WorldWideScience

Sample records for astrophysical ionizing radiation

  1. 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

  2. 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.

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

    Science.gov (United States)

    Thomas, Brian C; Honeyman, Michelle D

    2008-08-01

    Abstract Various astrophysical events have been suggested as sources of ionizing radiation that, by way of destruction of the ozone layer and the subsequent increase in UVB and deposition of nitrate, could pose a threat to life on Earth. We have investigated whether the nitrate deposition that follows an ionizing event is sufficient to cause an additional stress beyond that of the heightened UVB previously considered. Our results show that, subsequent to the most intense ionization event likely to have occurred in the last billion years, the increase in nitrate concentration in bodies of water would not be sufficient to cause serious additional stress on amphibian populations and may actually provide some benefit by acting as fertilizer.

  4. 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.

  5. Radiation processes in astrophysics

    CERN Document Server

    Tucker, Wallace H

    1975-01-01

    The purpose of this book is twofold: to provide a brief, simple introduction to the theory of radiation and its application in astrophysics and to serve as a reference manual for researchers. The first part of the book consists of a discussion of the basic formulas and concepts that underlie the classical and quantum descriptions of radiation processes. The rest of the book is concerned with applications. The spirit of the discussion is to present simple derivations that will provide some insight into the basic physics involved and then to state the exact results in a form useful for applications. The reader is referred to the original literature and to reviews for rigorous derivations.The wide range of topics covered is illustrated by the following table of contents: Basic Formulas for Classical Radiation Processes; Basic Formulas for Quantum Radiation Processes; Cyclotron and Synchrotron Radiation; Electron Scattering; Bremsstrahlung and Collision Losses; Radiative Recombination; The Photoelectric Effect; a...

  6. Biological Effects of Ionizing Radiation

    Science.gov (United States)

    Ingram, M.; Mason, W. B.; Whipple, G. H.; Howland, J. W.

    1952-04-07

    This report presents a review of present knowledge and concepts of the biological effects of ionizing radiations. Among the topics discussed are the physical and chemical effects of ionizing radiation on biological systems, morphological and physiological changes observed in biological systems subjected to ionizing radiations, physiological changes in the intact animal, latent changes following exposure of biological systems to ionizing radiations, factors influencing the biological response to ionizing radiation, relative effects of various ionizing radiations, and biological dosimetry.

  7. 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.

  8. Biomedical Sensors of Ionizing Radiation

    OpenAIRE

    Pani, S; Speller, R; Royle, G; Olivo, A

    2010-01-01

    Sensors Technology Series Editor-in-Chief's Preface vii Preface ix 1 Biomedical Sensors: Temperature Sensor ... G. Kim Prisk 4 Biomedical Sensors of Ionizing Radiation 129 Robert Speller, Alessandro Olivo, Silvia Pani, and Gary Royle 5 ...

  9. The dosimetry of ionizing radiation

    CERN Document Server

    Bjaerngard, Bengt E; Kase, Kenneth R

    1987-01-01

    The Dosimetry of Ionizing Radiation, Volume II, attempts to fill the need for updated reference material on the field of radiation dosimetry. This book presents some broad topics in dosimetry and a variety of radiation dosimetry instrumentation and its application. The book opens with a chapter that extends and applies the concepts of microdosimetry to biological systems. This is followed by separate chapters on the state- of-the-art equipment and techniques used to determine neutron spectra; studies to determine recombination effects in ionization chambers exposed to high-intensity pulsed ra

  10. 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.

  11. 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.

  12. Space Flight Ionizing Radiation Environments

    Science.gov (United States)

    Koontz, Steve

    2017-01-01

    The space-flight ionizing radiation (IR) environment is dominated by very high-kinetic energy-charged particles with relatively smaller contributions from X-rays and gamma rays. The Earth's surface IR environment is not dominated by the natural radioisotope decay processes. Dr. Steven Koontz's lecture will provide a solid foundation in the basic engineering physics of space radiation environments, beginning with the space radiation environment on the International Space Station and moving outward through the Van Allen belts to cislunar space. The benefits and limitations of radiation shielding materials will also be summarized.

  13. Biochemistry of ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Walden, T.L.; Nushin, F.K.

    1990-01-01

    This volume examines the biochemical changes occurring in normal tissue after irradiation. A review of radiation chemistry is followed by an analysis of factors affecting biochemical responses and a timely discussion of radiobiology in space flight. The authors then describe the effects of radiation on lipid peroxidation, amino acids, peptides, proteins, polysaccharides, DNA, thiols, and body fluids. Close attention is given to alterations in biological mediators such as eicosanoids, cyclic nucleotides, angiotensin, histamine, polyamines, catecholamines, and serotonin and in hormones such as adrenocorticotropic hormone, testosterone, estrogens, follicle-stimulating hormone, luteinizing hormone, thyroid hormones, insulin and glucagon, gastrin, and melatonin. Other chapters focus on changes in carbohydrate metabolism, oxidative phosphorylation, protein synthesis, and serum proteins. A chapter on biological dosimeters discusses prodromal syndrome, hematological dosimeters, serum composition, urine, chromosomal aberrations, and fluorometric and immunoassays.

  14. 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 for...

  15. NMR Metabolomics in Ionizing Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Jian Z.; Xiao, Xiongjie; Hu, Mary Y.

    2016-09-08

    Ionizing radiation is an invisible threat that cannot be seen, touched or smelled and exist either as particles or waves. Particle radiation can take the form of alpha, beta or neutrons, as well as high energy space particle radiation such as high energy iron, carbon and proton radiation, etc. (1) Non-particle radiation includes gamma- and x-rays. Publically, there is a growing concern about the adverse health effects due to ionizing radiation mainly because of the following facts. (a) The X-ray diagnostic images are taken routinely on patients. Even though the overall dosage from a single X-ray image such as a chest X-ray scan or a CT scan, also called X-ray computed tomography (X-ray CT), is low, repeated usage can cause serious health consequences, in particular with the possibility of developing cancer (2, 3). (b) Human space exploration has gone beyond moon and is planning to send human to the orbit of Mars by the mid-2030s. And a landing on Mars will follow.

  16. Generation of polypeptide-templated gold nanoparticles using ionizing radiation.

    Science.gov (United States)

    Walker, Candace Rae; Pushpavanam, Karthik; Nair, Divya Geetha; Potta, Thrimoorthy; Sutiyoso, Caesario; Kodibagkar, Vikram D; Sapareto, Stephen; Chang, John; Rege, Kaushal

    2013-08-13

    Ionizing radiation, including γ rays and X-rays, are high-energy electromagnetic radiation with diverse applications in nuclear energy, astrophysics, and medicine. In this work, we describe the use of ionizing radiation and cysteine-containing elastin-like polypeptides (C(n)ELPs, where n = 2 or 12 cysteines in the polypeptide sequence) for the generation of gold nanoparticles. In the presence of C(n)ELPs, ionizing radiation doses higher than 175 Gy resulted in the formation of maroon-colored gold nanoparticle dispersions, with maximal absorbance at 520 nm, from colorless metal salts. Visible color changes were not observed in any of the control systems, indicating that ionizing radiation, gold salt solution, and C(n)ELPs were all required for nanoparticle formation. The hydrodynamic diameters of nanoparticles, determined using dynamic light scattering, were in the range of 80-150 nm, while TEM imaging indicated the formation of gold cores 10-20 nm in diameter. Interestingly, C2ELPs formed 1-2 nm diameter gold nanoparticles in the absence of radiation. Our results describe a facile method of nanoparticle formation in which nanoparticle size can be tailored based on radiation dose and C(n)ELP type. Further improvements in these polypeptide-based systems can lead to colorimetric detection of ionizing radiation in a variety of applications.

  17. Ionizing radiation and orthopaedic prostheses

    Science.gov (United States)

    Rimnac, Clare M.; Kurtz, Steven M.

    2005-07-01

    Ultra high molecular weight polyethylene (UHMWPE) materials have been used successfully as one half of the bearing couple (against metallic alloys or ceramics) in total hip and total knee joint replacements for four decades. This review describes the impact of ionizing radiation (used for sterilization and for microstructural modification via crosslinking) on the performance of UHMWPE total joint replacement components. Gamma radiation sterilization in air leads to oxidative degradation of UHMWPE joint components that occurs during shelf-aging and also during in vivo use. Efforts to mitigate oxidative degradation of UHMWPE joint components include gamma radiation sterilization in inert barrier-packaging and processing treatments to reduce free radicals. Ionizing radiation (both gamma and electron-beam) has recently been used to form highly crosslinked UHMWPEs that have better adhesive and abrasive wear resistance than non-crosslinked UHMWPE, thereby potentially improving the long-term performance of total joint replacements. Along with increased wear resistance, however, there are deleterious changes to ductility and fracture resistance of UHMWPE, and an increased risk of fracture of these components remains a clinical concern.

  18. 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)

  19. Ionizing radiation metrology. 1. ed.

    Energy Technology Data Exchange (ETDEWEB)

    Peixoto, Jose Guilherme P. (ed.)

    2014-07-01

    The main purpose of this publication is to review various concepts, fundamental topics and methods related to the primary or secondary measurements of ionizing radiation. Following the approach proposed by the BIPM Comite Consultatif pour les Etalons de Mesures des Rayonnements Ionisants, the book is fully devoted to three different aspects of metrology, namely: radionuclides and radioactivity; X-rays, Gamma, Electron and Charged Particles; Neutron metrology. Approaches inherent traceability, primary standard (absolute) and secondary (relative), assessment of uncertainties, nuclear instrumentation, and laboratory infrastructure were also contemplated herein. (author)

  20. Risks associated with ionizing radiation.

    Science.gov (United States)

    Little, M P

    2003-01-01

    This paper reviews current knowledge on the deterministic and stochastic risks (the latter including the risk of cancer and of hereditary disease) associated with exposure to ionizing radiation. Particular attention is paid to cancer risks following exposure to man-made low linear energy transfer radiation. Excess cancer risks have been observed in the Japanese atomic bomb survivors and in many medically and occupationally exposed groups. In general, the relative risks among Japanese survivors of atomic-bomb explosions are greater than those among comparable subsets in studies of medically exposed individuals. Cell sterilization largely accounts for the discrepancy in relative risks between these two populations, although other factors may contribute, such as the generally higher underlying cancer risks in the medical series than in the Japanese atomic bomb survivors. Risks among occupationally exposed groups such as nuclear workforces and underground miners are generally consistent with those observed in the Japanese atomic bomb survivors.

  1. 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 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.

  2. Animal Models of Ionizing Radiation Damage

    Science.gov (United States)

    1992-01-01

    level, some epithelial damage was observed (3). Michaelson, et al. (19) demonstrated that dogs developed hypothyroidism two to four years after expos... Pathophysiologic Signs of the Responses of the Nervous System to Ionizing Radiation, In Response of the Nervous System to Ionizing Radiation, Academic Press...Immunol. Ther. Exp., 10:416-459, 1962. 138. Krochak, R.J., and D.G. Baker, Radiation Nephritis. Clinical Manifestations and Pathophysiologic Mechanisms

  3. Radiative lifetimes for 80 levels of singly ionized erbium

    Energy Technology Data Exchange (ETDEWEB)

    Stockett, M H; Hartog, E A den; Lawler, J E [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States)

    2007-12-14

    Radiative lifetimes, accurate to {+-}5%, have been measured for 8 even-parity and 72 odd-parity levels of singly ionized erbium using time-resolved laser-induced fluorescence (LIF) on Er ions in a beam. This new set of measurements is more extensive than earlier LIF sets, and is in good agreement with those sets where they overlap. These lifetimes provide an absolute scale for a large, accurate set of Er{sup II} atomic transition probabilities. Basic spectroscopic data on rare earth transition probabilities are needed for astrophysical research and for research on lighting products.

  4. Ionizing radiation effects in MOS oxides

    CERN Document Server

    Oldham, Timothy R

    1999-01-01

    This volume is intended to serve as an updated critical guide to the extensive literature on the basic physical mechanisms controlling the radiation and reliability responses of MOS oxides. The last such guide was Ionizing Radiation Effects in MOS Devices and Circuits, edited by Ma and Dressendorfer and published in 1989. While that book remains an authoritative reference in many areas, there has been a significant amount of more recent work on the nature of the electrically active defects in MOS oxides which are generated by exposure to ionizing radiation. These same defects are also critical

  5. 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.

  6. (Oncogenic action of ionizing radiation)

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    An extensive experiment involving approximately 400 rats exposed to the neon ion beam at the Bevalac in Berkeley, CA and to electrons is nearing completion. The carcinogenicity of energetic electrons was determined for comparison with the neon ion results. As in past reports we will describe progress in three areas corresponding to the specific aims of the proposal: (1) carcinogenesis and DNA strand breaks in rat skin following exposure by the neon ions or electrons; (2) DNA strand breaks in the epidermis as a function of radiation penetration; (3) oncogene activation in radiation-induced rat skin cancers. 72 refs., 6 tabs.

  7. 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.

  8. Ionizing radiation transport in air

    Energy Technology Data Exchange (ETDEWEB)

    Klimanov, V.A.; Konovalov, S.A.; Kochanov, V.A.; Ksenofontov, A.I.; Kukhtevich, V.I.; Mashkovich, V.P.; Meshcherin, B.N.; Panchenko, A.M.; Sukhoruchkin, A.K.; Trubnikov, A.I.

    1979-01-01

    The book considers the problems of gamma-ray and neutron transport in air and near the air-ground and air-vacuum interface. New modifications of the Monte-Carlo method for solving these problems are presented. Differential and integral characteristics of gamma-ray, neutron, and secondary gamma-ray transport are given and the time characteristics of radiation sources are analyzed.

  9. Non-Ionizing Radiation Used in Microwave Ovens

    Science.gov (United States)

    ... in Microwave Ovens Non-Ionizing Radiation Used in Microwave Ovens Explore the interactive, virtual community of RadTown USA ! ... learn more About Non-Ionizing Radiation Used in Microwave Ovens Microwave Oven. Microwave ovens use electromagnetic waves that ...

  10. Ionizing radiation in earth's atmosphere and in space near earth.

    Science.gov (United States)

    2011-05-01

    The Civil Aerospace Medical Institute of the FAA is charged with identifying health hazards in air travel and in : commercial human space travel. This report addresses one of these hazards ionizing radiation. : Ionizing radiation is a subatomic p...

  11. Risks from ionizing radiation during pregnancy

    Directory of Open Access Journals (Sweden)

    mehrdad Gholami

    2007-04-01

    Full Text Available Gholami M1, Abedini MR2, Khossravi HR3, Akbari S4 1. Instructor, Department of medical physics, Faculty of medicine, Lorestan University of medical sciences 2. Assistant professor, Department of radiology, Faculty of medicine, Lorestan University of medical sciences 3. Assistant professor, Department of radiation protection, Iranian Atomic Energy Organization 4. Assistant professor, Department of gynecology, Faculty of medicine, Lorestan University of medical sciences Abstract Background: The discovery of the X-ray in November 1895 by the W. C. Roentgen caused the increasing use of x-ray, because of the benefits that patients get from the resultant the diagnosis. Since medical radiation exposure are mainly in artificial radiation sources, immediately after the x- ray discovery, progressive dermatitis and ophthalmic diseases were occurred in the early physicians and physicists. But delay effects were observed approximately 20 years after the x-ray discovery. History: Based on the studies, ionizing radiation is a potential hazard to the developing fetus, avoiding unnecessary radiation exposure to pregnant women is a standard practice in radiology, unless there are important clinical indications. Due to difference in stages of fetus development, using of the current radiation protection standards includes: justification of a practice, optimization of radiation protection procedures and dose limitation to prevent of serious radiation induced conditions is necessary. Conclusion: Conversely the somatic and genetic effects of x-rays, since the X-ray has the benefit effects, special in diagnostic and treatment procedures, there is increasing use of x-ray, so using of the latest radiation protection procedures is necessary. Radiation protection not only is a scientific subject but also is a philosophy, Moral and reasonable. since the ionizing radiation is a potential hazard to the developing fetus, avoiding unnecessary radiation exposure to the pregnant

  12. Measurement of indoor background ionizing radiation in some ...

    African Journals Online (AJOL)

    Certain types of building materials are known to be radioactive. Exposure to indoor ionizing radiation like exposure to any other type of ionizing radiation results in critical health challenges. Measurement of the background ionizing radiation profile within the Chemistry Research Laboratory and Physics Laboratory III all of ...

  13. Radiative lifetimes of singly ionized cerium

    Energy Technology Data Exchange (ETDEWEB)

    Hartog, E A Den; Lawler, J E [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States)], E-mail: eadenhar@wisc.edu, E-mail: jelawler@wisc.edu

    2008-02-28

    Radiative lifetimes accurate to {+-}5% have been measured for 74 levels in Ce II using time-resolved laser-induced fluorescence on a slow beam of cerium ions. The 17 odd-parity and 57 even-parity levels studied here lie in the energy range 24 000-36 000 cm{sup -1}. This new set of lifetimes in Ce II is substantially more extensive than previously published sets, to which a detailed comparison is made. The present lifetime results will provide the absolute calibration for a very large set of measured transition probabilities for Ce II. These are needed for research in astrophysics and lighting.

  14. Bacterial and archaeal resistance to ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Confalonieri, F; Sommer, S, E-mail: fabrice.confalonieri@u-psud.fr, E-mail: suzanne.sommer@u-psud.fr [University Paris-Sud, CNRS UMR8621, Institut de Genetique et Microbiologie, Batiments 400-409, Universite Paris-Sud, 91405 Orsay (France)

    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

  15. Genetic variation in resistance to ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ayala, F.J.

    1989-01-01

    The very reactive superoxide anion O[sub 2] is generated during cell respiration as well as during exposure to ionizing radiation. Organisms have evolved different mechanisms to protect against the deleterious effects of reduced oxygen species. The copper-zinc superoxide dismutase is a eukaryotic cytoplasmic enzyme that protects the cell by scavenging superoxide radicals and dismutating them to hydrogen peroxide and molecular oxygen: 20[sub 2][sup [minus

  16. Alloy nanoparticle synthesis using ionizing radiation

    Science.gov (United States)

    Nenoff, Tina M [Sandia Park, NM; Powers, Dana A [Albuquerque, NM; Zhang, Zhenyuan [Durham, NC

    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.

  17. 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.

  18. Ordering of crystal structure by ionizing radiation

    Science.gov (United States)

    Chernov, I. P.; Momontov, A. P.; Cherdantsev, P. A.; Chakhlov, B. V.

    1994-12-01

    We have studied the action of ionizing radiation on defect-containing semiconductor crystals, metals, and alloys. Using modern methods for investigation of solids, Rutherford back scattering of channeled charged particles, x-ray diffraction, electron microscopy, and also calorimetric methods, we have established: a) irradiation (by x-ray beams, gamma rays, and electrons) of metals and alloys with an equivalent radiation dose less than 105 J/kg and of semiconductor crystals with a dose less than 103 J/kg does not lead to additional accumulation of defects but conversely leads to elimination of defects and transition of the crystal to a more equilibrium state; b) ionization processes play a determining role in rearrangment of defects in crystals exhibiting both semiconductor and metallic conductivity. We show that rearrangment of the crystal occurs as a result of stored energy in the crystal which is liberated due to chain reactions of annihilation of defects, initiated by ionization. Transition of the crystal to the equilibrium state is accompanied by improvement of its physical properties.

  19. Importance of electric fields from ionized nanoparticles for radiation therapy

    Science.gov (United States)

    Shmatov, M. L.

    2017-05-01

    A model is presented in which electric fields from ionized particles in a biological tissue enhance the biological effect of ionizing radiation. The model is based on the data on enhancing the gamma radiation effect on biological cells by static electric fields and on estimates of the typical intensities of electric fields from ionized nanoparticles in a biological tissue.

  20. Method and apparatus to monitor a beam of ionizing radiation

    Science.gov (United States)

    Blackburn, Brandon W.; Chichester, David L.; Watson, Scott M.; Johnson, James T.; Kinlaw, Mathew T.

    2015-06-02

    Methods and apparatus to capture images of fluorescence generated by ionizing radiation and determine a position of a beam of ionizing radiation generating the fluorescence from the captured images. In one embodiment, the fluorescence is the result of ionization and recombination of nitrogen in air.

  1. Radar detection of radiation-induced ionization in air

    Science.gov (United States)

    Gopalsami, Nachappa; Heifetz, Alexander; Chien, Hual-Te; Liao, Shaolin; Koehl, Eugene R.; Raptis, Apostolos C.

    2015-07-21

    A millimeter wave measurement system has been developed for remote detection of airborne nuclear radiation, based on electromagnetic scattering from radiation-induced ionization in air. Specifically, methods of monitoring radiation-induced ionization of air have been investigated, and the ionized air has been identified as a source of millimeter wave radar reflection, which can be utilized to determine the size and strength of a radiation source.

  2. Ionizing radiation--understanding and acceptance.

    Science.gov (United States)

    Mihai, Laurentiu Teodor; Milu, Constantin; Voicu, Bogdan; Enachescu, Dan

    2005-10-01

    A written survey about perceived radiation risks was conducted among three groups of a total of 400 individuals. Seventy-seven (26%) of the respondents were radiation workers, 35 (12%) were medical doctors without professional exposure, and 177 (68%) belonged to the general population. Even if the sample is not representative of the Romanian population as a whole, some interesting conclusions can be made. The level of anxiety toward radiation, expressed as a hazard perception index, is significantly lower in radiation workers when compared to medical doctors and the general population (0.81 +/- 0.94, 1.42 +/- 1.21, and 1.72 +/- 1.34, respectively, p < 0.001). Hazard perception index values also varied with the education status, with lowest values among medical university graduates and highest among public school graduates (p < 0.001). Both university-graduated groups significantly differ from the non-university groups (p < 0.05). Knowledge about radiation and emergency plans for nuclear accidents/incidents was also correlated with hazard perception, with the results confirming the hypothesis that better knowledge is associated with lower radiation hazard perception. The extent to which people accept civilian nuclear power is also related to hazard perception and knowledge. The way people perceive the radiation risk differed among the three groups. Different levels of risk perception were associated with radiation from nuclear energy and diagnostic x rays. It is important that radiological protection authorities develop new plans and materials for communicating with the general public in order to improve knowledge of ionizing radiation, radiation risks, and the safety of civilian nuclear energy employment.

  3. How does ionizing radiation escape from galaxies?

    Science.gov (United States)

    Orlitova, Ivana

    2016-10-01

    Search for sources that reionized the Universe from z 15 to z 6 is one of the main drivers of present-day astronomy. Low-mass star-forming galaxies are the most favoured sources of ionizing photons, but the searches of escaping Lyman continuum (LyC) have not been extremely successful. Our team has recently detected prominent LyC escape from five Green Pea galaxies at redshift 0.3, using the HST/COS spectrograph, which represents a significant breakthrough. We propose here to study the LyC escape of the strongest among these leakers, J1152, with spatial resolution. From the comparison of the ionizing and non-ionizing radiation maps, and surface brightness profiles, we will infer the major mode in which LyC is escaping: from the strongest starburst, from the galaxy edge, through a hole along our line-of-sight, through clumpy medium, or directly from all the production sites due to highly ionized medium in the entire galaxy. In parallel, we will test the predictive power of two highly debated indirect indicators of LyC leakage: the [OIII]5007/[OII]3727 ratio, and Lyman-alpha. We predict that their spatial distribution should closely follow that of the ionizing continuum if column densities of the neutral gas are low. This combined study, which relies on the HST unique capabilities, will bring crucial information on the structure of the leaking galaxies, provide constraints for hydrodynamic simulations, and will lead to efficient future searches for LyC leakers across a large range of redshifts.

  4. Sterilization of skin allografts by ionizing radiation.

    Science.gov (United States)

    Bourroul, Selma Cecília; Herson, Marisa Roma; Pino, Eddy; Matho, Monica Beatriz

    2002-11-01

    The skin has a fundamental role in the viability of human body. In the case of extensive wounds, skin allografts provide an alternative to cover temporarily the damaged areas. After donor screening and preservation in glycerol 85%, the skin can be stored in a Skin Bank. Glycerol at this concentration has a bacteriostatic effect after certain time of preservation. On the other hand, skin sterilization by ionizing radiation may reduce the quarentine period for transplantation in patients. The objective of this work was to evaluate allograft sterilization using two sources of ionizing radiation. Through the analysis of stress-strain, it was intended to verify possible effects of the radiation on the structure of preserved grafts. Three groups of skin samples were selected. The first group was maintained in the initial conditions, not irradiated. The second was exposed to cobalt-60, while the third one was irradiated using an Dynamitron Accelerator JOB188 electron beam. The irradiation dose was 25 kGy for both tests. Both irradiation sources, and the Instron Universal Machine used for biomechanical experiments, are installed at the Centro de Tecnologia das Radiações/Instituto de Pesquisas Energéticas e Nucleares (São Paulo, Brazil). According to the preliminary results, biomechanical characteristics of the samples irradiated seem to be maintained with regard to the non irradiated group.

  5. 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.

  6. Sterilization of therapeutic immunoadsorbents by ionizing radiation.

    Science.gov (United States)

    Sato, H; Kidaka, T; Hori, M

    1986-03-01

    The application of ionizing radiation (gamma-rays from 60Co) to sterilize therapeutic immunoadsorbents (IA)s was investigated. The IAs were porous bead carriers immobilizing anti-IgE antibodies and were irradiated in both the freeze-dried and precipitated (wet) states. The IgE removal (%), the IgE adsorption capacity of IA, was acceptable in terms of practical use even after an irradiation dose of 2.5 Mrad in the precipitated state; the anti-IgE antibody itself lost much of its activity, possibly because of intermolecular crosslinking of antibody molecules, after being irradiated with a dose at least of 0.5 Mrad. In the freeze-dried state only IA consisting of CPG-1400 could tolerate a dose of 2.5 Mrad. Dose-survival curves were obtained using Bacillus pumilus spores in both the freeze-dried and precipitated IAs and the D-values were calculated to be respectively 0.27 and 0.31 Mrad. Thus, ionizing radiation may be applicable for sterilizing IAs in the precipitated state and in the freeze-dried state for an IA consisting of CPG-1400 although the initial bioburden on IA should be low.

  7. 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.

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

    Science.gov (United States)

    Poujade, Olivier; Bonnefille, Max; Vandenboomgaerde, Marc

    2015-11-01

    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 us to understand extra 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. Management of ionizing radiation injuries and illnesses, part 1: physics, radiation protection, and radiation instrumentation.

    Science.gov (United States)

    Christensen, Doran M; Jenkins, Mark S; Sugarman, Stephen L; Glassman, Erik S

    2014-03-01

    Ionizing radiation injuries and illnesses are exceedingly rare; therefore, most physicians have never managed such conditions. When confronted with a possible radiation injury or illness, most physicians must seek specialty consultation. Protection of responders, health care workers, and patients is an absolute priority for the delivery of medical care. Management of ionizing radiation injuries and illnesses, as well as radiation protection, requires a basic understanding of physics. Also, to provide a greater measure of safety when working with radioactive materials, instrumentation for detection and identification of radiation is needed. Because any health care professional could face a radiation emergency, it is imperative that all institutions have emergency response plans in place before an incident occurs. The present article is an introduction to basic physics, ionizing radiation, radiation protection, and radiation instrumentation, and it provides a basis for management of the consequences of a radiologic or nuclear incident.

  10. Decontamination of pesticide packing using ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Duarte, C.L. [Instituto de Pesquisas Energeticas e Nucleares-IPEN-CNEN/SP Av. Lineu Prestes 2.242, 05508-900, Sao Paulo, SP (Brazil)], E-mail: clduarte@ipen.br; Mori, M.N.; Kodama, Yasko; Oikawa, H.; Sampa, M.H.O. [Instituto de Pesquisas Energeticas e Nucleares-IPEN-CNEN/SP Av. Lineu Prestes 2.242, 05508-900, Sao Paulo, SP (Brazil)

    2007-11-15

    The Brazilian agriculture activities have consumed about 288,000 tons of pesticides per year conditioned in about 107,000,000 packing with weight of approximately 23,000 tons. The discharge of empty plastic packing of pesticides can be an environmental concern causing problems to human health, animals, and plants if done without inspection and monitoring. The objective of this work is to study the ionizing radiation effect in the main pesticides used in Brazil for plastic packing decontamination. Among the commercial pesticides, chlorpyrifos has significant importance because of its wide distribution and extensive use and persistence. The radiation-induced degradation of chlorpyrifos in liquid samples and in polyethylene pack was studied by gamma radiolysis. Packing of high-density polyethylene (HDPE) three layer coextruded, named COEX, contaminated with chlorpyrifos, were irradiated using both a multipurpose Co-60 gamma irradiator and a gamma source with 5000 Ci total activity Gamma cell type. The chemical analysis of the chlorpyrifos was made using a gas chromatography associated to the Mass Spectrometry-GCMS from Shimadzu Model QP 5000. Gamma radiation was efficient for removing chlorpyrifos from the plastic packing, in all studied cases.

  11. Environmental Ionizing Radiation Survey of Quarry Sites in Ilorin ...

    African Journals Online (AJOL)

    NJABS

    ABSTRACT: An environmental ionizing radiation survey around quarry sites in Ilorin was carried out using three. Radalert ... they live in areas with radiation doses above normal background .... also maintaining all exposure levels "as low as.

  12. 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.

  13. 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

  14. Review of health effects of non-ionizing radiations | Ughachukwu ...

    African Journals Online (AJOL)

    Non-ionizing radiations (electromagnetic waves) consist of electric and magnetic waves travelling together. In decreasing order of ... For example, non-ionizing radiations increase cellular generation of free radicals, disrupt the blood-brain barrier, and decrease cognitive functions of the brain. These result in genotoxic ...

  15. Extreme Ionizing-Radiation-Resistant Bacterium

    Science.gov (United States)

    Vaishampayan, Parag A.; Venkateswaran, Kasthuri J.; Schwendner, Petra

    2013-01-01

    There is a growing concern that desiccation and extreme radiation-resistant, non-spore-forming microorganisms associated with spacecraft surfaces can withstand space environmental conditions and subsequent proliferation on another solar body. Such forward contamination would jeopardize future life detection or sample return technologies. The prime focus of NASA s planetary protection efforts is the development of strategies for inactivating resistance-bearing micro-organisms. Eradi cation techniques can be designed to target resistance-conferring microbial populations by first identifying and understanding their physiologic and biochemical capabilities that confers its elevated tolerance (as is being studied in Deinococcus phoenicis, as a result of this description). Furthermore, hospitals, food, and government agencies frequently use biological indicators to ensure the efficacy of a wide range of radiation-based sterilization processes. Due to their resistance to a variety of perturbations, the nonspore forming D. phoenicis may be a more appropriate biological indicator than those currently in use. The high flux of cosmic rays during space travel and onto the unshielded surface of Mars poses a significant hazard to the survival of microbial life. Thus, radiation-resistant microorganisms are of particular concern that can survive extreme radiation, desiccation, and low temperatures experienced during space travel. Spore-forming bacteria, a common inhabitant of spacecraft assembly facilities, are known to tolerate these extreme conditions. Since the Viking era, spores have been utilized to assess the degree and level of microbiological contamination on spacecraft and their associated spacecraft assembly facilities. Members of the non-sporeforming bacterial community such as Deinococcus radiodurans can survive acute exposures to ionizing radiation (5 kGy), ultraviolet light (1 kJ/m2), and desiccation (years). These resistive phenotypes of Deinococcus enhance the

  16. 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.

  17. Environmental Ionizing Radiation Survey of Quarry Sites in Ilorin ...

    African Journals Online (AJOL)

    An environmental ionizing radiation survey around quarry sites in Ilorin was carried out using three Radalert Nuclear Radiation Monitors and Global Positioning System (GPS) in order to assess and provide up to date information on radiation levels in the environment. Measured mean radiation levels ranged from 1.11±0.05 ...

  18. The Hazards of Non-Ionizing Radiation of Telecommunication Mast ...

    African Journals Online (AJOL)

    This study therefore establishes that there are health implications of exposure to mast radiation and minimizing them will go a long way to improve healthy living. Keywords: Hazard, non-ionizing radiation, telecommunication, mast, electromagnetic radiation, radio-frequency radiation, exposure, wireless telephone, antenna.

  19. The Effects of Ionizing Radiation on the Oral Cavity.

    Science.gov (United States)

    de Barros da Cunha, Sandra Ribeiro; Ramos, Pedro Augusto Mendes; Nesrallah, Ana Cristina Aló; Parahyba, Cláudia Joffily; Fregnani, Eduardo Rodrigues; Aranha, Ana Cecília Corrêa

    2015-08-01

    The aim of this study is to present a literature review on the effects of the ionizing radiation from radiotherapy treatment on dental tissues. Among the effects of increasing global life expectancy and longevity of the teeth in the oral cavity, increasing rates of neoplastic diseases have been observed. One of the important treatment modalities for head and neck neoplastic diseases is radiotherapy, which uses ionizing radiation as the main mechanism of action. Therefore, it is essential for dentists to be aware of the changes in oral and dental tissues caused by ionizing radiation, and to develop treatment and prevention strategies. In general, there is still controversy about the effects of ionizing radiation on dental structures. However, qualitative and quantitative changes in saliva and oral microbiota, presence of oral mucositis and radiation-related caries are expected, as they represent the well-known side effects of treatment with ionizing radiation. Points that still remain unclear are the effects of radiotherapy on enamel and dentin, and on their mechanisms of bonding to contemporary adhesive materials. Ionizing radiation has shown important interaction with organic tissues, since more deleterious effects have been shown on the oral mucosa, salivary glands and dentin, than on enamel. With the increasing number of patients with cancer seeking dental treatment before and after head and neck radiotherapy, it is important for dentists to be aware of the effects of ionizing radiation on the oral cavity.

  20. (KNa)Br phosphor for ionizing radiation dosimetry

    Indian Academy of Sciences (India)

    Lyoluminescence; γ-ray dose; radiation dosimetry; phosphor; (KNa)Br. 1. Introduction. The measurement of radiation dose has become a science of ever increasing importance due to the estimation of risk and benefits inherent to the uses and to the exposure of ionizing radiation. When strongly energized, crystals are ...

  1. 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.

  2. [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.

  3. Effect of Ionizing Radiation on STT-RAM Multilayers

    Science.gov (United States)

    2017-03-01

    Effect of Ionizing Radiation on STT-RAM Multilayers Mikael Nilsson1,2, Ilya Krivorotov3, Ozdal Boyraz4, Nader Bagherzadeh4, Randy Ngelale1...process. We present here our initial results on the effect of radiation on a typical STT-RAM magnetic multilayer stack. The multilayers were...exposed to both gamma radiation and a mix of gamma and neutron, using our TRIGA® reactor. The effect of radiation on magnetic anisotropy and damping of

  4. Knowledge and attitude of European urology residents about ionizing radiation.

    Science.gov (United States)

    Söylemez, Haluk; Sancaktutar, Ahmet Ali; Silay, Mesrur Selcuk; Penbegül, Necmettin; Bozkurt, Yaşar; Atar, Murat; Altunoluk, Bülent; Bodakci, Mehmet Nuri; Hatipoglu, Namık Kemal

    2013-01-01

    To evaluate the attitude and knowledge of urology residents concerning ionizing radiation, we undertook a survey of European urology residents. The questionnaire was sent to 1184 urology residents within the database of the European Society of Residents in Urology (ESRU) by e-mail between November 2011 and January 2012. The questionnaire was composed of demographic questions and questions about the frequency of radiation exposure and use of radiation safety measures during fluoroscopy-guided endourologic procedures. In addition, there were questions about education programs and respondents' knowledge about diagnostic imaging modalities. A total of 124 questionnaires were returned from urology residents in 20 different European countries. All of the respondents reported that they were routinely exposed to ionizing radiation, and 69 (72.5%) were exposed more than 3 times per week. Despite the common but not sufficient use of lead aprons (75%), use of other radiation protection measures was very low. Although 55% of the respondents had attended an education program in Europe about radiation safety, attendance was highest in Poland (82.6%). The level of knowledge about ionizing radiation was low among urology residents, and approximately half of responders had no idea that commonly used imaging modalities have a fatal cancer risk. The results of this study showed the lack of knowledge and awareness about the importance of ionizing radiation protection among urology residents in Europe. We therefore suggest radiation safety courses in every step of medical life for doctors, especially for endourologists. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. Ionizing Radiation: The Good, the Bad, and the Ugly

    Science.gov (United States)

    Ryan, Julie L.

    2013-01-01

    Skin changes from ionizing radiation have been scientifically documented since 1902 (Hymes et al., 2006). Ionizing radiation is a widely accepted form of treatment for various types of cancer. Despite the technological advances, radiation skin injury remains a significant problem. This injury, often referred to as radiation dermatitis, occurs in about 95% of patients receiving radiation therapy for cancer and ranges in severity from mild erythema to moist desquamation and ulceration (McQuestion, 2011; Salvo et al., 2010). Ionizing radiation is not only a concern for cancer patients, but also a public health concern due to the potential for and reality of a nuclear and/or radiological event. Recently, the United States has increased efforts to develop medical countermeasures to protect against radiation toxicities from acts of bioterrorism, as well as cancer treatment. Management of radiation dermatitis would improve the therapeutic benefit of radiation therapy for cancer and potentially the mortality expected in any “dirty bomb” attack (Benderitter et al., 2010; Muller and Meineke, 2010). Currently, there is no effective treatment to prevent or mitigate radiation skin injury. This review summarizes “the good, the bad and the ugly” of current and evolving knowledge regarding mechanisms of and treatments for radiation skin injury. PMID:22217743

  6. 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

  7. Effects of ionizing radiation on papayas ( Carica papaya ) fruit | Orji ...

    African Journals Online (AJOL)

    The effects of ionizing radiation on papaya fruits were investigated with a particular interest on the disinfection and ripening. Twelve samples of papayas fruit, each weighing between 400 – 450 g were irradiated over four different regimes of radiation doses: 0.25, 0.50, 0.75 and 1.00 kGy, using a cobalt-60 gamma irradiation ...

  8. CARCINOGENIC EFFECTS OF LOW DOSES OF IONIZING RADIATION

    Science.gov (United States)

    Carcinogenic Effects of Low Doses of Ionizing RadiationR Julian Preston, Environmental Carcinogenesis Division, NHEERL, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711The form of the dose-response curve for radiation-induced cancers, particu...

  9. Scattered ionizing radiations from low-energy focus plasma and ...

    Indian Academy of Sciences (India)

    Scattered ionizing radiations from low-energy focus plasma and radiation dosimetery assessment. G M EL-ARAGI∗, M A AYAD, M A EL-KOLALY and .... 4000 system is in coaxial connection with a computer system which has a special software program for resolving TL-data and assorting the resolved data in classified files.

  10. Assessment of exposure to ionizing radiation at selected mining ...

    African Journals Online (AJOL)

    This paper investigated the levels of ionizing radiation at selected mining sites in Nasarawa State, Nigeria. Inspector alert nuclear radiation meter (S.E. International, USA SN: 35440) was used for these assessments. The meter was held at the abdominal level (about 1 m above ground level) and readings were taken in ...

  11. Genetic variation in resistance to ionizing radiation. [Annual report, 1989

    Energy Technology Data Exchange (ETDEWEB)

    Ayala, F.J.

    1989-12-31

    The very reactive superoxide anion O{sub 2} is generated during cell respiration as well as during exposure to ionizing radiation. Organisms have evolved different mechanisms to protect against the deleterious effects of reduced oxygen species. The copper-zinc superoxide dismutase is a eukaryotic cytoplasmic enzyme that protects the cell by scavenging superoxide radicals and dismutating them to hydrogen peroxide and molecular oxygen: 20{sub 2}{sup {minus}} + 2H {yields} H{sub 2}O{sub 2} + O{sub 2}. SOD had been shown to protect against ionizing radiation damage to DNA, viruses, bacteria, mammalian cells, whole mice, and Drosophila. Evidence that genetic differences may affect sensitivity to ionizing radiation has been shown in Drosophila since differences have been shown to exist between strains and resistance to radiation can evolve under natural selection.

