WorldWideScience

Sample records for investigate radiation damage

  1. Investigation of damage mechanism by ionising radiation on biomolecules

    International Nuclear Information System (INIS)

    Lau How Mooi

    1996-01-01

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

  2. Radiation damage

    CERN Document Server

    Heijne, Erik H M; CERN. Geneva

    1998-01-01

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

  3. High dose radiation damage in nuclear energy structural materials investigated by heavy ion irradiation simulation

    International Nuclear Information System (INIS)

    Zheng Yongnan; Xu Yongjun; Yuan Daqing

    2014-01-01

    Structural materials in ITER, ADS and fast reactor suffer high dose irradiations of neutrons and/or protons, that leads to severe displacement damage up to lOO dpa per year. Investigation of radiation damage induced by such a high dose irradiation has attracted great attention along with the development of nuclear energy facilities of new generation. However, it is deeply hampered for the lacking of high dose neutron and proton sources. Irradiation simulation of heavy ions produced by accelerators opens up an effective way for laboratory investigation of high dose irradiation induced radiation damage encountered in the ITER, ADS, etc. Radiation damage is caused mainly by atomic displacement in materials. The displacement rate of heavy ions is about lO 3 ∼10 7 orders higher than those of neutrons and protons. High displacement rate of heavy ions significantly reduces the irradiation time. The heavy ion irradiation simulation technique (HIIS) technique has been developed at China Institute of Atomic Energy and a series of the HIIS experiments have been performed to investigate radiation damage in stainless steels, tungsten and tantalum at irradiation temperatures from room temperature to 800 ℃ and in the irradiation dose region up to 100 dpa. The experimental results show that he radiation swelling peak for the modified stainless steel appears in the temperature region around 580 ℃ and the radiation damage is more sensitive to the temperature, the size of the radiation induced vacancy cluster or void increase with the increasing of the irradiation dose, and among the three materials the home-made modified stainless steel has the best radiation resistant property. (authors)

  4. Role of noble metal nanoparticles in DNA base damage and catalysis: a radiation chemical investigation

    International Nuclear Information System (INIS)

    Sharma, Geeta K.

    2011-01-01

    In the emerging field of nanoscience and nanotechnology, tremendous focus has been made by researcher to explore the applications of nanomaterials for human welfare by converting the findings into technology. Some of the examples have been the use of nanoparticles in the field of opto-electronic, fuel cells, medicine and catalysis. These wide applications and significance lies in the fact that nanoparticles possess unique physical and chemical properties very different from their bulk precursors. Numerous methods for the synthesis of noble nanoparticles with tunable shape and size have been reported in literature. The goal of our group is to use different methods of synthesis of noble metal nanoparticles (Au, Ag, Pt and Pd) and test their protective/damaging role towards DNA base damage induced by ionizing radiation (Au and Ag) and to test the catalytic activity of nanoparticles (Pt and Pd) in certain known organic synthesis/electron transfer reactions. Using radiation chemical techniques such as pulse radiolysis and steady state radiolysis complemented by the product analysis using HPLC/LC-MS, a detailed mechanism for the formation of transient species, kinetics leading to the formation of stable end products is studied in the DNA base damage induced by ionizing radiation in presence and absence of Au and Ag nanoparticles. Unraveling the complex interaction between catalysts and reactants under operando conditions is a key step towards gaining fundamental insight in catalysis. The catalytic activity of Pt and Pd nanoparticles in electron transfer and Suzuki coupling reactions has been determined. Investigations are currently underway to gain insight into the interaction between catalysts and reactants using time resolved spectroscopic measurements. These studies will be detailed during the presentation. (author)

  5. Structural and Optical Investigations of Radiation Damage in Transparent PET Polymer Films

    Directory of Open Access Journals (Sweden)

    Shiv Govind Prasad

    2011-01-01

    Full Text Available Effects of gamma irradiation at different doses up to 135 kGy on polyethylene terephthalate (PET polymer films have been investigated by X-ray diffraction (XRD, Fourier transform infrared (FTIR spectroscopy, and ultraviolet-visible (UV-VIS spectroscopy. From XRD analysis, it was found that even at a high dose of gamma irradiation of 135 kGy, crystallinity of the PET samples remain unchanged. However, the FTIR peak at 871 cm−1 (depicting C–H bending mode of out-of-plane vibration and another at 1303 cm−1 (representing C–H bending mode of in-plane vibration disappear for gamma-irradiated PET. In this study, it has also been found that γ-irradiation in air enhances the optical absorption in the wavelength region 320–370 nm. This has been attributed to free radicals being produced in the polymer by the γ-radiation. Further, the free radicals react with oxygen of air to form carbonyl group and hydroxyls. With increasing γ-dose, there is a red shift of the UV—near visible cutoff for PET. XRD and FTIR observations on γ-damage have been correlated.

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

    International Nuclear Information System (INIS)

    Boistel, Renaud; Pollet, Nicolas; Tinevez, Jean-Yves; Cloetens, Peter; Schlenker, Michel

    2009-01-01

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

  7. Radiation damage of uranium

    International Nuclear Information System (INIS)

    Lazarevic, Dj.

    1966-11-01

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

  8. Investigation of the radiation-damage stability of CdS and CdSe crystals by bound excitons spectra

    International Nuclear Information System (INIS)

    Batyrev, A.S.; Novikov, B.V.; Sum'yanova, E.V.; Cherednichenko, A.E.

    1992-01-01

    The bound excitons emission spectra at T=4.2 K are studied in CdS and CsSe single crystals subjected in situ to the keV-electron irradiation. According to the spectra mode, the investigated samples are classified into two groups. The II-group crystals, whose specific feature is the presence in the emission spectra of the so-called I 1 -line, are shown to be more tolerant to radiation damages in comparison with the I-group crystals. The explanation of this effect is given

  9. Radiation damage in DNA

    International Nuclear Information System (INIS)

    Lafleur, V.

    1978-01-01

    A number of experiments are described with the purpose to obtain a better insight in the chemical nature and the biological significance of radiation-induced damage in DNA, with some emphasis on the significance of alkali-labile sites. It is shown that not only reactions of OH radicals but also of H radicals introduce breaks and other inactivating damage in single-standed phiX174 DNA. It is found that phosphate buffer is very suitable for the study of the reactions of H radicals with DNA, as the H 2 PO 4 - ions convert the hydrated electrons into H radicals. The hydrated electron, which does react with DNA, does not cause a detectable inactivation. (Auth.)

  10. Radiation damage in graphite

    CERN Document Server

    Simmons, John Harry Walrond

    1965-01-01

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

  11. Radiation damage to histones

    International Nuclear Information System (INIS)

    Mee, L.K.; Adelstein, S.J.

    1985-01-01

    The damage to histones irradiated in isolation is being elaborated to aid the identification of the crosslinking sites in radiation-induced DNA-histone adducts. Histones are being examined by amino acid analysis to determine the destruction of residues and by polyacrylamide gel electrophoresis to delineate changes in conformation. For the slightly lysine-rich histone, H2A, a specific attack on selective residues has been established, the aromatic residues, tyrosine and phenylalanine, and the heterocyclic residue, histidine, being significantly destroyed. In addition, a significant increase in aspartic acid was found; this may represent a radiation product from scission of the ring in the histidine residues. The similarity of the effects on residues in nitrous oxide-saturated and nitrogen-saturated solutions suggests that OH . and e/sub aq//sup -/ are equally efficient and selective in their attack. On gel electrophoresis degradation of the histone H2A was found to be greatest for irradiations in nitrous oxide-saturated solutions, suggesting CH . is the most effective radical for producing changes in conformation; O/sub 2//sup -/ was essentially ineffective. Other histones are being examined for changes in amino acid composition, conformation, and for the formation of radiation products

  12. Investigation on the effect of developed product and new food for radiation-induced skin damage

    International Nuclear Information System (INIS)

    Kim, Sung Ho; Kim, Jong Chun; Bae, Chun Sik; Kim, Se Ra; Lee, Hae Jun; Bang, Dae Won; Lee, Jin Hee; Kim, Joong Sun; Ki, Sun Ah; Song, Myung Seop

    2007-07-01

    In vivo evaluation of the developed pilot product on the skin protection against UV irradiation and screening of new candidate materials. Project Results are Establishment of experimental methods for 3 morphological indices of UV-induced skin damages -Establishment of experimental methods for whitening effect evaluation -Evaluation of HemoHIM administration on the skin damage indices -Evaluation of HemoHIM skin application on the skin damage indices -Evaluation of HemoTonic administration on the skin damage indices -Evaluation of HemoTonic skin application on the skin damage indices -Evaluation of HemoHIM on the antiinflamatory effects in the inflammation stage 1 -Evaluation of HemoHIM on the antiinflamatory effects in the inflammation stage 2 -Evaluation of HemoHIM on the antiinflamatory effects in the inflammation stage 3 -Evaluation of HemoHIM on the antiinflamatory effects in the TNBS-induced colitis -Evaluation of HemoHIM on the anti-wrinkle effects in the skin -Evaluation of HemoHIM on the protective effects on the skin tissue (epidermal thickening, dermal cellularity, dermal cyst) -Evaluation of HemoHIM on the protective effects on the skin tumor development

  13. Investigation on the effect of developed product and new food for radiation-induced skin damage

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Ho; Kim, Jong Chun; Bae, Chun Sik; Kim, Se Ra; Lee, Hae Jun; Bang, Dae Won; Lee, Jin Hee; Kim, Joong Sun; Ki, Sun Ah; Song, Myung Seop [Chonnam National University, Gwangju (Korea, Republic of)

    2007-07-15

    In vivo evaluation of the developed pilot product on the skin protection against UV irradiation and screening of new candidate materials. Project Results are Establishment of experimental methods for 3 morphological indices of UV-induced skin damages -Establishment of experimental methods for whitening effect evaluation -Evaluation of HemoHIM administration on the skin damage indices -Evaluation of HemoHIM skin application on the skin damage indices -Evaluation of HemoTonic administration on the skin damage indices -Evaluation of HemoTonic skin application on the skin damage indices -Evaluation of HemoHIM on the antiinflamatory effects in the inflammation stage 1 -Evaluation of HemoHIM on the antiinflamatory effects in the inflammation stage 2 -Evaluation of HemoHIM on the antiinflamatory effects in the inflammation stage 3 -Evaluation of HemoHIM on the antiinflamatory effects in the TNBS-induced colitis -Evaluation of HemoHIM on the anti-wrinkle effects in the skin -Evaluation of HemoHIM on the protective effects on the skin tissue (epidermal thickening, dermal cellularity, dermal cyst) -Evaluation of HemoHIM on the protective effects on the skin tumor development

  14. Investigation of damage to metals by pulsed CO2 laser radiation

    Science.gov (United States)

    Vedenov, A. A.; Gladush, G. G.; Drobyazko, S. V.; Senatorov, Yu M.

    1981-10-01

    A study was made of the physical mechanism involved in piercing holes in metallic plates, using CO2 laser radiation. It was established experimentally that the energy consumed in removing a unit volume of a metal has a minimum, depending on the duration and energy of the laser pulse. An explanation is proposed for the laws governing this behavior, based on ideas of the ejection of liquid from a crater by the vapor pressure of the material. The effect on the interaction efficiency of the absorption of laser radiation in the plasma jet is taken into account.

  15. An EPR investigation of room temperature radiation damage and molecular motion in the ferroelectric phosphates

    International Nuclear Information System (INIS)

    Dalal, N.S.; Herak, J.N.; McDowell, C.A.

    1976-01-01

    Several types of paramagnetic centers have been detected in the room temperature irradiated KH 2 PO 4 , KD 2 PO 4 , KH 2 PO 4 -KH 2 AsO 4 , KD 2 PO 4 -KD 2 AsO 4 and in the newly discovered ferroelectric NaTh 2 (PO 4 ) 3 . Comparative studies of temperature dependence in the EPR spectra show that as in KH 2 PO 4 -type crystals, the ferroelectric phase transition in NaTh 2 (PO 4 ) 3 crystals also seems to be related to the motion of the PO 4 units. The results help to clarify some earlier observed anomalies on the effects of γ-irradiation on dielectric properties of KH 2 PO 4 and in particular, show that the extent of the damage can be controlled by changing the impurity content of the unirradiated samples. (Auth.)

  16. Investigation of the radiation damage of GaAs detectors by neutrons and photons

    Science.gov (United States)

    Braunschweig, W.; Kubicki, Th.; Lübelsmeyer, K.; Pandoulas, D.; Syben, O.; Tenbusch, F.; Toporowsky, M.; Wilms, Th.; Wittmer, B.; Xiao, W. J.

    1996-02-01

    Surface barrier particle detectors, processed in Aachen using SI GaAs from several manufacturers, have been irradiated with neutrons (peak energy ˜1 MeV) up to fluences of 4.0 × 10 14 n/cm 2 and with photons from a 60Co source with a dose of 100 Mrad. All detectors work well after the irradiation. Detectors biased with 200 V during the neutron irradiation show no significant difference from those not biased. After irradiation with 4.0 × 10 14 n/cm 2 the leakage currents at 200 V are a factor of 4 greater than those before irradiation. At the highest radiation level the signal for minimum ionizing particles corresponds to 7200 electrons (at 200 V bias voltage) independent of peaking times between 40 ns and 2.2 μs. The signals for α-particles (2.2 μs peaking time, 200 V bias voltage) are about 20% of those before irradiation. The exposure to the 100 Mrad photon dose caused little change of the detector performance. The leakage currents were even reduced by about 10%.

  17. Spectroscopic properties and radiation damage investigation of a diamond based Schottky diode for ion-beam therapy microdosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Verona, C.; Marinelli, Marco; Verona-Rinati, G. [INFN - Dipartimento di Ingegneria Industriale, Università di Roma “Tor Vergata,” Roma (Italy); Magrin, G.; Solevi, P.; Mayer, R. [EBG MedAustron Marie Curie-St. 5, 2700 Wiener Neustadt (Austria); Grilj, V.; Jakšić, M. [Ruder Boškovic Institute, Bijenicka cesta 54, P.O. Box 180, 10002 Zagreb (Croatia)

    2015-11-14

    In this work, a detailed analysis of the properties of a novel microdosimeter based on a synthetic single crystal diamond is reported. Focused ion microbeams were used to investigate the device spectropscopic properties as well as the induced radiation damage effects. A diamond based Schottky diode was fabricated by chemical vapor deposition with a very thin detecting region, about 400 nm thick (approximately 1.4 μm water equivalent thickness), corresponding to the typical size in microdosimetric measurements. A 200 × 200 μm{sup 2} square metallic contact was patterned on the diamond surface by standard photolithography to define the sensitive area. Experimental measurements were carried out at the Ruder Boškovic′ Institute microbeam facility using 4 MeV carbon and 5 MeV silicon ions. Ion beam induced charge maps were employed to characterize the microdosimeter response in terms of its charge collection properties. A stable response with no evidence of polarization or memory effects was observed up to the maximum investigated ion beam flux of about 1.7 × 10{sup 9} ions·cm{sup −2}·s{sup −1}. A homogeneity of the response about 6% was found over the sensitive region with a well-defined confinement of the response within the active area. Tests of the radiation damage effect were performed by selectively irradiating small areas of the device with different ion fluences, up to about 10{sup 12} ions/cm{sup 2}. An exponential decrease of the charge collection efficiency was observed with a characteristic decay constant of about 4.8 MGy and 1 MGy for C and Si ions, respectively. The experimental data were analyzed by means of GEANT4 Monte Carlo simulations. A direct correlation between the diamond damaging effect and the Non Ionizing Energy Loss (NIEL) fraction was found. In particular, an exponential decay of the charge collection efficiency with an exponential decay as a function of NIEL is observed, with a characteristic constant of about

  18. Radiation damage in silicon detectors

    CERN Document Server

    Bruzzi, Mara

    2000-01-01

    This work presents an overview of the most important mechanisms of radiation damage in silicon detectors to be used for high energy experiments in LHC. The changes in the shallow concentration have been studied by Thermally Stimulated Currents (TSC) after proton and neutron irradiation with fluences up to 1015 cm-2 to investigate the role of thermal donors and the donor-removal effect in standard and oxygen enriched silicon with different resistivities. Deep defects in irradiated silicon have been analysed by Deep Level Transient Spectroscopy (DLTS) and Photo Induced Current Transient Spectroscopy (P1CTS) in the same materials. The radiation-induced microscopic disorder has been related with the carrier transport properties of irradiated silicon measured by Hall effect, by capacitance and current vs. voltage characteristics and with charge collection efficiency. The dependence of the irradiated silicon detectors performances on crystal orientation, on incident particle type and on the starting concentration o...

  19. Investigation of the radiation damage of GaAs detectors by protons, pions and neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Luebelsmeyer, K. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Arbabi, S. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Braunschweig, W. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Chu, Z. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Krais, R. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Kubicki, T. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Rente, C. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Syben, O. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Tenbusch, F. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Toporowski, M. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Wittmer, B. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Xiao, W.J. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.

    1997-05-01

    Surface barrier detectors processed in Aachen using semi-insulating (SI) GaAs from several manufacturers have been irradiated with high fluences of neutrons (mean energy 1 MeV, fluence up to {Phi}{sub n} {proportional_to} 5 x 10{sup 14} cm{sup -2}), pions (191 MeV, fluence up to {Phi}{sub {pi}} {proportional_to} 0.6 x 10{sup 14} cm{sup -2}) and protons (23 GeV, fluence up to {Phi}{sub p} {proportional_to} 2 x 10{sup 14} cm{sup -2}). The detectors have been characterized in terms of macroscopic quantities like I-V characteristic curves and charge collection efficiencies for incident minimum ionizing- (mip) as well as {alpha}-particles. All detectors work well after the exposure. At the highest fluences a sizable degradation in the charge collection efficiencies has been observed for all investigated materials. SI-GaAs material with low carbon (LC) content seems to be less affected than substrates with a higher carbon concentration. At the highest irradiation level the mip signal from a 250 {mu}m thick detector made of LC material amounts to 8000 electrons (at 400 V bias voltage) independent of peaking times between 40 ns and 2.2 {mu}s. The leakage currents for this material are even reduced after the irradiation. (orig.).

  20. Investigation of the radiation damage of GaAs detectors by protons, pions and neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Tenbusch, F. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Arbabi, S. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Braunschweig, W. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Chu, Z. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Krais, R. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Kubicki, T. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Luebelsmeyer, K. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Rente, C. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Syben, O. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Toporowski, M. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Wittmer, B. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Xiao, W.J. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.

    1997-04-01

    Surface barrier detectors processed in Aachen using SI-GaAs from several manufacturers have been irradiated with high fluences of neutrons (mean energy 1 MeV, fluence up to {Phi}{sub n}{proportional_to}5 x 10{sup 14} cm{sup -2}), pions (191 MeV, fluence up to {Phi}{sub {pi}}{proportional_to}0.6 x 10{sup 14} cm{sup -2}) and protons (23 GeV, fluence up to {Phi}{sub p}{proportional_to}2 x 10{sup 14} cm{sup -2}). The detectors have been characterized in terms of macroscopic quantities like I-V characteristic curves and charge collection efficiencies for incident minimum ionizing- (mip) as well as {alpha}-particles. All detectors work well after the exposure. At the highest fluences a sizable degradation concerning the charge collection efficiencies has been observed for all investigated materials. SI-GaAs material with low carbon content (LC material from FCM, Freiberg) seems to be less affected than substrates with a higher carbon concentration. At the highest irradiation level the mip signal from a 250 {mu}m thick detector made of LC material amounts to 8000 electrons (at 400 V bias voltage) independent of peaking times between 40 ns and 2.2 {mu}s. The leakage currents for this material are even reduced after the irradiation. (orig.).

  1. Edge-TCT for the investigation of radiation damaged silicon strip sensors

    International Nuclear Information System (INIS)

    Feindt, Finn

    2017-02-01

    The edge Transient Current Technique (TCT) is a method for the investigation of silicon sensors. This method requires infrared light from a sub-ns pulsed laser to be focused to a μm-size spot and scanned across the polished cut edge of a sensor. Electron-hole pairs are generated along the light beam in the sensor. These charge carriers drift in the electric field and induce transient currents on the sensor electrodes. The current transients are analyzed as a function of the applied voltage, temperature, absorbed dose and position of the laser-light focus, in order to determine the the drift velocities, electric field and the charge collection in the strip sensor. In the scope of this work, a new edge-TCT setup is commissioned, a procedure for the polishing of the cut edge is implemented and a method to position the focus of the laser light with respect to the sensor is developed. First edge-TCT measurements are performed on non-irradiated, 285 μm thick n-type strip sensors, and the pulse shape and charge collection is studied under different conditions. Furthermore, the prompt current of the transients is extracted, which is the first step towards the determination of the electric field. A new method to measure the attenuation of light in silicon is tested on a non-irradiated sensor and on sensors irradiated with up to a 1 MeV neutron equivalent fluence of 1.14 x 10 15 cm -2 , using laser light with a wavelength of 1052 nm.

  2. Radiation Damage of Quartz Fibers

    OpenAIRE

    Hagopian, V

    1999-01-01

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

  3. Radiation damage in biomolecular systems

    CERN Document Server

    Fuss, Martina Christina

    2012-01-01

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

  4. Radiation damage in plastic detectors

    International Nuclear Information System (INIS)

    Balcazar, M.; Tavera, L.

    2007-01-01

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

  5. Radiation damages in superconducting materials

    International Nuclear Information System (INIS)

    Heinz, W.; Seibt, E.

    1978-01-01

    Radiation damage investigations of technical superconductors are reported and discussed with respect to their main properties like critical current jsub(c), transition temperature Tsub(c), upper critical field Bsub(c2), pinning and annealing behaviour. Ordered A15 type alloys (like Nb 3 Sn and V 3 Ga) show significant reductions of all critical parameters above a threshold of about 2x10 21 m -2 with 50 MeV deuterons corresponding to 2x10 22 neutrons/m 2 (Esub(n)>0.1 MeV). Pure metals and disordered B1 type alloys (like Nb or NbTi) show only a small linear decrease in critical parameters (except Bsub(c2) of niobium). Experimental results are compared with theoretical calculations. (author)

  6. Nuclear Radiation Damages Minds!

    Science.gov (United States)

    Blai, Boris, Jr.

    Professors Ernest Sternglass (University of Pittsburgh) and Steven Bell (Berry College) have assembled cogent, conclusive evidence indicating that nuclear radiation is associated with impaired cognition. They suggest that Scholastic Aptitude Scores (SATs), which have declined steadily for 19 years, will begin to rise. Their prediction is based on…

  7. Radiation damage considerations

    International Nuclear Information System (INIS)

    Frost, B.R.T.

    1975-08-01

    The designs of nuclear fission and fusion power plants do not, in general, appear to make unusual demands on materials in terms of mechanical-property requirements. Radiation environments produce unique effects on the composition, microstructure, and defect population of these alloys, resulting in time-dependent and time-independent changes in mechanical properties. To illustrate these problems, the materials needs of the core of a Liquid-Metal Fast-Breeder Reactor (LMFBR) and of the first wall of a fusion reactor are discussed. In the case of the LMFBR core, the phenomenon of void swelling causes serious design problems, and a search is being made for a low-swelling alloy that has adequate mechanical properties. The fusion reactor poses different problems because the neutron energy is high (14 MeV) and is accompanied by a high flux of charged particles. The long-term choices for a wall material have been narrowed to vanadium and niobium alloys. In the search for low-swelling alloys, it has become clear that minor elements play an important role in determining the nature of the radiation effects. The segregation of minor elements to void surfaces and the dispersion and reformation of second-phase precipitates are two important radiation-induced phenomena that require additional study in view of their influence on void swelling and high-temperature properties

  8. Radiation-induced liver damage

    International Nuclear Information System (INIS)

    Marcial, V.A.; Santiago-Delpin, E.A.; Lanaro, A.E.; Castro-Vita, H.; Arroyo, G.; Moscol, J.A.; Gomez, C.; Velazquez, J.; Prado, K.

    1977-01-01

    Due to the recent increase in the use of radiation therapy in the treatment of cancer with or without chemotherapy, the risk of liver radiation damage has become a significant concern for the radiotherapist when the treated tumour is located in the upper abdomen or lower thorax. Clinically evident radiation liver damage may result in significant mortality, but at times patients recover without sequelae. The dose of 3000 rads in 3 weeks to the entire liver with 5 fractions per week of 200 rads each, seems to be tolerated well clinically by adult humans. Lower doses may lead to damage when used in children, when chemotherapy is added, as in recent hepatectomy cases, and in the presence of pre-existent liver damage. Reduced fractionation may lead to increased damage. Increased fractionation, limitation of the dose delivered to the entire liver, and restriction of the high dose irradiation volume may afford protection. With the aim of studying the problems of hepatic radiation injury in humans, a project of liver irradiation in the dog is being conducted. Mongrel dogs are being conditioned, submitted to pre-irradiation studies (haemogram, blood chemistry, liver scan and biopsy), irradiated under conditions resembling human cancer therapy, and submitted to post-irradiation evaluation of the liver. Twenty-two dogs have been entered in the study but only four qualify for the evaluation of all the study parameters. It has been found that dogs are susceptible to liver irradiation damage similar to humans. The initial mortality has been high mainly due to non-radiation factors which are being kept under control at the present phase of the study. After the initial experiences, the study will involve variations in total dose and fractionation, and the addition of anticoagulant therapy for possible prevention of radiation liver injury. (author)

  9. Symmetry preservation during radiation damage

    International Nuclear Information System (INIS)

    Bhat, S.V.; Abdel-Gawad, M.M.H.

    1991-01-01

    An examination of radiation-damage processes consequent to high-energy irradiation in certain ammonium salts studied using ESR of free radicals together with the structural information available from neutron diffraction studies shows that, other factors being equal/nearly equal, symmetry-related bonds are preserved in preference to those unrelated to one another by any symmetry. (author). 23 refs., 3 tabs

  10. Mechanisms for radiation damage in DNA

    International Nuclear Information System (INIS)

    Sevilla, M.D.

    1993-12-01

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

  11. A tan in a test tube - in vitro models for investigating ultraviolet radiation-induced damage in skin.

    Science.gov (United States)

    Fernandez, Tara L; Dawson, Rebecca A; Van Lonkhuyzen, Derek R; Kimlin, Michael G; Upton, Zee

    2012-06-01

    Presently, global rates of skin cancers induced by ultraviolet radiation (UVR) exposure are on the rise. In view of this, current knowledge gaps in the biology of photocarcinogenesis and skin cancer progression urgently need to be addressed. One factor that has limited skin cancer research has been the need for a reproducible and physiologically-relevant model able to represent the complexity of human skin. This review outlines the main currently-used in vitro models of UVR-induced skin damage. This includes the use of conventional two-dimensional cell culture techniques and the major animal models that have been employed in photobiology and photocarcinogenesis research. Additionally, the progression towards the use of cultured skin explants and tissue-engineered skin constructs, and their utility as models of native skin's responses to UVR are described. The inherent advantages and disadvantages of these in vitro systems are also discussed. © 2012 John Wiley & Sons A/S.

  12. Mechanisms for radiation damage in DNA

    International Nuclear Information System (INIS)

    Sevilla, M.D.

    1987-01-01

    Several mechanisms are proposed for radiation damage to DNA and its constituents, and a series of experiments utilizing electron spin resonance spectrometry have been used to test the proposed mechanisms. In the past we have concentrated chiefly on investigating irradiated systems of DNA constituents. In this year's effort we have concentrated on radiation effects on DNA itself. In addition studies of radiation effects on lipids and model compounds have been performed which shed light on the only other proposed site for cell kill, the membrane

  13. Undulator Radiation Damage Experience at LCLS

    International Nuclear Information System (INIS)

    Nuhn, H. D.; Field, C.; Mao, S.; Levashov, Y.; Santana, M.; Welch, J. N.; Wolf, Z.

    2015-01-01

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

  14. Radiation damage of structural materials

    CERN Document Server

    Koutsky, Jaroslav

    1994-01-01

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

  15. The study of radiation damage of EPROM 2764 memory

    Directory of Open Access Journals (Sweden)

    Domanski Grzegorz

    2016-01-01

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

  16. Radiation, DNA damage and cancer

    International Nuclear Information System (INIS)

    Hall, J.; Angele, S.

    1999-01-01

    The characterization of the rare, radiation-sensitive and cancer-prone syndromes, ataxia telangiectasia and Nijmegen breakage syndrome, has demonstrated that genetic predisposition increases the risk of developing cancer after exposure to ionizing radiation (IR). Molecular analyses of these disorders provide valuable insights into the normal function of these two gene products in the cellular response to IR-induced DNA damage. Their contribution to a cellular radiosensitive phenotype and their role in sporadic cancers can now be fully assessed. For example, the gene ataxia telangiectasia mutated (Atm) has recently been shown to be a tumour suppressor gene in T-cell pro lymphocytic leukaemia, and there is increasing evidence that individuals with one mutated Atm or Nijmegen breakage syndrome (Nbs) allele have an increased predisposition to cancer. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  17. Radiation, DNA damage and cancer

    Energy Technology Data Exchange (ETDEWEB)

    Hall, J.; Angele, S. [Unit of Mechanisms of Carcinogenesis, International Agency for Research on Cancer, 150 cours Albert Thomas, 69372 Lyon (France)

    1999-04-01

    The characterization of the rare, radiation-sensitive and cancer-prone syndromes, ataxia telangiectasia and Nijmegen breakage syndrome, has demonstrated that genetic predisposition increases the risk of developing cancer after exposure to ionizing radiation (IR). Molecular analyses of these disorders provide valuable insights into the normal function of these two gene products in the cellular response to IR-induced DNA damage. Their contribution to a cellular radiosensitive phenotype and their role in sporadic cancers can now be fully assessed. For example, the gene ataxia telangiectasia mutated (Atm) has recently been shown to be a tumour suppressor gene in T-cell pro lymphocytic leukaemia, and there is increasing evidence that individuals with one mutated Atm or Nijmegen breakage syndrome (Nbs) allele have an increased predisposition to cancer. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  18. Radiation damage to DNA constituents

    International Nuclear Information System (INIS)

    Bergene, R.

    1977-01-01

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

  19. Health effects of radiation damage

    International Nuclear Information System (INIS)

    Gasimova, K; Azizova, F; Mehdieva, K.

    2012-01-01

    Full text : A summary of the nature of radiactive contamination would be incomplete without some mention of the human health effects relatied to radioactivity and radioactive materials. Several excellent reviews at the variety of levels of detail have been written and should be consulted by the reader. Internal exposures of alpha and beta particles are important for ingested and inhaled radionuclides. Dosimetry models are used to estimate the dose from internally deposited radioactive particles. As mentioned above weighting parameters that take into account the radiation type, the biological half-life and the tissue or organ at risk are used to convert the physically absorbed dose in units of gray (or red) to the biologically significant committed equivalent dose and effective dose, measured in units of Sv (or rem). There is considerable controversy over the shape of the dose-response curve at the chronic low dose levels important for enviromental contamination. Proposed models include linear models, non-linear models and threshold models. Because risks at low dose must be extrapolated from available date at high doses, the shape of the dose-response curve has important implications for the environmental regulations used to protect the general public. The health effect of radiation damage depends on a combination of events of on the cellular, tissue and systemic levels. These lead to mutations and cellular of the irradiated parent cell. The dose level at which significant damage occurs depends on the cell type. Cells that reproduce rapidily, such as those found in bone marrow or the gastrointestinal tract, will be more sensitive to radiation than those that are longer lived, such as striated muscle or nerve cells. The effects of high radiation doses on an organ depends on the various cell types it contains

  20. Studies on the Neutron Radiation Damage Equivalence

    Directory of Open Access Journals (Sweden)

    ZOU De-hui

    2015-01-01

    Full Text Available To establish a unified standard of the evaluation of different sources of radiation damage, the neutron radiation damage equivalent standard source was determined both at home and abroad, and a lot of equivalence research work was done for making weapons anti neutron radiation performance examination and acceptance basis. The theoretical research progress was combed according to the relationship between the displacement damage function and the radiation source spectra ,and the experimental research progress was combed from the basic experimental methods, the controlling trend of effect parameters and field parameters. The experiment method to reduce the uncertainty was discussed, and present the research directions of radiation damage equivalence.

  1. Radiation damage in nanostructured metallic films

    Science.gov (United States)

    Yu, Kaiyuan

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

  2. Study of radiation damage to the CMS Hadronic Endcap Calorimeter and investigation into new physics using multi-boson measurements

    Energy Technology Data Exchange (ETDEWEB)

    Belloni, Alberto [Univ. of Maryland, College Park, MD (United States)

    2016-03-31

    This document is the final report for the U.S. D.O.E. Grant No. DE-SC0014088, which covers the period from May 15, 2015 to March 31, 2016. The funded research covered the study of multi-boson final states, culminated in the measurement of the W±γγ and, for the first time at an hadronic collider, of the Zγγ production cross sections. These processes, among the rarest multi-boson final states measurable by LHC experiments, allow us to investigate the possibility of new physics in a model-independent way, by looking for anomalies in the standard model couplings among electroweak bosons. In particular, these 3-boson final states access quartic gauge couplings; the W±γγ analysis performed as a part of this proposal sets limits on anomalies in the WWγγ quartic gauge coupling. The award also covered R&D activities to define a radiation-tolerant material to be used in the incoming upgrade of the CMS hadronic endcap calorimeter. In particular, the usage of a liquid-scintillator-based detector was investigated. The research work performed in this direction has been collected in a paper recently submitted for publication in the Journal of Instrumentation (JINST).

  3. Radiation damages in solids and tissues

    International Nuclear Information System (INIS)

    Cevc, P.; Kogovsek, F.; Kanduser, A.; Peternelj, M.; Skaleric, U.; Funduk, N.

    1977-01-01

    In submitted research work we have studied radiation damages in ferroelectric crystals and application of ferroelectric crystals. Studying the radiation damages we have introduced new technique of EPR measurements under high hydrostatic pressure, that will enable us to obtain additional data on crystal lattice dynamics. A change of piroelectric coefficient with high radiation doses in dopped TGS has been measured also

  4. Radiation-induced damage of membranes

    International Nuclear Information System (INIS)

    Yonei, Shuji

    1977-01-01

    An outline of membranous structure was stated, and radiation-induced damage of membranes were surveyed. By irradiation, permeability of membranes, especially passive transportation mechanism, was damaged, and glycoprotein in the surface layers of cells and the surface layer structures were changed. The intramembranous damage was induced by decrease of electrophoresis of nuclear mambranes and a quantitative change of cytochrome P450 of microsomal membranes of the liver, and peroxidation of membranous lipid and SH substitute damage of membranous protein were mentioned as the mechanism of membranous damage. Recovery of membranous damage depends on radiation dose and temperature, and membranous damage participates largely in proliferation death. (tsunoda, M.)

  5. Simulation of radiation damage in zircon

    Energy Technology Data Exchange (ETDEWEB)

    Weber, W.J.; Maupin, G.D.

    1988-05-01

    Radiation damage in natural zircon minerals due to alpha decay over geologic time has been simulated in laboratory studies extending over 5.5 years using Pu-doped synthetic zircon. These studies confirm for the first time that laboratory testing of actinide-doped materials can accurately predict the radiation-damage behavior of radioactive waste forms over geologic time and also provide new insights into interpretation of radiation damage in natural minerals.

  6. Simulation of radiation damage in zircon

    Energy Technology Data Exchange (ETDEWEB)

    Weber, W.J.; Maupin, G.D.

    1987-06-01

    Radiation damage in natural zircon minerals due to alpha decay has been simulated in laboratory studies using Pu-doped synthetic zircon. These studies confirm that laboratory testing of actinide-doped materials can accurately predict the radiation-damage behavior of radioactive waste forms over geologic time, and also provide new insights into interpretation of radiation damage in natural minerals. 15 refs., 4 figs., 2 tabs.

  7. Radiation damage at LHCb, results and expectations

    CERN Multimedia

    Faerber, Christian

    2011-01-01

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

  8. Repair of radiation damage in mammalian cells

    International Nuclear Information System (INIS)

    Setlow, R.B.

    1981-01-01

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

  9. Metamict state radiation damage in crystalline materials

    International Nuclear Information System (INIS)

    Haaker, R.F.; Ewing, R.C.

    1979-01-01

    Metamict minerals provide an excellent basis for the evaluation of long-term radiation damage effects, particularly such changes in physical and chemical properties as microfracturing, hydrothermal alteration, and solubility. This paper summarizes pertinent literature on metamictization and proposes experiments that are critical to the elucidation of structural controls on radiation damage in crystalline phases

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

    Science.gov (United States)

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

    2012-08-01

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

  11. Ion - biomolecule interactions and radiation damage

    International Nuclear Information System (INIS)

    Schlathoelter, T.

    2004-01-01

    Full text: The biological effects of ionizing radiation in living cells are not a mere result of the direct impact of high energy quanta of radiation. Secondary particles such as low energy electrons, radicals and (multiply charged) ions are formed within the track. The interaction of these secondary particles with biologically relevant molecules is responsible for a large fraction of biological radiation damage to a cell, as well. Singly and multiply charged ions can be of importance as both, primary and secondary particles, and are known to cause severe biological damage. For instance, in heavy ion therapy and proton therapy the pronounced Bragg peak of fast (typically a few 100 MeV/u) ions in biological tissue is utilized. The Bragg peak is located at a depth, where the ions (mostly C q+ or protons) are slowed down to about 100 keV/u and have their maximum linear energy transfer (LET) to the medium. This depth is reasonably well defined and depends on the initial ion kinetic energy. Since the ions are rapidly stopped in this energy range, penetration beyond the Bragg peak is weak and it is thus possible to 'scan' the Bragg peak through a malignant tumour without excessive damage of the surrounding tissue by mere variation of the ion kinetic energy (i.e. the penetration depth). Severe biological damage is almost only possible, when the track of a primary quantum of ionizing radiation crosses the nucleus of a cell. Particularly the induction of double strand breaks of DNA or clustered DNA lesions is potentially lethal or mutagenic. A primary particle interacting with individual molecules within this environment leads to molecular excitation, ionization and fragmentation. In the process, the primary particle looses energy and slow secondary electrons and ions are formed, which might induce further damage. For a deep understanding of biological radiation damage on the level of individual molecules it is thus important to quantify excitation, ionization and

  12. Thermal annealing of natural, radiation-damaged pyrochlore

    Energy Technology Data Exchange (ETDEWEB)

    Zietlow, Peter; Beirau, Tobias; Mihailova, Boriana; Groat, Lee A.; Chudy, Thomas; Shelyug, Anna; Navrotsky, Alexandra; Ewing, Rodney C.; Schlüter, Jochen; Škoda, Radek; Bismayer, Ulrich

    2017-01-01

    Abstract

    Radiation damage in minerals is caused by the α-decay of incorporated radionuclides, such as U and Th and their decay products. The effect of thermal annealing (400–1000 K) on radiation-damaged pyrochlores has been investigated by Raman scattering, X-ray powder diffraction (XRD), and combined differential scanning calorimetry/thermogravimetry (DSC/TG). The analysis of three natural radiation-damaged pyrochlore samples from Miass/Russia [6.4 wt% Th, 23.1·10

  13. Radiation damage in barium fluoride detector materials

    International Nuclear Information System (INIS)

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

    1988-01-01

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

  14. Radiation damage to nucleoprotein complexes in macromolecular crystallography

    International Nuclear Information System (INIS)

    Bury, Charles; Garman, Elspeth F.; Ginn, Helen Mary; Ravelli, Raimond B. G.; Carmichael, Ian; Kneale, Geoff; McGeehan, John E.

    2015-01-01

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

  15. DNA Damage Signals and Space Radiation Risk

    Science.gov (United States)

    Cucinotta, Francis A.

    2011-01-01

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

  16. Investigation of Combined Action of Food Supplement's and Ionizing Radiation on the Cytogenetic Damage Induction and Ehrlich Ascite Carcinoma Growth on Mice in Vivo

    Science.gov (United States)

    Sorokina, Svetlana; Zaichkina, Svetlana; Dyukina, Alsu; Rozanova, Olga; Balakin, Vladimir; Peleshko, Vladimir; Romanchenko, Sergey; Smirnova, Helena; Aptikaeva, Gella; Shemyakov, Alexander

    In recent ten years one of the major problems of modern radiobiology is the study of radiation protective mechanisms with the help of different substances as well as activation of internal resources of the organism. Internal resources mean such phenomena as hormesis and adaptive response which represent cell or body reaction on low doses of inducing factors and predetermine their further high dose effect resistance. At present special interest is attracted by studies of biological effects of low-dose-rate high-LET radiation because of searching for new types of radiation for more effective cancer therapy and searching for new methods of radiation protection. Since natural biologically active substances have low toxicity and are capable of affecting physiological processes taking place in human’s organism and increasing organism’s natural defense system, the interest to protective means of vegetal origin and search of special food supplements intensifies every year. The purpose of this study is to investigate the combined influence of food supplement, low dose rate high-LET radiation simulating high-altitude flight conditions and X-ray radiations on radiosensitivity, induction of radiation adaptive response (RAR) and growth of Ehrlich ascite carcinoma as well. Experiments were performed with males of SHK mice at the age of two months. The animals were being irradiated with low-dose-rate high-LET radiation with the dose of 11,6 cGy (0,5 cGy/day) behind the concrete shield of the 70 GeV protons accelerator (Protvino). The X-ray irradiation was carried out on the RTH device with a voltage of 200 kV (1 Gy/min; Pushchino). The diet composition included products containing big amount of biologically active substances, such as: soybeam meat, buckwheat, lettuce leaves and drug of cod-liver oil. Four groups of mice were fed with selected products mentioned above during the whole irradiation period of 22 days. The control groups received the same food without irradiation

  17. Investigating α-particle radiation damage in phyllosilicates using synchrotron microfocus-XRD/XAS: implications for geological disposal of nuclear waste

    Science.gov (United States)

    Bower, W. R.; Pearce, C. I.; Pimblott, S. M.; Haigh, S. J.; Mosselmans, J. F. W.; Pattrick, R. A. D.

    2014-12-01

    The response of mineral phases to the radiation fields that will be experienced in a geological disposal facility (GDF) for nuclear waste is poorly understood. Phyllosilicates are critical phases in a GDF with bentonite clay as the backfill of choice surrounding high level wastes in the engineered barrier, and clays and micas forming the most important reactive component of potential host rocks. It is essential that we understand changes in mineral properties and behaviour as a result of damage from both α and γ radiation over long timescales. Radiation damage has been demonstrated to affect the physical integrity and oxidation state1 of minerals which will also influence their ability to react with radionuclides. Using the University of Manchester's newly commissioned particle accelerator at the Dalton Cumbrian Facility, UK, model phyllosilicate minerals (e.g. biotite, chlorite) were irradiated with high energy (5MeV) alpha particles at controlled dose rates. This has been compared alongside radiation damage found in naturally formed 'radiohalos' - spherical areas of discolouration in minerals surrounding radioactive inclusions, resulting from alpha particle penetration, providing a natural analogue to study lattice damage under long term bombardment1,2. Both natural and artificially irradiated samples have been analysed using microfocus X-ray absorption spectroscopy and high resolution X-ray diffraction mapping on Beamline I18 at Diamond Light Source; samples were probed for redox changes and long/short range disorder. This was combined with lattice scale imaging of damage using HR-TEM (TitanTM Transmission Electron Microscope). The results show aberrations in lattice parameters as a result of irradiation, with multiple damage-induced 'domains' surrounded by amorphous regions. In the naturally damaged samples, neo-formed phyllosilicate phases are shown to be breakdown products of highly damaged regions. A clear reduction of the Fe(III) component has been

  18. Radiation Damage in Electronic Memory Devices

    OpenAIRE

    Fetahović, Irfan; Pejović, Milić; Vujisić, Miloš

    2013-01-01

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

  19. Physics of radiation damage and radiation materials technology

    International Nuclear Information System (INIS)

    1992-01-01

    This issue of 'Problems in Atomic Science and Technology', on the 'Physics of Radiation Damage and Radiation Materials Technology', is a collection of 24 papers on the effects on or processes in materials due to their irradiation by neutrons, ions in the energy range from a few tens of keV to several MeV (deuterium, helium, oxygen), and electrons. Included are studies on radiation damage of materials, on ion implantation, thermonuclear reactor materials testing, fast-particle energy loss ramifications for fusion reaction rates in materials, and biological radiation effects

  20. New concepts for radiation damage

    International Nuclear Information System (INIS)

    Michelin, Severino C.

    2004-01-01

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

  1. Protection of DNA damage by radiation exposure

    International Nuclear Information System (INIS)

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

    1998-12-01

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

  2. Protection of DNA damage by radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-12-01

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

  3. Development of fusion first-wall radiation damage facilities

    International Nuclear Information System (INIS)

    McElroy, R.J.; Atkins, T.

    1986-11-01

    The report describes work performed on the development of fusion-reactor first-wall simulation facilities on the Variable Energy Cyclotron, at Harwell, United Kingdom. Two irradiation facilities have been constructed: i) a device for helium and hydrogen filling up to 1000 ppm for post-irradiation mechanical properties studies, and ii) a helium implantation and damage facility for simultaneous injection of helium and radiation damage into a specimen under stress. These facilities are now fully commissioned and are available for investigations of first-wall radiation damage and for intercorrelation of fission- and fusion -reactor materials behaviour. (U.K.)

  4. Critical behavior in radiation damaged systems

    International Nuclear Information System (INIS)

    Arends, A.R.; Honenemser, C.

    1980-01-01

    Perturbed angular distribution (PAD) measurements of Bleck et al. of the critical behavior of 63 NiNi, 66 CuNi, and 67 ZnNi have been reanalyzed, and shown to be insufficiently asymptotic to permit deduction of meaningful critical exponents. Via experiments on implanted 111 InNi, done with and without annealing of radiation damage, and by comparison to diffused 111 InNi, it is suggested that unannealed radiation damage can produce serious systematic errors in critical exponents. (orig.)

  5. Nanofoams Response to Radiation Damage

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-07-30

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

  6. Mechanisms for radiation damage in DNA

    International Nuclear Information System (INIS)

    Sevilla, M.D.

    1985-07-01

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

  7. Radiation Damage in Electronic Memory Devices

    Directory of Open Access Journals (Sweden)

    Irfan Fetahović

    2013-01-01

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

  8. Radiation induced peroxidative damage: mechanism and significance

    International Nuclear Information System (INIS)

    Agrawal, Anjali; Kale, R.K.

    2001-01-01

    An interest has been generated in free radicals after the discovery of superoxide dismutase. These free radicals cause a number of diseases and are involved in the detrimental effect of ionizing radiation. Efforts have been made to understand their role in damage and death of the cell using lipid peroxidation process. Lipid peroxidation is an important effect of radiation on membranes, which apart from DNA, are critical targets of radiation action. This paper addresses the basic mechanism of radiation induced lipid peroxidation. Various factors, which determine the mode and magnitude of lipid peroxidation, are also discussed. Lipid peroxidation is shown to have importance in understanding the modifications of radiation effects. Efforts are made to show similarities between radiolytic and non-radiolytic lipid peroxidation. Recent findings related to the close link between radiation-induced lipid peroxidation and apoptosis are likely to open new avenues for future research and to develop new approaches for radio modification of biological effects. (author)

  9. Animal Models of Ionizing Radiation Damage

    Science.gov (United States)

    1992-01-01

    irradiated vessels of various tissues (54). Severely damaged blood vessels, those with thrombosis or occlusion, can produce marked changes in tissues...X-irradiation of the Rat, Radiat. Res., 20:471-476, 1963. 153. Persinger, M.A., and T.B. Fiss, Mesenteric Mast Cell Degranulation is not Essential... Thrombosis of the Heart Induced by Radiation, Arch. Path., 96:1-4, 1973. 8. Bruner, A., Immediate Changes in Estimated Cardiac Output and Vascular Resistance

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

    International Nuclear Information System (INIS)

    1963-01-01

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

  11. Radiation damage testing at the SSC [Superconducting Super Collider

    International Nuclear Information System (INIS)

    Chinowsky, W.; Thun, R.

    1990-06-01

    A Task Force on Radiation Damage Testing met at the SSC Laboratory on March 5--6, 1990. This Task Force was asked to assess the availability of appropriate facilities for radiation damage tests of SSC detector materials and components. The Task Force was also instructed to review the techniques and standards for conducting such tests. Semiconductors were considered separately from other detector materials. Radiation damage test of electronic devices generally require exposures to both ionizing radiation and neutrons, whereas non-electric components such as plastic scintillating materials, adhesives, cable insulation, and other organic polymers are adequately tested with ionizing radiation only. Test standards are discussed with respect to irradiation techniques, environmental factors, dosimetry, and mechanisms whereby various materials are damaged. It is emphasized that radiation sources should be chosen to duplicate as much as possible the expected SSC environment and that the effects from ionizing particles and from neutrons be investigated separately. Radiation damage tests at reactors must be designed with particular care complex spectra of neutrons and gamma rays are produced at such facilities. It is also essential to investigate dose-rate effects since they are known to be important in many cases. The required irradiations may last several months and are most easily carried out with dedicated radioactive sources. Environmental factors such as the presence of oxygen when testing plastic scintillators, or temperature when measuring semiconductor annealing effects, must also be taken into account. The importance of reliable dosimetry is stressed and suitable references cited. Finally, it is noted that an understanding of the mechanisms for radiation damage in semiconductor and other materials is important in planning irradiations and evaluating results

  12. State of damage of radiation facilities in great Hanshin earthquake

    International Nuclear Information System (INIS)

    1995-01-01

    The southern Hyogo Prefecture earthquake of magnitude 7.2 occurred in the early morning of January 17, 1995. The outline of the earthquake and dead and injured, the damages of buildings, life lines, roads, railways and harbors, liquefaction phenomena, the state of occurrence of fires and so on are reported. The districts where the earthquakes of magnitude 5 or stronger occurred, and the radiation facilities in those districts are shown. The state of damage of radiation facilities in past earthquakes is summarized. From January 17 to 19 after the earthquake, Science and Technology Agency gave necessary instruction to and heard the state of damage from 79 permitted facilities in the areas of magnitude 7 or 6 by telephone, and received the report that there was not the fear of radiation damage in all facilities. Also the state of damage of radiation facilities was investigated at the actual places, and the questionnaires on the state of radiation facilities and the action at the time of the earthquake were performed. The state of radiation facilities accompanying the earthquake is reported. The matters to be reflected to the countermeasures to earthquakes anew for the protection of facilities, communication system, facility checkup system and the resumption of use are pointed out. (K.I.)

