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Sample records for radiation damage sunlight

  1. Quantification of ultraviolet radiation-induced DNA damage in the urine of Swedish adults and children following exposure to sunlight.

    Science.gov (United States)

    Liljendahl, Tove Sandberg; Kotova, Natalia; Segerbäck, Dan

    2012-11-01

    DNA damage following exposure to ultraviolet radiation (UVR) is important in skin cancer development. The predominant photoproduct, cyclobutane thymine dimer (T=T), is repaired and excreted in the urine, where it provides a biomarker of exposure. To quantify urinary T=T levels after recreational sunlight exposure in adults and children. Average UVR doses were measured with personal dosimeters. Urinary T=T was analysed with (32)P-postlabelling. Background levels of T=T increased significantly following exposure to sunlight. Amounts of T=T in urine of children and adults were not significantly different after adjusting for area of skin exposed and physiological differences. UVR dose and amounts of T=T correlated for both adults and children. Recreational exposure to sunlight in Sweden induces levels of DNA damage, clearly detectable in urine.

  2. Sunlight-induced DNA damage in human mononuclear cells

    DEFF Research Database (Denmark)

    Møller, Peter; Wallin, Hakan; Holst, Erik

    2002-01-01

    of sunlight was comparable to the interindividual variation, indicating that sunlight exposure and the individual's background were the two most important determinants for the basal level of DNA damage. Influence of other lifestyle factors such as exercise, intake of foods, infections, and age could......In this study of 301 blood samples from 21 subjects, we found markedly higher levels of DNA damage (nonpyrimidine dimer types) in the summer than in the winter detected by single-cell gel electrophoresis. The level of DNA damage was influenced by the average daily influx of sunlight ... to blood sampling. The 3 and 6 day periods before sampling influenced DNA damage the most. The importance of sunlight was further emphasized by a positive association of the DNA damage level to the amount of time the subjects had spent in the sun over a 3 day period prior to the sampling. The effect...

  3. Radiation damage

    CERN Document Server

    Heijne, Erik H M; CERN. Geneva

    1998-01-01

    a) Radiation damage in organic materials. This series of lectures will give an overview of radiation effects on materials and components frequently used in accelerator engineering and experiments. Basic degradation phenomena will be presented for organic materials with comprehensive damage threshold doses for commonly used rubbers, thermoplastics, thermosets and composite materials. Some indications will be given for glass, scintillators and optical fibres. b) Radiation effects in semiconductor materials and devices. The major part of the time will be devoted to treat radiation effects in semiconductor sensors and the associated electronics, in particular displacement damage, interface and single event phenomena. Evaluation methods and practical aspects will be shown. Strategies will be developed for the survival of the materials under the expected environmental conditions of the LHC machine and detectors. I will describe profound revolution in our understanding of black holes and their relation to quantum me...

  4. Sunlight exposure-mediated DNA damage in young adults.

    Science.gov (United States)

    Kato, Masashi; Iida, Machiko; Goto, Yuji; Kondo, Takaaki; Yajima, Ichiro

    2011-08-01

    Previous experimental studies showed that single ultraviolet B (UVB) light irradiation increased levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a well-established biomarker of carcinogenesis and oxidative DNA damage, in epithelial cells in animals and humans. We conducted for the first time an epidemiologic study to investigate the correlations among levels of oxidative DNA damage, skin pigmentation, and sunlight exposure in human daily life. Digitalized skin pigmentation levels and creatinine-adjusted urinary 8-OHdG levels were examined in 127 healthy young adults aged 20 to 24 years and in hairless mice with normal pigmented skin (HL-mice; n = 20) and hyperpigmented skin (HL-HPS-mice; n = 20). Data obtained by a questionnaire were also analyzed for the 127 subjects. Binary logistic regression analysis showed that increased sunlight intensity, but not sunlight-exposed time or sunlight-exposed skin area, was correlated with elevation in creatinine-adjusted urinary 8-OHdG levels. In contrast, increased skin pigmentation level, but not the use of sunscreen, was correlated with reduction in urinary 8-OHdG level in humans. UVB irradiation corresponding to several minutes of sunlight exposure significantly increased urinary 8-OHdG levels in HL-mice but not in HL-HPS-mice. We showed that increase in intensity of sunlight in human daily life increased levels of DNA damage. We also showed a protective effect of skin pigmentation on sunlight exposure-mediated DNA damage. We have provided more reliable evidence of routine sunlight exposure-mediated DNA damage in humans through the combination of epidemiologic and experimental studies. ©2011 AACR.

  5. Preventive role of lens antioxidant defense mechanism against riboflavin-mediated sunlight damaging of lens crystallins.

    Science.gov (United States)

    Anbaraki, Afrooz; Khoshaman, Kazem; Ghasemi, Younes; Yousefi, Reza

    2016-10-01

    The main components of sunlight reaching the eye lens are UVA and visible light exerting their photo-damaging effects indirectly by the aid of endogenous photosensitizer molecules such as riboflavin (RF). In this study, lens proteins solutions were incubated with RF and exposed to the sunlight. Then, gel mobility shift analysis and different spectroscopic assessments were applied to examine the structural damaging effects of solar radiation on these proteins. Exposure of lens proteins to direct sunlight, in the presence of RF, leads to marked structural crosslinking, oligomerization and proteolytic instability. These structural damages were also accompanied with reduction in the emission fluorescence of Trp and Tyr and appearance of a new absorption peak between 300 and 400nm which can be related to formation of new chromophores. Also, photo-oxidation of lens crystallins increases their oligomeric size distribution as examined by dynamic light scattering analysis. The above mentioned structural insults, as potential sources of sunlight-induced senile cataract and blindness, were significantly attenuated in the presence of ascorbic acid and glutathione which are two important components of lens antioxidant defense system. Therefore, the powerful antioxidant defense mechanism of eye lens is an important barrier against molecular photo-damaging effects of solar radiations during the life span. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. The genotoxic effects of DNA lesions induced by artificial UV-radiation and sunlight.

    Science.gov (United States)

    Schuch, André Passaglia; Menck, Carlos Frederico Martins

    2010-06-01

    Solar radiation sustains and affects all life forms on Earth. The increase in solar UV-radiation at environmental levels, due to depletion of the stratospheric ozone layer, highlights serious issues of social concern. This becomes still more dramatic in tropical and subtropical regions where radiation-intensity is still higher. Thus, there is the need to evaluate the harmful effects of solar UV-radiation on the DNA molecule as a basis for assessing the risks involved for human health, biological productivity and ecosystems. In order to evaluate the profile of DNA damage induced by this form of radiation and its genotoxic effects, plasmid DNA samples were exposed to artificial-UV lamps and directly to sunlight. The induction of cyclobutane pyrimidine dimer photoproducts (CPDs) and oxidative DNA damage in these molecules were evaluated by means of specific DNA repair enzymes. On the other hand, the biological effects of such lesions were determined through the analysis of the DNA inactivation rate and mutation frequency, after replication of the damaged pCMUT vector in an Escherichia coliMBL50 strain. The results indicated the induction of a significant number of CPDs after exposure to increasing doses of UVC, UVB, UVA radiation and sunlight. Interestingly, these photoproducts are those lesions that better correlate with plasmid inactivation as well as mutagenesis, and the oxidative DNA damages induced present very low correlation with these effects. The results indicated that DNA photoproducts play the main role in the induction of genotoxic effects by artificial UV-radiation sources and sunlight.

  7. Carcinogenic risks associated with radiation pollution. [UV radiation, sunlight

    Energy Technology Data Exchange (ETDEWEB)

    Latarjet, R.

    1976-01-01

    The cancerogenic pollution by non-ionizing radiations is limited to the case of solar ultraviolet, whose activity at ground level may be increased as a consequence of the stratospheric depletion of ozone, produced by certain chemical pollutants: nitrogen oxides from supersonic aircrafts, freon. As regards ionizing radiations, the discussion is focused on the fundamental problem of the threshold, and on the means by which one may obtain some quantitative data related to carcinogenesis by small radiation doses in man. A new concept, that of a practical threshold, is proposed. A theory which links radiocancerogenesis, as well as chemical cancerogenesis, to errors produced in the repair of lesions in the DNA is discussed. The rads-equivalent project for chemical mutagens and carcinogens is described.

  8. Sunlight, ultraviolet radiation, vitamin D and skin cancer: how much sunlight do we need?

    Science.gov (United States)

    Holick, Michael F

    2014-01-01

    Vitamin D is the sunshine vitamin for good reason. During exposure to sunlight, the UV B photons enter the skin and photolyze 7-dehydrocholesterol to previtamin D3 which in turn is isomerized by the body's temperature to vitamin D3. Most humans have depended on sun for their vitamin D requirement. Skin pigment, sunscreen use, aging, time of day, season and latitude dramatically affect previtamin 13 synthesis. Vitamin D deficiency was thought to have been conquered, but it is now recognized that more than 50% of the world's population is at risk for vitamin D deficiency. This deficiency is in part due to the inadequate fortification of foods with vitamin D and the misconception that a healthy diet contains an adequate amount of vitamin D. Vitamin D deficiency causes growth retardation and rickets in children and will precipitate and exacerbate osteopenia, osteoporosis and increase risk of fracture in adults. The vitamin D deficiency has been associated pandemic with other serious consequences including increased risk of common cancers, autoimmune diseases, infectious diseases and cardiovascular disease. There needs to be a renewed appreciation of the beneficial effect of moderate sunlight for providing all humans with their vitamin D requirement for health.

  9. 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.

  10. 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

  11. Radiation Damage of Quartz Fibers

    CERN Document Server

    Hagopian, V

    1999-01-01

    Quartz fibers are used in high energy physics experiments as the active medium in high radiation area calorimetry. Quartz fibers are also used in the transmission of optical signals. Even though quartz does not damage by moderate amounts of irradiation, the clad of the fibers and the protective coating ( buffer) do damage reducing light transmission. Various types of quartz fibers have been irradiated and measured for light transmission. The most radiation hard quartz fibers are those with quartz clad and aluminum buffer.

  12. 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...

  13. Sunlight-exposed biofilm microbial communities are naturally resistant to chernobyl ionizing-radiation levels.

    Science.gov (United States)

    Ragon, Marie; Restoux, Gwendal; Moreira, David; Møller, Anders Pape; López-García, Purificación

    2011-01-01

    The Chernobyl accident represents a long-term experiment on the effects of exposure to ionizing radiation at the ecosystem level. Though studies of these effects on plants and animals are abundant, the study of how Chernobyl radiation levels affect prokaryotic and eukaryotic microbial communities is practically non-existent, except for a few reports on human pathogens or soil microorganisms. Environments enduring extreme desiccation and UV radiation, such as sunlight exposed biofilms could in principle select for organisms highly resistant to ionizing radiation as well. To test this hypothesis, we explored the diversity of microorganisms belonging to the three domains of life by cultivation-independent approaches in biofilms developing on concrete walls or pillars in the Chernobyl area exposed to different levels of radiation, and we compared them with a similar biofilm from a non-irradiated site in Northern Ireland. Actinobacteria, Alphaproteobacteria, Bacteroidetes, Acidobacteria and Deinococcales were the most consistently detected bacterial groups, whereas green algae (Chlorophyta) and ascomycete fungi (Ascomycota) dominated within the eukaryotes. Close relatives to the most radio-resistant organisms known, including Rubrobacter species, Deinococcales and melanized ascomycete fungi were always detected. The diversity of bacteria and eukaryotes found in the most highly irradiated samples was comparable to that of less irradiated Chernobyl sites and Northern Ireland. However, the study of mutation frequencies in non-coding ITS regions versus SSU rRNA genes in members of a same actinobacterial operational taxonomic unit (OTU) present in Chernobyl samples and Northern Ireland showed a positive correlation between increased radiation and mutation rates. Our results show that biofilm microbial communities in the most irradiated samples are comparable to non-irradiated samples in terms of general diversity patterns, despite increased mutation levels at the single

  14. Bacterial growth in humic waters exposed to UV-radiation and simulated sunlight

    DEFF Research Database (Denmark)

    Corin, N.; Backlund, P.; Wiklund, T.

    1998-01-01

    Sterile filtered (0.45 mu m) humic lake water was exposed to simulated sunlight (300-800 nm) or W-radiation (254 run)for various periods of times and the dissolved organic carbon content, absorbance at 254 and 460 nm and PH were recorded. The irradiated water was inoculated with a natural bacterial...... in an increased availability of the dissolved organic material as bacterial substrate. No inhibitory effect on the bacterial growth, due to the presence of toxic organic reaction products, was observed. (C) 1998 Published by Elsevier Science Ltd....

  15. Radiation damage in silicon detectors

    CERN Document Server

    Lindström, G

    2003-01-01

    Radiation damage effects in silicon detectors under severe hadron and gamma-irradiation are surveyed, focusing on bulk effects. Both macroscopic detector properties (reverse current, depletion voltage and charge collection) as also the underlying microscopic defect generation are covered. Basic results are taken from the work done in the CERN-RD48 (ROSE) collaboration updated by results of recent work. Preliminary studies on the use of dimerized float zone and Czochralski silicon as detector material show possible benefits. An essential progress in the understanding of the radiation-induced detector deterioration had recently been achieved in gamma irradiation, directly correlating defect analysis data with the macroscopic detector performance.

  16. The relationship between long-term sunlight radiation and cognitive decline in the REGARDS cohort study

    Science.gov (United States)

    Kent, Shia T.; Kabagambe, Edmond K.; Wadley, Virginia G.; Howard, Virginia J.; Crosson, William L.; Al-Hamdan, Mohammad Z.; Judd, Suzanne E.; Peace, Fredrick; McClure, Leslie A.

    2014-04-01

    Sunlight may be related to cognitive function through vitamin D metabolism or circadian rhythm regulation. The analysis presented here sought to test whether ground and satellite measures of solar radiation are associated with cognitive decline. The study used a 15-year residential history merged with satellite and ground monitor data to determine sunlight (solar radiation) and air temperature exposure for a cohort of 19,896 cognitively intact black and white participants aged 45+ from the 48 contiguous United States. Exposures of 15, 10, 5, 2, and 1-year were used to predict cognitive status at the most recent assessment in logistic regression models; 1-year insolation and maximum temperatures were chosen as exposure measures. Solar radiation interacted with temperature, age, and gender in its relationships with incident cognitive impairment. After adjustment for covariates, the odds ratio (OR) of cognitive decline for solar radiation exposure below the median vs above the median in the 3rd tertile of maximum temperatures was 1.88 (95 % CI: 1.24, 2.85), that in the 2nd tertile was 1.33 (95 % CI: 1.09, 1.62), and that in the 1st tertile was 1.22 (95 % CI: 0.92, 1.60). We also found that participants under 60 years old had an OR = 1.63 (95 % CI: 1.20, 2.22), those 60-80 years old had an OR = 1.18 (95 % CI: 1.02, 1.36), and those over 80 years old had an OR = 1.05 (0.80, 1.37). Lastly, we found that males had an OR = 1.43 (95 % CI: 1.22, 1.69), and females had an OR = 1.02 (0.87, 1.20). We found that lower levels of solar radiation were associated with increased odds of incident cognitive impairment.

  17. Sunlight-Exposed Biofilm Microbial Communities Are Naturally Resistant to Chernobyl Ionizing-Radiation Levels

    Science.gov (United States)

    Ragon, Marie; Restoux, Gwendal; Moreira, David; Møller, Anders Pape; López-García, Purificación

    2011-01-01

    Background The Chernobyl accident represents a long-term experiment on the effects of exposure to ionizing radiation at the ecosystem level. Though studies of these effects on plants and animals are abundant, the study of how Chernobyl radiation levels affect prokaryotic and eukaryotic microbial communities is practically non-existent, except for a few reports on human pathogens or soil microorganisms. Environments enduring extreme desiccation and UV radiation, such as sunlight exposed biofilms could in principle select for organisms highly resistant to ionizing radiation as well. Methodology/Principal Findings To test this hypothesis, we explored the diversity of microorganisms belonging to the three domains of life by cultivation-independent approaches in biofilms developing on concrete walls or pillars in the Chernobyl area exposed to different levels of radiation, and we compared them with a similar biofilm from a non-irradiated site in Northern Ireland. Actinobacteria, Alphaproteobacteria, Bacteroidetes, Acidobacteria and Deinococcales were the most consistently detected bacterial groups, whereas green algae (Chlorophyta) and ascomycete fungi (Ascomycota) dominated within the eukaryotes. Close relatives to the most radio-resistant organisms known, including Rubrobacter species, Deinococcales and melanized ascomycete fungi were always detected. The diversity of bacteria and eukaryotes found in the most highly irradiated samples was comparable to that of less irradiated Chernobyl sites and Northern Ireland. However, the study of mutation frequencies in non-coding ITS regions versus SSU rRNA genes in members of a same actinobacterial operational taxonomic unit (OTU) present in Chernobyl samples and Northern Ireland showed a positive correlation between increased radiation and mutation rates. Conclusions/Significance Our results show that biofilm microbial communities in the most irradiated samples are comparable to non-irradiated samples in terms of general

  18. Sunlight-exposed biofilm microbial communities are naturally resistant to chernobyl ionizing-radiation levels.

    Directory of Open Access Journals (Sweden)

    Marie Ragon

    Full Text Available BACKGROUND: The Chernobyl accident represents a long-term experiment on the effects of exposure to ionizing radiation at the ecosystem level. Though studies of these effects on plants and animals are abundant, the study of how Chernobyl radiation levels affect prokaryotic and eukaryotic microbial communities is practically non-existent, except for a few reports on human pathogens or soil microorganisms. Environments enduring extreme desiccation and UV radiation, such as sunlight exposed biofilms could in principle select for organisms highly resistant to ionizing radiation as well. METHODOLOGY/PRINCIPAL FINDINGS: To test this hypothesis, we explored the diversity of microorganisms belonging to the three domains of life by cultivation-independent approaches in biofilms developing on concrete walls or pillars in the Chernobyl area exposed to different levels of radiation, and we compared them with a similar biofilm from a non-irradiated site in Northern Ireland. Actinobacteria, Alphaproteobacteria, Bacteroidetes, Acidobacteria and Deinococcales were the most consistently detected bacterial groups, whereas green algae (Chlorophyta and ascomycete fungi (Ascomycota dominated within the eukaryotes. Close relatives to the most radio-resistant organisms known, including Rubrobacter species, Deinococcales and melanized ascomycete fungi were always detected. The diversity of bacteria and eukaryotes found in the most highly irradiated samples was comparable to that of less irradiated Chernobyl sites and Northern Ireland. However, the study of mutation frequencies in non-coding ITS regions versus SSU rRNA genes in members of a same actinobacterial operational taxonomic unit (OTU present in Chernobyl samples and Northern Ireland showed a positive correlation between increased radiation and mutation rates. CONCLUSIONS/SIGNIFICANCE: Our results show that biofilm microbial communities in the most irradiated samples are comparable to non-irradiated samples in

  19. 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.

  20. 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

  1. No indications for an ultraviolet B radiation induced decline of immunological parameters after sunlight exposure among HIV infected homosexual men

    NARCIS (Netherlands)

    Maas J; Termorshuizen F; Geskus RB; Coutinho RA; Loveren H van; GG&GD Amsterdam; LPI

    2000-01-01

    Whether sunlight (especially ultraviolet B radiation: UVB) exposure is harmful to the cellular immunity of HIV infected individuals and whether it is associated with an accelerated progression toward AIDS is still under debate. Among HIV+ homosexual participants of the Amsterdam Cohort Study, the de

  2. No indications for an ultraviolet B radiation induced decline of immunological parameters after sunlight exposure among HIV infected homosexual men

    NARCIS (Netherlands)

    Maas J; Termorshuizen F; Geskus RB; Coutinho RA; Loveren H van; GG&GD Amsterdam; LPI

    2000-01-01

    Whether sunlight (especially ultraviolet B radiation: UVB) exposure is harmful to the cellular immunity of HIV infected individuals and whether it is associated with an accelerated progression toward AIDS is still under debate. Among HIV+ homosexual participants of the Amsterdam Cohort Study, the de

  3. Photosensitized mefloquine induces ROS-mediated DNA damage and apoptosis in keratinocytes under ambient UVB and sunlight exposure.

    Science.gov (United States)

    Yadav, Neera; Dwivedi, Ashish; Mujtaba, Syed Faiz; Verma, Ankit; Chaturvedi, Rajnish; Ray, Ratan Singh; Singh, Gajendra

    2014-10-01

    The present study illustrates the photosensitizing behavior of mefloquine (MQ) in human skin keratinocytes under ambient doses of UVB and sunlight exposure. Photochemically, MQ generated reactive oxygen species superoxide radical, hydroxyl radical, and singlet oxygen through type I and type II photodynamic reactions, respectively, which caused photooxidative damage to DNA and formed localized DNA lesions cyclobutane pyrimidine dimers. Photosensitized MQ reduced the viability of keratinocytes to 25 %. Significant level of intracellular reactive oxygen species (ROS) generation was estimated through fluorescence probe DCF-H2. Increased apoptotic cells were evident through AO/EB staining and phosphatidyl serine translocation in cell membrane. Single-stranded DNA damage was marked through single-cell gel electrophoresis. Mitochondrial membrane depolarization and lysosomal destabilization were evident. Upregulation of Bax and p21 and downregulation of Bcl-2 genes and corresponding protein levels supported apoptotic cell death of keratinocyte cells. Cyclobutane pyrimidine dimers (CPDs) were confirmed through immunofluorescence. In addition, hallmarks of apoptosis and G2/M phase cell cycle arrest were confirmed through flow cytometry analysis. Our findings suggest that MQ may damage DNA and produce DNA lesions which may induce differential biological responses in the skin on brief exposure to UVB and sunlight.

  4. [Mechanisms of electromagnetic radiation damaging male reproduction].

    Science.gov (United States)

    Xue, Lei; Chen, Hao-Yu; Wang, Shui-Ming

    2012-08-01

    More and more evidence from over 50 years of researches on the effects of electromagnetic radiation on male reproduction show that a certain dose of electromagnetic radiation obviously damages male reproduction, particularly the structure and function of spermatogenic cells. The mechanisms of the injury may be associated with energy dysmetabolism, lipid peroxidation, abnormal expressions of apoptosis-related genes and proteins, and DNA damage.

  5. 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.

  6. Radiation damage in rat kidney microvasculature.

    Science.gov (United States)

    Nelson, A C; Shah-Yukich, A; Babayan, R

    1984-01-01

    Scanning electron microscopy (SEM) combined with a specialized polymer injection casting technique permits the analysis of radiation induced damage in rat kidney glomeruli. A lead shielding device is constructed to enable the irradiation of the living rat left kidney, while the remainder of the animal is shielded from the dose, the right kidney serves as a control. The source of radiation is 137Cs which produces 0.66 MeV gamma-rays to achieve a kidney dose of 100 rad and 5000 rad in these experiments. Radiation damage to kidney glomeruli is assessed at intervals of 0, 1, 3 and 7 days post-irradiation at the two dose levels. It is found that radiation damage to kidney glomeruli is expressed morphologically at 7 days post-irradiation at the 100 rad dose level, while glomerular damage is apparent as early as 3 days post-irradiation at the 5000 rad dose level. Moreover, by 7 days post-irradiation with a 5000 rad dose, the kidney glomerulus thoroughly degenerates to a leaky fused mass of vessels. From a morphological viewpoint, kidney glomeruli are significantly more sensitive to radiation than surrounding vasculature. The methods developed here for assessment of radiation damage are highly repeatable and could serve as a standard technique in radiobiology.

  7. Effect of Sunlight Radiation on the Growth and Chemical Constituents of Salvia plebeia R.Br.

    Directory of Open Access Journals (Sweden)

    Hyun-Jae Jang

    2017-08-01

    Full Text Available This study investigated the chemical composition changes of Salvia plebeia R.Br. cultivated under different light sources, including florescent light and sunlight. The plants were exposed to fluorescent light for four months and sunlight and then examined for the next 5–7 months. Plants were harvested monthly during the seven months, and we examined whether the difference in light source affected the phenolic and flavonoid contents and antioxidant activity. A simple and reliable HPLC method using a PAH C18 column was applied for the quantitative analysis of two triterpenoids from the S. plebeia groups. Oleanolic acid (OA and ursolic acid (UA showed good linearity (R2 > 0.9999 within the test ranges (0.005–0.05 mg/mL, and the average percentage recoveries of the OA and UA were 95.1–104.8% and 97.2–107.1%, respectively. The intra- and inter-day relative standard deviations (RSDs were less than 2.0%. After exposure to sunlight, the phenolic contents, including rosmarinic acid, showed a reduced tendency, whereas the flavonoid contents, including homoplantaginin and luteolin 7-glucoside, were increased. The content of the triterpenoids also showed an increased tendency under sunlight irradiation, but the variance was not larger than those of the phenolic and flavonoid contents. Among experimental groups, the group harvested at six months, having been exposed to sunlight for two months, showed the most potent antioxidant activity. Therefore, these results showed that the chemical composition and antioxidant activities of S. plebeia R.Br. was affected from environmental culture conditions, such as light source. Our studies will be useful for the development of functional materials using S. plebeia R.Br.

  8. Effect of Sunlight Radiation on the Growth and Chemical Constituents of Salvia plebeia R.Br.

    Science.gov (United States)

    Jang, Hyun-Jae; Lee, Seung-Jae; Kim, Cha Young; Hwang, Joo Tae; Choi, Jung Ho; Park, Jee Hun; Lee, Seung Woong; Rho, Mun-Chual

    2017-08-01

    This study investigated the chemical composition changes of Salvia plebeia R.Br. cultivated under different light sources, including florescent light and sunlight. The plants were exposed to fluorescent light for four months and sunlight and then examined for the next 5-7 months. Plants were harvested monthly during the seven months, and we examined whether the difference in light source affected the phenolic and flavonoid contents and antioxidant activity. A simple and reliable HPLC method using a PAH C18 column was applied for the quantitative analysis of two triterpenoids from the S. plebeia groups. Oleanolic acid (OA) and ursolic acid (UA) showed good linearity (R² > 0.9999) within the test ranges (0.005-0.05 mg/mL), and the average percentage recoveries of the OA and UA were 95.1-104.8% and 97.2-107.1%, respectively. The intra- and inter-day relative standard deviations (RSDs) were less than 2.0%. After exposure to sunlight, the phenolic contents, including rosmarinic acid, showed a reduced tendency, whereas the flavonoid contents, including homoplantaginin and luteolin 7-glucoside, were increased. The content of the triterpenoids also showed an increased tendency under sunlight irradiation, but the variance was not larger than those of the phenolic and flavonoid contents. Among experimental groups, the group harvested at six months, having been exposed to sunlight for two months, showed the most potent antioxidant activity. Therefore, these results showed that the chemical composition and antioxidant activities of S. plebeia R.Br. was affected from environmental culture conditions, such as light source. Our studies will be useful for the development of functional materials using S. plebeia R.Br.

  9. 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.

  10. Nanofoams Response to Radiation Damage

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Engang [Los Alamos National Laboratory; Serrano De Caro, Magdalena [Los Alamos National Laboratory; Wang, Yongqiang [Los Alamos National Laboratory; Nastasi, Michael [Nebraska Center for Energy Sciences Research, University of Nebraska-Lincoln, NE 68508; Zepeda-Ruiz, Luis [PLS, Lawrence Livermore National Laboratory, Livermore, CA 94551; Bringa, Eduardo M. [CONICET and Inst. Ciencias Basicas, Universidad Nacional de Cuyo, Mendoza, 5500 Argentina; Baldwin, Jon K. [Los Alamos National Laboratory; Caro, Jose A. [Los Alamos National Laboratory

    2012-07-30

    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.

  11. Radiation damage effect on avalanche photodiodes

    CERN Document Server

    Baccaro, S; Cavallari, F; Da Ponte, V; Deiters, K; Denes, P; Diemoz, M; Kirn, Th; Lintern, A L; Longo, E; Montecchi, M; Musienko, Y; Pansart, J P; Renker, D; Reucroft, S; Rosi, G; Rusack, R; Ruuska, D; Stephenson, R; Torbet, M J

    1999-01-01

    Avalanche Photodiodes have been chosen as photon sensors for the electromagnetic calorimeter of the CMS experiment at the LHC. These sensors should operate in the 4T magnetic field of the experiment. Because of the high neutron radiation in the detector extensive studies have been done by the CMS collaboration on the APD neutron radiation damage. The characteristics of these devices after irradiation have been analized, with particular attention to the quantum efficiency and the dark current. The recovery of the radiation induced dark current has been studied carefully at room temperature and at slightly lower and higher temperatures. The temperature dependence of the defects decay-time has been evaluated.

  12. 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.)

  13. Ion-biomolecule interactions and radiation damage

    NARCIS (Netherlands)

    Schlathölter, T.A.; Alvarado Chacon, F.; Hoekstra, R.A.

    2005-01-01

    Ionization and fragmentation of DNA and its constituents is it primary step in biological radiation damage. In this paper we investigate the response of nucleobases upon interaction with keV singly and multiply charged ions. The dependence of ionization and fragmentation on ion atomic number Z, char

  14. The Status of Radiation Damage Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Strachan, Denis M.; Scheele, Randall D.; Icenhower, Jonathan P.; Kozelisky, Anne E.; Sell, Richard L.; Legore, Virginia L.; Schaef, Herbert T.; O' Hara, Matthew J.; Brown, Christopher F.; Buchmiller, William C.

    2001-11-20

    Experiments have been on-going for about two years to determine the effects that radiation damage have on the physical and chemical properties of candidate titanate ceramics for the immobilization of plutonium. We summarize the results of these experiments in this document.

  15. 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.

  16. Calculation of Radiation Damage in SLAC Targets

    Energy Technology Data Exchange (ETDEWEB)

    Wirth, B D; Monasterio, P; Stein, W

    2008-04-03

    Ti-6Al-4V alloys are being considered as a positron producing target in the Next Linear Collider, with an incident photon beam and operating temperatures between room temperature and 300 C. Calculations of displacement damage in Ti-6Al-4V alloys have been performed by combining high-energy particle FLUKA simulations with SPECTER calculations of the displacement cross section from the resulting energy-dependent neutron flux plus the displacements calculated from the Lindhard model from the resulting energy-dependent ion flux. The radiation damage calculations have investigated two cases, namely the damage produced in a Ti-6Al-4V SLAC positron target where the irradiation source is a photon beam with energies between 5 and 11 MeV. As well, the radiation damage dose in displacements per atom, dpa, has been calculated for a mono-energetic 196 MeV proton irradiation experiment performed at Brookhaven National Laboratory (BLIP experiment). The calculated damage rate is 0.8 dpa/year for the Ti-6Al-4V SLAC photon irradiation target, and a total damage exposure of 0.06 dpa in the BLIP irradiation experiment. In both cases, the displacements are predominantly ({approx}80%) produced by recoiling ions (atomic nuclei) from photo-nuclear collisions or proton-nuclear collisions, respectively. Approximately 25% of the displacement damage results from the neutrons in both cases. Irradiation effects studies in titanium alloys have shown substantial increases in the yield and ultimate strength of up to 500 MPa and a corresponding decrease in uniform ductility for neutron and high energy proton irradiation at temperatures between 40 and 300 C. Although the data is limited, there is an indication that the strength increases will saturate by doses on the order of a few dpa. Microstructural investigations indicate that the dominant features responsible for the strength increases were dense precipitation of a {beta} (body-centered cubic) phase precipitate along with a high number density

  17. 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 \

  18. 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...

  19. DNA damage and repair in plants under ultraviolet and ionizing radiations.

    Science.gov (United States)

    Gill, Sarvajeet S; Anjum, Naser A; Gill, Ritu; Jha, Manoranjan; Tuteja, Narendra

    2015-01-01

    Being sessile, plants are continuously exposed to DNA-damaging agents present in the environment such as ultraviolet (UV) and ionizing radiations (IR). Sunlight acts as an energy source for photosynthetic plants; hence, avoidance of UV radiations (namely, UV-A, 315-400 nm; UV-B, 280-315 nm; and UV-C, exposure, plants make use of several DNA repair mechanisms. In the light of recent breakthrough, the current minireview (a) introduces UV/IR and overviews UV/IR-mediated DNA damage products and (b) critically discusses the biochemistry and genetics of major pathways responsible for the repair of UV/IR-accrued DNA damage. The outcome of the discussion may be helpful in devising future research in the current context.

  20. Radiation Damage in Polarized Ammonia Solids

    CERN Document Server

    Slifer, K

    2007-01-01

    Solid NH3 and ND3 provide a highly polarizable, radiation resistant source of polarized protons and deuterons and have been used extensively in high luminosity experiments investigating the spin structure of the nucleon. Over the past twenty years, the UVA polarized target group has been instrumental in producing and polarizing much of the material used in these studies, and many practical considerations have been learned in this time. In this discussion, we analyze the polarization performance of the solid ammonia targets used during the recent JLab Eg4 run. Topics include the rate of polarization decay with accumulated charge, the annealing procedure for radiation damaged targets to recover polarization, and the radiation induced change in optimum microwave frequency used to polarize the sample. We also discuss the success we have had in implementing frequency modulation of the polarizing microwave frequency.

  1. Radiation damage of insulating crystals induced by electronic excitation

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Noriaki

    1988-05-01

    A review is given on radiation damage of insulating crystals arising from energy imparted to solids into electronic excitation. Emphasis is placed in describing the mechanism. The role of the exciton-phonon interaction in the production of radiation damage is described and the radiation damage processes in a few typical insulators such as alkali halides, alkali earth fluorides and silicon dioxide are described.

  2. Disinfection of Airborne Organisms by Ultraviolet-C Radiation and Sunlight

    Science.gov (United States)

    2012-07-01

    cytoplasm contain UV radiation-absorbing proteins. 2. The majority of bacterial spores identified at high altitudes contain pigments such as...3 4. BACTERIAL ENDOSPORES...10 6. Single (left) and approximately 4 µm clustered (right) bacterial spores ...............16 7. A

  3. 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.

  4. Anatomical exposure patterns of skin to sunlight: relative contributions of direct, diffuse and reflected ultraviolet radiation.

    Science.gov (United States)

    Vernez, D; Milon, A; Vuilleumier, L; Bulliard, J-L

    2012-08-01

    The dose-response between ultraviolet (UV) exposure patterns and skin cancer occurrence is not fully understood. Sun-protection messages often focus on acute exposure, implicitly assuming that direct UV radiation is the key contributor to the overall UV exposure. However, little is known about the relative contribution of the direct, diffuse and reflected radiation components. To investigate solar UV exposure patterns at different body sites with respect to the relative contribution of the direct, diffuse and reflected radiation. A three-dimensional numerical model was used to assess exposure doses for various body parts and exposure scenarios of a standing individual (static and dynamic postures). The model was fed with erythemally weighted ground irradiance data for the year 2009 in Payerne, Switzerland. A year-round daily exposure (08:00-17:00 h) without protection was assumed. For most anatomical sites, mean daily doses were high (typically 6.2-14.6 standard erythemal doses) and exceeded the recommended exposure values. Direct exposure was important during specific periods (e.g. midday during summer), but contributed moderately to the annual dose, ranging from 15% to 24% for vertical and horizontal body parts, respectively. Diffuse irradiation explained about 80% of the cumulative annual exposure dose. Acute diffuse exposures were also observed during cloudy summer days. The importance of diffuse UV radiation should not be underestimated when advocating preventive measures. Messages focused on avoiding acute direct exposures may be of limited efficiency to prevent skin cancers associated with chronic exposure. © 2012 The Authors. BJD © 2012 British Association of Dermatologists.

  5. Effect of grape bunch sunlight exposure and UV radiation on phenolics and volatile composition of Vitis vinifera L. cv. Pinot noir wine.

    Science.gov (United States)

    Song, Jianqiang; Smart, Richard; Wang, Hua; Dambergs, Bob; Sparrow, Angela; Qian, Michael C

    2015-04-15

    The effect of canopy leaf removal and ultraviolet (UV) on Pinot noir grape and wine composition was investigated in this study. Limited basal leaf removal in the fruit zone was conducted, compared to shaded bunches. The UV exposure was controlled using polycarbonate screens to block UV radiation, and acrylic screens to pass the UV. The results showed that bunch sunlight and UV exposure significantly increased the Brix and pH in the grape juice, and increased substantially wine colour density, anthocyanins, total pigment, total phenolics and tannin content. Bunch sunlight and UV exposure affected terpene alcohols, C13-norisprenoids and other volatile composition of the wine differently. Sunlight exposure and UV resulted in increase of nerol, geraniol and citronellol but not linalool. Sunlight exposure slightly increased the concentration of β-ionone, but the increase was not statistically significant for UV treatment. Neither sunlight nor UV treatment showed any impact on the concentration of β-damascenone. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. 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.

  7. Radiation damage in zircon and monazite

    Energy Technology Data Exchange (ETDEWEB)

    Meldrum, A.; Boatner, L.A. [Oak Ridge National Lab., TN (United States). Solid state Div.; Weber, W.J. [Pacific Northwest National Lab., Richland, WA (United States); Ewing, R.C. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Nuclear Engineering and Radiological Sciences

    1998-07-01

    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 {alpha}-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. Particle fluence measurements by activation technique for radiation damage studies

    CERN Document Server

    León-Florián, E; Furetta, C; Leroy, Claude

    1995-01-01

    High-level radiation environment can produce radiation damage in detectors and their associate electronic components. The establishment of a correlation between damage, irradiation level and absorbed dose requires a precise measurement of the fluence of particles causing the damage. The activation technique is frequently used for performing particle fluence measurements. A review of this technique is presented.

  9. 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.

  10. 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.

  11. Simulation of radiation damage in gadolinium pyrochlores

    Science.gov (United States)

    Todorov, Ilian T.; Purton, John A.; Allan, Neil L.; Dove, Martin T.

    2006-02-01

    We report molecular dynamics simulations of the production of radiation cascades in pyrochlores. We consider the apparently similar systems Gd2Ti2O7, Gd2Zr2O7 and Gd2Pb2O7, the first two of which have been put forward as potential materials for high-level radioactive waste storage. The effects of changing the mass of the 'primary knock-on' atom are also examined and we investigate whether the change in behaviour from Ti to Zr to Pb is largely due to the mass or the size difference between the elements. Problems associated with analysing the cascades and the damage created are discussed. There are clear differences between the three compounds. The simulations see no direct amorphization but rather a transition to the fluorite structure which is more pronounced for the Zr and Pb compounds than the Ti system. Underlying chemical trends are examined.

  12. The study of radiation damage of EPROM 2764 memory

    Directory of Open Access Journals (Sweden)

    Domanski Grzegorz

    2016-01-01

    Full Text Available A simple statistical theory of radiation damage of semiconductor memory has been constructed. The radiation damage of EPROM memory has been investigated. The measured number of damaged bytes is significantly lower than the expected number resulting from the purely random distribution of the damaged bits. In this way it has been proven that there is a correlation between the failures of individual memory bits which are located in the same byte.

  13. Radiation damage of polyethylene exposed in the stratosphere at an altitude of 40 km

    CERN Document Server

    Kondyurin, Alexey; Bilek, Marcela

    2011-01-01

    Low Density Polyethylene (LDPE) films were exposed at an altitude of 40 km over a 3 day NASA stratospheric balloon mission from Alice Springs, Australia. The radiation damage, oxidation and nitration in the LDPE films exposed in stratosphere were measured using ESR, FTIR and XPS spectroscopy. The results were compared with those from samples stored on the ground and exposed in a laboratory plasma. The types of free radicals, unsaturated hydrocarbon groups, oxygen-containing and nitrogen-containing groups in LDPE film exposed in the stratosphere and at the Earth's surface are different. The radiation damage in films exposed in the stratosphere are observed in the entire film due to the penetration of high energy cosmic rays through their thickness, while the radiation damage in films exposed on the ground is caused by sunlight penetrating into only a thin surface layer. A similarly thin layer of the film is damaged by exposure to plasma due to the low energy of the plasma particles. The intensity of oxidation ...

  14. DNA Damage and Repair in Plants under Ultraviolet and Ionizing Radiations

    Directory of Open Access Journals (Sweden)

    Sarvajeet S. Gill

    2015-01-01

    Full Text Available Being sessile, plants are continuously exposed to DNA-damaging agents present in the environment such as ultraviolet (UV and ionizing radiations (IR. Sunlight acts as an energy source for photosynthetic plants; hence, avoidance of UV radiations (namely, UV-A, 315–400 nm; UV-B, 280–315 nm; and UV-C, <280 nm is unpreventable. DNA in particular strongly absorbs UV-B; therefore, it is the most important target for UV-B induced damage. On the other hand, IR causes water radiolysis, which generates highly reactive hydroxyl radicals (OH• and causes radiogenic damage to important cellular components. However, to maintain genomic integrity under UV/IR exposure, plants make use of several DNA repair mechanisms. In the light of recent breakthrough, the current minireview (a introduces UV/IR and overviews UV/IR-mediated DNA damage products and (b critically discusses the biochemistry and genetics of major pathways responsible for the repair of UV/IR-accrued DNA damage. The outcome of the discussion may be helpful in devising future research in the current context.

  15. Radiation Damage in Electronic Memory Devices

    OpenAIRE

    Irfan Fetahović; Milić Pejović; Miloš Vujisić

    2013-01-01

    This paper investigates the behavior of semiconductor memories exposed to radiation in order to establish their applicability in a radiation environment. The experimental procedure has been used to test radiation hardness of commercial semiconductor memories. Different types of memory chips have been exposed to indirect ionizing radiation by changing radiation dose intensity. The effect of direct ionizing radiation on semiconductor memory behavior has been analyzed by using Monte Carlo simula...

  16. Chemistry of radiation damage to wire chambers

    Energy Technology Data Exchange (ETDEWEB)

    Wise, J.

    1992-08-01

    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 CF{sub 4}/iC{sub 4}H{sub 10} 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 CF{sub 4}-rich gases. A four-part model considering plasma polymerization of the hydrocarbon, etching of wire deposits by CF{sub 4}, acceleration of deposition processes in strongly etching environments, and reactivity of the wire surface is developed to understand anode wire aging in CF{sub 4}/iC{sub 4}H{sub 10} 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/C{sub 2}H{sub 6}. Apparent loss of gain is explained by attachment of primary electrons to a continuously increasing concentration of Freon 11 (CCl{sub 3}F) 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.

  17. 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)

  18. Radiation Damage in Electronic Memory Devices

    Directory of Open Access Journals (Sweden)

    Irfan Fetahović

    2013-01-01

    Full Text Available This paper investigates the behavior of semiconductor memories exposed to radiation in order to establish their applicability in a radiation environment. The experimental procedure has been used to test radiation hardness of commercial semiconductor memories. Different types of memory chips have been exposed to indirect ionizing radiation by changing radiation dose intensity. The effect of direct ionizing radiation on semiconductor memory behavior has been analyzed by using Monte Carlo simulation method. Obtained results show that gamma radiation causes decrease in threshold voltage, being proportional to the absorbed dose of radiation. Monte Carlo simulations of radiation interaction with material proved to be significant and can be a good estimation tool in probing semiconductor memory behavior in radiation environment.

  19. 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…

  20. Taxicab tipping and sunlight

    Science.gov (United States)

    2017-01-01

    Does the level of sunlight affect the tipping percentage in taxicab rides in New York City? We examined this question using data on 13.82 million cab rides from January to October in 2009 in New York City combined with data on hourly levels of solar radiation. We found a small but statistically significant positive relationship between sunlight and tipping, with an estimated tipping increase of 0.5 to 0.7 percentage points when transitioning from a dark sky to full sunshine. The findings are robust to two-way clustering of standard errors based on hour-of-the-day and day-of-the-year and controlling for day-of-the-year, month-of-the-year, cab driver fixed effects, weather conditions, and ride characteristics. The NYC cab ride context is suitable for testing the association between sunlight and tipping due to the largely random assignment of riders to drivers, direct exposure to sunlight, and low confounding from variation in service experiences. PMID:28594917

  1. 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.

  2. Advances in Researches of Low Temperature and Cold Damage Prevention Technology in Sunlight Greenhouse%日光温室低温冷冻害防御技术研究进展

    Institute of Scientific and Technical Information of China (English)

    董思瑶; 王海荣

    2015-01-01

    Low temperature and cold damage prevention is an important subject for the safe production of sunlight green-house. The advances in the researches on the causes of low temperature and cold damage in the sunlight greenhouse as well as the technology for preventing it are discussed. The technology of increasing temperature automatically in the Internet of Things-based sunlight greenhouse is put forward to provide a basis for further research.%低温冷害、冻害防御是日光温室安全生产的重要课题.通过对日光温室低温冷、冻害成因及防御技术的进展研究,提出基于物联网的日光温室自动补温技术,为进一步研究提供基础.

  3. Temperature effects on radiation damage to silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Barberis, E.; Cartiglia, N.; Leslie, J.; Pitzl, D.; Rowe, W.A.; Sadrozinski, H.F.W. (SCIPP, Univ. California, Santa Cruz, CA (United States)); Boissevain, J.G.; Ferguson, P.; Holzscheiter, K.; Kapustinsky, J.S.; Palounek, A.P.T.; Sommer, W.F.; Sondheim, W.E.; Ziock, H.J. (Los Alamos National Lab., NM (United States)); Ellison, J.A.; Fleming, J.K.; Jerger, S.; Joyce, D.; Lietzke, C.; Wimpenny, S.J. (Univ. California, Riverside, CA (United States)); Matthews, J.A.J.; Skinner, D. (Univ. New Mexico, Albuquerque, NM (United States))

    1993-03-01

    Motivated by the large particle fluences anticipated for the SSC and LHC, we are performing a systematic study of radiation damage to silicon microstrip detectors. Here we report radiation effects on detectors cooled to 0deg C (the proposed operating point for a large SSC silicon tracker) including leakage currents and change in depletion voltage. We also present results on the annealing behavior of the radiation damage. Finally, we report results of charge collection measurements of the damaged detectors made with an [sup 241]Am [alpha] source. (orig.).

  4. [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.

  5. Activation and radiation damage in the environment of hadron accelerators

    CERN Document Server

    Kiselev, Daniela

    2013-01-01

    A component which suffers radiation damage usually also becomes radioactive, since the source of activation and radiation damage is the interaction of the material with particles from an accelerator or with reaction products. However, the underlying mechanisms of the two phenomena are different. These mechanisms are described here. Activation and radiation damage can have far-reaching consequences. Components such as targets, collimators, and beam dumps are the first candidates for failure as a result of radiation damage. This means that they have to be replaced or repaired. This takes time, during which personnel accumulate dose. If the dose to personnel at work would exceed permitted limits, remote handling becomes necessary. The remaining material has to be disposed of as radioactive waste, for which an elaborate procedure acceptable to the authorities is required. One of the requirements of the authorities is a complete nuclide inventory. The methods used for calculation of such inventories are presented,...

  6. 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;...

  7. 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.

  8. 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.

  9. 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...

  10. 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.)

  11. 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.)

  12. Bleomycin and radiation-induced lung damage in mice

    Energy Technology Data Exchange (ETDEWEB)

    Collis, C.H.; Down, J.D.; Pearson, A.E.; Steel, G.G. (Institute of Cancer Research, Sutton (UK). Surrey Branch)

    1983-01-01

    Bleomycin-induced lung damage was assessed using both a functional end-point and mortality. The extent of lung damage was found to depend on the schedule, mode of administration and dose of the drug. Greater damage occurred following twice-weekly administration than when the same dose was given as a single injection. Intravenous administration resulted in greater damage than intraperitoneal administration. When bleomycin was given with thoracic irradiation lung damage occurred earlier and at lower radiation doses than with radiation alone. Similar responses were obtained whether bleomycin was given four weeks before, with or four weeks after irradiation. Thus although there was enhanced damage from the combined treatment, there was no evidence of a time-dependent interaction.

  13. QUANTIFYING LOCAL RADIATION-INDUCED LUNG DAMAGE FROM COMPUTED TOMOGRAPHY

    NARCIS (Netherlands)

    Ghobadi, Ghazaleh; Hogeweg, Laurens E.; Faber, Hette; Tukker, Wim G. J.; Schippers, Jacobus M.; Brandenburg, Sytze; Langendijk, Johannes A.; Coppes, Robert P.; van Luijk, Peter

    2010-01-01

    Purpose: Optimal implementation of new radiotherapy techniques requires accurate predictive models for normal tissue complications. Since clinically used dose distributions are nonuniform, local tissue damage needs to be measured and related to local tissue dose. In lung, radiation-induced damage re

  14. Early mechanisms in radiation-induced biological damage

    Energy Technology Data Exchange (ETDEWEB)

    Powers, E.L.

    1983-01-01

    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. (ACR)

  15. Radiation damage of LHCb electromagnetic calorimeter

    CERN Document Server

    Barsuk, S; Kirichenko, V; Korolko, I; Malyshev, S; Rusinov, V Yu; Tarkovski, E

    2000-01-01

    Addressed is an extensive irradiation test program carried on to establish proper design and materials to build electromagnetic calorimeter that matches radiation conditions of the LHCb experiment at CERN. The results obtained are compared with measurements by other groups.

  16. Radiation damage in charge-coupled devices.

    Science.gov (United States)

    Bassler, Niels

    2010-08-01

    Due to their high sensitivity and signal-to-noise ratio, charge-coupled devices (CCDs) have been the preferred optical photon detectors of astronomers for several decades. CCDs are flown in space as the main detection instrument on several well-known missions, such as the Hubble Space Telescope, XMM-Newton or the Cassini Probe. Also, CCDs are frequently used in satellite star trackers which provide attitude information to the satellite orientation system. However, one major drawback is their extreme vulnerability to radiation, which is readily abundant in space. Here, we shall give a brief overview of the radiation effects on CCDs, and mention ways how to mitigate the effects in other ways than merely increase shielding, such as cooling and annealing. As an example, we have investigated the radiation hardness of a particular CCD, the so-called CCD47-20 from Marconi Applied Technologies (now E2V), by exposing it to radiation fields representing the radiation environment found in a highly elliptic orbit crossing the Van-Allen radiation belts. Two engineering-grade CCDs were irradiated with proton beams and photons, and effects of increased bulk dark current, surface dark current and inversion threshold voltage shifts were observed and are quantified.

  17. Radiation damage limitations for the Fermilab Energy Doubler/Saver

    Energy Technology Data Exchange (ETDEWEB)

    Sanger, P.A.

    1977-01-01

    One important factor determining the lifetime of particle accelerators using superconducting magnets is the accumulated radiation damage of the magnet components. Using existing damage studies and a measured correlation between the radiation levels with the beam-off and the beam-on, a reasonable assessment of magnet lifetimes can be made. On the basis of this assessment it is expected that damage to the magnet conductor will not limit the magnet performance. The proper choice of polymeric materials used in the magnet is necessary to avoid frequent refurbishing of the magnets.

  18. Radiation damage in ceramic plasma-facing materials

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Noriaki; Morita, Kenji

    1988-07-01

    The present status of the studies of radiation damage of plasma-facing materials is reviewed. Emphasis is placed on the extent of the understanding in terms of the critical issues for materials in use as plasma interactive components. Understanding of the basic problems of radiation effects, which are important for long term development of fusion reactors, is also emphasized. It is pointed out that for low-Z materials radiation damage by fission neutrons is a good measure of the effects of radiation damage by fusion neutrons. The understanding of the fission neutron damage of major candidate materials is surveyed. Existing data on the effects of transmuted helium gas in beryllium are inferred and the data needs for the He effects on graphite are stressed. For radiation damage by plasma particles, the importance of understanding of the dynamic behaviors of the materials which are composite because of redeposition and hydrogen implantation. Some of the features of such composite materials under radiation are presented.

  19. A Computational Study of Hadron Radiation Damage to DNA Nucleobases

    DEFF Research Database (Denmark)

    Milhøj, Birgitte Olai

    Radiation damage of biomolecules is a signicant contributor to both the onset and also possible curing of cancer. Such damage is largely the result of free radicals that can be created by the interaction of high-energetic photons or ions with water within cells. Understanding the details of this ......Radiation damage of biomolecules is a signicant contributor to both the onset and also possible curing of cancer. Such damage is largely the result of free radicals that can be created by the interaction of high-energetic photons or ions with water within cells. Understanding the details...... of this interaction is therefore of vital importance to the medical community, but even after decades of thorough investigation the breakdown pattern of radiation damage has not yet been completely deciphered. This thesis represents a very comprehensive attempt at drawing conclusions on the initial step....... Considering this there is much novelty in the results drawn from the present study, as conclusions based also on the kinetics of the system imply that the hydrogen abstraction pathways are of equal importance for the possible reactions preceding the radiation damage. The purine nucleobases are found to favour...

  20. Probing Radiation Damage in Plutonium Alloys with Multiple Measurement Techniques

    Energy Technology Data Exchange (ETDEWEB)

    McCall, S K; Fluss, M J; Chung, B W

    2010-04-21

    A material subjected to radiation damage will usually experience changes in its physical properties. Measuring these changes in the physical properties provides a basis to study radiation damage in a material which is important for a variety of real world applications from reactor materials to semiconducting devices. When investigating radiation damage, the relative sensitivity of any given property can vary considerably based on the concentration and type of damage present as well as external parameters such as the temperature and starting material composition. By measuring multiple physical properties, these differing sensitivities can be leveraged to provide greater insight into the different aspects of radiation damage accumulation, thereby providing a broader understanding of the mechanisms involved. In this report, self-damage from {alpha}-particle decay in Pu is investigated by measuring two different properties: magnetic susceptibility and resistivity. The results suggest that while the first annealing stage obeys second order chemical kinetics, the primary mechanism is not the recombination of vacancy-interstitial close pairs.

  1. Typical Cell Signaling Response to Ionizing Radiation:DNA Damage and Extranuclear Damage

    Institute of Scientific and Technical Information of China (English)

    Hui Yu

    2012-01-01

    To treat many types of cancer,ionizing radiation (IR) is primarily used as external-beam radiotherapy,brachytherapy,and targeted radionuclide therapy.Exposure of tumor cells to IR can induce DNA damage as well as generation of reactiveoxygen species (ROS) and reactive nitrogen species (RNS) which can cause non-DNA lesions or extracellular damage like lipid perioxidation.The initial radiation-induced cell responses to DNA damage and ROS like the proteolytic processing,as well as synthesis and releasing ligands (such as growth factors,cytokines,and hormone) can cause the delayed secondary responses in irradiated and unirradiated bystander cells through paracrine and autocrine pathways.

  2. Animal Models of Ionizing Radiation Damage

    Science.gov (United States)

    1992-01-01

    Haggbloom, and R.A. Gazzara, Effects of Hippocampal X-irradiation-Produced Granule-Cell Agenesis on Instrumental Runway Performance in Rats, Physiol...Bowden, and J.P. Wyatt, A Pathway To Pulmonary Fibrosis: An Ultrastructural Study Of Mouse and Rat Following Radiation to the Whole Body and Hemithorax...532-536, 1956. 27. Brooks, P.M., E.O. Richey, and J.E. Pickering, Prompt Pulmonary Ventilation and Oxygen Consumption Changes in Rhesus Monkeys

  3. Heat induced damage detection in composite materials by terahertz radiation

    Science.gov (United States)

    Radzieński, Maciej; Mieloszyk, Magdalena; Rahani, Ehsan Kabiri; Kundu, Tribikram; Ostachowicz, Wiesław

    2015-03-01

    In recent years electromagnetic Terahertz (THz) radiation or T-ray has been increasingly used for nondestructive evaluation of various materials such as polymer composites and porous foam tiles in which ultrasonic waves cannot penetrate but T-ray can. Most of these investigations have been limited to mechanical damage detection like inclusions, cracks, delaminations etc. So far only a few investigations have been reported on heat induced damage detection. Unlike mechanical damage the heat induced damage does not have a clear interface between the damaged part and the surrounding intact material from which electromagnetic waves can be reflected back. Difficulties associated with the heat induced damage detection in composite materials using T-ray are discussed in detail in this paper. T-ray measurements are compared for different levels of heat exposure of composite specimens.

  4. Influence of radiation damage on BGO scintillation properties

    Energy Technology Data Exchange (ETDEWEB)

    Georgii, R.; Meissl, R.; Lichti, G.G.; Schoenfelder, V. [Max-Planck-Institut fuer Extraterrestrische Physik, Garching (Germany); Hajdas, W. [Paul-Scherrer Institut, CH-5232 Villigen (Switzerland); Henschel, H. [Fraunhofer-Institut fuer Naturwissenschaftlich-Technische Trendanalyse, D-53879 Euskirchen (Germany); Graef, H.-D.; Neumann-Cosel, P. von; Richter, A. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany)

    1998-08-11

    Aboard INTEGRAL, the next medium-size {gamma}-ray mission of the European Space Agency (ESA), a high-resolution Ge-spectrometer array with a BGO anticoincidence shield and imaging capability will be flown. The influence of the radiation damage on the photoelectron yield of the BGO scintillators due to the radiation environment in the orbit, i.e. {gamma}-rays, electrons and protons from the radiation, belts and the cosmic diffuse radiation, was investigated. Irradiation tests with doses equivalent to the orbit conditions were performed and the photoelectron yields of different BGO crystals were measured. It was found that for equal doses the reduction of the photoelectron yield varies strongly for the crystals of different manufacturers. Furthermore, electromagnetic radiation affects the photoelectron yield much stronger than particle radiation. A possible explanation is given by interpreting the effect due to {gamma}-rays primarily as damage of the electronic structure of the BGO, whereas the particle radiation damages mainly the crystal structure. (orig.) 19 refs.

  5. Damage Pattern as a Function of Various Types of Radiation

    Directory of Open Access Journals (Sweden)

    R.G. Ahmed

    2006-01-01

    Full Text Available The number of reports on the effects of various types of radiation is gradually increasing because of weakening of the immune system. Radiation can penetrate into living cells and result in the transfer of radiation energy to the biological material. The absorbed energy can increase the reactive oxygen species and break chemical bonds and cause ionization of different biologically essential macromolecules, such as DNA membrane lipids and proteins. Damage to the cellular membrane release the hydrolytic enzymes responsible for various catabolic processes in the tissues and leads to cell death. An understanding of the pattern in critical cellular structures such as DNA is an important prerequisite for a mechanistic assessment of primary radiation injury. The DNA damage induced by radiation such as base alterations, cross linking, strands breaker chromosomal aberration which may in turn lead to mutations. In order to further explore the harmful effects of radiation. I have produced a variety of effects of radiation on the apoptosis and necrosis. Indeed, the present review has shown that the increase in the oxidative stress (increased endogenous production of the free radicals due to radiation may be a reason for such a damage of the cell membrane, and may lead to harming the cellular elements (such as DNA. Here, one can hypothesize that, the cells with increased sensitivity to oxidative stress may be more susceptible to damage by radiation compared to normal cells. The ultimate biological consequences of this effect are subsequently processed by these cells. Much work remains to be done to firmly establish this concept.

  6. High-energy radiation damage in zirconia: modeling results

    Energy Technology Data Exchange (ETDEWEB)

    Zarkadoula, Eva; Devanathan, Ram; Weber, William J.; Seaton, Michael; Todorov, Ilian; Nordlund, Kai; Dove, Martin T.; Trachenko, Kostya

    2014-02-28

    Zirconia has been viewed as a material of exceptional resistance to amorphization by radiation damage, and was consequently proposed as a candidate to immobilize nuclear waste and serve as a 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 the 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 disjoint 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.

  7. High-energy radiation damage in zirconia: modeling results

    Energy Technology Data Exchange (ETDEWEB)

    Zarkadoula, Evangelia [Queen Mary, University of London; Devanathan, Ram [Pacific Northwest National Laboratory (PNNL); Weber, William J [ORNL; Seaton, M [Daresbury Laboratory, UK; Todorov, I T [Daresbury Laboratory, UK; Nordlund, Kai [University of Helsinki; Dove, Martin T [Queen Mary, University of London; Trachenko, Kostya [Queen Mary, University of London

    2014-01-01

    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 nd 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Zarkadoula, E., E-mail: zarkadoulae@ornl.gov [School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); SEPnet, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Devanathan, R. [Nuclear Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Weber, W. J. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States); Seaton, M. A.; Todorov, I. T. [STFC Daresbury Laboratory, Scientific Computing Department, Keckwick Lane, Daresbury, Warrington, Cheshire WA4 4AD (United Kingdom); Nordlund, K. [University of Helsinki, P.O. Box 43, FIN-00014 Helsinki (Finland); Dove, M. T. [School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Trachenko, K. [School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); SEPnet, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom)

    2014-02-28

    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.

