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Sample records for astrophysical ionizing radiation

  1. Solar irradiance changes and photobiological effects at Earth's surface following astrophysical ionizing radiation events

    CERN Document Server

    Thomas, Brian C; Snyder, Brock R

    2015-01-01

    Astrophysical ionizing radiation events have been recognized as a potential threat to life on Earth, primarily through depletion of stratospheric ozone and subsequent increase in surface-level solar ultraviolet radiation. Simulations of the atmospheric effects of a variety of events (such as supernovae, gamma-ray bursts, and solar proton events) have been previously published, along with estimates of biological damage at Earth's surface. In this work, we employed the TUV radiative transfer model to expand and improve calculations of surface-level irradiance and biological impacts following an ionizing radiation event. We considered changes in surface-level UVB, UVA, and photosynthetically active radiation (visible light) for clear-sky conditions and fixed aerosol parameter values. We also considered a wide range of biological effects on organisms ranging from humans to phytoplankton. We found that past work overestimated UVB irradiance, but that relative estimates for increase in exposure to DNA damaging radi...

  2. Solar Irradiance Changes And Photobiological Effects At Earth's Surface Following Astrophysical Ionizing Radiation Events

    Science.gov (United States)

    Thomas, Brian; Neale, Patrick

    2016-01-01

    Astrophysical ionizing radiation events have been recognized as a potential threat to life on Earth for decades. Although there is some direct biological damage on the surface from redistributed radiation several studies have indicated that the greatest long term threat is from ozone depletion and subsequent heightened solar ultraviolet (UV) radiation. It is known that organisms exposed to this irradiation experience harmful effects such as sunburn and even direct damage to DNA, proteins, or other cellular structures. Simulations of the atmospheric effects of a variety of events (such as supernovae, gamma-ray bursts, and solar proton events) have been previously published, along with estimates of biological damage at Earth's surface. In the present work, we employed a radiative transfer model to expand and improve calculations of surface-level irradiance and biological impacts following an ionizing radiation event. We considered changes in surface-level UVB, UVA, and photosynthetically active radiation (visible light). Using biological weighting functions we have considered a wide range of effects, including: erythema and skin cancer in humans; inhibition of photosynthesis in the diatom Phaeodactylum sp. and dinoflagellate Prorocentrum micans inhibition of carbon fixation in Antarctic phytoplankton; inhibition of growth of oat (Avena sativa L. cv. Otana) seedlings; and cataracts. We found that past work overestimated UVB irradiance, but that relative estimates for increase in exposure to DNA damaging radiation are still similar to our improved calculations. We also found that the intensity of biologically damaging radiation varies widely with organism and specific impact considered; these results have implications for biosphere-level damage following astrophysical ionizing radiation events. When considering changes in surface-level visible light irradiance, we found that, contrary to previous assumptions, a decrease in irradiance is only present for a short time in

  3. Solar irradiance changes and photobiological effects at earth's surface following astrophysical ionizing radiation events.

    Science.gov (United States)

    Thomas, Brian C; Neale, Patrick J; Snyder, Brock R

    2015-03-01

    Astrophysical ionizing radiation events have been recognized as a potential threat to life on Earth, primarily through depletion of stratospheric ozone and subsequent increase in surface-level solar ultraviolet radiation. Simulations of the atmospheric effects of a variety of events (such as supernovae, gamma-ray bursts, and solar proton events) have been previously published, along with estimates of biological damage at Earth's surface. In this work, we employed the Tropospheric Ultraviolet and Visible (TUV) radiative transfer model to expand and improve calculations of surface-level irradiance and biological impacts following an ionizing radiation event. We considered changes in surface-level UVB, UVA, and photosynthetically active radiation (visible light) for clear-sky conditions and fixed aerosol parameter values. We also considered a wide range of biological effects on organisms ranging from humans to phytoplankton. We found that past work overestimated UVB irradiance but that relative estimates for increase in exposure to DNA-damaging radiation are still similar to our improved calculations. We also found that the intensity of biologically damaging radiation varies widely with organism and specific impact considered; these results have implications for biosphere-level damage following astrophysical ionizing radiation events. When considering changes in surface-level visible light irradiance, we found that, contrary to previous assumptions, a decrease in irradiance is only present for a short time in very limited geographical areas; instead we found a net increase for most of the modeled time-space region. This result has implications for proposed climate changes associated with ionizing radiation events.

  4. Solar irradiance changes and phytoplankton productivity in Earth's ocean following astrophysical ionizing radiation events

    CERN Document Server

    Neale, Patrick J

    2016-01-01

    Two atmospheric responses to simulated astrophysical ionizing radiation events significant to life on Earth are production of odd-nitrogen species, especially NO2, and subsequent depletion of stratospheric ozone. Ozone depletion increases incident short-wavelength ultraviolet radiation (UVB, 280-315 nm) and longer ( > 600 nm) wavelengths of photosynthetically available radiation (PAR, 400 -700 nm). On the other hand, the NO2 haze decreases atmospheric transmission in the long-wavelength UVA (315-400 nm) and short wavelength PAR. Here we use the results of previous simulations of incident spectral irradiance following an ionizing radiation event to predict changes in Terran productivity focusing on photosynthesis of marine phytoplankton. The prediction is based on a spectral model of photosynthetic response developed for the dominant genera in central regions of the ocean (Synechococcus and Prochlorococcus), and remote-sensing based observations of spectral water transparency, temperature, wind speed and mixed...

  5. Amphibian nitrate stress as an additional terrestrial threat from astrophysical ionizing radiation events?

    CERN Document Server

    Thomas, Brian C

    2008-01-01

    As diversity in amphibian species declines, the search for causes has intensified. Work in this area has shown that amphibians are especially susceptible to the combination of heightened UVB radiation and increased nitrate concentrations. Various astrophysical events have been suggested as sources of ionizing radiation that could pose a threat to life on Earth, through destruction of the ozone layer and subsequent increase in UVB, followed by deposition of nitrate. In this study, we investigate whether the nitrate deposition following an ionizing event is sufficiently large to cause an additional stress beyond that of the heightened UVB previously considered. We have converted predicted nitrate depositions to concentration values, utilizing data from the New York State Department of Environmental Conservation Acid Rain Monitoring Network web site. Our results show that the increase in nitrate concentration in bodies of water following the most intense ionization event likely in the last billion years would no...

  6. Ground-level ozone following astrophysical ionizing radiation events: an additional biological hazard?

    CERN Document Server

    Thomas, Brian C

    2015-01-01

    Astrophysical ionizing radiation events such as supernovae, gamma-ray bursts, and solar proton events have been recognized as a potential threat to life on Earth, primarily through depletion of stratospheric ozone and subsequent increase in solar UV radiation at Earth's surface and in the upper levels of the ocean. Other work has also considered the potential impact of nitric acid rainout, concluding that no significant threat is likely. Not yet studied to-date is the potential impact of ozone produced in the lower atmosphere following an ionizing radiation event. Ozone is a known irritant to organisms on land and in water and therefore may be a significant additional hazard. Using previously completed atmospheric chemistry modeling we have examined the amount of ozone produced in the lower atmosphere for the case of a gamma-ray burst and find that the values are too small to pose a significant additional threat to the biosphere. These results may be extended to other ionizing radiation events, including supe...

  7. Solar Irradiance Changes and Phytoplankton Productivity in Earth's Ocean Following Astrophysical Ionizing Radiation Events.

    Science.gov (United States)

    Neale, Patrick J; Thomas, Brian C

    2016-04-01

    Two atmospheric responses to simulated astrophysical ionizing radiation events significant to life on Earth are production of odd-nitrogen species, especially NO2, and subsequent depletion of stratospheric ozone. Ozone depletion increases incident short-wavelength ultraviolet radiation (UVB, 280-315 nm) and longer (>600 nm) wavelengths of photosynthetically available radiation (PAR, 400-700 nm). On the other hand, the NO2 haze decreases atmospheric transmission in the long-wavelength UVA (315-400 nm) and short-wavelength PAR. Here, we use the results of previous simulations of incident spectral irradiance following an ionizing radiation event to predict changes in terran productivity focusing on photosynthesis of marine phytoplankton. The prediction is based on a spectral model of photosynthetic response, which was developed for the dominant genera in central regions of the ocean (Synechococcus and Prochlorococcus), and on remote-sensing-based observations of spectral water transparency, temperature, wind speed, and mixed layer depth. Predicted productivity declined after a simulated ionizing event, but the effect integrated over the water column was small. For integrations taking into account the full depth range of PAR transmission (down to 0.1% of utilizable PAR), the decrease was at most 2-3% (depending on strain), with larger effects (5-7%) for integrations just to the depth of the surface mixed layer. The deeper integrations were most affected by the decreased utilizable PAR at depth due to the NO2 haze, whereas shallower integrations were most affected by the increased surface UV. Several factors tended to dampen the magnitude of productivity responses relative to increases in surface-damaging radiation, for example, most inhibition in the modeled strains is caused by UVA and PAR, and the greatest relative increase in damaging exposure is predicted to occur in the winter when UV and productivity are low.

  8. Nitric Acid Deposition following an Astrophysical Ionizing Radiation Event is below Critical Loads for Terrestrial and Freshwater Ecosystems

    CERN Document Server

    Melott, Ben Neuenswander Adrian

    2014-01-01

    Nitric acid rainout is one of the effects of an astrophysical ionizing radiation event. The predicted values of nitrate rainout from previous work for a typical gamma ray burst (GRB) within our galaxy serve as an extreme example and are shown to be below critical loads of eutrophication and acidification for ecoregions in Europe and the US.

  9. 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...

  10. Astrophysical Ionizing Radiation and the Earth: A Brief Review and Census of Intermittent Intense Sources

    CERN Document Server

    Melott, Adrian L

    2011-01-01

    Cosmic radiation backgrounds are a constraint on life, and their distribution will affect the Galactic Habitable Zone. Life on Earth has developed in the context of these backgrounds, and characterizing event rates will elaborate the important influences. This in turn can be a base for comparison with other potential life-bearing planets. In this review we estimate the intensities and rates of occurrence of many kinds of strong radiation bursts by astrophysical entities ranging from gamma-ray bursts at cosmological distances to the Sun itself. Many of these present potential hazards to the biosphere: on timescales long compared with human history, the probability of an event intense enough to disrupt life on the land surface or in the oceans becomes large. We enumerate the known sources of radiation and characterize their intensities at the Earth and rates or upper limits on these quantities. When possible, we estimate a "lethal interval", our best estimate of how often a major extinction-level event is proba...

  11. Ionization Modeling Astrophysical Gaseous Structures. I. The Optically Thin Regime

    CERN Document Server

    Churchill, Christopher W; Medina, Amber; Vliet, Jacob R Vander

    2014-01-01

    We present a code for modelling the ionization conditions of optically thin astrophysical gas structures. Given the gas hydrogen density, equilibrium temperature, elemental abundances, and the ionizing spectrum, the code solves the equilibrium ionization fractions and number densities for all ions from hydrogen to zinc. The included processes are photoionization, Auger ionization, direct collisional ionization, excitation auto-ionization, charge exchange ionization, two-body radiative recombination, dielectronic recombination, and charge exchange recombination. The ionizing spectrum can be generalized to include the ultraviolet background (UVB) and/or Starburst99 stellar populations of various masses, ages, metallicities, and distances. The ultimate goal with the code is to provide fast computation of the ionization conditions of gas in N-body + hydrodynamics cosmological simulations, in particular adaptive mesh refinement codes, in order to facilitate absorption line analysis of the simulated gas for compari...

  12. Experimental radiative lifetimes for highly excited states and calculated oscillator strengths for lines of astrophysical interest in singly ionized cobalt (Co II)

    Science.gov (United States)

    Quinet, P.; Fivet, V.; Palmeri, P.; Engström, L.; Hartman, H.; Lundberg, H.; Nilsson, H.

    2016-11-01

    This work reports new experimental radiative lifetimes and calculated oscillator strengths for transitions of astrophysical interest in singly ionized cobalt. More precisely, 19 radiative lifetimes in Co+ have been measured with the time-resolved laser-induced fluorescence technique using one- and two-step excitations. Out of these, seven belonging to the high lying 3d7(4F)4d configuration in the energy range 90 697-93 738 cm-1 are new, and the other 12 from the 3d7(4F)4p configuration with energies between 45 972 and 49 328 cm-1 are compared with previous measurements. In addition, a relativistic Hartree-Fock model including core-polarization effects has been employed to compute transition rates. Supported by the good agreement between theory and experiment for the lifetimes, new reliable transition probabilities and oscillator strengths have been deduced for 5080 Co II transitions in the spectral range 114-8744 nm.

  13. Radiative Magnetic Reconnection in Astrophysics

    CERN Document Server

    Uzdensky, Dmitri A

    2015-01-01

    I review a new rapidly growing area of high-energy plasma astrophysics --- radiative magnetic reconnection, i.e., a reconnection regime where radiation reaction influences reconnection dynamics, energetics, and nonthermal particle acceleration. This influence be may be manifested via a number of astrophysically important radiative effects, such as radiation-reaction limits on particle acceleration, radiative cooling, radiative resistivity, braking of reconnection outflows by radiation drag, radiation pressure, viscosity, and even pair creation at highest energy densities. Self-consistent inclusion of these effects in magnetic reconnection theory and modeling calls for serious modifications to our overall theoretical approach to the problem. In addition, prompt reconnection-powered radiation often represents our only observational diagnostic tool for studying remote astrophysical systems; this underscores the importance of developing predictive modeling capabilities to connect the underlying physical condition...

  14. Experimental radiative lifetimes for highly excited states and calculated oscillator strengths for lines of astrophysical interest in singly ionized cobalt (Co II)

    CERN Document Server

    Quinet, P; Palmeri, P; Engstrom, L; Hartman, H; Lundberg, H; Nilsson, H

    2016-01-01

    This work reports new experimental radiative lifetimes and calculated oscillator strengths for transitions of astrophysical interest in singly ionized cobalt. More pre- cisely, nineteen radiative lifetimes in Co+ have been measured with the time-resolved laser-induced fluorescence technique using one- and two-step excitations. Out of these, seven belonging to the high lying 3d$^7$($^4$F)4d configuration in the energy range 90697 - 93738 cm$^{-1}$ are new, and the other twelve from th3d$^7$($^4$F)F)4p configuration with energies between 45972 and 49328 cm$^{-1}$1 are compared with previous measurements. In addition, a relativistic Hartree-Fock model including core-polarization e?ects has been employed to compute transition rates. Supported by the good agreement between theory and experiment for the lifetimes, new reliable transition probabilities and os- cillator strengths have been deduced for 5080 Co II transitions in the spectral range 114 - 8744 nm.

  15. Grackle: Chemistry and radiative cooling library for astrophysical simulations

    Science.gov (United States)

    Smith, Britton D.; Bryan, Greg L.; Glover, Simon C. O.; Goldbaum, Nathan J.; Turk, Matthew J.; Regan, John; Wise, John H.; Schive, Hsi-Yu; Abel, Tom; Emerick, Andrew; O'Shea, Brian W.; Anninos, Peter; Hummels, Cameron B.; Khochfar, Sadegh

    2016-12-01

    The chemistry and radiative cooling library Grackle provides options for primordial chemistry and cooling, photo-heating and photo-ionization from UV backgrounds, and support for user-provided arrays of volumetric and specific heating rates for astrophysical simulations and models. The library provides functions to update chemistry species; solve radiative cooling and update internal energy; and calculate cooling time, temperature, pressure, and ratio of specific heats (gamma), and has interfaces for C, C++, Fortran, and Python codes.

  16. Applications of ionizing radiations

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2014-07-01

    Developments in standard applications and brand new nuclear technologies, with high impact on the future of the agriculture, medicine, industry and the environmental preservation. The Radiation Technology Center (CTR) mission is to apply the radiation and radioisotope technologies in Industry, Health, Agriculture, and Environmental Protection, expanding the scientific knowledge, improving human power resources, transferring technology, generating products and offering services for the Brazilian society. The CTR main R and D activities are in consonance with the IPEN Director Plan (2011-2013) and the Applications of Ionizing Radiation Program, with four subprograms: Irradiation of Food and Agricultural Products; Radiation and Radioisotopes Applications in Industry and Environment; Radioactive Sources and Radiation Applications in Human Health; and Radioactive Facilities and Equipment for the Applications of Nuclear Techniques.

  17. The Iron Project:. Radiative Atomic Processes in Astrophysics

    Science.gov (United States)

    Nahar, Sultana N.

    2011-06-01

    Astronomical objects, such as, stars, galaxies, blackhole environments, etc are studied through their spectra produced by various atomic processes in their plasmas. The positions, shifts, and strengths of the spectral lines provide information on physical processes with elements in all ionization states, and various diagnostics for temperature, density, distance, etc of these objects. With presence of a radiative source, such as a star, the astrophysical plasma is dominated by radiative atomic processes such as photoionization, electron-ion recombination, bound-bound transitions or photo-excitations and de-excitations. The relevant atomic parameters, such as photoionization cross sections, electron-ion recombination rate coefficients, oscillator strengths, radiative transition rates, rates for dielectronic satellite lines etc are needed to be highly accurate for precise diagnostics of physical conditions as well as accurate modeling, such as, for opacities of astrophysical plasmas. for opacities of astrophysical plasmas. This report illustrates detailed features of radiative atomic processes obtained from accurate ab initio methods of the latest developments in theoretical quantum mechanical calculations, especially under the international collaborations known as the Iron Project (IP) and the Opacity Project (OP). These projects aim in accurate study of radiative and collsional atomic processes of all astrophysically abundant atoms and ions, from hydrogen to nickel, and calculate stellar opacities and have resulted in a large number of atomic parameters for photoionization and radiative transition probabilities. The unified method, which is an extension of the OP and the IP, is a self-consistent treatment for the total electron-ion recombination and photoionization. It incorporates both the radiative and the dielectronic recombination processes and provides total recombination rates and level-specific recombination rates for hundreds of levels for a wide range of

  18. Numerical Methods for Radiation Magnetohydrodynamics in Astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Klein, R I; Stone, J M

    2007-11-20

    We describe numerical methods for solving the equations of radiation magnetohydrodynamics (MHD) for astrophysical fluid flow. Such methods are essential for the investigation of the time-dependent and multidimensional dynamics of a variety of astrophysical systems, although our particular interest is motivated by problems in star formation. Over the past few years, the authors have been members of two parallel code development efforts, and this review reflects that organization. In particular, we discuss numerical methods for MHD as implemented in the Athena code, and numerical methods for radiation hydrodynamics as implemented in the Orion code. We discuss the challenges introduced by the use of adaptive mesh refinement in both codes, as well as the most promising directions for future developments.

  19. The dosimetry of ionizing radiation

    CERN Document Server

    1990-01-01

    A continuation of the treatise The Dosimetry of Ionizing Radiation, Volume III builds upon the foundations of Volumes I and II and the tradition of the preceeding treatise Radiation Dosimetry. Volume III contains three comprehensive chapters on the applications of radiation dosimetry in particular research and medical settings, a chapter on unique and useful detectors, and two chapters on Monte Carlo techniques and their applications.

  20. Maser Radiation in an Astrophysical Context (Overview)

    CERN Document Server

    Gentry, Eric S

    2013-01-01

    In this paper we will look at the phenomenon of Microwave Amplification by Stimulated Emission of Radiation (a maser system). We begin by deriving amplification by stimulated emission using time-dependent perturbation theory, in which the perturbation provided by external radiation. When this perturbation is applied to an ensemble of particles exhibiting a population inversion, the result is stimulated microwave radiation. We will explore both unsaturated and saturated masers and compare their properties. By understanding their gain, as well as the effect of line broadening, astronomers are to identify astrophysical masers. By studying such masers, we gain new insight into poorly understood physical environments, particularly those around young and old stars, and compact stellar bodies.

  1. Biological effects of ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Blaylock, B.G. [SENES Oak Ridge Inc., Oak Ridge, TN (United States); Theodorakis, C.W.; Shugart, L.R. [Oak Ridge National Lab., Oak Ridge, TN (United States). Environmental Sciences Division

    1996-12-31

    Natural populations have always been exposed to background levels of ionizing radiation; however, with the event of the nuclear age, studies about the effects of higher-than-background levels of ionizing radiation on individuals or populations of organisms became important. Originally, concern was focused on survival after large, acute radiation doses, and numerous studies document the somatic and genetic effects of acute ionizing radiation. However, there is a growing realization that chronic long-term exposure to higher-than-background levels of environmental radiation is more likely than is large acute exposure. Less than 10% of the literature on ionizing radiation effects deals with chronic long-term effects, and very few studies involve natural populations. In 1977, mosquito fish, Gambusia affinis, were experimentally introduced into a 0,45 ha, decommissioned, radioactive waste pond where the measured dose at the sediment-water interface was 1,150 rad/year. One year later, the fecundity of the population had not changed significantly. Eighteen years later, studies of the fish showed an inverse correlation between DNA strand breakage and fecundity in the contaminated pond. More recent studies have provided evidence that genetic diversity of the fish has increased in the contaminated site. These fish also have a greater prevalence of certain DNA banding patterns. Individuals displaying these banding patterns have a higher fecundity and lower degree of DNA strand breakage than individuals with less common banding patterns. Gambusia affinis has apparently adapted to the high background radiation, successfully surviving for approximately 50 generations. 31 refs, 5 figs.

  2. Radiative feedback from ionized gas

    CERN Document Server

    Glover, S C O

    2007-01-01

    H2 formation in metal-free gas occurs via the intermediate H- or H2+ ions. Destruction of these ions by photodissociation therefore serves to suppress H2 formation. In this paper, I highlight the fact that several processes that occur in ionized primordial gas produce photons energetic enough to photodissociate H- or H2+ and outline how to compute the photodissociation rates produced by a particular distribution of ionized gas. I also show that there are circumstances of interest, such as during the growth of HII regions around the first stars, in which this previously overlooked form of radiative feedback is of considerable importance.

  3. 29 CFR 1926.53 - Ionizing radiation.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Ionizing radiation. 1926.53 Section 1926.53 Labor... § 1926.53 Ionizing radiation. (a) In construction and related activities involving the use of sources of ionizing radiation, the pertinent provisions of the Nuclear Regulatory Commission's Standards...

  4. Intermittent Astrophysical Radiation Sources and Terrestrial Life

    Science.gov (United States)

    Melott, Adrian

    2013-04-01

    Terrestrial life is exposed to a variety of radiation sources. Astrophysical observations suggest that strong excursions in cosmic ray flux and spectral hardness are expected. Gamma-ray bursts and supernovae are expected to irradiate the atmosphere with keV to GeV photons at irregular intervals. Supernovae will produce large cosmic ray excursions, with time development varying with distance from the event. Large fluxes of keV to MeV protons from the Sun pose a strong threat to electromagnetic technology. The terrestrial record shows cosmogenic isotope excursions which are consistent with major solar proton events, and there are observations of G-stars suggesting that the rate of such events may be much higher than previously assumed. In addition there are unknown and unexplained astronomical transients which may indicate new classes of events. The Sun, supernovae, and gamma-ray bursts are all capable of producing lethal fluences, and some are expected on intervals of 10^8 years or so. The history of life on Earth is filled with mass extinctions at a variety of levels of intensity. Most are not understood. Astrophysical radiation may play a role, particularly from large increases in muon irradiation on the ground, and changes in atmospheric chemistry which deplete ozone, admitting increased solar UVB. UVB is strongly absorbed by DNA and proteins, and breaks the chemical bonds---it is a known carcinogen. High muon fluxes will also be damaging to such molecules, but experiments are needed to pin down the rate. Solar proton events which are not directly dangerous for the biota may nevertheless pose a major threat to modern electromagnetic technology through direct impact on satellites and magnetic induction of large currents in power grids, disabling transformers. We will look at the kind of events that are expected on timescales from human to geological, and their likely consequences.

  5. Amplification of OAM Radiation by Astrophysical Masers

    CERN Document Server

    Gray, Malcolm; Maccalli, Stefania; Schemmel, Peter

    2014-01-01

    We extend the theory of astrophysical maser propagation through a medium with a Zeeman-split molecular response to the case of a non-uniform magnetic field, and allow a component of the electric field of the radiation in the direction of propagation: a characteristic of radiation with orbital angular momentum. A classical reduction of the governing equations leads to a set of nine differential equations for the evolution of intensity-like parameters for each Fourier component of the radiation. Four of these parameters correspond to the standard Stokes parameters, whilst the other five represent the $z$-component of the electric field, and its coupling to the conventional components in the $x-y$-plane. A restricted analytical solution of the governing equations demonstrates a non-trivial coupling of the Stokes parameters to those representing orbital angular momentum: the $z$-component of the electric field can grow from a background in which only Stokes-$I$ is non-zero. A numerical solution of the governing e...

  6. Fiber optic ionizing radiation detector

    Energy Technology Data Exchange (ETDEWEB)

    Suter, J.J. (Johns Hopkins Univ., Applied Physics Lab., Laurel, MD (United States)); Poret, J.C.; Rosen, M. (Johns Hopkins Univ., Dept. of Materials Science and Engineering, Baltimore, MD (United States))

    1992-08-01

    Radiation detection can be done by various types of devices, such as Geiger counters, thermoluminescent detectors, and electric field sensors. This paper reports on a noel design for an ionizing radiation sensor using coiled optical fibers, which can be placed within or near a radioactive source. This design has several features that make it different from sensors proposed in the past. In order to evaluate this sensor, coiled fiber samples were placed inside metallic and metal-matrix composite cylinders to evaluate the sensitivity of the detector as well as the shielding effectiveness of the materials.

  7. Leukemia and ionizing radiation revisited

    Energy Technology Data Exchange (ETDEWEB)

    Cuttler, J.M. [Cuttler & Associates Inc., Vaughan, Ontario (Canada); Welsh, J.S. [Loyola University-Chicago, Dept. or Radiation Oncology, Stritch School of Medicine, Maywood, Illinois (United States)

    2016-03-15

    A world-wide radiation health scare was created in the late 19508 to stop the testing of atomic bombs and block the development of nuclear energy. In spite of the large amount of evidence that contradicts the cancer predictions, this fear continues. It impairs the use of low radiation doses in medical diagnostic imaging and radiation therapy. This brief article revisits the second of two key studies, which revolutionized radiation protection, and identifies a serious error that was missed. This error in analyzing the leukemia incidence among the 195,000 survivors, in the combined exposed populations of Hiroshima and Nagasaki, invalidates use of the LNT model for assessing the risk of cancer from ionizing radiation. The threshold acute dose for radiation-induced leukemia, based on about 96,800 humans, is identified to be about 50 rem, or 0.5 Sv. It is reasonable to expect that the thresholds for other cancer types are higher than this level. No predictions or hints of excess cancer risk (or any other health risk) should be made for an acute exposure below this value until there is scientific evidence to support the LNT hypothesis. (author)

  8. Ionizing radiation and genetic risks

    Energy Technology Data Exchange (ETDEWEB)

    Sankaranarayanan, K. [Department of Toxicogenetics, Leiden University Medical Centre, Sylvius Laboratories, Wassenaarseweg 72, 2333 AL Leiden (Netherlands)]. E-mail: sankaran@lumc.nl; Wassom, J.S. [YAHSGS, LLC, Richland, WA 99352 (United States); Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830 (United States)

    2005-10-15

    Recent estimates of genetic risks from exposure of human populations to ionizing radiation are those presented in the 2001 report of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). These estimates incorporate two important concepts, namely, the following: (1) most radiation-induced mutations are DNA deletions, often encompassing multiple genes, but only a small proportion of the induced deletions is compatible with offspring viability; and (2) the viability-compatible deletions induced in germ cells are more likely to manifest themselves as multi-system developmental anomalies rather than as single gene disorders. This paper: (a) pursues these concepts further in the light of knowledge of mechanisms of origin of deletions and other rearrangements from two fields of contemporary research: repair of radiation-induced DNA double-strand breaks (DSBs) in mammalian somatic cells and human molecular genetics; and (b) extends them to deletions induced in the germ cell stages of importance for radiation risk estimation, namely, stem cell spermatogonia in males and oocytes in females. DSB repair studies in somatic cells have elucidated the roles of two mechanistically distinct pathways, namely, homologous recombination repair (HRR) that utilizes extensive sequence homology and non-homologous end-joining (NHEJ) that requires little or no homology at the junctions. A third process, single-strand annealing (SSA), which utilizes short direct repeat sequences, is considered a variant of HRR. HRR is most efficient in late S and G{sub 2} phases of the cell cycle and is a high fidelity mechanism. NHEJ operates in all cell cycle phases, but is especially important in G{sub 1}. In the context of radiation-induced DSBs, NHEJ is error-prone. SSA is also an error-prone mechanism and its role is presumably similar to that of HRR. Studies in human molecular genetics have demonstrated that the occurrence of large deletions, duplications or other

  9. Bystander Effects of Ionizing Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Little, John B. [Harvard T.H. Chan School of Public Health, Boston, MA (United States). Dept. of Genetics and Complex Diseases

    2017-01-17

    The objectives of this grant renewal are to provide administrative support and travel funds to allow the continued participation of the principal investigator (Dr. John B. Little) as an advisor to research initiated by several research fellows from his laboratory. The actual research will be carried out under the direction of Dr. Hatsumi Nagasawa with the collaboration of Dr. Joel Bedford at the Colorado State University, and by Drs. Edouard Azzam and Sonia de Toledo at the University of Medicine and Dentistry of New Jersey. Dr. Little will advise on the planning of experiments and development of experimental protocols, the analysis of data, and the preparation of manuscripts for publication. The Specific Aims for several of the planned experiments include: 1) to extend studies of the role of recombinational repair in the bystander effect by examining other genes in this pathway and cell lines deficient in excision repair; 2) to continue studies to determine the nature of the damage signal transmitted to bystander cells including the expression of several connexins in the bystander response, and the extent to which the enhanced oxidative metabolism observed in bystander cells may relate to the nature of the transmitted bystander signal; 3) to utilize a genome-wide approach to examine the genetic basis for the hypersensitivity to ionization we have observed in unaffected parents of patients with hereditary retinoblastoma, as well as from a group of a apparently normal individuals that show similar radiosensitivity; 4) to complete studies concerning the induction of high frequencies of cells with massive chromosome damage in clonal derivatives of p53 and p21 knockout mouse cell lines; in particular to examine the role of telomere changes in this phenomenon. Overall, the results of these studies should enhance our understanding of the risk of low dose exposures to ionizing radiation, including human populations to residential radon as well as occupational exposures.

  10. Ametryne degradation by ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Debora Cristina de; Mori, Manoel Nunes; Duarte, Celina Lopes [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mails: deboracandrade@globo.com; mnmori@ipen.br; clduarte@ipen.br; Melo, Rita Paiva [Technological and Nuclear Institute (ITN), Sacavem (Portugal)]. E-mail: ritamelo@itn.pt

    2007-07-01

    Ametryne may be released to the environment during its manufacture, transport, storage, formulation and use as selective herbicide for the control of annual broadleaf and grass weeds. It is applied as an aqueous suspension for preemergence or post-directed applications on crops. Depending on the pesticide formulation and type of application, ametryne residues may be detectable in water, soil and on the surfaces for months or years. The herbicide used to this study was Ametryne (commercial name, Gesapax 500), commonly used on field crops and on corn and commercialized since 1975. Ametryne was analyzed by gas chromatography (GC Shimadzu 17A), after extraction with hexane/dichloromethane (1:1 v/v) solution. The calibration curve was obtained with a regression coefficient of 0.9871. In addition, the relative standard deviation was lower than 10%. The radiation-processing yield was evaluated by the destruction G-value (Gd) (Eq. 1), that is defined by the number of destroyed molecules by absorption of 100 eV of energy from ionizing radiation. Different concentrations of the herbicide (11.4 mol L{sup -1}; 22.7 mol L{sup -1}; 34.1 mol L{sup -1} and 45.5 mol L{sup -1}) were irradiated at the AECL 'Gammacell 220' {sup 60}Co source, with 1 kGy, 3 kGy, 6 kGy, 9 kGy, 12 kGy, 15 kGy and 30 kGy absorbed doses. After irradiation processing, the ametryne highest reduction rate occurs at low doses of radiation: at 6 kGy more than 85-90% of all ametryne compounds were removed. Two products of incomplete degradation of ametryne were identified as s-triazyne isomers. However, further work is needed in order to fully understand the ametryne degradation mechanisms the degradation yield of ametryne depends on its initial concentration and the process seems to be more efficient at higher concentrations. (author)

  11. Monitoring occupational exposure to ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Button, J.B.C. [Radiation Safety Consultancy, Engadine, NSW (Australia)

    1997-12-31

    A brief overview is presented of methods of monitoring occupational exposure to ionizing radiation together with reasons for such monitoring and maintaining dose histories of radiation occupationally exposed persons. The various Australian providers of external radiation monitoring services and the types of dosemeters they supply are briefly described together with some monitoring results. Biological monitoring methods, are used to determine internal radiation dose. Whole body monitors, used for this purpose are available at Australian Radiation Lab., ANSTO and a few hospitals. Brief mention is made of the Australian National Radiation Dose Register and its objectives. 8 refs., 9 tabs.

  12. Mutational signatures of ionizing radiation in second malignancies

    OpenAIRE

    Behjati, Sam; Gundem, Gunes; Wedge, David C.; Roberts, Nicola D.; Tarpey, Patrick S.; Cooke, Susanna L; Van Loo, Peter; Alexandrov, Ludmil B; Ramakrishna, Manasa; Davies, Helen; Nik-Zainal, Serena; Hardy, Claire; Latimer, Calli; Raine, Keiran M.; Stebbings, Lucy

    2016-01-01

    Ionizing radiation is a potent carcinogen, inducing cancer through DNA damage. The signatures of mutations arising in human tissues following in vivo exposure to ionizing radiation have not been documented. Here, we searched for signatures of ionizing radiation in 12 radiation-associated second malignancies of different tumour types. Two signatures of somatic mutation characterize ionizing radiation exposure irrespective of tumour type. Compared with 319 radiation-naive tumours, radiation-ass...

  13. Modeling Pressure-Ionization of Hydrogen in the Context of Astrophysics

    CERN Document Server

    Saumon, D S; Wagner, D J; Xie, X

    1999-01-01

    The recent development of techniques for laser-driven shock compression of hydrogen has opened the door to the experimental determination of its behavior under conditions characteristic of stellar and planetary interiors. The new data probe the equation of state (EOS) of dense hydrogen in the complex regime of pressure ionization. The structure and evolution of dense astrophysical bodies depend on whether the pressure ionization of hydrogen occurs continuously or through a ``plasma phase transition'' (PPT) between a molecular state and a plasma state. For the first time, the new experiments constrain predictions for the PPT. We show here that the EOS model developed by Saumon and Chabrier can successfully account for the data, and we propose an experiment that should provide a definitive test of the predicted PPT of hydrogen. The usefulness of the chemical picture for computing astrophysical EOS and in modeling pressure ionization is discussed.

  14. Chemical protection against ionizing radiation. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Livesey, J.C.; Reed, D.J.; Adamson, L.F.

    1984-08-01

    The scientific literature on radiation-protective drugs is reviewed. Emphasis is placed on the mechanisms involved in determining the sensitivity of biological material to ionizing radiation and mechanisms of chemical radioprotection. In Section I, the types of radiation are described and the effects of ionizing radiation on biological systems are reviewed. The effects of ionizing radiation are briefly contrasted with the effects of non-ionizing radiation. Section II reviews the contributions of various natural factors which influence the inherent radiosensitivity of biological systems. Inlcuded in the list of these factors are water, oxygen, thiols, vitamins and antioxidants. Brief attention is given to the model describing competition between oxygen and natural radioprotective substances (principally, thiols) in determining the net cellular radiosensitivity. Several theories of the mechanism(s) of action of radioprotective drugs are described in Section III. These mechanisms include the production of hypoxia, detoxication of radiochemical reactive species, stabilization of the radiobiological target and the enhancement of damage repair processes. Section IV describes the current strategies for the treatment of radiation injury. Likely areas in which fruitful research might be performed are described in Section V. 495 references.

  15. Chemical Protection Against Ionizing Radiation.

    Science.gov (United States)

    1984-08-01

    experimentally obtained. SPONSOR: Div of Cancer Treatment, NIH /A TOPICS: 2D PI/ORG: Moss, Alfred J; Veterans Administration Ned Ctr, Little Rock AR TITLE...Robert C; Dartmouth- Hitchcock Ned Ctr, Hanover NH TITLE: Radiation-chemical induction of mutagenesis. SUMMARY: Effects of sensitizers on radiation

  16. Diffuse ionizing radiation within HH jets

    Energy Technology Data Exchange (ETDEWEB)

    Esquivel, A.; Raga, A. C., E-mail: esquivel@nucleares.unam.mx, E-mail: raga@nucleares.unam.mx [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Apartado Postal 70-543, 04510 Mexico D.F. (Mexico)

    2013-12-20

    We present numerical hydrodynamical simulations of a time-dependent ejection velocity precessing jet. The parameters used in our models correspond to a high excitation Herbig-Haro object, such as HH 80/81. We have included the transfer of ionizing radiation produced within the shocked regions of the jet. The radiative transfer is computed with a ray-tracing scheme from all the cells with an emissivity above a certain threshold. We show the development of a radiative precursor, and compare the morphology with a model without the diffuse radiation. Our simulations show that the morphology of the Hα emission is affected considerably if the diffuse ionizing radiation is accounted for. The predicted Hα position-velocity diagram (i.e., spatially resolved emission line profiles) from a model with the transfer of ionizing radiation has a relatively strong component at zero velocity, corresponding to the radiative precursor. Qualitatively similar 'zero velocity components' are observed in HH 80/81 and in the jet from Sanduleak's star in the Large Magellanic Cloud.

  17. Composite scintillators for detection of ionizing radiation

    Science.gov (United States)

    Dai, Sheng [Knoxville, TN; Stephan, Andrew Curtis [Knoxville, TN; Brown, Suree S [Knoxville, TN; Wallace, Steven A [Knoxville, TN; Rondinone, Adam J [Knoxville, TN

    2010-12-28

    Applicant's present invention is a composite scintillator having enhanced transparency for detecting ionizing radiation comprising a material having optical transparency wherein said material comprises nano-sized objects having a size in at least one dimension that is less than the wavelength of light emitted by the composite scintillator wherein the composite scintillator is designed to have selected properties suitable for a particular application.

  18. Roles of ionizing radiation in cell transformation

    Energy Technology Data Exchange (ETDEWEB)

    Tobias, C.A.; Albright, N.W.; Yang, T.C.

    1983-07-01

    Earlier the authors described a repair misrepair model (RMR-I) which is applicable for radiations of low LET, e.g., x rays and gamma rays. RMR-II was described later. Here is introduced a mathematical modification of the RMR model, RMR-III, which is intended to describe lethal effects caused by heavily ionizing tracks. 31 references, 4 figures.

  19. Ionizing radiation induces stemness in cancer cells.

    Directory of Open Access Journals (Sweden)

    Laura Ghisolfi

    Full Text Available The cancer stem cell (CSC model posits the presence of a small number of CSCs in the heterogeneous cancer cell population that are ultimately responsible for tumor initiation, as well as cancer recurrence and metastasis. CSCs have been isolated from a variety of human cancers and are able to generate a hierarchical and heterogeneous cancer cell population. CSCs are also resistant to conventional chemo- and radio-therapies. Here we report that ionizing radiation can induce stem cell-like properties in heterogeneous cancer cells. Exposure of non-stem cancer cells to ionizing radiation enhanced spherogenesis, and this was accompanied by upregulation of the pluripotency genes Sox2 and Oct3/4. Knockdown of Sox2 or Oct3/4 inhibited radiation-induced spherogenesis and increased cellular sensitivity to radiation. These data demonstrate that ionizing radiation can activate stemness pathways in heterogeneous cancer cells, resulting in the enrichment of a CSC subpopulation with higher resistance to radiotherapy.

  20. Radiation Generated by Charge Migration Following Ionization

    CERN Document Server

    Kuleff, Alexander I

    2010-01-01

    Electronic many-body effects alone can be the driving force for an ultrafast migration of a positive charge created upon ionization of molecular systems. Here we show that this purely electronic phenomenon generates a characteristic IR radiation. The situation when the initial ionic wave packet is produced by a sudden removal of an electron is also studied. It is shown that in this case a much stronger UV emission is generated. This emission appears as an ultrafast response of the remaining electrons to the perturbation caused by the sudden ionization and as such is a universal phenomenon to be expected in every multielectron system.

  1. Responsive copolymer films obtained by ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Burillo, G.; Bucio, E. [Departamento de Quimica de Radiaciones y Radioquimica, Instituto de Ciencias Nucleares, UNAM, Circuito Exterior, Ciudad Universitaria, Mexico 04510, D. F. (Mexico)], e-mail: burillo@nucleares.unam.mx

    2009-07-01

    The graft copolymerization of ph and/or thermo sensitive monomers onto polymeric films can be achieved by different radiation methods which have great advantages compared to conventional methods. Their ph and thermal sensitivity properties, as well as LCST and critical ph point, have been studied by DSC, UV, FTIR, water contact angle and swelling. Graft copolymerization can be carried out by pre-irradiation oxidative and direct methods, using {sup 6}0Co gamma radiation or a Van de Graaff electron beam accelerator. The influence of synthesis conditions, such as pre-irradiation or radiation doses, dose rate, reaction time, monomer concentration, and reaction temperature are being studied. Advances in the field of responsive polymeric systems synthesized by ionizing radiation, their applications and promising future research on radiation graft polymerization and crosslinking will be discussed. (Author)

  2. Ionizing radiation detector using multimode optical fibers

    Energy Technology Data Exchange (ETDEWEB)

    Suter, J.J. (Johns Hopkins Univ., Laurel, MD (United States). Applied Physics Lab.); Poret, J.C.; Rosen, M. (Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Materials Science and Engineering); Rifkind, J.M. (National Inst. of Health, Baltimore, MD (United States). Lab. of Cellular and Molecular Biology)

    1993-08-01

    An optical ionizing radiation detector, based on the attenuation of 850-nm light in 50/125-[mu]m multimode fibers, is described. The detector is especially well suited for application on spacecraft because of its small design. The detection element consists of a section of coiled fibers that has been designed to strip higher-order optical modes. Cylindrical radiation shields with atomic numbers ranging from Z = 13 (aluminum too) Z = 82 (lead) were placed around the ionizing radiation detector so that the effectiveness of the detector could be measured. By exposing the shields and the detector to 1.25-MeV cobalt 60 radiation, the mass attenuation coefficients of the shields were measured. The detector is based on the phenomenon that radiation creates optical color centers in glass fibers. Electron spin resonance spectroscopy performed on the 50/125-[mu]m fibers showed the presence of germanium oxide and phosphorus-based color centers. The intensity of these centers is directly related to the accumulated gamma radiation.

  3. Annual Report: Hydrodynamics and Radiative Hydrodynamics with Astrophysical Applications

    Energy Technology Data Exchange (ETDEWEB)

    R. Paul Drake

    2005-12-01

    We report the ongoing work of our group in hydrodynamics and radiative hydrodynamics with astrophysical applications. During the period of the existing grant, we have carried out two types of experiments at the Omega laser. One set of experiments has studied radiatively collapsing shocks, obtaining high-quality scaling data using a backlit pinhole and obtaining the first (ever, anywhere) Thomson-scattering data from a radiative shock. Other experiments have studied the deeply nonlinear development of the Rayleigh-Taylor (RT) instability from complex initial conditions, obtaining the first (ever, anywhere) dual-axis radiographic data using backlit pinholes and ungated detectors. All these experiments have applications to astrophysics, discussed in the corresponding papers either in print or in preparation. We also have obtained preliminary radiographs of experimental targets using our x-ray source. The targets for the experiments have been assembled at Michigan, where we also prepare many of the simple components. The above activities, in addition to a variety of data analysis and design projects, provide good experience for graduate and undergraduates students. In the process of doing this research we have built a research group that uses such work to train junior scientists.

  4. Bacterial and archaeal resistance to ionizing radiation

    Science.gov (United States)

    Confalonieri, F.; Sommer, S.

    2011-01-01

    Organisms living in extreme environments must cope with large fluctuations of temperature, high levels of radiation and/or desiccation, conditions that can induce DNA damage ranging from base modifications to DNA double-strand breaks. The bacterium Deinococcus radiodurans is known for its resistance to extremely high doses of ionizing radiation and for its ability to reconstruct a functional genome from hundreds of radiation-induced chromosomal fragments. Recently, extreme ionizing radiation resistance was also generated by directed evolution of an apparently radiation-sensitive bacterial species, Escherichia coli. Radioresistant organisms are not only found among the Eubacteria but also among the Archaea that represent the third kingdom of life. They present a set of particular features that differentiate them from the Eubacteria and eukaryotes. Moreover, Archaea are often isolated from extreme environments where they live under severe conditions of temperature, pressure, pH, salts or toxic compounds that are lethal for the large majority of living organisms. Thus, Archaea offer the opportunity to understand how cells are able to cope with such harsh conditions. Among them, the halophilic archaeon Halobacterium sp and several Pyrococcus or Thermococcus species, such as Thermococcus gammatolerans, were also shown to display high level of radiation resistance. The dispersion, in the phylogenetic tree, of radioresistant prokaryotes suggests that they have independently acquired radioresistance. Different strategies were selected during evolution including several mechanisms of radiation byproduct detoxification and subtle cellular metabolism modifications to help cells recover from radiation-induced injuries, protection of proteins against oxidation, an efficient DNA repair tool box, an original pathway of DNA double-strand break repair, a condensed nucleoid that may prevent the dispersion of the DNA fragments and specific radiation-induced proteins involved in

  5. Alloy nanoparticle synthesis using ionizing radiation

    Science.gov (United States)

    Nenoff, Tina M.; Powers, Dana A.; Zhang, Zhenyuan

    2011-08-16

    A method of forming stable nanoparticles comprising substantially uniform alloys of metals. A high dose of ionizing radiation is used to generate high concentrations of solvated electrons and optionally radical reducing species that rapidly reduce a mixture of metal ion source species to form alloy nanoparticles. The method can make uniform alloy nanoparticles from normally immiscible metals by overcoming the thermodynamic limitations that would preferentially produce core-shell nanoparticles.

  6. Measuring ionizing radiation with a mobile device

    Science.gov (United States)

    Michelsburg, Matthias; Fehrenbach, Thomas; Puente León, Fernando

    2012-02-01

    In cases of nuclear disasters it is desirable to know one's personal exposure to radioactivity and the related health risk. Usually, Geiger-Mueller tubes are used to assess the situation. Equipping everyone with such a device in a short period of time is very expensive. We propose a method to detect ionizing radiation using the integrated camera of a mobile consumer device, e.g., a cell phone. In emergency cases, millions of existing mobile devices could then be used to monitor the exposure of its owners. In combination with internet access and GPS, measured data can be collected by a central server to get an overview of the situation. During a measurement, the CMOS sensor of a mobile device is shielded from surrounding light by an attachment in front of the lens or an internal shutter. The high-energy radiation produces free electrons on the sensor chip resulting in an image signal. By image analysis by means of the mobile device, signal components due to incident ionizing radiation are separated from the sensor noise. With radioactive sources present significant increases in detected pixels can be seen. Furthermore, the cell phone application can make a preliminary estimate on the collected dose of an individual and the associated health risks.

  7. A website dedicated to ionizing radiation metrology.

    Science.gov (United States)

    Dulieu, Christophe; Chisté, Vanessa; Bé, Marie-Martine

    2004-01-01

    In order to disseminate information about decay data and their evaluation, as well as other topics in the field of ionizing radiation, the Bureau National de Métrologie-Laboratoire National Henri Becquerel (BNM-LNHB) has published a website. Most of the web pages are concerned with the international working groups in which the BNM-LNHB takes part. In particular, a library of uranium and plutonium spectra is now available, as well as the results of evaluation of decay data of nuclides of special interest.

  8. Radiative ablation with two ionizing-fronts when opacity displays a sharp absorption edge

    CERN Document Server

    Poujade, Olivier; Vandenboomgaerde, Marc

    2014-01-01

    The interaction of a strong flux of photons with matter through an ionizing-front (I-front) is an ubiquitous phenomenon in the context of astrophysics and inertial confinement fusion (ICF) where intense sources of radiation put matter into motion. When the opacity of the irradiated material varies continuously in the radiation spectral domain, only one single I-front is formed. In contrast, as numerical simulations tend to show, when the opacity of the irradiated material presents a sharp edge in the radiation spectral domain, a second I-front (an edge-front) can form. A full description of the mechanism behind the formation of this edge-front is presented in this article. It allows to understand supernumerary shocks (edge-shocks), displayed by ICF simulations, that might affect the robustness of the design of fusion capsules in actual experiments. Moreover, it may have consequences in various domains of astrophysics where ablative flows occur.

  9. Antihistamine provides sex-specific radiation protection. [Ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Mickley, G.A.

    1981-04-01

    Rats suffer an early transient performance decrement immediately after a sufficiently large dose of ionizing radiation. However, it has been shown that males experience a more severe incapacitation than females. This sex difference has been attributed to the low estrogen levels in the male. In support of this notion, supplemental estrogens in castrated male rats have produced less-severe performance decrements post-irradiation. Antihistamines have also previously been shown to alleviate radiation's effect on behavior. The present study revealed that antihistamines are only effective in altering the behavioral incapacitation of sexually intact male subjects. This contrasts with previous work which indicates that estrogens can only benefit gonadectomized rats. These findings suggest that different mechanisms may underlie antihistamine and estrogen radiation protection.

  10. Storage-ring ionization and recombination experiments with multiply charged ions relevant to astrophysical and fusion plasmas

    CERN Document Server

    Schippers, Stefan

    2011-01-01

    Past and ongoing research activities at the Heidelberg heavy-ion storage-ring TSR are reviewed which aim at providing accurate absolute rate coefficients and cross sections of atomic collision processes for applications in astrophysics and magnetically confined fusion. In particular, dielectronic recombination and electron impact ionization of iron ions are discussed as well as dielectronic recombination of tungsten ions.

  11. Low Dose Ionizing Radiation Modulates Immune Function

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Gregory A. [Loma Linda Univ., CA (United States)

    2016-01-12

    In order to examine the effects of low dose ionizing radiation on the immune system we chose to examine an amplified adaptive cellular immunity response. This response is Type IV delayed-type hypersensitivity also called contact hypersensitivity. The agent fluorescein isothiocyanate (FITC) is a low molecular weight, lipophilic, reactive, fluorescent molecule that can be applied to the skin where it (hapten) reacts with proteins (carriers) to become a complete antigen. Exposure to FITC leads to sensitization which is easily measured as a hypersensitivity inflammatory reaction following a subsequent exposure to the ear. Ear swelling, eosinophil infiltration, immunoglobulin E production and cytokine secretion patterns characteristic of a “Th2 polarized” immune response are the components of the reaction. The reaction requires successful implementation of antigen processing and presentation by antigen presenting Langerhans cells, communication with naïve T lymphocytes in draining lymph nodes, expansion of activated T cell clones, migration of activated T cells to the circulation, and recruitment of memory T cells, macrophages and eosinophils to the site of the secondary challenge. Using this model our approach was to quantify system function rather than relying only on indirect biomarkers of cell. We measured the FITC-induced hypersensitivity reaction over a range of doses from 2 cGy to 2 Gy. Irradiations were performed during key events or prior to key events to deplete critical cell populations. In addition to quantifying the final inflammatory response, we assessed cell populations in peripheral blood and spleen, cytokine signatures, IgE levels and expression of genes associated with key processes in sensitization and elicitation/recall. We hypothesized that ionizing radiation would produce a biphasic effect on immune system function resulting in an enhancement at low doses and a depression at higher doses and suggested that this transition would occur in the

  12. Fungi and ionizing radiation from radionuclides.

    Science.gov (United States)

    Dighton, John; Tugay, Tatyana; Zhdanova, Nelli

    2008-04-01

    Radionuclides in the environment are one of the major concerns to human health and ecotoxicology. The explosion at the Chernobyl nuclear power plant renewed interest in the role played by fungi in mediating radionuclide movement in ecosystems. As a result of these studies, our knowledge of the importance of fungi, especially in their mycorrhizal habit, in long-term accumulation of radionuclides, transfer up the food chain and regulation of accumulation by their host plants was increased. Micro-fungi have been found to be highly resilient to exposure to ionizing radiation, with fungi having been isolated from within and around the Chernobyl plant. Radioresistance of some fungal species has been linked to the presence of melanin, which has been shown to have emerging properties of acting as an energy transporter for metabolism and has been implicated in enhancing hyphal growth and directed growth of sensitized hyphae towards sources of radiation. Using this recently acquired knowledge, we may be in a better position to suggest the use of fungi in bioremediation of radioactively contaminated sites and cleanup of industrial effluent.

  13. Ionizing Radiation in Glioblastoma Initiating Cells

    Directory of Open Access Journals (Sweden)

    Maricruz eRivera

    2013-04-01

    Full Text Available Glioblastoma is the most common primary malignant brain tumor in adults with a median survival of 12-15 months with treatment consisting of surgical resection followed by ionizing radiation (IR and chemotherapy. Even aggressive treatment is often palliative due to near universal recurrence. Therapeutic resistance has been linked to a subpopulation of GBM cells with stem-cell like properties termed glioblastoma initiating cells (GICs. Recent efforts have focused on elucidating resistance mechanisms activated in GICs in response to IR. Among these, GICs preferentially activate the DNA damage response (DDR to result in a faster rate of double-strand break (DSB repair induced by IR as compared to the bulk tumor cells. IR also activates NOTCH and the hepatic growth factor (HGF receptor, c-MET, signaling cascades that play critical roles in promoting proliferation, invasion, and resistance to apoptosis. These pathways are preferentially activated in GICs and represent targets for pharmacologic intervention. While IR provides the benefit of improved survival, it paradoxically promotes selection of more malignant cellular phenotypes of glioblastoma. As reviewed here, finding effective combinations of radiation and molecular inhibitors to target GICs and non-GICs is essential for the development of more effective therapies.

  14. Genetic variation in resistance to ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ayala, F.J.

    1992-01-01

    Results of an investigation of the gene coding for Cu, Zn superoxide dismutase (Sod) in Drosophila melanogaster seeking to understand the enzyme's role in cell protection against ionizing radiation are reported. Components of the investigation include molecular characterization of the gene; measuring the response of different genotypes to increasing levels of radiation; and investigation of the processes that maintain the Sod polymorphism in populations. While two alleles, S and F, are commonly found at the Sod locus in natural populations of D. melanogaster we have isolated from a natural population a null (CA1) mutant that yields only 3.5% of normal SOD activity. The S, F, and CA1 alleles provide a model system to investigate SOD-dependent radioresistance, because each allele yields different levels of SOD, so that S > F >> CAl. The radioprotective effects of SOD can be established by showing protective effects for the various genotypes that correspond to those inequalities. Because the allele variants studied are derived from natural populations, the proposed investigation avoids problems that arise when mutants obtained my mutagenesis are used. Moreover, each allele is studied in multiple genetic backgrounds, so that we correct for effects attributable to other loci by randomizing these effects.

  15. Using the FMA for radiative capture cross-section measurements of interest to astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Davids, C.N.; Back, B.B.; Blumenthal, D.J. [and others

    1995-08-01

    We assessed the capability of the Fragment Mass Analyzer (FMA) to study radiative capture reactions of astrophysical interest using inverse kinematics. Results from measurements on the {sup 1}H({sup 13}C,{sup 14}N){gamma} reaction show that the FMA is an ideal high-efficiency tool for these experiments, where the recoil ion is detected and identified at the FMA focal plane. Intermediate slits acting on energy/charge and mass/charge were introduced into the FMA, which reduced the scattered primary beam fraction at the focal plane to <10{sup -11}. A small gas ionization chamber was placed behind the position-sensitive focal-plane detector, followed by a Si detector. Measurements of mass/charge, energy loss, and residual energy of the transmitted ions were made, giving at least another two orders of magnitude separation of recoils from scattered beam. A new ionization detector operating in the same gas volume as the focal plane detector will provide even better separation by eliminating the need for two of the three windows used in the test measurement. At energies of {approximately} 0.5 MeV/nucleon, the recoil ions populate primarily a single charge state, resulting in a detection efficiency of > 50%. This will be particularly valuable for use with radioactive beams.

  16. Role of the UV external radiation field on the presence of astrophysical ices in protostellars environments

    Science.gov (United States)

    Robson Monteiro Rocha, Will; Pilling, Sergio

    2016-07-01

    The astrophysical ices survival is directly related with the temperature and ionizing radiation field in protostellars environments such as disks and envelopes. Computational models has shown that pure volatile molecules like CO and CH _{4} should survive only inside densest regions of molecular clouds or protoplanetary disks On the other hand, solid molecules such as H _{2}O and CH _{3}OH can be placed around 5 - 10 AU from the central protostar. Unlike of the previous models, we investigate the role of the UV external radiation field on the presence of ices in disks and envelopes. Once that a star-forming region is composed by the formation of many protostars, the external radiation field should be an important component to understand the real localization of the ices along the sight line. To address this topic it was employed the radiative transfer code RADMC-3D based on the Monte Carlo method. The code was used to model the spectrum and the near-infrared image of Elias 29. The initial parameters of the disk and envelope was taken from our previous paper (Rocha & Pilling (2015), ApJ 803:18). The opacities of the ices were calculated from the complex refractive index obtained at laboratory experiments perfomed at Grand Accélerateur National d'Íons Lourds (GANIL), by using the NKABS code from Rocha & Pilling (2014), SAA 123:436. The partial conclusions that we have obtained shows that pure CO volatile molecule cannot be placed at disk or envelope of Elias 29, unlike shown in our paper about Elias 29. Once it was observed in Elias 29 spectrum obtained with Infrared Space Observatory (ISO) between 2.5 - 190 μm, this molecule should be placed in foreground molecular clouds or trapped in the water ice matrix. The next calculations will be able to show where are placed the ices such as CH _{3}OH and CH _{3}CHO observed in Elias 29 spectrum.

  17. Low dose ionizing radiation induced acoustic neuroma: A putative link?

    Directory of Open Access Journals (Sweden)

    Sachin A Borkar

    2012-01-01

    Full Text Available Although exposure to high dose ionizing radiation (following therapeutic radiotherapy has been incriminated in the pathogenesis of many brain tumors, exposure to chronic low dose ionizing radiation has not yet been shown to be associated with tumorigenesis. The authors report a case of a 50-year-old atomic reactor scientist who received a cumulative dose of 78.9 mSv over a 10-year period and was detected to have an acoustic neuroma another 15 years later. Although there is no proof that exposure to ionizing radiation was the cause for the development of the acoustic neuroma, this case highlights the need for extended follow-up periods following exposure to low dose ionizing radiation.

  18. Performance studies of scintillating ceramic samples exposed to ionizing radiation

    CERN Document Server

    Dissertori, G; Nessi-Tedaldi, F; Wallny, R

    2014-01-01

    Scintillating ceramics are a promising, new development for various applications in science and industry. Their application in calorimetry for particle physics experiments is expected to involve an exposure to high levels of ionizing radiation. In this paper, changes in performance have been measured for scintillating ceramic samples of different composition after exposure to penetrating ionizing radiation up to a dose of 38 kGy. 2012 IEEE Nuclear Science Symposium Conference Record

  19. Performance studies of scintillating ceramic samples exposed to ionizing radiation

    CERN Document Server

    Dissertori, G; Nessi-Tedaldi, F; Pauss, F; Wallny, R

    2012-01-01

    Scintillating ceramics are a promising, new development for various applications in science and industry. Their application in calorimetry for particle physics experiments is expected to involve an exposure to high levels of ionizing radiation. In this paper, changes in performance have been measured for scintillating ceramic samples of different composition after exposure to penetrating ionizing radiation up to a dose of 38 kGy.

  20. [Use of ionizing radiation sources in metallurgy: risk assessment].

    Science.gov (United States)

    Giugni, U

    2012-01-01

    Use of ionizing radiation sources in the metallurgical industry: risk assessment. Radioactive sources and fixed or mobile X-ray equipment are used for both process and quality control. The use of ionizing radiation sources requires careful risk assessment. The text lists the characteristics of the sources and the legal requirements, and contains a description of the documentation required and the methods used for risk assessment. It describes how to estimate the doses to operators and the relevant classification criteria used for the purpose of radiation protection. Training programs must be organized in close collaboration between the radiation protection expert and the occupational physician.

  1. Microscopic properties of xenon plasmas for density and temperature regimes of laboratory astrophysics experiments on radiative shocks.

    Science.gov (United States)

    Rodríguez, R; Espinosa, G; Gil, J M; Stehlé, C; Suzuki-Vidal, F; Rubiano, J G; Martel, P; Mínguez, E

    2015-05-01

    This work is divided into two parts. In the first one, a study of radiative properties (such as monochromatic and the Rosseland and Planck mean opacities, monochromatic emissivities, and radiative power loss) and of the average ionization and charge state distribution of xenon plasmas in a range of plasma conditions of interest in laboratory astrophysics and extreme ultraviolet lithography is performed. We have made a particular emphasis in the analysis of the validity of the assumption of local thermodynamic equilibrium and the influence of the atomic description in the calculation of the radiative properties. Using the results obtained in this study, in the second part of the work we have analyzed a radiative shock that propagated in xenon generated in an experiment carried out at the Prague Asterix Laser System. In particular, we have addressed the effect of plasma self-absorption in the radiative precursor, the influence of the radiation emitted from the shocked shell and the plasma self-emission in the radiative precursor, the cooling time in the cooling layer, and the possibility of thermal instabilities in the postshock region.

  2. Targeted and non-targeted effects of ionizing radiation

    Directory of Open Access Journals (Sweden)

    Omar Desouky

    2015-04-01

    Full Text Available For a long time it was generally accepted that effects of ionizing radiation such as cell death, chromosomal aberrations, DNA damage, mutagenesis, and carcinogenesis result from direct ionization of cell structures, particularly DNA, or from indirect damage through reactive oxygen species produced by radiolysis of water, and these biological effects were attributed to irreparable or misrepaired DNA damage in cells directly hit by radiation. Using linear non-threshold model (LNT, possible risks from exposure to low dose ionizing radiation (below 100 mSv are estimated by extrapolating from data obtained after exposure to higher doses of radiation. This model has been challenged by numerous observations, in which cells that were not directly traversed by the ionizing radiation exhibited responses similar to those of the directly irradiated cells. Therefore, it is nowadays accepted that the detrimental effects of ionizing radiation are not restricted only in the irradiated cells, but also to non-irradiated bystander or even distant cells manifesting various biological effects.

  3. 4T CMOS Active Pixel Sensors under Ionizing Radiation

    NARCIS (Netherlands)

    Tan, J.

    2013-01-01

    This thesis investigates the ionizing radiation effects on 4T pixels and the elementary in-pixel test devices with regard to the electrical performance and the optical performance. In addition to an analysis of the macroscopic pixel parameter degradation, the radiation-induced degradation mechanisms

  4. Biological effects of ionizing radiations; Effets biologiques des rayonnements ionisants

    Energy Technology Data Exchange (ETDEWEB)

    Nenot, J.C. [CEA Fontenay-aux-Roses, 92 (France). Inst. de Protection et de Surete Nucleaire]|[Commission Internationale de protection radiologique (France)]|[Association Internationale de Radiopathologie (France)

    1999-01-01

    Since ten years the ionizing radiations are more and more often used in various domains as medical, industrial or research sector. In the same way, these radiation impacts on the environment and the living organisms, have been studied intensively. The effects mechanism knowledge improved considerably and allowed to better protect the workers and the public. (A.L.B.)

  5. Adaptation hypothesis of biological effectiveness of ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kudritsky, Yu.K.; Georgievsky, A.B.; Karpov, V.I.

    1993-12-31

    The adoptation hypothesis of biological effectiveness of ionizing radiations is based on the recognition of the invariability of general biological laws for radiobiology and on the comprehension of life evolution regularities and axiomatic principles of environment and biota unity. The ionizing radiation factor is essential for life which could not exist beyond the radiation field. The possibility of future development of the adaptation hypothesis serves as a basis for it`s transformation into the theoretical foundation of radiobiology. This report discusses the aspects of the adaptation theory.

  6. Testing astrophysical radiation hydrodynamics codes with hypervelocity jet experiments on the nova laser

    Energy Technology Data Exchange (ETDEWEB)

    Estabrook, K; Farley, D; Glendinning, S G; Remington, B A; Stone, J; Turner, N

    1999-09-22

    Recent shock tube experiments using the Nova laser facility have demonstrated that strong shocks and highly supersonic flows similar to those encountered in astrophysical jets can be studied in detail through carefully controlled experiment. We propose the use of high power lasers such as Nova, Omega, and NIF to perform experiments on radiation hydrodynamic problems such as jets involving the multidimensional dynamics of strong shocks. High power lasers are the only experimental facilities that can reach the very high Mach number regime. The experiments will serve both as diagnostics of astrophysically interesting gas dynamic problems, and could also form the basis of test problems for numerical algorithms for astrophysical radiation hydrodynamic codes, The potential for experimentally achieving a strongly radiative jet seems very good.

  7. Effect of ionizing radiation on advanced life support medications

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, D.J.; Hubbard, L.B.; Broadbent, M.V.; Stewart, P.; Jaeger, M.

    1987-06-01

    Advanced life support medications stored in emergency department stretcher areas, diagnostic radiology rooms, and radiotherapy suites are exposed to ionizing radiation. We hypothesized that radiation may decrease the potency and thus the shelf life of medications stored in these areas. Atropine, dopamine, epinephrine, and isoproterenol were exposed to a wide range of ionizing radiation. The potency of the four drugs was unaffected by levels of radiation found in ED stretcher areas and high-volume diagnostic radiograph rooms (eg, chest radiograph, computed tomography, fluoroscopy). The potency of atropine may be reduced by gamma radiation in high-use radiotherapy suites. However, dopamine, epinephrine, and isoproterenol were unaffected by high doses of gamma radiation. Atropine, dopamine, epinephrine, and isoproterenol may be safely kept in ED stretcher areas and diagnostic radiology rooms without loss of potency over the shelf life of the drugs.

  8. Application of Lead Sulphide Nanoparticles for Dosimetry of Ionizing Radiation

    OpenAIRE

    Dehtjars, J; Kovaļovs, P; Reisfeld, R.; Rešetņikova, A; Romanova, M.; Saraidarov, T; Surkova, I

    2015-01-01

    The aim of the research is to design a dosimeter that provides measurements of doses of ionizing radiation absorbed in nano-sized objects. Such dosimeters can be useful for radiobiology in order to study effects of radiation on nanosized biological structures such as DNA molecule. We offer to use radiation-sensitive semiconductor nanoparticles as nanosized active elements of the dosimeter. Nanoparticles have to be embedded into a dielectric matrix that provides physical and chemical stabil...

  9. Effects of ionizing radiation; Effecten van ioniserende straling

    Energy Technology Data Exchange (ETDEWEB)

    Loos, M.; Hardeman, F.; Holmstock, L.; Hurtgen, C.; Mahieu, L.; Sohier, A.; Vandecasteele, C.; Vanhavere, F.; Vanmaercke, H.; Zeevaert, T

    1998-12-01

    Starting with a brief introduction to radiation protection, the report gives an overview of exposure to ionising radiation in Belgium due to activities in relation to the nuclear fuel cycle, processing and disposal of radioactive waste and other artificial or natural sources. Where appropriate, the Belgian situation discussed from an international perspective. The radiological impact of reprocessing and non-reprocessing are compared. The biological effects of ionizing radiation, epidemiological studies as well as surveillance programmes on the Belgian territory are reported on.

  10. Losartan sensitizes selectively prostate cancer cell to ionizing radiation.

    Science.gov (United States)

    Yazdannejat, H; Hosseinimehr, S J; Ghasemi, A; Pourfallah, T A; Rafiei, A

    2016-01-11

    Losartan is an angiotensin II receptor (AT-II-R) blocker that is widely used by human for blood pressure regulation. Also, it has antitumor property. In this study, we investigated the radiosensitizing effect of losartan on cellular toxicity induced by ionizing radiation on prostate cancer and non-malignant fibroblast cells. Human prostate cancer (DU-145) and human non-malignant fibroblast cells (HFFF2) were treated with losartan at different concentrations (0.5, 1, 10, 50 and 100 µM) and then these cells were exposed to ionizing radiation. The cell proliferation was determined using MTT assay. Our results showed that losartan exhibited antitumor effect on prostate cancer cells; it was reduced cell survival to 66% at concentration 1 µM. Losartan showed an additive killing effect in combination with ionizing radiation on prostate cancer cell. The cell proliferation was reduced to 54% in the prostate cancer cells treated with losartan at concentration 1 µM in combination with ionizing radiation. Losartan did not exhibit any toxicity on HFFF2 cell. This result shows a promising effect of losartan on enhancement of therapeutic effect of ionizing radiation in patients during therapy.