  13. The Status of Radiation Damage Experiments

    International Nuclear Information System (INIS)

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

    2001-01-01

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

  14. Radiation damage of polymers in ultrasonic fields

    International Nuclear Information System (INIS)

    Anbalagan, Poornnima

    2008-01-01

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

  15. Radiation damage of polymers in ultrasonic fields

    Energy Technology Data Exchange (ETDEWEB)

    Anbalagan, Poornnima

    2008-07-01

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

  16. Gallium arsenide solar cell radiation damage study

    Science.gov (United States)

    Maurer, R. H.; Herbert, G. A.; Kinnison, J. D.; Meulenberg, A.

    1989-01-01

    A thorough analysis has been made of electron- and proton- damaged GaAs solar cells suitable for use in space. It is found that, although some electrical parametric data and spectral response data are quite similar, the type of damage due to the two types of radiation is different. An I-V analysis model shows that electrons damage the bulk of the cell and its currents relatively more, while protons damage the junction of the cell and its voltages more. It is suggested that multiple defects due to protons in a strong field region such as a p/n junction cause the greater degradation in cell voltage, whereas the individual point defects in the quasi-neutral minority-carrier-diffusion regions due to electrons cause the greater degradation in cell current and spectral response.

  17. Enhancement of radiation damage in germinating wheat seeds by hyperthermia

    International Nuclear Information System (INIS)

    Guo Fangqing; Gu Ruiqi

    1994-01-01

    Enhancement of X-ray induced radiation damage in germinating wheat seeds by heat treatment (44 degree C or 41 degree C, 20 min) has been investigated. The enhancement effect of heat treatment after irradiation was more significant than that of heat treatment before irradiation at dose range of 4.3-8.6 Gy. It was observed that germinating wheat seeds were very sensitive to heat treatment within 15 min after irradiation, which indicated that the repair of radiation damage was very active and rapid in a short period after irradiation. The repair of radiation damage in interval of fractionated irradiation was severely inhibited by heat treatment. The sensitivity of seeds to heat treatment corresponded with the levels of their repair activities. The more active the repairs of the seeds are, the more sensitive to heat treatment the seeds show. It was assumed that the enhancement of radiation damage by heat treatment in germinating wheat seeds was attributed to the inhibition of radiation damage repair by heat treatment, which is similar to the results of animal experiments

  18. Radiation damage studies of nuclear structural materials

    International Nuclear Information System (INIS)

    Barat, P.

    2012-01-01

    Maximum utilization of fuel in nuclear reactors is one of the important aspects for operating them economically. The main hindrance to achieve this higher burnups of nuclear fuel for the nuclear reactors is the possibility of the failure of the metallic core components during their operation. Thus, the study of the cause of the possibility of failure of these metallic structural materials of nuclear reactors during full power operation due to radiation damage, suffered inside the reactor core, is an important field of studies bearing the basic to industrial scientific views.The variation of the microstructure of the metallic core components of the nuclear reactors due to radiation damage causes enormous variation in the structure and mechanical properties. A firm understanding of this variation of the mechanical properties with the variation of microstructure will serve as a guide for creating new, more radiation-tolerant materials. In our centre we have irradiated structural materials of Indian nuclear reactors by charged particles from accelerator to generate radiation damage and studied the some aspects of the variation of microstructure by X-ray diffraction studies. Results achieved in this regards, will be presented. (author)

  19. Study on DNA damages induced by UV radiation

    International Nuclear Information System (INIS)

    Doan Hong Van; Dinh Ba Tuan; Tran Tuan Anh; Nguyen Thuy Ngan; Ta Bich Thuan; Vo Thi Thuong Lan; Tran Minh Quynh; Nguyen Thi Thom

    2015-01-01

    DNA damages in Escherichia coli (E. coli) exposed to UV radiation have been investigated. After 30 min of exposure to UV radiation of 5 mJ/cm 2 , the growth of E. coli in LB broth medium was about only 10% in compared with non-irradiated one. This results suggested that the UV radiation caused the damages for E. coli genome resulted in reduction in its growth and survival, and those lesions can be somewhat recovered. For both solutions of plasmid DNAs and E. coli cells containing plasmid DNA, this dose also caused the breakage on single and double strands of DNA, shifted the morphology of DNA plasmid from supercoiled to circular and linear forms. The formation of pyrimidine dimers upon UV radiation significantly reduced when the DNA was irradiated in the presence of Ganoderma lucidum extract. Thus, studies on UV-induced DNA damage at molecular level are very essential to determine the UV radiation doses corresponding to the DNA damages, especially for creation and selection of useful radiation-induced mutants, as well as elucidation the protective effects of the specific compounds against UV light. (author)

  20. Radiation Damage in the LHCb VELO

    CERN Multimedia

    Harrison, Jon

    2011-01-01

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

  1. Pathology of radiation induced lung damage

    International Nuclear Information System (INIS)

    Kawabata, Yoshinori; Murata, Yoshihiko; Ogata, Hideo; Katagiri, Shiro; Sugita, Hironobu; Iwai, Kazuo; Sakurai, Isamu.

    1985-01-01

    We examined pathological findings of radiation induced lung damage. Twenty-three cases are chosen from our hospital autopsy cases for 9 years, which fulfil strict criteria of radiation lung damage. Lung damage could be classified into 3 groups : 1) interstitial pneumonia type (9 cases), 2) intermediate pneumonia type (8 cases), and 3) alveolar pneumonia type (6 cases), according to the degree of intra-luminal exudation. These classification is well correlated with clinical findings. Pathological alveolar pneumonia type corresponds to symptomatic, radiologic ground glass pneumonic shadow. And pathologic interstitial type corresponds to clinical asymptomatic, radiologic reticulo-nodular shadow. From the clinico-pathological view point these classification is reasonable one. Radiation affects many lung structures and showed characteristic feature of repair. Elastofibrosis of the alveolar wall is observed in every cases, obstructive bronchiolitis are observed in 5 cases, and obstructive bronchiolitis in 9 cases. They are remarkable additional findings. Thickening of the interlobular septum, broncho-vascular connective tissue, and pleural layer are observed in every cases together with vascular lesions. (author)

  2. Radiation damage in the alkali halide crystals

    International Nuclear Information System (INIS)

    Diller, K.M.

    1975-10-01

    A general review is given of the experimental data on radiation damage in the alkali halide crystals. A report is presented of an experimental investigation of irradiation produced interstitial dislocation loops in NaCl. These loops are found to exhibit the usual growth and coarsening behaviour during thermal annealing which operates by a glide and self-climb mechanism. It is shown that the recombination of defects in these crystals is a two stage process, and that the loss of interstitials stabilized at the loops is caused by extrinsic vacancies. The theoretical techniques used in simulating point defects in ionic crystals are described. Shell model potentials are derived for all the alkali halide crystals by fitting to bulk crystal data. The fitting is supplemented by calculations of the repulsive second neighbour interactions using methods based on the simple electron gas model. The properties of intrinsic and substitutional impurity defects are calculated. The HADES computer program is used in all the defect calculations. Finally the report returns to the problems of irradiation produced interstitial defects. The properties of H centres are discussed; their structure, formation energies, trapping at impurities and dimerization. The structure, formation energies and mobility of the intermediate and final molecular defects are then discussed. The thermodynamics of interstitial loop formation is considered for all the alklai halide crystals. The nucleation of interstitial loops in NaCl and NaBr is discussed, and the recombination of interstitial and vacancy defects. The models are found to account for all the main features of the experimental data. (author)

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

    CERN Document Server

    Kantoglu, O

    2002-01-01

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

  4. Investigation of DNA damage and repair mechanism using deinococcus radiodurans

    International Nuclear Information System (INIS)

    Lau How Mooi; Kikuchi, M.; Kobayashi, Y.; Narumi, I.; Watanabe, H.

    1997-01-01

    Deninococcus Radiodurans, formerly known as Micrococcus Radiodurans, is a popular bacterium because of its high resistance to damage by carcinogens such as ionizing radiation (Dean et. al. 1966; Kitayama and Matsuyama 1968) and UV radiation (Gasvon et. al., 1995; Arrange et. al. 1993). In this report, we investigated the high resistance to ionizing radiation by this bacterium. The bacteria had been exposed from I to 5 kGy of gamma radiation and then incubated in TGY medium to study their ability to repair the broken DNA. The repair time was measured by Pulse Field Gel Electrophoresis (PFGE) method. The repair time for each dose was determined. Also in order to ensure that the repair was perfect, the bacterium was subjected to a second exposure of ionizing radiation after it has fully repaired. It was found that the 'second' repair characteristic was similar to the first repair. This confirmed that the repair after the exposure to the ionizing radiation was perfect

  5. Ultraviolet radiation, sun damage and preventing

    International Nuclear Information System (INIS)

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

    2013-01-01

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

  6. Compilation of radiation damage test data. I

    International Nuclear Information System (INIS)

    Schoenbacher, H.; Stolarz-Izycka, A.

    1979-01-01

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

  7. Neutron radiation damage studies on silicon detectors

    International Nuclear Information System (INIS)

    Li, Zheng; Chen, W.; Kraner, H.W.

    1990-10-01

    Effects of neutron radiation on electrical properties of Si detectors have been studied. At high neutron fluence (Φ n ≥ 10 12 n/cm 2 ), C-V characteristics of detectors with high resistivities (ρ ≥ 1 kΩ-cm) become frequency dependent. A two-trap level model describing this frequency dependent effect is proposed. Room temperature anneal of neutron damaged (at LN 2 temperature) detectors shows three anneal stages, while only two anneal stages were observed in elevated temperature anneal. 19 refs., 14 figs

  8. Radiation damage to DNA-protein complexes

    Czech Academy of Sciences Publication Activity Database

    Spotheim-Maurizot, M.; Davídková, Marie

    2011-01-01

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

  9. Studies on the strategies of minimizing radiation damage

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Hee Yong; Sohn, Young Sook

    1998-04-01

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

  10. Studies on the strategies of minimizing radiation damage

    International Nuclear Information System (INIS)

    Chung, Hee Yong; Sohn, Young Sook

    1998-04-01

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

  11. Localized defects in radiation-damaged zircon

    Science.gov (United States)

    Rios; Malcherek; Salje; Domeneghetti

    2000-12-01

    The crystal structure of a radiation-damaged natural zircon, ZrSiO(4) (alpha-decay radiation dose is ca 1.8 x 10(18) alpha-decay events g(-1)), has been determined. The anisotropic unit-cell swelling observed in the early stages of the amorphization process (0.17% along the a axis and 0.62% along the c axis compared with the undamaged material) is a consequence of the anisotropy of the expansion of ZrO(8) polyhedra. Larger anisotropic displacement parameters were found for Zr and O atoms, indicating that the distortion produced by alpha particle-induced localized defects mainly affects the ZrO(8) unit. The overall shape of SiO(4) tetrahedra remains essentially undistorted, while Si-O bonds are found to lengthen by 0.43%.

  12. Nanosecond laser damage investigations in nonlinear crystals

    International Nuclear Information System (INIS)

    Hildenbrand, A.

    2008-11-01

    Lasers become more and more powerful and compact. This raises laser induced damage issues in optical components, especially in nonlinear crystals. This thesis deals with nanosecond laser damage investigations in nonlinear crystals used for frequency conversion (KTP, KDP, LBO) and electro-optic applications (RTP, KDP). First, due to nonlinear and anisotropic effects of the crystals, the development of a metrology dedicated to laser damage studies of crystals was necessary. This metrology was then applied to the study of KTP and RTP isomorphous crystals, and LBO crystals. The influence of many parameters on the laser damage resistance, such as wavelength, polarization and crystal orientation, was studied allowing a better understanding of the laser damage phenomena in these crystals. Moreover, laser induced damage characterization was realized on these crystals with a high number of shots and in the real operating conditions, showing that the laser damage threshold of the component depends on its use. For example, the coexistence of multiple wavelengths inside the crystal takes a great part in the damage phenomena. (author)

  13. Radiation damage to DNA-binding proteins

    International Nuclear Information System (INIS)

    Culard, G.; Eon, S.; DeVuyst, G.; Charlier, M.; Spotheim-Maurizot, M.

    2003-01-01

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

  14. Solar radiation and mitochondrial DNA damage

    International Nuclear Information System (INIS)

    Hill, H.Z.; Locitzer, J.; Nassrin, E.; Ogbonnaya, A.; Hubbard, K.

    2003-01-01

    The 16.6 kB human mitochondrial DNA contains two homologous 13 base pair direct repeats separated by about 5 kB. During asynchronous mitochondrial DNA replication, the distant repeat sequences are thought to anneal, resulting in the looping out of a portion of the non-template strand which is subsequently deleted as a result of interaction with reactive oxygen species (ROS). A normal daughter and a deleted daughter mitochondrion result from such insults. This deletion has been termed the common deletion as it is the most frequent of the known mitochondrial DNA deletions. The common deletion is present in high frequency in several mitochondrial disorders, accumulates with age in slow turnover tissues and is increased in sun-exposed skin. Berneburg, et al. (Photochem. Photobiol. 66: 271, 1997) induced the common deletion in normal human fibroblasts after repeated exposures to UVA. In this study, the common deletion has been shown to be induced by repeated non-lethal exposures to FS20 sunlamp irradiation. Increases in the common deletion were demonstrated using nested PCR which produced a 303 bp product that was compared to a 324 bp product that required the presence of the undeleted 5 kB region. The cells were exposed to 10 repeated doses ranging from 0.5 (UVB) - 0.24 (UVA) J/sq m to 14.4 (UVB) - 5.8 J/sq m (UVA) measured using a UVX digital radiometer and UVB and UVA detectors respectively. Comparison with the earlier study by Berneberg, et al. suggests that this type of simulated solar damage is considerably more effective in fewer exposures than UVA radiation alone. The common deletion provides a cytoplasmic end-point for ROS damage produced by low dose chronic irradiations and other low level toxic exposures and should prove useful in evaluating cytoplasmic damage produced by ionizing radiation as well

  15. Molecular mechanisms in radiation damage to DNA: Final report

    International Nuclear Information System (INIS)

    Osman, R.

    1996-01-01

    The objectives of this work were to elucidate the molecular mechanisms that were responsible for radiation-induced DNA damage. The studies were based on theoretical explorations of possible mechanisms that link initial radiation damage in the form of base and sugar damage to conformational changes in DNA

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

    Energy Technology Data Exchange (ETDEWEB)

    Zehnder, M.

    2007-03-15

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

  17. Non-Thermal Electromagnetic Radiation Damage to Lens Epithelium

    OpenAIRE

    Bormusov, Elvira; P.Andley, Usha; Sharon, Naomi; Sch?chter, Levi; Lahav, Assaf; Dovrat, Ahuva

    2008-01-01

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

  18. Laser damage investigations of Cu mirrors

    International Nuclear Information System (INIS)

    Gorshkov, A.; Bel'bas, I.; Maslov, M.; Sannikov, V.; Vukolov, K.

    2005-01-01

    Laser tests were performed on Cu mirrors as 'first mirror' prototypes for laser diagnostics. Data on laser damage thresholds of surfaces under the influence of pulsed YAG laser radiation were obtained for single shot and after about 1.5 x 10 5 shots. The experiments were carried out using three types of copper mirrors: diamond-turned mirror, diamond-turned substrate with copper coating and reflection grating on a copper coated mirror. The lifetime of the copper mirrors was tested. Diffusion scattering was used as a monitor of mirror surface quality. The degradation of diamond turned copper mirrors in multiple pulse laser irradiation appears to be in satisfactory accordance with a model for multipulse laser damage of metal mirrors up to 1.5 x 10 5 laser pulses. The degradation of copper coated mirrors has a more complicated behaviour

  19. Fluorescence studies on radiation oxidative damage to membranes ...

    Indian Academy of Sciences (India)

    Unknown

    Keywords. Membrane oxidative damage; cellular radiosensitivity; DPH fluorescence; lipid peroxidation; liposomal membrane; thymocyte membrane permeability. 1. Introduction. Radiation damage to cells and tissues involves generation of reactive oxygen species. (ROS) followed by alterations in lipids, DNA and proteins, ...

  20. Compilation of radiation damage test data. II

    International Nuclear Information System (INIS)

    Schoenbacher, H.; Stolarz-Izycka, A.

    1979-01-01

    This report summarizes radiation damage test data on thermosetting and thermoplastic resins, with the main emphasis on epoxy resins used for magnet coil insulations. Also, other materials such as polyesters, phenolics, polyurethanes, silicones, etc., are represented. The materials have been irradiated in a nuclear reactor to integrated absorbed doses between 5x10 6 Gy and 1x10 8 Gy. The mechanical properties, e.g. the flexural strength, deflection at break, and tangent modulus of elasticity, have been measured on irradiated and non-irradiated samples. The results are given as variation of these parameters versus absorbed dose and are presented in the form of tables and graphs. The tested materials are catalogued in alphabetical order. (Auth.)

  1. Compilation of radiation damage test data

    International Nuclear Information System (INIS)

    Schoenbacher, H.; Tavlet, M.

    1989-01-01

    This report summarizes radiation damage test data on commercially available organic cable insulation and jacket materials: Ethylene-propylene rubbers, polyethylenes, polyurethanes, silicone rubbers, and copolymers based on polyethylene. The materials have been irradiated either in a nuclear reactor, or with a cobalt-60 source, or in the CERN accelerators, at different dose rates. The absorbed doses were between 10 3 and 5x10 6 Gy. Mechanical properties, e.g. tensile strength, elongation at break, and hardness, have been tested on irradiated and non-irradiated samples, according to the recommendations of the International Electrotechnical Commission. The results are presented in the form of tables and graphs to show the effect of the absorbed dose on the measured properties. (orig.)

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

    Science.gov (United States)

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

    2008-05-21

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

  3. Thermal annealing of natural, radiation-damaged pyrochlore

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-03-01

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

  4. Radiation damage of organic composite material for fusion magnet

    International Nuclear Information System (INIS)

    Nishijima, S.; Okada, T.

    1991-01-01

    Fusion superconducting magnets are 'series machines' in the sense that the complete magnet may decrease in overall performance when even one component does not deliver the expected performance. Such magnets are often operated under severe conditions, such as radiation environments and those materials which are most prone to damage under such radiation environments demand particular attention. The component most sensitive to radiation damage in the fusion magnet is the organic composite material used for insulation, usually glass fibre reinforced plastic (GFRP). Radiation resistant GFRPs have been developed and these will be discussed in this work, together with other aspects of radiation damage of organic composite materials. (author)

  5. Basic aspects of spallation radiation damage to materials

    Energy Technology Data Exchange (ETDEWEB)

    Wechsler, M.S.; Lin, C. [North Carolina State Univ., Raleigh, NC (United States); Sommer, W.F. [Los Alamos National Laboratory, NM (United States)

    1995-10-01

    The nature of radiation effects, as learned from investigations using reactor neutron irradiations, is reviewed, and its relevance to spallation radiation damage to materials in accelerator-driven neutron sources is discussed. Property changes upon irradiation are due to (1) displaced atoms, producing vacancy and interstitial defect clusters, which cause radiation hardening and embrittlement; (2) helium production, the helium then forming bubbles, which engenders high-temperature grain-boundary fracture; and (3) transmutations, which means that impurity concentrations are introduced. Methods for analyzing displacement production are related, and recent calculations of displacement cross sections using SPECTER and LAHET are described, with special reference to tungsten, a major candidate for a target material in accelerator-driven neutron systems.

  6. Radiation damage of DNA. Model for direct ionization of DNA

    International Nuclear Information System (INIS)

    Kobayashi, Kazuo; Tagawa, Seiichi

    2004-01-01

    Current aspects of radiation damage of DNA, particularly induced by the direct effect of radiation, and author's method of pulse radiolysis are described in relation to behavior of ions formed by radiation and active principles to induce the strand break. In irradiation of DNA solution in water, the direct effect of radiation is derived from ionization of DNA itself and indirect one, from the reaction between DNA and radicals generated from water molecules and the former direct one has been scarcely investigated due to difficulty of experimental approach. Radicals generated in sugar moiety of DNA are shown important in the strand break by recent studies on crystalline DNA irradiated by X-ray, DNA solution by electron and photon beams, hydrated DNA by γ-ray and by high linear energy transfer (LET) ion. Author's pulse radiolysis studies have revealed behaviors of guanine and adenine radical cations in dynamics of DNA oxidation. Since reactions described are the model, the experimental approach is thought necessary for elucidation of the actually occurring DNA damage in living cells. (N.I.)

  7. Fluorescence studies on radiation oxidative damage to membranes ...

    Indian Academy of Sciences (India)

    Radiation oxidative damage to plasma membrane and its consequences to cellular radiosensitivity have received increasing attention in the past few years. This review gives a brief account of radiation oxidative damage in model and cellular membranes with particular emphasis on results from our laboratory. Fluorescence ...

  8. Radiation damage to DNA: the effect of LET

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-03-01

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

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

    International Nuclear Information System (INIS)

    Moseley, B.E.B.

    1984-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-03-01

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

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

    International Nuclear Information System (INIS)

    Matsumoto, Yoshiyuki

    2000-01-01

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

  12. Effects of radiation damage on the silicon lattice

    Science.gov (United States)

    Dumas, Katherine A.; Lowry, Lynn; Russo, O. Louis

    1987-01-01

    Silicon was irradiated with both proton and electron particle beams in order to investigate changes in the structural and optical properties of the lattice as a result of the radiation damage. Lattice expansions occurred when large strain fields (+0.34 percent) developed after 1- and 3-MeV proton bombardment. The strain was a factor of three less after 1-MeV electron irradiation. Average increases of approximately 22 meV in the 3.46-eV interband energy gap and 14 meV in the Lorentz broadening parameter were measured after the electron irradiation.

  13. Heavy ion linear accelerator for radiation damage studies of materials

    Energy Technology Data Exchange (ETDEWEB)

    Kutsaev, Sergey V.; Mustapha, Brahim; Ostroumov, Peter N.; Nolen, Jerry; Barcikowski, Albert; Pellin, Michael; Yacout, Abdellatif

    2017-03-01

    A new eXtreme MATerial (XMAT) research facility is being proposed at Argonne National Laboratory to enable rapid in situ mesoscale bulk analysis of ion radiation damage in advanced materials and nuclear fuels. This facility combines a new heavy-ion accelerator with the existing high-energy X-ray analysis capability of the Argonne Advanced Photon Source. The heavy-ion accelerator and target complex will enable experimenters to emulate the environment of a nuclear reactor making possible the study of fission fragment damage in materials. Material scientists will be able to use the measured material parameters to validate computer simulation codes and extrapolate the response of the material in a nuclear reactor environment. Utilizing a new heavy-ion accelerator will provide the appropriate energies and intensities to study these effects with beam intensities which allow experiments to run over hours or days instead of years. The XMAT facility will use a CW heavy-ion accelerator capable of providing beams of any stable isotope with adjustable energy up to 1.2 MeV/u for U-238(50+) and 1.7 MeV for protons. This energy is crucial to the design since it well mimics fission fragments that provide the major portion of the damage in nuclear fuels. The energy also allows damage to be created far from the surface of the material allowing bulk radiation damage effects to be investigated. The XMAT ion linac includes an electron cyclotron resonance ion source, a normal-conducting radio-frequency quadrupole and four normal-conducting multi-gap quarter-wave resonators operating at 60.625 MHz. This paper presents the 3D multi-physics design and analysis of the accelerating structures and beam dynamics studies of the linac.

  14. UV Radiation Damage and Bacterial DNA Repair Systems

    Science.gov (United States)

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

    2006-01-01

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

  15. Radiation damage with biological specimens and organic materials

    International Nuclear Information System (INIS)

    Glaeser, R.M.

    1979-01-01

    The radiation damage referred to in this chapter is defined as any changes in the physical structure or chemical makeup of the specimen which occur as a result of exposure to the electron beam. Radiation damage occurs in organic materials predominantly as a consequence of inelastic scattering of the incident electrons which frequently results in molecular ionization and radiolysis. Other types of radiation damage which can occur are specimen etching, which occurs as the result of synergistic action of electron irradiation and the presence of certain residual gasses, and specimen heating which occurs only at electron current densities that are large on the scale of ionization damage. The primary events in radiation physics and radiation chemistry and signal-to-noise considerations are also discussed in some detail

  16. Radiation damage studies on water-embedded biomolecules

    Energy Technology Data Exchange (ETDEWEB)

    Bari, Sadia; Inklaar, Maarten; Seijen, Femke van; Hoekstra, Ronnie; Schlathoelter, Thomas [KVI Atomic Physics, University of Groningen (Netherlands); Gosset, Dominik [ENSIAME, Valenciennes (France)

    2008-07-01

    The current increasing social and corporate interest in proton- and heavy ion-therapy of malignant tumors now results in the construction of first particle treatment centers. The chemical and biological aspects of biological radiation damage have been studied in great detail. However, little is known about biological radiation action on the molecular level and fs-timescales. First studies focused on gas phase DNA related molecules and neglected influences of the chemical environment. To investigate these influences we built an electrospray ionization (ESI) source to form clusters from DNA molecules surrounded by water. Cooling and mass selection in a RF quadrupole ion trap ensures sufficient cluster density. After keV-ion irradiation collision products are extracted from the trap into a time-of-flight mass spectrometer.

  17. Photobiological aspects of radiation damage to bacteria

    International Nuclear Information System (INIS)

    Myasnik, M.N.; Skvortsov, V.G.; Sokolov, V.A.

    1981-01-01

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

  18. Radiation damage monitoring in the ATLAS pixel detector

    International Nuclear Information System (INIS)

    Seidel, Sally

    2013-01-01

    We describe the implementation of radiation damage monitoring using measurement of leakage current in the ATLAS silicon pixel sensors. The dependence of the leakage current upon the integrated luminosity is presented. The measurement of the radiation damage corresponding to an integrated luminosity 5.6 fb −1 is presented along with a comparison to a model. -- Highlights: ► Radiation damage monitoring via silicon leakage current is implemented in the ATLAS (LHC) pixel detector. ► Leakage currents measured are consistent with the Hamburg/Dortmund model. ► This information can be used to validate the ATLAS simulation model.

  19. Fundamental Technology Development for Radiation Damage in Nuclear Materials

    International Nuclear Information System (INIS)

    Kwon, Sang Chul; Kwon, J. H.; Kim, E. S. and others

    2005-04-01

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

  20. Radiation damage on sub-cellular scales: beyond DNA.

    Science.gov (United States)

    Byrne, H L; McNamara, A L; Domanova, W; Guatelli, S; Kuncic, Z

    2013-03-07

    This study investigates a model cell as a target for low-dose radiation using Monte Carlo simulations. Mono-energetic electrons and photons are used with initial energies between 10 and 50 keV, relevant to out-of-field radiotherapy scenarios where modern treatment modalities expose relatively large amounts of healthy tissue to low-dose radiation, and also to microbeam cell irradiation studies which show the importance of the cytoplasm as a radiation target. The relative proportions of number of ionizations and total energy deposit in the nucleus and cytoplasm are calculated. We show that for a macroscopic dose of no more than 1 Gy only a few hundred ionizations occur in the nucleus volume whereas the number of ionizations in the cytoplasm is over a magnitude larger. We find that the cell geometry can have an appreciable effect on the energy deposit in the cell and can cause a nonlinear increase in energy deposit with cytoplasm density. We also show that changing the nucleus volume has negligible effect on the total energy deposit but alters the relative proportion deposited in the nucleus and cytoplasm; the nucleus volume must increase to approximately the same volume as the cytoplasm before the energy deposit in the nucleus matches that in the cytoplasm. Additionally we find that energy deposited by electrons is generally insensitive to spatial variations in chemical composition, which can be attributed to negligible differences in electron stopping power for cytoplasm and nucleus materials. On the other hand, we find that chemical composition can affect energy deposited by photons due to non-negligible differences in attenuation coefficients. These results are of relevance in considering radiation effects in healthy cells, which tend to have smaller nuclei. Our results further show that the cytoplasm and organelles residing therein can be important targets for low-dose radiation damage in healthy cells and warrant investigation as much as the conventional focus

  1. Radiation damage on sub-cellular scales: beyond DNA

    International Nuclear Information System (INIS)

    Byrne, H L; McNamara, A L; Domanova, W; Kuncic, Z; Guatelli, S

    2013-01-01

    This study investigates a model cell as a target for low-dose radiation using Monte Carlo simulations. Mono-energetic electrons and photons are used with initial energies between 10 and 50 keV, relevant to out-of-field radiotherapy scenarios where modern treatment modalities expose relatively large amounts of healthy tissue to low-dose radiation, and also to microbeam cell irradiation studies which show the importance of the cytoplasm as a radiation target. The relative proportions of number of ionizations and total energy deposit in the nucleus and cytoplasm are calculated. We show that for a macroscopic dose of no more than 1 Gy only a few hundred ionizations occur in the nucleus volume whereas the number of ionizations in the cytoplasm is over a magnitude larger. We find that the cell geometry can have an appreciable effect on the energy deposit in the cell and can cause a nonlinear increase in energy deposit with cytoplasm density. We also show that changing the nucleus volume has negligible effect on the total energy deposit but alters the relative proportion deposited in the nucleus and cytoplasm; the nucleus volume must increase to approximately the same volume as the cytoplasm before the energy deposit in the nucleus matches that in the cytoplasm. Additionally we find that energy deposited by electrons is generally insensitive to spatial variations in chemical composition, which can be attributed to negligible differences in electron stopping power for cytoplasm and nucleus materials. On the other hand, we find that chemical composition can affect energy deposited by photons due to non-negligible differences in attenuation coefficients. These results are of relevance in considering radiation effects in healthy cells, which tend to have smaller nuclei. Our results further show that the cytoplasm and organelles residing therein can be important targets for low-dose radiation damage in healthy cells and warrant investigation as much as the conventional focus

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

    CERN Document Server

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

    1999-01-01

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

  3. DNA Damage by Radiation in Tradescantia Leaf Cells

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-04-15

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

  4. Single Molecule Scanning of DNA Radiation Oxidative Damage Project

    Data.gov (United States)

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

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

    CERN Document Server

    Kiselev, Daniela

    2013-01-01

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

  6. Single Molecule Scanning of DNA Radiation Oxidative Damage, Phase I

    Data.gov (United States)

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

  7. Computer simulation of radiation damage in gallium arsenide

    Science.gov (United States)

    Stith, John J.; Davenport, James C.; Copeland, Randolph L.

    1989-01-01

    A version of the binary-collision simulation code MARLOWE was used to study the spatial characteristics of radiation damage in proton and electron irradiated gallium arsenide. Comparisons made with the experimental results proved to be encouraging.

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

    Science.gov (United States)

    Hopkins, Jesse B; Thorne, Robert E

    2016-06-01

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

  9. Automated analysis of damages for radiation in plastics surfaces

    International Nuclear Information System (INIS)

    Andrade, C.; Camacho M, E.; Tavera, L.; Balcazar, M.

    1990-02-01

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

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

    CERN Document Server

    Hill, M A

    1999-01-01

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

  11. A review on radiation damage of erythrocyte membranes

    International Nuclear Information System (INIS)

    Wang Junling; Wang Weidong; Qin Guangyong

    2007-01-01

    Biomembrane has very important biological function. Its damage will seriously disturb the directivity, the orderly nature and coordination of cell metabolism, and finally causes the cell death. This paper reviewed the effects of radiation damage on erythrocyte membrane in membrane composition, membrane function and oxidation resistance system. (authors)

  12. Chemical aspects of radiation damage processes: radiolysis

    International Nuclear Information System (INIS)

    Asmus, K.D.

    1975-01-01

    The formation of primary species and radiation chemical yields are discussed. In a section on chemical scavenging of primary species the author considers scavenging kinetics and competition reactions and gives a brief outline of some experimental methods. The radiation chemistry of aqueous solutions is discussed as an example for polar solvents. Cyclohexane is used as an example for non-polar solvents. The importance of excited states and energy transfer is considered. Reactions in the solid state are discussed and results on linear energy transfer and average ion pair formation for various kinds of radiation are surveyed. (B.R.H.)

  13. Radiation damage of gallium arsenide production cells

    Science.gov (United States)

    Mardesich, N.; Joslin, D.; Garlick, J.; Lillington, D.; Gillanders, M.; Cavicchi, B.; Scott-Monck, J.; Kachare, R.; Anspaugh, B.

    1987-01-01

    High efficiency liquid phase epitaxy (LPE) gallium arsenide cells were irradiated with 1 Mev electrons up to fluences of 1 times 10 to the 16th power cm-2. Measurements of spectral response and dark and illuminated I-V data were made at each fluence and then, using computer codes, the experimental data was fitted to gallium arsenide cell models. In this way it was possible to determine the extent of the damage, and hence damage coefficients in both the emitter and base of the cell.

  14. Role of radiation-damage analysis in the fusion program

    International Nuclear Information System (INIS)

    Doran, D.G.

    1982-09-01

    The objective of radiation-damage analysis is the prediction of the performance of facility components exposed to a radiation environment. The US Magnetic Fusion Energy materials program includes an explicit damage-analysis activity within the Damage Analysis and Fundamental Studies (DAFS) Program. Many of the papers in this volume report work done directly or indirectly in support of the DAFS program. The emphasis is on developing procedures, based on an understanding of damage mechanisms, for applying data obtained in diverse radiation environments to the prediction of component behavior in fusion devices. It is assumed that the Fusion Materials Irradiation Test Facility will be available in the late 1980's to test (and calibrate where necessary) correlation procedures to the high fluences expected in commercial reactors

  15. The role of radiation damage analysis in the fusion program

    International Nuclear Information System (INIS)

    Doran, D.G.

    1983-01-01

    The objective of radiation damage analysis is the prediction of the performance of facility components exposed to a radiation environment. The US Magnetic Fusion Energy materials program includes an explicit damage analysis activity within the Damage Analysis and Fundamental Studies (DAFS) Program. Many of the papers in these Proceedings report work done directly or indirectly in support of the DAFS program. The emphasis of this program is on developing procedures, based on an understanding of damage mechanisms, for applying data obtained in diverse radiation environments to the prediction of component behavior in fusion devices. It is assumed that the Fusion Materials Irradiation Test Facility will be available in the late 1980s to test (and calibrate where necessary) correlation procedures to the high fluences expected in commercial reactors. (orig.)

  16. Properties and recrystallization of radiation damaged pyrochlore and titanite

    Energy Technology Data Exchange (ETDEWEB)

    Zietlow, Peter

    2016-11-02

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

  17. Investigation of radiation damage in lead

    International Nuclear Information System (INIS)

    Boehm, R.; Christiansen, J.; Hammer, E.; Heubes, P.; Keitel, R.; Klinger, W.; Loeffler, W.; Sandner, W.; Schatz, G.; Schultheiss, C.

    1977-01-01

    The experiments have been carried out on the Hamburg university cyclotron. The 8 + level of 210 Pb (T 1 / 2 = 112 nsec) populated via the 208 Pb (α,2n) 210 Po reaction at an injection energy of Esub(α) = 27 MeV was used for the measurements. The external magnetic field had a strength of 1.3 T; the target temperature was varied between 100 K and 530 K. (WL) [de

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-10-15

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

  19. Radiation damage at the molecular level: Nanodosimetry

    International Nuclear Information System (INIS)

    Blanco, F.; Munoz, A.; Lagares, J. I.; Nunez, L.; Garcia, G.

    2013-01-01

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

  20. Radioactivity, shielding, radiation damage, and remote handling

    International Nuclear Information System (INIS)

    Wilson, M.T.

    1975-01-01

    Proton beams of a few hundred million electron volts of energy are capable of inducing hundreds of curies of activity per microampere of beam intensity into the materials they intercept. This adds a new dimension to the parameters that must be considered when designing and operating a high-intensity accelerator facility. Large investments must be made in shielding. The shielding itself may become activated and require special considerations as to its composition, location, and method of handling. Equipment must be designed to withstand large radiation dosages. Items such as vacuum seals, water tubing, and electrical insulation must be fabricated from radiation-resistant materials. Methods of maintaining and replacing equipment are required that limit the radiation dosages to workers.The high-intensity facilities of LAMPF, SIN, and TRIUMF and the high-energy facility of FERMILAB have each evolved a philosophy of radiation handling that matches their particular machine and physical plant layouts. Special tooling, commercial manipulator systems, remote viewing, and other techniques of the hot cell and fission reactor realms are finding application within accelerator facilities. (U.S.)

  1. The suppressive effect of etoposide on recovery from sublethal radiation damage in Chinese hamster V 79 cells

    International Nuclear Information System (INIS)

    Saito, Tsutomu; Shimada, Yuji; Kawamori, Jiro; Kamata, Rikisaburo

    1992-01-01

    The combined effect of radiation and etoposide on the survival of cultured Chinese hamster V 79 cells was investigated. Cells in exponential growth phase were treated with various combinations of radiation and etoposide. The surviving fraction was assessed by colony formation. Etoposide significantly reduced so-called shoulder width, as expressed in Dq (quasithreshold dose), of radiation survival curves. The reduction depended on the increase of etoposide concentrations, although steepening of slopes of exponentially regressing portions of the radiation survival curves was slight. Split dose experiments showed that cells did not recover from sublethal radiation damage in the presence of low concentration of etoposide, although they did recover from sublethal radiation damage under a drug free condition. The results show the suppressive effect of etoposide on recovery from sublethal radiation damage. The effect of a sequential combination of radiation and etoposide was also investigated. The effect was more marked when the interval between radiation and etoposide was shorter regardless of the sequence. (author)

  2. THE ROLE OF RADIATION ACCIDENTS AND INDUSTRIAL APPLICATIONS OF IONIZING RADIATION SOURCES IN THE PROBLEM OF RADIATION DAMAGE

    OpenAIRE

    Кіхтенко, Ігор Миколайович

    2016-01-01

    Subject of research – the relevance of radiation damage at modern development of industry and medicine. In the world of radiation sources used in different fields of practice and their application in the future will increase, which greatly increases the likelihood of injury in a significant contingent of people.Research topic – the definition of the role of nuclear energy and the industrial use of ionizing radiation sources in the problem of radiation damage. The purpose of research – identif...

  3. Request from radiation damage evaluation in materials

    International Nuclear Information System (INIS)

    Fukuya, Koji; Kimura, Itsuro

    2003-01-01

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

  4. APD Properties and Recovery from Radiation Damage

    CERN Document Server

    Baccaro, Stefania; Caruso, S; Cavallari, Francesca; Dafinei, Ioan; Diemoz, Marcella; Emeliantchik, Igor; Festinesi, Armando; Longo, Egidio; Montecchi, Marco; Organtini, Giovanni; Rosi, G

    1997-01-01

    Avalanche photodiodes will be used to detect scintillation light from PWO crystals in the CMS electromagnetic calorimeter. Properties of Hamamatsu APD are reported special attention has been devoted to the study of radiation hardness and room temperature annealing. We found a fast recovery with a time constant of 1.3 days a medium fast recovery with a lifetime of the order of 10 days and indication of a third component with very long time constant of the order of 300 days.

  5. Minimizing radiation damage in nonlinear optical crystals

    Science.gov (United States)

    Cooke, D. Wayne; Bennett, Bryan L.; Cockroft, Nigel J.

    1998-01-01

    Methods are disclosed for minimizing laser induced damage to nonlinear crystals, such as KTP crystals, involving various means for electrically grounding the crystals in order to diffuse electrical discharges within the crystals caused by the incident laser beam. In certain embodiments, electrically conductive material is deposited onto or into surfaces of the nonlinear crystals and the electrically conductive surfaces are connected to an electrical ground. To minimize electrical discharges on crystal surfaces that are not covered by the grounded electrically conductive material, a vacuum may be created around the nonlinear crystal.

  6. XAFS studies of radiation damage in nuclear materials

    Science.gov (United States)

    Olive, Daniel Thomas

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

  7. Radiation induced oxidative damage modification by cholesterol in liposomal membrane

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, B.N. [Radiation Biology and Biochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai (India); Mishra, K.P. [Radiation Biology and Biochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai (India)

    1999-05-01

    Ionizing radiation induced structural and chemical alterations in egg lecithin liposomal membrane have been studied by measurements of lipid peroxides, conjugated diene and fluorescence polarization. Predominantly unilamellar phospholipid vesicles prepared by sonication procedure were subjected to radiation doses of {gamma}-rays from Co-60 in aerated, buffered aqueous suspensions. The oxidative damage in irradiated lipid molecules of liposomes has been determined spectrophotometrically by diene conjugate formation and thiobarbituric acid reactive (TBAR) method as a function of radiation dose. A correlation was found between the radiation dose applied (0.1-1 kGy) and the consequent lipid oxidation. The damage produced in irradiated liposomal membrane was measured by 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence decay and polarization. The observed decrease in DPH fluorescence and increase in polarization was found dependent on the radiation dose suggesting alterations in rigidity or organizational order in phospholipid bilayer after irradiation. Furthermore, irradiated liposome vesicles composed of cholesterol showed marked reduction in observed radiation mediated peroxide formation and significantly affected the DPH fluorescence parameters. The magnitude of these modifying effects were found dependent on the mole fraction of cholesterol. It is concluded that modulation of structural order in unilamellar vesicle membrane by variations in basic molecular components controlled the magnitude of lipid peroxidation and diene conjugate formation. These observations contribute to our understanding of mechanism of radical reaction mediated damage caused by ionizing radiation in phospholipid membrane.

  8. The dependence of radiation damage analysis on neutron dosimetry

    International Nuclear Information System (INIS)

    Goland, A.N.; Parkin, D.M.

    1977-01-01

    The characteristics of defect production in neutron spectra can be determined by utilizing neutron cross section data (e.g. ENDF/B), detailed neutron spectral data and radiation damage models. The combination of neutron cross section and spectral data is a fundamental starting point in applying damage models. Calculations using these data and damage models show that there are significant differences in the way defects are produced in various neutron spectra. Nonelastic events dominate the recoil energy distribution in high-energy neutron sources such as those based upon fusion and deuteron-breakup reactions. Therefore, high-energy neutron cross sections must be measured or calculated to supplement existing data files. Radiation damage models can then be used to further characterize the diverse neutron spectra

  9. Dependence of radiation damage analysis on neutron dosimetry

    International Nuclear Information System (INIS)

    Goland, A.N.; Parkin, D.M.

    1975-01-01

    The characteristics of defect production in neutron spectra can be determined by utilizing neutron cross section data (e.g. ENDF/B), detailed neutron spectral data and radiation damage models. The combination of neutron cross section and spectral data is a fundamental starting point in applying damage models. Calculations using these data and damage models show that there are significant differences in the way defects are produced in various neutron spectra. Nonelastic events dominate the recoil energy distribution in high-energy neutron sources such as those based upon fusion and deuteron-breakup reactions. Therefore, high-energy neutron cross sections must be measured or calculated to supplement existing data files. Radiation damage models can then be used to further characterize the diverse neutron spectra

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

    International Nuclear Information System (INIS)

    Milliat, F.

    2007-05-01

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

  11. Radiation damage effects on calorimeter compensation

    International Nuclear Information System (INIS)

    Gabriel, T.A.; Handler, T.

    1990-01-01

    An important consideration in the design of a detector that is to be used at the Superconducting Super Collider (SSC) is the response of the calorimeter to electromagnetic and hadronic particles and the equality of those responses for different types of particles at equal incident energies, i.e. compensation. However, as the simulations that are reported show, the compensation characteristics of a calorimeter can be seriously compromised over a relatively short period of time due to the large radiation levels that are expected in the SSC environment. 6 refs., 3 figs

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

    International Nuclear Information System (INIS)

    Piksaikin, V.

    1986-06-01

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

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

    Science.gov (United States)

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

    2008-12-01

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

  14. Radiation damage studies of silicon microstrip sensors

    CERN Document Server

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

    2000-01-01

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

  15. Radiation induced DNA damage and repair in mutagenesis

    International Nuclear Information System (INIS)

    Strniste, G.F.; Chen, D.J.; Okinaka, R.T.

    1987-01-01

    The central theme in cellular radiobiological research has been the mechanisms of radiation action and the physiological response of cells to this action. Considerable effort has been directed toward the characterization of radiation-induced DNA damage and the correlation of this damage to cellular genetic change that is expressed as mutation or initiating events leading to cellular transformation and ultimately carcinogenesis. In addition, there has been a significant advancement in their understanding of the role of DNA repair in the process of mutation leading to genetic change in cells. There is extensive literature concerning studies that address radiation action in both procaryotic and eucaryotic systems. This brief report will make no attempt to summarize this voluminous data but will focus on recent results from their laboratory of experiments in which they have examined, at both the cellular and molecular levels, the process of ionizing radiation-induced mutagenesis in cultured human cells

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

    International Nuclear Information System (INIS)

    Kurishita, A.; Ono, T.

    1992-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Y. Kawada

    2007-10-01

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

  18. Radiation-induced genetic damage and the prostaglandin system

    International Nuclear Information System (INIS)

    Das, U.N.; Rama Devi, G.

    1988-01-01

    Radiation is one of the sheet anchors of cancer therapy. More often than not radiation is used in combination with anticancer drugs and surgery in the management of cancer. The death of any cell can be observed if the dose of radiation to which it is exposed is sufficiently high. However, after low doses of radiation (precise values vary with the tissue) disturbances in cell proliferation can be observed which may include interference with mitosis and DNA synthesis. This can lead to the formation of cells with abnormal DNA, with qualitative and/or quantitative abnormalities. These effects of radiation are seen mainly in the tissues undergoing continual renewal such as mucosa, bone marrow, gonads etc., and the spectrum of damage ranging from progressive hypoplesia to total atrophy, depending on the dose. One of the late effects of radiation is the development of cancer

  19. Modification of radiation damage by naturally occurring substances

    International Nuclear Information System (INIS)

    Prasad, K.N.

    1984-01-01

    The major objectives of studying the modification of radiation sensitivity have been (1) to identify a compound that will produce a differential protection or sensitization of the effect of irradiation on normal and tumor tissue, and (2) to understand more about the mechanisms of radiation damage. In spite of massive research on this particular problem since World War II, the first objective remains elusive. During this period, numerous radioprotective and radiosensitizing agents have been identified. These agents have served as important biologic tools for increasing our understanding of radiation injuries. Most of these substances are synthetic compounds and are very toxic to humans. In addition, very few of the compounds provide differential modifications of the effect of radiation on tumor and normal cells. This chapter presents objectives for identifying naturally occurring substances that modify the effect of x-radiation on mammalian cells and discusses the role of physiologic substances in modifying radiation injuries on mammalian normal and tumor cells

  20. Radiation damage in proton-irradiated epitaxial silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Lange, Joern

    2009-07-15

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

  1. Radiation damage in proton-irradiated epitaxial silicon detectors

    International Nuclear Information System (INIS)

    Lange, Joern

    2009-07-01

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

  2. Vasculotide, an Angiopoietin-1 mimetic, reduces acute skin ionizing radiation damage in a preclinical mouse model.

    Science.gov (United States)

    Korpela, Elina; Yohan, Darren; Chin, Lee Cl; Kim, Anthony; Huang, Xiaoyong; Sade, Shachar; Van Slyke, Paul; Dumont, Daniel J; Liu, Stanley K

    2014-08-26

    Most cancer patients are treated with radiotherapy, but the treatment can also damage the surrounding normal tissue. Acute skin damage from cancer radiotherapy diminishes patients' quality of life, yet effective biological interventions for this damage are lacking. Protecting microvascular endothelial cells from irradiation-induced perturbations is emerging as a targeted damage-reduction strategy. Since Angiopoetin-1 signaling through the Tie2 receptor on endothelial cells opposes microvascular perturbations in other disease contexts, we used a preclinical Angiopoietin-1 mimic called Vasculotide to investigate its effect on skin radiation toxicity using a preclinical model. Athymic mice were treated intraperitoneally with saline or Vasculotide and their flank skin was irradiated with a single large dose of ionizing radiation. Acute cutaneous damage and wound healing were evaluated by clinical skin grading, histology and immunostaining. Diffuse reflectance optical spectroscopy, myeloperoxidase-dependent bioluminescence imaging of neutrophils and a serum cytokine array were used to assess inflammation. Microvascular endothelial cell response to radiation was tested with in vitro clonogenic and Matrigel tubule formation assays. Tumour xenograft growth delay experiments were also performed. Appreciable differences between treatment groups were assessed mainly using parametric and non-parametric statistical tests comparing areas under curves, followed by post-hoc comparisons. In vivo, different schedules of Vasculotide treatment reduced the size of the irradiation-induced wound. Although skin damage scores remained similar on individual days, Vasculotide administered post irradiation resulted in less skin damage overall. Vasculotide alleviated irradiation-induced inflammation in the form of reduced levels of oxygenated hemoglobin, myeloperoxidase bioluminescence and chemokine MIP-2. Surprisingly, Vasculotide-treated animals also had higher microvascular endothelial cell

  3. Conformational variation of proteins at room temperature is not dominated by radiation damage

    International Nuclear Information System (INIS)

    Russi, Silvia; González, Ana; Kenner, Lillian R.; Keedy, Daniel A.; Fraser, James S.; Bedem, Henry van den

    2017-01-01

    Protein crystallography data collection at synchrotrons is routinely carried out at cryogenic temperatures to mitigate radiation damage. Although damage still takes place at 100 K and below, the immobilization of free radicals increases the lifetime of the crystals by approximately 100-fold. Recent studies have shown that flash-cooling decreases the heterogeneity of the conformational ensemble and can hide important functional mechanisms from observation. These discoveries have motivated increasing numbers of experiments to be carried out at room temperature. However, the trade-offs between increased risk of radiation damage and increased observation of alternative conformations at room temperature relative to cryogenic temperature have not been examined. A considerable amount of effort has previously been spent studying radiation damage at cryo-temperatures, but the relevance of these studies to room temperature diffraction is not well understood. Here, the effects of radiation damage on the conformational landscapes of three different proteins (T. danielli thaumatin, hen egg-white lysozyme and human cyclophilin A) at room (278 K) and cryogenic (100 K) temperatures are investigated. Increasingly damaged datasets were collected at each temperature, up to a maximum dose of the order of 10 7 Gy at 100 K and 10 5 Gy at 278 K. Although it was not possible to discern a clear trend between damage and multiple conformations at either temperature, it was observed that disorder, monitored by B-factor-dependent crystallographic order parameters, increased with higher absorbed dose for the three proteins at 100 K. At 278 K, however, the total increase in this disorder was only statistically significant for thaumatin. A correlation between specific radiation damage affecting side chains and the amount of disorder was not observed. Lastly, this analysis suggests that elevated conformational heterogeneity in crystal structures at room temperature is observed despite radiation

  4. Gallium Arsenide solar cell radiation damage experiment

    Science.gov (United States)

    Maurer, R. H.; Kinnison, J. D.; Herbert, G. A.; Meulenberg, A.