  9. Kinetic model for the pathogenesis of radiation lung damage

    Energy Technology Data Exchange (ETDEWEB)

    Collis, C.H. (Institute of Cancer Research, Sutton (UK). Surrey Branch)

    1982-09-01

    The development of radiation-induced lung damage can be explained by a kinetic model, based on the assumption that this damage becomes manifest only when a critical proportion (K) of essential cells have ceased to function, and that the rate of loss of these cells following irradiation is linear and dose-dependent. The kinetic model relates the surviving fraction to the time to manifestation of radiation-induced lung damage and to constants, K and the cell cycle time, T. Predictions made from the model about the nature of the response to irradiation are, for the most part, fulfilled. The model can also be used to interpret the response to combined treatment with irradiation and cytotoxic drugs, including the much earlier manifestation of lung damage sometimes seen with such treatment.

  10. Low cost CCD camera protection against neutron radiation damage.

    Science.gov (United States)

    Kok, J G M

    2005-01-01

    At a radiotherapy department cancer patients are treated with high energy electron and photon beams. These beams are produced by a linear accelerator. A closed circuit television system is used to monitor patients during treatment. Although CCD cameras are rather resistant to stray radiation, they are damaged by the low flux of neutrons which are produced by the linac as a side effect. PVC can be used to reduce damage to CCD cameras induced by neutron radiation. A box with 6 cm thick walls will extend the life of the camera at least by a factor of two. A PVC neutron shield is inexpensive. PVC is easy to obtain and the box is simple to construct. A similar box made out of PE will not reduce neutron damage to a CCD camera. Although PE is a good medium to moderate faster neutrons, thereby reducing some of the bulk defects, it will not capture thermal neutrons which induce surface damage.

  11. Effects of sunlight exposure on grapevine powdery mildew development.

    Science.gov (United States)

    Austin, Craig N; Wilcox, Wayne F

    2012-09-01

    Natural and artificially induced shade increased grapevine powdery mildew (Erysiphe necator) severity in the vineyard, with foliar disease severity 49 to 75% higher relative to leaves in full sun, depending on the level of natural shading experienced and the individual experiment. Cluster disease severities increased by 20 to 40% relative to those on check vines when ultraviolet (UV) radiation was filtered from sunlight reaching vines in artificial shading experiments. Surface temperatures of leaves in full sunlight averaged 5 to 8°C higher than those in natural shade, and in one experiment, filtering 80% of all wavelengths of solar radiation, including longer wavelengths responsible for heating irradiated tissues, increased disease more than filtering UV alone. In controlled environment experiments, UV-B radiation reduced germination of E. necator conidia and inhibited both colony establishment (hyphal formation and elongation) and maturity (latent period). Inhibitory effects of UV-B radiation were significantly greater at 30°C than at 20 or 25°C. Thus, sunlight appears to inhibit powdery mildew development through at least two mechanisms, i.e., (i) UV radiation's damaging effects on exposed conidia and thalli of the pathogen; and (ii) elevating temperatures of irradiated tissues to a level supraoptimal or inhibitory for pathogen development. Furthermore, these effects are synergistic at temperatures near the upper threshold for disease development.

  12. Radiation damage studies of silicon microstrip sensors

    CERN Document Server

    Nakayama, T; Hara, K; Shimojima, M; Ikegami, Y; Iwata, Y; Johansen, L G; Kobayashi, H; Kohriki, T; Kondo, T; Nakano, I; Ohsugi, T; Riedler, P; Roe, S; Stapnes, Steinar; Stugu, B; Takashima, R; Tanizaki, K; Terada, S; Unno, Y; Yamamoto, K; Yamamura, K

    2000-01-01

    Various types of large area silicon microstrip detectors were fabricated for the development of radiation-tolerant detectors that will operate in the LHC ATLAS SCT. The detectors were irradiated with 12-GeV protons at KEK to fluences of 1.7*10/sup 14/ and 4.2*10/sup 14 / protons/cm/sup 2/. Irradiated samples included n-on-n detectors with 4 k Omega cm bulk resistivity and p-on-n detectors with 1 k Omega cm and 4 k Omega cm bulk resistivities. Four patterns of p-stop structures are configured in the n-on-n detectors. Although Hamamatsu fabricated most of the detectors, p-on-n detectors by SINTEF are also included, as well as those fabricated in a modified process by Hamamatsu. The detector performances after irradiation that are compared are the probability of creation of faulty coupling capacitors, C-V characteristics, charge curves, and total leakage current. The p-on-n are similar to the n-on-n detectors in these performances, and will remain operational in the ATLAS radiation environment. (12 refs).

  13. Proton-radiation damage in Gunn oscillators

    Science.gov (United States)

    Johnson, J. W.; Fales, C. L., Jr.

    1973-01-01

    The irradiation effects of 22 MeV protons on the electrical characteristics of GaAs continuous-wave Gunn oscillators was studied. The radio frequency power output was reduced by 3 decibels at proton fluences in the neighborhood of 1.5 x 10 to the 12th power protons/sq cm. Conductance measurements indicate that the carrier removal rate at high electric fields remained roughly 40 percent less than at low fields. Diode efficiencies of two device groups were found to be monotonically descreasing functions of fluence. Frequency modulation noise was generally unaffected by radiation, but the magnitude of the noise in the noise power spectrum increased significantly. These effects are partially accounted for, in a qualitative fashion, by a model of electron traps having field-dependent net-carrier capture rates and various response times.

  14. Simulating radiation damage in {delta}-plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, M. [Department of Mathematical Sciences, Loughborough University, Loughborough, LE11 3TU (United Kingdom)], E-mail: m.robinson@lboro.ac.uk; Kenny, S.D.; Smith, R. [Department of Mathematical Sciences, Loughborough University, Loughborough, LE11 3TU (United Kingdom); Storr, M.T.; McGee, E. [Atomic Weapons Establishment, Aldermaston, Reading, RG7 4PR (United Kingdom)

    2009-09-15

    Radiation events in {delta}-Pu (fcc) have been simulated in an attempt to understand the fundamental mechanisms that contribute to the Pu ageing process. The Pu interactions are modelled using a potential based on the modified embedded atom method (MEAM). The energetics of point defects have been investigated using static calculations together with molecular dynamics (MD) to simulate radiation events. All MD simulations were carried out with Pu initially in the face-centred-cubic (fcc) structure, although this is not the lowest energy configuration for the pure metal. The point defect study suggests that the mono-vacancy has the lowest formation energy (0.46 eV), with interstitial defects favouring the <100> - split orientation over occupation of the native fcc octahedral site. Displacement threshold energy calculations at room temperature give a minimum value of between 5 and 6 eV, increasing to 8-14 eV along the major crystallographic directions. Low energy collision cascades, initiated with energies in the range of 0.4-1 keV, show that the cascades form in a similar manner to other fcc metals with a vacancy rich zone at the cascade core, surrounded by isolated interstitial defects. Higher energy cascades show similar features but with occasional channelling of energetic atoms and sub-cascade branching which significantly reduces defect production. A common trait observed across all the cascades was the relatively slow annealing period, compared to cascades in other fcc metals, with simulations at energies above 5 keV requiring many 10's of picoseconds before the ballistic phase was completed.

  15. 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.

  16. Inducible HSP70 Protects Radiation-Induced Salivary Gland Damage

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hae-June; Lee, Yoon-Jin; Kwon, Hee-Choong; Lee, Su-Jae; Bae, Sang-Woo; Lee, Yun-Sil [Korea Institute of Radiological Medical Sciences, Seoul (Korea, Republic of); Kim, Sung-Ho [Chonnam National University, Gwangju (Korea, Republic of)

    2006-07-01

    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.

  17. Radiation damage in nonmetallic solids under dense electronic excitation

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Noriaki; Tanimura, Katsumi; Nakai, Yasuo (Dept. of Physics, Nagoya Univ. (Japan))

    1992-03-01

    Basic processes of radiation damage of insulators by dense electronic excitation are reviewed. First it is pointed out that electronic excitation of nonmetallic solids produces the self-trapped excitons and defect-related metastable states having relatively long lifetimes, and that the excitation of these metastable states, produces stable defects. The effects of irradiation with heavy ions, including track registration, are surveyed on the basis of the microscopic studies. It is pointed out also that the excitation of the metastable states plays a role in laser-induced damage at relatively low fluences, while the laser damage has been reported to be governed by heating of free electrons produced by multiphoton excitation. Difference in the contributions of the excitation of metastable defects to laser-induced damage of surfaces, or laser ablation, and laser-induced bulk damage is stressed. (orig.).

  18. Radiation Damage Studies of Silicon Photomultipliers

    CERN Document Server

    Bohn, P; Hazen, E.; Heering, A.; Rohlf, J.; Freeman, J.; Los, Sergey V.; 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...

  19. Radiation damage aspects of the Chernobyl accident

    Energy Technology Data Exchange (ETDEWEB)

    Parmentier, N.; Nenot, J.C. (CEA Centre d' Etudes Nucleaires de Fontenay-aux-Roses, 92 (France). Inst. de Protection et de Surete Nucleaire)

    1989-01-01

    During the night of 25 to 26 April 1986, the most severe nuclear accident occurred at the Chernobyl power stations. It resulted in the irradiation of 237 workers at dose levels justifying medical care. The most severe cases (115) were hospitalized in Moscow, with 20 patients with doses higher than 6 Gy. In most cases, the treatment was classical, based on transfusion of red cells and platelets, and heavy supportive therapy. For 19 patients with severe aplasia, transplantations of bone marrow (13) or foetal liver (6) were decided. Of these patients only one survived, which justifies the statement from U.S.S.R. physicians: after an accident the indications of grafting are limited and its risks may not justify its use. Most of the complications were related to radiation burns which involved 56 victims and resulted in fatal outcomes in at least 19 patients. The population was evacuated from a 30 km zone around the site; based on direct measurements and calculations, the collective dose was evaluated at 1.6 x 10{sup 4} man Sv, with an individual average lower than 250 mSv. The European part of U.S.S.R. with 75 million persons is supposed to have received a collective dose likely to increase the natural mortality by less than 0.1%. The numbers with cancer in the Northern Hemisphere might increase by 0.004% over the next 50 years.

  20. Radiation damage aspects of the chernobyl accident

    Science.gov (United States)

    Parmentier, N.; Nenot, J. C.

    During the night of 25 to 26 April 1986, the most severe nuclear accident occurred at the Chernobyl power station, about 150km north of Kiev, in the Ukraine. It resulted in the irradiation of 237 workers at dose levels justifying medical care. The most severe cases (115) were hospitalized in Moscow, with 20 patients with doses higher than 6 Gy. In most cases, the treatment was classical, based on transfusion of red cells and platelets, and heavy supportive therapy. For 19 patients with severe aplasia, transplantations of bone marrow (13) or foetal liver (6) were decided. Of these patients only one survived, which justifies the statement from U.S.S.R. physicians: after an accident the indications of grafting are limited and its risks may not justify its use. Most of the complications were related to radiation burns which involved 56 victims and resulted in fatal outcomes in at least 19 patients. The population was evacuated from a 30 km zone around the site; based on direct measurements and calculations, the collective dose was evaluated at 1.6 × 10 4 man Sv, with an individual average lower than 250 mSv. The European part of U.S.S.R. with 75 million persons is supposed to have received a collective dose likely to increase the natural mortality by less than 0.1%. The numbers with cancer in the Northern Hemisphere might increase by 0.004% over the next 50 years.

  1. 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...

  2. 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.

  3. 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

  4. Genomic damage in children accidentally exposed to ionizing radiation

    DEFF Research Database (Denmark)

    Fucic, A; Brunborg, G; Lasan, R

    2007-01-01

    doses of radiation; (b) effects on children from combined exposure to low doses of radiation and chemical agents from food, water and air; and (c) specific effects from exposure during early childhood (radioisotopes from water, radon in homes). Special consideration should also be given to a possible......, environmental radiation pollution and indoor accidental contamination reveals consistently increased chromosome aberration and micronuclei frequency in exposed than in referent children. Future research in this area should be focused on studies providing information on: (a) effects on children caused by low...... of children to environmental genotoxicants. Environmental research on children predominantly investigates the health effects of air pollution while effects from radiation exposure deserve more attention. The main sources of knowledge on genome damage of children exposed to radiation are studies performed...

  5. 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.

  6. Recent results of radiation damage studies in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Bates, S.J.; Munday, D.J.; Parker, M.A.; Anghinolfi, F.; Chilingarov, A.; Ciasnohova, A.; Glaser, M.; Heijne, E.; Jarron, P.; Lemeilleur, F.; Santiard, J.C.; Bonino, R.; Clark, A.G.; Kambara, H.; Goessling, C.; Lisowski, B.; Rolf, A.; Pilath, S.; Feick, H.; Fretwurst, E.; Lindstroem, G.; Schulz, T.; Bardos, R.A.; Gorfine, G.W.; Moorhead, G.F.; Taylor, G.N.; Tovey, S.N. (Cavendish Lab., Univ. of Cambridge (United Kingdom) CERN, Geneva (Switzerland) DPNC, Univ. de Geneve (Switzerland) Inst. fuer Physik, Univ. Dortmund (Germany) 1. Inst. fuer Experimentalphysik, Univ. Hamburg (Germany) School of Physics, Univ. of Melbourne (Australia))

    1994-04-21

    The RD2 Collaboration is making preliminary studies on a silicon tracking detector for use at the LHC. It is a priority that this detector should withstand the high level of radiation to be expected for LHC operation. Therefore systematic studies on the change of the detector performance due to radiation damage have been made, or are in progress. Well established results on neutron related damage at room temperature have been extended to lower temperatures, as foreseen for operation at LHC. For comparison proton damage studies have also been started. The detector properties under investigation include the reverse current, the depletion voltage and the charge collection efficiency. With a compressed 10 year LHC operational scenario we have successfully checked the ability of silicon detectors to survive the period influences of high fluence irradiation and subsequent annealing. (orig.)

  7. 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.

  8. GUI to Facilitate Research on Biological Damage from Radiation

    Science.gov (United States)

    Cucinotta, Frances A.; Ponomarev, Artem Lvovich

    2010-01-01

    A graphical-user-interface (GUI) computer program has been developed to facilitate research on the damage caused by highly energetic particles and photons impinging on living organisms. The program brings together, into one computational workspace, computer codes that have been developed over the years, plus codes that will be developed during the foreseeable future, to address diverse aspects of radiation damage. These include codes that implement radiation-track models, codes for biophysical models of breakage of deoxyribonucleic acid (DNA) by radiation, pattern-recognition programs for extracting quantitative information from biological assays, and image-processing programs that aid visualization of DNA breaks. The radiation-track models are based on transport models of interactions of radiation with matter and solution of the Boltzmann transport equation by use of both theoretical and numerical models. The biophysical models of breakage of DNA by radiation include biopolymer coarse-grained and atomistic models of DNA, stochastic- process models of deposition of energy, and Markov-based probabilistic models of placement of double-strand breaks in DNA. The program is designed for use in the NT, 95, 98, 2000, ME, and XP variants of the Windows operating system.

  9. Thermal annealing of natural, radiation-damaged pyrochlore

    Energy Technology Data Exchange (ETDEWEB)

    Zietlow, Peter; Mihailova, Boriana [Hamburg Univ. (Germany). Dept. of Earth Sciences; Beirau, Tobias [Hamburg Univ. (Germany). Dept. of Earth Sciences; Stanford Univ., CA (United States). Dept. of Geological Sciences; and others

    2017-03-01

    Radiation damage in minerals is caused by the α-decay of incorporated radionuclides, such as U and Th and their decay products. The effect of thermal annealing (400-1000 K) on radiation-damaged pyrochlores has been investigated by Raman scattering, X-ray powder diffraction (XRD), and combined differential scanning calorimetry/thermogravimetry (DSC/TG). The analysis of three natural radiation-damaged pyrochlore samples from Miass/Russia [6.4 wt% Th, 23.1.10{sup 18} α-decay events per gram (dpg)], Panda Hill/Tanzania (1.6 wt% Th, 1.6.10{sup 18} dpg), and Blue River/Canada (10.5 wt% U, 115.4.10{sup 18} dpg), are compared with a crystalline reference pyrochlore from Schelingen (Germany). The type of structural recovery depends on the initial degree of radiation damage (Panda Hill 28%, Blue River 85% and Miass 100% according to XRD), as the recrystallization temperature increases with increasing degree of amorphization. Raman spectra indicate reordering on the local scale during annealing-induced recrystallization. As Raman modes around 800 cm{sup -1} are sensitive to radiation damage (M. T. Vandenborre, E. Husson, Comparison of the force field in various pyrochlore families. I. The A{sub 2}B{sub 2}O{sub 7} oxides. J. Solid State Chem. 1983, 50, 362, S. Moll, G. Sattonnay, L. Thome, J. Jagielski, C. Decorse, P. Simon, I. Monnet, W. J. Weber, Irradiation damage in Gd{sub 2}Ti{sub 2}O{sub 7} single crystals: Ballistic versus ionization processes. Phys. Rev. 2011, 84, 64115.), the degree of local order was deduced from the ratio of the integrated intensities of the sum of the Raman bands between 605 and 680 cm{sup -1} divided by the sum of the integrated intensities of the bands between 810 and 860 cm{sup -1}. The most radiation damaged pyrochlore (Miass) shows an abrupt recovery of both, its short- (Raman) and long-range order (X-ray) between 800 and 850 K, while the weakly damaged pyrochlore (Panda Hill) begins to recover at considerably lower temperatures (near 500 K

  10. Laser annealing heals radiation damage in avalanche photodiodes

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jin Gyu [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Electrical and Computer Engineering, Waterloo, ON (Canada); Anisimova, Elena; Higgins, Brendon L.; Bourgoin, Jean-Philippe [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada); Jennewein, Thomas [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada); Canadian Institute for Advanced Research, Quantum Information Science Program, Toronto, ON (Canada); Makarov, Vadim [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Electrical and Computer Engineering, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada)

    2017-12-15

    Avalanche photodiodes (APDs) are a practical option for space-based quantum communications requiring single-photon detection. However, radiation damage to APDs significantly increases their dark count rates and thus reduces their useful lifetimes in orbit. We show that high-power laser annealing of irradiated APDs of three different models (Excelitas C30902SH, Excelitas SLiK, and Laser Components SAP500S2) heals the radiation damage and several APDs are restored to typical pre-radiation dark count rates. Of nine samples we test, six APDs were thermally annealed in a previous experiment as another solution to mitigate the radiation damage. Laser annealing reduces the dark count rates further in all samples with the maximum dark count rate reduction factor varying between 5.3 and 758 when operating at -80 C. This indicates that laser annealing is a more effective method than thermal annealing. The illumination power to reach these reduction factors ranges from 0.8 to 1.6 W. Other photon detection characteristics, such as photon detection efficiency, timing jitter, and afterpulsing probability, fluctuate but the overall performance of quantum communications should be largely unaffected by these variations. These results herald a promising method to extend the lifetime of a quantum satellite equipped with APDs. (orig.)

  11. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, J. [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra (Australia); Gaugliardo, P. [Centre for Antimatter-Matter Studies, School of Physics, University of Western Australia (Australia); Farnan, I.; Zhang, M. [Department of Earth Sciences, University of Cambridge (United Kingdom); Vance, E.R.; Davis, J.; Karatchevtseva, I.; Knott, R.B. [Australian Nuclear Science and Technology Organisation (Australia); Mudie, S. [The Australian Synchrotron, Victoria (Australia); Buckman, S.J. [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra (Australia); Institute for Mathematical Sciences, University of Malaya, Kuala Lumpur (Malaysia); Sullivan, J.P., E-mail: james.sullivan@anu.edu.au [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra (Australia)

    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 ∼10{sup 19} 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. - Highlights: • Study of a range of naturally occurring zircons damaged by alpha radiation. • Characterised using a range of techniques, including PALS spectroscopy. • Effects on hydrous material appear important, rather than direct radiation damage. • Annealing is shown to remove the observed voids.

  13. 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.

  14. Non-Thermal Electromagnetic Radiation Damage to Lens Epithelium

    OpenAIRE

    Bormusov, Elvira; P.Andley, Usha; Sharon, Naomi; Schächter, Levi; Lahav, Assaf; Dovrat, Ahuva

    2008-01-01

    High frequency microwave electromagnetic radiation from mobile phones and other modern devices has the potential to damage eye tissues, but its effect on the lens epithelium is unknown at present. The objective of this study was to investigate the non-thermal effects of high frequency microwave electromagnetic radiation (1.1GHz, 2.22 mW) on the eye lens epithelium in situ. Bovine lenses were incubated in organ culture at 35°C for 10-15 days. A novel computer-controlled microwave source was us...

  15. Radiation Damage Study on the Electrical Properties of Si Diodes

    Science.gov (United States)

    Pascoalino, Kelly C. S.; Gonçalves, Josemary A. C.; Tobias, Carmen C. B.

    2011-08-01

    The aim of this work was to study the radiation damage effects on the electrical properties of Float Zone (FZ) and Magnetic Czochralski (MCz) diodes. The effects were evaluated by measuring the reverse current and capacitance of these devices as a function of the reverse voltage. The irradiation was performed in the Radiation Technology Center (CTR) at IPEN-CNEN/SP using a 60Co irradiator (Gammacell 220-Nordion) with a dose rate of about 2 kGy/h. Samples were irradiated at room temperature in five steps up to an accumulated dose of 603 kGy.

  16. 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.

  17. Non-thermal electromagnetic radiation damage to lens epithelium.

    Science.gov (United States)

    Bormusov, Elvira; P Andley, Usha; Sharon, Naomi; Schächter, Levi; Lahav, Assaf; Dovrat, Ahuva

    2008-05-21

    High frequency microwave electromagnetic radiation from mobile phones and other modern devices has the potential to damage eye tissues, but its effect on the lens epithelium is unknown at present. The objective of this study was to investigate the non-thermal effects of high frequency microwave electromagnetic radiation (1.1GHz, 2.22 mW) on the eye lens epithelium in situ. Bovine lenses were incubated in organ culture at 35°C for 10-15 days. A novel computer-controlled microwave source was used to investigate the effects of microwave radiation on the lenses. 58 lenses were used in this study. The lenses were divided into four groups: (1) Control lenses incubated in organ culture for 10 to15 days. (2) Electromagnetic radiation exposure group treated with 1.1 GHz, 2.22 mW microwave radiation for 90 cycles of 50 minutes irradiation followed by 10 minutes pause and cultured up to 10 days. (3) Electromagnetic radiation exposure group treated as group 2 with 192 cycles of radiation and cultured for 15 days. (4) Lenses exposed to 39.5°C for 2 hours 3 times with 24 hours interval after each treatment beginning on the second day of the culture and cultured for 11 days. During the culture period, lens optical quality was followed daily by a computer-operated scanning laser beam. At the end of the culture period, control and treated lenses were analyzed morphologically and by assessment of the lens epithelial ATPase activity. Exposure to 1.1 GHz, 2.22 mW microwaves caused a reversible decrease in lens optical quality accompanied by irreversible morphological and biochemical damage to the lens epithelial cell layer. The effect of the electromagnetic radiation on the lens epithelium was remarkably different from those of conductive heat. The results of this investigation showed that electromagnetic fields from microwave radiation have a negative impact on the eye lens. The lens damage by electromagnetic fields was distinctly different from that caused by conductive heat.

  18. 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.

  19. Site-selective radiation damage of collapsed carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Crespi, V.H. [Department of Physics, 104 Davey Lab, The Pennsylvania State University, University Park, Pennsylvania 16802-6300 (United States); Chopra, N.G.; Cohen, M.L.; Zettl, A. [Department of Physics, University of California at Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Radmilovic, V. [Department of Physical Metallurgy, University of Belgrade Karnegijeva 4, P.O. Box 494, Belgrade, 11001 (Yugoslavia)

    1998-10-01

    Carbon nanotubes can flatten into collapsed tubes with bulbs along either edge. The strong anisotropy in the graphitic radiation damage threshold both explains the rapid destruction of face-on flattened nanotubes and can be exploited to selectively modify the structure of edge-on flattened nanotubes, thereby creating one-dimensional sp{sup 2} carbon with noncontinuous transverse boundary conditions. {copyright} {ital 1998 American Institute of Physics.}

  20. Low dose radiation damage effects in silicon strip detectors

    Science.gov (United States)

    Wiącek, P.; Dąbrowski, W.

    2016-11-01

    The radiation damage effects in silicon segmented detectors caused by X-rays have become recently an important research topic driven mainly by development of new detectors for applications at the European X-ray Free Electron Laser (E-XFEL). However, radiation damage in silicon strip is observed not only after extreme doses up to 1 GGy expected at E-XFEL, but also at doses in the range of tens of Gy, to which the detectors in laboratory instruments like X-ray diffractometers or X-ray spectrometers can be exposed. In this paper we report on investigation of radiation damage effects in a custom developed silicon strip detector used in laboratory diffractometers equipped with X-ray tubes. Our results show that significant degradation of detector performance occurs at low doses, well below 200 Gy, which can be reached during normal operation of laboratory instruments. Degradation of the detector energy resolution can be explained by increasing leakage current and increasing interstrip capacitance of the sensor. Another observed effect caused by accumulation of charge trapped in the surface oxide layer is change of charge division between adjacent strips. In addition, we have observed unexpected anomalies in the annealing process.

  1. Sunlight-induced DNA damage in marine micro-organisms collected along a latitudinal gradient from 70 degrees N to 68 degrees S.

    Science.gov (United States)

    Meador, Jarah A; Baldwin, Amy J; Catala, Phillipe; Jeffrey, Wade H; Joux, Fabien; Moss, Joseph A; Dean Pakulski, J; Stevens, Richard; Mitchell, David L

    2009-01-01

    We examined ultraviolet radiation (UVR)-induced DNA damage in marine micro-organisms collected from surface seawater along a latitudinal transect in the Central Pacific Ocean from 70 degrees N to 68 degrees S. Samples were collected predawn and incubated under ambient UVR in transparent incubators at in situ temperatures until late afternoon at which time they were filtered into primarily bacterioplankton and eukaryotic fractions. Cyclobutane pyrimidine dimers (CPDs) and (6-4) photoproducts [(6-4)PDs] were quantified in DNA extracts using radioimmunoassays. UVB was lowest in the polar regions and highest near the equator and correlations between UVB and DNA damage were observed. The eukaryotic fraction showed significant CPDs across the entire transect; (6-4)PDs were detected only in the tropics. The bacterial fraction showed no accumulation of (6-4)PDs at any latitude, although residual (6-4)PDs were observed. Bacterial cell volumes were greatest in the sub-Arctic and northern temperate latitudes and lower in the tropics and southern hemisphere, a unique observation that parallels Bergmann's rule. A strong negative correlation was observed between cell volume and CPDs. The environmental impact of solar UVR on marine micro-organisms in the open ocean is complex and our results suggest that several factors such as DNA repair, cell size, temperature, salinity, nutrients and species composition are important in determining relative sensitivity.

  2. Radiation damage measurements on CZT drift strip detectors

    Energy Technology Data Exchange (ETDEWEB)

    Kuvvetli, I. E-mail: irfan@dsri.dk; Budtz-Joergensen, C. E-mail: carl@dsri.dk; Korsbech, U.; Jensen, H.J

    2003-10-11

    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 from 2x10{sup 8} to 60x10{sup 8} p{sup +}/cm{sup 2}. Even for the highest fluences, which had a dramatic effect on the spectroscopic performance, we were able to recover the detectors after an appropriate annealing procedure. The radiation damage was studied as a function of depth inside the detector material. A numerical model that emulates the physical processes of the charge transport in the CZT detector was used to derive the charge trapping parameter, {mu}{tau}{sub e} (the product of charge mobility and trapping time) as a function of fluence. The analysis showed that the electron trapping increased proportionately with the proton dose. The radiation contribution to the electron trapping was found to obey the following relation: ({mu}{tau}{sub e}{sup -1}){sub rad}=(2.5{+-}0.2)x10{sup -7}xPHI (V/cm){sup 2} with the proton fluence, PHI in p{sup +}/cm{sup 2}. The trapping depth dependence, however, did not agree well with the damage profile calculated using the standard Monte Carlo simulations, TRIM , for the proton-induced radiation effects. The present results suggest that proton-induced nuclear reactions contribute significantly to the radiation damage. Further work will elaborate on these effects.

  3. Radiation damage measurements on CZT drift strip detectors

    Science.gov (United States)

    Kuvvetli, I.; Budtz-Jørgensen, C.; Korsbech, U.; Jensen, H. J.

    2003-10-01

    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 from 2×10 8 to 60×10 8 p +/cm 2. Even for the highest fluences, which had a dramatic effect on the spectroscopic performance, we were able to recover the detectors after an appropriate annealing procedure. The radiation damage was studied as a function of depth inside the detector material. A numerical model that emulates the physical processes of the charge transport in the CZT detector was used to derive the charge trapping parameter, μτe (the product of charge mobility and trapping time) as a function of fluence. The analysis showed that the electron trapping increased proportionately with the proton dose. The radiation contribution to the electron trapping was found to obey the following relation: (μτ e- 1) rad=(2.5±0.2)×10 -7×Φ ( V/cm)2 with the proton fluence, Φ in p +/cm 2. The trapping depth dependence, however, did not agree well with the damage profile calculated using the standard Monte Carlo simulations, TRIM [1], for the proton-induced radiation effects. The present results suggest that proton-induced nuclear reactions contribute significantly to the radiation damage. Further work will elaborate on these effects.

  4. Tailoring radiation damage in ZnO by surface modification

    Science.gov (United States)

    Myers, M. T.; Charnvanichborikarn, S.; Myers, M. A.; Lee, J. H.; Wang, H.; Biener, M. M.; Shao, L.; Kucheyev, S. O.

    2013-07-01

    Heavy-ion irradiation of (0 0 0 1) ZnO crystals results in unusual damage buildup, including an additional (intermediate) peak in damage-depth profiles measured by ion channeling, the formation of near-surface nanocavities, and stoichiometric imbalance. All these effects are thought to be associated with the influence of the sample surface on dynamic annealing processes. Here, by using ion channeling and transmission electron microscopy, we find that placing an ~7 nm thick AlO(OH) layer on the (0 0 0 1) ZnO surface results in (i) suppression of cavity formation, (ii) a reduced intermediate defect peak intensity, and (iii) a decreased level of disorder extending up to ~100 nm from the ZnO surface for room-temperature bombardment with 500 keV Xe ions. Our results demonstrate the potential to control radiation damage in ZnO by surface manipulation.

  5. Heat Induced Damage Detection by Terahertz (THz) Radiation

    Science.gov (United States)

    Rahani, Ehsan Kabiri; Kundu, Tribikram; Wu, Ziran; Xin, Hao

    2011-06-01

    Terahertz (THz) and sub-terahertz imaging and spectroscopy are becoming increasingly popular nondestructive evaluation techniques for damage detection and characterization of materials. THz radiation is being used for inspecting ceramic foam tiles used in TPS (Thermal Protection System), thick polymer composites and polymer tiles that are not good conductors of ultrasonic waves. Capability of THz electromagnetic waves in detecting heat induced damage in porous materials is investigated in this paper. Porous pumice stone blocks are subjected to long time heat exposures to produce heat induced damage in the block. The dielectric properties extracted from THz TDS (Time Domain Spectroscopy) measurements are compared for different levels of heat exposure. Experimental results show noticeable and consistent change in dielectric properties with increasing levels of heat exposure, well before its melting point.

  6. HSP25 Protects Radiation-Induced Salivary Gland Damage

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hae June; Lee, Yoon Jin; Kwon, Hee Choong; Lee, Su Jae; Bae, Sang Woo; Lee, Yun Sil [Korea Institute of Radiological Medical Sciences, Seoul (Korea, Republic of); Kim, Sung Ho [Chonnam National Univ., Gwangju (Korea, Republic of)

    2005-07-01

    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.

  7. Self-radiation damage in plutonium and uranium mixed dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Masato; Endo, Hideo [Japan Nuclear Cycle Development Inst., Tokai Works, Tokai, Ibaraki (Japan); Sugata, Hiromasa [Inspection Development Company Ltd., Tokai, Ibaraki (Japan)

    2002-12-01

    In plutonium compounds, self-radiation induces expansion of the lattice parameter as a function of time. The expansion of the lattice parameter and thermal recovery of radiation damage in plutonium and uranium mixed dioxide (MOX) were studied in this paper. The MOX powder had been kept in an ambient atmosphere for about two years. The lattice parameter of the powder saturated after an increase of about 0.23%. The change in the lattice parameter was formulated as a function of the self-radiation amount. Three thermal recovery stages of radiation damage were observed in temperature ranges below 400degC, 400-800degC and above 800degC. The recovery rate of the three stages in total lattice expansion was about 25%, 55% and 20%, respectively, and activation energy in each recovery was estimated to be 0.14 eV, 0.54 eV and 1.1 eV. (author)

  8. Radiation track, DNA damage and response—a review

    Science.gov (United States)

    Nikjoo, H.; Emfietzoglou, D.; Liamsuwan, T.; Taleei, R.; Liljequist, D.; Uehara, S.

    2016-11-01

    The purpose of this paper has been to review the current status and progress of the field of radiation biophysics, and draw attention to the fact that physics, in general, and radiation physics in particular, with the aid of mathematical modeling, can help elucidate biological mechanisms and cancer therapies. We hypothesize that concepts of condensed-matter physics along with the new genomic knowledge and technologies and mechanistic mathematical modeling in conjunction with advances in experimental DNA (Deoxyrinonucleic acid molecule) repair and cell signaling have now provided us with unprecedented opportunities in radiation biophysics to address problems in targeted cancer therapy, and genetic risk estimation in humans. Obviously, one is not dealing with ‘low-hanging fruit’, but it will be a major scientific achievement if it becomes possible to state, in another decade or so, that we can link mechanistically the stages between the initial radiation-induced DNA damage; in particular, at doses of radiation less than 2 Gy and with structural changes in genomic DNA as a precursor to cell inactivation and/or mutations leading to genetic diseases. The paper presents recent development in the physics of radiation track structure contained in the computer code system KURBUC, in particular for low-energy electrons in the condensed phase of water for which we provide a comprehensive discussion of the dielectric response function approach. The state-of-the-art in the simulation of proton and carbon ion tracks in the Bragg peak region is also presented. The paper presents a critical discussion of the models used for elastic scattering, and the validity of the trajectory approach in low-electron transport. Brief discussions of mechanistic and quantitative aspects of microdosimetry, DNA damage and DNA repair are also included as developed by the authors’ work.

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

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Yoshiyuki [Osaka Dental Univ., Hirakata (Japan)

    2000-03-01

    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)

  10. Chromatin modifications and the DNA damage response to ionizing radiation

    Science.gov (United States)

    Kumar, Rakesh; Horikoshi, Nobuo; Singh, Mayank; Gupta, Arun; Misra, Hari S.; Albuquerque, Kevin; Hunt, Clayton R.; Pandita, Tej K.

    2013-01-01

    In order to survive, cells have evolved highly effective repair mechanisms to deal with the potentially lethal DNA damage produced by exposure to endogenous as well as exogenous agents. Ionizing radiation exposure induces highly lethal DNA damage, especially DNA double-strand breaks (DSBs), that is sensed by the cellular machinery and then subsequently repaired by either of two different DSB repair mechanisms: (1) non-homologous end joining, which re-ligates the broken ends of the DNA and (2) homologous recombination, that employs an undamaged identical DNA sequence as a template, to maintain the fidelity of DNA repair. Repair of DSBs must occur within the natural context of the cellular DNA which, along with specific proteins, is organized to form chromatin, the overall structure of which can impede DNA damage site access by repair proteins. The chromatin complex is a dynamic structure and is known to change as required for ongoing cellular processes such as gene transcription or DNA replication. Similarly, during the process of DNA damage sensing and repair, chromatin needs to undergo several changes in order to facilitate accessibility of the repair machinery. Cells utilize several factors to modify the chromatin in order to locally open up the structure to reveal the underlying DNA sequence but post-translational modification of the histone components is one of the primary mechanisms. In this review, we will summarize chromatin modifications by the respective chromatin modifying factors that occur during the DNA damage response. PMID:23346550

  11. Defense mechanisms against radiation induced teratogenic damage in mice

    Energy Technology Data Exchange (ETDEWEB)

    Kato, F.; Ootsuyama, A.; Nomoto, S.; Norimura, T. [Univ. of Occupational and Environmental Health, Kitakyushu, (Japan)

    2002-07-01

    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 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...... from 2 x 10(8) to 60 x 10(8) p(+)/cm(2). Even for the highest fluences, which had a dramatic effect on the spectroscopic performance, we were able to recover the detectors after an appropriate annealing procedure. The radiation damage was studied as a function of depth inside the detector material...... with the proton dose. The radiation contribution to the electron trapping was found to obey the following relation: (mutau(e)(-1))(rad) = (2.5+/-0.2) x 10(-7) x Phi (V/cm)(2) with the proton fluence, Phi in p(+)/cm(2). The trapping depth dependence, however, did not agree well with the damage profile calculated...

  13. 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.

  14. 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.

  15. The evaluation of radiation damage parameter for CVD diamond

    Energy Technology Data Exchange (ETDEWEB)

    Grilj, V., E-mail: vgrilj@irb.hr [Division for Experimental Physics, Ruđer Bošković Institute, 10000 Zagreb (Croatia); Skukan, N.; Jakšić, M. [Division for Experimental Physics, Ruđer Bošković Institute, 10000 Zagreb (Croatia); Pomorski, M. [CEA-LIST, Diamond Sensors Laboratory, Gif-sur-Yvette F-91191 (France); Kada, W. [Division of Electronics and Informatics, Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515 (Japan); Kamiya, T.; Ohshima, T. [Japan Atomic Energy Agency (JAEA), Takasaki, Gunma 370-1292 (Japan)

    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.

  16. Modeling radiation damage to pixel sensors in the ATLAS detector

    CERN Document Server

    Ducourthial, Audrey; The ATLAS collaboration

    2017-01-01

    Silicon pixel detectors are at the core of the current and planned upgrade of the ATLAS detector at the Large Hadron Collider (LHC). As the closest detector component to the interaction point, these detectors will be subjected to a significant amount of radiation over their lifetime: prior to the High-Luminosity LHC (HL-LHC), the innermost layers will receive a fluence in excess of $10^{15}n_{eq}/cm^2$ and the HL-HLC detector upgrades must cope with an order of magnitude higher fluence integrated over their lifetimes. Simulating radiation damage is critical in order to make accurate predictions for current future detector performance that will enable searches for new particles and forces as well as precision measurements of Standard Model particles such as the Higgs boson. We present a digitization model that includes radiation damage effects to the ATLAS pixel sensors for the first time. In addition to thoroughly describing the setup, we present first predictions for basic pixel cluster properties alongside ...

  17. Modeling Radiation Damage to Pixel Sensors in the ATLAS Detector

    CERN Document Server

    Ducourthial, Audrey; The ATLAS collaboration

    2017-01-01

    Silicon pixel detectors are at the core of the current and planned upgrade of the ATLAS detector at the Large Hadron Collider (LHC). As the closest detector component to the interaction point, these detectors will be subjected to a significant amount of radiation over their lifetime: prior to the High-Luminosity LHC (HL-LHC), the innermost layers will receive a fluence in excess of $10^{15} n_{eq}/cm^2$ and the HL-HLC detector upgrades must cope with an order of magnitude higher fluence integrated over their lifetimes. Simulating radiation damage is critical in order to make accurate predictions for current future detector performance that will enable searches for new particles and forces as well as precision measurements of Standard Model particles such as the Higgs boson. We present a digitization model that includes radiation damage effects to the ATLAS pixel sensors for the first time. In addition to thoroughly describing the setup, we present first predictions for basic pixel cluster properties alongside...

  18. Contribution of endogenous and exogenous damage to the total radiation-induced damage in the bacterial spore

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, G.P.; Samuni, A.; Czapski, G.

    1980-01-01

    Radical scavengers such as polyethylene glycol 4000 and bovine albumin have been used to define the contribution of exogenous and endogenous damage to the total radiation-induced damage in aqueous buffered suspensions of Bacillus pumilus spores. The results indicate that this damage in the bacterial spore is predominantly endogenous.

  19. Chromatin Modifications and the DNA Damage Response to Ionizing Radiation

    Directory of Open Access Journals (Sweden)

    Tej K Pandita

    2013-01-01

    Full Text Available In order to survive, cells have evolved highly effective repair mechanisms to deal with the potentially lethal DNA damage produced by exposure to endogenous as well as exogenous agents. Ionizing radiation exposure induces highly lethal DNA damage, especially DNA double strand breaks (DSBs, that is sensed by the cellular machinery and then subsequently repaired by either of two different DSB repair mechanisms: 1 non-homologous end-joining (NHEJ, which re-ligates the broken ends of the DNA and 2 homologous recombination (HR, that employs an undamaged identical DNA sequence as a template, to maintain the fidelity of DNA repair. Repair of DSBs must occur within the natural context of the cellular DNA which, along with specific proteins, is organized to form chromatin, the overall structure of which can impede DNA damage site access by repair proteins. The chromatin complex is a dynamic structure and is known to change as required for ongoing cellular processes such as gene transcription or DNA replication. Similarly, during the process of DNA damage sensing and repair, chromatin needs to undergo several changes in order to facilitate accessibility of the repair machinery. Cells utilize several factors to modify the chromatin in order to locally open up the structure to reveal the underlying DNA sequence but posttranslational modification (PTMs of the histone components is one of the primary mechanisms. In this review, we will summarize chromatin modification by t

  20. 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.

  1. Long-term radiation damage to a spaceborne germanium spectrometer

    CERN Document Server

    Kurczynski, P; Hull, E L; Palmer, D; Harris, M J; Seifert, H; Teegarden, B J; Gehrels, N; Cline, T L; Ramaty, R; Sheppard, D; Madden, N W; Luke, P N; Cork, C P; Landis, D A; Malone, D F; Hurley, K

    1999-01-01

    The Transient Gamma-Ray Spectrometer aboard the Wind spacecraft in deep space has observed gamma-ray bursts and solar events for four years. The germanium detector in the instrument has gradually deteriorated from exposure to the approx 10 sup 8 p/cm sup 2 /yr(>100 MeV) cosmic-ray flux. Low-energy tailing and loss of efficiency, attributed to hole trapping and conversion of the germanium from n- to p-type as a result of crystal damage, were observed. Raising the detector bias voltage ameliorated both difficulties and restored the spectrometer to working operation. Together, these observations extend our understanding of the effects of radiation damage to include the previously unsuccessfully studied regime of long-term operation in space. (author)

  2. Simulation of neutron radiation damage in silicon semiconductor devices.

    Energy Technology Data Exchange (ETDEWEB)

    Shadid, John Nicolas; Hoekstra, Robert John; Hennigan, Gary Lee; Castro, Joseph Pete Jr.; Fixel, Deborah A.

    2007-10-01

    A code, Charon, is described which simulates the effects that neutron damage has on silicon semiconductor devices. The code uses a stabilized, finite-element discretization of the semiconductor drift-diffusion equations. The mathematical model used to simulate semiconductor devices in both normal and radiation environments will be described. Modeling of defect complexes is accomplished by adding an additional drift-diffusion equation for each of the defect species. Additionally, details are given describing how Charon can efficiently solve very large problems using modern parallel computers. Comparison between Charon and experiment will be given, as well as comparison with results from commercially-available TCAD codes.

  3. Radiation Damage to the Elements of the SIS300 Dipoles

    CERN Document Server

    Mustafin, Edil; Latysheva, Ludmila N; Moritz, Gebhard; Sobolevskiy, Nikolai; Walter, Gertrud

    2005-01-01

    Radiation damage to various elements of the cosine-theta type dipoles of the SIS300 synchrotron of the FAIR Project was calculated. Among the elements under consideration were the superconducting cable, insulating materials, and high-current by-pass protection diodes. The Monte-Carlo particle transport codes MARS and SHIELD were used to simulate propagation of the lost ions and protons, together with the products of nuclear interactions in the material of the elements. It was found that the lifetime of the protection diodes under irradiation is a more restrictive limit for the tolerable level of beam losses than the occurrence of magnet quenches.

  4. Damages by radiation in glasses; Danos por radiacion en vidrios

    Energy Technology Data Exchange (ETDEWEB)

    Olguin, F.; Gutierrez, C.; Cisniega, G.; Flores, J.H.; Golzarri, J.I.; Espinoza, G. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    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)

  5. 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).

  6. Multiscale physics of ion-induced radiation damage.

    Science.gov (United States)

    Surdutovich, Eugene; Solov'yov, A V

    2014-01-01

    This is a review of a multiscale approach to the physics of ion-beam cancer therapy, an approach suggested in order to understand the interplay of a large number of phenomena involved in the radiation damage scenario occurring on a range of temporal, spatial, and energy scales. We describe different effects that take place on different scales and play major roles in the scenario of interaction of ions with tissue. The understanding of these effects allows an assessment of relative biological effectiveness that relates the physical quantities, such as dose, to the biological values, such as the probability of cell survival.

  7. 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...

  8. 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.

  9. 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%.

  10. Readout techniques and radiation damage of undoped cesium iodide

    Energy Technology Data Exchange (ETDEWEB)

    Woody, C.L.; Levy, P.W.; Kierstead, J.A.; Skwarnicki, T.; Sobolewski, Z.; Goldberg, M.; Horwitz, N.; Souder, P.; Anderson, D.F. (Brookhaven National Lab., Upton, NY (USA); Syracuse Univ., NY (USA). Dept. of Physics; Fermi National Accelerator Lab., Batavia, IL (USA))

    1989-01-01

    Several readout techniques for undoped CsI have been studied which utilize the fast scintillation component for speed, and the high photon yield for good energy resolution. Quantum yields have been measured for samples up to 30 cm in length using photomultiplier tubes, wavelength shifters, and silicon photodiodes. A study has also been made of the scintillation properties of undoped CsI. It is found that the light output and decay time of the 310 nm fast component increases and the emission spectrum shifts to longer wavelengths at lower temperatures. The effects on the optical transmission and scintillation light output due to radiation damage from {sup 60}Co gamma rays has been measured for doses up to {approximately}10{sup 6} rad. It is found that the radiation resistance of undoped CsI is substantially higher than has been reported for thallium doped CsI. 16 refs., 11 figs., 3 tabs.

  11. Modeling Radiation Damage to Pixel Sensors in the ATLAS Detector

    CERN Document Server

    Nachman, Benjamin Philip; The ATLAS collaboration

    2017-01-01

    Silicon Pixel detectors are at the core of the current and planned upgrade of the ATLAS detector. As the detector in closest proximity to the interaction point, these detectors will be subjected to a significant amount of radiation over their lifetime: prior to the HL-LHC, the innermost layers will receive a fluence in excess of $10^{15}$ 1 MeV $n_\\mathrm{eq}/\\mathrm{cm}^2$ and the HL-LHC detector upgrades must cope with an order of magnitude higher fluence integrated over their lifetimes. This talk presents a digitization model that includes radiation damage effects to the ATLAS Pixel sensors for the first time. After a thorough description of the setup, predictions for basic Pixel cluster properties are presented alongside first validation studies with Run 2 collision data.

  12. Radiation damage effects in standard float zone silicon diodes

    Energy Technology Data Exchange (ETDEWEB)

    Pascoalino, Kelly C.; Camargo, Fabio; Barbosa, Renata F.; Goncalves, Josemary A.C.; Tobias, Carmen C.B., E-mail: ccbueno@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2009-07-01

    The aim of this work was to study the radiation damage effects on the electrical properties of standard float zone diodes (STFZ). Such effects were evaluated by measuring the current and capacitance of these devices as a function of the reverse voltage. For comparison, current and capacitance measurements were carried out with a non-irradiated STFZ device. The irradiation was performed in the Radiation Technology Center (CTR) at IPEN/CNEN-SP using a {sup 60}Co irradiator (Gammacell 220 - Nordion) with a dose rate of about 2.2 kGy/h. Samples were irradiated at room temperature in steps variable from 50 kGy up 140 kGy which lead to an accumulated dose of 460 kGy. The results obtained have shown that the upper dose limit for a 'damageless' STFZ diode is about 50 kGy. (author)

  13. 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.

  14. 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

  15. Genetic damage in subjects exposed to radiofrequency radiation.

    Science.gov (United States)

    Verschaeve, Luc

    2009-01-01

    Despite many research efforts and public debate there is still great concern about the possible adverse effects of radiofrequency (RF) radiation on human health. This is especially due to the enormous increase of wireless mobile telephones and other telecommunication devices throughout the world. The possible genetic effects of mobile phone radiation and other sources of radiofrequencies constitute one of the major points of concern. In the past several review papers were published on laboratory investigations that were devoted to in vitro and in vivo animal (cyto)genetic studies. However, it may be assumed that some of the most important observations are those obtained from studies with individuals that were exposed to relatively high levels of radiofrequency radiation, either as a result of their occupational activity or as frequent users of radiofrequency emitting tools. In this paper the cytogenetic biomonitoring studies of RF-exposed humans are reviewed. A majority of these studies do show that RF-exposed individuals have increased frequencies of genetic damage (e.g., chromosomal aberrations) in their lymphocytes or exfoliated buccal cells. However, most of the studies, if not all, have a number of shortcomings that actually prevents any firm conclusion. Radiation dosimetry was lacking in all papers, but some of the investigations were flawed by much more severe imperfections. Large well-coordinated multidisciplinary investigations are needed in order to reach any robust conclusion.

  16. Properties and recrystallization of radiation damaged pyrochlore and titanite

    Energy Technology Data Exchange (ETDEWEB)

    Zietlow, Peter

    2016-11-02

    Radiation damage in minerals is caused by the alpha-decay of incorporated radionuclides, such as U and Th and their decay products. The effect of thermal annealing (400-1400 K) on radiation-damaged pyrochlores has been investigated by Raman scattering, X-ray powder diffraction (XRD), and combined differential scanning calorimetry/thermogravimetry (DSC/TG) (Zietlow et al., in print). The analysis of three natural radiation-damaged pyrochlore samples from Miass/Russia (6.4 wt% Th, 23.1.10{sup 18} a-decay events per gram (dpg)), Zlatoust/Russia (6.3 wt% Th, 23.1.10{sup 18} dpg), Panda Hill/Tanzania (1.6 wt% Th, 1.6.10{sup 18} dpg), and Blue River/Canada (10.5 wt% U, 115.4.10{sup 18} dpg), are compared with a crystalline reference pyrochlore from Schelingen (Germany). The type of structural recovery depends on the initial degree of radiation damage (Panda Hill 28 %, Blue River 85 %, Zlatoust and Miass 100 % according to XRD), as the recrystallization temperature increases with increasing degree of amorphization. Raman spectra indicate reordering on the local scale during annealing-induced recrystallization. As Raman modes around 800 cm{sup -1} are sensitive to radiation damage (Vandenborre and Husson 1983, Moll et al. 2011), the degree of local order was deduced from the ratio of the integrated intensities of the sum of the Raman bands between 605 and 680 cm{sup -1} devided by the sum of the integrated intensities of the bands between 810 and 860 cm{sup -1}. The most radiation damaged pyrochlores (Miass and Zlatoust) show an abrupt recovery of both, its short- (Raman) and long-range order (X-ray) between 800 and 850 K. The volume decrease upon recrystallization in Zlatoust pyrochlore was large enough to crack the sample repeatedly. In contrast, the weakly damaged pyrochlore (Panda Hill) begins to recover at considerably lower temperatures (near 500 K), extending over a temperature range of ca. 300 K, up to 800 K (Raman). The pyrochlore from Blue River shows in its

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

    Science.gov (United States)

    Denifl, S.; Garcia, G.; Huber, B. A.; Marinković, B. P.; Mason, N.; Postler, J.; Rabus, H.; Rixon, G.; Solov'yov, A. V.; Suraud, E.; Yakubovich, A. V.

    2013-06-01

    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.

  18. DNA Damage by Radiation in Tradescantia Leaf Cells

    Energy Technology Data Exchange (ETDEWEB)

    Han, Min; Hyun, Kyung Man; Ryu, Tae Ho; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Advanced Radiation Technology Institute, Jeongeup (Korea, Republic of); Nili, Mohammad [Dawnesh Radiation Research Institute, Barcelona (Spain)

    2010-04-15

    The comet assay is currently used in different areas of biological sciences to detect DNA damage. The comet assay, due to its simplicity, sensitivity and need of a few cells, is ideal as a short-term genotoxicity test. The comet assay can theoretically be applied to every type of eukaryotic cell, including plant cells. Plants are very useful as monitors of genetic effects caused by pollution in the atmosphere, water and soil. Tradescantia tests are very useful tools for screening the mutagenic potential in the environment. Experiments were conducted to study the genotoxic effects of ionizing radiations on the genome integrity, particularly of Tradescantia. The increasingly frequent use of Tradescantia as a sensitive environmental bioindicator of genotoxic effects. This study was designed to assess the genotoxicity of ionizing radiation using Tradescnatia-comet assay. The development of comet assay has enabled investigators to detect DNA damage at the levels of cells. To adapt this assay to plant cells, nuclei were directly obtained from Tradescantia leaf samples. A significant dose-dependent increase in the average tail moment values over the negative control was observed. Recently the adaptation of this technique to plant cells opens new possibilities for studies in variety area. The future applications of the comet assay could impact some other important areas, certainly, one of the limiting factors to its utility is the imagination of the investigator.

  19. Radiation damage in soft X-ray microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.; Morin, C.; Li, L. [Department of Chemistry and Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON, L8S 4M1 (Canada); Hitchcock, A.P. [Department of Chemistry and Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON, L8S 4M1 (Canada)], E-mail: aph@mcmaster.ca; Scholl, A.; Doran, A. [Advanced Light Source, Berkeley Lab, Berkeley, CA 94720 (United States)

    2009-03-15

    The rates of chemical transformation by radiation damage of polystyrene (PS), poly(methyl methacrylate) (PMMA), and fibrinogen (Fg) in a X-ray photoemission electron microscope (X-PEEM) and in a scanning transmission X-ray microscope (STXM) have been measured quantitatively using synchrotron radiation. As part of the method of dose evaluation in X-PEEM, the characteristic (1/e) sampling depth of X-PEEM for polystyrene in the C 1s region was measured to be 4 {+-} 1 nm. Critical doses for chemical change as monitored by changes in the X-ray absorption spectra are 80 (12), 280 (40) and 1230 (180) MGy (1 MGy = 6.242*{rho} eV/nm{sup 3}, where {rho} is the polymer density in g/cm{sup 3}) at 300 eV photon energy for PMMA, Fg and PS, respectively. The critical dose for each material is comparable in X-PEEM and STXM and the values cited are thus the mean of the values determined by X-PEEM and STXM. C 1s, N 1s and O 1s spectroscopy of the damaged materials is used to gain insight into the chemical changes that soft X-rays induce in these materials.

  20. Self-radiation damage in plutonium and uranium mixed dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Masato, E-mail: kato.masato@jaea.go.j [Japan Atomic Energy Agency, 4-33 Muramatu, Tokai-Mura, Naka-gun, Ibaraki 319-1194 (Japan); Komeno, Akira [Japan Atomic Energy Agency, 4-33 Muramatu, Tokai-Mura, Naka-gun, Ibaraki 319-1194 (Japan); Uno, Hiroki; Sugata, Hiromasa [Inspection Development Company, 4-33 Muramatu, Tokai-Mura, Naka-gun, Ibaraki 319-1194 (Japan); Nakae, Nobuo [Japan Atomic Energy Agency, 4-33 Muramatu, Tokai-Mura, Naka-gun, Ibaraki 319-1194 (Japan); Japan Nuclear Energy Safety Organization, TOKYU REIT Toranomon Bldg, 3-17-1, Toranomon, Minato-ku, Tokyo 105-0001 (Japan); Konashi, Kenji [Tohoku University, 2145-2, Narita, Oarai-machi, Ibaraki 311-1313 (Japan); Kashimura, Motoaki [Japan Atomic Energy Agency, 4-33 Muramatu, Tokai-Mura, Naka-gun, Ibaraki 319-1194 (Japan)

    2009-08-15

    In plutonium compounds, the lattice parameter increases due to self-radiation damage by alpha-decay of plutonium isotopes. The lattice parameter change and its thermal recovery in plutonium and uranium mixed dioxide (MOX) were studied. The lattice parameter for samples of MOX powders and pellets that had been left in the air for up to 32 years was measured. The lattice parameter increased and was saturated at about 0.29%. The change in lattice parameter was formulated as a function of self-radiation dose. Three stages in the thermal recovery of the damage were observed in temperature ranges of below 673 K, 673-1073 K and above 1073 K. The activation energies in each recovery stage were estimated to be 0.12, 0.73 and 1.2 eV, respectively, and the corresponding mechanism for each stage was considered to be the recovery of the anion Frenkel defect, the cation Frenkel defect and a defect connected with helium, respectively.

  1. Imperfection and radiation damage in protein crystals studied with coherent radiation

    Energy Technology Data Exchange (ETDEWEB)

    Nave, Colin, E-mail: colin.nave@diamond.ac.uk [Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot OX11 0DE (United Kingdom); Sutton, Geoff [Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); Evans, Gwyndaf; Owen, Robin; Rau, Christoph [Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot OX11 0DE (United Kingdom); Robinson, Ian [University College London, 17–19 Gordon Street, London WC1H 0AH (United Kingdom); Stuart, David Ian [Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot OX11 0DE (United Kingdom)

    2016-01-01

    Coherent diffraction observations from polyhedra crystals at cryotemperature are reported. Information is obtained about the lattice strain and the changes with radiation damage. Fringes and speckles occur within diffraction spots when a crystal is illuminated with coherent radiation during X-ray diffraction. The additional information in these features provides insight into the imperfections in the crystal at the sub-micrometre scale. In addition, these features can provide more accurate intensity measurements (e.g. by model-based profile fitting), detwinning (by distinguishing the various components), phasing (by exploiting sampling of the molecular transform) and refinement (by distinguishing regions with different unit-cell parameters). In order to exploit these potential benefits, the features due to coherent diffraction have to be recorded and any change due to radiation damage properly modelled. Initial results from recording coherent diffraction at cryotemperatures from polyhedrin crystals of approximately 2 µm in size are described. These measurements allowed information about the type of crystal imperfections to be obtained at the sub-micrometre level, together with the changes due to radiation damage.

  2. Sunlight and Vitamin D

    Science.gov (United States)

    Wacker, Matthias; Holick, Michael F.

    2013-01-01

    Vitamin D is the sunshine vitamin that has been produced on this earth for more than 500 million years. During exposure to sunlight 7-dehydrocholesterol in the skin absorbs UV B radiation and is converted to previtamin D3 which in turn isomerizes into vitamin D3. Previtamin D3 and vitamin D3 also absorb UV B radiation and are converted into a variety of photoproducts some of which have unique biologic properties. Sun induced vitamin D synthesis is greatly influenced by season, time of day, latitude, altitude, air pollution, skin pigmentation, sunscreen use, passing through glass and plastic, and aging. Vitamin D is metabolized sequentially in the liver and kidneys into 25-hydroxyvitamin D which is a major circulating form and 1,25-dihydroxyvitamin D which is the biologically active form respectively. 1,25-dihydroxyvitamin D plays an important role in regulating calcium and phosphate metabolism for maintenance of metabolic functions and for skeletal health. Most cells and organs in the body have a vitamin D receptor and many cells and organs are able to produce 1,25-dihydroxyvitamin D. As a result 1,25-dihydroxyvitamin D influences a large number of biologic pathways which may help explain association studies relating vitamin D deficiency and living at higher latitudes with increased risk for many chronic diseases including autoimmune diseases, some cancers, cardiovascular disease, infectious disease, schizophrenia and type 2 diabetes. A three-part strategy of increasing food fortification programs with vitamin D, sensible sun exposure recommendations and encouraging ingestion of a vitamin D supplement when needed should be implemented to prevent global vitamin D deficiency and its negative health consequences. PMID:24494042

  3. Radiation damage of hollandite in multiphase ceramic waste forms

    Science.gov (United States)

    Clark, Braeden M.; Tumurgoti, Priyatham; Sundaram, S. K.; Amoroso, Jake W.; Marra, James C.; Shutthanandan, Vaithiyalingam; Tang, Ming

    2017-10-01

    Radiation damage was simulated in multiphase titanate-based ceramic waste forms using an ion accelerator to generate high energy alpha particles (He+) and an ion implanter to generate 7 MeV gold (Au3+) particles. X-ray diffraction and transmission electron microscopy were used to characterize the damaged surfaces and nearby regions. Simulated multiphase ceramic waste forms were prepared using two processing methods: spark plasma sintering and melt-processing. Both processing methods produced ceramics with similar phase assemblages consisting of hollandite-, zirconolite/pyrochlore-, and perovskite-type phases. The measured heavy ion (Au3+) penetration depth was less in spark plasma sintered samples than in melt-processed samples. Structural breakdown of the hollandite phase occurred under He+ irradiation indicated by the presence of x-ray diffraction peaks belonging to TiO2, BaTiO5, and other hollandite related phases (Ba2Ti9O20). The composition of the constituent hollandite phase affected the extent of damage induced by Au3+ ions.