  12. 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.

  13. 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.

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

    OpenAIRE

    Agnieszka Anna Domańska; Małgorzata Bieńkiewicz; Jerzy Olszewski

    2013-01-01

    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 uni...

  15. 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.

  16. MOSFET and MOS capacitor responses to ionizing radiation

    Science.gov (United States)

    Benedetto, J. M.; Boesch, H. E., Jr.

    1984-01-01

    The ionizing radiation responses of metal oxide semiconductor (MOS) field-effect transistors (FETs) and MOS capacitors are compared. It is shown that the radiation-induced threshold voltage shift correlates closely with the shift in the MOS capacitor inversion voltage. The radiation-induced interface-state density of the MOSFETs and MOS capacitors was determined by several techniques. It is shown that the presence of 'slow' states can interfere with the interface-state measurements.

  17. CANCER RISKS ATTRIBUTABLE TO LOW DOSES OF IONIZING RADIATION - ASSESSING WHAT WE REALLY KNOW?

    Science.gov (United States)

    Cancer Risks Attributable to Low Doses of Ionizing Radiation - What Do We Really Know?AbstractHigh doses of ionizing radiation clearly produce deleterious consequences in humans including, but not exclusively, cancer induction. At very low radiation doses the situatio...

  18. 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)

  19. 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.

  20. 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.)

  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. CVD diamond detectors for ionizing radiation

    CERN Document Server

    Friedl, M; Bauer, C; Berfermann, E; Bergonzo, P; Bogani, F; Borchi, E; Brambilla, A; Bruzzi, Mara; Colledani, C; Conway, J; Dabrowski, W; Delpierre, P A; Deneuville, A; Dulinski, W; van Eijk, B; Fallou, A; Fizzotti, F; Foulon, F; Gan, K K; Gheeraert, E; Grigoriev, E; Hallewell, G D; Hall-Wilton, R; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Kagan, H; Kania, D R; Kaplon, J; Karl, C; Kass, R; Knöpfle, K T; Krammer, Manfred; Lo Giudice, A; Lü, R; Manfredi, P F; Manfredotti, C; Marshall, R D; Meier, D; Mishina, M; Oh, A; Pan, L S; Palmieri, V G; Pernegger, H; Pernicka, Manfred; Peitz, A; Pirollo, S; Polesello, P; Pretzl, Klaus P; Re, V; Riester, J L; Roe, S; Roff, D G; Rudge, A; Schnetzer, S R; Sciortino, S; Speziali, V; Stelzer, H; Stone, R; Tapper, R J; Tesarek, R J; Thomson, G B; Trawick, M L; Trischuk, W; Vittone, E; Walsh, A M; Wedenig, R; Weilhammer, Peter; Ziock, H J; Zöller, M

    1999-01-01

    In future HEP accelerators, such as the LHC (CERN), detectors and electronics in the vertex region of the experiments will suffer from extreme radiation. Thus radiation hardness is required for both detectors and electronics to survive in this harsh environment. CVD diamond, which is investigated by the RD42 Collaboration at CERN, can meet these requirements. Samples of up to 2*4 cm/sup 2/ have been grown and refined for better charge collection properties, which are measured with a beta source or in a test beam. A large number of diamond samples has been irradiated with hadrons to fluences of up to 5*10/sup 15/ cm/sup -2/ to study the effects of radiation. Both strip and pixel detectors were prepared in various geometries. Samples with strip metallization have been tested with both slow and fast readout electronics, and the first diamond pixel detector proved fully functional with LHC electronics. (16 refs).

  3. Detection of Ionizing Radiation using Solar Blind Air Fluorescence

    Science.gov (United States)

    2013-06-01

    either PMTs or MCPs . These detectors are intrinsically solar blind and may provide much higher detection efficiency (10-25%) than CsTe/Filter PMT or MCP ...possibility of detection in full daylight. If a practical detector could be realized utilizing this detection technique it would offer the following...benefits over existing radiation detection methods: • Standoff imaging detection of ionizing radiation. Such a detector would provide information on source

  4. 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.

  5. 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.)

  6. Radioprotective agents to prevent cellular damage due to ionizing radiation.

    Science.gov (United States)

    Smith, Tyler A; Kirkpatrick, Daniel R; Smith, Sean; Smith, Trevor K; Pearson, Tate; Kailasam, Aparna; Herrmann, Kortney Z; Schubert, Johanna; Agrawal, Devendra K

    2017-11-09

    Medical imaging has become a central component of patient care to ensure early and accurate diagnosis. Unfortunately, many imaging modalities use ionizing radiation to generate images. Ionizing radiation even in low doses can cause direct DNA damage and generate reactive oxygen species and free radicals, leading to DNA, protein, and lipid membrane damage. This cell damage can lead to apoptosis, necrosis, teratogenesis, or carcinogenesis. As many as 2% of cancers (and an associated 15,000 deaths annually) can be linked to computed tomography exposure alone. Radioprotective agents have been investigated using various models including cells, animals, and recently humans. The data suggest that radioprotective agents working through a variety of mechanisms have the potential to decrease free radical damage produced by ionizing radiation. Radioprotective agents may be useful as an adjunct to medical imaging to reduced patient morbidity and mortality due to ionizing radiation exposure. Some radioprotective agents can be found in high quantities in antioxidant rich foods, suggesting that a specific diet recommendation could be beneficial in radioprotection.

  7. EPR-dosimetry of ionizing radiation

    Science.gov (United States)

    Popova, Mariia; Vakhnin, Dmitrii; Tyshchenko, Igor

    2017-09-01

    This article discusses the problems that arise during the radiation sterilization of medical products. It is propose the solution based on alanine EPR-dosimetry. The parameters of spectrometer and methods of absorbed dose calculation are given. In addition, the problems that arise during heavy particles irradiation are investigated.

  8. HADES code for numerical simulations of high-mach number astrophysical radiative flows

    Science.gov (United States)

    Michaut, C.; Di Menza, L.; Nguyen, H. C.; Bouquet, S. E.; Mancini, M.

    2017-03-01

    The understanding of astrophysical phenomena requires to deal with robust numerical tools in order to handle realistic scales in terms of energy, characteristic lengths and Mach number that cannot be easily reproduced by means of laboratory experiments. In this paper, we present the 2D numerical code HADES for the simulation of realistic astrophysical phenomena in various contexts, first taking into account radiative losses. The version of HADES including a multigroup modeling of radiative transfer will be presented in a forthcoming study. Validation of HADES is performed using several benchmark tests and some realistic applications are discussed. Optically thin radiative loss is modeled by a cooling function in the conservation law of energy. Numerical methods involve the MUSCL-Hancock finite volume scheme as well as HLLC and HLLE Riemann solvers, coupled with a second-order ODE solver by means of Strang splitting algorithm that handles source terms arising from geometrical or radiative contributions, for cartesian or axisymmetric configurations. A good agreement has been observed for all benchmark tests, either in hydrodynamic cases or in radiative cases. Furthermore, an overview of the main astrophysical studies driven with this code is proposed. First, simulations of radiative shocks in accretion columns and supernova remnant dynamics at large timescales including Vishniac instability have improved the understanding of these phenomena. Finally, astrophysical jets are investigated and the influence of the cooling effect on the jet morphology is numerically demonstrated. It is also found that periodic source enables to recover pulsating jets that mimic the structure of Herbig-Haro objects. HADES code has revealed its robustness, especially for the wall-shock test and for the so-called implosion test which turns out to be a severe one since the hydrodynamic variables are self-similar and become infinite at finite time. The simulations have proved the efficiency of

  9. Plasma lasers (a strong source of coherent radiation in astrophysics)

    Science.gov (United States)

    Papadopoulos, K.

    1981-01-01

    The generation of electromagnetic radiation from the free energy available in electron streams is discussed. The fundamental principles involved in a particular class of coherent plasma radiation sources, i.e., plasma lasers, are reviewed, focusing on three wave coupling, nonlinear parametric instabilities, and negative energy waves. The simplest case of plasma lasers, that of an unmagnetized plasma containing a finite level of density fluctuations and electrons streaming with respect to the ions, is dealt with. A much more complicated application of plasma lasers to the case of auroral kilometric radiation is then examined. The concept of free electron lasers, including the role of relativistic scattering, is elucidated. Important problems involving the escape of the excited radiation from its generation region, effects due to plasma shielding and nonlinear limits, are brought out.

  10. Bacterial inactivation by means of ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Chang, M.S.; Chen, L.H.; Fu, Y.K.

    1984-11-01

    Spores of Bacillus subtillis and Escherichia coli are the most common air-borne bacteria. B. subtilis is radiation resistant and is commonly used as the test strain for routine control of heat sterilization. A study of surviving fractions of spores of B. subtilis, E. coli, and Streptococcus faecium A/sub 2/l irradiated by /sup 60/Co gamma-rays was carried out to determine the suitable dose for medical sterilization by irradiation. 8 refs., 7 figs., 6 tabs.

  11. Pair production and ionizing radiation from superconductors

    OpenAIRE

    Hirsch, J. E.

    2005-01-01

    We show that an alternative theory of superconductivity recently proposed (theory of hole superconductivity) leads to the surprising consequence that real electron-positron pair production will occur for superconductors larger than a critical size. High frequency radiation with frequencies up to $0.511MeV/\\hbar$ is predicted to be emitted from superconductors out of equilibrium. Attention to the possibility of harmful consequences is called for.

  12. Building Protection Against External Ionizing Fallout Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Dillon, Michael B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Homann, Steven G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-12-01

    A nuclear explosion has the potential to injure or kill tens to hundreds of thousands of people through exposure to fallout (external gamma) radiation. Existing buildings can protect their occupants (reducing external radiation exposures) by placing material and distance between fallout particles and indoor individuals. This protection is not well captured in current fallout risk assessment models and so the US Department of Defense is implementing the Regional Shelter Analysis methodology to improve the ability of the Hazard Prediction and Assessment Capability (HPAC) model to account for building protection. This report supports the HPAC improvement effort by identifying a set of building attributes (next page) that, when collectively specified, are sufficient to calculate reasonably accurate, i.e., within a factor of 2, fallout shelter quality estimates for many individual buildings. The set of building attributes were determined by first identifying the key physics controlling building protection from fallout radiation and then assessing which building attributes are relevant to the identified physics. This approach was evaluated by developing a screening model (PFscreen) based on the identified physics and comparing the screening model results against the set of existing independent experimental, theoretical, and modeled building protection estimates. In the interests of transparency, we have developed a benchmark dataset containing (a) most of the relevant primary experimental data published by prior generations of fallout protection scientists as well as (b) the screening model results.

  13. 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.)

  14. Atmospheric Ionizing Radiation (AIR) ER-2 Preflight Analysis

    Science.gov (United States)

    Tai, Hsiang; Wilson, John W.; Maiden, D. L.

    1998-01-01

    Atmospheric ionizing radiation (AIR) produces chemically active radicals in biological tissues that alter the cell function or result in cell death. The AIR ER-2 flight measurements will enable scientists to study the radiation risk associated with the high-altitude operation of a commercial supersonic transport. The ER-2 radiation measurement flights will follow predetermined, carefully chosen courses to provide an appropriate database matrix which will enable the evaluation of predictive modeling techniques. Explicit scientific results such as dose rate, dose equivalent rate, magnetic cutoff, neutron flux, and air ionization rate associated with those flights are predicted by using the AIR model. Through these flight experiments, we will further increase our knowledge and understanding of the AIR environment and our ability to assess the risk from the associated hazard.

  15. NIF Laboratory Astrophysics Experiments Investigating The Effects Of A Radiative Shock On Hydrodynamic Instabilities

    Science.gov (United States)

    Kuranz, Carolyn C.; Drake, R. P.; Huntington, C. M.; Klein, S. R.; Trantham, M. R.; Park, H. S.; Remington, B. A.; Miles, A. R.; Raman, K.; Kline, J. L.; Plewa, T.

    2012-05-01

    This paper will describe ongoing laboratory astrophysics experiments at the National Ignition Facility (NIF) relevant to the complex radiation hydrodynamics that occurs in red supergiant, and core-collapse supernovae. Experiments on NIF can deliver 300 eV radiative heating that can be utilized uniquely access the regime in which radiation affects the development of hydrodynamic instabilities within an evolving object. This is relevant to the dynamics that occur during the core-collapse explosions of red supergiant stars. These stars have dense circumstellar plasma, producing a strongly radiative shock whose radiation interacts with the hydrodynamic structures produced by instabilities during the explosion. While published astrophysical simulations have not included complex, multidimensional radiation hydrodynamics, such effects are very physical and expected to affect the evolution of early stages of astrophysical objects described above. This presentation will include a summary of the two test shots that we have performed on NIF, including a 0.7 scale, gas-filled hohlraum test shot, and a description of the integrated physics shots scheduled at the facility. 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 , the Lawrence Livermore National Security, LLC, under Contract No. DE-AC52-07NA27344 and Predictive Sciences Academic Alliances Program in NNSA-ASC via grant DEFC52- 08NA28616.

  16. 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.).

  17. Collisional-radiative nonequilibrium in partially ionized atomic nitrogen

    Science.gov (United States)

    Kunc, J. A.; Soon, W. H.

    1989-01-01

    A nonlinear collisional-radiative model for determination of nonequilibrium production of electrons, excited atoms, and bound-bound, dielectronic and continuum line intensities in stationary partially ionized atomic nitrogen is presented. Populations of 14 atomic levels and line intensities are calculated in plasma with T(e) = 8000-15,000 K and N(t) = 10 to the 12th - 10 to the 18th/cu cm. Transport of radiation is included by coupling the rate equations of production of the electrons and excited atoms with the radiation escape factors, which are not constant but depend on plasma conditions.

  18. 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...

  19. Ionizing radiation regulations and the dental practitioner: 1. The nature of ionizing radiation and its use in dentistry.

    Science.gov (United States)

    Rout, John; Brown, Jackie

    2012-04-01

    Legislation governing the use of ionizing radiation in the workplace and in medical treatment first became law in 1985 and 1988, being superseded by the Ionizing Radiations Regulations 1999 (IRR99) and the Ionizing Radiation (Medical Exposure) Regulations 2000, (IR(ME)R 2000), respectively. This legislation ensures a safe environment in which to work and receive treatment and requires that those involved in the radiographic process must be appropriately trained for the type of radiographic practice they perform. A list of the topics required is detailed in Schedule 2 of IR(ME)R 2000 and is paraphrased in Table 1, with the extent and amount of knowledge required depending on the type of radiographic practice undertaken. Virtually all dental practitioners undertake radiography as part of their clinical practice. Legislation requires that users of radiation, including dentists and members of the dental team, understand the basic principles of radiation physics, hazards and protection, and are able to undertake dental radiography safely with the production of high quality, diagnostic images.

  20. 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.

  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. Statistical methods to evaluate thermoluminescence ionizing radiation dosimetry data

    Energy Technology Data Exchange (ETDEWEB)

    Segre, Nadia; Matoso, Erika; Fagundes, Rosane Correa, E-mail: nadia.segre@ctmsp.mar.mil.b [Centro Tecnologico da Marinha em Sao Paulo (CEA/CTMSP), Ipero, SP (Brazil). Centro Experimental Aramar

    2011-07-01

    Ionizing radiation levels, evaluated through the exposure of CaF{sub 2}:Dy thermoluminescence dosimeters (TLD- 200), have been monitored at Centro Experimental Aramar (CEA), located at Ipero in Sao Paulo state, Brazil, since 1991 resulting in a large amount of measurements until 2009 (more than 2,000). The data amount associated with measurements dispersion, since every process has deviation, reinforces the utilization of statistical tools to evaluate the results, procedure also imposed by the Brazilian Standard CNEN-NN-3.01/PR- 3.01-008 which regulates the radiometric environmental monitoring. Thermoluminescence ionizing radiation dosimetry data are statistically compared in order to evaluate potential CEA's activities environmental impact. The statistical tools discussed in this work are box plots, control charts and analysis of variance. (author)

  3. 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....

  4. Stimulation of the corneal blinking reflex by ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Tobias, C.; Luce, J.; Yanni, N.; Brustad, T.; Lyman, J.; Kimura, S.

    1961-05-04

    Accelerated alpha particles from the Berkeley heavy-ion linear accelerator were used in a series of experiments designed to elucidate the conditions by which radiation can stimulate or modify nerve action in mammals. Single millisecond pulses in excess of 40,000 radsor pulse trains of less than 1 sec duration elicited the corneal blinking reflex when delivered to the cornea of unanesthetized rabbits. The lowest threshold dose was observed when the Bragg ionization peak was placed at 140 {mu} depth.

  5. 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.)

  6. 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. Published by Elsevier Ltd.

  7. 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.

  8. 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.

  9. The Enceladus Ionizing Radiation Environment: Implications for Biomolecules

    Science.gov (United States)

    Teodoro, L. A.; Elphic, R. C.; Davila, A. F.; McKay, C.; Dartnell, L.

    2016-12-01

    Enceladus' subsurface ocean is a possible abode for life, but it is inaccessible with current technology. However, icy particles and vapor are being expelled into space through surface fractures known as Tiger Stripes, forming a large plume centered in the South Polar Terrains. Direct chemical analyses by Cassini have revealed salts and organic compounds in a significant fraction of plume particles, which suggests that the subsurface ocean is the main source of materials in the plume (i.e. frozen ocean spray). While smaller icy particles in the plume reach escape velocity and feed Saturn's E-ring, larger particles fall back on the moon's surface, where they accumulate as icy mantling deposits at practically all latitudes. The organic content of these fall-out materials could be of great astrobiological relevance. Galactic Cosmic Rays (GCRs) that strike both Enceladus' surface and the lofted icy particles produce ionizing radiation in the form of high-energy electrons, protons, gamma rays, neutrons and muons. An additional source of ionizing radiation is the population of energetic charged particles in Saturn's magnetosphere. The effects of ionizing radiation in matter always involve the destruction of chemical bonds and the creation of free radicals. Both affect organic matter, and can damage or destroy biomarkers over time. Using ionizing radiation transport codes, we recreated the radiation environment on the surface of Enceladus, and evaluated its possible effects on organic matter (including biomarkers) in the icy mantling deposits. Here, we present full Monte-Carlo simulations of the nuclear reactions induced by the GCRs hitting Enceladus's surface using a code based on the GEANT-4 toolkit for the transport of particles. To model the GCR primary spectra for Z= 1-26 (protons to iron nuclei) we assumed the CREAME96 model under solar minimum, modified to take into account Enceladus' location. We considered bulk compositions of: i) pure water ice, ii) water ice

  10. 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)

  11. L-shell radiative transition rates by selective synchrotron ionization

    Energy Technology Data Exchange (ETDEWEB)

    Bonetto, R D [Centro de Investigacion y Desarrollo en Ciencias Aplicadas Dr. Jorge J. Ronco, CONICET-UNLP, Calle 47 No. 257-Cc 59 (1900) La Plata (Argentina); Carreras, A C [Facultad de Matematica, AstronomIa y FIsica, Universidad Nacional de Cordoba, Ciudad Universitaria (5000) Cordoba (Argentina); Trincavelli, J [Facultad de Matematica, AstronomIa y FIsica, Universidad Nacional de Cordoba, Ciudad Universitaria (5000) Cordoba (Argentina); Castellano, G [Facultad de Matematica, AstronomIa y FIsica, Universidad Nacional de Cordoba, Ciudad Universitaria (5000) Cordoba (Argentina)

    2004-04-14

    Relative L-shell radiative transition rates were obtained for a number of decays in Gd, Dy, Er, Yb, Hf, Ta and Re by means of a method for refining atomic and experimental parameters involved in the spectral analysis of x-ray irradiated samples. For this purpose, pure samples were bombarded with monochromatic synchrotron radiation tuning the incident x-ray energy in order to allow selective ionization of the different atomic shells. The results presented are compared to experimental and theoretical values published by other authors. A good general agreement was found and some particular discrepancies are discussed.

  12. 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.

  13. 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.

  14. 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.

  15. Perspectives on Gravity-Induced Radiative Processes in Astrophysics

    Directory of Open Access Journals (Sweden)

    Giorgio Papini

    2015-04-01

    Full Text Available 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.

  16. 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.

  17. 21 CFR 579.22 - Ionizing radiation for treatment of animal diets.

    Science.gov (United States)

    2010-04-01

    ..., AND HANDLING OF ANIMAL FEED AND PET FOOD Radiation and Radiation Sources § 579.22 Ionizing radiation... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ionizing radiation for treatment of animal diets. 579.22 Section 579.22 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN...

  18. The effects of ionizing radiation on aquatic organisms

    Energy Technology Data Exchange (ETDEWEB)

    Templeton, W.L.; Blaylock, B.G.

    1990-09-01

    Scientific Committee {number sign}64-6 of the National Council on Radiation Protection (NCRP) of the United States has recently completed a review of the literature on the effects of ionizing radiation on aquatic organisms (NCRP 1990). In this report, the NCRP provides guidance for a dose rate below which deleterious effects to aquatic organisms are acceptably low; reviews a series of simple dosimetric models that can be applied to demonstrate compliance with such a dose rate; provides examples of the application of the models to contaminated aquatic environments; and evaluates the validity of the statement of the International Commission on Radiation Protection (ICRP 1977) that if man is adequately protected then other living things are also likely to be sufficiently protected.'' 6 refs.

  19. The pathology of ionizing radiation as defined by morphologic patterns

    Energy Technology Data Exchange (ETDEWEB)

    Fajardo, Luis Felipe [Stanford Univ. School of Medicine and Veterans Affairs Health Care System, Palo Alto, CA (United States)

    2005-02-01

    This article presents a brief description of the effects of ionizing radiation in human tissues, as seen by the Pathologist. The lesions that occur in multiple organ/tissues will be discussed, dividing them into those that affect (a) the parenchyma or epithelia, (b) the stromal elements, and (c) the blood vessels. Since not all lesions fit into these patterns, the exceptions will be described as characteristic organ lesions. Unless specified otherwise the alterations presented are those that result from electromagnetic radiation (x-rays and gamma rays) as used for clinical radiation therapy. Most of the material presented will be delayed injury (i.e. months-to-years after exposure). The epithelial/parenchymal lesions include atrophy, necrosis, metaplasia, cellular atypia, dysplasia, and neoplasia. The common stromal lesions--the best recognized by pathologists--include fibrosis, fibrinous exudates, necrosis (with a paucity of cellular inflammatory exudates), and atypical fibroblasts. The vascular lesions are quite consistent: most often they affect the microvessels (capillaries, sinusoids) producing lethal and sublethal damage to the endothelial cells, with capillary rupture or thrombosis. Medium-size vessels show neointimal proliferation, fibrinoid necrosis, thrombosis, or acute arteritis. Damage in large vessels is less common; it occurs more in arteries than in veins and includes neointimal proliferation, atheromatosis, thrombosis and rupture (a dramatic complication). Some of the characteristic organ lesions are veno-occlusive liver disease, acute radiation pneumonitis, permanent bone marrow hypoplasia or aplasia, and colitis cystica profunda. Neoplasms are a well-recognized delayed complication of radiation and will not be described in detail. It is important to remember that there are no pathognomonic features of injuries produced by ionizing radiation. Nonetheless, although not specific individually, the combined features are characteristic enough to be

  20. 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.

  1. 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.

  2. 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.

  3. Radiation protection and dosimetry issues in the medical applications of ionizing radiation

    Science.gov (United States)

    Vaz, Pedro

    2014-11-01

    The technological advances that occurred during the last few decades paved the way to the dissemination of CT-based procedures in radiology, to an increasing number of procedures in interventional radiology and cardiology as well as to new techniques and hybrid modalities in nuclear medicine and in radiotherapy. These technological advances encompass the exposure of patients and medical staff to unprecedentedly high dose values that are a cause for concern due to the potential detrimental effects of ionizing radiation to the human health. As a consequence, new issues and challenges in radiological protection and dosimetry in the medical applications of ionizing radiation have emerged. The scientific knowledge of the radiosensitivity of individuals as a function of age, gender and other factors has also contributed to raising the awareness of scientists, medical staff, regulators, decision makers and other stakeholders (including the patients and the public) for the need to correctly and accurately assess the radiation induced long-term health effects after medical exposure. Pediatric exposures and their late effects became a cause of great concern. The scientific communities of experts involved in the study of the biological effects of ionizing radiation have made a strong case about the need to undertake low dose radiation research and the International System of Radiological Protection is being challenged to address and incorporate issues such as the individual sensitivities, the shape of dose-response relationship and tissue sensitivity for cancer and non-cancer effects. Some of the answers to the radiation protection and dosimetry issues and challenges in the medical applications of ionizing radiation lie in computational studies using Monte Carlo or hybrid methods to model and simulate particle transport in the organs and tissues of the human body. The development of sophisticated Monte Carlo computer programs and voxel phantoms paves the way to an accurate

  4. Estimating nurses' exposures to ionizing radiation: the elusive gold standard.

    Science.gov (United States)

    Teschke, Kay; Chow, Yat; Chung, Joanna; Ratner, Pamela; Spinelli, John; Le, Nhu; Ward, Helen

    2008-02-01

    This study assessed ionizing radiation exposure in 58,125 registered nurses in British Columbia, Canada, for a cohort study of cancer morbidity and mortality. Two methods were used: (1) a survey of nurses in more than 100 acute care hospitals and health care centers; (2) and monitoring data reported to the National Dose Registry of Health Canada, considered the gold standard. The mean exposure of cohort nurses monitored during the study period from 1974 to 2000 was 0.27 milliSieverts (7028 person-years of monitoring). Of 609,809 person-years in the cohort, 554,595 (90.9%) were identified as unexposed by both exposure assessment methods. Despite crude agreement of 91% between the methods, weighted kappa for agreement beyond chance was only 0.045, and the sensitivity of the survey method to capture National Dose Registry monitored person-years was only 0.085 (specificity = 0.97). The survey missed exposures outside the acute care setting. The National Dose Registry also missed potential exposures, especially among hospital emergency department and pediatric staff nurses. It was unlikely that either method estimated nurses' true exposures to ionizing radiation with good sensitivity and specificity. The difficulty in exposure assessment likely arises because fewer than 10% of registered nurses are exposed to ionizing radiation, yet the settings in which they are exposed vary tremendously. This means that careful hazard assessment is required to ensure that monitoring is complete where exposures are probable, without incurring the excess costs and lack of specificity of including the unexposed.

  5. 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.

  6. Determination of radiative capture cross-section for astrophysics from transfer reaction using radioactive ion beams

    CERN Document Server

    Beaumel, D

    2002-01-01

    Thermonuclear reactions are a source of stellar energy and play a crucial role for the nucleosynthesis in astrophysical sites. Among these reactions, the radiative capture process defined as: x + A -> B + gamma is a key reaction involved in all the basic astrophysical processes over the nuclear chart. In the case of the capture of charged particles like (p,gamma) reactions, cross-sections are strongly weakened due to the low incident energies as compared to the Coulomb barrier. Their measurement in laboratories is even more complicate when the capturing nucleus is radioactive, difficult or even impossible to be used as a target. Such radioactive nuclei are involved essentially in 'explosive' environments where capture reactions are fast enough to compete with the beta-decay process. Even in non-explosive situations, unstable nuclei are sometimes important as we shall see for the hydrogen burning in the sun. To circumvent the difficulties of direct measurements with radioactive nuclei, indirect methods have be...

  7. Ionizing Radiation Exposure and Basal Cell Carcinoma Pathogenesis

    Science.gov (United States)

    Li, Changzhao; Athar, Mohammad

    2016-01-01

    This commentary summarizes studies showing risk of basal cell carcinoma (BCC) development in relationship to environmental, occupational and therapeutic exposure to ionizing radiation (IR). BCC, the most common type of human cancer, is driven by the aberrant activation of hedgehog (Hh) signaling. Ptch, a tumor suppressor gene of Hh signaling pathway, and Smoothened play a key role in the development of radiation-induced BCCs in animal models. Epidemiological studies provide evidence that humans exposed to radiation as observed among the long-term, large scale cohorts of atomic bomb survivors, bone marrow transplant recipients, patients with tinea capitis and radiologic workers enhances risk of BCCs. Overall, this risk is higher in Caucasians than other races. People who were exposed early in life develop more BCCs. The enhanced IR correlation with BCC and not other common cutaneous malignancies is intriguing. The mechanism underlying these observations remains undefined. Understanding interactions between radiation-induced signaling pathways and those which drive BCC development may be important in unraveling the mechanism associated with this enhanced risk. Recent studies showed that Vismodegib, a Smoothened inhibitor, is effective in treating radiation-induced BCCs in humans, suggesting that common strategies are required for the intervention of BCCs development irrespective of their etiology. PMID:26930381

  8. Ionizing and Nonionizing Radiation Protection. Module SH-35. Safety and Health.

    Science.gov (United States)

    Center for Occupational Research and Development, Inc., Waco, TX.

    This student module on ionizing and nonionizing radiation protection is one of 50 modules concerned with job safety and health. This module describes various types of ionizing and nonionizing radiation, and the situations in the workplace where potential hazards from radiation may exist. Following the introduction, 13 objectives (each keyed to a…

  9. Ionizing radiation applications for a sustainable environment: food preservation processing by gamma radiation

    OpenAIRE

    Antonio, Amilcar L.; Bento, Albino; Ferreira, Isabel C.F.R.; Cabo Verde, Sandra; Quintana, Begoña

    2014-01-01

    The use of ionizing gamma radiation is regulated and authorized by international organizations (EU, EFSA, IAEA, FAO, WHO) for industrial radiation processing of several products: medical devices sterilization, materials modification, cultural heritage preservation and food decontamination. Due to the wrong association of irradiated food with radioactive food, several obstacles have to be overcome in order to promote the civil use of radioisotopes for food irradiation, as a safe and useful app...

  10. 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)

  11. Proteomic Analysis of Low Dose Arsenic and Ionizing Radiation Exposure on Keratinocytes

    OpenAIRE

    Berglund, Susanne R.; Santana, Alison R.; Li, Dan; Rice, Robert H.; Rocke, David M; Goldberg, Zelanna

    2009-01-01

    Human exposure to arsenic and ionizing radiation occur environmentally at low levels. While the human health effects of arsenic and ionizing radiation have been examined separately, there is little information regarding their combined effects at doses approaching environmental levels. Arsenic toxicity may be affected by concurrent ionizing radiation especially given their known individual carcinogenic actions at higher doses. We found that keratinocytes responded to either low dose arsenic an...

  12. 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.

  13. Aberrations of Genetic Material as Biomarkers of Ionizing Radiation Effects

    Energy Technology Data Exchange (ETDEWEB)

    Milacic, S.

    2004-07-01

    Ionizing radiation is the most powerful mutagen in environmental and working conditions. The result of genotoxic effect of radiation is the development of chromosome aberrations. The structural chromosome aberrations in peripheral blood lymphocytes are dicentric, ring, acentric fragment. The observation of chromosome aberration frequency in lymphocyte karyotype is the conclusive method to assess the absorbed dose of ionizing radiation. Our study compared the incidence of chromosome aberrations in occupationally exposed healthy medical workers and in non-exposed healthy population. We analyzed the effect of working place, dose by thermo luminescence personal dosimeter (TLD), duration of occupational exposure (DOE) and age to the sum of aberrant cells and aberrations. four-year study included 462 subjects, mean-aged 42.3 years, who were occupational exposed to ionizing radiation and 95 subjects, mean-aged 35,2 years, who were not exposed to ionizing radiation, during the same time period and from the same territory. All of them possess thermo luminescence personal dosimeter (TLD) which is read by scanner for thermo luminescence dosimeters. Modified Moorheard's micro method for peripheral blood lymphocytes and conventional cytogenetic technique of chromosome aberration analysis were used for analysis of chromosome aberrations. Stained preparations (Giemsa) are observed in immersion by light microscope. The karyotype of 200 lymphocytes in metaphase is analyzed the most characteristic aberration: dicentric, then the ring and acentric fragments. The increased incidence of chromosome aberrations was found to tbe 21.6% in the exposed group and 2.1% in the controls, while the findings within the limits (non-specific chromosome lesions-gaps breaks, elongations, and exchanges) were equal in both groups (22%). Among occupationally exposed medical workers, the highest incidence was found in nuclear medicine workers (42.6%), then in orthopedists (27.08%). There is highly

  14. 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.

  15. Radiation sterilization of medical devices. Effects of ionizing radiation on ultra-high molecular-weight polyethylene

    Science.gov (United States)

    Buchalla, R.; Schüttler, C.; Bögl, K. W.

    1995-02-01

    Sterilization by ionizing radiation has become, next to ethylene oxide treament, the most important "cold" sterilization process for medical devices made from plastics. The effects of ionizing radiation on the most important polymer for medical devices, ultra-high molecular-weight polyethylene, are briefly described in this review.

  16. Ionizing radiation damage to cells: effects of cell cycle redistribution.

    Science.gov (United States)

    Chen, P L; Brenner, D J; Sachs, R K

    1995-04-01

    If a population of cycling cells is exposed to a fixed dose of ionizing radiation delivered over time T, it is sometimes observed that increasing T increases the amount of cell killing. This is essentially because at first the radiation preferentially kills cells in a sensitive portion of the cycle and the surviving, more resistant cells then have time to reach more sensitive stages. We refer to this effect as population resensitization, caused by redistribution within the cell cycle. We investigate the effect theoretically by employing the McKendrick-von Foerster equation for age-structured proliferating cell populations, generalized by introducing a radiation damage term. Within our formalism, we show that population resensitization occurs whenever: (a) prior to irradiation the cell population has the stable age-distribution approached asymptotically by an unirradiated population, and (b) T is sufficiently small. Examples and other cases are outlined. The methods of Volterra integral equations, renewal theory, and positive semigroup theory are applied. The effect of varying T is evaluated by considering the ultimate amplitude of the stable age-distribution population at times much greater than both the irradiation duration and the average cell-cycle time. The main biological limitations of the formalism are the following: considering only radiation damage which is not subject to enzymatic repair or quadratic misrepair, using an overly naive method of ensuring loss of cell cycle synchrony, neglecting nonlinear effects such as density inhibition of growth, and neglecting radiatively induced perturbations of the cell cycle. Possible methods for removing these limitations are briefly discussed.

  17. 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.

  18. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Pavoni, Juliana F.; Baffa, Oswaldo, E-mail: baffa@usp.br [Departamento de Física e Matemática, FFCLRP, Universidade de São Paulo, Av. Bandeirantes 3900, 14040-901, Monte Alegre, Ribeirão Preto, SP - Brazil (Brazil); Neves-Junior, Wellington F. P. [Hospital Sírio Libanês, R. Dona Adma Jafet 91, 01308-000, Bela Vista, São Paulo, SP – Brazil (Brazil)

    2016-07-07

    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.

  20. Extreme resistance of bdelloid rotifers to ionizing radiation.

    Science.gov (United States)

    Gladyshev, Eugene; Meselson, Matthew

    2008-04-01

    Rotifers of class Bdelloidea are common invertebrate animals with highly unusual characteristics, including apparently obligate asexuality, the ability to resume reproduction after desiccation at any life stage, and a paucity of transposable genetic elements of types not prone to horizontal transmission. We find that bdelloids are also extraordinarily resistant to ionizing radiation (IR). Reproduction of the bdelloids Adineta vaga and Philodina roseola is much more resistant to IR than that of Euchlanis dilatata, a rotifer belonging to the desiccation-intolerant and facultatively sexual class Monogononta, and all other animals for which we have found relevant data. By analogy with the desiccation- and radiation-resistant bacterium Deinococcus radiodurans, we suggest that the extraordinary radiation resistance of bdelloid rotifers is a consequence of their evolutionary adaptation to survive episodes of desiccation encountered in their characteristic habitats and that the damage incurred in such episodes includes DNA breakage that is repaired upon rehydration. Such breakage and repair may have maintained bdelloid chromosomes as colinear pairs and kept the load of transposable genetic elements low and may also have contributed to the success of bdelloid rotifers in avoiding the early extinction suffered by most asexuals.

  1. Occupational exposure to ionizing radiation for crews of suborbital spacecraft : questions & answers.

    Science.gov (United States)

    2013-12-01

    Crewmembers on future suborbital commercial spaceflights will be occupationally exposed to ionizing radiation, principally from galactic cosmic radiation. On infrequent occasions, the sun or thunderstorms may also contribute significantly to the ioni...

  2. 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.

  3. 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...

  4. 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.)

  5. Some New Results in Astrophysical Problems of Nonlinear Theory of Radiative Transfer

    Science.gov (United States)

    Pikichyan, H. V.

    2017-07-01

    In the interpretation of the observed astrophysical spectra, a decisive role is related to nonlinear problems of radiative transfer, because the processes of multiple interactions of matter of cosmic medium with the exciting intense radiation ubiquitously occur in astrophysical objects, and in their vicinities. Whereas, the intensity of the exciting radiation changes the physical properties of the original medium, and itself was modified, simultaneously, in a self-consistent manner under its influence. In the present report, we show that the consistent application of the principle of invariance in the nonlinear problem of bilateral external illumination of a scattering/absorbing one-dimensional anisotropic medium of finite geometrical thickness allows for simplifications that were previously considered as a prerogative only of linear problems. The nonlinear problem is analyzed through the three methods of the principle of invariance: (i) an adding of layers, (ii) its limiting form, described by differential equations of invariant imbedding, and (iii) a transition to the, so-called, functional equations of the "Ambartsumyan's complete invariance". Thereby, as an alternative to the Boltzmann equation, a new type of equations, so-called "kinetic equations of equivalence", are obtained. By the introduction of new functions - the so-called "linear images" of solution of nonlinear problem of radiative transfer, the linear structure of the solution of the nonlinear problem under study is further revealed. Linear images allow to convert naturally the statistical characteristics of random walk of a "single quantum" or their "beam of unit intensity", as well as widely known "probabilistic interpretation of phenomena of transfer", to the field of nonlinear problems. The structure of the equations obtained for determination of linear images is typical of linear problems.

  6. Studies on the sterilization of pharmaceutical base materials with ionizing radiation and ethylene oxide.

    Science.gov (United States)

    Woźniak-Parnowska, W; Najer, A

    1978-01-01

    The use of ionizing radiation and ethylene oxide for the sterilization of pharmaceutical base materials of animal origin, used to produce organopreparations, was studied. The materials included liver extract, pancreas extract, dried thyroid and intrinsic factor. The effective sterilizing doses for the examined materials and dependence between effective ionizing radiation dose and primary contamination were determined.

  7. 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

  8. [Evaluation of exposure to ionizing radiation among gamma camera operators].

    Science.gov (United States)

    Domańska, Agnieszka Anna; Bieńkiewicz, Malgorzata; Olszewski, Jerzy

    2013-01-01

    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 Lódz, where thousands of different diagnostic procedures are performed yearly. 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. 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. 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.

  9. 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.

  10. 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.

  11. Neoplastic transformation of human thyroid epithelial cells by ionizing radiation

    Science.gov (United States)

    Herceg, Zdenko

    Neoplastic transformation of human thyroid epithelial cells has been investigated following exposure to ionizing radiation in vitro. The effects of radiation type, irradiation regime, and postirradiation passaging were examined using a human thyroid epithelial cell line, designated HToriS, which was previously immortalized with SV40 genome. Exponentially growing HToriS cells were irradiated with graded doses of 137 Cs gamma- and 238pu alpha-irradiation. Cells were irradiated with either a single or multiple doses of 0.5, 1, 2, 3, or 4 Gy gamma-radiation, or single doses of 0.125, 0.25, 0.5, 1, or 1.5 Gy gamma-radiation. Following passaging, the cells were transplanted into the athymic nude mice, and the animals were screened for tumour formation. Statistically significant increases in tumour incidence were obtained with both gamma- and alpha-irradiation and with both single and multiple irradiation regimes as compared with the un-irradiated group. Regardless of radiation type and or radiation regime there appears to be a trend, with increasing doses of radiation, in which tumour incidence increases and reaches a maximum, after which the tumour incidence decreases. Tumours were characterized by histopathological examination as undifferentiated carcinomas. Investigation of expression time following irradiation demonstrated that post-irradiation passaging, generally regarded as a critical step for expression of radiation-induced DNA damage, was not a prerequisite for the neoplastic conversion of irradiated cells with this system. Cell lines were established from the tumours and their identification and characterization carried out. All cell lines established were determined to be derived from the parent HTori3 cells by DNA fingerprinting, karyotype analysis, cytokeratin staining, and SV40 large T-antigen staining. Tumorigenicity of the cell lines was confirmed by retransplantation. Comparison of the morphology in vitro showed that the tumour cell lines retained the

  12. 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.