    1991-01-01

    Gallium arsenide (GaAs) solar cells for space applications from three different manufactures were irradiated with 10 MeV protons or 1 MeV electrons. The electrical performance of the cells was measured at several fluence levels and compared. Silicon cells were included for reference and comparison. All the GaAs cell types performed similarly throughout the testing and showed a 36 to 56 percent power areal density advantage over the silicon cells. Thinner (8-mil versus 12-mil) GaAs cells provide a significant weight reduction. The use of germanium (Ge) substrates to improve mechanical integrity can be implemented with little impact on end of life performance in a radiation environment.

  5. Transesophageal Echocardiography and Radiation-induced Damages.

    Science.gov (United States)

    Cottini, Marzia; Polizzi, Vincenzo; Pino, Paolo Giuseppe; Buffa, Vitaliano; Musumeci, Francesco

    2016-01-01

    The long-term sequelae of mantle therapy include, especially lung and cardiac disease but also involve the vessels and the organs in the neck and thorax (such as thyroid, aorta, and esophagus). We presented the case of 66-year-old female admitted for congestive heart failure in radiation-induced heart disease. The patient had undergone to massive radiotherapy 42 years ago for Hodgkin's disease (type 1A). Transesophageal echocardiography was performed unsuccessfully with difficulty because of the rigidity and impedance of esophageal walls. Our case is an extraordinary report of radiotherapy's latency effect as a result of dramatic changes in the structure of mediastinum, in particular in the esophagus, causing unavailability of a transesophageal echocardiogram.

  6. Radiation damage in carbon-carbon composites

    International Nuclear Information System (INIS)

    Burchell, T.D.; Eartherly, W.P.; Nelson, G.E.

    1992-01-01

    Graphite and carbon-carbon composite materials are widely used in plasma facing applications in current Tokamak devices such as TFTR and DIIID in the USA, JET, Tore Supra and TEXTOR in Europe, and JT-60U in Japan. Carbon-carbon composites are attractive choices for Tokamak limiters and diverters because of their low atomic number, high thermal shock resistance, high melting point, and high thermal conductivity. Next generation machines such as the International Thermonuclear Experimental Reactor (ITER) will utilize carbon-carbon composites in their first wall and diverter. ITER will be an ignition machine and thus will produce substantial neutron fluences from the D-T fusion reaction. The resultant high energy neutrons will cause carbon atom displacements in the plasma facing materials which will markedly affect their structure and physical properties. The effect of neutron damage on graphite has been studied for over forty years. Recently the effects of neutron irradiation on the fusion relevant graphite GraphNOL N3M was reviewed. In contrast to graphite, relatively little work has been performed to elucidate the effects of neutron irradiation on carbon-carbon composites. The results of our previous irradiation experiments have been published elsewhere. Here the irradiation induced dimensional changes in 1D, 2D, and 3D carbon-carbon composites are reported for fluences up to 4.7 dpa at an irradiation temperature of 600 degree C

  7. Effect of superposed electromagnetic noise on DNA damage of lens epithelial cells induced by microwave radiation.

    Science.gov (United States)

    Yao, Ke; Wu, Wei; Yu, Yibo; Zeng, Qunli; He, Jiliang; Lu, Deqiang; Wang, Kaijun

    2008-05-01

    To investigate the influence of the 1.8-GHz radiofrequency fields (RFs) of the Global System for Mobile Communications on DNA damage, intracellular reactive oxygen species (ROS) formation, cell cycle, and apoptosis in human lens epithelial cells (hLECs) and whether the effects induced by RF could be blocked by superposing of electromagnetic noise. After 24-hour intermittent exposure at the specific absorption rate of 1 W/kg, 2 W/kg, 3 W/kg, and 4 W/kg, the DNA damage of hLECs was examined by alkaline comet assay and immunofluorescence microscope detection of the phosphorylated form of histone variant H2AX (gammaH2AX) foci, respectively. ROS production was quantified by the fluorescent probe 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA). Cell cycle and cell apoptosis were determined by flow cytometry. DNA damage examined by alkaline comet assay was significantly increased after 3 W/kg and 4 W/kg radiation (P radiation (P microwave radiation and sham exposure groups (P > 0.05). All the effects mentioned were blocked when the RF was superposed with 2 muT electromagnetic noise. Microwave radiation induced hLEC DNA damage after G(0)/G(1) arrest does not lead to cell apoptosis. The increased ROS observed may be associated with DNA damage. Superposed electromagnetic noise blocks microwave radiation-induced DNA damage, ROS formation, and cell cycle arrest.

  8. LHCb: Radiation Damage in the LHCb VELO

    CERN Multimedia

    Rodriguez Perez, P

    2012-01-01

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

  9. Genomic damage in children accidentally exposed to ionizing radiation

    DEFF Research Database (Denmark)

    Fucic, A; Brunborg, G; Lasan, R

    2007-01-01

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

  10. Fluorescence studies on radiation oxidative damage to membranes ...

    Indian Academy of Sciences (India)

    Changes in the lipid bilayer in irradiated unilamellar liposomes prepared from egg yolk lecithin (EYL) were measured by using diphenylhexatriene (DPH) as a probe. ... Inclusion of cholesterol in liposome was found to protect lipids against radiation damage, possibly by modulation of bilayer organization e.g. lipid packing.

  11. Effect of Rosiglitazone on Radiation Damage in Bone Marrow Hemopoiesis

    Science.gov (United States)

    Benkő, Klára; Pintye, Éva; Szabó, Boglárka; Géresi, Krisztina; Megyeri, Attila; Benkő, Ilona

    2008-12-01

    To study radiobiological effects and drugs, which can modify radiation injury, has an importance if we would like to avoid harmful effects of radiation due to emergency situations or treat patients with malignant diseases by radiotherapy. During the long treatment schedules patients may be treated by not only anticancer but many other drugs because of accompanying diseases. These drugs may also modify radiobiological effects. Rosiglitazone pre-treatment proved to be myeloprotective and accelerated recovery of 5-fluorouracil-damaged bone marrow in our previous experiments. Our new studies are designed to evaluate whether rosiglitazone has similar beneficial effects in radiation-damaged hemopoiesis. Bone marrow damage was precipitated by total body irradiation (TBI) using single increasing doses (2-10 Gy) of γ—irradiation in groups of mice. Lethality was well correlated with damage in hemopoiesis measured by cellularity of bone marrow (LD50 values were 4.8 and 5.3 gray respectively). Rosiglitazone, an insulin-sensitizing drug, had no significant effect on bone marrow cellularity. Insulin resistance associated with obesity or diabetes mellitus type 2 is intensively growing among cancer patients requiring some kind of radiotherapy. Therefore it is important to know whether drugs used for their therapy can modify radiation effects.

  12. Radiation damage measurements on CZT drift strip detectors

    DEFF Research Database (Denmark)

    Kuvvetli, Irfan; Budtz-Jørgensen, Carl; Korsbech, Uffe C C

    2003-01-01

    from 2 x 10(8) to 60 x 10(8) p(+)/cm(2). Even for the highest fluences, which had a dramatic effect on the spectroscopic performance, we were able to recover the detectors after an appropriate annealing procedure. The radiation damage was studied as a function of depth inside the detector material...

  13. Ion bombardment simulation: a review related to fusion radiation damage

    International Nuclear Information System (INIS)

    Brimhall, J.L.

    1975-01-01

    Prime emphasis is given to reviewing the ion bombardment data on the refractory metals molybdenum, niobium and vanadium which have been proposed for use in advanced fusion devices. The temperature and dose dependence of the void parameters are correlated among these metals. The effect of helium and hydrogen gas on the void parameters is also included. The similarities and differences of the response of these materials to high dose, high temperature radiation damage are evaluated. Comparisons are made with results obtained from stainless steel and nickel base alloys. The ion bombardment data is then compared and correlated, as far as possible, with existing neutron data on the refractory metals. The theoretically calculated damage state produced by neutrons and ions is also briefly discussed and compared to experimental data wherever possible. The advantages and limitations of ion simulation in relation to fusion radiation damage are finally summarized

  14. Mechanisms for radiation damage in DNA. Progress report, June 1, 1993--May 31, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Sevilla, M.D.

    1993-12-01

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

  15. Temperature effects on radiation damage in plastic detectors

    International Nuclear Information System (INIS)

    Mendoza A, D.

    1996-01-01

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

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

    International Nuclear Information System (INIS)

    Beynel, P.; Maier, P.; Schoenbacher, H.

    1982-01-01

    This handbook gives the results of radiation damage tests on various engineering materials and components intended for installation in radiation areas of the CERN high-energy particle accelerators. It complements two previous volumes covering organic cable-insulating materials and thermoplastic and thermosetting resins. The irradiation have been carried out at various radiation sources and the results of the different tests are reported, sometimes illustrated by tables and graphs to show the variation of the measured property with absorbed radiation dose. For each entry, an appreciation of the radiation resistance is given, based on measurement data, indicating the range of damage (moderate to severe) for doses from 10 to 10 8 Gy. Also included are tables, selected from published reports, of general relative radiation effects for several groups of materials, to which there are systematic cross-references in the alphabetical part. This third and last volume contains cross-references to all the materials presented up to now, so that it can be used as a guide to the three volumes. (orig.)

  17. Radiation damage and annealing in plutonium tetrafluoride

    Energy Technology Data Exchange (ETDEWEB)

    McCoy, Kaylyn; Casella, Amanda; Sinkov, Sergey; Sweet, Lucas; McNamara, Bruce; Delegard, Calvin; Jevremovic, Tatjana

    2017-12-01

    Plutonium tetrafluoride that was separated prior to 1966 at the Hanford Site in Washington State was analyzed at the Pacific Northwest National Laboratory (PNNL) in 2015 and 2016. The plutonium tetrafluoride, as received, was an off-normal color and considering the age of the plutonium, there were questions about the condition of the material. These questions had to be answered in order to determine the suitability of the material for future use or long-term storage. Therefore, Thermogravimetric/Differential Thermal Analysis and X-ray Diffraction evaluations were conducted to determine the plutonium’s crystal structure, oxide content, and moisture content; these analyses reported that the plutonium was predominately amorphous and tetrafluoride, with an oxide content near ten percent. Freshly fluorinated plutonium tetrafluoride is known to be monoclinic. During the initial Thermogravimetric/Differential Thermal analyses, it was discovered that an exothermic event occurred within the material near 414°C. X-ray Diffraction analyses were conducted on the annealed tetrafluoride. The X-ray Diffraction analyses indicated that some degree of recrystallization occurred in conjunction with the 414°C event. The following commentary describes the series of Thermogravimetric/Differential Thermal and X-ray Diffraction analyses that were conducted as part of this investigation at PNNL, in collaboration with the University of Utah Nuclear Engineering Program.

  18. Radiation-induced Pulmonary Damage in Lung Cancer Patients

    International Nuclear Information System (INIS)

    Chung, Su Mi; Choi, Ihl Bohng; Kang, Mi Mun; Kim, In Ah; Shinn, Kyung Sub

    1993-01-01

    Purpose: A retrospective analysis was performed to evaluate the incidence of radiation induced lung damage after the radiation therapy for the patients with carcinoma of the lung. Method and Materials: Sixty-six patients with lung cancer (squamous cell carcinoma 27, adenocarcinoma 14, large cell carcinoma 2, small cell carcinoma 13, unknown 10) were treated with definitive, postoperative or palliative radiation therapy with or without chemotherapy between July 1987 and December 1991. There were 50 males and 16 females with median age of 63 years(range: 33-80 years). Total lung doses ranged from 500 to 6,660 cGy (median 3960 cGy) given in 2 to 38 fractions (median 20) over a range of 2 to 150 days (median 40 days) using 6 MV or 15 MV linear accelerator. To represent different fractionation schedules of equivalent biological effect, the estimated single dose(ED) model, ED=D·N-0.377·T-0.058 was used in which D was the lung dose in cGy, N was the number of fractions, and T was the overall treatment time in days. The range of ED was 370 to 1357. The endpoint was a visible increase in lung density within the irradiated volume on chest X-ray as observed independently by three diagnostic radiologists. Patients were grouped according to ED, treatment duration, treatment modality and age, and the percent incidence of pulmonary damage for each group was determined. Result: In 40 of 66 patients, radiation induced change was seen on chest radiographs between 11 days and 314 days after initiation of radiation therapy. The incidence of radiation pneumonitis was increased according to increased ED, which was statistically significant (p=0.001). Roentgenographic charges consistent with radiation pneumonitis were seen in 100% of patients receiving radiotherapy after lobectomy or pneumonectomy, which was not statistically significant. In 32 patients who also received chemotherapy, there was no difference in the incidence of radiation induced charge between the group with radiation

  19. Radiation damage response of ceramics in extreme environments

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-10-15

    Oxide-based and inter-metallic compounds have great potential as new materials for clean and renewable energy production. Many of these materials, especially those designed for operation in Generation IV fission reactors or in fusion reactors, must exhibit robust performance under extreme conditions of temperature, irradiation, and chemical attack. Others, such as nuclear waste forms, may be required to retain radioactive elements for long periods of time in geological repositories. The mechanisms of radiation damage production and recovery in these materials may vary considerably as a function of the damage source, e.g., energetic neutrons in reactor systems versus alpha decay in nuclear waste forms. Furthermore, the kinetics of damage recovery are complicated by multiply activated processes and in certain cases, longer-term diffusion may modify the structural state left by irradiation in the short term. Here, we review some basic concepts regarding the mechanisms of radiation damage in selected ceramic materials, including mathematical models, fluence-temperature relationships, and predictive methodologies. A major consideration for materials performance is the ability of a given compound to resist amorphization. Historically, there are a number of general criteria for radiation resistance, including those involving melting point (thermodynamics), structural freedom, bonding, and energetics of defect formation. These are discussed using specific examples. (Author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-11-22

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

  1. Laser annealing heals radiation damage in avalanche photodiodes

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-12-15

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

  2. Radiation damage in CaF2: Gd

    International Nuclear Information System (INIS)

    Prado, L.

    1979-01-01

    Calcium fluoride crystals doped with Gd 3+ at four different concentrations were irradiated at room temperature. The damage produced by radiation and the primary and secondary effects as well were studied by optical spectroscopy. The increase in optical absorption (with loss of transparency) varied from sample as a function of concentration and dose. The coloration curves showed an evolution from two to three radiation damage steps when going from a pure to the most Gd 3+ concentrated sample. The obtained spectra were analysed at characteristic wave lenghts of electronic defects (photochromic centers, F and its aggregates) and of Gd 3+ and Gd 2+ defects. As a result of the radiation damage the valence change (Gd 3+ →Gd 2+ ) and its reversible character under thermal activation were directly observed. These effects were correlated with other observed effects such as the room temperature luminescence after the irradiation ceased. The non radiative F centers formation from the interaction of holes and photochromic centers was also observed and analysed. A thermal activation study of the several defects responsible for the different absorption bands was made. Values of activation energies were obtained as expected for the kind of defects involved in these processes [pt

  3. Monitoring Radiation Damage in the ATLAS Pixel Detector

    CERN Document Server

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

    2014-11-05

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

  4. Radiation damage in boron nitride x-ray lithography masks

    International Nuclear Information System (INIS)

    King, P.L.; Pan, L.; Pianetta, P.; Shimkunas, A.; Mauger, P.; Seligson, D.

    1988-01-01

    The optical and mechanical properties of boron nitride vapor deposited at 400 0 C are shown to degrade when exposed to synchrotron radiation. The extent of the damage and the rate at which the damage occurs are similar to that first reported by Johnson et al. Transmission through membranes of boron nitride was measured in situ during exposure to x rays. Membranes darkened considerably with the transmission through a typical membrane falling from 50% to 20% after absorbing ∼250 kJ/cm 3 of x rays. Changes in local film stress were measured with a simple cantilever technique. Films originally in tension (∼5E8 dyne/cm 2 ) were found to become compressive after absorbing 300 kJ/cm 3 of x rays. Both forms of damage responded well to annealing. Fourier transform infrared (FTIR) and near-edge x-ray absorption measurements were made to discern the structural differences between degraded and unexposed films. No significant structural changes were observed. Boron nitride films deposited at higher temperatures (600 0 C) proved to be much less susceptible to radiation damage. In a related development, films produced through the pyrolysis of borazine appeared to be completely immune to radiation damage as were silicon and silicon nitride membranes. FTIR spectra indicate that less hydrogen is present in the 600 0 C chemical-vapor deposition (CVD) and the pyrolytic boron nitride films than in the 400 0 C CVD films. As proposed by Johnson et al., hydrogen is implicated as an intermediary in the boron nitride damage mechanism

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-04-01

    Zircons are a well-known candidate waste form for actinides and their radiation damage behaviour has been widely studied by a range of techniques. In this study, well-characterised natural single crystal zircons have been studied using Positron Annihilation Lifetime Spectroscopy (PALS). In some, but not all, of the crystals that had incurred at least half of the alpha-event damage of ∼10{sup 19} α/g required to render them structurally amorphous, PALS spectra displayed long lifetimes corresponding to voids of ∼0.5 nm in diameter. The long lifetimes corresponded to expectations from published Small-Angle X-ray Scattering data on similar samples. However, the non-observation by PALS of such voids in some of the heavily damaged samples may reflect large size variations among the voids such that no singular size can be distinguished or. Characterisation of a range of samples was also performed using scanning electron microscopy, optical absorption spectroscopy, Raman scattering and X-ray scattering/diffraction, with the degree of alpha damage being inferred mainly from the Raman technique and X-ray diffraction. The observed void diameters and intensities of the long lifetime components were changed somewhat by annealing at 700 °C; annealing at 1200 °C removed the voids entirely. The voids themselves may derive from He gas bubbles or voids created by the inclusion of small quantities of organic and hydrous matter, notwithstanding the observation that no voidage was evidenced by PALS in two samples containing hydrous and organic matter. - Highlights: • Study of a range of naturally occurring zircons damaged by alpha radiation. • Characterised using a range of techniques, including PALS spectroscopy. • Effects on hydrous material appear important, rather than direct radiation damage. • Annealing is shown to remove the observed voids.

  6. Primary radiation damage and disturbance in cell divisions

    International Nuclear Information System (INIS)

    Kim, Jin Kyu; Lee, Yun-Jong; Kim, Jae-Hun; Petin, Vladislav G.; Nili, Mohammad

    2008-01-01

    Survived cells from a homogeneous population exposed to ionizing radiation form various colonies of different sizes and morphology on a solid nutrient medium, which appear at different time intervals after irradiation. Such a phenomenon agrees well with the modern theory of microdosimetry and classical hit-and-target models of radiobiology. According to the hit-principle, individual cells exposed to the same dose of radiation are damaged in different manners. It means that the survived cells can differ in the content of sublethal damage (hits) produced by the energy absorbed into the cell and which is not enough to give rise to effective radiation damage which is responsible for cell killing or inactivation. In diploid yeast cells, the growth rate of cells from 250 colonies of various sizes appeared at different time intervals after irradiation with 600 Gy of gamma radiation from a 60 Co isotopic source was analyzed. The survival rate after irradiation was 20%. Based on the analyses results, it was possible to categorize the clones grown from irradiated cells according to the number of sub-lesions from 1 to 4. The clones with various numbers of sub-lesions were shown to be different in their viability, radiosensitivity, sensitivity to environmental conditions, and the frequency of recombination and respiratory deficient mutations. Cells from unstable clones exhibited an enhanced radiosensitivity, and an increased portion of morphologically changed cells, nonviable cells and respiration mutants, as well. The degree of expression of the foregoing effects was higher if the number of primary sublethal lesions was greater in the originally irradiated cell. Disturbance in cell division can be characterized by cell inactivation or incorrect distribution of mitochondria between daughter cells. Thus, the suggested methodology of identification of cells with a definite number of primary sublethal lesions will promote further elucidation of the nature of primary radiation

  7. A Combination of Pre- and Post-Exposure Ascorbic Acid Rescues Mice from Radiation-Induced Lethal Gastrointestinal Damage

    Science.gov (United States)

    Ito, Yasutoshi; Kinoshita, Manabu; Yamamoto, Tetsuo; Sato, Tomohito; Obara, Takeyuki; Saitoh, Daizoh; Seki, Shuhji; Takahashi, Yukihiro

    2013-01-01

    The development of an effective therapy for radiation-induced gastrointestinal damage is important, because it is currently a major complication of treatment and there are few effective therapies available. Although we have recently demonstrated that pretreatment with ascorbic acid attenuates lethal gastrointestinal damage in irradiated mice, more than half of mice eventually died, thus indicating that better approach was needed. We then investigated a more effective therapy for radiation-induced gastrointestinal damage. Mice receiving abdominal radiation at 13 Gy were orally administered ascorbic acid (250 mg/kg/day) for three days before radiation (pretreatment), one shot of engulfment (250 mg/kg) at 8 h before radiation, or were administered the agent for seven days after radiation (post-treatment). None of the control mice survived the abdominal radiation at 13 Gy due to severe gastrointestinal damage (without bone marrow damage). Neither pretreatment with ascorbic acid (20% survival), engulfment (20%), nor post-treatment (0%) was effective in irradiated mice. However, combination therapy using ascorbic acid, including pretreatment, engulfment and post-treatment, rescued all of the mice from lethal abdominal radiation, and was accompanied by remarkable improvements in the gastrointestinal damage (100% survival). Omitting post-treatment from the combination therapy with ascorbic acid markedly reduced the mouse survival (20% survival), suggesting the importance of post-treatment with ascorbic acid. Combination therapy with ascorbic acid may be a potent therapeutic tool for radiation-induced gastrointestinal damage. PMID:24084715

  8. Radiation damage formation in fusion structural materials due to elastic and inelastic processes

    Science.gov (United States)

    Ryazanov, A. I.; Semenov, E. V.

    2011-10-01

    A new theoretical model based on Boltzmann transport equation for moving displaced atoms is developed for the investigations of main important characteristics of radiation damage production in fusion structural materials. The main characteristics sub-cascades are determined here including the distribution of sub-cascades per PKA, average number of point defects per sub-cascade combining suggested model and NRT approach, sub-cascade's cross-sections and generation rates for both elastic and inelastic processes. On the basis of this developed model the numerical calculations for the main important characteristics of radiation damage production, cascade and sub-cascade formations in different fusion structural materials such as Fe, V, C, Al, Be and W are performed using the neutron energy spectra for fusion reactors: ITER and DEMO. For the comparison of difference in radiation damage production in fusion and fission reactors the additional numerical calculations have been made for neutron energy spectrum in fast atomic reactor HFIR.

  9. Investigating Undergraduate Students’ Conceptions of Radiation

    Science.gov (United States)

    Romine, James M.; Buxner, Sanlyn; Impey, Chris; Nieberding, Megan; Antonellis, Jessie C.

    2014-11-01

    Radiation is an essential topic to the physical sciences yet is often misunderstood by the general public. The last time most people have formal instruction about radiation is as students in high school and this knowledge will be carried into adulthood. Peoples’ conceptions of radiation influence their attitude towards research regarding radiation, radioactivity, and other work where radiation is prevalent. In order to understand students’ ideas about radiation after having left high school, we collected science surveys from nearly 12,000 undergraduates enrolled in introductory science courses over a span of 25 years. This research investigates the relationship between students’ conceptions of radiation and students’ personal beliefs and academic field of study.Our results show that many students in the sample were unable to adequately describe radiation. Responses were typically vague, brief, and emotionally driven. Students’ field of study was found to significantly correlate with their conceptions. Students pursuing STEM majors were 60% more likely to describe radiation as an emission and/or form of energy and cited atomic or radioactive sources of radiation twice as often as non-STEM students. Additionally, students’ personal beliefs also appear to relate to their conceptions of radiation. The most prominent misconception shown was that radiation is a generically harmful substance, which was found to be consistent throughout the duration of the study. In particular, non-science majors in our sample had higher rates of misconceptions, often generalized the idea of radiation into a broad singular topic, and had difficulty properly identifying sources.Generalized ideas of radiation and the inability to properly recognize sources of radiation may contribute to the prevalent misconception that radiation is an inexplicably dangerous substance. A basic understanding of both electromagnetic and particulate radiation and the existence of radiation at various

  10. Study of radiation damage in metals by positron annihilation

    International Nuclear Information System (INIS)

    Gauster, W.B.

    1977-01-01

    Positron annihilation is a sensitive technique for probing defects in metals and it has recently been shown to be a valuable tool for the study of radiation damage. After an introduction to the three basic experimental methods (angular correlation, Doppler broadening, and lifetime measurements), the interaction of positrons with lattice defects is reviewed. Results for the annealing of damage after low temperature irradiation are used to show that positron annihilation has provided new information on annealing kinetics. The role of positron techniques in characterizing complex defect structures resulting from high-temperature neutron irradiation is reviewed and the possible utility of positron annihilation as a nondestructive monitor of property changes is pointed out

  11. Genetic damage from low-level and natural background radiation

    International Nuclear Information System (INIS)

    Oftedal, P.

    1988-01-01

    Relevant predictions that have been made of possible low level biological effects on man are reviewed, and the estimate of genetic damage is discussed. It is concluded that in spite of a number of attempts, no clear-cut case of effects in human populations of radiation at natural levels has been demonstrated. The stability of genetic material is dynamic, with damage, repair and selection running as continuous processes. Genetic materials are well protected and are conservative in the extreme, not least because evolution by genetic adaptation is an expensive process: Substitution of one allele A 1 by another A 2 means the death of the whole A 1 population

  12. Development and anneal of radiation damage in salt

    International Nuclear Information System (INIS)

    Garcia Celma, A.; Donker, H.; Soppe, W.J.; Miralles, L.

    1993-12-01

    Laboratory gamma-irradiations at a constant temperature (100 C) were carried out in two sorts of experiments, one at variable and another at approximately constant dose rates. The damage developed during irradiation was analyzed by thermal analysis, microstructural analysis and small angle neutron scattering. The results were compared with the yields of the Jain-Lidiard model for each experiment. Experiments at a constant dose rate were planned to obtain information on radiation damage development and anneal in conditions as near as possible to those of radioactive waste repository concepts. For this reason the dose rates were kept low. (orig./DG)

  13. Measuring Radiation Damage from Heavy Energetic Ions in Aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Kostin, M., PI-MSU; Ronningen, R., PI-MSU; Ahle, L., PI-LLNL; Gabriel, T., Scientific Investigation and Development; Mansur, L., PI-ORNL; Leonard, K., ORNL; Mokhov, N., FNAL; Niita, K., RIST, Japan

    2009-02-21

    An intense beam of 122 MeV/u (9.3 GeV) 76Ge ions was stopped in aluminum samples at the Coupled Cyclotron Facility at NSCL, MSU. Attempts were made at ORNL to measure changes in material properties by measuring changes in electrical resistivity and microhardness, and by transmission electron microscopy characterization, for defect density caused by radiation damage, as a function of depth and integrated ion flux. These measurements are relevant for estimating damage to components at a rare isotope beam facility.

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

    International Nuclear Information System (INIS)

    Jayakumar, S.; Bhilwade, H.N.; Chaubey, R.C.

    2012-01-01

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

  15. Modification of radiation-induced oxidative damage in liposomal and microsomal membrane by eugenol

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, B.N. [Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Lathika, K.M. [Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Mishra, K.P. [Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)]. E-mail: kpm@magnum.barc.ernet.in

    2006-03-15

    Radiation-induced membrane oxidative damage, and their modification by eugenol, a natural antioxidant, was investigated in liposomes and microsomes. Liposomes prepared with DPH showed decrease in fluorescence after {gamma}-irradiation, which was prevented significantly by eugenol and correlated with magnitude of oxidation of phospholipids. Presence of eugenol resulted in substantial inhibition in MDA formation in irradiated liposomes/microsomes, which was less effective when added after irradiation. Similarly, the increase in phospholipase C activity observed after irradiation in microsomes was inhibited in samples pre-treated with eugenol. Results suggest association of radio- oxidative membrane damage with alterations in signaling molecules, and eugenol significantly prevented these membrane damaging events.

  16. Prediction of radiation-related small-bowel damage

    International Nuclear Information System (INIS)

    Potish, R.A.

    1980-01-01

    In order to predict which patients have a high risk for radiation-related small-bowel damage, the concept of the dose-response curve was applied to the predisposing factors (number of previous laparotomies, extent of surgery, thin physique, hypertension, age, cancer stage, number of treatment days, fractionation, and weight change during radiotherapy) present in 92 patients receiving identical radiation doses and volumes This analysis allows an estimate of the probability of complication to be assigned to individual patients. The utility and limitations of the dose-response concept are discussed

  17. Radiation damage studies of detector-compatible Si JFETs

    Energy Technology Data Exchange (ETDEWEB)

    Dalla Betta, Gian-Franco [INFN, Sezione di Padova (Gruppo Collegato di Trento), and Dipartimento di Informatica e Telecomunicazioni, Universita di Trento, Via Sommarive, 14, I-38050 Povo di Trento (Italy)]. E-mail: dallabe@dit.unitn.it; Boscardin, Maurizio [ITC-irst, Divisione Microsistemi, I-38050 Povo di Trento, Via Sommarive, 18, 38050 Povo di Trento (Italy); Candelori, Andrea [INFN, Sezione di Padova, Via Marzolo, 8, I-35131 Padova (Italy); Pancheri, Lucio [INFN, Sezione di Padova (Gruppo Collegato di Trento), and Dipartimento di Informatica e Telecomunicazioni, Universita di Trento, Via Sommarive, 14, I-38050 Povo di Trento (Italy); Piemonte, Claudio [ITC-irst, Divisione Microsistemi, I-38050 Povo di Trento, Via Sommarive, 18, 38050 Povo di Trento (Italy); Ratti, Lodovico [INFN, Sezione di Pavia, and Dipartimento di Elettronica, Universita di Pavia, Via Ferrata 1, I-27100 Pavia (Italy); Zorzi, Nicola [ITC-irst, Divisione Microsistemi, I-38050 Povo di Trento, Via Sommarive, 18, 38050 Povo di Trento (Italy)

    2007-03-01

    We have largely improved the performance of our detector-compatible Si JFETs by optimizing the fabrication technology. New devices feature thermal noise values close to the theoretical ones, and remarkably low 1/f noise figures. In view of adopting these JFETs for X-ray imaging and HEP applications, bulk and surface radiation damage tests have been carried out by irradiating single transistors and test structures with neutrons and X-rays. Selected results from static and noise characterization of irradiated devices are discussed in this paper, and the impact of radiation effects on the performance of JFET-based circuits is addressed.

  18. Radiation damage and induced tetraploidy in mulberry (Morus alba L.)

    International Nuclear Information System (INIS)

    Katagiri, K.

    1976-01-01

    Vigorously growing mulberry shoots were exposed to 5 kR of gamma rays at the rate of 0.2 kR/hr and 5.0 kR/hr and successively pruned three times in two growing seasons. The most radiosensitive part of both the apical and axillary meristems was the second cell layer. The younger axillary bud primordia were more sensitive to radiation then the older ones. Recovery from radiation damage was assumed to be from the flank meristem in the shoot apex. The frequency of mutations was much lower than that of tetraploidy. Among the tetraploids 50% were 2-4-4 chimeras. (author)

  19. Radiation damage studies of detector-compatible Si JFETs

    International Nuclear Information System (INIS)

    Dalla Betta, Gian-Franco; Boscardin, Maurizio; Candelori, Andrea; Pancheri, Lucio; Piemonte, Claudio; Ratti, Lodovico; Zorzi, Nicola

    2007-01-01

    We have largely improved the performance of our detector-compatible Si JFETs by optimizing the fabrication technology. New devices feature thermal noise values close to the theoretical ones, and remarkably low 1/f noise figures. In view of adopting these JFETs for X-ray imaging and HEP applications, bulk and surface radiation damage tests have been carried out by irradiating single transistors and test structures with neutrons and X-rays. Selected results from static and noise characterization of irradiated devices are discussed in this paper, and the impact of radiation effects on the performance of JFET-based circuits is addressed

  20. [Cellphone electromagnetic radiation damages the testicular ultrastructure of male rats].

    Science.gov (United States)

    Gao, Xiao-Hui; Hu, Hui-Rong; Ma, Xue-Lian; Chen, Jie; Zhang, Guo-Hong

    2016-06-01

    To investigate the influence of cellphone electromagnetic radiation (CER) on the testicular ultrastructure and the apoptosis of spermatogenic cells in male rats.atability, feasibility, applicability, and controllability in the construction of experimental animal models, we compared the major anatomic features of the penis of 20 adult beagle dogs with those of 10 adult men. Using microsurgical techniques, we performed cross-transplantation of the penis in the 20 (10 pairs) beagle dogs and observed the survival rate of the transplanted penises by FK506+MMF+MP immune induction. We compared the relevant indexes with those of the 10 cases of microsurgical replantation of the amputated penis. Thirty adult male SD rats were equally randomized into a 2 h CER, a 4 h CER, and a normal control group, the former two groups exposed to 30 days of 900 MHz CER for 2 and 4 hours a day, respectively, while the latter left untreated. Then the changes in the ultrastructure of the testis tissue were observed under the transmission electron microscope and the apoptosis of the spermatogenic cells was determined by TUNEL. Compared with the normal controls, the rats of the 2 h CER group showed swollen basement membrane of seminiferous tubules, separated tight junction of Sertoli cells, increased cell intervals, apparent vacuoles and medullization in some mitochondria, and increased apoptosis of spermatogenic cells, mainly the apoptosis of primary spermatocytes (P<0.05 ). In comparison with the 2 h CER group, the animals of the 4 h CER group exhibited swollen basement membrane of seminiferous tubules, more separated tight junction of Sertoli cells, wider cell intervals, incomplete membrane of spermatogonial cells, fragments of cytoplasm, nuclear pyknosis and notch, slight dilation of perinuclear space, abnormalities of intracellular mitochondria with vacuoles, fuzzy structure, and fusion or disappearance of some cristae, and increased damage of mitochondria and apoptosis of spermatogenic

  1. Quantum theory of radiation interaction with the crystals containing radiation damages

    International Nuclear Information System (INIS)

    Kirilyuk, A.P.; Molodkin, V.B.; Novitskij, V.G.; Osinovskij, M.E.

    1983-01-01

    Quantum theory of radiation interaction (charged particles, neutrons etc.) with crystals containing random distributed radiation defects of varioUs type is given. In the frames of this theory the study of the orientation dependence of the effects of suppression of futher formation of radiation defects and some other interaction processes of radiation interaction with a solids is carried on. The criteria of the proposed consideration of the application is analysed. A principle possibility of an aimed interaction on the processes of radiation damage allowing to change up to an order their magnitude and the depth of radiation penetrating into a crystal is shown and studied in details. New nuclear-physical highly-responsed crystal structural method of experimental study of radiation defects characteristics are based on the theoretical results of coherent effects of radiation scattering in those crystals

  2. Intensification of ultraviolet-induced dermal damage by infrared radiation

    International Nuclear Information System (INIS)

    Kligman, L.H.

    1982-01-01

    To assess the role of IR in actinic damage to the dermis, albino guinea pigs were irradiated for 45 weeks with UV-B and UV-A, with and without IR. Control animals received IR only or no irradiation at all. Unirradiated dermis contains small amounts of elastic fibers in the upper dermis with greater depositions around follicles and sebaceous glands. After irradiation with UV, the fibers became more numerous, thicker, and more twisted; IR alone producd many fine, feathery fibers. The addition of IR to UV resulted in dense matlike elastic fiber depositions that exceeded what was observed with either irradiation alone. In combination or alone UV and IR radiation produced a large increase in ground substance, a finding also seen in actinically damaged human skin. Infrared radiation, in the physiologic range, though pleasant is not innocuous. (orig./MG) [de

  3. Radiation damage measurements on CZT drift strip detectors

    DEFF Research Database (Denmark)

    Kuvvetli, Irfan; Budtz-Jørgensen, Carl; Korsbech, Uffe C C

    2003-01-01

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

  4. Radiation Damage in Si Diodes from Short, Intense Ion Pulses

    Science.gov (United States)

    de Leon, S. J.; Ludewigt, B. A.; Persaud, A.; Seidl, P. A.; Schenkel, T.

    2017-10-01

    The Neutralized Drift Compression Experiment (NDCX-II) at Berkeley Lab is an induction accelerator studying the effects that concentrated ion beams have on various materials. Charged particle radiation damage was the focus of this research - we have characterized a series of Si diodes using an electrometer and calibrated the diodes response using an 241Am alpha source, both before and after exposing the diodes to 1 MeV He ions in the accelerator. The key part here is that the high intensity pulses from NDCX-II (>1010 ions/cm2 per pulse in accelerators, fusion energy experiments and space applications and results from short pulses can inform models of radiation damage evolution. This work was supported by the Office of Science of the US Department of Energy under contract DE-AC0205CH11231.

  5. Radiation damage of steel 15Kh2NMFA and its influencing with copper and phosphorus

    International Nuclear Information System (INIS)

    Vacek, M.; Stoces, B.; Novosad, P.; Brumovsky, M.; Brynda, J.

    1984-01-01

    Experimental melts of CrNiMoV steel (15Kh2NMFA) were used for a study of the effects of copper (0.08 to 0.52%) and phosphorus (0.006 to 0.018%) on radiation damage. Following the roughly same irradiation with a fluence of 2.3x10 23 n/m 2 (E/sub n/>0.5 MeV) the increased radiation damage was in direct proportion to the contents of phosphorus and copper in the steel. The effects of copper are, however, much more explicit than those of phosphorus. In investigated industrial melts with a weight of up to 195 tons the measured radiation embrittlement was within permissible range. The effect was not proved of the weight of melts on their resistance to radiation embrittlement and hardening. (author)

  6. Radiation damage and repair in cells and cell components. Progress report, 1978-1979

    Energy Technology Data Exchange (ETDEWEB)

    Fluke, D.J.; Pollard, E.C.

    1979-01-01

    Special work during the year concentrated on induced repair of cellular radiation damage in a number of strains of Escherchia coli. Ultraviolet and x-radiation are considered for induction of cell damage. (PCS)

  7. Reduction in thermal conductivity of ceramics due to radiation damage

    International Nuclear Information System (INIS)

    Klemens, P.G.; Hurley, G.F.; Clinard, F.W. Jr.

    1976-01-01

    Ceramics are required for a number of applications in fusion reactors. In several of these applications, the thermal conductivity is an important design parameter as it affects the level of temperature and thermal stress in service. Ceramic insulators are known to suffer substantial reduction in thermal conductivity due to neutron irradiation damage. The present study estimates the reduction in thermal conductivity at high temperature due to radiation induced defects. Point, extended, and extended partly transparent defects are considered

  8. Radiation damage status of the ATLAS silicon strip detectors (SCT)

    CERN Document Server

    Kondo, Takahiko; The ATLAS collaboration

    2017-01-01

    The Silicon microstrip detector system (SCT) of the ATLAS experiment at LHC has been working well for about 7 years since 2010. The innermost layer has already received a few times of 10**13 1-MeV neutron-equivalent fluences/cm2. The evolutions of the radiation damage effects on strip sensors such as leakage current and full depletion voltages will be presented.

  9. The effect of radiation damage on the vertex detector efficiency

    CERN Document Server

    Cooke, O

    1997-01-01

    97-023 This note describes a brief study into the effects of the radiation damage on the vertex detectorperformance. The noise increases as the detector is irradiated. Fixing the fraction of noise clusters to 0.1% by adjusting the thresholds brings about a loss in efficiency with increased irradiation. This loss in efficiency is parameterized, and some effects on the B->pi+pi- channel are shown.

  10. The LHCb Vertex Locator – Performance and Radiation Damage

    CERN Document Server

    Oblakowska-Mucha, A

    2014-01-01

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

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

    DEFF Research Database (Denmark)

    Bennetzen, Martin; Andersen, J.S.; Lasen, D.H.

    2013-01-01

    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...

  12. Post-flood damage data: requirements for disaster forensic investigation

    Directory of Open Access Journals (Sweden)

    Dolan Martin

    2016-01-01

    Full Text Available Disaster forensic investigation analyses the unfolding of a disaster and attempts to identify its multiple causes of damage which can lead to (i improved disaster prevention and management from lessons learnt, and (ii more effective mitigation measures in the aftermath of a disaster. The way in which damage data are collected after a flood event as well as the types of collected data influences their usability within forensic investigations. In order to explore whether or not existing data can be used for disaster forensic analysis, the European Project IDEA (Improving Damage assessments to Enhance cost-benefit Analyses is investigating existing gaps in damage information so as to identify possible paths towards improving data quality. This paper focuses in detail on a forensic analysis of the interlinked damage to economic activities and infrastructure in the Severn floods of 2007 in the UK. Besides investigating the usability of existing data, this research investigated: (i the relative weight of direct and indirect costs to business and infrastructure companies; (ii to what extent damage to infrastructure has impacted on indirect damage to businesses. Finally recommendations for improving the data for use in forensic investigation are offered.

  13. Radiation damage and rate limitations in tracking devices

    International Nuclear Information System (INIS)

    Gilchriese, M.G.D.

    1984-01-01

    In this note the author briefly discusses radiation damage to wire chambers and silicon strip devices and the electronics that may be associated with each of these. Scintillating fibers and CCD's are not discussed although the former appears to be a potentially radiation-resistant detector. In order to calculate radiation levels and rates the author assumed the following: an inelastic cross section of 100 mb at the SSC - six charged particles per unit of rapidity - photons and neutrons do not contribute to the background (photon conversions are negligible with a thin Be beam pipe) - beam gas interactions and beam losses (except during injection when I assume that the detector is ''off'') are negligible. This is discussed in a later section. - 1 Rad = 3.5 x 10 7 minimum ionizing particlescm 2

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

    Science.gov (United States)

    McGuigan, Kevin G.

    2008-03-01

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

  15. Radiation damage in indium tin oxide (ITO) layers

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, D.V. [University Coll. of Wales, Cardiff (United Kingdom). School of Electric, Electronic and System Engineering; Salehi, A. [University Coll. of Wales, Cardiff (United Kingdom). School of Electric, Electronic and System Engineering; Aliyu, Y.H. [University Coll. of Wales, Cardiff (United Kingdom). School of Electric, Electronic and System Engineering; Bunce, R.W. [University Coll. of Wales, Cardiff (United Kingdom). School of Electric, Electronic and System Engineering; Diskett, D. [Applied Physics and Electro-optics Group, Cranfield University RMCS, Shrivenham, Swindon SN6 8LA (United Kingdom)

    1995-03-15

    The effects of proton damage on transparent conducting indium tin oxide (ITO) layers were investigated by electrical and optical techniques. ITO layers were found to be highly resistant to proton damage for fluences up to 10{sup 16} ions cm{sup -2}. For fluences greater than 10{sup 16} cm{sup -2} the resistivity rises rapidly with a corresponding degradation of the transmittance. ((orig.))

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

    Science.gov (United States)

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

    2016-11-01

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

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

  18. Defense mechanisms against radiation induced teratogenic damage in mice

    International Nuclear Information System (INIS)

    Kato, F.; Ootsuyama, A.; Nomoto, S.; Norimura, T.

    2002-01-01

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

  19. Pathological investigation of radiation necrosis

    International Nuclear Information System (INIS)

    Nakamura, Nishio; Yoshimura, Noriaki; Ikuta, Fusahiro

    1975-01-01

    The brain and spinal cord of an 18-year-old male, who suffered from cerebellar medulloblastoma with subarachnoid spread, had been irradiated by a large amount of Linac X-ray: 14,450 rads to the lower thoracic segments and 7,400 rads to the lumbar segments. The tumor at the roof of the 4th ventricle had disseminated along the ventricular system but was limited to the subarachnoid space of the cervical spinal cord. No remarkable changes were found in the volume or consistency of the thoracic and lumbar cord. Elasticity of the lower thoracic segment was greatly diminished and the cut surfaces were yellowish white and fragile. Microscopically extensive coagulation necrosis was observed with complete disintegration of myelin and axon. Vascular changes were most prominent in the smaller vessels, eg. hyalinous thickening, concentric cleavage, adventitial fibrosis and edema of small artery perivascular spaces, fibrin thrombi occulusion of arterioles and capillaries, and telangiectasia. In the lumbar spinal cord, moderate neuronal degeneration and protoplasmic astrocytosis were observed. Changes in the lumbar posterior white column were considered to be not only secondary degeneration but also a primary lesion caused by irradiation. Liquefactive necrosis in the gray matter of the cervical cord was thought to be a nonspecific circulatory disturbance because of the absence of vascular changes. Vascular changes were thought to be very important in the histological diagnosis of radiation myelopathy and it was supposed that increased permeability of the vessel walls was a factor in coagulation necrosis. They considered this case to have typical histology of radiation myelopathy. (Evans, J.)

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

    International Nuclear Information System (INIS)

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

    1980-01-01

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

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

    CERN Document Server

    Ducourthial, Audrey; The ATLAS collaboration

    2017-01-01

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

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

    CERN Document Server

    Ducourthial, Audrey; The ATLAS collaboration

    2017-01-01

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

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

    CERN Document Server

    Rossini, Lorenzo; The ATLAS collaboration

    2018-01-01

    Silicon pixel detectors are at the core of the current and planned upgrade of the ATLAS detector at the Large Hadron Collider (LHC). As the closest detector component to the interaction point, these detectors will be subjected to a significant amount of radiation over their lifetime: prior to the High-Luminosity LHC (HL-LHC), the innermost layers will receive a fluence in excess of 10^15 neq/cm^2 and the HL-HLC detector upgrades must cope with an order of magnitude higher fluence integrated over their lifetimes. Simulating radiation damage is critical in order to make accurate predictions for current and future detector performance that will enable searches for new particles and forces as well as precision measurements of Standard Model particles such as the Higgs boson. We present a digitization model that includes radiation damage effects to the ATLAS pixel sensors for the first time and considers both planar and 3D sensor designs. In addition to thoroughly describing the setup, we compare predictions for b...

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

    Science.gov (United States)

    Ducourthial, A.

    2018-03-01

    Silicon pixel detectors are at the core of the current and planned upgrade of the ATLAS detector at the Large Hadron Collider (LHC) . As the closest detector component to the interaction point, these detectors will be subject to a significant amount of radiation over their lifetime: prior to the High-Luminosity LHC (HL-LHC) [1], the innermost layers will receive a fluence in excess of 1015 neq/cm2 and the HL-LHC detector upgrades must cope with an order of magnitude higher fluence integrated over their lifetimes. Simulating radiation damage is essential in order to make accurate predictions for current and future detector performance that will enable searches for new particles and forces as well as precision measurements of Standard Model particles such as the Higgs boson. We present a digitization model that includes radiation damage effects on the ATLAS pixel sensors for the first time. In addition to thoroughly describing the setup, we present first predictions for basic pixel cluster properties alongside early studies with LHC Run 2 proton-proton collision data.

  5. Analysis of radiation damage in fusion-simulation neutron spectra

    International Nuclear Information System (INIS)

    Parkin, D.M.; Goland, A.N.