  4. LNL irradiation facilities for radiation damage studies on electronic devices

    Science.gov (United States)

    Bisello, D.; Candelori, A.; Giubilato, P.; Mattiazzo, S.; Pantano, D.; Silvestrin, L.; Tessaro, M.; Wyss, J.

    2016-11-01

    In this paper we will review the wide range of irradiation facilities installed at the INFN Legnaro National Laboratories and routinely used for radiation damage studies on silicon detectors, electronic components and systems. The SIRAD irradiation facility, dedicated to Single Event Effect (SEE) and bulk damage studies, is installed at the 14MV Tandem XTU accelerator and can deliver ion beams from H up to Au in the energy range from 28MeV to 300MeV. An Ion Electron Emission Microscope, also installed at SIRAD, allows SEE testing with micrometric sensitivity. For total dose tests, two facilities are presently available: an X-rays source and a 60Co γ -ray source. The 7MV Van de Graaff CN accelerator provides 1H beams in the energy range 2-7MeV and currents up to few μA for both total dose and bulk damage studies. At this facility, very high dose rates (up to ˜ 100 krad/s (SiO2)) can be achieved. Finally, also neutron beams are available, produced at the CN accelerator, by the reaction d + Be ⇒ n + B.

  5. Mitigating radiation damage of single photon detectors for space applications

    Energy Technology Data Exchange (ETDEWEB)

    Anisimova, Elena; Higgins, Brendon L.; Bourgoin, Jean-Philippe [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada); Cranmer, Miles [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); Choi, Eric [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); Magellan Aerospace, Ottawa, ON (Canada); Hudson, Danya; Piche, Louis P.; Scott, Alan [Honeywell Aerospace (formerly COM DEV Ltd.), Ottawa, ON (Canada); Makarov, Vadim [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada); University of Waterloo, Department of Electrical and Computer Engineering, Waterloo, ON (Canada); Jennewein, Thomas [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada); Canadian Institute for Advanced Research, Quantum Information Science Program, Toronto, ON (Canada)

    2017-12-15

    Single-photon detectors in space must retain useful performance characteristics despite being bombarded with sub-atomic particles. Mitigating the effects of this space radiation is vital to enabling new space applications which require high-fidelity single-photon detection. To this end, we conducted proton radiation tests of various models of avalanche photodiodes (APDs) and one model of photomultiplier tube potentially suitable for satellite-based quantum communications. The samples were irradiated with 106 MeV protons at doses approximately equivalent to lifetimes of 0.6, 6, 12 and 24 months in a low-Earth polar orbit. Although most detection properties were preserved, including efficiency, timing jitter and afterpulsing probability, all APD samples demonstrated significant increases in dark count rate (DCR) due to radiation-induced damage, many orders of magnitude higher than the 200 counts per second (cps) required for ground-to-satellite quantum communications. We then successfully demonstrated the mitigation of this DCR degradation through the use of deep cooling, to as low as -86 C. This achieved DCR below the required 200 cps over the 24 months orbit duration. DCR was further reduced by thermal annealing at temperatures of +50 to +100 C. (orig.)

  6. 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

  7. 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.

  8. 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.)

  9. Can Natural Sunlight Induce Coherent Exciton Dynamics?

    CERN Document Server

    Olšina, Jan; Wang, Chen; Cao, Jianshu

    2014-01-01

    Excitation of a model photosynthetic molecular aggregate by incoherent sunlight is systematically examined. For a closed system, the excited state coherence induced by the sunlight oscillates with an average amplitude that is inversely proportional to the excitonic gap, and reaches a stationary amplitude that depends on the temperature and coherence time of the radiation field. For an open system, the light-induced dynamical coherence relaxes to a static coherence determined by the non-canonical thermal distribution resulting from the entanglement with the phonon bath. The decay of the excited state population to the common ground state establishes a non-equilibrium steady-state flux driven by the sunlight, and it defines a time window to observe the transition from dynamical to static coherence. For the parameters relevant to photosynthetic systems, the exciton dynamics initiated by the sunlight exhibits a non-negligible amount of dynamical coherence (quantum beats) on the sub-picosecond timescale; however, ...

  10. Hydration and transparency of the rabbit cornea irradiated with UVB-doses of 0.25 J/cm(2) and 0.5 J/cm(2) compared with equivalent UVB radiation exposure reaching the human cornea from sunlight.

    Science.gov (United States)

    Cejka, Cestmír; Ardan, Taras; Sirc, Jakub; Michálek, Jiří; Beneš, Jiří; Brůnová, Blanka; Rosina, Jozef

    2011-07-01

    Exposure of the cornea to UV radiation from sunlight evokes intraocular inflammation, photokeratitis. Photokeratitis is caused by UVB radiation. It is accompanied by changes of corneal hydration and light absorption. The aim of this study was to examine the effect of two UVB doses on corneal optics in rabbits and to compare these UVB doses with the equivalent exposure of UVB radiation reaching the human cornea from sunlight. Rabbit corneas were irradiated with a daily UVB dose of 0.25 J/cm(2) or 0.5 J/cm(2) for 4 days. One day after finishing the irradiations the rabbits were sacrificed and corneal light absorption measured using our spectrophotometrical method. Corneal hydration was examined using an ultrasonic Pachymeter every experimental day before the irradiation procedure and the last day before sacrificing the animals. Changes in corneal optics appeared after the repeated exposure of the cornea to a UVB dose of 0.25 J/ cm(2) and massively increased after the repeated exposure of the cornea to a UVB dose of 0.5 J/cm(2). The first significant changes in corneal hydration appeared after a single exposure of the cornea to a UVB dose of 0.25 J/cm(2). Changes in corneal hydration appeared after the exposure of the rabbit cornea to a single UVB dose equivalent to 2.6 hours of solar UVB radiation reaching the human cornea, as measured by UVB sensors embedded in the eyes of mannequin heads facing the sun on a beach at noon in July. Repeated exposure of the rabbit cornea to the same UVB dose evoked profound changes in corneal optics. Although comparison of experimental and outdoor conditions are only approximate, the results in rabbits point to the danger for the human eye from UVB radiation when short stays in sunlight are repeated for several consecutive days without UV protection.

  11. 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

  12. Radiation Damage Studies with Hadrons on Materials and Electronics

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, J

    2004-07-01

    Many materials and electronics need to be tested for the radiation environment expected at linear colliders (LC) where the accelerator and detectors will be subjected to large fluences of hadrons, leptons and {gamma}'s over their life[1]. Examples are NdFeB magnets considered for the damping rings and final focus, electronic and electro-optical devices to be utilized in detector readout and accelerator controls and CCDs required for the vertex detector. Effects of {gamma}'s on many materials have been presented[2] and our understanding of the situation for rare earth permanent magnets at PAC2003[3]. Here we give first measurements of the fast neutron, stepped doses at the UC Davis McClellan Nuclear Reactor Center (UCD MNRC) together with the induced radioactivities. Damage appears to be proportional to the distances between the operating point and H{sub ci}.

  13. Radiation damage/activity calculation for CSNS target station

    Science.gov (United States)

    Yin, W.; Liang, T. J.; Yu, Q. Z.; Jia, X. J.

    2010-03-01

    The radiation damages have been performed for Chinese spallation neutron source (CSNS) target center components that relies on Monte Carlo simulation code MCNPX. During the calculation, Bertini intranuclear cascade model, three level-density formulation GCCI, and multistage pre-equilibrium model MPM on which are provided within MCNPX are employed. We calculate the displacement per atom (DPA) and afterheat of the tungsten target, the stainless steel target vessel window and the aluminum alloy moderator vessel. As a hundred kW-level source, these spallation center components have the lifetime more than 5 year. We also give the activity for the T0 chopper of the beam line HIPD to get the primary data for making out a maintenance scenario.

  14. Chromatin compaction protects genomic DNA from radiation damage.

    Directory of Open Access Journals (Sweden)

    Hideaki Takata

    Full Text Available Genomic DNA is organized three-dimensionally in the nucleus, and is thought to form compact chromatin domains. Although chromatin compaction is known to be essential for mitosis, whether it confers other advantages, particularly in interphase cells, remains unknown. Here, we report that chromatin compaction protects genomic DNA from radiation damage. Using a newly developed solid-phase system, we found that the frequency of double-strand breaks (DSBs in compact chromatin after ionizing irradiation was 5-50-fold lower than in decondensed chromatin. Since radical scavengers inhibited DSB induction in decondensed chromatin, condensed chromatin had a lower level of reactive radical generation after ionizing irradiation. We also found that chromatin compaction protects DNA from attack by chemical agents. Our findings suggest that genomic DNA compaction plays an important role in maintaining genomic integrity.

  15. Evaluating experimental molecular physics studies of radiation damage in DNA*

    Science.gov (United States)

    Śmiałek, Małgorzata A.

    2016-11-01

    The field of Atomic and Molecular Physics (AMP) is a mature field exploring the spectroscopy, excitation, ionisation of atoms and molecules in all three phases. Understanding of the spectroscopy and collisional dynamics of AMP has been fundamental to the development and application of quantum mechanics and is applied across a broad range of disparate disciplines including atmospheric sciences, astrochemistry, combustion and environmental science, and in central to core technologies such as semiconductor fabrications, nanotechnology and plasma processing. In recent years the molecular physics also started significantly contributing to the area of the radiation damage at molecular level and thus cancer therapy improvement through both experimental and theoretical advances, developing new damage measurement and analysis techniques. It is therefore worth to summarise and highlight the most prominent findings from the AMP community that contribute towards better understanding of the fundamental processes in biologically-relevant systems as well as to comment on the experimental challenges that were met for more complex investigation targets. Contribution to the Topical Issue "Low-Energy Interactions related to Atmospheric and Extreme Conditions", edited by S. Ptasinska, M. Smialek-Telega, A. Milosavljevic, B. Sivaraman.

  16. 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.)

  17. Effects of lactic bacteria on immunological activation and radiation damage

    Energy Technology Data Exchange (ETDEWEB)

    Monzen, Hajime; Yuki, Rumio [Otsu Red Cross Hospital, Shiga (Japan); Gu, Yeunhwa; Hasegawa, Takeo [Suzuka Univ. of Medical Science, Mie (Japan). Graduate School

    2003-03-01

    Although some studies have suggested that certain substances, such as vitamins and glucan, found in natural food products may have protective effect against radiation injuries, no substance is used practically as radioprotectors. Safe radioprotectors without side effects are, however, yet to see. Enterococcus faecalis (Ef) in intestines is known to enhance immunity of the host as a biological response modifier. In this report, we have examined the radiation protection effect of Ef using C3H mice and assessed the effect of Ef on the natural killer (NK) cells activity of the splenic cells in the mice. Less body weight losses after irradiation were observed among Ef injection groups, in comparison with control groups. Our data showed a strong tendency to prolong the surviving fraction among the groups with the Ef injection. Hence, the Ef treatment appeared to have protected mucosal damage caused by the X-ray irradiation. The NK cells activities were markedly enhanced after the Ef injection as well. With the evidence mentioned above, we conclude that the Ef may have positive effect on patients who undergo a radiotherapy. (author)

  18. Study of the radiation damage of silicon photomultipliers

    Energy Technology Data Exchange (ETDEWEB)

    Nitschke, Michael; Chmill, Valery; Garutti, Erika; Klanner, Robert; Schwandt, Joern [Institute for Experimental Physics, Hamburg University, Luruper Chaussee 149, D-22761 Hamburg (Germany)

    2016-07-01

    Radiation damage significantly changes the performance of silicon photomultipliers (SiPM). In this work, we first have characterized KETEK SiPMs with a pixel size of 15 x 15 μm{sup 2} using I-V (current-voltage), C/G-V/f (capacitance/impedance-voltage/frequency) and Q-V (charge-voltage) measurements with and without illumination with blue light of 470 nm from an LED. The SiPM parameters determined are DCR (dark count rate), relative PDE (photon detection efficiency), G (Gain), XT (cross-talk), Geiger breakdown characteristics, C{sub pix} (pixel capacitance) and R{sub q} (quenching resistance). Following this first characterization, the SiPMs were irradiated using reactor neutrons with fluences of 10{sup 9}, 10{sup 10}, 10{sup 11}, 5 . 10{sup 11}, and 10{sup 12} n/cm{sup 2}. Afterwards, the same measurements were repeated, and the dependence of the SiPM parameters on neutron fluence was determined. The results are used to optimize the radiation tolerance of SiPMs.

  19. Use of Displacement Damage Dose in an Engineering Model of GaAs Solar Cell Radiation Damage

    Science.gov (United States)

    Morton, T. L.; Chock, R.; Long, K. J.; Bailey, S.; Messenger, S. R.; Walters, R. J.; Summers, G. P.

    2005-01-01

    Current methods for calculating damage to solar cells are well documented in the GaAs Solar Cell Radiation Handbook (JPL 96-9). An alternative, the displacement damage dose (D(sub d)) method, has been developed by Summers, et al. This method is currently being implemented in the SAVANT computer program.

  20. Radiation Damage and Fission Product Release in Zirconium Nitride

    Energy Technology Data Exchange (ETDEWEB)

    Egeland, Gerald W. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States)

    2005-08-29

    Zirconium nitride is a material of interest to the AFCI program due to some of its particular properties, such as its high melting point, strength and thermal conductivity. It is to be used as an inert matrix or diluent with a nuclear fuel based on transuranics. As such, it must sustain not only high temperatures, but also continuous irradiation from fission and decay products. This study addresses the issues of irradiation damage and fission product retention in zirconium nitride through an assessment of defects that are produced, how they react, and how predictions can be made as to the overall lifespan of the complete nuclear fuel package. Ion irradiation experiments are a standard method for producing radiation damage to a surface for observation. Cryogenic irradiations are performed to produce the maximum accumulation of defects, while elevated temperature irradiations may be used to allow defects to migrate and react to form clusters and loops. Cross-sectional transmission electron microscopy and grazing-incidence x-ray diffractometry were used in evaluating the effects that irradiation has on the crystal structure and microstructure of the material. Other techniques were employed to evaluate physical effects, such as nanoindentation and helium release measurements. Results of the irradiations showed that, at cryogenic temperatures, ZrN withstood over 200 displacements per atom without amorphization. No significant change to the lattice or microstructure was observed. At elevated temperatures, the large amount of damage showed mobility, but did not anneal significantly. Defect clustering was possibly observed, yet the size was too small to evaluate, and bubble formation was not observed. Defects, specifically nitrogen vacancies, affect the mechanical behavior of ZrN dramatically. Current and previous work on dislocations shows a distinct change in slip plane, which is evidence of the bonding characteristics. The stacking-fault energy changes dramatically with

  1. Multiscale approach to radiation damage induced by ion beams: complex DNA damage and effects of thermal spikes

    CERN Document Server

    Surdutovich, E; Solov'yov, A V

    2010-01-01

    We present the latest advances of the multiscale approach to radiation damage caused by irradiation of a tissue with energetic ions and report the most recent advances in the calculations of complex DNA damage and the effects of thermal spikes on biomolecules. The multiscale approach aims to quantify the most important physical, chemical, and biological phenomena taking place during and following irradiation with ions and provide a better means for clinically-necessary calculations with adequate accuracy. We suggest a way of quantifying the complex clustered damage, one of the most important features of the radiation damage caused by ions. This method can be used for the calculation of irreparable DNA damage. We include thermal spikes, predicted to occur in tissue for a short time after ion's passage in the vicinity of the ions' tracks in our previous work, into modeling of the thermal environment for molecular dynamics analysis of ubiquitin and discuss the first results of these simulations.

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

    Energy Technology Data Exchange (ETDEWEB)

    Tsutsumi, Nobuo; Rakugi, Masami; Kusamura, Yayoi; Ochiai, Nobuyuki; Saito, Takahiro (Osaka Univ. (Japan). School of Dentistry)

    1983-12-01

    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 smaller 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.

  3. Comparison between cytogenetic damage induced in human lymphocytes by environmental chemicals or radiation

    Energy Technology Data Exchange (ETDEWEB)

    Cebulska-Wasilewska, A. [Institute of Nuclear Physics, Cracow (Poland)

    1997-12-31

    Author compared cytogenetic effects of chemicals (benzene and the member at benzene related compounds) and ionizing radiation on the human lymphocytes. Levels of various types of cytogenetic damage observed among people from petroleum plants workers groups are similar to the levels of damages detected in the blood of people suspected of the accidental exposure to a radiation source

  4. 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.

  5. 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.

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

    Science.gov (United States)

    Sutherland, Betsy M.; Bennett, Paula V.; Cintron-Torres, Nela; Hada, Megumi; Trunk, John; Monteleone, Denise; Sutherland, John C.; Laval, Jacques; Stanislaus, Marisha; Gewirtz, Alan

    2002-01-01

    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, DSB are about 30% of the total of complex damages, and the levels of DSBs and oxidized pyrimidine clusters are similar. The dose responses for 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.

  7. PWO crystals for CMS electromagnetic calorimeter studies of the radiation damage kinetics

    CERN Document Server

    Drobychev, G Yu; Dormenev, V; Korzhik, M; Lecoq, P; Lopatic, A; Nédélec, P; Peigneux, J P; Sillou, D

    2005-01-01

    Kinetics of radiation damage of the PWO crystals under irradiation and recovery were studied. Crystals were irradiated with dose corresponding to average one expected in the electromagnetic calorimeter (working dose irradiation). Radiation damage and recovery were monitored through measurements of PWO optical transmission. An approach is proposed which allows evaluating the influence of the PWO crystals properties on the statistical term in the energy resolution of the electromagnetic calorimeter. The analysis also gives important information about the nature of the radiation damage mechanism in scintillation crystals. The method was used during development of technology of the mass production of radiation hard crystals and during development of methods for crystals certification

  8. Review of radiation damage studies on DNW CMOS MAPS

    Science.gov (United States)

    Traversi, G.; Gaioni, L.; Manazza, A.; Manghisoni, M.; Ratti, L.; Re, V.; Zucca, S.; Bettarini, S.; Rizzo, G.; Morsani, F.; Bosisio, L.; Rashevskaya, I.; Cindro, V.

    2013-12-01

    Monolithic active pixel sensors fabricated in a bulk CMOS technology with no epitaxial layer and standard resistivity (10 Ω cm) substrate, featuring a deep N-well as the collecting electrode (DNW MAPS), have been exposed to γ-rays, up to a final dose of 10 Mrad (SiO2), and to neutrons from a nuclear reactor, up to a total 1 MeV neutron equivalent fluence of about 3.7 ·1013cm-2. The irradiation campaign was aimed at studying the effects of radiation on the most significant parameters of the front-end electronics and on the charge collection properties of the sensors. Device characterization has been carried out before and after irradiations. The DNW MAPS irradiated with 60Co γ-rays were also subjected to high temperature annealing (100 °C for 168 h). Measurements have been performed through a number of different techniques, including electrical characterization of the front-end electronics and of DNW diodes, laser stimulation of the sensors and tests with 55Fe and 90Sr radioactive sources. This paper reviews the measurement results, their relation with the damage mechanisms underlying performance degradation and provides a new comparison between DNW devices and MAPS fabricated in a CMOS process with high resistivity (1 kΩ cm) epitaxial layer.

  9. 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.

  10. Current ideas to reduce or salvage radiation damage to salivary glands

    NARCIS (Netherlands)

    Vissink, A; van Luijk, P; Langendijk, J A; Coppes, R P

    2015-01-01

    Radiation-induced hyposalivation is still a major problem after radiotherapy for head and neck cancer. Current and promising new thoughts to reduce or salvage radiation damage to salivary gland tissue are explored. The main cause underlying radiation-induced hyposalivation is a lack of functional sa

  11. Radiation damage studies related to nuclear waste forms

    Energy Technology Data Exchange (ETDEWEB)

    Gray, W.J.; Wald, J.W.; Turcotte, R.P.

    1981-12-01

    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, Gd/sub 2/Ti/sub 2/O/sub 7/ (pyrochlore) and CaZrTi/sub 2/O/sub 7/ (zirconolite), of relative importance to current waste forms were studied independently by doping with /sup 244/Cm 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 ..delta..V/V/sub 0/ = 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 Gd/sub 2/Ti/sub 2/O/sub 7/ and CaZrTi/sub 2/O/sub 7/. The later material exhibited anisotropic behavior in which the expansion of the monoclinic cell in the c/sub 0/ direction was over five times that of the a/sub 0/ 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 /sup 134/Cs, 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.

  12. Recent radiation damage studies and developments of the Marlowe code

    Science.gov (United States)

    Ortiz, C. J.; Souidi, A.; Becquart, C. S.; Domain, C.; Hou, M.

    2014-07-01

    Radiation damage in materials relevant to applications evolves over time scales spanning from the femtosecond - the characteristic time for an atomic collision - to decades - the aging time expected for nuclear materials. The relevant kinetic energies of atoms span from thermal motion to the MeV range.The question motivating this contribution is to identify the relationship between elementary atomic displacements triggered by irradiation and the subsequent microstructural evolution of metals in the long term. The Marlowe code, based on the binary collision approximation (BCA) is used to simulate the sequences of atomic displacements generated by energetic primary recoils and the Object Kinetic Monte Carlo code LAKIMOCA, parameterized on a range of ab initio calculations, is used to predict the subsequent long-term evolution of point defect and clusters thereof. In agreement with full Molecular Dynamics, BCA displacement cascades in body-centered cubic (BCC) Fe and a face-centered cubic (FCC) Febond Nibond Cr alloy display recursive properties that are found useful for predictions in the long term.The case of defects evolution in W due to external irradiation with energetic H and He is also discussed. To this purpose, it was useful to extend the inelastic energy loss model available in Marlowe up to the Bethe regime. The last version of the Marlowe code (version 15) was delivered before message passing instructions softwares (such as MPI) were available but the structure of the code was designed in such a way to permit parallel executions within a distributed memory environment. This makes possible to obtain N different cascades simultaneously using N independent nodes without any communication between processors. The parallelization of the code using MPI was recently achieved by one author of this report (C.J.O.). Typically, the parallelized version of Marlowe allows simulating millions of displacement cascades using a limited number of processors (<64) within only

  13. Quantifying radiation damage in biomolecular small-angle X-ray scattering.

    Science.gov (United States)

    Hopkins, Jesse B; Thorne, Robert E

    2016-06-01

    Small-angle X-ray scattering (SAXS) is an increasingly popular technique that provides low-resolution structural information about biological macromolecules in solution. Many of the practical limitations of the technique, such as minimum required sample volume, and of experimental design, such as sample flow cells, are necessary because the biological samples are sensitive to damage from the X-rays. Radiation damage typically manifests as aggregation of the sample, which makes the collected data unreliable. However, there has been little systematic investigation of the most effective methods to reduce damage rates, and results from previous damage studies are not easily compared with results from other beamlines. Here a methodology is provided for quantifying radiation damage in SAXS to provide consistent results between different experiments, experimenters and beamlines. These methods are demonstrated on radiation damage data collected from lysozyme, glucose isomerase and xylanase, and it is found that no single metric is sufficient to describe radiation damage in SAXS for all samples. The radius of gyration, molecular weight and integrated SAXS profile intensity constitute a minimal set of parameters that capture all types of observed behavior. Radiation sensitivities derived from these parameters show a large protein dependence, varying by up to six orders of magnitude between the different proteins tested. This work should enable consistent reporting of radiation damage effects, allowing more systematic studies of the most effective minimization strategies.

  14. 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.

  15. Perspectives in radiation biophysics: From radiation track structure simulation to mechanistic models of DNA damage and repair

    Science.gov (United States)

    Nikjoo, H.; Taleei, R.; Liamsuwan, T.; Liljequist, D.; Emfietzoglou, D.

    2016-11-01

    In radiation targeted therapy and genetic risk estimation of low dose radiation protection there is a crucial need for full description of DNA damage response and repair (DDR) leading to cell death and cell mutation. We propose such a description can be arrived through realistic track-structure simulations together with mechanistic mathematical formulation of DDR and the availability of experimental data for testing the proof of principle. In this paper we review briefly first the state of the art in DNA damage and repair, and then the recent advances in the physics of track structure which represents an essential tool in radiation biophysics.

  16. Charge-trap correction and radiation damage in orthogonal-strip planar germanium detectors

    Energy Technology Data Exchange (ETDEWEB)

    Hull, E.L. [PHDS Corporation, 3011 Amherst Road, Knoxville, TN 37921 (United States); Jackson, E.G.; Lister, C.J. [Physics Department, University of Massachusetts Lowell, Lowell, MA 01854 (United States); Pehl, R.H. [PHDS Corporation, 3011 Amherst Road, Knoxville, TN 37921 (United States)

    2014-10-21

    A charge-carrier trap correction technique was developed for orthogonal strip planar germanium gamma-ray detectors. The trap corrector significantly improves the gamma-ray energy resolution of detectors with charge-carrier trapping from crystal-growth defects and radiation damage. Two orthogonal-strip planar germanium detectors were radiation damaged with 2-MeV neutron fluences of ∼8×10{sup 9} n/cm{sup 2}. The radiation-damaged detectors were studied in the 60–80 K temperature range.

  17. Mechanisms of Retinal Damage from Chronic Laser Radiation.

    Science.gov (United States)

    1981-07-01

    W.K.: The effects of the pineal gland on light-induced retinal photoreceptor damage. Exp. Eye Res. 28:37-44, 1979. 17. Hollyfield, Joe G., Rayborn...co-iI workers in 196612. Noell reported that irreversible retinal damage occurs in normal laboratory rats exposed continuously to an illuminated...light than with either red or blue light. In fact, the action spectrum of the damage paralleled the action spectrum of the ERG. The iris of pigmented rats

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

    Energy Technology Data Exchange (ETDEWEB)

    Franks, L.A.; James, R.B.

    1998-04-01

    The literature of radiation damage measurements on cadmium zinc telluride (CZT), cadmium telluride (CT), and mercuric iodide (HgI{sub 2}) 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 10{sup 10} p/cm{sup 2} and significant bulk leakage after 10{sup 12} p/cm{sup 2}. CZT exposed to 200 MeV protons shows a two-fold loss in energy resolution after a fluence of 5 {times} 10{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 moderated fission spectrum neutrons after fluences up to 10{sup 10} n/cm{sup 2}, although activation was evident. CT detectors show resolution losses after fluences of 3 {times} 10{sup 9} p/cm{sup 2} 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 {times} 10{sup 10} n/cm{sup 2}. Mercuric iodide has been studied with intermediate energy protons (10 to 33 MeV) at fluences up to 10{sup 12} p/cm{sup 2} and with 1.5 GeV protons at fluences up to 1.2 {times} 10{sup 8} p/cm{sup 2}. Neutron exposures at 8 MeV have been reported at fluences up to 10{sup 15} n/cm{sup 2}. No radiation damage was found under these irradiation conditions.

  19. Radiation Combined Injury: DNA Damage, Apoptosis, and Autophagy

    Science.gov (United States)

    2010-01-01

    the course of their disease (5) represents another significant source of exposure as normal tissues are subjected to radiation injury. Those charged...received thermal burns concurrent with radiation injury, (26, 35). At the Chernobyl reactor meltdown, 10% of 237 victims exposed to radiation received...injections, orally administered drugs, and perhaps subcutaneous injections (39) may be the most complex treatments available to mass casualty victims

  20. 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...

  1. 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 technologies...

  2. A Single-Molecule Study on the Structural Damage of Ultraviolet Radiated DNA

    Directory of Open Access Journals (Sweden)

    Pu Chun Ke

    2008-04-01

    Full Text Available The structural damage of double-stranded DNA under UV radiation was examined using single-molecule fluorescence microscopy. Compared to undamaged DNA, the diffusion coefficient of λ-DNA was significantly increased with 12 min or 20 min of radiation but remained unchanged for 40 min of exposure possibly due to strand crosslinking. The structural damage of DNA was further examined using transmission electron microscopy which revealed kinks and sharp bends along the DNA backbone.

  3. Measurements and TCAD Simulations of Bulk and Surface Radiation Damage Effects

    CERN Document Server

    F. Moscatelli; G. M. Bilei; A. Morozzi; G.-F. Dalla Betta; R. Mendicino; M. Boscardin; N. Zorzi; L. Servoli; P. Maccagnani

    2016-01-01

    In this work we propose the application of a radiation damage model based on the introduction of deep level traps/recombination centers suitable for device level numerical simulation of radiation detectors at very high fluences (e.g. 1÷2×1016 1-MeV equivalent neutrons per square centimeter) combined with a surface damage model developed by using experimental parameters extracted from measurements from gamma irradiated p-type dedicated test structures.

  4. Radiation Damage of F8 Lead Glass with 20 MeV Electrons

    CERN Document Server

    Schaefer, B D; McChesney, P; Shepherd, M R; Frye, J M

    2011-01-01

    Using a 20 MeV linear accelerator, we investigate the effects of electromagnetic radiation on the optical transparency of F8 lead glass. Specifically, we measure the change in attenuation length as a function of radiation dose. Comparing our results to similar work that utilized a proton beam, we conclude that F8 lead glass is more susceptible to proton damage than electron damage.

  5. PWO crystals for CMS electromagnetic calorimeter : studies of the radiation damage kinetics

    OpenAIRE

    Drobychev, G.; Auffray, E.; Dormenev, V.; Korzhik, M; Lecoq, P.; Lopatic, A.; Nédélec, P.; Peigneux, J. P.; D. Sillou

    2005-01-01

    Kinetics of radiation damage of the PWO crystals under irradiation and recovery were studied. Crystals were irradiated with dose corresponding to average one expected in the electromagnetic calorimeter (working dose irradiation). Radiation damage and recovery were monitored through measurements of PWO optical transmission. An approach is proposed which allows evaluating the influence of the PWO crystals properties on the statistical term in the energy resolution of the electromagnetic calorim...

  6. Radiation damage of F8 lead glass with 20 MeV electrons

    Science.gov (United States)

    Schaefer, B. D.; Mitchell, R. E.; McChesney, P.; Shepherd, M. R.; Frye, J. M.

    2012-03-01

    Using a 20 MeV linear accelerator, we investigate the effects of electromagnetic radiation on the optical transparency of F8 lead glass. Specifically, we measure the change in attenuation length as a function of radiation dose. Comparing our results to similar work that utilized a proton beam, we conclude that F8 lead glass is more susceptible to proton damage than electron damage.

  7. Measurements and TCAD Simulations of Bulk and Surface Radiation Damage Effects in Silicon Detectors

    CERN Document Server

    Moscatelli, F; Passeri, D; Bilei, G M; Servoli, L; Morozzi, A; Betta, G -F Dalla; Mendicino, R; Boscardin, M; Zorzi, N

    2016-01-01

    In this work we propose the application of a radiation damage model based on the introduction of deep level traps/recombination centers suitable for device level numerical simulation of radiation detectors at very high fluences (e.g. 1{\\div}2 10^16 1-MeV equivalent neutrons per square centimeter) combined with a surface damage model developed by using experimental parameters extracted from measurements from gamma irradiated p-type dedicated test structures.

  8. 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…

  9. Visualizing the search for radiation-damaged DNA bases in real time

    Science.gov (United States)

    Lee, Andrea J.; Wallace, Susan S.

    2016-11-01

    The Base Excision Repair (BER) pathway removes the vast majority of damages produced by ionizing radiation, including the plethora of radiation-damaged purines and pyrimidines. The first enzymes in the BER pathway are DNA glycosylases, which are responsible for finding and removing the damaged base. Although much is known about the biochemistry of DNA glycosylases, how these enzymes locate their specific damage substrates among an excess of undamaged bases has long remained a mystery. Here we describe the use of single molecule fluorescence to observe the bacterial DNA glycosylases, Nth, Fpg and Nei, scanning along undamaged and damaged DNA. We show that all three enzymes randomly diffuse on the DNA molecule and employ a wedge residue to search for and locate damage. The search behavior of the Escherichia coli DNA glycosylases likely provides a paradigm for their homologous mammalian counterparts.

  10. Simulation study of radiation damage induced by energetic helium nuclei

    CERN Document Server

    Hoang Dac Luc; Hoang Dac Dat

    2003-01-01

    High energy alpha particles produced by neutron-induced nuclear reactions can damage severely reactor materials. Simulation of this process is described using theoretical calculation and ion irradiation experiments at different displacement doses and Helium doses.

  11. The contribution of endogenous and exogenous effects to radiation-induced damage in the bacterial spore.

    Science.gov (United States)

    Jacobs, G P; Samuni, A; Czapski, G

    1985-06-01

    Radical scavengers such as polyethylene glycol 400 and 4000 and bovine albumin have been used to define the contribution of exogenous and endogenous effects to the gamma-radiation-induced damage in aqueous buffered suspensions of Bacillus pumilus spores. The results indicate that this damage in the bacterial spore is predominantly endogenous both in the presence of 1 atmosphere of oxygen, and in anoxia.

  12. Contribution of endogenous and exogenous effects to radiation-induced damage in the bacterial spore

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, G.P. (Hebrew Univ., Jerusalem (Israel). School of Pharmacy); Samuni, A. (Hebrew Univ., Jerusalem (Israel). School of Medicine); Czapski, G. (Hebrew Univ., Jerusalem (Israel). Dept. of Physical Chemistry)

    1985-06-01

    Radical scavengers such as polyethylene glycol 400 and 4000 and bovine albumin have been used to define the contribution of exogenous and endogenous effects to the gamma-radiation-induced damage in aqueous buffered suspensions of Bacillus pumilus spores. The results indicate that this damage in the bacterial spore is predominantly endogenous both in the presence of 1 atmosphere of oxygen, and in anoxia.

  13. DNA repair pathways in radiation induced cellular damage: a molecular approach

    NARCIS (Netherlands)

    L.R. van Veelen (Lieneke)

    2005-01-01

    markdownabstract__Abstract__ DNA damage, especially double-strand breaks, can be induced by endogenous or exogenous darnaging agents, such as ionizing radiation. Repair of DNA damage is very important in maintaining genomic stability. Incorrect repair may lead to chromosomal aberrations,

  14. Nanocrystal ghosting: Extensive radiation damage in MgO induced by low-energy electrons

    Science.gov (United States)

    Frankenfield, Zackery; Kane, Kenneth; Sawyer, William H.

    2017-03-01

    We report direct evidence of extensive radiation damage in MgO nanocrystals due to intense bombardment (2 × 10 electrons/nm sec) by electrons with beam energies between 60 keV and 120 keV. Based upon a minimum intensity necessary to produce the observed damage, we present an explanation based on the Knotek-Feibelman process.

  15. DNA repair pathways in radiation induced cellular damage: a molecular approach

    NARCIS (Netherlands)

    L.R. van Veelen (Lieneke)

    2005-01-01

    markdownabstract__Abstract__ DNA damage, especially double-strand breaks, can be induced by endogenous or exogenous darnaging agents, such as ionizing radiation. Repair of DNA damage is very important in maintaining genomic stability. Incorrect repair may lead to chromosomal aberrations, translocat

  16. Radiation-Induced Nano-Explosions at the Solid Surface:Near Surface Radiation Damage in CR-39 Polymer

    Institute of Scientific and Technical Information of China (English)

    Mukhtar Ahmed Rana

    2011-01-01

    @@ New measurements of fission fragment and alpha particle induced surface damage in the most sensitive and commonly used nuclear track detector CR-39 are presented here.Precisely designed and optimized exposure and chemical etching experiments are employed to unfold the structure of radiation induced surface damage (RISD).Delay in the startup of the chemical etching of latent tracks or surface radiation damage is measured and is found to contain important information about the structure of the surface damage.Simple atomic scale pictures of RISD and its chemical etching are developed in an empirical manner.Theoretical model and experimental findings coherently compose a realistic picture of early or ferntosecond evolution of RISD.

  17. Compilation of radiation damage test data part III: materials used around high-energy accelerators

    CERN Document Server

    Beynel, P; Schönbacher, H; CERN. Geneva

    1982-01-01

    For pt.II see CERN report 79-08 (1979). 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.

  18. 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.

  19. A new CT-based method to quantify radiation-induced lung damage in patients.

    Science.gov (United States)

    Ghobadi, Ghazaleh; Wiegman, Erwin M; Langendijk, Johannes A; Widder, Joachim; Coppes, Robert P; van Luijk, Peter

    2015-10-01

    A new method to assess radiation-induced lung toxicity (RILT) using CT-scans was developed. It is more sensitive in detecting damage and corresponds better to physician-rated radiation pneumonitis than routinely-used methods. Use of this method may improve lung toxicity assessment and thereby facilitate development of more accurate predictive models for RILT.

  20. DETECTION OF LOW DOSE RADIATION INDUCED DNA DAMAGE USING TEMPERATURE DIFFERENNTIAL FLUORESENCE ASSAY

    Science.gov (United States)

    A rapid and sensitive fluorescence assay for radiation-induced DNA damage is reported. Changes in temperature-induced strand separation in both calf thymus DNA and plasmid DNA (puc 19 plasmid from Escherichia coli) were measured after exposure to low doses of radiation. Exposures...

  1. DETECTION OF LOW DOSE RADIATION INDUCED DNA DAMAGE USING TEMPERATURE DIFFERENTIAL FLUORESCENCE ASSAY

    Science.gov (United States)

    A rapid and sensitive fluorescence assay for radiation-induced DNA damage is reported. Changes in temperature-induced strand separation in both calf thymus DNA and plasmid DNA (puc 19 plasmid from Escherichia coli) were measured after exposure to low doses of radiation. Exposur...

  2. Investigations in silicate glasses. I. Radiation damage. II. Optical nonlinearity. [Gamma rays and electrons

    Energy Technology Data Exchange (ETDEWEB)

    Moran, M.J.

    1976-11-15

    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, n/sub 2/, 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 n/sub 2/ of sample materials to the n/sub 2/ of CS/sub 2/. This method avoids some of the complications associated with performing absolute measurements of n/sub 2/ 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

  3. Proton irradiation of stem cells: Radiation damage and chemical radioprotection

    Science.gov (United States)

    Riley, R. C.; Montour, J. L.; Gurney, C. W.

    1972-01-01

    Effects of high energy protons on erythropoietic stem cells and radioprotection by chemicals were investigated in NASA Space Radiation Effects Laboratory. The effects of a parallel beam of 600 MeV protons. The fluence, when converted to dose, were referenced to the synchrocyclotron beam monitors which were then used to administer radiation exposures. Mice were given graded doses to 300 rads to determine dose-response curve. Other mice received saline, AET, or 5-hydroxytryptamine 10 to 15 minutes before exposure.

  4. RADIATION DAMAGE TO BSCCO-2223 FROM 50 MEV PROTONS

    Energy Technology Data Exchange (ETDEWEB)

    Zeller, A.F.; Ronningen, R.M.; Godeke, Arno; Heibronn, L.H; McMahan-Norris, P.; Gupta, R.

    2007-11-01

    The use of HTS materials in high radiation environments requires that the superconducting properties remain constant up to a radiation high dose. BSCCO-2223 samples from two manufacturers were irradiated with 50 MeV protons at fluences of up to 5 x 10{sup 17} protons/cm{sup 2}. The samples lost approximately 75% of their pre-irradiation I{sub c}. This compares with Nb{sub 3}Sn, which loses about 50% at the same displacements per atom.

  5. Inflammation and Immunity in Radiation Damage to the Gut Mucosa

    Directory of Open Access Journals (Sweden)

    Agnès François

    2013-01-01

    Full Text Available Erythema was observed on the skin of the first patients treated with radiation therapy. It is in particular to reduce this erythema, one feature of tissue inflammation, that prescribed dose to the tumor site started to be fractionated. It is now well known that radiation exposure of normal tissues generates a sustained and apparently uncontrolled inflammatory process. Radiation-induced inflammation is always observed, often described, sometimes partly explained, but still today far from being completely understood. The thing with the gut and especially the gut mucosa is that it is at the frontier between the external milieu and the organism, is in contact with a plethora of commensal and foreign antigens, possesses a dense-associated lymphoid tissue, and is particularly radiation sensitive because of a high mucosal turnover rate. All these characteristics make the gut mucosa a strong responsive organ in terms of radiation-induced immunoinflammation. This paper will focus on what has been observed in the normal gut and what remains to be done concerning the immunoinflammatory response following localized radiation exposure.

  6. Temperature dependence of radiation damage and its annealing in silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Ziock, H.J.; Boissevain, J.G.; Holzscheiter, K.; Kapustinsky, J.S.; Palounek, A.P.T.; Sondheim, W.E. [Los Alamos National Lab., NM (United States); Barberis, E.; Cartiglia, N.; Leslie, J.; Pitzl, D.; Rowe, W.A.; Sadrozinski, H.F.W.; Seiden, A.; Spencer, E.; Wilder, M. [California Univ., Santa Cruz, CA (United States). Inst. for Particle Physics; Ellison, J.A.; Fleming, J.K.; Jerger, S.; Joyce, D.; Lietzke, C.; Reed, E.; Wimpenny, S.J. [California Univ., Riverside, CA (United States); Ferguson, P. [Missouri Univ., Rolla, MO (United States); Frautschi, M.A.; Matthews, J.A.J.; Skinner, D. [New Mexico Univ., Albuquerque, NM (United States)

    1992-12-01

    The radiation damage resulting from the large particle fluences predicted at the Superconducting Super Collider will induce significant leakage currents in silicon detectors. In order to limit those currents, we plan to operate the detectors at reduced temperatures ({approximately}0{degree} C). In this paper, we present the results of a study of temperature effects on both the initial radiation damage and the long-term annealing of that damage in silicon PIN detectors. Depletion voltage results are reported. The detectors were exposed to approximately 10{sup 14}/cm{sup 2} 650 MeV protons. Very pronounced temperature dependencies were observed.

  7. Temperature dependence of radiation damage and its annealing in silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Ziock, H.J.; Boissevain, J.G.; Holzscheiter, K.; Kapustinsky, J.S.; Palounek, A.P.T.; Sondheim, W.E. (Los Alamos National Lab., NM (United States)); Barberis, E.; Cartiglia, N.; Leslie, J.; Pitzl, D.; Rowe, W.A.; Sadrozinski, H.F.W.; Seiden, A.; Spencer, E.; Wilder, M. (Univ. of California, Santa Cruz, CA (United States). Santa Cruz Inst. for Particle Physics); Ellison, J.A.; Fleming, J.K.; Jerger, S.; Joyce, D.; Lietzke, C.; Reed, E.; Wimpenny, S.J. (Univ. of California, Riverside, CA (United States)); Ferguson, P. (Univ. of Missouri, Rolla, MO (United States)); Frautschi, M.A.; Matthews, J.A.J.; Skinner, D. (Univ. of New Mexico, Albuquerque, NM (United States))

    1993-08-01

    The radiation damage resulting from the large particle fluences predicted at the Superconducting Super Collider will induce significant leakage currents in silicon detectors. In order to limit those currents, the authors plan to operate the detectors at reduced temperatures ([approximately] 0 C). In this paper, they present the results of a study of temperature effects on both the initial radiation damage and the long-term annealing of that damage in silicon PIN detectors. Depletion voltage results are reported. The detectors were exposed to approximately 10[sup 14]/cm[sup 2] 650 MeV protons. Very pronounced temperature dependencies were observed.

  8. Temperature dependence of radiation damage and its annealing in silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Ziock, H.J.; Boissevain, J.G.; Holzscheiter, K.; Kapustinsky, J.S.; Palounek, A.P.T.; Sondheim, W.E. (Los Alamos National Lab., NM (United States)); Barberis, E.; Cartiglia, N.; Leslie, J.; Pitzl, D.; Rowe, W.A.; Sadrozinski, H.F.W.; Seiden, A.; Spencer, E.; Wilder, M. (California Univ., Santa Cruz, CA (United States). Inst. for Particle Physics); Ellison, J.A.; Fleming, J.K.; Jerger, S.; Joyce, D.; Lietzke, C.; Re

    1992-01-01

    The radiation damage resulting from the large particle fluences predicted at the Superconducting Super Collider will induce significant leakage currents in silicon detectors. In order to limit those currents, we plan to operate the detectors at reduced temperatures ([approximately]0[degree] C). In this paper, we present the results of a study of temperature effects on both the initial radiation damage and the long-term annealing of that damage in silicon PIN detectors. Depletion voltage results are reported. The detectors were exposed to approximately 10[sup 14]/cm[sup 2] 650 MeV protons. Very pronounced temperature dependencies were observed.

  9. The radiation damage of crystalline silicon PN diode in tritium beta-voltaic battery.

    Science.gov (United States)

    Lei, Yisong; Yang, Yuqing; Liu, Yebing; Li, Hao; Wang, Guanquan; Hu, Rui; Xiong, Xiaoling; Luo, Shunzhong

    2014-08-01

    A tritium beta-voltaic battery using a crystalline silicon convertor composed of (100)Si/SiO2/Si3N4 film degrades remarkably with radiation from a high intensity titanium tritide film. Simulation and experiments were carried out to investigate the main factor causing the degradation. The radiation damages mainly comes from the x-ray emitted from the titanium tritide film and beta particle can relieve the damages. The x-ray radiation induced positive charges in the SiO2 film destroying the output property of the PN diode with the induction of an electric field.

  10. Radiation damage in plastic detectors; Dano por radiacion en detectores plasticos

    Energy Technology Data Exchange (ETDEWEB)

    Balcazar, M. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Tavera, L. [UAEM, Facultad de Quimica, 50000 Toluca, Estado de Mexico (Mexico)

    2007-07-01

    Full text: The damage induced by ionizing radiation in plastics produce a wide diversity of changes in the either the whole polymer structure or a localized high destruction. The first effect is achieved by using gamma and/or electron irradiation, whereas the second is carry out by employing positive ions irradiation. The damage intensity can be controlled by the dose delivery to the plastic, in the first case and by the rate of energy loss of the incident ion in the second case. Damage deepness in the thickness of the plastic, depends of radiation energy, although, attenuation effects have to be considered for gamma and electron irradiation. This paper presents an overview of those effects, the applications for radiation dosimetry and the production of micro and nano pores, as well as the methodology for control all parameters involved in the damage. Techniques for visualization the localized high destruction in the plastics are also presented. (Author)

  11. Radiation tolerance of ceramics—Insights from atomistic simulation of damage accumulation in pyrochlores

    Energy Technology Data Exchange (ETDEWEB)

    Devanathan, Ramaswami; Weber, William J.; Gale, Julian D.

    2010-10-01

    We have used molecular dynamics simulations to examine the effects of radiation damage accumulation in two pyrochlore-structured ceramics, namely Gd2Ti2O7 and Gd2Zr2O7. It is well known from experiment that the titanate is susceptible to radiation-induced amorphization, while the zirconate does not go amorphous under prolonged irradiation. Our simulations show that cation Frenkel pair accumulation eventually leads to amorphization of Gd2Ti2O7. Anion disorder occurs with cation disorder. The amorphization is accompanied by a density decrease of about 12.7% and a decrease of about 50% in the elastic modulus. In Gd2Zr2O7, amorphization does not occur, because the residual damage is not sufficiently energetic to drive the material amorphous. Subtle differences in damage accumulation and annealing between the two pyrochlores lead to drastically different radiation response as the damage accumulates.

  12. Modeling high-energy radiation damage in nuclear and fusion applications

    Energy Technology Data Exchange (ETDEWEB)

    Trachenko, K., E-mail: k.trachenko@qmul.ac.uk [School of Physics, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); School of Physics and Astronomy, University of Southampton Highfield, Southampton SO17 1BJ (United Kingdom); Zarkadoula, E. [School of Physics, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); School of Physics and Astronomy, University of Southampton Highfield, Southampton SO17 1BJ (United Kingdom); Todorov, I.T. [Computational Science and Engineering Department, CCLRC Daresbury Laboratory, Daresbury WA44AD (United Kingdom); Dove, M.T. [School of Physics, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ (United Kingdom); Dunstan, D.J. [School of Physics, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Nordlund, K. [Accelerator Laboratory, University of Helsinki, P.O. Box 43, FIN-00014 Helsinki (Finland)

    2012-04-15

    We discuss molecular dynamics (MD) simulations of high-energy radiation damage in materials relevant for encapsulation of nuclear waste and materials to be used in fusion reactors, including several important oxides and iron. We study various stages of evolution and relaxation of 100-200 keV collision cascades, and identify reversible elastic and irreversible inelastic structural changes. The elastic expansion of the lattice around the cascade is explained in terms of anharmonicity of interatomic interactions. The remaining irreversible structural change is related to resistance to amorphization by radiation damage. This resistance is quantified by the number of remaining defect atoms in the damaged structure. We discuss how MD simulations can predict experimental resistance to amorphization, including the important case of highly resistant materials. Finally, we discuss our current work to simulate radiation damage of MeV energies and system sizes of the order of billion atoms using massive parallel computing facilities.

  13. 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.

  14. 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.

  15. 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.

  16. Ionizing radiation, antioxidant response and oxidative damage: A meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Einor, D., E-mail: daniel@einor.com [Department of Biological Sciences, University of South Carolina, Columbia, SC 29208 (United States); Bonisoli-Alquati, A., E-mail: andreabonisoli@gmail.com [Department of Biological Sciences, University of South Carolina, Columbia, SC 29208 (United States); School of Renewable Natural Resources, Louisiana State University AgCenter, Baton Rouge, LA 70803 (United States); Costantini, D., E-mail: davidcostantini@libero.it [Department of Biology, University of Antwerp, Wilrijk, B-2610, Antwerp (Belgium); Mousseau, T.A., E-mail: mousseau@sc.edu [Department of Biological Sciences, University of South Carolina, Columbia, SC 29208 (United States); Faculty of Bioscience and Biotechnology, Chubu University, Kasugai (Japan); Møller, A.P., E-mail: anders.moller@u-psud.fr [Laboratoire d' Ecologie, Systématique et Evolution, CNRS UMR 8079, Université Paris-Sud, Bâtiment 362, F-91405 Orsay Cedex (France)

    2016-04-01

    One mechanism proposed as a link between exposure to ionizing radiation and detrimental effects on organisms is oxidative damage. To test this hypothesis, we surveyed the scientific literature on the effects of chronic low-dose ionizing radiation (LDIR) on antioxidant responses and oxidative damage. We found 40 publications and 212 effect sizes for antioxidant responses and 288 effect sizes for effects of oxidative damage. We performed a meta-analysis of signed and unsigned effect sizes. We found large unsigned effects for both categories (0.918 for oxidative damage; 0.973 for antioxidant response). Mean signed effect size weighted by sample size was 0.276 for oxidative damage and − 0.350 for antioxidant defenses, with significant heterogeneity among effects for both categories, implying that ionizing radiation caused small to intermediate increases in oxidative damage and small to intermediate decreases in antioxidant defenses. Our estimates are robust, as shown by very high fail-safe numbers. Species, biological matrix (tissue, blood, sperm) and age predicted the magnitude of effects for oxidative damage as well as antioxidant response. Meta-regression models showed that effect sizes for oxidative damage varied among species and age classes, while effect sizes for antioxidant responses varied among species and biological matrices. Our results are consistent with the description of mechanisms underlying pathological effects of chronic exposure to LDIR. Our results also highlight the importance of resistance to oxidative stress as one possible mechanism associated with variation in species responses to LDIR-contaminated areas. - Highlights: • There is interest in variation in metabolic effects of chronic low-dose ionizing radiation • A random effect meta-analysis of effect sizes of radioactive contamination was performed • We found significant effects of radiation on oxidative damage and antioxidant response • We found significant heterogeneity among

  17. Experimental studies of radiation damage of silicon detectors. Internal report

    Energy Technology Data Exchange (ETDEWEB)

    Angelescu, T.; Ghete, V.M.; Ghiordanescu, N.; Lazanu, I.; Mihul, A. [Univ. of Bucharest (Romania); Golutvin, I.; Lazanu, S.; Savin, I.; Vasilescu, A. [JINR, Dubna (Russian Federation); Biggeri, U.; Borchi, E.; Bruzzi, M. [Univ. of Florence (Italy)]|[INFN, Florence (Italy); Li, Z.; Kraner, H.W. [Brookhaven National Lab., Upton, NY (United States)

    1994-02-01

    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.

  18. NASA's high efficiency and radiation damage solar cell program

    Science.gov (United States)

    Randolph, L. P.

    1980-01-01

    The conversion efficiency and the life expectancy of solar cells and arrays were evaluated for space applications. Efforts were made to improve the understanding of the conversion of electromagnetic radiation to useful forms of energy. A broad range of advanced concepts were evaluated.

  19. Protective effects of melatonin on the ionizing radiation induced DNA damage in the rat brain.

    Science.gov (United States)

    Undeger, Ulko; Giray, Belma; Zorlu, A Faruk; Oge, Kamil; Baçaran, Nurçen

    2004-03-01

    Melatonin is an endogenously produced antioxidant with radioprotective actions while ionizing radiation is a well-known cytotoxic and mutagenic agent of which the biological results are attributable to its free radical producing effects. The effect of melatonin on the DNA strand breakage and lipid peroxidation induced by ionizing radiation in the rat brain were investigated in order to clarify its radioprotective ability. The DNA strand breakage in rat brain exposed to 1000 cGy ionizing radiation was assessed by alkaline single cell gel electrophoresis and the lipid peroxidation was evaluated by measuring thiobarbituric acid reactive substances (TBARS) concentrations. A significant increase in DNA damage (p radiation treated rat brain. Pre-treatment of rats with intraperitoneal doses of 100 mg/kg melatonin provided a significant decrease in the DNA strand breakage and lipid peroxidation. Our results indicate that melatonin can protect brain cells from oxidative damage induced by ionizing radiation.

  20. 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...

  1. Sunlight exposure assessment: can we accurately assess vitamin D exposure from sunlight questionnaires?

    Science.gov (United States)

    McCarty, Catherine A

    2008-04-01

    The purpose of this review is to summarize the peer-reviewed literature in relation to sunlight exposure assessment and the validity of using sunlight exposure questionnaires to quantify vitamin D status. There is greater variability in personal ultraviolet (UV) light exposure as the result of personal behavior than as the result of ambient UV light exposure. Although statistically significant, the correlation coefficients for the relation between personal report of sun exposure and ambient UV light measured by dosimetry (assessment of radiation dose) are relatively low. Moreover, the few studies to assess the relation between sunlight measures and serum 25-hydroxyvitamin D show low correlations. These low correlations may not be surprising given that personal factors like melanin content in skin and age also influence cutaneous synthesis of vitamin D. In summary, sunlight exposure questionnaires currently provide imprecise estimates of vitamin D status. Research should be directed to develop more objective, nonintrusive, and economical measures of sunlight exposure to quantify personal vitamin D status.

  2. Analyses of the secondary particle radiation and the DNA damage it causes to human keratinocytes

    Energy Technology Data Exchange (ETDEWEB)

    Lebel E.; Rusek A.; Sivertz, M.; Yip, K.; Thompson, K.; Tafrov, S.

    2011-11-22

    High-energy protons, and high mass and energy ions, along with the secondary particles they produce, are the main contributors to the radiation hazard during space explorations. Skin, particularly the epidermis, consisting mainly of keratinocytes with potential for proliferation and malignant transformation, absorbs the majority of the radiation dose. Therefore, we used normal human keratinocytes to investigate and quantify the DNA damage caused by secondary radiation. Its manifestation depends on the presence of retinol in the serum-free media, and is regulated by phosphatidylinositol 3-kinases. We simulated the generation of secondary radiation after the impact of protons and iron ions on an aluminum shield. We also measured the intensity and the type of the resulting secondary particles at two sample locations; our findings agreed well with our predictions. We showed that secondary particles inflict DNA damage to different extents, depending on the type of primary radiation. Low-energy protons produce fewer secondary particles and cause less DNA damage than do high-energy protons. However, both generate fewer secondary particles and inflict less DNA damage than do high mass and energy ions. The majority of cells repaired the initial damage, as denoted by the presence of 53BPI foci, within the first 24 hours after exposure, but some cells maintained the 53BP1 foci longer.

  3. Analyses of the Secondary Particle Radiation and the DNA Damage it Causes to Human Keratinocytes

    Energy Technology Data Exchange (ETDEWEB)

    Lebel E. A.; Tafrov S.; Rusek, A.; Sivertz, M. B.; Yip, K.; Thompson, K. H.

    2011-11-01

    High-energy protons, and high mass and energy ions, along with the secondary particles they produce, are the main contributors to the radiation hazard during space explorations. Skin, particularly the epidermis, consisting mainly of keratinocytes with potential for proliferation and malignant transformation, absorbs the majority of the radiation dose. Therefore, we used normal human keratinocytes to investigate and quantify the DNA damage caused by secondary radiation. Its manifestation depends on the presence of retinol in the serum-free media, and is regulated by phosphatidylinositol 3-kinases. We simulated the generation of secondary radiation after the impact of protons and iron ions on an aluminum shield. We also measured the intensity and the type of the resulting secondary particles at two sample locations; our findings agreed well with our predictions. We showed that secondary particles inflict DNA damage to different extents, depending on the type of primary radiation. Low-energy protons produce fewer secondary particles and cause less DNA damage than do high-energy protons. However, both generate fewer secondary particles and inflict less DNA damage than do high mass and energy ions. The majority of cells repaired the initial damage, as denoted by the presence of 53BPI foci, within the first 24 hours after exposure, but some cells maintained the 53BP1 foci longer.

  4. Mechanisms for radiation damage in DNA. Final report, June 1, 1986--August 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Sevilla, M.D.

    1996-08-01

    Over the last 10 years significant advances have been made impacting the understanding of radiation damage to DNA. The principal objective of this work was the elucidation of the fundamental mechanisms of radiation damage to DNA through the direct and indirect effects. Recently the work concentrated on the direct effect of radiation damage on DNA. The objective was to elucidate the ultimate radiation chemical damage to DNA arising from the direct effect. In this effort the focus was on the application of three techniques. ESR spectroscopic measurement of initial radicals formed in DNA and its hydration layer at low temperatures. Ab initio molecular orbital calculations were employed to give highly accurate theoretical predictions of early events such as electron and hole localization sites which serve to test and to clarify the experimental observations. HPLC and GC-mass spectroscopic assays of DNA base products formation provide the ultimate chemical outcome of the initial radiation events. The bridge between the early ion radical species and the non-radical products is made in ESR studies which follow the chemistry of the early species as they react with water and or other DNA bases. The use of these techniques has resulted in a new and fundamental understanding of the radiation damage to DNA on a molecular scale. From this work, a working model for DNA damage from the initial ionization event to the eventual formation of molecular base damage products and strand breaks has been formulated. Results over the past several years which have led to the formulation of this model are described.

  5. 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.

  6. 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

  7. Radiation damage in flexible TFTs and organic detectors

    OpenAIRE

    Almeida, Maria Teresa Gonçalves Lobato de

    2015-01-01

    In this thesis was investigated the radiation hardness of the building blocks of a future flexible X-ray sensor system. The characterized building blocks for the pixel addressing and signal amplification electronics are high mobility semiconducting oxide transistors (HMSO-TFTs) and organic transistors (OTFTs), whereas the photonic detection system is based on organic semiconducting single crystals (OSSCs). TFT parameters such as mobility, threshold voltage and subthreshold slope were measured...

  8. RADIATION DAMAGE TO BSCCO-2223 FROM 50 MEV PROTONS

    Energy Technology Data Exchange (ETDEWEB)

    Zeller, A.F.; Ronningen, R.M.; Godeke, A.; Heilbronn, L.H.; McMahan-Norris, P.; Gupta, R.

    2007-11-27

    The use of HTS materials in high radiation environmentsrequires that the superconducting properties remain constant up to aradiation high dose. BSCCO-2223 samples from two manufacturers wereirradiated with 50 MeV protons at fluences of up to 5 x 1017 protons/cm2.The samples lost approximately 75 percent of their pre-irradiation Ic.This compares with Nb3Sn, which loses about 50 percent at the samedisplacements per atom.

  9. Critical Need for Radiation Damage Tools for Space Missions

    Science.gov (United States)

    Tripathi, Ram

    2005-04-01

    NASA has a new vision for space exploration in the 21st Century encompassing a broad range of human and robotic missions including missions to Moon, Mars and beyond. As a result, there is a focus on long duration space missions. NASA, as much as ever, is committed to the safety of the missions and the crew. Exposure from the hazards of severe space radiation in deep space long duration missions is `the show stopper.' Thus, protection from the hazards of severe space radiation is of paramount importance for the new vision. There is an overwhelming emphasis on the reliability issues for the mission and the habitat. Accurate risk assessments critically depend on the accuracy of the input information about the interaction of ions with materials, electronics and tissues. A huge amount of essential experimental information for all the ions in space, across the periodic table, for a wide range of energies of several (up to a Trillion) orders of magnitude are needed for the radiation protection engineering for space missions that is simply not available (due to the high costs) and probably never will be. Therefore, there is a compelling need to develop reliable accurate models of nuclear reactions and structures that form the basic input ingredients. State-of-the-art nuclear cross sections models have been developed at the NASA Langley Research Center, however a considerable number of tools need to be developed to alleviate the situation. The vital role and importance of nuclear physics for space missions will be discussed.