  11. Synergistic effect of ozonation and ionizing radiation for PVA decomposition.

    Science.gov (United States)

    Sun, Weihua; Chen, Lujun; Zhang, Yongming; Wang, Jianlong

    2015-08-01

    Ozonation and ionizing radiation are both advanced oxidation processes (AOPs) without chemical addition and secondary pollution. Also, the two processes' efficiency is determined by different pH conditions, which creates more possibilities for their combination. Importantly, the combined process of ozonation and ionizing radiation could be suitable for treating wastewaters with extreme pH values, i.e., textile wastewater. To find synergistic effects, the combined process of ozonation and ionizing radiation mineralization was investigated for degradation of polyvinyl alcohol (PVA) at different pH levels. A synergistic effect was found at initial pH in the range 3.0-9.4. When the initial pH was 3.0, the combined process of ozonation and ionizing radiation gave a PVA mineralization degree of 17%. This was 2.7 times the sum achieved by the two individual processes, and factors of 2.1 and 1.7 were achieved at initial pH of 7.0 and 9.4, respectively. The combined process of ozonation and ionizing radiation was demonstrated to be a feasible strategy for treatment of PVA-containing wastewater.

  12. Space Weather Nowcasting of Atmospheric Ionizing Radiation for Aviation Safety

    Science.gov (United States)

    Mertens, Christopher J.; Wilson, John W.; Blattnig, Steve R.; Solomon, Stan C.; Wiltberger, J.; Kunches, Joseph; Kress, Brian T.; Murray, John J.

    2007-01-01

    There is a growing concern for the health and safety of commercial aircrew and passengers due to their exposure to ionizing radiation with high linear energy transfer (LET), particularly at high latitudes. The International Commission of Radiobiological Protection (ICRP), the EPA, and the FAA consider the crews of commercial aircraft as radiation workers. During solar energetic particle (SEP) events, radiation exposure can exceed annual limits, and the number of serious health effects is expected to be quite high if precautions are not taken. There is a need for a capability to monitor the real-time, global background radiations levels, from galactic cosmic rays (GCR), at commercial airline altitudes and to provide analytical input for airline operations decisions for altering flight paths and altitudes for the mitigation and reduction of radiation exposure levels during a SEP event. The Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) model is new initiative to provide a global, real-time radiation dosimetry package for archiving and assessing the biologically harmful radiation exposure levels at commercial airline altitudes. The NAIRAS model brings to bear the best available suite of Sun-Earth observations and models for simulating the atmospheric ionizing radiation environment. Observations are utilized from ground (neutron monitors), from the atmosphere (the METO analysis), and from space (NASA/ACE and NOAA/GOES). Atmospheric observations provide the overhead shielding information and the ground- and space-based observations provide boundary conditions on the GCR and SEP energy flux distributions for transport and dosimetry simulations. Dose rates are calculated using the parametric AIR (Atmospheric Ionizing Radiation) model and the physics-based HZETRN (High Charge and Energy Transport) code. Empirical models of the near-Earth radiation environment (GCR/SEP energy flux distributions and geomagnetic cut-off rigidity) are benchmarked

  13. Effect of ionizing radiation on rat parotid gland

    Energy Technology Data Exchange (ETDEWEB)

    Boraks, George; Tampelini, Flavio Silva; Pereira, Kleber Fernando; Chopard, Renato Paulo [University of Sao Paulo (USP), SP (Brazil). Inst. of Biomedical Sciences. Dept. of Anatomy]. E-mail: rchopard@usp.br

    2008-01-15

    A common side effect of radiotherapy used in the treatment of oral cancer is the occurrence of structural and physiological alterations of the salivary glands due to exposure to ionizing radiation, as demonstrated by conditions such as decreased salivary flow. The present study evaluated ultrastructural alterations in the parotid glands of rats receiving a fractionated dose (1,500-cGy) of radiation emitted by a Cesium-137 source and rats that were not subjected to ionizing radiation. After sacrifice, the parotid glands were removed and examined by transmission electron microscopy. Damage such as cytoplasmic vacuolisation, dilatation of the endoplasmic reticulum and destruction of mitochondria, as well as damage to the cellular membrane of acinar cells, were observed. These findings lead to the conclusion that ionizing radiation promotes alterations in the glandular parenchyma, and that these alterations are directly related to the dose level of absorbed radiation. Certain phenomena that appear in the cytoplasm and nuclear material indicate that ionizing radiation causes acinar cell death (apoptosis). (author)

  14. Mammalian cells exposed to ionizing radiation: structural and biochemical aspects

    Energy Technology Data Exchange (ETDEWEB)

    Sabanero, M.; Flores V, L. L. [Universidad de Guanajuato, Departamento de Biologia, DCNE, Noria Alta s/n, 36250 Guanajuato, Gto. (Mexico); Azorin V, J. C.; Vallejo, M. A.; Cordova F, T.; Sosa A, M. [Universidad de Guanajuato, Departamento de Ingenieria Fisica, DCI, Loma del Bosque 103, Col. Lomas del Campestre, 37150 Leon, Guanajuato (Mexico); Castruita D, J. P. [Universidad de Guadalajara, Departamento de Ecologia, CUCBA, Las Agujas, 45100 Zapopan, Jalisco (Mexico); Barbosa S, G., E-mail: myrna.sabanero@gmail.com [Universidad de Guanajuato, Departamento de Ciencias Medicas, DCS, 20 de Enero No. 929, Col. Obregon, 37000 Leon, Guanajuato (Mexico)

    2015-10-15

    Acute or chronic exposure to ionizing radiation is a factor that may be hazardous to health. It has been reported that exposure to low doses of radiation (less than 50 mSv / year) and subsequently exposure to high doses have greater effects in people. However, it is unknown molecular and biochemical level alteration. This study, analyzes the susceptibility of a biological system (HeLa Atcc CCL-2 human cervix cancer cell line) to ionizing radiation (6 and 60 mSv/ 90). Our evaluate multiple variables such as: total protein profile, mitochondrial metabolic activity (XTT assay), cell viability (Trypan blue exclusion assay), cytoskeleton (actin micro filaments), nuclei (D API), genomic DNA. The results indicate, that cells exposed to ionizing radiation structurally show alterations in nuclear phenotype and aneuploidy, further disruption in the tight junctions and consequently on the distribution of actin micro filaments. Similar alterations were observed in cells treated with a genotoxic agent (200μM H{sub 2}O{sub 2}/1 h). In conclusion, this multi-criteria assessment enables precise comparisons of the effects of radiation between any biological systems. However, it is necessary to determine stress markers for integration of the effects of ionizing radiation. (Author)

  15. Down-regulation of PERK enhances resistance to ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Oommen, Deepu, E-mail: oommen1978@gmail.com; Prise, Kevin M.

    2013-11-08

    Highlights: •PERK enhances the sensitivity of cancer cells to ionizing radiation. •Down-regulation of PERK results in enhanced DNA repair. •Ionizing radiation-induced apoptosis is inhibited in PERK-down regulated cancer cells. -- Abstract: Although, ionizing radiation (IR) has been implicated to cause stress in endoplasmic reticulum (ER), how ER stress signaling and major ER stress sensors modulate cellular response to IR is unclear. Protein kinase RNA-like endoplasmic reticulum kinase (PERK) is an ER transmembrane protein which initiates unfolded protein response (UPR) or ER stress signaling when ER homeostasis is disturbed. Here, we report that down-regulation of PERK resulted in increased clonogenic survival, enhanced DNA repair and reduced apoptosis in irradiated cancer cells. Our study demonstrated that PERK has a role in sensitizing cancer cells to IR.

  16. Ionizing radiations in Italian health care structures

    Energy Technology Data Exchange (ETDEWEB)

    Fizzano, M.R.; Frusteri, L. [Technical Advisory Dept. for Risk Assessment and Prevention, Italian Workers Compensation Authority, Rome (Italy)

    2006-07-01

    The Council of the European Union has completely renewed the framework regarding radiation protection by adopting some directives: Directive 97/43 EURATOM lays down the general principles of the radiation protection of individuals undergoing exposure to ionising radiations related to medical exposures, as a supplement of Directive 96/29 EURATOM laying down the basic safety standards for the protection of the health of workers and the general public against the dangers arising from ionising radiations.The incorporation into Italian legislation of the European Community directives on the improvement of health and safety at work has promoted a vast effort in order to revise the surveillance approach in many facilities, including hospitals. In Italy, safety law is referred to every workplace; anyway the use of ionising radiations is ruled by specific laws. So in the health care structures it is necessary integrating both the laws and this process is often difficult to carry on. The Italian Legislative Decree 230/95, one the main laws that aim to protect workers against ionising radiations, introduced Directive 96/29/EURATOM. This Decree asks that a doctor and a technical expert analyse the workplace and classify area and workers in according to dose of ionising radiation established by law. The Italian Legislative Decree 626/94 asks that risk analysis in general is made by doctor and specialist in risk. So, in case of risk from ionising radiation, all these figures have to cooperate in order to make an evaluation risk document. (N.C.)

  17. 29 CFR 1910.1096 - Ionizing radiation.

    Science.gov (United States)

    2010-07-01

    ... frequent servicing such as lubrication or cleaning. (v) Where several activating devices feed activating...'s program for control of these radiation sources is incompatible with the requirements of this..., provided the State's program for control of these radiation sources is the subject of a currently...

  18. Combustion study with synchrotron radiation single photon ionization technique

    Institute of Scientific and Technical Information of China (English)

    YANG Rui; WANG Jing; HUANG Chaoqun; YANG Bin; WEI Lixia; SHAN Xiaobin; SHENG Liusi; ZHANG Yunwu; QI Fei

    2005-01-01

    Here we report a combustion endstation at National Synchrotron Radiation Laboratory (NSRL) and some primary experimental results. Synchrotron radiation can provide the tunable vacuum ultraviolet (VUV) photon with the high intensity and the good collimation. VUV photoionization is a single-photon ionization process. Combined with molecular-beam mass spectrometry (MBMS), the VUV single-photon ionization can be applied to detect the combustion products, especially the intermediates and free radicals produced from combustion process. This method is proved to be a powerful tool for combustion study, which could be helpful for developing combustion kinetic models and understanding the mechanism of combustion reactions.

  19. The role of ionizing radiation in primordial organic synthesis.

    Science.gov (United States)

    Ponnamperuma, C.; Sweeney, M.

    1971-01-01

    Attempt to reveal how ionizing radiation may have been effective in producing the molecules necessary for life. In examining the sequence of events leading to the appearance of the first organisms the problem is considered in two parts: the formation of the small molecules such as amino acids, purines, pyrimidines, and carbohydrates; and the condensation of these molecules to give rise to polypeptides and polynucleotides. It is concluded that in the accumulation of organic compounds on the early earth ionizing radiation was not only a substantial part of the available energy, but was also an effective form of energy.

  20. Influence of Dust Loading on Atmospheric Ionizing Radiation on Mars

    Science.gov (United States)

    Norman, Ryan B.; Gronoff, Guillaume; Mertens, Christopher J.

    2014-01-01

    Measuring the radiation environment at the surface of Mars is the primary goal of the Radiation Assessment Detector on the NASA Mars Science Laboratory's Curiosity rover. One of the conditions that Curiosity will likely encounter is a dust storm. The objective of this paper is to compute the cosmic ray ionization in different conditions, including dust storms, as these various conditions are likely to be encountered by Curiosity at some point. In the present work, the Nowcast of Atmospheric Ionizing Radiation for Aviation Safety model, recently modified for Mars, was used along with the Badhwar & O'Neill 2010 galactic cosmic ray model. In addition to galactic cosmic rays, five different solar energetic particle event spectra were considered. For all input radiation environments, radiation dose throughout the atmosphere and at the surface was investigated as a function of atmospheric dust loading. It is demonstrated that for galactic cosmic rays, the ionization depends strongly on the atmosphere profile. Moreover, it is shown that solar energetic particle events strongly increase the ionization throughout the atmosphere, including ground level, and can account for the radio blackout conditions observed by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument on the Mars Express spacecraft. These results demonstrate that the cosmic rays' influence on the Martian surface chemistry is strongly dependent on solar and atmospheric conditions that should be taken into account for future studies.

  1. The oncogenic action of ionizing radiation on rat skin

    Energy Technology Data Exchange (ETDEWEB)

    Burns, F.J.

    1991-01-01

    Progress has occurred in several areas corresponding to the specific aims of the proposal: (1) Progression and multiple events in radiation carcinogenesis of rat skin as a function of LET; (2) cell cycle kinetics of irradiated rat epidermis as determined by double labeling and double emulsion autoradiography; (3) oncogene activation detected by in situ hybridization in radiation-induced rat skin tumors; (4) amplification of the c-myc oncogene in radiation-induced rat skin tumors as a function of LET; and (5) transformation of rat skin keratinocytes by ionizing radiation in combination with c-Ki-ras and c-myc oncogenes. 111 refs., 13 figs., 12 tabs.

  2. Scaling of magneto-quantum-radiative hydrodynamic equations: from laser-produced plasmas to astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Cross, J. E.; Gregori, G. [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Reville, B., E-mail: j.e.cross@physics.ox.ac.uk [Centre for Plasma Physics, Queen' s University Belfast, University Road, Belfast BT7 1NN (United Kingdom)

    2014-11-01

    We introduce the equations of magneto-quantum-radiative hydrodynamics. By rewriting them in a dimensionless form, we obtain a set of parameters that describe scale-dependent ratios of characteristic hydrodynamic quantities. We discuss how these dimensionless parameters relate to the scaling between astrophysical observations and laboratory experiments.

  3. Scaling of Magneto-quantum-radiative Hydrodynamic Equations: From Laser-produced Plasmas to Astrophysics

    Science.gov (United States)

    Cross, J. E.; Reville, B.; Gregori, G.

    2014-11-01

    We introduce the equations of magneto-quantum-radiative hydrodynamics. By rewriting them in a dimensionless form, we obtain a set of parameters that describe scale-dependent ratios of characteristic hydrodynamic quantities. We discuss how these dimensionless parameters relate to the scaling between astrophysical observations and laboratory experiments.

  4. Preservation of food by ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Josephson, E.S.; Peterson, M.S.

    1983-01-01

    This study is presented in three volumes. Vol. I: Presents a concise description of the philosophy of radiation, protection for people working with irradiation processes, including problems associated with the design and operation of a large facility and solutions to problems encountered. Radiation dosimetry and radiolytic effects in foods are also presented. Vol. II: Effects of radiation on bacteria and viruses are discussed as well as the lethal effect on microorganisms and insects. Also presented are the effects of irradiated food on packaging materials. Vol. III: The effects of radurization on meats, poultry, fish, shellfish, fruits, vegetables, and spices. Also included are the effects of irradiation for the use of shelf-life extension.

  5. Exploration of the Dissociative Recombination following DNA ionization to DNA+ due to ionizing radiation

    Science.gov (United States)

    Strom, Richard A.; Zimmerly, Andrew T.; Andrianarijaona, Vola M.

    2014-05-01

    It is known that ionizing radiation generates low-energy secondary electrons, which may interact with the surrounding area, including biomolecules, such as triggering DNA single strand and double strand breaks as demonstrated by Sanche and coworkers (Radiat. Res. 157, 227(2002)). The bio-effects of low-energy electrons are currently a topic of high interest. Most of the studies are dedicated to dissociative electron attachments; however, the area is still mostly unexplored and still not well understood. We are computationally investigating the effect of ionizing radiation on DNA, such as its ionization to DNA+. More specifically, we are exploring the possibility of the dissociative recombination of the temporary DNA+ with one of the low-energy secondary electrons, produced by the ionizing radiation, to be another process of DNA strand breaks. Our preliminary results, which are performed with the binaries of ORCA, will be presented. Authors wish to give special thanks to Pacific Union College Student Senate in Angwin, California, for their financial support.

  6. Effects of ionizing radiation in ginkgo and guarana

    Energy Technology Data Exchange (ETDEWEB)

    Rabelo Soriani, Renata [Departamento de Farmacia, Faculdade de Ciencias Farmaceuticas, Universidade de Sao Paulo, Avenida professor Lineu Prestes, 580-Bloco13, Cidade Universitaria, CEP 05508900 Sao Paulo (Brazil); Satomi, Lucilia Cristina [Departamento de Farmacia, Faculdade de Ciencias Farmaceuticas, Universidade de Sao Paulo, Avenida professor Lineu Prestes, 580-Bloco13, Cidade Universitaria, CEP 05508900 Sao Paulo (Brazil); Pinto, Terezinha de Jesus A. [Departamento de Farmacia, Faculdade de Ciencias Farmaceuticas, Universidade de Sao Paulo, Avenida professor Lineu Prestes, 580-Bloco13, Cidade Universitaria, CEP 05508900 Sao Paulo (Brazil)]. E-mail: tjapinto@usp.br

    2005-07-01

    Raw plant materials normally carry high bioburden due to their origin, offering potential hazards to consumers. The use of decontamination processes is therefore an important step towards the consumer safety and therapeutical efficiency. Several authors have reported the treatment of medicinal herbs with ionizing radiation. This work evaluated the effects of different radiation doses on the microbial burden and chemical constituents of ginkgo (Ginkgo biloba L.) and guarana (Paullinia cupana H.B.K.)

  7. State Register of Sources of Ionizing Radiation and Occupational exposure

    CERN Document Server

    2002-01-01

    One of main tasks of Radiation Protection Centre is to collect, process, systematize, store and provide the data on sources of ionizing radiation and occupational exposures. The number of sources in 2002 is provided and compared with previous year. Distribution of workers according to the type of practice is compared with previous year. Distribution of sealed sources and x-ray machines according their use is presented.

  8. Sensors of absorbed dose of ionizing radiation based on mosfet

    Directory of Open Access Journals (Sweden)

    Perevertaylo V. L.

    2010-10-01

    Full Text Available The requirements to technology and design of p-channel and n-channel MOS transistors with a thick oxide layer designed for use in the capacity of integral dosimeters of absorbed dose of ionizing radiation are defined. The technology of radiation-sensitive MOS transistors with a thick oxide in the p-channel and n-channel version is created.

  9. On the large escape of ionizing radiation from GEHRs

    CERN Document Server

    Castellanos, M; Tenorio-Tagle, G

    2001-01-01

    A thorough analysis of well studied giant HII regions on galactic discs for which we know the ionizing stellar population, the gas metallicity and the Wolf-Rayet population, leads to photoionization models which can only match all observed line intensity ratios ([OIII], [OII], [NII], [SII] and [SIII] with respect to the intensity of H$\\beta$), as well as the H$\\beta$ luminosity and equivalent width if one allows for an important escape of energetic ionizing radiation. For the three regions presented here, the fractions of escaping Lyman continuum photons amount to 10 to 73 % and, in all cases, the larger fraction of escaping photons has energies between 13.6 and 24.4 eV. These escaping photons clearly must have an important impact as a source of ionization of the diffuse ionized gas (DIG) found surrounding many galaxies, as well as of the intergalactic medium (IGM).

  10. Ionizing Radiation Environments and Exposure Risks

    Science.gov (United States)

    Kim, M. H. Y.

    2015-12-01

    Space radiation environments for historically large solar particle events (SPE) and galactic cosmic rays (GCR) are simulated to characterize exposures to radio-sensitive organs for missions to low-Earth orbit (LEO), moon, near-Earth asteroid, and Mars. Primary and secondary particles for SPE and GCR are transported through the respective atmospheres of Earth or Mars, space vehicle, and astronaut's body tissues using NASA's HZETRN/QMSFRG computer code. Space radiation protection methods, which are derived largely from ground-based methods recommended by the National Council on Radiation Protection and Measurements (NCRP) or International Commission on Radiological Protections (ICRP), are built on the principles of risk justification, limitation, and ALARA (as low as reasonably achievable). However, because of the large uncertainties in high charge and energy (HZE) particle radiobiology and the small population of space crews, NASA develops distinct methods to implement a space radiation protection program. For the fatal cancer risks, which have been considered the dominant risk for GCR, the NASA Space Cancer Risk (NSCR) model has been developed from recommendations by NCRP; and undergone external review by the National Research Council (NRC), NCRP, and through peer-review publications. The NSCR model uses GCR environmental models, particle transport codes describing the GCR modification by atomic and nuclear interactions in atmospheric shielding coupled with spacecraft and tissue shielding, and NASA-defined quality factors for solid cancer and leukemia risk estimates for HZE particles. By implementing the NSCR model, the exposure risks from various heliospheric conditions are assessed for the radiation environments for various-class mission types to understand architectures and strategies of human exploration missions and ultimately to contribute to the optimization of radiation safety and well-being of space crewmembers participating in long-term space missions.

  11. Ionizing radiation induces tumor cell lysyl oxidase secretion

    DEFF Research Database (Denmark)

    Shen, Colette J; Sharma, Ashish; Vuong, Dinh-Van;

    2014-01-01

    BACKGROUND: Ionizing radiation (IR) is a mainstay of cancer therapy, but irradiation can at times also lead to stress responses, which counteract IR-induced cytotoxicity. IR also triggers cellular secretion of vascular endothelial growth factor, transforming growth factor beta and matrix...

  12. Role for DNA polymerase beta in response to ionizing radiation.

    NARCIS (Netherlands)

    Vermeulen, C.; Verwijs-Janssen, M.; Cramers, P.; Begg, A.C.; Vens, C.

    2007-01-01

    Evidence for a role of DNA polymerase beta in determining radiosensitivity is conflicting. In vitro assays show an involvement of DNA polymerase beta in single strand break repair and base excision repair of oxidative damages, both products of ionizing radiation. Nevertheless the lack of DNA polymer

  13. Rays Sting: The Acute Cellular Effects of Ionizing Radiation Exposure.

    Science.gov (United States)

    Franco, A; Ciccarelli, M; Sorriento, D; Napolitano, L; Fiordelisi, A; Trimarco, B; Durante, M; Iaccarino, G

    2016-05-01

    High-precision radiation therapy is a clinical approach that uses the targeted delivery of ionizing radiation, and the subsequent formation of reactive oxygen species (ROS) in high proliferative, radiation sensitive cancers. In particular, in thoracic cancer ratdiation treatments, can not avoid a certain amount of cardiac toxicity. Given the low proliferative rate of cardiac myocytes, research has looked at the effect of radiation on endothelial cells and consequent coronary heart disease as the mechanism of ratdiation induced cardiotoxicity. In fact, little is known concerning the direct effect of radiation on mitochondria dynamis in cardiomyocyte. The main effect of ionizing radiation is the production of ROS and recent works have uncovered that they directly participates to pivotal cell function like mitochondrial quality control. In particular ROS seems to act as check point within the cell to promote either mitochondrial biogenesis and survival or mitochondrial damage and apoptosis. Thus, it appears evident that the functional state of the cell, as well as the expression patterns of molecules involved in mitochondrial metabolism may differently modulate mitochondrial fate in response to radiation induced ROS responses. Different molecules have been described to localize to mitochondria and regulate ROS production in response to stress, in particular GRK2. In this review we will discuss the evidences on the cardiac toxicity induced by X ray radiation on cardiomyocytes with emphasis on the role played by mitochondria dynamism.

  14. 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

  15. Scaling of Magneto-Quantum-Radiative Hydrodynamic Equations: From Laser-produced Plasmas to Astrophysics

    CERN Document Server

    Cross, Joseph E

    2014-01-01

    The relevant equations of magneto-quantum-radiative hydrodynamics are introduced and then written in a dimensionless form in order to extract a set of dimensionless parameters that describe scale-dependent ratios of all the characteristic hydrodynamic variables. Under the conditions where such dimensionless number are all large, the equations reduce to the usual ideal magnetohydrodynamics and thus they are scale invariant. We discuss this property with regards to the similarity between astrophysical observations and laboratory experiments. These similarity properties have been successfully exploited in a variety of laboratory experiments where radiative processes can be neglected. On the other hand, when radiation is important, laboratory experiments are much more difficult to scale to the corresponding astrophysical objects. As an example, a recent experiment related to break out shocks in supernova explosions is discussed.

  16. Effects of diagnostic ionizing radiation on pregnancy via TEM

    Energy Technology Data Exchange (ETDEWEB)

    Mohammed, W H; Artoli, A M [Al Neelain University Department of Medical and Biophysics 11121 Khartoum (Sudan)], E-mail: wasilhashim@yahoo.com

    2008-08-15

    In Sudan, X-rays are routinely used at least once for measurements of pelvis during the gestation period, though this is highly prohibited worldwide, except for a few life threatening cases. To demonstrate the effect of diagnostic ionizing radiation on uterus, fetus and neighboring tissues to the ovaries, two independent experiments on pregnant rabbits were conducted. The first experiment was a proof of concept that diagnostic ionizing radiation is hazardous throughout the gestation period. The second experiment was done through Transmission Electron Microscopy (TEM) to elucidate the morphological changes in the ultra structure of samples taken from irradiated pregnant rabbits. This study uses TEM to test the effect of diagnostic radiation of less than 0.6 Gray on the cellular level. Morphological changes have been captured and the images were analyzed to quantify these effects.

  17. Epidemiology and ionizing radiations; Epidemiologie et rayonnements ionisants

    Energy Technology Data Exchange (ETDEWEB)

    Bourguignon, M. [Direction generale de la surete nucleaire et de la radioprotection (DGSNR), 75 - Paris (France); Masse, R. [Academie des technologies, 75 - Paris (France); Slama, R.; Spira, A. [Inserm et Ined U569, Epidemiologie, Demographie et Sciences Sociales: Sante Reproductive, Sexualite et Infection a VIH, 94 - Le Kremlin-Bicetre (France); Timarche, M.; Laurier, D.; Billon, S.; Rogel, A.; Telle Lamberton, M.; Catelinois, O.; Thierry, I. [Institut de Radioprotection et de Surete Nucleaire (IRSN), 92 - Clamart (France); Grosche, B. [Bundesamt fuer Strahlenschutz, Neuherberg (Germany). Inst. fuer Strahlenhygiene; Hall, P. [Karolinska Inst., Dept. d' Epidemiologie Medicale, Stockholm (Sweden); Ron, E. [Institut national du cancer, Div. Epidemiologie du Cancer et Genetique (United States); Vathaire, F. de [INSERM XR 521, Institut Gustave Roussy, 94 - Villejuif (France); Cherie Challine, L.; Donadieu, J.; Pirard, Ph. [Institut de veille sanitaire (InVs), 94415 - Saint-Maurice (France); Bloch, J. [Direction generale de la sante, 75 - Paris (France); Setbon, M. [Centre National de la Recherche Scientifique (CNRS), 75 - Paris (France)

    2004-01-01

    The ionizing radiations have effects on living being. The determinist effects appear since a threshold of absorbed dose of radiation is reached. In return, the stochastic effects of ionizing radiations are these ones whom apparition cannot be described except in terms of probabilities. They are in one hand, cancers and leukemia, on the other hand, lesions of the genome potentially transmissible to the descendants. That is why epidemiology, defined by specialists as the science that studies the frequency and distribution of illness in time and space, the contribution of factors that determine this frequency and this distribution among human populations. This issue gathers and synthesizes the knowledge and examines the difficulties of methodologies. It allows to give its true place to epidemiology. (N.C.)

  18. Cancer risk from low doses of ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Auvinen, A.

    1997-06-01

    The aim of the study was to estimate cancer risk from small doses of ionizing radiation from various sources, including both external and internal exposure. The types of radiation included alpha, gamma, and neutron radiation. A nationwide follow-up study covering the years up to 1992 revealed no significant association between fallout from the Chernobyl accident and incidence of childhood leukemia. An excess of eight cases or more per year could be excluded. However, some indication of an increase was evident in the most heavily affected areas. Furthermore, the risk estimates were in accordance with those reported from Hiroshima and Nagasaki, although the confidence intervals were wide. (282 refs.).

  19. The effect of ionizing radiation on metoprolol.

    Science.gov (United States)

    Ogrodowczyk, Magdalena; Marciniec, Barbara; Czwajda, Aleksandra

    2013-07-01

    The influence of ionising radiation on physico-chemical properties of metoprolol tartrate (MT) in solid phase was studied. The compound was irradiated by radiation produced by a beam of high-energy electrons in an accelerator, in doses from 25 to 400 kGy, and the possible changes in the samples were detected by organoleptic analysis (colour, forms, clarity), chromatographic and spectrometric methods. Already at the standard sterilisation dose of 25 kGy, the presence of free radicals (0.3764 × 10(16) spin/g) and a decrease in the melting point by 1°C were noted. At higher doses of irradiation products of radiolysis appeared (100 kGy) and the colour was changed from white to pale cream (200 kGy). Our observation was that with increasing mass loss of MT after irradiation with 100, 200 and 400 kGy, the concentration of free radicals increased from 1.0330 to 1.6869 × 10(16) spin/g. The radiolytic yield of total radiolysis was 4.54 × 10(7) mol/J for 100 kGy, 7.42 × 10(7) mol/J for 200 kGy and 4.74 × 10(7) mol/J for 400 kGy. No significant changes were observed in the character of FT-IR spectra, but in UV an increase in intensity of the band at the analytical wavelength was noted. As follows from the results MT shows high radiochemical stability for the typical sterilisation doses 25-50 kGy, and will probably be able to be sterilised by radiation in the dose of 25 kGy.

  20. Ionizing radiation in the polyelectrolytes technology

    Science.gov (United States)

    Martin, D.; Dragusin, M.; Radoiu, M.; Moraru, R.; Oproiu, C.; Toma, M.; Ferdes, O.; Jianu, A.; Bestea, V.; Manea, A.

    1999-01-01

    Gamma ray and accelerated electron beam application in the chemistry of polyelectrolytes is presented. The polyelectrolytes preparation is based on radiation induced polymerization of aqueous solutions containing an appropriate mixture of monomers such as acrylamide, acrylic acid, vinyl acetate, diallyldimethylammonium-chloride and certain initiators, complexing agents and chain transfer agents. The effects of absorbed dose, rate of absorbed dose and chemical composition of aqueous solution on the polymerization process are discussed. The results obtained by testing these polyelectrolytes with waste water from food industry are also given.

  1. Influence of ions on relativistic double layers radiation in astrophysical plasmas

    Directory of Open Access Journals (Sweden)

    AM Ahadi

    2009-12-01

    Full Text Available As double layers (DLs are one of the most important acceleration mechanisms in space as well as in laboratory plasmas, they are studied from different points of view. In this paper, the emitted power and energy radiated from charged particles, accelerated in relativistic cosmic DLs are investigated. The effect of the presence of additional ions in a multi-species plasma, as a real example of astrophysical plasma, is also investigated. Considering the acceleration role of DLs, radiations from accelerated charged particles could be seen as a loss mechanism. These radiations are influenced directly by the additional ion species as well as their relative densities.

  2. Interactive visual intervention planning in particle accelerator environments with ionizing radiation

    CERN Document Server

    Fabry, Thomas

    Radiation is omnipresent. It has many interesting applications: in medicine, where it allows curing and diagnosing patients; in communication, where modern communication systems make use of electromagnetic radiation; and in science, where it is used to discover the structure of materials; to name a few. Physically, radiation is a process in which particles or waves travel through any kind of material, usually air. Radiation can be very energetic, in which case it can break the atoms of ordinary matter (ionization). If this is the case, radiation is called ionizing. It is known that ionizing radiation can be far more harmful to living beings than non-ionizing radiation. In this dissertation, we are concerned with ionizing radiation. Naturally occurring ionizing radiation in the form of radioactivity is a most natural phenomenon. Almost everything is radioactive: there is radiation emerging from the soil, it is in the air, and the whole planet is constantly undergoing streams of energetic cosmic radiation. Sinc...

  3. Chromosome Aberrations in Human Lymphocytes Irradiated with Ionizing Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Tae Ho; Kim, Jin Hong; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    The purpose of the present experiment was to provide data on the dose-dependent production of chromosome aberrations such as dicentrics, centric rings, and excess acentrics. Radiation is one of the more dangerous clastogens in the environment. Ionizing radiation causes chromosome breakages and various cytogenetic aberrations in exposed cells. In an investigation into radiation emergencies, it is important to estimate the dose to exposed persons for several reasons. Physical dosimeters (e. g., film badges) may misrepresent the actual radiation dose and may not be available in a radiological accident or terrorism incident. Biological dosimetry is suitable for estimating the radiation dose during such accidents. The dicentric chromosome assay is very sensitive and a reliable bio-indicator in cases of accidental overexposure.

  4. Gaseous Radiochemical Method for Registration of Ionizing Radiation and Its Possible Applications in Science and Industry

    CERN Document Server

    Lebedev, S G

    2005-01-01

    This work presents a new possibility of registration of ionizing radiation by the flowing gaseous radiochemical method (FGRM). The specified method uses the property of some solid crystalline lattice materials for a free emission of radioactive isotopes of inert gas atoms formed as a result of nuclear reactions. Generated in an ampoule of the detector, the radioactive inert gases are transported by a gas-carrier into the proportional gas counter of the flowing type, where the decay rate of the radioactive gas species is measured. This quantity is unequivocally related to the flux of particles (neutrons, protons, light and heavy ions) at the location of the ampoule. The method was used to monitor the neutron flux of the pulsed neutron target "RADEX" driven by the linear proton accelerator of INR RAS. Further progress of the FGRM may give rise to possible applications in nuclear physics, astrophysics and medicine, in the nondestructive control of fissionable materials, diagnostics of thermonuclear plasma, monit...

  5. Research on Dependable Ionizing Radiation Protection based on Model i*

    Directory of Open Access Journals (Sweden)

    Tan Hai

    2013-07-01

    Full Text Available The software’s unreliability mostly attributes to an erroneous analysis on the requirements done at the beginning. In this paper, we apply the tool of i* frame requirement modeling and build early requirement model against ionizing radiation. After finding out possible risks and corresponding solutions during the process of modeling analysis, we propose reasoning models against ionizing radiation. The radiation protection system  with  the  above models  can  figure out  the  purpose  of agents  related  to radiant source and provide normal service even when the environment software system is being interfered. It can serve the ecological and economical society with stability and development.  The model is divided into several sections. Section 1 gives the outline of the dependant software. Section 2 illustrates the  i* frame  technology. Section 3, 4 and 5 cover the topic of dependant security requirement analysis, SD&SR model on ionizing radiation respectively. Section 6 gives the conclusion.

  6. Ionizing radiation from Chernobyl affects development of wild carrot plants

    Science.gov (United States)

    Boratyński, Zbyszek; Arias, Javi Miranda; Garcia, Cristina; Mappes, Tapio; Mousseau, Timothy A.; Møller, Anders P.; Pajares, Antonio Jesús Muñoz; Piwczyński, Marcin; Tukalenko, Eugene

    2016-12-01

    Radioactivity released from disasters like Chernobyl and Fukushima is a global hazard and a threat to exposed biota. To minimize the deleterious effects of stressors organisms adopt various strategies. Plants, for example, may delay germination or stay dormant during stressful periods. However, an intense stress may halt germination or heavily affect various developmental stages and select for life history changes. Here, we test for the consequence of exposure to ionizing radiation on plant development. We conducted a common garden experiment in an uncontaminated greenhouse using 660 seeds originating from 33 wild carrots (Daucus carota) collected near the Chernobyl nuclear power plant. These maternal plants had been exposed to radiation levels that varied by three orders of magnitude. We found strong negative effects of elevated radiation on the timing and rates of seed germination. In addition, later stages of development and the timing of emergence of consecutive leaves were delayed by exposure to radiation. We hypothesize that low quality of resources stored in seeds, damaged DNA, or both, delayed development and halted germination of seeds from plants exposed to elevated levels of ionizing radiation. We propose that high levels of spatial heterogeneity in background radiation may hamper adaptive life history responses.

  7. New Scientific Pearl about Biologic Effect of Ionizing Radiation

    Directory of Open Access Journals (Sweden)

    S. A. Alamdaran

    2008-01-01

    Full Text Available Soon after the discovery of X-ray by Rontgen in 1895, it became evident that radiation can cause some somatic damage to tissues. The hazards of X-ray exposure were clearly known when many large hospitals had radiology departments. The greatest increased in knowledge about X-ray risks had accrued from the dropping of the two atomic bombs in Japan in 1945 and some other atomic accident. For example, among the Japanese bomb survivors from Hiroshima and Nagasaki, there have been about 400 extra cancer deaths. These were the origin of radiology personnel and people fear from radiation exposure and resistant in against simple X-ray exam (radiophobia. However, new scientific data on the effects radiation on survivors, especially about biologic effect of ionizing rays, background radiation exposure, amount of endogenous radiation, hormosis phenomenon and comparison radiation risk with other risk over lifetime are still being continuously revised and risk estimates updated. Fundamentally, this risk is much"nlower than whatever already estimated and it is insignificant in diagnostic domain. Better perception of physician from these instances help to prevent of false radiophobia and to make proper use of diagnostic and therapeutic advantages of ionizing beam.

  8. Perspectives on gravity-induced radiative processes in astrophysics

    CERN Document Server

    Papini, Giorgio

    2015-01-01

    Single-vertex Feynman diagrams represent the dominant contribution to physical processes, but are frequently forbidden kinematically. This is changed when the particles involved propagate in a gravitational background and acquire an effective mass. Procedures are introduced that allow the calculation of lowest order diagrams, their corresponding transition probabilities, emission powers and spectra to all orders in the metric deviation, for particles of any spin propagating in gravitational fields described by any metric. Physical properties of the "space-time medium" are also discussed. It is shown in particular that a small dissipation term in the particle wave equations can trigger a strong back-reaction that introduces resonances in the radiative process and affects the resulting gravitational background.

  9. Resonance Raman Spectroscopy of Free Radicals Produced by Ionizing Radiation

    DEFF Research Database (Denmark)

    Wilbrandt, Robert Walter

    1984-01-01

    Applications of time-resolved resonance Raman spectroscopy to the study of short-lived free radicals produced by ionizing radiation are briefly reviewed. Potential advantages and limitations of this technique are discussed in the light of given examples. The reduction of p-nitrobenzylchloride and......Applications of time-resolved resonance Raman spectroscopy to the study of short-lived free radicals produced by ionizing radiation are briefly reviewed. Potential advantages and limitations of this technique are discussed in the light of given examples. The reduction of p......-nitrobenzylchloride and subsequent formation of the p-nitrobenzyl radical and the reaction of p-nitrotoluene with O– are studied by resonance Raman and optical absorption spectroscopy....

  10. The Spanish National Reference Database for Ionizing Radiations (BANDRRI)

    Energy Technology Data Exchange (ETDEWEB)

    Los Arcos, J.M. E-mail: arcos@ciemat.es; Bailador, A.; Gonzalez, A.; Gonzalez, C.; Gorostiza, C.; Ortiz, F.; Sanchez, E.; Shaw, M.; Williart, A

    2000-03-01

    The Spanish National Reference Database for Ionizing Radiations (BANDRRI) is being implemented by a research team in the frame of a joint project between CIEMAT (Unidad de Metrologia de Radiaciones Ionizantes and Direccion de Informatica) and the Universidad Nacional de Educacion a Distancia (UNED, Departamento de Mecanica y Departamento de Fisica de Materiales). This paper presents the main objectives of BANDRRI, its dynamic and relational data base structure, interactive Web accessibility and its main radionuclide-related contents at this moment.

  11. The non ionizing radiations; Les rayonnements non ionisants

    Energy Technology Data Exchange (ETDEWEB)

    Vecchia, P. [Institut National de la Sante, Lab. de Physique, Rome (Italy); Souques, M. [Electricite de France (EDF), Service des Etudes Medicales, 75 - Paris (France); Lambrozo, J. [EDF/GDF, Service des Etudes Medicales, 75 - Paris (France)] [and others

    2003-07-01

    The biological effects of non ionizing radiations are studied in this part. The magnetic fields and the cardiac implants, melatonin secretion among the electricians exposed to magnetic fields of 50 hz, the effects of electromagnetic fields in professional medium, evaluation of the effect of an exposure to a signal of a mobile phone (GSM 900) on the skin are the different subjects discussed. (N.C.)

  12. Consultative committee on ionizing radiation: Impact on radionuclide metrology.

    Science.gov (United States)

    Karam, L R; Ratel, G

    2016-03-01

    In response to the CIPM MRA, and to improve radioactivity measurements in the face of advancing technologies, the CIPM's consultative committee on ionizing radiation developed a strategic approach to the realization and validation of measurement traceability for radionuclide metrology. As a consequence, measurement institutions throughout the world have devoted no small effort to establish radionuclide metrology capabilities, supported by active quality management systems and validated through prioritized participation in international comparisons, providing a varied stakeholder community with measurement confidence.

  13. Comparisons organized by Ionizing Radiation Metrology Laboratory of FTMC, Lithuania.

    Science.gov (United States)

    Gudelis, A; Gorina, I

    2016-03-01

    The newly established Ionizing Radiation Metrology Laboratory of the National Metrology Institute (FTMC) in Lithuania organized four comparisons in the field of low-level radioactivity measurements in water. For gamma-ray emitters, the activity concentration in the samples was in the range 1-25Bq/kg, while for tritium it was around 2Bq/g. The assigned values of all comparisons were traceable to the primary standards of the Czech Metrology Institute (CMI).

  14. The Spanish National Reference Database for Ionizing Radiations (BANDRRI)

    Science.gov (United States)

    Los Arcos JM; Bailador; Gonzalez; Gonzalez; Gorostiza; Ortiz; Sanchez; Shaw; Williart

    2000-03-01

    The Spanish National Reference Database for Ionizing Radiations (BANDRRI) is being implemented by a reasearch team in the frame of a joint project between CIEMAT (Unidad de Metrologia de Radiaciones Ionizantes and Direccion de Informatica) and the Universidad Nacional de Educacion a Distancia (UNED, Departamento de Mecanica y Departamento de Fisica de Materiales). This paper presents the main objectives of BANDRRI, its dynamic and relational data base structure, interactive Web accessibility and its main radionuclide-related contents at this moment.

  15. Ionizing radiation resistant bacteria; Des bacteries resistantes aux rayonnements ionisants

    Energy Technology Data Exchange (ETDEWEB)

    Libert, M. [CEA/Cadarache, Dept. d' Entreposage et de Stockage des Dechets (DESD), 13 - Saint-Paul-lez-Durance (France)

    2000-07-01

    The living being are not equal face to ionizing radiations. The palm of resistance goes to some bacteria. The champion at any category, the Deinococcus radiodurans, tolerates radiations doses whom one thousandth would kill a man. Two reasons to this fact: after irradiation, the DNA replication is stopped in order that the bacteria can use a repair process called multiple recombination. It cuts intact pieces of a injured chromosome and recombines them with other intact pieces, reconstituting a functional chromosome. It has also an ability to endure the extended action of oxygen, large source of damages for DNA. (N.C.)

  16. Characterization of a CT ionization chamber for radiation field mapping.

    Science.gov (United States)

    Perini, Ana P; Neves, Lucio P; Vivolo, Vitor; Xavier, Marcos; Khoury, Helen J; Caldas, Linda V E

    2012-07-01

    A pencil-type ionization chamber, developed at Instituto de Pesquisas Energéticas e Nucleares (IPEN), was characterized with the objective to verify the possibility of its application in radiation field mapping procedures. The characterization tests were evaluated, and the results were satisfactory. The results obtained for the X radiation field mapping with the homemade chamber were compared with those of a PTW Farmer-type chamber (TN 30011-1). The maximum difference observed in this comparison was only 1.25%, showing good agreement.

  17. Application of ionizing radiation processing in biomedical engineering and microelectronics

    Energy Technology Data Exchange (ETDEWEB)

    Hongfej, H.; Jilan, W.

    1988-01-01

    The applied radiation chemistry has made great contributions to the development of polymeric industrial materials by the characteristics reaction means such as crosslinking, graft copolymerization and low-temperature or solid-phase polymerization, and become a important field on peaceful use of atomic energy. A brief review on the applications of ionizing radiation processing in biomedical engineering and microelectronics is presented. The examples of this technique were the studies on biocompatible and biofunctional polymers for medical use and on resists of lithography in microelectronics.

  18. Ionizing radiation effects on food vitamins: a review

    Energy Technology Data Exchange (ETDEWEB)

    Dionisio, Ana Paula, E-mail: annadionisio@yahoo.com.b [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Faculdade de Engenharia de Alimentos. Dept. de Ciencia de Alimentos; Gomes, Renata Takassugui; Oetterer, Marilia [Universidade de Sao Paulo (USP), Piracicaba, SP (Brazil). Escola Superior de Agricultura Luiz de Queiroz. Dept. de Agroindustria, Alimentos e Nutricao

    2009-09-15

    Ionizing radiation has been widely used in industrial processes, especially in the sterilization of medicines, pharmaceuticals, cosmetic products, and in food processing. Similar to other techniques of food processing, irradiation can induce certain alterations that can modify both the chemical composition and the nutritional value of foods. These changes depend on the food composition, the irradiation dose and factors such as temperature and presence or absence of oxygen in the irradiating environment. The sensitivity of vitamins to radiation is unpredictable and food vitamin losses during the irradiation are often substantial. The aim of this study was to discuss retention or loss of vitamins in several food products submitted to an irradiation process. (author)

  19. Characterization of a CT ionization chamber for radiation field mapping

    Energy Technology Data Exchange (ETDEWEB)

    Perini, Ana P., E-mail: aperini@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN), Comissao Nacional de Energia Nuclear, Av. Prof. Lineu Prestes 2242, 05508-000, Sao Paulo, SP (Brazil); Neves, Lucio P., E-mail: lpneves@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN), Comissao Nacional de Energia Nuclear, Av. Prof. Lineu Prestes 2242, 05508-000, Sao Paulo, SP (Brazil); Vivolo, Vitor, E-mail: vivolo@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN), Comissao Nacional de Energia Nuclear, Av. Prof. Lineu Prestes 2242, 05508-000, Sao Paulo, SP (Brazil); Xavier, Marcos, E-mail: mxavier@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN), Comissao Nacional de Energia Nuclear, Av. Prof. Lineu Prestes 2242, 05508-000, Sao Paulo, SP (Brazil); Khoury, Helen J., E-mail: hjkhoury@gmail.com [Universidade Federal de Pernambuco, Departamento de Energia Nuclear, Av. Prof. Luiz Freire 1000, 50740-540, Recife, PE (Brazil); Caldas, Linda V.E., E-mail: lcaldas@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN), Comissao Nacional de Energia Nuclear, Av. Prof. Lineu Prestes 2242, 05508-000, Sao Paulo, SP (Brazil)

    2012-07-15

    A pencil-type ionization chamber, developed at Instituto de Pesquisas Energeticas e Nucleares (IPEN), was characterized with the objective to verify the possibility of its application in radiation field mapping procedures. The characterization tests were evaluated, and the results were satisfactory. The results obtained for the X radiation field mapping with the homemade chamber were compared with those of a PTW Farmer-type chamber (TN 30011-1). The maximum difference observed in this comparison was only 1.25%, showing good agreement. - Highlights: Black-Right-Pointing-Pointer A new ionization chamber was made and tested for radiation field mapping. Black-Right-Pointing-Pointer This ionization chamber was made using only accessible low cost materials. Black-Right-Pointing-Pointer The operational tests were made and the results were within the recommended limits. Black-Right-Pointing-Pointer The field map was compared with a commercial chamber presenting a 1.25% difference. Black-Right-Pointing-Pointer Our chamber presents potential for assurance reliability in calibration procedures.

  20. Supported transition metal nanomaterials: Nanocomposites synthesized by ionizing radiation

    Science.gov (United States)

    Clifford, D. M.; Castano, C. E.; Rojas, J. V.

    2017-03-01

    Nanostructures decorated with transition metal nanoparticles using ionizing radiation as a synthesis method in aqueous solutions represents a clean alternative to existing physical, chemical and physicochemical methods. Gamma irradiation of aqueous solutions generates free radicals, both oxidizing and reducing species, all distributed homogeneously. The presence of oxidant scavengers in situ during irradiation generates a highly reductive environment favoring the reduction of the metal precursors promoting seed formation and nanoparticle growth. Particle growth is controlled by addition of surfactants, polymers or various substrates, otherwise referred to as supports, which enhance the formation of well dispersed nanoparticles. Furthermore, the combination of nanoparticles with supports can offer desirable synergisms not solely presented by the substrate or nanoparticles. Thus, supported nanoparticles offer a huge diversity of applications. Among the ionizing radiation methods to synthesize nanomaterials and modify their characteristics, gamma irradiation is of growing interest and it has shown tremendous potential in morphological control and distribution of particle size by judiciously varying parameters including absorbed dose, dose rate, concentration of metal precursor, and stabilizing agents. In this work, major advances on the synthesis of supported nanoparticles through gamma irradiation are reviewed as well as the opportunities to develop and exploit new composites using gamma-rays and other accessible ionizing radiation sources such as X-rays.

  1. Health risk assessment of jobs involving ionizing radiation sources

    Directory of Open Access Journals (Sweden)

    Spasojević-Tišma Vera D.

    2011-01-01

    Full Text Available The study included 75 subjects exposed to low doses of external ionizing radiation and 25 subjects from the control group, all male. The first group (A consisted of 25 subjects employed in the production of technetium, with an average job experience of 15 years. The second group (B consisted of 25 subjects exposed to ionizing radiation from enclosed sources, working in jobs involving the control of X-ray devices and americium smoke detectors, their average work experience being 18.5 years. The third group (C consisted of 25 subjects involved in the decontamination of the terrain at Borovac from radioactive rounds with depleted uranium left over after the NATO bombing of Serbia in 1999, their average job experience being 18.5 years. The control group (K consisted of 25 subjects who have not been in contact with sources of ionizing radiation and who hold administrative positions. Frequencies of chromosome aberrations were determined in lymphocytes of peripheral blood and compared to the control group. The average annual absorbed dose determined by thermoluminescent dosimeters for all three groups did not exceed 2 mSv. In the present study, the largest number of observed changes are acentric fragments and chromosome breaks. The highest occupational risk appears to involve subjects working in manufacturing of the radio-isotope technetium.

  2. Effects of ionizing radiation on modern ion exchange materials

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, S.F.; Pillay, K.K.S.

    1993-10-01

    We review published studies of the effects of ionizing radiation on ion exchange materials, emphasizing those published in recent years. A brief overview is followed by a more detailed examination of recent developments. Our review includes styrene/divinylbenzene copolymers with cation-exchange or anion-exchange functional groups, polyvinylpyridine anion exchangers, chelating resins, multifunctional resins, and inorganic exchangers. In general, strong-acid cation exchange resins are more resistant to radiation than are strong-base anion exchange resins, and polyvinylpyridine resins are more resistant than polystyrene resins. Cross-linkage, salt form, moisture content, and the surrounding medium all affect the radiation stability of a specific exchanger. Inorganic exchangers usually, but not always, exhibit high radiation resistance. Liquid ion exchangers, which have been used so extensively in nuclear processing applications, also are included.

  3. NIF laboratory astrophysics simulations investigating the effects of a radiative shock on hydrodynamic instabilities

    Science.gov (United States)

    Angulo, A. A.; Kuranz, C. C.; Drake, R. P.; Huntington, C. M.; Park, H.-S.; Remington, B. A.; Kalantar, D.; MacLaren, S.; Raman, K.; Miles, A.; Trantham, Matthew; Kline, J. L.; Flippo, K.; Doss, F. W.; Shvarts, D.

    2016-10-01

    This poster will describe simulations based on results from ongoing laboratory astrophysics experiments at the National Ignition Facility (NIF) relevant to the effects of radiative shock on hydrodynamically unstable surfaces. The experiments performed on NIF uniquely provide the necessary conditions required to emulate radiative shock that occurs in astrophysical systems. The core-collapse explosions of red supergiant stars is such an example wherein the interaction between the supernova ejecta and the circumstellar medium creates a region susceptible to Rayleigh-Taylor (R-T) instabilities. Radiative and nonradiative experiments were performed to show that R-T growth should be reduced by the effects of the radiative shocks that occur during this core-collapse. Simulations were performed using the radiation hydrodynamics code Hyades using the experimental conditions to find the mean interface acceleration of the instability and then further analyzed in the buoyancy drag model to observe how the material expansion contributes to the mix-layer growth. This work is funded by the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas under Grant Number DE-FG52-09NA29548.

  4. Battery-powered pulsed high density inductively coupled plasma source for pre-ionization in laboratory astrophysics experiments.

    Science.gov (United States)

    Chaplin, Vernon H; Bellan, Paul M

    2015-07-01

    An electrically floating radiofrequency (RF) pre-ionization plasma source has been developed to enable neutral gas breakdown at lower pressures and to access new experimental regimes in the Caltech laboratory astrophysics experiments. The source uses a customized 13.56 MHz class D RF power amplifier that is powered by AA batteries, allowing it to safely float at 3-6 kV with the electrodes of the high voltage pulsed power experiments. The amplifier, which is capable of 3 kW output power in pulsed (<1 ms) operation, couples electrical energy to the plasma through an antenna external to the 1.1 cm radius discharge tube. By comparing the predictions of a global equilibrium discharge model with the measured scalings of plasma density with RF power input and axial magnetic field strength, we demonstrate that inductive coupling (rather than capacitive coupling or wave damping) is the dominant energy transfer mechanism. Peak ion densities exceeding 5 × 10(19) m(-3) in argon gas at 30 mTorr have been achieved with and without a background field. Installation of the pre-ionization source on a magnetohydrodynamically driven jet experiment reduced the breakdown time and jitter and allowed for the creation of hotter, faster argon plasma jets than was previously possible.

  5. Use of Ionizing Radiation Technology for Treating Municipal Wastewater

    Directory of Open Access Journals (Sweden)

    Firas R. Al-Khalidy

    2006-12-01

    Full Text Available In big cities, the cost of treating wastewater is increasing with more stringent environmental requirements. Ionizing radiation technology for treating municipal wastewater may be an alternative to reduce treatment costs. In this paper, laboratory tests were carried out using different doses of radiation to treat wastewater samples collected from the AL-Rustamia wastewater treatment plant in Baghdad city. According to the results, irradiation by gamma radiation with a dose ranging from 100 to 500 krad was efficient in reducing some of the physical contaminants. The organic contaminants were degraded and reduced to about 12% of their original concentrations. Generally, irradiation technology could effectively modify the characteristics of the wastewater to such levels that are compatible with Iraqi disposal standards. The results of the study also showed that, an experimental pilot plant study is required to optimize the cost of wastewater treatment through the use of this technology.

  6. Genomic damage in children accidentally exposed to ionizing radiation

    DEFF Research Database (Denmark)

    Fucic, A; Brunborg, G; Lasan, R

    2007-01-01

    During the last decade, our knowledge of the mechanisms by which children respond to exposures to physical and chemical agents present in the environment, has significantly increased. Results of recent projects and programmes focused on children's health underline a specific vulnerability...... 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...... after the Chernobyl nuclear plant accident in 1986. The present review presents and discusses data collected from papers analyzing genome damage in children environmentally exposed to ionizing radiation. Overall, the evidence from the studies conducted following the Chernobyl accident, nuclear tests...

  7. Comet assay as a procedure for detecting possible genotoxicity induced by non-ionizing radiation

    OpenAIRE

    Zsuzsanna Nemeth

    2015-01-01

    Non-ionizing radiation (NIR) is the term given to radiation in the part of the electromagnetic spectrum that does not have enough energy to ionize atoms or molecules directly. The NIR includes electric and magnetic fields up to 300 GHz, infrared, visible, and ultraviolet radiation (UV). People are exposed to non-ionizing radiation by several man-made sources every day. From highest to lowest energy, this includes for example microwave ovens, cell phones, baby monitors, cordless phones, ga...

  8. The Effects of the Ionizing Radiation Background on Galaxy Evolution

    CERN Document Server

    Hambrick, D Clay; Naab, Thorsten; Johansson, Peter H

    2009-01-01

    We find that the amount and nature of the assumed ionizing background can strongly affect galaxy formation and evolution. Galaxy evolution simulations typically incorporate an ultraviolet background which falls off rapidly above z=3; e.g., that of Haardt & Madau (1996). However, this decline may be too steep to fit the WMAP constraints on electron scattering optical depth or observations of intermediate redshift (z ~ 2-4) Ly-alpha forest transmission. As an alternative, we present simulations of the cosmological formation of individual galaxies with UV backgrounds that decline more slowly at high redshift: both a simple intensity rescaling and the background recently derived by Faucher-Giguere (2009), which softens the spectrum at higher redshifts. We also test an approximation of the X-ray background with a similar z-dependence. We find for the test galaxies that an increase in either the intensity or hardness of ionizing radiation generically pushes star formation towards lower redshifts: although overa...

  9. Final Report for "Verification and Validation of Radiation Hydrodynamics for Astrophysical Applications"

    Energy Technology Data Exchange (ETDEWEB)

    Zingale, M; Howell, L H

    2010-03-17

    The motivation for this work is to gain experience in the methodology of verification and validation (V&V) of astrophysical radiation hydrodynamics codes. In the first period of this work, we focused on building the infrastructure to test a single astrophysical application code, Castro, developed in collaboration between Lawrence Livermore National Laboratory (LLNL) and Lawrence Berkeley Laboratory (LBL). We delivered several hydrodynamic test problems, in the form of coded initial conditions and documentation for verification, routines to perform data analysis, and a generalized regression test suite to allow for continued automated testing. Astrophysical simulation codes aim to model phenomena that elude direct experimentation. Our only direct information about these systems comes from what we observe, and may be transient. Simulation can help further our understanding by allowing virtual experimentation of these systems. However, to have confidence in our simulations requires us to have confidence in the tools we use. Verification and Validation is a process by which we work to build confidence that a simulation code is accurately representing reality. V&V is a multistep process, and is never really complete. Once a single test problem is working as desired (i.e. that problem is verified), one wants to ensure that subsequent code changes do not break that test. At the same time, one must also search for new verification problems that test the code in a new way. It can be rather tedious to manually retest each of the problems, so before going too far with V&V, it is desirable to have an automated test suite. Our project aims to provide these basic tools for astrophysical radiation hydrodynamics codes.

  10. A link between solar events and congenital malformations: Is ionizing radiation enough to explain it?

    CERN Document Server

    Overholt, A C; Atri, D

    2015-01-01

    Cosmic rays are known to cause biological effects directly and through ionizing radiation produced by their secondaries. These effects have been detected in airline crews and other specific cases where members of the population are exposed to above average secondary fluxes. Recent work has found a correlation between solar particle events and congenital malformations. In this work we use the results of computational simulations to approximate the ionizing radiation from such events as well as longer term increases in cosmic ray flux. We find that the amounts of ionizing radiation produced by these events are insufficient to produce congenital malformations under the current paradigm regarding muon ionizing radiation. We believe that further work is needed to determine the correct ionizing radiation contribution of cosmogenic muons. We suggest that more extensive measurements of muon radiation effects may show a larger contribution to ionizing radiation dose than currently assumed.

  11. Desulfurization of petroleum induced by ionization radiation: benzothiophene behavior

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Luana S.; Calvo, Wilson A.P.; Duarte, Celina L., E-mail: lsandrade@ipen.br, E-mail: wapcalvo@ipen.br, E-mail: clduarte@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    Hydrodesulfurization (HDS) is currently the most common method used by refineries; this removes significantly sulfur compounds from petroleum fractions, however, is not highly effective for removing thiophene compounds such as benzothiophene, and generates high costs for the oil industry. Another factor, are the environmental laws, which over the years has become increasingly strict, especially regarding the sulfur content. This compound cause incalculable damage both to the industry and to the environment. Therefore new methods for petroleum desulfurization should be studied in order to minimize the impacts that these compounds cause. In the present study it was used ionizing radiation, a promising method of advanced oxidation in reducing sulfur compounds. The analysis were performed after purge and trap concentration of samples, followed by gas chromatography-mass spectrometry (GC-MS). Then benzothiophene samples with the same concentration from 27 mg.L{sup -1} to 139 mg.L{sup -1} were irradiated with different absorbed doses of radiation ranging from 1 kGy to 20 kGy in gamma irradiator Cobalt-60, Gammacell. These samples were analyzed by the same procedure used for the calibration curve, and the removals of benzothiophene after ionizing radiation treatment were calculated. It was observed that at higher doses there was a greater degradation of this compound and the formation of fragments, such as 1,2-dimethylbenzene and toluene, which may be removed by simple processes. (author)

  12. Mechanism of Interaction between Ionizing Radiation and Chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Kyu; Lee, B. H.; Shin, H. S. (and others)

    2008-03-15

    This research project has been carried out jointly with INP (Poland) to develop technologies for 'Mechanism of Interaction between ionizing radiation and chemicals{sup .} Several biological end-points were assessed in experimental organisms such as higher plants, rats, cell lines and yeast cells to establish proper bioassay techniques. The Tradescantia somatic cell mutation assay was carried out, and immunohistochemistry and hormone assays were done in Fisher 344 rats and cell lines to analyse the combined effect of ionizing radiation with mercury chloride. Using the common regularities of combined actions of two factors, a theoretical model was established, and applied to the thermo radiation action and synergism between two chemicals, as well. The model approach made it possible to predict the condition under which the maximum synergism could be attained. The research results were published in high standard journals and presented in the scientific conferences to verify KAERI's current technology level. The experience of collaboration can be used as a fundamental tool for multinational collaboration, and make the role of improving relationship between Korea and Poland.

  13. Expression of P53 protein after exposure to ionizing radiation

    Science.gov (United States)

    Salazar, A. M.; Salvador, C.; Ruiz-Trejo, C.; Ostrosky, P.; Brandan, M. E.

    2001-10-01

    One of the most important tumor suppressor genes is p53 gene, which is involved in apoptotic cell death, cell differentiation and cell cycle arrest. The expression of p53 gene can be evaluated by determining the presence of P53 protein in cells using Western Blot assay with a chemiluminescent method. This technique has shown variabilities that are due to biological factors. Film developing process can influence the quality of the p53 bands obtained. We irradiated tumor cell lines and human peripheral lymphocytes with 137Cs and 60Co gamma rays to standardize irradiation conditions, to compare ionizing radiation with actinomycin D and to reduce the observed variability of P53 protein induction levels. We found that increasing radiation doses increase P53 protein induction while it decreases viability. We also conclude that ionizing radiation could serve as a positive control for Western Blot analysis of protein P53. In addition, our results show that the developing process may play an important role in the quality of P53 protein bands and data interpretation.

  14. Effect of ionizing radiation on platelet function in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Kalovidouris, A.E.; Papayannis, A.G. (Evangelismos Hospital, Athens (Greece))

    1981-01-01

    The effect of ionizing radiation on platelet function was investigated in vitro. Platelet-rich plasma (300x10/sup 9//l) was irradiated with doses of 1, 4, 10, 20 and 50 Gy. Platelet function tests were performed on both irradiated and control (non-irradiated) platelet samples. The platelet function tests were (1) platelet aggregation by ADP (1, 2, 4 ..mu..mol final concentration), adrenaline and collagen, (2) ADP-release from platelets, (3) clot retraction and (4) platelet factor-3 availability. It was found that roentgen irradiation of platelets in vitro did not affect these platelet function tests.

  15. Determination of the Astrophysical S(E) Factors or Rates for Radiative Capture Reaction with One Nucleon Transfer Reaction%Determination of the Astrophysical S(E) Factors or Rates for Radiative Capture Reaction with One Nucleon Transfer Reaction

    Institute of Scientific and Technical Information of China (English)

    李志宏; 郭冰; 李云居; 苏俊; 李二涛; 白希祥; 王友宝; 曾晟; 王宝祥; 颜胜权; 李志常; 刘建成; 连钢; 金孙均; 刘鑫; 柳卫平

    2012-01-01

    The radiative capture reaction plays an important role in nuclear astrophysics. We have indirectly measured the astrophysical S(E) factors for some proton capture reactions and reaction rates for several neutron capture reactions with one nucleon transfer reactions at HI-13 tandem accelerator in recent years. Some of them are compiled into IAEA EXFOR database and JINA REACLIB project, and used in the network calculations of Big Bang nucleosynthesis and type-I X-ray bursts.

  16. Teratogen effects of ionizing radiations. Effets teratogenes des rayonnements ionisants

    Energy Technology Data Exchange (ETDEWEB)

    Vera, P. (Hopital Beaujon, 92 - Clichy (France)); Gambini, D.J.; Collignon-le-Bouedec, M.A.; Barritault, L. (Hopital Laennec, 75 - Paris (France))

    1994-03-01

    This article treats the problem of teratogenesis of ionizing radiations. If no malformations has been seen before 20*10 [sup -2] Grays and no carcinogen effect before 30*10 [sup -2] Grays, it is reasonable to limit the irradiation of pregnant women. If there is an emergency for mother's life as it is the case in thrombo-embolic pathology, all ways of protection must be used: high voltage, diaphragms, reduction of time exposure, abdomen protection with screens, fast screen-film couples, radioscopy television, limiting number of negatives, make the mother drink after the examination to eliminate the radioactive products. Note that beta radiations are contraindicated and preferentially use, when it is possible, echography, echo doppler or nuclear magnetic resonance.

  17. EPR detection of foods preserved with ionizing radiation

    Science.gov (United States)

    Stachowicz, W.; Burlinska, G.; Michalik, J.

    1998-06-01

    The applicability of the epr technique for the detection of dried vegetables, mushrooms, some spices, flavour additives and some condiments preserved with ionizing radiation is discussed. The epr signals recorded after exposure to gamma rays and to beams of 10 MeV electrons from linac are stable, intense and specific enough as compared with those observed with nonirradiated samples and could be used for the detection of irradiation. However, stability of radiation induced epr signals produced in these foods depends on storage condition. No differences in shapes (spectral parameters) and intensities of the epr spectra recorded with samples exposed to the same doses of gamma rays ( 60Co) and 10 MeV electrons were observed

  18. Molecular targets in cellular response to ionizing radiation and implications in space radiation protection

    Energy Technology Data Exchange (ETDEWEB)

    Belli, M.; Tabocchini, M.A. [Istituto Superiore di Sanita, Rome (Italy). Physics Lab.; Sapora, O. [Istituto Superiore di Sanita, Rome (Italy). Comparative Toxicology Lab.

    2002-12-01

    DNA repair systems and cell cycle checkpoints closely co-operate in the attempt of maintaining the genomic integrity of cells damaged by ionizing radiation. DNA double-strand breaks (DSB) are considered as the most biologically important radiation-induced damage. Their spatial distribution and association with other types of damage depend on radiation quality. It is believed these features affect damage reparability, thus explaining the higher efficiency for cellular effects of densely ionizing radiation with respect to {gamma}-rays. DSB repair systems identified in mammalian cells are homologous recombination (HR), single-strand annealing (SSA) and non-homologous end-joining (NHEJ). Some enzymes may participate in more than one of these repair systems. DNA damage also triggers biochemical signals activating checkpoints responsible for delay in cell cycle progression that allows more time for repair. Those at G1/S and S phases prevent replication of damaged DNA and those at G2/M phase prevent segregation of changed chromosomes. Individuals with lack or alterations of genes involved in DNA DSB repair and cell cycle checkpoints exhibit syndromes characterized by genome instability and predisposition to cancer. Information reviewed in this paper on the basic mechanisms of cellular response to ionizing radiation indicates their importance for a number of issues relevant to protection of astronauts from space radiation. (author)

  19. Ionizing radiation and a wood-based biorefinery

    Science.gov (United States)

    Driscoll, Mark S.; Stipanovic, Arthur J.; Cheng, Kun; Barber, Vincent A.; Manning, Mellony; Smith, Jennifer L.; Sundar, Smith

    2014-01-01

    Woody biomass is widely available around the world. Cellulose is the major structural component of woody biomass and is the most abundant polymer synthesized by nature, with hemicellulose and lignin being second and third. Despite this great abundance, woody biomass has seen limited application outside of the paper and lumber industries. Its use as a feedstock for fuels and chemicals has been limited because of its highly crystalline structure, inaccessible morphology, and limited solubility (recalcitrance). Any economic use of woody biomass for the production of fuels and chemicals requires a "pretreatment" process to enhance the accessibility of the biomass to enzymes and/or chemical reagents. Electron beams (EB), X-rays, and gamma rays produce ions in a material which can then initiate chemical reactions and cleavage of chemical bonds. Such ionizing radiation predominantly scissions and degrades or depolymerizes both cellulose and hemicelluloses, less is known about its effects on lignin. This paper discusses how ionizing radiation can be used to make a wood-based biorefinery more environmentally friendly and profitable for its operators.

  20. Large single-crystal diamond substrates for ionizing radiation detection

    Energy Technology Data Exchange (ETDEWEB)

    Girolami, Marco; Bellucci, Alessandro; Calvani, Paolo; Trucchi, Daniele M. [Istituto di Struttura della Materia (ISM), Consiglio Nazionale delle Ricerche (CNR), Sede Secondaria di Montelibretti, Monterotondo Stazione, Roma (Italy)

    2016-10-15

    The need for large active volume detectors for ionizing radiations and particles, with both large area and thickness, is becoming more and more compelling in a wide range of applications, spanning from X-ray dosimetry to neutron spectroscopy. Recently, 8.0 x 8.0 mm{sup 2} wide and 1.2 mm thick single-crystal diamond plates have been put on the market, representing a first step to the fabrication of large area monolithic diamond detectors with optimized charge transport properties, obtainable up to now only with smaller samples. The more-than-double thickness, if compared to standard plates (typically 500 μm thick), demonstrated to be effective in improving the detector response to highly penetrating ionizing radiations, such as γ-rays. Here we report on the first measurements performed on large active volume single-crystal diamond plates, both in the dark and under irradiation with optical wavelengths (190-1100 nm), X-rays, and radioactive γ-emitting sources ({sup 57}Co and {sup 22}Na). (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Review of using gallium nitride for ionizing radiation detection

    Science.gov (United States)

    Wang, Jinghui; Mulligan, Padhraic; Brillson, Leonard; Cao, Lei R.