    1975-01-01

    Various parameters which are relevant to an understanding of radiation effects in metals have been evaluated utilizing available neutron spectrum information for several existing sources, e.g., EBRII, HFIR, and LAMPF, as well as the hypothetical spectrum at a fusion reactor first wall, and measured Li(d,n) spectra. Recoil energy distributions were calculated for several metals including Al, Cu, and Nb. The recoil energy range was divided into groups, and the fraction of recoils occurring in each energy group was compared with the fraction of the damage energy contributed by that group. From this comparison it was possible to conclude that the significant recoil range differs by about an order of magnitude between fission and fusion sources. The analysis further confirms that basic defect production characteristics depend upon the neutron spectrum, and that integral calculations of radiation-effect parameters do not provide a complete description of the dependence. This is equally true for comparisons between fusion-related spectra or fission-reactor spectra independently. Four recoil-dependent parameter functions which describe different aspects of radiation damage were used in the calculations. The relative effectiveness of neutron sources was found to depend upon the choice of parameter function. Fission-reactor spectra comparisons are relatively insensitive to the parameter functions used whereas spectra with an appreciable component of high-energy neutrons are much more sensitive

  6. Radiation Damage in Si Diodes from Short, Intense Ion Pulses

    Science.gov (United States)

    de Leon, S. J.; Ludewigt, B. A.; Persaud, A.; Seidl, P. A.; Schenkel, T.

    2017-10-01

    The Neutralized Drift Compression Experiment (NDCX-II) at Berkeley Lab is an induction accelerator studying the effects that concentrated ion beams have on various materials. Charged particle radiation damage was the focus of this research - we have characterized a series of Si diodes using an electrometer and calibrated the diodes response using an 241Am alpha source, both before and after exposing the diodes to 1 MeV He ions in the accelerator. The key part here is that the high intensity pulses from NDCX-II (>1010 ions/cm2 per pulse in charge collection efficiency and an increase in leakage current. Testing dose-rate effects in Si diodes and other semiconductors is a crucial step in designing sustainable instruments that can encounter high doses of radiation, such as high intensity accelerators, fusion energy experiments and space applications and results from short pulses can inform models of radiation damage evolution. This work was supported by the Office of Science of the US Department of Energy under contract DE-AC0205CH11231.

  7. DNA damage in Fabry patients: An investigation of oxidative damage and repair.

    Science.gov (United States)

    Biancini, Giovana Brondani; Moura, Dinara Jaqueline; Manini, Paula Regina; Faverzani, Jéssica Lamberty; Netto, Cristina Brinckmann Oliveira; Deon, Marion; Giugliani, Roberto; Saffi, Jenifer; Vargas, Carmen Regla

    2015-06-01

    Fabry disease (FD) is a lysosomal storage disorder associated with loss of activity of the enzyme α-galactosidase A. In addition to accumulation of α-galactosidase A substrates, other mechanisms may be involved in FD pathophysiology, such as inflammation and oxidative stress. Higher levels of oxidative damage to proteins and lipids in Fabry patients were previously reported. However, DNA damage by oxidative species in FD has not yet been studied. We investigated basal DNA damage, oxidative DNA damage, DNA repair capacity, and reactive species generation in Fabry patients and controls. To measure oxidative damage to purines and pyrimidines, the alkaline version of the comet assay was used with two endonucleases, formamidopyrimidine DNA-glycosylase (FPG) and endonuclease III (EndoIII). To evaluate DNA repair, a challenge assay with hydrogen peroxide was performed. Patients presented significantly higher levels of basal DNA damage and oxidative damage to purines. Oxidative DNA damage was induced in both DNA bases by H2O2 in patients. Fabry patients presented efficient DNA repair in both assays (with and without endonucleases) as well as significantly higher levels of oxidative species (measured by dichlorofluorescein content). Even if DNA repair be induced in Fabry patients (as a consequence of continuous exposure to oxidative species), the repair is not sufficient to reduce DNA damage to control levels. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Stem cell therapy for the treatment of radiation-induced normal tissue damage

    International Nuclear Information System (INIS)

    Chapel, A.; Benderitter, M.; Gourmelon, P.; Lataillade, J.J.; Gorin, N.C.

    2013-01-01

    Radiotherapy may induce irreversible damage on healthy tissues surrounding the tumour. In Europe, per year, 1.5 million patients undergo external radiotherapy. Acute adverse effect concern 80% of patients. The late adverse effect of radiotherapy concern 5 to 10% of them, which could be life threatening. Eradication of these manifestations is crucial. The French Institute of Radioprotection and Nuclear Safety (IRSN) contribute to understand effect of radiation on healthy tissue. IRSN is strongly implicated in the field of regeneration of healthy tissue after radiotherapy or radiological accident and in the clinical use of cell therapy in the treatment of irradiated patients. Our first success in cell therapy was the correction of deficient hematopoiesis in two patients. The intravenous injection of Mesenchymal Stem Cells (MSC) has restored bone marrow micro-environment after total body irradiation necessary to sustain hematopoiesis. Cutaneous radiation reactions play an important role in radiation accidents, but also as a limitation in radiotherapy and radio-oncology. We have evidenced for the first time, the efficiency of MSC therapy in the context of acute cutaneous and muscle damage following irradiation in five patients. Concerning the medical management of gastrointestinal disorder after irradiation, we have demonstrated the promising approach of the MSC treatment. We have shown that MSC migrate to damaged tissues and restore gut functions after radiation damage. The evaluation of stem cell therapy combining different sources of adult stem cells is under investigation

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

    NARCIS (Netherlands)

    Loch, R.A.; Sobierajski, R.; Louis, Eric; Bosgra, J.; Bosgra, J.; Bijkerk, Frederik

    2012-01-01

    The single shot damage thresholds of multilayer optics for highintensity short-wavelength radiation sources are theoretically investigated, using a model developed on the basis of experimental data obtained at the FLASH and LCLS free electron lasers. We compare the radiation hardness of commonly

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-04-15

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

  11. Multiscale physics of ion-induced radiation damage.

    Science.gov (United States)

    Surdutovich, Eugene; Solov'yov, A V

    2014-01-01

    This is a review of a multiscale approach to the physics of ion-beam cancer therapy, an approach suggested in order to understand the interplay of a large number of phenomena involved in the radiation damage scenario occurring on a range of temporal, spatial, and energy scales. We describe different effects that take place on different scales and play major roles in the scenario of interaction of ions with tissue. The understanding of these effects allows an assessment of relative biological effectiveness that relates the physical quantities, such as dose, to the biological values, such as the probability of cell survival. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Covariances for the 56Fe radiation damage cross sections

    Directory of Open Access Journals (Sweden)

    Simakov Stanislav P.

    2017-01-01

    Full Text Available The energy-energy and reaction-reaction covariance matrices were calculated for the n + 56Fe damage cross-sections by Total Monte Carlo method using the TENDL-2013 random files. They were represented in the ENDF-6 format and added to the unperturbed evaluation file. The uncertainties for the spectrum averaged radiation quantities in the representative fission, fusion and spallation facilities were first time assessed as 5–25%. Additional 5 to 20% have to be added to the atom displacement rate uncertainties to account for accuracy of the primary defects simulation in materials. The reaction-reaction correlation were shown to be 1% or less.

  13. Compilation of radiation damage test data cable insulating materials

    CERN Document Server

    Schönbacher, H; CERN. Geneva

    1979-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-10-01

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

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

    CERN Document Server

    Nachman, Benjamin Philip; The ATLAS collaboration

    2017-01-01

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

  16. Particle radiation-induced genetic damage in vivo

    International Nuclear Information System (INIS)

    Chang, P.Y.; Bakke, J.; Lin, S.

    2003-01-01

    Full text: Assessment of radiation-induced alterations in the genomic is important to determine both short and long-term effects after exposure. Transgenic mouse mutation model systems, based on the insertion of specific target genes into the genome of every cell of the animals, provide a rapid and efficient means to obtain statistically reliable results on the frequencies of mutations in all tissues without requiring prior drug selection and clonal expansion of the target cells. We are using the plasmid-based lacZ transgenic mouse model system to measure the dose- and temporal-dependent particle-radiation induced responses. We measured cytogenetic damage to the hematopoietic system as well as mutations in the transgene in both the brain and spleen tissues after an acute dose of 250 MeV/amu protons or 1 GeV/amu iron ions. The level of peripheral blood micronucleated reticulocytes (MN-RET) increased dramatically within 48 h after whole body exposure for both proton or iron irradiated animals and returned to control levels within 1 week after treatment suggesting that these severely damaged transient cell populations are rapidly eliminated from the body. Mutation frequencies (MF) of the lacZ transgene increased as a function of proton dose in the spleen and brain tissues at 1, 8 and 16 wks post irradiation. We demonstrated that the MF of the lacZ target transgene was responsive to low doses of protons with significant increases in the MF (p 0.5 Gy iron ions. The overall magnitude of induction of lacZ MF in the brain is lower than that of the spleen, suggesting that radiation-induced genetic effects are tissue-specific, and tissue physiology plays a role in determining the late effects after particle radiation. This work was supported by NASA/NSBRI NCC 9-58-163

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

    Science.gov (United States)

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

    2014-01-01

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

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

    International Nuclear Information System (INIS)

    Herst, Patries M

    2014-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-06-15

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

  20. Synchrotron radiation. 4. Analyses of biological samples using synchrotron radiation. 3. Research on radiation damage to DNA using synchrotron radiation

    International Nuclear Information System (INIS)

    Takakura, Kaoru

    1998-01-01

    This review described how the synchrotron radiation (SR) is used to solve problems unknown hitherto in radiation biology. Historically, the target substance of UV light in bacterial death was suggested to be nucleic acid in 1930. Researches on the radiation damage to DNA were begun at around 1960 and have mainly used UV light, X-ray and γray. Soft X-ray and vacuum UV whose energy covering from several eV to scores of keV have not been used since UV and X-ray lack the energy of this range. This is one of reasons why detailed process leading to radiation-induced death, carcinogenicity and mutation has not been known hitherto. RS possesses wide range of energy, i.e., from UV to hard X-ray, of high intensity, which is helpful for studying the unknown problems. The RS studies were begun in nineteen-seventies. Those include the action spectrum studies and atomic target studies. In the former, the course of the effect, e.g., the mechanism of DNA double strand breakage, can be elucidated. In the latter, photon of known energy can be irradiated to the specified atom like phosphorus in DNA which elucidating the precise physicochemical process of the breakage. Use of RS in these studies is thought still meaningful in future. (K.H.) 62 refs

  1. Relation between four types of radiation damage and induced repair

    International Nuclear Information System (INIS)

    Radar, M.L.

    1977-08-01

    Four strains of Escherichia coli were exposed to uv and gamma radiation. Procedures are described for mutational studies, classification of revertants, inhibition of postirradiation DNA degradation and radioresistance. Comparisons were made of induction of the error-prone repair (epr) system with four mutagens; uv radiation, near uv radiation, gamma radiation, and DNA-protein crosslinks. An increase in the number of mutations was shown in every case. The observation that induction of mutagenesis, induction of inhibition of post-irradiation DNA degradation, and induction of radioresistance are closely parallel phenomena led to the investigation of the possibility that DNA-protein crosslinks which were known mutagens were also inducers of the epr system. The significance of the results is discussed

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

    International Nuclear Information System (INIS)

    Toyota, Hiroyuki; Shimada, Takanobu; Takahashi, You; Imamura, Takeshi; Hada, Yuko; Ishii, Takako T.; Isobe, Hiroaki; Asai, Ayumi; Shiota, Daikou

    2013-01-01

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

  3. The Juno Radiation Monitoring (RM) Investigation

    DEFF Research Database (Denmark)

    Becker, H. N.; Alexander, J. W.; Adriani, A.

    2017-01-01

    The Radiation Monitoring Investigation of the Juno Mission will actively retrieve and analyze the noise signatures from penetrating radiation in the images of Juno’s star cameras and science instruments at Jupiter. The investigation’s objective is to profile Jupiter’s > 10-MeV electron environment...... of the instruments, calibrations performed prior to Juno’s first science orbit, and how the measurements may be used to infer the external relativistic electron environment....

  4. Nuclear radiation applications in hydrological investigations

    International Nuclear Information System (INIS)

    Rao, S.M.

    1978-01-01

    The applications of radiation sources for the determination of water and soil properties in hydrological investigations are many and varied. These include snow gauging, soil moisture and density determinations, measurement of suspended sediment concentrations in natural streams and nuclear well logging for groundwater exploitation. Besides the above, many radiation physics aspects play an important role in the development of radiotracer techniques, particularly in sediment transport studies. The article reviews the above applications with reference to their limitations and advantages. (author)

  5. The radiation damage in silicon diodes induced by stray fast neutrons from the ANSTO Cyclotron

    International Nuclear Information System (INIS)

    Mukherjee, B.

    1996-01-01

    Intense flux of fast neutrons are produced during routine isotope production runs at the National Medical Cyclotron. These stray neutrons induce irreversible displacement damage in the semiconductor devices, the vital building blocks of the various electronic instruments used in the facility. This poster highlights the results of the radiation hardness investigation study of commercial silicon diodes undertaken at the Health Physics laboratory of the National Medical Cyclotron

  6. Study of the effect of dose-rate on radiation-induced damage to human erythrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Krokosz, Anita [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, Lodz (Poland)]. E-mail: krokosz@biol.uni.lodz.pl; Koziczak, Renata [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, Lodz (Poland); Gonciarz, Marta [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, Lodz (Poland); Szweda-Lewandowska, Zofia [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, Lodz (Poland)

    2006-01-15

    Human erythrocytes suspended in an isotonic Na-phosphate buffer, pH 7.4 (hematocrit of 2%) were irradiated with {gamma}-rays at three dose-rates of 66.7, 36.7, 25 Gy min{sup -1} in order to investigate the influence of the dose-rate on radiation-induced membrane damage, hemoglobin oxidation and loss of reduced glutathione. The obtained results showed that such processes as erythrocyte hemolysis, lipid and protein destruction depend on the radiation dose-rate. The parameter values describing these processes showed an inverse dose-rate effect.

  7. Study of the effect of dose-rate on radiation-induced damage to human erythrocytes

    International Nuclear Information System (INIS)

    Krokosz, Anita; Koziczak, Renata; Gonciarz, Marta; Szweda-Lewandowska, Zofia

    2006-01-01

    Human erythrocytes suspended in an isotonic Na-phosphate buffer, pH 7.4 (hematocrit of 2%) were irradiated with γ-rays at three dose-rates of 66.7, 36.7, 25 Gy min -1 in order to investigate the influence of the dose-rate on radiation-induced membrane damage, hemoglobin oxidation and loss of reduced glutathione. The obtained results showed that such processes as erythrocyte hemolysis, lipid and protein destruction depend on the radiation dose-rate. The parameter values describing these processes showed an inverse dose-rate effect

  8. Nuclear microprobe investigation of the effects of ionization and displacement damage in vertical, high voltage GaN diodes

    Science.gov (United States)

    Vizkelethy, G.; King, M. P.; Aktas, O.; Kizilyalli, I. C.; Kaplar, R. J.

    2017-08-01

    Radiation responses of high-voltage, vertical gallium-nitride (GaN) diodes were investigated using Sandia National Laboratories' nuclear microprobe. Effects of the ionization and the displacement damage were studied using various ion beams. We found that the devices show avalanche effect for heavy ions operated under bias well below the breakdown voltage. The displacement damage experiments showed a surprising effect for moderate damage: the charge collection efficiency demonstrated an increase instead of a decrease for higher bias voltages.

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

    International Nuclear Information System (INIS)

    Naguib, N.I.

    2011-01-01

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

  10. The LHCb VELO: Performance, Radiation Damage, and Upgrade

    International Nuclear Information System (INIS)

    Hennessy, Karol

    2013-06-01

    LHCb is a dedicated experiment to study New Physics and CP violation in the decays of heavy hadrons at the Large Hadron Collider (LHC). Heavy hadrons are identified through their flight distance in the VELO, the retractable silicon strip vertex detector surrounding the LHCb interaction point at only 7 mm from the beam during normal LHC operation. Two VELO halves comprise 21 silicon micro-strip modules each. The performance of the VELO in its three years of successful operation during the LHC physics runs is presented. Highlights include cluster finding efficiency, single hit resolution, and impact parameter and vertex resolutions. The VELO sensors receive a large and non-uniform radiation dose having inner and outer radii of only 7 and 50 mm, respectively. In this extreme and highly non-uniform radiation environment type-inversion of the inner part of the n + -on-n sensors has already been measured. Radiation damage is monitored and studied in three ways: (1) dependence of sensor currents with fluence, (2) evolution of the depletion voltage, and (3) cluster finding efficiency. Results will be presented in all three areas with updates based on recent results. Current research on upgrades to the VELO are outlined to adapt to a new 40 MHz trigger. Main focus given to the silicon technology to be used in the upgrade. Other aspects such as the cooling and readout requirements are also given. (authors)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-12-15

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

  12. Action of the chlorophyllin on the genetic damage induced by gamma radiation in germinal cells of Drosophila Melanogaster

    International Nuclear Information System (INIS)

    Cruces, M.P.; Pimentel, A.E.; Moreno, A.; Moreno, R.

    2003-01-01

    The obtained results using somatic cells, they have evidenced that the chlorophyllin (CHLN) it can act inhibiting or increasing the damage caused by different mutagens. The objective of this investigation is to evaluate the effect of the CHLN on the damage induced by gamma radiation in germinal cells of Drosophila. Two tests were used, the lost of the X chromosome and the conventional test of lethal recessive bound to the sex (LRLS); both with a system of litters. The obtained results in both essays, indicated that the CHLN doesn't reduce the damage induced by the gamma radiation in none of the cellular monitored states. (Author)

  13. 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.

  14. Radiation damages in chemical components of organic scintillator detectors

    International Nuclear Information System (INIS)

    Fernandes Neto, Jose Maria

    2003-01-01

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

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

    International Nuclear Information System (INIS)

    Nave, Colin; Sutton, Geoff; Evans, Gwyndaf; Owen, Robin; Rau, Christoph; Robinson, Ian; Stuart, David Ian

    2016-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-01-01

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

  17. High and Low LET Radiation Differentially Induce Normal Tissue Damage Signals

    Energy Technology Data Exchange (ETDEWEB)

    Niemantsverdriet, Maarten [Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Department of Cell Biology, Section of Radiation and Stress Cell Biology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Goethem, Marc-Jan van [Department of Cell Biology, Section of Radiation and Stress Cell Biology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Kernfysisch Versneller Instituut, University of Groningen, Groningen (Netherlands); Bron, Reinier; Hogewerf, Wytse [Department of Cell Biology, Section of Radiation and Stress Cell Biology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Brandenburg, Sytze [Kernfysisch Versneller Instituut, University of Groningen, Groningen (Netherlands); Langendijk, Johannes A.; Luijk, Peter van [Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Coppes, Robert P., E-mail: r.p.coppes@umcg.nl [Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Department of Cell Biology, Section of Radiation and Stress Cell Biology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands)

    2012-07-15

    Purpose: Radiotherapy using high linear energy transfer (LET) radiation is aimed at efficiently killing tumor cells while minimizing dose (biological effective) to normal tissues to prevent toxicity. It is well established that high LET radiation results in lower cell survival per absorbed dose than low LET radiation. However, whether various mechanisms involved in the development of normal tissue damage may be regulated differentially is not known. Therefore the aim of this study was to investigate whether two actions related to normal tissue toxicity, p53-induced apoptosis and expression of the profibrotic gene PAI-1 (plasminogen activator inhibitor 1), are differentially induced by high and low LET radiation. Methods and Materials: Cells were irradiated with high LET carbon ions or low LET photons. Cell survival assays were performed, profibrotic PAI-1 expression was monitored by quantitative polymerase chain reaction, and apoptosis was assayed by annexin V staining. Activation of p53 by phosphorylation at serine 315 and serine 37 was monitored by Western blotting. Transfections of plasmids expressing p53 mutated at serines 315 and 37 were used to test the requirement of these residues for apoptosis and expression of PAI-1. Results: As expected, cell survival was lower and induction of apoptosis was higher in high -LET irradiated cells. Interestingly, induction of the profibrotic PAI-1 gene was similar with high and low LET radiation. In agreement with this finding, phosphorylation of p53 at serine 315 involved in PAI-1 expression was similar with high and low LET radiation, whereas phosphorylation of p53 at serine 37, involved in apoptosis induction, was much higher after high LET irradiation. Conclusions: Our results indicate that diverse mechanisms involved in the development of normal tissue damage may be differentially affected by high and low LET radiation. This may have consequences for the development and manifestation of normal tissue damage.

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

    Science.gov (United States)

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

    2011-01-01

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

  19. Radiation damage studies on natural rock salt from various geological localities of interest to the radioactive waste disposal program

    International Nuclear Information System (INIS)

    Levy, P.W.

    1981-01-01

    As part of a program to investigate radiation damage in geological materials of interest to the radioactive waste disposal program, radiation damage, particularly radiation induced sodium metal colloid formation, has been studied in 14 natural rock salt samples. All measurements were made with equipment for making optical absorption and other measurements on samples, in a temperature controlled irradiation chamber, during and after 0.5 to 3.0 MeV electron irradiation. Samples were chosen for practical and scientific purposes, from localities that are potential repository sites and from different horizons at certain localities

  20. Magnetic resonance imaging (MRI): A review of genetic damage investigations.

    Science.gov (United States)

    Vijayalaxmi; Fatahi, Mahsa; Speck, Oliver

    2015-01-01

    Magnetic resonance imaging (MRI) is a powerful, non-invasive diagnostic medical imaging technique widely used to acquire detailed information about anatomy and function of different organs in the body, in both health and disease. It utilizes electromagnetic fields of three different frequency bands: static magnetic field (SMF), time-varying gradient magnetic fields (GMF) in the kHz range and pulsed radiofrequency fields (RF) in the MHz range. There have been some investigations examining the extent of genetic damage following exposure of bacterial and human cells to all three frequency bands of electromagnetic fields, as used during MRI: the rationale for these studies is the well documented evidence of positive correlation between significantly increased genetic damage and carcinogenesis. Overall, the published data were not sufficiently informative and useful because of the small sample size, inappropriate comparison of experimental groups, etc. Besides, when an increased damage was observed in MRI-exposed cells, the fate of such lesions was not further explored from multiple 'down-stream' events. This review provides: (i) information on the basic principles used in MRI technology, (ii) detailed experimental protocols, results and critical comments on the genetic damage investigations thus far conducted using MRI equipment and, (iii) a discussion on several gaps in knowledge in the current scientific literature on MRI. Comprehensive, international, multi-centered collaborative studies, using a common and widely used MRI exposure protocol (cardiac or brain scan) incorporating several genetic/epigenetic damage end-points as well as epidemiological investigations, in large number of individuals/patients are warranted to reduce and perhaps, eliminate uncertainties raised in genetic damage investigations in cells exposed in vitro and in vivo to MRI. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Protection of DPPC phospholipid liposomal membrane against radiation oxidative damage by antioxidants

    Energy Technology Data Exchange (ETDEWEB)

    Marathe, D.L.; Pandey, B.N.; Mishra, K.P [Bhabha Atomic Research Centre, Mumbai (India)

    2000-05-01

    Investigations in our laboratory on egg lecithin liposomes have recently showed a marked protection against damage by gamma radiation when cholesterol was present in the composition of vesicles suggesting a role of bilayer molecular architecture in the mechanism of free radical mediated lipid peroxidation. Present study was designed to determine the changes in bilayer permeability in DPPC unilamelar vesicles after exposure to gamma radiation by monitoring the leakage of pre-loaded carboxyfluorescein (CF), a marker loaded in aqueous interior of vesicle and fluidity alterations in the bilayer using fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH), a membrane bilayer probe. It was found that radiation doses of an order of magnitude higher were required to produce detectable changes in vesicles of DPPC than in the vesicles of egg lecithin suggesting a modulating role of chemical nature of composition in the membrane radiation sensitivity. It was significant to find that the leakage of CF from and incorporation of DPH into vesicle bilayer showed similar response pattern to radiation doses (0.1-6 kGy) which was also found to be dose rate dependent. Presence of antioxidants; alpha-tocopherol (0.15 mole %) in the bilayer membrane or ascorbic acid (0.1 mM) in the aqueous region significantly protected DPPC vesicles from radiation damage as determined from DPH uptake kinetics suggesting involvement of reactive free radicals of lipids as well as water radicals in the mechanism of membrane peroxidative damage. The magnitude of protection was found to increase with the increasing concentration of both these antioxidants but comparisons showed that {alpha}-tocopherol was far more effective in protecting the vesicles than ascorbic acid. These results contribute to our understanding of the mechanism of radiation oxidative damage and its modification by radical scavenging and/or organizational modulation which emphasize the importance of structure and composition of

  2. Radiation damage in amorphous solids - a computer simulation

    International Nuclear Information System (INIS)

    Chaki, T.K.; Li, J.C.M.

    1984-01-01

    It is known for crystalline materials that injection of high energy atoms introduces point defects. The nature of defects is not known for amorphous solids. So a molecular dynamic simulation of radiation damage in an amorphous metal was carried out. An amorphous structure of 685 atoms with periodic boundary conditions in all 3 dimensions was equilibrated first. Then one atom on the surface was given a high initial velocity so it was injected inward. Radial temperature distribution around the line of injection was calculated as a function of time. Void distribution and its evolution with time in the direction of injection was calculated by counting the atomic centers in thin slabs perpendicular to the line of injection. The swelling of the whole solid was calculated also. Some results are compared with experiments

  3. Collision density approach of radiation damage in a multispecies medium

    International Nuclear Information System (INIS)

    Lux, I.; Pazsit, I.

    1981-01-01

    Space-energy dependent forward type equations for the collision densities of energetic atoms in a multispecies semi-infinite homogeneous medium are formulated. Introduction of the one-dimensional isotropic forward-backward model of Fermi for the scattering and application of the Laplace transform with respect to the lethargy variable will lead to a linear differential equation system with constant coefficients. This equation system is solved for an arbitrary number of species and relations between the collision densities and defect distributions of the different species are given in the Kinchin-Pease model of radiation damage. The case of an alien particle incident on a two-component target is examined in some detail and the sputtering spectra for the three species are given numerically. (author)

  4. Biological rhythms for rehabilitation of radiation damage of population

    International Nuclear Information System (INIS)

    Goncharova, T.G.; Vasil'eva, G.S.; Efimov, M.L.

    1999-01-01

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

  5. Sensitization of ultraviolet radiation damage in bacteria and mammalian cells

    International Nuclear Information System (INIS)

    Fisher, G.J.; Watts, M.E.; Patel, K.B.; Adams, G.E.

    1978-01-01

    Bacteria (Serratia marcescens) and mammalian cells (Chinese hamsters V79-379A) were irradiated in monolayers with ultraviolet light at 254 nm or 365 nm in the presence or absence of radiosensitizing drugs. At 254 nm, killing is very efficient (Dsub(37) approximately equal 1 J m -2 exposure, or approximately equal 6 x 10 4 photons absorbed by DNA per bacterium), and sensitizers have no effect. At 365 nm, cells are not killed in buffer, but are inactivated in the presence of nifurpipone or misonidazole. Lethal exposures (approximately equal 5 x 10 3 J m -2 at 10 nM misonidazole) correspond to about 10 7 photons absorbed by sensitizer molecules per bacterium. Toxicity of stable photoproducts of the drugs is not involved, nor is oxygen required. Hence the transient species formed by photo-excitation of radiosensitizer molecules are capable of killing cells in the absence of other types of radiation damage. (author)

  6. Perinatal radiation-induced renal damage in the beagle

    International Nuclear Information System (INIS)

    Jaenke, R.S.; Angleton, G.M.

    1990-01-01

    The developing perinatal kidney is particularly sensitive to radiation. The pathogenesis of the radiation-induced lesion is related to the destruction of outer cortical developing nephrons and direct radiation injury with secondary hemodynamic alterations in remnant nephrons. In this study, which is part of a life span investigation of the effects of whole-body gamma radiation during prenatal and early postnatal life, dogs were given 0, 0.16, 0.83, or 1.25 Gy irradiation at either 55 days postcoitus or 2 days postpartum and were examined morphometrically and histopathologically at 70 days of age. Although irradiated dogs showed no reduction in the total number of nephrons per kidney, there was a significant increase in the total number and relative percentage of immature, dysplastic glomeruli. In addition, deeper cortical glomeruli of irradiated kidneys exhibited mesangial sclerosis similar to that associated with progressive renal failure in our previous studies. These findings are in accord with those reported at doses of 2.24 to 3.57 Gy and demonstrate that the perinatal kidney is affected by radiation doses much lower than previously demonstrated

  7. Silicon P.I.N. Junctions used for studies of radiation damage

    International Nuclear Information System (INIS)

    Lanore, J.

    1964-06-01

    Irradiation of silicon P.I.N. junction has been studied primarily for the purpose of developing a radiation damage dosimeter, but also for the purpose of investigating silicon itself. It is known that the rate of recombination of electrons and holes is a linear function of defects introduced by neutron irradiation. Two methods have been used to measure that rate of recombination: forward characteristic measurements, recovery time measurements. In order to explain how these two parameters depend on recombination rate we have given a theory of the P.I.N. junction. We have also given an idea of the carrier lifetime dependence versus temperature. Annealing effects in the range of 70 to 700 K have also been studied, we found five annealing stages with corresponding activation energies. As an application for these studies, we developed a radiation damage dosimeter with which we made several experiments in facilities such as Naiade or Marias. (author) [fr

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

    International Nuclear Information System (INIS)

    Di Giorgio, M.; Nasazzi, N.B.; Taja, M.R.

    1998-01-01

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

  9. Dislocations and radiation damage in α-uranium

    International Nuclear Information System (INIS)

    Leteurtre, J.

    1969-01-01

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

  10. Bystander effects: intercellular transmission of radiation damage signals

    Energy Technology Data Exchange (ETDEWEB)

    Little, J.B.; Azzam, E.I.; Toledo, S.M. de; Nagasawa, H

    2002-07-01

    Biological effects were examined in confluent cultures of fibroblasts and epithelial cells exposed to very low mean doses of alpha radiation, doses by which only 1-2% of the cells were actually traversed by an alpha particle. Enhanced frequencies of sister chromatid exchanges and HPRT mutations occurred in the non-irradiation, 'bystander' cells associated with a similar increase in the frequency of micronuclei, indicating the induction of DNA damage in these cells. In order to gain information concerning molecular pathways, changes in gene expression were examined in bystander cells by western analysis and in situ immunofluorescence staining. The expression levels of p53, p21 and MDM2 were significantly modulated in bystander cells: the damage signals leading to these changes were transmitted from irradiated to bystander cells by gap junction mediated intracellular communication. The bystander response was suppressed by incubation with superoxide dismutase as well as an inhibitor of NADPH oxidase, suggesting the effect may be mediated by oxidative stress. To examine other signalling pathways responsive to oxidative stress, the activation of stress-related kinases and their downstream transcription factors were analysed in bystander cells by western blotting and electrophoretic mobility shift assays: a 2-4 fold increase in the phosphorylation levels of JNK, EPK1/2, p90RSK, Elk-1 and ATF2 was observed. These changes were detected by 15 min after irradiation and persisted for at least 1 h. These findings indicate the activation of multiple signal transduction pathways in bystander cells, involving signals arising from the plasma membrane as well as from DNA damage. (author)

  11. Effect of substrate temperature on the radiation damage from MeV Si implantation in Si

    International Nuclear Information System (INIS)

    Yu, X.K.; Shao Lin; Rusakova, Irene; Wang, X.M.; Ma, K.B.; Chen, H.; Liu, Jiarui; Chu, W.-K.

    2006-01-01

    We have investigated the radiation damage by MeV implantation of Si in Si and its evolution under thermal annealing. Si wafers were implanted with MeV Si at various substrate temperatures. Damages were characterized by Rutherford-backscattering (RBS) channeling and by transmission electron microscopy (TEM). Defect formation after post-implantation annealing is very sensitive to the substrate temperatures during implantation. When the substrate temperature was decreased to 200 K, TEM revealed two distinct bands of damage after annealing: one around the mean projected ion range and another at half the projected range. Our study indicates that the formation of defects at half range results from the solid phase epitaxy growth of initial buried amorphous layers

  12. Factors influencing heterogeneity of radiation-induced DNA-damage measured by the alkaline comet assay

    International Nuclear Information System (INIS)

    Seidel, Clemens; Lautenschläger, Christine; Dunst, Jürgen; Müller, Arndt-Christian

    2012-01-01

    To investigate whether different conditions of DNA structure and radiation treatment could modify heterogeneity of response. Additionally to study variance as a potential parameter of heterogeneity for radiosensitivity testing. Two-hundred leukocytes per sample of healthy donors were split into four groups. I: Intact chromatin structure; II: Nucleoids of histone-depleted DNA; III: Nucleoids of histone-depleted DNA with 90 mM DMSO as antioxidant. Response to single (I-III) and twice (IV) irradiation with 4 Gy and repair kinetics were evaluated using %Tail-DNA. Heterogeneity of DNA damage was determined by calculation of variance of DNA-damage (V) and mean variance (Mvar), mutual comparisons were done by one-way analysis of variance (ANOVA). Heterogeneity of initial DNA-damage (I, 0 min repair) increased without histones (II). Absence of histones was balanced by addition of antioxidants (III). Repair reduced heterogeneity of all samples (with and without irradiation). However double irradiation plus repair led to a higher level of heterogeneity distinguishable from single irradiation and repair in intact cells. Increase of mean DNA damage was associated with a similarly elevated variance of DNA damage (r = +0.88). Heterogeneity of DNA-damage can be modified by histone level, antioxidant concentration, repair and radiation dose and was positively correlated with DNA damage. Experimental conditions might be optimized by reducing scatter of comet assay data by repair and antioxidants, potentially allowing better discrimination of small differences. Amount of heterogeneity measured by variance might be an additional useful parameter to characterize radiosensitivity

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-03-01

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

  14. Study of the radiation damage of silicon photomultipliers

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-01

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

  15. Nuclear data for analysis of radiation damage processes

    International Nuclear Information System (INIS)

    Aruga, Takeo

    1999-01-01

    Parameters needed to analyze radiation damages for neutron irradiations are presented, taking iron samples irradiated with JMTR neutrons for an example. Special interests have been put on a comparison between results obtained by irradiations for one case with a full neutron spectrum and the other with a Cd-shielded neutron spectrum. A possibility is described that although atomic displacement rates for the two case differ only less than 2%, production rates of freely migrating defects can differ appreciably, due to recoiled atoms by (n, γ) reactions. More over, it is also suggested that although the median energy of PKA, defined as a PKA energy above (or below) which one half of the total atomic displacements are to be produced, may differ only slightly between the two cases, final radiation effects can be significantly different. The effects of charged particles emitted with high energies due to nucleon irradiations are stressed in relation to the significance of defects produced by PKAs with lower energies than several keV, especially for the case of irradiations with highly energetic nucleons as anticipated in GeV proton irradiations. (author)

  16. Radiation damage on p-type silicon detectors

    CERN Document Server

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

    1999-01-01

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

  17. Increase of radiation damage to potassium-ion permeability in E. coli cells with decrease in membrane fluidity

    International Nuclear Information System (INIS)

    Suzuki, S.

    1980-01-01

    Membrane lipids of an auxotroph of E. coli requiring unsaturated fatty acid were manipulated by supplementing the growth medium with unsaturated fatty acids of different chain lengths and/or configurations, and the radiation damage to K + -permeability of the resulting modified cells was investigated in relation with factors influencing membrane fluidity, such as temperature and procaine. Radiation had greater effects on membranes supplemented with unsaturated fatty acids of the trans configuration with a longer chain than on those of the cis configuration with a shorter chain. Radiation damage also increased with decrease in temperature. Furthermore, procaine-treated membranes showed increased resistance to radiation. All these results indicate that the damage was affected by the physical character of membrane lipids and that it was greater in membranes with decreased fluidity. (author)

  18. An investigation of the damaged zone created by perforating

    International Nuclear Information System (INIS)

    Pucknell, J.K.; Behrmann, L.A.

    1991-01-01

    This paper reports on underbalance perforation flow experiments performed on reservoir and outcrop sandstones to investigate the perforation damaged zone. Cores from several different formations were perforated under reservoir conditions. After perforating, the cores were examined using CAT scans (Computer Aided tomography), thin sections and mercury porosimetry. In conjunction with these measurements, permeabilities in the damaged zone were measured using a minipermeameter and radial flow permeameter or were estimated from pore size distribution. The density and porosity of the damaged zone (at least for saturated rocks) is essentially the same as that in the undamaged rock. The damaged zone is not compacted, contrary to suggestions made in earlier work. However, the creation of this zone involves the destruction of large pores. The volume lost from these pores is replaced by microfractures created when rock grains are fractured by penetration of the shaped charge jet. This reduction in the average pore size causes a reduction in the permeability with the damaged zone. Although direct measurement of this permeability was made difficult by naturally occurring permeability variations, unambiguous measurements were obtained

  19. A Simplified Algorithm for Statistical Investigation of Damage Spreading

    International Nuclear Information System (INIS)

    Gecow, Andrzej

    2009-01-01

    On the way to simulating adaptive evolution of complex system describing a living object or human developed project, a fitness should be defined on node states or network external outputs. Feedbacks lead to circular attractors of these states or outputs which make it difficult to define a fitness. The main statistical effects of adaptive condition are the result of small change tendency and to appear, they only need a statistically correct size of damage initiated by evolutionary change of system. This observation allows to cut loops of feedbacks and in effect to obtain a particular statistically correct state instead of a long circular attractor which in the quenched model is expected for chaotic network with feedback. Defining fitness on such states is simple. We calculate only damaged nodes and only once. Such an algorithm is optimal for investigation of damage spreading i.e. statistical connections of structural parameters of initial change with the size of effected damage. It is a reversed-annealed method--function and states (signals) may be randomly substituted but connections are important and are preserved. The small damages important for adaptive evolution are correctly depicted in comparison to Derrida annealed approximation which expects equilibrium levels for large networks. The algorithm indicates these levels correctly. The relevant program in Pascal, which executes the algorithm for a wide range of parameters, can be obtained from the author.

  20. Radiation damage in silicon. Defect analysis and detector properties

    International Nuclear Information System (INIS)

    Hoenniger, F.

    2008-01-01

    Silicon microstrip and pixel detectors are vital sensor-components as particle tracking detectors for present as well as future high-energy physics (HEP) experiments. All experiments at the large Hadron Collider (LHC) are equipped with such detectors. Also for experiments after the upgrade of the LHC (the so-called Super-LHC), with its ten times higher luminosity, or the planned International Linear Collider (ILC) silicon tracking detectors are forseen. Close to the interaction region these detectors have to face harsh radiation fields with intensities above the presently tolerable level. defect engineering of the used material, e. g. oxygen enrichment of high resistivity float zone silicon and growing of thin low resistivityepitaxial layers on Czochralski silicon substrates has been established to improve the radiation hardness of silicon sensors. This thesis focuses mainly on the investigation of radiation induced defects and their differences observed in various kinds of epitaxial silicon material. Comparisons with other materials like float zone or Czochralski silicon are added. Deep Level Transient Spectroscopy (DLTS) and Thermally Stimulated Current (TSC) measurements have been performed after γ-, electron-, proton- and neutron-irradiation. The differenced in the formation of vacancy and interstitial related defects as well as so-called clustered regions were investigated for various types of irradiation. In addition to the well known defects VO i , C i O i , C i C s , VP or V 2 several other defect complexes have been found and investigated. Also the material dependence of the defect introduction rates and the defect annealing behavior has been studied by isothermal and isochronal annealing experiments. Especially the IO 2 defect which is an indicator for the oxygen-dimer content of the material has been investigated in detail. On the basis of radiation induced defects like the bistable donor (BD) defect and a deep acceptor, a model has been introduced to

  1. Radiation damage in silicon. Defect analysis and detector properties

    Energy Technology Data Exchange (ETDEWEB)

    Hoenniger, F.

    2008-01-15

    Silicon microstrip and pixel detectors are vital sensor-components as particle tracking detectors for present as well as future high-energy physics (HEP) experiments. All experiments at the large Hadron Collider (LHC) are equipped with such detectors. Also for experiments after the upgrade of the LHC (the so-called Super-LHC), with its ten times higher luminosity, or the planned International Linear Collider (ILC) silicon tracking detectors are forseen. Close to the interaction region these detectors have to face harsh radiation fields with intensities above the presently tolerable level. defect engineering of the used material, e. g. oxygen enrichment of high resistivity float zone silicon and growing of thin low resistivityepitaxial layers on Czochralski silicon substrates has been established to improve the radiation hardness of silicon sensors. This thesis focuses mainly on the investigation of radiation induced defects and their differences observed in various kinds of epitaxial silicon material. Comparisons with other materials like float zone or Czochralski silicon are added. Deep Level Transient Spectroscopy (DLTS) and Thermally Stimulated Current (TSC) measurements have been performed after {gamma}-, electron-, proton- and neutron-irradiation. The differenced in the formation of vacancy and interstitial related defects as well as so-called clustered regions were investigated for various types of irradiation. In addition to the well known defects VO{sub i}, C{sub i}O{sub i}, C{sub i}C{sub s}, VP or V{sub 2} several other defect complexes have been found and investigated. Also the material dependence of the defect introduction rates and the defect annealing behavior has been studied by isothermal and isochronal annealing experiments. Especially the IO{sub 2} defect which is an indicator for the oxygen-dimer content of the material has been investigated in detail. On the basis of radiation induced defects like the bistable donor (BD) defect and a deep

  2. Radiation Damage and Fission Product Release in Zirconium Nitride

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-08-29

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

  3. Investigation of cutting-induced damage in CMC bend bars

    Directory of Open Access Journals (Sweden)

    Neubrand A.

    2015-01-01

    Full Text Available Ceramic matrix composites (“CMC” with a strong fibre-matrix interface can be made damage-tolerant by introducing a highly porous matrix. Such composites typically have only a low interlaminar shear strength, which can potentially promote damage when preparing specimens or components by cutting. In order to investigate the damage induced by different cutting methods, waterjet cutting with and without abrasives, laser-cutting, wire eroding and cutoff grinding were used to cut plates of two different CMCs with a matrix porosity up to 35 vol.-%. For each combination of cutting method and composite, the flexural and interlaminar shear strength of the resulting specimens was determined. Additionally, the integrity of the regions near the cut surfaces was investigated by high-resolution x-ray computer tomography. It could be shown that the geometrical quality of the cut is strongly affected by the cutting method employed. Laser cut and waterjet cut specimens showed damage and delaminations near the cut surface leading to a reduced interlaminar shear strength of short bend bars in extreme cases.

  4. Multi-scale approach to radiation damage induced by ion beams: complex DNA damage and effects of thermal spikes

    International Nuclear Information System (INIS)

    Surdutovich, E.; Yakubovich, A.V.; Solov'yov, A.V.; Surdutovich, E.; Yakubovich, A.V.; Solov'yov, A.V.

    2010-01-01

    We present the latest advances of the multi-scale approach to radiation damage caused by irradiation of a tissue with energetic ions and report the calculations of complex DNA damage and the effects of thermal spikes on biomolecules. The multi-scale approach aims to quantify the most important physical, chemical, and biological phenomena taking place during and following irradiation with ions and provide a better means for clinically-necessary calculations with adequate accuracy. We suggest a way of quantifying the complex clustered damage, one of the most important features of the radiation damage caused by ions. This quantification allows the studying of how the clusterization of DNA lesions affects the lethality of damage. We discuss the first results of molecular dynamics simulations of ubiquitin in the environment of thermal spikes, predicted to occur in tissue for a short time after an ion's passage in the vicinity of the ions' tracks. (authors)

  5. Radiation damage and defects in NPN bipolar junction transistors irradiated by silicon ions with various energies

    Science.gov (United States)

    Liu, Chaoming; Zhang, Xiaodong; Yang, Jianqun; Li, Xingji; Ma, Guoliang

    2017-10-01

    The characteristic of incident particle is an important factor to evaluate the correlation of radiation damage. It is useful to investigate the influence of incident particle with various energies on radiation effects of BJTs. Radiation effects in bipolar junction transistors are examined under the irradiation with 10, 24 and 40 MeV Si ions in this paper. Based on the electrical performance degradation, it is shown that the change in the reciprocal of current gain is dominated by the ionizing damage during the heavy ion irradiations at low fluence, leading to a non-linear behavior. While at a higher fluence, displacement damage is the domain effect to show a linear curve. Deep level transient spectroscopy (DLTS) is used to analyze the characteristic of the deep level defects induced by irradiations. DLTS results show that for the BJTs under various Si ions irradiations, the types of deep level defects induced by Si ions are similar, while the concentration of the defects is different at the same displacement dose.

  6. Influence of Hot Implantation on Residual Radiation Damage in Silicon Carbide

    International Nuclear Information System (INIS)

    Rawski, M.; Zuk, J.; Kulik, M.; Drozdziel, A.; Pyszniak, K.; Turek, M.; Lin, L.; Prucnal, S.

    2011-01-01

    Remarkable thermomechanical and electrical properties of silicon carbide (SiC) make this material very attractive for high-temperature, high-power, and high-frequency applications. Because of very low values of diffusion coefficient of most impurities in SiC, ion implantation is the best method to selectively introduce dopants over well-defined depths in SiC. Aluminium is commonly used for creating p-type regions in SiC. However, post-implantation radiation damage, which strongly deteriorates required electric properties of the implanted layers, is difficult to anneal even at high temperatures because of remaining residual damage. Therefore implantation at elevated target temperatures (hot implantation) is nowadays an accepted method to decrease the level of the residual radiation damage by avoiding ion beam-induced amorphization. The main objective of this study is to compare the results of the Rutherford backscattering spectroscopy with channeling and micro-Raman spectroscopy investigations of room temperature and 500 o C Al + ion implantation-induced damage in 6H-SiC and its removal by high temperature (up to 1600 o C) thermal annealing. (author)

  7. Grape (Vitis vinifera) extracts protect against radiation-induced oxidative stress and DNA damage

    International Nuclear Information System (INIS)

    Singha, Indrani; Das, Subir Kumar; Saxena, S.; Gautam, S.

    2016-01-01

    Ionizing radiation (IR) causes oxidative stress through the overwhelming generation of reactive oxygen species (ROS) in the living cells leading further to the oxidative damage to biomolecules. Grapes (Vitis vinifera) contain several bioactive phytochemicals and are the richest source of antioxidant. In this study, we investigated and compared in vitro antioxidant activity and DNA damage protective property of the grape extracts of four different cultivars, including the Thompson seedless, Flame seedless, Kishmish chorni and Red globe. The activities of ascorbic acid oxidase and catalase significantly (p<0.01) differed among extracts within the same cultivar, while that of peroxidase and polyphenol oxidase did not differ significantly among extracts of any cultivar. In vitro antioxidant activities were assessed by ferric-reducing antioxidant power (FRAP) assay and ABTS. The superoxide radical-scavenging activity was higher in the seed as compared to the skin or pulp of the same cultivar. DNA damage was evaluated in acellular system using pBR322 plasmid relaxation. Grape extract was able to effectively scavenge free radicals in vitro. It could significantly prevent radiation-induced DNA damage. Furthermore, the protective action of grape depends on the source of extract and type of the cultivars. (author)

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

    Science.gov (United States)

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

    2015-12-01

    Over the past decade people have been constantly exposed to microwave radiation mainly from wireless communication devices used in day to day life. Therefore, the concerns over potential adverse effects of microwave radiation on human health are increasing. Until now no study has been proposed to investigate the underlying causes of genotoxic effects induced by low intensity microwave exposure. Thus, the present study was undertaken to determine the influence of low intensity microwave radiation on oxidative stress, inflammatory response and DNA damage in rat brain. The study was carried out on 24 male Fischer 344 rats, randomly divided into four groups (n=6 in each group): group I consisted of sham exposed (control) rats, group II-IV consisted of rats exposed to microwave radiation at frequencies 900, 1800 and 2450 MHz, specific absorption rates (SARs) 0.59, 0.58 and 0.66 mW/kg, respectively in gigahertz transverse electromagnetic (GTEM) cell for 60 days (2h/day, 5 days/week). Rats were sacrificed and decapitated to isolate hippocampus at the end of the exposure duration. Low intensity microwave exposure resulted in a frequency dependent significant increase in oxidative stress markers viz. malondialdehyde (MDA), protein carbonyl (PCO) and catalase (CAT) in microwave exposed groups in comparison to sham exposed group (pmicrowave exposed groups (pmicrowave exposed animal (pmicrowave exposed groups as compared to their corresponding values in sham exposed group (pmicrowave radiation induces oxidative stress, inflammatory response and DNA damage in brain by exerting a frequency dependent effect. The study also indicates that increased oxidative stress and inflammatory response might be the factors involved in DNA damage following low intensity microwave exposure. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. A FLUORESCENCE BASED ASSAY FOR DNA DAMAGE: INDUCED BY RADIATION, CHEMICALS AND ENZYMES

    Science.gov (United States)

    A simple and rapid assay to detect DNA damage is reported. This assay is based on the ability of certain dyes to fluoresce upon intercalation with dsDNA. Damage caused by ultraviolet (UV) radiation, chemicals or restriction enzymes is detected using this assay. UV radiation at...