  10. From DNA radiation damage to cell death: theoretical approaches.

    Science.gov (United States)

    Ballarini, Francesca

    2010-10-05

    Some representative models of radiation-induced cell death, which is a crucial endpoint in radiobiology, were reviewed. The basic assumptions were identified, their consequences on predicted cell survival were analyzed, and the advantages and drawbacks of each approach were outlined. In addition to "historical" approaches such as the Target Theory, the Linear-Quadratic model, the Theory of Dual Radiation Action and Katz' model, the more recent Local Effect Model was discussed, focusing on its application in Carbon-ion hadrontherapy. Furthermore, a mechanistic model developed at the University of Pavia and based on the relationship between cell inactivation and chromosome aberrations was presented, together with recent results; the good agreement between model predictions and literature experimental data on different radiation types (photons, protons, alpha particles, and Carbon ions) supported the idea that asymmetric chromosome aberrations like dicentrics and rings play a fundamental role for cell death. Basing on these results, a reinterpretation of the TDRA was also proposed, identifying the TDRA "sublesions" and "lesions" as clustered DNA double-strand breaks and (lethal) chromosome aberrations, respectively.

  11. From DNA Radiation Damage to Cell Death: Theoretical Approaches

    Directory of Open Access Journals (Sweden)

    Francesca Ballarini

    2010-01-01

    Full Text Available Some representative models of radiation-induced cell death, which is a crucial endpoint in radiobiology, were reviewed. The basic assumptions were identified, their consequences on predicted cell survival were analyzed, and the advantages and drawbacks of each approach were outlined. In addition to “historical” approaches such as the Target Theory, the Linear-Quadratic model, the Theory of Dual Radiation Action and Katz' model, the more recent Local Effect Model was discussed, focusing on its application in Carbon-ion hadrontherapy. Furthermore, a mechanistic model developed at the University of Pavia and based on the relationship between cell inactivation and chromosome aberrations was presented, together with recent results; the good agreement between model predictions and literature experimental data on different radiation types (photons, protons, alpha particles, and Carbon ions supported the idea that asymmetric chromosome aberrations like dicentrics and rings play a fundamental role for cell death. Basing on these results, a reinterpretation of the TDRA was also proposed, identifying the TDRA “sublesions” and “lesions” as clustered DNA double-strand breaks and (lethal chromosome aberrations, respectively.

  12. DIETARY FLAXSEED PREVENTS RADIATION-INDUCED OXIDATIVE LUNG DAMAGE, INFLAMMATION AND FIBROSIS IN A MOUSE MODEL OF THORACIC RADIATION INJURY

    Science.gov (United States)

    Lee, James C.; Krochak, Ryan; Blouin, Aaron; Kanterakis, Stathis; Chatterjee, Shampa; Arguiri, Evguenia; Vachani, Anil; Solomides, Charalambos C.; Cengel, Keith A.; Christofidou-Solomidou, Melpo

    2009-01-01

    Flaxseed (FS) has high contents of omega-3 fatty acids and lignans with antioxidant properties. Its use in preventing thoracic X-ray radiation therapy (XRT)-induced pneumonopathy has never been evaluated. We evaluated FS supplementation given to mice given before and post-XRT. FS-derived lignans, known for their direct antioxidant properties, were evaluated in abrogating ROS generation in cultured endothelial cells following gamma radiation exposure. Mice were fed 10% FS or isocaloric control diet for three weeks and given 13.5 Gy thoracic XRT. Lungs were evaluated at 24 hours for markers of radiation-induced injury, three weeks for acute lung damage (lipid peroxidation, lung edema and inflammation), and at four months for late lung damage (inflammation and fibrosis). FS-Lignans blunted ROS generation in vitro, resulting from radiation in a dose-dependent manner. FS-fed mice had reduced expression of lung injury biomarkers (Bax, p21, and TGF-beta1) at 24 hours following XRT and reduced oxidative lung damage as measured by malondialdehyde (MDA) levels at 3 weeks following XRT. In addition, FS-fed mice had decreased lung fibrosis as determined by hydroxyproline content and decreased inflammatory cell influx into lungs at 4 months post XRT. Importantly, when Lewis Lung carcinoma cells were injected systemically in mice, FS dietary supplementation did not appear to protect lung tumors from responding to thoracic XRT. Dietary FS is protective against pulmonary fibrosis, inflammation and oxidative lung damage in a murine model. Moreover, in this model, tumor radioprotection was not observed. FS lignans exhibited potent radiation-induced ROS scavenging action. Taken together, these data suggest that dietary flaxseed may be clinically useful as an agent to increase the therapeutic index of thoracic XRT by increasing the radiation tolerance of lung tissues. PMID:18981722

  13. Dependence of Radiation Damage in Stainless Steel on Irradiation Dose

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The accelerator driven radioactive clean nuclear power system (ADS) is a novel innovative idea forthe sustainable development of nuclear power system. The spallation neutron source system is one of thethree key parts of ADS, which provides source neutrons of about 1018 s-1 for the burning-up of fuels.Stainless steel (SS) is used for the beam window and target materials of the spallation neutron sourcesystem. It is irradiated by high-energy and intense protons and/or neutrons during operation. Theaccumulated displacement damage dose could reach a couple of hundred dpa (displacement per atom) per

  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. Radiation damage of graphite in fission and fusion reactor systems

    Energy Technology Data Exchange (ETDEWEB)

    Engle, G.B. (GA Technologies, Inc., San Diego, CA (USA)); Kelly, B.T. (Springfields Nuclear Power Development Labs. (UK))

    1984-05-01

    Increasing the crystalline perfection of artificial graphites is suggested as one method of reducing the crystallite damage. The life expectance for the isotropic conventional graphites will in each case depend on the reactor component for which it will be used and on its design considerations. Based on neutron damage and related dimensional changes it is estimated graphite will be tenable to about 3x10/sup 22/ n/cm/sup 2/ (EDN) at 400/sup 0/C, 0.6x10/sup 22/ n/cm/sup 2/ (EDN) at 1000/sup 0/C and 1.4x10/sup 22/ n/cm/sup 2/ (EDN) at 1400/sup 0/C. There are no data above 1400/sup 0/C on which to speculate. A dose of 2x10/sup 22/ n/cm/sup 2/ may be accumulated in times ranging from as short as a few months in the first wall region of high power density designs to the fusion plant lifetime (30 years) in the neutron reflector region behind the blanket.

  16. Radiation Damage in Silicon Detectors Caused by Hadronic and Electromagnetic Irradiation

    CERN Document Server

    Fretwurst, E.; Stahl, J.; Pintilie, I.

    2002-01-01

    The report contains various aspects of radiation damage in silicon detectors subjected to high intensity hadron and electromagnetic irradiation. It focuses on improvements for the foreseen LHC applications, employing oxygenation of silicon wafers during detector processing (result from CERN-RD48). An updated survey on hadron induced damage is given in the first article. Several improvements are outlined especially with respect to antiannealing problems associated with detector storage during LHC maintenance periods. Open questions are outlined in the final section, among which are a full understanding of differences found between proton and neutron induced damage, process related effects changing the radiation tolerance in addition to the oxygen content and the lack of understanding the changed detector properties on the basis of damage induced point and cluster defects. In addition to float zone silicon, so far entirely used for detector fabrication,Czochralski silicon was also studied and first promising re...

  17. Radiation Damage of Polypropylene Fiber Targets in Storage Rings

    CERN Document Server

    Rohdjess, H; Bisplinghoff, J; Bollmann, R; Büsser, K; Diehl, O; Dohrmann, F; Engelhardt, H P; Eversheim, P D; Greiff, J; Gross, A; Gross-Hardt, R; Hinterberger, F; Igelbrink, M; Langkau, R; Maier, R; Mosel, F; Müller, M; Muenstermann, M; Prasuhn, D; Von Rossen, P; Scheid, H; Schirm, N; Schwandt, F; Scobel, W; Trelle, H J; Wellinghausen, A; Wiedmann, W; Woller, K; Ziegler, R

    2004-01-01

    Thin polypropylene (CH$_2$) fibers have been used for internal experiments in storage rings as an option for hydrogen targets. The change of the hydrogen content due to the radiation dose applied by the circulating proton beam has been investigated in the range $1\\cdot10^6$ to $2\\cdot10^8$~Gy at beam momenta of 1.5 to 3 GeV/c by comparing the elastic pp-scattering yield to that from inelastic p-carbon reactions. It is found that the loss of hydrogen as a function of applied dose receives contributions from a fast and a slow component.

  18. Ultraviolet Radiation, Aging and the Skin: Prevention of Damage by Topical cAMP Manipulation

    OpenAIRE

    Alexandra Amaro-Ortiz; Betty Yan; John A. D'Orazio

    2014-01-01

    Being the largest and most visible organ of the body and heavily influenced by environmental factors, skin is ideal to study the long-term effects of aging. Throughout our lifetime, we accumulate damage generated by UV radiation. UV causes inflammation, immune changes, physical changes, impaired wound healing and DNA damage that promotes cellular senescence and carcinogenesis. Melanoma is the deadliest form of skin cancer and among the malignancies of highest increasing incidence over the las...

  19. 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

  20. Sestrin2 protects the myocardium against radiation-induced damage

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Yue-Can; Chi, Feng; Xing, Rui; Gao, Song; Chen, Jia-Jia; Duan, Qiong-Yu; Sun, Yu-Nan; Niu, Nan; Tang, Mei-Yue; Wu, Rong [Shengjing Hospital of China Medical University, Department of Medical Oncology, Cancer Center, Shenyang (China); Zeng, Jing [University of Washington School of Medicine, Department of Radiation Oncology, Seattle, WA (United States); Wang, Hong-Mei [Nanfang Hospital of Southern Medical University, Department of Radiation Oncology, Guangzhou (China)

    2016-05-15

    The purpose of this study was to investigate the role of Sestrin2 in response to radiation-induced injury to the heart and on the cardiomyopathy development in the mouse. Mice with genetic deletion of the Sestrin2 (Sestrin2 knockout mice [Sestrin2 KO]) and treatment with irradiation (22 or 15 Gy) were used as independent approaches to determine the role of Sestrin2. Echocardiography (before and after isoproterenol challenge) and left ventricular (LV) catheterization were performed to evaluate changes in LV dimensions and function. Masson's trichrome was used to assess myocardial fibrosis. Immunohistochemistry and Western blot were used to detect the capillary density. After 22 or 15 Gy irradiation, the LV ejection fraction (EF) was impaired in wt mice at 1 week and 4 months after irradiation when compared with sham irradiation. Compared to wt mice, Sestrin2 KO mice had significant reduction in reduced LVEF at 1 week and 4 months after irradiation. A significant increase in LV end-diastolic pressure and myocardial fibrosis and a significant decrease in capillary density were observed in irradiation-wt mice, as well as in irradiation-Sestrin2 KO mice. Sestrin2 involved in the regulation of cardiomyopathy (such as myocardial fibrosis) after irradiation. Overexpression of Sestrin2 might be useful in limiting radiation-induced myocardial injury. (orig.)

  1. Modeling of secondary radiation damage in LIGA PMMA resist exposure

    Science.gov (United States)

    Ting, Aili

    2003-01-01

    Secondary radiation during LIGA PMMA resist exposure adversely affects feature definition, sidewall taper and overall sidewall offset. Additionally, it can degrade the resist adjacent to the substrate, leading to the loss of free-standing features through undercutting during resist development or through mechanical failure of the degraded material. The source of this radiation includes photoelectrons, Auger electrons, fluorescence photons, etc. Sandia"s Integrated Tiger Series (ITS), a coupled electron/photon Monte Carlo transport code, was used to compute dose profiles within 1 to 2 microns of the absorber edge and near the interface of the resist with a metallized substrate. The difficulty of sub-micron resolution requirement was overcome by solving a few local problems having carefully designed micron-scale geometries. The results indicate a 2-μm dose transition region near the absorber edge resulting from PMMA"s photoelectrons. This region leads to sidewall offset and to tapered sidewalls following resist development. The results also show a dose boundary layer of around 1 μm near the substrate interface due to electrons emitted from the substrate metallization layer. The maximum dose at the resist bottom under the absorber can be very high and can lead to feature loss during development. This model was also used to investigate those resist doses resulting from multi-layer substrate.

  2. Comparison of radiation damage in silicon induced by proton and neutron irradiation

    CERN Document Server

    Ruzin, A; Glaser, M; Zanet, A; Lemeilleur, F; Watts, S

    1999-01-01

    The subject of radiation damage to Si detectors induced by 24-GeV/c protons and nuclear reactor neutrons has been studied. Detectors fabricated on single-crystal silicon enriched with various impurities have been tested. Significant differences in electrically active defects have been found between the various types of material. The results of the study suggest for the first time that the widely used nonionizing energy loss (NIEL) factors are insufficient for normalization of the electrically active damage in case of oxygen- and carbon-enriched silicon detectors. It has been found that a deliberate introduction of impurities into the semiconductor can affect the radiation hardness of silicon detectors. (16 refs).

  3. 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.

  4. Exposure to 1800 MHz radiofrequency radiation induces oxidative damage to mitochondrial DNA in primary cultured neurons.

    Science.gov (United States)

    Xu, Shangcheng; Zhou, Zhou; Zhang, Lei; Yu, Zhengping; Zhang, Wei; Wang, Yuan; Wang, Xubu; Li, Maoquan; Chen, Yang; Chen, Chunhai; He, Mindi; Zhang, Guangbin; Zhong, Min

    2010-01-22

    Increasing evidence indicates that oxidative stress may be involved in the adverse effects of radiofrequency (RF) radiation on the brain. Because mitochondrial DNA (mtDNA) defects are closely associated with various nervous system diseases and mtDNA is particularly susceptible to oxidative stress, the purpose of this study was to determine whether radiofrequency radiation can cause oxidative damage to mtDNA. In this study, we exposed primary cultured cortical neurons to pulsed RF electromagnetic fields at a frequency of 1800 MHz modulated by 217 Hz at an average special absorption rate (SAR) of 2 W/kg. At 24 h after exposure, we found that RF radiation induced a significant increase in the levels of 8-hydroxyguanine (8-OHdG), a common biomarker of DNA oxidative damage, in the mitochondria of neurons. Concomitant with this finding, the copy number of mtDNA and the levels of mitochondrial RNA (mtRNA) transcripts showed an obvious reduction after RF exposure. Each of these mtDNA disturbances could be reversed by pretreatment with melatonin, which is known to be an efficient antioxidant in the brain. Together, these results suggested that 1800 MHz RF radiation could cause oxidative damage to mtDNA in primary cultured neurons. Oxidative damage to mtDNA may account for the neurotoxicity of RF radiation in the brain.

  5. Delayed repair of radiation induced clustered DNA damage: Friend or foe?

    Energy Technology Data Exchange (ETDEWEB)

    Eccles, Laura J., E-mail: laura.eccles@rob.ox.ac.uk [DNA Damage Group, Gray Institute for Radiation Oncology and Biology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ (United Kingdom); O' Neill, Peter, E-mail: peter.oneill@rob.ox.ac.uk [DNA Damage Group, Gray Institute for Radiation Oncology and Biology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ (United Kingdom); Lomax, Martine E., E-mail: martine.lomax@rob.ox.ac.uk [DNA Damage Group, Gray Institute for Radiation Oncology and Biology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ (United Kingdom)

    2011-06-03

    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.

  6. Neutron radiation damage and recovery studies of SiPMs

    Energy Technology Data Exchange (ETDEWEB)

    Tsang, T.; Rao, T.; Stoll, S.; Woody, C.

    2016-12-01

    We characterized the performance of Silicon Photomultipliers (SiPMs) before and after exposure of up to 1012 neutron/cm2 dosage. We show that the typical orders of magnitude increase of dark current upon neutron irradiation can be suppressed by operating it at a lower temperature and single-photoelectron detection capability can be restored. The required operating temperature depends on the dosage received. Furthermore, after high temperature thermal annealing, there is compelling evidence that the extrinsic dark current is lowered by orders of magnitude and single-photon detection performance are to some extent recovered at room temperature. Our experimental findings might have widespread implications for extending the functionality and the useful lifetime of current and future large scale SiPM detectors deployed in ionization radiation environment.

  7. Neutron radiation damage and recovery studies of SiPMs

    Science.gov (United States)

    Tsang, T.; Rao, T.; Stoll, S.; Woody, C.

    2016-12-01

    We characterized the performance of Silicon Photomultipliers (SiPMs) before and after exposure of up to 1012 neutron/cm2 dosage. We show that the typical orders of magnitude increase of dark current upon neutron irradiation can be suppressed by operating it at a lower temperature and single-photoelectron detection capability can be restored. The required operating temperature depends on the dosage received. Furthermore, after high temperature thermal annealing, there is compelling evidence that the extrinsic dark current is lowered by orders of magnitude and single-photon detection performance are to some extent recovered at room temperature. Our experimental findings might have widespread implications for extending the functionality and the useful lifetime of current and future large scale SiPM detectors deployed in ionization radiation environment.

  8. Radiation damage study using small-angle neutron scattering

    Science.gov (United States)

    Rétfalvi, E.; Török, Gy; Rosta, L.

    2000-03-01

    Nuclear radiation provides important changes in the microstructure of metallic components of nuclear power plant and research reactors, influencing their mechanical properties. The investigation of this problem has primary interest for the safety and life-time of such nuclear installations. For the characterization of this kind of nanostructures small angle neutron scattering technique is a very useful tool. We have carried out experiments on samples of irradiated reactor vessel material and welded components of VVER-440-type reactors on the SANS instrument at the Budapest Research Reactor. In our measurements irradiated as well as non-irradiated samples were compared and magnetic field was applied for viewing the magnetic structure effects of the materials. A clear modification of the structure due to irradiation was obtained. Our data were analyzed by the ITP92 code, the inverse Fourier transform program of O. Glatter [1].

  9. Radiation damage in negative-differential resistance devices

    Energy Technology Data Exchange (ETDEWEB)

    Soliman, F.A.S. (Nuclear Materials Authority, Cairo (Egypt)); Kamh, S.A. (Ain-Shams Univ., Cairo (Egypt). Faculty of Women for Arts, Science and Education)

    1994-02-01

    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 10[sup 14]-10[sup 18] n cm[sup -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 [mu]A to 30 [mu]A 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 10[sup 16] n cm[sup -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 10[sup 18] n cm[sup -2] or to gamma doses up to 2.6 x 10[sup 8] rad, were greatly influenced and they lost their main feature as PN-junctions. (Author).

  10. Alterations in phosphate metabolism during cellular recovery of radiation damage in yeast

    Energy Technology Data Exchange (ETDEWEB)

    Holahan, P.K.; Knizner, S.A.; Gabriel, C.M.; Swenberg, C.E.

    1988-01-01

    Alterations were examined in phosphate pools during cellular recovery from radiation damage in intact, wild-type diploid yeast cells using phosphorus 31 nuclear magnetic resonance (NMR) spectroscopy. Concurrent cell survival analysis was determined following exposure to cobalt 60 gamma radiation. Cells held in citrate-buffered saline (CBS) showed increased survival with increasing time after irradiation (liquid holding recovery, LHR) with no further recovery beyond 48 h. Addition of 100 mmol/cu. dm glucose to the recovery medium resulted in greater recovery. In the presence of 5 mmol/cu. dm 2-deoxyglucose (2-DG), LHR was completely inhibited. ATP was observable by NMR only when glucose was present in the recovery medium. In control cells, ATP concentrations increased and plateaued with increasing recovery time. With increasing radiation dose, the increase in ATP was of lesser magnitude, and after 2000 Gy no increase was observed. The observations suggest that either the production of ATP in irradiated cells is suppressed, or there is enhanced ATP utilization for repair of radiation damage. In CBS with 100 mmol/cu. dm glucose, a dose-dependent decrease in polyphosphate (polyP) was detectable with no concurrent increase in inorganic phosphate (p sub i). When 2-DG was present in the recovery medium, polyP decreased, but there was a simultaneous increase in p sub i with increasing radiation dose and recovery time. This suggests that the polyP are hydrolyzed as a source of phosphates for repair of radiation damage.

  11. 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.

  12. 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.

  13. 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.).

  14. Hair cortisol and cortisone are decreased by natural sunlight.

    Science.gov (United States)

    Wester, Vincent L; van der Wulp, Nils R P; Koper, Jan W; de Rijke, Yolanda B; van Rossum, Elisabeth F C

    2016-10-01

    Hair glucocorticoids (cortisol and cortisone) are increasingly used as measures of long-term integrated exposure to glucocorticoid hormones. Glucocorticoids gradually disappear from the hair shaft, which may result from exposure to ultraviolet (UV) radiation in natural sunlight. We aimed to study the influence of sun exposure on hair glucocorticoids. Scalp hair samples were obtained from nine volunteers (median age 33 [range 21-81], 7 females), and part of each hair sample was exposed to three experimental conditions: repeated exposure to natural sunlight for 40h (natural UV), exposure to a high amount of artificial UV radiation, and storage in the dark (control). Hair cortisol (HairF) and cortisone (HairE) were quantified by liquid chromatography-tandem mass spectrometry. When compared to control, HairF was decreased in 9 out of 9 hair samples after natural sunlight exposure (median decrease -3.1pg/mg or -54%, PUV radiation (-4.7pg/mg or -75%, P=0.003). HairE decreased in 8 out of 9 samples, both after natural sunlight (-7.6pg/mg or -32%, P=0.012) and artificial UV (-10.7pg/mg or -52%, P=0.026). Exposure to natural sunlight decreases the glucocorticoid content of scalp hair, apparently through UV radiation, and is therefore an important confounder that should be considered in studies involving the measurement of hair glucocorticoids. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Study of terahertz-radiation-induced DNA damage in human blood leukocytes

    Energy Technology Data Exchange (ETDEWEB)

    Angeluts, A A; Esaulkov, M N; Kosareva, O G; Solyankin, P M; Shkurinov, A P [International Laser Center, M. V. Lomonosov Moscow State University, Moscow (Russian Federation); Gapeyev, A B; Pashovkin, T N [Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region (Russian Federation); Matyunin, S N [Section of Applied Problems at the Presidium of the Russian Academy of Sciences, Moscow (Russian Federation); Nazarov, M M [Institute on Laser and Information Technologies, Russian Academy of Sciences, Shatura, Moscow Region (Russian Federation); Cherkasova, O P [Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2014-03-28

    We have carried out the studies aimed at assessing the effect of terahertz radiation on DNA molecules in human blood leukocytes. Genotoxic testing of terahertz radiation was performed in three different oscillation regimes, the blood leukocytes from healthy donors being irradiated for 20 minutes with the mean intensity of 8 – 200 μW cm{sup -2} within the frequency range of 0.1 – 6.5 THz. Using the comet assay it is shown that in the selected regimes such radiation does not induce a direct DNA damage in viable human blood leukocytes. (biophotonics)

  16. Radiation damage of variscite in historic crafts: Solarization, decolouration, structural changes and spectra from ionoluminescence

    Science.gov (United States)

    Garcia-Guinea, J.; Correcher, V.; Sanchez-Muñoz, L.; Lopez-Arce, P.; Townsend, P. D.; Hole, D. E.

    2008-01-01

    X-ray diffraction measurements, during halogen lamp illumination to simulate sunlight, (TXRD) show a phase transition from variscite (AlPO 4·H 2O) Messbach to variscite Lucin and a loss of the dark green colour. The differential-thermal and thermo-gravimetric (DTA-TG) analyses and thermoluminescence (TL) peaks all depict this first-order phase transition which takes place under sunlight. From the water vaporization temperature up to circa 650 °C, a second-order phase transition progressively occurs from variscite to berlinite (AlPO 4) by loss of a second unit of water with hydrogen bonded to the lattice. The ion beam luminescence (IBL) spectra of the Zamora variscite display a spectral band from 500 to 570 nm attributed to [UO 2] 2+ in phosphates, and another spectral band from 670 to 740 nm is linked with Cr(VI) 3+ defects situated in octahedral Al(VI) 3+ positions. In the hydrous variscite lattice, the Al-O and P-O chemical bonds are mainly covalent; with the degree of covalency of the P-O chemical bond significantly larger than of Al-O. This open structure of variscite, which has a crystal field of reduced strength, involves small shifts of the absorption bands which intensify the blue-green transmission producing the characteristic emerald colour of the dark green variscite of Zamora. These data provide a valuable basis for detection of solarization damage in historic crafts with inlaid variscite in the Museo del Prado (Madrid, Spain).

  17. The impact of locally multiply damaged sites (LMDS) induced by ionizing radiation in mammalian cells

    Energy Technology Data Exchange (ETDEWEB)

    Averbeck, D.; Boucher, D. [Institut Curie-Section de Recherche, UMR2027 CNRS, LCR-V28 du CEA, Centre Universitaire, 91405 Orsay Cedex (France)

    2006-07-01

    Monte Carlo calculations have shown that ionising radiations produce a specific type of clustered cell damage called locally multiply damaged sites or LMDS. These lesions consist of closely positioned single-strand breaks, (oxidative) base damage and DNA double-strand breaks (DSB) in between one helical turn of DNA. As specific markers of radiation-induced damage these lesions are likely to condition biological responses and are thus of great interest for radiation protection. Calculations indicate that there should be more LMDS induced by high than by low LET radiation, and they should be absent in un-irradiated cells. Processes like K-shell activation and local Auger electron emission can be expected to add complex DSB or LMDS, producing significant chromosomal damage. In the discussion of the specificity of ionising radiation in comparison to other genotoxic agents, many arguments have been put forward that these lesions should be particularly deleterious for living cells. Complex lesions of that type should represent big obstacles for DNA repair and give rise to high lethality. Moreover, cellular attempts to repair them could accentuate harm, leading to mutations, genetic instability and cancer. In vitro experiments with oligonucleotides containing an artificially introduced set of base damage and SSB in different combinations have shown that depending on the close positioning of the damage on DNA, repair enzymes, and even whole cell extracts, are unable to repair properly and may stimulate mis-repair. Pulsed field gel electrophoresis (PFGE) in conjunction with enzymatic treatments has been used to detect LMDS in mammalian cells after high and low LET radiation. In order to further define the importance of LMDS for radiation induced cellular responses, we studied the induction of LMDS as a function of radiation dose and dose rate in mammalian cells (CHO and MRC5) using {sup 137}Cs gamma-radiation. Using PFGE and specific glycosylases to convert oxidative damage

  18. Assessment of DNA damage and oxidative stress induced by radiation in Eisenia fetida

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Tae Ho; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Nili, Mohammad [Dawnesh Radiation Research Institute, Barcelona (Spain)

    2012-04-15

    Exposure of eukaryotic cells to ionizing radiation results in the immediate formation of free radicals and the occurrence of oxidative cell damage. Recently International Commission on Radiological Protection (ICRP) requires the effect data of ionizing radiation on non-human biota for the radiological protection of the environment. Based on their radioecological properties and their important role in the soil ecosystem, earthworms have been identified by the ICRP as one of the reference animals and plants (RAPs) to be used in environmental radiation protection. The investigation shows that oxidative stress is closely related to the exposed dose of radiation in the environment. To evaluate oxidative stress by ionizing radiation in the earthworm, we performed several experiments. The comet assay is known as a measurement which is one of the best techniques in assessing the DNA damage by oxidative stress. The SOD is a key enzyme in protecting cells against oxidative stress. An increase in the level of antioxidant enzyme such as SOD indicated that the exposure to radiation caused stress responses. Glutathione oxidation is considered as a maker for detection of reactive oxygen species (ROS). The GSSG levels increased progressively with increased exposure dose of ionizing radiation, which suggested a dose-dependent ROS generation.

  19. TGF-.beta. antagonists as mitigators of radiation-induced tissue damage

    Science.gov (United States)

    Barcellos-Hoff, Mary H.

    1997-01-01

    A method for treating tissue damage caused by radiation is described by use of a TGF-.beta. antagonist, such as an anti-TGF-.beta. antibody or a TGF-.beta. latency associated protein. It is administered not more than a week after exposure, and is particularly useful in mitigating the side effects of breast cancer therapy.

  20. TGF-{beta} antagonists as mitigators of radiation-induced tissue damage

    Science.gov (United States)

    Barcellos-Hoff, M.H.

    1997-04-01

    A method for treating tissue damage caused by radiation is described by use of a TGF-{beta} antagonist, such as an anti-TGF-{beta} antibody or a TGF-{beta} latency associated protein. It is administered not more than a week after exposure, and is particularly useful in mitigating the side effects of breast cancer therapy.

  1. Retinal damage by optical radiation. An alternative approach to current, ACGIH-inspired guidelines

    NARCIS (Netherlands)

    Vos, J.J.; Norren, D. van

    2005-01-01

    Background: The ACGIH guidelines for protection against retinal damage by optical radiation are often difficult to apply due to their lack of transparency. The less known guidelines by the Netherlands Health Council (HCN), dating from 1978 and updated in 1993, might offer a way out in many cases. Me

  2. Stem Cell Therapy to Reduce Radiation-Induced Normal Tissue Damage

    NARCIS (Netherlands)

    Coppes, Rob P.; van der Goot, Annemieke; Lombaert, Isabelle M. A.

    Normal tissue damage after radiotherapy is still a major problem in cancer treatment. Stem cell therapy may provide a means to reduce radiation-induced side effects and improve the quality of life of patients. This review discusses the current status in stem cell research with respect to their

  3. OBJECT KINETIC MONTE CARLO SIMULATIONS OF RADIATION DAMAGE ACCUMULATION IN TUNGSTEN

    Energy Technology Data Exchange (ETDEWEB)

    Nandipati, Giridhar; Setyawan, Wahyu; Roche, Kenneth J.; Kurtz, Richard J.; Wirth, Brian D.

    2016-09-01

    The objective of this work is to understand the accumulation of radiation damage created by primary knock-on atoms (PKAs) of various energies, at 300 K and for a dose rate of 10-4 dpa/s in bulk tungsten using the object kinetic Monte Carlo (OKMC) method.

  4. Protecting the radiation-damaged skin from friction: a mini review

    Energy Technology Data Exchange (ETDEWEB)

    Herst, Patries M [Department of Radiation Therapy, University of Otago, Wellington (New Zealand)

    2014-06-15

    Radiation-induced skin reactions are an unavoidable side effect of external beam radiation therapy, particularly in areas prone to friction and excess moisture such as the axilla, head and neck region, perineum and skin folds. Clinical studies investigating interventions for preventing or managing these reactions have largely focussed on formulations with moisturising, anti-inflammatory, anti-microbial and wound healing properties. However, none of these interventions has emerged as a consistent candidate for best practice. Much less emphasis has been placed on evaluating ways to protect the radiation-damaged skin from friction and excess moisture. This mini review analyses the clinical evidence for barrier products that form a protective layer by adhering very closely to the skin folds and do not cause further trauma to the radiation-damaged skin upon removal. A database search identified only two types of barrier products that fitted these criteria and these were tested in two case series and six controlled clinical trials. Friction protection was most effective when the interventions were used from the start of treatment and continued for several weeks after completion of treatment. Soft silicone dressings (Mepilex Lite and Mepitel Film) and Cavilon No Sting Barrier Film, but not Cavilon Moisturizing Barrier Cream, decreased skin reaction severity, most likely due to differences in formulation and skin build-up properties. It seems that prophylactic use of friction protection of areas at risk could be a worthwhile addition to routine care of radiation-damaged skin.

  5. Radiation-damage-induced phasing: a case study using UV irradiation with light-emitting diodes.

    Science.gov (United States)

    de Sanctis, Daniele; Zubieta, Chloe; Felisaz, Franck; Caserotto, Hugo; Nanao, Max H

    2016-03-01

    Exposure to X-rays, high-intensity visible light or ultraviolet radiation results in alterations to protein structure such as the breakage of disulfide bonds, the loss of electron density at electron-rich centres and the movement of side chains. These specific changes can be exploited in order to obtain phase information. Here, a case study using insulin to illustrate each step of the radiation-damage-induced phasing (RIP) method is presented. Unlike a traditional X-ray-induced damage step, specific damage is introduced via ultraviolet light-emitting diodes (UV-LEDs). In contrast to UV lasers, UV-LEDs have the advantages of small size, low cost and relative ease of use.

  6. Spontaneous perseverative turning in rats with radiation-induced hippocampal damage

    Energy Technology Data Exchange (ETDEWEB)

    Mickley, G.A.; Ferguson, J.L.; Nemeth, T.J.; Mulvihill, M.A.; Alderks, C.E. (Armed Forces Radiobiology Research Institute, Bethesda, MD (USA))

    1989-08-01

    This study found a new behavioral correlate of lesions specific to the dentate granule cell layer of the hippocampus: spontaneous perseverative turning. Irradiation of a portion of the neonatal rat cerebral hemispheres produced hypoplasia of the granule cell layer of the hippocampal dentate gyrus while sparing the rest of the brain. Radiation-induced damage to the hippocampal formation caused rats placed in bowls to spontaneously turn in long, slow bouts without reversals. Irradiated subjects also exhibited other behaviors characteristic of hippocampal damage (e.g., perseveration in spontaneous exploration of the arms of a T-maze, retarded acquisition of a passive avoidance task, and increased horizontal locomotion). These data extend previously reported behavioral correlates of fascia dentata lesions and suggest the usefulness of a bout analysis of spontaneous bowl turning as a measure of nondiscrete-trial spontaneous alternation and a sensitive additional indicator of radiation-induced hippocampal damage.

  7. Pt/In2S3/CdS/Cu2ZnSnS4 Thin Film as an Efficient and Stable Photocathode for Water Reduction under Sunlight Radiation.

    Science.gov (United States)

    Jiang, Feng; Gunawan; Harada, Takashi; Kuang, Yongbo; Minegishi, Tsutomu; Domen, Kazunari; Ikeda, Shigeru

    2015-10-28

    An electrodeposited Cu2ZnSnS4 (CZTS) compact thin film modified with an In2S3/CdS double layer and Pt deposits (Pt/In2S3/CdS/CZTS) was used as a photocathode for water splitting of hydrogen production under simulated sunlight (AM 1.5G) radiation. Compared to platinized electrodes based on a bare CZTS film (Pt/CZTS) and a CZTS film modified with a CdS single layer (Pt/CdS/CZTS), the Pt/In2S3/CdS/CZTS electrode exhibited a significantly high cathodic photocurrent. Moreover, the coverage of the In2S3 layer was found to be effective for stabilization against degradation induced by photocorrosion of the CdS layer. Bias-free water splitting with a power conversion efficiency of 0.28% was achieved by using a simple two-electrode cell consisting of the Pt/In2S3/CdS/CZTS photocathode and a BiVO4 photoanode.

  8. An Automated Method to Quantify Radiation Damage in Human Blood Cells

    Energy Technology Data Exchange (ETDEWEB)

    Gordon K. Livingston, Mark S. Jenkins and Akio A. Awa

    2006-07-10

    Cytogenetic analysis of blood lymphocytes is a well established method to assess the absorbed dose in persons exposed to ionizing radiation. Because mature lymphocytes circulate throughout the body, the dose to these cells is believed to represent the average whole body exposure. Cytogenetic methods measure the incidence of structural aberrations in chromosomes as a means to quantify DNA damage which occurs when ionizing radiation interacts with human tissue. Methods to quantify DNA damage at the chromosomal level vary in complexity and tend to be laborious and time consuming. In a mass casualty scenario involving radiological/nuclear materials, the ability to rapidly triage individuals according to radiation dose is critically important. For high-throughput screening for dicentric chromosomes, many of the data collection steps can be optimized with motorized microscopes coupled to automated slide scanning platforms.

  9. [Damage and functional recovery of the mouse retina after exposure to ionizing radiation and methylnitrosourea].

    Science.gov (United States)

    Vinogradova, Iu V; Tronov, V A; Liakhova, K N; Poplinskaia, V A; Ostrovskiĭ, M A

    2014-01-01

    The eye retina consists of terminally differentiated cells that have lost their ability to proliferate. The death of these cells leads tothe loss of sight. The mice retina is characterized by relatively high resistance to radiation, which is provided by its ability to repair damage caused by environmental factors. The aim of our work was to assess the damaging effect of ionizing radiation and methylnitrosourea (MNU) on the DNA structure in the mouse retina, the functional activity of the retina, and its ability to recover in vivo. The results confirm the ability of the mature retina to structural and functional recovery. Adapting influence of low dose chemical agent increases retina resistance to cytotoxic dose of genotoxicants and prevents degeneration of photoreceptor layer of the retina. The results show the possibility of neurohormesis effect in the mice retina after exposure to ionizing radiation and chemicals.

  10. Annealing behavior of radiation damage in JFET-input operational amplifiers

    Institute of Scientific and Technical Information of China (English)

    Zheng Yuzhan; Lu Wu; Ren Diyuan; Wang Yiyuan; Guo Qi; Yu Xuefeng

    2009-01-01

    The elevated and room temperature annealing behavior of radiation damage in JFET-input operational amplifiers (op-amps) were investigated. High-and low-dose-rate irradiation results show that one of the JFET-input op-amps studied in this paper exhibits enhanced low-dose-rate sensitivity and the other shows time-dependent effect. The offset voltage of both op-amps increases during long-term annealing at room temperature. However, the offset voltage decreases at elevated temperature. The dramatic difference in annealing behavior at room and elevated temperatures indicates the migration behavior of radiation-induced species at elevated and room temperatures. This provides useful information to understand the degradation and annealing mechanisms in JFET-input op-amps under total ionizing radiation. Moreover, the annealing of oxide trapped charges should be taken into consideration, when using elevated temperature methods to evaluate low-dose-rate damage.

  11. A simple model of space radiation damage in GaAs solar cells

    Science.gov (United States)

    Wilson, J. W.; Stith, J. J.; Stock, L. V.

    1983-01-01

    A simple model is derived for the radiation damage of shallow junction gallium arsenide (GaAs) solar cells. Reasonable agreement is found between the model and specific experimental studies of radiation effects with electron and proton beams. In particular, the extreme sensitivity of the cell to protons stopping near the cell junction is predicted by the model. The equivalent fluence concept is of questionable validity for monoenergetic proton beams. Angular factors are quite important in establishing the cell sensitivity to incident particle types and energies. A fluence of isotropic incidence 1 MeV electrons (assuming infinite backing) is equivalent to four times the fluence of normal incidence 1 MeV electrons. Spectral factors common to the space radiations are considered, and cover glass thickness required to minimize the initial damage for a typical cell configuration is calculated. Rough equivalence between the geosynchronous environment and an equivalent 1 MeV electron fluence (normal incidence) is established.

  12. Effect of antioxidant supplementation on digestive enzymes in radiation induced intestinal damage in rats.

    Science.gov (United States)

    Anwar, Mumtaz; Nanda, Neha; Bhatia, Alka; Akhtar, Reyhan; Mahmood, Safrun

    2013-12-01

    Intestinal mucosa, a rapidly proliferating tissue, is highly sensitive to radiation and undergoes apoptosis as a consequence of over generation of oxidative free radicals and the lack of the antioxidants. Thus the present study was designed to investigate the intestinal damage induced by radiation and to study if supplementation of the diet with antioxidant vitamins could ameliorate the intestinal damage and its digestive activity, as determined by the expression of various border enzymes. Swiss Albino rats (150-200 g body weight) were divided into six groups. Group I: Control untreated; Group II: Irradiated; Group III: Irradiated + vitamin A; Group IV: Irradiated + vitamin C; Group V: Irradiated + vitamin E; and Group VI: Irradiated + lycopene. Animals were exposed to whole body γ-radiation from (60)Co at the rate of 8 Gy for 15 min/rat. Intestinal morphology and changes in various digestive enzymes together with, DNA damage was studied in six groups and each group consisted of 18 animals. The gastrointestinal toxicity resulted in malabsorption, diarrhoea, weight loss, loss of appetite, abdominal haemorrhage and hair loss. The activities of sucrase and alkaline phosphatase were elevated and those of lactase, leucine aminopeptidase (LAP) and gamma-glutamyl transpeptidase or tranferase (γ-GTP) were markedly reduced. Antioxidant vitamin A, C or E supplementations prevented changes in brush border enzyme activities as compared to lycopene administration in rat intestine by radiation exposure. Intestinal histology showed that the vitamin supplementation to irradiated rats minimized the intestinal damage in rats. These findings suggest that the epithelial lining of the intestine is highly sensitive to radiation exposure and supplementation of antioxidant vitamins is helpful in minimizing the intestinal damage and supplementation by vitamin E was most potent in ameliorating the intestinal aberrations.

  13. Reproducible radiation-damage processes in proteins irradiated by intense x-ray pulses

    Science.gov (United States)

    Hau-Riege, Stefan P.; Bennion, Brian J.

    2015-02-01

    X-ray free-electron lasers have enabled femtosecond protein nanocrystallography, a novel method to determine the structure of proteins. It allows time-resolved imaging of nanocrystals that are too small for conventional crystallography. The short pulse duration helps in overcoming the detrimental effects of radiation damage because x rays are scattered before the sample has been significantly altered. It has been suggested that, fortuitously, the diffraction process self-terminates abruptly once radiation damage destroys the crystalline order. Our calculations show that high-intensity x-ray pulses indeed trigger a cascade of damage processes in ferredoxin crystals, a particular metalloprotein of interest. However, we found that the damage process is initially not completely random. Correlations exist among the protein monomers, so that Bragg diffraction still occurs in the damaged crystals, despite significant atomic displacements. Our results show that the damage process is reproducible to a certain degree, which is potentially beneficial for the orientation step in single-molecule imaging.

  14. Comparing simulations and test data of a radiation damaged CCD for the Euclid mission

    Science.gov (United States)

    Skottfelt, Jesper; Hall, David; Gow, Jason; Murray, Neil; Holland, Andrew; Prod'homme, Thibaut

    2016-07-01

    The radiation damage effects from the harsh radiative environment outside the Earth's atmosphere can be a cause for concern for most space missions. With the science goals becoming ever more demanding, the requirements on the precision of the instruments on board these missions also increases, and it is therefore important to investigate how the radiation induced damage affects the Charge-Coupled Devices (CCDs) that most of these instruments rely on. The primary goal of the Euclid mission is to study the nature of dark matter and dark energy using weak lensing and baryonic acoustic oscillation techniques. The weak lensing technique depends on very precise shape measurements of distant galaxies obtained by a large CCD array. It is anticipated that over the 6 year nominal lifetime of mission, the CCDs will be degraded to an extent that these measurements will not be possible unless the radiation damage effects are corrected. We have therefore created a Monte Carlo model that simulates the physical processes taking place when transferring signal through a radiation damaged CCD. The software is based on Shockley-Read-Hall theory, and is made to mimic the physical properties in the CCD as close as possible. The code runs on a single electrode level and takes charge cloud size and density, three dimensional trap position, and multi-level clocking into account. A key element of the model is that it takes device specific simulations of electron density as a direct input, thereby avoiding to make any analytical assumptions about the size and density of the charge cloud. This paper illustrates how test data and simulated data can be compared in order to further our understanding of the positions and properties of the individual radiation-induced traps.

  15. Radiation damage in polymer films from grazing-incidence X-ray scattering measurements

    Energy Technology Data Exchange (ETDEWEB)

    Vaselabadi, Saeed Ahmadi [Department of Chemical and Biomolecular Engineering, University of Houston, Houston Texas 77204-4004; Shakarisaz, David [Department of Electrical and Computer Engineering, University of Houston, Houston Texas 77204-4005; Ruchhoeft, Paul [Department of Electrical and Computer Engineering, University of Houston, Houston Texas 77204-4005; Strzalka, Joseph [X-Ray Science Division, Argonne National Laboratory, Argonne Illinois 60439; Stein, Gila E. [Department of Chemical and Biomolecular Engineering, University of Houston, Houston Texas 77204-4004

    2016-02-16

    Grazing-incidence X-ray scattering (GIXS) is widely used to analyze the crystallinity and nanoscale structure in thin polymer lms. However, ionizing radiation will generate free radicals that initiate cross-linking and/or chain scission, and structural damage will impact the ordering kinetics, thermodynamics, and crystallinity in many polymers. We report a simple methodology to screen for beam damage that is based on lithographic principles: lms are exposed to patterns of x-ray radiation, and changes in polymer structure are revealed by immersing the lm in a solvent that dissolves the shortest chains. The experiments are implemented with high throughput using the standard beam line instrumentation and a typical GIXS configuration. The extent of damage (at a fixed radiation dose) depends on a range of intrinsic material properties and experimental variables, including the polymer chemistry and molecular weight, exposure environment, llm thickness, and angle of incidence. The solubility switch for common polymers is detected within 10-60 sec at ambient temperature, and we verified that this first indication of damage corresponds with the onset of network formation in glassy polystyrene and a loss of crystallinity in polyalkylthiophenes. Therefore, grazing-incidence x-ray patterning offers an efficient approach to determine the appropriate data acquisition times for any GIXS experiment.

  16. Early and Late Damages in Chromosome 3 of Human Lymphocytes After Radiation Exposure

    Science.gov (United States)

    Sunagawa, Mayumi; Mangala, Lingegowda; Zhang, Ye; Kahdim, Munira; Wilson, Bobby; Cucinotta, Francis A.; Wu, Honglu

    2011-01-01

    Tumor formation in humans or animals is a multi-step process. An early stage of cancer development is believed to be genomic instability (GI) which accelerates the mutation rate in the descendants of the cells surviving radiation exposure. GI is defined as elevated or persistent genetic damages occurring many generations after the cells are exposed. While early studies have demonstrated radiation-induced GI in several cell types as detected in endpoints such as mutation, apoptosis and damages in chromosomes, the dependence of GI on the quality of radiation remains uncertain. To investigate GI in human lymphocytes induced by both low- and high-LET radiation, we initially exposed white blood cells collected from healthy subjects to gamma rays in vitro, and cultured the cells for multiple generations. Chromosome aberrations were analyzed in cells collected at first mitosis post irradiation and at several intervals during the culture period. Among a number of biological endpoints planned for the project, the multi-color banding fluorescent in situ hybridization (mBAND) allows identification of inversions that were expected to be stable. We present here early and late chromosome aberrations detected with mBAND in chromosome 3 after gamma exposure. Comparison of chromosome damages in between human lymphocytes and human epithelial cells is also discussed

  17. Radiation damage free two-color X-ray ghost diffraction with atomic resolution

    CERN Document Server

    Li, Zheng; Chapman, Henry; Shih, Yanhua

    2015-01-01

    The X-ray free electron lasers (XFEL) can enable diffractive structural determination of protein crystals or single molecules that are too small and radiation-sensitive for conventional X-ray analysis. However the electronic form factor could have been modified during the ultrashort X-ray pulse due to photoionization and electron cascade caused by the intense X-ray pulse. For general X-ray imaging techniques, to minimize radiation damage effect is of major concern to ensure faithful reconstruction of the structure. Here we show that a radiation damage free diffraction can be achieved with an atomic spatial resolution, by using X-ray parametric down-conversion (PDC), and two-color biphoton ghost imaging. We illustrate that formation of the diffractive patterns satisfies a condition analogous to the Bragg equation, with a resolution that could be as fine as the lattice length scale of several Angstrom. Because the samples are illuminated by the optical photons of low energy, they can be free of radiation damage...

  18. Reduction of arsenite-enhanced ultraviolet radiation-induced DNA damage by supplemental zinc

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, Karen L.; King, Brenee S.; Sandoval, Monica M.; Liu, Ke Jian; Hudson, Laurie G., E-mail: lhudson@salud.unm.edu

    2013-06-01

    Arsenic is a recognized human carcinogen and there is evidence that arsenic augments the carcinogenicity of DNA damaging agents such as ultraviolet radiation (UVR) thereby acting as a co-carcinogen. Inhibition of DNA repair is one proposed mechanism to account for the co-carcinogenic actions of arsenic. We and others find that arsenite interferes with the function of certain zinc finger DNA repair proteins. Furthermore, we reported that zinc reverses the effects of arsenite in cultured cells and a DNA repair target protein, poly (ADP-ribose) polymerase-1. In order to determine whether zinc ameliorates the effects of arsenite on UVR-induced DNA damage in human keratinocytes and in an in vivo model, normal human epidermal keratinocytes and SKH-1 hairless mice were exposed to arsenite, zinc or both before solar-simulated (ss) UVR exposure. Poly (ADP-ribose) polymerase activity, DNA damage and mutation frequencies at the Hprt locus were measured in each treatment group in normal human keratinocytes. DNA damage was assessed in vivo by immunohistochemical staining of skin sections isolated from SKH-1 hairless mice. Cell-based findings demonstrate that ssUVR-induced DNA damage and mutagenesis are enhanced by arsenite, and supplemental zinc partially reverses the arsenite effect. In vivo studies confirm that zinc supplementation decreases arsenite-enhanced DNA damage in response to ssUVR exposure. From these data we can conclude that zinc offsets the impact of arsenic on ssUVR-stimulated DNA damage in cells and in vivo suggesting that zinc supplementation may provide a strategy to improve DNA repair capacity in arsenic exposed human populations. - Highlights: • Low levels of arsenite enhance UV-induced DNA damage in human keratinocytes. • UV-initiated HPRT mutation frequency is enhanced by arsenite. • Zinc supplementation offsets DNA damage and mutation frequency enhanced by arsenite. • Zinc-dependent reduction of arsenite enhanced DNA damage is confirmed in vivo.

  19. Radiation damage and sensitization effects on thermoluminescence of LiF:Mg,Ti (TLD-700)

    Science.gov (United States)

    Farag, M. A.; Sadek, A. M.; Shousha, Hany. A.; El-Hagg, A. A.; Atta, M. R.; Kitis, G.

    2017-09-01

    The radiation damage effects and enhancement the thermoluminescence (TL) efficiency of LiF:Mg,Ti (TLD-700)dosimeters via sensitization method were discussed. Attempts to eliminate the effects of damage and sensitization were made using different types of annealing processes. The results showed that after irradiating the dosimeters with dose > 250 Gy of 60Co gamma source, damage effects were observed. The sensitivity of the total area under the curve was decreased by a factor of ∼0.5 after irradiation at a pre-test dose of 2 kGy. However, the effects of radiation damage on each glow-peak are different. The glow-peak 2 was the only peak that was not affected by the high-dose irradiation. It has been shown that the degree of the radiation damage effect is related to the maximum dose-response function, f(D)max of the glow-peak. In general, significant radiation damage effects were observed for the glow-peaks of high f(D)max . Post-irradiation anneal at 280 °C for 30 min causes dramatic effects on the shape of the glow-curve and as well as on the sensitivity of the dosimeters. An increasing by a factor of ∼35 in the sensitivity of the total area under the curve was observed at a pre-test dose of 2 kGy. Improving the sensitivity of peak 7 by a factor of∼22 was the dominant factor in increasing the sensitivity of the dosimeters. On the other hand, an increasing by factors of ∼2.5 and ∼4 was found for peaks 2 and 5 respectively. On the other hand, a decreasing by a factor ∼0.5 was observed for peaks 3 and 4. At pre-test dose levels >250 Gy, a very strange and high intensity tail was observed in the high-temperature region of the glow-curves. The readout anneal was not enough to remove this tail. While, the furnace anneal could eliminate the sensitization effects but not the radiation damage effects on the sensitivity of the dosimeters.

  20. Childhood cancer incidence in relation to sunlight exposure.

    Science.gov (United States)

    Musselman, J R B; Spector, L G

    2011-01-04

    There is increasing interest in the possible association between cancer incidence and vitamin D through its role as a regulator of cell growth and differentiation. Epidemiological studies in adults and one paediatric study suggest an inverse association between sunlight exposure and cancer incidence. We carried out an ecological study using childhood cancer registry data and two population-level surrogates of sunlight exposure, (1) latitude of the registry city or population centroid of the registry nation and (2) annual solar radiation. All models were adjusted for nation-level socioeconomic status using socioeconomic indicators. Latitude and radiation were significantly associated with cancer incidence, and the direction of association was consistent between the surrogates. Findings were not consistent across tumour types. Our ecological study offers some evidence to support an association between sunlight exposure and risk of childhood cancer.

  1. Sunlight exposure and multiple sclerosis in a tropical country.

    Science.gov (United States)

    Espinosa-Ramírez, Guillermo; Ordoñez, Graciela; Flores-Rivera, Jose; Sotelo, Julio

    2014-07-01

    We analysed past and current sun exposure in multiple sclerosis (MS) patients as compared with matched controls in Mexico, a country with tropical climate. In a case-controlled study that include 83 MS patients and 166 matched controls, we inquired about sunlight exposure in two different periods: during adolescence and during the immediate past 5 years. Indicators were: exposure on quotidian and weekend outdoor activities with direct sunlight contact as expressed on frequency by mean number of days, daytime (morning, noon, afternoon), number of hours, visits to sunny places, and use of sunblocking agents. Additional elements were socioeconomic status, skin colour, and antecedent of varicella infection during childhood. MS patients showed a larger proportion of white skin. MS patients had more sunlight exposure during adolescence (80% versus 60%, P = 0·002); this tendency prevailed on current indicators (46% versus 30%, P = 0·02). However, current exposure on weekends (10% versus 22%, P = 0·02) and visits to the beach (64% versus 98%, P = 0·002) were lower in MS than in controls. Mexico gets more sunlight through the year than areas with high incidence of MS; nevertheless, its prevalence has greatly increased over the last decades, making it a relevant emerging disease. Our results indicate that in a tropical country, there is no association between sunlight exposure and the risk to develop MS, given the immunological effects of sunlight exposure either through UV radiation or vitamin D metabolism.

  2. Estimation of potential radiation damage to electronics units in the CLIC tunnel

    CERN Document Server

    Patapenka, Andrei

    2014-01-01

    An electronic unit is required for each CLIC “Two Beam Module”. This study aims to estimate the potential damage due to the prompt radiation to the electronics units installed inside the CLIC Main Linac tunnel. Sets of Monte-Carlo simulations have been done to estimate damage to electronics installed at various locations inside the tunnel. Continuous and point beam losses have been considered for CLIC Main and Drive beams. Lead and iron in combination with a polyethylene layer were investigated as a possible shielding. The upper limits of the estimated quantities are presented for stand alone and shielded electronics.

  3. Radiation damage of SiGe HBT Technologies at different bias configurations

    CERN Document Server

    Ullán, M; Lozano, M; Pellegrini, G; Knoll, D; Heinemann, B

    2008-01-01

    SiGe BiCMOS technologies are being proposed for the Front-end readout of the detectors in the middle region of the ATLAS-Upgrade. The radiation hardness of the SiGe bipolar transistors is being assessed for this application through irradiations with different particles. Biasing conditions during irradiation of bipolar transistors or circuits have an influence on the damage and there is a risk of erroneous results. We have performed several irradiation experiments of SiGe devices from IHP in different bias conditions. We have observed a systematic trend in gamma irradiations, showing a smaller damage in transistors irradiated biased compared to shorted or floating terminals.

  4. A comparison of ionizing radiation damage in CMOS devices from 60Co gamma rays, electrons and protons

    Institute of Scientific and Technical Information of China (English)

    HE Sao-Ping; YAO Zhi-Bin; ZHANG Feng-Qi

    2009-01-01

    Radiation hardened CC4007RH and non-radiation hardened CC4011 devices were irradiated using 80Co gamma rays, 1 MeV electrons and 1--9 MeV protons to compare the ionizing radiation damage of the gamma rays with the charged particles. For all devices examined, with experimental uncertainty, the radiation induced threshold voltage shifts (△Vth) generated by 60Co gamma rays are equal to that of 1 MeV electron and 1-7 MeV proton radiation under 0 gate bias condition. Under 5 V gate bias condition, the distinction of threshold voltage shifts (△Vth) generated by 60Co gamma rays and 1 MeV electrons irradiation are not large, and the radiation damage for protons below 9 MeV is always less than that of 60Co gamma rays. The lower energy the proton has, the less serious the radiation damage becomes.

  5. Radiation Tolerant Interfaces: Influence of Local Stoichiometry at the Misfit Dislocation on Radiation Damage Resistance of Metal/Oxide Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Shutthanandan, Vaithiyalingam [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland WA 99352 USA; Choudhury, Samrat [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos NM 87545 USA; Manandhar, Sandeep [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland WA 99352 USA; Kaspar, Tiffany C. [Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland WA 99352 USA; Wang, Chongmin [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland WA 99352 USA; Devaraj, Arun [Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland WA 99352 USA; Wirth, Brian D. [Department of Nuclear Engineering, University of Tennessee, Knoxville TN 37996 USA; Thevuthasan, Suntharampilli [Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland WA 99352 USA; Hoagland, Richard G. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos NM 87545 USA; Dholabhai, Pratik P. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos NM 87545 USA; Uberuaga, Blas P. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos NM 87545 USA; Kurtz, Richard J. [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland WA 99352 USA

    2017-04-24

    To understand how variations in interface properties such as misfit-dislocation density and local chemistry affect radiation-induced defect absorption and recombination, we have explored a model system of CrxV1-x alloy epitaxial films deposited on MgO single crystals. By controlling film composition, the lattice mismatch with MgO was adjusted so that the misfit-dislocation density varies at the interface. These interfaces were exposed to irradiation and in situ results show that the film with a semi-coherent interface (Cr) withstands irradiation while V film, which has similar semi-coherent interface like Cr, showed the largest damage. Theoretical calculations indicate that, unlike at metal/metal interfaces, the misfit dislocation density does not dominate radiation damage tolerance at metal/oxide interfaces. Rather, the stoichiometry, and the precise location of the misfit-dislocation density relative to the interface, drives defect behavior. Together, these results demonstrate the sensitivity of defect recombination to interfacial chemistry and provide new avenues for engineering radiation-tolerant nanomaterials.

  6. Mechanisms of Radiation Damage Generated by Ionizing Radiation in Optical Waveguides

    Science.gov (United States)

    1988-09-01

    SUMMARY OF APPENDIX B "Optical scattering and SPR study of ZBLAN glass : Dependence on preparation and processing methods" LMater. Sci. Forum 19-20...studied the types of centers created by ionizing radiation in ZBLAN (ZrF 4, BaF 2 , LaF 3, AlF 3 , and NaF) glass . Samples of ZBLAN were prepared using...radiation-induced centers in ZBLAN glass depend strongly on the glass -processing conditions. For example, ZBLAN glasses processed with CC14 yield paramagnetic

  7. Radiation damage study of thin YAG:Ce scintillator using low-energy protons

    Science.gov (United States)

    Novotný, P.; Linhart, V.

    2017-07-01

    Radiation hardness of a 50 μ m thin YAG:Ce scintillator in a form of dependence of a signal efficiency on 3.1 MeV proton fluence was measured and analysed using X-ray beam. The signal efficiency is a ratio of signals given by a CCD chip after and before radiation damage. The CCD chip was placed outside the primary beam because of its protection from damage which could be caused by radiation. Using simplified assumptions, the 3.1 MeV proton fluences were recalculated to: ṡ 150 MeV proton fluences with intention to estimate radiation damage of this sample under conditions at proton therapy centres during medical treatment, ṡ 150 MeV proton doses with intention to give a chance to compare radiation hardness of the studied sample with radiation hardness of other detectors used in medical physics, ṡ 1 MeV neutron equivalent fluences with intention to compare radiation hardness of the studied sample with properties of position sensitive silicon and diamond detectors used in nuclear and particle physics. The following results of our research were obtained. The signal efficiency of the studied sample varies slightly (± 3%) up to 3.1 MeV proton fluence of c. (4 - 8) × 1014 cm-2. This limit is equivalent to 150 MeV proton fluence of (5 - 9) × 1016 cm-2, 150 MeV proton dose of (350 - 600) kGy and 1 MeV neutron fluence of (1 - 2) × 1016 cm-2. Beyond the limit, the signal efficiency goes gradually down. Fifty percent decrease in the signal efficiency is reached around 3.1 MeV fluence of (1 - 2) × 1016 cm-2 which is equivalent to 150 MeV proton fluence of around 2 × 1018 cm-2, 150 MeV proton dose of around 15 MGy and 1 MeV neutron equivalent fluence of (4 - 8) × 1017 cm-2. In contrast with position sensitive silicon and diamond radiation detectors, the studied sample has at least two order of magnitude greater radiation resistance. Therefore, YAG:Ce scintillator is a suitable material for monitoring of primary beams of particles of ionizing radiation.