    2015-09-01

    With the largest band gap energy of all commercial semiconductors, GaN has found wide application in the making of optoelectronic devices. It has also been used for photodetection such as solar blind imaging as well as ultraviolet and even X-ray detection. Unsurprisingly, the appreciable advantages of GaN over Si, amorphous silicon (a-Si:H), SiC, amorphous SiC (a-SiC), and GaAs, particularly for its radiation hardness, have drawn prompt attention from the physics, astronomy, and nuclear science and engineering communities alike, where semiconductors have traditionally been used for nuclear particle detection. Several investigations have established the usefulness of GaN for alpha detection, suggesting that when properly doped or coated with neutron sensitive materials, GaN could be turned into a neutron detection device. Work in this area is still early in its development, but GaN-based devices have already been shown to detect alpha particles, ultraviolet light, X-rays, electrons, and neutrons. Furthermore, the nuclear reaction presented by 14N(n,p)14C and various other threshold reactions indicates that GaN is intrinsically sensitive to neutrons. This review summarizes the state-of-the-art development of GaN detectors for detecting directly and indirectly ionizing radiation. Particular emphasis is given to GaN's radiation hardness under high-radiation fields.

  2. Review of using gallium nitride for ionizing radiation detection

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jinghui [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Department of Radiology, Stanford University, Stanford, California 94305 (United States); Mulligan, Padhraic; Cao, Lei R., E-mail: cao.152@osu.edu [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Brillson, Leonard [Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States)

    2015-09-15

    With the largest band gap energy of all commercial semiconductors, GaN has found wide application in the making of optoelectronic devices. It has also been used for photodetection such as solar blind imaging as well as ultraviolet and even X-ray detection. Unsurprisingly, the appreciable advantages of GaN over Si, amorphous silicon (a-Si:H), SiC, amorphous SiC (a-SiC), and GaAs, particularly for its radiation hardness, have drawn prompt attention from the physics, astronomy, and nuclear science and engineering communities alike, where semiconductors have traditionally been used for nuclear particle detection. Several investigations have established the usefulness of GaN for alpha detection, suggesting that when properly doped or coated with neutron sensitive materials, GaN could be turned into a neutron detection device. Work in this area is still early in its development, but GaN-based devices have already been shown to detect alpha particles, ultraviolet light, X-rays, electrons, and neutrons. Furthermore, the nuclear reaction presented by {sup 14}N(n,p){sup 14}C and various other threshold reactions indicates that GaN is intrinsically sensitive to neutrons. This review summarizes the state-of-the-art development of GaN detectors for detecting directly and indirectly ionizing radiation. Particular emphasis is given to GaN's radiation hardness under high-radiation fields.

  3. Annual Report 2006 for Hydrodynamics and Radiation Hydrodynamics with Astrophysical Applications

    Energy Technology Data Exchange (ETDEWEB)

    R. Paul Drake

    2007-04-05

    We report the ongoing work of our group in hydrodynamics and radiation hydrodynamics with astrophysical applications. During the period of the existing grant, we have carried out two types of experiments at the Omega laser. One set of experiments has studied radiatively collapsing shocks, obtaining data using a backlit pinhole with a 100 ps backlighter and beginning to develop the ability to look into the shock tube with optical or x-ray diagnostics. Other experiments have studied the deeply nonlinear development of the Rayleigh-Taylor (RT) instability from complex initial conditions, using dual-axis radiographic data with backlit pinholes and ungated detectors to complete the data set for a Ph.D. student. We lead a team that is developing a proposal for experiments at the National Ignition Facility and are involved in experiments at NIKE and LIL. All these experiments have applications to astrophysics, discussed in the corresponding papers. We assemble the targets for the experiments at Michigan, where we also prepare many of the simple components. We also have several projects underway in our laboratory involving our x-ray source. The above activities, in addition to a variety of data analysis and design projects, provide good experience for graduate and undergraduates students. In the process of doing this research we have built a research group that uses such work to train junior scientists.

  4. Hawking radiation from astrophysical black holes to analogous systems in lab

    CERN Document Server

    Belgiorno, Francesco D

    2017-01-01

    The aim of this book is to provide the reader with a guide to Hawking radiation through a dual approach to the problem. In the first part of the book, we summarize some basic knowledge about black holes and quantum field theory in curved spacetime. In the second part, we present a survey of methods for deriving and studying Hawking radiation from astrophysical black holes, from the original calculation by S W Hawking to the most recent contributions involving gravitational anomalies and tunneling. In the third part, we introduce analogue gravity models, with particular attention to dielectric black hole systems, to which the studies of the present authors are devoted. The mutual interchange of knowledge between the aforementioned parts is addressed to render a more comprehensive picture of this very fascinating quantum phenomenon associated with black holes.

  5. The oncogenic action of ionizing radiation on rat skin

    Energy Technology Data Exchange (ETDEWEB)

    Burns, F.J.; Garte, S.J.

    1992-01-01

    The multistage theory of carcinogenesis specifies that cells progress to cancer through a series of discrete, irreversible genetic alterations, but data on radiation-induced cancer incidence in rat skin suggests that an intermediate repairable alteration may occur. Data are presented on cancer induction in rat skin exposed to an electron beam (LET=0.34 keV/[mu]), a neon ion beam (LET=45) or an argon ion beam (LET=125). The rats were observed for tumors at least 78 weeks with squamous and basal cell carcinomas observed. The total cancer yield was fitted by the quadratic equation, and the equation parameters were estimated by linear regression for each type of radiation. Analysis of the DNA from the electron-induced carcinomas indicated that K-ras and/or c-myc oncogenes were activated. In situ hybridization indicated that the cancers contain subpopulations of cells with differing amounts of c-myc and H-ras amplification. The results are consistent with the idea that ionizing radiation produces stable, carcinogenically relevant lesions via 2 repairable events at low LET and via a non-repairable linked event pathway at high LET; either pathway may advance the cell by 1 stage. The proliferative response of rat epidermis following exposure to ionizing radiation was quantified by injection of [sup 14]C-thymidine. The return of these cells to S-phase a second time was detected by a second label ([sup 3]H). When the labeled cells were in G1-phase, the dorsal skin was irradiated with X-rays. All labeling indices were determined. The [sup 14]C labeling index was constant and unaffected by the radiation. The proportion of all cells entering S-phase averaged 3.5% at 18 hr and increased after 44, 52 and 75 hr to average levels of 11.8%, 5. 3%, and 6.6% at 0, 10 and 25 Gy respectively. The proportion of S-phase cells labeled with [sup 14]C increased after 42 hr and remained relatively constant thereafter.

  6. Ionizing radiation risks to satellite power systems (SPS) workers

    Energy Technology Data Exchange (ETDEWEB)

    Lyman, J.T.; Ainsworth, E.J.; Alpen, E.L.; Bond, V.; Curtis, S.B.; Fry, R.J.M.; Jackson, K.L.; Nachtwey, S.; Sondhaus, C.; Tobias, C.A.; Fabrikant, J.I.

    1980-11-01

    The radiation risks to the health of workers who will construct and maintain solar power satellites in the space environment were examined. For ionizing radiation, the major concern will be late or delayed health effects, particularly the increased risk of radiation-induced cancer. The estimated lifetime risk for cancer is 0.8 to 5.0 excess deaths per 10,000 workers per rad of exposure. Thus, for example, in 10,000 workers who completed ten missions with an exposure of 40 rem per mission, 320 to 2000 additional deaths in excess of the 1640 deaths from normally occurring cancer, would be expected. These estimates would indicate a 20 to 120% increase in cancer deaths in the worker-population. The wide range in these estimates stems from the choice of the risk-projection model and the dose-response relationsip. The choice between a linear and a linear-quadratic dose-response model may alter the risk estimate by a factor of about two. The method of analysis (e.g., relative vs absolute risk model) can alter the risk estimate by an additional factor of three. Choosing different age and sex distributions can further change the estimate by another factor of up to three. The potential genetic consequences could be of significance, but at the present time, sufficient information on the age and sex distribution of the worker population is lacking for precise estimation of risk. The potential teratogenic consequences resulting from radiation are considered significant. Radiation exposure of a pregnant worker could result in developmental abnormalities.

  7. A graded-gap detector for ionizing radiation

    CERN Document Server

    Pozhela, Y; Shilenas, A; Yasutis, V; Dapkus, L; Kinduris, A; Yutsene, V

    2002-01-01

    The current response to optical and X-ray radiation in graded-gap Al sub x Ga sub 1 sub - sub x As layers is investigated. Graded-gap electric field in Al sub x Ga sub 1 sub - sub x As layer of L = 15 mu m thickness, with x changing from 0 to 0.4 along the layer, makes it possible to get full accumulation of charge carriers generated by ionizing radiation and enables to achieve the current/power sensitivity of Al sub x Ga sub 1 sub - sub x As up to 0.25 A/W. It is shown that low-doped layer on the narrow-gap side of the Al sub x Ga sub 1 sub - sub x As graded-gap layer provide the volt/watt sensitivity to X-radiation with the energy lower than 15 keV up to 16 x 10 sup 3 V/W in the photovoltaic regime

  8. Learning From Biomarkers in Victims Accidentally Exposed to Ionizing Radiation

    Institute of Scientific and Technical Information of China (English)

    Yan Wang; Liqing Du; Chang Xu; Qin Wang; Zhiyi Song; Jianxiang Liu; Xu Su

    2016-01-01

    Biomarkers,such as chromosome aberration and micronuclei assays,prove to be reliable for facilitating clinical diagnosis in radiation accidents.In a radiation accident in India,chromosomal aberration,γ-H2AX,as well as other blood markers,were detected in accidentally exposed victims.This multi-parametric approach aided in confirming that individuals had been exposed by ionizing radiation.However,doses were impossible to estimate because of a 30-day delay in accident awareness.Exposure dose for victims was estimated using a dose-response curve previously established.Dose estimation,blood cell depletion kinetics,and no appearance of prodromal symptoms suggested that doses of exposure were low.Hematologic investigation,sampling time,and chromosome aberration scoring were all proposed according to data from the victims exposed to 60Co.Finally,knowledge regarding chromosome aberration analysis and the importance of international co-operation and assistance should be shared from this accident.

  9. Interaction between {beta}-Lapachone and Ionizing Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Eun Kyung; Song, Si Yeol; Shin, Seong Soo; Lee, Sang Wook; Ahn, Seung Do; Kim, Jong Hoon [College of Medicine, University of Ulsan, Seoul (Korea, Republic of); Park, Heon Joo [College of Medicine, Inha University, Incheon (Korea, Republic of); Song, Chang Won [University of Minnesota Medical School, Minneapolis (United States)

    2006-07-01

    {beta}-Lapachone (3,4-dihydro-2,2-dimethyl-2Hnaphtho[ 1,2-b]pyran-5,6-dione)({beta}-lap) was originally isolated from the bark of the Lapacho tree growing in South America (1). This drug has attracted considerable interest in recent years because of its potent cytotoxicity against various cancer cell lines through a mechanism that works independent of the cell cycle of p53 status. Interestingly, {beta}-lap has been reported to react synergistically with Taxol, mitomycin C, genistein, and ionizing radiation (IR) (2-3) in vitro against cultured cancer cells. It has also been reported that {beta}-lap inhibits the repair of potentially lethal radiation damage by converting repairable single-stranded DNA breaks into repair-resistant, double-stranded DNA breaks. Thus {beta}- lap has been thought to act as a radiation sensitizer by inhibiting DNA damage repair. In the present study, we observed that IR sensitizes cancer cells to {beta}-lap. It thus appeared that the synergistic interaction of IR and {beta}-lap in killing cancer cells was due to an increase in cellular susceptibility to {beta}-lap, probably in addition to {beta}-lap. induced radiosensitization.

  10. What happens when spins meet for ionizing radiation dosimetry?

    Science.gov (United States)

    Pavoni, Juliana F.; Neves-Junior, Wellington F. P.; Baffa, Oswaldo

    2016-07-01

    Electron spin resonance (ESR) and magnetic resonance imaging (MRI) can be used to measure radiation dose deposited in different milieu through its effects. Radiation can break chemical bonds and if they produce stable free radicals, ESR can measure their concentration through their spins and a dose can be inferred. Ionizing radiation can also promote polymerization and in this case proton relaxation times can be measured and an image weighed by T2 can be produced giving spatial information about dose. A review of the basics of these applications is presented concluding with an end-to-end test using a composite Gel-Alanine phantom to validate 3-dimensionally dose distribution delivered in a simulation of Volume Modulated Arch Therapy on the simultaneous treatment of multiple brain metastases. The results obtained with the gel and alanine dosimeters are consistent with the expected by the treatment planning system, showing the potential of this multidosimetric approach and validating dosimetrically the multiple brain metastases treatment using VMAT.

  11. Rydberg atoms in astrophysics

    CERN Document Server

    Gnedin, Yu N; Ignjatovic, Lj M; Sakan, N M; Sreckovic, V A; Zakharov, M Yu; Bezuglov, N N; Klycharev, A N; 10.1016/j.newar.2009.07.003

    2012-01-01

    Elementary processes in astrophysical phenomena traditionally attract researchers attention. At first this can be attributed to a group of hemi-ionization processes in Rydberg atom collisions with ground state parent atoms. This processes might be studied as a prototype of the elementary process of the radiation energy transformation into electrical one. The studies of nonlinear mechanics have shown that so called regime of dynamic chaos should be considered as typical, rather than exceptional situation in Rydberg atoms collision. From comparison of theory with experimental results it follows that a such kind of stochastic dynamic processes, occurred during the single collision, may be observed.

  12. Response of ionization chamber based pocket dosimeter to beta radiation.

    Science.gov (United States)

    Kumar, Munish; Gupta, Anil; Pradhan, S M; Bakshi, A K; Chougaonkar, M P; Babu, D A R

    2013-12-01

    Quantitative estimate of the response of ionization chamber based pocket dosimeters (DRDs) to various beta sources was performed. It has been established that the ionization chamber based pocket dosimeters do not respond to beta particles having energy (Emax)1 MeV, the DRDs exhibit measureable response and the values are ~8%, ~14% and ~27% per mSv for natural uranium, (90)Sr/(90)Y and (106)Ru/(106)Rh beta sources respectively. As the energy of the beta particles increases, the response also increases. The response of DRDs to beta particles having energy>1 MeV arises due to the fact that the thickness of the chamber walls is less than the maximum range of beta particles. This may also be one of the reasons for disparity between doses measured with passive/legal dosimeters (TLDs) and DRDs in those situations in which radiation workers are exposed to mixed field of gamma photons and beta particles especially at uranium processing plants, nuclear (power and research) reactors, waste management facilities and fuel reprocessing plants etc. The paper provides the reason (technical) for disparity between the doses recorded by TLDs and DRDs in mixed field of photons and beta particles.

  13. Scattered ionizing radiations from low-energy focus plasma and radiation dosimetery assessment

    Indian Academy of Sciences (India)

    G M El-Arag; M A Ayad; M A El-Kolaly; W Madcour

    2010-10-01

    Scattered ionizing radiation emissions from a low-energy plasma focus (0.1 kJ Mather-type) device operating with different gases were studied. The plasma focus device was powered by a capacitor bank of 1 F at 18 kV maximum charging voltage. The radiation emissions were investigated using time-integrated thermoluminescence TLD-500. These detectors were calibrated against standard X-ray machine as well as standard sources (60Co and 137Ca). Calibration of detectors showed linear relation over all the region of measurements. It was found that radiation levels would be minimum for different gases, when the gas pressure was between 0.5 and 0.8 Torr. Only helium deviated from this phenomenon as it gave maximum radiation level at 0.8 Torr pressure. It was also found that, for all the gases used, the radiation levels were maximum when the applied voltage was 15 keV.

  14. Transient optical gratings for pulsed ionizing radiation studies

    CERN Document Server

    Fullagar, Wilfred K; Hall, Chris J

    2011-01-01

    Prior to the invention of holography or lasers, Bragg's X-ray microscope opened the door to optical computation in short-wavelength studies using spatially coherent visible light, including phase retrieval methods. This optical approach lost ground to semiconductor detection and digital computing in the 1960s. Since then, visible optics including spatial light modulators (SLMs), array detectors and femtosecond lasers have become widely available, routinely allowing versatile and computer-interfaced imposition of optical phase, molecular coherent control, and detection. Today, high brilliance X-ray sources begin to offer opportunities for atomic resolution and ultrafast pump-probe studies. Correspondingly, this work considers an overlooked aspect of Bragg's X-ray microscope - the incoherent ionizing radiation to coherent visible (IICV) conversion that is a necessary prerequisite for coherent optical computations. Technologies are suggested that can accomplish this conversion. Approaches to holographic data sto...

  15. Effects on vegetable seeds due to non ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Acri, G.; Oliva, A.; Falcone, G. [Universita della Calabria, Dipt. di Fisica, Cosenza (Italy); Acri, G.; Testagrossa, B.; Vermiglio, G.; Tripepi, M.G. [Universita della Calabria, Dipt. di Ecologia, Cosenza (Italy); Bitonti, M.B.; Chiappetta, A. [Universita di Messina, Dipt. di Protezionistica Ambientale, Sanitaria, Sociale ed Industriale, Messina (Italy)

    2006-07-01

    Based on the tightly relationship between light and plants growth and development, the present work aims to obtain some further insight into the effects of non ionizing radiation the photo-autotrophic organisms, due to the relevant implications for both scientific knowledge and economical and social effects. In this context, a set of experiments was conducted to investigate the influence of a long-lasting exposition to both RF at 1850 MHz and polarized light source on roots elongation of corn kernels. The radical apparatus was chosen as a sensible parameter and the elongation of the roots was monitored as a function of time. Mitotic index and length of meta-xylem cells were estimated in root apex as an index of cell proliferation and cell expansion activity, respectively. (N.C.)

  16. 21 CFR 579.22 - Ionizing radiation for treatment of animal diets.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ionizing radiation for treatment of animal diets... for treatment of animal diets. Ionizing radiation for treatment of complete diets for animals may be... Bagged complete diets, packaged feeds, feed ingredients, bulk feeds, animal treats and chews...

  17. Effect of low dose ionizing radiation upon concentration of

    Energy Technology Data Exchange (ETDEWEB)

    Viliae, M.; Kraljeviae, P.; Simpraga, M.; Miljaniae, S.

    2004-07-01

    It is known that low dose ionizing radiation might have stimulating effects (Luckey, 1982, Kraljeviae, 1988). This fact has also been confirmed in the previous papers of Kraljeviae et al. (2000-2000a; 2001). Namely, those authors showed that irradiation of chicken eggs before incubation by a low dose of 0.15 Gy gamma radiation increases the activity aspartateaminotrasferases (AST) and alanine-aminotransferases (ALT) in blood plasma of chickens hatched from irradiated eggs, as well as growth of chickens during the fattening period. Low doses might also cause changes in the concentration of some biochemical parameters in blood plasma of the same chickens such as changes in the concentration of total proteins, glucose and cholesterol. In this paper, an attempt was made to investigate the effects of low dose gamma radiation upon the concentration of sodium and potassium in the blood plasma of chickens which were hatched from eggs irradiated on the 19th day of incubation by dose of 0.15 Gy. Obtained results were compared with the results from the control group (chickens hatched from nonirradiated eggs). After hatching, all other conditions were the same for both groups. Blood samples were drawn from heart, and later from the wing vein on days 1, 3, 5, 7, 10, 20, 30 and 42. The concentration of sodium and potassium was determined spectrophotometrically by atomic absorbing spectrophotometer Perkin-Elmer 1100B. The concentration of sodium and potassium in blood plasma of chickens hatched from eggs irradiated on the 19th day of incubation by dose of 0.15 Gy indicated a statistically significant increase (P>0.01) only on the first day of the experiment. Obtained results showed that irradiation of eggs on the 19th day of incubation by dose of 0.15 Gy gamma radiation could have effects upon the metabolism of electrolytes in chickens. (Author)

  18. Evaluation of exposure to ionizing radiation among gamma camera operators

    Directory of Open Access Journals (Sweden)

    Agnieszka Anna Domańska

    2013-08-01

    Full Text Available Background: Protection of nuclear medicine unit employees from hazards of the ionizing radiation is a crucial issue of radiation protection services. We aimed to assess the severity of the occupational radiation exposure of technicians performing scintigraphic examinations at the Nuclear Medicine Department, Central Teaching Hospital of Medical University in Łódź, where thousands of different diagnostic procedures are performed yearly. Materials and Methods: In 2013 the studied diagnostic unit has employed 10 technicians, whose exposure is permanently monitored by individual dosimetry. We analyzed retrospective data of quarterly doses in terms of Hp(10 dose equivalents over the years 2001-2010. Also annual and five-year doses were determined to relate the results to current regulations. Moreover, for a selected period of one year, we collected data on the total activity of radiopharmaceuticals used for diagnostics, to analyze potential relationship with doses recorded in technicians performing the examinations. Results: In a 10-year period under study, the highest annual dose recorded in a technician was 2 mSv, which represented 10% of the annual dose limit of 20 mSv. The highest total dose for a 5-year period was 7.1 mSv, less than 10% of a 5-year dose limit for occupational exposure. Positive linear correlation was observed between total activity of radiopharmaceuticals used for diagnostics in the period of three months and respective quarterly doses received by technicians performing examinations. Conclusions: Doses received by nuclear medicine technicians performing diagnostic procedures in compliance with principles of radiation protection are low, which is confirmed by recognizing the technicians of this unit as B category employees. Med Pr 2013;64(4:503–506

  19. Effects of Ionizing Radiation on Postharvest Fungal Pathogens

    Directory of Open Access Journals (Sweden)

    Rae-Dong Jeong

    2015-06-01

    Full Text Available Postharvest diseases cause losses in a wide variety of crops around the world. Irradiation, a useful nonchemical approach, has been used as an alternative treatment for fungicide to control plant fungal pathogens. For a preliminary study, ionizing radiations (gamma, X-ray, or e-beam irradiation were evaluated for their antifungal activity against Botrytis cinerea, Penicillium expansum, and Rhizopus stolonifer through mycelial growth, spore germination, and morphological analysis under various conditions. Different fungi exhibited different radiosensitivity. The inhibition of fungal growth showed in a dose-dependent manner. Three fungal pathogens have greater sensitivity to the e-beam treatment compared to gamma or X-ray irradiations. The inactivation of individual fungal-viability to different irradiations can be considered between 3–4 kGy for B. cinerea and 1–2 kGy for P. expansum and R. stolonifer based on the radiosensitive and radio-resistant species, respectively. These preliminary data will provide critical information to control postharvest diseases through radiation.

  20. 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

  1. General relativistic radiative transfer in hot astrophysical plasmas a characteristic approach

    CERN Document Server

    Zane, S; Nobili, L; Erna, M; Zane, Silvia; Turolla, Roberto; Nobili, Luciano; Erna, Myris

    1996-01-01

    In this paper we present a characteristic method for solving the transfer equation in differentially moving media in a curved spacetime. The method is completely general, but its capabilities are exploited at best in presence of symmetries, when the existence of conserved quantities allows to derive analytical expressions for the photon trajectories in phase space. In spherically--symmetric, stationary configurations the solution of the transfer problem is reduced to the integration of a single ordinary differential equation along the bi--parametric family of characteristic rays. Accurate expressions for the radiative processes relevant to continuum transfer in a hot astrophysical plasma have been used in evaluating the source term, including relativistic e--p, e--e bremsstrahlung and Compton scattering. A numerical code for the solution of the transfer problem in moving media in a Schwarzschild spacetime has been developed and tested. Some applications, concerning ``hot'' and ``cold'' accretion onto non--rot...

  2. Determining astrophysical three-body radiative capture reaction rates from inclusive Coulomb break-up measurements

    CERN Document Server

    Casal, J; Arias, J M; Gómez-Camacho, J

    2016-01-01

    A relationship between the Coulomb inclusive break-up probability and the radiative capture reaction rate for weakly-bound three-body systems is established. This direct link provides a robust procedure to estimate the reaction rate for nuclei of astrophysical interest by measuring inclusive break-up processes at different energies and angles. This might be an advantageous alternative to the determination of reaction rates from the measurement of $B(E1)$ distributions through exclusive Coulomb break-up experiments. In addition, it provides a reference to assess the validity of different theoretical approaches that have been used to calculate reaction rates. The procedure is applied to $^{11}$Li ($^{9}$Li+n+n) and $^6$He ($^{4}$He+n+n) three-body systems for which some data exist.

  3. Determining astrophysical three-body radiative capture reaction rates from inclusive Coulomb break-up measurements

    Science.gov (United States)

    Casal, J.; Rodríguez-Gallardo, M.; Arias, J. M.; Gómez-Camacho, J.

    2016-04-01

    A relationship between the Coulomb inclusive break-up probability and the radiative capture reaction rate for weakly bound three-body systems is established. This direct link provides a robust procedure to estimate the reaction rate for nuclei of astrophysical interest by measuring inclusive break-up processes at different energies and angles. This might be an advantageous alternative to the determination of reaction rates from the measurement of B (E 1 ) distributions through exclusive Coulomb break-up experiments. In addition, it provides a reference to assess the validity of different theoretical approaches that have been used to calculate reaction rates. The procedure is applied to 11Li (9Li+n +n ) and 6He (4He+n +n ) three-body systems for which some data exist.

  4. Ionizing radiation and mitogenetic radiation: two links of the same energetic chain in a biological cell.

    Science.gov (United States)

    Goraczko, W

    2000-03-01

    Present research demonstrates that the excitation of living systems by high energy/low doses of ionizing radiation (IR) initiates prolonged secondary ultraviolet (UV) range emission that influences biota. When doses of this energy are too high, the process of energy or radiation absorption by the cells causes negative changes (i.e. negative mutations or death). When these doses are sufficiently low, vital processes inside the cells are stimulated and can create positive changes. This paper proposes a common denomination for mechanisms of UV and ionizing radiation when interacting with living cells, underlying both its mitogenetic effect and radiation hormesis. Data from radon exposure in chronically exposed nuclear workers, acutely exposed Hiroshima and Nagasaki victims and observers of atmospheric nuclear explosions, combined with animal results, present irrefutable evidence that low doses of IR are beneficial. As a conclusion the author postulates the possibility of new methods of therapy regarding the use of IR and mitogenetic radiation. This paper has been written to encourage debate regarding possible future benefits that may be derived from low level doses of IR exposure in the general population.

  5. Interaction of ionizing radiation with mater; Oddzialywanie promieniowania jonizujacego z materia

    Energy Technology Data Exchange (ETDEWEB)

    Pogocki, D. [Institute of Nuclear Chemistry and Technology, Warsaw (Poland)

    1997-10-01

    The early radiation effects (e.g. excitation, ionization) have been described and compared for different kind of radiation interacting with mater. The mechanism of energy deposition in connection with radiation dose and their spatial distribution has been shown.The commonly used definitions and units in radiation dosimetry have been also reviewed. 4 refs, 4 figs.

  6. Cardiovascular risks associated with low dose ionizing particle radiation.

    Directory of Open Access Journals (Sweden)

    Xinhua Yan

    Full Text Available Previous epidemiologic data demonstrate that cardiovascular (CV morbidity and mortality may occur decades after ionizing radiation exposure. With increased use of proton and carbon ion radiotherapy and concerns about space radiation exposures to astronauts on future long-duration exploration-type missions, the long-term effects and risks of low-dose charged particle irradiation on the CV system must be better appreciated. Here we report on the long-term effects of whole-body proton ((1H; 0.5 Gy, 1 GeV and iron ion ((56Fe; 0.15 Gy, 1GeV/nucleon irradiation with and without an acute myocardial ischemia (AMI event in mice. We show that cardiac function of proton-irradiated mice initially improves at 1 month but declines by 10 months post-irradiation. In AMI-induced mice, prior proton irradiation improved cardiac function restoration and enhanced cardiac remodeling. This was associated with increased pro-survival gene expression in cardiac tissues. In contrast, cardiac function was significantly declined in (56Fe ion-irradiated mice at 1 and 3 months but recovered at 10 months. In addition, (56Fe ion-irradiation led to poorer cardiac function and more adverse remodeling in AMI-induced mice, and was associated with decreased angiogenesis and pro-survival factors in cardiac tissues at any time point examined up to 10 months. This is the first study reporting CV effects following low dose proton and iron ion irradiation during normal aging and post-AMI. Understanding the biological effects of charged particle radiation qualities on the CV system is necessary both for the mitigation of space exploration CV risks and for understanding of long-term CV effects following charged particle radiotherapy.

  7. The scrapie disease process is unaffected by ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Fraser, H.; Farquhar, C.F.; McConnell, I.; Davies, D. (AFRC MRC Neuropathogenesis Unit, Edinburgh (England))

    1989-01-01

    The incubation period of scrapie, its degenerative neuropathology and the replication of its causal unconventional virus are all tightly controlled parameters of the experimental disease in mice. Each parameter can vary depending on the strain and dose of virus, on the route of infection, and on the host genotype. Exposure to whole-body gamma-irradiation from Cesium 137 has no effect on the progress or development of the disease, based on the three independent indices of incubation period, neuropathology, or infectibility by high or low doses of virus. These results are based on an extensive series of experiments in many mouse strains and are consistent using different strains (ME7, 22A, 79A, 87V) and doses of virus, routes of infection, timing and dose of radiation (3-15 Gy) administered as single or fractionated exposures with or without bone-marrow (b.m.) replacement therapy. Levels of infection in the spleen are unaltered after lethal whole-body irradiation of the scrapie-infected host, despite several-fold reductions in tissue mass due to the loss of proliferating myeloid and lymphoid precursor cells and their progeny. Contrary to our earlier suggestion, scrapie infection with the 22A virus does not reduce the effectiveness of post-exposure bone-marrow replacements to recolonize an infected host after repeated ionizing radiation totalling 15Gy. This work narrows the search for the candidate cells and biosynthetic systems which replicate the virus in the lymphoreticular and central nervous systems. Many programmed cellular events are radiation sensitive but protein synthesis is extremely radioresistant.

  8. The Inhibitory Effects of Low-Dose Ionizing Radiation in IgE-Mediated Allergic Responses.

    Directory of Open Access Journals (Sweden)

    Hae Mi Joo

    Full Text Available Ionizing radiation has different biological effects according to dose and dose rate. In particular, the biological effect of low-dose radiation is unclear. Low-dose whole-body gamma irradiation activates immune responses in several ways. However, the effects and mechanism of low-dose radiation on allergic responses remain poorly understood. Previously, we reported that low-dose ionizing radiation inhibits mediator release in IgE-mediated RBL-2H3 mast cell activation. In this study, to have any physiological relevance, we investigated whether low-dose radiation inhibits allergic responses in activated human mast cells (HMC-1(5C6 and LAD2 cells, mouse models of passive cutaneous anaphylaxis and the late-phase cutaneous response. High-dose radiation induced cell death, but low-dose ionizing radiation of <0.5 Gy did not induce mast cell death. Low-dose ionizing radiation that did not induce cell death significantly suppressed mediator release from human mast cells (HMC-1(5C6 and LAD2 cells that were activated by antigen-antibody reaction. To determine the inhibitory mechanism of mediator released by low-dose ionizing radiation, we examined the phosphorylation of intracellular signaling molecules such as Lyn, Syk, phospholipase Cγ, and protein kinase C, as well as the intracellular free Ca2+ concentration ([Ca2+]i. The phosphorylation of signaling molecules and [Ca2+]i following stimulation of FcεRI receptors was inhibited by low dose ionizing radiation. In agreement with its in vitro effect, ionizing radiation also significantly inhibited inflammatory cells infiltration, cytokine mRNA expression (TNF-α, IL-4, IL-13, and symptoms of passive cutaneous anaphylaxis reaction and the late-phase cutaneous response in anti-dinitrophenyl IgE-sensitized mice. These results indicate that ionizing radiation inhibits both mast cell-mediated immediate- and delayed-type allergic reactions in vivo and in vitro.

  9. Ionizing radiation effects on the matter and its applications in research and industry

    Energy Technology Data Exchange (ETDEWEB)

    Cruz Z, E. [Instituto de Ciencias Nucleares, UNAM, Ciudad Universitaria, Mexico 04510, D. F. (Mexico); Martinez B, G. [Laboratorio de Investigacion y Desarrollo de Materiales Avanzados, Facultad de Quimica, Universidad Autonoma del Estado de Mexico, Km. 12 Carretera Toluca-Atlacomulco, San Cayetano 50200, Estado de Mexico (Mexico)], e-mail: ecruz@nucleares.unam.mx

    2009-07-01

    Ionizing radiation as alpha and beta particles, electron accelerated, neutron particle, and X-rays and photons with relative high energy, as an useful radiation tool for many applications. the last two kind radiations are know as electromagnetic radiation. The radiation effects on the matter are well know that produces about fourteen processes during interaction with solids, aqueous solution and gases. In applications, commonly it depends of the nature and interest on the material samples that their characteristics can modify with the energy deposited on them. This part is devoted to more important effects produced by ionizing radiation with the matter and talk about the wide range applications recently; crystals radiation detectors and for application in medicine, detection of foodstuffs irradiated for preservation, and the application of ionizing radiation on polymeric materials. (Author)

  10. Modulating Radiation Resistance: Novel Protection Paradigms Based on Defenses against Ionizing Radiation in the Extremophile Deinococcus radiodurans

    Science.gov (United States)

    2010-05-10

    cellular damge caused by ionizing radiation and ultraviolet light. Deinococcus radiodurans; Lactobacillus plantarurn; cyanobacteria ; radiation...6 3. K. S. Makarova and MICHAEL J. DALY (2010) Comparative genomics of stress response systems in Deinococcus bacteria. Bacterial Stress Responses...In Press) Abstract | The prospect of comparative genomics resolving the seemingly paradoxical mechanism of extreme radiation resistance in

  11. Ionizing radiation effects on food vitamins: a review

    Directory of Open Access Journals (Sweden)

    Ana Paula Dionísio

    2009-10-01

    Full Text Available Ionizing radiation has been widely used in industrial processes, especially in the sterilization of medicals, pharmaceuticals, cosmetic products, and in food processing. Similar to other techniques of food processing, irradiation can induce certain alterations that can modify both the chemical composition and the nutritional value of foods. These changes depend on the food composition, the irradiation dose and factors such as temperature and presence or absence of oxygen in the irradiating environment. The sensitivity of vitamins to radiation is unpredictable and food vitamin losses during the irradiation are often substantial. The aim of this study was to discuss retention or loss of vitamins in several food products submitted to an irradiation process.Assim como outras técnicas de processamento de alimentos, a irradiação induz certas alterações, que podem modificar a composição química e o valor nutritivo dos alimentos. A natureza e extensão destas mudanças dependem essencialmente da composição do alimento, da dose de irradiação e de fatores tais como a temperatura e a presença ou ausência do oxigênio do ar. Enquanto que algumas vitaminas, como a riboflavina, niacina e vitamina D são bastante estáveis, outras, como a tiamina e vitaminas A e E, são relativamente lábeis. O objetivo da presente revisão foi discutir as prováveis perdas de vitaminas de diversos produtos submetidos ao processo de irradiação.

  12. Indirect measurement of radiative capture cross sections relevant in astrophysical scenarios

    Science.gov (United States)

    Pramanik, Ushasi Datta

    2007-07-01

    Radiative capture cross sections play a significant role in many cosmic phenomena, e.g. galactic evolution, star formation and planet formation etc. In explosive stellar burning scenarios, a large number of unstable nuclei play a crucial role, and reliable reaction cross sections are necessary for astrophysical model calculations, which will help in turn to understand the phenomena. A number of indirect methods are being explored by experimental nuclear physicists to avoid radioactive targets and other difficulties of direct measurements of radiative capture cross sections. The Coulomb dissociation of radioactive ion beams at intermediate energy is one of the most powerful indirect methods for measuring capture cross sections, and is being explored at various laboratories in the world. Here, a brief current status report is presented. This indirect method has a number of advantages compared to direct measurements, but there are also a number of limitations to this method with the presently available experimental facilities. A discussion on these aspects is given, together with an outlook on future experimental prospects.

  13. 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

  14. Synthesis of silver nanoparticles in hydrogels crosslinked by ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Alcantara, Maria Tania S.; Oliani, Washington L.; Brant, Antonio J.C.; Oliveira, Maria Jose A. de; Riella, Humberto Gracher; Lugao, Ademar B., E-mail: maratalcantara@uol.com.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    Hydrogel is defined as a polymeric material which exhibits the ability to swell and retain a significant fraction of water within its structure without dissolving the polymeric network. Silver nanoparticles (AgNPs) are used in a range of medicinal products based on hydrogels and diverse other products due to their antibacterial properties at low concentrations. The use of ionizing radiation in the production process of hydrogels of poly(N-vinyl-2-pyrrolidone) (PVP) and poly(vinyl alcohol) (PVA) in aqueous solutions enables the crosslinking of their polymer chains. If polymer solutions contain Ag{sup +} ions, these can be reduced radiolytically to nanocrystalline silver. The objective of this study was to investigate the reduction of Ag{sup +} ions by gamma-irradiation for the synthesis of AgNPs in hydrogels of PVA and PVP as main polymers and to make a comparison of the performance of the two polymeric matrices, chiefly focusing on the effect of the AgNPs' synthesis on the crosslinking of both polymers. The properties of the hydrogel matrices obtained were evaluated from tests of gel fraction, swelling in water, and stress-strain. The results of mechanical properties of PVA matrix were higher than those of PVP one whereas the latter exhibited a higher swelling degree. The reduction of silver ions was confirmed by UV-visible absorption spectrum, whose characteristics also indicated the formation of silver nanoparticles in both arrays. (author)

  15. 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

  16. Ionizing radiation induces heritable disruption of epithelial cell interactions

    Science.gov (United States)

    Park, Catherine C.; Henshall-Powell, Rhonda L.; Erickson, Anna C.; Talhouk, Rabih; Parvin, Bahram; Bissell, Mina J.; Barcellos-Hoff, Mary Helen; Chatterjee, A. (Principal Investigator)

    2003-01-01

    Ionizing radiation (IR) is a known human breast carcinogen. Although the mutagenic capacity of IR is widely acknowledged as the basis for its action as a carcinogen, we and others have shown that IR can also induce growth factors and extracellular matrix remodeling. As a consequence, we have proposed that an additional factor contributing to IR carcinogenesis is the potential disruption of critical constraints that are imposed by normal cell interactions. To test this hypothesis, we asked whether IR affected the ability of nonmalignant human mammary epithelial cells (HMEC) to undergo tissue-specific morphogenesis in culture by using confocal microscopy and imaging bioinformatics. We found that irradiated single HMEC gave rise to colonies exhibiting decreased localization of E-cadherin, beta-catenin, and connexin-43, proteins necessary for the establishment of polarity and communication. Severely compromised acinar organization was manifested by the majority of irradiated HMEC progeny as quantified by image analysis. Disrupted cell-cell communication, aberrant cell-extracellular matrix interactions, and loss of tissue-specific architecture observed in the daughters of irradiated HMEC are characteristic of neoplastic progression. These data point to a heritable, nonmutational mechanism whereby IR compromises cell polarity and multicellular organization.

  17. MicroRNAs, cancer and ionizing radiation: Where are we?

    Directory of Open Access Journals (Sweden)

    Gustavo Nader Marta

    2015-06-01

    Full Text Available Summary The aim of this study is to describe the biogenesis of microRNA, its relations with carcinogenesis, and the correlation between microRNA and ionizing radiation (IR, focusing on radioresponsiveness. It is known that microRNA biogenesis is well established and involves different enzymatic cleavages, resulting in the production of mature microRNA. MicroRNAs are involved in carcinogenesis. Their interaction is related to the genetic and epigenetic changes associated with activation of proto-oncogenes or inactivation of tumor suppressor genes. Several studies have shown that the levels of expression of some microRNAs vary significantly after irradiation. There are evidences that microRNAs can influence cellular response after IR. In addition, microRNAs are related to modulation of the expression of several post-transcriptional targets in DNA damage response pathways, and to the DNA damage repair regulation mechanism. Future studies can clarify a possible clinical use of microRNAs as a new class of radiosensitive agents.

  18. 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...

  19. High-throughput identification of ionizing radiation-sensitive plant genes and development of radiation indicator plant and radiation sensing Genechip

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Sub; Kim, Jinbaek; Ha, Bokeun; Kim, Sang Hoon; Kim, Sunhee

    2013-05-15

    Physiological analysis of monocot model plant (rice) in response to ionizing radiation (cosmic-ray, gamma-ray, Ion beam). - Identification of antioxidant characters through cytochemical analysis. - Comparison of antioxidant activities in response to ionizing irradiation. - Evaluation of anthocyanin quantity in response to ionizing irradiation. Ionization energy response gene family analysis via bioinformatic validation. - Expression analysis of monocot and dicot gene families. - In silico and bioinformatic approach to elucidate gene function. Characterization and functional analysis of genes specifically expressed in response to ionizing irradiation (cosmic-ray, gamma-ray, Ion beam). - High throughput trancriptomic analysis of plants under ionizing radiation using microarray. - Promotor and cis-element analysis of genes specifically expressed in response to ionizing radiation. - Validation and function analysis of candidate genes. - Elucidation of plant mechanism of sensing and response to ionization energy. Development of bioindicator plants detecting ionization energy. - Cloning and identification of 'Radio marker genes (RMG)'. - Development of Over-expression (O/E) or Knock-out (K/O) plant using RMG. Development of Genechip as an ionization energy detector. - Expression profiling analysis of genes specifically expression in response to ionization energy. - Prepare high-conserved gene specific oligomer. - Development of ionization energy monitoring Genechip and application.

  20. Ionizing radiation exposure in interventional cardiology: current radiation protection practice of invasive cardiology operators in Lithuania.

    Science.gov (United States)

    Valuckiene, Zivile; Jurenas, Martynas; Cibulskaite, Inga

    2016-09-01

    Ionizing radiation management is among the most important safety issues in interventional cardiology. Multiple radiation protection measures allow the minimization of x-ray exposure during interventional procedures. Our purpose was to assess the utilization and effectiveness of radiation protection and optimization techniques among interventional cardiologists in Lithuania. Interventional cardiologists of five cardiac centres were interviewed by anonymized questionnaire, addressing personal use of protective garments, shielding, table/detector positioning, frame rate (FR), resolution, field of view adjustment and collimation. Effective patient doses were compared between operators who work with and without x-ray optimization. Thirty one (68.9%) out of 45 Lithuanian interventional cardiologists participated in the survey. Protective aprons were universally used, but not the thyroid collars; 35.5% (n  =  11) operators use protective eyewear and 12.9% (n  =  4) wear radio-protective caps; 83.9% (n  =  26) use overhanging shields, 58.1% (n  =  18)-portable barriers; 12.9% (n  =  4)-abdominal patient's shielding; 35.5% (n  =  11) work at a high table position; 87.1% (n  =  27) keep an image intensifier/receiver close to the patient; 58.1% (n  =  18) reduce the fluoroscopy FR; 6.5% (n  =  2) reduce the fluoro image detail resolution; 83.9% (n  =  26) use a 'store fluoro' option; 41.9% (N  =  13) reduce magnification for catheter transit; 51.6% (n  =  16) limit image magnification; and 35.5% (n  =  11) use image collimation. Median effective patient doses were significantly lower with x-ray optimization techniques in both diagnostic and therapeutic interventions. Many of the ionizing radiation exposure reduction tools and techniques are underused by a considerable proportion of interventional cardiology operators. The application of basic radiation protection tools and

  1. Mars Radiation Risk Assessment and Shielding Design for Long-term Exposure to Ionizing Space Radiation

    Science.gov (United States)

    Tripathi, Ram K.; Nealy, John E.

    2007-01-01

    NASA is now focused on the agency's vision for space exploration 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 is committed to the safety of the missions and the crew, and there is an overwhelming emphasis on the reliability issues for space missions and the habitat. The cost-effective design of the spacecraft demands a very stringent requirement on the optimization process. Exposure from the hazards of severe space radiation in deep space and/or long duration missions is a critical design constraint and a potential 'show stopper'. Thus, protection from the hazards of severe space radiation is of paramount importance to the agency's vision. It is envisioned to have long duration human presence on the Moon for deep space exploration. The exposures from ionizing radiation - galactic cosmic radiation and solar particle events - and optimized shield design for a swing-by and a long duration Mars mission have been investigated. It is found that the technology of today is inadequate for safe human missions to Mars, and revolutionary technologies need to be developed for long duration and/or deep space missions. The study will provide a guideline for radiation exposure and protection for long duration missions and career astronauts and their safety.

  2. Ionizing radiation post-curing of objects produced by stereolithography and other methods

    Science.gov (United States)

    Howell, David H.; Eberle, Claude C.; Janke, Christopher J.

    2000-01-01

    An object comprised of a curable material and formed by stereolithography or another three-dimensional prototyping method, in which the object has undergone initial curing, is subjected to post-curing by ionizing radiation, such as an electron beam having a predetermined beam output energy, which is applied in a predetermined dosage and at a predetermined dose rate. The post-cured object exhibits a property profile which is superior to that which existed prior to the ionizing radiation post-curing.

  3. Low energy behavior of astrophysical S factor in radiative captures to loosely bound final states

    CERN Document Server

    Mukhamedzhanov, A M

    2002-01-01

    The low-energy behavior of the astrophysical S-factor for E1 direct radiative captures a(p,gamma)b leading to loosely bound final states (b=a+p) is investigated. We derive a first-order integral representation for S(E) and focus on the properties around zero energy. We show that it is the competition between various effects, namely the remnant Coulomb barrier, the initial and final centrifugal barriers and the binding energy, that defines the behavior of the S(E->0). Contrary to previous findings, we prove that S(E->0) is not determined by the pole corresponding to the bound state. The derivative S'(0) increases with the increase of the centrifugal barrier, while it decreases with the charge of the target. For l_i=l_f+1 the increase of the binding energy of the final nucleus increases the derivative S'(0) while for l_i=l_f-1 the opposite effect is found. We make use of our findings to explain the low energy behavior of the S-factors related to some notorious capture reactions: 7Be(p, gamma)8B, 14N(p,gamma)15O...

  4. Molecular mechanism of cellular reception of ionizing radiation and of activation of signal transduction pathway

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Keiji [Nagasaki Univ. (Japan). Faculty of Pharmaceutical Sciences

    1997-03-01

    The author reviewed what in cells receives ionizing radiation as a stress and which signal transduction pathway is activated to induce the stress reaction in the following order: Activation of protein kinase C (PKC) pathway by radiation, activation of MAP kinase superfamily by radiation, induction of p53 function by radiation, and radiation exposure and stress reaction pathway. Conclusion was as follows: Cellular receptors to radiation can be cell membrane and DNA. Membrane reception of radiation induces activation of tyrosine kinase and sphingomyelinase, which resulting in activation of PKC- and MAP kinase-mediated signal transduction. The signal generated in the nucleus participates in regulation of cell cycle and in DNA repair. Therefore, it seems that irradiation of ionizing radiation gives energy to various cellular receptor sites as well as DNA, which generate various independent signals to be transduced and accumulated in the nucleus, and leading to cellular response. (K.H.). 63 refs.

  5. Applications of the interaction of the radiations ionizations with the matter in medicine and industry.

    CERN Document Server

    Fornaro, L

    2000-01-01

    When the ionizing radiation interact with the matter different effects happen on the radiations and on the matter. Many of these effects have been used with very different ends giving place to applications in several fields, among those that stand out the applications in medicine and industry. Basically, two different dispositions exist: one in that the radiation crosses or retrodisperse in the material and another in that the radiation acts on and it modifies the material.

  6. Human exposition to non ionizing electromagnetic radiations. Legislation and base stations measurements

    Directory of Open Access Journals (Sweden)

    Alonso Alonso Alonso

    2004-12-01

    Full Text Available This work deals about measurement procedures of non-ionizing radiations and their recorded levels in practice. The analyzed radiation sources cover the most common broadcasting media such as AM and FM transmissions and the GSM mobile telephony base stations. These sources currently radiate locations with high density of population. Spanish radiation level regulations are briefly described and some possible improvements are pointed out. The measurement results are discussed.

  7. 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.

  8. Plasma astrophysics

    CERN Document Server

    Kaplan, S A; ter Haar, D

    2013-01-01

    Plasma Astrophysics is a translation from the Russian language; the topics discussed are based on lectures given by V.N. Tsytovich at several universities. The book describes the physics of the various phenomena and their mathematical formulation connected with plasma astrophysics. This book also explains the theory of the interaction of fast particles plasma, their radiation activities, as well as the plasma behavior when exposed to a very strong magnetic field. The text describes the nature of collective plasma processes and of plasma turbulence. One author explains the method of elementary

  9. Comet assay as a procedure for detecting possible genotoxicity induced by non-ionizing radiation

    Directory of Open Access Journals (Sweden)

    Zsuzsanna Nemeth

    2015-05-01

    In our laboratory we use comet assay for testing genotoxicity of non-ionizing radiation for more than ten years. In the experiments we use whole blood samples (human or dog, cell lines (e.g. H295R cell line or 3 dimensional in vitro skin tissue (epidermis models. In our protocol a slightly modified alkaline Comet assay method of Singh et al. (1988 is used. On our poster there will be presented a brief summary of our experiments with exposure to different types of radiation (ELF, RF, and intermediate frequency. In our protocols the non-ionizing radiation was often combined with ionizing radiation to see whether the non-ionizing radiation can influence the repair of the DNA damage induced by ionizing radiation. For the evaluation of the slides mainly Komet 4.0 image analysis system software (Kinetic Imaging, Liverpool, UK was used, but as we got familiarized with other methods for slide evaluation like grading the comets by visual scoring into 5 categories or the CaspLab software, the comparison of these three methods will be also presented.

  10. The impact of ionizing radiation on the formation of a supermassive star in the early Universe

    CERN Document Server

    Chon, Sunmyon

    2016-01-01

    A massive primordial halo near an intensely star forming galaxy may collapse into a supermassive star (SMS) and leave a massive black hole seed of about $10^5~M_{sun}$. To investigate the impact of ionizing radiation on the formation of an SMS from a nearby galaxy, we perform three-dimensional radiation hydrodynamical simulations by selecting a pair of massive dark matter halos forming at $z >10$. We find that rich structures such as clumps and filaments around the source galaxy shield the cloud from ionizing radiation. In fact, in some cases cloud collapse is accelerated under ionizing radiation. This fact suggests that the ionization of the cloud's surroundings helps its collapse. Only strong radiation at the early stage of structure formation can halt the cloud collapse, but this is much stronger than observationally allowed value. We also explored the effect of ionizing radiation on a sample of 68 halos by employing an analytical model and found that increase in the mean density of the gas between the SMS...

  11. Industrial applications of ionizing radiation in France; Zastosowanie przemyslowe promieniowania jonizujacego we Francji promieniowania jonizujacego

    Energy Technology Data Exchange (ETDEWEB)

    Icre, P. [CORFAR S.A., (France)

    1997-10-01

    The review of industrial applications of ionizing radiations in France has been done. The special attention has been paid on irradiation of minerals, polymers and biological materials.The perspectives of radiosterilization have been also discussed.The review of radiation sources commonly used in irradiation plants has been performed as well.

  12. National Laboratory of Ionizing Radiation Metrology - Brazilian CNEN; Laboratorio Nacional de Metrologia das Radiacoes Ionizantes

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1992-12-31

    The activities of the Brazilian National Laboratory of Ionizing Radiations Metrology are described. They include research and development of metrological techniques and procedures, the calibration of area radiation monitors, clinical dosemeters and other instruments and the preparation and standardization of reference radioactive sources. 4 figs., 13 tabs.

  13. Is Ionizing Radiation Harmful at any Exposure? An Echo That Continues to Vibrate.

    Science.gov (United States)

    Azzam, Edouard I; Colangelo, Nicholas W; Domogauer, Jason D; Sharma, Neha; de Toledo, Sonia M

    2016-03-01

    The health risks to humans and non-human biota exposed to low dose ionizing radiation remain ambiguous and are the subject of intense debate. The need to establish risk assessment standards based on the mechanisms underlying low-level radiation exposure has been recognized by regulatory agencies as critical to adequately protect people and to make the most effective use of national resources. Here, the authors briefly review evidence showing that the molecular and biochemical changes induced by low doses of radiation differ from those induced by high doses. In particular, an array of redundant and inter-related mechanisms act in both prokaryotes and eukaryotes to restore DNA integrity following exposures to relatively low doses of sparsely ionizing radiation. Furthermore, the radiation-induced protective mechanisms often overcompensate and minimize the mutagenic potential of the byproducts of normal oxidative metabolism. In contrast to adaptive protection observed at low doses of sparsely ionizing radiation, there is evidence that even a single nuclear traversal by a densely ionizing particle track can trigger harmful effects that spread beyond the traversed cell and induce damaging effects in the nearby bystander cells. In vivo studies examining whether exposure to low dose radiation at younger age modulates the latency of expression of age-related diseases such as cancer, together with studies on the role of genetic susceptibility, will further illuminate the magnitude of risk of exposure to low dose radiation.

  14. Features of manufacturing Cd1–xZnxTe ionizing radiation detector

    Directory of Open Access Journals (Sweden)

    Tomashik Z. F.

    2013-02-01

    Full Text Available The article describes a newly-developed method of manufacturing of an operating element of the Cd1–xZnxTe-detector of ionizing radiation with high sensitivity to low-energy gamma radiation of the americium 241Am radioactive isotope. The proposed two-step method of chemical surface treatment with the use of new bromine releasing polishing etchants significantly improves the quality of the detector material and increases its specific sensitivity to ionizing radiation. This allows to use smaller Cd1–xZnxTe plates, which results in lowering of the cost of detectors.

  15. Medical applications of ionizing radiation; Aplicaciones medicas de las radiaciones ionizantes

    Energy Technology Data Exchange (ETDEWEB)

    Espana, M. L.; Prieto, C.; Garcia, P.; Bejar, M. J.

    2011-07-01

    Ionizing radiation is nowadays widely used for both diagnosis and therapy mainly in nuclear medicine, diagnostic radiology and radiation oncology specialities. Benchmark techniques and advanced equipment like multislice CT in diagnostic radiology, PET-CT in nuclear medicine or IMRT or IGRT in radiotherapy are currently becoming regular in daily practice at hospitals. Medical exposures are by far the largest artificial source of public exposure to ionizing radiation. although concentrated in a relatively small percentage of the worlds population, these medical exposures continue to grow in a significant way, especially in developed countries. This fact makes it necessary to keep on working in radiological protection and safety at medical facilities. (Author) 11 refs.

  16. F--Ray: A new algorithm for efficient transport of ionizing radiation

    Science.gov (United States)

    Mao, Yi; Zhang, J.; Wandelt, B. D.; Shapiro, P. R.; Iliev, I. T.

    2014-04-01

    We present a new algorithm for the 3D transport of ionizing radiation, called F2-Ray (Fast Fourier Ray-tracing method). The transfer of ionizing radiation with long mean free path in diffuse intergalactic gas poses a special challenge to standard numerical methods which transport the radiation in position space. Standard methods usually trace each individual ray until it is fully absorbed by the intervening gas. If the mean free path is long, the computational cost and memory load are likely to be prohibitive. We have developed an algorithm that overcomes these limitations and is, therefore, significantly more efficient. The method calculates the transfer of radiation collectively, using the Fast Fourier Transform to convert radiation between position and Fourier spaces, so the computational cost will not increase with the number of ionizing sources. The method also automatically combines parallel rays with the same frequency at the same grid cell, thereby minimizing the memory requirement. The method is explicitly photon-conserving, i.e. the depletion of ionizing photons is guaranteed to equal the photoionizations they caused, and explicitly obeys the periodic boundary condition, i.e. the escape of ionizing photons from one side of a simulation volume is guaranteed to be compensated by emitting the same amount of photons into the volume through the opposite side. Together, these features make it possible to numerically simulate the transfer of ionizing photons more efficiently than previous methods. Since ionizing radiation such as the X-ray is responsible for heating the intergalactic gas when first stars and quasars form at high redshifts, our method can be applied to simulate thermal distribution, in addition to cosmic reionization, in three-dimensional inhomogeneous cosmological density field.

  17. An Ionizing Radiation Sensor Using a Pre-Programmed MAHAOS Device

    Directory of Open Access Journals (Sweden)

    Wen-Ching Hsieh

    2014-08-01

    Full Text Available Metal-aluminum oxide–hafnium aluminum oxide‒silicon oxide–silicon (hereafter MAHAOS devices can be candidates for ionizing radiation sensor applications. In this work, MAHAOS devices (SONOS-like structures with high k stack gate dielectric were studied regarding the first known characterization of the ionization radiation sensing response. The change of threshold voltage VT for a MAHAOS device after gamma ray exposure had a strong correlation to the total ionization dose (TID of gamma radiation up to at least 5 Mrad TID. In this paper, the gamma radiation response performances of the pre-programmed and virgin (non-pre-programmed MAHAOS devices are presented. The experimental data show that the change of VT for the pre-programmed MAHAOS device with gamma irradiation is very significant. The data of pre-programmed MAHAOS devices written by 5 Mrad TID of gamma radiation was also stable for a long time with data storage. The sensing of gamma radiation by pre-programmed MAHAOS devices with high k stack gate dielectric reported in this study has demonstrated their potential application for non-volatile ionizing radiation sensing technology in the future.

  18. Commentary: ethical issues of current health-protection policies on low-dose ionizing radiation.

    Science.gov (United States)

    Socol, Yehoshua; Dobrzyński, Ludwik; Doss, Mohan; Feinendegen, Ludwig E; Janiak, Marek K; Miller, Mark L; Sanders, Charles L; Scott, Bobby R; Ulsh, Brant; Vaiserman, Alexander

    2014-05-01

    The linear no-threshold (LNT) model of ionizing-radiation-induced cancer is based on the assumption that every radiation dose increment constitutes increased cancer risk for humans. The risk is hypothesized to increase linearly as the total dose increases. While this model is the basis for radiation safety regulations, its scientific validity has been questioned and debated for many decades. The recent memorandum of the International Commission on Radiological Protection admits that the LNT-model predictions at low doses are "speculative, unproven, undetectable and 'phantom'." Moreover, numerous experimental, ecological, and epidemiological studies show that low doses of sparsely-ionizing or sparsely-ionizing plus highly-ionizing radiation may be beneficial to human health (hormesis/adaptive response). The present LNT-model-based regulations impose excessive costs on the society. For example, the median-cost medical program is 5000 times more cost-efficient in saving lives than controlling radiation emissions. There are also lives lost: e.g., following Fukushima accident, more than 1000 disaster-related yet non-radiogenic premature deaths were officially registered among the population evacuated due to radiation concerns. Additional negative impacts of LNT-model-inspired radiophobia include: refusal of some patients to undergo potentially life-saving medical imaging; discouragement of the study of low-dose radiation therapies; motivation for radiological terrorism and promotion of nuclear proliferation.

  19. Stimulatory effects of low ionizing radiation on plant

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, S.; Kurisu, Y.; Murata, I.; Takahashi, A. [Department of Nuclear Engineering, Osaka Univ., Suita, Osaka (Japan); Masui, H.; Iida, T. [Department of Electronic, Information Systems and Energy Engineering, Osaka Univ., Suita, Osaka (Japan); Yamamoto, T. [Radioisotope Research Center, Osaka Univ., Suita, Osaka (Japan)

    2000-05-01

    Recently, the study for radiation hormesis was strongly carried out for animals and plants; subharmful dose of radiation may stimulate any organism. The concept of radiation hormesis effect consists of 1) biopositive effects of low dose radiation; influence caused by low dose radiation is totally different from one caused by high dose radiation, low dose radiation produces physiological useful effects against high dose radiation, and 2) radio-adaptive response; radiation also acts the organism as stress. Irradiated with small dose radiation previously, it raises its own defense response against the stress (radiation), resulting in the phenomenon that radiation influence decreases in appearance. In this paper we have investigated the phenomenon of radiation hormesis effects for plants through irradiation experiments with neutrons and gamma-rays to find out the mechanism. In the present experiment, dry seeds of Raphanus sativus were irradiated with D-T neutrons (10 {mu}Gy {approx} 100 kGy), D-D neutrons (1 mGy {approx} 100 mGy), thermal and fast neutrons (irradiation in a nuclear reactor: 100 {mu}Gy {approx} 10 Gy), 60Co gamma-rays (10 {mu}Gy {approx} 10 Gy). To confirm existence of the radiation hormesis effects, germination percentage, length of hypocotyl, length of root and total weight of seed leaf were measured at 7th day after starting cultivation. We estimated relative effectiveness as the hormesis effect, that is the ratio of mean values of measured subjects for the irradiated and control groups. For Raphanus sativus, the hormesis effect on seed leaf growth has been observed in the seed group irradiated by D-T neutrons and D-D neutrons. The observed hormesis effect is from 5 to 25 percents. (author)

  20. Ionizing radiation treatment to improve postharvest life and maintain quality of fresh guava fruit

    Science.gov (United States)

    Singh, S. P.; Pal, R. K.

    2009-02-01

    We investigated the potential of ionizing radiation for improving physiological responses, quality, and storage time of fresh guava fruit. Ionizing radiation treatment suppressed the respiration and ethylene production rates and thus retarded the process of fruit ripening during storage. Irradiation treatment also retarded the physical and biochemical changes associated with ripening such as firmness, titratable acidity, soluble solids content, and vitamin C during storage, but for doses higher than 0.25 kGy the vitamin C content decreased. The positive effects of ionizing radiation treatment on delayed fruit ripening and other quality attributes diminished during 22 days of storage at 10 °C. Thus, a combination of ionizing radiation with low-temperature storage (10 °C) did not have much synergistic effect on storage life and quality of guava fruit. In conclusion, ionizing radiation treatment of guava fruit with 0.25 kGy dose increased the postharvest life by 3-4 days, maintained fruit quality, and reduced the decay incidence. The optimal dose (0.25 kGy) for postharvest life extension of guava fruit may be exploited to provide phytosanitary security against many insect pests including fruit flies.

  1. Ionizing radiation treatment to improve postharvest life and maintain quality of fresh guava fruit

    Energy Technology Data Exchange (ETDEWEB)

    Singh, S.P. [Handling and Storage Laboratory, Division of Postharvest Technology, Indian Agricultural Research Institute (IARI), Pusa, New Delhi 110 012 (India)], E-mail: sukhvinder.singh@curtin.edu.au; Pal, R.K. [Handling and Storage Laboratory, Division of Postharvest Technology, Indian Agricultural Research Institute (IARI), Pusa, New Delhi 110 012 (India)

    2009-02-15

    We investigated the potential of ionizing radiation for improving physiological responses, quality, and storage time of fresh guava fruit. Ionizing radiation treatment suppressed the respiration and ethylene production rates and thus retarded the process of fruit ripening during storage. Irradiation treatment also retarded the physical and biochemical changes associated with ripening such as firmness, titratable acidity, soluble solids content, and vitamin C during storage, but for doses higher than 0.25 kGy the vitamin C content decreased. The positive effects of ionizing radiation treatment on delayed fruit ripening and other quality attributes diminished during 22 days of storage at 10 deg. C. Thus, a combination of ionizing radiation with low-temperature storage (10 deg. C) did not have much synergistic effect on storage life and quality of guava fruit. In conclusion, ionizing radiation treatment of guava fruit with 0.25 kGy dose increased the postharvest life by 3-4 days, maintained fruit quality, and reduced the decay incidence. The optimal dose (0.25 kGy) for postharvest life extension of guava fruit may be exploited to provide phytosanitary security against many insect pests including fruit flies.

  2. Study of the ionizing radiation effects on the swedish telecommunications network. Studie av telekommunikationernas talighet mot joniserande stralning

    Energy Technology Data Exchange (ETDEWEB)

    Goeransson, G.; Liljegren, T.

    1992-11-01

    The aim of the study is to form a basis for decisions on possible protective measures concerning the ionizing radiation effects on the Swedish telecommunications from nuclear weapon explosions outside Sweden. The report contains a brief survey of analysis and the experimental investigations of the ionizing radiation effects on optical fibers, repeaters and microwave radio-link equipments. It also deals with the Swedish Telecommunication Network buildings and their ionizing radiation protection as well as with some specially selected telecommunication objects.

  3. Adaptation of the black yeast Wangiella dermatitidis to ionizing radiation: molecular and cellular mechanisms.

    Directory of Open Access Journals (Sweden)

    Kelly L Robertson

    Full Text Available Observations of enhanced growth of melanized fungi under low-dose ionizing radiation in the laboratory and in the damaged Chernobyl nuclear reactor suggest they have adapted the ability to survive or even benefit from exposure to ionizing radiation. However, the cellular and molecular mechanism of fungal responses to such radiation remains poorly understood. Using the black yeast Wangiella dermatitidis as a model, we confirmed that ionizing radiation enhanced cell growth by increasing cell division and cell size. Using RNA-seq technology, we compared the transcriptomic profiles of the wild type and the melanin-deficient wdpks1 mutant under irradiation and non-irradiation conditions. It was found that more than 3000 genes were differentially expressed when these two strains were constantly exposed to a low dose of ionizing radiation and that half were regulated at least two fold in either direction. Functional analysis indicated that many genes for amino acid and carbohydrate metabolism and cell cycle progression were down-regulated and that a number of antioxidant genes and genes affecting membrane fluidity were up-regulated in both irradiated strains. However, the expression of ribosomal biogenesis genes was significantly up-regulated in the irradiated wild-type strain but not in the irradiated wdpks1 mutant, implying that melanin might help to contribute radiation energy for protein translation. Furthermore, we demonstrated that long-term exposure to low doses of radiation significantly increased survivability of both the wild-type and the wdpks1 mutant, which was correlated with reduced levels of reactive oxygen species (ROS, increased production of carotenoid and induced expression of genes encoding translesion DNA synthesis. Our results represent the first functional genomic study of how melanized fungal cells respond to low dose ionizing radiation and provide clues for the identification of biological processes, molecular pathways and

  4. Radiation pressure confinement - III. The origin of the broad ionization distribution in AGN outflows

    Science.gov (United States)

    Stern, Jonathan; Behar, Ehud; Laor, Ari; Baskin, Alexei; Holczer, Tomer

    2014-12-01

    The winds of ionized gas driven by active galactic nuclei (AGN) can be studied through absorption lines in their X-ray spectra. A recurring feature of these outflows is their broad ionization distribution, including essentially all ionization levels (e.g., Fe0+ to Fe25+). This characteristic feature can be quantified with the absorption measure distribution (AMD), defined as the distribution of column density with ionization parameter |dN/d log ξ|. Observed AMDs extend over 0.1 ≲ ξ ≲ 104 (cgs), and are remarkably similar in different objects. Power-law fits (|dN/d log ξ| ≈ N1ξa) yield N1 = 3 × 1021 cm- 2 ± 0.4 dex and a = 0-0.4. What is the source of this broad ionization distribution, and what sets the small range of observed N1 and a? A common interpretation is a multiphase outflow, with a wide range of gas densities in a uniform gas pressure medium. However, the incident radiation pressure leads to a gas pressure gradient in the photoionized gas, and therefore to a broad range of ionization states within a single slab. We show that this compression of the gas by the radiation pressure leads to an AMD with |dN/d log ξ| = 8 × 1021 ξ0.03 cm-2, remarkably similar to that observed. The calculated values of N1 and a depend weakly on the gas metallicity, the ionizing spectral slope, the distance from the nucleus, the ambient density, and the total absorber column. Thus, radiation pressure compression (RPC) of the photoionized gas provides a natural explanation for the observed AMD. RPC predicts that the gas pressure increases with decreasing ionization, which can be used to test the validity of RPC in ionized AGN outflows.

  5. Measurement of the track structure of ionizing radiation; Messung der Spurstruktur ionisierender Strahlung

    Energy Technology Data Exchange (ETDEWEB)

    Hilgers, Gerhard [Physikalisch-Technische Bundesanstalt (PTB), Braunschweig (Germany). Arbeitsgruppe ' Nanodosimetrie'

    2013-06-15

    After a description of the nanodosimetric measurement quantities of tracks induced by ionizing radiation the nanodosemeter operated in the PTB is described. Finally the scaling behaviour of nanodosimetry is considered. In order to test the validity of the corresponding equation ionization-cluster size distributions were measured with monoenergetic proton and alpha beams in the energy range from 0.1 to 20 MeV with propane and nitrogen as measuring gases. (HSI)

  6. Effects of ionizing radiations on in utero development

    Energy Technology Data Exchange (ETDEWEB)

    Lallemand, J. (EdF, 75 - Paris (France))

    1984-01-01

    Following a reminder of embryology and methodology, a review is made of the main teratogenic effects related to radiation exposure, i.e. lethal effects, radioinduced malformations, maldevelopment and cancers. The sensitivity of the embryo and foetus to radiation seems to last during the whole gestation. Howewer, the latest investigations indicate that the main damage is mental retardation. This review concludes on practical considerations of radiation protection in the field of radiographic examinations of pregnant women.

