcl-2/Bax protein imbalance expression after OGD-reperfusion. Conclusion: Neuroprotective effects of edaravone on ischemic or other brain injuries may be partly mediated through inhibition of Bcl-2/Bax apoptotic pathways by recovering from the damage of mitochondria.

  8. Edaravone attenuates brain damage in rats after acute CO poisoning through inhibiting apoptosis and oxidative stress.

    Science.gov (United States)

    Li, Qin; Bi, Ming Jun; Bi, Wei Kang; Kang, Hai; Yan, Le Jing; Guo, Yun-Liang

    2016-03-01

    Acute carbon monoxide (CO) poisoning is the most common cause of death from poisoning all over the world and may result in neuropathologic and neurophysiologic changes. Acute brain damage and delayed encephalopathy are the most serious complication, yet their pathogenesis is poorly understood. The present study aimed to evaluate the neuroprotective effects of Edaravone against apoptosis and oxidative stress after acute CO poisoning. The rat model of CO poisoning was established in a hyperbaric oxygen chamber by exposed to CO. Ultrastructure changes were observed by transmission electron microscopy (TEM). TUNEL stain was used to assess apoptosis. Immunohistochemistry and immunofluorescence double stain were used to evaluate the expression levels of heme oxygenase-1 (HO-1) and nuclear factor erythroid 2-related factor 2 (Nrf-2) protein and their relationship. By dynamically monitored the carboxyhemoglobin (HbCO) level in blood, we successfully established rat model of severe CO poisoning. Ultrastructure changes, including chromatin condensation, cytoplasm dissolution, vacuoles formation, nucleus membrane and cell organelles decomposition, could be observed after CO poisoning. Edaravone could improve the ultrastructure damage. CO poisoning could induce apoptosis. Apoptotic cells were widely distributed in cortex, striatum and hippocampus. Edaravone treatment attenuated neuronal apoptosis as compared with the poisoning group (P < 0.01). Basal expressions of HO-1 and Nrf-2 proteins were found in normal brain tissue. CO poisoning could activate HO-1/Nrf-2 pathway, start oxidative stress response. After the administration of Edaravone, the expression of HO-1 and Nrf-2 significantly increased (P < 0.01). These findings suggest that Edaravone may inhibit apoptosis, activate the Keapl-Nrf/ARE pathway, and thus improve the ultrastructure damage and neurophysiologic changes following acute CO poisoning. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 372-379, 2016

  9. Aerosols attenuating the solar radiation collected by solar tower plants: The horizontal pathway at surface level

    Science.gov (United States)

    Elias, Thierry; Ramon, Didier; Dubus, Laurent; Bourdil, Charles; Cuevas-Agulló, Emilio; Zaidouni, Taoufik; Formenti, Paola

    2016-05-01

    Aerosols attenuate the solar radiation collected by solar tower plants (STP), along two pathways: 1) the atmospheric column pathway, between the top of the atmosphere and the heliostats, resulting in Direct Normal Irradiance (DNI) changes; 2) the grazing pathway close to surface level, between the heliostats and the optical receiver. The attenuation along the surface-level grazing pathway has been less studied than the aerosol impact on changes of DNI, while it becomes significant in STP of 100 MW or more. Indeed aerosols mostly lay within the surface atmospheric layer, called the boundary layer, and the attenuation increases with the distance covered by the solar radiation in the boundary layer. In STP of 100 MW or more, the distance between the heliostats and the optical receiver becomes large enough to produce a significant attenuation by aerosols. We used measured aerosol optical thickness and computed boundary layer height to estimate the attenuation of the solar radiation at surface level at Ouarzazate (Morocco). High variabilities in aerosol amount and in vertical layering generated a significant magnitude in the annual cycle and significant inter-annual changes. Indeed the annual mean of the attenuation caused by aerosols over a 1-km heliostat-receiver distance was 3.7% in 2013, and 5.4% in 2014 because of a longest desert dust season. The monthly minimum attenuation of less than 3% was observed in winter and the maximum of more than 7% was observed in summer.

  10. Attenuation of solar ultraviolet radiation in eutrophic freshwater lakes and ponds

    International Nuclear Information System (INIS)

    Vertical attenuation of underwater ultraviolet radiation [UVR; UVA (320-400 nm) and UVB (280-315 nm) together with photo-synthetically available radiation (PAR, 400-700 nm)] was measured at 22 sites from 5 freshwater bodies of various trophic states. The factors controlling the attenuation of UVR were examined. At all the sites, underwater irradiances decreased almost exponentially with depth and were more attenuated in dimension order from UVB, UVA, to PAR. Substantial variation in attenuation was observed among water bodies. Attenuation depths (Z1%) for UVB ranged from 0.3 m to 1 m in the eutrophic sites, while exceeding 2 m in oligo-mesotrophic ones. Z1% of UVB and that of UVA were 0.5 and 0.9 times the Secchi disk depth, respectively. Attenuation coefficients (m-1) of UVA and UVB showed significantly positive linear correlations with both chlorophyll a and particulate organic carbon concentrations. Dissolved organic carbon (DOC) was weakly correlated with attenuation coefficients of UVA and UVB. This disagrees with previous reports that stated DOC is the major factor controlling underwater UVR. Phytoplankton is considered to be the more important factor controlling the attenuation of underwater UVR in water bodies with high phytoplankton content and low DOC. (author)

  11. Attenuation of VHE Gamma Rays by the Milky Way Interstellar Radiation Field

    Energy Technology Data Exchange (ETDEWEB)

    Moskalenko, Igor V.; /Stanford U., HEPL; Porter, Troy A.; /Louisiana State U.; Strong, Andrew W.; /Garching, Max Planck Inst., MPE

    2006-04-19

    The attenuation of very high energy gamma rays by pair production on the Galactic interstellar radiation field has long been thought of as negligible. However, a new calculation of the interstellar radiation field consistent with multi-wavelength observations by DIRBE and FIRAS indicates that the energy density of the Galactic interstellar radiation field is higher, particularly in the Galactic center, than previously thought. We have made a calculation of the attenuation of very high energy gamma rays in the Galaxy using this new interstellar radiation field which takes into account its nonuniform spatial and angular distributions. We find that the maximum attenuation occurs around 100 TeV at the level of about 25% for sources located at the Galactic center, and is important for both Galactic and extragalactic sources.

  12. Proton-induced radiation damage in germanium detectors

    Science.gov (United States)

    Brueckner, J.; Koerfer, M.; Waenke, H.; Schroeder, A. N. F.; Filges, D.; Dragovitsch, P.; Englert, P. A. J.; Starr, R.; Trombka, J. I.

    1991-01-01

    High-purity germanium (HPGe) detectors will be used in future space missions for gamma-ray measurements and will be subject to interactions with energetic particles. To simulate this process, several large-volume n-type HPGe detectors were incrementally exposed to a particle fluence of up to 10 to the 8th protons/sq cm (proton energy: 1.5 GeV) at different operating temperatures (90 to 120 K) to induce radiation damage. Basic scientific and engineering data on detector performance were collected. During the incremental irradiation, the peak shape produced by the detectors showed a significant change from a Gaussian shape to a broad complex structure. After the irradiation, all detectors were thoroughly characterized by measuring many parameters. To remove the accumulated radiation damage, the detectors were stepwise-annealed at temperatures below 110 C, while kept in their specially designed cryostats. This study shows that n-type HPGe detectors can be used in charged-particle environments as high-energy resolution devices until a certain level of radiation damage is accumulated and that the damage can be removed at moderate annealing temperatures and the detector returned to operating condition.

  13. Radiation damage in natural materials: implications for radioactive waste forms

    International Nuclear Information System (INIS)

    The long-term effect of radiation damage on waste forms, either crystalline or glass, is a factor in the evaluation of the integrity of waste disposal mediums. Natural analogs, such as metamict minerals, provide one approach for the evaluaton of radiation damage effects that might be observed in crystalline waste forms, such as supercalcine or synroc. Metamict minerals are a special class of amorphous materials which were initially crystalline. Although the mechanism for the loss of crystallinity in these minerals (mostly actinide-containing oxides and silicates) is not clearly understood, damage caused by alpha particles and recoil nuclei is critical to the metamictization process. The study of metamict minerals allows the evaluation of long-term radiation damage effects, particularly changes in physical and chemical properties such as microfracturing, hydrothermal alteration, and solubility. In addition, structures susceptible to metamictization share some common properties: (1) complex compositions; (2) some degree of covalent bonding, instead of being ionic close-packed MO/sub x/ structures; and (3) channels or interstitial voids which may accommodate displaced atoms or absorbed water. On the basis of these empirical criteria, minerals such as pollucite, sodalite, nepheline and leucite warrant careful scrutiny as potential waste form phases. Phases with the monazite or fluorite structures are excellent candidates

  14. Compilation of radiation damage test data. Pt. 3

    International Nuclear Information System (INIS)

    This handbook gives the results of radiation damage tests on various engineering materials and components intended for installation in radiation areas of the CERN high-energy particle accelerators. It complements two previous volumes covering organic cable-insulating materials and thermoplastic and thermosetting resins. The irradiation have been carried out at various radiation sources and the results of the different tests are reported, sometimes illustrated by tables and graphs to show the variation of the measured property with absorbed radiation dose. For each entry, an appreciation of the radiation resistance is given, based on measurement data, indicating the range of damage (moderate to severe) for doses from 10 to 108 Gy. Also included are tables, selected from published reports, of general relative radiation effects for several groups of materials, to which there are systematic cross-references in the alphabetical part. This third and last volume contains cross-references to all the materials presented up to now, so that it can be used as a guide to the three volumes. (orig.)

  15. Accuracy and Radiation Dose of CT-Based Attenuation Correction for Small Animal PET: A Monte Carlo Simulation Study

    International Nuclear Information System (INIS)

    -Small animal PET allows qualitative assessment and quantitative measurement of biochemical processes in vivo, but the accuracy and reproducibility of imaging results can be affected by several parameters. The first aim of this study was to investigate the performance of different CT-based attenuation correction strategies and assess the resulting impact on PET images. The absorbed dose in different tissues caused by scanning procedures was also discussed to minimize biologic damage generated by radiation exposure due to PET/CT scanning. A small animal PET/CT system was modeled based on Monte Carlo simulation to generate imaging results and dose distribution. Three energy mapping methods, including the bilinear scaling method, the dual-energy method and the hybrid method which combines the kVp conversion and the dual-energy method, were investigated comparatively through assessing the accuracy of estimating linear attenuation coefficient at 511 keV and the bias introduced into PET quantification results due to CT-based attenuation correction. Our results showed that the hybrid method outperformed the bilinear scaling method, while the dual-energy method achieved the highest accuracy among the three energy mapping methods. Overall, the accuracy of PET quantification results have similar trend as that for the estimation of linear attenuation coefficients, whereas the differences between the three methods are more obvious in the estimation of linear attenuation coefficients than in the PET quantification results. With regards to radiation exposure from CT, the absorbed dose ranged between 7.29-45.58 mGy for 50-kVp scan and between 6.61-39.28 mGy for 80-kVp scan. For 18F radioactivity concentration of 1.86x105 Bq/ml, the PET absorbed dose was around 24 cGy for tumor with a target-to-background ratio of 8. The radiation levels for CT scans are not lethal to the animal, but concurrent use of PET in longitudinal study can increase the risk of biological effects. The

  16. Monitoring Radiation Damage in the ATLAS Pixel Detector

    CERN Document Server

    Schorlemmer, André Lukas; Große-Knetter, Jörn; Rembser, Christoph; Di Girolamo, Beniamino

    2014-11-05

    Radiation hardness is one of the most important features of the ATLAS pixel detector in order to ensure a good performance and a long lifetime. Monitoring of radiation damage is crucial in order to assess and predict the expected performance of the detector. Key values for the assessment of radiation damage in silicon, such as the depletion voltage and depletion depth in the sensors, are measured on a regular basis during operations. This thesis summarises the monitoring program that is conducted in order to assess the impact of radiation damage and compares it to model predictions. In addition, the physics performance of the ATLAS detector highly depends on the amount of disabled modules in the ATLAS pixel detector. A worrying amount of module failures was observed during run I. Thus it was decided to recover repairable modules during the long shutdown (LS1) by extracting the pixel detector. The impact of the module repairs and module failures on the detector performance is analysed in this thesis.

  17. Radiation damage in CaF2: Gd

    International Nuclear Information System (INIS)

    Calcium fluoride crystals doped with Gd3+ at four different concentrations were irradiated at room temperature. The damage produced by radiation and the primary and secondary effects as well were studied by optical spectroscopy. The increase in optical absorption (with loss of transparency) varied from sample as a function of concentration and dose. The coloration curves showed an evolution from two to three radiation damage steps when going from a pure to the most Gd3+ concentrated sample. The obtained spectra were analysed at characteristic wave lenghts of electronic defects (photochromic centers, F and its aggregates) and of Gd3+ and Gd2+ defects. As a result of the radiation damage the valence change (Gd3+→Gd2+) and its reversible character under thermal activation were directly observed. These effects were correlated with other observed effects such as the room temperature luminescence after the irradiation ceased. The non radiative F centers formation from the interaction of holes and photochromic centers was also observed and analysed. A thermal activation study of the several defects responsible for the different absorption bands was made. Values of activation energies were obtained as expected for the kind of defects involved in these processes

  18. Experimental determination of radiation damage function for graphite

    International Nuclear Information System (INIS)

    Highly oriented pyrolytic-graphite samples were irradiated in three different neutron sources with average energies of 1.5, 5.5, and 14.8 MeV, respectively. The resulting changes in the basal-plane elastic shear moduli of these samples show that the relative damage rate is substantially higher at the higher neutron energies than is predicted by existing models. The results of these experiments have been used to generate a new relative damage function which will allow better projections of graphite radiation behavior in fusion reactors based on data obtained by irradiations in fission reactors

  19. Attenuation and cross-attenuation in taste aversion learning in the rat: Studies with ionizing radiation, lithium chloride and ethanol

    International Nuclear Information System (INIS)

    The preexposure paradigm was utilized to evaluate the similarity of ionizing radiation, lithium chloride and ethanol as unconditioned stimuli for the acquisition of a conditioned taste aversion. Three unpaired preexposures to lithium chloride (3.0 mEq/kg, IP) blocked the acquisition of a taste aversion when a novel sucrose solution was paired with either the injection of the same dose of lithium chloride or exposure to ionizing radiation (100 rad). Similar pretreatment with radiation blocked the acquisition of a radiation-induced aversion, but had no effect on taste aversions produced by lithium chloride (3.0 or 1.5 mEq/kg). Preexposure to ethanol (4 g/kg, PO) disrupted the acquisition of an ethanol-induced taste aversion, but not radiation- or lithium chloride-induced aversions. In contrast, preexposure to either radiation or lithium chloride attenuated an ethanol-induced taste aversion in intact rats, but not in rats with lesions of the area postrema. The results are discussed in terms of relationships between these three unconditioned stimuli and in terms of implications of these results for understanding the nature of the proximal unconditioned stimulus in taste aversion learning

  20. DNA damage induced by the direct effect of radiation

    Science.gov (United States)

    Yokoya, A.; Shikazono, N.; Fujii, K.; Urushibara, A.; Akamatsu, K.; Watanabe, R.

    2008-10-01

    We have studied the nature of DNA damage induced by the direct effect of radiation. The yields of single- (SSB) and double-strand breaks (DSB), base lesions and clustered damage were measured using the agarose gel electrophoresis method after exposing to various kinds of radiations to a simple model DNA molecule, fully hydrated closed-circular plasmid DNA (pUC18). The yield of SSB does not show significant dependence on linear energy transfer (LET) values. On the other hand, the yields of base lesions revealed by enzymatic probes, endonuclease III (Nth) and formamidopyrimidine DNA glycosylase (Fpg), which excise base lesions and leave a nick at the damage site, strongly depend on LET values. Soft X-ray photon (150 kVp) irradiation gives a maximum yield of the base lesions detected by the enzymatic probes as SSB and clustered damage, which is composed of one base lesion and proximate other base lesions or SSBs. The clustered damage is visualized as an enzymatically induced DSB. The yields of the enzymatically additional damages strikingly decrease with increasing levels of LET. These results suggest that in higher LET regions, the repair enzymes used as probes are compromised because of the dense damage clustering. The studies using simple plasmid DNA as a irradiation sample, however, have a technical difficulty to detect multiple SSBs in a plasmid DNA. To detect the additional SSBs induced in opposite strand of the first SSB, we have also developed a novel technique of DNA-denaturation assay. This allows us to detect multiply induced SSBs in both strand of DNA, but not induced DSB.

  1. Involvement of inducible nitric oxide synthase in radiation-induced vascular endothelial damage

    International Nuclear Information System (INIS)

    The use of radiation therapy has been linked to an increased risk of cardiovascular disease. To understand the mechanisms underlying radiation-induced vascular dysfunction, we employed two models. First, we examined the effect of X-ray irradiation on vasodilation in rabbit carotid arteries. Carotid arterial rings were irradiated with 8 or 16 Gy using in vivo and ex vivo methods. We measured the effect of acetylcholine-induced relaxation after phenylephrine-induced contraction on the rings. In irradiated carotid arteries, vasodilation was significantly attenuated by both irradiation methods. The relaxation response was completely blocked by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, a potent inhibitor of soluble guanylate cyclase. Residual relaxation persisted after treatment with L-Nω-nitroarginine (L-NA), a non-specific inhibitor of nitric oxide synthase (NOS), but disappeared following the addition of aminoguanidine (AG), a selective inhibitor of inducible NOS (iNOS). The relaxation response was also affected by tetraethylammonium, an inhibitor of endothelium-derived hyperpolarizing factor activity. In the second model, we investigated the biochemical events of nitrosative stress in human umbilical-vein endothelial cells (HUVECs). We measured iNOS and nitrotyrosine expression in HUVECs exposed to a dose of 4 Gy. The expression of iNOS and nitrotyrosine was greater in irradiated HUVECs than in untreated controls. Pretreatment with AG, L-N6-(1-iminoethyl) lysine hydrochloride (a selective inhibitor of iNOS), and L-NA attenuated nitrosative stress. While a selective target of radiation-induced vascular endothelial damage was not definitely determined, these results suggest that NO generated from iNOS could contribute to vasorelaxation. These studies highlight a potential role of iNOS inhibitors in ameliorating radiation-induced vascular endothelial damage. (author)

  2. Radiative Transfer Model of Dust Attenuation Curves in Clumpy, Galactic Environments

    CERN Document Server

    Seon, Kwang-Il

    2016-01-01

    The attenuation of starlight by dust in galactic environments is investigated through models of radiative transfer in a spherical, clumpy ISM. Extinction properties for MW, LMC, and SMC dust types are considered. It is illustrated that the attenuation curves are primarily determined by the wavelength dependence of absorption rather than by the underlying extinction (absorption+scattering) curve. Attenuation curves consistent with the "Calzetti attenuation curve" are found by assuming the silicate-carbonaceous dust model for the MW, but with the 2175A absorption bump suppressed or absent. The discrepancy between our results and previous work that claimed the SMC-type dust to be the most likely origin of the Calzetti curve is ascribed to the difference in adopted albedos; this study uses the theoretically calculated albedos whereas the previous ones adopted empirically derived albedos from observations of reflection nebulae. It is also found that the model attenuation curves calculated with the MW dust are well...

  3. Clarithromycin Attenuates Radiation-Induced Lung Injury in Mice

    OpenAIRE

    Lee, Seung Jun; Yi, Chin-ok; Heo, Rok Won; Song, Dae Hyun; Cho, Yu Ji; Jeong, Yi Yeong; Kang, Ki Mun; Roh, Gu Seob; Lee, Jong Deog

    2015-01-01

    Radiation-induced lung injury (RILI) is a common and unavoidable complication of thoracic radiotherapy. The current study was conducted to evaluate the ability of clarithromycin (CLA) to prevent radiation-induced pneumonitis, oxidative stress, and lung fibrosis in an animal model. C57BL/6J mice were assigned to control, irradiation only, irradiation plus CLA, and CLA only groups. Test mice received single thoracic exposures to radiation and/or oral CLA (100 mg/kg/day). Histopathologic finding...

  4. Sesamol attenuates cytogenetic damages in bone marrow cells of whole body gamma irradiated mice

    International Nuclear Information System (INIS)

    Whole body radiation exposure cause damages to all vital organs and bone marrow is the most sensitive. Pre-treatment with antioxidant as single prophylactic dose is expected to lower induction of damages in bone marrow. In the present study we have focused on sesamol, a dietary antioxidant mediated radioprotection in bone marrow cells of gamma irradiated mice and compared with melatonin. Male C57BL/6 mice were intraperitoneally administered with sesamol (10 and 20 mg/kg body) and after 30 minutes exposed to whole body gamma radiation using 60Co Teletherapy unit. Mice were injected with 0.2 ml of a metaphase arresting agent (0.05% colchicine) intra-peritoneally 3 hours prior to sacrifice (24 hrs. post-irradiation). Bone marrow cells were flushed out from femurs of each animal and processed for chromosomal aberration assay. Another set of experiment without colchicine injection was performed to access the DNA damage in bone marrow using alkaline comet assay. At least 100 metaphases per animal were scored under light microscope to record various aberrations and total chromosomal aberrations (TCA) was calculated. Similar measurements were performed with melatonin for comparing the efficacy of sesamol. Gamma irradiation has increased the chromatid type aberrations (break formation, fragment) and chromosomal type aberrations (ring formation, acentric) in bone marrow cells. The results have shown significant (p< 0.001) increase in TCA of irradiated mice than control. While pre-treatment of sesamol and melatonin 10 mg/kg significantly (p<0.05) reduced the TCA. The extend of protection has increased at 20 mg/kg significantly (p<0.001) as evident from the reduced TCA compared to irradiated group. Interestingly, sesamol and melatonin have shown similar extent of reduction of TCA. Thus sesamol has demonstrated strong ability to protect bone marrow at low dosage. These investigations on sesamol mediated protection in bone marrow are likely to benefit development of

  5. Calculation of radiation attenuation coefficients for shielding concretes

    International Nuclear Information System (INIS)

    Theoretical calculations have been performed in order to obtain the mass attenuation coefficients and the linear attenuation coefficients at photon energies from 10 keV to 1 GeV for ordinary, hematite-serpentine, ilmenite-limonite, basalt-magnetite, ilmenite, steel-scrap and steel-magnetite concretes. The concrete densities ranged from 2.3 to 5.11 g cm-3. The calculated values of linear attenuation coefficients have been compared with those measured at gamma ray energies from 1.5 to 6 MeV for the concretes under investigation. Agreement between measured and calculated values has been obtained. Also, the fast neutron effective macroscopic removal cross-sections for the seven types of concrete have been calculated using the elemental composition of the mixes. Comparison between the measured and calculated effective removal cross-section values show a reasonable agreement for all types of concrete. Steel-magnetite concrete of high density (5.11 g cm-3), and with constituents of relatively high atomic number, is an effective shield for both photons and neutrons. (author)

  6. Protection from ionizing radiation induced damages by phytoceuticals and nutraceuticals

    International Nuclear Information System (INIS)

    Exposure of living systems to ionizing radiation cause a variety of damages to DNA and membranes due to generation of free radicals and reactive oxygen species. The radiation induced lesions in the cellular DNA are mainly strand breaks, damage to sugar moiety, alterations and elimination of bases, cross links of the intra and inter strand type and cross links to proteins while peroxidation of the lipids and oxidation of proteins constitute the major lesions in the membranes. The radioprotectors elicit their action by various mechanisms such as i) by suppressing the formation of reactive species, ii) detoxification of radiation induced species, iii) target stabilization and iv) enhancing the repair and recovery processes. The radioprotective compounds are of importance in medical, industrial, environmental, military and space science applications. Radiation protection might offer a tactical advantage on the battlefield in the event of a nuclear warfare. Radioprotectors might reduce the cancer risk to populations exposed to radiations directly or indirectly through industrial and military applications. The antioxidant and radioprotective properties a few of these agents under in vitro and in vivo conditions in animal models will be discussed

  7. Extreme radiation damage in soil from Mare Fecunditatis.

    Science.gov (United States)

    Phakey, P. P.; Price, P. B.

    1972-01-01

    High-voltage electron microscopy has been used to compare radiation effects in micron-size soil grains from the Luna 16 site (Mare Fecunditatis) and the four Apollo landing sites. Radiation damage by heavy solar particles is strikingly greater in the Luna 16 sample than in the other four samples. It is suggested that less movement of the soil at Mare Fecunditatis has taken place, perhaps because of its proximity to the limb and consequent lower exposure to energetic electrons in the earth's magnetospheric tail, which would cause electrostatic agitation of fine particles.

  8. Proton induced radiation damage in fast crystal scintillators

    Science.gov (United States)

    Yang, Fan; Zhang, Liyuan; Zhu, Ren-Yuan; Kapustinsky, Jon; Nelson, Ron; Wang, Zhehui

    2016-07-01

    This paper reports proton induced radiation damage in fast crystal scintillators. A 20 cm long LYSO crystal, a 15 cm long CeF3 crystal and four liquid scintillator based sealed quartz capillaries were irradiated by 800 MeV protons at Los Alamos up to 3.3 ×1014 p /cm2. Four 1.5 mm thick LYSO plates were irradiated by 24 GeV protons at CERN up to 6.9 ×1015 p /cm2. The results show an excellent radiation hardness of LYSO crystals against charged hadrons.

  9. Radiation damage in MOS varactors at low temperatures

    International Nuclear Information System (INIS)

    A description of the build-up of charges at low temperatures (T = 80 K) in SiO2 (MOS-structures) induced by ionizing radiation is presented. The damage is characterized by CV measurements and an expanded analysis is developed. A non-homogeneous distribution of frozen holes in the SiO2 appears corresponding to the energy deposition. When the radiation is terminated a field dependent (≥ 2 MV/cm) hole transport to the interfaces is observed. Only after warming (T ≥ 240 K) the structure interface states are created. (orig./HP)

  10. A stochastic model of radiation-induced bone marrow damage

    Energy Technology Data Exchange (ETDEWEB)

    Cotlet, G.; Blue, T.E.

    2000-03-01

    A stochastic model, based on consensus principles from radiation biology, is used to estimate bone-marrow stem cell pool survival (CFU-S and stroma cells) after irradiation. The dose response model consists of three coupled first order linear differential equations which quantitatively describe time dependent cellular damage, repair, and killing of red bone marrow cells. This system of differential equations is solved analytically through the use of a matrix approach for continuous and fractionated irradiations. The analytic solutions are confirmed through the dynamical solution of the model equations using SIMULINK. Rate coefficients describing the cellular processes of radiation damage and repair, extrapolated to humans from animal data sets and adjusted for neutron-gamma mixed fields, are employed in a SIMULINK analysis of criticality accidents. The results show that, for the time structures which may occur in criticality accidents, cell survival is established mainly by the average dose and dose rate.

  11. Ion irradiation and biomolecular radiation damage II. Indirect effect

    CERN Document Server

    Wang, Wei; Su, Wenhui

    2010-01-01

    It has been reported that damage of genome in a living cell by ionizing radiation is about one-third direct and two-thirds indirect. The former which has been introduced in our last paper, concerns direct energy deposition and ionizing reactions in the biomolecules; the latter results from radiation induced reactive species (mainly radicals) in the medium (mainly water) surrounding the biomolecules. In this review, a short description of ion implantation induced radical formation in water is presented. Then we summarize the aqueous radical reaction chemistry of DNA, protein and their components, followed by a brief introduction of biomolecular damage induced by secondary particles (ions and electron). Some downstream biological effects are also discussed.

  12. Radiation damage to biological macromolecules: some answers and more questions

    International Nuclear Information System (INIS)

    Research into radiation damage in macromolecular crystallography has matured over the last few years, resulting in a better understanding of both the processes and timescales involved. In turn this is now allowing practical recommendations for the optimization of crystal dose lifetime to be suggested. Some long-standing questions have been answered by recent investigations, and from these answers new challenges arise and areas of investigation can be proposed. Six papers published in this volume give an indication of some of the current directions of this field and also that of single-particle cryo-microscopy, and the brief summary below places them into the overall framework of ongoing research into macromolecular crystallography radiation damage. (authors)

  13. Genetics of repair of radiation damage to DNA in bacteria

    International Nuclear Information System (INIS)

    The goal of this project is to study the consequences to bacterial DNA of damage by radiation and chemical agents. By correlating the extent of physical and biological damage to DNA, as expressed in various mutants defective in specific DNA repair pathways, we hope to determine mechanisms of biological inactivation of DNA and ways in which the damage can be repaired. We have measured physical damage to DNA in Bacillus subtilis and Escherichia coli by use of alkaline sucrose gradient centrifugation, which indicates the distance between breaks or alkali-labile lesions in single strands of DNA. Biological damage is measured by loss of viability or by loss of transforming activity in treated DNA from B. subtilis, and by the production of sites for DNA repair synthesis by DNA polymerase I (Pol I) in toluene-treated E. coli. We have investigated effects of ultraviolet light (both far-uv and near-uv), ionizing radiation, and selected chemical agents, in the presence or absence of sensitizing or protective agents. A major goal was to characterize DNA repair processes in vivo in B. subtilis. A number of radiation-sensitive mutants were studied, with the result that we have learned a great many details about the repair of DNA in uv-irradiated cells: We have now also studied the induction of methyltransferase in B. subtilis exposed to low concentrations of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). In collaboration with Sankar Mitra and R.S. Foote (Biology Division), we have shown that the basal level of methyltransferase in B. subtilis is about ten-fold higher than in E. coli and that there is about a ten-fold increase during adaptation. Our future studies will focus on the radioprotective effects of alcohols that act as OH radical scavengers but also react to irradiation by the formation of a radical on the carbon alpha to the hydroxyl

  14. HSP25 Protects Radiation-Induced Salivary Gland Damage

    International Nuclear Information System (INIS)

    Irradiation (IR) is a central treatment modality administered for head and neck malignancies. A significant consequence of this IR treatment is irreversible damage to salivary gland in the IR field. While the exact mechanism of salivary gland damage remains enigmatic, fluid secreting acinar cells are lost, and saliva output is dramatically reduced. Previously we have reported that heat shock protein 25 (HSP25) induced radioresistance in vitro. HSP25 interferes negatively with apoptosis through several pathways which involve its direct interaction with cytochrome c, protein kinase c delta or Akt. And localized gene transfer to salivary glands has great potential for the treatment of salivary gland. Herein, we investigated whether HSP25 can use as radio protective molecules for radiation-induced salivary gland damage in vivo

  15. The LHCb Vertex Locator – Performance and Radiation Damage

    CERN Document Server

    Oblakowska-Mucha, A

    2014-01-01

    LHCb is a dedicated flavour physics experiment at the Large Hadron Collider at CERN. The Vertex Locator (VELO) is an important part of a LHCb tracking system, enabling precision measurement of beauty and charm mesons’ flight distance. The VELO consist of a set of silicon micro-strip detectors, arranged in two retractable halves, operating only 7 mm from the interac- tion region. In these proceedings the VELO performance during the Run 1 is summarised and radiation damage studies are presented.

  16. Red Palm Oil Attenuates Lead Acetate Induced Testicular Damage in Adult Male Sprague-Dawley Rats

    Directory of Open Access Journals (Sweden)

    A. I. Jegede

    2015-01-01

    Full Text Available To study the protective effect of Red Palm Oil (RPO on testicular damage induced by administration of lead acetate on male Sprague-Dawley rats, 28 rats divided into four groups of 7 animals each were used. They were administered orally with RPO (1 mL and 2 mL and lead acetate (i.p. 6 mg/kg body weight/day, respectively. Treatment was conducted for 8 weeks, and 24 hrs after the last treatment the rats were sacrificed using cervical dislocation. Sperms collected from epididymis were used for seminal fluid analyses; while the testes sample was used for ROS and oxidative enzyme activities assessment. Statistical analysis was carried out using GraphPad Prism 5.02 statistical analysis package. Administration of lead acetate increased generation of reactive oxygen species (ROS significantly (p<0.05 as evidenced by the elevated value of H2O2 and LPO and decreased GSH level. Also there was reduced epididymal sperm count, poor grade of sperm motility, and lower percentage of normal sperm morphology significantly. Coadministration with RPO, however, has a protective effect against lead toxicity by decreasing H2O2 production, increased GSH level, and increased sperm qualities especially. This shows that RPO has a potential to attenuate the toxic effect of lead on testicular cells preventing possible resultant male infertility.

  17. Red Palm Oil Attenuates Lead Acetate Induced Testicular Damage in Adult Male Sprague-Dawley Rats

    Science.gov (United States)

    Jegede, A. I.; Offor, U.; Azu, O. O.; Akinloye, O.

    2015-01-01

    To study the protective effect of Red Palm Oil (RPO) on testicular damage induced by administration of lead acetate on male Sprague-Dawley rats, 28 rats divided into four groups of 7 animals each were used. They were administered orally with RPO (1 mL and 2 mL) and lead acetate (i.p.) 6 mg/kg body weight/day, respectively. Treatment was conducted for 8 weeks, and 24 hrs after the last treatment the rats were sacrificed using cervical dislocation. Sperms collected from epididymis were used for seminal fluid analyses; while the testes sample was used for ROS and oxidative enzyme activities assessment. Statistical analysis was carried out using GraphPad Prism 5.02 statistical analysis package. Administration of lead acetate increased generation of reactive oxygen species (ROS) significantly (p < 0.05) as evidenced by the elevated value of H2O2 and LPO and decreased GSH level. Also there was reduced epididymal sperm count, poor grade of sperm motility, and lower percentage of normal sperm morphology significantly. Coadministration with RPO, however, has a protective effect against lead toxicity by decreasing H2O2 production, increased GSH level, and increased sperm qualities especially. This shows that RPO has a potential to attenuate the toxic effect of lead on testicular cells preventing possible resultant male infertility. PMID:26516332

  18. Brazilian red propolis attenuates hypertension and renal damage in 5/6 renal ablation model.

    Directory of Open Access Journals (Sweden)

    Flávio Teles

    Full Text Available The pathogenic role of inflammation and oxidative stress in chronic kidney disease (CKD is well known. Anti-inflammatories and antioxidant drugs has demonstrated significant renoprotection in experimental nephropathies. Moreover, the inclusion of natural antioxidants derived from food and herbal extracts (such as polyphenols, curcumin and lycopene as an adjuvant therapy for slowing CKD progression has been largely tested. Brazilian propolis is a honeybee product, whose anti-inflammatory, antimicrobial and antioxidant effects have been widely shown in models of sepsis, cancer, skin irritation and liver fibrosis. Furthermore, previous studies demonstrated that this compound promotes vasodilation and reduces hypertension. However, potential renoprotective effects of propolis in CKD have never been investigated. The aim of this study was to evaluate the effects of a subtype of Brazilian propolis, the Red Propolis (RP, in the 5/6 renal ablation model (Nx. Adult male Wistar rats underwent Nx and were divided into untreated (Nx and RP-treated (Nx+RP groups, after 30 days of surgery; when rats already exhibited marked hypertension and proteinuria. Animals were observed for 90 days from the surgery day, when Nx+RP group showed significant reduction of hypertension, proteinuria, serum creatinine retention, glomerulosclerosis, renal macrophage infiltration and oxidative stress, compared to age-matched untreated Nx rats, which worsened progressively over time. In conclusion, RP treatment attenuated hypertension and structural renal damage in Nx model. Reduction of renal inflammation and oxidative stress could be a plausible mechanism to explain this renoprotection.

  19. Inhibition of Epidermal Growth Factor Receptor Improves Myelination and Attenuates Tissue Damage of Spinal Cord Injury.

    Science.gov (United States)

    Zhang, Si; Ju, Peijun; Tjandra, Editha; Yeap, Yeeshan; Owlanj, Hamed; Feng, Zhiwei

    2016-10-01

    Preventing demyelination and promoting remyelination of denuded axons are promising therapeutic strategies for spinal cord injury (SCI). Epidermal growth factor receptor (EGFR) inhibition was reported to benefit the neural functional recovery and the axon regeneration after SCI. However, its role in de- and remyelination of axons in injured spinal cord is unclear. In the present study, we evaluated the effects of EGFR inhibitor, PD168393 (PD), on the myelination in mouse contusive SCI model. We found that expression of myelin basic protein (MBP) in the injured spinal cords of PD treated mice was remarkably elevated. The density of glial precursor cells and oligodendrocytes (OLs) was increased and the cell apoptosis in lesions was attenuated after PD168393 treatment. Moreover, PD168393 treatment reduced both the numbers of OX42 + microglial cells and glial fibrillary acidic protein + astrocytes in damaged area of spinal cords. We thus conclude that the therapeutic effects of EGFR inhibition after SCI involves facilitating remyelination of the injured spinal cord, increasing of oligodendrocyte precursor cells and OLs, as well as suppressing the activation of astrocytes and microglia/macrophages. PMID:26883518

  20. Radiation damage simulation studies of selected austenitic and ferritic alloys

    International Nuclear Information System (INIS)

    Results are presented of a study of the radiation damage structure of selected alloys following ion bombardment to simulate fusion-reactor exposures up to 40 dpa (approx. 3 MW-yr m-2) at temperatures from 4750C-6500C. Gas concentrations appropriate to fusion-reactor conditions were simulated using a mixed gas beam of 4 MeV He + 2 MeV H2. A beam of 46 MeV Ni ions was used in sequence with the gas beam to provide gas-to-damage ratios of 13 appm He/dpa and 52 appm H/dpa at a nickel-ion damage rate of approx. 1 dpa/hr. The materials investigated comprised three austenitic stainless steels (316L, modified 316-Ti and 316-Nb), a ferritic alloy (1.4914) and a commercial low-activation alloy containing Mn (TENELON). The results reveal that ferritic steels have good radiation damage resistance and are far superior to austenitic steels in respect of void-induced swelling. (author)

  1. Study on radiation damage of electron and γ-rays and mechanism of nuclear hardening

    International Nuclear Information System (INIS)

    Radiation damage effects of electrons and γ-rays are presented. The damage defects are studied by experimental methods. On the basis of these studies the damage mechanism and nuclear hardening techniques are studied

  2. Measurement of radiation damage of water-based liquid scintillator and liquid scintillator

    International Nuclear Information System (INIS)

    Liquid scintillating phantoms have been proposed as a means to perform real-time 3D dosimetry for proton therapy treatment plan verification. We have studied what effect radiation damage to the scintillator will have upon this application. We have performed measurements of the degradation of the light yield and optical attenuation length of liquid scintillator and water-based liquid scintillator after irradiation by 201 MeV proton beams that deposited doses of approximately 52 Gy, 300 Gy, and 800 Gy in the scintillator. Liquid scintillator and water-based liquid scintillator (composed of 5% scintillating phase) exhibit light yield reductions of 1.74 ± 0.55 % and 1.31 ± 0.59 % after 0≈ 80 Gy of proton dose, respectively. Whilst some increased optical attenuation was observed in the irradiated samples, the measured reduction to the light yield is also due to damage to the scintillation light production. Based on our results and conservative estimates of the expected dose in a clinical context, a scintillating phantom used for proton therapy treatment plan verification would exhibit a systematic light yield reduction of approximately 0.1% after a year of operation

  3. Measurement of Radiation Damage of Water-based Liquid Scintillator and Liquid Scintillator

    CERN Document Server

    Bignell, Lindsey J; Hans, Sunej; Jaffe, David E; Rosero, Richard; Vigdor, Steven; Viren, Brett; Worcester, Elizabeth; Yeh, Minfang; Zhang, Chao

    2015-01-01

    Liquid scintillating phantoms have been proposed as a means to perform real-time 3D dosimetry for proton therapy treatment plan verification. We have studied what effect radiation damage to the scintillator will have upon this application. We have performed measurements of the degradation of the light yield and optical attenuation length of liquid scintillator and water-based liquid scintillator after irradiation by 201 MeV proton beams that deposited doses of approximately 52 Gy, 300 Gy, and 800 Gy in the scintillator. Liquid scintillator and water-based liquid scintillator (composed of $5\\%$ scintillating phase) exhibit light yield reductions of $1.74 \\pm 0.55 \\%$ and $1.31 \\pm 0.59 \\%$ after $\\approx$ 800 Gy of proton dose, respectively. Whilst some increased optical attenuation was observed in the irradiated samples, the measured reduction to the light yield is also due to damage to the scintillation light production. Based on our results and conservative estimates of the expected dose in a clinical conte...