  13. Uses of ionizing radiation and medical-care-related problems

    Energy Technology Data Exchange (ETDEWEB)

    Smathers, J.B.

    1988-08-01

    The uses of ionizing radiation in medicine are currently undergoing changes due to at least four major influences: (1) the constantly changing public perception of the hazards of radiation, (2) continuing technical innovation and development in equipment, (3) the imposition of diagnosis-related group funding by government health-care funding agencies, and (4) an increase in the average age of the U.S. population. The combined effect of these influences will probably result in a major increase in biplanar fluoroscopic examinations to support nonsurgical approaches such as percutaneous transluminal coronary angioplasty, percutaneous transluminal neuroembolism, and lithotripsy (the fracturing of kidney stones). As some of these examinations can result in 1.5 h of fluoroscopy, major doses to the patient and to the clinical staff can be expected. In addition, improved diagnostic techniques, such as using positron emission tomography (a combination of biochemistry and positron-emitting isotopes), can be expected to increase the number of small cyclotrons installed in medical centers. Counteracting these increases in radiation exposure is the development of digital radiography, which generally results in a lowering of the dose per diagnostic procedure. In the realm of therapeutic uses, one can expect higher-energy treatment accelerators, more patients being released from the hospital on therapeutic doses of isotopes, and a potential acceptance of neutron therapy as a cancer treatment modality. The latter treatment may take the form of boron capture therapy, 252Cf implant therapy, or external beam therapy using high-energy cyclotrons and the p,Be or the d,Be reaction to create the neutrons.

  14. Hybrid polygon and hydrodynamic nebula modeling with multi-waveband radiation transfer in astrophysics

    Science.gov (United States)

    Steffen, W.; Koning, N.

    2017-07-01

    We demonstrate the potential for research and outreach of mixed polygon and hydrodynamic modeling and multi-waveband rendering in the interactive 3-D astrophysical virtual laboratory Shape. In 3-D special effects and animation software for the mass media, computer graphics techniques that mix polygon and numerical hydrodynamics have become common place. In astrophysics, however, interactive modeling with polygon structures has only become available with the software Shape. Numerical hydrodynamic simulations and their visualization are usually separate, while in Shape it is integrated with the polygon modeling approach that requires no programming by the user. With two generic examples, we demonstrate that research and outreach modeling can be achieved with techniques similar to those used in the media industry with the added capability for physical rendering at any wavelength band, yielding more realistic radiation modeling. Furthermore, we show how the hydrodynamics and the polygon mesh modeling can be mixed to achieve results that are superior to those obtained using either one of these modeling techniques alone.

  15. Quantitative estimation of UV light dose concomitant to irradiation with ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Petin, Vladislav G.; Morozov, Ivan I. [Biophysical Laboratory, Medical Radiological Research Center, 249036 Obninsk, Kaluga Region (Russian Federation); Kim, Jin Kyu, E-mail: jkkim@kaeri.re.k [Korea Atomic Energy Research Institute, Advanced Radiation Technology Institute, Jeongeup 580-185 (Korea, Republic of); Semkina, Maria A. [Biophysical Laboratory, Medical Radiological Research Center, 249036 Obninsk, Kaluga Region (Russian Federation)

    2011-01-15

    A simple mathematical model for biological estimation of UV light dose concomitant to ionizing radiation was suggested. This approach was applied to determine the dependency of equivalent UV light dose accompanied by 100 Gy of ionizing radiation on energy of sparsely ionizing radiation and on volume of the exposed cell suspension. It was revealed that the relative excitation contribution to the total lethal effect and the value of UV dose was greatly increased with an increase in energy of ionizing radiation and volume of irradiated suspensions. It is concluded that these observations are in agreement with the supposition that Cerenkov emission is responsible for the production of UV light damage and the phenomenon of photoreactivation observed after ionizing exposure of bacterial and yeast cells hypersensitive to UV light. A possible synergistic interaction of the damages produced by ionizations and excitations as well as a probable participation of UV component of ionizing radiation in the mechanism of hormesis and adaptive response observed after ionizing radiation exposure is discussed.

  16. STUDYING OF POSSIBILITY A WILLOW WHITE (SALIX ALBA L.) BRANCHES STERILIZATION BY IONIZING RADIATION

    OpenAIRE

    Ольга Олеговна Фролова; Анна Степановна Саушкина; Майя Викторовна Мазурина; Ася Юрьевна Айрапетова; Евгения Геннадьевна Компанцева; Евгения Владимировна Компанцева

    2014-01-01

    There was determined a quantity of microorganisms in Salix alba L. branches specimens after processing by ionizing radiation (0,25–5 kGy). The powder of S. alba branches conform to recommended requirements for a standard "Microbiological purity" after processing by the minimal radiation dose, that’s why offered method of sterilization is effective. Ionizing radiation is acceptable for S. alba branches processing, because it doesn't influence significantly on the structure and the quantity of ...

  17. Evaluation of low dose ionizing radiation effect on some blood components in animal model

    OpenAIRE

    H. El-Shanshoury; G. El-Shanshoury; A. Abaza

    2016-01-01

    Exposure to ionizing radiation is known to have lethal effects in blood cells. It is predicted that an individual may spend days, weeks or even months in a radiation field without becoming alarmed. The study aimed to discuss the evaluation of low dose ionizing radiation (IR) effect on some blood components in animal model. Hematological parameters were determined for 110 animal rats (divided into 8 groups) pre- and post-irradiation. An attempt to explain the blood changes resulting from both ...

  18. Reductions in Calcium Uptake Induced in Rat Brain Synaptosomes by Ionizing Radiation

    Science.gov (United States)

    1991-01-01

    located in the brain and heart using nimodipine and Reductions in Calcium Uptake Induced in Rat Brain Synapto- nifedipine (I1-13). Nimodipine binding...was also reduced by radiation exposure. Nimodipine binding to dihydropyridine (DHP) L-type calcium uptake after irradiation in wh31e-brain, cortical...resistant to the direct effects of MATERIALS AND METHODS ionizing radiation, exposure to ionizing radiation can have Materials. Bay K 8644 and nimodipine

  19. 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.

  20. Radiative Processes in Astrophysical Gases: From the Intergalactic and Interstellar Medium to Exoplanetary Atmospheres

    Science.gov (United States)

    Oklopi'c, Antonija

    2017-05-01

    This thesis presents theoretical investigations in three areas of astrophysics, all related to radiative processes and interactions between stellar radiation and gaseous media in the Universe, ranging from the intergalactic and interstellar medium to planetary atmospheres. Part I of the thesis consists of two independent investigations in which we study the effects of stellar feedback in high-redshift environments. The topic of Chapter 2 is the intergalactic medium (IGM) in the epoch just after the formation of the first stars in the Universe, but before the cosmic reionization was completed. This epoch is of great interest for the ongoing and future experiments aimed at observing the neutral IGM via the redshifted 21 cm line of hydrogen. We study the effects of resonant scattering of Lyman-α photons produced by early stars on the structure of temperature fluctuations in the IGM. In Chapter 3, we use cosmological hydrodynamic simulations of galaxy evolution to study the effects of stellar feedback on the clumpy structure of star-forming galaxies at i>zproject. Part II of the thesis is devoted to the effects of Raman scattering of stellar radiation in the atmospheres of extrasolar planets. Spectral signatures of Raman scattering imprinted in the geometric albedo spectrum of a gaseous planet carry information about the properties of the planet's atmosphere--its composition, temperature, and the radiation-penetration depth. In Chapter 5, we present the results of radiative transfer calculations including the treatment of Raman scattering for different types of planetary atmospheres and analyze the feasibility of detecting the spectral signatures of Raman scattering in nearby exoplanets. The structure and the intensity of Raman spectral features depends on both the atmospheric properties and the shape of the stellar spectrum irradiating the atmosphere. In Chapter 6, we analyze the diversity of Raman features in the geometric albedo spectra of planets hosted by

  1. 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.

  2. 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)

  3. Advanced water remediation from ofloxacin by ionizing radiation

    Science.gov (United States)

    Esposito, Biagio R.; Capobianco, Massimo L.; Martelli, Alessandro; Navacchia, Maria Luisa; Pretali, Luca; Saracino, Michela; Zanelli, Alberto; Emmi, Salvatore S.

    2017-12-01

    The performances of remediation processes initiated by ionizing radiation on ofloxacin are investigated in ambient conditions. The effectiveness of the decomposition of ofloxacin has been assessed both by γ-rays and electron beam in various aqueous solutions differentiated by the dissolved gases (Air or oxygen saturated) and H2O2. By HPLC it is shown that ofloxacin is removed according to a first order process vs. dose in any system. O2 accelerates the decomposition rate, while H2O2 does not seem to enhance any oxidation effect. The simultaneous oxidative-reductive treatment (no additive) demonstrated to have better mineralizing performances than the fully oxidative one (H2O2 present). Mineralization by γ results to be more efficient than by EB. The Total Organic Carbon decrease was investigated in dependence of dose and of the •OH production rate. The latter parameter was changed over 7 orders of magnitude by controlling dose rate and/or by adding H2O2. A steep increase of acidity remarks the phases of fluorine-carbon bond break.

  4. 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...

  5. Fluorescence caused by ionizing radiation from ball lightning: Observation and quantitative analysis

    Science.gov (United States)

    Stephan, Karl D.; Krajcik, Rozlyn; Martin, Rolf J.

    2016-10-01

    Ball lightning is a rare phenomenon, typically appearing as a glowing sphere associated with thunderstorms. In 2008 one of the authors witnessed a blue ball-lightning object hover in front of a glass window that appeared to glow yellow. Calibrated quantitative fluorometry measurements of the window show that the glow was probably due to fluorescence caused by ionizing radiation (UV or possibly X rays). Based on the measurements performed, estimates of the total ionizing-radiation power emitted by the object range upward from about 10 W. These are among the most reliable semi-quantitative measurements so far of ionizing-radiation output from a ball-lightning object.

  6. Ionizing radiation interactions with DNA: nanodosimetry; Ionisierende Strahlungswechselwirkung mit der DNS. Nanodosimetrie

    Energy Technology Data Exchange (ETDEWEB)

    Bug, Marion; Nettelbeck, Heidi [Physikalisch-Technische Bundesanstalt (PTB), Braunschweig (Germany). Arbeitsgruppe ' Biologische Wirksamkeit ionisierender Strahlung' ; Hilgers, Gerhard [Physikalisch-Technische Bundesanstalt (PTB), Braunschweig (Germany). Arbeitsgruppe ' Nanodosimetrie' ; Rabus, Hans [Physikalisch-Technische Bundesanstalt (PTB), Braunschweig (Germany). Fachbereich ' Grundlagen der Dosimetrie'

    2011-06-15

    The metrology of ionizing radiation is based on measuring values that are averaged over macroscopic volume elements, for instance the energy dose is defined as ratio of the energy deposited on the absorber and the absorber mass. For biological or medical radiation effects the stochastic nature of radiation interaction is of main importance, esp. the interaction of ionizing radiation with the DNA as the genetic information carrier. For radiotherapy and risk evaluation purposes a comprehensive system of radiation weighing factors and other characteristics, like radiation quality or relative biological efficacy was developed. The nanodosimetry is aimed to develop a metrological basis relying on physical characteristics of the microscopic structure of ionizing radiation tracks. The article includes the development of experimental nanodosimetric methods, the respective calibration techniques, Monte-Carlo simulation of the particle track microstructure and the correlation nanodosimetry and biological efficiency.

  7. 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.

  8. 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

  9. The Problem of the Harmlessness of Using Food Products Sterilized by Means of Ionizing Radiation: USSR

    National Research Council Canada - National Science Library

    Yegiazarov, G

    1960-01-01

    ...) radioactivity originated in the food products. It is known further that as a result of the action of ionizing radiation there appear undesirable secondary changes in the physico-chemical and organoleptic indices of the sterilized products...

  10. The bio markers of ionizing radiation; Los biomarcadores de las radaiciones ionizantes

    Energy Technology Data Exchange (ETDEWEB)

    Pernot, E.; Cardis, E.

    2011-07-01

    This article reviews bio markers currently used to study the biological effects of ionizing radiation and proposed a classification based on the time of onset of biological effects related to exposure time and persistence over time.

  11. How protective are the lead aprons we use against ionizing radiation?

    National Research Council Canada - National Science Library

    Orhan Oyar; Arzu Kislalioglu

      PURPOSE To evaluate, in terms of their protective features, the lead aprons used in areas working with ionizing radiation at a hospital by analyzing qualitative and quantitative aspects using a variety of methods...

  12. MDP: A Deinococcus Mn2+-Decapeptide Complex Protects Mice from Ionizing Radiation

    National Research Council Canada - National Science Library

    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 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...

  13. Self-Consistent Solution of Cosmological Radiation-Hydrodynamics and Chemical Ionization

    OpenAIRE

    Reynolds, Daniel R.; Hayes, John C.; Paschos, Pascal; Norman, Michael L.

    2009-01-01

    We consider a PDE system comprising compressible hydrodynamics, flux-limited diffusion radiation transport and chemical ionization kinetics in a cosmologically-expanding universe. Under an operator-split framework, the cosmological hydrodynamics equations are solved through the Piecewise Parabolic Method, as implemented in the Enzo community hydrodynamics code. The remainder of the model, including radiation transport, chemical ionization kinetics, and gas energy feedback, form a stiff couple...

  14. Detection and quantification of 8-hydroxydeoxyguanosine adducts in peripheral blood of people exposed to ionizing radiation.

    OpenAIRE

    Wilson, V L; Taffe, B G; Shields, P.G.; Povey, A C; Harris, C.C.

    1993-01-01

    Ionizing radiation produces a variety of damaging insults to nucleic acids, including the promutagenic lesion 8-hydroxydeoxyguanosine. In the present study, the 8-hydroxydeoxyguanosine content of peripheral blood leukocyte DNA isolated from individuals exposed to therapeutic doses of ionizing radiation was determined by a HPLC-coupled 32P-postlabeling assay. Peripheral blood leukocyte DNA from individuals irradiated with 180-200 cGy were observed to contain 2-4.5 times as much 8-hydroxydeoxyg...

  15. Recollections on Sixty Years of NBS Ionizing Radiation Programs for Energetic X Rays and Electrons1

    OpenAIRE

    Koch, H. William

    2006-01-01

    These recollections are on ionizing radiation programs at the National Bureau of Standards (NBS) that started in 1928 and ended in 1988 when NBS became the National Institute of Standards and Technology (NIST). The independent Council on Ionizing Radiation Measurements and Standards (CIRMS) was formed in 1992. This article focuses on how measurements and standards for x rays, gamma rays, and electrons with energies above 1 MeV began at NBS and how they progressed. It also suggests how the rad...

  16. Health risk to non-ionizing radiation by the telecommunications networks in Peru

    OpenAIRE

    Cruz, Víctor M.; Salud ambiental; Radiación no ionizante; Red de telecomunicaciones, Teléfono celular, Perú.

    2009-01-01

    We review the various studies on the potential impact of telecommunications networks on health, these studies relate to the possible health effects due to thermal effect of non-ionizing radiation produced greater increases in body temperature at 1 ºC. f urthermore, the studies were reviewed for assessment of exposure to non-ionizing radiation of telecommunications networks in Peru from 2000 to 2006 that include the measurement of more than 500 locations. The highest average levels of exposure...

  17. 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.

  18. Radioprotective Effect of Thymol Against Salivary Glands Dysfunction Induced by Ionizing Radiation in Rats.

    Science.gov (United States)

    Abedi, Seyed Mohammad; Yarmand, Fateme; Motallebnejad, Mina; Seyedmajidi, Maryam; Moslemi, Dariush; Bijani, Ali; Hosseinimehr, Seyed Jalal

    2016-01-01

    The aim of this study was to investigate the radioprotective effect of thymol as a natural product against salivary glands dysfunction induced by ionizing radiation in rats. The rats were treated with thymol at dose of 50 mg/Kg before exposure to ionizing radiation at dose 15 Gy. Salivary gland function was evaluated with radioisotope scintigraphy and then salivary gland to background counts ratio was calculated. Ionizing radiation caused significant salivary glands dysfunction at the 3th and the 70th days with reduction in radioactivity uptake in salivary glands. Ratios of salivary gland to background radioactivities were 2.0 ± 0.05, 1.58 ± 0.62 and 1.99 ± 0.07 at 3th days for control, radiation, and thymol plus radiation groups, respectively. Thymol significantly protected acute and chronic salivary gland dysfunction induced by ionizing radiation in the rats.This finding may have been a promising application of thymol for the protection of salivary glands dysfunction induced by ionizing irradiation in patients exposed to radiation in head and neck cancer therapy.

  19. Radiative Properties of Implosions of Stainless Steel Wire Arrays with Application to Astrophysics

    Science.gov (United States)

    Safronova, A. S.; Ouart, N. D.; Kantsyrev, V. L.; Esaulov, A. A.; Safronova, U. I.; Williamson, K. M.; Shrestha, I.; Coverdale, C. A.; Jones, B.; Deeney, C.

    2009-01-01

    Experiments with different stainless steel (SS) wire loads were performed on the 1 MA Zebra Z-pinch generator at University of Nevada, Reno. The wire array loads consisted of 7.6 μm SS wires and had 10 wires for the planar wire array with an interwire gap of 1 mm and 8 wires for the cylindrical wire array of a 16 mm diameter. In addition, a single-wire experiment with a 25 μm SS wire was carried out. The different wire loads were used to provide a broader spectrum of plasma conditions. Time-integrated and time-gated x-ray images, as well as time-integrated, spatially-resolved and spatially-integrated x-ray spectra, were collected and analyzed. Both K-shell and L-shell radiation were recorded using LiF and KAP crystal spectrometers, respectively. Non-LTE kinetic models of Fe and Ni are employed to derive plasma parameters. For axially resolved L-shell spectra, the resulting electron temperatures are between 230 and 300 eV (higher near the cathode) and electron densities vary from 1019 to 1020 cm-3 dependent on the load. The advantage of using Z-pinch plasmas for astrophysical applications is highlighted.

  20. Ionizing radiation measurements and assay of corresponding dose

    African Journals Online (AJOL)

    PUBLICATIONS1

    Nuclear Radiation Meters and Global Positioning System. The survey meters were held ... process release radiation to the environment. (IAEA, 2004). ..... Energy. DE-AC06-76RLO 1830. United Nations Scientific Committee on the. Effects of Atomic Radiation. (UNSCEAR). (2001). Hereditary effects of radiation. Report to the ...

  1. 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

  2. Radiation-induced bystander effect: The important part of ionizing radiation response. Potential clinical implications

    Directory of Open Access Journals (Sweden)

    Maria Wideł

    2009-08-01

    Full Text Available It has long been a central radiobiological dogma that the damaging effects of ionizing radiation, such as cell death, cytogenetic changes, apoptosis, mutagenesis, and carcinogenesis, are the results of the direct ionization of cell structures, particularly DNA, or indirect damage via water radiolysis products. However, several years ago attention turned to a third mechanism of radiation, termed the “bystander effect” or “radiation-induced bystander effect” (RIBE. This is induced by agents and signals emitted by directly irradiated cells and manifests as a lowering of survival, cytogenetic damage, apoptosis enhancement, and biochemical changes in neighboring non-irradiated cells. The bystander effect is mainly observed in in vitro experiments using very low doses of alpha particles (range; mGy, cGy, but also after conventional irradiation (X-rays, gamma rays at low as well as conventional doses. The mechanisms responsible for the bystander effect are complex and still poorly understood. It is believed that molecular signals released from irradiated cells induce different signaling ways in non-irradiated neighboring cells, leading to the observed events. The molecular signals may be transmitted through gap junction intercellular communication and through a medium transfer mechanism. The nature of these transmitted factors are diverse, and still not defi nitely established. It seems that RIBE may have important clinical implications for health risk associated with radiation exposure. Potentially, this effectmay have important implications in the creation of whole-body or localized side effects in tissues beyond the irradiation fi eld and also in low-dose radiological and radioisotope diagnostics. Factors emitted by irradiated cells may result in the risk of genetic instability, mutations, and second primary cancer induction. They might also have their own part in inducing and extending post-radiation side effects in normal tissue. The

  3. The Measurement of Radiative Lifetimes Using Laser-Induced Fluorescence: Experimental Review and Astrophysical Application

    Energy Technology Data Exchange (ETDEWEB)

    Hartog, E.A. den; Lawler, J.E. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Physics; Sneden, C. [Univ. of Texas, Austin, TX (United States). Dept. of Astronomy and McDonald Observatory

    2005-10-01

    One of the standard methods for determining atomic transition probabilities is to combine branching fractions measured using Fourier-transform spectrometry with radiative lifetimes measurements using laser-induced fluorescence (LIF). This combination of techniques provides an efficient method for measuring large sets of accurate, absolute transition probabilities. The radiative lifetimes, which provide the overall scaling for the transition probabilities, can be measured routinely to {+-}5% accuracy using time-resolved LIF. Although the time-resolved LIF technique we use does not achieve the accuracy of fast-beam LIF, the time-resolved technique does enable us to make measurements at a far greater rate (hundreds of level lifetimes per year). Care must be taken, however, to understand and control the systematic effects in time-resolved LIF measurements to maintain {+-}5% accuracy over a wide dynamic range and hundreds of lifetime measurements. Over the last 25 years, we have measured lifetimes for 47 spectra using time resolved LIF. Our atomic beam source can produce a slow beam of neutral and singly ionized atoms of nearly any element. Lifetimes from 2 ns to {approx}2{mu}s can be measured for energy levels ranging from 15,000 to {approx}60,000/cm. In this review we will describe our method of measuring radiative lifetimes with an emphasis on possible errors and techniques used for controlling them. The electronic bandwidth, linearity, and overall fidelity of the fast photomultiplier, cable connections, and transient waveform digitizer are concerns. Possible errors from atomic collisions, radiation trapping, Zeeman quantum beats, hyperfine quantum beats, atoms/ions escaping from the observation region before radiating, and from radiative cascade through lower levels must be understood and controlled. We will then present a recent example of the application of our transition probability data to abundance determinations in the sun and in metal-poor halo stars. Our

  4. 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.

  5. Basal DNA repair machinery is subject to positive selection in ionizing-radiation-resistant bacteria

    Directory of Open Access Journals (Sweden)

    Barkallah Insaf

    2008-06-01

    Full Text Available Abstract Background Ionizing-radiation-resistant bacteria (IRRB show a surprising capacity for adaptation to ionizing radiation and desiccation. Positive Darwinian selection is expected to play an important role in this trait, but no data are currently available regarding the role of positive adaptive selection in resistance to ionizing-radiation and tolerance of desiccation. We analyzed the four known genome sequences of IRRB (Deinococcus geothermalis, Deinococcus radiodurans, Kineococcus radiotolerans, and Rubrobacter xylanophilus to determine the role of positive Darwinian selection in the evolution of resistance to ionizing radiation and tolerance of desiccation. Results We used the programs MultiParanoid and DnaSP to deduce the sets of orthologs that potentially evolved due to positive Darwinian selection in IRRB. We find that positive selection targets 689 ortholog sets of IRRB. Among these, 58 ortholog sets are absent in ionizing-radiation-sensitive bacteria (IRSB: Escherichia coli and Thermus thermophilus. The most striking finding is that all basal DNA repair genes in IRRB, unlike many of their orthologs in IRSB, are subject to positive selection. Conclusion Our results provide the first in silico prediction of positively selected genes with potential roles in the molecular basis of resistance to γ-radiation and tolerance of desiccation in IRRB. Identification of these genes provides a basis for future experimental work aimed at understanding the metabolic networks in which they participate.

  6. Effects of Ionizing Radiation on Cellular Structures, Induced Instability, and Carcinogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Resat, Marianne S.; Arthurs, Benjamin J.; Estes, Brian J.; Morgan, William F.

    2006-03-01

    According to the American Cancer Society, the United States can expect 1,368,030 new cases of cancer in 2004 [1]. Among the many carcinogens Americans are exposed to, ionizing radiation will contribute to this statistic. Humans live in a radiation environment. Ionizing radiation is in the air we breathe, the earth we live on, and the food we eat. Man-made radiation adds to this naturally occurring radiation level thereby increasing the chance for human exposure. For many decades the scientific community, governmental regulatory bodies, and concerned citizens have struggled to estimate health risks associated with radiation exposures, particularly at low doses. While cancer induction is the primary concern and the most important somatic effect of exposure to ionizing radiation, potential health risks do not involve neoplastic diseases exclusively but also include somatic mutations that might contribute to birth defects and ocular maladies, and heritable mutations that might impact on disease risks in future generations. Consequently it is important we understand the effect of ionizingradiation on cellular structures and the subsequent long-term health risks associated with exposure to ionizing radiation.

  7. 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.

  8. EURADOS. A success story for European cooperation in the dosimetry of ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ruehm, Werner [Helmholtz Zentrum Muenchen, Neuherberg (Germany). German Research Center for Environmental Health (GMBH); Schuhmacher, Helmut [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany)

    2017-10-01

    EURADOS (European Radiation Dosimetry Group) is a European research platform aiming at the promotion of research and development and European cooperation in the field of the dosimetry of ionizing radiation (www.eurados.org). Initially founded in 1982, it was established in 2008 as a non-profit registered society under German law and is currently based in Neuherberg, Germany.

  9. 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.

  10. 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.

  11. Scattered ionizing radiations from low-energy focus plasma and ...

    Indian Academy of Sciences (India)

    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 ...

  12. Chemical inhibition of cell recovery after irradiation with sparsely and densely ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Evastratova, Ekaterina S.; Petin, Vladislav [A. Tsyb Medical Radiological Research Centre-branch of the National Medical Research Radiological Centre of the Ministry of Health of the Russian Federation, Obninsk (Russian Federation); Kim, Jin Hong; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Advanced Radiation Technology Institute (ARTI), Jeongeup (Korea, Republic of); Lim, Youg Khi [Dept. of Radiological Science, Gachon University, Incheon (Korea, Republic of)

    2017-02-15

    The dependence of cell survival on exposure dose and the duration of the liquid holding recovery (LHR) was obtained for diploid yeast cells irradiated with ionizing radiation of different linear energy transfer (LET) and recovering from radiation damage without and with various concentrations of cisplatin - the most widely used anticancer drug. The ability of yeast cells to recover from radiation damage was less effective after cell exposure to high-LET radiation, when cells were irradiated without drug. The increase in cisplatin concentration resulted in the disappearance of this difference whereas the fraction of irreversible damage was permanently enlarged independently of radiation quality. The probability of cell recovery was shown to be constant for various conditions of irradiation and recovery. A new mechanism of cisplatin action was suggested according with which the inhibition of cell recovery after exposure to ionizing radiations was completely explained by the production of irreversible damage.

  13. 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.

  14. 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.

  15. 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)

  16. [Investigation of non-ionizing radiation hazards from physiotherapy equipment in 16 medical institutions].

    Science.gov (United States)

    He, Jia-xi; Zhou, Wei; Qiu, Hai-li; Yang, Guang-tao

    2013-12-01

    To investigate the non-ionizing radiation hazards from physiotherapy equipment in medical institutions and to explore feasible control measures for occupational diseases. On-site measurement and assessment of ultra-high-frequency radiation, high-frequency electromagnetic field, microwave radiation, and laser radiation were carried out in 16 medical institutions using the methods in the Measurement of Physical Agents in Workplace (GBZ/T189-2007). All the investigated medical institutions failed to take effective protective measures against non-ionizing radiation. Of the 17 ultra-short wave therapy apparatus, 70.6%, 47.1%, and 17.64% had a safe intensity of ultra-high-frequency radiation on the head, chest, and abdomen, respectively. Of the 4 external high-frequency thermotherapy apparatus, 100%, 75%, and 75%had a safe intensity of high-frequency electromagnetic field on the head, chest, and abdomen, respectively. In addition, the intensities of microwave radiation and laser radiation produced by the 18 microwave therapy apparatus and 12 laser therapeutic apparatus met national health standards. There are non-ionizing radiation hazards from physiotherapy equipment in medical institutions, and effective prevention and control measures are necessary.

  17. 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.

  18. Modeling of ionizing radiation effect on static and dynamic behavior of vertical cavity surface emitting lasers

    Directory of Open Access Journals (Sweden)

    Sh.M. Eladl

    2017-12-01

    Full Text Available In this work, the effect of ionizing radiation on static and dynamic behavior of Vertical Cavity Surface Emitting Laser (VCSEL was investigated numerically. First, the model of dynamic behavior before irradiation has been analyzed based on Convolution Theorem. Second, all interesting ionizing radiation sensitive factors are compared with their corresponding post irradiation factors. The convolution theorem is applied to get features of dynamic behavior. All interesting parameters have been outlined. The effect of resonance frequency and damping parameters have been studied. The results show that static and dynamic response of these devices are dramatically deteriorated due to irradiation flux. The device gradually changes its mode of operation from lasing mode to LED mode by exhibiting weak oscillation of the output and fast damping with the increase of ionizing radiation. This type of model can be used for high data bit rate in multimode optical fiber network.

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

    OpenAIRE

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

    2016-01-01

    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 radiatio...

  20. 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.

  1. measurement of indoor background ionizing radiation in some

    African Journals Online (AJOL)

    Administrator

    These science laboratories also harbour a number of active radiation sources. The radiation levels were measured ... and the International Commission on Radiological Protection. (ICRP) show that residents of temperate climates ..... house construction. African Journal of Natural Sciences 5. Wentz, C. A. (1998): Safety, ...

  2. Ionizing radiation measurements and assay of corresponding dose

    African Journals Online (AJOL)

    PUBLICATIONS1

    tic effects of radiation to an acceptable level. (ICRP, 2012; 2013; UNSCEAR, 2001;. USNRC, 2005). According to international recommendations, occupational exposure to radiation should not exceed 20 mSv/yr, while the public should not be exposed to more than an average of 1 mSv/yr (IAEA, 2004; Strom,. 2003; USNRC ...

  3. Genomic damage in children accidentally exposed to ionizing radiation

    DEFF Research Database (Denmark)

    Fucic, A; Brunborg, G; Lasan, R

    2007-01-01

    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...

  4. 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...

  5. High and Low Doses of Ionizing Radiation Induce Different Secretome Profiles in a Human Skin Model

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Qibin; Matzke, Melissa M.; Schepmoes, Athena A.; Moore, Ronald J.; Webb-Robertson, Bobbie-Jo M.; Hu, Zeping; Monroe, Matthew E.; Qian, Weijun; Smith, Richard D.; Morgan, William F.

    2014-03-18

    It is postulated that secreted soluble factors are important contributors of bystander effect and adaptive responses observed in low dose ionizing radiation. Using multidimensional liquid chromatography-mass spectrometry based proteomics, we quantified the changes of skin tissue secretome – the proteins secreted from a full thickness, reconstituted 3-dimensional skin tissue model 48 hr after exposure to 3, 10 and 200 cGy of X-rays. Overall, 135 proteins showed statistical significant difference between the sham (0 cGy) and any of the irradiated groups (3, 10 or 200 cGy) on the basis of Dunnett adjusted t-test; among these, 97 proteins showed a trend of downregulation and 9 proteins showed a trend of upregulation with increasing radiation dose. In addition, there were 21 and 8 proteins observed to have irregular trends with the 10 cGy irradiated group either having the highest or the lowest level among all three radiated doses. Moreover, two proteins, carboxypeptidase E and ubiquitin carboxyl-terminal hydrolase isozyme L1 were sensitive to ionizing radiation, but relatively independent of radiation dose. Conversely, proteasome activator complex subunit 2 protein appeared to be sensitive to the dose of radiation, as rapid upregulation of this protein was observed when radiation doses were increased from 3, to 10 or 200 cGy. These results suggest that different mechanisms of action exist at the secretome level for low and high doses of ionizing radiation.

  6. Natural ionizing radiation exposure of the Spanish population.

    Science.gov (United States)

    García-Talavera, M; Matarranz, J L; Martínez, M; Salas, R; Ramos, L

    2007-01-01

    This study investigates the exposure of the Spanish population to natural radiation sources. The annual average effective dose is estimated to be 1.6 mSv, taking into account contributions from cosmic radiation (18%), terrestrial gamma radiation (30%), radon and thoron inhalation (34%) and ingestion (18%). Cosmic radiation doses were calculated from town altitude data. Terrestrial gamma ray exposure outdoors were derived from the MARNA (natural gamma radiation map of Spain); indoor exposure was obtained multiplying the corresponding outdoor value by an experimentally calculated conversion factor. Radon doses were estimated from national surveys carried out throughout the country. To assess doses by ingestion, data from a detailed study on consumption habits in Spain and average radioactivity values from UNSCEAR have been considered. The variability in the exposures among individuals in the population has been explicitly taken into account in the assessment.

  7. 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)

  8. Identification of novel senescence-associated genes in ionizing radiation-induced senescent carcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Seon; Kim, Bong Cho; Han, Na Kyung; Hong, Mi Na; Park, Su Min; Yoo, Hee Jung [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Chu, In Sun [Korea Research Institute of Bioscience and Biotechnology, Daejeon (Korea, Republic of); Lee, Sun Hee [Dong-A University, Busan (Korea, Republic of)

    2009-05-15

    Cellular senescence is considered as a defense mechanism to prevent tumorigenesis. Ionizing radiation (IR) induces stress-induced premature senescence as well as apoptosis in various cancer cells. Senescent cells undergo functional and morphological changes including large and flattened cell shape, senescence-associated {beta}-galactosidase (SA-{beta}Gal) activity, and altered gene expressions. Even with the recent findings of several gene expression profiles and supporting functional data, it is obscure that mechanism of IR-induced premature senescence in cancer cells. We performed microarray analysis to identify the common regulated genes in ionizing radiation-induced prematurely senescent human carcinoma cell lines.

  9. Anomalous effect of small doses of ionizing radiation on metals and alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chernov, I.P.; Mamontov, A.P.; Botaki, A.A.; Cherdantsev, P.A.; Chakhlov, B.V.; Sharov, S.R.; Timoshnikov, Yu.A.; Filipenko, L.A.

    1986-09-01

    The effect of small doses of /sup 60/Co gamma rays on copper, tungsten, and WCo alloys has been investigated. A decrease in the concentration of material defects under the influence of small doses of ionizing radiation was found. Also the structural rearrangement of the crystal was found to be still in progress after irradiation ceased. The mechanism of the anomalous effect of small doses of ionizing radiation on metals and alloys is discussed in terms of the electron energy scheme. (U.K.).

  10. Effects of ionizing radiation on cell cycle progression

    Energy Technology Data Exchange (ETDEWEB)

    Bernhard, E.J. [Dept. of Radiation Oncology, Univ. of Pennsylvania School of Medicine, Philadelphia, PA (United States); Maity, A. [Dept. of Radiation Oncology, Univ. of Pennsylvania School of Medicine, Philadelphia, PA (United States); Muschel, R.J. [Pathology and Lab. of Medicine, Univ. of Pennsylvania School of Medicine, Philadelphia, PA (United States); McKenna, W.G. [Dept. of Radiation Oncology, Univ. of Pennsylvania School of Medicine, Philadelphia, PA (United States)

    1995-06-01

    Control of radiation-induced G2 delay is likely to involve modulation of cyclin B1/p34{sup cdc2} activity. We have shown in HeLa cells that cyclin B1 expression is decreased in a dose-dependent manner following irradiation. This decrease is controlled at both the level of mRNA and protein accumulation. We have also shown that radiation-sensitive rat embryo fibroblast lines (REF) immortalized with v- or c-myc display a minimal G2 delay when compared to radiation resistant cells transformed with v-myc + H-ras. These REF lines respond to irradiation with a decrease in cyclin B mRNA, which parallels the extent of their respective G2 delays. The duration of the G2 delay in radiation-resistant REF can be shortened by treatment with low doses of the kinase inhibitor staurosporine. We have also been able to markedly reduce the radiation-induced G2 delay in HeLa cells using either staurosporine or caffeine. Attenuation of the G2 delay is accompanied by reversal of the radiation-induced inhibition of cyclin B mRNA accumulation. The results of these studies are consistent with the hypothesis that reduced expression of cyclin B in response to radiation is in part responsible for the G2 delay. The duration of the G2 delay may also be influenced by the activation state of the cyclin B/p34{sup cdc2} complex. (orig.)

  11. Effects of ionizing radiations on a pharmaceutical compound, chloramphenicol

    Science.gov (United States)

    Varshney, L.; Patel, K. M.

    1994-05-01

    Chloramphenicol, a broad spectrum antibiotic, has been irradiated using Cobalt-60 γ radiation and electron beam at graded radiation doses upto 100 kGy. Several degradation products and free radicals are formed on irradiation. Purity, degradation products, free radicals, discolouration, crystallinity, solubility and entropy of radiation processing have been investigated. Aqueous solutions undergo extensive radiolysis even at low doses. Physico-chemical, microbiological and toxicological tests do not show significant degradation at sterilization dose. High performance liquid chromatography (HPLC), differential scanning calorimetry (DSC), UV-spectrophotometry, diffuse reflectance spectroscopy (DRS) and electron spin resonance spectroscopy (ESR) techniques were employed for the investigations.

  12. 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)

  13. Calcium antagonists protect mice against lethal doses of ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Floersheim, G.L. (University Hospitals, Basel (Switzerland). Dept. of Research)

    1992-11-01

    Currently available radioprotectors are poorly tolerated in man and the general use of aminothiol radioprotectors is compromised by side-effects. In a search for less toxic radioprotective agents, diltiazem, a calcium antagonist with a benzothiazepine structure, was found to protect mice against a lethal (LD[sub 100]) [gamma] radiation dose allowing survival of up to 93%. Dihydropyridine calcium antagonists such as nifedipine, nimodipine, isradipine and nitrendipine also provided radioprotection. Calcium antagonists might attenuate radiation-induced injury by inhibiting cellular calcium overload, subsequent to cell membrane damage caused by radiation-generated free radicals. In view of their good tolerance, calcium antagonists may be applied safely in situations of radiation exposure, including radiotherapy and internal radionuclide contamination. These calcium antagonists may also be viewed in other contexts where free radicals are implicated in pathological processes. (Author).

  14. [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.

  15. Problems associated with microbiological validation of sterilization by ionizing radiation.

    Science.gov (United States)

    Harries, J E

    1998-01-01

    Potential solutions to some of the practical problems experienced when validating products processed by radiation sterilization are discussed in this article. The standards for validation and routine control of radiation sterilization are to be revised next year and there is now an opportunity for the industry to influence the effectiveness of those revisions. Medical device manufacturers are encouraged to make views known to help ensure a simpler standard that is widely implemented.

  16. The oncogenic action of ionizing radiation on rat skin

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-01-01

    An extensive experiment involving approximately 400 rats exposed to the neon ion beam at the Bevalac in Berkeley, CA and to electrons is nearing completion. Progress is described in three areas corresponding to the specific aims of the proposal: (1) carcinogenesis and DNA strand breaks in rat skin following exposure by the neon ions or electrons; (2) oncogene activation in radiation-induced rat skin cancers; (3) DNA strand breaks in the epidermis as a function of radiation penetration. 59 refs., 4 tabs.