  7. Mechanisms of alteration of the immune system by ionizing radiations: a basis for radiation protection

    Energy Technology Data Exchange (ETDEWEB)

    Bourguignon, M. [Direction Generale de la Surete Nucleaire et de la Radioprotection, 75 - Paris (France); Perez, M.; Dubner, D.; Michelin, S. [Autoridad Regulatoria Nuclear, Buenos Aires (Argentina); Carosella, E. [CEA, Service de Recherches en Hemato -Immunologie, 75 - Paris (France)

    2006-07-01

    Full text of publication follows: Alterations of the immune system appear in relationship with exposure to ionizing radiation (IR) in different situations, e.g., accidents, radiation therapy of cancer, prenatal irradiation, some human diseases with hypersensitivity to IR and aging. Thus, the comprehension of the mechanisms of the alterations of the immune system by IR is necessary to elaborate strategies of protection and to pave the way for future possible therapies. At least 9 mechanisms of alterations can be identified: 1- Apoptosis. Apoptosis is a key mechanism of the natural regulation of the immune system and plays also a key role in the response to IR: lymphocytes die rapidly by apoptosis after exposure. Different pathways of induction of apoptosis have been identified, and include p53 dependent and mitochondria mediated pathways, as well as CD95 and ROS initiation; 2- TCR mutations. The T cell antigen receptor is responsible to discriminate between self and non self. Mutations of the TCR may result from exposure to IR; 3- Modification of the Th1-Th2 balance. T helper cells may express 2 distinct secretion patterns: Th1 cytokines promote cell-mediated immunity while Th2 cytokines favor humoral immunity. Although the effects of IR on the Th1/Th2 balance remains controversial, an imbalance towards a Th2 profile is likely and patients with cancer and systemic auto-immune disease often present a switch from Th1 to Th2; 4- Bystander effects and genetic instability. Stimulatory effect or genomic instability have been observed in haematopoietic cells exposed to IR and related to a bystander mechanism. 5- Shift toward an inflammatory profile. Ionizing radiation may induce a persistent inflammatory profile as a result of dis-regulation of cytokine production; such a status of persistent inflammation has been observed in Hiroshima and Nagasaki survivors. 6- Modification of antigen presentation. Antigen presentation by dendritic cells is an essential function preceding

  8. Adaptive response in frogs chronically exposed to low doses of ionizing radiation in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Audette-Stuart, M., E-mail: stuartm@aecl.ca [Environmental Technologies Branch, Atomic Energy of Canada Limited, Chalk River Laboratories, Chalk River, Ontario, K0J 1P0 (Canada); Kim, S.B.; McMullin, D.; Festarini, A.; Yankovich, T.L.; Carr, J.; Mulpuru, S. [Environmental Technologies Branch, Atomic Energy of Canada Limited, Chalk River Laboratories, Chalk River, Ontario, K0J 1P0 (Canada)

    2011-06-15

    Using the micronucleus assay, decreased levels of DNA damage were found after high dose ionizing radiation exposure of liver cells taken from frogs inhabiting a natural environment with above-background levels of ionizing radiation, compared to cells taken from frogs inhabiting background areas. The data obtained from a small number of animals suggest that stress present in the above-background environment could induce an adaptive response to ionizing radiation. This study did not reveal harmful effects of exposure to low levels of radioactivity. On the contrary, stress present in the above-background area may serve to enhance cellular defense mechanisms. - Highlights: > Frogs were collected from background and higher tritium level habitats. > The micronucleus assay was conducted on liver cells obtained from the frogs. > No detrimental effects were noted in frogs exposed to elevated tritium. > Adaptive responses were observed in frogs exposed to elevated tritium.

  9. Production of foil electrets by ionizing radiation in air

    Science.gov (United States)

    Fallone, B. G.; Podgorsak, E. B.

    1983-02-01

    Isothermal charge deposition on polymers to form stable foil electrets by using apparatuses resembling parallel-plate ionization chambers is reported. Charge carriers produced by irradiation of the sensitive chamber air volume drift in an externally applied electric field and get trapped on the polymer surface to form electrets with maximum charge densities close to 10-6 C/cm2. Charge density as a function of applied voltage follows the form typical of a Schottky or Poole-Frenkel process.

  10. Dissecting plant chromosomes by the use of ionizing radiation

    Science.gov (United States)

    Radiation treatment of genomes is used to generate chromosome breaks for numerous applications. This protocol describes the preparation of seeds and the determination of the optimal level of irradiation dosage for the creation of a radiation hybrid (RH) population. These RH lines can be used to gene...

  11. Effect of Ionizing Beta Radiation on the Mechanical Properties of Poly(ethylene under Thermal Stress

    Directory of Open Access Journals (Sweden)

    Bednarik Martin

    2016-01-01

    Full Text Available It was found in this study, that ionizing beta radiation has a positive effect on the mechanical properties of poly(ethylene. In recent years, there have been increasing requirements for quality and cost effectiveness of manufactured products in all areas of industrial production. These requirements are best met with the polymeric materials, which have many advantages in comparison to traditional materials. The main advantages of polymer materials are especially in their ease of processability, availability, and price of the raw materials. Radiation crosslinking is one of the ways to give the conventional plastics mechanical, thermal, and chemical properties of expensive and highly resistant construction polymers. Several types of ionizing radiation are used for crosslinking of polymers. Each of them has special characteristics. Electron beta and photon gamma radiation are used the most frequently. The great advantage is that the crosslinking occurs after the manufacturing process at normal temperature and pressure. The main purpose of this paper has been to determine the effect of ionizing beta radiation on the tensile modulus, strength and elongation of low and high density polyethylene (LDPE and HDPE. These properties were examined in dependence on the dosage of the ionizing beta radiation (non-irradiated samples and those irradiated by dosage 99 kGy were compared and on the test temperature. Radiation cross-linking of LDPE and HDPE results in increased tensile strength and modulus, and decreased of elongation. The measured results indicate that ionizing beta radiation treatment is effective tool for improvement of mechanical properties of LDPE and HDPE under thermal stress.

  12. The biobehavioral and neuroimmune impact of low-dose ionizing radiation

    Science.gov (United States)

    York, Jason M; Blevins, Neil A; Meling, Daryl D; Peterlin, Molly B; Gridley, Daila S; Cengel, Keith A; Freund, Gregory G

    2011-01-01

    In the clinical setting, repeated exposures (10–30) to low-doses of ionizing radiation (≤ 200 cGy), as seen in radiotherapy for cancer, causes fatigue. Almost nothing is known, however, about the fatigue inducing effects of a single exposure to environmental low-dose ionizing radiation that might occur during high-altitude commercial air flight, a nuclear reactor accident or a solar particle event (SPE). To investigate the short-term impact of low-dose ionizing radiation on mouse biobehaviors and neuroimmunity, male CD-1 mice were whole body irradiated with 50 cGy or 200 cGy of gamma or proton radiation. Gamma radiation was found to reduce spontaneous locomotor activity by 35% and 36%, respectively, 6 h post irradiation. In contrast, the motivated behavior of social exploration was un-impacted by gamma radiation. Examination of pro-inflammatory cytokine gene transcripts in the brain demonstrated that gamma radiation increased hippocampal TNF-α expression as early as 4 h post-irradiation. This was coupled to subsequent increases in IL-1RA (8 h and 12 h post irradiation) in the cortex and hippocampus and reductions in activity-regulated cytoskeleton-associated protein (Arc) (24 h post irradiation) in the cortex. Finally, restraint stress was a significant modulator of the neuroimmune response to radiation blocking the ability of 200 cGy gamma radiation from impairing locomotor activity and altering the brain-based inflammatory response to irradiation. Taken together, these findings indicate that low-dose ionizing radiation rapidly activates the neuroimmune system potentially causing early onset fatigue-like symptoms in mice. PMID:21958477

  13. Genetic effects in somatic and germ cells, induced by ionizing radiations

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, B.; Benova, D.; Bajrakova, A.; Bulanova, M.; Vyglenov, A.; Rupova, I.; Georgieva, I. (Meditsinska Akademiya, Sofia (Bulgaria). Nauchen Inst. po Rentgenologiya i Radiobiologiya)

    1983-01-01

    Quantitative data are reported on injuries to hereditary structures in somatic and sex cells, induced by different types of ionizing radiation. The model systems used were human peripheral blood lymphocytes, in vitro irradiated with different doses: bone-marrow cells of mice and rats irradiated in vivo: mouse, rat, rabbit and hamster sex cells. To evaluate the dose-effect dependency after acute and chronic irradiation, the authors used mathematical models, describing the amount of chromosomal injuries. Attempt was made to estimate the somatic and genetic risk, following acute and chronic irradiation with different doses of ionizing radiations.

  14. Performance of a parallel plate ionization chamber in beta radiation dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Antonio, Patricia L.; Caldas, Linda V.E., E-mail: patrilan@ipen.b, E-mail: lcaldas@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    A homemade parallel plate ionization chamber with graphite collecting electrode, and developed for use in mammography beams, was tested in relation to its usefulness in beta radiation dosimetry at the Calibration Laboratory of IPEN. Characterization tests of this ionization chamber were performed, using the Sr-90 + Y-90, Kr-85 and Pm-147 sources of a beta secondary standard system. The results of saturation, leakage current, stabilization time, response stability, linearity, angular dependence, and calibration coefficients are within the recommended limits of international recommendations that indicate that this chamber may be used for beta radiation dosimetry. (author)

  15. Ionizing and Non-ionizing Radiation Effects in Thin Layer Hexagonal Boron Nitride

    Science.gov (United States)

    2015-03-01

    performance of electronic devices and systems that must operate in a radiation harsh environment. Graphene is an emerging two dimensional (2D) material for... graphene -based electronic systems because it has the same lattice structure as graphene , is an insulator, and is known to form on graphene surfaces. h...BN also has superior material and electrical properties as compared to insulators such as SiO2 or Al2O3. Understanding the effects of radiation on h

  16. Ionizing radiations in pregnancy and teratogenesis: a review of literature.

    Science.gov (United States)

    De Santis, M; Di Gianantonio, E; Straface, G; Cavaliere, A F; Caruso, A; Schiavon, F; Berletti, R; Clementi, M

    2005-01-01

    The present paper is a review of the data available in the literature concerning the prenatal exposure to radiation evaluating the reported teratogenic effect. We have particularly focused on the fetal effects of maternal ionising radiation exposure, both diagnostic and occupational, particularly in terms of congenital anomalies and birth weight. Ionising radiation represents a possible teratogen for the fetus, but this risk has been found to be dependent on the dosage and the effects correlatable to the gestational age at exposure. Recently, of particularly note is the fact that maternal thyroid exposure to diagnostic radiation has been associated with a slight reduction in the birth weight. Inadvertent exposure from diagnostic procedures in pregnancy doesn't usually increase the natural risk of congenital anomalies but creates a considerable state of maternal anxiety. Diagnostic radiological procedures should be avoided in pregnant women unless the information cannot be obtained by other techniques.

  17. [Thoughts on carcinogenic pollution caused by ionizing radiation].

    Science.gov (United States)

    Latarjet, R

    1976-01-01

    The pollution phenomenon groups the effects of small doses of radiation on large populations. These effects on Man are not directly accessible. One must: a) consider some epidemiological statistics (cosmic radiation at high altitudes; radioactivity from granitic surroundings); b) extrapolate from datas obtained with high doses; c) extrapolate from datas obtained with low doses in micro-organisms or mammalian cells in vitro. The interpolation scheme of Abrahamson et al. is so available for mutagenicity. The question of a threshold remains theoretical, although radiation-induced carcinogenesis often displays a dose-effects curve with a well market threshold. A new concept, that of a "practical threshold" is developped, which may be of great usefulness. The main genetic considerations are listed upon which the present international admissible doses are based. Finally, in order to establish quantitative comparisons between chemical and radiation carcinogenic pollution, the concept of "rad equivalents" for the main chemical mutagens is stressed.

  18. Procedure to evaluate the ionizing radiation influence over LED and magnetic induction lamps

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Otavio Luis de; Menzel, Silvio Carlos, E-mail: otavioluis@ipen.br, E-mail: scmenzel@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (CEN/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Engenharia Nuclear; Ribas, Jacinto Oliveira, E-mail: jacinto@eletronuclear.gov.br [Eletrobras Termonuclear S.A. (ELETRONUCLEAR), Angra dos Reis, RJ (Brazil). Gerencia de Eletrica e Instrumentacao

    2015-07-01

    The goal of this paper is to present a methodology to evaluate the ionizing radiation influence over Lighting Emitting Diode (LED) and Magnetic Induction (MI) lamps as they use a lot of electronic in their power supply. Considering they have a huge lifetime it is interesting to apply this technology into environments under ionizing radiation, such as a nuclear facility. Thus, it is possible to increase the period between two consecutive maintenance, reduce the repair and global maintenance costs and reduce the operational personnel exposure to ionizing radiation. In this context it is going to be presented a scheme to select different LED and MI lamps available in the Brazilian market, a methodology to irradiate several lamp samples according various radiation levels that can be found in the facilities and the electrical and photometric evaluation to be performed. Considering this methodology it will be possible to analyze the lamps capacity to withstand ionizing radiation, under regular operating conditions of the facilities and its effects in the performance and lifetime of the selected lamps. Thus, the procedures suggested in this work can be used as a guide to perform experiments and analysis to find specific lamps that can reduce the global maintenance costs and the personnel exposure. Hereafter, several lamps are going to be acquired and the tests performed, according the procedures here described. (author)

  19. Astrophysical radiative neutron capture on 10B taking into account resonance at 475 keV

    CERN Document Server

    Dubovichenko, Sergey

    2013-01-01

    The possibility of the description of the available experimental data for cross sections of the neutron capture reaction on 10B at thermal and astrophysical energies, taking into account the resonance at 475 keV, was considered within the framework of the modified potential cluster model with forbidden states and accounting for the resonance behavior of the scattering phase shifts.

  20. Effect of Ionizing Radiation on the Properties of Porous Silicon Nanostructures

    Directory of Open Access Journals (Sweden)

    I.B. Olenych

    2015-12-01

    Full Text Available The influence of ionizing radiation from 226Ra source on the electrical and photoluminescent properties of porous silicon nanostructures was investigated. After the radiation exposure, AC resistance of experimental samples decreased and luminescence band was changed. Temperature dependencies of electrical conductivity and depolarization current were studied in 80-325 K temperature range. Effect of radiation on the energy distribution of localized electronic states in porous silicon based structures is analyzed. Obtained results expand the application prospective of porous silicon for radiation sensing.

  1. The protective effects of trace elements against side effects induced by ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hosseinimehr, Seyed Jaial [Dept. of Radiopharmacy, Faculty of Pharmacy, Pharmaceutical Sciences Research Center, Mazandaran University of Medical Sciences, Sari (Iran, Islamic Republic of)

    2015-06-15

    Trace elements play crucial role in the maintenance of genome stability in the cells. Many endogenous defense enzymes are containing trace elements such as superoxide dismutase and metalloproteins. These enzymes are contributing in the detoxification of reactive oxidative species (ROS) induced by ionizing radiation in the cells. Zinc, copper, manganese, and selenium are main trace elements that have protective roles against radiation-induced DNA damages. Trace elements in the free salt forms have protective effect against cell toxicity induced by oxidative stress, metal-complex are more active in the attenuation of ROS particularly through superoxide dismutase mimetic activity. Manganese-complexes in protection of normal cell against radiation without any protective effect on cancer cells are more interesting compounds in this topic. The aim of this paper to review the role of trace elements in protection cells against genotoxicity and side effects induced by ionizing radiation.

  2. The Origin and Optical Depth of Ionizing Radiation in the "Green Pea" Galaxies

    CERN Document Server

    Jaskot, A E

    2013-01-01

    Although Lyman continuum (LyC) radiation from star-forming galaxies likely drove the reionization of the Universe, observations of star-forming galaxies at low redshift generally indicate low LyC escape fractions. However, the extreme [O III]/[O II] ratios of the z=0.1-0.3 Green Pea galaxies may be due to high escape fractions of ionizing radiation. To analyze the LyC optical depths and ionizing sources of these rare, compact starbursts, we compare nebular photoionization and stellar population models with observed emission lines in the Peas' SDSS spectra. We focus on the six most extreme Green Peas, the galaxies with the highest [O III]/[O II] ratios and the best candidates for escaping ionizing radiation. The Balmer line equivalent widths and He I {\\lambda}3819 emission in the extreme Peas support young ages of 3-5 Myr, and He II {\\lambda}4686 emission in five extreme Peas signals the presence of hard ionizing sources. Ionization by active galactic nuclei or high-mass X-ray binaries is inconsistent with the...

  3. Ionizing Radiation Induces HMGB1 Cytoplasmic Translocation and Extracellular Release

    Institute of Scientific and Technical Information of China (English)

    Lili Wang; Li He; Guoqiang Bao; Xin He; Saijun Fan; Haichao Wang

    2016-01-01

    Objective A nucleosomal protein,HMGBI,can be secreted by activated immune cells or passively released by dying cells,thereby amplifying rigorous inflammatory responses.In this study we aimed to test the possibility that radiation similarly induces cytoplasmic HMGB1 translocation and release.Methods Human skin fibroblast (GM0639) and bronchial epithelial (16HBE) cells and rats were exposed to X-ray radiation,and HMGB1 translocation and release were then assessed by immunocytochemistry and immunoassay,respectively.Results At a wide dose range(4.0-12.0 Gy),X-ray radiation induced a dramatic cytoplasmic HMGB1 translocation,and triggered a time-and dose-dependent HMGB1 release both in vitro and in vivo.The radiation-mediated HMGB1 release was also associated with noticeable chromosomal DNA damage and loss of cell viability.Conclusions Radiation induces HMGB1 cytoplasmic translocation and extracellular release through active secretion and passive leakage processes.

  4. Ionizing Radiation Promotes the Migratory and Invasive Potential of Lung Cancer Cells by Different Mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Jin Nyoung; Kang, Ga Young; Um, Hong Duck [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2008-05-15

    Although radiation therapy is a major therapeutic modality for cancer treatment, previous reports have suggested that ionizing radiation (IR) can promote the invasive and metastatic potential of cancer cells. It was consistently reported that IR can induce certain types of matrix metalloproteinases, which are critical to the degradation of extracellular matrix. Given that the motility of cancer cells is an additional requirement for their metastasis, this study investigated whether IR can also influence the migratory potential of cancer cells.

  5. 21 CFR 579.40 - Ionizing radiation for the treatment of poultry feed and poultry feed ingredients.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ionizing radiation for the treatment of poultry feed and poultry feed ingredients. 579.40 Section 579.40 Food and Drugs FOOD AND DRUG ADMINISTRATION... § 579.40 Ionizing radiation for the treatment of poultry feed and poultry feed ingredients....

  6. Application of ionizing radiation in sterilization of Selasan milk replacer

    Energy Technology Data Exchange (ETDEWEB)

    Olbrichova, D.; Zouharova, A.; Buriankova, E. (Statni Vyzkumny Ustav Textilni, Veverska Bityska (Czechoslovakia). Centrum Radiacnich Technologii)

    1984-08-01

    The effect of eight ascending doses of radiation within the range of 3 to 30 kGy on isolated microflora was observed in the milk replacer Selasan with initial contamination 4.9x10/sup 4/ germs per 1 gram of preparation. Microorganisms which survived the said radiation dose were evaluated micro and macroscopically. The level of resistance of isolates was determined on the basis of parameters of inactivation curves Nsub(D)=N/sub 0/.esup(-kD). The obtained data served as the basis for determining the minimum sterilization dose 25 kGy for the Selasan replacer.

  7. A Novel Highly Ionizing Particle Trigger using the ATLAS Transition Radiation Tracker

    CERN Document Server

    Penwell, J; The ATLAS collaboration

    2011-01-01

    The ATLAS Transition Radiation Tracker (TRT) is an important part of the experiment’s charged particle tracking system. It also provides the ability to discriminate electrons from pions efficiently using large signal amplitudes induced in the TRT straw tubes by transition radiation. This amplitude information can also be used to identify heavily ionizing particles, such as monopoles, or Q-balls, that traverse the straws. Because of their large ionization losses, these particles can range out before they reach the ATLAS calorimeter, making them difficult to identify by the experiment’s first level trigger. Much of this inefficiency could be regained by making use of a feature of the TRT electronics that allows fast access to information on whether large-amplitude signals were produced in regions of the detector. A modest upgrade to existing electronics could allow triggers sensitive to heavily ionizing particles at level-1 to be constructed by counting such large-amplitude signals in roads corresponding to...

  8. Detailed Investigations of Interactions between Ionizing Radiation and Neutral Gases

    Energy Technology Data Exchange (ETDEWEB)

    Landers, Allen L

    2014-03-31

    We are investigating phenomena that stem from the many body dynamics associated with ionization of an atom or molecule by photon or charged particle. Our program is funded through the Department of Energy EPSCoR Laboratory Partnership Award in collaboration with Lawrence Berkeley National Laboratory. We are using variations on the well established COLTRIMS technique to measure ions and electrons ejected during these interactions. Photoionization measurements take place at the Advanced Light Source at LBNL as part of the ALS-COLTRIMS collaboration with the groups of Reinhard Dörner at Frankfurt and Ali Belkacem at LBNL. Additional experiments on charged particle impact are conducted locally at Auburn University where we are studying the dissociative molecular dynamics following interactions with either ions or electrons over a velocity range of 1 to 12 atomic units.

  9. Ionizing Radiation Impacts on Cardiac Differentiation of Mouse Embryonic Stem Cells

    Science.gov (United States)

    Helm, Alexander; Arrizabalaga, Onetsine; Pignalosa, Diana; Schroeder, Insa S.; Durante, Marco

    2016-01-01

    Little is known about the effects of ionizing radiation on the earliest stages of embryonic development although it is well recognized that ionizing radiation is a natural part of our environment and further exposure may occur due to medical applications. The current study addresses this issue using D3 mouse embryonic stem cells as a model system. Cells were irradiated with either X-rays or carbon ions representing sparsely and densely ionizing radiation and their effect on the differentiation of D3 cells into spontaneously contracting cardiomyocytes through embryoid body (EB) formation was measured. This study is the first to demonstrate that ionizing radiation impairs the formation of beating cardiomyocytes with carbon ions being more detrimental than X-rays. However, after prolonged culture time, the number of beating EBs derived from carbon ion irradiated cells almost reached control levels indicating that the surviving cells are still capable of developing along the cardiac lineage although with considerable delay. Reduced EB size, failure to downregulate pluripotency markers, and impaired expression of cardiac markers were identified as the cause of compromised cardiomyocyte formation. Dysregulation of cardiac differentiation was accompanied by alterations in the expression of endodermal and ectodermal markers that were more severe after carbon ion irradiation than after exposure to X-rays. In conclusion, our data show that carbon ion irradiation profoundly affects differentiation and thus may pose a higher risk to the early embryo than X-rays. PMID:26506910

  10. Studying the Effect of Ionization Radiation of 60Co on the Spirulina

    Science.gov (United States)

    Ai, Weidang; Guo, Shuang-Sheng; Ai, Weidang; Dong, Wen-Ping; Qin, Li-Feng; Tang, Yong-Kang

    It studied the effect of ionization radiation on the Spirulina plastensis(No.6) by using the γ-rays of 60 Co. In the experiment, Spirulina were irradiated, and the dose of the ionization radiation covered 0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0kGy. After irradiating, these Spirulina were cultured under the same conditions. During the course of the experiment, the growth rate, photosynthetic efficiency and nutrition quality of the Spirulina, were analyzed. From the results, low dose of γ-rays (less than 1.5kGy) could improve the content of phycobilin and protein of Spirulina. Only small changes in the morphology of algae filament were found at dose less than 1.0kGy. But with the increase of the dose of γ-rays (more than 1.5kGy), the filaments would break up or even disintegrate. Spirulina had stronger ionization radiation proof and self-rehabilitation capacity, but the growth of Spirulina was stagnated. The LD50 (i.e. the dose resulted in 50% death of the Spirulina) of the colony was 2.0kGy. Considering the capacity of being resistant to γ-rays irradiation, Spirulina can be considered as one of the key biological components in the Controlled Ecological Life Support System (CELSS) for future long-term space missions. Keywords: Controlled Ecological Life Support System (CELSS); Spirulina; ionization radiation; biological component

  11. The Escape of Ionizing Photons from OB Associations in Disk Galaxies Radiation Transfer Through Superbubbles

    CERN Document Server

    Dove, J B; Ferrara, A; Dove, James B.; Ferrara, Andrea

    1999-01-01

    By solving the time-dependent radiation transfer problem of stellar radiation through evolving superbubbles within a smoothly varying H I distribution, we have estimated the fraction of ionizing photons emitted by OB associations that escapes the H I disk of our Galaxy. We considered a coeval star-formation history and a Gaussian star-formation history with a time spread sigma_t = 2 Myr. We find that the shells of the expanding superbubbles quickly trap or attenuate the ionizing flux, such that most of the escaping radiation escapes shortly after the formation of the superbubble. Superbubbles of large associations can blowout of the H I disk and form dynamic chimneys, which allow the ionizing radiation directly to escape the H I disk. However, blowout occurs when the ionizing photon luminosity has dropped well below the association's maximum luminosity. For the coeval star-formation history, the fraction of photons that escape each side of the disk in the solar vicinity is f_esc approx 6% (the total fraction ...

  12. Possible standoff detection of ionizing radiation using high-power THz electromagnetic waves

    Science.gov (United States)

    Nusinovich, Gregory S.; Sprangle, Phillip; Romero-Talamas, Carlos A.; Rodgers, John; Pu, Ruifeng; Kashyn, Dmytro G.; Antonsen, Thomas M., Jr.; Granatstein, Victor L.

    2012-06-01

    Recently, a new method of remote detection of concealed radioactive materials was proposed. This method is based on focusing high-power short wavelength electromagnetic radiation in a small volume where the wave electric field exceeds the breakdown threshold. In the presence of free electrons caused by ionizing radiation, in this volume an avalanche discharge can then be initiated. When the wavelength is short enough, the probability of having even one free electron in this small volume in the absence of additional sources of ionization is low. Hence, a high breakdown rate will indicate that in the vicinity of this volume there are some materials causing ionization of air. To prove this concept a 0.67 THz gyrotron delivering 200-300 kW power in 10 microsecond pulses is under development. This method of standoff detection of concealed sources of ionizing radiation requires a wide range of studies, viz., evaluation of possible range, THz power and pulse duration, production of free electrons in air by gamma rays penetrating through container walls, statistical delay time in initiation of the breakdown in the case of low electron density, temporal evolution of plasma structure in the breakdown and scattering of THz radiation from small plasma objects. Most of these issues are discussed in the paper.

  13. Identifying the Proteins that Mediate the Ionizing Radiation Resistance of Deinococcus Radiodurans R1

    Energy Technology Data Exchange (ETDEWEB)

    Battista, John R

    2010-02-22

    The primary objectives of this proposal was to define the subset of proteins required for the ionizing radiation (IR) resistance of Deinococcus radiodurans R1, characterize the activities of those proteins, and apply what was learned to problems of interest to the Department of Energy.

  14. Inactivation by ionizing radiation of Salmonella enteritidis serotype montevideo grown in composed sewage sludge

    Energy Technology Data Exchange (ETDEWEB)

    Brandon, J.R.; Burge, W.D.; Enkiri, N.K.

    1977-04-01

    S. enteritidis ser. montevideo were grown in composted sewage sludge to levels of approximately 10/sup 9//g. These bacteria were found to be inactivated by ionizing radiation (with Co/sub 60/) at approximately the same rate (30 krads/log) as Salmonella species in liquid digested sludge.

  15. Combined effect of heptaplatin and ionizing radiation on human squamous carcinoma cell lines.

    Science.gov (United States)

    Ryu, Mi-Ryeong; Paik, Soon-Young; Chung, Su-Mi

    2005-02-28

    Heptaplatin, cis-malonato [(4R,5R)-4,5-bis (amino-methyl)-2-isopropyl-1,3-dioxolane] platinum(II) (SKI-2053R, Sunpla) is a new platinum derivative with anti-tumor activity comparable to cisplatin on various cancer cell lines. Preclinical studies suggest that it is less nephrotoxic than cisplatin. This study was undertaken to examine the combined effect of heptaplatin and ionizing radiation on two established human squamous carcinoma cell lines (NCI-H520, SQ20B). The cytotoxic activity of heptaplatin was concentration-dependent in both cell lines. When low dose heptaplatin was combined with high dose ionizing radiation, there was an additive cytotoxic effect on NCI-H520 cells (P < 0.05), while a moderate dose of heptaplatin and a low dose of ionizing radiation had an additive cytotoxic effect on the growth of SQ20B cells (P < 0.05). FACS analysis and DAPI staining showed that their additive cytotoxic effects were correlated with the induction of apoptosis. Further studies are warranted using heptaplatin and ionizing radiation in squamous cell carcinoma as a substitute for cisplatin.

  16. Mammalian Tissue Response to Low Dose Ionizing Radiation: The Role of Oxidative Metabolism and Intercellular Communication

    Energy Technology Data Exchange (ETDEWEB)

    Azzam, Edouard I

    2013-01-16

    The objective of the project was to elucidate the mechanisms underlying the biological effects of low dose/low dose rate ionizing radiation in organs/tissues of irradiated mice that differ in their susceptibility to ionizing radiation, and in human cells grown under conditions that mimic the natural in vivo environment. The focus was on the effects of sparsely ionizing cesium-137 gamma rays and the role of oxidative metabolism and intercellular communication in these effects. Four Specific Aims were proposed. The integrated outcome of the experiments performed to investigate these aims has been significant towards developing a scientific basis to more accurately estimate human health risks from exposures to low doses ionizing radiation. By understanding the biochemical and molecular changes induced by low dose radiation, several novel markers associated with mitochondrial functions were identified, which has opened new avenues to investigate metabolic processes that may be affected by such exposure. In particular, a sensitive biomarker that is differentially modulated by low and high dose gamma rays was discovered.

  17. Decoloration and detoxification of effluents by ionizing radiation

    Science.gov (United States)

    Borrely, Sueli I.; Morais, Aline V.; Rosa, Jorge M.; Badaró-Pedroso, Cintia; da Conceição Pereira, Maria; Higa, Marcela C.

    2016-07-01

    Three distinct textile samples were investigated for color and toxicity (S1-chemical/textile industry; S2-final textile effluent; S3 - standard textile produced effluent-untreated blue). Radiation processing of these samples were carried out at Dynamitron Electron Beam Accelerator and color and toxicity removal were determined: color removal by radiation was 96% (40 kGy, S1); 55% (2.5 kGy, S2) and 90% (2.5 kGy, S3). Concerning toxicity assays, Vibrio fischeri luminescent bacteria demonstrated higher reduction after radiation than the other systems: removal efficiencies were 33% (20 kGy, S1); 55% (2.5 kGy, S2) and 33% (2.5 kGy, S3). Daphnia similis and Brachionus plicatilis fitted well for S3 effluents. Hard toxic volumes into biological treatment plant may be avoided if radiation would be previously applied in a real plant. Results reveled how indispensable is to run toxicity to more than one living-organism.

  18. DUAL THEORY OF ACTION IONIZING RADIATION AND SPONTANEOUS CANCER

    Directory of Open Access Journals (Sweden)

    A. T. Gubin

    2015-01-01

    Full Text Available A mathematical model for radiogenic increasing of mortality was proposed, taking into account spontaneous background damages of the genetic material, that always occur in cells due to the influence of non-radiation internal and environmental factors. The model is based on the representation of indistinguishability between radiogenic andspontaneous cancers and on the postulates of the Kellerer-Rossi dual action theory. It was proposed that duringformation of premalignant damages dual interactions occur both between primary radiation damages, and betweenradiation and spontaneous primary damages (hybrid interactions. The role of the latter is particularly important at low levels exposure that corresponds to a linear dependence of cancer incidence on dose. Their significance is indicated by the following factor: at the adopted value of the nominal (radiation risk factor (0,05 Sv-1 and cancer mortality share among the population (0,15–0,2, the contribution of non-radiative carcinogenic factors for the total life is equivalent to radiation dose of 3–4 Sv or radiation at a constant dose rate of 40–50 mSv / year.The model assumes formation in DNA of both spaced apart (single damages with high probability of recovery, and nearby (double damages, which are more likely to interact, entering into the permanent state. Permanent damages being formed in certain portions of DNA can be inherited to daughter cells as premalignant defects. The relative role of spontaneous primary damages is greater the more single damages are formed as compared to double ones within the area of potential interaction.It was shown within this model that the presence of background cancer mortality for initial and finite population in the used by ICRP expression for interpopulation risk transfer has logical and biophysical justifications. Accounting of spontaneous primary damages and hybrid interactions enhances the capabilities for development of radiation risk models.

  19. Ionizing radiation - one of the most important link of the energetic chain in biological cell

    Energy Technology Data Exchange (ETDEWEB)

    Goraczko, W. [Technical Univ. Poznan, Radio- and Photochemistry Dept., Poznan (Poland)

    1999-09-01

    High (large) and low (small) doses of ionizing radiation consistently induce opposite physiologic effects in biological systems. The effects of low doses cannot be inferred by interpolation between the result from groups exposed to high doses and controls irradiated only by Natural Background Radiation. Stimulation ('bio-positive') effects by low-level doses of ionizing radiation are called radiation hormesis. It is still controversial idea, however it was found that some biological objects (yeast, seeds, animals) after gamma irradiation by low-level doses (10-50 times more NBR) can increase their development. The result of present researches demonstrate that the excitation of living system by gamma quanta (high energy) initiates prolonged secondary emission that influences biota and activates many important processes in biological systems. According to the excitation theory of bio-molecules the author suggests that gamma irradiation in low-level doses excites such molecules as DNA and proteins, and this being followed by a long-termed secondary coherent radiation. The spectral analysis of this secondary emission confirmed the contribution of the UV component to the total emission. The data obtaining by using SPC method (single photon counting) make possible a partial understanding of the radiation hormesis phenomenon and suggest closer relationship to UV emission from biological systems during mitotic processes. The experiments with humic acid (high doses) and glycine (low doses) confirm the author hypothesis that gamma-irradiated organic compounds are capable to emit secondary radiation. This secondary radiation probably plays very significant role in the intercellular communication inside the living systems. In conclusion the author proposed de-excitation processes in bio-molecules as a common denominator of UV and ionizing radiation interacting with living cells. Finally he refers to the Cerenkov radiation which is created inside the biological cells

  20. Cataract and ionizing radiation; Cataracte et rayonnements ionisants

    Energy Technology Data Exchange (ETDEWEB)

    Wassilieff, S. [Ecole des Applications Militaires de l' Energie Atomique, 50 - Cherbourg Octeville (France)

    2009-10-15

    The radiation-induced cataract has been up to now considered as a quite rare pathology, needing high-dose radiations (beyond a dose threshold roughly estimated at 2 Grays to the lens) consisting mainly in head tumour radiotherapy complications. Several new studies on different exposed populations such as astronauts, japanese atomic bomb survivors, people undergoing X-ray examinations, Chernobyl accident 'liquidators' as well as data from animal experiments, suggest that dose threshold for detectable opacities as well as for clinical posterior sub-capsular cataract occurring, might be far lower than those previously assumed. Even the existence of a dose threshold is no longer an absolute certitude insofar as radiation-induced cataract pathogenesis might consist not really in a deterministic effect (direct tissue harmful effect, killing or seriously injuring a critical population of cells) as believed until now, but rather in a stochastic effect (genomic damage in target-cells, altered cell division, abnormal lens fiber cell differentiation). More practically, these new data may lead us to reconsider radioprotection of specifically exposed populations: mainly patients and workers. Regarding workers, labour legislation (lens equivalent dose limit of 150 mSv during 12 consecutive months) might be, in the medium term, reassessed downwards. (author)

  1. Atmospheric Ionizing Radiation and the High Speed Civil Transport. Chapter 1

    Science.gov (United States)

    Maiden, D. L.; Wilson, J. W.; Jones, I. W.; Goldhagen, P.

    2003-01-01

    Atmospheric ionizing radiation is produced by extraterrestrial radiations incident on the Earth's atmosphere. These extraterrestrial radiations are of two sources: ever present galactic cosmic rays with origin outside the solar system and transient solar particle events that are at times very intense events associated with solar activity lasting several hours to a few days. Although the galactic radiation penetrating through the atmosphere to the ground is low in intensity, the intensity is more than two orders of magnitude greater at commercial aircraft altitudes. The radiation levels at the higher altitudes of the High Speed Civil Transport (HSCT) are an additional factor of two higher. Ionizing radiation produces chemically active radicals in biological tissues that alter the cell function or result in cell death. Protection standards against low levels of ionizing radiation are based on limitation of excess cancer mortality or limitation of developmental injury resulting in permanent damage to the offspring during pregnancy. The crews of commercial air transport operations are considered as radiation workers by the EPA, the FAA, and the International Commission on Radiological Protection (ICRP). The annual exposures of aircrews depend on the latitudes and altitudes of operation and flight time. Flight hours have significantly increased since deregulation of the airline industry in the 1980's. The FAA estimates annual subsonic aircrew exposures to range from 0.2 to 9.1 mSv compared to 0.5 mSv exposure of the average nuclear power plant worker in the nuclear industry. The commercial aircrews of the HSCT may receive exposures above recently recommended allowable limits for even radiation workers if flying their allowable number of flight hours. An adequate protection philosophy for background exposures in HSCT commercial airtraffic cannot be developed at this time due to current uncertainty in environmental levels. In addition, if a large solar particle event

  2. Responses to low doses of ionizing radiation in biological systems.

    Science.gov (United States)

    Feinendegen, Ludwig E; Pollycove, Myron; Sondhaus, Charles A

    2004-07-01

    Biological tissues operate through cells that act together within signaling networks. These assure coordinated cell function in the face of constant exposure to an array of potentially toxic agents, externally from the environment and endogenously from metabolism. Living tissues are indeed complex adaptive systems.To examine tissue effects specific for low-dose radiation, (1) absorbed dose in tissue is replaced by the sum of the energies deposited by each track event, or hit, in a cell-equivalent tissue micromass (1 ng) in all micromasses exposed, that is, by the mean energy delivered by all microdose hits in the exposed micromasses, with cell dose expressing the total energy per micromass from multiple microdoses; and (2) tissue effects are related to cell damage and protective cellular responses per average microdose hit from a given radiation quality for all such hits in the exposed micromasses.The probability of immediate DNA damage per low-linear-energy-transfer (LET) average micro-dose hit is extremely small, increasing over a certain dose range in proportion to the number of hits. Delayed temporary adaptive protection (AP) involves (a) induced detoxification of reactive oxygen species, (b) enhanced rate of DNA repair, (c) induced removal of damaged cells by apoptosis followed by normal cell replacement and by cell differentiation, and (d) stimulated immune response, all with corresponding changes in gene expression. These AP categories may last from less than a day to weeks and be tested by cell responses against renewed irradiation. They operate physiologically against nonradiogenic, largely endogenous DNA damage, which occurs abundantly and continually. Background radiation damage caused by rare microdose hits per micromass is many orders of magnitude less frequent. Except for apoptosis, AP increasingly fails above about 200 mGy of low-LET radiation, corresponding to about 200 microdose hits per exposed micromass. This ratio appears to exceed approximately

  3. Radionuclide Ionization in Protoplanetary Disks: Calculations of Decay Product Radiative Transfer

    CERN Document Server

    Cleeves, L Ilsedore; Bergin, Edwin A; Visser, Ruud

    2013-01-01

    We present simple analytic solutions for the ionization rate $\\zeta_{\\rm{SLR}}$ arising from the decay of short-lived radionuclides (SLRs) within protoplanetary disks. We solve the radiative transfer problem for the decay products within the disk, and thereby allow for the loss of radiation at low disk surface densities; energy loss becomes important outside $R\\gtrsim30$ for typical disk masses $M_g=0.04$ M$_\\odot$. Previous studies of chemistry/physics in these disks have neglected the impact of ionization by SLRs, and often consider only cosmic rays (CRs), because of the high CR-rate present in the ISM. However, recent work suggests that the flux of CRs present in the circumstellar environment could be substantially reduced by relatively modest stellar winds, resulting in severely modulated CR ionization rates, $\\zeta_{\\rm{CR}}$, equal to or substantially below that of SLRs ($\\zeta_{\\rm{SLR}}\\lesssim10^{-18}$ s$^{-1}$). We compute the net ionizing particle fluxes and corresponding ionization rates as a func...

  4. Induction of inositol 1,4,5 trisphosphate receptor genes by ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Yan, J. [Queensland Inst. of Medical Research, Brisbane, QLD (Australia)]|[Queensland Univ., Brisbane, QLD (Australia). Dept. of Surgery; Khanna, K.K.; Lavin, M.F. [Queensland Inst. of Medical Research, Brisbane, QLD (Australia)

    1996-05-01

    We used differential display, a method designed to amplify partial cDNA sequences from subsets of mRNAs, to identify mRNAs induced by ionizing radiation in human Epstein Barr Virus (EBV)-transformed lymphoblastoid cells. Increased expression of a cDNA corresponding to the inositol 1,4,5 trisphosphate receptor (InsP{sub 3}R) type 1 was observed after exposure of cells to 3Gy {gamma}-rays. This was confirmed by Northern blot analysis. The increase in mRNA for InsP{sub 3}R type 1 was accompanied by a corresponding increase in the level of InsP{sub 3}R type 1 protein as determined by Western blotting. Exposure of cells from patients with the human genetic disorder ataxia-telangiectasia (A-T), characterized by hypersensitivity to ionizing radiation, failed to change the levels of InsP{sub 3}R type 1 mRNA and, as expected, there was no increase in InsP{sub 3}R type 1 protein in A-T cells in response to radiation exposure. Protein levels for two other InsP{sub 3}Rs, types 2 and 3, were observed to increase in control and A-T cells after exposure to ionizing radiation. The induction of the InsP{sub 3}R type 1, which is primarily located in the endoplasmic reticulum, may play an important role in radiation signal transduction. (Author).

  5. [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.

  6. Stabilization of gas-filled surge arrester’s characteristics by use of ionizing radiation

    Directory of Open Access Journals (Sweden)

    Brajović Dragan V.

    2012-01-01

    Full Text Available This paper investigates the stabilization of electrical discharges in gases by means of external ionizing radiation. Discharges in a gas-filled surge arrester model were studied in both passive and active regimes of the device. An originally developed model of the gas-filled surge arrester was used. Gas pressure and the interelectrode gap were the variable parameters in our measurements. Applied radiation types included α-particles, γ-rays, X-rays, and neutrons. Measurements were performed under highly controlled laboratory conditions. The combined measurement uncertainty of the applied procedure was estimated as being under the 5% level. The results obtained are followed by a theoretical explanation. The crucial result is the conclusion that ionizing radiation does not necessarily degrade the gas-filled surge arrester’s functionality but that it, rather, improves it under certain conditions.

  7. Molecular Data for a Biochemical Model of DNA Radiation Damage: Electron Impact Ionization and Dissociative Ionization of DNA Bases and Sugar-Phosphate Backbone

    Science.gov (United States)

    Dateo, Christopher E.; Fletcher, Graham D.

    2004-01-01

    As part of the database for building up a biochemical model of DNA radiation damage, electron impact ionization cross sections of sugar-phosphate backbone and DNA bases have been calculated using the improved binary-encounter dipole (iBED) model. It is found that the total ionization cross sections of C3'- and C5'-deoxyribose-phospate, two conformers of the sugar-phosphate backbone, are close to each other. Furthermore, the sum of the ionization cross sections of the separate deoxyribose and phosphate fragments is in close agreement with the C3'- and C5'-deoxyribose-phospate cross sections, differing by less than 10%. Of the four DNA bases, the ionization cross section of guanine is the largest, then in decreasing order, adenine, thymine, and cytosine. The order is in accordance with the known propensity of oxidation of the bases by ionizing radiation. Dissociative ionization (DI), a process that both ionizes and dissociates a molecule, is investigated for cytosine. The DI cross section for the formation of H and (cytosine-Hl)(+), with the cytosine ion losing H at the 1 position, is also reported. The threshold of this process is calculated to be 17.1 eV. Detailed analysis of ionization products such as in DI is important to trace the sequential steps in the biochemical process of DNA damage.

  8. RADIONUCLIDE IONIZATION IN PROTOPLANETARY DISKS: CALCULATIONS OF DECAY PRODUCT RADIATIVE TRANSFER

    Energy Technology Data Exchange (ETDEWEB)

    Cleeves, L. Ilsedore; Adams, Fred C.; Bergin, Edwin A.; Visser, Ruud [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States)

    2013-11-01

    We present simple analytic solutions for the ionization rate ζ{sub SLR} arising from the decay of short-lived radionuclides (SLRs) within protoplanetary disks. We solve the radiative transfer problem for the decay products within the disk, and thereby allow for the loss of radiation at low disk surface densities; energy loss becomes important outside R ∼> 30 AU for typical disk masses M{sub g} = 0.04 M{sub ☉}. Previous studies of chemistry/physics in these disks have neglected the impact of ionization by SLRs, and often consider only cosmic rays (CRs), because of the high CR-rate present in the interstellar medium. However, recent work suggests that the flux of CRs present in the circumstellar environment could be substantially reduced by relatively modest stellar winds, resulting in severely modulated CR ionization rates, ζ{sub CR}, equal to or substantially below that of SLRs (ζ{sub SLR} ∼< 10{sup –18} s{sup –1}). We compute the net ionizing particle fluxes and corresponding ionization rates as a function of position within the disk for a variety of disk models. The resulting expressions are especially simple for the case of vertically Gaussian disks (frequently assumed in the literature). Finally, we provide a power-law fit to the ionization rate in the midplane as a function of gas disk surface density and time. Depending on location in the disk, the ionization rates by SLRs are typically in the range ζ{sub SLR} ∼ (1-10) × 10{sup –19} s{sup –1}.

  9. Ionizing radiation induced cataract; Katarakt-Induktion durch ionisierende Strahlung

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, W.U. [Universitaetsklinikum Essen (Germany). Inst. fuer Medizinische Strahlenbiologie

    2013-07-01

    Until recently it was believed that the cataract (opacity of the eye lens) is a deterministic effect with a dose threshold of several Gray in dependence on the exposure conditions. Studies in Hiroshima and Nagasaki, in the vicinity of Chernobyl, of American radiologic technologists, astronauts, and patients after having received several computer tomographies of the head region, however, have shown that this assumption is not correct. It had been overlooked in the past that with decreasing dose the latency period is increasing. Therefore, the originally available studies were terminated too early. The more recent studies show that, in the case of a threshold existing at all, it is definitely below 0.8 Gy independently of an acute or a chronic exposure. All studies, however, include 0 Gy in the confidence interval, so that the absence of a dose threshold cannot be excluded. The German Commission on Radiological Protection (Strahlenschutzkommission, SSK) suggested therefore among others: targeted recording of the lens dose during activities which are known to be associated with possible significant lens exposure, examination of the lens should be included as appropriate in the medical monitoring of people occupationally exposed to radiation, if there is potentially high lens exposure, adoption of research strategies to develop a basic understanding of the mechanisms underlying radiation induced cataracts. The International Commission on Radiological Protection (ICRP) actually assumes a threshold dose of 0.5 Gy and, based on this assumption, has recommended in 2011 to reduce the dose limit for the eye lens from 150 mSv in a year to 20 mSv in a year for people occupationally exposed to ionising radiation. (orig.)

  10. Response of hematopoietic stem cells to ionizing radiation; Reponse des cellules souches hematopoitiques aux radiations ionisantes

    Energy Technology Data Exchange (ETDEWEB)

    Simonnet, A

    2008-12-15

    Hematopoietic stem cells (HSCs) maintain blood and immune system throughout life and restore them after hematological injuries. Exposure of an organism to ionizing radiation (IR) causes rapid and acute myelosuppression and challenges the replenishment capacity of HSCs. Yet, the precise damages that are generated remain largely unexplored. To better understand these effects, phenotypic and functional changes in the stem/progenitor compartments of sublethally irradiated mice were monitored over a ten week period after radiation exposure. We report that shortly after sublethal IR-exposure, HSCs, defined by their repopulating ability, still segregate in the Hoechst dye excluding side population (SP); yet, their Sca-1 (S) and c-Kit (K) expression levels are increased and severely reduced, respectively, with a concurrent increase in the proportion of SP{sup SK} cells positive for established indicators of HSC presence: CD150{sup +} and CD105{sup +}. A great proportion of HSCs quickly but transiently enter the cell cycle to replenish the bone marrow of myelo-ablated mice. Ten weeks after, whereas bone marrow cellularity has recovered and hematopoietic homeostasis is restored, major phenotypic modifications can be observed within the Lin{sup -/low} Sca-1{sup +} c-Kit{sup +} (LSK) stem/progenitor compartment: CD150{sup +}/Flk2{sup -} and CD150{sup -}/Flk2{sup +} LSK cell frequencies are increased and dramatically reduced, respectively. CD150{sup +} LSK cells also show impaired reconstitution capacity, accrued number of {gamma}-H2AX foci and increased tendency to apoptosis. This demonstrates that the LSK compartment is not properly restored 10 weeks after sublethal exposure, and that long-term IR-induced injury to the bone marrow proceeds, at least partially, through direct damage to the stem cell pool. Thrombopoietin (TPO) has been shown to promote the survival of lethally irradiated mice when administrated quickly after exposure. We investigated the mechanisms underlying

  11. Effect of ionizing radiation on the waste package environment

    Energy Technology Data Exchange (ETDEWEB)

    Reed, D.T. [Argonne National Lab., IL (USA); Van Konynenburg, R.A. [Lawrence Livermore National Lab., CA (USA)

    1991-05-01

    The radiolytic production of nitrogen oxides, nitrogen acids and ammonia are discussed in relation to the expected environment in a high-level waste repository that may be constructed at the Yucca Mountain site if it is found to be suitable. Both literature data and repository-relevant data are summarized for air-water vapor systems. The limiting cases of a dry air and a pure water vapor gas phase are also discussed. Design guidelines and recommendations, based solely on the potential consequence of radiation enhancement of corrosion, are given. 13 refs., 5 figs., 1 tab.

  12. [Ionizing radiation in the aeronautics industry. Non-destructive testing].

    Science.gov (United States)

    La Verde, R; Travaglini, C

    1983-08-25

    The constant increase in the non-military use of nuclear energy in various fields induced this study of one particular field: the aero industry. Alitalia has been using gammagraphy and industrial metallography for nondestructive testing for over 20 years. Workers exposed to ionising radiations at work are protected by precisely detailed standards based on extremely rigorous national and international legislation. The health and protection of these workers is entrusted to a Company Doctor and a Qualified Specialist. The latter is thought to be indispensable since he is responsible for primary preventions as well as prompt diagnosis.

  13. Biological effect of non-ionizing radiations on microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Kikuo; Yamamoto, Takayoshi [Osaka Univ., Radioisotope Research Center, Suita, Osaka (Japan); Nakaoka, Yasuo [Osaka Univ., Graduate School of Engineering Science, Department of Biophysical Engineering, Toyonaka, Osaka (Japan)

    2000-05-01

    We studied the effect of extremely low frequency magnetic fields (ELF-MF) of 60-Hz and 500 mT on the growth and the mutation frequency of the budding yeast S.cerevisiae and on the behavior of the ciliate Paramecium multimicronucleatum. The growth rate and mutation frequencies of several strains of S.cerevisiae (wild type and radiation sensitive mutants, rad or rev) were examined but no significant difference was observed. Moreover, the behavior of P.multimicronucleatum under the ELF-MF was examined. When exposed to a vertical field of 0.6 T, the cells accumulated at the upper end of the cuvette. (author)

  14. Multifluid Modeling of the Partially Ionized Chromosphere with Effects of Impact Ionization, Radiative Recombination and Charge Exchange

    Science.gov (United States)

    Maneva, Y. G.; Poedts, D. S.; Alvarez Laguna, A.; Lani, A.

    2015-12-01

    Neutrals play an important role in the evolution of the weakly ionized solar chromosphere where the number density of neutrals can vastly exceed the number density of protons. Therefore modeling the neutral-ion interactions and studying the effect of neutrals on the ambient plasma properties is an important task for better understanding the observed emission lines and the propagation of disturbances from the photosphere to the transition region and the corona. To pursue this goal we have developed two-fluid and three-fluid simulation setups to study the interaction between electrons, ions and neutrals in a reactive gravitationally stratified collisional media. The model considers the electrons and ions within the resistive MHD approach with Coulomb collisions and anisotropic heat flux determined by Braginskii's transport coefficients. The electromagnetic fields are evolved according to the full Maxwell equations, allowing for propagation of higher frequency waves neglected by the standard MHD approximation. Separate mass, momentum and energy conservation equations are considered for the neutrals and the interaction between the different fluids is determined by the chemical reactions, such as impact ionization, radiative recombination and charge exchange, provided as additional source terms. To initialize the system we consider an ideal gas equation of state with equal initial temperatures for the electrons, ions and the neutrals and different density profiles. The initial temperature and density profiles are height-dependent and follow VAL C atmospheric model for the solar chromosphere. We have searched for a chemical and collisional equilibrium between the ions and the neutrals in the hydrostatic case to avoid unphysical outflows and artificial heating induced by initial pressure imbalances. Next we consider ion-neutral interactions in magnetized plasma with an initial magnetic profile, corresponding to emerging magnetic funnel. Finally we include an external

  15. A semiconductor parameter analyzer for ionizing radiation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Luiz A.P., E-mail: lasantos@cnen.gov.b [Centro Regional de Ciencias Nucleares (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2009-07-01

    Electrometers and ion chamber are normally used to make several types of measurements in a radiation field and there is a unique voltage applied to each detector type. Some electronic devices that are built of semiconductor materials like silicon crystal can also be used for the same purpose. In this case, a characteristic curve of the device must be acquired to choose an operation point which consists of an electrical current or voltage to be applied to the device. Unlike ion chambers, such an electronic device can have different operation points depending on its current versus voltage curve (I x V). The best operation point of the device is also a function of the radiation, energy, dose rate and fluence. The purpose of this work is to show a semiconductor parameter analyzer built to acquire I x V curves as usually, and the innovation here is the fact that it can be used to obtain such a parametric curve when a quad-polar device is under irradiation. The results demonstrate that the system is a very important tool to scientists interested to evaluate a semiconductor detector before, during and after irradiation. A collection of results for devices under an X-ray beam and a neutron fluence are presented: photodiode, phototransistors, bipolar transistor and MOSFET. (author)

  16. Prenatal exposure to ionizing radiation and subsequent development of seizures

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, K.; Yoshimaru, H.; Otake, M.; Annegers, J.F.; Schull, W.J. (Radiation Effects Research Foundation, Hiroshima (Japan))

    1990-01-01

    Seizures are a frequent sequela of impaired brain development and can be expected to affect more children with radiation-related brain damage than children without such damage. This report deals with the incidence and type of seizures among survivors prenatally exposed to the atomic bombing of Hiroshima and Nagasaki, and their association with specific stages of prenatal development at the time of irradiation. Fetal radiation dose was assumed to be equal to the dose to the maternal uterus. Seizures here include all references in the clinical record to seizure, epilepsy, or convulsion. Histories of seizures were obtained at biennial routine clinical examinations starting at about the age of 2 years. These clinical records were used to classify seizures as febrile or unprovoked (without precipitating cause). No seizures were ascertained among subjects exposed 0-7 weeks after fertilization at doses higher than 0.10 Gy. The incidence of seizures was highest with irradiation at the eighth through the 15th week after fertilization among subjects with doses exceeding 0.10 Gy and was linearly related to the level of fetal exposure. This obtains for all seizures without regard to the presence of fever or precipitating causes, and for unprovoked seizures. When the 22 cases of severe mental retardation were excluded, the increase in seizures was only suggestively significant and only for unprovoked seizures. After exposure at later stages of development, there was no increase in recorded seizures.

  17. Quantitative phosphoproteomics identifies filaggrin and other targets of ionizing radiation in a human skin model.

    Science.gov (United States)

    Yang, Feng; Waters, Katrina M; Webb-Robertson, Bobbie-Jo; Sowa, Marianne B; von Neubeck, Claere; Aldrich, Josh T; Markillie, Lye Meng; Wirgau, Rachel M; Gritsenko, Marina A; Zhao, Rui; Camp, David G; Smith, Richard D; Stenoien, David L

    2012-05-01

    Our objective here was to perform a quantitative phosphoproteomic study on a reconstituted human skin tissue to identify low- and high-dose ionizing radiation-dependent signalling in a complex three-dimensional setting. Application of an isobaric labelling strategy using sham and three radiation doses (3, 10, 200 cGy) resulted in the identification of 1052 unique phosphopeptides. Statistical analyses identified 176 phosphopeptides showing significant changes in response to radiation and radiation dose. Proteins responsible for maintaining skin structural integrity including keratins and desmosomal proteins (desmoglein, desmoplakin, plakophilin 1, 2 and 3) had altered phosphorylation levels following exposure to both low and high doses of radiation. Altered phosphorylation of multiple sites in profilaggrin linker domains coincided with altered profilaggrin processing suggesting a role for linker phosphorylation in human profilaggrin regulation. These studies demonstrate that the reconstituted human skin system undergoes a coordinated response to both low and high doses of ionizing radiation involving multiple layers of the stratified epithelium that serve to maintain tissue integrity and mitigate effects of radiation exposure.

  18. Biodosimetry of ionizing radiation by selective painting of prematurely condensed chromosomes in human lymphocytes

    Science.gov (United States)

    Durante, M.; George, K.; Yang, T. C.

    1997-01-01

    Painting of interphase chromosomes can be useful for biodosimetric purposes in particular cases such as radiation therapy, accidental exposure to very high radiation doses and exposure to densely ionizing radiation, for example during space missions. Biodosimetry of charged-particle radiation is analyzed in the present paper. Target cells were human peripheral blood lymphocytes irradiated in vitro with gamma rays, protons and iron ions. After exposure, lymphocytes were incubated for different times to allow repair of radiation-induced damage and then fused to mitotic hamster cells to promote premature condensation in the interphase chromosomes. Chromosome spreads were then hybridized with whole-chromosome DNA probes labeled with fluorescent stains. Dose-response curves for the induction of chromatin fragments shortly after exposure, as well as the kinetics of rejoining and misrejoining, were not markedly dependent on linear energy transfer. However, after exposure to heavy ions, more aberrations were scored in the interphase cells after incubation for repair than in metaphase samples harvested at the first postirradiation mitosis. On the other hand, no significant differences were observed in the two samples after exposure to sparsely ionizing radiation. These results suggest that interphase chromosome painting can be a useful tool for biodosimetry of particle radiation.

  19. Total ionizing dose radiation effects on NMOS parasitic transistors in advanced bulk CMOS technology devices

    Science.gov (United States)

    Baoping, He; Zujun, Wang; Jiangkun, Sheng; Shaoyan, Huang

    2016-12-01

    In this paper, total ionizing dose effect of NMOS transistors in advanced CMOS technology are examined. The radiation tests are performed at 60Co sources at the dose rate of 50 rad (Si)/s. The investigation's results show that the radiation-induced charge buildup in the gate oxide can be ignored, and the field oxide isolation structure is the main total dose problem. The total ionizing dose (TID) radiation effects of field oxide parasitic transistors are studied in detail. An analytical model of radiation defect charge induced by TID damage in field oxide is established. The I - V characteristics of the NMOS parasitic transistors at different doses are modeled by using a surface potential method. The modeling method is verified by the experimental I - V characteristics of 180 nm commercial NMOS device induced by TID radiation at different doses. The model results are in good agreement with the radiation experimental results, which shows the analytical model can accurately predict the radiation response characteristics of advanced bulk CMOS technology device. Project supported by the National Natural Science Foundation of China (No. 11305126).

  20. Effects of ionizing radiation on changes in the level of gibberellin-like substances during Scotch pine seeds germination

    Directory of Open Access Journals (Sweden)

    Leszek Michalski

    2015-01-01

    Full Text Available The level of gibberellin-like substances in pine seeds exposed to ionizing radiation was investigated using extraction, fractionation, acid hydrolysis, partitioning on chromatographic columns and biological tests. It was found that the level of free and bound gibberellin-like substances is dependent on the applied gamma radiation dose. It is assumed that ionizing radiation may re-lease bound gibberellins into free ones.

  1. Biological effects of the ionizing radiation. Press breakfast; Effets biologiques des rayonnements ionisants. Petit dejeuner de presse

    Energy Technology Data Exchange (ETDEWEB)

    Flury-Herard, A. [CEA, Direction des Sciences du Vivant, DSV, 75 - Paris (France); Boiteux, S.; Dutrillaux, B. [CEA/Fontenay-aux-Roses, Direction des Sciences du Vivant, DSV, 92 (France); Toledano, M. [CEA Saclay, Direction des Sciences du Vivant, DSV, 91 - Gif-sur-Yvette (France)

    2000-06-01

    This document brings together the subjects discussed during the Press breakfast of 29 june 2000 on the biological effects of the ionizing radiations, with scientists of the CEA and the CNRS. It presents the research programs and provides inquiries on the NDA operating to introduce the NDA damages by ionizing radiations, the possible repairs and the repair efficiency facing the carcinogenesis. Those researches allow the scientists to define laws on radiation protection. (A.L.B.)

  2. Thin films deposited by laser ablation for the measurement of the ionizing and non-ionizing radiation; Peliculas delgadas depositadas por ablacion laser para la medicion de radiacion ionizante y no ionizante

    Energy Technology Data Exchange (ETDEWEB)

    Villarreal B, J.E.; Escobar A, L.; Camps, E.; Romero, S.; Gonzalez, P.; Salinas, B. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2001-07-01

    In this work the obtained results to synthesize thin films of amorphous carbon with incorporated nitrogen and hydrogen are presented, as well as thin films of aluminium oxide using the laser ablation technique. The thin films were exposed to ionizing radiation (gamma rays of a {sup 60} Co source, beta radiation of a {sup 90} Sr source) and a non-ionizing radiation (UV radiation). The obtained results show that it is possible to obtain materials in thin film form with thickness of hundreds of nanometers, which present thermoluminescent response when being irradiated with ionizing radiation and non-ionizing radiation. (Author)

  3. Stability evaluation of resveratrol submitted to ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Momesso, Roberta G.R.A.P.; Silva, Mariana L. da; Spencer, Patrick J.; Sousa, Jose M. de; Rogero, Jose R.; Rogero, Sizue O.; Lugao, Ademar B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil)], e-mail: robertapassarelli@yahoo.com.br

    2009-07-01

    The polyphenol trans-resveratrol (trans-3, 4',5-trihydroxystilbene) is a natural phytoalexin, reported to exert different biological activities, such as antioxidant properties. In the attempt to make possible the topic administration of resveratrol it will be immobilized in a hydrogel matrix obtained by gamma radiation crosslinking process which can cause undesirable hydrolysis reactions in the active compound. The aim of this work was to verify the aqueous/ethanol resveratrol solution stability and antioxidant activity after irradiation at 20 kGy. The integrity and stability were compared with nature one by High Performance Liquid Chromatography (HPLC) technique. The antioxidant activity was determined by the free radical scavenging method, using 2,2-Diphenyl-1-picrylhydrazyl (DPPH.) as free radical. The results demonstrated the decomposition of resveratrol and reduction of antioxidant capacity after irradiation at 20 kGy dose. (author)

  4. Assessment of risks from occupational exposure to ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Gilbert, E. S.

    1979-01-01

    The assessment of health effects from occupational exposure to radiation presents a variety of problems resulting from the time dependent nature of the exposure data, the more favorable health frequently experienced by working populations, and limits imposed by the size of the populations and the magnitudes of the exposures received. A proportional hazards model is used to derive tests for determining if statistically significant effects are present and is also considered for point estimation. Because effects of the size expected from current estimates are unlikely to be detected in occupationally exposed groups, methods of calculating upper confidence limits are considered. Data from the Hanford plant are used to illustrate many of the problems and procedures.

  5. [Scrap metal and ionizing radiation hazard: prevention and protection].

    Science.gov (United States)

    Giugni, U

    2012-01-01

    The numerous accidents occurred in companies that melt scrap metals have shown that the hazard caused by the presence of radioactive materials--or 'orphan sources'--may have serious consequences on standard production, with great economic and social damage. Italian Legislative Decree No. 100/11 establishes the skills required for the safe management of scrap metals in the whole production cycle, thus requiring the involvement of experts in radiation protection. The paper details the procedures that shall be implemented in the companies that melt scrap metals. Said procedures involve several professional roles: managers, department heads and occupational physicians. The paper describes the general characteristics of the instruments used, staff training programs and the experience gained in 15 years of activity.

  6. An Exploratory Analysis of Public Awareness and Perception of Ionizing Radiation and Guide to Public Health Practice in Vermont.

    Science.gov (United States)

    Evans, Katherine M; Bodmer, Jenna; Edwards, Bryce; Levins, James; O'Meara, Amanda; Ruhotina, Merima; Smith, Richard; Delaney, Thomas; Hoffman-Contois, Razelle; Boccuzzo, Linda; Hales, Heidi; Carney, Jan K

    2015-01-01

    Exposure to ionizing radiation has potential for acute and chronic health effects. Within the general public of the United States, there may be a discrepancy between perceived and actual health risks. In conjunction with the Vermont Department of Health, a survey designed to assess public perception and knowledge of ionizing radiation was administered at 6 Vermont locations (n = 169). Descriptive and inferential statistical analyses were conducted. Eighty percent of respondents underestimated the contribution of medical imaging tests to total ionizing radiation exposure. Although only thirty-nine percent of participants were confident in their healthcare professional's knowledge of ionizing radiation, most would prefer to receive information from their healthcare professional. Only one-third of individuals who received a medical imaging test in the past year were educated by their healthcare professional about the risks of these tests. Those who tested their home for radon were twice as likely to choose radon as the greatest ionizing radiation risk to self. Although respondents had an above-average education level, there were many misperceptions of actual risks of exposure to ionizing radiation, particularly of medical imaging tests. Educating healthcare professionals would therefore have a profound and positive impact on public understanding of ionizing radiation.

  7. Interactive Visual Intervention Planning: Interactive Visualization for Intervention Planning in Particle Accelerator Environments with Ionizing Radiation

    CERN Document Server

    Fabry, Thomas; Feral, Bruno

    2013-01-01

    Intervention planning is crucial for maintenance operations in particle accelerator environments with ionizing radiation, during which the radiation dose contracted by maintenance workers should be reduced to a minimum. In this context, we discuss the visualization aspects of a new software tool, which integrates interactive exploration of a scene depicting an accelerator facility augmented with residual radiation level simulations, with the visualization of intervention data such as the followed trajectory and maintenance tasks. The visualization of each of these aspects has its effect on the final predicted contracted radiation dose. In this context, we explore the possible benefits of a user study, with the goal of enhancing the visual conditions in which the intervention planner using the software tool is minimizing the radiation dose.

  8. Influence of XUV radiation on Pv ionization fraction in hot star winds

    CERN Document Server

    Krticka, Jiri

    2012-01-01

    Different diagnostics of hot star wind mass-loss rates provide results that are difficult to reconcile with each other. The widely accepted presence of clumping in hot star winds implies a significant reduction of observational mass-loss rate estimates from diagnostics that depend on the square of the density. Moreover, the ultraviolet Pv resonance lines indicate a possible need for even stronger reduction of hot star mass-loss rates, provided that Pv is a dominant ionization stage of phosphorus at least in some hot stars. The latter assumption is challenged by a possible presence of the XUV radiation. Here we study the influence of the XUV radiation on the Pv ionization fraction in the hot star winds. By a detailed solution of the hydrodynamical, radiative transfer, and statistical equilibrium equations we confirm that sufficiently strong XUV radiation source may decrease the Pv ionization fraction, possibly depreciating the Pv lines as a reliable mass-loss rate indicator. On the other hand, the XUV radiatio...

  9. Ionizing radiation test results for an automotive microcontroller on board the Schiaparelli Mars lander

    Science.gov (United States)

    Tapani Nikkanen, Timo; Hieta, Maria; Schmidt, Walter; Genzer, Maria; Haukka, Harri; Harri, Ari-Matti

    2016-04-01

    The Finnish Meteorological Institute (FMI) has delivered a pressure and a humidity instrument for the ESA ExoMars 2016 Schiaparelli lander mission. Schiaparelli is scheduled to launch towards Mars with the Trace Gas Orbiter on 14th of March 2016. The DREAMS-P (pressure) and DREAMS-H (Humidity) instruments are operated utilizing a novel FMI instrument controller design based on a commercial automotive microcontroller (MCU). A custom qualification program was implemented to qualify the MCU for the relevant launch, cruise and surface operations environment of a Mars lander. Resilience to ionizing radiation is one of the most critical requirements for a digital component operated in space or at planetary bodies. Thus, the expected Total Ionizing Dose accumulated by the MCU was determined and a sample of these components was exposed to a Co-60 gamma radiation source. Part of the samples was powered during the radiation exposure to include the effect of electrical biasing. All of the samples were verified to withstand the expected total ionizing dose with margin. The irradiated test samples were then radiated until failure to determine their ultimate TID.