  8. [Most common skin disorders caused by excessive exposure to sunlight].

    Science.gov (United States)

    Zitás, Éva; Mészáros, Judit

    2016-01-17

    The healing properties of sunlight has been known for millennia, however the gradual deterioration of the ozone layer and the increased use of sun tanning beds in recent decades are causing an increase in skin damaging ultraviolet exposure. In this article the most common photodermatoses and the principles of their treatments are reviewed.

  9. Extract of Xylopia aethiopica (Annonaceae) protects against gamma-radiation induced testicular damage in Wistar rats.

    Science.gov (United States)

    Adaramoye, Oluwatosin Adekunle; Adedara, Isaac Adegboyega; Popoola, Bosede; Farombi, Ebenezer Olatunde

    2010-01-01

    Ionizing radiation is an important environmental risk factor and, a major therapeutic agent for cancer treatment. This study was designed to evaluate the protective effect of extract of Xylopia aethiopica (XA) on gamma-radiation-induced testicular damage in rats. Vitamin C (VC) served as the reference antioxidant during the study. The study consists of 4 groups of 11 rats each. Group I received corn oil (vehicle), groups II and IV were pretreated with XA (250 mg/kg) and VC (250mg/kg) for 6 weeks before and 8 weeks after exposure to gamma-radiation; group III was exposed to a single dose of gamma-radiation (5 Gy). Biochemical analysis revealed that gamma-irradiation caused a significant increase (p testicular lipid peroxidation (LPO) levels by 217% and 221%, respectively. Irradiated rats had markedly decreased testicular catalase (CAT), superoxide dismutase (SOD), glutathione-S-transferase (GST), and reduced glutathione (GSH) levels. Irradiation resulted in 59% and 40% decreases in spermatozoa motility and live/dead sperm count, respectively, and a 161% increase in total sperm abnormalities. Histologically, testes of the irradiated rats showed extensive degenerative changes in the seminiferous tubules and defoliation of spermatocytes. Supplementation of XA and VC reversed the adverse effects of gamma-radiation on biochemical and histological indices of the rats. These findings demonstrated that Xylopia aethiopica has a protective effect by inhibiting oxidative damage in testes of irradiated rats.

  10. ON01210.Na (Ex-RAD® mitigates radiation damage through activation of the AKT pathway.

    Directory of Open Access Journals (Sweden)

    Anthony D Kang

    Full Text Available Development of radio-protective agents that are non-toxic is critical in light of ever increasing threats associated with proliferation of nuclear materials, terrorism and occupational risks associated with medical and space exploration. In this communication, we describe the discovery, characterization and mechanism of action of ON01210.Na, which effectively protects mouse and human bone marrow cells from radiation-induced damage both in vitro and in vivo. Our results show that treatment of normal fibroblasts with ON01210.Na before and after exposure to ionizing radiation provides dose dependent protection against radiation-induced damage. Treatment of mice with ON01210.Na prior to radiation exposure was found to result in a more rapid recovery of their hematopoietic system. The mechanistic studies described here show that ON01210.Na manifests its protective effects through the up-regulation of PI3-Kinase/AKT pathways in cells exposed to radiation. These results suggest that ON 01210.Na is a safe and effective radioprotectant and could be a novel agent for use in radiobiological disasters.

  11. ON01210.Na (Ex-RAD®) mitigates radiation damage through activation of the AKT pathway.

    Science.gov (United States)

    Kang, Anthony D; Cosenza, Stephen C; Bonagura, Marie; Manair, Manoj; Reddy, M V Ramana; Reddy, E Premkumar

    2013-01-01

    Development of radio-protective agents that are non-toxic is critical in light of ever increasing threats associated with proliferation of nuclear materials, terrorism and occupational risks associated with medical and space exploration. In this communication, we describe the discovery, characterization and mechanism of action of ON01210.Na, which effectively protects mouse and human bone marrow cells from radiation-induced damage both in vitro and in vivo. Our results show that treatment of normal fibroblasts with ON01210.Na before and after exposure to ionizing radiation provides dose dependent protection against radiation-induced damage. Treatment of mice with ON01210.Na prior to radiation exposure was found to result in a more rapid recovery of their hematopoietic system. The mechanistic studies described here show that ON01210.Na manifests its protective effects through the up-regulation of PI3-Kinase/AKT pathways in cells exposed to radiation. These results suggest that ON 01210.Na is a safe and effective radioprotectant and could be a novel agent for use in radiobiological disasters.

  12. How Magnetotactic Bacteria Respond to Radiation Induced Stress and Damage: Comparative Genomics Evidences for Evolutionary Adaptation

    Science.gov (United States)

    Wang, Y.; Pan, Y.

    2015-12-01

    Solar radiation and galactic cosmic radiation is believed to be major restriction factors influencing survival and evolution of life. On planet earth, geomagnetic field along with atmosphere protect living beings from the harmful radiation. During a geomagnetic reversal or excursion, however, the efflux of charged particles on earth surface would increase as the shielding effect of magnetic field decrease. The stratospheric ozone can also be partially stripped away by solar wind when the strength of the field is weak, leading to an increasing ultraviolet radiation penetration to the earth surface. However, studies on the mechanism of radiation induced stress and damage are focused only on bacteria that have no response to magnetic field. This study was motivated by the need to fill the gap upon knowledge of that on magnetic field sensitive microorganism. Magnetotactic bacteria (MTB) are a group of microbes that are able to synthesis intracellular nano-sized magnetic particles (named magnetosomes). These chain-arranged magnetosomes help MTB sense and swim along the magnetic field to find their optimal living environment efficiently. In this paper, in silico prediction of stress and damage repair genes in response to different radiation were carried out on the complete genome of four nonmagnetotactic and four magnetotactic spirilla. In silico analyses of the genomes of magnetic field sensitive and non-sensitive spirilla revealed: 1) all strains contain genes for regulate responses superoxide and peroxide stress, DNA pyrimidine dimer and string breaks; 2) non-magnetotactic spirilla have more genes dealing with oxidative stress, while magnetotactic spirilla may benefit from magnetotaxis by swimming into oxic-anoxic zone away from oxidative stress and direct radiation damage; yet, the lipid hydroperoxide peroxidase gene in MTB may be responsible for possible ROS generated by the membrane enveloped magnetite magnetosome; 3) magnetotactic spirilla possess SOS rec

  13. Radiation Damage Modeling for 3D Pixel Sensors in the ATLAS Detector

    CERN Document Server

    Wallangen, Veronica; The ATLAS collaboration

    2017-01-01

    Silicon Pixel detectors are at the core of the current and planned upgrade of the ATLAS detector. As the detector in closest proximity to the interaction point, these detectors will be subjected to a significant amount of radiation over their lifetime: prior to the HL-LHC, the innermost layers will receive a fluence in excess of 10^15 neq/cm2 and the HL-LHC detector upgrades must cope with an order of magnitude higher fluence integrated over their lifetimes. This poster presents the details of a new digitization model that includes radiation damage effects to the 3D Pixel sensors for the ATLAS Detector.

  14. Expression of c-myc gene as an early indicator of late radiation damage of kidney

    Energy Technology Data Exchange (ETDEWEB)

    Otsuka, Makoto; Hatakenaka, Masamitsu [Kyushu Univ., Fukuoka (Japan). Dept. of Genetics Medical Inst. of Bioregulation; Masuda, Koji

    1998-02-01

    We have previously described the increased proliferation and appearance of abnormally large nuclei in renal proximal tubule cells after radiation. A model has been proposed that the large nuclear cells might be dying and the increased proliferation might lead to mitotic death of these cells and cause functional damage. We measured the amount of c-myc transcript taking the ratio of densities of bands for irradiated left kidney to unirradiated right kidney after RT-PCR procedure on 24 hours after 9, 12 and 15 Gy irradiation, and found positive in 1 out of 10 after 9 Gy, 6 out of 10 after 12 Gy and 9 out of 10 after 15 Gy. Measuring c-myc expression seems to be a potential very early indicator of late radiation damage of kidney. (author)

  15. Compound Poisson Processes and Clustered Damage of Radiation Induced DNA Double Strand Breaks

    Science.gov (United States)

    Gudowska-Nowak, E.; Ritter, S.; Taucher-Scholz, G.; Kraft, G.

    2000-05-01

    Recent experimental data have demonstrated that DNA damage induced by densely ionizing radiation in mammalian cells is distributed along the DNA molecule in the form of clusters. The principal constituent of DNA damage are double-strand breaks (DSB) which are formed when the breaks occur in both DNA strands and are directly opposite or separated by only a few base pairs. DSBs are believed to be most important lesions produced in chromosomes by radiation; interaction between DSBs can lead to cell killing, mutation or carcinogenesis. The paper discusses a model of clustered DSB formation viewed in terms of compound Poisson process along with the predictive essay of the formalism in application to experimental data.

  16. Synchrotron Powder Diffraction Study of Radiation Damage in Langmuir Blodgett Nanotemplate Crystallised Protein

    Directory of Open Access Journals (Sweden)

    Jonathan P. Wright

    2014-01-01

    Full Text Available Polycrystalline samples of lysozyme were prepared with and without a Langmuir-Blodgett (LB thin film template via both the hanging drop method and batch crystallisation. Powder diffraction methods are used to compare these samples and to measure their resistance to radiation damage at room temperature. The X-ray induced amorphisation of the samples was followed as a function of time and it was shown that diffraction does not entirely disappear even at very long exposure times. Two distinct kinetic timescales are evident suggesting that early and late stage processes are quite different. Radiation damage was also shown to be localized in the sample in the region where the beam impinges.

  17. Molecular dynamics study of radiation damage and microstructure evolution of zigzag single-walled carbon nanotubes under carbon ion incidence

    Energy Technology Data Exchange (ETDEWEB)

    Li, Huan [Department of Nuclear Science & Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing (China); Tang, Xiaobin, E-mail: tangxiaobin@nuaa.edu.cn [Department of Nuclear Science & Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing (China); Jiangsu Key Laboratory of Nuclear Energy Equipment Materials Engineering, Nanjing (China); Chen, Feida; Huang, Hai; Liu, Jian [Department of Nuclear Science & Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing (China); Chen, Da [Department of Nuclear Science & Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing (China); Jiangsu Key Laboratory of Nuclear Energy Equipment Materials Engineering, Nanjing (China)

    2016-07-01

    Highlights: • Various incident sites of CNTs are classified into three types for the first time. • Different ion energies and fluences are considered to study the radiation damage. • CNTs have ability to heal the radiation-induced damage at higher temperature. • Stability of a large-diameter tube excels in a slim one under the same conditions. - Abstract: The radiation damage and microstructure evolution of different zigzag single-walled carbon nanotubes (SWCNTs) were investigated under incident carbon ion by molecular dynamics (MD) simulations. The radiation damage of SWCNTs under incident carbon ion with energy ranging from 25 eV to 1 keV at 300 K showed many differences at different incident sites, and the defect production increased to the maximum value with the increase in incident ion energy, and slightly decreased but stayed fairly stable within the majority of the energy range. The maximum damage of SWCNTs appeared when the incident ion energy reached 200 eV and the level of damage was directly proportional to incident ion fluence. The radiation damage was also studied at 100 K and 700 K and the defect production decreased distinctly with rising temperature because radiation-induced defects would anneal and recombine by saturating dangling bonds and reconstructing carbon network at the higher temperature. Furthermore, the stability of a large-diameter tube surpassed that of a thin one under the same radiation environments.

  18. Neutron flux spectra and radiation damage parameters for the Russian Bor-60 and SM-2 reactors

    Energy Technology Data Exchange (ETDEWEB)

    Karasiov, A.V. [D.V. Efremov Scientific Rresearch Institute of Electrophysical Apparatus, St. Petersburg (Russian Federation); Greenwood, L.R. [Pacific Northwest Laboratory, Richland, WA (United States)

    1995-04-01

    The objective is to compare neutron irradiation conditions in Russian reactors and similar US facilities. Neutron fluence and spectral information and calculated radiation damage parameters are presented for the BOR-60 (Fast Experimental Reactor - 60 MW) and SM-2 reactors in Russia. Their neutron exposure characteristics are comparable with those of the Experimental Breeder Reactor (ERB-II), the Fast Flux Test Facility (FFTF), and the High Flux Isotope Reactor (HFIR) in the United States.

  19. A quantum mechanical scheme to reduce radiation damage in electron microscopy

    CERN Document Server

    Okamoto, Hiroshi; Fink, Hans-Werner

    2015-01-01

    We show that radiation damage to unstained biological specimens is not an intractable problem in electron microscopy. When a structural hypothesis of a specimen is available, quantum mechanical principles allow us to verify the hypothesis with a very low electron dose. Realization of such a concept requires precise control of the electron wave front. Based on a diffractive electron optical implementation, we demonstrate the feasibility of this new method by both experimental and numerical investigations.

  20. Some recent results of the silicon detector radiation damage study by the RD2 collaboration

    Energy Technology Data Exchange (ETDEWEB)

    Anghinolfi, F. [CERN, Geneva (Switzerland); Bates, S. [CERN, Geneva (Switzerland); Bardos, R. [School of Physics, University of Melbourne, Parkville, Victoria 3052 (Australia); Bonino, R. [DPNC, Geneva University, Geneva (Switzerland); Chilingarov, A. [CERN, Geneva (Switzerland); Clark, A.G. [DPNC, Geneva University, Geneva (Switzerland); Feick, H. [1. Institut fuer Experimentalphysik, Universitaet Hamburg, D-20355 Hamburg (Germany); Fretwurst, E. [1. Institut fuer Experimentalphysik, Universitaet Hamburg, D-20355 Hamburg (Germany); Glaser, M. [CERN, Geneva (Switzerland); Gorfine, G. [School of Physics, University of Melbourne, Parkville, Victoria 3052 (Australia); Goessling, C. [Institut fuer Physik, Universitaet Dortmund, D-4600 Dortmund (Germany); Jarron, P. [CERN, Geneva (Switzerland); Kambara, H. [DPNC, Geneva University, Geneva (Switzerland); Lindstroem, G. [1. Institut fuer Experimentalphysik, Universitaet Hamburg, D-20355 Hamburg (Germany); Lisowski, B. [Institut fuer Physik, Universitaet Dortmund, D-4600 Dortmund (Germany); Moorhead, G.F. [School of Physics, University of Melbourne, Parkville, Victoria 3052 (Australia); Munday, D.J. [Cambridge Univ. (United Kingdom). Cavendish Lab.; Parker, M.A. [Cambridge Univ. (United Kingdom). Cavendish Lab.; Perrin, E. [DPNC, Geneva University, Geneva (Switzerland); Pilath, S. [Institut fuer Physik, Universitaet Dortmund, D-4600 Dortmund (Germany); Rolf, A. [Institut fuer Physik, Universitaet Dortmund, D-4600 Dortmund (Germany); Schulz, T. [1. Institut fuer Experimentalphysik, Universitaet Hamburg, D-20355 Hamburg (Germany); Taylor, G.N. [School of Physics, University of Melbourne, Parkville, Victoria 3052 (Australia); Teiger, J. [Centre d`Etudes Nucleaires de Saclay, F-91191 Gif-sur-Yvette (France); Tovey, S.N. [School of Physics, University of Melbourne, Parkville, Victoria 3052 (Australia); Uhlmann, T.M. [1. Institut fuer Experimentalphysik, Universitaet Hamburg, D-20355 Hamburg (Germany)

    1995-06-01

    Recent results by the RD2 Collaboration of a study of radiation damage of silicon detectors for the ATLAS detector at LHC are presented. The detectors have been irradiated by neutrons with fluences of up to 1.5x10{sup 14} neutrons/cm{sup 2}. The electric field in the detectors before and after type inversion, the depletion voltage and the dark current were studied. (orig.).

  1. Measurement of DNA damage after exposure to 2450 MHz electromagnetic radiation.

    Science.gov (United States)

    Malyapa, R S; Ahern, E W; Straube, W L; Moros, E G; Pickard, W F; Roti Roti, J L

    1997-12-01

    Recent reports suggest that exposure to 2450 MHz electromagnetic radiation causes DNA single-strand breaks (SSBs) and double-strand breaks (DSBs) in cells of rat brain irradiated in vivo (Lai and Singh, Bioelectromagnetics 16, 207-210, 1995; Int. J. Radiat. Biol. 69, 513-521, 1996). Therefore, we endeavored to determine if exposure of cultured mammalian cells in vitro to 2450 MHz radiation causes DNA damage. The alkaline comet assay (single-cell gel electrophoresis), which is reportedly the most sensitive method to assay DNA damage in individual cells, was used to measure DNA damage after in vitro 2450 MHz irradiation. Exponentially growing U87MG and C3H 10T1/2 cells were exposed to 2450 MHz continuous-wave (CW) radiation in specially designed radial transmission lines (RTLs) that provided relatively uniform microwave exposure. Specific absorption rates (SARs) were calculated to be 0.7 and 1.9 W/kg. Temperatures in the RTLs were measured in real time and were maintained at 37 +/- 0.3 degrees C. Every experiment included sham exposure(s) in an RTL. Cells were irradiated for 2 h, 2 h followed by a 4-h incubation at 37 degrees C in an incubator, 4 h and 24 h. After these treatments samples were subjected to the alkaline comet assay as described by Olive et al. (Exp. Cell Res. 198, 259-267, 1992). Images of comets were digitized and analyzed using a PC-based image analysis system, and the "normalized comet moment" and "comet length" were determined. No significant differences were observed between the test group and the controls after exposure to 2450 MHz CW irradiation. Thus 2450 MHz irradiation does not appear to cause DNA damage in cultured mammalian cells under these exposure conditions as measured by this assay.

  2. Assessment of Radiation Damage to the Structural Material of EAST Tokamak

    Institute of Scientific and Technical Information of China (English)

    Chen Yixue; Wu Yican

    2005-01-01

    Radiation damage to structural material of fusion facilities is of high concern for safety. The superconducting tokamak EAST will conduct D-D plasma experiments with the neutron production of 1015 neutrons per second. To evaluate the material radiation damage a programme system has been devised with the Monte Carlo transport code MCNP-4C, the inventory code FISPACT99, a specific interface, and the fusion evaluated nuclear data library FENDL-2.The key nuclear responses, i.e. fast neutron flux, displacement per atom, and the helium and hydrogen production, are calculated for the structural material SS-316L of the first wall, and the vacuum vessel, using this programme. The results demonstrate that the radiation damage to the structural material is so little that it will not lead to any significant change of material properties according to the reference design. This indicates that there is a large potential space for EAST to test advanced operation regime from the viewpoint of structural material safety.

  3. Prevention of radiation damages with antioxidative nutritional factors and analysis of the modification

    Energy Technology Data Exchange (ETDEWEB)

    Umegaki, Keizo; Esashi, Takatoshi [National Inst. of Health and Nutrition, Tokyo (Japan)

    1998-02-01

    The effects of dietary vitamine E, C and carotene on the damages of bone marrow DNA were investigated with mice exposed to X-ray radiation as the functions of radiation dose and time after the radiation. The administrations of vit E and vit C had little preventive effects on the generation of DNA damages due to X-ray irradiation. This may be attributed to small intake of those vitamines by bone marrow. On the contrary, the administration of {beta}-carotene from donaliella, a green algae at a dose of 300 mg/kg of body weight for two weeks significantly repressed the production of DNA damages by X-ray irradiation at 0.3 Gy, whereas the administration of carotene from palm oil had no effects. The vitamine E level was markedly reduced by either administration of the two carotenes to a level nearly 1/100-1/50 of the normal level. This study suggests that to investigate the effects of an antioxidant in vivo, it is important to consider its concentration in the region concerned as well as the effects of other antioxidants. (M.N.)

  4. Radiation damage and luminescence properties of gamma aluminum oxynitride transparent ceramic

    Science.gov (United States)

    Du, Xinhua; Yao, Shiyue; Jin, Xihai; Chen, Haohong; Li, Weifeng; Liang, Bo

    2015-09-01

    This paper reports on the radiation damage of gamma aluminum oxynitride (γ-AlON) transparent ceramic, which remarkably degrades UV-vis transparency and hence limits its applications in optoelectronic devices. The radiation-induced optical absorption of the as-sintered γ-AlON consists of at least two subbands: one is in the UV region with a peak at 270 nm and the other optical absorption band centers at 550 nm, covering the whole visible light spectrum, which makes the sample colored. Interestingly, all the radiation-induced color centers can be completely ‘bleached’ by low temperature annealing. In the thermoluminescence curve, we observed a broad luminescence in the range of 25-300 °C with the peak at 120 °C. Furthermore, the x-ray excited luminescence spectra revealed that there exist multiple emission centers in the γ-AlON. Based on this experimental fact, the radiation damage and luminescent mechanisms were studied. These optical properties of the γ-AlON are considered to be related to defect states. In the as-sintered γ-AlON, charge balancing is realized by the co-existence of \\text{V}\\text{Al}\\prime\\prime \\prime and \\text{O}\\text{N}\\bullet , and the predominant defect form is ≤ft[\\text{V}\\text{Al}\\prime\\prime \\prime-\\text{3O}\\text{N}\\bullet\\right] , which is optically inactive and no optical absorption occurs. However, isolated \\text{V}\\text{Al}\\prime\\prime \\prime and \\text{O}\\text{N}\\bullet can be formed by irradiation and it is these that are responsible for the radiation damage of γ-AlON transparent ceramic. In the end, the UV absorption and visible-light absorption in the irradiated sample were ascribed to VAl-related and ON-related intrinsic defects, respectively.

  5. Low intensity microwave radiation induced oxidative stress, inflammatory response and DNA damage in rat brain.

    Science.gov (United States)

    Megha, Kanu; Deshmukh, Pravin Suryakantrao; Banerjee, Basu Dev; Tripathi, Ashok Kumar; Ahmed, Rafat; Abegaonkar, Mahesh Pandurang

    2015-12-01

    Over the past decade people have been constantly exposed to microwave radiation mainly from wireless communication devices used in day to day life. Therefore, the concerns over potential adverse effects of microwave radiation on human health are increasing. Until now no study has been proposed to investigate the underlying causes of genotoxic effects induced by low intensity microwave exposure. Thus, the present study was undertaken to determine the influence of low intensity microwave radiation on oxidative stress, inflammatory response and DNA damage in rat brain. The study was carried out on 24 male Fischer 344 rats, randomly divided into four groups (n=6 in each group): group I consisted of sham exposed (control) rats, group II-IV consisted of rats exposed to microwave radiation at frequencies 900, 1800 and 2450 MHz, specific absorption rates (SARs) 0.59, 0.58 and 0.66 mW/kg, respectively in gigahertz transverse electromagnetic (GTEM) cell for 60 days (2h/day, 5 days/week). Rats were sacrificed and decapitated to isolate hippocampus at the end of the exposure duration. Low intensity microwave exposure resulted in a frequency dependent significant increase in oxidative stress markers viz. malondialdehyde (MDA), protein carbonyl (PCO) and catalase (CAT) in microwave exposed groups in comparison to sham exposed group (pmicrowave exposed groups (pmicrowave exposed animal (pmicrowave exposed groups as compared to their corresponding values in sham exposed group (pmicrowave radiation induces oxidative stress, inflammatory response and DNA damage in brain by exerting a frequency dependent effect. The study also indicates that increased oxidative stress and inflammatory response might be the factors involved in DNA damage following low intensity microwave exposure.

  6. Low doses of ionizing radiation to mammalian cells may rather control than cause DNA damage

    Energy Technology Data Exchange (ETDEWEB)

    Feinendegen, L.E. [Brookhaven National Lab., Upton, NY (United States). Medical Dept.; Bond, V.P. [Washington State Univ., Richland, WA (United States); Sondhaus, C.A. [Univ. of Arizona, Tucson, AZ (United States). Dept. of Radiology and Radiation Control Office; Altman, K.I. [Univ. of Rochester Medical Center, NY (United States). Dept. of Biochemistry and Biophysics

    1998-12-31

    This report examines the origin of tissue effects that may follow from different cellular responses to low-dose irradiation, using published data. Two principal categories of cellular responses are considered. One response category relates to the probability of radiation-induced DNA damage. The other category consists of low-dose induced metabolic changes that induce mechanisms of DNA damage mitigation, which do not operate at high levels of exposure. Modeled in this way, tissue is treated as a complex adaptive system. The interaction of the various cellular responses results in a net tissue dose-effect relation that is likely to deviate from linearity in the low-dose region. This suggests that the LNT hypothesis should be reexamined. This paper aims at demonstrating tissue effects as an expression of cellular responses, both damaging and defensive, in relation to the energy deposited in cell mass, by use of microdosimetric concepts.

  7. Radiation damage and annealing in 1310 nm InGaAsP/InP lasers for the CMS tracker

    CERN Document Server

    Gill, K; Grabit, R; Jensen, F; Vasey, F

    2000-01-01

    Radiation damage in 1310 nm InGaAsP/InP multi-quantum-well lasers caused by 0.8 MeV neutrons is compared with the damage from other radiation sources, in terms of the increase in laser threshold current. The annealing behavior is then presented both in terms of both temperature and forward-bias current dependence. The annealing can be described by a model where radiation induced defects have a uniform distribution of activation energies for annealing. This model can then be used to predict the long-term damage expected for lasers operating inside the CMS tracker. (19 refs).

  8. Damage induced by pulsed IR laser radiation at transitions between different tissues

    Science.gov (United States)

    Frenz, Martin; Greber, Charlotte M.; Romano, Valerio; Forrer, Martin; Weber, Heinz P.

    1991-06-01

    Due to their strong absorption in water IR-lasers are excellent sources for precision cutting with minimal thermal damage in various fields of medicine. To understand the laser tissue interaction process one has to take into account the liquefaction of target material at the region of radiation impact. The dynamics of the created liquid may cause unexpected and undesirable effects for surgical laser applications. We studied the thermal damage along the walls of incision craters in terms of the elastic material properties and the dynamics of the drilling process. We show that the extension of thermally altered tissue is strongly influenced by the amount of hot liquefied tissue material remaining in the crater. When drilling into mechanically homogeneous materials this amount is essentially determined by the laser intensity used. However, when drilling through a composite structure consisting of various tissue types with different material properties, this is no longer the case. Even at low intensities, the damage zone varies substantially between the different layers. In our investigations we compared histologically and ultrastructurally the instantaneously created damage in the connective tissue and the subjacent skeletal muscle of skin after laser cutting, with long-time heating injuries. This comparison allows a differentiation between thermal and mechanical damage and an estimation of the minimum temperature created in the crater during the laser impact. The light microscopical examinations shows that the thermal damage in the connective tissue is about three times smaller than in the subjacent muscle layer. Comparative studies made with a composite structure consisting of the tissue substitutes gelatin and agar reveal that the unexpectedly large damage in the skeletal muscle layer is a result of the abrupt change of the elastic properties at the material transition. This discontinuity changes the ejection dynamics leading to a confinement of hot liquefied

  9. Ionizing radiation-induced DNA injury and damage detection in patients with breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Borrego-Soto, Gissela; Ortiz-Lopez, Rocio; Rojas-Martinez, Augusto, E-mail: arojasmtz@gmail.com, E-mail: augusto.rojasm@uanl.mx [Departamento de Bioquímica y Medicina Molecular, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, Nuevo León (Mexico)

    2015-10-15

    Breast cancer is the most common malignancy in women. Radiotherapy is frequently used in patients with breast cancer, but some patients may be more susceptible to ionizing radiation, and increased exposure to radiation sources may be associated to radiation adverse events. This susceptibility may be related to deficiencies in DNA repair mechanisms that are activated after cell-radiation, which causes DNA damage, particularly DNA double strand breaks. Some of these genetic susceptibilities in DNA-repair mechanisms are implicated in the etiology of hereditary breast/ovarian cancer (pathologic mutations in the BRCA 1 and 2 genes), but other less penetrant variants in genes involved in sporadic breast cancer have been described. These same genetic susceptibilities may be involved in negative radiotherapeutic outcomes. For these reasons, it is necessary to implement methods for detecting patients who are susceptible to radiotherapy-related adverse events. This review discusses mechanisms of DNA damage and repair, genes related to these functions, and the diagnosis methods designed and under research for detection of breast cancer patients with increased radiosensitivity. (author)

  10. Irradiation damage to frog inner ear during synchrotron radiation tomographic investigation

    Energy Technology Data Exchange (ETDEWEB)

    Boistel, Renaud [Equipe Communications Acoustiques, NAMC, CNRS UMR 8620, F-91405 Orsay (France); CNRS UMR 7179 ' Mecanismes adaptatifs: des organismes aux communautes' , Departement ' Ecologie et Gestion de la Biodiversite' , Museum National d' Histoire Naturelle, 57 rue Cuvier, case postale 55, 75231 Paris Cedex 5 (France); Univ Paris Sud, F-91405 Orsay (France); European Synchrotron Radiation Facility, B.P. 220, F-38043 Grenoble (France)], E-mail: boistel@mnhn.fr; Pollet, Nicolas [Univ Paris Sud, F-91405 Orsay (France); CNRS UMR 8080, F-91405 Orsay (France); Epigenomics Project, Genopole, Univ Evry Val d' Essonne, 91034 Evry Cedex (France); Tinevez, Jean-Yves [Laboratoire Physico-Chimie Curie, CNRS UMR 168, Institut Curie Recherche, 26, Rue d' Ulm, 75248 Paris Cedex 05 (France); Cloetens, Peter [European Synchrotron Radiation Facility, B.P. 220, F-38043 Grenoble (France); Schlenker, Michel [Institut Neel, CNRS, and Grenoble Institute of Technology, B.P. 166, F-38042 Grenoble (France)

    2009-03-15

    Unexpectedly severe radiation damage, showing up through deformation of the saccule, was encountered during a synchrotron radiation high-resolution (700 nm pixel size) tomographic observation of an inner ear, fixed in a formaldehyde solution, of the frog Rana esculenta. The visible displacement of the edge of the otoconia-filled part of the saccule amounted to about 100 {mu}m after an irradiation with 20.5 keV X-ray photons corresponding to a dose of 1.5 kGy for the protein matrix. The close-knit coexistence of organic and mineral components in the biological tissue may be linked to the dramatic increase of radiation dosage sensitivity.

  11. Reconstitution studies on the involvement of radiation-induced lipid peroxidation in damage to membrane enzymes.

    Science.gov (United States)

    Yukawa, O; Nagatsuka, S; Nakazawa, T

    1983-04-01

    The effect of radiation on the drug-metabolizing enzyme system of microsomes, reconstituted with liposomes of microsomal phospholipids, NADPH-cytochrome P-450 reductase and cytochrome P-450, was examined to elucidate the role of lipid peroxidation of membranes in radiation-induced damage to membrane-bound enzymes. The reconstituted system of non-irradiated enzymes with irradiated liposomes showed a low activity of hexobarbital hydroxylation, whereas irradiated enzymes combined with non-irradiated liposomes exhibited an activity equal to that of unirradiated controls. Irradiation of liposomes caused a decrease in cytochrome P-450 content by destruction of the haem of cytochrome P-450 and also inhibited the binding capacity of cytochrome P-450 for hexobarbital. The relationship between radiation-induced lipid peroxidation and membrane-bound enzymes is discussed.

  12. Reconstitution studies on the involvement of radiation-induced lipid peroxidation in damage to membrane enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Yukawa, O.; Nagatsuka, S.; Nakazawa, T. (National Inst. of Radiological Sciences, Chiba (Japan))

    1983-04-01

    The effect of ..gamma..-radiation on the drug-metabolizing enzyme system of microsomes, reconstituted with liposomes of microsomal phospholipids, NADPH-cytochrome P-450 reductase and cytochrome P-450, was examined to elucidate the role of lipid peroxidation of membranes in radiation-induced damage to membrane-bound enzymes. The reconstituted system of non-irradiated enzymes with irradiated liposomes showed a low activity of hexobarbital hydroxylation, whereas irradiated enzymes combined with non-irradiated liposomes exhibited an activity equal to that of unirradiated controls. Irradiation of liposomes caused a decrease in cytochrome P-450 content by destruction of the haem of cytochrome P-450 and also inhibited the binding capacity of cytochrome P-450 for hexobarbital. The relationship between radiation-induced lipid peroxidation and membrane-bound enzymes is discussed.

  13. Study on radiation damage to high energy accelerator components by irradiation in a nuclear reactor

    CERN Document Server

    Schönbacher, Helmut; Casta, J; Van de Voorde, M H

    1975-01-01

    The structural and other components used in high energy accelerators are continuously exposed to a wide spectrum of high energy particles and electromagnetic radiation. The resulting radiation damage may severely influence the functional capability of accelerator facilities. In order to arrive at an estimate of the service life of various materials in the radiation field, simulating experiments have to be carried out in a nuclear reactor. A large number of organic and inorganic materials, electronic components, metals, etc., intended specifically for use in 400 GeV proton synchrotron of CERN near Geneva, were irradiated in the ASTRA reactor in Seibersdorf near Vienna. The paper reports on the irradiation facilities available in this reactor for this purpose, on the dosimetry methods used, on the most important materials irradiated and on the results obtained in these experiments. (14 refs).

  14. Radiation Damage Mechanisms for Luminescence in Eu-doped GaN

    Energy Technology Data Exchange (ETDEWEB)

    Tringe, J W; Castelaz, J M; Felter, T E; Wetzel, C; Talley, C E; Morse, J D; Stevens, C G

    2005-11-01

    Thin films of Eu-doped GaN are irradiated with 500 keV He{sup +} ions to understand radiation damage mechanisms and to quantify luminescence efficiency. Ion beam induced luminescence was monitored spectroscopically as function of fluence. Behavior observed is consistent with simultaneous creation of non-radiative defects and destruction of luminescent centers associated with the 4f-4f core-level transition in Eu{sup 3+}. This model contrasts with a previous description which takes into account only non-radiative defect generation in GaN:Eu. Based on light from a BaF{sub 2} scintillator standard, the luminescent energy generation efficiency of GaN:Eu films doped to {approx}3 x 10{sup 18} cm{sup -3} Eu is estimated to be {approx}0.1%.

  15. THE ONE CINETIC MODEL DAMAGE OF CELL BY SMALL DOSES OF RADIATION

    Directory of Open Access Journals (Sweden)

    A. T. Gubin

    2015-01-01

    Full Text Available To explain the known differences in the dose and age dependences of radiogenic mortality from leukemia and solid tumors after single exposure, a model was developed, which is a modification of the Kellerer-Rossi theory of dual radiation action. The model assumes formation in a cell of both single and double primary damages due to radiation and other carcinogens, while the recovery rate of single damages (φ significantly exceeds that for double ones (ψ. Upon achieving a certain stage of the cell cycle (the critical age of cell – T, double damages become permanent and with probability of А can be inherited to daughter cells as “premalignant” defects. In contrast, in the Kellerer-Rossi theory, permanent damage is formed immediately after formation of the second damage at the next energy absorption event in the cell, i.e. ψ=0 .On the assumption that the premalignant defects only occur based on the double primary damages, i.e. φ>>ψ, the expressions for А were derived for the prompt radiation exposure and radiation exposure at a constant dose rate. They reproduce the effect increasing with decreasing of T, whereas the influence of T on the linear term of the dose expression in both cases is the same, but with decreasing of T the quadratic term increases faster for exposure at a constant dose rate than that for the prompt one. Thus, presence of the quadratic term in the dose expression for leukemia and its virtual complete absence for solid tumors may be due to lower T-value for hemopoietic stem cells. Predicted by the model dose rate influence on the quadratic term does not depend on the dose, so the reduction factor should be only applied to the quadratic term of the dose expression. This follows as well from the original version of the Kellerer-Rossi theory.

  16. Protection against radiation-induced damage of 6-propyl-2-thiouracil (PTU) in thyroid cells.

    Science.gov (United States)

    Perona, Marina; Dagrosa, María A; Pagotto, Romina; Casal, Mariana; Pignataro, Omar P; Pisarev, Mario A; Juvenal, Guillermo J

    2013-03-01

    Many epidemiologic studies have shown that the exposure to high external radiation doses increases thyroid neoplastic frequency, especially when given during childhood or adolescence. The use of radioprotective drugs may decrease the damage caused by radiation therapy and therefore could be useful to prevent the development of thyroid tumors. The aim of this study was to investigate the possible application of 6-propyl-2-thiouracil (PTU) as a radioprotector in the thyroid gland. Rat thyroid epithelial cells (FRTL-5) were exposed to different doses of γ irradiation with or without the addition of PTU, methimazole (MMI), reduced glutathione (GSH) and perchlorate (KClO4). Radiation response was analyzed by clonogenic survival assay. Cyclic AMP (cAMP) levels were measured by radioimmunoassay (RIA). Apoptosis was quantified by nuclear cell morphology and caspase 3 activity assays. Intracellular reactive oxygen species (ROS) levels were measured using the fluorescent dye 2',7'-dichlorofluorescein-diacetate. Catalase, superoxide dismutase and glutathione peroxidase activities were also determined. Pretreatment with PTU, MMI and GSH prior to irradiation significantly increased the surviving cell fraction (SF) at 2 Gy (P PTU treated cells in a dose and time-dependent manner. Cells incubated with agents that stimulate cAMP (forskolin and dibutyril cAMP) mimicked the effect of PTU on SF. Moreover, pretreatment with the inhibitor of protein kinase A, H-89, abolished the radioprotective effect of PTU. PTU treatment diminished radiation-induced apoptosis and protected cells against radiation-induced ROS elevation and suppression of the antioxidant enzyme's activity. PTU was found to radioprotect normal thyroid cells through cAMP elevation and reduction in both apoptosis and radiation-induced oxidative stress damage.

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

    Energy Technology Data Exchange (ETDEWEB)

    Costes, Sylvain V; Chiolo, Irene; Pluth, Janice M.; Barcellos-Hoff, Mary Helen; Jakob, Burkhard

    2009-09-15

    DNA damage sensing proteins have been shown to localize to the sites of 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 spatio-temporal properties of RIF at physiological doses, minutes to hours following exposure to ionizing radiation, and it proposes a model describing RIF formation and resolution as a function of radiation quality and nuclear densities. Discussion is limited to RIF formed by three interrelated proteins ATM (Ataxia telangiectasia mutated), 53BP1 (p53 binding protein 1) and ?H2AX (phosphorylated variant histone H2AX). Early post-IR, we propose that RIF mark chromatin reorganization, leading to a local nuclear scaffold rigid enough to keep broken DNA from diffusing away, but open enough to allow the repair machinery. We review data indicating clear kinetic and physical differences between RIF emerging from dense and uncondensed regions of the nucleus. At later time post-IR, we propose that persistent RIF observed days following exposure to ionizing radiation are nuclear ?scars? marking permanent disruption of the chromatin architecture. When DNA damage is resolved, such chromatin modifications should not necessarily lead to growth arrest and it has been shown that persistent RIF can replicate during mitosis. Thus, heritable persistent RIF spanning over tens of Mbp may affect the transcriptome of a large progeny of cells. This opens the door for a non DNA mutation-based mechanism of radiation-induced phenotypes.

  18. Mitochondrial tolerance to single and repeat exposure to simulated sunlight in human epidermal and dermal skin cells.

    Science.gov (United States)

    Kelly, J; Murphy, J E J

    2016-12-01

    Sunlight represents the primary threat to mitochondrial integrity in skin given the unique nature of the mitochondrial genome and its proximity to the electron transport chain. The accumulation of mitochondrial DNA (mtDNA) mutations is a key factor in many human pathologies and this is linked to key roles of mitochondrial function in terms of energy production and cell regulation. The main objective of this study was to evaluate solar radiation induced changes in mitochondrial integrity, function and dynamics in human skin cells using a Q-Sun solar simulator to deliver a close match to the intensity of summer sunlight. Spontaneously immortalised human skin epidermal keratinocytes (HaCaT) and Human Dermal Fibroblasts (HDFn) were divided into two groups. Group A were irradiated once and Group B twice 7days apart and evaluated using cell survival, viability and mitochondrial membrane potential (MMP) and mass at 1, 4 and 7days post one exposure for Group A and 1, 4, 7 and 14days post second exposure for Group B. Viability and survival of HaCaT and HDFn cells decreased after repeat exposure to Simulated Sunlight Irradiation (SSI) with no recovery. HDFn cells showed no loss in MMP after one or two exposures to SSI compared to HaCaT cells which showed a periodic loss of MMP after one exposure with a repeat exposure causing a dramatic decrease from which cells did not recover. Mitochondrial Mass in exposed HDFn cells was consistent with control after one or two exposures to SSI; however mitochondrial mass was significantly decreased in HaCaT cells. Data presented here suggests that mitochondria in epidermal cells are more sensitive to sunlight damage compared to mitochondria in dermal cells, despite their origin, confirming a skin layer specific sensitivity to sunlight, but not as expected. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Cytogenetic damage at low doses and the problem of bioindication of chronic low level radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Geras' kin, S.A.; Dikarev, V.G.; Nesterov, E.B.; Vasiliev, D.V.; Dikareva, N.S. [Russian Inst. of Agricultural Radiology and Agroecology, Obninsk (Russian Federation)

    2000-05-01

    The analysis undertaken by us of the experimentally observed cellular responses to low dose irradiation has shown that the relationship between the yield of induced cytogenetic damage and radiation dose within low dose range is non-linear and universal in character. Because of the relationship between the yield of cytogenetic damage and dose within low dose range is non-linear, the aberration frequency cannot be used in biological dosimetry in the most important in terms of practical application case. The cytogenetic damage frequency cannot be used in biological dosimetry also because of the probability of synergistic and antagonistic interaction effects of the different nature factors simultaneously acting on test-object in real conditions is high within low dose (concentration) range. In our experimental study of the regularities in the yield of structural mutations in conditions of combined influence of ionizing radiation, heavy metals and pesticides it was found that synergistic and antagonistic effects are mainly induced in conditions of combined action of low exposure injuring agents. Experiments on agricultural plants were carried out in 1986-1989 at the 30-km zone around Chernobyl NPP. It was shown that chronic low dose exposure could cause an inheritable destabilization of genetic structures expressing in increase of cytogenetic damage and yield karyotypic variability in offspring's of irradiated organisms. Obviously exactly this circumstance is the reason of the phenomenon found in our researches of significant time delay of cytogenetic damage reduction rate from radioactive pollution reduction rate from time past from the accident moment. Research of cytogenetic damage of reproductive (seeds) and vegetative (needles) plant organs of the Pinus sylvestris tree micropopulations growing in contrast by radioactive pollution level sites of the 30-km ChNPP zone and also in the vicinity of the industrial plant <> for processing and temporary storage

  20. The pristine atomic structure of MoS{sub 2} monolayer protected from electron radiation damage by graphene

    Energy Technology Data Exchange (ETDEWEB)

    Algara-Siller, Gerardo; Kurasch, Simon; Sedighi, Mona; Lehtinen, Ossi; Kaiser, Ute [Central Facility for Electron Microscopy, Group of Electron Microscopy of Materials Science, Ulm University (Germany)

    2013-11-11

    Materials can, in principle, be imaged at the level of individual atoms with aberration-corrected transmission electron microscopy. However, such resolution can be attained only with very high electron doses. Consequently, radiation damage is often the limiting factor when characterizing sensitive materials. Here, we demonstrate a simple and an effective method to increase the electron radiation tolerance of materials by using graphene as protective coating. This leads to an improvement of three orders of magnitude in the radiation tolerance of monolayer MoS{sub 2}. Further on, we construct samples in different heterostructure configurations to separate the contributions of different radiation damage mechanisms.

  1. The pristine atomic structure of MoS2 monolayer protected from electron radiation damage by graphene

    Science.gov (United States)

    Algara-Siller, Gerardo; Kurasch, Simon; Sedighi, Mona; Lehtinen, Ossi; Kaiser, Ute

    2013-11-01

    Materials can, in principle, be imaged at the level of individual atoms with aberration-corrected transmission electron microscopy. However, such resolution can be attained only with very high electron doses. Consequently, radiation damage is often the limiting factor when characterizing sensitive materials. Here, we demonstrate a simple and an effective method to increase the electron radiation tolerance of materials by using graphene as protective coating. This leads to an improvement of three orders of magnitude in the radiation tolerance of monolayer MoS2. Further on, we construct samples in different heterostructure configurations to separate the contributions of different radiation damage mechanisms.

  2. Spectrum of Radiation-Induced Clustered Non-DSB Damage - A Monte Carlo Track Structure Modeling and Calculations.

    Science.gov (United States)

    Watanabe, Ritsuko; Rahmanian, Shirin; Nikjoo, Hooshang

    2015-05-01

    The aim of this report is to present the spectrum of initial radiation-induced cellular DNA damage [with particular focus on non-double-strand break (DSB) damage] generated by computer simulations. The radiation types modeled in this study were monoenergetic electrons (100 eV-1.5 keV), ultrasoft X-ray photons Ck, AlK and TiK, as well as some selected ions including 3.2 MeV/u proton; 0.74 and 2.4 MeV/u helium ions; 29 MeV/u nitrogen ions and 950 MeV/u iron ions. Monte Carlo track structure methods were used to simulate damage induction by these radiation types in a cell-mimetic condition from a single-track action. The simulations took into account the action of direct energy deposition events and the reaction of hydroxyl radicals on atomistic linear B-DNA segments of a few helical turns including the water of hydration. Our results permitted the following conclusions: a. The absolute levels of different types of damage [base damage, simple and complex single-strand breaks (SSBs) and DSBs] vary depending on the radiation type; b. Within each damage class, the relative proportions of simple and complex damage vary with radiation type, the latter being higher with high-LET radiations; c. Overall, for both low- and high-LET radiations, the ratios of the yields of base damage to SSBs are similar, being about 3.0 ± 0.2; d. Base damage contributes more to the complexity of both SSBs and DSBs, than additional SSB damage and this is true for both low- and high-LET radiations; and e. The average SSB/DSB ratio for low-LET radiations is about 18, which is about 5 times higher than that for high-LET radiations. The hypothesis that clustered DNA damage is more difficult for cells to repair has gained currency among radiobiologists. However, as yet, there is no direct in vivo experimental method to validate the dependence of kinetics of DNA repair on DNA damage complexity (both DSB and non-DSB types). The data on the detailed spectrum of DNA damage presented here, in particular

  3. In vivo and in vitro evaluation of corneal damage induced by 1573 nm laser radiation

    Energy Technology Data Exchange (ETDEWEB)

    Courant, D.; Chapel, C. [CEA Fontenay-aux-Roses (DSV/DRR/SRBF), 92 (France). Dept. de Radiobiologie et de Radiopathologie; Pothier, C. [DGA-DCE/CTA/LOT, 94 - Arcueil (France); Sales, N. [CEA Fontenay-aux-Roses (DSV/DRM/SNV), 92 (France)

    2006-07-01

    Recent developments in laser technology have originated a variety of infrared laser sources between 1500-1700 nm called as 'eye-safe' which are gaining widespread use in industry, medicine and military applications. This spectral region has been called 'eye safe' because the cornea and aqueous humor absorb sufficient radiation to prevent nearly all potentially damaging radiation from reaching the retina whereas the lens does not absorb this spectral range and remains undamaged. However, in providing protection for the deeper layers of the eye, the cornea itself is susceptible to thermal damage. Previous studies, performed at 1540 nm with exposures less than 1 s, are inconsistent in the quantity of energy required to cause corneal damage. The purpose of this study was first, to determine the threshold damage exposure (E.D.{sub 50}) on rabbit cornea induced by a 3 ns single pulse emitted at 1573 nm, using clinical observations and histology and to compare the results to the limit values recommended by I.C.N.I.R.P. guidelines or international standards. Secondly, it was suggested to investigate the cellular effects of infrared radiation with biochemical techniques on cell cultures in order to specify a cellular damage threshold and a better understanding of the laser - tissue interaction and the corneal injury. The minimal damage criterion was defined by a shallow, very small depression of the epithelial surface with a mild fluorescein staining. The E.D.{sub 50} obtained with corneal beam diameter of 400 mm is 26.6 J.cm{sup -2}. The corresponding radiant exposure, calculated with the 1 mm aperture diameter recommended by I.C.N.I.R.P. guidelines or standards, is 4.3 J.cm{sup -2}. In vitro experiments have been carried out on primary keratocytes and H.T. 1080 epithelial cell line, using an expanded beam of 3.5 mm diameter on plates or Lab Tek holders. Cells were irradiated with 10 Hz pulse ratio frequency during 1, 2 or 3 s. The S A

  4. Detection of DNA damage by space radiation in human fibroblasts flown on the International Space Station.

    Science.gov (United States)

    Lu, Tao; Zhang, Ye; Wong, Michael; Feiveson, Alan; Gaza, Ramona; Stoffle, Nicholas; Wang, Huichen; Wilson, Bobby; Rohde, Larry; Stodieck, Louis; Karouia, Fathi; Wu, Honglu

    2017-02-01

    Although charged particles in space have been detected with radiation detectors on board spacecraft since the discovery of the Van Allen Belts, reports on the effects of direct exposure to space radiation in biological systems have been limited. Measurement of biological effects of space radiation is challenging due to the low dose and low dose rate nature of the radiation environment, and due to the difficulty in distinguishing the radiation effects from microgravity and other space environmental factors. In astronauts, only a few changes, such as increased chromosome aberrations in their lymphocytes and early onset of cataracts, are attributed primarily to their exposure to space radiation. In this study, cultured human fibroblasts were flown on the International Space Station (ISS). Cells were kept at 37°C in space for 14 days before being fixed for analysis of DNA damage with the γ-H2AX assay. The 3-dimensional γ-H2AX foci were captured with a laser confocal microscope. Quantitative analysis revealed several foci that were larger and displayed a track pattern only in the Day 14 flight samples. To confirm that the foci data from the flight study was actually induced from space radiation exposure, cultured human fibroblasts were exposed to low dose rate γ rays at 37°C. Cells exposed to chronic γ rays showed similar foci size distribution in comparison to the non-exposed controls. The cells were also exposed to low- and high-LET protons, and high-LET Fe ions on the ground. Our results suggest that in G1 human fibroblasts under the normal culture condition, only a small fraction of large size foci can be attributed to high-LET radiation in space.

  5. Detection of DNA damage by space radiation in human fibroblasts flown on the International Space Station

    Science.gov (United States)

    Lu, Tao; Zhang, Ye; Wong, Michael; Feiveson, Alan; Gaza, Ramona; Stoffle, Nicholas; Wang, Huichen; Wilson, Bobby; Rohde, Larry; Stodieck, Louis; Karouia, Fathi; Wu, Honglu

    2017-02-01

    Although charged particles in space have been detected with radiation detectors on board spacecraft since the discovery of the Van Allen Belts, reports on the effects of direct exposure to space radiation in biological systems have been limited. Measurement of biological effects of space radiation is challenging due to the low dose and low dose rate nature of the radiation environment, and due to the difficulty in distinguishing the radiation effects from microgravity and other space environmental factors. In astronauts, only a few changes, such as increased chromosome aberrations in their lymphocytes and early onset of cataracts, are attributed primarily to their exposure to space radiation. In this study, cultured human fibroblasts were flown on the International Space Station (ISS). Cells were kept at 37 °C in space for 14 days before being fixed for analysis of DNA damage with the γ-H2AX assay. The 3-dimensional γ-H2AX foci were captured with a laser confocal microscope. Quantitative analysis revealed several foci that were larger and displayed a track pattern only in the Day 14 flight samples. To confirm that the foci data from the flight study was actually induced from space radiation exposure, cultured human fibroblasts were exposed to low dose rate γ rays at 37 °C. Cells exposed to chronic γ rays showed similar foci size distribution in comparison to the non-exposed controls. The cells were also exposed to low- and high-LET protons, and high-LET Fe ions on the ground. Our results suggest that in G1 human fibroblasts under the normal culture condition, only a small fraction of large size foci can be attributed to high-LET radiation in space.

  6. The radioprotective effect and mechanism of captopril on radiation induced-heart damage in rats

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Seung Hee; Lee, Kyung Ja; Koo, Hea Soo [Ewha Womans University, Seoul (Korea, Republic of)

    2004-03-15

    group at 2 weeks. At 8 weeks, the expressions of TNF- {alpha} in the atrial and ventricular pericardia were markedly reduced ({rho} = 0.049, {rho} = 0.009). The study revealed that the early heart damage induced by radiation can be reduced by the addition of captopril in a rat model. The expressions of TNF- {alpha} , TGF- {beta} 1, and PDGF were further decreased in the combined compared to the radiation alone group at both 2 and 8 weeks. From these results, it may be concluded that these cytokines probably play roles in the radioprotective mechanism of captopril from the radiation-induced heart toxicity, similarly to in other organs.

  7. Influence of complex impurity centres on radiation damage in wide-gap metal oxides

    Energy Technology Data Exchange (ETDEWEB)

    Lushchik, A., E-mail: aleksandr.lushchik@ut.ee [Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu (Estonia); Lushchik, Ch. [Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu (Estonia); Popov, A.I. [Institute of Solid State Physics, University of Latvia, Kengaraga 8, Riga LV-1063 (Latvia); Schwartz, K. [GSI Helmholtzzentrum für Schwerionenforschung (GSI), Planckstr. 1, 64291 Darmstadt (Germany); Shablonin, E.; Vasil’chenko, E. [Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu (Estonia)

    2016-05-01

    Different mechanisms of radiation damage of wide-gap metal oxides as well as a dual influence of impurity ions on the efficiency of radiation damage have been considered on the example of binary ionic MgO and complex ionic–covalent Lu{sub 3}Al{sub 5}O{sub 12} single crystals. Particular emphasis has been placed on irradiation with ∼2 GeV heavy ions ({sup 197}Au, {sup 209}Bi, {sup 238}U, fluence of 10{sup 12} ions/cm{sup 2}) providing extremely high density of electronic excitations within ion tracks. Besides knock-out mechanism for Frenkel pair formation, the additional mechanism through the collapse of mobile discrete breathers at certain lattice places (e.g., complex impurity centres) leads to the creation of complex defects that involve a large number of host atoms. The experimental manifestations of the radiation creation of intrinsic and impurity antisite defects (Lu|{sub Al} or Ce|{sub Al} – a heavy ion in a wrong cation site) have been detected in LuAG and LuAG:Ce{sup 3+} single crystals. Light doping of LuAG causes a small enhancement of radiation resistance, while pair impurity centres (for instance, Ce|{sub Lu}–Ce|{sub Al} or Cr{sup 3+}–Cr{sup 3+} in MgO) are formed with a rise of impurity concentration. These complex impurity centres as well as radiation-induced intrinsic antisite defects (Lu|{sub Al} strongly interacting with Lu in a regular site) tentatively serve as the places for breathers collapse, thus decreasing the material resistance against dense irradiation.

  8. Space Radiation Induced Cytogenetic Damage in the Blood Lymphocytes of Astronauts

    Science.gov (United States)

    George, K.; Cucinotta, F. A.

    2008-01-01

    Cytogenetic analysis of astronauts blood lymphocytes provides a direct in vivo measurement of space radiation damage, which takes into account individual radiosensitivity and considers the influence of microgravity and other stress conditions. We present our latest analyses of chromosome damage in astronauts blood lymphocytes assessed by fluorescence in situ hybridization (FISH) chromosome painting and collected at various times beginning directly after return from space to several years after flight. Dose was derived from frequencies of chromosome exchanges using preflight calibration curves, and the Relative Biological Effect (RBE) was estimated by comparison with individually measured physically absorbed doses. Values for average RBE were compared to the average quality factor (Q), from direct measurements of the lineal energy spectra using a tissue-equivalent proportional counter (TEPC) and radiation transport codes. Results prove that cytogenetic biodosimetry analyses on blood collected within a week or two of return from space provides a reliable estimate of equivalent radiation dose and risk after protracted exposure to space radiation of a few months or more. However, data collected several months or years after flight suggests that the yield of chromosome translocations may decline with time after the mission, indicating that retrospective doses may be more difficult to estimate. In addition, limited data on multiple flights show a lack of correlation between time in space and translocation yields. Data from one crewmember, who has participated in two separate long-duration space missions and has been followed up for over 10 years, provide limited information on the effect of repeat flights and show a possible adaptive response to space radiation exposure.

  9. Automated analysis of damages for radiation in plastics surfaces; Analisis automatizado de danos por radiacion en superficies plasticas

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, C.; Camacho M, E.; Tavera, L.; Balcazar, M. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    1990-02-15

    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)

  10. Hepatocyte growth factor gene therapy prevents radiation-induced liver damage

    Institute of Scientific and Technical Information of China (English)

    Chau-Hua Chi; I-Li Liu; Wei-Yu Lo; Bor-Song Liaw; Yu-Shan Wang; Kwan-Hwa Chi

    2005-01-01

    AIM: To transfer human HGF gene into the liver of rats by direct electroporation as a means to prevent radiationinduced liver damage.METHODS: Rat whole liver irradiation model was accomplished by intra-operative approach. HGF plasmid was injected into liver and transferred by electroporation using a pulse generator. Control rats (n = 8) received electrogene therapy (EGT) vehicle plasmid and another 8rats received HGF-EGT 100 μg 48 h before WLIR.Expression of HGF in liver was examined by RT-PCR and ELISA methods. Apoptosis was determined by TUNEL assay. Histopathology was evaluated 10 wk after whole liver irradiation.RESULTS: Marked decrease of apoptotic cells and downregulation of transforming growth factor-beta 1 (TGF-β1)mRNA were observed in the HGF-EGT group 2 d after liver irradiation compared to control animals. Less evidence of radiation-induced liver damage was observed morphologically in liver specimen 10 wk after liver irradiation and longer median survival time was observed from HGF-EGT group (14 wk) compared to control rats (5 wk). (P = 0.031).CONCLUSION: For the first time it has been demonstrated that HGF-EGT would prevent liver from radiation-induced liver damage by preventing apoptosis and down-regulation of TGF-β1.

  11. Study the radiation damage effects in Si microstrip detectors for future HEP experiments

    Science.gov (United States)

    Lalwani, Kavita; Jain, Geetika; Dalal, Ranjeet; Ranjan, Kirti; Bhardwaj, Ashutosh

    2016-07-01

    Silicon (Si) detectors are playing a key role in High Energy Physics (HEP) experiments due to their superior tracking capabilities. In future HEP experiments, like upgrade of the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC), CERN, the silicon tracking detectors will be operated in a very intense radiation environment. This leads to both surface and bulk damage in Si detectors, which in turn will affect the operating performance of Si detectors. It is important to complement the measurements of the irradiated Si strip detectors with device simulation, which helps in understanding of both the device behavior and optimizing the design parameters needed for the future Si tracking system. An important ingredient of the device simulation is to develop a radiation damage model incorporating both bulk and surface damage. In this work, a simplified two-trap model is incorporated in device simulation to describe the type-inversion. Further, an extensive simulation of effective doping density as well as electric field profile is carried out at different temperatures for various fluences.

  12. Experiments testing the abatement of radiation damage in D-xylose isomerase crystals with cryogenic helium.

    Science.gov (United States)

    Hanson, B Leif; Harp, Joel M; Kirschbaum, Kristin; Schall, Constance A; DeWitt, Ken; Howard, Andrew; Pinkerton, A Alan; Bunick, Gerard J

    2002-11-01

    Helium is a more efficient cryogen than nitrogen, and for macromolecular data collection at high-flux beamlines will deliver lower temperatures. An open-flow helium cryostat developed at the University of Toledo (the Pinkerton Device) has been used for macromolecular data collection. This device differs from standard commercial He cryostats by having a much narrower aperture providing a high velocity stream of He around the crystal that maximizes convective and conductive heat exchange between the crystal and the cryogen. This paper details a series of experiments conducted at the IMCA-CAT 17ID beamline using one crystal for each experimental condition to examine whether helium at 16 K provided better radiation-damage abatement compared with nitrogen at 100 K. These studies used matched high-quality crystals (0.94 A diffraction resolution) of D-xylose isomerase derived from the commercial material Gensweet SGI. Comparisons show that helium indeed abates the indicators of radiation damage, in this case resulting in longer crystal diffractive lifetimes. The overall trend suggests that crystals maintain order and that high-resolution data are less affected by increased radiation load when crystals are cooled with He rather than N(2). This is probably the result of a lower effective temperature at the crystal with concomitant reduction in free-radical diffusion. Other features, such as an apparent phase transition in macromolecular crystals at lower temperatures, require investigation to broaden the utility of He use.