  10. Radiation damage studies related to nuclear waste forms

    International Nuclear Information System (INIS)

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

    1981-12-01

    Much of the previously reported work on alpha radiation effects on crystalline phases of importance to nuclear waste forms has been derived from radiation effects studies of composite waste forms. In the present work, two single-phase crystalline materials, Gd 2 Ti 2 O 7 (pyrochlore) and CaZrTi 2 O 7 (zirconolite), of relative importance to current waste forms were studied independently by doping with 244 Cm at the 3 wt % level. Changes in the crystalline structure measured by x-ray diffraction as a function of dose show that damage ingrowth follows an expected exponential relationship of the form ΔV/V 0 = A[1-exp(-BD)]. In both cases, the materials became x-ray amorphous before the estimated saturation value was reached. The predicted magnitudes of the unit cell volume changes at saturation are 5.4% and 3.5%, respectively, for Gd 2 Ti 2 O 7 and CaZrTi 2 O 7 . The later material exhibited anisotropic behavior in which the expansion of the monoclinic cell in the c 0 direction was over five times that of the a 0 direction. The effects of transmutations on the properties of high-level waste solids have not been studied until now because of the long half-lives of the important fission products. This problem was circumvented in the present study by preparing materials containing natural cesium and then irradiating them with neutrons to produce 134 Cs, which has only a 2y half-life. The properties monitored at about one year intervals following irradiation have been density, leach rate and microstructure. A small amount of x-ray diffraction work has also been done. Small changes in density and leach rate have been observed for some of the materials, but they were not large enough to be of any consequence for the final disposal of high level wastes

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

    International Nuclear Information System (INIS)

    Tsutsumi, Nobuo; Rakugi, Masami; Kusamura, Yayoi; Ochiai, Nobuyuki; Saito, Takahiro

    1983-01-01

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

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

    Science.gov (United States)

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

    2002-01-01

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

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

    International Nuclear Information System (INIS)

    Garcia Celma, A.

    1993-12-01

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

  14. Neutron dosimetry for radiation damage in fission and fusion reactors

    International Nuclear Information System (INIS)

    Smith, D.L.

    1979-01-01

    The properties of materials subjected to the intense neutron radiation fields characteristic of fission power reactors or proposed fusion energy devices is a field of extensive current research. These investigations seek important information relevant to the safety and economics of nuclear energy. In high-level radiation environments, neutron metrology is accomplished predominantly with passive techniques which require detailed knowledge about many nuclear reactions. The quality of neutron dosimetry has increased noticeably during the past decade owing to the availability of new data and evaluations for both integral and differential cross sections, better quantitative understanding of radioactive decay processes, improvements in radiation detection technology, and the development of reliable spectrum unfolding procedures. However, there are problems caused by the persistence of serious integral-differential discrepancies for several important reactions. There is a need to further develop the data base for exothermic and low-threshold reactions needed in thermal and fast-fission dosimetry, and for high-threshold reactions needed in fusion-energy dosimetry. The unsatisfied data requirements for fission reactor dosimetry appear to be relatively modest and well defined, while the needs for fusion are extensive and less well defined because of the immature state of fusion technology. These various data requirements are examined with the goal of providing suggestions for continued dosimetry-related nuclear data research

  15. Scopolamine methylbromide mitigates radiation induced damage and lethality in zebrafish

    International Nuclear Information System (INIS)

    Shrivastava, Nitisha; Joshi, Jayadev; Ghosh, Subhajit; Dimri, Manali; Prem Kumar, Indracanti; Sehgal, Neeta

    2014-01-01

    In view of the strategic importance radiation countermeasures hold, the present study was undertaken to screen a collection of small molecule clinical compounds for possible radioprotective action using zebrafish as a model system. Preliminary screening in developing zebrafish embryos (24 hour post fertilization, (hpf)) using damage manifestations and survival as end point identified scopolamine methylbromide (SMB), a muscarinic receptor antagonist, as a potential radiomitigator. It was found to be optimal (60% survival advantage after 6 th post irradiation day) at a dose of 80 μM when added 3 h post 20 Gy exposure. Mechanistic studies suggested that SMB though exhibited no significant antioxidant potential, but was found to limit radiation induced apoptosis (pre G1 population) quantified through flow cytometry (6 and 5% reduction after 8 or 24 h after treatments) and annexin V staining (8% reduction). Further, quantitative analysis, using caspase 3 assay, revealed a 2.46 fold increase in apoptosis in irradiated group and treatment of irradiated zebrafish embryos with SMB led to a significant reduction in global apoptosis (1.7 fold; p<0.05) when compared to irradiated group. In silico studies based on structural and functional similarity with known radioprotectors suggested similarities with atropine, a known anti-inflammatory agent with muscarinic antagonism and radioprotective potential. In view of this SMB was tested, in silico, for possible anti-inflammatory action. Molecular docking studies revealed that SMB interacts (B.E-8.0 Kcal/mole) with cycloxygenase-2 (COX-2). In lieu of this, anti-inflammation activity was assessed through ChIN (chemically induced inflammation) method in 3 dpf (days post fertilization) embryos and SMB was found to significantly inhibit inflammation at all doses studied from 20-200 μM at 3 and 6 hpi (hours post inflammation). Overall the result suggests that scopolamine methylbromide mitigates radiation induced injury and lethality in

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-03-01

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

  17. Radiation damage in diatomic materials at high doses

    International Nuclear Information System (INIS)

    Hobbs, L.W.; Hughes, A.E.

    1975-10-01

    Radiation effects in diatomic materials can differ structurally from those in metals because of the need to take into account different displacement rates on the two sublattices and the inevitable stoichiometric implications; in most diatomic insulators the anion species has the greater displacement cross section. Anion point defect stabilisation in heavily-irradiated (0.1 to 10 dpa) diatomic insulators has been studied using radiolysis of alkali and alkaline earth halides. A temperatures > 0.3 Tsub(m), all anion defects are mobile and can aggregate. Aggregation of anion interstitials results in creation of perfect dislocation loops without the need for primary cation displacements; simultaneous formation of substitutional anion molecular centres provides the necessary cation interstitials. Aggregation of anion vacancies leads to formation of metallic inclusions of the cation species, in some cases in an ordered array, which is the analogue, on a single sublattice, to the void lattice in metals. Availability of sinks for both anion interstitials and anion vacancies yields defect growth kinetics similar to those observed during formation of voids in irradiated metals, and a very high level of damage (approximately 10%) can be sustained in the lattice. The width of the temperature region concerned is much narrower, however, due to the possibility of recombination of aggregated or re-emitted anion vacancies with mobile or dispersed anion molecular defects; the latter can also aggregate to form fluid anion molecular inclusions and so complete the decomposition of the solid into separate phases of its constituent elements. (author)

  18. A novel theory of radiation damage at high doses

    International Nuclear Information System (INIS)

    Seeger, A.; Stuttgart Univ.

    1989-01-01

    Deviations of radiation damage (in the case of metals usually monitored by the residual electrical resistivity) from proportionality with the irradiation dose have so far been analysed almost exclusively in terms of extensions of models originally developed for small doses. The present theory considers the opposite limit i.e. the quasi-saturated state. It is argued that at high doses the Lueck-Sizmann effect may result in a self-organization of clusters of vacancies and self-interstitials, forming a heterogeneous froth. Possible structures of this froth and its effect on the electrical resistivity of metals are discussed. The model is shown to account for the dependence of the ''saturation resistivity'' on the nature of the irradiation as well as for several other hitherto poorly explained observations. Among them are the electrical-resistivity variation induced by high-dose irradiation with heavy ions, the amorphization of certain alloys by high-dose electron irradiation, and the occurrence of ordered arrays of stacking-fault tetrahedra after in-situ irradiations in high-voltage electron microscopes. (author)

  19. Monitoring radiation damage in the LHCb Silicon Tracker

    CERN Multimedia

    Graverini, Elena

    2018-01-01

    The purpose of LHCb is to search for indirect evidence of new physics in decays of heavy hadrons. The LHCb detector is a single-arm forward spectrometer with precise silicon-strip detectors in the regions with highest particle occupancies. The non-uniform exposure of the LHCb sensors makes it an ideal laboratory to study radiation damage effects in silicon detectors. The LHCb Silicon Tracker is composed of an upstream tracker, the TT, and of the inner part of the downstream tracker (IT). Dedicated scans are regularly taken, which allow a precise measurement of the charge collection efficiency (CCE) and the calibration of the operational voltages. The measured evolution of the effective depletion voltage $V_{depl}$ is shown, and compared with the Hamburg model prediction. The magnitudes of the sensor leakage current are also analysed and compared to their expected evolution according to phenomenological models. Our results prove that both the TT and the IT will withstand normal operation until the end of the L...

  20. Characterization of ionizing radiation damage in DNA. Progress report, May 1, 1975--April 30, 1976

    International Nuclear Information System (INIS)

    Hawkins, R.B.

    1976-01-01

    The objective of this research is the characterization and quantitative assay of ionizing radiation-induced damage in DNA and nucleoprotein. Two lines of investigation have been pursued. The first is aimed at detection and assay of DNA to protein covalent cross linkage in coliphage T7. Protein and DNA are labeled with 14 C and 32 P, respectively. Cross linkage is assessed from the amount of labeled protein distributing like DNA and labeled DNA distributing like protein on a phenol-water countercurrent distribution system. It has been found that damage involving cross linkage occurs by two modes of radiation action in phage irradiated with 60 Co γ rays in .001M histidine medium. Indirect effects play a large role in one mode and direct effects play a large role in the other. In the second line of investigation, the hydrodynamic and viscoelastic properties of DNA from irradiated phage and cells will be examined to determine the extent to which DNA to DNA cross linkage and points of altered flexibility are introduced by radiation. An instrument for viscoelastic measurements has been constructed in preparation for these studies

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

    Science.gov (United States)

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

    2016-07-01

    The radiation damage and microstructure evolution of different zigzag single-walled carbon nanotubes (SWCNTs) were investigated under incident carbon ion by molecular dynamics (MD) simulations. The radiation damage of SWCNTs under incident carbon ion with energy ranging from 25 eV to 1 keV at 300 K showed many differences at different incident sites, and the defect production increased to the maximum value with the increase in incident ion energy, and slightly decreased but stayed fairly stable within the majority of the energy range. The maximum damage of SWCNTs appeared when the incident ion energy reached 200 eV and the level of damage was directly proportional to incident ion fluence. The radiation damage was also studied at 100 K and 700 K and the defect production decreased distinctly with rising temperature because radiation-induced defects would anneal and recombine by saturating dangling bonds and reconstructing carbon network at the higher temperature. Furthermore, the stability of a large-diameter tube surpassed that of a thin one under the same radiation environments.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-04-01

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

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

    International Nuclear Information System (INIS)

    Cho, Chul Koo; Kim, Tae Hwan; Lee, Yun Sil

    2000-04-01

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

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

    International Nuclear Information System (INIS)

    Geras'kin, S.A.; Dikarev, V.G.; Nesterov, E.B.; Vasiliev, D.V.; Dikareva, N.S.

    2000-01-01

    radioactive wastes located at Sosnovy Bor in the Leningrad region was carried out in 1995-1999. Results of this research give evidence on pronounced genotoxic influence presence in investigated sites and as against the 30-km ChNPP zone in the Sosnovy Bor region chemical toxicants make the significant contribution to pollution of the environment. The seeds collected in control and experimental population were compared by acute γ-irradiation resistance. This comparison has revealed the selection toward the increase of repair system efficiency. The received results give evidence that although the cytogenetic damage frequency within low dose range cannot be used in biological dosimetry, but the indexes based on it are informative and important for the man-made effect bioindication and for identification of groups at risk of long term health consequences of radiation. (author)

  5. Modulation of radiation induced DNA damage by natural products in hemopoietic tissue of mice

    International Nuclear Information System (INIS)

    Jayakumar, S.; Bhilwade, H.N.; Chaubey, R.C.

    2014-01-01

    Ionizing radiation is known to induce oxidative stress through generation of ROS leading to a variety of DNA lesions. However, the most dangerous DNA lesions which are responsible for the origin of lethal effects, mutagenesis, genomic instability and carcinogenesis are the DSBs. During recent years efforts are being made to identify phytochemicals, antioxidants or neutraxeuticals which can reduce harmful effect of radiation during accidental exposure or prevent normal tissue injury during radiotherapy. In the present study, we have investigated the radioprotective role of curcumin, a dietary antioxidant, taurine, malabaricone-C, and umbelliferone, for their radioprotective properties in hemopoietic cells of mice. Groups of mice-were fed 1% of curcumin in diet for three weeks. Similarly other groups of mice were injected i.p. with 50 mg/kg body weight of taurine for five consecutive days. After the completion of the treatment mice pre-treated with curcumin and taurine were exposed to 3 Gy of gamma rays. Malabaricone-C was tested for its radiomodulation potential in vitro, in spleenocytes of mouse. Spleenocytes were isolated and treated with different concentrations (0.5-25 ìM) of malabaricone-C. Immediately after irradiation, alkaline comet assay were performed using standard procedures. Twenty four post radiation exposure mice were sacrificed for micronucleus test. Results of these studies showed significant reduction in DNA damage by curcumin. The micronucleus data showed marginal increase in the frequency of micronucleated erythrocytes in curcumin fed group as compared to the controls. Mice receiving curcumin for 3 weeks in diet followed by gamma radiation (3 Gy), showed approximately 50% reduction in the frequency of micro nucleated polychromatic erythrocytes. Pre-treatment of mice with taurine significantly (p < 0.01) reduced the frequency of gamma rays induced mn-PCEs in bone marrow tissue. Malabaricone-C at 1.5 ìM concentration showed very good protection

  6. Post-irradiation dietary vitamin E does not affect the development of radiation-induced lung damage in rats

    NARCIS (Netherlands)

    Wiegman, EA; van Gameren, MA; Kampinga, HH; Szabo, BG; Coppes, RP

    The purpose of this study was to investigate whether application of post-irradiation vitamin E, an anti-oxidant, could prevent the development of radiation induced lung damage. Wistar rats were given vitamin E enriched or vitamin E deprived food starting from 4 weeks after 18 Gy single dose

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

    CERN Document Server

    Colombo, M

    1998-01-01

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

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

    International Nuclear Information System (INIS)

    Colombo, M.; Chrosch, J.

    1998-01-01

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

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

    International Nuclear Information System (INIS)

    Said, U.Z.; Saada, H.N.; Shedid, Sh.M.; Mahdy, E.M.E.; Shousha, W.Gh.

    2008-01-01

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

  10. Nondestructive Investigation of Stress-Induced Damage in Concrete

    Directory of Open Access Journals (Sweden)

    P. Shokouhi

    2010-01-01

    Full Text Available The changes in the sonic surface wave velocity of concrete under stress were investigated in this paper. Surface wave velocities at sonic frequency range were measured on a prismatic concrete specimen undergoing several cycles of uniaxial compression. The loading was applied (or removed gradually in predefined small steps (stress-controlled. The surface wave velocity was measured at every load step during both loading and unloading phases. Acoustic Emission (AE test was conducted simultaneously to monitor the microcracking activities at different levels of loading. It was found that the sonic surface wave velocity is highly stress dependent and the velocity-stress relationship follows a particular trend. The observed trend could be explained by a combination of acoustoelasticity and microcracking theories, each valid over a certain range of applied stresses. Having measured the velocities while unloading, when the material suffers no further damage, the effect of stress and damage could be differentiated. The slope of the velocity-stress curves over the elastic region was calculated for different load cycles. This quantity was normalized to yield a dimensionless nonlinear parameter. This parameter generally increases with the level of induced damage in concrete.

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

    NARCIS (Netherlands)

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

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-07-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Nomura, Shinji [Department of Nuclear Engineering, Kyoto University, Kyoto 615-8530 (Japan); Tsuchida, Hidetsugu, E-mail: tsuchida@nucleng.kyoto-u.ac.jp [Department of Nuclear Engineering, Kyoto University, Kyoto 615-8530 (Japan); Quantum Science and Engineering Center, Kyoto University, Uji 611-0011 (Japan); Furuya, Ryosuke [Department of Nuclear Engineering, Kyoto University, Kyoto 615-8530 (Japan); Majima, Takuya; Itoh, Akio [Department of Nuclear Engineering, Kyoto University, Kyoto 615-8530 (Japan); Quantum Science and Engineering Center, Kyoto University, Uji 611-0011 (Japan)

    2016-12-15

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

  14. Comparison of damage induced by mercury chloride and ionizing radiation in the susceptible rat model

    International Nuclear Information System (INIS)

    Kim, Ji Hyang; Yoon, Yong Dal; Kim, Jin Kyu

    2003-01-01

    Mercury (Hg), one of the most diffused and hazardous organ-specific environmental contaminants, exists in a wide variety of physical and chemical states. Although the reports indicate that mercury induces a deleterious damage, little has been reported from the investigations of mercury effects in living things. The purpose of this study is to evaluate the effects of mercury chloride and ionizing radiation. Prepubertal male F-344 rats were administered mercury chloride in drinking water throughout the experimental period. Two weeks after whole body irradiation, organs were collected for measuring the induced injury. Serum levels of GOT, GPT, ALP, and LDH were checked in the experimental groups and the hematological analysis was accomplished in plasma. In conclusion, the target organ of mercury chloride seems to be urinary organs and the pattern of damage induced by mercury differs from that of the irradiated group

  15. Radiation damage in Fe-Cr alloys: Atomistic studies

    International Nuclear Information System (INIS)

    Terentyev, Dmitry; Malerba, Lorenzo; Bonny, Giovanni; Castin, Nicolas

    2009-01-01

    High-Cr ferritic-martensitic steels are the most promising candidate structural materials for future advanced fission reactors, as well as for fusion systems, due to their better thermomechanical properties and higher radiation resistance as compared to austenitic steels. The performance of these steels, especially under irradiation, appears to be largely determined by the Cr content. For instance, the current choice of steel compositions around ∼9 wt% Cr is mainly based on the observation of a local minimum in the ductile-brittle transition temperature shift at this composition. On the other hand, reduced void swelling is observed between 3 and 12 wt% Cr. The origin of these and other Cr-dependent effects remained unexplained for a long time, thereby calling for a physical modelling effort addressing these questions. In this presentation, an overview is given on the effort made in recent years to construct a whole modelling framework, from ab initio to dislocations, to provide explanations to the above-mentioned issues. Ab initio calculations combined to the development of the interatomic potentials capable of grasping key features of Cr atoms embedded in perfect and defected Fe matrix, were required. Primary damage, defect migration, Cr mass transport, phase separation, Cr-defect segregation and dislocation-defect interactions could then be studied using fully atomistic approaches. Our research shows that many of the effects of Cr content on the behaviour of these alloys under irradiation can be attributed to the only recently highlighted high solubility of Cr in Fe (∼10 wt%), below which, in addition, Cr atoms tend to order. The presentation will clarify how this aspect, combined with the high affinity between Cr atoms and self-interstitials defects, influences and partly explain both microstructure evolution and mechanical behaviour of high-Cr steels under irradiation. (author)

  16. Detection of Low Level Microwave Radiation Induced Deoxyribonucleic Acid Damage Vis-à-vis Genotoxicity in Brain of Fischer Rats

    Science.gov (United States)

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

    2013-01-01

    Background: Non-ionizing radiofrequency radiation has been increasingly used in industry, commerce, medicine and especially in mobile phone technology and has become a matter of serious concern in present time. Objective: The present study was designed to investigate the possible deoxyribonucleic acid (DNA) damaging effects of low-level microwave radiation in brain of Fischer rats. Materials and Methods: Experiments were performed on male Fischer rats exposed to microwave radiation for 30 days at three different frequencies: 900, 1800 and 2450 MHz. Animals were divided into 4 groups: Group I (Sham exposed): Animals not exposed to microwave radiation but kept under same conditions as that of other groups, Group II: Animals exposed to microwave radiation at frequency 900 MHz at specific absorption rate (SAR) 5.953 × 10−4 W/kg, Group III: Animals exposed to 1800 MHz at SAR 5.835 × 10−4 W/kg and Group IV: Animals exposed to 2450 MHz at SAR 6.672 × 10−4 W/kg. At the end of the exposure period animals were sacrificed immediately and DNA damage in brain tissue was assessed using alkaline comet assay. Results: In the present study, we demonstrated DNA damaging effects of low level microwave radiation in brain. Conclusion: We concluded that low SAR microwave radiation exposure at these frequencies may induce DNA strand breaks in brain tissue. PMID:23833433

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-03-15

    Captopril (angiotension converting enzyme inhibitor) is known to have a radioprotective effect in the lungs, intestines and skin, but its effect in the heart is unclear. To investigate the radioprotective effect and mechanism of captopril in the heart, the histopathological changes and immunohistochemical stains were compared with radiation alone, and radiation combined with captopril, in the rats. The histopathological changes and immunohistochemical stains (TNF {alpha} , TGF {beta} 1, PDGF and FGF2) were examined in the radiation alone and the combined captopril and radiation groups, 2 and 8 weeks after irradiation. Each group consisted of 8 to 10 rats (Sprague-Dawley). Irradiation (12.5 Gy) was given to the left hemithorax in a single fraction. Captopril (50 mg/Kg/d) mixed with water, was given orally and continuously from the first week prior to, up to the 8th week of the experiment. In the radiation alone group, the ventricle at 2 weeks after irradiation showed prominent edema ({rho} = 0.082) and fibrin deposit ({rho} = 0.018) compared to the control group. At 8 weeks, the edema was decreased and fibrosis increased compared to those at 2 weeks. The histopathological changes of the combined group were similar to those of the control group, due to the reduced radiation toxicity at 2 and 8 weeks. The endocardial fibrin deposit ({rho} = 0.047) in the atrium, and the interstitial fibrin deposit ({rho} = 0.019) and edema ({rho} = 0.042) of the ventricle were reduced significantly in the combined group compared to those in the radiation alone group at 2 weeks. The expressions of TNF- {alpha} , TGF- {beta} 1, PDGF and FGF-2 in the radiation alone group were more increased than in the control group, especially in the pericardium and endocardium of the atrium at 2 weeks. At 8 weeks, the pericardial TNF- {alpha} and TGF- {beta} 1, in the radiation alone group continuously increased. The expressions of TNF- {alpha} , TGF- {beta} 1, and PDGF were decreased in the combined

  18. Investigation of Magnetospheric Line Radiation above China

    Science.gov (United States)

    Sheng, X.; Wu, J.; Pu, X.

    2017-12-01

    Magnetospheric Line Radiation (MLR) is a kind of VLF emission that is considered by some researchers to be related with the power system on ground, and in frequency-time spectrograms of electromagnetic field, it has a line structure with large frequency bandwidth. These emission waves propagate through the magnetosphere and strongly interact with energetic electrons trapped in the earth's magnetic field. Such a wave-particle interaction amplifies the radiation and scatters energetic electrons, which may trigger new radiations. We detected 328 MLR events by analyzing the electric field data observed by DEMETER satellite in the space above China from the year of 2008 to 2010. Their characteristics and possible cause have been investigated systematically. There were more MLR events in daytime than in nighttime and more in winter than in summer. Such diurnal and seasonal differences were closely associated with whistlers and ionosphere conditions. Comparing Kp indices at the occurring time of MLR events and nationwide Kp indices through the analyzed years, we found these MLR events were not significantly dependent on geomagnetic activity. Most of events were distributed in the low latitude, while their peak intensities in frequency-time spectrograms seemed to be independent of latitude. The frequency intervals of MLR events were between 50 to 95Hz, and the frequency drifts were mostly in 0 0.4Hz/s. The above characteristics of MLR events were similar to those of Power Line Harmonic Radiation (PLHR) events observed in the space above China, therefore we inferred that these two emissions have close relation.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-10-15

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

  20. Analysis of ionizing radiation-induced foci of DNA damage repair proteins

    International Nuclear Information System (INIS)

    Veelen, Lieneke R. van; Cervelli, Tiziana; Rakt, Mandy W.M.M. van de; Theil, Arjan F.; Essers, Jeroen; Kanaar, Roland

    2005-01-01

    Repair of DNA double-strand breaks by homologous recombination requires an extensive set of proteins. Among these proteins are Rad51 and Mre11, which are known to re-localize to sites of DNA damage into nuclear foci. Ionizing radiation-induced foci can be visualized by immuno-staining. Published data show a large variation in the number of foci-positive cells and number of foci per nucleus for specific DNA repair proteins. The experiments described here demonstrate that the time after induction of DNA damage influenced not only the number of foci-positive cells, but also the size of the individual foci. The dose of ionizing radiation influenced both the number of foci-positive cells and the number of foci per nucleus. Furthermore, ionizing radiation-induced foci formation depended on the cell cycle stage of the cells and the protein of interest that was investigated. Rad51 and Mre11 foci seemed to be mutually exclusive, though a small subset of cells did show co-localization of these proteins, which suggests a possible cooperation between the proteins at a specific moment during DNA repair

  1. Computer simulation of radiation damage in NaCl using a kinetic rate reaction model

    International Nuclear Information System (INIS)

    Soppe, W.J.

    1993-01-01

    Sodium chloride and other alkali halides are known to be very susceptible to radiation damage in the halogen sublattice when exposed to ionizing radiation. The formation of radiation damage in NaCl has generated interest because of the relevance of this damage to the disposal of radioactive waste in rock salt formations. In order to estimate the long-term behaviour of a rock salt repository, an accurate theory describing the major processes of radiation damage in NaCl is required. The model presented in this paper is an extended version of the Jain-Lidiard model; its extensions comprise the effect of impurities and the colloid nucleation stage on the formation of radiation damage. The new model has been tested against various experimental data obtained from the literature and accounts for several well known aspects of radiation damage in alkali halides which were not covered by the original Jain-Lidiard model. The new model thus may be expected to provide more reliable predictions for the build-up of radiation damage in a rock salt nuclear waste repository. (Author)

  2. Sestrin2 protects the myocardium against radiation-induced damage

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-05-15

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

  3. Radiation damage study using small-angle neutron scattering

    Science.gov (United States)

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

    2000-03-01

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

  4. Investigations of ultrastructure of damaged and regenerated skeletal muscle fibers.

    Science.gov (United States)

    Lańcut, Mirosław; Godlewski, Piotr; Lis-Sochocka, Marta; Visconti, Józef; Czerny, Krystyna

    2004-01-01

    Our investigations concerned the head of the parietal part of quadriceps femoris, and we based our investigation on observations of the ultrastructure of muscle fibers using an electron microscope. We observed tissue samples taken from patients (10 men) 25-35 years old, who had old damage of knee joint ligament (after about 6 week's immobilization). In the first group, segments of tissue of parietal head of quadriceps femoris were taken inter-operationally from patients in whom there was found old damage of knee joint ligament. The second group was of tissue segments of this muscle after surgical repair of knee and rehabilitation, which consisted in power training using resistance machines. The muscle fiber samples of quadriceps femoris which were taken from patients during the first operation, showed big changes in their ultrastructure. These changes included: myofibrils disintegration; disturbance of regularly arranged striation in sarcomers; dissappearance of Z line. In the sarcoplasm, we observed large vacuolisation, and in the interfibrillar spaces--an accumulation of exudate and morphotic elements of blood outside the capillary vessels. Observations of muscle tissue after regeneration, showed a big improvement in the muscle cell's ultrastructure--the myofibrils were regularly arranged, and the sarcomers striations showed no deviations from normal structure. We also observed a considerable increase in the number of properly formed ultrastructure mitochondria when compared with the first group.

  5. Photoprotection beyond ultraviolet radiation--effective sun protection has to include protection against infrared A radiation-induced skin damage.

    Science.gov (United States)

    Schroeder, P; Calles, C; Benesova, T; Macaluso, F; Krutmann, J

    2010-01-01

    Solar radiation is well known to damage human skin, for example by causing premature skin ageing (i.e. photoageing). We have recently learned that this damage does not result from ultraviolet (UV) radiation alone, but also from longer wavelengths, in particular near-infrared radiation (IRA radiation, 760-1,440 nm). IRA radiation accounts for more than one third of the solar energy that reaches human skin. While infrared radiation of longer wavelengths (IRB and IRC) does not penetrate deeply into the skin, more than 65% of the shorter wavelength (IRA) reaches the dermis. IRA radiation has been demonstrated to alter the collagen equilibrium of the dermal extracellular matrix in at least two ways: (a) by leading to an increased expression of the collagen-degrading enzyme matrix metalloproteinase 1, and (b) by decreasing the de novo synthesis of the collagen itself. IRA radiation exposure therefore induces similar biological effects to UV radiation, but the underlying mechanisms are substantially different, specifically, the cellular response to IRA irradiation involves the mitochondrial electron transport chain. Effective sun protection requires specific strategies to prevent IRA radiation-induced skin damage. 2010 S. Karger AG, Basel.

  6. Radiation damage studies on natural and synthetic rock salt utilizing measurements made during electron irradiation

    International Nuclear Information System (INIS)

    Swyler, K.J.; Levy, P.W.

    1977-01-01

    The numerous radiation damage effects which will occur in the rock salt surrounding radioactive waste disposal canisters are being investigated with unique apparatus for making optical and other measurements during 1 to 3 MeV electron irradiation. This equipment, consists of a computer controlled double beam spectrophotometer which simultaneously records 256 point absorption and radioluminescence spectra, in either the 200 to 400 or 400 to 800 nm region, every 40 seconds. Most often the measurements commence as the irradiation is started and continue after it is terminated. This procedure provides information on the kinetics and other details of the damage formation process and, when the irradiation is terminated, on both the transient and stable damage components. The exposure rates may be varied between 10 2 or 10 3 to more than 10 8 rad per hour and the sample temperature maintained between 25 and 800 or 900 0 C. Although this project was started recently, measurements have been made on synthetic NaCl and on natural rock salt from two disposal sites and two mines. Both unstrained and purposely strained samples have been used. Most recently, measurements at temperatures between 25 and 200 0 C have been started. The few measurements completed to date indicate that the damage formation kinetics in natural rock salt are quite different from those observed in synthetic NaCl

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

    International Nuclear Information System (INIS)

    Stapleton, A.E.; Walbot, V.

    1994-01-01

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

  8. Caffeine potentiates or protects against radiation-induced DNA and chromosomal damage in human lymphocytes depending on temperature and concentration

    International Nuclear Information System (INIS)

    Stoilov, L.M.; Mullenders, L.H.F.; Natarajan, A.T.

    1994-01-01

    The effect of caffeine on radiation-induced chromosomal aberrations and DNA strand breaks in unstimulated human lymphocytes was investigated. When present prior to and during the radiation exposure, caffeine treatment was found to cause either potentiation or protection against induction of chromosomal aberrations depending on the concentration and temperature. When the nucleoid sedimentation technique was applied, enhancement or reduction of radiation-induced DNA strand breaks by caffeine was also found to be dependent on temperature and caffeine concentration. It is proposed that caffeine, in addition to its suspected ability to influence DNA repair, can also influence the induction of DNA damage, leading to alterations in the yield of chromosomal aberrations

  9. Experimental investigations on chronic irradiation damage of the heart

    International Nuclear Information System (INIS)

    Lauk, S.

    1984-02-01

    Irradiation of rat hearts induced the following clinical phenomena: increasingly severe dyspnea, associated flank respiration and deterioration of the general condition bordering on a prefinal syndrome. Dissection of the sick animals and thoracal x-rays taken regularly revealed extensive pesicardial and pleural effusions. The tissue of the pericardium was thickened and edematous. The most striking histological finding consisted in a focal degeneration and destruction of the myocardium without an increase in collagenous fibres. This damage to the heart muscle was quite severe and seen in all dose groups from 15 to 40 Gy. At the same time there was a reduction of the capillary density as a function of the radiation dose. Clinical symptoms were also observed in animals irradiated with 10 Gy only. All animals irradiated with at least 20 Gy, attained a state where death was imminent. Consequently, the LD-50 must be lower than 20 Gy. The latency period was over a year at 15 Gy but decreased considerably as the dose increased. (orig.) [de

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

    International Nuclear Information System (INIS)

    Hadjidekova, V.; Hristova, R.

    2006-01-01

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

  11. Radiation damage to multi-walled carbon nanotubes and their ...

    Indian Academy of Sciences (India)

    'D band' at around 1300 cm−1 to the intensity of the 'G band' at 1590 cm−1, relative intensity of the D to G bands increases with enhancement .... different energies and doses. evolution of the D and G bands which are characteristic of ... the decrease in damage due to the drop in cross-section and the damage enhancement.

  12. Quantification of complex DNA damage by ionising radiation. An experimental and theoretical approach

    International Nuclear Information System (INIS)

    Fulford, J.

    2000-05-01

    Ionising radiation potentially produces a broad spectrum of damage in DNA including single and double strand breaks (ssb and dsb) and base damages. It has been hypothesised that sites of complex damage within cellular DNA have particular biological significance due to an associated decreased efficiency in repair. The aim of this study is to gain further understanding of the formation of complex DNA damage. Irradiations of plasmid DNA illustrate that an increase in ionising density of the radiation results in a decrease in ssb yields/Gy but an increase in dsb per ssb, indicative of an increase in the number of complex damage sites per simple isolated damage site. As the mechanism for damage formation shifts from purely indirect at low scavenging capacities to a significant proportion of direct at higher scavenging capacities the proportion of complex damage increases. Comparisons with the yields of ssb and dsb simulated by Monte-Carlo calculations for Al K USX and α-particles also indicate this correspondence. The ionisation density of low energy, secondary electrons produced by photons was assessed experimentally from the dependence of the yield of OH radicals escaping intra-track recombination on photon energy. As energy decreases the OH radical yield initially decreases reflecting an increased ionisation density. However, with further decrease in photon energy the yield of OH radicals increases in line with theoretical calculations. Base damage yields were determined for low and high ionising density radiation over a range of scavenging capacities. As scavenging capacity increases the base damage: ssb ratios increases implying a contribution from electrons to base damage. It is proposed that base damage contributes to DNA damage complexity. Complex damage analysis reveals that at cell mimetic scavenging capacities, 23% and 72% of ssb have an additional spatially close damage site following γ-ray and α-particle irradiation respectively. (author)

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  15. Use of high voltage electron microscope to simulate radiation damage by neutrons

    International Nuclear Information System (INIS)

    Mayer, R.M.

    1976-01-01

    The use of the high voltage electron microscope to simulate radiation damage by neutrons is briefly reviewed. This information is important in explaining how alloying affects void formation during neutron irradiation

  16. The use of the SRIM code for calculation of radiation damage induced by neutrons

    Science.gov (United States)

    Mohammadi, A.; Hamidi, S.; Asadabad, Mohsen Asadi

    2017-12-01

    Materials subjected to neutron irradiation will being evolve to structural changes by the displacement cascades initiated by nuclear reaction. This study discusses a methodology to compute primary knock-on atoms or PKAs information that lead to radiation damage. A program AMTRACK has been developed for assessing of the PKAs information. This software determines the specifications of recoil atoms (using PTRAC card of MCNPX code) and also the kinematics of interactions. The deterministic method was used for verification of the results of (MCNPX+AMTRACK). The SRIM (formely TRIM) code is capable to compute neutron radiation damage. The PKAs information was extracted by AMTRACK program, which can be used as an input of SRIM codes for systematic analysis of primary radiation damage. Then the Bushehr Nuclear Power Plant (BNPP) radiation damage on reactor pressure vessel is calculated.

  17. Non-Destructive Detection and Separation of Radiation Damaged Cells in Miniaturized, Inexpensive Device, Phase I

    Data.gov (United States)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-06-01

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

  19. Survey of Damage Investigation of Babbitted Industrial Bearings

    Directory of Open Access Journals (Sweden)

    Lyle A. Branagan

    2015-04-01

    Full Text Available This survey collects the efforts to understand the sources and consequences of damage to babbitted industrial bearings, which operate by means of a hydrodynamic, or hydrostatic, film. Major individual damage types are discussed in the context of major damage categories.

  20. 4-(Nitrophenylsulfonyl)piperazines mitigate radiation damage to multiple tissues.

    Science.gov (United States)

    Micewicz, Ewa D; Kim, Kwanghee; Iwamoto, Keisuke S; Ratikan, Josephine A; Cheng, Genhong; Boxx, Gayle M; Damoiseaux, Robert D; Whitelegge, Julian P; Ruchala, Piotr; Nguyen, Christine; Purbey, Prabhat; Loo, Joseph; Deng, Gang; Jung, Michael E; Sayre, James W; Norris, Andrew J; Schaue, Dörthe; McBride, William H

    2017-01-01

    Our ability to use ionizing radiation as an energy source, as a therapeutic agent, and, unfortunately, as a weapon, has evolved tremendously over the past 120 years, yet our tool box to handle the consequences of accidental and unwanted radiation exposure remains very limited. We have identified a novel group of small molecule compounds with a 4-nitrophenylsulfonamide (NPS) backbone in common that dramatically decrease mortality from the hematopoietic acute radiation syndrome (hARS). The group emerged from an in vitro high throughput screen (HTS) for inhibitors of radiation-induced apoptosis. The lead compound also mitigates against death after local abdominal irradiation and after local thoracic irradiation (LTI) in models of subacute radiation pneumonitis and late radiation fibrosis. Mitigation of hARS is through activation of radiation-induced CD11b+Ly6G+Ly6C+ immature myeloid cells. This is consistent with the notion that myeloerythroid-restricted progenitors protect against WBI-induced lethality and extends the possible involvement of the myeloid lineage in radiation effects. The lead compound was active if given to mice before or after WBI and had some anti-tumor action, suggesting that these compounds may find broader applications to cancer radiation therapy.

  1. 4-(Nitrophenylsulfonylpiperazines mitigate radiation damage to multiple tissues.

    Directory of Open Access Journals (Sweden)

    Ewa D Micewicz

    Full Text Available Our ability to use ionizing radiation as an energy source, as a therapeutic agent, and, unfortunately, as a weapon, has evolved tremendously over the past 120 years, yet our tool box to handle the consequences of accidental and unwanted radiation exposure remains very limited. We have identified a novel group of small molecule compounds with a 4-nitrophenylsulfonamide (NPS backbone in common that dramatically decrease mortality from the hematopoietic acute radiation syndrome (hARS. The group emerged from an in vitro high throughput screen (HTS for inhibitors of radiation-induced apoptosis. The lead compound also mitigates against death after local abdominal irradiation and after local thoracic irradiation (LTI in models of subacute radiation pneumonitis and late radiation fibrosis. Mitigation of hARS is through activation of radiation-induced CD11b+Ly6G+Ly6C+ immature myeloid cells. This is consistent with the notion that myeloerythroid-restricted progenitors protect against WBI-induced lethality and extends the possible involvement of the myeloid lineage in radiation effects. The lead compound was active if given to mice before or after WBI and had some anti-tumor action, suggesting that these compounds may find broader applications to cancer radiation therapy.

  2. Investigation of plasma etch induced damage in compound semiconductor devices

    Energy Technology Data Exchange (ETDEWEB)

    Shul, R.J.; Lovejoy, M.L.; Hetherington, D.L.; Rieger, D.J.; Vawter, G.A.; Klem, J.F. [Sandia National Labs., Albuquerque, NM (United States); Melloch, M.R. [Purdue Univ., Lafayette, IN (United States). School of Electrical Engineering

    1993-11-01

    We have investigated the electrical performance of mesa-isolated GaAs pn-junction diodes to determine the plasma-induced damage effects from reactive ion and reactive ion beam etching. A variety of plasma chemistries (SiCl{sub 4}, BCl{sub 3}, BCl{sub 3}/Cl{sub 2}, and Cl{sub 2}) and ion energies ranging from 100 to 400 eV were studied. We have observed that many of the RIE BCl{sub 3}/Cl{sub 2} plasmas and RIBE Cl{sub 2} plasmas yield diodes with low reverse-bias currents that are comparable to the electrical characteristics of wet-chemical-etched devices. The reverse-bias leakage currents are independent of surface morphology and sidewall profiles.

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

    International Nuclear Information System (INIS)

    Hong, Chang-Won; Lee, Joon-Ho; Kim, Suwan; Noh, Jae Myoung; Kim, Young-Mee; Pyo, Hongryull; Lee, Sunyoung

    2013-01-01

    The use of radiation therapy has been linked to an increased risk of cardiovascular disease. To understand the mechanisms underlying radiation-induced vascular dysfunction, we employed two models. First, we examined the effect of X-ray irradiation on vasodilation in rabbit carotid arteries. Carotid arterial rings were irradiated with 8 or 16 Gy using in vivo and ex vivo methods. We measured the effect of acetylcholine-induced relaxation after phenylephrine-induced contraction on the rings. In irradiated carotid arteries, vasodilation was significantly attenuated by both irradiation methods. The relaxation response was completely blocked by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, a potent inhibitor of soluble guanylate cyclase. Residual relaxation persisted after treatment with L-N ω -nitroarginine (L-NA), a non-specific inhibitor of nitric oxide synthase (NOS), but disappeared following the addition of aminoguanidine (AG), a selective inhibitor of inducible NOS (iNOS). The relaxation response was also affected by tetraethylammonium, an inhibitor of endothelium-derived hyperpolarizing factor activity. In the second model, we investigated the biochemical events of nitrosative stress in human umbilical-vein endothelial cells (HUVECs). We measured iNOS and nitrotyrosine expression in HUVECs exposed to a dose of 4 Gy. The expression of iNOS and nitrotyrosine was greater in irradiated HUVECs than in untreated controls. Pretreatment with AG, L-N 6 -(1-iminoethyl) lysine hydrochloride (a selective inhibitor of iNOS), and L-NA attenuated nitrosative stress. While a selective target of radiation-induced vascular endothelial damage was not definitely determined, these results suggest that NO generated from iNOS could contribute to vasorelaxation. These studies highlight a potential role of iNOS inhibitors in ameliorating radiation-induced vascular endothelial damage. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-03-15

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

  5. Lovastatin attenuates ionizing radiation-induced normal tissue damage in vivo

    International Nuclear Information System (INIS)

    Ostrau, Christian; Huelsenbeck, Johannes; Herzog, Melanie; Schad, Arno; Torzewski, Michael; Lackner, Karl J.; Fritz, Gerhard

    2009-01-01

    Background and purpose: HMG-CoA-reductase inhibitors (statins) are widely used lipid-lowering drugs. Moreover, they have pleiotropic effects on cellular stress responses, proliferation and apoptosis in vitro. Here, we investigated whether lovastatin attenuates acute and subchronic ionizing radiation-induced normal tissue toxicity in vivo. Materials and methods: Four hours to 24 h after total body irradiation (6 Gy) of Balb/c mice, acute pro-inflammatory and pro-fibrotic responses were analyzed. To comprise subchronic radiation toxicity, mice were irradiated twice with 2.5 Gy and analyses were performed 3 weeks after the first radiation treatment. Molecular markers of inflammation and fibrosis as well as organ toxicities were measured. Results: Lovastatin attenuated IR-induced activation of NF-κB, mRNA expression of cell adhesion molecules and mRNA expression of pro-inflammatory and pro-fibrotic marker genes (i.e. TNFα, IL-6, TGFβ, CTGF, and type I and type III collagen) in a tissue- and time-dependent manner. γH2AX phosphorylation stimulated by IR was not affected by lovastatin, indicating that the statin has no major impact on the induction of DNA damage in vivo. Radiation-induced thrombopenia was significantly alleviated by lovastatin. Conclusions: Lovastatin inhibits both acute and subchronic IR-induced pro-inflammatory and pro-fibrotic responses and cell death in normal tissue in vivo. Therefore, lovastatin might be useful for selectively attenuating acute and subchronic normal tissue damage caused by radiotherapy.

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

    CERN Document Server

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

    2016-01-01

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

  7. Radiation-induced damage of the Wistar Rat heart

    International Nuclear Information System (INIS)

    Cilliers, G.D.; Lochner, A.

    1993-01-01

    A time sequence study was performed on Wistar rats to investigate the early effects of radiation on the mechanical function and energy metabolism of the heart. Two series of rats were exposed to 20 Gy electron irradiation to a field including the heart and approximately a third of the lungs. The hearts were excised at varying time intervals (8-180 days) post irradiation. In one series of hearts the mechanical function was measured using the isolated perfused working rat heart model. At the end of the perfusion the hearts were freeze-clamped for analysis of the high energy phosphate contents (ATP, ADP, AMP and creatine phosphate). In the second series, mitochondria were isolated and the oxidative phosphorylation function measured polarographically (substrate: glutamate). Maximal depression of mechanical function was observed at 60 days post irradiation. Thereafter the work performance of these hearts improved significantly, almost reaching control levels after 180 days. The mitochondrial oxidative phosphorylation function (as measured on the total mitochondrial population) was significantly depressed 30-120 days post irradiation. As in the case of the mechanical changes, the depression was transient and after 180 days post irradiation, values similar to those of controls were obtained. Myocardial high energy phosphates remained unaltered throughout the experiment. (author)

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

    CERN Document Server

    Hoang Dac Luc; Hoang Dac Dat

    2003-01-01

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

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

    International Nuclear Information System (INIS)

    Hoang Dac Luc; Vo Tuong Hanh; Hoang Dac Dat

    2003-01-01

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

  10. Ellagic and ferulic acids alleviate gamma radiation and aluminium chloride-induced oxidative damage.

    Science.gov (United States)

    Salem, Ahmed M; Mohammaden, Tarek F; Ali, Mohamed A M; Mohamed, Enas A; Hasan, Hesham F

    2016-09-01

    Ionizing radiation interacts with biological systems through the generation of free radicals, which induce oxidative stress. Aluminium (Al) can negatively impact human health by direct interaction with antioxidant enzymes. Ellagic acid (EA) and Ferulic acid (FA) are plant polyphenolic compounds, have gained attention due to their multiple biological activities. To date, no studies investigating the antioxidant effect of EA/FA in a model involving both γ radiation and aluminium chloride (AlCl3) have been reported. Herein, we investigated the protective effect of EA and FA against oxidative stress induced by γ radiation and AlCl3 in rats. Rats were divided into thirteen groups: a negative control group, 3 positive control groups (γ-irradiated, AlCl3-treated and γ-irradiated+AlCl3-treated) and 9 groups (3 γ-irradiated, 3 AlCl3-treated and 3 γ-irradiated+AlCl3-treated) treated with EA and/or FA. Liver function and lipid profile were assessed. Levels of lipid peroxidation, protein oxidation and endogenous antioxidants as well as the concentrations of copper, iron and zinc were estimated in liver tissue homogenate. Furthermore, liver tissue sections were histologically examined. Oral administration of EA and/or FA resulted in 1) amelioration of AlCl3 and/or γ-radiation-induced hepatic function impairment, dyslipidemia and hepatic histological alterations; 2) reduction in liver MDA and PCC levels; 3) elevation of liver CAT, GPx and SOD activity as well as GSH level; 4) elevation in liver Cu concentrations which was accompanied by a reduction in Fe and Zn concentrations. Oral administration of EA and/or FA may be useful for ameliorating γ radiation and/or AlCl3-induced oxidative damage. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Cranial Radiation Therapy and Damage to Hippocampal Neurogenesis

    Science.gov (United States)

    Monje, Michelle

    2008-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Frankenfield, Zackery [Department of Physics, West Chester University of PA, West Chester, PA 19382 (United States); Kane, Kenneth [Department of Physics, West Chester University of PA, West Chester, PA 19382 (United States); Current address: Department of Physics, Virginia Commonwealth University, Richmond, VA 23228 (United States); Sawyer, William H., E-mail: wsawyer@wcupa.edu [Department of Physics, West Chester University of PA, West Chester, PA 19382 (United States)

    2017-03-15

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

  13. A generalized linear-quadratic model incorporating reciprocal time pattern of radiation damage repair

    International Nuclear Information System (INIS)

    Huang, Zhibin; Mayr, Nina A.; Lo, Simon S.; Wang, Jian Z.; Jia Guang; Yuh, William T. C.; Johnke, Roberta

    2012-01-01

    Purpose: It has been conventionally assumed that the repair rate for sublethal damage (SLD) remains constant during the entire radiation course. However, increasing evidence from animal studies suggest that this may not the case. Rather, it appears that the repair rate for radiation-induced SLD slows down with increasing time. Such a slowdown in repair would suggest that the exponential repair pattern would not necessarily accurately predict repair process. As a result, the purpose of this study was to investigate a new generalized linear-quadratic (LQ) model incorporating a repair pattern with reciprocal time. The new formulas were tested with published experimental data. Methods: The LQ model has been widely used in radiation therapy, and the parameter G in the surviving fraction represents the repair process of sublethal damage with T r as the repair half-time. When a reciprocal pattern of repair process was adopted, a closed form of G was derived analytically for arbitrary radiation schemes. The published animal data adopted to test the reciprocal formulas. Results: A generalized LQ model to describe the repair process in a reciprocal pattern was obtained. Subsequently, formulas for special cases were derived from this general form. The reciprocal model showed a better fit to the animal data than the exponential model, particularly for the ED50 data (reduced χ 2 min of 2.0 vs 4.3, p = 0.11 vs 0.006), with the following gLQ parameters: α/β = 2.6-4.8 Gy, T r = 3.2-3.9 h for rat feet skin, and α/β = 0.9 Gy, T r = 1.1 h for rat spinal cord. Conclusions: These results of repair process following a reciprocal time suggest that the generalized LQ model incorporating the reciprocal time of sublethal damage repair shows a better fit than the exponential repair model. These formulas can be used to analyze the experimental and clinical data, where a slowing-down repair process appears during the course of radiation therapy.