  10. A cytogenetic approach to the effects of low levels of ionizing radiations on occupationally exposed individuals

    Energy Technology Data Exchange (ETDEWEB)

    Zakeri, Farideh [National Radiation Protection Department, Iranian Nuclear Regulatory Authority, Nuclear Science and Research Institute-Agriculture, Medicine and Industry Research School, Tehran (Iran, Islamic Republic of); Graduate School of Science and Technology, Chiba University, Inage-ku, Chiba 263-8522 (Japan)], E-mail: fzakeri@aeoi.org.ir; Hirobe, Tomohisa [Graduate School of Science and Technology, Chiba University, Inage-ku, Chiba 263-8522 (Japan); Radiation Effect Mechanism Research Group, National Institute of Radiological Sciences, Inage-ku, Chiba 263-8555 (Japan)

    2010-01-15

    The aim of the present study was to assess occupationally induced chromosomal damage in hospital workers exposed to low levels of ionizing radiation. Thirty-two interventional cardiologists, 36 nuclear medicine physicians and 33 conventional radiologists were included in this study, along with 35 healthy age- and sex-matched individuals as the control group. We used conventional metaphase chromosome aberration (CA) analysis, cytokinesis-block micronucleus (MN) assay as important biological indicators of ionizing radiation exposure. Occupational dosimetry records were collected over the last year (ranged from 0.25 to 48 mSv) and their whole life exposure (ranged from 1.5 to 147 mSv). The results showed significantly higher frequencies of dicentric and acentric CAs (p < 0.001) and MN (p < 0.01) in all exposed groups than in the controls. Taking all the confounding factors into account, no obvious trend of increased chromosomal damages as a function of either duration of employment, exposed dose, sex or age was observed. Interventional cardiologists had the highest rates of CA and MN frequencies between the worker groups, though the differences were not significant. These results indicate that long term exposure to low dose ionizing radiation could result in DNA damage. Hence, the personnel who work in the hospitals should carefully apply the radiation protection procedures.

  11. Free Radicals Generated by Ionizing Radiation Signal Nuclear Translocation of p53

    Science.gov (United States)

    Martinez, J. D.; Pennington, M. E.; Craven, M. T.; Warters, R. L.

    1997-01-01

    The p53 tumor suppressor is a transcription factor that regulates several pathways, which function collectively to maintain the integrity of the genome. Nuclear localization is critical for wild-type function. However, the signals that regulate subcellular localization of p53 have not been identified. Here, we examine the effect of ionizing radiation on the subcellular localization of p53 in two cell lines in which p63 is normally sequestered in the cytoplasm and found that ionizing radiation caused a biphasic translocation response. p53 entered the nucleus 1-2 hours postirradiation (early response), subsequently emerged from the nucleus, and then again entered the nucleus 12-24 hours after the cells had been irradiated (delayed response). These changes in subcellular localization could be completely blocked by the free radical scavenger, WR1065. By comparison, two DNA-damaging agents that do not generate free radicals, mitomycin C and doxorubicin, caused translocation only after 12-24 h of exposure to the drugs, and this effect could not be inhibited by WR1065. Hence, although all three DNA-damaging agents induced relocalization of p53 to the nucleus, only the translocation caused by radiation was sensitive to free radical scavenging. We suggest that the free radicals generated by ionizing radiation can signal p53 translocation to the nucleus.

  12. Radiative Lifetime Measurements of Even-Parity Levels of Singly Ionized Erbium

    Institute of Scientific and Technical Information of China (English)

    XU Huai-Liang(徐淮良); JIANG Hong-Mei(蒋红梅); LIU Qian(刘倩); JIANG Zhan-Kui(蒋占魁); S.Svanberg

    2004-01-01

    Radiative lifetime measurements were performed by time-resolved laser-induced fluorescence (LIF) technique for eight even-parity levels of the astrophysically importantion Er+ over the energy range from 33753 to 55317 cm-1.Free erbium ions were generated by a laser-induced plasma. A narrow bandwidth UV laser pulse (1 ns) was employed to populate selectively the short-lived upper levels, and the lifetime value were evaluated from the time-resolved fluorescence signals. The lifetimes reported fall in the range of 3-35 ns with the experimental accuracy 5-8%.

  13. 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

  14. Biological dosimetry -- cytogenetics findings at persons occupationally exposed to ionizing radiation.

    Science.gov (United States)

    Catović, Amra; Tanacković, Fikreta

    2006-05-01

    A large number of physical and chemical agents are capable to course chromosomal aberrations. Ionizing radiation is frequent and well known course of chromosomal aberrations. If deoxyribonucleic acid (DNA) is irradiated before synthesis chromosomal-type aberrations are caused. Chromatid-type aberrations are results of DNA damages occurred during or after synthesis. Some of these changes could exist at patients several years after exposition. Biological dosimetry-cytogenetics analysis of persons occupational exposed to ionizing radiation in Federation of Bosnia and Herzegovina have been carried out in "Center for Human Genetics" of Medical Faculty in Sarajevo. In this study we have evaluated cytogenetics findings of persons employed in a zone of radiation. Cytogenetics findings have been demonstrated in allowed limit in 154 (81.1%) examinees, and cytogenetics findings were out of normal values in 36 (18.9%) examinees. The majorities who have been employed in a zone of ionizing radiation were in age group 40-44 (25.3%) and age group 45-49 (24.7%). Radiological technicians (35.7%) were exposed the most to ionizing radiation, than clinical nurse specialists (14.7%), radiologists (11.1), physicians (7.4%) machines technicians (6.3%), pneumologists (4.7%), orthopedists (4.2%) and scrub nurses (4.2%). Biological dosimetry-cytogenetics analysis have been carried out at 108 (56.8%) male and 82 (43.2%) female examinees. The most frequent aberration have been presented with 26.8% in the form of acentric fragments, than chromatid fragments with 21.2%, dicentric chromosomes with 19.5%, gaps with 18.7%, minutes with 12.2% and inter-arm interchanges with 1.6%.

  15. Repeated Nrf2 stimulation using sulforaphane protects fibroblasts from ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Mathew, Sherin T.; Bergström, Petra; Hammarsten, Ola, E-mail: ola.hammarsten@clinchem.gu.se

    2014-05-01

    Most of the cytotoxicity induced by ionizing radiation is mediated by radical-induced DNA double-strand breaks. Cellular protection from free radicals can be stimulated several fold by sulforaphane-mediated activation of the transcription factor Nrf2 that regulates more than 50 genes involved in the detoxification of reactive substances and radicals. Here, we report that repeated sulforaphane treatment increases radioresistance in primary human skin fibroblasts. Cells were either treated with sulforaphane for four hours once or with four-hour treatments repeatedly for three consecutive days prior to radiation exposure. Fibroblasts exposed to repeated-sulforaphane treatment showed a more pronounced dose-dependent induction of Nrf2-regulated mRNA and reduced amount of radiation-induced free radicals compared with cells treated once with sulforaphane. In addition, radiation- induced DNA double-strand breaks measured by gamma-H2AX foci were attenuated following repeated sulforaphane treatment. As a result, cellular protection from ionizing radiation measured by the 5-ethynyl-2′-deoxyuridine (EdU) assay was increased, specifically in cells exposed to repeated sulforaphane treatment. Sulforaphane treatment was unable to protect Nrf2 knockout mouse embryonic fibroblasts, indicating that the sulforaphane-induced radioprotection was Nrf2-dependent. Moreover, radioprotection by repeated sulforaphane treatment was dose-dependent with an optimal effect at 10 uM, whereas both lower and higher concentrations resulted in lower levels of radioprotection. Our data indicate that the Nrf2 system can be trained to provide further protection from radical damage. - Highlights: • Repeated treatment with sulforaphane protects fibroblasts from ionizing radiation • Repeated sulforaphane treatment attenuates radiation induced ROS and DNA damage • Sulforaphane mediated protection is Nrf2 dependent.

  16. Charge transfer and penning ionization of dopants in or on helium nanodroplets exposed to EUV radiation.

    Science.gov (United States)

    Buchta, Dominic; Krishnan, Siva R; Brauer, Nils B; Drabbels, Marcel; O'Keeffe, Patrick; Devetta, Michele; Di Fraia, Michele; Callegari, Carlo; Richter, Robert; Coreno, Marcello; Prince, Kevin C; Stienkemeier, Frank; Moshammer, Robert; Mudrich, Marcel

    2013-05-30

    Helium nanodroplets are widely used as a cold, weakly interacting matrix for spectroscopy of embedded species. In this work, we excite or ionize doped He droplets using synchrotron radiation and study the effect onto the dopant atoms depending on their location inside the droplets (rare gases) or outside at the droplet surface (alkali metals). Using photoelectron-photoion coincidence imaging spectroscopy at variable photon energies (20-25 eV), we compare the rates of charge-transfer to Penning ionization of the dopants in the two cases. The surprising finding is that alkali metals, in contrast to the rare gases, are efficiently Penning ionized upon excitation of the (n = 2)-bands of the host droplets. This indicates rapid migration of the excitation to the droplet surface, followed by relaxation, and eventually energy transfer to the alkali dopants.

  17. Formation region effects in transition radiation, bremsstrahlung, and ionization loss of ultrarelativistic electrons

    Science.gov (United States)

    Trofymenko, S. V.; Shul'ga, N. F.

    2016-11-01

    The processes of transition radiation and bremsstrahlung by an ultrarelativistic electron as well as the effect of transition radiation influence upon the electron ionization loss in thin layer of substance are theoretically investigated in the case when radiation formation region has macroscopically large size. Special attention is drawn to transition radiation (TR) generated during the traversal of thin metallic plate by the electron previously deflected from its initial direction of motion. In this case TR characteristics are calculated for realistic (circular) shape of the electron deflection trajectory. The difference of such characteristics under certain conditions from the ones obtained previously with the use of approximation of anglelike shape of the electron trajectory (instant deflection) is shown. The problem of measurement of bremsstrahlung characteristics in the prewave zone is investigated. The expressions defining the measured radiation distribution for arbitrary values of the size and the position of the detector used for radiation registration are derived. The problem of TR influence upon the electron ionization loss in thin plate and in a system of two plates is discussed. The proposal for experimental investigation of such effect is formulated.

  18. Genetic variation in normal tissue toxicity induced by ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Popanda, Odilia, E-mail: o.popanda@dkfz.de [Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Marquardt, Jens Uwe [Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Chang-Claude, Jenny [Division of Cancer Epidemiology, German Cancer Research Center (DKFZ), Heidelberg (Germany); Schmezer, Peter [Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany)

    2009-07-10

    Radiotherapy is an important weapon in the treatment of cancer, but adverse reactions developing in the co-irradiated normal tissue can be a threat for patients. Early reactions might disturb the usual application schedule and limit the radiation dose. Late appearing and degenerative reactions might reduce or destroy normal tissue function. Genetic markers conferring the ability to identify hyper-sensitive patients in advance would considerably improve therapy. Association studies on genetic variation and occurrence of side effects should help to identify such markers. This survey includes published studies and novel data from our own laboratory. It illustrates the presence of candidate polymorphisms in genes involved in the cellular response to irradiation which could be used as predictive markers for radiosensitivity in breast or prostate cancer patients. For other tumor types such as head and neck cancers or brain tumors, the available data are much more limited. In any case, further validation of these markers is needed in large patient cohorts with systematically recorded data on side effects and patient characteristics. Genetic variation contributing to radiosensitivity should be screened on a broader basis using newly developed, more comprehensive approaches such as genome-wide association studies.

  19. Astrophysical S factor for the radiative-capture reaction p{sup 6}Li {yields} {sup 7}Be{gamma}

    Energy Technology Data Exchange (ETDEWEB)

    Dubovichenko, S. B., E-mail: sergey@dubovichenko.ru [National Space Agency of the Republic of Kazakhstan, Fessenkov Astrophysical Institute, National Center of Space Research and Technology (Kazakhstan); Burtebaev, N., E-mail: burteb@inp.kz; Zazulin, D. M.; Kerimkulov, Zh. K. [National Nuclear Center of Republic of Kazakhstan, Institute of Nuclear Physics (Kazakhstan); Amar, A. S. A. [Al-Farabi Kazakh National University (Kazakhstan)

    2011-07-15

    A new measurement of differential cross sections for elastic p{sup 6}Li scattering in the energy range 0.35-1.2 MeV was performed. A partial-wave analysis of the data obtained in this way was carried out, and potentials simulating the p{sup 6}Li interaction were constructed. Various experiments devoted to studying elastic p{sup 6}Li scattering over the broad energy range of 0.5-50 MeV were analyzed on the basis of the optical model. By using the potentials obtained from the partial-wave analysis, the possibility of describing the astrophysical S factor for radiative proton capture on {sup 6}Li at low energies was considered within the potential cluster model involving forbidden states.

  20. Thin plastic radiochromic dye films as ionizing radiation dosimeters

    Science.gov (United States)

    Buenfil-Burgos, A. E.; Uribe, R. M.; de la Piedad, A.; McLaughlin, W. L.; Miller, A.

    Radiochromic dye films were fabricated by casting polyvinyl butyral (PVB) in weakly acidic solution with the leucocyanide of pararosaniline. Calibrated films of 10-25 μm thickness were useful over a response range of about 10 3-10 5 Gy, by applying spectrophotometric analysis at the wavelength of the maximum of the radiation-induced absorption band (550 nm). The effects of temperature, pressure, and humidity during curing of the films pointed to the need for carefully controlling these parameters. For casting films at the high altitude of Mexico City (≈ 2500 meters), the optimum conditions are 45-75% r.h. and 20-25° C for a drying period of 72 to 92 hours, when the solvent is a mixture of ethanol and 2-methoxyethanol. The response of films fabricated in this way were compared with those of commercially available PVB and Nylon films. The effects of temperature, humidity, and period of storage on the response of these films were studied in the range from -5 to 60° C and from 11.8 to 96.6% r.h. for up to four months between irradiation and spectral analysis, and within nominal experimental uncertainty (≈ 10%), we found that all the radiochromic films studied can be stored for extended periods under steady-state conditions in the temperature range from -5 to 30° C and from 11.8-75.6% r.h. without correction factors for instability, but under extreme conditions of moisture at elevated temperatures the radiochromic image showed a fading effect on storage.

  1. Quantum mechanical theory of collisional ionization in the presence of intense laser radiation

    Science.gov (United States)

    Bellum, J. C.; George, T. F.

    1978-01-01

    The paper presents a quantum mechanical formalism for treating ionizing collisions occurring in the presence of an intense laser field. Both the intense laser radiation and the internal electronic continuum states associated with the emitted electrons are rigorously taken into account by combining discretization techniques with expansions in terms of electronic-field representations for the quasi-molecule-plus-photon system. The procedure leads to a coupled-channel description of the heavy-particle dynamics which involves effective electronic-field potential surfaces and continua. It is suggested that laser-influenced ionizing collisions can be studied to verify the effects of intense laser radiation on inelastic collisional processes. Calculation procedures for electronic transition dipole matrix elements between discrete and continuum electronic states are outlined.

  2. Technical specifications manual for the MARK-1 pulsed ionizing radiation detection system. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, R.S.; Harker, Y.D.; Jones, J.L.; Hoggan, J.M.

    1993-03-01

    The MARK-1 detection system was developed by the Idaho National Engineering Laboratory for the US Department of Energy Office of Arms Control and Nonproliferation. The completely portable system was designed for the detection and analysis of intense photon emissions from pulsed ionizing radiation sources. This manual presents the technical design specifications for the MARK-1 detection system and was written primarily to assist the support or service technician in the service, calibration, and repair of the system. The manual presents the general detection system theory, the MARK-1 component design specifications, the acquisition and control software, the data processing sequence, and the system calibration procedure. A second manual entitled: Volume 2: Operations Manual for the MARK-1 Pulsed Ionizing Radiation Detection System (USDOE Report WINCO-1108, September 1992) provides a general operational description of the MARK-1 detection system. The Operations Manual was written primarily to assist the field operator in system operations and analysis of the data.

  3. Characterization of Tandem systems of commercial ionization chambers for radiation dosimetry (radiotherapy level)

    CERN Document Server

    Galhardo, E P

    1998-01-01

    The use of X rays for radiotherapy purposes is of great importance for Medicine, and it is necessary to control periodically the performance of the ionization chambers and the radiation beams in order to obtain the best results. The verification of the beam characteristics is made by using standard dosimetry procedures which include the determination of the half-value layers and the exposure rates or the absorbed dose rates in air. Several Tandem systems were set up and tested, using commercial ionization chambers in the energy interval from 14 up to 130 KeV at the Instrumentation Calibration Laboratory of IPEN and at other three institutions, in substitution to the routine conventional procedure of determination of half-value layers using absorbers. The obtained results show the usefulness of these Tandem system for the routine dosimetric procedures of radiotherapy X radiation beams.

  4. Hypergravity modifies the signal transduction of ionizing radiation through p53

    Energy Technology Data Exchange (ETDEWEB)

    Okaichi, Kumio; Usui, Aya; Okumura, Yutaka [Nagasaki Univ. (Japan). Atomic Disease Inst.; Ohnishi, Takeo [Nara Medical Univ., Kashihara (Japan)

    2002-12-01

    To determine the possible effect of hypergravity to modify the signal transduction of ionizing radiation, we analyzed the accumulation of p53 and the expression of p53-dependent genes, Waf-1 and Bax, using the western blot analysis. Hypergravity (20 x g) induced the accumulation of p53 in the human glioblastoma cell line A172 after 3 h of incubation. Low-dose (0.5 Gy) irradiation to the cells accumulated p53 1.5 h after irradiation, and induced Waf-1 and Bax. Under the condition of hypergravity (20 x g), the peak of p53 accumulation was shifted from 1.5 h to 3 h after irradiation, and the inductions of Waf-1 and Bax were suppressed entirely. These results indicate that hypergravity modifies the signal transduction of ionizing radiation through p53 in the cells. (author)

  5. Synergistic effect of phenformin in non-small cell lung cancer (NSCLC) ionizing radiation treatment.

    Science.gov (United States)

    Wang, Jia; Xia, Shi'an; Zhu, Zhizhen

    2015-03-01

    Biguanides, used for anti-diabetic drugs, bring more attention in cancer research for their beneficial effects. Phenformin is more potent than metformin. However its potential application as a anti-cancer regent is far behind metformin. In order to investigate any beneficial effect of combination of Phenformin and radiotherapy, non-small cell lung cancer cell lines A549 and H1299 were exposure under different dose of ionizing radiation with or without Phenformin. Results indicated Phenformin showed synergistic effect and could induce more cancer cell apoptosis and inhibition of tumor growth compared with ionizing radiation alone. Furthermore, this synergistic effect may be through different pathway according to cancer cell genotype background. Our results showed Phenformin induced AMPK activation in A549 but not H1299. However, Phenformin activated eIF2α in both cell lines. Our findings implicated Phenformin may be used as radiosensitizer for non-small cell lung cancer therapy.

  6. Synergistic effect of ionizing radiation on chemical disinfectant treatments for reduction of natural microflora on seafood

    Science.gov (United States)

    Kim, Hyunjoo; Ha, Ji-Hyoung; Lee, Ju-Woon; Jo, Cheorun; Ha, Sang-Do

    2012-08-01

    The purpose of this study was to determine whether combined treatments would produce synergistic disinfection effects on seafood products such as mussel and squid compared with single treatments. We investigated the bactericidal effects of chlorine and ionizing radiation on the natural microflora of mussel and squid. Total aerobic bacteria initially ranged from 102 to 104 Log CFU/g. More than 100 ppm of chlorine and irradiation at 1 kGy were sufficient to reduce the total aerobic bacteria on mussel and squid to a level lower than detection limit (10 CFU/g). Synergistic effects against natural microflora were observed for all combined treatment. These results suggest that a significant synergistic benefit results from combine chlorine-ionizing radiation treatment against natural microflora on mussel and squid.

  7. A novel method involving Matlab coding to determine the distribution of a collimated ionizing radiation beam

    Science.gov (United States)

    Ioan, M.-R.

    2016-08-01

    In ionizing radiation related experiments, precisely knowing of the involved parameters it is a very important task. Some of these experiments are involving the use of electromagnetic ionizing radiation such are gamma rays and X rays, others make use of energetic charged or not charged small dimensions particles such are protons, electrons, neutrons and even, in other cases, larger accelerated particles such are helium or deuterium nuclei are used. In all these cases the beam used to hit an exposed target must be previously collimated and precisely characterized. In this paper, a novel method to determine the distribution of the collimated beam involving Matlab coding is proposed. The method was implemented by using of some Pyrex glass test samples placed in the beam where its distribution and dimension must be determined, followed by taking high quality pictures of them and then by digital processing the resulted images. By this method, information regarding the doses absorbed in the exposed samples volume are obtained too.

  8. Monolithic Silicon Photodetector - Detector of Ionizing Radiation Based on Functional Integrated MOS Structures

    Directory of Open Access Journals (Sweden)

    S.A. Legotin

    2014-07-01

    Full Text Available This paper describes the principle of operation, construction, architecture and fabrication of a new type of monolithic silicon coordinate photodetector - detector of optical and ionizing radiation (MSCP on the basis of functional integrated MOS structures. The analytical estimation of electrophysical characteristics MSCP is given. It is shown that MSCP is a specialized monolithic silicon VLSI containing two-dimensional pixel array with high and low voltage functionally integrated structures (FIS and peripheral electronic circuits of amplification and signal processing matrix. Estimations and presents comparative characteristics are presented. They show potential MSCP possibilities for registration of optical and ionizing radiation. Experimental results of α-particles and electrons registration. The possible areas of application, with the possibility of its use in a wide X-ray panels medical supplies, X-rays, etc are considered.

  9. Radiation Pressure Confinement -- III. The origin of the broad ionization distribution in AGN outflows

    CERN Document Server

    Stern, Jonathan; Laor, Ari; Baskin, Alexei; Holczer, Tomer

    2014-01-01

    The winds of ionized gas driven by Active Galactic Nuclei (AGN) can be studied through absorption features in their X-ray spectra. A recurring feature of these outflows is their broad ionization distribution, including essentially all ionization levels (e.g., Fe^0+ to Fe^25+). The absorption measure distribution (AMD) is defined as the distribution of column density with ionization parameter |dN / dlog xi|. The AMD extends over a wide range of 0.1 < xi < 10^4 (cgs), and is remarkably similar in different objects. Power-law fits to the observed AMDs (|dN / dlog xi| ~ N_1 xi^a) yield N_1 = 3x10^21 cm^-2 +- 0.4 dex and a = 0 -- 0.4. What is the source of this broad ionization distribution, and what sets the small range of observed $N_1$ and $a$ values? A common interpretation is a multiphase outflow, with a wide range of gas densities in a uniform pressure medium. However, it has already been shown that the incident radiation pressure leads to a gas pressure gradient in the photoionized gas, and therefore ...

  10. Improvements to the Ionizing Radiation Risk Assessment Program for NASA Astronauts

    Science.gov (United States)

    Semones, E. J.; Bahadori, A. A.; Picco, C. E.; Shavers, M. R.; Flores-McLaughlin, J.

    2011-01-01

    To perform dosimetry and risk assessment, NASA collects astronaut ionizing radiation exposure data from space flight, medical imaging and therapy, aviation training activities and prior occupational exposure histories. Career risk of exposure induced death (REID) from radiation is limited to 3 percent at a 95 percent confidence level. The Radiation Health Office at Johnson Space Center (JSC) is implementing a program to integrate the gathering, storage, analysis and reporting of astronaut ionizing radiation dose and risk data and records. This work has several motivations, including more efficient analyses and greater flexibility in testing and adopting new methods for evaluating risks. The foundation for these improvements is a set of software tools called the Astronaut Radiation Exposure Analysis System (AREAS). AREAS is a series of MATLAB(Registered TradeMark)-based dose and risk analysis modules that interface with an enterprise level SQL Server database by means of a secure web service. It communicates with other JSC medical and space weather databases to maintain data integrity and consistency across systems. AREAS is part of a larger NASA Space Medicine effort, the Mission Medical Integration Strategy, with the goal of collecting accurate, high-quality and detailed astronaut health data, and then securely, timely and reliably presenting it to medical support personnel. The modular approach to the AREAS design accommodates past, current, and future sources of data from active and passive detectors, space radiation transport algorithms, computational phantoms and cancer risk models. Revisions of the cancer risk model, new radiation detection equipment and improved anthropomorphic computational phantoms can be incorporated. Notable hardware updates include the Radiation Environment Monitor (which uses Medipix technology to report real-time, on-board dosimetry measurements), an updated Tissue-Equivalent Proportional Counter, and the Southwest Research Institute

  11. Exposure to ionizing radiation induced persistent gene expression changes in mouse mammary gland

    Directory of Open Access Journals (Sweden)

    Datta Kamal

    2012-12-01

    Full Text Available Abstract Background Breast tissue is among the most sensitive tissues to the carcinogenic actions of ionizing radiation and epidemiological studies have linked radiation exposure to breast cancer. Currently, molecular understanding of radiation carcinogenesis in mammary gland is hindered due to the scarcity of in vivo long-term follow up data. We undertook this study to delineate radiation-induced persistent alterations in gene expression in mouse mammary glands 2-month after radiation exposure. Methods Six to eight week old female C57BL/6J mice were exposed to 2 Gy of whole body γ radiation and mammary glands were surgically removed 2-month after radiation. RNA was isolated and microarray hybridization performed for gene expression analysis. Ingenuity Pathway Analysis (IPA was used for biological interpretation of microarray data. Real time quantitative PCR was performed on selected genes to confirm the microarray data. Results Compared to untreated controls, the mRNA levels of a total of 737 genes were significantly (p Conclusions Exposure to a clinically relevant radiation dose led to long-term activation of mammary gland genes involved in proliferative and metabolic pathways, which are known to have roles in carcinogenesis. When considered along with downregulation of a number of tumor suppressor genes, our study has implications for breast cancer initiation and progression after therapeutic radiation exposure.

  12. Effects of ionizing radiation on proteins in demineralized, lyophilized or frozen human bone

    Energy Technology Data Exchange (ETDEWEB)

    Antebi, Uri; Mathor, Monica B., E-mail: uri@usp.br, E-mail: mathor@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Guimaraes, Rodrigo P., E-mail: clinicaguimaraes@gmail.com [Santa Casa de Sao Paulo (FCM/SCSP), Sao Paulo, SP (Brazil). Faculdade de Ciencias Medicas

    2015-07-01

    The aim is the study of the application of ionizing radiation (gamma and electron) as sterilizing agents at doses of 15 kGy, 25 kGy and 50 kGy, the demineralized bone tissue frozen and freeze-dried for use in transplants. Five human femoral diaphysis of different donors demineralized bone tissues were preserved as lyophilized or frozen at - 80 deg C. The samples were divided into non-irradiated groups (control) and irradiated by gamma rays or electron beam. The bone proteins were extracted and used to determine the concentrations of total protein, BMP 2 and 7. It was observed a decrease in total protein concentrations, and BMP 2 and 7. The decrease in total protein concentrations, as compared to respective control groups was significant in the lyophilized and frozen samples irradiated at a dose of 50 kGy gamma radiation and beam electrons with greater than 30% reduction. The significant decrease in the levels of BMP 2 and 7 were also observed in higher doses and especially by electron beam. The reductions in the concentrations of total protein and osteoinductive proteins (BMP 2 and 7), were related to the radiation dose, i.e., increase with higher doses of ionizing radiation type and the type of preservation of the bones. The largest reductions in concentrations were observed in bone irradiated by electron beam and at a dose of 50 kGy. But this type of radiation and this high dose are not usual practice for the sterilization of bone tissue. Keywords: demineralized bone tissue, ionizing radiation, Tissue Bank, BMP 2, BMP 7, bone proteins. (author)

  13. 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.

  14. Effect of Ionizing Radiation on Prostaglandins and Gastric Secretion in Rhesus Monkeys

    Science.gov (United States)

    1985-01-01

    gastric electrical control activity when gastric serosal electrodes are used in conjunction with skin electrodes (16,17). Each tracing was examined blindly...damage to gastric mucosal cells, to the myenteric plexus, or the smooth muscle similar to the one observed during the late postirradiation period (5). In...F: ---------- EFFECT OF IONIZING RADIATION ON PROSTAGLANDINS AND GASTRIC SECRETION IN RHESUS MONKS Andre Dubois Etienne Danquechin Dorval Linda Steel

  15. Portable meter study of ionizing radiation Teletector in high rates of air kerma

    Energy Technology Data Exchange (ETDEWEB)

    Damatto, Willian Behling; Potiens, Maria da Penha A.; Vivolo, Vitor, E-mail: willbdamatto@gmail.com [Instituto de Pesquisas Energeticas e Nucleres (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    A set of portable meters of ionizing radiation high rates of air kerma (teletectors) commonly used in emergencies in Brazil and sent to the Calibration Laboratory of IPEN were under several tests and analyst is parameters for the detectors behavior were established. Applied tests were: energy dependence and primarily overload with the new irradiation system. Thus it was possible to determine the most common characteristic found in these equipment (quality control programs) and new calibration criteria were established following international recommendations. (author)

  16. Thermoregulated Nitric Cryosystem for Cooling Gas-Filled Detectors of Ionizing Radiation

    Directory of Open Access Journals (Sweden)

    Zharkov I.P.

    2015-09-01

    Full Text Available Cryosystem for cooling and filling of gas-filled detectors of ionizing radiation with compressed inert gas on the basis of wide-nitrogen cryostat, which provides detetector temperature control in a range of 173 — 293 K and its stabilization with accuracy of ± 1°. The work was carried out within the Ukraine — NATO Program of Collaboration, Grant SfP #984655.

  17. About particular use of ionizing radiations; Des usages particuliers des rayonnements ionisants

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-02-01

    Different uses of ionizing radiations are reviewed: tracers techniques, nuclear gauges, dating by carbon 14, silica doping, use of gamma irradiation for the density measurement in civil engineering, use of a electron capture detector to study by gas chromatography chlorinated contaminants in environment, neutron activation as environmental gauge, analysis of lead in paint and pollutants in ground and dusts, help for work of art valuation by x spectrometry. (N.C.)

  18. A role for bioelectric effects in the induction of bystander signals by ionizing radiation?

    Science.gov (United States)

    Mothersill, C; Moran, G; McNeill, F; Gow, M D; Denbeigh, J; Prestwich, W; Seymour, C B

    2007-04-03

    The induction of "bystander effects" i.e. effects in cells which have not received an ionizing radiation track, is now accepted but the mechanisms are not completely clear. Bystander effects following high and low LET radiation exposure are accepted but mechanisms are still not understood. There is some evidence for a physical component to the signal. This paper tests the hypothesis that bioelectric or biomagnetic phenomena are involved. Human immortalized skin keratinocytes and primary explants of mouse bladder and fish skin, were exposed directly to ionizing radiation or treated in a variety of bystander protocols. Exposure of cells was conducted by shielding one group of flasks using lead, to reduce the dose below the threshold of 2mGy (60)Cobalt gamma rays established for the bystander effect. The endpoint for the bystander effect in the reporter system used was reduction in cloning efficiency (RCE). The magnitude of the RCE was similar in shielded and unshielded flasks. When cells were placed in a Faraday cage the magnitude of the RCE was less but not eliminated. The results suggest that liquid media or cell-cell contact transmission of bystander factors may be only part of the bystander mechanism. Bioelectric or bio magnetic fields may have a role to play. To test this further, cells were placed in a Magnetic Resonance Imaging (MRI) machine for 10 min using a typical head scan protocol. This treatment also induced a bystander response. Apart from the obvious clinical relevance, the MRI results further suggest that bystander effects may be produced by non-ionizing exposures. It is concluded that bioelectric or magnetic effects may be involved in producing bystander signaling cascades commonly seen following ionizing radiation exposure.

  19. Influence of ionizing radiation on the mechanical properties of BisGMA/TEGDMA based experimental resin

    Science.gov (United States)

    LMP, Campos; Boaro, LC; LKG, Santos; Parra, DF; Lugão, AB

    2015-10-01

    Dental restorative composites are activated by visible light and the polymerization process, known as direct technique, is initiated by absorbing light in a specific wavelength range (450-500 nm). However this technique presented some disadvantages. If light is not inserted correctly, layers uncured can cause countless damage to restoration, especially with regard to mechanical properties. A clinical alternative used to reduce the shortcomings of direct application is the use of composite resins for indirect application. These composites are adaptations of resins prepared for direct use, with differences mainly in the healing process. Besides the traditional photoactivation, indirect application composites may be submitted to particular curing conditions, such as a slow curing rate, heating, vacuum, and inert-gas pressure leading to an oxygen-free environment. However few studies have been conducted on the process of post-curing by ionizing radiation at low doses. On this sense the purpose of this study was to evaluate possible interactions of ionizing radiation in the post-curing process of the experimental composites based on BisGMA/TEGDMA filled with silica Aerosil OX-50 silanized. Characterization of the experimental composites was performed by thermogravimetry analysis, infrared spectroscopy, elastic modulus and flexural strength. Statistical analysis of results was calculated by one-way ANOVA/Tukey's test. Cross-linking of the polymeric matrix caused by ionizing radiation, influenced the thermal stability of irradiated specimens. FTIR analysis showed that the ionizing radiation induced a post-cure reaction in the specimens. The irradiation dose influenced directly the mechanical properties that showed a strong positive correlation between flexural strength and irradiation and between modulus strength and irradiation.

  20. Concomitant treatment of F98 glioma cells with new liposomal platinum compounds and ionizing radiation

    OpenAIRE

    Charest, Gabriel; Paquette, Benoit; Fortin, David; Mathieu, David; Sanche, Léon

    2009-01-01

    Despite significant advances, the radiotherapy and chemotherapy protocols marginally improve the overall survival of patients with glioblastoma. Lipoplatin™, and Lipoxal™, the liposomal formulations of cisplatin and oxaliplatin respectively, were tested on the F98 glioma cells for their ability to improve the cell uptake and increase the synergic effect when combined with ionizing radiation. The cytotoxicity and synergic effect of platinum compounds were assessed by colony formation assay, wh...

  1. Backscattered radiation into a transmission ionization chamber: measurement and Monte Carlo simulation.

    Science.gov (United States)

    Yoshizumi, Maíra T; Yoriyaz, Hélio; Caldas, Linda V E

    2010-01-01

    Backscattered radiation (BSR) from field-defining collimators can affect the response of a monitor chamber in X-radiation fields. This contribution must be considered since this kind of chamber is used to monitor the equipment response. In this work, the dependence of a transmission ionization chamber response on the aperture diameter of the collimators was studied experimentally and using a Monte Carlo (MC) technique. According to the results, the BSR increases the chamber response of over 4.0% in the case of a totally closed collimator and 50 kV energy beam, using both techniques. The results from Monte Carlo simulation confirm the validity of the simulated geometry.

  2. SEM analysis of ionizing radiation effects in linear integrated circuits. [Scanning Electron Microscope

    Science.gov (United States)

    Stanley, A. G.; Gauthier, M. K.

    1977-01-01

    A successful diagnostic technique was developed using a scanning electron microscope (SEM) as a precision tool to determine ionization effects in integrated circuits. Previous SEM methods radiated the entire semiconductor chip or major areas. The large area exposure methods do not reveal the exact components which are sensitive to radiation. To locate these sensitive components a new method was developed, which consisted in successively irradiating selected components on the device chip with equal doses of electrons /10 to the 6th rad (Si)/, while the whole device was subjected to representative bias conditions. A suitable device parameter was measured in situ after each successive irradiation with the beam off.

  3. A Monolithic active pixel sensor for ionizing radiation using a 180nm HV-SOI process

    OpenAIRE

    Hemperek, Tomasz; Kishishita, Tetsuichi; Krüger, Hans; Wermes, Norbert

    2014-01-01

    An improved SOI-MAPS (Silicon On Insulator Monolithic Active Pixel Sensor) for ionizing radiation based on thick-film High Voltage SOI technology (HV-SOI) has been developed. Similar to existing Fully Depleted SOI-based (FD-SOI) MAPS, a buried silicon oxide inter-dielectric (BOX) layer is used to separate the CMOS electronics from the handle wafer which is used as a depleted charge collection layer. FD-SOI MAPS suffer from radiation damage such as transistor threshold voltage shifts due to ch...

  4. 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.

  5. Simulated Space Radiation: Impact of Four Different Types of High-Dose Ionizing Radiation on the Lichen Xanthoria elegans

    Science.gov (United States)

    Brandt, Annette; Meeßen, Joachim; Jänicke, Reiner U.; Raguse, Marina; Ott, Sieglinde

    2017-02-01

    This study addresses the viability of the lichen Xanthoria elegans after high-dose ionizing irradiation in the frame of the STARLIFE campaign. The first set of experiments was intended to resemble several types of galactic cosmic radiation (GCR) as present beyond the magnetic shield of Earth. In the second set of experiments, γ radiation up to 113 kGy was applied to test the limit of lichen resistance to ionizing radiation. Entire thalli of Xanthoria elegans were irradiated in the anhydrobiotic state. After STARLIFE 1, the metabolic activity of both symbionts was quantified by live/dead staining with confocal laser scanning microscopy. The photosynthetic activity was measured after the respective irradiation to assess the ability of the symbiotic green algae to restore photosynthesis after irradiation. The STARLIFE campaign complements the results of the LIFE experiments at the EXPOSE-E facility on the International Space Station by testing the model organism Xanthoria elegans on its resistance to hazardous radiation that might be accumulated during long-term space exposure. In addition, the photosynthetic activity of metabolically active lichen was investigated after X-ray irradiation up to 100 Gy (3.3 Gy/min). Since previous astrobiological experiments were mostly performed with anhydrobiotic lichen, these experiments will broaden our knowledge on the correlation of physiological state and astrobiological stressors.

  6. Modeling hematopoietic system response caused by chronic exposure to ionizing radiation.

    Science.gov (United States)

    Akushevich, Igor V; Veremeyeva, Galina A; Dimov, Georgy P; Ukraintseva, Svetlana V; Arbeev, Konstantin G; Akleyev, Alexander V; Yashin, Anatoly I

    2011-05-01

    A new model of the hematopoietic system response in humans chronically exposed to ionizing radiation describes the dynamics of the hematopoietic stem cell compartment as well as the dynamics of each of the four blood cell types (lymphocytes, neutrophiles, erythrocytes, and platelets). The required model parameters were estimated based on available results of human and experimental animal studies. They include the steady-state number of hematopoietic stem cells and peripheral blood cell lines in an unexposed organism, amplification parameters for each blood line, parameters describing proliferation and apoptosis, parameters of feedback functions regulating the steady-state numbers, and characteristics of radiosensitivity related to cell death and non-lethal cell damage. The model predictions were tested using data on hematological measurements (e.g., blood counts) performed in 1950-1956 in the Techa River residents chronically exposed to ionizing radiation since 1949. The suggested model of hematopoiesis is capable of describing experimental findings in the Techa River Cohort, including: (1) slopes of the dose-effect curves reflecting the inhibition of hematopoiesis due to chronic ionizing radiation, (2) delay in effect of chronic exposure and accumulated character of the effect, and (3) dose-rate patterns for different cytopenic states (e.g., leukopenia, thrombocytopenia).

  7. When theory and observation collide: Can non-ionizing radiation cause cancer?

    Science.gov (United States)

    Havas, Magda

    2017-02-01

    This paper attempts to resolve the debate about whether non-ionizing radiation (NIR) can cause cancer-a debate that has been ongoing for decades. The rationale, put forward mostly by physicists and accepted by many health agencies, is that, "since NIR does not have enough energy to dislodge electrons, it is unable to cause cancer." This argument is based on a flawed assumption and uses the model of ionizing radiation (IR) to explain NIR, which is inappropriate. Evidence of free-radical damage has been repeatedly documented among humans, animals, plants and microorganisms for both extremely low frequency (ELF) electromagnetic fields (EMF) and for radio frequency (RF) radiation, neither of which is ionizing. While IR directly damages DNA, NIR interferes with the oxidative repair mechanisms resulting in oxidative stress, damage to cellular components including DNA, and damage to cellular processes leading to cancer. Furthermore, free-radical damage explains the increased cancer risks associated with mobile phone use, occupational exposure to NIR (ELF EMF and RFR), and residential exposure to power lines and RF transmitters including mobile phones, cell phone base stations, broadcast antennas, and radar installations.

  8. Instrumentation for characterizing materials and composed semiconductors for ionizing radiation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Paschoal, Arquimedes J.A.; Leite, Adolfo M.B.; Nazzre, Fabio V.B.; Santos, Luiz A.P. [Centro Regional de Ciencias Nucleares (CRCN/CNEN-PE), Recife, PE (Brazil). Lab. de Instrumentacao Nuclear]. E-mail: lasantos@cnen.gov.br

    2007-07-01

    The purpose of this work is the development of instrumentation for characterizing some type of ionizing radiation detectors. Those detectors are being manufactured by the Nuclear Instrumentation Laboratory at CRCN/Recife and can be used both on photon beam and with particles. Such detectors consist of semiconductor material in the form of films generated by oxide growing or by means of semiconductor material deposition in a substrate. Those materials can be made of metals, semi-metals, composites or semiconductor polymers. Prior to expose those detectors to ionizing radiation, it must be physically and electrically characterized. In this intention it was developed an electromechanical system. An electrical circuit was built to measure the signal from the detector and another circuit to control the movement of four probes (4-points technique) by using a stepper motor and the micro stepping technique avoiding damage to the detector. This system can be of interest to researchers that work with a sort of semiconductor materials in the form of thin film and in nanotechnological processes aiming the design of radiation ionizing detectors. (author)

  9. Influence of solvothermal synthesis conditions in BiSI nanostructures for application in ionizing radiation detectors

    Science.gov (United States)

    Aguiar, I.; Mombrú, M.; Pérez Barthaburu, M.; Bentos Pereira, H.; Fornaro, L.

    2016-02-01

    BiSI belongs to the A V B VI C VII chalcohalides group of compounds. These compounds show several interesting properties such as ferroelectricity, piezoelectricity along the c axis, and photoconductivity. Moreover, BiSI is a potential semiconductor material for room-temperature gamma and x-ray detection, given its band gap of 1.57 eV and its high density, 6.41 g cm-3. In this work we present BiSI nanostructures synthesized by the solvothermal method with the intention of using them for ionizing radiation detection. The solvent was varied to study its influence in morphology, particle size and size distribution. Three different conditions were tested, using either water, monoethylene glycol and a mixture of both solvents. Nanostructures were characterized by XRD to determine the phase obtained and reaction completeness; TEM was used to observe nanostructures morphology, size, size distribution and crystallinity; and finally FT-IR diffuse reflectance was used to study monoethylene glycol presence in the samples. Nanorods in the range of 100-200 nm width were obtained in all samples, but round nanoparticles of around 10 nm in diameter were also detected in samples synthesized only with monoethylene glycol. Samples synthesized in monoethylene glycol were used to fabricate pellets to construct detectors. The detectors responded to ionizing radiation and a resistivity in the order of 1013 Ω cm was estimated. This work proposes, to our knowledge, the first study of BiSI for its application in ionizing radiation detection.

  10. Effect of ionizing radiation on some quality attributes of nutraceutically valued lotus seeds.

    Science.gov (United States)

    Bhat, Rajeev; Karim, A A

    2009-01-01

    Radiation processing has been employed successfully for value addition of food and agricultural products. Preliminary studies were undertaken to evaluate the changes induced by ionizing radiation (up to 30 kGy), in the form of gamma irradiation and electron beam irradiation, on some quality attributes and nutritive values of nutraceutically valued lotus seeds. Significant loss in seed firmness was recorded between control and irradiated seeds, irrespective of radiation source. Similarly, the specific viscosity of irradiated lotus seeds decreased significantly up to a dose of 7.5 kGy. Starch increased after exposure to gamma or electron beam irradiation, whereas the total phenolic contents were decreased. Gamma irradiation revealed an enhancement in protein, while the electron beam showed a decrease. Partial oxidation of the seeds during radiation treatments might have occurred as evidenced from the decomposition profiles (thermogravimetry) during heating. It is evident that ionizing radiation brought about significant and variable changes in the quality and nutritive values of lotus seed. Further exploration of this technology for safety and quality is warranted.

  11. The Influence of Ionizing Radiation on Exosome Composition, Secretion and Intercellular Communication.

    Science.gov (United States)

    Jelonek, Karol; Widlak, Piotr; Pietrowska, Monika

    2016-01-01

    A large variety of vesicles is actively secreted into the extracellular space by most type of cells. The smallest nanoparticles (30-120 nm), called exosomes, are known to transport their cargo (nucleic acids, proteins and lipids) between diverse locations in the body. Specific content of exosomes and their influence on recipient cells depends primarily on the type of the secretory (donor) cell, yet several studies highlight the importance of environmental stress on which the donor cells are exposed. Ionizing radiation, which induces damage to DNA and other structures of a target cell, is one of well-recognized stress conditions influencing behavior of affected cells. A few recent studies have evidenced radiationinduced changes in composition of exosomes released from irradiated cells and their involvement in radiation-related communication between cells. Inducible pathways of exosome secretion activated in irradiated cells are regulated by TSAP6 protein (the transmembrane protein tumor suppressor-activated pathway 6), which is transcriptionally regulated by p53, hence cellular status of this major DNA damage response factor affects composition and secretion rate of exosomes released from target cells. Moreover, exosomes released from irradiated cells have been shown to mediate the radiation-induced bystander effect. Understanding radiation-related mechanisms involved in exosome formation and "makeup" of their cargo would shed light on the role of exosomes in systemic response of cells, tissues and organisms to ionizing radiation which may open new perspectives in translational medicine and anticancer-treatment.

  12. Risks of exposure to ionizing and millimeter-wave radiation from airport whole-body scanners.

    Science.gov (United States)

    Moulder, John E

    2012-06-01

    Considerable public concern has been expressed around the world about the radiation risks posed by the backscatter (ionizing radiation) and millimeter-wave (nonionizing radiation) whole-body scanners that have been deployed at many airports. The backscatter and millimeter-wave scanners currently deployed in the U.S. almost certainly pose negligible radiation risks if used as intended, but their safety is difficult-to-impossible to prove using publicly accessible data. The scanners are widely disliked and often feared, which is a problem made worse by what appears to be a veil of secrecy that covers their specifications and dosimetry. Therefore, for these and future similar technologies to gain wide acceptance, more openness is needed, as is independent review and regulation. Publicly accessible, and preferably peer-reviewed evidence is needed that the deployed units (not just the prototypes) meet widely-accepted safety standards. It is also critical that risk-perception issues be handled more competently.

  13. Radon in the Workplace: the Occupational Safety and Health Administration (OSHA) Ionizing Radiation Standard.

    Science.gov (United States)

    Lewis, Robert K

    2016-10-01

    On 29 December 1970, the Occupational Safety and Health Act of 1970 established the Occupational Safety and Health Administration (OSHA). This article on OSHA, Title 29, Part 1910.1096 Ionizing Radiation standard was written to increase awareness of the employer, the workforce, state and federal governments, and those in the radon industry who perform radon testing and radon mitigation of the existence of these regulations, particularly the radon relevant aspect of the regulations. This review paper was also written to try to explain what can sometimes be complicated regulations. As the author works within the Radon Division of the Pennsylvania Department of Environmental Protection, Bureau of Radiation Protection, the exclusive focus of the article is on radon. The 1910.1096 standard obviously covers many other aspects of radiation and radiation safety in the work place.

  14. Organization of central database for implementation of ionizing radiation protection in the Republic of Croatia

    Energy Technology Data Exchange (ETDEWEB)

    Kubelka, D.; Svilicic, N. [Croatian Radiation Protection Institute, Zagreb (Croatia)

    2000-05-01

    The paper is intended to give an overview of the situation in the Republic of Croatia resulting from passing of the new ionizing radiation protection law. Data collecting organization and records keeping structure will be highlighted in particular, as well as data exchange between individual services involved in ionizing radiation protection. The Radiation Protection Act has been prepared in compliance with the international standards and Croatian regulations governing the ionizing radiation protection field. Its enforcement shall probably commence in October 1999, when the necessary bylaws regulating in detail numerous specific and technical issues of particular importance for ionizing radiation protection implementation are expected to be adopted. Within the Croatian Government, the Ministry of Health is charge of ionizing radiation protection. Such competence is traditional in our country and common throughout the world. This Ministry has authorized three institutions to carry out technical tasks related to the radiation protection, such as radiation sources inspections and personal dosimetry. Such distribution of work demands coordination of all involved institutions, control of their work and records keeping. The Croatian Radiation Protection Institute has been entrusted to coordinate work of these institutions, control their activities, and set up the central national registry of radiation sources and workers, as well as doses received by the staff during their work. Since the Croatian Radiation Protection Institute is a newly established institution, we could freely determine our operational framework. Due to its publicly accessible source code and wide base of users and developers, the best prospective for stability and long-term accessibility is offered by the Linux operating system. For the database development, Oracle RDBMS was used, partly because it is a leading manufacturer of database management systems, and partly because our staff is very familiar

  15. Information on biological health effects of ionizing radiation and radionuclides: the rule of a web site

    Energy Technology Data Exchange (ETDEWEB)

    Comte, A.; Gaillard-Lecanu, E.; Flury-Herard, A. [CEA Fontenay aux Roses, 92 (France); Ourly, F. [CEA Saclay, 91 - Gif sur Yvette (France); Hemidy, P.; Lallemand, J. [Electricite de France (EDF), Service de Radioprotection, 75 - Paris (France)

    2006-07-01

    The purpose of this project is to provide a source of information on biological and health effects of radionuclides and ionizing radiation in an easy to use format. Reported work is made up of two distinct parts: data sheets for selected radionuclides and a web file. Data sheets: Specific radiation data sheets provide an overview of the properties, the environmental behaviour, the different pathways of human exposure and the biological and health consequences of selected radionuclides. Radionuclides that have been selected are those commonly dealt with in nuclear industry (and in other areas such as medicine) and released to the environment or naturally occurring (plutonium, tritium, carbon 14). Data sheets corresponding to the different radionuclides are based on the main sources of scientific information in dosimetry, epidemiology, radiobiology and radiation protection. These data sheets are intended for radiation protection specialists and physicians. They include: main physical and chemical characteristics, main radiation protection data: dose coefficients (public, workers), dose limits sources, total released estimate (nuclear industry, atmospheric tests, main pathway of human exposure and biological behaviour, biological and health effects, medical supervision, treatment a list of the main references, appendix providing accurate information. Web file: http://www-dsv.cea.fr/doc/carmin{sub e}xt/fond.php This web file provides a source of information on biological and health effects of ionizing radiation and biological basic knowledge of radiation protection. Available for consultation via Internet, compiled information provides, in a same file, subjects as varied as biological mechanisms, ionizing radiations action, biological and health effects, risk assessment This file is mainly intended to assist in informing and training of non-specialist readership (students, teaching on radiation protection basic knowledge. This electronic document is divided in three

  16. Ionizing radiation effects on ISS ePTFE jacketed cable assembly

    Science.gov (United States)

    Koontz, S. L.; Golden, J. L.; Lorenz, M. J.; Pedley, M. D.

    2003-09-01

    Polytetrafluoroethylene (PTFE), which is susceptible to embrittlement by ionizing radiation, is used as a primary material in the Mobile Transporter's (MT) Trailing Umbilical System (TUS) cable on the International Space Station (ISS). The TUS cable provides power and data service between the ISS truss and the MT. The TUS cable is normally stowed in an uptake reel and is fed out to follow the MT as it moves along rails on the ISS truss structure. For reliable electrical and mechanical performance, TUS cable polymeric materials must be capable of >3.5% elongation without cracking or breaking. The MT TUS cable operating temperature on ISS is expected to range between -100°C and +130°C. The on-orbit functional life requirement for the MT TUS cable is 10 years. Analysis and testing were performed to verify that the MT TUS cable would be able to meet full-life mechanical and electrical performance requirements, despite progressive embrittlement by the natural ionizing radiation environment. Energetic radiation belt electrons (trapped electrons) are the principal contributor to TUS cable radiation dose. TUS cable specimens were irradiated, in vacuum, with both energetic electrons and gamma rays. Electron beam energy was chosen to minimize charging effects on the non-conductive ePTFE (expanded PTFE) targets. Tensile testing was then performed, over the expected range of operating temperatures, as a function of radiation dose. When compared to the expected in-flight radiation dose/depth profile, atomic oxygen (AO) erosion of the radiation damaged TUS cable jacket surfaces is more rapid than the development of radiation induced embrittlement of the same surfaces. Additionally, the layered construction of the jacket prevents crack growth propagation, leaving the inner layer material compliant with the design elongation requirements. As a result, the TUS cable insulation design was verified to meet performance life requirements.

  17. Ionizing Radiation Detectors Based on Ge-Doped Optical Fibers Inserted in Resonant Cavities

    Directory of Open Access Journals (Sweden)

    Saverio Avino

    2015-02-01

    Full Text Available The measurement of ionizing radiation (IR is a crucial issue in different areas of interest, from environmental safety and industrial monitoring to aerospace and medicine. Optical fiber sensors have recently proven good candidates as radiation dosimeters. Here we investigate the effect of IR on germanosilicate optical fibers. A piece of Ge-doped fiber enclosed between two fiber Bragg gratings (FBGs is irradiated with gamma radiation generated by a 6 MV medical linear accelerator. With respect to other FBG-based IR dosimeters, here the sensor is only the bare fiber without any special internal structure. A near infrared laser is frequency locked to the cavity modes for high resolution measurement of radiation induced effects on the fiber optical parameters. In particular, we observe a variation of the fiber thermo-optic response with the radiation dose delivered, as expected from the interaction with Ge defect centers, and demonstrate a detection limit of 360 mGy. This method can have an impact in those contexts where low radiation doses have to be measured both in small volumes or over large areas, such as radiation therapy and radiation protection, while bare optical fibers are cheap and disposable.

  18. Ionizing and ultraviolet radiation enhances the efficiency of DNA mediated gene transfer in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Perez, C.F.

    1984-08-01

    The enhancement effects of ionizing and non-ionizing radiation on the efficiency of DNA mediated gene transfer were studied. Confluent Rat-2 cells were transfected with purified SV40 viral DNA, irradiated with either X-rays or ultraviolet, trypsinized, plated, and assayed for the formation of foci on Rat-2 monolayers. Both ionizing and ultraviolet radiation enhanced the frequency of A-gene transformants/survivor compared to unirradiated transfected cells. These enhancements were non-linear and dose dependent. A recombinant plasmid, pOT-TK5, was constructed that contained the SV40 virus A-gene and the Herpes Simplex virus (HSV) thymidine kinase (TK) gene. Confluent Rat-2 cells transfected with pOT-TK5 DNA and then immediately irradiated with either X-rays or 330 MeV/amu argon particles at the Berkeley Bevalac showed a higher frequency of HAT/sup +/ colonies/survivor than unirradiated transfected cells. Rat-2 cells transfected with the plasmid, pTK2, containing only the HSV TK-gene were enhanced for TK-transformation by both X-rays and ultraviolet radiation. The results demonstrate that radiation enhancement of the efficiency of DNA mediated gene transfer is not explained by increased nuclear uptake of the transfected DNA. Radiation increases the competence of the transfected cell population for genetic transformation. Three models for this increased competence are presented. The targeted integration model, the inducible recombination model, the partition model, and the utilization of DNA mediated gene transfer for DNA repair studies are discussed. 465 references.

  19. The Effect of High-Dose Ionizing Radiation on the Astrobiological Model Lichen Circinaria gyrosa

    Science.gov (United States)

    de la Torre, Rosa; Zélia Miller, Ana; Cubero, Beatriz; Martín-Cerezo, M. Luisa; Raguse, Marina; Meeßen, Joachim

    2017-02-01

    The lichen Circinaria gyrosa is an astrobiological model defined by its high capacity of resistance to space conditions and to a simulated martian environment. Therefore, it became part of the currently operated BIOMEX experiment on board the International Space Station and the recent STARLIFE campaign to study the effects of four types of space-relevant ionizing radiation. The samples were irradiated with helium and iron ions at doses up to 2 kGy, with X-rays at doses up to 5 kGy and with γ rays at doses from 6 to 113 kGy. Results on C. gyrosa's resistance to simulated space ionizing radiation and its post-irradiation viability were obtained by (i) chlorophyll a fluorescence of photosystem II (PSII), (ii) epifluorescence microscopy, (iii) confocal laser scanning microscopy (CLSM), and (iv) field emission scanning electron microscopy (FESEM). Results of photosynthetic activity and epifluorescence show no significant changes up to a dose of 1 kGy (helium ions), 2 kGy (iron ions), 5 kGy (X-rays) - the maximum doses applied for those radiation qualities - as well as a dose of 6 kGy of γ irradiation, which was the lowest dose applied for this low linear energy transfer (LET) radiation. Significant damage in a dose-related manner was observed only at much higher doses of γ irradiation (up to 113 kGy). These data corroborate the findings of the parallel STARLIFE studies on the effects of ionizing radiation on the lichen Circinaria gyrosa, its isolated photobiont, and the lichen Xanthoria elegans.

  20. Human responses to the threat of or exposure to ionizing radiation at Three Mile Island, Pennsylvania, and Goiania, Brazil.

    Science.gov (United States)

    Collins, Daniel L

    2002-02-01

    The psychological stressors and their aftereffects associated with the Three Mile Island accident, the Goiania, Brazil, cesium-137 accident, and the Abadia, Brazil, storage location are summarized and compared. Cross-cultural comparisons of human responses to ionizing radiation are rare. A multidisciplinary methodological approach to examining the psychological responses to ionizing radiation is even more rare. The psychological, behavioral, neuroendocrine, and cardiovascular results are summarized for Three Mile Island, Goiania, and Abadia.

  1. Bilogical effects of ionizing radiation: epidemiological surveys and laboratory animal experiments. Implications for risk evaluation and decision processes

    Energy Technology Data Exchange (ETDEWEB)

    Fabrikant, J.I.

    1981-04-01

    General background is given for an understanding of the potential health effects in populations exposed to low-level ionizing radiations. The discussion is within the framework of the scientific deliberations and controversies that arose during preparation of the current report of the committee on the biological effects of ionizing radiation of the National Academy of Science - National Research Council (1980 Beir-III Report). (ACR)

  2. Radiation and ionization energy loss simulation for the GDH sum rule experiment in Hall-A at Jefferson Lab

    Institute of Scientific and Technical Information of China (English)

    YAN Xin-Hu; YE Yun-Xiu; CHEN Jian-Ping; LU Hai-Jiang; ZHU Peng-Jia; JIANG Feng-Jian

    2015-01-01

    The radiation and ionization energy loss are presented for single arm Monte Carlo simulation for the GDH sum rule experiment in Hall-A at the Jefferson Lab.Radiation and ionization energy loss are discussed for 12C elastic scattering simulation.The relative momentum ratio-Ap and 12C elastic cross section are compared without and with radiative energy loss and a reasonable shape is obtained by the simulation.The total energy loss distribution is obtained,showing a Landau shape for 12C elastic scattering.This simulation work will give good support for radiation correction analysis of the GDH sum rule experiment.

  3. Sensorial analysis evaluation in cereal bars preserved by ionizing radiation processing

    Science.gov (United States)

    Villavicencio, A. L. C. H.; Araújo, M. M.; Fanaro, G. B.; Rela, P. R.; Mancini-Filho, J.

    2007-11-01

    Gamma-rays utilized as a food-processing treatment to eliminate insect contamination is well established in food industries. Recent troubles in Brazilian cereal bars commercialization require a special consumer's attention because some products were contaminated by insects. To solve the problem, food-irradiation treatment was utilized as a safe and effective solution. The final product was free of insect contamination. The aim of this study was to determine the best radiation dose processing utilized to disinfestations and detect some change on sensorial characteristic by sensorial analysis in cereal bars. In this study, three different kinds of cereal bars were purchased in São Paulo (Brazil) in supermarkets and irradiated with 1.0, 2.0 and 3.0 kGy at "Instituto de Pesquisas Energéticas e Nucleares" (IPEN-CNEN/SP). The samples were treated with ionizing radiation using a 60Co gamma-ray facility (Gammacell 220, A.E.C.L.). That radiation doses were used successfully as an anti-insect treatment in the cereal bars, since in some food industries doses up to 3.0 kGy are used to guarantee at least a dose of 1.0 kGy in internal cereal bars package. Sensorial analysis was necessary since cereal bars contain ingredients very sensitive to ionizing radiation process.

  4. Influence of ionizing radiation on Trypanosoma cruzi; Influencia da radiacao ionizante sobre o Trypanosoma cruzi

    Energy Technology Data Exchange (ETDEWEB)

    Szarota, Rosa Maria

    2006-07-01

    Chagas's disease is one of the major public health problems in South America, promoting high prejudice to the local population. Despite the massive efforts to control it, this disease has no cure and presents puzzling unsolved questions. Considering that many researchers have used ionizing radiation to modify protozoans or biomolecules, we investigated the immunological response aspects of susceptible and resistant mice using irradiated parasites. Low radiation doses preserved the reproductive and invasive capacities of the parasite. Both susceptible and resistant animals, after immunization with irradiated parasites produced specific antibodies. After a challenge, the animals presented low parasitaemia, excepting those immunized with the antigen irradiated with higher doses. Using low radiation doses, we were able to selectively isolate trypomastigotes, leading to an improvement in the quality of the immune response, as previously reported when performing complement system assays. These data highlight the importance of selecting trypomastigote forms for immunization against T. cruz; and point towards ionizing radiation as an alternative to achieve this selection, since when this procedure is performed using complement, the subsequent steps are impaired by the difficulties to remove this component from the system. (author)

  5. The carcinogenic risks of low-LET and high-LET ionizing radiations. Revision

    Energy Technology Data Exchange (ETDEWEB)

    Fabrikant, J.I. [Lawrence Berkeley Lab., CA (United States)]|[California Univ., San Francisco, CA (United States)

    1991-08-01

    This report presents a discussion on risk from ionizing radiations to human populations. Important new information on human beings has come mainly from further follow-up of existing epidemiological studies, notably the Japanese atomic bomb survivors and the ankylosing spondylitis patients; from new epidemiological surveys, such as the patients treated for cancer of the uterine cervix; and from combined surveys, including workers exposed in underground mines. Since the numerous and complex differences among the different study populations introduce factors that influence the risk estimates derived in ways that are not completely understood, it is not clear how to combine the different risk estimates obtained. These factors involve complex biological and physical variables distributed over time. Because such carcinogenic effects occur too infrequently to be demonstrated at low doses, the risks of low-dose radiation can be estimated only by interpolation from observations at high doses on the basis of theoretical concepts, mathematical models and available empirical evidence, primarily the epidemiological surveys of large populations exposed to ionizing radiation. In spite of a considerable amount of research, only recently has there has been efforts to apply the extensive laboratory data in animals to define the dose-incidence relationship in the low dose region. There simply are insufficient data in the epidemiological studies of large human populations to estimate risk coefficients directly from exposure to low doses. The risk estimates for the carcinogenic effects of radiation have been, in the past, somewhat low and reassessment of the numerical values is now necessary.

  6. The carcinogenic risks of low-LET and high-LET ionizing radiations

    Energy Technology Data Exchange (ETDEWEB)

    Fabrikant, J.I. (Lawrence Berkeley Lab., CA (United States) California Univ., San Francisco, CA (United States))

    1991-08-01

    This report presents a discussion on risk from ionizing radiations to human populations. Important new information on human beings has come mainly from further follow-up of existing epidemiological studies, notably the Japanese atomic bomb survivors and the ankylosing spondylitis patients; from new epidemiological surveys, such as the patients treated for cancer of the uterine cervix; and from combined surveys, including workers exposed in underground mines. Since the numerous and complex differences among the different study populations introduce factors that influence the risk estimates derived in ways that are not completely understood, it is not clear how to combine the different risk estimates obtained. These factors involve complex biological and physical variables distributed over time. Because such carcinogenic effects occur too infrequently to be demonstrated at low doses, the risks of low-dose radiation can be estimated only by interpolation from observations at high doses on the basis of theoretical concepts, mathematical models and available empirical evidence, primarily the epidemiological surveys of large populations exposed to ionizing radiation. In spite of a considerable amount of research, only recently has there has been efforts to apply the extensive laboratory data in animals to define the dose-incidence relationship in the low dose region. There simply are insufficient data in the epidemiological studies of large human populations to estimate risk coefficients directly from exposure to low doses. The risk estimates for the carcinogenic effects of radiation have been, in the past, somewhat low and reassessment of the numerical values is now necessary.

  7. The Protective Effect of Curcumin on Ionizing Radiation-induced Cataractogenesis in Rats

    Directory of Open Access Journals (Sweden)

    Fatma Nesrin Turan

    2012-12-01

    Full Text Available Objective: The aim of the study was to determine the protective effect of curcumin against ionizing radiation-induced cataract in the lens of rats. Material and Methods: Rats were divided into six groups. Group 1: Control, Group 2: Dimethyl sulfoxide (DMSO, Group 3: DMSO+curcumin, Group 4: Irradiation, Group 5: Irradiation+DMSO, Group 6: Irradiation+DMSO+curcumin. A 15 Gy total dose was given to 4, 5, 6 groups for radiation damage. Curcumin (100 mg/kg was dissolved in DMSO and given by intragastric intubation for 28 days. At the end of the experiment, lenses were graded and enucleated. The lenticular activity of the antioxidant enzymes, total antioxidant and glutathione peroxidase (GSH-Px, and the malondialdehyde (MDA were measured.Results: 100% Cataract was seen in the irradiation group. Cataract rate fell to 40% and was limited at grade 1 and 2 in the curcumin group. In the irradiation group, antioxidant enzyme levels were decreased, MDA levels were increased. There was an increase in antioxidant enzyme levels and a significant decrease in MDA in the group which was given curcumin.Conclusion: Curcumin has antioxidant and radioprotective properties and is likely to be a valuable agent for protection against ionizing radiation. Hence, it may be used as an antioxidant and radioprotector against radiation-induced cataractogenesis.

  8. POPULATION RADIATION PROTECTION PROVIDING UNDER THE INFLUENCE OF NATURAL IONIZING IRRADIATION SOURCES

    Directory of Open Access Journals (Sweden)

    E. G. Stepanov

    2015-01-01

    Full Text Available An article presents the modern problems of population radiation protection inBashkortostanRepublic. The main natural ionizing irradiation sources are identified and their contribution to the total exposure dose of the BashkortostanRepublicpopulation is analyzed. The types of the main natural ionizing irradiation sources are identified, as well as the ways of their intake and the methods of their influence. The results of laboratory studies are presented for the radon equivalent equilibrium volumetric activity, for the average gamma radiation dose rate in dwellings, for the investigations of gross alpha and gross beta activity in drinking water and open water sourcesBashkortostanRepublic. The article underlines the main problems of the radiation situation in the new construction. The main preventive measures are pointed out for the radiation protection of the buildings under construction improving. The article also presents an analysis of the results of activities of the Administration of Rospotrebnadzor in theBashkortostanRepublicfor the reducing of the levels of the Republican population exposure from the natural irradiation sources.

  9. Sensorial analysis evaluation in cereal bars preserved by ionizing radiation processing

    Energy Technology Data Exchange (ETDEWEB)

    Villavicencio, A.L.C.H. [Instituto de Pesquisas Energeticas e Nucleares-IPEN-CNEN/SP, Centro de Tecnologia das Radiacoes, Lab. de Deteccao de Alimentos Irradiados, Travessa R. No. 400, Cidade Universitaria, CEP 05508-910, Sao Paulo (Brazil)], E-mail: villavic@ipen.br; Araujo, M.M.; Fanaro, G.B.; Rela, P.R. [Instituto de Pesquisas Energeticas e Nucleares-IPEN-CNEN/SP, Centro de Tecnologia das Radiacoes, Lab. de Deteccao de Alimentos Irradiados, Travessa R. No. 400, Cidade Universitaria, CEP 05508-910, Sao Paulo (Brazil); Mancini-Filho, J. [Faculdade de Ciencias Farmaceuticas-FCF/USP, Departamento de Alimentos e Nutricao Experimental, Lab. de Lipides, Sao Paulo (Brazil)], E-mail: jmancini@usp.br

    2007-11-15

    Gamma-rays utilized as a food-processing treatment to eliminate insect contamination is well established in food industries. Recent troubles in Brazilian cereal bars commercialization require a special consumer's attention because some products were contaminated by insects. To solve the problem, food-irradiation treatment was utilized as a safe and effective solution. The final product was free of insect contamination. The aim of this study was to determine the best radiation dose processing utilized to disinfestations and detect some change on sensorial characteristic by sensorial analysis in cereal bars. In this study, three different kinds of cereal bars were purchased in Sao Paulo (Brazil) in supermarkets and irradiated with 1.0, 2.0 and 3.0 kGy at 'Instituto de Pesquisas Energeticas e Nucleares' (IPEN-CNEN/SP). The samples were treated with ionizing radiation using a {sup 60}Co gamma-ray facility (Gammacell 220, A.E.C.L.). That radiation doses were used successfully as an anti-insect treatment in the cereal bars, since in some food industries doses up to 3.0 kGy are used to guarantee at least a dose of 1.0 kGy in internal cereal bars package. Sensorial analysis was necessary since cereal bars contain ingredients very sensitive to ionizing radiation process.