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

    Science.gov (United States)

    2013-07-01

    antioxidants in the survival of prokaryotes under oxidative stress parallel the trends developing for the simple eukaryote Saccharomyces cerevisiae ...Escherichia coli, and Saccharomyces cerevisiae to Ionizing Radiation. ● New approaches to controlling the resistance properties of Bacillus spores...or a combination of these factors that are integral to achieving USAF objectives 10 Dr. Michael Daly is an accomplished scientist. He has been

  18. Ionizing radiation processing and its potential in advancing biorefining and nanocellulose composite materials manufacturing

    Science.gov (United States)

    Postek, Michael T.; Poster, Dianne L.; Vládar, András E.; Driscoll, Mark S.; LaVerne, Jay A.; Tsinas, Zois; Al-Sheikhly, Mohamad I.

    2018-02-01

    Nanocellulose is a high value material that has gained increasing attention because of its high strength, stiffness, unique photonic and piezoelectric properties, high stability and uniform structure. Through utilization of a biorefinery concept, nanocellulose can be produced in large volumes from wood at relatively low cost via ionizing radiation processing. Ionizing radiation causes significant break down of the polysaccharide and leads to the production of potentially useful gaseous products such as H2 and CO. The application of radiation processing to the production of nanocellulose from woody and non-wood sources, such as field grasses, bio-refining by-products, industrial pulp waste, and agricultural surplus materials remains an open field, ripe for innovation and application. Elucidating the mechanisms of the radiolytic decomposition of cellulose and the mass generation of nanocellulose by radiation processing is key to tapping into this source of nanocelluose for the growth of nanocellulostic-product development. More importantly, understanding the structural break-up of the cell walls as a function of radiation exposure is a key goal and only through careful, detailed characterization and dimensional metrology can this be achieved at the level of detail that is needed to further the growth of large scale radiation processing of plant materials. This work is resulting from strong collaborations between NIST and its academic partners who are pursuing the unique demonstration of applied ionizing radiation processing to plant materials as well as the development of manufacturing metrology for novel nanomaterials.

  19. Exposure of the surgical team to ionizing radiation during orthopedic surgical procedures☆☆☆

    Science.gov (United States)

    Palácio, Evandro Pereira; Ribeiro, André Araújo; Gavassi, Bruno Moreira; Di Stasi, Gabriel Guimarães; Galbiatti, José Antônio; Junior, Alcides Durigam; Mizobuchi, Roberto Ryuiti

    2014-01-01

    Objective the aim of this study was to assess the degree of exposure of the orthopedic surgical team to fluoroscopic ionizing radiation. Methods the ionizing radiation to which the orthopedic surgical team (R1, R2 and R3) was exposed was assayed using thermoluminescent dosimeters that were distributed in target anatomical regions (regions with and without protection using a lead apron). This was done during 45 hip osteosynthesis procedures to treat transtrochanteric fractures that were classified as 31-A2.1 (AO). Results the radioactive dose received by R3 was 6.33 mSv, R2 4.51 mSv and R3 1.99 mSv (p = 0.33). The thyroid region received 0.86 mSv of radiation, the thoracic region 1.24 mSv and the gonadal region 2.15 mSv (p = 0.25). There was no record of radiation at the dosimeters located below the biosafety protectors or on the team members’ backs. Conclusions the members of the surgical team who were located closest to the fluoroscope received greater radiation doses than those located further away. The anatomical regions located below the waistline were the ones that received most ionizing radiation. These results emphasize the importance of using biosafety devices, since these are effective in preventing radiation from reaching the vital organs of the medical team. PMID:26229805

  20. Exposure of the surgical team to ionizing radiation during orthopedic surgical procedures,

    Directory of Open Access Journals (Sweden)

    Evandro Pereira Palácio

    2014-06-01

    Full Text Available OBJECTIVE: the aim of this study was to assess the degree of exposure of the orthopedic surgical team to fluoroscopic ionizing radiation.METHODS: the ionizing radiation to which the orthopedic surgical team (R1, R2 and R3 was exposed was assayed using thermoluminescent dosimeters that were distributed in target anatomical regions (regions with and without protection using a lead apron. This was done during 45 hip osteosynthesis procedures to treat transtrochanteric fractures that were classified as 31-A2.1 (AO.RESULTS: the radioactive dose received by R3 was 6.33 mSv, R2 4.51 mSv and R3 1.99 mSv (p = 0.33. The thyroid region received 0.86 mSv of radiation, the thoracic region 1.24 mSv and the gonadal region 2.15 mSv (p = 0.25. There was no record of radiation at the dosimeters located below the biosafety protectors or on the team members' backs.CONCLUSIONS: the members of the surgical team who were located closest to the fluoroscope received greater radiation doses than those located further away. The anatomical regions located below the waistline were the ones that received most ionizing radiation. These results emphasize the importance of using biosafety devices, since these are effective in preventing radiation from reaching the vital organs of the medical team.

  1. Total Ionization Radiation Sensor Performance Improvement by Using Si-rich MONOS Device

    Directory of Open Access Journals (Sweden)

    Hsieh Wen-Ching

    2016-01-01

    Full Text Available The Si-rich metal -oxide-nitride-oxide-silicon (hereafter Si-MONOS can be candidates for non-volatile total ionization dose (TID radiation sensors. In the case of Si-MONOS gamma radiation sensors, the gamma radiation induces a significant decrease of threshold voltage VT. The change of VT for Si-MONOS after gamma irradiation has a strong correlation to the TID of gamma ray exposure as well. The Si-MONOS capacitor device in this study has demonstrated the better feasibility for non-volatile TID radiation sensing in the future.

  2. Effect Of Feedback On The Escape Of Ionizing Radiation From High-Z Galaxies

    Science.gov (United States)

    Trebitsch, Maxime; Blaizot, Jérémy; Rosdahl, Joakim; Devriendt, Julien; Slyz, Adrianne

    2017-06-01

    Quantifying how much of the ionizing radiation produced in high-redshift galaxies escapes in the IGM is one of the main challenges in understanding the sources of reionization. We investigate the radiative properties of simulated low mass galaxies (halos of a few 109 Msun at z=6), where radiation is modelled on-the-fly, and different sources of feedback (from stars and AGN) are included. Using radiation-hydrodynamic simulations performed with Ramses-RT we study how the energy and momentum input from supernovae and black hole activity modulates the properties of the interstellar medium and therefore how, and how many, photons can escape from the galaxy. I will present simulations showing (Trebitsch et al. 2017, https://arxiv.org/abs/1705.00941) that stellar feedback has a pivotal role in regulating the escape fraction in dwarf galaxies. Supernovae carve holes in the gas distribution, through which ionizing photons can escape.

  3. 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.

  4. Ovarian response to laser puncture in conditions of ionizing radiation

    Science.gov (United States)

    Vylegzhanina, T. A.; Ryzhkovskaya, E. L.

    1998-01-01

    Experimental results on long-term consequences of laser puncture applied to active points of the projection zones for the reproductive organs in guinea pigs after preliminary exposure to (gamma) -radiation are given. In female guinea pigs, it was shown that combination of external radiation (12.9 mCoul/kg) and incorporated 131I (6.5 mCi/kg) induced morphohistochemical and electron microscopic changes in the ovaries long (6 months) after, which indicated functional tension in the ovarian functioning. Laser biostimulation 3 months after the exposure to (gamma) - radiation induced severe injuries of the ovary, i.e. formation of thin-walled cysts, destruction of interstitial cells of the thecal sheath, by 6 months of the experiment. Functional incompetence of the organ was observed.

  5. A Role for Bioelectric Effects in the Induction of Bystander Signals by Ionizing Radiation?

    OpenAIRE

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

    2007-01-01

    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 expla...

  6. 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.

  7. Ionizing Radiation Measurements Using Low Cost Instruments for Teaching in College or High-School in Brazil

    Science.gov (United States)

    Silva, M. C.; Vilela, D. C.; Migoto, V. G.; Gomes, M. P.; Martin, I. M.; Germano, J. S. E.

    2017-01-01

    Ionizing radiation one of modern physics experimental teaching in colleges and high school can be easily implemented today due to low coasts of detectors and also electronic circuits and data acquisition interfaces. First it is interesting to show to young's students what is ionizing radiation and from where they appears near ground level? How it…

  8. Low-dose ionizing radiation alleviates Aβ42-induced defective phenotypes in Drosophila Alzheimer's disease models

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, SooJin; Jeong, Hae Min; Nam, Seon Young [Low-dose Radiation Research Team, Radiation Health Institute, Korea Hydro & Nuclear Power Co. Ltd., Daejeon (Korea, Republic of)

    2017-04-15

    Alzheimer's disease (AD) is the most common neurodegenerative disease that is characterized by amyloid plaques, progressive neuronal loss, and gradual deterioration of memory. Amyloid imaging using positron emission tomography (PET) radiotracers have been developed and approved for clinical use in the evaluation of suspected neurodegenerative disease, including AD. Particularly, previous studies involving low-dose ionizing radiation on Aβ 42-treated mouse hippocampal neurons have suggested a potential role for low-dose ionizing radiation in the treatment of AD. However, associated in vivo studies involving the therapy effects of low-dose ionizing radiation on AD are still insufficient. As a powerful cell biological system, Drosophila AD models have been generated and established a useful model organism for study on the etiology of human AD. In this study, we investigated the hormesis effects of low-dose ionizing radiation on Drosophila AD models. Our results suggest that low-dose ionizing radiation have the beneficial effects on not only the Aβ42-induced developmental defective phenotypes but also motor defects in Drosophila AD models. These results might be due to a regulation of apoptosis, and provide insight into the hormesis effects of low-dose ionizing radiation. Our results suggest that low-dose ionizing radiation have the beneficial effects on not only the Aβ42-induced developmental defective phenotypes but also motor defects in Drosophila AD models. These results might be due to a regulation of apoptosis, and provide insight into the hormesis effects of low-dose ionizing radiation.

  9. Cognitive, psychological and psychiatric effects of ionizing radiation exposure.

    Science.gov (United States)

    Marazziti, D; Baroni, S; Catena-Dell'Osso, M; Schiavi, E; Ceresoli, D; Conversano, C; Dell'Osso, L; Picano, E

    2012-01-01

    Radiation exposure leads to an increased risk for cancer and, possibly, additional ill-defined non-cancer risk, including atherosclerotic, cardiovascular, cerebro-vascular and neurodegenerative effects. Studies of brain irradiation in animals and humans provide evidence of apoptosis, neuro-inflammation, loss of oligo-dendrocytes precursors and myelin sheaths, and irreversible damage to the neural stem compartment with long-term impairment of adult neurogenesis. With the present paper we aim to present a comprehensive review on brain effects of radiation exposure, with a special focus on its impact on cognitive processes and psychological functions, as well as on their possible role in the pathophysiology of different psychiatric disorders.

  10. Oncogenic rearrangements driving ionizing radiation-associated human cancer.

    Science.gov (United States)

    Santoro, Massimo; Carlomagno, Francesca

    2013-11-01

    The Chernobyl nuclear disaster has caused a remarkable increase in radiation-induced papillary thyroid carcinoma in children and young adults. In this issue of the JCI, Ricarte-Filho and colleagues demonstrate that chromosomal rearrangements are the oncogenic "drivers" in most post-Chernobyl carcinomas and that they often lead to unscheduled activation of the MAPK signaling pathway. These findings represent a major step forward in our understanding of radiation-induced carcinogenesis and suggest various hypotheses about the mechanisms underlying the formation and selection of gene rearrangements during cancer cell evolution.

  11. 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

  12. 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.

  13. Effect of ionized plasma medium on the radiation from a RITMA ...

    Indian Academy of Sciences (India)

    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 ...

  14. Atmospheric Athena: 3D Atmospheric escape model with ionizing radiative transfer

    Science.gov (United States)

    Tripathi, Anjali; Krumholz, Mark R.

    2017-03-01

    Atmospheric Athena simulates hydrodynamic escape from close-in giant planets in 3D. It uses the Athena hydrodynamics code (ascl:1010.014) with a new ionizing radiative transfer implementation to self-consistently model photoionization driven winds from the planet. The code is fully compatible with static mesh refinement and MPI parallelization and can handle arbitrary planet potentials and stellar initial conditions.

  15. 38 CFR 3.311 - Claims based on exposure to ionizing radiation.

    Science.gov (United States)

    2010-07-01

    ...) Ovarian cancer; (xix) Parathyroid adenoma; (xx) Tumors of the brain and central nervous system; (xxi... veteran's age, gender, and pertinent family history; (iv) The veteran's history of exposure to known... ionizing radiation, of the specific pathology; (3) The veteran's gender and pertinent family history; (4...

  16. 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.

  17. 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.

  18. Frequency of Acentric Fragments Are Associated with Cancer Risk in Subjects Exposed to Ionizing Radiation.

    Czech Academy of Sciences Publication Activity Database

    Fucic, A.; Bonassi, S.; Gundy, S.; Šrám, Radim; Ceppi, M.; Lucas, J.N.

    2016-01-01

    Roč. 36, č. 5 (2016), s. 2451-2457 ISSN 0250-7005 Institutional support: RVO:68378041 Keywords : ionizing radiation * cancer risk * acentric fragments * chromosomal aberrations Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 1.937, year: 2016

  19. Clinical practitioners' knowledge of ionizing radiation doses in ...

    African Journals Online (AJOL)

    Background: Observation has shown a preponderance of irrelevant, unjustified and perhaps unnecessary radiological requests in the study area. The consequences of this on the patients' doses and population collective dose may be dire. Objective: To assess Clinicians/Referrers' knowledge of radiation doses of patients ...

  20. 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.

  1. Cytokine and chemokine responses after exposure to ionizing radiation: Implications for the astronauts

    Science.gov (United States)

    Laiakis, Evagelia C.; Baulch, Janet E.; Morgan, William F.

    For individuals traveling in space, exposure to space radiation is unavoidable. Since adequate shielding against radiation exposure is not practical, other strategies for protecting the astronauts must be developed. Radiation is also an important therapeutic and diagnostic tool, and evidence from the clinical and experimental settings now shows a firm connection between radiation exposure and changes in cytokine and chemokine levels. These small proteins can be pro- or anti-inflammatory in nature and the balance between those two effects can be altered easily because of exogenous stresses such as radiation. The challenge to identify a common perpetrator, however, lies in the fact that the cytokines that are produced vary based on radiation dose, type of radiation, and the cell types that are exposed. Based on current knowledge, special treatments have successfully been designed by implementing administration of proteins, antibodies, and drugs that counteract some of the harmful effects of radiation. Although these treatments show promising results in animal studies, it has been difficult to transfer those practices to the human situation. Further understanding of the mechanisms by which cytokines are triggered through radiation exposure and how those proteins interact with one another may permit the generation of novel strategies for radiation protection from the damaging effects of radiation. Here, we review evidence for the connection between cytokines and the radiation response and speculate on strategies by which modulating cytokine responses may protect astronauts against the detrimental effects of ionizing radiations.

  2. Serotonin and ionizing radiation synergistically affect proliferation and adhesion molecule expression of malignant melanoma cells.

    Science.gov (United States)

    Müller, Kerstin; Gilbertz, Klaus-Peter; Meineke, Viktor

    2012-11-01

    Mast cells are key effectors of the immune system and are involved in a variety of physiological and pathophysiological processes. Dermal mast cells have been demonstrated to degranulate as a consequence of ionizing radiation exposure. Mast cells accumulate at the periphery of skin tumours including malignant melanoma. Melanoma cells thus represent a potential target for the action of mediators released from irradiated mast cells. In this study, we evaluated the effects of serotonin and ionizing radiation on the proliferation and the adhesion molecule expression of malignant melanoma cells. Human mast cells (HMC-1) were examined for serotonin release after irradiation using an enzyme-linked immunosorbent assay (ELISA). Protein expression of serotonin receptors and adhesion molecules on human melanoma cells (IPC-298) was investigated by flow cytometry. Cell attachment to fibronectin was determined by an adhesion assay. Proliferation and cell cycle kinetics were analysed by proliferation assay and 5-bromodeoxyuridine (BrdU)/DNA dual parameter flow cytometry, respectively. Ionizing radiation exposure resulted in serotonin release by HMC-1 cells. Expression of serotonin receptors was detected on IPC-298 cells. Serotonin enhanced the radiation-induced reduction in melanoma cell proliferation. Serotonin and ionizing radiation synergistically increased the expression of adhesion molecules on melanoma cells and improved cell adhesion to fibronectin. The up-regulation of cellular adhesion molecule expression was attenuated by inhibitors to phosphatidylinositol 3-kinase, mitogen-activated protein (MAP) ERK kinase and protein kinase C. Our data suggest that serotonin released from irradiated dermal mast cells modulates the radiation response of human melanoma cells. We postulate that radiation-induced mast cell degranulation and mediator release have a great impact on malignant melanoma cell development. Copyright © 2012 Japanese Society for Investigative Dermatology

  3. 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

  4. Stable chromosome aberrations and ionizing radiation in airline pilots.

    Science.gov (United States)

    Nicholas, J S; Butler, G C; Davis, S; Bryant, E; Hoel, D G; Mohr, L C

    2003-09-01

    The purpose of this study was to determine the frequency of translocations and insertions in the blood of long-term pilots in relation to estimated cumulative radiation dose received while flying, and to compare that to the frequency in a group of similarly aged men without a history of frequent airline travel. Healthy, non-smoking male pilots aged 40-60 yr were recruited from a single airline. Non-pilot controls were recruited from healthy, non-smoking professional males in the same age range and without a history of frequent flying. Eligibility was determined based on screening surveys. Career pilot radiation doses were calculated individually using airline flight profiles, personal flight history, and the CARI computer program. Translocation frequency was determined using fluorescence in situ hybridization. Blood samples for chromosome analysis were provided by 19 individuals. The mean number of metaphases counted per subject was 2802 in the pilots and 3000 in the controls. The mean number of translocations per cell (genome equivalent) was significantly higher among the pilots (mean +/- SE; 0.0031 +/- 0.0008) than among the controls (0.0010 +/- 0.0003) (p = 0.03, Mann-Whitney U test). However, within the 26 to 72 millisievert range encountered in this study, observed values among the pilots did not follow the dose-response pattern expected based on available models for chronic low dose radiation exposure. There was a statistically significant higher number of translocations per cell among pilots than among controls, although the expected dose-response relationship for radiation was not observed among the pilots.

  5. Highly sensitive detection of ionizing radiations by a photoluminescent uranyl organic framework

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Jian; Wang, Yaxing; Liu, Wei; Yin, Xuemiao; Chen, Lanhua; Diwu, Juan; Chai, Zhifang; Wang, Shuao [School for Radiological and interdisciplinary Sciences (RAD-X) and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou (China); Zou, Youming [High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui (China); Albrecht-Schmitt, Thomas E. [Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL (United States); Liu, Guokui [Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL (United States)

    2017-06-19

    Precise detection of low-dose X- and γ-radiations remains a challenge and is particularly important for studying biological effects under low-dose ionizing radiation, safety control in medical radiation treatment, survey of environmental radiation background, and monitoring cosmic radiations. We report here a photoluminescent uranium organic framework, whose photoluminescence intensity can be accurately correlated with the exposure dose of X- or γ-radiations. This allows for precise and instant detection of ionizing radiations down to the level of 10{sup -4} Gy, representing a significant improvement on the detection limit of approximately two orders of magnitude, compared to other chemical dosimeters reported up to now. The electron paramagnetic resonance analysis suggests that with the exposure to radiations, the carbonyl double bonds break affording oxo-radicals that can be stabilized within the conjugated uranium oxalate-carboxylate sheet. This gives rise to a substantially enhanced equatorial bonding of the uranyl(VI) ions as elucidated by the single-crystal structure of the γ-ray irradiated material, and subsequently leads to a very effective photoluminescence quenching through phonon-assisted relaxation. The quenched sample can be easily recovered by heating, enabling recycled detection for multiple runs. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Overview of atmospheric ionizing radiation (AIR) Research: SST-present

    Science.gov (United States)

    Wilson, J. W.; Goldhagen, P.; Rafnsson, V.; Clem, J. M.; De Angelis, G.; Friedberg, W.

    The Supersonic Transport (SST) program proposed in 1961, first raised concern for the exposure of pregnant occupants by solar energetic particles (SEP), and neutrons were suspected to have a main role in particle propagation deep into the atmosphere. An eight-year flight program confirmed the role of SEP as a significant hazard and of the neutrons as contributing over half of the galactic cosmic ray exposures, with the largest contribution from neutrons above 10 MeV. The FAA Advisory Committee on the Radiobiological Aspects of the SST provided operational requirements. The more recent lowering of ICRP-recommended exposure limits 1990 with the classification of aircrew as "radiation workers" renewed interest in GCR background exposures at commercial flight altitudes and stimulated epidemiological studies in Europe, Japan, Canada and the USA. The proposed development of a High Speed Civil Transport (HSCT) required validation of the role of high-energy neutrons, and this resulted in ER-2 flights at solar minimum June 1997 and studies on effects of aircraft materials on interior exposures. Recent evaluation of health outcomes of DOE nuclear workers resulted in legislation for health compensation in year 2000 and recent European aircrew epidemiological studies of health outcomes bring renewed interest in aircraft radiation exposures. As improved radiation models become available, it is imperative that a corresponding epidemiological program of US aircrew be implemented.

  7. Ionizing radiation effects in Brazilian grape tree wine

    Energy Technology Data Exchange (ETDEWEB)

    Harder, Marcia N.C.; Gutierrez, Érika M.R., E-mail: marcia.harder@fatec.sp.gov.br, E-mail: emrgutierrez@hotmail.com [Faculdade de Tecnologia de Piracicaba (FATEC), Piracicaba, SP (Brazil). Curso de Tecnologia em Alimentos. Dep. Roque Trevisan; Pires, Juliana A., E-mail: juliana.angelo@gmail.com [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNE-SP), São Paulo, SP (Brazil); Arthur, Valter; Silva, Lúcia C.A.S., E-mail: arthur@cena.usp.br, E-mail: lcasilva@cena.usp.br [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil)

    2017-07-01

    The aim of this work was to irradiate brazilian grape tree wines with gamma radiation (Co{sup 60}) to investigate the effect of radiation on its components and to create a new product for the superior quality fermented beverages market. For this wine was produced in an artisan way, but with all the care of hygiene and sanitation. The brazilian grape tree was fermented for five days and the wine was then filtered and stored in inert material containers then irradiated at 2.5 and 5 kGy doses. The samples were evaluated in relation to the radiation doses used. Physical and chemical analyzes of pH; total and volatile acidity; alcohol content; anthocyanins; tannins and colorimetry were performed. As a result, in most product analysis, had little effect on irradiation, except for anthocyanins and tannins. For this can be concluded that it is possible to develop a new fermented drink based on brazilian grape tree, according to the standards required by the legislation and that the irradiation at the dose of 5kGy was the sample that shown to have the most effect on the color because it was the one that degraded most molecules of anthocyanins and tannins. (author)

  8. 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.

  9. Diet-induced obesity modulates epigenetic responses to ionizing radiation in mice.

    Directory of Open Access Journals (Sweden)

    Guillaume Vares

    Full Text Available Both exposure to ionizing radiation and obesity have been associated with various pathologies including cancer. There is a crucial need in better understanding the interactions between ionizing radiation effects (especially at low doses and other risk factors, such as obesity. In order to evaluate radiation responses in obese animals, C3H and C57BL/6J mice fed a control normal fat or a high fat (HF diet were exposed to fractionated doses of X-rays (0.75 Gy ×4. Bone marrow micronucleus assays did not suggest a modulation of radiation-induced genotoxicity by HF diet. Using MSP, we observed that the promoters of p16 and Dapk genes were methylated in the livers of C57BL/6J mice fed a HF diet (irradiated and non-irradiated; Mgmt promoter was methylated in irradiated and/or HF diet-fed mice. In addition, methylation PCR arrays identified Ep300 and Socs1 (whose promoters exhibited higher methylation levels in non-irradiated HF diet-fed mice as potential targets for further studies. We then compared microRNA regulations after radiation exposure in the livers of C57BL/6J mice fed a normal or an HF diet, using microRNA arrays. Interestingly, radiation-triggered microRNA regulations observed in normal mice were not observed in obese mice. miR-466e was upregulated in non-irradiated obese mice. In vitro free fatty acid (palmitic acid, oleic acid administration sensitized AML12 mouse liver cells to ionizing radiation, but the inhibition of miR-466e counteracted this radio-sensitization, suggesting that the modulation of radiation responses by diet-induced obesity might involve miR-466e expression. All together, our results suggested the existence of dietary effects on radiation responses (especially epigenetic regulations in mice, possibly in relationship with obesity-induced chronic oxidative stress.

  10. Diet-induced obesity modulates epigenetic responses to ionizing radiation in mice.

    Science.gov (United States)

    Vares, Guillaume; Wang, Bing; Ishii-Ohba, Hiroko; Nenoi, Mitsuru; Nakajima, Tetsuo

    2014-01-01

    Both exposure to ionizing radiation and obesity have been associated with various pathologies including cancer. There is a crucial need in better understanding the interactions between ionizing radiation effects (especially at low doses) and other risk factors, such as obesity. In order to evaluate radiation responses in obese animals, C3H and C57BL/6J mice fed a control normal fat or a high fat (HF) diet were exposed to fractionated doses of X-rays (0.75 Gy ×4). Bone marrow micronucleus assays did not suggest a modulation of radiation-induced genotoxicity by HF diet. Using MSP, we observed that the promoters of p16 and Dapk genes were methylated in the livers of C57BL/6J mice fed a HF diet (irradiated and non-irradiated); Mgmt promoter was methylated in irradiated and/or HF diet-fed mice. In addition, methylation PCR arrays identified Ep300 and Socs1 (whose promoters exhibited higher methylation levels in non-irradiated HF diet-fed mice) as potential targets for further studies. We then compared microRNA regulations after radiation exposure in the livers of C57BL/6J mice fed a normal or an HF diet, using microRNA arrays. Interestingly, radiation-triggered microRNA regulations observed in normal mice were not observed in obese mice. miR-466e was upregulated in non-irradiated obese mice. In vitro free fatty acid (palmitic acid, oleic acid) administration sensitized AML12 mouse liver cells to ionizing radiation, but the inhibition of miR-466e counteracted this radio-sensitization, suggesting that the modulation of radiation responses by diet-induced obesity might involve miR-466e expression. All together, our results suggested the existence of dietary effects on radiation responses (especially epigenetic regulations) in mice, possibly in relationship with obesity-induced chronic oxidative stress.

  11. Mortality from diseases other than cancer following low doses of ionizing radiation

    DEFF Research Database (Denmark)

    Vrijheid, M; Cardis, E; Ashmore, P

    2007-01-01

    BACKGROUND: Ionizing radiation at very high (radio-therapeutic) dose levels can cause diseases other than cancer, particularly heart diseases. There is increasing evidence that doses of the order of a few sievert (Sv) may also increase the risk of non-cancer diseases. It is not known, however......, whether such effects also occur following the lower doses and dose rates of public health concern. METHODS: We used data from an international (15-country) nuclear workers cohort study to evaluate whether mortality from diseases other than cancer is related to low doses of external ionizing radiation....... Analyses included 275 312 workers with adequate information on socioeconomic status, over 4 million person-years of follow-up and an average cumulative radiation dose of 20.7 mSv; 11 255 workers had died of non-cancer diseases. RESULTS: The excess relative risk (ERR) per Sv was 0.24 [95% CI (confidence...

  12. Interpreting the star formation efficiency of nearby molecular clouds with ionizing radiation

    Science.gov (United States)

    Geen, Sam; Soler, Juan D.; Hennebelle, Patrick

    2017-11-01

    We investigate the origin of observed local star formation relations using radiative magnetohydrodynamic simulations with self-consistent star formation and ionizing radiation. We compare these clouds to the density distributions of local star-forming clouds and find that the most diffuse simulated clouds match the observed clouds relatively well. We then compute both observationally motivated and theoretically motivated star formation efficiencies (SFEs) for these simulated clouds. By including ionizing radiation, we can reproduce the observed SFEs in the clouds most similar to nearby Milky Way clouds. For denser clouds, the SFE can approach unity. These observed SFEs are typically 3 to 10 times larger than the `total' SFEs, I.e. the fraction of the initial cloud mass converted into stars. Converting observed into total SFEs is non-trivial. We suggest some techniques for doing so, though estimate up to a factor of 10 error in the conversion.

  13. The Influence of Ionizing Radiation on Itraconazole in the Solid State

    OpenAIRE

    Dettlaff, Katarzyna; Talik, Przemys?aw; Sp?lnik, Grzegorz; Danikiewicz, Witold; Ogrodowczyk, Magdalena

    2014-01-01

    The aim of this study was to investigate the ionizing radiation effects, in the form of an electron beam, on itraconazole (ITR) in the solid phase. It was found that the ITR, under the influence of a standard 25?kGy dose of radiation used for the sterilization of drug substances, decomposed at 0.4%. Moreover, a gentle change of colour and a decrease in melting point does not exceed pharmacopoeial standards causing that ITR can be sterilized by radiation method. The use of high 400?kGy radiati...

  14. Determination of the ionization potentials of security-relevant substances with single photon ionization mass spectrometry using synchrotron radiation.

    Science.gov (United States)

    Schramm, E; Mühlberger, F; Mitschke, S; Reichardt, G; Schulte-Ladbeck, R; Pütz, M; Zimmermann, R

    2008-02-01

    Several ionization potentials (IPs) of security relevant substances were determined with single photon ionization time of flight mass spectrometry (SPI-TOFMS) using monochromatized synchrotron radiation from the "Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung" (BESSY). In detail, the IPs of nine explosives and related compounds, seven narcotics and narcotics precursors, and one chemical warfare agent (CWA) precursor were determined, whereas six IPs already known from the literature were verified correctly. From seven other substances, including one CWA precursor, the IP could not be determined as the molecule ion peak could not be detected. For these substances the appearance energy (AE) of a main fragment was determined. The analyzed security-relevant substances showed IPs significantly below the IPs of common matrix compounds such as nitrogen and oxygen. Therefore, it is possible to find photon energies in between, whereby the molecules of interest can be detected with SPI in very low concentrations due to the shielding of the matrix. All determined IPs except the one of the explosive EGDN were below 10.5 eV. Hence, laser-generated 118 nm photons can be applied for detecting almost all security-relevant substances by, e.g., SPI-TOFMS.

  15. Ionizing radiation, nuclear energy and radiation protection for school; Radiacao ionizante, energia nuclear e protecao radiologica para a escola

    Energy Technology Data Exchange (ETDEWEB)

    Lucena, E.A.; Reis, R.G.; Pinho, A.S.; Alves, A.S.; Rio, M.A.P.; Reis, A.A., E-mail: arlene@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Silva, J.W.S. [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil); Paula, G.A. de; Goncalves Junior, M.A. [Escola Sesc de Ensino Medio, Rio de Janeiro, RJ (Brazil)

    2017-04-01

    Since the discovery of X-rays in 1895, ionizing radiation has been applied in many sectors of society, such as medicine, industry, safety, construction, engineering and research. However, population is unaware of both the applications of ionizing radiation and their risks and benefits. It can be seen that most people associate the terms 'radiation' and 'nuclear energy' with the atomic bomb or cancer, most likely because of warlike applications and the stealthy way radioactivity had been treated in the past. Thus, it is necessary to clarify the population about the main aspects related to the applications, risks and associated benefits. These knowledge can be disseminated in schools. Brazilian legislation for basic education provides for topics such as nuclear energy and radioactivity to high school students. However, some factors hamper such an educational practice, namely, few hours of class, textbooks do not address the subject, previous concepts obtained in the media, difficulty in dealing with the subject in the classroom, phobia, etc. One solution would be the approximation between schools and institutions that employ technologies involving radioactivity, which would allow students to know the practices, associated radiological protection, as well as the risks and benefits to society. Currently, with the increasing application of ionizing radiation, especially in medicine, it is necessary to demystify the use of radioactivity. (author)

  16. Ionizing Radiation Affects Gene Expression in Mouse Skin and Bone

    Science.gov (United States)

    Terada, Masahiro; Tahimic, Candice; Sowa, Marianne B.; Schreurs, Ann-Sofie; Shirazi-Fard, Yasaman; Alwood, Joshua; Globus, Ruth K.

    2017-01-01

    Future long-duration space exploration beyond low earth orbit will increase human exposure to space radiation and microgravity conditions as well as associated risks to skeletal health. In animal studies, radiation exposure (greater than 1 Gy) is associated with pathological changes in bone structure, enhanced bone resorption, reduced bone formation and decreased bone mineral density, which can lead to skeletal fragility. Definitive measurements and detection of bone loss typically require large and specialized equipment which can make their application to long duration space missions logistically challenging. Towards the goal of developing non-invasive and less complicated monitoring methods to predict astronauts' health during spaceflight, we examined whether radiation induced gene expression changes in skin may be predictive of the responses of skeletal tissue to radiation exposure. We examined oxidative stress and growth arrest pathways in mouse skin and long bones by measuring gene expression levels via quantitative polymerase chain reaction (qPCR) after exposure to total body irradiation (IR). To investigate the effects of irradiation on gene expression, we used skin and femora (cortical shaft) from the following treatment groups: control (normally loaded, sham-irradiated), and IR (0.5 Gy 56Fe 600 MeV/n and 0.5 Gy 1H 150 MeV/n), euthanized at one and 11 days post-irradiation (IR). To determine the extent of bone loss, tibiae were harvested and cancellous microarchitecture in the proximal tibia quantified ex vivo using microcomputed tomography (microCT). Statistical analysis was performed using Student's t-test. At one day post-IR, expression of FGF18 in skin was significantly greater (3.8X) than sham-irradiated controls, but did not differ at 11 days post IR. Expression levels of other genes associated with antioxidant response (Nfe2l2, FoxO3 and Sod1) and the cell cycle (Trp53, Cdkn1a, Gadd45g) did not significantly differ between the control and IR groups

  17. Disordered redox metabolism of brain cells in rats exposed to low doses of ionizing radiation or UHF electromagnetic radiation.

    Science.gov (United States)

    Burlaka, A P; Druzhyna, M O; Vovk, A V; Lukin, S М

    2016-12-01

    To investigate the changes of redox-state of mammalian brain cells as the critical factor of initiation and formation of radiation damage of biological structures in setting of continuous exposure to low doses of ionizing radiation or fractionated ultra high frequency electromagnetic radiation (UHF EMR) at non-thermal levels. The influence of low-intensity ionizing radiation was studied on outbred female rats kept for 1.5 years in the Chernobyl accident zone. The effects of total EMR in the UHF band of non-thermal spectrum were investigated on Wistar rats. The rate of formation of superoxide radicals and the rate of NO synthesis in mitochondria were determined by the EPR. After exposure to ionizing or UHF radiation, the levels of ubisemiquinone in brain tissue of rats decreased by 3 and 1.8 times, respectively. The content of NO-FeS-protein complexes in both groups increased significantly (р < 0.05). In the conditions of ionizing or EMR the rates of superoxide radical generation in electron-transport chain of brain cell mitochondria increased by 1.5- and 2-fold, respectively (р < 0.05). In brain tissue of rats kept in the Chernobyl zone, significant increase of NO content was registered; similar effect was observed in rats treated with UHFR (р < 0.05). The detected changes in the electron transport chain of mitochondria of brain cells upon low-intensity irradiation or UHF EMR cause the metabolic reprogramming of cell mitochondria that increases the rate of superoxide radical generation and nitric oxide, which may initiate the development of neurodegenerative diseases and cancer. This article is part of a Special Issue entitled "The Chornobyl Nuclear Accident: Thirty Years After".

  18. 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.)

  19. Apparatus and method for the simultaneous detection of neutrons and ionizing electromagnetic radiation

    Science.gov (United States)

    Bell, Zane W.

    2000-01-01

    A sensor for simultaneously detecting neutrons and ionizing electromagnetic radiation comprising: a sensor for the detection of gamma radiation, the sensor defining a sensing head; the sensor further defining an output end in communication with the sensing head; and an exterior neutron-sensitive material configured to form around the sensing head; wherein the neutron-sensitive material, subsequent to the capture of the neutron, fissions into an alpha-particle and a .sup.7 Li ion that is in a first excited state in a majority of the fissions, the first excited state decaying via the emission of a single gamma ray at 478 keV which can in turn be detected by the sensing head; and wherein the sensing head can also detect the ionizing electromagnetic radiation from an incident radiation field without significant interference from the neutron-sensitive material. A method for simultaneously detecting neutrons and ionizing electromagnetic radiation comprising the steps of: providing a gamma ray sensitive detector comprising a sensing head and an output end; conforming an exterior neutron-sensitive material configured to form around the sensing head of the detector; capturing neutrons by the sensing head causing the neutron-sensitive material to fission into an alpha-particle and a .sup.7 Li ion that is in a first excited state in a majority of the fissions, the state decaying via the emission of a single gamma ray at 478 keV; sensing gamma rays entering the detector through the neutron-sensitive material; and producing an output through a readout device coupled to the output end; wherein the detector provides an output which is proportional to the energy of the absorbed ionizing electromagnetic radiation.

  20. Ionic composition of a humid air plasma under ionizing radiation

    Science.gov (United States)

    Filippov, A. V.; Derbenev, I. N.; Dyatko, N. A.; Kurkin, S. A.; Lopantseva, G. B.; Pal', A. F.; Starostin, A. N.

    2017-08-01

    A kinetic model is proposed for ion-molecular processes involving charged particles of a humid air plasma produced by a fast electron beam. The model includes more than 600 processes involving electrons and 41 positive and 14 negative ions, including hydrated ions H3O+ (H2O) n and O 2 - (H2O) n with n = 1, 2, …, 12. The energy costs of production of electron-ion pairs and electronic and vibrational (for water molecules, also rotational) excitation of molecules are calculated in nitrogen, oxygen, water vapor, air, and humid air. A method is proposed for calculating the energy costs in mixtures by the calculation data in pure gases. The evolution of the plasma composition is studied by the numerical solution of a system of 56 time-dependent balance equations for the number of charged particles of plasma by the fourth-order Runge-Kutta method. The steady-state composition of plasma is determined by solving nonlinear steady-state balance equations for the ionization rates of humid air from 10 to 1016 cm-3/s and the fraction of water molecules from 10-3% to 1.5%. It is established that, for water vapor content (the ratio of the number density of water molecules to the total number density of air molecules) of 0.015-1.5% in air at atmospheric pressure and room temperature, the main ion species are two types of positive ions H3O+ (H2O) n with the number of water molecules n = 5, 6 and three species of negative ions O 2 - (H2O) n with n = 5, 8, 9.

  1. Computer image analysis of etched tracks from ionizing radiation

    Science.gov (United States)

    Blanford, George E.

    1994-01-01

    I proposed to continue a cooperative research project with Dr. David S. McKay concerning image analysis of tracks. Last summer we showed that we could measure track densities using the Oxford Instruments eXL computer and software that is attached to an ISI scanning electron microscope (SEM) located in building 31 at JSC. To reduce the dependence on JSC equipment, we proposed to transfer the SEM images to UHCL for analysis. Last summer we developed techniques to use digitized scanning electron micrographs and computer image analysis programs to measure track densities in lunar soil grains. Tracks were formed by highly ionizing solar energetic particles and cosmic rays during near surface exposure on the Moon. The track densities are related to the exposure conditions (depth and time). Distributions of the number of grains as a function of their track densities can reveal the modality of soil maturation. As part of a consortium effort to better understand the maturation of lunar soil and its relation to its infrared reflectance properties, we worked on lunar samples 67701,205 and 61221,134. These samples were etched for a shorter time (6 hours) than last summer's sample and this difference has presented problems for establishing the correct analysis conditions. We used computer counting and measurement of area to obtain preliminary track densities and a track density distribution that we could interpret for sample 67701,205. This sample is a submature soil consisting of approximately 85 percent mature soil mixed with approximately 15 percent immature, but not pristine, soil.

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

    Science.gov (United States)

    Jaskot, A. E.; Oey, M. S.