  4. Investigation of damage mechanism by ionising radiation on biomolecules

    International Nuclear Information System (INIS)

    Occupational radiation hazard is a very controversial subject. Effects from high radiation doses are well known from past experiences. However, hazard from low doses is still a subject that is hotly debated upon until now. The occupational dosimetry used now is based on a macroscopic scale. Lately, microdosimetry is fast gaining recognition as a more superior way of measuring hazard. More importantly, scientists are researching the basic damage mechanism that leads to biological effects by ionising radiation. In this report, a simulation study of the basic damage mechanism is discussed . This simulation is based upon Monte Carlo calculations and using polyuridylic acid (Poly-U) as the DNA model This simulation tries to relate the physics and chemistry of interactions of ionising radiation with biomolecules. The computer codes used in this simulation, OREC and RADLYS were created by Hamm et al. (1983) in Oak Ridge National Laboratory. The biological endpoints in this simulation are the strand break and base release of the DNA, which is the precursor of all biological effects. These results are compared with model studies that had been done experimentally to check the validity of this simulation. The G-values of strand break and base release from this simulation were -2.35 and 2.75 and compared well with results from irradiation experiments by von Sonntag (I 98 7) from Max Plank's Institute, Germany

  5. Sirtuin 7 promotes cellular survival following genomic stress by attenuation of DNA damage, SAPK activation and p53 response

    International Nuclear Information System (INIS)

    Maintaining the genomic integrity is a constant challenge in proliferating cells. Amongst various proteins involved in this process, Sirtuins play a key role in DNA damage repair mechanisms in yeast as well as mammals. In the present work we report the role of one of the least explored Sirtuin viz., SIRT7, under conditions of genomic stress when treated with doxorubicin. Knockdown of SIRT7 sensitized osteosarcoma (U2OS) cells to DNA damage induced cell death by doxorubicin. SIRT7 overexpression in NIH3T3 delayed cell cycle progression by causing delay in G1 to S transition. SIRT7 overexpressing cells when treated with low dose of doxorubicin (0.25 µM) showed delayed onset of senescence, lesser accumulation of DNA damage marker γH2AX and lowered levels of growth arrest markers viz., p53 and p21 when compared to doxorubicin treated control GFP expressing cells. Resistance to DNA damage following SIRT7 overexpression was also evident by EdU incorporation studies where cellular growth arrest was significantly delayed. When treated with higher dose of doxorubicin (>1 µM), SIRT7 conferred resistance to apoptosis by attenuating stress activated kinases (SAPK viz., p38 and JNK) and p53 response thereby shifting the cellular fate towards senescence. Interestingly, relocalization of SIRT7 from nucleolus to nucleoplasm together with its co-localization with SAPK was an important feature associated with DNA damage. SIRT7 mediated resistance to doxorubicin induced apoptosis and senescence was lost when p53 level was restored by nutlin treatment. Overall, we propose SIRT7 attenuates DNA damage, SAPK activation and p53 response thereby promoting cellular survival under conditions of genomic stress. - Highlights: • Knockdown of SIRT7 sensitized cells to DNA damage induced apoptosis. • SIRT7 delayed onset of premature senescence by attenuating DNA damage response. • Overexpression of SIRT7 delayed cell cycle progression by delaying G1/S transition. • Upon DNA damage SIRT

  6. Sirtuin 7 promotes cellular survival following genomic stress by attenuation of DNA damage, SAPK activation and p53 response

    Energy Technology Data Exchange (ETDEWEB)

    Kiran, Shashi; Oddi, Vineesha [Laboratory of Cancer Biology, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, 500001 (India); Ramakrishna, Gayatri, E-mail: gayatrirama1@gmail.com [Laboratory of Cancer Biology, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, 500001 (India); Laboratory of Cancer Cell Biology, Department of Research, Institute of Liver and Biliary Sciences, Delhi 110070 (India)

    2015-02-01

    Maintaining the genomic integrity is a constant challenge in proliferating cells. Amongst various proteins involved in this process, Sirtuins play a key role in DNA damage repair mechanisms in yeast as well as mammals. In the present work we report the role of one of the least explored Sirtuin viz., SIRT7, under conditions of genomic stress when treated with doxorubicin. Knockdown of SIRT7 sensitized osteosarcoma (U2OS) cells to DNA damage induced cell death by doxorubicin. SIRT7 overexpression in NIH3T3 delayed cell cycle progression by causing delay in G1 to S transition. SIRT7 overexpressing cells when treated with low dose of doxorubicin (0.25 µM) showed delayed onset of senescence, lesser accumulation of DNA damage marker γH2AX and lowered levels of growth arrest markers viz., p53 and p21 when compared to doxorubicin treated control GFP expressing cells. Resistance to DNA damage following SIRT7 overexpression was also evident by EdU incorporation studies where cellular growth arrest was significantly delayed. When treated with higher dose of doxorubicin (>1 µM), SIRT7 conferred resistance to apoptosis by attenuating stress activated kinases (SAPK viz., p38 and JNK) and p53 response thereby shifting the cellular fate towards senescence. Interestingly, relocalization of SIRT7 from nucleolus to nucleoplasm together with its co-localization with SAPK was an important feature associated with DNA damage. SIRT7 mediated resistance to doxorubicin induced apoptosis and senescence was lost when p53 level was restored by nutlin treatment. Overall, we propose SIRT7 attenuates DNA damage, SAPK activation and p53 response thereby promoting cellular survival under conditions of genomic stress. - Highlights: • Knockdown of SIRT7 sensitized cells to DNA damage induced apoptosis. • SIRT7 delayed onset of premature senescence by attenuating DNA damage response. • Overexpression of SIRT7 delayed cell cycle progression by delaying G1/S transition. • Upon DNA damage SIRT

  7. PREFACE: Radiation Damage in Biomolecular Systems (RADAM07)

    Science.gov (United States)

    McGuigan, Kevin G.

    2008-03-01

    The annual meeting of the COST P9 Action `Radiation damage in biomolecular systems' took place from 19-22 June 2007 in the Royal College of Surgeons in Ireland, in Dublin. The conference was structured into 5 Working Group sessions: Electrons and biomolecular interactions Ions and biomolecular interactions Radiation in physiological environments Theoretical developments for radiation damage Track structure in cells Each of the five working groups presented two sessions of invited talks. Professor Ron Chesser of Texas Tech University, USA gave a riveting plenary talk on `Mechanisms of Adaptive Radiation Responses in Mammals at Chernobyl' and the implications his work has on the Linear-No Threshold model of radiation damage. In addition, this was the first RADAM meeting to take place after the Alexander Litvenenko affair and we were fortunate to have one of the leading scientists involved in the European response Professor Herwig Paretzke of GSF-Institut für Strahlenschutz, Neuherberg, Germany, available to speak. The remaining contributions were presented in the poster session. A total of 72 scientific contributions (32 oral, 40 poster), presented by 97 participants from 22 different countries, gave an overview on the current progress in the 5 different subfields. A 1-day pre-conference `Early Researcher Tutorial Workshop' on the same topic kicked off on 19 June attended by more than 40 postgrads, postdocs and senior researchers. Twenty papers, based on these reports, are included in this volume of Journal of Physics: Conference Series. All the contributions in this volume were fully refereed, and they represent a sample of the courses, invited talks and contributed talks presented during RADAM07. The interdisciplinary RADAM07 conference brought together researchers from a variety of different fields with a common interest in biomolecular radiation damage. This is reflected by the disparate backgrounds of the authors of the papers presented in these proceedings

  8. Radiation Damage Effect on Si and SiC Detectors

    International Nuclear Information System (INIS)

    Silicon is an extraordinary semiconductor suited for the fabrication of radiation detector. Charge carrier lifetime and mobility are high, which is very important to make the radiation detector with low noise and good time behavior. Since the fabrication technology of the silicon was mature, one could easily make a radiation detector with a sophisticated structure. Therefore, silicon detector could be the best choice for the various application areas. The depletion layers of the reverse bias rectifying barriers are used to make the silicon radiation detector with low noise. The depletion layer could be made by a silicon surface barrier (SSB) structure or a PIN junction structure. SSB detector was made by depositing the metal electrode on the n or p type silicon wafer. The p-n junction could be made with the semiconductor fabrication process, and the X-ray or α particles could be measured with the detector. The radiation tolerance of the radiation detector is also very important for the application of the detector to the harsh environment. A study on the effect of the structure of the depletion layer on the radiation tolerance was rare in most of the previous works In the present work, the silicon detectors with two types were fabricated, and their operation characteristics are compared. The dependency of the radiation damage on the detector type was studied. We also fabricated SiC detector and the neutron and gamma irradiation effect on the detector was studied. The radiation tolerance of the detector was studied. One could see the change of the leakage current and the energy resolution in SSB detector, and the operating performance of the Si PIN detector was more stable than Si Schottky detector.

  9. Attenuation of X and Gamma Rays in Personal Radiation Shielding Protective Clothing.

    Science.gov (United States)

    Kozlovska, Michaela; Cerny, Radek; Otahal, Petr

    2015-11-01

    A collection of personal radiation shielding protective clothing, suitable for use in case of accidents in nuclear facilities or radiological emergency situations involving radioactive agents, was gathered and tested at the Nuclear Protection Department of the National Institute for Nuclear, Chemical and Biological Protection, Czech Republic. Attenuating qualities of shielding layers in individual protective clothing were tested via spectra measurement of x and gamma rays, penetrating them. The rays originated from different radionuclide point sources, the gamma ray energies of which cover a broad energy range. The spectra were measured by handheld spectrometers, both scintillation and High Purity Germanium. Different narrow beam geometries were adjusted using a special testing bench and a set of various collimators. The main experimentally determined quantity for individual samples of personal radiation shielding protective clothing was x and gamma rays attenuation for significant energies of the spectra. The attenuation was assessed comparing net peak areas (after background subtraction) in spectra, where a tested sample was placed between the source and the detector, and corresponding net peak areas in spectra, measured without the sample. Mass attenuation coefficients, which describe attenuating qualities of shielding layers materials in individual samples, together with corresponding lead equivalents, were determined as well. Experimentally assessed mass attenuation coefficients of the samples were compared to the referred ones for individual heavy metals. PMID:26425983

  10. Delayed damage after radiation therapy for head and neck cancer

    International Nuclear Information System (INIS)

    I investigated radiation damage, including osteoradionecrosis, arising from tooth extraction in fields that had received radiation therapy for head and neck cancer, and evaluated the effectiveness of pilocarpine for xerostomia. Between January 1990 and April 1996, I examined 30 patients for bone changes after tooth extraction in fields irradiated at the Department of Oral Radiology, Osaka Dental University Hospital. Nineteen of the patients had been treated for nasopharyngeal cancer and 11 for oropharyngeal cancer. Between January and April 1996, 4 additional patients were given pilocarpine hydrochloride (3-mg, 6-mg and 9-mg of KSS-694 orally three times a day) for 12 weeks and evaluated every 4 weeks as a base line. One had been treated for nasopharyngeal carcinoma, two for cancer of the cheek and one for an unknown carcinoma. Eighteen of the patients (11 with nasopharyngeal carcinoma and 7 with oropharyngeal carcinoma) had extractions. Use of preoperative and postoperative radiographs indicated that damage to the bone following tooth extraction after radiation exposure was related to whether antibiotics were administered the day before the extraction, whether forceps or elevators were used, and whether the tooth was in the field of radiation. Xerostomia improved in all 4 of the patients who received 6-mg or 9-mg of pilocarpine. It improved saliva production and relieved the symptoms of xerostomia after radiation therapy for head and neck cancer, although there were minor side effects such as fever. This information can be used to improve the oral environment of patients who have received radiation therapy for head and neck cancer, and to better understand their oral environment. (author)

  11. Defense mechanisms against radiation induced teratogenic damage in mice

    International Nuclear Information System (INIS)

    Experimental studies with mice have established that fetuses at midgestational stage are highly susceptible to malformation at high, but not low, doses of radiation. When DNA damage is produced by a small amount of radiation, it is efficiently eliminated by DNA repair. However, DNA repair is not perfect. There must be defense mechanisms other than DNA repair. In order to elucidate the essential role of p53 gene in apoptotic tissue repair, we compared the incidence of radiation-induced malformations and deaths (deaths after day 10) in wild-type p53 (+/+) mice and null p53 (-/-) mice. For p53 (+/+) mice, an X-ray dose of 2 Gy given at a high dose-rate (450 mGy/min) to fetuses at 9.5 days of gestation was highly lethal and considerably teratogenic whereas it was only slightly lethal but highly teratogenic for p53 (-/-) fetuses. This reciprocal relationship of radiosensitivity to malformations and deaths supports the notion that fetal tissues have a p53 -dependent idguardianln of the tissue that aborts cells bearing radiation-induced teratogenic DNA damage. When an equal dose of 2 Gy given at a 400-fold lower dose-rate (1.2 mGy/min), this dose became not teratogenic for p53 (+/+) fetuses exhibiting p53 -dependent apoptosis, whereas this dose remained teratogenic for p53 (-/-) fetuses unable to carry out apoptosis. Furthermore, when the dose was divided into two equal dose fractions (1+1 Gy) at high dose rate, separated by 24 hours, the incidences of malformations were equal with control level for p53 (+/+), but higher for p53 (-/-) mice. Hence, complete elimination of teratogenic damage from irradiated tissues requires a concerted cooperation of two mechanisms; proficient DNA repair and p53-dependent apoptotic tissue repair

  12. Radiation Background and Attenuation Model Validation and Development

    Energy Technology Data Exchange (ETDEWEB)

    Peplow, Douglas E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Santiago, Claudio P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-08-05

    This report describes the initial results of a study being conducted as part of the Urban Search Planning Tool project. The study is comparing the Urban Scene Simulator (USS), a one-dimensional (1D) radiation transport model developed at LLNL, with the three-dimensional (3D) radiation transport model from ORNL using the MCNP, SCALE/ORIGEN and SCALE/MAVRIC simulation codes. In this study, we have analyzed the differences between the two approaches at every step, from source term representation, to estimating flux and detector count rates at a fixed distance from a simple surface (slab), and at points throughout more complex 3D scenes.

  13. Snowpack snow water equivalent measurement using the attenuation of cosmic gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Osterhuber, R. [Univ. of California, Soda Springs, CA (United States). Central Sierra Snow Lab.; Fehrke, F. [California Dept. of Water Resources, Sacramento, CA (United States); Condreva, K. [Sandia National Labs., Livermore, CA (United States)

    1998-05-01

    Incoming, background cosmic radiation constantly fluxes through the earth`s atmosphere. The high energy gamma portion of this radiation penetrates many terrestrial objects, including the winter snowpack. The attenuation of this radiation is exponentially related to the mass of the medium through which it penetrates. For the past three winters, a device measuring cosmic gamma radiation--and its attenuation through snow--has been installed at the Central Sierra Snow Laboratory, near Donner Pass, California. This gamma sensor, measuring energy levels between 5 and 15 MeV, has proved to be an accurate, reliable, non-invasive, non-mechanical instrument with which to measure the total snow water equivalent of a snowpack. This paper analyzes three winters` worth of data and discusses the physics and practical application of the sensor for the collection of snow water equivalent data from a remote location.

  14. Snowpack snow water equivalent measurement using the attenuation of cosmic gamma radiation

    International Nuclear Information System (INIS)

    Incoming, background cosmic radiation constantly fluxes through the earth's atmosphere. The high energy gamma portion of this radiation penetrates many terrestrial objects, including the winter snowpack. The attenuation of this radiation is exponentially related to the mass of the medium through which it penetrates. For the past three winters, a device measuring cosmic gamma radiation--and its attenuation through snow--has been installed at the Central Sierra Snow Laboratory, near Donner Pass, California. This gamma sensor, measuring energy levels between 5 and 15 MeV, has proved to be an accurate, reliable, non-invasive, non-mechanical instrument with which to measure the total snow water equivalent of a snowpack. This paper analyzes three winters' worth of data and discusses the physics and practical application of the sensor for the collection of snow water equivalent data from a remote location

  15. Radiation damage of the HEAO C-1 germanium detectors

    Science.gov (United States)

    Mahoney, W. A.; Ling, J. C.; Jacobson, A. S.

    1981-01-01

    The effects of radiation damage from proton bombardment of the four HEAO C-1 high purity germanium detectors have been measured and compared to predictions. Because of the presence of numerous gamma-ray lines in the detector background spectra and because of the relatively long exposure time of the HEAO 3 satellite to cosmic-ray and trapped protons, it has been possible to measure both the energy and time dependence of radiation damage. After 100 d in orbit, each of the four detectors has been exposed to approximately 3 x 10 to the 7th protons/sq cm, and the average energy resolution at 1460 keV had degraded from 3.2 keV fwhm to 8.6 keV fwhm. The lines were all broadened to the low energy side although the line profile was different for each of the four detectors. The damage-related contribution to the degradation in energy resolution was found to be linear in energy and proton influence.

  16. Protective Effect of HSP25 on Radiation Induced Tissue Damage

    International Nuclear Information System (INIS)

    Control of cancer by irradiation therapy alone or in conjunction with combination chemotherapy is often limited by organ specific toxicity. Ionizing irradiation toxicity is initiated by damage to normal tissue near the tumor target and within the transit volume of radiotherapy beams. Irradiation-induced cellular, tissue, and organ damage is mediated by acute effects, which can be dose limiting. A latent period follows recovery from the acute reaction, then chronic irradiation fibrosis (late effects) pose a second cause of organ failure. HSP25/27 has been suggested to protect cells against apoptotic cell death triggered by hyperthermia, ionizing radiation, oxidative stress, Fas ligand, and cytotoxic drugs. And several mechanisms have been proposed to account for HSP27-mediated apoptotic protection. However radioprotective effect of HSP25/27 in vivo system has not yet been evaluated. The aim of this study was to evaluate the potential of exogenous HSP25 expression, as delivered by adenoviral vectors, to protect animal from radiation induced tissue damage

  17. Influence of radiation damage on xenon diffusion in silicon carbide

    Science.gov (United States)

    Friedland, E.; Gärtner, K.; Hlatshwayo, T. T.; van der Berg, N. G.; Thabethe, T. T.

    2014-08-01

    Diffusion of xenon in poly and single crystalline silicon carbide and the possible influence of radiation damage on it are investigated. For this purpose 360 keV xenon ions were implanted in commercial 6H-SiC and CVD-SiC wafers at room temperature, 350 °C and 600 °C. Width broadening of the implantation profiles and xenon retention during isochronal and isothermal annealing up to temperatures of 1500 °C was determined by RBS-analysis, whilst in the case of 6H-SiC damage profiles were simultaneously obtained by α-particle channelling. No diffusion or xenon loss was detected in the initially amorphized and eventually recrystallized surface layer of cold implanted 6H-SiC during annealing up to 1200 °C. Above that temperature serious erosion of the implanted surface occurred, which made any analysis impossible. No diffusion or xenon loss is detected in the hot implanted 6H-SiC samples during annealing up to 1400 °C. Radiation damage dependent grain boundary diffusion is observed at 1300 °C in CVD-SiC.

  18. Repair of DNA damage induced by ultraviolet radiation

    International Nuclear Information System (INIS)

    Studies documenting the depletion of the ozone layer and the resulting increases in UV-B radiation (280-320 nm) at the Earth's surface have served to focus attention on the biological effects of UV light. One obvious target for UVB- induced damage is DNA. Although a11 biological tissues are rich in UV-absorbing agents (largely nucleic acids and proteins) and plants produce additional UV-absorbing pigments, no DNA in superficial tissue can completely avoid UV exposure. Plants, like a11 living organisms, must have some capacity for the repair of UV-induced DNA damage. Because plants are unique in the obligatory nature of their exposure to UV, it is also conceivable that they may have evolved particularly efficient mechanisms for the elimination of UV-induced DNA damage. This review will summarize what we know about DNA repair mechanisms in higher plants. Readers interested in broader aspects of UV-induced damage and UV filters are directed to recent reviews (Middleton and Teramura, 1994; Strid et al., 1994; Fiscus and Booker, 1995). Our knowledge of DNA repair mechanisms in plants lags far behind our understanding of these pathways in animals, and a significant number of questions concerning the basic phenomenology of DNA repair in plants remain to be addressed

  19. Radiation Damages in Aluminum Alloy SAV-1 under Neutron Irradiation

    Science.gov (United States)

    Salikhbaev, Umar; Akhmedzhanov, Farkhad; Alikulov, Sherali; Baytelesov, Sapar; Boltabaev, Azizbek

    2016-05-01

    The aim of this work was to study the effect of neutron irradiation on the kinetics of radiation damages in the SAV-1 alloy, which belongs to the group of aluminum alloys of the ternary system Al-Mg-Si. For fast-neutron irradiation by different doses up to fluence 1019 cm-2 the SAV-1 samples were placed in one of the vertical channels of the research WWR type reactor (Tashkent). The temperature dependence of the electrical resistance of the alloy samples was investigated in the range 290 - 490 K by the four-compensation method with an error about 0.1%. The experimental results were shown that at all the temperatures the dependence of the SAV-1 alloy resistivity on neutron fluence was nonlinear. With increasing neutron fluence the deviation from linearity and the growth rate of resistivity with temperature becomes more appreciable. The observed dependences are explained by means of martensitic transformations and the radiation damages in the studied alloy under neutron irradiation. The mechanisms of radiation modification of the SAV-1 alloy structure are discussed.

  20. A radiation damage repair model for normal tissues

    Energy Technology Data Exchange (ETDEWEB)

    Partridge, Mike [Institute of Cancer Research, Downs Road, Sutton, SM2 5PT (United Kingdom)

    2008-07-07

    A cellular Monte Carlo model describing radiation damage and repair in normal epithelial tissues is presented. The deliberately simplified model includes cell cycling, cell motility and radiation damage response (cell cycle arrest and cell death) only. Results demonstrate that the model produces a stable equilibrium system for mean cell cycle times in the range 24-96 h. Simulated irradiation of these stable equilibrium systems produced a range of responses that are shown to be consistent with experimental and clinical observation, including (i) re-epithelialization of radiation-induced lesions by a mixture of cell migration into the wound and repopulation at the periphery; (ii) observed radiosensitivity that is quantitatively consistent with both rate of induction of irreparable DNA lesions and, independently, with the observed acute oral and pharyngeal mucosal reactions to radiotherapy; (iii) an observed time between irradiation and maximum toxicity that is consistent with experimental data for skin; (iv) quantitatively accurate predictions of low-dose hyper-radiosensitivity; (v) Gomperzian repopulation for very small lesions ({approx}2000 cells) and (vi) a linear rate of re-epithelialization of 5-10 {mu}m h{sup -1} for large lesions (>15 000 cells)

  1. A radiation damage repair model for normal tissues

    Science.gov (United States)

    Partridge, Mike

    2008-07-01

    A cellular Monte Carlo model describing radiation damage and repair in normal epithelial tissues is presented. The deliberately simplified model includes cell cycling, cell motility and radiation damage response (cell cycle arrest and cell death) only. Results demonstrate that the model produces a stable equilibrium system for mean cell cycle times in the range 24-96 h. Simulated irradiation of these stable equilibrium systems produced a range of responses that are shown to be consistent with experimental and clinical observation, including (i) re-epithelialization of radiation-induced lesions by a mixture of cell migration into the wound and repopulation at the periphery; (ii) observed radiosensitivity that is quantitatively consistent with both rate of induction of irreparable DNA lesions and, independently, with the observed acute oral and pharyngeal mucosal reactions to radiotherapy; (iii) an observed time between irradiation and maximum toxicity that is consistent with experimental data for skin; (iv) quantitatively accurate predictions of low-dose hyper-radiosensitivity; (v) Gomperzian repopulation for very small lesions (~2000 cells) and (vi) a linear rate of re-epithelialization of 5-10 µm h-1 for large lesions (>15 000 cells).

  2. The evaluation of radiation damage parameter for CVD diamond

    Science.gov (United States)

    Grilj, V.; Skukan, N.; Jakšić, M.; Pomorski, M.; Kada, W.; Kamiya, T.; Ohshima, T.

    2016-04-01

    There are a few different phenomenological approaches that aim to track the dependence of signal height in irradiated solid state detectors on the fluence of damaging particles. However, none of them are capable to provide a unique radiation hardness parameter that would reflect solely the material capability to withstand high radiation environment. To extract such a parameter for chemical vapor deposited (CVD) diamond, two different diamond detectors were irradiated with proton beams in MeV energy range and subjected afterwards to ion beam induced charge (IBIC) analysis. The change in charge collection efficiency (CCE) due to defects produced was investigated in context of a theoretical model that was developed on the basis of the adjoint method for linearization of the continuity equations of electrons and holes. Detailed modeling of measured data resulted with the first known value of the kσ product for diamond, where k represents the number of charge carriers' traps created per one simulated primary lattice vacancy and σ represents the charge carriers' capture cross section. As discussed in the text, this product could be considered as a true radiation damage parameter.

  3. Radiation-damage study of a monocrystalline tungsten positron converter

    CERN Document Server

    Artru, X; Chehab, R; Johnson, B; Keppler, P; Major, J V; Rinolfi, Louis; Jejcic, A

    1998-01-01

    The exploitation of the enhancement of positron sources by channeling effects, in particular for Linear Colliders (LC), relies on the long term resistance of the crystal to radiation damage. Such dama ge has been tested on a 0.3 mm thick tungsten monocrystal exposed during 6 months to the 30 Gev incident electron beam of the SLAC Linear Collider (SLC). The crystal was placed in the converter region , orientated in a random direction and received an integrated flux of e- (fluence) of 2 x 10^18 e-/mm^2. The crystal was analyzed before and after irradiation by X and Gamma diffractometry. No damage was observed, the mosaic spread remained unchanged during irradiation (0.4 mrad FWHM). Implications for use of orientated crystal as converter for positron sources of future LCs are discussed.

  4. A Mathematical Model for Estimating Biological Damage Caused by Radiation

    CERN Document Server

    Manabe, Yuichiro; Bando, Masako

    2012-01-01

    We propose a mathematical model for estimating biological damage caused by low-dose irradiation. We understand that the Linear Non Threshold (LNT) hypothesis is realized only in the case of no recovery effects. In order to treat the realistic living objects, our model takes into account various types of recovery as well as proliferation mechanism, which may change the resultant damage, especially for the case of lower dose rate irradiation. It turns out that the lower the radiation dose rate, the safer the irradiated system of living object (which is called symbolically "tissue" hereafter) can have chances to survive, which can reproduce the so-called dose and dose-rate effectiveness factor (DDREF).

  5. A Mathematical Model for Estimating Biological Damage Caused by Radiation

    Science.gov (United States)

    Manabe, Yuichiro; Ichikawa, Kento; Bando, Masako

    2012-10-01

    We propose a mathematical model for estimating biological damage caused by low-dose irradiation. We understand that the linear non threshold (LNT) hypothesis is realized only in the case of no recovery effects. In order to treat the realistic living objects, our model takes into account various types of recovery as well as proliferation mechanism, which may change the resultant damage, especially for the case of lower dose rate irradiation. It turns out that the lower the radiation dose rate, the safer the irradiated system of living object (which is called symbolically ``tissue'' hereafter) can have chances to survive, which can reproduce the so-called dose and dose-rate effectiveness factor (DDREF).

  6. Radiation damage and activation evaluations for the ELSY reactor

    International Nuclear Information System (INIS)

    The paper presents the main results of the preliminary evaluations regarding the radiation damage on the structural materials of the ELSY reactor (European Lead cooled SYstem) performed during the design stage of the plant (1500 MWth). The standard damage parameter for the nuclear materials is DPA (displacements per atom) which incorporates information about the response of the material, as well as the value of the neutron fluence at which the material is exposed. The second aim of the present work consists in the estimation of the lead coolant activation. The evaluations are performed at various irradiation and cooling time steps; the inventories carried out could be used in further analyses regarding the radioprotection, waste characterization and disposal, etc. (authors)

  7. Interleukin 17A evoked mucosal damage is attenuated by cannabidiol and anandamide in a human colonic explant model.

    Science.gov (United States)

    Harvey, B S; Sia, T C; Wattchow, D A; Smid, S D

    2014-02-01

    Interleukin 17A (IL-17A) is a cytokine linked to inflammatory bowel disease. We investigated IL-17A expression in human colonic mucosa, whether IL-17A can elicit colonic mucosal damage in a human explant model and modulate gastrointestinal epithelial permeability in cell culture. We also tested if select cannabinoid ligands, shown to be protective in colitis models could attenuate damage caused by IL-17A. In addition, the ability of pro-inflammatory cytokines TNF-α and IL-1β to modulate levels of IL-17A in the explant colitis model was also explored. IL-17A incubation caused significant mucosal epithelial and crypt damage which were attenuated following hydrocortisone treatment, and also reduced following anandamide or cannabidiol incubation. IL-17A-evoked mucosal damage was also associated with an increase in matrix metalloprotease activity. However, IL-17A did not induce any significant changes in epithelial permeability in confluent Caco-2 cell monolayers over a 48h incubation period. IL-17A was located predominantly in human mucosal epithelium together with IL-17C, but both IL-17A and IL-17C were also expressed in the lamina propria and submucosa. Incubation of human colonic mucosal tissue or Caco-2 cells with pro-inflammatory cytokines TNF-α and IL-1β however did not alter IL-17A expression. These results indicate IL-17A has a widespread distribution in the human colon and the capacity to elicit mucosal damage which can be attenuated by cannabinoid ligands. PMID:24238999

  8. Relationship between the repair of radiation-induced DNA damage and recovery from potentially lethal damage in 9L rat brain tumor cells. [Gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    vanAnkeren, S.C.; Wheeler, K.T.

    1984-03-01

    The kinetics of repair of radiation-induced DNA damage and recovery from radiation-induced potentially lethal damage (PLD) for fed plateau-phase 9L/Ro rat brain tumor cells were compared after single doses of gamma-radiation and after combined treatment with 3 micrograms of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU)/ml given 16 hr prior to irradiation. DNA damage and repair were assayed using alkaline filter elution, while cell survival was assayed by colony formation. Repair of radiation-induced DNA damage and recovery from radiation-induced PLD followed statistically identical biphasic kinetics; the fast-phase half-times were 4.1 +/- 0.3 (S.D.) min and 4.0 +/- 0.8 min, while the slow-phase half-times were 59.7 +/- 11.2 min and 78.7 +/- 34.1 min, respectively. Treatment with BCNU prior to irradiation resulted in both additional DNA damage and increased cell kill. When DNA damage and cell survival after the combined treatment were corrected for the contribution from BCNU given alone, no inhibition of either repair of radiation-induced DNA damage or of recovery from radiation-induced PLD was observed. However, postirradiation hypertonic treatment inhibited both DNA repair and recovery from radiation-induced PLD. These correlations between the kinetics of the molecular and cellular repair processes support a role for repair of radiation-induced DNA damage in recovery from radiation-induced PLD. The lack of inhibition by BCNU of both repair of radiation-induced DNA damage and of recovery from radiation-induced PLD also demonstrates that these are not the mechanisms by which BCNU enhances radiation-induced cytotoxicity in 9L cells.

  9. Radiation damage monitoring of the ATLAS pixel detector

    CERN Document Server

    Seidel, Sally; The ATLAS collaboration

    2015-01-01

    A measurement has been made of the radiation damage incurred by the ATLAS Pixel Detector barrel silicon modules from the beginning of operations through the end of 2012. This translates to hadronic fluence received over the full period of operation at energies up to and including 8 TeV. The measurement is based on a per-module record of the silicon sensor leakage current. The results are presented as a function of integrated luminosity and compared to predictions by the Hamburg Model. This information can be used to predict limits on the lifetime of the Pixel Detector due to current, for various operating scenarios.

  10. A new mechanism for radiation damage processes in alkali halides

    OpenAIRE

    Dubinko, V. I.; Turkin, A.A.; Vainshtein, D.I.; Hartog, H.W. den

    1999-01-01

    We present a theory of radiation damage formation in alkali halides based on a new mechanism of dislocation climb, which involves the production of VF centers (self-trapped hole neighboring a cation vacancy) as a result of the absorption of H centers of dislocation lines. We consider the evolution of all experimentally observed extended defects: metal colloids, gas bubbles, and vacancy voids. Voids are shown to arise and grow large due to the reaction between F and VF centers at the surface o...

  11. A new mechanism for radiation damage processes in alkali halides

    Science.gov (United States)

    Dubinko, V. I.; Turkin, A. A.; Vainshtein, D. I.; den Hartog, H. W.

    1999-12-01

    We present a theory of radiation damage formation in alkali halides based on a new mechanism of dislocation climb, which involves the production of VF centers (self-trapped hole neighboring a cation vacancy) as a result of the absorption of H centers of dislocation lines. We consider the evolution of all experimentally observed extended defects: metal colloids, gas bubbles, and vacancy voids. Voids are shown to arise and grow large due to the reaction between F and VF centers at the surface of halogen bubbles. Voids can ignite a back reaction between the radiolytic products resulting in decomposition of the irradiated material.

  12. Radiation damage and annealing of amorphous silicon solar cells

    Science.gov (United States)

    Byvik, C. E.; Slemp, W. S.; Smith, B. T.; Buoncristiani, A. M.

    1984-01-01

    Amorphous silicon solar cells were irradiated with 1 MeV electrons at the Space Environmental Effects Laboratory of the NASA Langley Research Center. The cells accumulated a total fluence of 10 to the 14th, 10 to the 15th, and 10 to the 16th electrons per square centimeter and exhibited increasing degradation with each irradiation. This degradation was tracked by evaluating the I-V curves for AM0 illumination and the relative spectral response. The observed radiation damage was reversed following an anneal of the cells under vacuum at 200 C for 2 hours.

  13. Compilation of radiation damage test data cable insulating materials

    CERN Document Server

    Schönbacher, H; CERN. Geneva

    1979-01-01

    This report summarizes radiation damage test data on commercially available organic cable insulation and jacket materials: ethylene- propylene rubber, Hypalon, neoprene rubber, polyethylene, polyurethane, polyvinylchloride, silicone rubber, etc. The materials have been irradiated in a nuclear reactor to integrated absorbed doses from 5*10/sup 5/ to 5*10/sup 6/ Gy. Mechanical properties, e.g. tensile strength, elongation at break, and hardness, have been tested on irradiated and non-irradiated samples. The results are presented in the form of tables and graphs, to show the effect of the absorbed dose on the measured properties. (13 refs).

  14. Hemotopoetic radiation damage in mice with the leukemia virus

    International Nuclear Information System (INIS)

    Effect of congenital carriage of tumorgenic viruses on the radioresistance of mice exposed to ionizing radiation is studied. Mice were irradiated by γ-rays of 137Cs source at 0.5-8.0 Gy doses and 1.5 Gy/min dose rate. It is shown that mice-carriers of virus (T-leukosis) are more radiosensitive according to survival rate and hemopoiesis state. It is supposed that the decrease in leukosal mice ability to repair postradiation damages is the basis of these regularities

  15. Metals far from equilibrium: From shocks to radiation damage

    CERN Document Server

    Bringa, E M; Caturla, M J; Stoelken, J; Kalantar, D

    2003-01-01

    Shock waves and high-energy particle radiation can each drive materials far from thermodynamic equilibrium and enable novel scenarios in the processing of materials. A large number of theoretical and experimental studies of shock deformation have been performed on polycrystalline materials, but shock deformation in single crystals has only recently been studied in some detail. We present molecular dynamics (MD) simulations of the shock response of single crystal copper, modeled using an embedded atom potential that reproduces both defect formation and high pressure behavior. Shock-induced plasticity will also be discussed. Predicting the in-service response of ferritic alloys in future fusion energy environments requires a detailed understanding of the mechanisms of defect accumulation and microstructure evolution in harsh radiation environments, which include a high level of He generation concurrent with primary damage production. The second half of this paper describes results of atomistic MD and kinetic Mo...

  16. Compensation of radiation damages for SOI pixel detector via tunneling

    CERN Document Server

    Yamada, Miho; Kurachi, Ikuo

    2015-01-01

    We are developing monolithic pixel detectors based on SOI technology for high energy physics, X-ray applications and so on.To employ SOI pixel detector on such radiation environments, we have to solve effects of total ionization damages (TID) for transistors which are enclosed in oxide layer.The holes which are generated and trapped in the oxide layers after irradiation affect characteristics of near-by transistors due to its positive electric field.Annealing and radiation of ultraviolet are not realistic to remove trapped holes for a fabricated detector due to thermal resistance of components and difficulty of handling. We studied compensation of TID effects by tunneling using a high-voltage. For decrease of trapped holes, applied high-voltage to buried p-well which is under oxide layer to inject the electrons into the oxide layer.In this report, recent progress of this study is shown.

  17. Molecular dynamics simulation of radiation damage cascades in diamond

    Energy Technology Data Exchange (ETDEWEB)

    Buchan, J. T. [Department of Physics and Astronomy, Curtin University, Perth, Western Australia 6845 (Australia); Robinson, M. [Nanochemistry Research Institute, Curtin University, Perth, Western Australia 6845 (Australia); Christie, H. J.; Roach, D. L.; Ross, D. K. [Physics and Materials Research Centre, School of Computing, Science and Engineering, University of Salford, Salford, Greater Manchester M5 4WT (United Kingdom); Marks, N. A. [Department of Physics and Astronomy, Curtin University, Perth, Western Australia 6845 (Australia); Nanochemistry Research Institute, Curtin University, Perth, Western Australia 6845 (Australia)

    2015-06-28

    Radiation damage cascades in diamond are studied by molecular dynamics simulations employing the Environment Dependent Interaction Potential for carbon. Primary knock-on atom (PKA) energies up to 2.5 keV are considered and a uniformly distributed set of 25 initial PKA directions provide robust statistics. The simulations reveal the atomistic origins of radiation-resistance in diamond and provide a comprehensive computational analysis of cascade evolution and dynamics. As for the case of graphite, the atomic trajectories are found to have a fractal-like character, thermal spikes are absent and only isolated point defects are generated. Quantitative analysis shows that the instantaneous maximum kinetic energy decays exponentially with time, and that the timescale of the ballistic phase has a power-law dependence on PKA energy. Defect recombination is efficient and independent of PKA energy, with only 50% of displacements resulting in defects, superior to graphite where the same quantity is nearly 75%.

  18. Molecular dynamics simulation of radiation damage cascades in diamond

    International Nuclear Information System (INIS)

    Radiation damage cascades in diamond are studied by molecular dynamics simulations employing the Environment Dependent Interaction Potential for carbon. Primary knock-on atom (PKA) energies up to 2.5 keV are considered and a uniformly distributed set of 25 initial PKA directions provide robust statistics. The simulations reveal the atomistic origins of radiation-resistance in diamond and provide a comprehensive computational analysis of cascade evolution and dynamics. As for the case of graphite, the atomic trajectories are found to have a fractal-like character, thermal spikes are absent and only isolated point defects are generated. Quantitative analysis shows that the instantaneous maximum kinetic energy decays exponentially with time, and that the timescale of the ballistic phase has a power-law dependence on PKA energy. Defect recombination is efficient and independent of PKA energy, with only 50% of displacements resulting in defects, superior to graphite where the same quantity is nearly 75%

  19. Radiation damage of transition metal carbides. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, G.

    1991-12-31

    In this grant period we have investigated electrical properties of transition metal carbides and radiation-induced defects produced by low-temperature electron irradiation in them. Special attention has been given to the composition VC{sub 0.88} in which the vacancies on the carbon sublattice of this fcc crystal order to produce a V{sub 8}C{sub 7} superlattice. The existence of this superlattice structure was found to make the crystal somewhat resistant to radiation damage at low doses and/or at ambient temperature. At larger doses significant changes in the resistivity are produced. Annealing effects were observed which we believe to be connected with the reconstitution of the superlattice structure.

  20. Medicinal protection with Chinese herb-compound against radiation damage

    International Nuclear Information System (INIS)

    Experiments were carried out on mice and the subjects irradiated for cancer therapy to evaluate the protective efficacy of a Chinese medicinal herb-compound (CMHC). The lethality and the degree of leucopenia caused by radiation in mice medicated with CMHC were significantly less in comparison with control mice (p less than 0.01 and p less than 0.001, respectively). CMHC significantly improved the WBC and the thrombocytes in irradiated workers (p less than 0.01 and p less than 0.001, respectively). The WBC count of 40 patients under radiotherapy while treated with CMHC recovered from 3450 +/- 77/c.mm to 5425 +/- 264/c.mm (p less than 0.001); whereas, in the control group, without any medication, the WBC count dropped significantly (p less than 0.001). Our results revealed the applicabilities of CMHC in protection against radiation damage in spaceflight and in other fields

  1. Medicinal protection with Chinese herb-compound against radiation damage

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, R.J.; Qian, J.K.; Yang, G.H.; Wang, B.Z.; Wen, X.L. (Institute of Space Medico-Engineering, Beijing (China))

    1990-08-01

    Experiments were carried out on mice and the subjects irradiated for cancer therapy to evaluate the protective efficacy of a Chinese medicinal herb-compound (CMHC). The lethality and the degree of leucopenia caused by radiation in mice medicated with CMHC were significantly less in comparison with control mice (p less than 0.01 and p less than 0.001, respectively). CMHC significantly improved the WBC and the thrombocytes in irradiated workers (p less than 0.01 and p less than 0.001, respectively). The WBC count of 40 patients under radiotherapy while treated with CMHC recovered from 3450 +/- 77/c.mm to 5425 +/- 264/c.mm (p less than 0.001); whereas, in the control group, without any medication, the WBC count dropped significantly (p less than 0.001). Our results revealed the applicabilities of CMHC in protection against radiation damage in spaceflight and in other fields.

  2. Amelioration of radiation damage by pentoxifylline treatment in rats

    International Nuclear Information System (INIS)

    Pentoxifylline (PTX) is a methylxanthine derivative used to treat vascular diseases. It has antioxidant properties, an anti- tumour necrosis factor alpha (TNFα) effect, increase erythrocyte flexibility and vasodilatation. An agent that increases blood flow and tissue oxygen content may contribute to enhanced healing of soft tissue, and inhibit inflammatory reactions. The mechanism of action of the anti-oxidant effect of pentoxifylline is not yet clear and it is an interesting field to explore. This study has investigated the antioxidant pathways through which PTX treatment (1200 mg/ l in drinking water) exerts its effect on radiation-induced changes. Blood reduced glutathione (GSH), glutathione peroxidase (GSH-PX) and serum catalase (CAT), MDA, xanthine oxidase (XO) and xanthine dehydrogenase (XDH), total protein, albumin, uric acid, advanced oxidation protein products (AOPP) and ascorbyl radical (AsR) were measured in female rats. Animals were divided into: Group 1: control, Group 2: administrated PTX for 8 days. Group 3: Exposed to fractionated radiation at the dose level of 4 Gy (2 Gy every 4 days) for 8 days and Group 4: received PTX two h post the onset of irradiation (4 Gy fractionated) till the end of the experiment. All animals were inspected after 8 days from the beginning of the experiment. Fractionated 4 Gy whole body gamma irradiation induced oxidative damage manifested in the significant decreases in blood GSH content, GSH-PX and CAT activities, total protein, albumin, uric acid, and XDH. Conversely, significant elevations were detected in plasma MDA, AOPP and AsR contents as well as XO activity. PTX treatment ameliorated radiation induced oxidative damage through its antioxidant properties and free radical scavenging ability that is partially mediated through inhibition of xanthine oxidase thus could play a role in regulating radiation complications.