  10. Late effects of ionizing radiation on testis; Effets tardifs des radiations ionisantes sur le testicules

    Energy Technology Data Exchange (ETDEWEB)

    Bardet, E. [Centre Regional de Lutte Contre le Cancer Rene-Gauducheau, 44 - Nantes (France)

    1997-12-01

    Most of the basic data regarding the effect of radiation on the testis are issued from animal studies. They demonstrate the extreme radiosensitivity on the germ cell lineage but little is known about the reversible or definitive aspects of these radiation induced effects. In man, the late non stochastic effects of radiation to the testicle are mainly related to persisting spermatogenesis disturbances or/and hormone related problems. Morphological, physiological, radiobiological specificities of the human testis along with numerous parameters depending on radiation conditions make it difficult to evaluate the late effects and radiation tolerance doses. Evaluation of such effects based on a common scale for therapeutic radiation schedules would improve the present understanding and possibility prevent the occurrence of these delayed effects, for the benefit of patients. (author)

  11. 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

  12. Observation of terahertz-radiation-induced ionization in a single nano island

    Science.gov (United States)

    Seo, Minah; Kang, Ji-Hun; Kim, Hyo-Suk; Hyong Cho, Joon; Choi, Jaebin; Min Jhon, Young; Lee, Seok; Hun Kim, Jae; Lee, Taikjin; Park, Q.-Han; Kim, Chulki

    2015-05-01

    Terahertz (THz) electromagnetic wave has been widely used as a spectroscopic probe to detect the collective vibrational mode in vast molecular systems and investigate dielectric properties of various materials. Recent technological advances in generating intense THz radiation and the emergence of THz plasmonics operating with nanoscale structures have opened up new pathways toward THz applications. Here, we present a new opportunity in engineering the state of matter at the atomic scale using THz wave and a metallic nanostructure. We show that a medium strength THz radiation of 22 kV/cm can induce ionization of ambient carbon atoms through interaction with a metallic nanostructure. The prepared structure, made of a nano slot antenna and a nano island located at the center, acts as a nanogap capacitor and enhances the local electric field by two orders of magnitudes thereby causing the ionization of ambient carbon atoms. Ionization and accumulation of carbon atoms are also observed through the change of the resonant condition of the nano slot antenna and the shift of the characteristic mode in the spectrum of the transmitted THz waves.

  13. Performance of a Roos ionization chamber in gamma radiation beams ({sup 60}Co)

    Energy Technology Data Exchange (ETDEWEB)

    Perini, Ana P.; Neves, Lucio P.; Caldas, Linda V.E., E-mail: lcaldas@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Among the different types of dosimetry instruments, the ionization chambers are the most practical and and important radiation measurement devices due to their high sensitivity and relatively constant response within a wide range of energies. A commercial PTW ionization chamber (Roos electron chamber) usually utilized in X-ray beams, was tested to verify the possibility of its dosimetric application in {sup 60}Co beams. The main tests in this work were: short- and long-term stability, saturation, ion collection efficiency, polarity effect, leakage current and angular dependence. The characterization tests were performed using a Gammatron {sup 60}Co irradiator and a special goniometer made of PMMA. All results were within international recommendations. The reproducibility test presented results within the recommended limit of {+-}1%, and all coefficients of variation observed in the repeatability test were lower than {+-}0.07%. The ion collection efficiency was better than 99.9% for both polarities. For all pairs of polarity evaluated during the saturation test, the polarity effect was lower than the recommended limit. The maximum variation obtained for angular dependence test was only 0.5%. The chamber tested in this work achieved the expected results in the case of all pre-operational tests realized: stability, leakage current, angular dependence, saturation, ion collection and polarity effect. Evaluating the satisfactory results obtained, it is possible to indicate the usefulness of this ionization chamber for dosimetry in {sup 60}Co gamma radiation beams. (author)

  14. Cellular Pathways in Response to Ionizing Radiation and Their Targetability for Tumor Radiosensitization.

    Science.gov (United States)

    Maier, Patrick; Hartmann, Linda; Wenz, Frederik; Herskind, Carsten

    2016-01-14

    During the last few decades, improvements in the planning and application of radiotherapy in combination with surgery and chemotherapy resulted in increased survival rates of tumor patients. However, the success of radiotherapy is impaired by two reasons: firstly, the radioresistance of tumor cells and, secondly, the radiation-induced damage of normal tissue cells located in the field of ionizing radiation. These limitations demand the development of drugs for either radiosensitization of tumor cells or radioprotection of normal tissue cells. In order to identify potential targets, a detailed understanding of the cellular pathways involved in radiation response is an absolute requirement. This review describes the most important pathways of radioresponse and several key target proteins for radiosensitization.

  15. Cellular Pathways in Response to Ionizing Radiation and Their Targetability for Tumor Radiosensitization

    Directory of Open Access Journals (Sweden)

    Patrick Maier

    2016-01-01

    Full Text Available During the last few decades, improvements in the planning and application of radiotherapy in combination with surgery and chemotherapy resulted in increased survival rates of tumor patients. However, the success of radiotherapy is impaired by two reasons: firstly, the radioresistance of tumor cells and, secondly, the radiation-induced damage of normal tissue cells located in the field of ionizing radiation. These limitations demand the development of drugs for either radiosensitization of tumor cells or radioprotection of normal tissue cells. In order to identify potential targets, a detailed understanding of the cellular pathways involved in radiation response is an absolute requirement. This review describes the most important pathways of radioresponse and several key target proteins for radiosensitization.

  16. Systems Engineering and Safety Issues in Scientific Facilities Subject to Ionizing Radiations

    Directory of Open Access Journals (Sweden)

    Pierre Bonnal

    2013-10-01

    Full Text Available The conception and development of large- scale scientific facilities emitting ionizing radiations rely more on project management practices in use in the process industry than on systems engineering practices. This paper aims to highlight possible reasons for this present situation and to propose some ways to enhance systems engineering so that the specific radiation safety requirements are considered and integrated in the approach. To do so, we have reviewed lessons learned from the management of large-scale scientific projects and more specifically that of the Large Hadron Collider project at CERN. It is shown that project management and systems engineering practices are complementary and can beneficially be assembled in an integrated and lean managerial framework that grants the appropriate amount of focus to safety and radiation safety aspects.

  17. SEM analysis of ionizing radiation effects in an analog to digital converter /AD571/

    Science.gov (United States)

    Gauthier, M. K.; Perret, J.; Evans, K. C.

    1981-01-01

    The considered investigation is concerned with the study of the total-dose degradation mechanisms in an IIL analog to digital (A/D) converter. The A/D converter is a 10 digit device having nine separate functional units on the chip which encompass several hundred transistors and circuit elements. It was the objective of the described research to find the radiation sensitive elements by a systematic search of the devices on the LSI chip. The employed technique using a scanning electron microscope to determine the functional blocks of an integrated circuit which are sensitive to ionizing radiation and then progressively zeroing in on the soft components within those blocks, proved extremely successful on the AD571. Four functional blocks were found to be sensitive to radiation, including the Voltage Reference, DAC, IIL Clock, and IIL SAR.

  18. Epidemiologic Study of One Million American Workers and Military Veterans Exposed to Ionizing Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Boice, John D. [International Epidemiology Inst. Ltd., Rockville, MD (United States)

    2015-02-27

    A pilot study was completed demonstrating the feasibility of conducting an epidemiologic study assessing cancer and other disease mortality among nearly one million US veterans and workers exposed to ionizing radiation, a population 10 times larger than atomic bomb survivor study with high statistical power to evaluate low dose rate effects. Among the groups enumerated and/or studied were: (1) 194,000 Department of Energy Uranium Workers; (2) 6,700 Rocketdyne Radiation Workers; (3) 7,000 Mound Radiation Workers; (4) 156,000 DOE Plutonium Workers; (5) 212,000 Nuclear Power Plant Workers; (6) 130,000 Industrial Radiography Workers; (7) 1.7 million Medical Workers and (8) 135,000 Atomic Veterans.

  19. Effect of ionized plasma medium on the radiation from a RITMA structure on ferrite substrate

    Indian Academy of Sciences (India)

    V Bhardwaj; V K Tiwari; D Bhatnagar; J S Saini; K B Sharma

    2003-12-01

    This paper presents theoretical investigations on the radiation properties of a right isosceles triangular microstrip antenna (RITMA) printed on a magnetized ferrite substrate Ni0.62Co0.02Fe1.948O4 in the presence of ionized plasma medium. The theoretical study on RITMA structure in free space is carried out in TM11 mode of excitation by applying cavity model-based modal expansion technique while hydrodynamic theory is used for its analysis in plasma medium. By varying the bias magnetic field, far-field radiation patterns in free space and plasma medium are obtained which in turn are applied in computing radiated power, directivity, quality factor and bandwidth of antenna. It is found that the presence of plasma medium affects the performance of RITMA structure significantly.

  20. Combined action of ionizing radiation with another factor: common rules and theoretical approach

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Kyu; Roh, Changhyun, E-mail: jkkim@kaeri.re.kr [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Komarova, Ludmila N.; Petin, Vladislav G., E-mail: vgpetin@yahoo.com [Medical Radiological Research Center, Obninsk (Russian Federation)

    2013-07-01

    Two or more factors can simultaneously make their combined effects on the biological objects. This study has focused on theoretical approach to synergistic interaction due to the combined action of radiation and another factor on cell inactivation. A mathematical model for the synergistic interaction of different environmental agents was suggested for quantitative prediction of irreversibly damaged cells after combined exposures. The model takes into account the synergistic interaction of agents and based on the supposition that additional effective damages responsible for the synergy are irreversible and originated from an interaction of ineffective sub lesions. The experimental results regarding the irreversible component of radiation damage of diploid yeast cells simultaneous exposed to heat with ionizing radiation or UV light are presented. A good agreement of experimental results with model predictions was demonstrated. The importance of the results obtained for the interpretation of the mechanism of synergistic interaction of various environmental factors is discussed. (author)

  1. [Radiation situation prognosis for deep space: reactions of water and living systems to chronic low-dose ionizing irradiation].

    Science.gov (United States)

    Ushakov, I B; Tsetlin, V V; Moisa, S S

    2013-01-01

    The authors review the findings of researches into the effects of low-dose ionizing irradiation on diverse biological objects (embryonic Japanese quails, Aspergillus niger, Spirostomum ambiguum Ehrbg., mesenchymal stem cells from mouse marrow, dry higher plants seeds, blood lymphocytes from pilots and cosmonauts). Model experiments with chronic exposure to ionizing radiation doses comparable with the measurements inside orbital vehicles and estimations for trips through the interplanetary space resulted in morphological disorders (embryonic Japanese quails, Aspergillus niger), radiation hormesis (Aspergillus niger, MSCs from mouse marrow), increase in the seed germination rate, inhibition of Spirostomum spontaneous activity, DNA damages, chromosomal aberrations, and increase of the blood lymphocytes reactivity to additional radiation loading. These facts give grounds to assume that the crucial factor in the radiation outcomes is changes in liquid medium. In other words, during extended orbiting within the magnetosphere region and interplanetary missions ionizing radiation affects primarily liquids of organism and, secondarily, its morphofunctional structures.

  2. Ionizing radiation exposures in treatments of solid neoplasms are not associated with subsequent increased risks of chronic lymphocytic leukemia.

    Science.gov (United States)

    Radivoyevitch, Tomas; Sachs, Rainer K; Gale, Robert Peter; Smith, Mitchell R; Hill, Brian T

    2016-04-01

    Exposure to ionizing radiation is not thought to cause chronic lymphocytic leukemia (CLL). Challenging this notion are recent data suggesting CLL incidence may be increased by radiation exposure from the atomic bombs (after many decades), uranium mining and nuclear power facility accidents. To assess the effects of therapeutic ionizing radiation for the treatment of solid neoplasms we studied CLL risks in data from the Surveillance, Epidemiology, and End Results (SEER) Program. Specifically, we compared the risks of developing CLL in persons with a 1(st) non-hematologic cancer treated with or without ionizing radiation. We controlled for early detection effects on CLL risk induced by surveillance after 1(st) cancer diagnoses by forming all-time cumulative CLL relative risks (RR). We estimate such CLL RR to be 1.20 (95% confidence interval, 1.17, 1.23) for persons whose 1(st) cancer was not treated with ionizing radiation and 1.00 (0.96, 1.05) for persons whose 1(st) cancer was treated with ionizing radiations. These results imply that diagnosis of a solid neoplasm is associated with an increased risk of developing CLL only in persons whose 1(st) cancer was not treated with radiation therapy.

  3. Comparative study of the use of non-ionizing and ionizing radiation in the cure of epoxy resin: microwave versus electron electron

    Energy Technology Data Exchange (ETDEWEB)

    Kersting, Daniel, E-mail: daniel.kersting@usp.br [Centro Tecnologico da Marinha em Sao Paulo (CTMSP/USP), Sao Paulo, SP (Brazil); Wiebeck, Helio, E-mail: hwiebeck@usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Escola Politecnica. Dept. de Engenharia Metalurgica; Marinucci, Gerson; Silva, Leonardo G.A. e, E-mail: marinuci@ipen.br, E-mail: gasilva@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    Several processes for curing epoxy resins were developed over the years. Two methods are discussed in this paper, in order to present the main advantages and disadvantages of using microwave radiation (non-ionizing radiation) and electron beam radiation (ionizing radiation). The microwave radiation is a non-ionizing radiation, with great power of penetration and transfer of heat in microwave absorbing materials, or materials with microwave absorbing fillers. The frequency usually used in research and development is 2.45 GHz, the same available in commercial equipment. The microwave effect provides increase on the collision velocity between the reactant which, combined with energy absorbed by the reaction system, accelerates the curing reaction. None modifications in the epoxy system are required to use microwave heating for the curing process.On the other hand, the electron beam is a form of ionizing radiation in which the high energy electrons have the ability to interact with the irradiated material and produce ions, free radicals, and molecules in excited state, which can be used to initiate and propagate a polymerization. Specific initiators are necessary for an effective cure of the resin. In this study, a DGEBA epoxy resin with initiators based on anhydride and amine was used under the same conditions indicated by the manufacturer. The curing of the catalyzed system was performed in a domestic microwave oven adapted for laboratory use. The degradation and glass transition temperatures were evaluated by thermal analysis techniques. For comparative purposes, it was used data available in the literature for electron beam irradiation. (author)

  4. Compact Raman Lidar Measurement of Liquid and Vapor Phase Water Under the Influence of Ionizing Radiation

    Directory of Open Access Journals (Sweden)

    Shiina Tatsuo

    2016-01-01

    Full Text Available A compact Raman lidar has been developed for studying phase changes of water in the atmosphere under the influence of ionization radiation. The Raman lidar is operated at the wavelength of 349 nm and backscattered Raman signals of liquid and vapor phase water are detected at 396 and 400 nm, respectively. Alpha particles emitted from 241Am of 9 MBq ionize air molecules in a scattering chamber, and the resulting ions lead to the formation of liquid water droplets. From the analysis of Raman signal intensities, it has been found that the increase in the liquid water Raman channel is approximately 3 times as much as the decrease in the vapor phase water Raman channel, which is consistent with the theoretical prediction based on the Raman cross-sections. In addition, the radius of the water droplet is estimated to be 0.2 μm.

  5. On the influence of low-energy ionizing radiation on the amino acid molecule: proline

    Science.gov (United States)

    Tamuliene, Jelena; Romanova, Liudmila; Vukstich, Vasyl; Papp, Alexander; Shkurin, Serhiy; Baliulyte, Laura; Snegursky, Alexander

    2016-06-01

    New data on the electron-impact fragmentation of the amino acid proline molecule are presented as being related to the formation of the ionized products due to the influence of low-energy ionizing radiation on the above molecule. An extensive DFT-theory based on the theoretical approach enabled the main pathways of the proline molecules fragmentation to be elucidated. A series of the produced fragments have been identified. The absolute appearance energies for some of them have been both measured experimentally and calculated theoretically. The data of the experimental studies and theoretical calculations are compared and analyzed. 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.

  6. Mechanistic study of the toxicity of ionizing radiation in Daphnia magna

    Energy Technology Data Exchange (ETDEWEB)

    Parisot, F.; Alonzo, F. [Institut de Radioprotection et de Surete Nucleaire, IRSN/PRP-ENV/SERIS/LECO, Laboratoire d' Ecotoxicologie des Radionucleides, Cadarache (France); Bourdineaud, J.P. [UMR CNRS 5805 EPOC - OASU Station Marine d' Arcachon Universite Bordeaux 1, Arcachon (France); Poggiale, J.C. [Mediterranean Institute of Oceanography - MIO - UMR 7294 Pytheas Institute - OSU, Aix-Marseille University, Marseille (France)

    2014-07-01

    In the last decade, the ecological impact of ionizing radiation has emerged as a growing scientific concern for ecosystems protection. However, the assessment of potential radiological effects on the environment is hampered by both a gap of available scientific data and a lack in proven methods. Understanding how ionizing radiation affects wildlife at biologically and ecologically relevant scales is a major issue in environmental protection. This issue is one of the objectives of the Strategic Research Agenda (SRA) developed in the framework of the European program STAR (Strategy for Allied Radioecology). In this context, the present PhD project aims to evaluate chronic effects of external Cs-137 gamma radiation at low doses on a representative species of aquatic ecosystems, the cladoceran crustacean Daphnia magna. More precisely, the objectives of this study are to evaluate multi-generational effects of irradiation on: (i) genotoxic effects and their potential consequences on survival, somatic growth and fecundity, (ii) the energy budget and (iii) the population dynamics of Daphnia. An experimental design was developed to expose daphnids to low doses of ionizing radiation ranging from 0,008 to 32 mGy.h{sup -1} across 3 successive generations (75 days). DNA damages were assessed using random amplified polymorphic DNA and real time PCR (RAPD - PCR). Effects on survival, somatic growth and fecundity were monitored for 21-25 days in each generation, from hatching to release of brood 5. Our aim is to: examine a potential correlation between molecular (DNA) damage and effects observed at the individual level (survival, somatic growth and fecundity) across generations and test the suitability of DNA damage as an early indice of future trans-generational effects. As a future perspective, individual and molecular effects data will be analysed using a DEBtox model (Dynamic Energy Budget Applied to Toxicology) in order to identify the metabolic modes of action of ionizing

  7. Effects of ionizing radiation on bone cell differentiation in an experimental murine bone cell model

    Science.gov (United States)

    Baumstark-Khan, Christa; Lau, Patrick; Hellweg, Christine; Reitz, Guenther

    During long-term space travel astronauts are exposed to a complex mixture of different radiation types under conditions of dramatically reduced weight-bearing activity. It has been validated that astronauts loose a considerable amount of bone mass at a rate up to one to two percent each month in space. Therapeutic doses of ionizing radiation cause bone damage and increase fracture risks after treatment for head-and-neck cancer and in pelvic irradiation. For low radiation doses, the possibility of a disturbed healing potential of bone was described. Radiation induced damage has been discussed to inflict mainly on immature and healing bone. Little is known about radiation effects on bone remodelling and even less on the combined action of microgravity and radiation. Bone remodelling is a life-long process performed by balanced action of cells from the osteoblast and osteoclast lineages. While osteoblasts differentiate either into bone-lining cells or into osteocytes and play a crucial role in bone matrix synthesis, osteoclasts are responsible for bone resorption. We hypothesize that the balance between bone matrix assembly by osteocytes and bone degradation by osteoclasts is modulated by microgravity as well as by ionizing radiation. To address this, a cell model consisting of murine cell lines with the potential to differentiate into bone-forming osteoblasts (OCT-1, MC3T3-E1 S24, and MC3T3-E1 S4) was used for studying radiation response after exposure to simulated components of cosmic radiation. Cells were exposed to graded doses of 150 kV X-rays, α particles (0.525 MeV/u, 160 keV/µm; PTB, Braunschweig, Germany) and accelerated heavy ions (75 MeV/u carbon, 29 keV/µm; 95 MeV/u argon, 230 keV/µm; GANIL, Caen, France). Cell survival was measured as colony forming ability; cell cycle progression was analyzed via fluorescence-activated cell scanning (FACS) by measurement of the content of propidium iodide-stained DNA, DNA damage was visualized by γH2AX

  8. Astrophysical Conditions for Planetary Habitability

    CERN Document Server

    Guedel, M; Erkaev, N; Kasting, J; Khodachenko, M; Lammer, H; Pilat-Lohinger, E; Rauer, H; Ribas, I; Wood, B E

    2014-01-01

    With the discovery of hundreds of exoplanets and a potentially huge number of Earth-like planets waiting to be discovered, the conditions for their habitability have become a focal point in exoplanetary research. The classical picture of habitable zones primarily relies on the stellar flux allowing liquid water to exist on the surface of an Earth-like planet with a suitable atmosphere. However, numerous further stellar and planetary properties constrain habitability. Apart from "geophysical" processes depending on the internal structure and composition of a planet, a complex array of astrophysical factors additionally determine habitability. Among these, variable stellar UV, EUV, and X-ray radiation, stellar and interplanetary magnetic fields, ionized winds, and energetic particles control the constitution of upper planetary atmospheres and their physical and chemical evolution. Short- and long-term stellar variability necessitates full time-dependent studies to understand planetary habitability at any point ...

  9. Developmental effects of magnetic field (50 Hz) in combination with ionizing radiation and chemical teratogens.

    Science.gov (United States)

    Pafková, H; Jerábek, J; Tejnorová, I; Bednár, V

    1996-11-01

    The influence of a 50 Hz magnetic field (MF) on avian and mammalian embryogenesis, the MF level and vector, as well as the effect of exposure to MF (50 Hz, 10 mT) in combination with X-rays has been recently reported [2,3]. No significant alterations of chick or rat embryogenesis were found after repeated exposures to 50 Hz MF at 10 mT or 6 microT or with different vectors. However, X-ray chick embryotoxicity was significantly affected by repeated exposures of developing organisms to MF. A strong dependence of effect on the type of interaction was revealed. A decrease of X-ray induced teratogenicity was observed when MF preceded X-ray exposure (indirect interaction), while MF exposure applied immediately after X-ray radiation (direct interaction) non-significantly potentiated adverse developmental effects of ionizing radiation. This study deals with the effects of MF in combination with insulin or tetracycline. Exposure of chick embryos to MF influenced the sensitivity of embryonic morphogenetic systems to the subsequently administered chemical teratogens, insulin and/or tetracycline. A protective effect of MF was detected similarly as in the case of indirect interaction with ionizing radiation.

  10. Scientific foundation of regulating ionizing radiation: application of metrics for evaluation of regulatory science information.

    Science.gov (United States)

    Moghissi, A Alan; Gerraa, Vikrham Kumar; McBride, Dennis K; Swetnam, Michael

    2014-11-01

    This paper starts by describing the historical evolution of assessment of biologic effects of ionizing radiation leading to the linear non-threshold (LNT) system currently used to regulate exposure to ionizing radiation. The paper describes briefly the concept of Best Available Science (BAS) and Metrics for Evaluation of Scientific Claims (MESC) derived for BAS. It identifies three phases of regulatory science consisting of the initial phase, when the regulators had to develop regulations without having the needed scientific information; the exploratory phase, when relevant tools were developed; and the standard operating phase, when the tools were applied to regulations. Subsequently, an attempt is made to apply the BAS/MESC system to various stages of LNT. This paper then compares the exposure limits imposed by regulatory agencies and also compares them with naturally occurring radiation at several cities. Controversies about LNT are addressed, including judgments of the U.S. National Academies and their French counterpart. The paper concludes that, based on the BAS/MESC system, there is no disagreement between the two academies on the scientific foundation of LNT; instead, the disagreement is based on their judgment or speculation.

  11. In vivo optical imaging of tumor and microvascular response to ionizing radiation.

    Directory of Open Access Journals (Sweden)

    Azusa Maeda

    Full Text Available Radiotherapy is a widely used cancer treatment. However, understanding how ionizing radiation affects tumor cells and their vasculature, particularly at cellular, subcellular, genetic, and protein levels, has been limited by an inability to visualize the response of these interdependent components within solid tumors over time and in vivo. Here we describe a new preclinical experimental platform combining intravital multimodal optical microscopy for cellular-level longitudinal imaging, a small animal x-ray microirradiator for reproducible spatially-localized millimeter-scale irradiations, and laser-capture microdissection of ex vivo tissues for transcriptomic profiling. Using this platform, we have developed new methods that exploit the power of optically-enabled microscopic imaging techniques to reveal the important role of the tumor microvasculature in radiation response of tumors. Furthermore, we demonstrate the potential of this preclinical platform to study quantitatively--with cellular and sub-cellular details--the spatio-temporal dynamics of the biological response of solid tumors to ionizing radiation in vivo.

  12. In vivo optical imaging of tumor and microvascular response to ionizing radiation.

    Science.gov (United States)

    Maeda, Azusa; Leung, Michael K K; Conroy, Leigh; Chen, Yonghong; Bu, Jiachuan; Lindsay, Patricia E; Mintzberg, Shani; Virtanen, Carl; Tsao, Julissa; Winegarden, Neil A; Wang, Yanchun; Morikawa, Lily; Vitkin, I Alex; Jaffray, David A; Hill, Richard P; DaCosta, Ralph S

    2012-01-01

    Radiotherapy is a widely used cancer treatment. However, understanding how ionizing radiation affects tumor cells and their vasculature, particularly at cellular, subcellular, genetic, and protein levels, has been limited by an inability to visualize the response of these interdependent components within solid tumors over time and in vivo. Here we describe a new preclinical experimental platform combining intravital multimodal optical microscopy for cellular-level longitudinal imaging, a small animal x-ray microirradiator for reproducible spatially-localized millimeter-scale irradiations, and laser-capture microdissection of ex vivo tissues for transcriptomic profiling. Using this platform, we have developed new methods that exploit the power of optically-enabled microscopic imaging techniques to reveal the important role of the tumor microvasculature in radiation response of tumors. Furthermore, we demonstrate the potential of this preclinical platform to study quantitatively--with cellular and sub-cellular details--the spatio-temporal dynamics of the biological response of solid tumors to ionizing radiation in vivo.

  13. Hematological Changes Induced by Mercury Ions and Ionizing Radiation in Experimental Animals

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin-Kyu; Lee, Yun-Jong; Choi, Dae-Seong [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Kim, Ji-Hyang [Biotechnology Research Institute, Seoul (Korea, Republic of); Cebulska-Wasilewska, Antonina [The Henryk Niewodniczanski Institute of Nuclear Physics, Krakow (Poland)

    2006-07-01

    Toxic metals such as lead, chromium, cadmium, mercury and arsenic are widely found in our environment. Humans are exposed to these metals from numerous sources, including contaminated air, water, soil and food. Mercury, one of the most diffused and hazardous organ specific environmental contaminants, exists in a wide variety of physical and chemical states, each of which has unique characteristics for a target organ specificity. Although reports indicate that mercury induces deleterious damage, little is known about its effects on living organisms. Ionizing radiation, an extensively used therapeutic modality in oncology, not only eradicates neoplastic cells but also generates inevitable side effects for normal tissues. Such biological effects are made through the production of reactive oxygen species which include a superoxide anion, a hydroxyl radical and a hydrogen peroxide. These reactive species may contribute to the radiation-induced cytotoxicity (e.g., chromosome aberrations, protein oxidation, and muscle injury) and to the metabolic and morphologic changes (e.g., increased muscle proteolysis and changes in the central nervous system) in animals and humans. In the present study, radioimmunoassay of the cortisol in the serum and the analysis of the hematological components and enzymes related to a tissue injury were carried out to evaluate the effects of mercury chloride in comparison with those of ionizing radiation.

  14. The structure of radiative shock waves. III. The model grid for partially ionized hydrogen gas

    CERN Document Server

    Fadeyev, Y A; Fadeyev, Yu. A.

    2001-01-01

    The grid of the models of radiative shock waves propagating through partially ionized hydrogen gas with temperature 3000K <= T_1 <= 8000K and density 10^{-12} gm/cm^3 <= \\rho_1 <= 10^{-9}gm/cm^3 is computed for shock velocities 20 km/s <= U_1 <= 90 km/s. The fraction of the total energy of the shock wave irreversibly lost due to radiation flux ranges from 0.3 to 0.8 for 20 km/s <= U_1 <= 70 km/s. The postshock gas is compressed mostly due to radiative cooling in the hydrogen recombination zone and final compression ratios are within 1 <\\rho_N/\\rho_1 \\lesssim 10^2, depending mostly on the shock velocity U_1. The preshock gas temperature affects the shock wave structure due to the equilibrium ionization of the unperturbed hydrogen gas, since the rates of postshock relaxation processes are very sensitive to the number density of hydrogen ions ahead the discontinuous jump. Both the increase of the preshock gas temperature and the decrease of the preshock gas density lead to lower postsh...

  15. Low-power laser irradiation did not stimulate breast cancer cells following ionizing radiation

    Science.gov (United States)

    Silva, C. R.; Camargo, C. F. M.; Cabral, F. V.; Ribeiro, M. S.

    2016-03-01

    Cancer has become a public health problem worldwide. Radiotherapy may be a treatment to a number of types of cancer, frequently using gamma-radiation with sources such as 137Cs and 60Co, with varying doses, dose rates, and exposure times to obtain a better as a stimulant for cell proliferation and tissue healing process. However, its effects on cancer cells are not yet well elucidated. The purpose of this work was to evaluate the effects of the LPL on breast cancer cultures after ionizing radiation. The breast cancer-MDA-MB-231 cells were gamma irradiated by a 60Co source, with dose of 2.5 Gy. After 24h, cells were submitted to LPL irradiation using a red laser emitting at λ= 660 nm, with output power of 40 mW and exposure time of 30 s and 60 s. The plates were uniformly irradiated, with energy of 1.2 J and 2.4 J, respectively. Cell viability was analyzed using the exclusion method with trypan blue. Our results show that breast cancer cells submitted to LPL after ionizing radiation remained 95 % viable. No statistically significant differences were observed between laser and control untreated cells, (P > 0.05). These findings suggest that LPL did not influenced cancer cells viability.

  16. Ecological effects of various toxic agents on the aquatic microcosm in comparison with acute ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Fuma, S. E-mail: fuma@nirs.go.jp; Ishii, N.; Takeda, H.; Miyamoto, K.; Yanagisawa, K.; Ichimasa, Y.; Saito, M.; Kawabata, Z.; Polikarpov, G.G

    2003-07-01

    The purpose of this study was an evaluation of the effect levels of various toxic agents compared with acute doses of ionizing radiation for the experimental model ecosystem, i.e., microcosm mimicking aquatic microbial communities. For this purpose, the authors used the microcosm consisting of populations of the flagellate alga Euglena gracilis as a producer, the ciliate protozoan Tetrahymena thermophila as a consumer and the bacterium Escherichia coli as a decomposer. Effects of aluminum and copper on the microcosm were investigated in this study, while effects of {gamma}-rays, ultraviolet radiation, acidification, manganese, nickel and gadolinium were reported in previous studies. The microcosm could detect not only the direct effects of these agents but also the community-level effects due to the interspecies interactions or the interactions between organisms and toxic agents. The authors evaluated doses or concentrations of each toxic agent which had the following effects on the microcosm: (1) no effects; (2) recognizable effects, i.e., decrease or increase in the cell densities of at least one species; (3) severe effects, i.e., extinction of one or two species; and (4) destructive effects, i.e., extinction of all species. The resulting effects data will contribute to an ecological risk assessment of the toxic agents compared with acute doses of ionizing radiation.

  17. Theory-Agnostic Constraints on Black-Hole Dipole Radiation with Multiband Gravitational-Wave Astrophysics.

    Science.gov (United States)

    Barausse, Enrico; Yunes, Nicolás; Chamberlain, Katie

    2016-06-17

    The aLIGO detection of the black-hole binary GW150914 opens a new era for probing extreme gravity. Many gravity theories predict the emission of dipole gravitational radiation by binaries. This is excluded to high accuracy in binary pulsars, but entire classes of theories predict this effect predominantly (or only) in binaries involving black holes. Joint observations of GW150914-like systems by aLIGO and eLISA will improve bounds on dipole emission from black-hole binaries by 6 orders of magnitude relative to current constraints, provided that eLISA is not dramatically descoped.

  18. MAGNETIC FIELDS AND THE POLARIZATION OF ASTROPHYSICAL MASER RADIATION: A REVIEW

    Directory of Open Access Journals (Sweden)

    W. D. Watson

    2009-01-01

    Full Text Available Basic aspects of the relationship between the magnetic eld and polarized maser radiation are described with the emphasis on interpreting the observed spectra. Special attention is given to three issues { the limitations on the applicability of the classic solutions of Goldreich, Keeley, & Kwan (1973, inferring the strength of the magnetic eld from the circular polarization when the Zeeman splitting is much less than the spectral linebreadth (especially for SiO masers, and the signi cance of the absence of components of the Zeeman triplet in the spectra of OH masers in regions of star formation.

  19. Effects of ionizing radiation on proteins in lyophilized or frozen demineralized human bone

    Science.gov (United States)

    Antebi, Uri; Mathor, Monica Beatriz; da Silva, André Ferreira; Guimarães, Rodrigo Pereira; Honda, Emerson Kiyoshi

    2016-01-01

    Objective The aim was to study the effects of application of ionizing radiation (gamma and electrons) as sterilizing agents at doses of 15 kGy, 25 kGy and 50 kGy, on lyophilized or frozen demineralized bone tissue for use in transplants. Methods Five human femoral diaphyses from different donors of musculoskeletal tissue were demineralized and preserved as lyophilized or frozen at −80 °C. The samples were divided into two groups: non-irradiated (control) and irradiated by means of gamma rays or an electron beam. The bone proteins were extracted and used to determine the concentrations of total protein and BMP 2 and 7. Results Decreases in total protein and BMP 2 and 7 concentrations were observed. The decreases in total protein concentrations, in comparison with the respective control groups, were significant in the lyophilized and frozen samples that were irradiated at a dose of 50 kGy of gamma radiation and electron beam, with reductions of more than 30%. Significant decreases in the levels of BMP 2 and 7 were also observed at higher doses and especially through use of the electron beam. Conclusion The reductions in the concentrations of total proteins and osteoinductive proteins (BMP 2 and 7) were related to the radiation dose, i.e. they increased with higher doses of ionizing radiation type and the type of bone preservation. The largest reductions in concentrations were observed in the bones irradiated by means of an electron beam and at a dose of 50 kGy. However, this type of radiation and this high dose are not usual practices for sterilization of bone tissue. PMID:27069893

  20. Exposure to electromagnetic fields (non-ionizing radiation) and its relationship with childhood leukemia: A systematic review

    Energy Technology Data Exchange (ETDEWEB)

    Calvente, I.; Fernandez, M.F. [Laboratory of Medical Investigations, San Cecilio University Hospital, CIBER de Epidemiologia y Salud Publica (CIBERESP) (Spain); Department of Radiology, University of Granada, Granada (Spain); Villalba, J. [Department of Radiology, University of Granada, Granada (Spain); Olea, N. [Laboratory of Medical Investigations, San Cecilio University Hospital, CIBER de Epidemiologia y Salud Publica (CIBERESP) (Spain); Department of Radiology, University of Granada, Granada (Spain); Nunez, M.I., E-mail: isabeln@ugr.es [Department of Radiology, University of Granada, Granada (Spain)

    2010-07-15

    Childhood exposure to physical contamination, including non-ionizing radiation, has been implicated in numerous diseases, raising concerns about the widespread and increasing sources of exposure to this type of radiation. The primary objective of this review was to analyze the current state of knowledge on the association between environmental exposure to non-ionizing radiation and the risk of childhood leukemia. Scientific publications between 1979 and 2008 that include examination of this association have been reviewed using the MEDLINE/PubMed database. Studies to date have not convincingly confirmed or ruled out an association between non-ionizing radiation and the risk of childhood leukemia. Discrepancies among the conclusions of the studies may also be influenced by confounding factors, selection bias, and misclassification. Childhood defects can result from genetic or epigenetic damage and from effects on the embryo or fetus, which may both be related to environmental exposure of the parent before conception or during the pregnancy. It is therefore critical for researchers to define a priori the type and 'window' of exposure to be assessed. Methodological problems to be solved include the proper diagnostic classification of individuals and the estimated exposure to non-ionizing radiation, which may act through various mechanisms of action. There appears to be an urgent need to reconsider exposure limits for low frequency and static magnetic fields, based on combined experimental and epidemiological research into the relationship between exposure to non-ionizing radiation and adverse human health effects.

  1. Exposure to electromagnetic fields (non-ionizing radiation) and its relationship with childhood leukemia: a systematic review.

    Science.gov (United States)

    Calvente, I; Fernandez, M F; Villalba, J; Olea, N; Nuñez, M I

    2010-07-15

    Childhood exposure to physical contamination, including non-ionizing radiation, has been implicated in numerous diseases, raising concerns about the widespread and increasing sources of exposure to this type of radiation. The primary objective of this review was to analyze the current state of knowledge on the association between environmental exposure to non-ionizing radiation and the risk of childhood leukemia. Scientific publications between 1979 and 2008 that include examination of this association have been reviewed using the MEDLINE/PubMed database. Studies to date have not convincingly confirmed or ruled out an association between non-ionizing radiation and the risk of childhood leukemia. Discrepancies among the conclusions of the studies may also be influenced by confounding factors, selection bias, and misclassification. Childhood defects can result from genetic or epigenetic damage and from effects on the embryo or fetus, which may both be related to environmental exposure of the parent before conception or during the pregnancy. It is therefore critical for researchers to define a priori the type and "window" of exposure to be assessed. Methodological problems to be solved include the proper diagnostic classification of individuals and the estimated exposure to non-ionizing radiation, which may act through various mechanisms of action. There appears to be an urgent need to reconsider exposure limits for low frequency and static magnetic fields, based on combined experimental and epidemiological research into the relationship between exposure to non-ionizing radiation and adverse human health effects.

  2. Resonantly Enhanced Multiphoton Ionization under XUV FEL radiation: A case study of the role of harmonics

    CERN Document Server

    Nikolopoulos, Georgios M

    2016-01-01

    We provide a detailed quantitative study of the possible role of a small admixture of harmonics on resonant two-photon ionization. The motivation comes from the occasional presence of 2nd and 3rd harmonics in FEL radiation. We obtain the dependence of ionic yields on the intensity of the fundamental, the percentage of 2nd harmonic and the detuning of the fundamental from resonance. Having examined the cases of one and two intermediate resonances, we arrive at results of general validity and global behavior, showing that even a small amount of harmonic may seem deceptively innocuous.

  3. Cytogenetic and hormonal studies of persons occupationally irradiated with ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, B.; Maleeva, A.; Praskova, L.; Mileva, M.; Bulanova, M.

    1979-01-01

    Cytogenetic and hormonal investigations were carried out on 23 subjects working in the sphere of ionizing radiation at medical institutions. Statistically significant differences in number of chromosomal aberrations were found between medical personnel and the general public, and in the group of personnel with more than 10 years of service. Futhermore, among the medical personnel, a statistically significant decrease was found in the level of sex hormones in blood plasma. Plasma cortisol levels were increased in all subjects examined whereas aldosterone levels were normal in subjcts with a length of service to 10 years and were lower in those with a length of service over 10 years.

  4. Air filled ionization chambers and their response to high LET radiation

    DEFF Research Database (Denmark)

    Kaiser, Franz-Joachim; Bassler, Niels; Tölli, Heikki

    Background Air filled ionization chambers (ICs) are widely used for absolute dosimetry, not only in photon beams but also in beams of heavy charged particles. Within the IC, electron hole pairs are generated by the energy deposition originating from incoming radiation. High-LET particles create...... structure theory. More specifically, we solved the equation for the geometrical setup of the Bragg-peak IC, which is a plane parallel IC with a 2 mm spacing between the electrodes. The sensitive volume of the IC is located in a thermoplastic housing of several mm thickness. Results We compare...

  5. Medical uses non-ionizing radiation; Uso medicos de radiaciones no ionizantes

    Energy Technology Data Exchange (ETDEWEB)

    Ubeda Maeso, A.; Trillo Ruiz, M. A.

    2016-08-01

    This article reviews various clinical applications of non-ionizing radiation, focusing on the Hz-GHz frequency range. Depending on the signal characteristics, the applications cover several therapeutic areas, including osteology and traumatology, tissue regeneration, physiotherapy, chronic pain treatment, neurology, cardiology, urology and oncology. Electromagnetic therapies have proved simple, safe, low cost, devoid of side effects and able to treat the underlying pathology rather than simply alleviate the symptoms. Therefore, it is predictable that these therapies will have as serious impact on public health and associated costs. (Author)

  6. Energetic ionized helium in the quiet time radiation belts - Theory and comparison with observation

    Science.gov (United States)

    Spjeldvik, W. N.; Fritz, T. A.

    1978-01-01

    Theoretical calculations of helium ion distributions in the inner magnetosphere are compared to observations made by ATS-6 and Explorer-45. Coupled transport equations for equatorially mirroring singly and doubly ionized helium ions in the steady state limit with an outer boundary of L = 7 are solved. Radial profiles and energy spectra are computed at all lower L values. Theoretical quiet time predictions are compared to satellite observations of energetic helium ions in the lower MeV range. It is found that the theory adequately represents the principal characteristics of the radiation belt helium ion population.

  7. Inter-Individual Variability in Human Response to Low-Dose Ionizing Radiation, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Rocke, David [Univ. of California, Davis, CA (United States)

    2016-08-01

    In order to investigate inter-individual variability in response to low-dose ionizing radiation, we are working with three models, 1) in-vivo irradiated human skin, for which we have a realistic model, but with few subjects, all from a previous project, 2) ex-vivo irradiated human skin, for which we also have a realistic model, though with the limitations involved in keeping skin pieces alive in media, and 3) MatTek EpiDermFT skin plugs, which provides a more realistic model than cell lines, which is more controllable than human samples.

  8. Ionospheric Absorption on 1539 Khz in Relation to Solar Ionizing Radiation

    Science.gov (United States)

    Boska, J.

    1984-01-01

    Radio wave absorption data on 1539 kHz for the summer period of 1978 to 1980 are considered in relation to variations of solar X-ray and L-alpha radiation. It is shown that under non-flare conditions L-alpha dominates in controlling absorption and that X-rays contribute about 10% to the total absorption. Optimum regression equations show that absorption is proportional to the m-th power of ionizing flux where m 1. The role of correcting L-alpha values, measured by the AE-E satellite, is discussed.

  9. Effects of ionizing-radiation and post-radiation action of some plant growth regulators on the seed germination and seedling growth of Scotch pine

    Directory of Open Access Journals (Sweden)

    Leszek Michalski

    2015-01-01

    Full Text Available The effects of small doses of gamma irradiation on the seed germination and seedling growth of Scotch pine and post-radiation action of water solutions of IAA, GA3 and kinetin have been investigated. Changes in the destructive action of ionizing-radiation toy gibberellic acid and its intensifying by IAA and kinetin has been found.

  10. Ionizing radiation selectively reduces skin regulatory T cells and alters immune function.

    Directory of Open Access Journals (Sweden)

    Yu Zhou

    Full Text Available The skin serves multiple functions that are critical for life. The protection from pathogens is achieved by a complicated interaction between aggressive effectors and controlling functions that limit damage. Inhomogeneous radiation with limited penetration is used in certain types of therapeutics and is experienced with exposure to solar particle events outside the protection of the Earth's magnetic field. This study explores the effect of ionizing radiation on skin immune function. We demonstrate that radiation, both homogeneous and inhomogeneous, induces inflammation with resultant specific loss of regulatory T cells from the skin. This results in a hyper-responsive state with increased delayed type hypersensitivity in vivo and CD4+ T cell proliferation in vitro. The effects of inhomogeneous radiation to the skin of astronauts or as part of a therapeutic approach could result in an unexpected enhancement in skin immune function. The effects of this need to be considered in the design of radiation therapy protocols and in the development of countermeasures for extended space travel.

  11. Ionizing Radiation Selectively Reduces Skin Regulatory T Cells and Alters Immune Function

    Science.gov (United States)

    Zhou, Yu; Ni, Houping; Balint, Klara; Sanzari, Jenine K.; Dentchev, Tzvete; Diffenderfer, Eric S.; Wilson, Jolaine M.; Cengel, Keith A.; Weissman, Drew

    2014-01-01

    The skin serves multiple functions that are critical for life. The protection from pathogens is achieved by a complicated interaction between aggressive effectors and controlling functions that limit damage. Inhomogeneous radiation with limited penetration is used in certain types of therapeutics and is experienced with exposure to solar particle events outside the protection of the Earth’s magnetic field. This study explores the effect of ionizing radiation on skin immune function. We demonstrate that radiation, both homogeneous and inhomogeneous, induces inflammation with resultant specific loss of regulatory T cells from the skin. This results in a hyper-responsive state with increased delayed type hypersensitivity in vivo and CD4+ T cell proliferation in vitro. The effects of inhomogeneous radiation to the skin of astronauts or as part of a therapeutic approach could result in an unexpected enhancement in skin immune function. The effects of this need to be considered in the design of radiation therapy protocols and in the development of countermeasures for extended space travel. PMID:24959865

  12. Comparison of the ionizing radiation effects on cochineal, annatto and turmeric natural dyes

    Science.gov (United States)

    Cosentino, Helio M.; Takinami, Patricia Y. I.; del Mastro, Nelida L.

    2016-07-01

    As studies on radiation stability of food dyes are scarce, commercially important natural food grade dyes were evaluated in terms of their sensitivity against gamma ionizing radiation. Cochineal, annatto and turmeric dyes with suitable concentrations were subjected to increasing doses up to 32 kGy and analyzed by spectrophotometry and capillary electrophoresis. The results showed different pattern of absorbance versus absorbed dose for the three systems. Carmine, the glucosidal coloring matter from the scale insect Coccus cacti L., Homoptera (cochineal) remained almost unaffected by radiation up to doses of about 32 kGy (absorbance at 494 nm). Meanwhile, at that dose, a plant-derived product annatto or urucum (Bixa orellana L.) tincture presented a nearly 58% reduction in color intensity. Tincture of curcumin (diferuloylmethane) the active ingredient in the eastern spice turmeric (Curcuma longa) showed to be highly sensitive to radiation when diluted. These data shall be taken in account whenever food products containing these food colors were going to undergo radiation processing.

  13. Cancer risk at low doses of ionizing radiation: artificial neural networks inference from atomic bomb survivors.

    Science.gov (United States)

    Sasaki, Masao S; Tachibana, Akira; Takeda, Shunichi

    2014-05-01

    Cancer risk at low doses of ionizing radiation remains poorly defined because of ambiguity in the quantitative link to doses below 0.2 Sv in atomic bomb survivors in Hiroshima and Nagasaki arising from limitations in the statistical power and information available on overall radiation dose. To deal with these difficulties, a novel nonparametric statistics based on the 'integrate-and-fire' algorithm of artificial neural networks was developed and tested in cancer databases established by the Radiation Effects Research Foundation. The analysis revealed unique features at low doses that could not be accounted for by nominal exposure dose, including (i) the presence of a threshold that varied with organ, gender and age at exposure, and (ii) a small but significant bumping increase in cancer risk at low doses in Nagasaki that probably reflects internal exposure to (239)Pu. The threshold was distinct from the canonical definition of zero effect in that it was manifested as negative excess relative risk, or suppression of background cancer rates. Such a unique tissue response at low doses of radiation exposure has been implicated in the context of the molecular basis of radiation-environment interplay in favor of recently emerging experimental evidence on DNA double-strand break repair pathway choice and its epigenetic memory by histone marking.

  14. A Therapeutic Role for Survivin in Mitigating the Harmful Effects of Ionizing Radiation

    Directory of Open Access Journals (Sweden)

    Katherine H. Carruthers

    2016-01-01

    Full Text Available Background. Radiation therapy is a form of adjuvant care used in many oncological treatment protocols. However, nonmalignant neighboring tissues are harmed as a result of this treatment. Therefore, the goal of this study was to induce the production of survivin, an antiapoptotic protein, to determine if this protein could provide protection to noncancerous cells during radiation exposure. Methods. Using a murine model, a recombinant adenoassociated virus (rAAV was used to deliver survivin to the treatment group and yellow fluorescence protein (YFP to the control group. Both groups received targeted radiation. Visual inspection, gait analysis, and tissue histology were used to determine the extent of damage caused by the radiation. Results. The YFP group demonstrated ulceration of the irradiated area while the survivin treated mice exhibited only hair loss. Histology showed that the YFP treated mice experienced dermal thickening, as well as an increase in collagen that was not present in the survivin treated mice. Gait analysis demonstrated a difference between the two groups, with the YFP mice averaging a lower speed. Conclusions. The use of gene-modification to induce survivin expression in normal tissues allows for the protection of nontarget areas from the negative side effects normally associated with ionizing radiation.

  15. Modeling of transient ionizing radiation effects in bipolar devices at high dose-rates

    Energy Technology Data Exchange (ETDEWEB)

    FJELDLY,T.A.; DENG,Y.; SHUR,M.S.; HJALMARSON,HAROLD P.; MUYSHONDT,ARNOLDO

    2000-04-25

    To optimally design circuits for operation at high intensities of ionizing radiation, and to accurately predict their a behavior under radiation, precise device models are needed that include both stationary and dynamic effects of such radiation. Depending on the type and intensity of the ionizing radiation, different degradation mechanisms, such as photoelectric effect, total dose effect, or single even upset might be dominant. In this paper, the authors consider the photoelectric effect associated with the generation of electron-hole pairs in the semiconductor. The effects of low radiation intensity on p-II diodes and bipolar junction transistors (BJTs) were described by low-injection theory in the classical paper by Wirth and Rogers. However, in BJTs compatible with modem integrated circuit technology, high-resistivity regions are often used to enhance device performance, either as a substrate or as an epitaxial layer such as the low-doped n-type collector region of the device. Using low-injection theory, the transient response of epitaxial BJTs was discussed by Florian et al., who mainly concentrated on the effects of the Hi-Lo (high doping - low doping) epilayer/substrate junction of the collector, and on geometrical effects of realistic devices. For devices with highly resistive regions, the assumption of low-level injection is often inappropriate, even at moderate radiation intensities, and a more complete theory for high-injection levels was needed. In the dynamic photocurrent model by Enlow and Alexander. p-n junctions exposed to high-intensity radiation were considered. In their work, the variation of the minority carrier lifetime with excess carrier density, and the effects of the ohmic electric field in the quasi-neutral (q-n) regions were included in a simplified manner. Later, Wunsch and Axness presented a more comprehensive model for the transient radiation response of p-n and p-i-n diode geometries. A stationary model for high-level injection in p

  16. High spatial resolution dosimetric response maps for radiotherapy ionization chambers measured using kilovoltage synchrotron radiation

    Science.gov (United States)

    Butler, D. J.; Stevenson, A. W.; Wright, T. E.; Harty, P. D.; Lehmann, J.; Livingstone, J.; Crosbie, J. C.

    2015-11-01

    Small circular beams of synchrotron radiation (0.1 mm and 0.4 mm in diameter) were used to irradiate ionization chambers of the types commonly used in radiotherapy. By scanning the chamber through the beam and measuring the ionization current, a spatial map of the dosimetric response of the chamber was recorded. The technique is able to distinguish contributions to the large-field ionization current from the chamber walls, central electrode and chamber stem. Scans were recorded for the NE 2571 Farmer chamber, the PTW 30013, IBA FC65-G Farmer-type chambers, the NE 2611A and IBA CC13 thimble chambers, the PTW 31006 and 31014 pinpoint chambers, the PTW Roos and Advanced Markus plane-parallel chambers, and the PTW 23342 thin-window soft x-ray chamber. In all cases, large contributions to the response arise from areas where the incident beam grazes the cavity surfaces. Quantitative as well as qualitative information about the relative chamber response was extracted from the maps, including the relative contribution of the central electrode. Line scans using monochromatic beams show the effect of the photon energy on the chamber response. For Farmer-type chambers, a simple Monte Carlo model was in good agreement with the measured response.

  17. Flow cytometry protocol to evaluate ionizing radiation effects on P-glycoprotein activity

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Neyliane Goncalves dos; Amaral, Ademir; Cavalcanti, Mariana Brayner [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear]. E-mail; neylisantos@yahoo.com.br; Neves, Maria Amelia Batista; Machado, Cintia Gonsalves de Faria [Fundacao de Hematologia e Hemoterapia de Pernambuco, Recife, PE (Brazil). Unidade de Laboratorios Especializados. Lab. de Imunofenotipagem

    2008-12-15

    The aim of this work was to establish a protocol to evaluate ionizing radiation effects on P-glycoprotein (P-gp) activity. For this, human peripheral blood samples were irradiated in vitro with different doses and P-gp activity was analyzed for CD4 and CD8 T lymphocytes through rhodamine123-efflux assay by flow cytometry. By simultaneous employment of percentage and mean fluorescence index parameters, subject-by-subject analysis pointed out changes in P-gp activity for some individuals and irradiated samples. Based on this work, the proposed protocol was considered adequate for evaluating P-gp activity on cells after radioactive stress. Besides, this research suggests that P-gp activity could be an important factor to define patient-specific protocols in combined chemo- and radiotherapy, particularly when radiation exposure precedes chemical treatment. (author)

  18. Effect of ionizing radiation on the thermal oxidative stability of medical polymers

    Energy Technology Data Exchange (ETDEWEB)

    Woo, L.; Ling, M.T.K.; Ding, S.Y.; Westphal, S.P. [Baxter International, Round Lake, IL 60073 (United States)

    1998-12-21

    In the medical-device industry, most products need to be sterilized prior to use. Sterilization by ionizing radiation is fast becoming the preferred method on account of its effectiveness and economy. However, energetic secondary electrons released from the primary irradiation event can cause significant damage and degrade the polymer. We have undertaken a study on the thermal oxidative stability of several medical polymers as measured by the oxidative induction time (OIT) on radiation exposures. It was found that, in selected cases with polyolefins, active antioxidants can be completely consumed during the sterilization process, leaving the polymer unprotected for the required shelf life. In addition, comparison between {gamma}- and electron-beam irradiation sources revealed major differences on OIT reduction, primarily due to the dose rate effect. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  19. Strong Correlation among Three Biodosimetry Techniques Following Exposures to Ionizing Radiation

    Science.gov (United States)

    Kang, Chang-Mo; Yun, Hyun Jin; Kim, Hanna; Kim, Cha Soon

    2016-01-01

    Three in vitro dose calibration curves for biodosimetry such as dicentric chromosome assay, fluorescence in situ hybridization (FISH) assay for translocation, and micronuclei (MNs) in binucleated cell assay were established after exposure to ionizing radiation. Peripheral blood lymphocyte samples obtained from healthy donors were irradiated with 60Co source at a dose rate of 0.5 Gy/min to doses of 0.1–6 Gy. The results from three in vitro dose calibration curves for biodosimetry were analyzed to understand the relationship among biodosimetry assay techniques. Our comparison demonstrates that there is a very strong positive correlation among the dicentric assay, FISH, and MNs analysis, and these three biodosimetry assays strongly support the in vitro dose reconstruction and the emergency preparedness of public or occupational radiation overexposure. PMID:28217287

  20. ММР and RHOA gene expression in persoms exposed to ionizing radiation

    Directory of Open Access Journals (Sweden)

    Mikhailov V.F.

    2013-12-01

    Full Text Available The purpose of the study is to investigate the mechanisms of MMP-7, -13, TIMP-2 and RhoA genes expression in blood cells after ionizing radiation exposure. Material and methods.\\Ne had examined blood samples from 27 healthy donors, 32 prostate cancer patients before and after radiotherapy, and 32 Chernobyl liquidators by qRT-PCR method. Result. Our results suggests that the expression of MMP-7, MMP-13 genes in prostate cancer patients with grade 2 (T2N0M0. Probably, these changes were associated with the tumor process development, but no with radiation therapy. RhoA level in blood of liquidators was decreased.

  1. Radiation effects in Caenorhabditis elegans - Mutagenesis by high and low LET ionizing radiation

    Science.gov (United States)

    Nelson, Gregory A.; Schubert, Wayne W.; Marshall, Tamara M.; Benton, Eric R.; Benton, Eugene V.

    1989-01-01

    The nematode C. elegans was used to measure the effectiveness of high-energy ionized particles in the induction of three types of genetic lesions. Recessive lethal mutations in a 40-map unit autosomal region, sterility, and X-chromosome nondisjunction or damage were investigated. Induction rates were measured as a function of linear energy transfer, LET(infinity), for nine ions of atomic nunmber 1-57 accelerated at the BEVALAC accelerator. Linear kinetics were observed for all three types of lesions within the dose/fluence ranges tested and were found to vary strongly as a function of particle LET(infinity). Relative biological effectiveness (RBE) values of up to 4.2 were measured, and action cross sections were calculated and compared to mutagenic responses in other systems.

  2. Effect of ionizing radiation on transcription of colorectal cancer MDR1 gene of HCT-8 cells

    Institute of Scientific and Technical Information of China (English)

    Xiao-Feng Li; Lin Ma; Jing Lu; Li-Xia Kong; Xiao-Hua Long; Su-Huan Liao; Bao-Rong Chi

    2013-01-01

    Objective: To discuss effect of ionizing radiation on transcription of colorectal cancer multidrug resistance (MDR) 1 gene of HCT-8 cells. Methods: Total RNA was extracted by guanidine thiocyanate one-step method. Northern blot was applied to detect transcription level of MDR1 gene. The expression of P-gp protein was detected by flow cytometry. Results: The expression of MDR1 of normal colorectal cancer HCT-8 cells was low. It was increased by 8.35 times under stimulus with 2 Gy. When treated with low doses in advance, high expressed MDR was decreased significantly under 0.05, 0.1 Gy, which was 69.00%, 62.89% in 2 Gy group and 5.77 times, 5.25 times in sham irradiation group. No obvious difference was detected between (0.2+2) Gy group and 2 Gy group. Compared with sham irradiation group, the percentage of P-gp positive cells after radiation of a high 2 Gy dose was increased significantly (P<0.01). When treated with high radiation dose following low radiation dose (0.05 Gy, 0.1 Gy) in advance, the percentage of P-gp positive cells were also increased significantly. The percentage of P-gp positive cells were increased obviously in 0.2 Gy and 2 Gy groups. Compared with simple high radiation 2 Gy group, the percentage of P-gp positive cells was decreased significantly (P<0.05). Conclusions:Low radiation dose can reverse multidrug resistance of colorectal cancer cells caused by high radiation dose.

  3. Combined effects of streptozotocin-diabetes and ionizing radiation on nephropathy in the rat

    Energy Technology Data Exchange (ETDEWEB)

    Claycamp, H.G.

    1982-01-01

    The individual effects of radiation and diabetes on nephropathy in the rat are well-documented; however, the combined effects of these factors on nephropathy have not been adequately studied. The combined effect of radiation and diabetes on nephropathy is a significant problem in view of human populations at risk; diabetic radiation workers and diabetic radiotherapy patients. Streptozotocin-diabetic and control rats were irradiated using 137-Cs to whole body doses of 0, 0.29, 1.0, 3.0, and 5.0 Gy. Glomerulopathy in the rats was measured using standard histological grading techniques on left kidney biopsy samples taken at times of one month prior to and three, six and nine months after irradiation. Twelve months after irradiation, both right and left kidneys were graded for the degree of glomerulopathy. A pilot tubular attributes study of the histologic samples was added in which eight attributes of tubular histopathology were scored for the degree of severity. The acute effects of radiation on hemopoiesis were studied in the 0, 0.29, 1.0, 3.0, and 5.0 Gy rats, and dose levels of 7.0 and 8.5 Gy were added to extend the dose range of the hemopoiesis study only. The factors of diabetes, irradiation, time after irradiation and the interactions of these factors did not significantly affect glomerulopathy in the rats. Radiation also was not a significant factor in the tubular attribute study. The results of this study imply that diabetic radiation workers are not at a significantly increased risk of nephropathy as a result of ionizing radiation exposure.

  4. Radiation hormesis. Stimulatory effects of low level ionizing radiation on plant

    Energy Technology Data Exchange (ETDEWEB)

    Kinoshita, Shigenobu; Masui, Hisashi; Yoshida, Shigeo; Murata, Isao [Osaka Univ., Suita (Japan). Faculty of Engineering

    1999-04-01

    Recently, the study for radiation hormesis has been executed against animals and plants; subharmful doses of radiation may evoke a stimulatory response in any organism. We executed irradiating experiments of dry seeds with fusion (D-T) neutron, fission neutron, cobalt-60 gamma-ray and investigated existence of the radiation hormesis effects by measuring germination, the length of a stalk and the total weight of a seed leaf on the 7th day after starting cultivation. And we estimated radiation hormesis effects by relative effectiveness, the ratio of the mean value of measurement subjects for the irradiated group to that of non-irradiated group. In relation to Raphanus sativus, the hormesis effects on seed leaf growth from irradiated seeds have only turned up in seed groups irradiated by the fusion (D-T) neutron. We have confirmed that absorbed dose range which revealed the effects is from 1 cGy to 10 Gy and the increasing rate is from 5 percent to 25 percent against a control group. (author)

  5. Molecular Characterization of TP53 Gene in Human Populations Exposed to Low-Dose Ionizing Radiation

    Directory of Open Access Journals (Sweden)

    Igor Brasil-Costa

    2013-01-01

    Full Text Available Ionizing radiation, such as that emitted by uranium, may cause mutations and consequently lead to neoplasia in human cells. The TP53 gene acts to maintain genomic integrity and constitutes an important biomarker of susceptibility. The present study investigated the main alterations observed in exons 4, 5, 6, 7, and 8 of the TP53 gene and adjacent introns in Amazonian populations exposed to radioactivity. Samples were collected from 163 individuals. Occurrence of the following alterations was observed: (i a missense exchange in exon 4 (Arg72Pro; (ii 2 synonymous exchanges, 1 in exon 5 (His179His, and another in exon 6 (Arg213Arg; (iii 4 intronic exchanges, 3 in intron 7 (C → T at position 13.436; C → T at position 13.491; T → G at position 13.511 and 1 in intron 8 (T → G at position 13.958. Alteration of codon 72 was found to be an important risk factor for cancer development (P=0.024; OR=6.48; CI: 1.29–32.64 when adjusted for age and smoking. Thus, TP53 gene may be an important biomarker for carcinogenesis susceptibility in human populations exposed to ionizing radiation.

  6. HgI2 nanostructures obtained hydrothermally for application in ionizing radiation detection

    Science.gov (United States)

    Pérez Barthaburu, María; Galain, Isabel; Aguiar, Ivana; Bentos Pereira, Heinkel; Fornaro, Laura

    2016-11-01

    The compound semiconductor HgI2 has been widely studied and employed as a material for ionizing radiation detection. Monocrystal growth is an intricate method for obtaining materials for this application. With the aim of finding a simpler and more effective way to develop ionizing radiation detectors, we employed HgI2 nanostructures subjected to a hydrothermal treatment and then pressed for this purpose. In the synthesis procedure, aqueous solutions of Hg(NO3)2 and NaI were mixed until their reaction completed and the suspension obtained was then placed in a homemade autoclave and heated at 120 °C for 2, 10 or 24 h. We confirmed the HgI2 tetragonal phase by powder XRD in all cases, independently of the synthesis conditions employed. Nanoparticles were characterized by their size and morphology by TEM. We used the HgI2 nanostructures to obtain a pellet by applying 0.7 GPa of pressure at room temperature. The pellet was then used to construct the detector, and we studied the electrical properties of the detector and its response to 241Am sources of different exposure rates. The resistivity and signal-to-noise ratio obtained are of the order of those reported for HgI2 detectors assembled with monocrystals. The results obtained in this work encourage us to work further on this topic, improving the method, scaling the detector’s size and studying its spectrometric grade.

  7. Assessment of Genotoxicity of Ionizing radiation using Tradescantia-Comet assay

    Energy Technology Data Exchange (ETDEWEB)

    Han, Min; Ryu, Tae Ho; Hyun, Kyung Man; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Wilhelmova, Nad [Institute of Experimental Botany, Prague (Czech Republic)

    2010-05-15

    Over the last two decades, several new methodologies for the detection of DNA damage have been developed. The comet assay is currently used in different areas of biological sciences to detect DNA damage. The comet assay, also called the single cell gel electrophoresis (SCGE) was first introduced by Ostling and Johanson as a microelectrophoretic technique for the direct visualization of DNA damage in individual cells. 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. Although the genotoxic effects detected by Tradescantia tests cannot be associated with mutagenesis or even carcinogenesis in humans, these bioassays 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

  8. Gene expression in response to ionizing radiation and family history of gastric cancer.

    Science.gov (United States)

    Marcon, Francesca; Silvestrini, Francesco; Siniscalchi, Ester; Palli, Domenico; Saieva, Calogero; Crebelli, Riccardo

    2011-03-01

    Genes and molecular pathways involved in familial clustering of gastric cancer have not yet been identified. The purpose of the present study was to investigate gene expression changes in response to a cellular stress, and its link with a positive family history for this neoplasia. To this aim leukocytes of healthy first-degree relatives of gastric cancer patients and controls were challenged in vitro with ionizing radiation and gene expression evaluated 4 h later on microarrays with 1,800 cancer-related genes. Eight genes, mainly involved in signal transduction and cell cycle regulation, were differentially expressed in healthy relatives of gastric cancer cases. Functional class scoring by Gene Ontology classification highlighted two G-protein related pathways, implicated in the proliferation of neoplastic tissue, which were differentially expressed in healthy subjects with positive family history of gastric cancer. The relative expression of 84 genes related to these pathways was examined using the SYBR green-based quantitative real-time PCR. The results confirmed the indication of an involvement of G-protein coupled receptor pathways in GC familiarity provided by microarray analysis. This study indicates a possible association between familiarity for gastric cancer and altered transcriptional response to ionizing radiation.

  9. Human epidermal keratinocytes death and expression of protein markers of apoptosis after ionizing radiation exposure

    Directory of Open Access Journals (Sweden)

    Sharon Wong

    2013-12-01

    and p21 was observed in skin that had received 50Gy of irradiation. The maximum expression of p53 (range 37.09% to 50.91% was reached at 10Gy.Conclusion: Findings from this study will assist clinicians in predicting radiation induced skin toxicity with the current changes in radiation fractionation protocols.-----------------------------------Cite this article as: Wong S, Chor HH, Moothy S, Ong CT, Phan TT, Lu JJ. Human epidermal keratinocytes death and expression of protein markers of apoptosis after ionizing radiation exposure. Int J Cancer Ther Oncol 2013; 1(2:01027.DOI: http://dx.doi.org/10.14319/ijcto.0102.7

  10. Creating a strategy for science-based national policy: Addressing conflicting views on the health risk of low-level ionizing radiation. Final report, Wingspread Conference

    Energy Technology Data Exchange (ETDEWEB)

    McClellan, Roger O.; Apple, Martin A.

    1998-03-03

    Significant cancer risk for adults exposed to more than 100 millisieverts (10 REM) of ionizing radiation. More research on low-level ionizing radiation is needed in molecular and cellular mechanisms of injury and ongoing exposed populations. Implementation costs should be considered in regulating low-level ionizing radiation. Comparative risk assessment is a powerful tool for risk-based policy formation, and conflicting legal statutes should become harmonized for radiation regulation. More public dialog on low-level radiation is needed. A high level commission should evaluate radiation hazard control practices.

  11. 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)

  12. Non-ionizing radiation hazards - dealing with misconceptions, uncertainties, and risk communication

    Energy Technology Data Exchange (ETDEWEB)

    Sliney, D. [USA Center for Health Promotion and Preventive Medicine, Gunpowder, MD (United States)

    2004-07-01

    Non-ionizing radiation hazards are not always easily defined, at the hazards frequently are very much dependent upon frequency and wavelength and exposure geometry matters. This leads to rather technical exposure limits that are not the easiest to communicate to the worker or the general public. The problem is most difficult to explain for spectral (frequency bands) outside of the visible, when there is little or no perception. Both workers and the general public also do not enjoy uncertainty about a risk. Thus, with new technologies employing laser and RF radiation, all of the biological information may be not be completed, but greater safety factors were introduced into exposure guidelines to account for the magnitude of the uncertainties. Fortunately for the optical radiation safety community, the level of unwarranted concerns about health and safety at exposures below recommended exposure limits have generally been less than those working with radiofrequency radiation and low-frequency electro-magnetic fields. When the apparent experts appear to disagree, as when the interpretation of individual biological research studies are widely publicized, the level of discomfort upon an exposed population increases. Still more frustrating for the public health officials is the use of health and safety questions by special interest groups or commercial interests to delay the use of a particular technology. Myths of hazards from low-power lasers, or cell phones provide us with a challenge for better training of workers and better risk communication with the public. (orig.)