    2013-04-01

    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' Sloan Digital Sky Survey (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 λ3819 emission in the extreme Peas support young ages of 3-5 Myr, and He II λ4686 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 Peas' line ratios and ages. Although stacked spectra reveal no Wolf-Rayet (WR) features, we tentatively detect WR features in the SDSS spectra of three extreme Peas. Based on the Peas' ages and line ratios, we find that WR stars, chemically homogeneous O stars, or shocks could produce the observed He II emission. If hot stars are responsible, then the Peas' optical depths are ambiguous. However, accounting for emission from shocks lowers the inferred optical depth and suggests that the Peas may be optically thin. The Peas' ages likely optimize the escape of LyC radiation; they are old enough for supernovae and stellar winds to reshape the interstellar medium, but young enough to possess large numbers of UV-luminous O or WR stars.

  3. 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

  4. Vitamin E protects salivary glands dysfunction induced by ionizing radiation in rats.

    Science.gov (United States)

    Abedi, Seyed Mohammad; Yarmand, Fateme; Motallebnejad, Mina; Seyedmajidi, Maryam; Moslemi, Dariush; Ashrafpour, Manouchehr; Bijani, Ali; Moghadamnia, Aliakbar; Mardanshahi, Alireza; Hosseinimehr, Seyed Jalal

    2015-09-01

    The purpose of this study is to investigate the radioprotective effect of vitamin E as a natural product. Vitamin E protects the salivary glands dysfunction that is induced by ionizing radiation. It was analysed with radioisotope scintigraphy and then salivary gland to background counts ratio was calculated. Histopathological evaluation was performed. The rats were treated with vitamin E at dose of 400IU/kg 48, 24, and 1h before 15Gy gamma rays irradiation. The rats were evaluated for the salivary gland function through nuclear medicine protocol. Radiation causes significant salivary glands dysfunction at the 3rd and the 70th days with a reduction in radioactivity uptake in the salivary glands. Ratios of salivary gland to background radioactivities were 1.99±0.11, 1.58±0.08 and 1.92±0.04 for control, radiation, and vitamin E plus radiation groups, respectively. Vitamin E significantly improved salivary gland dysfunction induced by ionizing radiation in the rats. In conclusion, our results indicate protective effects of vitamin E against salivary gland dysfunction induced by gamma radiation. Thus, vitamin E is a promising radioprotective agent for patients who receive radiation in head and neck cancer therapy. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2011-01-01

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

  6. 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.)

  7. 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.

  8. 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)

  9. [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.

  10. Astrophysical cosmology

    Science.gov (United States)

    Bardeen, J. M.

    The last several years have seen a tremendous ferment of activity in astrophysical cosmology. Much of the theoretical impetus has come from particle physics theories of the early universe and candidates for dark matter, but what promise to be even more significant are improved direct observations of high z galaxies and intergalactic matter, deeper and more comprehensive redshift surveys, and the increasing power of computer simulations of the dynamical evolution of large scale structure. Upper limits on the anisotropy of the microwave background radiation are gradually getting tighter and constraining more severely theoretical scenarios for the evolution of the universe.

  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. The use of DRS and GC to study the effects of ionizing radiation on paper artifacts

    Directory of Open Access Journals (Sweden)

    Głuszewski Wojciech

    2015-09-01

    Full Text Available Radiation preservation of objects of historical significance is an interesting proposition for museums, archives, libraries and private collectors. In this paper, we have limited ourselves to studying the effects of ionizing radiation on the paper. The radiation resistance of various grades of paper was examined in INCT. Irradiations were done by electron beam (10 MeV, 10 kW and by gamma radiation (7 kG/h, for the purpose of comparison. Yields of hydrogen and absorption of oxygen were determined by gas chromatography (GC. For this purpose, the first time in an original way was used diffuse reflection spectroscopy (DRS. Described as the dose, dose rate, and lignin were found to affect degradation processes of cellulose. Examined the protective effect of lignin in the process of radiation degradation of paper. Proposed research methodology can be successfully applied to study other materials relevant to the conservation of works of art.

  13. 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.

  14. 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

  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. Temperature-responsive copolymeric hydrogel systems synthetized by ionizing radiation

    Science.gov (United States)

    López-Barriguete, Jesús Eduardo; Bucio, Emilio

    2017-06-01

    Eight different systems of hydrogel copolymers with diverse temperature responsiveness were prepared to elaborate membranes for their biomedical application. The hydrogels were synthesized using poly(N-isopropylacrylamide) (PNIPAAm) and poly(N-vinylcaprolactam) (PNVCL), which have a low critical solution temperature (LCST) close to that of the human body temperature. The networks were synthesized using gamma radiation at a dose rate of 11.2 kGy h-1, and dose of 50 kGy. The LCST of each system was measured by differential scanning calorimetry (DSC). The effect of using hydrophilic monomers of acrylic acid (AAc), methacrylic acid (MAAc), dimethyl acrylamide (DMAAm), and hydroxyethyl methacrylate (HEMA) for the copolymerization on the critical point was evaluated. Five viable systems were obtained, with the best hydrogel being that of poly(NIPAAm-co-DMAAm), which an LCST at 39.8 °C. All the samples were characterized by FTIR-ATR, DSC, TGA, X-Ray Diffraction, and SEM. The proportion of monomers during the formation of the copolymers was decisive in the displacement of the LCST.

  17. Characterization of a novel epigenetic effect of ionizing radiation: the death-inducing effect

    Science.gov (United States)

    Nagar, Shruti; Smith, Leslie E.; Morgan, William F.

    2003-01-01

    The detrimental effects associated with exposure to ionizing radiation have long been thought to result from the direct targeting of the nucleus leading to DNA damage; however, the emergence of concepts such as radiation-induced genomic instability and bystander effects have challenged this dogma. After cellular exposure to ionizing radiation, we have isolated a number of clones of Chinese hamster-human hybrid GM10115 cells that demonstrate genomic instability as measured by chromosomal destabilization. These clones show dynamic and persistent generation of chromosomal rearrangements multiple generations after the original insult. We hypothesize that these unstable clones maintain this delayed instability phenotype by secreting factors into the culture medium. To test this hypothesis we transferred filtered medium from unstable cells to unirradiated GM10115 cells. No GM10115 cells were able to survive this medium. This phenomenon by which GM10115 cells die when cultured in medium from chromosomally unstable GM10115 clones is the death-inducing effect. Medium transfer experiments indicate that a factor or factors is/are secreted by unstable cells within 8 h of growth in fresh medium and result in cell killing within 24 h. These factors are stable at ambient temperature but do not survive heating or freezing, and are biologically active when diluted with fresh medium. We present the initial description and characterization of the death-inducing effect. This novel epigenetic effect of radiation has implications for radiation risk assessment and for health risks associated with radiation exposure.

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

    Directory of Open Access Journals (Sweden)

    S. V. Trofymenko

    2016-11-01

    Full Text Available 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.

  19. Membrane Signaling Induced by High Doses of Ionizing Radiation in the Endothelial Compartment. Relevance in Radiation Toxicity

    Directory of Open Access Journals (Sweden)

    Isabelle Corre

    2013-11-01

    Full Text Available Tumor areas can now be very precisely delimited thanks to technical progress in imaging and ballistics. This has also led to the development of novel radiotherapy protocols, delivering higher doses of ionizing radiation directly to cancer cells. Despite this, radiation toxicity in healthy tissue remains a major issue, particularly with dose-escalation in these new protocols. Acute and late tissue damage following irradiation have both been linked to the endothelium irrigating normal tissues. The molecular mechanisms involved in the endothelial response to high doses of radiation are associated with signaling from the plasma membrane, mainly via the acid sphingomyelinase/ceramide pathway. This review describes this signaling pathway and discusses the relevance of targeting endothelial signaling to protect healthy tissues from the deleterious effects of high doses of radiation.

  20. Atorvastatin mitigates testicular injuries induced by ionizing radiation in mice.

    Science.gov (United States)

    Naeimi, Ramezan Ali; Talebpour Amiri, Fereshteh; Khalatbary, Ali Reza; Ghasemi, Arash; Zargari, Mehryar; Ghesemi, Maryam; Hosseinimehr, Seyed Jalal

    2017-09-01

    Radiotherapy in patients with pelvis malignancy causes testes irradiation and resulted in testicular damages. Atorvastatin (ATV) in the low-dose is considered as antioxidant and anti-inflammatory properties. This experimental study was investigated protective effects of ATV on irradiation-induced testicular injury. Sixty male balb/c mice were randomly divided into 6 groups: 1: control, 2: irradiated (IR), 3, 4 and 5: IR plus ATV (10, 20 and 50mg/kg), 6: only ATV (50mg/kg). The ATV treated groups were received ATV for 7days via oral gavage before IR. Irradiated groups exposed to 2Gy whole body X-ray on day 8. Biochemical, histological and immunohistological parameters were evaluated for radioprotective effect of ATV. In the ATV pretreatment in irradiated mice, MDA levels were significantly decreased compared with the IR group. The effect of all three doses of ATV caused reduced MDA level, but ATV to dose of 50mg/kg had more effect than other doses of ATV. Significant decrease in the concentration of testosterone was observed in only irradiated mice compared with the ATV plus irradiated. In addition, the histological examination showed Johnsen Score in the IR group was lower compared to ATV pretreated groups. ATV significantly reduced caspase-3 immunoreactivity induced by irradiation. The results from this study suggest that ATV at low dose has a protective effect against irradiation-induced testicular damage. This result provides a new indication of ATV for protection of testis during radiation therapy in treatment of cancer patients. Copyright © 2017 Elsevier Inc. All rights reserved.

  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. Self-consistent solution of cosmological radiation-hydrodynamics and chemical ionization

    Science.gov (United States)

    Reynolds, Daniel R.; Hayes, John C.; Paschos, Pascal; Norman, Michael L.

    2009-10-01

    We consider a PDE system comprising compressible hydrodynamics, flux-limited diffusion radiation transport and chemical ionization kinetics in a cosmologically-expanding universe. Under an operator-split framework, the cosmological hydrodynamics equations are solved through the piecewise parabolic method, as implemented in the Enzo community hydrodynamics code. The remainder of the model, including radiation transport, chemical ionization kinetics, and gas energy feedback, form a stiff coupled PDE system, which we solve using a fully-implicit inexact Newton approach, and which forms the crux of this paper. The inner linear Newton systems are solved using a Schur complement formulation, and employ a multigrid-preconditioned conjugate gradient solver for the inner Schur systems. We describe this approach and provide results on a suite of test problems, demonstrating its accuracy, robustness, and scalability to very large problems.

  3. Occupational exposure to ionizing radiation from the perspective of nursing professionals in hemodynamics

    Directory of Open Access Journals (Sweden)

    Adriana Martins Gallo

    2013-05-01

    Full Text Available In order to identify the security measures taken and the control of occupational exposure to ionizing radiation in units of hemodynamic, from the perspective of nursing, this quantitative descriptive study was developed during January and February, 2011. A check-list of binary responses (yes / no was made based on the legislation and updated literature and it was applied in four hospitals in the northern region of Paraná State. The analysis of the data showed that 29 employees have knowledge about occupational exposure and apply barrier methods effectively to minimize doses of ionizing radiation. The data also showed that employees are participating in ongoing updating on the subject, and that they claim that this participation has a positive effect so that the occupational exposure occurs consciously, and also, the workers did not refuse to participate in any action facing their individual protection.

  4. 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.

  5. Quantitative Proteomic Profiling of Low Dose Ionizing Radiation Effects in a Human Skin Model

    Energy Technology Data Exchange (ETDEWEB)

    Hengel, Shawna; Aldrich, Joshua T.; Waters, Katrina M.; Pasa-Tolic, Ljiljana; Stenoien, David L.

    2014-07-29

    To assess molecular responses to low doses of radiation that may be encountered during medical diagnostic procedures, nuclear accidents, or terrorist acts, a quantitative global proteomic approach was used to identify protein alterations in a reconstituted human skin tissue treated with 10 cGy of ionizing radiation. Subcellular fractionation was employed to remove highly abundant structural proteins and provide insight on radiation induced alterations in protein abundance and localization. In addition, peptides were post-fractionated using high resolution 2-dimensional liquid chromatography to increase the dynamic range of detection of protein abundance and translocation changes. Quantitative data was obtained by labeling peptides with 8-plex isobaric iTRAQ tags. A total of 207 proteins were detected with statistically significant alterations in abundance and/or subcellular localization compared to sham irradiated tissues. Bioinformatics analysis of the data indicated that the top canonical pathways affected by low dose radiation are related to cellular metabolism. Among the proteins showing alterations in abundance, localization and proteolytic processing was the skin barrier protein filaggrin which is consistent with our previous observation that ionizing radiation alters profilaggrin processing with potential effects on skin barrier functions. In addition, a large number of proteases and protease regulators were affected by low dose radiation exposure indicating that altered proteolytic activity may be a hallmark of low dose radiation exposure. While several studies have demonstrated altered transcriptional regulation occurs following low dose radiation exposures, the data presented here indicates post-transcriptional regulation of protein abundance, localization, and proteolytic processing play an important role in regulating radiation responses in complex human tissues.

  6. 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

  7. 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)

  8. 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.

  9. Impact of ionizing radiation on physicochemical and biological properties of an amphiphilic macromolecule

    OpenAIRE

    Gu, Li; Zablocki, Kyle; Lavelle, Linda; Bodnar, Stanko; Halperin, Frederick; Harper, Ike; Moghe, Prabhas V.; Uhrich, Kathryn E.

    2012-01-01

    An amphiphilic macromolecule (AM) was exposed to ionizing radiation (both electron beam and gamma) at doses of 25 kGy and 50 kGy to study the impact of these sterilization methods on the physicochemical properties and bioactivity of the AM. Proton nuclear magnetic resonance and gel permeation chromatography were used to determine the chemical structure and molecular weight, respectively. Size and zeta potential of the micelles formed from AMs in aqueous media were evaluated by dynamic light s...

  10. Dwarf galaxies with ionizing radiation feedback. II. Spatially resolved star formation relation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji-hoon; Krumholz, Mark R.; Wise, John H.; Turk, Matthew J.; Goldbaum, Nathan J.; Abel, Tom

    2013-11-15

    AWe investigate the spatially resolved star formation relation using a galactic disk formed in a comprehensive high-resolution (3.8 pc) simulation. Our new implementation of stellar feedback includes ionizing radiation as well as supernova explosions, and we handle ionizing radiation by solving the radiative transfer equation rather than by a subgrid model. Photoheating by stellar radiation stabilizes gas against Jeans fragmentation, reducing the star formation rate (SFR). Because we have self-consistently calculated the location of ionized gas, we are able to make simulated, spatially resolved observations of star formation tracers, such as Hα emission. We can also observe how stellar feedback manifests itself in the correlation between ionized and molecular gas. Applying our techniques to the disk in a galactic halo of 2.3 × 1011 M , we find that the correlation between SFR density (estimated from mock Hα emission) and H2 density shows large scatter, especially at high resolutions of ≲ 75 pc that are comparable to the size of giant molecular clouds (GMCs). This is because an aperture of GMC size captures only particular stages of GMC evolution and because Hα traces hot gas around star-forming regions and is displaced from the H2 peaks themselves. By examining the evolving environment around star clusters, we speculate that the breakdown of the traditional star formation laws of the Kennicutt-Schmidt type at small scales is further aided by a combination of stars drifting from their birthplaces and molecular clouds being dispersed via stellar feedback.

  11. Analysis of Policy and Doctrine Supporting the Management of Operational Exposures to Ionizing Radiation

    Science.gov (United States)

    2016-06-01

    Health Protection program, and basic concepts of decontamination for patient movement.19 Field Manual (FM) 3-11 states “ Radiological hazards are an...Defense Planning & Response Project,” for the Joint Staff, Joint Requirements Office (JRO) for Chemical, Biological, Radiological and Nuclear (CBRN...on the medical management of radiological or nuclear casualties and operational exposure to ionizing radiation.”1 This document includes a review of

  12. 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.)

  13. 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)

  14. 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.

  15. Resource Letter EIRLD-2: Effects of Ionizing Radiation at Low Doses

    Science.gov (United States)

    Wilson, Richard

    2012-04-01

    This Resource Letter provides a guide to the literature on the effects of ionizing radiation on people at low doses. Journal articles, books and web pages are provided for the following: data at high dose levels, effects of moderate to high doses (leukemia, solid cancer, lung cancer, childhood cancer, and non-cancer outcomes), effects of dose rate, relationship to background, supra linearity and hormesis, and policy implications.

  16. In Vivo Optical Imaging of Tumor and Microvascular Response to Ionizing Radiation

    OpenAIRE

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

    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 smal...

  17. 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.

  18. Water Radiolysis: Influence of Oxide Surfaces on H2 Production under Ionizing Radiation

    Directory of Open Access Journals (Sweden)

    Sophie Le Caër

    2011-02-01

    Full Text Available The radiolysis of water due to ionizing radiation results in the production of electrons, H· atoms, ·OH radicals, H3O+ ions and molecules (dihydrogen H2 and hydrogen peroxide H2O2. A brief history of the development of the understanding of water radiolysis is presented, with a focus on the H2 production. This H2 production is strongly modified at oxide surfaces. Different parameters accounting for this behavior are presented.

  19. Statistical Assessement on Cancer Risks of Ionizing Radiation and Smoking Based on Poisson Models

    OpenAIRE

    Tomita, Makoto; Otake, Masanori

    2001-01-01

    In many epidemiological and medical studies, a number of cancer motralities in catagorical classification may be considered as having Poisson distribution with person-years at risk depending upon time. The cancer mortalities have been evaluated by additive or multiplicative models with regard to background and excess risks based on several covariances such as sex, age at the time of bombings, time at exposure, or ionizing radiation, cigarette smoking habits, duration of smoking habits, etc. A...

  20. Process and device for the regulation of operating conditions of a catalytic cracking reactor using an ionizing radiation source

    Energy Technology Data Exchange (ETDEWEB)

    Beretta, A.; Boute, B.; Pontier, R.

    1991-05-31

    An ionizing radiation source and a radiation detector allow, through a radiation absorption technique, the measurement of the in-motion solid mean density, perpendicularly to the charge migration axis. The density measurement allows the measure and control of the solid quantity and/or the fluid characteristics and/or the hydrocarbon charge.

  1. Silicone crosslinked by ionizing radiation as potential polymeric matrix for drug delivery

    Energy Technology Data Exchange (ETDEWEB)

    Rogero, Sizue O. [Chemistry and Environmental Centre, Nuclear Energy Research Institute, IPEN, Avenida Prof Lineu Prestes, 2242, Cep 05508-900, Cidade Universitaria, Sao Paulo, SP (Brazil)]. E-mail: sorogero@ipen.br; Sousa, Jose S. [Chemistry and Environmental Centre, Nuclear Energy Research Institute, IPEN, Avenida Prof Lineu Prestes, 2242, Cep 05508-900, Cidade Universitaria, Sao Paulo, SP (Brazil); Alario, Dante [Biolab Sanus Farmaceutica Ltda (Brazil); Lopergolo, Lilian [Biolab Sanus Farmaceutica Ltda (Brazil); Lugao, Ademar B. [Chemistry and Environmental Centre, Nuclear Energy Research Institute, IPEN, Avenida Prof Lineu Prestes, 2242, Cep 05508-900, Cidade Universitaria, Sao Paulo, SP (Brazil)

    2005-07-01

    This work describes the use of a catalysis-free system for crosslinking of silicone. Biomedical Grade silicone was crosslinked by ionizing radiation and the physico-chemical and biocompatibility properties of the resulting material were evaluated. High gel content (>90%) was obtained at the irradiation dose of 25 kGy, as indicated by gel fraction measurements. Swelling measurements showed a trend towards stabilization of crosslinking at 75 kGy. DMTA measurements showed that crystallization was impaired by the crosslinking reaction. The in vitro cytotoxicity data showed that radiation-induced crosslinking and degradation did not promote any toxicity in irradiated silicone.

  2. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. 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.

  4. Quantitative Proteomic Profiling of Low-Dose Ionizing Radiation Effects in a Human Skin Model

    Directory of Open Access Journals (Sweden)

    Shawna M. Hengel

    2014-07-01

    Full Text Available To assess responses to low-dose ionizing radiation (LD-IR exposures potentially encountered during medical diagnostic procedures, nuclear accidents or terrorist acts, a quantitative proteomic approach was used to identify changes in protein abundance in a reconstituted human skin tissue model treated with 0.1 Gy of ionizing radiation. To improve the dynamic range of the assay, subcellular fractionation was employed to remove highly abundant structural proteins and to provide insight into radiation-induced alterations in protein localization. Relative peptide quantification across cellular fractions, control and irradiated samples was performing using 8-plex iTRAQ labeling followed by online two-dimensional nano-scale liquid chromatography and high resolution MS/MS analysis. A total of 107 proteins were detected with statistically significant radiation-induced change in abundance (>1.5 fold and/or subcellular localization compared to controls. The top biological pathways identified using bioinformatics include organ development, anatomical structure formation and the regulation of actin cytoskeleton. From the proteomic data, a change in proteolytic processing and subcellular localization of the skin barrier protein, filaggrin, was identified, and the results were confirmed by western blotting. This data indicate post-transcriptional regulation of protein abundance, localization and proteolytic processing playing an important role in regulating radiation response in human tissues.

  5. 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.

  6. 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.

  7. Diversity of ionizing radiation-resistant bacteria obtained from the Taklimakan Desert.

    Science.gov (United States)

    Yu, Li Zhi-Han; Luo, Xue-Song; Liu, Ming; Huang, Qiaoyun

    2015-01-01

    So far, little is known about the diversity of the radiation-resistant microbes of the hyperarid Taklimakan Desert. In this study, ionizing radiation (IR)-resistant bacteria from two sites in Xinjiang were investigated. After exposing the arid (water content of 0.8 ± 0.3%) and non-arid (water content of 21.3 ± 0.9%) sediment samples to IR of 3000 Gy using a (60)Co source, a total of 52 γ-radiation-resistant bacteria were isolated from the desert sample. The 16S rRNA genes of all isolates were sequenced. The phylogenetic tree places these isolates into five groups: Cytophaga-Flavobacterium-Bacteroides, Proteobacteria, Deinococcus-Thermus, Firmicutes, and Actinobacteria. Interestingly, this is the first report of radiation-resistant bacteria belonging to the genera Knoellia, Lysobacter, Nocardioides, Paracoccus, Pontibacter, Rufibacter and Microvirga. The 16s rRNA genes of four isolates showed low sequence similarities to those of the published species. Phenotypic analysis showed that all bacteria in this study are able to produce catalase, suggesting that these bacteria possess reactive oxygen species (ROS)-scavenging enzymes. These radiation-resistant bacteria also displayed diverse metabolic properties. Moreover, their radiation resistances were found to differ. The diversity of the radiation-resistant bacteria in the desert provides further ecological support for the hypothesis that the ionizing-radiation resistance phenotype is a consequence of the evolution of ROS-scavenging systems that protect cells against oxidative damage caused by desiccation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Are the urology operating room personnel aware about the ionizing radiation?

    Science.gov (United States)

    Tok, Adem; Akbas, Alparslan; Aytan, Nimet; Aliskan, Tamer; Cicekbilek, Izzet; Kaba, Mehmet; Tepeler, Abdulkadir

    2015-01-01

    ABSTRACT Purpose: We assessed and evaluated attitudes and knowledge regarding ionizing radiation of urology surgery room staff. Materials and Methods: A questionnaire was sent by e-mail to urology surgery room personnel in Turkey, between June and August 2013. The questionnaire included demographic questions and questions regarding radiation exposure and protection. Results: In total, 127 questionnaires were answered. Of them, 62 (48.8%) were nurses, 51 (40.2%) were other personnel, and 14 (11%) were radiological technicians. In total, 113 (89%) participants had some knowledge of radiation, but only 56 (44.1%) had received specific education or training regarding the harmful effects of radiation. In total, 92 (72.4%) participants indicated that they used a lead apron and a thyroid shield. In the subgroup that had received education about the harmful effects of radiation, the use ratio for all protective procedures was 21.4% (n=12); this ratio was only 2.8% (n=2) for those with no specific training; the difference was statistically significant (p=0.004). Regarding dosimeters, the use rates were 100% for radiology technicians, 46.8% for nurses, and 31.4% for other hospital personnel; these differences were statistically significant (p<0.001). No significant relationship between working period in the surgery room, number of daily fluoroscopy procedures, education, task, and use of radiation protection measures was found. Conclusions: It is clear that operating room-allied health personnel exposed to radiation do not have sufficient knowledge of ionizing radiation and they do not take sufficient protective measures. PMID:26689525

  9. Are the urology operating room personnel aware about the ionizing radiation?

    Directory of Open Access Journals (Sweden)

    Adem Tok

    2015-10-01

    Full Text Available ABSTRACT Purpose: We assessed and evaluated attitudes and knowledge regarding ionizing radiation of urology surgery room staff. Materials and Methods: A questionnaire was sent by e-mail to urology surgery room personnel in Turkey, between June and August 2013. The questionnaire included demographic questions and questions regarding radiation exposure and protection. Results: In total, 127 questionnaires were answered. Of them, 62 (48.8% were nurses, 51 (40.2% were other personnel, and 14 (11% were radiological technicians. In total, 113 (89% participants had some knowledge of radiation, but only 56 (44.1% had received specific education or training regarding the harmful effects of radiation. In total, 92 (72.4% participants indicated that they used a lead apron and a thyroid shield. In the subgroup that had received education about the harmful effects of radiation, the use ratio for all protective procedures was 21.4% (n=12; this ratio was only 2.8% (n=2 for those with no specific training; the difference was statistically significant (p=0.004. Regarding dosimeters, the use rates were 100% for radiology technicians, 46.8% for nurses, and 31.4% for other hospital personnel; these differences were statistically significant (p<0.001. No significant relationship between working period in the surgery room, number of daily fluoroscopy procedures, education, task, and use of radiation protection measures was found. Conclusions: It is clear that operating room-allied health personnel exposed to radiation do not have sufficient knowledge of ionizing radiation and they do not take sufficient protective measures.

  10. Beneficial effects of cellular autofluorescence following ionization radiation: hypothetical approaches for radiation protection and enhancing radiotherapy effectiveness.

    Science.gov (United States)

    Abdollahi, Hamid

    2015-03-01

    Ionization radiation (IR) is a main part of modern technologies with a double-edge sword manner. Finding the most feasible therapies to reduce adverse effects of IR and also enhancing radiotherapy effectiveness is a debating issue that has been challenged and studied for years. The main aim of the present hypothetical research was to theorize and suggest a new biological radiation protection approach and also increasing radiotherapy outcomes based on cellular autofluorescence following IR. In this hypothesis, we suggested that this cellular autofluorescence can activate some synthetic drugs called photo-activated agents that are injected in human body after radiation exposures scenarios. Photo activated agents can activate biological pathways such as DNA repair and immunostimulation pathways, bystander signals blocking, and so survive cells and tissues. In the other hand, light emitted by cellular response to radiation can be used as like as photodynamic therapy and therefore more cancer cells killing via apoptosis and necrosis. These ideas can be performed in future using more animal and in vivo/in vitro studies and clinical trials. In conclusion, cellular autofluorescence after radiation exposure can be used as a source for activation specific drugs for radiation protection and also radiation therapy effectiveness. These hypothetical therapeutic approaches can be served as personalized therapy based on individual radiosensitivity. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. 76 FR 4944 - Ionizing Radiation Standard; Extension of the Office of Management and Budget's (OMB) Approval of...

    Science.gov (United States)

    2011-01-27

    ... may result from occupational exposure to ionizing radiation including tissue damage and cancer. DATES... information such as Social Security numbers and date of birth. Although all submissions are listed in the http...

  12. Atmospheric Ionizing Radiation (AIR): Analysis, Results, and Lessons Learned From the June 1997 ER-2 Campaign

    Science.gov (United States)

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

    2003-01-01

    The United States initiated a program to assess the technology required for an environmentally safe and operationally efficient High Speed Civil Transport (HSCT) for entrance on the world market after the turn of the century. Due to the changing regulations on radiation exposures and the growing concerns over uncertainty in our knowledge of atmospheric radiations, the NASA High Speed Research Project Office (HSRPO) commissioned a review of "Radiation Exposure and High-Altitude Flight" by the National Council on Radiation Protection and Measurements (NCRP). On the basis of the NCRP recommendations, the HSRPO funded a flight experiment to resolve the environmental uncertainty in the atmospheric ionizing radiation levels as a step in developing an approach to minimize the radiation impact on HSCT operations. To minimize costs in this project, an international investigator approach was taken to assure coverage with instrument sensitivity across the range of particle types and energies to allow unique characterization of the diverse radiation components. The present workshop is a result of the flight measurements made at the maximum intensity of the solar cycle modulated background radiation levels during the month of June 1997.

  13. 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.

  14. Use of Biomphalaria glabrata hemocytes as a biomarker of exposure to ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Hianna A.M.F.; Lima, Maira V.; Sa, Jose L.F.; Siqueira, Williams N.; Luna Filho, Ricardo L.C.; Melo, Larissa S.A.; Morais, Vinicius H.T.; Melo, Ana M.M.A., E-mail: hiannaamfs@gmail.com, E-mail: mairavasconceloslima@gmail.com, E-mail: luismuma6@gmail.com, E-mail: williams.wns@gmail.com, E-mail: ricardolclf@hotmail.com, E-mail: larissamelo.pe@gmail.com, E-mail: viniciushtmorais@hotmail.com, E-mail: amdemelo@hotmail.com [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Biofisica e Radiobiologia

    2017-11-01

    The increase of the applications of ionizing radiation in several areas and sectors of modern society has given rise to a greater probability of occurrence of accidents. These accidental occurrences have revealed the need for methods that provide quantitative data on the radiation doses absorbed by biological systems. The mollusk Biomphalaria glabrata presents as a good bioindicator in several works referenced in the literature. In this way, the objective of this work was to evaluate the morphological and quantitative alterations of hemocytes of the Biomphalaria glabrata exposed to ionizing radiation. For the experiments, adult mollusks of the species B. glabrata pigmented were used. The selected mollusks were divided into six groups: five submitted to doses of 10, 20, 30, 40, 50 Gy of {sup 60}Co gamma radiation and the control group. After 48 h, the slides were prepared and then read in a microscope. Quantitative analysis showed a decrease in the total number of hemocytes after irradiation. In the cell classification, a higher number of hyalinocytes were observed in relation to the number of granulocytes, except for the animals exposed to a dose of 30 Gy. The presence of micronuclei and binucleations were observed at all doses used. Apoptosis was observed at doses starting at 30 Gy. Therefore, it is possible to conclude that the morphological and quantitative analysis of B. glabrata hemocytes provided significant data for the identification of biological damage caused by ionizing radiation, allowing the beginning of standardization of the morphological alteration counting technique in B. glabrata hemocytes as An environmental biomarker for the action of physical agents. (author)

  15. Response of Phaseolus vulgaris L. plants to low-let ionizing radiation: Growth and oxidative stress

    Science.gov (United States)

    Arena, C.; De Micco, V.; Aronne, G.; Pugliese, M.; Virzo De Santo, A.; De Maio, A.

    2013-10-01

    The scenarios for the long-term habitation of space platforms and planetary stations involve plants as fundamental part of Bioregenerative Life Support Systems (BLSS) to support the crew needs. Several constraints may limit plant growth in space: among them ionizing radiation is recognized to severely affect plant cell at morphological, physiological and biochemical level. In this work, plants of Phaseolus vulgaris L. were subjected to four different doses of X-rays (0.3, 10, 50 and 100 Gy) in order to assess the effects of ionizing radiation on this species and to analyze possible mechanisms carried out to overcome the radiation injuries. The effects of X-rays on plant growth were assessed by measuring stem elongation, number of internodes and leaf dry weight. The integrity of photosynthetic apparatus was evaluated by photosynthetic pigment composition and ribulose 1,5-bisphosphate carboxylase (Rubisco) activity, whereas changes in total antioxidant pool and glutathione S transferase activity (GST) were utilized as markers of oxidative stress. The distribution of phenolic compounds in leaf tissues as natural shielding against radiation was also determined. Irradiation of plants at 0.3 and 10 Gy did not determine differences in all considered parameters as compared to control. On the contrary, at 50 and 100 Gy a reduction of plant growth and a decrease in photosynthetic pigment content, as well as an increase in phenolic compounds and a decrease in total antioxidant content and GST activity were found. Only a slight reduction of Rubisco activity in leaves irradiated at 50 and 100 Gy was found. The overall results indicate P. vulgaris as a species with a good potential to face ionizing radiation and suggest its suitability for utilization in BLSSs.

  16. 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.

  17. 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.

  18. Hafnium-doped hydroxyapatite nanoparticles with ionizing radiation for lung cancer treatment.

    Science.gov (United States)

    Chen, Min-Hua; Hanagata, Nobutaka; Ikoma, Toshiyuki; Huang, Jian-Yuan; Li, Keng-Yuan; Lin, Chun-Pin; Lin, Feng-Huei

    2016-06-01

    Recently, photodynamic therapy (PDT) is one of the new clinical options by generating cytotoxic reactive oxygen species (ROS) to kill cancer cells. However, the optical approach of PDT is limited by tissue penetration depth of visible light. In this study, we propose that a ROS-enhanced nanoparticle, hafnium-doped hydroxyapatite (Hf:HAp), which is a material to yield large quantities of ROS inside the cells when the nanoparticles are bombarded with high penetrating power of ionizing radiation. Hf:HAp nanoparticles are generated by wet chemical precipitation with total doping concentration of 15mol% Hf(4+) relative to Ca(2+) in HAp host material. The results show that the HAp particles could be successfully doped with Hf ions, resulted in the formation of nano-sized rod-like shape and with pH-dependent solubility. The impact of ionizing radiation on Hf:HAp nanoparticles is assessed by using in-vitro and in-vivo model using A549 cell line. The 2',7'-dichlorofluorescein diacetate (DCFH-DA) results reveal that after being exposed to gamma rays, Hf:HAp could significantly lead to the formation of ROS in cells. Both cell viability (WST-1) and cytotoxicity (LDH) assay show the consistent results that A549 lung cancer cell lines are damaged with changes in the cells' ROS level. The in-vivo studies further demonstrate that the tumor growth is inhibited owing to the cells apoptosis when Hf:HAp nanoparticles are bombarded with ionizing radiation. This finding offer a new therapeutic method of interacting with ionizing radiation and demonstrate the potential of Hf:HAp nanoparticles in tumor treatment, such as being used in a palliative treatment after lung surgical procedure. Photodynamic therapy (PDT) is one of the new clinical options by generating cytotoxic reactive oxygen species (ROS) to kill cancer cells. Unfortunately, the approach of PDT is usually limited to the treatment of systemic disease and deeper tumor, due to the limited tissue penetration depth of visible

  19. Discussion of the combined effect of weightlessness and ionizing radiation on the mammalian body: morphological data. [Gamma radiation, rats

    Energy Technology Data Exchange (ETDEWEB)

    Portugalov, V.V.; Savina, E.A.; Kaplanskii, A.S.; Yakovleva, V.I.; Durnova, G.N.; Pankova, A.S.; Shvets, V.N.; Alekseev, E.I.; Katunyan, P.I.

    1977-01-01

    The combined effect of weightlessness and ionizing radiation, from the /sup 137/Cs source at 800 rads for 24 h, on the animal body was studied. The morphological examination of organs and tissues of rats flown aboard the biosatellite Cosmos-690, kept in the ground-based simulation experiment, and kept in the vivarium, indicated prevalence of radiation-induced changes in both experimental groups of rats. An exposure of animals to space flight factors did not produce a substantial aggravation of radiation-induced effects. This is indicated by the lack of significant differences in the weight of testes, thymus, and spleen of flight and simulation rats. However, this exposure affected adversely the development of reparative processes in the hemopoietic tissue of bone marrow. Inflight irradiation aggravated weightlessness-induced changes. A combined effect of weightlessness and irradiation did not result in the summation of the effects exerted on skeletal muscles by either factor alone.

  20. 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)

  1. Effects of ionizing radiation on the blood brain barrier permeability to pharmacologically active substances

    Energy Technology Data Exchange (ETDEWEB)

    Trnovec, T.; Kallay, Z.; Bezek, S. (Institute of Experimental Pharmacology, Bratislava (Yugoslavia))

    1990-12-01

    Ionizing radiation can impair the integrity of the blood brain barrier (BBB). Data on early and late damage after brain irradiation are usually reported separately, yet a gradual transition between these two types has become evident. Signs appearing within 3 weeks after irradiation are considered to be early manifestations. The mechanism of radiation-effected integrity impairment of the BBB is discussed in relation to changes in morphological structures forming the BBB, the endothelium of intracerebral vessels, and in the surrounding astrocytes. Alterations in the function of the BBB are manifested in the endothelium by changes in the ultrastructural location of the activity of phosphatases and by the activation of pinocytotic vesicular transport, and in astrocyte cytoplasm by glycogen deposition. The changes in ultrastructure were critically surveyed with regard to increasing doses of radiation to the brain in the range of 5 Gy to 960 Gy. The qualitative as well as the semiquantitative and quantitative observations on the passage of substances across the damaged BBB were treated separately. Qualitative changes are based mainly on findings of extravasation of vital stains and of labelled proteins. The quantitative studies established differences in radiation-induced changes in the permeability of the BBB depending on the structure and physico-chemical properties of the barrier penetrating tracers. Indirect evaluation of radiation-induced BBB changes is based on studies of pharmacological effects of substances acting on the CNS. In conclusion, radiation impairs significantly the integrity of the BBB following single irradiation of the brain with a dose exceeding 10-15 Gy. The response of the BBB to ionizing radiation is dependent both on the dose to which the brain is exposed and on specific properties of the tracer. 68 references.

  2. Intercellular Communication of Tumor Cells and Immune Cells after Exposure to Different Ionizing Radiation Qualities

    Directory of Open Access Journals (Sweden)

    Sebastian Diegeler

    2017-06-01

    Full Text Available Ionizing radiation can affect the immune system in many ways. Depending on the situation, the whole body or parts of the body can be acutely or chronically exposed to different radiation qualities. In tumor radiotherapy, a fractionated exposure of the tumor (and surrounding tissues is applied to kill the tumor cells. Currently, mostly photons, and also electrons, neutrons, protons, and heavier particles such as carbon ions, are used in radiotherapy. Tumor elimination can be supported by an effective immune response. In recent years, much progress has been achieved in the understanding of basic interactions between the irradiated tumor and the immune system. Here, direct and indirect effects of radiation on immune cells have to be considered. Lymphocytes for example are known to be highly radiosensitive. One important factor in indirect interactions is the radiation-induced bystander effect which can be initiated in unexposed cells by expression of cytokines of the irradiated cells and by direct exchange of molecules via gap junctions. In this review, we summarize the current knowledge about the indirect effects observed after exposure to different radiation qualities. The different immune cell populations important for the tumor immune response are natural killer cells, dendritic cells, and CD8+ cytotoxic T-cells. In vitro and in vivo studies have revealed the modulation of their functions due to ionizing radiation exposure of tumor cells. After radiation exposure, cytokines are produced by exposed tumor and immune cells and a modulated expression profile has also been observed in bystander immune cells. Release of damage-associated molecular patterns by irradiated tumor cells is another factor in immune activation. In conclusion, both immune-activating and -suppressing effects can occur. Enhancing or inhibiting these effects, respectively, could contribute to modified tumor cell killing after radiotherapy.