  13. A Review on Radiation Damage in Concrete for Nuclear Facilities: From Experiments to Modeling

    Directory of Open Access Journals (Sweden)

    Beatrice Pomaro

    2016-01-01

    Full Text Available Concrete is a relatively cheap material and easy to be cast into variously shaped structures. Its good shielding properties against neutrons and gamma-rays, due to its intrinsic water content and relatively high-density, respectively, make it the most widely used material for radiation shielding also. Concrete is so chosen as biological barrier in nuclear reactors and other nuclear facilities where neutron sources are hosted. Theoretical formulas are available in nuclear engineering manuals for the optimum thickness of shielding for radioprotection purposes; however they are restricted to one-dimensional problems; besides the basic empirical constants do not consider radiation damage effects, while its long-term performance is crucial for the safe operation of such facilities. To understand the behaviour of concrete properties, it is necessary to examine concrete strength and stiffness, water behavior, volume change of cement paste, and aggregate under irradiated conditions. Radiation damage process is not well understood yet and there is not a unified approach to the practical and predictive assessment of irradiated concrete, which combines both physics and structural mechanics issues. This paper provides a collection of the most distinguished contributions on this topic in the past 50 years. At present a remarkable renewed interest in the subject is shown.

  14. DNA Damage in Melania Snail (Semisulcospira libertine) Irradiated with Gamma Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Tae Ho; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Advanced Radiation Technology Institute, Jeongeup (Korea, Republic of); An, Kwang Guk [Chungnam National University, Daejeon (Korea, Republic of); Nili, Mohammad [Dawnesh Radiation Research Institute, Barcelona (Spain)

    2010-10-15

    Generally radiological protection has focused on human. But International Commission on Radiological Protection (ICRP) requires the effect data of ionizing radiation on nonhuman biota for the radiological protection of the environment. The choice of a melania snail as a model for environmental biomonitoring of radiation genotoxicity took into account that invertebrates represent one of aquatic species. The comet assay or single cell gel electrophoresis (SCGE) assay, first introduced by Ostling and Johanson, was used to detect DNA single strand breaks and to investigate the application of this technique as a tool for aquatic biomonitoring. Comet assay offers considerable advantages over some other assays used in DNA damage detection, such as chromosomal aberrations, sister chromatid Exchange and the micronucleus test, since there is no need for cells to be in a dividing state. Other advantages are its rapidity, relatively low coast, and wide applicability to virtually any nucleated cell type. In this study, we evaluated DNA damage in cells of Semisulcospira libertina after irradiation with {sup 60}Co gamma radiation by using the comet assay

  15. Radiation damage of the PCO Pixelfly VGA CCD camera of the BES system on KSTAR tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Náfrádi, Gábor, E-mail: nafradi@reak.bme.hu [NTI, BME, EURATOM Association, H-1111 Budapest (Hungary); Kovácsik, Ákos, E-mail: kovacsik.akos@reak.bme.hu [NTI, BME, EURATOM Association, H-1111 Budapest (Hungary); Pór, Gábor, E-mail: por@reak.bme.hu [NTI, BME, EURATOM Association, H-1111 Budapest (Hungary); Lampert, Máté, E-mail: lampert.mate@wigner.mta.hu [Wigner RCP, RMI, EURATOM Association, POB 49, 1525 Budapest (Hungary); Un Nam, Yong, E-mail: yunam@nfri.re.kr [NFRI, 169-148 Gwahak-Ro, Yuseong-Gu, Daejeon 305-806 (Korea, Republic of); Zoletnik, Sándor, E-mail: zoletnik.sandor@wigner.mta.hu [Wigner RCP, RMI, EURATOM Association, POB 49, 1525 Budapest (Hungary)

    2015-01-11

    A PCO Pixelfly VGA CCD camera which is part a of the Beam Emission Spectroscopy (BES) diagnostic system of the Korea Superconducting Tokamak Advanced Research (KSTAR) used for spatial calibrations, suffered from serious radiation damage, white pixel defects have been generated in it. The main goal of this work was to identify the origin of the radiation damage and to give solutions to avoid it. Monte Carlo N-Particle eXtended (MCNPX) model was built using Monte Carlo Modeling Interface Program (MCAM) and calculations were carried out to predict the neutron and gamma-ray fields in the camera position. Besides the MCNPX calculations pure gamma-ray irradiations of the CCD camera were carried out in the Training Reactor of BME. Before, during and after the irradiations numerous frames were taken with the camera with 5 s long exposure times. The evaluation of these frames showed that with the applied high gamma-ray dose (1.7 Gy) and dose rate levels (up to 2 Gy/h) the number of the white pixels did not increase. We have found that the origin of the white pixel generation was the neutron-induced thermal hopping of the electrons which means that in the future only neutron shielding is necessary around the CCD camera. Another solution could be to replace the CCD camera with a more radiation tolerant one for example with a suitable CMOS camera or apply both solutions simultaneously.

  16. Radiation damage of the PCO Pixelfly VGA CCD camera of the BES system on KSTAR tokamak

    Science.gov (United States)

    Náfrádi, Gábor; Kovácsik, Ákos; Pór, Gábor; Lampert, Máté; Un Nam, Yong; Zoletnik, Sándor

    2015-01-01

    A PCO Pixelfly VGA CCD camera which is part a of the Beam Emission Spectroscopy (BES) diagnostic system of the Korea Superconducting Tokamak Advanced Research (KSTAR) used for spatial calibrations, suffered from serious radiation damage, white pixel defects have been generated in it. The main goal of this work was to identify the origin of the radiation damage and to give solutions to avoid it. Monte Carlo N-Particle eXtended (MCNPX) model was built using Monte Carlo Modeling Interface Program (MCAM) and calculations were carried out to predict the neutron and gamma-ray fields in the camera position. Besides the MCNPX calculations pure gamma-ray irradiations of the CCD camera were carried out in the Training Reactor of BME. Before, during and after the irradiations numerous frames were taken with the camera with 5 s long exposure times. The evaluation of these frames showed that with the applied high gamma-ray dose (1.7 Gy) and dose rate levels (up to 2 Gy/h) the number of the white pixels did not increase. We have found that the origin of the white pixel generation was the neutron-induced thermal hopping of the electrons which means that in the future only neutron shielding is necessary around the CCD camera. Another solution could be to replace the CCD camera with a more radiation tolerant one for example with a suitable CMOS camera or apply both solutions simultaneously.

  17. Contributions of each isotope in structural material on radiation damage in a hybrid reactor

    Science.gov (United States)

    Günay, Mehtap

    2016-11-01

    In this study, the fluids were used in the liquid first-wall, blanket and shield zones of the designed hybrid reactor system. In this study, salt-heavy metal mixtures consisting of 93-85% Li20Sn80 + 5% SFG-PuO2 and 2-10% UO2, 93-85% Li20Sn80 + 5% SFG-PuO2 and 2-10% NpO2, and 93-85% Li20Sn80 + 5% SFG-PuO2 and 2-10% UCO were used as fluids. In this study, the effect on the radiation damage of spent fuel-grade (SFG)-PuO2, UO2, NpO2 and UCO contents was investigated in the structural material of a designed fusion-fission hybrid reactor system. In the designed hybrid reactor system were investigated the effect on the radiation damage of the selected fluid according to each isotopes of structural material in the structural material for 30 full power years (FPYs). Three-dimensional analyses were performed using the most recent MCNPX-2.7.0 Monte Carlo radiation transport code and the ENDF/B-VII.0 nuclear data library.

  18. Stability of Bacillus thuringiensis and NPV Microencapsulated Formulation under Sunlight

    Directory of Open Access Journals (Sweden)

    Samaneh Sadat Naghavi

    2016-06-01

    Full Text Available Microencapsulation technology is used for the formulation of bio pesticides and is effective against the ultra-violet radiation of sunlight. The present research studied the stability of Bt and NPV formulations microencapsulated with gelatin and sodium alginate, individually or in combination. The formulations were evaluated in outdoor space and under sunlight on potted growing cabbage. The stability of each active ingredient tested in each formulation was studied at 0, 3, 7 and 10 days after spraying on cabbage infested with diamondback moth Plutella xylostella second instars larvae. Results showed that non-formulated and microencapsulated formulations not exposed to sunlight (time zero had similar mortality. However, after being exposed to sunlight for three days, the non-formulated Bt and NPV resulted in a significantly lower mortality (less than 40%; compared with the microencapsulated bio pesticides (more than 70% mortality. Fifty percent (50% mortality was reached in microencapsulated formulations after seven and ten days of exposure to sunlight, whereas there was no mortality in larvae exposed to unformulated treated plants after ten days. ANOVA analysis showed the highest larval mortality was achieved by the Bt+NPV gelatin microencapsulated formulation followed by gelatin coated Bt, sodium alginate coated NPV, sodium alginate coated Bt+NPV, gelatin coated NPV and sodium alginate coated Bt. The formulations showed no significant LT50 differences between microencapsulated versus unformulated Bt and NPV.

  19. Early to late sparing of radiation damage to the parotid gland by adrenergic and muscarinic receptor agonists

    NARCIS (Netherlands)

    Coppes, RP; Zeilstra, LJW; Kampinga, HH; Konings, AWT

    2001-01-01

    Damage to salivary glands after radiotherapeutic treatment of head and neck tumours can severely impair the quality of life of the patients. In the current study we have investigated the early-to-late pathogenesis of the parotid gland after radiation. Also the ability to ameliorate the damage using

  20. Transgenerational accumulation of radiation damage in small mammals chronically exposed to Chernobyl fallout.

    Science.gov (United States)

    Ryabokon, Nadezhda I; Goncharova, R I

    2006-09-01

    The purpose of this investigation has been the analysis of the long-term development of biological damage in natural populations of a model mammalian species, the bank vole (Clethrionomys glareolus, Schreber), which were chronically exposed to low doses of ionizing radiation over 22 animal generations within 10 years following the Chernobyl accident. The time course of the biological end-points (chromosome aberrations in bone marrow cells and embryonic lethality) was compared with the time course of the whole-body absorbed dose rate from external and internal exposure in the studied populations inhabiting monitoring sites in Belarus with different ground deposition of radionuclides. The yield of chromosome aberrations and, in lesser degree, embryonic lethality was associated with the radionuclide contamination of the monitoring areas in a dose-dependent manner. As a main feature of the long-term development of biological damage under low dose rate irradiation, permanently elevated levels of chromosome aberrations and an increasing frequency of embryonic lethality have developed over 22 animal generations. This contrasts with the assumption that the biological damage would gradually disappear since in the same period of time the whole-body absorbed dose rate decreased exponentially with a half-value time of about 2.5-3 years. Furthermore, gravid females were captured, and their offspring, born and grown up under contamination-free laboratory conditions, showed the same enhanced level of chromosome aberrations. Therefore the authors suggest that, along with the biological damage attributable to the individual exposure of each animal, the observed cellular and systemic effects reflect the transgenerational transmission and accumulation, via genetic and/or epigenetic pathways, of damage attributable to the chronic low-dose rate exposure of the preceding generations of animals. They also suggest that the level of the accumulated transmissible damage in the investigated

  1. The radioprotective effect and mechanism of captopril on radiation induced lung damage in rat

    Energy Technology Data Exchange (ETDEWEB)

    Song, Mi Hee; Lee, Kyung Ja; Koo, Hea Soo; Oh, Won Young [College of Medicine, Ewha Women Univ., Seoul (Korea, Republic of)

    2001-06-01

    It was reported that Captopril (angiotensin converting enzyme inhibitor) had an effect to reduce the pneumonitis and pulmonary fibrosis induced by radiation in rat. We performed this study to investigate the radioprotective effect and mechanism of Captopril. The comparison was made between the radiation only group and the combined Captopril and radiation group by examining histopathologic findings and immunohistochemical stains (TNF {alpha} and TGF {beta}1) at 2 and 8 weeks after irradiation. Each group has 8 to 10 rats (Sprague-Dawley). 12.5 Gy of X-ray was irradiated to the left hemithorax in a single fraction. Captopril (50 mg/kg/d) mixed with water was given per oral and continuously from 1 week prior to irradiation up to 8th week of the experiment. In the combined Captopril and radiation group, the histopathologic changes which were hemorrhage into alveolar space, changes of alveolar epithelium, bronchial epithelium and blood vessels, and perivascular edema were less severe than in the radiation only group at 2 weeks. At 8 weeks, the alveolar epithelial changes and perivascular edema were less prominent in the combined Captopril and radiation group. At 2 weeks, the TNF {alpha} expression of the combined Captopril and radiation group was markedly decreased at the alveolar epithelium (p<0.01), lymphoid tissue (p=0.06) and the macrophage of alveolar space (p<0.01) compared with the radiation only group. Furthermore the TGF {beta}1 expression was significantly prominent at the alveolar epithelium (p<0.02) and the macrophage in alveolar space (p< 0.02). At 8 weeks, the expression of TNF {alpha} and TGF {beta} 1 of most sites, except TGF {beta}1 of the macrophage of alveolar space (p=0.09), showed no significant difference between 2 groups. This study revealed that early lung damage induced by irradiation was reduced with the addition of Captopril in the latent and early pneumonitis phase. The expression of TNF {alpha} and TGF {beta} 1 at 2 weeks and TGF {beta} 1 at

  2. Detection of DNA Damage by Space Radiation in Human Fibroblasts Flown on the International Space Station

    Science.gov (United States)

    Lu, Tao; Zhang, Ye; Wong, Michael; Feiveson, Alan; Gaza, Ramona; Stoffle, Nicholas; Wang, Huichen; Wilson, Bobby; Rohde, Larry; Stodieck, Louis; hide

    2017-01-01

    Space radiation consists of energetic charged particles of varying charges and energies. Exposure of astronauts to space radiation on future long duration missions to Mars, or missions back to the Moon, is expected to result in deleterious consequences such as cancer and comprised central nervous system (CNS) functions. Space radiation can also cause mutation in microorganisms, and potentially influence the evolution of life in space. Measurement of the space radiation environment has been conducted since the very beginning of the space program. Compared to the quantification of the space radiation environment using physical detectors, reports on the direct measurement of biological consequences of space radiation exposure have been limited, due primarily to the low dose and low dose rate nature of the environment. Most of the biological assays fail to detect the radiation effects at acute doses that are lower than 5 centiSieverts. In a recent study, we flew cultured confluent human fibroblasts in mostly G1 phase of the cell cycle to the International Space Station (ISS). The cells were fixed in space after arriving on the ISS for 3 and 14 days, respectively. The fixed cells were later returned to the ground and subsequently stained with the gamma-H2AX (Histone family, member X) antibody that are commonly used as a marker for DNA damage, particularly DNA double strand breaks, induced by both low-and high-linear energy transfer radiation. In our present study, the gamma-H2AX (Histone family, member X) foci were captured with a laser confocal microscope. To confirm that some large track-like foci were from space radiation exposure, we also exposed, on the ground, the same type of cells to both low-and high-linear energy transfer protons, and high-linear energy transfer Fe ions. In addition, we exposed the cells to low dose rate gamma rays, in order to rule out the possibility that the large track-like foci can be induced by chronic low-linear energy transfer

  3. Investigation on the use of Americium Oxide for Space Power Sources: Radiation Damage Studies

    Directory of Open Access Journals (Sweden)

    Wiss T.

    2017-01-01

    Several candidate Americium compounds will be investigated for chemical stability at high temperature and for self-irradiation damage. New thermo-electric converter materials containing actinides will be assessed, and a robust encapsulation designed. Safety analyses will be performed including launch explosion and re-entry accidents. The research will conclude in a conceptual design of a prototype power source. In the first part of this study, americium dioxide will be considered from the point of view of its chemical durability and of its behavior against radiation damage and helium formation, two aspects to be carefully investigated due to the high alpha-activity of the americium. Transmission electron Microscopy (TEM and helium thermal desorption spectrometry (TDS experiments will be described and results on aged (more than 30 years AmO2 reported. Some comparison with 238PuO2 based RTG’s will be discussed.

  4. Fast heavy-ion radiation damage of glycine in aqueous solution

    Science.gov (United States)

    Nomura, Shinji; Tsuchida, Hidetsugu; Furuya, Ryosuke; Majima, Takuya; Itoh, Akio

    2016-12-01

    Fast heavy-ion radiolysis of biomolecules in aqueous solution is investigated for an atomistic understanding of radiation damage to normal cells during heavy-particle beam therapy. The smallest amino acid glycine was used as a model biomaterial. Microjets of aqueous glycine solutions under vacuum were irradiated with 4.0-MeV carbon ions corresponding to energies in the Bragg peak region. To understand the effects of the water environment on molecular damage, the yield of glycine dissociation was measured by secondary ion mass spectroscopy. The yield was significantly reduced relative to gas-phase glycine targets. This implies that the numerous water molecules surrounding a single glycine molecule act as a buffer that suppresses dissociation. This is an environmental effect similar to that observed for other biomolecular cluster targets.

  5. Modelling electron distributions within ESA's Gaia satellite CCD pixels to mitigate radiation damage

    CERN Document Server

    Seabroke, G M; Burt, D; Robbins, M S

    2009-01-01

    The Gaia satellite is a high-precision astrometry, photometry and spectroscopic ESA cornerstone mission, currently scheduled for launch in 2012. Its primary science drivers are the composition, formation and evolution of the Galaxy. Gaia will achieve its unprecedented positional accuracy requirements with detailed calibration and correction for radiation damage. At L2, protons cause displacement damage in the silicon of CCDs. The resulting traps capture and emit electrons from passing charge packets in the CCD pixel, distorting the image PSF and biasing its centroid. Microscopic models of Gaia's CCDs are being developed to simulate this effect. The key to calculating the probability of an electron being captured by a trap is the 3D electron density within each CCD pixel. However, this has not been physically modelled for the Gaia CCD pixels. In Seabroke, Holland & Cropper (2008), the first paper of this series, we motivated the need for such specialised 3D device modelling and outlined how its future resu...

  6. Equivalence of displacement radiation damage in superluminescent diodes induced by protons and heavy ions

    Science.gov (United States)

    Li, Xingji; Liu, Chaoming; Lan, Mujie; Xiao, Liyi; Liu, Jianchun; Ding, Dongfa; Yang, Dezhuang; He, Shiyu

    2013-07-01

    The degradation of optical power for superluminescent diodes is in situ measured under exposures of protons with various energies (170 keV, 3 MeV and 5 MeV), and 25 MeV carbon ions for several irradiation fluences. Experimental results show that the optical power of the SLDs decreases with increasing fluence. The protons with lower energies cause more degradation in the optical power of SLDs than those with higher energies at a given fluence. Compared to the proton irradiation with various energies, the 25 MeV carbon ions induce more severe degradation to the optical power. To characterize the radiation damage of the SLDs, the displacement doses as a function of chip depth in the SLDs are calculated by SRIM code for the protons and carbon ions. Based on the irradiation testing and calculation results, an approach is given to normalize the equivalence of displacement damage induced by various charged particles in SLDs.

  7. Analytical studies into radiation-induced starch damage in black and white peppers

    Science.gov (United States)

    Sharif, M. M.; Farkas, J.

    1993-07-01

    Temperature dependency of the apparent viscosity of heat-gelatinized suspensions of untreated and irradiated pepper samples has been investigated. There was a close linear correlation between the logaritm of "fluidity" /reciprocal of the apparent viscosity) and the reciprocal absolute temperature of the measurement. The slope of the regression line(the temperature dependence of fluidity) increased with the radiation dose. Gelatinization thermograms of aqueous suspensions of ground pepper samples were obtained by differential scanning calorimetry. Temperature characteristics of heat-gelatinization endotherms showed no significant differences between untreated and irradiated samples. A colorimetric method for damaged starch, the estimation of reducing power, and the alcohol-induced turbidity of aqueous extracts showed statistically significant increases of starch damage at doses higher than 4 kGy. These indices of starch-depolymerization have been changed less dramatically by irradiation than the apparent viscosity of the heat-gelatinized suspensions.

  8. OBJECT KINETIC MONTE CARLO SIMULATIONS OF RADIATION DAMAGE IN BULK TUNGSTEN

    Energy Technology Data Exchange (ETDEWEB)

    Nandipati, Giridhar; Setyawan, Wahyu; Heinisch, Howard L.; Roche, Kenneth J.; Kurtz, Richard J.; Wirth, Brian D.

    2015-09-22

    We used our recently developed lattice based OKMC code; KSOME [1] to carryout simulations of radiation damage in bulk W. We study the effect of dimensionality of self interstitial atom (SIA) diffusion i.e. 1D versus 3D on the defect accumulation during irradiation with a primary knock-on atom (PKA) energy of 100 keV at 300 K for the dose rates of 10-5 and 10-6 dpa/s. As expected 3D SIA diffusion significantly reduces damage accumulation due to increased probability of recombination events. In addition, dose rate, over the limited range examined here, appears to have no effect in both cases of SIA diffusion.

  9. DETECTION OF LOW DOSE RADIATION-AND CHEMICALLY-INDUCED DNA DAMAGE USING TEMPERATURE DIFFERENTIAL FLUORESCENCE ASSAYS

    Science.gov (United States)

    Rapid, sensitive and simple assays for radiation- and chemically-induced DNA damage can be of significant benefit to a number of fields including radiation biology, clinical research, and environmental monitoring. Although temperature-induced DNA strand separation has been use...

  10. Operational Experience and Performance with the ATLAS Pixel detector with emphasis on radiation damage

    CERN Document Server

    Butti, Pierfrancesco; The ATLAS collaboration

    2017-01-01

    The tracking performance of the ATLAS detector relies critically on its 4-layer Pixel Detector, that has undergone significant hardware and software upgrades to meet the challenges imposed by the higher collision energy, pileup and luminosity that are being delivered by the Large Hadron Collider, with record breaking instantaneous luminosities of 1.3 x 10^34 cm-2 s-1 recently surpassed. The key status and performance metrics of the ATLAS Pixel Detector are summarised, and the operational experience and requirements to ensure optimum data quality and data taking efficiency are described, with special emphasis to radiation damage experience.

  11. Operational Experience and Performance with the ATLAS Pixel detector with emphasis on radiation damage

    CERN Document Server

    Garcia Pascual, Juan Antonio; The ATLAS collaboration

    2017-01-01

    The tracking performance of the ATLAS detector relies critically on its 4-layer Pixel Detector, that has undergone significant hardware and software upgrades to meet the challenges imposed by the higher collision energy, pileup and luminosity that are being delivered by the Large Hadron Collider, with record breaking instantaneous luminosities of 1.3 x 10$^{34}$ cm$^{-2}$ s$^{-1}$ recently surpassed. The key status and performance metrics of the ATLAS Pixel Detector are summarised, and the operational experience and requirements to ensure optimum data quality and data taking efficiency are described, with special emphasis to radiation damage experience.

  12. Ultraviolet radiation, sun damage and preventing; Ultrafiolett straaling, solskader og forebygging

    Energy Technology Data Exchange (ETDEWEB)

    Johnsen, B.; Christensen, T.; Nilsen, L.T.; Hannevik, M.

    2013-03-01

    The report focuses on the large impact of health damages due to excessive UV exposure from natural sun. The first part of the report gives background information on factors significantly affecting the intensity of UV radiation. The second part gives an overview of health effects related to UV exposure, with recommendations on how to avoid excessive UV exposure and still enjoy the positive sides of outdoor activity. The report is intended to contribute to informational activities about sun exposure as recommended by the World Health Organisation and the World Meteorology Organisation. (Author)

  13. Surgical intervention for complications caused by late radiation damage of the small bowel; a retrospective analysis

    Energy Technology Data Exchange (ETDEWEB)

    Halteren, H.K. van; Gortzak, E.; Taal, B.G.; Helmerhorst, Th.J.M.; Aleman, B.M.P.; Hart, A.A.M.; Zoetmulder, F.A.N. (Nederlands Kanker Inst. ' Antoni van Leeuwenhoekhuis' , Amsterdam (Netherlands))

    1993-08-01

    The authors studied the records of 46 patients who had been operated on between 1974 and 1990 in the Netherlands Cancer Institute because of complications due to late radiation damage of the small bowel. The following factors led to an increase in complication-risk: hypalbuminemia. more than one laparotomy prior to irradiation and a short interval (< 12 months) between irradiation and surgical intervention. The following factors related to a poorer survival: incomplete resection of the primary tumor and a short interval (< 12 months) between irradiation and surgical intervention. The type f surgical intervention did not have cumulative prognostic value in relation to complication-risk or survival. (author).

  14. Annealing of natural metamict zircons. I low degree of radiation damage

    CERN Document Server

    Colombo, M

    1998-01-01

    In-situ time dependent high temperature X-ray powder diffraction was used to investigate the ordering process occurring during annealing of natural zircons with a low degree of radiation damage. It was possible to distinguish two stages of this process. Firstly, the diffusion of defects induced by alpha-particles, this stage contributes only to a certain degree of relaxation in the unit cell. In the second stage there is some degree of recrystallization. A hkl-dependence in the variation of the integrated intensity is observed and the increase in the volume of crystalline zircon is therefore related to a process of migration of dislocations.

  15. Annealing of natural metamict zircons: II high degree of radiation damage

    CERN Document Server

    Colombo, M

    1998-01-01

    In situ time-dependent high-temperature X-ray powder diffraction was used to study the amorphous to crystalline transition in natural zircons which are characterized by a high degree of radiation damage. It was possible to distinguish two stages of the annealing process: (i) the recovery of the heavily disturbed but still crystalline domains and (ii) the recrystallization of the amorphous regions. The first stage is very fast under the chosen experimental conditions and, at least apparently, is not thermally activated. The second stage is a diffusion-controlled process, whose products (zircon or zircon and zirconia phases) are strongly correlated to the annealing temperature.

  16. Sensitivity coefficients for the stochastic estimation of the radiation damage to the reactor pressure vessel

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, C.M.; Hernandez Valle, S. [Centro de Investigaciones Tecnologicas, Nucleares y Ambientales, La Habana (Cuba). E-mail: calvarez@ctn.isctn.edu.cu; svalle@ctn.isctn.edu.cu

    2000-07-01

    The construction of the sensitivity matrix in the case of the vessel radiation damage estimation by Monte Carlo techniques poses new problems related to the uncertainties of the obtained responses. In the case of deterministic calculations, the sensitivity coefficient obtention is a straightforward procedure based on the perturbation formalism through the calculation of the adjoint fluxes. In the paper an alternative procedure implementation based on the differential operator method is described with the modifications needed to the used HEXANN-EVALU code for the response estimations in the VVER-440 pressure vessel. (author)

  17. Measuring radiation damage dynamics by pulsed ion beam irradiation: 2016 project annual report

    Energy Technology Data Exchange (ETDEWEB)

    Kucheyev, Sergei O. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-01-04

    The major goal of this project is to develop and demonstrate a novel experimental approach to access the dynamic regime of radiation damage formation in nuclear materials. In particular, the project exploits a pulsed-ion-beam method in order to gain insight into defect interaction dynamics by measuring effective defect interaction time constants and defect diffusion lengths. For Year 3, this project had the following two major milestones: (i) the demonstration of the measurement of thermally activated defect-interaction processes by pulsed ion beam techniques and (ii) the demonstration of alternative characterization techniques to study defect dynamics. As we describe below, both of these milestones have been met.

  18. Threats to ICF reactor materials: computational simulations of radiation damage induced topological changes in fused silica

    CERN Document Server

    Kubota, A; Stolken, J; Sadigh, B; Reyes, S; Rubia, T D; Latkowski, J F

    2003-01-01

    We have performed molecular dynamics simulations of radiation damage in fused silica. In this study, we discuss the role of successive cascade overlap on the saturation and self-healing of oxygen vacancy defects in the amorphous fused silica network. Furthermore, we present findings on the topological changes in fused silica due to repeated energetic recoil atoms. These topological network modifications consistent with experimental Raman spectroscopic observation on neutron and ion irradiated fused silica are indicators of permanent densification that has also been observed experimentally.

  19. Resveratrol affects DNA damage induced by ionizing radiation in human lymphocytes in vitro.

    Science.gov (United States)

    Basso, Emiliano; Regazzo, Giulia; Fiore, Mario; Palma, Valentina; Traversi, Gianandrea; Testa, Antonella; Degrassi, Francesca; Cozzi, Renata

    2016-08-01

    Resveratrol (3,4',5-trihydroxystilbene; RSV) acts on cancer cells in several ways, inducing cell cycle delay and apoptotic death, and enhancing ionizing radiation (IR)-mediated responses. However, fewer studies have examined RSV effects on normal cells. We have treated human lymphocytes in vitro with RSV, either alone or combined with IR, to evaluate its potential use as a radioprotector. We measured the effects of RSV on induction of DNA damage, repair kinetics, and modulation of histone deacetylase activity. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. A Leakage Current-based Measurement of the Radiation Damage in the ATLAS Pixel Detector

    CERN Document Server

    Gorelov, Igor; 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 measurement 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.

  1. Using LEDs to stimulate the recovery of radiation damage to plastic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Wetzel, J., E-mail: james-wetzel@uiowa.edu [The University of Iowa, Iowa City, IA (United States); Tiras, E. [The University of Iowa, Iowa City, IA (United States); Bilki, B. [The University of Iowa, Iowa City, IA (United States); Beykent University, Istanbul (Turkey); Onel, Y. [The University of Iowa, Iowa City, IA (United States); Winn, D. [Fairfield University, Fairfield, CT (United States)

    2017-03-15

    In this study, we consider using LEDs to stimulate the recovery of scintillators damaged from radiation in high radiation environments. We irradiated scintillating tiles of polyethylene naphthalate (PEN), Eljen brand EJ-260 (EJN), an overdoped EJ-260 (EJ2P), and a lab-produced elastomer scintillator (ES) composed of p-terphenyl (ptp) in epoxy. Two different high-dose irradiations took place, with PEN dosed to 100 kGy, and the others to 78 kGy. We found that the ‘blue’ scintillators (PEN and ES) recovered faster and maximally higher with LEDs than without. Conversely exposing the ‘green’ scintillators (EJ-260) to LED light had a nearly negligible effect on the recovery. We hypothesize that the ‘green’ scintillators require wavelengths that match their absorption and emission spectra for LED stimulated recovery.

  2. Evaluation of radiation damage to Metal-Oxide-Semiconductor (MOS) devices

    Science.gov (United States)

    1982-12-01

    The purpose of these experiments was to provide qualitative and quantitative information on the effects of various hydrogen and nitrogen annealing treatments on the radiation hardness, or resistivity to damage, of MOS capacitors. Toward this end, the following tasks were performed: Construction of capacitor TO-5 packages for device evaluation; The experimental determination of the 1 MHz capacitance-voltage bias curves for both the pre- and post-irradiated capacitors; Evaluation of the change in Flat Band Voltage (Delta V sub fb) for the pre- and post-radiation stressed devices; Compilation of all 1 MHz data for cataloging purposes and the establishment of a benchmark for the new computer automated test system; and Reported data to the Contracting Officer's Technical Representative (COTR) on a case-by-case basis, as time was of the essence.

  3. Soft X-ray radiation-damage studies in PMMA using a cryo-STXM.

    Science.gov (United States)

    Beetz, Tobias; Jacobsen, Chris

    2003-05-01

    Radiation damage sets a fundamental limit for studies with ionizing radiation; cryo-methods are known to ease these limits. Here, measurements on mass loss and the decrease in the C=O bond density as measured by oxygen-edge XANES (NEXAFS) spectroscopy in thin films of poly(methylmethacrylate) (PMMA), studied in a vacuum, are reported. While cryo-methods allow more than 95% of the mass to remain at doses up to 10(7) Gy, there is little difference in C=O bond density versus dose between 298 K and 113 K sample temperatures. At both temperatures the critical dose for bond breaking is approximately 15 x 10(6) Gy.

  4. Space Radiation Effects on Human Cells: Modeling DNA Breakage, DNA Damage Foci Distribution, Chromosomal Aberrations and Tissue Effects

    Science.gov (United States)

    Ponomarev, A. L.; Huff, J. L.; Cucinotta, F. A.

    2011-01-01

    Future long-tem space travel will face challenges from radiation concerns as the space environment poses health risk to humans in space from radiations with high biological efficiency and adverse post-flight long-term effects. Solar particles events may dramatically affect the crew performance, while Galactic Cosmic Rays will induce a chronic exposure to high-linear-energy-transfer (LET) particles. These types of radiation, not present on the ground level, can increase the probability of a fatal cancer later in astronaut life. No feasible shielding is possible from radiation in space, especially for the heavy ion component, as suggested solutions will require a dramatic increase in the mass of the mission. Our research group focuses on fundamental research and strategic analysis leading to better shielding design and to better understanding of the biological mechanisms of radiation damage. We present our recent effort to model DNA damage and tissue damage using computational models based on the physics of heavy ion radiation, DNA structure and DNA damage and repair in human cells. Our particular area of expertise include the clustered DNA damage from high-LET radiation, the visualization of DSBs (DNA double strand breaks) via DNA damage foci, image analysis and the statistics of the foci for different experimental situations, chromosomal aberration formation through DSB misrepair, the kinetics of DSB repair leading to a model-derived spectrum of chromosomal aberrations, and, finally, the simulation of human tissue and the pattern of apoptotic cell damage. This compendium of theoretical and experimental data sheds light on the complex nature of radiation interacting with human DNA, cells and tissues, which can lead to mutagenesis and carcinogenesis later in human life after the space mission.

  5. Sunlight Responsive Thermochromic Window System

    Energy Technology Data Exchange (ETDEWEB)

    Millett, F,A; Byker,H, J

    2006-10-27

    Pleotint has embarked on a novel approach with our Sunlight Responsive Thermochromic, SRT™, windows. We are integrating dynamic sunlight control, high insulation values and low solar heat gain together in a high performance window. The Pleotint SRT window is dynamic because it reversibly changes light transmission based on thermochromics activated directly by the heating effect of sunlight. We can achieve a window package with low solar heat gain coefficient (SHGC), a low U value and high insulation. At the same time our windows provide good daylighting. Our innovative window design offers architects and building designers the opportunity to choose their desired energy performance, excellent sound reduction, external pane can be self-cleaning, or a resistance to wind load, blasts, bullets or hurricanes. SRT windows would provide energy savings that are estimated at up to 30% over traditional window systems. Glass fabricators will be able to use existing equipment to make the SRT window while adding value and flexibility to the basic design. Glazing installers will have the ability to fit the windows with traditional methods without wires, power supplies and controllers. SRT windows can be retrofit into existing buildings,

  6. Protective Effect of Pyruvate Against Radiation-Induced Damage in Collagenized Tissues

    Science.gov (United States)

    Griko, Y. V.; Yan, Xiaoli

    2016-01-01

    Exposure to high doses of ionizing radiation produces both acute and late effects on the collagenized tissues and have profound effects on wound healing. Because of the crucial practical importance for new radioprotective agents, our study has been focused on evaluation of the efficacy of non-toxic naturally occurring compounds to protect tissue integrity against high-dose gamma radiation. Here, we demonstrate that molecular integrity of collagen may serve as a sensitive biological marker for quantitative evaluation of molecular damage to collagenized tissue and efficacy of radioprotective agents. Increasing doses of gamma radiation (0-50kGy) result in progressive destruction of the native collagen fibrils, which provide a structural framework, strength, and proper milieu for the regenerating tissue. The strategy used in this study involved the thermodynamic specification of all structural changes in collagenized matrix of skin, aortic heart valve, and bone tissue induced by different doses and conditions of g-irradiation. This study describes a simple biophysical approach utilizing the Differential Scanning Calorimetry (DSC) to characterize the structural resistance of the aortic valve matrix exposed to different doses of g-irradiation. It allows us to identify the specific response of each constituent as well as to determine the influence of the different treatments on the characteristic parameters of protein structure. We found that pyruvate, a substance that naturally occurs in the body, provide significant protection (up to 80%) from biochemical and biomechanical damage to the collagenized tissue through the effective targeting of reactive oxygen species. The recently discovered role of pyruvate in the cell antioxidant defense to O2 oxidation, and its essential constituency in the daily human diet, indicate that the administration of pyruvate-based radioprotective formulations may provide safe and effective protection from deleterious effects of ionizing

  7. Pudendal Nerve and Internal Pudendal Artery Damage May Contribute to Radiation-Induced Erectile Dysfunction

    Energy Technology Data Exchange (ETDEWEB)

    Nolan, Michael W., E-mail: mwnolan@ncsu.edu [Department of Clinical Sciences, and Center for Comparative Medicine and Translational Research, North Carolina State University, Raleigh, North Carolina (United States); Department of Environmental and Radiologic Health Sciences, Colorado State University, Fort Collins, Colorado (United States); Marolf, Angela J. [Department of Environmental and Radiologic Health Sciences, Colorado State University, Fort Collins, Colorado (United States); Ehrhart, E.J. [Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado (United States); Rao, Sangeeta [Department of Clinical Sciences, Colorado State University, Fort Collins, Colorado (United States); Kraft, Susan L. [Department of Environmental and Radiologic Health Sciences, Colorado State University, Fort Collins, Colorado (United States); Engel, Stephanie [Department of Clinical Sciences, Colorado State University, Fort Collins, Colorado (United States); Yoshikawa, Hiroto; Golden, Anne E. [Department of Environmental and Radiologic Health Sciences, Colorado State University, Fort Collins, Colorado (United States); Wasserman, Todd H. [Department of Radiation Oncology, Washington University, St. Louis, Missouri (United States); LaRue, Susan M. [Department of Environmental and Radiologic Health Sciences, Colorado State University, Fort Collins, Colorado (United States)

    2015-03-15

    Purpose/Objectives: Erectile dysfunction is common after radiation therapy for prostate cancer; yet, the etiopathology of radiation-induced erectile dysfunction (RI-ED) remains poorly understood. A novel animal model was developed to study RI-ED, wherein stereotactic body radiation therapy (SBRT) was used to irradiate the prostate, neurovascular bundles (NVB), and penile bulb (PB) of dogs. The purpose was to describe vascular and neurogenic injuries after the irradiation of only the NVB or the PB, and after irradiation of all 3 sites (prostate, NVB, and PB) with varying doses of radiation. Methods and Materials: Dogs were treated with 50, 40, or 30 Gy to the prostate, NVB, and PB, or 50 Gy to either the NVB or the PB, by 5-fraction SBRT. Electrophysiologic studies of the pudendal nerve and bulbospongiosus muscles and ultrasound studies of pelvic perfusion were performed before and after SBRT. The results of these bioassays were correlated with histopathologic changes. Results: SBRT caused slowing of the systolic rise time, which corresponded to decreased arterial patency. Alterations in the response of the internal pudendal artery to vasoactive drugs were observed, wherein SBRT caused a paradoxical response to papaverine, slowing the systolic rise time after 40 and 50 Gy; these changes appeared to have some dose dependency. The neurofilament content of penile nerves was also decreased at high doses and was more profound when the PB was irradiated than when the NVB was irradiated. These findings are coincident with slowing of motor nerve conduction velocities in the pudendal nerve after SBRT. Conclusions: This is the first report in which prostatic irradiation was shown to cause morphologic arterial damage that was coincident with altered internal pudendal arterial tone, and in which decreased motor function in the pudendal nerve was attributed to axonal degeneration and loss. Further investigation of the role played by damage to these structures in RI-ED is

  8. Radiation damage to the normal monkey brain: experimental study induced by interstitial irradiation.

    Directory of Open Access Journals (Sweden)

    Mishima N

    2003-06-01

    Full Text Available Radiation damage to normal brain tissue induced by interstitial irradiation with iridium-192 seeds was sequentially evaluated by computed tomography (CT, magnetic resonance imaging (MRI, and histological examination. This study was carried out in 14 mature Japanese monkeys. The experimental area received more than 200-260 Gy of irradiation developed coagulative necrosis. Infiltration of macrophages to the periphery of the necrotic area was seen. In addition, neovascularization, hyalinization of vascular walls, and gliosis were found in the periphery of the area invaded by the macrophages. All sites at which the vascular walls were found to have acute stage fibrinoid necrosis eventually developed coagulative necrosis. The focus of necrosis was detected by MRI starting 1 week after the end of radiation treatment, and the size of the necrotic area did not change for 6 months. The peripheral areas showed clear ring enhancement with contrast material. Edema surrounding the lesions was the most significant 1 week after radiation and was reduced to a minimum level 1 month later. However, the edema then expanded once again and was sustained for as long as 6 months. CT did not provide as clear of a presentation as MRI, but it did reveal similar findings for the most part, and depicted calcification in the necrotic area. This experimental model is considered useful for conducting basic research on brachytherapy, as well as for achieving a better understanding of delayed radiation necrosis.

  9. Evaluation of γ-radiation-induced DNA damage in two species of bivalves and their relative sensitivity using comet assay.

    Science.gov (United States)

    Praveen Kumar, M K; Shyama, S K; Sonaye, B S; Naik, U Roshini; Kadam, S B; Bipin, P D; D'costa, A; Chaubey, R C

    2014-05-01

    Ionizing radiation is known to induce genetic damage in diverse groups of organisms. Under accidental situations, large quantities of radioactive elements get released into the environment and radiation emitted from these radionuclides may adversely affect both the man and the non-human biota. The present study is aimed (a) to know the genotoxic effect of gamma radiation on aquatic fauna employing two species of selected bivalves, (b) to evaluate the possible use of 'Comet assay' for detecting genetic damage in haemocytes of bivalves as a biomarker for environmental biomonitoring and also (c) to compare the relative sensitivity of two species of bivalves viz. Paphia malabarica and Meretrix casta to gamma radiation. The comet assays was optimized and validated using different concentrations (18, 32 and 56 mg/L) of ethyl methanesulfonate (EMS), a direct-acting reference genotoxic agent, to which the bivalves were exposed for various times (24, 48 and 72 h). Bivalves were irradiated (single acute exposure) with 5 different doses (viz. 2, 4, 6, 8 and 10 Gy) of gamma radiation and their genotoxic effects on the haemocytes were studied using the comet assay. Haemolymph was collected from the adductor muscle at 24, 48 and 72 h of both EMS-exposed and irradiated bivalves and comet assay was carried out using standard protocol. A significant increase in DNA damage was observed as indicated by an increase in % tail DNA damage at different concentrations of EMS and all the doses of gamma radiation as compared to controls in both bivalve species. This showed a dose-dependent increase of genetic damage induced in bivalves by EMS as well as gamma radiation. Further, the highest DNA damage was observed at 24h. The damage gradually decreased with time, i.e. was smaller at 48 and 72 h than at 24h post irradiation in both species of bivalves. This may indicate repair of the damaged DNA and/or loss of heavily damaged cells as the post irradiation time advanced. The present study

  10. Modelling single shot damage thresholds of multilayer optics for high-intensity short-wavelength radiation sources.

    Science.gov (United States)

    Loch, R A; Sobierajski, R; Louis, E; Bosgra, J; Bijkerk, F

    2012-12-17

    The single shot damage thresholds of multilayer optics for high-intensity short-wavelength radiation sources are theoretically investigated, using a model developed on the basis of experimental data obtained at the FLASH and LCLS free electron lasers. We compare the radiation hardness of commonly used multilayer optics and propose new material combinations selected for a high damage threshold. Our study demonstrates that the damage thresholds of multilayer optics can vary over a large range of incidence fluences and can be as high as several hundreds of mJ/cm(2). This strongly suggests that multilayer mirrors are serious candidates for damage resistant optics. Especially, multilayer optics based on Li(2)O spacers are very promising for use in current and future short-wavelength radiation sources.

  11. Combined small angle X-ray solution scattering with atomic force microscopy for characterizing radiation damage on biological macromolecules.

    Science.gov (United States)

    Costa, Luca; Andriatis, Alexander; Brennich, Martha; Teulon, Jean-Marie; Chen, Shu-Wen W; Pellequer, Jean-Luc; Round, Adam

    2016-10-27

    Synchrotron radiation facilities are pillars of modern structural biology. Small-Angle X-ray scattering performed at synchrotron sources is often used to characterize the shape of biological macromolecules. A major challenge with high-energy X-ray beam on such macromolecules is the perturbation of sample due to radiation damage. By employing atomic force microscopy, another common technique to determine the shape of biological macromolecules when deposited on flat substrates, we present a protocol to evaluate and characterize consequences of radiation damage. It requires the acquisition of images of irradiated samples at the single molecule level in a timely manner while using minimal amounts of protein. The protocol has been tested on two different molecular systems: a large globular tetremeric enzyme (β-Amylase) and a rod-shape plant virus (tobacco mosaic virus). Radiation damage on the globular enzyme leads to an apparent increase in molecular sizes whereas the effect on the long virus is a breakage into smaller pieces resulting in a decrease of the average long-axis radius. These results show that radiation damage can appear in different forms and strongly support the need to check the effect of radiation damage at synchrotron sources using the presented protocol.

  12. Graphene damage effects on radiation-resistance and configuration of copper–graphene nanocomposite under irradiation: A molecular dynamics study

    Science.gov (United States)

    Huang, Hai; Tang, Xiaobin; Chen, Feida; Liu, Jian; Li, Huan; Chen, Da

    2016-12-01

    Metal–graphene nanocomposite is a kind of potential radiation tolerant material. Graphene damage of the composite is inevitable within radiation environments. In this paper, two kinds of copper–graphene nanocomposite (CGNC) systems containing perfect graphene and prefabricated damage graphene, respectively, were adopted to expound the influences of graphene damage on the properties (radiation-resistance and configuration) of CGNC under irradiation by atomistic simulations. In the CGNC containing perfect graphene, the increasing graphene damage induced by the increase of the number of cascades, did not obviously impair the role of copper–graphene interface in keeping the properties of CGNC. In the CGNC containing prefabricated damage graphene, the properties of CGNC would significantly deteriorate once the radius of prefabricated damage exceeds 10 Å, and even stacking fault tetrahedral would occur in the CGNC. The results highlighted that prefabricated graphene damage have greater effects on the change of the properties of CGNC. Therefore, it is very necessary to maintain the structural integrity of graphene for improving the radiation-resistance and configuration of CGNC.

  13. Scintillation mechanism and radiation damage in Ce{sub x}La{sub 1-x}F{sub 3} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Wojtowicz, A.J.; Wisniewski, D. [Boston Univ., MA (United States)]|[N. Copernicus Univ., Torun (Poland); Lempicki, A.; Brecher, C. [Boston Univ., MA (United States); Bartram, R.H. [Univ. of Connecticut, Storrs (United States); Woody, C.; Levy, P.; Stoll, S.; Kierstead, J. [Brookhaven National Lab., Upton, NY (United States); Pedrini, C. [CNRS, Villeurbanne (France)] [and others

    1994-08-01

    Recent spectroscopic and radiation damage experiments on a series of Ce{sub x}La{sub 1{minus}x}F{sub 3} crystals suggest that the scintillation light output is limited by an unusual quenching mechanism, which also plays a major role in minimizing radiation-induced damage. The intensity of the radiation-induced absorptions is a strong function of the Ce content x, reaching a maximum for x = 0.03 and a minimum for x = 1. This peculiar dependence appears to be due to the influence of deep-lying Ce levels on both scintillation mechanism and radiation damage. The authors suggest that various charge transfer processes can explain many aspects of the performance of Ce{sub x}La{sub 1{minus}x}F{sub 3} scintillators.

  14. Radiation damage parameters for modelling of FRM irradiation conditions at the RADEX facility of INR RAS

    CERN Document Server

    Koptelov, E A; Sobolevsky, N M; Strebkov, Y S; Subbotin, A V

    2002-01-01

    Results of MC calculations of primary radiation damage generated by the intense proton beam at the RADiation EXperiment (RADEX) facility of the Institute for Nuclear Research, Russian Academy of Sciences (INR RAS) are presented. RADEX is the irradiation channel located inside a proton target at the beam stop of the INR RAS linear proton accelerator having energy up to 600 MeV. The position of the irradiation channel at the facility can be changed by rotation of the proton target relative to the vertical axis, thus varying the relative influence of the primary protons and spallation neutrons on the primary damage kinetics. By shifting the proton target position outside the horizontal beam axis, one may reduce the predominant input of high-energy protons to the irradiation field. As a result, the spectrum of primary knock-on atoms in the irradiated sample may be significantly softened. This gives the possibility of changing irradiation parameters to simulate irradiation conditions at other installations (ITER a...

  15. Ultraviolet Radiation, Aging and the Skin: Prevention of Damage by Topical cAMP Manipulation

    Directory of Open Access Journals (Sweden)

    Alexandra Amaro-Ortiz

    2014-05-01

    Full Text Available Being the largest and most visible organ of the body and heavily influenced by environmental factors, skin is ideal to study the long-term effects of aging. Throughout our lifetime, we accumulate damage generated by UV radiation. UV causes inflammation, immune changes, physical changes, impaired wound healing and DNA damage that promotes cellular senescence and carcinogenesis. Melanoma is the deadliest form of skin cancer and among the malignancies of highest increasing incidence over the last several decades. Melanoma incidence is directly related to age, with highest rates in individuals over the age of 55 years, making it a clear age-related disease. In this review, we will focus on UV-induced carcinogenesis and photo aging along with natural protective mechanisms that reduce amount of “realized” solar radiation dose and UV-induced injury. We will focus on the theoretical use of forskolin, a plant-derived pharmacologically active compound to protect the skin against UV injury and prevent aging symptoms by up-regulating melanin production. We will discuss its use as a topically-applied root-derived formulation of the Plectranthus barbatus (Coleus forskolii plant that grows naturally in Asia and that has long been used in various Aryuvedic teas and therapeutic preparations.

  16. The behaviour of copper in view of radiation damage in the LHC luminosity upgrade

    CERN Document Server

    Flukiger, R

    2013-01-01

    In view of the safe operation of the quadrupoles in the luminosity upgrade of the LHC accelerator, the response of the copper stabilizer at low temperatures to the various high energy radiation sources is of primary importance. The present study takes into account the expected high energy spectrum of the simultaneous radiation by neutrons, protons, pions, electrons and photons, calculated using the FLUKA code by F. Cerutti (CERN) as well as on literature values. It was found that proton irradiation causes a considerably higher damage than neutron irradiation: in spite of a 3.8% proton fraction, the measured damage is of the order of 20%, which fits with the calculations of N. Mokhov (Fermilab) on the contribution of protons to the dpa. The same calculations indicate that the total effect of protons, pions and electrons is at least as high as that of neutrons. Since recent neutron experiments of Nakamoto et al. show that the RRR of Cu is reduced from 200 to 50-120 for a fluence of 10^{21} n/cm^{2}, it follows ...

  17. Aqueous extract of Pinus caribaea inhibits the damage induced by ultraviolet radiations, in plasmid DNA

    Directory of Open Access Journals (Sweden)

    Marioly Vernhes Tamayo

    2017-08-01

    Full Text Available Context: The incidence of solar ultraviolet radiation (UV on Earth has increased due to diminish of the ozone layer. This enviromental agent is highly genotoxic causing numerous damage in DNA molecule. Nowadays there is a growing interest in the search of compounds capable to minimize these effects. In particular, phytocompounds have been tested as excelent candidates for their antigenotoxic properties. Aims: To evaluate the protective effect of the aqueous extract of Pinus caribaea (EPC against the damage induced by the UVB and UVC radiation. Methods: The cell-free plasmid DNA assay was employed. The forms of plasmid were separated electrophoretically in agarose gel. For genotoxic and photoprotective evaluation of P. caribaea, different concentrations of the extract (0.1 – 2.0 mg/mL and exposure times were evaluated. The CPD lesions were detected enzymatically. Additionally, the transmittance of the aqueous extract against 254 nm and 312 nm was measured. Results: None of the concentrations were genotoxic in 30 min of treatment, for superior times a clastogenic effect was observed. The EPC despite inhibiting the activity of the enzyme T4 endo V, impedes photolesions formation in DNA at concentrations ≥ 0.1 mg/mL. Conclusions: The EPC has photoprotective properties, this effect could be related with its antioxidants and absorptives capacities.

  18. Radiation damage to neutron and proton irradiated GaAs particle detectors

    CERN Document Server

    Rogalla, M; Evans, N; Joost, S; Kienzle-Focacci, M N; Geppert, R; Göppert, R; Irsigler, R; Ludwig, J; Runge, K; Schmid, T; Eich, Th.; Schmid, Th.

    1997-01-01

    The radiation damage in 200 um thick Schottky diodes made on semi-insulating (SI) undoped GaAs Liquid Encapsulated Czochralski (LEC) bulk material with resistivities between 0.4 and 8.9*10E7 Ohm*cm were studied using alpha-spectroscopy, signal response to minimum ionising particles (MIP), I-V and CV-measurements. The results have been analysed to investigate the influence of the substrate resistivity on the detector performance after neutron and proton irradiation. The leakage current density, signal response to alpha-particles and MIPs show a strong dependence on the resistivity before and after irradiation. An observed decrease of the electron mean free drift length before and after irradiation with increasing substrate resistivity can be explained by a model involving the different ionisation ratios of defects, which are introduced by the irradiation. Comparison of the radiation damage due to neutrons and protons gives a hardness factor of 7+-0.9 for 24 GeV/c protons. The best detectors show a response to ...

  19. Human salivary gland stem cells ameliorate hyposalivation of radiation-damaged rat salivary glands.

    Science.gov (United States)

    Jeong, Jaemin; Baek, Hyunjung; Kim, Yoon-Ju; Choi, Youngwook; Lee, Heekyung; Lee, Eunju; Kim, Eun Sook; Hah, Jeong Hun; Kwon, Tack-Kyun; Choi, Ik Joon; Kwon, Heechung

    2013-11-15

    Salivary function in mammals may be defective for various reasons, such as aging, Sjogren's syndrome or radiation therapy in head and neck cancer patients. Recently, tissue-specific stem cell therapy has attracted public attention as a next-generation therapeutic reagent. In the present study, we isolated tissue-specific stem cells from the human submandibular salivary gland (hSGSCs). To efficiently isolate and amplify hSGSCs in large amounts, we developed a culture system (lasting 4-5 weeks) without any selection. After five passages, we obtained adherent cells that expressed mesenchymal stem cell surface antigen markers, such as CD44, CD49f, CD90 and CD105, but not the hematopoietic stem cell markers, CD34 and CD45, and that were able to undergo adipogenic, osteogenic and chondrogenic differentiation. In addition, hSGSCs were differentiated into amylase-expressing cells by using a two-step differentiation method. Transplantation of hSGSCs to radiation-damaged rat salivary glands rescued hyposalivation and body weight loss, restored acinar and duct cell structure, and decreased the amount of apoptotic cells. These data suggest that the isolated hSGSCs, which may have characteristics of mesenchymal-like stem cells, could be used as a cell therapy agent for the damaged salivary gland.

  20. Ultraviolet radiation, aging and the skin: prevention of damage by topical cAMP manipulation.

    Science.gov (United States)

    Amaro-Ortiz, Alexandra; Yan, Betty; D'Orazio, John A

    2014-05-15

    Being the largest and most visible organ of the body and heavily influenced by environmental factors, skin is ideal to study the long-term effects of aging. Throughout our lifetime, we accumulate damage generated by UV radiation. UV causes inflammation, immune changes, physical changes, impaired wound healing and DNA damage that promotes cellular senescence and carcinogenesis. Melanoma is the deadliest form of skin cancer and among the malignancies of highest increasing incidence over the last several decades. Melanoma incidence is directly related to age, with highest rates in individuals over the age of 55 years, making it a clear age-related disease. In this review, we will focus on UV-induced carcinogenesis and photo aging along with natural protective mechanisms that reduce amount of "realized" solar radiation dose and UV-induced injury. We will focus on the theoretical use of forskolin, a plant-derived pharmacologically active compound to protect the skin against UV injury and prevent aging symptoms by up-regulating melanin production. We will discuss its use as a topically-applied root-derived formulation of the Plectranthus barbatus (Coleus forskolii) plant that grows naturally in Asia and that has long been used in various Aryuvedic teas and therapeutic preparations.

  1. Diffusion of fission products and radiation damage in SiC

    Science.gov (United States)

    Malherbe, Johan B.

    2013-11-01

    A major problem with most of the present nuclear reactors is their safety in terms of the release of radioactivity into the environment during accidents. In some of the future nuclear reactor designs, i.e. Generation IV reactors, the fuel is in the form of coated spherical particles, i.e. TRISO (acronym for triple coated isotropic) particles. The main function of these coating layers is to act as diffusion barriers for radioactive fission products, thereby keeping these fission products within the fuel particles, even under accident conditions. The most important coating layer is composed of polycrystalline 3C-SiC. This paper reviews the diffusion of the important fission products (silver, caesium, iodine and strontium) in SiC. Because radiation damage can induce and enhance diffusion, the paper also briefly reviews damage created by energetic neutrons and ions at elevated temperatures, i.e. the temperatures at which the modern reactors will operate, and the annealing of the damage. The interaction between SiC and some fission products (such as Pd and I) is also briefly discussed. As shown, one of the key advantages of SiC is its radiation hardness at elevated temperatures, i.e. SiC is not amorphized by neutrons or bombardment at substrate temperatures above 350 °C. Based on the diffusion coefficients of the fission products considered, the review shows that at the normal operating temperatures of these new reactors (i.e. less than 950 °C) the SiC coating layer is a good diffusion barrier for these fission products. However, at higher temperatures the design of the coated particles needs to be adapted, possibly by adding a thin layer of ZrC.

  2. Accelerated radiation damage test facility using a 5 MV tandem ion accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Wady, P.T., E-mail: paul.wady@manchester.ac.uk [Dalton Cumbrian Facility, University of Manchester, Westlakes Science & Technology Park, Moor Row, Cumbria CA24 3HA (United Kingdom); Draude, A.; Shubeita, S.M.; Smith, A.D.; Mason, N. [Dalton Cumbrian Facility, University of Manchester, Westlakes Science & Technology Park, Moor Row, Cumbria CA24 3HA (United Kingdom); Pimblott, S.M. [Dalton Cumbrian Facility, University of Manchester, Westlakes Science & Technology Park, Moor Row, Cumbria CA24 3HA (United Kingdom); School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Jimenez-Melero, E. [Dalton Cumbrian Facility, University of Manchester, Westlakes Science & Technology Park, Moor Row, Cumbria CA24 3HA (United Kingdom); School of Materials, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom)

    2016-01-11

    We have developed a new irradiation facility that allows to perform accelerated damage tests of nuclear reactor materials at temperatures up to 400 °C using the intense proton (<100 μA) and heavy ion (≈10 μA) beams produced by a 5 MV tandem ion accelerator. The dedicated beam line for radiation damage studies comprises: (1) beam diagnosis and focusing optical components, (2) a scanning and slit system that allows uniform irradiation of a sample area of 0.5–6 cm{sup 2}, and (3) a sample stage designed to be able to monitor in-situ the sample temperature, current deposited on the sample, and the gamma spectrum of potential radio-active nuclides produced during the sample irradiation. The beam line capabilities have been tested by irradiating a 20Cr–25Ni–Nb stabilised stainless steel with a 3 MeV proton beam to a dose level of 3 dpa. The irradiation temperature was 356 °C, with a maximum range in temperature values of ±6 °C within the first 24 h of continuous irradiation. The sample stage is connected to ground through an electrometer to measure accurately the charge deposited on the sample. The charge can be integrated in hardware during irradiation, and this methodology removes uncertainties due to fluctuations in beam current. The measured gamma spectrum allowed the identification of the main radioactive nuclides produced during the proton bombardment from the lifetimes and gamma emissions. This dedicated radiation damage beam line is hosted by the Dalton Cumbrian Facility of the University of Manchester.

  3. Ozone depletion and UVB radiation: impact on plant DNA damage in southern South America.

    Science.gov (United States)

    Rousseaux, M C; Ballaré, C L; Giordano, C V; Scopel, A L; Zima, A M; Szwarcberg-Bracchitta, M; Searles, P S; Caldwell, M M; Díaz, S B

    1999-12-21

    The primary motivation behind the considerable effort in studying stratospheric ozone depletion is the potential for biological consequences of increased solar UVB (280-315 nm) radiation. Yet, direct links between ozone depletion and biological impacts have been established only for organisms of Antarctic waters under the influence of the ozone "hole;" no direct evidence exists that ozone-related variations in UVB affect ecosystems of temperate latitudes. Indeed, calculations based on laboratory studies with plants suggest that the biological impact of ozone depletion (measured by the formation of cyclobutane pyrimidine dimers in DNA) is likely to be less marked than previously thought, because UVA quanta (315-400 nm) may also cause significant damage, and UVA is unaffected by ozone depletion. Herein, we show that the temperate ecosystems of southern South America have been subjected to increasingly high levels of ozone depletion during the last decade. We found that in the spring of 1997, despite frequent cloud cover, the passages of the ozone hole over Tierra del Fuego (55 degrees S) caused concomitant increases in solar UV and that the enhanced ground-level UV led to significant increases in DNA damage in the native plant Gunnera magellanica. The fluctuations in solar UV explained a large proportion of the variation in DNA damage (up to 68%), particularly when the solar UV was weighted for biological effectiveness according to action spectra that assume a sharp decline in quantum efficiency with increasing wavelength from the UVB into the UVA regions of the spectrum.