  13. Long-term correlation of the electrocorticogram as a bioindicator of brain exposure to ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, L.A.A.; Nogueira, R.A. [Universidade Federal Rural de Pernambuco (UFRPE), Recife, PE (Brazil). Departamento de Morfologia e Fisiologia Animal. Lab. de Biofisica Teorico-Experimental e Computacional; Silva, I.M.S.; Fernandes, T.S., E-mail: ran.pe@terra.com.br [Universidade Federal Rural de Pernambuco (UFRPE), Recife, PE (Brazil). Departamento de Biofisica e Radiobiologia

    2015-10-15

    Understanding the effects of radiation and its possible influence on the nervous system are of great clinical interest. However, there have been few electrophysiological studies on brain activity after exposure to ionizing radiation (IR). A new methodological approach regarding the assessment of the possible effects of IR on brain activity is the use of linear and nonlinear mathematical methods in the analysis of complex time series, such as brain oscillations measured using the electrocorticogram (ECoG). The objective of this study was to use linear and nonlinear mathematical methods as biomarkers of gamma radiation regarding cortical electrical activity. Adult Wistar rats were divided into 3 groups: 1 control and 2 irradiated groups, evaluated at 24 h (IR24) and 90 days (IR90) after exposure to 18 Gy of gamma radiation from a cobalt-60 radiotherapy source. The ECoG was analyzed using power spectrum methods for the calculation of the power of delta, theta, alpha and beta rhythms and by means of the a-exponent of the detrended fluctuation analysis (DFA). Using both mathematical methods it was possible to identify changes in the ECoG, and to identify significant changes in the pattern of the recording at 24 h after irradiation. Some of these changes were persistent at 90 days after exposure to IR. In particular, the theta wave using the two methods showed higher sensitivity than other waves, suggesting that it is a possible biomarker of exposure to IR. (author)

  14. Long-term correlation of the electrocorticogram as a bioindicator of brain exposure to ionizing radiation

    Directory of Open Access Journals (Sweden)

    L.A.A. Aguiar

    2015-01-01

    Full Text Available Understanding the effects of radiation and its possible influence on the nervous system are of great clinical interest. However, there have been few electrophysiological studies on brain activity after exposure to ionizing radiation (IR. A new methodological approach regarding the assessment of the possible effects of IR on brain activity is the use of linear and nonlinear mathematical methods in the analysis of complex time series, such as brain oscillations measured using the electrocorticogram (ECoG. The objective of this study was to use linear and nonlinear mathematical methods as biomarkers of gamma radiation regarding cortical electrical activity. Adult Wistar rats were divided into 3 groups: 1 control and 2 irradiated groups, evaluated at 24 h (IR24 and 90 days (IR90 after exposure to 18 Gy of gamma radiation from a cobalt-60 radiotherapy source. The ECoG was analyzed using power spectrum methods for the calculation of the power of delta, theta, alpha and beta rhythms and by means of the α-exponent of the detrended fluctuation analysis (DFA. Using both mathematical methods it was possible to identify changes in the ECoG, and to identify significant changes in the pattern of the recording at 24 h after irradiation. Some of these changes were persistent at 90 days after exposure to IR. In particular, the theta wave using the two methods showed higher sensitivity than other waves, suggesting that it is a possible biomarker of exposure to IR.

  15. Ionizing radiation fluctuations and large-scale structure in the Lyman-alpha forest

    CERN Document Server

    Croft, R A C

    2003-01-01

    We investigate the large-scale inhomogeneities of the hydrogen ionizing radiation field in the Universe at redshift z=3. Using a raytracing algorithm, we simulate a model in which quasars are the dominant sources of radiation. We make use of large scale N-body simulations of a LambdaCDM universe, and include such effects as finite quasar lifetimes and output on the lightcone, which affects the shape of quasar light echoes. We create Lya forest spectra that would be generated in the presence of such a fluctuating radiation field, finding that the power spectrum of the Lya forest can be suppressed by as much as 15 % for modes with k=0.05-1 Mpc/h. This relatively small effect may have consequences for high precision measurements of the Lya power spectrum on larger scales than have yet been published. We also investigate another radiation field probe, the cross-correlation of quasar positions and the Lya forest. For both quasar lifetimes which we simulate (10^7 yr and 10^8 yr), we expect to see a strong decrease ...

  16. Sterilization by ionizing radiation comparative evaluation; Sterilizzazione mediante radiazioni e confronto con le tecniche convenzionali

    Energy Technology Data Exchange (ETDEWEB)

    Tata, A. [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dip. Innovazione; Giuliani, S.

    1996-01-01

    Sterilization of surgical and medical devices by ionizing radiation (gamma or accelerated electron beams) is currently regarded as one of the main industrial-scale applications of radiation technology processes. Considering the most widely utilized chemical-physical methods (i.e. ethylene oxide (EtO) fumigation and radiation treatment), about 10-12 millions m(3) of surgical and medical devices are estimated to be processed yearly all around the world, of which 70 % by EtO, 27% by gamma-irradiation and 3% using accelerated beams. Due to the increasing demand for reusable and single-use devices, and the need of assuring their sterility in order to prevent, as much as possible, the diffusion of serious infective diseases (among which for instance Aids), the market of sterilization of these items is considerably expanding. In the general depicted scenario, radiation technologies are expected to gain a leading role, even a part from their economic attractiveness, as an alternative to EtO treatment, which is more and more considered as responsible for increasing environmental, social and public health problems.

  17. Development and characterization of acrylated palm oil nanoparticles using ionizing radiation

    Science.gov (United States)

    Tajau, Rida; Yunus, Wan Md Zin Wan; Dahlan, Khairul Zaman Mohd; Mahmood, Mohd Hilmi; Hashim, Kamaruddin

    2012-11-01

    In this study, the utilization of radiation crosslinking methods which are known as intermolecular and intramolecular crosslinking for the formation of nanoparticles of Acrylated Palm Oil (APO) in the microemulsion system that also consists of Pluronic F-127 (PF-127) surfactant was demonstrated. This microemulsion system was subjected to the ionizing radiation i.e. gamma irradiation at different doses to form the crosslinked APO nanoparticles. The effects of radiation doses on the size of APO nanoparticles were investigated using the Dynamic Light Scattering (DLS) method and their images were viewed using the Transmission Electron Microcrospy (TEM). The Fourier Transform Infra-Red (FTIR) spectroscopy was used to characterize the chemical structure and the crosslinking conversion of carbon-carbon double bond (-C = C-) of the APO nanoparticles after irradiation. As a result, the size of the APO nanoparticle decreased when the irradiation dose increased. Reduce in size might be due to the effect of intramolecular crosslinking reaction of the APO nanoparticles during irradiation process. Meanwhile, the intramolecular -C = C- crosslinking conversion percentage was increased at doses below 1kGy before decreasing at the higher dose that might due to the intermolecular crosslinking of the macromolecules. This study showed that radiation crosslinking methods of polymerization and crosslinking in the microemulsion were found to be promising for the synthesis of nanoparticles.

  18. Chromosomal Aberrations in Human Peripheral Blood Lymphocytes after Exposure to Ionizing Radiation

    Science.gov (United States)

    Ryu, Tae Ho; Kim, Jin-Hong; Kim, Jin Kyu

    2016-01-01

    Biological dosimetry using chromosome aberration analyses in human peripheral blood lymphocytes is suitable and useful tool for estimating the dose when a nuclear or radiological emergency is investigated. Blood samples from five healthy donors were obtained to establish dose-response calibration curves for chromosomal aberrations after exposure to ionizing radiation. In this work, dicentric assay and CBMN assay were compared considering the sensitivity and accuracy of dose estimation. In a total of 21,688 analyzed metaphase spreads, 10,969 dicentric chromosomes, 563 centric rings and 11,364 acentric chromosomes were found. The number of metaphase cells decreased with increasing radiation dose. The centric rings were not found in the non-irradiated control. There was no relationship between radiation dose and acentric ring induction. The frequency of total MN increased in a dose-dependent manner. In comparison with the control value, MN increased about 9, 32, 75, 87, and 52 fold higher after treatment with 1, 2, 3, 4, and 5 Gy, respectively. The results revealed that the mean frequency of chromosomal aberrations, both in dicentric and in micronuclei analyses increased with increasing radiation dose. PMID:28217281

  19. Development and characterization of acrylated palm oil nanoparticles using ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Tajau, Rida; Yunus, Wan Md Zin Wan; Dahlan, Khairul Zaman Mohd; Mahmood, Mohd Hilmi; Hashim, Kamaruddin [Malaysian Nuclear Agency (Nuclear Malaysia), Radiation Processing Technology Division (BTS), Bangi, 43000 Kajang, Selangor (Malaysia); Chemistry Department, Faculty of Science, University Putra Malaysia (UPM), 43400 UPM Serdang, Selangor (Malaysia); Malaysian Nuclear Agency (Nuclear Malaysia), Radiation Processing Technology Division (BTS), Bangi, 43000 Kajang, Selangor (Malaysia)

    2012-11-27

    In this study, the utilization of radiation crosslinking methods which are known as intermolecular and intramolecular crosslinking for the formation of nanoparticles of Acrylated Palm Oil (APO) in the microemulsion system that also consists of Pluronic F-127 (PF-127) surfactant was demonstrated. This microemulsion system was subjected to the ionizing radiation i.e. gamma irradiation at different doses to form the crosslinked APO nanoparticles. The effects of radiation doses on the size of APO nanoparticles were investigated using the Dynamic Light Scattering (DLS) method and their images were viewed using the Transmission Electron Microcrospy (TEM). The Fourier Transform Infra-Red (FTIR) spectroscopy was used to characterize the chemical structure and the crosslinking conversion of carbon-carbon double bond (-C = C-) of the APO nanoparticles after irradiation. As a result, the size of the APO nanoparticle decreased when the irradiation dose increased. Reduce in size might be due to the effect of intramolecular crosslinking reaction of the APO nanoparticles during irradiation process. Meanwhile, the intramolecular -C C- crosslinking conversion percentage was increased at doses below 1kGy before decreasing at the higher dose that might due to the intermolecular crosslinking of the macromolecules. This study showed that radiation crosslinking methods of polymerization and crosslinking in the microemulsion were found to be promising for the synthesis of nanoparticles.

  20. Detection of the Level of Reactive Oxygen Species Induced by Ionizing Radiation in Cells

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Kyu; Chung, Dong Min; Kim, Jin-Hong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    By definition, the direct effect is referred to interaction between photon and DNA molecule, whereas the indirect effect is mediated by the reactive oxygen species (ROS) generated by radiolysis and subsequent reaction. It has been reported that ROS produced after exposure to IR can react with cellular materials such as DNA, proteins, carbohydrates and lipids. ROS is free radicals such as the superoxide anion, hydroxyl radicals and the non-radical hydrogen peroxide. Cells generate ROS during aerobic metabolism. Excessive production of ROS can lead to oxidative stress, genetic alteration and even cell death. It has been reported that ROS plays a critical role in radiation-induced cell injury. Thus, it is of great interest to determine the radiation-induced ROS level. Many kinds of methods to detect the level of ROS have been developed so far. There were random changes of fluorescence intensity in the treatment after irradiation. This result meant that this protocol was not appropriate for determination of radiation-induced ROS. On the other hand, the fluorescence intensity was increased in a dose-dependent manner when the cells were treated with the DCFH-DA solution before irradiation. Conclusions can be drawn from the experimental results of this study. In order to properly measure the ROS level in the cells exposed to ionizing radiation, the cells should be treated with the DCFH-DA solution before irradiation.

  1. Phosphoproteomics Profiling of Human Skin Fibroblast Cells Reveals Pathways and Proteins Affected by Low Doses of Ionizing Radiation

    Science.gov (United States)

    Yang, Feng; Waters, Katrina M.; Miller, John H.; Gritsenko, Marina A.; Zhao, Rui; Du, Xiuxia; Livesay, Eric A.; Purvine, Samuel O.; Monroe, Matthew E.; Wang, Yingchun; Camp, David G.; Smith, Richard D.; Stenoien, David L.

    2010-01-01

    Background High doses of ionizing radiation result in biological damage; however, the precise relationships between long-term health effects, including cancer, and low-dose exposures remain poorly understood and are currently extrapolated using high-dose exposure data. Identifying the signaling pathways and individual proteins affected at the post-translational level by radiation should shed valuable insight into the molecular mechanisms that regulate dose-dependent responses to radiation. Principal Findings We have identified 7117 unique phosphopeptides (2566 phosphoproteins) from control and irradiated (2 and 50 cGy) primary human skin fibroblasts 1 h post-exposure. Semi-quantitative label-free analyses were performed to identify phosphopeptides that are apparently altered by radiation exposure. This screen identified phosphorylation sites on proteins with known roles in radiation responses including TP53BP1 as well as previously unidentified radiation-responsive proteins such as the candidate tumor suppressor SASH1. Bioinformatic analyses suggest that low and high doses of radiation affect both overlapping and unique biological processes and suggest a role for MAP kinase and protein kinase A (PKA) signaling in the radiation response as well as differential regulation of p53 networks at low and high doses of radiation. Conclusions Our results represent the most comprehensive analysis of the phosphoproteomes of human primary fibroblasts exposed to multiple doses of ionizing radiation published to date and provide a basis for the systems-level identification of biological processes, molecular pathways and individual proteins regulated in a dose dependent manner by ionizing radiation. Further study of these modified proteins and affected networks should help to define the molecular mechanisms that regulate biological responses to radiation at different radiation doses and elucidate the impact of low-dose radiation exposure on human health. PMID:21152398

  2. Phosphoproteomics profiling of human skin fibroblast cells reveals pathways and proteins affected by low doses of ionizing radiation.

    Directory of Open Access Journals (Sweden)

    Feng Yang

    Full Text Available BACKGROUND: High doses of ionizing radiation result in biological damage; however, the precise relationships between long-term health effects, including cancer, and low-dose exposures remain poorly understood and are currently extrapolated using high-dose exposure data. Identifying the signaling pathways and individual proteins affected at the post-translational level by radiation should shed valuable insight into the molecular mechanisms that regulate dose-dependent responses to radiation. PRINCIPAL FINDINGS: We have identified 7117 unique phosphopeptides (2566 phosphoproteins from control and irradiated (2 and 50 cGy primary human skin fibroblasts 1 h post-exposure. Semi-quantitative label-free analyses were performed to identify phosphopeptides that are apparently altered by radiation exposure. This screen identified phosphorylation sites on proteins with known roles in radiation responses including TP53BP1 as well as previously unidentified radiation-responsive proteins such as the candidate tumor suppressor SASH1. Bioinformatic analyses suggest that low and high doses of radiation affect both overlapping and unique biological processes and suggest a role for MAP kinase and protein kinase A (PKA signaling in the radiation response as well as differential regulation of p53 networks at low and high doses of radiation. CONCLUSIONS: Our results represent the most comprehensive analysis of the phosphoproteomes of human primary fibroblasts exposed to multiple doses of ionizing radiation published to date and provide a basis for the systems-level identification of biological processes, molecular pathways and individual proteins regulated in a dose dependent manner by ionizing radiation. Further study of these modified proteins and affected networks should help to define the molecular mechanisms that regulate biological responses to radiation at different radiation doses and elucidate the impact of low-dose radiation exposure on human health.

  3. Interaction of Ionizing Radiation, Genetically Active Chemicals, and Radiofrequency Radiation in Human and Rodent Cells

    Science.gov (United States)

    1990-12-01

    Martin L. Meltz, Ph.D. Patricia K. Holahan , Ph.D. Steven T. Smith, Ph.D. James J. Kerbacher, Ph.D. Victor Ciaravino, Ph.D. Department of Radiology PO...Chemicals, and Radiofrequency Radiation in Human and Rodent Cells 12 PERSONAL AUTHOR(S) Meltz. Martin L.; Holahan Patricia K.; Smith Steven Kerbacher...Potentiation of SCE Induction and Cell Killing by Adriamycin in CHO Cells (Ciaravino and Holahan , in preparation), showed that Adriamycin exposure at 410C

  4. Alteration of cytokine profiles in mice exposed to chronic low-dose ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Suk Chul [Radiation Health Research Institute, Korea Hydro and Nuclear Power Co., Ltd., 388-1, Ssangmun-dong, Dobong-gu, Seoul 132-703 (Korea, Republic of); Lee, Kyung-Mi [Global Research Lab, BAERI Institute, Department of Biochemistry and Molecular Biology, Korea University College of Medicine, Seoul 136-705 (Korea, Republic of); Kang, Yu Mi [Radiation Health Research Institute, Korea Hydro and Nuclear Power Co., Ltd., 388-1, Ssangmun-dong, Dobong-gu, Seoul 132-703 (Korea, Republic of); Kim, Kwanghee [Global Research Lab, BAERI Institute, Department of Biochemistry and Molecular Biology, Korea University College of Medicine, Seoul 136-705 (Korea, Republic of); Kim, Cha Soon; Yang, Kwang Hee; Jin, Young-Woo [Radiation Health Research Institute, Korea Hydro and Nuclear Power Co., Ltd., 388-1, Ssangmun-dong, Dobong-gu, Seoul 132-703 (Korea, Republic of); Kim, Chong Soon [Department of Nuclear Medicine, Haeundae Paik Hospital, Inje University, Busan 612-030 (Korea, Republic of); Kim, Hee Sun, E-mail: hskimdvm@khnp.co.kr [Radiation Health Research Institute, Korea Hydro and Nuclear Power Co., Ltd., 388-1, Ssangmun-dong, Dobong-gu, Seoul 132-703 (Korea, Republic of)

    2010-07-09

    While a high-dose of ionizing radiation is generally harmful and causes damage to living organisms, a low-dose of radiation has been shown to be beneficial in a variety of animal models. To understand the basis for the effect of low-dose radiation in vivo, we examined the cellular and immunological changes evoked in mice exposed to low-dose radiation at very low (0.7 mGy/h) and low (3.95 mGy/h) dose rate for the total dose of 0.2 and 2 Gy, respectively. Mice exposed to low-dose radiation, either at very low- or low-dose rate, demonstrated normal range of body weight and complete blood counts. Likewise, the number and percentage of peripheral lymphocyte populations, CD4{sup +} T, CD8{sup +} T, B, or NK cells, stayed unchanged following irradiation. Nonetheless, the sera from these mice exhibited elevated levels of IL-3, IL-4, leptin, MCP-1, MCP-5, MIP-1{alpha}, thrombopoietin, and VEGF along with slight reduction of IL-12p70, IL-13, IL-17, and IFN-{gamma}. This pattern of cytokine release suggests the stimulation of innate immunity facilitating myeloid differentiation and activation while suppressing pro-inflammatory responses and promoting differentiation of naive T cells into T-helper 2, not T-helper 1, types. Collectively, our data highlight the subtle changes of cytokine milieu by chronic low-dose {gamma}-radiation, which may be associated with the functional benefits observed in various experimental models.

  5. Induction of gene expression as a monitor of exposure to ionizing radiation.

    Science.gov (United States)

    Amundson, S A; Bittner, M; Meltzer, P; Trent, J; Fornace, A J

    2001-11-01

    The complex molecular responses to genotoxic stress are mediated by a variety of regulatory pathways. The transcription factor TP53 plays a central role in the cellular response to DNA-damaging agents such as ionizing radiation, but other pathways also play important roles. In addition, differences in radiation quality, such as the exposure to high-LET radiation that occurs during space travel, may influence the pattern of responses. The premise is developed that stress gene responses can be employed as molecular markers for radiation exposure using a combination of informatics and functional genomics approaches. Published studies from our laboratory have already demonstrated such transcriptional responses with doses of gamma rays as low as 2 cGy, and in peripheral blood lymphocytes (PBLs) irradiated ex vivo with doses as low as 20 cGy. We have also found several genes elevated in vivo 24 h after whole-body irradiation of mice with 20 cGy. Such studies should provide insight into the molecular responses to physiologically relevant doses, which cannot necessarily be extrapolated from high-dose studies. In addition, ongoing experiments are identifying large numbers of potential biomarkers using microarray hybridization and various irradiation protocols including expression at different times after exposure to low- and high-LET radiation. Computation-intensive informatics analysis methods are also being developed for management of the complex gene expression profiles resulting from these experiments. With further development of these approaches, it may be feasible to monitor changes in gene expression after low-dose radiation exposure and other physiological stresses that may be encountered during manned space flight, such as the planned mission to Mars.

  6. Surface characterization of gallium nitride modified with peptides before and after exposure to ionizing radiation in solution.

    Science.gov (United States)

    Berg, Nora G; Nolan, Michael W; Paskova, Tania; Ivanisevic, Albena

    2014-12-30

    An aqueous surface modification of gallium nitride was employed to attach biomolecules to the surface. The modification was a simple two-step process using a single linker molecule and mild temperatures. The presence of the peptide on the surface was confirmed with X-ray photoelectron spectroscopy. Subsequently, the samples were placed in water baths and exposed to ionizing radiation to examine the effects of the radiation on the material in an environment similar to the body. Surface analysis confirmed degradation of the surface of GaN after radiation exposure in water; however, the peptide molecules successfully remained on the surface following exposure to ionizing radiation. We hypothesize that during radiation exposure of the samples, the radiolysis of water produces peroxide and other reactive species on the sample surface. Peroxide exposure promotes the formation of a more stable layer of gallium oxyhydroxide which passivates the surface better than other oxide species.

  7. Ionization Parameter as a Diagnostic of Radiation and Wind Pressures in H II Regions and Starburst Galaxies

    CERN Document Server

    Yeh, Sherry C C

    2012-01-01

    The ionization parameter U is potentially useful for measuring radiation pressure feedback from massive star clusters, as it reflects the radiation-to-gas-pressure ratio and is readily derived from mid-infrared line ratios. We consider several effects which determine the apparent value of U in HII regions and galaxies. An upper limit is set by the compression of gas by radiation pressure. The pressure from stellar winds and the presence of neutral clumps both reduce U for a given radiation intensity. The most intensely irradiated regions are selectively dimmed by internal dust absorption of ionizing photons, inducing observational bias on galactic scales. We explore these effects analytically and numerically, and use them to interpret previous observational results. We find that radiation confinement sets the upper limit log_10 U = -1 seen in individual regions. Unresolved starbursts display a maximum value of ~ -2.3. While lower, this is also consistent with a large portion of their HII regions being radiati...

  8. The evaluation of non-ionizing radiation (near-infrared radiation) based medical imaging application: Diabetes foot

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Young Jin [Dept. of Radiological Science, Dongseo University, Busan (Korea, Republic of); Shin, Cheol Won; Ahn, Sung Min; Hong, Jun Yong; Ahn, Yun Jin; Lim, Cheong Hwan [Dept. of Radiological Science, Hanseo University, Seosan (Korea, Republic of)

    2016-09-15

    Near-infrared radiation (NIR) is non-ionizing, non-invasive, and deep tissue penetration in biological material, thereby increasing research interests as a medical imaging technique in the world. However, the use of current near-infrared medical image is extremely limited in Korea (ROK) since it is not well known among radiologic technologists and radiological researchers. Therefore to strengthen the knowledge for NIR medical imaging is necessary so as to prepare a qualified radiological professionals to serve medical images in high-quality on the clinical sites. In this study, an overview of the features and principles of N IR imaging was demonstrated. The latest research topics and worldwide research trends were introduced for radiologic technologist to reinforce their technical skills. In particular, wound care and diabetic foot which have high feasibility for clinical translation were introduced in order to contribute to accelerating NIR research for developing the field of radiological science.

  9. Radial dependence of ionization losses of protons of the Earth's radiation belts

    Science.gov (United States)

    Kovtyukh, A. S.

    2016-01-01

    Coulomb losses and charge exchange of protons are considered in detail. On the basis of modern models of the plasmasphere and the exosphere, the radial dependences of the rates of ionization losses of protons, with μ from 0.3 to 10 keV nT-1, of the Earth's radiation belts near the equatorial plane are calculated for quiet periods. For calculation of Coulomb losses of protons we used data of ISEE-1 satellite (protons with energy from 24 to 2081 keV) on L from 3 to 9, data of Explorer-45 satellite (protons with energy from 78.6 to 872 keV) on L from 3 to 5 and data of CRRES satellite (protons with energy from 1 to 100 MeV) on L ≤ 3 (L is the McIlwain parameter). It is shown that with decreasing L the rate of ionization losses of protons of the radiation belts is reduced; for protons with μ > 1.2 keV nT-1 in a narrow region (ΔL ˜ 0.5) in the district of plasmapause in this dependence may form a local minimum of the rate. We found that the dependence from μ of the boundary on L between Coulomb losses and charge exchange of the trapped protons with hydrogen atoms is well approximated by the function Lb = 4.71μ0.32, where [μ] = keV nT-1. Coulomb losses dominate at L Lb(μ) dominates charge exchange of protons. We found the effect of subtracting the Coulomb losses from the charge exchange of protons of the radiation belts at low μ and L, which can simulate a local source of particles.

  10. p21 is Responsible for Ionizing Radiation-induced Bypass of Mitosis

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xu Rui; LIU Yong Ai; SUN Fang; LI He; LEI Su Wen; WANG Ju Fang

    2016-01-01

    Objective To explore the role of p21 in ionizing radiation-induced changes in protein levels during the G2/M transition and long-term G2 arrest. Methods Protein expression levels were assessed by western blot in the human uveal melanoma 92-1 cells after treatment with ionizing radiation. Depletion of p21 was carried out by employing the siRNA technique. Cell cycle distribution was determined by flow cytometry combined with histone H3 phosphorylation at Ser28, an M-phase marker. Senescence was assessed by senescence-associated-β-galactosidase (SA-β-gal) staining combined with Ki67 staining, a cell proliferation marker. Results Accompanying increased p21, the protein levels of G2/M transition genes declined significantly in 92-1 cells irradiated with 5 Gy of X-rays. Furthermore, these irradiated cells were blocked at the G2 phase followed by cellular senescence. Depletion of p21 rescued radiation-induced G2 arrest as demonstrated by the upregulation of G2/M transition kinases, as well as the high expression of histone H3 phosphorylated at Ser28. Knockdown of p21 resulted in entry into mitosis of irradiated 92-1 cells. However, cells with serious DNA damage failed to undergo cytokinesis, leading to the accumulation of multinucleated cells. Conclusion Our results indicated that p21 was responsible for the downregulation of G2/M transition regulatory proteins and the bypass of mitosis induced by irradiation. Downregulation of p21 by siRNA resulted in G2-arrested cells entering into mitosis with serious DNA damage. This is the first report on elucidating the role of p21 in the bypass of mitosis.

  11. Radial dependence of ionization losses of protons of the Earth's radiation belts

    Energy Technology Data Exchange (ETDEWEB)

    Kovtyukh, A.S. [Moscow State Univ. (Russian Federation). Skobeltsyn Inst. of Nuclear Phyiscs

    2016-04-01

    Coulomb losses and charge exchange of protons are considered in detail. On the basis of modern models of the plasmasphere and the exosphere, the radial dependences of the rates of ionization losses of protons, with μ from 0.3 to 10 keV nT{sup -1}, of the Earth's radiation belts near the equatorial plane are calculated for quiet periods. For calculation of Coulomb losses of protons we used data of ISEE-1 satellite (protons with energy from 24 to 2081 keV) on L from 3 to 9, data of Explorer-45 satellite (protons with energy from 78.6 to 872 keV) on L from 3 to 5 and data of CRRES satellite (protons with energy from 1 to 100 MeV) on L ≤ 3 (L is the McIlwain parameter). It is shown that with decreasing L the rate of ionization losses of protons of the radiation belts is reduced; for protons with μ > 1.2 keV nT{sup -1} in a narrow region (ΔL ∝ 0.5) in the district of plasmapause in this dependence may form a local minimum of the rate. We found that the dependence from μ of the boundary on L between Coulomb losses and charge exchange of the trapped protons with hydrogen atoms is well approximated by the function L{sub b} = 4.71μ{sup 0.32}, where [μ] = keV nT{sup -1}. Coulomb losses dominate at L < L{sub b}(μ), and at L > L{sub b}(μ) dominates charge exchange of protons. We found the effect of subtracting the Coulomb losses from the charge exchange of protons of the radiation belts at low μ and L, which can simulate a local source of particles.

  12. Phosphoproteomics profiling of human skin fibroblast cells reveals pathways and proteins affected by low doses of ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Feng; Waters, Katrina M.; Miller, John H.; Gritsenko, Marina A.; Zhao, Rui; Du, Xiuxia; Livesay, Eric A.; Purvine, Samuel O.; Monroe, Matthew E.; Wang, Yingchun; Camp, David G.; Smith, Richard D.; Stenoien, David L.

    2010-11-30

    Background: High doses of ionizing radiation result in biological damage, however the precise relationships between long term health effects, including cancer, and low dose exposures remain poorly understood and are currently extrapolated using high dose exposure data. Identifying the signaling pathways and individual proteins affected at the post-translational level by radiation should shed valuable insight into the molecular mechanisms that regulate dose dependent responses to radiation. Principle Findings: We have identified 6845 unique phosphopeptides (2566 phosphoproteins) from control and irradiated (2 and 50 cGy) primary human skin fibroblasts one hour post-exposure. Dual statistical analyses based on spectral counts and peak intensities identified 287 phosphopeptides (from 231 proteins) and 244 phosphopeptides (from 182 proteins) that varied significantly following exposure to 2 and 50 cGy respectively. This screen identified phosphorylation sites on proteins with known roles in radiation responses including TP53BP1 as well as previously unidentified radiation responsive proteins such as the candidate tumor suppressor SASH1. Bioinformatics analyses suggest that low and high doses of radiation affect both overlapping and unique biological processes and suggest a role of MAP kinase and protein kinase A (PKA) signaling in the radiation response as well as differential regulation of p53 networks at low and high doses of radiation. Conlcusions: Our results represent the most comprehensive analysis of the phosphoproteomes of human primary fibroblasts exposed to multiple doses of ionizing radiation published to date and provides a basis for the systems level identification of biological processes, molecular pathways and individual proteins regulated in a dose dependent manner by ionizing radiation. Further study of these modified proteins and affected networks should help to define the molecular mechanisms that regulate biological responses to radiation at

  13. Astrophysics Decoding the cosmos

    CERN Document Server

    Irwin, Judith A

    2007-01-01

    Astrophysics: Decoding the Cosmos is an accessible introduction to the key principles and theories underlying astrophysics. This text takes a close look at the radiation and particles that we receive from astronomical objects, providing a thorough understanding of what this tells us, drawing the information together using examples to illustrate the process of astrophysics. Chapters dedicated to objects showing complex processes are written in an accessible manner and pull relevant background information together to put the subject firmly into context. The intention of the author is that the book will be a 'tool chest' for undergraduate astronomers wanting to know the how of astrophysics. Students will gain a thorough grasp of the key principles, ensuring that this often-difficult subject becomes more accessible.

  14. Characterization of interpenetrating networks of acrylic acid (AAc) and N-isopropylacrylamide (NIPAAm) synthesized by ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Adem, E. [Departamento de Fisica Experimental, Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Mexico DF 04510 (Mexico); Burillo, G. [Departamento de Quimica de Radiaciones y Radioquimica, Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Mexico DF 04510 (Mexico)], E-mail: burillo@nucleares.unam.mx; Bucio, E. [Departamento de Quimica de Radiaciones y Radioquimica, Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Mexico DF 04510 (Mexico); Magana, C. [Departamento de Fisica Experimental, Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Mexico DF 04510 (Mexico); Avalos-Borja, M. [Centro de Nanociencias y Nanotecnologia, Universidad Nacional Autonoma de Mexico, A. Postal 2681, Ensenada, B.C. 22800 (Mexico)

    2009-07-15

    Interpenetrating networks of poly(acrylic acid) (PAAc) and poly(N-isopropylacrylamide) (PNIPAAm) were synthesized in two consecutive steps utilizing ionizing radiation in the first step and chemical reaction in the second step. The first network of PAAc hydrogel was formed by ionizing radiation (gamma or electron beam). The secondary gel of PNIPAAm was synthesized directly within the primary gel of PAAc from an aqueous solution of N-isopropylacrylamide (NIPAAm) containing a crosslinking agent, accelerator and redox initiator. The interpenetrating networks (IPNs) were characterized morphologically by scanning electron microscopy (SEM), and their thermal behavior was analyzed by differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA)

  15. Effect of the ionizing radiation on the Staphylococcal enterotoxins and Staphylococcus aureus in mechanically deboned chicken meat

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Heliana de Azevedo; Rocha, Claudia Regina Gomes; Roque, Claudio Vitor [Laboratorio de Pocos de Caldas (LAPOC/CNEN-MG), MG (Brazil)]. E-mail: hgomes@cnen.gov.br; crgrocha@gmail.com; cvroque@cnen.gov.br; Pereira, Jose Luiz [Universidade Estadual de Campinas, SP (Brazil). Dept. de Ciencias de Alimentos]. E-mail: pereira@fea.unicamp.br

    2007-07-01

    Ionizing radiation was employed in order to reduce contamination of mechanically deboned chicken meat (MDCM) by Staphylococcus aureus and also to evaluate the effect of the ionizing radiation on the staphylococcal enterotoxins. The microbiological analyses were carried out on MDCM refrigerated (+ 2 deg C) for 12 days. Irradiation treatments of MDCM with doses of 3.0 kGy and 4.0 kGy were capable of reducing the contamination by Staphylococcus aureus and reducing the amounts of staphylococcal enterotoxin, which might be present in this raw material. (author)

  16. Space charge effect measurements for a multi-channel ionization chamber used for synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Nasr, Amgad

    2012-07-18

    In vivo coronary angiography is one of the techniques used to investigate the heart diseases, by using catheter to inject a contrast medium of a given absorption coefficient into the heart vessels. Taking X-ray images produced by X-ray tube or synchrotron radiation for visualizing the blood in the coronary arteries. As the synchrotron radiation generated by the relativistic charged particle at the bending magnets, which emits high intensity photons in comparison with the X-ray tube. The intensity of the synchrotron radiation is varies with time. However for medical imaging it's necessary to measure the incoming intensity with the integrated time. The thesis work includes building a Multi-channel ionization chamber which can be filled with noble gases N{sub 2}, Ar and Xe with controlled inner pressure up to 30 bar. This affects the better absorption efficiency in measuring the high intensity synchrotron beam fluctuation. The detector is a part of the experimental setup used in the k-edge digital subtraction angiography project, which will be used for correcting the angiography images taken by another detector at the same time. The Multi-channel ionization chamber calibration characteristics are measured using 2 kW X-ray tube with molybdenum anode with characteristic energy of 17.44 keV. According to the fast drift velocity of the electrons relative to the positive ions, the electrons will be collected faster at the anode and will induce current signals, while the positive ions is still drifting towards the cathode. However the accumulation of the slow ions inside the detector disturbs the homogeneous applied electric field and leads to what is known a space charge effect. In this work the space charge effect is measured with very high synchrotron photons intensity from EDR beam line at BESSYII. The strong attenuation in the measured amplitude signal occurs when operating the chamber in the recombination region. A plateau is observed at the amplitude signal when

  17. Connecting the dots: a correlation between ionizing radiation and cloud mass-loss rate traced by optical integral field spectroscopy

    Science.gov (United States)

    McLeod, A. F.; Gritschneder, M.; Dale, J. E.; Ginsburg, A.; Klaassen, P. D.; Mottram, J. C.; Preibisch, T.; Ramsay, S.; Reiter, M.; Testi, L.

    2016-11-01

    We present an analysis of the effect of feedback from O- and B-type stars with data from the integral field spectrograph Multi Unit Spectroscopic Explorer (MUSE) mounted on the Very Large Telescope of pillar-like structures in the Carina Nebular Complex, one of the most massive star-forming regions in the Galaxy. For the observed pillars, we compute gas electron densities and temperatures maps, produce integrated line and velocity maps of the ionized gas, study the ionization fronts at the pillar tips, analyse the properties of the single regions, and detect two ionized jets originating from two distinct pillar tips. For each pillar tip, we determine the incident ionizing photon flux Q0, pil originating from the nearby massive O- and B-type stars and compute the mass-loss rate dot{M} of the pillar tips due to photoevaporation caused by the incident ionizing radiation. We combine the results of the Carina data set with archival MUSE data of a pillar in NGC 3603 and with previously published MUSE data of the Pillars of Creation in M16, and with a total of 10 analysed pillars, find tight correlations between the ionizing photon flux and the electron density, the electron density and the distance from the ionizing sources, and the ionizing photon flux and the mass-loss rate. The combined MUSE data sets of pillars in regions with different physical conditions and stellar content therefore yield an empirical quantification of the feedback effects of ionizing radiation. In agreement with models, we find that dot{M}∝ Q_0,pil^{1/2}.

  18. Environmental standards for ionizing radiation: theoretical basis for dose-response curves.

    Science.gov (United States)

    Upton, A C

    1983-10-01

    The types of injury attributable to ionizing radiation are subdivided, for purposes of risk assessment and radiological protection, into two broad categories: stochastic effects and nonstochastic effects. Stochastic effects are viewed as probablistic phenomena, varying in frequency but not severity as a function of the dose, without any threshold; nonstochastic effects are viewed as deterministic phenomena, varying in both frequency and severity as a function of the dose, with clinical thresholds. Included among stochastic effects are heritable effects (mutations and chromosome aberrations) and carcinogenic effects. Both types of effects are envisioned as unicellular phenomena which can result from nonlethal injury of individual cells, without the necessity of damage to other cells. For the induction of mutations and chromosome aberrations in the low-to-intermediate dose range, the dose-response curve with high-linear energy transfer (LET) radiation generally conforms to a linear nonthreshold relationship and varies relatively little with the dose rate. In contrast, the curve with low-LET radiation generally conforms to a linear-quadratic relationship, rising less steeply than the curve with high-LET radiation and increasing in slope with increasing dose and dose rate. The dose-response curve for carcinogenic effects varies widely from one type of neoplasm to another in the intermediate-to-high dose range, in part because of differences in the way large doses of radiation can affect the promotion and progression of different neoplasms. Information about dose-response relations for low-level irradiation is fragmentary but consistent, in general, with the hypothesis that the neoplastic transformation may result from mutation, chromosome aberration or genetic recombination in a single susceptible cell.

  19. Multi-Level Effects of Low Dose Rate Ionizing Radiation on Southern Toad, Anaxyrus [Bufo] terrestris.

    Directory of Open Access Journals (Sweden)

    Karolina Stark

    Full Text Available Despite their potential vulnerability to contaminants from exposure at multiple life stages, amphibians are one of the least studied groups of vertebrates in ecotoxicology, and research on radiation effects in amphibians is scarce. We used multiple endpoints to assess the radiosensitivity of the southern toad (Anaxyrus [Bufo] terrestris during its pre-terrestrial stages of development -embryonic, larval, and metamorphic. Toads were exposed, from several hours after oviposition through metamorphosis (up to 77 days later, to four low dose rates of 137Cs at 0.13, 2.4, 21, and 222 mGy d-1, resulting in total doses up to 15.8 Gy. Radiation treatments did not affect hatching success of embryos, larval survival, or the length of the larval period. The individual family variation in hatching success of embryos was larger than the radiation response. In contrast, newly metamorphosed individuals from the higher dose-rate treatments had higher mass and mass/length body indices, a measure which may relate to higher post-metamorphic survival. The increased mass and index at higher dose rates may indicate that the chronic, low dose rate radiation exposures triggered secondary responses. Additionally, the increases in growth were linked to a decrease in DNA damage (as measured by the Comet Assay in red blood cells at a dose rate of 21 mGy d-1 and a total dose of 1.1 Gy. In conclusion, the complex effects of low dose rates of ionizing radiation may trigger growth and cellular repair mechanisms in amphibian larvae.

  20. Involvement of MAPK proteins in bystander effects induced by chemicals and ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Asur, Rajalakshmi [Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Suite 1370, Detroit, MI 48202-3917 (United States); Balasubramaniam, Mamtha [Research Institute - Biostatistics, William Beaumont Hospital, 3911 W. Thirteen Mile Road, Royal Oak, MI 48073 (United States); Marples, Brian [Department of Radiation Oncology, William Beaumont Hospital, 3811 W. Thirteen Mile Road, Royal Oak, MI 48073 (United States); Thomas, Robert A. [Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Suite 1370, Detroit, MI 48202-3917 (United States); Tucker, James D., E-mail: jtucker@biology.biosci.wayne.edu [Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Suite 1370, Detroit, MI 48202-3917 (United States)

    2010-04-01

    Many studies have examined bystander effects induced by ionizing radiation, however few have evaluated the ability of chemicals to induce similar effects. We previously reported the ability of two chemicals, mitomycin C (MMC) and phleomycin (PHL) to induce bystander effects in normal human lymphoblastoid cell lines. The focus of the current study was to determine the involvement of the MAPK proteins in bystander effects induced by physical and chemical DNA damaging agents and to evaluate the effects of MAPK inhibition on bystander-induced caspase 3/7 activation. The phosphorylation levels of the MAPK proteins ERK1/2, JNK, and p38, were measured from 1 to 24 h following direct or bystander exposure to MMC, PHL or radiation. We observed transient phosphorylation, at early time points, of all 3 proteins in bystander cells. We also evaluated the effect of MAPK inhibition on bystander-induced caspase 3/7 activity to determine the role of MAPK proteins in bystander-induced apoptosis. We observed bystander-induced activation of caspase 3/7 in bystander cells. Inhibition of MAPK proteins resulted in a decrease in caspase 3/7 activity at the early time points, and the caspase activity increased (in the case of ERK inhibition) or returned to basal levels (in the case of JNK or p38 inhibition) between 12 and 24 h. PHL is considered to be a radiomimetic agent, however in the present study PHL behaved more like a chemical and not like radiation in terms of MAPK phosphorylation. These results point to the involvement of MAPK proteins in the bystander effect induced by radiation and chemicals and provide additional evidence that this response is not limited to radiation but is a generalized stress response in cells.

  1. Carcinogenesis and low-level ionizing radiation with special reference to lung cancer and exposure to radon daughters

    Energy Technology Data Exchange (ETDEWEB)

    Fabrikant, J.I.

    1982-04-01

    Of the important health effects of ionizing radiation, three important late effects - carcinogenesis, teratogenesis and mutagenesis are of greatest concern. This is because any exposure, even at low levels, carries some risk of such deleterious effects. As the dose of radiation increases above very low levels, the risk of health effects increases. Cancer-induction is the most important late somatic effect of low-dose ionizing radiation. Solid cancers, rather than leukemia, are principal late effects in exposed individuals. Tissues vary greatly in their susceptibility to radiation carcinogenesis. The most frequently occurring radiation-induced cancers in man include, in decreasing order of susceptibility: the female breast, the thyroid gland, the blood-forming tissues, the lung, certain organs of the gastrointestinal tract, and the bones. A number of biological and physical factors affect the cancer risk, such as age, sex, life-style, LET, and RBE. Despite uncertainty about low-level radiation risks, regulatory and advisory bodies must set standards for exposure, and individuals need information to be able to make informed judgments for themselves. From the point of view of the policy maker, the overriding concern is the fact that small doses of radiation can cause people to have more cancers than would otherwise be expected. While concern for all radiation effects exists, our human experience is limited to cancer-induction in exposed populations. This discussion is limited to cancer risk estimation and decision-making in relation to the health effects on populations of exposure to low levels of ionizing radiation. Here, low-level radiation will refer to yearly whole-body doses up to 5 rems or 0.05 Sv, or to cumulative doses up to 50 rems or 0.5 Sv from low-LET radiation and from high-LET radiation. (ERB)

  2. Oligodendroglial response to ionizing radiation: Dose and dose-rate response

    Energy Technology Data Exchange (ETDEWEB)

    Levy, R.P.

    1991-12-01

    An in vitro system using neuroglia from neonatal rat brain was developed to examine the morphologic, immunocytochemical and biochemical response of oligodendroglia to ionizing radiation. Following acute {gamma}-irradiation at day-in-culture (DIC) 8, oligodendrocyte counts at DIC 14 were 55% to 65% of control values after 2 Gy, and 29% to 36% after 5 Gy. Counts increased to near-normal levels at DIC 21 in the 2 Gy group and to 75% of normal in the 5 Gy group. Myelin basic protein levels (MBP) at DIC 14 were 60% of control values after 2 Gy, and 40% after 5 Gy. At DIC 21, MBP after 2 Gy was 45% greater than that observed at DIC 14, but MBP, as a fraction of age-matched control values, dropped from 60% to 50%. Following 5 Gy, absolute MBP changed little between DIC 14 and DIC 21, but decreased from 40% to 25% of control cultures. The response to split-dose irradiation indicated that nearly all sublethal damage in the oligodendrocyte population (and its precursors) was repaired within 3 h to 4 h. A new compartmental cell model for radiation response in vitro of the oligodendrocyte population is proposed and examined in relation to the potential reaction to radiation injury in the brain.

  3. Effect of ionizing radiation on the physical biology of head and neck squamous cell carcinoma cells.

    Science.gov (United States)

    Baker-Groberg, Sandra M; Bornstein, Sophia; Zilberman-Rudenko, Jevgenia; Schmidt, Mark; Tormoen, Garth W; Kernan, Casey; Thomas, Charles R; Wong, Melissa H; Phillips, Kevin G; McCarty, Owen J T

    2015-09-01

    Head and neck squamous cell carcinoma (HNSCC) is the sixth leading cause of cancer worldwide. Although there are numerous treatment options for HNSCC, such as surgery, cytotoxic chemotherapy, molecularly targeted systemic therapeutics, and radiotherapy, overall survival has not significantly improved in the last 50 years. This suggests a need for a better understanding of how these cancer cells respond to current treatments in order to improve treatment paradigms. Ionizing radiation (IR) promotes cancer cell death through the creation of cytotoxic DNA lesions, including single strand breaks, base damage, crosslinks, and double strand breaks (DSBs). As unrepaired DSBs are the most cytotoxic DNA lesion, defining the downstream cellular responses to DSBs are critical for understanding the mechanisms of tumor cell responses to IR. The effects of experimental IR on HNSCC cells beyond DNA damage in vitro are ill-defined. Here we combined label-free, quantitative phase and fluorescent microscopy to define the effects of IR on the dry mass and volume of the HNSCC cell line, UM-SCC-22A. We quantified nuclear and cytoplasmic subcellular density alterations resulting from 8 Gy X-ray IR and correlated these signatures with DNA and γ-H2AX expression patterns. This study utilizes a synergistic imaging approach to study both biophysical and biochemical alterations in cells following radiation damage and will aid in future understanding of cellular responses to radiation therapy.

  4. Comparison of functional and morphological deficits in the rat after gestational exposure to ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Norton, S.; Kimler, B.F.

    1988-07-01

    Ionizing radiation is a precise tool for altering formation of the developing cerebral cortex of the fetal rat. Whole body exposure of the pregnant rat on gestational day 13, 15 or 17 to 1.0 Gy of gamma radiation resulted in maximum thinning of the cortex on days 15 and 17. In the preweaning period, functional tests (negative geotaxis, reflex suspension, continuous corridor and gait) were most affected by irradiation gestational day 15, as was body weight. When a lower dose of radiation (0.75 Gy) was used on gestational day 15, the damage to the cortex was much less but behavioral changes were still present. Frontal, parietal and occipital areas of the cortex were approximately equally affected. Using stepwise multiple regression analysis, the linkage of functional tests and cortical thickness was examined. Functional variables which were most commonly included as predictors of frontal and parietal cortex were negative geotaxis and continuous corridor. Occipital cortical layers were not predicted by behavioral variables. In predicting function using cortical variables, frontal cortex was better than parietal and occipital cortex was the poorest predictor.

  5. A new mechanism of ionizing radiation detection for positron emission tomography: modulation of optical properties

    Science.gov (United States)

    Tao, Li; Daghighian, Henry M.; Levin, Craig S.

    2016-10-01

    Using conventional scintillation detection, the fundamental limit in positron emission tomography (PET) annihilation photon pair coincidence time resolution is strongly dependent on the inherent temporal variances generated during the scintillation process, yielding an intrinsic physical limit of around 100 ps. On the other hand, modulation mechanisms of a material's optical properties as exploited in the optical telecommunications industry can be orders of magnitude faster. In this paper we borrow from the concept of optics pump-probe measurement to study whether ionizing radiation can also produce fast modulations of optical properties, which can be utilized as a novel method for radiation detection. We show that a refractive index modulation of approximately 5x10-6 is induced by interactions in a cadmium telluride (CdTe) crystal from a 511 keV photon source. Furthermore, using additional radionuclide sources, we show that the amplitude of the optical modulation signal varies linearly with both the radiation source flux rate and average photon energy.

  6. A Monolithic active pixel sensor for ionizing radiation using a 180nm HV-SOI process

    CERN Document Server

    Hemperek, Tomasz; Krüger, Hans; Wermes, Norbert

    2014-01-01

    An improved SOI-MAPS (Silicon On Insulator Monolithic Active Pixel Sensor) for ionizing radiation based on Partially Depleted High Voltage SOI technology (PD-SOI) has been developed. Similar to existing Fully Depleted SOI-based (FD-SOI) MAPS, a buried silicon oxide inter-dielectric (BOX) layer is used to separate the CMOS electronics from the handle wafer which is used as a depleted charge collection layer while FD-SOI MAPS suffer from radiation damage such as transistor threshold voltage shifts due to charge traps in the oxide layers and charge states created at the silicon oxide boundaries (back gate effect). The XFAB 180-nm HV-SOI technology offers an additional isolation by deep non-depleted implant between the BOX layer and the active circuitry witch mitigates this problem. Therefore we see in this technology a high potential to implement radiation-tolerant MAPS with fast charge collection property. The design and measurement results from a first prototype are presented including charge collection in neu...

  7. Ionizing radiation effects on electrical and reliability characteristics of sputtered Ta2O5/Si interface

    Science.gov (United States)

    Rao, Ashwath; Verma, Ankita; Singh, B. R.

    2015-06-01

    This paper describes the effect of ionizing radiation on the interface properties of Al/Ta2O5/Si metal oxide semiconductor (MOS) capacitors using capacitance-voltage (C-V) and current-voltage (I-V) characteristics. The devices were irradiated with X-rays at different doses ranging from 100 rad to 1 Mrad. The leakage behavior, which is an important parameter for memory applications of Al/Ta2O5/Si MOS capacitors, along with interface properties such as effective oxide charges and interface trap density with and without irradiation has been investigated. Lower accumulation capacitance and shift in flat band voltage toward negative value were observed in annealed devices after exposure to radiation. The increase in interfacial oxide layer thickness after irradiation was confirmed by Rutherford Back Scattering measurement. The effect of post-deposition annealing on the electrical behavior of Ta2O5 MOS capacitors was also investigated. Improved electrical and interface properties were obtained for samples deposited in N2 ambient. The density of interface trap states (Dit) at Ta2O5/Si interface sputtered in pure argon ambient was higher compared to samples reactively sputtered in nitrogen-containing plasma. Our results show that reactive sputtering in nitrogen-containing plasma is a promising approach to improve the radiation hardness of Ta2O5/Si MOS devices.

  8. Crosslinking of polysaccharides in room temperature ionic liquids by ionizing radiation

    Science.gov (United States)

    Kimura, Atsushi; Nagasawa, Naotsugu; Shimada, Akihiko; Taguchi, Mitsumasa

    2016-07-01

    Crosslinking of polysaccharides in room temperature ionic liquids (RTILs) by ionizing radiation were investigated by the scavenging method, fluorescent and X-ray photoelectron spectroscopy (XPS) analysis. Radiation chemical yields of hydroxyl radicals inducing the crosslinking of cellulose were estimated with phenol as a scavenger, and increased with water content in 1-ethyl-3-methylimidazolium acetate (EMI-acetate). Cellulose gel was also produced in fluorescent carboxylate-based RTILs, 1,3-dibutylimidazolium acetate (DBI-acetate). Light emission from DBI-acetate in cellulose gel was observed and 20-nm red shifted at a maximum wavelength of 415 nm when excited at 323 nm. Expected elements of carbon and oxygen were detected in neat cellulose by XPS, while additional nitrogen was detected in radiation-crosslinked cellulose gel produced in EMI-acetate. These results indicate that RTILs is incorporated in the cellulose gel. Chitin gel was first obtained in 1-butyl-3-methyimidazolium chloride by γ-ray irradiations, and its gel fraction increased with the dose and reached 86% at 60 kGy.

  9. A promising new mechanism of ionizing radiation detection for positron emission tomography: modulation of optical properties

    Science.gov (United States)

    Tao, Li; Daghighian, Henry M.; Levin, Craig S.

    2016-11-01

    Using conventional scintillation detection, the fundamental limit in positron emission tomography (PET) time resolution is strongly dependent on the inherent temporal variances generated during the scintillation process, yielding an intrinsic physical limit for the coincidence time resolution of around 100 ps. On the other hand, modulation mechanisms of the optical properties of a material exploited in the optical telecommunications industry can be orders of magnitude faster. In this paper we borrow from the concept of optics pump-probe measurement to for the first time study whether ionizing radiation can produce modulations of optical properties, which can be utilized as a novel method for radiation detection. We show that a refractive index modulation of approximately 5× {{10}-6} is induced by interactions in a cadmium telluride (CdTe) crystal from a 511 keV photon source. Furthermore, using additional radionuclide sources, we show that the amplitude of the optical modulation signal varies linearly with both the detected event rate and average photon energy of the radiation source.

  10. Morphological analysis of amnion stored in glycerol sterilized with different doses of ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Fernando Augusto N.; Santin, Stefany P.; Martino Junior, Antonio C.; Machado, Luci Diva B.; Mathor, Monica B., E-mail: fernandonevessoares@yahoo.com.br [Instituto de Pesquisas Energeticas e Nucleares (CTR/IPEN/CNEN-SP), Sao Paulo, RJ (Brazil). Centro de Tecnologia das Radiacoes

    2013-07-01

    The amniotic membrane (AM) is the innermost layer of the fetal membranes (placenta), widely used in transplantation being a tissue that combines anti-inflammatory, antimicrobial and antifibrotic, and limited immunogenicity. The tissue can be used a bandage biological for treatment of burns and skin wounds, chronic ulcers, reconstructions from different body areas, including ophthalmic repairs. In the last decades the amniotic membrane has been used widely also as a carrier substrate to transfer tissues cultured 'in vitro'. The use of fresh membrane has some limitations, the main ones are being necessary your quick use and the inability to obtain full security for certain infections. Other types of preservation require a processing thereof. The radiosterilization is an alternative for ensuring quality and safety of tissues used in transplants, and other clinical applications in order to minimize the risk of contamination of the receptor tissue. Therefore, the objective of this study was to test various doses of radiation using two sources of ionizing radiation: the cobalt-60 irradiator Gamma and Electron Beam Accelerator (E.B.). A tissue analysis was done by visual and tactile qualitative analysis, semi-quantitative (solid colorimetry) and light microscopy to observe morphological and physic-chemical changes after the irradiation of AM preserved in glycerol, comparing the results obtained with the sample not irradiated. It was noted that at higher doses, for both radiation sources, irradiated membranes suffered greater color change, becoming yellowish and thereby reducing their initial malleability. (author)

  11. A Monolithic Active Pixel Sensor for ionizing radiation using a 180 nm HV-SOI process

    Science.gov (United States)

    Hemperek, Tomasz; Kishishita, Tetsuichi; Krüger, Hans; Wermes, Norbert

    2015-10-01

    An improved SOI-MAPS (Silicon On Insulator Monolithic Active Pixel Sensor) for ionizing radiation based on thick-film High Voltage SOI technology (HV-SOI) has been developed. Similar to existing Fully Depleted SOI-based (FD-SOI) MAPS, a buried silicon oxide inter-dielectric (BOX) layer is used to separate the CMOS electronics from the handle wafer which is used as a depleted charge collection layer. FD-SOI MAPS suffers from radiation damage such as transistor threshold voltage shifts due to charge traps in the oxide layers and charge states created at the silicon oxide boundaries (back gate effect). The X-FAB 180-nm HV-SOI technology offers an additional isolation by deep non-depleted implant between the BOX layer and the active circuitry which mitigates this problem. Therefore we see in this technology a high potential to implement radiation-tolerant MAPS with fast charge collection property. The design and measurement results from a first prototype are presented including charge collection in neutron irradiated samples.

  12. Structural aspects of crotoxin modified by ionizing radiation; Aspectos estruturais da crotoxina modificada pela radiacao ionizante

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Karina Corleto de; Albero, Felipe Guimaraes; Zezell, Denise Maria; Spencer, Patrick Jack; Nascimento, Nanci do, E-mail: kcorleto@usp.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2010-03-15

    Ionizing radiation has proven to be an excellent tool for reducing the toxicity of venoms and isolated toxins, resulting in better immunogens for serum production, the only effective treatment in case of snake bites, and contributing to the welfare of serum-producing animals. Since the action of gamma radiation of venoms and toxins has not been yet fully clarified from the structural point of view, we proposed in this paper, to characterize the crotoxin, a venom protein of the species Crotalus durissus terrificus by Circular Dichroism (CD) and Infrared Spectroscopy (FTIR) techniques. After chromatographic techniques, crotoxin was irradiated with 2.0 kGy ({sup 60}Co source). The CD spectra obtained of native and irradiated crotoxin solutions showed changes between the samples in characteristic regions of -sheet and-helix . The Infrared analyse showed expressive changes in the spectra of the native and irradiated crotoxin (amide I band region). These tests showed that crotoxin when subjected to gamma radiation, showed changes in their structural conformation compared with the samples in the native state. Such changes probably occur in the secondary structure and may explain its neurotoxic activity loss. (author)

  13. Influence of Ionizing Radiation on Stromal-Epithelial Intercellular Communication in Esophageal Carcinogenesis

    Science.gov (United States)

    Patel, Zarana S.; Kalabis, Jiri; Rustgi, Anil K.; Cucinotta, Francis A.; Huff, Janice L.

    2010-01-01

    Esophageal cancer is the 6th leading cause of cancer death worldwide. Its development is associated with a variety of risk factors including tobacco use, heavy alcohol consumption, human papilloma virus infection, and certain dietary factors such as trace mineral and vitamin deficiencies. An association with ionizing radiation exposure is revealed by the high excess relative risk for squamous cell carcinoma of the esophagus observed in the survivors of the atomic bomb detonations in Japan. It is also seen as a secondary malignancy in patients who received radiotherapy for breast and thoracic cancers; additionally, patients with head/neck and oral squamous cell cancers are at increased risk for metachronous esophageal squamous cell cancers. This malignancy is rapidly fatal, mainly because it remains asymptomatic until late, advanced stages when the disease is rarely curable. The stromal microenvironment plays an essential role in the maintenance and modulation of normal epithelial cell growth and differentiation and cross talk between the epithelial and stromal compartments can influence many aspects of malignant progression, including tumor cell proliferation, migration, invasion and recruitment of new blood vessels. To test the hypothesis that radiation exposure plays a role in esophageal carcinogenesis via non-targeted mechanisms involving stromal-epithelial cell communication, we are studying radiation effects on hTERT-immortalized human esophageal epithelial cells and genetic variants grown in co-culture with human esophageal stromal fibroblasts (Okawa et al., Genes & Dev. 2007. 21: 2788-2803). We examined how radiation treatment of stromal fibroblasts affected epithelial migration and invasion, behaviors associated with cancer promotion and progression. Chemotactic and haptotactic migration of epithelial cells stimulated by conditioned media from irradiated fibroblasts was measured using assays conducted in Transwell cell culture chambers. Our results using

  14. Evaluation of dosimetric characteristics of multi-leaf and conventional collimated radiation fields using a scanning liquid ionization chamber EPID.

    Science.gov (United States)

    Mohammadi, M; Bezak, E

    2008-12-01

    The characteristics of radiation fields set up using conventional and Multi-Leaf collimators were investigated using a Scanning Liquid Ionization Chamber Electronic Portal Imaging Device (SLIC-EPID). Results showed that the radiation fields set up using MLCs are generally larger than those set up using conventional collimators. A significant difference was observed between the penumbra width for conventional and MLC radiation fields. SLIC-EPID was found to be a sensitive device to evaluate the characteristics of the radiation fields generated with MLCs.

  15. The Australasian radiation protection society's position statement on risks from low levels of ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Don, Higson; Ches, Mason; Andrew, McEwan; Peter, Burns; Riaz, Akber; Ron, Cameron; Pamela, Sykes; Joe, Young [Australasian Radiation Protection Society (Australia)

    2006-07-01

    At its Annual General Meeting in 2004, the Australasian Radiation Protection Society (A.R.P.S.) set up a working group to draft a statement of the Society's position on risks from low levels of exposure to ionizing radiation. The resulting position statement was adopted by the Society at its Annual General Meeting in 2005. Its salient features are as follows: First, there is insufficient evidence to establish a dose-effect relationship for doses that are less than a few tens of milli sieverts in a year. A linear extrapolation from higher dose levels should be assumed only for the purpose of applying regulatory controls. Secondly, estimates of collective dose arising from individual doses that are less than some tens of milli sieverts in a year should not be used to predict numbers of fatal cancers. Thirdly, the risk to an individual of doses significantly less than 100 micro sieverts in a year is so small, if it exists at all, that regulatory requirements to control exposure at this level are not warranted. (authors)

  16. Electromagnetic and heat transfer computations for non-ionizing radiation dosimetry.

    Science.gov (United States)

    Samaras, T; Regli, P; Kuster, N

    2000-08-01

    Reliable information on the heat distribution inside biological tissues is essential for the planning and optimization of experiments which aim to study the effects of non-ionizing radiation (NIR). In electrodynamics, the finite-difference time-domain (FDTD) technique has become the dominant technique for radiofrequency dosimetry. In order to obtain the electromagnetic field and heat distributions within the same simulation run without changing discretization, a heat diffusion solver has been directly integrated into an advanced electrodynamic FDTD kernel. The implementation enables both coupled and sequential simulations. It also includes the ability to work with complex bodies and to accelerate heat diffusion. This paper emphasizes the importance of this combination in the field of NIR dosimetry. Two examples from this area are given: the validation of dosimetry with temperature probes and the estimation of the highest thermal load during bioexperiments.

  17. Study of total ionizing dose radiation effects on enclosed gate transistors in a commercial CMOS technology

    Institute of Scientific and Technical Information of China (English)

    Li Dong-Mei; Wang Zhi-Hua; Huangfu Li-Ying; Gou Qiu-Jing

    2007-01-01

    This paper studies the total ionizing dose radiation effects on MOS (metal-oxide-semiconductor) transistors with normal and enclosed gate layout in a standard commercial CMOS (compensate MOS) bulk process. The leakage current, threshold voltage shift, and transconductance of the devices were monitored before and after γ-ray irradiation.The parameters of the devices with different layout under different bias condition during irradiation at different total dose are investigate. The results show that the enclosedosed layout not only effectively eliminates the leakage but also improves the performance of threshold voltage and transconductance for NMOS (n-type channel MOS) transistors. The experimental results also indicate that analogue bias during irradiation is the worst case for enclosed gate NMOS. There is no evident different behaviour observed between normal PMOS (p-type channel MOS) transistors and enclosed gate PMOS transistors.

  18. Modeling of characteristics of ionizing radiation detector based on AlGaAs-GaAs heterostructure

    CERN Document Server

    Ayzenshtat, G I; Tolbanov, O P; Khan, V A

    2002-01-01

    Calculations of parameters of an ionizing radiation detector on the basis of the transistor heterostructure n(AlGaAs)-p sup + (GaAs)-n sup - (GaAs) have been carried out. The parameters of the structure have been optimized to achieve a maximum amplification factor at a minimum density of a collector current. It has been shown that in dynamics, when the detector is connected as a phototransistor with the broken base, the implementation of intrinsic amplification of the signal from one X-ray photon is impossible. However, the irradiation with continuous X-ray flux allows to achieve high amplification in the structure with small sizes of the emitter.

  19. Potential role of DNA-dependent protein kinase in cellular resistance to ionizing radiation

    Institute of Scientific and Technical Information of China (English)

    LI Ning; ZHANG Hong; WANG Yanling; WANG Xiaohu; HAO Jifang

    2009-01-01

    In this paper, we study the ability of DNA-PK-deficient (M059J) and -proficient (M059K) cells to undergo the rate of cellular proliferation, cell cycle distribution and apoptosis after 10 Gy X-ray irradiation, and the role of DNA-PK in radiosensitivity. The results showed that M059J cells exhibited hyper-radiosensitivity compared with M059K cells. A strong G2 phase arrest was observed in M059J cells post irradiation. Significant accumulation in the G2 phase in M059J cells was accompanied by apoptosis at 12 h. Altogether, the data suggested that DNA-PK may have two roles in mammalian cells after DNA damage, a role in DNA DSB repair and a second role in DNA-damaged cells to traverse a G2 checkpoint, by which DNA-PK may affect cellular sensitivity to ionizing radiation.

  20. Achievements in creation of the space patrol apparatus of ionizing radiation of the Sun

    Energy Technology Data Exchange (ETDEWEB)

    Avakyan, S.V. [S.I. Vavilov State Optical Institute, Birgevaya linia, 12, Saint-Petersburg 199034 (Russian Federation); Afanas' ev, I.M. [S.I. Vavilov State Optical Institute, Birgevaya linia, 12, Saint-Petersburg 199034 (Russian Federation)]. E-mail: afanasy@pochta.ru; Kuvaldin, E.V. [S.I. Vavilov State Optical Institute, Birgevaya linia, 12, Saint-Petersburg 199034 (Russian Federation); Leonov, N.B. [S.I. Vavilov State Optical Institute, Birgevaya linia, 12, Saint-Petersburg 199034 (Russian Federation); Savushkin, A.V. [S.I. Vavilov State Optical Institute, Birgevaya linia, 12, Saint-Petersburg 199034 (Russian Federation); Serova, A.E. [S.I. Vavilov State Optical Institute, Birgevaya linia, 12, Saint-Petersburg 199034 (Russian Federation); Voronin, N.A. [S.I. Vavilov State Optical Institute, Birgevaya linia, 12, Saint-Petersburg 199034 (Russian Federation)

    2005-05-01

    The paper describes the results and achievements of our work in the creation of optical-electronic instruments for space patrol apparatus of ionizing radiation of the Sun. At present, such monitoring of the most important solar irradiance in the spectral range of 0.8-119 nm does not exist anywhere in the world because of the methodological and technical difficulties. The main difficulty was overcome only after the creation of a 'solar-blind' detector-open secondary electron multiplier (SEM), which was produced by the S.I. Vavilov State Optical Institute (SOI). Now all the space patrol instrumentation has been created and laboratory tested. The basic points of the work are presented here.

  1. [Rapid dicentric assay of human blood lymphocytes after exposure to low doses of ionizing radiation].

    Science.gov (United States)

    Repin, M V; Repina, L A

    2011-01-01

    The probability of losses of different chromosome aberrations during the dicentric chromosome assay of metaphase cells with incomplete sets of chromosome centromeres was estimated using a mathematical model for low doses of ionizing radiation. A dicentric assay of human blood lymphocytes without determination of the total amount of chromosome centromeres in cells without chromosome aberrations (rapid dicentric assay) has been proposed. The rapid dicentric analysis allows to register chromosome aberrations in full compliance with the conventional classification. The experimental data have shown no statistically significant difference between the frequencies of dicentric chromosomes detected by rapid and classical dicentric chromosome assays of human lymphocytes exposed to 0.5 Gy of 60Co gamma-rays. The rate of the rapid dicentric assay was almost twice as high as that of the classical dicentric assay.

  2. Non-ionizing radiation protection summary of research and policy options

    CERN Document Server

    Wood, Andrew W

    2017-01-01

    This book explains the characteristics of all forms of electromagnetic non-ionizing radiation (NIR) and analyzes the relationship between exposure and its biological effects, as well as the known dose-response relationships associated with each. Taking a uniquely holistic approach to the concept of health that builds upon the WHO definition to include not only absence of disease, but the physical, mental and social well-being of individuals and the population, it reviews established and potential risks and protections, along with regulatory issues associated with each. The risks to public health of NIR, whether in the form of UV light, radio waves from wireless devices, or electric and magnetic fields associated with electrical power systems, is currently a cause of great concern among members of the public and lawmakers. But in order to separate established science from speculation and make informed decisions about how to mitigate the risks of NIR and allocate precious resources, policymakers, manufacturers...

  3. 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.

  4. Genome Wide Evaluation of Normal Human Tissue in Response to Controlled, In vivo Low-Dose Low LET Ionizing Radiation Exposure: Pathways and Mechanisms Final Report, September 2013

    Energy Technology Data Exchange (ETDEWEB)

    Rocke, David M. [University of California Davis

    2013-09-09

    During course of this project, we have worked in several areas relevant to low-dose ionizing radiation. Using gene expression to measure biological response, we have examined the response of human skin exposed in-vivo to radation, human skin exposed ex-vivo to radiation, and a human-skin model exposed to radiation. We have learned a great deal about the biological response of human skin to low-dose ionizing radiation.

  5. Mitochondrial-Derived Oxidants and Cellular Responses to Low Dose/Low LET Ionizing Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Spitz, Douglas R.