  3. Effects of ionizing radiation and preservation on biomechanical properties of human costal cartilage.

    Science.gov (United States)

    Martinho, A C; Rosifini Alves-Claro, A P; Pino, E S; Machado, L D B; Herson, M R; Santin, S P; Mathor, M B

    2013-03-01

    Tissue banks around the world store human cartilage obtained from cadaveric donors for use in diverse reconstructive surgical procedures. To ensure this tissue is sterile at the time of distribution, tissues may be sterilized by ionizing radiation. In this work, we evaluate the physical changes in deep frozen costal cartilage (-70 °C) or costal cartilage preserved in high concentrations of glycerol (>98 %) followed by a terminal sterilization process using ionizing radiation, at 3 different doses (15, 25 and 50 kGy). Tension and compression tests were carried out to determine the mechanical changes related both to the different preservation methods and irradiation doses. For both methods of preservation, tension strength was increased by about 24 %, when cartilage tissue was irradiated with 15 kGy. Deep frozen samples, when irradiated with 25 or 50 kGy, had a decrease in their mechanical performance, albeit to a lesser extent than when tissues were preserved in high concentration of glycerol and equally irradiated. In conclusion, processing in high concentration of glycerol did not increase tissue protection against radiation damage; while cartilage preserved in high concentrations of glycerol withstands radiation up to 25 kGy, deep frozen human costal cartilage may be sterilized with a doses up to 50 kGy without significant mechanical impact.

  4. Transcriptional analysis of Deinococcus radiodurans reveals novel small RNAs that are differentially expressed under ionizing radiation.

    Science.gov (United States)

    Tsai, Chen-Hsun; Liao, Rick; Chou, Brendan; Contreras, Lydia M

    2015-03-01

    Small noncoding RNAs (sRNAs) are posttranscriptional regulators that have been identified in multiple species and shown to play essential roles in responsive mechanisms to environmental stresses. The natural ability of specific bacteria to resist high levels of radiation has been of high interest to mechanistic studies of DNA repair and biomolecular protection. Deinococcus radiodurans is a model extremophile for radiation studies that can survive doses of ionizing radiation of >12,000 Gy, 3,000 times higher than for most vertebrates. Few studies have investigated posttranscriptional regulatory mechanisms of this organism that could be relevant in its general gene regulatory patterns. In this study, we identified 199 potential sRNA candidates in D. radiodurans by whole-transcriptome deep sequencing analysis and confirmed the expression of 41 sRNAs by Northern blotting and reverse transcriptase PCR (RT-PCR). A total of 8 confirmed sRNAs showed differential expression during recovery after acute ionizing radiation (15 kGy). We have also found and confirmed 7 sRNAs in Deinococcus geothermalis, a closely related radioresistant species. The identification of several novel sRNAs in Deinococcus bacteria raises important questions about the evolution and nature of global gene regulation in radioresistance. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  5. 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)

  6. 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.

  7. 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.

  8. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Hemperek, Tomasz; Kishishita, Tetsuichi; Krueger, Hans; Wermes, Norbert [Institute of Physics, University of Bonn, Bonn (Germany)

    2016-07-01

    An improved SOI-MAPS (Silicon On Insulator Monolithic Active Pixel Sensor) for ionizing radiation based on thick-180 nm 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. Standard FD-SOI MAPS suffer from radiation damage such as transistor threshold voltage shifts due to trapped charge in the buried oxide layer and charged interface states created at the silicon oxide boundaries (back gate effect). The X-FAB 180 nm HV-SOI technology offers an additional isolation using a 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. The design and measurement results from first prototypes are presented including radiation tolerance to total ionizing dose and charge collection properties of neutron irradiated samples.

  10. Study of interaction of low doses of ionizing radiation with selected pesticides on Artemia franciscana

    Directory of Open Access Journals (Sweden)

    Michaela Špalková

    2015-01-01

    Full Text Available The aim of our study was to observe the effect of low doses of ionizing radiation, azoxystrobin and glyphosate separately as well as in their mutual combinations on the lethality of Artemia franciscana. Increasing intensity of agricultural production leads to continual exposure of animals to pesticide residues. Animals could be exposed to these negative factors in case of possible nuclear accident. A total of 1000 nauplia, randomly placed in 20 groups (1 control and 19 experimental groups, were irradiated with gamma rays (0, 20, 30, 40 or 50 Gy and were kept in solution of standardized sea water and standardized sea water with addition of pesticides (azoxystrobin at a concentration of 0.0001 g·l-1 and glyphosate at a concentration of 0.5 g·l-1 individually or in combination. A significant increase of lethality was observed after 48, 72 and 96 h of exposure to only azoxystrobin, but also in the group exposed to the combined effect of azoxystrobin and glyphosate at all time intervals. On the other hand, a significant decrease of lethality was observed in those groups exposed to ionizing radiation even at the dose of 30 Gy at all time intervals compared to non-irradiated groups. These results confirm the toxicity of azoxystrobin to aquatic organisms; non-toxicity of glyphosate to crustaceans and support the theory of radiation hormesis at the level of 30 Gy radiation dose.

  11. c-jun gene expression in human cells exposed to either ionizing radiation or hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Collart, F.R.; Horio, M.; Huberman, E.

    1993-06-01

    We investigated the role of reactive oxygen intermediates (ROIs) and protein kinase C (PKC) in radiation- and H{sub 2}O{sub 2}-evoked c-jun gene expression in human HL-205 cells. This induction of c-jun gene expression could be prevented by pretreatment of the cells with Nacetylcysteine (an antioxidant) or H7 (a PKC and PKA inhibitor) but not by HA1004, a PKA inhibitor, suggesting a role for ROls and PKC in mediating c-jun gene expression. We also investigated potential differences in c-jun gene expression in a panel of normal and tumor cells untreated or treated with ionizing radiation or H{sub 2}O{sub 2}. Treatment with radiation or H{sub 2}O{sub 2} produced a varied response, from some reduction to an increase of more than an order of magnitude in the steady-state level of c-jun mRNA. These data indicate that although induction of c-jun may be a common response to ionizing radiation and H{sub 2}O{sub 2}, this response was reduced or absent in some cell types.

  12. How protective are the lead aprons we use against ionizing radiation?

    Science.gov (United States)

    Oyar, Orhan; Kışlalıoğlu, Arzu

    2012-01-01

    To evaluate, in terms of their protective features, the lead aprons used in areas working with ionizing radiation at a hospital by analyzing qualitative and quantitative aspects using a variety of methods. Eighty-five protective lead aprons used in our hospital's clinics to work with ionizing radiation were analyzed in the radiology unit. Each apron was identified by registering the unit from which it had been obtained and by how long it had been used, its storage condition, and its lead thickness. X-ray films of the aprons, controlled according to their appearances, durability and cleanliness, were taken to evaluate their internal structure; their permeability was measured with electronic dosimeters in terms of their absorbent features. All of these data were compared with the results acquired from brand-new, Turkish Standards Institution approved aprons having different lead thicknesses. Regarding internal structure homogeneity, only 13 (15.3%) of 85 aprons were found to be at normal levels and usable. A total of 14 (16.5%) of the remaining 72 aprons' radiation absorptions were at normal levels, but folds were observed in their protective lead layers. The remaining 58 aprons (68.2%) were found to be defective. All of the aprons were considered to be defective in terms of their radiation permeability. All of the aprons were found insufficient for protection and were more radioparent than the defined limits; it was concluded that they must be replaced by new ones.

  13. Population sensitivities of animals to chronic ionizing radiation-model predictions from mice to elephant.

    Science.gov (United States)

    Sazykina, Tatiana G

    2018-02-01

    Model predictions of population response to chronic ionizing radiation (endpoint 'morbidity') were made for 11 species of warm-blooded animals, differing in body mass and lifespan - from mice to elephant. Predictions were made also for 3 bird species (duck, pigeon, and house sparrow). Calculations were based on analytical solutions of the mathematical model, simulating a population response to low-LET ionizing radiation in an ecosystem with a limiting resource (Sazykina, Kryshev, 2016). Model parameters for different species were taken from biological and radioecological databases; allometric relationships were employed for estimating some parameter values. As a threshold of decreased health status in exposed populations ('health threshold'), a 10% reduction in self-repairing capacity of organisms was suggested, associated with a decline in ability to sustain environmental stresses. Results of the modeling demonstrate a general increase of population vulnerability to ionizing radiation in animal species of larger size and longevity. Populations of small widespread species (mice, house sparrow; body mass 20-50 g), which are characterized by intensive metabolism and short lifespan, have calculated 'health thresholds' at dose rates about 6.5-7.5 mGy day -1 . Widespread animals with body mass 200-500 g (rat, common pigeon) - demonstrate 'health threshold' values at 4-5 mGy day -1 . For populations of animals with body mass 2-5 kg (rabbit, fox, raccoon), the indicators of 10% health decrease are in the range 2-3.4 mGy day -1 . For animals with body mass 40-100 kg (wolf, sheep, wild boar), thresholds are within 0.5-0.8 mGy day -1 ; for herbivorous animals with body mass 200-300 kg (deer, horse) - 0.5-0.6 mGy day -1 . The lowest health threshold was estimated for elephant (body mass around 5000 kg) - 0.1 mGy day -1 . According to the model results, the differences in population sensitivities of warm-blooded animal species to ionizing radiation are generally

  14. 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

  15. 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)

  16. Reductions in calcium uptake induced in rat brain synaptosomes by ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kandasamy, S.B.; Howerton, T.C.; Hunt, W.A. (Armed Forces Radiobiology Research Institute, Bethesda, MD (USA))

    1991-02-01

    Gamma irradiation (60Co) reduced KCl-stimulated voltage-dependent 45Ca2+ uptake in whole-brain, cortical, and striatal synaptosomes. The time course (3, 10, 30, and 60 s) of calcium uptake by irradiated (3 Gy) and nonirradiated synaptosomes, as well as the effect of KCl (15-65 mM), was measured in whole-brain synaptosomes. The fastest and highest rate of depolarization-dependent calcium uptake occurred at 3 s with 65 mM KCl. Irradiation reduced calcium uptake at all incubation times and KCl concentrations. Bay K 8644 enhancement of KCl-stimulated calcium influx was also reduced by radiation exposure. Nimodipine binding to dihydropyridine (DHP) L-type calcium channel receptors was not altered following radiation exposure. These results demonstrate an inhibitory effect of ionizing radiation on the voltage-sensitive calcium channels in rat brain synaptosomes that are not mediated by DHP receptors.

  17. Analysis of texture in baby carrot (Daucus carota) subjected to the process of ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Nunes, Thaise C.F.; Rogovschi, Vladimir D.; Fabbri, Adriana D.T.; Sagretti, Juliana M.A.; Sabato, Susy F., E-mail: ssabato@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    The carrot is a vegetable of great economic value due to its versatility in the food industry and can be used as raw or minimally processed vegetable or aggregating value to the product, transforming the fresh carrots in baby carrots. It is well known that the application of gamma radiation in food may help in maintaining the quality of food. The aim of this study was to analyze the effects of the low doses of ionizing radiation on texture of minimally processed baby carrot after the processing in a Multipurpose {sup 60}Co irradiator. It can be concluded that the treatment with low doses of gamma radiation keep the quality of fresh-cut baby carrot. (author)

  18. Investigation of ionizing radiation shielding effectiveness of decorative building materials used in Bangladeshi dwellings

    Science.gov (United States)

    Yesmin, Sabina; Sonker Barua, Bijoy; Uddin Khandaker, Mayeen; Tareque Chowdhury, Mohammed; Kamal, Masud; Rashid, M. A.; Miah, M. M. H.; Bradley, D. A.

    2017-11-01

    Following the rapid growing per capita income, a major portion of Bangladeshi dwellers is upgrading their non-brick houses by rod-cement-concrete materials and simultaneously curious to decorate the houses using luxurious marble stones. Present study was undertaken to investigate the gamma-ray attenuation co-efficient of decorative marble materials leading to their suitability as shielding of ionizing radiation. A number of commercial grades decorative marble stones were collected from home and abroad following their large-scale uses. A well-shielded HPGe γ-ray spectrometer combined with associated electronics was used to evaluate the mass attenuation coefficients of the studied materials for high energy photons. Some allied parameters such as half-value layer and radiation protection efficacy of the investigated marbles were calculated. The results showed that among the studied samples, the marble 'Carrara' imported from Italy is suitable to be used as radiation shielding material.

  19. 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.

  20. 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.

  1. 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.

  2. A History of the International Commission on Non-Ionizing Radiation Protection.

    Science.gov (United States)

    Repacholi, M H

    2017-10-01

    Concern about health risks from exposure to non-ionizing radiation (NIR) commenced in the 1950s after tracking radars were first introduced during the Second World War. Soon after, research on possible biological effects of microwave radiation in the former Soviet Union and the U.S. led to public and worker exposure limits being much lower in Eastern European than in Western countries, mainly because of different protection philosophies. As public concern increased, national authorities began introducing legislation to limit NIR exposures from domestic microwave ovens and workplace devices such as visual display units. The International Radiation Protection Association (IRPA) was formed in 1966 to represent national radiation protection societies. To address NIR protection issues, IRPA established a Working Group in 1974, then a Study Group in 1975, and finally the International NIR Committee (INIRC) in 1977. INIRC's publications quickly became accepted worldwide, and it was logical that it should become an independent commission. IRPA finally established the International Commission on Non-Ionizing Radiation Protection (ICNIRP), chartering its remit in 1992, and defining NIR as electromagnetic radiation (ultraviolet, visible, infrared), electromagnetic waves and fields, and infra- and ultrasound. ICNIRP's guidelines have been incorporated into legislation or adopted as standards in many countries. While ICNIRP has been subjected to criticism and close scrutiny by the public, media, and activists, it has continued to issue well-received, independent, science-based protection advice. This paper summarizes events leading to the formation of ICNIRP, its key activities up to 2017, ICNIRP's 25th anniversary year, and its future challenges.

  3. Exposure to Low-Dose Ionizing Radiation from Medical Imaging Procedures in the United States

    Science.gov (United States)

    Fazel, Reza; Krumholz, Harlan M.; Wang, Yongfei; Ross, Joseph S.; Chen, Jersey; Ting, Henry H.; Shah, Nilay D.; Nasir, Khurram; Einstein, Andrew J.; Nallamothu, Brahmajee K.

    2013-01-01

    Background Growing use of imaging procedures in the United States has raised concerns about exposure to low-dose ionizing radiation in the general population. Methods We identified 952,420 non-elderly adults in 5 healthcare markets across the United States between July 1, 2005 and December 31, 2007. Utilization data were used to determine cumulative effective doses of radiation from imaging procedures in millisieverts (mSv) and to calculate population-based rates of “moderate” (>3 to 20 mSv per year), “high” (>20 to 50 mSv per year) and “very-high” (>50 mSv per year) doses. Results During the study period, 655,613 (68.8%) individuals underwent at least 1 imaging procedure associated with radiation exposure. The mean effective dose from imaging procedures was 2.4 mSv per person per year (std dev, 6.0 mSv); however, a wide distribution was noted with a median effective dose of 0.1 mSv per person per year (interquartile range, 0.0 to 1.7). Overall, the annual rate for moderate effective doses in the study population was 193.8 per 1000 enrollees, while high and very-high doses occurred at annual rates of 18.6 per 1000 enrollees and 1.9 per 1000 enrollees, respectively. In general, effective doses of radiation from imaging procedures increased with advancing age and were higher in women. Computed tomography and nuclear medicine scans accounted for 75.4% of the total effective dose and 81.8% occurred in non-hospitalized settings. Conclusions Imaging procedures are an important source of ionizing radiation in the United States and can lead to high radiation doses in patients. PMID:19710483

  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. In vitro evaluation of ionizing radiation effects in bone tissue by FTIR spectroscopy

    Science.gov (United States)

    Zezell, Denise Maria; Veloso, Marcelo Noronha; Dias, Derly Augusto; Politano, Rodolfo; Benetti, Carolina

    2015-06-01

    We verified the changes promoted by ionizing radiation in bone tissue using FTIR. Samples of bovine bone were irradiated using Cobalt-60 with 0.01kGy, 0.1kGy, 1kGy, 15kGy and 75kGy. The effects of ionizing irradiation on chemical structure of bone, were studied considering the sub-bands of amide I, the crystallinity index and relation of organic and inorganic materials. ATR-FTIR spectroscopy showed changes in organic components and in hydroxyapatite crystals organization. High correlation with statistical significance was observed between (amideIII+collagen)/ ν1,ν3PO4, crystallinity and mechanical properties of the samples.

  6. Liver late effects of ionizing radiation; Effets tardifs des radiations sur le foie

    Energy Technology Data Exchange (ETDEWEB)

    Mornex, F.; Ramuz, O. [Centre Hospitalier Universitaire Lyon-Sud, 69 - Pierre-Benite (France); Gerard, F. [Laboratoire Marcel-Merieux, 69 - Lyon (France); Van Houtte, P. [Institut Bordet, Brussels (Belgium)

    1997-12-01

    Until recently, the liver was classified as a radioresistant organ, although it is in fact highly radiosensitive. The realization that the whole liver could be treated safety only with low doses of radiation led to the conclusion that radiation therapy had an extremely limited role in the treatment of intrahepatic malignancies. A resurgence of interest has been observed with the advent of conformal radiotherapy and the introduction of bone marrow transplantation with total body irradiation. The radiation-induced liver disease, often called radiation hepatitis, is a syndrome characterized by the development of anicteric ascites, approximately 2 weeks to 4 months after hepatic irradiation. Immediate tolerance is generally surprisingly good, and the subacute radiation injury is followed by a complete asymptomatic healing, although the late lesions may be associated with signs of chronic radiation hepatitis. Radiation hepatitis must be distinguished from chemo-radiation-induced-hepatitis occurring in patients undergoing bone marrow transplantation and total body irradiation. Both syndromes demonstrate the same pathological lesion: veno-occlusive disease. The main treatment for radiation hepatitis is diuretics, although soma advocate steroids for severe cases. (authors)

  7. 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

  8. Radiation exposure and radioprotection of physicians, technologists and nurses during their contact with patients who are or were subjected to studies with ionizing radiation

    OpenAIRE

    Charilaos Koutis; Athanasios Kotsalos; Eirini Kotsalou

    2013-01-01

    The applications of emission x- g- and b- rays in Medicine give solution to everyday diagnostic and therapeutic problems, but expose the Medical staff in radiation risk and its consequences. Aim: The purpose of this article was the review of literature relating to the risk of radiation exposure and radiation protection instructions for doctors, technologists and nurses during their contact with patients who have or had performed studies using ionizing radiation. Method and Material: The metho...

  9. Performance Improvement of Total Ionization Dose Radiation Sensor Devices Using Fluorine-Treated MOHOS

    Directory of Open Access Journals (Sweden)

    Wen-Ching Hsieh

    2016-03-01

    Full Text Available Fluorine-treated titanium nitride–silicon oxide–hafnium oxide–silicon oxide–silicon devices (hereafter F-MOHOS are candidates for total ionization dose (TID radiation sensor applications. The main subject of the study reportedherein is the performance improvement in terms of TID radiation-induced charge generation effect and charge-retention reliability characterization for F-MOHOS devices. In the case of F-MOHOS TID radiation sensors, the gamma radiation induces a significant decrease of threshold voltage VT and the radiation-induced charge density is nearly six times larger than that of standard metal–oxide–nitride–oxide–silicon MONOS devices. The decrease of VT for F-MOHOS after gamma irradiation has a strong correlation to the TID up to 5 Mrad gamma irradiation as well. The improvement of charge retention loss for F-MOHOS devices is nearly 15% better than that of metal–oxide–hafnium oxide–oxide–silicon MOHOS devices. The F-MOHOS device described in this study demonstrates better feasibility for non-volatile TID radiation sensing in the future.

  10. Effects of ionizing radiations on bacterial endotoxins: Comparison between gamma radiations and accelerated electrons

    Science.gov (United States)

    Guyomard, S.; Goury, V.; Darbord, J. C.

    Determinations of the effect of radiation sterilization processing on purified endotoxins, in aqueous solution or on dried support, are reported. These observations allow us to accept gamma radiations for sterilization of parenteral devices with an estimated probability of existence of non apyrogenic items, based upon a similar definition of the usual Sterility Assurance Level SAL = 10 -6).

  11. The influence of ionizing radiation, temperature, and light on eplerenone in the solid state.

    Science.gov (United States)

    Dettlaff, Katarzyna; Ogrodowczyk, Magdalena; Kycler, Witold; Dołhań, Agnieszka; Cwiertnia, Barbara; Garbacki, Piotr; Jelińska, Anna

    2014-01-01

    Eplerenone was subjected to the influence of ionizing radiation in the form of a high-energy electron beam (25-400 kGy), high temperature (90°C RH 0% and 60°C RH 76.4%), and light (6 mln lux h). An HPLC method was used to determine the content of eplerenone and to establish the impurity profile of all samples. As eplerenone was found to be a compound of great resistance to the above stress factors with the exception of high doses of ionizing radiation (≥ 200 kGy) when its degradation was above 1%, it is possible to sterilize eplerenone by radiation method with the standard dose of 25 kGy. Based on the analysis of impurities and degradation products, the mechanism of radiodegradation was demonstrated to differ from the mechanisms of photo- and thermodegradation. The observation that the DSC curves for the nondegraded and degraded samples of eplerenone were significantly different only under exposure to the electron beam confirmed the applicability of DSC for studies of radiolytic degradation of eplerenone.

  12. Radioprotective effect of atorvastatin against ionizing radiation-induced nephrotoxicity in mice.

    Science.gov (United States)

    Talebpour Amiri, Fereshteh; Hamzeh, Maedeh; Naeimi, Ramezan Ali; Ghasemi, Arash; Hosseinimehr, Seyed Jalal

    2018-02-01

    Kidneys are exposed to ionizing radiation during radiotherapy in patients with abdominal malignancy. The aim of this study is to investigate the protective effect of atorvastatin (ATV) against ionizing radiation-induced nephrotoxicity in mice. Sixty male BALB/c mice were randomly divided into six groups (10 mice per group); control, irradiation (IR), IR plus ATV (10, 20 and 50 mg/kg) and only ATV (50 mg/kg). ATV groups received ATV for seven days via oral gavage before exposure to IR. Animals were exposed to 2 Gy whole body of X-ray on day 8. After exposure to IR, biochemical, histological and immunohistological assays were performed. ATV significantly decreased the level of oxidative stress biomarkers in irradiated mice in comparison with IR alone. A significant reduction in the urea and creatinine levels was observed in ATV plus IR group compared to IR alone. Tubular degeneration, glomerular atrophy, interstitial expansion and fibrosis were observed in irradiated mice. Tubular degeneration and atrophy in the kidneys of IR plus ATV group were less than IR group. In addition, pre-treated animal with ATV significantly showed reduction in caspase-3 immunoreactivity. ATV has significant protective effect against radiation-induced nephrotoxicity in mice and is a promising medication for protection of patients during radiotherapy.

  13. Low-Dose Ionizing Radiation Exposure, Oxidative Stress and Epigenetic Programing of Health and Disease.

    Science.gov (United States)

    Tharmalingam, Sujeenthar; Sreetharan, Shayenthiran; Kulesza, Adomas V; Boreham, Douglas R; Tai, T C

    2017-10-01

    Ionizing radiation exposure from medical diagnostic imaging has greatly increased over the last few decades. Approximately 80% of patients who undergo medical imaging are exposed to low-dose ionizing radiation (LDIR). Although there is widespread consensus regarding the harmful effects of high doses of radiation, the biological effects of low-linear energy transfer (LET) LDIR is not well understood. LDIR is known to promote oxidative stress, however, these levels may not be large enough to result in genomic mutations. There is emerging evidence that oxidative stress causes heritable modifications via epigenetic mechanisms (DNA methylation, histone modification, noncoding RNA regulation). These epigenetic modifications result in permanent cellular transformations without altering the underlying DNA nucleotide sequence. This review summarizes the major concepts in the field of epigenetics with a focus on the effects of low-LET LDIR (stress on epigenetic gene modification. In this review, we show evidence that suggests that LDIR-induced oxidative stress provides a mechanistic link between LDIR and epigenetic gene regulation. We also discuss the potential implication of LDIR exposure during pregnancy where intrauterine fetal development is highly susceptible to oxidative stress-induced epigenetic programing.

  14. 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.

  15. Low-Dose, Ionizing Radiation and Age-Related Changes in Skeletal Microarchitecture

    Directory of Open Access Journals (Sweden)

    Joshua S. Alwood

    2012-01-01

    Full Text Available Osteoporosis can profoundly affect the aged as a consequence of progressive bone loss; high-dose ionizing radiation can cause similar changes, although less is known about lower doses (≤100 cGy. We hypothesized that exposure to relatively low doses of gamma radiation accelerates structural changes characteristic of skeletal aging. Mice (C57BL/6J-10 wk old, male were irradiated (total body; 0-sham, 1, 10 or 100 cGy 137Cs and tissues harvested on the day of irradiation, 1 or 4 months later. Microcomputed tomography was used to quantify microarchitecture of high turnover, cancellous bone. Irradiation at 100 cGy caused transient microarchitectural changes over one month that were only evident at longer times in controls (4 months. Ex vivo bone cell differentiation from the marrow was unaffected by gamma radiation. In conclusion, acute ionizing gamma irradiation at 100 cGy (but not at 1 cGy or 10 cGy exacerbated microarchitectural changes normally found during progressive, postpubertal aging prior to the onset of age-related osteoporosis.

  16. Genetic Background Modulates lncRNA-Coordinated Tissue Response to Low Dose Ionizing Radiation

    Directory of Open Access Journals (Sweden)

    Jonathan Tang

    2015-01-01

    Full Text Available Long noncoding RNAs (lncRNAs are emerging as key regulators of diverse cell functions and processes. However, the relevance of lncRNAs in the cell and tissue response to ionizing radiation has not yet been characterized. Here we used microarray profiling to determine lncRNA and mRNA expression in mammary glands of BALB/c and SPRET/EiJ mice after low-dose ionizing radiation (LDIR exposure. We found that unirradiated mammary tissues of these strains differed significantly in baseline expressions of 290 lncRNAs. LDIR exposure (10 cGy induced a significant change in the expression of many lncRNAs. The vast majority of lncRNAs identified to be differentially expressed after LDIR in either BALB/c or SPRET/EiJ had a significantly correlated expression pattern with at least one LDIR responsive mRNA. Functional analysis revealed that the response to LDIR in BALB/c mice is highly dynamic with enrichment for genes involved in tissue injury, inflammatory responses, and mammary gland development at 2, 4, and 8 weeks after LDIR, respectively. Our study demonstrates that genetic background strongly influences the expression of lncRNAs and their response to radiation and that lncRNAs may coordinate the tissue response to LDIR exposure via regulation of coding mRNAs.

  17. 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.

  18. 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.

  19. 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.

  20. The interaction of melanin with ionizing and UVC radiations: Characterization of thymine damage

    Energy Technology Data Exchange (ETDEWEB)

    Huselton, C.A.

    1988-01-01

    These studies were undertaken to determine whether melanin could protect DNA against the harmful effects of ionizing or UVC radiations. A simple, in vitro, model system was developed to evaluate eumelanin (Sigma melanin) as a radioprotector of solutions of 0.1 mM thymine or thymidine exposed to 570Gy of ionizing radiation. Sigma melanin was compared to several amino acids, other biomolecules or to other forms of melanin. To investigate the role of melanin as a passive screen of UVC radiation, melanotic (I{sub 3}), amelanotic (AMEL) cells (both derived from a Cloudman S91 melanoma) and non-melanotic (EMT6) cells were labelled with radioactive dTHd and exposed to 0, 1, 5 or 10KJ/m{sup 2} of UVC. The DNA was extracted; the bases hydrolyzed with concentrated HCl. Thymine bases were separated by reverse phase HPLC. No difference in dimer content was observed between I{sub 3} and AMEL cells, but EMT6 cells had nearly twice the amount of dimer. Overall thymine degradation was more pronounced in I{sub 3} cells than in the other two cell lines, due to the production of non-dimer thymine damage. This damage was identified as thymine glycol by HPLC and mass spectrometry. Melanin, upon exposure to UVC, appears to enhance thymine damage by producing oxidative damage.

  1. 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.

  2. CD47 Receptor Globally Regulates Metabolic Pathways That Control Resistance to Ionizing Radiation.

    Science.gov (United States)

    Miller, Thomas W; Soto-Pantoja, David R; Schwartz, Anthony L; Sipes, John M; DeGraff, William G; Ridnour, Lisa A; Wink, David A; Roberts, David D

    2015-10-09

    Modulating tissue responses to stress is an important therapeutic objective. Oxidative and genotoxic stresses caused by ionizing radiation are detrimental to healthy tissues but beneficial for treatment of cancer. CD47 is a signaling receptor for thrombospondin-1 and an attractive therapeutic target because blocking CD47 signaling protects normal tissues while sensitizing tumors to ionizing radiation. Here we utilized a metabolomic approach to define molecular mechanisms underlying this radioprotective activity. CD47-deficient cells and cd47-null mice exhibited global advantages in preserving metabolite levels after irradiation. Metabolic pathways required for controlling oxidative stress and mediating DNA repair were enhanced. Some cellular energetics pathways differed basally in CD47-deficient cells, and the global declines in the glycolytic and tricarboxylic acid cycle metabolites characteristic of normal cell and tissue responses to irradiation were prevented in the absence of CD47. Thus, CD47 mediates signaling from the extracellular matrix that coordinately regulates basal metabolism and cytoprotective responses to radiation injury. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  3. Optical and histological evaluation in human tendon tissue sterilized by ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Funari, Ana Paula; Antebi, Uri; Santos, Luiz Augusto; Vieira, Daniel Perez; Miranda, Jurandir Tomaz de; Alves, Nelson Mendes; Freitas, Anderson Zanardi de; Mathor, Monica Beatriz, E-mail: anapaulafunari@gmail.com, E-mail: mathor@ipen.br, E-mail: uri@usp.br, E-mail: luiz.santos@hc.fm.usp.br, E-mail: tomazdemiranda.j@gmail.com, E-mail: nelsonnininho@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Faculdade de Ciências Médicas da Santa Casa de São Paulo, SP (Brazil); Universidade de São Paulo (USP), SP (Brazil). Faculdade de Medicina; Universidade Federal de Santa Maria (UFSM), RS (Brazil)

    2017-11-01

    Sterilization by irradiation is a technique that is used by tissue banks aiming to eliminate contamination of human allografts, being a safe method, free of residue and used as final sterilization. After the tissue procurement, these undergo a series of processing stages and then are packaged and preserved by freezing. Despite aseptic care of the material those may be subjected to sterilization in the final packing by ionizing radiation, raising the security level of sterility of the tissue. The aim of this study was to evaluate the effects of application of ionizing radiation, produced by {sup 60}Co source in human tendons pre-processed (A-alcohol + antibiotic; B- H{sub 2}O{sub 2} + ultrasound) obtained through collaboration with tissue banks and preserved by freezing in -80° C, the radiation absorbed doses in processing were 12.5, 15 and 25 kGy, each one with their corresponding non-irradiated control, to examine possible structural or morphological alterations. The irradiated samples and their controls were analyzed by means of optical coherence tomography (OCT) and optical coherence tomography polarization sensitive (PS-OCT), and histological tests had been stained with hematoxylin-eosin (HE). According to the results the tissue processed with alcohol/antibiotic in conjunction with irradiation proved to be the most effective. (author)

  4. a New Model of the Chemistry of Ionizing Radiation in Solids

    Science.gov (United States)

    Shingledecker, Christopher N.; Herbst, Eric

    2017-06-01

    Cosmic rays are a form of high energy radiation found throughout the galaxy that can cause significant physio-chemical changes in solids, such as interstellar dust grain ice-mantles. These particles consist mostly of protons and can initiate a solid-state irradiation chemistry of significant astrochemical interest. In order to better understand the chemical effects of long-term exposure to ionizing radiation, we have written a new Monte Carlo model, CIRIS: the Chemistry of Ionizing Radiation in Solids, which is, to the best of our knowledge, the first successful program of its kind to follow the damage and subsequent chemistry of an irradiated material over time. In our code, two distinct regimes are considered. One is dominated by the atomic physics of track calculations in which both the irradiating proton and the subsequently generated secondary electrons are followed on a collision by collision basis. The other regime occurs after the ion-target collision, in which mobile species are free to randomly hop throughout the bulk of the ice and react via a diffusive mechanism. Here, we will present an initial test of our code in which we have successfully modeled previous experimental work. In these simulations, we are able to reproduce the measured abundances and predict the approximate ice thickness used in that study.

  5. Ionizing radiation-induced oxidative stress alters miRNA expression.

    Directory of Open Access Journals (Sweden)

    Nicole L Simone

    Full Text Available BACKGROUND: MicroRNAs (miRNAs are small, highly conserved, non-coding RNA that alter protein expression and regulate multiple intracellular processes, including those involved in the response to cellular stress. Alterations in miRNA expression may occur following exposure to several stress-inducing anticancer agents including ionizing radiation, etoposide, and hydrogen peroxide (H(2O(2. METHODOLOGY/PRINCIPAL FINDINGS: Normal human fibroblasts were exposed to radiation, H(2O(2, or etoposide at doses determined by clonogenic cell survival curves. Total RNA was extracted and miRNA expression was determined by microarray. Time course and radiation dose responses were determined using RT-PCR for individual miRNA species. Changes in miRNA expression were observed for 17 miRNA species following exposure to radiation, 23 after H(2O(2 treatment, and 45 after etoposide treatment. Substantial overlap between the miRNA expression changes between agents was observed suggesting a signature miRNA response to cell stress. Changes in the expression of selected miRNA species varied in response to radiation dose and time. Finally, production of reactive oxygen species (ROS increased with increasing doses of radiation and pre-treatment with the thiol antioxidant cysteine decreased both ROS production and the miRNA response to radiation. CONCLUSIONS: These results demonstrate a common miRNA expression signature in response to exogenous genotoxic agents including radiation, H(2O(2, and etoposide. Additionally, pre-treatment with cysteine prevented radiation-induced alterations in miRNA expression which suggests that miRNAs are responsive to oxidative stress. Taken together, these results imply that miRNAs play a role in cellular defense against exogenous stress and are involved in the generalized cellular response to genotoxic oxidative stress.

  6. Radiative lifetime measurements and oscillator strengths of astrophysical interest in HoIII

    OpenAIRE

    Zhang, Zhiguo; Somesfalean, Gabriel; Svanberg, Sune; Palmeri, P.; Quinet, P.; Biemont, E.

    2002-01-01

    Radiative lifetimes of three long-lived levels belonging to the 4f(10)5d configuration of Ho III have been measured, for the first time, using the time-resolved laser-induced fluorescence technique. A good agreement between the experimental lifetimes and theoretical results obtained within a multiconfigurational pseudo-relativistic Hartree-Fock (HFR) approach including core-polarization (CP) effects is observed provided an adequate scaling factor is applied to the <4f&VERBAR;r&VERB...

  7. 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.

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

    Directory of Open Access Journals (Sweden)

    Uri Antebi

    2016-04-01

    Full Text Available 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.

  9. 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

    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. 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. 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. 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.

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

    Science.gov (United States)

    Mathew, Sherin T; Bergström, Petra; Hammarsten, Ola

    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. Copyright © 2014 Elsevier Inc. All rights reserved.

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

    OpenAIRE

    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 ...

  12. 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)

  13. 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.

  14. Electron modes of plasma generated at tunnel ionization of atoms by a circularly polarized radiation

    Science.gov (United States)

    Vagin, K. Yu.; Uryupin, S. A.

    2017-10-01

    The collective modes of photoionized plasmas are studied using the model description of electron velocity distribution formed at tunnel ionization of atoms by circularly polarized radiation. The dispersion laws of transverse and approximately longitudinal high-frequency waves propagating at an arbitrary angle to the anisotropy axis of photoelectron distribution are obtained. The dispersion law of potential surface waves is derived. It is shown that the frequency of these waves may be greater than plasma frequency. The aperiodic instability of photoionized plasmas is described.

  15. Hydrogen-rich PBS protects cultured human cells from ionizing radiation-induced cellular damage

    Directory of Open Access Journals (Sweden)

    Qian Liren

    2010-01-01

    Full Text Available Hydroxyl radicals play an important role in ionizing radiation-induced cellular damage, while hydrogen can selectively reduce hydroxyl radicals in vitro. This study was designed to test the hypothesis that hydrogen-rich PBS may be an effective radioprotective agent in vitro. Compared to cells pretreated without hydrogen, we demonstrated that treating cells with hydrogen-rich PBS before irradiation could significantly inhibit IR-induced apoptosis, increase viability of human intestinal crypt cells, significantly increase endogenous antioxidant, and decrease malondialdehyde and 8-hydroxydeoxyguanosine concentrations of human lymphocyte AHH-1 cells. It is concluded that hydrogen has a potential as an effective and safe radioprotective agent.

  16. 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.

  17. In Vivo Imaging of Microglia Turnover in the Mouse Retina After Ionizing Radiation and Dexamethasone Treatment

    DEFF Research Database (Denmark)

    Alt, C.; Runnels, J. M.; Mortensen, L. J.

    2014-01-01

    to the microglia loss, resulting in a transient depletion of the total immune cell number in the retina. With dexamethasone treatment, both the loss of the resident microglia and the infiltration of BMDCs were suppressed by at least 50%. CONCLUSIONS. Anti-inflammatory treatment with the corticosteroidal agent...... and bone marrow transplantation from universal DsRed donor mice. Mice were treated with the corticosteroid dexamethasone; a control group received no dexamethasone treatment. The populations of resident microglia (GFP+) and BMDCs (DsRed+) were quantified by serial in vivo imaging for 10 weeks after...... dexamethasone preserves resident microglia and minimizes recruitment of BMDCs after ionizing radiation exposure and BMT....

  18. Modeling of radiation-induced charge trapping in MOS devices under ionizing irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Petukhov, M. A., E-mail: m.a.petukhov@gmail.com; Ryazanov, A. I. [National Research Center Kurchatov Institute (Russian Federation)

    2016-12-15

    The numerical model of the radiation-induced charge trapping process in the oxide layer of a MOS device under ionizing irradiation is developed; the model includes carrier transport, hole capture by traps in different states, recombination of free electrons and trapped holes, kinetics of hydrogen ions which can be accumulated in the material during transistor manufacture, and accumulation and charging of interface states. Modeling of n-channel MOSFET behavior under 1 MeV photon irradiation is performed. The obtained dose dependences of the threshold voltage shift and its contributions from trapped holes and interface states are in good agreement with experimental data.

  19. 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.

  20. Medical radiation workers’ knowledge, attitude, and practice to protect themselves against ionizing radiation in Tehran Province, Iran

    Science.gov (United States)

    Alavi, Seyedeh Shohreh; Dabbagh, Sima Taghizadeh; Abbasi, Mahya; Mehrdad, Ramin

    2017-01-01

    BACKGROUND: Medical radiation workers are potentially at a risk of unwanted ionizing radiation exposures. This study assessed the radiation protection knowledge, attitude, and practice (RP-KAP) of health-care workers who are occupationally exposed to radiation regarding protecting themselves from radiation. MATERIALS AND METHODS: This study was cross-sectional in design and was carried out in 16 hospitals affiliated to the Tehran University of Medical Sciences between May and September 2014. Total health-care workers who were occupationally exposed to radiation comprising 670 individuals were included in the study based on census sampling method. In total, 413 individuals consented to complete an anonymous 32-item questionnaire comprising single best choice questions with a numerical value assigned to each correct answer. Each set of RP-KAP questions was scored and categorized as poor, medium, and good. The effect of independent variables for prediction of RP-KAP was explored using linear regression analyses. RESULTS: A significant number of participants had poor RP-knowledge (78.9%), RP-attitude (70.7%), and RP-practice (32.4%). Based on linear regression analyses, it was found that field of study (β = 0.1, P = 0.001), marital status (β = −0.14, P = 0.01), and level of education (β = 0.2, P knowledge. In-service RP-training (β = 0.1, P = 0.04) was associated with an increased RP-attitude. Being a woman (β = 0.2, P practice. CONCLUSION: In-service training with appropriate qualified and up-to-date materials based on radiation workers’ educational needs and approved protocols and guidelines is recommended. PMID:28616425

  1. Medical radiation workers' knowledge, attitude, and practice to protect themselves against ionizing radiation in Tehran Province, Iran.