  14. A generalized linear-quadratic model incorporating reciprocal time pattern of radiation damage repair.

    Science.gov (United States)

    Huang, Zhibin; Mayr, Nina A; Lo, Simon S; Wang, Jian Z; Jia, Guang; Yuh, William T C; Johnke, Roberta

    2012-01-01

    It has been conventionally assumed that the repair rate for sublethal damage (SLD) remains constant during the entire radiation course. However, increasing evidence from animal studies suggest that this may not the case. Rather, it appears that the repair rate for radiation-induced SLD slows down with increasing time. Such a slowdown in repair would suggest that the exponential repair pattern would not necessarily accurately predict repair process. As a result, the purpose of this study was to investigate a new generalized linear-quadratic (LQ) model incorporating a repair pattern with reciprocal time. The new formulas were tested with published experimental data. The LQ model has been widely used in radiation therapy, and the parameter G in the surviving fraction represents the repair process of sublethal damage with T(r) as the repair half-time. When a reciprocal pattern of repair process was adopted, a closed form of G was derived analytically for arbitrary radiation schemes. The published animal data adopted to test the reciprocal formulas. A generalized LQ model to describe the repair process in a reciprocal pattern was obtained. Subsequently, formulas for special cases were derived from this general form. The reciprocal model showed a better fit to the animal data than the exponential model, particularly for the ED50 data (reduced χ(2) (min) of 2.0 vs 4.3, p = 0.11 vs 0.006), with the following gLQ parameters: α/β = 2.6-4.8 Gy, T(r) = 3.2-3.9 h for rat feet skin, and α/β = 0.9 Gy, T(r) = 1.1 h for rat spinal cord. These results of repair process following a reciprocal time suggest that the generalized LQ model incorporating the reciprocal time of sublethal damage repair shows a better fit than the exponential repair model. These formulas can be used to analyze the experimental and clinical data, where a slowing-down repair process appears during the course of radiation therapy.

  15. Solar radiation induced skin damage: review of protective and preventive options.

    Science.gov (United States)

    Svobodová, Alena; Vostálová, Jitka

    2010-12-01

    Solar energy has a number of short- and long-term detrimental effects on skin that can result in several skin disorders. The aim of this review is to summarise current knowledge on endogenous systems within the skin for protection from solar radiation and present research findings to date, on the exogenous options for such skin photoprotection. Endogenous systems for protection from solar radiation include melanin synthesis, epidermal thickening and an antioxidant network. Existing lesions are eliminated via repair mechanisms. Cells with irreparable damage undergo apoptosis. Excessive and chronic sun exposure however can overwhelm these mechanisms leading to photoaging and the development of cutaneous malignancies. Therefore exogenous means are a necessity. Exogenous protection includes sun avoidance, use of photoprotective clothing and sufficient application of broad-spectrum sunscreens as presently the best way to protect the skin. However other strategies that may enhance currently used means of protection are being investigated. These are often based on the endogenous protective response to solar light such as compounds that stimulate pigmentation, antioxidant enzymes, DNA repair enzymes, non-enzymatic antioxidants. More research is needed to confirm the effectiveness of new alternatives to photoprotection such as use of DNA repair and antioxidant enzymes and plant polyphenols and to find an efficient way for their delivery to the skin. New approaches to the prevention of skin damage are important especially for specific groups of people such as (young) children, photosensitive people and patients on immunosuppressive therapy. Changes in public awareness on the subject too must be made.

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

    Directory of Open Access Journals (Sweden)

    Srećković Milesa Ž.

    2015-01-01

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

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

    International Nuclear Information System (INIS)

    1999-01-01

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

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

    CERN Document Server

    Beynel, P; Schönbacher, H; CERN. Geneva

    1982-01-01

    For pt.II see CERN report 79-08 (1979). This handbook gives the results of radiation damage tests on various engineering materials and components intended for installation in radiation areas of the CERN high-energy particle accelerators. It complements two previous volumes covering organic cable-insulating materials and thermoplastic and thermosetting resins.

  19. From electrons to stars : modelling and mitigation of radiation damage effects on astronomical CCDs

    NARCIS (Netherlands)

    Prod'homme, Thibaut

    2011-01-01

    The work presented in this thesis is part of an on-going effort to understand and mitigate the effects of radiation damage in astronomical CCDs. My research was motivated by and took place in the challenging context of the European Space Agency’s (ESA) astrometric mission, Gaia, for which radiation

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-06-01

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

  1. Protective effect of zingerone, a dietary compound against radiation induced damage

    International Nuclear Information System (INIS)

    Satish Rao, B.S.; Rao, Nageshwar

    2012-01-01

    The radioprotective potential of phenolic alkanone, Zingerone (ZO) was investigated using human peripheral blood lymphocytes as well as Chinese hamster fibroblast (V79) cells growing in vitro and in vivo by using Swiss albino mice exposed to gamma radiation. In the in vivo studies, mice were administered with ZO (10-100 mg/kg b.wt), once daily for five consecutive days. One hour after the last administration of ZO on the fifth day, animals were whole body exposed to 10 Gy gamma radiations. The radioprotective potential was assessed using animal survival, haemopoietic stem cell survival (CFU) assay, mouse bone marrow micronucleus test, histological observations of intestinal and bone marrow damage. Effect of ZO pretreatment on radiation-induced changes in glutathione (GSH), glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT) and lipid peroxidation (LPx) levels was also analyzed. ZO treatment resulted increase in the LD50/30 by 1.8 Gy (dose reduction factor = 1.2). The number of spleen colonies after whole body irradiation of mice (4.5 or 7.5 Gy) was increased when ZO was administered 1 h prior to irradiation. The histological observations indicated a decline in the villus height and crypt number with an increase in goblet and dead cell population in the irradiated group, which was normalized by pretreatment with ZO. A significant (p < 0.001) reduction in micronucleated polychromatic, normochromatic erythrocytes, increased PCE/NCE ratio, increase in the GSH, GST, SOD, CAT and decreased LPx levels were observed in ZO by pretreated group when compared to the irradiated animals. Our in vitro and in vivo studies demonstrate the potential of ZO in mitigating radiation-induced cytotoxic, genotoxicity, apoptosis in cell culture and animal mortality, cytogenetic damage, intestinal and bone marrow protection in vivo. Radioprotective potential of ZO may be attributed to the inhibition radiation-induced decline in the endogenous antioxidant levels

  2. Concrete alkali-silica reaction and nuclear radiation damage

    International Nuclear Information System (INIS)

    Ichikawa, Tsuneki

    2008-01-01

    The deterioration of concrete by alkali-silica reaction of aggregates (ASR) and the effect of nuclear radiations on the ASR have been reviewed based on our studies on the mechanism of ASR and the effect of nuclear radiations on the resistivity of minerals to alkaline solution. It has been found that the ASR is initiated by the attack of alkaline solution in concrete to silicious aggregates to convert them into hydrated alkali silicate. The consumption of alkali hydroxide by the aggregates induces the dissolution of Ca 2+ ions into the solution. The alkali silicate surrounding the aggregates then reacts with Ca 2+ ions to convert to insoluble tight and rigid reaction rims. The reaction rim allows the penetration of alkaline solution but prevents the leakage of viscous alkali silicate, so that alkali silicate generated afterward is accumulated in the aggregate to give an expansive pressure enough for cracking the aggregate and the surrounding concrete. The effect of nuclear radiation on the reactivity of quartz and plagioclase, a part of major minerals composing volcanic rocks as popular aggregates, to alkaline solution has been examined for clarifying whether nuclear radiations accelerates the ASR. It has been found that the irradiation of these minerals converts them into alkali-reactive amorphous ones. The radiation dose for plagioclase is as low as 10 8 Gy, which suggests that the ASR of concrete surrounding nuclear reactors is possible to be accelerated by nuclear radiation. (author)

  3. Jagiellonian University Radiation Damage in Silicon Particle Detectors in High Luminosity Experiments

    CERN Document Server

    Oblakowska-Mucha, A

    2017-01-01

    Radiation damage is nowadays the most serious problem in silicon particle detectors placed in the very harsh radiation environment. This problem will be even more pronounced after the LHC Upgrade because of extremely strong particle fluences never encountered before. In this review, a few aspects of radiation damage in silicon trackers are presented. Among them, the change in the silicon lattice and its influence on the detector performance are discussed. Currently applied solutions and the new ideas for future experiments will be also shown. Most of the results presented in this summary were obtained within the RD50 Collaboration

  4. Complex DNA Damage: A Route to Radiation-Induced Genomic Instability and Carcinogenesis

    Directory of Open Access Journals (Sweden)

    Ifigeneia V. Mavragani

    2017-07-01

    Full Text Available Cellular effects of ionizing radiation (IR are of great variety and level, but they are mainly damaging since radiation can perturb all important components of the cell, from the membrane to the nucleus, due to alteration of different biological molecules ranging from lipids to proteins or DNA. Regarding DNA damage, which is the main focus of this review, as well as its repair, all current knowledge indicates that IR-induced DNA damage is always more complex than the corresponding endogenous damage resulting from endogenous oxidative stress. Specifically, it is expected that IR will create clusters of damage comprised of a diversity of DNA lesions like double strand breaks (DSBs, single strand breaks (SSBs and base lesions within a short DNA region of up to 15–20 bp. Recent data from our groups and others support two main notions, that these damaged clusters are: (1 repair resistant, increasing genomic instability (GI and malignant transformation and (2 can be considered as persistent “danger” signals promoting chronic inflammation and immune response, causing detrimental effects to the organism (like radiation toxicity. Last but not least, the paradigm shift for the role of radiation-induced systemic effects is also incorporated in this picture of IR-effects and consequences of complex DNA damage induction and its erroneous repair.

  5. [Role of photoreactivation in case of corneal damage from ultraviolet radiation].

    Science.gov (United States)

    Lysak, V F; Krasnovidov, V S; Kidalov, V N; Zelentsov, I V; Marat, O V

    1990-01-01

    Experimentally, the role of photoreactivation in appearance of ultraviolet lesions of corneal epithelium has been studied in white rats. The lesions were induced by ultraviolet radiation, 0.28 mcm wavelength, and intensive (20000 lx) light of a xenon lamp with light filters was used as a reactivating light. The damaging dose as a reactivating light. The damaging dose of ultraviolet radiation by photokeratitis criterion was 11 +/- 2.4 mJ.cm-2. Simultaneous illumination of the animal eye by the damaging ultraviolet light and reactivating radiation exceeded a damaging threshold to 18 +/- 4.0 mJ.cm-2. The results obtained have convincingly shown, that photoreactivation, as a phenomenon, manifested itself in the corneal epithelium and was detected by biomicroscopy of the eye with epithelium staining by a 1% fluorescein solution.

  6. Radiation damage studies on the optical and mechanical properties of plastic scintillators

    International Nuclear Information System (INIS)

    Mizue Hamada, Margarida; Roberto Rela, Paulo; Eduardo da Costa, Fabio; Henrique de Mesquita, Carlos

    1999-01-01

    This paper describes the radiation damage studies on a large volume plastic scintillator based in polystyrene doped with PPO and POPOP. The consequences on their mechanical and scintillation properties were evaluated before and after irradiation with different dose rates of 60 Co gamma radiation, in several doses. The optical results show a significant difference in the radiation susceptibility, when the plastic scintillator is irradiated at low rate (0.1 kGy/h) with that irradiated at high dose rate (85 kGy/h). The losses in the optical and mechanical properties increase as the irradiation dose is increased. The damage evaluated by the transmittance, emission intensity, pulse height and tensile strength was normalized as a damage fraction and fitted by a bi-exponential function. It was observed that the damage for irradiation is not permanent and it obeys a bi-exponential function

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-07-01

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

  8. Characterization of radiation damage induced by swift heavy ions in graphite

    Energy Technology Data Exchange (ETDEWEB)

    Hubert, Christian

    2016-05-15

    Graphite is a classical material in neutron radiation environments, being widely used in nuclear reactors and power plants as a moderator. For high energy particle accelerators, graphite provides ideal material properties because of the low Z of carbon and its corresponding low stopping power, thus when ion projectiles interact with graphite is the energy deposition rather low. This work aims to improve the understanding of how the irradiation with swift heavy ions (SHI) of kinetic energies in the range of MeV to GeV affects the structure of graphite and other carbon-based materials. Special focus of this project is given to beam induced changes of thermo-mechanical properties. For this purpose the Highly oriented pyrolytic graphite (HOPG) and glassy carbon (GC) (both serving as model materials), isotropic high density polycrystalline graphite (PG) and other carbon based materials like carbon fiber carbon composites (CFC), chemically expanded graphite (FG) and molybdenum carbide enhanced graphite composites (MoC) were exposed to different ions ranging from {sup 131}Xe to {sup 238}U provided by the UNILAC accelerator at GSI in Darmstadt, Germany. To investigate structural changes, various in-situ and off-line measurements were performed including Raman spectroscopy, x-ray diffraction and x-ray photo-electron spectroscopy. Thermo-mechanical properties were investigated using the laser-flash-analysis method, differential scanning calorimetry, micro/nano-indentation and 4-point electrical resistivity measurements. Beam induced stresses were investigated using profilometry. Obtained results provided clear evidence that ion beam-induced radiation damage leads to structural changes and degradation of thermal, mechanical and electrical properties of graphite. PG transforms towards a disordered sp2 structure, comparable to GC at high fluences. Irradiation-induced embrittlement is strongly reducing the lifetime of most high-dose exposed accelerator components. For

  9. Radiation Damage Mechanism in PbWO4 Crystal and Radiation Hardness Quality Control of PWO Scintillators for CMS

    CERN Document Server

    Baccaro, Stefania; Borgia, Bruno; Cavallari, Francesca; Cecilia, Angelica; Dafinei, Ioan; Diemoz, Marcella; Lecoq, Paul; Longo, Egidio; Montecchi, Marco; Organtini, Giovanni; Salvatori, S

    1997-01-01

    The optical damage induced by UV light in PbWO4 crystals is found to be similar to that induced by g radiation. Due to the peculiarities of optical absorption in PbWO4, the damage induced by UV light is a bulk process. This fact has important consequences for the approach to be adopted both for the use of the crystal as scintillator and for the qualification methods foreseen in the Regional Centres of the ECAL CMS Collaboration.

  10. Radioresistance of GGG sequences to prompt strand break formation from direct-type radiation damage.

    Science.gov (United States)

    Black, Paul J; Miller, Adam S; Hayes, Jeffrey J

    2016-11-01

    As humans, we are constantly exposed to ionizing radiation from natural, man-made and cosmic sources which can damage DNA, leading to deleterious effects including cancer incidence. In this work, we introduce a method to monitor strand breaks resulting from damage due to the direct effect of ionizing radiation and provide evidence for sequence-dependent effects leading to strand breaks. To analyze only DNA strand breaks caused by radiation damage due to the direct effect of ionizing radiation, we combined an established technique to generate dehydrated DNA samples with a technique to analyze single-strand breaks on short oligonucleotide sequences via denaturing gel electrophoresis. We find that direct damage primarily results in a reduced number of strand breaks in guanine triplet regions (GGG) when compared to isolated guanine (G) bases with identical flanking base context. In addition, we observe strand break behavior possibly indicative of protection of guanine bases when flanked by pyrimidines and sensitization of guanine to strand break when flanked by adenine (A) bases in both isolated G and GGG cases. These observations provide insight into the strand break behavior in GGG regions damaged via the direct effect of ionizing radiation. In addition, this could be indicative of DNA sequences that are naturally more susceptible to strand break due to the direct effect of ionizing radiation.

  11. DNA Damage by Ionizing Radiation: Tandem Double Lesions by Charged Particles

    Science.gov (United States)

    Huo, Winifred M.; Chaban, Galina M.; Wang, Dunyou; Dateo, Christopher E.

    2005-01-01

    Oxidative damages by ionizing radiation are the source of radiation-induced carcinogenesis, damage to the central nervous system, lowering of the immune response, as well as other radiation-induced damages to human health. Monte Carlo track simulations and kinetic modeling of radiation damages to the DNA employ available molecular and cellular data to simulate the biological effect of high and low LET radiation io the DNA. While the simulations predict single and double strand breaks and base damages, so far all complex lesions are the result of stochastic coincidence from independent processes. Tandem double lesions have not yet been taken into account. Unlike the standard double lesions that are produced by two separate attacks by charged particles or radicals, tandem double lesions are produced by one single attack. The standard double lesions dominate at the high dosage regime. On the other hand, tandem double lesions do not depend on stochastic coincidences and become important at the low dosage regime of particular interest to NASA. Tandem double lesions by hydroxyl radical attack of guanine in isolated DNA have been reported at a dosage of radiation as low as 10 Gy. The formation of two tandem base lesions was found to be linear with the applied doses, a characteristic of tandem lesions. However, tandem double lesions from attack by a charged particle have not been reported.

  12. THEORETICAL INVESTIGATION OF MICROSTRUCTURE EVOLUTION AND DEFORMATION OF ZIRCONIUM UNDER CASCADE DAMAGE CONDITIONS

    Energy Technology Data Exchange (ETDEWEB)

    Barashev, Alexander V [ORNL; Golubov, Stanislav I [ORNL; Stoller, Roger E [ORNL

    2012-06-01

    This work is based on our reaction-diffusion model of radiation growth of Zr-based materials proposed recently in [1]. In [1], the equations for the strain rates in unloaded pure crystal under cascade damage conditions of, e.g., neutron or heavy-ion irradiation were derived as functions of dislocation densities, which include contributions from dislocation loops, and spatial distribution of their Burgers vectors. The model takes into account the intra-cascade clustering of self-interstitial atoms and their one-dimensional diffusion; explains the growth stages, including the break-away growth of pre-annealed samples; and accounts for some striking observations, such as of negative strain in prismatic direction, and co-existence of vacancy- and interstitial-type prismatic loops. In this report, the change of dislocation densities due to accumulation of sessile dislocation loops is taken into account explicitly to investigate the dose dependence of radiation growth. The dose dependence of climb rates of dislocations is calculated, which is important for the climb-induced glide model of radiation creep. The results of fitting the model to available experimental data and some numerical calculations of the strain behavior of Zr for different initial dislocation structures are presented and discussed. The computer code RIMD-ZR.V1 (Radiation Induced Microstructure and Deformation of Zr) developed is described and attached to this report.

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

    CERN Document Server

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

    2014-01-01

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

  14. Efficacy of wheat germ oil in modulating radiation-induced heart damage in rats

    International Nuclear Information System (INIS)

    Said, U.Z.; Azab, Kh.Sh.

    2006-01-01

    Wheat Germ oil is a natural unrefined vegetable oil. It is an excellent source of vitamin E, octacosanol, linoleic and linolenic essential fatty acids, which may be beneficial in neutralizing the free oxygen radicals. This study was designed to investigate the cardio-protective efficacy of wheat germ oil, on radiation-induced oxidative damage in rat's heart. Wheat germ oil was supplemented by gavage to rats at a dose of 81 mg/ kg body wt for 10 successive days pre- and 7 successive days post-exposure to 7 Gy (single dose) of whole body gamma irradiation. The dose of wheat germ oil is equivalent to daily human nutritional supplementation quantity. The results revealed that whole body ?-irradiation of rats produced significant alterations in blood cells picture. The erythrocyte, leucocyte, platelet counts and hemoglobin levels decreased after irradiation. Also, radiation-induced biochemical disorders manifested by significant elevation in xanthine oxidase activity (XO) and thiobarbituric acid reactive substances (TBARS) level, with decrease in reduced glutathione (GSH) content in heart tissues, indicating depression in the antioxidant status. Serum lipid profile as total cholesterol, high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C) and triglycerides levels (TG) were significantly higher than normal control rats. Radiation exposure produced a significant rise in the activities of serum markers for heart damage as creatine phosphokinase (CPK), aspartate aminotransferase (AST) and lactic dehydrogenase (LDH) indicating acute cardiac toxicity. Moreover, the obtained results revealed abnormal electrophoretic pattern of LDH isoenzymes in the 7th day after exposure to gamma rays. Three bands only appear on the agarose film comparing with 4 bands in normal control rats. The rats that received wheat germ oil supplement showed significantly less severe damage and remarkable improvement in all of the measured parameters when compared to

  15. Resveratrol attenuates radiation damage in Caenorhabditis elegans by preventing oxidative stress

    International Nuclear Information System (INIS)

    Ye Kan; Gu Guixiong; Ji Chenbo; Ni Yuhui; Chen Xiaohui; Guo Xirong; Lu Xiaowei; Gao Chunlin; Zhao Yaping

    2010-01-01

    Resveratrol, a member of a class of polyphenolic compounds known as flavonols, has been extensively studied for its anticancer, antiviral, anti-inflammatory, and neuroprotective roles. Caenorhabidits elegans is a well-established animal for investigating responses to radiation. We found that resveratrol may provide protection against hazardous radiation. Pre-treatment with resveratrol extended both the maximum and mean life span of irradiated C. elegans. Resveratrol acted as a strong radical scavenger and regulated superoxide dismutase (SOD) expression. In addition, resveratrol was shown to be capable of alleviating γ-ray radiation exposure-induced reduction in mitochondrial SOD expression. Ultimately, a correlation may exist between dietary intake of trace amounts of resveratrol and anti-aging effects. A specific response mechanism may be activated after the administration of resveratrol in irradiated animals. Our results suggest the protective effect of resveratrol is due to its strong ability to protect from oxidative stress and protective effects in mitochondria. Therefore, resveratrol is potentially an effective protecting agent against irradiative damage. (author)

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

    International Nuclear Information System (INIS)

    Robles, E.; Balcazar, M.; Alpizar, A.M.; Calderon, B.E.

    2002-01-01

    The structural materials which are manufactured the pressure vessels of the BWR reactors undergo degradation in their mechanical properties mainly due to the damage produced by the fast neutrons (E> 1 MeV) coming from the reactor core. The mechanisms of neutron damage in this type of materials are experimentally studied, through the irradiation of vessel steel in experimental reactors for a quickly ageing. Alternately the neutron damage through steel irradiation with heavy ions is simulated. In this work the first results of the damage induced by irradiation of a similar steel to the vessel of a BWR reactor are shown. The irradiation was performed with fast neutrons (E> 1 MeV, fluence of 1.45 x 10 18 n/cm 2 ) in the TRIGA Mark III Salazar reactor and separately with Ni +3 ions in a Tandetrom accelerator (E= 4.8 MeV and an ion flux rank of 0.1 to 53 ions/A 2 ). (Author)

  17. 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

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

    International Nuclear Information System (INIS)

    El-Tahawy, N.A; Said, U.Z

    2010-01-01

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

  19. Immune status investigations for radiation workers

    International Nuclear Information System (INIS)

    Obreja, D.; Tulbure, R.; Marinescu, I.

    2002-01-01

    In Romania, the enhanced development of nuclear energy leads to an increase of number of occupational exposed persons to ionizing radiation. Hence, a good knowledge of effects of ionizing radiation exposure on human body is necessary. Beginning with this decade, the opinion regarding medical surveillance of occupational exposed persons to ionizing radiation has changed - the surveillance system has to insure firstly the prevention of professional diseases. It is important to select some biological tests as helpful indicators both in immediate assessment and in health status prognosis for occupational exposed people in the future. The fact that ionizing radiation leads to immune system modifications is well known. In the last 20 years, the effect of ionizing radiation upon immune system was extensively studied, as a result of an intense research activity and of an improvement of knowledge in the field of immunology. Researches have made important steps in understanding the mechanisms of action and control for immune responses

  20. Investigation and evaluation of electron radiation damage on TiC and TiN protective coatings of Molybdenum for highly stressed first-wall components of fusion machines

    International Nuclear Information System (INIS)

    Wallura, E.; Hoven, H.; Koizlik, K.; Kny, E.

    1995-01-01

    The components of the plasma chamber of fusion reactors are subjected to the plasma wall interaction, a complex system of mechanical, thermal, and irradiation loadings. To investigate special modes of individual load processes (thermal shock, thermal fatigue, erosion) specific laboratory tests in an electron beam welding machine have been carried out. The materials Mo, Mo coated with TiC and with TiN, and bulk sintered TiC and TiN were examined in the tests. The 'post mortem' characterization of the material samples was done by secondary electron microscopy and metallography. One important aim was to determine critical loads as defined by the applied beam power density and the effective beam pulse duration, and to deduce from this load limit curves as a type of quantification of acceptable plasma wall interaction intensity. Below these load limits, Mo showed no induced material defects - neither in the uncoated nor in the coated quality. Above the critical heat load (100 MWm -2 ) severe melting occured in the surface of the uncoated as well as in the coated version - the TiC- and the TiN-coatings were completely eroded or vaporized in the molten crater. An influence of the coatings on the recrystallization of the Mo-melt was not detectable. Outside the molten area the coatings showed honeycombed cracking by thermal shock. In the case of bulk sintered TiC and TiN, marked thermal shock cracking appeared already after loadings with 10 MWm -2 and pulse duration of 0.1 sec. (author)

  1. Taurine Protects Mouse Spermatocytes from Ionizing Radiation-Induced Damage Through Activation of Nrf2/HO-1 Signaling

    Directory of Open Access Journals (Sweden)

    Wenjun Yang

    2017-12-01

    Full Text Available Background/Aims: The increasing prevalence of ionizing radiation exposure has inevitably raised public concern over the potential detrimental effects of ionizing radiation on male reproductive system function. The detection of drug candidates to prevent reproductive system from damage caused by ionizing radiation is urgent. We aimed to investigate the protective role of taurine on the injury of mouse spermatocyte-derived cells (GC-2 subjected to ionizing radiation. Methods: mouse spermatocytes (GC-2 cells were exposed to ionizing radiation with or without treatment of Taurine. The effect of ionizing radiation and Taurine treatment on GC-2 cells were evaluated by cell viability assay (CCK8, cell cycle and apoptosis. The relative protein abundance change was determined by Western blotting. The siRNA was used to explore whether Nrf2 signaling was involved in the cytoprotection of Taurine. Results: Taurine significantly inhibited the decrease of cell viability, percentage of apoptotic cells and cell cycle arrest induced by ionizing radiation. Western blot analysis showed that taurine significantly limited the ionizing radiation-induced down-regulation of CyclinB1 and CDK1, and suppressed activation of Fas/FasL system pathway. In addition, taurine treatment significantly increased the expression of Nrf2 and HO-1 in GC-2 cells exposed to ionizing radiation, two components in antioxidant pathway. The above cytoprotection of Taurine was blocked by siNrf2. Conclusion: Our results demonstrate that taurine has the potential to effectively protect GC-2 cells from ionizing radiation- triggered damage via upregulation of Nrf2/HO-1 signaling.

  2. Taurine Protects Mouse Spermatocytes from Ionizing Radiation-Induced Damage Through Activation of Nrf2/HO-1 Signaling.

    Science.gov (United States)

    Yang, Wenjun; Huang, Jinfeng; Xiao, Bang; Liu, Yan; Zhu, Yiqing; Wang, Fang; Sun, Shuhan

    2017-01-01

    The increasing prevalence of ionizing radiation exposure has inevitably raised public concern over the potential detrimental effects of ionizing radiation on male reproductive system function. The detection of drug candidates to prevent reproductive system from damage caused by ionizing radiation is urgent. We aimed to investigate the protective role of taurine on the injury of mouse spermatocyte-derived cells (GC-2) subjected to ionizing radiation. mouse spermatocytes (GC-2 cells) were exposed to ionizing radiation with or without treatment of Taurine. The effect of ionizing radiation and Taurine treatment on GC-2 cells were evaluated by cell viability assay (CCK8), cell cycle and apoptosis. The relative protein abundance change was determined by Western blotting. The siRNA was used to explore whether Nrf2 signaling was involved in the cytoprotection of Taurine. Taurine significantly inhibited the decrease of cell viability, percentage of apoptotic cells and cell cycle arrest induced by ionizing radiation. Western blot analysis showed that taurine significantly limited the ionizing radiation-induced down-regulation of CyclinB1 and CDK1, and suppressed activation of Fas/FasL system pathway. In addition, taurine treatment significantly increased the expression of Nrf2 and HO-1 in GC-2 cells exposed to ionizing radiation, two components in antioxidant pathway. The above cytoprotection of Taurine was blocked by siNrf2. Our results demonstrate that taurine has the potential to effectively protect GC-2 cells from ionizing radiation- triggered damage via upregulation of Nrf2/HO-1 signaling. © 2017 The Author(s). Published by S. Karger AG, Basel.

  3. Radiation Damage and Long-Term Aging in Gas Detectors

    CERN Document Server

    Titov, Maxim

    2004-01-01

    Aging phenomena constitute one of the most complex and serious potential problems which could limit, or severely impair, the use of gaseous detectors in unprecedented harsh radiation environments. Long-term operation in high-intensity experiments of the LHC-era not only demands extraordinary radiation hardness of construction materials and gas mixtures but also very specific and appropriate assembly procedures and quality checks during detector construction and testing. Recent experimental data from hadron beams is discussed. It is shown that the initial stage of radiation tests, usually performed under isolated laboratory conditions, may not offer the full information needed to extrapolate to the long-term performance of real and full-size detectors at high energy physics facilities. Major factors, closely related to the capability of operating at large localized ionization densities, and which could lead to operation instabilities and subsequent aging phenomena in gaseous detectors, are summarized. Finally,...

  4. [Pulse-modulated Electromagnetic Radiation of Extremely High Frequencies Protects Cellular DNA against Damaging Effect of Physico-Chemical Factors in vitro].

    Science.gov (United States)

    Gapeyev, A B; Lukyanova, N A

    2015-01-01

    Using a comet assay technique, we investigated protective effects of. extremely high frequency electromagnetic radiation in combination with the damaging effect of X-ray irradiation, the effect of damaging agents hydrogen peroxide and methyl methanesulfonate on DNA in mouse whole blood leukocytes. It was shown that the preliminary exposure of the cells to low intensity pulse-modulated electromagnetic radiation (42.2 GHz, 0.1 mW/cm2, 20-min exposure, modulation frequencies of 1 and 16 Hz) caused protective effects decreasing the DNA damage by 20-45%. The efficacy of pulse-modulated electromagnetic radiation depended on the type of genotoxic agent and increased in a row methyl methanesulfonate--X-rays--hydrogen peroxide. Continuous electromagnetic radiation was ineffective. The mechanisms of protective effects may be connected with an induction of the adaptive response by nanomolar concentrations of reactive oxygen species formed by pulse-modulated electromagnetic radiation.

  5. 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.

  6. Fluorescence studies on radiation oxidative damage to membranes ...

    Indian Academy of Sciences (India)

    Unknown

    plasma membrane permeability of thymocytes were monitored by fluorescein diacetate (FDA) and induced intracellular ... polarization has been shown to monitor radiation-induced structural and organizational changes in cell membrane9,11,12 ... fluorescence due to self-quenching. However, after irradiation, leakage of CF ...

  7. Radiation damage to DNA in DNA-protein complexes

    Czech Academy of Sciences Publication Activity Database

    Spotheim Maurizot, M.; Davídková, Marie

    2011-01-01

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

  8. 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...

  9. The Eleventh International Ural Seminar Radiation damage physics of metals and alloys. Abstracts

    International Nuclear Information System (INIS)

    2015-01-01

    The book includes abstracts of the Eleventh International Ural Seminar Radiation damage physics of metals and alloys (Kyshtym, 23 February - 1 March, 2015). General issues of radiation damage physics of metals and alloys are discussed. Materials for nuclear and thermonuclear power engineering, new approaches to the development of radiation-resistant structural steels are in the view of participants. The new trends in the physics of strongly correlated d- and f-electron systems, radiation technologies for creating materials with desired properties are considered. Much attention is paid to the impact of external influences on the structural and phase changes in the actinides, areas related with the study of radiation effects in dielectrics and semiconductors, the development of new devices and techniques for carrying out experiments. During the seminar the traditional School of the young speaker is held [ru

  10. Mechanisms of Retinal Damage from Chronic Laser Radiation.

    Science.gov (United States)

    1981-07-01

    Some terms were peculiar to specific retinal cell types or even to specific intensity levels of exposure. These realizations led to the formulation of a...may be endangered if both phototherapy and supplemental oxygen is administered. In discussing the type and location of histological damage seen in the...monkey retina, one must address what is primary and what is secon- dary. Work with functional measures had led us to evaluate the histologi- cal

  11. Advanced nuclear data for radiation-damage calculations

    International Nuclear Information System (INIS)

    MacFarlane, R.E.; Foster, D.G. Jr.

    1983-01-01

    Accurate calculations of atomic displacement damage in materials exposed to neutrons require detailed spectra for primary recoil nuclei. Such data are not available from direct experimental measurements. Moreover, they cannot always be computed accurately starting from evaluated nuclear data libraries such as ENDF/B-V that were developed primarily for neutron transport applications, because these libraries lack detailed energy-and-angle distributions for outgoing charged particles. Fortunately, a new generation of nuclear model codes is now available that can be used to fill in the missing spectra. One example is the preequilibrium statistical-model code GNASH. For heating and damage applications, a supplementary code called RECOIL has been developed. RECOIL uses detailed reaction data from GNASH, together with angular distributions based on Kalbach-Mann systematics to compute the energy and angle distributions of recoil nuclei. The energy-angle distributions for recoil nuclei and outgoing particles are written out in the new ENDF/B File 6 format. The result is a complete set of nuclear data that can be used to calculate displacement-energy production, heat production, gas production, transmutation, and activation. Sample results for iron are given and compared to the results of conventional damage models such as those used in NJOY

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

    International Nuclear Information System (INIS)

    Sevilla, M.D.

    1996-08-01

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

  13. Processing of radiation-induced clustered DNA damage generates DSB in mammalian cells

    International Nuclear Information System (INIS)

    Gulston, M.K.; De Lara, C.M.; Davis, E.L.; Jenner, T.J.; O'Neill, P.

    2003-01-01

    Full text: Clustered DNA damage sites, in which two or more lesions are formed within a few helical turns of the DNA after passage of a single radiation track, are signatures of DNA modifications induced by ionizing radiation in mammalian cell. With 60 Co-radiation, the abundance of clustered DNA damage induced in CHO cells is ∼4x that of prompt double strand breaks (DSB) determined by PFGE. Less is known about the processing of non-DSB clustered DNA damage induced in cells. To optimize observation of any additional DSB formed during processing of DNA damage at 37 deg C, xrs-5 cells deficient in non-homologous end joining were used. Surprisingly, ∼30% of the DSB induced by irradiation at 37 deg C are rejoined within 4 minutes in both mutant and wild type cells. No significant mis-repair of these apparent DSB was observed. It is suggested that a class of non-DSB clustered DNA damage is formed which repair correctly within 4 min but, if 'trapped' prior to repair, are converted into DSB during the lysis procedure of PFGE. However at longer times, a proportion of non-DSB clustered DNA damage sites induced by γ-radiation are converted into DSB within ∼30 min following post-irradiation incubation at 37 deg C. The corresponding formation of additional DSB was not apparent in wild type CHO cells. From these observations, it is estimated that only ∼10% of the total yield of non DSB clustered DNA damage sites are converted into DSB through cellular processing. The biological consequences that the majority of non-DSB clustered DNA damage sites are not converted into DSBs may be significant even at low doses, since a finite chance exists of these clusters being formed in a cell by a single radiation track

  14. Investigation of Stability Alarming for Retaining Wall Structures with Damage

    Directory of Open Access Journals (Sweden)

    Qian Xu

    2017-01-01

    Full Text Available To warn of the stability of retaining wall structures with damage, a simplified mechanical model and a finite element model of this retaining wall-soil coupling system are established. Via finite element model updating, a baseline finite element model of the wall-soil system is acquired. A damage alarming index ERSD (Energy Ratio Standard Deviation is proposed via the wavelet packet analysis of a virtual impulse response function of dynamic responses to this baseline finite element model. The internal relationships among the alarming index, earth pressure, and damage stability of the wall are analyzed. Then, a damage stability alarming method for the retaining walls is advanced. To verify the feasibility and validity of this alarming method, vibration tests on the baseline finite element model of a pile plate retaining wall are performed. The ERSD is used as an alarm for the damage stability of the wall. Analysis results show that, with an increase in the ERSD, the stability of the wall changes from a stable state to an unstable one. The wall reaches a critical stable state when the alarming index reaches its threshold value. Thus, the damage stability of this pile plate retaining wall can be alarmed via ERSD.

  15. Characterization of ionizing radiation damage in DNA. Progress report, May 1, 1974--April 30, 1975

    International Nuclear Information System (INIS)

    Hawkins, R.B.

    1975-01-01

    The objective of this research is the characterization and quantitative assay of ionizing radiation induced damage in DNA and nucleoprotein. Two lines of investigation have been pursued. The first is aimed at detection and assay of the amount of DNA to protein covalent cross linkage in coliphage T7. Protein and DNA are labeled with 14 C and 32 P, respectively. Cross linkage is assessed from the amount of labeled protein remaining with DNA after efforts to separate the two components by countercurrent distribution in a phenol-water system. It has been found that cross linkage occurs in phage irradiated with cobalt 60 gamma radiation while in dilute neutral aqueous solutions of phosphate buffer and phosphate buffer plus 1-histidine. Cross linkage is largely due to indirect effects and accompanied by protein and DNA fragmentation. The second line of investigation is a study of the hydrodynamic and viscoelastic properties of dilute solution of DNA from irradiated bacteriophage and cells. A device for this purpose, which will measure the elastic retardation time of DNA solutions, is being constructed. (U.S.)

  16. Novel Experimental Techniques to Investigate Wellbore Damage Mechanisms

    Science.gov (United States)

    Choens, R. C., II; Ingraham, M. D.; Lee, M.; Dewers, T. A.

    2017-12-01

    A new experimental technique with unique geometry is presented investigating deformation of simulated boreholes using standard axisymmetric triaxial deformation equipment. The Sandia WEllbore SImulation, SWESI, geometry, uses right cylinders of rock 50mm in diameter and 75mm in length. A 11.3mm hole is drilled perpendicular to the axis of the cylinder in the center of the sample to simulate a borehole. The hole is covered with a solid metal cover, and sealed with polyurethane. The metal cover can be machined with a high-pressure port to introduce different fluid chemistries into the borehole at controlled pressures. Samples are deformed in a standard load frame under confinement, allowing for a broad range of possible stresses, load paths, and temperatures. Experiments in this study are loaded to the desired confining pressure, then deformed at a constant axial strain rate or 10-5 sec-1. Two different suites of experiments are conducted in this study on sedimentary and crystalline rock types. The first series of experiments are conducted on Mancos Shale, a finely laminated transversely isotropic rock. Samples are cored at three different orientations to the laminations. A second series of experiments is conducted on Sierra White granite with different fluid chemistries inside the borehole. Numerical modelling and experimental observations including CT-microtomography demonstrate that stresses are concentrated around the simulated wellbore and recreate wellbore deformation mechanisms. Borehole strength and damage development is dependent on anisotropy orientation and fluid chemistry. Observed failure geometries, particularly for Mancos shale, can be highly asymmetric. These results demonstrate uncertainties in in situ stresses measurements using commonly-applied borehole breakout techniques in complicated borehole physico-chemical environments. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering

  17. Gamma radiation damage in crotamine (venom of Brazilian rattlesnake)

    International Nuclear Information System (INIS)

    Costa, T.A.; Rogero, J.R.

    1988-01-01

    Ionizing Radiations changes the molecular structure due to chemical bond destruction. These chemical alterations is able to change the biological properties of the macro-molecules. Crotamine was obtained from Crotalus durissus terrificus venom by molecular exclusion cromatography and irradiated in concentration of 2 mg/ml of NaCl 0,85% with gamma radiation produced by a 60 Co source. We used doses of 100 Gy, 250 Gy, 500 Gy, 1000 Gy and 2000 Gy (dose rate = 1,19.10 3 Gy/h). We performed the following experiments: presence of free SH groups, proteic concentration,SDS-PAGE and immunodifusion. Preliminary results showed an increase of the number of bands in SDS-PAGE suggesting the appearence of protein aggregates that proportional to the dose increasing. The immunodiffusion data showed no modification of the immunochemical activity against theButantan anti - sera. (author) [pt

  18. Radiation damage in diagnostic window materials for the TFTR

    Energy Technology Data Exchange (ETDEWEB)

    Primak, W.

    1981-07-01

    The general problem of evaluating diagnostic window materials for the TFTR at the tank wall location is described. Specific evaluations are presented for several materials: vitreous silica, crystal quartz, sapphire, zinc selenide, and several fluorides: lithium fluoride, magnesium fluoride, and calcium fluoride; and seal glasses are discussed. The effects of the neutrons will be minimal. The major problems arise from the high flux of ionizing radiation, mainly the soft x rays which are absorbed near the surface of the materials. Additionally, this large energy deposition causes a significant thermal pulse with attendant thermal stresses. It is thus desirable to protect the windows with cover slips where this is feasible or to reduce the incident radiation by mounting the windows on long pipes. A more detailed summary is given at the end of this report.

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

    Science.gov (United States)

    2010-01-01

    potential for nuclear accidents and accidental exposures will become greater with the expected proliferation of nuclear power plant construction to meet...radiological weapons poses a seri- ous risk of mass casualties. The fact that more than 50% of cancer patients receive radiotherapy at some point during...alone. It is unrealistic however to assume that accidental radiation injury will occur in the absence of other injuries—especially when considering

  20. Radial distribution of radiation damage with heavy ions

    International Nuclear Information System (INIS)

    Francisco, D. H.; Vanni, L.; Saint Martin, Maria L. G.; Kirschbaum, Werner; Bernaola, Omar A.

    1999-01-01

    Foils of 300 μm of an organic material (Makrofol E polycarbonate) were irradiated with 19 F ions of 49.7 MeV and alpha tracers of 360 keV. The irradiated material was processed through successive chemical attacks to evaluate the evolution of the particle diameter. In the case of 19 F, the typical behavior of differential zones in the nm region was observed. However, in the tracers produced by alpha particles the differential zones were still observed, although not very clear. This could suggest that thermal explosion, of low energies effect, is not sufficient to produce a complete 'mixture' of the material in the damaged region. (author)

  1. Immune system investigations for radiation workers

    International Nuclear Information System (INIS)

    Obreja, Doina; Tulbure, Rodica; Marinescu, Irina

    2001-01-01

    During the last decade a great deal of attention has been paid to the research in the field of the immune system. Some important steps forward have been achieved in understanding the mechanisms of action and control of the immunologic responses. At the same time the concern for the possible health effects of exposure to ionizing radiation has considerably increased. On the purpose of the evaluation of the modifications induced by the ionizing radiation for radiation workers, we have applied the method of lymphocytic subpopulations, a method that evinces the proportions for the various subtypes of lymphocytes having different roles within the immune system. A number of 62 persons, employees of the Institute of Physics and Nuclear Engineering at Bucharest - Magurele were involved in this study. All radiation workers from 2 departments characterized by a high exposure to ionizing radiation were included, as follows: Group no. 1, consisting of 20 persons working at RWTS (Radioactive Waste Treating Station), thus presenting both external and internal irradiation; Group no. 2, consisting of 18 persons working at RPC (Radioactive Isotopes Preparing Center), a place where besides the radioactive contamination, the chemical risk was also present. The control group (consisting of 24 persons) was formed of employees from the same institute, with the difference that they were not radiation workers. For the statistical processing of the results the programs EPI INFO 6 and CIA were used. Significantly, when analyzing globally the lymphocytic modifications for TT and/or B lymphocytes (either increments or decrements when compared to the normal values), a noticeable statistical difference among the groups in terms of the frequency of the immune system modifications (Hi square test p=0.001) occurs. The results are in accordance to those in special literature mentioning age as a factor having a role in the appearance of the immune modifications. The obtained results indicate a

  2. Effects of radiation damage in studies of protein-DNA complexes by cryo-EM.

    Science.gov (United States)

    Mishyna, M; Volokh, O; Danilova, Ya; Gerasimova, N; Pechnikova, E; Sokolova, O S

    2017-05-01

    Nucleic acids are responsible for the storage, transfer and realization of genetic information in the cell, which provides correct development and functioning of organisms. DNA interaction with ligands ensures the safety of this information. Over the past 10 years, advances in electron microscopy and image processing allowed to obtain the structures of key DNA-protein complexes with resolution below 4Å. However, radiation damage is a limiting factor to the potentially attainable resolution in cryo-EM. The prospect and limitations of studying protein-DNA complex interactions using cryo-electron microscopy are discussed here. We reviewed the ways to minimize radiation damage in biological specimens and the possibilities of using radiation damage (so-called 'bubblegrams') to obtain additional structural information. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Regrowth zones in laser annealed radiation damaged diamond

    International Nuclear Information System (INIS)

    Jamieson, D.N.; Prawer, S.; Dooley, S.P.; Kalish, R.; Technion-Israel Inst. of Tech., Haifa

    1993-01-01

    Focused laser annealing of ion implanted diamond with a 15 μm diameter laser spot produces as variety of effects that depend on the power density of the laser. Channeling Contrast Microscopy (CCM) provides a relatively straight forward, rapid, method to analyse the annealed regions of the diamond to characterize the effects. In order of increasing laser power density, effects that are observed include: regrowth of the end of range damage of the ion implantation, formation of a buried graphitic layer and complete graphitization of the surface of the diamond down to the bottom of the original damage layer. Information provided by CCM leads to an understanding the causes of these effects and provides insight into the carbon phase diagram in the neighbourhood of the graphite to diamond phase transition. Analysis of the effects of laser annealing by CCM are complicated by the swelling of the diamond lattice caused by the original ion implantation, compaction following regrowth and the effect of the analysis beam irradiation itself. 12 refs., 5 figs

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

    International Nuclear Information System (INIS)

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

    1985-01-01

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

  5. Nonlinear Ultrasonic Techniques to Monitor Radiation Damage in RPV and Internal Components

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, Laurence [Georgia Inst. of Technology, Atlanta, GA (United States); Kim, Jin-Yeon [Georgia Inst. of Technology, Atlanta, GA (United States); Qu, Jisnmin [Northwestern Univ., Evanston, IL (United States); Ramuhalli, Pradeep [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wall, Joe [Electric Power Research Inst. (EPRI), Knoxville, TN (United States)

    2015-11-02

    The objective of this research is to demonstrate that nonlinear ultrasonics (NLU) can be used to directly and quantitatively measure the remaining life in radiation damaged reactor pressure vessel (RPV) and internal components. Specific damage types to be monitored are irradiation embrittlement and irradiation assisted stress corrosion cracking (IASCC). Our vision is to develop a technique that allows operators to assess damage by making a limited number of NLU measurements in strategically selected critical reactor components during regularly scheduled outages. This measured data can then be used to determine the current condition of these key components, from which remaining useful life can be predicted. Methods to unambiguously characterize radiation related damage in reactor internals and RPVs remain elusive. NLU technology has demonstrated great potential to be used as a material sensor – a sensor that can continuously monitor a material’s damage state. The physical effect being monitored by NLU is the generation of higher harmonic frequencies in an initially monochromatic ultrasonic wave. The degree of nonlinearity is quantified with the acoustic nonlinearity parameter, β, which is an absolute, measurable material constant. Recent research has demonstrated that nonlinear ultrasound can be used to characterize material state and changes in microscale characteristics such as internal stress states, precipitate formation and dislocation densities. Radiation damage reduces the fracture toughness of RPV steels and internals, and can leave them susceptible to IASCC, which may in turn limit the lifetimes of some operating reactors. The ability to characterize radiation damage in the RPV and internals will enable nuclear operators to set operation time thresholds for vessels and prescribe and schedule replacement activities for core internals. Such a capability will allow a more clear definition of reactor safety margins. The research consists of three tasks: (1

  6. Crane RF accelerator for high current radiation damage studies

    International Nuclear Information System (INIS)

    Whitham, K.; Anamkath, H.; Evans, K.; Lyons, S.; Palmer, D.; Miller, R.; Treas, P.; Zante, T.

    1992-01-01

    An electron accelerator was designed and built for the Naval Weapons Support Center for transient radiation effects on electronics experiments and testing. The Crane L Band RF Electron Linac was designed to provide high currents over a wide range of pulse widths and energies. The energy extends to 60 MeV and pulse widths vary from a few ns to 10 μsec. Beam currents range from 20 amps in the short pulse case to 1.5 amps in the long pulse case. This paper describes the linac, its architecture, the e-gun and pulser, waveguides, klystrons and modulator, vacuum system, beam transport, and control systems. fig., tab

  7. DNA damage in human lymphocytes due to synergistic interaction between ionizing radiation and pesticide

    International Nuclear Information System (INIS)

    Kim, J. K.; Lee, K. H.; Lee, B. H.; Chun, K. J.

    2001-01-01

    Biological risks may arise from the possibility of the synergistic interaction between harmful factors such as ionizing radiation and pesticide. The effect of pesticide on radiation-induced DNA damage in human in human blood lymphocytes was evaluated by the single cell gel electrophoresis (SCGE) assay. The lymphocytes, with or without pretreatment of the pesticide, were exposed to 2.0 Gy of gamma ray. Significantly increased tail moment, which was a marker of DNA strand breaks in SCGE assay, showed an excellent dose-response relationship. The present study confirms that the pesticide has the cytotoxic effect on lymphocytes and that it interacts synergistically with ionizing radiationon DNA damage, as well

  8. Radiation-Induced Damage and Recovery of Ultra-Nanocrystalline Diamond: Toward Applications in Harsh Environments.

    Science.gov (United States)

    Martin, Aiden A; Filevich, Jorge; Straw, Marcus; Randolph, Steven; Botman, Aurélien; Aharonovich, Igor; Toth, Milos

    2017-11-15

    Ultra-nanocrystalline diamond (UNCD) is increasingly being used in the fabrication of devices and coatings due to its excellent tribological properties, corrosion resistance, and biocompatibility. Here, we study its response to irradiation with kiloelectronvolt electrons as a controlled model for extreme ionizing environments. Real time Raman spectroscopy reveals that the radiation-damage mechanism entails dehydrogenation of UNCD grain boundaries, and we show that the damage can be recovered by annealing at 883 K. Our results have significant practical implications for the implementation of UNCD in extreme environment applications, and indicate that the films can be used as radiation sensors.

  9. Cranial nerve damage in patients after alpha (heavy)-particle radiation to the pituitary

    Energy Technology Data Exchange (ETDEWEB)

    Price, J.; Wei, W.C.; Chong, C.Y.