  4. Effect of adiponectin deficiency on intestinal damage and hematopoietic responses of mice exposed to gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ponemone, Venkatesh; Fayad, Raja; Gove, Melissa E.; Pini, Maria [Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, IL 60612 (United States); Fantuzzi, Giamila, E-mail: giamila@uic.edu [Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, IL 60612 (United States)

    2010-08-07

    Adiponectin (APN) is an adipose tissue-derived cytokine that regulates insulin sensitivity and inflammation. It is also involved in modulation of cell proliferation by binding to various growth factors. Based on its known effects in modulating cell proliferation and oxidative stress, APN may potentially be involved in regulating tissue damage and repair following irradiation. Adiponectin KO mice and their WT littermates were exposed to a single whole-body dose of 3 or 6 Gy gamma radiation. Radiation-induced alterations were studied in jejunum, blood, bone marrow and thymus at days 1 and 5 post-irradiation and compared with sham-irradiated groups. In WT mice, irradiation did not significantly alter serum APN levels while inducing a significant decrease in serum leptin. Irradiation caused a significant reduction in thymocyte cellularity, with concomitant decrease in CD4{sup +}, CD8{sup +} and CD4{sup +}CD8{sup +} T cell populations, with no significant differences between WT and APN KO mice. Irradiation resulted in a significantly higher increase in the frequency of micronucleated reticulocytes in the blood of APN KO compared with WT mice, whereas frequency of micronucleated normochromatic erythrocytes in the bone marrow at day 5 was significantly higher in WT compared with APN KO mice. Finally, irradiation induced similar alterations in villus height and crypt cell proliferation in the jejunum of WT and APN KO mice. Jejunum explants from sham-irradiated APN KO mice produced higher levels of IL-6 compared with tissue from WT animals, but the difference was no longer apparent following irradiation. Our data indicate that APN deficiency does not play a significant role in modulating radiation-induced gastrointestinal injury in mice, while it may participate in regulation of damage to the hematopoietic system.

  5. Proton radiation damage assessment of a CCD for use in a Ultraviolet and Visible Spectrometer

    Science.gov (United States)

    Gow, J. P. D.; Mason, J.; Leese, M.; Hathi, B.; Patel, M.

    2017-01-01

    This paper describes the radiation environment and radiation damage analysis performed for the Nadir and Occultation for MArs Discovery (NOMAD) Ultraviolet and Visible Spectrometer (UVIS) channel launched onboard the ExoMars Trace Gas Orbiter (TGO) in 2016. The aim of the instrument is to map the temporal and spatial variation of trace gases such as ozone and dust/cloud aerosols in the atmosphere of Mars. The instrument consists of a set of two miniature telescope viewing optics which allow for selective input onto the optical bench, where an e2v technologies CCD30-11 will be used as the detector. A Geometry Description Markup Language model of the spacecraft and instrument box was created and through the use of ESA's SPace ENVironment Information System (SPENVIS) an estimate of the 10 MeV equivalent proton fluence was made at a number of radiation sensitive regions within NOMAD, including that of the CCD30-11 which is the focus of this paper. The end of life 10 MeV equivalent proton fluence at the charge coupled device was estimated to be 4.7 × 109 protons.cm-2 three devices were irradiated at different levels up a 10 MeV equivalent fluence of 9.4 × 109 protons.cm-2. The dark current, charge transfer inefficiency, charge storage, and cosmetic quality of the devices was investigated pre- and post-irradiation, determining that the devices will continue to provide excellent science throughout the mission.

  6. Mechanism of Radiation Damage Reduction in Equiatomic Multicomponent Single Phase Alloys.

    Science.gov (United States)

    Granberg, F; Nordlund, K; Ullah, Mohammad W; Jin, K; Lu, C; Bei, H; Wang, L M; Djurabekova, F; Weber, W J; Zhang, Y

    2016-04-01

    Recently a new class of metal alloys, of single-phase multicomponent composition at roughly equal atomic concentrations ("equiatomic"), have been shown to exhibit promising mechanical, magnetic, and corrosion resistance properties, in particular, at high temperatures. These features make them potential candidates for components of next-generation nuclear reactors and other high-radiation environments that will involve high temperatures combined with corrosive environments and extreme radiation exposure. In spite of a wide range of recent studies of many important properties of these alloys, their radiation tolerance at high doses remains unexplored. In this work, a combination of experimental and modeling efforts reveals a substantial reduction of damage accumulation under prolonged irradiation in single-phase NiFe and NiCoCr alloys compared to elemental Ni. This effect is explained by reduced dislocation mobility, which leads to slower growth of large dislocation structures. Moreover, there is no observable phase separation, ordering, or amorphization, pointing to a high phase stability of this class of alloys.

  7. Late Ordovician geographic patterns of extinction compared with simulations of astrophysical ionizing radiation damage

    CERN Document Server

    Melott, Adrian L

    2008-01-01

    Based on the intensity and rates of various kinds of intense ionizing radiation events such as supernovae and gamma-ray bursts, it is likely that the Earth has been subjected to one or more events of potential mass extinction level intensity during the Phanerozoic. These induce changes in atmospheric chemistry so that the level of Solar ultraviolet-B radiation reaching surface and near-surface waters may be approximately doubled for up to one decade. This UVB level is known from experiment to be more than enough to kill off many kinds of organisms, particularly phytoplankton. It could easily induce a crash of the photosynthetic-based food chain in the oceans. Certain regularities in the latitudinal distribution of damage are apparent in computational simulations of the atmospheric changes. It was previously proposed that the late Ordovician extinction is a candidate for a contribution from an ionizing radiation event, based on environmental selectivity in trilobites. We confront this hypothesis with data from...

  8. Mechanism of Radiation Damage Reduction in Equiatomic Multicomponent Single Phase Alloys

    Science.gov (United States)

    Granberg, F.; Nordlund, K.; Ullah, Mohammad W.; Jin, K.; Lu, C.; Bei, H.; Wang, L. M.; Djurabekova, F.; Weber, W. J.; Zhang, Y.

    2016-04-01

    Recently a new class of metal alloys, of single-phase multicomponent composition at roughly equal atomic concentrations ("equiatomic"), have been shown to exhibit promising mechanical, magnetic, and corrosion resistance properties, in particular, at high temperatures. These features make them potential candidates for components of next-generation nuclear reactors and other high-radiation environments that will involve high temperatures combined with corrosive environments and extreme radiation exposure. In spite of a wide range of recent studies of many important properties of these alloys, their radiation tolerance at high doses remains unexplored. In this work, a combination of experimental and modeling efforts reveals a substantial reduction of damage accumulation under prolonged irradiation in single-phase NiFe and NiCoCr alloys compared to elemental Ni. This effect is explained by reduced dislocation mobility, which leads to slower growth of large dislocation structures. Moreover, there is no observable phase separation, ordering, or amorphization, pointing to a high phase stability of this class of alloys.

  9. Biophysical modelling of early and delayed radiation damage at chromosome level

    Science.gov (United States)

    Andreev, S.; Eidelman, Y.

    Exposure by ionising radiation increases cancer risk in human population Cancer is thought to originate from an altered expression of certain number of specific genes It is now widely recognised that chromosome aberrations CA are involved in stable change in expression of genes by gain or loss of their functions Thus CA can contribute to initiation or progression of cancer Therefore understanding mechanisms of CA formation in the course of cancer development might be valuable tool for quantification and prognosis of different stages of radiation carcinogenesis Early CA are defined as aberrations induced in first post-irradiation mitotic cycle The present work describes the original biophysical technique for early CA modelling It includes the following simulation steps the ionising particle track structure the structural organisation of all chromosomes in G 0 G 1 cell nucleus spatial distribution of radiation induced DNA double-strand breaks dsb within chromosomes dsb rejoining and misrejoining modelling cell cycle taking into account mitotic delay which results in complex time dependence of aberrant cells in first mitosis The results on prediction of dose-response curves for simple and complex CA measured in cells undergoing first division cycle are presented in comparison with recent experimental data There is increasing evidence that CA are also observed in descendents of irradiated cells many generations after direct DNA damage These delayed CA or chromosome instability CI are thought to be a manifestation of genome

  10. Accelerated aging tests of radiation damaged lasers and photodiodes for the CMS tracker optical links

    CERN Document Server

    Gill, K; Batten, J; Cervelli, G; Grabit, R; Jensen, F; Troska, Jan K; Vasey, F

    1999-01-01

    The combined effects of radiation damage and accelerated ageing in COTS lasers and p-i-n photodiodes are presented. Large numbers of these devices are employed in future High Energy Physics experiments and it is vital that these devices are confirmed to be sufficiently robust in terms of both radiation resistance and reliability. Forty 1310 nm InGaAsP edge-emitting lasers (20 irradiated) and 30 InGaAs p- i-n photodiodes (19 irradiated) were aged for 4000 hours at 80 degrees C with periodic measurements made of laser threshold and efficiency, in addition to p-i-n leakage current and photocurrent. There were no sudden failures and there was very little wearout- related degradation in either unirradiated or irradiated sample groups. The results suggest that the tested devices have a sufficiently long lifetime to operate for at least 10 years inside the Compact Muon Solenoid experiment despite being exposed to a harsh radiation environment. (13 refs).

  11. Molecular dynamics study of radiation damage and microstructure evolution of zigzag single-walled carbon nanotubes under carbon ion incidence

    Science.gov (United States)

    Li, Huan; Tang, Xiaobin; Chen, Feida; Huang, Hai; Liu, Jian; Chen, Da

    2016-07-01

    The radiation damage and microstructure evolution of different zigzag single-walled carbon nanotubes (SWCNTs) were investigated under incident carbon ion by molecular dynamics (MD) simulations. The radiation damage of SWCNTs under incident carbon ion with energy ranging from 25 eV to 1 keV at 300 K showed many differences at different incident sites, and the defect production increased to the maximum value with the increase in incident ion energy, and slightly decreased but stayed fairly stable within the majority of the energy range. The maximum damage of SWCNTs appeared when the incident ion energy reached 200 eV and the level of damage was directly proportional to incident ion fluence. The radiation damage was also studied at 100 K and 700 K and the defect production decreased distinctly with rising temperature because radiation-induced defects would anneal and recombine by saturating dangling bonds and reconstructing carbon network at the higher temperature. Furthermore, the stability of a large-diameter tube surpassed that of a thin one under the same radiation environments.

  12. Fundamental Processes of Coupled Radiation Damage and Mechanical Behavior in Nuclear Fuel Materials for High Temperature Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Phillpot, Simon; Tulenko, James

    2011-09-08

    The objective of this work has been to elucidate the relationship among microstructure, radiation damage and mechanical properties for nuclear fuel materials. As representative nuclear materials, we have taken an hcp metal (Mg as a generic metal, and Ti alloys for fast reactors) and UO2 (representing fuel). The degradation of the thermo-mechanical behavior of nuclear fuels under irradiation, both the fissionable material itself and its cladding, is a longstanding issue of critical importance to the nuclear industry. There are experimental indications that nanocrystalline metals and ceramics may be more resistant to radiation damage than their coarse-grained counterparts. The objective of this project look at the effect of microstructure on radiation damage and mechanical behavior in these materials. The approach to be taken was state-of-the-art, large-scale atomic-level simulation. This systematic simulation program of the effects of irradiation on the structure and mechanical properties of polycrystalline Ti and UO2 identified radiation damage mechanisms. Moreover, it will provided important insights into behavior that can be expected in nanocrystalline microstructures and, by extension, nanocomposites. The fundamental insights from this work can be expected to help in the design microstructures that are less susceptible to radiation damage and thermomechanical degradation.

  13. Degradação do pesticida Padron® por processos fotoquímicos utilizando luz artificial e solar Degradation of Padron® by photochemical processes using artificial and sunlight radiation

    Directory of Open Access Journals (Sweden)

    Silvio César Godinho Teixeira

    2007-01-01

    Full Text Available Destruction of Padron® (dye and picloram was evaluated using a photoreactor and a solar reactor. Photolysis was observed using only a germicide lamp (GL. Black light (BL and H2O2 (172 mmol L-1 promoted a conversion of 49% and 6% of dye and picloram, respectively. Photocatalytic processes were more efficient using TiO2/GL (96%-dye; 60%-picloram than TiO2/BL (44%-dye; 40%-picloram. Photolysis using sunlight was not observed during PadronÒ recirculation in the reactor constructed with four borosilicate tubes. Meanwhile, adding H2O2 resulted in 12% conversion of dissolved organic compounds. Finally, the most efficient mineralization (60% was obtained using the Fenton reaction ( H2O2-176 mmol L-1; FeSO4x6H2O-90 mmol L-1 and sunlight.

  14. Evaluation of γ-radiation-induced DNA damage in two species of bivalves and their relative sensitivity using comet assay

    Energy Technology Data Exchange (ETDEWEB)

    Praveen Kumar, M.K., E-mail: here.praveen@gmail.com [Department of Zoology, Goa University, Goa 403206 (India); Shyama, S.K., E-mail: skshyama@gmail.com [Department of Zoology, Goa University, Goa 403206 (India); Sonaye, B.S. [Department of Radiation Oncology, Goa Medical College, Goa (India); Naik, U Roshini; Kadam, S.B.; Bipin, P.D.; D’costa, A. [Department of Zoology, Goa University, Goa 403206 (India); Chaubey, R.C. [Radiation Biology and Health Science Division, Bhabha Atomic Research Centre, Mumbai (India)

    2014-05-01

    Highlights: • Possible genotoxic effect of accidental exposure of aquatic fauna to γ radiation. • Relative sensitivity of bivalves to γ radiation is also analyzed using comet assay. • γ radiation induced significant genetic damage in both the species of bivalves. • P. malabarica and M. casta exhibited a similar level of sensitivity to γ radiation. • Comet assay may be used as a biomarker for the environmental biomonitoring. - Abstract: Ionizing radiation is known to induce genetic damage in diverse groups of organisms. Under accidental situations, large quantities of radioactive elements get released into the environment and radiation emitted from these radionuclides may adversely affect both the man and the non-human biota. The present study is aimed (a) to know the genotoxic effect of gamma radiation on aquatic fauna employing two species of selected bivalves, (b) to evaluate the possible use of ‘Comet assay’ for detecting genetic damage in haemocytes of bivalves as a biomarker for environmental biomonitoring and also (c) to compare the relative sensitivity of two species of bivalves viz. Paphia malabarica and Meretrix casta to gamma radiation. The comet assays was optimized and validated using different concentrations (18, 32 and 56 mg/L) of ethyl methanesulfonate (EMS), a direct-acting reference genotoxic agent, to which the bivalves were exposed for various times (24, 48 and 72 h). Bivalves were irradiated (single acute exposure) with 5 different doses (viz. 2, 4, 6, 8 and 10 Gy) of gamma radiation and their genotoxic effects on the haemocytes were studied using the comet assay. Haemolymph was collected from the adductor muscle at 24, 48 and 72 h of both EMS-exposed and irradiated bivalves and comet assay was carried out using standard protocol. A significant increase in DNA damage was observed as indicated by an increase in % tail DNA damage at different concentrations of EMS and all the doses of gamma radiation as compared to controls in

  15. Characterization of radiation damage induced by swift heavy ions in graphite

    Energy Technology Data Exchange (ETDEWEB)

    Hubert, Christian

    2016-05-15

    Graphite is a classical material in neutron radiation environments, being widely used in nuclear reactors and power plants as a moderator. For high energy particle accelerators, graphite provides ideal material properties because of the low Z of carbon and its corresponding low stopping power, thus when ion projectiles interact with graphite is the energy deposition rather low. This work aims to improve the understanding of how the irradiation with swift heavy ions (SHI) of kinetic energies in the range of MeV to GeV affects the structure of graphite and other carbon-based materials. Special focus of this project is given to beam induced changes of thermo-mechanical properties. For this purpose the Highly oriented pyrolytic graphite (HOPG) and glassy carbon (GC) (both serving as model materials), isotropic high density polycrystalline graphite (PG) and other carbon based materials like carbon fiber carbon composites (CFC), chemically expanded graphite (FG) and molybdenum carbide enhanced graphite composites (MoC) were exposed to different ions ranging from {sup 131}Xe to {sup 238}U provided by the UNILAC accelerator at GSI in Darmstadt, Germany. To investigate structural changes, various in-situ and off-line measurements were performed including Raman spectroscopy, x-ray diffraction and x-ray photo-electron spectroscopy. Thermo-mechanical properties were investigated using the laser-flash-analysis method, differential scanning calorimetry, micro/nano-indentation and 4-point electrical resistivity measurements. Beam induced stresses were investigated using profilometry. Obtained results provided clear evidence that ion beam-induced radiation damage leads to structural changes and degradation of thermal, mechanical and electrical properties of graphite. PG transforms towards a disordered sp2 structure, comparable to GC at high fluences. Irradiation-induced embrittlement is strongly reducing the lifetime of most high-dose exposed accelerator components. For

  16. Source term and radiation dose estimates for postulated damage to the 102 Building at the General Electric Vallecitos Nuclear Center

    Energy Technology Data Exchange (ETDEWEB)

    Mishima, J.; McPherson, R.B.; Schwendiman, L.C.; Watson, E.C.; Ayer, J.E.

    1979-02-01

    Three scenarios representing significant levels of containment loss due to moderate, substantial, and major damage to the 102 Building at the Vallecitos Nuclear Center are postulated, and the potential radiation doses to the general population as a result of the airborne releases of radionuclides are estimated. The damage scenarios are not correlated to any specific level of seismic activity. The three scenarios are: (1) Moderate damage scenario--perforation of the enclosures in and the structure comprising the Plutonium Analytical Laboratory. (2) Substantial damage scenario--complete loss of containment of the Plutonium Analytical Laboratory and loss of the filters sealing the inlet to the Radioactive Materials Laboratory hot cells. (3) Major damage scenario--the damage outlined in (2) plus the perforation of enclosures holding significant inventories of dispersible plutonium in and the structure comprising the Advanced Fuels Laboratory.

  17. Detection of Low Level Microwave Radiation Induced Deoxyribonucleic Acid Damage Vis-à-vis Genotoxicity in Brain of Fischer Rats

    Science.gov (United States)

    Deshmukh, Pravin Suryakantrao; Megha, Kanu; Banerjee, Basu Dev; Ahmed, Rafat Sultana; Chandna, Sudhir; Abegaonkar, Mahesh Pandurang; Tripathi, Ashok Kumar

    2013-01-01

    Background: Non-ionizing radiofrequency radiation has been increasingly used in industry, commerce, medicine and especially in mobile phone technology and has become a matter of serious concern in present time. Objective: The present study was designed to investigate the possible deoxyribonucleic acid (DNA) damaging effects of low-level microwave radiation in brain of Fischer rats. Materials and Methods: Experiments were performed on male Fischer rats exposed to microwave radiation for 30 days at three different frequencies: 900, 1800 and 2450 MHz. Animals were divided into 4 groups: Group I (Sham exposed): Animals not exposed to microwave radiation but kept under same conditions as that of other groups, Group II: Animals exposed to microwave radiation at frequency 900 MHz at specific absorption rate (SAR) 5.953 × 10−4 W/kg, Group III: Animals exposed to 1800 MHz at SAR 5.835 × 10−4 W/kg and Group IV: Animals exposed to 2450 MHz at SAR 6.672 × 10−4 W/kg. At the end of the exposure period animals were sacrificed immediately and DNA damage in brain tissue was assessed using alkaline comet assay. Results: In the present study, we demonstrated DNA damaging effects of low level microwave radiation in brain. Conclusion: We concluded that low SAR microwave radiation exposure at these frequencies may induce DNA strand breaks in brain tissue. PMID:23833433

  18. Attempt at a medicolegal assessment of radiation damage as bodily injury. Der Versuch einer gerichtsmedizinischen Beurteilung des Strahlenschadens als Koerperverletzung

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, J.

    1970-02-20

    The dissertation shows on which basis an unsuccessful therapy or the inevitable consequence of therapy, radiation damage, can be prosecuted under penal law as bodily injury. A description is given of the nature and the different types of ionizing radiation, effects on the cell and on the human organism, types of damage, different degrees of sensitivity of the various organs, signs and symptoms in the human body, maximum doses, legal restrictions for different patient groups and organs. The problems involved in objectification and establishing a causal relationship between ionizing radiation and the manifest damage are pointed out clearly. The legal part of the work examines negligence, obligation to inform the patient, obligation to exercise due care, failure to do so and malpractice as possible criteria for culpable infliction of bodily injury. (HSCH).

  19. The Damage Mechanism and Protection of Electromagnetic Radiation%电磁辐射损伤机制与防护

    Institute of Scientific and Technical Information of China (English)

    郝娜; 程红缨; 任为; 缪春玉

    2012-01-01

    电磁辐射可导致动物心血管、神经、生殖、免疫等多系统不同程度损伤,严重威胁人类健康,电磁损伤的诊断和防治已成为亟待解决的问题.本文针对电磁辐射对靶器官的损伤作一综述,为电磁辐射的预防、诊断、防治和护理提供依据.%Studies have shown that electromagnetic radiation can cause varying degrees of damage to the cardiovascular, nervous, reproductive and immune systems. Diagnosis and control of electromagnetic damage has become a serious problem and a threat to human health. In this paper, electromagnetic radiation damage to target organs is reviewed. Evidence is provided for, electromagnetic radiation prevention, diagnosis and the basis for medical treatment.

  20. Observation of radiation-specific damage in cells exposed to depleted uranium: hprt gene mutation frequency

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Alexandra C. [Science Research Departments, Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, 8901 Wisconsin Avenue, Bethesda, MD 20889-5603 (United States)], E-mail: millera@afrri.usuhs.mil; Stewart, Michael; Rivas, Rafael [Science Research Departments, Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, 8901 Wisconsin Avenue, Bethesda, MD 20889-5603 (United States); Marino, Steve; Randers-Pehrson, Gerhard [Center for Radiological Research, Columbia University, 630 W. 168th St. VC11-215, New York, NY 10032 (United States); Shi Lin [Science Research Departments, Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, 8901 Wisconsin Avenue, Bethesda, MD 20889-5603 (United States)

    2007-07-15

    Depleted uranium (DU) is a dense heavy metal used primarily in military applications. Published data from our laboratory have demonstrated that DU exposure in vitro to immortalized human osteoblast cells (HOS) is both neoplastically transforming and genotoxic. Recent animal studies have also shown that DU is leukemogenic and genotoxic. DU possesses both a radiological (alpha particle) and chemical (metal) component. Since DU has a low specific activity in comparison to natural uranium, it is not considered to be a significant radiological hazard. The potential contribution of radiation to DU-induced biological effects is unknown, and the involvement of radiation in DU-induced biological effects could have significant implications for current risk estimates for internalized DU exposure. The purpose of the current study was to measure the induction of mutagenic damage in V79 cells and to determine if radiation plays a role in the induction of that damage. Mutagenicity at the hypoxanthine (guanine) phosphoribosyltransferase (hprt) locus was measured by selection with 6-thioguanine. There was a dose-dependent increase in mutagenic response following DU exposure (10-50{mu}m); the average increase in mutagenicity above background ranged from 2.54{+-}1.19 to 8.75{+-}1.8(P<0.05). Using the same concentration (25{mu}M) of two uranyl nitrate compounds that have different uranium isotopic concentrations and, therefore, different specific activities, we examined the effect on hprt mutant frequency in vitro. V79 cells were exposed to either {sup 238}U-uranyl nitrate, specific activity 0.33{mu}Ci/g, or DU-uranyl nitrate, specific activity 0.44{mu}Ci/g, delivered at a concentration of 25{mu}M for 24 h. Results showed, that at equal uranium concentration, a 1.33-fold increase in specific activity resulted in a 1.27{+-}0.11-fold (P<0.05) increase in hprt mutant frequency. Taken together these data support earlier results showing that radiation can play a role in DU

  1. Sunlight exposure: Do health benefits outweigh harm?

    Science.gov (United States)

    Razzaque, Mohammed S

    2016-09-16

    Vitamin D is a fat-soluble vitamin whose levels within the body are elevated following sunlight exposure. Numerous studies have shown that sunlight exposure can provide protection to a wide variety of diseases, ranging from different types of tumors to hypertension to type 1 diabetes to multiple sclerosis. Moreover, studies have shown that avoiding sunlight may influence the initiation and progression of some of these diseases. Avoidance of sunlight, coupled with the inclination towards consuming supplements, is becoming the primary choice to obtain vitamin D. The purpose of this article is to present evidences from published literature, to show that the expected benefits of vitamin D supplements are minimized by the potential risk of cardiovascular events and beyond. Since hypovitaminosis D status usually reflects reduced sunlight exposure, the obvious primary replacement should be safe sunlight exposure, and not exogenous supplements. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Radiation Damage in Nuclear Fuel for Advanced Burner Reactors: Modeling and Experimental Validation

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Niels Gronbech; Asta, Mark; Ozolins, Nigel Browning' Vidvuds; de Walle, Axel van; Wolverton, Christopher

    2011-12-29

    The consortium has completed its existence and we are here highlighting work and accomplishments. As outlined in the proposal, the objective of the work was to advance the theoretical understanding of advanced nuclear fuel materials (oxides) toward a comprehensive modeling strategy that incorporates the different relevant scales involved in radiation damage in oxide fuels. Approaching this we set out to investigate and develop a set of directions: 1) Fission fragment and ion trajectory studies through advanced molecular dynamics methods that allow for statistical multi-scale simulations. This work also includes an investigation of appropriate interatomic force fields useful for the energetic multi-scale phenomena of high energy collisions; 2) Studies of defect and gas bubble formation through electronic structure and Monte Carlo simulations; and 3) an experimental component for the characterization of materials such that comparisons can be obtained between theory and experiment.

  3. Technical Scope of Work: Proton Induced Radiation Damage in Crystal Scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Ren-Yuan [California Inst. of Technology (CalTech), Pasadena, CA (United States); Zhang, Liyuan [California Inst. of Technology (CalTech), Pasadena, CA (United States); Yang, Fan [California Inst. of Technology (CalTech), Pasadena, CA (United States); Ramberg, Eric [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Nebel, Todd [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2014-03-11

    This is a technical scope of work (TSW) between the Fermi National Accelerator Laboratory (Fermilab) and the experimenters of California Institute of Technology who have committed to participate in beam tests to be carried out during the 2014 Fermilab Test Beam Facility program. The goal of this investigation is to understand the proton-induced radiation damage in candidate fast crystal scintillators for future HEP experiments. Degradations of the optical and scintillation properties, including emission and transmittance spectra, light output, decay time and light response uniformity, will be measured before and after each step of proton irradiation at Fermilab with a defined fluence. The irradiation will start with a fluence of 1010/cm2 and going up in four steps to 1013/cm2.

  4. Radiation damage and tritium release from Li-Zr-Si oxides

    Energy Technology Data Exchange (ETDEWEB)

    Pfeiffer, H.; Bosch, P. [Universidad Autonoma Metropolitana-Iztapalapa, Dept. de Quimica (Mexico); Lopez, B.; Jimenez-Becerril, J.; Bulbulian, S. [Instituto Nacional de Investigaciones Nucleares, Dept. de Quimica (Mexico)

    2002-04-01

    Li-Zr-Si mixed oxides were irradiated in a mixed radiation field in order to produce tritium through the Li{sup 6}(n, {alpha})H{sup 3} reaction. The LiZrSiO{sub 4} samples, prepared with different Li:Zr molar ratios (1, 3, 5 and 6), presented high tritium diffusion compared with other lithium ceramics like Li{sub 2}SiO{sub 3} and Li{sub 2}ZrO{sub 3}. Furthermore, their composition and structure were not modified after irradiation. It was also found that Li{sub 2}ZrSi{sub 6}O{sub 15} was damaged by irradiation, and that tritium release was moderate in this compound. (authors)

  5. The effect of C concentration on radiation damage in Fe–Cr–C alloys

    Energy Technology Data Exchange (ETDEWEB)

    Meinander, A., E-mail: andrea.meinander@helsinki.fi [EURATOM-Tekes, Department of Physics, P.O. Box 43, FI-00014 University of Helsinki (Finland); Henriksson, K.O.E. [EURATOM-Tekes, Department of Physics, P.O. Box 43, FI-00014 University of Helsinki (Finland); Björkas, C. [EURATOM-Tekes, Department of Physics, P.O. Box 43, FI-00014 University of Helsinki (Finland); Institute of Energy and Climate Research – Plasma Physics, Forschungszentrum Jülich GmbH, Association EURATOM-FZJ, Partner in the Trilateral Euregio Cluster, Jülich (Germany); Vörtler, K.; Nordlund, K. [EURATOM-Tekes, Department of Physics, P.O. Box 43, FI-00014 University of Helsinki (Finland)

    2013-11-15

    Using a recently developed analytical bond-order potential for the complete ternary system, we performed molecular dynamics simulations of the primary radiation damage by displacement cascades in different Fe–Cr–C model alloys. We compared results obtained with this new potential to previous studies employing potentials for the binary Fe–Cr and Fe–C systems. We analysed the effect of C concentration on the number of Frenkel pairs produced by the cascades, as well as on clustering of vacancies and self-interstitial atoms (SIAs), and on the Cr and C content in the defects. The effect of C concentration on defect production was negligible, except at very high concentrations of over 1 at.% C. The main effect was in the Cr content of clustered SIAs, which increased with increasing C concentration.

  6. Radiation Damage and Recovery in Neutron-Irradiated MgO Crystal

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    MgO single crystal was irradiated by neutron up to a dose of 5.74×1018 cm-2. The radiation damage and its recovery were studied by means of UV-VIS and EM spectroscopy. The results indicate that the irradiation generates large amount of optically detectable defects such as single anion vacancies (F+ center), anion divacancies (F2) and some higher order defects. Through isochronal annealing, these defects started a series of processes of diminishing and transforming, and finally all disappeared while annealing at 900 ℃. It seems that the absorption bands of 573 nm are resulted from a higher order and more complex aggregated center than that of 424, 451 nm bands.

  7. Technical Scope of Work: Proton Induced Radiation Damage in Crystal Scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Ren-Yuan [California Inst. of Technology (CalTech), Pasadena, CA (United States); Zhang, Liyuan [California Inst. of Technology (CalTech), Pasadena, CA (United States); Yang, Fan [California Inst. of Technology (CalTech), Pasadena, CA (United States); Ramberg, Eric [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Nebel, Todd [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2014-03-11

    This is a technical scope of work (TSW) between the Fermi National Accelerator Laboratory (Fermilab) and the experimenters of California Institute of Technology who have committed to participate in beam tests to be carried out during the 2014 Fermilab Test Beam Facility program. The goal of this investigation is to understand the proton induced radiation damage in candidate fast crystal scintillators for future HEP experiments. Degradations of the optical and scintillation properties, including emission and transmittance spectra, light output, decay time and light response uniformity, will be measured before and after each step of proton irradiation at Fermilab with a defined fluence. The irradiation will start with a fluence of 1010/cm2 and going up in four steps to 1013/cm2.

  8. Radiation damage study on diamond sensors of the ALICE Beam Condition Monitoring system

    CERN Document Server

    Vai, Ilaria

    2013-01-01

    The ALICE Beam Monitoring System has been developed with the aim of detecting beam failures that can affect the experimental region. It is composed of synthetic diamonds as detector, a material that is particularly adapt to harsh radiation environment. However some sensors have shown an increase in the noise in the last year of operation. For this reason, I have developed a station to study the working parameters of the diamond sensors used in this system, in order to check their conditions. I've found an increase of the dark current of almost all the sensors and, in particular, the sensors of the system BCM-A seem to have suffered a greater damage than the others.

  9. Revealing low-dose radiation damage using single-crystal spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Owen, Robin L., E-mail: robin.owen@diamond.ac.uk [Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, OX11 0DE (United Kingdom); Yorke, Briony A.; Gowdy, James A.; Pearson, Arwen R. [University of Leeds, Leeds (United Kingdom)

    2011-05-01

    Data on the rapid reduction of haem proteins in the X-ray beam at synchrotron sources are presented. The use of single-crystal spectroscopy to detect these changes and their implication for diffraction data collection from oxidized species is also discussed. The structural information and functional insight obtained from X-ray crystallography can be enhanced by the use of complementary spectroscopies. Here the information that can be obtained from spectroscopic methods commonly used in conjunction with X-ray crystallography and best-practice single-crystal UV-Vis absorption data collection are briefly reviewed. Using data collected with the in situ system at the Swiss Light Source, the time and dose scales of low-dose X-ray-induced radiation damage and solvated electron generation in metalloproteins at 100 K are investigated. The effect of dose rate on these scales is also discussed.

  10. On radiation damage in FIB-prepared softwood samples measured by scanning X-ray diffraction.

    Science.gov (United States)

    Storm, Selina; Ogurreck, Malte; Laipple, Daniel; Krywka, Christina; Burghammer, Manfred; Di Cola, Emanuela; Müller, Martin

    2015-03-01

    The high flux density encountered in scanning X-ray nanodiffraction experiments can lead to severe radiation damage to biological samples. However, this technique is a suitable tool for investigating samples to high spatial resolution. The layered cell wall structure of softwood tracheids is an interesting system which has been extensively studied using this method. The tracheid cell has a complex geometry, which requires the sample to be prepared by cutting it perpendicularly to the cell wall axis. Focused ion beam (FIB) milling in combination with scanning electron microscopy allows precise alignment and cutting without splintering. Here, results of a scanning X-ray diffraction experiment performed on a biological sample prepared with a focused ion beam of gallium atoms are reported for the first time. It is shown that samples prepared and measured in this way suffer from the incorporation of gallium atoms up to a surprisingly large depth of 1 µm.

  11. Influence of trans fat on skin damage in first-generation rats exposed to UV radiation.

    Science.gov (United States)

    Barcelos, Raquel Cristine S; Vey, Luciana T; Segat, Hecson Jesser; Benvegnú, Dalila M; Trevizol, Fabíola; Roversi, Karine; Roversi, Katiane; Dias, Verônica T; Dolci, Geisa S; Kuhn, Fábio T; Piccolo, Jaqueline; CristinaVeit, Juliana; Emanuelli, Tatiana; Bürger, Marilise E

    2015-01-01

    The influence of trans fatty acids (TFA) on lipid profile, oxidative damage and mitochondrial function in the skin of rats exposed to ultraviolet radiation (UVR) was assessed. The first-generation offspring of female Wistar rats supplemented from pregnancy with either soybean oil (C-SO, rich in n-6 FA; control group) or hydrogenated vegetable fat (HVF, rich in TFA) were continued with the same supplements until adulthood, when half of each group was exposed to UVR for 12 weeks. The HVF group showed higher TFA cutaneous incorporation, increased protein carbonyl (PC) levels, decreased functionality of mitochondrial enzymes and antioxidant defenses of the skin. After UVR, the HVF group showed increased skin thickness and reactive species (RS) generation, with decreased skin antioxidant defenses. RS generation was positively correlated with skin thickness, wrinkles and PC levels. Once incorporated to skin, TFA make it more susceptible to developing UVR-induced disorders.

  12. Influence of XRCC1 Genetic Polymorphisms on Ionizing Radiation-Induced DNA Damage and Repair

    Science.gov (United States)

    Sterpone, Silvia; Cozzi, Renata

    2010-01-01

    It is well known that ionizing radiation (IR) can damage DNA through a direct action, producing single- and double-strand breaks on DNA double helix, as well as an indirect effect by generating oxygen reactive species in the cells. Mammals have evolved several and distinct DNA repair pathways in order to maintain genomic stability and avoid tumour cell transformation. This review reports important data showing a huge interindividual variability on sensitivity to IR and in susceptibility to developing cancer; this variability is principally represented by genetic polymorphisms, that is, DNA repair gene polymorphisms. In particular we have focussed on single nucleotide polymorphisms (SNPs) of XRCC1, a gene that encodes for a scaffold protein involved basically in Base Excision Repair (BER). In this paper we have reported and presented recent studies that show an influence of XRCC1 variants on DNA repair capacity and susceptibility to breast cancer. PMID:20798883

  13. A radiation damage test for double-sided silicon strip detectors

    CERN Document Server

    Iwata, Y; Ikeda, M; Kitabayashi, H; Ohmoto, T; Kondo, T; Unno, Y; Terada, S; Kohriki, T; Takashima, R

    2002-01-01

    In order to investigate the p-side strip isolation, position sensitivity and charge collection of type-inverted double-sided silicon microstrip detectors, signal amplitude and charge sharing of adjacent strips were measured by using a laser test stand, following the irradiation with a flux of 3.8x10 sup 1 sup 3 /cm sup 2 of 12 GeV protons. The irradiated detectors indicated high bulk resistivity, which results in maintaining a position sensitivity of the ohmic contact side even below the full depletion voltage. This fact suggests a possibility of operation of a double-sided detector whose full depletion voltage becomes higher than its breakdown limit because of a radiation damage.

  14. Influence of XRCC1 Genetic Polymorphisms on Ionizing Radiation-Induced DNA Damage and Repair

    Directory of Open Access Journals (Sweden)

    Silvia Sterpone

    2010-01-01

    Full Text Available It is well known that ionizing radiation (IR can damage DNA through a direct action, producing single- and double-strand breaks on DNA double helix, as well as an indirect effect by generating oxygen reactive species in the cells. Mammals have evolved several and distinct DNA repair pathways in order to maintain genomic stability and avoid tumour cell transformation. This review reports important data showing a huge interindividual variability on sensitivity to IR and in susceptibility to developing cancer; this variability is principally represented by genetic polymorphisms, that is, DNA repair gene polymorphisms. In particular we have focussed on single nucleotide polymorphisms (SNPs of XRCC1, a gene that encodes for a scaffold protein involved basically in Base Excision Repair (BER. In this paper we have reported and presented recent studies that show an influence of XRCC1 variants on DNA repair capacity and susceptibility to breast cancer.

  15. Simulation of thermal ageing and radiation damage in Fe-Cr

    Energy Technology Data Exchange (ETDEWEB)

    Wallenius, Janne [Department of Reactor Physics, KTH, AlbaNova University Centre, 106 91 Stockholm (Sweden)]. E-mail: janne@neutron.kth.se; Olsson, Paer [Department Materiaux et Mecanique des Composants, Electricite de France, EDF-R and D, Les Renardieres, F-77250 Moret sur Loing (France); Malerba, Lorenzo [SCK-CEN, Belgian Nuclear Research Centre, Boeretang 200, B-2400 Mol (Belgium); Terentyev, Dmitry [SCK-CEN, Belgian Nuclear Research Centre, Boeretang 200, B-2400 Mol (Belgium)

    2007-02-15

    In recent years substantial progress has been made in the field of multi-scale modelling of radiation damage Fe-Cr alloy. Ab initio calculations have provided a description of point-defect properties for a large number of defect configurations. Empirical potentials for the alloy of EAM and 2nd moment tight binding type have been constructed that reproduce these formation energies, as well as the anomalous shift in sign of mixing enthalpy at a Cr concentration of about 10%. Applying the potentials in simulation of interstitial cluster transport, it has been found that cluster diffusion coefficients have shallow minima corresponding to experimentally measured minima in swelling rates of Fe-Cr alloys. Kinetic Monte Carlo simulation of thermal ageing further show that these potentials correctly reproduce the formation modes of the alpha-prime phase for Cr concentrations above 9%. The present paper is a review of methods used and results achieved within the last couple of years.

  16. Radiation Damage in Nuclear Fuel for Advanced Burner Reactors: Modeling and Experimental Validation

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Niels Gronbech; Asta, Mark; Ozolins, Nigel Browning' Vidvuds; de Walle, Axel van; Wolverton, Christopher

    2011-12-29

    The consortium has completed its existence and we are here highlighting work and accomplishments. As outlined in the proposal, the objective of the work was to advance the theoretical understanding of advanced nuclear fuel materials (oxides) toward a comprehensive modeling strategy that incorporates the different relevant scales involved in radiation damage in oxide fuels. Approaching this we set out to investigate and develop a set of directions: 1) Fission fragment and ion trajectory studies through advanced molecular dynamics methods that allow for statistical multi-scale simulations. This work also includes an investigation of appropriate interatomic force fields useful for the energetic multi-scale phenomena of high energy collisions; 2) Studies of defect and gas bubble formation through electronic structure and Monte Carlo simulations; and 3) an experimental component for the characterization of materials such that comparisons can be obtained between theory and experiment.

  17. Patterns in ultraviolet radiation sensitivity of tropical, temperate and Arctic marine macroalgae

    NARCIS (Netherlands)

    van de Poll, Willem Hendrik

    2003-01-01

    Marine macroalgae on rocky substrates are an important component of the coastal ecosystem in terms of biomass and diversity. Because macroalgae depend on sunlight to drive photosynthesis they also face exposure to harmful ultraviolet-B radiation (UVBR: 280-315 nm). UVBR induces DNA damage (mainly cy

  18. Patterns in ultraviolet radiation sensitivity of tropical, temperate and Arctic marine macroalgae

    NARCIS (Netherlands)

    van de Poll, Willem Hendrik

    2003-01-01

    Marine macroalgae on rocky substrates are an important component of the coastal ecosystem in terms of biomass and diversity. Because macroalgae depend on sunlight to drive photosynthesis they also face exposure to harmful ultraviolet-B radiation (UVBR: 280-315 nm). UVBR induces DNA damage (mainly cy

  19. HST/WFC3: understanding and mitigating radiation damage effects in the CCD detectors

    Science.gov (United States)

    Baggett, S. M.; Anderson, J.; Sosey, M.; Gosmeyer, C.; Bourque, M.; Bajaj, V.; Khandrika, H.; Martlin, C.

    2016-07-01

    At the heart of the Hubble Space Telescope Wide Field Camera 3 (HST/WFC3) UVIS channel is a 4096x4096 pixel e2v CCD array. While these detectors continue to perform extremely well after more than 7 years in low-earth orbit, the cumulative effects of radiation damage are becoming increasingly evident. The result is a continual increase of the hotpixel population and the progressive loss in charge-transfer efficiency (CTE) over time. The decline in CTE has two effects: (1) it reduces the detected source flux as the defects trap charge during readout and (2) it systematically shifts source centroids as the trapped charge is later released. The flux losses can be significant, particularly for faint sources in low background images. In this report, we summarize the radiation damage effects seen in WFC3/UVIS and the evolution of the CTE losses as a function of time, source brightness, and image-background level. In addition, we discuss the available mitigation options, including target placement within the field of view, empirical stellar photometric corrections, post-flash mode and an empirical pixel-based CTE correction. The application of a post-flash has been remarkably effective in WFC3 at reducing CTE losses in low-background images for a relatively small noise penalty. Currently, all WFC3 observers are encouraged to consider post-flash for images with low backgrounds. Finally, a pixel-based CTE correction is available for use after the images have been acquired. Similar to the software in use in the HST Advanced Camera for Surveys (ACS) pipeline, the algorithm employs an observationally-defined model of how much charge is captured and released in order to reconstruct the image. As of Feb 2016, the pixel-based CTE correction is part of the automated WFC3 calibration pipeline. Observers with pre-existing data may request their images from MAST (Mikulski Archive for Space Telescopes) to obtain the improved products.

  20. Atomistic investigation of Cr influence on primary radiation damage in Fe-12 at.% Cr grain boundaries

    Science.gov (United States)

    Esfandiarpour, A.; Feghhi, S. A. H.; Arjhangmehr, A.

    2016-08-01

    In this paper, we investigate the influence of Cr on the primary radiation damage in Fe-12 at.% Cr with different atomic grain boundaries (GBs). Four different GB structures, two twists and two symmetric tilt boundaries are selected as the model structures. The primary radiation damage near each GB in α-Fe and Fe-12 at.% Cr is simulated using Molecular Dynamics for 9 keV primary knock-on atoms with velocity vectors perpendicular to the GB plane. In agreement with previous works, the results indicate that the atomic GBs are biased toward interstitials and due to the reduction of ‘in-cascade’ interstitial-vacancy annihilation rates, vacancies accumulate in the bulk grains. The minimum defect production occurs when the overlap between cascade center and GB plane is maximum; in contrast, the number of residual defects in the bulk (vacancies and interstitials) increases when the overlap decreases. Moreover, we find that the presence of Cr hardly affects the number of residual defects in the grain interiors, and causes a Cr-enrichment in the surviving self-interstitial atoms in bulk during relaxation of the primary cascades—also in agreement with previous studies. Further, in order to study the effect of 12 at.% Cr on the energetic and kinetic properties of vacancies near the atomic GBs, we calculate formation energies and diffusion barriers of defects using Molecular Static and climbing-Nudged Elastic Band methods. The results reveal that the vacancies energetically and kinetically tend to form and cluster around the GB plane due to the substantial reduction of their formation energies and migration barriers in layers close to the GB center and are immobile on the simulated time frame (~ps).

  1. Stimulated recovery of the optical transmission of PbWO 4 scintillation crystals for electromagnetic calorimeters after radiation damage

    Science.gov (United States)

    Dormenev, V.; Kuske, T.; Novotny, R. W.; Borisevich, A.; Fedorov, A.; Korjik, M.; Mechinski, V.; Missevitch, O.; Lugert, S.

    2010-11-01

    In this paper we describe the phenomenon of the stimulated recovery of radiation damage in lead tungstate scintillation crystals achieved via illumination by visible and infrared light. It allows fast and efficient in-situ recovery of the optical transmission either during beam-off periods or on-line during data accumulation. The application can substantially improve or extend the running period of the experiment by keeping the damage at a tolerable level.

  2. Protection of radiation induced DNA and membrane damages by total triterpenes isolated from Ganoderma lucidum (Fr.) P. Karst.

    Science.gov (United States)

    Smina, T P; Maurya, D K; Devasagayam, T P A; Janardhanan, K K

    2015-05-25

    The total triterpenes isolated from the fruiting bodies of Ganoderma lucidum was examined for its potential to prevent γ-radiation induced membrane damage in rat liver mitochondria and microsomes. The effects of total triterpenes on γ-radiation-induced DNA strand breaks in pBR 322 plasmid DNA in vitro and human peripheral blood lymphocytes ex vivo were evaluated. The protective effect of total triterpenes against γ-radiation-induced micronuclei formations in mice bone marrow cells in vivo were also evaluated. The results indicated the significant effectiveness of Ganoderma triterpenes in protecting the DNA and membrane damages consequent to the hazardous effects of radiation. The findings suggest the potential use of Ganoderma triterpenes in radio therapy. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  3. Monitoring Radiation Damage in the Vertex Locator and Top Pair Production in LHCb

    CERN Document Server

    Brown, Henry; Hutchcroft, David

    The Large Hadron Collider (LHC) is a proton-proton collider at the European Centre for Nuclear Research (CERN). The LHCb experiment is one of the four main experiments at the LHC. It is designed for the detection of $b\\bar{b}$ pairs produced in proton-proton collisions and to make precision measurements of $B$-mesons. The trigger level identification of $B$-mesons is provided by the Vertex Locator (VELO), which is the primary tracking detector of the experiment. Due to its proximity to the interaction point, the VELO is exposed to high levels of radiation damage. A new method of monitoring the damage is to perform current-voltage (IV) scans and to compare the results of these scans to laboratory tests on sample sensors. A method to perform the first $t\\bar{t}$ production measurement in the $\\eta>2$ range at the LHC, using a dilepton+$b$-jet channel, is also presented. A fiducial cross-section is obtained of $\\sigma_{\\mathrm{fid}}= 24.3^{+14.6}_{-9.7}\\mathrm{(stat.)}\\pm 6.9\\mathrm{(syst.)} \\pm 0.9 \\mathrm{(lum...

  4. 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...

  5. Survival, DNA Integrity, and Ultrastructural Damage in Antarctic Cryptoendolithic Eukaryotic Microorganisms Exposed to Ionizing Radiation

    Science.gov (United States)

    Pacelli, Claudia; Selbmann, Laura; Zucconi, Laura; Raguse, Marina; Moeller, Ralf; Shuryak, Igor; Onofri, Silvano

    2017-02-01

    Life dispersal between planets, planetary protection, and the search for biosignatures are main topics in astrobiology. Under the umbrella of the STARLIFE project, three Antarctic endolithic microorganisms, the melanized fungus Cryomyces antarcticus CCFEE 515, a hyaline strain of Umbilicaria sp. (CCFEE 6113, lichenized fungus), and a Stichococcus sp. strain (C45A, green alga), were exposed to high doses of space-relevant gamma radiation (60Co), up to 117.07 kGy. After irradiation survival, DNA integrity and ultrastructural damage were tested. The first was assessed by clonogenic test; viability and dose responses were reasonably described by the linear-quadratic formalism. DNA integrity was evaluated by PCR, and ultrastructural damage was observed by transmission electron microscopy. The most resistant among the tested organisms was C. antarcticus both in terms of colony formation and DNA preservation. Besides, results clearly demonstrate that DNA was well detectable in all the tested organisms even when microorganisms were dead. This high resistance provides support for the use of DNA as a possible biosignature during the next exploration campaigns. Implication in planetary protection and contamination during long-term space travel are put forward.

  6. Loranthus longiflorus protect central nervous system against oxidative damages of electromagnetic radiation on rat

    Directory of Open Access Journals (Sweden)

    Hemant Nagar

    2013-01-01

    Full Text Available Background: The interaction of mobile phone radio-frequency electromagnetic radiation (RF-EMR with the brain is a serious concern of our society. In this study, we aimed to experiment on the anti-oxidative property of a parasitic plant Loranthus longiflorus (Loranthaceae to protect central nervous system against oxidative damages of mobile phone electromagnetic field (EMF. Materials and Methods: Healthy male albino wistar rats were exposed to RF-EMR by giving 5 min calling/5 min interval for 1 hour per day for 2 months, keeping a GSM (0.9/1.8 GHz mobile phone in silent mode (no ring tone in the cage. After 15, 30, 45, 60 days exposure, three randomly picked animals from each group were tested with using behavioural model of CNS on rats. Results and Conclusion: Loranthus longiflorus bark extract could be effective in decreasing immobility (P < 0.05 and increased locomotor activity (P < 0.05. This result indicates the protective effect of Loranthus longiflorus bark against EMF induced oxidative damage of central nervous system.

  7. Black tea extract: a supplementary antioxidant in radiation-induced damage to DNA and normal lymphocytes.

    Science.gov (United States)

    Ghosh, Debjani; Pal, Sandip; Saha, Chabita; Chakrabarti, Amit Kumar; Datta, Salil C; Dey, Subrata Kumar

    2012-01-01

    Myriad research has contributed significantly toward the understanding and identification of health benefits stemming from tea polyphenols and many other naturally occurring flavonoids present in fruits and vegetables. These flavonoids are known to mitigate reactive oxygen species-induced damage by scavenging them. In this study, hot-water black tea extract rich in flavonoids is evaluated as a supplementary antioxidant. The antioxidant efficacy of black tea extract was investigated by evaluating radioprotection conferred to pBR322 DNA, calf thymus DNA, and normal lymphocytes during gamma irradiation. The protection was measured by gel electrophoresis, fluorimetric study, cell viability assay, cytokinesis-blocked micronuclei assay, and comet assay. The 2,2-diphenyl-1-picrylhydrazyl scavenging ability of the tea extract used increased in a dose-dependent manner (IC50: 182.45 µg/mL). Positive correlation of radioprotection with antioxidant activity of black tea extract was observed in all systems. Maximum protection against radiation-induced damage was observed in pBR322 DNA and calf thymus DNA at ≥200 µg/mL of black tea extract. At a dose of black tea extract as low as 5 µg/mL, efficient radioprotection was observed in normal lymphocytes, which is encouraging and can be tested in the future as a natural antioxidant supplement during radiotherapy.

  8. Radiation response of alloy T91 at damage levels up to 1000 peak dpa

    Energy Technology Data Exchange (ETDEWEB)

    Gigax, J. G.; Chen, T.; Kim, Hyosim; Wang, J.; Price, L. M.; Aydogan, E.; Maloy, S. A.; Schreiber, D. K.; Toloczko, M. B.; Garner, F. A.; Shao, Lin

    2016-12-01

    Ferritic/martensitic alloys are required for advanced reactor components to survive 500e600 neutroninduced dpa. Ion-induced void swelling of ferritic/martensitic alloy T91 in the quenched and tempered condition has been studied using a defocused, non-rastered 3.5 MeV Fe-ion beam at 475 C to produce damage levels up to 1000 peak displacements per atom (dpa). The high peak damage level of 1000 dpa is required to reach 500e600 dpa level due to injected interstitial suppression of void nucleation in the peak dpa region, requiring data extraction closer to the surface at lower dpa levels. At a relatively low peak damage level of 250 dpa, voids began to develop, appearing first in the near-surface region. With increasing ion fluence, swelling was observed deeper in the specimen, but remained completely suppressed in the back half of the ion range, even at 1000 peak dpa. The local differences in dpa rate in the front half of the ion range induce an “internal temperature shift” that strongly influences the onset of swelling, with shorter transient regimes resulting from lower dpa rates, in agreement not only with observations in neutron irradiation studies but also in various ion irradiations. Swelling was accompanied by radiation-induced precipitation of Cu-rich and Si, Ni, Mn-rich phases were observed by atom probe tomography, indicating concurrent microchemical evolution was in progress. In comparison to other ferritic/martensitic alloys during ion irradiation, T91 exhibits good swelling resistance with a swelling incubation period of about 400 local dpa.

  9. Effects of radiation on levels of DNA damage in normal non-adjacent mucosa from colorectal cancer cases.

    LENUS (Irish Health Repository)

    Sheridan, Juliette

    2013-03-01

    Defects in DNA repair pathways have been linked with colorectal cancer (CRC). Adjuvant radiotherapy has become commonplace in the treatment of rectal cancer however it is associated with a higher rate of second cancer formation. It is known that radiation results in DNA damage directly or indirectly by radiation-induced bystander effect (RIBE) by causing double-strand breaks (DSBs). The majority of work in RIBE has been performed in cell lines and limited studies have been in or ex vivo.

  10. Strength loss in MA-MOX green pellets from radiation damage to binders

    Science.gov (United States)

    Lessing, Paul A.; Cannon, W. Roger; Egeland, Gerald W.; Zuck, Larry D.; Jewell, James K.; Akers, Douglas W.; Groenewold, Gary S.

    2013-06-01

    The fracture strength of green Minor Actinides (MA)-MOX pellets containing 75 wt.% DUO2, 20 wt.% PuO2, 3 wt.% AmO2 and 2 wt.% NpO2 was studied as a function of storage time, after mixing with the binder and before sintering, to test the effect of radiation damage on binders. Fracture strength degraded continuously over the 10 days of the study for all three binders studied: PEG binder (Carbowax 8000), microcrystalline wax (Mobilcer X) and styrene-acrylic copolymer (Duramax B1022) but the fracture strength of Duramax B1022 degraded the least. For instance, for several hours after mixing Carbowax 8000 with MA-MOX, the fracture strength of a pellet was reasonably high and pellets were easily handled without breaking but the pellets were too weak to handle after 10 days. Strength measured using diametral compression test showed that strength degradation was more rapid in pellets containing 1.0 wt.% Carbowax PEG 8000 compared to those containing only 0.2 wt.%, suggesting that irradiation not only left the binder less effective but also reduced the pellet strength. In contrast the strength of pellets containing Duramax B1022 degraded very little over the 10 days period. It was suggested that the styrene portion present in the Duramax B1022 copolymer provided the radiation resistance.

  11. Strength Loss in MA-MOX Green Pellets from Radiation Damage to Binders

    Energy Technology Data Exchange (ETDEWEB)

    Paul A. Lessing; W.R. Cannon; Gerald W. Egeland; Larry D. Zuck; James K. Jewell; Douglas W. Akers; Gary S. Groenewold

    2013-06-01

    The fracture strength of green Minor Actinides (MA)-MOX pellets containing 75 wt.% DUO2, 20 wt. % PuO2, 3 wt. % AmO2 and 2 wt. % NpO2 was studied as a function of storage time, after mixing in the binder and before sintering, to test the effect of radiation damage on binders. Fracture strength degraded continuously over the 10 days of the study for all three binders studied: PEG binder (Carbowax 8000), microcrystalline wax (Mobilcer X) and Styrene-acrylic copolymer (Duramax B1022) but the fracture strength of Duramax B1022 degraded the least. For instance, for several hours after mixing Carbowax 8000 with MA MOX, the fracture strength of a pellet was reasonably high and pellets were easily handled without breaking but the pellets were too weak to handle after 10 days. Strength measured using diametral compression test showed strength degradation was more rapid in pellets containing 1.0 wt. % Carbowax PEG 8000 compared to those containing only 0.2 wt. %, suggesting that irradiation not only left the binder less effective but also reduced the pellet strength. In contrast the strength of pellets containing Duramax B1022 degraded very little over the 10 day period. It was suggested that the styrene portion of the Duramax B1022 copolymer provided the radiation resistance.

  12. Strength loss in MA-MOX green pellets from radiation damage to binders

    Energy Technology Data Exchange (ETDEWEB)

    Lessing, Paul A. [Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Cannon, W. Roger, E-mail: wrogercannon@gmail.com [Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Egeland, Gerald W.; Zuck, Larry D.; Jewell, James K.; Akers, Douglas W.; Groenewold, Gary S. [Idaho National Laboratory, Idaho Falls, ID 83415 (United States)

    2013-06-15

    The fracture strength of green Minor Actinides (MA)-MOX pellets containing 75 wt.% DUO{sub 2}, 20 wt.% PuO{sub 2}, 3 wt.% AmO{sub 2} and 2 wt.% NpO{sub 2} was studied as a function of storage time, after mixing with the binder and before sintering, to test the effect of radiation damage on binders. Fracture strength degraded continuously over the 10 days of the study for all three binders studied: PEG binder (Carbowax 8000), microcrystalline wax (Mobilcer X) and styrene–acrylic copolymer (Duramax B1022) but the fracture strength of Duramax B1022 degraded the least. For instance, for several hours after mixing Carbowax 8000 with MA-MOX, the fracture strength of a pellet was reasonably high and pellets were easily handled without breaking but the pellets were too weak to handle after 10 days. Strength measured using diametral compression test showed that strength degradation was more rapid in pellets containing 1.0 wt.% Carbowax PEG 8000 compared to those containing only 0.2 wt.%, suggesting that irradiation not only left the binder less effective but also reduced the pellet strength. In contrast the strength of pellets containing Duramax B1022 degraded very little over the 10 days period. It was suggested that the styrene portion present in the Duramax B1022 copolymer provided the radiation resistance.

  13. Cooling out the radiation damage on the XMM-Newton EPIC MOS CCDs

    Energy Technology Data Exchange (ETDEWEB)

    Abbey, A.F. E-mail: afa@star.le.ac.uk; Bennie, P.J.; Turner, M.J.L.; Altieri, B.; Rives, S

    2003-11-01

    The X-ray astronomy satellite XMM-Newton has been in an orbit taking it through the trapped radiation belts and direct solar proton flux during the peak of the current solar cycle for over two and a half years. The MOS CCD detectors (E2 V CCD22's) have degraded in charge transfer efficiency (CTE) as a result of damage created by high energy protons. Corrections for CTE in ground software have managed to restore most of the energy loss generated by the trapping sites, but the detector energy resolution has widened due to imperfect correction methods and the statistical noise generated by charge trapping. The detectors have been at -100 deg. C since launch, and they are qualified to operate down to -130 deg. C. Similar CCDs have been irradiated on the ground with 10 MeV protons and it was believed that the devices in orbit, although irradiated by much lower fluxes for longer times should exhibit the same improved CTE at lower temperatures. There was also concern that contrary to test devices on the ground, the devices in orbit had been almost continually cold for over 2 years and many bright pixels had developed giving a signal even at -100 deg. C, due possibly to radiation and the impact of micro-meteoroids. Cooling the CCDs in XMM to -120 deg. C demonstrated the expected improvement, and we intend to run both MOS cameras at the new temperature later in the year.

  14. Alterations in phosphate metabolism during cellular recovery of radiation damage in yeast

    Energy Technology Data Exchange (ETDEWEB)

    Holahan, P.K.; Knizner, S.A.; Gabriel, C.M.; Swenberg, C.E.

    1988-10-01

    The authors examined alterations in phosphate pools during cellular recovery from radiation damage in intact, wild-type diploid yeast cells using /sup 31/P nuclear magnetic resonance (NMR) spectroscopy. Concurrent cell survival analysis was determined following exposure to /sup 60/Co ..gamma..-irradiation. Cells held in citrate-buffered saline (CBS) showed increased survival with increasing time after irradiation (liquid holding recovery, LHR) with no further recovery beyond 48 h. Addition of 100 mmol dm/sup -3/ glucose to the recovery medium resulted in greater recovery. In the presence of 5 mmol dm/sup /-/sup 3/ 2-deoxyglucose (2-DG), LHR was completely inhibited. NMR analyses were done on cells perfused in agarose threads and maintained under conditions similar to those in the survival studies. ATP was observable by NMR only when glucose was present in the recovery medium. In control cells, ATP concentrations increased and plateaued with increasing recovery time. With increasing radiation dose the increase in ATP was of lesser magnitude, and after 2000 Gy no increase was observed.