  3. Role of Oxidative Damage in Radiation-Induced Bone Loss

    Science.gov (United States)

    Schreurs, Ann-Sofie; Alwood, Joshua S.; Limoli, Charles L.; Globus, Ruth K.

    2014-01-01

    During prolonged spaceflight, astronauts are exposed to both microgravity and space radiation, and are at risk for increased skeletal fragility due to bone loss. Evidence from rodent experiments demonstrates that both microgravity and ionizing radiation can cause bone loss due to increased bone-resorbing osteoclasts and decreased bone-forming osteoblasts, although the underlying molecular mechanisms for these changes are not fully understood. We hypothesized that excess reactive oxidative species (ROS), produced by conditions that simulate spaceflight, alter the tight balance between osteoclast and osteoblast activities, leading to accelerated skeletal remodeling and culminating in bone loss. To test this, we used the MCAT mouse model; these transgenic mice over-express the human catalase gene targeted to mitochondria, the major organelle contributing free radicals. Catalase is an anti-oxidant that converts reactive species, hydrogen peroxide into water and oxygen. This animal model was selected as it displays extended lifespan, reduced cardiovascular disease and reduced central nervous system radio-sensitivity, consistent with elevated anti-oxidant activity conferred by the transgene. We reasoned that mice overexpressing catalase in mitochondria of osteoblast and osteoclast lineage cells would be protected from the bone loss caused by simulated spaceflight. Over-expression of human catalase localized to mitochondria caused various skeletal phenotypic changes compared to WT mice; this includes greater bone length, decreased cortical bone area and moment of inertia, and indications of altered microarchitecture. These findings indicate mitochondrial ROS are important for normal bone-remodeling and skeletal integrity. Catalase over-expression did not fully protect skeletal tissue from structural decrements caused by simulated spaceflight; however there was significant protection in terms of cellular oxidative damage (MDA levels) to the skeletal tissue. Furthermore, we

  4. Radiation damage of biomolecules (RADAM) database development: current status

    International Nuclear Information System (INIS)

    Ion beam therapy offers the possibility of excellent dose localization for treatment of malignant tumours, minimizing radiation damage in normal tissue, while maximizing cell killing within the tumour. However, as the underlying dependent physical, chemical and biological processes are too complex to treat them on a purely analytical level, most of our current and future understanding will rely on computer simulations, based on mathematical equations, algorithms and last, but not least, on the available atomic and molecular data. The viability of the simulated output and the success of any computer simulation will be determined by these data, which are treated as the input variables in each computer simulation performed. The radiation research community lacks a complete database for the cross sections of all the different processes involved in ion beam induced damage: ionization and excitation cross sections for ions with liquid water and biological molecules, all the possible electron – medium interactions, dielectric response data, electron attachment to biomolecules etc. In this paper we discuss current progress in the creation of such a database, outline the roadmap of the project and review plans for the exploitation of such a database in future simulations.

  5. Analysis of radiation damage in on-orbit solar array of Venus explorer Akatsuki

    International Nuclear Information System (INIS)

    This paper describes an analysis of radiation damage in solar array of Venus explorer Akatsuki observed on orbit. The output voltage of the solar array have shown sudden drops, which are most reasonably associated with radiation damage, three times since its launch. The analysis of these radiation damages is difficult, because no direct observation data of the spectra and the amount of the high-energy particles is available. We calculated the radiation damage using the relative damage coefficient (RDC) method assuming a typical spectral shape of protons. (author)

  6. In situ reactor radiation-induced attenuation in sapphire optical fibers heated up to 1000 °C

    International Nuclear Information System (INIS)

    The purpose of this work was to determine the suitability of using instrumentation utilizing sapphire optical fibers in a high temperature nuclear reactor environment. For this, the broadband (500–2200 nm, or 0.56–2.48 eV) optical transmission in commercially available sapphire optical fibers was monitored in situ prior to, during, and after reactor irradiation. Portions of the sapphire fibers were heated to temperatures up to 1000 °C during irradiation. The sapphire fibers were irradiated, mostly at a neutron flux of 5.0 × 1011 n/cm2/s and a gamma dose rate of 28 kGy/h (dose in sapphire), to a total neutron fluence of 6.4 × 1016 n/cm2 and total gamma dose on the order of 1 MGy. Results were generally consistent with the results of previous in situ measurements of the transmission in unheated sapphire fibers during reactor irradiation. Added attenuation at 850, 1300, and 1550 nm, appears to be limited by the growth of radiation-induced defect centers that are located in the ultra violet to the visible range and is therefore less at 1300 and 1550 nm than at 850 nm. A linear increase in attenuation, due to displacement damage effects, was observed with increased irradiation time at constant reactor power. However, the rate of increase of the added attenuation during constant power reactor irradiation monotonically decreased with increasing temperature up to 1000 °C, with the most significant decrease occurring between 300 and 600 °C. Additional calculations predicted that the majority of (if not all of) the observed increases in attenuation during irradiation at 600 and 1000 °C were due to effects in the unheated sections of the irradiated sapphire fibers. These results suggest that, for a reactor radiation environment similar to that tested in this work, heating sapphire fibers to temperatures of 600 °C or greater during irradiation would significantly reduce (or possibly eliminate entirely) the rate of growth of the added attenuation in the sapphire

  7. Mass attenuation coefficients of X-rays in different barite concrete used in radiation protection as shielding against ionizing radiation

    International Nuclear Information System (INIS)

    The attenuation coefficient depends on the incident photon energy and the nature of the materials. In order to minimize exposure to individuals. Barite concrete has been largely used as a shielding material in installations housing gamma radiation sources as well as X-ray generating equipment. This study was conducted to evaluate the efficacy of different mixtures of barite concrete for shielding in diagnostic X-ray rooms. The mass attenuation coefficient (μ/ρ). The mass attenuation coefficients have been measured by employing the CdTe detector model XR-100T. The distance between the source and the exposed surface of all samples was measured by SSD light indicator of machine which was 350 cm. The slope of the linear plot of the intensity transmitted versus specimen thickness would yield the attenuation coefficient. The mass attenuation coefficients (μ/ρ) were compared with the tabulations based upon the results of the XCOM program. The rectangular barite concrete blocks in different thicknesses from were used for the radiation attenuation test. The experimental values were compared with theoretical values WinXcom. The plots of the logarithm of transmitted intensity versus specimen thickness were linear for all the samples and the µ/ρ was obtained from the plots by linear regression over the 25%-2% transmission range, under good geometrical condition. There is a good agreement between theoretical and experimental values, within the 9%. In fact over the entire transmission range of 25-2% the experimental and theoretical values agree well for both the energies. (authors)

  8. Positron annihilation lifetime study of radiation-damaged natural zircons

    Science.gov (United States)

    Roberts, J.; Gaugliardo, P.; Farnan, I.; Zhang, M.; Vance, E. R.; Davis, J.; Karatchevtseva, I.; Knott, R. B.; Mudie, S.; Buckman, S. J.; Sullivan, J. P.

    2016-04-01

    Zircons are a well-known candidate waste form for actinides and their radiation damage behaviour has been widely studied by a range of techniques. In this study, well-characterised natural single crystal zircons have been studied using Positron Annihilation Lifetime Spectroscopy (PALS). In some, but not all, of the crystals that had incurred at least half of the alpha-event damage of ∼1019 α/g required to render them structurally amorphous, PALS spectra displayed long lifetimes corresponding to voids of ∼0.5 nm in diameter. The long lifetimes corresponded to expectations from published Small-Angle X-ray Scattering data on similar samples. However, the non-observation by PALS of such voids in some of the heavily damaged samples may reflect large size variations among the voids such that no singular size can be distinguished or. Characterisation of a range of samples was also performed using scanning electron microscopy, optical absorption spectroscopy, Raman scattering and X-ray scattering/diffraction, with the degree of alpha damage being inferred mainly from the Raman technique and X-ray diffraction. The observed void diameters and intensities of the long lifetime components were changed somewhat by annealing at 700 °C; annealing at 1200 °C removed the voids entirely. The voids themselves may derive from He gas bubbles or voids created by the inclusion of small quantities of organic and hydrous matter, notwithstanding the observation that no voidage was evidenced by PALS in two samples containing hydrous and organic matter.

  9. Radiation damages in chemical components of organic scintillator detectors

    International Nuclear Information System (INIS)

    Samples containing PPO (1%, g/ml), diluted in toluene, they were irradiated in a 60Co irradiator (6.46 kGy/h) at different doses. The PPO concentration decay bi-exponentially with the dose, generating the degradation products: benzoic acid, benzamide and benzilic alcohol. The liquid scintillator system was not sensitive to the radiation damage until 20 kGy. Otherwise, the pulse height analysis showed that dose among 30 to 40 kGy generate significant loss of quality of the sensor (liquid scintillating) and the light yield was reduced in half with the dose of (34.04 ± 0.80) kGy. This value practically was confirmed by the photo peak position analysis that resulted D1/2 = (31.7 ± 1,4) kGy, The transmittance, at 360 nm, of the irradiated solution decreased exponentially. The compartmental model using five compartments (fast decay PPO, slow decay PPO, benzamide, benzoic acid and benzilic alcohol) it was satisfactory to explain the decay of the PPO in its degradation products in function of the dose. The explanation coefficient r2 = 0.985636 assures that the model was capable to explain 98.6% of the experimental variations. The Target Theory together with the Compartmental Analysis showed that PPO irradiated in toluene solution presents two sensitive molecular diameters both of them larger than the true PPO diameter. >From this analysis it showed that the radiolytic are generated, comparatively, at four toluene molecules diameter far from PPO molecules. For each one PPO-target it was calculated the G parameter (damage/100 eV). For the target expressed by the fast decay the G value was (418.4 ± 54.1) damages/100 eV, and for the slow decay target the G value was (54.5 ± 8.9) damages/100 eV. The energies involved in the chemical reactions were w (0.239 ± 0.031) eV/damage (fast decay) and w = (1 834 ± 0.301) eV/damage (slow decay). (author)

  10. Effect of Different Concrete Grade on Radiation Linear Attenuation Coefficient (μ)

    International Nuclear Information System (INIS)

    In calculating the quantity of absorption of radiation and its relationship with the thickness of a material, linear attenuation coefficient (μ) of the material is one of the parameters to be taken into account. For normal concrete, the (μ) varies depending on the type of radiation used, 0.105 cm-1 for Co-60 and 0.123 cm-1 for Cs-137. Value (μ) is used in the calculation of the radiation absorption for concrete material does not take into account factors such concrete grades. In this research, concrete with different grades (Grade 15, Grade 20, Grade 25, Grade 30, Grade 35, Grade 40) are designed and manufactured with reference to the mixing method described in British Standard. Then, the linear attenuation (μ) for each grade are measured using the radiation from the source Co-60 and Cs-137 sources. This paper describes and discusses the impact of differences in concrete grade of linear attenuation (μ) for Co-60 source/ source Cs-137 and its relationship with the compressive strength. (author)

  11. The repair mechanism for radiation damages by inorganic elements

    International Nuclear Information System (INIS)

    Previous studies of the authors showed that the death rate for mice after radiation exposure at a sub-lethal dose was significantly decreased by administration of a large amount of inorganic element such as Zn, Co, Mn, Mg, etc. Here, the cellular metabolism of Co element was investigated to elucidate the mechanism of such repair of radiation damages. The incorporation of 57-Co into the mouse spleen and bone marrow cells in vitro exposed to X-ray was compared to that into both cells from the mouse in vivo exposed to X-ray. The administration of Co carrier into the cells from unexposed mice increased the incorporation of Co into these cells and there were no differences in Co-incorporation between the cells exposed to radiation in vitro and in vivo. The Co-incorporation into the bone marrow cells was dose-dependently increased by either of in vitro and in vivo exposure, suggesting that there exists some cellular defense mechanism. For in vivo exposure, the amount of Co incorporation and also DNA synthesizing activity in spleen and bone marrow cells both decreased as increasing the amount of Co subcutaneously injected, but not given to the culture medium. To clarify cellular distribution of Co incorporated, the cells suspension was homogenized and centrifuged for cell fractionation. About 80% of incorporated Co was found in the cytoplasmic fraction and the other was in the membrane fraction, suggesting that Co element might be incorporated into some cellular components. (M.N.)

  12. Radiation damage to fusion reactor materials: Progress report, November 18, 1987 to July 15, 1988

    International Nuclear Information System (INIS)

    The activities in the past year have been focussed on four areas: radiation damage resistance of low activation ferritic steels; effect of residual oxygen on the radiation damage resistance of 316 SS; the response of Ni and Ni based alloys to high temperature radiation; the resistance of Cu alloys to high temperature irradiation. A brief summary of these projects is given in this paper

  13. XAFS studies of radiation damage in nuclear materials

    Science.gov (United States)

    Olive, Daniel Thomas

    The growing demand for nuclear energy places a high importance on the development of new materials capable of withstanding higher temperatures and harsher irradiation conditions than those used in existing reactors. By supporting the development of next generation reactors it also becomes possible to close the nuclear fuel cycle, greatly reducing the amount of waste sent for disposal in deep geologic repositories, where its interaction with the environment is also a matter of interest. In this thesis, X-ray absorption fine structure (XAFS) spectroscopy is used to investigate the local atomic structure of systems of interest to nuclear energy. First, two XAFS studies on environmental materials are presented. Granular activated carbon (GAC) was treated with iron to improve its water remediation properties, specifically with respect to arsenic. XAFS was used to determine the nature of iron coating on the GAC surface, and the method of arsenic bonding to the treated surface. Next, a neodymium precipitate from solubility studies carried out for the Waste Isolation Pilot Plant (WIPP) was analyzed. Neodymium was used as an analog for plutonium in brine solutions. XAFS fitting indicated that the neodymium substituted for calcium in a gypsum lattice, providing information useful for future geochemical modeling. XAFS was also used to study radiation damage in materials. A candidate material for advanced reactor structural materials, modified 9Cr--1Mo, was irradiated to 1, 4, and 10 displacements per atom (dpa). XAFS analyses were performed on the Fe, Mo, and Nb K-edges. Irradiation caused a reduction in coordination for all three elements, but the exact behavior was element specific. Damage around Fe atoms was linear with dose, while damage around Mo atoms saturated at or before 1 dpa. XAFS was shown to provide a useful atomic level description of radiation damage for a complex alloy system. Finally, zirconium carbide and zirconium nitride, candidate materials for advanced

  14. Computer simulations of radiation damage in protein crystals; Simulationsrechnungen zu Strahlenschaeden an Proteinkristallen

    Energy Technology Data Exchange (ETDEWEB)

    Zehnder, M.

    2007-03-15

    The achievable resolution and the quality of the dataset of an intensity data collection for structure analysis of protein crystals with X-rays is limited among other factors by radiation damage. The aim of this work is to obtain a better quantitative understanding of the radiation damage process in proteins. Since radiation damage is unavoidable it was intended to look for the optimum ratio between elastically scattered intensity and radiation damage. Using a Monte Carlo algorithm physical processes after an inelastic photon interaction are studied. The main radiation damage consists of ionizations of the atoms through the electron cascade following any inelastic photon interaction. Results of the method introduced in this investigation and results of an earlier theoretical studies of the influence of Auger-electron transport in diamond are in a good agreement. The dependence of the radiation damage as a function of the energy of the incident photon was studied by computer-aided simulations. The optimum energy range for diffraction experiments on the protein myoglobin is 10-40 keV. Studies of radiation damage as a function of crystal volume and shape revealed that very small plate or rod shaped crystals suffer less damage than crystals formed like a cube with the same volume. Furthermore the influence of a few heavy atoms in the protein molecule on radiation damage was examined. Already two iron atoms in the unit cell of myoglobin increase radiation damage significantly. (orig.)

  15. Insulating epoxy/barite and polyester/barite composites for radiation attenuation.

    Science.gov (United States)

    El-Sarraf, M A; El-Sayed Abdo, A

    2013-09-01

    A trial has been made to create insulating Epoxy/Barite (EP/Brt) (ρ=2.85 g cm(-3)) and Crosslinked Unsaturated Polyester/Barite (CUP/Brt) (ρ=3.25 g cm(-3)) composites with radiation attenuation and shielding capabilities. Experimental work regarding mechanical and physical properties was performed to study the composites integrity for practical applications. The properties were found to be reasonable. Radiation attenuation properties have been carried out using emitted collimated beam from a fission (252)Cf (100 µg) neutron source, and the neutron-gamma spectrometer with stilbene scintillator. The pulse shape discriminating (P.S.D) technique based on the zero cross-over method was used to discriminate between neutron and gamma-ray pulses. Thermal neutron fluxes, measured using the BF3 detector and thermal neutron detection system, were used to plot the attenuation relations. The fast neutron macroscopic effective removal cross-section ΣR, gamma ray total attenuation coefficient µ and thermal neutron macroscopic cross-section Σ have been evaluated. Theoretical calculations have been achieved using MCNP-4C2 code to calculate ΣR, µ and Σ. Also, MERCSF-N program was used to calculate macroscopic effective removal cross-section ΣR. Measured and calculated results have been compared and were found to be in reasonable agreement. PMID:23722071

  16. Measurement of the linear attenuation coefficients of breast tissues by synchrotron radiation computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Chen, R C; Xiao, T Q [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai (China); Longo, R; Arfelli, F; Castelli, E [Department of Physics, University of Trieste, Trieste (Italy); Rigon, L; Dreossi, D; Menk, R-H; Vallazza, E [INFN, Sezione di Trieste, Trieste (Italy); Zanconati, F; De Pellegrin, A, E-mail: rongchang.chen@gmail.co [Department of Pathologic Anatomy, University of Trieste, Trieste (Italy)

    2010-09-07

    The measurement of the linear attenuation coefficients of breast tissues is of fundamental importance in the field of breast x-ray diagnostic imaging. Different groups have evaluated the linear attenuation coefficients of breast tissues by carrying out direct attenuation measurements in which the specimens were thin and selected as homogeneous as possible. Here, we use monochromatic and high-intensity synchrotron radiation computed tomography (SR CT) to evaluate the linear attenuation coefficients of surgical breast tissues in the energy range from 15 to 26.5 keV. X-ray detection is performed by a custom digital silicon micro-strip device, developed in the framework of the PICASSO INFN experiment. Twenty-three human surgical breast samples were selected for SR CT and histological study. Six of them underwent CT, both as fresh tissue and after formalin fixation, while the remaining 17 were imaged only as formalin-fixed tissues. Our results for fat and fibrous tissues are in good agreement with the published values. However, in contrast to the published data, our measurements show no significant differences between fibrous and tumor tissues. Moreover, our results for fresh and formalin-fixed tissues demonstrate a reduction of the linear attenuation coefficient for fibrous and tumor tissues after fixation.

  17. Measurement of the linear attenuation coefficients of breast tissues by synchrotron radiation computed tomography

    International Nuclear Information System (INIS)

    The measurement of the linear attenuation coefficients of breast tissues is of fundamental importance in the field of breast x-ray diagnostic imaging. Different groups have evaluated the linear attenuation coefficients of breast tissues by carrying out direct attenuation measurements in which the specimens were thin and selected as homogeneous as possible. Here, we use monochromatic and high-intensity synchrotron radiation computed tomography (SR CT) to evaluate the linear attenuation coefficients of surgical breast tissues in the energy range from 15 to 26.5 keV. X-ray detection is performed by a custom digital silicon micro-strip device, developed in the framework of the PICASSO INFN experiment. Twenty-three human surgical breast samples were selected for SR CT and histological study. Six of them underwent CT, both as fresh tissue and after formalin fixation, while the remaining 17 were imaged only as formalin-fixed tissues. Our results for fat and fibrous tissues are in good agreement with the published values. However, in contrast to the published data, our measurements show no significant differences between fibrous and tumor tissues. Moreover, our results for fresh and formalin-fixed tissues demonstrate a reduction of the linear attenuation coefficient for fibrous and tumor tissues after fixation.

  18. Seismic Wave Attenuation Estimated from Tectonic Tremor and Radiated Energy in Tremor for Various Subduction Zones

    Science.gov (United States)

    Yabe, S.; Baltay, A.; Ide, S.; Beroza, G. C.

    2013-12-01

    Ground motion prediction is an essential component of earthquake hazard assessment. Seismic wave attenuation with distance is an important, yet difficult to constrain, factor for such estimation. Using the empirical method of ground motion prediction equations (GMPEs), seismic wave attenuation with distance, which includes both the effect of anelastic attenuation and scattering, can be estimated from the distance decay of peak ground velocity (PGV) or peak ground acceleration (PGA) of ordinary earthquakes; however, in some regions where plate-boundary earthquakes are infrequent, such as Cascadia and Nankai, there are fewer data with which to constrain the empirical parameters. In both of those subduction zones, tectonic tremor occurs often. In this study, we use tectonic tremor to estimate the seismic wave attenuation with distance, and in turn use the attenuation results to estimate the radiated seismic energy of tremor. Our primary interest is in the variations among subduction zones. Ground motion attenuation and the distribution of released seismic energy from tremors are two important subduction zone characteristics. Therefore, it is very interesting to see whether there are variations of these parameters in different subduction zones, or regionally within the same subduction zone. It is also useful to estimate how much energy is released by tectonic tremor from accumulated energy to help understand subduction dynamics and the difference between ordinary earthquakes and tremor. We use the tectonic tremor catalog of Ide (2012) in Nankai, Cascadia, Mexico and southern Chile. We measured PGV and PGA of individual tremor bursts at each station. We assume a simple GMPE relationship and estimate seismic attenuation and relative site amplification factors from the data. In the Nankai subduction zone, there are almost no earthquakes on the plate interface, but intra-slab earthquakes occur frequently. Both the seismic wave attenuation with distance and the site

  19. ATEN, a didactic program to study gamma radiation attenuation through matter

    CERN Document Server

    Paniagua, J; Rio, M D; Jiménez, A; Baeza, A; Miro, C

    1995-01-01

    A simulation model is described, which is based on the Monte-Carlo technique, for the computer study of the attenuation which gamma radiation undergoes as it interacts with matter. The interaction modes that were considered are exclusively the photoelectric, Compton, and pair production effects. A computer program, ATEN, has been developed for this model, which allows one to obtain the attenuation coefficient of an absorbing material for gamma radiation of known energy, using cross sections of those processes considered in the model for energies between 0.1 and 10 MeV. ATEN was developed for didactic purposes and was designed to be used as an interesting support for laboratory practical classes for undergraduates in their first university courses. (author)

  20. Schistosoma mansoni: migration potential of normal and radiation attenuated parasites in naive guinea pigs

    International Nuclear Information System (INIS)

    Compressed tissue autoradiography using [75Se]selenomethionine labelled parasites has been used to investigate the migration potential of normal and radiation attenuated cercariae of Schistosoma mansoni in naive guinea pigs. By Day 14 after infection. 44% of normal parasites were detected as reduced silver foci in the liver; this value corresponded well with the number of liver parasites recovered by retrograde perfusion of the hepatic portal system on Day 42 (42% of the challenge). In contrast, cercariae subjected to 50 krad of gamma irradiation failed to migrate out of the skin. The migration capacity of 20 krad irradiated parasites was less severely affected in that about half of the challenge parasites reached the lungs, but virtually none moved to the liver. These data are discussed in relation to the kinetics of immunity induced in guinea pigs by infection or vaccination with normal or radiation attenuated parasites

  1. Schistosoma mansoni: migration potential of normal and radiation attenuated parasites in naive guinea pigs

    Energy Technology Data Exchange (ETDEWEB)

    Kamiya, H.; McLaren, D.J.

    1987-02-01

    Compressed tissue autoradiography using (75Se)selenomethionine labelled parasites has been used to investigate the migration potential of normal and radiation attenuated cercariae of Schistosoma mansoni in naive guinea pigs. By Day 14 after infection. 44% of normal parasites were detected as reduced silver foci in the liver; this value corresponded well with the number of liver parasites recovered by retrograde perfusion of the hepatic portal system on Day 42 (42% of the challenge). In contrast, cercariae subjected to 50 krad of gamma irradiation failed to migrate out of the skin. The migration capacity of 20 krad irradiated parasites was less severely affected in that about half of the challenge parasites reached the lungs, but virtually none moved to the liver. These data are discussed in relation to the kinetics of immunity induced in guinea pigs by infection or vaccination with normal or radiation attenuated parasites.

  2. ATEN, a didactic program to study gamma radiation attenuation through matter

    International Nuclear Information System (INIS)

    A simulation model is described, which is based on the Monte-Carlo technique, for the computer study of the attenuation which γ radiation undergoes as it interacts with matter. The interaction modes that were considered are exclusively the photoelectric, Compton, and pair production effects. A computer program, ATEN, has been developed for this model, which allows one to obtain the attenuation coefficient of an absorbing material for gamma radiation of known energy, using cross sections of those processes considered in the model for energies between 0.1 and 10 MeV. ATEN was developed for didactic purposes and was designed to be used as an interesting support for laboratory practical classes for undergraduates in their first university courses. (author)

  3. Inhibition of a SNARE sensitive pathway in astrocytes attenuates damage following stroke

    OpenAIRE

    Hines, Dustin J.; Haydon, Philip G.

    2013-01-01

    A strong body of research has defined the role of excitotoxic glutamate in animal models of brain ischemia and stroke, however clinical trials of glutamate receptor antagonists have demonstrated their limited capacity to prevent brain damage following ischemia. We propose that astrocyte-neuron signaling represents an important modulatory target that may be useful in mediating damage following stroke. To assess the impact of astrocyte signaling on damage following stroke we have used the astro...

  4. Effect of aqueous extract of saffron (crocus sativus L.) against gamma radiation-induced skeletal muscles damage in rats

    International Nuclear Information System (INIS)

    Muscular strength is important in sport as well as in daily activities. Reactive oxygen species (ROS) and oxidative damage are the most important factors in radiation-induced acute damage to muscle tissue. Saffron, obtained from dried stigmas of Crocus sativus L. (Iridaceae), is a highly valued spice, commonly used in flavouring and food colouring in different parts of the world and is known to possess the richest source of carotenoids. The present study was designed to investigate the efficacy of an aqueous extract of saffron to protect against radiation-induced oxidative damage in rat's skeletal muscle. Saffron was supplemented orally, via gavages to rats at a dose of 80 mg/ kg body wt/ day for 2 week pre- and 1 week post-exposure to 5 Gy (one shot dose) of whole body gamma-irradiation. Animals were sacrificed 1, 2 and 3 weeks post radiation exposure. The results revealed that whole body gamma-irradiation of rats induce oxidative stress in skeletal muscles obvious by significant elevation in the level of thiobarbituric acid reactive substances associated with significant decreases in superoxide dismutase and catalase activities. Also, radiation-induces skeletal muscles damage evidenced by significant decreases in the level of pyruvic acid, creatine phosphokinase, glutamate dehydrogenase and glucose-6-phosphate dehydrogenase activities as well as significant increases in lactic acid, total iron, and copper and calcium levels. Saffron treated-irradiated rats showed significantly less severe damage and remarkable improvement in all the measured parameters, compared to irradiated rats. It could be concluded that saffron by attenuating radiation-induced oxidative stress might play a role in maintaining skeletal muscle integrity.

  5. The Flavonoid Rutin Attenuates the Radiation Induced Biochemical Disorders in Female Rats

    International Nuclear Information System (INIS)

    Nowadays increasing attention has been given to the role of free radicals generated through oxidative stress. Tissue damage is associated with alterations in oxidative damage markers such as lipid peroxidation, protein oxidation, glutathione (GSH) level and gamma glutamyl transpeptidase (g GT) activity. Many radical scavengers, interestingly naturally occurring antioxidants flavonoids, have been found to be effective in inhibiting the oxidative damage. In the present study female Sprague Dawely rats (140-150 g) were exposed to whole body gamma irradiation (shot dose, 6.5 Gy). The flavonoid rutin, widely distributed in most vegetables, was administrated orally (1.064 mmol/kg body wt) up to 2 weeks before gamma irradiation of rats. Blood samples were taken 1 and 14 days post radiation exposure. The data revealed deleterious damage of radiation exposure which is manifested in significant acceleration in lipid peroxidation (as malon-dialdehyde, MDA content) and protein oxidation (as carbonyl group). On the other hand, the data recorded imbalance in the redox status which is noticed in the significant inhibition of reduced glutathione (GSH) and elevation in gamma GT activity level. Administration of rutin before radiation exposure ameliorated, to a great extent the damaging effects of radiation in the assayed parameters indicating its beneficial role in scavenging free radicals and reactive oxygen species as a promising antioxidant

  6. Biological rhythms for rehabilitation of radiation damage of population

    International Nuclear Information System (INIS)

    Considerable disturbances in biological eurhythmycal structure of redoracu were discovered for people living in Borodulikha area of the Semipalatinsk test site. The deep desynchronise may result in a development of the cardiovascular, bronco-pulmonary, endocrine, oncologic, neuro psychic diseases. A method to correct the biological eurhythmycal structure was developed. Homeopathic doses of melatonin ('rhythm driver' managing the most regenerating and immune systems) and uthynol (promoting production of dehydroepiandrosterone of maternal prehormone of 27 hormones) were used to provide the general correction. The endocrine diseases are not practically subjected to the homeopathic correction. The sub correction was sometimes carried out after 5 months. The developed methods of rehabilitation of the radiation damages are unique, since they allow performing the homeopathic correction using the acupuncture monitoring

  7. Radiation damage test of position sensitive silicon detectors

    International Nuclear Information System (INIS)

    A study of radiation damage of position sensitive silicon detectors (PSDs), for use as a position monitor of high energy heavy ion beams, was carried out. It is revealed that the position linearity of the standard PSD is strongly affected even by an absorbed dose around 100 Gy. The reason of the distortion of position linearity was considered to be a positive charge build-up in the SiO2 layer covering the PSD. To overcome the problem, new types of PSDs have been developed raising impurity density in the resistive layer and removing the SiO2 layer. A PSD with a distortion of less than 100 μm over an effective area of 13 mm x 13 mm is obtained which is usable as a heavy ion beam monitor. (orig.)

  8. Radiation damage in a rock salt nuclear waste repository

    International Nuclear Information System (INIS)

    A model has been developed which provides a fundamental understanding of the build-up of radiation damage in NaCl. This model is based on kinetic rate reactions and takes into account the effect of impurities and the colloid nucleation stage on the growth of metallic Na colloids. With this model, we have calculated the amounts of NaCl that can be converted into metallic Na and molecular Cl2 for various options for repository design and intermediate storage times. It is shown that the concentrations of these defect aggregates, even very close to the high-level radioactive waste (HLW) containers with steel wall thickness of 5 mm, will be limited to a few mole %. (orig./HP)

  9. Development of resistant materials to beam impact and radiation damage

    Science.gov (United States)

    Kawai, Masayoshi; Kokawa, Hiroyuki; Okamura, Hiroshi; Kawasaki, Akira; Yamamura, Tsutomu; Hara, Nobuyoshi; Akao, Noboru; Futakawa, Masatoshi; Kikuchi, Kenji

    2006-09-01

    Materials that have strong resistance to both beam impact (or shock-wave) and radiation damage are required for the beam target of an intense accelerator and space applications. Recently, Futakawa et al. found in their experiments that Kolsterising specimens have a stronger resistance to pitting than SS316 CW. A similar effect can be expected for other hardening treatments, and new material development is hopeful. Accordingly, we have started the development of high-performance materials by organizing the project team from KEK, JAEA and universities. In this paper, the scope of the project is introduced. Recent topics involve the development of intergranular crack (IGC)-resistant austenitic stainless-steel, AlN-TiN ceramics and cladding techniques of thin tantalum or CrN film on a tungsten target by means of a molten-salt method and ion-beam-enhanced deposition. New observations on corrosion resistance are presented.

  10. Ultraviolet radiation-mediated damage to cellular DNA

    Energy Technology Data Exchange (ETDEWEB)

    Cadet, Jean [Laboratoire Lesions des Acides Nucleiques, Service de Chimie Inorganique et Biologique, CEA/DSM/Departement de Recherche Fondamentale sur la Matiere Condensee, CEA-Grenoble, 17, Av. des Martyrs, Grenoble Cedex 9 F-38054 (France)]. E-mail: jcadet@cea.fr; Sage, Evelyne [Institut Curie, CNRS/IC UMR 2027, Centre Universitaire, Orsay (France); Douki, Thierry [Laboratoire Lesions des Acides Nucleiques, Service de Chimie Inorganique et Biologique, CEA/DSM/Departement de Recherche Fondamentale sur la Matiere Condensee, CEA-Grenoble, 17, Av. des Martyrs, Grenoble Cedex 9 F-38054 (France)

    2005-04-01

    Emphasis is placed in this review article on recent aspects of the photochemistry of cellular DNA in which both the UVB and UVA components of solar radiation are implicated individually or synergistically. Interestingly, further mechanistic insights into the UV-induced formation of DNA photoproducts were gained from the application of new accurate and sensitive chromatographic and enzymic assays aimed at measuring base damage. Thus, each of the twelve possible dimeric photoproducts that are produced at the four main bipyrimidine sites can now be singled out as dinucleoside monophosphates that are enzymatically released from UV-irradiated DNA. This was achieved using a recently developed high-performance liquid chromatography-tandem mass spectrometry assay (HPLC-MS/MS) assay after DNA extraction and appropriate enzymic digestion. Interestingly, a similar photoproduct distribution pattern is observed in both isolated and cellular DNA upon exposure to low doses of either UVC or UVB radiation. This applies more specifically to the DNA of rodent and human cells, the cis-syn cyclobutadithymine being predominant over the two other main photolesions, namely thymine-cytosine pyrimidine (6-4) pyrimidone adduct and the related cyclobutyl dimer. UVA-irradiation was found to generate cyclobutane dimers at TT and to a lower extent at TC sites as a likely result of energy transfer mechanism involving still unknown photoexcited chromophore(s). Oxidative damage to DNA is also induced although less efficiently by UVA-mediated photosensitization processes that mostly involved {sup 1}O{sub 2} together with a smaller contribution of hydroxyl radical-mediated reactions through initially generated superoxide radicals.

  11. Measurement of 60CO gamma radiation induced attenuation in multimode step-index POF at 530 nm

    Directory of Open Access Journals (Sweden)

    Kovačević Milan S.

    2013-01-01

    Full Text Available As optical fibres are used ever more extensively in space applications, nuclear industry, medicine and high-energy physics experiments, it has become essential to investigate the influence of ionizing radiation on their characteristics. In this work, the radiation-induced attenuation at 530 nm is investigated experimentally in step-index multimode polymethyl-methacrylate plastic optical fibres exposed to low dose-rate gamma radiation. Cumulative doses ranged from 50 Gy to 500 Gy. The radiation induced attenuation has been empirically found to obey the power law RIA= aDb, where D is the total radiation dose and a and b are the constants determined by fitting.

  12. Radiation damage in proton-irradiated epitaxial silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Lange, Joern

    2009-07-15

    In this work radiation hardness of 75 {mu}m, 100 {mu}m and 150 {mu}m thick epitaxial silicon pad diodes of both standard and oxygenated material was investigated. Damage after 24 GeV/c proton irradiation in a 1MeV neutron equivalent fluence range between 10{sup 14} cm{sup -2} and 10{sup 16} cm{sup -2} was studied and isothermal annealing experiments at 80 C were carried out. Standard CV/IV measurements could be performed up to 4 x 10{sup 15} cm{sup -2}. The volume-normalised reverse current was found to increase linearly with fluence with a slope independent of the thickness and impurity concentration. However, due to large fluctuations the fluences had to be renormalised using the current-related damage parameter. Concerning the depletion voltage, nearly all materials remained at a moderate level up to 4 x 10{sup 15} cm{sup -2}. During short-term annealing acceptors annealed out, whereas others were introduced during the long-term annealing. The stable damage was characterised by donor removal at low fluences and fluence-proportional predominant donor introduction for highly irradiated diodes, depending on the oxygen level. No type inversion was observed. Time-resolved measurements with a new 670 nm laser-TCT setup made the determination of the trapping time constant with the charge correction method possible. The results agreed with expectations and showed a linear increase of trapping probability with fluence. The electric field exhibited a double peak structure in highly irradiated diodes. Charge collection efficiency measurements with {alpha}-particles were independent of oxygen concentration, but showed an improved efficiency for thinner diodes. A comparison to simulation revealed systematic discrepancies. A non-constant trapping time parameter was proposed as possible solution. (orig.)

  13. Radiation damage in proton-irradiated epitaxial silicon detectors

    International Nuclear Information System (INIS)

    In this work radiation hardness of 75 μm, 100 μm and 150 μm thick epitaxial silicon pad diodes of both standard and oxygenated material was investigated. Damage after 24 GeV/c proton irradiation in a 1MeV neutron equivalent fluence range between 1014 cm-2 and 1016 cm-2 was studied and isothermal annealing experiments at 80 C were carried out. Standard CV/IV measurements could be performed up to 4 x 1015 cm-2. The volume-normalised reverse current was found to increase linearly with fluence with a slope independent of the thickness and impurity concentration. However, due to large fluctuations the fluences had to be renormalised using the current-related damage parameter. Concerning the depletion voltage, nearly all materials remained at a moderate level up to 4 x 1015 cm-2. During short-term annealing acceptors annealed out, whereas others were introduced during the long-term annealing. The stable damage was characterised by donor removal at low fluences and fluence-proportional predominant donor introduction for highly irradiated diodes, depending on the oxygen level. No type inversion was observed. Time-resolved measurements with a new 670 nm laser-TCT setup made the determination of the trapping time constant with the charge correction method possible. The results agreed with expectations and showed a linear increase of trapping probability with fluence. The electric field exhibited a double peak structure in highly irradiated diodes. Charge collection efficiency measurements with α-particles were independent of oxygen concentration, but showed an improved efficiency for thinner diodes. A comparison to simulation revealed systematic discrepancies. A non-constant trapping time parameter was proposed as possible solution. (orig.)

  14. Dislocations and radiation damage in α-uranium

    International Nuclear Information System (INIS)

    Dislocations in α-uranium were studied by electron microscopy. Electropolishing of thin foils was performed at low temperature (-110 deg. C) to prevent oxidation. Burgers vectors of twins dislocations are defined. Interactions between slip and twinning are studied from both experimental and theoretical point of view. Samples irradiated at several burn-up were examined. In order to explain our micrographic results, and also all information gathered in literature about radiation damage in α-uranium, a coherent model is propound for the fission particles effects. We analyse the influences of parameters: temperature, dislocation density, impurity content. The number of point defects created by one initial fission is determined for pure and annealed metal. The importance of the self-anneal which occurs immediately in each displacement spike, and the anneal due to a new fission on the damage resulting from a previous fission, are estimated. The focussing distance in [100] direction is found to be about 1000 Angstrom, at 4 deg. K. (author)

  15. Dislocation dynamics modelling of radiation damage in thin films

    International Nuclear Information System (INIS)

    Transmission electron microscopy is a key tool for the extraction of information on radiation damage, the understanding of which is critical for materials development for nuclear fusion and fission reactors. Dislocations in TEM samples are subject to strong image forces, owing to the nanometric sample thicknesses, which may introduce artifacts in the damage analysis. Using dislocation dynamics, we elucidate the roles played by dislocation–surface interactions, dislocation–dislocation interactions and self-interactions due to climb for loop types observed in TEM. Comparisons with analytic solutions for a dislocation loop and an edge dislocation in a half-space are included, and the relationship between glide force and loop tilt examined. The parameters for convergence of the zero-traction boundary conditions are obtained, after which the evolution of dislocation structures in a thin film is studied. It is found that three main length scales govern the physical processes: the image force is governed by the distance of the loop from the surface and scales with the film thickness; the glide force is governed by the image stress as well as the loop–loop interaction stress which is in turn governed by the loop spacing L∼1/√ρ, where ρ is the loop density; finally, the climb force depends on the loop size. The three forces compete and their relative magnitudes define the evolution pathway of the dislocation structure. (paper)

  16. Dislocation dynamics modelling of radiation damage in thin films

    Science.gov (United States)

    Ferroni, Francesco; Tarleton, Edmund; Fitzgerald, Steven

    2014-06-01

    Transmission electron microscopy is a key tool for the extraction of information on radiation damage, the understanding of which is critical for materials development for nuclear fusion and fission reactors. Dislocations in TEM samples are subject to strong image forces, owing to the nanometric sample thicknesses, which may introduce artifacts in the damage analysis. Using dislocation dynamics, we elucidate the roles played by dislocation-surface interactions, dislocation-dislocation interactions and self-interactions due to climb for loop types observed in TEM. Comparisons with analytic solutions for a dislocation loop and an edge dislocation in a half-space are included, and the relationship between glide force and loop tilt examined. The parameters for convergence of the zero-traction boundary conditions are obtained, after which the evolution of dislocation structures in a thin film is studied. It is found that three main length scales govern the physical processes: the image force is governed by the distance of the loop from the surface and scales with the film thickness; the glide force is governed by the image stress as well as the loop-loop interaction stress which is in turn governed by the loop spacing L\\sim 1/\\sqrt{\\rho} , where ρ is the loop density; finally, the climb force depends on the loop size. The three forces compete and their relative magnitudes define the evolution pathway of the dislocation structure.

  17. Influence of radiation damage on krypton diffusion in silicon carbide

    Science.gov (United States)

    Friedland, E.; Hlatshwayo, T. T.; van der Berg, N. G.; Mabena, M. C.