    2009-11-09

    Exposure to ionizing radiation results in the immediate formation of free radicals and other reactive oxygen species (ROS). It has been assumed that the subsequent injury processes leading to genomic instability and carcinogenesis following radiation, derive from the initial oxidative damage caused by these free radicals and ROS. It is now becoming increasingly obvious that metabolic oxidation/reduction (redox) reactions can be altered by irradiation leading to persistent increases in steady-state levels of intracellular free radicals and ROS that contribute to the long term biological effects of radiation exposure by causing chronic oxidative stress. The objective during the last period of support (DE-FG02-05ER64050; 5/15/05-12/31/09) was to determine the involvement of mitochondrial genetic defects in metabolic oxidative stress and the biological effects of low dose/low LET radiation. Aim 1 was to determine if cells with mutations in succinate dehydrogenase (SDH) subunits C and D (SDHC and SDHD in mitochondrial complex II) demonstrated increases in steady-state levels of reactive oxygen species (ROS; O2•- and H2O2) as well as demonstrating increased sensitivity to low dose/low LET radiation (10 cGy) in cultured mammalian cells. Aim #2 was to determine if mitochondrially-derived ROS contributed to increased sensitivity to low dose/low LET radiation in mammalian cells containing mutations in SDH subunits. Aim #3 was to determine if a causal relationship existed between increases in mitochondrial ROS production, alterations in electron transport chain proteins, and genomic instability in the progeny of irradiated cells. Evidence gathered in the 2005-2009 period of support demonstrated that mutations in genes coding for mitochondrial electron transport chain proteins (ETC); either Succinate Dehydrogenase (SDH) subunit C (SDHC) or subunit D (SDHD); caused increased ROS production, increased genomic instability, and increased sensitivity to low dose/low LET radiation

  6. [Saccharomyces cerevisiae as a model organism for studying the carcinogenicity of non-ionizing electromagnetic fields and radiation].

    Science.gov (United States)

    Voĭchuk, S I

    2014-01-01

    Medical and biological aspects of the effects of non-ionizing electromagnetic (EM) fields and radiation on human health are the important issues that have arisen as a result of anthropogenic impact on the biosphere. Safe use of man-made sources of non-ionizing electromagnetic fields and radiation in a broad range of frequencies--static, radio-frequency and microwave--is a subject of discussions and speculations. The main problem is the lack of understanding of the mechanism(s) of reception of EMFs by living organisms. In this review we have analyzed the existing literature data regarding the effects of the electromagnetic radiation on the model eukaryotic organism--yeast Saccharomyces cerevisiae. An attempt was made to estimate the probability of induction of carcinogenesis in humans under the influence of magnetic fields and electromagnetic radiation of extremely low frequency, radio frequency and microwave ranges.

  7. Responses of human embryonic stem cells and their differentiated progeny to ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Ying; Zhang, Ningzhe; Ellerby, Lisa M.; Davalos, Albert R.; Zeng, Xianmin; Campisi, Judith [Buck Institute for Research on Aging, Novato, CA 94945 (United States); Desprez, Pierre-Yves, E-mail: pydesprez@cpmcri.org [Buck Institute for Research on Aging, Novato, CA 94945 (United States); California Pacific Medical Center, Research Institute, San Francisco, CA 94107 (United States)

    2012-09-14

    Highlights: Black-Right-Pointing-Pointer hESCs and their progeny, NSCs and neurons, were exposed to ionizing radiation. Black-Right-Pointing-Pointer Upon irradiation, most hESCs died within 5-7 h. Black-Right-Pointing-Pointer Surviving NSCs underwent senescence and displayed features of astrocytes. Black-Right-Pointing-Pointer Surviving NSCs did not display the secretory phenotype expressed by pure astrocytes. Black-Right-Pointing-Pointer This study is to better understand the stress-responses of hESCs and their progeny. -- Abstract: Human embryonic stem cells (hESCs) hold promise for the treatment of many human pathologies. For example, hESCs and the neuronal stem cells (NSCs) and neurons derived from them have significant potential as transplantation therapies for a variety of neurodegenerative diseases. Two concerns about the use of hESCs and their differentiated derivatives are their ability to function and their ability to resist neoplastic transformation in response to stresses that inevitably arise during their preparation for transplantation. To begin to understand how these cells handle genotoxic stress, we examined the responses of hESCs and derived NSCs and neurons to ionizing radiation (IR). Undifferentiated hESCs were extremely sensitive to IR, with nearly all the cells undergoing cell death within 5-7 h. NSCs and neurons were substantially more resistant to IR, with neurons showing the most resistant. Of interest, NSCs that survived IR underwent cellular senescence and acquired astrocytic characteristics. Unlike IR-treated astrocytes, however, the NSC-derived astrocytic cells that survived IR did not display the typical pro-inflammatory, pro-carcinogenic senescence-associated secretory phenotype. These findings suggest distinct genotoxic stress-responses of hESCs and derived NSC and neuronal populations, and suggest that damaged NSCs, while failing to function, may not cause local inflammation.

  8. Activation of mitogen-activated protein kinase pathway by extremely low-dose ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Keiji; Kodama, Seiji; Watanabe, Masami [Nagasaki Univ., Graduate School of Biomedical Sciences, Nagasaki (Japan)

    2003-07-01

    We demonstrated here that X-ray irradiation at very low doses of between 2 and 5 cGy stimulated activity of a member of mitogen-activated protein (MAP) kinase, the extracellular signal-regulated kinase (ERK) 1/2, in normal human diploid cells. Higher doses of irradiation at more than 1 Gy induced phosphorylation of ERK1/2 and accumulated p53 protein. Phosphorylation of ERK1/2 decreased with dose down to 50 cGy, however, doses of between 5 cGy and 2 cGy phosphorylated ERK1/2 as efficiently as higher doses of X-rays, while the p53 protein level was no longer changed by doses below 50 cGy. ATM-dependent phosphorylation of p53 protein at Ser15 and histone H2AX at Ser139 was only observed at higher doses at more than 10 cGy of X-rays. We found that MEK1 was phosphorylated with both 2 cGy and 6 Gy of X-rays, and that the MEK1 inhibitor, PD98059 decreased phosphorylation of the ERK1/2 proteins induced by 2 cGy or 6 Gy of X-rays. Similar suppressive effect was observed with the specific epidermal growth factor (EGF) receptor tyrosine kinase inhibitor, AG1478. These results indicate that a limited range of low dose ionizing radiation differentially activate ERK1/2 kinases via activation of EGF receptor and MEK, which mediates various effects of cells receiving very low doses of ionizing radiation. (author)

  9. Effects of ISS equivalent ionizing radiation dose on Human T-lymphocytes

    Science.gov (United States)

    Meloni, Maria Antonia; Pani, Giuseppe; Benotmane, Rafi; Mastroleo, Felice; Aboul-El-Ardat, Khalil; Janssen, Ann; Leysen, Liselotte; Vanhavere, Filip; Leys, Natalie; Galleri, Grazia; Pippia, Proto; Baatout, Sarah

    One of the objectives of the current international space programs is to investigate the effects of cosmic environment on Humans. It is known that during a long exposure to the space conditions, including ionizing radiations and microgravity, the immune system of the astronauts is impaired. In past years several experiments were performed to identify responsible factors of in vitro mitogenic activation process in human T-lymphocytes under simulated microgravity effect and during dedicated space missions. It come out that the lack of immune response in microgravity occurs at the cellular and molecular level. In order to evaluate effects on pure primary T-lymphocytes from peripheral blood exposed to International Space Station (ISS)-like ionizing radiation, we applied a mixture of Cesium-137, as representative of low energy particles, and Californium-252, as representative of hight energy particles, with rate similar to those monitored inside the ISS during previous space mission (Goossens et all. 2006). This facility is available at SCK•CEN (Belgium) (Mastroleo et al., 2009). Although the dose received by the cells was relatively low, flow cytometry analysis 24 hours after irradiation showed a decrease in cell viability coupled with the increase of the caspase-3 activity. However, Bcl-2 activity did not seem to be affected by the radiation. Furthermore, activation of cells induced an increase of the cell size and alteration of cellular morphology. Cell cycle as well as 8-oxo-G were also modified upon radiation and activation. Gene expression analysis shows a modulation of genes rather as a consequence of exposure than with the activation status. 330 genes have been identified to be significantly modulated in function of the time and have been grouped in four different cluster representing significant expression profiles. Preliminary functional analysis shows mainly genes involved in the immune response and inflammatory diseases as well as oxidative stress and

  10. Study of genetic effects of high energy radiations with different ionizing capacities on extracellular phages.

    Science.gov (United States)

    Bresler, S E; Kalinin, V L; Kopylova, Y U; Krivisky, A S; Rybchin, V N; Shelegedin, V N

    1975-07-01

    The inactivating and mutagenic action of high-energy radiations with different ionizing capacities (gamma-rays, protons, alpha-particles and accelerated ions of 12C and 20Ne) was studied by using coliphages lambda11 and SD as subjects. In particular the role of irradiation conditions (broth suspension, pure buffer, dry samples) and of the host functions recA, exrA and polA was investigated. The dose-response curve of induced mutagenesis was studied by measuring the yield of vir mutants in lambda11 and plaque mutants in SD. The following results were obtained. (1) The inactivation kinetics of phages under the action of gamma-rays and protons was first order to a survival of 10(-7). Heavy ions also showed exponential inactivation kinetics to a survival of 10(-4). At higher doses of 20Ne ion bombardment some deviation from one-hit kinetics was observed. For dry samples of phages the dimensions of targets for all types of radiation were approximately proportional to the molecular weights of phage DNA's. For densely ionizing radiation (heavy ions) the inactivating action was 3-5 times weaker than for gamma-rays and protons. (2) Mutagenesis was observed for all types of radiation, but heavy ions were 1-5-2 times less efficient than gamma-rays. For both phages studied the dose-response curve of mutagenesis was non-linear. The dependence on the dose was near to parabolic for lambda11. For SD a plateau or maximum of mutagenesis was observed for the relative number of mutants at a survival of about 10(-4). (3) Host-cell functions recA and exrA were practically indifferent for survival of gamma-irradiated phage lambda11, but indispensable for mutagenesis. Mutation recAI3 abolished induced vir mutations totally and exrA- reduced them significantly. The absence of the function polA had a considerable influence on phage survival, but no effect on vir mutation yield (if compared at the same survival level). (4) In conditions of indirect action of gamma-rays no vir mutations were

  11. Ionizing Radiation Stimulates Expression of Pro-Osteoclastogenic Genes in Marrow and Skeletal Tissue

    Science.gov (United States)

    Alwood, J. S.; Shahnazari, M.; Chicana, B.; Schreurs, A. S.; Kumar, A.; Bartolini, A.; Shirazi-Fard, Y.; Globus, R. K.

    2015-01-01

    Exposure to ionizing radiation can cause rapid mineral loss and increase bone-resorbing osteoclasts within metabolically-active, cancellous-bone tissue leading to structural deficits. To better understand mechanisms involved in rapid, radiation-induced bone loss, we determined the influence of total-body irradiation on expression of select cytokines known both to stimulate osteoclastogenesis and contribute to inflammatory bone disease. Adult (16wk), male C57BL/6J mice were exposed to either 2Gy gamma rays (137Cs, 0.8Gy/min) or heavy ions (56Fe, 600MeV, 0.50-1.1Gy/min); this dose corresponds to either a single fraction of radiotherapy (typical total dose is =10Gy) or accumulates over long-duration, interplanetary missions. Serum, marrow, and mineralized tissue were harvested 4hrs-7d later. Gamma irradiation caused a prompt (2.6-fold within 4hrs) and persistent (peaking at 4.1-fold within 1d) rise in the expression of the obligate osteoclastogenic cytokine, receptor activator of nuclear factor kappaB-ligand (Rankl) within marrow cells over controls. Similarly, Rankl expression peaked in marrow cells within 3d of iron exposure (9.2-fold). Changes in Rankl expression induced by gamma irradiation preceded and overlapped with a rise in expression of other pro-osteoclastic cytokines in marrow (e.g., monocyte chemotactic protein-1 increased 11.9-fold, tumor necrosis factor-alpha increased 1.7- fold over controls). Marrow expression of the RANKL decoy receptor, osteoprotegerin (Opg), also rose after irradiation (11.3-fold). The ratio Rankl/Opg in marrow was increased 1.8-fold, a net pro-resorption balance. As expected, radiation increased a serum marker of resorption (tartrate resistant acid phosphatase) and led to cancellous bone loss (16% decrease in bone volume/total volume) through reduced trabecular struts. We conclude that total-body irradiation (gamma or heavy-ion) caused temporal, concerted regulation of gene expression within marrow and mineralized tissue for

  12. 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.

  13. Essential astrophysics

    CERN Document Server

    Lang, Kenneth R

    2013-01-01

    Essential Astrophysics is a book to learn or teach from, as well as a fundamental reference volume for anyone interested in astronomy and astrophysics. It presents astrophysics from basic principles without requiring any previous study of astronomy or astrophysics. It serves as a comprehensive introductory text, which takes the student through the field of astrophysics in lecture-sized chapters of basic physical principles applied to the cosmos. This one-semester overview will be enjoyed by undergraduate students with an interest in the physical sciences, such as astronomy, chemistry, engineering or physics, as well as by any curious student interested in learning about our celestial science. The mathematics required for understanding the text is on the level of simple algebra, for that is all that is needed to describe the fundamental principles. The text is of sufficient breadth and depth to prepare the interested student for more advanced specialized courses in the future. Astronomical examples are provide...

  14. Influence of Ionizing Radiation on Stromal-Epithelial Communication in Esophageal Carcinogenesis

    Science.gov (United States)

    Huff, Janice; Patel, Zarana; Grugan, Katharine; Rustgi, Anil; Cucinotta, Francis A.

    Esophageal cancer is the 6th leading cause of cancer death worldwide and is associated with a variety of risk factors including tobacco use, heavy alcohol consumption, human papilloma virus infection, and certain dietary factors such as trace mineral and vitamin deficiencies. A connection with ionizing radiation exposure is revealed by the high excess relative risk for esophageal squamous cell carcinoma observed in the survivors of the atomic bomb detonations in Japan. Esophageal carcinomas are also seen as secondary malignancies in patients who received radiotherapy for breast and thoracic cancers; additionally, patients with head/neck and oral squamous cell cancers are at increased risk for metachronous esophageal squamous cell cancers. This malignancy is rapidly fatal, mainly because it remains asymptomatic until late, advanced stages when the disease is rarely responsive to treatment. In normal epithelium, the stromal microenvironment is essential for the maintenance and modulation of cell growth and differentiation. Cross talk between the epithelial and stromal compartments can influence many aspects of malignant progression, including tumor cell proliferation, migration, invasion and recruitment of new blood vessels. To test the hypothesis that radiation exposure plays a role in esophageal carcinogenesis via non-targeted mechanisms involving stromal-epithelial cell communication, we are studying radiation effects on hTERT-immortalized human esophageal epithelial cells and genetic variants grown in co-culture with human esophageal stromal fibrob-lasts (Okawa et al., Genes Dev. 2007. 21: 2788-2803). We examined how irradiation of stromal fibroblasts affected epithelial migration and invasion, behaviors associated with cancer promotion and progression. These assays were conducted in modified Boyden chambers using conditioned media from irradiated fibroblasts. Our results using low LET gamma radiation showed a dose-dependent increase in migration of epithelial

  15. Ionizing radiations management in university, medical and industrial media; La gestion des sources ionisantes en milieux universitaire, medical et industriel

    Energy Technology Data Exchange (ETDEWEB)

    Klein, D. [Universite Technologique de Belfort Montbeliard - LERMPS, 90 - Belfort (France)]|[Universite de Franche Comte, CREST-IRMA, 25 - Montbeliard (France)

    2001-07-01

    The radioactive sources are useful in several areas: medicine, research, measurement laboratories. Severe accidents in the past (Forbach in France 1991, Arequipa, Peru 1999, Goiania, Brazil 1987) remind us of the dangerous character of ionizing radiations. That is why the the management of radioactive sources are so regulated. Radiation protection and legal aspects of sealed and unsealed sources management are evoked, as well as the different official organisms that take a part in their management. (N.C.)

  16. The Connection Between Reddening, Gas Covering Fraction, and the Escape of Ionizing Radiation at High Redshift

    Science.gov (United States)

    Reddy, Naveen A.; Steidel, Charles C.; Pettini, Max; Bogosavljević, Milan; Shapley, Alice E.

    2016-09-01

    Using a large sample of spectroscopically confirmed z∼ 3 galaxies, we establish an empirical relationship between reddening (E(B-V)), neutral gas covering fraction ({f}{{cov}}({{H}} {{I}})), and the escape of ionizing (Lyman continuum, LyC) photons. Our sample includes 933 galaxies at z∼ 3,121 of which have deep spectroscopic observations (≳ 7 hr) at 850≲ {λ }{{rest}}≲ 1300 Å with the Low Resolution Imaging Spectrograph on Keck. The high covering fraction of outflowing optically thick {{H}} {{I}} indicated by the composite spectra of these galaxies implies that photoelectric absorption, rather than dust attenuation, dominates the depletion of LyC photons. By modeling the composite spectra as the combination of an unattenuated stellar spectrum including nebular continuum emission with one that is absorbed by {{H}} {{I}} and reddened by a line-of-sight extinction, we derive an empirical relationship between E(B-V) and {f}{{cov}}({{H}} {{I}}). Galaxies with redder UV continua have larger covering fractions of {{H}} {{I}} characterized by higher line-of-sight extinctions. We develop a model which connects the ionizing escape fraction with E(B-V), and which may be used to estimate the ionizing escape fraction for an ensemble of galaxies. Alternatively, direct measurements of the escape fraction for our sample allow us to constrain the intrinsic LyC-to-UV flux density ratio to be }{{int}}≳ 0.20, a value that favors stellar population models that include weaker stellar winds, a flatter initial mass function, and/or binary evolution. Last, we demonstrate how the framework discussed here may be used to assess the pathways by which ionizing radiation escapes from high-redshift galaxies. Based on data obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA, and was made possible by the generous financial support of the W.M. Keck Foundation.

  17. Low Dose of Ionizing Radiation Effect on the Professionally Exposure Worker

    Energy Technology Data Exchange (ETDEWEB)

    Spasojevic, V.; Joksic, T. G.; Pavelkic, V.

    2004-07-01

    This paper shows the comparative medical results of the peripheral blood hematological biochemical analysis as well as chromosome aberration in the lymphocytes of the peripheral blood of the people professionally exposed to the small doses of the ionizing radiation.Selected group is formed of 54 x-rays radiotherapy technicians (22 male and 32 female) and 38 radio-diagnosis technicians (20 male, 18 female). The ophthalmology and occupational medical specialists medically examined them. The changes on eye-lenses such as cataract have not been confirmed in any of the examined group. In regard to the TLD-dosimeter's results, there were no oversteps in the allowed annual doses. The middle value of the exposed work experience (EWE) at x-ray radiotherapy technicians was 13 years and radio-diagnosis technician a 10 years. The middle value of the red blood cells (RBC) was 4.74? 1012/1 at radiodiagnosis and 4.93? 1012/1 at radio therapist while the middle values of hemoglobin (Hgb) were 13.91 g/l and 14.3 g/l respectively. The middle value of white blood cells (WBC) at a radiotherapy technician was 6.96 ? 1091 (granulocyte 66.34% and lymphocyte 27.39%), at radiodiagnosis technician 6.92? 109/l (granulocyte 63.94% and lymphocyte 28.17%). Analysis confirmed hematological biochemical changes at 4 radio diagnostics technicians (2 anemia, leucopenia and leucocytosis). the chromosome confirmed aberration analysis in white blood cells of peripheral blood that 16 technicians do have the changes of the dicenteric type and acentric fragment up to 14 technicians of the radio-diagnosis and at 2 radiotherapy technicians. At 3 radio diagnostic technician found lowered value of leukocytes followed by the changes of dicentric type of chromosomes but the results of one person showed that the while blood cells were essentially raised level 11.6? 109/l followed as well as with the changes on the chromosomes. All the examined workers that showed positive to any changes were subjectively

  18. Unraveling the global microRNAome responses to ionizing radiation in human embryonic stem cells.

    Directory of Open Access Journals (Sweden)

    Mykyta V Sokolov

    Full Text Available MicroRNAs (miRNA comprise a group of short ribonucleic acid molecules implicated in regulation of key biological processes and functions at the post-transcriptional level. Ionizing radiation (IR causes DNA damage and generally triggers cellular stress response. However, the role of miRNAs in IR-induced response in human embryonic stem cells (hESC has not been defined yet. Here, by using system biology approaches, we show for the first time, that miRNAome undergoes global alterations in hESC (H1 and H9 lines after IR. Interrogation of expression levels of 1,090 miRNA species in irradiated hESC showed statistically significant changes in 54 genes following 1 Gy of X-ray exposures; global miRNAome alterations were found to be highly temporally and cell line--dependent in hESC. Time-course studies showed that the 16 hr miRNAome radiation response of hESC is much more robust compared to 2 hr-response signature (only eight genes, and may be involved in regulating the cell cycle. Quantitative real-time PCR performed on some miRNA species confirms the robustness of our miRNA microarray platform. Positive regulation of differentiation-, cell cycle-, ion transport- and endomembrane system-related processes were predicted to be negatively affected by miRNAome changes in irradiated hESC. Our findings reveal a fundamental role of miRNAome in modulating the radiation response, and identify novel molecular targets of radiation in hESC.

  19. Analytic Shielding Optimization to Reduce Crew Exposure to Ionizing Radiation Inside Space Vehicles

    Science.gov (United States)

    Gaza, Razvan; Cooper, Tim P.; Hanzo, Arthur; Hussein, Hesham; Jarvis, Kandy S.; Kimble, Ryan; Lee, Kerry T.; Patel, Chirag; Reddell, Brandon D.; Stoffle, Nicholas; Zapp, E. Neal; Shelfer, Tad D.

    2009-01-01

    A sustainable lunar architecture provides capabilities for leveraging out-of-service components for alternate uses. Discarded architecture elements may be used to provide ionizing radiation shielding to the crew habitat in case of a Solar Particle Event. The specific location relative to the vehicle where the additional shielding mass is placed, as corroborated with particularities of the vehicle design, has a large influence on protection gain. This effect is caused by the exponential- like decrease of radiation exposure with shielding mass thickness, which in turn determines that the most benefit from a given amount of shielding mass is obtained by placing it so that it preferentially augments protection in under-shielded areas of the vehicle exposed to the radiation environment. A novel analytic technique to derive an optimal shielding configuration was developed by Lockheed Martin during Design Analysis Cycle 3 (DAC-3) of the Orion Crew Exploration Vehicle (CEV). [1] Based on a detailed Computer Aided Design (CAD) model of the vehicle including a specific crew positioning scenario, a set of under-shielded vehicle regions can be identified as candidates for placement of additional shielding. Analytic tools are available to allow capturing an idealized supplemental shielding distribution in the CAD environment, which in turn is used as a reference for deriving a realistic shielding configuration from available vehicle components. While the analysis referenced in this communication applies particularly to the Orion vehicle, the general method can be applied to a large range of space exploration vehicles, including but not limited to lunar and Mars architecture components. In addition, the method can be immediately applied for optimization of radiation shielding provided to sensitive electronic components.

  20. MDP: A Deinococcus Mn2+-Decapeptide Complex Protects Mice from Ionizing Radiation.

    Science.gov (United States)

    Gupta, Paridhi; Gayen, Manoshi; Smith, Joan T; Gaidamakova, Elena K; Matrosova, Vera Y; Grichenko, Olga; Knollmann-Ritschel, Barbara; Daly, Michael J; Kiang, Juliann G; Maheshwari, Radha K

    2016-01-01

    The radioprotective capacity of a rationally-designed Mn2+-decapeptide complex (MDP), based on Mn antioxidants in the bacterium Deinococcus radiodurans, was investigated in a mouse model of radiation injury. MDP was previously reported to be extraordinarily radioprotective of proteins in the setting of vaccine development. The peptide-component (DEHGTAVMLK) of MDP applied here was selected from a group of synthetic peptides screened in vitro for their ability to protect cultured human cells and purified enzymes from extreme damage caused by ionizing radiation (IR). We show that the peptides accumulated in Jurkat T-cells and protected them from 100 Gy. MDP preserved the activity of T4 DNA ligase exposed to 60,000 Gy. In vivo, MDP was nontoxic and protected B6D2F1/J (female) mice from acute radiation syndrome. All irradiated mice treated with MDP survived exposure to 9.5 Gy (LD70/30) in comparison to the untreated mice, which displayed 63% lethality after 30 days. Our results show that MDP provides early protection of white blood cells, and attenuates IR-induced damage to bone marrow and hematopoietic stem cells via G-CSF and GM-CSF modulation. Moreover, MDP mediated the immunomodulation of several cytokine concentrations in serum including G-CSF, GM-CSF, IL-3 and IL-10 during early recovery. Our results present the necessary prelude for future efforts towards clinical application of MDP as a promising IR countermeasure. Further investigation of MDP as a pre-exposure prophylactic and post-exposure therapeutic in radiotherapy and radiation emergencies is warranted.

  1. Line-driven Disk Winds in Active Galactic Nuclei: The Critical Importance of Ionization and Radiative Transfer

    CERN Document Server

    Higginbottom, Nick; Knigge, Christian; Long, Knox S; Matthews, James H; Sim, Stuart A

    2014-01-01

    Accretion disk winds are thought to produce many of the characteristic features seen in the spectra of active galactic nuclei (AGN) and quasi-stellar objects (QSOs). These outflows also represent a natural form of feedback between the central supermassive black hole and its host galaxy. The mechanism for driving this mass loss remains unknown, although radiation pressure mediated by spectral lines is a leading candidate. Here, we calculate the ionization state of, and emergent spectra for, the hydrodynamic simulation of a line-driven disk wind previously presented by Proga & Kallman (2004). To achieve this, we carry out a comprehensive Monte Carlo simulation of the radiative transfer through, and energy exchange within, the predicted outflow. We find that the wind is much more ionized than originally estimated. This is because it is much more difficult to shield any wind regions effectively when the outflow itself is allowed to reprocess and redirect ionizing photons. As a result, the wind no longer produ...

  2. Candidate gene biodosimeters of mice and human exposure to ionizing radiation by quantitative reverse transcription polymerase chain reaction

    Directory of Open Access Journals (Sweden)

    Hamed Rezaeejam

    2015-01-01

    Full Text Available Understanding of cellular responses to ionizing radiation (IR is essential for the development of predictive markers useful for assessing human exposure. Biological markers of exposure to IR in human populations are of great interest for assessing normal tissue injury in radiation oncology and for biodosimetry in nuclear incidents and accidental radiation exposures. Traditional radiation exposure biomarkers based on cytogenetic assays (biodosimetry, are time-consuming and do not provide results fast enough and requires highly trained personnel for scoring. Hence, the development of rapid biodosimetry methods is one of the highest priorities. Exposure of cells to IR activates multiple signal transduction pathways, which result in complex alterations in gene-expression. Real-time quantitative reverse transcription-polymerase chain reaction (RT-qPCR has become the benchmark for the detection and quantification of RNA targets and is being utilized increasingly in monitoring the specific genes with more accurately and sensitively. This review evaluates the RT-qPCR as a biodosimetry method and we investigated the papers from 2000 up to now, which identified the genes-expression related the DNA repair, cell cycle checkpoint, and apoptosis induced by ionization radiation in peripheral blood and determined as biodosimeters. In conclusion, it could be say that RT-qPCR technique for determining the specific genes as biodosimeters could be a fully quantitative reliable and sensitive method. Furthermore, the results of the current review will help the researchers to recognize the most expressed genes induced by ionization radiation.

  3. Secondary calibration laboratory for ionizing radiation laboratory accreitation program National Institute of Standards and Technology National Voluntary Laboratory Accreditation Program

    Energy Technology Data Exchange (ETDEWEB)

    Martin, P.R.

    1993-12-31

    This paper presents an overview of the procedures and requirements for accreditation under the Secondary Calibration Laboratory for Ionizing Radiation Program (SCLIR LAP). The requirements for a quality system, proficiency testing and the onsite assessment are discussed. The purpose of the accreditation program is to establish a network of secondary calibration laboratories that can provide calibrations traceable to the primary national standards.

  4. Ionizing radiation and lipid peroxidation in human body; Radiazioni ionizzanti e perossidazione lipidica nell`organismo umano

    Energy Technology Data Exchange (ETDEWEB)

    Giubileo, Gianfranco [ENEA, Centro Ricerche Frascati, Roma (Italy)

    1997-07-01

    Lipids are organic compounds constituting the living cells. Lipid molecules can be disassembled through peroxidative pathways and hydrocarbons can be bred as end-product of lipid peroxidation in vivo. Lipid peroxidation can be started by an indirect effect of ionizing radiation. So a radioinduced cellular damage in human body can be detected by monitoring the production of specific hydrocarbons.

  5. Cell cycle phase dependent role of DNA polymerase beta in DNA repair and survival after ionizing radiation.

    NARCIS (Netherlands)

    Vermeulen, C.; Verwijs-Janssen, M.; Begg, A.C.; Vens, C.

    2008-01-01

    PURPOSE: The purpose of the present study was to determine the role of DNA polymerase beta in repair and response after ionizing radiation in different phases of the cell cycle. METHODS AND MATERIALS: Synchronized cells deficient and proficient in DNA polymerase beta were irradiated in different pha

  6. Did high energy astrophysical sources contribute to Martian atmospheric loss?

    CERN Document Server

    Atri, Dimitra

    2016-01-01

    Mars is believed to have had a substantial atmosphere in the past. Atmospheric loss led to depressurization and cooling, and is thought to be the primary driving force responsible for the loss of liquid water from its surface. Recently, MAVEN observations have provided new insight into the physics of atmospheric loss induced by ICMEs and solar wind interacting with the Martian atmosphere. In addition to solar radiation, it is likely that its atmosphere has been exposed to radiation bursts from high-energy astrophysical sources which become highly probable on timescales of ~Gy and beyond. These sources are capable of significantly enhancing the rates of photoionization and charged particle-induced ionization in the upper atmosphere. Here, we explore the possibility of damage from Galactic Gamma Ray Bursts, nearby supernovae, encounter with dense interstellar clouds and extreme solar events. We use Monte Carlo simulations to model the interaction of charged particles and photons from astrophysical sources in th...

  7. Characterization and evaluation of ionizing and non-ionizing imaging systems used in state of the art image-guided radiation therapy techniques

    Science.gov (United States)

    Stanley, Dennis Nichols

    With the growing incidence of cancer worldwide, the need for effective cancer treatment is paramount. Currently, radiation therapy exists as one of the few effective, non-invasive methods of reducing tumor size and has the capability for the elimination of localized tumors. Radiation therapy utilizes non-invasive external radiation to treat localized cancers but to be effective, physicians must be able to visualize and monitor the internal anatomy and target displacements. Image-Guided Radiation Therapy frequently utilizes planar and volumetric imaging during a course of radiation therapy to improve the precision and accuracy of the delivered treatment to the internal anatomy. Clinically, visualization of the internal anatomy allows physicians to refine the treatment to include as little healthy tissue as possible. This not only increases the effectiveness of treatment by damaging only the tumor but also increases the quality of life for the patient by decreasing the amount of healthy tissue damaged. Image-Guided Radiation Therapy is commonly used to treat tumors in areas of the body that are prone to movement, such as the lungs, liver, and prostate, as well as tumors located close to critical organs and tissues such as the tumors in the brain and spinal cord. Image-Guided Radiation Therapy can utilize both ionizing modalities, like x-ray based planar radiography and cone-beam CT, and nonionizing modalities like MRI, ultrasound and video-based optical scanning systems. Currently ionizing modalities are most commonly utilized for their ability to visualize and monitor internal anatomy but cause an increase to the total dose to the patient. Nonionizing imaging modalities allow frequent/continuous imaging without the increase in dose; however, they are just beginning to be clinically implemented in radiation oncology. With the growing prevalence and variety of Image-Guided Radiation Therapy imaging modalities the ability to evaluate the overall image quality, monitor

  8. Effect of ionizing (gamma and non-ionizing (UV radiation on the development of Trichogramma euproctidis (Hymenoptera: Trichogrammatidae

    Directory of Open Access Journals (Sweden)

    Tuncbilek Aydin S.

    2012-01-01

    Full Text Available The potential of using gamma and ultraviolet radiation as an alternative treatment to increase the efficiency of Trichogramma euproctidis (Girault 1911 (Hymenoptera: Trichogrammatidae was investigated in the laboratory. The developmental and adult stages of T. euproctidis were exposed to gamma radiation of different doses (0-30 Gy and ultraviolet radiation of 254 nm wavelengths (UV-C for different durations (0-10 min to assess their effect on each of the instars and their potential in breaking the developmental cycle of the egg parasitoid. The LD50 values for eggs, prepupae, pupae and adults were 8.1, 10.0, 22.7 and 9.5 Gy for gamma radiation and 9.5, 0.12, 2.0 and 11.9 min for UV radiation, respectively. The pupa and adult stages were more radioresistant to both gamma and UV radiation. The most interesting and unexpected result obtained for the prepupal stage was that UV radiation has a greater effect on prepupal stages than gamma radiation.

  9. Exposure to non-ionizing electromagnetic radiation from mobile telephony and the association with psychiatric symptoms.

    Science.gov (United States)

    Silva, Denize Francisca da; Barros, Warley Rocha; Almeida, Maria da Conceição Chagas de; Rêgo, Marco Antônio Vasconcelos

    2015-10-01

    The aim of this study was to investigate the association between exposure to non-ionizing electromagnetic radiation from mobile phone base stations and psychiatric symptoms. In a cross-sectional study in Salvador, Bahia State, Brazil, 440 individuals were interviewed. Psychiatric complaints and diagnoses were the dependent variables and distance from the individual's residence to the base station was considered the main independent variable. Hierarchical logistic regression analysis was conducted to assess confounding. An association was observed between psychiatric symptoms and residential proximity to the base station and different forms of mobile phone use (making calls with weak signal coverage, keeping the mobile phone close to the body, having two or more chips, and never turning off the phone while sleeping), and with the use of other electronic devices. The study concluded that exposure to electromagnetic radiation from mobile phone base stations and other electronic devices was associated with psychiatric symptoms, independently of gender, schooling, and smoking status. The adoption of precautionary measures to reduce such exposure is recommended.

  10. Genetic variation in resistance to ionizing radiation. Final report, January 1, 1990--December 31, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Ayala, F.J.

    1992-12-31

    Results of an investigation of the gene coding for Cu, Zn superoxide dismutase (Sod) in Drosophila melanogaster seeking to understand the enzyme`s role in cell protection against ionizing radiation are reported. Components of the investigation include molecular characterization of the gene; measuring the response of different genotypes to increasing levels of radiation; and investigation of the processes that maintain the Sod polymorphism in populations. While two alleles, S and F, are commonly found at the Sod locus in natural populations of D. melanogaster we have isolated from a natural population a null (CA1) mutant that yields only 3.5% of normal SOD activity. The S, F, and CA1 alleles provide a model system to investigate SOD-dependent radioresistance, because each allele yields different levels of SOD, so that S > F >> CAl. The radioprotective effects of SOD can be established by showing protective effects for the various genotypes that correspond to those inequalities. Because the allele variants studied are derived from natural populations, the proposed investigation avoids problems that arise when mutants obtained my mutagenesis are used. Moreover, each allele is studied in multiple genetic backgrounds, so that we correct for effects attributable to other loci by randomizing these effects.

  11. Effect of Exposure to Non-ionizing Radiation (Electromagnetic Fields on Human System: A Literature Review

    Directory of Open Access Journals (Sweden)

    Paula Rubya Souza C and acirc;mara

    2014-08-01

    Full Text Available The indiscriminate presence of radio base stations, which emit non-ionizing radiation (NIR, as well as the frequent use of mobile phones, can cause increased susceptibility of populations to the emergence of diseases such as cancers of the head and neck, biochemical, hematopoietic and hepatic changes, among others. Exposure to physical contamination, including NIR, has been implicated in numerous diseases, raising concerns about the widespread sources of exposure to this type of radiation. This paper reviews studies that have assessed associations between likely exposure to electromagnetic fields, such as radiofrequency transmissions, and many kinds of human diseases including cancer, as well as alerts to the current knowledge on the association between environmental exposure to NIR and the risk of development of adverse human health effects. This way, there appears to be an urgent need to reconsider exposure limits for low frequency and static magnetic fields, based on combined experimental and epidemiological research. [J Interdiscipl Histopathol 2014; 2(4.000: 187-190

  12. Comparison of free radicals formation induced by cold atmospheric plasma, ultrasound, and ionizing radiation.

    Science.gov (United States)

    Rehman, Mati Ur; Jawaid, Paras; Uchiyama, Hidefumi; Kondo, Takashi

    2016-09-01

    Plasma medicine is increasingly recognized interdisciplinary field combining engineering, physics, biochemistry and life sciences. Plasma is classified into two categories based on the temperature applied, namely "thermal" and "non-thermal" (i.e., cold atmospheric plasma). Non-thermal or cold atmospheric plasma (CAP) is produced by applying high voltage electric field at low pressures and power. The chemical effects of cold atmospheric plasma in aqueous solution are attributed to high voltage discharge and gas flow, which is transported rapidly on the liquid surface. The argon-cold atmospheric plasma (Ar-CAP) induces efficient reactive oxygen species (ROS) in aqueous solutions without thermal decomposition. Their formation has been confirmed by electron paramagnetic resonance (EPR) spin trapping, which is reviewed here. The similarities and differences between the plasma chemistry, sonochemistry, and radiation chemistry are explained. Further, the evidence for free radical formation in the liquid phase and their role in the biological effects induced by cold atmospheric plasma, ultrasound and ionizing radiation are discussed.

  13. Process for crosslinking methylene-containing aromatic polymers with ionizing radiation

    Science.gov (United States)

    Bell, Vernon L. (Inventor); Havens, Stephen J. (Inventor)

    1990-01-01

    A process for crosslinking aromatic polymers containing radiation-sensitive methylene groups (-CH2-) by exposing the polymers to ionizing radiation thereby causing crosslinking of the polymers through the methylene groups is described. Crosslinked polymers are resistant to most organic solvents such as acetone, alcohols, hydrocarbons, methylene, chloride, chloroform, and other halogenated hydrocarbons, to common fuels and to hydraulic fluids in contrast to readily soluble uncrosslinked polymers. In addition, the degree of crosslinking of the polymers depends upon the percentage of the connecting groups which are methylene which ranges from 5 to 50 pct and preferably from 25 to 50 pct of the connecting groups, and is also controlled by the level of irradiation which ranges from 25 to 1000 Mrads and preferably from 25 to 250 Mrads. The temperature of the reaction conditions ranges from 25 to 200 C and preferably at or slightly above the glass transition temperature of the polymer. The crosslinked polymers are generally more resistant to degradation at elevated temperatures such as greater than 150 C, have a reduced tendency to creep under load, and show no significant embrittlement of parts fabricated from the polymers.

  14. Effects of ionizing radiation on the physicochemical properties of red wine Cabernet Sauvignon

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Fellipe S.; Santos, Anderson R.L.; Pereira, Walsan W., E-mail: fellipess@ird.gov.br, E-mail: aleiras@ird.gov.br, E-mail: walsan@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    Oenology has as its main purpose the continuous improvement of wine quality without jeopardizing its proprieties, and the intent is to make these improvements using innovative new technologies. The objective of the present work is to assess the effect of ionizing radiation on the physicochemical properties of Cabernet Sauvignon that may lead to changes in wine quality, aging process and other related characteristics. The samples used for this process were irradiated using an Argonaut reactor powered at 340 Watts and with a thermal neutron fluency of 10{sup 9} n.cm{sup -2}.s{sup -1}. For irradiation experiments, the samples were put into the reactor chamber until the reactor reached criticality and for an additional 30 minutes while receiving radiation. The analyzed data included density, alcoholic, ashes and spectrophotometric measurements of absorbance at wavelengths of 420, 520 and 620 nm. Increased absorbance values at 420 nm indicate an increase in tannin composition of the wine and therefore a higher level of oxidation. Intriguingly, a rise in absorbance was also observed at 520 nm for the same test samples; which is inconsistent with published data on irradiated cachaca that showed that anthocyanin levels dropped at 520 nm after irradiation. In summary, for measurements made at a fluency of 109 n/cm{sup 2}.s for 30 min, the effects were minimal, which requires a higher dose to have better effects. Future studies should evaluating dosing effects of irradiation on improving the quality of the Cabernet Sauvignon. (author)

  15. Multinucleated Giant Cancer Cells Produced in Response to Ionizing Radiation Retain Viability and Replicate Their Genome

    Science.gov (United States)

    Mirzayans, Razmik; Andrais, Bonnie; Scott, April; Wang, Ying W.; Kumar, Piyush; Murray, David

    2017-01-01

    Loss of wild-type p53 function is widely accepted to be permissive for the development of multinucleated giant cells. However, whether therapy-induced multinucleation is associated with cancer cell death or survival remains controversial. Herein, we demonstrate that exposure of p53-deficient or p21WAF1 (p21)-deficient solid tumor-derived cell lines to ionizing radiation (between 2 and 8 Gy) results in the development of multinucleated giant cells that remain adherent to the culture dish for long times post-irradiation. Somewhat surprisingly, single-cell observations revealed that virtually all multinucleated giant cells that remain adherent for the duration of the experiments (up to three weeks post-irradiation) retain viability and metabolize 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT), and the majority (>60%) exhibit DNA synthesis. We further report that treatment of multinucleated giant cells with pharmacological activators of apoptosis (e.g., sodium salicylate) triggers their demise. Our observations reinforce the notion that radiation-induced multinucleation may reflect a survival mechanism for p53/p21-deficient cancer cells. With respect to evaluating radiosensitivity, our observations underscore the importance of single-cell experimental approaches (e.g., single-cell MTT) as the creation of viable multinucleated giant cells complicates the interpretation of the experimental data obtained by commonly-used multi-well plate colorimetric assays. PMID:28208747

  16. Transient effects of ionizing and displacive radiation on the dielectric properties of ceramics

    Science.gov (United States)

    Goulding, R. H.; Zinkle, S. J.; Rasmussen, D. A.; Stoller, R. E.

    1996-03-01

    A resonant cavity technique was used to measure the dielectric constant and loss tangent of ceramic insulators at a frequency near 100 MHz during pulsed fission reactor irradiation near room temperature. Tests were performed on single crystal and several different grades of polycrystalline Al2O3, MgAl2O4, AlN, and Si3N4. Lead shielding experiments were performed for some of the irradiations in order to examine the importance of gamma ray versus neutron irradiation effects. With the exception of AlN, the dielectric constant of all of the ceramics decreased slightly (radiation fields of 4.2×104 Gy/s and 2.4×10-6 dpa/s, respectively. The loss tangent measured during irradiation for the different ceramics did not show any correlation with the preirradiation or postirradiation values. Analysis of the results indicates that the transient increases in loss tangent are due to radiation induced increases in the electrical conductivity. The loss tangent increases were proportional to the ionizing dose rate in all materials except for AlN, which exhibited a dose rate exponent of ˜1.6.

  17. The role of ER stress response on ionizing radiation-induced apoptosis in intestinal epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Sang; Kim, Kwang Seok; Woo, Sang Keun; Lee, Yong Jin; Jeong, Jae Hoon; Lee, Yoon Jin; Kang, Seong Man; Lim, Young Bin [Laboratory of Radiation Effect, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2014-04-15

    Apoptosis in the intestinal epithelium is the primary pathologic factor that initiates radiation-induced intestinal injury. However, mechanism involved in ionizing radiation (IR)-induced apoptosis in the intestinal epithelium is not clearly understood. The endoplasmic reticulum (ER) stress is triggered by perturbation of the ER functions, leading to the activation of the unfolded protein response (UPR), an adaptive signaling cascade aimed at restoring ER homeostasis by facilitating the degradation of misfolded proteins and expanding the protein folding capacity of the cell. Recently, IR has also been shown to induce ER stress, thereby activating the UPR signaling pathway in intestinal epithelial cells. In this study, we report the role of ER stress responses in IR-induced intestinal epithelial cell death. We show that chemical ER stress inducers, such as tunicamycin or thapsigargin, enhance IR-induced caspase3 activation. Knockdown of xbp1 or atf6 with siRNA leads to inhibition of IR-induced caspase3 activation. Taken together, our results suggest a pro-apoptotic role of ER stress in IR-exposed intestinal epithelial cells. Our findings could contribute to the development of new strategies based on modulating ER stress responses to prevent IR-induced intestinal injury.

  18. On the biophysical interpretation of lethal DNA lesions induced by ionizing radiation

    CERN Document Server

    Kundrát, P; Kundr\\'{a}t, Pavel; Stewart, Robert D.

    2005-01-01

    Although DNA damage is widely viewed as a critical target for the induction of cell killing by ionizing radiation, the exact nature of DNA damage responsible for these effects is unknown. To address this issue, the probability of forming lethal damage by single proton tracks, derived from published survival data for Chinese hamster V79 cells irradiated by protons with energies from 0.57 to 5.01 MeV, has been compared to estimated yields of complex DNA double-strand breaks (DSBs) calculated by Monte Carlo models. The reported studies indicate that total DSB yields and the yields of other classes of clustered DNA damage do not correlate well with trends in the expected number of lethal events for protons with increasing linear energy transfer (LET). However, a good correlation was found between the number of lethal events and the yields of DSBs consisting of 8 or more elementary DNA lesions. These results indicate that differences in the relative biological effectiveness (RBE) of radiations of diverse quality c...

  19. 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.

  20. Effect of High Dose Natural Ionizing Radiation on the Immune System of the Exposed Residents of Ramsar Town, Iran

    Directory of Open Access Journals (Sweden)

    Massoud Attar

    2007-06-01

    Full Text Available Iran is one of several countries that has regions of high dose natural ionizing radiation. Two wellknownvillages in the suburb of Ramsar Town in the Caspian Sea strip, Taleshmahaleh and Chaparsar,have background radiation that is 13 times higher than normal. This radiation is the result of Radium 226 and Radon gas both of which are highly water soluble.While people living in these regions do not suffer from any major health problems, we decided tostudy the their immune responses to infection and inflammation in order to determine if their habitat affects their immune defense mechanisms as a way of compensating for their exposure to high dose environmental ionizing radiation.Our results showed that the total serum antioxidant level in the exposed people was significantlylower than the individuals not exposed to high dose natural ionizing radiation. The exposedindividuals also had higher lymphocyte-induced IL-4 and IL-10 production, and lower IL-2 and IFN-γ production. In addition, neutrophil NBT, phagocytosis, and locomotion were higher in the exposed group. In contrast, lymphocyte proliferation in response to PHA was unaffected.We conclude that the immune system of individuals exposed to high dose ionizing radiation hasadapted to its environment by shifting from a Type 1 to a Type 2 response to promote antiinflammation.This may be because inflammatory Type 1 responses generate more free radicals thanType 2 responses, in addition to the free radicals generated as a result of high environmental radiation.Thus, the serum total antioxidant level in the exposed residents was lower than the unexposed group.

  1. Appearance of pseudo-Pelger Huet anomaly after accidental exposure to ionizing radiation in vivo.

    Science.gov (United States)

    Goans, Ronald E; Iddins, Carol J; Christensen, Doran; Wiley, Albert; Dainiak, Nicholas

    2015-03-01

    To evaluate the morphology of formed elements of human blood after exposure to ionizing radiation in vivo, archival smears of peripheral blood from eight individuals involved in the 1958 Y-12 criticality accident at Oak Ridge, Tennessee, were examined manually by light microscopy. For each case, increased interlobar bridging was observed in nuclei of the myeloid cells, many of which were bilobed and morphologically similar to Pelger Huet (PH) cells. The high-dose group (n = 5, 2.98-4.61 Gy-Eq) exhibited 13.0 ± 0.85% PH cells (mean ± SEM) in the neutrophil population compared to 6.8 ± 1.6% in the low-dose group (n = 3, 0.29-0.86 Gy-Eq; p = 0.008). An age- and gender-matched control group (n = 8) exhibited 3.6 ± 0.9% PH cells. Results of a one-way ANOVA show that the high-dose group is statistically different from both the low-dose group and the control group (p = 0.002). However, the low-dose group is not statistically different from the control group (p = 0.122). The mean number of nuclear lobes in blood neutrophils was also enumerated as a function of time after exposure and was found to be diminished, consistent with incomplete nuclear segmentation that is characteristic of the Pelger Huet anomaly (PHA). In contrast to these changes in myeloid cells, the morphology of erythrocytes and platelets appeared to be normal. The authors conclude that ionizing radiation induces abnormal morphology of circulating neutrophils, which is similar to the pseudo-PHA that is acquired in disorders such as myelodysplastic syndrome, acute myeloid leukemia, and leukemoid reactions. Potential molecular mechanisms by which radiation induces this morphological change are discussed. From this cohort, the biomarker appears to be present early post-accident (accident. Assessment of circulating pseudo-Pelger Huet cells is being investigated as a potential biodosimetric tool.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-01-02

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

  3. Micronuclei in humans induced by exposure to low level of ionizing radiation: influence of polymorphisms in DNA repair genes

    Energy Technology Data Exchange (ETDEWEB)

    Angelini, Sabrina [Department of Pharmacology, University of Bologna, Via Irnerio 48, Bologna 40126 (Italy) and Department of Biosciences, Karolinska Institute, Novum, Huddinge 141 57 (Sweden)]. E-mail: angelini@biocfarm.unibo.it; Kumar, Rajiv [Department of Biosciences, Karolinska Institute, Novum, Huddinge 141 57 (Sweden); Division of Molecular Genetic Epidemiology, German Cancer Research Center (DKFZ), Heidelberg (Germany); Carbone, Fabio [Department of Pharmacology, University of Bologna, Via Irnerio 48, Bologna 40126 (Italy); Maffei, Francesca [Department of Pharmacology, University of Bologna, Via Irnerio 48, Bologna 40126 (Italy); Forti, Giorgio Cantelli [Department of Pharmacology, University of Bologna, Via Irnerio 48, Bologna 40126 (Italy); Violante, Francesco Saverio [Department of Biosciences, Karolinska Institute, Novum, Huddinge 141 57 (Sweden); Occupational Medicine Unit, S. Orsola-Malpighi Hospital, Via Pelagi 9, Bologna 40100 (Italy); Lodi, Vittorio [Department of Biosciences, Karolinska Institute, Novum, Huddinge 141 57 (Sweden); Curti, Stefania [Department of Biosciences, Karolinska Institute, Novum, Huddinge 141 57 (Sweden); Hemminki, Kari [Department of Biosciences, Karolinska Institute, Novum, Huddinge 141 57 (Sweden); Hrelia, Patrizia [Department of Pharmacology, University of Bologna, Via Irnerio 48, Bologna 40126 (Italy)

    2005-02-15

    Understanding the risks deriving from protracted exposure to low doses of ionizing radiation has remarkable societal importance in view of the large number of work settings in which sources of IR are encountered. To address this question, we studied the frequency of micronuclei (MN), which is an indicator of DNA damage, in a population exposed to low levels of ionizing radiation and in matched controls. In both exposed population and controls, the possible influence of single nucleotide polymorphisms in XRCC1, XRCC3 and XPD genes on the frequency of micronuclei was also evaluated. We also considered the effects of confounding factors, like smoking status, age and gender. The results indicated that MN frequency was significantly higher in the exposed workers than in the controls [8.62 {+-} 2.80 versus 6.86 {+-} 2.65; P = 0.019]. Radiological workers with variant alleles for XRCC1 or XRCC3 polymorphisms or wild-type alleles for XPD exon 23 or 10 polymorphisms showed a significantly higher MN frequency than controls with the same genotypes. Smoking status did not affect micronuclei frequency either in exposed workers or controls, while age was associated with increased MN frequency in the exposed only. In the combined population, gender but not age exerted an influence on the yield of MN, being higher in females than in males. Even though there is a limitation in this study due to the small number of subjects, these results suggest that even exposures to low level of ionizing radiation could have genotoxic effects and that XRCC3, XRCC1 and XPD polymorphisms might contribute to the increased genetic damage in susceptible individuals occupationally exposed to chronic low levels of ionizing radiation. For a clear conclusion on the induction of DNA damage caused by protracted exposure to low doses of ionizing radiation and the possible influence of genetic polymorphism in DNA repair genes larger studies are needed.

  4. Evaluation of the compatibility induced by ionizing radiation on polymeric blends

    Energy Technology Data Exchange (ETDEWEB)

    Pino, Eddy S.; Machado, Luci D.B., E-mail: lmachado@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Feitosa, Marcos A.F. [Centro Paula Souza, Faculdade de Tecnologia da Zona Leste, Sao Paulo, SP (Brazil); Giovedi, Claudia, E-mail: claudia.giovedi@ctmsp.mar.mil.b [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), Sao Paulo, SP (Brazil). Dept. de Tecnologia de Reatores Nucleares

    2011-07-01

    To produce new polymers is a costly and time consuming task. Therefore, the utilization of existing polymers in form of blends enables to obtain new polymeric materials at a competitive cost. In this sense, polymer blending has become a growing scientific and commercial development activity. In most of the cases, polymeric blends have immiscible components and this represents an unbecoming situation on blend design. For such immiscible blends, it is required the use of compatibilizers to gain properties advantage. Compatibilization process can be achieved by chemical handling using additives and heat. On the other hand, ionizing radiation induces compatibilization by free radicals, which improve the dispersion and adhesion of the blend phases, without use of chemical additives and at room temperature. In this work, a polyamide 6.6/low-density polyethylene 75/25% wt/wt composition blend was electron beam irradiated up to 250 kGy, and thereafter mechanical tests were carried out. Tensile measurements have shown that the strength at break increases, the elongation at break decreases, the resistance to impact decreases and hardness increases when the radiation dose increases. Since this mechanical behavior is due to cross-linking and to the radiation induced blend compatibilization, this compatibility was evaluated by the approach of the glass transition temperatures for both components using DMA measurements. The results have shown that the glass transition temperatures of the blend components got closer in 8 deg C in the irradiated sample, when compared to the glass transition temperature values obtained for non-irradiated blend. (author)

  5. Cumulative ionizing radiation exposure in patients with end stage kidney disease: a 6-year retrospective analysis.

    LENUS (Irish Health Repository)

    Coyle, Joe

    2011-08-13

    OBJECTIVE: To quantify cumulative exposure to ionizing radiation in patients with end stage kidney disease (ESKD). To investigate factors which may be independently associated with risk of high cumulative effective dose (CED). MATERIALS AND METHODS: The study had local institutional review board ethical approval. We conducted a retrospective study of 394 period prevalent ESKD patients attending a single tertiary referral centre between 2004 and 2009. Patient demographics were obtained from case records. Details of radiological investigations were obtained from the institutional radiology computerized database. CED was calculated using standard procedure specific radiation levels. High exposure was defined as CED > 50 mSv, an exposure which has been reported to increase cancer mortality by 5%. Data were compared using Pearson χ(2) and Mann-Whitney U test or Kruskal-Wallis tests. RESULTS: 394 patients were followed for a median of 4 years (1518 patient years follow-up). Of these 63% were male. Seventeen percent of patients had a CED of >50 mSv. Computed tomography (CT) accounted for 9% of total radiological studies\\/procedures while contributing 61.4% of total study dose. Median cumulative dose and median dose per patient year were significantly higher in the hemodialysis (HD) group (15.13 and 5.79 mSv, respectively) compared to the post-transplant group (2.9 and 0.52 mSv, respectively) (P < 0.001). CONCLUSION: ESKD patients are at risk of cumulative exposure to significant levels of diagnostic radiation. The majority of this exposure is imparted as a result of CT examinations to patients in the HD group.

  6. Obtention of gelatin biopolymers by ionizing radiation; Obtencao de biopolimeros de gelatina por radiacao ionizante

    Energy Technology Data Exchange (ETDEWEB)

    Takinami, Patricia Yoko Inamura

    2014-07-01

    The gelatin (Gel) is a biocompatible and biodegradable biopolymer, which naturally forms semi-solid colloids or hydrogels in aqueous solutions. As a hydrophilic polymer, the Gel has structural and physico-mechanical properties that distinguish it from synthetic hydrophilic polymers. The study of these properties led to the development of the present work. Thus, Gel-based films and hydrogels were developed using ionizing radiation technology by different techniques: irradiation with {sup 60}Co, electron beam (EB) and/or pulsed EB. The Gel based-films enriched with different additives, such as glycerol (GLY), polyvinyl alcohol (PVA), butylated hydroxytoluene (BHT), acrylamide and/or vegetal fiber, were irradiated with doses from 10 to 60 kGy, depending on the additive; some parameters like mechanical properties, color, and water absorption were analyzed. In the radio-induced synthesis of GEL nanohydrogels, polyethylene glycol (PEG) and the mixture (MIX) of additives, PEG and GEL, the size, molar mass and surface morphology of the nanohydrogels were analyzed. There was a significant increase of gel fraction with increase of the radiation dose for the GEL/fiber samples. The GEL based-films with 10% PVA irradiated at 20 kGy showed the highest puncture strength. The addition of antioxidant BHT affected on some GEL based-films properties on applied conditions. Regarding the nanohydrogels, there was a decrease of hydrodynamic radius of MIX irradiated with {sup 60}Co from 68 ± 25 nm (2 kGy) to 35 ± 4 nm (5 kGy). The radiation proved to be a convenient tool in the modification of polymeric materials for both, GEL films and hydrogels. (author)

  7. Concomitant treatment of F98 glioma cells with new liposomal platinum compounds and ionizing radiation.

    Science.gov (United States)

    Charest, Gabriel; Paquette, Benoit; Fortin, David; Mathieu, David; Sanche, Léon

    2010-04-01

    Despite significant advances, the radiotherapy and chemotherapy protocols marginally improve the overall survival of patients with glioblastoma. Lipoplatin(TM), and Lipoxal(TM), the liposomal formulations of cisplatin and oxaliplatin respectively, were tested on the F98 glioma cells for their ability to improve the cell uptake and increase the synergic effect when combined with ionizing radiation. The cytotoxicity and synergic effect of platinum compounds were assessed by colony formation assay, while the cellular uptake was measured by Inductively Coupled Plasma Mass Spectrometer (ICP-MS). After 4 h exposure with platinum compounds, cells were irradiated (1.5-6.6 Gy) with a (60)Co source. The liposomal formulations were compared to their liposome-free analogs and to carboplatin. The concomitant treatment of F98 cells with carboplatin and radiation produced the highest radiosensitizing effect (30-fold increase). Among the platinum compounds tested, Lipoplatin(TM) produced the most promising results. This liposomal formulation of cisplatin improved the cell uptake by 3-fold, and its radiosensitizing potential was enhanced by 14-fold. Although Lipoxal(TM) can potentially reduce the adverse effect of oxaliplatin, a synergic effect with radiation was measured only when incubated at a concentration higher than its IC50. Conversely, concomitant treatment with cisplatin did not result in a synergic effect, as in fact a radioprotective effect was measured on the F98 cells. In conclusion, among the five platinum compounds tested, carboplatin and Lipoplatin(TM) showed the best radiosensitizing effect. Lipoplatin(TM) seems the most promising since it led to the best cellular incorporation and has already been reported to be less neurotoxic than other platinum compounds.

  8. Radioprotective effect of the extract of Ziziphus joazeiro and Anacardium occidentale on embryos of Biomphalaria glabrata submitted to ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Siqueira, Williams N.; Silva, Luanna R.S.; Silva, Edvane B. [Universidade Federal de Pernambuco (DEN/UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear. Grupo de Estudos em Radioprotecao e Radioecologia; Silva, Ronaldo C. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Genetica; Lacerda, Laila B.N.; Silva, Hianna A.M.F.; Santos, Mariana L.O.; Sa, Jose L.F.; Melo, Ana M.M.A. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de de Biofisica e Radiobiologia. Lab. de Radiobiologia

    2011-07-01

    Electromagnetic radiations are energies that can be classified as non-ionizing and ionizing. This type of energy is propagated by a material medium and the vacuum. The important characteristic of ionizing radiation is the localized release of large amounts of energy. The biological effects of radiation result principally from damage to DNA, which is the critical target. Given these harmful effects caused by radiation highlights the importance of acquiring knowledge about the radioprotective substance, because they act to protect the living tissue, decreasing the damage he caused by the effects of radiation. In this study we investigated the radioprotective effect of extract hydroalcoholic of Ziziphus joazeiro and Anacardium occidentale on embryos of Biomphalaria glabrata. The embryos of Biomphalaria glabrata pigmented were divided into 18 groups of 100 specimens. The experimental groups were exposed to the extracts at a concentration of 200 ppm and then irradiated. For irradiation, we used a source of {sup 60}Co (Gammacell of Radionics Labs. Dose rate = 4.359 Gy/h). The viability of the embryos was examined using a stereoscopic microscope and statistical analysis was performed using the test Student-Newman-Keuls and {chi}{sup 2}. Our results showed that the extracts of hydroalcoholic Ziziphus joazeiro showed radioprotective effect and that the aqueous extract of the bark of Anacardium occidentale exhibited a reduction in its embryotoxic effect. (author)

  9. Infrared investigation of hard human teeth tissues exposed to various doses of ionizing radiation from the 1986 Chernobyl accident

    OpenAIRE

    Darchuk, L. A.; Zaverbna, L. V.; Bebeshko, V. G.; Worobiec, A.; Stefaniak, E. A.; Van Grieken, R.

    2008-01-01

    Infrared spectroscopy (IR) was applied to study changes in solid teeth tissues of persons exposed to low (0.12–0.20 Gy) and high (0.5–1.7 Gy) doses of ionizing radiation during their work in the Chernobyl zone after the accident. Changes in the inorganic and organic matrix of teeth were noted for both high and low radiation doses. The obtained results demonstrated that high doses of radiation lead to imbalance between phosphate–carbonate phases level (because of increasing of CO32− content) a...

  10. Clinical course of brain stroke in the persons exposed to ionizing radiation under the production conditions

    Energy Technology Data Exchange (ETDEWEB)

    Bouchmanov, A. [State Research Center of Russia, Moscow (Russian Federation). Inst. of Biophysics

    2000-05-01

    The purpose was to study the risk factors and clinical course of brain strokes in professionally exposed workers being employed in plutonium production in comparison with a control group. The method and materials of study -clinical supervision and clinical database creation on 162 cases of brain stroke (128 males and 34 females) developed among professionally exposed workers. Age of patient varied from 21 to 68 years (in average -51.6 y.). The control group consisted of patients with the same diagnosis, worked on the same enterprise, but non-exposed to radiation. Data on the totally accumulated dose of external gamma radiation were received on the base of the individual dosimeters (from 0.1 cSv to 52 cSv, in average about 13 cSv); the plutonium-239 body content was estimated accordingly to the level of urine radionuclide excretion (from 0.4 kBq to 1.6 kBq, in average about 0.33 kBq). Muscle's hypertinsion and pathological great-toe reflexes in paretic legs and hands, hemianopsia, impressive and ataxic aphasia prevailed in the patients with ischemic brain strokes in system of internal carotid artery, exposed to radiation. The changes of muscle's tension, ataxia and nystagmus were marked more often in the professionals with ischemic brain strokes in system of vertebrobasilar artery. The illness proceeded more easy and with smaller frequency of frustration of consciousness and algesthesia, irrespective of a type ischemic brain strokes in the people exposed to ionizing radiation, than in patients of non-irradiated group. It was found that the arterial hypertension appeared to be the main risk factor for the brain stroke in both groups of patients (in 81.48% and 91.15% of cases). There was no marked differences in significance of risk factors and in main clinical parameters of various types of ischemic brain strokes among the patients professionally exposed to radiation in comparison with a control group. (author)

  11. Theoretical astrophysics an introduction

    CERN Document Server

    Bartelmann, Matthias

    2013-01-01

    A concise yet comprehensive introduction to the central theoretical concepts of modern astrophysics, presenting hydrodynamics, radiation, and stellar dynamics all in one textbook. Adopting a modular structure, the author illustrates a small number of fundamental physical methods and principles, which are sufficient to describe and understand a wide range of seemingly very diverse astrophysical phenomena and processes. For example, the formulae that define the macroscopic behavior of stellar systems are all derived in the same way from the microscopic distribution function. This function it

  12. Nuclear astrophysics

    CERN Document Server

    Arnould, M

    1999-01-01

    Nuclear astrophysics is that branch of astrophysics which helps understanding some of the many facets of the Universe through the knowledge of the microcosm of the atomic nucleus. In the last decades much advance has been made in nuclear astrophysics thanks to the sometimes spectacular progress in the modelling of the structure and evolution of the stars, in the quality and diversity of the astronomical observations, as well as in the experimental and theoretical understanding of the atomic nucleus and of its spontaneous or induced transformations. Developments in other sub-fields of physics and chemistry have also contributed to that advance. Many long-standing problems remain to be solved, however, and the theoretical understanding of a large variety of observational facts needs to be put on safer grounds. In addition, new questions are continuously emerging, and new facts endanger old ideas. This review shows that astrophysics has been, and still is, highly demanding to nuclear physics in both its experime...

  13. Neutrino Astrophysics

    CERN Document Server

    Volpe, Cristina

    2016-01-01

    We summarize the progress in neutrino astrophysics and emphasize open issues in our understanding of neutrino flavor conversion in media. We discuss solar neutrinos, core-collapse supernova neutrinos and conclude with ultra-high energy neutrinos.

  14. Relativistic astrophysics

    CERN Document Server

    Demianski, Marek

    2013-01-01

    Relativistic Astrophysics brings together important astronomical discoveries and the significant achievements, as well as the difficulties in the field of relativistic astrophysics. This book is divided into 10 chapters that tackle some aspects of the field, including the gravitational field, stellar equilibrium, black holes, and cosmology. The opening chapters introduce the theories to delineate gravitational field and the elements of relativistic thermodynamics and hydrodynamics. The succeeding chapters deal with the gravitational fields in matter; stellar equilibrium and general relativity

  15. DIRECT DETECTION OF COMPLEX ORGANIC PRODUCTS IN ULTRAVIOLET (Lyα) AND ELECTRON-IRRADIATED ASTROPHYSICAL AND COMETARY ICE ANALOGS USING TWO-STEP LASER ABLATION AND IONIZATION MASS SPECTROMETRY

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, Bryana L.; Gudipati, Murthy S. [Science Division, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

    2015-02-10

    As discovery of complex molecules and ions in our solar system and the interstellar medium has proliferated, several groups have turned to laboratory experiments in an effort to simulate and understand these chemical processes. So far only infrared (IR) and ultraviolet (UV) spectroscopy has been able to directly probe these reactions in ices in their native, low-temperature states. Here we report for the first time results using a complementary technique that harnesses two-step two-color laser ablation and ionization to measure mass spectra of energetically processed astrophysical and cometary ice analogs directly without warming the ices—a method for hands-off in situ ice analysis. Electron bombardment and UV irradiation of H{sub 2}O, CH{sub 3}OH, and NH{sub 3} ices at 5 K and 70 K led to complex irradiation products, including HCO, CH{sub 3}CO, formamide, acetamide, methyl formate, and HCN. Many of these species, whose assignment was also strengthened by isotope labeling studies and correlate with IR-based spectroscopic studies of similar irradiated ices, are important ingredients for the building blocks of life. Some of them have been detected previously via astronomical observations in the interstellar medium and in cometary comae. Other species such as CH{sub 3}CO (acetyl) are yet to be detected in astrophysical ices or interstellar medium. Our studies suggest that electron and UV photon processing of astrophysical ice analogs leads to extensive chemistry even in the coldest reaches of space, and lend support to the theory of comet-impact-induced delivery of complex organics to the inner solar system.

  16. Structure and function of bone marrow hemopoiesis: mechanisms of response to ionizing radiation exposure.

    Science.gov (United States)

    Fliedner, T M; Graessle, D; Paulsen, C; Reimers, K

    2002-08-01

    It is the purpose of this presentation to review the unique structure and function of bone marrow anchored hematopoiesis in their significance for its response mechanisms to an exposure to ionizing radiation. The ultimate objective of bone marrow hematopoiesis is to maintain in the peripheral blood a constant level of the different blood cell types (erythrocytes, granulocytes, platelets, lymphocytes, etc.). All of them have their particular turnover kinetics (such as granulocytes 120 x 10(9)/d, erythrocytes 200 x 10(9)/d or thrombocytes 150 x 10(9)/d), are semi-autonomous in their steady state regulatory mechanisms and dependent on a life-long supply of mature cells from a stem cell pool with unlimited replicative and pluripotent differentiative potential. The present knowledge of hematopoietic cellular renewal is the result of years of basic experimental and clinical studies using radionuclides in various metabolic forms including (59)Fe, (32)P (DF (32)P), (51)Cr, (131)I, (60)Co, (3)H ((3)HTdR) and (14)C ((14)CTdR). To understand the physiology but in particular the radiation-pathophysiology, it is essential to recognize in detail the infrastructure of the bone marrow as a distinct unit. Indispensable for a life-long cell production is the capsule of the marrow - the bone cortex -, the arterial supply of blood connected to the sinusoidal microvascular architecture with its sinusoids contorti and recti as well as the central (cell collecting) sinusoids. It is further of importance to recognize the significance of nerval regulation of blood flow, characterized by myelinated and unmyelinated nerve fibers. The type of unique lining cells of the sinusoids is the prerequisite for the cell traffic between the hemopoietic parenchyma and the blood. This in turn cannot be achieved without an alternative opening and closing of the sinusoidal segments which - in turn - requires a rigid long capsule to assure an - in toto - constant volume of each bone marro