  15. Radiation damage in InGaAs photodiodes by 1 MeV fast neutrons

    CERN Document Server

    Ohyama, H; Vanhellemont, J; Takami, Y; Sunaga, H

    1998-01-01

    Irradiation damage in In sub 0 sub . sub 5 sub 3 Ga sub 0 sub . sub 4 sub 7 As p-i-n photodiodes by 1 MeV fast neutrons has been studied as a function of fluence for the first time, and the results are discussed in this paper. The degradation of the electrical and optical performance of diodes increases with increasing fluence. The induced lattice defects in the In sub 0 sub . sub 5 sub 3 Ga sub 0 sub . sub 4 sub 7 As epitaxial layers and the InP substrate are studied by Deep Level Transient Spectroscopy (DLTS) methods. In the In sub 0 sub . sub 5 sub 3 Ga sub 0 sub . sub 4 sub 7 As epitaxial layers, hole and electron capture levels are induced by irradiation. The influence of the type of radiation source on the device degradation is then discussed by comparison to 1 MeV electrons with respect to the numbers of knock-on atoms and the nonionizing energy loss (NIEL). The radiation source dependence of performance degradation is attributed to the difference of mass between the two irradiating particles and the p...

  16. Sunlight technologies for photochemical deactivation of organic pollutants in water

    Energy Technology Data Exchange (ETDEWEB)

    Acher, A.; Fischer, E.; Tornheim, R. [The Volcani Center, Inst. of Soils and Water, Bet Dagan (Israel); Manor, Y. [Sheba Medical Center, Central Virology Lab., Ramat Gan (Israel)

    1997-12-31

    Sensitized-photochemical oxidation methods aimed at use in water treatment technologies for deactivation of biotic (microorganisms) and/or of xenobiotic (pesticides) pollutants in water were developed using global solar radiation or concentrated sunlight (up to 250 suns). The solar global radiation was used either for detoxification of industrial waste water from a pesticide factory to allow their discharge into the urban sewer, or for disinfection of domestric effluents to be used in crop irrigation. The disinfection process was eventually carried out in an experimental pilot-scale plant, capable of disinfection up to 50 m{sup 3}/h of effluent supplied by an activated sludge sewage treatment plant located in Tel-Aviv area. The treated effluents did not show any regrowth of the microorganisms during 7 days. The solar concentrated radiation experiments performed using facilities of the Sun Tower of The Weizman Institute of Science, Rehovot. The concentrated sunlight was provided by different combination of several computer controlled heliostates, up to 8, that track the sun and focus the received sunlight onto the target situated on the roof of the sun-tower. The sunlight intensities measured on the target reached up to 200 kW/m{sup 2}. The experiments were performed either batch- or continuous-wise. The water-samples exposed to disinfection were the above effluent, filtered and supplemented with vaccine strain poliovirus or with different concentrations of an industrial potential pollutant (bromacil), MB 2 mg/L and two concentrations of dissolved oxygen (8.0 or 40.0 mg O{sub 2}/L). An exposure time of 2-3 seconds at 150 kW/m{sup 2} was decreased the microorganisms alive (counts) by five orders of magnitude. A comparison between the two above water treatment technologies is presented. (orig./SR)

  17. Potential of Piper guineense and Aframomum longiscapum to reduce radiation induced hepatic damage in male Wistar rats.

    Science.gov (United States)

    Nwozo, S O; Okameme, P E; Oyinloye, B E

    2012-01-01

    The ameliorative effect of aqueous extracts of Piper guineense and Aframomum longiscapum on radiation-induced hepatic damage was evaluated. Rats were treated with a single dose of 600 rads (6 Gy) y-radiation to induce hepatic damage. Aqueous extracts of Piper guineense and Aframomum longiscapum (200 and 400 mg/kg b. wt) were administered orally to rats for two weeks prior to radiation and four weeks after radiation. Hepatic malondialdehyde (MDA), glutathione (GSH) levels and glutathione peroxidase (GPx) and catalase (CAT) activities were determined for their antioxidant capacity. The activities of serum markers such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and the histological changes were examined to evaluate potential ameliorative effects. Results from this study confirmed that exposure of animals to radiation led to induction of lipid peroxidation (LPO), reduced the level of GSH as well as CAT and GPx activities while simultaneously a significant elevation in the activities of serum ALT and AST was observed. Administration of varying doses of P.G. and A.L. before and after irradiation inhibited the elevated levels of LPO, restored the GSH level and enhanced CAT and GPx activities as well as significantly decreased the elevated levels of serum ALT and AST activities. This findings demonstrated that aqueous extracts of Piper guineense and Aframomum longiscapum might mitigate the liver gamma-radiation-induced damage probably by increasing antioxidant activities.

  18. Radiation damage evaluation on concrete within a facility for Selective Production of Exotic Species (SPES Project), Italy.

    Science.gov (United States)

    Pomaro, B; Salomoni, V A; Gramegna, F; Prete, G; Majorana, C E

    2011-10-30

    Concrete is commonly used as a biological shield against nuclear radiation. As long as, in the design of nuclear facilities, its load carrying capacity is required together with its shielding properties, changes in the mechanical properties due to nuclear radiation are of particular significance and may have to be taken into account in such circumstances. The study presented here allows for reaching first evidences on the behavior of concrete when exposed to nuclear radiation in order to evaluate the consequent effect on the mechanical field, by means of a proper definition of the radiation damage, strictly connected with the strength properties of the building material. Experimental evidences on the decay of the mechanical modulus of concrete have allowed for implementing the required damage law within a 3D F.E. research code which accounts for the coupling among moisture, heat transfer and the mechanical field in concrete treated as a fully coupled porous medium. The development of the damage front in a concrete shielding wall is analyzed under neutron radiation and results within the wall thickness are reported for long-term radiation spans and several concrete mixtures in order to discuss the resulting shielding properties.

  19. Recovery From Radiation-induced Bone Marrow Damage by HSP25 Through Tie2 Signaling

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hae-June [Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Kwon, Hee-Chung [Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Chung, Hee-Yong [College of Medicine, Hanyang University, Seoul (Korea, Republic of); Lee, Yoon-Jin [Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Lee, Yun-Sil, E-mail: yslee0425@ewha.ac.kr [College of Pharmacy and Division of Life and Pharmaceutical Sciences, Ewha Woman' s University, Seoul (Korea, Republic of)

    2012-09-01

    Purpose: Whole-body radiation therapy can cause severe injury to the hematopoietic system, and therefore it is necessary to identify a novel strategy for overcoming this injury. Methods and Materials: Mice were irradiated with 4.5 Gy after heat shock protein 25 (HSP25) gene transfer using an adenoviral vector. Then, peripheral blood cell counts, histopathological analysis, and Western blotting on bone marrow (BM) cells were performed. The interaction of HSP25 with Tie2 was investigated with mouse OP9 and human BM-derived mesenchymal stem cells to determine the mechanism of HSP25 in the hematopoietic system. Results: HSP25 transfer increased BM regeneration and reduced apoptosis following whole-body exposure to ionizing radiation (IR). The decrease in Tie2 protein expression that followed irradiation of the BM was blocked by HSP25 transfer, and Tie2-positive cells were more abundant among the BM cells of HSP25-transferred mice, even after IR exposure. Following systemic RNA interference of Tie2 before IR, HSP25-mediated radioprotective effects were partially blocked in both mice and cell line systems. Stability of Tie2 was increased by HSP25, a response mediated by the interaction of HSP25 with Tie2. IR-induced tyrosine phosphorylation of Tie2 was augmented by HSP25 overexpression; downstream events in the Tie2 signaling pathway, including phosphorylation of AKT and EKR1/2, were also activated. Conclusions: HSP25 protects against radiation-induced BM damage by interacting with and stabilizing Tie2. This may be a novel strategy for HSP25-mediated radioprotection in BM.

  20. Detection of late radiation damage on left atrial fibrosis using cardiac late gadolinium enhancement magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Y. Jessica Huang, PhD

    2016-04-01

    Conclusions: With LGE-MRI and 3-dimensional dose mapping on the treatment planning system, it is possible to define subclinical cardiac damage and distinguish intrinsic cardiac tissue change from radiation induced cardiac tissue damage. Imaging myocardial injury secondary to EBRT using MRI may be a useful modality to follow cardiac toxicity from EBRT and help identify individuals who are more susceptible to EBRT damage. LGE-MRI may provide essential information to identify early screening strategy for affected cancer survivors after EBRT treatment.

  1. Mobile phone radiation induces reactive oxygen species production and DNA damage in human spermatozoa in vitro.

    Directory of Open Access Journals (Sweden)

    Geoffry N De Iuliis

    Full Text Available BACKGROUND: In recent times there has been some controversy over the impact of electromagnetic radiation on human health. The significance of mobile phone radiation on male reproduction is a key element of this debate since several studies have suggested a relationship between mobile phone use and semen quality. The potential mechanisms involved have not been established, however, human spermatozoa are known to be particularly vulnerable to oxidative stress by virtue of the abundant availability of substrates for free radical attack and the lack of cytoplasmic space to accommodate antioxidant enzymes. Moreover, the induction of oxidative stress in these cells not only perturbs their capacity for fertilization but also contributes to sperm DNA damage. The latter has, in turn, been linked with poor fertility, an increased incidence of miscarriage and morbidity in the offspring, including childhood cancer. In light of these associations, we have analyzed the influence of RF-EMR on the cell biology of human spermatozoa in vitro. PRINCIPAL FINDINGS: Purified human spermatozoa were exposed to radio-frequency electromagnetic radiation (RF-EMR tuned to 1.8 GHz and covering a range of specific absorption rates (SAR from 0.4 W/kg to 27.5 W/kg. In step with increasing SAR, motility and vitality were significantly reduced after RF-EMR exposure, while the mitochondrial generation of reactive oxygen species and DNA fragmentation were significantly elevated (P<0.001. Furthermore, we also observed highly significant relationships between SAR, the oxidative DNA damage bio-marker, 8-OH-dG, and DNA fragmentation after RF-EMR exposure. CONCLUSIONS: RF-EMR in both the power density and frequency range of mobile phones enhances mitochondrial reactive oxygen species generation by human spermatozoa, decreasing the motility and vitality of these cells while stimulating DNA base adduct formation and, ultimately DNA fragmentation. These findings have clear implications

  2. Dislocations and radiation damage in {alpha}-uranium; Dislocations et effets des radiations dans l'uranium {alpha}

    Energy Technology Data Exchange (ETDEWEB)

    Leteurtre, J. [Commissariat a l' Energie Atomique, 92 - Fontenay-Aux-Roses (France). Centre d' Etudes Nucleaires

    1968-07-01

    Dislocations in {alpha}-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 {alpha}-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) [French] Ce travail est une etude par microscopie electronique des dislocations induites dans l'uranium {alpha}, soit par deformation plastique, soit par irradiation. Une methode de preparation des lames minces a basse temperature (-110 deg. C) a ete mise au point. Les vecteurs de Burgers des diverses dislocations de macles de ce metal ont ete definis. Les interactions glissements- maclages sont etudiees experimentalement et theoriquement. Des echantillons irradies a divers taux de combustion ont ete examines. Pour expliquer nos resultats micrographiques, et aussi l'ensemble des informations recueillies dans la litterature concernant l'endommagement par irradiation de l'uranium-{alpha}, nous proposons un modele coherent de l'effet des fragments de fission dans ce metal. L'influence des parametres: temperature, densite de dislocations, impuretes est analysee. Le nombre de defauts ponctuels crees

  3. Vascular and nerval damage after intraoperative radiation therapy of the liver hilum in a large animal model.

    Science.gov (United States)

    Juntermanns, Benjamin; Grabellus, Florian; Zhang, Hongwei; Radunz, Sonia; Bernheim, Johannes; Fingas, Christian Dominik; Sauerwein, Wolfgang; Paul, Andreas; Kaiser, Gernot Maximilian

    2014-06-01

    It has been demonstrated that intraoperative radiotherapy is a therapeutic option for patients suffering from perihilar cholangiocarcinoma. Aim of our study was to investigate vascular and nerve damages after irradiation of the liver hilum in a pig model. Twenty-four pigs underwent central bile duct resection followed by biliodigestive anastomosis. Nine pigs underwent this surgical procedure alone (group 1). Ten pigs were treated with additional intraoperative radiation therapy (IORT) of 20Gy to the liver hilum (group 2). And five pigs received operation and IORT with 40Gy to the area of anastomosis (group 3). Six weeks after operation and treatment the animals were sacrificed and histopathological examination was performed. Histology showed no vascular or nerve damage in non-irradiated perihilar tissue. Significant changes of nerve structures occurred, as well as vascular damage in large and even more in small hilar arteries in the irradiated neighboring liver tissue. In detail for small hilar arteries: intima proliferation (p ≤ .0001), endothelial swelling (p ≤ .0001), fibrinoid arterial wall necrosis (p ≤ .0001), and arterial thrombosis (p = .0079) were detected. Venous vessels did not show significant dose dependant cell damage. Overall, 20Gy as a single dose application during operation showed similar damage to vessels and nerves compared to 40Gy. A radiation dosage of 20Gy seems to be sufficient to induce necrosis due to vascular and nerve damage in potential malignant liver tissue with acceptable damage to surrounding tissue. Perineural invaded tumor cells might be diminished due to IORT.

  4. Sunlight inactivation of faecal bacteria in waste stabilization ponds in a Sahelian region (Ouagadougou, Burkina Faso)

    Energy Technology Data Exchange (ETDEWEB)

    Maiga, Y.; Denyigba, K.; Wethe, J.; Ouattara, A. S.

    2009-07-01

    Waste stabilization ponds (WSPs) are an appropriate sewage treatment system for developing countries in Sahelian regions. Several studies on wastewater treatment in WSPs have shown that solar radiation is a major factor in the inactivation of faecal indicator, and that sunlight acts on interaction with other factors including dissolved oxygen (DO) and pH. However, the inactivation by sunlight is limited by the reduction of light penetration in ponds. (Author)

  5. A molecular dynamics simulation of DNA damage induction by ionizing radiation

    Science.gov (United States)

    Abolfath, Ramin M.; Carlson, David J.; Chen, Zhe J.; Nath, Ravinder

    2013-10-01

    We present a multi-scale simulation of the early stage of DNA damages by the indirect action of hydroxyl (•OH) free radicals generated by electrons and protons. The computational method comprises of interfacing the Geant4-DNA Monte Carlo with ReaxFF molecular dynamics software. A clustering method was employed to map the coordinates of •OH-radicals extracted from the ionization-track-structures onto nano-meter simulation voxels filled with DNA and water molecules. The molecular dynamics simulation provides the time-evolution and chemical reactions in individual simulation voxels as well as the energy-landscape accounted for the DNA-•OH chemical reaction that is essential for the first-principle enumeration of hydrogen abstractions, chemical bond breaks, and DNA-lesions induced by collection of ions in clusters less than the critical dimension which is approximately 2-3 Å. We show that the formation of broken bonds leads to DNA-base and backbone damages that collectively propagate to DNA single and double-strand breaks. For illustration of the methodology, we focused on particles with an initial energy of 1 MeV. Our studies reveal a qualitative difference in DNA damage induced by low energy electrons and protons. Electrons mainly generate small pockets of •OH-radicals, randomly dispersed in the cell volume. In contrast, protons generate larger clusters along a straight-line parallel to the direction of the particle. The ratio of the total DNA double-strand breaks induced by a single proton and electron track is determined to be ≈4 in the linear scaling limit. In summary, we have developed a multi-scale computational model based on first-principles to study the interaction of ionizing radiation with DNA molecules. The main advantage of our hybrid Monte Carlo approach using Geant4-DNA and ReaxFF is the multi-scale simulation of the cascade of both physical and chemical events which result in the formation of biological damage. The tool developed in this

  6. Varying relationship between 25-hydroxy-vitamin D, high density lipoprotein cholesterol, and serum 7-dehydrocholesterol reductase with sunlight exposure.

    Science.gov (United States)

    Patwardhan, Vivek G; Khadilkar, Anuradha V; Chiplonkar, Shashi A; Mughal, Zulf M; Khadilkar, Vaman V

    2015-01-01

    Cholesterol and cholecalciferol are synthesized from a common substrate 7-dehydrocholesterol. 7-dehydrocholesterol is converted to cholesterol by 7-dehydrocholesterol reductase enzyme (DHCR7) and to cholecalciferol by ultraviolet B radiation from sunlight. To examine the effect of sunlight exposure and serum DHCR7 levels on cholecalciferol and cholesterol levels and studying any interrelationship. In a cross-sectional observational study, 307 apparently healthy men (aged 40-60 years) were assessed for sunlight exposure, lipid levels, serum DHCR7, 25 hydroxyvitamin D (25(OH)D), body composition, and dietary milk calcium intake. Vitamin D deficiency (25(OH)D sunlight exposure (P sunlight exposure (sunlight exposure (1-2 h/d), there was no significant association. However, with higher sunlight exposure (>2 h/d), serum 25(OH)D concentrations were significantly negatively associated with HDL-C (P sunlight exposure, an inverse significant relationship was observed between 25(OH)D and serum DHCR7 (P sunlight exposure, no significant relationship was seen. 25(OH)D seems to show a varying relationship with HDL-C and serum DHCR7 at different durations of sunlight exposure. Copyright © 2015 National Lipid Association. Published by Elsevier Inc. All rights reserved.

  7. Radiation damage effects on the silicon microstrip detector in E789 - a fixed target experiment at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Kapustinsky, J.S.; Apolinski, M.; Boissevain, J.; Brown, C.N.; Brown, G.; Carey, T.A.; Chen, Y.C.; Childers, R.; Cooper, W.E.; Darden, C.W.; Gidal, G.; Glass, H.D.; Gounder, K.N.; Ho, P.M.; Isenhower, D.; Jansen, D.M.; Jeppesen, R.; Kaplan, D.M.; Kiang, G.C.; Kowitt, M.S.; Lane, D.W.; Lederman, L.; Leitch, M.J.; Lillberg, J.W.; Luebke, W.; Luk, K.B.; Martin, V.M.; McGaughey, P.L.; Mishra, C.S.; Moss, J.M.; Peng, J.C.; Preston, R.S.; Pripstein, D.; Sa, J.; Sadler, M.; Schnathorst, R.; Schub, M.H.; Schwint, R.; Snodgrass, D.; Tanikella, V.N.; Teng, P.K.; Wilson, J.W. (Los Alamos National Lab., Los Alamos, NM (United States) Northern Illinois Univ., Dekalb, IL (United States) Fermi National Accelerator Lab., Batavia, IL (United States) Abilene Christian Univ., Abilene, TX (United States) Academia Sinica (Taiwan, Province of China) National Cheng Kung Univ., Tainan (Taiwan, Province of China) Univ. of South Carolina, Columbia, SC (United States) Lawrence Berkeley Lab., CA (United States)

    1993-05-01

    A Silicon Microstrip Spectrometer has been installed and successfully operated in experiment E789 at Fermilab. The main physics goal of the experiment is to search for charged particle decays of B and D Mesons. Damage effects due to ionizing radiation exposure to the silicon during the experiment are reported. (orig.)

  8. Nanoscale imaging of untreated mammalian cells in a medium with low radiation damage using scanning electron-assisted dielectric microscopy

    Science.gov (United States)

    Okada, Tomoko; Ogura, Toshihiko

    2016-01-01

    Imaging of untreated living cells in a medium at a nanometre-scale resolution under physiological conditions is a significant challenge. Scanning electron microscopy (SEM) is widely used to observe cells in various atmospheric holders or special equipment. However, untreated biological specimens in aqueous solution generally incur heavy radiation damage from the direct electron beam (EB); and these images exhibit very poor contrast. Therefore, a new method for generating high-contrast images of living cells under physiological conditions without radiation damage has been strongly desired. Here, we demonstrate the first nanoscale observation of living cultured mammalian cells using our newly developed scanning-electron assisted dielectric microscopy (SE-ADM) method with a culture dish holder. Using the difference in relative permittivity between water and specimens, our SE-ADM system aids in the visualisation of untreated biological samples in aqueous solution. In addition, specimens incurred only a low level of radiation damage because the tungsten (W)-coated silicon nitride (SiN) film absorbs irradiated electrons. Untreated cells and organelles are clearly visible in high-contrast and high-resolution images without staining and fixation. Furthermore, our method enables the detection of changes in organelle structures within cells via time-lapse imaging with minimal radiation damage. PMID:27375121

  9. Mobilization of bone marrow stem cells by granulocyte colony-stimulating factor ameliorates radiation-induced damage to salivary glands

    NARCIS (Netherlands)

    Lombaert, IMA; Wierenga, PK; Kok, T; Kampinga, HH; deHaan, G; Coppes, RP

    2006-01-01

    Purpose: One of the major reasons for failure of radiotherapeutic cancer treatment is the limitation in dose that can be applied to the tumor because of coirradiation of the normal healthy tissue. Late radiation-induced damage reduces the quality of life of the patient and may even be life threateni

  10. Nanoscale imaging of untreated mammalian cells in a medium with low radiation damage using scanning electron-assisted dielectric microscopy

    Science.gov (United States)

    Okada, Tomoko; Ogura, Toshihiko

    2016-07-01

    Imaging of untreated living cells in a medium at a nanometre-scale resolution under physiological conditions is a significant challenge. Scanning electron microscopy (SEM) is widely used to observe cells in various atmospheric holders or special equipment. However, untreated biological specimens in aqueous solution generally incur heavy radiation damage from the direct electron beam (EB); and these images exhibit very poor contrast. Therefore, a new method for generating high-contrast images of living cells under physiological conditions without radiation damage has been strongly desired. Here, we demonstrate the first nanoscale observation of living cultured mammalian cells using our newly developed scanning-electron assisted dielectric microscopy (SE-ADM) method with a culture dish holder. Using the difference in relative permittivity between water and specimens, our SE-ADM system aids in the visualisation of untreated biological samples in aqueous solution. In addition, specimens incurred only a low level of radiation damage because the tungsten (W)-coated silicon nitride (SiN) film absorbs irradiated electrons. Untreated cells and organelles are clearly visible in high-contrast and high-resolution images without staining and fixation. Furthermore, our method enables the detection of changes in organelle structures within cells via time-lapse imaging with minimal radiation damage.

  11. Annealing of radiation damage in zircons from Apollo 14 impact breccia 14311: Implications for the thermal history of the breccia

    Science.gov (United States)

    Pidgeon, R. T.; Merle, R. E.; Grange, M. L.; Nemchin, A. A.; Whitehouse, M. J.

    2016-01-01

    Impact breccia 14311, was collected from the Apollo 14 landing site as a potential sample of the underlying Fra Mauro Formation. Published zircon U-Pb ages of >4000 Ma date the source material of the breccia and the apatite U-Pb age of ~3940 Ma is interpreted as dating thermal resetting of the apatite U-Pb systems. In this contribution we present new age information on the late stage thermal history of the breccia based on the annealing of radiation damage in the zircons. From Raman spectroscopic determination of the radiation damage within SIMS analytical spots on the zircons and the U and Th concentrations determined on these spots, we demonstrate that the radiation damage in the zircons has been annealed and we estimate the age of annealing at 3410 ± 80 Ma. This age is interpreted as a cooling age following heating of the breccia to above the annealing temperature of ~230 °C for stage 1 radiation damage in zircon, but below the temperature needed to reset the U-Pb system of apatite (~500 °C). It is proposed that this thermal event was associated with the prolonged period of Mare volcanism, from 3150 to 3750 Ma, that generated massive basalt flows in the vicinity of the sample location.

  12. SOLAR RADIATION AND INDUCTION OF DNA DAMAGE, MUTATIONS AND SKIN CANCERS.

    Energy Technology Data Exchange (ETDEWEB)

    SETLOW,R.B.

    2007-05-10

    An understanding of the effects of sunlight on human skin begins with the effects on DNA and extends to cells, animals and humans. The major DNA photoproducts arising from UVB (280-320 nm) exposures are cyclobutane pyrimidine dimers. If unrepaired, they may kill or mutate cells and result in basal and squamous cell carcinomas. Although UVA (320-400 nm) and visible wavelengths are poorly absorbed by DNA, the existing data indicate clearly that exposures to these wavelengths are responsible, in an animal model, for {approx}95 % of the incidence of cutaneous malignant melanoma (CMM). Six lines of evidence, to be discussed in detail, support the photosensitizing role of melanin in the induction of this cancer. They are: (1) Melanomas induced in backcross hybrids of small tropical fish of the genus Xiphophorus, exposed to wavelengths from 302-547 nm, indicate that {approx}95% of the cancers induced by exposure to sunlight would arise from UVA + visible wavelengths; (2) The action spectrum for inducing melanin-photosensitized oxidant production is very similar to the spectrum for inducing melanoma; (3) Albino whites and blacks, although very sensitive to sunburn and the sunlight induction of non-CMM, have very low incidences of CMM; (4) The incidence of CMM as a function of latitude is very similar to that of UVA, but not UVB; (5) Use of UVA-exposing sun-tanning parlors by the young increases the incidence rate of CMM and (6) Major mutations observed in CMM are not UVB-induced.

  13. Effect of proton and electron-irradiation intensity on radiation-induced damages in silicon bipolar transistors

    Energy Technology Data Exchange (ETDEWEB)

    Bannikov, Yu.A.; Gorin, B.M.; Kozhevnikov, V.P.; Mikhnovich, V.V.; Gusev, L.I.

    1981-11-01

    The increase of radiation-induced damages of bipolar n-p-n transistors 8-12 times with the irradiation intensity decrease by protons from 4.07x1010 to 2.5x107 cm-2 x c-1 has been found experimentally. Damages of p-n-p transistors vary in the opposite way - they are decreased 2-3 times with the irradiation intensity decrease within the same limits. The dependence of damages on intensity of proton irradiation occurs at the dose rate by three orders less than it has been observed for electron irradiation. The results obtained are explained by the dependence of radiation defect formation reactions on charge state of defects with account for the role of formation of disordering regions upon proton irradiation.

  14. Combined Bulk and Surface Radiation Damage Effects at Very High Fluences in Silicon Detectors: Measurements and TCAD Simulations

    CERN Document Server

    Moscatelli, F; Morozzi, A; Mendicino, Roberto; Betta, G -F Dalla; Bilei, G M

    2016-01-01

    In this work we propose a new combined TCAD radiation damage modelling scheme, featuring both bulk and surface radiation damage effects, for the analysis of silicon detectors aimed at the High Luminosity LHC. In particular, a surface damage model has been developed by introducing the relevant parameters (NOX, NIT) extracted from experimental measurements carried out on p-type substrate test structures after gamma irradiations at doses in the range 10-500 Mrad(Si). An extended bulk model, by considering impact ionization and deep-level cross-sections variation, was included as well. The model has been validated through the comparison of the simulation findings with experimental measurements carried out at very high fluences (2 10^16 1 MeV equivalent n/cm^2) thus fostering the application of this TCAD approach for the design and optimization of the new generation of silicon detectors to be used in future HEP experiments.

  15. Combined Bulk and Surface Radiation Damage Effects at Very High Fluences in Silicon Detectors: Measurements and TCAD Simulations

    CERN Document Server

    Moscatelli, F; Morozzi, A; Mendicino, R; Dalla Betta, G F; Bilei, G M

    2016-01-01

    In this work we propose a new combined TCAD radiation damage modelling scheme, featuring both bulk and surface radiation damage effects, for the analysis of silicon detectors aimed at the High Luminosity LHC. In particular, a surface damage model has been developed by introducing the relevant parameters (NOX, NIT) extracted from experimental measurements carried out on p-type substrate test structures after gamma irradiations at doses in the range 10-500 Mrad(Si). An extended bulk model, by considering impact ionization and deep-level cross-sections variation, was included as well. The model has been validated through the comparison of the simulation findings with experimental measurements carried out at very high fluences (2×1016 1 MeV equivalent n/cm2) thus fostering the application of this TCAD approach for the design and optimization of the new generation of silicon detectors to be used in future HEP experiments.

  16. The effect of radiation damage on optical and scintillation properties of BGO crystals grown by the LTG Cz technique

    CERN Document Server

    Gusev, V A; Kupriyanov, I N; Kuznecov, G N; Shlegel, V N; Antsygin, V D; Vasiliev, Y V

    2002-01-01

    BGO crystals grown by the low-thermal-gradient Czochralski technique (LTG Cz) exhibit two distinct types of behavior upon radiation damage and recovery. The crystals termed as of L-type remain colorless after gamma-radiation doses as high as 10 Mrad. As the irradiation dose increases the scintillation light output shows a weak monotonous degradation to 15-25%, saturating at around several hundreds krad doses. The crystals termed as of N-type attain yellow coloration after irradiation. The light output drops abruptly for 35-50% as early as after 1 krad and does not change further on. The present work is devoted to the study of radiation damage effects, self-recovery, optically stimulated recovery and thermo-stimulated current in the L- and N-type BGO crystals produced by LTG Cz.

  17. Influence of the flux density on the radiation damage of bipolar silicon transistors by protons and electrons

    Energy Technology Data Exchange (ETDEWEB)

    Bannikov, Y.; Gorin, B.; Kozhevnikov, V.; Mikhnovich, V.; Gusev, L.

    1981-11-01

    It was found experimentally that the radiation damage of bipolar n-p-n transistors increased by a factor of 8--12 when the proton flux density was reduced from 4.07 x 10/sup 10/ to 2.5 x 10/sup 7/ cm/sup -2/ sec /sup -1/. In the case of p-n-p transistors the effect was opposite: there was a reduction in the radiation damage by a factor of 2--3 when the dose rate was lowered between the same limits. A similar effect was observed for electrons but at dose rates three orders of magnitude greater. The results were attributed to the dependences of the radiation defect-forming reactions on the charge state of defects which was influenced by the formation of disordered regions in the case of proton irradiation.

  18. X-ray-excited optical luminescence of protein crystals: a new tool for studying radiation damage during diffraction data collection.

    Science.gov (United States)

    Owen, Robin L; Yorke, Briony A; Pearson, Arwen R

    2012-05-01

    During X-ray irradiation protein crystals radiate energy in the form of small amounts of visible light. This is known as X-ray-excited optical luminescence (XEOL). The XEOL of several proteins and their constituent amino acids has been characterized using the microspectrophotometers at the Swiss Light Source and Diamond Light Source. XEOL arises primarily from aromatic amino acids, but the effects of local environment and quenching within a crystal mean that the XEOL spectrum of a crystal is not the simple sum of the spectra of its constituent parts. Upon repeated exposure to X-rays XEOL spectra decay non-uniformly, suggesting that XEOL is sensitive to site-specific radiation damage. However, rates of XEOL decay were found not to correlate to decays in diffracting power, making XEOL of limited use as a metric for radiation damage to protein crystals. © 2012 International Union of Crystallography

  19. Ion-beam cancer therapy: news about a multiscale approach to radiation damage.

    Science.gov (United States)

    Surdutovich, Eugene; Scifoni, Emanuele; Solov'yov, Andrey V

    2010-01-01

    We report the present stage of development of our multiscale approach to the physics related to radiation damage caused by irradiation of a tissue with energetic ions. This approach is designed to quantify the most important physical, chemical, and biological phenomena taking place during and following such an irradiation in order to understand the scenario of the events leading to cell death and provide a better means for clinically necessary calculations with an adequate accuracy. On this stage, we overview the latest progress in calculating energy spectra of secondary electrons in liquid water and the results of an application of the inelastic thermal spike model to liquid water in order to calculate the heat transfer in the vicinity of the incident-ion track. The dependence of energy distributions of secondary electrons, resulting from ionization of the liquid water, on the energy of primary ions is studied in two regimes. For slow ions, a new parameterization of energy spectra in liquid water is suggested. For fast ions, different dispersion schemes on the basis of a dielectric response function approach are used and compared. Thermal spike calculations indicate a very large temperature increase in the vicinity of ion tracks near the Bragg peak during the time interval from 10(-15) to 10(-9)s after the ion's passage. An increase of pressure, as large as tens of MPa, can also be induced during that time. These effects suggest a possibility of thermo-mechanical pathways to disruption of irradiated DNA. A combination of a temperature spike and electron/hole interactions may be a dominant pathway of DNA damage.

  20. Optical transmission radiation damage and recovery stimulation of DSB: Ce3+ inorganic scintillation material

    Science.gov (United States)

    Borisevich, A.; Dormenev, V.; Korjik, M.; Kozlov, D.; Mechinsky, V.; Novotny, R. W.

    2015-02-01

    Recently, a new scintillation material DSB: Ce3+ was announced. It can be produced in a form of glass or nano-structured glass ceramics with application of standard glass production technology with successive thermal annealing. When doped with Ce3+, material can be applied as scintillator. Light yield of scintillation is near 100 phe/MeV. Un-doped material has a wide optical window from 4.5eV and can be applied to detect Cherenkov light. Temperature dependence of the light yield LY(T) is 0.05% which is 40 times less than in case of PWO. It can be used for detectors tolerant to a temperature variation between -20° to +20°C. Several samples with dimensions of 15x15x7 mm3 have been tested for damage effects on the optical transmission under irradiation with γ-quanta. It was found that the induced absorption in the scintillation range depends on the doping concentration and varies in range of 0.5-7 m-1. Spontaneous recovery of induced absorption has fast initial component. Up to 25% of the damaged transmission is recuperated in 6 hours. Afterwards it remains practically constant if the samples are kept in the dark. However, induced absorption is reduced by a factor of 2 by annealing at 50°C and completely removed in a short time when annealing at 100°C. A significant acceleration of the induced absorption recovery is observed by illumination with visible and IR light. This effect is observed for the first time in a Ce-doped scintillation material. It indicates, that radiation induced absorption in DSB: Ce scintillation material can be retained at the acceptable level by stimulation with light in a strong irradiation environment of collider experiments.

  1. Resveratrol and its methoxy-derivatives as modulators of DNA damage induced by ionising radiation.

    Science.gov (United States)

    Traversi, Gianandrea; Fiore, Mario; Leone, Stefano; Basso, Emiliano; Di Muzio, Elena; Polticelli, Fabio; Degrassi, Francesca; Cozzi, Renata

    2016-07-01

    Various naturally occurring stilbene-like compounds that are related to resveratrol (RSV) possess some of the beneficial effects of the parent molecule and provide even further benefits. Therefore, a series of methoxylated analogues of RSV were prepared with the aim of increasing antitumour and proapoptotic activity. In a previous article, we studied two methoxy-derivatives, pterostilbene (PTERO) and trimethoxystilbene (TRIMETHOXY), in which the first was formed by the substitution of two hydroxyl groups with two methoxy groups (trans-3,5-dimethoxy-4'-hydroxystilbene) and the second was formed by the replacement of all three OH groups with methoxy groups (trans-3,5,4'-trimethoxystilbene). Both methoxy-derivatives showed stronger antioxidant activity when compared with RSV. In the present article, we focused on the analysis of the ability of RSV and its two methoxylated derivatives to protect proliferating non-tumoural cells from the damage induced by ionising radiation (IR). First we showed that the methoxy derivatives, contrary to their parental compound, are unable to affect topoisomerase enzyme and consequently are not clastogenic per se Second we showed that both PTERO and TRIMETHOXY more efficiently reduce the chromosome damage induced by IR. Furthermore, TRIMETHOXY, but not PTERO, causes a delay in cell proliferation, particularly in mitosis progression increasing the number of cells in metaphase at the expense of prophases and ana/telophases. © The Author 2016. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Low-temperature low-damage sterilization based on UV radiation through plasma immersion

    Science.gov (United States)

    Pollak, J.; Moisan, M.; Kéroack, D.; Boudam, M. K.

    2008-07-01

    This paper introduces a new type of high-frequency (HF) sustained discharge where the HF field applicator is a planar transmission line that allows us to fill with plasma a long chamber of rectangular cross-section (typically 1 m × 15 cm × 5 cm). Peculiar interesting features of this plasma source are a low gas temperature (typically below 40 °C in the 1 Torr range in argon), broadband impedance matching with no need for retuning, stability and reproducibility of the discharge (non-resonant behaviour). This type of plasma source could be useful for web processing; nonetheless, it is applied here to plasma sterilization, taking advantage of its low gas temperature to inactivate microorganisms on polymer-made medical devices to avoid damaging them. The predominant biocide species are the UV photons emitted by the discharge whereas most plasma sterilization techniques call for reactive species such as O atoms and OH molecules, which induce significant erosion damage on polymers. Polystyrene microspheres are actually observed to be erosion-free under the current plasma sterilization conditions (scanning electron micrographs have been examined). Moreover, inactivation is quite fast: 106 B. atrophaeus spores deposited on a Petri dish are inactivated in less than 1 min. Correlation of the UV radiation with the spore inactivation rate is examined by (i) considering the emitted light intensity integrated over the 112-180 nm vacuum UV (VUV) range with a photomultiplier; (ii) looking with an optical spectrometer at the emission spectrum over the 200-400 nm UV range; (iii) using absorption spectroscopy to determine the role of the VUV argon resonant lines (105 and 107 nm) on spore inactivation. It is found that the test-reference spores are mainly inactivated by VUV photons (112-180 nm) that are primarily emitted by impurities present in the argon plasma.

  3. Detection of some irradiated spices on the basis of radiation induced damage of starch

    Science.gov (United States)

    Farkas, J.; Sharif, M. M.; Koncz, Á.

    Untreated and irradiated samples of spices were suspended in water, alkalized, and after heat-gelatinization, the apparent viscosity was determined by a rotational viscometer. Several spices, i.e. white pepper, black pepper, nutmeg and ginger showed considerable loss of viscosity as a function of γ-radiation dose in the dose range required for microbial decontamination of natural spices. Less promising results were obtained with spices such as allspice, garlic powder, and onion powder forming low-viscosity heat-treated suspensions even when unirradiated viscometric studies were also performed with a number of pepper samples of various origin to estimate the "natural" variation of rheological properties. Irradiation and storage studies were performed with ground black pepper samples of moisture contents in equilibrium with air of 25%, 50% and 75% R.H., respectively, either untreated or irradiated with 4, 8, 16 or 32 kGy, to study the effect of equilibrium relative humidity and storage time on detectability of radiation treatment. During the entire storage period of 100 days, statistically significant differences of the apparent viscosities of heat-gelatinized suspensions remained detectable between untreated samples and those irradiated with 8 kGy or higher doses. The apparent viscosity of high-moisture (75% E.R.H.) untreated samples was decreasing during long-term storage. Differences between viscosities of untreated and irradiated samples were enlarged when measured at elevated temperatures such as 50°C in the rotational viscometer, or in the boiling-water bath of a falling number apparatus. Other analytical indices such as onset and peak temperatures of gelatinization endotherms by DSC (damaged starch content), by colorimetry, reducing sugar content, alcohol-induced turbidity of hot water extracts of pepper samples, have been changed less dramatically by irradiation than the apparent viscosity of the gelatinized suspensions

  4. Quantification of radiation-induced lung damage with CT scans - The possible benefit for radiogenomics

    Energy Technology Data Exchange (ETDEWEB)

    De Ruysscher, Dirk [Radiation Oncology, Univ. Hospitals Leuven/KU Leuven, Leuven (Belgium); Dept. of Radiation Oncology (Maastro clinic), Maastricht Univ. Medical Center, Maastricht (Netherlands)], e-mail: dirk.deruysscher@uzleuven.be; Sharifi, Hoda [Dept. of Radiation Oncology (Maastro clinic), Maastricht Univ. Medical Center, Maastricht (Netherlands); Defraene, Gilles [Radiation Oncology, Univ. Hospitals Leuven/KU Leuven, Leuven (Belgium)] [and others

    2013-10-15

    Background: Radiation-induced lung damage (RILD) is an important problem. Although physical parameters such as the mean lung dose are used in clinical practice, they are not suited for individualised radiotherapy. Objective, quantitative measurements of RILD on a continuous instead of on an ordinal, semi-quantitative, semi-subjective scale, are needed. Methods: Hounsfield unit (HU) changes before versus three months post-radiotherapy were correlated per voxel with the radiotherapy dose in 95 lung cancer patients. Deformable registration was used to register pre- and post-CT scans and the density increase was quantified for various dose bins. The dose-response curve for increased HU was quantified using the slope of a linear regression (HU/Gy). The end-point for the toxicity analysis was dyspnoea = grade 2. Results: Radiation dose was linearly correlated with the change in HU (mean R2 = 0.74 {+-} 0.28). No differences in HU/Gy between groups treated with stereotactic radiotherapy, conventional radiotherapy alone, sequential or concurrent chemo-radiotherapy were observed. In the whole patient group, 33/95 (34.7%) had dyspnoea {>=} G2. Of the 48 patients with a HU/Gy below the median, 16 (33.3%) developed dyspnoea = G2, while in the 47 patients with a HU/Gy above the median, 17 (36.1%) had dyspnoea {>=}G2 (not significant). Individual patients showed a nearly 21-fold difference in radiosensitivity, with HU/Gy ranging from 0 to 10 HU/Gy. Conclusions: HU changes identify objectively the whole range of individual radiosensitivity on a continuous, quantitative scale. CT density changes may allow more robust and accurate radiogenomics studies.

  5. LHCb Vertex Locator: Performance and radiation damage in LHC Run 1 and preparation for Run 2

    Science.gov (United States)

    Szumlak, T.; Obła˛kowska-Mucha, A.

    2016-07-01

    LHCb is a dedicated experiment to study New Physics in the decays of heavy hadrons at the Large Hadron Collider (LHC) at CERN. Heavy hadrons are identified through their flight distance in the Vertex Locator (VELO). The VELO comprises 42 modules made of two n+-on-n 300 μm thick half-disc silicon sensors with R- and Φ-measuring micro-strips. In order to allow retracting the detector, the VELO is installed as two movable halves containing 21 modules each. The detectors are operated in a secondary vacuum and are cooled by a bi-phase CO2 cooling system. During data taking in LHC Run 1 the LHCb VELO has operated with an extremely high efficiency and excellent performance. The track finding efficiency is typically greater than 98%. An impact parameter resolution of less than 35 μm is achieved for particles with transverse momentum greater than 1 GeV/c. An overview of all important performance parameters will be given. The VELO sensors have received a large and non-uniform radiation dose of up to 1.2 ×1014 1 MeV neutron equivalent cm-2 during the first LHC run. Silicon type-inversion has been observed in regions close to the interaction point. The preparations for LHC Run 2 are well under way and the VELO has already recorded tracks from injection line tests. The current status and plans for new operational procedures addressing the non-uniform radiation damage are shortly discussed.

  6. Investigation of new sensor concepts and development of an effective model for the simulation of radiation damage hochbestrahlter silicon particle detectors

    CERN Document Server

    Eber, Robert

    Silicon sensors in the Tracker of the CMS experiment at CERN will suffer from sever radiation damage after the upgrade of the LHC beyond 2023. A new sensor design is presented and a two-defect radiation damage model for the simulation is developed for the prediction of the performance of future silicon sensors.

  7. Constructive and critical approach of the radiation damage simulation; Approche constructive et critique de la simulation du dommage d'irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Becquart, Ch

    2002-11-15

    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.)

  8. Amifostine, a radioprotectant agent, protects rat brain tissue lipids against ionizing radiation induced damage: an FTIR microspectroscopic imaging study.

    Science.gov (United States)

    Cakmak, Gulgun; Miller, Lisa M; Zorlu, Faruk; Severcan, Feride

    2012-04-15

    Amifostine is the only approved radioprotective agent by FDA for reducing the damaging effects of radiation on healthy tissues. In this study, the protective effect of amifostine against the damaging effects of ionizing radiation on the white matter (WM) and grey matter (GM) regions of the rat brain were investigated at molecular level. Sprague-Dawley rats, which were administered amifostine or not, were whole-body irradiated at a single dose of 800 cGy, decapitated after 24 h and the brain tissues of these rats were analyzed using Fourier transform infrared microspectroscopy (FTIRM). The results revealed that the total lipid content and CH(2) groups of lipids decreased significantly and the carbonyl esters, olefinic=CH and CH(3) groups of lipids increased significantly in the WM and GM after exposure to ionizing radiation, which could be interpreted as a result of lipid peroxidation. These changes were more prominent in the WM of the brain. The administration of amifostine before ionizing radiation inhibited the radiation-induced lipid peroxidation in the brain. In addition, this study indicated that FTIRM provides a novel approach for monitoring ionizing radiation induced-lipid peroxidation and obtaining different molecular ratio images can be used as biomarkers to detect lipid peroxidation in biological systems. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Amifostine, a radioprotectant agent, protects rat brain tissue lipids against ionizing radiation induced damage: An FTIR microspectroscopic imaging study

    Energy Technology Data Exchange (ETDEWEB)

    Cakmak G.; Miller L.; Zorlu, F.; Severcan, F.

    2012-03-03

    Amifostine is the only approved radioprotective agent by FDA for reducing the damaging effects of radiation on healthy tissues. In this study, the protective effect of amifostine against the damaging effects of ionizing radiation on the white matter (WM) and grey matter (GM) regions of the rat brain were investigated at molecular level. Sprague-Dawley rats, which were administered amifostine or not, were whole-body irradiated at a single dose of 800 cGy, decapitated after 24 h and the brain tissues of these rats were analyzed using Fourier transform infrared microspectroscopy (FTIRM). The results revealed that the total lipid content and CH{sub 2} groups of lipids decreased significantly and the carbonyl esters, olefinic=CH and CH{sub 3} groups of lipids increased significantly in the WM and GM after exposure to ionizing radiation, which could be interpreted as a result of lipid peroxidation. These changes were more prominent in the WM of the brain. The administration of amifostine before ionizing radiation inhibited the radiation-induced lipid peroxidation in the brain. In addition, this study indicated that FTIRM provides a novel approach for monitoring ionizing radiation induced-lipid peroxidation and obtaining different molecular ratio images can be used as biomarkers to detect lipid peroxidation in biological systems.

  10. Radiation-induced lung damage promotes breast cancer lung-metastasis through CXCR4 signaling

    Science.gov (United States)

    Feys, Lynn; Descamps, Benedicte; Vanhove, Christian; Vral, Anne; Veldeman, Liv; Vermeulen, Stefan; De Wagter, Carlos; Bracke, Marc; De Wever, Olivier

    2015-01-01

    Radiotherapy is a mainstay in the postoperative treatment of breast cancer as it reduces the risks of local recurrence and mortality after both conservative surgery and mastectomy. Despite recent efforts to decrease irradiation volumes through accelerated partial irradiation techniques, late cardiac and pulmonary toxicity still occurs after breast irradiation. The importance of this pulmonary injury towards lung metastasis is unclear. Preirradiation of lung epithelial cells induces DNA damage, p53 activation and a secretome enriched in the chemokines SDF-1/CXCL12 and MIF. Irradiated lung epithelial cells stimulate adhesion, spreading, growth, and (transendothelial) migration of human MDA-MB-231 and murine 4T1 breast cancer cells. These metastasis-associated cellular activities were largely mimicked by recombinant CXCL12 and MIF. Moreover, an allosteric inhibitor of the CXCR4 receptor prevented the metastasis-associated cellular activities stimulated by the secretome of irradiated lung epithelial cells. Furthermore, partial (10%) irradiation of the right lung significantly stimulated breast cancer lung-specific metastasis in the syngeneic, orthotopic 4T1 breast cancer model. Our results warrant further investigation of the potential pro-metastatic effects of radiation and indicate the need to develop efficient drugs that will be successful in combination with radiotherapy to prevent therapy-induced spread of cancer cells. PMID:26396176

  11. Incident particle range dependence of radiation damage in a power bipolar junction transistor

    Science.gov (United States)

    Liu, Chao-Ming; Li, Xing-Ji; Geng, Hong-Bin; Rui, Er-Ming; Guo, Li-Xin; Yang, Jian-Qun

    2012-10-01

    The characteristic degradations in silicon NPN bipolar junction transistors (BJTs) of type 3DD155 are examined under the irradiations of 25-MeV carbon (C), 40-MeV silicon (Si), and 40-MeV chlorine (Cl) ions respectively. Different electrical parameters are measured in-situ during the exposure of heavy ions. The experimental data shows that the changes in the reciprocal of the gain variation (Δ(1/β)) of 3DD155 transistors irradiated respectively by 25-MeV C, 40-MeV Si, and 40-MeV Cl ions each present a nonlinear behaviour at a low fluence and a linear response at a high fluence. The Δ(1/β) of 3DD155 BJT irradiated by 25-MeV C ions is greatest at a given fluence, a little smaller when the device is irradiated by 40-MeV Si ions, and smallest in the case of the 40-MeV Cl ions irradiation. The measured and calculated results clearly show that the range of heavy ions in the base region of BJT affects the level of radiation damage.

  12. Incident particle range dependence of radiation damage in a power bipolar junction transistor

    Institute of Scientific and Technical Information of China (English)

    Liu Chao-Ming; Li Xing-Ji; Geng Hong-Bin; Rui Er-Ming; Guo Li-Xin; Yang Jian-Qun

    2012-01-01

    The characteristic degradations in silicon NPN bipolar junction transistors (BJTs) of type 3DD155 are examined under the irradiations of 25-MeV carbon (C),40-MeV silicon (Si),and 40-MeV chlorine (C1) ions respectively.Different electrical parameters are measured in-situ during the exposure of heavy ions.The experimental data shows that the changes in the reciprocal of the gain variation (△(1/β)) of 3DD155 transistors irradiated respectively by 25-MeV C,40-MeV Si,and 40-MeV C1 ions each present a nonlinear behaviour at a low fluence and a linear response at a high fluence.The △(1/β) of 3DDl55 BJT irradiated by 25-MeV C ions is greatest at a given fluence,a little smaller when the device is irradiated by 40-MeV Si ions,and smallest in the case of the 40-MeV C1 ions irradiation.The measured and calculated results clearly show that the range of heavy ions in the base region of BJT affects the level of radiation damage.

  13. Inter-atomic potentials for radiation damage studies in CePO4 monazite

    Science.gov (United States)

    Jolley, Kenny; Asuvathraman, Rajaram; Smith, Roger

    2017-02-01

    An original empirical potential used for modelling phosphate glasses is adapted to be suitable for use with monazite (CePO4) so as to have a consistent formulation for radiation damage studies of phosphates. This is done by adding a parameterisation for the Ce-O interaction to the existing potential set. The thermal and structural properties of the resulting computer model are compared to experimental results. The parameter set gives a stable monazite structure where the volume of the unit cell is almost identical to that measured experimentally, but with some shrinkage in the a and b lengths and a small expansion in the c direction compared to experiment. The thermal expansion, specific heat capacity and estimates of the melting point are also determined. The estimate of the melting temperature of 2500 K is comparable to the experimental value of 2318 ± 20 K, but the simulated thermal expansion of 49 ×10-6 K-1 is larger than the usually reported value. The simulated specific heat capacity at constant pressure was found to be approximately constant at 657 J kg-1 K-1 in the range 300-1000 K, however, this is not observed experimentally or in more detailed ab initio calculations.

  14. An edge-TCT setup for the investigation of radiation damaged silicon sensors

    Energy Technology Data Exchange (ETDEWEB)

    Feindt, Finn; Scharf, Christian; Garutti, Erika; Klanner, Robert [Institute for Experimental Physics, Hamburg University, Luruper Chaussee 149, D-22761 Hamburg (Germany)

    2016-07-01

    The aim of this work is to measure the electric field, drift velocity and charge collection of electrons and holes in radiation-damaged silicon strip sensors. For this purpose the edge Transient Current Technique (TCT) is employed. In contrast to conventional TCT, this method requires light from a sub-ns pulsed, infrared laser to be focused to a μm-size spot and scanned across the polished edge of a strip sensor. Thus electron-hole pairs are generated at a known depth in the sensor. Electrons and holes drift in the electric field and induce transient currents on the sensor electrodes. The current wave forms are analyzed as a function of the applied voltage and the position of the laser focus in order to determine the electric field, the drift velocities and the charge collection. In this talk the setup and the procedure for polishing the sensor edge are described, and first results, regarding the measurement of the laser light focus are presented.

  15. Effects of atomic grain boundary structures on primary radiation damage in α-Fe

    Energy Technology Data Exchange (ETDEWEB)

    Esfandiarpour, A. [Department of Physics, Payame Noor University (PNU), P.O. BOX 19395-3697, Tehran (Iran, Islamic Republic of); Feghhi, S.A.H., E-mail: a.feghhi@gmail.com [Department of Radiation Application, Shahid Beheshti University G.C., Tehran (Iran, Islamic Republic of); Shokri, A.A. [Department of Physics, Payame Noor University (PNU), P.O. BOX 19395-3697, Tehran (Iran, Islamic Republic of)

    2015-11-01

    In this paper, we used five different grain boundary (GB) structures including two twists, two symmetric tilts and one asymmetric tilt for α-Fe, in order to study the influence of different GB structures on the production and time evolution of defects. Energetic behavior of point defects near GBs is investigated and analyzed using Molecular Static (MS) method to calculate and compare the “defect absorbency” of each structure. The primary radiation damage state near each GB structure is simulated using Molecular Dynamic (MD) method for 3 keV and 6 keV primary-knocked on atom (PKA) with velocity vector perpendicular to the GB plane at various distances in 300 K. We found that all five GB structures can decrease the defect number in bulk region, if cascade center locates on the GB plane (prefect overlap) and increase the vacancy number, if the overlap is imperfect. This depends on the energy of PKA and its distance from GB plane. Also, the results proved that the magnitude of the observed variations depends on the atomic structure of GB. Furthermore, the GBs that have stronger “interstitial absorbency” produce an excess concentration of vacancies in the bulk region, while the edge of the cascades overlaps with GB plane. This is the result of bigger “interstitial absorbency” of GBs in comparison with vacancies.

  16. Effects of 900-MHz microwave radiation on gamma-ray-induced damage to mouse hematopoietic system.

    Science.gov (United States)

    Cao, Yi; Xu, Qian; Jin, Zong-Da; Zhang, Jun; Lu, Min-Xia; Nie, Ji-Hua; Tong, Jian

    2010-01-01

    Exposure of humans simultaneously to microwave and gamma-ray irradiation may be a commonly encountered phenomenon. In a previous study data showed that low-dose microwave radiation increased the survival rate of mice irradiated with 8Gy gamma-ray; however, the mechanisms underlying these findings remain unclear. Consequently, studies were undertaken to examine the effects of microwave exposure on hematopoietic system adversely altered by gamma-ray irradiation in mice. Preexposure to low-dose microwaves attenuated the damage produced by gamma-ray irradiation as evidenced by less severe pathological alterations in bone marrow and spleen. The protective effects of microwaves were postulated to be due to up-expression of some hematopoietic growth factors, stimulation of proliferation of the granulocyte-macrophages in bone marrow, and inhibition of the gamma-ray induced suppression of hematopoietic stem cells/hematopoietic progenitor cells. Data thus indicate that prior exposure to microwaves may be beneficial in providing protection against injuries produced by gamma-ray on the hematopoietic system in mice.

  17. Cross-generational trans fat intake exacerbates UV radiation-induced damage in rat skin.

    Science.gov (United States)

    Barcelos, R C S; Vey, L T; Segat, H J; Roversi, K; Roversi, Kr; Dias, V T; Trevizol, F; Kuhn, F T; Dolci, G S; Pase, C S; Piccolo, J; Veit, J C; Emanuelli, T; Luz, S C A; Bürger, M E

    2014-07-01

    We evaluated the influence of dietary fats on ultraviolet radiation (UVR)-induced oxidative damage in skin of rats. Animals from two consecutive generations born of dams supplemented with fats during pregnancy and breastfeeding were maintained in the same supplementation: soybean-oil (SO, rich in n-6 FA, control group), fish-oil (FO, rich in n-3 FA) or hydrogenated-vegetable-fat (HVF, rich in TFA). At 90 days of age, half the animals from the 2nd generation were exposed to UVR (0.25 J/cm(2)) 3×/week for 12 weeks. The FO group presented higher incorporation of n-3 FA in dorsal skin, while the HVF group incorporated TFA. Biochemical changes per se were observed in skin of the HVF group: greater generation of reactive oxygen species (ROS), lower mitochondrial integrity and increased Na(+)K(+)-ATPase activity. UVR exposure increased skin wrinkles scores and ROS generation and decreased mitochondrial integrity and reduced-glutathione levels in the HVF group. In FO, UVR exposure was associated with smaller skin thickness and reduced levels of protein-carbonyl, together with increased catalase activity and preserved Na(+)K(+)-ATPase function. In conclusion, while FO may be protective, trans fat may be harmful to skin health by making it more vulnerable to UVR injury and thus more prone to develop photoaging and skin cancer.

  18. Structural and Optical Investigations of Radiation Damage in Transparent PET Polymer Films

    Directory of Open Access Journals (Sweden)

    Shiv Govind Prasad

    2011-01-01

    Full Text Available Effects of gamma irradiation at different doses up to 135 kGy on polyethylene terephthalate (PET polymer films have been investigated by X-ray diffraction (XRD, Fourier transform infrared (FTIR spectroscopy, and ultraviolet-visible (UV-VIS spectroscopy. From XRD analysis, it was found that even at a high dose of gamma irradiation of 135 kGy, crystallinity of the PET samples remain unchanged. However, the FTIR peak at 871 cm−1 (depicting C–H bending mode of out-of-plane vibration and another at 1303 cm−1 (representing C–H bending mode of in-plane vibration disappear for gamma-irradiated PET. In this study, it has also been found that γ-irradiation in air enhances the optical absorption in the wavelength region 320–370 nm. This has been attributed to free radicals being produced in the polymer by the γ-radiation. Further, the free radicals react with oxygen of air to form carbonyl group and hydroxyls. With increasing γ-dose, there is a red shift of the UV—near visible cutoff for PET. XRD and FTIR observations on γ-damage have been correlated.

  19. Prognosis of surgically treated radiation-induced damage to the intestine

    Energy Technology Data Exchange (ETDEWEB)

    Jahnson, S.; Westerborn, O. (Orebro Medical Center Hospital, Orebro (Sweden)); Gerdin, B. (Akademiska Sjukhuset, Uppsala (Sweden))

    1992-10-01

    A series of 88 patients operated on during 24 years for radiation-induced damage (RID) to the intestinal tract were retrospectively reviewed and clinical and surgical factors were related to the ultimate prognosis by multivariate analysis. The first operation was performed on the small intestine in 47 patients, the large intestine in 32 patients or both in nine patients. Postoperative complications occurred in 35 patients (40%), with fatal outcome in 12 (13%). Thirty-one patients (35%) required further surgery and altogether 19 patients (22%) ultimately died from RID. Negative prognostic factors after the first operation were post-operative intestinal leak (P < 0.05) and operation for fistula or perforation (P < 0.01). The outcome after the last operation was negatively influenced by intestinal leak (P < 0.001) by the choice of bypass as operative procedure (P < 0.01) and by operation for fistula or perforation (P < 0.01). In addition, 43% of the patients in whom the disease had progressed between two explorations died from RID. Thus, the severity of the RID as diagnosed at laparotomy, and progression of the disease between two subsequent explorations were related to the prognosis. Care should be taken to avoid intestinal leak. Resections should be preferred to bypass of injured intestine whenever possible. (author).

  20. Formation of DNA strand breaks in peripheral lymphocytes of rats after exposure to natural sunlight.

    Science.gov (United States)

    Rodrigues-Junior, Dorival Mendes; Melo, Ana Amélia de Carvalho; da Silva, Benedito Borges; Lopes-Costa, Pedro Vitor

    2012-04-01

    This paper aims to evaluate the genotoxicity in peripheral blood lymphocytes of rats after exposure to sunlight at different time points of day in a tropical region of Brazil (5 degrees S, 42 degrees W). Thirty Wistar-Hannover rats, three months old, were randomly divided into three groups of 10 animals each: Group I [control, without exposure to ultraviolet (UV) radiation], Group II (exposed to sunlight during 08:00 a.m. to 10:00 a.m.), and Group III (exposed to sunlight during 10:00 a.m. to 12:00 a.m.). After a week of exposure, peripheral blood samples were taken from the tail of these animals to prepare smears on two slides per animal. In 24 h after exposure to sunlight in Group III, a new collection was obtained to observe the repair activity. The alkaline comet assay was used in this study to evaluate the genotoxic activity of sunlight (P exposure to sunlight in Group III showed genotoxic action in comparison to the other groups (P sunlight (UVA-B) in lymphocytes of mammals from 10:00 a.m. to 12:00 a.m., due to a higher intensity of UV in this tropical region.