    1979-06-01

    The records of 161 patients were reviewed to determine if radiation damage had occurred following cranial irradiation. All of these patients had received alpha-particle radiation to their pituitary glands for diabetic retinopathy. Extraocular muscle palsy developed in 11 of these patients, iridoplegia in six, and fifth nerve damage in six. All of the palsies developed within a short period following their irradiation, and a definite dose relationship was present. The estimated doses to the third, fourth, fifth, and sixth cranial nerves was calculated at a saggital plane 13 to 15 mm from the pituitary by using computer-drawn dosimetry charts for the respective aperture size.

  10. Cranial nerve damage in patients after alpha (heavy)-particle radiation to the pituitary

    International Nuclear Information System (INIS)

    Price, J.; Wei, W.C.; Chong, C.Y.

    1979-01-01

    The records of 161 patients were reviewed to determine if radiation damage had occurred following cranial irradiation. All of these patients had received alpha-particle radiation to their pituitary glands for diabetic retinopathy. Extraocular muscle palsy developed in 11 of these patients, iridoplegia in six, and fifth nerve damage in six. All of the palsies developed within a short period following their irradiation, and a definite dose relationship was present. The estimated doses to the third, fourth, fifth, and sixth cranial nerves was calculated at a saggital plane 13 to 15 mm from the pituitary by using computer-drawn dosimetry charts for the respective aperture size

  11. Hyperspectral Imaging as an Early Biomarker for Radiation Exposure and Microcirculatory Damage

    Directory of Open Access Journals (Sweden)

    Michael S. Chin

    2015-10-01

    Full Text Available BACKGROUND: Radiation exposure can lead to detrimental effects in skin microcirculation. The precise relationship between radiation dose received and its effect on cutaneous perfusion still remains controversial. Previously, we have shown that hyperspectral imaging (HSI is able to demonstrate long-term reductions in cutaneous perfusion secondary to chronic microvascular injury. This study characterizes the changes in skin microcirculation in response to varying doses of ionizing radiation and investigates these microcirculatory changes as a possible early non-invasive biomarker that may correlate with the extent of long-term microvascular damage.METHODS: Immunocompetent hairless mice (n=66 were exposed to single fractions of superficial beta-irradiation in doses of 0, 5, 10, 20, 35, or 50 Gy. A HSI device was utilized to measure deoxygenated hemoglobin levels in irradiated and control areas. HSI measurements were performed at baseline before radiation exposure and for the first three days post-irradiation. Maximum macroscopic skin reactions were graded, and histological assessment of cutaneous microvascular densities at four weeks post-irradiation was performed in harvested tissue by CD31 immunohistochemistry.RESULTS: CD31 immunohistochemistry demonstrated a significant correlation (r=0.90, p<0.0001 between dose and vessel density reduction at four weeks. Using HSI analysis, early changes in deoxygenated hemoglobin levels were observed during the first three days post-irradiation in all groups. These deoxygenated hemoglobin changes varied proportionally with dose (r=0.98, p<0.0001 and skin reactions (r=0.98, p<0.0001. There was a highly significant correlation (r= 0.91, p<0.0001 between these early changes in deoxygenated hemoglobin and late vascular injury severity assessed at the end of four weeks.CONCLUSIONS: Radiation dose is directly correlated with cutaneous microvascular injury severity at four weeks in our model. Early post

  12. Relationship between radiation damage on biomembranes and the cell killing

    International Nuclear Information System (INIS)

    Sato, Chikako

    1978-01-01

    Death of unproliferated mammalian erythrocytes causes an increase of ion permeability as membranous damage after x-ray irradiation and hemolysis, and production of peroxides in membrane and an effect of SH base are thought as the causes. As a mechanism of death of small lymphocytes with high radiosensitivity, the following three assumptions were reported: disorder of ATP synthesis in nucleus and cytoplasms, self-digestion by flowing out of proteinase from lysozyme by membranous disorder, and catalysis of DNA-protein complex. Death of proliferated cells causes loss of colony formation ability, and it was explained by colony method using Escherichia coli and mammalian cells and by dose-survival rate. Changes in membranous structure by cellular electrophoretic degree and the relationship between these changes and inhibition of cellular proliferation were mentioned as problems. (Tsunoda, M.)

  13. Seabuckthorn (Hippophae rhamnoides L.) leaf extract ameliorates the gamma radiation mediated DNA damage and hepatic alterations

    International Nuclear Information System (INIS)

    Khan, Amitava; Manna, Krishnendu; Das, Dipesh Kr; Sinha, Mahuya; Kesh, Swaraj Bandhu; Das, Ujjal; Dey, Sanjit; Chinchubose; Banerji, Asoke; Dey, Rakhi Sharma

    2014-01-01

    In vitro assessment showed that H. rhumnoides (HrLE) extract possessed free radical scavenging activities and can protect gamma (γ) radiation induced supercoiled DNA damage. For in vivo study, Swiss albino mice were administered with HrLE (30 mg/kg body weight) for 15 consecutive days before exposing them to a single dose of 5 Gy of γ radiation. HrLE significantly prevented the radiation induced genomic DNA damage indicated as a significant reduction in the comet parameters. The lipid peroxidation, liver function enzymes, expression of phosphorylated NFkB (p65) and IkBα: Ba increased whereas the endogenous antioxidants diminished upon radiation exposure compared to control. Pretreatment of HrLE extract ameliorated these changes. Based on the present results it can be concluded that H. rhamnoides possess a potential preventive element in planned and accidental nuclear exposures. (author)

  14. Cytogenetic methods for the detection of radiation-induced chromosome damage in aquatic organisms

    International Nuclear Information System (INIS)

    Kligerman, A.D.

    1979-01-01

    One means of evaluating the genetic effects of radiation on the genomes of aquatic organisms is to screen radiation-exposed cells for chromosome aberrations. A brief literature review of studies dealing with radiation-induced chromosome damage in aquatic organisms is presented, and reasons are given detailing why most previous studies are of little quantitative value. Suggestions are made for obtaining adequate qualitative and quantitative data through the use of modern cytogenetic methods and a model systems approach to the study of cytogenetic radiation damage in aquatic organisms. Detailed procedures for both in vivo and in vitro cytogenetic methods are described, and experimental considerations are discussed. Finally, suggestions for studies that could be of value in establishing protective guidelines for aquatic ecosystems are presented. (author)

  15. The influence of neutron radiation damage on the optical properties of plastic scintillator UPS 923A

    Science.gov (United States)

    Mthembu, Skhathisomusa; Davydov, Yuri; Baranov, Vladimir; Mellado Garcia, Bruce; Mdhluli, Joyful; Sideras-Haddad, Elias

    2017-09-01

    Plastic scintillators are vital in the reconstruction of hadronic particle energy and tracks resulting from the collision of high energy particles in the Large Hadron Collider (LHC) at CERN. These plastic scintillators are exposed to harsh radiation environments and are susceptible to radiation damage. The effects of radiation damage on the transmittance, luminescence and light yield of Ukraine polystyrene-based scintillator UPS 923A were studied. Samples were irradiated with fast neutrons, of varying energies and fluences, using the IBR-2 reactor FLNP (Frank Laboratory for Nuclear Problems) at the Joint Institute for Nuclear Research. Results show a small change in the transmittance of the higher energy visible spectrum, and a noticeable change in the light yield of the samples as a result of the damage. There is no change observed on the luminescence as a result of radiation damage at studied fluences. The doses and uences of the neutrons shall be increased and changes in optical properties as a result of the radiation shall be further studied.

  16. Evaluation of cytogenetic damage in nuclear medicine personnel occupationally exposed to low-level ionising radiation

    International Nuclear Information System (INIS)

    Garaj-Vrhovac, V.; Kopjar, N.; Poropat, M.

    2005-01-01

    Despite intensive research over the last few decades, there still remains considerable uncertainty as to the genetic impact of ionising radiation on human populations, particularly at low levels. The aim of this study was to provide data on genetic hazards associated with occupational exposure to low doses of ionising radiation in nuclear medicine departments. The assessment of DNA damage in peripheral blood lymphocytes of medical staff was performed using the chromosome aberration (CA) test. Exposed subjects showed significantly higher frequencies of CA than controls. There were significant inter-individual differences in DNA damage within the exposed population, indicating differences in genome sensitivity. Age and gender were not confounding factors, while smoking enhanced the levels of DNA damage only in control subjects. The present study suggests that chronic exposure to low doses of ionising radiation in nuclear medicine departments causes genotoxic damage. Therefore, to avoid potential genotoxic effects, the exposed medical personnel should minimise radiation exposure wherever possible. Our results also point to the significance of biological indicators providing information about the actual risk to the radiation exposed individuals.(author)

  17. Concurrent Transient Activation of Wnt/β-Catenin Pathway Prevents Radiation Damage to Salivary Glands

    International Nuclear Information System (INIS)

    Hai Bo; Yang Zhenhua; Shangguan Lei; Zhao Yanqiu; Boyer, Arthur; Liu, Fei

    2012-01-01

    Purpose: Many head and neck cancer survivors treated with radiotherapy suffer from permanent impairment of their salivary gland function, for which few effective prevention or treatment options are available. This study explored the potential of transient activation of Wnt/β-catenin signaling in preventing radiation damage to salivary glands in a preclinical model. Methods and Materials: Wnt reporter transgenic mice were exposed to 15 Gy single-dose radiation in the head and neck area to evaluate the effects of radiation on Wnt activity in salivary glands. Transient Wnt1 overexpression in basal epithelia was induced in inducible Wnt1 transgenic mice before together with, after, or without local radiation, and then saliva flow rate, histology, apoptosis, proliferation, stem cell activity, and mRNA expression were evaluated. Results: Radiation damage did not significantly affect activity of Wnt/β-catenin pathway as physical damage did. Transient expression of Wnt1 in basal epithelia significantly activated the Wnt/β-catenin pathway in submandibular glands of male mice but not in those of females. Concurrent transient activation of the Wnt pathway prevented chronic salivary gland dysfunction following radiation by suppressing apoptosis and preserving functional salivary stem/progenitor cells. In contrast, Wnt activation 3 days before or after irradiation did not show significant beneficial effects, mainly due to failure to inhibit acute apoptosis after radiation. Excessive Wnt activation before radiation failed to inhibit apoptosis, likely due to extensive induction of mitosis and up-regulation of proapoptosis gene PUMA while that after radiation might miss the critical treatment window. Conclusion: These results suggest that concurrent transient activation of the Wnt/β-catenin pathway could prevent radiation-induced salivary gland dysfunction.

  18. Concurrent Transient Activation of Wnt/{beta}-Catenin Pathway Prevents Radiation Damage to Salivary Glands

    Energy Technology Data Exchange (ETDEWEB)

    Hai Bo; Yang Zhenhua; Shangguan Lei; Zhao Yanqiu [Institute for Regenerative Medicine, Scott and White Hospital, Molecular and Cellular Medicine Department, Texas A and M Health Science Center, Temple, Texas (United States); Boyer, Arthur [Department of Radiology, Scott and White Hospital, Temple, Texas (United States); Liu, Fei, E-mail: fliu@medicine.tamhsc.edu [Institute for Regenerative Medicine, Scott and White Hospital, Molecular and Cellular Medicine Department, Texas A and M Health Science Center, Temple, Texas (United States)

    2012-05-01

    Purpose: Many head and neck cancer survivors treated with radiotherapy suffer from permanent impairment of their salivary gland function, for which few effective prevention or treatment options are available. This study explored the potential of transient activation of Wnt/{beta}-catenin signaling in preventing radiation damage to salivary glands in a preclinical model. Methods and Materials: Wnt reporter transgenic mice were exposed to 15 Gy single-dose radiation in the head and neck area to evaluate the effects of radiation on Wnt activity in salivary glands. Transient Wnt1 overexpression in basal epithelia was induced in inducible Wnt1 transgenic mice before together with, after, or without local radiation, and then saliva flow rate, histology, apoptosis, proliferation, stem cell activity, and mRNA expression were evaluated. Results: Radiation damage did not significantly affect activity of Wnt/{beta}-catenin pathway as physical damage did. Transient expression of Wnt1 in basal epithelia significantly activated the Wnt/{beta}-catenin pathway in submandibular glands of male mice but not in those of females. Concurrent transient activation of the Wnt pathway prevented chronic salivary gland dysfunction following radiation by suppressing apoptosis and preserving functional salivary stem/progenitor cells. In contrast, Wnt activation 3 days before or after irradiation did not show significant beneficial effects, mainly due to failure to inhibit acute apoptosis after radiation. Excessive Wnt activation before radiation failed to inhibit apoptosis, likely due to extensive induction of mitosis and up-regulation of proapoptosis gene PUMA while that after radiation might miss the critical treatment window. Conclusion: These results suggest that concurrent transient activation of the Wnt/{beta}-catenin pathway could prevent radiation-induced salivary gland dysfunction.

  19. Optic radiation damage in multiple sclerosis is associated with visual dysfunction and retinal thinning - an ultrahigh-field MR pilot study

    International Nuclear Information System (INIS)

    Sinnecker, Tim; Oberwahrenbrock, Timm; Zimmermann, Hanna; Ramien, Caren; Brandt, Alexander U.; Metz, Imke; Brueck, Wolfgang; Pfueller, Caspar F.; Doerr, Jan; Harms, Lutz; Ruprecht, Klemens; Hahn, Katrin; Niendorf, Thoralf; Paul, Friedemann; Wuerfel, Jens

    2015-01-01

    To investigate posterior visual pathway damage in multiple sclerosis using ultrahigh-field magnetic resonance imaging (MRI) at 7 Tesla (7 T), and to determine its correlation with visual disability and retinal fibre layer (RNFL) damage detectable by optic coherence tomography (OCT). We studied 7 T MRI, OCT, functional acuity contrast testing (FACT), and visually evoked potentials (VEP, n = 16) in 30 patients (including 26 relapsing-remitting MS and four clinically isolated syndrome patients) and 12 healthy controls to quantify RNFL thickness, optic radiation lesion volume, and optic radiation thickness. Optic radiation lesion volume was associated with thinning of the optic radiation (p < 0.001), delayed VEP (p = 0.031), and visual disability indicated by FACT (p = 0.020). Furthermore, we observed an inverse correlation between optic radiation lesion volume and RNFL thickness (p < 0.001), including patients without previous optic neuritis (p < 0.001). Anterior visual pathway damage, but also (subclinical) optic radiation integrity loss detectable by 7 T MRI are common findings in MS that are mutually affected. Given the association between optic radiation damage, visual impairment, and increased VEP latency in this exploratory study of a limited sample size, clinicians should be aware of acute lesions within the optic radiation in patients with (bilateral) visual disturbances. (orig.)

  20. Optic radiation damage in multiple sclerosis is associated with visual dysfunction and retinal thinning - an ultrahigh-field MR pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Sinnecker, Tim [Charite - Universitaetsmedizin Berlin, NeuroCure Clinical Research Center, Berlin (Germany); Asklepios Fachklinikum Teupitz, Department of Neurology, Teupitz (Germany); Oberwahrenbrock, Timm; Zimmermann, Hanna; Ramien, Caren; Brandt, Alexander U. [Charite - Universitaetsmedizin Berlin, NeuroCure Clinical Research Center, Berlin (Germany); Metz, Imke; Brueck, Wolfgang [University Medicine Goettingen, Institute of Neuropathology, Goettingen (Germany); Pfueller, Caspar F.; Doerr, Jan [Charite - Universitaetsmedizin Berlin, NeuroCure Clinical Research Center, Berlin (Germany); Charite - Universitaetsmedizin Berlin, Clinical and Experimental Multiple Sclerosis Research Center, Berlin (Germany); Harms, Lutz; Ruprecht, Klemens [Charite - Universitaetsmedizin Berlin, Clinical and Experimental Multiple Sclerosis Research Center, Berlin (Germany); Charite - Universitaetsmedizin Berlin, Department of Neurology, Berlin (Germany); Hahn, Katrin [Charite - Universitaetsmedizin Berlin, Department of Neurology, Berlin (Germany); Niendorf, Thoralf [Max Delbrueck Center for Molecular Medicine, Berlin Ultrahigh Field Facility (B.U.F.F), Berlin (Germany); Charite - Universitaetsmedizin Berlin and Max Delbrueck Center for Molecular Medicine, Experimental and Clinical Research Center, Berlin (Germany); Paul, Friedemann [Charite - Universitaetsmedizin Berlin, NeuroCure Clinical Research Center, Berlin (Germany); Charite - Universitaetsmedizin Berlin, Clinical and Experimental Multiple Sclerosis Research Center, Berlin (Germany); Charite - Universitaetsmedizin Berlin, Department of Neurology, Berlin (Germany); Charite - Universitaetsmedizin Berlin and Max Delbrueck Center for Molecular Medicine, Experimental and Clinical Research Center, Berlin (Germany); Wuerfel, Jens [Charite - Universitaetsmedizin Berlin, NeuroCure Clinical Research Center, Berlin (Germany); Max Delbrueck Center for Molecular Medicine, Berlin Ultrahigh Field Facility (B.U.F.F), Berlin (Germany); University Medicine Goettingen, Institute of Neuroradiology, Goettingen (Germany)

    2015-01-15

    To investigate posterior visual pathway damage in multiple sclerosis using ultrahigh-field magnetic resonance imaging (MRI) at 7 Tesla (7 T), and to determine its correlation with visual disability and retinal fibre layer (RNFL) damage detectable by optic coherence tomography (OCT). We studied 7 T MRI, OCT, functional acuity contrast testing (FACT), and visually evoked potentials (VEP, n = 16) in 30 patients (including 26 relapsing-remitting MS and four clinically isolated syndrome patients) and 12 healthy controls to quantify RNFL thickness, optic radiation lesion volume, and optic radiation thickness. Optic radiation lesion volume was associated with thinning of the optic radiation (p < 0.001), delayed VEP (p = 0.031), and visual disability indicated by FACT (p = 0.020). Furthermore, we observed an inverse correlation between optic radiation lesion volume and RNFL thickness (p < 0.001), including patients without previous optic neuritis (p < 0.001). Anterior visual pathway damage, but also (subclinical) optic radiation integrity loss detectable by 7 T MRI are common findings in MS that are mutually affected. Given the association between optic radiation damage, visual impairment, and increased VEP latency in this exploratory study of a limited sample size, clinicians should be aware of acute lesions within the optic radiation in patients with (bilateral) visual disturbances. (orig.)

  1. Investigation of Friction-induced Damage to the Pig Cornea

    NARCIS (Netherlands)

    da Cruz Barros, Raquel; Van Kooten, Theo G.; Veeregowda, Deepak Halenahally

    2015-01-01

    Mechanical friction causes damage to the cornea. A friction measurement device with minimal intervention with the pig cornea tear film revealed a low friction coefficient of 0.011 in glycerine solution. Glycerine molecules presumably bind to water, mucins, and epithelial cells and therewith improve

  2. Mechanisms for radiation damage in DNA. Progress report, November 1, 1978-October 31, 1979

    International Nuclear Information System (INIS)

    Sevilla, M.D.

    1979-07-01

    Several mechanisms for radiation damage to DNA constituents and DNA are proposed, and a series of experiments utilizing electron spin resonance spectrometry to test the proposed mechanisms are detailed. In the past we have concentrated chiefly on the direct affect of radiation on DNA. We are currently investigating systems of DNA constituents and peptides which may shed light on indirect effects. Studies which have been completed during the past year include: (1) studies of γ-irradiated N-acetyl amino acids and peptide solutions at 77 0 K; and (2) studies of barriers to hindered rotation in peptide radicals. Studies in which progress has been made in this past year include: (1) π cations produced in DNA bases by hydroxyl radical attack; and (2) studies of spin transfer in γ-Irradiated nucleoside-peptide solutions. These studies have shown that: (1) frozen aqueous solutions provide a suitable matrix for γ irradiation studies; (2) γ-irradiated peptides in frozen aqueous solutions follow chemistry expected from previous studies; and (3) π cations of DNA base can be produced by hydroxyl radical attack

  3. Protection from radiation-induced damage to spermatogenesis by hormone treatment

    International Nuclear Information System (INIS)

    Kurdoglu, B.; Wilson, G.; Parchuri, N.; Ye, W.; Meistrich, M.L.

    1994-01-01

    Infertility caused by killing of the spermatogonial stem cells occurs frequently in men treated for cancer with radiotherapy and chemotherapy. We investigated whether pretreatment of rats with testosterone plus estradiol, which reversibly inhibits the completion of spermatogenesis and protects spermatogonial stem cells from procarbazine-induced damage, would also protect these cells from radiation. Adult male LBNF rats were implanted for 6 weeks with capsules containing testosterone and estradiol and then irradiated with doses from 2.5-7.0 Gy. Controls were irradiated with 1.8-3.5 Gy. Implants were removed 1 day after irradiation, and all animals were killed 10 weeks later for assessment of stem cell survival by counting repopulating tubules in histological sections and by sperm head counts. At doses of 2.5 and 3.5 Gy the repopulation indices and sperm head counts were significantly higher (P < 0.001) in the rats treated with testosterone and estradiol than in the controls. Protection factors calculated from the dose-response curves were in the range of 1.5-2.2. Elucidation of the mechanism of protection is essential to apply it to clinical situations. The fact that the spermatogonia are protected against radiation as well as procarbazine indicates that the mechanism does not involve drug delivery or metabolism. 32 refs., 3 figs

  4. Effect of radiation damage on operating safety of steel pressure vessels of nuclear reactors

    International Nuclear Information System (INIS)

    Vacek, M.; Havel, S.; Stoces, B.; Brumovsky, M.

    1980-01-01

    The effects are assessed of the environment upon mechanical properties of steel used generally for pressure vessels of light water nuclear reactors. Changes caused by radiation affect the reliability of vessels. Deterioration of steel properties is mainly due to neutron radiation. The article deals with factors bearing upon damage and with methods allowing to evaluate the reliability of vessels and predict their service life. Operating reliability of vessels is very unfavourably affected by planned and accidental reactor transients. (author)

  5. Repair of radiation damage of Micrococcus radioproteolyticus due to gamma and UV irradiation

    International Nuclear Information System (INIS)

    Ryznar, L.; Drasil, V.

    1982-01-01

    Cells were irradiated in dry state with gamma radiation and UV radiation. The post-irradiation warming of freeze dried cells (2 hours to 60deg or to 80deg) influenced the ability to repair sublethal damage. Heating to 80deg caused a mild reduction in survival. The repair of irradiated and heated cells required more time than that of cells which had only been irradiated. (M.D.)

  6. Consequences of PAI-1 specific deletion in endothelium on radiation-induced intestinal damage

    International Nuclear Information System (INIS)

    Rannou, Emilie

    2015-01-01

    Radiation-induced injury to healthy tissues is a real public health problem, since they are one of the most limiting factors that restrict efficiency of radiation therapy. This problematic is also part of the French Cancer Plan 2014-2017, and involves clinical research. Concepts surrounding the development of radiation-induced damage have gradually evolved into a contemporary and integrated view of the pathogenesis, involving all compartments of target tissue. Among them, endothelium seems to be central in the sequence of interrelated events that lead to the development of radiation-induced damage, although there are rare concrete elements that support this concept. By using new transgenic mouse models, this PhD project provides a direct demonstration of an endothelium-dependent continuum in evolution of radiation-induced intestinal damage. Indeed, changes in the endothelial phenotype through targeted deletion of the gene SERPINE1, chosen because of its key role in the development of radiation enteritis, influences various parameters of the development of the disease. Thus, lack of PAI-1 secretion by endothelial cells significantly improves survival of the animals, and limits severity of early and late tissue damage after a localized small bowel irradiation. Furthermore, these mice partially KO for PAI-1 showed a decrease in the number of apoptotic intestinal stem cells in the hours following irradiation, a decrease in the macrophages infiltrate density one week after irradiation, and a change in the polarization of macrophages throughout the pathophysiological process. In an effort to protect healthy tissues from radiation therapy side effects, without hindering the cancer treatment, PAI-1 seems to be an obvious therapeutic target. Conceptually, this work represents the direct demonstration of the link between endothelium phenotype and radiation enteritis pathogenesis. (author)

  7. A review of thermographic techniques for damage investigation in composites

    Directory of Open Access Journals (Sweden)

    Laura Vergani

    2014-01-01

    Full Text Available The aim of this work is a review of scientific results in the literature, related to the application of thermographic techniques to composite materials. Thermography is the analysis of the surface temperature of a body by infrared rays detection via a thermal-camera. The use of this technique is mainly based on the modification of the surface temperature of a material, when it is stimulated by means of a thermal or mechanical external source. The presence of defects, in fact, induces a localized variation in its temperature distribution and, then, the measured values of the surface temperature can be used to localize and evaluate the dimensions and the evolution of defects. In the past, many applications of thermography were proposed on homogeneous materials, but only recently this technique has also been extended to composites. In this work several applications of thermography to fibres reinforced plastics are presented. Thermographic measurements are performed on the surface of the specimens, while undergoing static and dynamic tensile loading. The joint analysis of thermal and mechanical data allows one to assess the damage evolution and to study the damage phenomenon from both mechanical and energetic viewpoints. In particular, one of the main issues is to obtain information about the fatigue behaviour of composite materials, by following an approach successfully applied to homogenous materials. This approach is based on the application of infrared thermography on specimens subjected to static or stepwise dynamic loadings and on the definition of a damage stress, D, that is correlated to the fatigue strength of the material. A wide series of experimental fatigue tests has been carried out to verify if the value of the damage stress, D, is correlated with the fatigue strength of the material. The agreement between the different values is good, showing the reliability of the presented thermographic techniques, to the study of composite

  8. Radiation damage in silicon due to albedo neutrons emitted from hadronic beam dumps (Fe and U)

    International Nuclear Information System (INIS)

    Gabriel, T.A.; Bishop, B.L.

    1987-01-01

    Calculations have been carried out to determine the level of radiation damage that can be expected from albedo neutrons when 1- and 5-GeV negative pions are incident on iron and uranium beam dumps. The calculated damage data are presented in several ways including neutron fluence above 0.111 MeV, 1 MeV equivalent neutron fluence, damage energy deposition, and DPA or displacements per atom. Details are presented as to the method of calculation. 14 refs., 1 fig., 1 tab

  9. Reliability aspects of radiation damage in reactor pressure vessel mterials

    International Nuclear Information System (INIS)

    Brumovsky, M.

    1985-01-01

    The service life estimate is a major factor in the evaluation of the operating reliability and safety of a nuclear reactor pressure vessel. The evaluation of the service life of the pressure vessel is based on a comparison of fracture toughness values with stress intensity factors. Notch toughness curves are used for the indirect determination of fracture toughness. The dominant degradation effect is radiation embrittlement. Factors having the greatest effect on the result are the properties of the starting material of the vessel and the impurity content, mainly the Cu and P content. The design life is affected by the evaluation of residual lifetime which is made by periodical nondestructive inspections and using surveillance samples. (M.D.)

  10. Damage Precursor Investigation of Fiber-Reinforced Composite Materials Under Fatigue Loads

    Science.gov (United States)

    2013-09-01

    capability, needs Maintenance Action Damage Detection by NDE and/or in-situ sensors (Ultrasonic, Thermography , Acoustic Emission, etc.) Incipient... Damage Prognosis for Materials and Structures in Complex Systems, AFOSR Discovery Challenge Thrust (DCT) Workshop on Prognosis of Aircraft and Space... Damage Precursor Investigation of Fiber-Reinforced Composite Materials Under Fatigue Loads by Asha J. Hall, Raymond E. Brennan IV, Anindya

  11. The features of radiation damages in L-alanine crystals

    International Nuclear Information System (INIS)

    Zaitov, V.R.; Onischuk, V.A.

    1996-01-01

    The method of the ESR alanine dosimetry has appeared the most convenient one for measurement of radiation dose in the range 1-10 6 Gy. Its peculiarities are the wide dose range, the high accuracy, the absence fading at room temperature, the possibility of many times repeated measurements as dosemeter accumulates dose, the simplicity of measurements. Because of this performance ESR alanine dosimetry technique can be applied to continuous monitoring radiation doses absorbed by materials on nuclear power stations as well as of dose fields and restoration doses after an accident situation. In order to determine accurately the absorbed dose in an accident on background of accumulated dose for previous period, it is necessary to the utmost increase the accuracy of dosimetry system. For this reason it is necessary to know how the properties of free radicals which formings in irradiated L-alanine are displayed in signal ESR. With the purpose to detect the structure of the free radicals the ESR spectra the L-alanine and L-alanine-d 3 single crystals were studied. The samples were grown by slow evaporation of the saturated aqueous solution. For obtain the L-alanine-d 3 the three-divisible recrystallization in heavy water had been used. The samples were irradiated with 60 Co at room temperature and in liquid nitrogen. The irradiation doses were 10 kGy and dose rate was 8,3 Gy/s. To increase the resolution of the ESR spectra hyperfine structure the second derivative for the absorption curve was registered. The measurements were conducted in X-range at temperatures 77-430 K. (author)

  12. Depletion layer recombination effects on the radiation damage hardness of gallium arsenide cells

    Science.gov (United States)

    Garlick, G. F. J.

    1985-01-01

    The significant effect of junction depletion layer recombination on the efficiency of windowed GaAs cells was demonstrated. The effect becomes more pronounced as radiation damage occurs. The depletion is considered for 1 MeV electron fluences up to 10 to the 16th power e/sq m. The cell modeling separates damage in emitter and base or buffer layers using different damage coefficients is reported. The lower coefficient for the emitter predicts less loss of performance at fluences greater than 10 to the 15th power e/sq cm. A method for obtaining information on junction recombination effects as damage proceeds is described; this enables a more complete diagnosis of damage to be made.

  13. Radiation damage and materials performance in irradiation environment

    International Nuclear Information System (INIS)

    Singh, B.N.

    2009-01-01

    Collisions of energetic projectile particles with host atoms produce atomic displacements in the target materials. Subsequently, some of these displacements are transformed into lattice defects and survive in the form of single defects and of defect clusters. Depending on the ambient temperature, these defects and their clusters diffuse, interact, annihilate, segregate and accumulate in various forms and are responsible for the evolution of the irradiation-induced microstructure. Naturally, both physical and mechanical properties and thereby the performance and lifetime of target materials are likely to be determined by the nature and the magnitude of the accumulated defects and their spatial dispositions. The defect accumulation, microstructural evolution and the resulting materials response gets very complicated particularly under the reactor operational conditions. The complication arises from the fact that the materials used in the structural components will experience concurrently generation of defects produced by the flux of neutrons and generation of dislocations due to plastic deformation. In other words, the defect accumulation will have to be considered under the conditions of two interactive reaction kinetics operating simultaneously. Both materials and experimental variables are likely to affect the damage accumulation and thereby the materials performance. Experimental and theoretical results pertaining to effects of major materials and experimental variables on materials performance will be briefly examined. (au)

  14. Radiation damage in materials. Primary knock-on atom energy analyses of cascade damage

    International Nuclear Information System (INIS)

    Sekimura, Naoto

    1995-01-01

    To understand cascade damage formation as a function of primary recoil energy, thin foils of gold were irradiated with 20 - 400 keV self-ions to 1.0 x 10 14 ions/m 2 at 300 K. Yield of groups of vacancy clusters saturated at ion energy higher than 100 keV. Number of clusters in a group had variation even from the same energy ions. Size distribution of the clusters was not strongly dependent on number of clusters in a group and ion energy. Density of vacancy clusters in a group formed near the specimen surface was calibrated to estimate vacancy cluster formation in neutron-irradiated material. A model was proposed to predict distribution of defect clusters in the irradiated materials based on a primary recoil spectrum. Examples of recomposed distribution of vacancy clusters in a group in irradiated gold were compared with the measured data. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-01-01

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

  16. On radiation damage to normal tissues and its treatment. Pt. 2

    International Nuclear Information System (INIS)

    Michalowski, A.S.

    1994-01-01

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

  17. Recovery From Radiation-induced Bone Marrow Damage by HSP25 Through Tie2 Signaling

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hae-June [Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Kwon, Hee-Chung [Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Chung, Hee-Yong [College of Medicine, Hanyang University, Seoul (Korea, Republic of); Lee, Yoon-Jin [Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Lee, Yun-Sil, E-mail: yslee0425@ewha.ac.kr [College of Pharmacy and Division of Life and Pharmaceutical Sciences, Ewha Woman' s University, Seoul (Korea, Republic of)

    2012-09-01

    Purpose: Whole-body radiation therapy can cause severe injury to the hematopoietic system, and therefore it is necessary to identify a novel strategy for overcoming this injury. Methods and Materials: Mice were irradiated with 4.5 Gy after heat shock protein 25 (HSP25) gene transfer using an adenoviral vector. Then, peripheral blood cell counts, histopathological analysis, and Western blotting on bone marrow (BM) cells were performed. The interaction of HSP25 with Tie2 was investigated with mouse OP9 and human BM-derived mesenchymal stem cells to determine the mechanism of HSP25 in the hematopoietic system. Results: HSP25 transfer increased BM regeneration and reduced apoptosis following whole-body exposure to ionizing radiation (IR). The decrease in Tie2 protein expression that followed irradiation of the BM was blocked by HSP25 transfer, and Tie2-positive cells were more abundant among the BM cells of HSP25-transferred mice, even after IR exposure. Following systemic RNA interference of Tie2 before IR, HSP25-mediated radioprotective effects were partially blocked in both mice and cell line systems. Stability of Tie2 was increased by HSP25, a response mediated by the interaction of HSP25 with Tie2. IR-induced tyrosine phosphorylation of Tie2 was augmented by HSP25 overexpression; downstream events in the Tie2 signaling pathway, including phosphorylation of AKT and EKR1/2, were also activated. Conclusions: HSP25 protects against radiation-induced BM damage by interacting with and stabilizing Tie2. This may be a novel strategy for HSP25-mediated radioprotection in BM.

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

    Science.gov (United States)

    Einor, D; Bonisoli-Alquati, A; Costantini, D; Mousseau, T A; Møller, A P

    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. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. The Assessment of Primary DNA Damage in Medical Personnel Occupationally Exposed to Ionizing Radiation

    International Nuclear Information System (INIS)

    Kopjar, N.; Garaj-Vrhovac, V.

    2003-01-01

    In physico-chemical interaction with cellular DNA ionizing radiation produces a variety of primary lesions, such as single-strand breaks (SSB), alkali-labile sites, double-strand breaks (DSB), DNA-DNA and DNA-protein crosslinks, and damage to purine and pyrimidine bases. The effects of low-level exposure to ionising radiation are of concern to large number of people, including workers receiving radiation exposure on the job. It is very important to estimate absorbed doses from individuals occupationally exposed to ionising radiation for carrying out radioprotection procedures and restrict the hazards to human health. A wide range of methods is presently used for the detection of early biological effects of DNA-damaging agents in environmental and occupational settings. Currently, unstable chromosomal aberrations in peripheral blood lymphocytes, in particularly dicentrics, are the most fully developed biological indicators of ionizing radiation exposure. This methodology usually complements data obtained by physical dosimetry. As a routine, it is used whenever the individual dosimeter shows an exposure to penetrating radiation above its limit of detection. One of the advantages of cytogenetic dosimetry is that this biological dosimeter can be assessed at any moment whereas physical dosimeters are not always present in the subject. During the last years, the single cell gel electrophoresis (SCGE) or comet assay has gained widespread acceptance for genotoxicity testing. In molecular epidemiology studies DNA damage evaluated by the comet assay is utilized as a biomarker of exposure. The comet assay permits the detection of primary DNA damage and the study of repair kinetics at the level of single cells. The aim of the present study was to assess and quantificate the levels of DNA damage in peripheral blood leukocytes of medical workers occupationally exposed to ionizing radiation and corresponding unexposed control subjects. As a sensitive biomarker of exposure the

  20. Study of radiation damages in AISI 316 and 347 steels

    International Nuclear Information System (INIS)

    Santos, G.R. dos.

    1993-03-01

    The CV-28 cyclotron at IEN (Nuclear Engineering Institute) has been used to simulated, in a short time scale, uniform He concentrations produced during neutron irradiation of metals by (n, α) reactions. Helium was implanted at concentrations of 1 to 300 ppm in 100 μm thick sheet samples of AISI 316 and 347 S S by degrading a 28 MeV alpha particle beam with a rotating energy degrader. The effects of He on the mechanical properties of the steels were studied by both non-destructive (positron annihilation) and destructive tests (tensile, creep, TEM and SEM). The positron lifetime measurements of irradiated and annealed samples were used as the base to discuss the He diffusion mechanism. Activation energies of 0.34±0.04 eV for 316 S S and 0.57±0.06 eV for 347 S S, characterized a dissociative process above 650 0 C. TEM analyses have suggested the Ostwald ripening process for bubble growth over the full range of He concentrations studied. It was shown, in agreement with theoretical calculations that, by themselves the displacements produced during the helium implantation, at rate of 1.8 x 10 -3 d pa/ppm, were not sufficient to cause significant changes in ductility. However, a strong ductility loss with increasing He concentration was observed for both types of steel for tensile tests at 25 0 C, as well as in creep at 750 0 C over the range of strain (100 to 200 MPa). Finally, it was shown that charged particle simulation associated with positron annihilation techniques provides a fast, relatively low cost, and useful method to study different kinds of neutron damage in materials. (author)

  1. Scintillation and radiation damage of doped BaF2 crystals

    International Nuclear Information System (INIS)

    Gong Zufang; Xu Zizong; Chang Jin

    1992-01-01

    The emission spectra and the radiation damage of BaF 2 crystals doped Ce and Dy have been studied. The results indicate that the doped BaF 2 crystals have the intrinsic spectra of impurity besides the intrinsic spectra of BaF 2 crystals. The crystals colored and the transmissions decrease with the concentration of impurity in BaF 2 crystals after radiation by γ-ray of 60 Co. The doped Ce BaF 2 irradiated by ultraviolet has faster recover of transmissions but for doped Dy the effect is not obvious. The radiation resistance is not good as pure BaF 2 crystals

  2. Emergency response activities and collecting damaged radiation devices from a war affected area in Croatia

    International Nuclear Information System (INIS)

    Subasic, Damir; Schaller, Antum

    1997-01-01

    A number of various devices containing ionizing radiation sources were in use in the area affected by the recent war in Croatia. In destruction caused by the war operations, a number of these devices were damaged, destroyed or even missed/lost. The actions undertaken to (re)collect these radiation sources, experience gained and lessons learned are reviewed. The importance of a well-organized national regulatory system is highlighted as a precondition for the efficient identification and safe collection of radiation sources which were under ruins. Experience from this event could be well applicable to similar situations caused by disasters and particularly for regulatory authorities who design emergency preparedness plans. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-03-28

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

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

    Science.gov (United States)

    Angeluts, A. A.; Gapeyev, A. B.; Esaulkov, M. N.; Kosareva, O. G.; Matyunin, S. N.; Nazarov, M. M.; Pashovkin, T. N.; Solyankin, P. M.; Cherkasova, O. P.; Shkurinov, A. P.

    2014-03-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-07-01

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

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

    International Nuclear Information System (INIS)

    Averbeck, D.; Boucher, D.

    2006-01-01

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

  7. Theory of the high base resistivity n(+)pp(+) silicon solar cell and its application to radiation damage effects

    Science.gov (United States)

    Goradia, C.; Weinberg, I.

    1985-01-01

    Particulate radiation in space is a principal source of silicon solar cell degradation, and an investigation of cell radiation damage at higher base resistivities appears to have implication toward increasing solar cell and, therefore, useful satellite lifetimes in the space environment. However, contrary to expectations, it has been found that for cells with resistivities of 84 and 1250 ohm cm, the radiation resistance decreases as cell base resistivity increases. An analytical solar-cell computer model was developed with the objective to determine the reasons for this unexpected behavior. The present paper has the aim to describe the analytical model and its use in interpreting the behavior, under irradiation, of high-resistivity solar cells. Attention is given to boundary conditions at the space-charge region edges, cell currents, cell voltages, the generation of the theoretical I-V characteristic, experimental results, and computer calculations.

  8. Radiation-induced oxidative damage to the DNA-binding domain of the lactose repressor

    Czech Academy of Sciences Publication Activity Database

    Gillard, N.; Goffinont, S.; Buré, C.; Davídková, Marie; Maurizot, J. C.; Cadene, M.; Spotheim-Maurizot, M.

    2007-01-01

    Roč. 403, part 3 (2007), s. 463-472 ISSN 0264-6021 R&D Projects: GA MŠk 1P05OC085 Institutional research plan: CEZ:AV0Z10480505 Keywords : ionizing radiation * oxidative damage * DNA binding domain * lac repressor Subject RIV: CE - Biochemistry Impact factor: 4.009, year: 2007

  9. ESR study of radiation damage in pyrimidines. Progress report, August 1, 1975--April 1, 1976

    International Nuclear Information System (INIS)

    Benson, B.W.

    1976-04-01

    The primary objective of this project is to develop general mechanisms for radiation damage to biomolecules using substituted pyrimidines as a model system. Results this year include a single crystal ESR study of 5-ethyl-5-isopropylbarbituric acid, development of the k-band microwave bridge, dose response measurements on methylated barbituric acid derivatives, and synthesis of several specifically deuterated uracil derivatives

  10. RADAMOL tool: Role of radiation quality and charge transfer in damage distribution along DNA oligomer

    Czech Academy of Sciences Publication Activity Database

    Štěpán, Václav; Davídková, Marie

    2014-01-01

    Roč. 68, č. 8 (2014), s. 240-247 ISSN 1434-6060 R&D Projects: GA MŠk LD12008; GA MŠk MP1002 Nano-IBCT Grant - others:GA MŠk(CZ) LM2010005 Institutional support: RVO:61389005 Keywords : radiation damage * ionizations * DNA Subject RIV: BO - Biophysics Impact factor: 1.228, year: 2014

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

    NARCIS (Netherlands)

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

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

  12. DNA damage and photosynthetic inhibition induced by solar ultraviolet radiation in tropical phytoplankton (Lake Titicaca, Bolivia)

    NARCIS (Netherlands)

    Helbling, EW; Villafane, VE; Buma, AGJ; Andrade, M; Zaratti, F

    Experiments were conducted during October 1998 in Lake Titicaca, Bolivia (16 degrees S, 68 degrees W, 3810 m a.s.l), to determine the effects of solar ultraviolet radiation (UVR) on phytoplankton photosynthetic rates and DNA damage. Water samples were taken daily and incubated ir? situ or in

  13. Implantation of keV-energy argon clusters and radiation damage in diamond

    DEFF Research Database (Denmark)

    Popok, Vladimir; Samela, Juha; Nordlund, Kai

    2012-01-01

    We show that for impacting argon clusters, both mean projected ranges of the constituents and depths of radiation damage in diamond scale linearly with momentum. The same dependence was earlier found for keV-energy cluster implantation in graphite, thus suggesting the universality of this scaling...

  14. New Modeling Approaches to Investigate Cell Signaling in Radiation Response

    Science.gov (United States)

    Plante, Ianik; Cucinotta, Francis A.; Ponomarev, Artem L.

    2011-01-01

    Ionizing radiation damages individual cells and tissues leading to harmful biological effects. Among many radiation-induced lesions, DNA double-strand breaks (DSB) are considered the key precursors of most early and late effects [1] leading to direct mutation or aberrant signal transduction processes. In response to damage, a flow of information is communicated to cells not directly hit by the radiation through signal transduction pathways [2]. Non-targeted effects (NTE), which includes bystander effects and genomic instability in the progeny of irradiated cells and tissues, may be particularly important for space radiation risk assessment [1], because astronauts are exposed to a low fluence of heavy ions and only a small fraction of cells are traversed by an ion. NTE may also have important consequences clinical radiotherapy [3]. In the recent years, new simulation tools and modeling approaches have become available to study the tissue response to radiation. The simulation of signal transduction pathways require many elements such as detailed track structure calculations, a tissue or cell culture model, knowledge of biochemical pathways and Brownian Dynamics (BD) propagators of the signaling molecules in their micro-environment. Recently, the Monte-Carlo simulation code of radiation track structure RITRACKS was used for micro and nano-dosimetry calculations [4]. RITRACKS will be used to calculate the fraction of cells traversed by an ion and delta-rays and the energy deposited in cells in a tissue model. RITRACKS also simulates the formation of chemical species by the radiolysis of water [5], notably the .OH radical. This molecule is implicated in DNA damage and in the activation of the transforming growth factor beta (TGF), a signaling molecule involved in NTE. BD algorithms for a particle near a membrane comprising receptors were also developed and will be used to simulate trajectories of signaling molecules in the micro-environment and characterize autocrine

  15. The Flaxseed-Derived Lignan Phenolic Secoisolariciresinol Diglucoside (SDG Protects Non-Malignant Lung Cells from Radiation Damage

    Directory of Open Access Journals (Sweden)

    Anastasia Velalopoulou

    2015-12-01

    Full Text Available Plant phenolic compounds are common dietary antioxidants that possess antioxidant and anti-inflammatory properties. Flaxseed (FS has been reported to be radioprotective in murine models of oxidative lung damage. Flaxseed’s protective properties are attributed to its main biphenolic lignan, secoisolariciresinol diglucoside (SDG. SDG is a free radical scavenger, shown in cell free systems to protect DNA from radiation-induced damage. The objective of this study was to investigate the in vitro radioprotective efficacy of SDG in murine lung cells. Protection against irradiation (IR-induced DNA double and single strand breaks was assessed by γ-H2AX labeling and alkaline comet assay, respectively. The role of SDG in modulating the levels of cytoprotective enzymes was evaluated by qPCR and confirmed by Western blotting. Additionally, effects of SDG on clonogenic survival of irradiated cells were evaluated. SDG protected cells from IR-induced death and ameliorated DNA damage by reducing mean comet tail length and percentage of γ-H2AX positive cells. Importantly, SDG significantly increased gene and protein levels of antioxidant HO-1, GSTM1 and NQO1. Our results identify the potent radioprotective properties of the synthetic biphenolic SDG, preventing DNA damage and enhancing the antioxidant capacity of normal lung cells; thus, rendering SDG a potential radioprotector against radiation exposure.

  16. The Flaxseed-Derived Lignan Phenolic Secoisolariciresinol Diglucoside (SDG) Protects Non-Malignant Lung Cells from Radiation Damage.

    Science.gov (United States)

    Velalopoulou, Anastasia; Tyagi, Sonia; Pietrofesa, Ralph A; Arguiri, Evguenia; Christofidou-Solomidou, Melpo

    2015-12-22

    Plant phenolic compounds are common dietary antioxidants that possess antioxidant and anti-inflammatory properties. Flaxseed (FS) has been reported to be radioprotective in murine models of oxidative lung damage. Flaxseed's protective properties are attributed to its main biphenolic lignan, secoisolariciresinol diglucoside (SDG). SDG is a free radical scavenger, shown in cell free systems to protect DNA from radiation-induced damage. The objective of this study was to investigate the in vitro radioprotective efficacy of SDG in murine lung cells. Protection against irradiation (IR)-induced DNA double and single strand breaks was assessed by γ-H2AX labeling and alkaline comet assay, respectively. The role of SDG in modulating the levels of cytoprotective enzymes was evaluated by qPCR and confirmed by Western blotting. Additionally, effects of SDG on clonogenic survival of irradiated cells were evaluated. SDG protected cells from IR-induced death and ameliorated DNA damage by reducing mean comet tail length and percentage of γ-H2AX positive cells. Importantly, SDG significantly increased gene and protein levels of antioxidant HO-1, GSTM1 and NQO1. Our results identify the potent radioprotective properties of the synthetic biphenolic SDG, preventing DNA damage and enhancing the antioxidant capacity of normal lung cells; thus, rendering SDG a potential radioprotector against radiation exposure.

  17. Investigating Radiation Shielding Properties of Different Mineral Origin Heavyweight Concretes

    Science.gov (United States)

    Basyigit, Celalettin; Uysal, Volkan; Kilinçarslan, Şemsettin; Mavi, Betül; Günoǧlu, Kadir; Akkurt, Iskender; Akkaş, Ayşe

    2011-12-01

    The radiation although has hazardous effects for human health, developing technologies bring lots of usage fields to radiation like in medicine and nuclear power station buildings. In this case protecting from undesirable radiation is a necessity for human health. Heavyweight concrete is one of the most important materials used in where radiation should be shielded, like those areas. In this study, used heavyweight aggregates of different mineral origin (Limonite, Siderite), in order to prepare different series in concrete mixtures and investigated radiation shielding properties. The experimental results on measuring the radiation shielding, the heavyweight concrete prepared with heavyweight aggregates of different mineral origin show that, are useful radiation absorbents when they used in concrete mixtures.

  18. Investigating Radiation Shielding Properties of Different Mineral Origin Heavyweight Concretes

    International Nuclear Information System (INIS)

    Basyigit, Celalettin; Uysal, Volkan; Kilincarslan, Semsettin; Akkas, Ayse; Mavi, Betuel; Guenoglu, Kadir; Akkurt, Iskender

    2011-01-01

    The radiation although has hazardous effects for human health, developing technologies bring lots of usage fields to radiation like in medicine and nuclear power station buildings. In this case protecting from undesirable radiation is a necessity for human health. Heavyweight concrete is one of the most important materials used in where radiation should be shielded, like those areas. In this study, used heavyweight aggregates of different mineral origin (Limonite, Siderite), in order to prepare different series in concrete mixtures and investigated radiation shielding properties. The experimental results on measuring the radiation shielding, the heavyweight concrete prepared with heavyweight aggregates of different mineral origin show that, are useful radiation absorbents when they used in concrete mixtures.