    2015-07-01

    Diffusion of krypton in poly and single crystalline silicon carbide is investigated and compared with the previously obtained results for xenon, which pointed to a different diffusion mechanism than observed for chemically active elements. For this purpose 360 keV krypton ions were implanted in commercial 6H-SiC and CVD-SiC wafers at room temperature, 350 °C and 600 °C. Width broadening of the implantation profiles and krypton retention during isochronal and isothermal annealing up to temperatures of 1400 °C was determined by RBS-analysis, whilst in the case of 6H-SiC damage profiles were simultaneously obtained by α-particle channeling. Little diffusion and no krypton loss was detected in the initially amorphized and eventually recrystallized surface layer of cold implanted 6H-SiC during annealing up to 1200 °C. Above that temperature thermal etching of the implanted surface became increasingly important. No diffusion or krypton loss is detected in the hot implanted 6H-SiC samples during annealing up to 1400 °C. Radiation damage dependent grain boundary diffusion is observed at 1300 °C in CVD-SiC. The results seem to indicate, that the chemically inert noble gas atoms do not form defect-impurity complexes, which strongly influence the diffusion behavior of other diffusors in silicon carbide.

  18. Influence of radiation damage on krypton diffusion in silicon carbide

    International Nuclear Information System (INIS)

    Diffusion of krypton in poly and single crystalline silicon carbide is investigated and compared with the previously obtained results for xenon, which pointed to a different diffusion mechanism than observed for chemically active elements. For this purpose 360 keV krypton ions were implanted in commercial 6H-SiC and CVD-SiC wafers at room temperature, 350 °C and 600 °C. Width broadening of the implantation profiles and krypton retention during isochronal and isothermal annealing up to temperatures of 1400 °C was determined by RBS-analysis, whilst in the case of 6H-SiC damage profiles were simultaneously obtained by α-particle channeling. Little diffusion and no krypton loss was detected in the initially amorphized and eventually recrystallized surface layer of cold implanted 6H-SiC during annealing up to 1200 °C. Above that temperature thermal etching of the implanted surface became increasingly important. No diffusion or krypton loss is detected in the hot implanted 6H-SiC samples during annealing up to 1400 °C. Radiation damage dependent grain boundary diffusion is observed at 1300 °C in CVD-SiC. The results seem to indicate, that the chemically inert noble gas atoms do not form defect-impurity complexes, which strongly influence the diffusion behavior of other diffusors in silicon carbide

  19. Reinfection immunity in schistosomiasis. With special reference to immunity induced by radiation attenuated Cercariae

    Energy Technology Data Exchange (ETDEWEB)

    Kamiya, Haruo

    1987-07-01

    Schistosomiasis is one of the most important parasitic diseases in the world, especially in endemic areas of developing countries. This situation has prompted parasitologist to attempt intensive researches on immune mechanisms, especially those of reinfection immunity associated with eliminating challenge infection. The current knowledge of reinfection immunity against Schistosoma spp. infection was therefore reviewed briefly and discussed with special reference to our data on protective immune responses induced by radiation-attenuated cercarial infection. A recently developed technique of compressed organ autoradiography (COA) has contributed to assessing parasite attrition in immune animals following challenge infection. Our study using COA has demonstrated that major attrition of schistosomula from challenge infection occurs in the skin of CBA/Ca mice vaccinated with 20 Krad gamma radiation-attenuated cercariae of S. mansoni, while in both lungs and liver of similarly vaccinated guinea pig model. Furthermore, gamma-irradiation to cercariae affected their migration potential and surface-antigen profiles. The immunizing stimuli of gamma radiation-attenuated cercariae profoundly affected the expression of responsiveness in vaccinated animals. The change in antigenic profiles and migration potential of those vaccinating population was discussed in relation to the kinetics of reinfection immunity induced in vaccinated amimal models. These works might provide a base line data to develop a practical vaccine for schistosomiasis using defined antigens. It must be emphasized that these vaccines could serve as a practical prophylactic measure for schistosomiasis in the endemic areas, even if the vaccines fail to induce sterilizing immunity. (author). 141 refs.

  20. Micronuclei: sensitivity for the detection of radiation induced damage

    International Nuclear Information System (INIS)

    The in vitro cytokinesis-block (CB) micronucleus (MN) assay for human peripheral blood has been used extensively for the assessment of chromosomal damage induced by ionizing radiation and chemicals and considered a suitable biological dosimeter for estimating in vivo whole body exposures, particularly in the case of large scale radiation accidents. One of the major drawbacks of the MN assay is its reduced sensitivity for the detection of damage induced by low doses of low LET radiation, due to the high variability among the spontaneous MN frequencies. It is suggested that age, smoking habit and sex are the main confounding factors that contribute to the observed variability. Previous work in our laboratory, shows a significant positive correlation of the spontaneous and radiation induced MN frequencies with age and smoking habit, the latter being the strongest confounder. These findings led to in vitro studies of the dose-response relationships for smoking and non smoking donors evaluated separately, using 60Co γ rays. The objectives of the present work are: 1-To increase the amount of data of the dose-response relationships, using γ rays from a 60Co source, for smoking and non smoking donors, in order to find, if applicable, a correction factor for the calibration curve that takes into account the smoking habit of the individual in the case of accidental overexposure dose assessment, particularly in the low dose range. 2-To establish general conclusions on the current state of the technique. The sample for smoking and non smoking calibration curves was enlarged in the range of 0Gy to 2Gy. The fitting of both curves, performed up to the 2Gy dose, resulted in a linear quadratic model. MN distribution among bi nucleated cells was found to be over dispersed with respect to Poisson distribution, the average ratio of variance to mean being 1.13 for non smokers and 1.17 for smokers. Each fitted calibration curve, for smoking and non smoking donors, fell within the 95

  1. Plume attenuation of laser radiation during high power fiber laser welding

    International Nuclear Information System (INIS)

    The results of an in-situ plume-laser interaction measurement during welding of mild steel with a 5 kW ytterbium fiber laser are reported. A measurement of the attenuation of probe laser beam passing through the plume has allowed to estimate the plume characteristics like the size of the extinction area and the spatial distribution of the extinction coefficient. The power loss of the fiber laser radiation propagating through the whole plume length was calculated. Together with a measured temporal characteristics of extinction the result indicates a significant decreasing of the laser radiation stability, which can lead to the formation of the macroscopic welding defects

  2. Biomarkers of radiation or oxidative damage to DNA in cells

    International Nuclear Information System (INIS)

    Major efforts have been devoted during the last two decades to the development of chemical and biochemical assays aimed at monitoring oxidized bases within DNA. Until recently, the level of oxidized bases in cellular DNA was overestimated by factors varying from one to three orders of magnitude. The reasons of these inconsistencies are now identified. Thus, artifactual oxidation of nucleobases may occur during the silylation reaction prior to gas chromatography mass spectrometry analysis and to a lesser extent during DNA extraction. The use of the so-called chaotropic DNA extraction method together with chelating agents was found to significantly prevent spurious DNA oxidation to occur. HPLC separations coupled to either electrochemical detection or versatile electrospray ionization tandem-mass spectrometry appear to be appropriate analytical tools when at least 20 μg of DNA is available. Interestingly, up to 11 modified nucleosides and nucleobases including the four cis and trans diastereomers of 5,6- dihydroxy-5,6-dihydrothymidine, 5-formyl-2'-deoxyuridine, 5-(hydroxymethyl)-2'-deoxyuridine, and 5-hydroxy-2'-deoxyuridine, 8-oxo-7,8-dihydro-2'-deoxyguanosine, 8-oxo-7,8-dihydro-2'-deoxyadenosine together with related formamidopyrimidine derivatives were measured in the DNA of neoplastic human monocytes exposed to ionizing radiation using the latter assay. The association of base excision DNA repair enzymes including bacterial formamidopyrimidine glycosylase (Fpg) and endonuclease III (endo III) with the comet assay represents a better alternative for assessing low levels of base damage. The basal level of Fpg- and endo III-sensitive sites was found to be similar, close to 2.1 per 107 bases, within the DNA of human monocytes. The yields of the different classes of damage per Gy and 107 bases are the following: 0.48 Fpg-sensitive sites, 0.53 endo III-sensitive sites and 1.30 strand breaks (direct nicks and alkali-labile sites). Interestingly, the above three classes

  3. Radiation damage on p-type silicon detectors

    CERN Document Server

    Pirollo, S; Borchi, E; Bruzzi, M; Catacchini, E; Lazanu, S; Li, Z; Sciortino, S

    1999-01-01

    Two sets of p-type silicon (high resistivity bulk and low resistivity epitaxial) samples and one set of n sup + -p junctions have been irradiated with fast neutrons up to 8x10 sup 1 sup 3 cm sup - sup 2. I-V and C-V characteristics as well as Thermally Stimulated Currents (TSC) and Hall Effect (HE) analyses have been performed on the irradiated samples and diodes in view to determine the radiation-induced damage and the change in the electrical properties. A change in the effective carrier concentration and in the leakage current after irradiation similar to the one found for p sup + -n detectors has been observed in p-type diodes. An increase with the fluence of the resistivity and Hall coefficient was measured at room temperature both for the low and high resistivity sets. This evidence has been explained in terms of a two-level model taking into account a linear increase in concentration with the fluence of the main radiation-induced defects observed with TSC, probably related to divacancy and carbon-oxyge...

  4. Effect of electron excitation on radiation damage in fce metals

    Science.gov (United States)

    Iwase, A.; Iwata, T.

    1994-05-01

    Defect production, radiation annealing and defect recovery are studied in several fcc metals (Al, Cu, Ni, Ag and Pt) irradiated with low-energy (˜ 1 MeV) and high-energy (˜ 100 MeV) ions. Irradiation of the metals with strong electron-lattice interaction (Al, Ni and Pt) by ˜ 100 MeV ions causes an anomalous reduction, or even a complete disappearance of stage-I recovery. This experimental result shows that the energy transferred from excited electrons to lattice atoms through the electron-lattice interaction contributes to the annihilation of single interstitials. This effect is also observed in Ni as a large cross section for radiation annealing, and a decrease of the damage efficiency. On the other hand, in Cu and Ag thin foils, we find that lattice defects are produced not only through elastic interactions, but also through a process strongly associated with electron excitation. In the latter process, the defect production cross section is proportional to Se1.7 in Cu and Se1.5 in Ag. The nearly quadratic dependence of the cross section on Se suggests that the mutual Coulomb repulsion of ions positively charged by electron excitation causes the defect production.

  5. Result of radiation therapy of sino-nasal cancers using partial attenuation filter

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Hee; Kim, Ok Bae; Choi, Tae Jin [Keimyung University College of Medicine, Daegu (Korea, Republic of)

    2007-06-15

    This study was to evaluate the survival and pattern of failure after radiation therapy of sino-nasal cancer using partial attenuation filer and wedged beams and to help radiotherapy planning of sino-nasal cancer. Between February 1992 and March 2003, 17 patients with sino-nasal cancers underwent radiation therapy using partial attenuation filter at Dongsan Medical Center, Keimyung university. There were 9 male and 8 female patients. Patients' age ranged from 40 to 75 years (median 59 years). There were 10 patients of maxillary sinus cancer, 7 patients of nasal cancer. The histologic type was squamous cell carcinoma in 11, adenoid cystic carcinoma in 4 and olfactory neuroblastoma in 2. The distribution of clinical stage by the AJCC system was 3 for stage II, 7 for III and 6 for IV. The five patients were treated with radiation alone and 12 patients were treated with surgery and postoperative radiation therapy. The range of total radiation dose delivered to the primary tumor was from 44 to 76 Gy (median 60 Gy). The follow-up period ranged from 3 to 173 months with median of 78 months. The overall 2 year survival rate and disease free survival rate was 76.4%. The 5 year and 10 year survival rate were 76.4% and 45.6% and the 5 year and 10 year disease free survival rate was 70.6%. The 5 year disease free survival rate by treatment modality was 91.6% for postoperative radiation group and 20% for radiation alone group, statistical significance was found by treatment modality ({rho} = 0.006). There were no differences in survival by pathology and stage. There were local failure in 5 patients (29%) but no distant failure and no severe complication required surgical intervention. Radiation therapy of sino-nasal cancer using partial attenuation filter was safe and effective. Combined modality with conservative surgery and radiation therapy was more advisable to achieve loco-regional control in sino-nasal cancer. Also we considered high precision radiation therapy with

  6. Does Statin Modulate Oxidative Damage Induced by ionizing Radiation in Mouse?

    International Nuclear Information System (INIS)

    HMG-CoA (3-Hydroxy-3-methylglutaryl coenzyme-A) reductase inhibitors commonly referred to as the statins family. The aim of the present work was to evaluate the role of statins on oxidative stress, endothelial function, inflammatory response and bleeding time in gamma irradiated mice. Irradiated mice received 6 Gy y-rays, instilled as 2 fractions (I Gy each/week) for 3 weeks. Treated irradiated animals received by gavage atorvastatin; a synthetic form of statins (10 mg/kg body wt, 3-times/week for 3 weeks) within the same schedule of irradiation. In irradiated mice group, the results revealed significant increases of thiobarbituric acid reactive substances (TBARS), protein carbonyl values, creatine phosphokinase (CPK) activity, C-reactive protein (CRP) level as well as bleeding time. While, there was significant decreases of reduced glutathione (GSH) and nitric oxide (NO) levels, and superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) activities. In treated-irradiated mice group, atorvastatin application has significantly improved the radiation-induced changes in all these tested parameters. It could be concluded that, atorvastatin may be applied to minimize radiation damage and attenuate the side effects of radiotherapy. These results observed in mice need to be confirmed in other experimental models, but could become a part of the rationale of further randomised clinical trails in patients treated by radiotherapy

  7. Influence of magnetite and boron carbide on radiation attenuation of cement-fiber/composite

    International Nuclear Information System (INIS)

    Trial was made to create composites from agriculture fibers, which have good mechanical, physical and radiation attenuation properties for different applications. Fast neutron and gamma ray spectra, as well as, slow neutron fluxes behind samples of cement-fiber (CF) (ρ=2.095 g cm-3) and cement-fiber-magnetite (CFM) (ρ=2.858 g cm-3)/composites have been investigated. Neutron and gamma spectra have been measured using a collimated reactor beam and neutron- gamma spectrometer with stilbene scintillator. A pulse shape discrimination technique based on zero cross over method was used to discriminate between neutron and gamma ray pulses. While, slow neutron fluxes have been measured using a collimated reactor beam and BF3 counter. Results were used to achieve removal cross sections (ΣR,meas.), total attenuation coefficients (μ) and macroscopic cross sections (Σ) of fast neutrons, gamma rays and slow neutrons respectively from the attenuation relations. Also, removal cross sections (ΣR,cal.) and total mass attenuation coefficients (μ/ρ) of fast neutrons and gamma rays have been calculated using the composites elemental composition and XCOM code respectively. Measured and calculated results were compared and a reasonable agreement was found

  8. Analysis of radiation-induced cell damages as inflammation and study on nutritional factors to repress and relieve the damages

    International Nuclear Information System (INIS)

    Radiation induced cell damages were analyzed from an aspect of an inflammation along with DNA damages to progress a molecular-immunological analysis of the mechanism for spreading of such cell damages. Human fibroblast cell line, NB1RBG at confluent stage was exposed to X-ray at 40 Gy and the spreading of radiation-induced damages was monitored. It is well known that cytokines are generally produced by the cells in immune system, but those are also expressed in the cells of non-immune system such as HeLa cell, fibroblast cell, etc. Therefore, cytokine expression in NB1RBG cells exposed to radiation was investigated by RT-PCR method. However, it was found that the expression of IL-1βinduced by radiation irradiation became maximum 8 hours after the irradiation and any expression of IL-6, IL-10 or TNF-α was not induced by X-ray radiation. Meanwhile, expressions of IL-1ββ and TNF-α of various inflammatory cytokines were inducible by UV exposure. These results suggested that the spreading factor might be IL-1β or TNF-α for UV-induced damages and IL-1β for X-ray induced ones. (M.N.)

  9. Case report of the radiation damage to the developing teeth

    International Nuclear Information System (INIS)

    In the treatment of malignant diseases about the head and neck, radium, x-rays and other radioactive materials are used as therapeutic agents. When irradiation is heavy, deleterious effects may be seen later in jaws, the teeh, or in both teeth and jaws. Young patients with undeveloped and developing teeth, despite lower dosages, are more subject to radiation damage to the teeth. After heavy exposure, grossly stunted teeth may appear. The crown is sometimes smoller than normal and deformed, and the root may be grossly underdeveloped. Sometimes the crown is formed normally but the roots are absent. This case is presented in which the mandibular jaw was irradiated at 3 years old and it was possible to examine some of the abnormal teeth in detail by using clinical, radiographic, and histologic technicques. The patient was first seen on June 21, 1982, at the age of 6 years old and one month. His medical history revealed that when he was 3 years old a malignant fibrous histiocytoma of the left mandibula. Radiation therapy (Linac) began at 3 years old and three months and extended over a period of one month. The total dose was 4750 rads. The crown of other teeth were formed normally but when the patient was 7 years old, the upper left lateral incisor was appeared to have short clinical crown. Radiographs revealed that roots of lower incisors were short and roots of molars were absent. The extracted lower molar was cut undecalcified to produce planoparallel section. The section showed that the dysplastic dentin was formed and it was continuous with the alveolar bone at the base of the tooth. (author)

  10. Radiation damage studies related to nuclear waste forms

    International Nuclear Information System (INIS)

    Much of the previously reported work on alpha radiation effects on crystalline phases of importance to nuclear waste forms has been derived from radiation effects studies of composite waste forms. In the present work, two single-phase crystalline materials, Gd2Ti2O7 (pyrochlore) and CaZrTi2O7 (zirconolite), of relative importance to current waste forms were studied independently by doping with 244Cm at the 3 wt % level. Changes in the crystalline structure measured by x-ray diffraction as a function of dose show that damage ingrowth follows an expected exponential relationship of the form ΔV/V0 = A[1-exp(-BD)]. In both cases, the materials became x-ray amorphous before the estimated saturation value was reached. The predicted magnitudes of the unit cell volume changes at saturation are 5.4% and 3.5%, respectively, for Gd2Ti2O7 and CaZrTi2O7. The later material exhibited anisotropic behavior in which the expansion of the monoclinic cell in the c0 direction was over five times that of the a0 direction. The effects of transmutations on the properties of high-level waste solids have not been studied until now because of the long half-lives of the important fission products. This problem was circumvented in the present study by preparing materials containing natural cesium and then irradiating them with neutrons to produce 134Cs, which has only a 2y half-life. The properties monitored at about one year intervals following irradiation have been density, leach rate and microstructure. A small amount of x-ray diffraction work has also been done. Small changes in density and leach rate have been observed for some of the materials, but they were not large enough to be of any consequence for the final disposal of high level wastes

  11. Radiation damage to Fpg protein complex with DNA oligomer containing abasic site analog

    Czech Academy of Sciences Publication Activity Database

    Běgusová, Marie

    Edmonton, Alberta: University of Alberta, Cross Cancer Institute, 2004. P4. [International Workshop on Radiation Damage to DNA /8./. 25.05.2004-30.05.2004, Banff, Alberta] R&D Projects: GA AV ČR IAA1048103 Institutional research plan: CEZ:AV0Z1048901 Keywords : Fpg protein * abasic site analog * radiation damage * DNA-protein complex Subject RIV: BO - Biophysics

  12. CHO cell death, strand break damage, and repair due to combination radiation and hyperthermia

    International Nuclear Information System (INIS)

    Previous reports have suggested a relationship between the hyperthermia induced changes in nucleoprotein and the hyperthermic enhancement of radiation sensitivity. In this investigation, the level of initial strand break damage, DNA strand rejoining kinetics, DNA/protein ratios, and residual DNA damage were measured following combined hyperthermia and radiation treatments in an attempt to further understand these relationships

  13. Annealing induced recrystallization of radiation damaged titanite and allanite

    International Nuclear Information System (INIS)

    Minerals can become metamict over geological time periods as a result of structural damage induced by α-decay events resulting from incorporated radiogenic elements. The structural state and the thermally induced recrystallization behavior of metamict titanite were studied by Raman spectroscopy, synchrotron single-crystal X-ray diffraction, nanoindentation and complementary high-resolution transmission electron microscopy. The results of the Raman spectroscopic measurements show that Raman scattering collected from metamict titanite is still anisotropic, which is typical of single crystals and indicates oriented, basically coherent structural elements. The observed Raman scattering dependence on the sample orientation is on the other hand much more pronounced for heavily metamict than for weakly metamict titanite samples. Radiation-induced anisotropic effects are related to the specific atomic arrangements in the structure of metamict titanite. This leads to the opportunity to study separately the structural transformations of the crystalline and amorphous fractions in metamict titanite by using Raman spectroscopy. That is possible because the Raman modes in the spectra collected from a plane nearly perpendicular to the chains of corner-sharing TiO6 octahedra arise predominantly from phonon modes in crystalline nanoregions with radiation-induced defects. In contrast to the contribution of atomic vibrations in radiation-induced amorphous nanoregions, which is better pronounced in spectra collected from a plane containing TiO6 chains. The results show that radiation-induced periodic faults in the crystalline matrix are related to the disturbance of SiO4-TiO6-SiO4-TiO6 rings comprising TiO6 octahedra from different chains. The radiation-induced amorphization by contrast is related to the partial change of Ti coordination from octahedral to pyramidal and/or tetrahedral, which leads to a rising Ti-O bond strength. This in turn violates the Ti-O-Ti intrachain linkages

  14. Radiation damage in stainless steel under varying temperature neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Naoaki [Kyushu Univ., Kasuga, Fukuoka (Japan). Research Inst. for Applied Mechanics

    1998-03-01

    Microstructural evolution of model alloys of 316SS was examined by neutron irradiation at JMTR under cyclic temperature varying condition. In the case of Fe-16Cr-17Ni, formation of interstitial loops and voids are strongly suppressed by varying the temperature from 473K to 673K. By adding Ti as miner element (0.25wt%), however, abnormal accumulation of vacancies (void swelling of 11%dpa at 0.1dpa) was observed. Theoretical analysis standing on the rate theory of defect clustering and simulation irradiation experiments with heavy ions indicates that the vacancy-rich condition which appears temporally during and after changing the temperature from low to high brings these results. It was also shown that only 1 dpa pre-irradiation at low temperature changes swelling behavior at high temperature above several 10 dpa. The understanding of non-steady-state defect processes under temperature varying irradiation is very important to estimate the radiation damage under fusion environment where short-term and long-term temperature variation is expected. (author)

  15. Radiation damage studies on CrO42- doped alums

    International Nuclear Information System (INIS)

    Radiation damage studies have been carried out on undoped and CrO42- doped potassium and ammonium alums. The optical absorption bands observed around 27100 and 36500 cm-1 before irradiation have been attributed to the transitions t1 → e and t1 → t2, on the basis of Ball-hausen and Liehr scheme. On prolonged X-irradiation, these bands disappear in both the alums and three new bands seem to grow in ammonium alum while only two new bands could be seen in potassium alum. EPR studies at RT reveal that there are two lines at g = 2.004 and g = 2.010 in ammonium alum and only one line at g = 2.004 in potassium alum. Besides these two nearly isotropic lines, there is a set of lines around g = 1.95 in both the alums. Correlating the optical and EPR studies it is concluded that SO3- and O3- centres have formed on X-irradiation in ammonium alum while only SO3- seems to have formed in potassium alum. The most important feature is the formation of a new paramagnetic radical on X-irradiation, identified as CrO43-,whose g values is around 1.95 in both the alums. (auth.)

  16. Potential vascular damage from radiation in the space environment

    Science.gov (United States)

    Griem, M. L.; Robotewskyj, A.; Nagel, R. H.

    1994-10-01

    Cultured endothelial cells of blood vessels have a Do of 2 Gy for X-rays. A dose of 0.5 Gy of X-rays has an acute effect on vessel diameter. The vessels may show other acute effects such as change in permeability including a change in the blood brain barrier. Changes occurring from late effects of chronic exposure in vascular architecture include telangiectasia and decrease in vascular density. Changes in the perivascular connective tissue particularly collagen may play a role in these changes. After charged particle exposure of 15 and 30 Gy, radiation changes in the blood brain barrier and vascular changes are noted in the nervous system. These long term changes are recorded by PET, MRI, and CT imaging. Chronic exposure to alpha particles causes vascular damage in compact bone resulting in bone infarcts. Using tandem scanning confocal microscopy in-situ imaging of the capillaries and collagen of the papillary dermis provides a non-invasive method of serial recording of changes in irradiated microvasculature.

  17. Clustered DNA damages induced in human hematopoietic cells by low doses of ionizing radiation

    International Nuclear Information System (INIS)

    Ionizing radiation induces clusters of DNA damages-oxidized bases, abasic sites and strand breaks-on opposing strands within a few helical turns. Such damages have been postulated to be difficult to repair, as are double strand breaks (one type of cluster).We have shown that low doses of low and high linear energy transfer (LET) radiation induce such damage clusters in human cells. In human cells, double strand breaks (DSB) are about 30% of the total of complex damages, and the levels of DSBs and oxidized pyrimidine clusters are similar. The dose responsesfor cluster induction in cells can be described by a linear relationship, implying that even low doses of ionizing radiation can produce clustered damages. Studies are in progress to determine whether clusters can be produced by mechanisms other than ionizing radiation, as well as the levels of various cluster types formed by low and high LET radiation. (author)

  18. Radiation damage in natural and synthetic halite. Progress report January 1992 - February 1993

    International Nuclear Information System (INIS)

    This report complements the information presented in the report of December 1992 regarding the research performed at the ECN on radiation damage in salt. It consists of two parts. The first part regards the amount of stored energy which can be developed by gamma-irradiation on different types of halite and considers both the effect of low dose rates in developing radiation damage, and the possible saturation level of radiation damage in natural halite. The second part presents a model to simulate radiation damage development which incorporates some extensions in the Jain-Lidiard model. Due to malfunction of the Small Angle Neutron Scattering installation, neither the previously reported results nor the newly obtained can be trusted and therefore are not reported here. These results regard the shape, size and size distribution of radiation damage defects. (orig.)

  19. Microscopic model for chemical etchability along radiation damage paths in solids

    Institute of Scientific and Technical Information of China (English)

    Mukhtar Ahmed RANA

    2008-01-01

    It would be very interesting to develop a picture about removal of atoms from the radiation damaged paths or latent nuclear tracks and undamaged bulk material in track detectors. Here, theory of chemical etching is described briefly and a new model for chemical etching along radiation damaged paths in solids is developed based on basic scientific facts and valid assumptions. Dependence of chemical etching on radiation damage intensity and etching conditions is discussed. A new parameter for etching along radiation damaged paths is introduced, which is useful for investigation of relationship between chemical etchability and radiation damage in a solid. Results and discussion presented here are also useful for further development of nuclear waste immobilization.

  20. Loss of Matrix Metalloproteinase-13 Attenuates Murine Radiation-Induced Pulmonary Fibrosis

    International Nuclear Information System (INIS)

    Purpose: Pulmonary fibrosis is a disorder of the lungs with limited treatment options. Matrix metalloproteinases (MMPs) constitute a family of proteases that degrade extracellular matrix with roles in fibrosis. Here we studied the role of MMP13 in a radiation-induced lung fibrosis model using a MMP13 knockout mouse. Methods and Materials: We investigated the role of MMP13 in lung fibrosis by investigating the effects of MMP13 deficiency in C57Bl/6 mice after 20-Gy thoracic irradiation (6-MV Linac). The morphologic results in histology were correlated with qualitative and quantitative results of volume computed tomography (VCT), magnetic resonance imaging (MRI), and clinical outcome. Results: We found that MMP13 deficient mice developed less pulmonary fibrosis than their wildtype counterparts, showed attenuated acute pulmonary inflammation (days after irradiation), and a reduction of inflammation during the later fibrogenic phase (5-6 months after irradiation). The reduced fibrosis in MMP13 deficient mice was evident in histology with reduced thickening of alveolar septi and reduced remodeling of the lung architecture in good correlation with reduced features of lung fibrosis in qualitative and quantitative VCT and MRI studies. The partial resistance of MMP13-deficient mice to fibrosis was associated with a tendency towards a prolonged mouse survival. Conclusions: Our data indicate that MMP13 has a role in the development of radiation-induced pulmonary fibrosis. Further, our findings suggest that MMP13 constitutes a potential drug target to attenuate radiation-induced lung fibrosis.

  1. Physical Properties of P.V.C. Attenuated Network Copolymers Produced by Ionizing Radiation

    International Nuclear Information System (INIS)

    The cross-linking of polyvinyl chloride with ionizing radiation poses special problems. Due to rather unfavourable cross-linking and dislinking parameters for this polymer, the radiation doses necessary for high cross-link densities are uneconomicall y large and discolouration and dehydrohalogenatio n are simultaneously produced. These difficulties have been overcome by the incorporation into the P. V. C., prior to irradiation, of diallyl and triallyl esters. Heavily cross-linked products are thereby obtained with relatively low doses of ionizing radiation. Examination of the physical properties of the products suggests that these are not simply graft copolymers, which term normally implies the presence of long branch chains, but are polymer attenuated allyl networks. In these materials, the desirable properties of the parent polymer and of the allyl network are combined. The tensile strength, modulus and elongation of the attenuated network copolymers are presented and discussed as a function of temperature and of the concentration and functionality of the allyl ester. Reference is also made to the swelling and chemical resistance of the products. (author)

  2. Radiation-induced attenuation self-compensating effect in super-fluorescent fiber source

    International Nuclear Information System (INIS)

    The compact super-fluorescent fiber source (SFS) output spectra variations at different pump currents and under different dose of gamma-ray radiation were measured and compared respectively. The radiation-induced attenuation (RIA) self-compensating effect in SFS based on photo-bleaching was found and the general mathematic model of SFS output spectra variations was made. The radiation-induced background attenuation (RIBA) at the pump wavelength was identified to be the main cause of the total output power and spectra variations and the variations can then be compensated by active control of the pump power to enhance the self-compensating effect. With closed-loop feedback control of pump current, double-pass backward (DPB) configuration and spectrum re-shaping technology, an SFS prototype was made and tested. The mean-wavelength stability of about 87.4 ppm and output power instability of less than 5% were achieved under up to 200 krad (Si) gamma-ray irradiation. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  3. Rapamycin-mediated mTOR inhibition attenuates survivin and sensitizes glioblastoma cells to radiation therapy

    Institute of Scientific and Technical Information of China (English)

    Arunkumar Anandharaj; Senthilkumar Cinghu; Woo-Yoon Park

    2011-01-01

    Survivin, an antiapoptotic protein, is elevated in most malignancies and attributes to radiation resistance in tumors including glioblastoma multiforme. The downregulation of survivin could sensitize glioblastoma ceils to radiation therapy. In this study, we investigated the effect of rapamycin, an inhibitor of mammalian target of rapamycin (mTOR), in attenuating survivin and enhancing the therapeutic efficacy for glioblastoma cells, and elucidated the underlying mechanisms. Here we tested various concentrations of rapamycin (1-8 nM) in combination with radiation dose 4 Gy. Rapamycin effectively modulated the protein kinase B (Akt)/mTOR pathway by inhibiting the phosphorylation of Akt and mTOR proteins, and this inhibition was further enhanced by radiation. The expression level of survivin was decreased in rapamycin pre-treatment glioblastoma ceils followed by radiation; meanwhile, the phosphorylation of H2A histone family member X (H2AX) at serine-139 (γ-H2AX) was increased, p21 protein was also induce on radiation with rapamycin pre-treatment, which enhanced G1 arrest and the accumulation of cells at G0/subG1 phase. Furthermore, the clonogenic cell survival assay revealed a significant dose-dependent decrease in the surviving fraction for all three cell lines pre-treated with rapamycin. Our studies demonstrated that targeting survivin may be an effective approach for radiosensitization of malignant glioblastoma.

  4. Exendin-4 attenuates brain death-induced liver damage in the rat.

    Science.gov (United States)

    Carlessi, Rodrigo; Lemos, Natalia E; Dias, Ana L; Brondani, Leticia A; Oliveira, Jarbas R; Bauer, Andrea C; Leitão, Cristiane B; Crispim, Daisy

    2015-11-01

    The majority of liver grafts destined for transplantation originate from brain dead donors. However, significantly better posttransplantation outcomes are achieved when organs from living donors are used, suggesting that brain death (BD) causes irreversible damage to the liver tissue. Recently, glucagon-like peptide-1 (GLP1) analogues were shown to possess interesting hepatic protection effects in different liver disease models. We hypothesized that donor treatment with the GLP1 analogue exendin-4 (Ex-4) could alleviate BD-induced liver damage. A rat model of BD was employed in order to estimate BD-induced liver damage and Ex-4's potential protective effects. Liver damage was assessed by biochemical determination of circulating hepatic markers. Apoptosis in the hepatic tissue was assessed by immunoblot and immunohistochemistry using an antibody that only recognizes the active form of caspase-3. Gene expression changes in inflammation and stress response genes were monitored by quantitative real-time polymerase chain reaction. Here, we show that Ex-4 administration to the brain dead liver donors significantly reduces levels of circulating aspartate aminotransferase and lactate dehydrogenase. This was accompanied by a remarkable reduction in hepatocyte apoptosis. In this model, BD caused up-regulation of tumor necrosis factor and stress-related genes, confirming previous findings in clinical and animal studies. In conclusion, treatment of brain dead rats with Ex-4 reduced BD-induced liver damage. Further investigation is needed to determine the molecular basis of the observed liver protection. After testing in a randomized clinical trial, the inclusion of GLP1 analogues in organ donor management might help to improve organ quality, maximize organ donation, and possibly increase liver transplantation success rates. PMID:26334443

  5. Damage evolution law of coal-rock under uniaxial compression based on the electromagnetic radiation characteristics

    Institute of Scientific and Technical Information of China (English)

    Jin Peijian; Wang Enyuan; Liu Xiaofei; Huang Ning; Wang Siheng

    2013-01-01

    Based on electromagnetic radiation characteristics,the present research studied the damage evolution of rock under uniaxial compression.Besides,this research built the coal-rock damage evolution model considered residual strength.The applicability and accuracy of the model were verified through experiments.The results show that coal-rock damage evolution consists of four periods.The first period is from the beginning of compression to nearly 20% of the stress peak value,during which the damage variable changes stably about 0.1,and accordingly a few of electromagnetic radiation signals emerge.The second period is from about 20% to 70% of the stress peak value.The damage has stable development,and the parameter of electromagnetic radiation characteristics turns larger continuously with the increase of stress.The third period is when the damage has accelerated development,the coal-rock was broken which result from sharp increasing of the damage variable,meanwhile a great quantity of electromagnetic radiation signals emerge.The fourth period is after the coal-rock fracture,during which the damage variable corresponding to the parameter of electromagnetic radiation characteristics has a stable development.This research has great academic and realistic significance for further studies the electromagnetic radiation characteristics of coal-rock under loading and damage and the forecasting of coal-rock dynamic disasters.

  6. Repair of radiation damages to haemopoietic stem cells of mouse embryonal liver: kinetic aspects

    International Nuclear Information System (INIS)

    The method of fractionated irradiation was used to study kinetic aspects of repair of sublethal radiation damages in precursor cells from mouse embryonal liver that form in vivo colonies on 8th and 11th days. It was shown that 11-day CFUs had a lesser ability to repair sublethal radiation damages than 8-day ones at different time-intervals between radiation fractions (from 2 to 6 h). These two CFUs subpopulations differed also in the repair kinetics

  7. Buckwheat Honey Attenuates Carbon Tetrachloride-Induced Liver and DNA Damage in Mice

    OpenAIRE

    Ni Cheng; Liming Wu; Jianbin Zheng; Wei Cao

    2015-01-01

    Buckwheat honey, which is widely consumed in China, has a characteristic dark color. The objective of this study was to investigate the protective effects of buckwheat honey on liver and DNA damage induced by carbon tetrachloride in mice. The results revealed that buckwheat honey had high total phenolic content, and rutin, hesperetin, and p-coumaric acid were the main phenolic compounds present. Buckwheat honey possesses super DPPH radical scavenging activity and strong ferric reducing antiox...

  8. Buckwheat Honey Attenuates Carbon Tetrachloride-Induced Liver and DNA Damage in Mice

    Directory of Open Access Journals (Sweden)

    Ni Cheng

    2015-01-01

    Full Text Available Buckwheat honey, which is widely consumed in China, has a characteristic dark color. The objective of this study was to investigate the protective effects of buckwheat honey on liver and DNA damage induced by carbon tetrachloride in mice. The results revealed that buckwheat honey had high total phenolic content, and rutin, hesperetin, and p-coumaric acid were the main phenolic compounds present. Buckwheat honey possesses super DPPH radical scavenging activity and strong ferric reducing antioxidant power. Administration of buckwheat honey for 10 weeks significantly inhibited serum lipoprotein oxidation and increased serum oxygen radical absorbance capacity. Moreover, buckwheat honey significantly inhibited aspartate aminotransferase and alanine aminotransferase activities, which are enhanced by carbon tetrachloride. Hepatic malondialdehyde decreased and hepatic antioxidant enzymes (superoxide dismutase and glutathione peroxidase increased in the presence of buckwheat honey. In a comet assay, lymphocyte DNA damage induced by carbon tetrachloride was significantly inhibited by buckwheat honey. Therefore, buckwheat honey has a hepatoprotective effect and inhibits DNA damage, activities that are primarily attributable to its high antioxidant capacity.

  9. Treatment with glial derived neurotropic factor (GDNF attenuates oxidative damages of spinal

    Directory of Open Access Journals (Sweden)

    Tao Li

    2016-05-01

    Full Text Available Spinal cord injury (SCI is a serious and debilitating issue being suffered by wide population worldwide. Extensive treatment approaches have been tested and being verified for their efficacy. Owing to the nature of central nervous system (CNS, the resident stem cells would be triggered in response to any sort of trauma with nerve factors as their communication signals. Apart from physical injuries, damages due to oxidative stress also need to be addressed while CNS repair mechanism takes place. This study looks at the potential of glial derived nerve factor (GDNF in addressing the SCI in regard to oxidative damages. A total of 60 Wistar rats were clustered into five groups and GDNF at various concentrations was tested in each group. Assessments in terms of oxidative stress parameters were noted and analyzed accordingly. It was noted that GDNF had reduced oxidative damages and increased the levels of anti-oxidants in dose-dependent manner (p < 0.05. Though treatment with 10 mg/mL and 20 mg/mL showed significant changes as compared to control group, these treatment modalities remained insignificant among each other. In conclusion, we demonstrated that GDNF exerted a neuro-protective effect on CNS by inducing anti-oxidants and reducing the levels of oxidative stress in SCI induced rat models.

  10. Research progress in radiation detectors, pattern recognition programs, and radiation damage determination in DNA

    Science.gov (United States)

    Baily, N. A.

    1973-01-01

    The radiological implications of statistical variations in energy deposition by ionizing radiation were investigated in the conduct of the following experiments: (1) study of the production of secondary particles generated by the passage of the primary radiation through bone and muscle; (2) the study of the ratio of nonreparable to reparable damage in DNA as a function of different energy deposition patterns generated by X rays versus heavy fast charged particles; (3) the use of electronic radiography systems for direct fluoroscopic tomography and for the synthesis of multiple planes and; (4) the determination of the characteristics of systems response to split fields having different contrast levels, and of minimum detectable contrast levels between the halves under realistic clinical situations.

  11. Development of radiation biological dosimetry and treatment of radiation-induced damaged tissue

    International Nuclear Information System (INIS)

    Util now, only a few methods have been developed for radiation biological dosimetry such as conventional chromosome aberration and micronucleus in peripheral blood cell. However, because these methods not only can be estimated by the expert, but also have a little limitation due to need high technique and many times in the case of radiation accident, it is very difficult to evaluate the absorbed dose of victims. Therefore, we should develop effective, easy, simple and rapid biodosimetry and its guideline(triage) to be able to be treated the victims as fast as possible. We established the apoptotic fragment assay, PCC, comet assay, and micronucleus assay which was the significant relationship between dose and cell damages to evaluate the irradiated dose as correct and rapid as possible using lymphocytes and crypt cells, and compared with chromosome dosimetry and micronucleus assay

  12. Development of radiation biological dosimetry and treatment of radiation-induced damaged tissue

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Chul Koo; Kim, Tae Hwan; Lee, Yun Sil [and others

    2000-04-01

    Util now, only a few methods have been developed for radiation biological dosimetry such as conventional chromosome aberration and micronucleus in peripheral blood cell. However, because these methods not only can be estimated by the expert, but also have a little limitation due to need high technique and many times in the case of radiation accident, it is very difficult to evaluate the absorbed dose of victims. Therefore, we should develop effective, easy, simple and rapid biodosimetry and its guideline(triage) to be able to be treated the victims as fast as possible. We established the apoptotic fragment assay, PCC, comet assay, and micronucleus assay which was the significant relationship between dose and cell damages to evaluate the irradiated dose as correct and rapid as possible using lymphocytes and crypt cells, and compared with chromosome dosimetry and micronucleus assay.