    Science.gov (United States)

    Alavi, Seyedeh Shohreh; Dabbagh, Sima Taghizadeh; Abbasi, Mahya; Mehrdad, Ramin

    2017-01-01

    Medical radiation workers are potentially at a risk of unwanted ionizing radiation exposures. This study assessed the radiation protection knowledge, attitude, and practice (RP-KAP) of health-care workers who are occupationally exposed to radiation regarding protecting themselves from radiation. This study was cross-sectional in design and was carried out in 16 hospitals affiliated to the Tehran University of Medical Sciences between May and September 2014. Total health-care workers who were occupationally exposed to radiation comprising 670 individuals were included in the study based on census sampling method. In total, 413 individuals consented to complete an anonymous 32-item questionnaire comprising single best choice questions with a numerical value assigned to each correct answer. Each set of RP-KAP questions was scored and categorized as poor, medium, and good. The effect of independent variables for prediction of RP-KAP was explored using linear regression analyses. A significant number of participants had poor RP-knowledge (78.9%), RP-attitude (70.7%), and RP-practice (32.4%). Based on linear regression analyses, it was found that field of study (β = 0.1, P = 0.001), marital status (β = -0.14, P = 0.01), and level of education (β = 0.2, P knowledge. In-service RP-training (β = 0.1, P = 0.04) was associated with an increased RP-attitude. Being a woman (β = 0.2, P practice. In-service training with appropriate qualified and up-to-date materials based on radiation workers' educational needs and approved protocols and guidelines is recommended.

  2. 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

  3. 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.

  4. Mesenchymal Stem Cells Retain Their Defining Stem Cell Characteristics After Exposure to Ionizing Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Nicolay, Nils H., E-mail: n.nicolay@dkfz.de [Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg (Germany); Department of Molecular and Radiation Oncology, German Cancer Research Center, Heidelberg (Germany); Sommer, Eva; Lopez, Ramon; Wirkner, Ute [Department of Molecular and Radiation Oncology, German Cancer Research Center, Heidelberg (Germany); Trinh, Thuy [Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg (Germany); Department of Molecular and Radiation Oncology, German Cancer Research Center, Heidelberg (Germany); Sisombath, Sonevisay [Department of Molecular and Radiation Oncology, German Cancer Research Center, Heidelberg (Germany); Debus, Jürgen [Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg (Germany); Ho, Anthony D.; Saffrich, Rainer [Department of Hematology and Oncology, Heidelberg University Hospital, Heidelberg (Germany); Huber, Peter E. [Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg (Germany); Department of Molecular and Radiation Oncology, German Cancer Research Center, Heidelberg (Germany)

    2013-12-01

    Purpose: Mesenchymal stem cells (MSCs) have the ability to migrate to lesion sites and undergo differentiation into functional tissues. Although this function may be important for tissue regeneration after radiation therapy, the influence of ionizing radiation (IR) on cellular survival and the functional aspects of differentiation and stem cell characteristics of MSCs have remained largely unknown. Methods and Materials: Radiation sensitivity of human primary MSCs from healthy volunteers and primary human fibroblast cells was examined, and cellular morphology, cell cycle effects, apoptosis, and differentiation potential after exposure to IR were assessed. Stem cell gene expression patterns after exposure to IR were studied using gene arrays. Results: MSCs were not more radiosensitive than human primary fibroblasts, whereas there were considerable differences regarding radiation sensitivity within individual MSCs. Cellular morphology, cytoskeletal architecture, and cell motility were not markedly altered by IR. Even after high radiation doses up to 10 Gy, MSCs maintained their differentiation potential. Compared to primary fibroblast cells, MSCs did not show an increase in irradiation-induced apoptosis. Gene expression analyses revealed an upregulation of various genes involved in DNA damage response and DNA repair, but expression of established MSC surface markers appeared only marginally influenced by IR. Conclusions: These data suggest that human MSCs are not more radiosensitive than differentiated primary fibroblasts. In addition, upon photon irradiation, MSCs were able to retain their defining stem cell characteristics both on a functional level and regarding stem cell marker expression.

  5. 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.

  6. 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.

  7. Non-targeted and delayed effects of exposure to ionizing radiation: I. Radiation-induced genomic instability and bystander effects in vitro

    Science.gov (United States)

    Morgan, William F.

    2003-01-01

    A long-standing dogma in the radiation sciences is that energy from radiation must be deposited in the cell nucleus to elicit a biological effect. A number of non-targeted, delayed effects of ionizing radiation have been described that challenge this dogma and pose new challenges to evaluating potential hazards associated with radiation exposure. These effects include induced genomic instability and non-targeted bystander effects. The in vitro evidence for non-targeted effects in radiation biology will be reviewed, but the question as to how one extrapolates from these in vitro observations to the risk of radiation-induced adverse health effects such as cancer remains open.

  8. 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.

  9. Impact of ionizing radiation on physicochemical and biological properties of an amphiphilic macromolecule.

    Science.gov (United States)

    Gu, Li; Zablocki, Kyle; Lavelle, Linda; Bodnar, Stanko; Halperin, Frederick; Harper, Ike; Moghe, Prabhas V; Uhrich, Kathryn E

    2012-09-01

    An amphiphilic macromolecule (AM) was exposed to ionizing radiation (both electron beam and gamma) at doses of 25 kGy and 50 kGy to study the impact of these sterilization methods on the physicochemical properties and bioactivity of the AM. Proton nuclear magnetic resonance and gel permeation chromatography were used to determine the chemical structure and molecular weight, respectively. Size and zeta potential of the micelles formed from AMs in aqueous media were evaluated by dynamic light scattering. Bioactivity of irradiated AMs was evaluated by measuring inhibition of oxidized low-density lipoprotein uptake in macrophages. From these studies, no significant changes in the physicochemical properties or bioactivity were observed after the irradiation, demonstrating that the AMs can withstand typical radiation doses used to sterilize materials.

  10. 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.

  11. Hyperion net: A distributed measurement system for monitoring background ionizing radiation

    Directory of Open Access Journals (Sweden)

    Šaponjić Đorđe P.

    2003-01-01

    Full Text Available The distributed measurement system - HYPERION NET, based on the concept of FieldBus technology, has been developed, implemented, and tested as a pilot project, the first WEB enabled on-line networked ionizing radiation monitoring and measurement system. The Net has layered the structure, tree topology, and is based on the Internet infrastructure and TCP/IP communication protocol. The Net' s core element is an intelligent GM transmitter, based on GM tube, used for measuring the absorbed dose in air in the range of 0.087 to 720 μGy/h. The transmitter makes use of an advanced count rate measurement algorithm capable of suppressing the statistical fluctuations of the measured quantity, which significantly improves its measurement performance making it suitable for environmental radiation measurements.

  12. Childhood exposure to ionizing radiation from computed tomography imaging in Nova Scotia.

    Science.gov (United States)

    Inman, Mark; Otley, Anthony; Dummer, Trevor; Cui, Yunsong; Schmidt, Matthias H; Parker, Louise

    2015-10-01

    Examining radiation dose in the paediatric population is particularly important due to the vulnerability of paediatric patients (increased radiosensitive tissues and postexposure life-years) and risk for future radiogenic malignancy. To evaluate trends in paediatric computed tomography (CT) use and ionizing radiation exposure using population-based data from Nova Scotia. A retrospective, population-based cohort study of CT use in patients Nova Scotia. CT examination data were retrieved from a provincial imaging repository. Trends in CT use were described, and both annual and cumulative effective dose exposures were calculated. In total, 29,452 CT events, involving up to 22,867 individuals were retrieved. Overall annual paediatric CT examination rates remained static (range 17.4 to 18.8 per 1000 per year). However, use in children 50% (P50 mSv), and rates in individuals >15 years of age steadily increased, suggesting further exposure reduction efforts are necessary.

  13. Ionizing radiation enhances IL-6 and IL-8 production by human endothelial cells

    Directory of Open Access Journals (Sweden)

    A. Van Der Meeren

    1997-01-01

    Full Text Available Irradiation exposure is known to induce an inflammatory reaction. Endothelial cells play a crucial role both in the inflammatory process and in radiation damage. Therefore, supernatants and cell lysates of 60Co-irradiated human umbilical vein endothelial cells (HUVEC have been assessed for the presence of pro-inflammatory cytokines. After gamma irradiation, interleukin (IL-1α, IL-1β and tumor necrosis factor (TNF-α remained undetectable in both cell supernatants and cell lysates. However, a dose-dependent increase in the production of IL-6 and IL-8 has been demonstrated up to 6 days after exposure. These data indicate that the pro-inflammatory cytokines IL-6 and IL-8 may be involved in the inflammatory response of vascular endothelium induced by exposure to ionizing radiation.

  14. 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)

  15. 5-Aminoimidazole-4-Carboxamide Riboside Enhances Effect of Ionizing Radiation in PC3 Prostate Cancer Cells

    Energy Technology Data Exchange (ETDEWEB)

    Isebaert, Sofie F., E-mail: sofie.isebaert@med.kuleuven.be [Department of Radiation Oncology, University Hospitals Leuven Campus Gasthuisberg, Leuven (Belgium); Swinnen, Johannes V. [Department of Experimental Medicine and Endocrinology, Katholieke Universiteit Leuven, Leuven (Belgium); McBride, William H. [Department of Radiation Oncology, University of California, Los Angeles, School of Medicine, Los Angeles, CA (United States); Begg, Adrian C. [Division of Experimental Therapy, Netherlands Cancer Institute, Amsterdam (Netherlands); Haustermans, Karin M. [Department of Radiation Oncology, University Hospitals Leuven Campus Gasthuisberg, Leuven (Belgium)

    2011-12-01

    Purpose: The nucleoside 5-aminoimidazole-4-carboxamide riboside (AICAR) is a low-energy mimetic and adenosine monophosphate (AMP)-activated protein kinase (AMPK) agonist that can affect the phenotype of malignant cells by diminishing their anabolism. It does this by being converted to 5-aminoimidazole-4-carboxamide ribotide (ZMP), an AMP analog. We combined this promising antineoplastic agent with ionizing radiation in an attempt to increase its efficacy. Methods and Materials: The effect of AICAR on cell proliferation, cell viability, apoptosis, reactive oxygen species production, radiosensitivity, and AMPK activation was determined in the human prostate cancer cell line PC3. To elucidate the radiosensitizing mechanism, clonogenic survival assays in the presence of a drug agonist or antagonist or with small interfering RNA targeting AMPK were done, as well as measurements of ZMP production and double strand break repair. Moreover, immunoblot analysis of the radiation response signaling pathways after AICAR treatment was performed. Results: The incubation of human PC3 prostate cancer cells with AICAR-activated AMPK inhibited cell proliferation, decreased viability, increased apoptosis, and generated reactive oxygen species in a dose- and time-dependent manner. None of these endpoints gave more than additive effects when radiation was added. Radiosensitization was observed but only after 72 hours of treatment with 250 {mu}M AICAR, suggesting that it was independent of AMPK activation. This finding was confirmed by small interfering RNA knockdown of AMPK. The mechanism of radiosensitization was associated with imbalanced deoxynucleotide pools owing to ZMP accumulation after AICAR administration that interfered with DNA repair. Conclusions: Our findings on the favorable interaction between low doses of AICAR and ionizing radiation in PC3 cells could open new perspectives for the clinical use of this or similar compounds. However, additional research is still required

  16. Gossypetin ameliorates ionizing radiation-induced oxidative stress in mice liver--a molecular approach.

    Science.gov (United States)

    Khan, Amitava; Manna, Krishnendu; Das, Dipesh Kr; Kesh, Swaraj Bandhu; Sinha, Mahuya; Das, Ujjal; Biswas, Sushobhan; Sengupta, Aaveri; Sikder, Kunal; Datta, Sanjukta; Ghosh, Mahua; Chakrabarty, Anindita; Banerji, Asoke; Dey, Sanjit

    2015-10-01

    Radioprotective action of gossypetin (GTIN) against gamma (γ)-radiation-induced oxidative stress in liver was explored in the present article. Our main aim was to evaluate the protective efficacy of GTIN against radiation-induced alteration of liver in murine system. To evaluate the effect of GTIN, it was orally administered to mice at a dose of 30 mg/kg body weight for three consecutive days prior to γ-radiation at a dose of 5 Gy. Radioprotective efficacy of GTIN were evaluated at physiological, cellular, and molecular level using biochemical analysis, comet assay, flow cytometry, histopathology, immunofluorescence, and immunoblotting techniques. Ionizing radiation was responsible for augmentation of hepatic oxidative stress in terms of lipid peroxidation and depletion of endogenous antioxidant enzymes. Immunoblotting and immunofluorescence studies showed that irradiation enhanced the nuclear translocation of nuclear factor kappa B (NF-κB) level, which leads to hepatic inflammation. To investigate further, we found that radiation induced the activation of stress-activated protein kinase/c-Jun NH2-terminal kinase (SAPK/JNK)-mediated apoptotic pathway and deactivation of the NF-E2-related factor 2 (Nrf2)-mediated redox signaling pathway, whereas GTIN pretreatment ameliorated these radiation-mediated effects. This is the novel report where GTIN rationally validated the molecular mechanism in terms of the modulation of cellular signaling system' instead of ' This is the novel report where GTIN is rationally validated in molecular terms to establish it as promising radioprotective agents. This might be fruitful especially for nuclear workers and defense personnel assuming the possibility of radiation exposure.

  17. 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

  18. 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.

  19. Modeling the radiation ionization energy and energy resolution of trigonal and amorphous selenium from first principles.

    Science.gov (United States)

    Darbandi, A; Devoie, É; Di Matteo, O; Rubel, O

    2012-11-14

    Advances in the development of amorphous selenium-based direct conversion photoconductors for high-energy radiation critically depend on the improvement of its sensitivity to ionizing radiation, which is directly related to the pair production energy. Traditionally, theories for the pair production energy have been based on the parabolic band approximation and do not provide a satisfactory agreement with experimental results for amorphous selenium. Here we present a calculation of the pair creation energy in trigonal and amorphous selenium based on its electronic structure. In indirect semiconductors, such as trigonal selenium, the ionization threshold energy can be as low as the energy gap, resulting in a lower pair creation energy, which is a favorable factor for sensitivity. Also, the statistics of photogenerated charge carriers is studied in order to evaluate the theoretical value of the Fano factor and its dependence on recombination processes. We show that recombination can significantly compromise the detector's energy resolution as a result of an increase in the Fano factor.

  20. Effect of ionizing radiation on the taste function of patients submitted to head and neck radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Amaro Ilidio Vespasiano [Universidade Estadual de Campinas (UNICAMP), SP (Brazil); Galante, Celio [Santa Casa de Misericordia de Belo Horizonte, MG (Brazil). Div. de Radioterapia; Manzi, Flavio Ricardo, E-mail: manzi@pucminas.b [Pontificia Universidade Catolica de Minas Gerais (PUC-MG), Belo Horizonte, MG (Brazil)

    2011-09-15

    Objective: to evaluate the effects of ionizing radiation on the taste function in patients submitted to radiotherapy in the head and neck region. Materials and methods: twenty patients diagnosed with head and neck tumors and undergoing treatment in the Division of Radiotherapy at Santa Casa de Misericordia de Belo Horizonte, MG, Brazil, were selected. For their taste function testing, four solutions were manipulated with salt (NaCl), sugar (sucrose), citric acid (for acidity), and urea (for bitterness), at three different (low, medium and high) concentrations. Weekly tests were performed during the first three weeks of radiotherapy, with random administration of the solutions (three drops each) respecting the order of their concentration levels (low, medium and high). After the application of each solution, the patient reported which flavor he/she tasted. Results: a statistically significant difference was observed in the loss of taste function as the results in the 1st and 4th weeks of treatment were compared, with salty solution at the three concentration levels, with the sweet solution at low and medium concentrations, and with the sour and bitter solutions, only at low concentration. Conclusion: ionizing radiation alters the taste function of patients submitted to head and neck radiotherapy. (author)

  1. Effects of ionizing radiation on free amino acid content of chick embryo blood plasma. [. gamma. radiation

    Energy Technology Data Exchange (ETDEWEB)

    Todorov, B.; Dryanovski, P.; Simeonovska, M.

    1979-06-01

    Using thin-layer chromatography on cellulose film, it was demonstrated that there is a decrease in blood plasma free amino acids after exposing chick embryos to radiation (1000 rad). Only lysine and histidine content decreases on the 1st day. On the 2d, 3d, and 10th days, there is a decrease in lysine, histidine, arginine, glycine, glutamine, serine, aspartic and glutamic acids, threonine, and alanine. There was no change in amounts of leucine, isoleucine, phenylalanine, methionine, valine, and tyrosine throughout the observation period. It was demonstrated that there is a change in rate of migration of nonessential amino acids from egg albumin to embryo blood after exposure to radiation.

  2. 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.

  3. 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

  4. 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.

  5. The influence of ionizing radiation on itraconazole in the solid state.

    Science.gov (United States)

    Dettlaff, Katarzyna; Talik, Przemysław; Spólnik, Grzegorz; Danikiewicz, Witold; Ogrodowczyk, Magdalena

    2015-02-01

    The aim of this study was to investigate the ionizing radiation effects, in the form of an electron beam, on itraconazole (ITR) in the solid phase. It was found that the ITR, under the influence of a standard 25 kGy dose of radiation used for the sterilization of drug substances, decomposed at 0.4%. Moreover, a gentle change of colour and a decrease in melting point does not exceed pharmacopoeial standards causing that ITR can be sterilized by radiation method. The use of high 400 kGy radiation doses resulted in a 6.5% decomposition of the ITR and eight radiodegradation products were found. However, with the exception of differential scanning calorimetry (DSC), the X-ray diffraction, Fourier transform infrared spectroscopy (FT-IR) and ultraviolet-visible (UV-vis) methods showed no changes in the form and the morphology of the crystals. The structures of all those compounds were investigated. It was confirmed that the ITR decomposition takes place by dehalogenation (one of Cl atom elimination), the oxidation in isobutyl residue (beside the triazole ring) and C-O bond rupture.

  6. 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.

  7. 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.

  8. Long-term correlation of the electrocorticogram as a bioindicator of brain exposure to ionizing radiation.

    Science.gov (United States)

    Aguiar, L A A; Silva, I M S; Fernandes, T S; Nogueira, R A

    2015-10-01

    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.

  9. 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.

  10. Ionic Fragmentation of Methyl Methacrylate Induced by Synchrotron Radiation and Multiphoton Ionization

    Directory of Open Access Journals (Sweden)

    Quintella Cristina M.

    1998-01-01

    Full Text Available Ionic fragmentation of methylmethacrylate has been observed using synchrotron radiation and laser excitation. A recently developed time-of-flight mass spectrometer was used for the ionic identification. In the case of synchrotron radiation, both low energy (12.1 eV and high energy (287.9 eV photons were used. Although a definite increase in fragmentation was observed while moving from 12.1 to 287.9 eV, the fragmentation pattern remained basically the same in both cases. The parent peak stays clearly visible and intense fragments, associated with m/q = 15, 39, 41 and 69 dominate both synchrotron radiation-induced spectra. Multiphoton ionization causes much extensive fragmentation, the parent ion could not be observed, and C+ ion becomes the most intense peak in the spectrum. Ions at m/q = 15, 39, 41 and 69 are observed using laser and synchrotron radiation, which demonstrates their high stability. Doubly or multiply-charged ions have not been observed.

  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. 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)

  13. Amifostine, a radioprotectant agent, protects rat brain tissue lipids against ionizing radiation induced damage: An FTIR microspectroscopic imaging study

    Energy Technology Data Exchange (ETDEWEB)

    Cakmak G.; Miller L.; Zorlu, F.; Severcan, F.

    2012-03-03

    Amifostine is the only approved radioprotective agent by FDA for reducing the damaging effects of radiation on healthy tissues. In this study, the protective effect of amifostine against the damaging effects of ionizing radiation on the white matter (WM) and grey matter (GM) regions of the rat brain were investigated at molecular level. Sprague-Dawley rats, which were administered amifostine or not, were whole-body irradiated at a single dose of 800 cGy, decapitated after 24 h and the brain tissues of these rats were analyzed using Fourier transform infrared microspectroscopy (FTIRM). The results revealed that the total lipid content and CH{sub 2} groups of lipids decreased significantly and the carbonyl esters, olefinic=CH and CH{sub 3} groups of lipids increased significantly in the WM and GM after exposure to ionizing radiation, which could be interpreted as a result of lipid peroxidation. These changes were more prominent in the WM of the brain. The administration of amifostine before ionizing radiation inhibited the radiation-induced lipid peroxidation in the brain. In addition, this study indicated that FTIRM provides a novel approach for monitoring ionizing radiation induced-lipid peroxidation and obtaining different molecular ratio images can be used as biomarkers to detect lipid peroxidation in biological systems.

  14. Amifostine, a radioprotectant agent, protects rat brain tissue lipids against ionizing radiation induced damage: an FTIR microspectroscopic imaging study.

    Science.gov (United States)

    Cakmak, Gulgun; Miller, Lisa M; Zorlu, Faruk; Severcan, Feride

    2012-04-15

    Amifostine is the only approved radioprotective agent by FDA for reducing the damaging effects of radiation on healthy tissues. In this study, the protective effect of amifostine against the damaging effects of ionizing radiation on the white matter (WM) and grey matter (GM) regions of the rat brain were investigated at molecular level. Sprague-Dawley rats, which were administered amifostine or not, were whole-body irradiated at a single dose of 800 cGy, decapitated after 24 h and the brain tissues of these rats were analyzed using Fourier transform infrared microspectroscopy (FTIRM). The results revealed that the total lipid content and CH(2) groups of lipids decreased significantly and the carbonyl esters, olefinic=CH and CH(3) groups of lipids increased significantly in the WM and GM after exposure to ionizing radiation, which could be interpreted as a result of lipid peroxidation. These changes were more prominent in the WM of the brain. The administration of amifostine before ionizing radiation inhibited the radiation-induced lipid peroxidation in the brain. In addition, this study indicated that FTIRM provides a novel approach for monitoring ionizing radiation induced-lipid peroxidation and obtaining different molecular ratio images can be used as biomarkers to detect lipid peroxidation in biological systems. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. Ionizing radiation and risk of chronic lymphocytic leukemia in the 15-country study of nuclear industry workers

    DEFF Research Database (Denmark)

    Vrijheid, Martine; Cardis, Elisabeth; Ashmore, Patrick

    2008-01-01

    In contrast to other types of leukemia, chronic lymphocytic leukemia (CLL) has long been regarded as non-radiogenic, i.e. not caused by ionizing radiation. However, the justification for this view has been challenged. We therefore report on the relationship between CLL mortality and external...... ionizing radiation dose within the 15-country nuclear workers cohort study. The analyses included, in seven countries with CLL deaths, a total of 295,963 workers with more than 4.5 million person-years of follow-up and an average cumulative bone marrow dose of 15 mSv; there were 65 CLL deaths....... In conclusion, the largest nuclear workers cohort study to date finds little evidence for an association between low doses of external ionizing radiation and CLL mortality. This study had little power due to low doses, short follow-up periods, and uncertainties in CLL ascertainment from death certificates...

  16. Quantitative modeling of responses to chronic ionizing radiation exposure using targeted and non-targeted effects.

    Directory of Open Access Journals (Sweden)

    Igor Shuryak

    Full Text Available The biological effects of chronic ionizing radiation exposure can be difficult to study, but important to understand in order to protect the health of occupationally-exposed persons and victims of radiological accidents or malicious events. They include targeted effects (TE caused by ionizations within/close to nuclear DNA, and non-targeted effects (NTE caused by damage to other cell structures and/or activation of stress-signaling pathways in distant cells. Data on radiation damage in animal populations exposed over multiple generations to wide ranges of dose rates after the Chernobyl nuclear-power-plant accident are very useful for enhancing our understanding of these processes. We used a mechanistically-motivated mathematical model which includes TE and NTE to analyze a large published data set on chromosomal aberrations in pond snail (Lymnaea stagnalis embryos collected over 16 years from water bodies contaminated by Chernobyl fallout, and from control locations. The fraction of embryo cells with aberrations increased dramatically (>10-fold and non-linearly over a dose rate range of 0.03-420 μGy/h (0.00026-3.7 Gy/year. NTE were very important for describing the non-linearity of this radiation response: the TE-only model (without NTE performed dramatically worse than the TE+NTE model. NTE were predicted to reach ½ of maximal intensity at 2.5 μGy/h (0.022 Gy/year and to contribute >90% to the radiation response slope at dose rates <11 μGy/h (0.1 Gy/year. Internally-incorporated 90Sr was possibly more effective per unit dose than other radionuclides. The radiation response shape for chromosomal aberrations in snail embryos was consistent with data for a different endpoint: the fraction of young amoebocytes in adult snail haemolymph. Therefore, radiation may affect different snail life stages by similar mechanisms. The importance of NTE in our model-based analysis suggests that the search for modulators of NTE-related signaling pathways

  17. 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.

  18. Kidney cancer mortality and ionizing radiation among French and German uranium miners

    Energy Technology Data Exchange (ETDEWEB)

    Drubay, Damien; Ancelet, Sophie; Laurier, Dominique; Rage, Estelle [Institut de Radioprotection et de Surete Nucleaire (IRSN), Laboratory of Epidemiology, Fontenay-aux-Roses cedex (France); Acker, Alain [AREVA NC, Paris (France); Kreuzer, Michaela [Federal Office for Radiation Protection and Health, Department of Radiation Protection and Health, Neuherberg (Germany)

    2014-08-15

    The investigation of potential adverse health effects of occupational exposures to ionizing radiation, on uranium miners, is an important area of research. Radon is a well-known carcinogen for lung, but the link between radiation exposure and other diseases remains controversial, particularly for kidney cancer. The aims of this study were therefore to perform external kidney cancer mortality analyses and to assess the relationship between occupational radiation exposure and kidney cancer mortality, using competing risks methodology, from two uranium miners cohorts. The French (n = 3,377) and German (n = 58,986) cohorts of uranium miners included 11 and 174 deaths from kidney cancer. For each cohort, the excess of kidney cancer mortality has been assessed by standardized mortality ratio (SMR) corrected for the probability of known causes of death. The associations between cumulative occupational radiation exposures (radon, external gamma radiation and long-lived radionuclides) or kidney equivalent doses and both the cause-specific hazard and the probability of occurrence of kidney cancer death have been estimated with Cox and Fine and Gray models adjusted to date of birth and considering the attained age as the timescale. No significant excess of kidney cancer mortality has been observed neither in the French cohort (SMR = 1.49, 95 % confidence interval [0.73; 2.67]) nor in the German cohort (SMR = 0.91 [0.77; 1.06]). Moreover, no significant association between kidney cancer mortality and any type of occupational radiation exposure or kidney equivalent dose has been observed. Future analyses based on further follow-up updates and/or large pooled cohorts should allow us to confirm or not the absence of association. (orig.)

  19. Low-Temperature Ionizing Radiation Resistance of Deinococcus radiodurans and Antarctic Dry Valley Bacteria

    Science.gov (United States)

    Dartnell, Lewis R.; Hunter, Stephanie J.; Lovell, Keith V.; Coates, Andrew J.; Ward, John M.

    2010-09-01

    The high flux of cosmic rays onto the unshielded surface of Mars poses a significant hazard to the survival of martian microbial life. Here, we determined the survival responses of several bacterial strains to ionizing radiation exposure while frozen at a low temperature characteristic of the martian near-subsurface. Novel psychrotolerant bacterial strains were isolated from the Antarctic Dry Valleys, an environmental analogue of the martian surface, and identified by 16S rRNA gene phylogeny as representatives of Brevundimonas, Rhodococcus, and Pseudomonas genera. These isolates, in addition to the known radioresistant extremophile Deinococcus radiodurans, were exposed to gamma rays while frozen on dry ice (-79°C). We found D. radiodurans to exhibit far greater radiation resistance when irradiated at -79°C than was observed in similar studies performed at higher temperatures. This greater radiation resistance has important implications for the estimation of potential survival times of microorganisms near the martian surface. Furthermore, the most radiation resistant of these Dry Valley isolates, Brevundimonas sp. MV.7, was found to show 99% 16S rRNA gene similarity to contaminant bacteria discovered in clean rooms at both Kennedy and Johnson Space Centers and so is of prime concern to efforts in the planetary protection of Mars from our lander probes. Results from this experimental irradiation, combined with previous radiation modeling, indicate that Brevundimonas sp. MV.7 emplaced only 30 cm deep in martian dust could survive the cosmic radiation for up to 100,000 years before suffering 106 population reduction.

  20. Low-temperature ionizing radiation resistance of Deinococcus radiodurans and Antarctic Dry Valley bacteria.

    Science.gov (United States)

    Dartnell, Lewis R; Hunter, Stephanie J; Lovell, Keith V; Coates, Andrew J; Ward, John M

    2010-09-01

    The high flux of cosmic rays onto the unshielded surface of Mars poses a significant hazard to the survival of martian microbial life. Here, we determined the survival responses of several bacterial strains to ionizing radiation exposure while frozen at a low temperature characteristic of the martian near-subsurface. Novel psychrotolerant bacterial strains were isolated from the Antarctic Dry Valleys, an environmental analogue of the martian surface, and identified by 16S rRNA gene phylogeny as representatives of Brevundimonas, Rhodococcus, and Pseudomonas genera. These isolates, in addition to the known radioresistant extremophile Deinococcus radiodurans, were exposed to gamma rays while frozen on dry ice (-79°C). We found D. radiodurans to exhibit far greater radiation resistance when irradiated at -79°C than was observed in similar studies performed at higher temperatures. This greater radiation resistance has important implications for the estimation of potential survival times of microorganisms near the martian surface. Furthermore, the most radiation resistant of these Dry Valley isolates, Brevundimonas sp. MV.7, was found to show 99% 16S rRNA gene similarity to contaminant bacteria discovered in clean rooms at both Kennedy and Johnson Space Centers and so is of prime concern to efforts in the planetary protection of Mars from our lander probes. Results from this experimental irradiation, combined with previous radiation modeling, indicate that Brevundimonas sp. MV.7 emplaced only 30 cm deep in martian dust could survive the cosmic radiation for up to 100,000 years before suffering 10⁶ population reduction.

  1. 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.

  2. FT-IR spectroscopy assessment of aesthetic dental materials irradiated with low-dose therapeutic ionizing radiation

    Science.gov (United States)

    Cruz, A. D.; Almeida, S. M.; Rastelli, A. N. S.; Bagnato, V. S.; Byscolo, F. N.

    2009-03-01

    The aim of the present study was to evaluate the effects of low-dose therapeutic ionizing radiation on different aesthetic dental materials. Forty five specimens ( n = 45) of three different aesthetic restorative materials were prepared and randomly divided into five groups: G1 (control group); G2, G3, G4, G5 experimental groups irradiated respectively with 0.25, 0.50, 0.75, and 1.00 Gy of gamma radiation by the 60Co teletherapy machine. Chemical analyses were performed using a FT-IR Nicolet 520 spectrophotometer with reflectance diffuse technique. Even a minimal exposition at ionizing radiation in therapeutic doses can provide chemical changes on light-cured composite resins. The three studied restorative materials showed changes after exposure at gamma radiation, however the increase of the radiation dose did not contribute to an increase in this effect.

  3. p21 is Responsible for Ionizing Radiation-induced Bypass of Mitosis.

    Science.gov (United States)

    Zhang, Xu Rui; Liu, Yong Ai; Sun, Fang; Li, He; Lei, Su Wen; Wang, Ju Fang

    2016-07-01

    To explore the role of p21 in ionizing radiation-induced changes in protein levels during the G2/M transition and long-term G2 arrest. 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. 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. 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. Copyright © 2016 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

  4. 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.

  5. 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)

  6. 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

  7. Multi-Level Effects of Low Dose Rate Ionizing Radiation on Southern Toad, Anaxyrus [Bufo] terrestris

    Science.gov (United States)

    Stark, Karolina; Scott, David E.; Tsyusko, Olga; Coughlin, Daniel P.; Hinton, Thomas G.

    2015-01-01

    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. PMID:25927361

  8. 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.

  9. Ionizing radiation measurements using low cost instruments for teaching in college or high-school in Brazil

    Science.gov (United States)

    Silva, M. C.; Vilela, D. C.; Migoto, V. G.; Gomes, M. P.; Martin, I. M.; Germano, J. S. E.

    2017-11-01

    Ionizing radiation one of modern physics experimental teaching in colleges and high school can be easily implemented today due to low coasts of detectors and also electronic circuits and data acquisition interfaces. First it is interesting to show to young’s students what is ionizing radiation and from where they appears near ground level? How it is possible to measure these radiations and how to check intensities variation during day, night, dry and wet periods in the same school? For increasing interest and stimulation in others students how to proceed in making the graphics of the ionizing radiation and presenting him in real time using Web internet facilities? Many others facilities like calibration of the detector using low intensities radioactive ionizing radiation sources, make comparison of the measurements and discussions of the results should be possible between many groups of students from several schools in the region of Brazil. This paper presents the experimental procedures including detectors and associated electronic including data acquisition, graphics elaboration and Web internet procedures to discuss and exchanging data measurements from several schools.

  10. 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.

  11. 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)

  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. Effects of ionizing radiation on DNA methylation: from experimental biology to clinical applications.

    Science.gov (United States)

    Miousse, Isabelle R; Kutanzi, Kristy R; Koturbash, Igor

    2017-05-01

    Ionizing radiation (IR) is a ubiquitous environmental stressor with genotoxic and epigenotoxic capabilities. Terrestrial IR, predominantly a low-linear energy transfer (LET) radiation, is being widely utilized in medicine, as well as in multiple industrial applications. Additionally, an interest in understanding the effects of high-LET irradiation is emerging due to the potential of exposure during space missions and the growing utilization of high-LET radiation in medicine. In this review, we summarize the current knowledge of the effects of IR on DNA methylation, a key epigenetic mechanism regulating the expression of genetic information. We discuss global, repetitive elements and gene-specific DNA methylation in light of exposure to high and low doses of high- or low-LET IR, fractionated IR exposure, and bystander effects. Finally, we describe the mechanisms of IR-induced alterations to DNA methylation and discuss ways in which that understanding can be applied clinically, including utilization of DNA methylation as a predictor of response to radiotherapy and in the manipulation of DNA methylation patterns for tumor radiosensitization.

  14. 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.

  15. Oligodendroglial response to ionizing radiation: Dose and dose-rate response

    Energy Technology Data Exchange (ETDEWEB)

    Levy, Richard P. [Univ. of California, Berkeley, CA (United States)

    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 γ-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.

  16. 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.

    2016-01-01

    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. PMID:27716640

  17. 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.

  18. Epigallocatechin-3-gallate (EGCG) protects skin cells from ionizing radiation via heme oxygenase-1 (HO-1) overexpression.

    Science.gov (United States)

    Zhu, Wei; Xu, Jing; Ge, Yangyang; Cao, Han; Ge, Xin; Luo, Judong; Xue, Jiao; Yang, Hongying; Zhang, Shuyu; Cao, Jianping

    2014-11-01

    Epigallocatechin-3-gallate (EGCG), the major polyphenolic constituent of green tea, is a potent antioxidant and free radical scavenger that may have therapeutic applications for the treatment of many disorders. Radiation therapy is widely used for the treatment of various types of cancers; however, radiation-induced skin injury remains a serious concern. EGCG has not yet been reported as protecting skin cells against ionizing radiation. In the present study, we investigated whether EGCG confers cytoprotection against ionizing radiation. We found that, compared with the control, pretreatment with EGCG significantly enhanced the viability of human skin cells that were irradiated with X-rays, and decreased apoptosis induced by X-ray irradiation. Mito-Tracker assay showed that EGCG suppressed the damage to mitochondria induced by ionizing radiation via upregulation of SOD2. Reactive oxygen species (ROS) in HaCaT cells were significantly reduced when pretreated with EGCG before irradiation. Radiation-induced γH2AX foci, which are representative of DNA double-strand breaks, were decreased by pretreatment with EGCG. Furthermore, EGCG induced the expression of the cytoprotective molecule heme oxygenase-1 (HO-1) in a dose-dependent manner via transcriptional activation. HO-1 knockdown or treatment with the HO-1 inhibitor tin protoporphyrin (SnPPIX) reversed the protective role of EGCG, indicating an important role for HO-1. These results suggest that EGCG offers a new strategy for protecting skin against ionizing radiation. © The Author 2014. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

  19. Overview of the atmospheric ionizing radiation environment monitoring by Bulgarian build instruments

    Science.gov (United States)

    Dachev, Tsvetan; Tomov, Borislav; Matviichuk, Yury; Dimitrov, Plamen; Spurny, Frantisek; Ploc, Ondrej; Uchihori, Yukio; Flueckiger, Erwin; Kudela, Karel; Benton, Eric

    2012-10-01

    Humans are exposed to ionizing radiation all the time, and it is known that it can induce a variety of harmful biological effects. Consequently, it is necessary to quantitatively assess the level of exposure to this radiation as the basis for estimating risks for their health. Spacecraft and aircraft crews are exposed to elevated levels of cosmic radiation of galactic and solar origin and to secondary radiation produced in the atmosphere, the vehicle structure and its contents. The aircraft crew monitoring is required by the following recommendations of the International Commission on Radiological Protection (ICRP) (ICRP 1990), the European Union (EU) introduced a revised Basic Safety Standards Directive (EC 1997) which, inter alia, included the exposure to cosmic radiation. This approach has been also adopted in other official documents (NCRP 2002). In this overview we present the results of ground based, mountain peaks, aircraft, balloon and rocket radiation environment monitoring by means of a Si-diode energy deposition spectrometer Liulin type developed first in Bulgarian Academy of Sciences (BAS) for the purposes of the space radiation monitoring at MIR and International Space Station (ISS). These spectrometers-dosemeters are further developed, calibrated and used by scientific groups in different countries. Calibration procedures of them are performed at different accelerators including runs in the CERN high-energy reference field, simulating the radiation field at 10 km altitude in the atmosphere and with heavy ions in Chiba, Japan HIMAC accelerator were performed also. The long term aircraft data base were accumulated using specially developed battery operated instrument in 2001-2009 years onboard of A310-300 aircrafts of Czech Air Lines, during 24 about 2 months runs with more than 2000 flights and 13500 flight hours on routes over the Atlantic Ocean mainly. The obtained experimental data are compared with computational models like CARI and EPCARD. The

  20. 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

  1. Ionizing radiation downregulates ASPM, a gene responsible for microcephaly in humans.

    Science.gov (United States)

    Fujimori, Akira; Yaoi, Takeshi; Ogi, Hiroshi; Wang, Bing; Suetomi, Katsutoshi; Sekine, Emiko; Yu, Dong; Kato, Takamitsu; Takahashi, Sentaro; Okayasu, Ryuichi; Itoh, Kyoko; Fushiki, Shinji

    2008-05-09

    Microcephaly is a malformation associated with in utero exposed atomic bomb survivors and can be induced in mice by fetal exposure to ionizing radiation (IR). The pathogenesis of IR-induced microcephaly, however, has not been fully understood. Our analyses of high-coverage expression profiling (HiCEP) demonstrated that the abnormal spindle-like microcephaly associated gene (ASPM) was down-regulated in irradiated human diploid fibroblasts. ASPM was recently reported as the causative gene for MCPH-5, the most common type of congenital microcephaly in humans. Here, we show that the expression of the Aspm gene was significantly reduced by IR in various human and murine cells. Additionally, Aspm was found downregulated in the irradiated fetal mouse brain, particularly in the ventricular zones. A similar suppression was observed in the irradiated neurosphere cultures. This is the first report suggesting that the suppression of Aspm by IR could be the initial molecular target leading to the future microcephaly formation.