  19. Determining the Radiation Damage Effect on Glovebox Glove Material.

    Energy Technology Data Exchange (ETDEWEB)

    Cournoyer, M. E. (Michael E.); Balkey, J. J. (James J.); Andrade, R.M. (Rose M.)

    2005-01-01

    The Nuclear Material Technology (NMT) Division has the largest inventory of glove box gloves at Los Alamos National Laboratory. The minimization of unplanned breaches in the glovebox, e.g., glove failures, is a primary concern in the daily operations in NMT Division facilities, including the Plutonium Facility (PF-4) at TA-55 and Chemical and Metallurgy Research (CMR) Facility. Glovebox gloves in these facilities are exposed to elevated temperatures and exceptionally aggressive radiation environments (particulate {sup 239}Pu and {sup 238}Pu). Predictive models are needed to estimate glovebox glove service lifetimes, i.e. change-out intervals. Towards this aim aging studies have been initiated that correlate changes in mechanical (physical) properties with degradation chemistry. This present work derives glovebox glove change intervals based on previously reported mechanical data of thermally aged hypalon glove samples. Specifications for 30 mil tri-layered hypalon/lead glovebox gloves (TLH) and 15 mil hypalon gloves (HYP) have already been established. The relevant mechanical properties are shown on Table 1. Tensile strength is defined as the maximum load applied in breaking a tensile test piece divided by the original cross-sectional area of the test piece (Also termed maximum stress and ultimate tensile stress). Ultimate elongation is the elongation at time of rupture (Also termed maximum strain). The specification for the tensile test and ultimate elongation are the minimum acceptable values. In addition, the ultimate elongation must not vary 20% from the original value. In order to establish a service lifetimes for glovebox gloves in a thermal environment, the mechanical properties of glovebox glove materials were studied.

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

    DEFF Research Database (Denmark)

    Milhøj, Birgitte Olai

    in the reaction mechanism for the reaction between the OH radical and the DNA/RNA nucleobases. These conclusions are not only based on calculations of energies of the various intermediates as is the standard procedure in many investigations, but instead they are supported by computational calculations of rate...

  1. Nuclear Reaction Data and Uncertainties for Radiation Damage. Summary Report of the Technical Meeting

    International Nuclear Information System (INIS)

    Griffin, P.J.; Sjöstrand, H.; Simakov, S.P.

    2016-08-01

    This Meeting was organized to implement the recommendation of the second Research Coordinated Meeting (RCM) of the International Atomic Energy Agency (IAEA) Coordinated Research Project (CRP) “Primary Radiation Damage Cross Sections” to analyse the accuracy and consistency of the radiation damage-relevant nuclear data in the major nuclear data evaluations with the eventual goal of identifying the most reliable data and providing quantitative uncertainty estimates. Participants have considered the status of the primary nuclear data, such as reaction recoils spectra in the latest releases of ENDF, JEFF, JENDL, FENDL, ROSFOND and TENDL nuclear data libraries, and the ways of deriving the damage quantities KERMA, NRT- or arc-dpa and gas production cross sections as well as the recipes for an assessment of their uncertainties. This report contains the contemporary view of the Meeting participants on these issues in the form of a consolidated set of statements, recommendations and individual summaries. (author)

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

    International Nuclear Information System (INIS)

    Mickley, G.A.; Ferguson, J.L.; Nemeth, T.J.; Mulvihill, M.A.; Alderks, C.E.

    1989-01-01

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

  3. DNA damage response in a radiation resistant bacterium Deinococcus radiodurans: a paradigm shift

    International Nuclear Information System (INIS)

    Misra, H.S.

    2015-01-01

    Deinococcusradiodurans is best known for its extraordinary resistance to gamma radiation with its D 10 12kGy, and several other DNA damaging agents including desiccation to less than 5% humidity and chemical xenotoxicants. An efficient DNA double strand break (DSB) repair and its ability to protect biomolecules from oxidative damage are a few mechanisms attributed to these phenotypes in this bacterium. Although it regulates its proteome and transcriptome in response to DNA damage for its growth and survival, it lacks LexA mediated classical SOS response mechanism. Since LexA mediated damages response mechanism is highly and perhaps only, characterized DNA damage response processes in prokaryotes, this bacterium keeps us guessing how it responds to extreme doses of DNA damage. Interestingly, this bacterium encodes a large number of eukaryotic type serine threonine/tyrosine protein kinases (eST/YPK), phosphatases and response regulators and roles of eST/YPKs in cellular response to DNA damage and cell cycle regulations are well established in eukaryotes. Here, we characterized an antioxidant and DNA damage inducible eST/YPK (RqkA) and established its role in extraordinary radioresistance and DSB repair in this bacterium. We identified native phosphoprotein substrates for this kinase and demonstrated the involvement of some of these proteins phosphorylation in the regulation of DSB repair and growth under radiation stress. Findings suggesting the possible existence of eST/YPK mediated DNA damage response mechanism as an alternate to classical SOS response in this prokaryote would be discussed. (author)

  4. Does prolonged radiofrequency radiation emitted from Wi-Fi devices induce DNA damage in various tissues of rats?

    Science.gov (United States)

    Akdag, Mehmet Zulkuf; Dasdag, Suleyman; Canturk, Fazile; Karabulut, Derya; Caner, Yusuf; Adalier, Nur

    2016-09-01

    Wireless internet (Wi-Fi) providers have become essential in our daily lives, as wireless technology is evolving at a dizzying pace. Although there are different frequency generators, one of the most commonly used Wi-Fi devices are 2.4GHz frequency generators. These devices are heavily used in all areas of life but the effect of radiofrequency (RF) radiation emission on users is generally ignored. Yet, an increasing share of the public expresses concern on this issue. Therefore, this study intends to respond to the growing public concern. The purpose of this study is to reveal whether long term exposure of 2.4GHz frequency RF radiation will cause DNA damage of different tissues such as brain, kidney, liver, and skin tissue and testicular tissues of rats. The study was conducted on 16 adult male Wistar-Albino rats. The rats in the experimental group (n=8) were exposed to 2.4GHz frequency radiation for over a year. The rats in the sham control group (n=8) were subjected to the same experimental conditions except the Wi-Fi generator was turned off. After the exposure period was complete the possible DNA damage on the rat's brain, liver, kidney, skin, and testicular tissues was detected through the single cell gel electrophoresis assay (comet) method. The amount of DNA damage was measured as percentage tail DNA value. Based on the DNA damage results determined by the single cell gel electrophoresis (Comet) method, it was found that the% tail DNA values of the brain, kidney, liver, and skin tissues of the rats in the experimental group increased more than those in the control group. The increase of the DNA damage in all tissues was not significant (p>0.05). However the increase of the DNA damage in rat testes tissue was significant (pWi-Fi) does not cause DNA damage of the organs investigated in this study except testes. The results of this study indicated that testes are more sensitive organ to RF radiation. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Particle interaction and displacement damage in silicon devices operated in radiation environments

    International Nuclear Information System (INIS)

    Leroy, Claude; Rancoita, Pier-Giorgio

    2007-01-01

    Silicon is used in radiation detectors and electronic devices. Nowadays, these devices achieving submicron technology are parts of integrated circuits of large to very large scale integration (VLSI). Silicon and silicon-based devices are commonly operated in many fields including particle physics experiments, nuclear medicine and space. Some of these fields present adverse radiation environments that may affect the operation of the devices. The particle energy deposition mechanisms by ionization and non-ionization processes are reviewed as well as the radiation-induced damage and its effect on device parameters evolution, depending on particle type, energy and fluence. The temporary or permanent damage inflicted by a single particle (single event effect) to electronic devices or integrated circuits is treated separately from the total ionizing dose (TID) effect for which the accumulated fluence causes degradation and from the displacement damage induced by the non-ionizing energy-loss (NIEL) deposition. Understanding of radiation effects on silicon devices has an impact on their design and allows the prediction of a specific device behaviour when exposed to a radiation field of interest

  6. Radiation induced apoptosis and initial DNA damage are inversely related in locally advanced breast cancer patients

    International Nuclear Information System (INIS)

    Pinar, Beatriz; Henríquez-Hernández, Luis Alberto; Lara, Pedro C; Bordon, Elisa; Rodriguez-Gallego, Carlos; Lloret, Marta; Nuñez, Maria Isabel; De Almodovar, Mariano Ruiz

    2010-01-01

    DNA-damage assays, quantifying the initial number of DNA double-strand breaks induced by radiation, have been proposed as a predictive test for radiation-induced toxicity. Determination of radiation-induced apoptosis in peripheral blood lymphocytes by flow cytometry analysis has also been proposed as an approach for predicting normal tissue responses following radiotherapy. The aim of the present study was to explore the association between initial DNA damage, estimated by the number of double-strand breaks induced by a given radiation dose, and the radio-induced apoptosis rates observed. Peripheral blood lymphocytes were taken from 26 consecutive patients with locally advanced breast carcinoma. Radiosensitivity of lymphocytes was quantified as the initial number of DNA double-strand breaks induced per Gy and per DNA unit (200 Mbp). Radio-induced apoptosis at 1, 2 and 8 Gy was measured by flow cytometry using annexin V/propidium iodide. Radiation-induced apoptosis increased in order to radiation dose and data fitted to a semi logarithmic mathematical model. A positive correlation was found among radio-induced apoptosis values at different radiation doses: 1, 2 and 8 Gy (p < 0.0001 in all cases). Mean DSB/Gy/DNA unit obtained was 1.70 ± 0.83 (range 0.63-4.08; median, 1.46). A statistically significant inverse correlation was found between initial damage to DNA and radio-induced apoptosis at 1 Gy (p = 0.034). A trend toward 2 Gy (p = 0.057) and 8 Gy (p = 0.067) was observed after 24 hours of incubation. An inverse association was observed for the first time between these variables, both considered as predictive factors to radiation toxicity

  7. Can radiation damage to protein crystals be reduced using small-molecule compounds?

    Energy Technology Data Exchange (ETDEWEB)

    Kmetko, Jan [Kenyon College, Gambier, OH 43022 (United States); Warkentin, Matthew; Englich, Ulrich; Thorne, Robert E., E-mail: ret6@cornell.edu [Cornell University, Ithaca, NY 14853 (United States); Kenyon College, Gambier, OH 43022 (United States)

    2011-10-01

    Free-radical scavengers that are known to be effective protectors of proteins in solution are found to increase global radiation damage to protein crystals. Protective mechanisms may become deleterious in the protein-dense environment of a crystal. Recent studies have defined a data-collection protocol and a metric that provide a robust measure of global radiation damage to protein crystals. Using this protocol and metric, 19 small-molecule compounds (introduced either by cocrystallization or soaking) were evaluated for their ability to protect lysozyme crystals from radiation damage. The compounds were selected based upon their ability to interact with radiolytic products (e.g. hydrated electrons, hydrogen, hydroxyl and perhydroxyl radicals) and/or their efficacy in protecting biological molecules from radiation damage in dilute aqueous solutions. At room temperature, 12 compounds had no effect and six had a sensitizing effect on global damage. Only one compound, sodium nitrate, appeared to extend crystal lifetimes, but not in all proteins and only by a factor of two or less. No compound provided protection at T = 100 K. Scavengers are ineffective in protecting protein crystals from global damage because a large fraction of primary X-ray-induced excitations are generated in and/or directly attack the protein and because the ratio of scavenger molecules to protein molecules is too small to provide appreciable competitive protection. The same reactivity that makes some scavengers effective radioprotectors in protein solutions may explain their sensitizing effect in the protein-dense environment of a crystal. A more productive focus for future efforts may be to identify and eliminate sensitizing compounds from crystallization solutions.

  8. Can radiation damage to protein crystals be reduced using small-molecule compounds?

    International Nuclear Information System (INIS)

    Kmetko, Jan; Warkentin, Matthew; Englich, Ulrich; Thorne, Robert E.

    2011-01-01

    Free-radical scavengers that are known to be effective protectors of proteins in solution are found to increase global radiation damage to protein crystals. Protective mechanisms may become deleterious in the protein-dense environment of a crystal. Recent studies have defined a data-collection protocol and a metric that provide a robust measure of global radiation damage to protein crystals. Using this protocol and metric, 19 small-molecule compounds (introduced either by cocrystallization or soaking) were evaluated for their ability to protect lysozyme crystals from radiation damage. The compounds were selected based upon their ability to interact with radiolytic products (e.g. hydrated electrons, hydrogen, hydroxyl and perhydroxyl radicals) and/or their efficacy in protecting biological molecules from radiation damage in dilute aqueous solutions. At room temperature, 12 compounds had no effect and six had a sensitizing effect on global damage. Only one compound, sodium nitrate, appeared to extend crystal lifetimes, but not in all proteins and only by a factor of two or less. No compound provided protection at T = 100 K. Scavengers are ineffective in protecting protein crystals from global damage because a large fraction of primary X-ray-induced excitations are generated in and/or directly attack the protein and because the ratio of scavenger molecules to protein molecules is too small to provide appreciable competitive protection. The same reactivity that makes some scavengers effective radioprotectors in protein solutions may explain their sensitizing effect in the protein-dense environment of a crystal. A more productive focus for future efforts may be to identify and eliminate sensitizing compounds from crystallization solutions

  9. Prenatal exposure to atomic radiation and brain damage

    International Nuclear Information System (INIS)

    Otake, Masanori; Yoshimaru, Hiroshi; Schull, W.J.

    1989-01-01

    The purpose of this study was threefold: to evaluate the risks to the developing human embryonic and fetal brain of exposure to ionizing radiation using the new DS86 doses; to compare the estimate of risk so derived with those based on the earlier T65DR doses; and to present the evidence bearing on a threshold in the low dose region under the two systems of dosimetry, especially for the data on clinically recognized severe mental retardation (SMR) and seizure. Regarding dose-related SMR, IQ scores, school performance and seizures, there was a high temporal correspondence between the T65DR and DS86 dosimetry systems. A linear no-threshold model with both dosimetry systems also revealed that a significant increase in SMR was observed when the subjects were exposed in the uterus during the periods both 8-15 and 16-25 weeks after fertilization. A threshold in the low dose region was not suggested with the T65DR fetal absorbed doses, but suggested with the DS86 uterine absorbed doses. However, the location or even the existence of a threshold during both periods after fertilization was difficult to demonstrate statistically with the DS86 uterine absorbed doses. When two probable nonradiation-related cases of Down's syndrome were excluded, a threshold with a lower bound was suggested to be observed in the 0.10-0.20 Gy region. Both dosimetries indicated a threshold in the dose-response function for mental retardation in the 16-25 week period, probably within the range from 0.23 to 0.70 Gy. The seizure data provided no persuasive evidence of a threshold during the 8-15 week period after fertilization; the 95% lower bound of the estimate of the threshold included zero. Finally, although the mean IQ scores and the mean school performances in the low dose region were similar to the values in the control group, particularly with doses under 0.10 Gy, evidence for a threshold is not compelling. (N.K.)

  10. Mechanisms for radiation damage in DNA. Progress report, June 1, 1994--May 31, 1995

    International Nuclear Information System (INIS)

    Sevilla, M.D.

    1994-11-01

    In this project we have proposed several mechanisms for radiation damage to DNA and its constituents, and have detailed a series of experiments utilizing electron spin resonance spectroscopy, HPLC, GC-mass spectroscopy and ab initio molecular orbital calculations to test the proposed mechanisms. The results from these various techniques have resulted in an understanding of consequences of radiation damage to DNA from the early ionization event to the production of non-radical lesions (discussed in detail in Comprehensive Report). In this year's work we have found the hydroxyl radical in DNA's hydration layer. This is an important result which impacts the hole transfer hypothesis and the understanding of the direct vs. indirect effect in DNA. Further we have found the first ESR evidence for sugar radicals as a result of direct radiation damage to DNA nucleotides in an aqueous environment. This is significant as it impacts the biological endpoint of radiation damage to DNA and suggests future work in DNA. Work with DNA-polypeptides show clear evidence for electron transfer to DNA from the polypeptide which we believe is a radioprotective mechanism. Our work with ab initio molecular orbital theory has gain insight into the initial events of radiation damage to DNA. Ab initio calculations have provided an understanding of the energetics involved in anion and cation formation, ion radical transfer in DNA as well as proton transfer with DNA base pair radical ions. This has been extended in this year's work to new, more accurate values for the electron affinities of the DNA bases, understanding of the relative stability of all possible sugar radicals formed by hydrogen abstraction on the deoxyribose group, hydration effects on, thiol radioprotectors, and an ongoing study of radical intermediates formed from initial DNA ion radicals. During this fiscal year five articles have been published, three are in press, two are submitted and several more are in preparation

  11. A ReaXFF carbon potential for radiation damage studies

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Roger, E-mail: r.smith@lboro.ac.uk [Department of Mathematical Sciences, Loughborough University, LE11 3TU (United Kingdom); Jolley, Kenny [Department of Mathematical Sciences, Loughborough University, LE11 3TU (United Kingdom); Latham, Chris [Department of Chemistry, Surrey University, GU2 5XH (United Kingdom); Heggie, Malcolm [Department of Chemistry, Loughborough University, LE11 3TU (United Kingdom); Duin, Adri van; Duin, Diana van [RxFF Consulting, 2398 Charleston Dr., State College, PA 16801 (United States); Wu, Houzheng [Department of Materials, Loughborough University, LE11 3TU (United Kingdom)

    2017-02-15

    Highlights: • A new reactive force field potential. • Reproduces defect energies and pathways calculated from DFT. • Molecular dynamics cascades reproduce these defects. - Abstract: Although molecular dynamics simulations of energetic impacts and collision cascades in graphite have been investigated for over 25 years, recent investigations have shown a difference between the types of defects predicted by the commonly used empirical potentials compared to ab initio calculations. As a result a new ReaXFF potential has been fitted which reproduces the formation energies of many of the defects predicted by the ab initio calculations and the energy pathways between different defect states, important for investigating long term defect evolution. The data sets in the fitting have been added to the existing data sets used for modelling hydrocarbons and fullerenes. The elastic properties of the potential are less well modelled than the point defect structures with the elastic constants c33 being too high and c44 too low compared to experiment. Preliminary results of low energy collision cascades show many point defect structures develop that are in agreement with those predicted from the ab initio results.

  12. Protective effect of propolis on radiation-induced chromosomal damage on Chinese hamster ovary cells (CHO-K1)

    Energy Technology Data Exchange (ETDEWEB)

    Spigoti, Geyza; Bartolini, Paolo; Okazaki, Kayo [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], e-mail: kokazaki@ipen.br; Tsutsumi, Shiguetoshi [Amazon Food Ltd., Tokyo (Japan)], e-mail: fwip5138@mb.infoweb.ne.jp

    2009-07-01

    In the last years, particular interest has been given to investigations concerning natural, effective and nontoxic compounds with radioprotective capacity in concert with increasing utilization of different types of ionizing radiation for various applications. Among them, propolis, a resinous mixture of substances collected by honey bees (Apis mellifera) has been considered promising since it presents several advantageous characteristics, i.e., antiinflammatory, anticarcinogenic, antimicrobial and free radical scavenging action. It is, therefore, a direct antioxidant that protects cells and organisms from the adverse effects of ionizing radiation. These relevant biological activities are mainly mediated by the flavonoids, present at relatively high concentrations in the propolis. Considering that the chemical composition and, consequently, the biological activity of propolis is variable according to the environmental plant ecology, the present study was conducted in order to evaluate the radioprotective capacity of Brazilian propolis, collected in the State of Rio Grande do Sul, against genotoxic damages induced by {sup 60}Co {gamma}-radiation in Chinese hamster ovary cells (CHO-K1). for this purpose, micronucleus induction was analyzed concerning irreparable damage, specifically related to DNA double-strand breaks, that are potentially carcinogenic. CHO-K1 cells were submitted to different concentrations of propolis (3 - 33 {mu}g/ml), 1 h before irradiation, with 1 Gy of {gamma} radiation (0.722 Gy/min). The data obtained showed a decreasing tendency in the quantity of radioinduced damage on cells previously treated with propolis. The radioprotective effect was more prominent at higher propolis concentration. The treatment with propolis alone did not induce genotoxic effects on CHO-K1 cells. Beside that, the treatment with propolis, associated or not with radiation, did not influence the kinetics of cellular proliferation. (author)

  13. Protective effect of propolis on radiation-induced chromosomal damage on Chinese hamster ovary cells (CHO-K1)

    International Nuclear Information System (INIS)

    Spigoti, Geyza; Bartolini, Paolo; Okazaki, Kayo; Tsutsumi, Shiguetoshi

    2009-01-01

    In the last years, particular interest has been given to investigations concerning natural, effective and nontoxic compounds with radioprotective capacity in concert with increasing utilization of different types of ionizing radiation for various applications. Among them, propolis, a resinous mixture of substances collected by honey bees (Apis mellifera) has been considered promising since it presents several advantageous characteristics, i.e., antiinflammatory, anticarcinogenic, antimicrobial and free radical scavenging action. It is, therefore, a direct antioxidant that protects cells and organisms from the adverse effects of ionizing radiation. These relevant biological activities are mainly mediated by the flavonoids, present at relatively high concentrations in the propolis. Considering that the chemical composition and, consequently, the biological activity of propolis is variable according to the environmental plant ecology, the present study was conducted in order to evaluate the radioprotective capacity of Brazilian propolis, collected in the State of Rio Grande do Sul, against genotoxic damages induced by 60 Co γ-radiation in Chinese hamster ovary cells (CHO-K1). for this purpose, micronucleus induction was analyzed concerning irreparable damage, specifically related to DNA double-strand breaks, that are potentially carcinogenic. CHO-K1 cells were submitted to different concentrations of propolis (3 - 33 μg/ml), 1 h before irradiation, with 1 Gy of γ radiation (0.722 Gy/min). The data obtained showed a decreasing tendency in the quantity of radioinduced damage on cells previously treated with propolis. The radioprotective effect was more prominent at higher propolis concentration. The treatment with propolis alone did not induce genotoxic effects on CHO-K1 cells. Beside that, the treatment with propolis, associated or not with radiation, did not influence the kinetics of cellular proliferation. (author)

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

    Science.gov (United States)

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

    1983-01-01

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

  15. Cumulative genetic damage in children exposed to preconception and intrauterine radiation

    International Nuclear Information System (INIS)

    Bross, I.D.; Natarajan, N.

    1980-01-01

    Using a mathematical model and newly developed computer software, the data from the Tri-State Leukemia Survey involving different combinations of radiation exposures to the father and mother prior to conception and to the mother during pregnancy were analyzed. The hypothesis that radiation exposure produces genetic damage which may be expressed in the child both as indicator disease and as leukemia was tested. The genetic damage was estimated in terms of the proportion affected by a given exposure. The relative risk of leukemia and certain other indicator diseases among those affected could then be estimated. The results show that there are at least two distinguishable risk groups, one group with lower (one or two exposures); and the other group with higher (two or three) radiation exposures

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-07-10

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

  17. Site specific X-ray induced changes in organic and metal organic compounds and their influence on global radiation damage

    Energy Technology Data Exchange (ETDEWEB)

    Heintz, Desiree Ellen

    2012-07-15

    The aim of this work was to systematically investigate the effects of specific and global X-ray radiation damage to biological samples and obtain a conclusive model to describe the underlying principles. Based on the systematic studies performed in this work, it was possible to propose two conclusive mechanisms to describe X-ray induced photoreduction and global radiation damage. The influence of chemical composition, temperature and solvent on X-ray induced photoreduction was investigated by X-ray Absorption Near Edge Spectroscopy and single crystal X-ray diffraction of two B12 cofactors - cyano- and methylcobalamin - as well as iron(II) and iron(III) complexes. The obtained results revealed that X-ray induced photoreduction is a ligand dependent process, with a redox reaction taking place within the complex. It could further be shown that selective hydrogen abstraction plays an important role in the process of X-ray induced photoreduction. Based on the experimental results of this work, a model to describe X-ray induced photoreduction of metal organic complexes could be proposed. The process of X-ray induced hydrogen abstraction was further investigated in a combined X-ray and neutron diffraction study on the amino acids L-serine and L-alanine, which were used as model compounds for proteins, and the nucleoside deoxythymidine (thymidine) as a model for DNA. A damage mechanism for L-serine could be found. It involves the abstraction of two hydrogen atoms, one from the hydroxyl group and one from the adjacent methylene group. Such a hydrogen abstraction results in the formation of a carbonyl group. X-ray diffraction measurements on cyano- and methylcobalamin as well as on three metal amino acid complexes, containing nickel(II) and copper(II), respectively, were conducted to investigate the contribution of X-ray induced photoreduction to global radiation damage. Results from these measurements combined with the results from L-serine, L-alanine and thymidine allowed

  18. Clustered DNA damages induced in isolated DNA and in human cells by low doses of ionizing radiation

    Science.gov (United States)

    Sutherland, B. M.; Bennett, P. V.; Sidorkina, O.; Laval, J.; Lowenstein, D. I. (Principal Investigator)

    2000-01-01

    Clustered DNA damages-two or more closely spaced damages (strand breaks, abasic sites, or oxidized bases) on opposing strands-are suspects as critical lesions producing lethal and mutagenic effects of ionizing radiation. However, as a result of the lack of methods for measuring damage clusters induced by ionizing radiation in genomic DNA, neither the frequencies of their production by physiological doses of radiation, nor their repairability, nor their biological effects are known. On the basis of methods that we developed for quantitating damages in large DNAs, we have devised and validated a way of measuring ionizing radiation-induced clustered lesions in genomic DNA, including DNA from human cells. DNA is treated with an endonuclease that induces a single-strand cleavage at an oxidized base or abasic site. If there are two closely spaced damages on opposing strands, such cleavage will reduce the size of the DNA on a nondenaturing gel. We show that ionizing radiation does induce clustered DNA damages containing abasic sites, oxidized purines, or oxidized pyrimidines. Further, the frequency of each of these cluster classes is comparable to that of frank double-strand breaks; among all complex damages induced by ionizing radiation, double-strand breaks are only about 20%, with other clustered damage constituting some 80%. We also show that even low doses (0.1-1 Gy) of high linear energy transfer ionizing radiation induce clustered damages in human cells.

  19. Silencing of poly(ADP-ribose) glycohydrolase sensitizes lung cancer cells to radiation through the abrogation of DNA damage checkpoint

    Energy Technology Data Exchange (ETDEWEB)

    Nakadate, Yusuke [Shien-Lab, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045 (Japan); Department of Bioengineering, Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan); Kodera, Yasuo; Kitamura, Yuka [Shien-Lab, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045 (Japan); Tachibana, Taro [Department of Bioengineering, Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan); Tamura, Tomohide [Division of Thoracic Oncology, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045 (Japan); Koizumi, Fumiaki, E-mail: fkoizumi@ncc.go.jp [Division of Thoracic Oncology, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045 (Japan)

    2013-11-29

    Highlights: •Radiosensitization by PARG silencing was observed in multiple lung cancer cells. •PAR accumulation was enhanced by PARG silencing after DNA damage. •Radiation-induced G2/M arrest and checkpoint activation were impaired by PARG siRNA. -- Abstract: Poly(ADP-ribose) glycohydrolase (PARG) is a major enzyme that plays a role in the degradation of poly(ADP-ribose) (PAR). PARG deficiency reportedly sensitizes cells to the effects of radiation. In lung cancer, however, it has not been fully elucidated. Here, we investigated whether PARG siRNA contributes to an increased radiosensitivity using 8 lung cancer cell lines. Among them, the silencing of PARG induced a radiosensitizing effect in 5 cell lines. Radiation-induced G2/M arrest was largely suppressed by PARG siRNA in PC-14 and A427 cells, which exhibited significantly enhanced radiosensitivity in response to PARG knockdown. On the other hand, a similar effect was not observed in H520 cells, which did not exhibit a radiosensitizing effect. Consistent with a cell cycle analysis, radiation-induced checkpoint signals were not well activated in the PC-14 and A427 cells when treated with PARG siRNA. These results suggest that the increased sensitivity to radiation induced by PARG knockdown occurs through the abrogation of radiation-induced G2/M arrest and checkpoint activation in lung cancer cells. Our findings indicate that PARG could be a potential target for lung cancer treatments when used in combination with radiotherapy.

  20. Influence of radiation-damages on parameters of lattice oscillations in crystalline and vitreous SiO2

    International Nuclear Information System (INIS)

    Abdukadyrova, I.Kh.

    2008-01-01

    Using IR reflection spectroscopy, the influence of radiation-induced disturbances on a number of parameters of lattice oscillations in two SiO 2 modifications was investigated. Radiation kinetics of changes in spectral characteristics of fundamental oscillations in SiO 2 crystalline and glassy states was determined. Dose dependences of both reflectivity and degenerate mode vibrational frequency were found to show minima whose locations were governed by a type of a sample. Under higher doses of neutron radiation (10 21 cm -2 ), certain characteristics of bands were observed to be of the same values for the both materials modified. The features of radiation kinetics were found for dynamic parameters of the samples. It was deduced that specific character of radiation-induced changes observed in spectral and dynamic parameters of oscillations in the region of degenerate modes was due to both the accumulation of radiation damages and a change in the force field surrounding bridge-type bonds which was related with the change in the SiO 2 structure. (authors)

  1. The use of recombinant DNA techniques to study radiation-induced damage, repair and genetic change in mammalian cells

    International Nuclear Information System (INIS)

    Thacker, J.

    1986-01-01

    A brief introduction is given to appropriate elements of recombinant DNA techniques and applications to problems in radiobiology are reviewed with illustrative detail. Examples are included of studies with both 254 nm ultraviolet light and ionizing radiation and the review progresses from the molecular analysis of DNA damage in vitro through to the nature of consequent cellular responses. The review is dealt with under the following headings: Molecular distribution of DNA damage, The use of DNA-mediated gene transfer to assess damage and repair, The DNA double strand break: use of restriction endonucleases to model radiation damage, Identification and cloning of DNA repair genes, Analysis of radiation-induced genetic change. (UK)

  2. Investigation of radiation defects in solids using the EXAFS method

    International Nuclear Information System (INIS)

    Eritsyan, G.N.

    1983-01-01

    The exafs method is proposed as a more informative, universal one to investigate the radiation defects in solids. The successful results as obtained by the author using the synchrotron radiation source are reported for the first time. The measurements were carried out in GaAsP crystals irradiated with 50 MeV electrons

  3. Repair of radiation-induced DNA damage in rat epidermis as a function of age

    International Nuclear Information System (INIS)

    Sargent, E.V.; Burns, F.J.

    1985-01-01

    The rate of repair of radiation-induced DNA damage in proliferating rat epidermal cells diminished progressively with increasing age of the animal. The dorsal skin was irradiated with 1200 rad of 0.8 MeV electrons at various ages, and the amount of DNA damage was determined as a function of time after irradiation by the method of alkaline unwinding followed by S 1 nuclease digestion. The amount of DNA damage immediately after irradiation was not age dependent, while the rate of damage removal from the DNA decreased with increasing age. By fitting an exponential function to the relative amount of undamaged DNA as a function of time after irradiation, DNA repair halftimes of 20, 27, 69, and 107 min were obtained for 28, 100-, 200-, and 400-day-old animals, respectively

  4. Repair of endogenous and ionizing radiation-induced DNA damages: mechanisms and biological functions

    International Nuclear Information System (INIS)

    Boiteux, S.

    2002-01-01

    The cellular DNA is continuously exposed to endogenous and exogenous stress. Oxidative stress due to cellular metabolism is the major cause of endogenous DNA damage. On the other hand, ionizing radiation (IR) is an important exogenous stress. Both induce similar DNA damages: damaged bases, abasic sites and strand breakage. Most of these lesions are lethal and/or mutagenic. The survival of the cell is managed by efficient and accurate DNA repair mechanisms that remove lesions before their replication or transcription. DNA repair pathways involved in the removal of IR-induced lesions are briefly described. Base excision repair (BER) is mostly involved in the removal of base damage, abasic sites and single strand breaks. In contrast, DNA double strand breaks are mostly repaired by non-homologous end joining (NHEJ) or homologous recombination (HR). How DNA repair pathways prevent cancer process is also discussed. (author)

  5. Image dissector photocathode solar damage test program. [solar radiation shielding using a fast optical lens

    Science.gov (United States)

    Smith, R. A.

    1977-01-01

    Image dissector sensors of the same type which will be used in the NASA shuttle star tracker were used in a series of tests directed towards obtaining solar radiation/time damage criteria. Data were evaluated to determine the predicted level of operability of the star tracker if tube damage became a reality. During the test series a technique for reducing the solar damage effect was conceived and verified. The damage concepts are outlined and the test methods and data obtained which were used for verification of the technique's feasibility are presented. The ability to operate an image dissector sensor with the solar image focussed on the photocathode by a fast optical lens under certain conditions is feasible and the elimination of a mechanical protection device is possible.

  6. Radiation damage in dielectric and semiconductor single crystals (direct observation)

    CERN Document Server

    Adawi, M A; Varichenko, V S; Zaitsev, A M

    1998-01-01

    The surfaces of boron-doped synthetic and natural diamonds have been investigated by using the scanning tunnelling microscope (STM) and the scanning electronic microscope (SEM) before and after irradiating the samples with sup 4 sup 0 Ar (25 MeV), sup 8 sup 4 Kr (210 MeV) and sup 1 sup 2 sup 5 Xe (124 MeV) ions. The structures observed after irradiation showed craters with diameters ranging from 3 nm up to 20 nm, which could be interpreted as single ion tracks and multiple hits of ions at the nearest positions of the surface. In the case of argon ion irradiation, the surface was found to be completely amorphous, but after xenon irradiation one could see parts of surface without amorphism. This can be explained by the influence of high inelastic energy losses. The energy and temperature criteria of crater formation as a result of heavy ion irradiation are introduced.

  7. Rock Burst Intensity Classification Based on the Radiated Energy with Damage Intensity at Jinping II Hydropower Station, China

    Science.gov (United States)

    Chen, Bing-Rui; Feng, Xia-Ting; Li, Qing-Peng; Luo, Ru-Zhou; Li, Shaojun

    2015-01-01

    Based on the radiated energy of 133 rock bursts monitored by a microseismic technique at the Jinping II hydropower station, in Sichuan province, China, we analyzed the advantages and disadvantages of qualitative classification methods for the rock burst intensity. Then, we investigated the characteristics, magnitude, and laws of the radiated energy, as well as the relationship between the rock burst radiated energy and intensity. Then, we selected the energy as an evaluation index for the rock burst intensity classification, and proposed a new rock burst intensity quantitative classification method, which utilized the hierarchical clustering analysis technique with the complete-linkage method. Next, we created a new set of criteria for the quantitative classification of the rock burst intensity based on radiated energy and surrounding rock damage severity. The new criteria classified the rock burst intensity into five levels: extremely intense, intense, moderate, weak, and none, and the common logarithms of the radiated energy of each level were >7 lg( E/J), >4 lg( E/J) and 2 lg( E/J) and 1 lg( E/J) and <2 lg( E/J), and <1 lg( E/J), respectively. Finally, we investigated the factors influencing the classification, and verified its feasibility and applicability via several practical rock burst examples.

  8. The prevention of radiation-induced DNA damage and apoptosis in human intestinal epithelial cells by salvianic acid A

    Directory of Open Access Journals (Sweden)

    Yanjun Zhang

    2014-07-01

    Full Text Available The topic of radiation always provokes public debate, and the uses of radiation for therapeutic and other purposes have always been associated with some anxiety. Salvia miltiorrhiza Bunge has been widely used for the treatment of various diseases including cerebrovascular diseases, coronary artery diseases, and myocardial infarction. Salvianolic acid A (SAA d (+-(3,4-dihydroxyphenyl lactic acid is the principal effective, watersoluble constituent of Salvia miltiorrhiza Bunge. In our present study, radiation-induced DNA damage and apoptosis in human intestinal epithelial cells (HIEC in the presence and absence of SAA were examined. We investigated the effects of SAA on ROS formation and the activity of enzymatic antioxidants (SOD, the lipid peroxidative index and the levels of non-enzymatic antioxidant (GSH. Finally, we investigated whether the reduction of radiation-induced cell death caused by SAA might be related to mitochondria-dependent apoptosis. Present findings indicate that SAA is a promising radioprotective agent with a strong antioxidant activity. SAA exerted its protective action on the proliferative activity of HIEC cells as evidenced by decreased cytotoxicity after exposure to γ-radiation. It is possible that SAA achieved its radioprotective action, at least in part, by enhancing DNA repair and the activity of antioxidant enzymes, by scavenging ROS and by inhibiting the mitochondria-dependent apoptotic pathway.

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

    International Nuclear Information System (INIS)

    Sobehart, Leonardo 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, the United Kingdom Compensation Scheme for Radiation-linked Diseases and the United States Energy Employees Occupational Illness Compensation Program are described. (author)

  10. Ultraviolet Radiation-Induced Cytogenetic Damage in White, Hispanic and Black Skin Melanocytes: A Risk for Cutaneous Melanoma

    Energy Technology Data Exchange (ETDEWEB)

    Dasgupta, Amrita [Hampton University Skin of Color Research Institute, Hampton, VA 23668 (United States); Katdare, Meena, E-mail: mkatdare@gmail.com [Hampton University Skin of Color Research Institute, Hampton, VA 23668 (United States); Department of Dermatology, Eastern Virginia Medical School, Norfolk, VA 23507 (United States)

    2015-08-14

    Cutaneous Melanoma (CM) is a leading cause of cancer deaths, with reports indicating a rising trend in the incidence rate of melanoma among Hispanics in certain U.S. states. The level of melanin pigmentation in the skin is suggested to render photoprotection from the DNA-damaging effects of Ultraviolet Radiation (UVR). UVR-induced DNA damage leads to cytogenetic defects visualized as the formation of micronuclei, multinuclei and polymorphic nuclei in cells, and a hallmark of cancer risk. The causative relationship between Sun exposure and CM is controversial, especially in Hispanics and needs further evaluation. This study was initiated with melanocytes from White, Hispanic and Black neonatal foreskins which were exposed to UVR to assess their susceptibility to UVR-induced modulation of cellular growth, cytogenetic damage, intracellular and released melanin. Our results show that White and Hispanic skin melanocytes with similar levels of constitutive melanin are susceptible to UVR-induced cytogenetic damage, whereas Black skin melanocytes are not. Our data suggest that the risk of developing UVR-induced CM in a skin type is correlated with the level of cutaneous pigmentation and its ethnic background. This study provides a benchmark for further investigation on the damaging effects of UVR as risk for CM in Hispanics.

  11. Cytogenetic damages induced in vivo in human lymphocytes by environmental chemicals or radiation

    International Nuclear Information System (INIS)

    Cebulska-Wasilewska, A.

    1999-01-01

    The importance of various environmental exposures has been evident in variation in cancer incidence and mortality. Benzene is considered to be a human carcinogen, is clastogenic to rodents and humans, and it affects the immune response. Workers in various industrial plants, are exposed to benzene and benzene related compounds as a result of various activities in which benzene is processed, generated or used. Major sources of environmental exposure to benzene related compounds, continue to be active and passive smoking, auto exhaust, and driving or riding in automobiles. Benzene is of a particular interest, not only because of its known toxicity, but also because this was to be the parent compound and a model for extensive programs of metabolism of a variety of aromatic chemicals. Ionizing radiation is an unavoidable physical agent that is presented in environment, and public opinion is well aware against radiation risk and strongly against it. The aim of the presentation was comparison between cytogenetic damages induced in vivo by environmental chemicals with those of radiation. Results from biomonitoring survey on genotoxicity in human blood cells of benzene and benzene related compounds were compared to damages detected in lymphocytes of persons who had been accidentally exposed to gamma radiation. In the groups, that had been occupationally or environmentally exposed to benzene related compound, total aberration frequencies, or percent of aberrant cells ranged between 0 - 0.16 aberrations/cell or 16% of aberrant cells respectively. A multivariate regression analysis confirmed: (i) a significant association between cytogenetic damage and exposure to benzene related compound, (ii) a possible association between cytogenetic damage and cancer, (iii) a significant influence of smoking habit. In 1996 few persons were suspected of accidental exposure to gamma radiation. To estimate the absorbed doses, lymphocytes from their blood have been analyzed for the presence of

  12. Radiation Mitigating Properties of Intranasally Administered KL4Surfactant in a Murine Model of Radiation-Induced Lung Damage.

    Science.gov (United States)

    Christofidou-Solomidou, Melpo; Pietrofesa, Ralph A; Arguiri, Evguenia; Koumenis, Constantinos; Segal, Robert

    2017-11-01

    The threat of exposure to ionizing radiation from a nuclear reactor accident or deliberate terrorist actions is a significant public health concern. The lung is particularly susceptible to radiation-induced injury from external sources or inhalation of radioactive particles from radioactive fallout. Radiation-induced lung disease can manifest with an acute radiation pneumonitis and/or delayed effects leading to pulmonary fibrosis. As prior warning of radiation exposure is unlikely, medical countermeasures (MCMs) to mitigate radiation-induced lung disease that can be given in mass-casualty situations many hours or days postirradiation are needed to prevent both early and late lung damage. In this study, KL 4 surfactant (lucinactant) was evaluated as a radiation mitigator in a well-characterized mouse model of targeted thoracic radiation exposure, for its effect on both early (several weeks) and late (18 weeks) lung damage. Here, 120 mg/kg total phospholipid of KL 4 surfactant was administered twice daily intranasally, (enabling intrapulmonary inhalation of drug) to C57BL/6 mice 24 h after a single 13.5 Gy dose of thoracic irradiation (LD 50 dose). Both early and chronic phase (2 and 4 weeks and 18 weeks postirradiation, respectively) assessments were performed. Mice were evaluated for evidence of reduced arterial blood oxygenation and early and chronic lung and systemic inflammation, lung fibrosis and oxidative stress. Analysis was done by performing lung function/respiration dynamics and measuring cellular protein content of bronchoalveolar lavage fluid (BALF), and levels of cytokines, 8-iso-prostaglandin F2α, hydroxyproline in lung and plasma, along with evaluating lung histology. The results of this study showed that intranasal delivery of KL 4 surfactant was able to preserve lung function as evidenced by adequate arterial oxygen saturation and reduced lung inflammation and oxidative stress; total white count and absolute neutrophil count was decreased in BALF

  13. Spectrometric properties and radiation damage of BGO crystals

    Science.gov (United States)

    Kim, Gen C.; Gasanov, Eldar M.

    1997-07-01

    Spectrometric properties, such as light output, energy resolution BGO crystals before and after (superscript 60)Co gamma-ray (dose 10(superscript 4) - 10(superscript 6) R) and neutron irradiation (fluence 10(superscript 14) cm(superscript -2)) are investigated. Condition for degradation of spectrometric properties and their recovering after irradiation are studied. The energy spectrum of the photons emitted from BGO crystals irradiated with neutron fluence contains the long living background peak which is caused by self-irradiation with radioactive isotopes produced in the crystals. The defect production was studied in crystals under the high dose gamma-irradiation with (superscript 60)Co isotope. It was found that after doses above 10(superscript 8) R the color center at 365 nm and doses higher than 10(superscript 9) R a wide absorption band in the region of 300 - 350 nm occur. Comparison of these results with those of reactor irradiation has shown that under the high dose gamma-irradiation the structure defect production takes place.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-06-01

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

  15. Common genomic signaling among initial DNA damage and radiation-induced apoptosis in peripheral blood lymphocytes from locally advanced breast cancer patients

    DEFF Research Database (Denmark)

    Henríquez-Hernández, Luis Alberto; Pinar, Beatriz; Carmona-Vigo, Ruth

    2013-01-01

    PURPOSE: To investigate the genomic signaling that defines sensitive lymphocytes to radiation and if such molecular profiles are consistent with clinical toxicity; trying to disclose the radiobiology mechanisms behind these cellular processes. PATIENTS AND METHODS: Twelve consecutive patients...... suffering from locally advanced breast cancer and treated with high-dose hyperfractionated radiotherapy were recruited. Initial DNA damage was measured by pulsed-field gel electrophoresis and radiation-induced apoptosis was measured by flow cytometry. Gene expression was assessed by DNA microarray. RESULTS...

  16. Histamine protects bone marrow against cellular damage induced by ionising radiation.

    Science.gov (United States)

    Medina, Vanina A; Croci, Máximo; Carabajal, Eliana; Bergoc, Rosa M; Rivera, Elena S

    2010-04-01

    Based on our previous data on the histamine radioprotective effect on small intestine, in the present work we aimed to determine whether histamine is able to protect bone marrow cells against ionising radiation damage. 56 mice and 40 rats were divided into four groups. Histamine and histamine-irradiated groups received a daily subcutaneous histamine injection (0.1 mg/kg) starting 24 h before irradiation. Irradiated groups received a single dose on whole-body using Cesium-137 source and were sacrificed three days after irradiation. We evaluated the number of medullar components, bone marrow trophism, oedema, vascular damage, and other histological characteristics and also proliferation markers by immunohistochemistry. Histamine treatment substantially reduced the grade of aplasia, the oedema and vascular damage induced by ionising radiation on bone marrow of mice and rats. Additionally, histamine preserved medullar components increasing the number of megakaryocytes (14.0 +/- 1.0 vs. 7.3 +/- 1.0 in mice; and 9.9 +/- 1.3 vs. 4.1 +/- 1.0 in rats, P effect was associated with an increased proliferation rate of bone marrow cells. Histamine reduces ionising radiation toxicity on bone marrow cells being a suitable candidate for use as radioprotector, especially for patients undergoing radiotherapy who are at the risk of bone marrow or small intestine damage.

  17. Asymmetry of radiation damage properties in Al–Ti nanolayers

    International Nuclear Information System (INIS)

    Setyawan, Wahyu; Gerboth, Matthew; Yao, Bo; Henager, Charles H.; Devaraj, Arun; Vemuri, Venkata R.S.R.; Thevuthasan, Suntharampillai; Shutthanandan, Vaithiyalingam

    2014-01-01

    Molecular dynamics (MD) simulations were employed with empirical potentials to study the effects of multilayer interfaces and interface spacing in Al–Ti nanolayers. Several model interfaces derived from stacking of close-packed layers or face-centered cubic {1 0 0} layers were investigated. The simulations reveal significant and important asymmetries in defect production with ∼60% of vacancies created in Al layers compared to Ti layers within the Al–Ti multilayer system. The asymmetry in the creation of interstitials is even more pronounced. The asymmetries cause an imbalance in the ratio of vacancies and interstitials in films of dissimilar materials leading to >90% of the surviving interstitials located in the Al layers. While in the close-packed nanolayers the interstitials migrate to the atomic layers adjacent to the interface of the Al layers, in the {1 0 0} nanolayers the interstitials migrate to the center of the Al layers and away from the interfaces. The degree of asymmetry and defect ratio imbalance increases as the layer spacing decreases in the multilayer films. Underlying physical processes are discussed including the interfacial strain fields and the individual elemental layer stopping power in nanolayered systems. In addition, experimental work was performed on low-dose (10 16 atoms/cm 2 ) helium (He) irradiation on Al/Ti nanolayers (5 nm per film), resulting in He bubble formation ∼1 nm in diameter in the Ti film near the interface. The correlation between the preferential flux of displaced atoms from Ti films to Al films during the defect production that is revealed in the simulations and the morphology and location of He bubbles from the experiments is discussed

  18. Effect of prior hyperthermia on subsequent thermal enhancement of radiation damage in mouse intestine

    International Nuclear Information System (INIS)

    Marigold, J.C.L.; Hume, S.P.

    1982-01-01

    Hyperthermia given in conjunction with X-rays results in a greater level of radiation injury than following X-rays alone, giving a thermal enhancement ratio (TER). The effect of prior hyperthermia ('priming') on TER was studied in the small intestine of mouse by giving 42.0 deg C for 1 hour at various times before the combined heat and X-ray treatments. Radiation damage was assessed by measuring crypt survival 4 days after radiation. TER was reduced when 'priming' hyperthermia was given 24-48 hours before the combined treatments. The reduction in effectiveness of the second heat treatment corresponded to a reduction in hyperthermal temperature of approximately 0.5 deg C, a value similar to that previously reported for induced resistance to heat given alone ('thermotolerance') (Hume and Marigold 1980). However, the time courses for development and decay of the TER response were much longer than those for 'thermotolerance', suggesting that different mechanisms are involved in thermal damage following heat alone and thermal enhancement of radiation damage

  19. New Modeling Approaches to Study DNA Damage by the Direct and Indirect Effects of Ionizing Radiation

    Science.gov (United States)

    Plante, Ianik; Cucinotta, Francis A.

    2012-01-01

    DNA is damaged both by the direct and indirect effects of radiation. In the direct effect, the DNA itself is ionized, whereas the indirect effect involves the radiolysis of the water molecules surrounding the DNA and the subsequent reaction of the DNA with radical products. While this problem has been studied for many years, many unknowns still exist. To study this problem, we have developed the computer code RITRACKS [1], which simulates the radiation track structure for heavy ions and electrons, calculating all energy deposition events and the coordinates of all species produced by the water radiolysis. In this work, we plan to simulate DNA damage by using the crystal structure of a nucleosome and calculations performed by RITRACKS. The energy deposition events are used to calculate the dose deposited in nanovolumes [2] and therefore can be used to simulate the direct effect of the radiation. Using the positions of the radiolytic species with a radiation chemistry code [3] it will be possible to simulate DNA damage by indirect effect. The simulation results can be compared with results from previous calculations such as the frequencies of simple and complex strand breaks [4] and with newer experimental data using surrogate markers of DNA double ]strand breaks such as . ]H2AX foci [5].