  13. Characterization of barite and crystal glass as attenuators in X-ray and gamma radiation shieldings

    International Nuclear Information System (INIS)

    Aiming to determine the barium sulphate (BaSO4) ore and crystal glass attenuation features, both utilized as shieldings against ionizing X and gamma radiations in radiographic installations, a study of attenuation using barite plaster and barite concrete was carried out, which are used, respectively, on wall coverings and in block buildings. The crystal glass is utilized in screens and in windows. To do so, ten plates of barite plaster and three of barite concrete with 900 cm2 and with an average thickness ranging from 1 to 5 cm, and three plates of crystal glass with 323 cm2 and with thicknesses of 1, 2 and 4 cm were analyzed. The samples were irradiated with X-rays with potentials of 60, 80, 110 and 150 kilovolts, and also with 60Co gamma rays. Curves of attenuation were obtained for barite plaster and barite concrete (mGy/mA.min) and (mGy/h), both at 1 meter, as a function of thickness and curve of transmission through barite plaster and barite concrete as a function of the thickness. The equivalent thicknesses of half and tenth value layers for barite plaster, barite concrete and crystal glass for all X-Ray energies were also determined. (author)

  14. Grappling with problems in analytical science for radiation damage in DNA

    International Nuclear Information System (INIS)

    I have been considering how to clarify chemical difference in DNA damage spectrum among radiation qualities. In order to confront the problem, it should be necessary to develop new-conceptual analytical methods for damaged DNA by ionizing radiation. In this report, following to the explanation of overall background of upstream of radiation biology, brief history of the analytical chemistry with problems, a few analytical trials to discover characteristics of radiation qualities are demonstrated. The present efforts against the problems are discovering difference in strand-break termini between high- and low-LET radiation. (author)

  15. Radiation damage resistance and interface stability of copper–graphene nanolayered composite

    International Nuclear Information System (INIS)

    The radiation damage resistance and interface stability of copper–graphene nanolayered composite are studied by atomistic simulations. Results show that the number of surviving point defects in bulk region is always less than that of pure copper at 100 K, when the range of initial distance d between a primary knock-on atom (PKA) with 3 keV and copper–graphene interface is less than 4 nm. The above phenomenon also occurs at 300, 500, and 700 K when d is ∼15.4 Å, thereby implying that the composite resulting from copper–graphene interfaces exhibits excellent ability to resist radiation damage. A higher PKA energy corresponds to worse radiation damage of graphene in the composite. The damage may impair interface stability and eventually weaken the radiation damage resistance of the composite

  16. Efficacy of Carnosine in Modulating Radiation-Induced Oxidative Damage and Neurotransmitter Alterations in Rat Brain

    International Nuclear Information System (INIS)

    The present study was designed to investigate the role of carnosine (β-alanyl-L-histidine) in alleviating oxidative damage and alteration of neurotransmitters in the brain of rats exposed to gamma radiation. Male albino rats were whole body exposed to a single dose of γ- rays (5 Gy). Carnosine (50 mg/Kg/day) was administered via gavages as follows: a) during 28 successive days, b) during 14 successive days before whole body gamma irradiation and administered distilled water for 14 days after irradiation, c) during 14 successive days before whole body gamma irradiation and during 14 days after irradiation with carnosine. The animals were sacrificed at 1, 7 and 14 days post irradiation. (3 hours after the last dose of carnosine). The results revealed that exposure to γ- rays, (5 Gy(, resulted in significant increases of the levels of thiobarbituric acid reactive substances (TBARS), protein carbonyls (CO), and advanced oxidation protein products (AOPP), associated with significant decreases of superoxide dismutase (SOD) and catalase (CAT) activities, and glutathione (GSH) content which indicate oxidative stress. Gamma rays also, induced significant decrease of the serotonin (5-HT), dopamine (DA), norepinephrine (NE) and epinephrine (EPI) contents as well as significant increase of 5-hydroxy-indole-acetic-acid (5-HIAA) level and monoamine oxidase (MAO) activity which indicated alterations in the metabolism of monoamines. Carnosine has significantly attenuated oxidative stress, and monoamine alterations in the cerebral hemispheres of irradiated rats. Carnosine might preserve the integrity of brain functions.

  17. Influence of magnetite, ilmenite and boron carbide on radiation attenuation of polyester composites

    International Nuclear Information System (INIS)

    This work is concerned with studying polyester/ magnetite CUP/Mag (ρ=2.75 g cm−3) and polyester/ ilmenite CUP/Ilm (ρ=2.7 g cm−3) composites for shielding of medical facilities, laboratory hot cells and for various purposes. Mechanical and physical properties such as compressive, flexural and impact strengths, as well as, a.c. electrical conductivity, specific heat, water absorption and porosity have been performed to evaluate the composite capabilities for radiation shielding. A collimated beam from fission 252Cf (100 µg) neutron source and neutron-gamma spectrometer with stilbene scintillator based on the zero cross over method and pulse shape discrimination (P.S.D.) technique have been used to measure neutron and gamma ray spectra. Fluxes of thermal neutrons have been measured using the BF3 detector and thermal neutron detection system. The attenuation parameters, namely macroscopic effective removal cross-section ΣR, total attenuation coefficient µ and macroscopic cross-section Σ of fast neutrons, gamma rays and thermal neutrons respectively have been evaluated. Theoretical calculations using MCNP–4C2 code was used to calculate ΣR,μ and Σ. Also, MERCSF-N program was used to calculate macroscopic effective removal cross-section ΣR. Measured and calculated results were compared and reasonable agreement was found. - Highlights: • Loaded polyester composites were investigated for radiation shielding. • Some mechanical and physical properties were examined. • Experimental and theoretical attenuation parameters were studied. • Experimental and theoretical (MCNP-4C2) results were in good agreement

  18. Aminoguanidine Alleviates Radiation-Induced Small-Bowel Damage Through Its Antioxidant Effect

    International Nuclear Information System (INIS)

    Purpose: To evaluate the effect and its mechanism of aminoguanidine (AG) on small-bowel protection after whole-abdominal irradiation (WAI) in rats. Methods and Materials: Male Sprague-Dawley rats (300-400 g) subjected to 12 Gy WAI were used for the study. Aminoguanidine at a dose of 50-800 mg/kg was administered by the gavage route 2 h before WAI. Mucosal damage of small bowel was evaluated by the grade of diarrhea and crypt survival; oxidative stress was determined by the level of 8-hydroxy 2'-deoxyguanosine (8-OHdG) with immunohistochemistry (IHC). Nitrosative stress was evaluated by the expression of inducible nitric oxide synthase (iNOS) and 3-nitrotyrosine (3-NT) with IHC, and systemic and portal vein NOx (nitrite + nitrate) levels were measured and compared with and without AG treatment after WAI. Results: Aminoguanidine showed a dose-dependent effect against WAI-induced diarrhea. Aminoguanidine at a dose of 400 mg/kg had the best protective effect, from 92% to 17% (p = 0.002). Aminoguanidine increased crypt survival from 23% to 46% (p = 0.003). It also significantly attenuated 8-OHdG expression but not 3-NT and iNOS expression at both 4 and 8 h after 12-Gy WAI. Aminoguanidine did not alter the portal vein NOx levels 4 and 8 h after 12-Gy WAI. Conclusion: Aminoguanidine has a radioprotective effect against radiation-induced small-bowel damage due to its antioxidant effect but not inhibition of nitric oxide production. Dietary AG may have a potentially protective effect on the small intestine of patients subjected to pelvic and abdominal radiotherapies.

  19. Flavonoids can protect maize DNA from the induction of ultraviolet radiation damage

    International Nuclear Information System (INIS)

    Diverse flavonoid compounds are widely distributed in angiosperm families. Flavonoids absorb radiation in the ultraviolet (UV) region of the spectrum, and it has been proposed that these compounds function as UV filters. We demonstrate that the DNA in Zea mays plants that contain flavonoids (primarily anthocyanins) is protected from the induction of damage caused by UV radiation relative to the DNA in plants that are genetically deficient in these compounds. DNA damage was measured with a sensitive and simple assay using individual monoclonal antibodies, one specific for cyclobutane pyrimidine dimer damage and the other specific for pyrimidine(6,4)pyrimidone damage. (author)

  20. Maltol, a Food Flavoring Agent, Attenuates Acute Alcohol-Induced Oxidative Damage in Mice

    Directory of Open Access Journals (Sweden)

    Ye Han

    2015-01-01

    Full Text Available The purpose of this study was to evaluate the hepatoprotective effect of maltol, a food-flavoring agent, on alcohol-induced acute oxidative damage in mice. Maltol used in this study was isolated from red ginseng (Panax ginseng C.A Meyer and analyzed by high performance liquid chromatography (HPLC and mass spectrometry. For hepatoprotective activity in vivo, pretreatment with maltol (12.5, 25 and 50 mg/kg; 15 days drastically prevented the elevated activities of aspartate transaminase (AST, alanine transaminase (ALT, alkaline phosphatase (ALP and triglyceride (TG in serum and the levels of malondialdehyde (MDA, tumor necrosis factor-α (TNF-α, interleukin-1β (IL-1β in liver tissue (p < 0.05. Meanwhile, the levels of hepatic antioxidant, such as catalase (CAT, superoxide dismutase (SOD, glutathione peroxidase (GSH-Px were elevated by maltol pretreatment, compared to the alcohol group (p < 0.05. Histopathological examination revealed that maltol pretreatment significantly inhibited alcohol-induced hepatocyte apoptosis and fatty degeneration. Interestingly, pretreatment of maltol effectively relieved alcohol-induced oxidative damage in a dose-dependent manner. Maltol appeared to possess promising anti-oxidative and anti-inflammatory capacities. It was suggested that the hepatoprotective effect exhibited by maltol on alcohol-induced liver oxidative injury may be due to its potent antioxidant properties.

  1. Radiation-Induced Liver Damage: Correlation of Histopathology with Hepatobiliary Magnetic Resonance Imaging, a Feasibility Study

    Energy Technology Data Exchange (ETDEWEB)

    Seidensticker, Max, E-mail: max.seidensticker@med.ovgu.de [Universitätsklinik Magdeburg, Klinik für Radiologie und Nuklearmedizin (Germany); Burak, Miroslaw [Pomeranian Medical University, Department of Diagnostic Imaging and Interventional Radiology (Poland); Kalinski, Thomas [Universitätsklinik Magdeburg, Institut für Pathologie (Germany); Garlipp, Benjamin [Universitätsklinik Magdeburg, Klinik für Allgemein-, Viszeral- und Gefäßchirurgie (Germany); Koelble, Konrad [Philipps Universität Marburg, Fachbereich Medizin der, Abteilung für Neuropathologie (Germany); Wust, Peter [Charité Universitätsmedizin Berlin, Klinik für Radioonkologie und Strahlentherapie (Germany); Antweiler, Kai [Universitätsklinik Magdeburg, Institut für Biometrie und Medizinische Informatik (Germany); Seidensticker, Ricarda; Mohnike, Konrad; Pech, Maciej; Ricke, Jens [Universitätsklinik Magdeburg, Klinik für Radiologie und Nuklearmedizin (Germany)

    2015-02-15

    PurposeRadiotherapy of liver malignancies shows promising results (radioembolization, stereotactic irradiation, interstitial brachytherapy). Regardless of the route of application, a certain amount of nontumorous liver parenchyma will be collaterally damaged by radiation. The functional reserve may be significantly reduced with an impact on further treatment planning. Monitoring of radiation-induced liver damage by imaging is neither established nor validated. We performed an analysis to correlate the histopathological presence of radiation-induced liver damage with functional magnetic resonance imaging (MRI) utilizing hepatobiliary contrast media (Gd-BOPTA).MethodsPatients undergoing local high-dose-rate brachytherapy for whom a follow-up hepatobiliary MRI within 120 days after radiotherapy as well as an evaluable liver biopsy from radiation-exposed liver tissue within 7 days before MRI were retrospectively identified. Planning computed tomography (CT)/dosimetry was merged to the CT-documentation of the liver biopsy and to the MRI. Presence/absence of radiation-induced liver damage (histopathology) and Gd-BOPTA uptake (MRI) as well as the dose applied during brachytherapy at the site of tissue sampling was determined.ResultsFourteen biopsies from eight patients were evaluated. In all cases with histopathological evidence of radiation-induced liver damage (n = 11), no uptake of Gd-BOPTA was seen. In the remaining three, cases no radiation-induced liver damage but Gd-BOPTA uptake was seen. Presence of radiation-induced liver damage and absence of Gd-BOPTA uptake was correlated with a former high-dose exposition.ConclusionsAbsence of hepatobiliary MRI contrast media uptake in radiation-exposed liver parenchyma may indicate radiation-induced liver damage. Confirmatory studies are warranted.

  2. Radiation-Induced Liver Damage: Correlation of Histopathology with Hepatobiliary Magnetic Resonance Imaging, a Feasibility Study

    International Nuclear Information System (INIS)

    PurposeRadiotherapy of liver malignancies shows promising results (radioembolization, stereotactic irradiation, interstitial brachytherapy). Regardless of the route of application, a certain amount of nontumorous liver parenchyma will be collaterally damaged by radiation. The functional reserve may be significantly reduced with an impact on further treatment planning. Monitoring of radiation-induced liver damage by imaging is neither established nor validated. We performed an analysis to correlate the histopathological presence of radiation-induced liver damage with functional magnetic resonance imaging (MRI) utilizing hepatobiliary contrast media (Gd-BOPTA).MethodsPatients undergoing local high-dose-rate brachytherapy for whom a follow-up hepatobiliary MRI within 120 days after radiotherapy as well as an evaluable liver biopsy from radiation-exposed liver tissue within 7 days before MRI were retrospectively identified. Planning computed tomography (CT)/dosimetry was merged to the CT-documentation of the liver biopsy and to the MRI. Presence/absence of radiation-induced liver damage (histopathology) and Gd-BOPTA uptake (MRI) as well as the dose applied during brachytherapy at the site of tissue sampling was determined.ResultsFourteen biopsies from eight patients were evaluated. In all cases with histopathological evidence of radiation-induced liver damage (n = 11), no uptake of Gd-BOPTA was seen. In the remaining three, cases no radiation-induced liver damage but Gd-BOPTA uptake was seen. Presence of radiation-induced liver damage and absence of Gd-BOPTA uptake was correlated with a former high-dose exposition.ConclusionsAbsence of hepatobiliary MRI contrast media uptake in radiation-exposed liver parenchyma may indicate radiation-induced liver damage. Confirmatory studies are warranted

  3. Low Protein Diet Inhibits Uric Acid Synthesis and Attenuates Renal Damage in Streptozotocin-Induced Diabetic Rats

    Directory of Open Access Journals (Sweden)

    Jianmin Ran

    2014-01-01

    Full Text Available Aim. Several studies indicated that hyperuricemia may link to the worsening of diabetic nephropathy (DN. Meanwhile, low protein diet (LPD retards exacerbation of renal damage in chronic kidney disease. We then assessed whether LPD influences uric acid metabolism and benefits the progression of DN in streptozotocin- (STZ- induced diabetic rats. Methods. STZ-induced and control rats were both fed with LPD (5% and normal protein diet (18%, respectively, for 12 weeks. Vital signs, blood and urinary samples for UA metabolism were taken and analyzed every 3 weeks. Kidneys were removed at the end of the experiment. Results. Diabetic rats developed into constantly high levels of serum UA (SUA, creatinine (SCr and 24 h amounts of urinary albumin excretion (UAE, creatintine (UCr, urea nitrogen (UUN, and uric acid (UUA. LPD significantly decreased SUA, UAE, and blood glucose, yet left SCr, UCr, and UUN unchanged. A stepwise regression showed that high UUA is an independent risk factor for DN. LPD remarkably ameliorated degrees of enlarged glomeruli, proliferated mesangial cells, and hyaline-degenerated tubular epithelial cells in diabetic rats. Expression of TNF-α in tubulointerstitium significantly decreased in LPD-fed diabetic rats. Conclusion. LPD inhibits endogenous uric acid synthesis and might accordingly attenuate renal damage in STZ-induced diabetic rats.

  4. Protection from Experimental Cerebral Malaria with a Single Dose of Radiation-Attenuated, Blood-Stage Plasmodium berghei Parasites

    OpenAIRE

    Gerald, Noel J.; Majam, Victoria; Mahajan, Babita; Kozakai, Yukiko; Kumar, Sanjai

    2011-01-01

    Background Whole malaria parasites are highly effective in inducing immunity against malaria. Due to the limited success of subunit based vaccines in clinical studies, there has been a renewed interest in whole parasite-based malaria vaccines. Apart from attenuated sporozoites, there have also been efforts to use live asexual stage parasites as vaccine immunogens. Methodology and Results We used radiation exposure to attenuate the highly virulent asexual blood stages of the murine malaria par...

  5. Evaluation Of Coenzyme Q10 Role In Reducing Kidney Damage In Rats Induced By Acetaminophen And GAMMA Radiation Exposure

    International Nuclear Information System (INIS)

    Evaluation of coenzyme Q10 role in reducing kidney damage in rats induced by acetaminophen (APAP) and gamma radiation exposure was undertaken in the present study. Seven groups of adult male Wister albino rats were used in the present study. Renal function indicators (creatinine, blood urea and uric acid) levels were measured in the blood serum of rats. MDA, NO and LDH levels in kidney tissue were estimated. The antioxidants GSH and SOD were also examined. Histopathological changes and mast cells presence were investigated in kidney tissue. APAP and/or gamma radiation exposure revealed significant increases in MDA, NO and LDH levels. Also, significant decrease in GSH and SOD levels as compared with the control group was detected. Histological changes included tubular necrosis, hydropic degeneration, presence of interstitial inflammatory cells and atrophied glomeruli were observed in kidney tissue. Mast cells expressions in kidney tissue were detected after one day of APAP treatment for 2 weeks. Exposure of rats to gamma radiation revealed unpronounced effect on kidney tissue. Administration of coenzyme Q10 post-treatment of rats with APAP and/or gamma radiation exposure for one week apparently attenuated the levels of renal function indicators; MDA, NO and LDH.Also, a significant amelioration in GSH and SOD was observed. An improvement was detected in kidney tissue and mast cells expression of rats after treatment with coenzyme Q10. In conclusion, coenzyme Q10 apparently protects rats from the dangerous effect of APAP and gamma radiation exposure.

  6. Alpha-Lipoic Acid Attenuates Oxidative Damage in Organs After Sepsis.

    Science.gov (United States)

    Petronilho, Fabricia; Florentino, Drielly; Danielski, Lucinéia Gainski; Vieira, Luiz Carlos; Martins, Maryane Modolon; Vieira, Andriele; Bonfante, Sandra; Goldim, Mariana Pereira; Vuolo, Francieli

    2016-02-01

    Sepsis progression is linked with the imbalance between reactive oxygen species and antioxidant enzymes. Thus, the aim of this study was to evaluate the effect of alpha-lipoic acid (ALA), a powerful antioxidant, in organs of rats submitted to sepsis. Male Wistar rats were subjected to sepsis by cecal ligation puncture (CLP) and treated with ALA or vehicle. After CLP (12 and 24 h), the myeloperoxidase (MPO) activity, protein and lipid oxidative damage, and antioxidant enzymes in the liver, kidney, heart, and lung were evaluated. ALA was effective in reducing MPO activity, lipid peroxidation in the liver, and protein carbonylation only in the kidney in 12 h after CLP. In 12 h, SOD activity increased in the kidney and CAT activity in the liver and kidney with ALA treatment. Thus, ALA was able to reduce the inflammation and oxidative stress in the liver and kidney after sepsis in rats. PMID:26431839

  7. Quercetin Attenuates Testicular Damage and Oxidative Stress in Streptozotocin-induced Diabetic Rats

    Directory of Open Access Journals (Sweden)

    Osama A. Alkhamees

    2014-04-01

    Full Text Available The present study aims to examine the influence of Quercetin (QR in testis of Streptozotocin (STZ-induced diabetic rats. Diabetes was induced by a single injection of STZ (65 mg/kg, ip. Quercetin (25 and 50 mg/kg/day was treated to normal and diabetic rats for 5 weeks. In serum, glucose, testosterone, Interleukin-6 (IL-6, Interleukin-1beta (IL-1&beta and Tumor Necrosis Factor-α (TNF-&alpha levels were estimated and in testis tissues Thiobarbituric Acid Reactive Substances (TBARS, sulfhydryl groups, nucleic acids and Total Protein (TP levels were estimated. Superoxide Dismutase (SOD, Catalase (CAT and Glutathione-S-Transferase (GST activities were also determined in testicular cells. In penile tissue cyclic Guanosine Monophosphate (cGMP levels were measured. Histopathological changes were evaluated in a cross-section of testis. Testosterone levels were decreased while pro-inflammatory markers were increased in diabetic rats. QR treatment to diabetic rats corrected these changes. In penile tissues cGMP content was markedly inhibited and normalized by the QR treatment. In STZ-induced diabetic rats, TBARS levels were significantly increased while T-GSH, NP-SH, DNA, RNA and TP levels were decreased and in QR treated groups showed significant inhibition in increased TBARS levels and decreased T-GSH and NP-SH levels. The inhibited activities of SOD, CAT and GST in testicular cells of diabetic rats were increased after QR treatment. The reduced levels of nucleic acids and TP in diabetic rats were markedly corrected in QR treated groups. Histopathological evaluation revealed damage in testicular cells of diabetic rats and the treatment with QR showed protection. These results suggest that, QR supplementation to STZ-induced diabetic rats for five consecutive weeks is a potentially beneficial agent to reduce testicular damage in adult diabetic rats, probably by decreasing oxidative stress.

  8. Silencing MR-1 attenuates inflammatory damage in mice heart induced by AngII

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Wenjian [Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Key Lab of Antibiotic Biotechnology, Ministry of Health, Beijing 100050 (China); Hunan Environment-Biological Polytechnic College, Hengyang Hunan 421005 (China); Chen, Haiyang [Hunan Environment-Biological Polytechnic College, Hengyang Hunan 421005 (China); Jiang, Jiandong [Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Key Lab of Antibiotic Biotechnology, Ministry of Health, Beijing 100050 (China); Kong, Weijia, E-mail: wjkong894@sohu.com [Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Key Lab of Antibiotic Biotechnology, Ministry of Health, Beijing 100050 (China); Wang, Yiguang, E-mail: wangyh456@yahoo.com.cn [Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Key Lab of Antibiotic Biotechnology, Ministry of Health, Beijing 100050 (China)

    2010-01-15

    Myofibrillogenesis regulator-1(MR-1) can aggravate cardiac hypertrophy induced by angiotensin(Ang) II in mice through activation of NF-{kappa}B signaling pathway, and nuclear transcription factor (NF)-{kappa}B and activator protein-1(AP-1) regulate inflammatory and immune responses by increasing the expression of specific inflammatory genes in various tissues including heart. Whether inhibition of MR-1 expression will attenuate AngII-induced inflammatory injury in mice heart has not been explored. Herein, we monitored the activation of NF-{kappa}B and AP-1, together with expression of pro-inflammatory of interleukin(IL)-6, tumor necrosis factor(TNF)-{alpha}, vascular-cell adhesion molecule (VCAM)-1, platelet endothelial cell adhesion molecule (PECAM), and inflammatory cell infiltration in heart of mice which are induced firstly by AngII (PBS),then received MR-1-siRNA or control-siRNA injecting. We found that the activation of NF-{kappa}B and AP-1 was inhibited significantly, together with the decreased expression of IL-6, TNF-{alpha}, VCAM-1, and PECAM in AngII-induced mice myocardium in MR-1-siRNA injection groups compared with control-siRNA injecting groups. However, the expression level of MR-1 was not an apparent change in PBS-infused groups than in unoperation groups, and MR-1-siRNA do not affect the expression of MR-1 in PBS-infused mice. Our findings suggest that silencing MR-1 protected mice myocardium against inflammatory injury induced by AngII by suppression of pro-inflammatory transcription factors NF-{kappa}B and AP-1 signaling pathway.

  9. Iron influence in self-attenuation of gamma radiation in sand samples

    Energy Technology Data Exchange (ETDEWEB)

    Aquino, Reginaldo R.; Cavalcante, Fernanda; Pecequilo, Brigitte R.S, E-mail: raquino@ipen.br, E-mail: fcavalcante@ipen.br, E-mail: brigitte@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil)

    2013-07-01

    Self-attenuation of gamma rays are usually observed in sand samples, due to the presence of iron particles of natural or anthropogenic causes, which may lead to misleading activities concentrations results. As iron atoms are often present in sand samples, the self-attenuation contribution from this mineral requires special attention when assessing sand samples radioactivity. This contributions in verified in the in the present study, using several silica (sand-like) samples doped with different concentrations of iron. The samples were arranged with pure SiO{sub 4} (98,9%) mineral from the region of Setiba, (Espirito Santo state, Brazil) and Itabirito mineral, from Itabira (Minas Gerais state, Brazil), using standard 100 mL high density polyethylene (HDPE) flat-botton cylindrical flasks, each sealed using a 52.5 mm plan screw cap and bubble spigot. Three samples were arranged in different concentrations - Fe 25% and SiO{sub 4} 75%; Fe 50% and SiO{sub 4} 50%; Fe 75% and SiO{sub 4} 25% and two other samples were assembled in the same geometry, using 100% SiO{sub 4} and 100% Fe. These samples were exposed to a large spectrum of gamma radiation (121 keV to 1408 keV) emitted by sources of {sup 60}Co, {sup 137}Cs and {sup 152}Eu. These gamma radiations were collimated and directed over the doped samples in a high resolution gamma ray spectrometer, whose spectra were analyzed with the Winner Gamma software. The matrix effect intensity is inferred by the percentage differences observed in varying the iron concentration that proved to be more intense for lower energy radiation. (author)

  10. Cytogenetic techniques as biological indicator and dosimeter of radiation damage

    International Nuclear Information System (INIS)

    Full text: The cytogenetic methods are established techniques for bio monitoring and bio dosimetry of professionally and accidentally exposed to ionizing radiation subjects. They are applied to continue the evaluation of the physical dosimetry and to consider the individual radiosensitivity. The results of cytogenetic monitoring and dosimetry of radiation exposed subjects carried out during the last 5 years in laboratory of Radiation Genetics, NCRRP is reported. Laboratory of Radiation genetics performs cytogenetic monitoring of low dose radiation professionally or medically exposed subjects: workers in Kozloduy NPP, radioactive waste repository workers, X-rays diagnostically exposed patients, and radiotherapy exposed as well. Three cytogenetic indicators are applied as the most sensitive indicators for human radiation exposure: analysis of micronuclei (MN), chromosomal aberrations (CA) and stable translocations (FISH). The optimized methodology for application of different cytogenetic techniques for radiation estimation is discussed

  11. Non-Destructive Detection and Separation of Radiation Damaged Cells in Miniaturized, Inexpensive Device Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Our objective is to develop and demonstrate a novel microfluidic device for non-destructive identification, sorting and counting of radiation damaged cells. A major...

  12. Non-Destructive Detection and Separation of Radiation Damaged Cells in Miniaturized, Inexpensive Device Project

    Data.gov (United States)

    National Aeronautics and Space Administration — There is a clear and well-identified need for rapid, efficient, non-destructive detection and isolation of radiation damaged cells. Available commercial...

  13. The Effect of Various Waste Materials’ Contents on the Attenuation Level of Anti-Radiation Shielding Concrete

    OpenAIRE

    Rafiza Abdul Razak; Andrei Victor Sandu; Kahtan S. Mohammed; Kamarudin Hussin; Mohd Mustafa Al Bakri Abdullah; Ali Basheer Azeez

    2013-01-01

    Samples of concrete contain various waste materials, such as iron particulates, steel balls of used ball bearings and slags from steel industry were assessed for their anti-radiation attenuation coefficient properties. The attenuation measurements were performed using gamma spectrometer of NaI (Tl) detector. The utilized radiation sources comprised 137Cs and 60Co radioactive elements with photon energies of 0.662 MeV for 137Cs and two energy levels of 1.17 and 1.33 MeV for the 60Co. Likewise ...

  14. Radiation Damage of the ATLAS Pixel Sensors Using Leakage Current Measurement System

    CERN Document Server

    Gorelov, I; The ATLAS collaboration

    2013-01-01

    The current measurement system measures directly the leakage current in pixel sensors. The system is integrated with the ATLAS Pixel high voltage delivery system. The system runs as a monitor of a radiation damage of the pixel sensors. The leakage current data collected for the completed data taking period are analyzed. The recent status of the sensor's radiation damage and a comparison with the theoretical predictions are presented.

  15. The Radiation environment and damage in the CDF tracking volume

    Energy Technology Data Exchange (ETDEWEB)

    R. J. Tesarek et al.

    2003-12-16

    The authors present direct measurements of the spatial distribution of ionizing radiation and low energy neutrons (E{sub n} < 200 keV) inside the tracking volume of the collider detector at Fermilab (CDF). Using data from multiple exposures, the radiation field can be separated into components from beam losses and collisions and can be checked for consistency between the measurements. They compare the radiation measurements with an increase in the leakage currents of the CDF silicon detectors and find reasonable agreement.

  16. Lycopene attenuates dichlorvos-induced oxidative damage and hepatotoxicity in rats.

    Science.gov (United States)

    El-Saad, Am Abu; Ibrahim, M M; Hazani, A A; El-Gaaly, G A

    2016-06-01

    Because of the widespread use of dichlorvos (DDVP) for domestic applications, evaluation of their toxic effects is of major concern to public health. Lycopene may lower oxidative stress by a mechanism that is not fully elucidated. The present study was undertaken to evaluate the protective efficacy of lycopene in terms of normalization of altered biochemical parameters following DDVP treatment in rats. Animals were divided into four groups. The first group was used as control, while groups 2, 3, and 4 were orally treated with lycopene (10 mg kg(-1) body weight (b.w.)), DDVP (1.6 mg kg(-1) b.w.), and DDVP plus lycopene, respectively. Results showed that oral administration of DDVP for 30 days increased the levels of lipid peroxidation markers such as malondialdehyde, 4-hydroxynonanal, and protein carbonyl content in liver. Also, a decrease in levels of vitamin C, vitamin E, and reduced glutathione was detected due to DDVP administration. These were accompanied by a decrease in the activities of antioxidant enzymes superoxide dismutase, catalase, glutathione peroxidase, and glutathione-S-transferase in the liver tissue. Moreover, DDVP increased the activities of serum transaminases, alkaline phosphatase, lactate dehydrogenase, and lipoxygenase, and the levels of bilirubin, total cholesterol, low-density lipoprotein cholesterol, triglyceride and DNA-protein crosslinks, and 8-hydroxy-2-deoxyguanosine, while decreased the level of high-density lipoprotein cholesterol. Our results provide new insights into the biochemical studies of relation between DDVP hepatotoxicity and lycopene treatment. Administration of lycopene to DDVP-treated rats reverted the status of hepatic markers to near-normal levels. These data suggest that lycopene can protect against the liver damage induced by DDVP. PMID:26231422

  17. Status of radiation damage measurements in room temperature semiconductor radiation detectors

    International Nuclear Information System (INIS)

    The literature of radiation damage measurements on cadmium zinc telluride (CZT), cadmium telluride (CT), and mercuric iodide (HgI2) is reviewed for the purpose of determining their applicability to space applications. CZT strip detectors exposed to intermediate energy (1.3 MeV) proton fluences exhibit increased interstrip leakage after 1010 p/cm2 and significant bulk leakage after 1012 p/cm2. CZT exposed to 200 MeV protons shows a two-fold loss in energy resolution after a fluence of 5 x 109 p/cm2 in thick (3 mm) planar devices but little effect in 2 mm devices. No energy resolution effects were noted from moderated fission spectrum neutrons after fluences up to 1010 n/cm2, although activation was evident. CT detectors show resolution losses after fluences of 3 x 109 p/cm2 at 33 MeV for chlorine-doped detectors. Indium doped material may be more resistant. Neutron exposures (8 MeV) caused resolution losses after fluences of 2 x 1010 n/cm2. Mercuric iodide has been studied with intermediate energy protons (10 to 33 MeV) at fluences up to 1012 p/cm2 and with 1.5 GeV protons at fluences up to 1.2 x 108 p/cm2. Neutron exposures at 8 MeV have been reported at fluences up to 1015 n/cm2. No radiation damage was found under these irradiation conditions

  18. Shielding data for hadron-therapy ion accelerators: Attenuation of secondary radiation in concrete

    CERN Document Server

    Agosteo, S; Sagia, E; Silari, M

    2014-01-01

    The secondary radiation field produced by seven different ion species (from hydrogen to nitrogen), impinging onto thick targets made of either iron or ICRU tissue, was simulated with the FLUKA Monte Carlo code, and transported through thick concrete shields: the ambient dose equivalent was estimated and shielding parameters evaluated. The energy for each ion beam was set in order to reach a maximum penetration in ICRU tissue of 290 mm (equivalent to the therapeutic range of 430 MeV/amu carbon ions). Source terms and attenuation lengths are given as a function of emission angle and ion species, along with fits to the Monte Carlo data, for shallow depth and deep penetration in the shield. Trends of source terms and attenuation lengths as a function of neutron emission angle and ion species impinging on tar- get are discussed. A comparison of double differential distributions of neutrons with results from similar simulation works reported in the literature is also included. The aim of this work is to provide shi...

  19. Protection from radiation injury through oral administration of PF4 gene carried by attenuated salmonella

    International Nuclear Information System (INIS)

    Objective: To investigate the in vivo radiation protection effect of PF4 by oral administration of attenuated salmonella as the carrier in mice. Methods: The eukaryotic vector pIRES2-EGFP-carried PF4 gene was transferred into an aroA-autotrophic mutant of salmonella typhimurium (SL3261), which was administered orally to BALBPc mice at 1x108 PFu once every interval three days. At 12 hours after the third oral administration the mice were subjected to a total body irradiation (TBI) of 700 cGy by a 60Co source. The protective effect of SL3261/PF4 was determined by detection GFP ( green fluorescence protein) expression in tissues, peripheral blood count, culture of bone marrow colony-forming cells and survival time of mice. Results: Expression of GFP could be detected in the liver, spleen, intestine, kidney, peripheral blood and bone marrow. On days 7 and 14 after irradiation, Compared to controls, there were obvious differences in number of bone marrow mononuclear cells, CFU-GM (granulocyte-macrophage colony-forming unit ) and HPP-CFC (high proliferating potential-colony-forming cells) of mice treated with SL3261/PF4 (P<0.05) as well as prolongation of the survival time. Conclusion: These data demonstrate for the first time that PF4 protects mice from TBI injury and accelerates recovery of hematopoiesis by oral administration of attenuated salmonella carrying PF4 gene. (authors)

  20. Toxicity attenuation optimization of crotalic venom by gamma radiation and studies of its immunogenic properties

    International Nuclear Information System (INIS)

    Literature data show that 2.0 kGy dose of gamma radiation, generated by 60 source, reduces the toxic activity of Crotalus durissus terrificus venom, without altering its immunogenic capacity. When crotoxin, main toxin from crotalic venom, was irradiated with the same dose, toxicity was also reduced and the immunogenicity was maintained. This fact was attributed to aggregates (compounds with high molecular weight generated during irradiation), that showed no toxicity but were able to induce the antibodies formation against native venom. Crotalus durissus terrificus venom was irradiated with 2.0, 3.0, 5.0 and 10.0 kGy doses and submitted to molecular exclusion chromatography, in order to find an efficient dose that produces large amounts of non toxic but still immunogenic aggregates. After being isolated, the products of irradiation were evaluated for the amount produced, molecular alteration, and toxic and immunogenic activities. These parameters were also analyzed for the whole venom irradiated. The results from different doses irradiated venom were compared with native one, and 2.0 kGy dose was confirmed to be the most efficient in the association of toxicity attenuation with maintenance of immunogenicity of the crotalic venom, while other doses, in spite of being efficient in the toxicity attenuation, they were not able to keep the immunogenicity property. So, the dose of 2.0 kGy could be used to immunize animals in order to improve anticrotalic sera production. (author)

  1. Maximum entropy inference of seabed attenuation parameters using ship radiated broadband noise.

    Science.gov (United States)

    Knobles, D P

    2015-12-01

    The received acoustic field generated by a single passage of a research vessel on the New Jersey continental shelf is employed to infer probability distributions for the parameter values representing the frequency dependence of the seabed attenuation and the source levels of the ship. The statistical inference approach employed in the analysis is a maximum entropy methodology. The average value of the error function, needed to uniquely specify a conditional posterior probability distribution, is estimated with data samples from time periods in which the ship-receiver geometry is dominated by either the stern or bow aspect. The existence of ambiguities between the source levels and the environmental parameter values motivates an attempt to partially decouple these parameter values. The main result is the demonstration that parameter values for the attenuation (α and the frequency exponent), the sediment sound speed, and the source levels can be resolved through a model space reduction technique. The results of this multi-step statistical inference developed for ship radiated noise is then tested by processing towed source data over the same bandwidth and source track to estimate continuous wave source levels that were measured independently with a reference hydrophone on the tow body. PMID:26723313

  2. Nuclear data for radiation damage assessment and related safety aspects 1989

    International Nuclear Information System (INIS)

    The first Advisory Group Meeting on Nuclear Data for Radiation Damage Assessment and Related Safety Aspects was convened by NDS eight years ago in October 1981. The present meeting was a second one on this topic and it was intended to summarize the progress and status of nuclear data for radiation damage assessment since the first meeting. The participants have emphasized that since the first meeting a number of spallation neutron sources were put into operation and many material radiation damage studies are conducted now at these facilities. The distinguishing feature of spallation neutron sources is that the neutron energy spectra which they produce in most cases have a high energy component which may give a significant contribution to radiation damage. The proper understanding of radiation damage experiments in these neutron fields requires a better knowledge of nuclear data at high neutron energies. These ideas were formulated in detail in the conclusions and recommendations of the participants which are contained in this report. Another new issue was the need for activation cross-section data of long-lived isotopes. This topic is also considered in the conclusions below. The 14 presentations published in this proceedings were subdivided into three sessions: Characterization of neutron reactor environment, surveillance and nuclear data (5 papers); High energy neutron dosimetry and radiation damage calculations (6 papers); REAL-88 results and prospects (3 papers). A separate abstract was prepared for each of these papers. Refs, figs and tabs

  3. Statistical uncertainty in educational experiment on the attenuation of gamma radiation

    CERN Document Server

    Pilakouta, Mirofora

    2011-01-01

    Due to time and financial restrictions in an educational laboratory, we are making compromises, using experimental setups in which limitations and uncertainties are important. In these cases we should pay particular attention to the role of different factors that affect our experiment, in order to achieve the best possible educational outcome and to avoid misconceptions. In this paper problems related to the use of very low activity source 60Co in the experiment of measuring the linear attenuation coefficient of gamma rays through matter, will be presented. The role of background radiation in measurements and in the relative statistical uncertainty as well as the role of statistical uncertainty in the choice of representative measurements is discussed. Moreover students' difficulties and misconceptions related mainly to the statistical uncertainty and its connection to measurements overlapping are recorded. An explanation for the possible reasons of these misunderstandings is attempted in order to improve the...

  4. Phenolic antioxidants attenuate hippocampal neuronal cell damage against kainic acid induced excitotoxicity

    Indian Academy of Sciences (India)

    M S Parihar; Taruna Hemnani

    2003-02-01

    WS + CP + AV. However, when CP and AV were given alone, the changes in the GPx activity and GSH content were not significant. Although the major factors involved in these properties of phytochemicals remain to be specified, the finding of this study has suggested that phytochemicals present in plant extracts mitigate the effects of excitotoxicity and oxidative damage in hippocampus and this might be accomplished by their antioxidative properties.

  5. Cranial Radiation Therapy and Damage to Hippocampal Neurogenesis

    Science.gov (United States)

    Monje, Michelle

    2008-01-01

    Cranial radiation therapy is associated with a progressive decline in cognitive function, prominently memory function. Impairment of hippocampal neurogenesis is thought to be an important mechanism underlying this cognitive decline. Recent work has elucidated the mechanisms of radiation-induced failure of neurogenesis. Potential therapeutic…

  6. Synchrotron radiation damage on insulating materials of TRISTAN magnets

    International Nuclear Information System (INIS)

    The shielding design to protect the coils of the bending magnet against synchrotron radiation was performed. The absorbed doses to the magnet components, particularly on the insulating material such as epoxy resin of coil or rubber hoses for water cooling, were measured. The property against radiation exposure was studied. 6 refs., 5 figs

  7. Time-scale invariances in preseismic electromagnetic radiation, magnetization and damage evolution of rocks

    Directory of Open Access Journals (Sweden)

    Y. Kawada

    2007-10-01

    Full Text Available We investigate the time-scale invariant changes in electromagnetic and mechanical energy releases prior to a rock failure or a large earthquake. The energy release processes are caused by damage evolutions such as crack propagation, motion of charged dislocation, area-enlargement of sheared asperities and repetitive creep-rate changes. Damage mechanics can be used to represent the time-scale invariant evolutions of both brittle and plastic damages. Irreversible thermodynamics applied to the damage mechanics reveals that the damage evolution produces the variations in charge, dipole and electromagnetic signals in addition to mechanical energy release, and yields the time-scale invariant patterns of Benioff electromagnetic radiation and cumulative Benioff strain-release. The irreversible thermodynamic framework of damage mechanics is also applicable to the seismo-magnetic effect, and the time-scale invariance is recognized in the remanent magnetization change associated with damage evolution prior to a rock failure.