  2. Defective repair of ionizing radiation damage in Cockayne`s syndrome and xeroderma pigmentosum group G

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, P.K. [Lawrence Berkeley Lab., CA (United States); Leadon, S.A. [Univ. of North Carolina, Chapel Hill, NC (United States)

    1994-12-31

    Damage produced by ultraviolet light (UV) or certain chemical carcinogens is repaired more rapidly in transcriptionally active DNA than in the genome as a whole by an evolutionarily conserved process coupled to transcription and involving preferential repair of transcribed strands. The generality of strand-specific repair for damage other than UV has not been well-established, but it has generally been assumed to involve the nucleotide excision repair pathway for bulky lesions. There is little overlap in the spectrum of lesions induced by ionizing radiation and UV; consistent with the idea that to a large extent, the repair processes for these two types of damage are separable, there are very few mammalian cell mutants that are hypersensitive to the lethal effects of both.

  3. 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.

  4. Ionizing radiation and legislation for personnel - Annex B; Radiacoes ionizantes e legislacao para trabalhadores - Anexo B

    Energy Technology Data Exchange (ETDEWEB)

    Delgado, Jose Ubiratan [Instituto de Radioprotecao e Dosimetria (LNMRI/IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. Nacional de Metrologia das Radiacoes Ionizantes

    2013-11-15

    This annex B presents a chronological approach on the set of laws related to the ionizing radiation personnel. This paper aims to discuss and clarify the main concepts that constitute the current legislation, pointing the scope of each, as well as its ambiguities or inaccuracies. The consequences of those issues discussed are easily noticeable related to difficulties in legal, administrative and human resource management, when seeking their efficient application. We also discuss issues associated with the extent and frequency of the gradient of risk in 5, 10 and 20%, models for assessing potential exposure in a risk area, dose calculation and criteria for defining benefits and framework for irradiation, bonus for activity, special retirement and period of vacations for personnel occupationally exposed within Unified Legal System (Regime Juridico Unico) and the Consolidation of Labor Laws (CLT)

  5. 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.

  6. Endothelial dysfunction in rectal cancer patients chronically exposed to ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Rakhypbekov, Tolebay; Pak, Laura; Chaizhunusova, Nailya; Manambayeva, Zukhra; Tokanova, Sholpan; Madiyeva, Madina [Semey State Medical University, Semey (Kazakhstan); Inoue, Ken [Kochi University, Health Service Center, Kochi (Japan); Kawano, Noriyuki; Hoshi, Masaharu [Hiroshima University, Hiroshima (Japan); Takeichi, Nobuo [Takeichi Clinic, Hiroshima (Japan); Noso, Yoshihiro [Shimane University, Department of General Surgery, Faculty of Medicine, Shimane (Japan); Khozhayev, Arman; Molgazhdarov, Maulen [The Kazakh National Medical University of S.D.Asfendiyarov, Department of Oncology, Almaty (Kazakhstan); Olzhaev, Sayakhat [Almaty Regional Oncologic Hospital, Department of Oncology, Almaty (Kazakhstan)

    2017-08-15

    We sought to identify the features of endothelial function in rectal cancer patients who were exposed to chronic ionizing radiation from a nuclear test site in Kazakhstan. We examined 146 individuals, 76 of whom were rectal cancer patients. The existence of a complex of disturbances of the endothelium and hemostasis systems in patients vs non-patients was revealed. Endothelial dysfunction was expressed as an increase of nitric oxide (NO) production along with decreases in vasodilatation function, and increased levels of von Willebrand factor in blood, along with an increase in the number of circulating endotheliocytes. Significant correlations between indicators of endothelial function and vascular-platelet hemostasis were observed. These changes and their interrelations were expressed more strongly in the patients who lived in the contaminated area around the nuclear test site. Such patients could have an increased risk of thrombosis and other complications after the treatment of a malignant neoplasm. (orig.)

  7. Non-ionizing radiation protection summary of research and policy options

    CERN Document Server

    Karipidis, Ken

    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...

  8. 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...... a high density of charge carriers in the core of particle tracks. As a consequence an increased (so called "initial") recombination of the charge carriers takes place, besides of the general (volume) recombination described by the Boag theory. A theory for a sub-type of initial recombination ("columnar......" recombination) is the Jaffe theory, which was developed in 1913 by Jaffe. He solved a differential equation by applying several simplifications and approximations such as a Gaussian shaped track whose width serves as free parameter. These simplifications and the use of an simplified charge carrier distribution...

  9. Pregnancy and exposure to ionizing radiations; Femme enceinte et exposition aux rayonnements ionisants

    Energy Technology Data Exchange (ETDEWEB)

    Topsoba, T.L. [Ouagadougou-Burkina Faso Univ., Lab. de Biophysique UFR/SDS (Burkina Faso); Tapsoba, T.L.; Cisse, R.; Lougue Sorgho, L.C.; Bamouni, Y.A. [Centre Hospitalier Universitaire Yo, Service de Radiologie et d' Imagerie Medicale (Burkina Faso); Gassama Seck, S. [Faculte de Medecine - UCAD, Dakar (Senegal)

    2006-06-15

    The sensitivity of the embryo and foetus varies during pregnancy. Recent studies confirm that the principal damage is mental retardation. It is generally admitted that the risk is negligible for a dose < 100 milli-sieverts (mSv). A possible termination of pregnancy will be considered for an exposure > 200 mSv.The objective of this work is to provide precise information on the various risks related to the irradiation for the foetus, according to the age of gestation and delivered dose, and the action to be taken in case of accidental irradiation. The medical use of ionizing radiation in pregnant women can only be considered within the framework of precise information. (author)

  10. Acetylation dynamics of human nuclear proteins during the ionizing radiation-induced DNA damage response

    DEFF Research Database (Denmark)

    Bennetzen, Martin V; Larsen, Dorthe Helena; Dinant, Christoffel

    2013-01-01

    -dependent posttranslational modifications (PTMs). To complement our previous analysis of IR-induced temporal dynamics of nuclear phosphoproteome, we now identify a range of human nuclear proteins that are dynamically regulated by acetylation, and predominantly deacetylation, during IR-induced DDR by using mass spectrometry...... to genotoxic insults. Overall, these results present a resource of temporal profiles of a spectrum of protein acetylation sites during DDR and provide further insights into the highly dynamic nature of regulatory PTMs that help orchestrate the maintenance of genome integrity.......Genotoxic insults, such as ionizing radiation (IR), cause DNA damage that evokes a multifaceted cellular DNA damage response (DDR). DNA damage signaling events that control protein activity, subcellular localization, DNA binding, protein-protein interactions, etc. rely heavily on time...

  11. 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.

  12. 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.

  13. Acceleration of skin wound healing by low-dose indirect ionizing radiation in male rats

    Directory of Open Access Journals (Sweden)

    Nasrollah Jabbari

    2017-08-01

    Full Text Available A recent hypothesis has revealed that low-dose irradiation (LDI with ionizing radiation might have a promoting effect on fracture healing. The aim of this study was to investigate the influence of direct (electron beam and indirect (gamma-ray low-dose ionizing irradiations on the wound healing process in male rats. In 72 male rats, a full-thickness wound was incised. The animals were randomly assigned to three groups, each with 24 rats. The first two groups were named IG–I and IG–II and respectively exposed to electron and gamma-radiations (75 cGy immediately after the surgical procedure. The third group was considered as the control (CG and remained untreated. Skin biopsies from the subgroups were collected on days 3, 7, 15, and 21 after the operation and evaluated using histological and biomechanical methods. Data were analyzed by one-way ANOVA, followed by Tukey's post hoc test using SPSS 20 software. Histological studies of tissues showed that the mean number of fibroblasts, macrophages, blood vessel sections, and neutrophils on the third and seventh days after the surgery in the gamma-treated group was higher than that in both other groups. In contrast, on day 21, the mean number of mentioned cells in the gamma-treated group was lower than in the other two groups. In addition, the mean maximum stress value was significantly greater in the gamma-treated group. Results of this study showed that gamma-ray irradiation is effective in the acceleration of wound healing.

  14. Increased Transgenerational Intestinal Tumorigenesis in Offspring of Ionizing Radiation Exposed Parent APC1638N/+ Mice.

    Science.gov (United States)

    Suman, Shubhankar; Kumar, Santosh; Moon, Bo-Hyun; Fornace, Albert J; Kallakury, Bhaskar V S; Datta, Kamal

    2017-01-01

    The purpose of the study was to assess transgenerational intestinal tumorigenic effects of low dose ionizing radiation employing a well-characterized mouse model of human colorectal cancer. Mice (6 to 8 weeks old APC1638N/+ mice; n=20 per study group) were exposed to whole-body 25 cGy x-rays and mated 2 days post-irradiation. Intestinal tumorigenesis in male and female F1 mice from No Parents Irradiated (NPI), Both Parents Irradiated (BPI), and Male Parent Irradiated (MPI) groups were compared 210 days after birth. Male and female Direct Parent Irradiated (DPI) groups were additional controls for male and female F1 groups respectively. Data showed higher intestinal tumor frequency (± standard error of the mean) in male and female F1 from BPI (male: 7.81 ± 0.91; female: 5.45 ± 0.36) as well as from MPI (male: 6.30 ± 0.33; female: 4.45 ± 0.33) mice relative to F1 from NPI mice (male: 4.2 ± 0.48; female: 3.35 ± 0.37). Compared to male and female DPI (male: 5.55 ± 0.40; female: 3.60 ± 0.22), tumor frequency in F1 mice of BPI and MPI, though higher, was not statistically significant except for DPI vs. BPI in male mice. Additionally, both BPI and MPI showed increased frequency of larger tumors relative to NPI. In summary, our observations demonstrated that the APC1638N/+ mice due to its low spontaneous tumor frequency could serve as an effective model to study risk of transgenerational carcinogenesis in gastrointestinal tissues after exposure to clinically relevant low doses of ionizing radiation.

  15. 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

  16. 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)

  17. 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

  18. Radiation-induced cell transformation: transformation efficiencies of different types of ionizing radiation and molecular changes in radiation transformants and tumor cell lines.

    OpenAIRE

    Hieber, L.; Trutschler, K; Smida, J.; Wachsmann, M; Ponsel, G.; Kellerer, Albrecht M.

    1990-01-01

    This study aims to compare the efficiencies of 5.4 keV soft X-rays, alpha-particles, and gamma-rays in transforming C3H 10T1/2 cells and to assess the sequence of cellular and molecular changes during the process of radiation-induced transformation of Syrian hamster embryo (SHE) cells. The somewhat more densely ionizing soft X-rays are more effective than gamma-rays both for cell inactivation and cell transformation. The relative biological effectiveness (RBE) appears to be independent of dos...

  19. Parametrization of the average ionization and radiative cooling rates of carbon plasmas in a wide range of density and temperature

    OpenAIRE

    Gil de la Fe, Juan Miguel; Rodriguez Perez, Rafael; Florido, Ricardo; Garcia Rubiano, Jesus; Mendoza, M. A.; Nuez, A. de la; Espinosa, G.; Martel Escobar, Carlos; Mínguez Torres, Emilio

    2013-01-01

    In this work we present an analysis of the influence of the thermodynamic regime on the monochromatic emissivity, the radiative power loss and the radiative cooling rate for optically thin carbon plasmas over a wide range of electron temperature and density assuming steady state situations. Furthermore, we propose analytical expressions depending on the electron density and temperature for the average ionization and cooling rate based on polynomial fittings which are valid for the whole range...

  20. 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.)

  1. Interpopulational variability of molecular responses to ionizing radiation in freshwater bivalves Anodonta anatina (Unionidae)

    Energy Technology Data Exchange (ETDEWEB)

    Falfushynska, H. [Research Laboratory of Comparative Biochemistry and Molecular Biology, Ternopil National Pedagogical University, 2, Kryvonosa Str, Ternopil 46027 (Ukraine); Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223 (United States); Department of General Chemistry, I.Ya. Horbachevsky Ternopil State Medical University, 1, Maidan Voli, Ternopil 46001 (Ukraine); Gnatyshyna, L. [Research Laboratory of Comparative Biochemistry and Molecular Biology, Ternopil National Pedagogical University, 2, Kryvonosa Str, Ternopil 46027 (Ukraine); Department of General Chemistry, I.Ya. Horbachevsky Ternopil State Medical University, 1, Maidan Voli, Ternopil 46001 (Ukraine); Yurchak, I.; Stoliar, O. [Research Laboratory of Comparative Biochemistry and Molecular Biology, Ternopil National Pedagogical University, 2, Kryvonosa Str, Ternopil 46027 (Ukraine); Sokolova, I.M., E-mail: isokolova@uncc.edu [Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223 (United States)

    2016-10-15

    Freshwater ecosystems are exposed to multiple anthropogenic stressors including chemical pollution and warming that can affect health of the resident organisms and their responses to novel challenges. We investigated the of in situ exposure history on molecular responses to a novel stressor, ionizing radiation, in unionid mollusks Anodonta anatina. Males from pristine (F-), agricultural (A-) sites and a cooling reservoir of a nuclear power plant (N-site) were exposed to acute low dose (2 mGy) X-ray radiation followed by 14 days of recovery (R-groups) or to control conditions (C-groups). Biomarkers of oxidative stress, geno-, cyto- and neurotoxicity were used to assess cellular injury and stress. Control group from the cooling reservoir (CN) had higher background levels of caspase-3 activity, metallothionein concentrations and nuclear lesions and lower levels of superoxide dismutase (SOD) and glutathione in the gills compared to other control groups (CF and CA). Irradiation induced cellular damage in mussels from all three sites including increased levels of nuclear lesions in hemocytes, depletion of caspase-3, suppression of superoxide dismutase and catalase activities, an increase of the lipid peroxidation and oxidized glutathione levels, as well as down-regulation of cholinesterase indicating neurotoxicity. The up-regulation of ethoxyresorufin-O-deethylase activity in the digestive gland and vitellogenin-like protein level in gonads were also found in radiation-exposed groups indicating feminization of males and disturbances of xenobiotic metabolism. The RA-group showed the greatest magnitude of radiation-induced stress responses compared to the other two groups. Overall, unionid mollusks, particularly those from a chronically polluted agricultural site, were highly sensitive to low-dose radiation (2 mGy) indicating limitations of stress protection mechanisms to deal with multiple stressors. - Highlights: • Habitat-specific effects of irradiation were studied

  2. 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

  3. Is natural radioactivity and ionizing radiation necessary for us and our earth?; Sind (natuerliche) Radioaktivitaet und ionisierende Strahlung fuer uns und unsere Erde notwendig?

    Energy Technology Data Exchange (ETDEWEB)

    Voelkle, Hansruedi [Fribourg Univ. (Switzerland). Physikdepartement

    2017-04-01

    Artificial radioactive materials and ionizing radiation are used in medicine, industry and science. Is there also a purpose in the sense of Aristoteles that nothing on earth is unnecessary? The contribution discusses examples of natural radioactivity in the atmosphere, the production of geothermal energy and the role of radioactivity and ionizing radiation in evolution.

  4. 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

  5. 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.

  6. 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.

  7. MDP: A Deinococcus Mn2+-Decapeptide Complex Protects Mice from Ionizing Radiation.

    Directory of Open Access Journals (Sweden)

    Paridhi Gupta

    Full Text Available 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.

  8. 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...

  9. 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

  10. 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.

  11. 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.

  12. Non-targeted and delayed effects of exposure to ionizing radiation: II. Radiation-induced genomic instability and bystander effects in vivo, clastogenic factors and transgenerational effects

    Science.gov (United States)

    Morgan, William F.

    2003-01-01

    The goal of this review is to summarize the evidence for non-targeted and delayed effects of exposure to ionizing radiation in vivo. Currently, human health risks associated with radiation exposures are based primarily on the assumption that the detrimental effects of radiation occur in irradiated cells. Over the years a number of non-targeted effects of radiation exposure in vivo have been described that challenge this concept. These include radiation-induced genomic instability, bystander effects, clastogenic factors produced in plasma from irradiated individuals that can cause chromosomal damage when cultured with nonirradiated cells, and transgenerational effects of parental irradiation that can manifest in the progeny. These effects pose new challenges to evaluating the risk(s) associated with radiation exposure and understanding radiation-induced carcinogenesis.

  13. 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

  14. New approaches in clinical application of laser-driven ionizing radiation

    Science.gov (United States)

    Hideghéty, Katalin; Szabó, Rita Emilia; Polanek, Róbert; Szabó, Zoltán.; Brunner, Szilvia; Tőkés, Tünde

    2017-05-01

    The planned laser-driven ionizing beams (photon, very high energy electron, proton, carbon ion) at laser facilities have the unique property of ultra-high dose rate (>Gy/s-10), short pulses, and at ELI-ALPS high repetition rate, carry the potential to develop novel laser-driven methods towards compact hospital-based clinical application. The enhanced flexibility in particle and energy selection, the high spatial and time resolution and extreme dose rate could be highly beneficial in radiotherapy. These approaches may increase significantly the therapeutic index over the currently available advanced radiation oncology methods. We highlight two nuclear reactionbased binary modalities and the planned radiobiology research. Boron Neutron Capture Therapy is an advanced cell targeted modality requiring 10B enriched boron carrier and appropriate neutron beam. The development of laser-based thermal and epithermal neutron source with as high as 1010 fluence rate could enhance the research activity in this promising field. Boron-Proton Fusion reaction is as well as a binary approach, where 11B containing compounds are accumulated into the cells, and the tumour selectively irradiated with protons. Due to additional high linear energy transfer alpha particle release of the BPFR and the maximum point of the Bragg-peak is increased, which result in significant biological effect enhancement. Research at ELI-ALPS on detection of biological effect differences of modified or different quality radiation will be presented using recently developed zebrafish embryo and rodent models.

  15. 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.

  16. Ionizing radiation-induced bystander mutagenesis and adaptation: Quantitative and temporal aspects

    Science.gov (United States)

    Zhang, Ying; Zhou, Junqing; Baldwin, Joseph; Held, Kathryn D; Prise, Kevin M; Redmond, Robert W.; Liber, Howard L.

    2009-01-01

    This work explores several quantitative aspects of radiation-induced bystander mutagenesis in WTK1 human lymphoblast cells. Gamma-irradiation of cells was used to generate conditioned medium containing bystander signals, and that medium was transferred onto naïve recipient cells. Kinetic studies revealed that it required up to one hour to generate sufficient signal to induce the maximal level of mutations at the thymidine kinase locus in the bystander cells receiving the conditioned medium. Furthermore, it required at least one hour of exposure to the signal in the bystander cells to induce mutations. Bystander signal was fairly stable in the medium, requiring 12–24 hours to diminish. Medium that contained bystander signal was rendered ineffective by a 4-fold dilution; in contrast a greater than 20-fold decrease in the cell number irradiated to generate a bystander signal was needed to eliminate bystander-induced mutagenesis. This suggested some sort of feedback inhibition by bystander signal that prevented the signaling cells from releasing more signal. Finally, an ionizing radiation-induced adaptive response was shown to be effective in reducing bystander mutagenesis; in addition, low levels of exposure to bystander signal in the transferred medium induced adaptation that was effective in reducing mutations induced by subsequent γ-ray exposures. PMID:19695271

  17. Ionizing radiation-induced bystander mutagenesis and adaptation: Quantitative and temporal aspects

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Ying; Zhou Junqing; Baldwin, Joseph [Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO (United States); Held, Kathryn D. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); Prise, Kevin M. [Centre for Cancer Research and Cell Biology, Queen' s University Belfast, Belfast (United Kingdom); Redmond, Robert W. [Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA (United States); Liber, Howard L., E-mail: howard.liber@colostate.edu [Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO (United States); University of Colorado Cancer Center, Denver, CO (United States)

    2009-12-01

    This work explores several quantitative aspects of radiation-induced bystander mutagenesis in WTK1 human lymphoblast cells. Gamma-irradiation of cells was used to generate conditioned medium containing bystander signals, and that medium was transferred onto naive recipient cells. Kinetic studies revealed that it required up to 1 h to generate sufficient signal to induce the maximal level of mutations at the thymidine kinase locus in the bystander cells receiving the conditioned medium. Furthermore, it required at least 1 h of exposure to the signal in the bystander cells to induce mutations. Bystander signal was fairly stable in the medium, requiring 12-24 h to diminish. Medium that contained bystander signal was rendered ineffective by a 4-fold dilution; in contrast a greater than 20-fold decrease in the cell number irradiated to generate a bystander signal was needed to eliminate bystander-induced mutagenesis. This suggested some sort of feedback inhibition by bystander signal that prevented the signaling cells from releasing more signal. Finally, an ionizing radiation-induced adaptive response was shown to be effective in reducing bystander mutagenesis; in addition, low levels of exposure to bystander signal in the transferred medium induced adaptation that was effective in reducing mutations induced by subsequent {gamma}-ray exposures.

  18. Metabolomic Response of Human Skin Tissue to Low Dose Ionizing Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Zeping; Kim, Young-Mo; Sowa, Marianne B.; Robinson, Robert J.; Gao, Xiaoli; Metz, Thomas O.; Morgan, William F.; Zhang, Qibin

    2012-05-18

    Understanding how human organs respond to ionizing radiation (IR) at a systems biology level and identifying biomarkers for IR exposure at low doses can help provide a scientific basis for establishing radiation protection standards. Little is known regarding the physiological responses to low dose IR at the metabolite level, which represents the end-point of biochemical processes inside cells. Using a full thickness human skin tissue model and GC-MS-based metabolomics analysis, we examined the metabolic perturbations at three time points (3, 24 and 48 hr) after exposure to 3, 10 and 200 cGy of X-rays. PLS-DA score plots revealed dose- and time-dependent clustering between sham and irradiated groups. Importantly, a comparable number of metabolites were detected to have significant change 48 hr after exposure to 3 and 10 cGy of irradiation, when compared with the high dose of 200 cGy. Biochemical pathway analysis showed perturbations to DNA/RNA damage and repair, lipid and energy metabolisms, even at low doses of IR.

  19. 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)

  20. 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. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. 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.

  2. Atomic xenon recombination laser excited by thermal ionizing radiation from a magnetoplasma compressor and discharge

    Science.gov (United States)

    Kamrukov, A. S.; Kozlov, Nicolay P.; Opekan, A. G.; Protasov, Yuri S.; Rudoi, I. G.; Soroka, A. M.

    1991-09-01

    A description is given and the results are reported of the first photoionization-recombination laser using atomic xenon excited by thermal ionizing radiation from a plasma. The pump source was a multichannel plasmadynamic in magnetoplasma compressors, which was ignited in the active medium of the laser. When the composition of the working mixture was optimal (Xe:Ar equals 1:250) and the total pressure was 1 atm, the output energy was approximately 0.5 in the form of pulses of approximately 10 microsecond(s) duration, and maximum specific output energy represented by laser radiation was 1-2 J/l. The unsaturated gain was 27 m. A kinetic laser scheme was proposed and analyzed. It allowed for the processes of photoionization, ion conversion, dissociative recombination, interaction of excited states with electron and buffer gases, etc. An important role played by heating of the active medium during pumping was demonstrated; it explained the observed characteristics of the spatial and temporal structure of the lasing process, particularly bleaching of large volumes of the active medium. The potential output energy of the laser was considered, and specific constructions were proposed to attain a lasing efficiency amounting to a few percent.

  3. LASERS: Atomic xenon recombination laser excited by thermal ionizing radiation from a magnetoplasma compressor and discharge

    Science.gov (United States)

    Kamrukov, A. S.; Kozlov, N. P.; Opekan, A. G.; Protasov, Yu S.; Rudoĭ, I. G.; Soroka, A. M.

    1989-07-01

    A description is given and the results are reported of the first photoionization-recombination laser using atomic xenon excited by thermal ionizing radiation from a plasma. The pump source was a multichannel plasmadynamic discharge in magnetoplasma compressors, which was ignited in the active medium of the laser. When the composition of the working mixture was optimal (Xe:Ar = 1:250) and the total pressure was 1 atm, the output energy was ~ 0.5 J in the form of pulses of ~ 10 μs duration and the maximum specific output energy represented by laser radiation was 1-2 J/liter. The unsaturated gain was 27 m - 1. A kinetic laser scheme was proposed and analyzed. It allowed for the processes of photoionization, ion conversion, dissociative recombination, interaction of excited states with electron and buffer gases, etc. An important role played by heating of the active medium during pumping was demonstrated and it explained the observed characteristics of the spatial and temporal structure of the lasing process, particularly bleaching of large volumes of the active medium. The potential output energy of the laser was considered and specific constructions were proposed to attain a lasing efficiency amounting to a few percent.

  4. Ionizing radiation effects on the secretory-stage ameloblasts and enamel organic extracellular matrix.

    Science.gov (United States)

    de Moraes Ramos-Perez, Flávia Maria; do Espírito Santo, Alexandre Ribeiro; da Cruz Perez, Danyel Elias; Novaes, Pedro Duarte; Bóscolo, Frab Norberto; Line, Sérgio Roberto Peres; de Almeida, Solange Maria

    2014-08-01

    This study assessed the effects of high doses of ionizing radiation on eruption rate, odontogenic region morphology, secretory-stage ameloblasts, and enamel organic extracellular matrix (EOECM) of rat maxillary incisors. For the study, 30 male rats were divided into three experimental groups: control (non-irradiated), irradiated by 15 Gy, and irradiated by 25 Gy. Irradiated groups received a single dose of 15 or 25 Gy of X-rays in the head and neck region. The maxillary incisor eruption rate was measured. Sections of 5-µm thickness of the maxillary incisor odontogenic regions were evaluated using bright field light microscopy. Ultrathin sections of secretory ameloblasts and their EOECM were analyzed by transmission electron microscopy (TEM). Irradiated groups showed significantly diminished eruption rate values at the 4th and at the 6th day after irradiation. Reduced optical retardation values were observed in the irradiated groups. The odontogenic region of maxillary incisors from irradiated rats exhibited altered and poorly organized preameloblasts. TEM showed degeneration areas in the secretory-stage EOECM and several autophagosomes in the secretory ameloblasts from irradiated animals. In conclusion, high radiation doses delay eruption and induce disturbances in secretory ameloblasts and EOECM of rat maxillary incisors. These findings may be associated with structural defects of mature enamel.

  5. 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.

  6. Potential Treatment of Inflammatory and Proliferative Diseases by Ultra-Low Doses of Ionizing Radiations

    Science.gov (United States)

    Sanders, Charles L.

    2012-01-01

    Ultra-low doses and dose- rates of ionizing radiation are effective in preventing disease which suggests that they also may be effective in treating disease. Limited experimental and anecdotal evidence indicates that low radiation doses from radon in mines and spas, thorium-bearing monazite sands and enhanced radioactive uranium ore obtained from a natural geological reactor may be useful in treating many inflammatory conditions and proliferative disorders, including cancer. Optimal therapeutic applications were identified via a literature survey as dose-rates ranging from 7 to 11μGy/hr or 28 to 44 times world average background rates. Rocks from an abandoned uranium mine in Utah were considered for therapeutic application and were examined by γ-ray and laser-induced breakdown fluorescence spectroscopy. The rocks showed the presence of transuranics and fission products with a γ-ray energy profile similar to aged spent uranium nuclear fuel (93% dose due to β particles and 7% due to γ rays). Mud packs of pulverized uranium ore rock dust in sealed plastic bags delivering bag surface β,γ dose-rates of 10–450 μGy/h were used with apparent success to treat several inflammatory and proliferative conditions in humans. PMID:23304108

  7. The regulatory effects of low-dose ionizing radiation on Ikaros-autotaxin interaction

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Hana; Cho, Seong Jun; Kim, Sung Jin; Nam, Seon Young; Yang, Kwang Hee [KHNP Radiation Health Institute, Korea Hydro and Nuclear Power Co, Seoul (Korea, Republic of)

    2016-11-15

    Ikaros, a transcription factor containing zinc-finger motif, has known as a critical regulator of hematopoiesis in immune system. Ikaros protein modulates the transcription of target genes via binding to the regulatory elements of the genes promoters. However the regulatory function of Ikaros in other organelle except nuclear remains to be determined. This study explored radiation-induced modulatory function of Ikaros in cytoplasm. The results showed that Ikaros protein lost its DNA binding ability after LDIR (low-dose ionizing radiation) exposure. Cell fractionation and Western blot analysis showed that Ikaros protein was translocated into cytoplasm from nuclear by LDIR. This was confirmed by immunofluorescence assay. We identified Autotaxin as a novel protein which potentially interacts with Ikaros through in vitro protein-binding screening. Co-immunoprecipitation assay revealed that Ikaros and Autotaxin are able to bind each other. Autotaxin is a crucial enzyme generating lysophosphatidic acid (LPA), a phospholipid mediator, which has potential regulatory effects on immune cell growth and motility. Our results indicate that LDIR potentially regulates immune system via protein-protein interaction of Ikaros and Autotaxin.

  8. Use of GaN as a Scintillating Ionizing Radiation Detector

    Science.gov (United States)

    Wensman, Johnathan; Guardala, Noel; Mathur, Veerendra; Alasagas, Leslie; Vanhoy, Jeffrey; Statham, John; Marron, Daniel; Millett, Marshall; Marsh, Jarrod; Currie, John; Price, Jack

    2017-09-01

    Gallium nitride (GaN) is a III/V direct bandgap semiconductor which has been used in light emitting diodes (LEDs) since the 1990s. Currently, due to a potential for increased efficiency, GaN is being investigated as a replacement for silicon in power electronics finding potential uses ranging from data centers to electric vehicles. In addition to LEDs and power electronics though, doped GaN can be used as a gamma insensitive fast neutron detector due to the direct band-gap, light propagation properties, and response to ionizing radiations. Investigation of GaN as a semiconductor scintillator for use in a radiation detection system involves mapping the response function of the detector crystal over a range of photon and neutron energies, and measurements of light generation in the GaN crystal due to proton, alpha, and nitrogen projectiles. In this presentation we discuss the measurements made to date, and plausible interpretations of the response functions. This work funded in part by the Naval Surface Warfare Center, Carderock Division In-house Laboratory Independent Research program.

  9. Identification and characterization of secretory proteins during ionizing radiation-induced premature senescence

    Energy Technology Data Exchange (ETDEWEB)

    Han, Na Kyung; Hong, Mi Na; Jung, Seung Hee; Kang, Kyoung Ah; Lee, Jae Seon [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Chi, Seong Gil [Korea University, Seoul (Korea, Republic of)

    2011-05-15

    Cellular senescence was first described by Hayflick and Moorhead in 1961 who observed that cultures of normal human fibroblasts had a limited replicative potential and eventually became irreversibly arrest. The majority of senescent cells assume a characteristic flattened and enlarged morphological change, senescence associated {beta} alactosidase positivity. Recently a large number of molecular phenotypes such as changes in gene expression, protein processing and chromatin organization have been also described. In contrast to apoptosis, senescence does not destroy the cells but leaves them metabolically and synthetically active and therefore able to affect their microenvironment. In particular, senescent fibroblasts and some cancer cells were found to secrete proteins with known or putative tumor-promoting functions such as growth factors or proteolytic enzymes. However, the knowledge about secreted proteins from senescent tumor cells and their functions to surrounding cells is still lacking. In this study, changes of senescence associated secretory protein expression profile were observed in MCF7 human breast cancer cells exposed to gamma-ray radiation using two dimensional electrophoresis. Also, we identified up-regulated secretory proteins during ionizing radiation-induced cellular senescence. Here, we show that senescent human breast cancer MCF7 cells promote the proliferation, invasion and migration of neighboring cells

  10. Identification of Secreted Proteins from Ionizing Radiation-Induced Senescent MCF7 Cells Using Comparative Proteomics

    Energy Technology Data Exchange (ETDEWEB)

    Han, Na Kyung; Kim, Han Na; Hong, Mi Na; Park, Su Min; Lee, Jae Seon [Korea Institue of Radiological and Medical Sciences, Seoul (Korea, Republic of); Chi, Seong Gil [Korea University, Seoul (Korea, Republic of)

    2010-05-15

    Cellular senescence was first described by Hayflick and Moorhead in 1961 who observed that cultures of normal human fibroblasts had a limited replicative potential and eventually became irreversibly arrest. The majority of senescent cells assume a characteristic flattened and enlarged morphological change, senescence associated beta-galactosidase positivity and over the years a large number of molecular phenotypes have been described, such as changes in gene expression, protein processing and chromatin organization. In contrast to apoptosis, senescence does not destroy the cells but leaves them metabolically and synthetically active and therefore able to affect their microenvironment. In particular, senescent fibroblasts and some cancer cells were found to secrete proteins with known or putative tumor-promoting functions such as growth factors or proteolytic enzymes. However, the knowledge about secreted proteins from senescent tumor cells and their functions to surrounding cells is still lacking. In this study, changes of senescence-associated secretory protein expression profile were observed in MCF7 human breast cancer cells exposed to gamma-ray radiation using two dimensional electrophoresis. Also, we identified up-regulated secretory proteins during ionizing radiation-induced cellular senescence

  11. Risk of Ionizing Radiation in Women of Childbearing Age undergoing Radiofrequency Ablation

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Gustavo Glotz de, E-mail: gglima.pesquisa@gmail.com; Gomes, Daniel Garcia; Gensas, Caroline Saltz; Simão, Mariana Fernandez; Rios, Matheus N.; Pires, Leonardo Martins; Kruse, Marcelo Lapa; Leiria, Tiago Luiz Luz [Instituto de Cardiologia, Fundação Universitária de Cardiologia, Porto Alegre, RS (Brazil)

    2013-11-15

    The International Commission of Radiology recommends a pregnancy screening test to all female patients of childbearing age who will undergo a radiological study. Radiation is known to be teratogenic and its effect is cumulative. The teratogenic potential starts at doses close to those used during these procedures. The prevalence of positive pregnancy tests in patients undergoing electrophysiological studies and/or catheter ablation in our midst is unknown. To evaluate the prevalence of positive pregnancy tests in female patients referred for electrophysiological study and/or radiofrequency ablation. Cross-sectional study analyzing 2,966 patients undergoing electrophysiological study and/or catheter ablation, from June 1997 to February 2013, in the Institute of Cardiology of Rio Grande do Sul. A total of 1490 procedures were performed in women, of whom 769 were of childbearing age. All patients were screened with a pregnancy test on the day before the procedure. Three patients tested positive, and were therefore unable to undergo the procedure. The prevalence observed was 3.9 cases per 1,000 women of childbearing age. Because of their safety and low cost, pregnancy screening tests are indicated for all women of childbearing age undergoing radiological studies, since the degree of ionizing radiation needed for these procedures is very close to the threshold for teratogenicity, especially in the first trimester, when the signs of pregnancy are not evident.

  12. Survival, DNA Integrity, and Ultrastructural Damage in Antarctic Cryptoendolithic Eukaryotic Microorganisms Exposed to Ionizing Radiation.

    Science.gov (United States)

    Pacelli, Claudia; Selbmann, Laura; Zucconi, Laura; Raguse, Marina; Moeller, Ralf; Shuryak, Igor; Onofri, Silvano

    2017-02-01

    Life dispersal between planets, planetary protection, and the search for biosignatures are main topics in astrobiology. Under the umbrella of the STARLIFE project, three Antarctic endolithic microorganisms, the melanized fungus Cryomyces antarcticus CCFEE 515, a hyaline strain of Umbilicaria sp. (CCFEE 6113, lichenized fungus), and a Stichococcus sp. strain (C45A, green alga), were exposed to high doses of space-relevant gamma radiation (60Co), up to 117.07 kGy. After irradiation survival, DNA integrity and ultrastructural damage were tested. The first was assessed by clonogenic test; viability and dose responses were reasonably described by the linear-quadratic formalism. DNA integrity was evaluated by PCR, and ultrastructural damage was observed by transmission electron microscopy. The most resistant among the tested organisms was C. antarcticus both in terms of colony formation and DNA preservation. Besides, results clearly demonstrate that DNA was well detectable in all the tested organisms even when microorganisms were dead. This high resistance provides support for the use of DNA as a possible biosignature during the next exploration campaigns. Implication in planetary protection and contamination during long-term space travel are put forward. Key Words: Biosignatures-Ionizing radiation-DNA integrity-Eukaryotic microorganisms-Fingerprinting-Mars exploration. Astrobiology 17, 126-135.

  13. Effect of high dose natural ionizing radiation on the immune system of the exposed residents of Ramsar Town, Iran.

    Science.gov (United States)

    Attar, Massoud; Molaie Kondolousy, Yaghob; Khansari, Nemat

    2007-06-01

    Iran is one of several countries that has regions of high dose natural ionizing radiation. Two well-known villages 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 to study 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 significantly lower than the individuals not exposed to high dose natural ionizing radiation. The exposed individuals also had higher lymphocyte-induced IL-4 and IL-10 production, and lower IL-2 and IFN-gamma 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 has adapted to its environment by shifting from a Type 1 to a Type 2 response to promote anti-inflammation. This may be because inflammatory Type 1 responses generate more free radicals than Type 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.

  14. 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

  15. NMR-based Metabolomics Analysis of Liver from C57BL/6 Mouse Exposed to Ionizing Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Xiongjie [Pacific Northwest National Laboratory, Richland, Washington 99352; State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, the Chinese Academy of Sciences, Wuhan, 430071, PR China; University of Chinese Academy of Sciences, Beijing 100049, China; Hu, Mary [Pacific Northwest National Laboratory, Richland, Washington 99352; Zhang, Xu [State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, the Chinese Academy of Sciences, Wuhan, 430071, PR China; Hu, Jian Zhi [Pacific Northwest National Laboratory, Richland, Washington 99352

    2017-07-01

    The health effects of exposing to ionizing radiation are attracting great interest in the space exploration community and patients considering radiotherapy. However, the impact to metabolism after exposure to high dose radiation has not yet been clearly defined in livers. In the present study, 1H nuclear magnetic resonance (NMR) based metabolomics combined with multivariate data analysis are applied to study the changes of metabolism in the liver of C57BL/6 mouse after whole body exposure to either gamma (3.0 and 7.8 Gy) or proton (3.0 Gy) radiation. Principal component analysis (PCA) and orthogonal projection to latent structures analysis (OPLS) are employed for classification and identification of potential biomarkers associated with gamma and proton irradiation. The results show that the radiation exposed groups can be well separated from the control group. At the same radiation dosage, the group exposed to proton radiation is well separated from the group exposed to gamma radiation, indicating different radiation sources induce different alterations based on metabolic profiling. Common to both gamma and proton radiation at the high radiation doses studied in this work, compared with the control groups the concentrations of choline, O-phosphocholine and trimethylamine N-oxide are decreased statistically, while those of glutamine, glutathione, malate, creatinine, phosphate, betaine and 4-hydroxyphenylacetate are statistically and significantly elevated after exposure to radiation. Since these altered metabolites are associated with multiple biological pathways, the changes suggest that the exposure to radiation induce abnormality in multiple biological pathways. In particular, metabolites such as 4-hydroxyphenylacetate, betaine, glutamine, choline and trimethylamine N-oxide may be good candidates of pre-diagnose biomarkers for ionizing radiation in liver.

  16. Derivation of radiation quality average parameters in neutron-gamma radiation fields with the high-pressure ionization chamber: theory and practice.

    Science.gov (United States)

    Makrigiorgos, G M

    1989-06-01

    The established radiation quality parameters in mixed neutron-gamma radiation fields may be measured by applying the initial (columnar) recombination of ions in tissue-equivalent (TE) high-pressure ionization chambers (recombination chambers). The mean quality factor can be determined to within 10-15% for mixed fields with neutrons ranging from thermal to 10 MeV, and the dose mean LET of the proton component can be determined to within 10-15% if the gamma-ray absorbed dose fraction is known. These average parameters are derived by measuring the ratio of the ionization currents collected at two high-field strengths and constant gas pressure applied to the ionization chamber. By utilizing approximate correlations between physical parameters in the neutron energy region from thermal to 10 MeV, the dose mean LET of the heavy ion component, the overall dose mean LET, and the microdosimetric parameter y0,D of the mixed field can also be derived. Experimental verification of the method is presented for various neutron-gamma radiation spectra in air and in water by comparison to theoretical calculations and results from low-pressure proportional counter measurements. Good agreement is shown. The TE high-pressure ionization chamber appears to have wide potential for use as a dose-equivalent meter in radiation protection or as a beam characterization device in radiobiology.

  17. 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.

  18. 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