  8. Calculation of radiation attenuation coefficients in Portland cements mixed with silica fume, blast furnace slag and natural zeolite

    International Nuclear Information System (INIS)

    This paper presents the radiation attenuation coefficients expressed as mass attenuation coefficients for Portland cement, zeolite, blast furnace slag, silica fume and their mixed types in function of the Photon energy over the energy range of 1 keV to 2 MeV. It was observed that different percentages of constituents in cement and cement mixed with different additives such as zeolite, silica fume and blast furnace slag, lead to significant variations in total mass attenuation coefficients. The elemental compositions of samples were analyzed using a wavelength dispersive XRF spectrometer. The calculated values of total mass attenuation coefficients were discussed on the basis of different percentages of constituents of cement and cement mixed with different additives

  9. Both Complexity and Location of DNA Damage Contribute to Cellular Senescence Induced by Ionizing Radiation

    Science.gov (United States)

    Zhang, Xurui; Ye, Caiyong; Sun, Fang; Wei, Wenjun; Hu, Burong; Wang, Jufang

    2016-01-01

    Persistent DNA damage is considered as a main cause of cellular senescence induced by ionizing radiation. However, the molecular bases of the DNA damage and their contribution to cellular senescence are not completely clear. In this study, we found that both heavy ions and X-rays induced senescence in human uveal melanoma 92–1 cells. By measuring senescence associated-β-galactosidase and cell proliferation, we identified that heavy ions were more effective at inducing senescence than X-rays. We observed less efficient repair when DNA damage was induced by heavy ions compared with X-rays and most of the irreparable damage was complex of single strand breaks and double strand breaks, while DNA damage induced by X-rays was mostly repaired in 24 hours and the remained damage was preferentially associated with telomeric DNA. Our results suggest that DNA damage induced by heavy ion is often complex and difficult to repair, thus presents as persistent DNA damage and pushes the cell into senescence. In contrast, persistent DNA damage induced by X-rays is preferentially associated with telomeric DNA and the telomere-favored persistent DNA damage contributes to X-rays induced cellular senescence. These findings provide new insight into the understanding of high relative biological effectiveness of heavy ions relevant to cancer therapy and space radiation research. PMID:27187621

  10. Both Complexity and Location of DNA Damage Contribute to Cellular Senescence Induced by Ionizing Radiation.

    Science.gov (United States)

    Zhang, Xurui; Ye, Caiyong; Sun, Fang; Wei, Wenjun; Hu, Burong; Wang, Jufang

    2016-01-01

    Persistent DNA damage is considered as a main cause of cellular senescence induced by ionizing radiation. However, the molecular bases of the DNA damage and their contribution to cellular senescence are not completely clear. In this study, we found that both heavy ions and X-rays induced senescence in human uveal melanoma 92-1 cells. By measuring senescence associated-β-galactosidase and cell proliferation, we identified that heavy ions were more effective at inducing senescence than X-rays. We observed less efficient repair when DNA damage was induced by heavy ions compared with X-rays and most of the irreparable damage was complex of single strand breaks and double strand breaks, while DNA damage induced by X-rays was mostly repaired in 24 hours and the remained damage was preferentially associated with telomeric DNA. Our results suggest that DNA damage induced by heavy ion is often complex and difficult to repair, thus presents as persistent DNA damage and pushes the cell into senescence. In contrast, persistent DNA damage induced by X-rays is preferentially associated with telomeric DNA and the telomere-favored persistent DNA damage contributes to X-rays induced cellular senescence. These findings provide new insight into the understanding of high relative biological effectiveness of heavy ions relevant to cancer therapy and space radiation research. PMID:27187621

  11. Both Complexity and Location of DNA Damage Contribute to Cellular Senescence Induced by Ionizing Radiation.

    Directory of Open Access Journals (Sweden)

    Xurui Zhang

    Full Text Available Persistent DNA damage is considered as a main cause of cellular senescence induced by ionizing radiation. However, the molecular bases of the DNA damage and their contribution to cellular senescence are not completely clear. In this study, we found that both heavy ions and X-rays induced senescence in human uveal melanoma 92-1 cells. By measuring senescence associated-β-galactosidase and cell proliferation, we identified that heavy ions were more effective at inducing senescence than X-rays. We observed less efficient repair when DNA damage was induced by heavy ions compared with X-rays and most of the irreparable damage was complex of single strand breaks and double strand breaks, while DNA damage induced by X-rays was mostly repaired in 24 hours and the remained damage was preferentially associated with telomeric DNA. Our results suggest that DNA damage induced by heavy ion is often complex and difficult to repair, thus presents as persistent DNA damage and pushes the cell into senescence. In contrast, persistent DNA damage induced by X-rays is preferentially associated with telomeric DNA and the telomere-favored persistent DNA damage contributes to X-rays induced cellular senescence. These findings provide new insight into the understanding of high relative biological effectiveness of heavy ions relevant to cancer therapy and space radiation research.

  12. Photoinduced processes, radiation interaction with material and damages - material hardness

    Directory of Open Access Journals (Sweden)

    Srećković Milesa Ž.

    2015-01-01

    Full Text Available Photo and nuclear radiation induced processes are considered through the interaction of radiation with semiconducting, metallic and other materials, including the scintillator materials. The improvement of component efficiency by the use of quantum generators, trimming and hybrid processes with nuclear radiation has been analyzed. The studied processes can be positive or negative depending on application. Besides the experimental approach to the processes and chosen interactions, the analytical description of our experiments, as well as ones from other references, has been performed. The contemporary couplings between the nuclear physics, laser techniques and respective dosimetric aspects have been considered. [Projekat Ministarstva nauke Republike Srbije, br. II45003 i br. TP 35046

  13. X-ray attenuation measurements for high-temperature materials characterization and in-situ monitoring of damage accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Baaklini, G.Y.

    1991-01-01

    The scope of this study was to develop and apply x-ray attenuation measurement systems that are capable of (1) characterizing density variations in high-temperature materials, e.g., monolithic ceramics and ceramic and intermetallic-matrix composites, and (2) noninvasively monitoring damage accumulation and failure sequences in ceramic-matrix composites under room-temperature tensile testing. This thesis resulted in the development of (1) a point-scan digital radiography system and (2) an in-situ x-ray material testing system. The former is used to characterize silicon carbide and silicon nitride specimens, and the latter is used to image the failure behavior of silicon carbide fiber reinforced reaction bonded silicon nitride matrix composites. Further, state of the art x-ray computed tomography is investigated to determine its capabilities and limitations in characterizing density variations of subscale engine components. Microfocus radiography, conventional radiography, scanning acoustic microscopy, and metallography are used to substantiate the x-ray computed tomography findings.

  14. MicroRNA-155 deficiency promotes nephrin acetylation and attenuates renal damage in hyperglycemia-induced nephropathy.

    Science.gov (United States)

    Lin, Xu; You, Yanwu; Wang, Jie; Qin, Youling; Huang, Peng; Yang, Fafen

    2015-04-01

    MiR-155 has been reported to be involved in both innate and adaptive immune responses. But the role of miR-155 in hyperglycemia-induced nephropathy is still unknown. In our current study, 3-month-old male wild-type C57 mice and Mir-155(-/-) mice were used to establish hyperglycemia-induced nephropathy. In our hyperglycemia-induced nephropathy model, the expression of podocyte injury marker desmin was markedly increased in the diabetes group when compared with control. Diabetes also significantly decreased the levels of nephrin and acetylated nephrin, whereas the expression of miR-155 was markedly increased in diabetes group when compared with control. MiR-155(-/-) mice showed significantly increased expression of nephrin, acetylated nephrin, and Wilm's tumor-1 protein (WT-1) when compared with wild-type control. MiR-155 deficiency results in significantly decrease in IL-17A expression both in vivo and in vitro. And the increased expression of WT-1, nephrin, and ac-nephrin was reversed with additional treatment of rmIL-17. Furthermore, we found that the inhibited Th17 differentiation induced by miR-155 deficiency was dependent on increased expression of SOCS1. In conclusion, miR-155 deficiency promotes nephrin acetylation and attenuates renal damage in hyperglycemia-induced nephropathy. This was associated with inhibited IL-17 production through enhancement of SOCS1 expression. PMID:24969676

  15. The MRI marker gene MagA attenuates the oxidative damage induced by iron overload in transgenic mice.

    Science.gov (United States)

    Guan, Xiaoying; Jiang, Xinhua; Yang, Chuan; Tian, Xiumei; Li, Li

    2016-06-01

    We aimed to create transgenic (Tg) mice engineered for magnetic resonance imaging (MRI). To ascertain if MagA expression contributes to oxidative stress and iron metabolism, we report the generation of Tg mice in which ubiquitous expression of MagA can be detected by MRI in vivo. Expression of MagA in diverse tissues of Tg mice was assessed, and iron accumulation and deposition of nanoparticles in tissues were analyzed. Levels of antioxidant enzymes, lipid peroxidation and cytokine production were determined, and iron metabolism-related proteins were also detected. MagA Tg showed no apparent pathologic symptoms and no histologic changes compared with wild-type (WT) mice. Overexpression of MagA resulted in specific alterations of the transverse relaxation rate (R2) of water. Transgene-dependent changes in R2 were detectable by MRI in iron-overloaded mice. We also evaluated antioxidant abilities between WT and Tg groups or two iron-overloaded groups. Together with the data of cytokines and iron metabolism-related proteins, we inferred that MagA could regulate nanoparticle production and thus attenuate the oxidative damage induced by iron overload. The novel MagA Tg mouse, which expresses an MRI reporter in many tissues, would be a valuable model of MagA molecular imaging in which to study diseases related to iron metabolism. PMID:26488480

  16. Effect of estrogen receptor on radiation-induced damage to DNA

    Czech Academy of Sciences Publication Activity Database

    Běgusová, Marie; Štísová, Viktorie

    Potsdam near Berlin: -, 2005. s. 25. [RADAM conference 2005: Radiation Damage in Biomolecular Systems. 17.3.-20.3.2005, Potsdam near Berlin] R&D Projects: GA MŠk 1P05OC085 Institutional research plan: CEZ:AV0Z10480505 Keywords : estrogen receptor * estrogen response element * ionizing radiation Subject RIV: BO - Biophysics

  17. Evidence of Dopant Type-Inversion and Other Radiation Damage Effects of the CDF Silicon Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Ballarin, Roberto [Univ. of the Basque Country, Leioa (Spain)

    2010-06-01

    The aim of this document is to study the effect of radiation damage on the silicon sensors. The reflection of the effect of radiation can be observed in two fundamental parameters of the detector: the bias current and the bias voltage. The leakage current directly affects the noise, while the bias voltage is required to collect the maximum signal deposited by the charged particle.

  18. Biomarkers of DNA and cytogenetic damages induced by environmental chemicals or radiation

    International Nuclear Information System (INIS)

    This paper presents and discusses results from the studies on various biomarkers of the DNA and cytogenetic damages induced by environmental chemicals or radiation. Results of the biomonitoring studies have shown that particularly in the condition of Poland, health hazard from radiation exposure is overestimated in contradistinction to the environmental hazard

  19. Increase of Grain Boundary Mobility by Radiation Damage under Thermal Gradient Condition using Molecular Dynamics Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Woongkee; Kaviany, Massoud Kaviany; Shim, Jihoon [Pohang University of Science and Technology, Pohang (Korea, Republic of)

    2015-05-15

    Most transformations of microstructure, such as recrystallization, grain growth are based on migration of grain boundaries. These transformations greatly influence on thermal, electrical transport and mechanical properties of materials. Material industries always set aim to design and produce decent materials by controlling microstructure evolution under various conditions. Since understanding grain boundary migration is critical for predicting the microstructural evolution in material, it has been very widely investigated for several decades. Also simple information from GB migration can give the clue to depict complicated and scale-up microstructural evolution. In this work, we investigated the grain boundary migration after the radiation damage. Without radiation damage, thermal gradient driving force was insufficient to cause the movement of grain boundary. However, with introduction of radiation damage, grain boundary showed the migration behavior while it is restored from damaged state. This is due to the fact that kinetic energy of energetic particles trigger the migration of GB by increasing temperature at GB region enormously. Rapid collision supplies the energy to exceed energy barrier to make the movement of migration As temperature of local region goes up due to radiation damage, mobility of GB should rise according to the eq.2. Therefore, radiation damage act as the trigger of local gratin boundary migration.

  20. Integral (effective) and differential linear coefficients of X-ray bremsstrahlung attenuation and effective build up factors of scattered radiation

    International Nuclear Information System (INIS)

    Computer calculations of the values of integral (effective) and differential linear factors of X-ray bremsstrahlung attenuation for radiation flaw detection were conducted. The values of effective build up factors of scattered radiation were calculated as well. Calculations were conducted in geometry of ''narrow'' beam in 20-400 kV range of tube voltage for Mg, Al, Ti, Fe base alloys of 1-500 mm thickness. Calculation data are tabulated

  1. Damage by radiation in structural materials of BWR reactor vessels

    International Nuclear Information System (INIS)

    The structural materials which are manufactured the pressure vessels of the BWR reactors undergo degradation in their mechanical properties mainly due to the damage produced by the fast neutrons (E> 1 MeV) coming from the reactor core. The mechanisms of neutron damage in this type of materials are experimentally studied, through the irradiation of vessel steel in experimental reactors for a quickly ageing. Alternately the neutron damage through steel irradiation with heavy ions is simulated. In this work the first results of the damage induced by irradiation of a similar steel to the vessel of a BWR reactor are shown. The irradiation was performed with fast neutrons (E> 1 MeV, fluence of 1.45 x 1018 n/cm2) in the TRIGA Mark III Salazar reactor and separately with Ni+3 ions in a Tandetrom accelerator (E= 4.8 MeV and an ion flux rank of 0.1 to 53 ions/A2). (Author)

  2. Integrated Molecular Analysis Indicates Undetectable Change in DNA Damage in Mice after Continuous Irradiation at ~ 400-fold Natural Background Radiation

    OpenAIRE

    Olipitz, Werner; Wiktor-Brown, Dominika; Shuga, Joe; Pang, Bo; McFaline, Jose; Lonkar, Pallavi; Thomas, Aline; Mutamba, James T; Greenberger, Joel S.; Samson, Leona D.; Dedon, Peter C; Yanch, Jacquelyn C.; Engelward, Bevin P.

    2012-01-01

    Background: In the event of a nuclear accident, people are exposed to elevated levels of continuous low dose-rate radiation. Nevertheless, most of the literature describes the biological effects of acute radiation. Objectives: DNA damage and mutations are well established for their carcinogenic effects. We assessed several key markers of DNA damage and DNA damage responses in mice exposed to low dose-rate radiation to reveal potential genotoxic effects associated with low dose-rate radiation....

  3. Concrete alkali-silica reaction and nuclear radiation damage

    International Nuclear Information System (INIS)

    The deterioration of concrete by alkali-silica reaction of aggregates (ASR) and the effect of nuclear radiations on the ASR have been reviewed based on our studies on the mechanism of ASR and the effect of nuclear radiations on the resistivity of minerals to alkaline solution. It has been found that the ASR is initiated by the attack of alkaline solution in concrete to silicious aggregates to convert them into hydrated alkali silicate. The consumption of alkali hydroxide by the aggregates induces the dissolution of Ca2+ ions into the solution. The alkali silicate surrounding the aggregates then reacts with Ca2+ ions to convert to insoluble tight and rigid reaction rims. The reaction rim allows the penetration of alkaline solution but prevents the leakage of viscous alkali silicate, so that alkali silicate generated afterward is accumulated in the aggregate to give an expansive pressure enough for cracking the aggregate and the surrounding concrete. The effect of nuclear radiation on the reactivity of quartz and plagioclase, a part of major minerals composing volcanic rocks as popular aggregates, to alkaline solution has been examined for clarifying whether nuclear radiations accelerates the ASR. It has been found that the irradiation of these minerals converts them into alkali-reactive amorphous ones. The radiation dose for plagioclase is as low as 108 Gy, which suggests that the ASR of concrete surrounding nuclear reactors is possible to be accelerated by nuclear radiation. (author)

  4. Phytochemicals for prevention of solar ultraviolet radiation-induced damages.

    Science.gov (United States)

    Adhami, Vaqar M; Syed, Deeba N; Khan, Naghma; Afaq, Farrukh

    2008-01-01

    While solar light is indispensable for sustenance of life, excessive exposure can cause several skin-related disorders. The UV part of solar radiation, in particular, is linked to disorders ranging from mild inflammatory effects of the skin to as serious as causing several different types of cancers. Changes in lifestyle together with depletion in the atmospheric ozone layer during the last few decades have led to an increase in the incidence of skin cancer. Skin cancers consisting of basal and squamous cell carcinomas are especially linked to the UVB part of solar radiation. Reducing excessive exposure to solar radiation is desirable; however, as this approach is unavoidable, it is suggested that other novel strategies be developed to reduce the effects of solar radiation to skin. One approach to reduce the harmful effects of solar radiation is through the use of phytochemicals, an approach that is popularly known as "Photochemoprotection." In recent years many phytochemicals with potential antioxidant properties have been identified and found to be photoprotective in nature. We describe here some of the most popular phytochemicals being studied that have the potential to reduce the harmful effects associated with solar UV radiation. PMID:18266816

  5. Comparative study of radiation damage accumulation in Cu and Fe

    Science.gov (United States)

    Caturla, M. J.; Soneda, N.; Alonso, E.; Wirth, B. D.; Díaz de la Rubia, T.; Perlado, J. M.

    2000-01-01

    Bcc and fcc metals exhibit significant differences in behavior when exposed to neutron or heavy ion irradiation. Transmission electron microscopy (TEM) observations reveal that damage in the form of stacking fault tetrahedra (SFT) is visible in copper irradiated to very low doses, but that no damage is visible in iron irradiated to the same total dose. In order to understand and quantify this difference in behavior, we have simulated damage production and accumulation in fcc Cu and bcc Fe. We use 20 keV primary knock-on atoms (PKAs) at a homologous temperature of 0.25 of the melting point. The primary damage state was calculated using molecular dynamics (MD) with empirical, embedded-atom interatomic potentials. Damage accumulation was modeled using a kinetic Monte Carlo (kMC) algorithm to follow the evolution of all defects produced in the cascades. The diffusivities and binding energies of defects are input data for this simulation and were either extracted from experiments, the literature, or calculated using MD. MD simulations reveal that vacancy clusters are produced within the cascade core in the case of copper. In iron, most of the vacancies do not cluster during cooling of the cascade core and are available for diffusion. In addition, self-interstitial atom (SIA) clusters are produced in copper cascades but those observed in iron are smaller in number and size. The combined MD/kMC simulations reveal that the visible cluster densities obtained as a function of dose are at least one order of magnitude lower in Fe than in Cu. We compare the results with experimental measurements of cluster density and find excellent agreement between the simulations and experiments when small interstitial clusters are considered to be mobile as suggested by recent MD simulations.

  6. Primary and secondary damage to biological tissue induced by laser radiation

    International Nuclear Information System (INIS)

    A simply analytic model describing the evolution of the thermal injury during and after exposure of biological tissue to pulses of intense laser radiation is presented. Estimates for the upper and lower bounds of the extent of the thermal injury associated with protein and enzyme denaturization (secondary damage) relative to the extent of burned tissue (primary damage) are presented. The energy necessary for burn threshold and the energy required to induce both types of thermal injury increase with laser pulse duration. An optimal duration of laser pulse exists at which the extent of the secondary damage relative to the primary damage is the smallest

  7. Radiation damage calculation by NPRIM computer code with JENDL3.3

    International Nuclear Information System (INIS)

    The Neutron Damage Evaluation Group of the Atomic Energy Society of Japan starts an identification of neutron-induced radiation damage in materials for typical neutron fields. For this study, a computer code, NPRIM, has been developed to be free from a tedious computational effort, which has been devoted to the calculation of derived quantities such as dpa and helium production rate. Neutron cross sections concerning to damage reactions based on JENDL3.3 are given with 640-group-structure. The impact of cross sections based on JENDL3.3 to damage calculation results has been described in this paper. (author)

  8. Non-randomized mtDNA damage after ionizing radiation via charge transport

    OpenAIRE

    Xin Zhou; Xinguo Liu; Xin Zhang; Rong Zhou; Yang He; Qiang Li; Zhenhua Wang; Hong Zhang

    2012-01-01

    Although it is well known that there are mutation hot spots in mtDNA, whether there are damage hot spots remain elusive. In this study, the regional DNA damage of mitochondrial genome after ionizing radiation was determined by real-time quantitative PCR. The mtDNA damage level was found to be dose-dependent and regional unequal. The control region was the most susceptible region to oxidative damage. GGG, as an typical hole trap during charge transport, was found to be disproportionally enrich...

  9. The Fifth International Ural seminar. Radiation damage physics of metals and alloys. Abstracts

    International Nuclear Information System (INIS)

    Presented are the abstracts of The Fifth International Ural seminar Damage physics of metals and alloys. General problems of radiation damage physics, radiation effect on change of microstucture and the properties of metals and alloys, as well as materials for nuclear and thermonuclear energetics are considered. The themes of reports are the following: correlation effects in cascades of atom-atomic collisions; radiation-induced strengthening critical current density in YBa2Cu3O7-x superconductors; conditions of forming and hydrides growth in irradiated zirconium alloys

  10. Protective effect of deoxynucleotide triphosphates on DNA damage in different mammalian cells exposed to -radiation

    Directory of Open Access Journals (Sweden)

    Elmaghraby, T

    2002-09-01

    Full Text Available DNA is generally considered to be the most critical cellular target when considering the lethal, carcinogenic and mutagenic effects of drugs, radiation and environmental chemicals. So the study aim to the determination the damaging effect of -radiation on DNA and the protective effect of deoxynucleotide triphosphates (dNTPs. The study includes three cell types, lymphocytes, kidney cells of African gree monkey (Vero and hepatocellular carcinoma of human (HePG2 exposed to 1-5 Gy of -radiation and by using fluorometric analysis of DNA unwinding (FADU method, DNA damage was measured after radiation. The cells were divided into two groups: The first received 5x10-5 dNTPs from 0-30 minutes after radiation, while the second group was not supplemented with deoxynucleotides. Clonogenic survival for vero and HePG2 cell lines was measured. The results revealed that the increase of irradiation dose precipitates an increase of DNA strand breaks. The slope curve of initial DNA damage and mean inactivation dose (D differ between vero and HepG2 cell line by a factor of up 3.5 and 2, respectively. dNTPs have clear ameliorating effect on DNA damage. FADU method can play an important role in the choice of a suitable treatment (radiation or drugs and its dosage according to measurement of DNA damages in selective malignant tissues. Moreover, using dNTPs mixture can reduce the side effect of these treatment especially after experimentally on live mammals (mice .

  11. Spatiotemporal characterization of ionizing radiation induced DNA damage foci and their relation to chromatin organization

    OpenAIRE

    Costes, S.V.; Chiolo, I.; Pluth, J.M.; Barcellos-Hoff, M. H.; Jakob, B.

    2010-01-01

    DNA damage sensing proteins have been shown to localize to the sites of DNA double strand breaks (DSB) within seconds to minutes following ionizing radiation (IR) exposure, resulting in the formation of microscopically visible nuclear domains referred to as radiation-induced foci (RIF). This review characterizes the spatiotemporal properties of RIF at physiological doses, minutes to hours following exposure to ionizing radiation, and it proposes a model describing RIF formation and resolution...

  12. \\title{Development of Radiation Damage Models for Irradiated Silicon Sensors Using TCAD Tools}

    CERN Document Server

    Bhardwaj, Ashutosh; Lalwani, Kavita; Ranjan, Kirti; Printz, Martin; Ranjeet, Ranjeet; Eber, Robert; Eichhorn, Thomas; Peltola, Timo Hannu Tapani

    2014-01-01

    Abstract. During the high luminosity upgrade of the LHC (HL-LHC) the CMS tracking system will face a more intense radiation environment than the present system was designed for. In order to design radiation tolerant silicon sensors for the future CMS tracker upgrade it is fundamental to complement the measurement with device simulation. This will help in both the understanding of the device performance and in the optimization of the design parameters. One of the important ingredients of the device simulation is to develop a radiation damage model incorporating both bulk and surface damage. In this paper we will discuss the development of a radiation damage model by using commercial TCAD packages (Silvaco and Synopsys), which successfully reproduce the recent measurements like leakage current, depletion voltage, interstrip capacitance and interstrip resistance, and provides an insight into the performance of irradiated silicon strip sensors.

  13. Silibinin attenuates ionizing radiation-induced pro-angiogenic response and EMT in prostate cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Nambiar, Dhanya K. [Cancer Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi (India); School of Environmental Sciences, Jawaharlal Nehru University, New Delhi (India); Rajamani, Paulraj [School of Environmental Sciences, Jawaharlal Nehru University, New Delhi (India); Singh, Rana P., E-mail: rana_singh@mail.jnu.ac.in [Cancer Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi (India); School of Life Sciences, Central University of Gujarat, Gandhinagar (India)

    2015-01-02

    Graphical abstract: Potential model showing mechanism of silibinin-mediated attenuation of IR-induced angiogenic phenotype and EMT in tumor cells. Silibinin counters radiation induced invasive and migratory phenotype of cancer cells by down-regulating mitogenic pathways activated by IR, leading to inhibition of molecules including VEGF, iNOS, MMPs and N-cadherin. Silibinin also reverses IR mediated E-cadherin down-regulation, inhibiting EMT in tumor cells. Silibinin also radiosensitizes endothelial cells, reduces capillary tube formation by targeting various pro-angiogenic molecules. Further, silibinin may inhibit autocrine and paracrine signaling between tumor and endothelial cells by decreasing the levels of VEGF and other signaling molecules activated in response to IR. - Highlights: • Silibinin radiosensitizes endothelial cells. • Silibinin targets ionization radiation (IR)-induced EMT in PCa cells. • Silibinin is in phase II clinical trial in PCa patients, hence clinically relevant. - Abstract: Radiotherapy of is well established and frequently utilized in prostate cancer (PCa) patients. However, recurrence following therapy and distant metastases are commonly encountered problems. Previous studies underline that, in addition to its therapeutic effects, ionizing radiation (IR) increases the vascularity and invasiveness of surviving radioresistant cancer cells. This invasive phenotype of radioresistant cells is an upshot of IR-induced pro-survival and mitogenic signaling in cancer as well as endothelial cells. Here, we demonstrate that a plant flavonoid, silibinin can radiosensitize endothelial cells by inhibiting expression of pro-angiogenic factors. Combining silibinin with IR not only strongly down-regulated endothelial cell proliferation, clonogenicity and tube formation ability rather it strongly (p < 0.001) reduced migratory and invasive properties of PCa cells which were otherwise marginally affected by IR treatment alone. Most of the pro

  14. Silibinin attenuates ionizing radiation-induced pro-angiogenic response and EMT in prostate cancer cells

    International Nuclear Information System (INIS)

    Graphical abstract: Potential model showing mechanism of silibinin-mediated attenuation of IR-induced angiogenic phenotype and EMT in tumor cells. Silibinin counters radiation induced invasive and migratory phenotype of cancer cells by down-regulating mitogenic pathways activated by IR, leading to inhibition of molecules including VEGF, iNOS, MMPs and N-cadherin. Silibinin also reverses IR mediated E-cadherin down-regulation, inhibiting EMT in tumor cells. Silibinin also radiosensitizes endothelial cells, reduces capillary tube formation by targeting various pro-angiogenic molecules. Further, silibinin may inhibit autocrine and paracrine signaling between tumor and endothelial cells by decreasing the levels of VEGF and other signaling molecules activated in response to IR. - Highlights: • Silibinin radiosensitizes endothelial cells. • Silibinin targets ionization radiation (IR)-induced EMT in PCa cells. • Silibinin is in phase II clinical trial in PCa patients, hence clinically relevant. - Abstract: Radiotherapy of is well established and frequently utilized in prostate cancer (PCa) patients. However, recurrence following therapy and distant metastases are commonly encountered problems. Previous studies underline that, in addition to its therapeutic effects, ionizing radiation (IR) increases the vascularity and invasiveness of surviving radioresistant cancer cells. This invasive phenotype of radioresistant cells is an upshot of IR-induced pro-survival and mitogenic signaling in cancer as well as endothelial cells. Here, we demonstrate that a plant flavonoid, silibinin can radiosensitize endothelial cells by inhibiting expression of pro-angiogenic factors. Combining silibinin with IR not only strongly down-regulated endothelial cell proliferation, clonogenicity and tube formation ability rather it strongly (p < 0.001) reduced migratory and invasive properties of PCa cells which were otherwise marginally affected by IR treatment alone. Most of the pro

  15. Role of membrane and cellular oxidative damage in gamma radiation induced apoptotic death in mouse thymocytes

    International Nuclear Information System (INIS)

    Full text: Involvement of plasma membrane in the molecular mechanism of radiation-induced apoptotic death has increasingly been recognized by radiobiologists in the recent years. In present investigation, alterations in plasma membrane and the associated cytoplasmic / nuclear events were studied in apoptotic mouse thymocytes after gamma radiation exposure. The membrane oxidative damage in irradiated thymocytes was determined by thiobarbituric acid reactive species (TBARS) method and change in membrane permeability was estimated employing fluorescein diacetate (FDA) as fluorescent probe. Radiation-induced apoptotic thymocytes showed an increase in membrane permeability as observed by leakage of FDA, while trypan blue failed to respond. Moreover, using fluorescence technique, the changes in thymocytes membrane permeability could be sensitively determined within low to moderate radiation doses (2 cGy to 2 Gy). The dose dependent increase in intra-cellular reactive oxygen species (ROS) generation was found in irradiated thymocytes determined by fluorescence method, which could sensitively detect the radiation exposure in sub cGy range. Radiation induced membrane changes were found correlated with induction of apoptotic death determined by annexin-V method, caspase-3 assay, measuring nuclear diameter using propidium iodide (PI) staining and DNA fragmentation by gel electrophoresis. It has been also shown that membrane associated events observed in radiation induced apoptotic thymocytes are prior to nuclear / cytosolic processes. The membrane lipid peroxidation, cellular oxidative damage and apoptosis in radiation treated thymocytes were significantly inhibited by membrane-localized antioxidants suggesting significant contribution of membrane damage and oxidative stress in radiation mediated apoptosis in thymocytes

  16. Diffraction data analysis in the presence of radiation damage

    International Nuclear Information System (INIS)

    Radiation-induced decay of crystal diffraction and additional specific chemical changes of macromolecules forming the crystal lattice are currently two of the main limiting factors in the acquisition of macromolecular diffraction data and macromolecular structure determination. Data-processing and phasing protocols are discussed in the context of radiation-induced changes. In macromolecular crystallography, the acquisition of a complete set of diffraction intensities typically involves a high cumulative dose of X-ray radiation. In the process of data acquisition, the irradiated crystal lattice undergoes a broad range of chemical and physical changes. These result in the gradual decay of diffraction intensities, accompanied by changes in the macroscopic organization of crystal lattice order and by localized changes in electron density that, owing to complex radiation chemistry, are specific for a particular macromolecule. The decay of diffraction intensities is a well defined physical process that is fully correctable during scaling and merging analysis and therefore, while limiting the amount of diffraction, it has no other impact on phasing procedures. Specific chemical changes, which are variable even between different crystal forms of the same macromolecule, are more difficult to predict, describe and correct in data. Appearing during the process of data collection, they result in gradual changes in structure factors and therefore have profound consequences in phasing procedures. Examples of various combinations of radiation-induced changes are presented and various considerations pertinent to the determination of the best strategies for handling diffraction data analysis in representative situations are discussed

  17. Effects of different levels of vitamin C on UV radiation-induced DNA damage

    Institute of Scientific and Technical Information of China (English)

    Dianfeng Zhou; Hang Heng; Kang Ji; Weizhong Ke

    2005-01-01

    The Raman spectra of DNA in different levels of vitamin C with 10- and 30-min ultraviolet (UV) radiations were reported. The intensity of UV radiation was 18.68 W/m2. The experimental results proved that vitamin C could alone prevent UV radiation from damaging DNA, but the effects depended on the concentration of vitamin C. When the concentration of vitamin C was about 0.08-0.4 mmol/L, vitamin C decreased UV radiation-induced DNA's damage. When the concentration of vitamin C exceeded 0.4 mmol/L, vitamin C accelerated DNA's damage instead. Maybe the reason is that when DNA in aqueous solution is radiated by UV, free radicals come into being, and vitamin C can scavenge free radicals, so vitamin C in lower concentration can protect DNA. The quantity of free radicals is finite, when vitamin C is superfluous, free radicals have been scavenged absolutely and vitamin C is residual. Vitamin C is a strong reductant. When the mixture of DNA and residual vitamin C is radiated by UV, vitamin C reacts with DNA. The more residual vitamin C and the longer time of UV radiation, the more DNA is damaged.

  18. Efficacy of serotonin in lessening radiation damage to mouse embryo depending on time of its administration following radiation exposure

    International Nuclear Information System (INIS)

    Our earlier studies demonstrated that serotonin lessons radiation damage to an 8-day mouse embryo. Moreover, this biogenic amine was equally effective when administered before and after intrauterine exposure of the embryo to ionizing radiation. The radiotherapeutic effect of serotonin was manifested by disorders in the embryo growth of various intensity, within the range of the studied radiation doses (1.31, 1.74, and 2.18 Gy). The therapeutic effect of serotonin in the embryos exposed to various doses of radiation depended on the amount of serotonin administered. The effective doses of this substance were determined by the severity of the damage inflicted. In this series of experiments, serotonin was administered immediately after exposure to ionizing radiation. The object of the present study was to determine whether or not the radiotherapeutic effect of serotonin depends on the time that elapses between the end of radiation exposure and the administration of serotonin to pregnant mice. It was established that serotonin produces a radiotherapeutic effect during 24 h following the intrauterine exposure of the fetus to ionizing radiation on the 8th day of gestation. The best therapeutic effect is attained with the administration of serotonin immediately after radiation exposure. The effect is slightly lower is serotonin is administered within 5 or 24 h following radiation exposure

  19. The superconducting critical temperature of radiation damaged A-15 compounds

    International Nuclear Information System (INIS)

    A simple model is used to explain the decrease in superconducting critical temperature with damage observed for irradiated A-15 compounds. A truncated t-matrix approximation is used to describe the disorder along the one-dimensional transition metal chains. Three dimensionality is introduced by the inclusion of interaction between transition metal atoms on different chains. Numerical fits to experiment are discussed in the conclusion. (author)

  20. BGO radiation damage effects optical absorption, thermoluminescence and thermoconductivity

    CERN Document Server

    Lecoq, P; Rostaing, B

    1991-01-01

    After irradiation, the light transmission of bismuth germanate monocrystals decreases, mainly in the blue, as a consequence of the formation of colour centres. The absorption, thermoluminescence and thermoconductivity spectra were studied for different kinds of irradiation, different doses and at different temperatures. Doped samples were also tested, showing the role of impurities, mainly iron, in the process of damage. Finally a model is proposed which explains all the experimental results.

  1. Radiation damage in UO2 by swift heavy ions

    International Nuclear Information System (INIS)

    Specimens of sintered UO2, a high melting point ceramic with the fluorite structure, were irradiated with heavy ions (129Xe, 238U) with different fluences (5 x 1010 to 7 x 1013 ions/cm2) and energies (173 MeV for Xe ions to 2.713 GeV for U ions). The influence of the electronic energy loss on the mechanisms of damage formation was studied in the range of 29 to 60 keV/nm. Transmission Electron Microscopy (TEM) was performed to identify and characterize the damage induced by these ions. Tracks produced by U ions of 2713 and 1300 MeV and by Xe ions of 173 MeV were observed. The radii of the observed tracks were calculated using a thermal-spike model, taking into account the thermodynamic parameters of the material and the energy and velocity of the incoming ions. The TRIM code was used to determine the displacement profile and the energy distribution along the ion paths. Good agreement with the experimental results was found. The dependence of damage formation on the ion dose was also studied. For instance, defect clusters and loops were produced in UO2 irradiated with 129Xe of 173 MeV (dE/dx∝29 keV/nm) between 7 x 1010 and 7 x 1013 ions/cm2. (orig.)

  2. Experimental studies of radiation damage of silicon detectors

    International Nuclear Information System (INIS)

    New particle physics experiments are correlated with high luminosity and/or high energy. The new generation of colliding beam machines which will be constructed will make an extrapolation of a factor of 100 in the center of mass energy and of 1000 in luminosity beyond present accelerators. The scientific community hopes that very exciting physics results could be achieved this way, from the solution to the problem of electroweak symmetry breaking to the possible discovery of new, unpredicted phenomena. The particles which compose the radiation field are: electrons, pions, neutrons, protons and photons. It has become evident that the problem of the radiation resistance of detectors in this severe environment is a crucial one. This situation is complicated more by the fact that detectors must work all the run time of the machine, and better all the time of the experiment, without replacement (part or whole). So, studies related to the investigation of the radiation hardness of all detector parts, are developing. The studies are in part material and device characterization after irradiation, and in part technological developments, made in order to find harder, cheaper technologies, for larger surfaces. Semiconductor detectors have proven to be a good choice for vertex and calorimeter. Both fixed target machines and colliders had utilized in the past silicon junction detectors as the whole or part of the detection system. Precision beam hodoscopes and sophisticated trigger devices with silicon are equally used. The associated electronics in located near the detectors, and is subjected to the same radiation fields. Studies of material and device radiation hardness are developing in parallel. Here the authors present results on the radiation hardness of silicon, both as a bulk material and as detectors, to neutron irradiation at high fluences

  3. Spectral attenuation of solar radiation in Patagonian fjord and coastal waters and implications for algal photobiology

    Science.gov (United States)

    Huovinen, Pirjo; Gómez, Iván

    2011-03-01

    The spectral attenuation of solar irradiation was measured during summer in two types of coastal waters in southern Chile, a north Patagonian fjord (Seno Reloncaví) and open coast (Valdivia). In order to relate the light availability with the light requirements of upper subtidal seaweeds, the saturating irradiance for photosynthesis ( Ek) from P- I curves was measured. In addition the UV risk was assessed. Based on the z1% of PAR, the lower limit of the euphotic zone in the studied systems averaged 21 m ( Kd 0.24 m -1) in Seno Reloncaví and 18 m ( Kd 0.27 m -1) in the coast of Valdivia. Photosynthesis of the studied seaweeds was saturated at markedly lower irradiances than found in their natural depths at the time of the study. Solar radiation penetrating into these depths at both locations largely supports the light requirements for the photosynthesis of subtidal species: 50-160 μmol m -2 s -1 for seaweeds from Seno Reloncaví (7 m tidal range) and 20-115 μmol m -2 s -1 for Valdivia assemblages (2 m tidal range). Optimal light conditions to saturate photosynthesis ( Ek) were present at 10-16 m water depth. The attenuation of solar irradiation did not vary significantly between the fjord and coastal sites of this study. However, the underwater light climates to which seaweeds are exposed in these sites vary significantly because of the stronger influence of tidal range affecting the fjord system as compared with the open coastal site. The patterns of UV-B penetration in these water bodies suggest that seaweeds living in upper littoral zones such as the intertidal and shallow subtidal (<3 m) may be at risk.

  4. The Effect of Various Waste Materials’ Contents on the Attenuation Level of Anti-Radiation Shielding Concrete

    Directory of Open Access Journals (Sweden)

    Rafiza Abdul Razak

    2013-10-01

    Full Text Available Samples of concrete contain various waste materials, such as iron particulates, steel balls of used ball bearings and slags from steel industry were assessed for their anti-radiation attenuation coefficient properties. The attenuation measurements were performed using gamma spectrometer of NaI (Tl detector. The utilized radiation sources comprised 137Cs and 60Co radioactive elements with photon energies of 0.662 MeV for 137Cs and two energy levels of 1.17 and 1.33 MeV for the 60Co. Likewise the mean free paths for the tested samples were obtained. The aim of this work is to investigate the effect of the waste loading rates and the particulate dispersive manner within the concrete matrix on the attenuation coefficients. The maximum linear attenuation coefficient (μ was attained for concrete incorporates iron filling wastes of 30 wt %. They were of 1.12 ± 1.31×10−3 for 137Cs and 0.92 ± 1.57 × 10−3 for 60Co. Substantial improvement in attenuation performance by 20%–25% was achieved for concrete samples incorporate iron fillings as opposed to that of steel ball samples at different (5%–30% loading rates. The steel balls and the steel slags gave much inferior values. The microstructure, concrete-metal composite density, the homogeneity and particulate dispersion were examined and evaluated using different metallographic, microscopic and measurement facilities.

  5. TEM observations of radiation damage in tungsten irradiated by 20 MeV W ions

    Energy Technology Data Exchange (ETDEWEB)

    Ciupiński, Ł., E-mail: lciupinski@gmail.com [Warsaw University of Technology, ul. Woloska 141, PL-02507 Warsaw (Poland); Ogorodnikova, O.V. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany); Płociński, T.; Andrzejczuk, M.; Rasiński, M. [Warsaw University of Technology, ul. Woloska 141, PL-02507 Warsaw (Poland); Mayer, M. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany); Kurzydłowski, K.J. [Warsaw University of Technology, ul. Woloska 141, PL-02507 Warsaw (Poland)

    2013-12-15

    Polycrystalline, recrystallized W targets were subjected to implantation with 20 MeV W{sup 6+} ions in order to simulate radiation damage caused by fusion neutrons. Three samples with cumulative damage of 0.01, 0.1 and 0.89 dpa were produced. The near-surface zone of each sample has been analyzed by transmission electron microscopy (TEM). To this end, lamellae oriented perpendicularly to the targets implanted surface were milled out using focused ion beam (FIB). A reference lamella from non-irradiated, recrystallized W target was also prepared to estimate the damage introduced during FIB processing. TEM studies revealed a complex microstructure of the damaged zones as well as its evolution with cumulative damage level. The experimentally observed damage depth agrees very well with the one calculated using the Stopping and Range of Ions in Matter (SRIM) software.

  6. Beclin 1 and UVRAG confer protection from radiation-induced DNA damage and maintain centrosome stability in colorectal cancer cells.

    Directory of Open Access Journals (Sweden)

    Jae Myung Park

    Full Text Available Beclin 1 interacts with UV-irradiation-resistance-associated gene (UVRAG to form core complexes that induce autophagy. While cells with defective autophagy are prone to genomic instability that contributes to tumorigenesis, it is unknown whether Beclin1 or UVRAG can regulate the DNA damage/repair response to cancer treatment in established tumor cells. We found that siRNA knockdown of Beclin 1 or UVRAG can increase radiation-induced DNA double strand breaks (DSBs, shown by pATM and γH2Ax, and promote colorectal cancer cell death. Furthermore, knockdown of Beclin 1, UVRAG or ATG5 increased the percentage of irradiated cells with nuclear foci expressing 53BP1, a marker of nonhomologous end joining but not RAD51 (homologous recombination, compared to control siRNA. Beclin 1 siRNA was shown to attenuate UVRAG expression. Cells with a UVRAG deletion mutant defective in Beclin 1 binding showed increased radiation-induced DSBs and cell death compared to cells with ectopic wild-type UVRAG. Knockdown of Beclin 1 or UVRAG, but not ATG5, resulted in a significant increase in centrosome number (γ-tubulin staining in irradiated cells compared to control siRNA. Taken together, these data indicate that Beclin 1 and UVRAG confer protection against radiation-induced DNA DSBs and may maintain centrosome stability in established tumor cells.

  7. Radiation damage to DNA in DNA-protein complexes

    Czech Academy of Sciences Publication Activity Database

    Spotheim Maurizot, M.; Davídková, Marie

    2011-01-01

    Roč. 711, 1-2 (2011), s. 41-48. ISSN 0027-5107 Institutional research plan: CEZ:AV0Z10480505 Keywords : DNA-protein complex * ionizing radiation * molecular structure Subject RIV: BO - Biophysics Impact factor: 2.850, year: 2011

  8. Feasibility of OCT to detect radiation-induced esophageal damage in small animal models (Conference Presentation)

    Science.gov (United States)

    Jelvehgaran, Pouya; Alderliesten, Tanja; Salguero, Javier; Borst, Gerben; Song, Ji-Ying; van Leeuwen, Ton G.; de Boer, Johannes F.; de Bruin, Daniel M.; van Herk, Marcel B.

    2016-03-01

    Lung cancer survival is poor and radiotherapy patients often suffer serious treatment side effects. The esophagus is particularly sensitive leading to reduced food intake or even fistula formation. Only few direct techniques exist to measure radiation-induced esophageal damage, for which knowledge is needed to improve the balance between risk of tumor recurrence and complications. Optical coherence tomography (OCT) is a minimally-invasive imaging technique that obtains cross-sectional, high-resolution (1-10µm) images and is capable of scanning the esophageal wall up to 2-3mm depth. In this study we investigated the feasibility of OCT to detect esophageal radiation damage in mice. In total 30 mice were included in 4 study groups (1 main and 3 control groups). Mice underwent cone-beam CT imaging for initial setup assessment and dose planning followed by single-fraction dose delivery of 4, 10, 16, and 20Gy on 5mm spots, spaced 10mm apart. Mice were repeatedly imaged using OCT: pre-irradiation and up to 3 months post-irradiation. The control groups received either OCT only, irradiation only, or were sham-operated. We used histopathology as gold standard for radiation-induced damage diagnosis. The study showed edema in both the main and OCT-only groups. Furthermore, radiation-induced damage was primarily found in the highest dose region (distal esophagus). Based on the histopathology reports we were able to identify the radiation-induced damage in the OCT images as a change in tissue scattering related to the type of induced damage. This finding indicates the feasibility and thereby the potentially promising role of OCT in radiation-induced esophageal damage assessment.

  9. Fundamental experimentation of radiation damage to spinal cords in infantile mice

    International Nuclear Information System (INIS)

    In the multi-modal therapy, normal tissue damage is the limiting factor in the radiotherapy of cancer. Intraoperative irradiation resolves this problem by shielding critical organs. In the treatment of pediatric malignancies located in the abdomen, however, the spinal cord is inevitably irradiated. We here investigated and report effects of radiation damage to spinal cord of infantile mice. Materials and methods : Four week-old C3Hf/He male mice, weighing 21 ∼ 24 g, were used throughout experiments. Lumbar cord of spine (L1 ∼ L5) was irradiated with single fraction of X ray machine (20 mA, 25 cm FSD, 322 rad/min). Changes of neurological status after irradiation were scored by observing movements of mice. The scoring method has been employed by Goffinet, et al. Results : In the first place, we investigated the relationship between radiation dose and body weight gaining. Irradiation with large doses perturbed growth of infantile mice. The latent period between radiation and onset of paralysis in infantile mice was shorter than that in adult mice. In addition severe damage of spinal cord was observed in infantile mice by 30 ∼ 50 Gy. By the same dosage, mild damage was reported in adult mice. With 22 Gy, however, radiation did not result apparent damage. It is suggested that careful attention should be paid to radiation of spinal cord in young children. (author)

  10. Radiation induced damage to the lipid contents of bacteria and cultured mammalian cells

    International Nuclear Information System (INIS)

    In this study, exponentially growing phase of E. Coli. K12-N167 and cultured mouse leukemic L5178Y were used to study the effect of gamma irradiation on phospholipid contents. Following irradiation, both bacteria and cultured cells were incubated with either 14C or 32P labelled precursors for periods of cell division time. Phospholipid composition and their contents were detected in both the bacteria and cultured cells by using liquid scintillation counting and autoradiography methods. In contrast, as radiation dose increased, the Phospholipid contents were decreased in the both bacteria and cultured cells. It was concluded that the changes of phospholipid contents may result to altered activities of phospholipid pathway enzymes damaged by a radiation dose. The results of this investigation would be helpful in control of induced radiation damages in cell killings in radiation workers and radiation treatment of human cancer in the clinics. (author). 35 refs, 3 figs, 4 tabs

  11. Compensation for damage to workers health exposed to ionizing radiation in Argentina

    CERN Document Server

    Sobehart, L J

    2003-01-01

    The objective of this report is to analyze the possibility to establish a scheme to compensate damage to workers health exposed to ionizing radiation in Argentina for those cases in which it is possible to assume that the exposure to ionizing radiation is the cause of the cancer suffered by the worker. The proposed scheme is based on the recommendations set out in the 'International Conference on Occupational Radiation Protection: Protecting Workers against Exposure to Ionization Radiation, held in Geneva, Switzerland, August 26-30, 2002. To this end, the study analyzes the present state of scientific knowledge on cancer causation due to genotoxic factors, and the accepted form of the doses-response curve, for the human beings exposure to ionization radiation at low doses with low doses rates. Finally, the labor laws and regulations related to damage compensation; in particular the present Argentine Labor Law; the National Russian Federal Occupational Radiological Health Impairment and Workmen Compensation, t...

  12. Umbelliferone suppresses radiation induced DNA damage and apoptosis in hematopoietic cells of mice

    International Nuclear Information System (INIS)

    Radiotherapy is one of the major modes of treatment for different types of cancers. But the success of radiotherapy is limited by injury to the normal cells. Protection of the normal cells from radiation damage by radioprotectors can increase therapeutic efficiency. These radioprotectors can also be used during nuclear emergency situations. Umbelliferone (UMB) is a wide spread natural product of the coumarin family. It occurs in many plants from the Apiaceae family. In the present study radioprotective effect of UMB was investigated in vitro and in vivo. Anti genotoxic effect of Umbelliferone was tested by treating the splenic lymphocytes with various doses of UMB (6.5 μM - 50 μM) prior to radiation (6Gy) exposure. After the radiation exposure, extent of DNA damage was assessed by comet assay at 5 mm and two hours after radiation exposure. At both the time points, it was observed that the pretreatment of UMB reduced the radiation induced DNA damage to a significant extent in comparison to radiation control. UMB pretreatment also significantly reduced the radiation induced apoptosis enumerated by propidium iodide staining assay. Results of clonogenic survival assay using intestinal cell line showed that pretreatment with UMB significantly protected against radiation induced loss of colony forming units. To assess the anti genotoxic role of umbelliferone in vivo two different doses of UMB (20 mg/Kg and 40 mg/Kg of body weight) were injected into Swiss mice or with vehicle and exposed to radiation. Thirty minutes after the radiation comet assay was performed in peripheral leukocytes. Frequency of micro nucleated erythrocytes was scored in bone marrow cells. It was observed that UMB alone did not cause any significant increase in DNA damage in comparison to control. Animals which are exposed to radiation alone showed significant increase in DNA damage and micronuclei frequency. But animals treated with UMB prior to the radiation exposure showed significant decrease

  13. Fluorescence studies on radiation oxidative damage to membranes with implications to cellular radiosensitivity

    International Nuclear Information System (INIS)

    Radiation oxidative damage to plasma membrane and its consequences to cellular radiosensitivity have received increasing attention in the past few years. This review gives a brief account of radiation oxidative damage in model and cellular membranes with particular emphasis on results from our laboratory. Fluorescence and ESR spin probes have been employed to investigate the structural and functional alterations in membranes after γ-irradiation. Changes in the lipid bilayer in irradiated unilamellar liposomes prepared from egg yolk lecithin (EYL) were measured by using diphenylhexatriene (DPH) as a probe. The observed increase in DPH polarization and decrease in fluorescence intensity after γ-irradiation of liposomes imply radiation-induced decrease in bilayer fluidity. Inclusion of cholesterol in liposome was found to protect lipids against radiation damage, possibly by modulation of bilayer organization e.g. lipid packing. Measurements on dipalmitoyl phosphatidylcholine (DPPC) liposomes loaded with 6-carboxyfluorescein (CF) showed radiation dose-dependent release of the probe indicating radiation-induced increased permeability. Changes in plasma membrane permeability of thymocytes were monitored by fluorescein diacetate (FDA) and induced intracellular reactive oxygen species (ROS) were determined by 2,7-dichlorodihydro fluorescein diacetate (DCH-FDA). Results suggest a correlation between ROS generation and membrane permeability changes induced by radiation within therapeutic doses (0-10 Gy). It is concluded that increase in membrane permeability was the result of ROS-mediated oxidative reactions which might trigger processes leading to apoptotic cell death after radiation exposure. (author)

  14. Radiation Damage Studies on a Laser Fusion Reactor

    International Nuclear Information System (INIS)

    Full text: A laser fusion-fission (hybrid) has been investigated with a multi-layered spherical blanket, composed of a first wall made of oxide dispersed steel (ODS, 2 cm); neutron multiplier and coolant zone made of LiPb; ODS-separator (2 cm); a molten salt Flibe coolant and fission zone; ODS-separator (2 cm); graphite reflector. In the second phase, LiPb coolant zone behind the first wall has been removed. But instead, a flowing liquid protective first wall is included of in front of the solid first wall in order to reduce material damage and residual radioactivity after final disposal of the latter. Tritium breeding ratio (TBR) has been calculated as TBR > 1.05 over 8 to 9 years of continuous plant operation period, which would supply fusion fuel for self-sustaining fusion reactor operation. Blanket energy multiplication factor (M) remains nearly stable between 2.4 to 6.8 over 10 years for TRISO fractions 2 to 8 vol-% in the coolant. Without an internal liquid wall protection, major damage mechanisms have been calculated as DPA = 50 and He = 170 appm/year at the ODS first wall. It faces directly to the fusion chamber, and will be the primary component subject to material damage. This will oblige to change the ODS first wall every ∼ 3 years. Hydrogen production is calculated as 650 appm/year. Hydrogen will not reside permanently in the metallic lattice as helium atoms, but diffuse out of the structure by high operation temperatures. The alternative version to include a Flibe zone of ∼ 50 cm thickness as flowing wall liquid protection in front of the solid ODS first wall reduces material damage below permissible limits. It allows shallow burial of structure after final reactor decommissioning. Calculations have yielded very high burn up grades (> 400 000 MW.D/MT) for the fissionable RG-PuC/ThC fuel without fuel change, making the LIFE engine a sustainable power source. Peach Bottom experiments have shown that TRISO fuel particles can withstand burn ups of 740

  15. Ion irradiation: A tool to study radiation damage in minerals

    International Nuclear Information System (INIS)

    The impact of radioactivity (in particular recoils of heavy daughter nuclei upon emission of an alpha particle) may cause severe changes and damages to crystalline minerals, up to their complete amorphisation. Heavy-ion irradiation is used to investigate and quantify irradiation effects in orthosilicates and -phosphates. A new approach is discussed in the talk, namely, the irradiation of thin FIB foils whose thicknesses correspond to the penetration depth of the ions irradiated. Finally, examples are presented for how MeV helium irradiation is applied to study the so-called alpha haloes in rock-forming minerals. (author)

  16. Radial distribution of radiation damage with heavy ions

    International Nuclear Information System (INIS)

    Foils of 300 μm of an organic material (Makrofol E polycarbonate) were irradiated with 19F ions of 49.7 MeV and alpha tracers of 360 keV. The irradiated material was processed through successive chemical attacks to evaluate the evolution of the particle diameter. In the case of 19F, the typical behavior of differential zones in the nm region was observed. However, in the tracers produced by alpha particles the differential zones were still observed, although not very clear. This could suggest that thermal explosion, of low energies effect, is not sufficient to produce a complete 'mixture' of the material in the damaged region. (author)

  17. Radiation damage in silicon. Defect analysis and detector properties

    International Nuclear Information System (INIS)

    Silicon microstrip and pixel detectors are vital sensor-components as particle tracking detectors for present as well as future high-energy physics (HEP) experiments. All experiments at the large Hadron Collider (LHC) are equipped with such detectors. Also for experiments after the upgrade of the LHC (the so-called Super-LHC), with its ten times higher luminosity, or the planned International Linear Collider (ILC) silicon tracking detectors are forseen. Close to the interaction region these detectors have to face harsh radiation fields with intensities above the presently tolerable level. defect engineering of the used material, e. g. oxygen enrichment of high resistivity float zone silicon and growing of thin low resistivityepitaxial layers on Czochralski silicon substrates has been established to improve the radiation hardness of silicon sensors. This thesis focuses mainly on the investigation of radiation induced defects and their differences observed in various kinds of epitaxial silicon material. Comparisons with other materials like float zone or Czochralski silicon are added. Deep Level Transient Spectroscopy (DLTS) and Thermally Stimulated Current (TSC) measurements have been performed after γ-, electron-, proton- and neutron-irradiation. The differenced in the formation of vacancy and interstitial related defects as well as so-called clustered regions were investigated for various types of irradiation. In addition to the well known defects VOi, CiOi, CiCs, VP or V2 several other defect complexes have been found and investigated. Also the material dependence of the defect introduction rates and the defect annealing behavior has been studied by isothermal and isochronal annealing experiments. Especially the IO2 defect which is an indicator for the oxygen-dimer content of the material has been investigated in detail. On the basis of radiation induced defects like the bistable donor (BD) defect and a deep acceptor, a model has been introduced to describe the

  18. Radiation damage in silicon. Defect analysis and detector properties

    Energy Technology Data Exchange (ETDEWEB)

    Hoenniger, F.

    2008-01-15

    Silicon microstrip and pixel detectors are vital sensor-components as particle tracking detectors for present as well as future high-energy physics (HEP) experiments. All experiments at the large Hadron Collider (LHC) are equipped with such detectors. Also for experiments after the upgrade of the LHC (the so-called Super-LHC), with its ten times higher luminosity, or the planned International Linear Collider (ILC) silicon tracking detectors are forseen. Close to the interaction region these detectors have to face harsh radiation fields with intensities above the presently tolerable level. defect engineering of the used material, e. g. oxygen enrichment of high resistivity float zone silicon and growing of thin low resistivityepitaxial layers on Czochralski silicon substrates has been established to improve the radiation hardness of silicon sensors. This thesis focuses mainly on the investigation of radiation induced defects and their differences observed in various kinds of epitaxial silicon material. Comparisons with other materials like float zone or Czochralski silicon are added. Deep Level Transient Spectroscopy (DLTS) and Thermally Stimulated Current (TSC) measurements have been performed after {gamma}-, electron-, proton- and neutron-irradiation. The differenced in the formation of vacancy and interstitial related defects as well as so-called clustered regions were investigated for various types of irradiation. In addition to the well known defects VO{sub i}, C{sub i}O{sub i}, C{sub i}C{sub s}, VP or V{sub 2} several other defect complexes have been found and investigated. Also the material dependence of the defect introduction rates and the defect annealing behavior has been studied by isothermal and isochronal annealing experiments. Especially the IO{sub 2} defect which is an indicator for the oxygen-dimer content of the material has been investigated in detail. On the basis of radiation induced defects like the bistable donor (BD) defect and a deep

  19. Molecular dynamics simulation of radiation damage in bcc tungsten

    International Nuclear Information System (INIS)

    Molecular dynamics simulations of collision cascades in pure tungsten are performed to assess the primary damage due to irradiation. For short-range interaction the universal potential is used [J.F. Ziegler, J.P. Biersack, U. Littmark, The Stopping and Range of Ions in Solids, Pergamon Press, 1985, p. 41], while for long-range interaction, three different embedded atom method potentials [M.W. Finnis, J.E. Sinclair, Phil. Mag. A 50 (1984) 45; G.J. Ackland, R. Thetford, Phil. Mag. A 56 (1987) 15; P.M. Derlet, D. Nguyen-Manh, S.L. Dudarev, Phys. Rev. B 76 (2007) 054107] are used, namely, Finnis-Sinclair, Ackland-Thetford and Derlet-Nguyen-Manh-Dudarev, the latter providing a more accurate formation energy for the interstitial. The short-range and long-range potentials are smoothly connected. A new approach improving the reliability of such potential fits at short distances is presented. These potentials are then evaluated on the basis of displacement threshold, point defect formation and migration energies, thermal expansion and temperature of melting. Differences in the damage resulting from collision cascades are discussed.

  20. Radiation damage in diagnostic window materials for the TFTR

    International Nuclear Information System (INIS)

    The general problem of evaluating diagnostic window materials for the TFTR at the tank wall location is described. Specific evaluations are presented for several materials: vitreous silica, crystal quartz, sapphire, zinc selenide, and several fluorides: lithium fluoride, magnesium fluoride, and calcium fluoride; and seal glasses are discussed. The effects of the neutrons will be minimal. The major problems arise from the high flux of ionizing radiation, mainly the soft x rays which are absorbed near the surface of the materials. Additionally, this large energy deposition causes a significant thermal pulse with attendant thermal stresses. It is thus desirable to protect the windows with cover slips where this is feasible or to reduce the incident radiation by mounting the windows on long pipes. A more detailed summary is given at the end of this report

  1. Gamma radiation damage in crotamine (venom of Brazilian rattlesnake)

    International Nuclear Information System (INIS)

    Ionizing Radiations changes the molecular structure due to chemical bond destruction. These chemical alterations is able to change the biological properties of the macro-molecules. Crotamine was obtained from Crotalus durissus terrificus venom by molecular exclusion cromatography and irradiated in concentration of 2 mg/ml of NaCl 0,85% with gamma radiation produced by a 60Co source. We used doses of 100 Gy, 250 Gy, 500 Gy, 1000 Gy and 2000 Gy (dose rate = 1,19.103Gy/h). We performed the following experiments: presence of free SH groups, proteic concentration,SDS-PAGE and immunodifusion. Preliminary results showed an increase of the number of bands in SDS-PAGE suggesting the appearence of protein aggregates that proportional to the dose increasing. The immunodiffusion data showed no modification of the immunochemical activity against theButantan anti - sera. (author)

  2. UV radiation and freshwater zooplankton: damage, protection and recovery

    OpenAIRE

    Rautio, Milla; Tartarotti, Barbara

    2010-01-01

    While many laboratory and field studies show that zooplankton are negatively affected when exposed to high intensities of ultraviolet radiation (UVR), most studies also indicate that zooplankton are well adapted to cope with large variations in their UVR exposure in the pelagic zone of lakes. The response mechanisms of zooplankton are diverse and efficient and may explain the success and richness of freshwater zooplankton in optically variable waters. While no single behavioural or physiologi...

  3. Radiation damage in diopside and calcite crystals from uranothorianite inclusions

    OpenAIRE

    A.-M. Seydoux-Guillaume; J.-M. Montel; Richard Wirth; Moine, B.

    2009-01-01

    Combining observation and simulation, radiohalos formed around urano-thorianite (UTh) from the Tranomaro granulitic skarns (SE-Madagascar) were studied. These structures consist of UTh grains surrounded by both aluminous diopside (Cpx) and calcite (Cc1) crystals. Optical microscope and Scanning Electron Microscope (SEM) images revealed (1) the presence of radiating cracks around the UTh probably due to swelling of the metamict UTh, (2) a diffuse optical halo at the Cc1/UTh interface, and (3) ...

  4. An Assessment of Radiation Damage Models and Methods

    Energy Technology Data Exchange (ETDEWEB)

    Stoller, Roger E [ORNL; Mansur, Louis K [ORNL

    2005-05-01

    The current state of development of the primary models used for investigating and simulating irradiation effects in structural alloys of interest to the U.S. DOE's Generation-IV reactor program are discussed. The underlying theory that supports model development is also described where appropriate. First, the key processes that underlie radiation-induced changes in material properties are summarized, and the types of radiation effects that subsequently arise are described. Future development work needed in order for theory, modeling, and computational materials science to support and add value to the Gen IV reactor materials program are then outlined. The expected specific outcomes and overall benefits of the required effort are: the knowledge to extrapolate material behavior to conditions for which there are no experimental data; systematic understanding of mechanisms and processes to enable confident interpolation between point-by-point experimental observations; acceleration of the development, selection, and qualification of materials for reactor service; and prediction of material response to real-world operating load histories which often involve a complicated superposition of time, temperature, radiation dose rate, and mechanical loading conditions. Opportunities for international collaboration to accelerate progress in all of the required research areas are briefly discussed, particularly in the context of two well coordinated, broad-based research projects on modeling and simulation of radiation effects on materials that are currently funded in Europe. In addition to providing the opportunity for substantial leveraging of the DOE-funded activities in this area, these projects may serve as models for future development within the Gen-IV program. The larger of these two projects, which involves 12 European research laboratories and 16 universities, is called PERFECT and is funded by the European Union. A smaller effort focusing on developing predictive

  5. Neutron dosimetry for radiation damage in fission and fusion reactors

    International Nuclear Information System (INIS)

    The properties of materials subjected to the intense neutron radiation fields characteristic of fission power reactors or proposed fusion energy devices is a field of extensive current research. These investigations seek important information relevant to the safety and economics of nuclear energy. In high-level radiation environments, neutron metrology is accomplished predominantly with passive techniques which require detailed knowledge about many nuclear reactions. The quality of neutron dosimetry has increased noticeably during the past decade owing to the availability of new data and evaluations for both integral and differential cross sections, better quantitative understanding of radioactive decay processes, improvements in radiation detection technology, and the development of reliable spectrum unfolding procedures. However, there are problems caused by the persistence of serious integral-differential discrepancies for several important reactions. There is a need to further develop the data base for exothermic and low-threshold reactions needed in thermal and fast-fission dosimetry, and for high-threshold reactions needed in fusion-energy dosimetry. The unsatisfied data requirements for fission reactor dosimetry appear to be relatively modest and well defined, while the needs for fusion are extensive and less well defined because of the immature state of fusion technology. These various data requirements are examined with the goal of providing suggestions for continued dosimetry-related nuclear data research

  6. Radiation damage effects on X-ray silicon detectors

    International Nuclear Information System (INIS)

    The paper describes some results concerning technology and behaviour of X-and gamma-ray n+pp+ silicon detectors used in physics research, industrial and medical radiography and non-destructive testing. These detectors work at the room-temperature and can be used individually to detect X-and soft gamma-rays, or coupled with scintillators for higher incoming energies. Electrical characteristics of these photodiodes, their modification after exposure to radiation and results of spectroscopic X-and gamma-ray measurements are discussed. Devices manufactured under this technology proved to be stable after an exposure in high intensity gamma field with the dose range of 10 Krad-5 Mrad. Nuclear radiation resistance was studied by irradiation with 60 Co gamma source (1.17 and 1.33 MeV) at dose rates of 59 Krad/hour and 570 Krad/hour. Results indicate that proposed structures enable the development of reliable silicon detectors to be used in a high gamma-radiation environments encountered in a lot of applications. (authors)

  7. Cryopreservation and distribution of radiation-attenuated helminth larvae and the use of radioisotopes to monitor their survival. Coordinated programme on preparation of irradiated vaccines against some human diseases

    International Nuclear Information System (INIS)

    Techniques for the cryopreservation of schistosomula are described, from the methanol/two-step cooling technique, through a technique which uses 40% methanol and rapid cooling to the current technique which employs a two-step addition of ethanediol and rapid cooling. Levels of survival with these techniques have improved from 0.3% to 5.9% and now to 47% of control values. The 40% methanol/rapid cooling technique is described in detail as this forms the basis for understanding the role of cryoprotective additives and cooling and warming rates in the cryopreservation of schistosomula. The toxicity of 12 different potentially cryoprotective compounds is described. Cryopreservation of S.japonicum and S.bovis is described. The effect of the age of the schistosomula and their cryopreservability is related to the development of water sensitivity and the permeation and damage produced by glycerol and it is postulated that morphological changes occurring in the tegument during transformation from a cercaria to schistosomulum may account for these observations. Studies with 14C-ethanediol are described which attempt to provide an understanding of permeability of cryoprtectants to schistosomula of different ages and at different temperatures. Vaccination studies with cryopreserved and radiation-attenuated schistosomula are also reported. Radiation-attenuated schistosomula are also reported. Radiation-attenuated cercariae and schistosomula produced high (64% to 89%) levels of protection in baboons, and cryopreserved schistosomula produced comparable levels of protection in vaccinated mice to normal schistosomula. Cryopreserved radiation-attenuated schistosomula produced a significant level of protection (49% reduction) in sheep although the numbers of normally motile organisms injected was low (1,000 per dose, 2 doses). It is concluded that normally-motile cryopreserved radiation-attenuated schistosomula are as immunogenic as fresh organisms

  8. The Impact of 1,3-β-D-glucan Supplemented with Zinc Bis glycinate on gamma-radiation Induced Damage in Rats Lymphoid Tissues

    International Nuclear Information System (INIS)

    The Objective of this study was to evaluate the role of yeast glucan supplemented with Zn bis glycinate on radiation-induced oxidative damage in lymphoid tissues. Animals were orally supplemented with the composite in water suspension (65 mg I ,3-β-D-glucan Saccharomyces cerevisiae 100 mg Zn bis glycinate / kg body wt), 5 days before irradiation and within exposure to 8 Gy (2 Gyx 4 every other day). Rats were sacrificed 1,7, and 14 days post the last radiation dose. The results obtained showed that administration of the composite has significantly attenuated the radiation-induced increases of superoxide dismutase (SOD) activity and thiobarbituric acid reactive substances (TBARS) content and the decreases of catalase (CAT) and glutathione peroxidase (GSH-Px) activities and nitric oxide (NO) content, in the bone marrow and spleen. The significant improvement in the antioxidant status of lymphoid tissues was concomitant with significant amelioration in differential white blood cells (WBCs) count and serum C-reactive protein (CRP) and catecholamines (epinephrine; EPI and norepinephrine; NE) levels compared to their corresponding values in irradiated animals. It could be concluded that yeast glucan supplemented with Zn bis glycinate might modulate radiation immune responses by attenuating oxidative injury to lymphoid tissues, suggesting that it may have a potential benefit enhancing the success of radiotherapy and in situations where the effects of ionizing radiation are to be minimized

  9. Monte-Carlo studies of radiation damage in the first wall caused by fusion neutron

    International Nuclear Information System (INIS)

    The Monte-Carlo Neutron Transport Program and Neutron Radiation Damage Program are presented for studying radiation damage in the First Wall. The programs are used to static multi-component amorphous target. With the average wall load 1 MW/m2, the following calculating results for EHR first wall (type 316 stainless steel) have been performed by using designed neutron spectrums at EHR first wall: the PKA energy spectrums (30 eV to 1 MeV), average displacement per atom rate (20.6 dpa/a) and average helium and hydrogen production rates (247.18 appm/a and 721.15 appm/a). It shows that Hybrid Reactor's radiation damage is more serious than pure Fusion reactor's by comparison of above results and EHP's calculated results in the same wall load. the cross-section data from MC (87) n library is used in the calculation

  10. Nonlinear Ultrasonic Techniques to Monitor Radiation Damage in RPV and Internal Components

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, Laurence [Georgia Inst. of Technology, Atlanta, GA (United States); Kim, Jin-Yeon [Georgia Inst. of Technology, Atlanta, GA (United States); Qu, Jisnmin [Northwestern Univ., Evanston, IL (United States); Ramuhalli, Pradeep [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wall, Joe [Electric Power Research Inst. (EPRI), Knoxville, TN (United States)

    2015-11-02

    The objective of this research is to demonstrate that nonlinear ultrasonics (NLU) can be used to directly and quantitatively measure the remaining life in radiation damaged reactor pressure vessel (RPV) and internal components. Specific damage types to be monitored are irradiation embrittlement and irradiation assisted stress corrosion cracking (IASCC). Our vision is to develop a technique that allows operators to assess damage by making a limited number of NLU measurements in strategically selected critical reactor components during regularly scheduled outages. This measured data can then be used to determine the current condition of these key components, from which remaining useful life can be predicted. Methods to unambiguously characterize radiation related damage in reactor internals and RPVs remain elusive. NLU technology has demonstrated great potential to be used as a material sensor – a sensor that can continuously monitor a material’s damage state. The physical effect being monitored by NLU is the generation of higher harmonic frequencies in an initially monochromatic ultrasonic wave. The degree of nonlinearity is quantified with the acoustic nonlinearity parameter, β, which is an absolute, measurable material constant. Recent research has demonstrated that nonlinear ultrasound can be used to characterize material state and changes in microscale characteristics such as internal stress states, precipitate formation and dislocation densities. Radiation damage reduces the fracture toughness of RPV steels and internals, and can leave them susceptible to IASCC, which may in turn limit the lifetimes of some operating reactors. The ability to characterize radiation damage in the RPV and internals will enable nuclear operators to set operation time thresholds for vessels and prescribe and schedule replacement activities for core internals. Such a capability will allow a more clear definition of reactor safety margins. The research consists of three tasks: (1

  11. Accumulation of radiation damage in spinel crystals: Quantitative analysis and interpretation of RBS/C data

    International Nuclear Information System (INIS)

    Accumulation of radiation damage in magnesium aluminate spinel was studied using the Rutherford Backscattering/Channelling (RBS/C) technique. The possibilities offered by Monte-Carlo simulations of RBS/C spectra for the analysis of the disorder induced in spinel crystals by low and high energy ions are presented. A new model of damage accumulation based on the concept of multi-step destabilization of the crystal structure was developed and allowed us to correctly reproduce the experimental data

  12. Both Complexity and Location of DNA Damage Contribute to Cellular Senescence Induced by Ionizing Radiation

    OpenAIRE

    Xurui Zhang; Caiyong Ye; Fang Sun; Wenjun Wei; Burong Hu; Jufang Wang

    2016-01-01

    Persistent DNA damage is considered as a main cause of cellular senescence induced by ionizing radiation. However, the molecular bases of the DNA damage and their contribution to cellular senescence are not completely clear. In this study, we found that both heavy ions and X-rays induced senescence in human uveal melanoma 92-1 cells. By measuring senescence associated-β-galactosidase and cell proliferation, we identified that heavy ions were more effective at inducing senescence than X-rays. ...

  13. Deinococcus radiodurans PprI Switches on DNA Damage Response and Cellular Survival Networks after Radiation Damage*S⃞

    OpenAIRE

    Lu, Huiming; Gao, Guanjun; Xu, Guangzhi; Fan, Lu; Yin, Longfei; Shen, Binghui; Hua, Yuejin

    2009-01-01

    Preliminary findings indicate that PprI is a regulatory protein that stimulates transcription and translation of recA and other DNA repair genes in response to DNA damage in the extremely radioresistant bacterium Deinococcus radiodurans. To define the repertoire of proteins regulated by PprI and investigate the in vivo regulatory mechanism of PprI in response to γ radiation, we performed comparative proteomics analyses on wild type (R1) and a pprI knock-out strain (YR1) under conditions of io...

  14. Fluorescence studies on radiation oxidative damage to membranes with implications to cellular radiosensitivity

    Indian Academy of Sciences (India)

    K P Mishra

    2002-12-01

    Radiation oxidative damage to plasma membrane and its consequences to cellular radiosensitivity have received increasing attention in the past few years. This review gives a brief account of radiation oxidative damage in model and cellular membranes with particular emphasis on results from our laboratory. Fluorescence and ESR spin probes have been employed to investigate the structural and functional alterations in membranes after g-irradiation. Changes in the lipid bilayer in irradiated unilamellar liposomes prepared from egg yolk lecithin (EYL) were measured by using diphenylhexatriene (DPH) as a probe. The observed increase in DPH polarization and decrease in fluorescence intensity after g-irradiation of liposomes imply radiationinduced decrease in bilayer fluidity. Inclusion of cholesterol in liposome was found to protect lipids against radiation damage, possibly by modulation of bilayer organization e.g. lipid packing. Measurements on dipalmitoyl phosphatidylcholine (DPPC) liposomes loaded with 6-carboxyfluorescein (CF) showed radiation dose-dependent release of the probe indicating radiation-induced increased permeability. Changes in plasma membrane permeability of thymocytes were monitored by fluorescein diacetate (FDA) and induced intracellular reactive oxygen species (ROS) were determined by 2,7-dichlorodihydro fluorescein diacetate (DCH-FDA). Results suggest a correlation between ROS generation and membrane permeability changes induced by radiation within therapeutic doses (0-10 Gy). It is concluded that increase in membrane permeability was the result of ROS-mediated oxidative reactions, which might trigger processes leading to apoptotic cell death after radiation exposure.

  15. Attenuating microwave radiation by absorption through controlled nanoparticle localization in PC/PVDF blends.

    Science.gov (United States)

    Biswas, Sourav; Kar, Goutam Prasanna; Bose, Suryasarathi

    2015-11-01

    Nanoscale ordering in a polymer blend structure is indispensable to obtain materials with tailored properties. It was established here that controlling the arrangement of nanoparticles, with different characteristics, in co-continuous PC/PVDF (polycarbonate/poly(vinylidene fluoride)) blends can result in outstanding microwave absorption (ca. 90%). An excellent reflection loss (RL) of ca. -71 dB was obtained for a model blend structure wherein the conducting (multiwall carbon nanotubes, MWNTs) and the magnetic inclusions (Fe3O4) are localized in PVDF and the dielectric inclusion (barium titanate, BT) is in PC. The MWNTs were modified using polyaniline, which facilitates better charge transport in the blends. Furthermore, by introducing surface active groups on BT nanoparticles and changing the macroscopic processing conditions, the localization of BT nanoparticles can be tailored, otherwise BT nanoparticles would localize in the preferred phase (PVDF). In this study, we have shown that by ordered arrangement of nanoparticles, the incoming EM radiation can be attenuated. For instance, when PANI-MWNTs were localized in PVDF, the shielding was mainly through reflection. Now by localizing the conducting inclusion and the magnetic lossy materials in PVDF and the dielectric materials in PC, an outstanding shielding effectiveness of ca. -37 dB was achieved where shielding was mainly through absorption (ca. 90%). Thus, this study clearly demonstrates that lightweight microwave absorbers can be designed using polymer blends as a tool. PMID:26431367

  16. Schistosoma mansoni polypeptides immunogenic in mice vaccinated with radiation-attenuated cercariae

    International Nuclear Information System (INIS)

    We compared the humoral immune response of mice protected against Schistosoma mansoni by vaccination with radiation-attenuated cercariae to that of patently infected mice, and we identified antigens that elicit a greater, or unique, immune response in the vaccinated mice. These comparisons were based upon radioimmunoprecipitations and immunodepletion of [35S]methionine-labeled schistosomular and adult worm polypeptides, followed by one- and two-dimensional polyacrylamide gel analyses. The humoral responses of patently infected mice and of mice vaccinated once were remarkably similar and were directed against schistosome glycoproteins ranging in molecular size from greater than 300 to less than 10 kDa. Exposing mice to a second vaccination resulted in a marked change in the immune response, to one predominantly directed toward high molecular size glycoproteins. Sequential immunodepletion techniques identified five schistosomular and seven adult worm antigens that showed a greater or unique immunogenicity in vaccinated mice as compared with patently infected mice. These adult worm antigens were purified by preparative sequential immunoaffinity chromatography and used to prepare a polyclonal antiserum, anti-irradiated vaccine. This antiserum bound to the surface of live newly transformed and lung-stage schistosomula, as assessed by immunofluorescence assays, and was reactive with a number of 125I-labeled schistosomular surface polypeptides, including a doublet of 150 kDa that was also recognized by sera of vaccinated mice but not by sera of patently infected mice

  17. Schistosoma mansoni polypeptides immunogenic in mice vaccinated with radiation-attenuated cercariae

    Energy Technology Data Exchange (ETDEWEB)

    Dalton, J.P.; Strand, M.

    1987-10-01

    We compared the humoral immune response of mice protected against Schistosoma mansoni by vaccination with radiation-attenuated cercariae to that of patently infected mice, and we identified antigens that elicit a greater, or unique, immune response in the vaccinated mice. These comparisons were based upon radioimmunoprecipitations and immunodepletion of (/sup 35/S)methionine-labeled schistosomular and adult worm polypeptides, followed by one- and two-dimensional polyacrylamide gel analyses. The humoral responses of patently infected mice and of mice vaccinated once were remarkably similar and were directed against schistosome glycoproteins ranging in molecular size from greater than 300 to less than 10 kDa. Exposing mice to a second vaccination resulted in a marked change in the immune response, to one predominantly directed toward high molecular size glycoproteins. Sequential immunodepletion techniques identified five schistosomular and seven adult worm antigens that showed a greater or unique immunogenicity in vaccinated mice as compared with patently infected mice. These adult worm antigens were purified by preparative sequential immunoaffinity chromatography and used to prepare a polyclonal antiserum, anti-irradiated vaccine. This antiserum bound to the surface of live newly transformed and lung-stage schistosomula, as assessed by immunofluorescence assays, and was reactive with a number of /sup 125/I-labeled schistosomular surface polypeptides, including a doublet of 150 kDa that was also recognized by sera of vaccinated mice but not by sera of patently infected mice.

  18. Immunity to schistosomiasis mansoni in guinea-pigs vaccinated with radiation-attenuated cercariae

    International Nuclear Information System (INIS)

    The anti-schistosomular humoral responses of guinea-pigs vaccinated with radiation-attenuated cercariae of Schistosoma mansoni have been investigated in vitro. The sera of vaccinated animals contain schistosomulicidal complement-fixing antibodies which peak in titre at week 5 after vaccination and predominantly consist of IgG2 and IgM antibodies. The ability of the serum to arm macrophages from normal animals to bind to schistosomula, also peaks in titre at week 5 and is associated with IgG2 antibodies. Basophils from normal animals can be sensitized in vitro by vaccine serum to degranulate in the presence of schistosomular antigens. This anaphylactic antibody activity is associated with IgG1 but not IgE antibodies, and peaks in titre at week 10. Three antigens (14 kD, 20 kD and 43 kD) are specifically and transiently detected by vaccine serum on Western blots of schistosomular proteins; these antigens are first discernible at week 4, but were virtually undetectable at week 12. (author)

  19. Critical analysis of soil hydraulic conductivity determination using monoenergetic gamma radiation attenuation

    International Nuclear Information System (INIS)

    Three soil samples of different textures: LVA (red yellow latosol), LVE (dark red latosol) and LRd (dystrophic dark red latosol) were utilized for unsaturated hydraulic conductivity K(θ) measurements. Soil bulk densities and water contents during internal water drainage were measured by monoenergetic gamma radiation attenuation, using homogeneous soil columns assembled in the laboratory. The measurements were made with a collimated gamma beam of 0.003 m in diameter using a Nal(Tl) (3'' x 3 '') detector and a 137Cs gamma source of 74 X 108 Bq and 661.6 KeV. Soil columns were scanned with the gamma beam from 0.01 to 0.20 m depth, in 0.01m steps, for several soil water redistribution times. The results show a great variability of the unsaturated hydraulic conductivity relation K(θ), even though homogeneous soils were used. The variability among methods is significantly smaller in relation to variability in space. The assumption of unit hydraulic gradient during redistribution of soil water utilized in the methods of Hillel, Libardi and Sisson leads to hydraulic conductivity values that increase in depth. The exponential character of the K(θ) relationship, is responsible for the difficulty of estimating soil hydraulic conductivity, which is a consequence of small variations in the porous arrangement, even in samples supposed to be homogeneous. (author)

  20. Assessment of DNA damage in radiation workers by using single cell gel electrophoresis

    International Nuclear Information System (INIS)

    Objective: To assess the DNA damage of radiation workers in different grade hospitals, and to explore the correlation between the types of work or work time and the levels of DNA damage. Methods: DNA single strand break were detected by using alkaline single cell gel electrophoresis (SCGE), and the comet was analyzed with CASP (Comet Assay Software Project). TDNA%, TL, TM and OTM were calculated. Results: The parameters of SCGE in the radiation group were higher than those of control group (F=3.93, P<0.01). The significant difference was found not only among the different types of work or different work time, but also among the different grade hospitals (F=1.83, 1.91, P<0.05). Conclusions: Various levels of DNA damage could be detected in the radiation workers of the two hospitals. DNA damage of radiation workers is less serious in the higher-grade hospital than the lower grade one. Different types of work or work time might affect the DNA damage level. (authors)

  1. Repair of ionizing radiation DNA base damage in ataxia-telangiectasia cells

    International Nuclear Information System (INIS)

    Micrococcus luteus endonuclease sensitive sites were measured by alkaline elution in normal human and ataxia-telangiectasia (AT) fibroblasts after ionizing radiation. Due to the sensitivity of this assay, repair of base damage after 3 to 6 kilorads has been measured after oxic or hypoxic radiation. With 5.5 kilorads of oxic radiation, more than 50% of the base damage was removed after 1.5 h of repair incubation in all cells, including exr+ and exr- AT cells, and approximately 75% was removed by 4 h. After 3 or 4.5 kilorads of hypoxic X-irradiation, repair was equivalent in normal and exr- AT cells. This study included three exr- AT strains which have been reported to be deficient in the removal of gamma-ray base damage at higher doses. Since these strains repaired ionizing radiation base damage normally at lower doses, which are more relevant to survival, it is concluded that the X-ray hypersensitivity of AT cells is probably not related to the repair of base damage

  2. In-situ Attenuation Corrections for Radiation Force Measurements of High Frequency Ultrasound With a Conical Target.

    Science.gov (United States)

    Fick, Steven E; Ruggles, Dorea

    2006-01-01

    Radiation force balance (RFB) measurements of time-averaged, spatially-integrated ultrasound power transmitted into a reflectionless water load are based on measurements of the power received by the RFB target. When conical targets are used to intercept the output of collimated, circularly symmetric ultrasound sources operating at frequencies above a few megahertz, the correction for in-situ attenuation is significant, and differs significantly from predictions for idealized circumstances. Empirical attenuation correction factors for a 45° (half-angle) absorptive conical RFB target have been determined for 24 frequencies covering the 5 MHz to 30 MHz range. They agree well with previously unpublished attenuation calibration factors determined in 1994 for a similar target. PMID:27274946

  3. Delayed repair of radiation induced clustered DNA damage: Friend or foe?

    International Nuclear Information System (INIS)

    A signature of ionizing radiation exposure is the induction of DNA clustered damaged sites, defined as two or more lesions within one to two helical turns of DNA by passage of a single radiation track. Clustered damage is made up of double strand breaks (DSB) with associated base lesions or abasic (AP) sites, and non-DSB clusters comprised of base lesions, AP sites and single strand breaks. This review will concentrate on the experimental findings of the processing of non-DSB clustered damaged sites. It has been shown that non-DSB clustered damaged sites compromise the base excision repair pathway leading to the lifetime extension of the lesions within the cluster, compared to isolated lesions, thus the likelihood that the lesions persist to replication and induce mutation is increased. In addition certain non-DSB clustered damaged sites are processed within the cell to form additional DSB. The use of E. coli to demonstrate that clustering of DNA lesions is the major cause of the detrimental consequences of ionizing radiation is also discussed. The delayed repair of non-DSB clustered damaged sites in humans can be seen as a 'friend', leading to cell killing in tumour cells or as a 'foe', resulting in the formation of mutations and genetic instability in normal tissue.

  4. Data compilation for radiation damage on ceramic insulators

    International Nuclear Information System (INIS)

    Data of radiation effects on ceramic insulators were compiled from the literatures and summarized from the viewpoint of fast neutron irradiation effects. The data were classified according to the properties of ceramics. The properties are dimensional stability, mechanical property, thermal property and electrical and dielectric properties. The data sheets for each table or graph in the literatures were made. The characteristic feature of the data base was briefly described. As to swelling, the data were complied according to the dose dependence and the temperature dependence for each ceramics and reviewed briefly. (author)

  5. Crane RF accelerator for high current radiation damage studies

    International Nuclear Information System (INIS)

    An electron accelerator was designed and built for the Naval Weapons Support Center for transient radiation effects on electronics experiments and testing. The Crane L Band RF Electron Linac was designed to provide high currents over a wide range of pulse widths and energies. The energy extends to 60 MeV and pulse widths vary from a few ns to 10 μsec. Beam currents range from 20 amps in the short pulse case to 1.5 amps in the long pulse case. This paper describes the linac, its architecture, the e-gun and pulser, waveguides, klystrons and modulator, vacuum system, beam transport, and control systems. fig., tab

  6. Radiation damage measurements on CZT drift strip detectors

    DEFF Research Database (Denmark)

    Kuvvetli, Irfan; Budtz-Jørgensen, Carl; Korsbech, Uffe C C;

    2003-01-01

    At DSRI, in collaboration with the cyclotron facility at Copenhagen University Hospital, we have performed a study of radiation effects exposing a 2.7 mm thick CZT drift strip detector to 30 MeV protons. The detector characteristics were evaluated after exposure to a number of fluences in the range....... A numerical model that emulates the physical processes of the charge transport in the CZT detector was used to derive the charge trapping parameter, mutau(e), (the product of charge mobility and trapping time) as a function of fluence. The analysis showed that the electron trapping increased proportionately...

  7. Cranial nerve damage in patients after alpha (heavy)-particle radiation to the pituitary

    International Nuclear Information System (INIS)

    The records of 161 patients were reviewed to determine if radiation damage had occurred following cranial irradiation. All of these patients had received alpha-particle radiation to their pituitary glands during the period when this form of therapy was given for diabetic retinopathy. Extraocular muscle palsy developed in 11 of these patients, iridoplegia in six, and fifth nerve damage in six. All of the palsies developed within a short period following their irradiation, and a definite dose relationship was present. The dose rate was approximately 100 rads/min for all cases. Fractionation varied but it is known for all cases

  8. Cranial nerve damage in patients after alpha (heavy)-particle radiation to the pituitary

    International Nuclear Information System (INIS)

    The records of 161 patients were reviewed to determine if radiation damage had occurred following cranial irradiation. All of these patients had received alpha-particle radiation to their pituitary glands for diabetic retinopathy. Extraocular muscle palsy developed in 11 of these patients, iridoplegia in six, and fifth nerve damage in six. All of the palsies developed within a short period following their irradiation, and a definite dose relationship was present. The estimated doses to the third, fourth, fifth, and sixth cranial nerves was calculated at a saggital plane 13 to 15 mm from the pituitary by using computer-drawn dosimetry charts for the respective aperture size

  9. Radiation damage of heavy crystalline detector materials by 24 GeV protons

    Science.gov (United States)

    Barysevich, A.; Dormenev, V.; Fedorov, A.; Glaser, M.; Kobayashi, M.; Korjik, M.; Maas, F.; Mechinski, V.; Rusack, R.; Singovski, A.; Zoueyski, R.

    2013-02-01

    Samples of three heavy crystalline materials: PbWO4, Bi4Si3O12, and PbF2 were irradiated in a high-intensity 24 GeV proton beam at the CERN PS to fluencies of 3.8×1013 protons/cm2. The optical transmission radiation damage was measured and all crystals show a shift of the cutoff in the transmission spectrum that is not observed when the crystals are irradiated with γ radiation. This shift of the cutoff under proton irradiation seems to be a general property of the heavy crystalline materials. A mechanism for this proton-induced transmission damage is discussed.

  10. DAMSIG81. ECN Radiation Damage Cross Section Library. Contents and documentation

    International Nuclear Information System (INIS)

    DAMSIG81, the Radiation Damage Cross-Section Library by ECN, Netherlands, includes neutron cross-sections for about 20 reactor structural materials for calculating radiation damage by atomic displacements and by gas production, together with some additional related data. The data are presented in a 640 group structure similar to SAND-II. The library can be obtained free of charge from the IAEA Nuclear Data Section. The present version (DAMSIG81A) has a minor correction compared to the original version. (author)

  11. Effects of radiation damage caused by proton irradiation on Multi-Pixel Photon Counters (MPPCs)

    OpenAIRE

    Matsumura, T.; Matsubara, T.; Hiraiwa, T.; Horie, K.; Kuze, M.; Miyabayashi, K.; Okamura, A; Sawada, T.; Shimizu, S.; Shinkawa, T.; Tsunemi, T.; M. Yosoi

    2009-01-01

    We have investigated the effects caused by proton-induced radiation damage on Multi-Pixel Photon Counter (MPPC), a pixelized photon detector developed by Hamamatsu Photonics. The leakage current of irradiated MPPC samples linearly increases with total irradiated doses due to radiation damage, which is not completely recovered even after a year from the irradiation. No significant change has been observed in the gains at least up to 8.0 Gy ($9.1\\times10^7$ n/mm$^2$ in 1 MeV neutron equivalent ...

  12. DNA damage in human lymphocytes due to synergistic interaction between ionizing radiation and pesticide

    International Nuclear Information System (INIS)

    Biological risks may arise from the possibility of the synergistic interaction between harmful factors such as ionizing radiation and pesticide. The effect of pesticide on radiation-induced DNA damage in human in human blood lymphocytes was evaluated by the single cell gel electrophoresis (SCGE) assay. The lymphocytes, with or without pretreatment of the pesticide, were exposed to 2.0 Gy of gamma ray. Significantly increased tail moment, which was a marker of DNA strand breaks in SCGE assay, showed an excellent dose-response relationship. The present study confirms that the pesticide has the cytotoxic effect on lymphocytes and that it interacts synergistically with ionizing radiationon DNA damage, as well

  13. Des-Aspartate-Angiotensin I Attenuates Mortality of Mice Exposed to Gamma Radiation via a Novel Mechanism of Action.

    Directory of Open Access Journals (Sweden)

    Hong Wang

    Full Text Available ACE inhibitors and ARBs (angiotensin receptor blockers have been shown to attenuate radiation injuries in animal models of lethal gamma irradiation. These two classes of drug act by curtailing the actions of angiotensin II-linked inflammatory pathways that are up-regulated during gamma radiation in organ systems such as the brain, lung, kidney, and bone marrow. ACE inhibitors inhibit ACE and attenuate the formation of angiotensin II from angiotensin I; ARBs block the angiotensin AT1 receptor and attenuate the actions of angiotensin II that are elicited through the receptor. DAA-I (des-aspartate-angiotensin I, an orally active angiotensin peptide, also attenuates the deleterious actions of angiotensin II. It acts as an agonist on the angiotensin AT1 receptor and elicits responses that oppose those of angiotensn II. Thus, DAA-I was investigated for its anticipated radioprotection in gamma irradiated mice. DAA-I administered orally at 800 nmole/kg/day for 30 days post exposure (6.4 Gy attenuated the death of mice during the 30-day period. The attenuation was blocked by losartan (50 nmole/kg/day, i.p. that was administered sequential to DAA-I administration. This shows that the radioprotection was mediated via the angiotensin AT1 receptor. Furthermore, the radioprotection correlated to an increase in circulating PGE2 of surviving animals, and this suggests that PGE2 is involved in the radioprotection in DAA-I-treated mice. At the hematopoietic level, DAA-I significantly improved two syndromes of myelosuppression (leucopenia and lymphocytopenia, and mice pre-treated with DAA-I prior to gamma irradiation showed significant improvement in the four myelodysplastic syndromes that were investigated, namely leucopenia, lymphocytopenia, monocytopenia and thrombocytopenia. Based on the known ability of PGE2 to attenuate the loss of functional hematopoietic stem and progenitor cells in radiation injury, we hypothesize that PGE2 mediated the action of DAA

  14. Des-Aspartate-Angiotensin I Attenuates Mortality of Mice Exposed to Gamma Radiation via a Novel Mechanism of Action

    Science.gov (United States)

    Wang, Hong; Sethi, Gautam; Loke, Weng-Keong; Sim, Meng-Kwoon

    2015-01-01

    ACE inhibitors and ARBs (angiotensin receptor blockers) have been shown to attenuate radiation injuries in animal models of lethal gamma irradiation. These two classes of drug act by curtailing the actions of angiotensin II-linked inflammatory pathways that are up-regulated during gamma radiation in organ systems such as the brain, lung, kidney, and bone marrow. ACE inhibitors inhibit ACE and attenuate the formation of angiotensin II from angiotensin I; ARBs block the angiotensin AT1 receptor and attenuate the actions of angiotensin II that are elicited through the receptor. DAA-I (des-aspartate-angiotensin I), an orally active angiotensin peptide, also attenuates the deleterious actions of angiotensin II. It acts as an agonist on the angiotensin AT1 receptor and elicits responses that oppose those of angiotensn II. Thus, DAA-I was investigated for its anticipated radioprotection in gamma irradiated mice. DAA-I administered orally at 800 nmole/kg/day for 30 days post exposure (6.4 Gy) attenuated the death of mice during the 30-day period. The attenuation was blocked by losartan (50 nmole/kg/day, i.p.) that was administered sequential to DAA-I administration. This shows that the radioprotection was mediated via the angiotensin AT1 receptor. Furthermore, the radioprotection correlated to an increase in circulating PGE2 of surviving animals, and this suggests that PGE2 is involved in the radioprotection in DAA-I-treated mice. At the hematopoietic level, DAA-I significantly improved two syndromes of myelosuppression (leucopenia and lymphocytopenia), and mice pre-treated with DAA-I prior to gamma irradiation showed significant improvement in the four myelodysplastic syndromes that were investigated, namely leucopenia, lymphocytopenia, monocytopenia and thrombocytopenia. Based on the known ability of PGE2 to attenuate the loss of functional hematopoietic stem and progenitor cells in radiation injury, we hypothesize that PGE2 mediated the action of DAA-I. DAA-I completely

  15. Modification of radiation-induced oxidative damage in liposomal and microsomal membrane by eugenol

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, B.N. [Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Lathika, K.M. [Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Mishra, K.P. [Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)]. E-mail: kpm@magnum.barc.ernet.in

    2006-03-15

    Radiation-induced membrane oxidative damage, and their modification by eugenol, a natural antioxidant, was investigated in liposomes and microsomes. Liposomes prepared with DPH showed decrease in fluorescence after {gamma}-irradiation, which was prevented significantly by eugenol and correlated with magnitude of oxidation of phospholipids. Presence of eugenol resulted in substantial inhibition in MDA formation in irradiated liposomes/microsomes, which was less effective when added after irradiation. Similarly, the increase in phospholipase C activity observed after irradiation in microsomes was inhibited in samples pre-treated with eugenol. Results suggest association of radio- oxidative membrane damage with alterations in signaling molecules, and eugenol significantly prevented these membrane damaging events.

  16. Modification of radiation-induced oxidative damage in liposomal and microsomal membrane by eugenol

    Science.gov (United States)

    Pandey, B. N.; Lathika, K. M.; Mishra, K. P.

    2006-03-01

    Radiation-induced membrane oxidative damage, and their modification by eugenol, a natural antioxidant, was investigated in liposomes and microsomes. Liposomes prepared with DPH showed decrease in fluorescence after γ-irradiation, which was prevented significantly by eugenol and correlated with magnitude of oxidation of phospholipids. Presence of eugenol resulted in substantial inhibition in MDA formation in irradiated liposomes/microsomes, which was less effective when added after irradiation. Similarly, the increase in phospholipase C activity observed after irradiation in microsomes was inhibited in samples pre-treated with eugenol. Results suggest association of radio- oxidative membrane damage with alterations in signaling molecules, and eugenol significantly prevented these membrane damaging events.

  17. Effects of radiation damage on infra-red and thermoluminescence properties of natural apatites

    International Nuclear Information System (INIS)

    Thermoluminescence (TL) and infra-red (IR) spectra from various natural crystals of apatite have been examined. All naturally damaged samples (the amount of damage being monitored by their fossil fission track density) were found to exhibit a reduced contribution in the thermoluminescence glow intensity relative to that of undamaged one. Annealing the samples for 1 hour at temperatures above 500oC resulted in an increase in TL sensitivity. The investigation shows strong evidence that radiation damage is responsible for the reduced TL sensitivity. High uranium content in apatite sample shows an increasing IR peak intensity at 740 cm-1 with increasing annealing temperature. (Author)

  18. Radiation-induced chromosome damage in human lymphocytes

    International Nuclear Information System (INIS)

    Analysis for chromosome aberrations in human peripheral blood lymphocytes has been developed as an indicator of dose from ionising radiation. An outline is given of the mechanism of production of aberrations, the technique for their analysis and the dose-effect relationships for various types of radiation. During the past ten years the National Radiological Protection Board has developed a service for the UK in which estimates of dose from chromosomes aberration analysis are made on people known or suspected of being accidentally over-exposed. This service can provide estimates where no physical dosemeter was worn and is frequently able to resolve anomalous or disputed data from routine film badges. Several problems in the interpretation of chromosome aberration yields are reviewed. These include the effects of partial body irradiation and the response to variations in dose rate and the intermittent nature of some exposures. The dosimetry service is supported by a research programme which includes surveys of groups of patients irradiated for medical purposes. Two surveys are described. In the first, lymphocyte aberrations were examined in rheumatoid arthritis patients receiving intra-articular injections of colloidal radiogold or radioyttrium. A proportion of the nuclide leaked from the joint into the regional lymphatic system. In the second survey a comparison was made between the cytogenetic and physical estimates of whole body dose in patients receiving iodine 131 for thyroid carcinoma. (author)

  19. Evaluation of gamma radiation induced genetic damage in the fish Cyprinus carpio using comet assay

    International Nuclear Information System (INIS)

    Radionuclides released from various sources including the industries, as well as, accidental release during a nuclear disaster can contaminate inland water bodies. Suitable bio-monitoring methods/biomarkers are the need of the day to assess the impact of high/low levels of radiation exposure in aquatic environment. Fishes are very important as a group of ecologically and commercially important non-human biota and are often used as a bioindicators of aquatic pollution. Present work was carried out to assess the genotoxic effect of gamma radiation on fresh water fish Cyprinus carpio (common carp) in vivo using comet assay. Fishes were irradiated with 2, 4, 6, 8 and 10 Gy of gamma rays using a teletherapy machine and comet assay was performed on nucleated erythrocytes after 24, 48 and 72 h of irradiation . A significant increase in % tail DNA was observed at all the doses of gamma radiation as compared to controls indicating radiation induced DNA damage in a dose-dependent manner. Maximum % tail DNA was observed at 24 h which gradually declined till 72 h, in a time-dependent manner. This decrease in damage may indicate repair of the damaged DNA and or loss of heavily damaged cells, over a period of time. The study reveals that the comet assay may be used as a sensitive and rapid method to detect genotoxicity of gamma radiation and other environmental pollutants in sentinel species. (author)

  20. Radiation damage in InP single crystals and solar cells

    International Nuclear Information System (INIS)

    This paper shows that InP solar cell is more radiation resistant than Si and GaAs solar cells. 60Co γ-ray irradiation damage in InP solar cells was examined. Changes in minority carrier diffusion length and carrier concentration in irradiated InP single crystals were also investigated by electron beam induced current and capacitance-voltage methods for solar cells. A high carrier concentration p-InP substrate has lower concentration damage. Thus, an InP solar cell with a higher carrier concentration substrate has superior radiation resistance. Experimental results for radiation damage in InP solar cells were in satisfactory agreement with theoretical values, calculated from changes in minority carrier diffusion length and carrier concentration due to irradiation. Numerical analysis suggests that an InP solar cell with a higher carrier concentration substrate and a shallower junction should be relatively more radiation resistant. Annealing behavior for radiation damage in InP was also examined

  1. Evaluation of cytogenetic damage in nuclear medicine personnel occupationally exposed to low-level ionising radiation

    International Nuclear Information System (INIS)

    Despite intensive research over the last few decades, there still remains considerable uncertainty as to the genetic impact of ionising radiation on human populations, particularly at low levels. The aim of this study was to provide data on genetic hazards associated with occupational exposure to low doses of ionising radiation in nuclear medicine departments. The assessment of DNA damage in peripheral blood lymphocytes of medical staff was performed using the chromosome aberration (CA) test. Exposed subjects showed significantly higher frequencies of CA than controls. There were significant inter-individual differences in DNA damage within the exposed population, indicating differences in genome sensitivity. Age and gender were not confounding factors, while smoking enhanced the levels of DNA damage only in control subjects. The present study suggests that chronic exposure to low doses of ionising radiation in nuclear medicine departments causes genotoxic damage. Therefore, to avoid potential genotoxic effects, the exposed medical personnel should minimise radiation exposure wherever possible. Our results also point to the significance of biological indicators providing information about the actual risk to the radiation exposed individuals.(author)

  2. Use of lectin-induced lymphocyte stimulation as a biodosimeter of radiation damage

    International Nuclear Information System (INIS)

    The purpose of this study was to determine the feasibility of utilizing an in vitro test to determine whether an individual has suffered radiation damage. It was not our purpose to develop a test capable of detecting low doses but rather to determine possible damage due to a radiation accident at medium to high doses. In a pilot study using the whole blood lymphocyte stimulation test (WB/LST), we pretested six dogs weekly for three weeks. One was sham irradiated and is referred to as the control and one each received an acute whole body dose of 10, 25, 50, 75, or 100 R. The dogs were tested one day post-irradiation and then weekly for 56 days. Our data indicate that, using Con-A and PHA in the WB/LST, a biodosimeter can be developed to determine recovery of lymphocyte function after suspected radiation exposure to confirm accidental radiation and estimate the magnitude of the dose

  3. Dragon's blood and its extracts attenuate radiation-induced oxidative stress in mice

    International Nuclear Information System (INIS)

    Dragon's blood (DB) possesses great medicinal values due to the presence of several phenolic compounds. This study was designed to investigate the effects of DB and its extracts (DBEs) on oxidative stress in mice exposed to whole body 60Co-γ irradiation (4 Gy). DB and DBEs were intragastrically administered to mice for 5 d prior to radiation. The antioxidant activities, including malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) levels in liver and spleen were measured using kits. Furthermore, DB and DBE effects were determined by organ indices and histology of liver and spleen. Our results indicated that the DB and DBE-treated groups showed a significant decrease (P < 0.05) in levels of MDA in liver and spleen compared with the irradiation-only group. Moreover, the activity of SOD, CAT and the level of GSH in liver and spleen tissue were enhanced significantly (P < 0.05) in the DB and DBE groups. DB and DBE also had a significant effect on the recovery of thymus indices. The histological observations of groups having treatment with DB and DBE indicated significant reduction in the radiation-induced damage to the liver and spleen, together with improvement in the morphology of the liver and spleen. These results suggest that DB and DBE treatment prevents radiation-induced oxidative stress injury and restores antioxidant status and histopathological changes in the liver and spleen, but there is need for further study to explore the precise molecular mechanism and strategy for optimal practical application of DB and DBE. (author)

  4. Radiation and transposon-induced genetic damage in Drosophila melanogaster

    International Nuclear Information System (INIS)

    The interaction of X-ray-induced and transposon-induced damage was investigated in P-M hybrid dysgenesis in Drosophila melanogaster. X-ray dose-response of 330-1320 rad was monitored for sterility, fecundicity and partial X/Y chromosome loss among F2 progeny derived from dysgenic cross of M strain females xP strain males (cross A) and its reciprocal (cross B), using a weaker and the standard Harwich P strain subline. The synergistic effect of P element activity and X-rays on sterility was observed only in cross A hybrids and the dose-response was nonlinear in hybrids derived from the strong standard reference Harwich subline, HW. This finding suggests that lesions induced by both mutator systems which produce the synergistic effects are 2-break events. Effect of increasing dose on the decline of fecundicity was synergistic, but linear, in hybrids of either subline. There was no interaction evident and thus no synergism in X/Y nondisjunction and partial Y chromosome loss measured by the loss of the Bs marker alone or together with the y+ marker. Interaction was detected in the loss of the y+ marker alone from the X and Y chromosomes. The possible three-way interaction of X-rays (660 rad), post-replication repair deficiency and P elements mobility was assessed by measuring transmission distortion in dysgenic males derived from the Π2 P strain. (author). 38 refs.; 5 tabs

  5. Ion-counting nanodosimetry: a new method for assessing radiation damage to DNA

    Energy Technology Data Exchange (ETDEWEB)

    Shchemelinin, S.; Garty, G.; Breskin, A.; Chechik, R. E-mail: fnchecik@wisemail.weizmann.ac.il; Schulte, R.W.M

    2002-01-21

    A novel nanodosimeter is described, based on ion counting. It provides precise model-evaluation of radiation-induced ionization patterns in small condensed-matter volumes of nanometric size. The nanodosimeter consists of a millimetric, low-pressure, wall-less gas cell, serving as an expanded model of a nanometric condensed-matter volume. The method can also be employed for the assessment of radiation damage to advanced nanoelectronics.

  6. Ion-counting nanodosimetry: a new method for assessing radiation damage to DNA

    Science.gov (United States)

    Shchemelinin, S.; Garty, G.; Breskin, A.; Chechik, R.; Schulte, R. W. M.

    2002-01-01

    A novel nanodosimeter is described, based on ion counting. It provides precise model-evaluation of radiation-induced ionization patterns in small condensed-matter volumes of nanometric size. The nanodosimeter consists of a millimetric, low-pressure, wall-less gas cell, serving as an expanded model of a nanometric condensed-matter volume. The method can also be employed for the assessment of radiation damage to advanced nanoelectronics.

  7. Ion-counting nanodosimetry: a new method for assessing radiation damage to DNA

    International Nuclear Information System (INIS)

    A novel nanodosimeter is described, based on ion counting. It provides precise model-evaluation of radiation-induced ionization patterns in small condensed-matter volumes of nanometric size. The nanodosimeter consists of a millimetric, low-pressure, wall-less gas cell, serving as an expanded model of a nanometric condensed-matter volume. The method can also be employed for the assessment of radiation damage to advanced nanoelectronics

  8. Consequences of PAI-1 specific deletion in endothelium on radiation-induced intestinal damage

    International Nuclear Information System (INIS)

    Radiation-induced injury to healthy tissues is a real public health problem, since they are one of the most limiting factors that restrict efficiency of radiation therapy. This problematic is also part of the French Cancer Plan 2014-2017, and involves clinical research. Concepts surrounding the development of radiation-induced damage have gradually evolved into a contemporary and integrated view of the pathogenesis, involving all compartments of target tissue. Among them, endothelium seems to be central in the sequence of interrelated events that lead to the development of radiation-induced damage, although there are rare concrete elements that support this concept. By using new transgenic mouse models, this PhD project provides a direct demonstration of an endothelium-dependent continuum in evolution of radiation-induced intestinal damage. Indeed, changes in the endothelial phenotype through targeted deletion of the gene SERPINE1, chosen because of its key role in the development of radiation enteritis, influences various parameters of the development of the disease. Thus, lack of PAI-1 secretion by endothelial cells significantly improves survival of the animals, and limits severity of early and late tissue damage after a localized small bowel irradiation. Furthermore, these mice partially KO for PAI-1 showed a decrease in the number of apoptotic intestinal stem cells in the hours following irradiation, a decrease in the macrophages infiltrate density one week after irradiation, and a change in the polarization of macrophages throughout the pathophysiological process. In an effort to protect healthy tissues from radiation therapy side effects, without hindering the cancer treatment, PAI-1 seems to be an obvious therapeutic target. Conceptually, this work represents the direct demonstration of the link between endothelium phenotype and radiation enteritis pathogenesis. (author)

  9. Concurrent Transient Activation of Wnt/{beta}-Catenin Pathway Prevents Radiation Damage to Salivary Glands

    Energy Technology Data Exchange (ETDEWEB)

    Hai Bo; Yang Zhenhua; Shangguan Lei; Zhao Yanqiu [Institute for Regenerative Medicine, Scott and White Hospital, Molecular and Cellular Medicine Department, Texas A and M Health Science Center, Temple, Texas (United States); Boyer, Arthur [Department of Radiology, Scott and White Hospital, Temple, Texas (United States); Liu, Fei, E-mail: fliu@medicine.tamhsc.edu [Institute for Regenerative Medicine, Scott and White Hospital, Molecular and Cellular Medicine Department, Texas A and M Health Science Center, Temple, Texas (United States)

    2012-05-01

    Purpose: Many head and neck cancer survivors treated with radiotherapy suffer from permanent impairment of their salivary gland function, for which few effective prevention or treatment options are available. This study explored the potential of transient activation of Wnt/{beta}-catenin signaling in preventing radiation damage to salivary glands in a preclinical model. Methods and Materials: Wnt reporter transgenic mice were exposed to 15 Gy single-dose radiation in the head and neck area to evaluate the effects of radiation on Wnt activity in salivary glands. Transient Wnt1 overexpression in basal epithelia was induced in inducible Wnt1 transgenic mice before together with, after, or without local radiation, and then saliva flow rate, histology, apoptosis, proliferation, stem cell activity, and mRNA expression were evaluated. Results: Radiation damage did not significantly affect activity of Wnt/{beta}-catenin pathway as physical damage did. Transient expression of Wnt1 in basal epithelia significantly activated the Wnt/{beta}-catenin pathway in submandibular glands of male mice but not in those of females. Concurrent transient activation of the Wnt pathway prevented chronic salivary gland dysfunction following radiation by suppressing apoptosis and preserving functional salivary stem/progenitor cells. In contrast, Wnt activation 3 days before or after irradiation did not show significant beneficial effects, mainly due to failure to inhibit acute apoptosis after radiation. Excessive Wnt activation before radiation failed to inhibit apoptosis, likely due to extensive induction of mitosis and up-regulation of proapoptosis gene PUMA while that after radiation might miss the critical treatment window. Conclusion: These results suggest that concurrent transient activation of the Wnt/{beta}-catenin pathway could prevent radiation-induced salivary gland dysfunction.

  10. Radiation damage in negative-differential resistance devices

    International Nuclear Information System (INIS)

    Tunnel diodes made with silicon and gallium arsenide have been tested in both neutron- and gamma-radiation environments. Experimental data show that failure usually occurs in the range 1014-1018 n cm-2 or 50-270 Mrad range. The primary failure mechanism for neutron irradiated samples is an increase in the valley current (from 0.10 mA to 0.58 mA and from 1.5 μA to 30 μA for silicon and GaAs diodes, respectively). In the case of gamma-irradiated silicon samples, the valley current reaches a value of 0.48 mA, at 260.8 Mrad, although their initial values are 0.1 mA. As a result, the peak-to-valley current ratios of the irradiated devices were shown to decrease severely. Both the valley and forward peak voltage values were shown to decrease with radiation. Values of 0.18 and 0.25 V for silicon samples were measured after exposure to 5 x 1016 n cm-2 although their initial values were 0.42 and 0.80 V, respectively. As a result, the devices' output power were shown to be affected seriously. Finally, silicon devices irradiated for 48 h in the ET-RR-1 research reactor, Egypt, for up to 1.872 x 1018 n cm-2 or to gamma doses up to 2.6 x 108 rad, were greatly influenced and they lost their main feature as PN-junctions. (Author)

  11. Protection against radiation-induced damage - Experimental radioprotection

    International Nuclear Information System (INIS)

    Chemical radiation protection in rodents was first discovered in 1949 and clinical application in cases of acute radiation sickness seemed to be promising. Numerous chemicals were screened in various laboratories, but clinically available chemical protectors were not discovered. It was concluded in 1962 that although a number of compounds may be capable of efficient protection of mice when given before exposure to X or γ rays, none could be considered a practical agent for protection of humans. On the basis of synthesis, stability, and effectiveness of oral administration, as well as dose-reduction properties, S-(2-aminoethyl)isothiouronium (AET) would seem to be the drug of choice. However, preliminary tests of AET in humans indicated that the toxicity may be far too great. New chemical protectors have been reported, following two different lines of research in Japan and in the United States. In Japan, an adrenochrome derivative, adrenochrome monoguanylhydrazone methanesulfonate (AMM) and a new sulfhydrl compound, 2-mercaptopropionylglycine (MPG), which are both effective in much lower doses than their toxic dose in mice, were reported. In the United States, after a large screening of various kinds of derivatives of cysteamine, WR-2721, S-2-(3-aminopropylamino)ethylphosphorothioic acid was reported to have a very high dose-reduction factor of 2.5 or more, thus effective even at a less toxic dose. To make use of these chemicals in cases of cancer radiotherapy, differential protection between tumor and normal tissues has to be established. Studies along this line have been also carried out with WR-2721 and MPG. The results obtained so far are promising for the improvement of radiotherapy. In this chapter, experimental studies on these chemicals are reviewed, emphasizing the authors own research

  12. Cytokine production in BALB/c mice immunized with radiation attenuated third stage larvae of the filarial nematode, Brugia pahangi

    International Nuclear Information System (INIS)

    BALB/c mice immunized with radiation-attenuated third stage larvae of the filarial nematode Brugia pahangi are strongly immune to challenge infection. Investigation of the profile of cytokines secreted by spleen cells from immune mice stimulated in vitro with either parasite Ag or with Con A revealed high levels of IL-5 and IL-9 and moderate levels of IL-4. In contrast, secretion of IFN-γ by spleen cells from immune animals was negligible. Spleen cells from control mice secreted low levels of all cytokines assayed. Levels of parasite-specific IgE were significantly elevated in immune animals and a peripheral blood eosinophilia was observed, which exhibited a biphasic distribution. Our results are consistent with the preferential expansion of Th2 cells in immune animals and provide the basis for dissecting the means by which radiation-attenuated larvae of filarial nematodes stimulate immunity. 5l refs., 3 figs., 3 tabs

  13. Curcumin protects oxidative stress and DNA damage induced by metronidazole and gamma radiation in vivo

    International Nuclear Information System (INIS)

    Metronidazole (MTZ), 1-(2-hydroxyethyl)-2-methyl-5-nitroimidazole, an antiparasitic and antibacterial compound, is one of the world's most used drugs. The DNA damaging effect of ionizing radiation (RAD) is well established. Curcumin has been reported to scavenge oxygen free radicals and protect the cellular macromolecules including DNA from oxidative damage. In the present study we investigated the DNA damaging and oxidative stress caused by low dose radiation in MTZ treated mice and evaluated curcumin's protective effects. Curcumin pretreated Swiss albino mice were treated with 13.4 mg/kg bw MTZ intraperitoneally for three days and irradiated with 0.5 Gy ionizing radiation. They were sacrificed after 24 hrs of last exposure. In vivo comet assay and biochemical estimations were conducted as per standard protocol. MTZ alone and in combination with gamma radiation lead to statistically significant increase in the percentage contents of DNA in the comet tail. Hepatic superoxide dismutase and reduced glutathione declined significantly with significant rise in TBARS of the tissue. Combined treatment of MTZ and RAD showed additive effects that are greater than individual effects which were statistically significant. Our result indicates the genotoxicity of the combined effect of low dose radiation and MTZ on exposed group. Curcumin exhibits strong protective role against the MTZ and radiation induced genotoxicity. This finding opens a new access to drug mutagen interaction and vital role of curcumin as an antioxidant. (author)

  14. Assessment of radiation-induced damage to DNA at the molecular level by mass spectrometry

    International Nuclear Information System (INIS)

    Full text: Ionizing radiation-induced damage to DNA in living cells may lead to biological consequences such as mutation, carcinogenesis or cell death. Free radicals generated from water by ionising radiation, especially OH radicals produce a large number of base and sugar derived stable products in DNA as well as DNA-protein complexes. Repair of these structural modifications is essential to maintain the genomic integrity to prevent long term effects of radiation. Understanding the cellular repair of ionizing radiation-induced damage to DNA in cell obviously depends upon the knowledge of the chemical nature of DNA lesions and their quantities at the molecular level. Several types of assays are known to measure the yields of radiation-induced purine and pyrimidine products in DNA which include chromatographic, immunochemical or biochemical technologies. However, these procedures are capable of assaying only a very limited number of modified DNA products and lack sensitivity and selectivity. We have developed sensitive and specific gas chromatography-mass spectrometry methods (GC/MS) for chemical identification and estimation of modifications in DNA at physiologically relevant doses. This presentation will focus primarily on the sampling, instrumentation, applications and limitations of GC/MS procedures in assaying radiation-induced damage and repair to DNA

  15. Radiation induced apoptosis and initial DNA damage are inversely related in locally advanced breast cancer patients

    Directory of Open Access Journals (Sweden)

    Rodriguez-Gallego Carlos

    2010-09-01

    Full Text Available Abstract Background DNA-damage assays, quantifying the initial number of DNA double-strand breaks induced by radiation, have been proposed as a predictive test for radiation-induced toxicity. Determination of radiation-induced apoptosis in peripheral blood lymphocytes by flow cytometry analysis has also been proposed as an approach for predicting normal tissue responses following radiotherapy. The aim of the present study was to explore the association between initial DNA damage, estimated by the number of double-strand breaks induced by a given radiation dose, and the radio-induced apoptosis rates observed. Methods Peripheral blood lymphocytes were taken from 26 consecutive patients with locally advanced breast carcinoma. Radiosensitivity of lymphocytes was quantified as the initial number of DNA double-strand breaks induced per Gy and per DNA unit (200 Mbp. Radio-induced apoptosis at 1, 2 and 8 Gy was measured by flow cytometry using annexin V/propidium iodide. Results Radiation-induced apoptosis increased in order to radiation dose and data fitted to a semi logarithmic mathematical model. A positive correlation was found among radio-induced apoptosis values at different radiation doses: 1, 2 and 8 Gy (p Conclusions An inverse association was observed for the first time between these variables, both considered as predictive factors to radiation toxicity.

  16. Radiation damage measurements of FET's using a radiation monitor, RadMon for LIU

    International Nuclear Information System (INIS)

    RadMon is the radiation monitor which is developed at CERN to measure the radiation dose, neutron flux and high energy particle at the same time. We are collaborating with CERN for the consolidation and upgrade of the CERN PSB RF system which may include the replacement of the present ferrite-base RF accelerating system by the new FT3L magnetic alloy cavity system. The FT3L cavities will be driven by the solid state amplifiers beside of them. To evaluate the radiation damage on the solid state amplifiers in the PSB tunnel, we measured radiation damage on the FET using the J-PARC MR beam. We located the FET's and the radiation monitor, RadMon, downstream of the collimator where the radiation level is the highest in the ring. We measured the variation of bias characteristics of the FET's during the machine operation. The accumulated dose during the experiment became higher than 12 kGy which is much higher than the expected dose in the CERN PSB tunnel. Based on the measurements, we decide the FET for the solid state amplifiers. The beam acceleration test using the amplifiers will be performed in this year. (author)

  17. Study of radiation damages in AISI 316 and 347 steels

    International Nuclear Information System (INIS)

    The CV-28 cyclotron at IEN (Nuclear Engineering Institute) has been used to simulated, in a short time scale, uniform He concentrations produced during neutron irradiation of metals by (n, α) reactions. Helium was implanted at concentrations of 1 to 300 ppm in 100 μm thick sheet samples of AISI 316 and 347 S S by degrading a 28 MeV alpha particle beam with a rotating energy degrader. The effects of He on the mechanical properties of the steels were studied by both non-destructive (positron annihilation) and destructive tests (tensile, creep, TEM and SEM). The positron lifetime measurements of irradiated and annealed samples were used as the base to discuss the He diffusion mechanism. Activation energies of 0.34±0.04 eV for 316 S S and 0.57±0.06 eV for 347 S S, characterized a dissociative process above 6500 C. TEM analyses have suggested the Ostwald ripening process for bubble growth over the full range of He concentrations studied. It was shown, in agreement with theoretical calculations that, by themselves the displacements produced during the helium implantation, at rate of 1.8 x 10-3 d pa/ppm, were not sufficient to cause significant changes in ductility. However, a strong ductility loss with increasing He concentration was observed for both types of steel for tensile tests at 250 C, as well as in creep at 7500 C over the range of strain (100 to 200 MPa). Finally, it was shown that charged particle simulation associated with positron annihilation techniques provides a fast, relatively low cost, and useful method to study different kinds of neutron damage in materials. (author)

  18. N-acetyl Cysteine Reduced Oxidative Damages in Guinea Pigs Exposed to Cigarette Smoke and / or Gamma Radiation

    International Nuclear Information System (INIS)

    The objective of this study was to evaluate the role of n-acetyl cysteine (NAC) supplementation on oxidative cigarette smoke induced-oxidative damage in irradiated guinea pigs. N-acetyl cysteine was injected (i.p) to guinea pigs at a dose of 150 mg/kg b. w/day pre-exposure to cigarette smoke for one hour daily for 30 successive days. Animals were submitted to fractionate whole body gamma radiation (2 Gy installment every two weeks up to 4 Gy total dose started on the 2nd week of the experiment). Animals were sacrificed during the first hours from the last treatment of cigarette smoke. The results obtained showed significant increase in malondialdehyde (MDA) content associated with decreased superoxide dismutase (SOD) activity and glutathione (GSH) concentration in cardiac and pulmonary tissues as compared with their equivalent in control animals. The activities of lactate dehydrogenase (LDH), creatine phosphokinase (CPK), aspartate transaminase (AST), concentration of nitric oxide (NO), total cholesterol, Triacylglycerol, LDL-cholesterol were significant increased in plasma associated with significant decreased HDL-cholesterol. The administration of NAC has significantly attenuated the cigarette smoke and/or irradiation-induced changes in all the studied parameters. It could be concluded that NAC reduced cigarette smoke and radiation hazards via neutralized their capability to generate excessive reactive oxygen species (ROS) and free radicals in the biological systems

  19. Development of radiation attenuated antiparasitic vaccines and their impact on control of livestock diseases in India- a review

    International Nuclear Information System (INIS)

    The development of the first antiparasitic D. filaria vaccine in India, its impact upon the control of lung worm infections in enzootic areas besides the work done on immunological control of parasitic infections of animals, using radiation attenuated infective stages of the parasites as immunogens and future prospects of such crude antigens as vaccine and their application in control of parasitic diseases vis-a-vis increased animal productivity are traced in this review. 16 refs., 1 tab

  20. Macrophages as effector cells of protective immunity in murine schistosomiasis: macrophage activation in mice vaccinated with radiation-attenuated cercariae.

    OpenAIRE

    James, S L; Natovitz, P C; Farrar, W L; Leonard, E.J.

    1984-01-01

    Cell-mediated immune responses contributing to macrophage activation were compared in mice that demonstrated partial resistance to challenge Schistosoma mansoni infection as a result of vaccination with radiation-attenuated cercariae or of ongoing low-grade primary infection. Vaccinated mice developed significant delayed hypersensitivity reactions to soluble schistosome antigens in vivo. Splenocytes from vaccinated animals responded to in vitro culture with various specific antigens (soluble ...